Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/09/14


AREA FORECAST DISCUSSION
NWS PHOENIX AZ
230 PM MST WED MAY 7 2014 .UPDATE...UPDATED AVIATION DISCUSSION... && .SYNOPSIS... PACIFIC LOW PRESSURE WILL CONTINUE TO MOVE THROUGH THE REGION TODAY...BRINGING COOLER TEMPERATURES AND ANOTHER ROUND OF AFTERNOON BREEZES. WINDS ARE NOT EXPECTED AS STRONG AS THOSE OBSERVED TUESDAY...WITH ONLY ISOLATED GUSTS POSSIBLE IN THE AFTERNOON. FORECAST DAYTIME HIGHS WILL FALL WELL BELOW NORMAL AT MANY DESERT LOCATIONS THROUGH THURSDAY. DRY AND WARMER WEATHER IS ON TAP FRIDAY AND THROUGH THE WEEKEND AS HIGH TEMPERATURES CLIMB BACK INTO THE 90S ACROSS THE LOWER DESERTS. && .DISCUSSION... COLD FRONT FROM YESTERDAY IS NOW IN NEW MEXICO BUT A FAIRLY TIGHT SURFACE PRESSURE GRADIENT REMAINS ACROSS THE FORECAST AREA AND THUS SOME BREEZINESS CAN BE EXPECTED AS THE DAY PROGRESSES BUT MUCH LESS WIND THAN YESTERDAY. MEANWHILE THE UPPER REMAINS OVER THE INTERIOR WEST WITH 12Z PLOT DATA INDICATING THE NORTH-SOUTH ORIENTED AXIS OVER WESTERN UTAH AND WESTERN ARIZONA WITH THE CENTER OF THE UPPER CIRCULATION OVER WESTERN UTAH. SATELLITE IMAGERY SHOWS A FAIR AMOUNT OF MID CLOUDS OVER NORTHERN AND EASTERN ARIZONA. SATELLITE IMAGERY ALSO SHOWS A VORT LOBE ROUNDING THE BOTTOM OF THE TROUGH OVER SOUTHERN ARIZONA. UVV ASSOCIATED WITH THIS FEATURE WILL BE SHIFTING TO NEW MEXICO BY AFTERNOON. COLD AIR ALOFT WILL ALLOW FOR SOME MEAGER CAPE...MAINLY OVER NORTHERN ARIZONA...BUT BOTH 12Z NAM AND GFS HAVE MORE CIN THAN CAPE. A TRAILING SHORT WAVE TONIGHT WILL HAVE EVEN LESS LIFT THAN THE ONE FOR TODAY. SO...SLIGHT CHANCES OF PRECIP OVER SOME HIGHER TERRAIN PORTIONS OF THE FORECAST AREA WILL BE ABOUT THE MOST WE CAN MUSTER. OTHERWISE...JUST SOME MID CLOUDS. OTHERWISE...FORECAST TEMPS ON TRACK FOR A NICE COOL DAY TODAY. && .PREVIOUS DISCUSSION ISSUED 206 AM... SHARPLY DEFINED PACIFIC TROUGH CONTINUES TO SLOWLY CIRCULATE INTO THE REGION...WITH THE TROUGH AXIS NEARING THE COLORADO RIVER VALLEY THIS MORNING. NEARLY CLEAR SKIES LEFT OVER THE WHOLE CWA IN THE WAKE OF THE VIGOROUS COLD FRONT PASSAGE TUESDAY. SOME EARLY EVENING/OVERNIGHT LIGHT SHOWER ACTIVITY CONTINUES NEAR THE COLD CORE OF THE TROUGH OVER SOUTHERN NEVADA AND TO A LESSER EXTENT SOUTHEAST CALIFORNIA...WITH MOST SITES ONLY REPORTING OVERCAST SKIES AND A HUNDREDTH OR TWO OF PRECIP ACROSS THE SOUTHERN NEVADA STATIONS. WATER VAPOR LOOP AND POTENTIAL VORTICITY MODEL OVERLAY PLOT A POCKET OF ENHANCED VORTICITY/SPIN COMING AROUND THE TROUGH BOTTOM AND ACROSS THE CA/INTL BORDER THIS MORNING. THIS VORT LOBE IS PROGGED THROUGH CENTRAL ARIZONA BY MIDDAY BEFORE QUICKLY DIFFUSING AND CLEARING EAST THIS EVENING. MOISTURE TRANSPORT AND PWATS NOT OVERLY FAVORABLE FOR SIGNIFICANT SHOWER ACTIVITY...WITH THE BEST PWATS OF NEAR HALF AN INCH OVER THE COLORADO RIVER VALLEY BY MIDDAY AND NOT EXTENDING MUCH FURTHER EAST. EVENING RUNS OF THE HI-RES HRRR AND ARW SHOW ANY SHOWER ACTIVITY DEVELOPING ACROSS NORTHERN ARIZONA THROUGH THE DAY AS THE TROUGH CONTINUES THROUGH THE AREA...WITH ONLY VERY SPOTTY DEVELOPMENT SKIRTING ACROSS THE NORTHERN PORTIONS OF MARICOPA AND GILA COUNTIES THROUGH THE AFTERNOON. SLIGHT CHANCE POPS WERE KEPT ACROSS THE HIGHER TERRAIN TO THE NORTH/EAST OF PHOENIX...WITH MENTION DROPPING OFF AFTER 08/03Z (8PM LOCAL) ONCE HEATING SUPPORT IS LOST WITH SUNSET. SIGNIFICANT COOLING OBSERVED BEHIND THE COLD FRONT...AS MUCH AS 10 DEGREES FROM THE SFC UP THROUGH 400MB VIA THE KVEF 00Z RAOB AND 6-8 DEGREES FROM KFGZ...WILL KEEP TEMPERATURES TODAY AND THURSDAY WELL BELOW SEASONAL NORMALS. LOOK FOR MID TO UPPER 70S ACROSS THE SOUTH- CENTRAL ARIZONA DESERTS WITH SLIGHTLY WARMER VALUES ACROSS THE WESTERN FORECAST AREA IN THE LOW 80S WEDNESDAY AND WIDESPREAD 80S AREAWIDE FOR THURSDAY UNDER MOSTLY CLEAR SKIES. BY FRIDAY...TROUGHING WILL HAVE MOSTLY CLEARED THE AREA WITH DRY WEST TO NORTHWESTERLY FLOW OVERTAKING THE REGION. TEMPERATURES WILL REBOUND BACK TOWARDS EARLY MAY NORMALS WITH LOW TO MID 90 DEGREE READINGS IN STORE FOR THE WEEKEND. ANOTHER LOW PRESSURE SYSTEM WILL DROP OUT OF THE PACIFIC NORTHWEST LATE SATURDAY INTO SUNDAY...BUT CURRENT THINKING FROM WPC AND THE BETTER PERFORMING OPERATIONAL/ENSEMBLE RUNS OF THE ECMWF KEEP THE BULK OF THE ENERGY AND ANY PRECIPITATION WELL TO OUR NORTH THROUGH MUCH OF THE GREAT BASIN STATES AND ONLY SKIRTING THE FAR NORTHERN PORTIONS OF ARIZONA. COULD SEE SOME ENHANCED BREEZINESS AS SOME GRADIENT TIGHTENING IS FORECAST...BUT VERY STRONG WINDS ARE NOT EXPECTED AT THIS TIME. 500MB HEIGHTS AND THICKNESSES WILL SEE SOME DECREASE...WHICH WILL KEEP DAYTIME TEMPERATURES FROM TAKING OFF TOO RAPIDLY FOR EARLY NEXT WEEK AND STAYING CLOSER TOWARDS NORMAL READINGS IN THE LOW TO MID 90S. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... WINDS CONTINUE TO REMAIN BREEZY TO GUSTY INTO THE LATE AFTERNOON AND EVENING HOURS...GUSTS TO 25 KTS OR SO ARE POSSIBLE. PREDOMINANTLY FROM THE WEST-SOUTHWEST DIRECTION AND SHOULD SWING TO AN EASTERLY HEADING BY 12Z THURSDAY MORNING. EXPECT LOWER CLOUD DECKS...8-10KT FEET TO LINGER THROUGH THE EVENING HOURS. LINGERING DUST/HAZE SHOULD IMPROVE AS MIXING CONTINUES...BUT MAY HANG AROUND THROUGH THE EVENING. VISIBILITIES SHOULD NOT BE IMPACTED BY HAZE. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... ELEVATED WINDS ACROSS SOUTHEAST CALIFORNIA TAF SITES AS WEATHER SYSTEM DEPARTS TO THE EAST WILL TAPER OFF AFTER SUNSET. HOLDING WESTERLY DIRECTION...WINDS SHOULD REMAIN BREEZY WITH GUSTS BELOW 25 KTS. MOSTLY CLEAR SKIES WITH SOME CU DECKS 8-10 KT FT POSSIBLE ESPECIALLY NEAR KBLH. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... SATURDAY THROUGH WEDNESDAY... DRY NORTHWEST FLOW ALOFT WILL SETTLE IN ACROSS THE AREA INTO THE WEEKEND...ALLOWING FOR A GRADUAL WARMING TREND WITH DESERT HIGHS CLIMBING INTO THE MID 90S BY SATURDAY. HUMIDITIES WILL BE ON THE LOW SIDE...RANGING FROM SINGLE DIGITS TO THE LOW TEENS EACH DAY. A WEATHER DISTURBANCE PASSING BY TO THE NORTH OVER THE WEEKEND WILL LEAD TO LOCALLY BREEZY CONDITIONS DURING THE AFTERNOON AND EVENING HOURS SATURDAY AND SUNDAY. EVEN HIGHER PRESSURE ALOFT WILL THEN BUILD BACK INTO THE DESERT SOUTHWEST EARLY NEXT WEEK FOR LIGHTER WIND...ALONG WITH WARMER AND DRIER CONDITIONS. BY NEXT TUESDAY EXPECT THE WARMER DESERTS TO EXCEED 100 DEGREES...AND MINIMUM HUMIDITIES TO FALL WELL BELOW 10 PERCENT OVER THE DRIER LOWER DESERT. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...AJ PREVIOUS DISCUSSION...NOLTE AVIATION...CDEWEY FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
955 AM MST WED MAY 7 2014 .SYNOPSIS... PACIFIC LOW PRESSURE WILL CONTINUE TO MOVE THROUGH THE REGION TODAY...BRINGING COOLER TEMPERATURES AND ANOTHER ROUND OF AFTERNOON BREEZES. WINDS ARE NOT EXPECTED AS STRONG AS THOSE OBSERVED TUESDAY...WITH ONLY ISOLATED GUSTS POSSIBLE IN THE AFTERNOON. FORECAST DAYTIME HIGHS WILL FALL WELL BELOW NORMAL AT MANY DESERT LOCATIONS THROUGH THURSDAY. DRY AND WARMER WEATHER IS ON TAP FRIDAY AND THROUGH THE WEEKEND AS HIGH TEMPERATURES CLIMB BACK INTO THE 90S ACROSS THE LOWER DESERTS. && .DISCUSSION... COLD FRONT FROM YESTERDAY IS NOW IN NEW MEXICO BUT A FAIRLY TIGHT SURFACE PRESSURE GRADIENT REMAINS ACROSS THE FORECAST AREA AND THUS SOME BREEZINESS CAN BE EXPECTED AS THE DAY PROGRESSES BUT MUCH LESS WIND THAN YESTERDAY. MEANWHILE THE UPPER REMAINS OVER THE INTERIOR WEST WITH 12Z PLOT DATA INDICATING THE NORTH-SOUTH ORIENTED AXIS OVER WESTERN UTAH AND WESTERN ARIZONA WITH THE CENTER OF THE UPPER CIRCULATION OVER WESTERN UTAH. SATELLITE IMAGERY SHOWS A FAIR AMOUNT OF MID CLOUDS OVER NORTHERN AND EASTERN ARIZONA. SATELLITE IMAGERY ALSO SHOWS A VORT LOBE ROUNDING THE BOTTOM OF THE TROUGH OVER SOUTHERN ARIZONA. UVV ASSOCIATED WITH THIS FEATURE WILL BE SHIFTING TO NEW MEXICO BY AFTERNOON. COLD AIR ALOFT WILL ALLOW FOR SOME MEAGER CAPE...MAINLY OVER NORTHERN ARIZONA...BUT BOTH 12Z NAM AND GFS HAVE MORE CIN THAN CAPE. A TRAILING SHORT WAVE TONIGHT WILL HAVE EVEN LESS LIFT THAN THE ONE FOR TODAY. SO...SLIGHT CHANCES OF PRECIP OVER SOME HIGHER TERRAIN PORTIONS OF THE FORECAST AREA WILL BE ABOUT THE MOST WE CAN MUSTER. OTHERWISE...JUST SOME MID CLOUDS. OTHERWISE...FORECAST TEMPS ON TRACK FOR A NICE COOL DAY TODAY. && .PREVIOUS DISCUSSION ISSUED 206 AM... SHARPLY DEFINED PACIFIC TROUGH CONTINUES TO SLOWLY CIRCULATE INTO THE REGION...WITH THE TROUGH AXIS NEARING THE COLORADO RIVER VALLEY THIS MORNING. NEARLY CLEAR SKIES LEFT OVER THE WHOLE CWA IN THE WAKE OF THE VIGOROUS COLD FRONT PASSAGE TUESDAY. SOME EARLY EVENING/OVERNIGHT LIGHT SHOWER ACTIVITY CONTINUES NEAR THE COLD CORE OF THE TROUGH OVER SOUTHERN NEVADA AND TO A LESSER EXTENT SOUTHEAST CALIFORNIA...WITH MOST SITES ONLY REPORTING OVERCAST SKIES AND A HUNDREDTH OR TWO OF PRECIP ACROSS THE SOUTHERN NEVADA STATIONS. WATER VAPOR LOOP AND POTENTIAL VORTICITY MODEL OVERLAY PLOT A POCKET OF ENHANCED VORTICITY/SPIN COMING AROUND THE TROUGH BOTTOM AND ACROSS THE CA/INTL BORDER THIS MORNING. THIS VORT LOBE IS PROGGED THROUGH CENTRAL ARIZONA BY MIDDAY BEFORE QUICKLY DIFFUSING AND CLEARING EAST THIS EVENING. MOISTURE TRANSPORT AND PWATS NOT OVERLY FAVORABLE FOR SIGNIFICANT SHOWER ACTIVITY...WITH THE BEST PWATS OF NEAR HALF AN INCH OVER THE COLORADO RIVER VALLEY BY MIDDAY AND NOT EXTENDING MUCH FURTHER EAST. EVENING RUNS OF THE HI-RES HRRR AND ARW SHOW ANY SHOWER ACTIVITY DEVELOPING ACROSS NORTHERN ARIZONA THROUGH THE DAY AS THE TROUGH CONTINUES THROUGH THE AREA...WITH ONLY VERY SPOTTY DEVELOPMENT SKIRTING ACROSS THE NORTHERN PORTIONS OF MARICOPA AND GILA COUNTIES THROUGH THE AFTERNOON. SLIGHT CHANCE POPS WERE KEPT ACROSS THE HIGHER TERRAIN TO THE NORTH/EAST OF PHOENIX...WITH MENTION DROPPING OFF AFTER 08/03Z (8PM LOCAL) ONCE HEATING SUPPORT IS LOST WITH SUNSET. SIGNIFICANT COOLING OBSERVED BEHIND THE COLD FRONT...AS MUCH AS 10 DEGREES FROM THE SFC UP THROUGH 400MB VIA THE KVEF 00Z RAOB AND 6-8 DEGREES FROM KFGZ...WILL KEEP TEMPERATURES TODAY AND THURSDAY WELL BELOW SEASONAL NORMALS. LOOK FOR MID TO UPPER 70S ACROSS THE SOUTH- CENTRAL ARIZONA DESERTS WITH SLIGHTLY WARMER VALUES ACROSS THE WESTERN FORECAST AREA IN THE LOW 80S WEDNESDAY AND WIDESPREAD 80S AREAWIDE FOR THURSDAY UNDER MOSTLY CLEAR SKIES. BY FRIDAY...TROUGHING WILL HAVE MOSTLY CLEARED THE AREA WITH DRY WEST TO NORTHWESTERLY FLOW OVERTAKING THE REGION. TEMPERATURES WILL REBOUND BACK TOWARDS EARLY MAY NORMALS WITH LOW TO MID 90 DEGREE READINGS IN STORE FOR THE WEEKEND. ANOTHER LOW PRESSURE SYSTEM WILL DROP OUT OF THE PACIFIC NORTHWEST LATE SATURDAY INTO SUNDAY...BUT CURRENT THINKING FROM WPC AND THE BETTER PERFORMING OPERATIONAL/ENSEMBLE RUNS OF THE ECMWF KEEP THE BULK OF THE ENERGY AND ANY PRECIPITATION WELL TO OUR NORTH THROUGH MUCH OF THE GREAT BASIN STATES AND ONLY SKIRTING THE FAR NORTHERN PORTIONS OF ARIZONA. COULD SEE SOME ENHANCED BREEZINESS AS SOME GRADIENT TIGHTENING IS FORECAST...BUT VERY STRONG WINDS ARE NOT EXPECTED AT THIS TIME. 500MB HEIGHTS AND THICKNESSES WILL SEE SOME DECREASE...WHICH WILL KEEP DAYTIME TEMPERATURES FROM TAKING OFF TOO RAPIDLY FOR EARLY NEXT WEEK AND STAYING CLOSER TOWARDS NORMAL READINGS IN THE LOW TO MID 90S. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... UPPER LOW WILL CONTINUE TO MOVE EAST ACROSS THE AREA TODAY INTO TONIGHT. EXPECT SCT-BKN CU/SC DECKS TO DEVELOP ACROSS THE CENTRAL DESERTS LATER THIS MORNING...CONTINUING INTO THE AFTERNOON HOURS WITH BASES GENLY 8-10K FEET. NO PRECIP EXPECTED AT THE TAF SITES...ONLY ACROSS HIGHER ELEVATIONS NORTH/EAST OF PHOENIX. WINDS TO STAY MOSTLY OUT OF THE WEST THIS MORNING...INCREASING AND BECOMING LOCALLY GUSTY BY LATE MORNING OR EARLY AFTN. MAY SEE A FEW GUSTS TO 25KT OR SO BY AFTN. WINDS TO TAPER OFF AFTER SUNSET...SKIES TO BECOME MOSTLY CLEAR. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... UPPER LOW WILL CONTINUE TO MOVE EAST ACROSS THE AREA TODAY...BRINGING LOCALLY GUSTY WEST WINDS TO THE TAF SITES ALONG WITH FEW-SCT CUMULUS DECKS. THERE MAY BE SOME CIGS AROUND 8-10K THIS MORNING...WITH CLOUDS THINNING BY AFTERNOON AS SUBSIDENCE MOVES INTO AREA BEHIND A COLD FRONT. EXPECT SOME WIND GUSTS TO AT LEAST 25KT AT TIMES AT KIPL THIS AFTERNOON...A BIT LESS WIND AT KBLH. WINDS TO TAPER OFF AFTER SUNSET FOLLOWING LACK OF MIXING...AND SKIES TO BECOME GENLY CLEAR. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... DRY NORTHWEST FLOW ALOFT WILL SETTLE IN ACROSS THE AREA FRIDAY INTO THE WEEKEND...ALLOWING FOR A GRADUAL WARMING TREND WITH DESERT HIGHS CLIMBING INTO THE MID 90S BY SATURDAY. HUMIDITIES WILL BE ON THE LOW SIDE...RANGING FROM SINGLE DIGITS TO THE LOW TEENS EACH DAY. A WEATHER DISTURBANCE PASSING BY TO THE NORTH OVER THE WEEKEND WILL LEAD TO LOCALLY BREEZY CONDITIONS DURING THE AFTERNOON AND EVENING HOURS SATURDAY AND SUNDAY. EVEN HIGHER PRESSURE ALOFT WILL THEN BUILD BACK INTO THE DESERT SOUTHWEST EARLY NEXT WEEK FOR LIGHTER WIND...ALONG WITH WARMER AND DRIER CONDITIONS. BY NEXT TUESDAY EXPECT THE WARMER DESERTS TO EXCEED 100 DEGREES...AND MINIMUM HUMIDITIES TO FALL WELL BELOW 10 PERCENT OVER THE DRIER LOWER DESERT. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...AJ PREVIOUS DISCUSSION...NOLTE AVIATION...CB FIRE WEATHER...CB
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
500 AM MST WED MAY 7 2014 .UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS. && .SYNOPSIS... PACIFIC LOW PRESSURE WILL CONTINUE TO MOVE THROUGH THE REGION TODAY...BRINGING COOLER TEMPERATURES AND ANOTHER ROUND OF AFTERNOON BREEZES. WINDS ARE NOT EXPECTED AS STRONG AS THOSE OBSERVED TUESDAY...WITH ONLY ISOLATED GUSTS POSSIBLE IN THE AFTERNOON. FORECAST DAYTIME HIGHS WILL FALL WELL BELOW NORMAL AT MANY DESERT LOCATIONS THROUGH THURSDAY. DRY AND WARMER WEATHER IS ON TAP FRIDAY AND THROUGH THE WEEKEND AS HIGH TEMPERATURES CLIMB BACK INTO THE 90S ACROSS THE LOWER DESERTS. && .DISCUSSION... SHARPLY DEFINED PACIFIC TROUGH CONTINUES TO SLOWLY CIRCULATE INTO THE REGION...WITH THE TROUGH AXIS NEARING THE COLORADO RIVER VALLEY THIS MORNING. NEARLY CLEAR SKIES LEFT OVER THE WHOLE CWA IN THE WAKE OF THE VIGOROUS COLD FRONT PASSAGE TUESDAY. SOME EARLY EVENING/OVERNIGHT LIGHT SHOWER ACTIVITY CONTINUES NEAR THE COLD CORE OF THE TROUGH OVER SOUTHERN NEVADA AND TO A LESSER EXTENT SOUTHEAST CALIFORNIA...WITH MOST SITES ONLY REPORTING OVERCAST SKIES AND A HUNDREDTH OR TWO OF PRECIP ACROSS THE SOUTHERN NEVADA STATIONS. WATER VAPOR LOOP AND POTENTIAL VORTICITY MODEL OVERLAY PLOT A POCKET OF ENHANCED VORTICITY/SPIN COMING AROUND THE TROUGH BOTTOM AND ACROSS THE CA/INTL BORDER THIS MORNING. THIS VORT LOBE IS PROGGED THROUGH CENTRAL ARIZONA BY MIDDAY BEFORE QUICKLY DIFFUSING AND CLEARING EAST THIS EVENING. MOISTURE TRANSPORT AND PWATS NOT OVERLY FAVORABLE FOR SIGNIFICANT SHOWER ACTIVITY...WITH THE BEST PWATS OF NEAR HALF AN INCH OVER THE COLORADO RIVER VALLEY BY MIDDAY AND NOT EXTENDING MUCH FURTHER EAST. EVENING RUNS OF THE HI-RES HRRR AND ARW SHOW ANY SHOWER ACTIVITY DEVELOPING ACROSS NORTHERN ARIZONA THROUGH THE DAY AS THE TROUGH CONTINUES THROUGH THE AREA...WITH ONLY VERY SPOTTY DEVELOPMENT SKIRTING ACROSS THE NORTHERN PORTIONS OF MARICOPA AND GILA COUNTIES THROUGH THE AFTERNOON. SLIGHT CHANCE POPS WERE KEPT ACROSS THE HIGHER TERRAIN TO THE NORTH/EAST OF PHOENIX...WITH MENTION DROPPING OFF AFTER 08/03Z (8PM LOCAL) ONCE HEATING SUPPORT IS LOST WITH SUNSET. SIGNIFICANT COOLING OBSERVED BEHIND THE COLD FRONT...AS MUCH AS 10 DEGREES FROM THE SFC UP THROUGH 400MB VIA THE KVEF 00Z RAOB AND 6-8 DEGREES FROM KFGZ...WILL KEEP TEMPERATURES TODAY AND THURSDAY WELL BELOW SEASONAL NORMALS. LOOK FOR MID TO UPPER 70S ACROSS THE SOUTH- CENTRAL ARIZONA DESERTS WITH SLIGHTLY WARMER VALUES ACROSS THE WESTERN FORECAST AREA IN THE LOW 80S WEDNESDAY AND WIDESPREAD 80S AREAWIDE FOR THURSDAY UNDER MOSTLY CLEAR SKIES. BY FRIDAY...TROUGHING WILL HAVE MOSTLY CLEARED THE AREA WITH DRY WEST TO NORTHWESTERLY FLOW OVERTAKING THE REGION. TEMPERATURES WILL REBOUND BACK TOWARDS EARLY MAY NORMALS WITH LOW TO MID 90 DEGREE READINGS IN STORE FOR THE WEEKEND. ANOTHER LOW PRESSURE SYSTEM WILL DROP OUT OF THE PACIFIC NORTHWEST LATE SATURDAY INTO SUNDAY...BUT CURRENT THINKING FROM WPC AND THE BETTER PERFORMING OPERATIONAL/ENSEMBLE RUNS OF THE ECMWF KEEP THE BULK OF THE ENERGY AND ANY PRECIPITATION WELL TO OUR NORTH THROUGH MUCH OF THE GREAT BASIN STATES AND ONLY SKIRTING THE FAR NORTHERN PORTIONS OF ARIZONA. COULD SEE SOME ENHANCED BREEZINESS AS SOME GRADIENT TIGHTENING IS FORECAST...BUT VERY STRONG WINDS ARE NOT EXPECTED AT THIS TIME. 500MB HEIGHTS AND THICKNESSES WILL SEE SOME DECREASE...WHICH WILL KEEP DAYTIME TEMPERATURES FROM TAKING OFF TOO RAPIDLY FOR EARLY NEXT WEEK AND STAYING CLOSER TOWARDS NORMAL READINGS IN THE LOW TO MID 90S. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... UPPER LOW WILL CONTINUE TO MOVE EAST ACROSS THE AREA TODAY INTO TONIGHT. EXPECT SCT-BKN CU/SC DECKS TO DEVELOP ACROSS THE CENTRAL DESERTS LATER THIS MORNING...CONTINUING INTO THE AFTERNOON HOURS WITH BASES GENLY 8-10K FEET. NO PRECIP EXPECTED AT THE TAF SITES...ONLY ACROSS HIGHER ELEVATIONS NORTH/EAST OF PHOENIX. WINDS TO STAY MOSTLY OUT OF THE WEST THIS MORNING...INCREASING AND BECOMING LOCALLY GUSTY BY LATE MORNING OR EARLY AFTN. MAY SEE A FEW GUSTS TO 25KT OR SO BY AFTN. WINDS TO TAPER OFF AFTER SUNSET...SKIES TO BECOME MOSTLY CLEAR. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... UPPER LOW WILL CONTINUE TO MOVE EAST ACROSS THE AREA TODAY...BRINGING LOCALLY GUSTY WEST WINDS TO THE TAF SITES ALONG WITH FEW-SCT CUMULUS DECKS. THERE MAY BE SOME CIGS AROUND 8-10K THIS MORNING...WITH CLOUDS THINNING BY AFTERNOON AS SUBSIDENCE MOVES INTO AREA BEHIND A COLD FRONT. EXPECT SOME WIND GUSTS TO AT LEAST 25KT AT TIMES AT KIPL THIS AFTERNOON...A BIT LESS WIND AT KBLH. WINDS TO TAPER OFF AFTER SUNSET FOLLOWING LACK OF MIXING...AND SKIES TO BECOME GENLY CLEAR. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... DRY NORTHWEST FLOW ALOFT WILL SETTLE IN ACROSS THE AREA FRIDAY INTO THE WEEKEND...ALLOWING FOR A GRADUAL WARMING TREND WITH DESERT HIGHS CLIMBING INTO THE MID 90S BY SATURDAY. HUMIDITIES WILL BE ON THE LOW SIDE...RANGING FROM SINGLE DIGITS TO THE LOW TEENS EACH DAY. A WEATHER DISTURBANCE PASSING BY TO THE NORTH OVER THE WEEKEND WILL LEAD TO LOCALLY BREEZY CONDITIONS DURING THE AFTERNOON AND EVENING HOURS SATURDAY AND SUNDAY. EVEN HIGHER PRESSURE ALOFT WILL THEN BUILD BACK INTO THE DESERT SOUTHWEST EARLY NEXT WEEK FOR LIGHTER WIND...ALONG WITH WARMER AND DRIER CONDITIONS. BY NEXT TUESDAY EXPECT THE WARMER DESERTS TO EXCEED 100 DEGREES...AND MINIMUM HUMIDITIES TO FALL WELL BELOW 10 PERCENT OVER THE DRIER LOWER DESERT. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...NOLTE AVIATION....CB FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
206 AM MST WED MAY 7 2014 .SYNOPSIS... PACIFIC LOW PRESSURE WILL CONTINUE TO MOVE THROUGH THE REGION TODAY...BRINGING COOLER TEMPERATURES AND ANOTHER ROUND OF AFTERNOON BREEZES. WINDS ARE NOT EXPECTED AS STRONG AS THOSE OBSERVED TUESDAY...WITH ONLY ISOLATED GUSTS POSSIBLE IN THE AFTERNOON. FORECAST DAYTIME HIGHS WILL FALL WELL BELOW NORMAL AT MANY DESERT LOCATIONS THROUGH THURSDAY. DRY AND WARMER WEATHER IS ON TAP FRIDAY AND THROUGH THE WEEKEND AS HIGH TEMPERATURES CLIMB BACK INTO THE 90S ACROSS THE LOWER DESERTS. && .DISCUSSION... SHARPLY DEFINED PACIFIC TROUGH CONTINUES TO SLOWLY CIRCULATE INTO THE REGION...WITH THE TROUGH AXIS NEARING THE COLORADO RIVER VALLEY THIS MORNING. NEARLY CLEAR SKIES LEFT OVER THE WHOLE CWA IN THE WAKE OF THE VIGOROUS COLD FRONT PASSAGE TUESDAY. SOME EARLY EVENING/OVERNIGHT LIGHT SHOWER ACTIVITY CONTINUES NEAR THE COLD CORE OF THE TROUGH OVER SOUTHERN NEVADA AND TO A LESSER EXTENT SOUTHEAST CALIFORNIA...WITH MOST SITES ONLY REPORTING OVERCAST SKIES AND A HUNDREDTH OR TWO OF PRECIP ACROSS THE SOUTHERN NEVADA STATIONS. WATER VAPOR LOOP AND POTENTIAL VORTICITY MODEL OVERLAY PLOT A POCKET OF ENHANCED VORTICITY/SPIN COMING AROUND THE TROUGH BOTTOM AND ACROSS THE CA/INTL BORDER THIS MORNING. THIS VORT LOBE IS PROGGED THROUGH CENTRAL ARIZONA BY MIDDAY BEFORE QUICKLY DIFFUSING AND CLEARING EAST THIS EVENING. MOISTURE TRANSPORT AND PWATS NOT OVERLY FAVORABLE FOR SIGNIFICANT SHOWER ACTIVITY...WITH THE BEST PWATS OF NEAR HALF AN INCH OVER THE COLORADO RIVER VALLEY BY MIDDAY AND NOT EXTENDING MUCH FURTHER EAST. EVENING RUNS OF THE HI-RES HRRR AND ARW SHOW ANY SHOWER ACTIVITY DEVELOPING ACROSS NORTHERN ARIZONA THROUGH THE DAY AS THE TROUGH CONTINUES THROUGH THE AREA...WITH ONLY VERY SPOTTY DEVELOPMENT SKIRTING ACROSS THE NORTHERN PORTIONS OF MARICOPA AND GILA COUNTIES THROUGH THE AFTERNOON. SLIGHT CHANCE POPS WERE KEPT ACROSS THE HIGHER TERRAIN TO THE NORTH/EAST OF PHOENIX...WITH MENTION DROPPING OFF AFTER 08/03Z (8PM LOCAL) ONCE HEATING SUPPORT IS LOST WITH SUNSET. SIGNIFICANT COOLING OBSERVED BEHIND THE COLD FRONT...AS MUCH AS 10 DEGREES FROM THE SFC UP THROUGH 400MB VIA THE KVEF 00Z RAOB AND 6-8 DEGREES FROM KFGZ...WILL KEEP TEMPERATURES TODAY AND THURSDAY WELL BELOW SEASONAL NORMALS. LOOK FOR MID TO UPPER 70S ACROSS THE SOUTH- CENTRAL ARIZONA DESERTS WITH SLIGHTLY WARMER VALUES ACROSS THE WESTERN FORECAST AREA IN THE LOW 80S WEDNESDAY AND WIDESPREAD 80S AREAWIDE FOR THURSDAY UNDER MOSTLY CLEAR SKIES. BY FRIDAY...TROUGHING WILL HAVE MOSTLY CLEARED THE AREA WITH DRY WEST TO NORTHWESTERLY FLOW OVERTAKING THE REGION. TEMPERATURES WILL REBOUND BACK TOWARDS EARLY MAY NORMALS WITH LOW TO MID 90 DEGREE READINGS IN STORE FOR THE WEEKEND. ANOTHER LOW PRESSURE SYSTEM WILL DROP OUT OF THE PACIFIC NORTHWEST LATE SATURDAY INTO SUNDAY...BUT CURRENT THINKING FROM WPC AND THE BETTER PERFORMING OPERATIONAL/ENSEMBLE RUNS OF THE ECMWF KEEP THE BULK OF THE ENERGY AND ANY PRECIPITATION WELL TO OUR NORTH THROUGH MUCH OF THE GREAT BASIN STATES AND ONLY SKIRTING THE FAR NORTHERN PORTIONS OF ARIZONA. COULD SEE SOME ENHANCED BREEZINESS AS SOME GRADIENT TIGHTENING IS FORECAST...BUT VERY STRONG WINDS ARE NOT EXPECTED AT THIS TIME. 500MB HEIGHTS AND THICKNESSES WILL SEE SOME DECREASE...WHICH WILL KEEP DAYTIME TEMPERATURES FROM TAKING OFF TOO RAPIDLY FOR EARLY NEXT WEEK AND STAYING CLOSER TOWARDS NORMAL READINGS IN THE LOW TO MID 90S. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... CIRRUS DECK WILL CONTINUE TO MOVE EAST...AS UPPER LEVEL LOW MOVES OVER THE REGION TONIGHT. MID LEVEL CLOUD DECKS MAY FORM OVERNIGHT WITH SCT CU AROUND 9000FT POSSIBLE OVER THE AREA. GUSTY WINDS WILL CONTINUE TO DECREASE OVERNIGHT...SETTLING IN AROUND 10KT...AND MAINTAINING A WEST-SOUTHWEST COMPONENT DURING THE TAF PERIOD. SUSPENDED DUST MAY ALSO CREATE SOME AREAS OF HAZE AND SLANT-WISE VISIBILITY ISSUES AT SOME AIRFIELDS WEDNESDAY MORNING. WINDS WILL INCREASE AGAIN WEDNESDAY AFTERNOON...WITH GUSTS UP TO 20 MPH COMMON AFTER 19Z. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... GUSTY SOUTHWEST TO WEST WINDS...UP TO 30 KTS...WILL PERSIST ACROSS SOUTHEAST CALIFORNIA THROUGH AT LEAST 06Z. WINDS TAPER OFF AT KBLH BUT WILL REMAIN ELEVATED AT KIPL UNTIL AROUND 12Z WEDNESDAY MORNING. OTHER THAN A FEW-SCT MID LEVEL CU AS UPPER LEVEL LOW MOVES OVER THE REGION TONIGHT...EXPECT MOSTLY CLEAR SKIES OVERNIGHT. WINDS WILL INCREASE AGAIN WEDNESDAY AFTERNOON...WITH GUSTS UP TO 25 MPH COMMON AFTER 19Z. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... THURSDAY THROUGH MONDAY... HIGH PRESSURE AND DRY NORTHWESTERLY FLOW ALOFT WILL BUILD EASTWARD INTO THE DESERT SOUTHWEST...AND BRING DRY CONDITIONS AND A SLOW WARMING TREND TO THE REGION THROUGH THE FORECAST PERIOD. HIGHS IN THE 80S ON THURSDAY WILL GRADUALLY WARM INTO THE MID TO UPPER 90S BY SUNDAY AND MONDAY. MINIMUM RH VALUES IN THE TEENS ON THURSDAY WILL LOWER BACK INTO THE SINGLE DIGITS OVER MUCH OF THE LOWER DESERTS BY THE WEEKEND. WINDS ARE EXPECTED TO REMAIN MOSTLY ON THE LIGHT SIDE EACH DAY...WITH JUST SOME TYPICAL AFTERNOON GUSTINESS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...NOLTE AVIATION....MEYERS FIRE WEATHER...PERCHA/CB
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
510 PM PDT THU MAY 8 2014 .SYNOPSIS...A WEAK PACIFIC STORM SYSTEM WILL BRING A CHANCE OF LIGHT RAIN TO THE SAN FRANCISCO BAY AREA AND PORTIONS OF THE CENTRAL COAST THROUGH TONIGHT. DRY CONDITIONS WILL RETURN THIS WEEKEND WITH A SIGNIFICANT WARMING TREND EXPECTED EARLY NEXT WEEK. && .DISCUSSION...AS OF 1:20 PM PDT THURSDAY...A MID/UPPER LEVEL TROUGH AND ASSOCIATED STORM SYSTEM CONTINUES TO APPROACH THE PACIFIC NORTHWEST THIS AFTERNOON. THIS FEATURE CONTINUES TO ADVECT MOISTURE INTO NORTHERN AND CENTRAL CALIFORNIA WITH LIGHT RAINFALL ALREADY BEING REPORTED ACROSS SONOMA COUNTY. EXPECTING PRECIPITATION TO GENERALLY REMAIN LIGHT AS THIS SYSTEM MOVES THROUGH THE REGION TONIGHT. SOME OF THE HIGH RESOLUTION MODELS ARE SHOWING ISOLATED LOCATIONS IN THE COASTAL MOUNTAINS OF SANTA CRUZ AND SAN MATEO COUNTIES PICKING UP AS MUCH AS 1/4" TO 1/2" OF RAINFALL TONIGHT. IT IS POSSIBLE THAT RAINFALL RATES INCREASE SOME TONIGHT AS THE FRONTAL BOUNDARY AND STRONGER SHORT-WAVE MOVES THROUGH. OVERALL...WIDESPREAD RAINFALL IS NOT EXPECTED ACROSS THE REGION TONIGHT. IN ADDITION...AREAS AROUND THE MONTEREY BAY...SALINAS VALLEY AND POINTS SOUTHWARD MAY SEE LITTLE TO NO PRECIPITATION WITH THIS SYSTEM. AS THE TROUGH EXITS THE REGION TOMORROW...NORTHWEST FLOW ALOFT DEVELOPS AND CHANCES FOR PRECIPITATION QUICKLY DIMINISH. COOLER TEMPERATURES WILL REMAIN IN PLACE ON FRIDAY AND SATURDAY WITH A PERSISTENT NORTHWEST FLOW ACROSS MUCH OF THE WEST COAST. A SLIGHT WARMING TREND WILL BEGIN LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS A RIDGE BEGINS TO BUILD ACROSS THE EASTERN PACIFIC. THE MEDIUM RANGE MODELS THEN FOCUS ON THE MID/UPPER LEVEL RIDGE STRENGTHENING AND SHIFTING TOWARD THE WEST COAST. BY THE MIDDLE OF NEXT WEEK...THE STRONG RIDGE IS FORECAST TO BE STRETCHED ALONG THE WEST COAST AND WILL LIKELY CAUSE A SIGNIFICANT WARMING TREND AND POSSIBLE OFFSHORE FLOW AT TIMES. WHILE WE REMAIN SEVERAL DAYS OUT...CANNOT RULE OUT TEMPERATURES REACHING INTO THE MID 80S IN THE SAN FRANCISCO AND MONTEREY BAY AREAS WITH MID 90S INLAND. STAY TUNED! && .AVIATION...AS OF 5:10 PM PDT THURSDAY...FOR 00Z TAFS. WEAK FRONT IS MOVING INTO THE NORTH BAY AT THIS TIME WITH SOME SPOTTY SHOWERS ACROSS THE REGION. SOMEWHAT SURPRISINGLY WINDS HAVE TURNED SOUTHEAST AT THE BUOYS AND SOME AIRPORTS. NONE OF THE MESOSCALE MODELS REALLY CAPTURED THIS BUT LATEST RAP RUN DOES AND SHOWS WINDS SWITCHING BACK TO MORE WESTERLY BY ABOUT 05-06Z THIS EVENING SO WOULD EXPECT SOUTHERLY WINDS AT KSFO FOR THE EVENING HOURS. CIGS LOOK TO GENERALLY STAY AROUND 2000 FEET OR HIGHER TONIGHT...EARLIER RAIN AT UKIAH WAS ACCOMPANIED BY BKN023. THE FRONT SHOULD BE GONE BY SUNRISE AND BRISK NW WINDS AND DRYING SHOULD MIX CIGS OUT FAIRLY EARLY WITH STRONG NW WINDS TOMORROW AFTERNOON POSSIBLE AT KSFO. VICINITY OF KSFO...EXPECT SOUTHERLY WINDS TO CONTINUE THIS EVENING AS WEAK FRONT MOVES THROUGH WITH WIND GUSTS IN EXCESS OF 15 KT. CIGS SHOULD STAY ABOVE 2000 FEET IN GENERAL WITH POSSIBLE LIGHT RAIN SHOWERS THIS EVENING. LOW TO MEDIUM CONFIDENCE. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...FRONT IS TO THE NORTH AND LOW CLOUDS WILL INCREASE AFTER 03Z ALONG THE COAST...THEN STAY IN PLACE OVERNIGHT WITH SOME VICINITY SHOWERS/DRIZZLE POSSIBLE AT KMRY. CLEARING SHOULD OCCUR BY 18Z FRIDAY WITH GUSTY NW WINDS FRIDAY AFTERNOON. MEDIUM CONFIDENCE. && .MARINE...AS OF 1:20 PM PDT THURSDAY...GENERALLY LIGHT BUT OCCASIONALLY GUSTY NORTHWEST WINDS ARE EXPECTED TONIGHT AS A COLD FRONT APPROACHES THE CENTRAL CALIFORNIA COAST. THIS WEAK COLD FRONT WILL BRING A SLIGHT CHANCE OF SHOWERS TO THE COASTAL WATERS THROUGH THIS EVENING AS IT MOVES ACROSS THE REGION. WINDS WILL BEGIN TO INCREASE AND SEA CONDITIONS WILL DETERIORATE ONCE AGAIN FRIDAY AFTERNOON AS THE SURFACE PRESSURE GRADIENT STRENGTHENS ALONG THE CALIFORNIA COAST. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 9 PM && $$ PUBLIC FORECAST: RGASS AVIATION: RWW MARINE: CW VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
901 AM PDT WED MAY 7 2014 .SYNOPSIS...A WEAK COLD FRONT WILL BRING A SLIGHT CHANCE OF LIGHT RAIN OR DRIZZLE TO THE AREA THURSDAY AND THURSDAY NIGHT. OTHERWISE DRY AND MILD WEATHER IS FORECAST THROUGH THE REMAINDER OF THE WEEK AND INTO THE UPCOMING WEEKEND. && .DISCUSSSION...AS OF 8:50 AM PDT WEDNESDAY...STRATO-CU STILL REMAINS FIRMLY ENTRENCHED ALONG THE COAST FROM SAN MATEO TO PT SUR AND INLAND THROUGH PACHECO PASS. ELSEWHERE...MOSTLY SUNNY SKIES PREVAIL THIS MORNING. FOR THE REST OF TODAY...EXPECT THE PESKY STRATO-CU TO SLOWLY ERODE BACK TO THE COAST. LATEST HI-RES MODELS... LIKE THE HRRR...KEEP CLOUDS AROUND MRY BAY AND THE SAN MATEO COAST FOR THE REST OF THE DAY. THIS SEEMS PLAUSIBLE GIVEN THE LATEST SATELLITE IMAGERY AND CONTINUED ONSHORE FLOW. THE MORE NOTABLE WEATHER FEATURE WILL BE THE STRONG NORTHERLY WINDS TODAY. THE N-S GRADIENT IS FORECAST TO INCREASE AGAIN THIS AFTERNOON...WITH VERY WINDS CONDITIONS OVER THE COASTAL WATERS AND ALONG THE COAST. NO UPDATE IS PLANNED AT THIS TIME. CURRENT FORECAST IS ON TRACK. THE NEXT FORECAST CHALLENGE WILL BE LOW CONFIDENCE RAIN CHANCES ON THURSDAY. A WEAK TROUGH IS FORECAST TO MOVE THROUGH ON THURSDAY BRINGING A SLIGHT CHANCE OF RAIN TO THE REGION. MODEL GUIDANCE CONTINUES TO SHOW THAT THE BEST CHANCE FOR PRECIP REMAINS OVER THE NORTHERN HALF OF THE CWA...OR ABOUT NORTH OF MONTEREY BAY. IF RAIN DOES FALL...AMOUNTS WILL BE LIGHT AND A ONLY A FEW HUNDREDTHS. .PREVIOUS DISCUSSION...THE UPPER LOW ASSOCIATED WITH THE THURSDAY SYSTEM IS FORECAST TO MOVE INTO THE PACIFIC NORTHWEST BY LATE FRIDAY NIGHT AND THEN INTO THE NORTHERN GREAT BASIN BY SATURDAY NIGHT. THIS COULD TIGHTEN THE SURFACE PRESSURE GRADIENTS TO RESULT IN GUSTY NORTHERLY WINDS IN OUR HILLS ON SATURDAY NIGHT AND SUNDAY MORNING. WARMER WEATHER IS EXPECTED BY SUNDAY AND INTO NEXT WEEK AS DRY NORTHERLY FLOW DEVELOPS AND AN UPPER RIDGE BEGINS TO DEVELOP NEAR THE COAST. && .AVIATION...AS OF 4:20 AM PDT WEDNESDAY...MAINLY VFR CONDITIONS WILL PREVAIL AFTER 16Z. MODERATE CONFIDENCE. ANOTHER DAY OF STRONG WEST TO NORTHWEST WINDS ARE IN STORE FOR THE REGION THIS AFTERNOON INTO THE EARLY EVENING HOURS. OTHERWISE...A STORM SYSTEM IS FORECAST TO MOVE SOUTH TOWARD THE REGION EARLY THURSDAY MORNING...BRINGING POSSIBLE MVFR CIGS AT THE VERY END OF THE FORECAST PERIOD. VICINITY OF KSFO...PATCHY LOW CLOUDS SURROUND THE BAY...WITH SFO ON THE EDGE OF CLOUDS. SCT CLOUDS MAY IMPACT THE TERMINAL THROUGH THE 16Z HOUR...LOW CONFIDENCE. OTHERWISE...WEST WINDS WILL INCREASE SIGNIFICANTLY THIS AFTERNOON...WITH WIND GUSTS TO 35 KT PROBABLE. KSFO BRIDGE APPROACH...PATCHES OF SCT LOW CLOUDS MAY IMPACT THE APPROACH THROUGH THE 16Z HOUR PREVENTING VISUALS. MONTEREY BAY AREA TERMINALS...MVFR CIGS THROUGH AT LEAST THE 18Z HOUR...LOW CONFIDENCE. NUMERICAL GUIDANCE IS ALL OVER THE PLACE WITH CLEARING TIMES...FROM 15Z TO AN ALL DAY EVENT. THE MODELS ARE IN BETTER AGREEMENT THAT KSNS WILL SEE CLEARING BETWEEN 18Z AND 19Z...WHEREAS KMRY IS A BIT MORE PESSIMISTIC. THE HRRR AND LAMP INDICATE AN ALL DAY EVENT...SO WENT WITH A LATER CLEARING TIME OF 19Z. AGAIN LOW CONFIDENCE. && .MARINE...AS OF 08:50 AM PDT WEDNESDAY...ROUGH SEAS WITH MODERATE TO OCCASIONALLY STRONG NORTHERLY WINDS WILL CONTINUE ACROSS THE WATERS THROUGH THIS EVENING. A WEAK COLD FRONT WILL PASS OVER THE WATERS LATE TONIGHT INTO THURSDAY. THIS FRONT WILL DISRUPT THE SURFACE PRESSURE GRADIENT WHICH WILL RESULT IN DECREASING WINDS AND IMPROVING SEA CONDITIONS. WINDS WILL INCREASE ONCE AGAIN FRIDAY EVENING AS THE SURFACE PRESSURE GRADIENT STRENGTHENS ALONG THE CALIFORNIA COAST. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PT REYES 0-10 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PIGEON PT TO PT PINOS 0-10 NM SCA...PT ARENA TO PT REYES 10-60 NM SCA...PT REYES TO PIGEON PT 10-60 NM SCA...PIGEON PT TO PT PINOS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM SCA...ROUGH BAR ADVISORY FOR SF BAR UNTIL 3 PM SCA...SF BAY NORTH OF THE BAY BRIDGE FROM 1 PM SCA...SF BAY SOUTH OF THE BAY BRIDGE FROM 1 PM SCA...MONTEREY BAY FROM 1 PM && $$ PUBLIC FORECAST: SIMS AVIATION: RILEY MARINE: LARRY VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
425 AM PDT WED MAY 7 2014 .SYNOPSIS...A WEAK COLD FRONT WILL BRING A SLIGHT CHANCE OF LIGHT RAIN OR DRIZZLE TO THE AREA THURSDAY AND THURSDAY NIGHT. OTHERWISE DRY AND MILD WEATHER IS FORECAST THROUGH THE REMAINDER OF THE WEEK AND INTO THE UPCOMING WEEKEND. && .DISCUSSSION...AS OF 3:37 AM PDT WEDNESDAY...SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES ACROSS THE NORTHERN PORTION OF THE DISTRICT WITH SOME AREAS OF STRATO-CU OVER THE EAST BAY...THE SAN FRANCISCO PENINSULA...AND AROUND THE MONTEREY BAY AND NORTHERN MONTEREY COUNTY. THE SURFACE PRESSURE GRADIENTS ARE MODERATE TO STRONG ONSHORE WITH 2.4 MB FROM SFO-SAC...AND STRONG NORTHERLY WITH 5.1 MB FROM ACV TO SFO. GRADIENTS ARE FORECAST TO TIGHTEN AGAIN THIS AFTERNOON FOR ENHANCED ONSHORE SEA BREEZES. HIGH TEMPERATURES ARE EXPECTED TO BE SIMILAR TO THOSE ON TUESDAY WITH 60S AND 70S MOST AREAS...80S IN THE WARMEST INTERIOR SECTIONS. ON THURSDAY A WEAK UPPER LEVEL SYSTEM WILL APPROACH THE PACIFIC NORTHWEST AND BRING THE POSSIBILITY FOR SOME LIGHT PRECIP ACROSS MAINLY THE NORTHERN PORTIONS OF THE DISTRICT LATE THURSDAY THROUGH THURSDAY NIGHT. CONFIDENCE IS LOW AS THE MAIN MOISTURE FIELD IS FORECAST TO BE WELL TO THE NORTH. IF RAIN DOES FALL...AMOUNTS WILL ALMOST CERTAINLY BE UNDER A TENTH OF AN INCH. THE UPPER LOW ASSOCIATED WITH THE THURSDAY SYSTEM IS FORECAST TO MOVE INTO THE PACIFIC NORTHWEST BY LATE FRIDAY NIGHT AND THEN INTO THE NORTHERN GREAT BASIN BY SATURDAY NIGHT. THIS COULD TIGHTEN THE SURFACE PRESSURE GRADIENTS TO RESULT IN GUSTY NORTHERLY WINDS IN OUR HILLS ON SATURDAY NIGHT AND SUNDAY MORNING. WARMER WEATHER IS EXPECTED BY SUNDAY AND INTO NEXT WEEK AS DRY NORTHERLY FLOW DEVELOPS AND AN UPPER RIDGE BEGINS TO DEVELOP NEAR THE COAST. && .AVIATION...AS OF 4:20 AM PDT WEDNESDAY...MAINLY VFR CONDITIONS WILL PREVAIL AFTER 16Z. MODERATE CONFIDENCE. ANOTHER DAY OF STRONG WEST TO NORTHWEST WINDS ARE IN STORE FOR THE REGION THIS AFTERNOON INTO THE EARLY EVENING HOURS. OTHERWISE...A STORM SYSTEM IS FORECAST TO MOVE SOUTH TOWARD THE REGION EARLY THURSDAY MORNING...BRINGING POSSIBLE MVFR CIGS AT THE VERY END OF THE FORECAST PERIOD. VICINITY OF KSFO...PATCHY LOW CLOUDS SURROUND THE BAY...WITH SFO ON THE EDGE OF CLOUDS. SCT CLOUDS MAY IMPACT THE TERMINAL THROUGH THE 16Z HOUR...LOW CONFIDENCE. OTHERWISE...WEST WINDS WILL INCREASE SIGNIFICANTLY THIS AFTERNOON...WITH WIND GUSTS TO 35 KT PROBABLE. KSFO BRIDGE APPROACH...PATCHES OF SCT LOW CLOUDS MAY IMPACT THE APPROACH THROUGH THE 16Z HOUR PREVENTING VISUALS. MONTEREY BAY AREA TERMINALS...MVFR CIGS THROUGH AT LEAST THE 18Z HOUR...LOW CONFIDENCE. NUMERICAL GUIDANCE IS ALL OVER THE PLACE WITH CLEARING TIMES...FROM 15Z TO AN ALL DAY EVENT. THE MODELS ARE IN BETTER AGREEMENT THAT KSNS WILL SEE CLEARING BETWEEN 18Z AND 19Z...WHEREAS KMRY IS A BIT MORE PESSIMISTIC. THE HRRR AND LAMP INDICATE AN ALL DAY EVENT...SO WENT WITH A LATER CLEARING TIME OF 19Z. AGAIN LOW CONFIDENCE. && .MARINE...AS OF 02:40 AM PDT WEDNESDAY...MODERATE TO OCCASIONALLY STRONG WINDS WILL CONTINUE OVER THE WATERS THROUGH THIS EVENING AS SURFACE HIGH PRESSURE DOMINATES THE EASTERN PACIFIC. WINDS WILL SHIFT TO A WESTERLY DIRECTION ON THURSDAY MORNING AS A STORM SYSTEM CLIPS NORTHERN CA. OTHERWISE...HIGH PRESSURE WILL ONCE AGAIN SHIFT WINDS TO THE NORTHWEST AND CONTINUE INTO THE WEEKEND. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PT REYES 0-10 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PIGEON PT TO PT PINOS 0-10 NM SCA...PT ARENA TO PT REYES 10-60 NM SCA...PT REYES TO PIGEON PT 10-60 NM SCA...PIGEON PT TO PT PINOS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM SCA...ROUGH BAR ADVISORY FOR SF BAR UNTIL 3 PM SCA...SF BAY NORTH OF THE BAY BRIDGE FROM 1 PM SCA...SF BAY SOUTH OF THE BAY BRIDGE FROM 1 PM SCA...MONTEREY BAY FROM 1 PM && $$ PUBLIC FORECAST: SIMS AVIATION/MARINE: RILEY VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1103 PM EDT THU MAY 8 2014 .SYNOPSIS... A WARM FRONT WILL SLOWLY APPROACH THROUGH FRIDAY...MOVE INTO THE REGION FRIDAY NIGHT...THEN LIFT TO THE NORTH ON SATURDAY. A COLD FRONT WILL PASS SATURDAY NIGHT..FOLLOWED BY HIGH PRESSURE SUNDAY INTO MONDAY. A SERIES OF FRONTAL BOUNDARIES WILL THEN BRING UNSETTLED WEATHER INTO THE REST OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... STILL SEEING PATCHY FOG ACROSS LONG ISLAND AND SOUTHERN CT. STILL THINK WINDS ACROSS ERN SECTIONS WILL VEER MORE SE OVERNIGHT...WHICH COULD LEAD TO LOCALLY DENSE FOG THERE LATE TONIGHT. SHOWERS AND TSTMS HAVE DEVELOPED AS EXPECTED OVER CENTRAL NY STATE NEAR AN H8 WARM FRONT...IN RESPONSE TO MID LEVEL FORCING VIA AN H5 VORT MAX RIDING SE FROM ATOP THE UPPER RIDGE AXIS TO THE WEST...AND ALSO AS H8 THETA-E ADVECTION AND MOISTURE CONVERGENCE INCREASE. THESE SHOULD EXPAND SE-WARD INTO OUR CWA...FIRST INTO THE LOWER HUDSON VALLEY AND POSSIBLY NYC METRO JUST AFTER MIDNIGHT...AND THEN INTO THE REST OF THE AREA LATE ESPECIALLY ACROSS SOUTHERN CT AND LONG ISLAND PER LATEST HRRR/RAP. RAP FCST MUCAPE UP TO 500 J/KG ALSO SUGGESTS CONTINUED POTENTIAL FOR ELEVATED THUNDER AS THIS ACTIVITY EXPANDS SE-WARD. TEMPS SHOULD NOT FALL MUCH BELOW THEIR CURRENT VALUES...WITH LOWS 50-55. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FOR FRIDAY...THE AXIS OF THE UPPER LEVEL RIDGE MOVES ACROSS. PWATS DECREASE BY A FEW TENTHS OF AN INCH. AT THE SURFACE...A LACK OF PROGRESSION WILL BE APPARENT AS THE PARENT LOW DEEPENS A FEW MB IN TERMS OF CENTRAL PRESSURE AND WARM FRONT MAKES LITTLE PROGRESS NORTHEASTWARD. THE FLOW AT THE SURFACE REMAINS OUT OF THE SOUTHEAST AND INCREASES. THIS WILL MAKE FOR A PERSISTENT INVERSION AND MOISTURE UNDERNEATH THAT WILL REMAIN. THE MODEL QPF SHOWS THE AREA OF SHOWERS MOVING NORTHEAST OF THE REGION BY FRIDAY AFTERNOON WITH VERY LIGHT SHOWERS REMAINING BEHIND IT FOR THE REST OF THE DAY. THE POPS FOR THESE SHOWERS ARE STILL MAINLY CHANCE WITH OTHERWISE FOG AND DRIZZLE AS LOW LEVEL MOISTURE REMAINS BENEATH A PERSISTENT INVERSION. USED A 12Z NAM/GFS BLEND FOR MAX TEMPS WITH SOME MANUAL ADJUSTMENTS. THESE ARE A LITTLE WARMER THAN THE PREVIOUS DAY DUE TO TEMPS ALOFT INCREASING A FEW DEGREES BUT UNCERTAINTY IS THERE. WENT AT LEAST SEVERAL DEGREES BELOW THE GFS/NAM MOS GUIDANCE WHICH IS TOO OPTIMISTIC IN LIFTING CEILINGS DURING THE DAY. FOR FRIDAY NIGHT...A TRANSITION TO A MORE MERIDIONAL FLOW OCCURS WITH THE RIDGE MOVING OFFSHORE AND UPPER LEVEL SOUTHWEST TO NORTHEAST JET STREAK APPROACHING AHEAD OF THE UPPER LEVEL LOW IN ONTARIO. THE SOUTHEAST FLOW AT THE SURFACE CONTINUES THROUGH THE EVENING AND THEN BECOMES SOUTHWEST OVERNIGHT. THE WARM FRONT WILL BE WITHIN THE REGION BY SATURDAY MORNING. HOWEVER...EVEN THOUGH THIS MODELS ARE SHOWING THIS...THERE IS SOME HESITATION UPON TOTALLY COUNTING IN THIS SOLUTION BECAUSE OF THE RELATIVELY COOLER SEA SURFACE TEMPERATURES THAT MAY PROLONG THE PASSAGE OF THE WARM FRONT...PERHAPS MORE TOWARDS SATURDAY MORNING IN LATER MODEL RUNS. THE FORECAST HERE ESPECIALLY CONCERNING THE FRONTAL PASSAGE IS OF LOWER CONFIDENCE WITH CHANGES POSSIBLE WITH SUBSEQUENT FORECASTS. IN ANY CASE...THE LOW LEVEL MOISTURE UNDERNEATH THE INVERSION WILL REMAIN AND THE MODELS CONTINUE TO PORTRAY LITTLE QPF THROUGH THE NIGHT WITH SOME MORE ORGANIZED SHOWER ACTIVITY MOVING IN OVERNIGHT. THINKING THE LOW CLOUDS AND DRIZZLE WOULD PROBABLY CONTINUE GIVEN THESE FACTORS. ALSO THE CHANCE FOR SHOWERS WILL CONTINUE. IN ADDITION...INSTABILITY WILL INCREASE AS WELL ESPECIALLY AFTER THE WARM FRONT MOVES THROUGH. THEREFORE...STILL HAVE ISOLATED THUNDERSTORMS IN THE FORECAST FOR THIS TIME FRAME. && .LONG TERM /SATURDAY THROUGH THURSDAY/... UNSETTLED WEATHER ON TAP FOR MOST OF THE LONG TERM PERIOD. WARM FRONT LIFTS NORTH THROUGH THE REGION AS LOW PRES PASSES WELL NORTH OF THE REGION. SHOWERS WITH SCATTERED THUNDERSTORMS ARE LIKELY THROUGH THE DAY...TAPERING OFF AT NIGHT AS H5 TROUGH SWINGS THROUGH THE REGION AND THEN HIGH PRES BUILDS INTO THE REGION. INCREASING SW FLOW BEHIND THE WARM FRONT WILL PUSH TEMPS WELL INTO THE 70S... POSSIBLY APPROACHING 80 ACROSS THE URBANIZED AREAS OF NE NJ. TEMPS WILL BE SLIGHTLY COOLER NEAR THE COASTS. WITH HIGH PRES OVER THE AREA...IT APPEARS AS IF MOTHER`S DAY WILL BE NICEST DAY OF THE LONG TERM PERIOD WITH MOSTLY SUNNY SKIES AND TEMPS IN THE MID TO UPPER 70S...POSSIBLY AROUND 80 JUST WEST OF THE HUDSON RIVER. THE HIGH DEPARTS ON MONDAY...AND THEN A DEEP UPPER TROUGH DIGS INTO THE CENTRAL U.S. AND SLOWLY TRACKS EAST DURING THE WEEK. SEVERAL WEAK WAVES OF LOW PRES WILL DEVELOP AHEAD OF THIS TROUGH AND WILL APPROACH THE NORTHEAST DURING THIS TIME. AS A RESULT...WILL CARRY AT LEAST A CHANCE OF POPS FOR SHOWERS/TSTMS FROM MONDAY AFTERNOON THROUGH FRIDAY. MODEL GUIDANCE INDICATES THE TROUGH WILL SLIDE OFFSHORE ON FRIDAY. A MILD AIR MASS OVERSPREADS THE REGION WITH SW FLOW AHEAD OF THE TROUGH. HIGHS WILL GENERALLY TOP OFF IN THE MID-UPPER 70S...EXCEPT SLIGHTLY COOLER NEAR THE COASTS...THROUGH MUCH OF THE WEEK. AS THE TROUGH APPROACHES...HIGHS DROP INTO THE LOW-MID 70S TOWARDS THE END OF THE WEEK. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... A WARM FRONT WILL REMAIN SW OF THE REGION THRU THE TAF PERIOD. MAINLY IFR OR LOWER THRU THE TAF PERIOD. BR WILL REDUCE VSBY INTO FRI MRNG. A CHC OF -SHRA TNGT...ESPECIALLY AFT 05-06Z. THREAT OF SHOWERS DIMINISH NEAR 12-14Z. ISO TSTM ALSO POSSIBLE...BUT NOT HIGH ENOUGH COVERAGE FOR A MENTION IN TAFS. WINDS MOSTLY ESE UNDER 8KT OR LIGHT AND VARIABLE OVERNIGHT...SLOWLY VEERING SE ON FRI. SPEEDS STILL MAINLY BLW 10KT. .OUTLOOK FOR 00Z SAT THROUGH MONDAY... .SAT...BECOMING VFR IN THE AFTN WITH WINDS SHIFTING TO THE SW. CHC SHRA/TSTMS LATE. .SUN...EARLY MRNG SHRA/TSTMS POSSIBLE. OTHERWISE BECOMING VFR WITH NW FLOW. .MON-TUE...PERIODS OF MVFR OR LOWER WITH SW FLOW. && .MARINE... A WARM FRONT WILL SLOWLY APPROACH AND REMAIN TO THE S THROUGH FRI...AND THEN MOVE INTO AT LEAST A PORTION OF THE WATERS FRI NIGHT. CONFIDENCE IS HIGH ON OCEAN SEAS REMAINING SUB-SCA INTO MIDDAY SAT...BUT THEN INCREASING SW FLOW SHOULD PUSH OCEAN SEAS TO 4-6 FT LATE SAT AFTERNOON INTO SAT NIGHT. SEAS SHOULD THEN SUBSIDE ON SUNDAY. PERSISTENT SOUTHERLY FLOW WILL PUSH OCEAN SEAS UP TO SCA CRITERIA STARTING ON TUE...POSSIBLY LASTING THROUGH THE END OF THE UPCOMING WEEK. && .HYDROLOGY... GENERALLY...NO WIDESPREAD SIGNIFICANT PRECIP OF 1/2 INCH OR MORE IS EXPECTED THROUGH EARLY NEXT WEEK. FOR THE SHORT TERM THROUGH FRIDAY NIGHT...OUTSIDE OF ANY ISOLATED THUNDERSTORMS WHICH COULD RESULT IN LOCALLY HEAVY RAIN...TOTAL RAIN AMOUNTS WILL BE UP TO AROUND A QUARTER OF AN INCH. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JM/MPS NEAR TERM...GOODMAN/JM SHORT TERM...GOODMAN/JM LONG TERM...MPS AVIATION...JC MARINE...GOODMAN/JM/MPS HYDROLOGY...JM/MPS
AREA FORECAST DISCUSSION
NWS ALBANY NY
752 PM EDT THU MAY 8 2014 .SYNOPSIS... A WARM FRONT STRETCHING FROM THE THE LOWER GREAT LAKES TO THE MID ATLANTIC STATES WILL SLOWLY SHIFT NORTHEASTWARD TONIGHT. THE WARM FRONT WILL GRADUALLY MOVE ACROSS OUR REGION THROUGH FRIDAY...WITH SOME RAIN SHOWERS AND POSSIBLY A THUNDERSTORM. MUCH MILDER TEMPERATURES WILL BE USHERED IN ON SATURDAY ALONG WITH A CONTINUED THREAT FOR SHOWERS AND THUNDERSTORMS...AS A WEAK COLD FRONT CROSSES THE AREA. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... AS OF 745 PM EDT...MID LEVEL CLOUDS/MOISTURE SPILLING SOUTHEASTWARD OVER THE TOP OF AN UPPER LEVEL RIDGE AXIS POSITIONED OVER THE CENTRAL GREAT LAKES. THIS MID LEVEL MOISTURE WILL GRADUALLY OVERSPREAD THE REGION TONIGHT. THE BEST CHANCE FOR SHOWERS THIS EVENING WILL BE ACROSS THE ADIRONDACKS...AS SOME RADAR REFLECTIVITIES CAN BE SEEN UPSTREAM ON THE KTYX RADAR. THESE SHOWERS ARE BEING USHERED IN BY THE NORTHWEST FLOW ALOFT. LOW LEVELS ARE DRY ACROSS MUCH OF THE AREA...SO IT WILL TAKE TIME TO SATURATE. THUS WILL MENTION ONLY SLIGHT CHANCE TO CHANCE POPS THROUGH THE EVENING HOURS. AFTER MIDNIGHT...HI RES MODELS SUCH AS THE HRRR AND LOCAL WRF INDICATING CELLULAR SHOWERS DEVELOPING AND INCREASING IN COVERAGE ASSOCIATED WITH ELEVATED INSTABILITY. SO WILL RAISE POPS ESPECIALLY WEST OF ALBANY AND WILL MAINTAIN POSSIBLE ISOLATED THUNDER. ALSO...THE LOW LEVEL FLOW WILL START TO INCREASE FROM THE SOUTH...WHICH WILL DRAW STRATUS CLOUDS NORTHWARD LATE TONIGHT INTO FRIDAY MORNING. INCREASING CLOUDS WILL RESULT IN A RELATIVELY MILD NIGHT...WITH MAINLY LOWER TO MID 50S FOR LOWS EXCEPT UPPER 40S IN THE ADIRONDACKS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... UNTIL WE CAN GET THE FRONTAL BOUNDARIES THROUGH OUR REGION WHICH WILL NOT BE UNTIL EARLY NEXT WEEK...THERE WILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. AT THIS TIME IT LOOKS LIKE THE MOST ACTIVE DAY WILL BE SATURDAY AS MLMUCAPES RISE TO BTWN 500 AND 1000 J/KG SATURDAY AFTERNOON AS THE WARM FRONT AND THEN THE COLD FRONT APPROACH OUR REGION. SUNDAY LOOKS TO BE THE BETTER OF THE WEEKEND DAYS ALTHOUGH THERE STILL COULD BE A LINGERING SHOWER OR TWO. ON FRIDAY EXPECT THE COOLER OF THE WEEKEND DAYS AS THERE WILL BE A GOOD DEAL OF CLOUD COVER FROM LOWER LEVEL STRATUS WORKING NORTHWARD WHILE CONVECTION UPSTREAM WILL PROVIDE SOME HIGH CLOUDS. HIGHS ARE EXPECTED TO BE IN THE 60S. LOWS FRIDAY NIGHT WILL GENERALLY BE IN THE 50S. HIGHS ON SATURDAY AND SUNDAY ARE EXPECTED TO GENERALLY BE IN THE 70S WITH LOWS SATURDAY NIGHT IN THE 40S AND 50S. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THE LONG TERM PERIOD WILL BE CHARACTERIZED BY MILD TEMPERATURES AND UNSETTLED WEATHER AS A SERIES OF FRONTAL BOUNDARIES LINGER ACROSS THE REGION. AT THE START OF THE LONG TERM PERIOD...ZONAL FLOW WILL BE LINGERING ALOFT ACROSS THE REGION WITH AN INCREASINGLY AMPLIFIED PATTERN UPSTREAM...AS PIECES OF PACIFIC ENERGY CARVE OUT A DEEP UPPER-LEVEL TROUGH ACROSS THE CENTRAL PLAINS. AT THE SURFACE...WAVES OF LOW PRESSURE EJECTING OUT OF THE ROCKIES WILL EXTEND FRONTAL BOUNDARIES ACROSS THE GREAT LAKES REGION...AND EASTWARD INTO PORTIONS OF THE FORECAST AREA. THE LATEST LONG TERM GUIDANCE CONTINUES TO DEPICT SIGNIFICANT UNCERTAINTY REGARDING HOW THE SYNOPTIC PATTERN EVOLVES FOR NEXT WEEK. HOWEVER...THE AFOREMENTIONED FRONTAL BOUNDARIES WILL BE LINGERING ACROSS THE REGION...AND WITH LOW-LEVEL SOUTHERLY FLOW ADVECTING MOISTURE INTO THE REGION...WILL PROVIDE THE FOCUS FOR PRECIPITATION. GIVEN THE INCREASINGLY AMPLIFIED PATTERN...BELIEVE A SLOWER SOLUTION REGARDING THE EASTWARD TRACK OF THE CENTRAL PLAINS LOW WILL EVOLVE...MEANING THAT THE FOCUS FOR CONVECTION WILL LIKELY BE MORE OF A SCATTERED NATURE MONDAY AND TUESDAY. WITH DEWPOINTS RISING INTO THE UPPER 50S AND EVEN LOW 60S WITH SHOWALTER VALUES BETWEEN 0C AND -2C...ENOUGH SURFACE AND MID-LEVEL INSTABILITY SHOULD BE IN PLACE FOR SCATTERED SHOWERS AND THUNDERSTORMS. THE LOW PRESSURE SYSTEM SHOULD SLOWLY APPROACH FROM THE CENTRAL PLAINS BY MIDWEEK...PROVIDING HIGHER CHANCES FOR PRECIPITATION AS A COLD FRONT MOVES ACROSS THE REGION. HAVE GONE WITH CHANCE POPS BEGINNING MONDAY AND CONTINUING THROUGH THE REMAINDER OF THE LONG TERM DUE TO THE HIGH MODEL UNCERTAINTY. HIGH TEMPERATURES THROUGHOUT THE LONG TERM PERIOD WILL GENERALLY RANGE FROM NEAR 70 ACROSS THE HIGHER TERRAIN TO UPPER 70S IN VALLEY LOCATIONS...WITH THE POTENTIAL TO REACH INTO THE LOW TO MID 80S IN THE MID HUDSON VALLEY MONDAY AND TUESDAY. LOWS WILL GENERALLY RANGE FROM LOW 50S TO LOW 60S. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... MID LEVEL CLOUDS WILL OVERSPREAD THE KALB/KGFL/KPSF TERMINALS THIS EVENING...WITH A LOW PROBABILITY OF A FEW SHOWERS WITH THE MID LEVEL CLOUD DECK. KPOU SHOULD REMAIN WITH LOW STRATUS IN MVFR RANGE...ALTHOUGH SATELLITE IMAGERY AND LOCAL OBSERVATIONS INDICATE SOME BREAKS WILL BE POSSIBLE THIS EVENING. SHOWERS ARE EXPECTED TO INCREASE IN COVERAGE AFTER MIDNIGHT...MAINLY SCATTERED ACROSS THE TERMINALS BUT PERHAPS BECOMING NUMEROUS SLIGHTLY BEFORE OR TOWARDS DAYBREAK AS A WARM FRONT APPROACHES FROM THE SOUTH. WILL INDICATE VCSH OR PREVAILING -SHRA LATE TONIGHT THROUGH FRIDAY MORNING. CIGS ARE ALSO EXPECTED TO DETERIORATE TO MVFR THEN POSSIBLE IFR AT KPOU/KPSF LATE TONIGHT INTO FRIDAY MORNING...AS THE LOW LEVEL FLOW BECOME SOUTHERLY WITH LOW STRATUS CLOUDS EXPECTED TO MIGRATE NORTHWARD FROM COASTAL AREAS. A BREAK IN THE SHOWERS IS POSSIBLE FRIDAY AFTERNOON...AND CIGS SHOULD RISE SOMEWHAT. HOWEVER...STILL OVC CIGS IN MVFR RANGE EXPECTED THROUGH 00Z SATURDAY. SURFACE WINDS WILL BE LIGHT AND VARIABLE TONIGHT...BECOMING SOUTHEAST AROUND 5-10 KT FRIDAY MORNING. OUTLOOK... FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. SATURDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA. SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. SUNDAY TO SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. MONDAY TO TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. && .FIRE WEATHER... A WARM FRONT STRETCHING FROM THE THE LOWER GREAT LAKES TO THE MID ATLANTIC STATES WILL SLOWLY SHIFT NORTHEASTWARD THIS EVENING. THE WARM FRONT WILL GRADUALLY MOVE ACROSS THE REGION TONIGHT THROUGH FRIDAY WITH SOME ADDITIONAL RAIN SHOWERS AND POSSIBLY A THUNDERSTORM. MUCH MILDER TEMPERATURES WILL BE USHERED IN ON SATURDAY ALONG WITH A CONTINUED THREAT FOR SHOWERS AND THUNDERSTORMS...AS A WEAK COLD FRONT CROSSES THE AREA. RELATIVE HUMIDITIES WILL RECOVER TO BETWEEN 80 AND 100 PERCENT TONIGHT...ONLY FALL TO 60 TO 80 PERCENT ON FRIDAY...RECOVER TO 90 TO 100 PERCENT ON FRIDAY NIGHT...AND FALL TO 45 TO 55 PERCENT ON SATURDAY. WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT. SOUTHEAST AT 5 TO 10 MPH ON FRIDAY. SOUTHEAST TO SOUTHWEST AT 5 TO 10 MPH ON FRIDAY NIGHT AND SOUTHWEST AT 5 TO 10 MPH ON SATURDAY. && .HYDROLOGY... NO WIDESPREAD HYDROLOGIC PROBLEMS ARE ANTICIPATED DURING THE NEXT FIVE DAYS. A WARM FRONT WILL SLOWLY APPROACH OUR REGION FROM THE SOUTHERN GREAT LAKES AND MID ATLANTIC REGION. AS THE FRONT STARTS TO LIFT FURTHER NORTHEASTWARD...THE CHANCE FOR RAIN SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE ENTIRE REGION LATER TONIGHT INTO FRIDAY. THERE WILL BE A CONTINUED THREAT FOR SHOWERS AND SCATTERED THUNDERSTORMS INTO SATURDAY...AS A WEAK COLD FRONT CROSSES THE REGION. BEHIND THE FRONT...DRY WEATHER WILL RETURN FOR SUNDAY. RAINFALL WILL BE VARIABLE ACROSS THE REGION DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS. OVERALL...MOST LOCATIONS LOOK TO RECEIVE BETWEEN ONE HALF INCH AND ONE INCH OF RAINFALL THROUGH SUNDAY NIGHT...WITH THE HEAVIER AMOUNTS WHERE LOCALIZED SCATTERED THUNDERSTORMS OCCUR. WHILE THERE MAY BE SOME MINOR RISES ON RIVERS AND STREAMS...ALL WATERWAYS ARE EXPECTED TO STAY WITHIN THEIR BANKS...AND NO FLOODING IS ANTICIPATED AT THIS TIME. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...11/JPV NEAR TERM...11/JPV SHORT TERM...11 LONG TERM...IRL AVIATION...JPV FIRE WEATHER...11 HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
638 PM EDT WED MAY 7 2014 .SYNOPSIS... HIGH PRESSURE WILL SLOWLY MOVE OFFSHORE THROUGH TONIGHT. A WARM FRONT OVER THE OHIO VALLEY AND CAROLINAS WILL SLOWLY MOVE NORTHEAST AND PASS THROUGH THE FORECAST AREA EARLY SATURDAY. A WEAK COLD FRONT IS FORECAST TO CROSS THE AREA LATE SATURDAY OR EARLY SUNDAY AND THEN STALL JUST SOUTH OF THE AREA. ANOTHER WARM FRONT IS FORECAST TO CROSS THE AREA MONDAY OR TUESDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 445 PM ESTF UPDATED AT 630 PM: TEMPS TRIMMED SEVERAL DEGREES FURTHER THIS EVENING. NO THUNDER THRU 06Z AND PLAYED DOWN THUNDER IN THE WORDING TIL LATE. BEST POTENTIAL FOR ANY THUNDER AND HEAVY RAIN SHOWERS VERY LATE TONIGHT IS E CENTRAL AND SE PA AND S 1/2 NJ..ALONG AND S OF KABE-KBLM. THAT IS ALSO THE 18Z GFS SOLN AND I AM THINKING THAT HAS THE BEST CHANCE OF VERIFICATION WITH PROXIMITY TO THE UNSTABLE AIR. IN OTHER WORDS...REDEVELOPING CONVECTIVE CLUSTERS ARE USUALLY TOWARD THE GREATEST INSTABILITY. DIFFERENTIAL WAA IN A NW FLOW ALOFT SITUATION WITH SHORT WAVES ASSISTING PERIODS OF LIFT. USING SPC WRF...HRRR AND RAP TO ADJUST POPS AND A BEST MATCH TO THE GOING REALITY THIS EVENING. BASED ON OBSERVED TRENDS AT 830 PM WILL PROBABLY SHIFT HIGHEST POPS IN THE 06Z-15Z TIME FRAME FURTHER SOUTH AND THE WORDING AS POSSIBLY HEAVY SHOWERS AND ISOLATED TSTMS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... A CLOUDY/SHOWERY MORNING IS EXPECTED ACROSS THE AREA WITH A BIG RANGE IN TEMPERATURES ACROSS THE REGION DURING THE AFTN. HAVE ALREADY CUT POPS TO 12 PCT MOST OF THE AREA 16Z-22Z TIME FRAME...IN OTHER WORDS...I THINK ITS A RAINFREE AFTERNOON. HIGHS OVER MARYLANDS EASTERN SHORE MAY REACH THE MID/UPPER 70S WHILE FURTHER N OVER NRN NJ AND THE SRN POCONOS...THE HIGHS WILL ONLY RISE MAYBE NEAR 60. SCT TSTMS ARE POSSIBLE THU AS WELL...BUT CAPES ARE RATHER LOW...SO WE WILL JUST KEEP WORDING SCT FOR NOW. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... A WARM FRONT WILL BE WORKING ITS WAY NORTHWARD SLOWLY THU NIGHT INTO FRI. PRECIP CHANCES WILL OCCUR ALG THE FRONT AND END (OR DECREASE SUBSTANTIALLY) BEHIND IT. THE GFS SEEMS ANOMALOUSLY WET COMPARED TO THE OTHER GUID EARLY FRI AND WAS IGNORED. THE HIGHEST PRECIP CHCS ON THRU FRI WILL BE OVER NRN AREAS WHERE THE FRONT WILL TAKE THE LONGEST TIME TO CLEAR. FOR MANY AREAS, THE BULK OF FRI CUD BE DRY. FRI NIGHT LOOKS CLOUDY WITH CHC POPS AS THE AREA REMAINS IN THE WARM SECTOR, BUT A CDFNT IS APPROACHING FROM THE W. POPS WILL CONTINUE TO INCREASE ON SAT AS THE AFOREMENTIONED CDFNT GETS CLOSER AND CROSSES THE REGION LATER SAT. PRECIP SHUD DECREASE DURG SAT EVE AFTER FROPA. HIGH PRES THEN BUILDS BACK IN FOR SAT NIGHT INTO SUN. THEN THERE IS CONSIDERABLE MDL DISAGREEMENT FOR EARLY NEXT WEEK. THE GFS IS QUITE A BIT FASTER WITH THE NEXT LOW/CDFNT AND ASSOCD PRECIP THAN THE ECMWF. THE GFS HAS SOME DIURNAL PRECIP ON MON BUT A BETTER SHOT WITH THE CDFNT ON TUE. THE ECMWF IS ESSENTIALLY DRY THRU THE PD. THERE IS THE CHANCE OF SOME DIURNAL SHWRS MON BUT THEN NOTHING BEFORE THE CDFNT, WHICH IS AT LEAST A DAY BEHIND THE GFS. SO, IF THE ECMWF IS CORRECT, EARLY NEXT WEEK WOULD BE DRIER THAN THE GFS IS INDICATING, BUT THERE IS STILL A WEEK TO SORT THINGS OUT. BY EARLY NEXT WEEK, THE MDLS BUILD AN UPR RIDGE BACK OVER THE AREA. TEMPS WILL GENLY BE ABV NRML ON FRI BEHIND THE WMFNT AND NR OR PSBLY BELOW NRML AHEAD OF THE FRONT (ALSO DEPENDENT ON CLOUDS/PRECIP). THEN MOST OF THE REST OF THE UPCOMING WEEK WILL FEATURE ABOVE NRML TEMPS WITH HIGHS NR 80 THU THE WKND INTO ERLY NEXT WEEK. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TONIGHT...BKN-OVC CIGS AOA 5000 FT WITH A MVFR CIG POSSIBLY DEVELOPING AFTER 06Z. SCT SHOWERS...MOSTLY KABE SOUTH. THUNDER POTENTIAL IN MORE ORGANIZED HEAVY SHOWERS LIKELY AFTER 06Z WHERE IFR CONDS MAY DEVELOP IN SHOWERS/STRATUS...PROBABLY FOR MANY TAF SITES. LIGHT WIND. THURSDAY...MVFR CIGS MAY BREAK TO MAINLY VFR CIGS AOA 3000 FT THU AFTN. SHOWERS MAINLY IN THE MORNING MAYBE WITH ISOLATED TSTMS. LIGHT WIND TRENDING NE. OUTLOOK... THU NIGHT...MVFR CONDITIONS AT TIMES DUE TO SHWRS AND TSTMS EARLY (MAINLY N)...AS WELL AS LOWER CLOUDS AND FOG AS WARM FRONT MOVES NWD THRU THE REGION. MDT CONFIDENCE. FRI AND FRI NIGHT...PRIMARILY VFR DURING THE DAY AND SOME MVFR CONDS AT NIGHT. MDT-HIGH CONFIDENCE. SAT...OCCASIONAL MVFR TO BRIEFLY IFR CONDITIONS IN SCATTERED SHOWERS AND THUNDERSTORMS. MDT CONFIDENCE SUN-SUN NIGHT...VFR. HIGH CONFIDENCE. MON...MAINLY VFR. PSBL AFTN SHWRS/TSTMS THAT CUD LWR VSBYS/CIGS. LOW-MDT CONFIDENCE. && .MARINE... CONDITIONS ON THE WATERS WILL REMAIN BELOW SMALL CRAFT CRITERIA THROUGH THURSDAY. THERE MAY BE A FEW SCT TSTMS LATE TONIGHT AND THURSDAY. WINDS LIGHT TRENDING EASTERLY WITH TIME THRU THURSDAY. OUTLOOK... SUB SCA CONDS ARE EXPECTED THU NIGHT THRU FRI. FOG MAY BE THE GREATER CONCERN, ESPECIALLY THURSDAY NIGHT. WITH A VEERING OF WINDS TOWARD THE SOUTH, THE CONCERN MAY MOVE OUT OF OUR AREA BY FRIDAY NIGHT. SEAS INCREASE OVER THE WEEKEND, BUT WE ARE PLAYING IT A BIT MORE CONSERVATIVE DUE TO SWLY FLOW...BUT THERE IS SOME SCA POTENTIAL THERE. A GREATER SCA POTENTIAL OCCURS EARLY NEXT WEEK IN ADVANCE OF THE NEXT SYS, BUT THERE ARE STILL SOME TIMING ISSUES WRT TO THIS SYS. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...NIERENBERG NEAR TERM...DRAG/O`HARA 638 SHORT TERM...DRAG/O`HARA 638 LONG TERM...NIERENBERG AVIATION...DRAG/NIERENBERG/O`HARA 638 MARINE...DRAG/NIERENBERG/O`HARA 638
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
502 PM EDT WED MAY 7 2014 .SYNOPSIS... HIGH PRESSURE WILL SLOWLY MOVE OFFSHORE THROUGH TONIGHT. A WARM FRONT OVER THE OHIO VALLEY AND CAROLINAS WILL SLOWLY MOVE NORTHEAST AND PASS THROUGH THE FORECAST AREA AROUND FRIDAY. A WEAK COLD FRONT IS FORECAST TO CROSS THE AREA LATE SATURDAY OR EARLY SUNDAY AND THEN STALL JUST SOUTH OF THE AREA. ANOTHER WARM FRONT IS FORECAST TO CROSS THE AREA MONDAY OR TUESDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 630 PM ESTF SENT 445PM: TEMPS SIGNIFICANTLY COOLER THIS EVE. NO THUNDER THRU 06Z AND PLAYED DOWN THUNDER IN THE WORDING LATE. BEST POTENTIAL FOR ANY THUNDER AND HEAVY RAIN SHOWERS VERY LATE TONIGHT IS E CENTRAL AND SE PA AND S 1/2 NJ..ALONG AND S OF KABE-KBLM. DIFFERENTIAL WAA IN A NW FLOW ALOFT SITUATION WITH SHORT WAVES ASSISTING PERIODS OF LIFT. USING SPC WRF...HRRR AND RAP TO ADJUST POPS AND A BEST MATCH TO THE GOING REALITY. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... THE WARM FRONT WILL BE LIFTING ACROSS THE AREA THURSDAY. A CLOUDY/SHOWERY DAY IS EXPECTED ACROSS THE AREA WITH A BIG RANGE IN TEMPERATURES ACROSS THE REGION. HIGHS OVER THE DELMARVA MAY REACH THE MID/UPPER 70S WHILE FURTHER NE OVER NRN NJ AND THE SRN POCONOS...THE HIGHS WILL ONLY RISE INTO THE LOW 60S. SCT TSTMS ARE POSSIBLE THU AS WELL...BUT CAPES ARE RATHER LOW...SO WE WILL JUST KEEP WORDING SCT FOR NOW. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... A WARM FRONT WILL BE WORKING ITS WAY NORTHWARD SLOWLY THU NIGHT INTO FRI. PRECIP CHANCES WILL OCCUR ALG THE FRONT AND END (OR DECREASE SUBSTANTIALLY) BEHIND IT. THE GFS SEEMS ANOMALOUSLY WET COMPARED TO THE OTHER GUID EARLY FRI AND WAS IGNORED. THE HIGHEST PRECIP CHCS ON THRU FRI WILL BE OVER NRN AREAS WHERE THE FRONT WILL TAKE THE LONGEST TIME TO CLEAR. FOR MANY AREAS, THE BULK OF FRI CUD BE DRY. FRI NIGHT LOOKS CLOUDY WITH CHC POPS AS THE AREA REMAINS IN THE WARM SECTOR, BUT A CDFNT IS APPROACHING FROM THE W. POPS WILL CONTINUE TO INCREASE ON SAT AS THE AFOREMENTIONED CDFNT GETS CLOSER AND CROSSES THE REGION LATER SAT. PRECIP SHUD DECREASE DURG SAT EVE AFTER FROPA. HIGH PRES THEN BUILDS BACK IN FOR SAT NIGHT INTO SUN. THEN THERE IS CONSIDERABLE MDL DISAGREEMENT FOR EARLY NEXT WEEK. THE GFS IS QUITE A BIT FASTER WITH THE NEXT LOW/CDFNT AND ASSOCD PRECIP THAN THE ECMWF. THE GFS HAS SOME DIURNAL PRECIP ON MON BUT A BETTER SHOT WITH THE CDFNT ON TUE. THE ECMWF IS ESSENTIALLY DRY THRU THE PD. THERE IS THE CHANCE OF SOME DIURNAL SHWRS MON BUT THEN NOTHING BEFORE THE CDFNT, WHICH IS AT LEAST A DAY BEHIND THE GFS. SO, IF THE ECMWF IS CORRECT, EARLY NEXT WEEK WOULD BE DRIER THAN THE GFS IS INDICATING, BUT THERE IS STILL A WEEK TO SORT THINGS OUT. BY EARLY NEXT WEEK, THE MDLS BUILD AN UPR RIDGE BACK OVER THE AREA. TEMPS WILL GENLY BE ABV NRML ON FRI BEHIND THE WMFNT AND NR OR PSBLY BELOW NRML AHEAD OF THE FRONT (ALSO DEPENDENT ON CLOUDS/PRECIP). THEN MOST OF THE REST OF THE UPCOMING WEEK WILL FEATURE ABOVE NRML TEMPS WITH HIGHS NR 80 THU THE WKND INTO ERLY NEXT WEEK. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TONIGHT...BKN-OVC CIGS AOA 5000 FT WITH A MVFR CIG POSSIBLY DEVELOPING AFTER 06Z. SCT SHOWERS...MOSTLY KABE SOUTH. THUNDER POTENTIAL IN MORE ORGANIZED HEAVY SHOWERS POSSIBLE AFTER 06Z WHERE IFR CONDS MAY DEVELOP IN SHOWERS/STRATUS. LIGHT WIND. THURSDAY...MVFR CIGS MAY BREAK TO MAINLY VFR CIGS AOA 3000 FT THU AFTN. SHOWERS MAINLY IN THE MORNING MAYBE WITH ISOLATED TSTMS. LIGHT WIND TRENDING NE. OUTLOOK... THU NIGHT...MVFR CONDITIONS AT TIMES DUE TO SHWRS AND TSTMS EARLY (MAINLY N)...AS WELL AS LOWER CLOUDS AND FOG AS WARM FRONT MOVES NWD THRU THE REGION. MDT CONFIDENCE. FRI AND FRI NIGHT...PRIMARILY VFR DURING THE DAY AND SOME MVFR CONDS AT NIGHT. MDT-HIGH CONFIDENCE. SAT...OCCASIONAL MVFR TO BRIEFLY IFR CONDITIONS IN SCATTERED SHOWERS AND THUNDERSTORMS. MDT CONFIDENCE SUN-SUN NIGHT...VFR. HIGH CONFIDENCE. MON...MAINLY VFR. PSBL AFTN SHWRS/TSTMS THAT CUD LWR VSBYS/CIGS. LOW-MDT CONFIDENCE. && .MARINE... CONDITIONS ON THE WATERS WILL REMAIN BELOW SMALL CRAFT CRITERIA THROUGH THURSDAY. THERE MAY BE A FEW SCT TSTMS LATE TONIGHT AND THURSDAY. WINDS LIGHT TRENDING EASTERLY WITH TIME THRU THURSDAY. OUTLOOK... SUB SCA CONDS ARE EXPECTED THU NIGHT THRU FRI. FOG MAY BE THE GREATER CONCERN, ESPECIALLY THURSDAY NIGHT. WITH A VEERING OF WINDS TOWARD THE SOUTH, THE CONCERN MAY MOVE OUT OF OUR AREA BY FRIDAY NIGHT. SEAS INCREASE OVER THE WEEKEND, BUT WE ARE PLAYING IT A BIT MORE CONSERVATIVE DUE TO SWLY FLOW...BUT THERE IS SOME SCA POTENTIAL THERE. A GREATER SCA POTENTIAL OCCURS EARLY NEXT WEEK IN ADVANCE OF THE NEXT SYS, BUT THERE ARE STILL SOME TIMING ISSUES WRT TO THIS SYS. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...NIERENBERG NEAR TERM...DRAG/O`HARA 502 SHORT TERM...O`HARA 502 LONG TERM...NIERENBERG AVIATION...DRAG/NIERENBERG/O`HARA 502 MARINE...DRAG/NIERENBERG/O`HARA 502
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1042 AM EDT WED MAY 7 2014 .SYNOPSIS... A HIGH PRESSURE RIDGE OVER THE FORECAST AREA WILL EASE OFFSHORE LATER TODAY. A WARM FRONT OVER THE OHIO VALLEY AND CAROLINAS WILL SLOWLY MOVE NORTHEAST AND PASS THROUGH THE FORECAST AREA AROUND FRIDAY. A WEAK COLD FRONT IS FORECAST TO CROSS THE AREA LATE SATURDAY OR EARLY SUNDAY AND THEN STALL JUST SOUTH OF THE AREA. THIS FRONT IS THEN EXPECTED TO REVERSE COURSE AND START MOVING NORTHWARD THROUGH OUR REGION AGAIN ON MONDAY AND TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A RIDGE OF HIGH PRESSURE ACROSS THE REGION WILL WEAKEN TODAY WHILE A WARM FRONT MOVES NORTH/EAST FROM THE OHIO VALLEY. AN AREA OF TSTMS ASSOC WITH A SHORT WAVE MOVING SE ACROSS WRN MD/S CENT PA WILL CONTINUE TO MOVE SE AS PER THE RECENT HRRR WHICH HAS A GOOD HANDLE ON IT. THESE SHOWERS WILL ARRIVE ACROSS THE DELMARVA AREAS EARLY THIS AFTERNOON...SO POPS ACROSS THESE AREAS HAVE BEEN INCREASED ON THE MOST RECENT ESTF. WE USED A BLEND OF MAV/MET MOS AND MOS GUIDE FOR DAYTIME HIGHS. WITH THE THICKENING CLOUD COVER DURING THE DAY, HIGHS ARE FORECAST TO BE A COUPLE OF DEGREES BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... AS THE AFOREMENTIONED HIGH PRESSURE CONTINUES TO RECEDE AND SHIFT EASTWARD OFF THE COAST, THE WARM FRONT WILL PUSH CLOSER TO THE AREA OVERNIGHT. A COUPLE OF SHORT WAVE/VORT MAXES ARE FORECAST TO TRAVERSE THE AREA OVERNIGHT, WHICH COMBINED WITH THE AVAILABLE MOISTURE IS EXPECTED TO ENHANCE SHOWER ACTIVITY ACROSS THE AREA. THERE IS NOT MUCH INSTABILITY, BUT WE WILL KEEP THE CHANCE OF THUNDERSTORMS IN THE FORECAST FOR NOW AS THERE IS SOME WEAK ELEVATED INSTABILITY. ALSO, TOTAL TOTALS INCH UP TO THE MID-UPPER 40S AND K-INDEX VALUES CLIMB INTO THE MID-UPPER 20S. WE USED A BLEND OF MAV/MET MOS AND MOS GUIDE FOR OVERNIGHT LOWS WHICH KEEPS EVERYONE WITHIN A DEGREE OR TWO OF NORMAL. && .LONG TERM /THURSDAY THROUGH TUESDAY/... NEITHER DOMESTIC MODEL`S INITIALIZATION IN THE MIDWEST LOOKED THAT GRAND AND THE GFS IS ALREADY WAY TOO HOT WITH ITS QPF FIELDS IN ITS FIRST SIX HOURS. IF ANYTHING, THE GENERAL MODELING CONSENSUS HAS A SOUTHWARD BIAS ON ONGOING MIDWEST CONVECTION. FORECAST CONFIDENCE IS REDUCED BY WHAT LOOKS LIKE FEEDBACK VORT MAXES, ESPECIALLY ON THE GFS. WHETHER REALISTIC OR NOT, A DP/DT ON THEM THU AND FRI SHOW VERY LITTLE RUN TO RUN CONTINUITY. ADJUSTMENTS TO THE LONG TERM WILL BE A BLEND OF NON-GFS MODELS WITH WPC GUIDANCE AND CONTINUITY. GREATEST EMPHASIS ON POPS REMAINS EARLY THURSDAY AND SATURDAY. WE PREFER THE MORE NORTHERN MODELING SOLUTIONS TO START OUR HIGHEST PCPN CHANCES ON THURSDAY MORNING. AS THE MORNING AND AFTERNOON PROGRESSES, PCPN CHANCES ARE EXPECTED TO BE LESS AS THE TRIGGERING SHORT WAVE MOVES OFFSHORE AND FORECAST MOISTURE ABOVE 925MB DECREASES. FORECAST UNCERTAINTY WITH THE ONSHORE FLOW IS HOW MUCH CLEARING WILL OCCUR AS THERE WILL BE AN INVERSION. ONE WOULD THINK THAT THE MAY SUN WILL HAVE SOME EFFECT. LEAST CONFIDENCE THOUGH IS NORTHEAST WITH GREATEST CONFIDENCE OVER DELMARVA. WIDE RANGE IN MAX TEMPS ACROSS OUR CWA REFLECT THIS. WE DIDN`T CHANGE THEM MUCH FROM CONTINUITY. ANOTHER MID LEVEL WAA SURGE (SOME FGEN AND QVEC FORCING SHOWING UP IN THE FIELDS ALSO) IS FORECAST FOR THURSDAY NIGHT. THIS ONE HAS MORE ELEVATED CONVECTIVE INSTABILITY THAN TONIGHT, BUT RIGHT NOW IS NOT COUPLED WITH AN ATTENDANT SHORT WAVE. OVERALL WEAK FLOW ALOFT AND NO PREDICTED LLJ. POPS THUS WERE KEPT BLO LIKELY LEVELS. IN ADDITION, THE CONTINUING ONSHORE FLOW WITH DEW POINT TEMPERATURES RISING ABOVE THE WATER TEMPERATURES INCREASES THE CHANCES FOR MARINE FOG ADVECTING INLAND. WHILE POSSIBLE, WE MIGHT ALSO HAVE SOME DRIZZLE WHICH WOULD MAKE FOR AN OXYMORONIC METEOROLOGICAL PAIRING, DRIZZLE CAUSED BY THE STABLE TRAPPING OF MOISTURE BELOW THE FRONTAL INVERSION, BUT AN UNSTABLE AIR MASS ABOVE THE INVERSION CAPABLE OF TRIGGERING THUNDERSTORMS. ON FRIDAY, THE WARM FRONT IS PREDICTED TO MAKE MORE NORTHWARD PROGRESS AS THE 500MB RIDGE AXIS EASES TO THE EAST. RELATIVELY DRY AIR ONCE AGAIN IS PREDICTED TO PASS OVER OUR CWA, SO THE PCPN CHANCES ONCE AGAIN SHOULD DECREASE DURING THE MIDDLE OF THE DAY WITH A SLIGHT UPTICK IN CHANCES NORTHWEST LATE IN THE DAY. WHILE ON THURSDAY WE MIGHT BE TOO WARM WITH MAX TEMPS, FRIDAY WE MIGHT BE TOO LOW, ESPECIALLY DELMARVA. FRIDAY NIGHT WE INCREASE THE POPS AGAIN AS THE COLD FRONT APPROACHES. SATURDAY POTENTIALLY COULD HAVE STRONG THUNDERSTORMS AS THE COLD FRONT COMES CLOSER. THE FORECAST WIND FIELD (LLJ AND JET ALF COUPLET) SURE DO LOOK BETTER AND THE EFFECTIVE PREDICTED BULK SHEAR IS MORE ROBUST. THE LACK OF A LEE SIDE TROF FORMING BACKING THE WINDS FURTHER TO THE SOUTH WOULD BE THE LIMITING FACTOR TO COVERAGE. DONT BELIEVE CLOUDS OR TOO LOW TEMPS WILL BE THE WET BLANKET. FOR NOW, WE MAINTAIN INCREASINGLY HIGHER POPS WITH GREATEST CHANCES WEST. WE ARE DEEP IN THE SW FLOW BY SATURDAY, SO WE ARE PRETTY CONFIDENT WE WILL REACH OUR FORECAST MAX TEMPS. THE LATEST ECMWF AND GFS RUNS ARE MORE OPTIMISTIC ABOUT THE COLD FRONT CLEARING OUR CWA ON MOTHER`S DAY AND WE LOWERED POPS AND REMOVED THE MENTION OF THUNDER. THE AIR MASS BEHIND THE COLD FRONT IS NOT THAT MUCH COOLER, NOT MUCH OF A DROP OFF IN TEMPS. STILL ABOVE NORMAL. WHETHER ITS THE AFOREMENTIONED FRONT BACKING TO THE NORTH AGAIN, OR ANOTHER FRONT APPROACHING FROM THE WEST. BOTH INCREASE OUR CHANCES FOR SHOWERS AND THUNDERSTORMS ON MONDAY AND TUESDAY. TEMPERATURES THOUGH STILL LOOK PRETTY, PRETTY WARM FOR THE START OF THE WORK WEEK. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS ARE EXPECTED TO REMAIN ACROSS THE TAF SITES FOR TODAY INTO THE EARLY PART OF THE EVENING, ALTHOUGH CLOUDS WILL BE THICKENING AND LOWERING THROUGH THE DAY. THERE COULD BE SOME SCATTERED SHOWERS LATE IN THE DAY, BUT THEY ARE NOT EXPECTED TO REDUCE CIGS/VSBYS. AS WE GO INTO LATE EVENING HOURS AND INTO THE OVERNIGHT HOURS, CONDITIONS ARE EXPECTED TO LOWER TO MVFR, AND EVENTUALLY IFR AS AN AREA OF SHOWERS MOVES INTO THE AREA. THERE IS A SMALL CHANCE OF THUNDERSTORMS, BUT WE WILL KEEP THEM OUT OF THE TAFS FOR NOW SINCE CONFIDENCE IS NOT VERY HIGH ON THEM ACTUALLY OCCURRING. LIGHT WINDS EARLY THIS MORNING, MOSTLY FROM THE NORTHEAST, WILL BECOME MORE SOUTHEASTERLY OR SOUTHERLY THIS AFTERNOON. WINDS WILL SWITCH BACK TO THE SOUTHEAST THEN EAST LATER THIS EVENING AND OVERNIGHT. OUTLOOK... THURSDAY AND THURSDAY NIGHT...MVFR CONDITIONS AT TIMES DUE TO SHOWERS AND THUNDERSTORMS AS WELL AS LOWER CLOUDS AND FOG AT NIGHT. FRIDAY AND FRIDAY NIGHT...PRIMARILY VFR DURING THE DAY AND SOME MVFR CONDITIONS AT NIGHT. SATURDAY...OCCASIONALLY MVFR TO BRIEFLY IFR CONDITIONS IN SCATTERED SHOWERS AND THUNDERSTORMS. SUNDAY...PREDOMINATELY VFR. && .MARINE... SUB-ADVISORY CONDITIONS WILL PREVAIL ACROSS THE WATERS THROUGH TODAY AND TONIGHT AS HIGH PRESSURE THAT HAS BEEN OVER THE AREA RECEDES AND LIFTS TO THE NORTHEAST, ALTHOUGH WINDS MAY PERIODICALLY GUST AROUND 15-20 KNOTS. OUTLOOK... SUB SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED FOR THE NEXT SEVERAL DAYS. FOG MAY BE THE GREATER CONCERN, ESPECIALLY THURSDAY NIGHT WHEN THE SREF IS INDICATING A FOG BANK FORMING OVER OUR ATLANTIC WATERS. WITH A VEERING OF WINDS TOWARD THE SOUTH, THE CONCERN MAY MOVE OUT OF OUR AREA BY FRIDAY NIGHT. WE CONTINUE TO BE MORE CONSERVATIVE THAN WAVE WATCH SEAS WITH THE SW FLOW PRECEDING THE NEXT COLD FRONT ON THE WEEKEND AND THE POST FRONTAL SFC WINDS ARE RELATIVELY WEAK. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...AMC/GIGI NEAR TERM...ROBERTSON/PO SHORT TERM...ROBERTSON LONG TERM...GIGI AVIATION...AMC/GIGI/ROBERTSON MARINE...AMC/GIGI/ROBERTSON
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
209 PM EDT WED MAY 7 2014 .SYNOPSIS... UPPER-LEVEL RIDGING AS WELL AS SURFACE HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH FRIDAY. THE RIDGE WILL WEAKEN SATURDAY AS A DISSIPATING FRONTAL SYSTEM MOVES INTO THE AREA. && .NEAR TERM /THROUGH TONIGHT/... THE PRESSURE RIDGE EXTENDING INTO THE FORECAST AREA FROM THE ATLANTIC WILL MAINTAIN THE DRY CONDITIONS. SATELLITE TRENDS SUPPORT MOSTLY CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS CONSISTENT. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... SURFACE HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE FORECAST AREA FROM THE ATLANTIC THROUGH FRIDAY NIGHT. ALOFT...THE MODELS INDICATE THE RIDGE WILL SHIFT OFF THE COAST FRIDAY. THE GUIDANCE TEMPERATURES WERE CONSISTENT...BUT THE HIGH TEMPERATURE GUIDANCE MAY BE A LITTLE TOO COOL BASED ON RECENT VERIFICATION...DRY CONDITIONS...AND UPPER RIDGE. IT MAY BE SLIGHTLY COOLER FRIDAY AS SOME MID- AND HIGH-LEVEL CLOUDS MAY SPREAD INTO THE AREA IN THE SOUTHWESTERLY FLOW. && .LONG TERM /SATURDAY THROUGH TUESDAY/... THE MODELS SHOW SOME MOISTURE ASSOCIATED WITH THE REMNANTS OF A FRONT IN THE FORECAST AREA EARLY IN THE MEDIUM-RANGE PERIOD. A COLD FRONT MAY MOVE INTO THE AREA LATE IN THE PERIOD. THE GFS... ECMWF...AND EKD MOS HAVE BEEN TRENDING LOWER WITH THE POPS. THE LATEST GUIDANCE HAS POPS OF 20 TO 30 PERCENT. THE PATTERN SUPPORTS TEMPERATURES A LITTLE ABOVE NORMAL DURING THE PERIOD. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... MODERATE HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE TAF PERIOD. HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL CONTINUE CONTROL THE WEATHER. THE AIR MASS WILL REMAIN RELATIVELY DRY WITH LITTLE IN THE WAY OF CLOUDS. WINDS WILL BE SOUTHWEST TO WEST 5 TO 10 KNOTS WITH OCCASIONAL GUST UP TO 18 KTS THROUGH THE AFTERNOON. LIGHT AND VARIABLE WILL RETURN THIS EVENING AS AN INVERSION DEVELOPS. THE NAM AND RUC MODELS INDICATED INCREASING LOW LEVEL MOISTURE FOR THE POSSIBILITY OF FOG OR STRATUS DEVELOPMENT AT AGS AND OGB 08/09Z THROUGH 08/12Z. THE SREF MODEL KEPT CIG/VSBY RESTRICTIONS SOUTHEAST OF THE TAF SITES. GIVEN A DRY AIR MASS AND THE DEVELOPMENT OF A LOW LEVEL JET FOR BOUNDARY LAYER MIXING AS WELL AS VERY LOW CONFIDENCE...WILL NOT INCLUDE FOG OVERNIGHT. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED THURSDAY THROUGH SUNDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS POCATELLO ID
900 AM MDT WED MAY 7 2014 .UPDATE...PRECIPITATION CONTINUES THIS MORNING WITH SNOW LEVELS RIGHT AROUND 5000 FEET. ACCUMULATIONS THUS FAR HAVE BEEN NO MORE THAN A DUSTING BUT STILL EXPECTING SNOW LEVELS TO RISE THROUGH THE DAY TODAY TO AROUND 7000 FEET. NAM AND HRRR BOTH ARE CONTINUING TO SHOW FAVORED CONVECTION IN THE SOUTH AND EAST HIGHLANDS WITH ISOLATED THUNDERSTORMS POSSIBLE. DEPENDING ON THE AMOUNT OF CLEARING IN THE CENTRAL MOUNTAINS...CONVECTION IS POSSIBLE IN THOSE AREAS AS WELL. WINDS NEAR AMERICAN FALLS RESERVOIR ARE STILL NORTHEAST AND STRONG ENOUGH TO SUPPORT THE LAKE WIND ADVISORY THAT IS IN EFFECT. STILL LOOKS LIKE A WIND SHIFT WILL HAPPEN EARLY AFTERNOON IN THAT AREA SO EXPIRING THE LAKE WIND AROUND 2 PM STILL LOOKS GOOD. ALL GRIDS STILL LOOK ON TRACK SO DID NOT MAKE ANY CHANGES. EP && .PREV DISCUSSION... /ISSUED 310 AM MDT WED MAY 7 2014/ SHORT TERM...TODAY THROUGH FRIDAY NIGHT. THE CURRENT SATELLITE IMAGERY WAS SHOWING AN UPPER LOW ROTATING INTO SW UTAH WHILE ASSOCIATED MOISTURE AND SHOWERS LIFTED NORTH INTO SE IDAHO. MODELS SUGGEST THAT THE UPPER LOW WILL LIFT NNE TODAY THROUGH UTAH LEAVING SE IDAHO UNDER A MOIST-UNSTABLE AIRMASS. AN INVERTED SURFACE LOW EXTENDING FROM COLORADO NE INTO SE IDAHO WILL SUPPORT NORTH WINDS THROUGHOUT THE UPPER VALLEY TODAY WHILE WEST WINDS SPREAD EAST THROUGH THE ERN MAGIC VALLEY. TOUGH CALL TODAY ON HOW LONG AND/OR HOW STRONG THE NORTH WINDS WILL BE ACROSS THE AMERICAN FALLS RESERVOIR. NEARBY OBS ARE CURRENTLY SHOWING NE WINDS NEAR ADVISORY LEVELS...THUS WILL PUSH A LAKE WIND ADV OUT THE DOOR WITH THE MORNING PACKAGE. THE LOW PASSES EAST OVERNIGHT WITH DRIER CONDITIONS SPREADING INTO THE REGION FROM THE WEST. A NEGATIVELY TILTED PAC TROUGH SWINGS INTO THE NW STATES THURSDAY AFTERNOON...SPREADING EAST ACROSS SRN IDAHO THURSDAY NIGHT/FRIDAY MORNING WITH ANOTHER ROUND OF WIDESPREAD PRECIPITATION AND BREEZY/WINDY CONDITIONS ANTICIPATED FOR SE IDAHO. HUSTON LONG TERM...SATURDAY THROUGH TUESDAY. THE 7/00Z RUN OF THE GFS HAS INCREASED THE WAVE AMPLITUDE AND OVERALL MOVED CLOSER IN LINE TO THE ECMWF WHICH TAKES A LOW NEAR THE OREGON COAST SATURDAY MORNING AND MOVES IT OVER UTAH BY SUNDAY MORNING. KEEPING CHANCE POPS IN THE MOUNTAINS SATURDAY AND SATURDAY NIGHT APPEARS TO BE A GOOD MOVE AND MAY NEED TO BE INCREASED SOME MORE. THAT LEAVES A HIGH PRESSURE RIDGE DEVELOPING NEAR THE WEST COAST BY SUNDAY AND DECREASING SHOWERS IN SOUTHEAST IDAHO SUNDAY EVENING. THE LATEST ECMWF IS NOT WITHOUT CHANGES. THERE ARE TWO MINOR DISTURBANCE CROSSING NORTHERN IDAHO...ONE MONDAY AND ANOTHER TUESDAY THAT RESULT IN A FLATTER RIDGE AND TAKING A LITTLE EDGE OFF THE WARM UP FOR EARLY NEXT WEEK. RS AVIATION...FOR KBYI...KPIH AND KIDA MORE SCATTERED RAIN SHOWERS ARE IN ORDER BETWEEN 10Z AND 19Z TODAY AS THE CIRCULATION IN NORTHWEST UTAH MOVES EAST TO NORTHEAST. THE INSTABILITY IS NOT AS STRONG AS YESTERDAY BUT CANT RULE OUT AN ISOLATED THUNDERSTORM IN THE CARIBOU HIGHLANDS AND BEAR LAKE AREA THIS AFTERNOON. MVFR CEILINGS WITH THE SHOWERS A GOOD BET. HIGH PRESSURE MOVES IN TONIGHT AND THURSDAY PROVIDING A BREAK IN THE WEATHER UNTIL A COLD FRONT COMES THROUGH FRIDAY MORNING. RS && .PIH WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY UNTIL 2 PM MDT THIS AFTERNOON IDZ021. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1013 PM CDT THU MAY 8 2014 .DISCUSSION... 818 PM CDT FOR EVENING UPDATE... SHOWER/THUNDERSTORM COVERAGE AND INTENSITY PLAYING OUT AS EARLIER DISCUSSED...WITH CONVECTION GENERALLY STRUGGLING AS IT MOVES INTO NORTH CENTRAL IL. LOSS OF DIURNAL HEATING AND ASSOCIATED LOW-LEVEL INSTABILITY HAS DECREASED MARGINAL SEVERE THREAT...THOUGH WILL CONTINUE TO MONITOR CELLS MOVING OUT OF WEST-CENTRAL IL FOR ANY STRONGER CORES THAT MIGHT STILL BE ABLE TO PRODUCE SOME SMALL HAIL OR MARGINAL WIND GUSTS. OTHERWISE...AREA OF RAIN AND EMBEDDED THUNDER OVER EASTERN MISSOURI IS EXPECTED TO SHIFT NORTHEAST INTO OUR REGION AFTER MIDNIGHT IN ASSOCIATION WITH MID-LEVEL SHORT WAVE AND INCREASING MOISTURE TRANSPORT ON 40-50 KT 850 HPA JET. REGIONAL RADAR MOSAIC AND ORIENTATION OF MOIST PLUME OVERNIGHT SUGGESTS FOCUS WILL BE IN OUR CENTRAL/SOUTHEASTERN CWA...THOUGH LARGER SCALE HEIGHT FALLS AHEAD OF DEEP UPPER TROUGH LIFTING INTO THE UPPER MIDWEST AND APPROACH OF SURFACE COLD FRONT TOWARD MORNING SHOULD BOTH WORK TO INCREASE COVERAGE OF SHOWERS/THUNDERSTORMS OVER NORTHWESTERN CWA AS WELL PRE-DAWN FRIDAY MORNING. EXTENT OF CLOUDINESS AND MORNING PRECIP RAISES QUESTIONS ABOUT EXTENT OF THUNDERSTORM/SEVERE THREAT FRIDAY AFTERNOON...THOUGH FRONT SLOWS UP IN THE AFTERNOON ACROSS NORTHWEST IN/EAST CENTRAL IL AND INDICATES BEST CHANCES FOR PRECIP/THUNDER FRIDAY AFTERNOON MAINLY ACROSS ABOUT THE SOUTHEAST 1/3 OF THE FA. HAVE MADE SOME ADJUSTMENTS TO HOURLY POP/WX GRIDS TO PROVIDE A LITTLE MORE DETAIL IN TIMING AND PLACEMENT OF EXPECTED ROUNDS OF PRECIP THROUGH FRIDAY...WITH POPS LOWERED FROM THE WEST/NORTHWEST BEHIND THE FRONT ON FRIDAY AND GRADIENT FROM NO POPS NORTHWEST TO LIKELY POPS IN OUR SOUTHEAST TIGHTENED UP. HAVE ALSO FOCUSED MENTION OF LOCALLY HEAVY RAINFALL FOR LATE TONIGHT/EARLY FRIDAY MORNING OVER CENTRAL/SOUTHEAST COUNTIES AS INDICATED ABOVE. UPDATED GRIDS...ZFP/LFP ALL ALREADY AVAILABLE. RATZER //PREV DISCUSSION... 312 PM CDT MAIN CONCERN FOR THE AREA REMAINS THE CHANCES FOR THUNDERSTORMS. FOR THE REMAINDER OF THE AFTERNOON AND INTO EARLY THIS EVENING...CONDITIONS SHOULD REMAIN QUIET AS THE AREA REMAINS IN A CAPPED WARM SECTOR. THE WARM FRONT HAS PUSHED WELL NO THE NORTH WHILE A COLD FRONT IS WELL TO THE WEST...EXTENDING FROM DEEPENING LOW PRESSURE OVER WRN IA/ERN NE SOUTHWEST THROUGH CNTRL KS/WRN OK. AS LONG AS THE ENVIRONMENT OVER THE LOCAL AREA REMAINS CAPPED...THE CHANCES FOR ANY PCPN WILL BE LIMITED. CURRENTLY...THE PRIMARY THUNDERSTORM THREAT IS INVOF THE COLD FRONT/SFC LOW WHERE SPC HAS ISSUED THE FIRST WATCH OF THE DAY OVER WRN IA/NWRN MN. AS SFC TEMPERATURES RISE INTO THE UPPER 80S ANTICIPATE THAT THE CAP WILL ERODE WITH TIME THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. HOWEVER...SOME DRIER AIR IS MIXING DOWN TO THE SURFACE THIS AND SFC DEWPOINTS HAVE DROPPED INTO THE UPPER 50S...BUT EXPECT THAT DEWPOINTS WILL REBOUND BACK INTO THE 60S THIS EVENING. SFC BASED INSTABILITY WILL BE ON THE INCREASE WHILE THE SFC LOW TRACKS TO THE WRN GREAT LAKES OVERNIGHT TONIGHT AND THE COLD FRONT PUSHES INTO NWRN IL. STRONG WARM ADVECTION IN THE WARM SECTOR AND LOW LEVEL FORCING WITH THE COLD FRONT COMBINED WITH UPPER LEVEL FORCING AS THE REGION WILL BE UNDER THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAM...WILL PROVIDE THE FOCUS FOR THE DEVELOPMENT OF STRONG TO...POTENTIALLY...SEVERE THUNDERSTORMS ACROSS NRN IL THROUGH THE NIGHT. WHILE THERE MAY STILL BE A CHANCE FOR DISCRETE SUPERCELLS TO DEVELOP AHEAD OF THE COLD FRONT...THE MORE LIKELY CONVECTIVE MODE TONIGHT IS SHAPING UP TO BE MORE LINEAR...AS THE CONVECTIVE ACTIVITY TO THE WEST CONSOLIDATES INTO LINES. THUS...THE MORE LIKELY SEVERE THREAT SHOULD BE LARGE HAIL AND STRONG DAMAGING WINDS. HEAVY RAINFALL WILL ALSO BE A CONCERN WITH THE THUNDERSTORMS TONIGHT WITH PWATS FORECAST TO BE ARND 1.7 INCHES. HOWEVER...WITH THE FRONTAL SYSTEM STEADILY PROGRESSIVE TO THE EAST...DO NOT ANTICIPATE SIGNIFICANT ECHO TRAINING. SO...LOCALLY HEAVY RAINFALL MAY LEAD TO URBAN FLOODING CONCERNS...DO NOT ANTICIPATE A WIDESPREAD FLASH FLOOD THREAT. THE SHORT RANGE MODEL GUIDANCE IS RELATIVELY CONSISTENT ON THE STEADY PROGRESSION OF THE COLD FRONT...CLEARING THE ERN PORTIONS OF THE CWA BY EARLY TOMORROW AFTERNOON...THOUGH SOME LINGERING SHOWERS ARE POSSIBLE INTO THE LATE AFTERNOON HOURS...ESPECIALLY FOR THE NWRN INDIANA COUNTIES. FOLLOWING THE PASSAGE OF THE COLD FRONT...A PERIOD OF RELATIVE CALM IS EXPECTED FOR FRIDAY NIGHT AND SATURDAY AS WEAK HIGH PRESSURE SPREADS OVER THE MIDWEST. TEMPERATURES FOR FRIDAY AND SATURDAY SHOULD MODERATE INTO THE LOWER TO MIDDLE 70S. BRISK SWLY FLOW PERSISTING ON FRIDAY SHOULD ALLOW THE WARMER AIR TO PENETRATE ALL THE WAY TO THE LAKE FRONT...BUT FOR SATURDAY...A WEAK SFC PRESSURE GRADIENT AND RELATIVELY LIGHT WINDS SHOULD ALLOW FOR A LAKE BREEZE TO DEVELOP. WITH ANOTHER LOW DEVELOPING OVER THE CNTRL PLAINS AND HIGH PRESSURE OVER THE SERN CONUS...SFC WINDS SHOULD BE PREVAILING SLY TO SWLY...SO...THE LAKE BREEZE SHOULD ASSUME A NW-SE ORIENTATION AND LIKELY ONLY MOVE INLAND FROM CHICAGO NORTHWARD. WHILE MUCH OF THE CWA ENJOYS TEMPERATURES BACK IN THE MIDDLE 70S ON SATURDAY...THE LAKEFRONT LOCATIONS FROM CHICAGO TO WAUKEGAN SHOULD SEE HIGHS ONLY IN THE LOWER TO MIDDLE 60S. THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL COME BY SATURDAY EVENING AS THE AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS THROUGH THE UPPER MIDWEST AND DRAGGING ANOTHER COLD FRONT ACROSS THE AREA. THIS SYSTEM IS NOT LOOKING QUITE AS DYNAMIC AS THE SYSTEM EXPECTED THIS EVENING...SO...THE CHANCES FOR MORE SEVERE WEATHER ARE LOW. A SRN STREAM SYSTEM LIFTING OUT OF THE SRN ROCKIES BY SATURDAY NIGHT WILL DEVELOP A WAVE ON THE SRN END OF THE FRONT. THIS WAVE IS FORECAST TO RIPPLE ALONG THE BOUNDARY TO THE NORTHEAST...WHICH WILL HELP TO SLOW THE OVERALL PROGRESSION OF THE SYSTEM AND A STRUNG OUT FRONTAL SYSTEM IS EXPECTED TO EXTEND FROM THE RED RIVER VALLEY INTO THE WRN GREAT LAKES BY SUNDAY NIGHT. WITH THE FRONT NOT EXPECTED TO PUSH EAST OF THE AREA UNTIL TUESDAY MORNING...THERE WILL BE AN EXTENDED CHANCE FOR SHOWERS AND THUNDERSTORMS FROM LATE SATURDAY NIGHT THROUGH TUESDAY MORNING. FOR THE LONGER RANGE FORECAST PERIOD...FROM TUESDAY THROUGH THURSDAY...FOLLOWING THE PASSAGE OF THE COLD FRONT AND THE ASSOCIATED LOW...THERE WILL STILL BE LINGERING CHANCES FOR SHOWERS WITH A SERIES OF NRN STREAM SHORT WAVES DROPPING OUT OF CANADA RIGHT ON THE HEELS OF THE EXITING SYSTEM. WITH SOME UNCERTAINTY TO THE EXACT TIMING OF THIS SERIES OF SHORTWAVES...WILL CARRY AT LEAST CHANCE POPS THROUGH THE EXTENDED PERIOD. WITH THE TRAIN OF SHORTWAVES CARVING OUT A LONG WAVE TROUGH OVER THE GREAT LAKES AND MIDWEST...TEMPERATURES FOR TUESDAY THROUGH THURSDAY SHOULD BE BACK TO WELL BELOW NORMAL. HIGHS FOR TUESDAY THROUGH THURSDAY ARE EXPECTED TO BE IN THE LOWER TO MIDDLE 60S WITH EVEN SOME UPPER 50S POSSIBLE ALONG THE LAKEFRONT. OVERNIGHT LOWS THROUGH THE EXTENDED PERIOD SHOULD ONLY BE IN THE 40S. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * GUSTY SOUTHERLY WINDS THIS EVENING. * A PERIOD OR TWO OF SHRA/PSBL ISOLATED TSRA LATE THIS EVENING THROUGH EARLY FRIDAY MORNING...WITH A CHANCE FOR ADDITIONAL SHRA/TSRA THROUGH MID FRIDAY MORNING. * MVFR CEILINGS FRIDAY MORNING. RC //DISCUSSION...UPDATED 00Z... LOW PRESSURE IS CENTERED NEAR THE MN/IA BORDER EAST OF FSD EARLY THIS EVENING...WITH A COLD FRONT TRAILING TO ITS SOUTH. GUSTY SOUTH-SOUTHWEST WINDS CONTINUE AT ALL TAF SITES WHICH ARE ENTRENCHED IN THE WARM SECTOR OF THE STORM SYSTEM. AN UPPER DISTURBANCE IN ADVANCE OF THE SYSTEM IS RESULTING IN SCT TSRA FROM NORTHEAST MO TO NORTHWEST/NORTH CENTRAL IL...WITH TSRA AT LEAST IN THE VICINITY OF RFD FOR THE NEXT FEW HOURS. SCT SHRA/TSRA SHOULD GRADUALLY DEVELOP TOWARD THE EASTERN TERMINALS LATER THIS EVENING BUT BASED ON TRENDS HAVE PUSHED BACK TIMING A FEW HOURS. CLOSER APPROACH OF COLD FRONT OVERNIGHT INTO EARLY FRIDAY SHOULD RESULT IN ANOTHER ROUND OF SCT TO WIDESPREAD SHRA/TSRA. OVERALL DO NOT HAVE HIGH CONFIDENCE IN PREVAILING TSRA AT ANY TAF SITE SO HAVE BACKED OFF TO VICINITY MENTION BUT WILL AMEND AS NEEDED. THERE IS UNCERTAINTY WITH IMPACT OF OVERNIGHT CONVECTION ON INSTABILITY FRIDAY MORNING AND ALSO FOCUS SHOULD BE TRENDING MAINLY TO THE SOUTHEAST OF THE EASTERN TERMINALS. FEEL THAT CHANCES FOR ADDITIONAL THUNDER ARE LOW BUT NONZERO...AND HAVE COVERED POTENTIAL WITH A VCSH MENTION. OTHER CONCERN IS FOR A PERIOD OF MVFR CIGS FROM EARLY TO MID MORNING FRIDAY. SUSPECT THAT GUIDANCE INDICATING LOW MVFR AND EVEN IFR CIGS IS OVERDONE WITH LOW LEVEL MOISTURE SO HAVE MAINTAINED A HIGH END MVFR CIG WHICH SHOULD SCATTER BY LATE MORNING. AS FRONTAL TROUGH CROSSES THE TERMINALS...WINDS WILL VEER SOUTHWESTERLY AND THEN WESTERLY WITH INCREASED SPEEDS/GUSTS THAT WILL LIKELY QUICKLY DIMINISH WITH SUNSET FRIDAY EVENING AS WEAK HIGH PRESSURE SPREADS OVER THE AREA. RC //ORD AND MDW CONFIDENCE...UPDATED 03Z... * HIGH WITH WIND TRENDS. * MEDIUM-HIGH IN SHRA OVERNIGHT...MEDIUM CONFIDENCE IN TIMING...LOW IN VCTS/PREVAILING TSRA AT TERMINALS. * LOW IN ADDITIONAL TSRA THROUGH MID FRIDAY MORNING. * MEDIUM IN A PERIOD OF MVFR CIGS FRIDAY MORNING. RC //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... SATURDAY...DAYTIME VFR...LAKE BREEZE WIND SHIFT POSSIBLE. SHRA/TSRA POSSIBLE OVERNIGHT. SUNDAY...PERIODS OF SHRA/TSRA POSSIBLE. SOUTHERLY WINDS. MONDAY...PERIODS OF SHRA/TSRA POSSIBLE. SOUTH TO SOUTHWEST WINDS. TUESDAY AND WEDNESDAY...CHANCE SHRA. RC && .MARINE... 218 PM CDT A WARM FRONT DRAPED ACROSS THE NORTHERN PART OF THE LAKE LATE THIS AFTERNOON WILL SHIFT NORTH OF THE LAKE THIS EVENING...YIELDING SOUTHERLY WINDS ACROSS THE ENTIRE LAKE. GUSTS AROUND 25 KT...AT TIMES POSSIBLY REACHING 30 KT BRIEFLY...WILL CONTINUE ACROSS ILLINOIS AND INDIANA NEAR SHORE AREAS THROUGH TONIGHT AND INTO FRIDAY. STORMS LOOK LIKELY LATE TONIGHT INTO FRIDAY MORNING...A FEW OF WHICH COULD BE GUSTY. AS THE LOW PRESSURE DRIVING THE SOUTHERLY WINDS MOVES FROM IOWA THIS AFTERNOON THROUGH ONTARIO ON FRIDAY IT WILL STEER A COLD FRONT OVER LAKE MICHIGAN ON FRIDAY NIGHT. THIS FRONT WILL BE WEAKENING THOUGH AND ONLY BRIEFLY TURN THE WINDS WEST-SOUTHWEST BEFORE TURNING BACK SOUTHERLY THIS WEEKEND. THE NEXT AREA OF LOW PRESSURE WILL NEAR THE LAKE DURING LATE SUNDAY INTO MONDAY. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 PM FRIDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion National Weather Service Lincoln IL 840 PM CDT Thu May 8 2014 .DISCUSSION... ISSUED 835 PM CDT Thu May 8 2014 Convection continues to make slow progress over west central IL this evening, now advancing along and just east of I-55. Had a couple of reports of wind gusts of 50 to 60 mph with the storms late this afternoon but those were few and far between. With the loss of daytime heating, our instability parameters are not very impressive across central IL this evening with CAPE values over most of the area now down below 1000 j/kg. Short term models suggest as low level jet increases to our southwest later this evening, we should see more widespread rainfall across the forecast area during the early morning hours along with mild temperatures. Have already sent out an update to address the storms moving into west central IL earlier this evening, but will send out another update by 900 pm to address the current thinking on the timing of the rain into eastern IL later this evening. Smith && .AVIATION... ISSUED 605 PM CDT Thu May 8 2014 Band of showers and thunderstorms will affect our western TAF sites this evening with an overall increase in coverage later tonight across the east which will gradually bring cigs to MVFR category during the early morning hours. First band of rain will stay along and west of I55 early this evening with an increase in coverage to the east roughly after 03z. Once the MVFR ceilings set in aftr 05z in the west and 08z in the east, they are expected to hold over the area with rain and isold thunder into the morning hours of Friday. Next problem will be with the threat for redevelopment of showers and thunderstorms along a weakening cold front tomorrow afternoon and evening. For now will include a VCTS group for DEC and CMI and see how the overnight precip affects coverage of rain tomorrow afternoon. Surface winds will continue from a southerly direction at 12 to 17 kts tonight with an occasional gust up to 25 kts at times this evening. Winds will veer more into a southwest to west direction at 12 to 17 kts on Friday with gusts around 25 kts, especially in the afternoon. Smith && .PREV DISCUSSION... ISSUED 258 PM CDT Thu May 8 2014 Temperatures warming nicely across the forecast area today, with gusty south-southwest winds and mainly some high clouds. Mostly in the mid 80s, although some 90 degree temperatures reported at Champaign and Rantoul at 2 pm. Convection developing as expected west of the Mississippi River, with one cluster over Minnesota/Iowa along the warm front, and the second developing over western Missouri just ahead of the cold front. Both fronts are tied into a surface low over northeast Nebraska. Initial forecast concerns are with thunderstorm trends through Friday including severe threat, followed by timing of showers/storms for much of the first half of next week. SHORT TERM...Tonight through Friday Night: Latest mesoscale analysis showing CAPE`s of 1000-1500 J/kg over the forecast area, with the cap eroding along the Mississippi River. Latest HRRR has the storms reaching the Illinois River valley by around 6 pm and I-57 toward 9-10 pm. Areas west of I-55 most likely to see any severe weather as the instability will be decreasing by the time the storms make it further east. Hail/wind remains the primary concern with the storms. Secondary line of showers/storms immediately ahead of the front will begin to move in after midnight, but think the severe threat will be be over by that point. Extent of overnight convection will dictate where the severe threat is for Friday. Areas south of I-70 would be most likely as the front comes in and with outflows from the earlier convection around, but additional instability would likely have to come during the afternoon in between periods of storms. Will mention categorical PoP`s over 80% across the southeast third of the forecast area through the day, with not the rain not fully moving out of the southeast CWA until closer to midnight. Further west, will largely go dry west of I-55 during the afternoon. LONG TERM...Saturday through Thursday: Short period of dry weather on tap for Saturday as a narrow ridge axis slides by, but next wave will be approaching from the Plains. Have added some slight chance PoP`s in the afternoon west of I-55, but main period of convection will develop Saturday night. Will introduce likely PoP`s late Saturday night across about the northwest 2/3 of the forecast area, lingering into Sunday across the north as remnants of an MCS move across the area. The forecast from Sunday night into Monday night is more of a challenge. The GFS is much faster than the ECMWF or Canadian models by surging a cold front through the area Monday night, while the latter models are close to 24 hours slower. This slower solution would keep a good part of Sunday night and Monday dry. This appears to be tied into phasing of the long wave trough across the Rockies Sunday night, with the GFS featuring a more progressive wave and the ECMWF cutting off a low over the northern Dakotas for a time early next week. Am trending the blended model grids on the slower side, but have not completely eliminated any PoP`s Monday/Tuesday. Deep upper trough over the central U.S. to provide a period of cooler weather for the middle of the week. Will see highs only in the 60s much of the Tuesday-Thursday period. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
709 PM CDT THU MAY 8 2014 .MESOSCALE DISCUSSION...549 PM CDT ISOLATED-SCATTERED THUNDERSTORMS DEVELOPING OVER WESTERN IL LATE THIS AFTERNOON EXPECTED TO CONTINUE TO SPREAD INTO NORTH CENTRAL IL EARLY THIS EVENING. THESE CELLS APPEAR TO BE FOCUSED IN A REGION OF WEAK LOW-LEVEL MOIST CONVERGENCE ALONG LEADING EDGE OF SLIGHTLY HIGHER (LOW 60S) SFC DEW POINT TEMPS...AND IN RESPONSE TO 45-50 KT MID-LEVEL SPEED MAX ASSOCIATED WITH A MINOR-AMPLITUDE SHORT WAVE LIFTING ACROSS MO-EASTERN IA. RAP/SPC MESOANALYSIS INDICATES 1000-1500 J/KG MLCAPE AND 30-40 KT OF EFFECTIVE/6 KM BULK SHEAR SUFFICIENT FOR ORGANIZED UPDRAFTS. A FEW CELLS HAVE BRIEFLY DEVELOPED STRONG CORES ALOFT...PARTICULARLY THE STORM CURRENTLY NORTH OF GALESBURG WHICH EARLIER HAD 50 DBZ REFLECTIVITY AROUND 30 KFT...BUT RELATIVELY WARM PROFILE SUGGESTS LARGE HAIL NOT A BIG THREAT GIVEN THE LACK OF STRONG STEEP MID-LEVEL LAPSE RATES. FARTHER EAST INTO OUR CWA...AND EAST OF MOISTURE DISCONTINUITY...SFC DEW POINT TEMPS FALL OFF INTO THE MID-UPPER 50S. WHILE STORMS WILL LIKELY CONTINUE TO DEVELOP NORTHEAST IN ASSOCIATION WITH APPROACHING SHORT WAVE...THIS SUGGESTS THAT CONVECTION MAY STRUGGLE TO MAINTAIN INTENSITY SEEN OVER WESTERN IL THIS AFTERNOON. LOW-LEVEL LAPSE RATES ARE RATHER STEEP ACROSS OUR CWA (WITH DCAPE 1000+ J/KG PER RAP/SPC ANALYSIS) IN SLIGHTLY DRIER WELL-MIXED BOUNDARY LAYER...THOUGH LOW LEVEL LAPSE RATES SHOULD TEND TO DECREASE DIURNALLY AS WE APPROACH/PASS SUNSET. THEREFORE...IT APPEARS THAT A RATHER MARGINAL SEVERE THREAT EXISTS MAINLY FOR THE FAR WESTERN CWA COUNTIES (AND PERHAPS MAINLY WESTERN PARTS OF OGLE/LEE COUNTIES) INTO EARLY EVENING MAINLY FOR DAMAGING WIND GUSTS/MARGINAL HAIL IF ANY STRONGER STORMS DEVELOP THAT FAR EAST. OTHERWISE...ADDITIONAL SHOWERS AND THUNDERSTORMS EXPECTED LATER TONIGHT AS UPPER TROUGH SLOWLY APPROACHES FROM THE WEST...AND MOIST AXIS SHIFTS EAST AHEAD OF COLD FRONT TO OUR WEST. THREAT FROM THESE STORMS APPEARS TO BE MAINLY LOCALLY HEAVY RAINFALL WITH 1.5"+ PRECIPITABLE MOISTURE AXIS DEVELOPS EAST AND 40-50 KT SOUTHWESTERLY LOW LEVEL JET INCREASES MOISTURE TRANSPORT INTO THE REGION. RATZER && .DISCUSSION... 312 PM CDT MAIN CONCERN FOR THE AREA REMAINS THE CHANCES FOR THUNDERSTORMS. FOR THE REMAINDER OF THE AFTERNOON AND INTO EARLY THIS EVENING...CONDITIONS SHOULD REMAIN QUIET AS THE AREA REMAINS IN A CAPPED WARM SECTOR. THE WARM FRONT HAS PUSHED WELL NO THE NORTH WHILE A COLD FRONT IS WELL TO THE WEST...EXTENDING FROM DEEPENING LOW PRESSURE OVER WRN IA/ERN NE SOUTHWEST THROUGH CNTRL KS/WRN OK. AS LONG AS THE ENVIRONMENT OVER THE LOCAL AREA REMAINS CAPPED...THE CHANCES FOR ANY PCPN WILL BE LIMITED. CURRENTLY...THE PRIMARY THUNDERSTORM THREAT IS INVOF THE COLD FRONT/SFC LOW WHERE SPC HAS ISSUED THE FIRST WATCH OF THE DAY OVER WRN IA/NWRN MN. AS SFC TEMPERATURES RISE INTO THE UPPER 80S ANTICIPATE THAT THE CAP WILL ERODE WITH TIME THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. HOWEVER...SOME DRIER AIR IS MIXING DOWN TO THE SURFACE THIS AND SFC DEWPOINTS HAVE DROPPED INTO THE UPPER 50S...BUT EXPECT THAT DEWPOINTS WILL REBOUND BACK INTO THE 60S THIS EVENING. SFC BASED INSTABILITY WILL BE ON THE INCREASE WHILE THE SFC LOW TRACKS TO THE WRN GREAT LAKES OVERNIGHT TONIGHT AND THE COLD FRONT PUSHES INTO NWRN IL. STRONG WARM ADVECTION IN THE WARM SECTOR AND LOW LEVEL FORCING WITH THE COLD FRONT COMBINED WITH UPPER LEVEL FORCING AS THE REGION WILL BE UNDER THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAM...WILL PROVIDE THE FOCUS FOR THE DEVELOPMENT OF STRONG TO...POTENTIALLY...SEVERE THUNDERSTORMS ACROSS NRN IL THROUGH THE NIGHT. WHILE THERE MAY STILL BE A CHANCE FOR DISCRETE SUPERCELLS TO DEVELOP AHEAD OF THE COLD FRONT...THE MORE LIKELY CONVECTIVE MODE TONIGHT IS SHAPING UP TO BE MORE LINEAR...AS THE CONVECTIVE ACTIVITY TO THE WEST CONSOLIDATES INTO LINES. THUS...THE MORE LIKELY SEVERE THREAT SHOULD BE LARGE HAIL AND STRONG DAMAGING WINDS. HEAVY RAINFALL WILL ALSO BE A CONCERN WITH THE THUNDERSTORMS TONIGHT WITH PWATS FORECAST TO BE ARND 1.7 INCHES. HOWEVER...WITH THE FRONTAL SYSTEM STEADILY PROGRESSIVE TO THE EAST...DO NOT ANTICIPATE SIGNIFICANT ECHO TRAINING. SO...LOCALLY HEAVY RAINFALL MAY LEAD TO URBAN FLOODING CONCERNS...DO NOT ANTICIPATE A WIDESPREAD FLASH FLOOD THREAT. THE SHORT RANGE MODEL GUIDANCE IS RELATIVELY CONSISTENT ON THE STEADY PROGRESSION OF THE COLD FRONT...CLEARING THE ERN PORTIONS OF THE CWA BY EARLY TOMORROW AFTERNOON...THOUGH SOME LINGERING SHOWERS ARE POSSIBLE INTO THE LATE AFTERNOON HOURS...ESPECIALLY FOR THE NWRN INDIANA COUNTIES. FOLLOWING THE PASSAGE OF THE COLD FRONT...A PERIOD OF RELATIVE CALM IS EXPECTED FOR FRIDAY NIGHT AND SATURDAY AS WEAK HIGH PRESSURE SPREADS OVER THE MIDWEST. TEMPERATURES FOR FRIDAY AND SATURDAY SHOULD MODERATE INTO THE LOWER TO MIDDLE 70S. BRISK SWLY FLOW PERSISTING ON FRIDAY SHOULD ALLOW THE WARMER AIR TO PENETRATE ALL THE WAY TO THE LAKE FRONT...BUT FOR SATURDAY...A WEAK SFC PRESSURE GRADIENT AND RELATIVELY LIGHT WINDS SHOULD ALLOW FOR A LAKE BREEZE TO DEVELOP. WITH ANOTHER LOW DEVELOPING OVER THE CNTRL PLAINS AND HIGH PRESSURE OVER THE SERN CONUS...SFC WINDS SHOULD BE PREVAILING SLY TO SWLY...SO...THE LAKE BREEZE SHOULD ASSUME A NW-SE ORIENTATION AND LIKELY ONLY MOVE INLAND FROM CHICAGO NORTHWARD. WHILE MUCH OF THE CWA ENJOYS TEMPERATURES BACK IN THE MIDDLE 70S ON SATURDAY...THE LAKEFRONT LOCATIONS FROM CHICAGO TO WAUKEGAN SHOULD SEE HIGHS ONLY IN THE LOWER TO MIDDLE 60S. THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL COME BY SATURDAY EVENING AS THE AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS THROUGH THE UPPER MIDWEST AND DRAGGING ANOTHER COLD FRONT ACROSS THE AREA. THIS SYSTEM IS NOT LOOKING QUITE AS DYNAMIC AS THE SYSTEM EXPECTED THIS EVENING...SO...THE CHANCES FOR MORE SEVERE WEATHER ARE LOW. A SRN STREAM SYSTEM LIFTING OUT OF THE SRN ROCKIES BY SATURDAY NIGHT WILL DEVELOP A WAVE ON THE SRN END OF THE FRONT. THIS WAVE IS FORECAST TO RIPPLE ALONG THE BOUNDARY TO THE NORTHEAST...WHICH WILL HELP TO SLOW THE OVERALL PROGRESSION OF THE SYSTEM AND A STRUNG OUT FRONTAL SYSTEM IS EXPECTED TO EXTEND FROM THE RED RIVER VALLEY INTO THE WRN GREAT LAKES BY SUNDAY NIGHT. WITH THE FRONT NOT EXPECTED TO PUSH EAST OF THE AREA UNTIL TUESDAY MORNING...THERE WILL BE AN EXTENDED CHANCE FOR SHOWERS AND THUNDERSTORMS FROM LATE SATURDAY NIGHT THROUGH TUESDAY MORNING. FOR THE LONGER RANGE FORECAST PERIOD...FROM TUESDAY THROUGH THURSDAY...FOLLOWING THE PASSAGE OF THE COLD FRONT AND THE ASSOCIATED LOW...THERE WILL STILL BE LINGERING CHANCES FOR SHOWERS WITH A SERIES OF NRN STREAM SHORT WAVES DROPPING OUT OF CANADA RIGHT ON THE HEELS OF THE EXITING SYSTEM. WITH SOME UNCERTAINTY TO THE EXACT TIMING OF THIS SERIES OF SHORTWAVES...WILL CARRY AT LEAST CHANCE POPS THROUGH THE EXTENDED PERIOD. WITH THE TRAIN OF SHORTWAVES CARVING OUT A LONG WAVE TROUGH OVER THE GREAT LAKES AND MIDWEST...TEMPERATURES FOR TUESDAY THROUGH THURSDAY SHOULD BE BACK TO WELL BELOW NORMAL. HIGHS FOR TUESDAY THROUGH THURSDAY ARE EXPECTED TO BE IN THE LOWER TO MIDDLE 60S WITH EVEN SOME UPPER 50S POSSIBLE ALONG THE LAKEFRONT. OVERNIGHT LOWS THROUGH THE EXTENDED PERIOD SHOULD ONLY BE IN THE 40S. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * GUSTY SOUTHERLY WINDS THIS EVENING. * A PERIOD OR TWO OF SHRA/SCT TSRA LATE THIS EVENING THROUGH EARLY FRIDAY MORNING...WITH A CHANCE FOR ADDITIONAL SHRA/TSRA THROUGH MID FRIDAY MORNING. * MVFR CEILINGS FRIDAY MORNING. RC //DISCUSSION...UPDATED 00Z... LOW PRESSURE IS CENTERED NEAR THE MN/IA BORDER EAST OF FSD EARLY THIS EVENING...WITH A COLD FRONT TRAILING TO ITS SOUTH. GUSTY SOUTH-SOUTHWEST WINDS CONTINUE AT ALL TAF SITES WHICH ARE ENTRENCHED IN THE WARM SECTOR OF THE STORM SYSTEM. AN UPPER DISTURBANCE IN ADVANCE OF THE SYSTEM IS RESULTING IN SCT TSRA FROM NORTHEAST MO TO NORTHWEST/NORTH CENTRAL IL...WITH TSRA AT LEAST IN THE VICINITY OF RFD FOR THE NEXT FEW HOURS. SCT SHRA/TSRA SHOULD GRADUALLY DEVELOP TOWARD THE EASTERN TERMINALS LATER THIS EVENING BUT BASED ON TRENDS HAVE PUSHED BACK TIMING A FEW HOURS. CLOSER APPROACH OF COLD FRONT OVERNIGHT INTO EARLY FRIDAY SHOULD RESULT IN ANOTHER ROUND OF SCT TO WIDESPREAD SHRA/TSRA. OVERALL DO NOT HAVE HIGH CONFIDENCE IN PREVAILING TSRA AT ANY TAF SITE SO HAVE BACKED OFF TO VICINITY MENTION BUT WILL AMEND AS NEEDED. THERE IS UNCERTAINTY WITH IMPACT OF OVERNIGHT CONVECTION ON INSTABILITY FRIDAY MORNING AND ALSO FOCUS SHOULD BE TRENDING MAINLY TO THE SOUTHEAST OF THE EASTERN TERMINALS. FEEL THAT CHANCES FOR ADDITIONAL THUNDER ARE LOW BUT NONZERO...AND HAVE COVERED POTENTIAL WITH A VCSH MENTION. OTHER CONCERN IS FOR A PERIOD OF MVFR CIGS FROM EARLY TO MID MORNING FRIDAY. SUSPECT THAT GUIDANCE INDICATING LOW MVFR AND EVEN IFR CIGS IS OVERDONE WITH LOW LEVEL MOISTURE SO HAVE MAINTAINED A HIGH END MVFR CIG WHICH SHOULD SCATTER BY LATE MORNING. AS FRONTAL TROUGH CROSSES THE TERMINALS...WINDS WILL VEER SOUTHWESTERLY AND THEN WESTERLY WITH INCREASED SPEEDS/GUSTS THAT WILL LIKELY QUICKLY DIMINISH WITH SUNSET FRIDAY EVENING AS WEAK HIGH PRESSURE SPREADS OVER THE AREA. RC //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH WITH WIND TRENDS. * MEDIUM-HIGH IN SHRA/VCTS OVERNIGHT...MEDIUM CONFIDENCE IN TIMING...LOW IN PREVAILING TSRA AT TERMINALS. * LOW IN ADDITIONAL TSRA THROUGH MID FRIDAY MORNING. * MEDIUM-HIGH IN A PERIOD OF MVFR CIGS FRIDAY MORNING. RC //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... SATURDAY...DAYTIME VFR...LAKE BREEZE WIND SHIFT POSSIBLE. SHRA/TSRA POSSIBLE OVERNIGHT. SUNDAY...PERIODS OF SHRA/TSRA POSSIBLE. SOUTHERLY WINDS. MONDAY...PERIODS OF SHRA/TSRA POSSIBLE. SOUTH TO SOUTHWEST WINDS. TUESDAY AND WEDNESDAY...CHANCE SHRA. RC && .MARINE... 218 PM CDT A WARM FRONT DRAPED ACROSS THE NORTHERN PART OF THE LAKE LATE THIS AFTERNOON WILL SHIFT NORTH OF THE LAKE THIS EVENING...YIELDING SOUTHERLY WINDS ACROSS THE ENTIRE LAKE. GUSTS AROUND 25 KT...AT TIMES POSSIBLY REACHING 30 KT BRIEFLY...WILL CONTINUE ACROSS ILLINOIS AND INDIANA NEAR SHORE AREAS THROUGH TONIGHT AND INTO FRIDAY. STORMS LOOK LIKELY LATE TONIGHT INTO FRIDAY MORNING...A FEW OF WHICH COULD BE GUSTY. AS THE LOW PRESSURE DRIVING THE SOUTHERLY WINDS MOVES FROM IOWA THIS AFTERNOON THROUGH ONTARIO ON FRIDAY IT WILL STEER A COLD FRONT OVER LAKE MICHIGAN ON FRIDAY NIGHT. THIS FRONT WILL BE WEAKENING THOUGH AND ONLY BRIEFLY TURN THE WINDS WEST-SOUTHWEST BEFORE TURNING BACK SOUTHERLY THIS WEEKEND. THE NEXT AREA OF LOW PRESSURE WILL NEAR THE LAKE DURING LATE SUNDAY INTO MONDAY. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 PM FRIDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 611 PM CDT Thu May 8 2014 .DISCUSSION... ISSUED 258 PM CDT Thu May 8 2014 Temperatures warming nicely across the forecast area today, with gusty south-southwest winds and mainly some high clouds. Mostly in the mid 80s, although some 90 degree temperatures reported at Champaign and Rantoul at 2 pm. Convection developing as expected west of the Mississippi River, with one cluster over Minnesota/Iowa along the warm front, and the second developing over western Missouri just ahead of the cold front. Both fronts are tied into a surface low over northeast Nebraska. Initial forecast concerns are with thunderstorm trends through Friday including severe threat, followed by timing of showers/storms for much of the first half of next week. SHORT TERM...Tonight through Friday Night: Latest mesoscale analysis showing CAPE`s of 1000-1500 J/kg over the forecast area, with the cap eroding along the Mississippi River. Latest HRRR has the storms reaching the Illinois River valley by around 6 pm and I-57 toward 9-10 pm. Areas west of I-55 most likely to see any severe weather as the instability will be decreasing by the time the storms make it further east. Hail/wind remains the primary concern with the storms. Secondary line of showers/storms immediately ahead of the front will begin to move in after midnight, but think the severe threat will be be over by that point. Extent of overnight convection will dictate where the severe threat is for Friday. Areas south of I-70 would be most likely as the front comes in and with outflows from the earlier convection around, but additional instability would likely have to come during the afternoon in between periods of storms. Will mention categorical PoP`s over 80% across the southeast third of the forecast area through the day, with not the rain not fully moving out of the southeast CWA until closer to midnight. Further west, will largely go dry west of I-55 during the afternoon. LONG TERM...Saturday through Thursday: Short period of dry weather on tap for Saturday as a narrow ridge axis slides by, but next wave will be approaching from the Plains. Have added some slight chance PoP`s in the afternoon west of I-55, but main period of convection will develop Saturday night. Will introduce likely PoP`s late Saturday night across about the northwest 2/3 of the forecast area, lingering into Sunday across the north as remnants of an MCS move across the area. The forecast from Sunday night into Monday night is more of a challenge. The GFS is much faster than the ECMWF or Canadian models by surging a cold front through the area Monday night, while the latter models are close to 24 hours slower. This slower solution would keep a good part of Sunday night and Monday dry. This appears to be tied into phasing of the long wave trough across the Rockies Sunday night, with the GFS featuring a more progressive wave and the ECMWF cutting off a low over the northern Dakotas for a time early next week. Am trending the blended model grids on the slower side, but have not completely eliminated any PoP`s Monday/Tuesday. Deep upper trough over the central U.S. to provide a period of cooler weather for the middle of the week. Will see highs only in the 60s much of the Tuesday-Thursday period. Geelhart && .AVIATION... ISSUED 605 PM CDT Thu May 8 2014 Band of showers and thunderstorms will affect our western TAF sites this evening with an overall increase in coverage later tonight across the east which will gradually bring cigs to MVFR category during the early morning hours. First band of rain will stay along and west of I55 early this evening with an increase in coverage to the east roughly after 03z. Once the MVFR ceilings set in aftr 05z in the west and 08z in the east, they are expected to hold over the area with rain and isold thunder into the morning hours of Friday. Next problem will be with the threat for redevelopment of showers and thunderstorms along a weakening cold front tomorrow afternoon and evening. For now will include a VCTS group for DEC and CMI and see how the overnight precip affects coverage of rain tomorrow afternoon. Surface winds will continue from a southerly direction at 12 to 17 kts tonight with an occasional gust up to 25 kts at times this evening. Winds will veer more into a southwest to west direction at 12 to 17 kts on Friday with gusts around 25 kts, especially in the afternoon. Smith && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1246 AM CDT WED MAY 7 2014 .DISCUSSION... 909 PM CDT CONVECTION DEVELOPING ACROSS THE FAR NORTH METRO PROMPTED A SPECIAL WEATHER STATEMENT ISSUANCE. THE FORECAST WAS UPDATED TO REFLECT SLIGHTLY HIGHER CHANCES OF THUNDER NORTH OF INTERSTATE 80 THE REST OF TONIGHT...AS WELL AS TO MAKE SOME HOURLY FORECAST TEMPERATURE ADJUSTMENTS. THE SURFACE STATIONARY FRONT REMAINS DRAPED WELL TO OUR SOUTH THIS EVE WITH 00Z RAOBS AND CURRENT PROFILER ANALYSIS INDICATING A 40-45 KT SRLY LOW-LEVEL JET HAVING DEVELOPED NORTH OF THIS INTO IA AND ACROSS NORTHERN IL. THIN ARCS OF TCU WERE NOTED ON LATE DAY VISIBLE SATELLITE AND OBSERVATIONS HAVE INDICATED AN INCREASING LAYER OF 8K-10K FT CIGS. THE 00Z DVN RAOB AND AREA AMDAR SOUNDINGS WERE INDICATING A MOISTENING AROUND THAT 800-750MB LAYER...WHICH WHEN LIFTED FROM THAT LAYER ON THE DVN SOUNDING WOULD PROVIDE OVER 1500 J/KG OF MUCAPE...THOUGH WITH STILL A MINOR CAP. AS A SUBTLE SHORT WAVE NEAR KANSAS CITY PROGRESSES NORTHEAST AND OVERALL MOISTURE TRANSPORT STRENGTHENS...WOULD EXPECT TO SEE THAT SLIGHT CAPPING OVERCOME WITH ISOLATED TO SCATTERED CONVECTION DEVELOPING ACROSS THE EASTERN IA/SOUTHERN WI REGION...AND POSSIBLY NORTHERN IL...ESPECIALLY GIVEN CURRENT STORM WAS ALREADY ABLE TO DEVELOP. IN ADDITION...THE TREND WITH THE HOURLY-RAN HRRR HAS BEEN TO INCREASE COVERAGE OF SHOWERS/STORMS EARLY OVERNIGHT...WHICH GIVEN CURRENT OBSERVATIONAL ANALYSIS MAKES SENSE. HAVE BOOSTED POPS SOME OVER THE NORTHERN TWO TIERS OF COUNTIES BUT REMAIN IN THE CHANCE CATEGORY. GIVEN THE RADAR TRENDS WITH THE MCHENRY/LAKE COUNTY STORM...HAVING SPRUNG TO 40 DBZ OVER 35K FT WITHIN THREE SCANS OF DEVELOPING...COULD STILL SEE AN ELEVATED HAILER OR TWO ACROSS FAR NORTHERN ILLINOIS. THE ENVIRONMENT FOR THESE REMAINS MORE SUPPORTIVE TO THE WEST AND NORTHWEST OF THE LOCAL AREA. THE MARINE LAYER CONTINUED TO RE-INFORCE ITSELF EARLY THIS EVE ACROSS THE NORTH AND CENTRAL PARTS OF THE CHICAGO METRO...WITH SOME MID 40S ALONG THE LAKE SHORE AND LOWER 50S STARTING TO REACH SOME OUTLYING AREAS. DID ADJUST MINS DOWN BUT INDICATED SORT OF A LEVELING OFF TREND TO THIS TEMPERATURE FALL...WITH EVEN POTENTIAL RISING LATE GIVEN INCREASING SURFACE DEW POINTS. LOOKING AHEAD TO WEDNESDAY...STILL SOME POSSIBILITY TO SEE ISOLATED CONVECTION IN THE MORNING AS A WEAK SHORT WAVE PASSES...AND THE 00Z NAM CONTINUES TO SHOW THIS SUBTLE FEATURE. COULD ALSO BE SOME FOG DEVELOPING ACROSS FAR SOUTHERN LAKE MICHIGAN DURING THE MORNING AS THE WARM FRONT AND HIGH DEW POINTS BUTT UP AGAINST THE COOL LAKE. WITH THE WARM FRONT LIKELY TO PROGRESS SLOWER OVER THE MARINE LAYER...IT COULD INDUCE THE FOG. HAVE NOT ADDED INTO THE FORECAST AT THIS TIME BUT SOMETHING WE WILL WATCH AS THAT WOULD POSSIBLY MOVE INTO LAKE ADJACENT AREAS OF THE CHICAGO METRO. MTF //PREV DISCUSSION... 329 PM CDT SHORT TERM...TONIGHT THROUGH FRIDAY... PRIMARY FORECAST CONCERNS ARE WITH HOW WARM TEMPERATURES GET TOMORROW AND THURSDAY AND ON THUNDERSTORM POTENTIAL. W/V IMAGERY SHOWS THE ONGOING AMPLIFICATION OF UPPER RIDGING OVER THE MIDWEST INDUCED BY A DEEP TROUGH/CLOSED LOW OVER THE SOUTHWEST US. AT THE SURFACE...LOW PRESSURE IS DEVELOPING OVER THE SOUTHERN HIGH PLAINS WITH THE VERY STRONG WARM FRONT THAT HAS BEEN IN PLACE OVER THE REGION THE PAST FEW DAYS STRETCHING ACROSS DOWNSTATE IL AND IN. STRONG WAA ALOFT NORTH OF THE BOUNDARY HAS ALLOWED FOR TEMPERATURES TO WARM ABOVE 70 SOUTH OF I-80...WHILE ONSHORE FLOW HAS RESULTED IN ANOTHER COOL DAY FOR LAKESHORE AREAS. TONIGHT... AS THE SFC WARM FRONT INCHES NORTH...A STRONG LOW LEVEL JET WILL DEVELOP WITH GOOD MOISTURE TRANSPORT AND CONVERGENCE FOCUSED ON THE NOSE OF THE LLJ INTO NORTHEAST IA AND FAR SOUTHERN WI. GUIDANCE ALSO HINTS AT A MIDLEVEL SHORTWAVE RIDING IN ON SOUTHWEST FLOW. DESPITE SOME MODELS SUGGESTING CONTRARY...CONTINUE TO THINK THAT FOCUS FOR CONVECTION TONIGHT WILL REMAIN MAINLY NORTH OF THE CWA...THOUGH COULD CLIP THE FAR NORTH...WHERE GENERALLY SLIGHT POPS WERE MAINTAINED LATE EVE THROUGH OVERNIGHT. GIVEN PRESENCE OF MODERATE MUCAPE AND STRONG EFFECTIVE DEEP LAYER SHEAR...IF ANY STORMS DO OCCUR OVER THE FAR NORTH...STRONGER STORMS COULD YIELD ISOLATED SEVERE HAIL. LOW TEMPS WILL RANGE FROM MID 40S IN FAR NORTHEAST NEAR THE LAKE TO AROUND 60 IN THE SOUTHWEST CWA. WEDNESDAY AND WEDNESDAY NIGHT... MAIN UNCERTAINTY IS WITH TIMING OF SFC WARM FRONT LIFTING NORTH THROUGH CWA...THOUGH HAVE SOME CONCERN FOR ELEVATED HIGH-BASED CONVECTION NORTH OF THE WARM FRONT DURING THE MORNING MAINLY NORTH OF I-88. PRIMARY FOCUS SHOULD STILL BE NORTH OF THE CWA...BUT DID ADD A SLIGHT POP FOR AREA MENTIONED ABOVE. BIG STORY TOMORROW IS THE RAPID FLIP TO SUMMER WARMTH AS THE WARM FRONT LIFTS NORTH AS 850/925 MB TEMPS RISE TO LEVELS SUPPORTING AT LEAST LOW-MID 80S IN THE WARM SECTOR. SOME HIGH RES GUIDANCE REALLY SLOWS THE NWD PROGRESS OF THE FRONT TOMORROW...BUT THESE MODELS SUCH AS THE NAM ARE LIKELY AFFECTED BY OUTFLOW FROM OVERNIGHT CONVECTION. THE IL NORTH SHORE WILL LIKELY REMAIN QUITE COOL INTO THE AFTERNOON BUT THEN THE WARM AIR SOUTH OF THE BOUNDARY WILL RUSH IN BY THE LATE AFTERNOON OR EARLY EVENING...WITH TEMPS JUMPING SEVERAL DEGREES. DEWPOINTS WILL ALSO RISE TO CLOSE TO OR AROUND 60 AS THE FRONT LIFTS NORTH...ADDING A BIT OF A MUGGY FEEL TO THE AIRMASS. THE AREA SHOULD BE CAPPED TO CONVECTION ON WEDNESDAY NIGHT WITH NO REAL FOCUS TO BREACH THE CAP SO HAVE MAINTAINED A DRY FCST. OVERNIGHT TEMPS WILL BE NORMAL FOR MID SUMMER IN THE MID AND UPPER 60S. THIS WILL PROVIDE A WARM STARTING POINT FOR THURSDAY. THURSDAY AND THURSDAY NIGHT... CONTINUE TO SUSPECT AFTER EXAMINING FORECAST SOUNDINGS THAT MUCH IF NOT ALL OF THE AREA COULD SEE A MAINLY DRY DAYTIME WITH THE WARM SECTOR FIRMLY IN PLACE AND A STRONG CAP INDICATED. MOST OF THE MIDLEVEL SHORTWAVE FORCING DURING DAY SHOULD AT MOST SKIRTH THE FAR NORTHWEST CWA AND SFC COLD FRONT WILL BE WELL BACK TO THE WEST UNTIL THE NIGHTTIME. HAVE MAINTAINED GENERAL IDEA OF GRADUALLY SPREADING IN CHANCE POPS BUT BASED ON TRENDS TODAY...COULD FORSEE NEEDING TO LOWER THESE. THIS IS DESPITE HIGHS AGAIN IN THE MID 80S AND DEWPOINTS AROUND 60 SUPPORTING MODERATE MLCAPE VALUES. MORE FAVORABLE FORCING WILL ARRIVE DURING THE EVENING AND THEN MOISTURE CONVERGENCE ASSOCIATED WITH THE APPROACHING COLD FRONT WILL SUPPORT HIGHER SHOWER/TSTM COVERAGE OVERNIGHT. ARGUING AGAINST WIDESPREAD SEVERE STORMS WILL BE DIURNALLY UNFAVORABLE TIMING...BUT ESPECIALLY WESTERN CWA COULD HAVE ENOUGH INSTABILITY STILL IN PLACE ALONG WITH STRONG DEEP LAYER SHEAR TO SUPPORT A WIND/HAIL THREAT. WITH FRONT REMAINING TO THE WEST THROUGH THE NIGHT...OVERNIGHT TEMPS WILL AGAIN BE QUITE MILD IN THE MID 60S. FRIDAY... REMAINS OF OVERNIGHT CONVECTION SHOULD BE MOVING INTO EAST/SOUTHEAST CWA DURING MORNING...BUT WITH COLD FRONT ONLY MAKING SLOW PROGRESS AND AIR MASS STILL BEING WARM/MOST...WILL HAVE TO WATCH FOR REGENERATION OF STRONGER CONVECTION IN THE SOUTHEAST DURING THE AFTERNOON INTO THE EARLY EVENING. 850/925 MB TEMPS WILL REMAIN IN TEENS CELSIUS THROUGH AFTN SO HIGHS SHOULD REACH THE LOWER-MID 70S. LONG TERM...FRIDAY NIGHT THROUGH TUESDAY... UNLIKE WHAT WE HAVE SEEN AFTER PREVIOUS WARM SPELLS THIS SPRING...WE DO NOT LOOK TO RETURN TO A MUCH COOLER THAN NORMAL PATTERN AFTER THE PASSAGE OF THE LATE WEEK SYSTEM. THE JET STREAM PATTERN LOOKS TO REMAIN MORE ZONAL...WHICH WILL SUPPORT NORMAL TO SLIGHTLY ABOVE NORMAL TEMPS AND POSSIBLY MORESO AS PER 12Z OPERATIONAL EUROPEAN MODEL EARLY NEXT WEEK. UNCERTAINTY INCREASES IN THE OPERATIONAL AND ENSEMBLE MODELS...BUT IT APPEARS AFTER A PRIMARILY DRY SATURDAY...THE PATTERN COULD BE A BIT UNSETTLED WITH PERIODIC TSRA CHANCES. TIMING IS THE MAIN QUESTION AS THE GFS IS MUCH MORE PROGRESSIVE WITH THE NEXT SYSTEM. AS ALLUDED TO ABOVE...THIS WILL ALSO IMPACT HOW WARM TEMPERATURES GET EARLY NEXT WORK WEEK. CONFIDENCE IS ALSO LOWER ON WHICH DAYS ARE MOST SYNOPTICALLY FAVORABLE FOR ONSHORE FLOW KEEPING AT LEAST PORTIONS OF THE LAKEFRONT MUCH COOLER THAN INLAND. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * ISOLATED TSRA EARLY THIS MORNING NORTH OF ORD. * WARM FRONT AND ASSOCIATED WIND DIRECTIONS/SPEEDS FROM SUNRISE THROUGH LATE AFTERNOON. //DISCUSSION...UPDATED 06Z... ISOLATED THUNDERSTORMS ARE STILL POSSIBLE ACROSS FAR NORTHEAST IA AND FAR NORTHWEST IL THROUGH DAYBREAK AS AN UPPER LEVEL RIDGE BUILDS NORTH ACROSS THE REGION. ANYTHING THAT FORMS WILL LIFT NORTHEAST AND NOT EXPECTING ANY OF THIS ACTIVITY TO REACH THE CHICAGO AREA TERMINALS...REMAINING NORTH OF ORD/DPA. DURATION WILL ALSO BE RATHER SHORT AT RFD...BUT CONFIDENCE FOR TIMING IS LOW SO MAINTAINED CURRENT 08Z-11Z TIMING. DAYLIGHT HOURS TODAY INTO TONIGHT ARE EXPECTED TO BE DRY ACROSS THE ENTIRE AREA. A WARM FRONT CURRENTLY EXTENDS FROM NORTHERN MISSOURI AND ACROSS CENTRAL ILLINOIS AND WILL SLOWLY LIFT NORTH THIS MORNING AND SHOULD REACH THE I-80 CORRIDOR BY LATE MORNING. ITS PROGRESS NORTH COULD BE SLOWED BY THE COLDER AIR OVER LAKE MICHIGAN AND HOW FAST IT ADVANCES NORTH FIRST TO MDW AND THEN TO ORD/DPA IS SOMEWHAT UNCERTAIN AND MAINTAINED CURRENT TIMING FROM PREVIOUS FORECASTS. ITS POSSIBLE THAT THIS FRONTAL BOUNDARY MAY STALL IN AND AROUND ORD/MDW WITH SOME GUIDANCE SHOWING SOUTHERLY WINDS TURNING BACK SOUTHEASTERLY LATE IN THE AFTERNOON. UPDATES/CHANGES TO THIS WIND FORECAST CAN BE EXPECTED AS THE FRONT APPROACHES LATER THIS MORNING INTO THIS AFTERNOON AND TIMING/SPEED BECOMES MORE CERTAIN. CMS //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM ANY TSRA EARLY THIS MORNING WILL REMAIN NORTH OF ORD. * MEDIUM FOR WIND DIRECTIONS/SPEEDS THROUGH SUNRISE...THEN LOW THIS MORNING AND THIS AFTERNOON AS WARM FRONT LIFTS NORTH. CMS //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... * THURSDAY...CHANCE OF TSRA IN THE AFTERNOON. GUSTY SOUTHERLY WINDS. * THURSDAY NIGHT...TSRA LIKELY. * FRIDAY...CHANCE OF TSRA. GUSTY WESTERLY WINDS. * SATURDAY...DRY/VFR. * SUNDAY AND MONDAY...CHANCE OF TSRA. KJB && .MARINE... 302 PM CDT HIGH PRESSURE EXTENDS FROM HUDSON BAY TO THE MID ATLANTIC WHILE LOW PRESSURE REMAINS NEARLY STATIONARY AND SLOWLY DEEPENS OVER THE CENTRAL PLAINS. A WARM FRONT EXTENDING EAST FROM THE LOW...THROUGH THE OHIO VALLEY WILL REMAIN NEARLY STATIONARY...WITH ANY NORTHWARD PROGRESS BLOCKED BY THE HIGH. THIS WILL KEEP BRISK EASTERLY FLOW OVER LAKE MICHIGAN UNTIL THE WARM FRONT CAN PUSH TO THE NORTH. BY LATE WEDNESDAY MORNING...THE HIGH WILL BEGIN TO SLIDE TO THE EAST...ALLOWING THE WARM FRONT TO SURGE NORTHWARD. THE PARENT LOW IS EXPECTED TO TRACK TO THE NORTHEAST AND BECOME ELONGATED THROUGH WEDNESDAY NIGHT AND INTO THURSDAY...WITH THE WARM FRONT REACHING THE FAR NORTH END OF THE LAKE BY THURSDAY AFTERNOON...WITH WINDS TURNING SOUTHERLY. THE WARM FRONT SHOULD FINALLY REACH THE FAR SOUTHERN TIP OF THE LAKE BY LATE WEDNESDAY MORNING...ALLOWING FLOW TO TURN OFFSHORE OF THE INDIANA COAST. THE FRONT SHOULD PUSH SOUTH OF THE ILLINOIS NEARSHORE WATERS BY LATE AFTERNOON...SO WILL NOT MAKE ANY CHANGES TO THE GOING SMALL CRAFT ADVISORY AT THIS TIME. THE SOUTHERLY GRADIENT WILL TIGHTEN THURSDAY INTO EARLY FRIDAY...ALLOWING SOUTHERLY WINDS TO STRENGTHEN...BUT VERY WARM AIR OVERSPREADING THE COLD LAKE WATER SHOULD HELP LIMIT MIXING...ESPECIALLY OVER THE OPEN WATERS. THE NEARSHORE WATERS ARE BEGINNING TO GET A BIT WARMER...SO THERE COULD BE BETTER MIXING THERE AND WIND SPEEDS MAY FLIRT WITH GALE FORCE...BUT FOR NOW...FEEL THAT 30KT SOUTHERLY WINDS SHOULD BE THE PREVAILING CONDITION FOR THURSDAY INTO EARLY FRIDAY AFTERNOON. BY LATE FRIDAY AFTERNOON OR EARLY FRIDAY EVENING...THE LOW WILL TRACK NORTH OF THE GREAT LAKES TO NEAR JAMES BAY. AN ASSOCIATED COLD FRONT WILL SWEEP ACROSS THE LAKE FRIDAY AFTERNOON...TURNING WINDS TO WESTERLY BY FRIDAY EVENING. HIGH PRESSURE WILL THEN BUILD ACROSS THE LAKE BEGINNING FRIDAY NIGHT AND REMAINING IN PLACE INTO SUNDAY MORNING. WHILE THE HIGH PRESSURE RESIDES OVER THE LAKE...WINDS SHOULD BE RELATIVELY LIGHT WITH LAKE BREEZE DEVELOPMENT POSSIBLE. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM WEDNESDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 PM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
548 PM EDT WED MAY 7 2014 .SYNOPSIS... ISSUED AT 547 PM EDT WED MAY 7 2014 A WARM FRONT WILL CONTINUE TO SHIFT NORTH THROUGH LOWER MICHIGAN TONIGHT. ANY SHOWERS AND THUNDERSTORMS ARE EXPECTED TO REMAIN WELL NORTH OF THE FRONT...WHICH SHOULD RESULT IN DRY CONDITIONS ACROSS OUR AREA TONIGHT. LOWS OVERNIGHT WILL RANGE FROM THE MID 50S OVER SOUTHEAST MICHIGAN AND NORTHWEST OHIO TO THE MID 60S OVER CENTRAL INDIANA. SUNNY TO PARTLY CLOUDY SKIES SHOULD ALLOW HIGH TEMPERATURES TO REACH WELL INTO THE MID 80S THROUGHOUT THE AREA THURSDAY. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 352 PM EDT WED MAY 7 2014 NEAR TERM FOCUS ON WIDELY SCT TSTMS ACROSS N ILLINOIS WITH WEAKER SHOWERS COMING ACROSS SOUTHERN LK MI. ILLINOIS ACTIVITY WAS BEING ENHANCED TO SOME DEGREE BY NE MOVING SHORT WAVE WHICH WILL PASS ACROSS THE AREA INTO THIS EVENING. STEEP MID LEVEL LAPSE RATES WERE IN PLACE ACROSS THE REGION...BUT STRONG ELEVATED MIXED LAYER WAS PREVENTING MORE WIDESPREAD DEVELOPMENT. ACTIVITY MOVING ACROSS THE LAKE WAS WEAKENING AS IT MOVES EAST. WARM FRONT HAS BEEN SURGING NORTH MUCH OF THE DAY WITH SW HALF OF THE AREA NOW IN THE UPR 70S TO LOW 80S. KIWX 88D APPEARS TO BE SHOWING THIS FEATURE WHICH LOOKS TO BE QUASI STATIONARY ALONG ROUTE 30. WOULD EXPECT THIS TO GET MOVING AGAIN ONCE THE SHORT WAVE PUSHES THROUGH. FOR NOW WILL HAVE A DRY FORECAST WITH EVE SHIFT TO MONITOR TRENDS FOR ADDITION OF ISOLATED CONVECTION UNTIL SUNSET. LOW LEVEL MSTR WILL CONTINUE TO PUSH INTO THE REGION TONIGHT WITH A BALMY EARLY MAY NIGHT IN STORE WITH LOWS A GOOD 10 TO 15 DEGREES ABOVE NORMAL RANGING FROM THE MID 50S TO LOW 60S. SEVERAL OF THE HIGH RES MODELS HAVE BEEN TRYING TO DEVELOP A STRATUS DECK ACROSS MUCH OF THE AREA AS COOLING TAKES PLACE. WHILE SETUP CAN`T BE FULLY DISMISSED...THINK MODELS ARE GETTING A BIT CARRIED AWAY WITH IT AT THIS POINT. IF ON THE OTHER HAND THE FRONTAL BOUNDARY REMAINS STALLED IN THE AREA...THEN A GREATER LIKELIHOOD OF LOW CLOUDS WOULD EXIST. STILL HOLDING WITH MOSTLY CLEAR/PARTLY CLOUDY SKIES TONIGHT. THURSDAY SHOULD BE WARM AND UNSTABLE AS TEMPS SOAR INTO THE LOW TO MID 80S. SFC BASED INSTABILITY WILL EXIST...BUT LACK OF TRIGGER AND STRONG EML STILL IN PLACE TO PRECLUDE ALL BUT SOME CU DEVELOPMENT. && .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 352 PM EDT WED MAY 7 2014 NORTHWARD LOW LEVEL MOISTURE TRANSPORT TO COMMENCE THURSDAY NIGHT VIA A 50 KNOT SOUTHERLY LOW LEVEL JET. SEVERAL WEAK MID/UPPER PERTURBATIONS WILL LIKELY TRACK INTO THE OHIO VALLEY/WESTERN GREAT LAKES REGION DURING THIS TIME. ELEVATED MIXED LAYER WILL LIKELY LIMIT ANY CONVECTION FOR MOST OF THE THURSDAY NIGHT PERIOD. CORFIDI VECTORS SHOULD TEND TO BECOME MORE SOUTHWESTERLY LATE THURSDAY NIGHT POSSIBLY FAVORING EASTWARD PROPAGATION OF IL CONVECTION INTO WESTERN PORTIONS OF THE AREA TOWARD FRIDAY MORNING. A FAIRLY STRONG WEST TO EAST ORIENTED MUCAPE GRADIENT SHOULD EXIST ACROSS THE REGION HOWEVER...SO SOME QUESTION AS TO WHAT PROPAGATION MODE THIS CONVECTION WILL TAKE. HAVE NOT MADE SIGNIFICANT CHANGES TO PREVIOUS POP FORECAST THURSDAY NIGHT...CONFINING OVERNIGHT LIKELY POPS TO THE FAR WEST. PRIMARY LOW LEVEL MOISTURE TONGUE WILL ADVECT INTO THE REGION EARLY FRIDAY...AIDED BY BROAD SYNOPTIC SCALE PRE-FRONTAL LOW LEVEL CONFLUENCE. THIS SHOULD SUPPORT EASTWARD EXPANSION OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS IN THE MORNING. CONFIDENCE IN FRIDAY AFTERNOON CONVECTIVE POTENTIAL STILL SOMEWHAT MUDDLED BY INFLUENCES OF MORNING PRECIP. MODELS ALSO STILL EXHIBITING SOME SIGNIFICANT DIFFERENCES IN TERMS OF TIMING NEXT PV ANOMALY TO LIFT INTO THE GREAT LAKES REGION SOME TIME LATE FRIDAY AFTERNOON/NIGHT. EXIT REGION OF 120 KNOT UPPER JET STREAK SHOULD ALSO ENHANCE SYNOPTIC SCALE LIFT BY FRIDAY EVENING...SUPPORTING ADDITIONAL CONVECTIVE DEVELOPMENT ALONG MAIN COLD FRONTAL BOUNDARY. ENHANCED DEEP LAYER SHEAR ASSOCIATED WITH THIS POCKET OF STRONGER UPPER FLOW...AND MORE LIKELY POSITION OF PRIMARY INSTABILITY AXIS ACROSS WESTERN PORTIONS OF FORECAST AREA LATE FRIDAY AFTERNOON/EARLY FRIDAY EVENING...MAY LEND TO A SMALL WINDOW OF SEVERE POTENTIAL DURING THIS PERIOD. AFOREMENTIONED PV ANOMALY TO BECOME MORE INFLUENCED BY UPPER LEVEL DEFORMATION FLOW AS IT LIFTS NORTHEASTWARD ACROSS THE GREAT LAKES/SOUTHERN ONTARIO WHICH SHOULD TEND TO SLOW EASTWARD FRONTAL PROGRESSION LATE FRIDAY NIGHT/EARLY SATURDAY. FRONTAL CONVERGENCE SHOULD TEND TO WEAKEN AS THIS OCCURS...SO WOULD EXPECT DIMINISHING COVERAGE DURING THE OVERNIGHT HOURS. HAVE MAINTAINED LOW CHANCE POPS ACROSS FAR SOUTHEAST SATURDAY DUE TO SLOWING NATURE OF BOUNDARY...BUT GREATER CONFIDENCE IN NEXT ROUND OF PRECIP SHOULD HOLD OFF UNTIL LATE SATURDAY NIGHT AS LOW LEVEL ISENTROPIC UPGLIDE COMMENCES OVER THIS BOUNDARY...PARTICULARLY ACROSS WESTERN PORTIONS OF THE AREA. DISTURBED SOUTHWESTERLY UPPER FLOW IN ADVANCE OF NEXT MORE SIGNIFICANT UPPER TROUGH ACROSS WESTERN CONUS WILL PROVIDE AT LEAST CHANCE OF SHOWERS/STORMS THROUGH MUCH OF THE LATE WEEKEND THROUGH EARLY NEXT PERIOD. HOWEVER...SOME SUBSTANTIAL MEDIUM RANGE MODEL DIFFERENCES PERSIST REGARDING PHASING THIS WESTERN CONUS TROUGH WITH SOUTH CENTRAL CANADIAN UPPER LOW. EC/GEM REMAIN MUCH SLOWER AND BETTER PHASED...WHILE GFS IS MUCH MORE PROGRESSIVE AND LESS PHASED...TAKING COLD FRONTAL BOUNDARY EAST OF THE AREA MONDAY NIGHT. AT THIS FORECAST DISTANCE WITH LARGE DETERMINISTIC/ENSEMBLE SPREADS...HAVE NOT STRAYED FAR FROM CONSENSUS APPROACH OF CRALLBLEND WHICH PROVIDES COMPROMISE IN TIMING OF THESE TWO CAMPS. OF HIGHER CONFIDENCE IS ANOTHER WARMING TREND LATE WEEKEND INTO MONDAY IN ADVANCE OF THIS SYSTEM...WITH HIGHS FROM MID 70S TO AROUND 80 POSSIBLE AGAIN BY SUNDAY. COOLER CONDITIONS EXPECTED ACROSS PORTIONS OF SOUTHWEST LOWER MICHIGAN WITH SWRLY LOW LEVEL COMPONENT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 144 PM EDT WED MAY 7 2014 WARM FRONT WAS CLEARING KFWA AND WILL ARRIVE AT KSBN SHORTLY ALLOWING FOR SOUTHERLY FLOW TO SET UP. MID/HIGH CLOUDS ABOUT ALL THAT IS AROUND FOR THE TIME BEING. WILL BE MONITORING CONVECTION DEVELOPING ACROSS CENTRAL ILLINOIS THAT COULD DRIFT INTO THE AREA LATER THIS AFTERNOON/EVE. SETUP NOT THE MOST FAVORABLE SO NO MENTION IN TAFS. OTHERWISE...INCREASE IN LL MSTR WILL TAKE PLACE TONIGHT WITH MANY OF THE HIGH RES MODELS SUGGESTING STRATUS DEVELOPING (SOME HINTS AT EVEN IFR CIGS). NOT READY TO BUY THIS YET WITH RUC STILL SHOWING GENERALLY CLEAR CONDITIONS SO WILL MAINTAIN PREV FORECAST. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...FISHER/KG SHORT TERM...FISHER LONG TERM...MARSILI AVIATION...FISHER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
353 PM EDT WED MAY 7 2014 .SYNOPSIS... ISSUED AT 152 PM EDT WED MAY 7 2014 A WARM FRONT SHIFT QUICKLY NORTH INTO LOWER MICHIGAN BY TONIGHT. THUNDERSTORMS ARE EXPECTED TO REMAIN WELL NORTH OF THE FRONT... WHICH SHOULD RESULT IN DRY CONDITIONS ACROSS OUR AREA TODAY AND TONIGHT. TEMPERATURES WILL BE WARMER... WITH HIGHS TODAY IN THE 70S OVER SOUTHERN MICHIGAN AND NORTHERN PORTIONS OF NORTHWEST OHIO... AND IN THE LOWER TO MIDDLE 80S OVER THE REST OF THE AREA. LOWS TONIGHT WILL RANGE FROM THE MID 50S OVER SOUTHEAST MICHIGAN AND NORTHWEST OHIO TO THE MID 60S OVER CENTRAL INDIANA. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 352 PM EDT WED MAY 7 2014 NEAR TERM FOCUS ON WIDELY SCT TSTMS ACROSS N ILLINOIS WITH WEAKER SHOWERS COMING ACROSS SOUTHERN LK MI. ILLINOIS ACTIVITY WAS BEING ENHANCED TO SOME DEGREE BY NE MOVING SHORT WAVE WHICH WILL PASS ACROSS THE AREA INTO THIS EVENING. STEEP MID LEVEL LAPSE RATES WERE IN PLACE ACROSS THE REGION...BUT STRONG ELEVATED MIXED LAYER WAS PREVENTING MORE WIDESPREAD DEVELOPMENT. ACTIVITY MOVING ACROSS THE LAKE WAS WEAKENING AS IT MOVES EAST. WARM FRONT HAS BEEN SURGING NORTH MUCH OF THE DAY WITH SW HALF OF THE AREA NOW IN THE UPR 70S TO LOW 80S. KIWX 88D APPEARS TO BE SHOWING THIS FEATURE WHICH LOOKS TO BE QUASI STATIONARY ALONG ROUTE 30. WOULD EXPECT THIS TO GET MOVING AGAIN ONCE THE SHORT WAVE PUSHES THROUGH. FOR NOW WILL HAVE A DRY FORECAST WITH EVE SHIFT TO MONITOR TRENDS FOR ADDITION OF ISOLATED CONVECTION UNTIL SUNSET. LOW LEVEL MSTR WILL CONTINUE TO PUSH INTO THE REGION TONIGHT WITH A BALMY EARLY MAY NIGHT IN STORE WITH LOWS A GOOD 10 TO 15 DEGREES ABOVE NORMAL RANGING FROM THE MID 50S TO LOW 60S. SEVERAL OF THE HIGH RES MODELS HAVE BEEN TRYING TO DEVELOP A STRATUS DECK ACROSS MUCH OF THE AREA AS COOLING TAKES PLACE. WHILE SETUP CAN`T BE FULLY DISMISSED...THINK MODELS ARE GETTING A BIT CARRIED AWAY WITH IT AT THIS POINT. IF ON THE OTHER HAND THE FRONTAL BOUNDARY REMAINS STALLED IN THE AREA...THEN A GREATER LIKELIHOOD OF LOW CLOUDS WOULD EXIST. STILL HOLDING WITH MOSTLY CLEAR/PARTLY CLOUDY SKIES TONIGHT. THURSDAY SHOULD BE WARM AND UNSTABLE AS TEMPS SOAR INTO THE LOW TO MID 80S. SFC BASED INSTABILITY WILL EXIST...BUT LACK OF TRIGGER AND STRONG EML STILL IN PLACE TO PRECLUDE ALL BUT SOME CU DEVELOPMENT. && .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 352 PM EDT WED MAY 7 2014 NORTHWARD LOW LEVEL MOISTURE TRANSPORT TO COMMENCE THURSDAY NIGHT VIA A 50 KNOT SOUTHERLY LOW LEVEL JET. SEVERAL WEAK MID/UPPER PERTURBATIONS WILL LIKELY TRACK INTO THE OHIO VALLEY/WESTERN GREAT LAKES REGION DURING THIS TIME. ELEVATED MIXED LAYER WILL LIKELY LIMIT ANY CONVECTION FOR MOST OF THE THURSDAY NIGHT PERIOD. CORFIDI VECTORS SHOULD TEND TO BECOME MORE SOUTHWESTERLY LATE THURSDAY NIGHT POSSIBLY FAVORING EASTWARD PROPAGATION OF IL CONVECTION INTO WESTERN PORTIONS OF THE AREA TOWARD FRIDAY MORNING. A FAIRLY STRONG WEST TO EAST ORIENTED MUCAPE GRADIENT SHOULD EXIST ACROSS THE REGION HOWEVER...SO SOME QUESTION AS TO WHAT PROPAGATION MODE THIS CONVECTION WILL TAKE. HAVE NOT MADE SIGNIFICANT CHANGES TO PREVIOUS POP FORECAST THURSDAY NIGHT...CONFINING OVERNIGHT LIKELY POPS TO THE FAR WEST. PRIMARY LOW LEVEL MOISTURE TONGUE WILL ADVECT INTO THE REGION EARLY FRIDAY...AIDED BY BROAD SYNOPTIC SCALE PRE-FRONTAL LOW LEVEL CONFLUENCE. THIS SHOULD SUPPORT EASTWARD EXPANSION OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS IN THE MORNING. CONFIDENCE IN FRIDAY AFTERNOON CONVECTIVE POTENTIAL STILL SOMEWHAT MUDDLED BY INFLUENCES OF MORNING PRECIP. MODELS ALSO STILL EXHIBITING SOME SIGNIFICANT DIFFERENCES IN TERMS OF TIMING NEXT PV ANOMALY TO LIFT INTO THE GREAT LAKES REGION SOME TIME LATE FRIDAY AFTERNOON/NIGHT. EXIT REGION OF 120 KNOT UPPER JET STREAK SHOULD ALSO ENHANCE SYNOPTIC SCALE LIFT BY FRIDAY EVENING...SUPPORTING ADDITIONAL CONVECTIVE DEVELOPMENT ALONG MAIN COLD FRONTAL BOUNDARY. ENHANCED DEEP LAYER SHEAR ASSOCIATED WITH THIS POCKET OF STRONGER UPPER FLOW...AND MORE LIKELY POSITION OF PRIMARY INSTABILITY AXIS ACROSS WESTERN PORTIONS OF FORECAST AREA LATE FRIDAY AFTERNOON/EARLY FRIDAY EVENING...MAY LEND TO A SMALL WINDOW OF SEVERE POTENTIAL DURING THIS PERIOD. AFOREMENTIONED PV ANOMALY TO BECOME MORE INFLUENCED BY UPPER LEVEL DEFORMATION FLOW AS IT LIFTS NORTHEASTWARD ACROSS THE GREAT LAKES/SOUTHERN ONTARIO WHICH SHOULD TEND TO SLOW EASTWARD FRONTAL PROGRESSION LATE FRIDAY NIGHT/EARLY SATURDAY. FRONTAL CONVERGENCE SHOULD TEND TO WEAKEN AS THIS OCCURS...SO WOULD EXPECT DIMINISHING COVERAGE DURING THE OVERNIGHT HOURS. HAVE MAINTAINED LOW CHANCE POPS ACROSS FAR SOUTHEAST SATURDAY DUE TO SLOWING NATURE OF BOUNDARY...BUT GREATER CONFIDENCE IN NEXT ROUND OF PRECIP SHOULD HOLD OFF UNTIL LATE SATURDAY NIGHT AS LOW LEVEL ISENTROPIC UPGLIDE COMMENCES OVER THIS BOUNDARY...PARTICULARLY ACROSS WESTERN PORTIONS OF THE AREA. DISTURBED SOUTHWESTERLY UPPER FLOW IN ADVANCE OF NEXT MORE SIGNIFICANT UPPER TROUGH ACROSS WESTERN CONUS WILL PROVIDE AT LEAST CHANCE OF SHOWERS/STORMS THROUGH MUCH OF THE LATE WEEKEND THROUGH EARLY NEXT PERIOD. HOWEVER...SOME SUBSTANTIAL MEDIUM RANGE MODEL DIFFERENCES PERSIST REGARDING PHASING THIS WESTERN CONUS TROUGH WITH SOUTH CENTRAL CANADIAN UPPER LOW. EC/GEM REMAIN MUCH SLOWER AND BETTER PHASED...WHILE GFS IS MUCH MORE PROGRESSIVE AND LESS PHASED...TAKING COLD FRONTAL BOUNDARY EAST OF THE AREA MONDAY NIGHT. AT THIS FORECAST DISTANCE WITH LARGE DETERMINISTIC/ENSEMBLE SPREADS...HAVE NOT STRAYED FAR FROM CONSENSUS APPROACH OF CRALLBLEND WHICH PROVIDES COMPROMISE IN TIMING OF THESE TWO CAMPS. OF HIGHER CONFIDENCE IS ANOTHER WARMING TREND LATE WEEKEND INTO MONDAY IN ADVANCE OF THIS SYSTEM...WITH HIGHS FROM MID 70S TO AROUND 80 POSSIBLE AGAIN BY SUNDAY. COOLER CONDITIONS EXPECTED ACROSS PORTIONS OF SOUTHWEST LOWER MICHIGAN WITH SWRLY LOW LEVEL COMPONENT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 144 PM EDT WED MAY 7 2014 WARM FRONT WAS CLEARING KFWA AND WILL ARRIVE AT KSBN SHORTLY ALLOWING FOR SOUTHERLY FLOW TO SET UP. MID/HIGH CLOUDS ABOUT ALL THAT IS AROUND FOR THE TIME BEING. WILL BE MONITORING CONVECTION DEVELOPING ACROSS CENTRAL ILLINOIS THAT COULD DRIFT INTO THE AREA LATER THIS AFTERNOON/EVE. SETUP NOT THE MOST FAVORABLE SO NO MENTION IN TAFS. OTHERWISE...INCREASE IN LL MSTR WILL TAKE PLACE TONIGHT WITH MANY OF THE HIGH RES MODELS SUGGESTING STRATUS DEVELOPING (SOME HINTS AT EVEN IFR CIGS). NOT READY TO BUY THIS YET WITH RUC STILL SHOWING GENERALLY CLEAR CONDITIONS SO WILL MAINTAIN PREV FORECAST. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...MARSILI AVIATION...FISHER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
152 PM EDT WED MAY 7 2014 .SYNOPSIS... ISSUED AT 152 PM EDT WED MAY 7 2014 A WARM FRONT SHIFT QUICKLY NORTH INTO LOWER MICHIGAN BY TONIGHT. THUNDERSTORMS ARE EXPECTED TO REMAIN WELL NORTH OF THE FRONT... WHICH SHOULD RESULT IN DRY CONDITIONS ACROSS OUR AREA TODAY AND TONIGHT. TEMPERATURES WILL BE WARMER... WITH HIGHS TODAY IN THE 70S OVER SOUTHERN MICHIGAN AND NORTHERN PORTIONS OF NORTHWEST OHIO... AND IN THE LOWER TO MIDDLE 80S OVER THE REST OF THE AREA. LOWS TONIGHT WILL RANGE FROM THE MID 50S OVER SOUTHEAST MICHIGAN AND NORTHWEST OHIO TO THE MID 60S OVER CENTRAL INDIANA. && .UPDATE... ISSUED AT 144 PM EDT WED MAY 7 2014 FORECAST REMAINS ON TRACK FOR THE TIME BEING WITH WARM FRONT MAKING PROGRESS NORTH ACROSS THE AREA. OBSERVATIONS INDICATE A LOCATIONS SOMEWHERE ALONG OR JUST NORTH OF ROUTE 30 WITH A RAPID JUMP INTO THE 70S TO NEAR 80 SOUTH IT AND TEMPS WELL NE OF THE BOUNDARY STILL IN THE LOWER 60S. AS MENTIONED IN PREV UPDATE...EYES WOULD BE FOCUSED ON CENTRAL ILLINOIS BASED ON SOME OF THE HIGH RES MODELS INDICATING POSSIBLE WIDELY SCT CONVECTION AS MISSOURI SHORT WAVE MOVES NE. RADAR TRENDS OVER THE LAST HALF HOUR HAVE SHOWN NEW DEVELOPMENT FROM OVER THE KILX SITE NW...WITH THIS MOVING NNE. THIS ACTIVITY IS WELL SOUTH OF THE WARM FRONT...BUT MAY STILL BE SOMEWHAT ELEVATED GIVEN EML IN PLACE. REGARDLESS...ADDITIONAL MONITORING WILL BE NEEDED ACROSS THIS AREA FOR POSSIBLE WIDELY SCT CONVECTION LATER THIS AFTERNOON. WILL MAINTAIN DRY FORECAST FOR NOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 458 AM EDT WED MAY 7 2014 HIGH PRESSURE OVER SE CANADA WILL CONTINUE TO MOVE SLOWLY EAST TODAY ALLOWING WARM FRONT OVER KY AND SRN IN/IL TO LIFT NORTH TO THE MI/IN-OH BORDER. BAND OF SHOWERS/TSTMS WHICH DEVELOPED IN THE STRONG THETA-E ADVECTION REGIME NORTH OF THIS WARM FRONT FROM WI SEWD INTO NW OH EARLY THIS MORNING WAS MOVG SLOWLY EAST WITH SOME BACKBUILDING. THUS, THE THREAT OF CONVECTION CONTS ACROSS THE NE PORTION OF THE CWA EARLY THIS MORNING... BUT EXPECT IT WILL END BY 12Z SO HAVE A PRE-FIRST PERIOD IN THE ZFP TO HANDLE ONGOING ACTIVITY. REST OF THE DAY SHOULD BE RAIN-FREE ACROSS OUR AREA AS WARM AND RELATIVELY DRY AIRMASS EVIDENT ON ILX`S 00Z SOUNDING OVERSPREADS OUR CWA. IR SATELLITE IMAGERY SUGGESTS CONSIDERABLE HIGH CLOUDINESS OVER OUR AREA AND UPSTREAM ACROSS IL/MO AND INTO THE SRN PLAINS. EXPECT PARTLY SUNNY SKIES ACROSS OUR AREA TODAY WITH MAINLY HIGH CLOUDINESS. TEMPS SHOULD RESPOND TO THE WARM FRONT MOVING NORTH WITH HIGHS IN THE L-M80S OVER THE AREA EXCEPT ONLY IN THE 70S OVER SRN MI AND NRN PORTIONS OF NW OH WHICH SHOULD REMAIN NORTH OF THE FRONT. WARM FRONT SHOULD CONT TO LIFT SLOWLY NORTH ACROSS LWR MI TONIGHT AS A STRONG SHRTWV LIFTS NE AHEAD OF ROCKIES TROF CAUSING STNRY SFC LOW OVER THE CENTRAL PLAINS TO LIFT NE TO ERN SD. CONVECTION SHOULD AGAIN BE WELL NORTH OF THE FRONT AS AIRMASS TO THE SOUTH REMAINS RELATIVELY DRY. THUS, CONTD DRY FCST FOR TONIGHT IN OUR AREA WITH MILD LOWS RANGING FROM THE M50S NE TO THE M60S SW. && .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 458 AM EDT WED MAY 7 2014 VERY WARM TEMPERATURES ON TRACK FOR THURSDAY WITH 850 MB TEMPS APPROACHING 20C PER LATEST 12KM/NAM. RAISED HIGHS A LITTLE TO COME IN LINE WITH THE GFS/MAV WHICH APPEARS ON TRACK WITH HIGHS APPROACHING RECORDS IN THE UPPER 80S AT FT WAYNE. THE FRONT WILL MOVE ACROSS THE AREA FRIDAY/FRIDAY NIGHT. THE GFS AND ECMWF HAVE COME INTO VERY GOOD AGREEMENT WITH THE TIMING OF THE FRONT...SO HAVE ADJUSTED RAIN/STORM CHANCES ACCORDINGLY. THE BEST CHANCE FOR SEVERE STORMS APPEARS TO BE OVER NORTHERN INDIANA LATE FRIDAY AFTERNOON INTO EARLY FRIDAY NIGHT AHEAD OF THE FRONT WHERE LOW LEVEL CONVERGENCE ALONG THE FRONT COMBINED WITH THE RIGHT ENTRANCE REGION OF THE JET MAY ALLOW SOME STORMS TO BECOME SEVERE. OTHERWISE... TEMPERATURES WILL BE COOLING BACK TO NORMAL FOR THE REST OF THE PERIOD. THE GFS AND ECMWF RUN TO RUN CONSISTENCY CONTINUES TO BE POOR LATE IN THE EXTENDED PERIOD...SO TRIED TO KEEP THE ONGOING FORECAST WITHOUT MAKING MANY CHANGES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 144 PM EDT WED MAY 7 2014 WARM FRONT WAS CLEARING KFWA AND WILL ARRIVE AT KSBN SHORTLY ALLOWING FOR SOUTHERLY FLOW TO SET UP. MID/HIGH CLOUDS ABOUT ALL THAT IS AROUND FOR THE TIME BEING. WILL BE MONITORING CONVECTION DEVELOPING ACROSS CENTRAL ILLINOIS THAT COULD DRIFT INTO THE AREA LATER THIS AFTERNOON/EVE. SETUP NOT THE MOST FAVORABLE SO NO MENTION IN TAFS. OTHERWISE...INCREASE IN LL MSTR WILL TAKE PLACE TONIGHT WITH MANY OF THE HIGH RES MODELS SUGGESTING STRATUS DEVELOPING (SOME HINTS AT EVEN IFR CIGS). NOT READY TO BUY THIS YET WITH RUC STILL SHOWING GENERALLY CLEAR CONDITIONS SO WILL MAINTAIN PREV FORECAST. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...FISHER SYNOPSIS...JT SHORT TERM...JT LONG TERM...SKIPPER AVIATION...FISHER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1007 PM CDT Thu May 8 2014 ...UPDATE TO SYNOPSIS... .SYNOPSIS... ISSUED AT 1007 PM CDT THU MAY 8 2014 Water vapor imagery and 00Z upper air analysis indicate an upper level trough axis transitioning eastward across the Western High Plains. Meanwhile, another upper level trough is pushing ashore into the Pacific Northwest. Near the surface...a cold front extends from northeastern Kansas southwest into western Oklahoma while high pressure builds across the Northern Plains. Cool dry air is filtering southward into western Kansas with surface dewpoints falling into the 30s(F). && .SHORT TERM...(This evening through Friday) ISSUED AT 329 PM CDT THU MAY 8 2014 Chances are greatest that most of the forecast area remains dry tonight. The front has shifted far enough east that the HRRR model solutions appear more believable than the NAM model`s solution of a retreating dryline returning moisture and allowing moist deep convection. The far west central Kansas counties such as Hamilton and Stanton could see showers and isolated thunderstorms early this evening associated with convective development over eastern Colorado. Of the various HiRes models, the NMM cores suggest a PV anomaly significant enough to produce showers on the backside of the upper jet, mainly late tonight and overnight. Instability will be minimal however and probabilities have been kept very low for the overnight episode. Temperatures overnight should fall into the low 50s and seen some 40s farther west where clearing is likely by 12 UTC. Weak westerly downslope surface winds will develop on Friday as surface high pressure spreads eastward across southeast Kansas during the afternoon. Other than mid level clouds, mostly sunny conditions should prevail based on model layer RH fields. The downslope flow will promote adiabatic warming resulting in boundary layer warm advection. Models are strongly aligned for highs in the mid to upper 70s with only bias corrected solutions creating warmer highs in the low 80s in the far southwest. .LONG TERM...(Friday night through Thursday) ISSUED AT 314 PM CDT THU MAY 8 2014 The medium range models continue to show a strong upper level shortwave digging into the western states this weekend and moving out into the plains by early next week. The ECMWF, GEM and UKMET models have all been similar and tend to be slower and deeper with this wave. The GFS has been more open and progressive with this wave for several runs. However, it is showing a tendency in its operational run...as well as some of the ensemble members...to be a little slower and deeper. Upper level westerly flow over the central High Plains on Friday will gradually become more southwesterly by Saturday night as the upper wave digs into the Intermountain West. As the upper wave approaches on Sunday, a frontal boundary should moves southward into western Kansas with a surface low pressure system developing along the front. There are some model differences in the position of this front during the day Sunday. The faster GFS has it through all of western Kansas by later in the afternoon while the other models keep it farther west. This will have significant impacts on daytime high temperatures as well as where the best chance for thunderstorms will be. Given the model tendencies, will keep the front farther west with a fairly significant temperature gradient across southwest and south central Kansas. The models show 60 degree dewpoints spreading northward into the central Plains ahead of this front. We could see an outbreak of severe storms along the front during the later afternoon and early evening hours as stronger southwesterly flow aloft moves into western Kansas. Chances for showers and thunderstorms will linger into Monday as the upper trough continues to move out into the Plains but we should be drying out by Monday night and Tuesday as the upper wave continues east. Temperatures in Monday-Wednesday time period will be fairly cool given the 850 millibar temperatures in the single digits. Temperatures should moderate through the remainder of the extended period as upper level heights build over the western and central U.S. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 629 PM CDT THU MAY 8 2014 VFR conditions will prevail with a few high clouds. Winds will generally be from the north around 10 knots. && .PRELIMINARY POINT TEMPS/POPS... DDC 45 78 48 82 / 20 0 0 0 GCK 43 80 47 81 / 20 0 0 0 EHA 44 80 50 85 / 30 0 0 0 LBL 45 80 48 86 / 20 0 0 0 HYS 43 78 48 80 / 10 0 0 0 P28 50 78 53 86 / 30 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJohnson SHORT TERM...Russell LONG TERM...Gerard AVIATION...Hovorka_42
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1002 PM CDT Thu May 8 2014 .UPDATE... Issued at 1002 PM CDT THU MAY 8 2014 The cold front has started moving east once again and thunderstorm development has recommenced, likely due to increased low level convergence and possibly a weak wave lifting north along the KS/MO state line. Thinking is that instability has weakened from previous convection and cooling of the boundary layer. Because of this we have allowed the watch to expire thinking the chances for widespread severe weather will continue to diminish as the boundary layer cools. Latest radar data suggest there could be some small hail with the stronger updrafts, so we`ll have to continue monitoring storms for a little while longer. Latest water vapor imagery continues to show another shortwave now moving into southwest KS. This wave may help some scattered showers and thunderstorm activity to form late tonight over east central KS. Because of this have continued with some chance pops mainly south of I-70. UPDATE Issued at 634 PM CDT THU MAY 8 2014 Think the cold front will continue to make steady progress east, however outflow from recent convection seems to have masked the true front. The latest RAP and HRRR suggest the stronger convection could be east of the forecast area by 01Z and have trended the forecast in this direction. As the front makes clear progress east, will continue to clear out counties from the watch. Main hazard remains large hail, although available instability only around 1000 J/kg seems to be limiting the storms ability to maintain an updraft. Low level shear parameters do not look very supportive for much of a tornado threat. && .SHORT TERM...(Through Tonight) Issued at 252 PM CDT THU MAY 8 2014 The main focus for the short term is on the potential for thunderstorm development, with some strong to severe storms possible. Water vapor imagery showed the deep mid-level trough progressing eastward into the High Plains with a swath of dry air stretching across the western half of Kansas and the cloud cover gradually diminishing across eastern Kansas. The main surface low was situated over eastern Nebraska, with a secondary low developing over western Oklahoma near the Texas panhandle. As of 19z, the radar and surface obs showed the cold front stretching between these surface lows being located generally along a line from Seneca to Alma to Council Grove. Dewpoints ahead of this boundary where still in the low/mid 60s, with drier conditions settling in behind the boundary as dewpoints dropped into the upper 40s to upper 50s across north central Kansas. The cloud cover along with veering winds behind the front have limited afternoon heating with temperatures generally in the 70s. At 19z, radar showed a few showers and thunderstorms beginning to initiate along this boundary over far eastern/southeast Nebraska. Short-range models show this development continuing to spread southward along the boundary into northeast and eastern Kansas after 20z with more scattered storm development by the 22z-00z time frame, progressing eastward into Missouri during the evening hours. This region looks to be favorable for the development of strong to severe supercell thunderstorms as there is limited convective inhibition in place. MUCAPE is modest with upwards of 1000-2000 J/kg, and there is decent 0-6km bulk shear of 50-60kts. With the frontal passage, soundings show some veering of the low-level winds with 0-1km bulk shear potentially upwards of 15-20kts, so cannot rule out the potential for a few isolated tornadoes across far eastern Kansas. However, the main severe threat looks to be large hail with upwards of golfball size hail possible with the stronger storms. Could also see some damaging winds with this activity. These thunderstorms should initially be somewhat scattered in nature, and develop more into a line of storms by early this evening as the cold front progresses eastward, with this main thunderstorm activity diminishing by mid to late evening. However, additional shower and thunderstorm develop is possible overnight across east central Kansas as the secondary low tracks northeastward into southeast Kansas. Expect these storms to be elevated in nature and should exit east of the area Friday morning. Winds will continue to veer to the west and northwest behind the front tonight into Friday morning, with clearing skies across much of the northwestern half of the forecast area overnight. As a result, expect to see a spread in low temperatures tonight ranging from the middle 40s over north central Kansas to the middle 50s across east central Kansas due to the lingering shower and thunderstorm activity. .LONG TERM...(Friday through Thursday) Issued at 252 PM CDT THU MAY 8 2014 All indications are that the main PV anomaly/trough axis will exit the forecast area by around 15Z on Friday with a few lingering showers or even a thunderstorm possible through that time. Otherwise, expect downward motion and some dry advection to bring sunshine by afternoon. The post-frontal airmass is substantially cooler, but expect to mix up to 850 or even 800 hPa with sunshine and westerly winds, and still expect highs to climb into the 70s. Nearly zonal upper flow prevails into early Saturday with the front weakening and stalling over southern KS or northern OK. Should see dry conditions through Friday night and much of Saturday but expect the front to return north with warm moist advection Friday night into Saturday morning as surface low pressure develops from eastern Colorado into the OK panhandle. So have gone warmer with Friday night lows, and also a bit warmer on Saturday as cloud cover should be limited and the airmass rather warm. By Saturday afternoon, expect a negatively tilted short wave trough to eject across the Dakotas. This storm system will have a glancing impact on the local forecast area, but this bit of ascent will combine with moderate to strong instability expected by Saturday afternoon, along with a frontal boundary that will likely be lingering in the area or drifting back south across parts of Kansas. Expect the cap to be erased by mid to late afternoon, and the instability in conjunction with 30 to 50 kts of 0-6 km wind shear should result in scattered thunderstorms developing near the front. The most likely area seems to be near/south of I-70 at this time, and some of these storms would likely take on supercell characteristics with at least some potential for large hail. The wind potential will at least partially be tied to how warm temperatures get in the warm sector...warmer equating to greater damaging wind potential. Tornado potential seems on the low side given current forecast parameters given expectation for somewhat veered low level winds...but with a nearly stationary front in play, some small potential may exist. Expect a weak embedded short wave trough to perhaps enhance thunderstorm coverage near and even north of the front as the low level jet intensifies after sunset. This could allow the hail threat to persist north of the front through the overnight hours with elevated convection. On Sunday, expect a deep upper trough to begin to eject into the central Plains. The surface low is expected to deepen markedly over the OK panhandle while the surface front should remain across the local forecast area. One of the most significant uncertainties in the Sunday forecast regards the location of the front. The ECMWF is strongest/farthest north with the surface low and hence has the front extending across north central KS. The NAM...which can be flaky with details at the end of the forecast run...is stronger with the cold front progression and has the boundary along the boundary by 00Z Monday. The GFS is playing middle ground at this time. Another area of uncertainty lies in any stabilization that may occur with any overnight/early morning convection as we`ve seen with recent events. Wherever the boundary is located by Sunday afternoon, the warm sector south of the front should be characterized by strong to extreme instability and ample deep layer wind shear. Thunderstorms are likely to develop by mid afternoon along the front and become supercellular and severe. Low level winds again appear to be veered a bit but still with a fair amount of low level shear. All told, this appears to be an elevated chance for severe storms along and south of the frontal boundary...again focused near/south of I-70 for highest chances. The extent of storm severity will depend on several factors that can not currently be resolved but given magnitude of shear and instability the potential for widespread severe is evident. Showers and thunderstorms are expected to linger into Monday, with the end time depending on the speed of the upper trough which appears to be rather slow in its eastward progression. There are indications of lingering instability into the day on Monday in eastern KS but severe potential is questionable and quite low at this time. The upper low is showing a fair potential to slow and stall invof the western Great Lakes which would keep the local area in cool NW flow for several days with a fair amount of cloud cover. This long term forecast is rather uncertain though as even a minor eastward shift to the upper low would bring more frequent sunshine and temps would be quite a bit warmer. && .AVIATION...(For the 00Z TAFs through 00Z Friday Evening) Issued at 634 PM CDT THU MAY 8 2014 With the boundary apparently east of TOP and FOR, think the chances for convection in the terminals will continue to diminish this evening. So the forecast anticipates VFR conditions prevailing as northwest winds bring dryer air into the area. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Wolters SHORT TERM...Hennecke LONG TERM...Barjenbruch AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS TOPEKA KS
635 PM CDT Thu May 8 2014 .UPDATE... Issued at 634 PM CDT THU MAY 8 2014 Think the cold front will continue to make steady progress east, however outflow from recent convection seems to have masked the true front. The latest RAP and HRRR suggest the stronger convection could be east of the forecast area by 01Z and have trended the forecast in this direction. As the front makes clear progress east, will continue to clear out counties from the watch. Main hazard remains large hail, although available instability only around 1000 J/kg seems to be limiting the storms ability to maintain an updraft. Low level shear parameters do not look very supportive for much of a tornado threat. && .SHORT TERM...(Through Tonight) Issued at 252 PM CDT THU MAY 8 2014 The main focus for the short term is on the potential for thunderstorm development, with some strong to severe storms possible. Water vapor imagery showed the deep mid-level trough progressing eastward into the High Plains with a swath of dry air stretching across the western half of Kansas and the cloud cover gradually diminishing across eastern Kansas. The main surface low was situated over eastern Nebraska, with a secondary low developing over western Oklahoma near the Texas panhandle. As of 19z, the radar and surface obs showed the cold front stretching between these surface lows being located generally along a line from Seneca to Alma to Council Grove. Dewpoints ahead of this boundary where still in the low/mid 60s, with drier conditions settling in behind the boundary as dewpoints dropped into the upper 40s to upper 50s across north central Kansas. The cloud cover along with veering winds behind the front have limited afternoon heating with temperatures generally in the 70s. At 19z, radar showed a few showers and thunderstorms beginning to initiate along this boundary over far eastern/southeast Nebraska. Short-range models show this development continuing to spread southward along the boundary into northeast and eastern Kansas after 20z with more scattered storm development by the 22z-00z time frame, progressing eastward into Missouri during the evening hours. This region looks to be favorable for the development of strong to severe supercell thunderstorms as there is limited convective inhibition in place. MUCAPE is modest with upwards of 1000-2000 J/kg, and there is decent 0-6km bulk shear of 50-60kts. With the frontal passage, soundings show some veering of the low-level winds with 0-1km bulk shear potentially upwards of 15-20kts, so cannot rule out the potential for a few isolated tornadoes across far eastern Kansas. However, the main severe threat looks to be large hail with upwards of golfball size hail possible with the stronger storms. Could also see some damaging winds with this activity. These thunderstorms should initially be somewhat scattered in nature, and develop more into a line of storms by early this evening as the cold front progresses eastward, with this main thunderstorm activity diminishing by mid to late evening. However, additional shower and thunderstorm develop is possible overnight across east central Kansas as the secondary low tracks northeastward into southeast Kansas. Expect these storms to be elevated in nature and should exit east of the area Friday morning. Winds will continue to veer to the west and northwest behind the front tonight into Friday morning, with clearing skies across much of the northwestern half of the forecast area overnight. As a result, expect to see a spread in low temperatures tonight ranging from the middle 40s over north central Kansas to the middle 50s across east central Kansas due to the lingering shower and thunderstorm activity. .LONG TERM...(Friday through Thursday) Issued at 252 PM CDT THU MAY 8 2014 All indications are that the main PV anomaly/trough axis will exit the forecast area by around 15Z on Friday with a few lingering showers or even a thunderstorm possible through that time. Otherwise, expect downward motion and some dry advection to bring sunshine by afternoon. The post-frontal airmass is substantially cooler, but expect to mix up to 850 or even 800 hPa with sunshine and westerly winds, and still expect highs to climb into the 70s. Nearly zonal upper flow prevails into early Saturday with the front weakening and stalling over southern KS or northern OK. Should see dry conditions through Friday night and much of Saturday but expect the front to return north with warm moist advection Friday night into Saturday morning as surface low pressure develops from eastern Colorado into the OK panhandle. So have gone warmer with Friday night lows, and also a bit warmer on Saturday as cloud cover should be limited and the airmass rather warm. By Saturday afternoon, expect a negatively tilted short wave trough to eject across the Dakotas. This storm system will have a glancing impact on the local forecast area, but this bit of ascent will combine with moderate to strong instability expected by Saturday afternoon, along with a frontal boundary that will likely be lingering in the area or drifting back south across parts of Kansas. Expect the cap to be erased by mid to late afternoon, and the instability in conjunction with 30 to 50 kts of 0-6 km wind shear should result in scattered thunderstorms developing near the front. The most likely area seems to be near/south of I-70 at this time, and some of these storms would likely take on supercell characteristics with at least some potential for large hail. The wind potential will at least partially be tied to how warm temperatures get in the warm sector...warmer equating to greater damaging wind potential. Tornado potential seems on the low side given current forecast parameters given expectation for somewhat veered low level winds...but with a nearly stationary front in play, some small potential may exist. Expect a weak embedded short wave trough to perhaps enhance thunderstorm coverage near and even north of the front as the low level jet intensifies after sunset. This could allow the hail threat to persist north of the front through the overnight hours with elevated convection. On Sunday, expect a deep upper trough to begin to eject into the central Plains. The surface low is expected to deepen markedly over the OK panhandle while the surface front should remain across the local forecast area. One of the most significant uncertainties in the Sunday forecast regards the location of the front. The ECMWF is strongest/farthest north with the surface low and hence has the front extending across north central KS. The NAM...which can be flaky with details at the end of the forecast run...is stronger with the cold front progression and has the boundary along the boundary by 00Z Monday. The GFS is playing middle ground at this time. Another area of uncertainty lies in any stabilization that may occur with any overnight/early morning convection as we`ve seen with recent events. Wherever the boundary is located by Sunday afternoon, the warm sector south of the front should be characterized by strong to extreme instability and ample deep layer wind shear. Thunderstorms are likely to develop by mid afternoon along the front and become supercellular and severe. Low level winds again appear to be veered a bit but still with a fair amount of low level shear. All told, this appears to be an elevated chance for severe storms along and south of the frontal boundary...again focused near/south of I-70 for highest chances. The extent of storm severity will depend on several factors that can not currently be resolved but given magnitude of shear and instability the potential for widespread severe is evident. Showers and thunderstorms are expected to linger into Monday, with the end time depending on the speed of the upper trough which appears to be rather slow in its eastward progression. There are indications of lingering instability into the day on Monday in eastern KS but severe potential is questionable and quite low at this time. The upper low is showing a fair potential to slow and stall invof the western Great Lakes which would keep the local area in cool NW flow for several days with a fair amount of cloud cover. This long term forecast is rather uncertain though as even a minor eastward shift to the upper low would bring more frequent sunshine and temps would be quite a bit warmer. && .AVIATION...(For the 00Z TAFs through 00Z Friday Evening) Issued at 634 PM CDT THU MAY 8 2014 With the boundary apparently east of TOP and FOR, think the chances for convection in the terminals will continue to diminish this evening. So the forecast anticipates VFR conditions prevailing as northwest winds bring dryer air into the area. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...Wolters SHORT TERM...Hennecke LONG TERM...Barjenbruch AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
630 PM CDT Thu May 8 2014 ...Updated aviation section... .SHORT TERM...(This evening through Friday) ISSUED AT 329 PM CDT THU MAY 8 2014 Chances are greatest that most of the forecast area remains dry tonight. The front has shifted far enough east that the HRRR model solutions appear more believable than the NAM model`s solution of a retreating dryline returning moisture and allowing moist deep convection. The far west central Kansas counties such as Hamilton and Stanton could see showers and isolated thunderstorms early this evening associated with convective development over eastern Colorado. Of the various HiRes models, the NMM cores suggest a PV anomaly significant enough to produce showers on the backside of the upper jet, mainly late tonight and overnight. Instability will be minimal however and probabilities have been kept very low for the overnight episode. Temperatures overnight should fall into the low 50s and seen some 40s farther west where clearing is likely by 12 UTC. Weak westerly downslope surface winds will develop on Friday as surface high pressure spreads eastward across southeast Kansas during the afternoon. Other than mid level clouds, mostly sunny conditions should prevail based on model layer RH fields. The downslope flow will promote adiabatic warming resulting in boundary layer warm advection. Models are strongly aligned for highs in the mid to upper 70s with only bias corrected solutions creating warmer highs in the low 80s in the far southwest. .LONG TERM...(Friday night through Thursday) ISSUED AT 314 PM CDT THU MAY 8 2014 The medium range models continue to show a strong upper level shortwave digging into the western states this weekend and moving out into the plains by early next week. The ECMWF, GEM and UKMET models have all been similar and tend to be slower and deeper with this wave. The GFS has been more open and progressive with this wave for several runs. However, it is showing a tendency in its operational run...as well as some of the ensemble members...to be a little slower and deeper. Upper level westerly flow over the central High Plains on Friday will gradually become more southwesterly by Saturday night as the upper wave digs into the Intermountain West. As the upper wave approaches on Sunday, a frontal boundary should moves southward into western Kansas with a surface low pressure system developing along the front. There are some model differences in the position of this front during the day Sunday. The faster GFS has it through all of western Kansas by later in the afternoon while the other models keep it farther west. This will have significant impacts on daytime high temperatures as well as where the best chance for thunderstorms will be. Given the model tendencies, will keep the front farther west with a fairly significant temperature gradient across southwest and south central Kansas. The models show 60 degree dewpoints spreading northward into the central Plains ahead of this front. We could see an outbreak of severe storms along the front during the later afternoon and early evening hours as stronger southwesterly flow aloft moves into western Kansas. Chances for showers and thunderstorms will linger into Monday as the upper trough continues to move out into the Plains but we should be drying out by Monday night and Tuesday as the upper wave continues east. Temperatures in Monday-Wednesday time period will be fairly cool given the 850 millibar temperatures in the single digits. Temperatures should moderate through the remainder of the extended period as upper level heights build over the western and central U.S. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 629 PM CDT THU MAY 8 2014 VFR conditions will prevail with a few high clouds. Winds will generally be from the north around 10 knots. && .PRELIMINARY POINT TEMPS/POPS... DDC 45 77 48 82 / 20 0 0 0 GCK 43 78 47 81 / 20 0 0 0 EHA 44 79 50 85 / 20 0 0 0 LBL 45 80 48 86 / 10 0 0 0 HYS 43 78 48 80 / 10 10 0 0 P28 50 78 53 86 / 30 10 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Russell SHORT TERM...Russell LONG TERM...Gerard AVIATION...Hovorka_42
AREA FORECAST DISCUSSION
NWS TOPEKA KS
515 PM CDT Wed May 7 2014 ...AVIATION UPDATE... .SHORT TERM...(This Evening through Thursday) Issued at 304 PM CDT WED MAY 7 2014 Tonight through Thursday ... Water vapor imagery showed the deep mid-level trough stretched across the western U.S. with southwesterly flow aloft over the Central Plains. At the surface, low pressure stretched across southwest to north central Kansas with the dryline nearly bisecting the state from north to south at 20z. With a tight pressure gradient in place across much of the region, south-southwesterly winds were gusting upwards of 25-35mph this afternoon, which aided in decent WAA as well as moisture advection across eastern Kansas with dewpoints reaching into the lower to middle 60s. It was another mild day across the region as high temperatures rose into the upper 80s/low 90s across eastern Kansas and into the mid/upper 90s over north central Kansas. The warmest conditions across north central Kansas were co-located with the drier conditions as dewpoints plunged as low as into the middle 30s, resulting in RH values dropping into the teens. These dry conditions combined with the breezy winds will keep very high fire danger concerns in place through early this evening, so a Red Flag Warning remains in effect through 8pm across portions of north central Kansas. Visible satellite this afternoon showed a few storms popping up across northern Texas/southern Oklahoma along the dryline. The last few runs of the HRRR/RAP have shown good run-to-run consistency as well as good agreement with each other regarding the current mid-afternoon development and additional northward development of showers and thunderstorms along this dryline this evening. This initial thunderstorm development looks to be supported by a mid-level shortwave, and as this wave tracks northward into the area this evening it will help to provide enhanced lift over the region. Model soundings show the cap eroding away this afternoon across the central portions of the forecast area (roughly from Council Grove northward toward Manhattan), with short-range models showing this region being well-primed for scattered thunderstorm development, beginning between 22z-00z. MLCAPE values in this region could be upwards of 2000-3000 J/kg with upwards of 20-30kts of 0-6km bulk shear. As a result, the stronger storms may be capable of producing large hail and possibly some stronger wind gusts later this evening as the LLJ increases over the region. This activity should diminish overnight with the loss of diurnal heating. Southerly winds will remain breezy overnight due to the aforementioned increasing LLJ, so this strong southerly flow combined with increasing mid-level cloud cover will keep low temperatures tonight mild in the middle 60s west to upper 60s/near 70 east. There is the potential for strong to severe thunderstorms once again on Thursday as the mid-level trough ejects into the Central Plains, finally pushing the cold front associated with this system eastward across the area by Thursday night. 12z model runs have come into better agreement with the timing of this frontal passage and the eastward progression of the dryline through the day. Latest model trends show any morning precipitation to be focused across far eastern Kansas, but there are discrepancies with the coverage of this activity. Feel that this activity should be fairly limited, which would lead to more time for the environment to recover to support redevelopment of thunderstorms along the dryline during the afternoon hours. While there are still some minor discrepancies with the exact placement of the dryline by the afternoon, thunderstorm initiation looks to occur somewhere between Abilene and Manhattan and between 18z-21z. The cap looks to quickly weaken during the early/mid afternoon hours with upwards of 1500-2000 J/kg of MUCAPE and 45-55kts of 0-6km bulk shear. While there certainly looks to be decent shear in place, it looks to be fairly unidirectional. The main threats with the strongest storms will be large hail and damaging winds, but cannot rule out the potential for a few isolated tornadoes. The increasing mid-level cloud cover will limit the daytime heating with Thursday highs likely reaching into the middle 70s to low 80s. .LONG TERM...(Thursday Night through Wednesday) Issued at 304 PM CDT WED MAY 7 2014 Extended focus will be on impacts of first system Thursday night and second system over the weekend. Thurs Night...ongoing convection should become focused across east central Kansas as convergence is maximized along the north side of a secondary surface low and boundary so will keep high precip chcs across that area. Much cooler and drier air will arrive for Friday with highs back toward average in the lower 70s with dewpoints in the 40s. The next longwave trough will begin to take shape across the Rockies by Saturday with sfc low pressure forecast to develop across southeast Colorado. Moisture advection along and north of the developing warm front could result in SCT convection so will leave low pops on Sat. Better chances for showers and t-storms will arrive Saturday night into Sunday as the sfc low sags into western OK and the associated sfc front also sags south. It would appear that given moisture and shear that Sunday could bring a risk for severe storms but that is dependent on details of front position so confidence in severe risk Sunday is low at the moment. Overall confidence in weather trends is higher by Monday so look for a wet and colder start to the next work week with precip chcs decreasing Monday night and ending by Tuesday. Temps next week should remain near Average of 70 to 75. && .AVIATION...(For the 00Z TAFs through 00Z Thursday Evening) Issued at 515 PM CDT WED MAY 7 2014 Amended the TAFs to remove the TEMPO for TS at TOP and FOE. Latest RAP and NAM show the axis of instability remaining fairly close to the dryline with larger amounts of CIN to the east. Therefore confidence in TS moving into the terminals is to low to keep a tempo. MHK conversely is just east of the dryline with some convection bubbling up to the southwest. Therefore will keep the tempo, but have shortened the duration of the tempo based on the latest HRRR prog of convection. Also backed off on the MVFR CIGS for Thursday morning. Don`t see a huge increase in low level moisture so am not sure why the NAM is saturating the boundary layer. The RAP fails to saturate the boundary layer so am skeptical of a CIG and will just mention a SCT deck possible at TOP and FOE Thursday morning. && .TOP WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING until 8 PM CDT this evening FOR KSZ008-009-020- 021-034-035. && $$ SHORT TERM...Hennecke LONG TERM...Omitt AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS GOODLAND KS
147 PM MDT WED MAY 7 2014 .UPDATE... ISSUED AT 1048 AM MDT WED MAY 7 2014 ISSUED A WIND ADVISORY FOR THE SOUTHERNMOST SIX COUNTIES FOR LATER THIS AFTERNOON THROUGH EARLY EVENING. DEEP MIXING SHOULD ALLOW FOR GUSTS TO REACH 45 MPH IN THIS AREA. STILL SOME UNCERTAINTY HOW FAR NORTH STRONGER WINDS WILL DEVELOP BUT THE GREATEST THREAT OF ADVISORY CRITERIA WINDS SHOULD STAY SOUTH OF INTERSTATE 70. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM MDT WED MAY 7 2014 EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW DEEPENING TROUGH CURRENTLY CENTERED OVER THE GREAT BASIN WITH SW FLOW EXTENDING ACROSS CENTRAL ROCKIES AND PLAINS. AT THE SURFACE LOW PRESSURE CURRENTLY EXTENDS FROM EAST CENTRAL COLORADO ACROSS THE TRI STATE REGION WITH A STATIONARY FRONT BISECTING THIS FEATURE GENERALLY ALONG AND SOUTH OF INTERSTATE 70. A DRY LINE EXTENDING ACROSS CENTRAL KS HAS BEEN BACKING UP TOWARDS THE EASTERN PART OF OUR CWA. PARTICULARLY LOW CONFIDENCE IN FORECAST FOR TODAY AS A RESULT OF THE LINGERING STATIONARY FRONT AND INCONSISTENCIES BETWEEN GUIDANCE ON EVOLUTION OF SURFACE LOW AND FRONT TIMING AS UPPER TROUGH SHIFTS EAST INTO THE PLAINS. THIS IS A REFLECTION OF MODEL DIFFERENCES ON EVOLUTION/TRACK OF CLOSED H5/H7 LOW CENTERS ACROSS THE PLAINS TODAY/TONIGHT. WE COULD SEE WIDE RANGING IMPACTS DEPENDING ON ALL OF THE ABOVE MENTIONED VARIANCES ON BOTH OUR RFW...A POSSIBLE WIND ADVISORY...AND POTENTIAL SEVERE THUNDERSTORM DEVELOPMENT ACROSS THE NORTHERN HALF OF OUR CWA. THERE IS SO MUCH SPREAD BETWEEN MODELS FROM THE I-70 CORRIDOR NORTH ALL I WAS UNCOMFORTABLE DOING MORE THAN NUDGING TOWARDS THE LATEST BLENDS/NAM TRENDS. THIS PUTS THE SE HALF OF OUR CWA NEAR WIND ADVISORY CRITERIA...AND ANOTHER ROW OF COUNTIES WITHIN RFW CRITERIA. REGARDING THE CURRENT RFW AND POSSIBLE WIND ADVISORY...CONFIDENCE IS JUST TOO LOW TO MAKE HIGHLIGHT CHANGES. BASED ON EVOLUTION OF SURFACE FEATURES WE COULD SEE THUNDERSTORM INITIATION AND SEVERE POTENTIAL BY MIDDAY FURTHER SOUTH (I-70 CORRIDOR) BEFORE ANY PRIMARY THUNDERSTORM CHANCES TRANSITION NORTH AND WEST. WE WILL NEED TO MONITOR AND ADJUST AS CONFIDENCE INCREASE BASED ON REAL TIME DATA AND NEW RUNS OF SHORT RANGE GUIDANCE TO GET A BETTER HANDLE ON SENSIBLE WEATHER OVER OUR CWA THROUGH THIS EVENING. AS UPPER LOW TRANSITIONS EAST A COLD FRONT EVENTUALLY WILL PUSH SOUTH TONIGHT BEFORE STALLING ACROSS THE SOUTHERN PART OF OUR CWA. BESIDES COMPLICATING THE TEMP FORECAST...THIS FEATURE COULD ACT AS A FOCUS FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT AS A SECONDARY SHORTWAVE TROUGH MOVES ACROSS THE NORTHERN PLAINS BEHIND THE INITIAL UPPER LOW. I USED A CONSENSUS BLEND OF TEMPS THROUGH FRI AND LINGERED POPS THROUGH FRI NIGHT TO ACCOUNT FOR LIFT/MOISTURE ALONG FRONT AND ASSOCIATE WITH WEAK TROUGH PASSAGE. WHILE TEMPS SHOULD RETURN TO NEAR SEASONAL VALUES...IT DOES LOOK LIKE WE HAVE POTENTIAL FOR LOW TEMPS TO DROP WELL BELOW NORMAL IN THE 30S...AND ACTUALLY WITHIN FROST ADVISORY CRITERIA. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 135 PM MDT WED MAY 7 2014 TROUGH AXIS WILL BE MOVING EAST AND OUT OF THE AREA THURSDAY NIGHT WITH PRECIPITATION CHANCES DIMINISHING. CLEARING SKIES AND LIGHT WEST TO NORTHWEST WINDS WILL ALLOW TEMPERATURES TO DROP INTO THE UPPER 30S TO LOWER 40S...JUST ABOVE FROST ADVISORY CRITERIA. WEAK SHORTWAVE TROUGH EMBEDDED IN THE ZONAL FLOW ON FRIDAY AFTERNOON AND EVENING WILL BRING LOW CHANCES FOR RAIN SHOWERS IN NORTHEAST COLORADO AND THE NEBRASKA BORDER AREA...BUT WITH MUCAPE FORECAST TO BE ZERO DID NOT INCLUDE ANY MENTION OF THUNDER. TEMPERATURES WILL BE NEAR NORMAL...WITH LOWS FRIDAY NIGHT WELL ABOVE FROST CRITERIA. ZONAL FLOW ALOFT CONTINUES THROUGH THE REMAINDER OF THE EXTENDED PERIOD...WITH OCCASIONAL CHANCES FOR PRECIPITATION. BEST CHANCES APPEAR TO BE BETWEEN SATURDAY NIGHT AND MONDAY WITH A BETTER DEFINED SHORTWAVE TROUGH IN THE FLOW. THERE ARE SOME CONSIDERABLE TIMING DIFFERENCES AMONG THE MODELS SO DID NOT GET TOO SPECIFIC. THE COMBINATION OF CLOUDS AND COLD ADVECTION AT THE SURFACE WILL RESULT IN BELOW NORMAL TEMPERATURES. MUCAPE IS NEAR ZERO OR VERY LOW SO DO NOT HAVE ANY MENTION OF THUNDER UNTIL VERY LATE IN THE PERIOD WHEN MODELS HINT AT SOME WEAK INSTABILITY. WET BULB ZERO HEIGHTS SUGGEST A RAIN/SNOW MIX POSSIBLE SUNDAY AND MONDAY IN THE HIGHER TERRAIN OF THE WESTERN FORECAST AREA...BUT NO ACCUMULATION IS EXPECTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1142 AM MDT WED MAY 7 2014 VFR CONDITIONS ARE EXPECTED AT BOTH TERMINALS THROUGH THE PERIOD. THE WIND FORECAST IS QUITE CHALLENGING AND MAY REQUIRE AMENDMENTS THIS AFTERNOON. NORTHEASTERLY WINDS BEHIND A WEAK NEARLY STATIONARY FRONT HAVE PERSISTED THROUGH THE MORNING BUT SHOULD GRADUALLY TRANSITION TO SOUTHERLY AT GLD AS THE FRONT MOVES NORTHWARD. WINDS COULD BECOME GUSTY THIS AFTERNOON...ESPECIALLY AFTER 21Z LASTING INTO THE EARLY EVENING. AT KMCK WINDS ARE EXPECTED TO REMAIN EASTERLY/NORTHEASTERLY THROUGH THE FIRST PART OF THE NIGHT. AT BOTH TERMINALS A COLD FRONT WILL MOVE THROUGH LATE RESULTING IN A SHIFT TO NORTHWESTERLY WINDS...WITH GUSTS 30-35 KNOTS POSSIBLE...ESPECIALLY BY MID MORNING. THUNDERSTORMS WILL LIKELY FORM NORTH OF THE BOUNDARY LATE THIS AFTERNOON AND EVENING. THE GREATEST CHANCES WILL BE NORTHWEST OF BOTH TERMINALS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. WIND ADVISORY UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ027>029-041-042. CO...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ253-254. WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR COZ092. NE...NONE. && $$ UPDATE...BRB SHORT TERM...DR LONG TERM...024 AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1142 AM MDT WED MAY 7 2014 .UPDATE... ISSUED AT 1048 AM MDT WED MAY 7 2014 ISSUED A WIND ADVISORY FOR THE SOUTHERNMOST SIX COUNTIES FOR LATER THIS AFTERNOON THROUGH EARLY EVENING. DEEP MIXING SHOULD ALLOW FOR GUSTS TO REACH 45 MPH IN THIS AREA. STILL SOME UNCERTAINTY HOW FAR NORTH STRONGER WINDS WILL DEVELOP BUT THE GREATEST THREAT OF ADVISORY CRITERIA WINDS SHOULD STAY SOUTH OF INTERSTATE 70. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM MDT WED MAY 7 2014 EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW DEEPENING TROUGH CURRENTLY CENTERED OVER THE GREAT BASIN WITH SW FLOW EXTENDING ACROSS CENTRAL ROCKIES AND PLAINS. AT THE SURFACE LOW PRESSURE CURRENTLY EXTENDS FROM EASTCENTRAL COLORADO ACROSS THE TRI STATE REGION WITH A STATIONARY FRONT BISECTING THIS FEATURE GENERALLY ALONG AND SOUTH OF INTERSTATE 70. A DRY LINE EXTENDING ACROSS CENTRAL KS HAS BEEN BACKING UP TOWARDS THE EASTERN PART OF OUR CWA. PARTICULARLY LOW CONFIDENCE IN FORECAST FOR TODAY AS A RESULT OF THE LINGERING STATIONARY FRONT AND INCONSISTENCIES BETWEEN GUIDANCE ON EVOLUTION OF SURFACE LOW AND FRONT TIMING AS UPPER TROUGH SHIFTS EAST INTO THE PLAINS. THIS IS A REFLECTION OF MODEL DIFFERENCES ON EVOLUTION/TRACK OF CLOSED H5/H7 LOW CENTERS ACROSS THE PLAINS TODAY/TONIGHT. WE COULD SEE WIDE RANGING IMPACTS DEPENDING ON ALL OF THE ABOVE MENTIONED VARIANCES ON BOTH OUR RFW...A POSSIBLE WIND ADVISORY...AND POTENTIAL SEVERE THUNDERSTORM DEVELOPMENT ACROSS THE NORTHERN HALF OF OUR CWA. THERE IS SO MUCH SPREAD BETWEEN MODELS FROM THE I-70 CORRIDOR NORTH ALL I WAS UNCOMFORTABLE DOING MORE THAN NUDGING TOWARDS THE LATEST BLENDS/NAM TRENDS. THIS PUTS THE SE HALF OF OUR CWA NEAR WIND ADVISORY CRITERIA...AND ANOTHER ROW OF COUNTIES WITHIN RFW CRITERIA. REGARDING THE CURRENT RFW AND POSSIBLE WIND ADVISORY...CONFIDENCE IS JUST TOO LOW TO MAKE HIGHLIGHT CHANGES. BASED ON EVOLUTION OF SURFACE FEATURES WE COULD SEE THUNDERSTORM INITIATION AND SEVERE POTENTIAL BY MIDDAY FURTHER SOUTH (I-70 CORRIDOR) BEFORE ANY PRIMARY THUNDERSTORM CHANCES TRANSITION NORTH AND WEST. WE WILL NEED TO MONITOR AND ADJUST AS CONFIDENCE INCREASE BASED ON REAL TIME DATA AND NEW RUNS OF SHORT RANGE GUIDANCE TO GET A BETTER HANDLE ON SENSIBLE WEATHER OVER OUR CWA THROUGH THIS EVENING. AS UPPER LOW TRANSITIONS EAST A COLD FRONT EVENTUALLY WILL PUSH SOUTH TONIGHT BEFORE STALLING ACROSS THE SOUTHERN PART OF OUR CWA. BESIDES COMPLICATING THE TEMP FORECAST...THIS FEATURE COULD ACT AS A FOCUS FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT AS A SECONDARY SHORTWAVE TROUGH MOVES ACROSS THE NORTHERN PLAINS BEHIND THE INITIAL UPPER LOW. I USED A CONSENSUS BLEND OF TEMPS THROUGH FRI AND LINGERED POPS THROUGH FRI NIGHT TO ACCOUNT FOR LIFT/MOISTURE ALONG FRONT AND ASSOCIATE WITH WEAK TROUGH PASSAGE. WHILE TEMPS SHOULD RETURN TO NEAR SEASONAL VALUES...IT DOES LOOK LIKE WE HAVE POTENTIAL FOR LOW TEMPS TO DROP WELL BELOW NORMAL IN THE 30S...AND ACTUALLY WITHIN FROST ADVISORY CRITERIA. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 215 AM MDT WED MAY 7 2014 WESTERLY ZONAL FLOW ALOFT WILL BE PRESENT ACROSS THE HIGH PLAINS SATURDAY...WHICH WILL BRING BENIGN CONDITIONS ACROSS THE FORECAST AREA. A POSITIVELY TILTED UPPER LEVEL TROUGH WILL BEGIN TO MOVE INTO THE GREAT BASIN REGION AND CONTINUE TO PROGRESS INTO THE TRI STATE AREA SATURDAY NIGHT. MODEL RUNS DIFFER AS TO THE LOCATION OF THE ENSUING TROUGH AS WELL AS THE TIMING OF THE PASSAGE OF THE TROUGH AXIS THROUGH THE REGION...BUT THIS WEATHER MAKING SYSTEM SHOULD AFFECT THE AREA SOMETIME BETWEEN THE SATURDAY NIGHT TO MONDAY NIGHT TIME FRAME. MOST MODEL FORECASTS INDICATE A SHORTWAVE RIDGE WILL MOVE INTO THE HIGH PLAINS ONCE THE TROUGH AXIS MOVES EASTWARD ON TUESDAY...BUT THE GEM MODEL HAS THE UPPER LEVEL LOW SYSTEM BECOMING CUT OFF OVER THE HIGH PLAINS REGION. TENDED TO SIDE WITH THE DRY FORECAST AS THE ECMWF...GFS AND DGEX FORECASTS INDICATE THE RIDGE. THE MAIN CONCERN FOR THE LONG TERM FORECAST PERIOD WILL BE THE CHANCES FOR THUNDERSTORMS SATURDAY NIGHT THROUGH MONDAY. THUNDERSTORMS AND PRECIPITATION CHANCES MAY LINGER INTO TUESDAY IF THE FLOW ALOFT BECOMES CUT OFF...WHICH WILL AID IN MORE PRECIPITATION PRODUCTION. LATEST MODEL FORECASTS PLACE THE GREATEST MID AND LOWER LEVEL JET SPEEDS AND HIGHEST AREAS OF INSTABILITY WELL TO THE EAST OF THE FORECAST AREA FOR THE PERIOD FOR GREATEST PRECIPITATION POTENTIAL...SO THUNDERSTORM ACTIVITY IS NOT EXPECTED TO BECOME SEVERE. DUE TO THE ZONAL FLOW PATTERN SATURDAY FOLLOWED BY A PUSH OF COOLER AIR ALOFT WITH THE TROUGH PATTERN...TEMPERATURES THROUGH THE LONG TERM PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL WITH HIGHS GENERALLY IN THE MID 60S TO LOWER 70S. LOW TEMPERATURES WILL SPAN DURING THIS PERIOD BETWEEN THE LOW TO UPPER 40S...WITH SOME SPOTS IN EASTERN COLORADO DIPPING INTO THE UPPER 30S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1142 AM MDT WED MAY 7 2014 VFR CONDITIONS ARE EXPECTED AT BOTH TERMINALS THROUGH THE PERIOD. THE WIND FORECAST IS QUITE CHALLENGING AND MAY REQUIRE AMENDMENTS THIS AFTERNOON. NORTHEASTERLY WINDS BEHIND A WEAK NEARLY STATIONARY FRONT HAVE PERSISTED THROUGH THE MORNING BUT SHOULD GRADUALLY TRANSITION TO SOUTHERLY AT GLD AS THE FRONT MOVES NORTHWARD. WINDS COULD BECOME GUSTY THIS AFTERNOON...ESPECIALLY AFTER 21Z LASTING INTO THE EARLY EVENING. AT KMCK WINDS ARE EXPECTED TO REMAIN EASTERLY/NORTHEASTERLY THROUGH THE FIRST PART OF THE NIGHT. AT BOTH TERMINALS A COLD FRONT WILL MOVE THROUGH LATE RESULTING IN A SHIFT TO NORTHWESTERLY WINDS...WITH GUSTS 30-35 KNOTS POSSIBLE...ESPECIALLY BY MID MORNING. THUNDERSTORMS WILL LIKELY FORM NORTH OF THE BOUNDARY LATE THIS AFTERNOON AND EVENING. THE GREATEST CHANCES WILL BE NORTHWEST OF BOTH TERMINALS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. WIND ADVISORY FROM 3 PM MDT /4 PM CDT/ THIS AFTERNOON TO 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ027>029-041-042. CO...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ253-254. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM MDT THIS EVENING FOR COZ092. NE...NONE. && $$ UPDATE...BRB SHORT TERM...DR LONG TERM...MK AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1050 AM MDT WED MAY 7 2014 .UPDATE... ISSUED AT 1048 AM MDT WED MAY 7 2014 ISSUED A WIND ADVISORY FOR THE SOUTHERNMOST SIX COUNTIES FOR LATER THIS AFTERNOON THROUGH EARLY EVENING. DEEP MIXING SHOULD ALLOW FOR GUSTS TO REACH 45 MPH IN THIS AREA. STILL SOME UNCERTAINTY HOW FAR NORTH STRONGER WINDS WILL DEVELOP BUT THE GREATEST THREAT OF ADVISORY CRITERIA WINDS SHOULD STAY SOUTH OF INTERSTATE 70. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM MDT WED MAY 7 2014 EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW DEEPENING TROUGH CURRENTLY CENTERED OVER THE GREAT BASIN WITH SW FLOW EXTENDING ACROSS CENTRAL ROCKIES AND PLAINS. AT THE SURFACE LOW PRESSURE CURRENTLY EXTENDS FROM EASTCENTRAL COLORADO ACROSS THE TRI STATE REGION WITH A STATIONARY FRONT BISECTING THIS FEATURE GENERALLY ALONG AND SOUTH OF INTERSTATE 70. A DRY LINE EXTENDING ACROSS CENTRAL KS HAS BEEN BACKING UP TOWARDS THE EASTERN PART OF OUR CWA. PARTICULARLY LOW CONFIDENCE IN FORECAST FOR TODAY AS A RESULT OF THE LINGERING STATIONARY FRONT AND INCONSISTENCIES BETWEEN GUIDANCE ON EVOLUTION OF SURFACE LOW AND FRONT TIMING AS UPPER TROUGH SHIFTS EAST INTO THE PLAINS. THIS IS A REFLECTION OF MODEL DIFFERENCES ON EVOLUTION/TRACK OF CLOSED H5/H7 LOW CENTERS ACROSS THE PLAINS TODAY/TONIGHT. WE COULD SEE WIDE RANGING IMPACTS DEPENDING ON ALL OF THE ABOVE MENTIONED VARIANCES ON BOTH OUR RFW...A POSSIBLE WIND ADVISORY...AND POTENTIAL SEVERE THUNDERSTORM DEVELOPMENT ACROSS THE NORTHERN HALF OF OUR CWA. THERE IS SO MUCH SPREAD BETWEEN MODELS FROM THE I-70 CORRIDOR NORTH ALL I WAS UNCOMFORTABLE DOING MORE THAN NUDGING TOWARDS THE LATEST BLENDS/NAM TRENDS. THIS PUTS THE SE HALF OF OUR CWA NEAR WIND ADVISORY CRITERIA...AND ANOTHER ROW OF COUNTIES WITHIN RFW CRITERIA. REGARDING THE CURRENT RFW AND POSSIBLE WIND ADVISORY...CONFIDENCE IS JUST TOO LOW TO MAKE HIGHLIGHT CHANGES. BASED ON EVOLUTION OF SURFACE FEATURES WE COULD SEE THUNDERSTORM INITIATION AND SEVERE POTENTIAL BY MIDDAY FURTHER SOUTH (I-70 CORRIDOR) BEFORE ANY PRIMARY THUNDERSTORM CHANCES TRANSITION NORTH AND WEST. WE WILL NEED TO MONITOR AND ADJUST AS CONFIDENCE INCREASE BASED ON REAL TIME DATA AND NEW RUNS OF SHORT RANGE GUIDANCE TO GET A BETTER HANDLE ON SENSIBLE WEATHER OVER OUR CWA THROUGH THIS EVENING. AS UPPER LOW TRANSITIONS EAST A COLD FRONT EVENTUALLY WILL PUSH SOUTH TONIGHT BEFORE STALLING ACROSS THE SOUTHERN PART OF OUR CWA. BESIDES COMPLICATING THE TEMP FORECAST...THIS FEATURE COULD ACT AS A FOCUS FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT AS A SECONDARY SHORTWAVE TROUGH MOVES ACROSS THE NORTHERN PLAINS BEHIND THE INITIAL UPPER LOW. I USED A CONSENSUS BLEND OF TEMPS THROUGH FRI AND LINGERED POPS THROUGH FRI NIGHT TO ACCOUNT FOR LIFT/MOISTURE ALONG FRONT AND ASSOCIATE WITH WEAK TROUGH PASSAGE. WHILE TEMPS SHOULD RETURN TO NEAR SEASONAL VALUES...IT DOES LOOK LIKE WE HAVE POTENTIAL FOR LOW TEMPS TO DROP WELL BELOW NORMAL IN THE 30S...AND ACTUALLY WITHIN FROST ADVISORY CRITERIA. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 215 AM MDT WED MAY 7 2014 WESTERLY ZONAL FLOW ALOFT WILL BE PRESENT ACROSS THE HIGH PLAINS SATURDAY...WHICH WILL BRING BENIGN CONDITIONS ACROSS THE FORECAST AREA. A POSITIVELY TILTED UPPER LEVEL TROUGH WILL BEGIN TO MOVE INTO THE GREAT BASIN REGION AND CONTINUE TO PROGRESS INTO THE TRI STATE AREA SATURDAY NIGHT. MODEL RUNS DIFFER AS TO THE LOCATION OF THE ENSUING TROUGH AS WELL AS THE TIMING OF THE PASSAGE OF THE TROUGH AXIS THROUGH THE REGION...BUT THIS WEATHER MAKING SYSTEM SHOULD AFFECT THE AREA SOMETIME BETWEEN THE SATURDAY NIGHT TO MONDAY NIGHT TIME FRAME. MOST MODEL FORECASTS INDICATE A SHORTWAVE RIDGE WILL MOVE INTO THE HIGH PLAINS ONCE THE TROUGH AXIS MOVES EASTWARD ON TUESDAY...BUT THE GEM MODEL HAS THE UPPER LEVEL LOW SYSTEM BECOMING CUT OFF OVER THE HIGH PLAINS REGION. TENDED TO SIDE WITH THE DRY FORECAST AS THE ECMWF...GFS AND DGEX FORECASTS INDICATE THE RIDGE. THE MAIN CONCERN FOR THE LONG TERM FORECAST PERIOD WILL BE THE CHANCES FOR THUNDERSTORMS SATURDAY NIGHT THROUGH MONDAY. THUNDERSTORMS AND PRECIPITATION CHANCES MAY LINGER INTO TUESDAY IF THE FLOW ALOFT BECOMES CUT OFF...WHICH WILL AID IN MORE PRECIPITATION PRODUCTION. LATEST MODEL FORECASTS PLACE THE GREATEST MID AND LOWER LEVEL JET SPEEDS AND HIGHEST AREAS OF INSTABILITY WELL TO THE EAST OF THE FORECAST AREA FOR THE PERIOD FOR GREATEST PRECIPITATION POTENTIAL...SO THUNDERSTORM ACTIVITY IS NOT EXPECTED TO BECOME SEVERE. DUE TO THE ZONAL FLOW PATTERN SATURDAY FOLLOWED BY A PUSH OF COOLER AIR ALOFT WITH THE TROUGH PATTERN...TEMPERATURES THROUGH THE LONG TERM PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL WITH HIGHS GENERALLY IN THE MID 60S TO LOWER 70S. LOW TEMPERATURES WILL SPAN DURING THIS PERIOD BETWEEN THE LOW TO UPPER 40S...WITH SOME SPOTS IN EASTERN COLORADO DIPPING INTO THE UPPER 30S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 545 AM MDT WED MAY 7 2014 EARLY IN THE TAF PERIODS LOW LEVEL MOISTURE POOLING NORTH OF STATIONARY FRONT WILL LEAD TO VIS VARYING FROM 4-7SM OVER NW KS AND SW NE THROUGH ABOUT 15Z. NOT CONFIDENT ENOUGH TO PUT MVFR VIS IN TAF...SO LIMITED VIS RESTRICTION TO 6SM AS THIS LIGHT FOG IS FAIRLY PATCHY. AS FRONT LIFTS NORTH TODAY AND SURFACE LOW DEEPENS GUSTY SOUTH WINDS WILL DEVELOP WITH GUSTS TO 30KT AT KGLD AND AROUND 20-25KT AT MCK. A LOT OF SPREAD ON GUIDANCE ON TIMING OF THIS FRONT AND A POTENTIAL COLD FRONT TONIGHT. FOR NOW SHOWED WIND SHIFT TO W-NW TONIGHT AT BOTH TERMINALS BASED ON LATEST NAM/RAP. WITH SLOWER WARM FRONT IT LOOKS LIKE A FEW THUNDERSTORMS COULD DEVELOP AROUND BOTH TERMINALS...HOWEVER AT THIS TIME CONFIDENCE WAS TOO LOW IN INITIATION OR COVERAGE TO ADD MENTION TO TAFS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. WIND ADVISORY FROM 3 PM MDT /4 PM CDT/ THIS AFTERNOON TO 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ027>029-041-042. CO...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ253-254. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM MDT THIS EVENING FOR COZ092. NE...NONE. && $$ UPDATE...BRB SHORT TERM...DR LONG TERM...MK AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
545 AM MDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM MDT WED MAY 7 2014 EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW DEEPENING TROUGH CURRENTLY CENTERED OVER THE GREAT BASIN WITH SW FLOW EXTENDING ACROSS CENTRAL ROCKIES AND PLAINS. AT THE SURFACE LOW PRESSURE CURRENTLY EXTENDS FROM EASTCENTRAL COLORADO ACROSS THE TRI STATE REGION WITH A STATIONARY FRONT BISECTING THIS FEATURE GENERALLY ALONG AND SOUTH OF INTERSTATE 70. A DRY LINE EXTENDING ACROSS CENTRAL KS HAS BEEN BACKING UP TOWARDS THE EASTERN PART OF OUR CWA. PARTICULARLY LOW CONFIDENCE IN FORECAST FOR TODAY AS A RESULT OF THE LINGERING STATIONARY FRONT AND INCONSISTENCIES BETWEEN GUIDANCE ON EVOLUTION OF SURFACE LOW AND FRONT TIMING AS UPPER TROUGH SHIFTS EAST INTO THE PLAINS. THIS IS A REFLECTION OF MODEL DIFFERENCES ON EVOLUTION/TRACK OF CLOSED H5/H7 LOW CENTERS ACROSS THE PLAINS TODAY/TONIGHT. WE COULD SEE WIDE RANGING IMPACTS DEPENDING ON ALL OF THE ABOVE MENTIONED VARIANCES ON BOTH OUR RFW...A POSSIBLE WIND ADVISORY...AND POTENTIAL SEVERE THUNDERSTORM DEVELOPMENT ACROSS THE NORTHERN HALF OF OUR CWA. THERE IS SO MUCH SPREAD BETWEEN MODELS FROM THE I-70 CORRIDOR NORTH ALL I WAS UNCOMFORTABLE DOING MORE THAN NUDGING TOWARDS THE LATEST BLENDS/NAM TRENDS. THIS PUTS THE SE HALF OF OUR CWA NEAR WIND ADVISORY CRITERIA...AND ANOTHER ROW OF COUNTIES WITHIN RFW CRITERIA. REGARDING THE CURRENT RFW AND POSSIBLE WIND ADVISORY...CONFIDENCE IS JUST TOO LOW TO MAKE HIGHLIGHT CHANGES. BASED ON EVOLUTION OF SURFACE FEATURES WE COULD SEE THUNDERSTORM INITIATION AND SEVERE POTENTIAL BY MIDDAY FURTHER SOUTH (I-70 CORRIDOR) BEFORE ANY PRIMARY THUNDERSTORM CHANCES TRANSITION NORTH AND WEST. WE WILL NEED TO MONITOR AND ADJUST AS CONFIDENCE INCREASE BASED ON REAL TIME DATA AND NEW RUNS OF SHORT RANGE GUIDANCE TO GET A BETTER HANDLE ON SENSIBLE WEATHER OVER OUR CWA THROUGH THIS EVENING. AS UPPER LOW TRANSITIONS EAST A COLD FRONT EVENTUALLY WILL PUSH SOUTH TONIGHT BEFORE STALLING ACROSS THE SOUTHERN PART OF OUR CWA. BESIDES COMPLICATING THE TEMP FORECAST...THIS FEATURE COULD ACT AS A FOCUS FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT AS A SECONDARY SHORTWAVE TROUGH MOVES ACROSS THE NORTHERN PLAINS BEHIND THE INITIAL UPPER LOW. I USED A CONSENSUS BLEND OF TEMPS THROUGH FRI AND LINGERED POPS THROUGH FRI NIGHT TO ACCOUNT FOR LIFT/MOISTURE ALONG FRONT AND ASSOCIATE WITH WEAK TROUGH PASSAGE. WHILE TEMPS SHOULD RETURN TO NEAR SEASONAL VALUES...IT DOES LOOK LIKE WE HAVE POTENTIAL FOR LOW TEMPS TO DROP WELL BELOW NORMAL IN THE 30S...AND ACTUALLY WITHIN FROST ADVISORY CRITERIA. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 215 AM MDT WED MAY 7 2014 WESTERLY ZONAL FLOW ALOFT WILL BE PRESENT ACROSS THE HIGH PLAINS SATURDAY...WHICH WILL BRING BENIGN CONDITIONS ACROSS THE FORECAST AREA. A POSITIVELY TILTED UPPER LEVEL TROUGH WILL BEGIN TO MOVE INTO THE GREAT BASIN REGION AND CONTINUE TO PROGRESS INTO THE TRI STATE AREA SATURDAY NIGHT. MODEL RUNS DIFFER AS TO THE LOCATION OF THE ENSUING TROUGH AS WELL AS THE TIMING OF THE PASSAGE OF THE TROUGH AXIS THROUGH THE REGION...BUT THIS WEATHER MAKING SYSTEM SHOULD AFFECT THE AREA SOMETIME BETWEEN THE SATURDAY NIGHT TO MONDAY NIGHT TIME FRAME. MOST MODEL FORECASTS INDICATE A SHORTWAVE RIDGE WILL MOVE INTO THE HIGH PLAINS ONCE THE TROUGH AXIS MOVES EASTWARD ON TUESDAY...BUT THE GEM MODEL HAS THE UPPER LEVEL LOW SYSTEM BECOMING CUT OFF OVER THE HIGH PLAINS REGION. TENDED TO SIDE WITH THE DRY FORECAST AS THE ECMWF...GFS AND DGEX FORECASTS INDICATE THE RIDGE. THE MAIN CONCERN FOR THE LONG TERM FORECAST PERIOD WILL BE THE CHANCES FOR THUNDERSTORMS SATURDAY NIGHT THROUGH MONDAY. THUNDERSTORMS AND PRECIPITATION CHANCES MAY LINGER INTO TUESDAY IF THE FLOW ALOFT BECOMES CUT OFF...WHICH WILL AID IN MORE PRECIPITATION PRODUCTION. LATEST MODEL FORECASTS PLACE THE GREATEST MID AND LOWER LEVEL JET SPEEDS AND HIGHEST AREAS OF INSTABILITY WELL TO THE EAST OF THE FORECAST AREA FOR THE PERIOD FOR GREATEST PRECIPITATION POTENTIAL...SO THUNDERSTORM ACTIVITY IS NOT EXPECTED TO BECOME SEVERE. DUE TO THE ZONAL FLOW PATTERN SATURDAY FOLLOWED BY A PUSH OF COOLER AIR ALOFT WITH THE TROUGH PATTERN...TEMPERATURES THROUGH THE LONG TERM PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL WITH HIGHS GENERALLY IN THE MID 60S TO LOWER 70S. LOW TEMPERATURES WILL SPAN DURING THIS PERIOD BETWEEN THE LOW TO UPPER 40S...WITH SOME SPOTS IN EASTERN COLORADO DIPPING INTO THE UPPER 30S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 545 AM MDT WED MAY 7 2014 EARLY IN THE TAF PERIODS LOW LEVEL MOISTURE POOLING NORTH OF STATIONARY FRONT WILL LEAD TO VIS VARYING FROM 4-7SM OVER NW KS AND SW NE THROUGH ABOUT 15Z. NOT CONFIDENT ENOUGH TO PUT MVFR VIS IN TAF...SO LIMITED VIS RESTRICTION TO 6SM AS THIS LIGHT FOG IS FAIRLY PATCHY. AS FRONT LIFTS NORTH TODAY AND SURFACE LOW DEEPENS GUSTY SOUTH WINDS WILL DEVELOP WITH GUSTS TO 30KT AT KGLD AND AROUND 20-25KT AT MCK. A LOT OF SPREAD ON GUIDANCE ON TIMING OF THIS FRONT AND A POTENTIAL COLD FRONT TONIGHT. FOR NOW SHOWED WIND SHIFT TO W-NW TONIGHT AT BOTH TERMINALS BASED ON LATEST NAM/RAP. WITH SLOWER WARM FRONT IT LOOKS LIKE A FEW THUNDERSTORMS COULD DEVELOP AROUND BOTH TERMINALS...HOWEVER AT THIS TIME CONFIDENCE WAS TOO LOW IN INITIATION OR COVERAGE TO ADD MENTION TO TAFS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING FROM 11 AM MDT /NOON CDT/ THIS MORNING TO 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. CO...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM MDT THIS EVENING FOR COZ253-254. NE...NONE. && $$ SHORT TERM...DR LONG TERM...MK AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 AM MDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM MDT WED MAY 7 2014 EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW DEEPENING TROUGH CURRENTLY CENTERED OVER THE GREAT BASIN WITH SW FLOW EXTENDING ACROSS CENTRAL ROCKIES AND PLAINS. AT THE SURFACE LOW PRESSURE CURRENTLY EXTENDS FROM EASTCENTRAL COLORADO ACROSS THE TRI STATE REGION WITH A STATIONARY FRONT BISECTING THIS FEATURE GENERALLY ALONG AND SOUTH OF INTERSTATE 70. A DRY LINE EXTENDING ACROSS CENTRAL KS HAS BEEN BACKING UP TOWARDS THE EASTERN PART OF OUR CWA. PARTICULARLY LOW CONFIDENCE IN FORECAST FOR TODAY AS A RESULT OF THE LINGERING STATIONARY FRONT AND INCONSISTENCIES BETWEEN GUIDANCE ON EVOLUTION OF SURFACE LOW AND FRONT TIMING AS UPPER TROUGH SHIFTS EAST INTO THE PLAINS. THIS IS A REFLECTION OF MODEL DIFFERENCES ON EVOLUTION/TRACK OF CLOSED H5/H7 LOW CENTERS ACROSS THE PLAINS TODAY/TONIGHT. WE COULD SEE WIDE RANGING IMPACTS DEPENDING ON ALL OF THE ABOVE MENTIONED VARIANCES ON BOTH OUR RFW...A POSSIBLE WIND ADVISORY...AND POTENTIAL SEVERE THUNDERSTORM DEVELOPMENT ACROSS THE NORTHERN HALF OF OUR CWA. THERE IS SO MUCH SPREAD BETWEEN MODELS FROM THE I-70 CORRIDOR NORTH ALL I WAS UNCOMFORTABLE DOING MORE THAN NUDGING TOWARDS THE LATEST BLENDS/NAM TRENDS. THIS PUTS THE SE HALF OF OUR CWA NEAR WIND ADVISORY CRITERIA...AND ANOTHER ROW OF COUNTIES WITHIN RFW CRITERIA. REGARDING THE CURRENT RFW AND POSSIBLE WIND ADVISORY...CONFIDENCE IS JUST TOO LOW TO MAKE HIGHLIGHT CHANGES. BASED ON EVOLUTION OF SURFACE FEATURES WE COULD SEE THUNDERSTORM INITIATION AND SEVERE POTENTIAL BY MIDDAY FURTHER SOUTH (I-70 CORRIDOR) BEFORE ANY PRIMARY THUNDERSTORM CHANCES TRANSITION NORTH AND WEST. WE WILL NEED TO MONITOR AND ADJUST AS CONFIDENCE INCREASE BASED ON REAL TIME DATA AND NEW RUNS OF SHORT RANGE GUIDANCE TO GET A BETTER HANDLE ON SENSIBLE WEATHER OVER OUR CWA THROUGH THIS EVENING. AS UPPER LOW TRANSITIONS EAST A COLD FRONT EVENTUALLY WILL PUSH SOUTH TONIGHT BEFORE STALLING ACROSS THE SOUTHERN PART OF OUR CWA. BESIDES COMPLICATING THE TEMP FORECAST...THIS FEATURE COULD ACT AS A FOCUS FOR ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT AS A SECONDARY SHORTWAVE TROUGH MOVES ACROSS THE NORTHERN PLAINS BEHIND THE INITIAL UPPER LOW. I USED A CONSENSUS BLEND OF TEMPS THROUGH FRI AND LINGERED POPS THROUGH FRI NIGHT TO ACCOUNT FOR LIFT/MOISTURE ALONG FRONT AND ASSOCIATE WITH WEAK TROUGH PASSAGE. WHILE TEMPS SHOULD RETURN TO NEAR SEASONAL VALUES...IT DOES LOOK LIKE WE HAVE POTENTIAL FOR LOW TEMPS TO DROP WELL BELOW NORMAL IN THE 30S...AND ACTUALLY WITHIN FROST ADVISORY CRITERIA. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 215 AM MDT WED MAY 7 2014 WESTERLY ZONAL FLOW ALOFT WILL BE PRESENT ACROSS THE HIGH PLAINS SATURDAY...WHICH WILL BRING BENIGN CONDITIONS ACROSS THE FORECAST AREA. A POSITIVELY TILTED UPPER LEVEL TROUGH WILL BEGIN TO MOVE INTO THE GREAT BASIN REGION AND CONTINUE TO PROGRESS INTO THE TRI STATE AREA SATURDAY NIGHT. MODEL RUNS DIFFER AS TO THE LOCATION OF THE ENSUING TROUGH AS WELL AS THE TIMING OF THE PASSAGE OF THE TROUGH AXIS THROUGH THE REGION...BUT THIS WEATHER MAKING SYSTEM SHOULD AFFECT THE AREA SOMETIME BETWEEN THE SATURDAY NIGHT TO MONDAY NIGHT TIME FRAME. MOST MODEL FORECASTS INDICATE A SHORTWAVE RIDGE WILL MOVE INTO THE HIGH PLAINS ONCE THE TROUGH AXIS MOVES EASTWARD ON TUESDAY...BUT THE GEM MODEL HAS THE UPPER LEVEL LOW SYSTEM BECOMING CUT OFF OVER THE HIGH PLAINS REGION. TENDED TO SIDE WITH THE DRY FORECAST AS THE ECMWF...GFS AND DGEX FORECASTS INDICATE THE RIDGE. THE MAIN CONCERN FOR THE LONG TERM FORECAST PERIOD WILL BE THE CHANCES FOR THUNDERSTORMS SATURDAY NIGHT THROUGH MONDAY. THUNDERSTORMS AND PRECIPITATION CHANCES MAY LINGER INTO TUESDAY IF THE FLOW ALOFT BECOMES CUT OFF...WHICH WILL AID IN MORE PRECIPITATION PRODUCTION. LATEST MODEL FORECASTS PLACE THE GREATEST MID AND LOWER LEVEL JET SPEEDS AND HIGHEST AREAS OF INSTABILITY WELL TO THE EAST OF THE FORECAST AREA FOR THE PERIOD FOR GREATEST PRECIPITATION POTENTIAL...SO THUNDERSTORM ACTIVITY IS NOT EXPECTED TO BECOME SEVERE. DUE TO THE ZONAL FLOW PATTERN SATURDAY FOLLOWED BY A PUSH OF COOLER AIR ALOFT WITH THE TROUGH PATTERN...TEMPERATURES THROUGH THE LONG TERM PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL WITH HIGHS GENERALLY IN THE MID 60S TO LOWER 70S. LOW TEMPERATURES WILL SPAN DURING THIS PERIOD BETWEEN THE LOW TO UPPER 40S...WITH SOME SPOTS IN EASTERN COLORADO DIPPING INTO THE UPPER 30S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1140 PM MDT TUE MAY 6 2014 VFR CONDITIONS WILL PREVAIL AT MCK AND GLD THROUGH THE TAF PERIOD. A WARM FRONT PUSHES NORTH ACROSS THE REGION DURING THE DAY ON WEDNESDAY AS A SURFACE LOW PRESSURE CENTER DEEPENS OVER EASTERN COLORADO. AS THE FRONT PASSES OVER THE TAF SITES BETWEEN 19-21Z...WINDS ARE EXPECTED TO TURN SOUTH AND BECOME GUSTY DURING THE AFTERNOON AND EVENING. THERE IS A POSSIBILITY OF PATCHY FOG DEVELOPING NEAR MCK BETWEEN 10Z-14Z WEDNESDAY MORNING AS TEMPERATURES COOL AND APPROACH THE DEWPOINT VALUES IN THE LOWER 50S WHICH WILL BRING THE BOUNDARY LAYER NEAR SATURATION. HAVE INCLUDED A PREVAILING CONDITION OF 6SM WITH A LOW CLOUD LAYER AT MCK AS A RESULT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING FROM 11 AM MDT /NOON CDT/ THIS MORNING TO 9 PM MDT /10 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. CO...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM MDT THIS EVENING FOR COZ253-254. NE...NONE. && $$ SHORT TERM...DR LONG TERM...MK AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS PADUCAH KY
845 PM CDT Thu May 8 2014 .UPDATE... Issued at 845 PM CDT THU MAY 8 2014 A north to south oriented line of thunderstorms with trailing stratiform rain is approaching the Mississippi River and will continue to move north northeast into southern Illinois mainly to the west of I-57 through the remainder of the evening. It looks like western portions of southeast Missouri will be drying out pretty soon, and they may have a few hours before the next round arrives midnight or a bit later. LAPS soundings indicate a weakening cap and the RAP has LI`s of -2 to -3 over southern Illinois. See no reason why they will not continue through much of southern Illinois with modest intensity this evening. Not sure just how far east they will get, but the RAP tries hard to confine the precipitation to Missouri and Illinois through midnight. Of course, as the upper trough pushes closer to the area overnight, another round of widespread showers and thunderstorms is expected to overspread most of the area by daybreak Friday morning. Tried to account for the aforementioned trends in the hourly pop/wx grids, but made few other changes with this update. The Lake Wind Advisory died a natural death at 01Z. UPDATE Issued at 610 PM CDT THU MAY 8 2014 UPDATE FOR AVIATION ONLY. && .SHORT TERM...(Tonight through Saturday night) Issued at 304 PM CDT THU MAY 8 2014 Focus in the short term continues to be on convective chances. Band of convection central/sw MO into west AR will track slowly east late this afternoon and evening. Will have best chance PoPs west 1/2 before midnight shifting slowly east overnight. Really not all that concerned about severe wx over our SEMO counties at this time given marginal lapse rates modest instability. Convective chances will shift east Friday morning. It may linger from SW IN into the Pennyrile through early afternoon, where temps may be held down a couple of degrees. Otherwise, the atmosphere should have some time to recover heading west, ahead of an approaching, stalling front. Convection should take shape in this area and eventually focus SRN IL into SE MO late in the day in some form or fashion then head east through the evening. Mid and upper level winds are relatively impressive, not so much blyr- 700mb. Storms with decent mid level rotation, with steepening low level lapse rates may yield wind and hailers, best chances west/southwest part of the CWFA. Chances should diminish from west to east after midnight Friday night. May see a lull Saturday, then another chance moving in from the west overnight Saturday night, potentially an MCS. Slightly better chances north than south. .LONG TERM...(Sunday through Thursday) Issued at 304 PM CDT THU MAY 8 2014 The main weather story during the long term will be a strong cold front that will sweep across our region early next week. This front will be accompanied by a period of rain and thunderstorms. The front will bring a noticeable cooling of temperatures from above normal to below normal. As far as the daily details... On Sunday...a reservoir of warm...moist and very unstable air will cover a large part of the central states including our region. It is likely that one or more convective systems will develop over the Plains and then propagate eastward through this unstable air mass...fed by a moderately strong low level jet. Since there is little skill at forecasting these systems in the long range period...the forecast will include a generic chance pop. High temps will remain quite warm...basically in line with gfs/ecmwf mos. On Monday...the high amplitude 500 mb trough and associated cold front will draw closer. The genesis region of convective systems will remain to our west. Will continue with a warm and humid forecast along with chance pops. There remains unusually wide divergence among the models concerning the timing of the frontal system Monday night through Tuesday night. Both the gfs and ecmwf have trended slower compared to this time Wednesday. The 12z gfs takes the front across our region on Monday night...while the ecmwf has it coming through Tuesday night. The highest pops will be on Tuesday...mainly in the likely category across our region. Will introduce chance pops for Wednesday based on the slower timing of the system. However...the bulk of the precip should be over by then. The model 850 temps have trended cooler for Wednesday into Thursday by several degrees. Based on model 850 mb temps from plus 1 to plus 4...highs will only be in the 60s even with plenty of sun. Forecast temps will be trended lower for Wed into Thurs. && .AVIATION... Issued at 610 PM CDT THU MAY 8 2014 Showers were developing over SEMO and heading straight for KCGI. Amended old taf and included mention in new set. These echoes were intensifying and could lay down a strike or two. This convection is expected to dissipate with the loss of daytime heating with the main area moving into the taf sites between 5z and 8z. Also introduced WS overnight as fcst sounding indicate a 40kt SSW flow around 2k feet. Expect mostly MVFR cigs and vsby through most of the valid time of the tafs after the precip moves in. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS AVIATION...KH
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
955 PM CDT THU MAY 8 2014 .DISCUSSION... REGIONAL 88DS SHOW A LINE OF THUNDERSTORMS STRETCHING FROM THE ARKLATEX THROUGH NERN TX TO NOT QUITE THE HILL COUNTRY. SRN END OF THE LINE HAS BEEN SLOW TO DEVELOP THIS EVENING AS BEST DYNAMICS PUSH NEWD WITH THE ATTENDANT DISTURBANCE ALOFT. THIS SCENARIO GOES WELL WITH BOTH THE LATEST GFS AND HRRR RUNS WHICH KEEP THE BULK OF THE PRECIP ACROSS NRN LA. THUS HAVE LOWERED POPS BACK TO JUST THE CHANCE CATEGORY FOR THE REST OF THE NIGHT TO ACCOUNT. BIG QUESTION APPEARS TO BE RAIN CHANCES OVER THE SERN ZONES AS RADARS ARE BEGINNING TO LIGHT UP OVER THE NWRN GULF AS ACTIVITY INCREASES WITH NEXT DISTURBANCE ROUNDING THE BASE OF THE TROF...AND THUS HAVE NUDGED UP POPS SLIGHTLY OVER THIS AREA TO ACCOUNT. ELSEWHERE JUST MINOR TWEAKS MADE TO INHERITED GRIDS/ZONES. UPDATE OUT SHORTLY. 25 && .PREV DISCUSSION... /ISSUED 618 PM CDT THU MAY 8 2014/ AVIATION... AREAS OF RAIN AND SHOWERS MIXED WILL CONT THRU THE EVENING HOURS. STORMS ARE MOVING OUT OF THE DFW AREA AND INTO CNTRL TX ATTM. CEILINGS VARYING FROM VFR TO IFR DEPENDING ON STORM LOCATION TO THE TAF SITES. THIS TYPE OF PATTERN WILL CONTINUE INTO THE OVERNIGHT HOURS. PREV DISCUSSION... /ISSUED 354 PM CDT THU MAY 8 2014/ DISCUSSION...CONDITIONS ARE MOISTENING ACROSS THE REGION THIS AFTERNOON WITH LIGHT RAIN COVERING MOST OF SE TX AND PUSHING INTO FAR WEST LA AS AN UPPER DISTURBANCE APPROACHES FROM THE WEST. LIGHT RAIN WITH A FEW EMBEDDED HEAVIER SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THROUGH THE EVENING. LIFT AND MOISTURE WILL CONTINUE TO INCREASE TONIGHT WITH SHOWERS AND STORMS REMAINING LIKELY FOR THE NORTHERN ZONES AND SCT FOR THE SOUTHERN PORTIONS. WITH THE AREA RECEIVING HIGH MOISTURE CONTENT AND MODEST UPPER SUPPORT BUT LACKING ANY SURFACE BOUNDARY OR FOCUS, RAIN AND STORMS WILL REMAIN SCT TO NUMEROUS, AND GENERALLY LESS THAN WIDESPREAD TONIGHT INTO FRIDAY. THE BEST SUPPORT FOR RAIN WILL MOVE EAST OF THE AREA FRIDAY INTO SATURDAY WITH SUNDAY KEEPING ONLY A SLIGHT CHANCE AROUND. RAIN CHANCES WILL INCREASE AGAIN MONDAY INTO TUESDAY AS A COLD FRONT MOVES INTO AND THEN THROUGH THE REGION. DRIER AND SLIGHTLY COOLER WEATHER WILL RETURN TO THE REGION BY THE MIDDLE OF THE COMING WEEK. MARINE...THE WINDS WILL DECREASE THROUGH THE EVENING AS THE PRESSURE GRADIENT RELAXES ACROSS THE AREA. WINDS WILL REMAIN GENERALLY SOUTH TO SOUTHEAST INTO EARLY NEXT WEEK. A COLD FRONT MAY MOVE OFF THE COAST DURING TUESDAY VEERING THE WINDS OFFSHORE. && .PRELIMINARY POINT TEMPS/POPS... KLCH 72 83 70 85 71 / 30 50 30 20 10 KBPT 72 84 70 84 71 / 30 30 30 20 10 KAEX 71 85 67 87 68 / 30 60 30 20 10 KLFT 72 83 71 84 71 / 30 70 40 40 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT EXERCISE CAUTION UNTIL 1 AM CDT FRIDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA OUT 20 NM...COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA OUT 20 NM... WATERS FROM INTRACOASTAL CITY TO CAMERON LA FROM 20 TO 60 NM...WATERS FROM CAMERON LA TO HIGH ISLAND TX FROM 20 TO 60 NM...WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM. && FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.LAKECHARLES.GOV WWW.TWITTER.COM/NWSLAKECHARLES WWW.YOUTUBE.COM/NWSLAKECHARLES && $$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
946 PM CDT THU MAY 8 2014 .DISCUSSION... MOSAIC RADAR ANALYSIS SHOWING A RATHER LARGE LINE OF CONVECTION EXTENDING FROM SOUTH CENTRAL ARKANSAS THROUGH EXTREME NORTHWEST LOUISIANA AND NORTHEAST TEXAS. THIS ACTIVITY DEVELOPING WELL AHEAD OF THE SHORTWAVE TROUGH WHICH IS CURRENT ACROSS THE TX/OK PNHDL INTO THE SOUTHERN AND CENTRAL PLAINS. HRRR HAS A GOOD HANDLE ON THIS CONVECTION CONTINUING TO PUSH SOUTH AND EAST THROUGH THE NIGHT WITH RAINFALL RATES NEAR 1.5 INCHES PER HOUR ALONG THE LEADING EDGE OF THE CONVECTION. HAVE UPDATED THE FORECAST TO GO WITH CATEGORICAL POPS ACROSS THE NORTHWEST HALF FOR THE REMAINDER OF THE EVENING AND THEN ACROSS THE EASTERN HALF AFTER MIDNIGHT. ALSO ADDED THE LOCALLY HEAVY RAINFALL MODIFIER GIVEN THE RAINFALL RATES AND WHAT HAS ALREADY OCCURRED. CONCERNING TEMPERATURES...OUR NORTHWEST ZONES ARE ALREADY A DEGREE OR TWO BELOW FORECAST MINS SO LOWERED MINS BUT THESE TEMPERATURES MAY RECOVER SLIGHTLY AFTER THE CONVECTION ENDS. ALSO ADJUSTED SKY/WIND AND DEWPOINT GRIDS BASED ON CURRENT TRENDS. UPDATE ALREADY SENT...13. && .PREV DISCUSSION... /ISSUED 753 PM CDT THU MAY 8 2014/ AVIATION... A LINE OF STRONG CONVECTION WILL MOVE EAST ACROSS THE FORECAST AREA THIS EVENING AND EARLY FRIDAY MORNING. EXPECT MODERATE TO SEVERE TURBULENCE WITH THIS ACTIVITY AS WELL AS PERIODS OF IFR CIGS AND VSBYS DUE TO HEAVY RAINFALL. FOLLOWING THE LINE...CIGS WILL REMAIN MOSTLY MVFR AND OCCASIONAL LIGHTER RAINFALL AND FOG WILL REDUCE VSBYS BETWEEN 2 AND 5 MILES. CONDITIONS WILL IMPROVE AFTER 16Z FRIDAY TO VFR MOST LOCATIONS. SURFACE WIND TO REMAIN SOUTH AROUND 10 KTS TONIGHT EXCEPT WIND GUSTS TO 40 KTS ARE POSSIBLE IN AND AROUND THE CONVECTION. WIND ON FRIDAY SOUTH TO SOUTHWEST 10 TO 15 KTS. /14/ && .PRELIMINARY POINT TEMPS/POPS... SHV 68 84 67 87 68 / 80 40 20 20 20 MLU 71 82 66 86 67 / 80 50 30 20 20 DEQ 64 84 61 85 66 / 80 50 20 20 20 TXK 66 83 66 86 67 / 80 50 40 20 20 ELD 66 83 65 86 66 / 80 50 40 20 20 TYR 66 88 66 88 70 / 80 20 20 20 10 GGG 68 87 66 87 70 / 80 30 20 20 10 LFK 71 89 68 88 70 / 80 30 20 20 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 13
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
401 PM EDT WED MAY 7 2014 .SYNOPSIS... A WEAK FRONTAL BOUNDARY WILL LIFT NORTH AS A WARM FRONT TONIGHT INTO THURSDAY MORNING. HIGH PRESSURE WILL BECOME ANCHORED OFF THE SOUTHEAST COAST THURSDAY AFTERNOON THROUGH FRIDAY...AS THE FRONTAL BOUNDARY LINGERS ALONG THE MID ATLANTIC COAST. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... MID-AFTERNOON WX ANALYSIS FEATURES ~1024MB SFC HIGH PRESSURE OVER ON/QC, RIDGING SOUTHEAST INTO THE NORTHEAST/MID-ATLANTIC REGION, WITH A QUASI-STATIONARY FRONTAL BOUNDARY STILL IN PLACE FROM SE NC BACK INTO THE CENTRAL APPALACHIANS. ALOFT, UPPER AIR ANALYSIS SHOWS A DEEP TROUGH IN PLACE OVER THE INTERMOUNTAIN WEST, AND A SECOND DEPARTING TROUGH OVER ATLANTIC CANADA. MID/UPPER LEVEL RIDGE AXIS CONTINUES TO TRANSLATE EASTWARD TODAY, ORIENTED FROM THE SOUTHEAST INTO THE OHIO VALLEY. QUICK MOVING SHORTWAVE TROUGH PINWHEELED FROM WESTERN PA/MD ACROSS TO THE LOWER EASTERN SHORE BY MID AFTERNOON. MUCH OF THIS ACTIVITY HAS PUSHED OFFSHORE, BUT HAVE RETAINED SOME ISO TO SCT SHRA WORDING FOR THE BALANCE OF THE AFTN/EARLY EVENING AS THIS AREA REMAINS ON THE SOUTHERN PERIPHERY OF DEEPER LAYER MOISTURE AS UPPER RIDGE EDGES NORTHEAST THROUGH TONIGHT. OTHERWISE, EXPECT A DRY AFTN/EVENING. SW FLOW OVER THE SOUTHERN PLAINS AND SOUTHEAST WILL SHUNT THE STATIONARY FRONT BACK TO THE NORTH TNGT AND OVERNIGHT AS A WARM FRONT. A SECOND, MORE DEFINED SHORTWAVE TROUGH TRACKS THROUGH THE NW FLOW TONIGHT INTO EARLY THURSDAY. HOWEVER, AS THE UPPER RIDGE AND SFC WARM FRONT SLIP NORTH, THE BEST POTENTIAL FOR SHOWERS/TSTMS WILL SHIFT INTO PA/NJ/NRN DE/FAR NE MD. DID RETAIN A LOW POP GIVEN THAT THE EASTERN SHORE AND NRN NECK WILL REMAIN CLOSE ENOUGH TO THE MID-LEVEL FORCING TO INCLUDED A 20-30% POP BUT EXPECT MOST OF THE NIGHT TO BE DRY EVEN OVER THESE AREAS. LEANED TOWARDS HIGHER ENVELOPE OF MOS GUIDANCE GIVEN PERSISTENT MID LVL CLOUDINESS...AS WELL WHAT WILL LIKELY BE AREAS OF STRATUS ACROSS THE COASTAL PLAIN OVERNIGHT AS THE FRONT SLIPS NORTH. LOOK FOR EARLY MORNING LOWS IN THE LOWER TO MIDDLE 60S FOR MOST...U50S TO NEAR 60 EASTERN SHORE. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... CLOUDS WL GRADUALLY DECREASE FROM SW-NE THURSDAY...BUT EXPECT CLOUDS TO LINGER FOR MUCH OF THE DAY OVER THE EASTERN SHORE AS FRONT REMAINS SLOW TO LIFT ACROSS NORTHEAST COASTAL PLAIN GIVEN PERSISTENT LLVL EASTERLY FLOW OFF OF THE STILL QUITE CHILLY ATLANTIC COASTAL WATERS. MEANWHILE BEHIND THE FRONT, EXPECT THURSDAY TO BE THE WARMEST DAY OF THE YEAR SO FAR W OF THE BAY. EXPECT HIGHS RANGING FROM THE MID 80S TO AROUND 90. HIGHS OVER THE EASTERN SHORE SHOULD RANGE FROM THE LOW/MID 70S ALONG THE IMMEDIATE ATLANTIC COAST...TO THE UPPER 70S/AROUND 80 INLAND. THE FRONT MAY ACTUALLY DROP BACK S INTO THE EASTERN SHORE AS A BACKDOOR COLD FRONT THURSDAY NIGHT INTO EARLY FRIDAY...BEFORE RETREATING NNE FRIDAY AFTERNOON. NAM/GFS BUFR AT SBY SOUNDINGS SUGGEST SOME STRATUS COULD COME INLAND FROM THE OCEAN. THIS AND THE ULTIMATE PLACEMENT OF THE FRONT WILL HAVE A LARGE INFLUENCE ON HIGHS FRIDAY. WITH UPPER RIDGING IN PLACE FROM THE MID-ATLANTIC WELL NORTH INTO EASTERN CANADA, AND SURFACE HIGH ALONG/JUST OFFSHORE...EXPECT ANOTHER VERY WARM TO HOT DAY INLAND ON SW WINDS. ALSO LOOK FOR A BIT MORE IN THE WAY OF INSTABILITY, AS HIGH RES MODELS ARE BEGINNING TO HOOK ON TO SOME SUBTLE LEE TROUGHING FRIDAY AFTN/EVENING. GIVEN THAT DOWNSLOPE FLOW MAY WELL MAKE IT TOO DRY FOR WIDESPREAD OR EVEN ORGANIZED CONVECTIVE DEVELOPMENT, WILL CAP POP AT SILENT FOR RIGHT NOW. HOWEVER, WILL NEED TO KEEP AN EYE OUT FOR SOME ISOLATED, DISORGANIZED CONVECTION FIRING ACROSS THE WEST ON FRIDAY AFTN/EVENING. HIGHS WARM RIGHT BACK INTO THE 80S TO NEAR 90 WEST OF THE BAY...WITH U70S TO LOWER 80S OVER THE EASTERN SHORE. GOOD AGREEMENT AMONGST MODELS IN WASHING OUT NEXT COLD FRONT TO THE WEST IN WARM/DRY QUASI-ZONAL FLOW. WILL SEE A BIT MORE IN THE WAY OF SOME DIURNALLY DRIVEN, WIDELY SCT THUNDERSTORMS. HOWEVER, ONCE AGAIN DYNAMICS AND INSTABILITY OVER OUR REGION APPEAR AS IF THEY WILL BE RATHER MEAGER. HIGHS GENERALLY BACK INTO THE 80S INLAND...70S TO NEAR 80 OVER THE EASTERN SHORE. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... EARLY SUMMER PATTERN SETTING UP AS BERMUDA RIDGE HOLDS FIRM ACROSS THE AREA THRU MID WEEK. WASHED OUT FRONTAL BOUNDARY WILL COMBINE WITH ANY RESIDUAL CONVECTIVE BOUNDARIES SUN THRU TUES. UPSHOT WILL BE LOW CHCS (20-30%) FOR AFTN/EVENING SHRAS/TSTMS EACH DAY. HIGHS SUN U70S-L80S XCPT L-M70S AT THE BEACHES. HIGH MON/TUES 80-85...XCPT 75-80 CSTL AREAS. LOWS GNRLY 60-65. MODELS DEPICT NEXT FRONTAL BOUNDARY CROSSING THE AREA WED. THIS PRBLY THE BEST CHC FOR ANY WDSPRD PCPN AS IT APPEARS THAT SOME TROPICAL MSTR GETS TRANSPORTED NORTH ALONG IT. KEPT POPS IN CHC CATEGORY FOR NOW GIVEN 7 DAYS OUT. HIGHS WED 75-80. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... THE FRONTAL BOUNDARY TO THE SOUTH WILL SLOWLY MOVE BACK NORTH STARTING TONIGHT. THE 85H FRONTAL IS MOVING NORTH OF THE AREA THIS AFTERNOON. THIS HAD SOME SHOWERS AND THUNDERSTORMS WHICH MOVED INTO THE DELMARVA THIS AFTERNOON. THE 85H FRONT WILL BE WELL NORTH OF THE AREA LATER TONIGHT SO ANY SHOWERS THAT FORM ALONG IT WILL BE TO THE NORTH OF THE AREA. THE FRONT TO THE SOUTH HAS SOME LOW LEVEL MOISTURE WITH IT. THIS COULD BRING CIGS DOWN TO MVFR OVERNIGHT TONIGHT AS THE BOUNDARY SLOWLY WORKS NORTH. LOOKING AT RUC AND NAM ON BUFKIT CAN SEE CLOUDS LOWERING AFTER MIDNIGHT ACROSS ALL TAF SITES. NOT COMPLETELY CONVINCED THE ALL THIS LOW LEVEL MOISTURE WILL RETURN. SO WILL ONLY BRING MVFR CONDITIONS IN AFTER MIDNIGHT THROUGH SUNRISE. POTENTIAL FOR THESE CLOUDS TO BE LOWER LATE TONIGHT AND AT SUNRISE. AFTER SUNRISE CLOUDS RISE QUICKLY AND DISSIPATE AT ALL SITES AS THE WARM FRONT MOVES NORTH OF THE AREA. THIS WILL ALLOW FOR VFR CONDITIONS ON THURSDAY. EXPECT MAINLY VFR CONDITIONS THROUGH THE WEEKEND BUT SCATTERED THUNDERSTORMS WILL DEVELOP BOTH SATURDAY AND SUNDAY AFTERNOON WHICH COULD BE IFR CONDITIONS FOR A SHORT TIME TO THE TAF SITES. && .MARINE... SFC PRESSURE GRADIENT BTWN THE S/W TO THE NORTH AND FRNTL BNDRY TO THE SOUTH RESULTING IN WINDS AROUND 15 KT WITH A FEW GUSTS TO 20 KTS OVER THE SRN MOST PART OF THE CHES BAY ATTM. THESE CNDTNS XPCTD TO CONT THRU LATE AFTRN BEFORE DMNSHG TONIGHT. NO SCA ANTICIPATED ATTM. WARM FRONT PROGGED TO LIFT NORTH OVER THE WATERS TONIGHT AND THU. FLOW BECOMES S-SW AND PREVAILS THRU THE WEEKEND AS HIGH PRESSURE ANCHORS OVER THE WRN ATLANTIC. WINDS AOB 15 KTS...SEAS 2-4 FT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...AJZ/MAM LONG TERM...MPR AVIATION...JAB MARINE...SAM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
258 PM EDT WED MAY 7 2014 .SYNOPSIS... A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS NORTH CAROLINA TODAY. THE FRONT LIFTS NORTH AS A WARM FRONT TONIGHT INTO THURSDAY MORNING. HIGH PRESSURE WILL BECOME ANCHORED OFF THE SOUTHEAST COAST THURSDAY AFTERNOON THROUGH FRIDAY...AS THE FRONTAL BOUNDARY LINGERS ALONG THE MID ATLANTIC COAST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MID-MORNING WX ANALYSIS FEATURES ~1024MB SFC HIGH PRESSURE OVER JAMES BAY NOSING SOUTH INTO THE NORTHEAST/MID-ATLANTIC REGION, WITH A QUASI-STATIONARY FRONTAL BOUNDARY DRAPED WELL SOUTH INTO THE CAROLINAS. ALOFT, WV/IR IMAGERY SHOWING UPPER LEVEL RIDGE AXIS EXTENDING FROM THE SOUTHEAST INTO THE TN RVR VALLEY THIS MORNING...WITH A DEEP TROUGH IN PLACE OVER THE INTERMOUNTAIN WEST, AND A SECOND DEPARTING TROUGH OVER ATLANTIC CANADA. CONTINUING TO SEE SOME CLUSTERS OF CONVECTIVE SHRAS/ISO T IN ASSOCIATION WITH SHORTWAVE ENERGY EJECTING FROM THE TROUGH OVER THE WEST. THIS ACTIVITY IS EXPECTED TO RIDE THE NW FLOW PATTERN ALOFT FROM W PA INTO THE MID ATLANTIC REGION BY THIS AFTN. WHILE DYNAMICS ARE LESS THAN FAVORABLE FOR ANY SIGNIFICANT/WIDESPREAD TSTM DEVELOPMENT (DIMINISHING EFFECTIVE SHEAR/PERSISTENT MID- LEVEL CAPPING/MODEST MLCAPE <500 J/KG), EXPECT SOME SCT SHRAS WL MAKE IT ACROSS AS WEAKENING VORTMAX SWINGS ACROSS THE MASON-DIXON LINE THROUGH THIS AFTN. LATEST HRRR SEEMS TO BE PERFORMING WELL ALONGSIDE LATEST SAT/RADAR TRENDS, AND HV THEREFORE INSTALLED SOME CHC/"SCT" POPS FOR EASTERN SHORE COUNTIES AND FAR NE VA NORTHERN NECK COUNTIES, MAINLY ALONG AND NORTH OF US-360. OTEHRWISE, EXPECT A DRY DAY FOR MOST OF THE AREA, WITH LITTLE OR NO FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT. DEVELOPING SW FLOW OVER THE SOUTHERN PLAINS AND SOUTHEAST SHOULD ALLOW THE STATIONARY FRONT TO SHIFT BACK TO THE NORTH THIS AFTN/TNGT AS A WARM FRONT, WITH MID-HIGH CLOUDS MOVING FROM SW-NE THROUGH THE DAY. HOWEVER, THE FRONT SHOULD REMAIN S OF THE LOCAL AREA THROUGH 00Z/8P EDT. HIGHS SHOULD RANGE FROM THE UPPER 60S TO AROUND 70 OVER THE EASTERN SHORE...TO THE MID/UPPER 70S FROM INTERIOR NE NC TO CENTRAL VA. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... THE STATIONARY FRONT LIFTS NNE LATE TONIGHT INTO THURSDAY MORNING THROUGH MOST OF THE AREA...BEFORE STALLING IN VICINITY OF THE LOWER MD EASTERN SHORE. A SECOND, MORE DEFINED SHORTWAVE TROUGH TRACKS THROUGH THE NW FLOW TONIGHT INTO EARLY THURSDAY. THE BEST POTENTIAL FOR SHOWERS/TSTMS WILL BE OVER PA/NJ/NRN DE/FAR NE MD. HOWEVER...PORTIONS OF THE LOCAL AREA (EASTERN SHORE AND NRN NECK) ARE CLOSE ENOUGH TO THE MID-LEVEL FORCING TO INCLUDED A 20-30% POP. THUNDER WILL BE INCLUDED BASED ON UPSTREAM ACTIVITY...MODESTLY STEEP MID-LEVEL LAPSE RATES...AND THETA-E RIDGING EXTENDING N FROM THE SUBTROPICAL WRN ATLANTIC. CLOUDS SHOULD GRADUALLY DECREASE FROM SW-NE THURSDAY...BUT THE LOWER MD EASTERN SHORE COULD REMAIN MOSTLY CLOUDY THROUGH THE DAY. THURSDAY HAS THE POTENTIAL TO BE THE WARMEST DAY OF THE YEAR SO FAR W OF THE BAY...WITH HIGHS RANGING FROM THE MID 80S TO AROUND 90. HIGHS OVER THE EASTERN SHORE SHOULD RANGE FROM THE LOW/MID 70S ALONG THE IMMEDIATE ATLANTIC COAST...TO THE UPPER 70S/AROUND 80 INLAND. THE FRONT MAY ACTUALLY DROP BACK S INTO THE EASTERN SHORE AS A BACKDOOR COLD FRONT THURSDAY NIGHT INTO EARLY FRIDAY...BEFORE RETREATING NNE FRIDAY AFTERNOON. THIS WILL MAKE FOR A CHALLENGING TEMPERATURE/SKY COVER FORECAST. NAM/GFS BUFR AT SBY SOUNDINGS SUGGEST SOME STRATUS COULD COME INLAND FROM THE OCEAN. THIS AND THE ULTIMATE PLACEMENT OF THE FRONT WILL HAVE A LARGE INFLUENCE ON HIGHS FRIDAY. THE CURRENT FORECAST IS FOR HIGHS AROUND 70 ALONG THE COAST...TO MID/UPPER 70S FOR INTERIOR PORTIONS. ELSEWHERE...EXPECT A SUNNY AND WARM DAY WITH HIGHS IN THE MID/UPPER 80S (LOCALLY LOW 80S COASTAL SE VA/NE NC). && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... BERMUDA HIGH PRESSURE REMAINS ANCHORED OFF THE SERN COAST THROUGH THE WEEKEND. LATEST MODEL DATA SLOWS THE APPRCH OF NEXT FRNT ACROSS THE MTS UNTIL SUNDAY. KEPT FRI NIGHT/SAT MORNING DRY. SCT CONVECTION PSBL INVOF LEE TROF RESULTING IN DIURNAL POPS SAT AFTN/EVE. LOWS FRI NIGHT L-M60S. HIGHS SAT 80-85...XCPT M-U70S COASTAL AREAS. FRONT APPRCHS THE AREA SAT NIGHT THEN WEAKENS/WASHES OUT ACROSS THE MID ATLNTC RGN SUNDAY. HOWEVER...MODELS NOW WANT TO KEEP THIS WEAKEN BNDRY/TROF HANGING ARND THE RGN THROUGH ERLY NEXT WEEK. GIVEN THIS TRIGGER...KEPT CHC SHWRS/TSTMS (20-40%...HIGHEST W OF BAY) IN FCST THROUGH THE PRD. HIGHS EACH DAY 80-85 EXCEPT REMAINING IN THE 70S COASTAL SECTIONS. LOWS U50S-M60S. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... THE FRONTAL BOUNDARY TO THE SOUTH WILL SLOWLY MOVE BACK NORTH STARTING TONIGHT. THE 85H FRONTAL IS MOVING NORTH OF THE AREA THIS AFTERNOON. THIS HAD SOME SHOWERS AND THUNDERSTORMS WHICH MOVED INTO THE DELMARVA THIS AFTERNOON. THE 85H FRONT WILL BE WELL NORTH OF THE AREA LATER TONIGHT SO ANY SHOWERS THAT FORM ALONG IT WILL BE TO THE NORTH OF THE AREA. THE FRONT TO THE SOUTH HAS SOME LOW LEVEL MOISTURE WITH IT. THIS COULD BRING CIGS DOWN TO MVFR OVERNIGHT TONIGHT AS THE BOUNDARY SLOWLY WORKS NORTH. LOOKING AT RUC AND NAM ON BUFKIT CAN SEE CLOUDS LOWERING AFTER MIDNIGHT ACROSS ALL TAF SITES. NOT COMPLETELY CONVINCED THE ALL THIS LOW LEVEL MOISTURE WILL RETURN. SO WILL ONLY BRING MVFR CONDITIONS IN AFTER MIDNIGHT THROUGH SUNRISE. POTENTIAL FOR THESE CLOUDS TO BE LOWER LATE TONIGHT AND AT SUNRISE. AFTER SUNRISE CLOUDS RISE QUICKLY AND DISSIPATE AT ALL SITES AS THE WARM FRONT MOVES NORTH OF THE AREA. THIS WILL ALLOW FOR VFR CONDITIONS ON THURSDAY. EXPECT MAINLY VFR CONDITIONS THROUGH THE WEEKEND BUT SCATTERED THUNDERSTORMS WILL DEVELOP BOTH SATURDAY AND SUNDAY AFTERNOON WHICH COULD BE IFR CONDITIONS FOR A SHORT TIME TO THE TAF SITES. && .MARINE... STALLED FRONTAL BOUNDARY REMAINS DRAPED OVER THE CAROLINAS AS HIGH PRESSURE OVER SE CANADA RIDGES SWD OVER THE WATERS. THE RESULT IS LIGHT SELY FLOW AOB 10 KT OVER THE WATERS WITH WAVES AND SEAS GENERALLY 1-2 FT. HIGH PRESSURE LOCATES JUST OFF THE MID-ATLANTIC COAST THIS AFTERNOON AS THE STALLED FRONTAL BOUNDARY BEGINS TO LIFT NWD AS A WARM FRONT. AS THIS OCCURS...A WEAK WAVE OF LOW PRESSURE WILL LIFT ALONG THE FRONT...RESULTING IN A STRENGTHENING PRESSURE GRADIENT OVER THE WATERS. WINDS ALOFT WILL INCREASE TO 20-25 KT...BUT COOL WATERS AND WARM TEMPS ALOFT WILL RESULT IN AN INVERSION OVER THE WATERS...PREVENTING THE STRONGER WINDS FROM MIXING TO THE WATER. HOWEVER...ENOUGH OF A SFC PRESSURE GRADIENT WILL RESULT IN WINDS AROUND 15 KT OVER THE BAY LATE TODAY INTO EARLY TONIGHT BEFORE DIMINISHING AFTER MIDNIGHT. A FEW GUSTS UP TO 18-20 KT ARE POSSIBLE...BUT SCA CONDITIONS ARE NOT ANTICIPATED. WARM FRONT LIFTS OVER THE WATERS TONIGHT INTO THURS...WITH FLOW BECOMING S-SW BEHIND THE FRONT. SW FLOW PREVAILS THRU THE WEEKEND AS HIGH PRESSURE ANCHORS OVER THE WRN ATLANTIC...RESULTING IN ONGOING SUB-SCA CONDITIONS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ/MAM SHORT TERM...AJZ LONG TERM...MPR AVIATION...JAB MARINE...SAM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
943 AM EDT WED MAY 7 2014 .SYNOPSIS... A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS NORTH CAROLINA TODAY. THE FRONT LIFTS NORTH AS A WARM FRONT TONIGHT INTO THURSDAY MORNING. HIGH PRESSURE WILL BECOME ANCHORED OFF THE SOUTHEAST COAST THURSDAY AFTERNOON THROUGH FRIDAY...AS THE FRONTAL BOUNDARY LINGERS ALONG THE MID ATLANTIC COAST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MID-MORNING WX ANALYSIS FEATURES ~1024MB SFC HIGH PRESSURE OVER JAMES BAY NOSING SOUTH INTO THE NORTHEAST/MID-ATLANTIC REGION, WITH A QUASI-STATIONARY FRONTAL BOUNDARY DRAPED WELL SOUTH INTO THE CAROLINAS. ALOFT, WV/IR IMAGERY SHOWING UPPER LEVEL RIDGE AXIS EXTENDING FROM THE SOUTHEAST INTO THE TN RVR VALLEY THIS MORNING...WITH A DEEP TROUGH IN PLACE OVER THE INTERMOUNTAIN WEST, AND A SECOND DEPARTING TROUGH OVER ATLANTIC CANADA. CONTINUING TO SEE SOME CLUSTERS OF CONVECTIVE SHRAS/ISO T IN ASSOCIATION WITH SHORTWAVE ENERGY EJECTING FROM THE TROUGH OVER THE WEST. THIS ACTIVITY IS EXPECTED TO RIDE THE NW FLOW PATTERN ALOFT FROM W PA INTO THE MID ATLANTIC REGION BY THIS AFTN. WHILE DYNAMICS ARE LESS THAN FAVORABLE FOR ANY SIGNIFICANT/WIDESPREAD TSTM DEVELOPMENT (DIMINISHING EFFECTIVE SHEAR/PERSISTENT MID- LEVEL CAPPING/MODEST MLCAPE <500 J/KG), EXPECT SOME SCT SHRAS WL MAKE IT ACROSS AS WEAKENING VORTMAX SWINGS ACROSS THE MASON-DIXON LINE THROUGH THIS AFTN. LATEST HRRR SEEMS TO BE PERFORMING WELL ALONGSIDE LATEST SAT/RADAR TRENDS, AND HV THEREFORE INSTALLED SOME CHC/"SCT" POPS FOR EASTERN SHORE COUNTIES AND FAR NE VA NORTHERN NECK COUNTIES, MAINLY ALONG AND NORTH OF US-360. OTEHRWISE, EXPECT A DRY DAY FOR MOST OF THE AREA, WITH LITTLE OR NO FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT. DEVELOPING SW FLOW OVER THE SOUTHERN PLAINS AND SOUTHEAST SHOULD ALLOW THE STATIONARY FRONT TO SHIFT BACK TO THE NORTH THIS AFTN/TNGT AS A WARM FRONT, WITH MID-HIGH CLOUDS MOVING FROM SW-NE THROUGH THE DAY. HOWEVER, THE FRONT SHOULD REMAIN S OF THE LOCAL AREA THROUGH 00Z/8P EDT. HIGHS SHOULD RANGE FROM THE UPPER 60S TO AROUND 70 OVER THE EASTERN SHORE...TO THE MID/UPPER 70S FROM INTERIOR NE NC TO CENTRAL VA. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... THE STATIONARY FRONT LIFTS NNE LATE TONIGHT INTO THURSDAY MORNING THROUGH MOST OF THE AREA...BEFORE STALLING IN VICINITY OF THE LOWER MD EASTERN SHORE. A SECOND, MORE DEFINED SHORTWAVE TROUGH TRACKS THROUGH THE NW FLOW TONIGHT INTO EARLY THURSDAY. THE BEST POTENTIAL FOR SHOWERS/TSTMS WILL BE OVER PA/NJ/NRN DE/FAR NE MD. HOWEVER...PORTIONS OF THE LOCAL AREA (EASTERN SHORE AND NRN NECK) ARE CLOSE ENOUGH TO THE MID-LEVEL FORCING TO INCLUDED A 20-30% POP. THUNDER WILL BE INCLUDED BASED ON UPSTREAM ACTIVITY...MODESTLY STEEP MID-LEVEL LAPSE RATES...AND THETA-E RIDGING EXTENDING N FROM THE SUBTROPICAL WRN ATLANTIC. CLOUDS SHOULD GRADUALLY DECREASE FROM SW-NE THURSDAY...BUT THE LOWER MD EASTERN SHORE COULD REMAIN MOSTLY CLOUDY THROUGH THE DAY. THURSDAY HAS THE POTENTIAL TO BE THE WARMEST DAY OF THE YEAR SO FAR W OF THE BAY...WITH HIGHS RANGING FROM THE MID 80S TO AROUND 90. HIGHS OVER THE EASTERN SHORE SHOULD RANGE FROM THE LOW/MID 70S ALONG THE IMMEDIATE ATLANTIC COAST...TO THE UPPER 70S/AROUND 80 INLAND. THE FRONT MAY ACTUALLY DROP BACK S INTO THE EASTERN SHORE AS A BACKDOOR COLD FRONT THURSDAY NIGHT INTO EARLY FRIDAY...BEFORE RETREATING NNE FRIDAY AFTERNOON. THIS WILL MAKE FOR A CHALLENGING TEMPERATURE/SKY COVER FORECAST. NAM/GFS BUFR AT SBY SOUNDINGS SUGGEST SOME STRATUS COULD COME INLAND FROM THE OCEAN. THIS AND THE ULTIMATE PLACEMENT OF THE FRONT WILL HAVE A LARGE INFLUENCE ON HIGHS FRIDAY. THE CURRENT FORECAST IS FOR HIGHS AROUND 70 ALONG THE COAST...TO MID/UPPER 70S FOR INTERIOR PORTIONS. ELSEWHERE...EXPECT A SUNNY AND WARM DAY WITH HIGHS IN THE MID/UPPER 80S (LOCALLY LOW 80S COASTAL SE VA/NE NC). && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... BERMUDA HIGH PRESSURE REMAINS ANCHORED OFF THE SERN COAST THROUGH THE WEEKEND. LATEST MODEL DATA SLOWS THE APPRCH OF NEXT FRNT ACROSS THE MTS UNTIL SUNDAY. KEPT FRI NIGHT/SAT MORNING DRY. SCT CONVECTION PSBL INVOF LEE TROF RESULTING IN DIURNAL POPS SAT AFTN/EVE. LOWS FRI NIGHT L-M60S. HIGHS SAT 80-85...XCPT M-U70S COASTAL AREAS. FRONT APPRCHS THE AREA SAT NIGHT THEN WEAKENS/WASHES OUT ACROSS THE MID ATLNTC RGN SUNDAY. HOWEVER...MODELS NOW WANT TO KEEP THIS WEAKEN BNDRY/TROF HANGING ARND THE RGN THROUGH ERLY NEXT WEEK. GIVEN THIS TRIGGER...KEPT CHC SHWRS/TSTMS (20-40%...HIGHEST W OF BAY) IN FCST THROUGH THE PRD. HIGHS EACH DAY 80-85 EXCEPT REMAINING IN THE 70S COASTAL SECTIONS. LOWS U50S-M60S. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... STALLED FRONTAL BOUNDARY REMAINS DRAPED OVER THE CAROLINAS AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. A WEAK WAVE IN NWLY FLOW ALOFT IS PRODUCING BKN-OVC SKIES WITH DECKS GENERALLY 6-10K FT AGL EARLY THIS MORNING. OTHERWISE...WINDS GENERALLY CALM- LESS THAN 5 KT. FOR TODAY...VFR CONDITIONS PREVAIL AS HIGH PRESSURE BUILDS OFFSHORE. ADDITIONAL UPPER LEVEL WAVE WILL KEEP SCT-BKN MID LEVEL CLOUDS AROUND...WITH SOME SCT-BKN LOWER MID-LEVEL CLOUDS (3-5K FT AGL) OVER SE VA/NE NC. SE WINDS REMAIN GENERALLY AOB 10 KT. FRONTAL BOUNDARY WILL BEGIN TO LIFT NWD TONIGHT AS A WARM FRONT...WITH SOME STRATUS POSSIBLE. HOWEVER...MOISTURE RETURN WILL BE LIMITED...SO DO NOT ANTICIPATE WIDESPREAD STRATUS. THEREAFTER...VFR CONDITIONS ARE EXPECTED THROUGH THE END OF THE WEEK. THERE IS A SLIGHT TO LOW END CHANCE OF SHOWERS/THUNDERSTORMS OVER THE MD ERN SHORE...INCLUDING KSBY TONIGHT AND THURSDAY. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS ARE IN PLACE SUNDAY. && .MARINE... STALLED FRONTAL BOUNDARY REMAINS DRAPED OVER THE CAROLINAS AS HIGH PRESSURE OVER SE CANADA RIDGES SWD OVER THE WATERS. THE RESULT IS LIGHT SELY FLOW AOB 10 KT OVER THE WATERS WITH WAVES AND SEAS GENERALLY 1-2 FT. HIGH PRESSURE LOCATES JUST OFF THE MID-ATLANTIC COAST THIS AFTERNOON AS THE STALLED FRONTAL BOUNDARY BEGINS TO LIFT NWD AS A WARM FRONT. AS THIS OCCURS...A WEAK WAVE OF LOW PRESSURE WILL LIFT ALONG THE FRONT...RESULTING IN A STRENGTHENING PRESSURE GRADIENT OVER THE WATERS. WINDS ALOFT WILL INCREASE TO 20-25 KT...BUT COOL WATERS AND WARM TEMPS ALOFT WILL RESULT IN AN INVERSION OVER THE WATERS...PREVENTING THE STRONGER WINDS FROM MIXING TO THE WATER. HOWEVER...ENOUGH OF A SFC PRESSURE GRADIENT WILL RESULT IN WINDS AROUND 15 KT OVER THE BAY LATE TODAY INTO EARLY TONIGHT BEFORE DIMINISHING AFTER MIDNIGHT. A FEW GUSTS UP TO 18-20 KT ARE POSSIBLE...BUT SCA CONDITIONS ARE NOT ANTICIPATED. WARM FRONT LIFTS OVER THE WATERS TONIGHT INTO THURS...WITH FLOW BECOMING S-SW BEHIND THE FRONT. SW FLOW PREVAILS THRU THE WEEKEND AS HIGH PRESSURE ANCHORS OVER THE WRN ATLANTIC...RESULTING IN ONGOING SUB-SCA CONDITIONS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ/MAM SHORT TERM...AJZ LONG TERM...MPR AVIATION...SAM MARINE...SAM
AREA FORECAST DISCUSSION...CORRECTED
NWS BALTIMORE MD/WASHINGTON DC
407 AM EDT WED MAY 7 2014 .SYNOPSIS... A STATIONARY FRONT JUST SOUTH OF THE AREA WILL RETURN NORTH AS A WARM FRONT TODAY. HOWEVER...HIGH PRESSURE BUILDING IN FROM THE NORTH WILL LIMIT PROGRESSION OF THE FRONT THROUGH THE AREA AND INSTEAD AN ONSHORE FLOW WILL DEVELOP AS THE HIGH PRESSURE DRIFTS OFFSHORE. THE FRONT MAY SAG SOUTHWARD AS A BACKDOOR COLD FRONT THURSDAY NIGHT. HIGH PRESSURE WILL REMAIN PARKED OFF THE SOUTHEAST COAST LATE IN THE WEEK AND THIS WEEKEND WITH SOUTHERLY RETURN FLOW YIELDING WARM AND HUMID CONDITIONS. && .NEAR TERM /THROUGH THURSDAY/... AS OF 08Z...1025MB SFC HIGH SOUTH OF JAMES BAY IN QUEBEC. A STATIONARY SFC FRONT IS CURRENTLY OVER CENTRAL VA...THOUGH IT IS DIFFICULT TO PINPOINT FROM SFC OBS/RADAR/SATELLITE. LIGHT SHOWERS OVER SWRN ZONES HAVE DISSIPATED FOR NOW...BUT REDEVELOPMENT IS EXPECTED. WITH MID LEVEL LAPSE RATES AROUND 6 C/KM...ELEVATED THUNDERSTORM DEVELOPMENT IS STILL POSSIBLE...WARRANTING AN ISOLATED THUNDER MENTION. WILL HAVE TO WATCH THE CONVECTIVE COMPLEX OVER MI/NWRN OH THAT WILL CONTINUE TO SHIFT SOUTHEAST IN ELEVATED UNSTABLE AIR. SPC MESOANALYSIS HAS 500 MUCAPE EXTENDING SOUTHEAST ACROSS THE SWRN HALF OF THE LWX CWA SO AS OF NOW THIS WOULD SPREAD ACROSS THE CENTRAL OR SOUTHERN PORTION OF THE CWA LATE THIS MORNING THROUGH MIDDAY. 06Z HRRR DEPICTS SOME REMNANTS CROSSING NRN/CNTRL PARTS OF THE CWA FROM 10 AM TO 2PM. THIS WILL ALL BE CLOSELY MONITORED WITH GRID UPDATES AS NECESSARY. TODAY...WARM FRONT LIFTS NORTH INTO THE AREA WITH CHANCE POPS SPREADING ACROSS THE DC METRO AREA THROUGH MIDDAY. HOWEVER...AS THE CANADIAN SFC HIGH PRESSURE SHIFTS SSE ACROSS NJ THIS AFTERNOON...AN ONSHORE FLOW DEVELOPS FOR THE WRN SHORE. A VORTMAX RIDES THE NWLY FLOW AS WELL...ALLOWING CHANCE POPS ACROSS NERN MD LATE THIS AFTERNOON AND EVENING (MAY BE EARLIER WITH ONGOING ACTIVITY ENTERING OHIO). MAX TEMP UNCERTAINTY TODAY DUE TO TIMING QUESTION OF WARM FRONT AND ONSHORE FLOW. MAV/MET/GMOS BLEND GAVE GREATER BALTIMORE AROUND 70F...SLOWLY INCREASING SW FROM THERE WITH MID 70S IN SHEN VLY AND VLYS WEST OF THERE. SFC HIGH SETS UP SSE OF DC WITH A SLY FLOW THEN THROUGH THURSDAY. MAINLY DRY THURSDAY WITH INCREASING TEMPS. QUESTION IS IF ONSHORE FLOW COMPONENT CAN HANG ON. THEREFORE...LOW 70S IN FOR HARFORD WITH LOW TO MID 80S FOR MOST OF THE REST OF THE CWA. WILL NEED TO WATCH FOR 90F IN SOUTHEAST. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... UPPER RIDGE AXIS PROGRESSES EWD OVER THE REGION THU NGT AND FRI MRNG. MODELS CONTINUE TO ADVERTISE HIPRES OFF THE NEW ENGLAND COAST RIDGING SWWD INTO THE AREA THU NGT AND A BACKDOOR COLD FRONT TO PUSH THRU NORTH-CENTRAL MD. ONSHORE FLOW ON THE COOL SIDE OF THE BOUNDARY COULD RESULT IN DEVELOPMENT OF STRATUS AND PATCHY DRIZZLE THU NGT. SWLY FLOW WILL STRENGTHEN ON FRI AS THE RIDGE AXIS MOVES OFFSHORE AND AN UPSTREAM TROUGH APPROACHES FROM THE CENTRAL CONUS. THE HIGH SUN ANGLE WILL CONTRIBUTE TO STRONG HEATING...ALLOWING ANY STRATUS EAST OF THE BLUE RIDGE TO MIX OUT BY MIDDAY. WARM AIRMASS UNDERNEATH THE RIDGE CHARACTERIZED BY +2SD 925 MB TEMPS WILL YIELD HIGHS IN THE 80S. DID RAISE MAX TEMPS A BIT ON FRI WITH SOME WARMER SPOTS IN CENTRAL VA HAVING THE POTENTIAL TO REACH 90F ASSUMING FULL HEATING. SUBSIDENCE INVERSION WEAKENS FRI AFTN AND FRI NGT IN ASSOCIATION WITH HEIGHT FALLS AHEAD OF THE APPROACHING TROUGH WILL HELP ERODE THE SUBSIDENCE INVERSION. MODELS SHOWING SOME POTENTIAL FOR CONVECTIVE DEVELOPMENT OVER THE MTS DURING THE PEAK HEATING HRS IN ASSOCIATION WITH LIFT FROM A LEADING MID-LVL SHORTWAVE ENERGY AND SFC PRESSURE TROUGH. INTRODUCED ISO COVERAGE OF TSTMS DURING THE AFTN AND EVE WITH SBCAPE AROUND 1000 J/KG. SHOWERS MAY SPREAD EWD TOWARD I-95 DURING THE EVE BEFORE MOST OF THE ACTIVITY WANES OVERNIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... MID- AND UPPER-LVL FLOW WILL FLATTEN OUT THIS WEEKEND AS THE MAIN ENERGY ASSOCIATED WITH AN UPPER TROUGH AND SFC LOW LIFTING NEWD INTO QUEBEC. A SWLY LLVL JET AHEAD OF THE TROUGH AND ON THE BACKSIDE OF THE BERMUDA HIGH WILL DRAW MOISTURE FROM THE GULF OF MEXICO TOWARD THE MID-ATLANTIC REGION. SHOWERS ARE LIKELY ON SAT AS FORCING FOR ASCENT WITH A SHORTWAVE TROUGH AND WITHIN RIGHT-ENTRANCE REGION OF ULVL JET STREAK SPREADING INTO THE AREA. CHANCE POPS OVER THE NRN PIEDMONT AND SRN MD INCREASE TO LIKELY N/W OF DC TO CATEGORICAL ALONG THE ALLEGHENY FRONT. KEPT AFTN TSTM COVERAGE ISO DUE TO FCST UNCERTAINTY WITH CLOUD COVER OVER THE AREA. MODEL SOUNDINGS FROM THE 00Z GFS SHOW A RATHER CLOUDY AND STABLE AIRMASS ON SAT WHILE THE 00Z ECMWF DEPICTS A GREATER POTENTIAL FOR HEATING AND TSTMS. SYNOPTIC PATTERN EXPECTED TO BECOME FAIRLY ZONAL ACROSS THE ERN HALF OF THE CONUS SUN AND MON. ABOVE NORMAL TEMPS AND SOMEWHAT HUMID WITH DEWPOINTS NEAR 60F) WILL CONTINUE THRU ERY NEXT WEEK WITH SLY RETURN FLOW IN THE LLVLS. ATTEMPTED TO KEEP CHANCES FOR PRECIP LOW DURING THIS TIME WITH A LACK OF ORGANIZED SYNOPTIC LIFT. A COLD FRONT WILL APPROACH FROM THE WEST MIDWEEK. STILL PLENTY OF DIFFERENCES BETWEEN TIMING OF FROPA. FCST FOLLOWS WPC GUIDANCE... GIVING US INCREASING CHANCES FOR SHOWERS AND STORMS TUE. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... MID LEVEL CLOUDS INCREASE AS WARM FRONT APPROACHES FROM THE SOUTH. WILL HAVE TO WATCH THUNDERSTORMS MOVING SOUTHEAST FROM CNTRL OH IN ELEVATED UNSTABLE AIR THIS MORNING THAT WILL APPROACH SOME OF THE TERMINALS (THOUGH THIS WILL ALSO HAVE TO BE WATCHED) EARLIER THAN THE GUIDANCE WHICH PROGS LATE AFTERNOON/EVENING. ONSHORE FLOW DEVELOPS TONIGHT WITH LOW CLOUDS...NEAR IFR THURSDAY MORNING BEFORE SLY FLOW SLOWLY CLEARS THE CONDS TO VFR FOR THE REST OF THURSDAY. A BACKDOOR COLD FRONT SHOULD MOVE THRU BWI-MTN THU NGT AND POTENTIALLY REACH DCA-IAD. MVFR/IFR CIGS IN STRATUS POSSIBLE THU NGT AND FRI MRNG ON THE COLD SIDE OF THE BOUNDARY. SCT SHRA AND ISO TSTM POSSIBLE IN THE MTS FRI AFTN/EVE. BETTER COVERAGE OF SHRA EXPECTED SAT WITH A DISTURBANCE MOVING THRU THE TERMINALS. IFR VSBYS POSSIBLE IN HEAVIER SHOWERS OR STORMS. S-SW WINDS MAY GUST 15-25 KT SAT AFTN. MAINLY VFR THRU THE REMAINDER OF THE WEEKEND. && .MARINE... NELY FLOW 10 TO 15 KT OVER THE WATERS WILL BECOME ELY THIS AFTERNOON AS HIGH PRESSURE BUILDS SOUTH TO NJ. WILL NEED TO WATCH THUNDERSTORM COMPLEX OVER OHIO FOR MIDDAY THUNDERSTORM POTENTIAL FOR THE BAY WITH ELEVATED INSTABILITY ACROSS THE REGION. FLOW BECOMES ELY THIS AFTERNOON...ESELY FOR SRN MD WATERS WHICH WILL CHANNEL UP THE TIDAL POTOMAC AND POSSIBLY THE TIDAL PATUXENT THIS EVENING. MARGINAL SCA UP FOR LOWER AND MIDDLE TIDAL POTOMAC AS WELL AS LOWER SRN MD WATERS STARTING THIS AFTERNOON...EXPANDING UP TO NORTH BEACH THIS EVENING. GUST POTENTIAL IS AROUND 20 KT. FLOW BECOMES MORE LIGHT AND VARIABLE THURSDAY AS HIGH PRESSURE MOVES SOUTHEAST OF THE AREA AND A WEAK PRESSURE PATTERN OCCURS OVER THE MD PART OF THE BAY. LGT SLY WINDS LATE THIS WEEK. A SCA MAY BE NEEDED FOR THE WATERS ON SAT AS S-SWLY FLOW INCREASES AHEAD OF A TROUGH OF LOPRES. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EDT THURSDAY FOR ANZ533-542. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM EDT THURSDAY FOR ANZ534-536-537-543. && $$ SYNOPSIS...JRK NEAR TERM...BAJ SHORT TERM...JRK LONG TERM...JRK AVIATION...BAJ/JRK MARINE...BAJ/JRK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 PM EDT WED MAY 7 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 407 PM EDT WED MAY 7 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW FAIRLY HI AMPLITUDE RDG BLDG FM THE SE CONUS INTO THE UPR LKS DOWNSTREAM OF A DEEP TROF IN THE ROCKIES. THERE ARE TWO CLOSED LOWS EMBEDDED IN THE TROF. ONE LO IS CENTERED OVER SASKATCHEWAN AND THE OVER THE DESERT SW. THE LO OVER THE DESERT SW WL HAVE THE MOST IMPACT ON UPR MI WX. WARM FNT TO THE E OF ASSOCIATED LO PRES IN THE CENTRAL PLAINS IS EXTENDING E THRU IOWA TOWARD THE LOWER LKS...WITH H85 FNT MOVING N INTO SRN MN/WI. A PAIR OF ELEVATED CONVECTIVE CLUSTERS THAT MOVED ENEWD WELL N OF THE WARM FNT IMPACTED MAINLY THE SCENTRAL COUNTIES THIS MRNG/EARLY AFTN...BUT LINGERING DRY AIR BEST DEPICTED ON THE 12Z APX RAOB AND HIER STABILITY THAT IS PRESENT FARTHER TO THE N PER LATEST SPC MESOANALYSIS LIMITED THE N PUSH OF THESE SHRA/TS INTO THE CWA. ABSENCE OF DYNAMIC FORCING OTHER THAN SOME GENERAL WAD/ ISENTROPIC ASCENT UNDER BLDG UPR RDG SO FAR TO THE NE OF MAIN FORCING MECHANISM CLOSER TO THE DESERT SW UPR LO IS RESULTING IN MAINLY DRY WX THIS AFTN...WITH MAINLY JUST THICKER HI CLDS IMPACTING AREAS AWAY FM THE SCENTRAL. MAIN FCST CONCERNS THRU THU INVOLVE POPS/ELEVATED TS CHCS AND INTENSITY TO THE N OF APRCHG SFC LO/ATTENDANT WARM FNT AS WELL AS POTENTIAL FOR FOG DVLPMNT. TNGT...UPR LO OVER THE DESERT SW IF FCST TO MOVE TO THE NE AND REACH THE WCENTRAL PLAINS BY 12Z THU. AS THE SFC LO SHIFTS SLOWLY TO THE NE AS WELL...ATTENDANT SFC WARM FNT IS FCST TO MOVE ONLY SLOWLY TO THE N INTO SCNTRL WI...BUT THE H85 FNT IS PROGGED TO LIFT MORE QUICKLY N THRU THE CWA. THE MOST APPRECIABLE DEEP LYR QVECTOR CNVGC/ UPR DVCG THAT IS NOW SUPPORTING MORE NMRS SHRA/SOME TS OVER THE NRN PLAINS INTO WRN MN IS FCST TO SWING INTO THE AREA FM THE W THIS EVNG AND IMPACT MAINLY THE NW PORTION OF THE CWA BEFORE EXITING TO THE NE LATER. AT LEAST SCT SHRA/SOME TS WL LIKELY SHIFT FARTHER TO THE ESE PARALLEL TO THE APRCHG H85 WARM FNT IN LINE WITH FCST CORFIDI VECTORS AND TOWARD STEEPER H7-5 LAPSE RATES. SINCE THE CONVECTION WL BE ELEVATED...PWAT WL BE APRCHG 200 PCT OF NORMAL AS WARMER/MOISTER AIR WITH H85 DEWPTS UP TO 12C FOLLOWING THE WARM FNT...AND FCST SDNGS IN THE MORE SATURATED AIRMASS SHOW THIN SKINNY CAPE...SUSPECT HEAVY RA WL BE THE MAIN THREAT. BUT SOME HAIL MAY FALL OVER THE STRONGER CELLS MAINLY NEAR THE SRN END OF THE SHRA AREA...WHERE FCST SDNGS SHOW STEEPER MID LVL LAPSE RATES /ALBEIT WITH A BIT MORE OF A CAP/ AND H85-3 WIND SHEAR IN THE ELEVATED UNSTABLE LYR IS AOA 40-50 KTS. THIS CAPPING WL BECOME MORE PRONOUNCED LATER FOLLOWING THE H85 WARM FROPA AND TEND TO DIMINISH POPS FM THE SW. AS THE LLVLS TO THE N OF INCRSGLY SHALLOW WARM FNT INVRN MOISTEN...EXPECT SOME FOG TO DVLP LATE...MAINLY WHERE THE EXPECTED ESE NEAR SFC FLOW UPSLOPES OFF LK MI. BUT TENDED TO CUT BACK ON THE FOG FCST TO ACCOUNT FOR STILL VERY DRY LLVLS. WITH INCRSG MSTR AND THE APRCH OF THE WARM FNT... EXPECT LTL DIURNAL TEMP FALL. THU...AS SHRTWV LIFTS TO THE NE AND INTO THE NRN PLAINS BY 00Z FRI...SFC LO IS FCST TO MOVE INTO SW MN BY 00Z FRI...WITH SFC WARM FNT TO THE E ARPCHG THE WI BORDER LATE. EXPECT PLENTY OF LO CLD TO THE N OF INCRSGLY SHALLOW WARM FNTL INVRN WITH SOME FOG AS WELL IN AREAS THAT EXPERIENCE UPSLOPE FLOW WITH THE LLVL SE WIND TO THE N OF THE FNT. BEST CHC FOR MORE NMRS SHRA/TS WL BE IN THE MRNG OVER THE NE HALF BEFORE CAPPING BEHIND H85 WARM FROPA/AREA OF DEEP LYR FORCING SHIFT TO THE NE AND GIVE WAY TO LARGER SCALE QVECTOR DVGC/ STRENGTHENING OF CAPPING INVRN. PREFER THE 12Z REGIONAL CNDN MODEL HANDLING OF THE POPS SHIFTED A BIT TO THE NE TOWARD THE LARGER SCALE FORCING AND AWAY FM LIKELY CAP. BEST CHC FOR SOME SUNSHINE WL BE OVER THE W IN THE AFTN WITH DOWNSLOPE SE WIND UNDER MID LVL CAPPING/ DRYING. HI TEMPS WL AT LEAST APRCH 70 IN THIS AREA. LINE OF SHRA/TS FED BY THIS HEATING AND CLOSER APRCH OF THE LO MAY MOVE INTO THE FAR W LATE IN THE DAY. THE CURRENT SPC OUTLOOK INDICATES FAR WRN UPR MI IS UNDER THE SLGT RISK FOR SVR STORMS. WITH SFC-6KM BULK SHEAR VALUES APRCHG 40-50KTS TOWARD 00Z IN THIS AREA AT THE TIME THE LINE OF CVNCTN MIGHT BE ARRIVING LATE IN THE DAY AHEAD OF THE SHARPER DEEP LYR QVECTOR CNVGC AND FCST MUCAPE AOA 1000J/KG...STRONGER STORMS WL BE PSBL IF SFC BASED PARCELS CAN BREAK THRU THE CAP. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 449 PM EDT WED MAY 7 2014 MODELS ADVERTISE A FAIRLY ACTIVE SPRING WEATHER PATTERN FOR THE UPPER GREAT LAKES REGION FROM LATE THIS WEEK INTO THE FIRST HALF OF NEXT WEEK AS A MEAN MID-UPPER LEVEL TROUGH PERSISTS OVER THE WESTERN HALF OF THE CONTINENT ALLOWING FOR A SERIES OF SW FLOW SHORTWAVES TO BRING PERIODIC SHOWERS TO THE FCST AREA. BEGINNING THU NIGHT INTO FRI...A SHORTWAVE NOW NEAR THE AZ/MEXICO BORDER ROUNDING THE BASE OF THE WRN CONUS TROF IS EXPECTED TO LIFT NE THROUGH THE SRN ROCKIES AND CENTRAL PLAINS TONIGHT INTO THURSDAY. MODELS INDICATE THIS SHORTWAVE AND ITS ASSOC 3H JET MAX WILL TRACK ACROSS WESTERN LAKE SUPERIOR THU NIGHT INTO FRI MORNING WITH THE BEST MID-LVL Q-VECT CONVERGENCE AND UPPER DIVERGENCE STAYING NW OF THE FCST AREA. BUT DESPITE THE LACK OF FAVORABLE DYNAMICS OVER THE AREA...THE SHORTWAVE WILL DRIVE A WARM FRONT TOWARD THE UPPER GREAT LAKES LATE THU AND THEN PUSH THE SFC LOW AND ASSOC COLD FRONT INTO THE WRN PORTION OF THE CWA LATE THU NIGHT INTO EARLY FRI INCREASING LOW-LVL CONVERGENCE. DEPENDING ON EVOLUTION OF CONVECTION ALONG INCOMING WARM FRONT...POOLING OF LOW-LVL MOISTURE AND SOME ELEVATED INSTABILITY TO NEAR 500 J/KG ALONG WITH BULK SHEAR VALUES TO NEAR 40 KT COULD RESULT IN SOME STRONGER STORMS MAINLY NEAR THE WI BDR COUNTIES THU EVENING. HOWEVER...GIVEN HOW CAPPED LOW- LEVELS ARE FROM FCST SNDGS WOULD THINK THREAT OF SVR WOULD BE PRETTY MINIMAL. OTHERWISE...WEAKENING INSTABILITY SHOULD RESULT IN JUST A GENERAL THUNDERSTORM RISK LATE THU NIGHT INTO FRIDAY ALONG AND AHEAD OF COLD FRONTAL PASSAGE. FRI NIGHT AND SATURDAY...EXPECT DRIER CONDITIONS AS A MID-LVL SHORTWAVE RIDGE AND ASSOC SFC RDG BUILD IN FM WEST BEHIND THE FRIDAYS FRONTAL SYSTEM. TEMPS RIGHT ALONG LAKE SUPERIOR WILL LIKELY BE COOL ON SATURDAY (GENERALLY IN THE 50S) IN A LIGHT NRLY FLOW BUT FARTHER INLAND OVER THE INTERIOR WEST HALF LOWER TO MID 60S CAN BE EXPECTED UNDER PREVALENT SUNSHINE. SAT NIGHT...MODELS SHOW THE NEXT SW FLOW SHORTWAVE RIPPLING THROUGH THE UPPER LAKES. WAA ASSOC WITH THIS SHORTWAVE WILL BRING ANOTHER ROUND OF SCT SHRA TO THE AREA. MODELS MORE UNCERTAIN ON EVOLVING PATTERN DETAILS FOR SUNDAY INTO NEXT WED AS A PACIFIC SHORTWAVE DIGS SE...DEEPENING MID-UPR LVL TROF OVER THE SW CONUS FOR EARLY NEXT WEEK. BOTH THE ECMWF AND GEM-NH SHOW A MORE AMPLIFIED MID-UPR LEVEL TROF DEVELOPING OVER THE ROCKIES/WRN PLAINS FOR EARLY NEXT WEEK ALLOWING FOR A SOUTHERLY FLOW OF GULF MOISTURE AHEAD OF THE ASSOC FRONTAL SYSTEM TO WORK ITS WAY NORTH INTO THE UPPER GREAT LAKES REGION. THE GFS ON THE OTHER HAND IS LESS AMPLIFIED AND MORE PROGRESSIVE WITH THIS FRONT MOVING IT THROUGH RATHER QUICKLY SUN NIGHT INTO EARLY MONDAY. DECIDED TO GO ALONG MORE WITH NCEP PREFERRED SLOWER/MORE AMPLIFIED ECMWF/GEM IDEA WHICH SHOULD YIELD MORE SHOWERS OVER THE UPPER GREAT LAKES...ESPECIALLY MONDAY INTO MONDAY NIGHT. ALSO INCLUDED A SLIGHT CHC FOR TSRA OVER MUCH OF THE CWA ON MON NIGHT AND FOR THE ERN PORTION OF CWA ON TUE AS ECMWF INDICATES NEG SHOWALTER INDICES IN WARM SECTOR AHEAD OF FRONTAL PASSAGE. MODELS SUGGEST DRIER AND COOLER CONDITIONS TUE NIGHT INTO WED IN THE WAKE OF THE COLD FRONT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 407 PM EDT WED MAY 7 2014 ALTHOUGH THERE WL BE PLENTY OF HI AND MID CLDS ARND INTO THIS EVNG...PERSISTENT DRY ESE FETCH WL MAINTAIN VFR WX AT ALL 3 TAF SITES THRU AT LEAST SUNSET. BUT THE ARRIVAL OF MORE SHRA AND POSSIBLY A TS BY LATE EVNG AS WELL AS AN APRCHG WARM FNT/LOWERING INVRN/INCRSGLY MOIST AIRMASS TAPPED BY THE SE FLOW...EXPECT MVFR CONDITIONS TO DVLP LATE TNGT AT SAW AND CMX...WHERE THIS FLOW WL UPSLOPE. DOWNSLOPE NATURE OF THE WIND AT IWD SHOULD MAINTAIN VFR CONDITIONS THERE. SOME MARGINAL LLWS MAY IMPACT ALL 3 SITES WITH THE STRENGTHENING/LOWERING FRONTAL INVRN...ESPECIALLY AT CMX WHERE THE LLVL WINDS ABV THE MORE STABLE NEAR SFC LYR WL BE STRONGER. MORE LLVL MOISTENING AHEAD OF APRCHG SFC WARM FNT WL CAUSE CIGS TO DROP INTO THE IFR RANGE AT CMX AND SAW AND TO MVFR AT IWD ON THU MRNG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 407 PM EDT WED MAY 7 2014 EXPECT ENE WINDS UP TO 25 KTS TO VEER TO THE SE THRU THU AS LO PRES IN THE PLAINS APPROACHES THE AREA. THE STRONGEST WINDS ARE MOST LIKELY OVER THE W HALF OF LAKE SUPERIOR...WHERE THE TERRAIN WILL FUNNEL AND ENHANCE THE WINDS. SINCE THE LOW LEVEL AIR IS DRIER THAN EARLIER EXPECTED...TENDED TO SLOW DOWN THE ARRIVAL OF FOG AND CUT BACK ON THE COVERAGE. BUT AS MORE HUMID AIR MOVES IN LATER IN THE DAY AND THU NIGHT WITH A WIND SHIFT TO THE S AHEAD OF THE LO MOVING THRU MN...THE FOG SHOULD BECOME WIDESPREAD AND PERHAPS LOCALLY DENSE. THE LO WILL CONTINUE NE TOWARD JAMES BAY ON FRIDAY AND DRAG A TRAILING COLD FRONT ACROSS LAKE SUPERIOR DURING THE DAY...SHIFTING WINDS TO THE W. A HI PRES RIDGE WILL MOVE OVER THE LAKE ON FRI NIGHT AND REMAIN INTO SATURDAY...LEADING TO LIGHT WINDS. AS THE HI SHIFTS TO THE E AND ANOTHER DISTURBANCE APPROACHES FROM THE NW AND THEN PASSES ON MON...THE LLVL WINDS WILL VEER TO THE SSW AHEAD OF THE DISTURBANCE AND THEN THE TO NW FOLLOWING ITS PASSAGE EARLY MON. && .HYDROLOGY... ISSUED AT 449 PM EDT WED MAY 7 2014 WITH THE RECENT DRIER AND COOLER WEATHER...RIVER AND STREAM LEVELS HAVE SLOWLY COME DOWN OVER THE LAST 24 HOURS...ALTHOUGH THE STURGEON RIVER NEAR CHASSELL REMAINS CLOSE TO BANKFULL. WET WEATHER WILL RETURN TONIGHT INTO FRIDAY. MOST OF THE RAIN LOOKS TO FALL OVER THE STURGEON RIVER BASIN THURSDAY EVENING. ADDING TO THIS WILL BE A FEW INCHES OF SNOW WATER EQUIVALENT SHOWN FROM NOHRSC MODEL FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /WARMER FCST TEMPS FOR THE REST OF THE WEEK/ IMPACT DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS WILL AFFECT THE AREA TONIGHT INTO EARLY FRIDAY. RAINFALL AMOUNTS WILL LIKELY EXCEED A HALF OF AN INCH FOR MOST OF UPPER MICHIGAN...AND LOCALIZED AMOUNTS OVER AN INCH SHOULD OCCUR WHERE THUNDERSTORMS TRACK. THIS WILL KEEP THE RIVER LEVELS HIGH INTO EARLY NEXT WEEK. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...VOSS AVIATION...KC MARINE...KC HYDROLOGY...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 PM EDT WED MAY 7 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 407 PM EDT WED MAY 7 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW FAIRLY HI AMPLITUDE RDG BLDG FM THE SE CONUS INTO THE UPR LKS DOWNSTREAM OF A DEEP TROF IN THE ROCKIES. THERE ARE TWO CLOSED LOWS EMBEDDED IN THE TROF. ONE LO IS CENTERED OVER SASKATCHEWAN AND THE OVER THE DESERT SW. THE LO OVER THE DESERT SW WL HAVE THE MOST IMPACT ON UPR MI WX. WARM FNT TO THE E OF ASSOCIATED LO PRES IN THE CENTRAL PLAINS IS EXTENDING E THRU IOWA TOWARD THE LOWER LKS...WITH H85 FNT MOVING N INTO SRN MN/WI. A PAIR OF ELEVATED CONVECTIVE CLUSTERS THAT MOVED ENEWD WELL N OF THE WARM FNT IMPACTED MAINLY THE SCENTRAL COUNTIES THIS MRNG/EARLY AFTN...BUT LINGERING DRY AIR BEST DEPICTED ON THE 12Z APX RAOB AND HIER STABILITY THAT IS PRESENT FARTHER TO THE N PER LATEST SPC MESOANALYSIS LIMITED THE N PUSH OF THESE SHRA/TS INTO THE CWA. ABSENCE OF DYNAMIC FORCING OTHER THAN SOME GENERAL WAD/ ISENTROPIC ASCENT UNDER BLDG UPR RDG SO FAR TO THE NE OF MAIN FORCING MECHANISM CLOSER TO THE DESERT SW UPR LO IS RESULTING IN MAINLY DRY WX THIS AFTN...WITH MAINLY JUST THICKER HI CLDS IMPACTING AREAS AWAY FM THE SCENTRAL. MAIN FCST CONCERNS THRU THU INVOLVE POPS/ELEVATED TS CHCS AND INTENSITY TO THE N OF APRCHG SFC LO/ATTENDANT WARM FNT AS WELL AS POTENTIAL FOR FOG DVLPMNT. TNGT...UPR LO OVER THE DESERT SW IF FCST TO MOVE TO THE NE AND REACH THE WCENTRAL PLAINS BY 12Z THU. AS THE SFC LO SHIFTS SLOWLY TO THE NE AS WELL...ATTENDANT SFC WARM FNT IS FCST TO MOVE ONLY SLOWLY TO THE N INTO SCNTRL WI...BUT THE H85 FNT IS PROGGED TO LIFT MORE QUICKLY N THRU THE CWA. THE MOST APPRECIABLE DEEP LYR QVECTOR CNVGC/ UPR DVCG THAT IS NOW SUPPORTING MORE NMRS SHRA/SOME TS OVER THE NRN PLAINS INTO WRN MN IS FCST TO SWING INTO THE AREA FM THE W THIS EVNG AND IMPACT MAINLY THE NW PORTION OF THE CWA BEFORE EXITING TO THE NE LATER. AT LEAST SCT SHRA/SOME TS WL LIKELY SHIFT FARTHER TO THE ESE PARALLEL TO THE APRCHG H85 WARM FNT IN LINE WITH FCST CORFIDI VECTORS AND TOWARD STEEPER H7-5 LAPSE RATES. SINCE THE CONVECTION WL BE ELEVATED...PWAT WL BE APRCHG 200 PCT OF NORMAL AS WARMER/MOISTER AIR WITH H85 DEWPTS UP TO 12C FOLLOWING THE WARM FNT...AND FCST SDNGS IN THE MORE SATURATED AIRMASS SHOW THIN SKINNY CAPE...SUSPECT HEAVY RA WL BE THE MAIN THREAT. BUT SOME HAIL MAY FALL OVER THE STRONGER CELLS MAINLY NEAR THE SRN END OF THE SHRA AREA...WHERE FCST SDNGS SHOW STEEPER MID LVL LAPSE RATES /ALBEIT WITH A BIT MORE OF A CAP/ AND H85-3 WIND SHEAR IN THE ELEVATED UNSTABLE LYR IS AOA 40-50 KTS. THIS CAPPING WL BECOME MORE PRONOUNCED LATER FOLLOWING THE H85 WARM FROPA AND TEND TO DIMINISH POPS FM THE SW. AS THE LLVLS TO THE N OF INCRSGLY SHALLOW WARM FNT INVRN MOISTEN...EXPECT SOME FOG TO DVLP LATE...MAINLY WHERE THE EXPECTED ESE NEAR SFC FLOW UPSLOPES OFF LK MI. BUT TENDED TO CUT BACK ON THE FOG FCST TO ACCOUNT FOR STILL VERY DRY LLVLS. WITH INCRSG MSTR AND THE APRCH OF THE WARM FNT... EXPECT LTL DIURNAL TEMP FALL. THU...AS SHRTWV LIFTS TO THE NE AND INTO THE NRN PLAINS BY 00Z FRI...SFC LO IS FCST TO MOVE INTO SW MN BY 00Z FRI...WITH SFC WARM FNT TO THE E ARPCHG THE WI BORDER LATE. EXPECT PLENTY OF LO CLD TO THE N OF INCRSGLY SHALLOW WARM FNTL INVRN WITH SOME FOG AS WELL IN AREAS THAT EXPERIENCE UPSLOPE FLOW WITH THE LLVL SE WIND TO THE N OF THE FNT. BEST CHC FOR MORE NMRS SHRA/TS WL BE IN THE MRNG OVER THE NE HALF BEFORE CAPPING BEHIND H85 WARM FROPA/AREA OF DEEP LYR FORCING SHIFT TO THE NE AND GIVE WAY TO LARGER SCALE QVECTOR DVGC/ STRENGTHENING OF CAPPING INVRN. PREFER THE 12Z REGIONAL CNDN MODEL HANDLING OF THE POPS SHIFTED A BIT TO THE NE TOWARD THE LARGER SCALE FORCING AND AWAY FM LIKELY CAP. BEST CHC FOR SOME SUNSHINE WL BE OVER THE W IN THE AFTN WITH DOWNSLOPE SE WIND UNDER MID LVL CAPPING/ DRYING. HI TEMPS WL AT LEAST APRCH 70 IN THIS AREA. LINE OF SHRA/TS FED BY THIS HEATING AND CLOSER APRCH OF THE LO MAY MOVE INTO THE FAR W LATE IN THE DAY. THE CURRENT SPC OUTLOOK INDICATES FAR WRN UPR MI IS UNDER THE SLGT RISK FOR SVR STORMS. WITH SFC-6KM BULK SHEAR VALUES APRCHG 40-50KTS TOWARD 00Z IN THIS AREA AT THE TIME THE LINE OF CVNCTN MIGHT BE ARRIVING LATE IN THE DAY AHEAD OF THE SHARPER DEEP LYR QVECTOR CNVGC AND FCST MUCAPE AOA 1000J/KG...STRONGER STORMS WL BE PSBL IF SFC BASED PARCELS CAN BREAK THRU THE CAP. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 449 AM EDT WED MAY 7 2014 NAM SHOWS A 500 MB RIDGE OVER THE UPPER GREAT LAKES 12Z THU WITH A TROUGH OVER THE ROCKIES 12Z THU AND THIS TROUGH HEADS EAST INTO THE NORTHERN PLAINS ON THU AND INTO THE UPPER GREAT LAKES ON FRI. NAM BRINGS IN SOME ISENTROPIC LIFT AND MOISTURE ON I290K-I305K SURFACES ON THU WITH THE LIFT MOVING OUT OF THE AREA THU NIGHT. NAM ALSO BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE ON THU THAT LASTS INTO FRI MORNING BEFORE DEPARTING. GFS SHOWS ABOUT THE SAME THING. BASICALLY...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. TRYING TO FIGURE OUT THE CONVECTION IS TOUGH AND BROADBRUSHED IT FOR THE MOST PART WITH SCATTERED TO NUMEROUS POPS IN FOR THU. THU NIGHT LOOKS TO BE THE BEST CHANCE FOR PCPN AS THE WARM FRONT MOVES THROUGH AND WENT CATEGORICAL OVER THE WEST. HAVE A DRY SLOT MOVING THROUGH ON FRIDAY WITH DIMINISHING POPS. DID NOT MAKE TOO MANY CHANGES TO THE TEMPERATURES OVERALL. STILL LOOKS LIKE FOG IS A GOOD BET ESPECIALLY THU NIGHT ACROSS THE AREA. IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE WESTERN U.S. WITH A TROUGH OVER THE UPPER GREAT LAKES 12Z SAT. THE TROUGH IN THE WESTERN U.S. DIGS INTO THE ROCKIES 12Z SUN WITH A SHORTWAVE MOVING INTO THE UPPER GREAT LAKES. THIS TROUGH DIGS FURTHER INTO THE ROCKIES 12Z MON AND INTO THE PLAINS 12Z TUE. WHAT THIS WILL MEAN FOR THE AREA IS THE WEATHER WILL REMAIN UNSETTLED THROUGH THE PERIOD WITH THE ONLY DRY PERIOD LOOKING LIKE IT WILL BE SATURDAY. OTHERWISE...THERE WILL BE SLIGHT CHANCE TO CHANCE POPS IN FOR THE REST OF THE PERIOD. TEMPERATURES WILL REMAIN BELOW NORMAL FOR THIS FORECAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 407 PM EDT WED MAY 7 2014 ALTHOUGH THERE WL BE PLENTY OF HI AND MID CLDS ARND INTO THIS EVNG...PERSISTENT DRY ESE FETCH WL MAINTAIN VFR WX AT ALL 3 TAF SITES THRU AT LEAST SUNSET. BUT THE ARRIVAL OF MORE SHRA AND POSSIBLY A TS BY LATE EVNG AS WELL AS AN APRCHG WARM FNT/LOWERING INVRN/INCRSGLY MOIST AIRMASS TAPPED BY THE SE FLOW...EXPECT MVFR CONDITIONS TO DVLP LATE TNGT AT SAW AND CMX...WHERE THIS FLOW WL UPSLOPE. DOWNSLOPE NATURE OF THE WIND AT IWD SHOULD MAINTAIN VFR CONDITIONS THERE. SOME MARGINAL LLWS MAY IMPACT ALL 3 SITES WITH THE STRENGTHENING/LOWERING FRONTAL INVRN...ESPECIALLY AT CMX WHERE THE LLVL WINDS ABV THE MORE STABLE NEAR SFC LYR WL BE STRONGER. MORE LLVL MOISTENING AHEAD OF APRCHG SFC WARM FNT WL CAUSE CIGS TO DROP INTO THE IFR RANGE AT CMX AND SAW AND TO MVFR AT IWD ON THU MRNG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 407 PM EDT WED MAY 7 2014 EXPECT ENE WINDS UP TO 25 KTS TO VEER TO THE SE THRU THU AS LO PRES IN THE PLAINS APPROACHES THE AREA. THE STRONGEST WINDS ARE MOST LIKELY OVER THE W HALF OF LAKE SUPERIOR...WHERE THE TERRAIN WILL FUNNEL AND ENHANCE THE WINDS. SINCE THE LOW LEVEL AIR IS DRIER THAN EARLIER EXPECTED...TENDED TO SLOW DOWN THE ARRIVAL OF FOG AND CUT BACK ON THE COVERAGE. BUT AS MORE HUMID AIR MOVES IN LATER IN THE DAY AND THU NIGHT WITH A WIND SHIFT TO THE S AHEAD OF THE LO MOVING THRU MN...THE FOG SHOULD BECOME WIDESPREAD AND PERHAPS LOCALLY DENSE. THE LO WILL CONTINUE NE TOWARD JAMES BAY ON FRIDAY AND DRAG A TRAILING COLD FRONT ACROSS LAKE SUPERIOR DURING THE DAY...SHIFTING WINDS TO THE W. A HI PRES RIDGE WILL MOVE OVER THE LAKE ON FRI NIGHT AND REMAIN INTO SATURDAY...LEADING TO LIGHT WINDS. AS THE HI SHIFTS TO THE E AND ANOTHER DISTURBANCE APPROACHES FROM THE NW AND THEN PASSES ON MON...THE LLVL WINDS WILL VEER TO THE SSW AHEAD OF THE DISTURBANCE AND THEN THE TO NW FOLLOWING ITS PASSAGE EARLY MON. && .HYDROLOGY... ISSUED AT 449 AM EDT WED MAY 7 2014 STREAMS AND RIVERS WILL CONTINUE TO EXPERIENCE HIGHER LEVELS. LOCATIONS STILL NEAR OR ABOVE BANKFULL AT THIS TIME INCLUDE THE STURGEON RIVER IN HOUGHTON AND BARAGA COUNTIES. WET WEATHER WILL RETURN TONIGHT THROUGH FRIDAY EVENING. MOST OF THE RAIN LOOKS TO FALL OVER THE STURGEON RIVER BASIN THURSDAY EVENING. ADDING TO THIS WILL BE THE FEW INCHES OF SNOW WATER EQUIVALENT BEING SHOWN FROM NOHRSC SET UP FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /GIVEN WARMER FCST TEMPS FOR THE REST OF THE WEEK/ IMPACTS DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS WILL AFFECT THE AREA TONIGHT THROUGH FRIDAY NIGHT. RAINFALL AMOUNTS WILL LIKELY EXCEED A HALF OF AN INCH FOR MOST OF UPPER MICHIGAN...AND LOCALIZED AMOUNTS OVER AN INCH SHOULD OCCUR WHERE THUNDERSTORMS TRACK. THIS WILL KEEP THE RIVER LEVELS HIGH INTO EARLY NEXT WEEK. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...07 AVIATION...KC MARINE...KC HYDROLOGY...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
416 AM EDT WED MAY 7 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 322 PM EDT TUE MAY 6 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW BLDG UPR RDG/SFC HI PRES OVER THE UPR LKS BTWN TROF IN FAR ERN CANADA AND A PAIR OF CLOSED LOWS IN SPLIT FLOW ACRS THE W...ONE OVER ALBERTA AND THE OTHER DIGGING INTO THE DESERT SW. 12Z GRB/APX/MPX RAOBS INDICATE A DRY...STABLE AIRMASS IS IN PLACE...WITH PWAT AS LO AS 0.25 INCH AT APX. BUT THERE ARE PLENTY OF MID/HI CLDS ASSOCIATED WITH WAD/ ISENTROPIC ASCENT IN THE SW FLOW ALF BTWN THE HI OVER THE UPR LKS AND LOWER HGTS/MSLP TO THE W ASSOCIATED WITH THE WRN TROFFING. THERE IS A BAND OF THICKER MID LVL CLDS MOVING ENEWD THRU NE MN/WRN LK SUP AND TOWARD THE WRN LAND CWA ASSOCIATED WITH SHARPER ISENTROPIC ASCENT BEST SHOWN ON THE 300-305K SFCS...OR ABOUT H6-7...WELL TO THE NE OF DVLPG SFC-H85 WARM FNT IN THE CENTRAL PLAINS. BUT ADVECTION OF DRIER AIR IN THE LLVLS WITH STEADY ESE WINDS ON THE WRN FLANK OF THE SFC HI IS PREVENTING ANY PCPN FM REACHING THE GROUND E OF FAR WRN LK SUP. MAIN FCST CONCERN IN THE SHORTER TERM FOCUS ON PCPN CHCS ASSOCIATED WITH LARGER SCALE WAD/ISENTROPIC ASCENT TO THE NE OF WARM FNT NOW IN THE CENTRAL PLAINS. THIS AFTN/TNGT...ALTHOUGH HI CLDS WL SPILL OVER THE ENTIRE CWA THIS AFTN...BAND OF THICKER MID CLDS IS FCST TO IMPACT MAINLY THE NW PORTIONS OF THE CWA THIS AFTN BEFORE SHIFTING TO THE NE AFT SUNSET. THE LLVLS SHOULD REMAIN SUFFICIENTLY DRY TO KEEP PCPN FM REACHING THE SFC EVEN WHERE THE CLDS ARE THICKEST. THE PERIOD FM 00Z-06Z SHOULD BE DRY DESPITE CONSIDERABLE HI CLDS. WITH AN INCRSG H85 SW LLJ/THETA E ADVCTN/DEEP LYR QVECTOR CNVGC TNGT...MORE NMRS SHRA/TS ARE LIKELY TO DVLP AHEAD OF THE WARM FNT MOVING SLOWLY TO THE NE TOWARD SRN MN/WI BY 12Z. BUT SINCE THE SHARPER DEEP LYR QVECTOR CNVGC AND UPR DVGC ARE FCST TO REMAIN S OF UPR MI CLOSER TO THE WARM FNT...CORFIDI VECTORS FCST TO BE WNW IN WI TO THE N OF THE H85 WARM FNT WHICH WOULD RESULT IN MOST NMRS SHRA/TS REMAINING TO THE S AND ROBBING MSTR FOR PCPN FARTHER N...AND DRY AIR IS FCST TO LINGER IN THE SFC-H7 LYR WITHIN PERSISTENT ESE LLVL TRAJECTORIES...SUSPECT THE 12Z GFS IS TOO AGGRESSIVE TO LIFT PCPN INTO MUCH OF UPR MI BY 12Z WED. WL TREND THE FCST CLOSER TO THE DRIER 12Z NAM/REGIONAL CNDN MODELS. THIS GUIDANCE RESTRICTS QPF TO AREAS NEAR THE WI BORDER AND BAND OF SHARPER H85 FGEN. WL FCST HIER CHC POPS OVER SRN MENOMINEE COUNTY BUT GO WITH A DRY FCST FOR THE NE CWA. WED...SFC WARM FNT NEAR THE SRN MN/WI BORDER AND H85 WARM FNT INTO CENTRAL WI IS FCST TO REMAIN NEARLY STNRY THRU 00Z THU WELL TO THE NE OF DEEP TROF LINGERING IN THE DESERT SW. WELL TO THE NE OF THIS MAIN FORCING MECHANISM...12Z MODELS INDICATE DEEP LYR QVECTOR DVGC/SOME UPR CNVGC WL DOMINATE THRU MUCH OF THE AFTN UNDER INCRSGLY AMPLIFIED UPR RDG/HGT RISES TO THE N OF THE WARM FNT AND DIMINISHING DEEP LYR QVECTOR CNVGC THAT WL SUPPORT THE MAIN AREA OF SHRA/TS TO THE S AND SHIFT MAINLY TO THE E INTO THE LOWER LKS PARALLEL TO THE WARM FNT. SO SUSPECT THE MORE NMRS SHRA WL EXIT THE FAR SCENTRAL EARLY IN THE DAY AND LEAVE JUST ISOLD-SCT SHRA NEAR THE WI BORDER MOST OF THE DAY. INCLUDED MENTION OF SOME ELEVATED TS OVER THE FAR SCENTRAL LATER IN THE DAY TO ACCOUNT FOR AREA OF FCST LOWER SSI SHOWN BY THE MORE STABLE GFS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 441 PM EDT TUE MAY 6 2014 WHEN...WHERE...AND HOW MUCH PRECIPITATION WILL FALL ALONG WITH THE THUNDERSTORM POTENTIAL WILL BE THE MAIN CONCERNS IN THIS LONG TERM PERIOD. THE SLIGHT RISK TS POTENTIAL FROM SPC IS ALONG THE WI BORDER FOR THE WEDNESDAY NIGHT PERIOD. ANOTHER CONCERN WITH THE WARMER AIR WILL BE FOG...WHICH IS STILL FCST TUESDAY NIGHT THROUGH FRIDAY...PARTICULARLY ACROSS LAKE SUPERIOR AND LAKE MI. THE 500MB LOW CURRENTLY ALONG THE ALBERTA AND SASKATCHEWAN BORDER AND TROUGH EXTENDING ACROSS NV AND S CA THIS AFTERNOON WILL EVER SO SLOWLY PROGRESS E...STRETCHING FROM SASKATCHEWAN THROUGH THE 4-CORNERS REGION BY 06Z THURSDAY...AS THE HIGH AMPLITUDE RIDGE CONTINUES TO BUILD ACROSS THE UPPER GREAT LAKES /WITH THE APEX OVER MAINLY CENTRAL AND E UPPER MI/. WENT WITH HIGH CHANCE TO LIKELY POPS FOR THE W HALF OF UPPER MI WEDNESDAY NIGHT...SO DESPITE THE SE WINDS...TEMPERATURES SHOULD BE ABLE TO COOL INTO THE LOW TO MID 40S. THE WARM FRONT LOOKS TO CROSS INTO S WI AROUND 00Z THURSDAY...WITH SEVERAL DISTURBANCES EJECTING NE INTO THE AREA TO KEEP CHANCE TO LIKELY POPS GOING THROUGH THURSDAY. THE WARMEST DAY OVER THE W HALF /PENDING RAIN SHOWER/ LOOKS TO BE THURSDAY AS 850MB TEMPS RISE TO A CWA AVG OF 18C. CURRENTLY FCSTING HIGHS IN THE MID TO UPPER 60S AS THE SFC LOW TRACKS ACROSS S MN AND EXTENDING UP THROUGH W LAKE SUPERIOR. JUST HOW FAR N THE WARM FRONT CAN PUSH ACROSS THE REGION WILL BE A CONCERN TS WISE. AT THIS POINT IT LOOKS LIKE THE WARM FRONT MAY HOOK UP THROUGH SW UPPER MI AND NEAR THE WI BORDER AT 12Z THURSDAY...BEFORE THE SFC LOW AND ASSOCIATED COLD FRONT CATCH UP TO IT AS THE LOW SHIFTS OVER E MN/NW WI AND THE W HALF OF UPPER MI BY 06Z FRIDAY. EXPECT THE LOW TO N OF LAKE SUPERIOR ACROSS ONTARIO BY MID DAY FRIDAY...DRAGGING THE INITIAL COLD FRONT E OF UPPER MI. THE SECONDARY FRONT MAY BRING SOME WRAP AROUND MOISTURE INTO THE W HALF OF THE CWA FOR THE REMAINDER OF FRIDAY...AS WINDS BECOME MORE W-NW. 850MB TEMPS SHOULD FALL TO AROUND 2C BY SATURDAY MORNING AS PW VALUES FALL TO AROUND 0.3IN...OR 45-60 PERCENT OF NORMAL. CURRENTLY HAVE UPPER 30S FCST FOR THE W THIRD OF THE CWA...BUT WOULD NOT BE SURPRISED IF IT ENDS UP BEING A BIT LOWER. CONTINUED THE TREND OF LOWERING DEW POINTS ON SATURDAY...AS DRY HIGH PRESSURE TEMPORARILY BUILDS ACROSS THE UPPER GREAT LAKES. THE NEXT LOW /PICKED UP MUCH BETTER CONSISTENCY WISE OFF THE 12Z GFS AND ECMWF/ LOOKS TO BE OVER S CANADA AND MN AT 12Z SUNDAY. LOOK FOR THE RETURN OF RAIN SHOWERS. KEPT ANY MENTION OF TS TO THE SW AT THIS TIME. PRECIP LOOKS TO CONTINUE INTO MONDAY...AS LOW PRESSURE LINGERS ACROSS THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 107 AM EDT WED MAY 7 2014 ALTHOUGH SFC HIGH PRES RIDGE FROM NRN ONTARIO TO THE LWR LAKES WILL DRIFT E...DRIER E TO SE NEAR SFC FLOW EMANATING FROM THE RIDGE SHOULD WORK TO MAINTAIN VFR CONDITIONS AT KIWD/KCMX/KSAW THRU THIS FCST PERIOD. GRADUAL INCREASE IN MOISTURE/INSTABILITY ABOVE THE SHALLOW DRIER AIR WILL PROBABLY LEAD TO SOME SCT SHRA LIFTING INTO UPPER MI AT TIMES DESPITE WARM FRONT WELL S OF THE AREA. AT THIS POINT... THERE IS NOT MUCH CONFIDENCE IN PINNING DOWN BEST TIME PERIODS FOR PCPN. BEST CHC MAY BE AT KIWD LATER IN THE NIGHT AND THEN AGAIN THIS EVENING...SO VCSH WAS MENTIONED THERE. LLWS WAS INCLUDED OVERNIGHT AT KIWD/KSAW (LATEST KMQT RADAR VAD WIND PROFILE SHOWS SE WIND AROUND 30KT AT 500FT AGL). && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 415 AM EDT WED MAY 7 2014 LAKE SUPERIOR WILL INCREASINGLY COME UNDER THE INFLUENCE OF AN AREA OF LOW PRESSURE CURRENTLY FORMING OVER WESTERN KANSAS OVER THE NEXT TWO DAYS. EXPECT GENERAL EASTERLY FLOW OVER THE LAKE THROUGH THURSDAY...WITH A TREND MORE TO THE NORTHEAST OVER WESTERN HALF AND THE SOUTHEAST OVER THE EAST HALF. THIS FLOW WILL MAINLY PRODUCE WINDS UP TO 25KTS DURING THAT TIMEFRAME...WITH A FEW HIGHER GUSTS OVER FAR WESTERN LAKE SUPERIOR THROUGH TONIGHT WHERE THERE IS FAVORABLE FUNNELLING. AS THE LOW LIFTS ACROSS WESTERN LAKE SUPERIOR ON THURSDAY NIGHT AND EARLY FRIDAY MORNING...WINDS OVER THE EASTERN 2/3RD WILL SHIFT TO THE SOUTH AND REMAIN UP TO 25KTS. ALTHOUGH THERE WILL BE STRONGER WINDS ALOFT...EXPECT THE MARINE LAYER TO KEEP THE WINDS AT THE SURFACE LOWER. THE LOW WILL CONTINUE NORTHEAST TO JAMES BAY ON FRIDAY AND DRAG A TRAILING COLD FRONT ACROSS LAKE SUPERIOR ON FRIDAY...SHIFTING WINDS TO THE WEST. A HIGH PRESSURE RIDGE WILL MOVE OVER THE LAKE ON FRIDAY NIGHT AND REMAIN INTO SATURDAY...LEADING TO LIGHT WINDS. && .HYDROLOGY... ISSUED AT 309 PM EDT TUE MAY 6 2014 STREAMS AND RIVERS WILL CONTINUE TO EXPERIENCE HIGHER LEVELS. LOCATIONS STILL NEAR OR ABOVE BANKFULL AT THIS TIME INCLUDE THE STURGEON RIVER IN HOUGHTON AND BARAGA COUNTIES AND THE TAHQUAMENON RIVER NEAR PARADISE. WHILE WET WEATHER WILL RETURN LATE TONIGHT THROUGH FRIDAY EVENING...RAINFALL SHOULD AROUND A TENTH OF AN INCH OR LESS THROUGH THE DAY WEDNESDAY. AT THE CURRENT TIME MOST OF THE RAIN LOOKS TO FALL OVER THE STURGEON RIVER BASIN THURSDAY EVENING. ADDING TO THIS WILL BE THE FEW INCHES OF SNOW WATER EQUIVALENT BEING SHOWN FROM NOHRSC SET UP FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /GIVEN WARMER FCST TEMPS FOR THE REST OF THE WEEK/ IMPACTS DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND. FLOWS WILL LIKELY INCREASE OUT OF THE PRICKETT DAM OVER THE NEXT DAY OR TWO...WHICH WILL LEAD TO CONTINUED HIGHER LEVELS ON THE STURGEON RIVER IN HOUGHTON/BARAGA COUNTIES. WITH THE ALREADY HIGH LEVELS...ALSM4/CLLM4 MAY REACH FLOOD STAGE. BACK TO THE WET WEATHER EXPECTED THROUGH FRIDAY EVENING...SEVERAL ROUNDS OF SHOWERS AND POTENTIALLY THUNDERSTORMS WILL AFFECT THE AREA DURING THE SECOND HALF OF THE WORK WEEK. RAINFALL AMOUNTS WILL LIKELY EXCEED A HALF OF AN INCH FOR MOST OF UPPER MICHIGAN...AND LOCALIZED AMOUNTS OVER AN INCH SHOULD OCCUR WHERE THUNDERSTORMS TRACK. THIS WILL KEEP THE RIVER LEVELS HIGH INTO NEXT WEEKEND. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...SRF HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
112 AM EDT WED MAY 7 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 322 PM EDT TUE MAY 6 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW BLDG UPR RDG/SFC HI PRES OVER THE UPR LKS BTWN TROF IN FAR ERN CANADA AND A PAIR OF CLOSED LOWS IN SPLIT FLOW ACRS THE W...ONE OVER ALBERTA AND THE OTHER DIGGING INTO THE DESERT SW. 12Z GRB/APX/MPX RAOBS INDICATE A DRY...STABLE AIRMASS IS IN PLACE...WITH PWAT AS LO AS 0.25 INCH AT APX. BUT THERE ARE PLENTY OF MID/HI CLDS ASSOCIATED WITH WAD/ ISENTROPIC ASCENT IN THE SW FLOW ALF BTWN THE HI OVER THE UPR LKS AND LOWER HGTS/MSLP TO THE W ASSOCIATED WITH THE WRN TROFFING. THERE IS A BAND OF THICKER MID LVL CLDS MOVING ENEWD THRU NE MN/WRN LK SUP AND TOWARD THE WRN LAND CWA ASSOCIATED WITH SHARPER ISENTROPIC ASCENT BEST SHOWN ON THE 300-305K SFCS...OR ABOUT H6-7...WELL TO THE NE OF DVLPG SFC-H85 WARM FNT IN THE CENTRAL PLAINS. BUT ADVECTION OF DRIER AIR IN THE LLVLS WITH STEADY ESE WINDS ON THE WRN FLANK OF THE SFC HI IS PREVENTING ANY PCPN FM REACHING THE GROUND E OF FAR WRN LK SUP. MAIN FCST CONCERN IN THE SHORTER TERM FOCUS ON PCPN CHCS ASSOCIATED WITH LARGER SCALE WAD/ISENTROPIC ASCENT TO THE NE OF WARM FNT NOW IN THE CENTRAL PLAINS. THIS AFTN/TNGT...ALTHOUGH HI CLDS WL SPILL OVER THE ENTIRE CWA THIS AFTN...BAND OF THICKER MID CLDS IS FCST TO IMPACT MAINLY THE NW PORTIONS OF THE CWA THIS AFTN BEFORE SHIFTING TO THE NE AFT SUNSET. THE LLVLS SHOULD REMAIN SUFFICIENTLY DRY TO KEEP PCPN FM REACHING THE SFC EVEN WHERE THE CLDS ARE THICKEST. THE PERIOD FM 00Z-06Z SHOULD BE DRY DESPITE CONSIDERABLE HI CLDS. WITH AN INCRSG H85 SW LLJ/THETA E ADVCTN/DEEP LYR QVECTOR CNVGC TNGT...MORE NMRS SHRA/TS ARE LIKELY TO DVLP AHEAD OF THE WARM FNT MOVING SLOWLY TO THE NE TOWARD SRN MN/WI BY 12Z. BUT SINCE THE SHARPER DEEP LYR QVECTOR CNVGC AND UPR DVGC ARE FCST TO REMAIN S OF UPR MI CLOSER TO THE WARM FNT...CORFIDI VECTORS FCST TO BE WNW IN WI TO THE N OF THE H85 WARM FNT WHICH WOULD RESULT IN MOST NMRS SHRA/TS REMAINING TO THE S AND ROBBING MSTR FOR PCPN FARTHER N...AND DRY AIR IS FCST TO LINGER IN THE SFC-H7 LYR WITHIN PERSISTENT ESE LLVL TRAJECTORIES...SUSPECT THE 12Z GFS IS TOO AGGRESSIVE TO LIFT PCPN INTO MUCH OF UPR MI BY 12Z WED. WL TREND THE FCST CLOSER TO THE DRIER 12Z NAM/REGIONAL CNDN MODELS. THIS GUIDANCE RESTRICTS QPF TO AREAS NEAR THE WI BORDER AND BAND OF SHARPER H85 FGEN. WL FCST HIER CHC POPS OVER SRN MENOMINEE COUNTY BUT GO WITH A DRY FCST FOR THE NE CWA. WED...SFC WARM FNT NEAR THE SRN MN/WI BORDER AND H85 WARM FNT INTO CENTRAL WI IS FCST TO REMAIN NEARLY STNRY THRU 00Z THU WELL TO THE NE OF DEEP TROF LINGERING IN THE DESERT SW. WELL TO THE NE OF THIS MAIN FORCING MECHANISM...12Z MODELS INDICATE DEEP LYR QVECTOR DVGC/SOME UPR CNVGC WL DOMINATE THRU MUCH OF THE AFTN UNDER INCRSGLY AMPLIFIED UPR RDG/HGT RISES TO THE N OF THE WARM FNT AND DIMINISHING DEEP LYR QVECTOR CNVGC THAT WL SUPPORT THE MAIN AREA OF SHRA/TS TO THE S AND SHIFT MAINLY TO THE E INTO THE LOWER LKS PARALLEL TO THE WARM FNT. SO SUSPECT THE MORE NMRS SHRA WL EXIT THE FAR SCENTRAL EARLY IN THE DAY AND LEAVE JUST ISOLD-SCT SHRA NEAR THE WI BORDER MOST OF THE DAY. INCLUDED MENTION OF SOME ELEVATED TS OVER THE FAR SCENTRAL LATER IN THE DAY TO ACCOUNT FOR AREA OF FCST LOWER SSI SHOWN BY THE MORE STABLE GFS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 441 PM EDT TUE MAY 6 2014 WHEN...WHERE...AND HOW MUCH PRECIPITATION WILL FALL ALONG WITH THE THUNDERSTORM POTENTIAL WILL BE THE MAIN CONCERNS IN THIS LONG TERM PERIOD. THE SLIGHT RISK TS POTENTIAL FROM SPC IS ALONG THE WI BORDER FOR THE WEDNESDAY NIGHT PERIOD. ANOTHER CONCERN WITH THE WARMER AIR WILL BE FOG...WHICH IS STILL FCST TUESDAY NIGHT THROUGH FRIDAY...PARTICULARLY ACROSS LAKE SUPERIOR AND LAKE MI. THE 500MB LOW CURRENTLY ALONG THE ALBERTA AND SASKATCHEWAN BORDER AND TROUGH EXTENDING ACROSS NV AND S CA THIS AFTERNOON WILL EVER SO SLOWLY PROGRESS E...STRETCHING FROM SASKATCHEWAN THROUGH THE 4-CORNERS REGION BY 06Z THURSDAY...AS THE HIGH AMPLITUDE RIDGE CONTINUES TO BUILD ACROSS THE UPPER GREAT LAKES /WITH THE APEX OVER MAINLY CENTRAL AND E UPPER MI/. WENT WITH HIGH CHANCE TO LIKELY POPS FOR THE W HALF OF UPPER MI WEDNESDAY NIGHT...SO DESPITE THE SE WINDS...TEMPERATURES SHOULD BE ABLE TO COOL INTO THE LOW TO MID 40S. THE WARM FRONT LOOKS TO CROSS INTO S WI AROUND 00Z THURSDAY...WITH SEVERAL DISTURBANCES EJECTING NE INTO THE AREA TO KEEP CHANCE TO LIKELY POPS GOING THROUGH THURSDAY. THE WARMEST DAY OVER THE W HALF /PENDING RAIN SHOWER/ LOOKS TO BE THURSDAY AS 850MB TEMPS RISE TO A CWA AVG OF 18C. CURRENTLY FCSTING HIGHS IN THE MID TO UPPER 60S AS THE SFC LOW TRACKS ACROSS S MN AND EXTENDING UP THROUGH W LAKE SUPERIOR. JUST HOW FAR N THE WARM FRONT CAN PUSH ACROSS THE REGION WILL BE A CONCERN TS WISE. AT THIS POINT IT LOOKS LIKE THE WARM FRONT MAY HOOK UP THROUGH SW UPPER MI AND NEAR THE WI BORDER AT 12Z THURSDAY...BEFORE THE SFC LOW AND ASSOCIATED COLD FRONT CATCH UP TO IT AS THE LOW SHIFTS OVER E MN/NW WI AND THE W HALF OF UPPER MI BY 06Z FRIDAY. EXPECT THE LOW TO N OF LAKE SUPERIOR ACROSS ONTARIO BY MID DAY FRIDAY...DRAGGING THE INITIAL COLD FRONT E OF UPPER MI. THE SECONDARY FRONT MAY BRING SOME WRAP AROUND MOISTURE INTO THE W HALF OF THE CWA FOR THE REMAINDER OF FRIDAY...AS WINDS BECOME MORE W-NW. 850MB TEMPS SHOULD FALL TO AROUND 2C BY SATURDAY MORNING AS PW VALUES FALL TO AROUND 0.3IN...OR 45-60 PERCENT OF NORMAL. CURRENTLY HAVE UPPER 30S FCST FOR THE W THIRD OF THE CWA...BUT WOULD NOT BE SURPRISED IF IT ENDS UP BEING A BIT LOWER. CONTINUED THE TREND OF LOWERING DEW POINTS ON SATURDAY...AS DRY HIGH PRESSURE TEMPORARILY BUILDS ACROSS THE UPPER GREAT LAKES. THE NEXT LOW /PICKED UP MUCH BETTER CONSISTENCY WISE OFF THE 12Z GFS AND ECMWF/ LOOKS TO BE OVER S CANADA AND MN AT 12Z SUNDAY. LOOK FOR THE RETURN OF RAIN SHOWERS. KEPT ANY MENTION OF TS TO THE SW AT THIS TIME. PRECIP LOOKS TO CONTINUE INTO MONDAY...AS LOW PRESSURE LINGERS ACROSS THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 107 AM EDT WED MAY 7 2014 ALTHOUGH SFC HIGH PRES RIDGE FROM NRN ONTARIO TO THE LWR LAKES WILL DRIFT E...DRIER E TO SE NEAR SFC FLOW EMANATING FROM THE RIDGE SHOULD WORK TO MAINTAIN VFR CONDITIONS AT KIWD/KCMX/KSAW THRU THIS FCST PERIOD. GRADUAL INCREASE IN MOISTURE/INSTABILITY ABOVE THE SHALLOW DRIER AIR WILL PROBABLY LEAD TO SOME SCT SHRA LIFTING INTO UPPER MI AT TIMES DESPITE WARM FRONT WELL S OF THE AREA. AT THIS POINT... THERE IS NOT MUCH CONFIDENCE IN PINNING DOWN BEST TIME PERIODS FOR PCPN. BEST CHC MAY BE AT KIWD LATER IN THE NIGHT AND THEN AGAIN THIS EVENING...SO VCSH WAS MENTIONED THERE. LLWS WAS INCLUDED OVERNIGHT AT KIWD/KSAW (LATEST KMQT RADAR VAD WIND PROFILE SHOWS SE WIND AROUND 30KT AT 500FT AGL). && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 322 PM EDT TUE MAY 6 2014 AS THE PRES GRADIENT TIGHTENS OVER LAKE SUPERIOR ON THE SW FLANK OF HI PRES RETREATING THRU ONTARIO AND IN ADVANCE OF LO PRES/ATTENDANT WARM FRONT LIFTING NE FROM THE PLAINS...EXPECT SLOWLY VEERING NE TO SE WINDS UP TO 15-25 KTS TO DOMINATE INTO THU. AS HIGHER DEW POINTS ARRIVE ON WED NIGHT/THU...FOG WILL DEVELOP OVER THE COLDER/ICE COVERED LAKE WATERS. WINDS WILL THEN VEER FROM THE SE TO THE W ON THU NIGHT THRU SAT AS THE LOW PRES TRACKS OVER FAR WESTERN LAKE SUPERIOR AND INTO NW ONTARIO. THE ARRIVAL OF DRIER AIR IN THE WAKE OF THIS LOW WILL CAUSE THE FOG TO DISSIPATE FRI NIGHT. WINDS WILL THEN SHIFT TO THE E ON SUN AS THE HI PRES TRAILING THE DEPARTING LO MOVES TO THE E. NO GALES SEEN IN THIS FORECAST PERIOD. && .HYDROLOGY... ISSUED AT 309 PM EDT TUE MAY 6 2014 STREAMS AND RIVERS WILL CONTINUE TO EXPERIENCE HIGHER LEVELS. LOCATIONS STILL NEAR OR ABOVE BANKFULL AT THIS TIME INCLUDE THE STURGEON RIVER IN HOUGHTON AND BARAGA COUNTIES AND THE TAHQUAMENON RIVER NEAR PARADISE. WHILE WET WEATHER WILL RETURN LATE TONIGHT THROUGH FRIDAY EVENING...RAINFALL SHOULD AROUND A TENTH OF AN INCH OR LESS THROUGH THE DAY WEDNESDAY. AT THE CURRENT TIME MOST OF THE RAIN LOOKS TO FALL OVER THE STURGEON RIVER BASIN THURSDAY EVENING. ADDING TO THIS WILL BE THE FEW INCHES OF SNOW WATER EQUIVALENT BEING SHOWN FROM NOHRSC SET UP FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /GIVEN WARMER FCST TEMPS FOR THE REST OF THE WEEK/ IMPACTS DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND. FLOWS WILL LIKELY INCREASE OUT OF THE PRICKETT DAM OVER THE NEXT DAY OR TWO...WHICH WILL LEAD TO CONTINUED HIGHER LEVELS ON THE STURGEON RIVER IN HOUGHTON/BARAGA COUNTIES. WITH THE ALREADY HIGH LEVELS...ALSM4/CLLM4 MAY REACH FLOOD STAGE. BACK TO THE WET WEATHER EXPECTED THROUGH FRIDAY EVENING...SEVERAL ROUNDS OF SHOWERS AND POTENTIALLY THUNDERSTORMS WILL AFFECT THE AREA DURING THE SECOND HALF OF THE WORK WEEK. RAINFALL AMOUNTS WILL LIKELY EXCEED A HALF OF AN INCH FOR MOST OF UPPER MICHIGAN...AND LOCALIZED AMOUNTS OVER AN INCH SHOULD OCCUR WHERE THUNDERSTORMS TRACK. THIS WILL KEEP THE RIVER LEVELS HIGH INTO NEXT WEEKEND. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
146 PM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 434 AM CDT WED MAY 7 2014 SURFACE WARM FRONT THIS MORNING WAS JUST CROSSING THE BORDER FROM MO INTO IA AND IS ASSOCIATED WITH A 995 MB SFC LOW IN THE VICINITY OF CO/KS/NEB. THERE ARE A COUPLE OF BANDS OF STORMS OUT THERE THIS MORNING. ONE EXTENDS FROM CLEVELAND BACK TO GREEN BAY THAT YOU CAN FOLLOW BACK TO SHOWERS IN THE DULUTH AREA AND ASSOCIATED WITH THE ARRIVAL OF THE ELEVATED CAPE. AT THE NOSE OF THE LLJ AND EDGE OF THE CAPPING INVERSION /WHERE H7 TEMPS EXCEED +9C/ YOU WILL FIND A BROKEN LINE OF STORMS ALONG THE MN/IA. MPXWRF AND SPCWRF PRETTY MUCH NAILED THESE STORMS...SO FOLLOWED THE TREND OF THESE MODELS FOR WORKING HIGHER POPS SOUTH OF A MANKATO/RED WING/CHIP FALLS LINE THROUGH THE MORNING. GIVEN THE RAPS DEPICTION OF THE LLJ VEERING MORE EASTERLY THROUGH THE MORNING WITH LITTLE DEVELOPMENT NORTH...IT MAKES SENSE THAT THESE STORMS WILL NOT BUILD MUCH FARTHER NORTH OF THEIR CURRENT LATITUDE AND WILL INSTEAD HEAD MORE OR LESS DOWN I-90 INTO CENTRAL WI WITH THE LLJ. NOT EXPECTING MUCH SEVERE POTENTIAL OUT OF THESE...BUT WITH EFFECTIVE SHEAR UP NEAR 30 KTS AND CAPE BETWEEN -10C AND -30C /HAIL CAPE/ UP AROUND 500 J/KG...WE WILL LIKELY CONTINUE TO SEE THE OCCASIONAL STORM PUT OUT HAIL THAT GETS UP IN THE 1 INCH TERRITORY OR SLIGHTLY LARGER. BEHIND THIS MORNING ACTIVITY...H7 TEMPS WILL PUSH UP TO BETWEEN 8 AND 10C...WITH A VERY DRY PLUME OF AIR COMING IN IN THE H7-H5 LEVEL AS WELL. THIS WILL LIKELY KEEP THE MPX AREA CAPPED AND DRY MUCH OF THE DAY AS WE WATCH THE WARM FRONT LIFT NORTH ACROSS IOWA. BY PEAK HEATING...THIS WARM FRONT LOOKS TO BE UP NEAR I-90. WARM SECTOR COMING UP WITH THIS FRONT IS THE SAME AIRMASS THAT HAS SPENT THE LAST THREE DAYS BREAKING RECORD HIGHS ACROSS TX/OK/KS...SO IT WILL BE WARM TO SAY THE LEAST...WITH HIGHS IN THE 90S LIKELY CLEAR UP TO THE I-80 CORRIDOR. THIS WARM FRONT STILL MAKES FOR A DIFFICULT FORECAST AS OVERCAST CONDITIONS TO THE NORTH OF THE FRONT WILL HOLD HIGHS BACK IN THE 50S/60S...WHILE SOUTH OF THE BOUNDARY IT WILL BE FEELING LIKE SUMMER. CONTINUED TO FAVOR THIS FORECAST TOWARD THE ECMWF...WHICH HAS MID 80S ALONG I-90 THAT FALL BACK TO THE UPPER 50S/LOWER 60S NORTH OF I-94. WE WILL HAVE TO WATCH THOSE TEMPS THOUGH. THERE IS VIRTUALLY NO CLOUD COVER ACROSS IOWA RIGHT NOW...AND IF THIS TREND CONTINUES OVER US THIS AFTERNOON...THEN SOMETHING MUCH CLOSER TO WHAT THE RAP HAS BEEN SHOWING ALL MORNING IS POSSIBLE...WHICH IS LOWER 90S COMING UP AS FAR NORTH AS MANKATO/REDWOOD FALLS...WITH HIGHS CLOSER TO 80 IN THE CITIES...WITH EVEN THE COLDER AREAS AROUND LADYSMITH PUSHING 70. MAIN QUESTION FOR THIS EVENING/TONIGHT IS WHEN DOES THE CAP BREAK. ONCE IT DOES...IT IS LOOKING LIKE A VERY ACTIVE NIGHT ACROSS THE MPX CWA. THROUGH THE AFTERNOON...ANY ACTIVITY LOOKS TO REMAIN TO THE NW OF THE CAP...WHICH WOULD KEEP THE BULK OF THE ACTIVITY TODAY OUT FROM CENTRAL SODAK INTO NW MN. EVENTUALLY...A STRENGTHENING LLJ AND THE APPROACH OF THE MAIN UPPER TROUGH WILL START TO ERODE THE CAP. GENERALLY FOLLOWED THE IDEA OF THE SPCWRF AND THE NMM/ARW WITH ACTIVITY TAKING OFF BETWEEN 2Z AND 4Z. GIVEN THE DEGREE OF INSTABILITY EXPECTED AND EFFECTIVE SHEARS UP AROUND 50 KTS...IT IS VERY LIKELY THAT THESE STORMS WILL BE ABLE TO PRODUCE LARGE HAIL...SO THE DAY1 SLIGHT RISK IS MORE THAN WARRANTED. ALTHOUGH NO CONVECTION IS CURRENTLY ANTICIPATED IN THE AFTERNOON...IF WE WERE TO SEE SOMETHING GO IT WOULD HAVE A HIGH LIKELIHOOD OF BEING SEVERE...WITH A TORNADO THREAT IF IT IS CLOSE TO THE WARM FRONT. HOWEVER...THE WARM/DRY LAYER NOTED EARLIER AROUND H7 WILL MOST LIKELY KEEP ANYTHING FROM GOING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 434 AM CDT WED MAY 7 2014 THE EXTENDED PERIOD WILL BE AN ACTIVE ONE WITH ONLY ONE DRY PERIOD FORECAST AND THAT IS FRIDAY NIGHT. THURSDAY IS THE DAY OF INTEREST. ALL INDICATIONS ARE FOR LOW PRESSURE OVER EASTERN NEBRASKA THURSDAY MORNING TO SLOWLY DEEPEN WHILE MOVING INTO SOUTHWEST MINNESOTA DURING THE AFTERNOON AND INTO CENTRAL MINNESOTA DURING THE EVENING. CONVECTION IS ANTICIPATED TO BE ONGOING THURSDAY MORNING ACROSS CENTRAL MN AND WEST CENTRAL WI. THIS WILL MOVE NORTHEAST EARLY ON ALLOWING FOR THE DESTABILIZATION TO COMMENCE. PROJECTIONS FOR THE AFTERNOON AND EVENING HOURS ARE FOR 0-1KM SHEAR TO BE IN THE 25-35 KNOT RANGE AHEAD OF THE LOW AND COLD FRONT WITH 0-6KM SHEAR IN THE 40-50 KNOT RANGE. EASTERN MN AND WESTERN WI ARE ALSO IN A FAVORABLE COUPLED JET ALOFT WITH 100 KNOT RIGHT ENTRANCE REGION OVER NORTHERN MN WHILE A 100+ KNOT JET SURGES INTO EASTERN IA DURING THE AFTERNOON. THE DIFFERENTIAL DIVERGENCE IS QUITE STRONG BY EVENING ACROSS THE TWIN CITIES. ALSO...VARIOUS SOLUTIONS ARE POINTING TO 0-3KM CAPE REACHING 100-150 J/KG BY LATE IN THE AFTERNOON...AGAIN CLOSE TO THE TWIN CITIES. HENCE...A SEVERE AFTERNOON AND EVENING IS LOOKING MORE AND MORE LIKELY WITH ALL FORMS OF SEVERE WEATHER POSSIBLE INCLUDING A FEW TORNADOES. THE SEVERE THREAT SHOULD BE OVER BY MIDNIGHT ACROSS WESTERN WI AS THE ATTENDANT COLD FRONT MOVES THROUGH. HIGHS ON THURSDAY HAVE POTENTIAL TO RUN INTO THE 80S FROM THE TWIN CITIES ON SOUTH AND SOUTHWEST. BLENDED GUIDANCE KEPT HIGHS IN THE UPPER 70S. A FEW SHOWERS MAY LINGER OVER NORTHERN AND EASTERN AREAS OF THE FA ON FRIDAY UNDER THE COLD UPPER TROUGH. AS MENTIONED EARLIER...FRIDAY NIGHT IS THE ONLY DRY PERIOD AS A WEAK RIDGE OF HIGH PRESSURE MOVES THROUGH. THE PATTERN STARTS TO BECOME MORE ACTIVE AGAIN ON SATURDAY AS NORTHERN AND SOUTHERN STREAM ENERGY BEGIN TO INFLUENCE THE WESTERN HALF OF THE CONUS. THIS DEVELOPS ANOTHER WAVE OF LOW PRESSURE TO OUR SOUTHWEST WITH SHOWER CHANCES INCREASING THROUGH THE WEEKEND AND EARLY NEXT WEEK. SOME SIGNIFICANT DIFFERENCES EXIST BETWEEN THE GFS AND EC BY EARLY NEXT WEEK ON THE LOCATION OF THE SURFACE LOW. THE GFS WOULD BE FLATTER AND FURTHER EAST WITH THE LOW WHILE THE EC IS MORE ROBUST WITH THE UPPER TROUGH AND SURFACE LOW. THIS WILL NEED TO BE WATCHED AS WE COULD BE CLOSE TO THE WARM SECTOR ALONG WITH A SEVERE WEATHER THREAT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1257 PM CDT WED MAY 7 2014 AT LEAST A COUPLE ROUNDS OF THUNDERSTORMS ARE EXPECTED OVER THE NEXT 24 HOURS. THE FIRST ROUND ARRIVES THIS EVENING AND SHOULD MAINLY AFFECT EASTERN MN AND WESTERN WI BETWEEN 01Z-06Z. THE MAIN THREAT WITH THE STORMS TONIGHT WILL BE LARGE. THE SECOND ROUND OF STORMS IS EXPECTED LATE IN THE MORING IN WESTERN MN AND DURING THE AFTERNOON IN EASTERN MN AND WESTERN WI. MVFR CEILINGS HAVE BEEN SLOW TO ADVANCE NORTH TODAY...AND IT ACTUALLY LOOKS LIKE THAT MOST OF THE 2000-3000FT CEILINGS WILL STAY IN FAR WESTERN MN. KMSP... NO AVIATION WEATHER CONCERNS FOR THE REMAINDER OF THE DAYLIGHT HOURS /INCLUDING THE EVENING PUSH/. WE EXPECTED THUNDERSTORMS IN EASTERN MN LATE THIS EVENING...BUT MOST OF THE ACTIVITY WILL OCCUR BETWEEN 02-04Z...WITH THE PRIMARY THREAT BEING LARGE HAIL. WE ARE MUCH LESS CONFIDENT IN HOW MUCH ACTIVITY WILL PERSIST OVERNIGHT AND INTO THE THURSDAY MORNING COMMUTE. MOST OF THE ACTIVITY SHOULD FOCUS ITSELF NORTH OF THE AIRPORT. THE SECOND ROUND HAS A BETTER CHANCE AT PRODUCING SEVERE WEATHER TOMORROW AFTERNOON. /OUTLOOK FOR KMSP/ THU NIGHT...MVFR CONDITIONS POSSIBLE WITH SHOWERS AND THUNDERSTORMS. WINDS S BECOMING W AT 10G20KTS. FRI...MVFR EARLY...THEN VFR. WINDS W AT 10G20KTS. SAT...VFR. WINDS S 5-10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
703 AM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 434 AM CDT WED MAY 7 2014 SURFACE WARM FRONT THIS MORNING WAS JUST CROSSING THE BORDER FROM MO INTO IA AND IS ASSOCIATED WITH A 995 MB SFC LOW IN THE VICINITY OF CO/KS/NEB. THERE ARE A COUPLE OF BANDS OF STORMS OUT THERE THIS MORNING. ONE EXTENDS FROM CLEVELAND BACK TO GREEN BAY THAT YOU CAN FOLLOW BACK TO SHOWERS IN THE DULUTH AREA AND ASSOCIATED WITH THE ARRIVAL OF THE ELEVATED CAPE. AT THE NOSE OF THE LLJ AND EDGE OF THE CAPPING INVERSION /WHERE H7 TEMPS EXCEED +9C/ YOU WILL FIND A BROKEN LINE OF STORMS ALONG THE MN/IA. MPXWRF AND SPCWRF PRETTY MUCH NAILED THESE STORMS...SO FOLLOWED THE TREND OF THESE MODELS FOR WORKING HIGHER POPS SOUTH OF A MANKATO/RED WING/CHIP FALLS LINE THROUGH THE MORNING. GIVEN THE RAPS DEPICTION OF THE LLJ VEERING MORE EASTERLY THROUGH THE MORNING WITH LITTLE DEVELOPMENT NORTH...IT MAKES SENSE THAT THESE STORMS WILL NOT BUILD MUCH FARTHER NORTH OF THEIR CURRENT LATITUDE AND WILL INSTEAD HEAD MORE OR LESS DOWN I-90 INTO CENTRAL WI WITH THE LLJ. NOT EXPECTING MUCH SEVERE POTENTIAL OUT OF THESE...BUT WITH EFFECTIVE SHEAR UP NEAR 30 KTS AND CAPE BETWEEN -10C AND -30C /HAIL CAPE/ UP AROUND 500 J/KG...WE WILL LIKELY CONTINUE TO SEE THE OCCASIONAL STORM PUT OUT HAIL THAT GETS UP IN THE 1 INCH TERRITORY OR SLIGHTLY LARGER. BEHIND THIS MORNING ACTIVITY...H7 TEMPS WILL PUSH UP TO BETWEEN 8 AND 10C...WITH A VERY DRY PLUME OF AIR COMING IN IN THE H7-H5 LEVEL AS WELL. THIS WILL LIKELY KEEP THE MPX AREA CAPPED AND DRY MUCH OF THE DAY AS WE WATCH THE WARM FRONT LIFT NORTH ACROSS IOWA. BY PEAK HEATING...THIS WARM FRONT LOOKS TO BE UP NEAR I-90. WARM SECTOR COMING UP WITH THIS FRONT IS THE SAME AIRMASS THAT HAS SPENT THE LAST THREE DAYS BREAKING RECORD HIGHS ACROSS TX/OK/KS...SO IT WILL BE WARM TO SAY THE LEAST...WITH HIGHS IN THE 90S LIKELY CLEAR UP TO THE I-80 CORRIDOR. THIS WARM FRONT STILL MAKES FOR A DIFFICULT FORECAST AS OVERCAST CONDITIONS TO THE NORTH OF THE FRONT WILL HOLD HIGHS BACK IN THE 50S/60S...WHILE SOUTH OF THE BOUNDARY IT WILL BE FEELING LIKE SUMMER. CONTINUED TO FAVOR THIS FORECAST TOWARD THE ECMWF...WHICH HAS MID 80S ALONG I-90 THAT FALL BACK TO THE UPPER 50S/LOWER 60S NORTH OF I-94. WE WILL HAVE TO WATCH THOSE TEMPS THOUGH. THERE IS VIRTUALLY NO CLOUD COVER ACROSS IOWA RIGHT NOW...AND IF THIS TREND CONTINUES OVER US THIS AFTERNOON...THEN SOMETHING MUCH CLOSER TO WHAT THE RAP HAS BEEN SHOWING ALL MORNING IS POSSIBLE...WHICH IS LOWER 90S COMING UP AS FAR NORTH AS MANKATO/REDWOOD FALLS...WITH HIGHS CLOSER TO 80 IN THE CITIES...WITH EVEN THE COLDER AREAS AROUND LADYSMITH PUSHING 70. MAIN QUESTION FOR THIS EVENING/TONIGHT IS WHEN DOES THE CAP BREAK. ONCE IT DOES...IT IS LOOKING LIKE A VERY ACTIVE NIGHT ACROSS THE MPX CWA. THROUGH THE AFTERNOON...ANY ACTIVITY LOOKS TO REMAIN TO THE NW OF THE CAP...WHICH WOULD KEEP THE BULK OF THE ACTIVITY TODAY OUT FROM CENTRAL SODAK INTO NW MN. EVENTUALLY...A STRENGTHENING LLJ AND THE APPROACH OF THE MAIN UPPER TROUGH WILL START TO ERODE THE CAP. GENERALLY FOLLOWED THE IDEA OF THE SPCWRF AND THE NMM/ARW WITH ACTIVITY TAKING OFF BETWEEN 2Z AND 4Z. GIVEN THE DEGREE OF INSTABILITY EXPECTED AND EFFECTIVE SHEARS UP AROUND 50 KTS...IT IS VERY LIKELY THAT THESE STORMS WILL BE ABLE TO PRODUCE LARGE HAIL...SO THE DAY1 SLIGHT RISK IS MORE THAN WARRANTED. ALTHOUGH NO CONVECTION IS CURRENTLY ANTICIPATED IN THE AFTERNOON...IF WE WERE TO SEE SOMETHING GO IT WOULD HAVE A HIGH LIKELIHOOD OF BEING SEVERE...WITH A TORNADO THREAT IF IT IS CLOSE TO THE WARM FRONT. HOWEVER...THE WARM/DRY LAYER NOTED EARLIER AROUND H7 WILL MOST LIKELY KEEP ANYTHING FROM GOING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 434 AM CDT WED MAY 7 2014 THE EXTENDED PERIOD WILL BE AN ACTIVE ONE WITH ONLY ONE DRY PERIOD FORECAST AND THAT IS FRIDAY NIGHT. THURSDAY IS THE DAY OF INTEREST. ALL INDICATIONS ARE FOR LOW PRESSURE OVER EASTERN NEBRASKA THURSDAY MORNING TO SLOWLY DEEPEN WHILE MOVING INTO SOUTHWEST MINNESOTA DURING THE AFTERNOON AND INTO CENTRAL MINNESOTA DURING THE EVENING. CONVECTION IS ANTICIPATED TO BE ONGOING THURSDAY MORNING ACROSS CENTRAL MN AND WEST CENTRAL WI. THIS WILL MOVE NORTHEAST EARLY ON ALLOWING FOR THE DESTABILIZATION TO COMMENCE. PROJECTIONS FOR THE AFTERNOON AND EVENING HOURS ARE FOR 0-1KM SHEAR TO BE IN THE 25-35 KNOT RANGE AHEAD OF THE LOW AND COLD FRONT WITH 0-6KM SHEAR IN THE 40-50 KNOT RANGE. EASTERN MN AND WESTERN WI ARE ALSO IN A FAVORABLE COUPLED JET ALOFT WITH 100 KNOT RIGHT ENTRANCE REGION OVER NORTHERN MN WHILE A 100+ KNOT JET SURGES INTO EASTERN IA DURING THE AFTERNOON. THE DIFFERENTIAL DIVERGENCE IS QUITE STRONG BY EVENING ACROSS THE TWIN CITIES. ALSO...VARIOUS SOLUTIONS ARE POINTING TO 0-3KM CAPE REACHING 100-150 J/KG BY LATE IN THE AFTERNOON...AGAIN CLOSE TO THE TWIN CITIES. HENCE...A SEVERE AFTERNOON AND EVENING IS LOOKING MORE AND MORE LIKELY WITH ALL FORMS OF SEVERE WEATHER POSSIBLE INCLUDING A FEW TORNADOES. THE SEVERE THREAT SHOULD BE OVER BY MIDNIGHT ACROSS WESTERN WI AS THE ATTENDANT COLD FRONT MOVES THROUGH. HIGHS ON THURSDAY HAVE POTENTIAL TO RUN INTO THE 80S FROM THE TWIN CITIES ON SOUTH AND SOUTHWEST. BLENDED GUIDANCE KEPT HIGHS IN THE UPPER 70S. A FEW SHOWERS MAY LINGER OVER NORTHERN AND EASTERN AREAS OF THE FA ON FRIDAY UNDER THE COLD UPPER TROUGH. AS MENTIONED EARLIER...FRIDAY NIGHT IS THE ONLY DRY PERIOD AS A WEAK RIDGE OF HIGH PRESSURE MOVES THROUGH. THE PATTERN STARTS TO BECOME MORE ACTIVE AGAIN ON SATURDAY AS NORTHERN AND SOUTHERN STREAM ENERGY BEGIN TO INFLUENCE THE WESTERN HALF OF THE CONUS. THIS DEVELOPS ANOTHER WAVE OF LOW PRESSURE TO OUR SOUTHWEST WITH SHOWER CHANCES INCREASING THROUGH THE WEEKEND AND EARLY NEXT WEEK. SOME SIGNIFICANT DIFFERENCES EXIST BETWEEN THE GFS AND EC BY EARLY NEXT WEEK ON THE LOCATION OF THE SURFACE LOW. THE GFS WOULD BE FLATTER AND FURTHER EAST WITH THE LOW WHILE THE EC IS MORE ROBUST WITH THE UPPER TROUGH AND SURFACE LOW. THIS WILL NEED TO BE WATCHED AS WE COULD BE CLOSE TO THE WARM SECTOR ALONG WITH A SEVERE WEATHER THREAT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 649 AM CDT WED MAY 7 2014 BIGGEST THING TO SAY FIRST IS THE GFSLAMP WAS IGNORED IN TERMS OF ITS CIG FORECAST. THE WARM FRONT IS MAKING ITS WAY NORTH ACROSS IOWA...HOWEVER THERE ARE VIRTUALLY NO CLOUDS BELOW 12K FEET IN IOWA...SO FIND IT HARD TO BELIEVE THE VERY PESSIMISTIC LAMP FORECASTS. INSTEAD CONTINUED TO FOLLOW THE IDEA OF THE NAM...WITH CIGS NOT REALLY LOWERING MUCH UNTIL A LOCATION GETS CLOSER TO THE WARM FRONT. AND EVEN THEN...THE HRRR/RAP SAY WE WILL NOT SEE MUCH IN THE WAY OF STRATUS ANYWAYS...SO CONTINUED THE TREND OF BACKING OFF ON THE MVFR MENTION. HI-RES MODELS CONTINUE TO SHOW TSRA DEVELOPING IN THE VCNTY OF RWF BETWEEN 00Z AND 03Z...THEN RAPIDLY EXPANDING ACROSS THE AREA AFTER 3Z AS THE WARM FRONT LIFTS NORTH. COULD BE SEVERAL HOURS OF SHRA/TSRA ACTIVITY FOR STC/AXN ONCE THINGS GO. THIS IS ALSO THE PERIOD WHEN LOWER CIGS WOULD BE MOST LIKELY...BUT EVEN THEN WE MAY STAY PREDOMINATELY VFR. KMSP...STORMS WILL STAY WELL SOUTH OF THE FIELD THIS MORNING...AND ATMOSPHERE WILL REMAIN CAPPED TO KEEP THE FIELD DRY UNTIL LIKELY BETWEEN 2Z AND 4Z. CONFIDENCE HIGH IN TSRA IMPACTING THE FIELD TONIGHT...BUT A BIT LOWER ON EXACT TIMING. DO FEEL WARM FRONT WILL HAVE LIFTED FAR ENOUGH THOUGH BY 12Z THU THAT MSP SHOULD BE DONE WITH THE OVERNIGHT ACTIVITY BY THEN. AS FOR CIGS...BEGINNING TO LOSE CONFIDENCE THAT WE WILL SEE MUCH IN THE WAY OF RESTRICTIONS AT ALL OUTSIDE OF PRECIP...SO CONTINUED TO TREND TOWARD KEEPING CIGS HIGHER. /OUTLOOK FOR KMSP/ THU...VFR EARLY WITH IFR/TSRA LIKELY IN THE AFTERNOON. SOME STORMS MAY BE SEVERE. WINDS SE BECOMING S AT 10G20KTS. FRI...MVFR EARLY...THEN VFR. WINDS W AT 10G20KTS. SAT...VFR. WINDS S 5-10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
434 AM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 434 AM CDT WED MAY 7 2014 SURFACE WARM FRONT THIS MORNING WAS JUST CROSSING THE BORDER FROM MO INTO IA AND IS ASSOCIATED WITH A 995 MB SFC LOW IN THE VICINITY OF CO/KS/NEB. THERE ARE A COUPLE OF BANDS OF STORMS OUT THERE THIS MORNING. ONE EXTENDS FROM CLEVELAND BACK TO GREEN BAY THAT YOU CAN FOLLOW BACK TO SHOWERS IN THE DULUTH AREA AND ASSOCIATED WITH THE ARRIVAL OF THE ELEVATED CAPE. AT THE NOSE OF THE LLJ AND EDGE OF THE CAPPING INVERSION /WHERE H7 TEMPS EXCEED +9C/ YOU WILL FIND A BROKEN LINE OF STORMS ALONG THE MN/IA. MPXWRF AND SPCWRF PRETTY MUCH NAILED THESE STORMS...SO FOLLOWED THE TREND OF THESE MODELS FOR WORKING HIGHER POPS SOUTH OF A MANKATO/RED WING/CHIP FALLS LINE THROUGH THE MORNING. GIVEN THE RAPS DEPICTION OF THE LLJ VEERING MORE EASTERLY THROUGH THE MORNING WITH LITTLE DEVELOPMENT NORTH...IT MAKES SENSE THAT THESE STORMS WILL NOT BUILD MUCH FARTHER NORTH OF THEIR CURRENT LATITUDE AND WILL INSTEAD HEAD MORE OR LESS DOWN I-90 INTO CENTRAL WI WITH THE LLJ. NOT EXPECTING MUCH SEVERE POTENTIAL OUT OF THESE...BUT WITH EFFECTIVE SHEAR UP NEAR 30 KTS AND CAPE BETWEEN -10C AND -30C /HAIL CAPE/ UP AROUND 500 J/KG...WE WILL LIKELY CONTINUE TO SEE THE OCCASIONAL STORM PUT OUT HAIL THAT GETS UP IN THE 1 INCH TERRITORY OR SLIGHTLY LARGER. BEHIND THIS MORNING ACTIVITY...H7 TEMPS WILL PUSH UP TO BETWEEN 8 AND 10C...WITH A VERY DRY PLUME OF AIR COMING IN IN THE H7-H5 LEVEL AS WELL. THIS WILL LIKELY KEEP THE MPX AREA CAPPED AND DRY MUCH OF THE DAY AS WE WATCH THE WARM FRONT LIFT NORTH ACROSS IOWA. BY PEAK HEATING...THIS WARM FRONT LOOKS TO BE UP NEAR I-90. WARM SECTOR COMING UP WITH THIS FRONT IS THE SAME AIRMASS THAT HAS SPENT THE LAST THREE DAYS BREAKING RECORD HIGHS ACROSS TX/OK/KS...SO IT WILL BE WARM TO SAY THE LEAST...WITH HIGHS IN THE 90S LIKELY CLEAR UP TO THE I-80 CORRIDOR. THIS WARM FRONT STILL MAKES FOR A DIFFICULT FORECAST AS OVERCAST CONDITIONS TO THE NORTH OF THE FRONT WILL HOLD HIGHS BACK IN THE 50S/60S...WHILE SOUTH OF THE BOUNDARY IT WILL BE FEELING LIKE SUMMER. CONTINUED TO FAVOR THIS FORECAST TOWARD THE ECMWF...WHICH HAS MID 80S ALONG I-90 THAT FALL BACK TO THE UPPER 50S/LOWER 60S NORTH OF I-94. WE WILL HAVE TO WATCH THOSE TEMPS THOUGH. THERE IS VIRTUALLY NO CLOUD COVER ACROSS IOWA RIGHT NOW...AND IF THIS TREND CONTINUES OVER US THIS AFTERNOON...THEN SOMETHING MUCH CLOSER TO WHAT THE RAP HAS BEEN SHOWING ALL MORNING IS POSSIBLE...WHICH IS LOWER 90S COMING UP AS FAR NORTH AS MANKATO/REDWOOD FALLS...WITH HIGHS CLOSER TO 80 IN THE CITIES...WITH EVEN THE COLDER AREAS AROUND LADYSMITH PUSHING 70. MAIN QUESTION FOR THIS EVENING/TONIGHT IS WHEN DOES THE CAP BREAK. ONCE IT DOES...IT IS LOOKING LIKE A VERY ACTIVE NIGHT ACROSS THE MPX CWA. THROUGH THE AFTERNOON...ANY ACTIVITY LOOKS TO REMAIN TO THE NW OF THE CAP...WHICH WOULD KEEP THE BULK OF THE ACTIVITY TODAY OUT FROM CENTRAL SODAK INTO NW MN. EVENTUALLY...A STRENGTHENING LLJ AND THE APPROACH OF THE MAIN UPPER TROUGH WILL START TO ERODE THE CAP. GENERALLY FOLLOWED THE IDEA OF THE SPCWRF AND THE NMM/ARW WITH ACTIVITY TAKING OFF BETWEEN 2Z AND 4Z. GIVEN THE DEGREE OF INSTABILITY EXPECTED AND EFFECTIVE SHEARS UP AROUND 50 KTS...IT IS VERY LIKELY THAT THESE STORMS WILL BE ABLE TO PRODUCE LARGE HAIL...SO THE DAY1 SLIGHT RISK IS MORE THAN WARRANTED. ALTHOUGH NO CONVECTION IS CURRENTLY ANTICIPATED IN THE AFTERNOON...IF WE WERE TO SEE SOMETHING GO IT WOULD HAVE A HIGH LIKELIHOOD OF BEING SEVERE...WITH A TORNADO THREAT IF IT IS CLOSE TO THE WARM FRONT. HOWEVER...THE WARM/DRY LAYER NOTED EARLIER AROUND H7 WILL MOST LIKELY KEEP ANYTHING FROM GOING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 434 AM CDT WED MAY 7 2014 THE EXTENDED PERIOD WILL BE AN ACTIVE ONE WITH ONLY ONE DRY PERIOD FORECAST AND THAT IS FRIDAY NIGHT. THURSDAY IS THE DAY OF INTEREST. ALL INDICATIONS ARE FOR LOW PRESSURE OVER EASTERN NEBRASKA THURSDAY MORNING TO SLOWLY DEEPEN WHILE MOVING INTO SOUTHWEST MINNESOTA DURING THE AFTERNOON AND INTO CENTRAL MINNESOTA DURING THE EVENING. CONVECTION IS ANTICIPATED TO BE ONGOING THURSDAY MORNING ACROSS CENTRAL MN AND WEST CENTRAL WI. THIS WILL MOVE NORTHEAST EARLY ON ALLOWING FOR THE DESTABILIZATION TO COMMENCE. PROJECTIONS FOR THE AFTERNOON AND EVENING HOURS ARE FOR 0-1KM SHEAR TO BE IN THE 25-35 KNOT RANGE AHEAD OF THE LOW AND COLD FRONT WITH 0-6KM SHEAR IN THE 40-50 KNOT RANGE. EASTERN MN AND WESTERN WI ARE ALSO IN A FAVORABLE COUPLED JET ALOFT WITH 100 KNOT RIGHT ENTRANCE REGION OVER NORTHERN MN WHILE A 100+ KNOT JET SURGES INTO EASTERN IA DURING THE AFTERNOON. THE DIFFERENTIAL DIVERGENCE IS QUITE STRONG BY EVENING ACROSS THE TWIN CITIES. ALSO...VARIOUS SOLUTIONS ARE POINTING TO 0-3KM CAPE REACHING 100-150 J/KG BY LATE IN THE AFTERNOON...AGAIN CLOSE TO THE TWIN CITIES. HENCE...A SEVERE AFTERNOON AND EVENING IS LOOKING MORE AND MORE LIKELY WITH ALL FORMS OF SEVERE WEATHER POSSIBLE INCLUDING A FEW TORNADOES. THE SEVERE THREAT SHOULD BE OVER BY MIDNIGHT ACROSS WESTERN WI AS THE ATTENDANT COLD FRONT MOVES THROUGH. HIGHS ON THURSDAY HAVE POTENTIAL TO RUN INTO THE 80S FROM THE TWIN CITIES ON SOUTH AND SOUTHWEST. BLENDED GUIDANCE KEPT HIGHS IN THE UPPER 70S. A FEW SHOWERS MAY LINGER OVER NORTHERN AND EASTERN AREAS OF THE FA ON FRIDAY UNDER THE COLD UPPER TROUGH. AS MENTIONED EARLIER...FRIDAY NIGHT IS THE ONLY DRY PERIOD AS A WEAK RIDGE OF HIGH PRESSURE MOVES THROUGH. THE PATTERN STARTS TO BECOME MORE ACTIVE AGAIN ON SATURDAY AS NORTHERN AND SOUTHERN STREAM ENERGY BEGIN TO INFLUENCE THE WESTERN HALF OF THE CONUS. THIS DEVELOPS ANOTHER WAVE OF LOW PRESSURE TO OUR SOUTHWEST WITH SHOWER CHANCES INCREASING THROUGH THE WEEKEND AND EARLY NEXT WEEK. SOME SIGNIFICANT DIFFERENCES EXIST BETWEEN THE GFS AND EC BY EARLY NEXT WEEK ON THE LOCATION OF THE SURFACE LOW. THE GFS WOULD BE FLATTER AND FURTHER EAST WITH THE LOW WHILE THE EC IS MORE ROBUST WITH THE UPPER TROUGH AND SURFACE LOW. THIS WILL NEED TO BE WATCHED AS WE COULD BE CLOSE TO THE WARM SECTOR ALONG WITH A SEVERE WEATHER THREAT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1247 AM CDT WED MAY 7 2014 AT ABOUT 530Z...TSRA STARTED BUBBLING UP TO THE SOUTH OF FSD...RIGHT ABOUT WHEN/WHERE THE HRRR AND MPXWRF HAD THEM FORMING. FOLLOWED THOSE MODELS FOR TIMING WHAT SHOULD BE A LINE OF TSRA TO NEAR THE EAU AREA BETWEEN 12Z AND 14Z. THIS ACTIVITY LOOKS TO REMAIN SOUTH OF RWF/MSP...BUT LOOKS TO GET CLOSE ENOUGH TO WARRANT A CONTINUED MENTION OF A VCSH. ALSO NEEDED TO SLOW DOWN THE ARRIVAL OF ANY SHRA AS WELL AND ALSO SIGNIFICANTLY SLOWED DOWN THE ARRIVAL OF MVFR OR LOWER CIGS. FOLLOWED THE NAM/HRRR IDEA WITH CIGS REMAINING MORE AROUND 4K FT MUCH OF THE DAY UNTIL THE WARM FRONT GETS CLOSER TO EACH TERMINAL...WHICH IS WHEN A SIGNIFICANT DROP IN CIGS IS ANTICIPATED. WITH CIGS TO THE NORTH OF THE WARM FRONT ACROSS IA STILL UP BETWEEN 5K AND 7K FT...FOUND IT HARD TO BELIEVE THE GFSLAMP FOR HOW AGGRESSIVE IT IS WITH BRINGING IN THE LOWER CIGS. NOT EXPECTING ANY PRECIP ON WED...BUT FAVORED THE SPCWRF FOR HOW MORE WIDESPREAD TSRA ACTIVITY GOES DOWN AT THE END OF THE TAF PERIOD. KMSP...CONFIDENCE IS HIGH THAT TSRA TONIGHT/WED MORNING WILL REMAIN SOUTH OF THE FIELD...BUT MAY BE CLOSE ENOUGH TO IMPACT ANY DEPARTING/ARRIVING TRAFFIC. LESS CONFIDENCE IN CIG FORECAST AS THE APPROACH OF THE WARM FRONT COINCIDING WITH PEAK HEATING MAY MAKE IT TOUGH FOR MVFR CIGS TO DEVELOP EVEN AS EARLY AS 6Z TAF HAS IT. CONFIDENCE MUCH HIGHER IN TSRA IMPACTING THE FIELD WED NIGHT...THOUGH LESS CONFIDENCE ON TIMING. THE WARM FRONT LOOKS TO SURGE NORTH AFTER 00Z...WHICH SHOULD AID IN THE RAPID EXPANSION OF TSRA ACROSS MN. ONCE STORMS START...COULD BE A VERY LONG NIGHT FOR SEEING ACTIVITY IN THE AREA. /OUTLOOK FOR KMSP/ THU...VFR EARLY WITH IFR/TSRA LIKELY IN THE AFTERNOON. SOME STORMS MAY BE SEVERE. WINDS SE BECOMING S AT 10G20KTS. FRI...MVFR EARLY...THEN VFR. WINDS W AT 10G20KTS. SAT...VFR. WINDS S 5-10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
105 AM CDT WED MAY 7 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 249 PM CDT TUE MAY 6 2014 A DEFUSE WARM FRONT WAS LOCATED OVER NORTHERN MISSOURI AND NORTHERN KANSAS AT 3 PM WHICH WILL ADVANCE SLOWLY NORTHWARD TO THE I-80 CORRIDOR BY EARLY WEDNESDAY MORNING. THIS WILL NOT DO MUCH TO GENERATE STORMS. INSTEAD...THE MAIN FORCING MECHANISM FOR STORM DEVELOPMENT TONIGHT WILL BE STRONG WAA AT 850 MB...KICKED OFF BY A STRENGTHENING LLJ THIS EVENING. AS THE INVERSION AT 850 CONTINUES TO INCREASE...ELEVATED INSTABILITY WILL GROW ABOVE THIS LEVEL...BUT CAPPING AT THIS LEVEL WILL ALSO MAKE IT MORE DIFFICULT TO GENERATE STORMS AWAY FROM THE FORCING OF THE JET. THE BEST POTENTIAL FOR STORMS WILL BE ACROSS SOUTHERN MINNESOTA AND PORTIONS OF SOUTHWEST AND WEST CENTRAL WISCONSIN...MAINLY SOUTH OF A LINE FROM HUDSON TO LADYSMITH. SYNOPTIC MODELS SEEM TO HAVE A GOOD HANDLE ON THIS IN TERMS OF QPF PLACEMENT...BUT THE MOST RECENT RUN OF THE HOPWRF /15Z/ SHOWS STORMS INITIATING FURTHER NORTH INCLUDING THE REDWOOD FALLS...TWIN CITIES...AND NEW RICHMOND AREAS AROUND MIDNIGHT. THUS...ENOUGH UNCERTAINTY STILL EXISTS TO PREVENT US FROM REDUCING POPS TOO MUCH ACROSS EASTERN MINNESOTA AND NORTHWESTERN WISCONSIN. LIKELY OR CATEGORICAL POPS ARE STILL IN PLACE TO THE SOUTH. BROAD ISENTROPIC LIFT ACROSS THE UPPER MIDWEST WILL BRING THE REST OF THE AREA A SLIGHT CHANCE OF STORMS...INCLUDING WESTERN AND CENTRAL MINNESOTA. MODEST AMOUNTS OF SHEAR WILL KEEP SEVERE WEATHER CHANCES MARGINAL...HOWEVER A SEVERE STORM OR TWO ARE CERTAINLY POSSIBLE FROM SOUTH CENTRAL MN TO WEST CENTRAL WI GIVEN STEEPENING MID LEVEL LAPSE RATES. WEDNESDAY WILL BE MOSTLY DRY. WITHOUT THE LLJ...NOT MUCH FORCING WILL EXIST TO OVERCOME SIGNIFICANT CAPPING BETWEEN 700-800 MB. BEST POTENTIAL FOR DEVELOPMENT WILL BE ACROSS WESTERN MN WHERE A SURFACE LOW LIFTING NORTH MAY ERODE SOME OF THE STRONG CAPPING. THIS LOW WILL ALSO DRAG THE WARM FRONT FROM IOWA NORTHWARD INTO FAR SOUTHERN MINNESOTA DURING THE AFTERNOON. MODELS ARE ALL OVER THE PLACE IN TERMS OF PLACEMENT...AND THIS WILL PLAY A BIG ROLE IN HOW WARM LOCATIONS GET. SOUTH OF THE FRONT...LOW TO MID 80S WILL BE EASILY ATTAINABLE WITH EVEN 90S ACROSS EASTERN NEBRASKA AND IOWA...BUT NORTH WILL BE SOCKED IN CONSIDERABLE CLOUDS AND AN EASTERLY FLOW KEEPING TEMPS IN THE UPPER 50S AND 60S. GEM SEEMS A BIT TOO FAR NORTH WITH THE FRONT REACHING CENTRAL MN...WHEREAS THE GFS DOES NOT SEEM AGGRESSIVE ENOUGH KEEPING IT ACROSS NORTHERN IOWA. SPLIT THE DIFFERENCE FOR THE GRIDS...WHICH MATCHES BEST WITH THE NAM AND ECMWF BRINGING 80S UP TO THE I-90 CORRIDOR. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 249 PM CDT TUE MAY 6 2014 A STRONG STORM SYSTEM IS STILL FORECAST TO IMPACT THE AREA WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THERE REMAINS SOME MODEL DISAGREEMENTS IN TERMS OF OVERALL TRACK AND TIMING OF THE SFC LOW...AND THE STRENGTH OF A DRY SLOT TO AFFECT THE AREA. THEN THE LONGER RANGE MODELS SHOW ANOTHER POTENTIAL SYSTEM MOVING ACROSS THE AREA SAT NIGHT/SUN WITH HINTS AT ANOTHER STRONG STORM SYSTEM FOR THE BEGINNING OF NEXT WEEK. INTO WEDNESDAY NIGHT...THE STRENGTHENING LLJ WILL LEAD TO BETTER CHANCES FOR STORMS NORTH OF THE WARM FRONT. WE HAVE CONTINUED TO TREND POPS FROM AROUND 70% FOR CENTRAL MN TO JUST 30% DOWN TOWARD I-90. MID LEVEL FLOW IS FORECAST TO INTO TO NEAR 50 KTS/MUCAPE OVER 2000 J/KG AND MID LEVEL LAPSE RATES FROM 8-9C/KM...THERE WILL BE AMPLE OPPORTUNITY FOR THIS ACTIVITY TO BE SEVERE...WITH LARGE HAIL BEING THE MAIN THREAT GIVEN THE ELEVATED NATURE OF THE ACTIVITY NORTH OF THE WAR FRONT. FOR THURSDAY...THERE REMAINS SOME UNCERTAINTY WITH HOW THE EVENT WILL DEVELOP. PREVIOUS CONVECTION WILL HAVE SOME AFFECT ON OVERALL DEVELOPMENT EARLY IN THE PERIOD..AND HOW FAR NORTH THE WARM SECTOR WILL MOVE. THE GFS AND ECMWF HAVE COME INTO SOME AGREEMENT ON SLOWER MOVEMENT OF THE UPPER TROUGH AND THE MOVEMENT OF THE SURFACE LOW. THERE WILL LIKELY BE SOME SCATTERED CONVECTION OVER THE NORTHERN CWA EARLY THURSDAY. DEVELOPMENT WILL LIKELY INITIATE EARLY INTO THE SOUTHWEST...WITH LIKELY POPS AGAIN OVER MUCH OF THE AREA AFTER 15Z. CATEGORICAL POPS REMAIN OVER THE NORTH AND EAST PART OF THE CWA INTO THE AFTERNOON AS WELL...AS THE SURFACE LOW LIFTS NORTHEAST ACROSS THE CENTRAL CWA. THE GFS IS INDICATING SOME HIGH PROBABILITIES OF TORNADO DEVELOPMENT INTO CENTRAL AND EASTERN CWA INTO THE AFTERNOON. WE CERTAINLY HAVE ENOUGH INSTABILITY AND FORCING/110KT 30H JET MAX NOSING INTO EASTERN MN DURING THE AFTERNOON. THE 12Z ECMWF IS SLOWER WITH DEVELOPMENT INTO THE AFTERNOON BUT IT DEVELOPS EVEN A LARGER AREA OF HEAVY RAIN OVER THE CENTRAL AND EASTERN PORTIONS OF THE AREA. AT THE MOMENT...THE SLIGHT RISK FOR MUCH OF THE AREA IS WARRANTED....WITH HAIL AND STRONG WINDS A GOOD BET. CANT RULE OUT THE ISOLATED TORNADO HOWEVER. THE GFS AND ECMWF CONTINUE TO SHOW A WEAK WAVE LIFTING EAST OVER THE AREA SATURDAY NIGHT/SUNDAY TIME FRAME. THEN THEY DIVERGE HOWEVER ...WITH THE ECMWF MUCH SLOWER WITH THE WESTERN CONUS TROUGH...AND IT AFFECTS THIS REGION INTO EARLY NEXT WEEK. WILL HAVE TO HOLD ONTO SOME LOW CHANCE POPS DURING THIS PERIOD BECAUSE OF MODEL DISCREPANCIES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1247 AM CDT WED MAY 7 2014 AT ABOUT 530Z...TSRA STARTED BUBBLING UP TO THE SOUTH OF FSD...RIGHT ABOUT WHEN/WHERE THE HRRR AND MPXWRF HAD THEM FORMING. FOLLOWED THOSE MODELS FOR TIMING WHAT SHOULD BE A LINE OF TSRA TO NEAR THE EAU AREA BETWEEN 12Z AND 14Z. THIS ACTIVITY LOOKS TO REMAIN SOUTH OF RWF/MSP...BUT LOOKS TO GET CLOSE ENOUGH TO WARRANT A CONTINUED MENTION OF A VCSH. ALSO NEEDED TO SLOW DOWN THE ARRIVAL OF ANY SHRA AS WELL AND ALSO SIGNIFICANTLY SLOWED DOWN THE ARRIVAL OF MVFR OR LOWER CIGS. FOLLOWED THE NAM/HRRR IDEA WITH CIGS REMAINING MORE AROUND 4K FT MUCH OF THE DAY UNTIL THE WARM FRONT GETS CLOSER TO EACH TERMINAL...WHICH IS WHEN A SIGNIFICANT DROP IN CIGS IS ANTICIPATED. WITH CIGS TO THE NORTH OF THE WARM FRONT ACROSS IA STILL UP BETWEEN 5K AND 7K FT...FOUND IT HARD TO BELIEVE THE GFSLAMP FOR HOW AGGRESSIVE IT IS WITH BRINGING IN THE LOWER CIGS. NOT EXPECTING ANY PRECIP ON WED...BUT FAVORED THE SPCWRF FOR HOW MORE WIDESPREAD TSRA ACTIVITY GOES DOWN AT THE END OF THE TAF PERIOD. KMSP...CONFIDENCE IS HIGH THAT TSRA TONIGHT/WED MORNING WILL REMAIN SOUTH OF THE FIELD...BUT MAY BE CLOSE ENOUGH TO IMPACT ANY DEPARTING/ARRIVING TRAFFIC. LESS CONFIDENCE IN CIG FORECAST AS THE APPROACH OF THE WARM FRONT COINCIDING WITH PEAK HEATING MAY MAKE IT TOUGH FOR MVFR CIGS TO DEVELOP EVEN AS EARLY AS 6Z TAF HAS IT. CONFIDENCE MUCH HIGHER IN TSRA IMPACTING THE FIELD WED NIGHT...THOUGH LESS CONFIDENCE ON TIMING. THE WARM FRONT LOOKS TO SURGE NORTH AFTER 00Z...WHICH SHOULD AID IN THE RAPID EXPANSION OF TSRA ACROSS MN. ONCE STORMS START...COULD BE A VERY LONG NIGHT FOR SEEING ACTIVITY IN THE AREA. /OUTLOOK FOR KMSP/ THU...VFR EARLY WITH IFR/TSRA LIKELY IN THE AFTERNOON. SOME STORMS MAY BE SEVERE. WINDS SE BECOMING S AT 10G20KTS. FRI...MVFR EARLY...THEN VFR. WINDS W AT 10G20KTS. SAT...VFR. WINDS S 5-10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...BORGHOFF LONG TERM...DWE AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
910 PM CDT THU MAY 8 2014 .UPDATE... A FEW SHOWERS MOVING INTO THE WESTERN PART OF THE CWA CURRENTLY. WITH A DECENT LAYER OF VERY DRY AIR IN THE MID-LEVELS...THESE SHOWERS WILL HAVE DIFFICULTY REACHING THE GROUND THE FURTHER EAST THEY TRAVEL. HOWEVER...MOISTURE WILL BE INCREASING FROM THE SOUTHWEST THROUGH THE NIGHT AND SO BY MORNING A WIDESPREAD SWATH OF RAINFALL CAN BE EXPECTED TO TAKE OVER MUCH OF THE AREA. STILL NOT EXPECTING ANY SEVERE STORMS WITH THIS ACTIVITY. UPDATED THE POPS TO COVER THE APPROACHING RAINFALL OVERNIGHT AND TOOK OUT THE MENTION OF THUNDER IN MOST OF THE AREA OVERNIGHT AS WELL. /10/ && .AVIATION... VFR CONDITIONS CURRENTLY PREVAIL WITH THICK MID AND HIGH LEVEL CLOUDINESS ACROSS MOST AREAS. DEEPER AND RICHER LOW LEVEL MOISTURE REMAINS S AND W OF AREA PER SURFACE OBS AND 00Z SOUNDINGS. EXPECT THIS MOISTURE TO INCREASE ACROSS AREA TONIGHT...WITH DEVELOPMENT OF STRATUS FROM THE S. HRRR RUNS SHOW VFR CONDITIONS GENERALLY HOLDING THROUGH AT LEAST 06Z...WITH DETERIORATION TO MVFR AND POTENTIALLY IFR THROUGH 12Z. LOWEST CIGS/VSBYS EXPECTED IN SE AREAS WHERE SOMEWHAT WEAKER LOW LEVEL FLOW SHOULD EXIST. HIGH RESOLUTION MODELS AGREE ON CONVECTION WORKING INTO AREA FROM WEST WITH GREATEST COVERAGE THROUGH 18Z REMAINING WEST OF I-55. WILL CARRY SOME CATEGORICAL MVFR CIGS/VSBYS IN RA WITH VCTS THESE AREAS. /08/ && .PREV DISCUSSION... /ISSUED 355 PM CDT THU MAY 8 2014/ SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...MOISTURE WILL BE ON THE INCREASE TONIGHT FROM THE WEST AS A DISTURBANCE APPROACHES THE REGION. SOME SHOWER AND STORM ACTIVITY LOOKS POSSIBLE AFTER MIDNIGHT INTO EARLY FRIDAY MORNING ESPECIALLY ACROSS THE DELTA REGION. INSTABILITY LOOKS SUFFICIENT FOR SOME STRONG STORMS TO DEVELOP...WITH AN ISOLATED SEVERE STORM NOT OUT OF THE QUESTION. SHOWERS AND STORMS WILL CONTINUE INTO FRIDAY AFTERNOON AND EVENING AS ANOTHER SHORT WAVE MOVES ACROSS THE AREA. SOME STORMS COULD PRODUCE 1-3 INCHES OF RAIN AND GUSTY WINDS OF 40-50 MPH. SOUTHERLY FLOW CONTINUING SATURDAY WILL ALLOW FOR DECENT MOISTURE TRANSPORT...ALLOWING FOR THE POSSIBILITY FOR MORE SHOWER AND THUNDERSTORM ACTIVITY. SOME STRONG STORMS WILL BE POSSIBLE AS WELL. /27/ LONG TERM...SUNDAY THROUGH MUCH OF NEXT WORK WEEK...MID TO UPPER LEVEL FLOW SHOULD WEAKEN RATHER SUBSTANTIALLY OVER OUR REGION AS THE WESTERLIES BEGIN TO CONSOLIDATE TOWARD A BUILDING TROUGH IN THE WESTERN CONUS. DESPITE THIS EVOLUTION EXPECT MOIST SOUTHERLY FLOW OFF THE GULF OF MEXICO TO CONTINUE INTO THE LOWER MISSISSIPPI VALLEY PROVIDING ENOUGH INSTABILITY IN THE AFTERNOON TO FUEL ISOLATED SHOWERS AND STORMS. RATHER TAME LAPSE RATES AND LACKLUSTER SHEAR SHOULD GREATLY LIMIT THE RISK OF HAZARDOUS WEATHER THROUGH MONDAY. MODELS STILL SHOWS SOME MINOR TIMING DIFFERENCES ASSOCIATED WITH A DECENT COLD FRONT EXPECTED TO PUSH THROUGH FROM THE NORTHWEST ON TUESDAY...BUT WE REMAIN CONFIDENT IT SHOULD CLEAR THE REGION TO THE EAST BY WEDNESDAY. SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH FROPA...BUT INDICATIONS ARE THAT ACTIVITY WILL BE LARGELY ANAFRONTAL (WHICH WILL AGAIN GREATLY LIMIT THE POTENTIAL FOR HAZARDOUS WEATHER). TEMPERATURES WILL CONTINUE TO RUN ABOVE NORMAL UNTIL THIS FRONT PASSES...BUT A PLEASANT TREND TOWARD AT LEAST SLIGHTLY BELOW AVERAGE TEMPS AND DRY WEATHER IS ANTICIPATED FOR SEVERAL DAYS FOLLOWING FRONTAL PASSAGE. /BB/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 68 82 65 85 / 43 75 43 35 MERIDIAN 66 82 64 85 / 24 77 62 39 VICKSBURG 68 84 67 86 / 52 62 30 32 HATTIESBURG 69 84 66 86 / 16 74 56 58 NATCHEZ 70 83 67 85 / 51 50 29 43 GREENVILLE 69 83 67 86 / 50 68 45 28 GREENWOOD 69 82 66 85 / 46 74 51 29 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
921 PM CDT Thu May 8 2014 .UPDATE: Issued at 853 PM CDT Thu May 8 2014 A north to south area or band of showers and a few thunderstorms was moving slowly eastward through east central and southeast MO and west central and southwest IL. The intensity of the radar returns have weakened over the St Louis metro area with better rains both north and south. This precipitation was in a region of low-mid level warm air advection ahead of a southwest flow shortwave. This activity will eventually translate east of our forecast area later this evening, with a break in the precipitation expected until more showers and storms now across northwest and west central MO and southeast KS, along and just ahead of an approaching cold front, shifts into our forecast area late tonight. The HRRR model also tries to bring some of the convection now across AR northeastward into southeastern MO late tonight. Could not rule out isolated hail and strong wind gusts from the stronger storms late tonight. Mild temperatures should continue tonight with slight cooling, or cooler temperatures over the extreme northwestern portion of our forecast area behind the cold front. GKS && .SHORT TERM: (Through Late Tonight) Issued at 256 PM CDT Thu May 8 2014 SHRA/TSRA trends are the primary concern this evening, and are remaining very difficult to pin down. Early on, N-S band of showers and thunderstorms now moving into central MO will work its way east during the remainder of the afternoon and early evening. Have leaned heavily on the HRRR runs for trends over the next 3-6 hours, as it continues to provide superior guidance on the trends with this area of convection. Passage of the shortwave fueling this precip will likely cause area to diminish a bit in coverage and intensity during the evening, but additional (and hard to time) upstream shortwaves, as well as persistent WAA and associated isentropic ascent, should generate additional shower and thunderstorm activity during the late evening and overnight hours in the warm sector. Precip threat (especially in our NW counties) will also be driven by convection that forms along the cold front and works its way east with time. Truett .LONG TERM: (Friday through Next Thursday) Issued at 256 PM CDT Thu May 8 2014 Overnight elevated SHRA/TSRA forced by the LLJ will probably be ongoing at daybreak on Fri, at least over part of the CWA. As the core of the LLJ shifts northeastward into IL/IN, the greatest moisture convergence and forcing for pcpn will also shift out of the CWA. Consequently, there should be a decrease in precipitation coverage or perhaps even a lull during the mid to late morning hours on Fri. The absence of widespread precipitation combined with some breaks in the clouds should be sufficient for afternoon destabilization across the southeastern one-half to one-third of the CWA. This detail matters because a trough with a vort max in its base will be approaching from the west. Large scale ascent from DCVA as well as lift ahead of the cold front will likely occur in an environment with H7-H5 lapse rates of 6-7.5 deg C/km and 40-60 kts of 0-6 km bulk shear as well as nearly unidirectional wind profiles. These parameters are sufficient for severe thunderstorms with hail and wind as the primary threats. Although recent model runs all depict a solution where the cold front moves through most of the CWA on Fri night and then stalls in southern MO before lifting northward as a warm front on Sat, the effective boundary might end up much farther south by Sat morning depending on outflow boundaries from convection on Fri/Fri night. If this occurs, then the temperature forecast for Sat may be too warm. Shortwave ridging aloft is expected on Sat with a compact vort max moving across southern MN, which is much farther north than yesterday`s model runs. The H85 LLJ associated with the vort max moving across MN could produce enough lift over the warm front to support scattered SHRA/TSRA in MO/IL, especially if forecast H7-H5 lapse rates of 7-8 deg C/km are realized. SHRA/TSRA are also possible on Sat night due to moisture convergence along a strengthening southwesterly LLJ. A new trough develops out west over the weekend, inducing surface cyclogenesis over the plains and eventually sending another cold front through MO/IL early next week. Models disagree on how quickly the trough shifts eastward into the central CONUS, leading to disagreements on how quickly the cold front moves through the LSX CWA. It appears that there will be a period of northwest flow or cyclonic flow during the middle of next week depending on how the trough evolves. Expect cooler temperatures in such a pattern with precip chances dependent on shortwaves and moisture availability. Kanofsky && .AVIATION: (For the 00z TAFs through 00z Friday Evening) Issued at 601 PM CDT Thu May 8 2014 Band of showers and thunderstorms will continue to move east this evening. The rain will be moving out of KCOU soon, but persist at KUIN through mid evening, and will soon move into the St. Louis metro TAF sites and persist through 04-05Z. Expect MVFR conditions with the rain, and some of the heavier cores could briefly produce IFR visibilities. This band will then move out and expect a period of dry and VFR conditions before another round of showers and scattered thunderstorms moves through the area overnight and early Friday morning. This will coincide with an area of low MVFR ceilings that will persist through mid-late morning before slowly improving to VFR. Specifics for KSTL: Showers and thunderstorms will move into the terminal by 01Z, though scattered thunderstorms will be in the area before then. Expect MVFR conditions with the rain. This first area of rain will move out around 04Z, but then expect another round of showers and scattered thunderstorms to move through the terminal starting around 09Z. Low MVFR conditions are expected with this second round that will persist after the rain ends. VFR ceilings are not expected until midday. Thunderstorms are expected to develop in the vicinity of KSTL tomorrow afternoon and then move east of the airport by 00Z. Britt && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
754 PM CDT Thu May 8 2014 .UPDATE... Issued at 730 PM CDT THU MAY 8 2014 Surprisingly busy evening. Shield of rain with embedded convection has proved to be interesting, with some isolated damage reports with brief bowing/spin up vorts in shallow convective cells/elements. Low level 0-1km helicity actually fairly stout over the Mo Ozarks this afternoon/evening. Overall trend of the eastern cwfa convection is downward and expect that trend to continue. Deeper scattered convection is occurring ahead of a cold front over eastern KS with the most notable updrafts w-nw-n of KCNU. Storms having a tough time of it, but still seeing a stronger updraft or two firing up. MLCAPE of around 1000 J/kg is occurring just ahead of the front, but drops off quite a bit has you head east-se into MO. 0-6km bulk shear more than adequate for storm organization where somewhat stronger instability occurs over se KS and far western MO later this evening. HRRR however, really not doing much with the existing convection owing to a lack of progged overall instability. Will watch trends, but the weakening trend of the HRRR looks good later this evening. Later tonight, a veering low level jet and moisture advection should allow some additional elevated convection to develop overnight into Friday morning ahead of the low level front with the approach of shortwave/upper jet max. && .SHORT TERM...(This Evening and Tonight) Issued at 300 PM CDT THU MAY 8 2014 An upper level trough is currently pushing east into the central Plains as an associated area of surface low pressure pushes northeast across eastern Nebraska. A cold front ALSO extends south from the low and is pushing east across central Kansas and Oklahoma. Convection is ongoing across the area. This activity formed over Oklahoma overnight and continues to develop and push to the northeast. These showers and thunderstorms will continue to track northeast across the area this afternoon into the early evening hours. Deep layer shear is on the weak side across the area. Instability is starting to increase across the eastern Ozarks as more heating was able to occur in these locations before clouds were able to overspread the area. The overall severe potential is on the low side with this activity, but with slightly better instability there could be a few strong wind gusts with any bow segments that can develop this afternoon and early this evening. This activity will push east of the area by the early to mid evening hours. The clouds are clearing from west to east across eastern Kansas into central Oklahoma behind this convection. We will have to see how far east the clearing can make it this afternoon/early this evening. The clearing will likely make it over to the far western portion of the forecast area. Additional thunderstorms are expected to develop across northeastern Oklahoma into eastern Kansas along a cold front late this afternoon into this evening. This activity will then track to the northeast and may clip southeastern Kansas and far western Missouri. Deep layer wind shear will begin to increase from west to east this evening and if enough clearing occurs and enough instability can develop, hail in excess of quarters will be possible with stronger storms. These storms may congeal into a line and track east across the area. If the line does develop winds in excess of 60mph will be possible. There would also be a small risk for a brief tornado within this line generally northwest of a Columbus Kansas to Osceola Missouri Line this evening. The cold front will then slowly sag southeast towards the area late this evening into the overnight hours. Showers and thunderstorms are expected to develop and ride along the front overnight. The front will push over the far northern and western portions of the forecast area tonight. Locally heavy rainfall will occur where the training of storms can occur along the front. Due to the dry antecedent conditions the overall flood risk is low with this potential heavy rainfall. .LONG TERM...(Friday through Thursday) Issued at 300 PM CDT THU MAY 8 2014 An active weather pattern will continue Friday into early next week as the a couple storm system track through the region. Any convection that develops overnight tonight should push east of the area by Friday morning, with clearing expected behind this activity. The cold front will continue to track southeast through the area on Friday. Areas southeast of the front will become unstable. Better deep layer shear will be over the region on Friday afternoon allowing organized updrafts. Additional thunderstorms will develop along the front, and these storms will have the potential to become strong a severe. The main risk will be large hail with a few of the strongest storms capable of hail to golf balls generally along and southeast of the Interstate 44 corridor. The front will push south of the area Friday evening with dry conditions overnight Friday. The front will then lift back north across the area Saturday. Thunderstorms area expected to develop along and north of the front as it lifts through the region. A few of these storms could become strong to severe with large hail the main risk. South of the front instability will increase but there will not be much in a way of lift, and a cap will be increasing through the day as a warm air mass in the mid level spreads over the area. So, think all in all most of the activity will occur along and ahead of the front on Saturday. Another upper level system will track through the region late this weekend into early next week. Medium range models continue to differ on the track, timing, and strength of this system. The cold front will sag south then sweep through the region as the upper level trough approaches and sweeps through the region. Additional severe storm potential will be possible, but details/evolution of storms are lacking this far out in time. Northwest flow aloft pattern will setup over the region behind this system through the middle of next week behind this system. Cooler conditions will occur across the region in this northwest flow pattern. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) Issued at 730 PM CDT THU MAY 8 2014 For the KSGF/KJLN/KBBG tafs: Expect periods of showers/thunderstorms to be possible as a sfc front approaches the region. Best chances for precip and lower ceilings, mvfr/possible ifr at times, will be the 06z-15z time frame as an upper level disturbance moves through the region. Lower ceilings should improve after 15z with precip exiting the area and diurnal heating allowing lower ceilings to lift. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ UPDATE...DSA SHORT TERM...Wise LONG TERM...Wise AVIATION...DSA
AREA FORECAST DISCUSSION
NWS BILLINGS MT
324 PM MDT WED MAY 7 2014 .SHORT TERM...VALID FOR THU AND FRI... AREAS OF RAIN/SNOW CONTINUE THIS AFTERNOON AS WE CONTINUE TO BE AFFECTED BY SLOW MOVING TROF OVER THE NORTHERN/CENTRAL ROCKIES AND DEEP UPSLOPE FLOW...THOUGH WITH DIMINISHED PCPN RATES. MID AND UPPER LEVEL DRY SLOTTING IS IMPACTING OUR SOUTH CENTRAL AND SOUTHEAST PARTS...SO HAVE DROPPED THE ADVISORY FOR THE BIG HORNS. COLDER TOPS CONTINUE FOR OUR WEST...AND SOME CONVECTION IN WESTERN WY MAY FEED INTO THE MTNS OVER THE NEXT FEW HOURS...SO WILL LET THE WARNING FOR THE BEARTOOTH ABSAROKAS RIDE INTO THE EVENING. COLE CREEK SNOTEL IN THE MTNS ABOVE RED LODGE HAS ALREADY PICKED UP AT LEAST A FOOT OF SNOW SINCE YESTERDAY. OTHERWISE...ONLY LIGHT PCPN EXPECTED INTO THIS EVENING WITH A GRADUAL TAPERING OFF TONIGHT AS BEGIN TO PULL IN DRIER AIR FROM THE NW. SFC RIDGING IN EASTERN MT SUPPORTS LIGHT WINDS TONIGHT...WHICH ALONG WITH THE ABUNDANT LOW LEVEL MOISTURE IN PLACE SHOULD RESULT IN SOME FOG TONIGHT ESPECIALLY WITH A LITTLE CLEARING FROM THE NW LATER ON. 12Z GUIDANCE NOT SHOWING MUCH BUT RECENT RAP RUNS SEEM TO BE TRENDING TOWARD BETTER FOG POTENTIAL AFTER MIDNIGHT. HAVE ADDED FOG TO THE FORECAST FROM 06-15Z. OTHER IMPACT TONIGHT WILL BE FREEZING TEMPS FOR MUCH OF THE REGION...SO TAKE PRECAUTIONS IF YOU HAVE SENSITIVE PLANTS OUTDOORS. QUIET DAY IN STORE TOMORROW AS HEIGHTS BUILD FROM THE WEST AND WE BEGIN TO WARM UP. ENERGY COMING OUT OF THE CENTRAL ROCKIES WILL ALMOST ENTIRELY MISS OUR CWA TO THE SE...SO A DRY FORECAST LOOKS GOOD FOR TOMORROW AFTER SOME EARLY MORNING FOG OR LIGHT RAIN/SNOW SHOWERS. HIGHS THURSDAY WILL REACH THE 50S TO LOW 60S...WARMEST WEST. NEXT PACIFIC SHORTWAVE WILL PUSH INTO THE NORTHERN ROCKIES FRIDAY...GIVING US A GOOD CHANCE OF SHOWERS AND A FEW THUNDERSTORMS. LATEST MODEL TRENDS ARE A BIT FASTER WITH THIS ENERGY SO COULD SEE SHOWERS IN OUR WEST BY MORNING...SO NOT QUITE AS GOOD A CONVECTIVE OPPORTUNITY AS A RESULT FOR OUR WEST. NONETHELESS WITH GOOD QG FORCING HAVE RAISED POPS FRI AND FRI NITE. MID LEVEL TEMPS WILL COOL ENOUGH TO TURN PCPN BACK TO SNOW FOR OUR MTNS BY FRI EVENING...WITH A BIT OF ACCUMULATION FOR THE MTNS FRI NITE. SHOULD ALSO SEE SOME GUSTY W-NW WINDS FRI AFTN AND EVENING PER THE FRONTAL PASSAGE AND SHOWER ACTIVITY. HIGH TEMPS ON FRI WILL REACH THE 60S...AND PERHAPS NEAR 70 IN OUR EAST W/ LATER FROPA. JKL .LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED... MODELS ARE COMING INTO BETTER AGREEMENT IN THE EXTENDED PERIOD. THIS COMING WEEKEND WILL BE SOMEWHAT WET...AFTER A WARMER FRIDAY...AS A SHORTWAVE MAKES ITS WAY THROUGH SOUTHERN MONTANA. SNOW LEVELS WILL REMAIN AROUND 6000 FT ACROSS THE REGION...SO MOST OF THE PRECIP SHOULD BE IN THE FORM OF RAIN AT LOWER ELEVATIONS. AT HIGHER ELEVATIONS...ADDITIONAL SNOW ACCUMULATION IS POSSIBLE. INTO NEXT WEEK...THE REGION WILL BE UNDER THE INFLUENCE OF NORTHWESTERLY FLOW ALOFT ON THE EASTERN SIDE OF A RIDGE. SEVERAL SHORTWAVES WILL ATTEMPT TO RIDE THIS RIDGE INTO SOUTH CENTRAL MONTANA. THEREFORE...HAVE KEPT POP VALUES AROUND CLIMO UNTIL CERTAINTY BECOMES CLEARER. TEMPS WILL REMAIN FAIRLY MILD WELL INTO NEXT WEEK WITH NO SIGNIFICANT WARMUP IN SIGHT. THE COOLER TEMPERATURES WILL STUNT THE MELTING OF HIGHER ELEVATION SNOWPACK ANOTHER WEEK. SINGER && .AVIATION... STILL SOME LINGERING RAIN AND SNOW SHOWERS IN AND AROUND KBIL...KMLS...AND KSHR THIS AFTERNOON AS THE STORM SYSTEM WORKS ITS WAY EASTWARD. MOST OF THIS ACTIVITY SHOULD WIND DOWN BY THE EARLY EVENING HOURS. THE POTENTIAL FOR FOG WILL PRESENT ITSELF...ESPECIALLY AT KBIL...DURING THE OVERNIGHT HOURS CAUSING POTENTIAL VISIBILITY ISSUES. SINGER && .PRELIMINARY POINT TEMP/POPS... THU FRI SAT SUN MON TUE WED ----------------------------------------------------------- BIL 030/057 040/065 043/058 038/057 040/062 042/065 043/062 51/B 04/T 55/W 43/W 33/W 22/W 44/W LVM 025/061 037/061 036/055 035/056 035/059 038/064 039/064 51/U 16/T 55/W 43/W 33/W 32/W 22/W HDN 032/057 033/068 039/060 034/060 037/064 039/067 040/064 51/B 03/T 64/W 53/W 33/W 22/W 44/W MLS 033/057 035/069 043/059 037/058 038/062 041/064 042/060 31/B 02/T 55/W 52/W 23/W 23/W 44/W 4BQ 032/054 034/068 041/059 035/058 036/061 039/064 040/060 52/W 01/B 54/W 32/W 23/W 22/W 33/W BHK 033/054 032/067 041/059 035/056 036/058 038/060 039/057 31/B 01/U 55/W 42/W 22/W 23/W 33/W SHR 031/054 031/065 038/056 032/055 034/059 036/063 037/062 52/W 02/T 54/W 44/W 34/W 33/W 33/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER STORM WARNING IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR ZONE 67. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
357 PM CDT WED MAY 7 2014 .SHORT TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 352 PM CDT WED MAY 7 2014 CHANCES FOR THUNDERSTORMS TONIGHT AND THURSDAY ARE THE PRIMARY FORECAST CONCERNS. EARLY AFTERNOON SURFACE ANALYSIS SHOWED A FRONTAL BOUNDARY EXTENDING FROM LOW PRESSURE IN SOUTHEAST SOUTH DAKOTA SOUTHWEST THROUGH NORTHEAST NEBRASKA. NORTHEAST WINDS NORTHWEST OF THE FRONT WERE KEEPING TEMPERATURES IN THE 70S THERE...WHILE GUSTY SOUTH WINDS SOUTHEAST OF THE FRONT HAD PUSHED TEMPS WELL INTO THE 80S WITH SOME 90S ALSO SEEN/EXPECTED. IN OUR SOUTHWEST CWA...DEEPER MIXING WAS OCCURRING...WITH WINDS BECOMING SOUTHWESTERLY WHICH WERE DRYING LOW LEVELS AND BOOSTING TEMPERATURES. RELATIVE HUMIDITIES CLOSE TO 15 PERCENT WERE NOSING INTO JEFFERSON/SALINE COUNTIES AS OF 2 PM...AND WILL LIKELY SPREAD EAST ACROSS RED FLAG WARNING AREA THROUGH THE AFTERNOON. SO WILL KEEP THAT GOING INTO THE EVENING. A COUPLE OF AREAS OF POTENTIAL CONVECTION WERE OF NOTE AT EARLY AFTERNOON. ONE EXTENDING FROM NORTH CENTRAL NEBRASKA INTO SOUTH DAKOTA...AND THE OTHER ACROSS CENTRAL KANSAS. CONGESTUS-LOOKING CLOUDS WERE TRYING TO IGNITE IN NORTH CENTRAL NEBRASKA...AND CLOUD TOP COOLING ALGORITHMS WERE SUGGESTING A SMALL CHANCE FOR THOSE CLOUDS TO CONVECT. BUT IF THEY DO...THEY WILL MOST LIKELY RIDE NORTH- NORTHEAST INTO SOUTH DAKOTA. SIGNIFICANT CONVECTIVE INHIBITION WAS NOTED OVER THIS AREA...SO THERE IS A MUCH BETTER CHANCE NOTHING WILL GO CLOSE TO OUR AREA...FOCUSING ACTIVITY MORE IN WESTERN NEBRASKA AND THE FOOTHILLS WHERE INHIBITION IS LOW. KANSAS POTENTIAL CONVECTION WAS BUBBLING UP UNDER INCREASING MID LEVEL WIND FIELD AHEAD OF TROUGH APPROACHING THE SOUTHERN ROCKIES...AND WHERE SURFACE TEMPERATURES WERE WELL INTO THE 90S. DRYLINE WAS IN THIS AREA AS WELL...ADDING LOW LEVEL CONVERGENCE INTO THE MIX. ALSO OF NOTE...MESOSCALE MODELS RAP AND HRRR ALONG WITH NAM12 EVENTUALLY BUBBLE CONVECTION NORTH AND NORTHEAST OF THIS AREA LATER THIS EVENING...AND MOVE THAT INTO EASTERN NEBRASKA AND SOUTHWEST IOWA WHERE INTERACTION WITH SURFACE FRONT WILL ENHANCE POTENTIAL. CINH IS LOWERING DRAMATICALLY ACROSS SOUTHEAST NEBRASKA WHERE DEW POINTS HAD ONLY MIXED INTO THE 50S...WITH OVER 2000 J/KG MUCAPE AVAILABLE. SO GIVEN INSTABILITY...FRONT IN THE AREA...AND A PREPONDERANCE OF MODEL DATA FIRING CONVECTION...WILL ADD AT LEAST SMALL POPS TO MOST OF OUR AREA THIS EVENING AND OVERNIGHT. SOME STORMS COULD APPROACH SEVERE...WITH AT LEAST SMALL HAIL AND GUSTY WINDS POSSIBLE. THEN LATER TONIGHT...STORMS FIRING IN THE NEBRASKA PANHANDLE REGION IS FORECAST TO SLOWLY SHIFT EAST-NORTHEAST OVERNIGHT...AND COULD REACH PARTS OF NORTHEAST NEBRASKA BEFORE MORNING. OTHERWISE EXPECT ANY MORNING STORMS TO GRADUALLY WORK EAST AND NORTHEAST OF OUR AREA BY MID MORNING BEFORE NEXT POTENTIAL ROUND SETS UP IN THE AFTERNOON. UPPER TROUGH/LOW IS EXPECTED TO EJECT NORTHEAST INTO THE PLAINS ON THURSDAY...REACHING THE DAKOTAS BY LATE AFTERNOON. MEANWHILE TRAILING SURFACE COLD FRONT WILL BE MARCHING EAST INTO EASTERN NEBRASKA IN THE AFTERNOON. VARYING MODEL TIMING OF THIS FEATURE IS STILL APPARENT...BUT WERE BETTER IN LINE SHOWING BEST CONVECTIVE CHANCES NEAR AND EAST OF THE MISSOURI RIVER AT TIME OF MAX HEATING AND INSTABILITY. EXPECT STORMS TO FIRE ALONG COLD FRONT FROM WEST CENTRAL IOWA INTO SOUTHEAST NEBRASKA BY MID/LATE AFTERNOON WHERE SURFACE-BASED CAPES WILL EXCEED 2000 J/KG AND CLOSE TO 50KT OF 0-6KM BULK SHEAR WILL RESIDE. HAIL AND DAMAGING WINDS WILL CERTAINLY BE POSSIBLE WHERE STORMS DO FIRE. STORMS WILL RACE NORTHEAST AS FRONT PUSHES EAST...SO EXPECT MOST CONVECTION TO BE WELL EAST OF OUR AREA BY MID EVENING. SOME LINGERING STORMS WILL BE POSSIBLE IN FAR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA WHERE FRONT WILL BE SLOWER TO CLEAR THOSE AREAS. SOME WRAP-AROUND SHOWERS ARE ALSO POSSIBLE IN NORTHEAST NEBRASKA THURSDAY EVENING. FRIDAY LOOKS DRY AND COOLER BEHIND EXITING FRONT...WITH HIGHS FROM THE UPPER 60S TO LOWER 70S. A QUICK RETURN TO SOUTHERLY LOW LEVEL FLOW DEVELOPS FRIDAY NIGHT AS A TRAILING UPPER WAVE INDUCES SURFACE LOW PRESSURE IN THE HIGH PLAINS. AS WAVE TRACKS EAST ON SATURDAY...SURFACE FRONT WILL ENTER NORTHEAST NEBRASKA IN THE MORNING...THEN INTO NORTHERN KANSAS AND MISSOURI SATURDAY EVENING. SHOWERS AND SOME THUNDERSTORMS WILL BE POSSIBLE WITH THIS FRONT THROUGH THE DAY SATURDAY...WITH TEMPERATURES REMAINING GENERALLY IN THE 70S. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 352 PM CDT WED MAY 7 2014 A STRONGER MID LEVEL TROUGH IS FORECAST TO SETTLE INTO THE ROCKIES BY SUNDAY...THEN PROGRESS INTO THE PLAINS MONDAY AND TUESDAY OF NEXT WEEK. TIMING DIFFERENCES ABOUND BETWEEN GFS/ECMWF AND THEIR ENSEMBLE MEMBERS...BUT ALL POINT TO AN UNSETTLED WEATHER PATTERN AND CHANCES FOR PRECIPITATION AT LEAST INTO MONDAY NIGHT. EXPECT MORE OF AN OVERRUNNING-TYPE SCENARIO FOR OUR AREA AS FRONTAL BOUNDARY REMAIN TO OUR SOUTH FOCUSING CONVECTION ACROSS KANSAS AND MISSOURI. ECMWF HAS TRENDED TOWARD GFS SOLUTION IN THIS REGARD. SO HAVE AT LEAST CHANCE POPS FOR RAIN/SHOWERS ACROSS A GOOD PART OF THE AREA SATURDAY NIGHT INTO MONDAY NIGHT. BEYOND MONDAY NIGHT...EXPECT NORTHWEST FLOW ALOFT TO RULE INTO WEDNESDAY. A SHORTWAVE OR TWO COULD BRING ISOLATED PRECIP CHANCES DURING THIS TIME...BUT MAIN STORY WILL BE COOLER TEMPERATURES WITH HIGHS GENERALLY IN THE 60S. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 116 PM CDT WED MAY 7 2014 SURFACE LOW WAS LOCATED OVER EAST CENTRAL NEBRASKA AT 18Z WITH WARM FRONT BEGINNING TO PIVOT NORTHWEST INTO NORTHEAST NEBRASKA. THIS BOUNDARY IS EXPECTED TO REMAIN ACROSS THE AREA THROUGH THURSDAY MORNING AS A SECONDARY SURFACE WAVE LIFTS NORTHEAST OUT OF COLORADO TOWARDS SOUTHWEST MINNESOTA THURSDAY AFTERNOON. VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT BOTH KLNK AND KOMA AS THEY REMAIN IN THE WARM SECTOR...WHILE MORE VARIABLE CONDITIONS LIKELY AT KOFK WITH A PERIOD OF MVFR CIGS AND VSBY 03Z-12Z AS SHOWERS AND THUNDERSTORMS DEVELOP ON THE NORTH SIDE OF THE FRONTAL BOUNDARY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ050-051- 065>068-078-088>090. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...FOBERT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
353 PM CDT WED MAY 7 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 333 PM CDT WED MAY 7 2014 MAP ANALYSIS INDICATES AN UPPER TROPOSPHERIC LONGWAVE TROUGH AXIS NEARING THE ROCKY MOUNTAIN RANGE...AND A RIDGE OVER THE EASTERN CONUS. A CLOSED UPPER TROPOSPHERIC LOW IS ALSO NOTED EMBEDDED WITHIN THE LONGWAVE TROUGH AXIS. ENHANCED UPPER TROPOSPHERIC JET ENERGY EXTENDS SOUTH ALONG THE WESTERN CONUS COAST. THIS ENHANCED FLOW THEN SPLITS INTO TWO BRANCHES...WITH ONE BRANCH EXTENDING EAST ACROSS THE SOUTHERN CONUS...AND ANOTHER EXTENDING NORTHEAST INTO THE PLAINS AND THEN EAST/SOUTHEAST OVER THE GREAT LAKES REGION AND INTO THE NORTHEASTERN CONUS. UPPER TROPOSPHERIC FLOW OVER OUR AREA MAXES OUT AT AROUND 55KTS NEAR 36000FT AGL PER 12Z SOUNDING DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY SHOWS THE AFOREMENTIONED LONGWAVE TROUGH AXIS AND RIDGE AXIS. WATER VAPOR IMAGERY ALSO SHOWS INCREASED UPPER TROPOSPHERIC MOISTURE EXTENDING FROM THE FOUR CORNERS REGION INTO THE CENTRAL HIGH PLAINS...AS WELL AS FROM SOUTHERN TEXAS INTO THE MID-MISSISSIPPI VALLEY. AN UPPER TROPOSPHERIC DRY INTRUSION IS NOTED MOVING FROM WEST-TEXAS INTO THE SOUTHERN AND CENTRAL PLAINS. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS NOTED OVER WESTERN KANSAS AND EASTERN COLORADO...WITH A WARM FRONT EXTENDING FROM THE LOW NORTHEASTWARD INTO CENTRAL AND EAST-CENTRAL NEBRASKA. ANOTHER AREA OF LOW BAROMETRIC PRESSURE IS NOTED STRENGTHENING ALONG THE LOWER TROPOSPHERIC BAROCLINIC ZONE OVER EAST-CENTRAL NEBRASKA. A DRY LINE IS NOTED EXTENDING SOUTH/SOUTHWEST FROM THIS SECONDARY LOW AND AS OF 20Z WAS NOTED FROM NEAR KBIE...TO NEAR KCNK...TO NEAR KGBD. THE RESULTANT LOWER TROPOSPHERIC WIND FIELD ACROSS OUR AREA REMAINS FROM THE NORTH/NORTHEAST ACROSS OUR NORTH/NORTHWESTERN CWA...WHILE LOCATIONS FARTHER SOUTH/SOUTHEAST...SOUTH OF THE WARM FRONT AND BEHIND THE DRY LINE...HAS TURNED MORE SOUTHWESTERLY. GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SUGGEST THE WESTERN CONUS UPPER TROPOSPHERIC LONGWAVE TROUGH WILL MOVE EAST...WITH THE EMBEDDED CLOSED LOW WEAKENING INTO AN OPEN WAVE AND MOVING EAST/NORTHEAST...AS A NEGATIVELY-TILTED SHORT WAVE...FROM THE CENTRAL HIGH PLAINS INTO PORTIONS OF THE NORTHERN PLAINS THROUGH THE NEXT 24 HOURS. THE AREA OF LOW BAROMETRIC PRESSURE AT THE SURFACE OVER WESTERN KANSAS IS EXPECTED TO MOVE NORTHEAST INTO CENTRAL NEBRASKA BY 12Z THURSDAY...AND INTO SOUTHWESTERN MINNESOTA BY 00Z FRIDAY. AS THE SURFACE LOW MOVES INTO CENTRAL NEBRASKA...THE LOWER TROPOSPHERIC WIND FIELD ACROSS OUR AREA SHOULD BECOME MORE SOUTH/SOUTHWESTERLY TONIGHT...BEFORE BECOMING MORE NORTHWESTERLY DURING THE DAY THURSDAY AS AN ASSOCIATED LOWER TROPOSPHERIC BAROCLINIC ZONE CLEARS THE AREA. THE AFOREMENTIONED UPPER TROPOSPHERIC SHORT WAVE IS EXPECTED TO REMAIN WEST/NORTHWEST OF OUR AREA TONIGHT INTO TOMORROW...THUS KEEPING THE VAST MAJORITY OF RESULTANT OMEGA TO OUR NORTHWEST AS WELL. AS A RESULT...PRECIPITATION PRODUCTION IS ALSO EXPECTED TO REMAIN NORTHWEST OF OUR AREA THIS AFTERNOON INTO THIS EVENING...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC...SREF-MEAN...AS WELL AS SIMULATED REFLECTIVITY FROM THE HRRR...1KM WRF-ARW...1KM WRF-NMM AND 4KM WRF-NMM. THAT BEING SAID...THERE ARE INDICATIONS FROM SOME SIMULATED REFLECTIVITY OUTPUT THAT SOME OF THE HIGH PLAINS CONVECTION COULD BRUSH OUR FAR WESTERN CWA BETWEEN 23Z AND 02Z. ALTHOUGH THE EVENING SHIFT WILL WANT TO MONITOR HIGH PLAINS CONVECTION IN CASE IT TRIES TO MAKE A PUSH EAST INTO OUR WESTERN CWA...FOR NOW WILL MAINTAIN A DRY FORECAST THROUGH THIS EVENING. IT ALSO WORTH MENTIONING THAT VARIOUS SETS OF GUIDANCE SUGGEST CONVECTION COULD BE REALIZED THIS AFTERNOON INTO EARLY THIS EVENING ALONG THE DRY LINE ADVANCING ACROSS THE REGION...BUT SINCE THIS DRY LINE HAS ALREADY CLEARED OUR AREA ANY RESULTANT CONVECTION SHOULD REMAIN SOUTH/SOUTHEAST OF OUR AREA...MORE INTO KANSAS AND SOUTHEASTERN NEBRASKA. OVERNIGHT TONIGHT...GUIDANCE SUGGESTS A ~60KT JET AXIS JUST ABOVE THE BOUNDARY LAYER WILL DEVELOP FROM CENTRAL KANSAS INTO PORTIONS SOUTH CENTRAL NEBRASKA. THERMAL ADVECTION ALONG THIS AXIS AND MOISTURE CONVERGENCE NEAR THE NOSE OF THIS JET APPEAR AS THOUGH THEY WILL BE SUFFICIENT FOR PRECIPITATION PRODUCTION ACROSS MUCH OF THE CWA...A SOLUTION SUPPORTED BY THE NAM...OPERATIONAL GFS ...SREF-MEAN...AS WELL AS SIMULATED REFLECTIVITY FROM THE HRRR AND 1KM WRF-ARW. COVERAGE APPEARS AS THOUGH IT WILL BE SPOTTY AT BEST AND THUS DID NOT WANT TO GO MUCH HIGHER THAN A 20% POP FOR MUCH OF THE CWA...AND SUCH HAS BEEN PRESENTED IN THE OFFICIAL FORECAST FOR THE MOST PART. THE LOWER TROPOSPHERIC JET AXIS SHOULD WEAKEN TOWARDS DAYBREAK THURSDAY AS IT MOVES OFF TO THE EAST...THUS ALLOWING FOR DECREASING POPS ACROSS OUR AREA THURSDAY MORNING. THAT BEING SAID...THERMAL ADVECTION AHEAD OF THE WESTERN CONUS LONGWAVE TROUGH AXIS MAY MOVE JUST FAR ENOUGH EAST TO IMPACT EXTREME WEST/NORTHWEST PORTIONS OF OUR CWA AND AS A RESULT...WENT AHEAD WITH A ~20% POP ACROSS OUR WEST/NORTHWEST DURING THE DAY THURSDAY. LOCATIONS ACROSS OUR EXTREME EAST COULD ALSO OBSERVE ISOLATED CONVECTIVE ACTIVITY BY DURING THE AFTERNOON AS THE AFOREMENTIONED LOWER TROPOSPHERIC BAROCLINIC ZONE CLEARS THE AREA BEHIND THE SURFACE LOW. AS A RESULT...ALSO WENT AHEAD WITH A ~20% POP ACROSS OUR EXTREME EAST FOR THURSDAY AFTERNOON. FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST PARCELS ROOTED TO AROUND 800MB WILL HAVE ~1000J/KG OF POTENTIAL ENERGY WITH MINIMAL CIN. DEEP LAYER BULK SHEAR OF 30-40KTS IS ALSO EXPECTED OVER THE AREA TONIGHT. SO ALTHOUGH THE THREAT FOR LARGE HAIL DOES NOT SEEM OVERLY IMPRESSIVE...WILL CONTINUE TO MENTION THE POTENTIAL FOR A STRONG STORM...WITH HAIL UP TO THE SIZE OF NICKELS...FOR TONIGHT IN THE HWO. FOR TOMORROW AFTERNOON...LITTLE IF ANY POTENTIAL INSTABILITY IS EXPECTED TO EXIST OVER OUR WEST/NORTHWESTERN CWA SO WENT AHEAD WITH NO MENTION OF THUNDER OUT THAT WAY. ACROSS OUR EXTREME EAST IN THE VICINITY OF THE BAROCLINIC ZONE...THE INTRUSION OF A DRIER LOWER TROPOSPHERIC AIR MASS WILL LIKELY PREVENT POTENTIAL INSTABILITY FROM CLIMBING MUCH ABOVE 1000J/KG...ALTHOUGH DEEP LAYER BULK SHEAR COULD APPROACH 50KTS. WILL GO AHEAD AND MENTION HAIL TO THE SIZE OF NICKELS ACROSS OUR EXTREME EAST IN THE HWO FOR THURSDAY AFTERNOON AS A RESULT. INCREASING SOUTHERLY LOWER TROPOSPHERIC FLOW...ALONG WITH INCREASED CLOUD COVER AND POTENTIAL PRECIPITATION...SHOULD HELP PROMOTE ANOTHER WARM NIGHT TONIGHT WITH LOWS IN THE 50S AND 60S CURRENTLY FORECAST. A COOLER LOWER TROPOSPHERIC AIR MASS WILL WORK INTO THE AREA BEHIND THE BAROCLINIC ZONE DURING THE DAY THURSDAY...THUS PROMOTING A COOLER DAY FOR MOST LOCATIONS ON THURSDAY WHEN COMPARED TO WEDNESDAY. THURSDAY HIGHS IN THE 60S AND 70S ARE CURRENTLY FORECAST FOR MOST LOCATIONS ACROSS THE AREA AS A RESULT. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 333 PM CDT WED MAY 7 2014 ALOFT: MULTI-DAY 500 MB MEANS FROM THE GFS AND EC ENSEMBLES SHOW THAT THE LONGWAVE TROF WILL BE OVER THE WRN USA THRU MON 5/12...WITH THE RIDGE OVER THE ERN USA. THE LEAD SHORTWAVE TROF WILL EXIT E OF THE REGION FRI...TEMPORARILY DEAMPLIFYING THE WRN USA TROF/ERN USA RIDGE. THE LOW CURRENTLY OVER THE GULF OF AK WILL DROP INTO THE WRN TROF SAT...RESULTING IN RE-AMPLIFICATION SUN- MON. BY THIS TIME FRAME...THE USUAL MODEL BIASES APPEAR WITH THE 06Z/12Z GFS ON THE FAST SIDE OF THE GUIDANCE ENVELOP...AND THE 00Z/12Z GEM ON THE SLOWEST SIDE. THE LAST 3 RUNS OF THE EC DO FAVOR THE SLOWER GEM. EVEN THE LAST 3 RUNS OF THE UKMET COINCIDE WITH THE GEM. THAT IS GOOD NEWS FOR RAINFALL. THIS RENEWED TROF WILL ADVANCE INTO THE PLAINS TUE AND THEN INTO THE ERN USA WED-FRI WITH NW FLOW DEVELOPING HERE. THE TROF MOVING INTO THE W SAT LOOKS LIKE IT WILL SEND A SHORTWAVE TROF E INTO THE NRN PLAINS WHILE THE REST OF THE ENERGY DROPS INTO THE INTERMOUNTAIN WEST. SURFACE: NRN PLAINS HIGH PRES WILL SLIP S INTO THE REGION THU NIGHT WITH THE COOL FRONT DEPARTING FURTHER TO THE S AND E. A NEW LEE SIDE TROF WILL DEVELOP FRI...WITH AN OCCLUDED LOW ADVANCING THRU THE NRN PLAINS FRI-SAT /ASSOCIATED WITH THE TROF MENTIONED IN THE PREVIOUS PARAGRAPH/. THE COOL FRONT WILL MOVE THRU HERE FRI NIGHT. THAT FRONT WILL THEN BECOME STATIONARY FROM THE SRN PLAINS TO THE GREAT LAKES SUN AS HEIGHTS FALL IN THE W...AND CYCLOGENESIS COMMENCES. THIS LOW WILL TRACK UP THE FRONT...ACROSS KANSAS CITY MON MORNING...AND SHOULD BE OVER IL BY 00Z/TUE BASED ON THE 00Z EC ENSEMBLE MEAN. EXPANSIVE HIGH PRES WILL ENVELOP THE PLAINS TUE- WED. AS FAR AS SENSIBLE WX...THIS MEANS TEMPS WILL AVERAGE COOLER THAN NORMAL FRI-WED...WITH VERY HIGH POTENTIAL FOR AT LEAST 1 DAY OF MUCH COOLER THAN NORMAL TEMPS. RIGHT NOW IT/S MON. ANOTHER VERY GOOD ASPECT OF THIS SYSTEM IS THAT THE EXITING COOL FRONT WILL NOT PLUNGE DEEP INTO THE S. GULF MOISTURE WILL NOT BE FAR AWAY. THE LOW WILL ALSO BE TRACKING S OF THE FCST AREA. THIS COULD RESULT IN BENEFICIAL/SOAKING RAIN FOR PARTS OF THE FCST AREA. THIS REALLY ISNT MODELED YET...BUT THE PATTERN LOOKS FAVORABLE WITH THE FRONT HAVING ANABATIC CHARACTER. THE 16Z WPC EXTENDED FCST DISCUSSION WAS REVIEWED. HAZARDS: TSTMS ARE POSSIBLE SAT NIGHT INTO SUN S-SE OF THE TRI- CITIES. DOESNT CURRENTLY LOOK FAVORABLE FOR SEVERE. THERE IS A LOW PROBABILITY THAT WE MAY NEED A WIND ADVISORY SOMETIME SUN-MON. THE DAILY DETAILS... FRI: CLEARING AS A SHORTWAVE RIDGE MOVES IN DURING THE AFTERNOON. VERY NICE WITH LIGHT WINDS AND NEAR NORMAL TEMPS. FRI NIGHT: INCREASING MID-HIGH CLOUDS AS THE NEGATIVE TILT NRN PLAINS TROF MOVES THRU ALONG WITH THE EXIT REGION OF A 100 KT TROPOPAUSE JET. A SLIGHT CHANCE OF WARM ADVECTION-INDUCED SPRINKLES HAS BEEN INTRODUCED INTO THE FCST PRIMARILY ALONG AND N OF I-80. CLOUD BASES WILL BE NO LOWER THAN 10K FT. SO IT WILL BE TOUGH TO GET MEASURABLE RAIN. SAT: MORNING COOL FRONTAL PASSAGE. THE CHANCE OF MORNING SHWRS/TSTMS WAS WITHDRAWN FROM THE FCST AND REPLACED WITH A SLIGHT CHANCE OF SPRINKLES N AND E OF THE TRI-CITIES. THEN CLEARING AND A LITTLE WARMER. SAT NIGHT: A 50 KT LOW-LEVEL JET /LLJ/ WILL INDUCE STRONG WARM/MOIST AIR ADVECTION AND FRONTOGENESIS. THIS WILL RESULT IN MCS DEVELOPMENT BUT WITH THE LLJ VEERING THRU THE NIGHT...IT IS LIKELY TO BE E OF THE FCST AREA. SUN-MON: LOTS OF DETAILS LEFT TO BE DETERMINED. BELIEVE ODDS ARE VERY HIGH OUR CURRENT HIGH TEMPS ARE WAY TOO WARM BOTH DAYS. WE ARE BASICALLY CARRYING 60-70F. CONSENSUS OF MODEL 2M TEMPS SUGGEST 50S AND THIS LOOKS MUCH MORE REASONABLE. THIS WILL OCCUR WITH BLUSTERY N WINDS. THE BEST CHANCE FOR RAIN IS CURRENTLY SLATED FOR SUN NIGHT INTO MON MORNING...BUT THIS IS ONLY AVERAGE CONFIDENCE DUE TO MODEL DISAGREEMENT. TUE: DRY WITH NEAR NORMAL TEMPS. NW FLOW ALOFT. WED: NW FLOW MAY DELIVER A WEAK SHORTWAVE TROF...POSSIBLY RESULTING IN A FEW LIGHT SHWRS OR SPRINKLES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 132 PM CDT WED MAY 7 2014 VFR CONDITIONS EXPECTED UNTIL 03Z...MVFR CONDITIONS FORECAST 03-14Z...AND THEN VFR CONDITIONS TO FINISH THE FORECAST PERIOD. PERIODIC CLOUD COVER NEAR 4000FT AGL WILL REMAIN POSSIBLE THIS AFTERNOON INTO TONIGHT. THE DEVELOPMENT OF A ~60KT JET AXIS JUST ABOVE THE BOUNDARY LAYER ACROSS PORTIONS OF NORTH CENTRAL KANSAS AND PERHAPS SOUTH CENTRAL NEBRASKA MAY RESULT IN THE DEVELOPMENT OF STRATUS TONIGHT...WITH MULTIPLE SETS OF GUIDANCE SUGGESTING THIS STRATUS WILL IMPACT GRI. GUIDANCE SUGGESTS A CEILING NEAR 2000FT AGL COULD RESULT AND ALTHOUGH CONFIDENCE IS NOT PARTICULARLY HIGH REGARDING THIS STRATUS...WITH MULTIPLE SETS OF GUIDANCE SUGGESTING SUCH CONDITIONS FELT IT PRUDENT TO INTRODUCE MVFR CONDITIONS TO THE TAF AND LET FUTURE SHIFTS ADJUST AS NECESSARY. THERMAL ADVECTION AND MOISTURE CONVERGENCE NEAR THE NOSE OF THE AFOREMENTIONED JET AXIS COULD ALSO PROMOTE ISOLATED PRECIPITATION PRODUCTION NEAR GRI TONIGHT...WITH CONVECTIVE ACTIVITY ALSO NOT OUT OF THE QUESTION. WENT AHEAD WITH VCTS 08-14Z AS A RESULT. INCREASED DIABATIC HEATING AND INCREASING BOUNDARY LAYER HEIGHT AND MIXING POST-SUNRISE ON THURSDAY SHOULD DIMINISH ANY STRATUS THAT IS REALIZED...THUS THE VFR CONDITIONS WHICH ARE FORECAST 14Z ONWARD IN THE TAF. THE SURFACE WIND WILL REMAIN FAIRLY LIGHT AND AT TIMES VARIABLE THIS AFTERNOON INTO TONIGHT...BUT WILL BECOME MORE ESTABLISHED FROM THE SOUTH OR SOUTHWEST DURING THE DAY THURSDAY. THE WEAK LOWER TROPOSPHERIC WIND FIELD...ALONG WITH NEAR-ZERO LOWER TROPOSPHERIC DEW POINT DEPRESSIONS...COULD ALSO RESULT IN PATCHY FOG TONIGHT AT GRI...THUS 5SM IN BR HAS BEEN INTRODUCED INTO THE TAF 08-14Z. && .GID WATCHES/WARNINGS/ADVISORIES... NE...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR NEZ049-063-064- 074>077-083>087. KS...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR KSZ005>007- 017>019. && $$ SHORT TERM...BRYANT LONG TERM...HALBLAUB AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1250 PM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT WED MAY 7 2014 ISOLATED ELEVATED STRONG TO SEVERE THUNDERSTORMS ARE ONGOING THIS MORNING. THE HRRR AND RAP REALLY ARE NOT HANDLING THE STORM TRACK AS THESE METEOROLOGICAL CHALLENGED MODELS PREFER TO TRACK THE ACTIVITY MORE NORTHEAST THROUGH NORTHWEST NEB VS THE WRN SANDHILLS. THIS LIKELY A RESULT OF THE STORM(S) BECOMING ROOTED IN THE LOW LEVEL EASTERLIES. AT ANY RATE THE CURRENT THINKING IS THE STORMS WILL EITHER WEAKEN BEFORE 12Z OR CONTINUE TRACKING TOWARD SCNTL SD. A BLEND OF THE NAM...RAP...ECM...SREF AND THE PREVIOUS FORECAST SUGGESTED SCATTERED POPS THIS MORNING BECOMING LIKELY THIS AFTERNOON. THE RAP HAS ANALYZED A CLOSED H700MB LOW OVER NORTHEAST COLO AT 07Z WHICH LIFTS NORTHEAST THROUGH NWRN NEB THIS MORNING TO FOLLOWED BY A SECOND AND THIRD H7 WAVES THIS AFTERNOON AND EARLY THIS EVENING. THIS WOULD LIKELY KEEP THE WARM SECTOR FROM KIML TO KONL AND SOUTH DRY TODAY. THE NAM SUGGESTS SOME CONVECTION COULD DEVELOP OFF THE FRONT RANGE THIS AFTN AND SWEEP NORTHEAST THROUGH THE SRN AND NERN ZONES. THE THREAT OF SEVERE WEATHER IS OBVIOUS WITH BULK SHEAR 50 KTS OR GREATER AND STEEPENING LAPSE RATES WITH THE APPROACHING 4 CORNERS LOW. SPC HATCHED AN EGG OF VERY LARGE HAIL ACROSS THE WRN SANDHILLS AND PANHANDLE. THIS IS ALONG AND NORTH OF SFC FRONT WHICH IS EXPECTED TO LIFT THROUGH SRN AND NERN NEB LATE THIS AFTN. VERY LARGE HAIL IS POSSIBLE WITH STORMS THIS AFTERNOON AND EVENING AND MOST IF NOT ALL OF THIS SHOULD BE IN THE COLD AIR NORTH OF THE SFC FRONT. THE 5 PERCENT TORNADO AND 15 PERCENT WIND PROBABILITIES WOULD APPEAR CONDITIONALLY TIED TO STORMS FORMING ALONG THE SFC FRONT WHICH LIFTS NORTH OF I-80 AROUND 21Z THIS AFTN AND THEN DROPS BACK SOUTH. SEVERE WEATHER CONTINUES THIS EVENING...PRESUMABLY ELEVATED...WITH THE APPROACH OF THE MAIN UPPER LEVEL LOW. THE NAM AND OTHER MODELS LIFT A DECENT SHOT OF PV15 THROUGH THE FCST AREA. MEANWHILE...LATE SEASON ARCTIC AIR...CURRENTLY IN MONTANA DROPS THROUGH THE HIGH PLAINS FOR A ZONE OF THUNDERSTORMS CHANGING TO WET HEAVY SNOW. THE NAM BACKS THE ELEVATED INSTABILITY RIGHT UP AGAINST THE RAIN SNOW LINE ACROSS SHERIDAN COUNTY AROUND 09Z. THIS MIGHT BE TOO SLOW GIVEN THE PROXIMITY OF THE COLD AIR ACROSS MT AND THE RAIN SNOW LINE OVER NERN WY. THE RAP CAN FIGURE THIS OUT LATER TODAY. FOR NOW THE RAP HAS THE H700MB FREEZING LINE MOVING THROUGH SERN WY AT 00Z THIS EVENING SO A QUICKER CHANGE TO SNOW IS POSSIBLE. THE BEST GUESS ON SNOW AMOUNTS USES THE NAM...GEMREG...SREF AND ECM FOR QPF WITH A 5 OT 1 RATIO FOR UP TO 4 INCHES IN NORTHERN SHERIDAN COUNTY THROUGH 12Z THURSDAY MORNING. LOCALLY HIGHER AMOUNTS COULD DEVELOP ESPECIALLY IF THE CHANGE OVER OCCURS AT 06Z VS THE NAM MODEL SHOWING 09Z. THE RAP HAS BEEN THE BEST PERFORMER THIS SPRING IN RAIN SNOW EVENTS FOLLOWED THE NAM. A WINTER WEATHER ADVISORY IS IN PLACE FOR SHERIDAN COUNTY 09Z-15Z TONIGHT THROUGH THURSDAY MORNING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 335 AM CDT WED MAY 7 2014 LARGE UPPER LEVEL TROUGH WILL CONTINUE TO SHIFT EAST NORTHEAST ACROSS THE CENTRAL PLAINS ON THURSDAY...REACHING THE NORTHERN MISSOURI VALLEY EARLY FRIDAY. IN THE WAKE OF THE UPPER TROUGH ...QUASI-ZONAL FLOW WILL PREVAIL THROUGH MUCH OF THE WEEKEND...BUT EVENTUALLY BREAK DOWN WITH THE APPROACH OF THE NEXT APPRECIABLE WESTERN STATES UPPER TROUGH. THE SURFACE PATTERN FAVORS A NORTHEASTWARD ADVANCING LOW TOWARD MINNESOTA AND FINALLY INTO SOUTHWEST ONTARIO BY EARLY FRIDAY. THIS LOW WILL DRAG A FRONT THROUGH THE CWA LEAVING POST FRONTAL CONDITIONS INTO EARLY FRIDAY...BUT THE LOWER TROPOSPHERIC FLOW WILL RETURN TO SOUTHERLY AS A LEE TROUGH DEVELOPS OFF THE HIGH PLAINS FRIDAY WITH THE APPROACH OF A WEAK NORTHERN PLAINS UPPER WAVE. THIS WAVE...AS IT/S PREDECESSOR...WILL DRAG AN ADDITIONAL FRONT THROUGH THE CWA ON SATURDAY. THE SATURDAY BAROCLINIC ZONE IS FORECAST TO BE WEAK...WITH LITTLE TO NO SENSIBLE CHANGES ANTICIPATED. FOR THURSDAY...WINTER WEATHER ADVISORY ACROSS SHERIDAN COUNTY WILL CONTINUE UNTIL 15Z. ALL THE MEDIUM RANGE DETERMINISTIC MODELS HAVE CONVERGED SOMEWHAT ON A SOLUTION FOR WHICH THERMAL PROFILES WOULD SUPPORT SNOW ACROSS SHERIDAN COUNTY. THERMAL PROFILES INDICATE A DEEP SATURATION...AT TIMES EXTENDING INTO THE DGZ...BUT WARM GROUND TEMPERATURES AND SFC T/S NEAR OR SLIGHTLY ABOVE 0C CREATE LOW CONFIDENCE FORECAST CONCERNING ACCUMULATIONS. SINCE A STRONG DEFORMATION ZONE IS SHOWN TO SET UP IN THIS AREA...CO-LOCATED IN THE TROWAL REGION OF THE SYSTEM...SNOW RATES MAY BE SUFFICIENT TO OVERCOME THE HIGH SUN ANGLE AND WARM TEMPERATURES...BUT CONFIDENCE IS NOT ENOUGH TO EXPIRE THE ADVISORY BEFORE 15Z. CONSEQUENTLY...GIVEN THE STRENGTH OF THE DEFORMATION...SNOW RATES MAY BE SUFFICIENT TO ALLOW FOR SLUSH ACCUMULATION PAST 15Z THURSDAY. FORECAST TIMING WITH THE CURRENT WINTER WEATHER ADVISORY MAY CHANGE WITH NEAR TERM GUIDANCE. WITH LOW LEVEL CAA ONGOING...HIGH TEMPERATURES THURSDAY WILL BE CHILLY...40S FOR THE NORTHWEST...POSSIBLY SOME 60S SOUTHEAST. WILL NEED TO MONITOR CLOUDS THURSDAY NIGHT AND FRIDAY MORNING AS ANY CLEARING WOULD LEAD TO SUB 0C LOWS...WITH THE THREAT OF A LIGHT FREEZE. ATTM...FAVORING THE ECMWF SOLUTION WHICH IS ON SLOWER SIDE...KEEPING SUFFICIENT CLOUDS ACROSS MUCH OF THE FORECAST AREA TO PREVENT A WIDESPREAD FREEZE. ATTM...NORTHWEST NEBRASKA WOULD HAVE THE HIGHEST POTENTIAL OF SEEING A DAMAGING FREEZE /TO YOUNG PLANTS/...ESPECIALLY IF SNOW TOTALS ARE HIGHER THAN CURRENTLY ANTICIPATED. THE ENTIRE NORTH PLATTE CWA HAS NOT REACHED THE 50 PERCENTILE FOR LAST FREEZE DATE...WE DO NOT PLAN TO FROST/FREEZE HEADLINES ATTM. FRIDAY...WITH RETURN FLOW DIRECTING WAA BACK INTO THE CWA...TEMPERATURES SHOULD WARM BACK WELL INTO THE 60S...POSSIBLY LOWER 70S FOR THE ENTIRE CWA. BUT A FAST MOVING WAVE PASSING THROUGH THE QUASI-ZONAL FLOW MAY SPARK OFF A SHOWER OR TWO DURING THE EVENING AND EARLY ON SATURDAY...WITH A WEAK WIND SHIFT TO FOLLOW. AGAIN SATURDAY TEMPERATURES WON/T BE TOO FAR OFF FROM CLIMO...GENERALLY HIGHS IN THE 60S TO LOWER 70S CAN BE EXPECTED FOR MOST IF NOT ALL LOCATIONS. LATE WEEKEND INTO EARLY NEXT WEEK...ANOTHER SYSTEM LOOKS TO MOVE INTO THE CENTRAL ROCKIES SATURDAY NIGHT AND EMERGE ONTO THE PLAINS SUNDAY AND MONDAY. WIDESPREAD PRECIPITATION WILL BE POSSIBLE...AND DESPITE DIFFERENCES WITH THE HANDLING OF THE SYSTEM...WILL MAINTAIN 30-40 POPS LATE WEEKEND INTO EARLY NEXT WEEK FOR MUCH OF THE CWA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1249 PM CDT WED MAY 7 2014 COMPLEX STORM SYSTEM TO BRING AN ARRAY OF WEATHER TO THE AREA THIS AFTERNOON THROUGH TOMORROW MORNING. THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND LIFT TO THE NORTHEAST ACROSS THE AREA. THESE STORMS COULD PRODUCE SOME LARGE HAIL AND DAMAGING WINDS. DID INCLUDE TSRA AT KLBF...HOWEVER KLBF LIKELY TO BE ON THE EAST SIDE OF THE ACTIVITY. HIGHER CONFIDENCE KVTN WILL SEE AN IMPACT FROM THUNDERSTORMS. THEN A COLD FRONT WILL PUSH ACROSS THE AREA WITH MVFR CIGS...POSSIBLY IFR CIGS...BEHIND THE FRONT. WINDS INCREASE BEHIND THE FRONT AND NORTHERN NEB...INCLUDING THE KVTN AREA...WILL SEE RAIN SHOWERS. FAR NORTHWEST NEBRASKA COULD SEE SOME SNOW LATE TONIGHT INTO TOMORROW MORNING. CONDITIONS IMPROVE TOMORROW MORNING...ESPECIALLY IN THE SOUTHWEST PART OF NEBRASKA. && .LBF WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM MDT THURSDAY FOR NEZ004. && $$ SHORT TERM...CDC LONG TERM...JACOBS AVIATION...MASEK
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
633 AM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT WED MAY 7 2014 ISOLATED ELEVATED STRONG TO SEVERE THUNDERSTORMS ARE ONGOING THIS MORNING. THE HRRR AND RAP REALLY ARE NOT HANDLING THE STORM TRACK AS THESE METEOROLOGICAL CHALLENGED MODELS PREFER TO TRACK THE ACTIVITY MORE NORTHEAST THROUGH NORTHWEST NEB VS THE WRN SANDHILLS. THIS LIKELY A RESULT OF THE STORM(S) BECOMING ROOTED IN THE LOW LEVEL EASTERLIES. AT ANY RATE THE CURRENT THINKING IS THE STORMS WILL EITHER WEAKEN BEFORE 12Z OR CONTINUE TRACKING TOWARD SCNTL SD. A BLEND OF THE NAM...RAP...ECM...SREF AND THE PREVIOUS FORECAST SUGGESTED SCATTERED POPS THIS MORNING BECOMING LIKELY THIS AFTERNOON. THE RAP HAS ANALYZED A CLOSED H700MB LOW OVER NORTHEAST COLO AT 07Z WHICH LIFTS NORTHEAST THROUGH NWRN NEB THIS MORNING TO FOLLOWED BY A SECOND AND THIRD H7 WAVES THIS AFTERNOON AND EARLY THIS EVENING. THIS WOULD LIKELY KEEP THE WARM SECTOR FROM KIML TO KONL AND SOUTH DRY TODAY. THE NAM SUGGESTS SOME CONVECTION COULD DEVELOP OFF THE FRONT RANGE THIS AFTN AND SWEEP NORTHEAST THROUGH THE SRN AND NERN ZONES. THE THREAT OF SEVERE WEATHER IS OBVIOUS WITH BULK SHEAR 50 KTS OR GREATER AND STEEPENING LAPSE RATES WITH THE APPROACHING 4 CORNERS LOW. SPC HATCHED AN EGG OF VERY LARGE HAIL ACROSS THE WRN SANDHILLS AND PANHANDLE. THIS IS ALONG AND NORTH OF SFC FRONT WHICH IS EXPECTED TO LIFT THROUGH SRN AND NERN NEB LATE THIS AFTN. VERY LARGE HAIL IS POSSIBLE WITH STORMS THIS AFTERNOON AND EVENING AND MOST IF NOT ALL OF THIS SHOULD BE IN THE COLD AIR NORTH OF THE SFC FRONT. THE 5 PERCENT TORNADO AND 15 PERCENT WIND PROBABILITIES WOULD APPEAR CONDITIONALLY TIED TO STORMS FORMING ALONG THE SFC FRONT WHICH LIFTS NORTH OF I-80 AROUND 21Z THIS AFTN AND THEN DROPS BACK SOUTH. SEVERE WEATHER CONTINUES THIS EVENING...PRESUMABLY ELEVATED...WITH THE APPROACH OF THE MAIN UPPER LEVEL LOW. THE NAM AND OTHER MODELS LIFT A DECENT SHOT OF PV15 THROUGH THE FCST AREA. MEANWHILE...LATE SEASON ARCTIC AIR...CURRENTLY IN MONTANA DROPS THROUGH THE HIGH PLAINS FOR A ZONE OF THUNDERSTORMS CHANGING TO WET HEAVY SNOW. THE NAM BACKS THE ELEVATED INSTABILITY RIGHT UP AGAINST THE RAIN SNOW LINE ACROSS SHERIDAN COUNTY AROUND 09Z. THIS MIGHT BE TOO SLOW GIVEN THE PROXIMITY OF THE COLD AIR ACROSS MT AND THE RAIN SNOW LINE OVER NERN WY. THE RAP CAN FIGURE THIS OUT LATER TODAY. FOR NOW THE RAP HAS THE H700MB FREEZING LINE MOVING THROUGH SERN WY AT 00Z THIS EVENING SO A QUICKER CHANGE TO SNOW IS POSSIBLE. THE BEST GUESS ON SNOW AMOUNTS USES THE NAM...GEMREG...SREF AND ECM FOR QPF WITH A 5 OT 1 RATIO FOR UP TO 4 INCHES IN NORTHERN SHERIDAN COUNTY THROUGH 12Z THURSDAY MORING. LOCALLY HIGHER AMOUNTS COULD DEVELOP ESPECIALLY IF THE CHANGE OVER OCCURS AT 06Z VS THE NAM MODEL SHOWING 09Z. THE RAP HAS BEEN THE BEST PERFORMER THIS SPRING IN RAIN SNOW EVENTS FOLLOWED THE NAM. A WINTER WEATHER ADVISORY IS IN PLACE FOR SHERIDAN COUNTY 09Z-15Z TONIGHT THROUGH THURSDAY MORNING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 335 AM CDT WED MAY 7 2014 LARGE UPPER LEVEL TROUGH WILL CONTINUE TO SHIFT EAST NORTHEAST ACROSS THE CENTRAL PLAINS ON THURSDAY...REACHING THE NORTHERN MISSOURI VALLEY EARLY FRIDAY. IN THE WAKE OF THE UPPER TROUGH ...QUASI-ZONAL FLOW WILL PREVAIL THROUGH MUCH OF THE WEEKEND...BUT EVENTUALLY BREAK DOWN WITH THE APPROACH OF THE NEXT APPRECIABLE WESTERN STATES UPPER TROUGH. THE SURFACE PATTERN FAVORS A NORTHEASTWARD ADVANCING LOW TOWARD MINNESOTA AND FINALLY INTO SOUTHWEST ONTARIO BY EARLY FRIDAY. THIS LOW WILL DRAG A FRONT THROUGH THE CWA LEAVING POST FRONTAL CONDITIONS INTO EARLY FRIDAY...BUT THE LOWER TROPOSPHERIC FLOW WILL RETURN TO SOUTHERLY AS A LEE TROUGH DEVELOPS OFF THE HIGH PLAINS FRIDAY WITH THE APPROACH OF A WEAK NORTHERN PLAINS UPPER WAVE. THIS WAVE...AS IT/S PREDECESSOR...WILL DRAG AN ADDITIONAL FRONT THROUGH THE CWA ON SATURDAY. THE SATURDAY BAROCLINIC ZONE IS FORECAST TO BE WEAK...WITH LITTLE TO NO SENSIBLE CHANGES ANTICIPATED. FOR THURSDAY...WINTER WEATHER ADVISORY ACROSS SHERIDAN COUNTY WILL CONTINUE UNTIL 15Z. ALL THE MEDIUM RANGE DETERMINISTIC MODELS HAVE CONVERGED SOMEWHAT ON A SOLUTION FOR WHICH THERMAL PROFILES WOULD SUPPORT SNOW ACROSS SHERIDAN COUNTY. THERMAL PROFILES INDICATE A DEEP SATURATION...AT TIMES EXTENDING INTO THE DGZ...BUT WARM GROUND TEMPERATURES AND SFC T/S NEAR OR SLIGHTLY ABOVE 0C CREATE LOW CONFIDENCE FORECAST CONCERNING ACCUMULATIONS. SINCE A STRONG DEFORMATION ZONE IS SHOWN TO SET UP IN THIS AREA...CO-LOCATED IN THE TROWAL REGION OF THE SYSTEM...SNOW RATES MAY BE SUFFICIENT TO OVERCOME THE HIGH SUN ANGLE AND WARM TEMPERATURES...BUT CONFIDENCE IS NOT ENOUGH TO EXPIRE THE ADVISORY BEFORE 15Z. CONSEQUENTLY...GIVEN THE STRENGTH OF THE DEFORMATION...SNOW RATES MAY BE SUFFICIENT TO ALLOW FOR SLUSH ACCUMULATION PAST 15Z THURSDAY. FORECAST TIMING WITH THE CURRENT WINTER WEATHER ADVISORY MAY CHANGE WITH NEAR TERM GUIDANCE. WITH LOW LEVEL CAA ONGOING...HIGH TEMPERATURES THURSDAY WILL BE CHILLY...40S FOR THE NORTHWEST...POSSIBLY SOME 60S SOUTHEAST. WILL NEED TO MONITOR CLOUDS THURSDAY NIGHT AND FRIDAY MORNING AS ANY CLEARING WOULD LEAD TO SUB 0C LOWS...WITH THE THREAT OF A LIGHT FREEZE. ATTM...FAVORING THE ECMWF SOLUTION WHICH IS ON SLOWER SIDE...KEEPING SUFFICIENT CLOUDS ACROSS MUCH OF THE FORECAST AREA TO PREVENT A WIDESPREAD FREEZE. ATTM...NORTHWEST NEBRASKA WOULD HAVE THE HIGHEST POTENTIAL OF SEEING A DAMAGING FREEZE /TO YOUNG PLANTS/...ESPECIALLY IF SNOW TOTALS ARE HIGHER THAN CURRENTLY ANTICIPATED. THE ENTIRE NORTH PLATTE CWA HAS NOT REACHED THE 50 PERCENTILE FOR LAST FREEZE DATE...WE DO NOT PLAN TO FROST/FREEZE HEADLINES ATTM. FRIDAY...WITH RETURN FLOW DIRECTING WAA BACK INTO THE CWA...TEMPERATURES SHOULD WARM BACK WELL INTO THE 60S...POSSIBLY LOWER 70S FOR THE ENTIRE CWA. BUT A FAST MOVING WAVE PASSING THROUGH THE QUASI-ZONAL FLOW MAY SPARK OFF A SHOWER OR TWO DURING THE EVENING AND EARLY ON SATURDAY...WITH A WEAK WIND SHIFT TO FOLLOW. AGAIN SATURDAY TEMPERATURES WON/T BE TOO FAR OFF FROM CLIMO...GENERALLY HIGHS IN THE 60S TO LOWER 70S CAN BE EXPECTED FOR MOST IF NOT ALL LOCATIONS. LATE WEEKEND INTO EARLY NEXT WEEK...ANOTHER SYSTEM LOOKS TO MOVE INTO THE CENTRAL ROCKIES SATURDAY NIGHT AND EMERGE ONTO THE PLAINS SUNDAY AND MONDAY. WIDESPREAD PRECIPITATION WILL BE POSSIBLE...AND DESPITE DIFFERENCES WITH THE HANDLING OF THE SYSTEM...WILL MAINTAIN 30-40 POPS LATE WEEKEND INTO EARLY NEXT WEEK FOR MUCH OF THE CWA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 632 AM CDT WED MAY 7 2014 MVFR/IFR IN SHOWERS AND SEVERE THUNDERSTORMS TODAY...MAINLY NORTH AND WEST OF KOGA-KVTN. VFR IS GENERALLY EXPECTED ELSEWHERE. TONIGHT THIS WEATHER SPREADS EAST TO KIML-KONL. AS THE UPPER LOW...CURRENTLY OVER WRN UT...LIFTS THROUGH WRN NEB LATE TONIGHT...MVFR CIGS SHOULD FILL IN SOUTH OF KVTN-KOGA. NOTE NORTH OF THAT LINE...MVFR/IFR/LOCAL LIFR IN RAIN AND SNOW IS EXPECTED. && .LBF WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM MDT THURSDAY FOR NEZ004. && $$ SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
335 AM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT WED MAY 7 2014 ISOLATED ELEVATED STRONG TO SEVERE THUNDERSTORMS ARE ONGOING THIS MORNING. THE HRRR AND RAP REALLY ARE NOT HANDLING THE STORM TRACK AS THESE METEOROLOGICAL CHALLENGED MODELS PREFER TO TRACK THE ACTIVITY MORE NORTHEAST THROUGH NORTHWEST NEB VS THE WRN SANDHILLS. THIS LIKELY A RESULT OF THE STORM(S) BECOMING ROOTED IN THE LOW LEVEL EASTERLIES. AT ANY RATE THE CURRENT THINKING IS THE STORMS WILL EITHER WEAKEN BEFORE 12Z OR CONTINUE TRACKING TOWARD SCNTL SD. A BLEND OF THE NAM...RAP...ECM...SREF AND THE PREVIOUS FORECAST SUGGESTED SCATTERED POPS THIS MORNING BECOMING LIKELY THIS AFTERNOON. THE RAP HAS ANALYZED A CLOSED H700MB LOW OVER NORTHEAST COLO AT 07Z WHICH LIFTS NORTHEAST THROUGH NWRN NEB THIS MORNING TO FOLLOWED BY A SECOND AND THIRD H7 WAVES THIS AFTERNOON AND EARLY THIS EVENING. THIS WOULD LIKELY KEEP THE WARM SECTOR FROM KIML TO KONL AND SOUTH DRY TODAY. THE NAM SUGGESTS SOME CONVECTION COULD DEVELOP OFF THE FRONT RANGE THIS AFTN AND SWEEP NORTHEAST THROUGH THE SRN AND NERN ZONES. THE THREAT OF SEVERE WEATHER IS OBVIOUS WITH BULK SHEAR 50 KTS OR GREATER AND STEEPENING LAPSE RATES WITH THE APPROACHING 4 CORNERS LOW. SPC HATCHED AN EGG OF VERY LARGE HAIL ACROSS THE WRN SANDHILLS AND PANHANDLE. THIS IS ALONG AND NORTH OF SFC FRONT WHICH IS EXPECTED TO LIFT THROUGH SRN AND NERN NEB LATE THIS AFTN. VERY LARGE HAIL IS POSSIBLE WITH STORMS THIS AFTERNOON AND EVENING AND MOST IF NOT ALL OF THIS SHOULD BE IN THE COLD AIR NORTH OF THE SFC FRONT. THE 5 PERCENT TORNADO AND 15 PERCENT WIND PROBABILITIES WOULD APPEAR CONDITIONALLY TIED TO STORMS FORMING ALONG THE SFC FRONT WHICH LIFTS NORTH OF I-80 AROUND 21Z THIS AFTN AND THEN DROPS BACK SOUTH. SEVERE WEATHER CONTINUES THIS EVENING...PRESUMABLY ELEVATED...WITH THE APPROACH OF THE MAIN UPPER LEVEL LOW. THE NAM AND OTHER MODELS LIFT A DECENT SHOT OF PV15 THROUGH THE FCST AREA. MEANWHILE...LATE SEASON ARCTIC AIR...CURRENTLY IN MONTANA DROPS THROUGH THE HIGH PLAINS FOR A ZONE OF THUNDERSTORMS CHANGING TO WET HEAVY SNOW. THE NAM BACKS THE ELEVATED INSTABILITY RIGHT UP AGAINST THE RAIN SNOW LINE ACROSS SHERIDAN COUNTY AROUND 09Z. THIS MIGHT BE TOO SLOW GIVEN THE PROXIMITY OF THE COLD AIR ACROSS MT AND THE RAIN SNOW LINE OVER NERN WY. THE RAP CAN FIGURE THIS OUT LATER TODAY. FOR NOW THE RAP HAS THE H700MB FREEZING LINE MOVING THROUGH SERN WY AT 00Z THIS EVENING SO A QUICKER CHANGE TO SNOW IS POSSIBLE. THE BEST GUESS ON SNOW AMOUNTS USES THE NAM...GEMREG...SREF AND ECM FOR QPF WITH A 5 OT 1 RATIO FOR UP TO 4 INCHES IN NORTHERN SHERIDAN COUNTY THROUGH 12Z THURSDAY MORING. LOCALLY HIGHER AMOUNTS COULD DEVELOP ESPECIALLY IF THE CHANGE OVER OCCURS AT 06Z VS THE NAM MODEL SHOWING 09Z. THE RAP HAS BEEN THE BEST PERFORMER THIS SPRING IN RAIN SNOW EVENTS FOLLOWED THE NAM. A WINTER WEATHER ADVISORY IS IN PLACE FOR SHERIDAN COUNTY 09Z-15Z TONIGHT THROUGH THURSDAY MORNING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 335 AM CDT WED MAY 7 2014 LARGE UPPER LEVEL TROUGH WILL CONTINUE TO SHIFT EAST NORTHEAST ACROSS THE CENTRAL PLAINS ON THURSDAY...REACHING THE NORTHERN MISSOURI VALLEY EARLY FRIDAY. IN THE WAKE OF THE UPPER TROUGH ...QUASI-ZONAL FLOW WILL PREVAIL THROUGH MUCH OF THE WEEKEND...BUT EVENTUALLY BREAK DOWN WITH THE APPROACH OF THE NEXT APPRECIABLE WESTERN STATES UPPER TROUGH. THE SURFACE PATTERN FAVORS A NORTHEASTWARD ADVANCING LOW TOWARD MINNESOTA AND FINALLY INTO SOUTHWEST ONTARIO BY EARLY FRIDAY. THIS LOW WILL DRAG A FRONT THROUGH THE CWA LEAVING POST FRONTAL CONDITIONS INTO EARLY FRIDAY...BUT THE LOWER TROPOSPHERIC FLOW WILL RETURN TO SOUTHERLY AS A LEE TROUGH DEVELOPS OFF THE HIGH PLAINS FRIDAY WITH THE APPROACH OF A WEAK NORTHERN PLAINS UPPER WAVE. THIS WAVE...AS IT/S PREDECESSOR...WILL DRAG AN ADDITIONAL FRONT THROUGH THE CWA ON SATURDAY. THE SATURDAY BAROCLINIC ZONE IS FORECAST TO BE WEAK...WITH LITTLE TO NO SENSIBLE CHANGES ANTICIPATED. FOR THURSDAY...WINTER WEATHER ADVISORY ACROSS SHERIDAN COUNTY WILL CONTINUE UNTIL 15Z. ALL THE MEDIUM RANGE DETERMINISTIC MODELS HAVE CONVERGED SOMEWHAT ON A SOLUTION FOR WHICH THERMAL PROFILES WOULD SUPPORT SNOW ACROSS SHERIDAN COUNTY. THERMAL PROFILES INDICATE A DEEP SATURATION...AT TIMES EXTENDING INTO THE DGZ...BUT WARM GROUND TEMPERATURES AND SFC T/S NEAR OR SLIGHTLY ABOVE 0C CREATE LOW CONFIDENCE FORECAST CONCERNING ACCUMULATIONS. SINCE A STRONG DEFORMATION ZONE IS SHOWN TO SET UP IN THIS AREA...CO-LOCATED IN THE TROWAL REGION OF THE SYSTEM...SNOW RATES MAY BE SUFFICIENT TO OVERCOME THE HIGH SUN ANGLE AND WARM TEMPERATURES...BUT CONFIDENCE IS NOT ENOUGH TO EXPIRE THE ADVISORY BEFORE 15Z. CONSEQUENTLY...GIVEN THE STRENGTH OF THE DEFORMATION...SNOW RATES MAY BE SUFFICIENT TO ALLOW FOR SLUSH ACCUMULATION PAST 15Z THURSDAY. FORECAST TIMING WITH THE CURRENT WINTER WEATHER ADVISORY MAY CHANGE WITH NEAR TERM GUIDANCE. WITH LOW LEVEL CAA ONGOING...HIGH TEMPERATURES THURSDAY WILL BE CHILLY...40S FOR THE NORTHWEST...POSSIBLY SOME 60S SOUTHEAST. WILL NEED TO MONITOR CLOUDS THURSDAY NIGHT AND FRIDAY MORNING AS ANY CLEARING WOULD LEAD TO SUB 0C LOWS...WITH THE THREAT OF A LIGHT FREEZE. ATTM...FAVORING THE ECMWF SOLUTION WHICH IS ON SLOWER SIDE...KEEPING SUFFICIENT CLOUDS ACROSS MUCH OF THE FORECAST AREA TO PREVENT A WIDESPREAD FREEZE. ATTM...NORTHWEST NEBRASKA WOULD HAVE THE HIGHEST POTENTIAL OF SEEING A DAMAGING FREEZE /TO YOUNG PLANTS/...ESPECIALLY IF SNOW TOTALS ARE HIGHER THAN CURRENTLY ANTICIPATED. THE ENTIRE NORTH PLATTE CWA HAS NOT REACHED THE 50 PERCENTILE FOR LAST FREEZE DATE...WE DO NOT PLAN TO FROST/FREEZE HEADLINES ATTM. FRIDAY...WITH RETURN FLOW DIRECTING WAA BACK INTO THE CWA...TEMPERATURES SHOULD WARM BACK WELL INTO THE 60S...POSSIBLY LOWER 70S FOR THE ENTIRE CWA. BUT A FAST MOVING WAVE PASSING THROUGH THE QUASI-ZONAL FLOW MAY SPARK OFF A SHOWER OR TWO DURING THE EVENING AND EARLY ON SATURDAY...WITH A WEAK WIND SHIFT TO FOLLOW. AGAIN SATURDAY TEMPERATURES WON/T BE TOO FAR OFF FROM CLIMO...GENERALLY HIGHS IN THE 60S TO LOWER 70S CAN BE EXPECTED FOR MOST IF NOT ALL LOCATIONS. LATE WEEKEND INTO EARLY NEXT WEEK...ANOTHER SYSTEM LOOKS TO MOVE INTO THE CENTRAL ROCKIES SATURDAY NIGHT AND EMERGE ONTO THE PLAINS SUNDAY AND MONDAY. WIDESPREAD PRECIPITATION WILL BE POSSIBLE...AND DESPITE DIFFERENCES WITH THE HANDLING OF THE SYSTEM...WILL MAINTAIN 30-40 POPS LATE WEEKEND INTO EARLY NEXT WEEK FOR MUCH OF THE CWA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1224 AM CDT WED MAY 7 2014 ISOLATED THUNDERSTORMS WILL DISSIPATE IN THE OVERNIGHT HOURS ACROSS THE EASTERN NEBRASKA PANHANDLE AND NORTHWESTERN SANDHILLS. ATTM THIS ACTIVITY WILL REMAIN WEST OF THE KLBF AND KVTN TERMINALS. SKIES WILL BE MOSTLY CLOUDY OVERNIGHT WITH CIGS RANGING FROM 15000 TO 20000 FT AGL. AT THE KLBF TERMINAL...SOME LOW CLOUDS MAY DEVELOP OVERNIGHT TONIGHT AS LOW LEVEL MOISTURE PUSHES INTO SOUTHERN AND CENTRAL NEBRASKA FROM THE EAST. CIGS MAY DROP TO AROUND 1000 FT AGL AT THE KLBF TERMINAL AROUND 12Z WEDNESDAY. CIGS WILL LIFT BY LATE MORNING WITH MOSTLY HIGH CLOUDS EXPECTED INTO THE AFTERNOON AND EVENING HOURS. BY 22Z WEDNESDAY...THE THREAT FOR THUNDERSTORMS WILL INCREASE ACROSS SOUTHWESTERN NEBRASKA AND CONTINUE THROUGH LATE EVENING WEDNESDAY. AT THIS TIME...THE THREAT WILL BE FAIRLY LOW AND WILL BE HANDLED WITH A PROB 30 GROUP. FOR THE KVTN TERMINAL...BROKEN CIGS AROUND 15000 FT AGL WILL LOWER TO AROUND 4000 FT AGL BY MID MORNING WEDNESDAY AND PERSIST THROUGH 06Z THURSDAY. THE THREAT FOR THUNDERSTORMS WILL INCREASE AFTER 00Z THURSDAY. WITH SCATTERED COVERAGE EXPECTED AND SOME DOUBT AS TO WHEN THUNDERSTORMS WILL OCCUR...WILL HANDLE THE MENTION WITH A PROB 30 GROUP. && .LBF WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM MDT THURSDAY FOR NEZ004. && $$ SHORT TERM...CDC LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1137 PM CDT TUE MAY 6 2014 .SHORT TERM...(TONIGHT THROUGH FRIDAY) ISSUED AT 305 PM CDT TUE MAY 6 2014 THE MAIN FORECAST CONCERNS IN THE SHORT TERM ARE SMALL PRECIP CHANCES TONIGHT...FIRE WEATHER CONCERNS AND HOW WARM TEMPERATURES WILL GET WEDNESDAY...THEN RAIN CHANCES WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. FIRE WEATHER FORECAST CONCERNS ARE ADDRESSED BELOW. THIS MORNING/S UPPER AIR MAPS SHOWED A MID TROPOSPHERIC TROF OVER THE WEST COAST WITH A RIDGE OVER THE SOUTHEAST U.S. SOUTHWEST FLOW ALOFT WAS TRANSPORTING SOME MID LEVEL MOISTURE INTO THE REGION. WARM...+12C H7 TEMPERATURES WERE NOTED OVER KANSAS. AT H85...THERE WAS SOME POOLING OF HIGHER DEWPOINTS AT OAX...HOWEVER IT WAS FAIRLY DRY AT H85 ACROSS THE PLAINS. THE SURFACE MAP AT 20Z...CONTINUED TO SHOW EAST AND SOUTHEAST FLOW WITH TEMPERATURES IN THE 70S...HOWEVER...THE MID 80 HAD MADE IT INTO FALLS CITY. BASED ON THE SURFACE WINDS AND TEMPERATURES...IT APPEARS THE WARM FRONT HAD LIFTED INTO SOUTHEAST NEBRASKA AND SHOULD BE AROUND LINCOLN. TONIGHT AND WEDNESDAY...THE SURFACE FRONT WILL LIFT NORTH INTO NORTHEAST NEBRASKA AS SURFACE LOW PRESSURE FORMS IN NORTHEAST COLORADO. THE LOW LEVEL JET WILL STRENGTHEN ACROSS EASTERN KANSAS INTO SOUTHEAST NEBRASKA AND THERE IS SOME BROAD SYNOPTIC LIFT ALONG WITH STEEP LAPSE RATES AND WEAK FRONTOGENESIS ALONG WITH SOME WEAK HEIGHT FALLS. THE TRAJECTORY FOR THE BEST PLACEMENT OF PRECIPITATION IS MORE TOWARD CENTRAL IOWA INTO MINNESOTA...HOWEVER SOMETHING ISOLATED MAY TRY TO DEVELOP IN OUR FORECAST AREA...ALONG AND NORTH OF THE WARM FRONT. DEEP MOISTURE APPEARS TO BE A LIMITING FACTOR AND MOST OF THE OPERATIONAL MODELS KEEP THE PRECIP CHANCES ON THE FRINGES OF OUR FORECAST AREA OR OUT OF THE AREA. FORECAST SOUNDINGS SHOW THAT IF SOMETHING HIGH BASED DOES DEVELOP...THERE WOULD BE THE POTENTIAL FOR SOME GUSTY WINDS WITH ANY ISOLATED STORMS. FOR NOW...FAR NORTHEAST NEBRASKA AND WESTERN IOWA IS WHERE OUR ISOLATED THUNDERSTORM CHANCES ARE MENTIONED. THE LATEST RAP IS HINTING AT SOMETHING IN SOUTHEAST NEBRASKA THIS EVENING...SO THIS WILL NEED TO BE WATCHED. WEDNESDAY AFTERNOON...THE VERY DRY AIR OVER PARTS OF SOUTHWEST KANSAS ARE FORECAST TO BE DRAWN NORTHEASTWARD AHEAD OF THE FRONT. THIS COMBINED WITH FAVORABLE MIXING AND SOUTHWEST WINDS SHOULD RESULT IN HOTTER TEMPERATURES IN THE 80S TO LOWER 90S...RESULTING VERY HIGH TO EXTREME FIRE DANGER CONDITIONS. IT DOES NOT LOOK LIKE RECORDS 95/96/99 OMAHA/LINCOLN/NORFOLK... BUT COULD GET CLOSE IF FULL HEATING IS REALIZED. AS DISCUSSED BELOW...DUE TO THE GREENESS...THE RFW WAS LIMITED TO THE AREA THAT HAS BEEN THE DRIEST. WEDNESDAY NIGHT INTO THURSDAY NIGHT...THE MID LEVEL TROF CONTINUE TO MOVE INTO THE PLAINS WITH MOISTURE RICH AIR RETURNING TO EASTERN KANSAS AND A NARROW AREA MAKING IT INTO EASTERN NEBRASKA AND WESTERN IOWA. DO HAVE SCATTERED SHOWERS AND THUNDERSTORMS MENTIONED. THERE IS A SEVERE POTENTIAL WITH THESE STORMS DUE TO THE MODERATE INSTABILITY AND FAVORABLE SHEAR PROFILES. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 PM CDT TUE MAY 6 2014 THERE ARE STILL SOME LARGE MODEL DIFFERENCES. STILL LOOKS LIKE A CHANCE FOR THUNDERSTORMS SATURDAY AND SATURDAY NIGHT. LARGER DIFFERENCES FOR THE REST OF THE WEEKEND INTO EARLY NEXT WEEK. TEMPERATURES STILL LOOK TO MOSTLY BE IN THE 60S AND 70S. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1134 PM CDT TUE MAY 6 2014 VFR CONDITIONS ARE EXPECTED THROUGH THE TAF CYCLE. ADVERTISED LOW LEVEL MOISTURE HAS NOT PRODUCED AN MVFR CLOUD DECK SO HAVE REMOVED ANY MENTION IN TAFS. SOME HAZY CONDITIONS CANNOT BE COMPLETELY RULED OUT IN THE MORNING...HOWEVER CONFIDENCE IN THIS IS FAIRLY LOW SO WILL NOT MENTION IN THE TAFS. A WARM FRONT IN THE AREA WILL CONTINUE TO SLOWLY DRIFT NORTH. SOUTHWEST SFC WINDS WILL INCREASE AT KLNK AND KOMA WED AFTERNOON HOWEVER MAY REMAIN FAIRLY LIGHT OUT OF THE SOUTHEAST AT KOFK. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...RED FLAG WARNING FROM NOON TO 8 PM CDT WEDNESDAY FOR NEZ051-065- 066-078-088-089. IA...NONE. && $$ SHORT TERM...ZAPOTOCNY LONG TERM...ZAPOTOCNY AVIATION...KERN
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1143 PM MDT TUE MAY 6 2014 .AVIATION... 06Z TAF CYCLE WINDS HAVE DIMINISHED ACROSS NORTHERN AND CENTRAL NEW MEXICO THIS EVENING...BUT ARE EXPECTED TO STRENGTHEN AGAIN LATE WEDNESDAY MORNING...REMAINING GUSTY THROUGH EARLY TOMORROW EVENING. SOME SMOKE MAY BE VISIBLE NEAR AND DOWNWIND OR EAST NORTHEAST OF THE JEMEZ MOUNTAINS WHERE PRESCRIBED BURNS HAVE BEEN ONGOING...BUT NO PERCEIVABLE VISIBILITY REDUCTIONS ARE EXPECTED. WINDS WILL BE STRONGEST IN CENTRAL TO EASTERN NEW MEXICO WEDNESDAY AFTERNOON WHERE OCCASIONAL GUSTS WILL APPROACH 40 TO 45 KT. 52 && .PREV DISCUSSION...745 PM MDT TUE MAY 6 2014... .UPDATE... UPDATED FORECAST TO ISSUE A WIND ADVISORY FOR WEDNESDAY FOR MUCH OF CENTRAL...SOUTH CENTRAL AND EASTERN NEW MEXICO. ALSO UPGRADED THE FIRE WEATHER WATCH FOR THE MIDDLE RIO GRANDE VALLEY. TIMING OF THE COLD FRONT WEDNESDAY AROUND MAX HEATING HERE IN THE MIDDLE RIO GRANDE VALLEY LENDING MORE CONFIDENCE TO SEEING AT LEAST A COUPLE HOURS OF WIND ADVISORY SPEEDS...WITH BLOWING DUST LOOKING MORE LIKELY AS WELL. THE WIND ADVISORY EXPIRES AT 8 PM MDT WEDNESDAY... BUT MAY NEED TO BE EXTENDED FOR SOME OF THE EAST CENTRAL AND NORTHEAST PLAINS GIVEN THE TIMING OF THE CORE OF STRONGER WINDS ALOFT AS THE UPPER TROUGH PULLS NE ACROSS NW NEW MEXICO AND INTO COLORADO. 11 && .PREV DISCUSSION...246 PM MDT TUE MAY 6 2014... .SYNOPSIS... THE NEXT STORM SYSTEM APPROACHING NEW MEXICO FROM THE WEST WILL DELIVER ANOTHER PUNCH OF SPRING WINDS AND BLOWING DUST WEDNESDAY. WIDESPREAD DANGEROUS FIRE WEATHER CONDITIONS WILL ACCOMPANY THE WIND AS CONDITIONS ARE EXTREMELY DRY OVER THE AREA. THE WELL ABOVE NORMAL HIGH TEMPERATURES OVER THE PAST SEVERAL DAYS WILL COOL BACK TO BELOW NORMAL FOR THE WEST WEDNESDAY...THEN ALL AREAS THURSDAY AND FRIDAY. A FEW LOCATIONS ACROSS THE NORTHERN AND WESTERN HIGH TERRAIN ALSO HAVE THE POTENTIAL FOR A COUPLE SHOWERS AND THUNDERSTORMS BOTH DAYS. TEMPERATURES WILL REBOUND AGAIN BACK NEAR TO SLIGHTLY ABOVE NORMAL FOR THE WEEKEND WITH WIDESPREAD BREEZY CONDITIONS EXPECTED. && .DISCUSSION... MSAS ANALYSIS SHOWED SURFACE LOW PRESSURE DEEPENED TO 994MB AT 19Z OVER SE COLORADO AND THE 19Z RAP INDICATES THIS WILL CONTINUE TO 989MB BY 00Z. MEANWHILE UPPER LEVEL WINDS ARE INCREASING OVER THE REGION AHEAD OF AN APPROACHING H5 UPPER LOW OVER EAST CENTRAL NV. SURFACE OBS AT KLVS HAVE BEEN NEAR OR JUST ABOVE WIND ADVISORY A COUPLE TIMES BUT SINCE ISOLD IN NATURE WILL NOT ISSUE HIGHLIGHTS. MORE SIGNIFICANT WINDS WILL ARRIVE WEDNESDAY AS THE CORE OF A 40-50KT 700-500MB JET SLIDES OVER CENTRAL/EASTERN NM. WILL PASS ALONG WIND ADVISORY HIGHLIGHTS TO OVERNIGHT CREW. ON THE QPF SIDE OF THINGS THERE ISNT MUCH TO GET EXCITED ABOUT. WPC PROBABILISTIC QPF VALUES FOR 0.10 OR MORE DO SHOW VALUES AROUND 30 PCT OVER SW FACING SLOPES OF THE NW MTS WEDNESDAY. GFS/NAM LIFTED INDICES ARE NEAR -2C FOR TMRW AFTERNOON SO THUNDER POTENTIAL STILL EXISTS. RAISED POPS INTO THE 40 AND 50 PCT RANGE BUT AMOUNTS WILL BE VERY LIGHT. ALSO TOSSED IN DUST FOR THE NW PLATEAU. MAX TEMPS WILL TREND COLDER OVER THE WEST THEN 5 TO 15F BLW NORMAL FOR ALL AREAS THURSDAY. IT WILL FEEL QUITE COOL THURSDAY WITH WIDESPREAD BREEZY CONDITIONS AND ANOTHER ROUND OF SHOWERS/ISOLD STORMS NEAR AND EAST OF HIGH TERRAIN. AGAIN QPF WILL BE VERY LIGHT. FLOW WILL RELAX SLIGHTLY AND BECOME MORE ZONAL WITH WARM ADVECTION THRU THE WEEKEND. GENERALLY CLEAR SKIES ARE EXPECTED MOST AREAS WITH THE EXCEPTION OF HIGH CLOUDS OVER THE NORTH. 700MB TEMPS WILL WARM TO NEAR +12C WHICH IS NEAR THE 75 PERCENTILE FOR MID MAY. THAT WILL TRANSLATE TO HIGHS 5 TO 15F ABV NORMAL AGAIN. MODEL CONSISTENCY AND OUTLOOK FOR NEXT WEEK IS ALMOST COMICAL SO WILL LEAVE THAT FOR LATER. GUYER && .FIRE WEATHER... WIDESPREAD RED FLAG CONDITIONS WILL CONTINUE THROUGH MID EVENING. HAVE UPGRADED ZONES 103 AND 107 TO A RED FLAG WARNING FOR WEDNESDAY LATE MORNING TO EARLY EVENING. WILL LEAVE ZONE 106 AS A WATCH AND LET THE STELLAR NIGHT CREW TAKE ONE MORE LOOK. CHANGE IN THE WEATHER IS ON THE WAY WITH COOLER TEMPERATURES AND EVENTUALLY LESS WIND...THANKS TO A POTENT COLD FRONT TOMORROW AND UPPER LEVEL DISTURBANCE. ONLY MODEST PRECIPITATION CHANCES ACROSS THE NORTH IN THE WEDNESDAY THROUGH THURSDAY TIME PERIOD. WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS TO CONTINUE THROUGH MID EVENING FOR MUCH OF NORTHERN AND CENTRAL NEW MEXICO. WINDS TO SUBSIDE DURING THE NIGHT ASIDE FROM MODERATE BREEZES OVER THE MOUNTAINS AND EAST SLOPES. WINDS WILL INCREASE QUICKLY WEDNESDAY AND BE THE STRONGEST WINDS OF THE WEEK. CRITICAL FIRE WEATHER WILL BE EASILY REACHED OVER MOST CENTRAL AND ALL EASTERN AREAS. HIGH TEMPERATURES WILL BE LOWER EVERYWHERE...BUT STILL ABOVE NORMAL IN THE FAR EAST. THIS WILL BE THE AREA WITH THE LOWEST RH VALUES WITH SINGLE DIGIT READINGS FOR ABOUT 10 HOURS. HAINES VALUES TO BE HIGH TO MODERATE. AREAS TO THE WEST ARE MORE IN THE GREY AREA AS TO HOW TO TREAT THE CRITICAL FIRE WEATHER CONDITIONS. WHILE WINDS WILL BE VERY STRONG AND HUMIDITIES BELOW 15 PERCENT FOR MANY HOURS...THE TEMPERATURES WILL BE NEAR TO BELOW NORMAL IN ZONES 103 AND 107. WITH HAINES VALUES STILL PARTLY IN THE HIGH CATEGORY IN ZONES 103 AND 10 WILL GO AHEAD AND UPGRADE THESE ZONES TO A RED FLAG WARNING FOR WEDNESDAY. WILL LEAVE ZONE 106...MIDDLE RIO GRANDE VALLEY...AS A WATCH. CERTAINLY WINDS AND HUMIDITIES WILL BE CRITICAL FOR SEVERAL HOURS...BUT LOW TO MODERATE HAINES VALUES AND HIGHS SEVERAL DEGREES BELOW NORMAL BRING A MIXED SIGNAL AS TO JUST HOW CRITICAL THIS AREA WILL BE. AS MENTIONED ABOVE WILL LET NIGHT CREW MAKE THE CALL ON ZONE 106. WILL NEED TO FACTOR IN HOW INCREDIBLY DRY IT HAS BEEN LATELY AS WELL. AS FOR CHANCE OF PRECIPITATION...ONLY THE NORTHWEST AND NORTH CENTRAL HIGHER TERRAIN COULD SEE A SHOWER OR THUNDERSTORM WEDNESDAY. MUCH COOLER AIR WILL CONTINUE TO POUR INTO THE STATE WEDNESDAY NIGHT AND THURSDAY. WINDS WILL ALSO FINALLY DIMINISH FOR MOST AREAS. IT WILL STILL BE BREEZY ACROSS THE EAST CENTRAL AREAS. A FEW RAIN AND MOUNTAIN SNOW SHOWERS WILL BE POSSIBLE ACROSS THE WEST AND NORTH BUT NO WETTING PRECIPITATION. FRIDAY SHOULD BE DRY AND MILDER WITH NEAR NORMAL TEMPERATURES AND NOT MUCH WIND. THE WEEKEND SHOULD BE MOSTLY DRY WITH THE WARMING TREND CONTINUING SATURDAY AND LEVELING OFF ON SUNDAY. AN APPROACHING BACK DOOR COLD FRONT COULD TRIGGER A SHOWER IN THE NORTHEAST AND OVER THE NORTHERN MOUNTAINS LATE SUNDAY. THE START OF NEXT WEEK WILL BE COOLER IN THE EAST. IT WILL BE DRY ASIDE FROM A NORTHERN MOUNTAIN SHOWER. THE EUROPEAN MODEL IS MORE BULLISH WITH A TROUGH AND THE PRECIPITATION POTENTIAL FOR EARLY NEXT WEEK. THEN THE GFS GOES BONKERS WITH A STRONG BACK DOOR COLD FRONT BY THE MIDDLE OF NEXT WEEK AND SIGNIFICANT PRECIPITATION IN THE EAST BEHIND THE FRONT. JUST WISHFUL THINKING AT THIS POINT. CHJ && .AVIATION... 18Z TAF CYCLE STORM OVER THE GREAT BASIN TO HEAD SLOWLY EAST. NEAR SFC WINDS STRONGER TODAY THAN MONDAY. SW WIND GUSTS OF 28-30 KTS AT FMN...ABQ...AEG AND SAF. SW WIND GUSTS OF 35-37 KTS OTHER TAF SITES. NO RESTRICTIONS TO VSBY DUE TO DUST IN ANY TAF FORECAST BUT COULD BE SOME MODEST RESTRICTIONS ARE NOT ENTIRELY OUT OF THE QUESTION...MAINLY FOR LVS...TCC AND ROW. OTHERWISE...VFR CONDITIONS ARE FORECAST TO PERSIST. STRONG WINDS AGAIN WED OVER THE E...LOWER SPEEDS IN THE WEST. 40 && .ABQ WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 10 AM TO 8 PM MDT WEDNESDAY FOR THE FOLLOWING ZONES...NMZ103-104-106>108. WIND ADVISORY FROM NOON TO 8 PM MDT WEDNESDAY FOR THE FOLLOWING ZONES...NMZ515-519>540. && $$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
710 PM CDT THU MAY 8 2014 .UPDATE... ISSUED AT 655 PM CDT THU MAY 8 2014 AT 630 PM CDT...SATELLITE LOOPS SHOW HIGH CLOUDS SPREADING OVER SOUTHWEST NORTH DAKOTA REPOPULATING THE CLEAR AREA. H300 CLOSED LOW ON THE RAP MODEL SUGGESTS CIRCULATION AROUND THIS FEATURE IN NORTHEAST WYOMING LIKELY HELPING TO SPREAD THESE HIGH CLOUDS OVER SOUTHWEST ND. MEANWHILE...H500 LOW MIGRATING THROUGH NORTHEAST SOUTH DAKOTA INTO SOUTHEAST NORTH DAKOTA. LIKE THE CURRENT POPS AND WILL NOT CHANGE AT THIS TIME. MAINLY CLOUDS. MAY BE ABLE TO DROP POPS CENTRAL AFTER 9 PM. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 339 PM CDT THU MAY 8 2014 RAINFALL ENDING THIS EVENING AND A DRY FRIDAY WILL HIGHLIGHT THE SHORT TERM. RAINFALL THE REMAINDER OF THE AFTERNOON IS EXPECTED TO REMAIN ALONG AND EAST OF A LINE FROM SELFRIDGE...THROUGH BISMARCK AND HARVEY...SLOWLY DECREASING FROM WEST TO EAST. BASED UPON THE 17-19 UTC RAP/HRRR...RAIN SHOULD FINALLY END ACROSS THE JAMES RIVER VALLEY BY 06-07 UTC. OTHERWISE FOR TONIGHT...A WEAK SURFACE RIDGE AXIS WILL BE IN PLACE ACROSS WESTERN AND CENTRAL NORTH DAKOTA. GIVEN CLEAR SKIES...LIGHT WINDS AND DEW POINTS IN THE UPPER TEENS AND 20S...WIDESPREAD OVERNIGHT LOWS IN THE 20S ARE FORECAST OUTSIDE OF THE JAMES RIVER VALLEY WHERE GREATER CLOUD COVER AND MOISTURE WILL KEEP LOWS IN THE 30S. LEFT THE MENTION OF FOG OUT FOR NOW DUE TO DECEASING LOW LEVEL MOISTURE PROFILES WITH HEIGHT AND THE GREATER LIKELIHOOD OF FROST COMPARED TO FOG. FRIDAY WILL BE CLEAR AND DRY WITH HIGHS IN THE 60S WITH SOUTHERLY FLOW AHEAD OF THE SURFACE LOW ACROSS EASTERN MONTANA. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 339 PM CDT THU MAY 8 2014 AN ACTIVE AND COOL WEATHER PATTERN DEVELOPS FOR THE UPCOMING WEEKEND. UNCERTAINTY INCREASES AFTERWARDS WHEN COMPARING THE LATEST FEW RUNS OF THE GFS AND ECMWF. UPPER LOW/TROUGH OVER THE PACIFIC NORTHWEST DIGS ACROSS THE WESTERN CONUS FRIDAY NIGHT INTO SATURDAY...MOVING OVER THE ROCKIES SUNDAY. 12Z GFS IS MORE PROGRESSIVE AND MOVES THE TROUGH EAST BY MONDAY NIGHT...WHILE THE 00Z/12Z ECMWF LINGERS THE TROUGH THROUGH TUESDAY. NORTHWEST FLOW IS ADVERTISED BY BOTH MODELS BEHIND THE TROUGH...LIKELY ACTIVE WITH EMBEDDED WAVES MOVING THROUGH THE REGION. BASICALLY HAVE CHANCES FOR PRECIPITATION THROUGH THE PERIOD ALONG WITH CONTINUED COOL/BELOW AVERAGE TEMPERATURES. BEST CHANCES FOR PRECIPITATION WILL BE OVER THE WEEKEND AS SFC LOW PRESSURE AND LEAD WAVES MOVE ACROSS THE DAKOTAS. MIX OF RAIN/SNOW POSSIBLE WEST SUNDAY MORNING AS COLDER AIR IS PULLED SOUTH FROM CANADA. ADDITIONAL SNOW POSSIBLE EARLY NEXT WEEK IF THE EUROPEAN`S SOLUTION IS CORRECT WITH A SLOWER EASTWARD PROGRESSION ALLOWING FOR ANOTHER SHOT OF COLD AIR INTO THE REGION. MODELS PORTRAY NO INDICATION OUR COOL AND WET PATTERN WILL CHANGE THROUGH AT LEAST MID-MAY...AND POSSIBLY NOT UNTIL AFTER THE THIRD WEEK OF MAY AT THE EARLIEST. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 655 PM CDT THU MAY 8 2014 HIGH PRESSURE OVER WESTERN NORTH DAKOTA WILL MAINTAIN VFR CONDITIONS ACROSS WESTERN NORTH DAKOTA. SURFACE LOW PRESSURE ACROSS MINNESOTA WILL SPREAD SHOWERS AND MVFR CONDITIONS ACROSS EASTERN NORTH DAKOTA THROUGH THE EVENING. VFR KISN-KDIK-KBIS- KMOT. OCNL MVFR CONDITIONS IN KJMS WILL IMPROVE TO VFR AFTER 08Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...AYD LONG TERM...NH AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
137 PM CDT WED MAY 7 2014 .UPDATE... ISSUED AT 137 PM CDT WED MAY 7 2014 NO SIGNIFICANT CHANGES WITH THIS UPDATE OTHER THAN TO ADJUST POPS FOR THE LATEST RADAR TRENDS THROUGH 1830 UTC...BLENDED TO THE 17 UTC RAP AND THE REMAINING 12 UTC DETERMINISTIC CONSENSUS WHICH SUGGESTS PRECIPITATION DECREASING SIGNIFICANTLY BY 21-00 UTC AND THROUGH THE NIGHT. DID MAINTAIN A MENTION OF SNOW ACROSS THE WEST WITH MULTIPLE LOCATIONS AT LEAST INTERMITTENTLY CONTINUING TO REPORT SNOW. UPDATE ISSUED AT 1026 AM CDT WED MAY 7 2014 UPDATE TO ADD SNOW AND SLEET TO PORTIONS OF NORTHWEST AND NORTH CENTRAL NORTH DAKOTA THIS MORNING FOR LOCATIONS IN THE MID TO UPPER 30S AS OF 1530 UTC. THIS IS BASED UPON MULTIPLE REPORTS BETWEEN WATFORD CITY AND WILLISTON AND THE KEENE AREAS AND DUAL POL SIGNATURES. UPDATE ISSUED AT 826 AM CDT WED MAY 7 2014 QUICK UPDATE TO ADJUST POPS TO THE LATEST OBSERVED TRENDS THROUGH 13 UTC...INCORPORATING THE 11 UTC RAP/HRRR THROUGH THE REMAINDER OF THE AFTERNOON AND EARLY EVENING. ALSO DECREASED CLOUD COVER ACROSS THE NORTHWEST WHERE LOW TO MID LEVEL DECKS ARE THINNING WHICH SHOULD LEAD TO AT LEAST PARTLY SUNNY SKIES. UPDATE ISSUED AT 650 AM CDT WED MAY 7 2014 CURRENT RADAR OBS/TRENDS MATCH THE ONGOING FORECAST. FURTHERMORE...THE LATEST HRRR MATCHES THE LATEST RADAR OBS AND FORECAST TRENDS. WILL CONTINUE TO LEAN HEAVILY ON THE HRRR FOR HOURLY POPS THROUGH THE AFTERNOON. OTHERWISE...THE CURRENT FORECAST IS ON TRACK WITH NO MAJOR UPDATES REQUIRED. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT WED MAY 7 2014 THE LATEST WATER VAPOR CONTINUES TO SHOW A MOIST SOUTHWEST FLOW INTO NORTH DAKOTA WITH MULTIPLE SHORTWAVES AHEAD OF A MAIN UPPER LOW NOW ALONG THE NEVADA/UTAH BORDER. THIS LOW WILL CLOSE OFF AND PIVOT NORTHEAST THROUGH THE SHORT TERM PERIOD...AND WILL BECOME THE MAIN PRECIPITATION PRODUCER OVER SOUTH CENTRAL NORTH DAKOTA LATER WEDNESDAY NIGHT. UNTIL THEN...MODEL GUIDANCE SUGGESTING SEVERAL AREAS OF RAIN SHOWERS WILL MOVE FROM SOUTHWEST TO NORTHEAST TODAY AND THUS FAR LOCAL/REGIONAL RADAR CONFIRMS THIS. OVERALL POPS ARE LIKELY TO CATEGORICAL FOR WESTERN AND MOST OF CENTRAL NORTH DAKOTA TODAY...WITH THE JAMES RIVER VALLEY SEEING HIGHEST POPS LATER THIS AFTERNOON AND AGAIN LATE WEDNESDAY NIGHT. CATEGORICAL POPS HAVE BEEN PAINTED ALONG/NEAR A SURFACE INVERTED TROUGH/BAROCLINIC ZONE...WHICH CURRENTLY STRETCHES FROM SHERWOOD TO MINOT...SOUTH TO CENTER AND INTO MOBRIDGE SOUTH DAKOTA. THIS SURFACE TROUGH WILL SHIFT EAST DURING THE DAY REACHING THE JAMES RIVER VALLEY LATE THIS AFTERNOON. ONCE THIS TROUGH EXITS THE JAMES RIVER VALLEY EARLY THIS EVENING...EXPECT A BRIEF LULL IN THE WIDESPREAD PRECIPITATION...ESSENTIALLY COVERING THE 00Z-06Z THURSDAY TIME FRAME. HOWEVER POPS WILL ONCE AGAIN INCREASE ACROSS THE SOUTH AND SOUTH CENTRAL TOWARD AND AFTER 06Z THURSDAY IN RESPONSE TO THE VERTICAL MOTION FIELD AS THE CLOSED MID LEVEL LOW APPROACHES. HAVE MAINTAINED THE TREND TO KEEP ANY MENTION OF THUNDER SOUTH OF THE BORDER AS INSTABILITY PARAMETERS PER GFS FOLLOW THIS TREND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 324 AM CDT WED MAY 7 2014 AN UPPER LEVEL SHORTWAVE EMANATING FROM THE ROCKIES IS PROGGED TO LIFT NORTH ACROSS THE CENTRAL AND NORTHERN PLAINS THURSDAY. THIS FEATURE SHOULD GENERATE RAIN SHOWERS EXTENDING ALONG AND SOUTH OF A LINE FROM HETTINGER TO BISMARCK TO HARVEY. HOWEVER...HIGH PRESSURE BUILDING INTO EASTERN MONTANA SHOULD KEEP THE FORECAST DRY FOR NORTHWESTERN NORTH DAKOTA. A BREAK IN PRECIP CHANCES IS FORECAST FOR FRIDAY AS HIGH PRESSURE CRESTS ACROSS THE REGION. TEMPERATURES ARE FORECAST TO GET IN THE MID TO UPPER 60S FRIDAY. PRECIPITATION CHANCES RETURN OVER NORTH DAKOTA SATURDAY AS A SHORTWAVE EMANATING FROM THE PACIFIC NORTHWEST TRAVERSES THE NORTHERN PLAINS. THE MEDIUM RANGE MODELS DIVERGE WITH RESPECT TO THE UPPER PATTERN OVER THE CONUS SUNDAY THROUGH THE REMAINDER OF THE PERIOD. THEREFORE...THERE IS QUITE A BIT OF UNCERTAINTY REGARDING THE FORECAST FOR THE FIRST HALF OF NEXT WEEK. EVEN THOUGH A PERSISTENT UPPER LEVEL LOW OVER SASKATCHEWAN IS FORECAST TO MAINTAIN AN UNSETTLED WEATHER REGIME OVER NORTH DAKOTA...THE MODELS HAVE BEEN BACKING OFF ON PRECIP CHANCES/QPF AMOUNTS DUE TO DRY SLOTTING. AS A RESULT...LOWERED POPS TO SLIGHT CHANCE/LOW-END CHANCE SUNDAY AND MONDAY...AND REMOVED POPS FOR MOST OF THE CWA TUESDAY. TEMPERATURES ARE STILL FORECAST TO REMAIN BELOW CLIMO VALUES THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 137 PM CDT WED MAY 7 2014 IFR CONDITIONS AT KDIK AND KMOT IN RAIN...STRATUS AND FOG WILL CONTINUE TO IMPROVE TO MVFR BY LATE THIS AFTERNOON. MVFR CONDITIONS IN RAIN WILL CONTINUE AT KBIS THROUGH 20 UTC AND 22-23 UTC AT KJMS. MVFR CONDITIONS IN STRATUS ARE POSSIBLE AT KBIS/KJMS THEREAFTER. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...KS LONG TERM...TM AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1027 AM CDT WED MAY 7 2014 .UPDATE... ISSUED AT 1026 AM CDT WED MAY 7 2014 UPDATE TO ADD SNOW AND SLEET TO PORTIONS OF NORTHWEST AND NORTH CENTRAL NORTH DAKOTA THIS MORNING FOR LOCATIONS IN THE MID TO UPPER 30S AS OF 1530 UTC. THIS IS BASED UPON MULTIPLE REPORTS BETWEEN WATFORD CITY AND WILLISTON AND THE KEENE AREAS AND DUAL POL SIGNATURES. UPDATE ISSUED AT 826 AM CDT WED MAY 7 2014 QUICK UPDATE TO ADJUST POPS TO THE LATEST OBSERVED TRENDS THROUGH 13 UTC...INCORPORATING THE 11 UTC RAP/HRRR THROUGH THE REMAINDER OF THE AFTERNOON AND EARLY EVENING. ALSO DECREASED CLOUD COVER ACROSS THE NORTHWEST WHERE LOW TO MID LEVEL DECKS ARE THINNING WHICH SHOULD LEAD TO AT LEAST PARTLY SUNNY SKIES. UPDATE ISSUED AT 650 AM CDT WED MAY 7 2014 CURRENT RADAR OBS/TRENDS MATCH THE ONGOING FORECAST. FURTHERMORE...THE LATEST HRRR MATCHES THE LATEST RADAR OBS AND FORECAST TRENDS. WILL CONTINUE TO LEAN HEAVILY ON THE HRRR FOR HOURLY POPS THROUGH THE AFTERNOON. OTHERWISE...THE CURRENT FORECAST IS ON TRACK WITH NO MAJOR UPDATES REQUIRED. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT WED MAY 7 2014 THE LATEST WATER VAPOR CONTINUES TO SHOW A MOIST SOUTHWEST FLOW INTO NORTH DAKOTA WITH MULTIPLE SHORTWAVES AHEAD OF A MAIN UPPER LOW NOW ALONG THE NEVADA/UTAH BORDER. THIS LOW WILL CLOSE OFF AND PIVOT NORTHEAST THROUGH THE SHORT TERM PERIOD...AND WILL BECOME THE MAIN PRECIPITATION PRODUCER OVER SOUTH CENTRAL NORTH DAKOTA LATER WEDNESDAY NIGHT. UNTIL THEN...MODEL GUIDANCE SUGGESTING SEVERAL AREAS OF RAIN SHOWERS WILL MOVE FROM SOUTHWEST TO NORTHEAST TODAY AND THUS FAR LOCAL/REGIONAL RADAR CONFIRMS THIS. OVERALL POPS ARE LIKELY TO CATEGORICAL FOR WESTERN AND MOST OF CENTRAL NORTH DAKOTA TODAY...WITH THE JAMES RIVER VALLEY SEEING HIGHEST POPS LATER THIS AFTERNOON AND AGAIN LATE WEDNESDAY NIGHT. CATEGORICAL POPS HAVE BEEN PAINTED ALONG/NEAR A SURFACE INVERTED TROUGH/BAROCLINIC ZONE...WHICH CURRENTLY STRETCHES FROM SHERWOOD TO MINOT...SOUTH TO CENTER AND INTO MOBRIDGE SOUTH DAKOTA. THIS SURFACE TROUGH WILL SHIFT EAST DURING THE DAY REACHING THE JAMES RIVER VALLEY LATE THIS AFTERNOON. ONCE THIS TROUGH EXITS THE JAMES RIVER VALLEY EARLY THIS EVENING...EXPECT A BRIEF LULL IN THE WIDESPREAD PRECIPITATION...ESSENTIALLY COVERING THE 00Z-06Z THURSDAY TIME FRAME. HOWEVER POPS WILL ONCE AGAIN INCREASE ACROSS THE SOUTH AND SOUTH CENTRAL TOWARD AND AFTER 06Z THURSDAY IN RESPONSE TO THE VERTICAL MOTION FIELD AS THE CLOSED MID LEVEL LOW APPROACHES. HAVE MAINTAINED THE TREND TO KEEP ANY MENTION OF THUNDER SOUTH OF THE BORDER AS INSTABILITY PARAMETERS PER GFS FOLLOW THIS TREND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 324 AM CDT WED MAY 7 2014 AN UPPER LEVEL SHORTWAVE EMANATING FROM THE ROCKIES IS PROGGED TO LIFT NORTH ACROSS THE CENTRAL AND NORTHERN PLAINS THURSDAY. THIS FEATURE SHOULD GENERATE RAIN SHOWERS EXTENDING ALONG AND SOUTH OF A LINE FROM HETTINGER TO BISMARCK TO HARVEY. HOWEVER...HIGH PRESSURE BUILDING INTO EASTERN MONTANA SHOULD KEEP THE FORECAST DRY FOR NORTHWESTERN NORTH DAKOTA. A BREAK IN PRECIP CHANCES IS FORECAST FOR FRIDAY AS HIGH PRESSURE CRESTS ACROSS THE REGION. TEMPERATURES ARE FORECAST TO GET IN THE MID TO UPPER 60S FRIDAY. PRECIPITATION CHANCES RETURN OVER NORTH DAKOTA SATURDAY AS A SHORTWAVE EMANATING FROM THE PACIFIC NORTHWEST TRAVERSES THE NORTHERN PLAINS. THE MEDIUM RANGE MODELS DIVERGE WITH RESPECT TO THE UPPER PATTERN OVER THE CONUS SUNDAY THROUGH THE REMAINDER OF THE PERIOD. THEREFORE...THERE IS QUITE A BIT OF UNCERTAINTY REGARDING THE FORECAST FOR THE FIRST HALF OF NEXT WEEK. EVEN THOUGH A PERSISTENT UPPER LEVEL LOW OVER SASKATCHEWAN IS FORECAST TO MAINTAIN AN UNSETTLED WEATHER REGIME OVER NORTH DAKOTA...THE MODELS HAVE BEEN BACKING OFF ON PRECIP CHANCES/QPF AMOUNTS DUE TO DRY SLOTTING. AS A RESULT...LOWERED POPS TO SLIGHT CHANCE/LOW-END CHANCE SUNDAY AND MONDAY...AND REMOVED POPS FOR MOST OF THE CWA TUESDAY. TEMPERATURES ARE STILL FORECAST TO REMAIN BELOW CLIMO VALUES THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY) ISSUED AT 1026 AM CDT WED MAY 7 2014 IFR/LIFR CONDITIONS AT KDIK AND KMOT IN RAIN...STRATUS AND FOG WILL IMPROVE TO MVFR BY AFTERNOON. MVFR CONDITIONS IN RAIN WILL BEGIN AT KBIS BY 16 UTC...AND CONTINUE THROUGH 19-20 UTC. RAIN WILL APPROACH KJMS BY 18 UTC AND CONTINUE THROUGH 22-23 UTC. MVFR CONDITIONS IN STRATUS ARE POSSIBLE AT KBIS/KJMS THEREAFTER. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...KS LONG TERM...TM AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
826 AM CDT WED MAY 7 2014 .UPDATE... ISSUED AT 826 AM CDT WED MAY 7 2014 QUICK UPDATE TO ADJUST POPS TO THE LATEST OBSERVED TRENDS THROUGH 13 UTC...INCORPORATING THE 11 UTC RAP/HRRR THROUGH THE REMAINDER OF THE AFTERNOON AND EARLY EVENING. ALSO DECREASED CLOUD COVER ACROSS THE NORTHWEST WHERE LOW TO MID LEVEL DECKS ARE THINNING WHICH SHOULD LEAD TO AT LEAST PARTLY SUNNY SKIES. UPDATE ISSUED AT 650 AM CDT WED MAY 7 2014 CURRENT RADAR OBS/TRENDS MATCH THE ONGOING FORECAST. FURTHERMORE...THE LATEST HRRR MATCHES THE LATEST RADAR OBS AND FORECAST TRENDS. WILL CONTINUE TO LEAN HEAVILY ON THE HRRR FOR HOURLY POPS THROUGH THE AFTERNOON. OTHERWISE...THE CURRENT FORECAST IS ON TRACK WITH NO MAJOR UPDATES REQUIRED. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT WED MAY 7 2014 THE LATEST WATER VAPOR CONTINUES TO SHOW A MOIST SOUTHWEST FLOW INTO NORTH DAKOTA WITH MULTIPLE SHORTWAVES AHEAD OF A MAIN UPPER LOW NOW ALONG THE NEVADA/UTAH BORDER. THIS LOW WILL CLOSE OFF AND PIVOT NORTHEAST THROUGH THE SHORT TERM PERIOD...AND WILL BECOME THE MAIN PRECIPITATION PRODUCER OVER SOUTH CENTRAL NORTH DAKOTA LATER WEDNESDAY NIGHT. UNTIL THEN...MODEL GUIDANCE SUGGESTING SEVERAL AREAS OF RAIN SHOWERS WILL MOVE FROM SOUTHWEST TO NORTHEAST TODAY AND THUS FAR LOCAL/REGIONAL RADAR CONFIRMS THIS. OVERALL POPS ARE LIKELY TO CATEGORICAL FOR WESTERN AND MOST OF CENTRAL NORTH DAKOTA TODAY...WITH THE JAMES RIVER VALLEY SEEING HIGHEST POPS LATER THIS AFTERNOON AND AGAIN LATE WEDNESDAY NIGHT. CATEGORICAL POPS HAVE BEEN PAINTED ALONG/NEAR A SURFACE INVERTED TROUGH/BAROCLINIC ZONE...WHICH CURRENTLY STRETCHES FROM SHERWOOD TO MINOT...SOUTH TO CENTER AND INTO MOBRIDGE SOUTH DAKOTA. THIS SURFACE TROUGH WILL SHIFT EAST DURING THE DAY REACHING THE JAMES RIVER VALLEY LATE THIS AFTERNOON. ONCE THIS TROUGH EXITS THE JAMES RIVER VALLEY EARLY THIS EVENING...EXPECT A BRIEF LULL IN THE WIDESPREAD PRECIPITATION...ESSENTIALLY COVERING THE 00Z-06Z THURSDAY TIME FRAME. HOWEVER POPS WILL ONCE AGAIN INCREASE ACROSS THE SOUTH AND SOUTH CENTRAL TOWARD AND AFTER 06Z THURSDAY IN RESPONSE TO THE VERTICAL MOTION FIELD AS THE CLOSED MID LEVEL LOW APPROACHES. HAVE MAINTAINED THE TREND TO KEEP ANY MENTION OF THUNDER SOUTH OF THE BORDER AS INSTABILITY PARAMETERS PER GFS FOLLOW THIS TREND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 324 AM CDT WED MAY 7 2014 AN UPPER LEVEL SHORTWAVE EMANATING FROM THE ROCKIES IS PROGGED TO LIFT NORTH ACROSS THE CENTRAL AND NORTHERN PLAINS THURSDAY. THIS FEATURE SHOULD GENERATE RAIN SHOWERS EXTENDING ALONG AND SOUTH OF A LINE FROM HETTINGER TO BISMARCK TO HARVEY. HOWEVER...HIGH PRESSURE BUILDING INTO EASTERN MONTANA SHOULD KEEP THE FORECAST DRY FOR NORTHWESTERN NORTH DAKOTA. A BREAK IN PRECIP CHANCES IS FORECAST FOR FRIDAY AS HIGH PRESSURE CRESTS ACROSS THE REGION. TEMPERATURES ARE FORECAST TO GET IN THE MID TO UPPER 60S FRIDAY. PRECIPITATION CHANCES RETURN OVER NORTH DAKOTA SATURDAY AS A SHORTWAVE EMANATING FROM THE PACIFIC NORTHWEST TRAVERSES THE NORTHERN PLAINS. THE MEDIUM RANGE MODELS DIVERGE WITH RESPECT TO THE UPPER PATTERN OVER THE CONUS SUNDAY THROUGH THE REMAINDER OF THE PERIOD. THEREFORE...THERE IS QUITE A BIT OF UNCERTAINTY REGARDING THE FORECAST FOR THE FIRST HALF OF NEXT WEEK. EVEN THOUGH A PERSISTENT UPPER LEVEL LOW OVER SASKATCHEWAN IS FORECAST TO MAINTAIN AN UNSETTLED WEATHER REGIME OVER NORTH DAKOTA...THE MODELS HAVE BEEN BACKING OFF ON PRECIP CHANCES/QPF AMOUNTS DUE TO DRY SLOTTING. AS A RESULT...LOWERED POPS TO SLIGHT CHANCE/LOW-END CHANCE SUNDAY AND MONDAY...AND REMOVED POPS FOR MOST OF THE CWA TUESDAY. TEMPERATURES ARE STILL FORECAST TO REMAIN BELOW CLIMO VALUES THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 826 AM CDT WED MAY 7 2014 IFR/LIFR CONDITIONS AT KDIK AND KMOT IN RAIN...STRATUS AND FOG WILL IMPROVE TO MVFR BY AFTERNOON. MVFR CONDITIONS IN RAIN WILL BEGIN AT KBIS BY 16 UTC...AND CONTINUE THROUGH 19-20 UTC. RAIN WILL APPROACH KJMS BY 18 UTC AND CONTINUE THROUGH 22-23 UTC. MVFR CONDITIONS IN STRATUS ARE POSSIBLE AT KBIS/KJMS THEREAFTER. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...KS LONG TERM...TM AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
650 AM CDT WED MAY 7 2014 .UPDATE... ISSUED AT 650 AM CDT WED MAY 7 2014 CURRENT RADAR OBS/TRENDS MATCH THE ONGOING FORECAST. FURTHERMORE...THE LATEST HRRR MATCHES THE LATEST RADAR OBS AND FORECAST TRENDS. WILL CONTINUE TO LEAN HEAVILY ON THE HRRR FOR HOURLY POPS THROUGH THE AFTERNOON. OTHERWISE...THE CURRENT FORECAST IS ON TRACK WITH NO MAJOR UPDATES REQUIRED. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT WED MAY 7 2014 THE LATEST WATER VAPOR CONTINUES TO SHOW A MOIST SOUTHWEST FLOW INTO NORTH DAKOTA WITH MULTIPLE SHORTWAVES AHEAD OF A MAIN UPPER LOW NOW ALONG THE NEVADA/UTAH BORDER. THIS LOW WILL CLOSE OFF AND PIVOT NORTHEAST THROUGH THE SHORT TERM PERIOD...AND WILL BECOME THE MAIN PRECIPITATION PRODUCER OVER SOUTH CENTRAL NORTH DAKOTA LATER WEDNESDAY NIGHT. UNTIL THEN...MODEL GUIDANCE SUGGESTING SEVERAL AREAS OF RAIN SHOWERS WILL MOVE FROM SOUTHWEST TO NORTHEAST TODAY AND THUS FAR LOCAL/REGIONAL RADAR CONFIRMS THIS. OVERALL POPS ARE LIKELY TO CATEGORICAL FOR WESTERN AND MOST OF CENTRAL NORTH DAKOTA TODAY...WITH THE JAMES RIVER VALLEY SEEING HIGHEST POPS LATER THIS AFTERNOON AND AGAIN LATE WEDNESDAY NIGHT. CATEGORICAL POPS HAVE BEEN PAINTED ALONG/NEAR A SURFACE INVERTED TROUGH/BAROCLINIC ZONE...WHICH CURRENTLY STRETCHES FROM SHERWOOD TO MINOT...SOUTH TO CENTER AND INTO MOBRIDGE SOUTH DAKOTA. THIS SURFACE TROUGH WILL SHIFT EAST DURING THE DAY REACHING THE JAMES RIVER VALLEY LATE THIS AFTERNOON. ONCE THIS TROUGH EXITS THE JAMES RIVER VALLEY EARLY THIS EVENING...EXPECT A BRIEF LULL IN THE WIDESPREAD PRECIPITATION...ESSENTIALLY COVERING THE 00Z-06Z THURSDAY TIME FRAME. HOWEVER POPS WILL ONCE AGAIN INCREASE ACROSS THE SOUTH AND SOUTH CENTRAL TOWARD AND AFTER 06Z THURSDAY IN RESPONSE TO THE VERTICAL MOTION FIELD AS THE CLOSED MID LEVEL LOW APPROACHES. HAVE MAINTAINED THE TREND TO KEEP ANY MENTION OF THUNDER SOUTH OF THE BORDER AS INSTABILITY PARAMETERS PER GFS FOLLOW THIS TREND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 324 AM CDT WED MAY 7 2014 AN UPPER LEVEL SHORTWAVE EMANATING FROM THE ROCKIES IS PROGGED TO LIFT NORTH ACROSS THE CENTRAL AND NORTHERN PLAINS THURSDAY. THIS FEATURE SHOULD GENERATE RAIN SHOWERS EXTENDING ALONG AND SOUTH OF A LINE FROM HETTINGER TO BISMARCK TO HARVEY. HOWEVER...HIGH PRESSURE BUILDING INTO EASTERN MONTANA SHOULD KEEP THE FORECAST DRY FOR NORTHWESTERN NORTH DAKOTA. A BREAK IN PRECIP CHANCES IS FORECAST FOR FRIDAY AS HIGH PRESSURE CRESTS ACROSS THE REGION. TEMPERATURES ARE FORECAST TO GET IN THE MID TO UPPER 60S FRIDAY. PRECIPITATION CHANCES RETURN OVER NORTH DAKOTA SATURDAY AS A SHORTWAVE EMANATING FROM THE PACIFIC NORTHWEST TRAVERSES THE NORTHERN PLAINS. THE MEDIUM RANGE MODELS DIVERGE WITH RESPECT TO THE UPPER PATTERN OVER THE CONUS SUNDAY THROUGH THE REMAINDER OF THE PERIOD. THEREFORE...THERE IS QUITE A BIT OF UNCERTAINTY REGARDING THE FORECAST FOR THE FIRST HALF OF NEXT WEEK. EVEN THOUGH A PERSISTENT UPPER LEVEL LOW OVER SASKATCHEWAN IS FORECAST TO MAINTAIN AN UNSETTLED WEATHER REGIME OVER NORTH DAKOTA...THE MODELS HAVE BEEN BACKING OFF ON PRECIP CHANCES/QPF AMOUNTS DUE TO DRY SLOTTING. AS A RESULT...LOWERED POPS TO SLIGHT CHANCE/LOW-END CHANCE SUNDAY AND MONDAY...AND REMOVED POPS FOR MOST OF THE CWA TUESDAY. TEMPERATURES ARE STILL FORECAST TO REMAIN BELOW CLIMO VALUES THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 650 AM CDT WED MAY 7 2014 WIDESPREAD RAIN SHOWERS WILL CONTINUE RESULTING IN IFR CIGS AND MVFR VSBYS AT KDIK/KMOT THROUGH EARLY WEDNESDAY EVENING. ALTHOUGH KISN WILL BEGIN WITH BORDERLINE IFR CIGS...EXPECT PRECIPITATION TO END WITH CIGS IMPROVING TO VFR BY 15Z WEDNESDAY. AT KBIS...CIGS WILL DETERIORATE TO MVFR BY 16Z WEDNESDAY AND REMAIN THERE THROUGH 12Z THURSDAY. KJMS WILL REMAIN VFR THROUGH WEDNESDAY EVENING...THEN IFR CIGS AND MVFR VSBYS TAKE CONTROL BY 09Z THURSDAY. NORTHERLY WINDS OF 15KT TO 25KT WILL SPREAD FROM WEST TO EAST THROUGH THE TAF PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...KS LONG TERM...TM AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1150 PM CDT TUE MAY 6 2014 .UPDATE... ISSUED AT 1150 PM CDT TUE MAY 6 2014 LOCAL/REGIONAL RADARS SHOWING AN AREA OF RAIN SHOWERS IN WESTERN SOUTH DAKOTA HEADING NORTHEAST WITH TIME. THE HRRR MODEL CAPTURES THIS AREA THE BEST AND SHIFTS IT INTO SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA OVERNIGHT INTO MID MORNING WEDNESDAY. HAVE USED THIS FOR THE POPS/PRECIPITATION FORECAST. STILL APPEARS THAT THE WEST WILL REMAIN UNDER THE HIGHEST POPS FOR THE REST OF TUESDAY NIGHT AND A PORTION OF WEDNESDAY...BEFORE THE MAIN SURGE OF SHOWERS SHIFTS INTO CENTRAL NORTH DAKOTA WEDNESDAY NIGHT IN TANDEM WITH APPROACH OF A MID LEVEL CLOSED CIRCULATION. CURRENT FORECAST HAS THE NEAR TERM HANDLED WELL AND ONLY MINOR TWEAKS TO CURRENT POPS/WEATHER. UPDATE ISSUED AT 950 PM CDT TUE MAY 6 2014 LATEST RADAR IMAGERY SHOWS ISOLATED SHOWERS LIFTING NORTHEAST ACROSS CENTRAL NORTH DAKOTA. MAIN SHOWER ACTIVITY REMAINS OVER EASTERN MONTANA...WITH ANOTHER AREA OF SHOWERS LIFTING NORTHEAST ACROSS FAR SOUTHEAST MONTANA INTO NORTHWEST SOUTH DAKOTA. HAVE MADE SOME POP ADJUSTMENTS...KEEPING MAINLY SLIGHT CHANCE TO CHANCE POPS THIS EVENING...AND THEN BRINGING HIGHER POPS FROM WEST TO EAST LATE TONIGHT. CONVECTION HAS ENDED IN THE NORTHWEST AND THINK THE CONVECTION OVER NORTHEAST WYOMING WILL HAVE A HARD TIME MAINTAINING ITSELF AS IT MOVES CLOSER TO NORTH DAKOTA LATE THIS EVENING. OTHERWISE NO SIGNIFICANT CHANGES TO THE GOING FORECAST. UPDATE ISSUED AT 617 PM CDT TUE MAY 6 2014 UPDATE MAINLY TO BRING A MENTION OF SHOWERS AND THUNDER TO THE NORTHWEST EARLY THIS EVENING. CONVERGENCE ALONG A WEAKENING COLD FRONT MOVING INTO THE WESTERN DAKOTAS COMBINED WITH WEAK LOW LEVEL INSTABILITY AND MODERATE SHEAR MOVING IN FROM THE WEST HAS RESULTED IN AN AREA OF SHOWERS AND ONE THUNDERSTORM CELL THAT IS CURRENTLY MOVING INTO THE FAR NORTHWEST. ISSUED A NOWCAST WITH A MENTION OF SMALL HAIL...AFFECTING SOUTHWEST DIVIDE AND NORTHWEST WILLIAMS...INCLUDING GRENORA. BUMPED UP POPS IN THE FAR NORTHWEST THROUGH WEST CENTRAL EARLY THIS EVENING...AND LOWERED POPS ACROSS THE CENTRAL...WITH ONLY SOME ISOLATED SHOWER ACTIVITY FROM BOWMAN NORTHEAST THROUGH BISMARCK TO THE CARRINGTON AREA. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 328 PM CDT TUE MAY 6 2014 PRECIPITATION POTENTIAL WILL HIGHLIGHT THE SHORT TERM FORECAST. THINNING CLOUD COVER ACROSS NORTHWEST AND MUCH OF SOUTH CENTRAL AND SOUTHEAST NORTH DAKOTA MAY LEAD TO ISOLATED TO SCATTERED SHOWER DEVELOPMENT LATE THIS AFTERNOON AND INTO THE EARLY EVENING WITH SUFFICIENT SURFACE DESTABILIZATION. THE FAR SOUTH CENTRAL NEAR THE SOUTH DAKOTA BORDER AND NORTHWEST NORTH DAKOTA DO HAVE THE POTENTIAL FOR THUNDERSTORMS WHERE MID LEVEL LAPSE RATES ARE STEEPEST. AFTER SUNSET...RAIN SHOWER ACTIVITY IS EXPECTED TO DECREASE IN COVERAGE UNTIL THE 06-08 UTC TIME FRAME WHEN PRECIPITATION INCREASES ACROSS THE WEST WHEN THE BROADER AREA OF PRECIPITATION ACROSS SOUTH CENTRAL THROUGH NORTHEAST MONTANA AS OF 20 UTC PROPAGATES EAST. WIDESPREAD RAIN SHOWER ACTIVITY WILL CONTINUE THROUGHOUT WEDNESDAY ACROSS THE CENTRAL AND SOUTHWEST...WITH A POTENTIAL DECREASE IN RAINFALL ACTIVITY NORTHWEST AS THE WEAKENING SURFACE HIGH PROPAGATES IN. FINALLY...DID ADD A MENTION OF PATCHY FOG TO MOST AREAS WITH STRATUS BUILD DOWN TONIGHT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 328 PM CDT TUE MAY 6 2014 A PERSISTENT UPPER LEVEL LOW OVER NORTHERN SASKATCHEWAN WILL GENERATE AN UNSETTLED WEATHER PATTERN OVER NORTH DAKOTA THROUGH THE EXTENDED. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...THE AFOREMENTIONED LOW COMBINED WITH A LONGWAVE TROUGH OVER THE ROCKIES WILL CONTRIBUTE TO PERSISTENT RAIN SHOWER CHANCES OVER WESTERN AND CENTRAL NORTH DAKOTA WEDNESDAY NIGHT...AND IN CENTRAL AND SOUTHWESTERN NORTH DAKOTA ON THURSDAY...AND SOUTH CENTRAL NORTH DAKOTA THURSDAY NIGHT. THE MODEL CONSENSUS CONTINUES TO INDICATE THE HIGHEST RAINFALL AMOUNTS OVER SOUTH CENTRAL NORTH DAKOTA...WITH AREAS ALONG AND SOUTHEAST OF A LINE FROM SIOUX AND GRANT COUNTY TO BISMARCK/MANDAN TO CARRINGTON RECEIVING ANYWHERE FROM 1/2 INCH TO NEARLY 1 INCH IN THIS 36-HOUR PERIOD. PRECIPITATION TOTALS FROM TUESDAY NIGHT THROUGH THURSDAY NIGHT...AREAS ALONG AND SOUTHEAST OF A BOWMAN TO DICKINSON...TO GARRISON TO RUGBY MAY EXPECT ANYWHERE FROM 1/2 INCH TO 1 1/4 INCHES OF PRECIPITATION. A BREAK IN PRECIP CHANCES IS FORECAST FOR FRIDAY AS A WEAK SHORTWAVE RIDGE SNEAKS UNDER THE PERSISTENT SASKATCHEWAN LOW. TEMPERATURES ARE EXPECTED TO REACH INTO THE 60S FRIDAY. THE SASKATCHEWAN LOW IS THEN PROGGED TO USHER IN SHORTWAVE AFTER SHORTWAVE OVER NORTH DAKOTA THROUGH THE REMAINDER OF THE EXTENDED. DUE TO TIMING/INTENSITY UNCERTAINTIES...BROADBRUSHED CHANCE POPS OVER THE FORECAST AREA SATURDAY THROUGH TUESDAY. TEMPERATURES WILL LIKELY REMAIN BELOW NORMAL...MAINLY HIGHS IN THE 50S...WITH THE UNSETTLED WEATHER PATTERN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1150 PM CDT TUE MAY 6 2014 AN AREA OF IFR CIGS WILL EXPAND ACROSS THE WEST THROUGH 12Z IMPACTING KISN/KDIK. IN COMBINATION WITH THE LOWERING CIGS WEST WILL BE AN AREA OF RAIN SHOWERS MOVING NORTHEAST FROM WESTERN SOUTH DAKOTA. THIS WILL SLIDE INTO KDIK AND KBIS BEFORE 12Z WEDNESDAY. LIGHT RAIN SHOWERS WILL CONTINUE AT KISN AS MOISTURE IS REPLENISHED IN EASTERN MONTANA AND MOVING NORTHEAST WITH TIME. IFR CIGS AND MVFR VSBYS CAN BE EXPECTED AT KMOT/KDIK FROM AROUND 12Z TUESDAY THROUGH 06Z WEDNESDAY. MVFR CIGS ARE FORECAST FOR KBIS. KJMS WILL REMAIN VFR UNTIL 03Z WEDNESDAY...AS THE BULK OF THE STEADY RAIN SHOWERS ARRIVE AFTER 06Z THURSDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...AYD LONG TERM...JV AVIATION...KS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
652 AM EDT WED MAY 7 2014 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH THROUGH THE OHIO VALLEY TODAY...ALLOWING FOR TEMPERATURES WELL ABOVE NORMAL TODAY AND THURSDAY. SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE AREA ON FRIDAY AND SATURDAY...AS A COLD FRONT SLOWLY MOVES EAST THROUGH THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A RATHER HEALTHY BAND OF CONVECTION HAS DEVELOPED IN SOUTHERN MICHIGAN AND NORTHWESTERN OHIO...ALONG AN AXIS GENERALLY PARALLEL TO (BUT A COUPLE HUNDRED MILES REMOVED FROM) THE SURFACE WARM FRONT. OBVIOUSLY ELEVATED IN NATURE...THIS CONVECTION IS ON A TRAJECTORY TO MISS THE ILN FORECAST AREA ENTIRELY. JUST A SLIGHT CHANCE OF A SHOWER HAS BEEN KEPT IN THE FAR NORTHERN/NORTHEASTERN ILN COUNTIES FOR A FEW HOURS. RIDGING IS ALREADY BUILDING INTO THE FORECAST AREA...WITH 925MB TEMPERATURES ALREADY BEGINNING TO RISE. THE ACTUAL SURFACE WARM FRONT WILL CROSS THE CWA FROM SOUTH TO NORTH BETWEEN EARLY THIS MORNING AND AROUND 18Z...SHIFTING FLOW TO THE SOUTHWEST THROUGH THE COLUMN...SETTING UP A FAVORABLE WARM ADVECTION PATTERN. ALL SIGNS POINT TO A WELL MIXED BOUNDARY LAYER TODAY...WHICH SHOULD ALLOW FOR A SIGNIFICANT WARMING IN TEMPERATURES TO THE LOWER TO MID 80S...AS WELL AS WIND GUSTS INTO THE 20-30 MPH RANGE. RECORD HIGHS FOR TODAY (MAY 7) APPEAR TO BE SAFE. CMH: 87 / 1936 DAY: 87 / 1926 AND 1897 CVG: 89 / 1940 ONLY THE RAP (WITH ITS OVER-MIXED BOUNDARY LAYER TENDENCIES) HAD VALUES ANYWHERE NEAR THOSE NUMBERS. THIS FORECAST WILL STAY A FEW DEGREES BELOW THE RAP...BUT ON THE HIGHER SIDE OF THE REST OF THE GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... CONTINUED SOUTHWESTERLY FLOW WILL LEAD TO MILD CONDITIONS TONIGHT...BEFORE ANOTHER VERY WARM DAY IS EXPECTED ON THURSDAY. THE OVERALL WEATHER PATTERN WILL BE CHANGING VERY LITTLE...WITH MID-LEVEL RIDGING OVER THE OHIO VALLEY (EXTENDING FROM THE SOUTHEASTERN STATES). ANOTHER WELL-MIXED DAY WITH APPRECIABLE AMOUNTS OF SUN WILL LEAD TO SIMILAR TEMPERATURES TO WEDNESDAY...PERHAPS EVEN A FEW DEGREES WARMER. RECORD HIGHS FOR ALL THREE CLIMATE SITES ARE 89 DEGREES FOR MAY 8...AND AGAIN AS ON WEDNESDAY...THESE LOOK TO BE SAFE. GOING INTO FRIDAY...A BROAD UPPER TROUGH WILL BE MOVING NORTHEAST FROM THE PLAINS INTO CANADA...WITH A SURFACE LOW FORECAST TO RIDE ALONG THE TROUGH THROUGH MINNESOTA AND INTO NORTHERN ONTARIO. A COLD FRONT WILL EXTEND FROM SOUTH OF THIS LOW AND WILL MOVE INTO THE OHIO VALLEY ON FRIDAY. WITH THE LOW SO FAR AWAY FROM THE REGION...AND THE MID-LEVEL FLOW FAILING TO BECOME PARTICULARLY SHARP...THERE IS LITTLE IMPETUS FOR THE FRONT TO MAINTAIN ITS STRENGTH AS IT LUMBERS EASTWARD. THIS SETS UP FORECAST WITH SPECIFICS THAT REMAIN RATHER UNCERTAIN...WITH CONCERNS OF TIMING AND FORCING STRENGTH PRECLUDING ANY HIGHER THAN 70-PERCENT POPS DURING THE SPAN FROM FRIDAY THROUGH SATURDAY (EVEN THOUGH IT IS VERY LIKELY THAT THE ENTIRE CWA WILL GET SOME RAIN OUT OF THIS SYSTEM). THE FIRST WAVE AHEAD OF THE FRONT (MOVING INTO THE ILN CWA ON FRIDAY MORNING) APPEARS TO FALL APART AS IT GETS TOO FAR AHEAD OF THE SURFACE TROUGH...AND THE BIGGEST QUESTION WITH THE SECOND WAVE IS THE TIMING (WITH A FEW MODELS NOW SHOWING THIS MORE AS A FRIDAY NIGHT ISSUE THAN A SATURDAY ONE). WITH QUESTIONABLE LOW-LEVEL MOISTURE ON FRIDAY (LIMITING INSTABILITY)...AND THE WEAK FORCING AND SLOW FRONTAL MOTION ALSO FACTORED IN...THE THREAT FOR STRONG STORMS APPEARS RATHER LOW. THE PLACEMENT OF THE SECOND WAVE WILL END UP DETERMINING IF ANY CHANCE FOR HEAVY OR PROLONGED RAIN MIGHT LEAD TO A POSSIBILITY OF FLOODING...BUT THIS ALSO APPEARS TO BE A LOW-END THREAT. TEMPERATURES WILL ALSO BE HELD DOWN BY THE OCCASIONAL RAIN AND PERSISTENT CLOUD COVER...WITH A GRADIENT FROM THE MID 70S (NW CWA) TO NEAR 80 (SE CWA) ON FRIDAY...THEN NEAR 70 DEGREES EXPECTED ON SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... MODEL SOLUTIONS DIVERGE THEREAFTER. ELECTED TO GO CLOSER TO THE ECMWF WHICH...AFTER AN INTERLUDE OF SOMEWHAT DRIER CONDITIONS ON SUNDAY AND MONDAY...BRINGS THE NEXT COLD FRONT CONTAINING A CHANCE OF THUNDERSTORMS ON TUESDAY. EXPECT HIGH TEMPERATURES PRIMARILY IN THE 70S. THE EXCEPTION MAY BE ON MONDAY...WHEN WARM ADVECTION MAY PUSH READINGS INTO THE LOWER 80S. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... A MID LEVEL RIDGE WILL BUILD NORTH INTO THE SOUTHERN GREAT LAKES TODAY. AS THIS OCCURS...A WARM FRONT WILL LIFT NORTH ACROSS THE REGION THIS MORNING. FOR THIS AFTERNOON...REGION WILL BE LOCATED IN THE WARM SECTOR. DAYTIME MIXING WILL RESULT IN SOUTHERLY WINDS IN THE 10 TO 15 KNOT RANGE WITH GUSTS GENERALLY IN THE 20 TO 25 KNOT RANGE. MAINLY HIGH LEVEL CLOUDS WILL THIN SOME BY AFTERNOON. FOR TONIGHT...MID LEVEL RIDGE WILL REMAIN IN PLACE WITH MOSTLY CLEAR SKIES EXPECTED. OUTLOOK...THUNDERSTORMS POSSIBLE FRIDAY INTO SUNDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
418 AM EDT WED MAY 7 2014 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH THROUGH THE OHIO VALLEY TODAY...ALLOWING FOR TEMPERATURES WELL ABOVE NORMAL TODAY AND THURSDAY. SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE AREA ON FRIDAY AND SATURDAY...AS A COLD FRONT SLOWLY MOVES EAST THROUGH THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A RATHER HEALTHY BAND OF CONVECTION HAS DEVELOPED IN SOUTHERN MICHIGAN AND NORTHWESTERN OHIO...ALONG AN AXIS GENERALLY PARALLEL TO (BUT A COUPLE HUNDRED MILES REMOVED FROM) THE SURFACE WARM FRONT. OBVIOUSLY ELEVATED IN NATURE...THIS CONVECTION IS ON A TRAJECTORY TO MISS THE ILN FORECAST AREA ENTIRELY. JUST A SLIGHT CHANCE OF A SHOWER HAS BEEN KEPT IN THE FAR NORTHERN/NORTHEASTERN ILN COUNTIES FOR A FEW HOURS. RIDGING IS ALREADY BUILDING INTO THE FORECAST AREA...WITH 925MB TEMPERATURES ALREADY BEGINNING TO RISE. THE ACTUAL SURFACE WARM FRONT WILL CROSS THE CWA FROM SOUTH TO NORTH BETWEEN EARLY THIS MORNING AND AROUND 18Z...SHIFTING FLOW TO THE SOUTHWEST THROUGH THE COLUMN...SETTING UP A FAVORABLE WARM ADVECTION PATTERN. ALL SIGNS POINT TO A WELL MIXED BOUNDARY LAYER TODAY...WHICH SHOULD ALLOW FOR A SIGNIFICANT WARMING IN TEMPERATURES TO THE LOWER TO MID 80S...AS WELL AS WIND GUSTS INTO THE 20-30 MPH RANGE. RECORD HIGHS FOR TODAY (MAY 7) APPEAR TO BE SAFE. CMH: 87 / 1936 DAY: 87 / 1926 AND 1897 CVG: 89 / 1940 ONLY THE RAP (WITH ITS OVER-MIXED BOUNDARY LAYER TENDENCIES) HAD VALUES ANYWHERE NEAR THOSE NUMBERS. THIS FORECAST WILL STAY A FEW DEGREES BELOW THE RAP...BUT ON THE HIGHER SIDE OF THE REST OF THE GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... CONTINUED SOUTHWESTERLY FLOW WILL LEAD TO MILD CONDITIONS TONIGHT...BEFORE ANOTHER VERY WARM DAY IS EXPECTED ON THURSDAY. THE OVERALL WEATHER PATTERN WILL BE CHANGING VERY LITTLE...WITH MID-LEVEL RIDGING OVER THE OHIO VALLEY (EXTENDING FROM THE SOUTHEASTERN STATES). ANOTHER WELL-MIXED DAY WITH APPRECIABLE AMOUNTS OF SUN WILL LEAD TO SIMILAR TEMPERATURES TO WEDNESDAY...PERHAPS EVEN A FEW DEGREES WARMER. RECORD HIGHS FOR ALL THREE CLIMATE SITES ARE 89 DEGREES FOR MAY 8...AND AGAIN AS ON WEDNESDAY...THESE LOOK TO BE SAFE. GOING INTO FRIDAY...A BROAD UPPER TROUGH WILL BE MOVING NORTHEAST FROM THE PLAINS INTO CANADA...WITH A SURFACE LOW FORECAST TO RIDE ALONG THE TROUGH THROUGH MINNESOTA AND INTO NORTHERN ONTARIO. A COLD FRONT WILL EXTEND FROM SOUTH OF THIS LOW AND WILL MOVE INTO THE OHIO VALLEY ON FRIDAY. WITH THE LOW SO FAR AWAY FROM THE REGION...AND THE MID-LEVEL FLOW FAILING TO BECOME PARTICULARLY SHARP...THERE IS LITTLE IMPETUS FOR THE FRONT TO MAINTAIN ITS STRENGTH AS IT LUMBERS EASTWARD. THIS SETS UP FORECAST WITH SPECIFICS THAT REMAIN RATHER UNCERTAIN...WITH CONCERNS OF TIMING AND FORCING STRENGTH PRECLUDING ANY HIGHER THAN 70-PERCENT POPS DURING THE SPAN FROM FRIDAY THROUGH SATURDAY (EVEN THOUGH IT IS VERY LIKELY THAT THE ENTIRE CWA WILL GET SOME RAIN OUT OF THIS SYSTEM). THE FIRST WAVE AHEAD OF THE FRONT (MOVING INTO THE ILN CWA ON FRIDAY MORNING) APPEARS TO FALL APART AS IT GETS TOO FAR AHEAD OF THE SURFACE TROUGH...AND THE BIGGEST QUESTION WITH THE SECOND WAVE IS THE TIMING (WITH A FEW MODELS NOW SHOWING THIS MORE AS A FRIDAY NIGHT ISSUE THAN A SATURDAY ONE). WITH QUESTIONABLE LOW-LEVEL MOISTURE ON FRIDAY (LIMITING INSTABILITY)...AND THE WEAK FORCING AND SLOW FRONTAL MOTION ALSO FACTORED IN...THE THREAT FOR STRONG STORMS APPEARS RATHER LOW. THE PLACEMENT OF THE SECOND WAVE WILL END UP DETERMINING IF ANY CHANCE FOR HEAVY OR PROLONGED RAIN MIGHT LEAD TO A POSSIBILITY OF FLOODING...BUT THIS ALSO APPEARS TO BE A LOW-END THREAT. TEMPERATURES WILL ALSO BE HELD DOWN BY THE OCCASIONAL RAIN AND PERSISTENT CLOUD COVER...WITH A GRADIENT FROM THE MID 70S (NW CWA) TO NEAR 80 (SE CWA) ON FRIDAY...THEN NEAR 70 DEGREES EXPECTED ON SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... MODEL SOLUTIONS DIVERGE THEREAFTER. ELECTED TO GO CLOSER TO THE ECMWF WHICH...AFTER AN INTERLUDE OF SOMEWHAT DRIER CONDITIONS ON SUNDAY AND MONDAY...BRINGS THE NEXT COLD FRONT CONTAINING A CHANCE OF THUNDERSTORMS ON TUESDAY. EXPECT HIGH TEMPERATURES PRIMARILY IN THE 70S. THE EXCEPTION MAY BE ON MONDAY...WHEN WARM ADVECTION MAY PUSH READINGS INTO THE LOWER 80S. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... A MID LEVEL RIDGE WILL BUILD NORTH INTO THE SOUTHERN GREAT LAKES TODAY. AS THIS OCCURS...A WARM FRONT WILL LIFT NORTH ACROSS THE REGION THIS MORNING. THERE MAY BE ENOUGH LIFT/ASCENT AHEAD OF THE FRONT FOR AN ISOLATED SHOWER/THUNDERSTORM NEAR THE KCMH/KLCK TERMINALS. GIVEN THE LOW PROBABILITY...THE TAFS WILL BE KEPT DRY. FOR THIS AFTERNOON...REGION WILL BE LOCATED IN THE WARM SECTOR. DAYTIME MIXING WILL RESULT IN SOUTHERLY WINDS IN THE 10 TO 15 KNOT RANGE WITH GUSTS GENERALLY IN THE 20 TO 25 KNOT RANGE. MAINLY HIGH LEVEL CLOUDS WILL THIN SOME BY AFTERNOON. FOR TONIGHT...MID LEVEL RIDGE WILL REMAIN IN PLACE WITH MOSTLY CLEAR SKIES EXPECTED. OUTLOOK...THUNDERSTORMS POSSIBLE FRIDAY INTO SUNDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1033 PM CDT THU MAY 8 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 441 PM CDT THU MAY 8 2014 CURRENT SURFACE ANALYSIS INDICATING THE SURFACE LOW PRESSURE CENTER LOCATED OVER NORTHEASTERN NEBRASKA INTO NORTHWESTERN IOWA...WITH A WARM FRONT EXTENDING EASTWARD TO JUST SOUTH OF WORTHINGTON AND JACKSON MINNESOTA. EARLIER ROUND OF CONVECTION STABILIZED THE ATMOSPHERE A BIT...BUT WITH BREAKS IN THE CLOUD COVER THROUGH THE AFTERNOON...INSTABILITY HAS RECOVERED INTO THE RANGE OF 1000 TO 2000 J/KG PER SPC MISANALYSED. BOTH THE RAP13 AND HRRR MODELS INDICATE THUNDERSTORM REDEVELOPMENT POSSIBLE ACROSS NORTHWEST IOWA OVER THE NEXT COUPLE OF HOURS...AND WITH VERY STRONG SHEAR ACROSS THE AREA WOULD EXPECT SOME OF THESE STORMS BECOMING SEVERE WITH VERY LARGE HAIL...DAMAGING WINDS...AND EVEN AN ISOLATED TORNADO IN THE VICINITY OF THE FRONTAL BOUNDARY. AS THE LOW PRESSURE MOVES TO NORTH AND EAST...ANY SEVERE CONVECTION WILL WIND DOWN PRETTY QUICKLY AFTER 00Z WITH MAINLY SOME WRAP AROUND SHOWERS ACROSS OUR NORTH OVERNIGHT. WITH COOLER AIR FILTERING IN BEHIND THE SYSTEM...LOWS LOOK TO DROP DOWN INTO THE MID 30S FAR WEST TO MID 40S IN THE FAR EAST. OTHER THAN SOME MORNING SHOWERS IN OUR NORTHEAST...THE REMAINDER OF FRIDAY SHOULD BE DECENT WITH DECREASING CLOUDS AND HIGHS IN THE 60S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 441 PM CDT THU MAY 8 2014 FOR SURE ONE OF THE MOST QUIET PERIODS IN THE FORECAST SHOULD BE FRIDAY EVENING. WEAK RIDGE WILL SHIFT EASTWARD DURING THE EVENING... WITH MID LEVEL WARM AIR ADVECTION INCREASING AS WAVE PUSHES INTO THE WESTERN HIGH PLAINS BY LATE NIGHT. INSTABILITY IS PRETTY MEAGER...AND WILL HAVE TO WORK INTO A FAIRLY DRIER ATMOSPHERE TO START. WILL KEEP COVERAGE ISOLATED TO PERHAPS SCATTERED AFTER 06Z...WITH BEST CHANCES SNEAKING IN LATE. THE FOCUS FOR PRECIPITATION WILL BECOME SOMEWHAT BETTER HEADING THROUGH THE DAY AND HEADING NORTHEASTWARD ON SATURDAY...PERHAPS PEAKING MIDDAY OR EARLY AFTERNOON IN THE FAR EAST/NORTHEAST. ENOUGH STEEPENING OF THE MID LEVEL LAPSE RATES AS DRIER AIR ALOFT WORKS TO THE SOUTH OF MID LEVEL WAVE TO THE NORTH TO WARRANT A SOMEWHAT BETTER MENTION OF THUNDER. WAVE LIFTS PAST FAIRLY QUICKLY SHEARING NORTHEAST ON SATURDAY EVENING WITH PERHAPS A LITTLE LINGERING SHOWER/THUNDER ACTIVITY IN THE EASTERN CWA...WITH COLD FRONT PUSHING ACROSS THE CWA. SHOULD GET A DECENT DRY PUSH ACROSS THE CWA DURING THE EVENING WITH A FAIRLY SUBSIDENT QUADRANT OF UPPER WAVE INTO CWA. START TO GET A DRASTIC DIVERGENCE IN MODEL SOLUTIONS AS EARLY AS SATURDAY NIGHT AND SUNDAY. HEADING INTO THE EXTENDED PORTION OF THE FORECAST FOR MONDAY THROUGH THURSDAY...HAVE SIDED TOWARD MORE AMPLIFIED AND SLOWER SOLUTION TO START WHICH MEANS HANGING BACK BETTER CHANCE FOR RAINFALL ON MONDAY...ESPECIALLY THE SOUTHEAST HALF. SUCH A DEEPER SYSTEM PER ENSEMBLE HINTS AND ECMWF LOOKS MORE FAVORED WITH LONG WAVE PATTERN SETTING UP AND THIS WILL START TO REBUILD THE RIDGE ACROSS THE NORTHERN PLAINS BY LATE WEEKEND. THIS SHOULD ENHANCE THE LIFT ACROSS STALLING LOWER TO MID LEVEL BOUNDARY. MAIN TROUGH LIFTING NORTHEAST THROUGH THE WESTERN AND NORTHERN PLAINS SHOULD PRODUCE ANOTHER PULSE OF MID LEVEL LIFT ACROSS THE LOW LEVEL ON SUNDAY NIGHT INTO MONDAY. COOLER AND DRYING FOR MONDAY NIGHT THROUGH TUESDAY NIGHT...AND THEN SOME ORIENTATION OF TROUGHINESS AGAIN BY WEDNESDAY INTO THURSDAY...BUT NOT ENOUGH AGREEMENT TO TRULY DEFINE A MORE CERTAIN THREAT FOR RAINFALL. DOES APPEAR THAT A PERIOD OF COOLER THAN NORMAL READINGS WILL BE IN PLACE AFTER SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1030 PM CDT THU MAY 8 2014 IFR TO LOW END MVFR CEILINGS TO PERSIST THROUGH MUCH OF THE NIGHT BUT TOWARDS SUNRISE AND SHORTLY AFTER THE CEILINGS ARE EXPECTED TO DISSIPATE GIVING WAY TO VFR CONDITIONS ON FRIDAY. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JM LONG TERM...CHAPMAN AVIATION...08
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
627 PM CDT THU MAY 8 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 441 PM CDT THU MAY 8 2014 CURRENT SURFACE ANALYSIS INDICATING THE SURFACE LOW PRESSURE CENTER LOCATED OVER NORTHEASTERN NEBRASKA INTO NORTHWESTERN IOWA...WITH A WARM FRONT EXTENDING EASTWARD TO JUST SOUTH OF WORTHINGTON AND JACKSON MINNESOTA. EARLIER ROUND OF CONVECTION STABILIZED THE ATMOSPHERE A BIT...BUT WITH BREAKS IN THE CLOUD COVER THROUGH THE AFTERNOON...INSTABILITY HAS RECOVERED INTO THE RANGE OF 1000 TO 2000 J/KG PER SPC MISANALYSED. BOTH THE RAP13 AND HRRR MODELS INDICATE THUNDERSTORM REDEVELOPMENT POSSIBLE ACROSS NORTHWEST IOWA OVER THE NEXT COUPLE OF HOURS...AND WITH VERY STRONG SHEAR ACROSS THE AREA WOULD EXPECT SOME OF THESE STORMS BECOMING SEVERE WITH VERY LARGE HAIL...DAMAGING WINDS...AND EVEN AN ISOLATED TORNADO IN THE VICINITY OF THE FRONTAL BOUNDARY. AS THE LOW PRESSURE MOVES TO NORTH AND EAST...ANY SEVERE CONVECTION WILL WIND DOWN PRETTY QUICKLY AFTER 00Z WITH MAINLY SOME WRAP AROUND SHOWERS ACROSS OUR NORTH OVERNIGHT. WITH COOLER AIR FILTERING IN BEHIND THE SYSTEM...LOWS LOOK TO DROP DOWN INTO THE MID 30S FAR WEST TO MID 40S IN THE FAR EAST. OTHER THAN SOME MORNING SHOWERS IN OUR NORTHEAST...THE REMAINDER OF FRIDAY SHOULD BE DECENT WITH DECREASING CLOUDS AND HIGHS IN THE 60S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 441 PM CDT THU MAY 8 2014 FOR SURE ONE OF THE MOST QUIET PERIODS IN THE FORECAST SHOULD BE FRIDAY EVENING. WEAK RIDGE WILL SHIFT EASTWARD DURING THE EVENING... WITH MID LEVEL WARM AIR ADVECTION INCREASING AS WAVE PUSHES INTO THE WESTERN HIGH PLAINS BY LATE NIGHT. INSTABILITY IS PRETTY MEAGER...AND WILL HAVE TO WORK INTO A FAIRLY DRIER ATMOSPHERE TO START. WILL KEEP COVERAGE ISOLATED TO PERHAPS SCATTERED AFTER 06Z...WITH BEST CHANCES SNEAKING IN LATE. THE FOCUS FOR PRECIPITATION WILL BECOME SOMEWHAT BETTER HEADING THROUGH THE DAY AND HEADING NORTHEASTWARD ON SATURDAY...PERHAPS PEAKING MIDDAY OR EARLY AFTERNOON IN THE FAR EAST/NORTHEAST. ENOUGH STEEPENING OF THE MID LEVEL LAPSE RATES AS DRIER AIR ALOFT WORKS TO THE SOUTH OF MID LEVEL WAVE TO THE NORTH TO WARRANT A SOMEWHAT BETTER MENTION OF THUNDER. WAVE LIFTS PAST FAIRLY QUICKLY SHEARING NORTHEAST ON SATURDAY EVENING WITH PERHAPS A LITTLE LINGERING SHOWER/THUNDER ACTIVITY IN THE EASTERN CWA...WITH COLD FRONT PUSHING ACROSS THE CWA. SHOULD GET A DECENT DRY PUSH ACROSS THE CWA DURING THE EVENING WITH A FAIRLY SUBSIDENT QUADRANT OF UPPER WAVE INTO CWA. START TO GET A DRASTIC DIVERGENCE IN MODEL SOLUTIONS AS EARLY AS SATURDAY NIGHT AND SUNDAY. HEADING INTO THE EXTENDED PORTION OF THE FORECAST FOR MONDAY THROUGH THURSDAY...HAVE SIDED TOWARD MORE AMPLIFIED AND SLOWER SOLUTION TO START WHICH MEANS HANGING BACK BETTER CHANCE FOR RAINFALL ON MONDAY...ESPECIALLY THE SOUTHEAST HALF. SUCH A DEEPER SYSTEM PER ENSEMBLE HINTS AND ECMWF LOOKS MORE FAVORED WITH LONG WAVE PATTERN SETTING UP AND THIS WILL START TO REBUILD THE RIDGE ACROSS THE NORTHERN PLAINS BY LATE WEEKEND. THIS SHOULD ENHANCE THE LIFT ACROSS STALLING LOWER TO MID LEVEL BOUNDARY. MAIN TROUGH LIFTING NORTHEAST THROUGH THE WESTERN AND NORTHERN PLAINS SHOULD PRODUCE ANOTHER PULSE OF MID LEVEL LIFT ACROSS THE LOW LEVEL ON SUNDAY NIGHT INTO MONDAY. COOLER AND DRYING FOR MONDAY NIGHT THROUGH TUESDAY NIGHT...AND THEN SOME ORIENTATION OF TROUGHINESS AGAIN BY WEDNESDAY INTO THURSDAY...BUT NOT ENOUGH AGREEMENT TO TRULY DEFINE A MORE CERTAIN THREAT FOR RAINFALL. DOES APPEAR THAT A PERIOD OF COOLER THAN NORMAL READINGS WILL BE IN PLACE AFTER SUNDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 627 PM CDT THU MAY 8 2014 STORMS WILL MOVE EAST OF THE EXTREME EASTERN PART OF THE FORECAST AREA BY 03Z. OTHERWISE WIDESPREAD LOW CLOUDS WEST OF SYSTEM WILL BRING CEILINGS 1-2K FEET TONIGHT WITH AREAS OF CEILINGS BELOW 1K FEET. A FEW AREAS OF VISIBILITY 3-5SM AND LOCALLY 1-3SM IN LIGHT RAIN AND FOG THROUGH 06Z MAINLY NORTH OF INTERSTATE 90. CLEARING TO VFR WITH UNLIMITED CEILINGS WILL TAKE PLACE FROM WEST TO EAST 09Z-18Z...THIS CLEARING WILL REACH WRN MN AND WRN IA 12Z-15Z. VFR WILL THEN CONTINUE THROUGH 10/00Z. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JM LONG TERM...CHAPMAN AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
339 PM CDT WED MAY 7 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 311 PM CDT WED MAY 7 2014 CURRENT SURFACE ANALYSIS SHOWING A SURFACE TROUGH AXIS LOCATED THROUGH NORTHWESTERN IOWA WITH A WARM FRONT EXTENDING EASTWARD ACROSS THAT AREA. HAVE SEEN SOME SCATTERED CONVECTION DEVELOP THROUGH THE NORTHERN JAMES RIVER VALLEY ALONG THE EDGE OF A STRONG CAP LOCATED ACROSS MOST OF THE REST OF THE CWA PER SPC MESOANALYSIS...WITH THIS CONVECTION TRENDING OFF TO THE NORTHEAST AT THIS TIME. THE RAP13 HAS HANDLED CONVECTIVE TRENDS FAIRLY WELL THROUGH THE DAY...WITH THE HRRR LESS SO...AND THE RAP AS WELL AS A COUPLE HI RES MODELS INDICATING ADDITIONAL CONVECTIVE DEVELOPMENT SOMEWHERE IN THE VICINITY OF THE IOWA GREAT LAKES/PORTIONS OF SOUTHWESTERN MINNESOTA IN THE LATE AFTERNOON/EARLY EVENING...IF THE CAP CAN BE BROKEN. SOUNDINGS WOULD SUGGEST THIS TO BE A POSSIBILITY BY LATE AFTERNOON AS A WEAK MID LEVEL WAVE TRACKS THROUGH THE REGION. IF THIS WERE TO OCCUR...PRESENT INSTABILITY AND EFFECTIVE SHEAR VALUES RUNNING AROUND 40 KTS WOULD INDICATE THAT SEVERE STORMS WOULD BE POSSIBLE WITH LARGE HAIL BEING THE MAIN THREAT. OTHERWISE...THE FOCUS FOR ADDITIONAL CONVECTION OVERNIGHT MAY BE CLOSER TO THE MID LEVEL FRONT ORIENTED FROM SOUTH CENTRAL SOUTH DAKOTA THEN CURVING NORTHWARD INTO NORTHEASTERN SOUTH DAKOTA. OTHERWISE...SHORTER TERM MODELS ALSO HINTING CONVECTION DEVELOPING THROUGH SOUTHERN NEBRASKA...POSSIBLY WORKING NORTHWARD INTO PORTIONS OF OUR SOUTHERN CWA LATE TONIGHT...THOUGH MUCH UNCERTAINTY ON THIS SCENARIO WITH MODEL DIFFERENCES. THERE WILL BE A WIDE RANGE OF TEMPERATURES ACROSS THE AREA TONIGHT...WITH COOL UPPER 40S IN OUR FAR WEST ON THE BACKSIDE OF THE LOW PRESSURE...WHILE DROPPING ONLY INTO THE LOWER 60S THROUGH NORTHWESTERN IOWA WHICH WILL REMAIN IN THE WARM SECTOR OF THE SYSTEM. MODELS IN FAIRLY DECENT AGREEMENT ON THE SURFACE LOW PULLING INTO SOUTHWESTERN MINNESOTA BY THURSDAY EVENING...THOUGH DIFFERING ON STRENGTH AND DURATION OF THE DRY SLOT ACROSS OUR AREA. THE NAM/GEM ARE MORE AGGRESSIVE WITH THIS FEATURE...KEEPING OUR EAST FAIRLY DRY THROUGH MUCH OF THE DAY...THROUGH THE GFS/ECMWF OFFER A WETTER SOLUTION. IN ANY EVENT...BETTER CHANCES OF PRECIPITATION WILL EXIST ACROSS THE NORTH AND WEST IN THE COOLER/DEEPER SATURATED LAYER. THERE AGAIN WILL BE A WIDE RANGE IN TEMPERATURES ACROSS THE AREA...WITH PLACES IN THE WARM SECTOR OUT AHEAD OF THE LOW CLIMBING INTO THE 70S TO NEAR 80...WHILE BACK TO THE WEST HIGHS WILL ONLY MAKE IT INTO THE 50S. AS FAR AS SEVERE WEATHER...IT WILL PROBABLY COME DOWN TO TIMING...AS THE INSTABILITY WANES PRETTY QUICKLY FROM WEST TO EAST THROUGH THE DAY AS THE LOW MOVES EASTWARD...THOUGH IF IT WERE TO OCCUR IT WOULD PROBABLY BE IN OUR FAR EAST DURING THE AFTERNOON AT MAXIMUM HEATING. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 311 PM CDT WED MAY 7 2014 WAVE EXITS RAPIDLY TO THE NORTHEAST THURSDAY NIGHT MAINLY LEAVING RESIDUAL CHANCES FOR RAINFALL. THE ATMOSPHERE STABILIZES QUICKLY... AND THE BEST CHANCE FOR MEASURABLE RAIN WILL BE ALONG AND BEHIND THE WIND SHIFT/COLD FRONT WHERE THE MOISTURE IS DEEPER IN THE STABLE AIR. LOOKING FURTHER TO THE SOUTHEAST...NORTHWEST IA IS MORE IN THE SHALLOW MOISTURE/DRY SLOT AREA SO NOT REAL KEEN ON PRECIP CHANCES IN THAT LOCATION AT THIS TIME. FRIDAY WILL BE A PLEASANT DAY...ALBEIT RATHER BREEZY EAST OF THE JAMES RIVER VALLEY. BUT A WELL MIXED ATMOSPHERE SHOULD GIVE HIGHS WELL INTO THE 60S. IF WE MIX A BIT HIGHER...WE MAY NEED TO TACK ON A COUPLE OF DEGREES MORE TO THESE READINGS. FRIDAY NIGHT IS HIGHLIGHTED BY A STRONG SURGE OF THETAE ADVECTION WHICH IS BASICALLY HARMLESS AS THE ATMOSPHERE REMAINS MOISTURE STARVED BELOW ABOUT 600MB. THERE MAY BE A FEW STORMS MOVING INTO SOUTH CENTRAL SD BY LATE TONIGHT...BUT OTHER LOCATIONS WILL REMAIN DRY WITH LOWS WELL INTO THE 40S. THE THETAE ADVECTION IS IN ADVANCE OF THE NEXT SHORT WAVE PASSAGE ON SATURDAY. BOTH THE NAM AND GFS SHOW THE CRUX OF THE WAVE MOVING THROUGH OUR SOUTHERN AND EASTERN ZONES PER THE UPPER QG FORCING. LOW LEVEL MOISTURE DOES APPEAR TO PICK UP AHEAD OF THE SURFACE WIND SHIFT...SO 50 POPS WERE PLACED EAST OF I 29. ELEVATED INSTABILITY ALSO LOOKS RATHER ABUNDANT AT THIS TIME...SO JUST OPTED TO GO PURE THUNDERSTORMS FOR NOW FOR THE AFTERNOON HOURS GENERALLY ALONG AND EAST OF I 29. FOR HIGHS...SATURDAY LOOKS LIKE ANOTHER BREEZY AND WELL MIXED DAY AND WITH A WARM LOWER ATMOSPHERE...WE ARE LOOKING AT UPPER 60S IN HURON TO MID 70S AT SIOUX CITY AND STORM LAKE. IN THE EXTENDED...THERE IS STILL QUITE A BIT OF DISCREPANCY BETWEEN THE VARIOUS DETERMINISTIC SOLUTIONS. THEREFORE BLENDED THE SOLUTIONS. THE ECMWF CONTINUES TO BE THE SOLUTION WHICH IS THE MOST BULLISH WITH REGARDS TO RAINFALL IN THE SUNDAY THROUGH MONDAY NIGHT TIME FRAME. BUT ADMITTEDLY IT IS DIFFICULT TO TELL BECAUSE EACH MODEL HAS BEEN VERY CONSISTENT WITH THEIR RESPECTIVE OUTPUTS. MORE CERTAIN IS THAT TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH THE MIDDLE OF NEXT WEEK WITH BREEZY CONDITIONS LIKELY EARLY IN THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1211 PM CDT WED MAY 7 2014 LOW CONFIDENCE IS CONVECTIVE CHANCES THROUGH THE TAF PERIOD WITH MODEL DIFFERENCES...THOUGH MAY SEE SCATTERED THUNDERSTORMS DEVELOP IN SOUTHWESTERN MINNESOTA LATE THIS AFTERNOON...THEN THROUGH CENTRAL SOUTH DAKOTA TONIGHT INTO TOMORROW MORNING. FARTHER TO THE SOUTH AND EAST...DRY SLOT MAY RULE AND DID NOT INCLUDE CONVECTION AT KFSD AND KSUX...THOUGH CANNOT RULE IT OUT. DOES LOOK LIKE CEILINGS WILL LOWER LATER TONIGHT INTO THE MVFR/UPPER IFR RANGE OVER PORTIONS OF THE AREA. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JM LONG TERM...MJ AVIATION...JM
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
104 PM CDT WED MAY 7 2014 .UPDATE... SEE UPDATED AVIATION DISCUSSION BELOW. MADE A FEW CHANGES TO THE FORECAST THIS MORNING...MAINLY TO DECREASE POP THROUGH THIS AFTERNOON. AN UPPER LEVEL SHORT WAVE JUST OFF TO THE WEST OF ABERDEEN WILL CONTINUE TO PUSH NORTHEASTWARD INTO NORTH DAKOTA. THIS SYSTEM IS PRODUCING LIGHT SHOWERS ACROSS NORTH CENTRAL SOUTH DAKOTA. BETTER LLM AND SHEAR FURTHER EAST IS RESULTING IN MARGINALLY STRONG STORMS WITH RADAR SHOWING SOME SMALL HAIL POSSIBLE. THESE STORMS SHOULD CONTINUE PUSHING INTO SE NORTH DAKOTA WITHIN THE NEXT FEW HOURS. THERE IS A GOOD POSSIBILITY FOR DRY CONDITIONS THROUGH THIS AFTERNOON BEFORE THE NEXT UPPER LEVEL SHORT WAVE MOVES INTO THE REGION FROM THE SOUTHWEST. && .PREVIOUS DISCUSSION... .SHORT TERM...THROUGH FRIDAY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY CONTINUES BOTH SOUTH AND WEST OF THE CWA THANKS TO SOUTHWEST FLOW ALOFT WITH WEAK EMBEDDED WAVES. THE 06Z HRRR BRINGS CONVECTIVE REMNANTS INTO THE WESTERN CWA THROUGH THE MORNING HOURS...BUT HAVE ALREADY SEEN SIMILAR ATTEMPTS BY SHOWERS TO CROSS INTO THE FORECAST AREA...ONLY TO WASH OUT...SO FORECASTER CONFIDENCE CONTINUES TO REMAIN LOW EVEN IN THE NEAR TERM. MODELS DO HAVE A BETTER DEFINED WAVE MOVING UP FROM THE SOUTH TODAY. BEST ISENTROPIC FORCING WILL SET UP JUST NORTH OF A KMBG TO KPHP LINE. INSTABILITY PEAKS JUST SOUTH OF A WARM FRONT FOR THE EASTERN CWA THIS AFTERNOON AS WELL. LOOKING AT NAM/RAP PROFILES...SURFACE BASED CONVECTION APPEARS UNLIKELY AS THE FRONT IS SOUTH OF THE CWA...AND GUIDANCE HAS A DIFFICULT TIME WARMING ENOUGH TO OVERCOME THE INVERSION. STEEP LAPSE RATES ABOVE THE INVERSION WITH STRONG SOUTHWEST MID LEVEL FLOW WILL SUPPORT A HAIL THREAT IF ANY STORMS DO DEVELOP. OVERNIGHT...A COUPLED JET STRUCTURE WILL SUPPORT AN AREA OF RAIN THAT WILL LIFT OUT OF THE NEBRASKA PANHANDLE THROUGH WESTERN/CENTRAL SOUTH DAKOTA. MOST OF THE GUIDANCE TAKES THIS FEATURE NORTHEAST BETWEEN KPIR AND KMBG...THOUGH SREF GUIDANCE IS A TAD FARTHER WEST. SREF PROBABILITIES SUGGEST FAIRLY HIGH QPF POTENTIAL WITH THIS FEATURE...WHICH IS SUPPORTED WITHIN MOST GUIDANCE. THE GFS IS PEGGED AT NEARLY 30 MICROBARS OF LIFT BY 12Z THURSDAY. TROWAL WRAP AROUND LIGHT RAIN WILL CONTINUE THROUGH THE DAY...BUT WE WILL SEE ISENTROPIC DOWNGLIDE BY LATE AFTERNOON/EVENING HELPING TO DRY US OUT FOR FRIDAY. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY THE EXTENDED PERIOD CONTINUES THE ACTIVE PATTERN WITH A COUPLE OF SYSTEMS MOVING THROUGH. THE FIRST WEAKER WAVE MOVES OFF THE ROCKIES FRIDAY NIGHT AND INTO EASTERN SD SATURDAY BRINGING SOME SHOWERS AND TSTORMS. THERE WILL LIKELY BE A BRIEF BREAK IN PRECIP SAT MORNING BEFORE A MORE WELL DEVELOPED SFC LOW ENTERS THE CENTRAL PLAINS SAT NIGHT. AT THE SAME TIME AN UPPER LOW WILL DROP DOWN INTO ND. WHILE THE MODELS AGREE ON THE SFC SYNOPTIC PATTERN...THERE IS SOME DISCREPANCY AT JUST WHEN THE UPPER TROF WILL BEGIN TO AFFECT THE NORTHERN PLAINS. THIS WILL INFLUENCE AREAL COVERAGE OF PRECIP DURING ANY GIVEN PERIOD FROM SAT NIGHT THROUGH TUESDAY. THE ECMWF KEEPS THE PRECIP ONLY OVER THE FAR SOUTHERN CWA WHILE THE GFS HAS THE ENERGY FROM THE UPPER LOW DIGGING A LITTLE FARTHER SOUTH ON SUNDAY. KEPT ALLBLEND POPS FOR NOW OVER THE WEEKEND BUT A DRIER SOLUTION IS POSSIBLE. TEMPERATURES WILL TREND DOWN THROUGH THE PERIOD WITH THE COOLEST TEMPS OCCURRING WHEN THE LONGWAVE TROUGH MOVES OVER THE PLAINS. TEMPS WILL BE AROUND 10 DEGREES COOLER THAN AVERAGE BY THE LATTER HALF OF THE EXTENDED. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS REGIONAL SATL AND RADAR ANALYSIS SHOWS LAST OF THE MORNING SHOWERS AND TSTORMS EXITING THE AREA TO THE NORTH AND NORTHEAST AND SOME BINOVC OR CLR SKIES DEVELOPING ACROSS CENTRAL AND NERN SD. VFR CONDITIONS EXPECTED AT ALL TERMINALS INTO THE AFTN. KEPT VCTS FOR LATER THIS AFTN AT ATY AS EAST CENTRAL SD STANDS THE BEST CHC TO SEE TSTORMS DEVELOP. PUSHED RAIN CHANCES BACK FARTHER INTO THE EVENING FOR ABR AS LATEST GUIDANCE SUGGESTS AREA OF PCPN MOVING IN AFTER SUNSET AND LATE TONIGHT. HELD ONTO RAIN CHANCES FOR PIR AND MBG EARLY THIS EVENING WITH BEST SHOT OF RAIN LATE AS WELL. RAIN IS EXPECTED TO CONTINUE FOR ALL TAF SITES DURING THE MRNG HRS THURSDAY WITH MVFR CIGS. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...SD SHORT TERM...CONNELLY LONG TERM...WISE AVIATION...VIPOND WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1058 AM CDT WED MAY 7 2014 .UPDATE... MADE A FEW CHANGES TO THE FORECAST THIS MORNING...MAINLY TO DECREASE POP THROUGH THIS AFTERNOON. AN UPPER LEVEL SHORT WAVE JUST OFF TO THE WEST OF ABERDEEN WILL CONTINUE TO PUSH NORTHEASTWARD INTO NORTH DAKOTA. THIS SYSTEM IS PRODUCING LIGHT SHOWERS ACROSS NORTH CENTRAL SOUTH DAKOTA. BETTER LLM AND SHEAR FURTHER EAST IS RESULTING IN MARGINALLY STRONG STORMS WITH RADAR SHOWING SOME SMALL HAIL POSSIBLE. THESE STORMS SHOULD CONTINUE PUSHING INTO SE NORTH DAKOTA WITHIN THE NEXT FEW HOURS. THERE IS A GOOD POSSIBILITY FOR DRY CONDITIONS THROUGH THIS AFTERNOON BEFORE THE NEXT UPPER LEVEL SHORT WAVE MOVES INTO THE REGION FROM THE SOUTHWEST. && .PREVIOUS DISCUSSION... .SHORT TERM...THROUGH FRIDAY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY CONTINUES BOTH SOUTH AND WEST OF THE CWA THANKS TO SOUTHWEST FLOW ALOFT WITH WEAK EMBEDDED WAVES. THE 06Z HRRR BRINGS CONVECTIVE REMNANTS INTO THE WESTERN CWA THROUGH THE MORNING HOURS...BUT HAVE ALREADY SEEN SIMILAR ATTEMPTS BY SHOWERS TO CROSS INTO THE FORECAST AREA...ONLY TO WASH OUT...SO FORECASTER CONFIDENCE CONTINUES TO REMAIN LOW EVEN IN THE NEAR TERM. MODELS DO HAVE A BETTER DEFINED WAVE MOVING UP FROM THE SOUTH TODAY. BEST ISENTROPIC FORCING WILL SET UP JUST NORTH OF A KMBG TO KPHP LINE. INSTABILITY PEAKS JUST SOUTH OF A WARM FRONT FOR THE EASTERN CWA THIS AFTERNOON AS WELL. LOOKING AT NAM/RAP PROFILES...SURFACE BASED CONVECTION APPEARS UNLIKELY AS THE FRONT IS SOUTH OF THE CWA...AND GUIDANCE HAS A DIFFICULT TIME WARMING ENOUGH TO OVERCOME THE INVERSION. STEEP LAPSE RATES ABOVE THE INVERSION WITH STRONG SOUTHWEST MID LEVEL FLOW WILL SUPPORT A HAIL THREAT IF ANY STORMS DO DEVELOP. OVERNIGHT...A COUPLED JET STRUCTURE WILL SUPPORT AN AREA OF RAIN THAT WILL LIFT OUT OF THE NEBRASKA PANHANDLE THROUGH WESTERN/CENTRAL SOUTH DAKOTA. MOST OF THE GUIDANCE TAKES THIS FEATURE NORTHEAST BETWEEN KPIR AND KMBG...THOUGH SREF GUIDANCE IS A TAD FARTHER WEST. SREF PROBABILITIES SUGGEST FAIRLY HIGH QPF POTENTIAL WITH THIS FEATURE...WHICH IS SUPPORTED WITHIN MOST GUIDANCE. THE GFS IS PEGGED AT NEARLY 30 MICROBARS OF LIFT BY 12Z THURSDAY. TROWAL WRAP AROUND LIGHT RAIN WILL CONTINUE THROUGH THE DAY...BUT WE WILL SEE ISENTROPIC DOWNGLIDE BY LATE AFTERNOON/EVENING HELPING TO DRY US OUT FOR FRIDAY. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY THE EXTENDED PERIOD CONTINUES THE ACTIVE PATTERN WITH A COUPLE OF SYSTEMS MOVING THROUGH. THE FIRST WEAKER WAVE MOVES OFF THE ROCKIES FRIDAY NIGHT AND INTO EASTERN SD SATURDAY BRINGING SOME SHOWERS AND TSTORMS. THERE WILL LIKELY BE A BRIEF BREAK IN PRECIP SAT MORNING BEFORE A MORE WELL DEVELOPED SFC LOW ENTERS THE CENTRAL PLAINS SAT NIGHT. AT THE SAME TIME AN UPPER LOW WILL DROP DOWN INTO ND. WHILE THE MODELS AGREE ON THE SFC SYNOPTIC PATTERN...THERE IS SOME DISCREPANCY AT JUST WHEN THE UPPER TROF WILL BEGIN TO AFFECT THE NORTHERN PLAINS. THIS WILL INFLUENCE AREAL COVERAGE OF PRECIP DURING ANY GIVEN PERIOD FROM SAT NIGHT THROUGH TUESDAY. THE ECMWF KEEPS THE PRECIP ONLY OVER THE FAR SOUTHERN CWA WHILE THE GFS HAS THE ENERGY FROM THE UPPER LOW DIGGING A LITTLE FARTHER SOUTH ON SUNDAY. KEPT ALLBLEND POPS FOR NOW OVER THE WEEKEND BUT A DRIER SOLUTION IS POSSIBLE. TEMPERATURES WILL TREND DOWN THROUGH THE PERIOD WITH THE COOLEST TEMPS OCCURRING WHEN THE LONGWAVE TROUGH MOVES OVER THE PLAINS. TEMPS WILL BE AROUND 10 DEGREES COOLER THAN AVERAGE BY THE LATTER HALF OF THE EXTENDED. && .AVIATION... 12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE EXPECTED THROUGH EARLY AFTERNOON. SHOWERS AND THUNDERSTORMS WILL SPREAD EASTWARD DURING THE LATE AFTERNOON AND EVENING. THE MOST LIKELY LOCATION TO SEE THUNDERSTORM ACTIVITY WILL BE ACROSS THE SOUTHERN AND FAR EASTERN CWA...POSSIBLY AFFECTING KPIR AND KATY FROM 21Z. CIGS WILL FALL INTO THE MVFR CATEGORY BY LATE AFTERNOON...THEN INTO THE IFR CATEGORY BEHIND THE LOW OVERNIGHT. LOWER VSBYS WILL BE POSSIBLE WITH THE PRECIPITATION AS WELL. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...SD SHORT TERM...CONNELLY LONG TERM...WISE AVIATION...WISE WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
656 AM CDT WED MAY 7 2014 .UPDATE... KNOCKED BACK EASTERN PROGRESSION OF POPS THIS MORNING AS LITTLE IF ANYTHING IS MAKING IT EAST OF THE MISSOURI RIVER ON RADAR. ALSO TOOK OUT MENTION OF THUNDER THIS MORNING. BEST CHANCES FOR TSTORM DEVELOPMENT APPEAR TO BE 20Z INTO THIS EVENING. SEE UPDATED AVIATION DISCUSSION BELOW. && .PREVIOUS DISCUSSION... .SHORT TERM...THROUGH FRIDAY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY CONTINUES BOTH SOUTH AND WEST OF THE CWA THANKS TO SOUTHWEST FLOW ALOFT WITH WEAK EMBEDDED WAVES. THE 06Z HRRR BRINGS CONVECTIVE REMNANTS INTO THE WESTERN CWA THROUGH THE MORNING HOURS...BUT HAVE ALREADY SEEN SIMILAR ATTEMPTS BY SHOWERS TO CROSS INTO THE FORECAST AREA...ONLY TO WASH OUT...SO FORECASTER CONFIDENCE CONTINUES TO REMAIN LOW EVEN IN THE NEAR TERM. MODELS DO HAVE A BETTER DEFINED WAVE MOVING UP FROM THE SOUTH TODAY. BEST ISENTROPIC FORCING WILL SET UP JUST NORTH OF A KMBG TO KPHP LINE. INSTABILITY PEAKS JUST SOUTH OF A WARM FRONT FOR THE EASTERN CWA THIS AFTERNOON AS WELL. LOOKING AT NAM/RAP PROFILES...SURFACE BASED CONVECTION APPEARS UNLIKELY AS THE FRONT IS SOUTH OF THE CWA...AND GUIDANCE HAS A DIFFICULT TIME WARMING ENOUGH TO OVERCOME THE INVERSION. STEEP LAPSE RATES ABOVE THE INVERSION WITH STRONG SOUTHWEST MID LEVEL FLOW WILL SUPPORT A HAIL THREAT IF ANY STORMS DO DEVELOP. OVERNIGHT...A COUPLED JET STRUCTURE WILL SUPPORT AN AREA OF RAIN THAT WILL LIFT OUT OF THE NEBRASKA PANHANDLE THROUGH WESTERN/CENTRAL SOUTH DAKOTA. MOST OF THE GUIDANCE TAKES THIS FEATURE NORTHEAST BETWEEN KPIR AND KMBG...THOUGH SREF GUIDANCE IS A TAD FARTHER WEST. SREF PROBABILITIES SUGGEST FAIRLY HIGH QPF POTENTIAL WITH THIS FEATURE...WHICH IS SUPPORTED WITHIN MOST GUIDANCE. THE GFS IS PEGGED AT NEARLY 30 MICROBARS OF LIFT BY 12Z THURSDAY. TROWAL WRAP AROUND LIGHT RAIN WILL CONTINUE THROUGH THE DAY...BUT WE WILL SEE ISENTROPIC DOWNGLIDE BY LATE AFTERNOON/EVENING HELPING TO DRY US OUT FOR FRIDAY. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY THE EXTENDED PERIOD CONTINUES THE ACTIVE PATTERN WITH A COUPLE OF SYSTEMS MOVING THROUGH. THE FIRST WEAKER WAVE MOVES OFF THE ROCKIES FRIDAY NIGHT AND INTO EASTERN SD SATURDAY BRINGING SOME SHOWERS AND TSTORMS. THERE WILL LIKELY BE A BRIEF BREAK IN PRECIP SAT MORNING BEFORE A MORE WELL DEVELOPED SFC LOW ENTERS THE CENTRAL PLAINS SAT NIGHT. AT THE SAME TIME AN UPPER LOW WILL DROP DOWN INTO ND. WHILE THE MODELS AGREE ON THE SFC SYNOPTIC PATTERN...THERE IS SOME DISCREPANCY AT JUST WHEN THE UPPER TROF WILL BEGIN TO AFFECT THE NORTHERN PLAINS. THIS WILL INFLUENCE AREAL COVERAGE OF PRECIP DURING ANY GIVEN PERIOD FROM SAT NIGHT THROUGH TUESDAY. THE ECMWF KEEPS THE PRECIP ONLY OVER THE FAR SOUTHERN CWA WHILE THE GFS HAS THE ENERGY FROM THE UPPER LOW DIGGING A LITTLE FARTHER SOUTH ON SUNDAY. KEPT ALLBLEND POPS FOR NOW OVER THE WEEKEND BUT A DRIER SOLUTION IS POSSIBLE. TEMPERATURES WILL TREND DOWN THROUGH THE PERIOD WITH THE COOLEST TEMPS OCCURRING WHEN THE LONGWAVE TROUGH MOVES OVER THE PLAINS. TEMPS WILL BE AROUND 10 DEGREES COOLER THAN AVERAGE BY THE LATTER HALF OF THE EXTENDED. && .AVIATION... 12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE EXPECTED THROUGH EARLY AFTERNOON. SHOWERS AND THUNDERSTORMS WILL SPREAD EASTWARD DURING THE LATE AFTERNOON AND EVENING. THE MOST LIKELY LOCATION TO SEE THUNDERSTORM ACTIVITY WILL BE ACROSS THE SOUTHERN AND FAR EASTERN CWA...POSSIBLY AFFECTING KPIR AND KATY FROM 21Z. CIGS WILL FALL INTO THE MVFR CATEGORY BY LATE AFTERNOON...THEN INTO THE IFR CATEGORY BEHIND THE LOW OVERNIGHT. LOWER VSBYS WILL BE POSSIBLE WITH THE PRECIPITATION AS WELL. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...WISE SHORT TERM...CONNELLY LONG TERM...WISE AVIATION...WISE WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
342 AM CDT WED MAY 7 2014 .SHORT TERM...THROUGH FRIDAY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY CONTINUES BOTH SOUTH AND WEST OF THE CWA THANKS TO SOUTHWEST FLOW ALOFT WITH WEAK EMBEDDED WAVES. THE 06Z HRRR BRINGS CONVECTIVE REMNANTS INTO THE WESTERN CWA THROUGH THE MORNING HOURS...BUT HAVE ALREADY SEEN SIMILAR ATTEMPTS BY SHOWERS TO CROSS INTO THE FORECAST AREA...ONLY TO WASH OUT...SO FORECASTER CONFIDENCE CONTINUES TO REMAIN LOW EVEN IN THE NEAR TERM. MODELS DO HAVE A BETTER DEFINED WAVE MOVING UP FROM THE SOUTH TODAY. BEST ISENTROPIC FORCING WILL SET UP JUST NORTH OF A KMBG TO KPHP LINE. INSTABILITY PEAKS JUST SOUTH OF A WARM FRONT FOR THE EASTERN CWA THIS AFTERNOON AS WELL. LOOKING AT NAM/RAP PROFILES...SURFACE BASED CONVECTION APPEARS UNLIKELY AS THE FRONT IS SOUTH OF THE CWA...AND GUIDANCE HAS A DIFFICULT TIME WARMING ENOUGH TO OVERCOME THE INVERSION. STEEP LAPSE RATES ABOVE THE INVERSION WITH STRONG SOUTHWEST MID LEVEL FLOW WILL SUPPORT A HAIL THREAT IF ANY STORMS DO DEVELOP. OVERNIGHT...A COUPLED JET STRUCTURE WILL SUPPORT AN AREA OF RAIN THAT WILL LIFT OUT OF THE NEBRASKA PANHANDLE THROUGH WESTERN/CENTRAL SOUTH DAKOTA. MOST OF THE GUIDANCE TAKES THIS FEATURE NORTHEAST BETWEEN KPIR AND KMBG...THOUGH SREF GUIDANCE IS A TAD FARTHER WEST. SREF PROBABILITIES SUGGEST FAIRLY HIGH QPF POTENTIAL WITH THIS FEATURE...WHICH IS SUPPORTED WITHIN MOST GUIDANCE. THE GFS IS PEGGED AT NEARLY 30 MICROBARS OF LIFT BY 12Z THURSDAY. TROWAL WRAP AROUND LIGHT RAIN WILL CONTINUE THROUGH THE DAY...BUT WE WILL SEE ISENTROPIC DOWNGLIDE BY LATE AFTERNOON/EVENING HELPING TO DRY US OUT FOR FRIDAY. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY THE EXTENDED PERIOD CONTINUES THE ACTIVE PATTERN WITH A COUPLE OF SYSTEMS MOVING THROUGH. THE FIRST WEAKER WAVE MOVES OFF THE ROCKIES FRIDAY NIGHT AND INTO EASTERN SD SATURDAY BRINGING SOME SHOWERS AND TSTORMS. THERE WILL LIKELY BE A BRIEF BREAK IN PRECIP SAT MORNING BEFORE A MORE WELL DEVELOPED SFC LOW ENTERS THE CENTRAL PLAINS SAT NIGHT. AT THE SAME TIME AN UPPER LOW WILL DROP DOWN INTO ND. WHILE THE MODELS AGREE ON THE SFC SYNOPTIC PATTERN...THERE IS SOME DISCREPANCY AT JUST WHEN THE UPPER TROF WILL BEGIN TO AFFECT THE NORTHERN PLAINS. THIS WILL INFLUENCE AREAL COVERAGE OF PRECIP DURING ANY GIVEN PERIOD FROM SAT NIGHT THROUGH TUESDAY. THE ECMWF KEEPS THE PRECIP ONLY OVER THE FAR SOUTHERN CWA WHILE THE GFS HAS THE ENERGY FROM THE UPPER LOW DIGGING A LITTLE FARTHER SOUTH ON SUNDAY. KEPT ALLBLEND POPS FOR NOW OVER THE WEEKEND BUT A DRIER SOLUTION IS POSSIBLE. TEMPERATURES WILL TREND DOWN THROUGH THE PERIOD WITH THE COOLEST TEMPS OCCURRING WHEN THE LONGWAVE TROUGH MOVES OVER THE PLAINS. TEMPS WILL BE AROUND 10 DEGREES COOLER THAN AVERAGE BY THE LATTER HALF OF THE EXTENDED. && .AVIATION... 06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THROUGH THE OVERNIGHT HOURS. SHOWER AND THUNDERSTORMS WILL OVERSPREAD THE WESTERN CWA DURING THE LATE MORNING AND EARLY AFTERNOON HOURS...THEN WILL SPREAD EASTWARD DURING THE LATE AFTERNOON AND EVENING. THE MOST LIKELY LOCATION TO SEE THUNDERSTORMS ACTIVITY WILL BE ACROSS THE SOUTHERN AND FAR EASTERN CWA...POSSIBLY AFFECTING KPIR AND KATY. CIGS WILL FALL INTO THE MVFR CATEGORY BY MIDDAY...THEN INTO THE VFR CATEGORY DURING THE LATE AFTERNOON HOURS. MVFR VSBYS WILL BE POSSIBLE WITH THE PRECIPITATION AS WELL. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...CONNELLY LONG TERM...WISE AVIATION...WISE WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
323 PM CDT WED MAY 7 2014 .SHORT TERM (TONIGHT THROUGH ...COMPLEX AND DIFFICULT FORECAST THROUGH THE SHORT TERM REGARDING POPS. WEAK UPPER LEVEL DISTURBANCE AND SUBTROPICAL PLUME OF MOISTURE FROM THE PACIFIC HAS GENERATED WEAK RETURNS ON THE RADAR TODAY ACROSS THE CWA. SPRINKLES AND LIGHT RAIN HAVE REACHED THE GROUND IN ISOLATED LOCATIONS...BUT A DRY 900-650MB LAYER HAS RESULTED IN MOSTLY VIRGA THUS FAR. MODELS VARY WIDELY TONIGHT INTO THURSDAY MORNING WITH PRECIP PLACEMENT... AND THE POORLY SAMPLED PACIFIC PLUME OF MOISTURE AND EMBEDDED DISTURBANCES UPSTREAM ACROSS MEXICO ARE NOT HELPING. GENERALLY MODELS DO SHOW THE AFOREMENTIONED DRY LAYER MOISTENING FROM WEST TO EAST OVERNIGHT THROUGH MIDDAY THURSDAY...ALONG WITH 850MB THETA-E RIDGE AXIS WEST OF THE RIO GRANDE MOVING EAST ON THURSDAY. PWATS BY MIDDAY THURSDAY ARE AROUND 1.8-2 INCHES ACROSS THE CWA. GFS AND HRRR INDICATING ELEVATED CONVECTION MOVING NORTHEAST OUT OF MEXICO INTO THE WESTERN CWA LATER THIS EVENING AND OVERNIGHT... ALONG WITH 4KM TEXAS TECH WRF. ECMWF EVEN MORE BULLISH WITH QPF AMOUNTS AND FARTHER EAST INTO THE COASTAL BEND AND EASTERN BRUSH COUNTRY. HOWEVER...NAM12 WELL NORTHWEST OF THE AREA WITH QPF AND HI RES NMM/ARW KEYING IN ON AREAS SOUTH OF THE CWA. BASED ON SATELLITE TRENDS UPSTREAM IN MEXICO HAVE SIDED TOWARDS LOW END CHANCE POPS FOR NOW ACROSS THE WESTERN HALF OF THE CWA TONIGHT... WITH THE FEELING THAT MID LEVEL DISTURBANCE IN THE SOUTHWEST FLOW ALOFT AND MOISTENING OF THE DRY LAYER OUT WEST WILL ALLOW FOR ELEVATED PRECIP TO REACH THE GROUND. DURING THE DAY ON THURSDAY...AGAIN MODELS ARE GENERALLY CONSISTENT WITH PLACEMENT OF MOISTURE AXIS MOVING WEST INTO CENTRAL AND EVENTUALLY AREAS OF THE CWA. GOOD CHANCES FOR SURFACE BASED CONVECTION TO DEVELOP THE BRUSH COUNTRY AND INLAND AREAS OF THE COASTAL BEND DURING THE DAY ON THURSDAY...AS CAP ERODES AND MID LEVEL DISTURBANCE CONTINUES EAST ACROSS THE CWA. BETTER JET DYNAMICS MAY REMAIN JUST NORTH AND NORTHWEST OF THE CWA. HOWEVER...THERE IS SUFFICIENT DEEP LAYER SHEAR IN PLACE AND IF ANY SIGNIFICANT BREAKS IN CLOUD COVER OCCUR ACROSS THE CENTRAL AND WESTERN CWA THERE COULD BE A FEW STRONGER STORMS. CONVECTION COULD LINGER INTO THURSDAY NIGHT ACROSS THE COASTAL BEND AND VICTORIA CROSSROADS. OVERALL THROUGH...CONFIDENCE IN THE ENTIRE SHORT TERM FORECAST IS LOW GIVEN AFOREMENTIONED REASONS. && .LONG-TERM (FRIDAY THROUGH WEDNESDAY)...NOT A WHOLE LOT OF MODEL CONSENSUS IN THE EXTENDED PERIOD...AND DIFFICULT TO FIND A CLEAR MODEL WINNER SO CONFIDENCE IN THIS PACKAGE IS SOMEWHAT LOWER THAN TYPICAL. GENERAL IDEA IS FOR AN UPPER DISTURBANCE TO TRIGGER SCATTERED PRECIPITATION FRIDAY...THEN TAPERING FRIDAY NIGHT AND SATURDAY. AFTER RIDGING BUILDS IN FOR SUNDAY...A STRONGER WAVE LOOKS TO FORCE A COLD FRONT THROUGH THE REGION. GFS IS MORE THAN 12 HOURS FASTER WITH THE FRONTAL PASSAGE THAN THE ECMWF. BASED ON PROJECTED UPPER AIR PATTERN HAVE SLIGHTLY MORE FAITH IN THE ECMWF SOLUTION AT THIS TIME. TEMPERATURES FROM MONDAY THROUGH WEDNESDAY WILL BE HIGHLY DEPENDENT ON TIMING OF THE FRONT AND OF SURFACE HIGH PRESSURE THAT BUILDS IN BEHIND THE FRONT. GFS AS USUAL IS VERY AGGRESSIVE WITH COOL AIR BEHIND THE FRONT...SO FORECAST PACKAGE IS SOMEWHAT WARMER AND CLOUDIER THAN WHAT NUMERICAL GUIDANCE WOULD SUGGEST. BY WEDNESDAY SUBSIDENT HIGH PRESSURE IS WELL ESTABLISHED WITH DRIER OFFSHORE FLOW. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 75 86 73 87 73 / 20 50 30 40 30 VICTORIA 73 84 73 86 70 / 20 50 30 40 30 LAREDO 77 94 75 97 76 / 40 30 20 30 20 ALICE 74 89 73 90 72 / 30 50 30 40 30 ROCKPORT 74 80 73 86 73 / 20 30 30 40 30 COTULLA 74 92 72 93 71 / 40 50 20 30 20 KINGSVILLE 74 88 74 89 73 / 20 50 30 30 20 NAVY CORPUS 74 82 74 84 74 / 20 40 30 30 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ JR/76...SHORT TERM JV/71...LONG TERM
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1133 PM CDT Tue May 6 2014 .UPDATE... Increased overnight lows and introduced a slight chance of thunderstorms along the I-10 corridor and northeast into the Mason...Brady and San Saba. && .DISCUSSION... Extensive mid/upper clouds associated with the subtropical jet and isolated thunderstorms in southwest Texas were moving northeast across the region. Updated to increase lows into the upper 60s to around 70. Also introduced a slight chance of thunderstorms over areas south and east of the Concho Valley. The main threat from storms will be strong gusty winds and deadly lightning. && .AVIATION... /06Z TAFS/ MVFR stratus developing in the Hill Country was likely be delayed by extensive mid/upper cloudiness over the region. However it should eventually reach the I-10 corridor and areas around Brady around 9Z. Stratus deck may make it to San Angelo, though confidence is not high, so kept it as a scattered layer. Isolated dry line thunderstorm activity possible late Wednesday afternoon and evening, but best chance of storms will be after 06Z/Thursday, so left thunder out of this TAF issuance. && .PREV DISCUSSION... /ISSUED 633 PM CDT TUE MAY 6 2014/ AVIATION... /00Z TAFS/ Stratus with MVFR CIGS returns along the I-10 corridor around 9Z and spreads northward. A few patches of stratus may affect KSJT, but most should stay south. Winds will increase mid morning and further increase late afternoon as lee trough strengthens. Isolated dry line thunderstorm possible late Wednesday afternoon, but coverage too low to put TAFS. PREV DISCUSSION... /ISSUED 357 PM CDT TUE MAY 6 2014/ SHORT TERM... (Tonight and Wednesday) Expect hot and dry weather this afternoon and a chance of thunderstorms Wednesday afternoon. A dryline was located along a Fredrick, OK to Abilene to Sonora line at 20Z. Latest SPC mesoanaylsis indicates weak instability(MLCAPES 500 to 1000 J/KG) ahead of the dryline over the eastern part of our area. The remaining convective inhibition or low level inversion may be erased for isolated storms to develop mainly after 22Z across the northern Heartland and eastern Big Country. the HRRR convective allowing model has been showing isolated storms developing the past several hourly runs. High LCLs and an inverted-v sounding profiles favor strong gusty winds and hail with the stronger storms. Also, storms will produce dangerous cloud to ground lightning. Any storms that do develop will exit the area or quickly dissipate by 02Z. The rest of tonight will see low level southerly flow and low level moisture returning. The dryline will retreat to just west of our area by 12Z Wednesday. Lows tonight will be in the 60s to around 70. For Wednesday, the morning looks quiet with low clouds across much of the area. Low clouds will break up across much of the area by early afternoon. Aloft, a strong upper level trough will be located over the southern Rockies. A dryline will move slowly east to along a Haskell to San Angelo line by late in the afternoon. Low level convergence along the dryline and increasing large scale ascent from approaching trough will cause isolated to scattered thunderstorms to develop across much of West Central Texas mainly after 20Z. The combination of some instability(MLCAPES of 1500 to 2000 J/KG) and 0-6KM bulk shear of 45 to 50 knots, will result in some storms being severe. The main threats will be large hail, damaging winds and dangerous cloud to ground lightning. Highs will be 90 to 95. LONG TERM... (Wednesday night through next Tuesday) By Wednesday night, the large upper level trough currently near Las Vegas will be moving east through the desert southwest toward west Texas. This feature will bring synoptic scale upward motion with it into west and west central Texas from Wednesday evening into Thursday. Have generally bumped PoPs up again with this forecast, as we get closer to the event, and become more confident in thunderstorms taking place. In addition, have added the mention of severe thunderstorms to the forecast for Wednesday evening, carrying over the mention from the afternoon. With 0-6km bulk shear values of 40-55 knots, and SFC and mixed layer CAPE values ranging from near 1000 J/kg to as high as 1500 J/kg, there will be enough instability, and storm organization carried over into the evening hours for the threat of severe weather to be possible. As with the previous period, the main concerns will be large hail and damaging winds. As the event evolves overnight, the instability will wane, and thus have the mention of severe weather in the forecast only through 06Z. In addition to the severe weather possibility, some of the thunderstorms will contain heavy rainfall, and localized flooding will be possible, mainly in urban areas. On Thursday, we will likely continue to see a broken line of showers with embedded thunderstorms for the eastern half of the area, especially during the morning hours as steering flow remain southwest, making the exit of precipitation a little slow. Severe weather concern will be limited with this mainly morning activity. One more weak shortwave will move through the area Friday afternoon and evening, possibly providing one more shot at precipitation for southeastern areas Friday afternoon and night. Expect temperatures to continue to be above normal through the forecast period. Thursday and Friday will be the cooler days averaging mainly in the upper 80s to lower 90s. Temperatures will quickly warm back into the mid 90s for the weekend. Have not made any significant changes beyond the end of this week as there is still a lot of uncertainty associated with the forecast for early next week. The GFS is much more progressive and weaker with an upper level system, sending a cold front into the area Sunday night whereas the ECMWF is slower and stronger, and waits until Monday evening to send a cold front into the area. FIRE WEATHER... Critical fire weather conditions are expected this afternoon and early evening, generally west of a Haskell to Bronte line. A Red Flag Warning is in effect until 9 PM across the western Big Country and Northern Concho Valley due to RH values of 7 to 12 percent and southwest winds around 20 mph. Also, ERC values are at record levels across this area. An increase in low level moisture late tonight should result in RH values recovering to 60 to 80 percent across much of West Central Texas. Elevated fire weather conditions are expected Wednesday afternoon west of a Haskell to Ozona line due to RH values of 15 to 25 percent and wind speeds of 15 mph. Thunderstorms will bring potential wetting rains across mainly northern and eastern areas Wednesday night and Thursday. && .PRELIMINARY POINT TEMPS/POPS... Abilene 69 94 67 87 61 / 5 30 50 30 10 San Angelo 71 94 68 91 57 / 5 20 40 20 10 Junction 71 91 70 87 66 / 10 20 50 40 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 04/24
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
359 PM EDT WED MAY 7 2014 .SYNOPSIS... A WEAK FRONTAL BOUNDARY ACROSS SOUTHWEST VIRGINIA INTO WESTERN NORTH CAROLINA TONIGHT WILL RETURN NORTHWARD THURSDAY AS HIGH PRESSURE ALOFT BUILDS ACROSS THE REGION. VERY WARM CONDITIONS THURSDAY AND FRIDAY UNDER THE UPPER RIDGE WILL GIVE WAY TO SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS AN UPPER TROUGH APPROACHES THE REGION FROM THE WEST. && .NEAR TERM /THROUGH THURSDAY/... AS OF 350 PM EDT WEDNESDAY... REGIONAL WSR-88D IMAGES SHOWED DISSIPATING COMPLEX OF SHOWERS AND THUNDERSTORMS NORTH OF OUR REGION MOVING EAST ACROSS NORTHERN VA TO THE ATLANTIC COAST. SATELLITE PICTURE INDICATED HIGH CLOUDS PUSHING SOUTH ACROSS THE REGION WITH CU FIELDS MAINLY ACROSS THE MOUNTAINS. FRONTAL BOUNDARY REMAINS ACROSS OUR REGION THIS AFTERNOON INTO TONIGHT. CAP IS STILL HOLDING DESPITE THE SOLAR HEATING...BUT IT IS WEAKENING. HRRR GENERATE A FEW SHOWERS ACROSS THE SOUTHWEST HIGH TERRAIN BUT KEPT MOST OF THE STORMS NORTH OF OUR AREA. THE NAM AND GFS GENERATE SOME STORMS ACROSS THE NORTH THIS AFTERNOON INTO THIS EVENING. THUS..ALLOWED FOR JUST A FEW SHOWERS THIS EVENING IN THE HIGHER TERRAIN. UPPER RIDGE IS BUILDING INTO THE REGION FROM THE WEST...AND BAROCLINIC ZONE NORTHWARD TONIGHT. WITH LOW LEVEL MOISTURE AND LIGHT WINDS ELECTED TO ADD THE MENTION OF FOG OVERNIGHT. WENT WITH LOW TEMPERATURES CLOSE TO THE ADJMAVBC WITH READINGS FROM THE LOWER 50S IN THE NORTH TO THE LOWER 60S ACROSS THE RIDGES. THURSDAY WILL BE A VERY WARM DAY AS AN UPPER LEVEL RIDGE PASSES ACROSS THE APPALACHIAN CHAIN. THE COMBINATION OF VERY WARM AIR BUILDING IN FROM THE SOUTHWEST...COMBINED WITH ABUNDANT SUNSHINE AND DOWNSLOPE WIND FLOW WILL ALLOW AFTERNOON TEMPERATURES TO TOP IN THE LOWER 90S IN THE PIEDMONT...WHILE THE MOUNTAINS CAN EXPECT MID 80S TO UPPER 70S...WITH COOLER TEMPERATURES AT HIGHER ELEVATIONS. A STRONG LAYER OF STABLE AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL HINDER SHOWERS AND THUNDERSTORMS DEVELOPMENT. HIGH TEMPERATURE RECORDS IN THE MOUNTAINS ARE IN JEOPARDY THURSDAY REFER TO CLIMATE SECTION. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 330 PM EDT WEDNESDAY... RIDGE OVERHEAD THU NIGHT WILL GET PUSHED EAST BY TROUGH DIGGING ACROSS THE MIDDLE OF THE COUNTRY WITH ASSOCIATED SHORTWAVES PUSHING INTO THE OHIO VALLEY FRIDAY. FRONTAL BOUNDARY WORKING TOWARD THE OHIO VALLEY FRIDAY WILL BE BRINGING INCREASED MOISTURE INTO THE MOUNTAINS. THINK ENOUGH CONVERGENCE AND UPPER SUPPORT FOR SHOWERS AND THUNDERSTORMS TO BE ISOLATED TO SCATTERED. ANOTHER WARM DAY WITH HIGHS IN THE 80S. FRI NIGHT-SAT...FRONT SLOWS DOWN AS IT BECOMES MORE PARALLEL TO UPPER FLOW WHICH BECOMES MORE ZONAL. SHOWERS AND STORMS EDGE CLOSER AND BY SATURDAY MORNING THE WRN CWA SHOULD SEE A GOOD THREAT FOR SHOWERS. DO NOT EXPECT TO SEE A SVR THREAT GIVEN TIMING AND BEST UPPER SUPPORT STAYS NORTH OVER THE GREAT LAKES. SATURDAY WILL BE COOLER WITH CLOUD COVER AND SCATTERED SHOWERS/ISOLATED STORMS WITH 70S WEST TO AROUND 80 EAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 330 PM EDT WEDNESDAY... OPERATIONAL RUNS OF THE GFS/ECMWF CONTINUE TO DIFFER ON THE PATTERN NEXT WEEK...WITH THE ECWMF ENSEMBLES OVERALL PRETTY CONSISTENT. THE UPPER PATTERN GOES FROM A SOUTHEAST RIDGE TO SOUTHWEST FLOW ALOFT WITH 5H TROUGH DIGGING THRU THE CENTRAL PART OF THE COUNTRY MONDAY AND BECOMING NEGATIVELY TILTED BY MIDWEEK. MAIN FRONT TO MOVE ACROSS OUR REGION WEDNESDAY. FOR THIS FORECAST ENOUGH CONVERGENCE WITH LEE TROUGH...UPPER DIVERGENCE WITH SHORTWAVE OVER THE GULF COAST TO KEEP CHANCE POPS IN SUNDAY. WILL SEE DIURNAL TYPE CYCLE FOR POPS INTO MONDAY WITH SFC HIGH SITUATED OFF THE SE COAST WITH WARM/STATIONARY FRONTAL BOUNDARY LINGERING OVER NOVA/NORTHERN WV. HUMIDITY EXPECTED TO BE ELEVATED AS WELL. AS WE HEAD TOWARD TUE-WED FRONTAL BOUNDARY AND UPPER LEVEL FORCING WILL CLOSE IN WITH BETTER THREAT OF SHOWERS AND STORMS. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... AS OF 135 PM EDT WEDNESDAY... MVFR SCT TO BKN CLOUDS EXPECTED THIS AFTERNOON INTO TONIGHT. MORNING LOW CLOUDS ERODING ACROSS NORTH CAROLINA. CU FIELDS DEVELOPING ACROSS THE MOUNTAINS THIS AFTERNOON. AN ISOLATED SHOWER OR THUNDERSTORM IS POSSIBLE ESPECIALLY ACROSS THE HIGHEST TERRAIN ALONG THE SOUTHERN BLUE RIDGE THIS AFTERNOON INTO TONIGHT. HIGH CLOUDS WILL PUSH SOUTH ACROSS NORTHEAST PORTION OF CWA FROM THUNDERSTORMS TO OUR NORTH THIS AFTERNOON INTO THIS EVENING. AS WEDGE CONTINUES TO ERODE OVERNIGHT...EXPECT RETURN TO VFR CONDITIONS ALL AREAS...ALTHOUGH SOME MVFR BR MAY DEVELOP LATE NIGHT/EARLY THU MORNING AT LWB/LYH/BCB. THIS AFTERNOON WINDS SHOULD GENERALLY BE ESE-SE MOST SITES AT SPEEDS OF 5-8KTS...BECOMING CALM/VRB03KT AROUND 00Z THU...THEN SW AFTER 12Z THU. ON THURSDAY...THE FRONT LIFTS TO THE NORTH WITH WARMER AIR ALOFT PUTTING A CAP ON ANY CONVECTION UNDER VFR CU FIELDS. MEDIUM TO HIGH CONFIDENCE IN CEILINGS AND VISIBILITIES. HIGH CONFIDENCE IN WIND DIR/SPD THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... BY LATE FRIDAY A COLD FRONT WILL APPROACH FROM THE WEST...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE MOUNTAINS DURING THE EVENING. BETTER CHANCE FOR SUB-VFR AT TIMES SAT AFTERNOON/EVENING WITH THE FRONT SLOWLY MOVING EAST AND DEEPER MOISTURE IN PLACE. BOUNDARY MAY WASH OUT UPON CROSSING THE AREA BY SUNDAY WITH MAINLY VFR CONDITIONS EXPECTED OUTSIDE OF OCNL MVFR IN SCATTERED AFTERNOON/EVENING SHRA. && .CLIMATE... HIGH TEMPERATURE RECORDS IN THE MOUNTAINS ARE IN JEOPARDY THURSDAY. MAY GET CLOSE IN THE EAST. CURRENT RECORDS FOR MAY 8TH... ROANOKE......94/1940 LYNCHBURG....94/1940 DANVILLE.....92/1986 BLACKSBURG...85/2000 BLUEFIELD....84/2004 LEWISBURG....82/2000 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...KK/RAB NEAR TERM...KK SHORT TERM...WP LONG TERM...WP AVIATION...KK/RAB CLIMATE...PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
142 PM EDT WED MAY 7 2014 .SYNOPSIS... HIGH PRESSURE ALONG THE EAST COAST WILL KEEP A RELATIVELY COOL AIRMASS ACROSS MUCH OF THE REGION TODAY. A WEAK FRONTAL BOUNDARY ACROSS SOUTHWEST VIRGINIA INTO WESTERN NORTH CAROLINA WILL RETURN NORTHWARD THURSDAY AS HIGH PRESSURE ALOFT BUILDS ACROSS THE REGION. VERY WARM CONDITIONS THURSDAY AND FRIDAY UNDER THE UPPER RIDGE WILL GIVE WAY TO SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS AN UPPER TROUGH APPROACHES THE REGION FROM THE WEST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1130 AM EDT WEDNESDAY... REGIONAL WSR-88D LOOP SHOWED MAIN COMPLEX OF THUNDERSTORMS NORTH OF OUR REGION ACROSS NORTHERN VA AND WESTERN MD. THIS IS WHERE THE BEST INSTABILITY IS LOCATED NORTH OF FRONTAL BOUNDARY. SATELLITE IMAGES SHOWED LOW CLOUDS ERODING ACROSS OUR CWA. DECREASED CLOUD COVER FOR THIS AFTERNOON AND INCREASED TEMPERATURES AND HIGH TEMPERATURES FOR THIS AFTERNOON. HAVE A GOOD AFTERNOON. AS OF 943 AM EDT WEDNESDAY... SATELLITE LOOP SHOWED THAT LOW LEVEL CLOUDS MIXING OUT THIS MORNING...WITH THE RICHES CLOUDS ACROSS SOUTHERN PORTIONS OF CWA. ADJUSTED CLOUD COVER FOR THIS MORNING INTO THIS AFTERNOON WITH LATEST TRENDS. LOOKS LIKE THE NAM AND GFS ARE OVERDONE WITH CONVECTION THIS AFTERNOON FOR CWA. PREFER THE HRRR WITH STORMS STAYING TO THE NORTH OF OUR AREA. MATCHES UP NICELY WITH SWODY1 GENERAL THUNDERSTORM OUTLOOK FOR TODAY. THIS SEEM REASONABLE WITH UPPER RIDGE BUILDING INTO THE REGION FROM THE WEST...AND BAROCLINIC ZONE NORTHWARD TODAY. CAPPED ALOFT WAS QUITE HEALTHY ESPECIALLY ACROSS SOUTHERN PORTIONS OF CWA. WITH PATCHY CLOUDINESS...AND COOL WEDGE WILL HOLD WITH FORECAST HIGH TEMPERATURES FOR THIS AFTERNOON. MAY NEED TO RAISE HIGHS DEPENDING ON CLOUD COVER LATE THIS MORNING INTO THIS AFTERNOON. ONLY MINOR ADJUSTMENTS IN TEMPERATURES AND DEW POINTS IN ISC GRIDS. MORE CHANGES LATER.... AS OF 420 AM EDT WEDNESDAY... QUASI-STATIONARY FRONT OF THE PAST SEVERAL DAYS MOVED BACK WEST AGAIN TUESDAY EVENING...AND EARLY THIS MORNING WAS LOCATED FROM NEAR LWB-BLF-TNB. AS EXPECTED LOW CLOUDS ARE DEVELOPING EAST OF THE FRONT...ESPECIALLY IN UPSLOPE AREAS ALONG THE BLUE RIDGE FROM SIF-ROA-LYH. FAIRLY FAVORABLE WEDGE PATTERN WITH BUILDING RIDGE ALOFT AND SFC HIGH PRESSURE ANCHORED FROM QUEBEC SOUTHEASTWARD TO OFF THE DELMARVA PENINSULA. THUS...EXPECT MUCH OF THE CWA TO REMAIN MOSTLY CLOUDY AND RELATIVELY COOL TODAY WITH EASTERLY MARITIME FLOW. MOST AREAS WILL SEE HIGHS IN THE UPPER 60S TO LOWER 70S EAST OF THE ALLEGHANY FRONT...MID 70S ACROSS THE NC COUNTIES...APPROACHING 80 IN FAR SW VA/SOUTHERN WV...WHICH WILL EITHER REMAIN WEST OF THE WEDGE BOUNDARY OR MOVE BACK INTO THE WARM SECTOR DURING THE AFTERNOON. WITH RESPECT TO CONVECTION...THE CHANCE FOR SUCH IN OUR CWA IS DECREASING. WITH UPPER RIDGE BUILDING INTO THE REGION FROM THE WEST...BAROCLINIC ZONE WILL BE PUSHED NORTHWARD...AND TODAY SHOULD RESIDE FROM NORTHERN WV INTO NORTHERN VA. WITH WARMING TEMPS ALOFT AND A COOL STABLE LAYER AT THE SFC...EXPECT LITTLE IF ANY CONVECTION. IN THE FAR SW WHERE IT WILL BE MORE UNSTABLE IT WILL BE CAPPED ALOFT...SO NOTHING EXPECTED THERE EITHER. HOWEVER...A FEW SHOWERS OR SPRINKLES CANNOT BE TOTALLY RULED OUT...ESPECIALLY THROUGH MID-DAY...BETWEEN THE BLUE RIDGE AND THE ALLEGHANY FRONT ALONG-NORTH OF I-64...SUCH AS WE HAVE SEEN FROM TIME-TO-TIME OVERNIGHT. WITH ALL OF THESE FACTORS IN MIND...HAVE OPTED NOT TO MENTION TSRA FOR THE NEAR TERM. MODEL INSTABILITY IS GROSSLY OVER ESTIMATED AND MY THINKING IS CONSISTENT WITH SPCS LACK OF EVEN A GENERAL THUNDER AREA FOR OUR CWA TODAY. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 330 AM EDT WEDNESDAY... THURSDAY IS SHAPING UP TO BE DRY AND VERY WARM AS AN UPPER LEVEL RIDGE PASSES ACROSS THE APPALACHIAN CHAIN. THE COMBINATION OF VERY WARM AIR BUILDING IN FROM THE SOUTHWEST...COMBINED WITH ABUNDANT SUNSHINE AND GENERAL DOWNSLOPE WIND FLOW WILL ALLOW AFTERNOON TEMPERATURES TO TOP OUT JUST ABOVE 90 IN A FEW AREAS ACROSS THE SOUTHSIDE...WHILE THE MOUNTAINS CAN EXPECT MID 80S TO UPPER 70S...WITH COOLER TEMPERATURES AT HIGHER ELEVATIONS. A STRONG LAYER OF STABLE AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL KEEP SHOWERS AND THUNDERSTORMS AT BAY. SOUTHWESTERLY FLOW WILL ALSO RESULT IN WARM OVERNIGHT LOWS...WITH MID 50S TO LOW 60S EXPECTED AREAWIDE. UPPER RIDGING WILL SHIFT EAST ON FRIDAY...RESULTING IN SLIGHTLY MORE INSTABILITY...PARTICULARLY DURING LATE AFTERNOON AND EARLY EVENING. CONTINUED SOUTHWESTERLY FLOW WILL RESULT IN ANOTHER WARM DAY. HOWEVER...WITH INCREASING CLOUD COVER AHEAD OF ANOTHER APPROACHING FRONT...EXPECT FRIDAY AFTERNOON HIGHS TO BE SLIGHTLY COOLER THAN THOSE ON THURSDAY. STILL...WILL BE LOOKING AT 80S FOR A MAJORITY OF THE FORECAST REGION. EXPECT A FEW SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS THE MOUNTAINS WITH MAXIMUM DAYTIME HEATING. INSTABILITY APPEARS TO BE LIMITED...AND WITH ONLY VERY WEAK UPPER LEVEL DISTURBANCES EXPECTED...CONVECTION SHOULD REMAIN SPOTTY AND DISORGANIZED. LONG RANGE MODELS APPEAR IN BETTER AGREEMENT THIS MORNING THAT UPPER LEVEL RIDGING ACROSS THE EAST WILL GIVE WAY TO A MORE ZONAL WEST TO EAST FLOW ON SATURDAY MORNING. THE ZONAL FLOW WILL CAUSE THE APPROACHING COLD FRONT TO LOSE ITS COLD AIR PUSH...FORCING IT TO STALL WEST OF OUR AREA. MINOR UPPER LEVEL DISTURBANCES WILL PASS ACROSS THE REGION THROUGH THE DAY...RESULTING IN ROUNDS OF SHOWER AND SOME THUNDERSTORM ACTIVITY...WITH THE BRUNT OF THE RAINFALL OCCURRING ACROSS THE MOUNTAINS. REGARDLESS...INSTABILITY APPEARS TO BE MARGINAL...AND THE POTENTIAL FOR STRONG THUNDERSTORMS WILL BE REMOTE. INCREASED CLOUD COVER AND SPOTTY RAINFALL WILL MAKE FOR COOLER AFTERNOON TEMPERATURES...WITH HIGHS REACHING INTO THE 70S MOST LOCATIONS...POSSIBLY TOUCHING 80 AROUND DANVILLE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 330 PM EDT TUESDAY... VARIABILITY IN THE MODELS LEADS TO A LOW CONFIDENCE FORECAST FOR SUNDAY THROUGH TUESDAY. THE GFS FAVORS A MORE ZONAL FLOW ALOFT NEXT WEEK VS. A MORE AMPLIFIED ECMWF SOLUTION. FOR SUNDAY...THE GFS INDICATES A LOW AMPLITUDE RIDGE BUILDING IN FROM THE WEST...WITH ANOTHER FRONT COMING THROUGH ABOUT TUESDAY EVENING. THE ECMWF IS MORE AMPLIFIED WITH THE RIDGING...CAUSING THE SURFACE FRONT TO GET CAUGHT UNDERNEATH THE RIDGE AND HOLD WEST OF OUR AREA. THIS RESULTS IN A WETTER SOLUTION OVERALL FOR THE LONG TERM PERIOD. SINCE THE CURRENT PATTERN FAVORS A MORE AMPLIFIED SOLUTION WILL ENTERTAIN A FORECAST CLOSER TO THE ECMWF. AS SUCH TRENDED THE FORECAST CLOUDIER AND COOLER TO START THE WEEK...TEMPERATURES MONDAY AND TUESDAY WILL BE CLOSER TO NORMAL ALONG WITH A CHANCE OF SHOWERS. BY MID WEEK...FLOW ALOFT SHOULD BECOME SOUTHWEST WITH ANOTHER WARM SURGE PRIOR TO ANY FRONTAL PASSAGE IN THE LATE TUESDAY...THURSDAY TIME FRAME. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 135 PM EDT WEDNESDAY... MVFR SCT TO BKN CLOUDS EXPECTED THIS AFTERNOON INTO TONIGHT. MORNING LOW CLOUDS ERODING ACROSS NORTH CAROLINA. CU FIELDS DEVELOPING ACROSS THE MOUNTAINS THIS AFTERNOON. AN ISOLATED SHOWER OR THUNDERSTORM IS POSSIBLE ESPECIALLY ACROSS THE HIGHEST TERRAIN ALONG THE SOUTHERN BLUE RIDGE THIS AFTERNOON INTO TONIGHT. HIGH CLOUDS WILL PUSH SOUTH ACROSS NORTHEAST PORTION OF CWA FROM THUNDERSTORMS TO OUR NORTH THIS AFTERNOON INTO THIS EVENING. AS WEDGE CONTINUES TO ERODE OVERNIGHT...EXPECT RETURN TO VFR CONDITIONS ALL AREAS...ALTHOUGH SOME MVFR BR MAY DEVELOP LATE NIGHT/EARLY THU MORNING AT LWB/LYH/BCB. THIS AFTERNOON WINDS SHOULD GENERALLY BE ESE-SE MOST SITES AT SPEEDS OF 5-8KTS...BECOMING CALM/VRB03KT AROUND 00Z THU...THEN SW AFTER 12Z THU. ON THURSDAY...THE FRONT LIFTS TO THE NORTH WITH WARMER AIR ALOFT PUTTING A CAP ON ANY CONVECTION UNDER VFR CU FIELDS. MEDIUM TO HIGH CONFIDENCE IN CEILINGS AND VISIBILITIES. HIGH CONFIDENCE IN WIND DIR/SPD THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... BY LATE FRIDAY A COLD FRONT WILL APPROACH FROM THE WEST...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE MOUNTAINS DURING THE EVENING. BETTER CHANCE FOR SUB-VFR AT TIMES SAT AFTERNOON/EVENING WITH THE FRONT SLOWLY MOVING EAST AND DEEPER MOISTURE IN PLACE. BOUNDARY MAY WASH OUT UPON CROSSING THE AREA BY SUNDAY WITH MAINLY VFR CONDITIONS EXPECTED OUTSIDE OF OCNL MVFR IN SCATTERED AFTERNOON/EVENING SHRA. && .CLIMATE... HIGH TEMPERATURE RECORDS IN THE MOUNTAINS ARE IN JEOPARDY THURSDAY. MAY GET CLOSE IN THE EAST. CURRENT RECORDS FOR MAY 8TH... ROANOKE......94/1940 LYNCHBURG....94/1940 DANVILLE.....92/1986 BLACKSBURG...85/2000 BLUEFIELD....84/2004 LEWISBURG....82/2000 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...RAB NEAR TERM...KK/RAB SHORT TERM...NF LONG TERM...NF/PM AVIATION...KK/RAB CLIMATE...PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1132 AM EDT WED MAY 7 2014 .SYNOPSIS... HIGH PRESSURE ALONG THE EAST COAST WILL KEEP A RELATIVELY COOL AIRMASS ACROSS MUCH OF THE REGION TODAY. A WEAK FRONTAL BOUNDARY ACROSS SOUTHWEST VIRGINIA INTO WESTERN NORTH CAROLINA WILL RETURN NORTHWARD THURSDAY AS HIGH PRESSURE ALOFT BUILDS ACROSS THE REGION. VERY WARM CONDITIONS THURSDAY AND FRIDAY UNDER THE UPPER RIDGE WILL GIVE WAY TO SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS AN UPPER TROUGH APPROACHES THE REGION FROM THE WEST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1130 AM EDT WEDNESDAY... REGIONAL WSR-88D LOOP SHOWED MAIN COMPLEX OF THUNDERSTORMS NORTH OF OUR REGION ACROSS NORTHERN VA AND WESTERN MD. THIS IS WHERE THE BEST INSTABILITY IS LOCATED NORTH OF FRONTAL BOUNDARY. SATELLITE IMAGES SHOWED LOW CLOUDS ERODING ACROSS OUR CWA. DECREASED CLOUD COVER FOR THIS AFTERNOON AND INCREASED TEMPERATURES AND HIGH TEMPERATURES FOR THIS AFTERNOON. HAVE A GOOD AFTERNOON. AS OF 943 AM EDT WEDNESDAY... SATELLITE LOOP SHOWED THAT LOW LEVEL CLOUDS MIXING OUT THIS MORNING...WITH THE RICHES CLOUDS ACROSS SOUTHERN PORTIONS OF CWA. ADJUSTED CLOUD COVER FOR THIS MORNING INTO THIS AFTERNOON WITH LATEST TRENDS. LOOKS LIKE THE NAM AND GFS ARE OVERDONE WITH CONVECTION THIS AFTERNOON FOR CWA. PREFER THE HRRR WITH STORMS STAYING TO THE NORTH OF OUR AREA. MATCHES UP NICELY WITH SWODY1 GENERAL THUNDERSTORM OUTLOOK FOR TODAY. THIS SEEM REASONABLE WITH UPPER RIDGE BUILDING INTO THE REGION FROM THE WEST...AND BAROCLINIC ZONE NORTHWARD TODAY. CAPPED ALOFT WAS QUITE HEALTHY ESPECIALLY ACROSS SOUTHERN PORTIONS OF CWA. WITH PATCHY CLOUDINESS...AND COOL WEDGE WILL HOLD WITH FORECAST HIGH TEMPERATURES FOR THIS AFTERNOON. MAY NEED TO RAISE HIGHS DEPENDING ON CLOUD COVER LATE THIS MORNING INTO THIS AFTERNOON. ONLY MINOR ADJUSTMENTS IN TEMPERATURES AND DEW POINTS IN ISC GRIDS. MORE CHANGES LATER.... AS OF 420 AM EDT WEDNESDAY... QUASI-STATIONARY FRONT OF THE PAST SEVERAL DAYS MOVED BACK WEST AGAIN TUESDAY EVENING...AND EARLY THIS MORNING WAS LOCATED FROM NEAR LWB-BLF-TNB. AS EXPECTED LOW CLOUDS ARE DEVELOPING EAST OF THE FRONT...ESPECIALLY IN UPSLOPE AREAS ALONG THE BLUE RIDGE FROM SIF-ROA-LYH. FAIRLY FAVORABLE WEDGE PATTERN WITH BUILDING RIDGE ALOFT AND SFC HIGH PRESSURE ANCHORED FROM QUEBEC SOUTHEASTWARD TO OFF THE DELMARVA PENINSULA. THUS...EXPECT MUCH OF THE CWA TO REMAIN MOSTLY CLOUDY AND RELATIVELY COOL TODAY WITH EASTERLY MARITIME FLOW. MOST AREAS WILL SEE HIGHS IN THE UPPER 60S TO LOWER 70S EAST OF THE ALLEGHANY FRONT...MID 70S ACROSS THE NC COUNTIES...APPROACHING 80 IN FAR SW VA/SOUTHERN WV...WHICH WILL EITHER REMAIN WEST OF THE WEDGE BOUNDARY OR MOVE BACK INTO THE WARM SECTOR DURING THE AFTERNOON. WITH RESPECT TO CONVECTION...THE CHANCE FOR SUCH IN OUR CWA IS DECREASING. WITH UPPER RIDGE BUILDING INTO THE REGION FROM THE WEST...BAROCLINIC ZONE WILL BE PUSHED NORTHWARD...AND TODAY SHOULD RESIDE FROM NORTHERN WV INTO NORTHERN VA. WITH WARMING TEMPS ALOFT AND A COOL STABLE LAYER AT THE SFC...EXPECT LITTLE IF ANY CONVECTION. IN THE FAR SW WHERE IT WILL BE MORE UNSTABLE IT WILL BE CAPPED ALOFT...SO NOTHING EXPECTED THERE EITHER. HOWEVER...A FEW SHOWERS OR SPRINKLES CANNOT BE TOTALLY RULED OUT...ESPECIALLY THROUGH MID-DAY...BETWEEN THE BLUE RIDGE AND THE ALLEGHANY FRONT ALONG-NORTH OF I-64...SUCH AS WE HAVE SEEN FROM TIME-TO-TIME OVERNIGHT. WITH ALL OF THESE FACTORS IN MIND...HAVE OPTED NOT TO MENTION TSRA FOR THE NEAR TERM. MODEL INSTABILITY IS GROSSLY OVER ESTIMATED AND MY THINKING IS CONSISTENT WITH SPCS LACK OF EVEN A GENERAL THUNDER AREA FOR OUR CWA TODAY. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 330 AM EDT WEDNESDAY... THURSDAY IS SHAPING UP TO BE DRY AND VERY WARM AS AN UPPER LEVEL RIDGE PASSES ACROSS THE APPALACHIAN CHAIN. THE COMBINATION OF VERY WARM AIR BUILDING IN FROM THE SOUTHWEST...COMBINED WITH ABUNDANT SUNSHINE AND GENERAL DOWNSLOPE WIND FLOW WILL ALLOW AFTERNOON TEMPERATURES TO TOP OUT JUST ABOVE 90 IN A FEW AREAS ACROSS THE SOUTHSIDE...WHILE THE MOUNTAINS CAN EXPECT MID 80S TO UPPER 70S...WITH COOLER TEMPERATURES AT HIGHER ELEVATIONS. A STRONG LAYER OF STABLE AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL KEEP SHOWERS AND THUNDERSTORMS AT BAY. SOUTHWESTERLY FLOW WILL ALSO RESULT IN WARM OVERNIGHT LOWS...WITH MID 50S TO LOW 60S EXPECTED AREAWIDE. UPPER RIDGING WILL SHIFT EAST ON FRIDAY...RESULTING IN SLIGHTLY MORE INSTABILITY...PARTICULARLY DURING LATE AFTERNOON AND EARLY EVENING. CONTINUED SOUTHWESTERLY FLOW WILL RESULT IN ANOTHER WARM DAY. HOWEVER...WITH INCREASING CLOUD COVER AHEAD OF ANOTHER APPROACHING FRONT...EXPECT FRIDAY AFTERNOON HIGHS TO BE SLIGHTLY COOLER THAN THOSE ON THURSDAY. STILL...WILL BE LOOKING AT 80S FOR A MAJORITY OF THE FORECAST REGION. EXPECT A FEW SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS THE MOUNTAINS WITH MAXIMUM DAYTIME HEATING. INSTABILITY APPEARS TO BE LIMITED...AND WITH ONLY VERY WEAK UPPER LEVEL DISTURBANCES EXPECTED...CONVECTION SHOULD REMAIN SPOTTY AND DISORGANIZED. LONG RANGE MODELS APPEAR IN BETTER AGREEMENT THIS MORNING THAT UPPER LEVEL RIDGING ACROSS THE EAST WILL GIVE WAY TO A MORE ZONAL WEST TO EAST FLOW ON SATURDAY MORNING. THE ZONAL FLOW WILL CAUSE THE APPROACHING COLD FRONT TO LOSE ITS COLD AIR PUSH...FORCING IT TO STALL WEST OF OUR AREA. MINOR UPPER LEVEL DISTURBANCES WILL PASS ACROSS THE REGION THROUGH THE DAY...RESULTING IN ROUNDS OF SHOWER AND SOME THUNDERSTORM ACTIVITY...WITH THE BRUNT OF THE RAINFALL OCCURRING ACROSS THE MOUNTAINS. REGARDLESS...INSTABILITY APPEARS TO BE MARGINAL...AND THE POTENTIAL FOR STRONG THUNDERSTORMS WILL BE REMOTE. INCREASED CLOUD COVER AND SPOTTY RAINFALL WILL MAKE FOR COOLER AFTERNOON TEMPERATURES...WITH HIGHS REACHING INTO THE 70S MOST LOCATIONS...POSSIBLY TOUCHING 80 AROUND DANVILLE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 330 PM EDT TUESDAY... VARIABILITY IN THE MODELS LEADS TO A LOW CONFIDENCE FORECAST FOR SUNDAY THROUGH TUESDAY. THE GFS FAVORS A MORE ZONAL FLOW ALOFT NEXT WEEK VS. A MORE AMPLIFIED ECMWF SOLUTION. FOR SUNDAY...THE GFS INDICATES A LOW AMPLITUDE RIDGE BUILDING IN FROM THE WEST...WITH ANOTHER FRONT COMING THROUGH ABOUT TUESDAY EVENING. THE ECMWF IS MORE AMPLIFIED WITH THE RIDGING...CAUSING THE SURFACE FRONT TO GET CAUGHT UNDERNEATH THE RIDGE AND HOLD WEST OF OUR AREA. THIS RESULTS IN A WETTER SOLUTION OVERALL FOR THE LONG TERM PERIOD. SINCE THE CURRENT PATTERN FAVORS A MORE AMPLIFIED SOLUTION WILL ENTERTAIN A FORECAST CLOSER TO THE ECMWF. AS SUCH TRENDED THE FORECAST CLOUDIER AND COOLER TO START THE WEEK...TEMPERATURES MONDAY AND TUESDAY WILL BE CLOSER TO NORMAL ALONG WITH A CHANCE OF SHOWERS. BY MID WEEK...FLOW ALOFT SHOULD BECOME SOUTHWEST WITH ANOTHER WARM SURGE PRIOR TO ANY FRONTAL PASSAGE IN THE LATE TUESDAY...THURSDAY TIME FRAME. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... AS OF 745 AM EDT WEDNESDAY... LOW CLOUDS DEVELOPED AS EXPECTED...MAINLY EAST OF THE ALLEGHANY FRONT. UNCERTAINTY REMAINS CONCERNING DURATION OF LOW CLOUDS AND ASSOCIATED MVFR TO IFR CIGS AND MVFR VSBYS. BACK DOOR FRONT SHIFTED BACK TO THE WEST AFTER SUNSET TUESDAY...AND NOW APPEARS TO BE BACK INTO FAR SW VA NEAR MKJ. E-ENE WINDS EVIDENT ACROSS MOST OF THE CWA. ALL MODELS POINT TOWARD THE COOLER...EASTERLY MARITIME FLOW DOMINATING MUCH OF THE DAYTIME TODAY AS OPPOSED TO YESTERDAY. THIS WILL OCCUR AS FAIRLY TYPICAL WEDGE SUPPORTING PATTERN OF UPPER RIDGE BUILDING OVER SFC WEDGE/COLD AIR DAMMING. CIGS IN LOW CLOUD AREAS GENERALLY IN THE 015-040 RANGE...SO A VARIETY OF MVFR TO VFR. SOME IFR CIGS NOTED ACROSS NORTH CENTRAL NC. LOWEST CIGS RIGHT ALONG UPSLOPE AREAS OF BLUE RIDGE...WITH AREAS FURTHER EAST...E.G. LYH/DAN...SEEING MOSTLY VFR CIGS. AMENDMENTS/ADJUSTMENTS WILL LIKELY CONTINUE THROUGH THE MORNING. BY AFTERNOON...EXPECT GRADUAL IMPROVEMENT OF CIGS...WITH MOSTLY VFR CONDITIONS WEST OF THE ALLEGHANY FRONT. MID-CLOUD DECK WILL LIFT NORTH THROUGH THE DAY WITH THE WARM FRONT. VSBYS SHOULD REMAIN MOSTLY VFR FROM THIS POINT THROUGH THE DAY. AS WEDGE CONTINUES TO ERODE OVERNIGHT...EXPECT RETURN TO VFR CONDITIONS ALL AREAS...ALTHOUGH SOME MVFR BR MAY DEVELOP LATE NIGHT/EARLY THU MORNING AT LWB/LYH/BCB. WINDS TODAY SHOULD GENERALLY BE ESE-SE MOST SITES AT SPEEDS OF 5-8KTS...BECOMING CALM/VRB03KT AROUND 00Z THU...THEN SW AFTER 12Z THU. LOW TO MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN VSBYS THROUGH 15Z...THEN HIGH CONFIDENCE IN VFR VSBYS. HIGH CONFIDENCE IN WIND DIR/SPD THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... THURSDAY...THE FRONT LIFTS TO THE NORTH WITH WARMER AIR ALOFT PUTTING A CAP ON ANY CONVECTION UNDER VFR CU FIELDS. BY LATE FRIDAY A COLD FRONT WILL APPROACH FROM THE WEST...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE MOUNTAINS DURING THE EVENING. BETTER CHANCE FOR SUB-VFR AT TIMES SAT AFTERNOON/EVENING WITH THE FRONT SLOWLY MOVING EAST AND DEEPER MOISTURE IN PLACE. BOUNDARY MAY WASH OUT UPON CROSSING THE AREA BY SUNDAY WITH MAINLY VFR CONDITIONS EXPECTED OUTSIDE OF OCNL MVFR IN SCATTERED AFTERNOON/EVENING SHRA. && .CLIMATE... HIGH TEMPERATURE RECORDS IN THE MOUNTAINS ARE IN JEOPARDY THURSDAY. MAY GET CLOSE IN THE EAST. CURRENT RECORDS FOR MAY 8TH... ROANOKE......94/1940 LYNCHBURG....94/1940 DANVILLE.....92/1986 BLACKSBURG...85/2000 BLUEFIELD....84/2004 LEWISBURG....82/2000 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...RAB/KK NEAR TERM...KK/RAB SHORT TERM...NF LONG TERM...NF/PM AVIATION...JH/RAB CLIMATE...PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
944 AM EDT WED MAY 7 2014 .SYNOPSIS... HIGH PRESSURE ALONG THE EAST COAST WILL KEEP A RELATIVELY COOL...CLOUDY AIR MASS ACROSS MUCH OF THE REGION TODAY. A WEAK FRONTAL BOUNDARY ACROSS SOUTHWEST VIRGINIA INTO WESTERN NORTH CAROLINA WILL RETURN NORTHWARD THURSDAY AS HIGH PRESSURE ALOFT BUILDS ACROSS THE REGION. VERY WARM CONDITIONS THURSDAY AND FRIDAY UNDER THE UPPER RIDGE WILL GIVE WAY TO SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS AN UPPER TROUGH APPROACHES THE REGION FROM THE WEST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 943 AM EDT WEDNESDAY... SATELLITE LOOP SHOWED THAT LOW LEVEL CLOUDS MIXING OUT THIS MORNING...WITH THE RICHES CLOUDS ACROSS SOUTHERN PORTIONS OF CWA. ADJUSTED CLOUD COVER FOR THIS MORNING INTO THIS AFTERNOON WITH LATEST TRENDS. LOOKS LIKE THE NAM AND GFS ARE OVERDONE WITH CONVECTION THIS AFTERNOON FOR CWA. PREFER THE HRRR WITH STORMS STAYING TO THE NORTH OF OUR AREA. MATCHES UP NICELY WITH SWODY1 GENERAL THUNDERSTORM OUTLOOK FOR TODAY. THIS SEEM REASONABLE WITH UPPER RIDGE BUILDING INTO THE REGION FROM THE WEST...AND BAROCLINIC ZONE NORTHWARD TODAY. CAPPED ALOFT WAS QUITE HEALTHY ESPECIALLY ACROSS SOUTHERN PORTIONS OF CWA. WITH PATCHY CLOUDINESS...AND COOL WEDGE WILL HOLD WITH FORECAST HIGH TEMPERATURES FOR THIS AFTERNOON. MAY NEED TO RAISE HIGHS DEPENDING ON CLOUD COVER LATE THIS MORNING INTO THIS AFTERNOON. ONLY MINOR ADJUSTMENTS IN TEMPERATURES AND DEW POINTS IN ISC GRIDS. MORE CHANGES LATER.... AS OF 420 AM EDT WEDNESDAY... QUASI-STATIONARY FRONT OF THE PAST SEVERAL DAYS MOVED BACK WEST AGAIN TUESDAY EVENING...AND EARLY THIS MORNING WAS LOCATED FROM NEAR LWB-BLF-TNB. AS EXPECTED LOW CLOUDS ARE DEVELOPING EAST OF THE FRONT...ESPECIALLY IN UPSLOPE AREAS ALONG THE BLUE RIDGE FROM SIF-ROA-LYH. FAIRLY FAVORABLE WEDGE PATTERN WITH BUILDING RIDGE ALOFT AND SFC HIGH PRESSURE ANCHORED FROM QUEBEC SOUTHEASTWARD TO OFF THE DELMARVA PENINSULA. THUS...EXPECT MUCH OF THE CWA TO REMAIN MOSTLY CLOUDY AND RELATIVELY COOL TODAY WITH EASTERLY MARITIME FLOW. MOST AREAS WILL SEE HIGHS IN THE UPPER 60S TO LOWER 70S EAST OF THE ALLEGHANY FRONT...MID 70S ACROSS THE NC COUNTIES...APPROACHING 80 IN FAR SW VA/SOUTHERN WV...WHICH WILL EITHER REMAIN WEST OF THE WEDGE BOUNDARY OR MOVE BACK INTO THE WARM SECTOR DURING THE AFTERNOON. WITH RESPECT TO CONVECTION...THE CHANCE FOR SUCH IN OUR CWA IS DECREASING. WITH UPPER RIDGE BUILDING INTO THE REGION FROM THE WEST...BAROCLINIC ZONE WILL BE PUSHED NORTHWARD...AND TODAY SHOULD RESIDE FROM NORTHERN WV INTO NORTHERN VA. WITH WARMING TEMPS ALOFT AND A COOL STABLE LAYER AT THE SFC...EXPECT LITTLE IF ANY CONVECTION. IN THE FAR SW WHERE IT WILL BE MORE UNSTABLE IT WILL BE CAPPED ALOFT...SO NOTHING EXPECTED THERE EITHER. HOWEVER...A FEW SHOWERS OR SPRINKLES CANNOT BE TOTALLY RULED OUT...ESPECIALLY THROUGH MID-DAY...BETWEEN THE BLUE RIDGE AND THE ALLEGHANY FRONT ALONG-NORTH OF I-64...SUCH AS WE HAVE SEEN FROM TIME-TO-TIME OVERNIGHT. WITH ALL OF THESE FACTORS IN MIND...HAVE OPTED NOT TO MENTION TSRA FOR THE NEAR TERM. MODEL INSTABILITY IS GROSSLY OVER ESTIMATED AND MY THINKING IS CONSISTENT WITH SPCS LACK OF EVEN A GENERAL THUNDER AREA FOR OUR CWA TODAY. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 330 AM EDT WEDNESDAY... THURSDAY IS SHAPING UP TO BE DRY AND VERY WARM AS AN UPPER LEVEL RIDGE PASSES ACROSS THE APPALACHIAN CHAIN. THE COMBINATION OF VERY WARM AIR BUILDING IN FROM THE SOUTHWEST...COMBINED WITH ABUNDANT SUNSHINE AND GENERAL DOWNSLOPE WIND FLOW WILL ALLOW AFTERNOON TEMPERATURES TO TOP OUT JUST ABOVE 90 IN A FEW AREAS ACROSS THE SOUTHSIDE...WHILE THE MOUNTAINS CAN EXPECT MID 80S TO UPPER 70S...WITH COOLER TEMPERATURES AT HIGHER ELEVATIONS. A STRONG LAYER OF STABLE AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL KEEP SHOWERS AND THUNDERSTORMS AT BAY. SOUTHWESTERLY FLOW WILL ALSO RESULT IN WARM OVERNIGHT LOWS...WITH MID 50S TO LOW 60S EXPECTED AREAWIDE. UPPER RIDGING WILL SHIFT EAST ON FRIDAY...RESULTING IN SLIGHTLY MORE INSTABILITY...PARTICULARLY DURING LATE AFTERNOON AND EARLY EVENING. CONTINUED SOUTHWESTERLY FLOW WILL RESULT IN ANOTHER WARM DAY. HOWEVER...WITH INCREASING CLOUD COVER AHEAD OF ANOTHER APPROACHING FRONT...EXPECT FRIDAY AFTERNOON HIGHS TO BE SLIGHTLY COOLER THAN THOSE ON THURSDAY. STILL...WILL BE LOOKING AT 80S FOR A MAJORITY OF THE FORECAST REGION. EXPECT A FEW SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS THE MOUNTAINS WITH MAXIMUM DAYTIME HEATING. INSTABILITY APPEARS TO BE LIMITED...AND WITH ONLY VERY WEAK UPPER LEVEL DISTURBANCES EXPECTED...CONVECTION SHOULD REMAIN SPOTTY AND DISORGANIZED. LONG RANGE MODELS APPEAR IN BETTER AGREEMENT THIS MORNING THAT UPPER LEVEL RIDGING ACROSS THE EAST WILL GIVE WAY TO A MORE ZONAL WEST TO EAST FLOW ON SATURDAY MORNING. THE ZONAL FLOW WILL CAUSE THE APPROACHING COLD FRONT TO LOSE ITS COLD AIR PUSH...FORCING IT TO STALL WEST OF OUR AREA. MINOR UPPER LEVEL DISTURBANCES WILL PASS ACROSS THE REGION THROUGH THE DAY...RESULTING IN ROUNDS OF SHOWER AND SOME THUNDERSTORM ACTIVITY...WITH THE BRUNT OF THE RAINFALL OCCURRING ACROSS THE MOUNTAINS. REGARDLESS...INSTABILITY APPEARS TO BE MARGINAL...AND THE POTENTIAL FOR STRONG THUNDERSTORMS WILL BE REMOTE. INCREASED CLOUD COVER AND SPOTTY RAINFALL WILL MAKE FOR COOLER AFTERNOON TEMPERATURES...WITH HIGHS REACHING INTO THE 70S MOST LOCATIONS...POSSIBLY TOUCHING 80 AROUND DANVILLE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 330 PM EDT TUESDAY... VARIABILITY IN THE MODELS LEADS TO A LOW CONFIDENCE FORECAST FOR SUNDAY THROUGH TUESDAY. THE GFS FAVORS A MORE ZONAL FLOW ALOFT NEXT WEEK VS. A MORE AMPLIFIED ECMWF SOLUTION. FOR SUNDAY...THE GFS INDICATES A LOW AMPLITUDE RIDGE BUILDING IN FROM THE WEST...WITH ANOTHER FRONT COMING THROUGH ABOUT TUESDAY EVENING. THE ECMWF IS MORE AMPLIFIED WITH THE RIDGING...CAUSING THE SURFACE FRONT TO GET CAUGHT UNDERNEATH THE RIDGE AND HOLD WEST OF OUR AREA. THIS RESULTS IN A WETTER SOLUTION OVERALL FOR THE LONG TERM PERIOD. SINCE THE CURRENT PATTERN FAVORS A MORE AMPLIFIED SOLUTION WILL ENTERTAIN A FORECAST CLOSER TO THE ECMWF. AS SUCH TRENDED THE FORECAST CLOUDIER AND COOLER TO START THE WEEK...TEMPERATURES MONDAY AND TUESDAY WILL BE CLOSER TO NORMAL ALONG WITH A CHANCE OF SHOWERS. BY MID WEEK...FLOW ALOFT SHOULD BECOME SOUTHWEST WITH ANOTHER WARM SURGE PRIOR TO ANY FRONTAL PASSAGE IN THE LATE TUESDAY...THURSDAY TIME FRAME. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 745 AM EDT WEDNESDAY... LOW CLOUDS DEVELOPED AS EXPECTED...MAINLY EAST OF THE ALLEGHANY FRONT. UNCERTAINTY REMAINS CONCERNING DURATION OF LOW CLOUDS AND ASSOCIATED MVFR TO IFR CIGS AND MVFR VSBYS. BACK DOOR FRONT SHIFTED BACK TO THE WEST AFTER SUNSET TUESDAY...AND NOW APPEARS TO BE BACK INTO FAR SW VA NEAR MKJ. E-ENE WINDS EVIDENT ACROSS MOST OF THE CWA. ALL MODELS POINT TOWARD THE COOLER...EASTERLY MARITIME FLOW DOMINATING MUCH OF THE DAYTIME TODAY AS OPPOSED TO YESTERDAY. THIS WILL OCCUR AS FAIRLY TYPICAL WEDGE SUPPORTING PATTERN OF UPPER RIDGE BUILDING OVER SFC WEDGE/COLD AIR DAMMING. CIGS IN LOW CLOUD AREAS GENERALLY IN THE 015-040 RANGE...SO A VARIETY OF MVFR TO VFR. SOME IFR CIGS NOTED ACROSS NORTH CENTRAL NC. LOWEST CIGS RIGHT ALONG UPSLOPE AREAS OF BLUE RIDGE...WITH AREAS FURTHER EAST...E.G. LYH/DAN...SEEING MOSTLY VFR CIGS. AMENDMENTS/ADJUSTMENTS WILL LIKELY CONTINUE THROUGH THE MORNING. BY AFTERNOON...EXPECT GRADUAL IMPROVEMENT OF CIGS...WITH MOSTLY VFR CONDITIONS WEST OF THE ALLEGHANY FRONT. MID-CLOUD DECK WILL LIFT NORTH THROUGH THE DAY WITH THE WARM FRONT. VSBYS SHOULD REMAIN MOSTLY VFR FROM THIS POINT THROUGH THE DAY. AS WEDGE CONTINUES TO ERODE OVERNIGHT...EXPECT RETURN TO VFR CONDITIONS ALL AREAS...ALTHOUGH SOME MVFR BR MAY DEVELOP LATE NIGHT/EARLY THU MORNING AT LWB/LYH/BCB. WINDS TODAY SHOULD GENERALLY BE ESE-SE MOST SITES AT SPEEDS OF 5-8KTS...BECOMING CALM/VRB03KT AROUND 00Z THU...THEN SW AFTER 12Z THU. LOW TO MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN VSBYS THROUGH 15Z...THEN HIGH CONFIDENCE IN VFR VSBYS. HIGH CONFIDENCE IN WIND DIR/SPD THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... THURSDAY...THE FRONT LIFTS TO THE NORTH WITH WARMER AIR ALOFT PUTTING A CAP ON ANY CONVECTION UNDER VFR CU FIELDS. BY LATE FRIDAY A COLD FRONT WILL APPROACH FROM THE WEST...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE MOUNTAINS DURING THE EVENING. BETTER CHANCE FOR SUB-VFR AT TIMES SAT AFTERNOON/EVENING WITH THE FRONT SLOWLY MOVING EAST AND DEEPER MOISTURE IN PLACE. BOUNDARY MAY WASH OUT UPON CROSSING THE AREA BY SUNDAY WITH MAINLY VFR CONDITIONS EXPECTED OUTSIDE OF OCNL MVFR IN SCATTERED AFTERNOON/EVENING SHRA. && .CLIMATE... HIGH TEMPERATURE RECORDS IN THE MOUNTAINS ARE IN JEOPARDY THURSDAY. MAY GET CLOSE IN THE EAST. CURRENT RECORDS FOR MAY 8TH... ROANOKE......94/1940 LYNCHBURG....94/1940 DANVILLE.....92/1986 BLACKSBURG...85/2000 BLUEFIELD....84/2004 LEWISBURG....82/2000 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...RAB NEAR TERM...KK/RAB SHORT TERM...NF LONG TERM...NF/PM AVIATION...JH/RAB CLIMATE...PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
210 AM EDT WED MAY 7 2014 .SYNOPSIS... A FRONT WILL REMAIN STALLED ACROSS OUR REGION TONIGHT THROUGH WEDNESDAY. AN UPPER RIDGE WILL BUILD OVER THE REGION THURSDAY... RESULTING IN WARMER AND DRIER CONDITIONS. HIGH PRESSURE WILL GIVE WAY TO A SLOW MOVING FRONTAL SYSTEM LATE FRIDAY INTO SATURDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 900 PM EDT TUESDAY... EVENING RNK SOUNDING SHOWING QUITE A BIT OF LOW LEVEL INSTABILITY WITH CAPES NEAR 2K BEING CAPPED ALOFT VIA A DECENT INVERSION JUST ABOVE 7H. HOWEVER LOW LEVELS REMAIN DRY WITH BETTER SURFACE COOLING ONGOING AS THE EASTERLY FLOW HAS NOW FLOPPED BACK TO AS FAR WEST AS THE BLUE RIDGE. IN ADDITION...SUPPORT ALOFT LACKING ATTM TO ERODE THE CAP ...WHILE THE SURFACE BOUNDARY REMAINS TO THE SW WHERE THE AIR REMAINS ARID ON THE WEST SIDE OF THE FRONT OVER THE NW NC RIDGES. THUS LITTLE TO TRIGGER CONVECTION THERE. HOWEVER DEWPOINTS LOOK TO SLOWLY RECOVER NORTHWARD EAST OF THE BLUE RIDGE OVERNIGHT WITH A WEAK IMPULSE SLIDING ACROSS LATE IN THE NW FLOW ALOFT. MODELS REMAIN OVERDONE WITH CONVECTION BUT APPEARS A WINDOW POSSIBLE DURING THE NEXT FEW HOURS INTO THE EARLY MORNING HOURS OVER THE FAR NORTH TO SEE A FEW BANDS OF SHRA/TSRA WITH THIS FAINT FEATURE. GIVEN CURRENT LACK OF COVERAGE BASICALLY REMOVED POPS EARLY THIS EVENING...AND CUT BACK TO MOSTLY ISOLATED TO CHANCE COVERAGE NORTH OF HIGHWAY 460 DURING THE OVERNIGHT. OTRW EXPECT LOW CLOUDS TO FILL BACK IN ESPCLY EAST AS THE WEDGE DEEPENS AGAIN WITH MAINLY CLEAR SKIES OVER THE WEST/SW. SOME PATCHY FOG ALSO POSSIBLE OUT EAST AND IN THE VALLEYS BUT QUITE SPOTTY. ADJUSTED LOWS DOWN SOME BLUE RIDGE EAST PER EASTERLY FLOW AND BUMPED UP WEST GIVEN SLOW TO FALL READINGS AND MORE OF A LIGHT WEST WIND THROUGH DAYBREAK. UPDATE AS OF 630 PM EDT TUESDAY... EARLY UPDATE TO REMOVE GOING POPS ACROSS THE REGION INTO THIS EVENING GIVEN LOW LEVEL DRY AIR IN PLACE PER OBS/MSAS AND LACK OF MUCH CONVERGENCE OR SHRA. STILL POTENTIAL FOR ISOLATED COVERAGE TO BREAK THE CAP ALOFT SEEN OFF EARLIER SOUNDINGS BUT CURRENT CLOUD FIELDS AND LATEST MODELS SUGGEST MAY BE LATER WHEN A WEAK IMPULSE ALOFT RIDES IN FROM THE NW. OTRW STILL SEEING QUITE A SPREAD IN TEMPS FROM THE WEDGING IN THE NE TO THE VERY WARM TEMPS OVER THE SW WHERE THE AIR IS VERY DRY PER HUMIDITY LEVELS BELOW 20 PERCENT. WILL LEAVE IN CURRENT CHANCE POPS AFTER SUNSET WHEN MAY SEE MOISTURE POOL ALONG THE BLUE RIDGE OTRW RUNNING DRY OVER THE NEXT COUPLE OF HOURS PER THE LATEST HRRR. PREVIOUS DISCUSSION AS OF 330 PM EDT TUESDAY... FRONTAL BOUNDARY REMAINS ACROSS REGION THROUGH TONIGHT. SHORTWAVE COMES OVER UPPER RIDGE INTO THE FORECAST AREA LATE TONIGHT. DESPITE SOLAR HEATING...STRONG CAP THIS AFTERNOON HINDERING CONVECTION DEVELOPMENT. WEAK DPVA ASSOCIATED WITH SHORTWAVE MAY BE ABLE TO OVERCOME THE HEALTHY CAP. LIKE YESTERDAY...SWODY1 ADDED THE MENTION OF A SEE TEXT FOR ISOLATED SEVERE THUNDERSTORMS WITH A HAIL AND WIND THREAT FOR VIRGINIA. MODIFIED FCST SOUNDINGS SUGGEST RELATIVELY COLD AIR ALOFT AND GOOD LAPSE RATES FOR THIS AFTERNOON INTO TONIGHT. RNK WRFARW DEVELOPS SOME CONVECTION THIS AFTERNOON ACROSS THE NORTH TO NORTHEAST CORNER OF CWA AND DROP SOUTHEAST. HRRR SHOWED SOME ISOLATED CONVECTION ACROSS THE NORTH THIS EVENING INTO TONIGHT. GFS AND ECMWF STILL SHOWING SCATTERED CONVECTION ACROSS THE NORTH WITH WAA TONIGHT. WILL KEEP ISOLATED TO SCATTERED CONVECTION IN FOR THIS EVENING INTO TONIGHT ACROSS THE NORTH. BUT...HAVE CONCERNS THAT CAP MAY HOLD AND LIMITED CONVECTION. PLAYED LOW TEMPERATURES CLOSE TO ADJMAVBC WITH READINGS FROM LOWER 50S IN THE NORTHERN MOUNTAINS TO THE UPPER 50S IN THE PIEDMONT. THE H8 WARN FRONT LIFTS NORTH ON WEDNESDAY. BEST LIFT AND INSTABILITY IS ACROSS THE NORTH FOR WEDNESDAY. GOOD LAPSE RATE AND ELEVATED INSTABILITY SUPPORT MENTION OF SHOWERS AND ISOLATED ACROSS THE NORTH. FLOW BECOME SOUTHERLY IN THE SOUTH ON WEDNESDAY AND CAP IS EVEN STRONGER...ELECTED TO KEEP MENTION OF STORMS OUT OF SOUTHERN PORTIONS OF FA. HIGH TEMPERATURES ON WEDNESDAY CHALLENGING FOR THE NORTHEASTERN THIRD OF THE CWA WITH CLOUDS AND POTENTIAL CONVECTION. HIGH TEMPERATURES ON WEDNESDAY WILL VARY FROM AROUND 70 IN THE NORTH TO THE LOWER TO MID 80S IN THE FAR SOUTHWEST AND ALONG THE FOOTHILLS OF THE SOUTHERN BLUE RIDGE MOUNTAINS. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... AS OF 330 PM EDT TUESDAY... TEMPERATURES WELL ABOVE NORMAL TO FINISH OFF THE WORK WEEK. HIGH AMPLITUDE UPPER LEVEL FLOW WILL SUBJECT FORECAST AREA TO A SURGE OF VERY WARM AIR THURSDAY AND FRIDAY. AN UPPER LEVEL RIDGE OF HIGH PRESSURE IS EXPECTED TO AMPLIFY INTO THE 582 TO 588 DM RANGE OVER THE EASTERN CONUS...AXIS RUNNING NORTH-SOUTH FROM ONTARIO CANADA TO FLORIDA. THE GREATEST AMPLITUDE IS EXPECTED THURSDAY... THEN BREAKING DOWN FRIDAY AS A MID CONUS TROF MOVES EAST. 850 MB TEMPS THURSDAY ARE PROGGED NEAR 18 DEG C. THIS ALONE WILL PROMOTE TEMPERATURES WELL INTO THE 80S. AN ADDED BOOST WILL OCCUR FROM ADIABATIC WARMING...WESTERLY WINDS RESULTING IN COMPRESSIONAL HEATING AS THE AIR PASSES OVER AND DOWN THE MTNS. THE NET EFFECT WILL BE TEMPERATURES WHICH WILL TEST THE 90 DEGREE MARK ON THE EAST SIDE OF THE MOUNTAINS THURSDAY...AND TO A LESSER DEGREE FRIDAY AS THE WINDS BACK MORE TOWARD THE SOUTHWEST AHEAD OF THE APPROACHING MID CONUS TROUGH. STRONG SUBSIDENCE THURSDAY WILL SQUELCH ANY CHANCE OF SHOWER ACTIVITY YIELDING A MOSTLY SUNNY DAY. AS THE SUBSIDENCE WEAKENS FRIDAY...SHOULD SEE A BIT MORE CUMULUS...BUT THINK ANY THREAT OF SHOWER OR STORM ACTIVITY WILL HOLD OFF UNTIL LATE UNLESS AN OUTFLOW BOUNDARY MOVES EAST OF THE MAIN MID CONUS FRONT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 330 PM EDT TUESDAY... VARIABILITY IN THE MODELS LEADS TO A LOW CONFIDENCE FORECAST... ESPECIALLY NEXT WEEK. SATURDAY IS THE ONLY DAY WHERE THE MODELS REMOTELY LOOK SIMILAR...THEN THEY DIVERGE RESULTING IN DIFFERING SOLUTIONS FOR SUNDAY THROUGH TUESDAY. THE GFS IS PROGRESSIVE AND AND FAVORS ZONAL FLOW ALOFT NEXT WEEK VS. THE MORE AMPLIFIED ECMWF. FOR SATURDAY BOTH MODELS BRING SURGE OF MOISTURE INTO THE AREA AHEAD OF APPROACHING SURFACE FRONT. THIS RESULTS IN LIKELIHOOD OF SHOWERS AND POSSIBLE THUNDERSTORMS...ESP ACROSS THE MOUNTAINS. THE GFS THEN PUSHES THE FRONT THROUGH THE AREA QUICKLY WITH ANOTHER FRONT COMING THROUGH ABOUT TUESDAY. THE ECMWF SLOWS SATURDAYS FRONT WITH TROUGHING LINGERING THROUGH THE WEEKEND...FOLLOWED BY HIGHER AMPLITUDE RIDGING ALOFT EARLY NEXT WEEK WITH THE SURFACE FRONT GETTING CAUGHT UNDERNEATH THE RIDGE. THIS RESULTS IN A WETTER SOLUTION THIS WEEKEND FOLLOWED BY A DAY OR TWO OF EASTERLY LOW LEVEL FLOW MONDAY AND TUESDAY UNTIL WE MIX OUT THE MIDDLE OF NEXT WEEK. SINCE THE CURRENT PATTERN FAVORS A MORE AMPLIFIED SOLUTION WILL ENTERTAIN A FORECAST CLOSER TO THE ECMWF. AS SUCH TRENDED THE FORECAST CLOUDIER AND COOLER TO START THE WEEK...TEMPERATURES MONDAY AND TUESDAY CLOSER TO NORMAL ALONG WITH A CHANCE OF SHOWERS. BY MID WEEK...FLOW ALOFT SHOULD BECOME SOUTHWEST WITH ANOTHER WARM SURGE PRIOR TO ANY FRONTAL PASSAGE IN THE WEDNESDAY...THURSDAY TIME FRAME. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 150 AM EDT WEDNESDAY... CONSIDERABLE UNCERTAINTY AT THIS POINT REGARDING THE DEVELOPMENT...TIMING...AND DURATION OF LOW CLOUDS AND ASSOCIATED MVFR TO IFR CIGS AND MVFR VSBYS. BACK DOOR FRONT SHIFTED BACK TO THE WEST AFTER SUNSET...AND NOW APPEARS TO BE BACK INTO FAR SW VA NEAR MKJ. E-ENE WINDS EVIDENT ACROSS MOST OF THE CWA...OR CALM BCB/LWB. ALL MODELS POINT TOWARD THE COOLER...EASTERLY MARITIME FLOW DOMINATING MUCH OF THE DAYTIME TODAY AS OPPOSED TO YESTERDAY. THIS WILL OCCUR AS FAIRLY TYPICAL WEDGE SUPPORTING PATTERN OF UPPER RIDGE BUILDING OVER SFC WEDGE/COLD AIR DAMMING. AS OF NOW...THERE IS LITTLE TO NO EVIDENCE OF LOW CLOUDS ACROSS THE PIEDMONT OR COASTAL PLAIN...BUT WATCHING POTENTIAL DEVELOPMENT OF LOW CLOUDS ALONG THE BLUE RIDGE IN 11-3.9UM SATELLITE...WITH SCT036 JUST NOW APPEARING IN ROA MTR. OTHER PATCHES OF LOW CLOUDS BEGINNING TO APPEAR NEAR LYH. AMENDMENTS/ADJUSTMENTS LIKELY AS LOW CLOUD DEVELOPMENT BECOMES MORE APPARENT. MEANWHILE...EXTENSIVE MID CLOUDS IN THE 080-090 RANGE WILL CONTINUE TO SPREAD ACROSS THE REGION FROM NW-SE IN NW FLOW ALOFT THROUGH THE MORNING HOURS. THEN...THIS BAND OF CLOUDS WILL BEGIN TO LIFT NORTHWARD TOWARD MD/PA AS UPPER RIDGE AMPLIFIES. ONCE THE CLOUD COVER DEVELOPS...MANY QUESTIONS ALSO ARISE AS TO THE DURATION OF SUCH...WITH MOST MODEL GUIDANCE SUGGESTING IT WILL REMAIN IN PLACE THROUGH LATE MORNING/EARLY AFTERNOON AT LEAST. THIS SEEMS TO BE A GOOD COMPROMISE AT THIS POINT...AS SYNOPTIC PATTERN COULD SUPPORT SUCH CLOUDS REMAINING IN PLACE MOST OF THE DAY EAST OF THE BLUE RIDGE. SOME POTENTIAL FOR MVFR VSBYS IN BR LATE NIGHT/EARLY MORNING HOURS...BUT OVERALL POTENTIAL FOR SUCH APPEARS LESS THAN YESTERDAY WITH STRATUS LOOKING MORE LIKELY TODAY. THIS IS SUPPORTED BY BUFKIT SOUNDINGS AS WELL. WINDS TODAY SHOULD GENERALLY BE ESE-SE MOST SITES AT SPEEDS OF 5-8KTS...BECOMING CALM/VRB03KT AROUND 00Z THU. LOW CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN VSBYS THROUGH 15Z...THEN HIGH CONFIDENCE IN VFR VSBYS. HIGH CONFIDENCE IN WIND DIR/SPD THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... THURSDAY...THE FRONT LIFTS TO THE NORTH WITH WARMER AIR ALOFT PUTTING A CAP ON ANY CONVECTION UNDER VFR CU FIELDS. BY LATE FRIDAY A COLD FRONT WILL APPROACH FROM THE WEST...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE MOUNTAINS DURING THE EVENING. BETTER CHANCE FOR SUB-VFR AT TIMES SAT AFTERNOON/EVENING WITH THE FRONT SLOWLY MOVING EAST AND DEEPER MOISTURE IN PLACE. BOUNDARY MAY WASH OUT UPON CROSSING THE AREA BY SUNDAY WITH MAINLY VFR CONDITIONS EXPECTED OUTSIDE OF OCNL MVFR IN SCATTERED AFTERNOON/EVENING SHRA. && .CLIMATE... HIGH TEMPERATURE RECORDS IN THE MOUNTAINS ARE IN JEOPARDY THURSDAY. MAY GET CLOSE IN THE EAST. CURRENT RECORDS FOR MAY 8TH... ROANOKE......94/1940 LYNCHBURG....94/1940 DANVILLE.....92/1986 BLACKSBURG...85/2000 BLUEFIELD....84/2004 LEWISBURG....82/2000 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...KK NEAR TERM...JH/KK SHORT TERM...PM LONG TERM...PM AVIATION...JH/RAB CLIMATE...PM
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
1037 PM CDT THU MAY 8 2014 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE AND NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 1018 PM CDT THU MAY 8 2014 ASIDE FROM A FEW STRONG CELLS MOVG UP THE LAKESHORE...STORMS HAVE BEEN FAIRLY TAME THIS EVG. THERE ARE STILL A FEW SMALL CLUSTERS OF TSTMS OVER FAR EASTERN MN AND FAR NE IA...BUT NO WATCHES OR WARNINGS ARE IN EFFECT FOR UPSTREAM COUNTIES. INSTAB CONTINUES TO WANE...WITH MUCAPE ONLY 200-600 J/KG...BUT WITH STRONG SHEAR...A WARM FRONT OVER CENTRAL WI...AN APPROACHING COLD FRONT AND UPPER TROF...AND A STRONG JET OVERHEAD...CANNOT RULE OUT AN ISOLD SVR TSTM OVERNIGHT. OVERALL THREAT APPEARS TO BE QUITE LOW. HAVE ADJUSTED POPS LOWER TO ACCOUNT FOR THE CURRENT LULL IN PCPN OVER C/EC WI...AND GIVEN UPSTREAM COVERAGE...POPS MAY ALSO BE TOO HIGH FOR THE OVERNIGHT PERIOD. MODELS STILL SUPPORT AN INCREASE IN COVERAGE OVER EASTERN WI AFTER MIDNIGHT...SO DON`T WANT TO LOWER POPS TOO MUCH RIGHT NOW. UPDATE ISSUED AT 711 PM CDT THU MAY 8 2014 CERTAINLY NOT GIVING UP ON THE SEVERE POTENTIAL...BUT CURRENT INDICATIONS SUGGEST THAT A WIDESPREAD EVENT IS NOT LIKELY. MSAS SFC ANALYSIS SHOWED THAT THE WARM FRONT WAS SITUATED FROM WEST CENTRAL WI TO AROUND WISCONSIN RAPIDS...OSHKOSH AND SHEBOYGAN. WIDESPREAD SHOWERS AND TSTMS WERE OCCURRING OVER THE NW HALF OF WI...AND WERE COMPETING FOR THE MARGINAL INSTABILITY (MUCAPE 400-800 J/KG) THAT WAS SITUATED ACROSS THE AREA. TSTMS WERE ALSO BATTLING SOME LINGERING SURFACE-BASED CONVECTIVE INHIBITION. SHEAR IS QUITE STRONG...WITH 0-6 KM BULK SHEAR OF 40-50 KTS...AND 0-3 KM SRH OF 200-400...SO WILL NEED TO MONITOR ANY CELLS THAT BECOME ISOLATED FROM THE ONGOING CLUSTERS. HAVE SEEN SOME INTERESTING STORM MORPHOLOGY... INCLUDING A RECENT CELL SPLIT OVER WC WI...AND RESULTING RIGHT- MOVING SUPERCELL CURRENTLY MOVG THROUGH NW JACKSON COUNTY. DESPITE A LARGE NUMBERS OF ONGOING STORMS OVER MN/IA AND WSTRN WI...THERE ARE RELATIVELY FEW WARNINGS CURRENTLY IN EFFECT. CURRENT INDICATIONS SUGGEST THAT A WIDESPREAD SVR EVENT IS NOT LIKELY...BUT LOCAL SUPERCELLS OR SHORT LINE SEGMENTS MAY POSE AN ISOLD SVR THREAT...LARGE HAIL AND DAMAGING WINDS...THROUGH THE NIGHT. && .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 330 PM CDT THU MAY 8 2014 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE CENTERED OVER EASTERN NEBRASKA AND A WARM FRONT SNAKING ITS WAY FROM JUST SOUTH OF MINNEAPOLIS TO VOLK FIELD TO WEST BEND WISCONSIN. OCCASIONAL LIGHT SHOWERS CONTINUE TO REDEVELOP OVER THE WARM FRONT...WHICH HAVE BEEN MAINLY IMPACTING CENTRAL TO NORTHEAST WISCONSIN. BUT WITH THE FORWARD MOTION OF FRONT AT A SNAILS PACE...INSTABILITY HAS BEEN SLOW TO DEVELOP THIS AFTERNOON. ADDITIONAL LIGHT SHOWERS ASSOCIATED WITH A WEAK SHORTWAVE ARE ALSO MOVING NORTHEAST OVER SOUTHERN WISCONSIN AND WILL MOVE INTO THE FOX VALLEY OVER THE NEXT HOUR OR TWO. THIS WAVE WAS PRODUCING THUNDERSTORMS OVER IOWA EARLIER BUT THOSE HAVE SINCE WEAKENED. THE MAIN SHOW HOWEVER...IS OCCURRING OVER MINNESOTA AND NORTHERN IOWA WHERE STRONG TO SEVERE THUNDERSTORMS ARE OCCURRING ALONG AN UPPER LEVEL FRONT. AS THIS FRONT MOVES EAST...CHANCES OF SEVERE WEATHER ARE THE MAIN FORECAST CONCERN. TONIGHT...LOW PRESSURE WILL BE TRAVELING FROM SOUTHWEST MINNESOTA TO THE WESTERN TIP OF LAKE SUPERIOR. POTENTIAL WILL REMAIN FOR THE WARM FRONT TO BOW NORTHWARD ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN THIS EVENING DUE STRENGTHENING SOUTHERLY FLOW AHEAD OF THE LOW. HOW FAR NORTH IS STILL QUESTIONABLE GIVEN THE SCATTERED SHOWER ACTIVITY...CLOUD COVER...AND EASTERLY FLOW. SHORTWAVE OVER EASTERN IOWA WILL BE LIFTING NE ACROSS THE FORECAST AREA LATE THIS AFTERNOON INTO THE EVENING AT PEAK HEATING. THINKING SCT SHOWERS AND ISOLD TSTORMS WILL CONTINUE TO BE GENERATED FROM THIS WAVE...THAT COULD HELP TO KEEP THE WARM FRONT FARTHER SOUTH THAN MODELS DEPICT. IF ANY STORMS DEVELOP...40-50KTS OF BULK SHEAR WILL SUPPORT A CHANCE OF LARGE HAIL AND DAMAGING WINDS...TO A LESSER EXTENT.. THEN ATTENTION WILL TURN TO SEVERE THUNDERSTORMS WHICH ARE EXPECTED TO DEVELOP LATER THIS AFTERNOON OVER MINNESOTA AND IOWA. THE LATEST SHORT RANGE GUIDANCE SHOWS THIS CONVECTION...IN THE FORM OF LINE SEGMENTS...MOVING INTO CENTRAL AND NORTH-CENTRAL WISCONSIN BY MID-EVENING. CONVERGENCE ALONG THE UPPER LEVEL TROUGH AND UPPER CONVERGENCE WILL PROVIDE DECENT FORCING FOR STORMS TO SUSTAIN THEMSELVES. RATHER DIFFICULT TO GET GAUGE ON INSTABILITY SINCE PROGGED SOUNDINGS ARE EITHER CONTAMINATED WITH CONVECTION OR NOT REPRESENTATIVE OF THE CURRENT ENVIRONMENT. BUT ELEVATED CAPES ARE GENERALLY AROUND 1K J/KG AND THATS A DECENT PLACE TO START. STEEP MID-LEVEL LAPSE RATES AROUND 7 C/KM AND BULK SHEARS IN THE 35-40 KT RANGE WILL SUPPORT A LARGE HAIL AND DAMAGING WIND THREAT. CHANCES OF SEVERE THUNDERSTORMS LOOK BETTER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN AS INSTABILITY DIMINISHES TO THE EAST. THE STORMS SHOULD EXIT LATE OVERNIGHT...BUT ADDITIONAL SPOTTY SHOWERS AND STORMS COULD STILL POP UP ALONG THE TRAILING SURFACE COLD FRONT. TEMPS WILL BE WARM TONIGHT AND RANGE MAINLY FROM THE MID 50S TO LOW 60S. FRIDAY...THE SURFACE COLD FRONT WILL EXIT EASTERN WISCONSIN BY MID-MORNING...AND COULD SEE A PERIOD OF CLEARING OCCUR RIGHT BEHIND THE FRONT AND BENEATH THE DRY SLOT. THEN SHOULD SEE WRAP AROUND MOISTURE PUSH EAST ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN THROUGH THE REST OF THE DAY. PROGGED SOUNDINGS SHOW A STRONG INVERSION AT ABOUT 750MB...SO TONED BACK THE CHANCE OF SHOWERS OVER CENTRAL AND NORTH-CENTRAL WISCONSIN SOME. AIR BEHIND THE FRONT IS NOT ALL THAT COLD...AND KEPT TEMPERATURES RANGING FROM THE LOW 60S WEST TO NEAR 70 NORTHEAST. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 330 PM CDT THU MAY 8 2014 LARGE SCALE MEAN FLOW IS EXPECTED TO BRIEFLY DEAMPLIFY THIS WEEKEND BEFORE RE-AMPLIFYING EARLY NEXT WEEK AS UPR RIDGING OCCURS OVER THE WEST COAST AND AN EWD MOVING LONGWAVE TROF SHIFTS FROM THE CNTRL CONUS TO E-CNTRL NORTH AMERICA. PCPN CHCS TO BE ASSOCIATED FIRST WITH A WEAK IMPULSE EJECTED NE FROM THE MEAN UPR TROF DURING THE LATTER PART OF THE WEEKEND AND THEN EARLY NEXT WEEK WITIH THE APPROACH OF THE UPR TROF AND THE MAIN SFC CYCLONE/ CDFNT. TEMPS ARE FCST TO GO FROM SLIGHTLY ABOVE NORMAL EARLY...TO BELOW NORMAL BY MID-WEEK AS THE MEAN FLOW TURNS NW. ANY LINGERING LIGHT SHWRS OVER NRN WI SHOULD GRADUALLY COME TO AN END FRI EVENING AS THE SHORTWAVE TROF CONTS TO TRACK NE INTO SRN ONTARIO. OTHERWISE...THE MDLS INDICATE A WEAK SFC RDG/RISING UPR HEIGHTS WORKING EAST TOWARD THE WRN GREAT LAKES DURING THE OVRNGT HOURS. DECREASING CLOUDS WITH DIMINISHING WINDS COULD SEND TEMPS DOWN INTO THE 35-40 DEG RANGE NORTH...LWR TO MID 40S SOUTH. SFC RDG MOVES ACROSS NE WI SAT MORNING AND BE TO OUR EAST BY SAT AFTERNOON. MEANWHILE TO OUR WEST...A PIECE OF SHORTWAVE ENERGY IS PROGGED TO EJECT EWD FROM THE DEVELOPING WRN CONUS UPR TROF AND ALREADY BY PUSHING INTO THE UPR MS VALLEY BY 00Z SUNDAY. CLOUDS SHOULD ALREADY BEGIN TO INCREASE INTO CNTRL WI SAT AFTERNOON... BUT WL KEEP PCPN OUT OF THE FCST FOR NOW. MAX TEMPS TO REMAIN A LITTLE ABOVE NORMAL AS WINDS ATTEMPT TO BACK TO THE SOUTH ONCE AGAIN AHEAD OF THE APPROACHING SHORTWAVE TROF. THIS SHORTWAVE TROF TO THEN RACE ACROSS WI SAT NGT...THEREBY BRINGING A CHC OF SHWRS TO THE ENTIRE FCST AREA. INSTABILITY LOOKS MARGINAL RIGHT NOW AND MAY GENERATE AN ISOLATED TSTM OR TWO ACROSS CNTRL/E-CNTRL WI. PLENTY OF CLOUDS/PCPN IN THE VCNTY WL HOLD MIN TEMPS IN THE MID TO UPR 40S NORTH...UPR 40S TO LWR 50 SOUTH. THERE MAY NOW BE A BRIEF BREAK IN THE PCPN CHCS SUNDAY MORNING AS ONCE SHORTWAVE TROF DEPARTS AND THE NEXT SHORTWAVE TROF APPROACHES SUNDAY AFTERNOON. MAY TRY TO SHOW THIS IN THE GRIDS BETTER AND FOCUS THE CHC POPS MORE IN THE AFTERNOON PERIOD. ONE MORE DAY WITH ABOVE NORMAL TEMPS AS READINGS REACH THE MID TO UPR 60S (COOLER NEAR LAKE MI). BY THE START OF THE WORK WEEK...THE LONGWAVE TROF IS WELL- ESTABLISHED OVER THE ROCKIES WITH A DOWNSTREAM UPR RDG OVER E-CNTRL NORTH AMERICA. PREVAILING SW WINDS WL BRING GULF MOISTURE INTO WI ON MON AND LIFT BOTH A SFC LOW AND WRMFNT NORTH INTO WI MON AFTERNOON. FOLLOWED CLOSER TO THE ECMWF MDL HERE AS THE GFS APPEARS TO EJECT THE MAIN UPR TROF TOO QUICKLY INTO THE PLAINS. ANOTHER ROUND OF SHWRS/ISOLATED TSTMS FOR NE WI ON MON WITH MAX TEMPS CLOSER TO NORMAL. A STRONG UPR JET MAX ROUNDS THE BASE OF THE LONGWAVE TROF BY MON EVENING AND RACES NEWD THRU THE MIDWEST TO THE UPR MS VALLEY/WRN GREAT LAKES MON NGT. SHWRS/ISOLATED TSTMS TO CONT MON NGT AS THE CDFNT PUSHES INTO THE REGION. BY TUE...THE UPR TROF DOES MOVE INTO THE PLAINS...BUT THE WRN GREAT LAKES TO BE UNDER THE INFLUENCE OF A DRY SLOT...THUS TUE COULD END UP DRY. MAX TEMPS ON TUE TO AGAIN BE CLOSE TO NORMAL. PCPN CHCS TO THEN INCREASE ONCE AGAIN MID-WEEK AS THE UPR TROF SHIFTS EAST AND SETTLES OVER THE GREAT LAKES. A SERIES OF SHORTWAVES MOVING THRU THE NOW NW FLOW ALOFT WL BRING UNSETTLED WEATHER TO NE WI ON WED AND THU. TEMPS WL DROP TO BELOW NORMAL LEVELS AND WL HAVE TO WATCH N-CNTRL WI WED NGT FOR THE POTENTIAL OF A RAIN/SNOW MIX AS TEMPS FALL INTO THE MID 30S. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1018 PM CDT THU MAY 8 2014 A WARM FRONT WILL LIFT NORTH ACROSS WISCONSIN TONIGHT...FOLLOWED BY A COLD FRONTAL PASSAGE FRIDAY MORNING. SCT-NMRS SHRA/TSTM WILL CONTINUE TO DEVELOP IN ASSOCIATION WITH THESE FRONTAL BOUNDARIES. INSTABILITY IS FAIRLY WEAK...SO THE THREAT OF WIDESPREAD SVR TSTMS IS LOW. MVFR CONDITIONS ARE EXPECTED TO ACCOMPANY ANY TSTM ACTIVITY. THE SHRA/TSRA SHOULD EXIT THE REGION LATE TONIGHT OR EARLY FRIDAY MORNING. MVFR CIGS WILL MOVE INTO NC/C WI IN THE WAKE OF THE COLD FRONT ON FRIDAY...AND SHOULD LINGER FOR MOST OF THE DAY...AND POSSIBLY INTO THE EVENING. SCT SHOWERS ARE ALSO EXPECTED OVER NC/C WI DURING THE AFTERNOON/EARLY EVG. LLWS IS EXPECTED TO END IN EASTERN WI EARLY FRIDAY MORNING. GUSTY SW-W WINDS WILL DEVELOP BEHIND THE FRONT BY MID TO LATE FRIDAY MORNING. && .MARINE... ISSUED AT 1030 PM CDT THU MAY 8 2014 WEB CAMS SHOWED AN INCREASE IN MARINE FOG THIS EVENING...ESPECIALLY TOWARD NORTHPORT. INCREASED THE FOG WORDING IN THE GRIDS/NSH...BUT HELD OFF ON ANY ADVISORIES. && .HYDROLOGY... ISSUED AT 330 PM CDT THU MAY 8 2014 THE ABUNDANT MOISTURE FLOWING NWD INTO THE AREA IS STARTING TO LEAD TO AN INCREASED RISK OF HEAVY RAINS/FLOODING. AT LEAST WE NOW HAVE THE CREST OF THE SNOWMELT WATER THROUGH THE RIVERS...SO CAPACITY FOR RUNOFF FROM RAINS IS GREATER THAN A COUPLE WEEKS AGO. IT/S HARD TO PINPOINT A SPECIFIC RGN OF THE FCST AREA WITH THE GREATEST RISK OF FLOODING...BUT MOST LIKELY COULD OCCUR OVER EAST- CENTRAL WISCONSIN LATER TONIGHT AS STORMS BECOME PARALLEL TO THE MEAN FLOW. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........KIECKBUSCH SHORT TERM.....MPC LONG TERM......KALLAS AVIATION.......KIECKBUSCH MARINE.........KIECKBUSCH HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1021 PM CDT THU MAY 8 2014 .UPDATE... ISSUED AT 1021 PM CDT THU MAY 8 2014 ONE LAST BATCH OF SHOWERS AND THUNDERSTORMS ARE MOVING ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. 0-3KM/MLCAPE HAS BEEN DROPPING OVER THE PAST FEW HOURS AND EXPECT THAT TREND TO CONTINUE THROUGH THE REST OF THE NIGHT. BASED ON 09.01Z RAP ANALYSIS...IT ALSO APPEARS THAT THESE STORMS ARE OCCURRING IN A RELATIVE MINIMUM OF 0-6KM SHEAR AS WELL. THUS...EXPECT THAT STORMS SHOULD REMAIN SUB-SEVERE FROM HERE ON OUT THROUGH THE REST OF TONIGHT. TEMPERATURES WILL REMAIN MILD IN THE UPPER 60S UNTIL THE COLD FRONT PUSHES THROUGH TOWARD DAYBREAK WITH CONVECTION NOT EXPECTED ALONG THIS FRONT. && .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT) ISSUED AT 241 PM CDT THU MAY 8 2014 MAIN FORECAST CONCERNS THIS PERIOD...SHRA/TSRA/SEVERE CHANCES THRU THIS EVENING...LINGERING -SHRA CHANCES FRI...TEMPERATURES. 18Z DATA ANALYSIS HAD A 1000MB LOW OVER NORTHEAST NEB WITH A TROUGH NORTHEAST INTO NORTHWEST WI AND WARM FRONT ARCING EAST ACROSS NORTHERN IA INTO SOUTHERN WI. WARM FRONT CONTINUES TO SEPARATE TO DISTINCT AIRMASSES...70S WITH DEW POINTS IN THE 60S SOUTH OF THE WARM FRONT...60S WITH DEW POINTS IN THE 50S. SB CAPE SOUTH OF THE FRONT IN THE 1500-2500 J/KG RANGE...ELEVATED 500-1000 J/KG NORTH OF THE WARM FRONT. AREA WSR-88D/S SHOWING CONVECTION DEVELOPING/ EXPANDING ACROSS THE SOUTH HALF OF IA...WITH/AHEAD OF SHORTWAVE ENERGY LIFTING UP THE EAST SIDE OF THE MID LEVEL LONG WAVE TROUGH. 08.12Z MODELS GENERALLY INITIALIZED WELL. GFS AGAIN ABOUT 5F HIGH WITH SFC DEW POINTS IN THE MOISTURE PLUME COMING NORTH THRU THE MID MS VALLEY. SOLUTIONS CONVERGING ON A TIGHT COMPROMISE CONSENSUS OF THE EARLIER RUNS AS THE TROUGHING/ENERGY OVER THE ROCKIES/PLAINS LIFTS NORTHEAST THRU THE UPPER MIDWEST TONIGHT THRU FRI NIGHT. STILL SOME LOWER LEVEL DETAIL DIFFERENCES ON CONVECTION EVOLUTION THRU THIS EVENING...BUT AFTER THAT SOLUTIONS QUITE SIMILAR FOR LATER TONIGHT THRU FRI NIGHT AS COOLER/DRIER AIR SPREADS IN BEHIND THE PASSING LOW/COLD FRONT. FCST CONFIDENCE GENERALLY GOOD FOR TONIGHT THRU FRI NIGHT. FOR THE SHORT TERM...AS OF EARLY THIS AFTERNOON...CONVECTIVE SCENARIO FOR LATER THIS AFTERNOON/THIS EVENING REMAINS IN QUESTION. MAIN FOCUS FOR TSRA DEVELOPMENT REMAINS WESTERN IA/SOUTHWEST MN...NEAR THE SFC LOW/TROUGH/FRONTS AND CLOSER TO THE STRONGER SHORTWAVE LIFTING TOWARD EASTERN SD. SHRA/TSRA DEVELOPING/SPREADING NORTH ACROSS IA...ALONG WITH THE CLOUD COVER CONSUMING/LIMITING CAPE EARLY THIS AFTERNOON AND MUDDYING THE TSRA/SEVERE EVOLUTION FOR LATER THIS AFTERNOON/EVENING. LOWER LEVEL CONVERGENCE/FORCING WOULD POINT TO A LINE OF STRONG/SEVERE TSRA DEVELOPING IN WESTERN IA/SOUTHWEST MN THEN LIFTING NORTHEAST ACROSS MN/IA/WI IN THE 21Z-04Z TIME-FRAME. STRONGEST 0-6KM BULK SHEAR OF 30-60KTS IS OVER THE WEST PORTIONS OF THE FCST AREA THIS AFTERNOON AND NORTHWEST PORTIONS OF THE FCST AREA THIS EVENING. SWODY1 SEEMS TO HAVE THE THREATS/RISKS LAYED OUT WELL...BASED ON CONVECTION LIFTING NORTH ACROSS IA NOT INTERFERING TOO MUCH. WILL STAY THE COURSE WITH HIGHEST SHRA/TSRA CHANCES LATER THIS AFTERNOON/EVENING WITH WHAT SHOULD BE A LINE OF CONVECTION MOVING EAST/NORTHEAST ACROSS THE FCST AREA WITH/AHEAD OF THE SFC- 850MB TROUGH/COLD FRONT. SEE SWODY1 FOR MORE DETAILS ON THE SEVERE THREATS THRU THIS EVENING. 925-850MB COLD ADVECTION/DRYING SPREAD RATHER QUICKLY ACROSS THE FCST AREA LATE THIS EVENING/OVERNIGHT AS THE SFC-850MB LOW LIFTS INTO NORTHEAST MN. PW VALUES OF 1 TO 1.5 INCHES AT 00Z FRI ARE HALF THAT BY 12Z FRI. THIS AND PASSAGE OF THE SFC-850MB TROUGH/FRONT SWEEP THE BULK OF THE SHRA/TSRA EAST AND OUT OF THE FCST AREA BY 12Z FRI. ONLY SOME SMALL LINGERING -SHRA CHANCES IN THE EAST/NORTH ENDS OF THE FCST AREA BY 12Z FRI. A SECONDARY SHORTWAVE TO LIFT ACROSS THE AREA FRI AFTERNOON ALONG WITH SOME 850-700MB WRAP-AROUND/ DEFORMATION BAND MOISTURE. DEEPEST OF THIS MOISTURE ACROSS THE NORTH END OF THE FCST AREA...WITH STEEP LOW LEVEL LAPSE RATES AND WEAK INSTABILITY TO ABOUT 750MB. CONTINUED THE SMALL -SHRA CHANCES ACROSS MAINLY THE NORTHEAST 1/3 OF THE FCST AREA THRU FRI AFTERNOON...WHICH BLENDS WELL WITH NEIGHBORING GRIDS. LOSS OF DIURNAL HEATING AND PASSING OF THE SECOND SHORTWAVE QUICKLY PUTS AN END TO THIS AND LEFT FRI NIGHT DRY AS HIGH PRESSURE AND SHORTWAVE RIDGING ALOFT BUILD INTO THE REGION. A COOLER PERIOD TONIGHT THRU FRI NIGHT AS A COOL 925MB AIRMASS SETTLES OVER THE REGION. WINDS/CLOUDS TO KEEP LOWS TONIGHT ABOVE NORMAL. BELOW NORMAL HIGHS FRI UNDER THE COOL 925MB AIRMASS. BELOW NORMAL LOWS FRI NIGHT UNDER MOSTLY CLEAR SKIES/LIGHT WINDS. USED THE MODEL/ENSEMBLE CONSENSUS LOWS/HIGHS FOR TONIGHT THRU FRI NIGHT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 241 PM CDT THU MAY 8 2014 MAIN FORECAST CONCERNS FOR SAT THRU SUN NIGHT...SHRA/TSRA CHANCES THRU THE PERIOD AS MORE TROUGHING/SHORTWAVES TAKE AIM AT THE UPPER MIDWEST. DECENT AGREEMENT AMONG THE 08.12Z MODELS CONTINUES SAT AS THE NEXT STRONGER SHORTWAVE TRACKS INTO MN BY LATE IN THE DAY. IMPROVING CONSENSUS FOR RISING HGTS/SHORTWAVE RIDGING TO BUILD ACROSS THE UPPER MIDWEST LATER SAT/SAT NIGHT...AHEAD OF THE NEXT STRONG/LONG WAVE TROUGH TO DIG INTO THE WESTERN CONUS. TREND CONTINUES STRONGER WITH THIS NEXT TROUGHING INTO THE ROCKIES SAT NIGHT/SUN THEN EJECTING INTO THE WESTERN PLAINS SUN NIGHT. SHORTWAVE RIDGE AXIS THAT BUILDS OVER THE REGION SAT NIGHT QUICKLY MOVES EAST SUN...WITH THE REGION ALREADY UNDER THE INFLUENCE OF SOUTHWEST FLOW ALOFT AHEAD OF THE NEXT TROUGH FOR SUN AFTERNOON/NIGHT. WITH RUN-TO-RUN CONSISTENCY AND THE IMPROVING CONSENSUS...SAT THRU SUN NIGHT FCST CONFIDENCE IS AVERAGE TO GOOD. BREAK BETWEEN SYSTEMS FRI NIGHT INTO SAT IS BRIEF. THE NEXT SHORTWAVE INTO MN LATER SAT QUICKLY SPREADS INCREASING LOWER LEVEL THERMO-DYNAMIC FORCING/LIFT AND INCREASING MOISTURE/THETA-E CONVERGENCE INTO THE FCST AREA THRU THE DAY ON SAT. INITIAL MOISTURE/LIFT GOES INTO SATURATION SAT MORNING...WITH INCREASING SHRA CHANCES INTO SAT AFTERNOON/EVENING AS THE DEEPEST MOISTURE/ STRONGER OF THE LIFT MOVES ACROSS. CARRIED HIGHEST RAIN CHANCES LATER SAT AFTERNOON/EVENING...THE LOWER LATER SAT NIGHT BEHIND THE SFC-850MB TROUGH AXIS. INDICATIONS FOR 250 TO AS MUCH AS 1K J/KG MU CAPE INTO THE AREA AT 00Z SUN SO CONTINUED TSRA MENTION FOR MUCH OF THE FCST AREA SAT AFTERNOON/EVENING. NEXT BREAK BETWEEN SYSTEMS IS ALSO RATHER BRIEF LATER SAT NIGHT/SUN MORNING. WITH THE PROGRESSIVE AND ACTIVE FLOW...THE UPPER MIDWEST IS BACK UNDER SOUTHWEST FLOW ALOFT SUN AFTERNOON/NIGHT...AHEAD OF STRONG MID LEVEL TROUGHING SWINGING THRU THE CENTRAL/SOUTHERN ROCKIES. INCREASING MOISTURE/ LIFT/INSTABILITY QUICKLY SPREAD BACK INTO THE FCST AREA FOR SUN AFTERNOON/NIGHT. PW VALUES IN THE 1 INCH PLUS RANGE BY 00Z MON... AHEAD OF THE NEXT STRONGER SHORTWAVE AND SFC-850MB LOW LIFTING NORTHEAST TOWARD/INTO THE UPPER MIDWEST SUN NIGHT. RAISED SHRA/TSRA CHANCES INTO THE 35-55 PERCENT RANGE SUN AFTERNOON AND 55-70 PERCENT RANGE SUN NIGHT. SOME LOCALLY HEAVY RAINS POSSIBLE SUN NIGHT... DEPENDING ON WHERE THE SFC LOW TRACKS/SFC BOUNDARIES SET UP. DUE TO SOME UNCERTAINTIES WITH WHAT WOULD BE TIMING OF SHRA/TSRA IN/AROUND THE AREA AND CLOUD COVER...USED THE MODEL/ENSEMBLE CONSENSUS HIGHS/ LOWS FOR SAT THRU SUN NIGHT. FOR MONDAY THROUGH THURSDAY.../DAYS 4 TO 7/... MAIN FORECAST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES/RAIN AMOUNTS MON/MON NIGHT...SHRA CHANCES/COOLER TEMPS TUE-THU. MEDIUM RANGE MODEL RUNS OF 08.00Z AND 08.12Z ALL SHOW THE SCENARIO OF STRONG TROUGHING MOVING INTO THE CENTRAL CONUS MON. GFS REMAINS FASTER THAN ECMWF/CAN-GEM. GOOD CONSENSUS FOR THE STRONG TROUGHING TO THEN VERY SLOWLY MOVE INTO/ACROSS THE MID/UPPER MS VALLEY TUE THRU THU...WITH CAN-GEM THE SLOWER/STRONGER OUTLIER BY WED. OVERALL TREND IS SLOWING AND STRONGER WITH THE MID CONUS TROUGHING NEXT WEEK. EVEN WITH SOME DIFFERENCES AMONG THE MODELS FOR MON-THU THE SENSIBLE WEATHER OUTCOMES ARE MORE SIMILAR THAN ONE WOULD USUALLY EXPECT. DAY 4-7 FCST CONFIDENCE IS AVERAGE WITH RAIN CHANCES THRU THE PERIOD BUT GOOD FOR BELOW NORMAL TEMPS FOR TUE-THU. EVEN WITH THE DIFFERENCES ON PROGRESSION OF THE LONG-WAVE TROUGH ON MON...GOOD CONSENSUS FOR A STRONG PIECE OF ENERGY TO BE LIFTING NORTHEAST ACROSS THE UPPER MIDWEST MON/MON NIGHT. RATHER STRONG SFC LOW PROGGED TO ACCOMPANY THIS SHORTWAVE NORTHEAST ACROSS THE REGION MON. WITH PW VALUES OF AN INCH OR MORE...SHRA/TSRA CHANCES IN THE 40-65 PERCENT RANGE MON/MON NIGHT LOOK GOOD. POTENTIAL FOR 1 TO 2 INCHES OF RAIN FROM LATER SUN NIGHT THRU MON NIGHT. COLDER AIR POURS IN FOR TUE THRU THU AS THE THE NORTHERN STREAM PORTION OF THE MID LEVEL TROUGH SETTLES INTO THE UPPER MIDWEST. 850MB TEMPS FALL TO A FEW DEGREES EITHER SIDE OF 0C FOR MUCH OF TUE- THU...SOME 1 TO 2 STANDARD DEVIATIONS BELOW NORMAL. AFTER MORE NORMAL EARLY MAY TEMPS THROUGH THE WEEKEND...TEMPS FOR TUE-THU TREND AROUND 10F BELOW NORMAL. WITH THIS COLD CORE OF AIR ALOFT... STEEP LOW-MID LEVEL LAPSE RATE AND SHORTWAVES ROTATING THRU THE TROUGH WITH ROUNDS OF INCREASED MOISTURE/FORCING...SMALL -SHRA CHANCES MUCH OF THE TUE-THU PERIOD REASONABLE FOR NOW. GIVEN THE TIMING/DETAIL UNCERTAINTIES...DID NOT STRAY MUCH FROM THE MODEL/ ENSEMBLE CONSENSUS HIGHS/LOWS AND RAIN CHANCES FOR DAYS 4-7. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 606 PM CDT THU MAY 8 2014 SCATTERED THUNDERSTORMS ARE DEVELOPING ACROSS PORTIONS OF IOWA INTO SOUTHERN MINNESOTA AND WESTERN WISCONSIN THIS EVENING. GENERAL TREND WILL BE FOR AN INCREASE IN COVERAGE UNTIL MID EVENING...BUT NOT COMPLETELY CLEAR UNTIL FRONTAL PASSAGE AFTER MIDNIGHT. OUTSIDE OF STORMS...MAINLY MID LEVEL CLOUDS WITH SOME HAZE BEING REPORTED. BRIEF PERIODS OF IFR CONDITIONS LIKELY WITH ANY STORM MOVING OVER TAF SITE. THREAT FOR STRONGER TO SEVERE STORMS WILL BE EARLY ON...THEN SHOULD WANE AS THE EVENING PROGRESSES. AS SURFACE LOW LIFTS TO THE NORTHEAST...AND IN THE WAKE OF THE COLD FRONTAL PASSAGE...WRAP AROUND MVFR DECK SLATED TO COME INTO THE TAF SITES EARLY FRIDAY MORNING. THIS SHOULD PERSIST FOR THE REMAINDER OF THE PERIOD. GUSTY WEST TO NORTHWEST WINDS UP TO 25 KTS WILL DEVELOP BY LATE FRIDAY MORNING INTO THE AFTERNOON. && .HYDROLOGY... ISSUED AT 241 PM CDT THU MAY 8 2014 FLOODING CONTINUES ALONG THE MISSISSIPPI RIVER...WITH LOCATIONS CRESTING BETWEEN GENOA AND LANSING. SHOWERS AND THUNDERSTORMS TODAY WILL PRODUCE ANYWHERE FROM A HALF INCH TO ONE INCH OF RAIN. THIS WILL LIKELY SLOW THE FALL FOR LOCATIONS NORTH OF MCGREGOR...AND MAY INCREASE CRESTS SLIGHTLY SOUTH OF MCGREGOR. POTENTIAL FOR 1 TO 2 INCHES OF RAINFALL FROM LATE SUN NIGHT THRU MON EVENING. THIS COULD HAVE ADDITIONAL IMPACTS AND PRODUCE ADDITIONAL RISES ON AREA RIVERS ALREADY RUNNING HIGH FROM THE ABOVE AND MUCH ABOVE NORMAL RAINS OF APRIL. CHECK OUT THE LATEST HYDROLOGIC STATEMENTS FOR THE DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...RRS LONG TERM....RRS AVIATION...ZT HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
937 PM CDT THU MAY 8 2014 .UPDATE... DYNAMICS DO BECOME MORE FAVORABLE FOR SHOWER/THUNDERSTORM DEVELOPMENT LATE TONIGHT. UPPER DIVERGENCE INCREASES AS 250 MB JET MAX OF 100 KNOTS MOVES ACROSS SOUTHERN WISCONSIN. ONE 700 MB JET MAX OF 45 KNOTS HAS ALREADY LIFTED NORTH INTO NORTHEAST WISCONSIN...BUT A SECOND 50 KNOT 850/700 MB JET MAX LIFTS OUT OF ILLINOIS LATE TONIGHT REACHING LOWER MICHIGAN AROUND SUNRISE. 700 MB UPWARD MOTION INCREASES AROUND MIDNIGHT BEFORE MOVING OFF TO THE EAST BY SUNRISE. ZERO TO 1 KM CAPE OF AROUND 600 JOULES/KG OVER SOUTH CENTRAL WISCONSIN MOVES INTO THE SOUTHEAST DURING THE EARLY MORNING HOURS AND WEAKENS A BIT. 00Z NAM AND LATEST HRRR ALSO INCREASE THE PRECIPITATION. THEREFORE SHOWERS/THUNDERSTORMS STILL LIKELY. RAP SOUNDINGS SATURATE SO CAPE LESSENS. STILL CANT RULE OUT A THUNDERSTORM BRIEFLY REACHING SEVERE CRITERIA. && .AVIATION/06Z TAFS/... VFR CONDITIONS EXPECTED THIS EVENING. SOME IFR VSBYS POSSIBLE NEAR LAKE MICHIGAN...MAINLY NORTH OF MILWAUKEE. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE INTO THE MIDNIGHT HOUR. THEN EXPECT THE SHOWERS AND SCATTERED THUNDERSTORMS TO INCREASE IN COVERAGE. MVFR VISIBILITIES AND SOME MVFR CIGS ARE EXPECTED...WITH GUSTY WINDS AND SMALL HAIL POSSIBLE IN THE STRONGEST STORMS. COLD FRONT MOVES EAST THROUGH THE AREA BETWEEN FRIDAY MORNING. SOUTHWEST WINDS WILL SHIFT TO THE WEST SOUTHWEST...WITH GUSTS TO 20 KNOTS BY FRIDAY AFTERNOON. VFR CONDITIONS EXPECTED. && .PREV DISCUSSION... /ISSUED 335 PM CDT THU MAY 8 2014/ TONIGHT AND FRIDAY...FORECAST CONFIDENCE - MEDIUM. STREAM OF MIDDLE TO HIGH CLOUDS CONTINUES TO FEED INTO PORTIONS OF SOUTHERN WISCONSIN FROM THE SOUTHWEST. THERE ARE SOME BREAKS DEVELOPING ACROSS PORTIONS OF FAR SOUTH CENTRAL AND SOUTHEAST WISCONSIN. NOT SURE IF THE REST OF THE AREA WILL SEE THESE CLOUDS MOVE OUT...WHICH WILL LIMIT THE HIGHS AND SUBSEQUENT CAPE VALUES. WARM AIR ADVECTION IN THE 850 MB TO 700 MB LAYER CONTINUES TO GENERATE SEVERAL AREAS OF LIGHT SHOWERS ACROSS THE AREA. THESE SHOULD LINGER AS THEY SHIFT NORTHEASTWARD WITHIN THE WARM AIR ADVECTION REGIME. MAIN ISSUE WILL BE TIMING OF CONVECTION INTO TONIGHT...AND SEVERE STORM CHANCES. MESOSCALE MODELS ARE SHOWING A GENERAL TREND TOWARD CLUSTERS OF SHOWERS AND STORMS MOVING EAST NORTHEAST THROUGH THE AREA MAINLY THIS EVENING...LINGERING INTO THE OVERNIGHT HOURS. HOWEVER...THE CONVECTION CONTINUES TO NOT LOOK VERY ROBUST...AND EVEN APPEARS TO WEAKEN AS IT MOVES THROUGH THE AREA THIS EVENING. THE COLD FRONT DOES NOT MOVE THROUGH UNTIL LATER TONIGHT INTO FRIDAY MORNING. MAIN 500 MB SHORTWAVE TROUGH REMAINS NORTHWEST OF THE AREA...BUT SEVERAL EMBEDDED VORTICITY MAXIMA SHIFT NORTHEAST THROUGH THE AREA. 850 MB LOW LEVEL JET ALSO INCREASES TONIGHT ACROSS THE AREA. THUS...STILL EXPECTING ROUND OF SHOWERS AND STORMS THIS EVENING INTO THE OVERNIGHT HOURS. 20Z SPC DAY 1 OUTLOOK STILL HAS A SLIGHT RISK FOR SEVERE STORMS ACROSS THE AREA. THE BEST SHOT WILL BE IN THE WESTERN COUNTIES THIS EVENING...AS STORMS MOVE INTO THE AREA FROM THE WEST. STORMS MAY WEAKEN BY THE TIME THEY MAKE IT INTO THE EASTERN PORTIONS OF THE AREA. STILL...ENOUGH MEAN LAYER CAPE AND DEEP LAYER SHEAR TO SUPPORT SOME SEVERE STORMS IN THE WESTERN COUNTIES. CIPS ANALOGS AND CWASP VALUES STILL SUPPORTIVE AS WELL. FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE - MEDIUM. WEAK SHORT WAVE RIDGING SHOULD RESULT IN A QUIET NIGHT FRIDAY NIGHT UNDER CLEAR TO PARTLY CLOUDY SKIES. ON SATURDAY...SHORT TERM MODEL CONCENSUS ON SHORT WAVE LOW PRESSURE TROUGH TO MOVE EWD ACROSS THE NORTHERN PLAINS TOWARD WI. HOWEVER DIFFERENCES EXIST IN STRENGTH AND TIMING OF THIS FEATURE. 12Z NAM MUCH MORE AGGRESSIVE WITH MOISTURE RETURN AND STRONGER FORCING WHILE GFS AND ECMWF IN REASONABLE AGREEMENT FOR SLOWER...WEAKER SOLUTION. NAM HAS DEVELOPING LOW LEVEL JET PIVOTING INTO SRN WI BY 00Z/SUNDAY WHILE ALL OTHER SHORT TERM GUIDANCE MUCH WEAKER AND FARTHER WEST WITH LLJ AXIS. HENCE LEANING MORE TOWARD GFS SOLUTION FOR SATURDAY AFTN WITH LESS CHANCE FOR -SHRA AND LIGHT WINDS TURNING ONSHORE RESULTING IN COOLER AFTN LAKESHORE TEMPS. SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE - MEDIUM. WEAKENING LOW LEVEL JET DOES EVENTUALLY PIVOT EWD ACROSS WI SAT NIGHT IN ASSOCIATION WITH SHORT WAVE TROUGH MOVING THROUGH THE UPPER MIDWEST TOWARD LAKE SUPERIOR. BEST CHANCE FOR -SHRA FROM THIS FEATURE LOOKS TO BE SAT NIGHT. INCREASING LOW TO MID-LEVEL SOUTH WINDS AHEAD OF SHARPENING UPSTREAM TROUGH WILL BEGIN TO SHIFT BAROCLINIC ZONE AND WARM FRONT BACK TO THE NORTH LATER SUNDAY INTO SUNDAY NIGHT. HENCE KEPT SLIGHTLY HIGHER CHANCE POPS FOR THE AFTN AS THIS FEATURE BEGINS TO SHIFT NWD. SUNDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE - MEDIUM. AN UNSETTLED PERIOD LOOKS TO BE SHAPING UP FOR THE FIRST HALF OF THE EXTENDED PERIOD...THROUGH TUESDAY. INCREASING SOUTH WINDS WILL HELP WARM FRONT PUSH BACK NORTHWARD INTO SOUTHERN WISCONSIN SUN NIGHT AND MONDAY. AMPLIFYING UPSTREAM LONG WAVE TROUGH SPREADING INTO THE CENTRAL CONUS SUNDAY AND MONDAY WILL BE RESPONSIBLE FOR THE SHIFTING WARM FRONT AND INCREASING SOUTH WINDS. AS LONG WAVE TROUGH WEAKENS ON MONDAY...PIECE OF MID-LEVEL ENERGY MOVES NORTHEAST THROUGH THE UPPER MIDWEST AROUND MON NIGHT. LOW PRESSURE ASSOCIATED WITH UPPER LEVEL SHORT WAVE MOVES ACROSS WISCONSIN DURING THIS TIME....DRAGGING COLD FRONT THROUGH MONDAY NIGHT. IFFY ON SEVERE WEATHER RISK...WITH BEST CHANCE IN THE WEST MON EVE. ALL EXTENDED GUIDANCE HANGS ON TO UPPER LEVEL TROF LINGERING OVER UPPER MIDWEST THROUGH MIDDLE OF NEXT WEEK...WHICH WILL KEEP THE CHANCE FOR LIGHTER SHOWERY PRECIPITATION CONTINUING THROUGH MID- WEEK. DAYTIME TEMPERATURES FOR THIS PERIOD LOOK TO FALL TO BELOW SEASONAL NORMAL EARLY NEXT WEEK. AVIATION/00Z TAFS/...VFR CONDITIONS EXPECTED INTO THE EARLY EVENING HOURS AT TAF SITES. ON AND OFF GUSTY SOUTH SOUTHWEST WINDS SHOULD LINGER INTO THE EARLY EVENING. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE INTO EARLY EVENING. BEST SHOT FOR STORMS WILL BE IN THE 02Z TO 08Z FRIDAY PERIOD AT MADISON...AND 03Z TO 11Z FRIDAY PERIOD AT THE EASTERN SITES. MVFR VISIBILITIES ARE EXPECTED...WITH GUSTY WINDS AND HAIL POSSIBLE IN THE STRONGEST STORMS. COLD FRONT MOVES EAST THROUGH THE AREA BETWEEN 09Z AND 16Z FRIDAY. SOUTHWEST WINDS WILL SHIFT TO THE WEST SOUTHWEST...WITH GUSTS TO 20 KNOTS BY FRIDAY AFTERNOON. SKIES SHOULD BECOME PARTLY TO MOSTLY SUNNY BY AFTERNOON AS WELL. MARINE...WEST SOUTHWEST WINDS MAY GUST TO 22 KNOTS AT TIMES FRIDAY...BEHIND THE DEPARTING COLD FRONT. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR FRIDAY. AREAS OF FOG SHOULD LINGER INTO EARLY THIS EVENING NORTH OF PORT WASHINGTON...UNTIL WARM FRONT MOVES NORTH OF THE AREA. DENSE FOG IS POSSIBLE...BUT NOT CONFIDENT ENOUGH TO ISSUE A DENSE FOG ADVISORY. INCREASING SOUTH SOUTHWEST WINDS SHOULD ALLOW THE FOG TO MIX OUT BY TONIGHT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...HENTZ TONIGHT/FRIDAY AND AVIATION/MARINE...WOOD FRIDAY NIGHT THROUGH THURSDAY...MBK
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
728 PM CDT THU MAY 8 2014 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 711 PM CDT THU MAY 8 2014 CERTAINLY NOT GIVING UP ON THE SEVERE POTENTIAL...BUT CURRENT INDICATIONS SUGGEST THAT A WIDESPREAD EVENT IS NOT LIKELY. MSAS SFC ANALYSIS SHOWED THAT THE WARM FRONT WAS SITUATED FROM WEST CENTRAL WI TO AROUND WISCONSIN RAPIDS...OSHKOSH AND SHEBOYGAN. WIDESPREAD SHOWERS AND TSTMS WERE OCCURRING OVER THE NW HALF OF WI...AND WERE COMPETING FOR THE MARGINAL INSTABILITY (MUCAPE 400-800 J/KG) THAT WAS SITUATED ACROSS THE AREA. TSTMS WERE ALSO BATTLING SOME LINGERING SURFACE-BASED CONVECTIVE INHIBITION. SHEAR IS QUITE STRONG...WITH 0-6 KM BULK SHEAR OF 40-50 KTS...AND 0-3 KM SRH OF 200-400...SO WILL NEED TO MONITOR ANY CELLS THAT BECOME ISOLATED FROM THE ONGOING CLUSTERS. HAVE SEEN SOME INTERESTING STORM MORPHOLOGY... INCLUDING A RECENT CELL SPLIT OVER WC WI...AND RESULTING RIGHT- MOVING SUPERCELL CURRENTLY MOVG THROUGH NW JACKSON COUNTY. DESPITE A LARGE NUMBERS OF ONGOING STORMS OVER MN/IA AND WSTRN WI...THERE ARE RELATIVELY FEW WARNINGS CURRENTLY IN EFFECT. CURRENT INDICATIONS SUGGEST THAT A WIDESPREAD SVR EVENT IS NOT LIKELY...BUT LOCAL SUPERCELLS OR SHORT LINE SEGMENTS MAY POSE AN ISOLD SVR THREAT...LARGE HAIL AND DAMAGING WINDS...THROUGH THE NIGHT. && .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 330 PM CDT THU MAY 8 2014 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE CENTERED OVER EASTERN NEBRASKA AND A WARM FRONT SNAKING ITS WAY FROM JUST SOUTH OF MINNEAPOLIS TO VOLK FIELD TO WEST BEND WISCONSIN. OCCASIONAL LIGHT SHOWERS CONTINUE TO REDEVELOP OVER THE WARM FRONT...WHICH HAVE BEEN MAINLY IMPACTING CENTRAL TO NORTHEAST WISCONSIN. BUT WITH THE FORWARD MOTION OF FRONT AT A SNAILS PACE...INSTABILITY HAS BEEN SLOW TO DEVELOP THIS AFTERNOON. ADDITIONAL LIGHT SHOWERS ASSOCIATED WITH A WEAK SHORTWAVE ARE ALSO MOVING NORTHEAST OVER SOUTHERN WISCONSIN AND WILL MOVE INTO THE FOX VALLEY OVER THE NEXT HOUR OR TWO. THIS WAVE WAS PRODUCING THUNDERSTORMS OVER IOWA EARLIER BUT THOSE HAVE SINCE WEAKENED. THE MAIN SHOW HOWEVER...IS OCCURRING OVER MINNESOTA AND NORTHERN IOWA WHERE STRONG TO SEVERE THUNDERSTORMS ARE OCCURRING ALONG AN UPPER LEVEL FRONT. AS THIS FRONT MOVES EAST...CHANCES OF SEVERE WEATHER ARE THE MAIN FORECAST CONCERN. TONIGHT...LOW PRESSURE WILL BE TRAVELING FROM SOUTHWEST MINNESOTA TO THE WESTERN TIP OF LAKE SUPERIOR. POTENTIAL WILL REMAIN FOR THE WARM FRONT TO BOW NORTHWARD ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN THIS EVENING DUE STRENGTHENING SOUTHERLY FLOW AHEAD OF THE LOW. HOW FAR NORTH IS STILL QUESTIONABLE GIVEN THE SCATTERED SHOWER ACTIVITY...CLOUD COVER...AND EASTERLY FLOW. SHORTWAVE OVER EASTERN IOWA WILL BE LIFTING NE ACROSS THE FORECAST AREA LATE THIS AFTERNOON INTO THE EVENING AT PEAK HEATING. THINKING SCT SHOWERS AND ISOLD TSTORMS WILL CONTINUE TO BE GENERATED FROM THIS WAVE...THAT COULD HELP TO KEEP THE WARM FRONT FARTHER SOUTH THAN MODELS DEPICT. IF ANY STORMS DEVELOP...40-50KTS OF BULK SHEAR WILL SUPPORT A CHANCE OF LARGE HAIL AND DAMAGING WINDS...TO A LESSER EXTENT.. THEN ATTENTION WILL TURN TO SEVERE THUNDERSTORMS WHICH ARE EXPECTED TO DEVELOP LATER THIS AFTERNOON OVER MINNESOTA AND IOWA. THE LATEST SHORT RANGE GUIDANCE SHOWS THIS CONVECTION...IN THE FORM OF LINE SEGMENTS...MOVING INTO CENTRAL AND NORTH-CENTRAL WISCONSIN BY MID-EVENING. CONVERGENCE ALONG THE UPPER LEVEL TROUGH AND UPPER CONVERGENCE WILL PROVIDE DECENT FORCING FOR STORMS TO SUSTAIN THEMSELVES. RATHER DIFFICULT TO GET GAUGE ON INSTABILITY SINCE PROGGED SOUNDINGS ARE EITHER CONTAMINATED WITH CONVECTION OR NOT REPRESENTATIVE OF THE CURRENT ENVIRONMENT. BUT ELEVATED CAPES ARE GENERALLY AROUND 1K J/KG AND THATS A DECENT PLACE TO START. STEEP MID-LEVEL LAPSE RATES AROUND 7 C/KM AND BULK SHEARS IN THE 35-40 KT RANGE WILL SUPPORT A LARGE HAIL AND DAMAGING WIND THREAT. CHANCES OF SEVERE THUNDERSTORMS LOOK BETTER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN AS INSTABILITY DIMINISHES TO THE EAST. THE STORMS SHOULD EXIT LATE OVERNIGHT...BUT ADDITIONAL SPOTTY SHOWERS AND STORMS COULD STILL POP UP ALONG THE TRAILING SURFACE COLD FRONT. TEMPS WILL BE WARM TONIGHT AND RANGE MAINLY FROM THE MID 50S TO LOW 60S. FRIDAY...THE SURFACE COLD FRONT WILL EXIT EASTERN WISCONSIN BY MID-MORNING...AND COULD SEE A PERIOD OF CLEARING OCCUR RIGHT BEHIND THE FRONT AND BENEATH THE DRY SLOT. THEN SHOULD SEE WRAP AROUND MOISTURE PUSH EAST ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN THROUGH THE REST OF THE DAY. PROGGED SOUNDINGS SHOW A STRONG INVERSION AT ABOUT 750MB...SO TONED BACK THE CHANCE OF SHOWERS OVER CENTRAL AND NORTH-CENTRAL WISCONSIN SOME. AIR BEHIND THE FRONT IS NOT ALL THAT COLD...AND KEPT TEMPERATURES RANGING FROM THE LOW 60S WEST TO NEAR 70 NORTHEAST. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 330 PM CDT THU MAY 8 2014 LARGE SCALE MEAN FLOW IS EXPECTED TO BRIEFLY DEAMPLIFY THIS WEEKEND BEFORE RE-AMPLIFYING EARLY NEXT WEEK AS UPR RIDGING OCCURS OVER THE WEST COAST AND AN EWD MOVING LONGWAVE TROF SHIFTS FROM THE CNTRL CONUS TO E-CNTRL NORTH AMERICA. PCPN CHCS TO BE ASSOCIATED FIRST WITH A WEAK IMPULSE EJECTED NE FROM THE MEAN UPR TROF DURING THE LATTER PART OF THE WEEKEND AND THEN EARLY NEXT WEEK WITIH THE APPROACH OF THE UPR TROF AND THE MAIN SFC CYCLONE/ CDFNT. TEMPS ARE FCST TO GO FROM SLIGHTLY ABOVE NORMAL EARLY...TO BELOW NORMAL BY MID-WEEK AS THE MEAN FLOW TURNS NW. ANY LINGERING LIGHT SHWRS OVER NRN WI SHOULD GRADUALLY COME TO AN END FRI EVENING AS THE SHORTWAVE TROF CONTS TO TRACK NE INTO SRN ONTARIO. OTHERWISE...THE MDLS INDICATE A WEAK SFC RDG/RISING UPR HEIGHTS WORKING EAST TOWARD THE WRN GREAT LAKES DURING THE OVRNGT HOURS. DECREASING CLOUDS WITH DIMINISHING WINDS COULD SEND TEMPS DOWN INTO THE 35-40 DEG RANGE NORTH...LWR TO MID 40S SOUTH. SFC RDG MOVES ACROSS NE WI SAT MORNING AND BE TO OUR EAST BY SAT AFTERNOON. MEANWHILE TO OUR WEST...A PIECE OF SHORTWAVE ENERGY IS PROGGED TO EJECT EWD FROM THE DEVELOPING WRN CONUS UPR TROF AND ALREADY BY PUSHING INTO THE UPR MS VALLEY BY 00Z SUNDAY. CLOUDS SHOULD ALREADY BEGIN TO INCREASE INTO CNTRL WI SAT AFTERNOON... BUT WL KEEP PCPN OUT OF THE FCST FOR NOW. MAX TEMPS TO REMAIN A LITTLE ABOVE NORMAL AS WINDS ATTEMPT TO BACK TO THE SOUTH ONCE AGAIN AHEAD OF THE APPROACHING SHORTWAVE TROF. THIS SHORTWAVE TROF TO THEN RACE ACROSS WI SAT NGT...THEREBY BRINGING A CHC OF SHWRS TO THE ENTIRE FCST AREA. INSTABILITY LOOKS MARGINAL RIGHT NOW AND MAY GENERATE AN ISOLATED TSTM OR TWO ACROSS CNTRL/E-CNTRL WI. PLENTY OF CLOUDS/PCPN IN THE VCNTY WL HOLD MIN TEMPS IN THE MID TO UPR 40S NORTH...UPR 40S TO LWR 50 SOUTH. THERE MAY NOW BE A BRIEF BREAK IN THE PCPN CHCS SUNDAY MORNING AS ONCE SHORTWAVE TROF DEPARTS AND THE NEXT SHORTWAVE TROF APPROACHES SUNDAY AFTERNOON. MAY TRY TO SHOW THIS IN THE GRIDS BETTER AND FOCUS THE CHC POPS MORE IN THE AFTERNOON PERIOD. ONE MORE DAY WITH ABOVE NORMAL TEMPS AS READINGS REACH THE MID TO UPR 60S (COOLER NEAR LAKE MI). BY THE START OF THE WORK WEEK...THE LONGWAVE TROF IS WELL- ESTABLISHED OVER THE ROCKIES WITH A DOWNSTREAM UPR RDG OVER E-CNTRL NORTH AMERICA. PREVAILING SW WINDS WL BRING GULF MOISTURE INTO WI ON MON AND LIFT BOTH A SFC LOW AND WRMFNT NORTH INTO WI MON AFTERNOON. FOLLOWED CLOSER TO THE ECMWF MDL HERE AS THE GFS APPEARS TO EJECT THE MAIN UPR TROF TOO QUICKLY INTO THE PLAINS. ANOTHER ROUND OF SHWRS/ISOLATED TSTMS FOR NE WI ON MON WITH MAX TEMPS CLOSER TO NORMAL. A STRONG UPR JET MAX ROUNDS THE BASE OF THE LONGWAVE TROF BY MON EVENING AND RACES NEWD THRU THE MIDWEST TO THE UPR MS VALLEY/WRN GREAT LAKES MON NGT. SHWRS/ISOLATED TSTMS TO CONT MON NGT AS THE CDFNT PUSHES INTO THE REGION. BY TUE...THE UPR TROF DOES MOVE INTO THE PLAINS...BUT THE WRN GREAT LAKES TO BE UNDER THE INFLUENCE OF A DRY SLOT...THUS TUE COULD END UP DRY. MAX TEMPS ON TUE TO AGAIN BE CLOSE TO NORMAL. PCPN CHCS TO THEN INCREASE ONCE AGAIN MID-WEEK AS THE UPR TROF SHIFTS EAST AND SETTLES OVER THE GREAT LAKES. A SERIES OF SHORTWAVES MOVING THRU THE NOW NW FLOW ALOFT WL BRING UNSETTLED WEATHER TO NE WI ON WED AND THU. TEMPS WL DROP TO BELOW NORMAL LEVELS AND WL HAVE TO WATCH N-CNTRL WI WED NGT FOR THE POTENTIAL OF A RAIN/SNOW MIX AS TEMPS FALL INTO THE MID 30S. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 625 PM CDT THU MAY 8 2014 A WARM FRONT WILL LIFT NORTH ACROSS WISCONSIN TONIGHT...FOLLOWED BY A COLD FRONTAL PASSAGE FRIDAY MORNING. PERIODS OF SHOWERS AND TSTMS WILL DEVELOP IN ASSOCIATION WITH THESE FRONTAL BOUNDARIES. THE THREAT OF WIDESPREAD SVR TSTMS SEEMS LIMITED DUE TO A LACK OF STRONG INSTABILITY...BUT ISOLD SVR TSTMS WILL BE POSSIBLE. MVFR CONDITIONS ARE EXPECTED WITH THE TSTM ACTIVITY. THE SHRA/TSRA SHOULD EXIT THE REGION LATE TONIGHT OR EARLY FRIDAY MORNING. MVFR CIGS WILL LIKELY AFFECT MUCH OF NC/C WI ON FRIDAY...ALONG WITH SCT SHOWERS DURING THE AFTERNOON. LLWS IS EXPECTED THIS EVENING INTO THE EARLY OVERNIGHT HOURS... ESPECIALLY C/NE/EC WI. GUSTY SW-W WINDS WILL DEVELOP BEHIND THE FRONT BY MID TO LATE FRIDAY MORNING. && .MARINE... ISSUED AT 330 PM CDT THU MAY 8 2014 FOG HAS BEEN SLOW TO FORM SO FAR TODAY DESPITE WARMER AND MORE MOIST AIR INVADING THE REGION. WILL JUST KEEP A PATCHY MENTION IN THE FORECAST UNTIL A MORE CERTAIN TREND IS OBSERVED. && .HYDROLOGY... ISSUED AT 330 PM CDT THU MAY 8 2014 THE ABUNDANT MOISTURE FLOWING NWD INTO THE AREA IS STARTING TO LEAD TO AN INCREASED RISK OF HEAVY RAINS/FLOODING. AT LEAST WE NOW HAVE THE CREST OF THE SNOWMELT WATER THROUGH THE RIVERS...SO CAPACITY FOR RUNOFF FROM RAINS IS GREATER THAN A COUPLE WEEKS AGO. IT/S HARD TO PINPOINT A SPECIFIC RGN OF THE FCST AREA WITH THE GREATEST RISK OF FLOODING...BUT MOST LIKELY COULD OCCUR OVER EAST- CENTRAL WISCONSIN LATER TONIGHT AS STORMS BECOME PARALLEL TO THE MEAN FLOW. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........KIECKBUSCH SHORT TERM.....MPC LONG TERM......KALLAS AVIATION.......KIECKBUSCH MARINE.........MPC HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
635 PM CDT THU MAY 8 2014 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 330 PM CDT THU MAY 8 2014 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE CENTERED OVER EASTERN NEBRASKA AND A WARM FRONT SNAKING ITS WAY FROM JUST SOUTH OF MINNEAPOLIS TO VOLK FIELD TO WEST BEND WISCONSIN. OCCASIONAL LIGHT SHOWERS CONTINUE TO REDEVELOP OVER THE WARM FRONT...WHICH HAVE BEEN MAINLY IMPACTING CENTRAL TO NORTHEAST WISCONSIN. BUT WITH THE FORWARD MOTION OF FRONT AT A SNAILS PACE...INSTABILITY HAS BEEN SLOW TO DEVELOP THIS AFTERNOON. ADDITIONAL LIGHT SHOWERS ASSOCIATED WITH A WEAK SHORTWAVE ARE ALSO MOVING NORTHEAST OVER SOUTHERN WISCONSIN AND WILL MOVE INTO THE FOX VALLEY OVER THE NEXT HOUR OR TWO. THIS WAVE WAS PRODUCING THUNDERSTORMS OVER IOWA EARLIER BUT THOSE HAVE SINCE WEAKENED. THE MAIN SHOW HOWEVER...IS OCCURRING OVER MINNESOTA AND NORTHERN IOWA WHERE STRONG TO SEVERE THUNDERSTORMS ARE OCCURRING ALONG AN UPPER LEVEL FRONT. AS THIS FRONT MOVES EAST...CHANCES OF SEVERE WEATHER ARE THE MAIN FORECAST CONCERN. TONIGHT...LOW PRESSURE WILL BE TRAVELING FROM SOUTHWEST MINNESOTA TO THE WESTERN TIP OF LAKE SUPERIOR. POTENTIAL WILL REMAIN FOR THE WARM FRONT TO BOW NORTHWARD ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN THIS EVENING DUE STRENGTHENING SOUTHERLY FLOW AHEAD OF THE LOW. HOW FAR NORTH IS STILL QUESTIONABLE GIVEN THE SCATTERED SHOWER ACTIVITY...CLOUD COVER...AND EASTERLY FLOW. SHORTWAVE OVER EASTERN IOWA WILL BE LIFTING NE ACROSS THE FORECAST AREA LATE THIS AFTERNOON INTO THE EVENING AT PEAK HEATING. THINKING SCT SHOWERS AND ISOLD TSTORMS WILL CONTINUE TO BE GENERATED FROM THIS WAVE...THAT COULD HELP TO KEEP THE WARM FRONT FARTHER SOUTH THAN MODELS DEPICT. IF ANY STORMS DEVELOP...40-50KTS OF BULK SHEAR WILL SUPPORT A CHANCE OF LARGE HAIL AND DAMAGING WINDS...TO A LESSER EXTENT.. THEN ATTENTION WILL TURN TO SEVERE THUNDERSTORMS WHICH ARE EXPECTED TO DEVELOP LATER THIS AFTERNOON OVER MINNESOTA AND IOWA. THE LATEST SHORT RANGE GUIDANCE SHOWS THIS CONVECTION...IN THE FORM OF LINE SEGMENTS...MOVING INTO CENTRAL AND NORTH-CENTRAL WISCONSIN BY MID-EVENING. CONVERGENCE ALONG THE UPPER LEVEL TROUGH AND UPPER CONVERGENCE WILL PROVIDE DECENT FORCING FOR STORMS TO SUSTAIN THEMSELVES. RATHER DIFFICULT TO GET GAUGE ON INSTABILITY SINCE PROGGED SOUNDINGS ARE EITHER CONTAMINATED WITH CONVECTION OR NOT REPRESENTATIVE OF THE CURRENT ENVIRONMENT. BUT ELEVATED CAPES ARE GENERALLY AROUND 1K J/KG AND THATS A DECENT PLACE TO START. STEEP MID-LEVEL LAPSE RATES AROUND 7 C/KM AND BULK SHEARS IN THE 35-40 KT RANGE WILL SUPPORT A LARGE HAIL AND DAMAGING WIND THREAT. CHANCES OF SEVERE THUNDERSTORMS LOOK BETTER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN AS INSTABILITY DIMINISHES TO THE EAST. THE STORMS SHOULD EXIT LATE OVERNIGHT...BUT ADDITIONAL SPOTTY SHOWERS AND STORMS COULD STILL POP UP ALONG THE TRAILING SURFACE COLD FRONT. TEMPS WILL BE WARM TONIGHT AND RANGE MAINLY FROM THE MID 50S TO LOW 60S. FRIDAY...THE SURFACE COLD FRONT WILL EXIT EASTERN WISCONSIN BY MID-MORNING...AND COULD SEE A PERIOD OF CLEARING OCCUR RIGHT BEHIND THE FRONT AND BENEATH THE DRY SLOT. THEN SHOULD SEE WRAP AROUND MOISTURE PUSH EAST ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN THROUGH THE REST OF THE DAY. PROGGED SOUNDINGS SHOW A STRONG INVERSION AT ABOUT 750MB...SO TONED BACK THE CHANCE OF SHOWERS OVER CENTRAL AND NORTH-CENTRAL WISCONSIN SOME. AIR BEHIND THE FRONT IS NOT ALL THAT COLD...AND KEPT TEMPERATURES RANGING FROM THE LOW 60S WEST TO NEAR 70 NORTHEAST. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 330 PM CDT THU MAY 8 2014 LARGE SCALE MEAN FLOW IS EXPECTED TO BRIEFLY DEAMPLIFY THIS WEEKEND BEFORE RE-AMPLIFYING EARLY NEXT WEEK AS UPR RIDGING OCCURS OVER THE WEST COAST AND AN EWD MOVING LONGWAVE TROF SHIFTS FROM THE CNTRL CONUS TO E-CNTRL NORTH AMERICA. PCPN CHCS TO BE ASSOCIATED FIRST WITH A WEAK IMPULSE EJECTED NE FROM THE MEAN UPR TROF DURING THE LATTER PART OF THE WEEKEND AND THEN EARLY NEXT WEEK WITIH THE APPROACH OF THE UPR TROF AND THE MAIN SFC CYCLONE/ CDFNT. TEMPS ARE FCST TO GO FROM SLIGHTLY ABOVE NORMAL EARLY...TO BELOW NORMAL BY MID-WEEK AS THE MEAN FLOW TURNS NW. ANY LINGERING LIGHT SHWRS OVER NRN WI SHOULD GRADUALLY COME TO AN END FRI EVENING AS THE SHORTWAVE TROF CONTS TO TRACK NE INTO SRN ONTARIO. OTHERWISE...THE MDLS INDICATE A WEAK SFC RDG/RISING UPR HEIGHTS WORKING EAST TOWARD THE WRN GREAT LAKES DURING THE OVRNGT HOURS. DECREASING CLOUDS WITH DIMINISHING WINDS COULD SEND TEMPS DOWN INTO THE 35-40 DEG RANGE NORTH...LWR TO MID 40S SOUTH. SFC RDG MOVES ACROSS NE WI SAT MORNING AND BE TO OUR EAST BY SAT AFTERNOON. MEANWHILE TO OUR WEST...A PIECE OF SHORTWAVE ENERGY IS PROGGED TO EJECT EWD FROM THE DEVELOPING WRN CONUS UPR TROF AND ALREADY BY PUSHING INTO THE UPR MS VALLEY BY 00Z SUNDAY. CLOUDS SHOULD ALREADY BEGIN TO INCREASE INTO CNTRL WI SAT AFTERNOON... BUT WL KEEP PCPN OUT OF THE FCST FOR NOW. MAX TEMPS TO REMAIN A LITTLE ABOVE NORMAL AS WINDS ATTEMPT TO BACK TO THE SOUTH ONCE AGAIN AHEAD OF THE APPROACHING SHORTWAVE TROF. THIS SHORTWAVE TROF TO THEN RACE ACROSS WI SAT NGT...THEREBY BRINGING A CHC OF SHWRS TO THE ENTIRE FCST AREA. INSTABILITY LOOKS MARGINAL RIGHT NOW AND MAY GENERATE AN ISOLATED TSTM OR TWO ACROSS CNTRL/E-CNTRL WI. PLENTY OF CLOUDS/PCPN IN THE VCNTY WL HOLD MIN TEMPS IN THE MID TO UPR 40S NORTH...UPR 40S TO LWR 50 SOUTH. THERE MAY NOW BE A BRIEF BREAK IN THE PCPN CHCS SUNDAY MORNING AS ONCE SHORTWAVE TROF DEPARTS AND THE NEXT SHORTWAVE TROF APPROACHES SUNDAY AFTERNOON. MAY TRY TO SHOW THIS IN THE GRIDS BETTER AND FOCUS THE CHC POPS MORE IN THE AFTERNOON PERIOD. ONE MORE DAY WITH ABOVE NORMAL TEMPS AS READINGS REACH THE MID TO UPR 60S (COOLER NEAR LAKE MI). BY THE START OF THE WORK WEEK...THE LONGWAVE TROF IS WELL- ESTABLISHED OVER THE ROCKIES WITH A DOWNSTREAM UPR RDG OVER E-CNTRL NORTH AMERICA. PREVAILING SW WINDS WL BRING GULF MOISTURE INTO WI ON MON AND LIFT BOTH A SFC LOW AND WRMFNT NORTH INTO WI MON AFTERNOON. FOLLOWED CLOSER TO THE ECMWF MDL HERE AS THE GFS APPEARS TO EJECT THE MAIN UPR TROF TOO QUICKLY INTO THE PLAINS. ANOTHER ROUND OF SHWRS/ISOLATED TSTMS FOR NE WI ON MON WITH MAX TEMPS CLOSER TO NORMAL. A STRONG UPR JET MAX ROUNDS THE BASE OF THE LONGWAVE TROF BY MON EVENING AND RACES NEWD THRU THE MIDWEST TO THE UPR MS VALLEY/WRN GREAT LAKES MON NGT. SHWRS/ISOLATED TSTMS TO CONT MON NGT AS THE CDFNT PUSHES INTO THE REGION. BY TUE...THE UPR TROF DOES MOVE INTO THE PLAINS...BUT THE WRN GREAT LAKES TO BE UNDER THE INFLUENCE OF A DRY SLOT...THUS TUE COULD END UP DRY. MAX TEMPS ON TUE TO AGAIN BE CLOSE TO NORMAL. PCPN CHCS TO THEN INCREASE ONCE AGAIN MID-WEEK AS THE UPR TROF SHIFTS EAST AND SETTLES OVER THE GREAT LAKES. A SERIES OF SHORTWAVES MOVING THRU THE NOW NW FLOW ALOFT WL BRING UNSETTLED WEATHER TO NE WI ON WED AND THU. TEMPS WL DROP TO BELOW NORMAL LEVELS AND WL HAVE TO WATCH N-CNTRL WI WED NGT FOR THE POTENTIAL OF A RAIN/SNOW MIX AS TEMPS FALL INTO THE MID 30S. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 625 PM CDT THU MAY 8 2014 A WARM FRONT WILL LIFT NORTH ACROSS WISCONSIN TONIGHT...FOLLOWED BY A COLD FRONTAL PASSAGE FRIDAY MORNING. PERIODS OF SHOWERS AND TSTMS WILL DEVELOP IN ASSOCIATION WITH THESE FRONTAL BOUNDARIES. THE THREAT OF WIDESPREAD SVR TSTMS SEEMS LIMITED DUE TO A LACK OF STRONG INSTABILITY...BUT ISOLD SVR TSTMS WILL BE POSSIBLE. MVFR CONDITIONS ARE EXPECTED WITH THE TSTM ACTIVITY. THE SHRA/TSRA SHOULD EXIT THE REGION LATE TONIGHT OR EARLY FRIDAY MORNING. MVFR CIGS WILL LIKELY AFFECT MUCH OF NC/C WI ON FRIDAY...ALONG WITH SCT SHOWERS DURING THE AFTERNOON. LLWS IS EXPECTED THIS EVENING INTO THE EARLY OVERNIGHT HOURS... ESPECIALLY C/NE/EC WI. GUSTY SW-W WINDS WILL DEVELOP BEHIND THE FRONT BY MID TO LATE FRIDAY MORNING. && .MARINE... ISSUED AT 330 PM CDT THU MAY 8 2014 FOG HAS BEEN SLOW TO FORM SO FAR TODAY DESPITE WARMER AND MORE MOIST AIR INVADING THE REGION. WILL JUST KEEP A PATCHY MENTION IN THE FORECAST UNTIL A MORE CERTAIN TREND IS OBSERVED. && .HYDROLOGY... ISSUED AT 330 PM CDT THU MAY 8 2014 THE ABUNDANT MOISTURE FLOWING NWD INTO THE AREA IS STARTING TO LEAD TO AN INCREASED RISK OF HEAVY RAINS/FLOODING. AT LEAST WE NOW HAVE THE CREST OF THE SNOWMELT WATER THROUGH THE RIVERS...SO CAPACITY FOR RUNOFF FROM RAINS IS GREATER THAN A COUPLE WEEKS AGO. IT/S HARD TO PINPOINT A SPECIFIC RGN OF THE FCST AREA WITH THE GREATEST RISK OF FLOODING...BUT MOST LIKELY COULD OCCUR OVER EAST- CENTRAL WISCONSIN LATER TONIGHT AS STORMS BECOME PARALLEL TO THE MEAN FLOW. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......KALLAS AVIATION.......KIECKBUSCH MARINE.........MPC HYDROLOGY......MPC
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 253 PM CDT WED MAY 7 2014 THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE OVER THE KANSAS/NEBRASKA BORDER WITH A WARM FRONT EXTENDING EAST FROM NORTHERN IOWA ACROSS NORTHERN ILLINOIS TO THE CENTRAL APPALACHIANS. NORTH OF THIS WARM FRONT...A SHORTWAVE TURNED MCV IS EXITING THE STATE OVER NORTHERN LAKE MICHIGAN. WAKE LOW WINDS HAVE SUBSIDED BEHIND THIS MCV...BUT SCATTERED CONVECTION CONTINUES TO REDEVELOP FROM WAUSAU TO MANITOWOC IN A REGION OF MID-LEVEL FGEN AND MOISTURE CONVERGENCE ALONG AN 850MB WARM FRONT. THINK THIS CONVECTION WILL LIFT NORTHEAST AND WEAKEN FOR THE REST OF THIS AFTERNOON WHICH SHOULD LEAD TO A PERIOD OF RELATIVELY QUIET CONDITIONS INTO THIS EVENING. LOOKING UPSTREAM...CONVECTION IS DEVELOPING OVER THE EASTERN DAKOTAS AND WESTERN MINNESOTA ALONG AN INVERTED TROUGH. TOUGH TO PICK OUT ANY NOTABLE SHORTWAVES IN THE SOUTHWEST FLOW ALOFT OVER THE PLAINS TO KEY ON FOR PRECIP TONIGHT. WITH BROAD WARM AND MOIST ADVECTION CONTINUE OVER THE NEXT 24 HOURS...THUNDERSTORM AND SEVERE WEATHER CHANCES ARE THE MAIN FORECAST CONCERNS. TONIGHT...AS LOW PRESSURE MOVES INTO THE CENTRAL GREAT PLAINS...AN 850MB WARM FRONT WILL BE LIFTING NORTHWARD ACROSS CENTRAL AND NORTHERN WISCONSIN DURING THE EVENING. THOUGH A PERIOD OF SUBSIDENCE MAY STILL BE ONGOING BEHIND THE MCV THAT IS EXITING NORTHEAST WISCONSIN CURRENTLY...ASCENT OVER THIS WARM FRONT ON THE EDGE OF THE ELEVATED MIXED LAYER SHOULD EVENTUALLY LEAD TO A RE-DEVELOPMENT OF SHOWERS AND THUNDERSTORMS OVER FAR NORTHERN WISCONSIN AND THE UPPER PENINSULA. WITH NO DISCERNIBLE SHORTWAVES UPSTREAM...TIMING OF RE-DEVELOPMENT IS TOUGH TO GET A HANDLE ON...SO KEPT PROBABILITIES IN THE CHANCE RANGE THIS EVENING...AND INCREASED THEM TO LIKELY OVERNIGHT. DUE TO STEEP MID-LEVEL LAPSE RATES IN THE 7-8 C/KM RANGE...ELEVATED CAPES UPWARDS OF 1100 J/KG...AND 0-6 KM BULK SHEARS OF 30-35 KTS...TOUGH TO RULE OUT A MINOR SEVERE THREAT. LARGE HAIL WILL BE THE MAIN THREAT AND DAMAGING WINDS TO A LESSER EXTENT. THURSDAY...LOW PRESSURE WILL LIFT NORTHEAST TOWARDS SOUTH-CENTRAL MINNESOTA. AT THE SAME TIME...A SURFACE WARM FRONT WILL BE SHIFTING NORTHWARD ACROSS THE STATE. HOW QUICKLY THAT WARM FRONT MOVES NORTH IS A BIG QUESTION MARK AS ITS FORWARD PROGRESS WILL LIKELY BE IMPEDED BY MORNING CONVECTION AND CLOUD COVER. IF CLOUDS AND RAINFALL CONTINUE INTO THE AFTERNOON...HAVE A TOUGH TIME SEEING THIS WARM FRONT REACHING THE UPPER PENINSULA BORDER BY 00Z FRI. THE 12Z ECMWF SHOWS THIS WARM FRONT ONLY REACHING THE ROUTE 29 CORRIDOR BY THIS TIME SO THIS SCENARIO IS NOT OUT OF REALM OF POSSIBILITY. WILL SHOW LIKELY POPS OVER N-C WISCONSIN DURING THE MORNING AND A CHANCE EVERYWHERE ELSE AS ISENTROPIC ASCENT CONTINUES. CENTRAL WISCONSIN AND THE FOX VALLEY HAVE THE BEST CHANCE OF CLEARING THE WARM FRONT DURING THE AFTERNOON WHERE TEMPS HAVE POTENTIAL TO REACH INTO THE UPPER 70S TO LOWER 80S. WITH SURFACE DEWPOINTS RISING INTO THE LOWER 60S...ML CAPES WILL RANGE FROM 1500-2000 J/KG OVER CENTRAL WISCONSIN AND THE SOUTHERN FOX VALLEY. 0-6KM BULK SHEAR WILL BE MORE THAN SUFFICIENT FOR THE POSSIBILITY OF DISCRETE CELLS AND WILL HAVE FORCING VIA ISENTROPIC/MOISTURE ADVECTION. LARGE SCALE FORCING WILL STILL BE A CONSIDERABLE DISTANCE TO THE WEST...SO SEVERE WEATHER CHANCES MAY GET DELAYED INTO THE EVENING...BUT CANNOT RULE OUT A FEW SEVERE THUNDERSTORMS TOMORROW AFTERNOON. THE MAIN THREATS WILL BE DAMAGING WINDS AND LARGE HAIL. NO SIGNIFICANT CHANGES TO TEMPS. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 253 PM CDT WED MAY 7 2014 LOW AMPLITUDE/SLIGHTLY AMPLIFIED MEAN FLOW TO GRADUALLY TRANSITION TO A WEST COAST UPR RDG/E-CNTRL NOAM UPR TROF PATTERN NEXT WEEK. THE MAIN FEATURE OF INTEREST WL BE THE PROGRESSIVE EWD MOVEMENT OF A LONGWAVE TROF ACROSS THE CNTRL CONUS EARLY NEXT WEEK. THIS PATTERN SHIFT TO BRING A SW FLOW ALOFT TO NE WI WHICH TRANSLATES TO NEAR NORMAL TEMPS...BUT ALSO A WET PATTERN WITH SEVERAL ROUNDS OF PCPN. SFC LOW CONTS TO SLOWLY TRACK NE ACROSS MN THU NGT WHILE THE CDFNT PUSHES INTO WRN WI DURING THE OVRNGT HOURS. PERSISTENT SW WINDS AHEAD OF THE CDFNT/SHORTWAVE TROF WL CONT TO GET PUMPED INTO WI WITH INDIVIDUAL MID-LEVEL SHORTWAVES LIFTING NE INTO THE GREAT LAKES. ENUF SHEAR IS EVIDENT TO SUPPORT ORGANIZED/ROTATING STORMS...THUS A POTENTIAL OF SEVERE STORMS PERSISTS THU NGT. THE HIGHEST PROBABILITY OF SEVERE LOOKS TO BE TO OUR WEST NEAR THE TRACK OF THE SFC LOW...HOWEVER LARGE HAIL AND/OR DAMAGING WINDS ARE POSSIBLE ACROSS THE ENTIRE FCST AREA. MIN TEMPS TO ACTUALLY HAVE SUMMER FEEL TO THEM WITH DEW POINTS HOLDING IN THE 50S THRU THE NGT. LOOK FOR READINGS TO ONLY DROP INTO THE LWR TO MID 50S AROUND DOOR COUNTY TO THE LWR 60S ACROSS E-CNTRL WI. THE CDFNT DRIVES THRU CNTRL WI FRI MORNING/ERN WI EARLY TO MID FRI AFTERNOON AND WL NEED TO CARRY POPS UNTIL THIS FNT CLEARS THE AREA. EVEN BEHIND THE FNT...CANNOT RULE OUT ADDITIONAL SHWR ACTIVITY AS THE SHORTWAVE TROF/EMBEDDED SHORTWAVE MOVE THRU WI. HAVE CONTINUED THE LOW-END POPS ACROSS THE ENTIRE FCST AREA THRU THE AFTERNOON HOURS. WARMEST TEMPS ON FRI TO BE OVER ERN WI PRIOR TO THE COLD FRONTAL PASSAGE WITH READINGS IN THE UPR 60S. WEAKENING SHORTWAVE TROF IS FCST TO LIFT NE INTO ONTARIO FRI NGT... BUT MAY STILL BE CLOSE ENUF TO NE WI TO WARRANT A SMALL POP OVER NRN SECTIONS OF THE FCST AREA FRI EVENING. OTHERWISE...A WEAK RDG OF HI PRES WL BUILD TOWARD THE WRN GREAT LAKES LATER FRI NGT AND BRING CLEARING SKIES AND COOLER CONDITIONS TO THE REGION. MIN TEMPS TO RANGE FROM THE UPR 30S TO LWR 40S NORTH TO THE LWR TO MID 40S SOUTH. THIS SFC RDG QUICKLY MOVES ACROSS WI ON SAT WITH CLOUDS ALREADY BEGINNING TO INCREASE AHEAD OF A SHORTWAVE TROF PUSHING TOWARD THE UPR MS VALLEY. HAVE KEPT ANY PCPN OUT OF THE FCST AREA FOR NOW AND KEPT MAX TEMPS MAINLY IN THE 65-70 DEG RANGE (COOLER NEAR LAKE MI). UNSETTLED WEATHER EXPECTED FOR THE FIRST HALF OF NEXT WEEK AS AN UPR TROF SLOWLY WORKS ACROSS THE CNTRL CONUS. SW FLOW ALOFT WL BRING GULF MOISTURE INTO THE WRN GREAT LAKES WITH CHC POPS NECESSARY FROM SAT NGT THRU MON NGT. THE PASSAGE OF A CDFNT MON NGT FOLLOWED BY A DRY SLOT ON TUE COULD BRING A BREAK IN THE PCPN BEFORE THE UPR TROF ARRIVES AND BRINGS CHC POPS BACK INTO THE FCST. TEMPS WL COOL A BIT EARLY NEXT WEEK WITH READINGS SLIGHTLY BELOW NORMAL. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1150 AM CDT WED MAY 7 2014 A STRONG WARM FRONT WILL BE LIFTING NORTHWARD ACROSS THE WESTERN GREAT LAKES AND INTO CENTRAL WISCONSIN BY THE END OF THE TAF PERIOD. NORTH OF THE WARM FRONT...PERIODS OF SHOWERS AND THUNDERSTORMS ARE LIKELY...BUT TIMING THESE PERIODS REMAINS VERY DIFFICULT. THE ROUND MOVING ACROSS NORTHEAST WISCONSIN CURRENTLY WILL EXIT OVER THE NEXT HOUR OR TWO...THEN COULD SEE A SEVERAL HOUR BREAK INTO EARLY THIS EVENING. TOUGH TO RULE OUT A POP UP STORM...BUT COVERAGE IS EXPECTED TO BE ISOLATED UNTIL THE EVENING. THEN THE FOCUS WILL LOOK TOWARD FAR NORTHERN WISCONSIN TONIGHT...BUT STORMS COULD TURN SOUTHEAST INTO CENTRAL PARTS OF THE STATE TOO. REDEVELOPMENT OF THUNDERSTORMS IS POSSIBLE BY MID TO LATE EVENING. ANOTHER ROUND OF STORMS COULD ALSO ARRIVE TOMORROW MORNING. WITH THE APPROACHING WARM FRONT...EXPECT CIGS AND VSBYS TO FALL TONIGHT INTO THURSDAY MORNING. && .MARINE... ISSUED AT 253 PM CDT WED MAY 7 2014 FOG IS POSSIBLE LATE TONIGHT INTO TOMORROW AS WARM AND HUMID AIR INVADES FROM THE SOUTH. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......KALLAS AVIATION.......MPC MARINE.........MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1245 PM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM CDT WED MAY 7 2014 AT 3 AM...WATCHING 2 AREAS OF CONVECTION. THE FIRST IS LOCATED OVER EAST CENTRAL WISCONSIN. MEANWHILE THE OTHER ONE IS LOCATED BETWEEN SIOUX FALLS SOUTH DAKOTA AND FAIRMONT MINNESOTA. BOTH OF THESE ARE LOCATED ON THE EASTERN EDGE STRONG 700 MB MOISTURE CONVERGENT AREA. IN ADDITION...THEY ARE LOCATED ONE THE NORTHERN PERIPHERY OF 1000 J/KG MOST UNSTABLE CAPE. THE ARW...NMM...HOP WRF AND SPC WRF SUGGEST THAT THE LATTER AREA OF CONVECTION WILL MOVE EAST ALONG THE INTERSTATE 90 CORRIDOR THIS MORNING. EARLIER IN THE NIGHT THE HRRR SUGGESTED A SIMILAR SCENARIO...BUT WITH ITS LATEST RUN IT HAS BACKED AWAY FROM THIS SOLUTION. HOWEVER THIS SCENARIO DOES NOT MAKE A LOT OF SENSE...SO BACKED AWAY FROM FOLLOWING IT. TRENDED THE PRECIPITATION FORECAST FOR TODAY TOWARD A BLEND OF ARW...NMM...HOP WRF AND SPC WRF. HOWEVER I AM A BIT CONCERNED THAT AS IT MOVES EAST THAT THE NOCTURNAL JET WILL WEAKEN AND THAT THE CONVECTION COULD DISSIPATE BEFORE IT GETS INTO OUR AREA. IF THE CONVECTION DOES HAPPEN TO GET INTO OUR AREA...THE SPC RAP SUGGESTS THAT EFFECTIVE SHEAR WILL INCREASE OVER 40 KNOTS THROUGH 07.14Z. THIS COULD RESULT IN THE DEVELOPMEMT OF SOME ELEVATED SUPER CELLS. WE WILL HAVE TO MONITOR THIS OVER THE NEXT COUPLE OF HOURS. FOR LATER THIS MORNING AND AFTERNOON...MANY OF THE MESO MODELS AND AND NAM SUGGEST THAT THE AREA WILL REMAIN DRY. THIS IS A RESULT OF AN ELEVATED MIXED LAYER BEING BROUGHT ISENTROPICALLY OFF OF THE SOUTHERN PLAINS. THIS LAYER FORMS A STRONG 800 TO 600 MB CAP ACROSS THE FORECAST AREA. MEANWHILE THE GFS CONTINUES TO TRY AND DEVELOP STRATIFORM PRECIPITATION BELOW THE CAP. THIS LOOKS VERY UNLIKELY BECAUSE ITS SATURATED THE AIR MASS BELOW 800 MB TOO MUCH. DUE TO THIS...STAYED WITH A DRY FORECAST FOR THE TIME PERIOD. TONIGHT...MANY OF DETERMINISTIC RUNS ARE GENERATING PRECIPITATION ACROSS MUCH OF THE FORECAST AREA. HOWEVER BUFKIT SOUNDINGS CONTINUE TO SHOW A FAIRLY STRONG CAP ALONG AND SOUTH OF INTERSTATE 94. THIS IS GOOD AGREEMENT WITH WHAT SHOWS UP IN THE ARW AND SPC WRF. DUE TO THIS...WENT WITH MUCH LOWER POPS THAN WHAT NORMALLY WOULD BE EXPECTED SOUTH OF INTERSTATE 94. IF THUNDERSTORMS DID DEVELOP...IT LOOKS TO BE SO HIGH /BASES OF 2 TO 3 KM/ THAT YOUR SHEAR IS GREATLY DECREASED TO LESS 25 KNOTS...SO THERE WILL NOT BE SUPERCELLS. HOWEVER THE CAPE PROFILE IS MUCH FATTER THAN THIS MORNING AND THIS COULD POTENTIALLY RESULT IN SOME LARGE HAIL. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 425 AM CDT WED MAY 7 2014 ON THURSDAY AND THURSDAY NIGHT...THE 07.00Z MODELS CONTINUE TO SHOW THAT A PLUME OF SUBTROPICAL MOISTURE WILL SURGE NORTHWARD AHEAD OF THE LONG WAVE TROUGH. EMBEDDED WAVES IN THIS FLOW WILL RESULT IN SHOWERS AND THUNDERSTORMS WHICH WILL USE UP MUCH OF THE CAPE PRIOR TO THE ARRIVAL OF A MUCH MORE FAVORABLE SHEAR PROFILE. DUE TO THIS...STILL THINKING THAT THE BEST SEVERE WEATHER THREAT WILL REMAIN WEST OF INTERSTATE 35. WITH THIS PLUME NOT ARRIVING UNTIL MID MORNING...LOWERED THE PRECIPITATION PROBABILITIES BETWEEN 08.12Z AND 08.15Z. FROM SATURDAY NIGHT THROUGH TUESDAY...A SERIES OF SHORT WAVE TROUGHS WILL EJECTED OUT OF THE LONG WAVE OVER THE WESTERN UNITED STATES. THIS WILL BRING ROUND OF SHOWERS AND THUNDERSTORMS INTO THE AREA. WITH STILL SOME TIMING DIFFERENCES AND SUBTLE DIFFERENCES IN THE MODELS...STAYED WITH THE MODEL CONSENSUS. TOWARD THE MIDDLE OF NEXT WEEK...IT LOOKS LIKE THERE WILL BE A PATTERN SHIFT AS THE UPPER LEVEL FLOW BECOMES NORTHWEST AND WEST ACROSS THE EASTERN UNITED STATES. LOOKS LIKE HIGHS MAY RANGE FROM THE UPPER 40S TO MID 50S...AND LOWS WILL RANGE FROM THE MID 30S TO MID 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1245 PM CDT WED MAY 7 2014 IN THE WAKE OF MORNING STORMS...COOL STABLE EASTERLY FLOW HAS ANCHORED THE WARM FRONT WELL TO THE SOUTH ACROSS CENTRAL IOWA. IN THE PAST COUPLE HOURS...THERE HAS BEEN A SLOW PUSH TO THE NORTH BUT NOT EXPECTING THE FRONT TO MAKE IT TO THE TAF SITES UNTIL THE SURFACE LOW BEGINS TO LIFT MORE TO THE NORTH THIS EVENING. FOR THE OVERNIGHT PERIOD...SOME INDICATIONS THAT STORMS COULD FIRE UP ACROSS SOUTHWEST MINNESOTA INTO CENTRAL MINNESOTA. UNCERTAINTY REMAINS WHETHER KRST WILL BE IMPACTED...BUT FOR NOW INCLUDED A VCTS GROUP. THIS ACTIVITY SHOULD LIFT AWAY FROM THE AREA BY SUNRISE. AFTER 12Z THURSDAY...INCREASING MOISTURE AND LIFT ASSOCIATED WITH THE STRONGER SURFACE LOW AND COLD FRONT TO THE WEST WILL LEAD TO WIDESPREAD SHOWERS AND THUNDERSTORMS...ESPECIALLY CLOSER TO 18Z. THIS IS WHEN THE MOST IMPACTS TO THE TERMINALS COULD BE EXPERIENCED. && .HYDROLOGY... ISSUED AT 425 AM CDT WED MAY 7 2014 FLOODING CONTINUES ALONG THE MAIN STEM OF THE MISSISSIPPI RIVER...WITH LOCATIONS CRESTING FROM NORTH MCGREGOR. SHOWERS AND THUNDERSTORMS ON THURSDAY AND THURSDAY NIGHT WILL PRODUCE ANYWHERE FROM A HALF INCH TO ONE INCH. THIS WILL LIKELY SLOW THE FALL FOR LOCATIONS NORTH OF MCGREGOR...AND MAY INCREASE CRESTS SLIGHTLY SOUTH OF MCGREGOR. CHECK OUT THE LATEST HYDROLOGIC STATEMENTS FOR THE DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM....BOYNE AVIATION.....ZT HYDROLOGY....BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
655 AM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM CDT WED MAY 7 2014 AT 3 AM...WATCHING 2 AREAS OF CONVECTION. THE FIRST IS LOCATED OVER EAST CENTRAL WISCONSIN. MEANWHILE THE OTHER ONE IS LOCATED BETWEEN SIOUX FALLS SOUTH DAKOTA AND FAIRMONT MINNESOTA. BOTH OF THESE ARE LOCATED ON THE EASTERN EDGE STRONG 700 MB MOISTURE CONVERGENT AREA. IN ADDITION...THEY ARE LOCATED ONE THE NORTHERN PERIPHERY OF 1000 J/KG MOST UNSTABLE CAPE. THE ARW...NMM...HOP WRF AND SPC WRF SUGGEST THAT THE LATTER AREA OF CONVECTION WILL MOVE EAST ALONG THE INTERSTATE 90 CORRIDOR THIS MORNING. EARLIER IN THE NIGHT THE HRRR SUGGESTED A SIMILAR SCENARIO...BUT WITH ITS LATEST RUN IT HAS BACKED AWAY FROM THIS SOLUTION. HOWEVER THIS SCENARIO DOES NOT MAKE A LOT OF SENSE...SO BACKED AWAY FROM FOLLOWING IT. TRENDED THE PRECIPITATION FORECAST FOR TODAY TOWARD A BLEND OF ARW...NMM...HOP WRF AND SPC WRF. HOWEVER I AM A BIT CONCERNED THAT AS IT MOVES EAST THAT THE NOCTURNAL JET WILL WEAKEN AND THAT THE CONVECTION COULD DISSIPATE BEFORE IT GETS INTO OUR AREA. IF THE CONVECTION DOES HAPPEN TO GET INTO OUR AREA...THE SPC RAP SUGGESTS THAT EFFECTIVE SHEAR WILL INCREASE OVER 40 KNOTS THROUGH 07.14Z. THIS COULD RESULT IN THE DEVELOPMEMT OF SOME ELEVATED SUPER CELLS. WE WILL HAVE TO MONITOR THIS OVER THE NEXT COUPLE OF HOURS. FOR LATER THIS MORNING AND AFTERNOON...MANY OF THE MESO MODELS AND AND NAM SUGGEST THAT THE AREA WILL REMAIN DRY. THIS IS A RESULT OF AN ELEVATED MIXED LAYER BEING BROUGHT ISENTROPICALLY OFF OF THE SOUTHERN PLAINS. THIS LAYER FORMS A STRONG 800 TO 600 MB CAP ACROSS THE FORECAST AREA. MEANWHILE THE GFS CONTINUES TO TRY AND DEVELOP STRATIFORM PRECIPITATION BELOW THE CAP. THIS LOOKS VERY UNLIKELY BECAUSE ITS SATURATED THE AIR MASS BELOW 800 MB TOO MUCH. DUE TO THIS...STAYED WITH A DRY FORECAST FOR THE TIME PERIOD. TONIGHT...MANY OF DETERMINISTIC RUNS ARE GENERATING PRECIPITATION ACROSS MUCH OF THE FORECAST AREA. HOWEVER BUFKIT SOUNDINGS CONTINUE TO SHOW A FAIRLY STRONG CAP ALONG AND SOUTH OF INTERSTATE 94. THIS IS GOOD AGREEMENT WITH WHAT SHOWS UP IN THE ARW AND SPC WRF. DUE TO THIS...WENT WITH MUCH LOWER POPS THAN WHAT NORMALLY WOULD BE EXPECTED SOUTH OF INTERSTATE 94. IF THUNDERSTORMS DID DEVELOP...IT LOOKS TO BE SO HIGH /BASES OF 2 TO 3 KM/ THAT YOUR SHEAR IS GREATLY DECREASED TO LESS 25 KNOTS...SO THERE WILL NOT BE SUPERCELLS. HOWEVER THE CAPE PROFILE IS MUCH FATTER THAN THIS MORNING AND THIS COULD POTENTIALLY RESULT IN SOME LARGE HAIL. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 425 AM CDT WED MAY 7 2014 ON THURSDAY AND THURSDAY NIGHT...THE 07.00Z MODELS CONTINUE TO SHOW THAT A PLUME OF SUBTROPICAL MOISTURE WILL SURGE NORTHWARD AHEAD OF THE LONG WAVE TROUGH. EMBEDDED WAVES IN THIS FLOW WILL RESULT IN SHOWERS AND THUNDERSTORMS WHICH WILL USE UP MUCH OF THE CAPE PRIOR TO THE ARRIVAL OF A MUCH MORE FAVORABLE SHEAR PROFILE. DUE TO THIS...STILL THINKING THAT THE BEST SEVERE WEATHER THREAT WILL REMAIN WEST OF INTERSTATE 35. WITH THIS PLUME NOT ARRIVING UNTIL MID MORNING...LOWERED THE PRECIPITATION PROBABILITIES BETWEEN 08.12Z AND 08.15Z. FROM SATURDAY NIGHT THROUGH TUESDAY...A SERIES OF SHORT WAVE TROUGHS WILL EJECTED OUT OF THE LONG WAVE OVER THE WESTERN UNITED STATES. THIS WILL BRING ROUND OF SHOWERS AND THUNDERSTORMS INTO THE AREA. WITH STILL SOME TIMING DIFFERENCES AND SUBTLE DIFFERENCES IN THE MODELS...STAYED WITH THE MODEL CONSENSUS. TOWARD THE MIDDLE OF NEXT WEEK...IT LOOKS LIKE THERE WILL BE A PATTERN SHIFT AS THE UPPER LEVEL FLOW BECOMES NORTHWEST AND WEST ACROSS THE EASTERN UNITED STATES. LOOKS LIKE HIGHS MAY RANGE FROM THE UPPER 40S TO MID 50S...AND LOWS WILL RANGE FROM THE MID 30S TO MID 40S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 655 AM CDT WED MAY 7 2014 THROUGH 07.1330Z STRONG TO SEVERE THUNDERSTORMS WILL AFFECT KRST. THE MAIN THREAT WITH THESE THUNDERSTORMS WILL BE LARGE HAIL. WITH THE WEAKENING OF THE LOW LEVEL JET...EXPECT THE SHOWERS AND THUNDERSTORMS ALONG AND NORTH OF INTERSTATE 90 TO DISSIPATE BY 07.15Z. WHILE BOTH THE GFS AND NAM SOUNDINGS SUGGEST MVFR CEILINGS THROUGH TONIGHT. THE RAP SOUNDINGS SHOW THAT CEILINGS WILL REMAIN VFR. LOOKING AT CEILINGS AROUND THE REGION...THE RAP IS VERIFYING THE BEST...SO TRENDED THE TAFS THAT WAY. FOR TONIGHT...THE MESO MODELS SUGGEST THAT ADDITIONAL SHOWERS AND THUNDERSTORMS WILL FIRE WELL NORTH OF THE TAF SITES...THUS... WENT DRY WITH VFR CEILINGS. && .HYDROLOGY... ISSUED AT 425 AM CDT WED MAY 7 2014 FLOODING CONTINUES ALONG THE MAIN STEM OF THE MISSISSIPPI RIVER...WITH LOCATIONS CRESTING FROM NORTH MCGREGOR. SHOWERS AND THUNDERSTORMS ON THURSDAY AND THURSDAY NIGHT WILL PRODUCE ANYWHERE FROM A HALF INCH TO ONE INCH. THIS WILL LIKELY SLOW THE FALL FOR LOCATIONS NORTH OF MCGREGOR...AND MAY INCREASE CRESTS SLIGHTLY SOUTH OF MCGREGOR. CHECK OUT THE LATEST HYDROLOGIC STATEMENTS FOR THE DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...BOYNE HYDROLOGY...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
425 AM CDT WED MAY 7 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM CDT WED MAY 7 2014 AT 3 AM...WATCHING 2 AREAS OF CONVECTION. THE FIRST IS LOCATED OVER EAST CENTRAL WISCONSIN. MEANWHILE THE OTHER ONE IS LOCATED BETWEEN SIOUX FALLS SOUTH DAKOTA AND FAIRMONT MINNESOTA. BOTH OF THESE ARE LOCATED ON THE EASTERN EDGE STRONG 700 MB MOISTURE CONVERGENT AREA. IN ADDITION...THEY ARE LOCATED ONE THE NORTHERN PERIPHERY OF 1000 J/KG MOST UNSTABLE CAPE. THE ARW...NMM...HOP WRF AND SPC WRF SUGGEST THAT THE LATTER AREA OF CONVECTION WILL MOVE EAST ALONG THE INTERSTATE 90 CORRIDOR THIS MORNING. EARLIER IN THE NIGHT THE HRRR SUGGESTED A SIMILAR SCENARIO...BUT WITH ITS LATEST RUN IT HAS BACKED AWAY FROM THIS SOLUTION. HOWEVER THIS SCENARIO DOES NOT MAKE A LOT OF SENSE...SO BACKED AWAY FROM FOLLOWING IT. TRENDED THE PRECIPITATION FORECAST FOR TODAY TOWARD A BLEND OF ARW...NMM...HOP WRF AND SPC WRF. HOWEVER I AM A BIT CONCERNED THAT AS IT MOVES EAST THAT THE NOCTURNAL JET WILL WEAKEN AND THAT THE CONVECTION COULD DISSIPATE BEFORE IT GETS INTO OUR AREA. IF THE CONVECTION DOES HAPPEN TO GET INTO OUR AREA...THE SPC RAP SUGGESTS THAT EFFECTIVE SHEAR WILL INCREASE OVER 40 KNOTS THROUGH 07.14Z. THIS COULD RESULT IN THE DEVELOPMEMT OF SOME ELEVATED SUPER CELLS. WE WILL HAVE TO MONITOR THIS OVER THE NEXT COUPLE OF HOURS. FOR LATER THIS MORNING AND AFTERNOON...MANY OF THE MESO MODELS AND AND NAM SUGGEST THAT THE AREA WILL REMAIN DRY. THIS IS A RESULT OF AN ELEVATED MIXED LAYER BEING BROUGHT ISENTROPICALLY OFF OF THE SOUTHERN PLAINS. THIS LAYER FORMS A STRONG 800 TO 600 MB CAP ACROSS THE FORECAST AREA. MEANWHILE THE GFS CONTINUES TO TRY AND DEVELOP STRATIFORM PRECIPITATION BELOW THE CAP. THIS LOOKS VERY UNLIKELY BECAUSE ITS SATURATED THE AIR MASS BELOW 800 MB TOO MUCH. DUE TO THIS...STAYED WITH A DRY FORECAST FOR THE TIME PERIOD. TONIGHT...MANY OF DETERMINISTIC RUNS ARE GENERATING PRECIPITATION ACROSS MUCH OF THE FORECAST AREA. HOWEVER BUFKIT SOUNDINGS CONTINUE TO SHOW A FAIRLY STRONG CAP ALONG AND SOUTH OF INTERSTATE 94. THIS IS GOOD AGREEMENT WITH WHAT SHOWS UP IN THE ARW AND SPC WRF. DUE TO THIS...WENT WITH MUCH LOWER POPS THAN WHAT NORMALLY WOULD BE EXPECTED SOUTH OF INTERSTATE 94. IF THUNDERSTORMS DID DEVELOP...IT LOOKS TO BE SO HIGH /BASES OF 2 TO 3 KM/ THAT YOUR SHEAR IS GREATLY DECREASED TO LESS 25 KNOTS...SO THERE WILL NOT BE SUPERCELLS. HOWEVER THE CAPE PROFILE IS MUCH FATTER THAN THIS MORNING AND THIS COULD POTENTIALLY RESULT IN SOME LARGE HAIL. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 425 AM CDT WED MAY 7 2014 ON THURSDAY AND THURSDAY NIGHT...THE 07.00Z MODELS CONTINUE TO SHOW THAT A PLUME OF SUBTROPICAL MOISTURE WILL SURGE NORTHWARD AHEAD OF THE LONG WAVE TROUGH. EMBEDDED WAVES IN THIS FLOW WILL RESULT IN SHOWERS AND THUNDERSTORMS WHICH WILL USE UP MUCH OF THE CAPE PRIOR TO THE ARRIVAL OF A MUCH MORE FAVORABLE SHEAR PROFILE. DUE TO THIS...STILL THINKING THAT THE BEST SEVERE WEATHER THREAT WILL REMAIN WEST OF INTERSTATE 35. WITH THIS PLUME NOT ARRIVING UNTIL MID MORNING...LOWERED THE PRECIPITATION PROBABILITIES BETWEEN 08.12Z AND 08.15Z. FROM SATURDAY NIGHT THROUGH TUESDAY...A SERIES OF SHORT WAVE TROUGHS WILL EJECTED OUT OF THE LONG WAVE OVER THE WESTERN UNITED STATES. THIS WILL BRING ROUND OF SHOWERS AND THUNDERSTORMS INTO THE AREA. WITH STILL SOME TIMING DIFFERENCES AND SUBTLE DIFFERENCES IN THE MODELS...STAYED WITH THE MODEL CONSENSUS. TOWARD THE MIDDLE OF NEXT WEEK...IT LOOKS LIKE THERE WILL BE A PATTERN SHIFT AS THE UPPER LEVEL FLOW BECOMES NORTHWEST AND WEST ACROSS THE EASTERN UNITED STATES. LOOKS LIKE HIGHS MAY RANGE FROM THE UPPER 40S TO MID 50S...AND LOWS WILL RANGE FROM THE MID 30S TO MID 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1141 PM CDT TUE MAY 6 2014 SAW ONE BAND OF SHRA/TS DEVELOP EAST OF KLSE EARLIER THIS EVENING...BUT THAT HAS SINCE MOVED INTO EAST CENTRAL WI. FAIRLY QUIET AT THE MOMENT UPSTREAM PER RADAR MOSAIC AND SURFACE OBSERVATION IN ADVANCE OF A WARM FRONT LIFTING NORTHWARD OUT OF THE CENTRAL PLAINS. MODELS PUSHING THE WARM FRONTAL BOUNDARY INTO THE AREA WEDNESDAY...TO ALONG I-94 BY WEDNESDAY EVENING. A FEW OF THE MODELS STILL DEVELOPING SHRA/TS ACTIVITY OVERNIGHT WITH SURGE OF MOISTURE/LIFT OUT AHEAD OF THE FRONT...BUT STILL A FAIR AMOUNT OF UNCERTAINTY THOUGH BETWEEN THE MODELS ON COVERAGE OF THIS SHRA/TS ACTIVITY AND WHETHER KLSE/KRST WILL BE AFFECTED. WILL MAINTAIN VCSH/VCTS IN THE TAFS IN THE 06-13Z TIMEFRAME. OTHERWISE...VFR CONDITIONS EXPECTED. BACKED OFF ON MVFR STRATOCUMULUS IN THE MORNING DUE TO LACK OF WIDESPREAD PRECIPITATION AND BOUNDARY LAYER MOISTENING. PLAN ON VFR CONDITIONS THROUGH THE REST OF THE PERIOD AS WELL WITH ANY CONVECTION ASSOCIATED WITH THE WARM FRONT EXPECTED TO REMAIN NORTH OF THE KRST/KLSE TAF SITES. && .HYDROLOGY... ISSUED AT 425 AM CDT WED MAY 7 2014 FLOODING CONTINUES ALONG THE MAIN STEM OF THE MISSISSIPPI RIVER...WITH LOCATIONS CRESTING FROM NORTH MCGREGOR. SHOWERS AND THUNDERSTORMS ON THURSDAY AND THURSDAY NIGHT WILL PRODUCE ANYWHERE FROM A HALF INCH TO ONE INCH. THIS WILL LIKELY SLOW THE FALL FOR LOCATIONS NORTH OF MCGREGOR...AND MAY INCREASE CRESTS SLIGHTLY SOUTH OF MCGREGOR. CHECK OUT THE LATEST HYDROLOGIC STATEMENTS FOR THE DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...DAS HYDROLOGY...BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
858 PM MDT THU MAY 8 2014 .UPDATE... ISSUED AT 833 PM MDT THU MAY 8 2014 LATEST RADAR LOOP WAS SHOWING SHOWERS CONTINUING TO FLARE UP ACROSS EXTREME SOUTHEAST WYOMING MAINLY ALONG AND EAST OF THE LARAMIE RANGE DUE TO A COOL DOME ALOFT AND UPSLOPE FLOW PROMOTING THE INSTABILITY. THE MODELS ARE CONTINUING TO ADVERTISE THIS DOME OF COOL AIR SHIFTING EAST OVERNIGHT WHICH SHOULD ALLOW FOR MORE SUBSIDENCE TO MOVE INTO SOUTHEAST WYOMING. HOWEVER...I AM A LITTLE LEARY ABOUT YANKING THE POPS COMPLETELY UNTIL 3AM...SINCE WE DO HAVE SOMEWHAT OF AN UPSLOPE COMPONENT. THE OTHER CONCERN WE HAVE TONIGHT IS THE FOG POTENTIAL WHERE THE SNOWFALL TOOK PLACE LAST NIGHT. SNOW/CLOUD DISCRIMINATOR PRODUCT FROM CIRA IS SHOWING THE BULK OF THE SNOW OCCURRED IN THE NORTHERN PANHANDLE WHICH LOOKS TO BE THE MOST FAVORABLE REGION FOR FOG DEVELOPING OVERNIGHT. THIS AREA IS ALSO BEGIN TO CLEAR OUT WITH SOME PATCHY FOG BEGINNING TO SHOW UP IN DAWES AND BOX BUTTE COUNTIES. HRRR ALSO SHOWS GOOD INDICATIONS OF THIS FOG PERSISTING THROUGH THE NIGHT. WE MAY ALSO HAVE TO WATCH THIS AREA FOR POTENTIAL FOG ADVISORY. OTHERWISE...CURRENT FORECAST APPEARS TO BE ON TRACK. UPDATE ISSUED AT 415 PM MDT THU MAY 8 2014 SENDING OUT A QUICK UPDATE TO INCREASE PRECIPITATION CHANCES ACROSS ALBANY...LARAMIE AND KIMBALL COUNTIES AS A BATCH OF RAIN AND EMBEDDED THUNDER MOVES EAST THROUGH THAT REGION. THE BULK OF THE CONVECTION SHOULD END AFTER SUNSET. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 330 PM MDT THU MAY 8 2014 SNOW HAS COME TO AN END ACROSS THE NORTHERN NE PANHANDLE THIS AFTN AS AN INTENSE SFC LOW AND ASSOCIATED MID LEVEL TROWAL HAVE EXITED THE AREA TO THE NORTHEAST. ONLY CONCERN IN THE NEAR TERM WILL BE THE POTENTIAL FOR CONVECTIVE ACTIVITY THROUGH THIS EVE. CLEARING SKIES ON THE BACK SIDE OF THE SYSTEM HAVE ALLOWED TEMPS TO WARM NICELY...INTO THE MIDDLE TO UPPER 40S ACROSS MUCH OF SOUTHEAST WY. MID LEVELS ARE QUITE COLD WITH LAPS SOUNDINGS SHOWING H5 TEMPS TO -20C...SO A GREAT SETUP FOR INSTABILITY RAIN SHOWERS. LATEST RADAR LOOP SHOWS THIS ACTIVITY CONFINED TO THE I80 CORRIDOR...AND BELIEVE THIS TREND WILL CONTINUE THROUGH THE EARLY EVE AS MESOSCALE MODELS SHOW LIFTED INDICES AROUND ZERO HERE. WE HAVE SEEN SOME LIGHTNING STRIKES ALONG THE CO BORDER IN THE PAST FEW HOURS...BUT MODEST CONVECTIVE INSTABILITY PROFILES SUGGEST MOST OF THIS ACTIVITY WILL BE OF THE SHOWER VARIETY. LARGE SCALE SUBSIDENCE WILL BUILD INTO THE AREA BY LATE EVE BENEATH WEAK SHORTWAVE RIDGING...ENDING THE THREAT FOR SHOWERS AND STORMS. NEXT CHANCE FOR CONVECTION WILL BE FRI AFTN AHEAD OF THE NEXT WEAK MID LEVEL SHORTWAVE EMBEDDED WITHIN ZONAL FLOW ALOFT. WENT AHEAD AND ADDED ISO THUNDER TO THE GRIDS AS THE LATEST GFS IS SHOWING 500 TO 750 J/KG OF SBCAPE. NAM BUFKIT SOUNDINGS SHOW SOME WEAK ELEVATED INSTABILITY AS WELL. NO CONCERNS FOR SEVERE WEATHER THOUGH. DESPITE SOME HIGH LEVEL CLOUD COVER LIKELY MOVING OVERHEAD WITH INCREASING 700-300 MILLIBAR MOISTURE...DOWNSLOPE WARMING SHOULD AID IN WIDESPREAD 60S FOR HIGHS EAST OF THE LARAMIE RANGE. MOST OF THE SNOW IN THE PANHANDLE SHOULD BE MELTED BY THEN...SO EXPECT A MINIMAL IMPACT TO TEMPS. ATTENTION THEN SHIFTS TO THE POTENTIAL FOR YET ANOTHER MAJOR STORM FOR THE WEEKEND. MODELS ARE IN GREAT AGREEMENT SHOWING A VIGOROUS UPPER-LEVEL TROUGH DIGGING INTO THE GREAT BASIN ON SAT. MOIST SOUTH WEST FLOW ALOFT AND A FEW DISTURBANCES EMANATING FROM THE PARENT TROUGH SUGGESTS ANOTHER GOOD CHANCE FOR SHOWERS AND STORMS...THOUGH WESTERLY LOW LEVEL FLOW SUGGESTS THE BULK OF THIS ACTIVITY WILL BE ALONG AND WEST OF THE LARAMIE RANGE. LIMITED MOISTURE SHOULD KEEP SEVERE WEATHER AT BAY THIS TIME AROUND...THOUGH SHEAR PROFILES WILL BE RATHER STRONG. GFS...NAM...AND ECMWF ALL SHOW A STRONG SFC COLD FRONT BLASTING SOUTH ACROSS THE CWA LATE SAT NIGHT. NORTH TO NORTH EAST SFC UPSLOPE FLOW AND LARGE SCALE VERTICAL ASCENT WILL ALMOST CERTAINLY FAVOR PCPN DEVELOPMENT...BUT THE BIG QUESTION NOW IS EXACTLY WHERE. THE GFS IS STILL THE OUTLIER WITH HEAVY PCPN BANDING FROM NORTH CENTRAL CO INTO THE SOUTHERN PANHANDLE...WHILE THE ECMWF AND GEM ARE MUCH FURTHER NORTH WITH THE FRONTOGENESIS BAND AND WOULD AFFECT A LARGER PART OF OUR CWA. REGARDLESS...H7 TEMPS FALL TO BETWEEN -8C AND -12C IN THE POST FROPA AIR MASS WITH 1000-500 MB THICKNESSES RANGING FROM 540 TO 549 DM FROM NORTHWEST TO SOUTHEAST AT 12Z SUN. THIS WOULD SUPPORT SNOW... AND A LOT OF IT IF MODELED QPF VALUES ARE ANYTHING CLOSE TO WHAT ACTUALLY TRANSPIRES. IT IS A LITTLE UNSETTLING THAT THE ECMWF HAS BEEN CONSISTENT OVER THE LAST COUPLE OF RUNS WITH THE PLACEMENT OF THE HEAVIEST SNOW. IT WAS ALSO THE FIRST TO LOCK ON TO THIS PARTICULAR STORM EVOLUTION. IT IS MUCH TOO EARLY FOR ANY SORT OF HEADLINE...BUT CONFIDENCE IS HIGH THAT A PORTION OF OUR CWA WILL SEE SIGNIFICANT WINTER WEATHER. WENT AHEAD AND ISSUED A SPECIAL WEATHER STATEMENT HIGHLIGHTING THE POTENTIAL STORM FOR PUBLIC AWARENESS. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 330 PM MDT THU MAY 8 2014 FORECAST CHALLENGES EARLY IN THE EXTENDED PERIOD WILL FOCUS ON THE SPRING STORM SYSTEM MOVING ACROSS THE CENTRAL ROCKIES AND PLAINS. THERE ARE TIMING...STRENGTH AND POSITION DIFFERENCES WITH EMERGENCE OF THE UPPER LOW FROM THE CENTRAL GREAT BASIN SUNDAY. THE GFS IS TRENDING SLIGHTLY FASTER AND NORTH OF THE ECMWF. AT 12Z SUNDAY...GFS PROGS THE 554DM LOW OVER EAST CENTRAL UT...WHILE THE ECMWF/S 550DM LOW IS SITUATED IN SOUTHWEST UT. THE PRIMARY SURFACE LOW SHOWN BY THE GFS AT THE SAME TIME IS OVER FAR SOUTHWEST CO AND THE ECMWF/S LOW IS ALONG THE AZ/UT BORDER. BY 00Z MONDAY...GFS 559DM LOW IS OVER FAR WESTERN CO AND THE ECWMF 554DM LOW IS OVER SOUTH CENTRAL UT. THE SURFACE LOW REDEVELOPS AND INTENSIFIES OVER THE NORTHERN TX PANHANDLE IN THE GFS...AND SOUTHWEST CORNER OF KS IN THE ECMWF. THE 1000-500MB THICKNESS GRADIENT RAPIDLY TIGHTENS AND INTENSE LOW/MID LEVEL ASCENT DEVELOPS. COLD AIR AT LOW LEVELS WILL BE ADVECTED SOUTH INTO THE STORM SYSTEM ALONG THE EASTERN SLOPES OF THE ROCKIES...LOWERING SNOW LEVELS SIGNIFICANTLY. PLENTY OF MOISTURE WRAPPING INTO THE LOW...MID LEVEL QG FORCING AND LOW LEVEL UPSLOPE WILL RESULT IN SIGNIFICANT PRECIPITATION....WITH SNOW LEVELS POSSIBLY DROPPING AS LOW AS 4500 FT. A CONSENSUS OF THE GFS AND ECMWF QPF FROM 00Z SUNDAY THROUGH 12Z MONDAY INDICATES BETWEEN 1.5 AND 2.5 INCHES OF LIQUID PRECIPITATION. CONSENSUS MODEL SNOW ACCUMULATIONS PROJECT BETWEEN 12 AND 20 INCHES FOR THE MOUNTAINS... 4 TO 10 INCHES LOWER ELEVATIONS ALONG AND SOUTH OF I-80...AND 1 TO 4 INCHES NORTH OF I-80. STILL PLENTY OF UNCERTAINTY WITH THIS STORM AND WILL CONTINUE TO EVALUATE TRENDS AS THE STRENGTH AND TRACK OF THE STORM SYSTEM CAN CHANGE FROM ONE MODEL RUN TO THE NEXT. IT WILL BE MUCH COLDER SUNDAY AS 700MB TEMPERATURES FALL TO -5C TO -10C. HIGH TEMPERATURES SUNDAY WILL RANGE FROM THE 20S MOUNTAINS TO THE 40S OVER THE PLAINS. THESE TEMPERATURES MAY BE NEED TO BE LOWERED WITH LATER FORECASTS. GUSTY NORTHEAST WINDS OF 20 TO 30 MPH WILL ADD TO THE CHILL. IF YOU BELIEVE THE GFS...SNOW WILL BEGIN TO TAPER OFF FROM WEST TO EAST MONDAY MORNING. THE ECMWF KEEPS THE UPPER TROUGH AXIS ALONG THE FRONT RANGE WHICH WOULD PROLONG THE PRECIPITATION INTO MONDAY NIGHT. NORTHWEST FLOW ALOFT WILL PREVAIL TUESDAY THROUGH THURSDAY. THERE ARE INDICATIONS THAT IT WILL NOT BE DRY STABLE FLOW AS THERE WILL BE SOME MINOR DISTURBANCES WHICH MAY GENERATE SHOWERY EPISODES. TEMPERATURES MODERATE TOWARD SEASONAL NORMALS BY THE END OF THE PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON) ISSUED AT 653 PM MDT THU MAY 8 2014 RAIN SHOWERS WITH A FEW EMBEDDED TSTORMS REMAIN A THREAT FOR WESTERN AND SOUTHERN PORTIONS OF WYOMING THIS EVENING THROUGH ROUGHLY 03Z. AREAS OF FOG/STRATUS LOOK TO DEVELOP MAINLY IN THE NORTHERN NEBRASKA PANHANDLE AND NORTH PLATTE RIVER VALLEY OVERNIGHT. IN PARTICULAR...MVFR TO IFR CIGS AND VSBYS ARE EXPECTED AT KCDR AND KAIA...WITH SOME POTENTIAL TO REACH KBFF. CONDITIONS IN THESE LOCATIONS WILL IMPROVE SHORTLY AFTER SUNRISE. ELSEWHERE...VFR CONDITIONS WILL PREVAIL. WINDS WILL DIMINISH TONIGHT...BUT WILL INCREASE LATE IN THE MORNING AND REMAIN GUSTY THROUGH FRIDAY AFTERNOON. WEST TO SOUTHWEST WINDS GUSTING 25 TO 35 KTS ARE EXPECTED ALONG AND WEST OF THE LARAMIE RANGE...WITH 20 TO 25 KTS FURTHER EAST. && .FIRE WEATHER... ISSUED AT 300 PM MDT THU MAY 8 2014 NO FIRE WEATHER CONCERNS. MILD CONDITIONS ARE EXPECTED FOR FRIDAY AND SATURDAY...BUT WINDS AND RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN WELL OUTSIDE OF CRITICAL THRESHOLDS. ANOTHER SPRING STORM WILL AFFECT THE AREA SUNDAY AND MONDAY...BRINGING COOLER TEMPERATURES AND WIDESPREAD RAIN AND SNOW. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...REC SHORT TERM...HAMMER LONG TERM...JAMSKI AVIATION...RJM FIRE WEATHER...HAMMER
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
631 AM MDT WED MAY 7 2014 .UPDATE... ISSUED AT 602 AM MDT WED MAY 7 2014 WILL ADD SOME FOG TO THE FORECAST GRIDS THROUGH MID MORNING. FOG HAS FORMED MAINLY ALONG THE LEADING EDGE OF A COLD FRONT THIS MORNING...GENERALLY FROM LARAMIE TO CHEYENNE TO KIMBALL. SOME LOCALLY DENSE FOR IS POSSIBLE. THE FOG SHOULD LIFT INTO A STRATUS DECK BY MID MORNING. ALSO OF NOTE IS THE 06Z MODEL RUNS. BOTH THE NAM AND GFS PUSH THE SURFACE COLD FRONT ABOUT 30 TO 40 MILES FARTHER SOUTH THAN THE 00Z RUNS. THE IMPLICATIONS OF THIS ARE MANY. FIRST...THIS WILL SHIFT THE SEVERE THREAT SLIGHTLY SOUTHWARD...AND WILL GREATLY REDUCE THE THREAT FOR TORNADIC ACTIVITY IN THE CWA THIS AFTERNOON. WILL STILL HAVE TO KEEP AN EYE ON THE LOCATION OF THE SURFACE FRONT THIS AFTERNOON...BUT LOOKS LIKE THE MAIN TORNADO THREAT WILL BE JUST SOUTH OF THE NEBRASKA BORDER. THE OTHER IMPACT WILL BE ON SNOW AMOUNTS. A DEEPER COLD BOUNDARY LAYER IS MORE FAVORABLE FOR RAIN CHANGING TO SNOW TONIGHT. IT MAY BE JUST COLD ENOUGH GIVEN HIGH PRECIPITATION RATES FOR A GOOD DEAL OF SNOW ACCUMULATIONS...WITH SNOW ADVISORIES AND WINTER STORM WARNINGS A MUCH GREATER LIKELIHOOD TONIGHT INTO THURSDAY MORNING. MODELS ARE ALSO SLOWER WITH THE DEPARTURE OF THIS SYSTEM WITH COULD ALSO INCREASE SNOW ACCUMULATIONS. LATEST OBSERVATIONS ACROSS NORTHEAST WYOMING SHOWING TEMPERATURES IN THE LOWER TO MIDDLE 30S...SO THE 06Z MODEL RUNS MAY BE ON TO SOMETHING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM MDT WED MAY 7 2014 WOW...LOTS OF WEATHER CONCERNS TODAY...FROM RIVER FLOODING TO FLASH FLOODING...TO SEVERE THUNDERSTORMS WITH TORNADOES POSSIBLE... TO THE POTENTIAL FOR HEAVY SNOW TONIGHT. THIS MORNING WILL BE RELATIVELY QUIET WITH SHOWERS DEVELOPING AS AN UPPER LEVEL SYSTEM APPROACHES AND COULD SEE A FEW THUNDERSTORMS BY LATER THIS MORNING. THE MAIN CHANCES FOR THUNDERSTORMS WILL HOLD OFF UNTIL THIS AFTERNOON. THERE IS A HIGH PROBABILITY FOR SOME OF THESE THUNDERSTORMS TO BECOME SEVERE...MAINLY OVER FAR SOUTHEAST WYOMING AND INTO NEBRASKA PANHANDLE. OF COURSE ALL THIS IS PREDICATED ON THE EXACT TRACK OF THE UPPER LEVEL LOW. AT THIS TIME IT APPEARS THERE WILL BE SUFFICIENT UPPER LEVEL FORCING AND MID LEVEL INSTABILITY FOR SEVERE THUNDERSTORMS. INTO THE SOUTHERN NEBRASKA PANHANDLE...MODELS SHOWING MOST UNSTABLE CAPE VALUES 2000 J/KG ALONG AND JUST NORTH OF A STALLED FRONTAL BOUNDARY. ALSO LOOKING AT 50 TO 60 KTS OF BULK SHEAR WHICH IS MORE THAN ENOUGH FOR ROTATING SUPERCELL THUNDERSTORMS. ASSUMING THE FRONT IS LOCATED NEAR THE INTERSTATE 80 CORRIDOR...SHOULD SEE STORMS FIRE NEAR THE BOUNDARY AND THEN LIFT NORTHWARD UNDER STRONG SOUTHERN MIDLEVEL WINDS. NOT 100 PERCENT CONFIDENT ON THE EXACT LOCATION OF THE FRONT...BUT IT SHOULD BE BETWEEN INTERSTATE 80 AND THE COLORADO BORDER. THERE IS THE POSSIBILITY FOR TORNADIC ACTIVITY ALONG THIS FRONTAL BOUNDARY FROM ABOUT MID AFTERNOON INTO EARLY EVENING. AIR TEMPERATURES WILL BE RATHER COOL...BUT THAT WILL NOT NECESSARILY PRECLUDE TORNADO DEVELOPMENT. STRONG LOW LEVEL SHEAR AND LIFTED CONDENSATION LEVELS ONLY A FEW THOUSAND FEET AGL ARE FAVORABLE FOR TORNADIC DEVELOPMENT. THE TORNADO THREAT WILL BE CONFINED TO AREAS ALONG AND NEAR THE BOUNDARY...MAINLY BETWEEN PINE BLUFF TO KIMBALL TO SIDNEY. ALSO WORTH MENTIONING THE THE POTENTIAL FOR VERY LARGE HAIL. THE STORM PREDICATION CENTER HAS HATCHED HAIL FOR STONES UP TO 2 INCHES IN DIAMETER. THIS SEEMS VERY REASONABLE GIVEN MIDLEVEL CAPE VALUES AND SHEAR PARAMETERS. SHOULD CAPE VALUES END UP BEING MUCH HIGHER...BASEBALL OR LARGER HAIL WOULD COME INTO PLAY. ANOTHER THING TO CONSIDER IS FREEZING LEVELS ARE LOW...SO FALLING HAIL WILL NOT SEE MUCH MELTING. FOR FLASH FLOOD POTENTIAL IN THE SOUTHERN NEBRASKA PANHANDLE LATER TODAY... SEE THE HYDROLOGY DISCUSSION BELOW. LATER TONIGHT THE ATTENTION TURNS TO THE POTENTIAL FOR SNOW...AND POSSIBILITY HEAVY SNOW. CONFIDENCE NOT HIGH WITH THE CURRENT SNOW FORECAST AS THERE AREA MORE VARIABLES AT PLAY WITH THIS SPRING STORM SYSTEM. WHERE AND HOW MUCH SNOW FALLS WILL BE LARGELY DEPENDENT ONLY A FEW DEGREES DIFFERENCE IN ACTUALLY AIR TEMPERATURES...AND DEPENDENT ON PRECIPITATION RATES. MODELS HAVE TRENDED SLIGHTLY COLDER...WHICH MAKES THE POTENTIAL FOR HEAVY SNOW A GREATER POSSIBILITY...EVEN INTO THE PLAINS IN THE NEBRASKA PANHANDLE. MODELS SHOWING A PERIOD OF MODERATE RAIN ON THE BACKSIDE OF THE AREA OF LOW PRESSURE. THIS PRECIPITATION COULD EASILY WETBULB DOWN TO THE POINT WHERE SNOW ACCUMULATES AS RATES OF AN INCH OR MORE PER HOUR. THE WARM GROUND WILL INITIALLY MELT MUCH OF THE SNOW...BUT WITH SEVERAL HOURS OF HIGH SNOW RATES...SOME PLACE CERTAINLY COULD PUSH SNOW ADVISORY LEVELS...AND NOT DISCOUNTING WARNING CRITERIA BEING REACHED AT A FEW LOCATIONS. GIVEN LARGE UNCERTAINTY AND WITH THE THREAT FOR SEVERE WEATHER INTO EARLY THIS EVENING...DID NOT ISSUE ANY HEADLINES. WILL HAVE TO SEE WHAT WHAT THE 12 MODEL RUNS SHOW...BUT VERY WELL MAY NEED WINTER WEATHER HEADLINES AT SOME POINT. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 330 AM MDT WED MAY 7 2014 UNSETTLED WEATHER CONTINUES IN THE LONG TERM WITH A PRETTY GOOD WINTER SYSTEM POSSIBLE SUNDAY INTO MONDAY. STARTING OFF ON FRIDAY...FAST MOVING SHORTWAVE MOVES THROUGH NORTHERN PORTIONS OF WYOMING WITH SHOWERS CONTINUING OVER OUR WESTERN MOUNTAINS. TEMPERATURES LOOK WARM ENOUGH FOR MAINLY RAIN SHOWERS. WILL NEED TO WATCH THIS FRIDAY AS THE RAIN COULD EXACERBATE SNOW MELT OVER THE SNOWY AND SIERRA MADRE RANGES. BY SATURDAY AFTERNOON...A PRETTY STRONG PACIFIC LOW PRESSURE SYSTEM LOOKS TO MOVE INTO SOUTHERN IDAHO. A FRONTAL BOUNDARY BEGINS TO SAG SOUTH INTO CENTRAL WYOMING LATE SATURDAY NIGHT AND ENDS UP DOWN NEAR THE COLORADO/WYOMING BORDER BY SUNDAY MORNING. PRETTY COLD 700MB TEMPERATURES BEHIND THE FRONT...GFS SHOWING -6 TO -8C 700MB TEMPERATURES ACROSS MOST OF SOUTHEAST WYOMING SUNDAY MORNING. UPPER SHORTWAVE SUNDAY MORNING TRACKS INTO NORTHERN UTAH AND ACROSS NORTHERN COLORADO DURING THE DAY SUNDAY. NEW ECMWF VERY SIMILAR TO THE GFS ON THE TRACK OF THIS SHORTWAVE...IT IS EVEN COLDER THAN THE GFS THOUGH WITH 700MB TEMPERATURES OF -8 TO -10C BY SUNDAY AFTERNOON. WENT MUCH COLDER THAN GUIDANCE ON TEMPERATURES SUNDAY AND BOOSTED POPS OVER GUIDANCE AS WELL. PROBABLY NOT COLD ENOUGH THOUGH AND LATER SHIFTS WILL NEED TO LOWER EVEN MORE. THIS SYSTEM FINALLY PUSHES SOUTHEAST SUNDAY NIGHT INTO MONDAY. LOOKS LIKE A PRETTY COLD MORNING MONDAY WITH LOWS IN THE 20S FOR MANY LOCATIONS. SHOULD START TO SEE A REBOUND IN TEMPERATURE THOUGH MONDAY AFTERNOON AS 700MB TEMPERATURES CLIMB TO ABOVE FREEZING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 627 AM MDT WED MAY 7 2014 WIDESPREAD LOW CLOUDS AND FOG THIS MORNING THROUGH AT LEAST 16-17Z TIME FRAME BEFORE CLOUDS BEGIN TO BREAK UP. LATEST HRRR FORECAST DOING VERY WELL ON THIS STRATUS AND FOG AND GENERALLY FOLLOWED ITS GUIDANCE. CONVECTION STILL LOOKS TO BE A GOOD POSSIBILITY THIS AFTERNOON AND EARLY EVENING. THEN TONIGHT...WITH COLDER TEMPERATURES...WE SHOULD SEE RAIN TURN OVER TO SNOW WITH IFR/LIFR RETURNING. && .FIRE WEATHER... ISSUED AT 408 AM MDT WED MAY 7 2014 NO FIRE WEATHER CONCERNS THROUGH EARLY NEXT WEEK. VERY WET LATER TODAY THROUGH TONIGHT. RAIN AND SNOW FOR MUCH OF THE AREA. COULD SEE SNOW ACCUMULATIONS IN SOME PLACES. DRIER FOR FRIDAY AND SATURDAY WITH A FEW SHOWERS HERE OR THERE...THEN ANOTHER LARGE STORM SYSTEM POSSIBLE SATURDAY NIGHT AND SUNDAY WITH SNOW POSSIBLE ESPECIALLY OVER SOUTHEAST WYOMING. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH LATE TONIGHT FOR WYZ119. NE...FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH LATE TONIGHT FOR NEZ020-021-054-055. && $$ UPDATE...SML SHORT TERM...SML LONG TERM...CLAYCOMB AVIATION...CLAYCOMB FIRE WEATHER...SML
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1110 PM MDT TUE MAY 6 2014 .SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY NIGHT) ISSUED AT 320 PM MDT TUE MAY 6 2014 HIGH CLOUD COVER LIMITED SFC HEATING OVER MUCH OF THE PLAINS THROUGH MIDDAY...HOWEVER MUCH BETTER CLEARING IS NOW SEEN OVER THE CWA. DEWPOINTS ACROSS THE PLAINS ARE LARGELY IN THE 40S SO THERE IS DECENT LLVL MOISTURE. WOULD BE MOST CONCERNED ABOUT STRONG TO MARGINALLY SEVERE STORMS IN CONVERSE COUNTY. THE RUC INDICATES AROUND 1000 J/KG OF SFC BASED CAPE THROUGH THE EARLY EVENING ALONG WITH GOOD DEEP LAYER SHEAR OF 50 KTS. THE HRRR MODELS HAS ALSO BEEN CONSISTENT AT SHOWING A DISCRETE CELL JUST TO THE NORTH OF CONVERSE COUNTY. NOT AS MUCH INSTABILITY (AROUND 500 J/KG OF CAPE) IS FCSTED OVER THE WESTERN NEBRASKA PANHANDLE...SO NOT AS CONCERNED ABOUT STRONG STORMS OUT THERE. ANY STORMS THAT DO DEVELOP SHOULD WEAKEN BY LATE EVENING. ONE MORE MILD NIGHT ACROSS THE CWA AHEAD OF THE UPPER TROUGH THAT IS LOCATED OVER UTAH. SFC LOW STRENGTHENS OVER NORTHEASTERN COLORADO BY LATE WED MORNING WITH NORTHEAST WINDS DEVELOPING ACROSS THE PLAINS. WEATHER CONCERN FROM LATE MORNING WED THROUGH THE AFTN WILL BE ON THE SEVERE THREAT OVER THE EXTREME SOUTHEASTERN PART OF THE CWA. SPC HAS A SLIGHT RISK OVER THE SOUTHERN HALF OF THE PANHANDLE. CAPE VALUES INCREASE TO AROUND 1000 J/KG BY 18Z ALONG INTERSTATE 80 IN THE SOUTHERN PANHANDLE. 0-3 KM HELICITY IS CLOSE TO 300 ALONG 0-6 KM SHEAR VALUES OF 55 KTS. THINKING THAT HAIL WILL BE THE PRIMARY THREAT...BUT CAN NOT RULE OUT A WEAK TORNADO WITH THE GOOD LLVL SHEAR. THE WINDOW FOR SVR WEATHER SHOULD NOT EXTEND MUCH LATER THAN THE EARLY AFTN HOWEVER...AS WINDS BECOME NORTHERLY BY LATE AFTN AND INSTABILITY IS ON THE DECREASE BEHIND THE FRONT. THE MODELS HAVE BEEN CONSISTENT WITH THE TRACK OF THE UPPER LEVEL SYSTEM. IT PUSHES INTO NORTHEASTERN COLORADO ON WED EVENING AND THEN BEGINS TO CLOSE OFF OVER SOUTHWESTERN NEBRASKA BY LATE WED NIGHT. A TROWAL IS SHOWN PUSHING INTO THE WESTERN NEBRASKA PANHANDLE BETWEEN 00-12Z THURS. EXCELLENT DEEP LAYER UPWARD MOTION IS DEPICTED LATE WED AFTN AND INTO THE EVENING OVER THE PLAINS OF SOUTHEAST WY...WHICH THEN SHIFTS INTO THE NEBRASKA PANHANDLE AFTER 06Z. THUS...STILL EXPECTING A WIDESPREAD HEAVY QPF EVENT FOR MUCH OF THE PLAINS. HPC HAS THE PANHANDLE IN A SLIGHT RISK FOR EXCEEDING FLASH FLOOD GUIDANCE. MUCH OF THE PRECIP WILL FALL AS RAIN OVER THE PLAINS...HOWEVER A TRANSITION TO SNOW COULD OCCUR AFTER AROUND 09Z FOR ELEVATIONS ABOVE 5000 FT OR SO. THE GFS HAS BEEN CONSISTENTLY THE WARMEST IN THE POST FRONTAL AIRMASS AS IT KEEPS SFC WET BULB TEMPS ABOVE 37F TO THE EAST OF THE LARAMIE RANGE THROUGH WED NIGHT...WHEREAS THE NAM IS CLOSE TO FREEZING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 320 PM MDT TUE MAY 6 2014 MEDIUM RANGE MODEL GUIDANCE IS IN EXCELLENT AGREEMENT WITH A POTENT UPPER-LEVEL SHORTWAVE AND ASSOCIATED SFC LOW EJECTING NORTHEAST INTO THE CENTRAL PLAINS EARLY IN THE PERIOD. BOTH THE GFS AND NAM SHOW A DISTINCT TROWAL FEATURE ON THE BACK SIDE OF THE LOW OVER THE WESTERN PANHANDLE. THIS COMBINED WITH GOOD QG ASCENT WILL MOST LIKELY YIELD A CONTINUATION OF MODERATE TO HEAVY PCPN FROM THE PANHANDLE INTO EAST CENTRAL WY BETWEEN 12-18Z THU. WITH 700-850 TEMPS BETWEEN 0 AND -5 C...WOULD EXPECT RAIN TO AT LEAST MIX WITH SNOW ESPECIALLY OVER THE HIGHER TERRAIN NEAR THE PINE RIDGE. NOT THINKING RATES WILL BE HIGH ENOUGH FOR SIGNIFICANT ACCUMULATIONS...BUT STILL CANNOT RULE OUT A FEW INCHES OF SNOW OVER OUR NORTHERN ZONES IN THE DEEPER COLD AIR. BEST FORCING AND MOISTURE SHIFTS NORTH AND EAST OF THE CWA BY EARLY AFTN...WITH PCPN CHANCES DIMINISHING THEREAFTER. QUASI-ZONAL FLOW ALOFT RETURNS TO THE AREA ON FRI AND SAT WITH A FEW NUISANCE DISTURBANCES EMBEDDED WITHIN. DESPITE SOME MODEST COOLING ALOFT FROM TIME TO TIME...WESTERLY DOWNSLOPE FLOW WILL GIVE WAY TO SEASONABLE TEMPS IN THE LOW TO MID 60S OVER THE PLAINS. COULD SEE A FEW SHOWERS OR RUMBLES OF THUNDER EACH AFTERNOON OVER MUCH OF THE AREA. GFS CAPES ARE GENERALLY LESS THAN 100 J/KG...BUT WITH STEEP MID LEVEL LAPSE RATES IN EXCESS OF 8.5 DEG C/KM...A STRAY LIGHTNING STRIKE CAN NEVER BE RULED OUT. BIG QUESTIONS COME INTO PLAY FOR THE SECOND HALF OF THE WEEKEND AND INTO EARLY NEXT WEEK. THE ECMWF REMAINS CONSISTENT WITH A CLOSED LOW AND TROUGH DIGGING INTO THE FOUR CORNERS WITH SFC CYCLOGENESIS OVER THE PLAINS OF EASTERN CO. LATEST GEM SHOWS A VERY SIMILAR FEATURE... SO THIS WILL BEAR WATCHING. 12Z GFS TELLS A DIFFERENT TALE...WITH A VERY PROGRESSIVE AND POSITIVELY TILTED OPEN WAVE MOVING QUICKLY ACROSS THE PLAINS. MADE VERY FEW CHANGES TO THE PREVIOUS FCST GIVEN THESE DIFFERENCES...BUT POTENTIAL EXISTS FOR ANOTHER MAJOR STORM LATE IN THE PERIOD IF THE ECMWF WERE TO VERIFY. SNOW WOULD AGAIN BE A GOOD POSSIBILITY AS H7 TEMPS PLUNGE AS LOW AS -10C. REGARDLESS OF WHICH MODEL IS CORRECT...COOLER AND BREEZY CONDITIONS SEEM TO BE A GOOD BET LATE IN THE WEEKEND. TRIMMED A FEW DEGREES OFF FCST HIGHS ON SUN AFTN AS WIDESPREAD CLOUD COVER AND COLD AIR ALOFT DO NOT LEND CREDENCE TO HIGHS NEAR 60F. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING) ISSUED AT 1108 PM MDT TUE MAY 6 2014 THE MAIN CONCERN WITH TAF ISSUANCE IS THE POTENTIAL FOR THUNDERSTORMS ALONG WITH IFR/MVFR CEILINGS DEVELOPING OVER THE PANHANDLE OVERNIGHT. THUNDERSTORMS WILL GENERALLY BE ISOLATED IN NATURE UNTIL 3AM OVER THE SOUTHERN AND CENTRAL PANHANDLE WITH ANOTHER CHANCE OF STRONG TO SEVERE TSTORMS ON WEDNESDAY EAST OF THE LARAMIE RANGE. OTHERWISE...LOW CIGS AND NEAR IFR CONDITIONS WILL BEGIN TO DEVELOP AROUND 08Z ACROSS THE NEBRASKA PANHANDLE DUE TO MOIST UPSLOPE FLOW...AND MAY PUSH INTO FAR SOUTHEAST WYOMING. PATCHY FOG IS ALSO POSSIBLE EARLY WEDNESDAY MORNING. && .FIRE WEATHER... ISSUED AT 320 PM MDT TUE MAY 6 2014 VERY DRY CONDITIONS EXIST TO THE WEST OF THE LARAMIE RANGE THIS AFTERNOON WITH RELATIVE HUMIDITY VALUES AT 10-15 PERCENT. SOUTHWEST WINDS ARE ALSO GUSTING TO 30 MPH. HOWEVER...FUELS ARE NOT SUPPORTIVE OF FIRE GROWTH WITH THE GREENUP IN PROGRESS. A STORM SYSTEM WILL MOVE ACROSS THE REGION ON WEDNESDAY AND WEDNESDAY NIGHT WITH AN EXCELLENT CHANCE OF WETTING PRECIPITATION...ESPECIALLY ALONG AND EAST OF THE LARAMIE RANGE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...FINCH LONG TERM...HAMMER AVIATION...CLAYCOMB FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
858 PM PDT THU MAY 8 2014 .SYNOPSIS...A WEAK PACIFIC STORM SYSTEM WILL BRING AREAS OF LIGHT RAIN TO THE SAN FRANCISCO BAY AREA AND PORTIONS OF THE CENTRAL COAST THROUGH TONIGHT...WITH A FEW LIGHT SHOWERS POSSIBLY PERSISTING IN NORTHERN MONTEREY COUNTY INTO FRIDAY MORNING. DRY CONDITIONS WILL RETURN THIS WEEKEND ALONG WITH BRISK NORTHWEST WINDS AND NEAR NORMAL TEMPERATURES. A SIGNIFICANT WARMING TREND IS FORECAST EARLY NEXT WEEK AS AN UPPER LEVEL RIDGE BUILDS ALONG THE WEST COAST AND WINDS TURN OFFSHORE. && .DISCUSSION...AS OF 8:55 PM PDT THURSDAY...A WEAK AND DISSIPATING FRONTAL BOUNDARY HAS BEEN PUSHING INTO OUR AREA SINCE LATE AFTERNOON. LIGHT RAIN HAS BEEN REPORTED THROUGHOUT THE NORTH BAY...BUT RAIN REPORTS SOUTH OF THE GOLDEN GATE HAVE BEEN MUCH LESS COMMON. RAINFALL AMOUNTS HAVE MOSTLY BEEN LESS THAN A TENTH OF AN INCH...ALTHOUGH ISOLATED PORTIONS OF THE NORTH BAY HAVE PICKED UP BETWEEN A QUARTER AND A HALF INCH. EXPECT RAINFALL TO TAPER OFF IN THE NORTH BAY THROUGH THE REMAINDER OF THE EVENING. AREAS OF SPRINKLES OR LIGHT RAIN MAY CONTINUE SOUTH OF THE GOLDEN GATE THROUGH THE REMAINDER OF THE NIGHT AS THE WEAK FRONTAL BOUNDARY PUSHES TO THE SOUTHEAST. THE 00Z NAM CONTINUES TO DROP LIGHT PRECIP ACROSS NORTHWEST MONTEREY COUNTY INTO FRIDAY MORNING. THIS SEEMS REASONABLE GIVEN THE MOIST NORTHWEST FLOW THAT IS FORECAST TO PERSIST INTO TOMORROW MORNING. A RECENT FORECAST UPDATE INCLUDED ADDING A SLIGHT CHANCE OF SHOWERS TO NORTHWEST MONTEREY COUNTY THROUGH LATE FRIDAY MORNING. DRY CONDITIONS ARE EXPECTED TO RETURN TO THE ENTIRE AREA BY FRIDAY AFTERNOON AS INCREASING NORTHWESTERLY FLOW ADVECTS A DRIER AIRMASS INTO THE REGION. NORTHWEST WINDS WILL GUSTS LOCALLY AS HIGH AS 35 MPH ALONG THE IMMEDIATE COAST BY LATE TOMORROW AFTERNOON. BRISK NORTHWEST WINDS WILL THEN CONTINUE FOR COASTAL AREAS INTO SATURDAY AND SATURDAY EVENING AS A STRONG SURFACE HIGH BUILDS OFF THE NORTHERN CALIFORNIA COAST. TEMPERATURES TOMORROW AND SATURDAY WILL BE NEAR NORMAL TO SLIGHTLY BELOW NORMAL. ON SATURDAY NIGHT THE SURFACE HIGH OFFSHORE IS FORECAST TO BUILD INLAND TO OUR NORTH AND EAST...CAUSING WINDS TO VEER TO THE NORTH AND INCREASE IN THE HILLS BY LATE SATURDAY NIGHT. THIS WILL BRING A MUCH DRIER AIRMASS INTO THE REGION AND BEGIN TO INCREASE FIRE WEATHER CONCERNS. WINDS WILL REMAIN LOCALLY STRONG AND GUSTY IN THE HILLS THROUGH SUNDAY MORNING AND THEN GRADUALLY SUBSIDE SUNDAY AFTERNOON AND EVENING. IN ADDITION TO OFFSHORE NORTHERLY FLOW ON SUNDAY...THE AIRMASS ALOFT WILL START TO WARM AS AN UPPER RIDGE BEGINS TO BUILD JUST OFFSHORE. THE RESULT WILL BE A SHARP RISE IN TEMPERATURES ON SUNDAY. HIGHS WILL BE ABOUT TEN DEGREES WARMER ON SUNDAY COMPARED TO SATURDAY...AND AS MUCH AS 15 DEGREES WARMER AT THE COAST. SUNDAY WILL DEFINITELY BE THE BETTER BEACH DAY THIS WEEKEND. THE WARMING TREND THAT WILL BEGIN ON SUNDAY WILL CONTINUE THROUGH THE FIRST HALF OF NEXT WEEK AS LIGHT OFFSHORE FLOW PERSISTS AND THE UPPER RIDGE CONTINUES TO STRENGTHEN NEAR THE WEST COAST. 850 MB TEMPERATURES ARE FORECAST TO CLIMB TO 23-24 DEG C OVER PORTIONS OF OUR AREA BY THE MIDDLE OF NEXT WEEK. THIS MEANS THE AIRMASS OVER OUR AREA WILL BE AT LEAST A FEW DEGREES C WARMER THAN IT WAS DURING OUR LAST HEAT EVENT AT THE END OF APRIL AND FIRST FEW DAYS OF MAY. THUS...EXPECT INLAND TEMPERATURES TO CLIMB INTO THE 90S BY TUESDAY AND WEDNESDAY WITH A FEW OF THE WARMER INLAND LOCATIONS EXPECTED TO REACH THE CENTURY MARK BY MIDWEEK. LIGHT OFFSHORE FLOW WILL MEAN COASTAL AREAS WILL BE VERY WARM AS WELL...BUT JUST HOW WARM DEPENDS ON THE STRENGTH AND PERSISTENCE OF OFFSHORE FLOW WHICH IS A BIT DIFFICULT TO PREDICT THIS FAR IN ADVANCE. THE POTENTIAL CERTAINLY EXISTS FOR SOME 90S IN COASTAL AREAS BY MIDWEEK. && .AVIATION...AS OF 5:10 PM PDT THURSDAY...FOR 00Z TAFS. WEAK FRONT IS MOVING INTO THE NORTH BAY AT THIS TIME WITH SOME SPOTTY SHOWERS ACROSS THE REGION. SOMEWHAT SURPRISINGLY WINDS HAVE TURNED SOUTHEAST AT THE BUOYS AND SOME AIRPORTS. NONE OF THE MESOSCALE MODELS REALLY CAPTURED THIS BUT LATEST RAP RUN DOES AND SHOWS WINDS SWITCHING BACK TO MORE WESTERLY BY ABOUT 05-06Z THIS EVENING SO WOULD EXPECT SOUTHERLY WINDS AT KSFO FOR THE EVENING HOURS. CIGS LOOK TO GENERALLY STAY AROUND 2000 FEET OR HIGHER TONIGHT...EARLIER RAIN AT UKIAH WAS ACCOMPANIED BY BKN023. THE FRONT SHOULD BE GONE BY SUNRISE AND BRISK NW WINDS AND DRYING SHOULD MIX CIGS OUT FAIRLY EARLY WITH STRONG NW WINDS TOMORROW AFTERNOON POSSIBLE AT KSFO. VICINITY OF KSFO...EXPECT SOUTHERLY WINDS TO CONTINUE THIS EVENING AS WEAK FRONT MOVES THROUGH WITH WIND GUSTS IN EXCESS OF 15 KT. CIGS SHOULD STAY ABOVE 2000 FEET IN GENERAL WITH POSSIBLE LIGHT RAIN SHOWERS THIS EVENING. LOW TO MEDIUM CONFIDENCE. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...FRONT IS TO THE NORTH AND LOW CLOUDS WILL INCREASE AFTER 03Z ALONG THE COAST...THEN STAY IN PLACE OVERNIGHT WITH SOME VICINITY SHOWERS/DRIZZLE POSSIBLE AT KMRY. CLEARING SHOULD OCCUR BY 18Z FRIDAY WITH GUSTY NW WINDS FRIDAY AFTERNOON. MEDIUM CONFIDENCE. && .MARINE...AS OF 1:20 PM PDT THURSDAY...GENERALLY LIGHT BUT OCCASIONALLY GUSTY NORTHWEST WINDS ARE EXPECTED TONIGHT AS A COLD FRONT APPROACHES THE CENTRAL CALIFORNIA COAST. THIS WEAK COLD FRONT WILL BRING A SLIGHT CHANCE OF SHOWERS TO THE COASTAL WATERS THROUGH THIS EVENING AS IT MOVES ACROSS THE REGION. WINDS WILL BEGIN TO INCREASE AND SEA CONDITIONS WILL DETERIORATE ONCE AGAIN FRIDAY AFTERNOON AS THE SURFACE PRESSURE GRADIENT STRENGTHENS ALONG THE CALIFORNIA COAST. && .MTR WATCHES/WARNINGS/ADVISORIES... .NONE && $$ PUBLIC FORECAST: DYKEMA AVIATION: RWW MARINE: CW VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1247 AM CDT FRI MAY 9 2014 .DISCUSSION... 818 PM CDT FOR EVENING UPDATE... SHOWER/THUNDERSTORM COVERAGE AND INTENSITY PLAYING OUT AS EARLIER DISCUSSED...WITH CONVECTION GENERALLY STRUGGLING AS IT MOVES INTO NORTH CENTRAL IL. LOSS OF DIURNAL HEATING AND ASSOCIATED LOW-LEVEL INSTABILITY HAS DECREASED MARGINAL SEVERE THREAT...THOUGH WILL CONTINUE TO MONITOR CELLS MOVING OUT OF WEST-CENTRAL IL FOR ANY STRONGER CORES THAT MIGHT STILL BE ABLE TO PRODUCE SOME SMALL HAIL OR MARGINAL WIND GUSTS. OTHERWISE...AREA OF RAIN AND EMBEDDED THUNDER OVER EASTERN MISSOURI IS EXPECTED TO SHIFT NORTHEAST INTO OUR REGION AFTER MIDNIGHT IN ASSOCIATION WITH MID-LEVEL SHORT WAVE AND INCREASING MOISTURE TRANSPORT ON 40-50 KT 850 HPA JET. REGIONAL RADAR MOSAIC AND ORIENTATION OF MOIST PLUME OVERNIGHT SUGGESTS FOCUS WILL BE IN OUR CENTRAL/SOUTHEASTERN CWA...THOUGH LARGER SCALE HEIGHT FALLS AHEAD OF DEEP UPPER TROUGH LIFTING INTO THE UPPER MIDWEST AND APPROACH OF SURFACE COLD FRONT TOWARD MORNING SHOULD BOTH WORK TO INCREASE COVERAGE OF SHOWERS/THUNDERSTORMS OVER NORTHWESTERN CWA AS WELL PRE-DAWN FRIDAY MORNING. EXTENT OF CLOUDINESS AND MORNING PRECIP RAISES QUESTIONS ABOUT EXTENT OF THUNDERSTORM/SEVERE THREAT FRIDAY AFTERNOON...THOUGH FRONT SLOWS UP IN THE AFTERNOON ACROSS NORTHWEST IN/EAST CENTRAL IL AND INDICATES BEST CHANCES FOR PRECIP/THUNDER FRIDAY AFTERNOON MAINLY ACROSS ABOUT THE SOUTHEAST 1/3 OF THE FA. HAVE MADE SOME ADJUSTMENTS TO HOURLY POP/WX GRIDS TO PROVIDE A LITTLE MORE DETAIL IN TIMING AND PLACEMENT OF EXPECTED ROUNDS OF PRECIP THROUGH FRIDAY...WITH POPS LOWERED FROM THE WEST/NORTHWEST BEHIND THE FRONT ON FRIDAY AND GRADIENT FROM NO POPS NORTHWEST TO LIKELY POPS IN OUR SOUTHEAST TIGHTENED UP. HAVE ALSO FOCUSED MENTION OF LOCALLY HEAVY RAINFALL FOR LATE TONIGHT/EARLY FRIDAY MORNING OVER CENTRAL/SOUTHEAST COUNTIES AS INDICATED ABOVE. UPDATED GRIDS...ZFP/LFP ALL ALREADY AVAILABLE. RATZER //PREV DISCUSSION... 312 PM CDT MAIN CONCERN FOR THE AREA REMAINS THE CHANCES FOR THUNDERSTORMS. FOR THE REMAINDER OF THE AFTERNOON AND INTO EARLY THIS EVENING...CONDITIONS SHOULD REMAIN QUIET AS THE AREA REMAINS IN A CAPPED WARM SECTOR. THE WARM FRONT HAS PUSHED WELL NO THE NORTH WHILE A COLD FRONT IS WELL TO THE WEST...EXTENDING FROM DEEPENING LOW PRESSURE OVER WRN IA/ERN NE SOUTHWEST THROUGH CNTRL KS/WRN OK. AS LONG AS THE ENVIRONMENT OVER THE LOCAL AREA REMAINS CAPPED...THE CHANCES FOR ANY PCPN WILL BE LIMITED. CURRENTLY...THE PRIMARY THUNDERSTORM THREAT IS INVOF THE COLD FRONT/SFC LOW WHERE SPC HAS ISSUED THE FIRST WATCH OF THE DAY OVER WRN IA/NWRN MN. AS SFC TEMPERATURES RISE INTO THE UPPER 80S ANTICIPATE THAT THE CAP WILL ERODE WITH TIME THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. HOWEVER...SOME DRIER AIR IS MIXING DOWN TO THE SURFACE THIS AND SFC DEWPOINTS HAVE DROPPED INTO THE UPPER 50S...BUT EXPECT THAT DEWPOINTS WILL REBOUND BACK INTO THE 60S THIS EVENING. SFC BASED INSTABILITY WILL BE ON THE INCREASE WHILE THE SFC LOW TRACKS TO THE WRN GREAT LAKES OVERNIGHT TONIGHT AND THE COLD FRONT PUSHES INTO NWRN IL. STRONG WARM ADVECTION IN THE WARM SECTOR AND LOW LEVEL FORCING WITH THE COLD FRONT COMBINED WITH UPPER LEVEL FORCING AS THE REGION WILL BE UNDER THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAM...WILL PROVIDE THE FOCUS FOR THE DEVELOPMENT OF STRONG TO...POTENTIALLY...SEVERE THUNDERSTORMS ACROSS NRN IL THROUGH THE NIGHT. WHILE THERE MAY STILL BE A CHANCE FOR DISCRETE SUPERCELLS TO DEVELOP AHEAD OF THE COLD FRONT...THE MORE LIKELY CONVECTIVE MODE TONIGHT IS SHAPING UP TO BE MORE LINEAR...AS THE CONVECTIVE ACTIVITY TO THE WEST CONSOLIDATES INTO LINES. THUS...THE MORE LIKELY SEVERE THREAT SHOULD BE LARGE HAIL AND STRONG DAMAGING WINDS. HEAVY RAINFALL WILL ALSO BE A CONCERN WITH THE THUNDERSTORMS TONIGHT WITH PWATS FORECAST TO BE ARND 1.7 INCHES. HOWEVER...WITH THE FRONTAL SYSTEM STEADILY PROGRESSIVE TO THE EAST...DO NOT ANTICIPATE SIGNIFICANT ECHO TRAINING. SO...LOCALLY HEAVY RAINFALL MAY LEAD TO URBAN FLOODING CONCERNS...DO NOT ANTICIPATE A WIDESPREAD FLASH FLOOD THREAT. THE SHORT RANGE MODEL GUIDANCE IS RELATIVELY CONSISTENT ON THE STEADY PROGRESSION OF THE COLD FRONT...CLEARING THE ERN PORTIONS OF THE CWA BY EARLY TOMORROW AFTERNOON...THOUGH SOME LINGERING SHOWERS ARE POSSIBLE INTO THE LATE AFTERNOON HOURS...ESPECIALLY FOR THE NWRN INDIANA COUNTIES. FOLLOWING THE PASSAGE OF THE COLD FRONT...A PERIOD OF RELATIVE CALM IS EXPECTED FOR FRIDAY NIGHT AND SATURDAY AS WEAK HIGH PRESSURE SPREADS OVER THE MIDWEST. TEMPERATURES FOR FRIDAY AND SATURDAY SHOULD MODERATE INTO THE LOWER TO MIDDLE 70S. BRISK SWLY FLOW PERSISTING ON FRIDAY SHOULD ALLOW THE WARMER AIR TO PENETRATE ALL THE WAY TO THE LAKE FRONT...BUT FOR SATURDAY...A WEAK SFC PRESSURE GRADIENT AND RELATIVELY LIGHT WINDS SHOULD ALLOW FOR A LAKE BREEZE TO DEVELOP. WITH ANOTHER LOW DEVELOPING OVER THE CNTRL PLAINS AND HIGH PRESSURE OVER THE SERN CONUS...SFC WINDS SHOULD BE PREVAILING SLY TO SWLY...SO...THE LAKE BREEZE SHOULD ASSUME A NW-SE ORIENTATION AND LIKELY ONLY MOVE INLAND FROM CHICAGO NORTHWARD. WHILE MUCH OF THE CWA ENJOYS TEMPERATURES BACK IN THE MIDDLE 70S ON SATURDAY...THE LAKEFRONT LOCATIONS FROM CHICAGO TO WAUKEGAN SHOULD SEE HIGHS ONLY IN THE LOWER TO MIDDLE 60S. THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL COME BY SATURDAY EVENING AS THE AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS THROUGH THE UPPER MIDWEST AND DRAGGING ANOTHER COLD FRONT ACROSS THE AREA. THIS SYSTEM IS NOT LOOKING QUITE AS DYNAMIC AS THE SYSTEM EXPECTED THIS EVENING...SO...THE CHANCES FOR MORE SEVERE WEATHER ARE LOW. A SRN STREAM SYSTEM LIFTING OUT OF THE SRN ROCKIES BY SATURDAY NIGHT WILL DEVELOP A WAVE ON THE SRN END OF THE FRONT. THIS WAVE IS FORECAST TO RIPPLE ALONG THE BOUNDARY TO THE NORTHEAST...WHICH WILL HELP TO SLOW THE OVERALL PROGRESSION OF THE SYSTEM AND A STRUNG OUT FRONTAL SYSTEM IS EXPECTED TO EXTEND FROM THE RED RIVER VALLEY INTO THE WRN GREAT LAKES BY SUNDAY NIGHT. WITH THE FRONT NOT EXPECTED TO PUSH EAST OF THE AREA UNTIL TUESDAY MORNING...THERE WILL BE AN EXTENDED CHANCE FOR SHOWERS AND THUNDERSTORMS FROM LATE SATURDAY NIGHT THROUGH TUESDAY MORNING. FOR THE LONGER RANGE FORECAST PERIOD...FROM TUESDAY THROUGH THURSDAY...FOLLOWING THE PASSAGE OF THE COLD FRONT AND THE ASSOCIATED LOW...THERE WILL STILL BE LINGERING CHANCES FOR SHOWERS WITH A SERIES OF NRN STREAM SHORT WAVES DROPPING OUT OF CANADA RIGHT ON THE HEELS OF THE EXITING SYSTEM. WITH SOME UNCERTAINTY TO THE EXACT TIMING OF THIS SERIES OF SHORTWAVES...WILL CARRY AT LEAST CHANCE POPS THROUGH THE EXTENDED PERIOD. WITH THE TRAIN OF SHORTWAVES CARVING OUT A LONG WAVE TROUGH OVER THE GREAT LAKES AND MIDWEST...TEMPERATURES FOR TUESDAY THROUGH THURSDAY SHOULD BE BACK TO WELL BELOW NORMAL. HIGHS FOR TUESDAY THROUGH THURSDAY ARE EXPECTED TO BE IN THE LOWER TO MIDDLE 60S WITH EVEN SOME UPPER 50S POSSIBLE ALONG THE LAKEFRONT. OVERNIGHT LOWS THROUGH THE EXTENDED PERIOD SHOULD ONLY BE IN THE 40S. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * PERIODS OF SHRA THROUGH THE REST OF THE NIGHT...WITH TSRA ALSO POSSIBLE AT TIMES. LOW VIS DOWN UNDER 3 SM POSSIBLE IN THE HEAVIEST SHOWERS. * GUSTY SOUTHWESTERLY WINDS TODAY. KJB //DISCUSSION...UPDATED 06Z... THE MAIN FORECAST CONCERN IS THE THREAT FOR CONVECTIVE ACTIVITY AT ACROSS THE EASTERN TERMINALS THROUGH AROUND DAY BREAK. SHOWERS CONTINUE TO DEVELOP ACROSS CENTRAL ILLINOIS AS MOISTURE CONTINUES TO STREAM NORTHWARD AHEAD OF LOW PRESSURE ACROSS MN. THESE DEVELOPING SHOWERS ARE EXPECTED TO TREK NORTHEASTERLY...AND WILL IMPACT...MAINLY THE EASTERN TERMINALS ACROSS MUCH OF NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA OVER THE NEXT SEVERAL HOURS THIS MORNING. THIS ACTIVITY WILL RESULT IN SHORT PERIODS OF LOW MVFR TO IFR VISIBILITIES IN HEAVY RAIN AND I WOULD NOT BE SURPRISED TO HAVE SOME THUNDERSTORMS MOVE OVER OR NEAR THE TERMINALS. THINGS SHOULD QUIET DOWN AROUND OR SHORTLY AFTER DAY BREAK TODAY...WITH THE MAIN THREAT FOR CONVECTION SHIFTING EAST OF THE TERMINALS DURING THE DAY. WINDS WILL REMAIN GUSTY OUT OF THE SOUTHWEST...WITH GUSTS LIKELY UP AROUND 25 KT THROUGH MUCH OF THE DAY. A COOL FRONT WILL SHIFT ACROSS THE AREA BY LATE AFTERNOON/EARLY EVENING...WITH WINDS EXPECTED TO BECOME MORE WESTERLY AND ABATE BY EVENING. KJB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH WITH WIND TRENDS. * HIGH IN SHRA OVERNIGHT...LOW IN VCTS/PREVAILING TSRA AT TERMINALS. KJB //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... SATURDAY...DAYTIME VFR...LAKE BREEZE WIND SHIFT POSSIBLE. SHRA/TSRA POSSIBLE OVERNIGHT. SUNDAY...PERIODS OF SHRA/TSRA POSSIBLE. SOUTHERLY WINDS. MONDAY...PERIODS OF SHRA/TSRA POSSIBLE. SOUTH TO SOUTHWEST WINDS. TUESDAY AND WEDNESDAY...CHANCE SHRA. RC && .MARINE... 218 PM CDT A WARM FRONT DRAPED ACROSS THE NORTHERN PART OF THE LAKE LATE THIS AFTERNOON WILL SHIFT NORTH OF THE LAKE THIS EVENING...YIELDING SOUTHERLY WINDS ACROSS THE ENTIRE LAKE. GUSTS AROUND 25 KT...AT TIMES POSSIBLY REACHING 30 KT BRIEFLY...WILL CONTINUE ACROSS ILLINOIS AND INDIANA NEAR SHORE AREAS THROUGH TONIGHT AND INTO FRIDAY. STORMS LOOK LIKELY LATE TONIGHT INTO FRIDAY MORNING...A FEW OF WHICH COULD BE GUSTY. AS THE LOW PRESSURE DRIVING THE SOUTHERLY WINDS MOVES FROM IOWA THIS AFTERNOON THROUGH ONTARIO ON FRIDAY IT WILL STEER A COLD FRONT OVER LAKE MICHIGAN ON FRIDAY NIGHT. THIS FRONT WILL BE WEAKENING THOUGH AND ONLY BRIEFLY TURN THE WINDS WEST-SOUTHWEST BEFORE TURNING BACK SOUTHERLY THIS WEEKEND. THE NEXT AREA OF LOW PRESSURE WILL NEAR THE LAKE DURING LATE SUNDAY INTO MONDAY. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 PM FRIDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1106 PM CDT Thu May 8 2014 .DISCUSSION... ISSUED 835 PM CDT Thu May 8 2014 Convection continues to make slow progress over west central IL this evening, now advancing along and just east of I-55. Had a couple of reports of wind gusts of 50 to 60 mph with the storms late this afternoon but those were few and far between. With the loss of daytime heating, our instability parameters are not very impressive across central IL this evening with CAPE values over most of the area now down below 1000 j/kg. Short term models suggest as low level jet increases to our southwest later this evening, we should see more widespread rainfall across the forecast area during the early morning hours along with mild temperatures. Have already sent out an update to address the storms moving into west central IL earlier this evening, but will send out another update by 900 pm to address the current thinking on the timing of the rain into eastern IL later this evening. Smith && .AVIATION... ISSUED 1103 PM CDT Thu May 8 2014 Main forecast concern includes coverage of showers and storms across the forecast area during the early morning hours and the affects on cigs as the latest model data continues to suggest cigs deteriorating to MVFR during the early morning hours. Another band of rain and storms was pushing NNE across southern IL late this evening and it appears the bulk of that area of rain should stay south of our TAF sites. Meanwhile, additional showers and storms should increasing in coverage over the next several hours which should help to bring cigs down to MVFR over most of the area. Still looks as if cigs will drop to between 1500-2500 feet aftr 08z acrs most of the area, with locally lower cigs for a brief time if any of our TAF sites are affected by a heavier shower or storm. The MVFR cigs should gradually give way to VFR cigs by late morning as a cold front shifts across our area. Storm redevelopment is expected tomorrow afternoon but it still appears that will be east and south of the TAF sites. Surface winds will remain out of a southerly direction at 12 to 17 kts overnight with some higher gusts possible in and near any thunderstorms. Winds will veer more into the southwest and then west during the afternoon with speeds in the 15 to 20 kt range with gusts up to 30 kts possible in the afternoon, especially if we can get some sunshine to break through. VFR conditions are expected across the entire forecast area tomorrow evening thru 06z. Smith && .PREV DISCUSSION... ISSUED 258 PM CDT Thu May 8 2014 Temperatures warming nicely across the forecast area today, with gusty south-southwest winds and mainly some high clouds. Mostly in the mid 80s, although some 90 degree temperatures reported at Champaign and Rantoul at 2 pm. Convection developing as expected west of the Mississippi River, with one cluster over Minnesota/Iowa along the warm front, and the second developing over western Missouri just ahead of the cold front. Both fronts are tied into a surface low over northeast Nebraska. Initial forecast concerns are with thunderstorm trends through Friday including severe threat, followed by timing of showers/storms for much of the first half of next week. SHORT TERM...Tonight through Friday Night: Latest mesoscale analysis showing CAPE`s of 1000-1500 J/kg over the forecast area, with the cap eroding along the Mississippi River. Latest HRRR has the storms reaching the Illinois River valley by around 6 pm and I-57 toward 9-10 pm. Areas west of I-55 most likely to see any severe weather as the instability will be decreasing by the time the storms make it further east. Hail/wind remains the primary concern with the storms. Secondary line of showers/storms immediately ahead of the front will begin to move in after midnight, but think the severe threat will be be over by that point. Extent of overnight convection will dictate where the severe threat is for Friday. Areas south of I-70 would be most likely as the front comes in and with outflows from the earlier convection around, but additional instability would likely have to come during the afternoon in between periods of storms. Will mention categorical PoP`s over 80% across the southeast third of the forecast area through the day, with not the rain not fully moving out of the southeast CWA until closer to midnight. Further west, will largely go dry west of I-55 during the afternoon. LONG TERM...Saturday through Thursday: Short period of dry weather on tap for Saturday as a narrow ridge axis slides by, but next wave will be approaching from the Plains. Have added some slight chance PoP`s in the afternoon west of I-55, but main period of convection will develop Saturday night. Will introduce likely PoP`s late Saturday night across about the northwest 2/3 of the forecast area, lingering into Sunday across the north as remnants of an MCS move across the area. The forecast from Sunday night into Monday night is more of a challenge. The GFS is much faster than the ECMWF or Canadian models by surging a cold front through the area Monday night, while the latter models are close to 24 hours slower. This slower solution would keep a good part of Sunday night and Monday dry. This appears to be tied into phasing of the long wave trough across the Rockies Sunday night, with the GFS featuring a more progressive wave and the ECMWF cutting off a low over the northern Dakotas for a time early next week. Am trending the blended model grids on the slower side, but have not completely eliminated any PoP`s Monday/Tuesday. Deep upper trough over the central U.S. to provide a period of cooler weather for the middle of the week. Will see highs only in the 60s much of the Tuesday-Thursday period. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
302 AM MDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 258 AM MDT FRI MAY 9 2014 EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS CONFLUENT FLOW ENTERING ROCKIES OVER PLAINS ON BACK SIDE OF DEPARTING TROUGH...WITH WEAK SHORTWAVE ENERGY UPSTREAM NEAR DIFLUENT FLOW OVER GREAT BASIN. AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER OUR CWA WITH STATIONARY FRONT ALONG FRONT RANGING AND COLD FRONT OVER OK/TX PANHANDLES. RADAR SHOWS SOME VIRGA AND VERY LIGHT SPRINKLES LINGERING AS A SHORTWAVE IS EJECTING ACROSS THE SOUTHERLY PLAINS. WITH SUBSIDENCE BUILDING IN FROM THE NORTH THIS ACTIVITY LIKELY WONT LAST LONG. TEMPS HAVE DROPPED INTO THE MID 30S ACROSS THE WEST...AND WE COULD SEE A FEW LOW TEMPS AROUND FREEZING BY SUNRISE. A WEAK SHORTWAVE TROUGH WILL PASS NORTH OF THE CWA THIS AFTERNOON AND EVENING AND MAY COMBINE WITH AFTERNOON/EVENING INSTABILITY TO PRODUCE A FEW THUNDERSTORMS OVER NE COLORADO. VERY DRY LOW LEVELS WOULD LIMIT PRECIP REACHING THE SURFACE. DECIDED TO KEEP SMALL AREA OF OUR NW CWA WITH ISO THUNDER AROUND 00Z AND OTHERWISE LIMITED PRECIP MENTION TO SPRINKLES. SEASONAL TEMPS SHOULD RETURN AS SOUTHERLY FLOW REDEVELOPS TODAY...WITH HIGHS IN THE 70S AND OVERNIGHT LOWS TONIGHT IN THE LOW-MID 40S (MAYBE A FEW SPOTS A LITTLE COLDER WEST). SATURDAY-SUNDAY NIGHT...COMPLICATED FORECAST AS THE NEXT STRONG UPPER TROUGH IS EXPECTED TO IMPACT THE CENTRAL ROCKIES AND PLAINS. SOUTHWESTERLY FLOW DEVELOPS ACROSS THE ROCKIES WHICH WOULD INITIALLY LIMIT ANY SHOWER/THUNDERSTORM CHANCES TO THE NW SATURDAY. HOWEVER BY SATURDAY NIGHT THE MAIN TROUGH BEGINS TO SLIDE EAST ALLOWING GOOD MOISTURE AND LIFT OT BUILD OVER THE CWA. BEST PRECIP CHANCES ACROSS THE CWA STILL LOOKS TO BE ON SUN/SUN NIGHT AND MODELS SHOW REASONABLE AGREEMENT ON MEASURABLE PRECIP SO I BUMP POPS INTO 60-70 RANGE FOR THOSE PERIODS. A LITTLE LESS CONFIDENT ON AREA OF BEST PRECIP...THOUGH PARTS OF THE REGION (ESPECIALLY WEST) COULD SEE DECENT LIQUID ACCUMULATION WITH THIS EVENT (0.15-0.75"). REGARDING WEATHER TYPE...VERY LIMITED INSTABILITY THROUGH MOST OF THE EVENT...SO ONLY KEPT THUNDER MENTION SATURDAY AFTERNOON/EVENING. TEMP PROFILES AND WBZ HEIGHTS WOULD INDICATE A RAIN/SNOW MIX OR A COMPLETE CHANGEOVER ACROSS THE WESTERN HALF OF THE CWA SUNDAY NIGHT. WARM GROUND TEMPS MAY LIMIT ANY SNOW ACCUMULATION (ASSUMING LIGHTER RATES). IN ADDITION TO WARM GROUND TEMPS...CONFIDENCE OF CHANGEOVER TIMING IS LOW SO I LEFT ACCUMULATION MENTION OUT OF FORECAST. I DID INCLUDE RAIN/SNOW MENTION AND A BRIEF PERIOD OF ALL SNOW AROUND SUNRISE EARLY MONDAY MORNING. WILL NEED TO WATCH HOW THIS SYSTEM EVOLVES TO ZERO IN ON THESE DETAILS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 258 AM MDT FRI MAY 9 2014 MODELS ARE STILL IN DISAGREEMENT WITH THE POSITION AND PROGRESSION OF THE UPPER LEVEL TROUGH IN THE EXTENDED. GFS STILL MOVES IT FURTHER EAST MORE QUICKLY THAN THE ECMWF. HOWEVER...THE TROUGH WILL CONTINUE TO INFLUENCE THE CWA ON MONDAY. TEMPERATURES MONDAY MORNING APPEAR COLD ENOUGH FOR LIGHT SNOW TO CONTINUE OVER EASTERN COLORADO WITH A RAIN SNOW MIX IN NORTHWEST KANSAS IN COUNTIES BORDERING EASTERN COLORADO. TEMPERATURES SHOULD WARM ENOUGH BY 15Z FOR ALL PRECIPITATION TO BE RAIN...WITH THE CHANCE FOR RAIN CONTINUING MONDAY AFTERNOON. MONDAY WILL REMAIN BREEZY AS THE TIGHT PRESSURE GRADIENT STAYS OVER THE CWA UNTIL MONDAY NIGHT WHEN IT RELAXES AND SURFACE HIGH PRESSURE SETTLES IN OVER COLORADO. TUESDAY THROUGH WEDNESDAY SHOULD REMAIN DRY AS THE UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES BECOMES MORE INFLUENTIAL IN THE HIGH PLAINS. BY THURSDAY...A SHORTWAVE TROUGH WILL ROTATE AROUND THE UPPER TROUGH OVER THE GREAT LAKES REGION SENDING A WEAK COLD FRONT THROUGH THE CWA. SHOWERS AND THUNDERSTORMS COULD DEVELOP AHEAD OF THE FRONT...SINCE THE GFS DOES HAVE A FEW HUNDRED J/KG OF CAPE OVER EASTERN COLORADO. AS PREVIOUSLY MENTIONED...THE MODELS ARE HAVING A HARD TIME COMING TO A CONSENSUS FOR ANY DAY IN THE EXTENDED...SO AM TRYING TO GET AWAY FROM GETTING TOO DETAILED FOR THUNDERSTORM POTENTIAL IN DAY 7. WELL BELOW AVERAGE TEMPERATURES CAN BE EXPECTED TO START OFF THE EXTENDED PERIOD WITH HIGHS ON MONDAY IN THE LOW TO UPPER 50S. LOWS MONDAY NIGHT WILL BE IN THE LOW 30S TO LOW 40S WITH HIGHS ON TUESDAY IN THE LOW TO MID 60S. SLIGHTLY BELOW TO NEAR NORMAL TEMPERATURES WILL TAKE OVER THROUGH THE REST OF THE EXTENDED WITH HIGHS IN THE MID 60S TO LOW 70S ON WEDNESDAY AND THURSDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1111 PM MDT THU MAY 8 2014 VFR CONDITIONS WILL PREVAIL AT MCK AND GLD THROUGH THE TAF PERIOD. LIGHT NORTH TO NORTHWEST WINDS WILL TURN SOUTHWEST BY MORNING WITH SOME LIGHT GUSTINESS DURING THE AFTERNOON AS THE LEE SURFACE TROUGH DEEPENS ALONG THE FRONT RANGE. && .FIRE WEATHER... ISSUED AT 243 AM MDT FRI MAY 9 2014 WITH WARMER TEMPS AND LOWER TD MIXING TO THE SURFACE WE COULD SEE RH VALUES WITHIN RFW CRITERIA ACROSS THE SOUTHERN PART OF OUR FORECAST AREA BOTH TODAY AND SATURDAY AFTERNOON/EARLY EVENING PERIODS. TODAY WINDS WILL BE WELL BELOW CRITERIA WITH WEAK GRADIENT IN PLACE...SO NO RFW PRODUCT ANTICIPATED. SW PRESSURE GRADIENT BEGINS TO INCREASE SATURDAY AHEAD OF DEEPENING UPPER LOW...THOUGH EVOLUTION OF SURFACE LOW AND FRONT POSITION WILL BE CRITICAL FOR WHERE WINDS WITHIN RFW CRITERIA WILL CROSS WITH LOW RH. NOT ENOUGH CONFIDENCE AT THIS POINT TO ISSUE A FIRE WEATHER WATCH FOR SATURDAY...BUT WE WILL PROBABLY NEED TO MONITOR. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...ALW AVIATION...LOCKHART FIRE WEATHER...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1202 AM CDT Fri May 9 2014 ...UPDATE TO AVIATION... .SYNOPSIS... ISSUED AT 1007 PM CDT THU MAY 8 2014 Water vapor imagery and 00Z upper air analysis indicate an upper level trough axis transitioning eastward across the Western High Plains. Meanwhile, another upper level trough is pushing ashore into the Pacific Northwest. Near the surface...a cold front extends from northeastern Kansas southwest into western Oklahoma while high pressure builds across the Northern Plains. Cool dry air is filtering southward into western Kansas with surface dewpoints falling into the 30s(F). && .SHORT TERM...(This evening through Friday) ISSUED AT 329 PM CDT THU MAY 8 2014 Chances are greatest that most of the forecast area remains dry tonight. The front has shifted far enough east that the HRRR model solutions appear more believable than the NAM model`s solution of a retreating dryline returning moisture and allowing moist deep convection. The far west central Kansas counties such as Hamilton and Stanton could see showers and isolated thunderstorms early this evening associated with convective development over eastern Colorado. Of the various HiRes models, the NMM cores suggest a PV anomaly significant enough to produce showers on the backside of the upper jet, mainly late tonight and overnight. Instability will be minimal however and probabilities have been kept very low for the overnight episode. Temperatures overnight should fall into the low 50s and seen some 40s farther west where clearing is likely by 12 UTC. Weak westerly downslope surface winds will develop on Friday as surface high pressure spreads eastward across southeast Kansas during the afternoon. Other than mid level clouds, mostly sunny conditions should prevail based on model layer RH fields. The downslope flow will promote adiabatic warming resulting in boundary layer warm advection. Models are strongly aligned for highs in the mid to upper 70s with only bias corrected solutions creating warmer highs in the low 80s in the far southwest. .LONG TERM...(Friday night through Thursday) ISSUED AT 314 PM CDT THU MAY 8 2014 The medium range models continue to show a strong upper level shortwave digging into the western states this weekend and moving out into the plains by early next week. The ECMWF, GEM and UKMET models have all been similar and tend to be slower and deeper with this wave. The GFS has been more open and progressive with this wave for several runs. However, it is showing a tendency in its operational run...as well as some of the ensemble members...to be a little slower and deeper. Upper level westerly flow over the central High Plains on Friday will gradually become more southwesterly by Saturday night as the upper wave digs into the Intermountain West. As the upper wave approaches on Sunday, a frontal boundary should moves southward into western Kansas with a surface low pressure system developing along the front. There are some model differences in the position of this front during the day Sunday. The faster GFS has it through all of western Kansas by later in the afternoon while the other models keep it farther west. This will have significant impacts on daytime high temperatures as well as where the best chance for thunderstorms will be. Given the model tendencies, will keep the front farther west with a fairly significant temperature gradient across southwest and south central Kansas. The models show 60 degree dewpoints spreading northward into the central Plains ahead of this front. We could see an outbreak of severe storms along the front during the later afternoon and early evening hours as stronger southwesterly flow aloft moves into western Kansas. Chances for showers and thunderstorms will linger into Monday as the upper trough continues to move out into the Plains but we should be drying out by Monday night and Tuesday as the upper wave continues east. Temperatures in Monday-Wednesday time period will be fairly cool given the 850 millibar temperatures in the single digits. Temperatures should moderate through the remainder of the extended period as upper level heights build over the western and central U.S. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 1200 AM CDT FRI MAY 9 2014 VFR conditions will prevail at all TAF sites through early Friday evening. As for winds, surface high pressure in the Northern Plains will sink southward into western Kansas overnight resulting in light and variable winds across the area. A lee side trough of low pressure will develop across eastern Colorado early Friday morning turning winds southwesterly 10 to 20kt by mid day Friday. && .PRELIMINARY POINT TEMPS/POPS... DDC 48 82 55 81 / 0 0 10 20 GCK 47 81 50 72 / 0 0 10 10 EHA 50 85 50 77 / 0 0 0 10 LBL 48 86 52 80 / 0 0 10 10 HYS 48 80 52 69 / 0 0 10 20 P28 53 86 61 88 / 0 10 10 30 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJohnson SHORT TERM...Russell LONG TERM...Gerard AVIATION...JJohnson
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1141 PM CDT Thu May 8 2014 ...AVIATION UPDATE... .UPDATE... Issued at 1002 PM CDT THU MAY 8 2014 The cold front has started moving east once again and thunderstorm development has recommenced, likely due to increased low level convergence and possibly a weak wave lifting north along the KS/MO state line. Thinking is that instability has weakened from previous convection and cooling of the boundary layer. Because of this we have allowed the watch to expire thinking the chances for widespread severe weather will continue to diminish as the boundary layer cools. Latest radar data suggest there could be some small hail with the stronger updrafts, so we`ll have to continue monitoring storms for a little while longer. Latest water vapor imagery continues to show another shortwave now moving into southwest KS. This wave may help some scattered showers and thunderstorm activity to form late tonight over east central KS. Because of this have continued with some chance pops mainly south of I-70. UPDATE Issued at 634 PM CDT THU MAY 8 2014 Think the cold front will continue to make steady progress east, however outflow from recent convection seems to have masked the true front. The latest RAP and HRRR suggest the stronger convection could be east of the forecast area by 01Z and have trended the forecast in this direction. As the front makes clear progress east, will continue to clear out counties from the watch. Main hazard remains large hail, although available instability only around 1000 J/kg seems to be limiting the storms ability to maintain an updraft. Low level shear parameters do not look very supportive for much of a tornado threat. && .SHORT TERM...(Through Tonight) Issued at 252 PM CDT THU MAY 8 2014 The main focus for the short term is on the potential for thunderstorm development, with some strong to severe storms possible. Water vapor imagery showed the deep mid-level trough progressing eastward into the High Plains with a swath of dry air stretching across the western half of Kansas and the cloud cover gradually diminishing across eastern Kansas. The main surface low was situated over eastern Nebraska, with a secondary low developing over western Oklahoma near the Texas panhandle. As of 19z, the radar and surface obs showed the cold front stretching between these surface lows being located generally along a line from Seneca to Alma to Council Grove. Dewpoints ahead of this boundary where still in the low/mid 60s, with drier conditions settling in behind the boundary as dewpoints dropped into the upper 40s to upper 50s across north central Kansas. The cloud cover along with veering winds behind the front have limited afternoon heating with temperatures generally in the 70s. At 19z, radar showed a few showers and thunderstorms beginning to initiate along this boundary over far eastern/southeast Nebraska. Short-range models show this development continuing to spread southward along the boundary into northeast and eastern Kansas after 20z with more scattered storm development by the 22z-00z time frame, progressing eastward into Missouri during the evening hours. This region looks to be favorable for the development of strong to severe supercell thunderstorms as there is limited convective inhibition in place. MUCAPE is modest with upwards of 1000-2000 J/kg, and there is decent 0-6km bulk shear of 50-60kts. With the frontal passage, soundings show some veering of the low-level winds with 0-1km bulk shear potentially upwards of 15-20kts, so cannot rule out the potential for a few isolated tornadoes across far eastern Kansas. However, the main severe threat looks to be large hail with upwards of golfball size hail possible with the stronger storms. Could also see some damaging winds with this activity. These thunderstorms should initially be somewhat scattered in nature, and develop more into a line of storms by early this evening as the cold front progresses eastward, with this main thunderstorm activity diminishing by mid to late evening. However, additional shower and thunderstorm develop is possible overnight across east central Kansas as the secondary low tracks northeastward into southeast Kansas. Expect these storms to be elevated in nature and should exit east of the area Friday morning. Winds will continue to veer to the west and northwest behind the front tonight into Friday morning, with clearing skies across much of the northwestern half of the forecast area overnight. As a result, expect to see a spread in low temperatures tonight ranging from the middle 40s over north central Kansas to the middle 50s across east central Kansas due to the lingering shower and thunderstorm activity. .LONG TERM...(Friday through Thursday) Issued at 252 PM CDT THU MAY 8 2014 All indications are that the main PV anomaly/trough axis will exit the forecast area by around 15Z on Friday with a few lingering showers or even a thunderstorm possible through that time. Otherwise, expect downward motion and some dry advection to bring sunshine by afternoon. The post-frontal airmass is substantially cooler, but expect to mix up to 850 or even 800 hPa with sunshine and westerly winds, and still expect highs to climb into the 70s. Nearly zonal upper flow prevails into early Saturday with the front weakening and stalling over southern KS or northern OK. Should see dry conditions through Friday night and much of Saturday but expect the front to return north with warm moist advection Friday night into Saturday morning as surface low pressure develops from eastern Colorado into the OK panhandle. So have gone warmer with Friday night lows, and also a bit warmer on Saturday as cloud cover should be limited and the airmass rather warm. By Saturday afternoon, expect a negatively tilted short wave trough to eject across the Dakotas. This storm system will have a glancing impact on the local forecast area, but this bit of ascent will combine with moderate to strong instability expected by Saturday afternoon, along with a frontal boundary that will likely be lingering in the area or drifting back south across parts of Kansas. Expect the cap to be erased by mid to late afternoon, and the instability in conjunction with 30 to 50 kts of 0-6 km wind shear should result in scattered thunderstorms developing near the front. The most likely area seems to be near/south of I-70 at this time, and some of these storms would likely take on supercell characteristics with at least some potential for large hail. The wind potential will at least partially be tied to how warm temperatures get in the warm sector...warmer equating to greater damaging wind potential. Tornado potential seems on the low side given current forecast parameters given expectation for somewhat veered low level winds...but with a nearly stationary front in play, some small potential may exist. Expect a weak embedded short wave trough to perhaps enhance thunderstorm coverage near and even north of the front as the low level jet intensifies after sunset. This could allow the hail threat to persist north of the front through the overnight hours with elevated convection. On Sunday, expect a deep upper trough to begin to eject into the central Plains. The surface low is expected to deepen markedly over the OK panhandle while the surface front should remain across the local forecast area. One of the most significant uncertainties in the Sunday forecast regards the location of the front. The ECMWF is strongest/farthest north with the surface low and hence has the front extending across north central KS. The NAM...which can be flaky with details at the end of the forecast run...is stronger with the cold front progression and has the boundary along the boundary by 00Z Monday. The GFS is playing middle ground at this time. Another area of uncertainty lies in any stabilization that may occur with any overnight/early morning convection as we`ve seen with recent events. Wherever the boundary is located by Sunday afternoon, the warm sector south of the front should be characterized by strong to extreme instability and ample deep layer wind shear. Thunderstorms are likely to develop by mid afternoon along the front and become supercellular and severe. Low level winds again appear to be veered a bit but still with a fair amount of low level shear. All told, this appears to be an elevated chance for severe storms along and south of the frontal boundary...again focused near/south of I-70 for highest chances. The extent of storm severity will depend on several factors that can not currently be resolved but given magnitude of shear and instability the potential for widespread severe is evident. Showers and thunderstorms are expected to linger into Monday, with the end time depending on the speed of the upper trough which appears to be rather slow in its eastward progression. There are indications of lingering instability into the day on Monday in eastern KS but severe potential is questionable and quite low at this time. The upper low is showing a fair potential to slow and stall invof the western Great Lakes which would keep the local area in cool NW flow for several days with a fair amount of cloud cover. This long term forecast is rather uncertain though as even a minor eastward shift to the upper low would bring more frequent sunshine and temps would be quite a bit warmer. && .AVIATION...(For the 06Z TAFs through 06Z Friday Night) Issued at 1141 PM CDT THU MAY 8 2014 With dryer air moving in behind the front, VFR conditions should prevail. There is still a wave to the west that should move across the area bringing some mid level clouds overhead through sunrise. There could also be some -RA but most guidance is keeping any QPF south of the terminals so will not mention any precip at this time. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...Wolters SHORT TERM...Hennecke LONG TERM...Barjenbruch AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS JACKSON KY
205 AM EDT FRI MAY 9 2014 .UPDATE... ISSUED AT 205 AM EDT FRI MAY 9 2014 GRIDS AND FORECAST ARE IN FINE SHAPE EARLY THIS MORNING. ONLY MADE SOME MINOR TWEAKS TO MATCH UP WITH HOURLY TRENDS. LOOKING OVER LATEST FORECAST SOUNDINGS FOR THIS AFTERNOON...AND THINGS DO NOT LOOK REAL IMPRESSIVE. BELIEVE MODELS...NAM/GFS ARE OVERDOING SFC MOISTURE AGAIN AND CONSEQUENTLY SFC BASED INSTABILITY. INTERESTINGLY...GFS MODEL GUIDANCE IS ADVERTISING ONLY A 20-30 PERCENT CHANGE OF THUNDER. NAM MET MOS IS HIGHER...BUT ONLY DUE TO THE TYPICALLY HIGHER BIAS IN SFC DEW POINTS AND IS STILL ONLY SHOWING A 40 PERCENT CHANCE OF THUNDER. APPEARS THE DRIER RAP MAY HAVE A SLIGHTLY BETTER HANDLE ON THINGS. IN ADDITION...SOUNDINGS HAVE THAT FAMILIAR INVERTED V PROFILE TYPICALLY SEEN IN THE WESTERN CONUS. MAY DECIDE TO CUT BACK ON PROBABILITY OF THUNDER WITH NEXT UPDATE...FROM LIKELY TO CHANCE. HOWEVER...WITH DRIER LOWER LEVELS THIS ALSO MEANS THAT ANY SHOWERS THAT DEVELOP WILL TEND TO BE HIGH BASED AND PRODUCE GUSTY WINDS DUE TO THE ADDITIVE MOMENTUM OF EVAPORATIVE COOLING. BUT WILL EVALUATE/COLLABORATE WITH NEIGHBORS BEFORE MAKING ANY FINAL DECISIONS. UPDATE ISSUED AT 1055 PM EDT THU MAY 8 2014 DID A QUICK UPDATE TO FINE TUNE THE SKY COVER WEST TO EAST OVERNIGHT. ALSO TWEAKED THE T/TD GRIDS THROUGH THE EARLY OVERNIGHT BASED ON THE LATEST OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 730 PM EDT THU MAY 8 2014 23Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE HOLDING ON OVER THE SOUTHEAST PART OF THE NATION WHILE EAST KENTUCKY REMAINS IN THE BROAD WARM SECTOR OF A LARGE HIGH PLAINS LOW. WARM MID LEVEL TEMPERATURES CONTINUE TO CAP THE AREA PREVENTING ANY CONVECTION AND LIMITING THE LOWER CLOUDS TODAY. THIS HELPED SEND TEMPERATURES INTO RECORD AND NEAR RECORD TERRITORY AGAIN THIS AFTERNOON. SOME HIGH CLOUDS ARE NOW STARTING TO THICKEN UP OVER THE REGION IN RESPONSE TO THE PLAINS SYSTEM/S COLD FRONT MOVING EAST. DO NOT EXPECT THESE CLOUDS TO COMPLETELY COVER THE AREA BEFORE MUCH LATER TONIGHT...BUT THEY WILL STILL LIKELY IMPACT THE NATURE OF THE PERSISTENT RIDGE AND VALLEY TEMPERATURE SPLITS THAT WE HAVE BEEN SEEING THE PAST SEVERAL NIGHTS. WILL STILL FORECAST ONE...PARTICULARLY IN THE EAST...BUT TEMPER IT FOR MOST OF THE AREA AND FORECAST THE BEST AND FASTEST TEMPERATURE DECLINES EARLIER IN THE NIGHT. HAVE UPDATED THE GRIDS WITH THESE THOUGHTS IN MIND...AS WELL AS INCORPORATING THE LATEST OBS AND TRENDS FOR THE NEAR TERM. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 250 PM EDT THU MAY 8 2014 THE MODELS ACTUALLY HAVE QUITE A BIT OF DIFFERENCE IN THE TIMING OF THIS NEXT SYSTEM APPROACHING THE AREA TOMORROW. BY 8 PM ON FRIDAY...A COLD FRONT WILL EXTEND ACROSS WESTERN MICHIGAN TO SOUTHEASTERN MISSOURI AND THE INTO THE TEXAS MIDLANDS. THERE WILL BE SHOWERS AND THUNDERSTORMS FIRING UP AHEAD OF THIS SYSTEM ON FRIDAY. THIS IS WHERE THE MODELS DIVERGE AS TO THE EXTENT AND TIMING OF THE PREFRONTAL STORMS IN THE WARM SECTOR. THE TIME OF ARRIVAL FOR THE LEADING EDGE IN THE MODELS VARY FROM 5 PM FRIDAY TO 10 PM ON FRIDAY. THE MODEL CONSENSUS WOULD FAVOR THE LATER ARRIVAL TIME. THE BEST CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE LATE FRIDAY NIGHT AND INTO SATURDAY. THE FRONT SHOULD BE MOVING INTO EASTERN KENTUCKY ON SATURDAY MORNING. THE THREAT OF ANY SEVERE THUNDERSTORMS WITH THE SYSTEM IS VERY LOW AND ONLY GARDEN VARIETY STORMS ARE EXPECTED WITH THIS SYSTEM. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 334 PM EDT THU MAY 8 2014 THE MODELS WERE NOT IN THE BEST OF AGREEMENT THIS GO ROUND...SO THE EXTENDED PORTION OF THE FORECAST MADE WITH LOW CONFIDENCE. THE OVERALL PATTERN SUGGESTS A THAT INITIALLY A FAIRLY WELL DEFINED COLD FRONT WILL MOVE SLOWLY ACROSS THE AREA SATURDAY AND SATURDAY NIGHT. WITH AMPLE MOISTURE AND INSTABILITY IN PLACE...THE START OF THE PERIOD DOES LOOK FAIRLY GOOD IN TERMS OF THE VARIOUS MODEL SOLUTIONS AND THEIR AGREEMENT THERE. THEREFORE...DECIDED TO CONTINUE WITH THE LIKELY PRECIPITATION PROBABILITIES TO END THE WEEKEND ACROSS THE AREA. AFTER THAT...HOWEVER...THE MODELS GO QUITE A BIT OUT OF AGREEMENT. THE GFS IS MUCH FASTER THAN THE ECMWF WITH THE PROGRESSION OF A LARGE SCALE UPPER TROUGH THROUGHOUT THE WORK WEEK...AND A SERIES OF FRONTAL BOUNDARIES THAT ARE PROGGED TO AFFECT THE AREA. WITH THE AMOUNT OF UNCERTAINTY WE ARE SEEING...IT SEEMED PLAUSIBLE TO ADJUST THE LATEST MODEL DATA INGEST VERY LITTLE AND KEEP IN LINE WITH OUR NEIGHBORS. IT LOOKS LIKE ISENTROPIC LIFT ASSOCIATED WITH A WARM FRONT WILL BE THE CULPRIT FOR PRECIPITATION THROUGHOUT THE PERIOD WHEN A COLD FRONT LOOMS TO OUR WEST IN THE WARM SECTOR OF AN APPROACHING AREA OF LOW PRESSURE. AT THIS TIME...THE FORECAST WILL CALL FOR PERIODS OF SHOWERS AND THUNDERSTORMS THROUGHOUT THE WEEK...WITH SOME BREAKS FROM THE PRECIP HERE AND THERE AS THE WARM MIGRATES NORTH OF THE OHIO RIVER. TEMPERATURES DURING THE PERIOD SHOULD BE QUITE WARM...WITH DAILY HIGHS IN THE 70S AND 80S THROUGH TUESDAY. COOLER TEMPERATURES COULD BE ON TAP TO END THE WEEK...IF A SECOND AREA OF LOW PRESSURE IN FACT DOES IMPACT THE AREA. TEMPERATURES NEXT WEDNESDAY AND THURSDAY MAY ONLY MAKE IT INTO THE 60S ACROSS THE BOARD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 205 AM EDT FRI MAY 9 2014 LOOKING AT VFR CONDITIONS THROUGH THE ENTIRE FORECAST PERIOD. MAIN CHALLENGE TO THE AVIATION FORECAST WILL BE THE POTENTIAL FOR THUNDERSTORMS LATER TODAY. THINGS DO NOT LOOK REAL IMPRESSIVE BASED ON LATEST FORECAST SOUNDINGS. BELIEVE MODELS...NAM/GFS ARE OVERDOING SFC MOISTURE AGAIN AND CONSEQUENTLY SFC BASED INSTABILITY. SOUNDINGS ALSO HAVE THE FAMILIAR INVERTED V PROFILE TYPICALLY SEEN IN THE WESTERN CONUS. THOUGHTS ARE THAT WE MAY CUT BACK ON PROBABILITY OF THUNDER...FROM LIKELY TO CHANCE. HOWEVER...WITH DIRER LOWER LEVELS THIS ALSO MEANS THAT ANY SHOWERS THAT DEVELOP WILL TEND TO BE HIGH BASED AND PRODUCE GUSTY WINDS DUE TO THE ADDITIVE MOMENTUM OF EVAPORATIVE COOLING OF RAINFALL. LIGHT AND VARIABLE WILL INCREASE FROM THE SOUTH...SOUTHWEST AT 10 TO 15 KTS BY MIDDAY FRIDAY. A FEW GUSTS TO 20 KTS WILL BE POSSIBLE LATE IN THE DAY FRIDAY. AGAIN... WINDS COULD BE QUITE VARIABLE AND GUSTY AROUND ANY SHOWERS AND THUNDERSTORMS THAT MAY DEVELOP. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...JJ LONG TERM...AR AVIATION...RAY
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1122 PM CDT Thu May 8 2014 .UPDATE... Issued at 1122 PM CDT THU MAY 8 2014 Update for 6z aviation only. UPDATE Issued at 845 PM CDT THU MAY 8 2014 A north to south oriented line of thunderstorms with trailing stratiform rain is approaching the Mississippi River and will continue to move north northeast into southern Illinois mainly to the west of I-57 through the remainder of the evening. It looks like western portions of southeast Missouri will be drying out pretty soon, and they may have a few hours before the next round arrives midnight or a bit later. LAPS soundings indicate a weakening cap and the RAP has LI`s of -2 to -3 over southern Illinois. See no reason why they will not continue through much of southern Illinois with modest intensity this evening. Not sure just how far east they will get, but the RAP tries hard to confine the precipitation to Missouri and Illinois through midnight. Of course, as the upper trough pushes closer to the area overnight, another round of widespread showers and thunderstorms is expected to overspread most of the area by daybreak Friday morning. Tried to account for the aforementioned trends in the hourly pop/wx grids, but made few other changes with this update. The Lake Wind Advisory died a natural death at 01Z. UPDATE Issued at 610 PM CDT THU MAY 8 2014 UPDATE FOR AVIATION ONLY. && .SHORT TERM...(Tonight through Saturday night) Issued at 304 PM CDT THU MAY 8 2014 Focus in the short term continues to be on convective chances. Band of convection central/sw MO into west AR will track slowly east late this afternoon and evening. Will have best chance PoPs west 1/2 before midnight shifting slowly east overnight. Really not all that concerned about severe wx over our SEMO counties at this time given marginal lapse rates modest instability. Convective chances will shift east Friday morning. It may linger from SW IN into the Pennyrile through early afternoon, where temps may be held down a couple of degrees. Otherwise, the atmosphere should have some time to recover heading west, ahead of an approaching, stalling front. Convection should take shape in this area and eventually focus SRN IL into SE MO late in the day in some form or fashion then head east through the evening. Mid and upper level winds are relatively impressive, not so much blyr- 700mb. Storms with decent mid level rotation, with steepening low level lapse rates may yield wind and hailers, best chances west/southwest part of the CWFA. Chances should diminish from west to east after midnight Friday night. May see a lull Saturday, then another chance moving in from the west overnight Saturday night, potentially an MCS. Slightly better chances north than south. .LONG TERM...(Sunday through Thursday) Issued at 304 PM CDT THU MAY 8 2014 The main weather story during the long term will be a strong cold front that will sweep across our region early next week. This front will be accompanied by a period of rain and thunderstorms. The front will bring a noticeable cooling of temperatures from above normal to below normal. As far as the daily details... On Sunday...a reservoir of warm...moist and very unstable air will cover a large part of the central states including our region. It is likely that one or more convective systems will develop over the Plains and then propagate eastward through this unstable air mass...fed by a moderately strong low level jet. Since there is little skill at forecasting these systems in the long range period...the forecast will include a generic chance pop. High temps will remain quite warm...basically in line with gfs/ecmwf mos. On Monday...the high amplitude 500 mb trough and associated cold front will draw closer. The genesis region of convective systems will remain to our west. Will continue with a warm and humid forecast along with chance pops. There remains unusually wide divergence among the models concerning the timing of the frontal system Monday night through Tuesday night. Both the gfs and ecmwf have trended slower compared to this time Wednesday. The 12z gfs takes the front across our region on Monday night...while the ecmwf has it coming through Tuesday night. The highest pops will be on Tuesday...mainly in the likely category across our region. Will introduce chance pops for Wednesday based on the slower timing of the system. However...the bulk of the precip should be over by then. The model 850 temps have trended cooler for Wednesday into Thursday by several degrees. Based on model 850 mb temps from plus 1 to plus 4...highs will only be in the 60s even with plenty of sun. Forecast temps will be trended lower for Wed into Thurs. && .AVIATION... Issued at 1122 PM CDT THU MAY 8 2014 Kcgi is expected to break out of the precip between 6z and 9z. After that rain will start to move in again. However raised cigs prevailing and tempo in light of the vfr cigs in tsra earlier. Slowly bring them into MVFR territory between 9z and 18z. Then only a prob group after that. Also maintained LLWS overnight as fcst sounding indicate 40kt at 2k feet. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...KH AVIATION...KH
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1153 PM CDT THU MAY 8 2014 .AVIATION... A LINE OF STRONG CONVECTION WILL CONTINUE TO MOVE EAST ACROSS PORTIONS THE FORECAST AREA EARLY THIS MORNING. EXPECT MODERATE TO ISOLATED SEVERE TURBULENCE WITH THIS ACTIVITY AS WELL AS PERIODS OF IFR CIGS AND VSBYS DUE TO HEAVY RAINFALL. FOLLOWING THE LINE...CIGS MAY CLEAR BRIEFLY ACROSS EAST TEXAS INTO SOUTHEAST OKLAHOMA AND SOUTHWEST ARKANSAS. HOWEVER...AFTER 09Z...EXPECT IFR FLIGHT CONDITIONS TO RETURN IN SOME LOCATIONS DUE TO FOG AND/OR LOW CIGS. ACROSS LOUISIANA...CIGS WILL REMAIN MOSTLY MVFR WITH OCCASIONAL VSBYS BETWEEN 2 AND 5 MILES IN RAIN AND FOG. CONDITIONS WILL IMPROVE BETWEEN 15Z AND 17Z FRIDAY TO VFR MOST LOCATIONS. EXCEPT FOR WEST TO NORTHWEST WIND GUST TO AROUND 25 KTS IN AND AROUND CONVECTION...SURFACE WIND TO REMAIN SOUTH 5 TO 10 KTS TONIGHT. AFTER 14Z FRIDAY...EXPECT SOUTH TO SOUTHWEST WIND 10 TO 15 KTS. /14/ && .PREV DISCUSSION... /ISSUED 946 PM CDT THU MAY 8 2014/ DISCUSSION... MOSAIC RADAR ANALYSIS SHOWING A RATHER LARGE LINE OF CONVECTION EXTENDING FROM SOUTH CENTRAL ARKANSAS THROUGH EXTREME NORTHWEST LOUISIANA AND NORTHEAST TEXAS. THIS ACTIVITY DEVELOPING WELL AHEAD OF THE SHORTWAVE TROUGH WHICH IS CURRENT ACROSS THE TX/OK PNHDL INTO THE SOUTHERN AND CENTRAL PLAINS. HRRR HAS A GOOD HANDLE ON THIS CONVECTION CONTINUING TO PUSH SOUTH AND EAST THROUGH THE NIGHT WITH RAINFALL RATES NEAR 1.5 INCHES PER HOUR ALONG THE LEADING EDGE OF THE CONVECTION. HAVE UPDATED THE FORECAST TO GO WITH CATEGORICAL POPS ACROSS THE NORTHWEST HALF FOR THE REMAINDER OF THE EVENING AND THEN ACROSS THE EASTERN HALF AFTER MIDNIGHT. ALSO ADDED THE LOCALLY HEAVY RAINFALL MODIFIER GIVEN THE RAINFALL RATES AND WHAT HAS ALREADY OCCURRED. CONCERNING TEMPERATURES...OUR NORTHWEST ZONES ARE ALREADY A DEGREE OR TWO BELOW FORECAST MINS SO LOWERED MINS BUT THESE TEMPERATURES MAY RECOVER SLIGHTLY AFTER THE CONVECTION ENDS. ALSO ADJUSTED SKY/WIND AND DEWPOINT GRIDS BASED ON CURRENT TRENDS. UPDATE ALREADY SENT...13. && .PRELIMINARY POINT TEMPS/POPS... SHV 68 84 67 87 68 / 80 40 20 20 20 MLU 71 82 66 86 67 / 80 50 30 20 20 DEQ 64 84 61 85 66 / 80 50 20 20 20 TXK 66 83 66 86 67 / 80 50 40 20 20 ELD 66 83 65 86 66 / 80 50 40 20 20 TYR 66 88 66 88 70 / 80 20 20 20 10 GGG 68 87 66 87 70 / 80 30 20 20 10 LFK 71 89 68 88 70 / 80 30 20 20 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
501 AM EDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 444 AM EDT FRI MAY 9 2014 THE UPPER TROUGH THAT HAS BEEN CONTROLLING OUR WEATHER FOR THE LAST COUPLE OF DAYS IS CURRENTLY MOVING NORTHEAST THROUGH THE CENTRAL PLAINS. MOISTURE LADEN AIR STREAMING NORTHEAST AHEAD OF THIS TROUGH CAN BE SEEN ON WV IMAGERY EARLY THIS MORNING...WHICH IS HELPING TO FUEL SHOWERS AND ISOLATED THUNDERSTORMS FROM WESTERN LAKE SUPERIOR THROUGH PORTIONS OF UPPER MICHIGAN...AND SOUTHEAST TO EASTERN WISCONSIN. AT THE SURFACE...A 998MB LOW IS LOCATED JUST SOUTHWEST OF DULUTH AND A WARM FRONT STRETCHES EAST ALONG THE U.P. AND WISCONSIN BORDER. SHORTWAVES EMBEDDED WITHIN THE WARM MOIST SOUTHWESTERLY FLOW CONTINUES TO PRODUCE AREAS OF THUNDERSTORMS OVER THE WESTERN HALF OF THE GREAT LAKES REGION AND EXPECT THAT TO CONTINUE FOR AREAS WITHIN THE WARM/MOIST AIRMASS. AS THE LOW LIFTS NORTHEAST TODAY...THE COLD FRONT (CURRENTLY STRETCHING SOUTH FROM SOUTHEAST MINNESOTA THROUGH NORTHERN MISSOURI) WILL SWEEP NORTHEAST ACROSS THE UPPER GREAT LAKES REGION. WITH THE SHOWER/THUNDERSTORM COVERAGE STARTING TO BECOME MORE SCATTERED/ISOLATED...WILL FOLLOW THAT IDEA FOR POPS AHEAD OF THE COLD FRONT. ALREADY STARTING TO SEE THE AFFECT OF THE DRYING ALOFT OVER NORTHWEST WISCONSIN AND EXPECT THE LAST AREAS OF SHOWERS FOR THIS MORNING TO PUSH THROUGH WESTERN UPPER MICHIGAN OVER THE NEXT COUPLE OF HOURS. AS THAT DRYING SHIFTS EAST THIS MORNING...WILL DIMINISH POPS FROM WEST TO EAST DURING THE MORNING HOURS. WITH THERE STILL BEING SOME ISOLATED THUNDER ON THE BACK EDGE OF THE PRECIPITATION (EVEN THOUGH RAP ANALYSIS OF MUCAPE AND MID-LEVEL LAPSE RATE VALUES ARE VERY WEAK)...HAVE EXTENDED THE SLIGHT CHANCE OF THUNDER A LITTLE LONGER OVER THE EAST THIS MORNING TO COINCIDE WITH THE AXIS OF MOISTURE AND LATEST THUNDER AREAS. BEHIND THE COLD FRONT...MAY SEE A FEW PEAKS OF SUNSHINE OVER THE CENTRAL/EAST (WHERE FOG ISN/T OCCURRING) AS THIS MID LEVEL DRY SLOT MOVES THROUGH AND BEFORE THE NEXT WAVE OF LOW LEVEL MOISTURE AND PRECIPITATION (CURRENTLY IN THE EASTERN DAKOTAS AND WESTERN MINNESOTA) MOVES OVER THE AREA. WILL CONTINUE THE IDEA SHOWN IN THE PREVIOUS FORECAST OF ISOLATED TO SCATTERED SHOWERS MOVING OVER THE WEST OR NORTHWEST HALF OF THE CWA LATER THIS AFTERNOON AND CONTINUING THROUGH A GOOD PORTION OF THE NIGHT TONIGHT (ESPECIALLY THE KEWEENAW TONIGHT). QPF AMOUNTS WILL BE MUCH LIGHTER THAN SEEN OVER THE LAST COUPLE DAYS AND MAINLY BETWEEN A TRACE AND A COUPLE TENTHS. IN ADDITION...IT WILL BECOME BREEZY BEHIND THE COLD FRONT...WITH BUFKIT SOUNDINGS INDICATING GUSTS AROUND 25KTS OVER MUCH MUCH OF UPPER MICHIGAN TODAY. WITH THE COLD AIR ADVECTION IN PLACE THROUGH MUCH OF TONIGHT...THOSE GUSTS WILL LIKELY KEEP UP AS WINDS SHIFT TO THE WEST THROUGH THE NIGHT. WHILE THE KEWEENAW MAY BE PROTECTED SLIGHTLY TODAY...THE WINDS SHOULD REALLY KICK IN TONIGHT AS IT IS CLOSEST TO THE TIGHTEST PRESSURE GRADIENT WITH THE DEPARTING LOW AND RESULTING STRONGER WINDS JUST ABOVE THE SURFACE. EXPECT THERE TO BE A PERIOD THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS WHERE GUSTS IN THE KEWEENAW WILL BE BETWEEN 30-35KTS. FINALLY FOR TEMPERATURES...VALUES THIS MORNING HAVE BEEN CONSISTENT IN THE 50S OVER THE INTERIOR LOCATIONS...ALTHOUGH LOCATIONS NEAR THE COOLING OF THE GREAT LAKES HAVE BEEN BOUNCING UP AND DOWN DEPENDING ON THE WIND DIRECTION. WITH THE WARM START AND THE WARM FRONT PUSHING NORTHEAST THROUGH MUCH OF UPPER MICHIGAN TODAY...SHOULD SEE TEMPERATURES RISE INTO THE MID-UPPER 60S OVER THE CENTRAL/EASTERN CWA AND WHERE SOME SUNSHINE OCCURS WILL PROBABLY SEE SOME SITES HITTING THE 70 DEGREE MARK. COLDER AIR ARRIVING BEHIND THE COLD FRONT WILL LEAD TO FALLING TEMPS OVER THE WEST IN THE AFTERNOON AND THE REST OF THE AREA TOWARDS EVENING. THE CLOUD COVER TONIGHT WILL KEEP TEMPS A LITTLE ABOVE NORMAL AND HAVE LOWS IN THE LOWER 40S. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 459 AM EDT FRI MAY 9 2014 PATTERN EVOLUTION DURING THE LONG TERM WILL BRING A RETURN OF A BUILDING RIDGE ALONG/NEAR THE W COAST OF NAMERICA THIS WEEKEND THRU THE FIRST HALF OF NEXT WEEK (POSITIVE ANOMALIES REACH THEIR MAX WED). THIS WILL FORCE A FAIRLY DEEP TROF FOR MID MAY TO AMPLIFY SOUTHWARD INTO THE CNTRL CONUS DURING THE EARLY PART OF NEXT WEEK WITH SLOW EASTWARD PROGRESSION THEREAFTER. THE BUILDING RIDGE WILL FORCE THE UPPER LOW/ENERGY NOW IN THE GULF OF ALASKA TO DIVE SE TOWARD THE SRN ROCKIES. AS THE ENERGY THEN LIFTS NE...ANOTHER ACTIVE LOW PRES SYSTEM WILL MOVE NE INTO THE UPPER MISSISSIPPI VALLEY ON A TRACK SIMILAR TO THE SYSTEM CURRENTLY AFFECTING THE MISSISSIPPI VALLEY/WRN GREAT LAKES. SO...AFTER A PERIOD OF DRY WEATHER EARLY IN THE WEEKEND...POTENTIAL OF SHRA WILL RETURN...PERHAPS AS EARLY AS LATE SAT NIGHT/SUN MORNING. DECENT PCPN AMOUNTS MAY THEN BE IN THE OFFING FOR MON/MON NIGHT AS LOW PRES LIFTS INTO THE UPPER MISSISSIPPI VALLEY. ONCE THE UPPER TROF REACHES THE WRN GREAT LAKES...THERE MAY BE A DAY OR 2 OF LIGHT SHOWERY PCPN AT TIMES IN THE MID WEEK PERIOD (PERHAPS EVEN A LITTLE SNOW MIXED IN). AS FOR TEMPS...READINGS OVER THE WEEKEND SHOULD BE CLOSE TO NORMAL... THOUGH IT WILL OBVIOUSLY BE COOL WHERE WINDS ARE ONSHORE NEAR THE GREAT LAKES. TEMPS WILL BEGIN TO TAKE A DOWNWARD TURN MON/TUE WITH THE EARLY WEEK LOW PRES SYSTEM...AND TEMPS WED/THU WILL LIKELY BE QUITE CHILLY/WELL BLO NORMAL FOR MID MAY AS UPPER TROF DRIFTS ACROSS THE AREA (850MB TEMPS FALL TO PERHAPS AS LOW AS -4 TO -6C). FARTHER DOWN THE ROAD...PATTERN WILL PROBABALY CONTINUE TO LEAN TOWARD MAINTAINING OVERALL BLO NORMAL TEMPS OUT TO 10-14 DAYS. BEGINNING SAT...LOW CLOUDS AND POSSIBLY SOME -SHRA/SPRINKLES/-DZ WILL LINGER EARLY OVER THE E. OTHERWISE...EXPECT ABUNDANT SUNSHINE OVER THE W TO SPREAD TO THE ERN FCST AREA BY AFTN AS FCST SOUNDINGS SHOW A DEEP DRY AIR MASS SPREADING OVER THE AREA. DRY AIR MASS WILL ALLOW FOR DEEP MIXING. MIXING UPWARDS OF 750MB ON FCST SOUNDINGS YIELDS MAX TEMPS INTO THE MID TO PERHAPS UPPER 60S IN THE INTERIOR. TEMPS WILL BE COOLEST ALONG LAKE SUPERIOR IN LOCATIONS WHERE WESTERLY WINDS HAVE AN OVERLAKE COMPONENT. LAKE BREEZE MAY DEVELOP NEAR LAKE MICHIGAN IN THE LATTER PART OF THE AFTN. WITH THE DEEP DRY AIR MASS...RH WILL LIKELY TUMBLE TO AS LOW AS AROUND 20PCT IN THE INTERIOR...IN PARTICULAR TOWARD THE WI BORDER. OUT AHEAD OF THE MAIN SYSTEM DIVING TOWARD THE SRN ROCKIES...A LEAD SHORTWAVE WILL SHIFT FROM THE WRN PLAINS SAT MORNING TO THE UPPER LAKES SUN MORNING. GIVEN THAT THE SHORTWAVE WILL BE HEADING INTO THE LARGE SCALE BUILDING UPPER RIDGE DOWNSTREAM OF THE MAIN TROF AMPLIFYING OVER THE ROCKIES...PCPN ASSOCIATED WITH SHORTWAVE WILL LIKELY BE DIMINISHING AS IT MOVES INTO THE UPPER LAKES. ANTECEDENT VERY DRY AIR MASS WILL FURTHER AID THE DIMINISHING OF PCPN SPREADING INTO THE AREA LATE SAT NIGHT/SUN MORNING. QUESTION WILL BE HOW FAST DOES THE PCPN DECAY. AT THIS POINT...IT APPEARS THE GFS IS MUCH TOO AGGRESSIVE WITH WIDESPREAD PCPN IT MOVES ACROSS THE FCST AREA WITH AS MUCH AS 0.25-0.40 INCHES OVER ROUGHLY THE NW HALF OF UPPER MI. OTHER GUIDANCE IS DRIER WITH PCPN DRYING UP AS IT MOVES INTO/ACROSS THE THE FCST AREA. THE NAM IN PARTICULAR HAS ALMOST NO PCPN REACHING UPPER MI. WILL FAVOR THE DRIER SOLUTIONS GIVEN BUILDING UPPER RIDGE AND ANTECEDENT DRY AIR MASS. ONLY CHC POPS WILL BE UTILIZED LATE SAT NIGHT THRU SUN MORNING WITH POPS LOWEST OVER THE NE. CLOUD COVER/PCPN WILL HAVE AN IMPACT ON HIGH TEMPS SUN. IN FAVORING THE DRIER SOLUTIONS...WILL ALSO LEAN TOWARD THE WARMER GUIDANCE FOR HIGHS SUN. AWAY FROM LAKE MODERATION...TEMPS SHOULD REACH WELL INTO THE 60S TO NEAR 70F. MAIN SHORTWAVE MOVES OUT ACROSS THE SRN PLAINS MON MORNING AND LIFTS INTO THE UPPER MISSISSIPPI VALLEY MON NIGHT/TUE ALONG WITH ASSOCIATED SFC LOW PRES. THERE IS CONSIDERABLE MODEL SPREAD ON TIMING SYSTEM WITH SOME HINTS OF A SLOWER TREND DEVELOPING. THE UKMET IS SLOWEST...SHOWING LOW PRES ONLY IN WCNTRL WI AT 00Z WED. NEXT IS THE GEM...SWINGING FROPA THRU UPPER MI TUE AFTN-TUE NIGHT. THE ECMWF BRINGS FRONT THRU MON NIGHT/TUE MORNING WHILE THE GFS IS QUICKEST...PUSHING FRONT ACROSS THE AREA MON EVENING. CONSENSUS OF RECENT RUNS WILL BE UTILIZED GIVEN SPREAD. AT THIS TIME...BEST CHANCE OF SHRA SOME TSRA APPEARS TO BE MON/MON NIGHT...BUT IF SLOWER TREND GAINS MOMENTUM...TIMING WILL NEED TO BE PUSHED BACK A BIT. AS UPPER TROF DRIFTS ACROSS THE WRN LAKES WED/THU...THERMAL TROF WITH 850MB TEMPS IN THE -2 TO -6C RANGE WILL YIELD ABUNDANT CLOUD COVER...ESPECIALLY DURING THE DAYLIGHT HRS. HIGH SUN ANGLE (ONLY 5 1/2 WEEKS TO THE SUMMER SOLSTICE DURING THE MIDDLE OF NEXT WEEK) WILL PROBABLY SUPPORT AT LEAST SCT -SHRA ACTIVITY...PEAKING IN THE AFTN HRS. GIVEN THE COLD TEMPS IN THE COLUMN...MAY SEE SOME GRAUPLE...AND PERHAPS EVEN SOME SNOWFLAKES IF PCPN LINGERS INTO THE NIGHT. IF WED OR THU ENDS UP MAINLY CLOUDY WITH NMRS -SRHA...HIGH TEMPS MAY STRUGGLE TO GET INTO THE 50S INLAND WHILE DAYTIME TEMPS MAY HOLD TO THE MID 30S TO MID 40S NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 128 AM EDT FRI MAY 9 2014 SHOWERS AND SCT TSRA WILL LIFT TO THE NE THROUGH UPPER MICHIGAN OVERNIGHT. AS A RESULT...LOW LEVEL MOISTENING FROM THE RAIN AND S TO SE FLOW WILL KEEP OR DROP CIGS INTO THE IFR/LIFR RANGE TONIGHT. CONDITIONS WILL IMPROVE FRI MORNING AS WINDS BECOME SW AND GREATER DRYING/MIXING MOVES IN. A BRIEF PERIOD OF VFR CONDITIONS MAY DEVELOP BY AFTERNOON BUT LOWER MVFR CIGS ARE EXPECTED TO REDEVELOP OVER THE WEST AS ADDITIONAL MOISTURE WRAPS AROUND THE DEPARTING LOW PRESSURE SYSTEM. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 422 AM EDT FRI MAY 9 2014 A LOW PRESSURE SYSTEM NEAR DULUTH EARLY THIS MORNING WILL SLIDE NORTHEAST INTO ONTARIO TODAY. AS THIS OCCURS...WINDS WILL SHIFT AROUND TO THE SOUTHWESTERLY DIRECTION TODAY AND THEN TO THE WEST TONIGHT. EXPECT THE WINDS TO INCREASE FROM WEST TO EAST TODAY AND GENERALLY TO 25KTS TONIGHT...ALTHOUGH THERE COULD BE SOME GUSTS TO 30KTS OVER THE CENTRAL LAKE. THESE STRONGER WINDS...COMBINED WITH GRADUALLY DRYING LOWER LEVELS SHOULD LEAD TO A DIMINISHMENT OF THE DENSE FOG OVER LAKE SUPERIOR FROM SOUTHWEST TO NORTHEAST TODAY. OPTED TO EXTENDED THE DENSE FOG ADVISORY FOR LAKE SUPERIOR INTO THE AFTERNOON HOURS TO BETTER MATCH UP WITH THE INCREASING WINDS AND DRIER AIR. A HIGH PRESSURE RIDGE WILL THEN SLIDE OVER THE AREA ON SATURDAY AND LEAD TO WINDS FALLING BELOW 15KTS SATURDAY NIGHT. THESE LIGHT WINDS WILL REMAIN THROUGH SUNDAY EVENING. A LOW PRESSURE SYSTEM MOVING TOWARDS THE UPPER GREAT LAKES REGION FROM THE CENTRAL PLAINS ON SUNDAY NIGHT WILL LEAD TO INCREASING EASTERLY WINDS (TO 25KTS BY MONDAY EVENING). THEN AS THE LOW SHIFTS NORTHEAST INTO ONTARIO ON TUESDAY...WINDS WILL SHIFT TO THE SOUTHWEST AND STAY BELOW 20KTS. && .HYDROLOGY... ISSUED AT 456 AM EDT FRI MAY 9 2014 THE RAIN SHOWERS AND THUNDERSTORMS PRODUCING HEAVY RAIN HAVE NEARLY DEPARTED UPPER MICHIGAN EARLY THIS MORNING. BUT THEY HAVE LEFT RISING RIVER LEVELS IN THEIR WAKE...ESPECIALLY OVER WESTERN UPPER MICHIGAN WHERE THE HEAVIEST RAIN HAS FALLEN. THE KEWEENAW PENINSULA HAS SEEN AROUND 0.75 INCHES OVERNIGHT IN ADDITION TO THE INCH OF RAIN THAT FELL LAST NIGHT. THIS AS LED TO ANOTHER RISE OF THE TRAP ROCK RIVER OVER THE LAST COUPLE OF HOURS. IT HAS LEVELED OUT SOMEWHAT OVER THE LAST HOUR...BUT WITH A COUPLE HOURS LEFT OF RAIN AND SNOW MELT CONTINUING WOULD EXPECT A LITTLE MORE RISE THIS MORNING. IT DID BRIEFLY REACH 10.15FT...WHICH PUTS THE CURRENT CREST AT THE 4TH HIGHEST ON RECORD. WARM TEMPERATURES TODAY WILL CONTINUE THE MELTING FROM A FEW INCHES OF SNOW WATER EQUIVALENT SHOWN FROM NOHRSC MODEL FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /WARMER FCST TEMPS FOR THE REST OF THIS WEEK/ IMPACT DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND...BUT IT WILL KEEP THE RIVER LEVELS HIGH INTO EARLY NEXT WEEK. IN ADDITION...WIDESPREAD RAIN IS EXPECTED AGAIN ON MONDAY AND THE CURRENT FORECAST CALLS FOR AROUND A HALF AN INCH OF ACCUMULATION. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...ROLFSON AVIATION...JLB MARINE...SRF HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 AM EDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 444 AM EDT FRI MAY 9 2014 THE UPPER TROUGH THAT HAS BEEN CONTROLLING OUR WEATHER FOR THE LAST COUPLE OF DAYS IS CURRENTLY MOVING NORTHEAST THROUGH THE CENTRAL PLAINS. MOISTURE LADEN AIR STREAMING NORTHEAST AHEAD OF THIS TROUGH CAN BE SEEN ON WV IMAGERY EARLY THIS MORNING...WHICH IS HELPING TO FUEL SHOWERS AND ISOLATED THUNDERSTORMS FROM WESTERN LAKE SUPERIOR THROUGH PORTIONS OF UPPER MICHIGAN...AND SOUTHEAST TO EASTERN WISCONSIN. AT THE SURFACE...A 998MB LOW IS LOCATED JUST SOUTHWEST OF DULUTH AND A WARM FRONT STRETCHES EAST ALONG THE U.P. AND WISCONSIN BORDER. SHORTWAVES EMBEDDED WITHIN THE WARM MOIST SOUTHWESTERLY FLOW CONTINUES TO PRODUCE AREAS OF THUNDERSTORMS OVER THE WESTERN HALF OF THE GREAT LAKES REGION AND EXPECT THAT TO CONTINUE FOR AREAS WITHIN THE WARM/MOIST AIRMASS. AS THE LOW LIFTS NORTHEAST TODAY...THE COLD FRONT (CURRENTLY STRETCHING SOUTH FROM SOUTHEAST MINNESOTA THROUGH NORTHERN MISSOURI) WILL SWEEP NORTHEAST ACROSS THE UPPER GREAT LAKES REGION. WITH THE SHOWER/THUNDERSTORM COVERAGE STARTING TO BECOME MORE SCATTERED/ISOLATED...WILL FOLLOW THAT IDEA FOR POPS AHEAD OF THE COLD FRONT. ALREADY STARTING TO SEE THE AFFECT OF THE DRYING ALOFT OVER NORTHWEST WISCONSIN AND EXPECT THE LAST AREAS OF SHOWERS FOR THIS MORNING TO PUSH THROUGH WESTERN UPPER MICHIGAN OVER THE NEXT COUPLE OF HOURS. AS THAT DRYING SHIFTS EAST THIS MORNING...WILL DIMINISH POPS FROM WEST TO EAST DURING THE MORNING HOURS. WITH THERE STILL BEING SOME ISOLATED THUNDER ON THE BACK EDGE OF THE PRECIPITATION (EVEN THOUGH RAP ANALYSIS OF MUCAPE AND MID-LEVEL LAPSE RATE VALUES ARE VERY WEAK)...HAVE EXTENDED THE SLIGHT CHANCE OF THUNDER A LITTLE LONGER OVER THE EAST THIS MORNING TO COINCIDE WITH THE AXIS OF MOISTURE AND LATEST THUNDER AREAS. BEHIND THE COLD FRONT...MAY SEE A FEW PEAKS OF SUNSHINE OVER THE CENTRAL/EAST (WHERE FOG ISN/T OCCURRING) AS THIS MID LEVEL DRY SLOT MOVES THROUGH AND BEFORE THE NEXT WAVE OF LOW LEVEL MOISTURE AND PRECIPITATION (CURRENTLY IN THE EASTERN DAKOTAS AND WESTERN MINNESOTA) MOVES OVER THE AREA. WILL CONTINUE THE IDEA SHOWN IN THE PREVIOUS FORECAST OF ISOLATED TO SCATTERED SHOWERS MOVING OVER THE WEST OR NORTHWEST HALF OF THE CWA LATER THIS AFTERNOON AND CONTINUING THROUGH A GOOD PORTION OF THE NIGHT TONIGHT (ESPECIALLY THE KEWEENAW TONIGHT). QPF AMOUNTS WILL BE MUCH LIGHTER THAN SEEN OVER THE LAST COUPLE DAYS AND MAINLY BETWEEN A TRACE AND A COUPLE TENTHS. IN ADDITION...IT WILL BECOME BREEZY BEHIND THE COLD FRONT...WITH BUFKIT SOUNDINGS INDICATING GUSTS AROUND 25KTS OVER MUCH MUCH OF UPPER MICHIGAN TODAY. WITH THE COLD AIR ADVECTION IN PLACE THROUGH MUCH OF TONIGHT...THOSE GUSTS WILL LIKELY KEEP UP AS WINDS SHIFT TO THE WEST THROUGH THE NIGHT. WHILE THE KEWEENAW MAY BE PROTECTED SLIGHTLY TODAY...THE WINDS SHOULD REALLY KICK IN TONIGHT AS IT IS CLOSEST TO THE TIGHTEST PRESSURE GRADIENT WITH THE DEPARTING LOW AND RESULTING STRONGER WINDS JUST ABOVE THE SURFACE. EXPECT THERE TO BE A PERIOD THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS WHERE GUSTS IN THE KEWEENAW WILL BE BETWEEN 30-35KTS. FINALLY FOR TEMPERATURES...VALUES THIS MORNING HAVE BEEN CONSISTENT IN THE 50S OVER THE INTERIOR LOCATIONS...ALTHOUGH LOCATIONS NEAR THE COOLING OF THE GREAT LAKES HAVE BEEN BOUNCING UP AND DOWN DEPENDING ON THE WIND DIRECTION. WITH THE WARM START AND THE WARM FRONT PUSHING NORTHEAST THROUGH MUCH OF UPPER MICHIGAN TODAY...SHOULD SEE TEMPERATURES RISE INTO THE MID-UPPER 60S OVER THE CENTRAL/EASTERN CWA AND WHERE SOME SUNSHINE OCCURS WILL PROBABLY SEE SOME SITES HITTING THE 70 DEGREE MARK. COLDER AIR ARRIVING BEHIND THE COLD FRONT WILL LEAD TO FALLING TEMPS OVER THE WEST IN THE AFTERNOON AND THE REST OF THE AREA TOWARDS EVENING. THE CLOUD COVER TONIGHT WILL KEEP TEMPS A LITTLE ABOVE NORMAL AND HAVE LOWS IN THE LOWER 40S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 431 PM EDT THU MAY 8 2014 A SOMEWHAT PROGRESSIVE PATTERN IN THE LONG TERM WILL KEEP THE OVERALL PERIOD DAMP WITH TEMPS AROUND AVERAGE THIS WEEKEND AND SLIGHTLY BELOW AVERAGE NEXT WEEK. A WEAK BLOCKING SETUP OVER THE CENTRAL CONUS TODAY WILL BEGIN BREAKING DOWN OVERNIGHT AS A STRONG SHORTWAVE TROUGH EJECTS NORTHEASTWARD OUT OF THE CENTRAL PLAINS. THIS TROUGH WILL PUSH EASTWARD INTO A SHARP RIDGE EXTENDING NORTHWARD OVER HUDSON BAY. DEEP TROUGHING DEVELOPING OVER THE GULF OF ALASKA TODAY WILL THEN TRACK TO THE SOUTHERN ROCKIES BY SUNDAY NIGHT AND SETUP A PATTERN FAIRLY SIMILAR TO THE PAST COUPLE DAYS...WITH DEEP TROUGHING OVER CENTRAL NORTH AMERICA AND A RIDGE BUILDING ACROSS THE EASTERN CONUS. THE TROUGH WILL SHIFT NORTHEASTWARD EARLY NEXT WEEK...WITH BROAD TROUGHING DEVELOPING OVER THE GREAT LAKES REGION BY MID-WEEK. FRIDAY NIGHT...THE TROUGH AXIS APPROACHING THE AREA TODAY WILL CROSS OVER THE CWA BETWEEN 15 AND 21Z FRIDAY. HOWEVER...A REINFORCING TROUGH ROTATING AROUND A CLOSED MID-LEVEL LOW OVER NORTHERN SASKATCHEWAN WILL TRACK IN BEHIND THIS LEADING TROUGH AXIS AND CONTINUE CHANCES FOR PRECIP THROUGH MUCH OF FRIDAY NIGHT. MOISTURE AVAILABILITY LESSENS BY THIS TIME...SO DO NOT EXPECT ANYTHING MORE THAN SOME SCATTERED LIGHT SHOWERS SHIFTING FROM WEST TO EAST FRIDAY NIGHT. SATURDAY LOOKS TO BE THE ONLY TRUE DRY DAY IN THE EXTENDED FORECAST WITH A WEAK MID-LEVEL RIDGE BUILDING ACROSS THE UPPER MS VALLEY. A PUSH OF 0 TO 2C H8 TEMPS BEHIND FRIDAYS SYSTEM WILL LEAD TO A COOLER DAY THAN FRIDAY...BUT SUBSTANTIAL DRY AIR THROUGH THE COLUMN WILL RESULT IN MOSTLY SUNNY SKIES WITH SOME AFTERNOON CUMULUS AWAY FROM THE GREAT LAKES. HIGHS SHOULD MAKE IT TO THE LOW 60S INLAND...BUT STRUGGLE TO REACH 50 VERY NEAR SHORELINE LOCATIONS DOWNWIND OF LAKE SUPERIOR WITH WESTERLY FLOW. AS FOR FIRE WX CONCERNS...TEMPS WILL BE AT OR SLIGHTLY ABOVE AVERAGE WITH MIN RH VALUES IN THE MID 20S TO LOW 30S ACROSS MUCH OF THE INTERIOR...AND WINDS GUSTING TO AROUND 20MPH. SATURDAY NIGHT AND SUNDAY...A DECAYING TROUGH AXIS ENTERING THE RIDGE OVER A WEAK SFC WARM FRONT TRACKING IN FROM THE SW WILL YIELD SOME SCATTERED RAIN SHOWERS ACROSS MAINLY THE WESTERN AND CENTRAL CWA. THIS WILL KEEP SKIES MOSTLY CLOUDY THROUGH SUNDAY. THE FRONT LOOKS TO STALL ALONG LAKE SUPERIOR...SO QUITE A CONTRAST IN TEMPS WILL BE POSSIBLE AS THE KEWEENAW AND EASTERN CWA REMAIN IN THE UPPER 40S TO MID 50S IN SE FLOW WHILE THE INTERIOR WEST SEES TEMPS IN THE MID TO UPPER 60S UNDER WITH SW FLOW. SUNDAY NIGHT THROUGH TUESDAY...THE DEVELOPING TROUGH ACROSS THE PLAINS WILL BEGIN SHIFTING EASTWARD ACROSS THE MID AND UPPER MS VALLEY SUNDAY NIGHT. THIS WILL BRING SCATTERED TO NUMEROUS SHOWERS AND SOME EMBEDDED THUNDERSTORMS ACROSS THE AREA. HOWEVER...TIMING AND OVERALL COVERAGE IS STILL IN QUESTION AS THE GFS IS SOMEWHAT MORE PROGRESSIVE WITH THE TROUGH COMPARED TO THE ECMWF AND THE GEM. WITH THAT SAID...THE BEST CHANCE FOR INCREASED COVERAGE AND HEAVIER SHOWERS/STORMS SHOULD BE MONDAY AFTERNOON THROUGH TUESDAY. WEDNESDAY AND THURSDAY...PERSISTENT CYCLONIC FLOW WILL CONTINUE OVER THE REGION AS THE TROUGH STALLS OVER HUDSON BAY AND NORTHERN ONTARIO. WITH N TO NW FLOW...CLOUD COVER...AND H8 TEMPS OF -4 TO -8C...TEMPS WILL STRUGGLE TO GET OUT OF THE 40S ACROSS THE NORTH HALF AND THE LOW 50S FOR THE SOUTH HALF. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 128 AM EDT FRI MAY 9 2014 SHOWERS AND SCT TSRA WILL LIFT TO THE NE THROUGH UPPER MICHIGAN OVERNIGHT. AS A RESULT...LOW LEVEL MOISTENING FROM THE RAIN AND S TO SE FLOW WILL KEEP OR DROP CIGS INTO THE IFR/LIFR RANGE TONIGHT. CONDITIONS WILL IMPROVE FRI MORNING AS WINDS BECOME SW AND GREATER DRYING/MIXING MOVES IN. A BRIEF PERIOD OF VFR CONDITIONS MAY DEVELOP BY AFTERNOON BUT LOWER MVFR CIGS ARE EXPECTED TO REDEVELOP OVER THE WEST AS ADDITIONAL MOISTURE WRAPS AROUND THE DEPARTING LOW PRESSURE SYSTEM. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 422 AM EDT FRI MAY 9 2014 A LOW PRESSURE SYSTEM NEAR DULUTH EARLY THIS MORNING WILL SLIDE NORTHEAST INTO ONTARIO TODAY. AS THIS OCCURS...WINDS WILL SHIFT AROUND TO THE SOUTHWESTERLY DIRECTION TODAY AND THEN TO THE WEST TONIGHT. EXPECT THE WINDS TO INCREASE FROM WEST TO EAST TODAY AND GENERALLY TO 25KTS TONIGHT...ALTHOUGH THERE COULD BE SOME GUSTS TO 30KTS OVER THE CENTRAL LAKE. THESE STRONGER WINDS...COMBINED WITH GRADUALLY DRYING LOWER LEVELS SHOULD LEAD TO A DIMINISHMENT OF THE DENSE FOG OVER LAKE SUPERIOR FROM SOUTHWEST TO NORTHEAST TODAY. OPTED TO EXTENDED THE DENSE FOG ADVISORY FOR LAKE SUPERIOR INTO THE AFTERNOON HOURS TO BETTER MATCH UP WITH THE INCREASING WINDS AND DRIER AIR. A HIGH PRESSURE RIDGE WILL THEN SLIDE OVER THE AREA ON SATURDAY AND LEAD TO WINDS FALLING BELOW 15KTS SATURDAY NIGHT. THESE LIGHT WINDS WILL REMAIN THROUGH SUNDAY EVENING. A LOW PRESSURE SYSTEM MOVING TOWARDS THE UPPER GREAT LAKES REGION FROM THE CENTRAL PLAINS ON SUNDAY NIGHT WILL LEAD TO INCREASING EASTERLY WINDS (TO 25KTS BY MONDAY EVENING). THEN AS THE LOW SHIFTS NORTHEAST INTO ONTARIO ON TUESDAY...WINDS WILL SHIFT TO THE SOUTHWEST AND STAY BELOW 20KTS. && .HYDROLOGY... ISSUED AT 456 AM EDT FRI MAY 9 2014 THE RAIN SHOWERS AND THUNDERSTORMS PRODUCING HEAVY RAIN HAVE NEARLY DEPARTED UPPER MICHIGAN EARLY THIS MORNING. BUT THEY HAVE LEFT RISING RIVER LEVELS IN THEIR WAKE...ESPECIALLY OVER WESTERN UPPER MICHIGAN WHERE THE HEAVIEST RAIN HAS FALLEN. THE KEWEENAW PENINSULA HAS SEEN AROUND 0.75 INCHES OVERNIGHT IN ADDITION TO THE INCH OF RAIN THAT FELL LAST NIGHT. THIS AS LED TO ANOTHER RISE OF THE TRAP ROCK RIVER OVER THE LAST COUPLE OF HOURS. IT HAS LEVELED OUT SOMEWHAT OVER THE LAST HOUR...BUT WITH A COUPLE HOURS LEFT OF RAIN AND SNOW MELT CONTINUING WOULD EXPECT A LITTLE MORE RISE THIS MORNING. IT DID BRIEFLY REACH 10.15FT...WHICH PUTS THE CURRENT CREST AT THE 4TH HIGHEST ON RECORD. WARM TEMPERATURES TODAY WILL CONTINUE THE MELTING FROM A FEW INCHES OF SNOW WATER EQUIVALENT SHOWN FROM NOHRSC MODEL FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /WARMER FCST TEMPS FOR THE REST OF THIS WEEK/ IMPACT DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND...BUT IT WILL KEEP THE RIVER LEVELS HIGH INTO EARLY NEXT WEEK. IN ADDITION...WIDESPREAD RAIN IS EXPECTED AGAIN ON MONDAY AND THE CURRENT FORECAST CALLS FOR AROUND A HALF AN INCH OF ACCUMULATION. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KLUBER AVIATION...JLB MARINE...SRF HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
445 AM EDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 444 AM EDT FRI MAY 9 2014 THE UPPER TROUGH THAT HAS BEEN CONTROLLING OUR WEATHER FOR THE LAST COUPLE OF DAYS IS CURRENTLY MOVING NORTHEAST THROUGH THE CENTRAL PLAINS. MOISTURE LADEN AIR STREAMING NORTHEAST AHEAD OF THIS TROUGH CAN BE SEEN ON WV IMAGERY EARLY THIS MORNING...WHICH IS HELPING TO FUEL SHOWERS AND ISOLATED THUNDERSTORMS FROM WESTERN LAKE SUPERIOR THROUGH PORTIONS OF UPPER MICHIGAN...AND SOUTHEAST TO EASTERN WISCONSIN. AT THE SURFACE...A 998MB LOW IS LOCATED JUST SOUTHWEST OF DULUTH AND A WARM FRONT STRETCHES EAST ALONG THE U.P. AND WISCONSIN BORDER. SHORTWAVES EMBEDDED WITHIN THE WARM MOIST SOUTHWESTERLY FLOW CONTINUES TO PRODUCE AREAS OF THUNDERSTORMS OVER THE WESTERN HALF OF THE GREAT LAKES REGION AND EXPECT THAT TO CONTINUE FOR AREAS WITHIN THE WARM/MOIST AIRMASS. AS THE LOW LIFTS NORTHEAST TODAY...THE COLD FRONT (CURRENTLY STRETCHING SOUTH FROM SOUTHEAST MINNESOTA THROUGH NORTHERN MISSOURI) WILL SWEEP NORTHEAST ACROSS THE UPPER GREAT LAKES REGION. WITH THE SHOWER/THUNDERSTORM COVERAGE STARTING TO BECOME MORE SCATTERED/ISOLATED...WILL FOLLOW THAT IDEA FOR POPS AHEAD OF THE COLD FRONT. ALREADY STARTING TO SEE THE AFFECT OF THE DRYING ALOFT OVER NORTHWEST WISCONSIN AND EXPECT THE LAST AREAS OF SHOWERS FOR THIS MORNING TO PUSH THROUGH WESTERN UPPER MICHIGAN OVER THE NEXT COUPLE OF HOURS. AS THAT DRYING SHIFTS EAST THIS MORNING...WILL DIMINISH POPS FROM WEST TO EAST DURING THE MORNING HOURS. WITH THERE STILL BEING SOME ISOLATED THUNDER ON THE BACK EDGE OF THE PRECIPITATION (EVEN THOUGH RAP ANALYSIS OF MUCAPE AND MID-LEVEL LAPSE RATE VALUES ARE VERY WEAK)...HAVE EXTENDED THE SLIGHT CHANCE OF THUNDER A LITTLE LONGER OVER THE EAST THIS MORNING TO COINCIDE WITH THE AXIS OF MOISTURE AND LATEST THUNDER AREAS. BEHIND THE COLD FRONT...MAY SEE A FEW PEAKS OF SUNSHINE OVER THE CENTRAL/EAST (WHERE FOG ISN/T OCCURRING) AS THIS MID LEVEL DRY SLOT MOVES THROUGH AND BEFORE THE NEXT WAVE OF LOW LEVEL MOISTURE AND PRECIPITATION (CURRENTLY IN THE EASTERN DAKOTAS AND WESTERN MINNESOTA) MOVES OVER THE AREA. WILL CONTINUE THE IDEA SHOWN IN THE PREVIOUS FORECAST OF ISOLATED TO SCATTERED SHOWERS MOVING OVER THE WEST OR NORTHWEST HALF OF THE CWA LATER THIS AFTERNOON AND CONTINUING THROUGH A GOOD PORTION OF THE NIGHT TONIGHT (ESPECIALLY THE KEWEENAW TONIGHT). QPF AMOUNTS WILL BE MUCH LIGHTER THAN SEEN OVER THE LAST COUPLE DAYS AND MAINLY BETWEEN A TRACE AND A COUPLE TENTHS. IN ADDITION...IT WILL BECOME BREEZY BEHIND THE COLD FRONT...WITH BUFKIT SOUNDINGS INDICATING GUSTS AROUND 25KTS OVER MUCH MUCH OF UPPER MICHIGAN TODAY. WITH THE COLD AIR ADVECTION IN PLACE THROUGH MUCH OF TONIGHT...THOSE GUSTS WILL LIKELY KEEP UP AS WINDS SHIFT TO THE WEST THROUGH THE NIGHT. WHILE THE KEWEENAW MAY BE PROTECTED SLIGHTLY TODAY...THE WINDS SHOULD REALLY KICK IN TONIGHT AS IT IS CLOSEST TO THE TIGHTEST PRESSURE GRADIENT WITH THE DEPARTING LOW AND RESULTING STRONGER WINDS JUST ABOVE THE SURFACE. EXPECT THERE TO BE A PERIOD THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS WHERE GUSTS IN THE KEWEENAW WILL BE BETWEEN 30-35KTS. FINALLY FOR TEMPERATURES...VALUES THIS MORNING HAVE BEEN CONSISTENT IN THE 50S OVER THE INTERIOR LOCATIONS...ALTHOUGH LOCATIONS NEAR THE COOLING OF THE GREAT LAKES HAVE BEEN BOUNCING UP AND DOWN DEPENDING ON THE WIND DIRECTION. WITH THE WARM START AND THE WARM FRONT PUSHING NORTHEAST THROUGH MUCH OF UPPER MICHIGAN TODAY...SHOULD SEE TEMPERATURES RISE INTO THE MID-UPPER 60S OVER THE CENTRAL/EASTERN CWA AND WHERE SOME SUNSHINE OCCURS WILL PROBABLY SEE SOME SITES HITTING THE 70 DEGREE MARK. COLDER AIR ARRIVING BEHIND THE COLD FRONT WILL LEAD TO FALLING TEMPS OVER THE WEST IN THE AFTERNOON AND THE REST OF THE AREA TOWARDS EVENING. THE CLOUD COVER TONIGHT WILL KEEP TEMPS A LITTLE ABOVE NORMAL AND HAVE LOWS IN THE LOWER 40S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 431 PM EDT THU MAY 8 2014 A SOMEWHAT PROGRESSIVE PATTERN IN THE LONG TERM WILL KEEP THE OVERALL PERIOD DAMP WITH TEMPS AROUND AVERAGE THIS WEEKEND AND SLIGHTLY BELOW AVERAGE NEXT WEEK. A WEAK BLOCKING SETUP OVER THE CENTRAL CONUS TODAY WILL BEGIN BREAKING DOWN OVERNIGHT AS A STRONG SHORTWAVE TROUGH EJECTS NORTHEASTWARD OUT OF THE CENTRAL PLAINS. THIS TROUGH WILL PUSH EASTWARD INTO A SHARP RIDGE EXTENDING NORTHWARD OVER HUDSON BAY. DEEP TROUGHING DEVELOPING OVER THE GULF OF ALASKA TODAY WILL THEN TRACK TO THE SOUTHERN ROCKIES BY SUNDAY NIGHT AND SETUP A PATTERN FAIRLY SIMILAR TO THE PAST COUPLE DAYS...WITH DEEP TROUGHING OVER CENTRAL NORTH AMERICA AND A RIDGE BUILDING ACROSS THE EASTERN CONUS. THE TROUGH WILL SHIFT NORTHEASTWARD EARLY NEXT WEEK...WITH BROAD TROUGHING DEVELOPING OVER THE GREAT LAKES REGION BY MID-WEEK. FRIDAY NIGHT...THE TROUGH AXIS APPROACHING THE AREA TODAY WILL CROSS OVER THE CWA BETWEEN 15 AND 21Z FRIDAY. HOWEVER...A REINFORCING TROUGH ROTATING AROUND A CLOSED MID-LEVEL LOW OVER NORTHERN SASKATCHEWAN WILL TRACK IN BEHIND THIS LEADING TROUGH AXIS AND CONTINUE CHANCES FOR PRECIP THROUGH MUCH OF FRIDAY NIGHT. MOISTURE AVAILABILITY LESSENS BY THIS TIME...SO DO NOT EXPECT ANYTHING MORE THAN SOME SCATTERED LIGHT SHOWERS SHIFTING FROM WEST TO EAST FRIDAY NIGHT. SATURDAY LOOKS TO BE THE ONLY TRUE DRY DAY IN THE EXTENDED FORECAST WITH A WEAK MID-LEVEL RIDGE BUILDING ACROSS THE UPPER MS VALLEY. A PUSH OF 0 TO 2C H8 TEMPS BEHIND FRIDAYS SYSTEM WILL LEAD TO A COOLER DAY THAN FRIDAY...BUT SUBSTANTIAL DRY AIR THROUGH THE COLUMN WILL RESULT IN MOSTLY SUNNY SKIES WITH SOME AFTERNOON CUMULUS AWAY FROM THE GREAT LAKES. HIGHS SHOULD MAKE IT TO THE LOW 60S INLAND...BUT STRUGGLE TO REACH 50 VERY NEAR SHORELINE LOCATIONS DOWNWIND OF LAKE SUPERIOR WITH WESTERLY FLOW. AS FOR FIRE WX CONCERNS...TEMPS WILL BE AT OR SLIGHTLY ABOVE AVERAGE WITH MIN RH VALUES IN THE MID 20S TO LOW 30S ACROSS MUCH OF THE INTERIOR...AND WINDS GUSTING TO AROUND 20MPH. SATURDAY NIGHT AND SUNDAY...A DECAYING TROUGH AXIS ENTERING THE RIDGE OVER A WEAK SFC WARM FRONT TRACKING IN FROM THE SW WILL YIELD SOME SCATTERED RAIN SHOWERS ACROSS MAINLY THE WESTERN AND CENTRAL CWA. THIS WILL KEEP SKIES MOSTLY CLOUDY THROUGH SUNDAY. THE FRONT LOOKS TO STALL ALONG LAKE SUPERIOR...SO QUITE A CONTRAST IN TEMPS WILL BE POSSIBLE AS THE KEWEENAW AND EASTERN CWA REMAIN IN THE UPPER 40S TO MID 50S IN SE FLOW WHILE THE INTERIOR WEST SEES TEMPS IN THE MID TO UPPER 60S UNDER WITH SW FLOW. SUNDAY NIGHT THROUGH TUESDAY...THE DEVELOPING TROUGH ACROSS THE PLAINS WILL BEGIN SHIFTING EASTWARD ACROSS THE MID AND UPPER MS VALLEY SUNDAY NIGHT. THIS WILL BRING SCATTERED TO NUMEROUS SHOWERS AND SOME EMBEDDED THUNDERSTORMS ACROSS THE AREA. HOWEVER...TIMING AND OVERALL COVERAGE IS STILL IN QUESTION AS THE GFS IS SOMEWHAT MORE PROGRESSIVE WITH THE TROUGH COMPARED TO THE ECMWF AND THE GEM. WITH THAT SAID...THE BEST CHANCE FOR INCREASED COVERAGE AND HEAVIER SHOWERS/STORMS SHOULD BE MONDAY AFTERNOON THROUGH TUESDAY. WEDNESDAY AND THURSDAY...PERSISTENT CYCLONIC FLOW WILL CONTINUE OVER THE REGION AS THE TROUGH STALLS OVER HUDSON BAY AND NORTHERN ONTARIO. WITH N TO NW FLOW...CLOUD COVER...AND H8 TEMPS OF -4 TO -8C...TEMPS WILL STRUGGLE TO GET OUT OF THE 40S ACROSS THE NORTH HALF AND THE LOW 50S FOR THE SOUTH HALF. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 128 AM EDT FRI MAY 9 2014 SHOWERS AND SCT TSRA WILL LIFT TO THE NE THROUGH UPPER MICHIGAN OVERNIGHT. AS A RESULT...LOW LEVEL MOISTENING FROM THE RAIN AND S TO SE FLOW WILL KEEP OR DROP CIGS INTO THE IFR/LIFR RANGE TONIGHT. CONDITIONS WILL IMPROVE FRI MORNING AS WINDS BECOME SW AND GREATER DRYING/MIXING MOVES IN. A BRIEF PERIOD OF VFR CONDITIONS MAY DEVELOP BY AFTERNOON BUT LOWER MVFR CIGS ARE EXPECTED TO REDEVELOP OVER THE WEST AS ADDITIONAL MOISTURE WRAPS AROUND THE DEPARTING LOW PRESSURE SYSTEM. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 422 AM EDT FRI MAY 9 2014 A LOW PRESSURE SYSTEM NEAR DULUTH EARLY THIS MORNING WILL SLIDE NORTHEAST INTO ONTARIO TODAY. AS THIS OCCURS...WINDS WILL SHIFT AROUND TO THE SOUTHWESTERLY DIRECTION TODAY AND THEN TO THE WEST TONIGHT. EXPECT THE WINDS TO INCREASE FROM WEST TO EAST TODAY AND GENERALLY TO 25KTS TONIGHT...ALTHOUGH THERE COULD BE SOME GUSTS TO 30KTS OVER THE CENTRAL LAKE. THESE STRONGER WINDS...COMBINED WITH GRADUALLY DRYING LOWER LEVELS SHOULD LEAD TO A DIMINISHMENT OF THE DENSE FOG OVER LAKE SUPERIOR FROM SOUTHWEST TO NORTHEAST TODAY. OPTED TO EXTENDED THE DENSE FOG ADVISORY FOR LAKE SUPERIOR INTO THE AFTERNOON HOURS TO BETTER MATCH UP WITH THE INCREASING WINDS AND DRIER AIR. A HIGH PRESSURE RIDGE WILL THEN SLIDE OVER THE AREA ON SATURDAY AND LEAD TO WINDS FALLING BELOW 15KTS SATURDAY NIGHT. THESE LIGHT WINDS WILL REMAIN THROUGH SUNDAY EVENING. A LOW PRESSURE SYSTEM MOVING TOWARDS THE UPPER GREAT LAKES REGION FROM THE CENTRAL PLAINS ON SUNDAY NIGHT WILL LEAD TO INCREASING EASTERLY WINDS (TO 25KTS BY MONDAY EVENING). THEN AS THE LOW SHIFTS NORTHEAST INTO ONTARIO ON TUESDAY...WINDS WILL SHIFT TO THE SOUTHWEST AND STAY BELOW 20KTS. && .HYDROLOGY... ISSUED AT 431 PM EDT THU MAY 8 2014 WET WEATHER WILL RETURN INTO FRIDAY NIGHT...THEN RETURN AGAIN BY EARLY NEXT WEEK. MOST OF THE RAIN LOOKS TO FALL OVER THE STURGEON RIVER BASIN THIS EVENING. ADDING TO THIS WILL BE SOME MELTING FROM A FEW INCHES OF SNOW WATER EQUIVALENT SHOWN FROM NOHRSC MODEL FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /WARMER FCST TEMPS FOR THE REST OF THIS WEEK/ IMPACT DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS WILL AFFECT THE AREA INTO EARLY FRIDAY. RAINFALL AMOUNTS WILL LIKELY EXCEED A HALF OF AN INCH FOR MUCH OF WESTERN UPPER MICHIGAN...AND LOCALIZED AMOUNTS OVER AN INCH SHOULD OCCUR WHERE THUNDERSTORMS TRACK. THIS WILL KEEP THE RIVER LEVELS HIGH INTO EARLY NEXT WEEK. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KLUBER AVIATION...JLB MARINE...SRF HYDROLOGY...KLUBER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
340 AM CDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT FRI MAY 9 2014 RAP ANALYZED SURFACE LOW JUST SOUTH OF DULUTH EARLY THIS MORNING. AREAS WEST OF THE METRO HAVE SEEN THE WINDS TURN WESTERLY AND PICK UP IN INTENSITY. COLD AIR ADVECTION IS ONGOING IN THESE AREAS...AND WILL CONTINUE TO SPREAD ACROSS THE REMAINDER OF THE FORECAST AREA TODAY. THE SURFACE LOW WILL SLOWLY CONTINUE NORTHEASTWARD...AS THE WESTERLY WINDS TAKE MUCH OF THE DAY TO SPREAD ACROSS WEST CENTRAL WISCONSIN. ABUNDANT LOW LEVEL MOISTURE WILL ALLOW FOR LOW LCL HEIGHTS WHICH IS CURRENTLY NOTICEABLE IN THE OBSERVATIONS BEHIND THE COLD FRONT WHERE CEILINGS UNDER 1K FEET ARE PRESENT. RAP AND NAM MODEL SOUNDINGS INDICATE THIS MOISTURE STICKING AROUND FOR MUCH OF THE DAY...SO TRENDED TOWARD A MORE PESSIMISTIC SKY COVER FORECAST AND HENCE LOWERED MAX TEMPERATURES TODAY BY A FEW DEGREES ACROSS THE FA. MAX TEMPS WILL BE ABOUT 10 DEGREES BELOW SEASONAL NORMALS FOR THIS TIME OF YEAR. IN ADDITION...WRAP AROUND LIGHT RAIN SHOWERS ARE EXPECTED TO MOVE ACROSS THE NORTHERN PORTION OF THE CWA AS THEY CYCLONIC CIRCULATION ALOFT REMAINS BETTER TOWARD THE NORTH /AS WELL AS AT LEAST SOME FGEN AND FN VECTOR CONVERGENCE/. SKIES WILL BEGIN CLEARING LATE THIS AFTERNOON AND MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT...EXCEPT CLOUDS WILL QUICKLY BEGIN FILLING IN FROM THE SOUTHWEST EARLY SATURDAY MORNING. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 340 AM CDT FRI MAY 9 2014 AN UNSETTLED PERIOD REMAINS FORECAST FOR MUCH OF THE LONGER TERM AS NORTHERN AND SOUTHERN STREAM ENERGY EVENTUALLY PHASE OVER THE CENTER OF THE COUNTRY AROUND THE MIDDLE OF NEXT WEEK. THIS PROCESS OCCURS THE FASTEST WITH THE GFS WHILE DP/DT SHOWS THAT THE SLOWER ECMWF IS BECOMING EVEN SLOWER WITH TIME. ON SATURDAY...A WAVE MOVING IN FROM THE CENTRAL PLAINS WILL BRING THICKENING CLOUDINESS AND SHOWERS BACK ACROSS THE FA FROM SW TO NE DURING THE DAY. A BRIEF BREAK IN THE PRECIPITATION IS EXPECTED SATURDAY NIGHT BEFORE A MORE POTENT WAVE BEGINS TO TAKE SHAPE OVER THE CENTRAL PLAINS ON SUNDAY. THIS WAVE IS BEING DRIVEN BY THE SOUTHERN STREAM ENERGY. USING THE SLOWER ECWMF...THE LOW IN THE PLAINS TAKES UNTIL MONDAY EVENING TO ARRIVE IN SE MN. THIS PLACES MUCH OF THE FA IN LOW LEVEL THETA-E ADVECTION FROM SUNDAY THROUGH MONDAY...WITH SOUTHERN MN BEARING THE BRUNT OF IT. HENCE...LIKELY POPS STREAM BACK IN ON SUNDAY FROM THE SOUTHWEST AND PERSIST THROUGH MONDAY. WIDESPREAD HALF INCH TO ONE INCH RAINFALL IS LIKELY DURING THIS PERIOD WITH SOME TWO INCH AMOUNTS OVER SOUTHERN MN. THERE WILL CERTAINLY BE THE THREAT FOR SOME THUNDERSTORMS...ESPECIALLY ON MONDAY FROM THE TWIN CITIES ON EAST AND SOUTH. STRICTLY USING THE ECMWF TIMING WOULD INDICATE A WINDOW OF OPPORTUNITY FOR STRONG TO SEVERE STORMS MONDAY AFTERNOON/EVENING TO THE SOUTH AND EAST OF THE TWIN CITIES. THE SHOWERS WILL BEGIN TO TAPER OFF MONDAY NIGHT AS THE LOW PRESSURE SYSTEM MOVES NORTHEAST OF THE FA. INSTABILITY SHOWERS ARE POSSIBLE MAINLY FROM CENTRAL MINNESOTA ON NORTHWARD ON TUESDAY. SCATTERED SHOWERS ARE BACK FOR MUCH OF THE FA WEDNESDAY AND THURSDAY AS THE UPPER TROUGH COMES TOGETHER FROM THE UPPER MISSISSIPPI VALLEY TO THE GULF COAST. HIGH TEMPERATURES WILL BE CLOSE TO NORMAL THIS WEEKEND...BUT THEN RETREAT TO SOME 10 TO 15 DEGREES BELOW NORMAL FOR THE MIDDLE TO END OF NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1248 AM CDT FRI MAY 9 2014 ALL THUNDERSTORM ACTIVITY HAS EXITED THE FORECAST AREA...WITH THE CONCERN TURNING TO THE IFR AND LIFR CI GS BEING OBSERVED ACROSS PARTS OF WESTERN AND CENTRAL MINNESOTA AT THIS TIME. THE RAP ANALYZED CENTER OF THE SURFACE LOW IS ADVANCING NORTHWARD AND IS NOW POSITIONED OVER THE NORTH METRO. WIDESPREAD FOG HAS DEVELOPED ACROSS THE REGION WHICH WAS ADDED AT MOST TAF SITES. OVERALL CHANGES FROM THE PREVIOUS FORECAST INCLUDE A MUCH MORE PESSIMISTIC COG FORECAST THROUGH THE OVERNIGHT AND THE DAY. LATEST RUNS OF BOTH THE RAP AND NAM INDICATE SOLID VERY LOW LEVEL MOISTURE ACROSS THE BOARD ON MODEL SOUNDINGS...AND LASTING LONGER THAN PREVIOUSLY FORECAST. MOST SITES WILL SEE AT LEAST IFR CI GS THROUGH THE OVERNIGHT...THEN MVFR OR LOWER THROUGH MOST OF THE DAY. WITH THE LOW BEING IN THE CENTER OF THE FORECAST AREA...WIND DIRECTION IS COMPLETELY RELATIVE TO EACH SITES LOCATION RELATIVE THE TO COUNTER CLOCKWISE CIRCULATION AT THIS TIME...BUT ALL SITES WILL GRADUALLY SWITCH TO A WESTERLY WIND. WINDS WILL BE STRONG TOMORROW...WITH GUSTS OVER 20 KNOTS LIKELY. SKIES BEGIN TO CLEAR FRIDAY NIGHT. KMSP...STARTING THE PERIOD ON THE EDGE OF THE IFR CIGS...AND FOG HAS ALREADY DEVELOPED AT THE TERMINAL. IFR WILL SET IN THROUGH THE OVERNIGHT HOURS AND GRADUALLY LIFT DURING THE MORNING. MVFR OR LOWER CIGS ARE EXPECTED INTO THE AFTERNOON. WINDS WILL SHIFT SOUTHERLY VERY SOON...THEN TURN WESTERLY. /OUTLOOK FOR KMSP/ SAT...VFR. CHC -TSRA. WINDS SSE 10KTS. SUN...MVFR POSSIBLE. LIKELY -SHRA. WINDS SW TO NW 10-15 KTS. MON...MVFR POSSIBLE. LIKELY -SHRA. WINDS NW 10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...SPD LONG TERM...RAH AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
101 AM CDT FRI MAY 9 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 400 PM CDT THU MAY 8 2014 WIDESPREAD THUNDERSTORMS ONGOING ACROSS THE FORECAST AREA. THE CURRENT LINE OF STORMS IS THE FIRST OF TWO LINES EXPECTED OVER THE NEXT SEVERAL HOURS. WIND AND HAIL WILL CONTINUE TO BE A THREAT AND THE SECOND LINE WILL ALSO HAVE A TORNADO POTENTIAL...ESPECIALLY FOR STORMS THAT REMAIN NEAR THE WARM FRONT IN SOUTHERN MN. THERE HAS BEEN MODERATE INCREASES IN SBCAPE AND MLCAPE ALONG AND SOUTH OF THE I-90 CORRIDOR IN FAR SOUTHERN MN OVER THE PAST 2-3 HOURS WITH THE 1000-1500 J/KG NOW BEING OBSERVED. NORTH OF THE WARM FRONT THERE REMAINS A SEVERE WIND AND HAIL THREAT. THE WIND THREAT WAS SOMEWHAT UNEXPECTED DUE TO THE LACK OF SURFACE ROOTED STORMS...BUT THE FORCING AND INSTABILITY ABOVE THE SURFACE BASED CIN IS OBVIOUSLY ENOUGH TO OVERCOME AND WE ARE GETTING WINDS OF 40-70 MPH DOWN TO THE SURFACE WITH THE MORE ORGANIZED LINES AND BOWING SEGMENTS. THIS THREAT SHOULD CONTINUE INTO THE EARLY EVENING FOR WEST CENTRAL WI ESPECIALLY FOR CONVECTIVE LINES THAT ARE PERPENDICULAR TO SOUTHWEST TO NORTHEAST ORIENTATED DEEP LAYER SHEAR VECTORS. DRYING IN THE WATER VAPOR NOW ENTERING FAR SOUTHWEST MN AND WILL BE THE TRIGGER FOR A SECOND ROUND OF STORMS WITH THE POTENTIAL FOR HAIL...WINDS AND EVEN TORNADOES ACROSS SOUTHERN MN. THE STRONG DYNAMIC FORCING WILL CONTINUE TO LIFT THE WARM FRONT...BUT SURFACE HEATING HAS BEEN LIMITED BY CONVECTIVE DEBRIS AND CLOUD COVER. NONETHELESS...THE SECOND LINE OF STORMS WILL HAVE HIGHER END POTENTIAL AND THE ENVIRONMENT IN SOUTH CENTRAL MN WILL SUPPORT SUPERCELLS BETWEEN 5 PM AND 8 PM. WRAP AROUND SHOWERS WILL BE POSSIBLE LATE TONIGHT AND EARLY FRIDAY AS THE UPPER LOW SLOWLY MOVES NORTHEAST OF THE FORECAST AREA. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 400 PM CDT THU MAY 8 2014 THE LONGER TERM CONTINUES TO POSE SIGNIFICANT TIMING AND OVERALL DEVELOPMENT ISSUES WITH THE WESTERN/CENTRAL CONUS TROUGH DURING THE PERIOD. INITIALLY THE GFS AND ECMWF ARE IN FAIR AGREEMENT WITH THE SHORT WAVE TROUGH MOVING THROUGH SATURDAY INTO SUNDAY. STILL CONSTITUTES HIGHER CHANCE POPS AT THE MOMENT. AFTER THAT...THE LONGER TERM MODELS DIVERGE ON TIMING AND DEVELOPMENT OF THE TROUGH OVER THE AREA INTO NEXT WEEK. THE ECMWF IS MORE AMPLIFIED WITH THE SYSTEM...WITH NORTHERN AND SOUTHERN STREAMS GRADUALLY MERGING AND LIFTING A FAIRLY SIGNIFICANT TROUGH/SURFACE LOW NORTHEAST TOWARD THE GREAT LAKES BY MIDWEEK. THIS COULD INCLUDE THE THREAT OF STRONG/SEVERE STORMS AS WELL. WILL HAVE TO CONTINUE TO MONITOR MODEL TRENDS WITH THIS SYSTEM. BOTH MODELS TREND COLDER AIR FILTERING INTO THE NORTHERN CONUS AS THE TROUGH DIGS SOUTH AND EAST. HIGHS WILL ONLY BE IN THE 50S AND LOWS WILL BE DROPPING INTO THE MIDDLE 30S WHICH WILL CONTINUE THE THREAT FOR FROST FROM WEDNESDAY INTO THE FOLLOWING WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1248 AM CDT FRI MAY 9 2014 ALL THUNDERSTORM ACTIVITY HAS EXITED THE FORECAST AREA...WITH THE CONCERN TURNING TO THE IFR AND LIFR CIGS BEING OBSERVED ACROSS PARTS OF WESTERN AND CENTRAL MINNESOTA AT THIS TIME. THE RAP ANALYZED CENTER OF THE SURFACE LOW IS ADVANCING NORTHWARD AND IS NOW POSITIONED OVER THE NORTH METRO. WIDESPREAD FOG HAS DEVELOPED ACROSS THE REGION WHICH WAS ADDED AT MOST TAF SITES. OVERALL CHANGES FROM THE PREVIOUS FORECAST INCLUDE A MUCH MORE PESSIMISTIC CIG FORECAST THROUGH THE OVERNIGHT AND THE DAY. LATEST RUNS OF BOTH THE RAP AND NAM INDICATE SOLID VERY LOW LEVEL MOISTURE ACROSS THE BOARD ON MODEL SOUNDINGS...AND LASTING LONGER THAN PREVIOUSLY FORECAST. MOST SITES WILL SEE AT LEAST IFR CIGS THROUGH THE OVERNIGHT...THEN MVFR OR LOWER THROUGH MOST OF THE DAY. WITH THE LOW BEING IN THE CENTER OF THE FORECAST AREA...WIND DIRECTION IS COMPLETELY RELATIVE TO EACH SITES LOCATION RELATIVE THE TO COUNTER CLOCKWISE CIRCULATION AT THIS TIME...BUT ALL SITES WILL GRADUALLY SWITCH TO A WESTERLY WIND. WINDS WILL BE STRONG TOMORROW...WITH GUSTS OVER 20 KNOTS LIKELY. SKIES BEGIN TO CLEAR FRIDAY NIGHT. KMSP...STARTING THE PERIOD ON THE EDGE OF THE IFR CIGS...AND FOG HAS ALREADY DEVELOPED AT THE TERMINAL. IFR WILL SET IN THROUGH THE OVERNIGHT HOURS AND GRADUALLY LIFT DURING THE MORNING. MVFR OR LOWER CIGS ARE EXPECTED INTO THE AFTERNOON. WINDS WILL SHIFT SOUTHERLY VERY SOON...THEN TURN WESTERLY. /OUTLOOK FOR KMSP/ SAT...VFR. CHC -TSRA. WINDS SSE 10KTS. SUN...MVFR POSSIBLE. LIKELY -SHRA. WINDS SW TO NW 10-15 KTS. MON...MVFR POSSIBLE. LIKELY -SHRA. WINDS NW 10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...DWE LONG TERM...DWE AVIATION...SPD
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1207 AM CDT Fri May 9 2014 .UPDATE... Issued at 730 PM CDT THU MAY 8 2014 Surprisingly busy evening. Shield of rain with embedded convection has proved to be interesting, with some isolated damage reports with brief bowing/spin up vorts in shallow convective cells/elements. Low level 0-1km helicity actually fairly stout over the Mo Ozarks this afternoon/evening. Overall trend of the eastern cwfa convection is downward and expect that trend to continue. Deeper scattered convection is occurring ahead of a cold front over eastern KS with the most notable updrafts w-nw-n of KCNU. Storms having a tough time of it, but still seeing a stronger updraft or two firing up. MLCAPE of around 1000 J/kg is occurring just ahead of the front, but drops off quite a bit has you head east-se into MO. 0-6km bulk shear more than adequate for storm organization where somewhat stronger instability occurs over se KS and far western MO later this evening. HRRR however, really not doing much with the existing convection owing to a lack of progged overall instability. Will watch trends, but the weakening trend of the HRRR looks good later this evening. Later tonight, a veering low level jet and moisture advection should allow some additional elevated convection to develop overnight into Friday morning ahead of the low level front with the approach of shortwave/upper jet max. && .SHORT TERM...(This Evening and Tonight) Issued at 300 PM CDT THU MAY 8 2014 An upper level trough is currently pushing east into the central Plains as an associated area of surface low pressure pushes northeast across eastern Nebraska. A cold front ALSO extends south from the low and is pushing east across central Kansas and Oklahoma. Convection is ongoing across the area. This activity formed over Oklahoma overnight and continues to develop and push to the northeast. These showers and thunderstorms will continue to track northeast across the area this afternoon into the early evening hours. Deep layer shear is on the weak side across the area. Instability is starting to increase across the eastern Ozarks as more heating was able to occur in these locations before clouds were able to overspread the area. The overall severe potential is on the low side with this activity, but with slightly better instability there could be a few strong wind gusts with any bow segments that can develop this afternoon and early this evening. This activity will push east of the area by the early to mid evening hours. The clouds are clearing from west to east across eastern Kansas into central Oklahoma behind this convection. We will have to see how far east the clearing can make it this afternoon/early this evening. The clearing will likely make it over to the far western portion of the forecast area. Additional thunderstorms are expected to develop across northeastern Oklahoma into eastern Kansas along a cold front late this afternoon into this evening. This activity will then track to the northeast and may clip southeastern Kansas and far western Missouri. Deep layer wind shear will begin to increase from west to east this evening and if enough clearing occurs and enough instability can develop, hail in excess of quarters will be possible with stronger storms. These storms may congeal into a line and track east across the area. If the line does develop winds in excess of 60mph will be possible. There would also be a small risk for a brief tornado within this line generally northwest of a Columbus Kansas to Osceola Missouri Line this evening. The cold front will then slowly sag southeast towards the area late this evening into the overnight hours. Showers and thunderstorms are expected to develop and ride along the front overnight. The front will push over the far northern and western portions of the forecast area tonight. Locally heavy rainfall will occur where the training of storms can occur along the front. Due to the dry antecedent conditions the overall flood risk is low with this potential heavy rainfall. .LONG TERM...(Friday through Thursday) Issued at 300 PM CDT THU MAY 8 2014 An active weather pattern will continue Friday into early next week as the a couple storm system track through the region. Any convection that develops overnight tonight should push east of the area by Friday morning, with clearing expected behind this activity. The cold front will continue to track southeast through the area on Friday. Areas southeast of the front will become unstable. Better deep layer shear will be over the region on Friday afternoon allowing organized updrafts. Additional thunderstorms will develop along the front, and these storms will have the potential to become strong a severe. The main risk will be large hail with a few of the strongest storms capable of hail to golf balls generally along and southeast of the Interstate 44 corridor. The front will push south of the area Friday evening with dry conditions overnight Friday. The front will then lift back north across the area Saturday. Thunderstorms area expected to develop along and north of the front as it lifts through the region. A few of these storms could become strong to severe with large hail the main risk. South of the front instability will increase but there will not be much in a way of lift, and a cap will be increasing through the day as a warm air mass in the mid level spreads over the area. So, think all in all most of the activity will occur along and ahead of the front on Saturday. Another upper level system will track through the region late this weekend into early next week. Medium range models continue to differ on the track, timing, and strength of this system. The cold front will sag south then sweep through the region as the upper level trough approaches and sweeps through the region. Additional severe storm potential will be possible, but details/evolution of storms are lacking this far out in time. Northwest flow aloft pattern will setup over the region behind this system through the middle of next week behind this system. Cooler conditions will occur across the region in this northwest flow pattern. && .AVIATION...(For the 06Z TAFS through 06Z Friday Night) Issued at 1158 PM CDT THU MAY 8 2014 Scattered showers and thunderstorm will be possible for the regions terminals through 10z as a cold front moves very slowly to the east across Kansas. Ceilings will become MVFR across the area during the overnight hours with slowly improving flight conditions during the day on Friday. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ UPDATE...DSA SHORT TERM...Wise LONG TERM...Wise AVIATION...Hatch
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 PM CDT Thu May 8 2014 .UPDATE: Issued at 853 PM CDT Thu May 8 2014 A north to south area or band of showers and a few thunderstorms was moving slowly eastward through east central and southeast MO and west central and southwest IL. The intensity of the radar returns have weakened over the St Louis metro area with better rains both north and south. This precipitation was in a region of low-mid level warm air advection ahead of a southwest flow shortwave. This activity will eventually translate east of our forecast area later this evening, with a break in the precipitation expected until more showers and storms now across northwest and west central MO and southeast KS, along and just ahead of an approaching cold front, shifts into our forecast area late tonight. The HRRR model also tries to bring some of the convection now across AR northeastward into southeastern MO late tonight. Could not rule out isolated hail and strong wind gusts from the stronger storms late tonight. Mild temperatures should continue tonight with slight cooling, or cooler temperatures over the extreme northwestern portion of our forecast area behind the cold front. GKS && .SHORT TERM: (Through Late Tonight) Issued at 256 PM CDT Thu May 8 2014 SHRA/TSRA trends are the primary concern this evening, and are remaining very difficult to pin down. Early on, N-S band of showers and thunderstorms now moving into central MO will work its way east during the remainder of the afternoon and early evening. Have leaned heavily on the HRRR runs for trends over the next 3-6 hours, as it continues to provide superior guidance on the trends with this area of convection. Passage of the shortwave fueling this precip will likely cause area to diminish a bit in coverage and intensity during the evening, but additional (and hard to time) upstream shortwaves, as well as persistent WAA and associated isentropic ascent, should generate additional shower and thunderstorm activity during the late evening and overnight hours in the warm sector. Precip threat (especially in our NW counties) will also be driven by convection that forms along the cold front and works its way east with time. Truett .LONG TERM: (Friday through Next Thursday) Issued at 256 PM CDT Thu May 8 2014 Overnight elevated SHRA/TSRA forced by the LLJ will probably be ongoing at daybreak on Fri, at least over part of the CWA. As the core of the LLJ shifts northeastward into IL/IN, the greatest moisture convergence and forcing for pcpn will also shift out of the CWA. Consequently, there should be a decrease in precipitation coverage or perhaps even a lull during the mid to late morning hours on Fri. The absence of widespread precipitation combined with some breaks in the clouds should be sufficient for afternoon destabilization across the southeastern one-half to one-third of the CWA. This detail matters because a trough with a vort max in its base will be approaching from the west. Large scale ascent from DCVA as well as lift ahead of the cold front will likely occur in an environment with H7-H5 lapse rates of 6-7.5 deg C/km and 40-60 kts of 0-6 km bulk shear as well as nearly unidirectional wind profiles. These parameters are sufficient for severe thunderstorms with hail and wind as the primary threats. Although recent model runs all depict a solution where the cold front moves through most of the CWA on Fri night and then stalls in southern MO before lifting northward as a warm front on Sat, the effective boundary might end up much farther south by Sat morning depending on outflow boundaries from convection on Fri/Fri night. If this occurs, then the temperature forecast for Sat may be too warm. Shortwave ridging aloft is expected on Sat with a compact vort max moving across southern MN, which is much farther north than yesterday`s model runs. The H85 LLJ associated with the vort max moving across MN could produce enough lift over the warm front to support scattered SHRA/TSRA in MO/IL, especially if forecast H7-H5 lapse rates of 7-8 deg C/km are realized. SHRA/TSRA are also possible on Sat night due to moisture convergence along a strengthening southwesterly LLJ. A new trough develops out west over the weekend, inducing surface cyclogenesis over the plains and eventually sending another cold front through MO/IL early next week. Models disagree on how quickly the trough shifts eastward into the central CONUS, leading to disagreements on how quickly the cold front moves through the LSX CWA. It appears that there will be a period of northwest flow or cyclonic flow during the middle of next week depending on how the trough evolves. Expect cooler temperatures in such a pattern with precip chances dependent on shortwaves and moisture availability. Kanofsky && .AVIATION: (For the 06z TAFs through 06z Friday Night) Issued at 1148 PM CDT Thu May 8 2014 Showers have moved out of all of the terminals at the moment, but there are additional showers and scattered thunderstorms over western and southern Missouri that are moving toward them. Will continue with the same timing, though have narrowed the window as I do not think the rain will last more than 2-3 hours. There are MVFR ceilings currently at KIRK, and low MVFR ceilings over southeast Kansas and northeast Oklahoma which I expect to eventually spread into the terminals later tonight. These ceilings will eventually dissipate by mid-late morning on Friday. Still expect a broken line of storms to develop over east central Missouri around 21Z on Friday afternoon that will move east into Illinois by 00Z Friday evening. This is reflected by going TAF. Specifics for KSTL: Showers and scattered thunderstorms currently over southern and western Missouri will move into the terminal between 09-12Z. Expect this activity to have MVFR conditions associated with it that will last past when the rain is over. Conditions will improve by late morning. A broken line of thunderstorms will develop in the vicinity of KSTL around 21Z on Friday and then move east into Illinois thereafter. Britt && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BISMARCK ND
102 AM CDT FRI MAY 9 2014 .UPDATE... ISSUED AT 1259 AM CDT FRI MAY 9 2014 TRIMMED POPS SLIGHTLY ACROSS THE SOUTHEAST AS RADAR RETURNS ARE DIMINISHING QUICKLY IN THE AREA. OTHERWISE CURRENT FORECAST LOOKS TO BE ON TRACK. UPDATE ISSUED AT 948 PM CDT THU MAY 8 2014 RAIN EXITING THE CENTRAL SECTION OF THE STATE AND NOW PRIMARILY IN THE JAMES RIVER VALLEY. TRIMMED POPS CENTRAL. OTHERWISE SO FAR CURRENT FORECAST LOOKS GOOD. UPDATE ISSUED AT 655 PM CDT THU MAY 8 2014 AT 630 PM CDT...SATELLITE LOOPS SHOW HIGH CLOUDS SPREADING OVER SOUTHWEST NORTH DAKOTA REPOPULATING THE CLEAR AREA. H300 CLOSED LOW ON THE RAP MODEL SUGGESTS CIRCULATION AROUND THIS FEATURE IN NORTHEAST WYOMING LIKELY HELPING TO SPREAD THESE HIGH CLOUDS OVER SOUTHWEST ND. MEANWHILE...H500 LOW MIGRATING THROUGH NORTHEAST SOUTH DAKOTA INTO SOUTHEAST NORTH DAKOTA. LIKE THE CURRENT POPS AND WILL NOT CHANGE AT THIS TIME. MAINLY CLOUDS. MAY BE ABLE TO DROP POPS CENTRAL AFTER 9 PM. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 339 PM CDT THU MAY 8 2014 RAINFALL ENDING THIS EVENING AND A DRY FRIDAY WILL HIGHLIGHT THE SHORT TERM. RAINFALL THE REMAINDER OF THE AFTERNOON IS EXPECTED TO REMAIN ALONG AND EAST OF A LINE FROM SELFRIDGE...THROUGH BISMARCK AND HARVEY...SLOWLY DECREASING FROM WEST TO EAST. BASED UPON THE 17-19 UTC RAP/HRRR...RAIN SHOULD FINALLY END ACROSS THE JAMES RIVER VALLEY BY 06-07 UTC. OTHERWISE FOR TONIGHT...A WEAK SURFACE RIDGE AXIS WILL BE IN PLACE ACROSS WESTERN AND CENTRAL NORTH DAKOTA. GIVEN CLEAR SKIES...LIGHT WINDS AND DEW POINTS IN THE UPPER TEENS AND 20S...WIDESPREAD OVERNIGHT LOWS IN THE 20S ARE FORECAST OUTSIDE OF THE JAMES RIVER VALLEY WHERE GREATER CLOUD COVER AND MOISTURE WILL KEEP LOWS IN THE 30S. LEFT THE MENTION OF FOG OUT FOR NOW DUE TO DECEASING LOW LEVEL MOISTURE PROFILES WITH HEIGHT AND THE GREATER LIKELIHOOD OF FROST COMPARED TO FOG. FRIDAY WILL BE CLEAR AND DRY WITH HIGHS IN THE 60S WITH SOUTHERLY FLOW AHEAD OF THE SURFACE LOW ACROSS EASTERN MONTANA. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 339 PM CDT THU MAY 8 2014 AN ACTIVE AND COOL WEATHER PATTERN DEVELOPS FOR THE UPCOMING WEEKEND. UNCERTAINTY INCREASES AFTERWARDS WHEN COMPARING THE LATEST FEW RUNS OF THE GFS AND ECMWF. UPPER LOW/TROUGH OVER THE PACIFIC NORTHWEST DIGS ACROSS THE WESTERN CONUS FRIDAY NIGHT INTO SATURDAY...MOVING OVER THE ROCKIES SUNDAY. 12Z GFS IS MORE PROGRESSIVE AND MOVES THE TROUGH EAST BY MONDAY NIGHT...WHILE THE 00Z/12Z ECMWF LINGERS THE TROUGH THROUGH TUESDAY. NORTHWEST FLOW IS ADVERTISED BY BOTH MODELS BEHIND THE TROUGH...LIKELY ACTIVE WITH EMBEDDED WAVES MOVING THROUGH THE REGION. BASICALLY HAVE CHANCES FOR PRECIPITATION THROUGH THE PERIOD ALONG WITH CONTINUED COOL/BELOW AVERAGE TEMPERATURES. BEST CHANCES FOR PRECIPITATION WILL BE OVER THE WEEKEND AS SFC LOW PRESSURE AND LEAD WAVES MOVE ACROSS THE DAKOTAS. MIX OF RAIN/SNOW POSSIBLE WEST SUNDAY MORNING AS COLDER AIR IS PULLED SOUTH FROM CANADA. ADDITIONAL SNOW POSSIBLE EARLY NEXT WEEK IF THE EUROPEAN`S SOLUTION IS CORRECT WITH A SLOWER EASTWARD PROGRESSION ALLOWING FOR ANOTHER SHOT OF COLD AIR INTO THE REGION. MODELS PORTRAY NO INDICATION OUR COOL AND WET PATTERN WILL CHANGE THROUGH AT LEAST MID-MAY...AND POSSIBLY NOT UNTIL AFTER THE THIRD WEEK OF MAY AT THE EARLIEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1259 AM CDT FRI MAY 9 2014 VFR CONDITIONS EXPECTED ACROSS ALL TERMINALS THROUGH THE 06 UTC TAF PERIOD. MID CLOUD DECK WILL MOVE EAST OF KJMS AROUND 12 UTC TONIGHT. WINDS WILL MAINLY BE LIGHT AND VARIABLE TONIGHT...EXCEPT AT KJMS...AND GRADUALLY BECOME SOUTHERLY THROUGH THE DAY FRIDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MM SHORT TERM...AYD LONG TERM...NH AVIATION...MM
AREA FORECAST DISCUSSION
NWS TULSA OK
1156 PM CDT THU MAY 8 2014 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. MVFR CEILINGS WILL BE PREVALENT OVERNIGHT INTO FRIDAY MORNING...WITH SOME IFR CEILINGS POSSIBLE AT TIMES...ESPECIALLY AT KMLC. SCATTERED SHOWERS AND THUNDERSTORMS IN NORTHEAST OKLAHOMA WILL BE MOST LIKELY TO AFFECT KBVO FOR THE FIRST FEW HOURS OF THE FORECAST PERIOD. CONDITIONS WILL BECOME VFR AT ALL SITES BY FRIDAY AFTERNOON. && .PREV DISCUSSION... /ISSUED 858 PM CDT THU MAY 8 2014/ DISCUSSION... DRYLINE/FRONTAL STORMS BEGINNING TO PUSH EASTWARD INTO WESTERN OSAGE COUNTY AT THIS TIME. BOTH THE HRRR AND THE LOCAL WRF INDICATE ADDITIONAL DEVELOPMENT POTENTIAL PRIMARILY ALONG THE KANSAS BORDER OVERNIGHT. SOME SEVERE THREAT WILL EXIST...BUT LIMITED INSTABILITY FARTHER EAST WILL START TO LIMIT THE OVERALL THREAT SOMEWHAT AS THE NIGHT GOES ON. TRENDS ON THE AFOREMENTIONED STORMS ALREADY SHOWING THIS TO SOME EXTENT. OVER SOUTHEAST OKLAHOMA AND WESTERN ARKANSAS...ONGOING PRECIP WILL CONTINUE TO SHIFT EAST OF THE AREA...WITH PRECIP CHANCES DECREASING ESPECIALLY AFTER MIDNIGHT. THIS WILL ALSO DIMINISH ANY FLOOD THREAT THAT EXISTS. ADDITIONAL TWEAKS TO POP GRIDS WILL LIKELY BE FORTHCOMING...ESPECIALLY FOR POST 06Z TIME FRAME. TEMPERATURE WISE...WITH CLOUDS REMAINING THROUGH MOST OF THE NIGHT...LOWS WILL REMAIN RELATIVELY WARM...IN THE 60S FOR MOST OF THE AREA. PREV DISCUSSION... /ISSUED 638 PM CDT THU MAY 8 2014/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. CEILINGS WILL BECOME MVFR AT ALL LOCATIONS OVERNIGHT. AN ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE...ESPECIALLY AT THE NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS SITES...BUT THE CHANCES ARE TOO LOW TO INCLUDE IN THE TAFS. CONDITIONS WILL IMPROVE TO VFR BY FRIDAY AFTERNOON AND WINDS WILL BECOME LIGHT AS A WEAK FRONTAL BOUNDARY ACROSS THE AREA BEGINS TO WASH OUT. PREV DISCUSSION... /ISSUED 302 PM CDT THU MAY 8 2014/ DISCUSSION... A LARGE AREA OF RAINFALL WITH EMBEDDED THUNDERSTORMS CONTINUES TO MOVE EASTWARD ACROSS THE CWA THIS AFTERNOON AHEAD OF AN UPPER TROUGH TRAVERSING THE SOUTHERN PLAINS. THE PRECIPITATION IS ENDING FROM WEST TO EAST ACROSS MUCH OF NORTHEAST OKLAHOMA WITH SOME CLEARING BEHIND THAT. THE DRYLINE REMAINS TO OUR WEST AND A COLD FRONT REMAINS TO OUR NORTH. THIS SCENARIO SHOULD BE CONDUCIVE FOR STORMS TO REDEVELOP LATE THIS AFTERNOON AND EVENING IN NORTHEAST OKLAHOMA AND POSSIBLY INTO NORTHWEST ARKANSAS. AFTER TONIGHT... THUNDERSTORM CHANCES WILL EASE BACK FOR A COUPLE OF DAYS AS UPPER FLOW BRIEFLY BECOMES ZONAL. ANOTHER UPPER TROUGH DEVELOPING TO OUR WEST WILL MOVE ACROSS THE AREA SUNDAY INTO MONDAY. A COLD FRONT ACCOMPANYING THIS SYSTEM WILL SWEEP ACROSS THE CWA BEGINNING EARLY MONDAY MORNING. THUNDERSTORM CHANCES WILL INCREASE ALONG AND AHEAD OF THE FRONT. SEVERE STORMS MAY BE POSSIBLE EVEN THOUGH THE TIMING OF FRONTAL PASSAGE IS DISADVANTAGEOUS. FOR THE REMAINDER OF NEXT WEEK... MILD CONDITIONS WILL PREVAIL. PRECIPITATION CHANCES WILL BE MINIMAL WITH TEMPERATURES SLIGHTLY BELOW SEASONAL AVERAGES. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...05
AREA FORECAST DISCUSSION
NWS TULSA OK
858 PM CDT THU MAY 8 2014 .DISCUSSION... DRYLINE/FRONTAL STORMS BEGINNING TO PUSH EASTWARD INTO WESTERN OSAGE COUNTY AT THIS TIME. BOTH THE HRRR AND THE LOCAL WRF INDICATE ADDITIONAL DEVELOPMENT POTENTIAL PRIMARILY ALONG THE KANSAS BORDER OVERNIGHT. SOME SEVERE THREAT WILL EXIST...BUT LIMITED INSTABILITY FARTHER EAST WILL START TO LIMIT THE OVERALL THREAT SOMEWHAT AS THE NIGHT GOES ON. TRENDS ON THE AFOREMENTIONED STORMS ALREADY SHOWING THIS TO SOME EXTENT. OVER SOUTHEAST OKLAHOMA AND WESTERN ARKANSAS...ONGOING PRECIP WILL CONTINUE TO SHIFT EAST OF THE AREA...WITH PRECIP CHANCES DECREASING ESPECIALLY AFTER MIDNIGHT. THIS WILL ALSO DIMINISH ANY FLOOD THREAT THAT EXISTS. ADDITIONAL TWEAKS TO POP GRIDS WILL LIKELY BE FORTHCOMING...ESPECIALLY FOR POST 06Z TIME FRAME. TEMPERATURE WISE...WITH CLOUDS REMAINING THROUGH MOST OF THE NIGHT...LOWS WILL REMAIN RELATIVELY WARM...IN THE 60S FOR MOST OF THE AREA. && .PREV DISCUSSION... /ISSUED 638 PM CDT THU MAY 8 2014/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. CEILINGS WILL BECOME MVFR AT ALL LOCATIONS OVERNIGHT. AN ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE...ESPECIALLY AT THE NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS SITES...BUT THE CHANCES ARE TOO LOW TO INCLUDE IN THE TAFS. CONDITIONS WILL IMPROVE TO VFR BY FRIDAY AFTERNOON AND WINDS WILL BECOME LIGHT AS A WEAK FRONTAL BOUNDARY ACROSS THE AREA BEGINS TO WASH OUT. PREV DISCUSSION... /ISSUED 302 PM CDT THU MAY 8 2014/ DISCUSSION... A LARGE AREA OF RAINFALL WITH EMBEDDED THUNDERSTORMS CONTINUES TO MOVE EASTWARD ACROSS THE CWA THIS AFTERNOON AHEAD OF AN UPPER TROUGH TRAVERSING THE SOUTHERN PLAINS. THE PRECIPITATION IS ENDING FROM WEST TO EAST ACROSS MUCH OF NORTHEAST OKLAHOMA WITH SOME CLEARING BEHIND THAT. THE DRYLINE REMAINS TO OUR WEST AND A COLD FRONT REMAINS TO OUR NORTH. THIS SCENARIO SHOULD BE CONDUCIVE FOR STORMS TO REDEVELOP LATE THIS AFTERNOON AND EVENING IN NORTHEAST OKLAHOMA AND POSSIBLY INTO NORTHWEST ARKANSAS. AFTER TONIGHT... THUNDERSTORM CHANCES WILL EASE BACK FOR A COUPLE OF DAYS AS UPPER FLOW BRIEFLY BECOMES ZONAL. ANOTHER UPPER TROUGH DEVELOPING TO OUR WEST WILL MOVE ACROSS THE AREA SUNDAY INTO MONDAY. A COLD FRONT ACCOMPANYING THIS SYSTEM WILL SWEEP ACROSS THE CWA BEGINNING EARLY MONDAY MORNING. THUNDERSTORM CHANCES WILL INCREASE ALONG AND AHEAD OF THE FRONT. SEVERE STORMS MAY BE POSSIBLE EVEN THOUGH THE TIMING OF FRONTAL PASSAGE IS DISADVANTAGEOUS. FOR THE REMAINDER OF NEXT WEEK... MILD CONDITIONS WILL PREVAIL. PRECIPITATION CHANCES WILL BE MINIMAL WITH TEMPERATURES SLIGHTLY BELOW SEASONAL AVERAGES. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...22
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
333 AM CDT FRI MAY 9 2014 .DISCUSSION... AT 06Z...THERE WAS A WEAK AREA OF LOW PRESSURE OVER CENTRAL OKLAHOMA AND ANOTHER WEAK AREA OF LOW PRESSURE NORTH OF DEL RIO. SFC DEW PTS REMAIN IN THE LOWER 70S. RADAR IS A LITTLE MORE ACTIVE THAN THE PAST FEW NIGHTS WITH A LINE OF STORMS DEVELOPING ACROSS EXTREME SE TX FROM KBPT TO KGLS AND A SMALL CLUSTER NEAR KGRK. WATER VAPOR IMAGERY SHOWS A WELL DEFINED S/WV IN EASTERN NEW MEXICO AND THIS FEATURE WAS MOVING EAST AND WILL SERVE AS A CATALYST FOR SHRA/TSRA OVER PARTS OF CENTRAL AND EASTERN TEXAS TODAY. THE DISTURBANCE WILL APPROACH SE TX THIS AFTN AND FEEL IT WILL TRIGGER TSRA OVER MAINLY THE WESTERN HALF OF THE CWA. NAM 12 SOUNDING FOR KCLL ARE VERY UNSTABLE WITH PWATS INCREASING FROM 1.38 THIS MORNING TO 1.79 THIS AFTN. CAPE VALUES EXCEED 3000 J/KG AND LI`S DROP TO -9. SPC HAS OUTLOOKED THE WESTERN HALF OF SE TX IN SLIGHT RISK AND SEE NO REASON TO DISAGREE. THE NAM...GFS AND ECMWF ALL SHOW A SPEED MAX APPROACHING THIS AFTERNOON SO IT LOOKS LIKE ALL THE INGREDIENTS ARE IN PLACE FOR SOME SEVERE WEATHER OVER THE WESTERN ZONES. TOWARD THE HOUSTON AREA AND THE COAST...CAPPING LOOKS TO REMAIN AN ISSUE AND PWATS ACTUALLY DROP THIS AFTN. WILL MAINTAIN LOW END CHANCE POPS BUT SOUNDINGS LOOK MUCH LESS FAVORABLE. THINGS SHOULD SETTLE DOWN QUICKLY TONIGHT WITH THE LOSS OF HEATING. FWIW...THE HRRR INITIALIZED BEST THIS MORNING AND HAVE LEANED TOWARD THIS SOLUTION FOR THE SHORT TERM. VERY WARM AND HUMID CONDITIONS ARE EXPECTED OVER THE WEEKEND. CAN`T RULE OUT ISOLATED SHOWERS WITH HEATING EACH DAY. PWATS REMAIN AROUND 1.5-1.6 INCHES SO WILL MENTION A SLIGHT CHANCE OF SHRAS EACH DAY. THINGS BECOME A LITTLE MORE MUDDLED MON-WED. A DEEP UPPER LEVEL TROUGH AND SURFACE COLD FRONT WILL APPROACH THE STATE ON MONDAY. MODELS ARE IN GOOD AGREEMENT THROUGH MONDAY 12Z BUT DIVERGE SIGNIFICANTLY THEREAFTER. GFS IS ABOUT 24-30 HOURS FASTER THAN THE ECMWF. THE CANADIAN SUPPORTS THE SLOWER ECMWF. NOT REALLY SURE HOW THINGS WILL EVENTUALLY TRANSPIRE THIS FAR OUT SO HAVE STARTED POPS ON MONDAY AND WILL CARRY POPS THROUGH WEDNESDAY. AT THE CURRENT TIME...FEEL TUESDAY WILL BE THE BEST DAY FOR RAIN CHANCES BUT THAT IS SUBJECT TO CHANGE. HAVE RAISED RAIN CHANCES ON TUESDAY TO 50 PERCENT. CONSIDERABLY COOLER AND DRIER CONDITIONS WILL DEVELOP IN THE WAKE OF THE FRONT FOR THE SECOND HALF OF NEXT WEEK WITH MIN TEMPS POSSIBLY FALLING BACK INTO THE 50S. 43 && .MARINE... ONSHORE WINDS ARE EXPECTED THROUGH THE WEEKEND. WIND SPEEDS WILL BE HIGH ENOUGH THIS MORNING FOR CAUTION CONDITIONS. MODERATE TO STRONG ONSHORE WINDS ARE THEN EXPECTED TO DEVELOP SUNDAY NIGHT AS LOW PRESSURE DEVELOPS OVER THE PLAINS. THE MODELS THEN DIFFERED ON THE PASSAGE OF A COLD FRONT THROUGH SE TX AND OFF THE COAST. LIKED THE SLOWER ECMWF. 40 .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 86 69 88 71 88 / 50 30 10 10 10 HOUSTON (IAH) 86 71 87 73 87 / 30 20 20 10 20 GALVESTON (GLS) 81 73 82 73 82 / 30 20 20 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 5 AM CDT EARLY THIS MORNING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT THU MAY 8 2014 .UPDATE... ISSUED AT 1021 PM CDT THU MAY 8 2014 ONE LAST BATCH OF SHOWERS AND THUNDERSTORMS ARE MOVING ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. 0-3KM/MLCAPE HAS BEEN DROPPING OVER THE PAST FEW HOURS AND EXPECT THAT TREND TO CONTINUE THROUGH THE REST OF THE NIGHT. BASED ON 09.01Z RAP ANALYSIS...IT ALSO APPEARS THAT THESE STORMS ARE OCCURRING IN A RELATIVE MINIMUM OF 0-6KM SHEAR AS WELL. THUS...EXPECT THAT STORMS SHOULD REMAIN SUB-SEVERE FROM HERE ON OUT THROUGH THE REST OF TONIGHT. TEMPERATURES WILL REMAIN MILD IN THE UPPER 60S UNTIL THE COLD FRONT PUSHES THROUGH TOWARD DAYBREAK WITH CONVECTION NOT EXPECTED ALONG THIS FRONT. && .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT) ISSUED AT 241 PM CDT THU MAY 8 2014 MAIN FORECAST CONCERNS THIS PERIOD...SHRA/TSRA/SEVERE CHANCES THRU THIS EVENING...LINGERING -SHRA CHANCES FRI...TEMPERATURES. 18Z DATA ANALYSIS HAD A 1000MB LOW OVER NORTHEAST NEB WITH A TROUGH NORTHEAST INTO NORTHWEST WI AND WARM FRONT ARCING EAST ACROSS NORTHERN IA INTO SOUTHERN WI. WARM FRONT CONTINUES TO SEPARATE TO DISTINCT AIRMASSES...70S WITH DEW POINTS IN THE 60S SOUTH OF THE WARM FRONT...60S WITH DEW POINTS IN THE 50S. SB CAPE SOUTH OF THE FRONT IN THE 1500-2500 J/KG RANGE...ELEVATED 500-1000 J/KG NORTH OF THE WARM FRONT. AREA WSR-88D/S SHOWING CONVECTION DEVELOPING/ EXPANDING ACROSS THE SOUTH HALF OF IA...WITH/AHEAD OF SHORTWAVE ENERGY LIFTING UP THE EAST SIDE OF THE MID LEVEL LONG WAVE TROUGH. 08.12Z MODELS GENERALLY INITIALIZED WELL. GFS AGAIN ABOUT 5F HIGH WITH SFC DEW POINTS IN THE MOISTURE PLUME COMING NORTH THRU THE MID MS VALLEY. SOLUTIONS CONVERGING ON A TIGHT COMPROMISE CONSENSUS OF THE EARLIER RUNS AS THE TROUGHING/ENERGY OVER THE ROCKIES/PLAINS LIFTS NORTHEAST THRU THE UPPER MIDWEST TONIGHT THRU FRI NIGHT. STILL SOME LOWER LEVEL DETAIL DIFFERENCES ON CONVECTION EVOLUTION THRU THIS EVENING...BUT AFTER THAT SOLUTIONS QUITE SIMILAR FOR LATER TONIGHT THRU FRI NIGHT AS COOLER/DRIER AIR SPREADS IN BEHIND THE PASSING LOW/COLD FRONT. FCST CONFIDENCE GENERALLY GOOD FOR TONIGHT THRU FRI NIGHT. FOR THE SHORT TERM...AS OF EARLY THIS AFTERNOON...CONVECTIVE SCENARIO FOR LATER THIS AFTERNOON/THIS EVENING REMAINS IN QUESTION. MAIN FOCUS FOR TSRA DEVELOPMENT REMAINS WESTERN IA/SOUTHWEST MN...NEAR THE SFC LOW/TROUGH/FRONTS AND CLOSER TO THE STRONGER SHORTWAVE LIFTING TOWARD EASTERN SD. SHRA/TSRA DEVELOPING/SPREADING NORTH ACROSS IA...ALONG WITH THE CLOUD COVER CONSUMING/LIMITING CAPE EARLY THIS AFTERNOON AND MUDDYING THE TSRA/SEVERE EVOLUTION FOR LATER THIS AFTERNOON/EVENING. LOWER LEVEL CONVERGENCE/FORCING WOULD POINT TO A LINE OF STRONG/SEVERE TSRA DEVELOPING IN WESTERN IA/SOUTHWEST MN THEN LIFTING NORTHEAST ACROSS MN/IA/WI IN THE 21Z-04Z TIME-FRAME. STRONGEST 0-6KM BULK SHEAR OF 30-60KTS IS OVER THE WEST PORTIONS OF THE FCST AREA THIS AFTERNOON AND NORTHWEST PORTIONS OF THE FCST AREA THIS EVENING. SWODY1 SEEMS TO HAVE THE THREATS/RISKS LAYED OUT WELL...BASED ON CONVECTION LIFTING NORTH ACROSS IA NOT INTERFERING TOO MUCH. WILL STAY THE COURSE WITH HIGHEST SHRA/TSRA CHANCES LATER THIS AFTERNOON/EVENING WITH WHAT SHOULD BE A LINE OF CONVECTION MOVING EAST/NORTHEAST ACROSS THE FCST AREA WITH/AHEAD OF THE SFC- 850MB TROUGH/COLD FRONT. SEE SWODY1 FOR MORE DETAILS ON THE SEVERE THREATS THRU THIS EVENING. 925-850MB COLD ADVECTION/DRYING SPREAD RATHER QUICKLY ACROSS THE FCST AREA LATE THIS EVENING/OVERNIGHT AS THE SFC-850MB LOW LIFTS INTO NORTHEAST MN. PW VALUES OF 1 TO 1.5 INCHES AT 00Z FRI ARE HALF THAT BY 12Z FRI. THIS AND PASSAGE OF THE SFC-850MB TROUGH/FRONT SWEEP THE BULK OF THE SHRA/TSRA EAST AND OUT OF THE FCST AREA BY 12Z FRI. ONLY SOME SMALL LINGERING -SHRA CHANCES IN THE EAST/NORTH ENDS OF THE FCST AREA BY 12Z FRI. A SECONDARY SHORTWAVE TO LIFT ACROSS THE AREA FRI AFTERNOON ALONG WITH SOME 850-700MB WRAP-AROUND/ DEFORMATION BAND MOISTURE. DEEPEST OF THIS MOISTURE ACROSS THE NORTH END OF THE FCST AREA...WITH STEEP LOW LEVEL LAPSE RATES AND WEAK INSTABILITY TO ABOUT 750MB. CONTINUED THE SMALL -SHRA CHANCES ACROSS MAINLY THE NORTHEAST 1/3 OF THE FCST AREA THRU FRI AFTERNOON...WHICH BLENDS WELL WITH NEIGHBORING GRIDS. LOSS OF DIURNAL HEATING AND PASSING OF THE SECOND SHORTWAVE QUICKLY PUTS AN END TO THIS AND LEFT FRI NIGHT DRY AS HIGH PRESSURE AND SHORTWAVE RIDGING ALOFT BUILD INTO THE REGION. A COOLER PERIOD TONIGHT THRU FRI NIGHT AS A COOL 925MB AIRMASS SETTLES OVER THE REGION. WINDS/CLOUDS TO KEEP LOWS TONIGHT ABOVE NORMAL. BELOW NORMAL HIGHS FRI UNDER THE COOL 925MB AIRMASS. BELOW NORMAL LOWS FRI NIGHT UNDER MOSTLY CLEAR SKIES/LIGHT WINDS. USED THE MODEL/ENSEMBLE CONSENSUS LOWS/HIGHS FOR TONIGHT THRU FRI NIGHT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 241 PM CDT THU MAY 8 2014 MAIN FORECAST CONCERNS FOR SAT THRU SUN NIGHT...SHRA/TSRA CHANCES THRU THE PERIOD AS MORE TROUGHING/SHORTWAVES TAKE AIM AT THE UPPER MIDWEST. DECENT AGREEMENT AMONG THE 08.12Z MODELS CONTINUES SAT AS THE NEXT STRONGER SHORTWAVE TRACKS INTO MN BY LATE IN THE DAY. IMPROVING CONSENSUS FOR RISING HGTS/SHORTWAVE RIDGING TO BUILD ACROSS THE UPPER MIDWEST LATER SAT/SAT NIGHT...AHEAD OF THE NEXT STRONG/LONG WAVE TROUGH TO DIG INTO THE WESTERN CONUS. TREND CONTINUES STRONGER WITH THIS NEXT TROUGHING INTO THE ROCKIES SAT NIGHT/SUN THEN EJECTING INTO THE WESTERN PLAINS SUN NIGHT. SHORTWAVE RIDGE AXIS THAT BUILDS OVER THE REGION SAT NIGHT QUICKLY MOVES EAST SUN...WITH THE REGION ALREADY UNDER THE INFLUENCE OF SOUTHWEST FLOW ALOFT AHEAD OF THE NEXT TROUGH FOR SUN AFTERNOON/NIGHT. WITH RUN-TO-RUN CONSISTENCY AND THE IMPROVING CONSENSUS...SAT THRU SUN NIGHT FCST CONFIDENCE IS AVERAGE TO GOOD. BREAK BETWEEN SYSTEMS FRI NIGHT INTO SAT IS BRIEF. THE NEXT SHORTWAVE INTO MN LATER SAT QUICKLY SPREADS INCREASING LOWER LEVEL THERMO-DYNAMIC FORCING/LIFT AND INCREASING MOISTURE/THETA-E CONVERGENCE INTO THE FCST AREA THRU THE DAY ON SAT. INITIAL MOISTURE/LIFT GOES INTO SATURATION SAT MORNING...WITH INCREASING SHRA CHANCES INTO SAT AFTERNOON/EVENING AS THE DEEPEST MOISTURE/ STRONGER OF THE LIFT MOVES ACROSS. CARRIED HIGHEST RAIN CHANCES LATER SAT AFTERNOON/EVENING...THE LOWER LATER SAT NIGHT BEHIND THE SFC-850MB TROUGH AXIS. INDICATIONS FOR 250 TO AS MUCH AS 1K J/KG MU CAPE INTO THE AREA AT 00Z SUN SO CONTINUED TSRA MENTION FOR MUCH OF THE FCST AREA SAT AFTERNOON/EVENING. NEXT BREAK BETWEEN SYSTEMS IS ALSO RATHER BRIEF LATER SAT NIGHT/SUN MORNING. WITH THE PROGRESSIVE AND ACTIVE FLOW...THE UPPER MIDWEST IS BACK UNDER SOUTHWEST FLOW ALOFT SUN AFTERNOON/NIGHT...AHEAD OF STRONG MID LEVEL TROUGHING SWINGING THRU THE CENTRAL/SOUTHERN ROCKIES. INCREASING MOISTURE/ LIFT/INSTABILITY QUICKLY SPREAD BACK INTO THE FCST AREA FOR SUN AFTERNOON/NIGHT. PW VALUES IN THE 1 INCH PLUS RANGE BY 00Z MON... AHEAD OF THE NEXT STRONGER SHORTWAVE AND SFC-850MB LOW LIFTING NORTHEAST TOWARD/INTO THE UPPER MIDWEST SUN NIGHT. RAISED SHRA/TSRA CHANCES INTO THE 35-55 PERCENT RANGE SUN AFTERNOON AND 55-70 PERCENT RANGE SUN NIGHT. SOME LOCALLY HEAVY RAINS POSSIBLE SUN NIGHT... DEPENDING ON WHERE THE SFC LOW TRACKS/SFC BOUNDARIES SET UP. DUE TO SOME UNCERTAINTIES WITH WHAT WOULD BE TIMING OF SHRA/TSRA IN/AROUND THE AREA AND CLOUD COVER...USED THE MODEL/ENSEMBLE CONSENSUS HIGHS/ LOWS FOR SAT THRU SUN NIGHT. FOR MONDAY THROUGH THURSDAY.../DAYS 4 TO 7/... MAIN FORECAST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES/RAIN AMOUNTS MON/MON NIGHT...SHRA CHANCES/COOLER TEMPS TUE-THU. MEDIUM RANGE MODEL RUNS OF 08.00Z AND 08.12Z ALL SHOW THE SCENARIO OF STRONG TROUGHING MOVING INTO THE CENTRAL CONUS MON. GFS REMAINS FASTER THAN ECMWF/CAN-GEM. GOOD CONSENSUS FOR THE STRONG TROUGHING TO THEN VERY SLOWLY MOVE INTO/ACROSS THE MID/UPPER MS VALLEY TUE THRU THU...WITH CAN-GEM THE SLOWER/STRONGER OUTLIER BY WED. OVERALL TREND IS SLOWING AND STRONGER WITH THE MID CONUS TROUGHING NEXT WEEK. EVEN WITH SOME DIFFERENCES AMONG THE MODELS FOR MON-THU THE SENSIBLE WEATHER OUTCOMES ARE MORE SIMILAR THAN ONE WOULD USUALLY EXPECT. DAY 4-7 FCST CONFIDENCE IS AVERAGE WITH RAIN CHANCES THRU THE PERIOD BUT GOOD FOR BELOW NORMAL TEMPS FOR TUE-THU. EVEN WITH THE DIFFERENCES ON PROGRESSION OF THE LONG-WAVE TROUGH ON MON...GOOD CONSENSUS FOR A STRONG PIECE OF ENERGY TO BE LIFTING NORTHEAST ACROSS THE UPPER MIDWEST MON/MON NIGHT. RATHER STRONG SFC LOW PROGGED TO ACCOMPANY THIS SHORTWAVE NORTHEAST ACROSS THE REGION MON. WITH PW VALUES OF AN INCH OR MORE...SHRA/TSRA CHANCES IN THE 40-65 PERCENT RANGE MON/MON NIGHT LOOK GOOD. POTENTIAL FOR 1 TO 2 INCHES OF RAIN FROM LATER SUN NIGHT THRU MON NIGHT. COLDER AIR POURS IN FOR TUE THRU THU AS THE THE NORTHERN STREAM PORTION OF THE MID LEVEL TROUGH SETTLES INTO THE UPPER MIDWEST. 850MB TEMPS FALL TO A FEW DEGREES EITHER SIDE OF 0C FOR MUCH OF TUE- THU...SOME 1 TO 2 STANDARD DEVIATIONS BELOW NORMAL. AFTER MORE NORMAL EARLY MAY TEMPS THROUGH THE WEEKEND...TEMPS FOR TUE-THU TREND AROUND 10F BELOW NORMAL. WITH THIS COLD CORE OF AIR ALOFT... STEEP LOW-MID LEVEL LAPSE RATE AND SHORTWAVES ROTATING THRU THE TROUGH WITH ROUNDS OF INCREASED MOISTURE/FORCING...SMALL -SHRA CHANCES MUCH OF THE TUE-THU PERIOD REASONABLE FOR NOW. GIVEN THE TIMING/DETAIL UNCERTAINTIES...DID NOT STRAY MUCH FROM THE MODEL/ ENSEMBLE CONSENSUS HIGHS/LOWS AND RAIN CHANCES FOR DAYS 4-7. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1140 PM CDT THU MAY 8 2014 WITH MOST OF THE RAIN AND STORMS HAVING MOVED OFF TO THE EAST...THE MAIN FOCUS IS ON THE IFR CEILINGS LINGERING BEHIND THE COLD FRONT/SURFACE LOW. THIS COLD FRONT WILL MOVE THROUGH SHORTLY AFTER MIDNIGHT WITH WINDS COMING AROUND TO THE SOUTHWEST TO WEST. AS THEY DO...THE IFR DECK THAT IS CURRENTLY IN WESTERN MINNESOTA WILL MOVE EAST OVERNIGHT AND SIT OVER RST/LSE THROUGH MUCH OF THE MORNING. FORECAST SOUNDINGS SHOW SOME MIXING OCCURRING BY EARLY AFTERNOON AS DRIER AIR MOVES IN. && .HYDROLOGY... ISSUED AT 241 PM CDT THU MAY 8 2014 FLOODING CONTINUES ALONG THE MISSISSIPPI RIVER...WITH LOCATIONS CRESTING BETWEEN GENOA AND LANSING. SHOWERS AND THUNDERSTORMS TODAY WILL PRODUCE ANYWHERE FROM A HALF INCH TO ONE INCH OF RAIN. THIS WILL LIKELY SLOW THE FALL FOR LOCATIONS NORTH OF MCGREGOR...AND MAY INCREASE CRESTS SLIGHTLY SOUTH OF MCGREGOR. POTENTIAL FOR 1 TO 2 INCHES OF RAINFALL FROM LATE SUN NIGHT THRU MON EVENING. THIS COULD HAVE ADDITIONAL IMPACTS AND PRODUCE ADDITIONAL RISES ON AREA RIVERS ALREADY RUNNING HIGH FROM THE ABOVE AND MUCH ABOVE NORMAL RAINS OF APRIL. CHECK OUT THE LATEST HYDROLOGIC STATEMENTS FOR THE DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...RRS LONG TERM....RRS AVIATION...HALBACH HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1137 PM MDT THU MAY 8 2014 .UPDATE... ISSUED AT 833 PM MDT THU MAY 8 2014 LATEST RADAR LOOP WAS SHOWING SHOWERS CONTINUING TO FLARE UP ACROSS EXTREME SOUTHEAST WYOMING MAINLY ALONG AND EAST OF THE LARAMIE RANGE DUE TO A COOL DOME ALOFT AND UPSLOPE FLOW PROMOTING THE INSTABILITY. THE MODELS ARE CONTINUING TO ADVERTISE THIS DOME OF COOL AIR SHIFTING EAST OVERNIGHT WHICH SHOULD ALLOW FOR MORE SUBSIDENCE TO MOVE INTO SOUTHEAST WYOMING. HOWEVER...I AM A LITTLE LEARY ABOUT YANKING THE POPS COMPLETELY UNTIL 3AM...SINCE WE DO HAVE SOMEWHAT OF AN UPSLOPE COMPONENT. THE OTHER CONCERN WE HAVE TONIGHT IS THE FOG POTENTIAL WHERE THE SNOWFALL TOOK PLACE LAST NIGHT. SNOW/CLOUD DISCRIMINATOR PRODUCT FROM CIRA IS SHOWING THE BULK OF THE SNOW OCCURRED IN THE NORTHERN PANHANDLE WHICH LOOKS TO BE THE MOST FAVORABLE REGION FOR FOG DEVELOPING OVERNIGHT. THIS AREA IS ALSO BEGIN TO CLEAR OUT WITH SOME PATCHY FOG BEGINNING TO SHOW UP IN DAWES AND BOX BUTTE COUNTIES. HRRR ALSO SHOWS GOOD INDICATIONS OF THIS FOG PERSISTING THROUGH THE NIGHT. WE MAY ALSO HAVE TO WATCH THIS AREA FOR POTENTIAL FOG ADVISORY. OTHERWISE...CURRENT FORECAST APPEARS TO BE ON TRACK. UPDATE ISSUED AT 415 PM MDT THU MAY 8 2014 SENDING OUT A QUICK UPDATE TO INCREASE PRECIPITATION CHANCES ACROSS ALBANY...LARAMIE AND KIMBALL COUNTIES AS A BATCH OF RAIN AND EMBEDDED THUNDER MOVES EAST THROUGH THAT REGION. THE BULK OF THE CONVECTION SHOULD END AFTER SUNSET. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 330 PM MDT THU MAY 8 2014 SNOW HAS COME TO AN END ACROSS THE NORTHERN NE PANHANDLE THIS AFTN AS AN INTENSE SFC LOW AND ASSOCIATED MID LEVEL TROWAL HAVE EXITED THE AREA TO THE NORTHEAST. ONLY CONCERN IN THE NEAR TERM WILL BE THE POTENTIAL FOR CONVECTIVE ACTIVITY THROUGH THIS EVE. CLEARING SKIES ON THE BACK SIDE OF THE SYSTEM HAVE ALLOWED TEMPS TO WARM NICELY...INTO THE MIDDLE TO UPPER 40S ACROSS MUCH OF SOUTHEAST WY. MID LEVELS ARE QUITE COLD WITH LAPS SOUNDINGS SHOWING H5 TEMPS TO -20C...SO A GREAT SETUP FOR INSTABILITY RAIN SHOWERS. LATEST RADAR LOOP SHOWS THIS ACTIVITY CONFINED TO THE I80 CORRIDOR...AND BELIEVE THIS TREND WILL CONTINUE THROUGH THE EARLY EVE AS MESOSCALE MODELS SHOW LIFTED INDICES AROUND ZERO HERE. WE HAVE SEEN SOME LIGHTNING STRIKES ALONG THE CO BORDER IN THE PAST FEW HOURS...BUT MODEST CONVECTIVE INSTABILITY PROFILES SUGGEST MOST OF THIS ACTIVITY WILL BE OF THE SHOWER VARIETY. LARGE SCALE SUBSIDENCE WILL BUILD INTO THE AREA BY LATE EVE BENEATH WEAK SHORTWAVE RIDGING...ENDING THE THREAT FOR SHOWERS AND STORMS. NEXT CHANCE FOR CONVECTION WILL BE FRI AFTN AHEAD OF THE NEXT WEAK MID LEVEL SHORTWAVE EMBEDDED WITHIN ZONAL FLOW ALOFT. WENT AHEAD AND ADDED ISO THUNDER TO THE GRIDS AS THE LATEST GFS IS SHOWING 500 TO 750 J/KG OF SBCAPE. NAM BUFKIT SOUNDINGS SHOW SOME WEAK ELEVATED INSTABILITY AS WELL. NO CONCERNS FOR SEVERE WEATHER THOUGH. DESPITE SOME HIGH LEVEL CLOUD COVER LIKELY MOVING OVERHEAD WITH INCREASING 700-300 MILLIBAR MOISTURE...DOWNSLOPE WARMING SHOULD AID IN WIDESPREAD 60S FOR HIGHS EAST OF THE LARAMIE RANGE. MOST OF THE SNOW IN THE PANHANDLE SHOULD BE MELTED BY THEN...SO EXPECT A MINIMAL IMPACT TO TEMPS. ATTENTION THEN SHIFTS TO THE POTENTIAL FOR YET ANOTHER MAJOR STORM FOR THE WEEKEND. MODELS ARE IN GREAT AGREEMENT SHOWING A VIGOROUS UPPER-LEVEL TROUGH DIGGING INTO THE GREAT BASIN ON SAT. MOIST SOUTH WEST FLOW ALOFT AND A FEW DISTURBANCES EMANATING FROM THE PARENT TROUGH SUGGESTS ANOTHER GOOD CHANCE FOR SHOWERS AND STORMS...THOUGH WESTERLY LOW LEVEL FLOW SUGGESTS THE BULK OF THIS ACTIVITY WILL BE ALONG AND WEST OF THE LARAMIE RANGE. LIMITED MOISTURE SHOULD KEEP SEVERE WEATHER AT BAY THIS TIME AROUND...THOUGH SHEAR PROFILES WILL BE RATHER STRONG. GFS...NAM...AND ECMWF ALL SHOW A STRONG SFC COLD FRONT BLASTING SOUTH ACROSS THE CWA LATE SAT NIGHT. NORTH TO NORTH EAST SFC UPSLOPE FLOW AND LARGE SCALE VERTICAL ASCENT WILL ALMOST CERTAINLY FAVOR PCPN DEVELOPMENT...BUT THE BIG QUESTION NOW IS EXACTLY WHERE. THE GFS IS STILL THE OUTLIER WITH HEAVY PCPN BANDING FROM NORTH CENTRAL CO INTO THE SOUTHERN PANHANDLE...WHILE THE ECMWF AND GEM ARE MUCH FURTHER NORTH WITH THE FRONTOGENESIS BAND AND WOULD AFFECT A LARGER PART OF OUR CWA. REGARDLESS...H7 TEMPS FALL TO BETWEEN -8C AND -12C IN THE POST FROPA AIR MASS WITH 1000-500 MB THICKNESSES RANGING FROM 540 TO 549 DM FROM NORTHWEST TO SOUTHEAST AT 12Z SUN. THIS WOULD SUPPORT SNOW... AND A LOT OF IT IF MODELED QPF VALUES ARE ANYTHING CLOSE TO WHAT ACTUALLY TRANSPIRES. IT IS A LITTLE UNSETTLING THAT THE ECMWF HAS BEEN CONSISTENT OVER THE LAST COUPLE OF RUNS WITH THE PLACEMENT OF THE HEAVIEST SNOW. IT WAS ALSO THE FIRST TO LOCK ON TO THIS PARTICULAR STORM EVOLUTION. IT IS MUCH TOO EARLY FOR ANY SORT OF HEADLINE...BUT CONFIDENCE IS HIGH THAT A PORTION OF OUR CWA WILL SEE SIGNIFICANT WINTER WEATHER. WENT AHEAD AND ISSUED A SPECIAL WEATHER STATEMENT HIGHLIGHTING THE POTENTIAL STORM FOR PUBLIC AWARENESS. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 330 PM MDT THU MAY 8 2014 FORECAST CHALLENGES EARLY IN THE EXTENDED PERIOD WILL FOCUS ON THE SPRING STORM SYSTEM MOVING ACROSS THE CENTRAL ROCKIES AND PLAINS. THERE ARE TIMING...STRENGTH AND POSITION DIFFERENCES WITH EMERGENCE OF THE UPPER LOW FROM THE CENTRAL GREAT BASIN SUNDAY. THE GFS IS TRENDING SLIGHTLY FASTER AND NORTH OF THE ECMWF. AT 12Z SUNDAY...GFS PROGS THE 554DM LOW OVER EAST CENTRAL UT...WHILE THE ECMWF/S 550DM LOW IS SITUATED IN SOUTHWEST UT. THE PRIMARY SURFACE LOW SHOWN BY THE GFS AT THE SAME TIME IS OVER FAR SOUTHWEST CO AND THE ECMWF/S LOW IS ALONG THE AZ/UT BORDER. BY 00Z MONDAY...GFS 559DM LOW IS OVER FAR WESTERN CO AND THE ECWMF 554DM LOW IS OVER SOUTH CENTRAL UT. THE SURFACE LOW REDEVELOPS AND INTENSIFIES OVER THE NORTHERN TX PANHANDLE IN THE GFS...AND SOUTHWEST CORNER OF KS IN THE ECMWF. THE 1000-500MB THICKNESS GRADIENT RAPIDLY TIGHTENS AND INTENSE LOW/MID LEVEL ASCENT DEVELOPS. COLD AIR AT LOW LEVELS WILL BE ADVECTED SOUTH INTO THE STORM SYSTEM ALONG THE EASTERN SLOPES OF THE ROCKIES...LOWERING SNOW LEVELS SIGNIFICANTLY. PLENTY OF MOISTURE WRAPPING INTO THE LOW...MID LEVEL QG FORCING AND LOW LEVEL UPSLOPE WILL RESULT IN SIGNIFICANT PRECIPITATION....WITH SNOW LEVELS POSSIBLY DROPPING AS LOW AS 4500 FT. A CONSENSUS OF THE GFS AND ECMWF QPF FROM 00Z SUNDAY THROUGH 12Z MONDAY INDICATES BETWEEN 1.5 AND 2.5 INCHES OF LIQUID PRECIPITATION. CONSENSUS MODEL SNOW ACCUMULATIONS PROJECT BETWEEN 12 AND 20 INCHES FOR THE MOUNTAINS... 4 TO 10 INCHES LOWER ELEVATIONS ALONG AND SOUTH OF I-80...AND 1 TO 4 INCHES NORTH OF I-80. STILL PLENTY OF UNCERTAINTY WITH THIS STORM AND WILL CONTINUE TO EVALUATE TRENDS AS THE STRENGTH AND TRACK OF THE STORM SYSTEM CAN CHANGE FROM ONE MODEL RUN TO THE NEXT. IT WILL BE MUCH COLDER SUNDAY AS 700MB TEMPERATURES FALL TO -5C TO -10C. HIGH TEMPERATURES SUNDAY WILL RANGE FROM THE 20S MOUNTAINS TO THE 40S OVER THE PLAINS. THESE TEMPERATURES MAY BE NEED TO BE LOWERED WITH LATER FORECASTS. GUSTY NORTHEAST WINDS OF 20 TO 30 MPH WILL ADD TO THE CHILL. IF YOU BELIEVE THE GFS...SNOW WILL BEGIN TO TAPER OFF FROM WEST TO EAST MONDAY MORNING. THE ECMWF KEEPS THE UPPER TROUGH AXIS ALONG THE FRONT RANGE WHICH WOULD PROLONG THE PRECIPITATION INTO MONDAY NIGHT. NORTHWEST FLOW ALOFT WILL PREVAIL TUESDAY THROUGH THURSDAY. THERE ARE INDICATIONS THAT IT WILL NOT BE DRY STABLE FLOW AS THERE WILL BE SOME MINOR DISTURBANCES WHICH MAY GENERATE SHOWERY EPISODES. TEMPERATURES MODERATE TOWARD SEASONAL NORMALS BY THE END OF THE PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING) ISSUED AT 1115 PM MDT THU MAY 8 2014 MAINLY VFR ACROSS THE AREA TONIGHT BUT SOME LOCAL LOW CLOUDS AND FOG WILL PRODUCE IFR. AFTER SUNRISE FOG AND LOW CLOUDS WILL DISSIPATE. WINDS WILL MAINLY BE ON THE LIGHT SIDE TONIGHT THROUGH FRIDAY. SCATTERED SHOWERS AND ISOLATED WEAK THUNDERSTORMS WEST OF THE LARAMIE RANGE FRIDAY AFTERNOON WITH ISOLATED SHOWERS AND THUNDERSTORMS TO THE EAST OF THE LARAMIE RANGE. && .FIRE WEATHER... ISSUED AT 300 PM MDT THU MAY 8 2014 NO FIRE WEATHER CONCERNS. MILD CONDITIONS ARE EXPECTED FOR FRIDAY AND SATURDAY...BUT WINDS AND RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN WELL OUTSIDE OF CRITICAL THRESHOLDS. ANOTHER SPRING STORM WILL AFFECT THE AREA SUNDAY AND MONDAY...BRINGING COOLER TEMPERATURES AND WIDESPREAD RAIN AND SNOW. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...REC SHORT TERM...HAMMER LONG TERM...JAMSKI AVIATION...SML FIRE WEATHER...HAMMER
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1123 AM EDT Fri May 9 2014 .Near Term [This Afternoon Through Tonight]... There is higher than normal uncertainty in the forecast from late this afternoon into tonight. Model guidance continues to indicate an area of heavy rainfall somewhere along the northern Gulf coast in that time period - with a sharp cutoff on the eastern extent. In other words, the models all generally agree that there will be a considerable gradient in rainfall somewhere in the vicinity of the western border of our forecast area. However, there is some variation in the exact placement of this gradient on the order of about 50-70 miles which makes a huge difference in impacts for our area. In general, global models have kept much of the rain west of our area through 12Z Saturday while a fair number of 4km WRF runs push the heavy rain into far western parts of our area (generally along and west of a PAM-DHN line). Models seem to be struggling to initialize a well-defined outflow boundary and other mesoscale features across western Alabama and Mississippi. When compared with recent objective analysis, the models seem to be placing these features a bit too far west. This argues that the surface and boundary layer foci for additional convective development this afternoon will be situated a bit closer to our local area. However, the large scale forcing mechanisms - including the LLJ and favored RFQ of the upper level jet streak - continue to be further west closer to what the models are portraying. Therefore, there is some uncertainty as to how to correct for the misplacement of these mesoscale features in the models, as large scale forcing mechanisms seem to be modeled fairly well. It may not be a simple linear adjustment (shifting the model QPF east 50 miles or so), given the lagging UVV aloft. The 14Z RAP analysis suggested that the boundary layer behind the outflow boundary over much of MS and W AL had been convectively overturned with MUCAPE less than 250 j/kg. Therefore, it seems that most of the new convective development would be focused in the warm, moist air mass just ahead of the outflow boundary this afternoon - or just west of our area. There is some evidence of this happening already on radar mosaics. This may put heavy rain and thunderstorms in a better position to push into our area tonight. However, given the high level of uncertainty, and only a handful of convection-allowing models showing high QPF in our area, we have opted not to issue a Flash Flood Watch at this time. We did bump up PoPs and QPF in the far western parts of our forecast area with this update, and will re-evaluate a watch this afternoon after new model guidance arrives. && .Hydrology... The only rivers that remain above flood stage at this time are the Choctawhatchee River at Bruce and several sites along the Suwannee River and stages are falling at all these locations. There is a chance of some heavy rainfall tonight and early Saturday in the far western part of our area - mainly in the Choctawhatchee drainage basin (which includes some smaller streams and rivers). There remains considerable uncertainty as to whether this will occur, but given high soil moisture levels it would not take much rainfall to create flooding problems in those areas. The most up-to-date river forecast information can always be found on our AHPS page (below). http:/water.weather.gov/ahps2/index.php?wfo=tae && .Prev Discussion [304 AM EDT]... .Short Term [Saturday Through Sunday]... The upper ridge will be temporarily shunted southeast of the area from tonight through Saturday with heights building once again on Sunday as another upstream trough amplifies across the Rockies. The surface high will remain in place across the region. The ridge will keep any synoptic scale systems from approaching the area. However, increasing moisture and instability will contribute to a gradual upward trend in PoPs into Saturday. After that, the deep layer ridging will re-assert itself with PoPs lowering, at least across our western zones. Rainfall totals are not expected to be high enough for any flooding concerns. Increased clouds and showers will keep daytime temps a bit lower than recent days with somewhat hotter temps returning for Sunday. Min temps will remain in the 60s. .Long Term [Sunday Night Through Friday]... While no systems of any real significance are expected to impact our CWA until perhaps the very end of the period as the next deepening upper level trough approaches from the west, there are still some discrepancies yet to be resolved in the Global models for the beginning of the period. If the GFS is correct, the next shortwave will swing rapidly through the region by this Saturday night with generally fair and warm weather for the bulk of the period as zonal flow gradually transitions into upper level ridging. The ECMWF, on the other hand, keeps conditions a bit more unsettled on Sunday and Monday, as it attempts to cutoff a weak upper level low over the northern Gulf coast. However, should this even occur, it will do so under rising heights, so while this may make for a somewhat unsettled end to the upcoming weekend, only sct showers and storms would likely be the end result, and certainly not significant enough to cancel outdoor plans. .Aviation... [Through 06Z Saturday] MVFR restrictions in a fog/ceiling mix may be possible briefly this morning at ECP, TLH, and VLD. Otherwise, VFR will prevail today under a scattered to broken mid and high level clouds deck. Southerly winds may be gusty at times to around 20 knots. .Marine... High pressure will continue to ridge from the Atlantic westward across the Gulf Coast states through the period. This will maintain onshore winds across the waters, primarily out of the southeast. Wind speeds are expected to remain below headline criteria. A front will approach from the northwest on Tuesday. .Fire Weather... Moisture and rain chances will be increasing over the next few days and hazardous fire weather conditions are not anticipated. Dispersions will likely be rather high this afternoon. && .Preliminary Point Temps/PoPs... Tallahassee 89 66 87 63 89 / 0 10 20 10 20 Panama City 84 70 81 69 84 / 10 50 30 20 20 Dothan 89 66 84 65 89 / 10 30 40 20 30 Albany 90 67 85 64 90 / 0 20 40 20 30 Valdosta 93 66 89 63 92 / 0 10 20 10 30 Cross City 90 66 87 64 88 / 0 10 10 10 30 Apalachicola 82 69 81 68 82 / 0 30 20 10 20 && .TAE Watches/Warnings/Advisories... FL...High Rip Current Risk through this evening for Coastal Bay- Coastal Franklin-South Walton. GA...None. AL...None. GM...None. && $$ NEAR TERM...LAMERS SHORT TERM...WOOL LONG TERM...GOULD AVIATION...HARRIGAN MARINE...WOOL FIRE WEATHER...HARRIGAN HYDROLOGY...LAMERS
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
910 AM EDT FRI MAY 9 2014 .UPDATE (REST OF TODAY AND TONIGHT)... 13Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUES TO SHOW AN AMPLIFIED UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. LONGWAVE TROUGHING SITS OVER THE CENTRAL PLAINS WITH A POTENT SHORTWAVE IMPULSE PIVOTING NORTHWARD OVER THE UPPER MS VALLEY/WESTERN GREAT LAKES. THE DOWNSTREAM FLOW THEN RIDGES UP OVER THE EASTERN SEABOARD EXTENDING FROM THE EASTERN GULF/FLORIDA PENINSULA TO QUEBEC. THIS RIDGE WILL REMAIN PARKED OVER OUR LOCAL AREA FOR ONE MORE DAY PROVIDING WARM AND MOSTLY DRY CONDITIONS. WV IMAGERY SHOWS A BIT MORE UPPER LEVEL MOISTURE HAS WORKED OVERHEAD COMPARED TO PREVIOUS DAYS...AND THIS WILL COME IN THE FORM OF PERIODIC CIRRUS. THIS HIGH LEVEL MOISTURE IS SHOWN ON THE 12Z KTBW SOUNDING ABOVE 400MB...HOWEVER BELOW THIS LEVEL...THE SUPPRESSION FROM THE UPPER RIDGE CONTINUES TO SUPPLY US WITH A DRY COLUMN THROUGH A MAJORITY OF THE TROP. A STRONG SUBSIDENCE INVERSION IS ALSO SEEN IN THE SOUNDING PROFILE AROUND 900MB. THERE ARE ACTUALLY SOME DECENT LAPSE RATES IN THE LOWER LEVELS ABOVE THIS INVERSION...HOWEVER THE DEPTH OF THE DRY AIR AND THE OVERALL SUPPRESSION SHOULD KEEP ANY SEA-BREEZE SHOWERS VERY LIMITED. AT THE SURFACE...RIDGE OF HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC CONTINUES TO RIDGE BACK TO THE WEST WITH AN AXIS NEAR THE I-10 CORRIDOR. OUR POSITION TO THE SOUTH OF THIS RIDGE AXIS IS PROVIDING A LIGHT SOUTHEAST FLOW TO THE REGION. REST OF TODAY... MOSTLY SUNNY SKIES TO START THE MORNING OFF AT MOST LOCATIONS. THE NEAR 100% INSOLATION WILL ALLOW TEMPERATURES TO WARM QUICKLY INTO THE 80S...ON THEIR WAY TO AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S ACROSS THE INTERIOR AND LOWER/MIDDLE 80S CLOSER TO THE COAST. WILL SEE ENOUGH TERRESTRIAL HEATING TO FORCE A SEA-BREEZE THIS AFTERNOON...HOWEVER THE SOUTHEAST FLOW JUST ABOVE THE SURFACE IS 15+ KNOTS PER MODEL AND CONFIRMED BY KTBW SOUNDING. THIS FLOW WOULD BE ENOUGH TO PIN ANY SEA-BREEZE TO THE COAST (OR EVEN KEEP IT JUST OFFSHORE). HOWEVER...NAM/LOCAL HIRES WRFARW GUIDANCE BOTH SHOWING THIS FLOW RELAXING SOMEWHAT FOR THE AFTERNOON...SO WILL SHOW THE SEA-BREEZE MAKING SOME INLAND PROGRESS...IT JUST MAY BE LATER ARRIVING THAN DURING PREVIOUS DAYS. THE OPPOSING FLOW WILL ADD SOME LOW LEVEL CONVERGENCE/FOCUS ALONG THIS SEA-BREEZE BOUNDARY. CAN NOT RULE OUT A FEW ISOLATED/BRIEF SHOWERS AFTER 3-4PM...HOWEVER...WITH THE RIDGE ALOFT...UPDRAFTS ARE GOING TO STRUGGLE ABOVE 10-12KT...AND ANY CUMULUS TOWERS WILL BE FIGHTING SIGNIFICANT DRY AIR INTRUSION. FOR NOW WILL LEAVE MENTION OF SHOWERS OUT OF THE FORECAST AS RAIN CHANCES ARE REALLY 10% OR LESS FOR ANY PARTICULAR SPOT. HOWEVER...WILL NOT BE SURPRISED TO SEE A SHOWER OR 2 POP UP ON RADAR LATER TODAY. LIKELY TO DISAPPEAR FROM RADAR AS QUICKLY AS THEY APPEAR THOUGH. TONIGHT... SHORTWAVE ENERGY RIDING NORTHWARD FROM THE WESTERN GULF OF MEXICO TO THE FLORIDA PANHANDLE/GEORGIA VICINITY WILL DE-AMPLIFY THE UPPER RIDGE AND BEGIN TO SHIFT ITS AXIS SOUTH AND SOUTHEAST. BY MORNING THE UPPER RIDGE AXIS WILL BE DOWN OVER SOUTH FLORIDA. THE SURFACE RIDGE WILL REMAIN IN PLACE WITH A LIGHT SOUTHEAST FLOW OVER THE AREA. THIS FLOW LOOKS TO REMAIN STRONG ENOUGH (ESPECIALLY JUST ABOVE THE SURFACE) TO SUPPRESS ANY SIGNIFICANT FOG DEVELOPMENT. THIS IS SHOWN IN THE SREF VISIBILITY PROBS OVERNIGHT WHICH ARE UNDER 10% FOR VIS < 3 MILES. A MILD NIGHT UPCOMING WITH LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S. SHOULD GET DOWN INTO THE MIDDLE 60S FOR INLAND LEVY COUNTY. NORMALLY WARMER SPOTS ALONG THE COAST SUCH AS ST PETE WILL HOLD IN THE MIDDLE 70S. HAVE A GREAT FRIDAY EVERYONE! && .MID TERM (SATURDAY-SUNDAY)... HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH THE PERIOD. THE EAST/WEST COAST SEA BREEZES SHOULD BE ENOUGH TO SPARK ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON...SO WILL INCLUDE SLIGHT CHANCE/LOW CHANCE POPS IN THE FORECAST IN MOST LOCATIONS. HIGH TEMPERATURES WILL GENERALLY TOP OUT IN THE UPPER 80S TO LOWER 90S BOTH DAYS...WITH LOWS SATURDAY NIGHT RANGING FROM THE MID TO UPPER 60S ACROSS THE INTERIOR COOL SPOTS TO THE LOWER 70S ALONG THE COAST. && .LONG TERM (SUNDAY NIGHT-FRIDAY)... MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH EARLY NEXT WEEK...WITH SOLUTIONS THEN DEVIATING WITH RESPECT TO THE HANDLING OF AN EASTERLY WAVE DURING THE MIDDLE TO LATTER PORTION OF NEXT WEEK. WILL FOLLOW A BLENDED APPROACH TO THE FORECAST GIVEN THE UNCERTAINTY...AND THIS WILL RESULT IN CHANCES FOR MAINLY AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE LONG TERM PERIOD. AT THIS POINT...IT APPEARS THAT THE HIGHEST PROBABILITIES FOR RAINFALL WILL FALL IN THE WEDNESDAY/THURSDAY TIME FRAME WHEN THE DEEPEST MOISTURE WILL BE IN PLACE. TEMPERATURES ARE EXPECTED TO RUN CLOSE TO NORMAL THROUGH THE LONG TERM PERIODS. && .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGH THE REST OF THE DAY AND EVENING. EXPECT A FEW-SCT CU FIELD TO DEVELOP DURING THE AFTERNOON WITH BASES BETWEEN 4-6KFT. SOUTHEAST FLOW OVERNIGHT LOOKS TO REMAIN ELEVATED ENOUGH TO PREVENT MUCH IN THE WAY OF FOG DEVELOPMENT. NOT OUT OF THE QUESTION TO SEE A BRIEF MVFR PERIOD AT KLAL OR KPGD TOWARD SUNRISE ON SATURDAY...HOWEVER AT THIS TIME CONFIDENCE OF REDUCED VISIBILITIES AT EITHER TERMINAL ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS. && .MARINE... BREEZY CONDITIONS OVER THE COASTAL WATERS WILL SETTLE DOWN LATER THIS MORNING WITH WINDS TURNING ONSHORE NEAR THE COAST DURING THE EARLY TO MID AFTERNOON. WINDS WILL SHIFT BACK TO THE SOUTHEAST OVERNIGHT AND BECOME BREEZY ONCE AGAIN...HOWEVER AT THIS TIME IT DOES NOT APPEAR AS THROUGH CAUTIONARY LEVEL WINDS OF 15-20 KNOTS WILL BE REACHED. THIS CONTINUED PATTERN OF ONSHORE AFTERNOON WINDS AND OFFSHORE SLIGHTLY STRONGER FLOW AT NIGHT AND DURING THE EARLY MORNING HOURS WILL CONTINUE THROUGH THE UPCOMING WEEKEND AS HIGH PRESSURE REMAINS PARKED TO THE NORTH OF THE FORECAST WATERS. && .FIRE WEATHER... RELATIVE HUMIDITY WILL BRIEFLY APPROACH CRITICAL LEVELS DURING THE MID/LATE AFTERNOON AWAY FROM THE COAST. IN ADDITION...EFFICIENT TRANSPORT WINDS AND GOOD DIURNAL MIXING WILL RESULT IN HIGH DISPERSION INDICES THIS AFTERNOON AWAY FROM THE COAST AS WELL. LOW LEVEL MOISTURE WILL INCREASE FURTHER INTO THE WEEKEND PREVENTING RELATIVE HUMIDITY FROM REACHING CRITICAL LEVELS EITHER SATURDAY OR SUNDAY. THERE WILL BE BETTER CHANCES FOR A FEW AFTERNOON STORMS ALONG THE SEA-BREEZE THIS WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... TPA 90 72 88 73 / 0 0 10 0 FMY 92 70 91 71 / 0 0 20 10 GIF 90 70 90 71 / 0 0 20 20 SRQ 87 70 87 71 / 0 0 10 10 BKV 91 65 89 66 / 10 10 10 10 SPG 89 74 88 74 / 0 0 10 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/AVIATION/MARINE/FIRE WEATHER...MROCZKA MID TERM/LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1012 AM EDT FRI MAY 9 2014 .SYNOPSIS... HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC WILL WEAKEN SATURDAY AS A DISSIPATING FRONTAL SYSTEM MOVES INTO THE AREA. HIGH PRESSURE REGAINS CONTROL FOR THE BEGINNING OF NEXT WEEK. ANOTHER FRONT IS EXPECTED TO AFFECT THE REGION LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...THE SURFACE RIDGE WILL CONTINUE TO EXTEND INTO THE FORECAST AREA FROM THE ATLANTIC. THE LOWER LEVELS SHOULD REMAIN RELATIVELY DRY. SATELLITE TRENDS SHOW CONSIDERABLE MID AND UPPER CLOUDINESS MOVING INTO THE AREA IN THE SOUTHWEST FLOW AHEAD OF THE TROUGH. A WEAK MID-LEVEL SHORTWAVE TROUGH...A LITTLE LOW- LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS HEATING COULD POSSIBLY SUPPORT THUNDERSTORMS LATE...BUT THE CHANCE IS VERY LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE LATEST HRRR INDICATES JUST ISOLATED SHOWERS LATE IN THE DAY. THE FORECAST APPEARS ON TRACK WITH POPS LESS THAN 20 PERCENT. IT SHOULD BE A LITTLE COOLER THAN PREVIOUS DAYS BECAUSE OF CLOUDINESS. HOWEVER...IT WILL LIKELY NOT BE NOTICEABLE BECAUSE OF A SLIGHT INCREASE IN HUMIDITY. TONIGHT...THE MODELS INDICATE AN INCREASE IN MOISTURE...BUT THE DEEPER MOISTURE REMAINS WEST OF THE AREA. THERE MAY BE AN INCREASE IN INSTABILITY ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH. HOWEVER...MOISTURE SHOULD REMAIN LIMITED AND ANY CONVERGENCE ASSOCIATED WITH A LEE-SIDE TROUGH SHOULD BE WEAK. THE SHOWER OR THUNDERSTORM CHANCE IS LOW. THE NAM AND GFS MOS HAVE POPS LESS THAN 20 PERCENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... THE MODELS INDICATE AN INCREASE IN MOISTURE SATURDAY ASSOCIATED WITH THE REMNANTS OF A COLD FRONT. PRECIPITABLE WATER IS FORECAST TO INCREASE TO AROUND 1.5 INCHES WITH WEAK LIFT AHEAD OF THE BROAD UPPER-LEVEL TROUGH. THERE SHOULD ALSO BE LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH. KEPT CHANCE POPS SATURDAY. THE GUIDANCE CONSENSUS SUPPORTS POPS AROUND 30 PERCENT. THUNDERSTORMS MAY LINGER SATURDAY EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT PLUS HEATING. THE MODELS ARE CONSISTENT SHIFTING DIMINISHING MOISTURE EAST SATURDAY NIGHT WITH H5 HEIGHTS BUILDING. THE MODELS SHOW THE RIDGE REMAINING DOMINATE THROUGH SUNDAY NIGHT WITH LITTLE MOISTURE. THE NAM AND GFS MOS SUPPORT POPS LESS THAN 20 PERCENT LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT. USED THE WARMER TEMPERATURE GUIDANCE BECAUSE OF RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. THE LOW TEMPERATURE GUIDANCE WAS CLOSE. && .LONG TERM /MONDAY THROUGH THURSDAY/... THE GFS AND ECMWF DISPLAY A MAINLY DRY PATTERN MONDAY AND TUESDAY. THE UPPER LEVEL RIDGE CONTINUES ACROSS THE REGION THROUGH TUESDAY WHILE SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC RIDGES INTO THE SOUTHEASTERN STATES. THE GFS...ECMWF...AND EKD MOS INDICATE POPS OF 20 PERCENT OR LESS. A COLD FRONT THURSDAY MAY BRING AN INCREASED CHANCE OF THUNDERSTORMS. BOTH THE GFS AND ECMWF DISPLAY AN OFFSHORE LOW OR TROUGH WHICH WOULD LIMIT CONVERGENCE IN THE FORECAST AREA. THE GFS...ECMWF AND EKD MOS HAVE POPS OF 20 TO 40 PERCENT WEDNESDAY AND THURSDAY. TEMPERATURES SHOULD BE ABOVE NORMAL IN THE UPPER 80S AND LOWER 90S SUNDAY THROUGH WEDNESDAY...THEN NEAR NORMAL THURSDAY. SHOULD SEE OVERNIGHT LOWS IN THE LOW TO MID 60S. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... HIGH-LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS THE TAF SITES THROUGH THE PERIOD IN THE SOUTHWEST FLOW ALOFT. CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS MID-LEVEL SHORTWAVE TROUGH COULD HELP SUPPORT THUNDERSTORMS BUT THE CHANCE IS VERY LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE HRRR INDICATES JUST ISOLATED COVERAGE LATE THIS AFTERNOON AND THE CHANCE IS MUCH TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. THE NAM BUFKIT MOMENTUM TRANSFER TOOL...GFS LAMP...AND KCAE 88D VAD WIND PROFILE INDICATE WIND GUSTS 20 TO 25 KNOTS THIS AFTERNOON. THE HIGH CLOUDINESS SHOULD LIMIT MIXING SOMEWHAT SO FORECASTED GUSTS NEAR THE LOWER END OF THE RANGE. CLOUDINESS AND MIXING SHOULD LIMIT FOG DURING THE EARLY MORNING HOURS SATURDAY. THE GFS AND NAM MOS INDICATE VFR OR MVFR CONDITIONS WITH MVFR FOG CONFINED TO THE RIVER-VALLEY TERMINALS OF AGS AND OGB. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH TUESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ Area Forecast Discussion National Weather Service Lincoln IL 926 AM CDT Fri May 9 2014 .DISCUSSION... ISSUED 926 AM CDT Fri May 9 2014 Overnight convection has lifted northeastward out of the area, leaving behind only a few scattered showers along/east of the I-57 corridor this morning. Cold front is currently approaching the Illinois River. Ahead of the boundary, southwesterly winds continue with 14z/9am temps in the upper 60s/lower 70s. Meanwhile behind the front, W/NW winds have dropped the temp into the upper 50s around Galesburg. Front will only make slow progress eastward today, with additional convection likely developing ahead of it during the afternoon hours. NAM and HRRR both suggest scattered thunderstorms will develop in the instability axis along/south of I-70 by mid to late afternoon. In the meantime, relatively stable airmass in the wake of the earlier convection should keep things quiet through early afternoon. Have updated the forecast to significantly reduce POPs this morning. Will only mention isolated to scattered showers east of the Illinois River through midday, then will increase POPs to likely for showers/thunder across the SE KILX CWA this afternoon. Barnes && .AVIATION... ISSUED 656 AM CDT Fri May 9 2014 The slow moving cold front will finally push across the terminal sites today. MVFR clouds between 1500-2500 FT will become more widespread during the first 3 to 5 hours of the TAFs, as low clouds develop near the front. A break in the rain should eventually work its way from west to east behind the front. The front should pass PIA to SPI by 16z, then reach CMI to DEC by 21z. The MVFR cigs should gradually give way to VFR cigs behind the front this afternoon. Storm redevelopment is expected later this afternoon ahead of the front, but the majority of those storms should be southeast of the TAF sites. DEC and CMI could get clipped as the line of storms develops after 20z, so a VCTS was left in the TAFS from 20z to 01z. Surface winds will remain out of a southerly direction at 12 to 17 kts early this morning with gusts to 25kt or higher at times in and near any thunderstorms. Winds will veer more into the southwest and then west this afternoon with speeds in the 15 to 20 kt range with gusts up to 30 kts possible, especially if we can get some sunshine to break through. VFR conditions are expected across the entire forecast area this evening thru 12z. Shimon && .PREV DISCUSSION... ISSUED 312 AM CDT Fri May 9 2014 SHORT TERM...Today through Sunday Surface map at 06z indicated 999 mb low pressure near KMSP with a cold front trailing south through central IA and MO then down into central OK where a weaker 1007 mb low resided. South flow off the Gulf continued to pump in low to mid 60s dewpoints to central/SE IL. Aloft, W/V imagery showed a strong warm conveyor belt overhead which has produced rounds of thunderstorms mainly over eastern IL for the past few hours. Another shortwave just entering SW MO was sparking new thunderstorm development and this is expected to shift northeast across the area through mid-morning as the cold front moves into the western CWA. Short range models including HRRR and SPC 4km WRF suggest this activity will push east of the area by 18z while the cold front gradually tracks ESE across the CWA. It appears convective debris will clear out by early afternoon allowing upper 70s temps and mid 60s dewpoints to set up across the eastern CWA ahead of the front. This would suggest CAPE values around 2k J/kg with 40 kts 0-6km bulk shear overhead. Questions remain if new convection will fire along the front as low level convergence becomes less favorable. Any storms that develop could become severe with damaging wind gusts and hail given low wet-bulb zero heights near 9k ft. Radar simulations show most favored areas would be near or south of I-70 in a 21z-02z window. Any lingering activity will shift east of the region overnight as brief surface ridging moves overhead. This to provide dry and seasonably warm weather Saturday with highs in the upper 70s/lower 80s. The pattern turns active again Saturday night as warm advection precip ahead of the next Plains low develops in MO then lifts northeast across the CWA. Rising heights and another round of southerly flow ahead of this low should send another strong warm front north of the area Saturday night or Sunday with more associated precip chances. With the front now expected north by Sunday afternoon and with 850 mb temps rising into the mid teens have boosted highs to the low/mid 80s. Mixed signals if the warm sector will be dry/capped and as a result chance pops continue through Sunday night. LONG TERM...Monday through Thursday 00z model suite still has some major timing differences with a strong cold frontal passage Monday evening/night. EC continues to be most consistent and slowest solution. Depending on timing, severe weather will be a threat given dynamics with this system. Trends continue to show a major pattern change behind this cold front, as a deep upper level trough sets up over the central U.S. This will bring well below normal temps to the region as 850 mb readings are shown in the low single digits Tue-Thu, suggesting highs mainly in the 60s as lows in the 40s. With cold air and deep cyclonic flow overhead, diurnal heating may lead to scattered instability showers Tue-Thu. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1020 AM EDT FRI MAY 9 2014 .SYNOPSIS... ISSUED AT 358 AM EDT FRI MAY 9 2014 A LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS THE UPPER GREAT LAKES TODAY AND ACROSS ONTARIO TONIGHT. A COLD FRONT TRAILING SOUTH FROM THE LOW WILL MOVE ACROSS OUR AREA THIS AFTERNOON AND TONIGHT. OCCASIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED AHEAD OF THE COLD FRONT TODAY WITH SCATTERED STORMS POSSIBLY LINGERING INTO THIS EVENING. HIGHS TODAY WILL BE IN THE MID 70S WITH LOWS TONIGHT RANGING FROM THE UPPER 40S OVER SOUTHWEST MICHIGAN AND NORTHWEST INDIANA... TO THE UPPER 50S OVER NORTHWEST OHIO. && .UPDATE... ISSUED AT 1020 AM EDT FRI MAY 9 2014 LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS CURRENTLY APPROACHING THE AREA...ASSOCIATED WITH A WEAK VORT MAX JUST AHEAD OF THE MAIN SURFACE COLD FRONT. SPC/RAP MESOANALYSIS SHOWS ALMOST NO INSTABILITY ACROSS NORTHERN INDIANA...EXPLAINING THE LACK OF RECENT LIGHTNING. EXPECT THIS WILL CONTINUE TO BE THE CASE THROUGH THE MORNING WITH OVERCAST SKIES AND SOME LIGHT SHOWERS CONTINUING AHEAD OF THE MAIN LINE. LATEST RAP13 AND HRRR SHOW ONLY A FEW HUNDRED J/KG OF SBCAPE THROUGH THE EARLY AFTERNOON. SEVERE WEATHER POTENTIAL WITH THIS ACTIVITY IS VERY LOW BUT A FEW WIND GUSTS AROUND 40MPH AND SOME SMALL HAIL WILL BE POSSIBLE GIVEN 850MB WINDS OF 40-50 KNOTS AND RELATIVELY COLD TEMPS ALOFT/LOW FREEZING LEVELS. HI-RES GUIDANCE INDICATES THE POTENTIAL FOR A SLIGHT RECOVERY IN OUR WEST AND SOUTHWEST COUNTIES LATER THIS AFTERNOON WITH MIDLEVEL DRY AIR BEHIND THE INITIAL SHORTWAVE POSSIBLY ALLOWING FOR A FEW PEAKS OF SUN...SIMILAR TO CURRENT VIS IMAGERY OVER ILLINOIS. WINDOW OF OPPORTUNITY FOR SEVERE WEATHER WILL BE SMALL THOUGH AND FORECAST SBCAPES ARE STILL ONLY AROUND 1000 J/KG...LIMITING UPDRAFT STRENGTH. WILL BE DIFFICULT TO ADEQUATELY DESTABILIZE AFTER THIS MORNING RAIN. ONCE AGAIN...STRAIGHT LINE WINDS AND SMALL HAIL WOULD BE THE MAIN THREATS WITH THE BEST CHANCES PROBABLY IN THE 4-8PM TIMEFRAME BUT THE SEVERE WEATHER THREAT REMAINS HIGHLY CONDITIONAL AT THIS POINT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 348 AM EDT FRI MAY 9 2014 UPR TROF OVER THE PLAINS WILL LIFT NE ACROSS THE GRTLKS AND DEAMPLIFY TODAY-TNGT. LEAD SHRTWV WILL MOVE ACROSS OUR AREA THIS MORNING ACCOMPANIED BY A LOW LEVEL THETA-E PLUME/WK INSTABILITY RESULTING IN WIDESPREAD SHOWERS/TSTMS. MID LEVELS SHOULD DRY OUT IN WAKE OF THIS LEAD WAVE THIS AFTN... ALLOWING FOR DECREASING CLOUDINESS AND DESTABILIZATION AS LOW LEVELS REMAIN MOIST AHEAD OF SFC CDFNT AND APCHG MAIN TROF. NAM SUGGESTS INSTABILITY WILL REACH AROUND 1500J/KG OVER NRN INDIANA AND SRN MI THIS AFTN WITH 0-6KM MAINLY UNIDIRECTIONAL SHEAR INCREASING TO AROUND 50KT. THOUGH FORCING APPEARS FAIRLY WK THIS AFTN AS MOISTURE CONVERGENCE ALONG CDFNT MINIMAL AND UPR TROF DEAMPLIFING... MODERATE INSTABILITY... STRONG SHEAR... AND DRY MID LEVELS SUGGEST A POTENTIAL FOR SVR TSTMS WITH DAMAGING WINDS AND LARGE HAIL... MAINLY ACROSS NRN INDIANA IF DESTABILIZATION OCCURS AS FCST AND FORCING IS SUFFICIENT FOR CONVECTION TO DEVELOP DURING PEAK HEATING. CURRENT TEMPS NEAR PREVIOUS FCST HIGHS FOR TODAY... BUT TEMPS SHOULD RISE LITTLE THIS MORNING WITH WIDESPREAD SHOWERS MOVG THROUGH AND CONSIDERABLY COOLER ALOFT THAN YDAY... SO EXPECT HIGHS TODAY GENERALLY IN THE M70S. WKNG CDFNT WILL MOVE ACROSS THE AREA TONIGHT PRBLY ACCOMPANIED BY SCT SHOWERS/TSTMS THIS EVE... WITH CONVECTION DIMINISHING AND MOVG EAST OVERNIGHT. WK HIGH PRESSURE WILL BUILD INTO THE AREA OVERNIGHT ALLOWING FOR CLEARING SKIES. SOME PATCHY FOG PSBL ACROSS WRN PORTIONS OF THE AREA BUT HELD OFF ADDING AT THIS JUNCTURE. TEMPS WILL BE CONSIDERABLY COOLER WITH LOWS RANGING FROM THE U40S NW TO THE U50S SE. && .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 348 AM EDT FRI MAY 9 2014 LARGE SCALE SUBSIDENCE/DRYING WILL SUPPORT A DRY/COOLER SATURDAY AS A WEAK AREA OF HIGH PRESSURE BUILDS IN BEHIND FRIDAY NIGHT`S FRONTAL BOUNDARY. STRENGTHENING SOUTHWEST FLOW IN ADVANCE OF LONGWAVE TROUGH AMPLIFICATION INTO THE WESTERN US SUNDAY AND HIGH PLAINS EARLY NEXT WEEK WILL ALLOW GULF MOISTURE TO ADVECT WELL NORTH INTO THE GREAT LAKES REGION DURING THIS TIME. LOW LEVEL THETA-E GRADIENT/WARM FRONT IN ADVANCE OF THIS SYSTEM ON LLJ NOSE MAY BRING SOME MAINLY ELEVATED CONVECTION TO THE AREA (FROM SW TO NE) LATER SATURDAY NIGHT THROUGH SUNDAY NIGHT...WITH POPS KEPT IN THE LOW/MID CHC RANGE GIVEN THE ABSENCE OF ANY WELL-DEFINED MID/UPPER LEVEL FORCING. 00Z GUIDANCE CONTINUED THE TREND TOWARD THE SLOWER ECMWF SOLUTION REGARDING EASTWARD PROGRESSION OF THE UPPER TROUGH NEXT WEEK AS SYSTEM EVENTUALLY PHASES WITH A CANADIAN PRAIRIES UPPER LOW. THIS MAY LEAVE THE IWX CWA COMPLETELY IN THE WARM SECTOR BY MONDAY-MONDAY NIGHT...ALTHOUGH CANNOT RULE OUT PCPN GIVEN MOIST AIRMASS/WEAK CAPPING AND POTENTIAL FOR WEAK CONVECTIVELY ENHANCED/INDUCED SHORTWAVES TO LIFT NORTHEAST INTO THE AREA WITHIN SOUTHWEST FLOW. SHOWER/STORM CHANCES INCREASE AGAIN BY TUESDAY-TUESDAY NIGHT AS HEIGHT FALLS OVERSPREAD PRE-FRONTAL TROUGH OR COLD FRONT. HELD CLOSE TO PREV FCST (MID CHC POPS) BUT DID TREND TEMPS UP CLOSER TO WARMER ECM/MEX MOS AND HPC GUIDANCE MONDAY-TUESDAY. COOLER WX RETURNS WEDNESDAY INTO THURSDAY IN WAKE OF FRONT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 616 AM EDT FRI MAY 9 2014 SHOWERS WITH SOME EMBEDDED TSTMS EXPECTED TO MOVE ACROSS NRN INDIANA TODAY. CONDITIONS SHOULD MAINLY BE VFR BUT OCNL MVFR LIKELY DURING HEAVIER CONVECTION. DRIER AIR IN MID LEVELS WILL SPREAD INTO THE AREA THIS AFTN RESULTING IN DECREASING CLOUDINESS. TSTMS STILL PSBL UNTIL WKNG CDFNT MOVES THROUGH THE AREA THIS EVE BUT WITH MAGNITUDE OF DESTABILIZATION THIS AFTN QUESTIONABLE AND RATHER WK FORCING... CONTD TO LEAVE TAFS DRY FOR LATE AFTN/EVE. ALTHOUGH LLJ WILL LIFT NORTH OF THE AREA THIS MORNING... SW WINDS WILL CONT GUSTY AT TIMES THROUGH THE DAY AS DIURNAL MIXING INCREASES. SOME POTENTIAL FOR BR DEVELOPMENT OVERNIGHT AS WINDS DIMINISH... ESPECIALLY AT SBN WHERE POST FRONTAL STRATO CU SHOULD CLEAR OUT LATE... BUT MOISTURE VERY SHALLOW ON FCST SOUNDINGS SO LEFT MENTION OUT OF TAFS ATTM. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LMZ043- 046. && $$ UPDATE...AGD SYNOPSIS...JT SHORT TERM...JT LONG TERM...STEINWEDEL AVIATION...JT VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
513 AM MDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 258 AM MDT FRI MAY 9 2014 EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS CONFLUENT FLOW ENTERING ROCKIES OVER PLAINS ON BACK SIDE OF DEPARTING TROUGH...WITH WEAK SHORTWAVE ENERGY UPSTREAM NEAR DIFLUENT FLOW OVER GREAT BASIN. AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER OUR CWA WITH STATIONARY FRONT ALONG FRONT RANGING AND COLD FRONT OVER OK/TX PANHANDLES. RADAR SHOWS SOME VIRGA AND VERY LIGHT SPRINKLES LINGERING AS A SHORTWAVE IS EJECTING ACROSS THE SOUTHERLY PLAINS. WITH SUBSIDENCE BUILDING IN FROM THE NORTH THIS ACTIVITY LIKELY WONT LAST LONG. TEMPS HAVE DROPPED INTO THE MID 30S ACROSS THE WEST...AND WE COULD SEE A FEW LOW TEMPS AROUND FREEZING BY SUNRISE. A WEAK SHORTWAVE TROUGH WILL PASS NORTH OF THE CWA THIS AFTERNOON AND EVENING AND MAY COMBINE WITH AFTERNOON/EVENING INSTABILITY TO PRODUCE A FEW THUNDERSTORMS OVER NE COLORADO. VERY DRY LOW LEVELS WOULD LIMIT PRECIP REACHING THE SURFACE. DECIDED TO KEEP SMALL AREA OF OUR NW CWA WITH ISO THUNDER AROUND 00Z AND OTHERWISE LIMITED PRECIP MENTION TO SPRINKLES. SEASONAL TEMPS SHOULD RETURN AS SOUTHERLY FLOW REDEVELOPS TODAY...WITH HIGHS IN THE 70S AND OVERNIGHT LOWS TONIGHT IN THE LOW-MID 40S (MAYBE A FEW SPOTS A LITTLE COLDER WEST). SATURDAY-SUNDAY NIGHT...COMPLICATED FORECAST AS THE NEXT STRONG UPPER TROUGH IS EXPECTED TO IMPACT THE CENTRAL ROCKIES AND PLAINS. SOUTHWESTERLY FLOW DEVELOPS ACROSS THE ROCKIES WHICH WOULD INITIALLY LIMIT ANY SHOWER/THUNDERSTORM CHANCES TO THE NW SATURDAY. HOWEVER BY SATURDAY NIGHT THE MAIN TROUGH BEGINS TO SLIDE EAST ALLOWING GOOD MOISTURE AND LIFT OT BUILD OVER THE CWA. BEST PRECIP CHANCES ACROSS THE CWA STILL LOOKS TO BE ON SUN/SUN NIGHT AND MODELS SHOW REASONABLE AGREEMENT ON MEASURABLE PRECIP SO I BUMP POPS INTO 60-70 RANGE FOR THOSE PERIODS. A LITTLE LESS CONFIDENT ON AREA OF BEST PRECIP...THOUGH PARTS OF THE REGION (ESPECIALLY WEST) COULD SEE DECENT LIQUID ACCUMULATION WITH THIS EVENT (0.15-0.75"). REGARDING WEATHER TYPE...VERY LIMITED INSTABILITY THROUGH MOST OF THE EVENT...SO ONLY KEPT THUNDER MENTION SATURDAY AFTERNOON/EVENING. TEMP PROFILES AND WBZ HEIGHTS WOULD INDICATE A RAIN/SNOW MIX OR A COMPLETE CHANGEOVER ACROSS THE WESTERN HALF OF THE CWA SUNDAY NIGHT. WARM GROUND TEMPS MAY LIMIT ANY SNOW ACCUMULATION (ASSUMING LIGHTER RATES). IN ADDITION TO WARM GROUND TEMPS...CONFIDENCE OF CHANGEOVER TIMING IS LOW SO I LEFT ACCUMULATION MENTION OUT OF FORECAST. I DID INCLUDE RAIN/SNOW MENTION AND A BRIEF PERIOD OF ALL SNOW AROUND SUNRISE EARLY MONDAY MORNING. WILL NEED TO WATCH HOW THIS SYSTEM EVOLVES TO ZERO IN ON THESE DETAILS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 258 AM MDT FRI MAY 9 2014 MODELS ARE STILL IN DISAGREEMENT WITH THE POSITION AND PROGRESSION OF THE UPPER LEVEL TROUGH IN THE EXTENDED. GFS STILL MOVES IT FURTHER EAST MORE QUICKLY THAN THE ECMWF. HOWEVER...THE TROUGH WILL CONTINUE TO INFLUENCE THE CWA ON MONDAY. TEMPERATURES MONDAY MORNING APPEAR COLD ENOUGH FOR LIGHT SNOW TO CONTINUE OVER EASTERN COLORADO WITH A RAIN SNOW MIX IN NORTHWEST KANSAS IN COUNTIES BORDERING EASTERN COLORADO. TEMPERATURES SHOULD WARM ENOUGH BY 15Z FOR ALL PRECIPITATION TO BE RAIN...WITH THE CHANCE FOR RAIN CONTINUING MONDAY AFTERNOON. MONDAY WILL REMAIN BREEZY AS THE TIGHT PRESSURE GRADIENT STAYS OVER THE CWA UNTIL MONDAY NIGHT WHEN IT RELAXES AND SURFACE HIGH PRESSURE SETTLES IN OVER COLORADO. TUESDAY THROUGH WEDNESDAY SHOULD REMAIN DRY AS THE UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES BECOMES MORE INFLUENTIAL IN THE HIGH PLAINS. BY THURSDAY...A SHORTWAVE TROUGH WILL ROTATE AROUND THE UPPER TROUGH OVER THE GREAT LAKES REGION SENDING A WEAK COLD FRONT THROUGH THE CWA. SHOWERS AND THUNDERSTORMS COULD DEVELOP AHEAD OF THE FRONT...SINCE THE GFS DOES HAVE A FEW HUNDRED J/KG OF CAPE OVER EASTERN COLORADO. AS PREVIOUSLY MENTIONED...THE MODELS ARE HAVING A HARD TIME COMING TO A CONSENSUS FOR ANY DAY IN THE EXTENDED...SO AM TRYING TO GET AWAY FROM GETTING TOO DETAILED FOR THUNDERSTORM POTENTIAL IN DAY 7. WELL BELOW AVERAGE TEMPERATURES CAN BE EXPECTED TO START OFF THE EXTENDED PERIOD WITH HIGHS ON MONDAY IN THE LOW TO UPPER 50S. LOWS MONDAY NIGHT WILL BE IN THE LOW 30S TO LOW 40S WITH HIGHS ON TUESDAY IN THE LOW TO MID 60S. SLIGHTLY BELOW TO NEAR NORMAL TEMPERATURES WILL TAKE OVER THROUGH THE REST OF THE EXTENDED WITH HIGHS IN THE MID 60S TO LOW 70S ON WEDNESDAY AND THURSDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 512 AM MDT FRI MAY 9 2014 VFR CONDITIONS WILL PREVAIL AT BOTH KGLD AND KMCK TERMINALS THROUGH THE TAF PERIOD. SW WINDS WILL INCREASE SLIGHTLY TO BE AROUND 12-15KT DURING THE DAYTIME PERIOD. AFTER SUNSET LIGHT AND VARIABLE WINDS ARE THEN EXPECTED UNTIL WINDS SHIFT TO THE WEST AND INCREASE BACK TO THE 10-15KT RANGE BEHIND A QUICK MOVING FRONT. A FEW THUNDERSTORMS MAY DEVELOP THIS AFTERNOON AND EVENING AS A WEAK DISTURBANCE MOVES THROUGH THE REGION...HOWEVER ANY THUNDERSTORM ACTIVITY SHOULD REMAIN WELL NORTHWEST OF BOTH TERMINALS. THERE COULD STILL BE VIRGA OR EVEN A FEW LIGHT SHOWERS AT BOTH TERMINALS...HOWEVER CONFIDENCE IS TOO LOW TO INCLUDE VCSH DURING THIS TAF UPDATE. && .FIRE WEATHER... ISSUED AT 243 AM MDT FRI MAY 9 2014 WITH WARMER TEMPS AND LOWER TD MIXING TO THE SURFACE WE COULD SEE RH VALUES WITHIN RFW CRITERIA ACROSS THE SOUTHERN PART OF OUR FORECAST AREA BOTH TODAY AND SATURDAY AFTERNOON/EARLY EVENING PERIODS. TODAY WINDS WILL BE WELL BELOW CRITERIA WITH WEAK GRADIENT IN PLACE...SO NO RFW PRODUCT ANTICIPATED. SW PRESSURE GRADIENT BEGINS TO INCREASE SATURDAY AHEAD OF DEEPENING UPPER LOW...THOUGH EVOLUTION OF SURFACE LOW AND FRONT POSITION WILL BE CRITICAL FOR WHERE WINDS WITHIN RFW CRITERIA WILL CROSS WITH LOW RH. NOT ENOUGH CONFIDENCE AT THIS POINT TO ISSUE A FIRE WEATHER WATCH FOR SATURDAY...BUT WE WILL PROBABLY NEED TO MONITOR. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...ALW AVIATION...DR FIRE WEATHER...DR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1153 AM EDT Fri May 9 2014 ...Forecast Update... Issued at 1145 AM EDT Fri May 9 2014 Band of showers continues to progress northeast over central KY at this time. There has not been any thunderstorms in this area so far, although latest Doppler radar is now showing increasing reflectivity values over parts of central KY, some expect isolated/scattered embedded cells early this afternoon as the rain continues pushing east. The rain will exit our eastern forecast area by 19z or so. After the rain ends, dry weather should prevail for a few hours this afternoon over central KY and south-central IN given the absence of enough forcing and initial instability. In the wake of this rain, clouds should thin with some breaks of sun, which should allow temperatures to reach near/around 80 in our western forecast area. Low-level warming combined with increasing mid-level lapse rates will increase instability over the lower OH Valley this afternoon as shown nicely by latest model soundings. Already, scattered cells are developing in central MO near frontal zone, although these should move northeast later today and initially not affect our area. Nevertheless, with increasing instability and potential diurnal heating boundaries, at least scattered convection should also develop later this afternoon just to out west and move into central KY and southern IN late this afternoon/evening. No major changes to tonight`s forecast at this time. Issued at 915 AM EDT Fri May 9 2014 An elongated axis of showers with a couple embedded bands of moderate to heavy rain and possibly an embedded elevated thunder- storm is moving northeast quickly this morning over west-central KY, now moving through our western forecast area. 06z model runs along with latest high-resolution HRRR model show that this axis should move steadily but coherently through our forecast area for the rest of this morning into early afternoon, before exiting to our east. Thus, have raised rainfall probabilities across our entire area. After this rain passes by, precip will end and then the question arises about what will happen later this afternoon. Still looks like some diurnal heating will commence with the atmosphere becoming more unstable. Models show that scattered convection could develop to our west this afternoon and then move east into our area later this afternoon and tonight. This scenario still seems reasonable, although am not able to pin things down more specifically at this time yet. Will continue to monitor trends through the day. No change to temperatures for today at this time. Will evaluate this later this morning into early afternoon. Issued at 640 AM EDT Fri May 9 2014 Did a quick update to back off PoPs a bit in the east this morning, but also increase PoPs slightly across our west and northwestern areas. Based on latest radar trends, expect a band of showers to affect portions of southern Indiana and Kentucky west of I-65 this morning. Expect this activity to diminish in intensity and coverage as it heads into a slightly drier and more stable airmass. Also backed off coverage this afternoon a bit given that overall model solutions are trending a bit drier. Likely PoPs appear to be too aggressive at this time and have backed them off into the scattered category. Also bumped temperatures in the west up slightly based on the assumption of lesser precipitation. .SHORT TERM (Now through Saturday)... Issued at 315 AM EDT Fri May 9 2014 In the near term, partly to mostly cloudy skies will be the rule across southern Indiana and central Kentucky this morning. Early morning IR imagery shows plenty of high level cloudiness streaming in from the west. Area radars are rather quiet across central KY but there are some returns back over southeastern Missouri that are heading eastward. We expect dry conditions for the remainder of the early morning hours. Temperatures remain quite mild with readings generally in the upper 60s to the lower 70s. Some of our cooler spots appear to have decoupled a bit and are seeing temperatures down into the upper 50s to around 60. We expect temperatures to slowly drop a few more degrees before rebounding towards sunrise. For Today, local and national high resolution modeling suggest area of convection across southeastern Missouri and northeastern Arkansas will grow upscale early this morning in response to a moderate low-level jet axis impinging northeastward into lower Mississippi Valley. This convection will work eastward during the morning hours and weaken a bit as it heads into central Kentucky. Persistent cloud cover and the remnants of this convective activity will likely keep instability down to marginal levels across the region. That is not to say that some areas may see stronger convection develop this afternoon. As the morning convection heads off to the east, we may see a few breaks develop which could lead to the development of pockets of higher instability during the afternoon. The best chances of this occurring would be out across the western areas. Overall, we still do not believe today will be a total washout. Though areas that do receive rain could get a nice soaking as the showers and storms move through the region. Highs today look to range from the middle to upper 70s in the west with upper 70s to lower 80s in the east. As we move into the evening hours, the higher resolution models do show a secondary line of storms forming along the frontal boundary approaching from the northwest. These storms probably will fire along a line from Indianapolis to St. Louis early this evening and then spread eastward into our region during the overnight period. Depending on how fast the early morning activity clears the region will be a determining factor in how strong the evening/overnight convection will be. With the line expected to come through at the time of minimum heating, we are not overly impressed with severe potential. Strong storms are certainly possible with damaging winds and hail being the primary threats. The activity should clear our region by early Saturday morning with temperatures only cooling into the mid-upper 60s. For Saturday, skies will likely start off mostly cloudy and then begin to clear from the west towards the east. While the upper flow takes on more of zonal pattern, there is difficulty in determining any real triggers for convection. Isolated-scattered convection will be possible with the highest concentration out toward the eastern portions of the forecast area. Though, by and large most areas will probably see mainly dry conditions. Highs for Saturday will be largely dependent on cloud cover during the afternoon. The multi-model consensus suggests highs in the upper 70s to near 80 in the west with mainly mid-upper 70s in the east. .LONG TERM (Saturday Night through Thursday)... Issued at 319 PM EDT Thu May 8 2014 As previously advertised, the Ohio Valley will be entering into an active pattern with showers and thunderstorms in the forecast for nearly every day in this period. Synoptically, Saturday will undergo a transition to more zonal at the 500mb level as the disturbance that brings rain to the region Friday night moves off toward the east. The forecast challenge for Saturday is how quickly the storms exit the forecast area as the deterministic models are struggling to come into better agreement. The trend has been just a bit slower, as evident from comparing previous runs with the 12Z runs. The NAM has been the quickest and conversely, the GFS messy and the slowest. The 09Z SREF seems to be the better compromise and have leaned toward it to show a general partial clearing from west to east throughout the day. Through the remainder of the weekend, much of Saturday night should be dry before the atmosphere recharges ahead of the next system. We`ll remain under southerly flow with high pressure centered over the Atlantic, allowing for GoMex moisture to pool into the region. Under this warm , moist air advection regime, Sunday`s forecast is also a bit tricky as we could see some sporadic storms firing up, especially with diurnal heating throughout the day. There is no obvious signal for which portions of the forecast area will see better rain chances than others given this type of setup so have broad brushed low-end chance PoPs throughout. After the sun sets on Sunday, should see a wane in storm coverage with the loss of the aforementioned heating. Something to watch for, however, is that the 12Z NAM is hinting at a mesoscale convective system to build across eastern KS/central MO and race off into the Great Lakes region late Saturday night through Sunday. This is in response to a surface low that develops just behind it. The NAM is depicting the eastern portion of this system to break off and jet across central KY before dying out as it loses its forcing mechanism. We`ll have to see how this evolves as we approach that time frame. As if the models haven`t been struggling enough, true temporal divergence becomes evident early next week as an amplified pattern sets up: troughing across the Plains and ridging over the East Coast. The GFS has been consistently fast with the ECMWF much slower. Have attempted to blend and compromise between the two, coming to the uncertain conclusion that Tuesday looks to be the best chance for active weather across the area. One thing the models do agree on is the pattern change coming by the middle to end of next week. Given the unsettled nature of the upcoming pattern, temperature forecasts will be difficult to nail down with certainty, with clouds potentially wrecking havoc on the highs/lows. However, taking into consideration the type of airmasses we`ll be under, along with climo for this time of year, the warmest days of the long-term period will be Sunday and Monday, with Saturday and Tuesday being slightly cooler, and Wednesday onward dropping well below normal. This forecast update will show highs in the upper 70s on Saturday as clouds and precip exit; highs in the lower 80s Sunday - Monday under southerly flow/WAA; Tuesday in the mid to upper 70s with stormy conditions; and 60s Wednesday - Thursday. Look for lows to respond accordingly with 60s Saturday night - Monday night and flirting with the 50 degree mark Tuesday night - Wednesday night. && .AVIATION (12Z TAF Update)... Issued at 635 AM EDT Fri May 9 2014 A surface cold front will push eastward toward the region today. Abundant high cloud cover will continue to advect eastward across the terminals today producing high ceilings. Scattered showers over western KY will continue to move east and may affect KSDF and KBWG by mid to late morning. Stronger aviation concern that will emerge this morning will be the increase in southwesterly winds at the terminals. We expect winds to pick up around 09/14Z or so with sustained winds of 12-16kts and gusts up to 20kts. Scattered convection is expected to further develop this afternoon and evening as the frontal boundary gets closer to the region. VFR conditions are expected to prevail at the terminals, but some temporary MVFR cigs within passing convection will be possible. Overall convective coverage should diminish toward sunset, but a secondary line of convection may develop out to the west and affect the terminals after 10/02Z. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........TWF Short Term.....MJ Long Term......BJS Aviation.......MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
926 AM EDT Fri May 9 2014 ...Forecast Update... Issued at 915 AM EDT Fri May 9 2014 An elongated axis of showers with a couple embedded bands of moderate to heavy rain and possibly an embedded elevated thunder- storm is moving northeast quickly this morning over west-central KY, now moving through our western forecast area. 06z model runs along with latest high-resolution HRRR model show that this axis should move steadily but coherently through our forecast area for the rest of this morning into early afternoon, before exiting to our east. Thus, have raised rainfall probabilities across our entire area. After this rain passes by, precip will end and then the question arises about what will happen later this afternoon. Still looks like some diurnal heating will commence with the atmosphere becoming more unstable. Models show that scattered convection could develop to our west this afternoon and then move east into our area later this afternoon and tonight. This scenario still seems reasonable, although am not able to pin things down more specifically at this time yet. Will continue to monitor trends through the day. No change to temperatures for today at this time. Will evaluate this later this morning into early afternoon. Issued at 640 AM EDT Fri May 9 2014 Did a quick update to back off PoPs a bit in the east this morning, but also increase PoPs slightly across our west and northwestern areas. Based on latest radar trends, expect a band of showers to affect portions of southern Indiana and Kentucky west of I-65 this morning. Expect this activity to diminish in intensity and coverage as it heads into a slightly drier and more stable airmass. Also backed off coverage this afternoon a bit given that overall model solutions are trending a bit drier. Likely PoPs appear to be too aggressive at this time and have backed them off into the scattered category. Also bumped temperatures in the west up slightly based on the assumption of lesser precipitation. .SHORT TERM (Now through Saturday)... Issued at 315 AM EDT Fri May 9 2014 In the near term, partly to mostly cloudy skies will be the rule across southern Indiana and central Kentucky this morning. Early morning IR imagery shows plenty of high level cloudiness streaming in from the west. Area radars are rather quiet across central KY but there are some returns back over southeastern Missouri that are heading eastward. We expect dry conditions for the remainder of the early morning hours. Temperatures remain quite mild with readings generally in the upper 60s to the lower 70s. Some of our cooler spots appear to have decoupled a bit and are seeing temperatures down into the upper 50s to around 60. We expect temperatures to slowly drop a few more degrees before rebounding towards sunrise. For Today, local and national high resolution modeling suggest area of convection across southeastern Missouri and northeastern Arkansas will grow upscale early this morning in response to a moderate low-level jet axis impinging northeastward into lower Mississippi Valley. This convection will work eastward during the morning hours and weaken a bit as it heads into central Kentucky. Persistent cloud cover and the remnants of this convective activity will likely keep instability down to marginal levels across the region. That is not to say that some areas may see stronger convection develop this afternoon. As the morning convection heads off to the east, we may see a few breaks develop which could lead to the development of pockets of higher instability during the afternoon. The best chances of this occurring would be out across the western areas. Overall, we still do not believe today will be a total washout. Though areas that do receive rain could get a nice soaking as the showers and storms move through the region. Highs today look to range from the middle to upper 70s in the west with upper 70s to lower 80s in the east. As we move into the evening hours, the higher resolution models do show a secondary line of storms forming along the frontal boundary approaching from the northwest. These storms probably will fire along a line from Indianapolis to St. Louis early this evening and then spread eastward into our region during the overnight period. Depending on how fast the early morning activity clears the region will be a determining factor in how strong the evening/overnight convection will be. With the line expected to come through at the time of minimum heating, we are not overly impressed with severe potential. Strong storms are certainly possible with damaging winds and hail being the primary threats. The activity should clear our region by early Saturday morning with temperatures only cooling into the mid-upper 60s. For Saturday, skies will likely start off mostly cloudy and then begin to clear from the west towards the east. While the upper flow takes on more of zonal pattern, there is difficulty in determining any real triggers for convection. Isolated-scattered convection will be possible with the highest concentration out toward the eastern portions of the forecast area. Though, by and large most areas will probably see mainly dry conditions. Highs for Saturday will be largely dependent on cloud cover during the afternoon. The multi-model consensus suggests highs in the upper 70s to near 80 in the west with mainly mid-upper 70s in the east. .LONG TERM (Saturday Night through Thursday)... Issued at 319 PM EDT Thu May 8 2014 As previously advertised, the Ohio Valley will be entering into an active pattern with showers and thunderstorms in the forecast for nearly every day in this period. Synoptically, Saturday will undergo a transition to more zonal at the 500mb level as the disturbance that brings rain to the region Friday night moves off toward the east. The forecast challenge for Saturday is how quickly the storms exit the forecast area as the deterministic models are struggling to come into better agreement. The trend has been just a bit slower, as evident from comparing previous runs with the 12Z runs. The NAM has been the quickest and conversely, the GFS messy and the slowest. The 09Z SREF seems to be the better compromise and have leaned toward it to show a general partial clearing from west to east throughout the day. Through the remainder of the weekend, much of Saturday night should be dry before the atmosphere recharges ahead of the next system. We`ll remain under southerly flow with high pressure centered over the Atlantic, allowing for GoMex moisture to pool into the region. Under this warm , moist air advection regime, Sunday`s forecast is also a bit tricky as we could see some sporadic storms firing up, especially with diurnal heating throughout the day. There is no obvious signal for which portions of the forecast area will see better rain chances than others given this type of setup so have broad brushed low-end chance PoPs throughout. After the sun sets on Sunday, should see a wane in storm coverage with the loss of the aforementioned heating. Something to watch for, however, is that the 12Z NAM is hinting at a mesoscale convective system to build across eastern KS/central MO and race off into the Great Lakes region late Saturday night through Sunday. This is in response to a surface low that develops just behind it. The NAM is depicting the eastern portion of this system to break off and jet across central KY before dying out as it loses its forcing mechanism. We`ll have to see how this evolves as we approach that time frame. As if the models haven`t been struggling enough, true temporal divergence becomes evident early next week as an amplified pattern sets up: troughing across the Plains and ridging over the East Coast. The GFS has been consistently fast with the ECMWF much slower. Have attempted to blend and compromise between the two, coming to the uncertain conclusion that Tuesday looks to be the best chance for active weather across the area. One thing the models do agree on is the pattern change coming by the middle to end of next week. Given the unsettled nature of the upcoming pattern, temperature forecasts will be difficult to nail down with certainty, with clouds potentially wrecking havoc on the highs/lows. However, taking into consideration the type of airmasses we`ll be under, along with climo for this time of year, the warmest days of the long-term period will be Sunday and Monday, with Saturday and Tuesday being slightly cooler, and Wednesday onward dropping well below normal. This forecast update will show highs in the upper 70s on Saturday as clouds and precip exit; highs in the lower 80s Sunday - Monday under southerly flow/WAA; Tuesday in the mid to upper 70s with stormy conditions; and 60s Wednesday - Thursday. Look for lows to respond accordingly with 60s Saturday night - Monday night and flirting with the 50 degree mark Tuesday night - Wednesday night. && .AVIATION (12Z TAF Update)... Issued at 635 AM EDT Fri May 9 2014 A surface cold front will push eastward toward the region today. Abundant high cloud cover will continue to advect eastward across the terminals today producing high ceilings. Scattered showers over western KY will continue to move east and may affect KSDF and KBWG by mid to late morning. Stronger aviation concern that will emerge this morning will be the increase in southwesterly winds at the terminals. We expect winds to pick up around 09/14Z or so with sustained winds of 12-16kts and gusts up to 20kts. Scattered convection is expected to further develop this afternoon and evening as the frontal boundary gets closer to the region. VFR conditions are expected to prevail at the terminals, but some temporary MVFR cigs within passing convection will be possible. Overall convective coverage should diminish toward sunset, but a secondary line of convection may develop out to the west and affect the terminals after 10/02Z. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........TWF/MJ Short Term.....MJ Long Term......BJS Aviation.......MJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
754 AM EDT FRI MAY 9 2014 .UPDATE... ISSUED AT 709 AM EDT FRI MAY 9 2014 UPDATED GRIDS FOR LATEST TRENDS...MAINLY IN RADAR RETURNS. SEEING AN OCCASIONAL 35 TO 45 DBZ ECHO WITHIN A BAND MOVING UP FROM THE SOUTHWEST. AT THAT STRENGTH EXPECT THERE SHOULD BE SOME LIGHT RAINFALL REACHING THE GROUND. MORE ISOLD CELLS ARE APPEARING FURTHER SOUTHWEST BUT MOVING NORTHEASTWARD AT A QUICK PACE. HRRR HAS A GOOD HANDLE ON THIS. BOTTOM LINE...BROUGHT POPS IN A BIT QUICKER THROUGH THE DAY. OTHERWISE, NO MAJOR CHANGES TO THE FORECAST ATTM. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 339 AM EDT FRI MAY 9 2014 FORECASTING THUNDER REMAINS A CHALLENGE AS THE LATEST RUN OF THE RAP HAS INCREASED SFC DEW POINTS CONSIDERABLY FROM JUST A FEW HOURS EARLIER FOR THIS AFTERNOON. STILL CAN NOT HELP BUT TO BELIEVE MODELS ARE OVER DOING MOISTURE BASED ON RECENT HISTORY IF NOTHING ELSE. EVEN THE NAM...WITH ITS TYPICALLY OVERDONE SFC DEW POINTS IS ADVERTISING NOTHING MORE THAN SCATTERED THUNDER. IN ADDITION...LATEST RUN OF THE HRRR SUGGEST THE STRONGEST CONVECTION WILL REMAIN SOUTH OF OUR AREA IN TN. HAVE DECIDED TO GO WITH JUST A CHANCE OF THUNDER FOR TODAY. WITH RELATIVELY DRIER BOUNDARY LAYER STILL EXPECT ANY SHOWERS AND/OR THUNDERSTORMS THAT DEVELOP WILL TEND TO BE HIGH BASED AND PRODUCE GUSTY WINDS. THE THREAT OF UNSETTLED WEATHER CONTINUES THROUGH THE REMAINDER OF THE SHORT TERM. HAVE NOTICED WITH THE LATEST MODEL RUNS THAT THE FRONTAL BOUNDARY BECOMES MORE DIFFUSE WITH TIME...EVEN TO THE POINT OF POSSIBLY WASHING OUT SOMEWHERE OVER THE REGION BY SATURDAY. WITH REMNANTS OF THE BOUNDARY IN THE AREA...AND BETTER SURFACE MOISTURE TO WORK WITH TONIGHT AND SATURDAY WILL GENERALLY MAINTAIN INHERITED POPS THROUGH THE PERIOD. OTHERWISE...NUDGED TEMPS TOWARDS LATEST BLEND OF MODEL/GUIDANCE. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 339 AM EDT FRI MAY 9 2014 A VERY UNCERTAIN LONG TERM PERIOD SETTING UP THROUGH NEXT WEEK. STRONG MID TO UPPER LEVEL RIDGING WILL REMAIN ANCHORED OVER THE EASTERN US THROUGH TUESDAY. HOWEVER...MODELS ARE SHOWING SOME SUBTLE WAVES PUSHING THROUGH THE RIDGE AXIS AT TIMES. FEEL THESE WAVES MAY BE OVER PRONOUNCED IN THE MODELS GIVEN THE IMPRESSIVE HEIGHTS OVER THE AREA. HOWEVER...GIVEN THE WARMTH...AND SLIGHTLY BETTER SFC MOISTURE INTO EARLY THIS WEEK...IT IS POSSIBLE WE COULD SEE A SHOWER OR THUNDERSTORM EACH AFTERNOON OR EARLY EVENING. CERTAINLY DOESN`T LOOK LIKE A WASH OUT BY ANY MEANS...BUT THE SMALL THREAT IS THERE. IT APPEARS THE BETTER CHANCES FOR SHOWERS AND STORMS WILL COME MIDWEEK AS A STRONG COLD FRONT MARCHES EAST ACROSS THE AREA. MODELS REMAIN IN STARK CONTRAST WITH REGARDS TO TIMING THIS FEATURE ACROSS THE AREA...SO HAVE GONE WITH A PERIOD OF HIGHER POPS FROM TUESDAY NIGHT THROUGH WEDNESDAY EVENING. MOST LIKELY THE PERIOD OF UNSETTLED WEATHER WILL BE MUCH MORE NARROW THAN THIS WINDOW. IT DOES APPEAR THE WEATHER SHOULD TURN COOL AND DRIER BY THURSDAY...BUT AN UPPER LEVEL TROUGH MAY BRING SOME UNSETTLED WEATHER BACK TO THE AREA BY WEEKS END. GIVEN THE UNCERTAINTY WITH PRECIPITATION CHANCES THIS WEEK...HAVE GONE WITH ASSUMPTION...MOST DAYS WILL FEATURE DRY WEATHER AND THUS...WARMER TEMPERATURES...AT LEAST THROUGH TUESDAY. BY WEDNESDAY...TEMPERATURES WILL START TO TAKE A STEP DOWNWARDS...AND CERTAINLY BY WEDNESDAY WITH HIGHS LIKELY BACK INTO THE 60S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 754 AM EDT FRI MAY 9 2014 IN GENERAL EXPECTING VFR CONDITIONS THROUGH THE ENTIRE FORECAST PERIOD. RADAR SHOWING SOME ISOLATED SHOWERS ALREADY ENTERING THE AREA THIS MORNING. MORE SCATTERED SHOWERS TO THE SOUTHWEST...AND A LARGER BAND OF RAIN WHICH WILL BE MOVING INTO THE AREA AS THE DAY PROGRESSES. FORECAST SOUNDINGS NOT THE MOST FAVORABLE FOR THUNDER TODAY WITH RELATIVELY DRY LOWER LEVELS AND MOSTLY CLOUDY SKIES HELPING TO KEEP TEMPERATURES...SURFACE BASED INSTABILITY DOWN A BIT. BUT CAN NOT RULE OUT THUNDER ALTOGETHER. FOR NOW PLAYED DOWN THUNDER IN THE TAFS UNTIL TONIGHT WHERE SOUNDINGS LOOK MORE UNSTABLE GOING INTO SATURDAY MORNING DUE TO A SURFACE FRONTAL BOUNDARY MAKING AN HONEST PUSH TOWARDS OUR AREA AND AS MOISTURE INCREASES AT THE SURFACE AHEAD OF THIS SYSTEM. FOR NOW IT APPEARS THIS FRONT WILL STALL AND WASH OUT SOMETIME SATURDAY. WINDS WILL GENERALLY INCREASE FROM THE SOUTH...SOUTHWEST AT 10-15 KTS THROUGH THE DAY WITH AN OCCASIONAL HIGHER GUST. HOWEVER...WITH RELATIVELY DRIER LOW LEVELS WINDS COULD BE VARIABLE AND GUSTY AROUND ANY SHOWERS AND THUNDERSTORMS THAT DO DEVELOP. GUSTY WIND THREAT ASSOCIATED WITH SHOWERS AND ANY THUNDERSOTRMS WILL ABATE AS RAINFALL MOISTENS UP THE LOWER LEVELS. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...RAY LONG TERM...KAS AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
709 AM EDT FRI MAY 9 2014 .UPDATE... ISSUED AT 709 AM EDT FRI MAY 9 2014 UPDATED GRIDS FOR LATEST TRENDS...MAINLY IN RADAR RETURNS. SEEING AN OCCASIONAL 35 TO 45 DBZ ECHO WITHIN A BAND MOVING UP FROM THE SOUTHWEST. AT THAT STRENGTH EXPECT THERE SHOULD BE SOME LIGHT RAINFALL REACHING THE GROUND. MORE ISOLD CELLS ARE APPEARING FURTHER SOUTHWEST BUT MOVING NORTHEASTWARD AT A QUICK PACE. HRRR HAS A GOOD HANDLE ON THIS. BOTTOM LINE...BROUGHT POPS IN A BIT QUICKER THROUGH THE DAY. OTHERWISE, NO MAJOR CHANGES TO THE FORECAST ATTM. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 339 AM EDT FRI MAY 9 2014 FORECASTING THUNDER REMAINS A CHALLENGE AS THE LATEST RUN OF THE RAP HAS INCREASED SFC DEW POINTS CONSIDERABLY FROM JUST A FEW HOURS EARLIER FOR THIS AFTERNOON. STILL CAN NOT HELP BUT TO BELIEVE MODELS ARE OVER DOING MOISTURE BASED ON RECENT HISTORY IF NOTHING ELSE. EVEN THE NAM...WITH ITS TYPICALLY OVERDONE SFC DEW POINTS IS ADVERTISING NOTHING MORE THAN SCATTERED THUNDER. IN ADDITION...LATEST RUN OF THE HRRR SUGGEST THE STRONGEST CONVECTION WILL REMAIN SOUTH OF OUR AREA IN TN. HAVE DECIDED TO GO WITH JUST A CHANCE OF THUNDER FOR TODAY. WITH RELATIVELY DRIER BOUNDARY LAYER STILL EXPECT ANY SHOWERS AND/OR THUNDERSTORMS THAT DEVELOP WILL TEND TO BE HIGH BASED AND PRODUCE GUSTY WINDS. THE THREAT OF UNSETTLED WEATHER CONTINUES THROUGH THE REMAINDER OF THE SHORT TERM. HAVE NOTICED WITH THE LATEST MODEL RUNS THAT THE FRONTAL BOUNDARY BECOMES MORE DIFFUSE WITH TIME...EVEN TO THE POINT OF POSSIBLY WASHING OUT SOMEWHERE OVER THE REGION BY SATURDAY. WITH REMNANTS OF THE BOUNDARY IN THE AREA...AND BETTER SURFACE MOISTURE TO WORK WITH TONIGHT AND SATURDAY WILL GENERALLY MAINTAIN INHERITED POPS THROUGH THE PERIOD. OTHERWISE...NUDGED TEMPS TOWARDS LATEST BLEND OF MODEL/GUIDANCE. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 339 AM EDT FRI MAY 9 2014 A VERY UNCERTAIN LONG TERM PERIOD SETTING UP THROUGH NEXT WEEK. STRONG MID TO UPPER LEVEL RIDGING WILL REMAIN ANCHORED OVER THE EASTERN US THROUGH TUESDAY. HOWEVER...MODELS ARE SHOWING SOME SUBTLE WAVES PUSHING THROUGH THE RIDGE AXIS AT TIMES. FEEL THESE WAVES MAY BE OVER PRONOUNCED IN THE MODELS GIVEN THE IMPRESSIVE HEIGHTS OVER THE AREA. HOWEVER...GIVEN THE WARMTH...AND SLIGHTLY BETTER SFC MOISTURE INTO EARLY THIS WEEK...IT IS POSSIBLE WE COULD SEE A SHOWER OR THUNDERSTORM EACH AFTERNOON OR EARLY EVENING. CERTAINLY DOESN`T LOOK LIKE A WASH OUT BY ANY MEANS...BUT THE SMALL THREAT IS THERE. IT APPEARS THE BETTER CHANCES FOR SHOWERS AND STORMS WILL COME MIDWEEK AS A STRONG COLD FRONT MARCHES EAST ACROSS THE AREA. MODELS REMAIN IN STARK CONTRAST WITH REGARDS TO TIMING THIS FEATURE ACROSS THE AREA...SO HAVE GONE WITH A PERIOD OF HIGHER POPS FROM TUESDAY NIGHT THROUGH WEDNESDAY EVENING. MOST LIKELY THE PERIOD OF UNSETTLED WEATHER WILL BE MUCH MORE NARROW THAN THIS WINDOW. IT DOES APPEAR THE WEATHER SHOULD TURN COOL AND DRIER BY THURSDAY...BUT AN UPPER LEVEL TROUGH MAY BRING SOME UNSETTLED WEATHER BACK TO THE AREA BY WEEKS END. GIVEN THE UNCERTAINTY WITH PRECIPITATION CHANCES THIS WEEK...HAVE GONE WITH ASSUMPTION...MOST DAYS WILL FEATURE DRY WEATHER AND THUS...WARMER TEMPERATURES...AT LEAST THROUGH TUESDAY. BY WEDNESDAY...TEMPERATURES WILL START TO TAKE A STEP DOWNWARDS...AND CERTAINLY BY WEDNESDAY WITH HIGHS LIKELY BACK INTO THE 60S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 205 AM EDT FRI MAY 9 2014 LOOKING AT VFR CONDITIONS THROUGH THE ENTIRE FORECAST PERIOD. MAIN CHALLENGE TO THE AVIATION FORECAST WILL BE THE POTENTIAL FOR THUNDERSTORMS LATER TODAY. THINGS DO NOT LOOK REAL IMPRESSIVE BASED ON LATEST FORECAST SOUNDINGS. BELIEVE MODELS...NAM/GFS ARE OVERDOING SFC MOISTURE AGAIN AND CONSEQUENTLY SFC BASED INSTABILITY. SOUNDINGS ALSO HAVE THE FAMILIAR INVERTED V PROFILE TYPICALLY SEEN IN THE WESTERN CONUS. THOUGHTS ARE THAT WE MAY CUT BACK ON PROBABILITY OF THUNDER...FROM LIKELY TO CHANCE. HOWEVER...WITH DIRER LOWER LEVELS THIS ALSO MEANS THAT ANY SHOWERS THAT DEVELOP WILL TEND TO BE HIGH BASED AND PRODUCE GUSTY WINDS DUE TO THE ADDITIVE MOMENTUM OF EVAPORATIVE COOLING OF RAINFALL. LIGHT AND VARIABLE WILL INCREASE FROM THE SOUTH...SOUTHWEST AT 10 TO 15 KTS BY MIDDAY FRIDAY. A FEW GUSTS TO 20 KTS WILL BE POSSIBLE LATE IN THE DAY FRIDAY. AGAIN... WINDS COULD BE QUITE VARIABLE AND GUSTY AROUND ANY SHOWERS AND THUNDERSTORMS THAT MAY DEVELOP. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...RAY LONG TERM...KAS AVIATION...RAY
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1035 AM CDT FRI MAY 9 2014 .UPDATE... ISSUED AT CDT FRI MAY 9 2014 THE FOCUS FOR THIS UPDATE WAS THE DENSE FOG OVER WESTERN LAKE SUPERIOR AND AREAS ALONG THE NORTH AND SOUTH SHORE...AS WELL AS THE RAIN SHOWERS FOR TODAY AND THIS EVENING. THE MODELS ARE SUGGESTING THE FOG WILL LINGER ALONG THE NORTH SHORE LONGEST...PROBABLY TILL MID AFTERNOON...SO I EXTENDED THE DENSE FOG ADVISORY FOR THE NORTH SHORE UNTIL 3 PM. THE HRRR SEEMED TO BE DOING FAIRLY WELL WITH THE CURRENT COVERAGE OF DENSE FOG...SO I LEANED ON THE HRRR FOR THE AFTERNOON FORECAST. THE FOG NEAR THE TWIN PORTS SHOULD BEGIN TO LIFT VERY LATE THIS MORNING...SO I ONLY EXTENDED THAT PART OF THE ADVISORY TILL NOON. THE NORTHWEST WINDS DEVELOPING BEHIND THE PASSING LOW PRESSURE SYSTEM WILL ALSO BE HELPING TO DISSIPATE THE FOG. WE MAY HAVE HAD PCPN ENDING TOO QUICKLY...AND DID NOT HAVE HIGH ENOUGH PCPN CHANCES ACROSS THE NORTHERN FORECAST AREA. THE MODELS ARE IN GOOD AGREEMENT WITH THE PCPN LINGERING LONGER THAN THE PREVIOUS FORECAST...SO I DELAYED ITS DISSIPATION AND/OR EXIT FROM THE FORECAST AREA THROUGH THIS EVENING. UPDATE ISSUED AT 620 AM CDT FRI MAY 9 2014 UPDATED FOR AVIATION DISCUSSION. && .SYNOPSIS... ISSUED AT 354 AM CDT FRI MAY 9 2014 SURFACE LOW CURRENTLY JUST NORTHEAST OF KSTL IS GRADUALLY MOVING NORTHEAST...WITH SOME FAIRLY STRONG PRESSURE FALLS AND AN INVERTED TROUGH OVER THE ARROWHEAD THIS MORNING. EXTENDING FROM CENTRAL WISCONSIN UP OVER WESTERN UPPER MICHIGAN AND LAKE SUPERIOR IS A BAND OF SHOWERS AND THUNDERSTORMS THAT MOVED OVER THE FORECAST AREA OVERNIGHT. OVER WESTERN MINNESOTA...EASTERN NORTH AND SOUTH DAKOTA IS AN AREA OF RAIN SHOWERS IN THE WRAP AROUND PORTION OF THE STORM...ACCOMPANIED BY A NICE PV ANOMALY INDICATIVE OF A TROWAL. THE SURFACE WARM FRONT EXTENDS EAST FROM THE SURFACE LOW ALONG THE DEWPOINT DISCONTINUITY OVER NORTHERN WISCONSIN AND INTO UPPER MICHIGAN. THE COLD FRONT EXTENDS SOUTH FROM THE LOW...AND IS PLOWING EAST ACROSS IOWA AND MISSOURI. IN THE CONVERGENT AREA AHEAD OF THE SURFACE LOW WHERE WINDS ARE LIGHT AND DEWPOINT DEPRESSIONS ARE LOW...AREAS OF FOG HAVE DEVELOPED. IT SEEMS MOST WIDESPREAD WHERE SOME OF THE COOLER MARINE LAYER HAS SLOPPED ASHORE IN THE LIGHT NORTHEAST FLOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 354 AM CDT FRI MAY 9 2014 THE SURFACE LOW WILL CONTINUE TO MOVE NORTHEAST TODAY...EXITING TO CENTRAL ONTARIO BY 18Z TODAY. THE AREAS OF DENSE FOG MENTIONED ABOVE HAVE BEEN PERSISTENT MOST OF THE NIGHT AHEAD OF THE LOW...AND HAVE DECIDED TO ISSUE A DENSE FOG FOR THE NORTH SHORE AND AREAS AROUND THE HEAD OF THE LAKE UNTIL MID MORNING. AS THE SURFACE LOW MOVES ACROSS THE AREA THE WIND DIRECTION WILL TURN AROUND TO THE NORTHWEST...SOME DRIER AIR WILL BEGIN TO WORK INTO THE AREA EVEN IF TEMPERATURES DONT CHANGE MUCH...SO EXPECT THE FOG TO DISSIPATE BY MID MORNING. THE SHOWERS THIS MORNING OVER THE FAR NORTHEASTERN CWA SHOULD MOVE OFF TO THE EAST...LEAVING THAT PART OF THE FORECAST AREA MOSTLY DRY. THE AREA OF SHOWERS ASSOCIATED WITH THE TROWAL ARE GOING TO SWEEP ACROSS THE FORECAST AREA TODAY AND EARLY THIS EVENING...MAINLY OVER NORTHERN MINNESOTA. AM FAIRLY CONFIDENT IN THIS AREA OF PRECIPITATION...SO HAVE RAISED POPS SOMEWHAT AND REFINED TIMING SOMEWHAT. UNDER THIS AREA OF SHOWERS TEMPERATURES ARE GOING TO ONLY GET INTO THE UPPER 40S TO AROUND 50...WITH HIGHS IN THE MID TO UPPER 50S MOST OTHER LOCATIONS. TEMPERATURES EARLY THIS MORNING ARE IN THE UPPER 50S TO LOWER 60S OVER PORTIONS OF NORTHWEST WISCONSIN WHERE THEY ARE IN THE WARM SECTOR. EXPECT THAT THEY ARE AT OR NEAR THEIR HIGHS FOR TODAY...AND WILL ONLY REMAIN STEADY OR SLOWLY FALL THE REST OF THE DAY. TONIGHT THE SHOWERS WILL STILL BE AFFECTING THE ARROWHEAD REGION IN THE EVENING...BUT A THERE WILL BE A GRADUAL CLEARING TREND SETTING UP FROM SOUTHWEST TO NORTHEAST AS THE STORM GRADUALLY MOVES OFF TO THE NORTHEAST TONIGHT. EXPECT TEMPERATURES TO FALL OFF INTO THE MID 30S MOST LOCATIONS...AS I EXPECT CLEARING TO OCCUR FOR NEARLY THE WHOLE CWA BY EARLY MORNING. WINDS WILL DROP OFF ENOUGH FOR RADIATIONAL COOLING TO BE FAIRLY SIGNIFICANT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 354 AM CDT FRI MAY 9 2014 A NARROW RIDGE OF HIGH PRESSURE ALOFT AND AT THE SURFACE WILL BUILD IN SAT MORNING WITH DRY CONDITIONS AND MOSTLY SUNNY SKIES THROUGH MOST OF THE DAY. A WEAK UPPER S/W AND ASSOCIATED SFC TROUGH WILL LIFT E/NEWD FROM THE DAKOTAS INTO MN AND WRN LAKE SUPERIOR LATER IN THE DAY SATURDAY AND ESPECIALLY SAT NIGHT. THIS SYSTEM WILL PRODUCE ANOTHER ROUND OF WIDESPREAD RAIN SHOWERS AND A FEW WEAK THUNDERSTORMS. THE SFC BOUNDARY WILL STALL OUT AS IT LIFTS NWD INTO NRN MN AND AWAIT THE NEXT SURGE OF WARM MOIST AIR LATE IN THE WEEKEND...ALONG WITH THE NEXT LOW PRESSURE SYSTEM EXPECTED TO TRACK SW TO NE OVER THE UPPER MIDWEST MON INTO TUE MORNING. THIS SYSTEM WILL ONCE AGAIN BE LOADED WITH MOISTURE AND ALSO DRAW UP A SLIGHTLY UNSTABLE AIR MASS TO PRODUCE ISOLATED THUNDERSTORMS AND THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. AS THE SFC LOW APPROACHES FROM THE SW...PRESSURE FALLS WILL INDUCE A STRONG NE FLOW OFF LAKE SUPERIOR AND COMBINE WITH FAIRLY STRONG WAA IN THE MID/LOW LVLS TO PRODUCE ANOTHER PERIOD OF COOL/CLOUDY/FOGGY CONDITIONS AROUND THE PERIPHERY OF THE LAKE. THE PRESENCE OF THIS COOL/STABLE NEAR-SFC LAYER WILL KEEP ANY STORMS ELEVATED THAT TRACK TO THE NORTH...KEEPING THE THREAT OF STRONG/SEVERE WX ON THE LOW SIDE. AN UNSEASONABLY COLD AIR MASS WILL ADVECT IN ON THE BACK SIDE OF THIS SYSTEM AS IT DEPARTS TO THE EAST LATE TUE AND WED. THE AIR PUSHING IN FROM THE NW COULD BE COLD ENOUGH TO ALLOW FOR A FEW LIGHT SNOW SHOWERS TO MIX IN LATE TUE NIGHT...AND AGAIN LATE WED NIGHT. 850MB TEMPS WILL BE ROUGHLY -5 TO -10 DEG C. YES IT IS ALMOST THE MIDDLE OF MAY. WILL SEE SLIGHT IMPROVEMENT INTO THURSDAY AS HIGH PRESSURE GRADUALLY BUILDS IN ACROSS THE MIDWEST. HOWEVER IT WILL NOT BE UNTIL THE WEEKEND UNTIL TEMPS REACH BACK TO NEAR NORMAL. TEMPERATURES THIS WEEKEND WILL BE AT OR SLIGHTLY ABOVE NORMAL WITH LIGHT AND VARIABLE WINDS. SATURDAY WILL LIKELY BE THE MOST PLEASANT DAY WITH DRY CONDITIONS EXPECTED. THE TEMP TREND WILL BEGIN A DOWNWARD SLIDE MON THROUGH WED WITH HIGHS IN THE 40S AND 50S AND OVERNIGHT LOWS IN THE 30S. A GRADUAL WARMING TREND WILL NOT BE FELT UNTIL THE LATTER HALF OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 620 AM CDT FRI MAY 9 2014 LIFR CIGS AND VSBYS WILL PERSIST THIS MORNING WITH GRADUAL IMPROVEMENT THROUGH THE AFTERNOON AS THE LOW PRESSURE SYSTEM LIFTS NEWD ACROSS THE NORTHLAND. WILL SEE A BAND OF RAIN SHOWERS ON THE BACK SIDE OF THIS SYSTEM ROTATE EWD THROUGH THE REGION THIS MORNING AND INTO THE AFTERNOON...TAPERING OFF WEST TO EAST. CIGS WILL LIFT TO MVFR AND EVENTUALLY VFR THIS AFTERNOON...WITH CLEARING SKIES W-E EXPECTED THIS EVENING AND TONIGHT. WINDS ROTATING AROUND THE SFC LOW TODAY WILL BE GUSTY...UP TO 15 TO 25 KNOTS. WINDS WILL DIMINISH TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 51 37 63 48 / 60 40 10 60 INL 50 34 67 44 / 80 40 0 50 BRD 55 36 64 46 / 70 10 40 50 HYR 57 38 67 47 / 70 30 10 50 ASX 56 38 64 45 / 40 40 0 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...DENSE FOG ADVISORY UNTIL NOON CDT TODAY FOR MNZ037. DENSE FOG ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR MNZ020-021. WI...DENSE FOG ADVISORY UNTIL NOON CDT TODAY FOR WIZ001. LS...SMALL CRAFT ADVISORY UNTIL 4 AM CDT SATURDAY FOR LSZ143>147. DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR LSZ144-145. DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR LSZ142-143. DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ140-141. && $$ UPDATE...GROCHOCINSKI SYNOPSIS...LE SHORT TERM...LE LONG TERM...BJT AVIATION...BJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
600 AM CDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT FRI MAY 9 2014 RAP ANALYZED SURFACE LOW JUST SOUTH OF DULUTH EARLY THIS MORNING. AREAS WEST OF THE METRO HAVE SEEN THE WINDS TURN WESTERLY AND PICK UP IN INTENSITY. COLD AIR ADVECTION IS ONGOING IN THESE AREAS...AND WILL CONTINUE TO SPREAD ACROSS THE REMAINDER OF THE FORECAST AREA TODAY. THE SURFACE LOW WILL SLOWLY CONTINUE NORTHEASTWARD...AS THE WESTERLY WINDS TAKE MUCH OF THE DAY TO SPREAD ACROSS WEST CENTRAL WISCONSIN. ABUNDANT LOW LEVEL MOISTURE WILL ALLOW FOR LOW LCL HEIGHTS WHICH IS CURRENTLY NOTICEABLE IN THE OBSERVATIONS BEHIND THE COLD FRONT WHERE CEILINGS UNDER 1K FEET ARE PRESENT. RAP AND NAM MODEL SOUNDINGS INDICATE THIS MOISTURE STICKING AROUND FOR MUCH OF THE DAY...SO TRENDED TOWARD A MORE PESSIMISTIC SKY COVER FORECAST AND HENCE LOWERED MAX TEMPERATURES TODAY BY A FEW DEGREES ACROSS THE FA. MAX TEMPS WILL BE ABOUT 10 DEGREES BELOW SEASONAL NORMALS FOR THIS TIME OF YEAR. IN ADDITION...WRAP AROUND LIGHT RAIN SHOWERS ARE EXPECTED TO MOVE ACROSS THE NORTHERN PORTION OF THE CWA AS THEY CYCLONIC CIRCULATION ALOFT REMAINS BETTER TOWARD THE NORTH /AS WELL AS AT LEAST SOME FGEN AND FN VECTOR CONVERGENCE/. SKIES WILL BEGIN CLEARING LATE THIS AFTERNOON AND MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT...EXCEPT CLOUDS WILL QUICKLY BEGIN FILLING IN FROM THE SOUTHWEST EARLY SATURDAY MORNING. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 340 AM CDT FRI MAY 9 2014 AN UNSETTLED PERIOD REMAINS FORECAST FOR MUCH OF THE LONGER TERM AS NORTHERN AND SOUTHERN STREAM ENERGY EVENTUALLY PHASE OVER THE CENTER OF THE COUNTRY AROUND THE MIDDLE OF NEXT WEEK. THIS PROCESS OCCURS THE FASTEST WITH THE GFS WHILE DP/DT SHOWS THAT THE SLOWER ECMWF IS BECOMING EVEN SLOWER WITH TIME. ON SATURDAY...A WAVE MOVING IN FROM THE CENTRAL PLAINS WILL BRING THICKENING CLOUDINESS AND SHOWERS BACK ACROSS THE FA FROM SW TO NE DURING THE DAY. A BRIEF BREAK IN THE PRECIPITATION IS EXPECTED SATURDAY NIGHT BEFORE A MORE POTENT WAVE BEGINS TO TAKE SHAPE OVER THE CENTRAL PLAINS ON SUNDAY. THIS WAVE IS BEING DRIVEN BY THE SOUTHERN STREAM ENERGY. USING THE SLOWER ECWMF...THE LOW IN THE PLAINS TAKES UNTIL MONDAY EVENING TO ARRIVE IN SE MN. THIS PLACES MUCH OF THE FA IN LOW LEVEL THETA-E ADVECTION FROM SUNDAY THROUGH MONDAY...WITH SOUTHERN MN BEARING THE BRUNT OF IT. HENCE...LIKELY POPS STREAM BACK IN ON SUNDAY FROM THE SOUTHWEST AND PERSIST THROUGH MONDAY. WIDESPREAD HALF INCH TO ONE INCH RAINFALL IS LIKELY DURING THIS PERIOD WITH SOME TWO INCH AMOUNTS OVER SOUTHERN MN. THERE WILL CERTAINLY BE THE THREAT FOR SOME THUNDERSTORMS...ESPECIALLY ON MONDAY FROM THE TWIN CITIES ON EAST AND SOUTH. STRICTLY USING THE ECMWF TIMING WOULD INDICATE A WINDOW OF OPPORTUNITY FOR STRONG TO SEVERE STORMS MONDAY AFTERNOON/EVENING TO THE SOUTH AND EAST OF THE TWIN CITIES. THE SHOWERS WILL BEGIN TO TAPER OFF MONDAY NIGHT AS THE LOW PRESSURE SYSTEM MOVES NORTHEAST OF THE FA. INSTABILITY SHOWERS ARE POSSIBLE MAINLY FROM CENTRAL MINNESOTA ON NORTHWARD ON TUESDAY. SCATTERED SHOWERS ARE BACK FOR MUCH OF THE FA WEDNESDAY AND THURSDAY AS THE UPPER TROUGH COMES TOGETHER FROM THE UPPER MISSISSIPPI VALLEY TO THE GULF COAST. HIGH TEMPERATURES WILL BE CLOSE TO NORMAL THIS WEEKEND...BUT THEN RETREAT TO SOME 10 TO 15 DEGREES BELOW NORMAL FOR THE MIDDLE TO END OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 547 AM CDT FRI MAY 9 2014 LOW PRESSURE CENTER LIFTING NORTHEAST TOWARD LAKE SUPERIOR...LEAVING A SOLID LOW STRATUS DECK ACROSS MINNESOTA AND WESTERN WISCONSIN. MODELS HAVE BECOME MORE PESSIMISTIC OVER THE LAST 2 RUNS IN HANDLING THIS MOISTURE...AND CLOSELY FOLLOWED UPDATED GUIDANCE TO HOLD CIGS IN THE IFR/MVFR RANGE FOR MOST OF TODAY...WITH PERIODS OF LIFR POSSIBLE. THERE HAS BEEN SOME PATCHY FOG THROUGH THE OVERNIGHT HOURS...WHICH HAS BEEN HARD TO PIN DOWN BECAUSE IT IS WIDELY SCATTERED. THE CEILINGS HAVE BEEN BOUNCING A BIT...ESPECIALLY AT EASTERN SITES. BOTH RAP AND NAM STILL INDICATE LOW CIGS WITH GRADUAL LIFTING. SCATTERED SHOWERS WILL ROTATE THROUGH THE NORTHERN HALF OF THE CWA. WINDS WILL REMAIN WESTERLY AND CONTINUE GUSTING TODAY. SKIES WILL CLEAR OUT TONIGHT...AND WINDS WILL BECOME LIGHT AND VARIABLE FOR A TIME. KMSP...IFR CIGS WITH POSSIBLY LIFR AT TIMES WILL CONTINUE THIS MORNING. IT LOOKS LIKE THE SCATTERED SHOWERS WILL SIDE SWIPE THE TERMINAL...SO MAY STAY COMPLETELY DRY...BUT DID FEEL INCLINED TO INCLUDE A MENTION OF LIGHT PRECIPITATION TODAY. /OUTLOOK FOR KMSP/ SAT...VFR. CHC -TSRA. WINDS SSE 10KTS. SUN...MVFR POSSIBLE. LIKELY -SHRA. WINDS SW TO NW 10-15 KTS. MON...MVFR POSSIBLE. LIKELY -SHRA. WINDS NW 10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...SPD LONG TERM...RAH AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TULSA OK
1026 AM CDT FRI MAY 9 2014 ...UPDATE... .DISCUSSION... A COLD FRONT WAS POSITIONED NEAR A LINE FROM GROVE TO JUST SOUTH OF TULSA TO NEAR OKEMAH LATE THIS MORNING. BEHIND THE FRONT...NORTHERLY WINDS AND PARTLY CLOUDY SKIES WERE BEING OBSERVED. AHEAD OF THE FRONT...LOW CEILINGS WERE COMMON ACROSS THE MAJORITY OF EASTERN OKLAHOMA AND NORTHWEST ARKANSAS. ALSO SOME PATCHY AREAS OF LIGHT DRIZZLE HAVE BEEN REPORTED WITHIN THE LOW CLOUDS THIS MORNING. A CHANCE OF A SHOWER AND OR A THUNDERSTORM WILL ALSO BE POSSIBLE...MAINLY ACROSS FAR NORTHWEST ARKANSAS THROUGH THE MORNING HOURS AHEAD OF THE FRONT. THE COLD FRONT WILL CONTINUE ITS EASTWARD MOVEMENT INTO THE AFTERNOON HOURS AND IS EXPECTED TO STALL ACROSS SOUTHEAST OKLAHOMA INTO NORTHWEST ARKANSAS FOR THE LATE AFTERNOON/EVENING HOURS. SKIES SHOULD CONTINUE TO SCATTER OUT BEHIND THE FRONT AND BECOME PARTLY CLOUDY AHEAD OF THE FRONT...ALLOWING TEMPS TO GET INTO THE 70S TO LOW 80 FROM NORTH TO SOUTH. DIURNAL HEATING AND INSTABILITY AHEAD OF THE FRONT WILL ALLOW FOR AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS THROUGH THE EVENING HOURS. THOUGH...LATEST HRRR AND LOCAL IN-HOUSE MODEL RUNS ARE DEVELOPING ACTIVITY JUST TO THE EAST OF THE CWA THIS AFTERNOON. ANY THUNDERSTORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO BECOME STRONG TO SEVERE...WITH LARGE HAIL/STRONG WINDS BEING THE MAIN HAZARDS. FOR MORNING UPDATE...WILL CONTINUE THE SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE EAST THIS AFTERNOON AND WILL ADD PATCHY DRIZZLE THROUGH THE LATE MORNING HOURS AHEAD OF THE FRONT. HAVE ALSO TWEAKED SKY GRIDS AND WILL MONITOR TEMPS THROUGH THE AFTERNOON FOR ANY ADDITIONAL UPDATES. && .PRELIMINARY POINT TEMPS/POPS... TUL 77 62 90 72 / 10 10 20 20 FSM 81 63 87 69 / 20 10 30 20 MLC 81 64 86 71 / 10 10 20 10 BVO 76 58 90 68 / 10 10 30 20 FYV 76 58 83 67 / 20 10 30 20 BYV 76 58 83 67 / 30 10 30 30 MKO 78 61 88 70 / 10 10 20 20 MIO 75 58 87 69 / 30 10 30 30 F10 78 63 88 70 / 10 10 20 20 HHW 84 65 86 70 / 10 20 20 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...20
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1028 AM CDT FRI MAY 9 2014 .DISCUSSION... RADAR COMPOSITES THIS MORNING SHOWING SHOWERS AND THUNDERSTORMS PRETTY MUCH SURROUNDING THE FORECAST AREA...WITH CLUSTERS TO THE NORTHEAST AND SOUTHWEST...AND SOME STRONG TO SEVERE CELLS OFF TO THE WEST OF SAN ANTONIO. MORNING SOUNDINGS AND MODEL FORECAST SOUNDING SUGGEST CURRENTLY WEAKLY CAPPED ATMOSPHERE SHOULD BECOME UNSTABLE THIS AFTERNOON...ASSUMING CLOUD COVER ERODES AS EXPECTED AND TEMPS RISE INTO THE MID 80S. SHOULD THAT MATERIALIZE...LOOKING AT CAPE VALUES ABOVE 3000 J PER KG...ESPECIALLY NW ZONES. SHEAR PROFILES SHOW ZERO TO 6 KM VALUES IN THE 20 TO 30 KNOT RANGE. WITH MODERATE INSTABILITY AND SHEAR...AND DRIER AIR ALOFT...EXPECT MULTICELLS LIKELY THE DOMINANT CONVECTIVE MODE...WITH SOME POTENTIAL FOR ISOLATED DOWNBURST WINDS AND HAIL BEING THE MAIN THREATS. LOW LEVEL SHEAR NOT VERY STRONG...SO TORNADOES NOT LIKELY. && .MARINE... SE WINDS OF 10-15 KNOTS TODAY. TROPICAL TAP OF MOISTURE FROM THE PACIFIC IS DRAPED OVER MEXICO AND THE COASTAL WATERS. THE NORTHERN PERIPHERY OF THE MOISTURE MAY EXTEND OVER THE BAYS. THIS ABUNDANT MOISTURE AND NOISY SW-WSW FLOW ALOFT SHOULD KEEP THE MARINE ENVIRONMENT ACTIVE WITH SHOWERS AND THUNDERSTORMS TODAY...ESPECIALLY IF ANY BREAKS FORM. 45 && .AVIATION... CIGS GRADUALLY RISING WITH MOSTLY MVFR (1500-2000FT) AT 15Z THOUGH CLL/UTS WERE VFR CIGS BUT STILL HAVE SOME HAZE. EXPECT THAT ACROSS THE AREA WE WILL CONTINUE TO SEE CIGS RISE AND BREAKS DEVELOP SO BKN TO SCT VFR CIGS CAN BE EXPECTED FOR HOU/IAH NORTHWARD BY 19Z...IF NOT SOONER. GIVEN THE POOR MODEL CONSENSUS AND POOR INITIALIZATION OF CONVECTION TO THE WEST ANY TIMING FOR ONSET OF SHRA/TSRA IN THE SETX TERMINALS IS LOW CONFIDENCE. THOUGH THE ENVIRONMENT IS RIPE THIS AFTERNOON PERHAPS PEAK HEATING AND THE ARRIVAL OF S/W NEAR DRT MAY BE ENOUGH TO OVERCOME THE SMALL CAP THIS AFTERNOON. ANY THAT DO FORM SHOULD BE CAPABLE OF STRONG GUSTY WINDS AND POSSIBLY AND CAN`T RULE OUT SOME SMALL HAIL THOUGH THAT MAY BE CONFINED TO AREAS WEST OF A BYY-CLL LINE. 45 .PREV DISCUSSION... /ISSUED 638 AM CDT FRI MAY 9 2014/ DISCUSSION... SEE THE 12Z AVIATION DISCUSSION BELOW. 40 AVIATION... IFR TO MVFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE MORNING. THE MODELS ARE INDICATING POSSIBLE VFR DURING THE MID OR LATE AFTERNOON PERIOD. BEST CHANCES FOR SHOWERS OR THUNDERSTORMS WILL BE AT KCLL AND KUTS. HOWEVER...GIVEN THE MOISTURE CHANNEL OVER THE GULF...THERE IS A SLIGHT CHANCE OF SHOWERS FROM KHOU TO THE COAST THROUGH 15Z. MAY AMEND IF MORE SHOWERS THAN EXPECTED DEVELOP. THIS EVENING...MODEL SOUNDINGS INDICATE MVFR TO IFR CONDTIONS WILL DEVELOP. 40 PREV DISCUSSION... /ISSUED 333 AM CDT FRI MAY 9 2014/ DISCUSSION... AT 06Z...THERE WAS A WEAK AREA OF LOW PRESSURE OVER CENTRAL OKLAHOMA AND ANOTHER WEAK AREA OF LOW PRESSURE NORTH OF DEL RIO. SFC DEW PTS REMAIN IN THE LOWER 70S. RADAR IS A LITTLE MORE ACTIVE THAN THE PAST FEW NIGHTS WITH A LINE OF STORMS DEVELOPING ACROSS EXTREME SE TX FROM KBPT TO KGLS AND A SMALL CLUSTER NEAR KGRK. WATER VAPOR IMAGERY SHOWS A WELL DEFINED S/WV IN EASTERN NEW MEXICO AND THIS FEATURE WAS MOVING EAST AND WILL SERVE AS A CATALYST FOR SHRA/TSRA OVER PARTS OF CENTRAL AND EASTERN TEXAS TODAY. THE DISTURBANCE WILL APPROACH SE TX THIS AFTN AND FEEL IT WILL TRIGGER TSRA OVER MAINLY THE WESTERN HALF OF THE CWA. NAM 12 SOUNDING FOR KCLL ARE VERY UNSTABLE WITH PWATS INCREASING FROM 1.38 THIS MORNING TO 1.79 THIS AFTN. CAPE VALUES EXCEED 3000 J/KG AND LI`S DROP TO -9. SPC HAS OUTLOOKED THE WESTERN HALF OF SE TX IN SLIGHT RISK AND SEE NO REASON TO DISAGREE. THE NAM...GFS AND ECMWF ALL SHOW A SPEED MAX APPROACHING THIS AFTERNOON SO IT LOOKS LIKE ALL THE INGREDIENTS ARE IN PLACE FOR SOME SEVERE WEATHER OVER THE WESTERN ZONES. TOWARD THE HOUSTON AREA AND THE COAST...CAPPING LOOKS TO REMAIN AN ISSUE AND PWATS ACTUALLY DROP THIS AFTN. WILL MAINTAIN LOW END CHANCE POPS BUT SOUNDINGS LOOK MUCH LESS FAVORABLE. THINGS SHOULD SETTLE DOWN QUICKLY TONIGHT WITH THE LOSS OF HEATING. FWIW...THE HRRR INITIALIZED BEST THIS MORNING AND HAVE LEANED TOWARD THIS SOLUTION FOR THE SHORT TERM. VERY WARM AND HUMID CONDITIONS ARE EXPECTED OVER THE WEEKEND. CAN`T RULE OUT ISOLATED SHOWERS WITH HEATING EACH DAY. PWATS REMAIN AROUND 1.5-1.6 INCHES SO WILL MENTION A SLIGHT CHANCE OF SHRAS EACH DAY. THINGS BECOME A LITTLE MORE MUDDLED MON-WED. A DEEP UPPER LEVEL TROUGH AND SURFACE COLD FRONT WILL APPROACH THE STATE ON MONDAY. MODELS ARE IN GOOD AGREEMENT THROUGH MONDAY 12Z BUT DIVERGE SIGNIFICANTLY THEREAFTER. GFS IS ABOUT 24-30 HOURS FASTER THAN THE ECMWF. THE CANADIAN SUPPORTS THE SLOWER ECMWF. NOT REALLY SURE HOW THINGS WILL EVENTUALLY TRANSPIRE THIS FAR OUT SO HAVE STARTED POPS ON MONDAY AND WILL CARRY POPS THROUGH WEDNESDAY. AT THE CURRENT TIME...FEEL TUESDAY WILL BE THE BEST DAY FOR RAIN CHANCES BUT THAT IS SUBJECT TO CHANGE. HAVE RAISED RAIN CHANCES ON TUESDAY TO 50 PERCENT. CONSIDERABLY COOLER AND DRIER CONDITIONS WILL DEVELOP IN THE WAKE OF THE FRONT FOR THE SECOND HALF OF NEXT WEEK WITH MIN TEMPS POSSIBLY FALLING BACK INTO THE 50S. 43 MARINE... ONSHORE WINDS ARE EXPECTED THROUGH THE WEEKEND. WIND SPEEDS WILL BE HIGH ENOUGH THIS MORNING FOR CAUTION CONDITIONS. MODERATE TO STRONG ONSHORE WINDS ARE THEN EXPECTED TO DEVELOP SUNDAY NIGHT AS LOW PRESSURE DEVELOPS OVER THE PLAINS. THE MODELS THEN DIFFERED ON THE PASSAGE OF A COLD FRONT THROUGH SE TX AND OFF THE COAST. LIKED THE SLOWER ECMWF. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 86 69 88 71 88 / 30 30 10 10 10 HOUSTON (IAH) 86 71 87 73 87 / 40 20 20 10 20 GALVESTON (GLS) 81 73 82 73 82 / 40 20 20 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...46
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
638 AM CDT FRI MAY 9 2014 .DISCUSSION... SEE THE 12Z AVIATION DISCUSSION BELOW. 40 && .AVIATION... IFR TO MVFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE MORNING. THE MODELS ARE INDICATING POSSIBLE VFR DURING THE MID OR LATE AFTERNOON PERIOD. BEST CHANCES FOR SHOWERS OR THUNDERSTORMS WILL BE AT KCLL AND KUTS. HOWEVER...GIVEN THE MOISTURE CHANNEL OVER THE GULF...THERE IS A SLIGHT CHANCE OF SHOWERS FROM KHOU TO THE COAST THROUGH 15Z. MAY AMEND IF MORE SHOWERS THAN EXPECTED DEVELOP. THIS EVENING...MODEL SOUNDINGS INDICATE MVFR TO IFR CONDTIONS WILL DEVELOP. 40 && .PREV DISCUSSION... /ISSUED 333 AM CDT FRI MAY 9 2014/ DISCUSSION... AT 06Z...THERE WAS A WEAK AREA OF LOW PRESSURE OVER CENTRAL OKLAHOMA AND ANOTHER WEAK AREA OF LOW PRESSURE NORTH OF DEL RIO. SFC DEW PTS REMAIN IN THE LOWER 70S. RADAR IS A LITTLE MORE ACTIVE THAN THE PAST FEW NIGHTS WITH A LINE OF STORMS DEVELOPING ACROSS EXTREME SE TX FROM KBPT TO KGLS AND A SMALL CLUSTER NEAR KGRK. WATER VAPOR IMAGERY SHOWS A WELL DEFINED S/WV IN EASTERN NEW MEXICO AND THIS FEATURE WAS MOVING EAST AND WILL SERVE AS A CATALYST FOR SHRA/TSRA OVER PARTS OF CENTRAL AND EASTERN TEXAS TODAY. THE DISTURBANCE WILL APPROACH SE TX THIS AFTN AND FEEL IT WILL TRIGGER TSRA OVER MAINLY THE WESTERN HALF OF THE CWA. NAM 12 SOUNDING FOR KCLL ARE VERY UNSTABLE WITH PWATS INCREASING FROM 1.38 THIS MORNING TO 1.79 THIS AFTN. CAPE VALUES EXCEED 3000 J/KG AND LI`S DROP TO -9. SPC HAS OUTLOOKED THE WESTERN HALF OF SE TX IN SLIGHT RISK AND SEE NO REASON TO DISAGREE. THE NAM...GFS AND ECMWF ALL SHOW A SPEED MAX APPROACHING THIS AFTERNOON SO IT LOOKS LIKE ALL THE INGREDIENTS ARE IN PLACE FOR SOME SEVERE WEATHER OVER THE WESTERN ZONES. TOWARD THE HOUSTON AREA AND THE COAST...CAPPING LOOKS TO REMAIN AN ISSUE AND PWATS ACTUALLY DROP THIS AFTN. WILL MAINTAIN LOW END CHANCE POPS BUT SOUNDINGS LOOK MUCH LESS FAVORABLE. THINGS SHOULD SETTLE DOWN QUICKLY TONIGHT WITH THE LOSS OF HEATING. FWIW...THE HRRR INITIALIZED BEST THIS MORNING AND HAVE LEANED TOWARD THIS SOLUTION FOR THE SHORT TERM. VERY WARM AND HUMID CONDITIONS ARE EXPECTED OVER THE WEEKEND. CAN`T RULE OUT ISOLATED SHOWERS WITH HEATING EACH DAY. PWATS REMAIN AROUND 1.5-1.6 INCHES SO WILL MENTION A SLIGHT CHANCE OF SHRAS EACH DAY. THINGS BECOME A LITTLE MORE MUDDLED MON-WED. A DEEP UPPER LEVEL TROUGH AND SURFACE COLD FRONT WILL APPROACH THE STATE ON MONDAY. MODELS ARE IN GOOD AGREEMENT THROUGH MONDAY 12Z BUT DIVERGE SIGNIFICANTLY THEREAFTER. GFS IS ABOUT 24-30 HOURS FASTER THAN THE ECMWF. THE CANADIAN SUPPORTS THE SLOWER ECMWF. NOT REALLY SURE HOW THINGS WILL EVENTUALLY TRANSPIRE THIS FAR OUT SO HAVE STARTED POPS ON MONDAY AND WILL CARRY POPS THROUGH WEDNESDAY. AT THE CURRENT TIME...FEEL TUESDAY WILL BE THE BEST DAY FOR RAIN CHANCES BUT THAT IS SUBJECT TO CHANGE. HAVE RAISED RAIN CHANCES ON TUESDAY TO 50 PERCENT. CONSIDERABLY COOLER AND DRIER CONDITIONS WILL DEVELOP IN THE WAKE OF THE FRONT FOR THE SECOND HALF OF NEXT WEEK WITH MIN TEMPS POSSIBLY FALLING BACK INTO THE 50S. 43 MARINE... ONSHORE WINDS ARE EXPECTED THROUGH THE WEEKEND. WIND SPEEDS WILL BE HIGH ENOUGH THIS MORNING FOR CAUTION CONDITIONS. MODERATE TO STRONG ONSHORE WINDS ARE THEN EXPECTED TO DEVELOP SUNDAY NIGHT AS LOW PRESSURE DEVELOPS OVER THE PLAINS. THE MODELS THEN DIFFERED ON THE PASSAGE OF A COLD FRONT THROUGH SE TX AND OFF THE COAST. LIKED THE SLOWER ECMWF. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 86 69 88 71 88 / 50 30 10 10 10 HOUSTON (IAH) 86 71 87 73 87 / 30 20 20 10 20 GALVESTON (GLS) 81 73 82 73 82 / 30 20 20 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43 AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS TAUNTON MA
509 PM EDT FRI MAY 9 2014 .SYNOPSIS... A WARM FRONT WILL APPROACH TONIGHT BRINGING A PERIOD OF SCATTERED SHOWERS BEFORE IT LIFTS INTO NORTHERN NEW ENGLAND SATURDAY. BEHIND THE FRONT A WARMER AND MORE HUMID AIRMASS OVERSPREADS THE REGION SATURDAY. A COLD FRONT WILL MOVE ACROSS THE AREA LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING...YIELDING A ROUND OF SCATTERED SHOWERS. HIGH PRESSURE BUILDS IN FOR MOTHERS DAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 345 PM UPDATE... WARM FRONT ACROSS WESTERN PA AND NY WILL APPROACH THE REGION LATER TONIGHT. BEFORE THEN COOL PREFRONTAL AIRMASS REMAINS OVER SOUTHERN NEW ENGLAND AS ONSHORE FLOW MAINTAINS COOL MOIST SHALLOW AIRMASS. WATER VAPOR IMAGERY ALONG WITH MODEL CROSS SECTIONS AND TIME SECTIONS REVEAL MID LEVEL DRY AIR OVERSPREAD THE REGION AS WELL. THIS COMBINED WITH MOIST SHALLOW ONSHORE FLOW IS RESULTING IN AREAS OF DRIZZLE AND FOG ESPECIALLY IN THE CT RVR VLY AND THE HIGHER TERRAIN /UPSLOPE FLOW/. THIS WILL BECOME MORE WIDESPREAD THIS EVENING ESPECIALLY WITH SUNSET. THUS NO APPRECIABLE RAINFALL THIS EVENING. NOT A WASHOUT JUST SPOTTY LIGHT RAIN/DRIZZLE. LAST SEVERAL RUNS OF THE HRRR SUPPORT THIS THINKING AS WELL. LATER TONIGHT WARM FRONT ENTERS THE REGION WITH RAIN BECOMING MORE WIDESPREAD AS MODELS INDICATE MODEST ISENTROPIC LIFT/UPGLIDE ACROSS THE REGION 06-12Z. MARGINAL INSTABILITY ALOFT TO SUPPORT A VERY LOW RISK OF AN ISOLATED TSTM WITH LOCALLY BRIEF HEAVY DOWNPOUR TOWARD SUNRISE. HOWEVER MUCH OF THE ACTIVITY SHOULD BE ON THE LIGHT SIDE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... SATURDAY...WARM FRONT LIFTS NORTH OF THE REGION BY MID TO LATE MORNING WITH WARM SECTOR OVERSPREADING SOUTHERN NEW ENGLAND. DEFINITELY A BIT OF A SUMMER-ISH FEEL TO THE AIRMASS TOMORROW WITH MAY SUNSHINE LIFTING TEMPS INTO THE 70S AND DEW PTS IN THE L60S. AS FOR INSTABILITY DETERMINISTIC AND ENSEMBLE GUIDANCE SUGGEST ONLY 200-500 J/KG OF MU AND MEAN CAPE TOMORROW AFTERNOON. NOT MUCH OF A TRIGGER TOMORROW AFTERNOON AS MID LEVEL TROUGH REMAINS WELL TO THE WEST ALONG WITH ATTENDING COLD FRONT. THUS THINKING AREAL COVERAGE OF ANY SHOWERS WILL BE ISOLATED TO WIDELY SCATTERED. GIVEN MU CAPES ARE ONLY 500J/KG OR LESS ALONG WITH MARGINAL WIND FIELDS ALOFT...ANY TSTMS SHOULD BE ISOLATED AND NON SEVERE. GIVEN THE HIGHER PWAT AIRMASS CAN`T RULE OUT A BRIEF HEAVY DOWNPOUR. OTHERWISE A TYPICAL LATE WARM SPRING AFTERNOON WITH ISOLATED- WIDELY SCATTERED SHOWERS. ANY MORNING FOG WILL BURN OFF BY MIDDAY. SATURDAY NIGHT...SHOWERS MAY BECOME MORE WIDESPREAD AS COLD FRONT APPROACHES ALONG WITH POSSIBLE SURFACE WAVE ON THE FRONT. THIS WOULD RESULT IN SHOWERS MOST NUMEROUS ALONG THE SOUTH COAST. LOW RISK OF AN ISOLATED TSTM WITH HEAVY RAINFALL. IMPROVING CONDITIONS TOWARD 12Z SUN FROM WEST TO EAST. GIVEN POST FRONTAL AIRMASS DOESNT ARRIVE UNTIL SUNDAY IT WILL BE A MILD NIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * DRY...WARM WEATHER FOR MOTHERS DAY AND MONDAY * BACKDOOR COLD FRONT MOVES INLAND MONDAY NIGHT INTO TUESDAY WITH SCATTERED SHOWERS * NEAR TO BELOW NORMAL TEMPS WITH SPOTTY SHOWERS WEDNESDAY THROUGH FRIDAY MODEL CONFIDENCE AND PREFERENCES... NOTING THAT THE 06Z AND 12Z GFS OP RUNS ALONG WITH 12Z GGEM HAVE COME ON BOARD WITH THE LAST SEVERAL RUNS OF THE ECMWF WITH MAJOR CHANGES IN THE UPPER LEVEL LONG WAVE PATTERN EARLY NEXT WEEK. NOW EXPECTING A BUILDING RIDGE ACROSS THE EASTERN U.S. WITH DEEPENING TROUGH OVER THE CENTRAL U.S. EARLY NEXT WEEK. AS THE RIDGE BUILDS ALOFT...SURFACE RIDGING ALSO BUILDS ACROSS QUEBEC AND LABRADOR THEN SHIFTS DOWN THE ATLC COAST...CAUSING A BACKDOOR COLD FRONT TO CROSS THE REGION FROM NE TO SW AROUND THE LATE MON NIGHT OR TUE TIMEFRAME. THE FRONT WILL TEND TO STALL MAINLY ACROSS EASTERN/CENTRAL NY STATE INTO N NJ. SO...WILL LIKELY SEE NEAR OR BELOW NORMAL TEMPS IN THE MID TO LATTER PORTIONS OF NEXT WEEK WITH MARITIME AIR OFF THE COLD OCEAN /SEA SURFACE TEMPS IN THE UPPER 40S/. TIMING OF MIGRATION OF THE UPPER TROUGH EASTWARD OUT OF THE GREAT LAKES AND OHIO VALLEY LATE NEXT WEEK LENDS TO LOWER CONFIDENCE WITH THE APPROACH OF SURFACE COLD FRONT AS IT BUMPS INTO THE HIGH AMPLITUDE SURFACE AND UPPER RIDGES. USED A BLEND OF MOST MODEL GUIDANCE FOR THIS PACKAGE...INCLUDING WPC GUIDANCE WHICH ALSO INCORPORATED ENSEMBLE MEANS. DETAILS... SUNDAY... WILL SEE A DRY AND MILD SPRING DAY FOR MOTHERS DAY AS WEAK HIGH PRES RIDGE CROSSES THE REGION. WILL BE A BREEZY DAY WITH W WINDS GUSTING UP TO 20-25 MPH...HIGHEST WELL INLAND. EXPECT HIGHS MAINLY IN THE 70S...EXCEPT A BIT COOLER ALONG THE IMMEDIATE COAST. CLOUDS WILL START TO INCREASE ACROSS N CT/W MA AFTER MIDNIGHT. MONDAY... ISENTROPIC LIFT MOVES IN ACROSS THE REGION AS WARM FRONT BEGINS TO APPROACH. HOWEVER...AS RIDGING BUILDS TO THE W...THIS FRONT HANGS UP ACROSS THE REGION. EXPECT SOME SCT SHOWERS TO MOVE ACROSS MON AFTERNOON/NIGHT. ALSO NOTING SOME ELEVATED CONVECTION POSSIBLE ALONG WITH LIFTED INDICES DROPPING AT OR BELOW ZERO AS THE DAY PROGRESSES. HAVE ALSO MENTIONED ISOLD THUNDER. COULD BE A RATHER MILD DAY WITH SOME READINGS POSSIBLY CLOSE TO 80 WELL INLAND...BUT UNCERTAIN OF THIS DUE TO STALLING FRONT ACROSS THE REGION. CURRENT MODELS SUGGEST THAT HIGH PRES WILL BEGIN TO SURGE DOWN FROM MAINE LATE MON NIGHT...SO STALLED FRONT COULD BEGIN TO SHIFT S-SW. SOMETHING TO MONITOR. TUESDAY... MODELS HAVE COME IN LINE IN PUSHING BACKDOOR FRONT ACROSS THE REGION...FROM NE-SW DURING THE DAY. WILL STILL SEE SOME SCT SHOWERS BUT SHOULD PUSH FROM E TO W DURING THE AFTERNOON. MAY STILL SEE SOME ISOLD THUNDER ACROSS N CT/RI THROUGH ABOUT MIDDAY...THEN WILL PUSH OFF THE S COAST. E-NE WINDS WILL BE GUSTY ALONG THE E COAST...POSSIBLY UP TO AROUND 25 MPH DURING TUE AFTERNOON/EVENING. TEMPS WILL RANGE FROM THE UPPER 50S TO MID 60S ALONG THE E COAST TO THE LOWER-MID 70S ACROSS THE CT VALLEY. WILL BE CHILLY TUE NIGHT WITH LOWS MAINLY IN THE MID-UPPER 40S WITH SOME LOWER 50S IN THE LOWER CT VALLEY. WEDNESDAY THROUGH FRIDAY... LARGE H5 RIDGING BUILDS ACROSS THE EASTERN U.S. WHILE TROUGH DIGS ACROSS CENTRAL AREAS. THIS WILL SLOW SURFACE SYSTEMS DOWN AS FRONT STALLS ACROSS EASTERN NY STATE INTO N NJ. EXPECT SLIGHT CHANCE TO LOW CHANCE POPS TO LINGER ACROSS CT VALLEY AND E SLOPES OF THE BERKSHIRES INTO WED NIGHT...THEN MAY START TO SHIFT E AS UPPER TROUGH/SURFACE COLD FRONT MAY START TO APPROACH THOUGH TIMING IS IN QUESTION. EXPECT HIGHS EACH DAY TO RUN CLOSE TO OR UP TO 5 DEGS BELOW SEASONAL NORMS. MODELS DO DIVERGE ON HOW IT RESOLVES THEIR TIMING OF THE UPPER TROUGH INTO THE EASTERN U.S...POSSIBLY NOT UNTIL NEXT WEEKEND. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...LOW CONFIDENCE. THRU 00Z...LOW CONFIDENCE FORECAST AS TIMING OF IFR CONDITIONS IMPROVING TO MVFR STILL SOMEWHAT UNCERTAIN. WHERE IFR EXISTS NOW THINK WE WILL SEE SOME BRIEF IMPROVEMENT TO MVFR AFTER 21Z AS WINDS SHIFT FROM NE TO SE. ELSEWHERE MVFR SHOULD PREVAIL. AS FOR THE CT RVR VLY MARGINAL IFR/MVFR WILL CONTINUE. PATCHY FOG AND DRIZZLE POSSIBLE ALL TERMINALS. ALTHOUGH HEAVY RAIN/THUNDER NOT EXPECTED. AFTER 00Z...MVFR WILL TREND TO IFR AS THE NIGHT PROGRESSES. PATCHY FOG AND DRIZZLE POSSIBLE ALL TERMINALS. BETTER CHANCE OF WIDESPREAD RAIN TOWARD MORNING. VERY LOW RISK OF ISOLATED THUNDER TOWARD 12Z. SATURDAY...ANY LEFTOVER IFR IN THE MORNING WILL LIFT TO MVFR OR EVEN VFR TOWARD MIDDAY AND ESPECIALLY DURING THE AFTERNOON. ISOLATED-SCATTERED SHOWERS EARLY ACROSS EASTERN MA AND RI. THEN ANOTHER ROUND OF ISOLATED-SCATTERED SHOWERS DURING THE AFTERNOON WITH A VERY LOW RISK OF AN ISOLATED TSTM. SAT NIGHT...SHOWERS SHOULD BECOME MORE NUMEROUS ESPECIALLY ALONG THE SOUTH COAST. SOME HEAVY RAIN POSSIBLE. AS FOR CIGS/VSBYS ANY EARLY VFR CONDITIONS QUICKLY LOWER TO MVFR AND EVENTUALLY IFR OVERNIGHT FROM WEST TO EAST. KBOS TERMINAL...LOW CONFIDENCE. IFR SHOULD LIMIT BRIEFLY TO MVFR AFTER 21Z AS WINDS SHIFT FROM NE TO SE AND THEN S. MVFR LOWERS TO IFR LATER TONIGHT AS SHOWERS BECOME MORE NUMEROUS TOWARD 12Z SAT. THEN CONDITIONS IMPROVE TO MVFR AND EVENTUALLY VFR SAT AFTERNOON. ISOLATED-SCATTERED AFTERNOON SHOWERS. KBDL TERMINAL...LOW CONFIDENCE. IFR CONDITIONS IN THE CT RVR VLY SHOULD LIFT TO MVFR BRIEFLY THIS EVENING BEFORE LOWERING AGAIN LATER TONIGHT AS SHOWERS BECOME MORE NUMEROUS. OUTLOOK...SUNDAY THROUGH WEDNESDAY... SUNDAY...HIGH CONFIDENCE. VFR CONDITIONS. W WIND GUSTS UP TO 20-25 KT POSSIBLE. PATCHY FOG POSSIBLE ALONG IMMEDIATE S COAST LATE SUN NIGHT WITH LOCAL MVFR-IFR VSBYS. MONDAY...MODERATE CONFIDENCE. VFR CONDITIONS TO START. MAY SEE SCT SHOWERS/ISOLD TSTMS DURING MONDAY AFTERNOON/NIGHT WITH LOCAL MVFR-IFR CIGS/VSBYS. PATCHY FOG LATE MON NIGHT WITH MVFR-IFR VSBYS MAINLY ALONG S COAST. TUESDAY...LOW TO MODERATE CONFIDENCE...MAINLY FOR TIMING. BACK DOOR COLD FRONT WILL SHIFT FROM NE TO SW DURING TUE. WINDS SHIFT FROM LIGHT W TO E-NE FROM E MA WESTWARD. GUSTS UP TO 20-25 KT MAINLY ALONG E COAST. WILL SEE VFR CONDITIONS...BUT MAY SEE LOWER CLOUDS WITH POCKETS OF FOG AND DRIZZLE ACROSS E MA DURING TUE AFTERNOON/NIGHT. MVFR-IFR CONDITIONS POSSIBLE. LEFTOVER SCT SHOWERS/ISOLD THUNDER INTO TUE EVENING...THEN SHIFTS W. WEDNESDAY...LOW TO MODERATE CONFIDENCE. WIDELY SCT SHOWERS LINGER ACROSS CT VALLEY TO E SLOPES OF BERKSHIRES WED...WHILE POCKETS OF MVFR-IFR CIGS/VSBYS POSSIBLY LINGER ACROSS E COASTAL AREAS WITH ONSHORE WINDS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...MODERATE CONFIDENCE. TONIGHT...NE/SE WINDS BECOME SSW LATER TONIGHT. PATCHY FOG AND DRIZZLE MAY LOWER VSBY 1-3 MILES WITH A LOW RISK OF DENSE FOG SOUTH COASTAL WATERS. SHOWERS BECOME MORE WIDESPREAD TOWARD DAYBREAK. SATURDAY...WARM FRONT LIFTS NORTH OF THE REGION WITH WINDS BECOMING SSW 15-20 KT WITH A FEW GUSTS APPROACHING 25 KT NEAR SHORE. NO SMALL CRAFT ADVISORY AT THE MOMENT AS DURATION AND FREQUENCY OF 25 KT REMAINS SOMEWHAT UNCERTAIN. ISOLATED-WIDELY SCATTERED SHOWERS. VERY LOW RISK OF ISOLATED TSTM NEAR SHORE. ANY MORNING FOG SHOULD BURN OFF BY EARLY AFTERNOON. SAT NIGHT...COLD FRONT APPROACHES FROM THE WEST WITH SHOWERS BECOMING MORE WIDESPREAD. VSBY SHOULD BE GOOD GIVEN SW WINDS. OUTLOOK...SUNDAY THROUGH WEDNESDAY... MODERATE CONFIDENCE THROUGH PERIOD. SUNDAY... HIGH PRES RIDGE BUILDS ACROSS THE WATERS. EXPECT W WINDS 15 KT OR LESS INTO SUN NIGHT. MAY SEE W GUSTS CLOSE TO 25 KT ON NEARSHORE WATERS DURING THE AFTERNOON. SEAS SHOULD REMAIN BELOW 5 FT. VSBY RESTRICTIONS LATE SUN NIGHT POSSIBLE ALONG IMMEDIATE S COASTAL WATERS. MONDAY... FRONT APPROACHES THE WATERS BUT STALLS. S-SW WINDS REMAIN AT 15 KT OR LESS...THEN DIMINISH INTO MON NIGHT AS BACKDOOR FRONT APPROACHES. NOTING WIND SHIFT TO N OVER THE EASTERN OUTER WATERS AFTER MIDNIGHT. COULD SEE SCT SHOWERS/ISOLD THUNDER MON AFTERNOON/NIGHT WITH FRONT IN VICINITY. TUESDAY-WEDNESDAY... BACKDOOR FRONT MOVES SW ACROSS THE WATERS TUE. WINDS SHIFT TO NE...GUSTING UP TO AROUND 20 KT ON THE OPEN WATERS BEGINNING TUE AFTERNOON THROUGH WED. EXPECT E-NE SWELLS TO BUILD TO AROUND 5 FT ON THE OUTER WATERS. SCT SHOWERS/ISOLD THUNDER STILL POSSIBLE INTO TUE EVENING BUT WILL SHIFT SW AS FRONT PASSES TUE NIGHT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/EVT NEAR TERM...NOCERA SHORT TERM...EVT LONG TERM...EVT AVIATION...NOCERA/EVT MARINE...NOCERA/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
348 PM EDT FRI MAY 9 2014 .SYNOPSIS... A WARM FRONT WILL APPROACH TONIGHT BRINGING A PERIOD OF SCATTERED SHOWERS BEFORE IT LIFTS INTO NORTHERN NEW ENGLAND SATURDAY. BEHIND THE FRONT A WARMER AND MORE HUMID AIRMASS OVERSPREADS THE REGION SATURDAY. A COLD FRONT WILL MOVE ACROSS THE AREA LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING...YIELDING A ROUND OF SCATTERED SHOWERS. HIGH PRESSURE BUILDS IN FOR MOTHERS DAY. MILD TEMPERATURES AND UNSETTLED WEATHER ARE ANTICIPATED FOR MOST OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 345 PM UPDATE... WARM FRONT ACROSS WESTERN PA AND NY WILL APPROACH THE REGION LATER TONIGHT. BEFORE THEN COOL PREFRONTAL AIRMASS REMAINS OVER SOUTHERN NEW ENGLAND AS ONSHORE FLOW MAINTAINS COOL MOIST SHALLOW AIRMASS. WATER VAPOR IMAGERY ALONG WITH MODEL CROSS SECTIONS AND TIME SECTIONS REVEAL MID LEVEL DRY AIR OVERSPREAD THE REGION AS WELL. THIS COMBINED WITH MOIST SHALLOW ONSHORE FLOW IS RESULTING IN AREAS OF DRIZZLE AND FOG ESPECIALLY IN THE CT RVR VLY AND THE HIGHER TERRAIN /UPSLOPE FLOW/. THIS WILL BECOME MORE WIDESPREAD THIS EVENING ESPECIALLY WITH SUNSET. THUS NO APPRECIABLE RAINFALL THIS EVENING. NOT A WASHOUT JUST SPOTTY LIGHT RAIN/DRIZZLE. LAST SEVERAL RUNS OF THE HRRR SUPPORT THIS THINKING AS WELL. LATER TONIGHT WARM FRONT ENTERS THE REGION WITH RAIN BECOMING MORE WIDESPREAD AS MODELS INDICATE MODEST ISENTROPIC LIFT/UPGLIDE ACROSS THE REGION 06-12Z. MARINGAL INSTABILITY ALOFT TO SUPPORT A VERY LOW RISK OF AN ISOLATED TSTM WITH LOCALLY BRIEF HEAVY DOWNPOUR TOWARD SUNRISE. HOWEVER MUCH OF THE ACTIVITY SHOULD BE ON THE LIGHT SIDE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... SATURDAY...WARM FRONT LIFTS NORTH OF THE REGION BY MID TO LATE MORNING WITH WARM SECTOR OVERSPREADING SOUTHERN NEW ENGLAND. DEFINITELY A BIT OF A SUMMER-ISH FEEL TO THE AIRMASS TOMORROW WITH MAY SUNSHINE LIFTING TEMPS INTO THE 70S AND DEW PTS IN THE L60S. AS FOR INSTABILITY DETERMINISTIC AND ENSEMBLE GUIDANCE SUGGEST ONLY 200-500 J/KG OF MU AND MEAN CAPE TOMORROW AFTERNOON. NOT MUCH OF A TRIGGER TOMORROW AFTERNOON AS MID LEVEL TROUGH REMAINS WELL TO THE WEST ALONG WITH ATTENDING COLD FRONT. THUS THINKING AREAL COVERAGE OF ANY SHOWERS WILL BE ISOLATED TO WIDELY SCATTERED. GIVEN MU CAPES ARE ONLY 500J/KG OR LESS ALONG WITH MARGINAL WIND FIELDS ALOFT...ANY TSTMS SHOULD BE ISOLATED AND NON SEVERE. GIVEN THE HIGHER PWAT AIRMASS CAN`T RULE OUT A BRIEF HEAVY DOWNPOUR. OTHERWISE A TYPICAL LATE WARM SPRING AFTERNOON WITH ISOLATED- WIDELY SCATTERED SHOWERS. ANY MORNING FOG WILL BURN OFF BY MIDDAY. SATURDAY NIGHT...SHOWERS MAY BECOME MORE WIDESPREAD AS COLD FRONT APPROACHES ALONG WITH POSSIBLE SURFACE WAVE ON THE FRONT. THIS WOULD RESULT IN SHOWERS MOST NUMEROUS ALONG THE SOUTH COAST. LOW RISK OF AN ISOLATED TSTM WITH HEAVY RAINFALL. IMPROVING CONDITIONS TOWARD 12Z SUN FROM WEST TO EAST. GIVEN POST FRONTAL AIRMASS DOESNT ARRIVE UNTIL SUNDAY IT WILL BE A MILD NIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * DRY...WARM WEATHER FOR MOTHERS DAY * AVERAGE TEMPERATURES AND UNSETTLED WEATHER FOR THE WORK WEEK MODELS AND CONFIDENCE... 00Z GUIDANCE AGREES THAT A ROCKIES/PLAINS TROUGH WILL BROADEN AS IT MOVES EWD WITH TIME... YIELDING A MEAN TROUGH COVERING MUCH OF THE ERN HALF OF THE CONUS/CANADA BY LATE NEXT WEEK. HOWEVER SIGNIFICANT DIFFERENCES EXIST FOR SOME DETAILS WITHIN THIS EVOLUTION...CAUSING A LOW CONFIDENCE FORECAST. THE MOST PRONOUNCED IS A FASTER ADVANCE OF THE INITIAL TROUGH IN RECENT GFS/GEFS RUNS WITH TRENDS AND OTHER MODELS GENERALLY SUPPORTING SLOWER TIMING. THEREFORE TRENDED TOWARDS PREVIOUS FORECAST AND WPC. OVERALL HAVE A MEDIUM CONFIDENCE THAT POP-UP SHOWERS AND ISO THUNDERSTORMS WILL OCCUR ON MONDAY...BUT A LOW CONFIDENCE BEYOND THAT. DETAILS... SUNDAY... COLD FRONT WILL CROSS THE REGION OVERNIGHT SATURDAY INTO SUNDAY MORNING. A FEW SCT SHOWERS AND MAYBE AN ISO TSTORM ARE POSSIBLE ALONG THE FRONT. COLD FRONT SHOULD BE OFFSHORE BY 12Z SUNDAY ALLOWING FOR SURFACE HIGH PRESSURE TO BUILD IN TO THE AREA FOR MOTHERS DAY. SUBSIDENCE WILL FILTER IN WITH THE HIGH PRESSURE ALLOWING FOR DRY WEATHER. FORECAST SOUNDINGS SUGGEST MIXING CLOSE TO 850MB TEMPS WHICH WILL YIELD TO GUSTS NEAR 20-25 MPH. TEMPS COULD REACH THE UPPER 70S TO LOW 80S AWAY FROM THE COASTS AS 850 MB TEMPS STAY ABOUT 8C BEHIND THE FRONT. SUNDAY IS THE PICK OF THE WEEK. MONDAY AND TUESDAY... WARM...MOIST AIRMASS IN PLACE ACROSS THE REGION FOR MONDAY AND TUESDAY. GUIDANCE IS SHOWING A WARM FRONT TRYING TO APPROACH THE REGION WHICH COULD SPARK SOME SCATTERED SHOWERS AND ISO THUNDERSTORMS DURING DIURNAL HEATING...ESP ON MONDAY. SURFACE CAPE VALUES WILL REACH NEAR 1000 J/KG AND WITH SHOWALTERS DROPPING BELOW 0 HAVE INSERTED THE MENTION FOR THUNDER. THE EC AND GFS BEGIN TO DIVERGE AT THIS POINT AS THE EC DROPS A BACK DOOR COLD FRONT ACROSS NEW ENGLAND ON TUESDAY. THE GFS ALSO HINTS AT THIS BUT IS NOT AS STRONG AS THE EC. BETWEEN THESE 2 FORECAST GUIDANCE...THERE IS A 20F SURFACE HIGH TEMP DIFFERENCE FOR TUESDAY. THE CANADIAN AND A FEW MEMBERS OF THE GEFS ALSO DISPLAYS THIS BACK DOOR FRONT PUSHING ALL THE WAY THROUGH THE AREA...AS WELL AS WPC. BECAUSE OF THIS TREND HAVE BEGUN CUTTING TEMPS FOR TUESDAY AND DISPLAYING THE POSSIBILITY OF THE BACK DOOR FRONT. ALTHOUGH IT MAY BE COOLER THEN FORECASTED...RIGHT NOW JUST SETTLING ON A TREND. WEDNESDAY AND BEYOND... BY WEDNESDAY...A DEEP UPPER TROUGH THAT HAS DUG ACROSS THE CENTRAL CONUS HAS MOVED EASTWARD OVER THE MIDWEST. THIS TROUGH WILL CONTINUE TO SLOWLY TRACK EASTWARD DURING THE REST OF THE WEEK. EXPECT SEVERAL WEAK WAVES TO DEVELOP AHEAD OF THIS TROUGH AND WILL APPROACH THE AREA DURING THIS TIMEFRAME. AS A RESULT...HAVE CONTINUED TO MENTION THE POSSIBILITY OF A CHANCE OF POPS FOR SHOWERS/TSTMS FROM WEDNESDAY THROUGH FRIDAY. MODEL GUIDANCE INDICATES THE TROUGH WILL SLIDE OFFSHORE BY EITHER FRIDAY OR SATURDAY. A MILD AIR MASS OVERSPREADS THE REGION WITH SW FLOW AHEAD OF THE TROUGH. HIGHS WILL GENERALLY TOP OFF IN THE UPPER 60S TO LOW 70S WITH COOLER CONDITIONS ALONG THE COAST...ESP THE SOUTH COAST DUE TO SOUTHERLY FLOW. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...LOW CONFIDENCE. THRU 00Z...LOW CONFIDENCE FORECAST AS TIMING OF IFR CONDITIONS IMPROVING TO MVFR STILL SOMEWHAT UNCERTAIN. WHERE IFR EXISTS NOW THINK WE WILL SEE SOME BRIEF IMPROVEMENT TO MVFR AFTER 21Z AS WINDS SHIFT FROM NE TO SE. ELSEWHERE MVFR SHOULD PREVAIL. AS FOR THE CT RVR VLY MARGINAL IFR/MVFR WILL CONTINUE. PATCHY FOG AND DRIZZLE POSSIBLE ALL TERMINALS. ALTHOUGH HEAVY RAIN/THUNDER NOT EXPECTED. AFTER 00Z...MVFR WILL TREND TO IFR AS THE NIGHT PROGRESSES. PATCHY FOG AND DRIZZLE POSSIBLE ALL TERMINALS. BETTER CHANCE OF WIDESPREAD RAIN TOWARD MORNING. VERY LOW RISK OF ISOLATED THUNDER TOWARD 12Z. SATURDAY...ANY LEFTOVER IFR IN THE MORNING WILL LIFT TO MVFR OR EVEN VFR TOWARD MIDDAY AND ESPECIALLY DURING THE AFTERNOON. ISOLATED-SCATTERED SHOWERS EARLY ACROSS EASTERN MA AND RI. THEN ANOTHER ROUND OF ISOLATED-SCATTERED SHOWERS DURING THE AFTERNOON WITH A VERY LOW RISK OF AN ISOLATED TSTM. SAT NIGHT...SHOWERS SHOULD BECOME MORE NUMEROUS ESPECIALLY ALONG THE SOUTH COAST. SOME HEAVY RAIN POSSIBLE. AS FOR CIGS/VSBYS ANY EARLY VFR CONDITIONS QUICKLY LOWER TO MVFR AND EVENTUALLY IFR OVERNIGHT FROM WEST TO EAST. KBOS TERMINAL...LOW CONFIDENCE. IFR SHOULD LIMIT BRIEFLY TO MVFR AFTER 21Z AS WINDS SHIFT FROM NE TO SE AND THEN S. MVFR LOWERS TO IFR LATER TONIGHT AS SHOWERS BECOME MORE NUMEROUS TOWARD 12Z SAT. THEN CONDITIONS IMPROVE TO MVFR AND EVENTUALLY VFR SAT AFTERNOON. ISOLATED-SCATTERED AFTERNOON SHOWERS. KBDL TERMINAL...LOW CONFIDENCE. IFR CONDITIONS IN THE CT RVR VLY SHOULD LIFT TO MVFR BRIEFLY THIS EVENING BEFORE LOWERING AGAIN LATER TONIGHT AS SHOWERS BECOME MORE NUMEROUS. OUTLOOK...SUNDAY THROUGH TUESDAY... SUNDAY...MODERATE CONFIDENCE. COLD FRONTAL PASSAGE WILL ALLOW FOR SCT SHOWERS AND POSSIBLE MVFR CIGS AND VSBYS. THERE IS A LOW PROB OF A TSRA...WITH OVER THE CAPE AND ISLANDS HAVING THE BEST SHOT DURING THIS TIMEFRAME. OTHERWISE IMPROVING CONDITIONS FROM WEST TO EAST ON SUNDAY. GUSTY WINDS UP TO 25 KTS POSSIBLE. MONDAY-TUESDAY...MODERATE CONFIDENCE. VFR CONDITIONS TO START. MAY SEE POP-UP SHOWERS AND THUNDERSTORMS DURING THE DAY DROPPING VSBYS AND CIGS. POSSIBLE BACK DOOR COLD FRONT ON TUESDAY SWITCHING THE WESTERLY WINDS TO THE EAST ALLOWING FOR FOG AND DRIZZLE TO ROLL IN. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...MODERATE CONFIDENCE. TONIGHT...NE/SE WINDS BECOME SSW LATER TONIGHT. PATCHY FOG AND DRIZZLE MAY LOWER VSBY 1-3 MILES WITH A LOW RISK OF DENSE FOG SOUTH COASTAL WATERS. SHOWERS BECOME MORE WIDESPREAD TOWARD DAYBREAK. SATURDAY...WARM FRONT LIFTS NORTH OF THE REGION WITH WINDS BECOMING SSW 15-20 KT WITH A FEW GUSTS APPROACHING 25 KT NEAR SHORE. NO SMALL CRAFT ADVISORY AT THE MOMENT AS DURATION AND FREQUENCY OF 25 KT REMAINS SOMEWHAT UNCERTAIN. ISOLATED-WIDELY SCATTERED SHOWERS. VERY LOW RISK OF ISOLATED TSTM NEAR SHORE. ANY MORNING FOG SHOULD BURN OFF BY EARLY AFTERNOON. SAT NIGHT...COLD FRONT APPROACHES FROM THE WEST WITH SHOWERS BECOMING MORE WIDESPREAD. VSBY SHOULD BE GOOD GIVEN SW WINDS. OUTLOOK...SUNDAY THROUGH TUESDAY... MODERATE CONFIDENCE THROUGH PERIOD. SUNDAY...COLD FRONT WILL PUSH OVER THE WATERS BY SUNDAY MORNING ALLOW FOR SCT SHOWERS AND SOME ISO THUNDER. SEAS WILL REMAIN AT OR NEAR 5 FT. SCA MAY STILL BE NEEDED ESP ACROSS NEAR SHORE WATERS ON SUNDAY AS THE LAND MAY GUST UP TO 25KTS. MONDAY-TUESDAY... WARM FRONT WILL APPROACH FROM THE SOUTH ALLOWING FOR SCT SHOWERS AND ISO THUNDER. BEST CHANCES ARE IN THE BAY AND HARBORS. OTHERWISE WESTERLY WINDS WILL SHIFT TO THE EAST ON TUESDAY AS BACK DOOR COLD FRONT MOVES ACROSS THE WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA NEAR TERM...NOCERA SHORT TERM...NOCERA LONG TERM...DUNTEN AVIATION...NOCERA/DUNTEN MARINE...NOCERA/DUNTEN
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
250 PM EDT FRI MAY 9 2014 .SYNOPSIS... 18Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUES TO SHOW AN AMPLIFIED UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. LONGWAVE TROUGHING SITS OVER THE CENTRAL PLAINS WITH A POTENT SHORTWAVE IMPULSE PIVOTING NORTHWARD OVER THE UPPER MS VALLEY/WESTERN GREAT LAKES. THE DOWNSTREAM FLOW THEN RIDGES UP OVER THE EASTERN SEABOARD EXTENDING FROM THE EASTERN GULF/FLORIDA PENINSULA TO QUEBEC. WV IMAGERY SHOWS A BIT MORE UPPER LEVEL MOISTURE HAS WORKED OVERHEAD COMPARED TO PREVIOUS DAYS...AND THIS WILL COME IN THE FORM OF PERIODIC CIRRUS. THIS HIGH LEVEL MOISTURE IS SHOWN ON THE 12Z KTBW SOUNDING ABOVE 400MB...HOWEVER BELOW THIS LEVEL...THE SUPPRESSION FROM THE UPPER RIDGE CONTINUES TO SUPPLY US WITH A DRY COLUMN THROUGH A MAJORITY OF THE TROP. AT THE SURFACE...RIDGE OF HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC CONTINUES TO RIDGE BACK TO THE WEST WITH AN AXIS NEAR THE I-10 CORRIDOR. OUR POSITION TO THE SOUTH OF THIS RIDGE AXIS IS PROVIDING A LIGHT SOUTHEAST SYNOPTIC FLOW TO THE REGION. HOWEVER...AT THE COAST WINDS HAVE SHIFTED ONSHORE WITH THE DEVELOPMENT OF THE AFTERNOON SEA-BREEZE. TEMPERATURES ARE IN THE UPPER 80S TO LOWER 90S ACROSS THE INTERIOR AND IN THE LOWER TO MIDDLE 80S AT THE BEACHES. EARLY SHALLOW CU FIELD THAT WAS TRYING TO DEVELOP HAS NOW ESSENTIALLY DISSIPATED AS THE BOUNDARY LAYER HAS MIXED UP INTO THE SIGNIFICANTLY DRIER AIR ALOFT. EXPECT MOSTLY SUNNY SKIES TO NOW PREVAIL FOR THE REMAINDER OF THE DAYLIGHT HOURS. .SHORT TERM (TONIGHT THROUGH SATURDAY)... TONIGHT... SHORTWAVE ENERGY RIDING NORTHWARD FROM THE WESTERN GULF OF MEXICO TO THE FLORIDA PANHANDLE/GEORGIA VICINITY WILL DE-AMPLIFY THE UPPER RIDGE AND BEGIN TO SHIFT ITS AXIS SOUTH AND SOUTHEAST. BY MORNING THE UPPER RIDGE AXIS WILL BE DOWN OVER SOUTH FLORIDA. THE SURFACE RIDGE WILL REMAIN IN PLACE WITH A LIGHT SOUTHEAST FLOW OVER THE AREA. THIS FLOW LOOKS TO REMAIN STRONG ENOUGH (ESPECIALLY JUST ABOVE THE SURFACE) TO SUPPRESS ANY SIGNIFICANT FOG DEVELOPMENT. THIS IS SHOWN IN THE SREF VISIBILITY PROBS OVERNIGHT WHICH ARE UNDER 10% FOR VIS < 3 MILES. A MILD NIGHT UPCOMING WITH LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S. SHOULD GET DOWN INTO THE MIDDLE 60S FOR INLAND LEVY COUNTY. NORMALLY WARMER SPOTS ALONG THE COAST SUCH AS ST PETE WILL HOLD IN THE MIDDLE 70S. SATURDAY... A DECENT DAY IN TERMS OF SENSIBLE WEATHER ON TAP TO START OUT THE WEEKEND. UPPER RIDGE AXIS WILL HAVE SHIFTED SOUTH OF THE AREA...SO A LITTLE LESS SYNOPTIC SUPPRESSION AND HENCE THE COLUMN WILL BE ABLE TO BEGIN MOISTENING THROUGH A GREATER DEPTH. SATURDAY LOOKS TO HAVE A MIX OF SUN AND CLOUDS IN THE MORNING DUE TO PASSING HIGHER LEVEL CIRRUS...AND THEN DUE TO A SCT-BKN CUMULUS FIELD DEVELOPING IN THE LATE MORNING AND AFTERNOON. OVERALL THE COLUMN IS STILL FAIRLY HOSTILE TO DEEP CONVECTION DUE TO ENTRAINMENT OF DRY AIR...HOWEVER...NOT QUITE AS HOSTILE AS TODAY AND THE PAST COUPLE OF DAYS. THEREFORE...AS THE SEA-BREEZE MOVES INLAND...THE LOW LEVEL FOCUS WILL HAVE A SLIGHTLY BETTER CHANCE OF KICKING OFF A FEW WIDELY SCT SHOWERS DURING THE MIDDLE TO LATE AFTERNOON. MOST OF THE HIRES CONVECTION ALLOWING GUIDANCE ARE SHOWING A LEAST THIS ISOLATED SHOWER VARIETY...BUT WITH BRIEF LIFE CYCLES DUE TO THE STILL FAIRLY DRY AIR ALOFT. GRIDS/FORECAST WILL SHOW A 20-30% CHANCE OF THESE LATE DAY SHOWERS...GENERALLY OVER THE INTERIOR...INLAND FROM THE I-75 CORRIDOR. TEMPERATURES SHOULD BE SIMILAR WITH WIDESPREAD UPPER 80S INLAND AND LOWER TO MIDDLE 80S AT THE BEACHES. ENJOY THE WEEKEND EVERYONE! && .MID TERM (SUNDAY)... HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE FOR THE SECOND HALF OF THE WEEKEND. THE EAST/WEST COAST SEA BREEZES SHOULD BE ENOUGH TO SPARK ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON...SO WILL INCLUDE SLIGHT CHANCE/LOW CHANCE POPS IN THE FORECAST FOR MOST LOCATIONS. HIGH TEMPERATURES WILL GENERALLY TOP OUT IN THE UPPER 80S TO LOWER 90S...WITH LOWS RANGING FROM THE MID TO UPPER 60S ACROSS THE INTERIOR COOL SPOTS TO THE LOWER 70S ALONG THE COAST. && .LONG TERM (SUNDAY NIGHT-FRIDAY)... MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH EARLY NEXT WEEK...WITH SOLUTIONS THEN DEVIATING WITH RESPECT TO THE HANDLING OF AN EASTERLY WAVE DURING THE MIDDLE TO LATTER PORTION OF NEXT WEEK. WILL FOLLOW A BLENDED APPROACH TO THE FORECAST GIVEN THE UNCERTAINTY...AND THIS WILL RESULT IN CHANCES FOR MAINLY AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE LONG TERM PERIOD. AT THIS POINT...IT APPEARS THAT THE HIGHEST PROBABILITIES FOR RAINFALL WILL FALL IN THE WEDNESDAY/THURSDAY TIME FRAME WHEN THE DEEPEST MOISTURE WILL BE IN PLACE. TEMPERATURES ARE EXPECTED TO RUN CLOSE TO NORMAL THROUGH THE LONG TERM PERIODS. && .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGH THE REST OF THE AFTERNOON AND EVENING. SOUTHEAST FLOW OVERNIGHT LOOKS TO REMAIN ELEVATED ENOUGH TO PREVENT MUCH IN THE WAY OF FOG DEVELOPMENT. NOT OUT OF THE QUESTION TO SEE A BRIEF MVFR PERIOD AT KLAL OR KPGD TOWARD SUNRISE ON SATURDAY...HOWEVER AT THIS TIME CONFIDENCE OF REDUCED VISIBILITIES AT EITHER TERMINAL ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS. && .MARINE... WINDS WILL SHIFT BACK TO THE SOUTHEAST OVERNIGHT AND BECOME BREEZY ONCE AGAIN...HOWEVER AT THIS TIME IT DOES NOT APPEAR AS THROUGH CAUTIONARY LEVEL WINDS OF 15-20 KNOTS WILL BE REACHED FOR THE MAJORITY OF THE FORECAST WATERS. WILL INCLUDE A MENTION OF EXERCISE CAUTION FOR ONLY THE WATERS OFF CHARLOTTE AND LEE COUNTIES WHERE THE BEST SETUP FOR THE NOCTURNAL WIND SURGE WILL EXIST. THIS CONTINUED PATTERN OF ONSHORE AFTERNOON WINDS AND OFFSHORE SLIGHTLY STRONGER FLOW AT NIGHT AND DURING THE EARLY MORNING HOURS WILL CONTINUE THROUGH THE UPCOMING WEEKEND AS HIGH PRESSURE REMAINS PARKED TO THE NORTH OF THE FORECAST WATERS. && .FIRE WEATHER... LOW LEVEL MOISTURE WILL INCREASE FURTHER INTO THE WEEKEND PREVENTING RELATIVE HUMIDITY FROM REACHING CRITICAL LEVELS EITHER SATURDAY OR SUNDAY. THERE WILL BE BETTER CHANCES FOR A FEW AFTERNOON STORMS ALONG THE SEA-BREEZE THIS WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... TPA 73 89 73 89 / 0 10 0 20 FMY 72 91 71 91 / 0 10 10 20 GIF 70 90 71 91 / 0 30 20 20 SRQ 71 89 71 88 / 0 10 10 10 BKV 67 90 66 90 / 10 10 10 20 SPG 74 88 74 88 / 0 10 10 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...MROCZKA MID TERM/LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
605 PM EDT FRI MAY 9 2014 .SYNOPSIS... HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC WILL WEAKEN SATURDAY AS A DISSIPATING FRONTAL SYSTEM MOVES INTO THE AREA. HIGH PRESSURE REGAINS CONTROL FOR THE BEGINNING OF NEXT WEEK. ANOTHER FRONT IS EXPECTED TO AFFECT THE REGION LATE NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... HEADING INTO THIS EVENING...THE SURFACE RIDGE WILL CONTINUE TO EXTEND INTO THE FORECAST AREA FROM THE ATLANTIC. SATELLITE TRENDS SHOW CONSIDERABLE MID AND UPPER CLOUDINESS MOVING ACROSS THE REGION EARLY THIS EVENING. A WEAK MID-LEVEL SHORTWAVE TROUGH...A LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS DAYTIME HEATING HAS PRODUCED A FEW LIGHT SHOWERS ACROSS THE WRN MIDLANDS/NRN CSRA. MAIN AREA OF SHOWERS/THUNDERSTORMS REMAIN WELL WEST OF THE AREA CLOSER TO THE COLD FRONT ACROSS WESTERN NC INTO NRN GA. WILL CONTINUE WITH A MENTION OF A SLIGHT CHANCE OF A SHOWER/ISO THUNDER THROUGH THE EVENING HOURS. OVERNIGHT...THE MODELS INDICATE AN INCREASE IN MOISTURE...BUT THE DEEPER MOISTURE REMAINS WEST OF THE AREA. THERE MAY BE AN INCREASE IN INSTABILITY ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH. HOWEVER...MOISTURE SHOULD REMAIN LIMITED AND ANY CONVERGENCE ASSOCIATED WITH A LEE-SIDE TROUGH SHOULD BE WEAK. THE SHOWER OR THUNDERSTORM CHANCE IS LOW. THE NAM AND GFS MOS HAVE POPS LESS THAN 20 PERCENT. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... THE MODELS INDICATE MOISTURE SATURDAY ASSOCIATED WITH THE REMNANTS OF A COLD FRONT. PRECIPITABLE WATER IS FORECAST TO INCREASE TO AROUND 1.5 INCHES WITH WEAK LIFT AHEAD OF THE BROAD UPPER-LEVEL TROUGH. THERE SHOULD ALSO BE LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH. KEPT CHANCE POPS SATURDAY. THE GUIDANCE CONSENSUS SUPPORTS POPS AROUND 30 PERCENT. THUNDERSTORMS MAY LINGER SATURDAY EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT PLUS HEATING. THE MODELS ARE CONSISTENT SHIFTING DIMINISHING MOISTURE EAST SATURDAY NIGHT WITH H5 HEIGHTS BUILDING. THE MODELS SHOW THE RIDGE REMAINING DOMINATE THROUGH SUNDAY NIGHT WITH LITTLE MOISTURE. THE NAM AND GFS MOS SUPPORT POPS LESS THAN 20 PERCENT LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT. USED THE WARMER TEMPERATURE GUIDANCE BECAUSE OF RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. THE LOW TEMPERATURE GUIDANCE WAS CLOSE. && .LONG TERM /MONDAY THROUGH FRIDAY/... MODELS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN THE PERIOD BUT THEN BEGIN TO DIFFER LATER IN THE WEEK. THE GFS MOVES THE UPPER LEVEL TROF AND SFC CDFNT OUT EARLIER WHILE THE ECMWF IS SLOWER BY 24HRS. AS A RESULT CHANCES OF RAIN AND TEMPS ARE DIFFERENT. HAVE TAKEN AN AVERAGE OF THE MOS GUIDANCE FOR EACH MODEL DAYS 5 THRU 7. MODELS DO KEEP IT DRY EARLY IN THE WEEK THEN THE NEXT CHANCE OF PRECIP WILL BE LATE IN THE PERIOD WHICH IS WHERE THE TIMING ISSUES COME IN. MAX TEMPERATURES WILL BE AROUND 90 MONDAY AND TUESDAY WITH UPPER 80S WEDNESDAY COOLING INTO THE UPPER 70S TO LOWER 80S THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE 60S MONDAY THROUGH THURSDAY AND IN THE 50S FRIDAY. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... HIGH-LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS THE TAF SITES THROUGH THE PERIOD IN THE SOUTHWEST FLOW ALOFT. CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS MID-LEVEL SHORTWAVE TROUGH COULD HELP SUPPORT THUNDERSTORMS BUT THE CHANCE IS LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE HRRR INDICATES JUST ISOLATED COVERAGE LATE THIS AFTERNOON AND THE CHANCE IS MUCH TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. MIXING HAS RESULTED IN WIND GUSTS AROUND 20 KNOTS THIS AFTERNOON. DIMINISHED MIXING BEGINNING AROUND SUNSET SHOULD RESULT IN LESS WIND. CLOUDINESS AND A LITTLE MIXING SHOULD LIMIT FOG DURING THE EARLY MORNING HOURS SATURDAY. THE GFS AND NAM MOS INDICATE VFR CONDITIONS. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH TUESDAY. && .CLIMATE... TODAY MARKS THE 5TH DAY IN A ROW OF 90 DEGREES OR HIGHER AT BOTH AUGUSTA BUSH FIELD AND COLUMBIA METRO. THIS IS NOT A RECORD. AT AUGUSTA...THE RECORD FOR THE MONTH OF MAY IS 13 CONSECUTIVE DAYS IN 1998 AND 1965. AT COLUMBIA...THE RECORD FOR THE MONTH OF MAY IS 13 CONSECUTIVE DAYS IN 1962. TEMPERATURES ARE EXPECTED TO NOT REACH 90 DEGREES SATURDAY WITH AFTERNOON HIGHS IN THE MID/UPPER 80S EXPECTED. AGS... 5TH...92 6TH...91 7TH...91 8TH...91 9TH...90 CAE... 5TH...95 TIED THE RECORD HIGH OF 95 SET IN 2012 AND 1955 6TH...93 7TH...94 8TH...95 9TH...93 && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 77
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
315 PM EDT FRI MAY 9 2014 SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... MOIST SW FLOW ALOFT HAS MOVED OVER THE FORECAST AREA WITH THE DEEPEST MOISTURE OVER N AND PORTIONS OF CENTRAL GA WITH AN UPPER SHORT WAVE IN THE FLOW. GFS AND NAM ARE INCONSISTENT WITH HOW FAR SE TO TAKE THE DEEP MOISTURE WITH THE GFS MUCH MORE AGGRESSIVE MOVING THE MOISTURE TO THE SE. HI-RES REFLECTIVITY FORECASTS FROM THE WRF AND HRRR WEAKEN THE LINE OF SHOWERS AND STORMS OVER NW GA EARLY THIS EVENING AND WITH ONLY WEAK INSTABILITY OVER N GA...THIS SEEMS REASONABLE. THUNDERSTORM CHANCES EXPECTED TO DIMINISH FIRST BUT THE SHOWER CHANCES MAY NOT BE FAR BEHIND. KEPT POPS IN THE LIKELY CATEGORY OVER N GA ALL NIGHT AND THIS MAY BE OVERDONE. ALSO AM HARD PRESSED TO INCLUDE POPS TOO FAR SE AS THE BEST MOISTURE AND DYNAMICS DO NOT GET THAT FAR BUT ANY DEVELOPMENT WILL NEED TO BE WATCHED THIS AFTERNOON AND OVERNIGHT. GUIDANCE NOT BIG ON POPS SATURDAY INTO SATURDAY NIGHT WITH THE UPPER FLOW BECOMING MORE ZONAL. WITH MOISTURE AND SOME INSTABILITY EXPECTED...A FLAIR-UP OF SCATTERED SHOWERS AND THUNDERSTORMS SEEMS REASONABLE FOR MUCH OF THE FORECAST AREA SATURDAY INTO SATURDAY NIGHT. FORECAST LOW TEMPERATURES RUNNING 5-8 DEGREES ABOVE NORMAL TONIGHT AND SATURDAY NIGHT. FORECAST HIGH TEMPERATURES RUNNING 2-4 DEGREES ABOVE NORMAL ON SATURDAY. BDL .LONG TERM /SUNDAY THROUGH FRIDAY/... NOT MUCH CHANGE NEEDED AT THIS TIME TO THE FORECAST FOR THE EXTENDED AS WE STILL LOOK FOR THE NEXT SIGNIFICANT SYSTEM TO AFFECT THE AREA BY MID WEEK NEXT WEEK. THIS FAR OUT...CURRENT GRIDS HAVE A GOOD HANDLE ON THIS AND NO CHANGES ARE PLANNED. FOR THE INITIAL PORTION OF THE EXTENDED...PLAN TO INCREASE POPS THE FIRST HALF OF SATURDAY NIGHT AS RESIDUAL CONVECTION LOOKS TO HANG ON AFTER SUNSET. DEESE && .PREV DISCUSSION... /ISSUED 131 PM EDT FRI MAY 9 2014/ LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... ECMWF AND GFS CONTINUE TO SHOW HIGH PRESSURE BUILDING FROM THE EAST ON SUNDAY AND MONDAY AS A LONG-WAVE TROUGH DEEPENS OVER THE WESTERN THIRD OF THE COUNTRY. DESPITE THE INCREASED RIDGING... MODELS SHOW 800-1500 J/KG OF SBCAPE DURING MAX HEATING EACH DAY... WARRANTING A SLIGHT CHANCE OF THUNDERSTORMS EACH AFTERNOON... ESPECIALLY ACROSS NORTH GA WHERE OROGRAPHIC LIFT MAY ENHANCE DEVELOPMENT. OTHERWISE... THE NEXT BEST CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS CONTINUES TO BE TUESDAY THROUGH POSSIBLY EARLY THURSDAY AS THE AFOREMENTIONED LONG-WAVE TROUGH KICKS EASTWARD AND DRAGS A COLD FRONT ACROSS THE STATE SOMETIME MID WEEK. THERE IS SOME TIMING DIFFERENCES BETWEEN THE MODELS... WITH THE FASTER GFS PUSHING THE COLD FRONT INTO NW GA TUESDAY NIGHT AND CLEARING THE FORECAST AREA BY WEDNESDAY EVENING. THE SLOWER ECMWF SHOWS THE FRONT ENTERING NW GA WEDNESDAY AFTERNOON...THEN CLEARING THE FORECAST AREA SOMETIME THURSDAY MORNING. PREFERRING THE MORE CONSISTENT GFS... WILL CONTINUE TO SHOW THE GREATER POPS AND THUNDERSTORM CHANCES ON WEDNESDAY. HOWEVER... DID ADD A SLIGHT CHANCE OF SHOWERS EARLY ON THURSDAY AS CLEARING MAY BE SLOW. ALTHOUGH THE GREATER UPPER SUPPORT APPEARS TO LIFT ACROSS THE OHIO VALLEY REGION... THIS SYSTEM STILL HAS A POTENTIAL TO PRODUCE A FEW STRONG STORMS AHEAD OF THE FRONT... AS BOTH MODELS SHOW 800-1200 J/KG OF CAPE AHEAD OF THE FRONT BY WEDNESDAY AFTERNOON... WITH THE FASTER GFS SUGGESTING CENTRAL GA WOULD HAVE THE GREATER STORM THREAT... WHILE THE SLOWER ECMWF WOULD BE FOCUSED MORE ON NORTH GA ON WEDNESDAY. WITH SUCH UNCERTAINTY ON TIMING AND STRENGTH... ALL INTEREST ARE ENCOURAGED TO CLOSELY MONITOR LATER FORECAST CONCERNING THIS SYSTEM. 39 AVIATION... 18Z UPDATE... MOST VFR CONDITIONS WITH SOME MVFR CEILINGS. LOW CONFIDENCE FOR CEILINGS...VSBYS AND WEATHER THROUGH THE PERIOD. THINKING IS MOST SHOWERS AND STORMS WILL BE N AND W OF ATL INTO TONIGHT. SURFACE WINDS SSW AROUND 10 KTS WITH OCCASIONAL GUSTS TO 20 KTS...DIMINISHING EARLY EVENING. //ATL CONFIDENCE...18Z UPDATE... LOW CONFIDENCE CEILINGS...VSBYS AND WEATHER. MEDIUM-HIGH CONFIDENCE WINDS. BDL && .PRELIMINARY POINT TEMPS/POPS... ATHENS 64 83 61 86 / 20 50 40 20 ATLANTA 64 82 65 84 / 40 40 30 20 BLAIRSVILLE 59 75 58 80 / 60 60 40 20 CARTERSVILLE 62 82 61 86 / 60 40 40 20 COLUMBUS 65 85 65 88 / 20 40 20 20 GAINESVILLE 63 79 62 84 / 50 50 40 20 MACON 64 85 63 88 / 10 30 20 20 ROME 63 81 61 87 / 60 40 40 20 PEACHTREE CITY 62 83 61 85 / 30 40 20 20 VIDALIA 67 86 67 89 / 10 20 20 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BDL LONG TERM....DEESE AVIATION...BDL
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
243 PM EDT FRI MAY 9 2014 .SYNOPSIS... HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC WILL WEAKEN SATURDAY AS A DISSIPATING FRONTAL SYSTEM MOVES INTO THE AREA. HIGH PRESSURE REGAINS CONTROL FOR THE BEGINNING OF NEXT WEEK. ANOTHER FRONT IS EXPECTED TO AFFECT THE REGION LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...THE SURFACE RIDGE WILL CONTINUE TO EXTEND INTO THE FORECAST AREA FROM THE ATLANTIC. THE LOWER LEVELS SHOULD REMAIN RELATIVELY DRY. SATELLITE TRENDS SHOW CONSIDERABLE MID AND UPPER CLOUDINESS MOVING INTO THE AREA IN THE SOUTHWEST FLOW AHEAD OF THE TROUGH. A WEAK MID-LEVEL SHORTWAVE TROUGH...A LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS HEATING WILL HELP SUPPORT A FEW THUNDERSTORMS MAINLY IN THE WEST PART CLOSER TO THE DEEPER MOISTURE. STILL...WITH JUST SHALLOW MOISTURE AND WEAK FORCING IN THE FORECAST AREA BELIEVE COVERAGE WILL REMAIN ISOLATED. THE LATEST HRRR INDICATES JUST ISOLATED SHOWERS OR THUNDERSTORMS. TONIGHT...THE MODELS INDICATE AN INCREASE IN MOISTURE...BUT THE DEEPER MOISTURE REMAINS WEST OF THE AREA. THERE MAY BE AN INCREASE IN INSTABILITY ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH. HOWEVER...MOISTURE SHOULD REMAIN LIMITED AND ANY CONVERGENCE ASSOCIATED WITH A LEE-SIDE TROUGH SHOULD BE WEAK. THE SHOWER OR THUNDERSTORM CHANCE IS LOW. THE NAM AND GFS MOS HAVE POPS LESS THAN 20 PERCENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... THE MODELS INDICATE MOISTURE SATURDAY ASSOCIATED WITH THE REMNANTS OF A COLD FRONT. PRECIPITABLE WATER IS FORECAST TO INCREASE TO AROUND 1.5 INCHES WITH WEAK LIFT AHEAD OF THE BROAD UPPER-LEVEL TROUGH. THERE SHOULD ALSO BE LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH. KEPT CHANCE POPS SATURDAY. THE GUIDANCE CONSENSUS SUPPORTS POPS AROUND 30 PERCENT. THUNDERSTORMS MAY LINGER SATURDAY EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT PLUS HEATING. THE MODELS ARE CONSISTENT SHIFTING DIMINISHING MOISTURE EAST SATURDAY NIGHT WITH H5 HEIGHTS BUILDING. THE MODELS SHOW THE RIDGE REMAINING DOMINATE THROUGH SUNDAY NIGHT WITH LITTLE MOISTURE. THE NAM AND GFS MOS SUPPORT POPS LESS THAN 20 PERCENT LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT. USED THE WARMER TEMPERATURE GUIDANCE BECAUSE OF RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. THE LOW TEMPERATURE GUIDANCE WAS CLOSE. && .LONG TERM /MONDAY THROUGH THURSDAY/... MODELS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN THE PERIOD BUT THEN BEGIN TO DIFFER LATER IN THE WEEK. THE GFS MOVES THE UPPER LEVEL TROF AND SFC CDFNT OUT EARLIER WHILE THE ECMWF IS SLOWER BY 24HRS. AS A RESULT CHANCES OF RAIN AND TEMPS ARE DIFFERENT. HAVE TAKEN AN AVERAGE OF THE MOS GUIDANCE FOR EACH MODEL DAYS 5 THRU 7. MODELS DO KEEP IT DRY EARLY IN THE WEEK THEN THE NEXT CHANCE OF PRECIP WILL BE LATE IN THE PERIOD WHICH IS WHERE THE TIMING ISSUES COME IN. MAX TEMPERATURES WILL BE AROUND 90 MONDAY AND TUESDAY WITH UPPER 80S WEDNESDAY COOLING INTO THE UPPER 70S TO LOWER 80S THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE 60S MONDAY THROUGH THURSDAY AND IN THE 50S FRIDAY. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... HIGH-LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS THE TAF SITES THROUGH THE PERIOD IN THE SOUTHWEST FLOW ALOFT. CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS MID-LEVEL SHORTWAVE TROUGH COULD HELP SUPPORT THUNDERSTORMS BUT THE CHANCE IS LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE HRRR INDICATES JUST ISOLATED COVERAGE LATE THIS AFTERNOON AND THE CHANCE IS MUCH TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. MIXING HAS RESULTED IN WIND GUSTS AROUND 20 KNOTS THIS AFTERNOON. DIMINISHED MIXING BEGINNING AROUND SUNSET SHOULD RESULT IN LESS WIND. CLOUDINESS AND A LITTLE MIXING SHOULD LIMIT FOG DURING THE EARLY MORNING HOURS SATURDAY. THE GFS AND NAM MOS INDICATE VFR CONDITIONS. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH TUESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
200 PM EDT FRI MAY 9 2014 .SYNOPSIS... HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC WILL WEAKEN SATURDAY AS A DISSIPATING FRONTAL SYSTEM MOVES INTO THE AREA. HIGH PRESSURE REGAINS CONTROL FOR THE BEGINNING OF NEXT WEEK. ANOTHER FRONT IS EXPECTED TO AFFECT THE REGION LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...THE SURFACE RIDGE WILL CONTINUE TO EXTEND INTO THE FORECAST AREA FROM THE ATLANTIC. THE LOWER LEVELS SHOULD REMAIN RELATIVELY DRY. SATELLITE TRENDS SHOW CONSIDERABLE MID AND UPPER CLOUDINESS MOVING INTO THE AREA IN THE SOUTHWEST FLOW AHEAD OF THE TROUGH. A WEAK MID-LEVEL SHORTWAVE TROUGH...A LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS HEATING COULD POSSIBLY SUPPORT THUNDERSTORMS LATE...BUT THE CHANCE IS VERY LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE LATEST HRRR INDICATES JUST ISOLATED SHOWERS LATE IN THE DAY. THE FORECAST APPEARS ON TRACK WITH POPS LESS THAN 20 PERCENT. IT SHOULD BE A LITTLE COOLER THAN PREVIOUS DAYS BECAUSE OF CLOUDINESS. HOWEVER...IT WILL LIKELY NOT BE NOTICEABLE BECAUSE OF A SLIGHT INCREASE IN HUMIDITY. TONIGHT...THE MODELS INDICATE AN INCREASE IN MOISTURE...BUT THE DEEPER MOISTURE REMAINS WEST OF THE AREA. THERE MAY BE AN INCREASE IN INSTABILITY ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH. HOWEVER...MOISTURE SHOULD REMAIN LIMITED AND ANY CONVERGENCE ASSOCIATED WITH A LEE-SIDE TROUGH SHOULD BE WEAK. THE SHOWER OR THUNDERSTORM CHANCE IS LOW. THE NAM AND GFS MOS HAVE POPS LESS THAN 20 PERCENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... THE MODELS INDICATE MOISTURE SATURDAY ASSOCIATED WITH THE REMNANTS OF A COLD FRONT. PRECIPITABLE WATER IS FORECAST TO INCREASE TO AROUND 1.5 INCHES WITH WEAK LIFT AHEAD OF THE BROAD UPPER-LEVEL TROUGH. THERE SHOULD ALSO BE LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH. KEPT CHANCE POPS SATURDAY. THE GUIDANCE CONSENSUS SUPPORTS POPS AROUND 30 PERCENT. THUNDERSTORMS MAY LINGER SATURDAY EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT PLUS HEATING. THE MODELS ARE CONSISTENT SHIFTING DIMINISHING MOISTURE EAST SATURDAY NIGHT WITH H5 HEIGHTS BUILDING. THE MODELS SHOW THE RIDGE REMAINING DOMINATE THROUGH SUNDAY NIGHT WITH LITTLE MOISTURE. THE NAM AND GFS MOS SUPPORT POPS LESS THAN 20 PERCENT LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT. USED THE WARMER TEMPERATURE GUIDANCE BECAUSE OF RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. THE LOW TEMPERATURE GUIDANCE WAS CLOSE. && .LONG TERM /MONDAY THROUGH THURSDAY/... MODELS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN THE PERIOD BUT THEN BEGIN TO DIFFER LATER IN THE WEEK. THE GFS MOVES THE UPPER LEVEL TROF AND SFC CDFNT OUT EARLIER WHILE THE ECMWF IS SLOWER BY 24HRS. AS A RESULT CHANCES OF RAIN AND TEMPS ARE DIFFERENT. HAVE TAKEN AN AVERAGE OF THE MOS GUIDANCE FOR EACH MODEL DAYS 5 THRU 7. MODELS DO KEEP IT DRY EARLY IN THE WEEK THEN THE NEXT CHANCE OF PRECIP WILL BE LATE IN THE PERIOD WHICH IS WHERE THE TIMING ISSUES COME IN. MAX TEMPERATURES WILL BE AROUND 90 MONDAY AND TUESDAY WITH UPPER 80S WEDNESDAY COOLING INTO THE UPPER 70S TO LOWER 80S THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE 60S MONDAY THROUGH THURSDAY AND IN THE 50S FRIDAY. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... HIGH-LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS THE TAF SITES THROUGH THE PERIOD IN THE SOUTHWEST FLOW ALOFT. CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS MID-LEVEL SHORTWAVE TROUGH COULD HELP SUPPORT THUNDERSTORMS BUT THE CHANCE IS VERY LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE HRRR INDICATES JUST ISOLATED COVERAGE LATE THIS AFTERNOON AND THE CHANCE IS MUCH TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. THE NAM BUFKIT MOMENTUM TRANSFER TOOL...GFS LAMP...AND KCAE 88D VAD WIND PROFILE INDICATE WIND GUSTS 20 TO 25 KNOTS THIS AFTERNOON. THE HIGH CLOUDINESS SHOULD LIMIT MIXING SOMEWHAT SO FORECASTED GUSTS NEAR THE LOWER END OF THE RANGE. CLOUDINESS AND MIXING SHOULD LIMIT FOG DURING THE EARLY MORNING HOURS SATURDAY. THE GFS AND NAM MOS INDICATE VFR CONDITIONS. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH TUESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
105 PM EDT FRI MAY 9 2014 .SYNOPSIS... HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC WILL WEAKEN SATURDAY AS A DISSIPATING FRONTAL SYSTEM MOVES INTO THE AREA. HIGH PRESSURE REGAINS CONTROL FOR THE BEGINNING OF NEXT WEEK. ANOTHER FRONT IS EXPECTED TO AFFECT THE REGION LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...THE SURFACE RIDGE WILL CONTINUE TO EXTEND INTO THE FORECAST AREA FROM THE ATLANTIC. THE LOWER LEVELS SHOULD REMAIN RELATIVELY DRY. SATELLITE TRENDS SHOW CONSIDERABLE MID AND UPPER CLOUDINESS MOVING INTO THE AREA IN THE SOUTHWEST FLOW AHEAD OF THE TROUGH. A WEAK MID-LEVEL SHORTWAVE TROUGH...A LITTLE LOW- LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS HEATING COULD POSSIBLY SUPPORT THUNDERSTORMS LATE...BUT THE CHANCE IS VERY LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE LATEST HRRR INDICATES JUST ISOLATED SHOWERS LATE IN THE DAY. THE FORECAST APPEARS ON TRACK WITH POPS LESS THAN 20 PERCENT. IT SHOULD BE A LITTLE COOLER THAN PREVIOUS DAYS BECAUSE OF CLOUDINESS. HOWEVER...IT WILL LIKELY NOT BE NOTICEABLE BECAUSE OF A SLIGHT INCREASE IN HUMIDITY. TONIGHT...THE MODELS INDICATE AN INCREASE IN MOISTURE...BUT THE DEEPER MOISTURE REMAINS WEST OF THE AREA. THERE MAY BE AN INCREASE IN INSTABILITY ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH. HOWEVER...MOISTURE SHOULD REMAIN LIMITED AND ANY CONVERGENCE ASSOCIATED WITH A LEE-SIDE TROUGH SHOULD BE WEAK. THE SHOWER OR THUNDERSTORM CHANCE IS LOW. THE NAM AND GFS MOS HAVE POPS LESS THAN 20 PERCENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... THE MODELS INDICATE AN INCREASE IN MOISTURE SATURDAY ASSOCIATED WITH THE REMNANTS OF A COLD FRONT. PRECIPITABLE WATER IS FORECAST TO INCREASE TO AROUND 1.5 INCHES WITH WEAK LIFT AHEAD OF THE BROAD UPPER-LEVEL TROUGH. THERE SHOULD ALSO BE LITTLE LOW-LEVEL CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH. KEPT CHANCE POPS SATURDAY. THE GUIDANCE CONSENSUS SUPPORTS POPS AROUND 30 PERCENT. THUNDERSTORMS MAY LINGER SATURDAY EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT PLUS HEATING. THE MODELS ARE CONSISTENT SHIFTING DIMINISHING MOISTURE EAST SATURDAY NIGHT WITH H5 HEIGHTS BUILDING. THE MODELS SHOW THE RIDGE REMAINING DOMINATE THROUGH SUNDAY NIGHT WITH LITTLE MOISTURE. THE NAM AND GFS MOS SUPPORT POPS LESS THAN 20 PERCENT LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT. USED THE WARMER TEMPERATURE GUIDANCE BECAUSE OF RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. THE LOW TEMPERATURE GUIDANCE WAS CLOSE. && .LONG TERM /MONDAY THROUGH FRIDAY/... MODELS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN THE PERIOD BUT THEN BEGIN TO DIFFER LATER IN THE WEEK. THE GFS MOVES THE UPPER LEVEL TROF AND SFC CDFNT OUT EARLIER WHILE THE ECMWF IS SLOWER BY 24HRS. AS A RESULT CHANCES OF RAIN AND TEMPS ARE DIFFERENT. HAVE TAKEN AN AVERAGE OF THE MOS GUIDANCE FOR EACH MODEL DAYS 5 THRU 7. MODELS DO KEEP IT DRY EARLY IN THE WEEK THEN THE NEXT CHANCE OF PRECIP WILL BE LATE IN THE PERIOD WHICH IS WERE THE TIMING ISSUES COME IN. MAX TEMPERATURES BE AROUND 90 MONDAY AND TUESDAY WITH UPPER 80S WEDNESDAY COOLING INTO THE UPPER 70S TO LOWER 80S THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE 60S MONDAY THROUGH THURSDAY AND IN THE 50S FRIDAY. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... HIGH-LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS THE TAF SITES THROUGH THE PERIOD IN THE SOUTHWEST FLOW ALOFT. CONVERGENCE ASSOCIATED WITH A WEAK LEE-SIDE TROUGH PLUS MID-LEVEL SHORTWAVE TROUGH COULD HELP SUPPORT THUNDERSTORMS BUT THE CHANCE IS VERY LOW BECAUSE OF SHALLOW MOISTURE AND WEAK FORCING. THE HRRR INDICATES JUST ISOLATED COVERAGE LATE THIS AFTERNOON AND THE CHANCE IS MUCH TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. THE NAM BUFKIT MOMENTUM TRANSFER TOOL...GFS LAMP...AND KCAE 88D VAD WIND PROFILE INDICATE WIND GUSTS 20 TO 25 KNOTS THIS AFTERNOON. THE HIGH CLOUDINESS SHOULD LIMIT MIXING SOMEWHAT SO FORECASTED GUSTS NEAR THE LOWER END OF THE RANGE. CLOUDINESS AND MIXING SHOULD LIMIT FOG DURING THE EARLY MORNING HOURS SATURDAY. THE GFS AND NAM MOS INDICATE VFR OR MVFR CONDITIONS WITH MVFR FOG CONFINED TO THE RIVER-VALLEY TERMINALS OF AGS AND OGB. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH TUESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
202 PM CDT FRI MAY 9 2014 .DISCUSSION... 1125 AM CDT WE CONTINUE TO MONITOR SCATTERED CONVECTION MAINLY ALONG AND EAST OF INTERSTATE 57 GOING INTO AFTERNOON WITH A SLIGHT RISK FOR SEVERE STORMS. NO MAJOR CHANGES MADE TO AFTERNOON TEMPERATURES OR STORM CHANCES...WITH SOME SUBTLE ADJUSTMENTS TO HOURLY TRENDS AND SPATIAL COVERAGE. MAIN SWATH OF MORNING PRECIPITATION ON THE LOW-LEVEL JET HAS SHIFTED EAST OF THE AREA. THE SURFACE COLD FRONT AND ASSOCIATED WESTERLY WIND SHIFT AND DRY ADVECTION IS LOCATED FROM NEAR WAUKEGAN TO JUST WEST OF PONTIAC AS OF 1115 AM. SOME SCATTERING OF CLOUDS IN ADVANCE OF THIS ALONG WITH CONTINUED WARM/MOIST ADVECTION AHEAD OF THE FRONT HAS LED TO DESTABILIZATION AHEAD OF THE FRONT WITHIN A MOISTURE-RICH WARM SECTOR. SCATTERED CONVECTION FROM THE SOUTH CHICAGO METRO TO KANKAKEE LOOKS SUPPORTED BY INCREASING LOW-LEVEL CONVERGENCE...WHICH SHOULD CONTINUE WITH THE BOUNDARY ADVANCING THIS AFTERNOON. AN UPSTREAM SHORT WAVE IN EASTERN MO AND BROADER FORCING FOR ASCENT WITH UPPER JET SUPPORT WOULD FAVOR INCREASING SHEAR AND A POTENTIAL INTENSIFICATION IN THE SCATTERED CONVECTION AFTER 1 PM OR SO...INCLUDING THE POSSIBILITY OF A FEW SEVERE STORMS IN THE SOUTHEAST FORECAST AREA CONCURRENT WITH THE SPC SLIGHT RISK. EARLIER CONVECTION THIS MORNING HAD PRODUCED SOME 40-52 MPH GUSTS ACROSS FAR NORTHWEST INDIANA AND ANY AFTERNOON CONVECTION COULD ALSO BE SPORADICALLY GUSTY. COOLING MID-LEVEL TEMPS AND STRONGER UPDRAFTS MAY SUPPORT SOME MARGINALLY SEVERE HAIL WITH THE STRONGEST STORMS AS WELL. MTF //PREV DISCUSSION... 335 AM CDT MULTIPLE FORECAST CONCERNS THIS GO AROUND INCLUDING PRECIP CHANCES TODAY...CONVECTIVE POTENTIAL LATER IN THE WEEKEND...MAGNITUDE OF WARM UP AHEAD OF SYSTEM LATER THIS WEEKEND/EARLY NEXT WEEK...AND THEN TRANSITION TOWARD UNSEASONABLY COOL/UNSETTLED WEATHER NEXT WEEK. COLD FRONT IS APPROACHING THE MISSISSIPPI RIVER EARLY THIS MORNING WITH SOUTHERLY WINDS PUMPING WARM AND RATHER HUMID AIR NORTH INTO THE AREA. NUMEROUS SUBTLE SHORTWAVES CONTINUE MOVE NE ACROSS THE REGION RESULTING IN WAVES OF SHOWERS/T-STORMS. ONE WAVE IS MOVING EAST OF THE AREA AT 08Z...HOWEVER SHORT RANGE GUIDANCE HAS BEEN PRETTY INSISTENT THAT ANOTHER SHORTWAVE OVER MISSOURI WILL RESULT IN AN INCREASE IN PRECIP THE NEXT SEVERAL HOURS...MOVING INTO THE SOUTHEAST HALF TO TWO THIRDS OF THE CWA EARLY THIS MORNING. EXTENSIVE CIRRUS MAKES SEEING THIS WAVE ON GOES IMAGERY IMPOSSIBLE...BUT RECENT UPTICK IN SHOWERS OVER MISSOURI LENDS SOME CREDENCE TO THE MODEL GUIDANCE AND PLAN TO CARRY HIGH POPS FOR EARLY THIS MORNING. INSTABILITY IS FAIRLY WEAK SO NOT EXPECTING MUCH MORE THAN JUST AN ISOLATED THUNDERSTORM OR TWO WITH MAINLY JUST SHOWERS EARLY THIS MORNING. COLD FRONT WILL SWEEP ACROSS THE AREA LATER THIS MORNING INTO THE AFTERNOON USHERING IN A MUCH DRIER AIR MASS...THOUGH THE COLDER AIR LAGS SOME BEHIND THE FRONT. THE RESULT SHOULD BE BECOMING MOSTLY SUNNY WITH DRY WESTERLY WINDS LIKELY ALLOWING TEMPS TO HEAT UP NICELY WELL INTO THE 70S. THERE REMAINS A CHANCE THAT THE FRONT MAY NOT HAVE CLEARED OUR SE COUNTIES BY THE TIME CONVECTION REDEVELOPS THIS AFTERNOON...SO HAVE MAINTAINED SOME CHANCE POPS THIS AFTERNOON FAR SOUTHEAST CWA. ONCE FRONT MOVES EAST CONVECTIVE THREAT ENDS SE CWA THIS AFTERNOON WITH DRY AND MILD WEATHER EXPECTED TONIGHT INTO SATURDAY. WHILE PRESSURE GRADIENT WILL SUPPORT WEST WINDS SATURDAY AFTERNOON...AM CONCERNED THAT GRADIENT WILL BE WEAK ENOUGH TO ALLOW A WEAK AFTERNOON LAKE BREEZE TO DEVELOP AND CAUSING TEMPS NEAR THE LAKE TO FALL OFF SOME IN THE AFTERNOON. ANOTHER FAIRLY STRONG SHORTWAVE IS PROGGED TO PASS TO OUR NORTHWEST SATURDAY NIGHT WITH STRENGTHENING WARM AIR ADVECTION REGIME SETTING THE STAGE FOR SHOWERS/THUNDERSTORMS TO DEVELOP AGAIN SATURDAY NIGHT. WILL LIKELY SEE SOME BREAK IN THE CONVECTION SUNDAY...WITH MUCH OF THE DAY POTENTIALLY ENDING UP DRY AND WARM AS WE END UP BETWEEN SYSTEMS. SYNOPTIC WARM FRONT IS PROGGED TO BE NORTH OF THE AREA...BUT POTENTIAL EXISTS FOR NOCTURNAL CONVECTION SAT NIGHT TO AUGMENT THE FRONTAL POSITION AND THAT RAISES SOME UNCERTAINTIES WITH REGARDS TO TEMPS...ESPECIALLY ALONG THE LAKE BREEZE PRONE LAKE SIDE AREAS. NEXT STRONG SHORTWAVE IS EXPECTED TO EMERGE OUT ONTO THE CENTRAL PLAINS LATER SUNDAY WITH CYCLOGENESIS TO OUR WEST SUNDAY NIGHT LIKELY TO RESULT IN A SHARPENING SECONDARY WARM FRONT DEVELOPING TO OUR SOUTH. SHOWERS/THUNDERSTORMS LOOK TO BE A GOOD BET IN THE WAA REGIME SUNDAY NIGHT WITH SUFFICIENT SHEAR/INSTABILITY LIKELY TO BE PRESENT TO SUPPORT SOME SEVERE POTENTIAL SUNDAY NIGHT. WARM FRONT LIKELY TO MAKE IT NORTH OF THE CWA MONDAY...BUT TIMING DIFFERENCES DO EXISTS BETWEEN THE GFS AND ECMWF. LEANING TOWARD THE SLOWER TIMING OF THE ECMWF/GEM WHICH WOULD SUPPORT ANOTHER VERY WARM AND HUMID DAY MONDAY WITH MOSTLY DRY CONDITIONS BEFORE A STRONG COLD FRONT ARRIVES MONDAY NIGHT WITH INCREASING THREAT OF SHOWERS/THUNDERSTORMS. SYNOPTICALLY FAVORABLE PATTERN EXISTS FOR POTENTIALLY RESPECTABLE SEVERE WEATHER EPISODE MONDAY WITH TIMING OF THE SYSTEM DICTATING WHETHER THE GREATEST SEVERE THREAT WILL BE HERE OR TO OUR WEST. TOO SOON TO SAY FOR SURE...BUT MONDAY AND MONDAY NIGHT WARRANT CLOSE ATTENTION WITH LATER FORECASTS. BIG COLD UPPER LOW/TROUGH WILL SET UP SHOP OVER THE AREA TUESDAY THROUGH THURSDAY. VERY COLD AIR ALOFT WITH THIS UPPER LOW //-26C AT 500MB// SHOULD SUPPORT DIURNAL SCATTERED SHOWER AND POSSIBLY ISOLD T-STORM DEVELOPMENT. WHILE MUCH OF THE TIME WILL BE DRY TUES-THURS THERE COULD VERY WELL BE SOME SCTD (MAINLY DIURNAL) CONVECTION AROUND EACH DAY WHICH NECESSITATES MAINTAINING CHANCE POPS. UNSEASONABLY COOL TEMPERATURES ARE EXPECTED WITH HIGHS STRUGGLING TO REACH 60 BY WED AND THURSDAY. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WESTERLY WINDS GUSTING TO AROUND 30 KT AT TIMES THIS AFTERNOON. * POSSIBLE LAKE BREEZE SATURDAY AFTERNOON SHIFTING WINDS EASTERLY. //DISCUSSION...UPDATED 18Z... STRONG LOW PRESSURE ACROSS LAKE SUPERIOR CONTINUES TO MOVE NORTHEAST WITH AN EXTENDING COLD FRONT HAVING PASSED THE NORTHERN ILLINOIS AIRPORTS. THIS HAS TURNED WINDS MORE WEST-NORTHWEST. SCATTERING OF CLOUDS BEHIND THE FRONT SHOULD MOVE ACROSS ALL TAF SITES THIS AFTERNOON. WITH MORE EFFICIENT MIXING IN THIS REGION...GUSTS TO AROUND 30 KT HAVE BEEN OBSERVED AND SHOULD CONTINUE THIS AFTERNOON. SCATTERED STORMS ALONG THE FRONT WILL REMAIN SOUTH OF THE TAF SITES...ALTHOUGH COULD GRAZE ACROSS THE SOUTHERN TRACON AREA EARLY THIS AFTERNOON. AS THE SURFACE RIDGE PASSES OVER THE REGION LATE TONIGHT INTO EARLY SATURDAY MORNING...WIND SPEEDS WILL DIMINISH. THIS WILL AT LEAST ALLOW A LAKE BREEZE TO DEVELOP. AS SOUTHWEST WINDS KICK IN BEHIND THE FRONT IT SHOULD SLOW THE SPREAD OF THE LAKE BREEZE TO ORD AND MDW. THERE IS STILL ANTICIPATED A SYNOPTIC SHIFT TOWARD SOUTH OR SOUTHEAST-EAST LATE IN THE DAY/EARLY IN THE EVE EVEN IF THE LAKE BREEZE DOES NOT ARRIVE. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH IN WINDS THROUGH SATURDAY MORNING. * LOW ON WHETHER WINDS TURN EASTERLY DURING SATURDAY AFTERNOON. //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...SHRA/TSRA POSSIBLE. SUNDAY...PERIODS OF SHRA/TSRA POSSIBLE. MONDAY...PERIODS OF SHRA/TSRA POSSIBLE. TUESDAY THROUGH THURSDAY...CHANCE SHRA. MTF/KJB && .MARINE... 201 PM CDT AS LOW PRESSURE AND AN ASSOCIATED COLD FRONT MOVE EAST NORTHEAST ACROSS THE REGION...SOUTH TO SOUTHWEST WINDS PERSIST OVER THE LAKE. A FAIRLY TIGHT PRESSURE GRADIENT IS ALLOWING FOR A 15 TO 25 KT WIND WITH OCCASIONAL GUSTS TO 30 KT ACROSS THE LAKE. ALTHOUGH SPEEDS WILL DIMINISH ACROSS THE SOUTHERN HALF OF THE LAKE AND ILLINOIS/INDIANA NEARSHORES THIS EVENING AND OVERNIGHT...SPEEDS WILL STAY CLOSER TO THE 30 KT RANGE TONIGHT FOR THE NORTHERN HALF OF THE LAKE WHERE A SURFACE TROUGH AND TIGHTER PRESSURE GRADIENT WILL SWING THROUGH. EXPECT THE DIMINISHING TREND TO OCCUR OVER THE NORTHERN HALF OF THE LAKE ON SATURDAY AS APPROACHING SURFACE RIDGE OF HIGH PRESSURE PROVIDES MORE OF A RELAXED SURFACE PATTERN ACROSS THE LAKE. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 PM FRIDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1259 PM CDT Fri May 9 2014 .DISCUSSION... ISSUED 926 AM CDT Fri May 9 2014 Overnight convection has lifted northeastward out of the area, leaving behind only a few scattered showers along/east of the I-57 corridor this morning. Cold front is currently approaching the Illinois River. Ahead of the boundary, southwesterly winds continue with 14z/9am temps in the upper 60s/lower 70s. Meanwhile behind the front, W/NW winds have dropped the temp into the upper 50s around Galesburg. Front will only make slow progress eastward today, with additional convection likely developing ahead of it during the afternoon hours. NAM and HRRR both suggest scattered thunderstorms will develop in the instability axis along/south of I-70 by mid to late afternoon. In the meantime, relatively stable airmass in the wake of the earlier convection should keep things quiet through early afternoon. Have updated the forecast to significantly reduce POPs this morning. Will only mention isolated to scattered showers east of the Illinois River through midday, then will increase POPs to likely for showers/thunder across the SE KILX CWA this afternoon. Barnes && .AVIATION... ISSUED 1259 PM CDT Fri May 9 2014 VFR conditions will prevail through the entire 18z TAF period. A cold front currently just east of I-55 will push slowly eastward this afternoon, with scattered thunderstorms developing along and ahead of it. 1730z visible satellite imagery shows a fine line of enhanced CU well ahead of the front that could eventually develop into a broken line of convection over the next hour or two. This line is already east of all terminals except KCMI, so have opted to leave thunder mention out of the forecast at all sites at this time. Better focus for widespread convection will remain well south toward the I-70 corridor. Diurnal cloud cover will dissipate by this evening, with mostly clear skies expected overnight into Saturday morning. Winds will initially be gusty from the W/SW this afternoon, then will diminish to less than 10kt tonight. Barnes && .PREV DISCUSSION... ISSUED 312 AM CDT Fri May 9 2014 SHORT TERM...Today through Sunday Surface map at 06z indicated 999 mb low pressure near KMSP with a cold front trailing south through central IA and MO then down into central OK where a weaker 1007 mb low resided. South flow off the Gulf continued to pump in low to mid 60s dewpoints to central/SE IL. Aloft, W/V imagery showed a strong warm conveyor belt overhead which has produced rounds of thunderstorms mainly over eastern IL for the past few hours. Another shortwave just entering SW MO was sparking new thunderstorm development and this is expected to shift northeast across the area through mid-morning as the cold front moves into the western CWA. Short range models including HRRR and SPC 4km WRF suggest this activity will push east of the area by 18z while the cold front gradually tracks ESE across the CWA. It appears convective debris will clear out by early afternoon allowing upper 70s temps and mid 60s dewpoints to set up across the eastern CWA ahead of the front. This would suggest CAPE values around 2k J/kg with 40 kts 0-6km bulk shear overhead. Questions remain if new convection will fire along the front as low level convergence becomes less favorable. Any storms that develop could become severe with damaging wind gusts and hail given low wet-bulb zero heights near 9k ft. Radar simulations show most favored areas would be near or south of I-70 in a 21z-02z window. Any lingering activity will shift east of the region overnight as brief surface ridging moves overhead. This to provide dry and seasonably warm weather Saturday with highs in the upper 70s/lower 80s. The pattern turns active again Saturday night as warm advection precip ahead of the next Plains low develops in MO then lifts northeast across the CWA. Rising heights and another round of southerly flow ahead of this low should send another strong warm front north of the area Saturday night or Sunday with more associated precip chances. With the front now expected north by Sunday afternoon and with 850 mb temps rising into the mid teens have boosted highs to the low/mid 80s. Mixed signals if the warm sector will be dry/capped and as a result chance pops continue through Sunday night. LONG TERM...Monday through Thursday 00z model suite still has some major timing differences with a strong cold frontal passage Monday evening/night. EC continues to be most consistent and slowest solution. Depending on timing, severe weather will be a threat given dynamics with this system. Trends continue to show a major pattern change behind this cold front, as a deep upper level trough sets up over the central U.S. This will bring well below normal temps to the region as 850 mb readings are shown in the low single digits Tue-Thu, suggesting highs mainly in the 60s as lows in the 40s. With cold air and deep cyclonic flow overhead, diurnal heating may lead to scattered instability showers Tue-Thu. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1135 AM CDT FRI MAY 9 2014 .DISCUSSION... 1125 AM CDT WE CONTINUE TO MONITOR SCATTERED CONVECTION MAINLY ALONG AND EAST OF INTERSTATE 57 GOING INTO AFTERNOON WITH A SLIGHT RISK FOR SEVERE STORMS. NO MAJOR CHANGES MADE TO AFTERNOON TEMPERATURES OR STORM CHANCES...WITH SOME SUBTLE ADJUSTMENTS TO HOURLY TRENDS AND SPATIAL COVERAGE. MAIN SWATH OF MORNING PRECIPITATION ON THE LOW-LEVEL JET HAS SHIFTED EAST OF THE AREA. THE SURFACE COLD FRONT AND ASSOCIATED WESTERLY WIND SHIFT AND DRY ADVECTION IS LOCATED FROM NEAR WAUKEGAN TO JUST WEST OF PONTIAC AS OF 1115 AM. SOME SCATTERING OF CLOUDS IN ADVANCE OF THIS ALONG WITH CONTINUED WARM/MOIST ADVECTION AHEAD OF THE FRONT HAS LED TO DESTABILIZATION AHEAD OF THE FRONT WITHIN A MOISTURE-RICH WARM SECTOR. SCATTERED CONVECTION FROM THE SOUTH CHICAGO METRO TO KANKAKEE LOOKS SUPPORTED BY INCREASING LOW-LEVEL CONVERGENCE...WHICH SHOULD CONTINUE WITH THE BOUNDARY ADVANCING THIS AFTERNOON. AN UPSTREAM SHORT WAVE IN EASTERN MO AND BROADER FORCING FOR ASCENT WITH UPPER JET SUPPORT WOULD FAVOR INCREASING SHEAR AND A POTENTIAL INTENSIFICATION IN THE SCATTERED CONVECTION AFTER 1 PM OR SO...INCLUDING THE POSSIBILITY OF A FEW SEVERE STORMS IN THE SOUTHEAST FORECAST AREA CONCURRENT WITH THE SPC SLIGHT RISK. EARLIER CONVECTION THIS MORNING HAD PRODUCED SOME 40-52 MPH GUSTS ACROSS FAR NORTHWEST INDIANA AND ANY AFTERNOON CONVECTION COULD ALSO BE SPORADICALLY GUSTY. COOLING MID-LEVEL TEMPS AND STRONGER UPDRAFTS MAY SUPPORT SOME MARGINALLY SEVERE HAIL WITH THE STRONGEST STORMS AS WELL. MTF && .PREV DISCUSSION... 335 AM CDT MULTIPLE FORECAST CONCERNS THIS GO AROUND INCLUDING PRECIP CHANCES TODAY...CONVECTIVE POTENTIAL LATER IN THE WEEKEND...MAGNITUDE OF WARM UP AHEAD OF SYSTEM LATER THIS WEEKEND/EARLY NEXT WEEK...AND THEN TRANSITION TOWARD UNSEASONABLY COOL/UNSETTLED WEATHER NEXT WEEK. COLD FRONT IS APPROACHING THE MISSISSIPPI RIVER EARLY THIS MORNING WITH SOUTHERLY WINDS PUMPING WARM AND RATHER HUMID AIR NORTH INTO THE AREA. NUMEROUS SUBTLE SHORTWAVES CONTINUE MOVE NE ACROSS THE REGION RESULTING IN WAVES OF SHOWERS/T-STORMS. ONE WAVE IS MOVING EAST OF THE AREA AT 08Z...HOWEVER SHORT RANGE GUIDANCE HAS BEEN PRETTY INSISTENT THAT ANOTHER SHORTWAVE OVER MISSOURI WILL RESULT IN AN INCREASE IN PRECIP THE NEXT SEVERAL HOURS...MOVING INTO THE SOUTHEAST HALF TO TWO THIRDS OF THE CWA EARLY THIS MORNING. EXTENSIVE CIRRUS MAKES SEEING THIS WAVE ON GOES IMAGERY IMPOSSIBLE...BUT RECENT UPTICK IN SHOWERS OVER MISSOURI LENDS SOME CREDENCE TO THE MODEL GUIDANCE AND PLAN TO CARRY HIGH POPS FOR EARLY THIS MORNING. INSTABILITY IS FAIRLY WEAK SO NOT EXPECTING MUCH MORE THAN JUST AN ISOLATED THUNDERSTORM OR TWO WITH MAINLY JUST SHOWERS EARLY THIS MORNING. COLD FRONT WILL SWEEP ACROSS THE AREA LATER THIS MORNING INTO THE AFTERNOON USHERING IN A MUCH DRIER AIR MASS...THOUGH THE COLDER AIR LAGS SOME BEHIND THE FRONT. THE RESULT SHOULD BE BECOMING MOSTLY SUNNY WITH DRY WESTERLY WINDS LIKELY ALLOWING TEMPS TO HEAT UP NICELY WELL INTO THE 70S. THERE REMAINS A CHANCE THAT THE FRONT MAY NOT HAVE CLEARED OUR SE COUNTIES BY THE TIME CONVECTION REDEVELOPS THIS AFTERNOON...SO HAVE MAINTAINED SOME CHANCE POPS THIS AFTERNOON FAR SOUTHEAST CWA. ONCE FRONT MOVES EAST CONVECTIVE THREAT ENDS SE CWA THIS AFTERNOON WITH DRY AND MILD WEATHER EXPECTED TONIGHT INTO SATURDAY. WHILE PRESSURE GRADIENT WILL SUPPORT WEST WINDS SATURDAY AFTERNOON...AM CONCERNED THAT GRADIENT WILL BE WEAK ENOUGH TO ALLOW A WEAK AFTERNOON LAKE BREEZE TO DEVELOP AND CAUSING TEMPS NEAR THE LAKE TO FALL OFF SOME IN THE AFTERNOON. ANOTHER FAIRLY STRONG SHORTWAVE IS PROGGED TO PASS TO OUR NORTHWEST SATURDAY NIGHT WITH STRENGTHENING WARM AIR ADVECTION REGIME SETTING THE STAGE FOR SHOWERS/THUNDERSTORMS TO DEVELOP AGAIN SATURDAY NIGHT. WILL LIKELY SEE SOME BREAK IN THE CONVECTION SUNDAY...WITH MUCH OF THE DAY POTENTIALLY ENDING UP DRY AND WARM AS WE END UP BETWEEN SYSTEMS. SYNOPTIC WARM FRONT IS PROGGED TO BE NORTH OF THE AREA...BUT POTENTIAL EXISTS FOR NOCTURNAL CONVECTION SAT NIGHT TO AUGMENT THE FRONTAL POSITION AND THAT RAISES SOME UNCERTAINTIES WITH REGARDS TO TEMPS...ESPECIALLY ALONG THE LAKE BREEZE PRONE LAKE SIDE AREAS. NEXT STRONG SHORTWAVE IS EXPECTED TO EMERGE OUT ONTO THE CENTRAL PLAINS LATER SUNDAY WITH CYCLOGENESIS TO OUR WEST SUNDAY NIGHT LIKELY TO RESULT IN A SHARPENING SECONDARY WARM FRONT DEVELOPING TO OUR SOUTH. SHOWERS/THUNDERSTORMS LOOK TO BE A GOOD BET IN THE WAA REGIME SUNDAY NIGHT WITH SUFFICIENT SHEAR/INSTABILITY LIKELY TO BE PRESENT TO SUPPORT SOME SEVERE POTENTIAL SUNDAY NIGHT. WARM FRONT LIKELY TO MAKE IT NORTH OF THE CWA MONDAY...BUT TIMING DIFFERENCES DO EXISTS BETWEEN THE GFS AND ECMWF. LEANING TOWARD THE SLOWER TIMING OF THE ECMWF/GEM WHICH WOULD SUPPORT ANOTHER VERY WARM AND HUMID DAY MONDAY WITH MOSTLY DRY CONDITIONS BEFORE A STRONG COLD FRONT ARRIVES MONDAY NIGHT WITH INCREASING THREAT OF SHOWERS/THUNDERSTORMS. SYNOPTICALLY FAVORABLE PATTERN EXISTS FOR POTENTIALLY RESPECTABLE SEVERE WEATHER EPISODE MONDAY WITH TIMING OF THE SYSTEM DICTATING WHETHER THE GREATEST SEVERE THREAT WILL BE HERE OR TO OUR WEST. TOO SOON TO SAY FOR SURE...BUT MONDAY AND MONDAY NIGHT WARRANT CLOSE ATTENTION WITH LATER FORECASTS. BIG COLD UPPER LOW/TROUGH WILL SET UP SHOP OVER THE AREA TUESDAY THROUGH THURSDAY. VERY COLD AIR ALOFT WITH THIS UPPER LOW //-26C AT 500MB// SHOULD SUPPORT DIURNAL SCATTERED SHOWER AND POSSIBLY ISOLD T-STORM DEVELOPMENT. WHILE MUCH OF THE TIME WILL BE DRY TUES-THURS THERE COULD VERY WELL BE SOME SCTD (MAINLY DIURNAL) CONVECTION AROUND EACH DAY WHICH NECESSITATES MAINTAINING CHANCE POPS. UNSEASONABLY COOL TEMPERATURES ARE EXPECTED WITH HIGHS STRUGGLING TO REACH 60 BY WED AND THURSDAY. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * NEARBY SHRA TO MDW THROUGH 1730Z OR SO...WITH SCATTERED CONVECTION IN THE SOUTHERN TRACON AREA. * MVFR CIGS DISSIPATING BY EARLY THIS AFTERNOON. * GUSTY SOUTHWESTERLY WINDS THIS AFTERNOON. MTF/KJB //DISCUSSION...UPDATED 16Z... COLD FRONT IS MOVING EAST ACROSS NORTHERN IL ALTHOUGH SLOWING LATE THIS MORNING. SCATTERED SHRA/TSRA ARE DEVELOPING AHEAD OF THIS FROM JUST SOUTH OF MDW TO NEAR PNT. THESE ARE FAVORED TO REGENERATE THROUGH MID AFTERNOON BEFORE PUSHING EAST. THESE ARE HIGHLY LIKELY TO REMAIN SOUTH OF ORD BUT MDW IT MAY BE CLOSE FOR A FEW HOURS. //PREV DISCUSSION...UPDATED 12Z... THE THREAT FOR THUNDERSTORMS IS QUICKLY ENDING ACROSS THE AREA. HOWEVER...PERIODS OF SHOWERS WILL CONTINUE FOR A COUPLE MORE HOURS THIS MORNING...BEFORE ENDING. THE INCREASE IN LOWER LEVEL MOISTURE HAS ALSO LEAD TO SOME LOWER MVFR TO EVEN SOME IFR CIGS ACROSS PORTIONS OF THE AREA THIS MORNING. THESE LOWER CIGS ARE EXPECTED TO BE FAIRLY SHORT LIVED...WITH IMPROVEMENT TO VFR CONDITIONS EXPECTED BY MID TO LATE MORNING. THE WINDS WILL REMAIN GUSTY OUT OF THE SOUTH-SOUTHWEST...WITH GUSTS LIKELY UP AROUND 25 KT THROUGH MUCH OF THE DAY. A COOL FRONT WILL SHIFT ACROSS THE AREA BY LATE AFTERNOON/EARLY EVENING...WITH WINDS EXPECTED TO BECOME MORE WESTERLY AND ABATE BY EVENING. KJB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH THAT SHRA/TSRA WILL BE SOUTH OF MDW BY 19Z. * HIGH WITH WIND TRENDS. * MEDIUM WITH TIMING OF CIGS LIFTING TO VFR. MTF/KJB //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...SHRA/TSRA POSSIBLE. SUNDAY...PERIODS OF SHRA/TSRA POSSIBLE. MONDAY...PERIODS OF SHRA/TSRA POSSIBLE. TUESDAY THROUGH THURSDAY...CHANCE SHRA. KJB && .MARINE... 223 AM CDT LOW PRESSURE WILL SHIFT NORTHEASTWARD ACROSS THE LAKE SUPERIOR TODAY. THIS WILL RESULT IN ANOTHER DAY OF GUSTY SOUTH-SOUTHWESTERLY WINDS UP AROUND 25 KT ACROSS THE LAKE. A RIDGE OF HIGH PRESSURE WILL BUILD EASTWARD FROM THE MIDWEST TO LAKE MICHIGAN BY SATURDAY...WITH LIGHTER WINDS EXPECTED TO ACCOMPANY THIS RIDGE OF HIGH PRESSURE. ANOTHER AREA OF LOW PRESSURE IS FORECAST TO LIFT NORTHEASTWARD ACROSS THE UPPER MIDWEST EARLY NEXT WEEK...AND THIS LOOKS TO RESULT IN ANOTHER ACTIVE PERIOD OF WEATHER OVER THE A LAKE INTO THE MIDDLE OF NEXT WEEK. THIS COULD INCLUDE A PERIOD OF STRONGER SOUTHERLY WINDS AND MORE SHOWERS AND THUNDERSTORMS. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 PM FRIDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 926 AM CDT Fri May 9 2014 .DISCUSSION... ISSUED 926 AM CDT Fri May 9 2014 Overnight convection has lifted northeastward out of the area, leaving behind only a few scattered showers along/east of the I-57 corridor this morning. Cold front is currently approaching the Illinois River. Ahead of the boundary, southwesterly winds continue with 14z/9am temps in the upper 60s/lower 70s. Meanwhile behind the front, W/NW winds have dropped the temp into the upper 50s around Galesburg. Front will only make slow progress eastward today, with additional convection likely developing ahead of it during the afternoon hours. NAM and HRRR both suggest scattered thunderstorms will develop in the instability axis along/south of I-70 by mid to late afternoon. In the meantime, relatively stable airmass in the wake of the earlier convection should keep things quiet through early afternoon. Have updated the forecast to significantly reduce POPs this morning. Will only mention isolated to scattered showers east of the Illinois River through midday, then will increase POPs to likely for showers/thunder across the SE KILX CWA this afternoon. Barnes && .AVIATION... ISSUED 656 AM CDT Fri May 9 2014 The slow moving cold front will finally push across the terminal sites today. MVFR clouds between 1500-2500 FT will become more widespread during the first 3 to 5 hours of the TAFs, as low clouds develop near the front. A break in the rain should eventually work its way from west to east behind the front. The front should pass PIA to SPI by 16z, then reach CMI to DEC by 21z. The MVFR cigs should gradually give way to VFR cigs behind the front this afternoon. Storm redevelopment is expected later this afternoon ahead of the front, but the majority of those storms should be southeast of the TAF sites. DEC and CMI could get clipped as the line of storms develops after 20z, so a VCTS was left in the TAFS from 20z to 01z. Surface winds will remain out of a southerly direction at 12 to 17 kts early this morning with gusts to 25kt or higher at times in and near any thunderstorms. Winds will veer more into the southwest and then west this afternoon with speeds in the 15 to 20 kt range with gusts up to 30 kts possible, especially if we can get some sunshine to break through. VFR conditions are expected across the entire forecast area this evening thru 12z. Shimon && .PREV DISCUSSION... ISSUED 312 AM CDT Fri May 9 2014 SHORT TERM...Today through Sunday Surface map at 06z indicated 999 mb low pressure near KMSP with a cold front trailing south through central IA and MO then down into central OK where a weaker 1007 mb low resided. South flow off the Gulf continued to pump in low to mid 60s dewpoints to central/SE IL. Aloft, W/V imagery showed a strong warm conveyor belt overhead which has produced rounds of thunderstorms mainly over eastern IL for the past few hours. Another shortwave just entering SW MO was sparking new thunderstorm development and this is expected to shift northeast across the area through mid-morning as the cold front moves into the western CWA. Short range models including HRRR and SPC 4km WRF suggest this activity will push east of the area by 18z while the cold front gradually tracks ESE across the CWA. It appears convective debris will clear out by early afternoon allowing upper 70s temps and mid 60s dewpoints to set up across the eastern CWA ahead of the front. This would suggest CAPE values around 2k J/kg with 40 kts 0-6km bulk shear overhead. Questions remain if new convection will fire along the front as low level convergence becomes less favorable. Any storms that develop could become severe with damaging wind gusts and hail given low wet-bulb zero heights near 9k ft. Radar simulations show most favored areas would be near or south of I-70 in a 21z-02z window. Any lingering activity will shift east of the region overnight as brief surface ridging moves overhead. This to provide dry and seasonably warm weather Saturday with highs in the upper 70s/lower 80s. The pattern turns active again Saturday night as warm advection precip ahead of the next Plains low develops in MO then lifts northeast across the CWA. Rising heights and another round of southerly flow ahead of this low should send another strong warm front north of the area Saturday night or Sunday with more associated precip chances. With the front now expected north by Sunday afternoon and with 850 mb temps rising into the mid teens have boosted highs to the low/mid 80s. Mixed signals if the warm sector will be dry/capped and as a result chance pops continue through Sunday night. LONG TERM...Monday through Thursday 00z model suite still has some major timing differences with a strong cold frontal passage Monday evening/night. EC continues to be most consistent and slowest solution. Depending on timing, severe weather will be a threat given dynamics with this system. Trends continue to show a major pattern change behind this cold front, as a deep upper level trough sets up over the central U.S. This will bring well below normal temps to the region as 850 mb readings are shown in the low single digits Tue-Thu, suggesting highs mainly in the 60s as lows in the 40s. With cold air and deep cyclonic flow overhead, diurnal heating may lead to scattered instability showers Tue-Thu. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
136 PM EDT FRI MAY 9 2014 .SYNOPSIS... ISSUED AT 358 AM EDT FRI MAY 9 2014 A LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS THE UPPER GREAT LAKES TODAY AND ACROSS ONTARIO TONIGHT. A COLD FRONT TRAILING SOUTH FROM THE LOW WILL MOVE ACROSS OUR AREA THIS AFTERNOON AND TONIGHT. OCCASIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED AHEAD OF THE COLD FRONT TODAY WITH SCATTERED STORMS POSSIBLY LINGERING INTO THIS EVENING. HIGHS TODAY WILL BE IN THE MID 70S WITH LOWS TONIGHT RANGING FROM THE UPPER 40S OVER SOUTHWEST MICHIGAN AND NORTHWEST INDIANA... TO THE UPPER 50S OVER NORTHWEST OHIO. && .UPDATE... ISSUED AT 1020 AM EDT FRI MAY 9 2014 LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS CURRENTLY APPROACHING THE AREA...ASSOCIATED WITH A WEAK VORT MAX JUST AHEAD OF THE MAIN SURFACE COLD FRONT. SPC/RAP MESOANALYSIS SHOWS ALMOST NO INSTABILITY ACROSS NORTHERN INDIANA...EXPLAINING THE LACK OF RECENT LIGHTNING. EXPECT THIS WILL CONTINUE TO BE THE CASE THROUGH THE MORNING WITH OVERCAST SKIES AND SOME LIGHT SHOWERS CONTINUING AHEAD OF THE MAIN LINE. LATEST RAP13 AND HRRR SHOW ONLY A FEW HUNDRED J/KG OF SBCAPE THROUGH THE EARLY AFTERNOON. SEVERE WEATHER POTENTIAL WITH THIS ACTIVITY IS VERY LOW BUT A FEW WIND GUSTS AROUND 40MPH AND SOME SMALL HAIL WILL BE POSSIBLE GIVEN 850MB WINDS OF 40-50 KNOTS AND RELATIVELY COLD TEMPS ALOFT/LOW FREEZING LEVELS. HI-RES GUIDANCE INDICATES THE POTENTIAL FOR A SLIGHT RECOVERY IN OUR WEST AND SOUTHWEST COUNTIES LATER THIS AFTERNOON WITH MIDLEVEL DRY AIR BEHIND THE INITIAL SHORTWAVE POSSIBLY ALLOWING FOR A FEW PEAKS OF SUN...SIMILAR TO CURRENT VIS IMAGERY OVER ILLINOIS. WINDOW OF OPPORTUNITY FOR SEVERE WEATHER WILL BE SMALL THOUGH AND FORECAST SBCAPES ARE STILL ONLY AROUND 1000 J/KG...LIMITING UPDRAFT STRENGTH. WILL BE DIFFICULT TO ADEQUATELY DESTABILIZE AFTER THIS MORNING RAIN. ONCE AGAIN...STRAIGHT LINE WINDS AND SMALL HAIL WOULD BE THE MAIN THREATS WITH THE BEST CHANCES PROBABLY IN THE 4-8PM TIMEFRAME BUT THE SEVERE WEATHER THREAT REMAINS HIGHLY CONDITIONAL AT THIS POINT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 348 AM EDT FRI MAY 9 2014 UPR TROF OVER THE PLAINS WILL LIFT NE ACROSS THE GRTLKS AND DEAMPLIFY TODAY-TNGT. LEAD SHRTWV WILL MOVE ACROSS OUR AREA THIS MORNING ACCOMPANIED BY A LOW LEVEL THETA-E PLUME/WK INSTABILITY RESULTING IN WIDESPREAD SHOWERS/TSTMS. MID LEVELS SHOULD DRY OUT IN WAKE OF THIS LEAD WAVE THIS AFTN... ALLOWING FOR DECREASING CLOUDINESS AND DESTABILIZATION AS LOW LEVELS REMAIN MOIST AHEAD OF SFC CDFNT AND APCHG MAIN TROF. NAM SUGGESTS INSTABILITY WILL REACH AROUND 1500J/KG OVER NRN INDIANA AND SRN MI THIS AFTN WITH 0-6KM MAINLY UNIDIRECTIONAL SHEAR INCREASING TO AROUND 50KT. THOUGH FORCING APPEARS FAIRLY WK THIS AFTN AS MOISTURE CONVERGENCE ALONG CDFNT MINIMAL AND UPR TROF DEAMPLIFING... MODERATE INSTABILITY... STRONG SHEAR... AND DRY MID LEVELS SUGGEST A POTENTIAL FOR SVR TSTMS WITH DAMAGING WINDS AND LARGE HAIL... MAINLY ACROSS NRN INDIANA IF DESTABILIZATION OCCURS AS FCST AND FORCING IS SUFFICIENT FOR CONVECTION TO DEVELOP DURING PEAK HEATING. CURRENT TEMPS NEAR PREVIOUS FCST HIGHS FOR TODAY... BUT TEMPS SHOULD RISE LITTLE THIS MORNING WITH WIDESPREAD SHOWERS MOVG THROUGH AND CONSIDERABLY COOLER ALOFT THAN YDAY... SO EXPECT HIGHS TODAY GENERALLY IN THE M70S. WKNG CDFNT WILL MOVE ACROSS THE AREA TONIGHT PRBLY ACCOMPANIED BY SCT SHOWERS/TSTMS THIS EVE... WITH CONVECTION DIMINISHING AND MOVG EAST OVERNIGHT. WK HIGH PRESSURE WILL BUILD INTO THE AREA OVERNIGHT ALLOWING FOR CLEARING SKIES. SOME PATCHY FOG PSBL ACROSS WRN PORTIONS OF THE AREA BUT HELD OFF ADDING AT THIS JUNCTURE. TEMPS WILL BE CONSIDERABLY COOLER WITH LOWS RANGING FROM THE U40S NW TO THE U50S SE. && .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 348 AM EDT FRI MAY 9 2014 LARGE SCALE SUBSIDENCE/DRYING WILL SUPPORT A DRY/COOLER SATURDAY AS A WEAK AREA OF HIGH PRESSURE BUILDS IN BEHIND FRIDAY NIGHT`S FRONTAL BOUNDARY. STRENGTHENING SOUTHWEST FLOW IN ADVANCE OF LONGWAVE TROUGH AMPLIFICATION INTO THE WESTERN US SUNDAY AND HIGH PLAINS EARLY NEXT WEEK WILL ALLOW GULF MOISTURE TO ADVECT WELL NORTH INTO THE GREAT LAKES REGION DURING THIS TIME. LOW LEVEL THETA-E GRADIENT/WARM FRONT IN ADVANCE OF THIS SYSTEM ON LLJ NOSE MAY BRING SOME MAINLY ELEVATED CONVECTION TO THE AREA (FROM SW TO NE) LATER SATURDAY NIGHT THROUGH SUNDAY NIGHT...WITH POPS KEPT IN THE LOW/MID CHC RANGE GIVEN THE ABSENCE OF ANY WELL-DEFINED MID/UPPER LEVEL FORCING. 00Z GUIDANCE CONTINUED THE TREND TOWARD THE SLOWER ECMWF SOLUTION REGARDING EASTWARD PROGRESSION OF THE UPPER TROUGH NEXT WEEK AS SYSTEM EVENTUALLY PHASES WITH A CANADIAN PRAIRIES UPPER LOW. THIS MAY LEAVE THE IWX CWA COMPLETELY IN THE WARM SECTOR BY MONDAY-MONDAY NIGHT...ALTHOUGH CANNOT RULE OUT PCPN GIVEN MOIST AIRMASS/WEAK CAPPING AND POTENTIAL FOR WEAK CONVECTIVELY ENHANCED/INDUCED SHORTWAVES TO LIFT NORTHEAST INTO THE AREA WITHIN SOUTHWEST FLOW. SHOWER/STORM CHANCES INCREASE AGAIN BY TUESDAY-TUESDAY NIGHT AS HEIGHT FALLS OVERSPREAD PRE-FRONTAL TROUGH OR COLD FRONT. HELD CLOSE TO PREV FCST (MID CHC POPS) BUT DID TREND TEMPS UP CLOSER TO WARMER ECM/MEX MOS AND HPC GUIDANCE MONDAY-TUESDAY. COOLER WX RETURNS WEDNESDAY INTO THURSDAY IN WAKE OF FRONT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 136 PM EDT FRI MAY 9 2014 SURFACE COLD FRONT EXTENDING FROM LOW PRESSURE OVER THE NORTHERN GREAT LAKES IS SLOWLY APPROACHING THE AREA. WEAK LOW LEVEL CONVERGENCE IN A SUFFICIENTLY MOIST ENVIRONMENT IS SUPPORTING A FEW SHOWERS ACROSS THE AREA. INSTABILITY HAS BEEN LIMITED BY MORNING PRECIPITATION AND MOSTLY CLOUDY SKIES THOUGH. THUNDERSTORMS WILL THEREFORE REMAIN ISOLATED THROUGH THE EVENING. THERE IS STILL A CHANCE FOR A THUNDERSTORMS TO IMPACT EITHER KSBN OR KFWA BUT THE PROBABILITY IS TOO LOW AND TIMING IS TOO UNCERTAIN FOR INCLUSION IN THE TAF. PERIODS OF MVFR CEILINGS WILL BE POSSIBLE UNTIL FRONT CLEARS THE AREA LATER TONIGHT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LMZ043- 046. && $$ UPDATE...AGD SYNOPSIS...JT SHORT TERM...JT LONG TERM...STEINWEDEL AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
401 PM CDT Fri May 9 2014 ...Updated Longterm section... .SHORT TERM...(This evening through Saturday) ISSUED AT 313 PM CDT FRI MAY 9 2014 The upper level jet is progged to continue moving east this afternoon with western Kansas coming under the left exit region of upper jet this evening. Model soundings from the NAM and RUC13 show fairly deep mixing with some small elevated CAPE developing along the Colorado border by late this afternoon. The last few runs of the HRRR have been consistent in showing isolated showers developing along the Colorado border and moving into west central and southwest Kansas for a few hours this evening. Will add this to the grids for this evening. As the weak shortwave moves over late tonight, another weak surge of high pressure will push into southwest Kansas late tonight and early Saturday. Overnight lows will drop into the mid 40s over west central Kansas where dewpoints will be lower and winds could go light for a few hours around sunrise. Low temperatures in south central Kansas may only drop into the mid 50s where dewpoints are higher. During the day Saturday, mid level flow over the central Plains gradually becomes southwesterly with time as an upper level shortwave trough digs into the western states. This will result in surface cyclogenesis over southeast Colorado during the afternoon. Areas of southwest Kansas along the Oklahoma border should see high temperatures rising into the upper 80s to near 90 degrees with southerly winds increasing during the day. This could result in critical fire weather conditions over far southwest Kansas in the afternoon. .LONG TERM...(Saturday night through Friday) ISSUED AT 349 PM CDT FRI MAY 9 2014 The first issue during this period will be Saturday night. Rich gulf moisture is not too far southeast, meaning it`s as close as extreme southeast Oklahoma and north Texas. With the vigorous jet and upper level anomaly digging into the Rockies, the surface response will be rapidly falling pressure in the lee of the Rockies. The surface low should deepen in southeast Colorado. Boundary layer winds will become east to southeast and the aforementioned rich moisture will begin stream northwest towards my forecast area. Warm frontogenesis will take place and this will advance rapidly north by Saturday night. I see a small opportunity of elevated and nocturnal convection developing along the nose of the moisture surge across my far southeast area after dark Saturday night. Confidence is not high though. Sunday will be the "warm" day in advance of a strong surge of cold air that will be sweeping into the plains as the digging system into the Rockies lifts out into the plains. There should be a rather tight gradient of temperatures across my area and will adjust the grids accordingly. With the rich gulf moisture, strong uvv and surface convergence along the front the chance for thunderstorms will be high late Sunday and Sunday evening. Behind the front there should be continued lift and with strong cold air advection there should be low stratus and at least drizzle, if not light rain. Monday should be a rather raw day with clouds, blustery winds and some precipitation. My forecast highs may be a little optimistic but the trend is to definitely cooler temperatures. Beyond Monday, the flow will be northwest flow aloft with perhaps another minor wave sliding southeast which might promote showers about mid week. Overall temperatures will be below normal seasonal normals. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 1220 PM CDT FRI MAY 9 2014 VFR conditions will prevail through this TAF period as high level moisture will bring a scattered to broken cirrus clouds over the central High Plains this afternoon and tonight. Southerly winds at 10 to 15 knots this afternoon will diminish tonight and become light and variable. && .PRELIMINARY POINT TEMPS/POPS... DDC 48 85 57 81 / 0 0 10 20 GCK 46 83 51 77 / 10 0 10 10 EHA 47 88 47 78 / 10 0 0 10 LBL 48 89 52 82 / 10 0 10 10 HYS 47 82 56 77 / 0 0 10 10 P28 54 89 68 91 / 0 10 20 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gerard LONG TERM...Hutton AVIATION...Gerard
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
314 PM CDT Fri May 9 2014 ...Updated synopsis and short term discussion... .SYNOPSIS... ISSUED AT 313 PM CDT FRI MAY 9 2014 This mornings upper air analysis showed a shortwave trough moving east through the upper Midwest while another shortwave was moving into the Big Bend region of Texas with more subtle shortwave energy moving through the central Rockies. Higher up, a 300 millibar jet was nosing into the Intermountain West. At the surface, a weak low pressure trough extended south along the eastern slopes of the Rockies. && .SHORT TERM...(This evening through Saturday) ISSUED AT 313 PM CDT FRI MAY 9 2014 The upper level jet is progged to continue moving east this afternoon with western Kansas coming under the left exit region of upper jet this evening. Model soundings from the NAM and RUC13 show fairly deep mixing with some small elevated CAPE developing along the Colorado border by late this afternoon. The last few runs of the HRRR have been consistent in showing isolated showers developing along the Colorado border and moving into west central and southwest Kansas for a few hours this evening. Will add this to the grids for this evening. As the weak shortwave moves over late tonight, another weak surge of high pressure will push into southwest Kansas late tonight and early Saturday. Overnight lows will drop into the mid 40s over west central Kansas where dewpoints will be lower and winds could go light for a few hours around sunrise. Low temperatures in south central Kansas may only drop into the mid 50s where dewpoints are higher. During the day Saturday, mid level flow over the central Plains gradually becomes southwesterly with time as an upper level shortwave trough digs into the western states. This will result in surface cyclogenesis over southeast Colorado during the afternoon. Areas of southwest Kansas along the Oklahoma border should see high temperatures rising into the upper 80s to near 90 degrees with southerly winds increasing during the day. This could result in critical fire weather conditions over far southwest Kansas in the afternoon. .LONG TERM...(Saturday through Thursday) ISSUED AT 221 AM CDT FRI MAY 9 2014 Models this morning remain in decent agreement with moving an upper low, which was located off the coast of British Columbia near 140W at 00z Friday, into the four corners region by early Sunday. As this next system moves into the southwest United States early this weekend a trough of low pressure at the surface will deepen along the lee of the Rockies and temperatures in the 850mb to 700mb layer will warm. Given the mixing potential suggested by the latest model soundings, and the 850mb to 700mb temperatures at 00z Sunday the previous forecast still looks on track with highs in the 80s despite a cold front moving into southwest Kansas late Saturday. Precipitation chance still appear to be more favorable north of the interstate 70 corridor given the warm mid level temperatures forecast over southwestern Kansas Saturday afternoon, frontal boundary location, where the better forcing from the 850mb warm air advection, and upper level jet dynamics will be located. Precipitation chances will increase across western Kansas late this weekend as the upper level low/trough approaches the Central High Plains and the elevated mix layer begins to move east. By Sunday night 850mb to 700mb moisture and frontogenesis will begin to improve across far western Kansas/eastern Colorado as difluent flow improves across eastern Colorado and western Kansas near the nose of an upper level jet that will be ejecting from the base of the upper level trough. As precipitation chances improves to our west/northwest...scattered late day convection will be possible across south central Kansas. This area will be along and east of a dryline where afternoon CAPE values increase to greater than 2000 j/kg. 0-6km shear and instability suggests severe thunderstorms will be possible in this area late day. Will therefore include a mention in the HWO concerning severe potential in south central Kansas late Sunday. Afternoon thunderstorms in south central Kansas are forecast to move east during the evening and the area of thunderstorms associated with the mid level baroclinic zone begins to spread into north central and portion of southwest Kansas. Will continue to favor the higher chances of precipitation Sunday night as this mid level baroclinic zone spreads east across the western Kansas. Precipitation chances will taper off as the mid level baroclinic zone moves east into central Kansas late Monday, however a few isolated/widely scattered showers/thunderstorms still looks possible through late day across north central and portions of west central Kansas given the mid level lapse rates under the 500mb thermal trough. Based on expected cloud cover and 850mb temperature trends will stay close to the previous forecast for highs on Monday which were slightly cooler than the latest guidance. Monday night into Tuesday as surface high will cross western Kansas. Based on decreasing wind and clear skies will continue to favor temperatures cooler guidance for lows Monday night. Tuesday will be warmer than Monday based on the 850mb temperatures at 00z Wednesday. Highs on Tuesday will are currently expected to range from the mid 60s to around 70 degrees. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 1220 PM CDT FRI MAY 9 2014 VFR conditions will prevail through this TAF period as high level moisture will bring a scattered to broken cirrus clouds over the central High Plains this afternoon and tonight. Southerly winds at 10 to 15 knots this afternoon will diminish tonight and become light and variable. && .PRELIMINARY POINT TEMPS/POPS... DDC 48 82 55 81 / 0 0 10 10 GCK 47 81 50 72 / 0 0 10 10 EHA 50 85 50 77 / 0 0 0 10 LBL 48 86 52 80 / 0 0 10 10 HYS 48 80 52 69 / 0 0 10 20 P28 53 86 61 88 / 0 10 10 30 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Gerard SHORT TERM...Gerard LONG TERM...Burgert AVIATION...Gerard
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1116 AM MDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 258 AM MDT FRI MAY 9 2014 EARLY MORNING WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS CONFLUENT FLOW ENTERING ROCKIES OVER PLAINS ON BACK SIDE OF DEPARTING TROUGH...WITH WEAK SHORTWAVE ENERGY UPSTREAM NEAR DIFLUENT FLOW OVER GREAT BASIN. AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER OUR CWA WITH STATIONARY FRONT ALONG FRONT RANGING AND COLD FRONT OVER OK/TX PANHANDLES. RADAR SHOWS SOME VIRGA AND VERY LIGHT SPRINKLES LINGERING AS A SHORTWAVE IS EJECTING ACROSS THE SOUTHERLY PLAINS. WITH SUBSIDENCE BUILDING IN FROM THE NORTH THIS ACTIVITY LIKELY WONT LAST LONG. TEMPS HAVE DROPPED INTO THE MID 30S ACROSS THE WEST...AND WE COULD SEE A FEW LOW TEMPS AROUND FREEZING BY SUNRISE. A WEAK SHORTWAVE TROUGH WILL PASS NORTH OF THE CWA THIS AFTERNOON AND EVENING AND MAY COMBINE WITH AFTERNOON/EVENING INSTABILITY TO PRODUCE A FEW THUNDERSTORMS OVER NE COLORADO. VERY DRY LOW LEVELS WOULD LIMIT PRECIP REACHING THE SURFACE. DECIDED TO KEEP SMALL AREA OF OUR NW CWA WITH ISO THUNDER AROUND 00Z AND OTHERWISE LIMITED PRECIP MENTION TO SPRINKLES. SEASONAL TEMPS SHOULD RETURN AS SOUTHERLY FLOW REDEVELOPS TODAY...WITH HIGHS IN THE 70S AND OVERNIGHT LOWS TONIGHT IN THE LOW-MID 40S (MAYBE A FEW SPOTS A LITTLE COLDER WEST). SATURDAY-SUNDAY NIGHT...COMPLICATED FORECAST AS THE NEXT STRONG UPPER TROUGH IS EXPECTED TO IMPACT THE CENTRAL ROCKIES AND PLAINS. SOUTHWESTERLY FLOW DEVELOPS ACROSS THE ROCKIES WHICH WOULD INITIALLY LIMIT ANY SHOWER/THUNDERSTORM CHANCES TO THE NW SATURDAY. HOWEVER BY SATURDAY NIGHT THE MAIN TROUGH BEGINS TO SLIDE EAST ALLOWING GOOD MOISTURE AND LIFT OT BUILD OVER THE CWA. BEST PRECIP CHANCES ACROSS THE CWA STILL LOOKS TO BE ON SUN/SUN NIGHT AND MODELS SHOW REASONABLE AGREEMENT ON MEASURABLE PRECIP SO I BUMP POPS INTO 60-70 RANGE FOR THOSE PERIODS. A LITTLE LESS CONFIDENT ON AREA OF BEST PRECIP...THOUGH PARTS OF THE REGION (ESPECIALLY WEST) COULD SEE DECENT LIQUID ACCUMULATION WITH THIS EVENT (0.15-0.75"). REGARDING WEATHER TYPE...VERY LIMITED INSTABILITY THROUGH MOST OF THE EVENT...SO ONLY KEPT THUNDER MENTION SATURDAY AFTERNOON/EVENING. TEMP PROFILES AND WBZ HEIGHTS WOULD INDICATE A RAIN/SNOW MIX OR A COMPLETE CHANGEOVER ACROSS THE WESTERN HALF OF THE CWA SUNDAY NIGHT. WARM GROUND TEMPS MAY LIMIT ANY SNOW ACCUMULATION (ASSUMING LIGHTER RATES). IN ADDITION TO WARM GROUND TEMPS...CONFIDENCE OF CHANGEOVER TIMING IS LOW SO I LEFT ACCUMULATION MENTION OUT OF FORECAST. I DID INCLUDE RAIN/SNOW MENTION AND A BRIEF PERIOD OF ALL SNOW AROUND SUNRISE EARLY MONDAY MORNING. WILL NEED TO WATCH HOW THIS SYSTEM EVOLVES TO ZERO IN ON THESE DETAILS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 258 AM MDT FRI MAY 9 2014 MODELS ARE STILL IN DISAGREEMENT WITH THE POSITION AND PROGRESSION OF THE UPPER LEVEL TROUGH IN THE EXTENDED. GFS STILL MOVES IT FURTHER EAST MORE QUICKLY THAN THE ECMWF. HOWEVER...THE TROUGH WILL CONTINUE TO INFLUENCE THE CWA ON MONDAY. TEMPERATURES MONDAY MORNING APPEAR COLD ENOUGH FOR LIGHT SNOW TO CONTINUE OVER EASTERN COLORADO WITH A RAIN SNOW MIX IN NORTHWEST KANSAS IN COUNTIES BORDERING EASTERN COLORADO. TEMPERATURES SHOULD WARM ENOUGH BY 15Z FOR ALL PRECIPITATION TO BE RAIN...WITH THE CHANCE FOR RAIN CONTINUING MONDAY AFTERNOON. MONDAY WILL REMAIN BREEZY AS THE TIGHT PRESSURE GRADIENT STAYS OVER THE CWA UNTIL MONDAY NIGHT WHEN IT RELAXES AND SURFACE HIGH PRESSURE SETTLES IN OVER COLORADO. TUESDAY THROUGH WEDNESDAY SHOULD REMAIN DRY AS THE UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES BECOMES MORE INFLUENTIAL IN THE HIGH PLAINS. BY THURSDAY...A SHORTWAVE TROUGH WILL ROTATE AROUND THE UPPER TROUGH OVER THE GREAT LAKES REGION SENDING A WEAK COLD FRONT THROUGH THE CWA. SHOWERS AND THUNDERSTORMS COULD DEVELOP AHEAD OF THE FRONT...SINCE THE GFS DOES HAVE A FEW HUNDRED J/KG OF CAPE OVER EASTERN COLORADO. AS PREVIOUSLY MENTIONED...THE MODELS ARE HAVING A HARD TIME COMING TO A CONSENSUS FOR ANY DAY IN THE EXTENDED...SO AM TRYING TO GET AWAY FROM GETTING TOO DETAILED FOR THUNDERSTORM POTENTIAL IN DAY 7. WELL BELOW AVERAGE TEMPERATURES CAN BE EXPECTED TO START OFF THE EXTENDED PERIOD WITH HIGHS ON MONDAY IN THE LOW TO UPPER 50S. LOWS MONDAY NIGHT WILL BE IN THE LOW 30S TO LOW 40S WITH HIGHS ON TUESDAY IN THE LOW TO MID 60S. SLIGHTLY BELOW TO NEAR NORMAL TEMPERATURES WILL TAKE OVER THROUGH THE REST OF THE EXTENDED WITH HIGHS IN THE MID 60S TO LOW 70S ON WEDNESDAY AND THURSDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1112 AM MDT FRI MAY 9 2014 VFR EXPECTED THROUGH THE PERIOD AT BOTH KGLD AND KMCK. A FEW SCATTERED HIGH BASED CU WILL FORM THROUGH THE AFTERNOON AS CONVECTIVE TEMPERATURES ARE REACHED. HOWEVER SUB CLOUD LAYERS ARE BONE DRY AND END RESULT WILL ONLY BE VIRGA OR A FEW SPRINKLES...DISSIPATING AFTER SUNSET. OTHERWISE...A COLD FRONTAL PASSAGE AROUND SUNRISE SATURDAY MORNING WILL SHIFT SURFACE WINDS TO NORTHWEST AND THEY WILL BE BREEZY THROUGH SATURDAY MORNING. && .FIRE WEATHER... ISSUED AT 243 AM MDT FRI MAY 9 2014 WITH WARMER TEMPS AND LOWER TD MIXING TO THE SURFACE WE COULD SEE RH VALUES WITHIN RFW CRITERIA ACROSS THE SOUTHERN PART OF OUR FORECAST AREA BOTH TODAY AND SATURDAY AFTERNOON/EARLY EVENING PERIODS. TODAY WINDS WILL BE WELL BELOW CRITERIA WITH WEAK GRADIENT IN PLACE...SO NO RFW PRODUCT ANTICIPATED. SW PRESSURE GRADIENT BEGINS TO INCREASE SATURDAY AHEAD OF DEEPENING UPPER LOW...THOUGH EVOLUTION OF SURFACE LOW AND FRONT POSITION WILL BE CRITICAL FOR WHERE WINDS WITHIN RFW CRITERIA WILL CROSS WITH LOW RH. NOT ENOUGH CONFIDENCE AT THIS POINT TO ISSUE A FIRE WEATHER WATCH FOR SATURDAY...BUT WE WILL PROBABLY NEED TO MONITOR. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...ALW AVIATION...024 FIRE WEATHER...DR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
514 PM EDT Fri May 9 2014 ...Updated Aviation Discussion... .SHORT TERM (Now through Saturday Night)... Issued at 305 PM EDT Fri May 9 2014 In the near term, rainfall from this morning continues to move NE but is still hanging in there over east-central KY. The rain will exit our forecast area in the next 1-2 hrs. Otherwise, conditions are dry with ample cloud cover over the rest of the region, with some cumulus clouds now starting to emerge with modest diurnal warming and decent low-level moisture. Nevertheless, the atmosphere remains relatively stable at this time, as evidenced by current SPC mesoanalysis. Thus, expect mainly rain free weather for the next few hours over central KY and south-central IN as temperatures top out thru the 70s to around 80 west. Meanwhile, convection continues to slowly develop along and ahead of a low-level frontal boundary and confluent zone from southwest IL into south-central MO. Latest SPC mesoanalysis shows an axis of -4 to -6 surface-based LI values and around 1000 J/kg CAPE in this axis. All short-range models and the latest HRRR and SPC SREF suggest this convection will continue to develop and expand E-NE late this afternoon and evening. Model soundings in our area show lapse rates increasing late this afternoon and evening, especially aloft resulting in a more conducive environment in time to develop and maintain convection within. As a result, will ramp up POPs this evening, first over south-central IN and northwest KY, then eastward later tonight. The best chances for severe storms are to our west in the area of the current SPC severe thunderstorm watch, enhanced by good instability and deep-layer speed shear (with a strong upper jet advancing eastward). As the storms move east later tonight, they may have a tendency to become slightly elevated with modest nocturnal cooling over our area. Nevertheless, the boundary layer may stay adequately mixed to allow some downward momentum transport from the strongest cells to produce isolated strong or damaging winds, mainly along and west of the I-65 corridor. After the storms move through, can`t totally rule out additional scattered showers and isolated thunderstorms well after midnight and into Saturday morning as a mid-level shortwave approaches. During the day Saturday, the shortwave will pass through our area. This could continue the chance for scattered showers and storms over eastern and southern forecast area in the morning, but should effectively clear things out later in the day. As a result, much of the afternoon should be precipitation free with temperatures rising through the 70s. If enough sunshine occurs in the afternoon, could see around 80 or lower 80s in western half of forecast area. Air mass will begin to destabilize again Saturday afternoon in the wake of the morning showers, but forcing should be quite limited in the wake of the morning shortwave. Therefore, expect only isolated cell redevelopment by late afternoon mainly over western and northern areas of forecast area. This activity could become a little more prevalent, especially northern half of forecast area, Saturday night if a model weak signal of another approaching shortwave proves correct. .LONG TERM (Sunday through Friday)... Issued at 250 PM EDT Fri May 9 2014 The long term period will be fairly active with multiple chances for showers and thunderstorms. In addition, a big shift in the upper air pattern will bring much cooler temperatures by the end of the next work week. For Sunday through Monday ridging will be building aloft. At the surface, high pressure will be centered off the east coast. Southerly winds on the back side of this high pressure will usher in warm and moist air to the lower Ohio Valley. Temperatures on Sunday will warm into the lower to mid 80s. Soundings show surface based instability developing during the afternoon and little to no cap across the area. However, with the lack of a trigger, storms look to remain scattered in nature and should mostly dissipate during the evening hours. For Monday soundings show more of a cap in place, so rain chances look to be less than Sunday. However, isolated to scattered showers and storms will still be possible. Highs will be in the mid 80s. A cold front will approach and move through the area during the Tuesday through Wednesday time frame. There is still quite a bit of discrepancy in the timing of this frontal passage. Thus, have gone with pops over a wider time frame than is expected with the frontal passage to account for uncertainty. For now, it looks like Tuesday/Tuesday night will be the best chance for showers and storms. However, if slower solutions pan out, chances will linger into Wednesday. The timing issue with the front will also have quite an impact on temperatures mid week as a trough will move in behind this system. This will usher in cooler air for the end of the week. Highs Thursday and Friday will be in the lower to mid 60s with lows in the upper 40s. There may be a slight chance of rain toward the end of the long term as a weak disturbance moves through the flow aloft, but timing with these is usually fairly questionable this far out. && .AVIATION (21Z TAF Update)... Issued at 515 PM EDT Fri May 9 2014 Updated SDF TAF to better time t-storms through the TAF site. 23Z-1Z would be the best time for SDF to see moderate t-storms causing flight restrictions. Instability and dynamics are lacking this far east from the current convective line near the IL/IN border so storms are expected to decrease in intensity as they move closer to the I-65 corridor. Issued at 130 PM EDT Fri May 9 2014 Area of showers and isolated thunderstorms continues to progress east over east-central KY at this time. Conditions are currently VFR at LEX, but could briefly go MVFR around 1800-1830z with an area of moderate-to-heavy rain approaching. Otherwise, conditions will remain VFR at LEX, as well as SDF and BWG this afternoon in the wake of the rain. Winds this afternoon will remain gusty up to 20 kts from the S-SW then stay more steady from 5-12 kts tonight. Then, attention turns to developing thunderstorms over MO near a frontal boundary. Air mass ahead of these storms will destabilize resulting in additional development this afternoon. Scattered to numerous storms could then move into central KY, including SDF and BWG this evening in the 00-06z time frame. With this in mind, have indicated a TEMPO group for a few hours for thunderstorms and MVFR conditions to try to narrow down the best expected time of occurrence. The expected convection should also reach LEX later tonight, although probably in a weakening state. Thereafter, coverage should wane, but can`t rule out isolated or scattered showers and storms the rest of the night, so have kept VCTS and VCSH in at all TAFs. On Saturday, could be isolated or scattered showers around in the morning, with scattered diurnal storms again possible in vicinity of SDF from 18-00z. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........TWF Long Term.........EER Aviation..........TWF/AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
315 PM EDT Fri May 9 2014 .SHORT TERM (Now through Saturday Night)... Issued at 305 PM EDT Fri May 9 2014 In the near term, rainfall from this morning continues to move NE but is still hanging in there over east-central KY. The rain will exit our forecast area in the next 1-2 hrs. Otherwise, conditions are dry with ample cloud cover over the rest of the region, with some cumulus clouds now starting to emerge with modest diurnal warming and decent low-level moisture. Nevertheless, the atmosphere remains relatively stable at this time, as evidenced by current SPC mesoanalysis. Thus, expect mainly rain free weather for the next few hours over central KY and south-central IN as temperatures top out thru the 70s to around 80 west. Meanwhile, convection continues to slowly develop along and ahead of a low-level frontal boundary and confluent zone from southwest IL into south-central MO. Latest SPC mesoanalysis shows an axis of -4 to -6 surface-based LI values and around 1000 J/kg CAPE in this axis. All short-range models and the latest HRRR and SPC SREF suggest this convection will continue to develop and expand E-NE late this afternoon and evening. Model soundings in our area show lapse rates increasing late this afternoon and evening, especially aloft resulting in a more conducive environment in time to develop and maintain convection within. As a result, will ramp up POPs this evening, first over south-central IN and northwest KY, then eastward later tonight. The best chances for severe storms are to our west in the area of the current SPC severe thunderstorm watch, enhanced by good instability and deep-layer speed shear (with a strong upper jet advancing eastward). As the storms move east later tonight, they may have a tendency to become slightly elevated with modest nocturnal cooling over our area. Nevertheless, the boundary layer may stay adequately mixed to allow some downward momentum transport from the strongest cells to produce isolated strong or damaging winds, mainly along and west of the I-65 corridor. After the storms move through, can`t totally rule out additional scattered showers and isolated thunderstorms well after midnight and into Saturday morning as a mid-level shortwave approaches. During the day Saturday, the shortwave will pass through our area. This could continue the chance for scattered showers and storms over eastern and southern forecast area in the morning, but should effectively clear things out later in the day. As a result, much of the afternoon should be precipitation free with temperatures rising through the 70s. If enough sunshine occurs in the afternoon, could see around 80 or lower 80s in western half of forecast area. Air mass will begin to destabilize again Saturday afternoon in the wake of the morning showers, but forcing should be quite limited in the wake of the morning shortwave. Therefore, expect only isolated cell redevelopment by late afternoon mainly over western and northern areas of forecast area. This activity could become a little more prevalent, especially northern half of forecast area, Saturday night if a model weak signal of another approaching shortwave proves correct. .LONG TERM (Sunday through Friday)... Issued at 250 PM EDT Fri May 9 2014 The long term period will be fairly active with multiple chances for showers and thunderstorms. In addition, a big shift in the upper air pattern will bring much cooler temperatures by the end of the next work week. For Sunday through Monday ridging will be building aloft. At the surface, high pressure will be centered off the east coast. Southerly winds on the back side of this high pressure will usher in warm and moist air to the lower Ohio Valley. Temperatures on Sunday will warm into the lower to mid 80s. Soundings show surface based instability developing during the afternoon and little to no cap across the area. However, with the lack of a trigger, storms look to remain scattered in nature and should mostly dissipate during the evening hours. For Monday soundings show more of a cap in place, so rain chances look to be less than Sunday. However, isolated to scattered showers and storms will still be possible. Highs will be in the mid 80s. A cold front will approach and move through the area during the Tuesday through Wednesday time frame. There is still quite a bit of discrepancy in the timing of this frontal passage. Thus, have gone with pops over a wider time frame than is expected with the frontal passage to account for uncertainty. For now, it looks like Tuesday/Tuesday night will be the best chance for showers and storms. However, if slower solutions pan out, chances will linger into Wednesday. The timing issue with the front will also have quite an impact on temperatures mid week as a trough will move in behind this system. This will usher in cooler air for the end of the week. Highs Thursday and Friday will be in the lower to mid 60s with lows in the upper 40s. There may be a slight chance of rain toward the end of the long term as a weak disturbance moves through the flow aloft, but timing with these is usually fairly questionable this far out. && .AVIATION (18Z TAF Update)... Issued at 130 PM EDT Fri May 9 2014 Area of showers and isolated thunderstorms continues to progress east over east-central KY at this time. Conditions are currently VFR at LEX, but could briefly go MVFR around 1800-1830z with an area of moderate-to-heavy rain approaching. Otherwise, conditions will remain VFR at LEX, as well as SDF and BWG this afternoon in the wake of the rain. Winds this afternoon will remain gusty up to 20 kts from the S-SW then stay more steady from 5-12 kts tonight. Then, attention turns to developing thunderstorms over MO near a frontal boundary. Air mass ahead of these storms will destabilize resulting in additional development this afternoon. Scattered to numerous storms could then move into central KY, including SDF and BWG this evening in the 00-06z time frame. With this in mind, have indicated a TEMPO group for a few hours for thunderstorms and MVFR conditions to try to narrow down the best expected time of occurrence. The expected convection should also reach LEX later tonight, although probably in a weakening state. Thereafter, coverage should wane, but can`t rule out isolated or scattered showers and storms the rest of the night, so have kept VCTS and VCSH in at all TAFs. On Saturday, could be isolated or scattered showers around in the morning, with scattered diurnal storms again possible in vicinity of SDF from 18-00z. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........TWF Long Term.........EER Aviation..........TWF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
145 PM EDT Fri May 9 2014 ...Updated Aviation Discussion... ...Forecast Update... Issued at 1145 AM EDT Fri May 9 2014 Band of showers continues to progress northeast over central KY at this time. There has not been any thunderstorms in this area so far, although latest Doppler radar is now showing increasing reflectivity values over parts of central KY, some expect isolated/scattered embedded cells early this afternoon as the rain continues pushing east. The rain will exit our eastern forecast area by 19z or so. After the rain ends, dry weather should prevail for a few hours this afternoon over central KY and south-central IN given the absence of enough forcing and initial instability. In the wake of this rain, clouds should thin with some breaks of sun, which should allow temperatures to reach near/around 80 in our western forecast area. Low-level warming combined with increasing mid-level lapse rates will increase instability over the lower OH Valley this afternoon as shown nicely by latest model soundings. Already, scattered cells are developing in central MO near frontal zone, although these should move northeast later today and initially not affect our area. Nevertheless, with increasing instability and potential diurnal heating boundaries, at least scattered convection should also develop later this afternoon just to out west and move into central KY and southern IN late this afternoon/evening. No major changes to tonight`s forecast at this time. Issued at 915 AM EDT Fri May 9 2014 An elongated axis of showers with a couple embedded bands of moderate to heavy rain and possibly an embedded elevated thunder- storm is moving northeast quickly this morning over west-central KY, now moving through our western forecast area. 06z model runs along with latest high-resolution HRRR model show that this axis should move steadily but coherently through our forecast area for the rest of this morning into early afternoon, before exiting to our east. Thus, have raised rainfall probabilities across our entire area. After this rain passes by, precip will end and then the question arises about what will happen later this afternoon. Still looks like some diurnal heating will commence with the atmosphere becoming more unstable. Models show that scattered convection could develop to our west this afternoon and then move east into our area later this afternoon and tonight. This scenario still seems reasonable, although am not able to pin things down more specifically at this time yet. Will continue to monitor trends through the day. No change to temperatures for today at this time. Will evaluate this later this morning into early afternoon. Issued at 640 AM EDT Fri May 9 2014 Did a quick update to back off PoPs a bit in the east this morning, but also increase PoPs slightly across our west and northwestern areas. Based on latest radar trends, expect a band of showers to affect portions of southern Indiana and Kentucky west of I-65 this morning. Expect this activity to diminish in intensity and coverage as it heads into a slightly drier and more stable airmass. Also backed off coverage this afternoon a bit given that overall model solutions are trending a bit drier. Likely PoPs appear to be too aggressive at this time and have backed them off into the scattered category. Also bumped temperatures in the west up slightly based on the assumption of lesser precipitation. .SHORT TERM (Now through Saturday)... Issued at 315 AM EDT Fri May 9 2014 In the near term, partly to mostly cloudy skies will be the rule across southern Indiana and central Kentucky this morning. Early morning IR imagery shows plenty of high level cloudiness streaming in from the west. Area radars are rather quiet across central KY but there are some returns back over southeastern Missouri that are heading eastward. We expect dry conditions for the remainder of the early morning hours. Temperatures remain quite mild with readings generally in the upper 60s to the lower 70s. Some of our cooler spots appear to have decoupled a bit and are seeing temperatures down into the upper 50s to around 60. We expect temperatures to slowly drop a few more degrees before rebounding towards sunrise. For Today, local and national high resolution modeling suggest area of convection across southeastern Missouri and northeastern Arkansas will grow upscale early this morning in response to a moderate low-level jet axis impinging northeastward into lower Mississippi Valley. This convection will work eastward during the morning hours and weaken a bit as it heads into central Kentucky. Persistent cloud cover and the remnants of this convective activity will likely keep instability down to marginal levels across the region. That is not to say that some areas may see stronger convection develop this afternoon. As the morning convection heads off to the east, we may see a few breaks develop which could lead to the development of pockets of higher instability during the afternoon. The best chances of this occurring would be out across the western areas. Overall, we still do not believe today will be a total washout. Though areas that do receive rain could get a nice soaking as the showers and storms move through the region. Highs today look to range from the middle to upper 70s in the west with upper 70s to lower 80s in the east. As we move into the evening hours, the higher resolution models do show a secondary line of storms forming along the frontal boundary approaching from the northwest. These storms probably will fire along a line from Indianapolis to St. Louis early this evening and then spread eastward into our region during the overnight period. Depending on how fast the early morning activity clears the region will be a determining factor in how strong the evening/overnight convection will be. With the line expected to come through at the time of minimum heating, we are not overly impressed with severe potential. Strong storms are certainly possible with damaging winds and hail being the primary threats. The activity should clear our region by early Saturday morning with temperatures only cooling into the mid-upper 60s. For Saturday, skies will likely start off mostly cloudy and then begin to clear from the west towards the east. While the upper flow takes on more of zonal pattern, there is difficulty in determining any real triggers for convection. Isolated-scattered convection will be possible with the highest concentration out toward the eastern portions of the forecast area. Though, by and large most areas will probably see mainly dry conditions. Highs for Saturday will be largely dependent on cloud cover during the afternoon. The multi-model consensus suggests highs in the upper 70s to near 80 in the west with mainly mid-upper 70s in the east. .LONG TERM (Saturday Night through Thursday)... Issued at 319 PM EDT Thu May 8 2014 As previously advertised, the Ohio Valley will be entering into an active pattern with showers and thunderstorms in the forecast for nearly every day in this period. Synoptically, Saturday will undergo a transition to more zonal at the 500mb level as the disturbance that brings rain to the region Friday night moves off toward the east. The forecast challenge for Saturday is how quickly the storms exit the forecast area as the deterministic models are struggling to come into better agreement. The trend has been just a bit slower, as evident from comparing previous runs with the 12Z runs. The NAM has been the quickest and conversely, the GFS messy and the slowest. The 09Z SREF seems to be the better compromise and have leaned toward it to show a general partial clearing from west to east throughout the day. Through the remainder of the weekend, much of Saturday night should be dry before the atmosphere recharges ahead of the next system. We`ll remain under southerly flow with high pressure centered over the Atlantic, allowing for GoMex moisture to pool into the region. Under this warm , moist air advection regime, Sunday`s forecast is also a bit tricky as we could see some sporadic storms firing up, especially with diurnal heating throughout the day. There is no obvious signal for which portions of the forecast area will see better rain chances than others given this type of setup so have broad brushed low-end chance PoPs throughout. After the sun sets on Sunday, should see a wane in storm coverage with the loss of the aforementioned heating. Something to watch for, however, is that the 12Z NAM is hinting at a mesoscale convective system to build across eastern KS/central MO and race off into the Great Lakes region late Saturday night through Sunday. This is in response to a surface low that develops just behind it. The NAM is depicting the eastern portion of this system to break off and jet across central KY before dying out as it loses its forcing mechanism. We`ll have to see how this evolves as we approach that time frame. As if the models haven`t been struggling enough, true temporal divergence becomes evident early next week as an amplified pattern sets up: troughing across the Plains and ridging over the East Coast. The GFS has been consistently fast with the ECMWF much slower. Have attempted to blend and compromise between the two, coming to the uncertain conclusion that Tuesday looks to be the best chance for active weather across the area. One thing the models do agree on is the pattern change coming by the middle to end of next week. Given the unsettled nature of the upcoming pattern, temperature forecasts will be difficult to nail down with certainty, with clouds potentially wrecking havoc on the highs/lows. However, taking into consideration the type of airmasses we`ll be under, along with climo for this time of year, the warmest days of the long-term period will be Sunday and Monday, with Saturday and Tuesday being slightly cooler, and Wednesday onward dropping well below normal. This forecast update will show highs in the upper 70s on Saturday as clouds and precip exit; highs in the lower 80s Sunday - Monday under southerly flow/WAA; Tuesday in the mid to upper 70s with stormy conditions; and 60s Wednesday - Thursday. Look for lows to respond accordingly with 60s Saturday night - Monday night and flirting with the 50 degree mark Tuesday night - Wednesday night. && .AVIATION (18Z TAF Update)... Issued at 130 PM EDT Fri May 9 2014 Area of showers and isolated thunderstorms continues to progress east over east-central KY at this time. Conditions are currently VFR at LEX, but could briefly go MVFR around 1800-1830z with an area of moderate-to-heavy rain approaching. Otherwise, conditions will remain VFR at LEX, as well as SDF and BWG this afternoon in the wake of the rain. Winds this afternoon will remain gusty up to 20 kts from the S-SW then stay more steady from 5-12 kts tonight. Then, attention turns to developing thunderstorms over MO near a frontal boundary. Air mass ahead of these storms will destabilize resulting in additional development this afternoon. Scattered to numerous storms could then move into central KY, including SDF and BWG this evening in the 00-06z time frame. With this in mind, have indicated a TEMPO group for a few hours for thunderstorms and MVFR conditions to try to narrow down the best expected time of occurrence. The expected convection should also reach LEX later tonight, although probably in a weakening state. Thereafter, coverage should wane, but can`t rule out isolated or scattered showers and storms the rest of the night, so have kept VCTS and VCSH in at all TAFs. On Saturday, could be isolated or scattered showers around in the morning, with scattered diurnal storms again possible in vicinity of SDF from 18-00z. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........TWF Short Term.....MJ Long Term......BJS Aviation.......TWF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1118 AM CDT Fri May 9 2014 .MESOSCALE DISCUSSION... Issued at 1117 AM CDT FRI MAY 9 2014 The explicit convection producing guidance, 3km HRRR, as well as the 13km RUC is doing a fairly decent job of depicting the departing and new convective activity in Missouri as of 16z Friday. WFO LSX noted that pea (1/4") hail was reported near Steelville MO in the axis of 600+ CAPE. This axis should continue to translate eastward and increase to between 1000-1500 J/KG per the 13km RUC between 17z-20z. Mid-level winds are a little stronger than forecast between 700mb-500 mb which may accelerate the timing and cooling aloft with the storms as they move through Southeast Missouri and Southern Illinois. If the convection can tap the stronger mid-level shear enough to enhance updrafts, larger than dime/quarter size hail may be a real possibility. The GOES Sounder Water Vapor difference channels 7.0 micron (sensitive near 700 mb) and 7.4 micron (sensitive near 850 mb) suggesting a sharp drying aloft moving from Oklahoma into Southwest MO ast of 1447z today. This may sharpen updraft with sharper lapse rates aloft as storms move near the Carter to Perry County MO county western borders, into Perry and Jackson IL county later this afternoon. Upper level support has been forecast to be more persistent over Southern IL...mainly between Interstate 64 corridor and Route 13, so would not be surprised to see more robust updrafts, producing severe hail and damaging wind gusts in that area for a more prolonged period. Still could see some good storms in Southeast Missouri as well as the afternoon progresses. As we get into late evening, between 10 pm-11 pm CDT...could see flow transition into a more repeating shower or thunderstorm concern...with training of echoes fore more overnight persistent rain along and mainly south of the Ohio River, but including Southwest Indiana and the delta region of Southeast Missouri, just north of the Bootheel. && .UPDATE... Issued at 1117 AM CDT FRI MAY 9 2014 Interim morning update to reflect marked changes in PoP, weather, sky cover, and temperature/dewpoint to reflect recharging of atmosphere between early morning MCS and new convective activity on central and southern Missouri. && .SHORT TERM...(Today through Sunday night) Issued at 234 AM CDT FRI MAY 9 2014 With the approach of a frontal system and attendant H5 trough, shower and thunderstorm activity will increase from west to east across the region today. With the flow aloft nearly parallel to the front combined with surface high pressure firmly planted over the southeast US, the front will have difficulty making it too far east over the next 18 to 24 hours. Latest guidance shows the front moving into the western sections of our CWA this afternoon, becoming quasi-stationary over the northern sections by Saturday morning, then lifting back to the north as a warm front on Saturday. With the front forecast to be in the vicinity, precipitation chances are greatest today and tonight. There is a slight risk of a few storms becoming severe this afternoon with large hail and damaging winds being the main hazards. Precipitation forecast confidence rather low Saturday, Saturday night, and Sunday as our area will be in the warm sector and mid level temperatures not that impressive. Low level forcing will be negligible but ripples of mid level energy will continue to track across left-over deep moisture, and models not in the best agreement on where the moisture will be. Sunday night as the next weather system takes shape over the plains, the flow aloft turns more southwest forcing the ridging over the southeast to build northwest into our neck of the woods. This should limit any precipitation chances to the far northwestern and western sections of our CWA. Temperatures will stay at or above normal through the period. .LONG TERM...(Monday through Thursday night) Issued at 234 AM CDT FRI MAY 9 2014 To start out the long term period, we will be watching the evolution of an upper trough that will be positioned in the Rockies on Monday. As this feature slowly moves east, a sfc frontal boundary will be making its way toward the region. It is looking more and more that Monday might end up being dry as we wait for the incoming front. Best chances late in the day will be in parts of southeast MO and southern IL. There continues to be timing issues between the GFS and ECMWF, with the GFS continuing to be the faster model but looking back on previous runs, both models have slowed down a bit with timing. The ECMWF seems to keep a much stronger upper high in place over the southeastern states which slows down the progression of the aforementioned upper trough. The 12Z ECMWF barely has the front into the area by 12Z Tuesday, with precip knocking on our western door, while the 00Z GFS is showing a pretty stormy Monday night period going into Tuesday. The 00Z ECMWF is a bit faster but still not as fast as the GFS. The front continues to move east during the day on Tuesday and plan on keeping likely pops right now as there seems to be good consistency for that day so far. When to exit the precipitation though, will be another story. The 00Z GFS moves the activity out of the area Tuesday night while the slower ECMWF takes until Wednesday morning to dry us out. Plus, the 00Z ECMWF indicates another wave of precipitation coincident with the main upper trough as it moves through Tuesday night into early Wednesday. These timing issues also play a big role in determining temperatures. The faster GFS is indicating that the colder air will filter in as early as Tuesday, making for a much cooler day than the slower ECMWF would suggest. Wednesday`s temps though will be a bit easier since we should have the colder air mass into the area by then. With 850 mb temps in the single digits, we will definitely feel like fall has returned briefly, as we struggle to get out of the 60s in some places. Looking at some of the CIPS analog guidance, there is even more confidence that highs in the 60s appear likely with this colder air mass coming in. Highs in Thursday will be even more of a challenge since the GFS turns winds around to southerly, which warms us up, but the ECMWF maintains a colder northwest wind. && .AVIATION... Issued at 642 AM CDT FRI MAY 9 2014 At KCGI/KPAH MVFR cigs/vsbys possible between 20-02Z in TSRA... otherwise VFR. At KEVV/KOWB MVFR cigs/vsbys in TSRA between 12-16Z, then again between 23-04Z...otherwise VFR. Southerly winds aob 10 knots early should increase to 10-12 knots with gusts up to 18-20 knotsafter 15Z, then drop back to aob 10 knots after 00Z. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ MESOSCALE...Smith UPDATE...Smith
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
116 PM CDT FRI MAY 9 2014 .AVIATION... AFTER A MORNING OF IFR CEILINGS AND VCTS ACROSS SEVERAL TERMINALS... CEILING`S HAVE LIFTED AND OUR SCATTERED OUT ACROSS SOME TERMINALS EARLY THIS AFTERNOON. STILL DEALING WITH MVFR CONDITIONS HOWEVER AT THE ELD/LFK AND SHV TERMINALS. THIS SHOULD BE TEMPORARY WITH CEILING`S LIKELY CLIMBING ABOVE 3KFT OVER THE NEXT HOUR OR SO. CONVECTION FOR THE MOST PART HAS MOVED SOUTH AND EAST OF OUR TERMINALS BUT LEFT MENTION OF VCTS AT THE LFK/MLU TERMINALS THROUGH THE AFTERNOON. HRRR SHOWING REDEVELOPMENT ACROSS THE REGION LATER THIS AFTERNOON...AND FOR THAT REASON...HAVE REINTRODUCED VCTS AT SEVERAL TERMINAL LOCATIONS THROUGH THE EVENING. BY LATE EVENING/OVERNIGHT...MOS CEILING CATEGORIES SUPPORT A RETURN OF MVFR/IFR CEILINGS AREAWIDE WITH SOME 3-5SM VISIBILITIES. KEPT THIS RUNNING THROUGH AT LEAST MID MORNING ON SATURDAY WITH IFR CEILINGS LIKELY NOT LIFTING UNTIL AFTER 15Z ON SATURDAY. 13 && .PREV DISCUSSION... /ISSUED 1126 AM CDT FRI MAY 9 2014/ DISCUSSION... ONGOING CONVECTION MAINLY SOUTH OF I-20 LATE THIS MORNING WITH SOME IMPRESSIVE RAINFALL RATES/TOTALS ACROSS PARTS OF DEEP E TX...PROMPTING A FLASH FLOOD WARNING FOR THIS AREA. ELSEWHERE ALONG AND SOUTH OF I-20...JUST SPOTTY SHWRS AND A FEW TSTMS NOTED ON RADAR WITH CLOUDS TRYING TO ERODE OVER PORTIONS OF NE TX WITH A COLD FRONTAL BNDRY JUST TO OUR WEST. THIS BNDRY IS EXPECTED TO WEAKEN AND TRACK JUST NORTH OF OUR REGION THIS AFTERNOON WITH A FEW UPPER LEVEL DISTURBANCES TRANSITIONING EWRD WITH THE FRONT. THEREFORE...ADDITIONAL CONVECTION IS EXPECTED TO DEVELOP LATER THIS AFTERNOON WITH SOME STRONG TO POSSIBLY ISOLD SEVERE TSTMS. THE THREATS WITH ANY OF THESE TSTMS WILL BE LIMITED TO DAMAGING WINDS AND HAIL AS INDICATED BY THE DAY 1 SPC CONVECTIVE OUTLOOK. AS FAR AS CHANGES TO THE FORECAST...DID MAKE UPWARD ADJUSTMENTS TO POPS MAINLY ALONG AND SOUTH OF I-20 WHERE MORNING CONVECTION IS CONCENTRATED. ALSO LOWERED FORECAST HIGHS JUST A BIT CONSIDERING THE ABUNDANT CLOUD COVER AND CONVECTION...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A FEW AREAS SQUEAK OUT MID OR EVEN UPPER 80S WHERE CLOUDS BREAK EARLIER AND CONVECTION IS KEPT AT BAY. NEW QPF NUMBERS HAVE ALSO BEEN LOADED INTO THE GRIDS. UPDATED PRODUCTS HAVE ALREADY BEEN SENT. /19/ && .PRELIMINARY POINT TEMPS/POPS... SHV 68 87 70 86 71 / 20 20 20 20 20 MLU 67 87 69 86 69 / 30 20 20 20 20 DEQ 64 86 67 84 70 / 20 20 20 20 20 TXK 67 86 68 85 68 / 20 20 20 20 20 ELD 66 86 68 85 68 / 30 20 20 20 20 TYR 68 87 70 86 71 / 20 20 10 20 20 GGG 67 88 69 86 71 / 20 20 10 20 20 LFK 69 88 71 87 72 / 20 20 10 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 13
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
400 PM EDT FRI MAY 9 2014 .SHORT TERM...THIS EVENING AND TONIGHT CLOUDS AND SHALLOW EARLY AFTERNOON CONVECTION HAVE RESULTED IN A RATHER NEBULOUS PICTURE FOR THUNDERSTORM POTENTIAL THIS EVENING. ABUNDANT MID AND HIGH CLOUDS HAVE LIMITED BOUNDARY LAYER RECOVERY IN THE WAKE OF THE PASSING CONVECTION, ALTHOUGH MID 70S TEMPS AND DEWPOINTS AROUND 60 ARE MAKING A RENEWED PUSH INTO SOUTHWEST LOWER MICHIGAN DURING THE MID AFTN AND CLOUD OPACITY IS DECREASING. MESOANALYSIS SHOWS MUCAPES AT A RATHER MODEST 500 J/KG OVER WESTERN LOWER FOR NOW...BUT THE 12Z NAM AND RECENT RUNS OF THE RUC SUGGEST A RECOVERY TO 1000 J/KG CAPE BY AROUND 22Z IN ADVANCE OF THE APPROACHING COLD FRONT. THE OVERZEALOUS HANDLING OF QPF BY TODAY`S NWP MAKES THE PROGGED RECOVERY ALL THE MORE IMPRESSIVE. HOWEVER, IN AND AN ATTEMPT TO ADDRESS UNCERTAINTIES REGARDING BOTH THE MID-LEVEL AND LOW-LEVEL THERMODYNAMIC ENVIRONMENT RESULTING FROM BOTH POOR MODEL PERFORMANCE AND EARLY CONVECTION, A SPECIAL SOUNDING WAS LAUNCHED AT APPROXIMATELY 1930Z. THE DATA WILL BECOME AVAILABLE SHORTLY AFTER ISSUANCE OF THE AFTERNOON PACKAGE. FINALLY, ALTHOUGH ANY CONVECTION THAT BUBBLES UP IN ADVANCE OF THE FRONT MAY BEGIN TO LOOSE FOOTING IN THE BOUNDARY LAYER AROUND 00Z...STEEPENING MID-LEVEL LAPSE RATES WILL MAINTAIN RESPECTABLE MID-LEVEL INSTABILITY WELL INTO THE EVENING HOURS AND MAY EVEN ALLOW A HAIL THREAT TO DEVELOP IN ADDITION TO WIND AS UPDRAFTS ARE ALLOWED TO DEEPEN. WIDESPREAD SEVERE WEATHER IS NOT EXPECTED...PARTICULARLY GIVEN PARALLEL NATURE OF THE MEAN FLOW TO THE INITIATING BOUNDARY...BUT AT LEAST A MARGINAL THREAT WILL EXIST DEPENDING ON THE BEHAVIOR OF INDIVIDUAL CELLS. WILL MAINTAIN CHANCE POPS THROUGH THE EVENING HOURS AND MENTION A RISK OF AT LEAST ISOLATED WIND/HAIL THREATS DEVELOPING OVER THE NEXT SEVERAL HOURS IN THE HWO. THE GREATEST THREAT WILL BE FOCUSED FURTHER SOUTH AND WEST WHERE INSTABILITY WILL BE MAXIMIZED. && .LONG TERM... DIFFERENTIAL HEIGHT RISES BEHIND THE DEPARTING SHARP MIDLEVEL TROUGH AXIS WILL LEAD TO A SURFACE RIDGE ACROSS SOUTHEASTERN MICHIGAN ON SATURDAY. DRYING SIGNAL IN THE 925-850MB LAYER SUPPORTS THE FORECAST SOUNDINGS OF LCL HEIGHTS EVENTUALLY REACHING A VERY HIGH 6000 FT AGL. THE ENVIRONMENT FAVORABEL FOR DEEP TURBULUENT MIXING WILL EVENTUALLY ALLOW BREEZY WESTERLIES TO DEVELOPM DURING THE LATE AFTERNOON. SURFACE WIND GUSTS ARE EXPECTED TO REACH 25 TO 30 KNOTS. FORECASTED SOUNDINGS FOR SATURDAY ARE NOW QUITE A BIT DIFFERENT WITH ANY EXPECTED MIDLEVEL LAPSE RATES. IN FACT...POCKET OF STEEP MIDLEVEL LAPSE RATES IS NOWHERE TO BE SEEN...SUGGESTING THAT EVEN A SCATTERED CU FIELD WILL BE DIFFICULT. HIGHS SATURDAY WILL BE COOLER...READING REACHING THE UPPER 60S FOR MANY AREAS...72 OR 73 DEGREES FOR THE HIGHER SURFACE PRESSURE/LOWER TERRAIN LOCATIONS ACROSS THE EXTREME SOUTHEAST. THE INBOUND LONGWAVE RIDGE WILL BE VERY PROGRESSIVE DURING THE LATTER HALF OF THE WEEKEND...AMPLIFYING AS WELL. PRECEDING MID TO UPPER LEVEL TROPSOPHERIC DEFORMATION IS PROGGED TO BE VERY GOOD WHICH WILL AID IN THE RAPID DEVELOPMENT OF A WARM FRONT BY SUNDAY. EARLY PART OF THE DAY IS EXPECTED TO BE QUIET WITH VERY DRY AIR IN RESIDENCE DURING THE MORNING. WIND TRAJECTORIES WILL EVENTUALLY VEER SOUTHWESTERLY WHICH WILL ALLOW WARMTH AND INSTABILITY TO INCREASE FOR THE AFTERNOON. THE SUNDAY PERIOD HAS BEEN A NOISY ONE WITHIN THE MODELS SO CONFIDENCE IS NOT OVERLY HIGH...ESPECIALLY WITH REGARDS TO TIMING. HOWEVER...ENOUGH UPPER LEVEL FORCING APPEARS TO BE COMING TOGETHER SUPPORTIVE OF A MID CHANCE POP IN THUNDERSTORMS FOR THE SOUTHERN HALF OF THE CWA. THE LATE AFTERNOON PUSH WITH WARMTH WILL ALLOW TEMPERATURES TO REACH THE MID 70S FOR MANY LOCATIONS. MONDAY WILL BEGIN A PERIOD OF ACTIVE WEATHER FOR THE EXTENDED AS A WARM FRONT LIFTS NORTH INTO THE TRI CITIES AREA. AGAIN...WARM AND MOIST AIR WILL ADVECT NORTH VIA A 40KT H85 JET. THIS WILL BRING PWAT VALUES OVER 1.5 INCHES. WILL CONTINUE TO TREND UPWARD WITH POPS 50 TO 60 PERCENT. THE COLD FRONT WILL SWING THROUGH ON TUESDAY AND CONTINUE THE HIGH POP EVENT. BOTH DAYS POSE THE THREAT FOR THUNDER AS LI/S WILL BE NEGATIVE. MUCH LIKE THE PAST 2 DAYS HERE...MONDAY IN THE WARM SECTOR WILL REMAIN CAPPED BUT WITH CAPE WELL OVER 2500 J/KG. TUESDAY WILL HAVE MORE POTENTIAL WITH THE STRONGER FORCING...BUT LOWER CAPE VALUES. CHANCE POPS WILL ALSO BE IN THE FORECAST WEDNESDAY AS REMNANT MOISTURE FROM THE SLOW CHURNING LOW PRESSURE REMAINS PROXIMAL TO THE AREA. THIS WILL BE ALONG WITH A GENERAL THUNDER THREAT. THE REST OF THE PERIOD STILL LOOKS TO REMAIN COOL WITH TEMPS BELOW CLIMO. && .MARINE... A STRONGLY STABLE PROFILE OVER THE GREAT LAKES WILL KEEP WIND GUSTS MAINLY UNDER 30 KNOTS. THE COLD FRONT WILL TRACK ACROSS LAKE HURON THIS EVENING AND WILL BE MARKED BY A VEERING OF THE WIND TO THE SOUTHWEST. THE POST FRONTAL COLD AIR ADVECTION IN THE WAKE OF THE FRONT WILL NOT BE SIGNIFICANT ENOUGH TO OVERCOME THE STRONG OVER LAKE STABILITY. THUS WINDS WILL REMAIN MAINLY UNDER 25 KNOTS ON SATURDAY. WINDS WILL QUICKLY DIMINISH SATURDAY NIGHT AS SFC HIGH PRESSURE MOVES OVER THE LAKES. A WARM FRONT WILL SLOWLY LIFT ACROSS THE REGION SUN NIGHT THROUGH MONDAY NIGHT. THE CONTINUED STRONG STABILITY WILL KEEP WINDS AND WAVES IN CHECK. HOWEVER...THERE WILL BE A GOOD CHANCE FOR THUNDERSTORMS THROUGH THE PERIOD. && .AVIATION...ISSUED 1251 PM EDT FRI MAY 9 2014 //DISCUSSION... SHODDY COVERAGE OF PRECIPITATION ACROSS THE LOWER PENINSULA THIS MORNING WILL SUPPORT AN INCREASED RISK OF INSTABILITY CAPABLE OF SUPPORTING ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT THIS AFTERNOON. INITIAL BAND OF SHOWERS LIFTING ACROSS SOUTHEAST MICHIGAN AROUND 17Z WILL EXIT THE AREA SHORTLY AND WILL BE FOLLOWED BY A LULL PRIMARILY CONSISTING OF VFR...OCCASIONAL LIGHT RAINFALL...AND POCKETS OF LOW VFR CEILING. REDEVELOPMENT IS EXPECTED MID-AFTERNOON WITH AN INCREASED RISK OF SOME STORMS BECOMING STRONG TO SEVERE. GUSTY SOUTH-SOUTHWEST FLOW WILL PERSIST THROUGH THE EVENING BEFORE VEERING TO A MORE WESTERLY DIRECTION IN THE WAKE OF THE COLD FRONT AFTER 00Z. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS BELOW 5KFT * MEDIUM CONFIDENCE THAT TSTORMS WILL IMPACT KDTW && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...JVC LONG TERM....CB/MM MARINE.......CB AVIATION.....JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
346 PM EDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 444 AM EDT FRI MAY 9 2014 THE UPPER TROUGH THAT HAS BEEN CONTROLLING OUR WEATHER FOR THE LAST COUPLE OF DAYS IS CURRENTLY MOVING NORTHEAST THROUGH THE CENTRAL PLAINS. MOISTURE LADEN AIR STREAMING NORTHEAST AHEAD OF THIS TROUGH CAN BE SEEN ON WV IMAGERY EARLY THIS MORNING...WHICH IS HELPING TO FUEL SHOWERS AND ISOLATED THUNDERSTORMS FROM WESTERN LAKE SUPERIOR THROUGH PORTIONS OF UPPER MICHIGAN...AND SOUTHEAST TO EASTERN WISCONSIN. AT THE SURFACE...A 998MB LOW IS LOCATED JUST SOUTHWEST OF DULUTH AND A WARM FRONT STRETCHES EAST ALONG THE U.P. AND WISCONSIN BORDER. SHORTWAVES EMBEDDED WITHIN THE WARM MOIST SOUTHWESTERLY FLOW CONTINUES TO PRODUCE AREAS OF THUNDERSTORMS OVER THE WESTERN HALF OF THE GREAT LAKES REGION AND EXPECT THAT TO CONTINUE FOR AREAS WITHIN THE WARM/MOIST AIRMASS. AS THE LOW LIFTS NORTHEAST TODAY...THE COLD FRONT (CURRENTLY STRETCHING SOUTH FROM SOUTHEAST MINNESOTA THROUGH NORTHERN MISSOURI) WILL SWEEP NORTHEAST ACROSS THE UPPER GREAT LAKES REGION. WITH THE SHOWER/THUNDERSTORM COVERAGE STARTING TO BECOME MORE SCATTERED/ISOLATED...WILL FOLLOW THAT IDEA FOR POPS AHEAD OF THE COLD FRONT. ALREADY STARTING TO SEE THE AFFECT OF THE DRYING ALOFT OVER NORTHWEST WISCONSIN AND EXPECT THE LAST AREAS OF SHOWERS FOR THIS MORNING TO PUSH THROUGH WESTERN UPPER MICHIGAN OVER THE NEXT COUPLE OF HOURS. AS THAT DRYING SHIFTS EAST THIS MORNING...WILL DIMINISH POPS FROM WEST TO EAST DURING THE MORNING HOURS. WITH THERE STILL BEING SOME ISOLATED THUNDER ON THE BACK EDGE OF THE PRECIPITATION (EVEN THOUGH RAP ANALYSIS OF MUCAPE AND MID-LEVEL LAPSE RATE VALUES ARE VERY WEAK)...HAVE EXTENDED THE SLIGHT CHANCE OF THUNDER A LITTLE LONGER OVER THE EAST THIS MORNING TO COINCIDE WITH THE AXIS OF MOISTURE AND LATEST THUNDER AREAS. BEHIND THE COLD FRONT...MAY SEE A FEW PEAKS OF SUNSHINE OVER THE CENTRAL/EAST (WHERE FOG ISN/T OCCURRING) AS THIS MID LEVEL DRY SLOT MOVES THROUGH AND BEFORE THE NEXT WAVE OF LOW LEVEL MOISTURE AND PRECIPITATION (CURRENTLY IN THE EASTERN DAKOTAS AND WESTERN MINNESOTA) MOVES OVER THE AREA. WILL CONTINUE THE IDEA SHOWN IN THE PREVIOUS FORECAST OF ISOLATED TO SCATTERED SHOWERS MOVING OVER THE WEST OR NORTHWEST HALF OF THE CWA LATER THIS AFTERNOON AND CONTINUING THROUGH A GOOD PORTION OF THE NIGHT TONIGHT (ESPECIALLY THE KEWEENAW TONIGHT). QPF AMOUNTS WILL BE MUCH LIGHTER THAN SEEN OVER THE LAST COUPLE DAYS AND MAINLY BETWEEN A TRACE AND A COUPLE TENTHS. IN ADDITION...IT WILL BECOME BREEZY BEHIND THE COLD FRONT...WITH BUFKIT SOUNDINGS INDICATING GUSTS AROUND 25KTS OVER MUCH MUCH OF UPPER MICHIGAN TODAY. WITH THE COLD AIR ADVECTION IN PLACE THROUGH MUCH OF TONIGHT...THOSE GUSTS WILL LIKELY KEEP UP AS WINDS SHIFT TO THE WEST THROUGH THE NIGHT. WHILE THE KEWEENAW MAY BE PROTECTED SLIGHTLY TODAY...THE WINDS SHOULD REALLY KICK IN TONIGHT AS IT IS CLOSEST TO THE TIGHTEST PRESSURE GRADIENT WITH THE DEPARTING LOW AND RESULTING STRONGER WINDS JUST ABOVE THE SURFACE. EXPECT THERE TO BE A PERIOD THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS WHERE GUSTS IN THE KEWEENAW WILL BE BETWEEN 30-35KTS. FINALLY FOR TEMPERATURES...VALUES THIS MORNING HAVE BEEN CONSISTENT IN THE 50S OVER THE INTERIOR LOCATIONS...ALTHOUGH LOCATIONS NEAR THE COOLING OF THE GREAT LAKES HAVE BEEN BOUNCING UP AND DOWN DEPENDING ON THE WIND DIRECTION. WITH THE WARM START AND THE WARM FRONT PUSHING NORTHEAST THROUGH MUCH OF UPPER MICHIGAN TODAY...SHOULD SEE TEMPERATURES RISE INTO THE MID-UPPER 60S OVER THE CENTRAL/EASTERN CWA AND WHERE SOME SUNSHINE OCCURS WILL PROBABLY SEE SOME SITES HITTING THE 70 DEGREE MARK. COLDER AIR ARRIVING BEHIND THE COLD FRONT WILL LEAD TO FALLING TEMPS OVER THE WEST IN THE AFTERNOON AND THE REST OF THE AREA TOWARDS EVENING. THE CLOUD COVER TONIGHT WILL KEEP TEMPS A LITTLE ABOVE NORMAL AND HAVE LOWS IN THE LOWER 40S. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 343 PM EDT FRI MAY 9 2014 MAIN FCST CONCERNS FOR LATER IN THE WEEKEND INVOLVE POPS ASSOCIATED WITH SHRTWV FCST TO LIFT INTO THE UPR LKS SAT NGT INTO SUN OUT OF A DEEPENING TROF OVER THE W. A MORE IMPORTANT/WETTER LO PRES IS LIKELY TO IMPACT THE AREA ON MON INTO TUE WITH INCRSG SW FLOW ALF BTWN THE DEEPENING UPR TROF IN THE PLAINS AND BLDG UPR RDG OVER THE SE CONUS. SAT NGT/SUN...SHRTWV EJECTING OUT OF A DEEPENING UPR TROF OVER THE W IS FCST TO BE MOVING THRU SW MN AT 00Z SUN INTO THE UPR LKS BY 12Z SUN. BUT SINCE AN UPR RDG AXIS IS FCST TO SHARPEN OVER UPR MI TO THE NW OF BLDG MEAN RDG OVER THE SE CONUS AND ON SW FLANK OF MORE PERSISTENT TROFFING OVER SE CANADA THAT WL MAINTAIN A SOURCE OF LLVL DRY AIR...SUSPECT SHRA ASSOCIATED WITH THE SHRTWV APRCHG FM THE SW WL DIMINISH WITH TIME AND TOWARDS THE NE. IN FACT...BULK OF MODELS SHOW DIMINISHING DEEP LYR QVECTOR CNVGC/MID LVL RH AS THE SHRTWV MOVES THRU UPR MI. MAINTAINED FLAVOR OF GOING FCST SHOWING ARRIVAL OF CHC POPS FM THE SW ON SAT NGT BUT THEN DIMINISHING AS SHOWER AREA MOVES TO THE NE ON SUN. SUN NGT...AS STRONGER SHRTWV BEGINS TO EJECT OUT OF DEEPENING UPR TROF MOVING SLOWLY THRU THE ROCKIES...SFC LO PRES IS FCST TO ORGANIZE IN THE CENTRAL PLAINS TO THE SW OF SFC HI PRES EXTENDING FM FAR NW ONTARIO INTO THE UPR LKS. ALTHOUGH THE EVNG MAY BE DRY ESPECIALLY OVER THE N HALF OF THE CWA CLOSER TO DRY LLVL NE TRAJECTORIES OUT OF THE HI IN ONTARIO...MOST OF THE MODELS SHOW HIER MID LVL RH/SOME PCPN ARRIVING FM THE SW THRU THE NGT WITH SOME ISENTROPIC ASCENT N OF H85 WARM FNT FCST TO REACH SRN WI BY 12Z MON. WL MAINTAIN HI CHC/LIKELY POPS NEAR THE WI BORDER LATE AT NGT... WITH DCRSG POPS TO THE N TOWARD THE DRIER AIR. TENDED TO SHARPEN THE GRADIENT OF THE POPS ON THE NRN EDGE OF THE PCPN SHIELD TO REFLECT THE IMPACT OF THIS DRY AIR. MON THRU TUE...SHRTWV EJECTING OUT OF HI AMPLITUDE UPR TROF SHIFTING SLOWLY EWD INTO THE PLAINS WL CAUSE SFC LO IN THE CENTRAL PLAINS AT 12Z MON TO LIFT NNEWD AND THRU MN ON TUE. MODELS APPEAR TO BE MAINTAINING TREND TOWARD A SLOWER...FARTHER W TRACK FOR THE SFC LO...NOT SURPRISING CONSIDERING THE HI AMPLITUDE PLAINS TROF/ERN RDG PATTERN TAKING SHAPE. SINCE THE SFC LO IS TRENDING TO MOVE SLOWER TO THE NE AND THE UPR RDG IS STILL BLDG INTO THE GREAT LKS ON MON... SUSPECT WDSPRD WAD RA WL BE SLOWER TO MOVE N THRU THE CWA TO THE N OF WARM FNT HUNG UP TO THE S. WHEN THE SFC LO FINALLY SHIFTS TO THE N ON MON NGT/TUE...MORE WDPSRD SHRA/EVEN SOME TS ARE LIKELY TO MOVE N WITH H85 WARM FROPA/H85 TEMPS RISING TO 14C OVER THE SE CWA. ANY TS WL BE ELEVATED AS LONGER RANGE MODELS SHOW SFC WARM FNT REMAINING TO THE S WITH TRIPLE PT LO SHIFTING THRU NW LOWER MI TO THE SE OF OCCLUDED LO MOVING THRU MN. WITH PWAT FCST TO REACH 1.25-1.50 INCH/ UP TO 225 PCT OF NORMAL...HEAVY RA MAY FALL DURING THIS EVENT AND CAUSE RIVER LVLS TO RISE AGAIN. DRIER AIR ALF WL MOVE IN FM THE WSW ON TUE FOLLOWING OCCLUDED FROPA AND DIMINISH THE POPS. EXTENDED...AS SLOW MOVING UPR TROF SWINGS INTO THE GREAT LKS ON WED INTO FRI...A VERY COOL AIRMASS WITH H85 TEMPS AS LO AS -5C WL IMPACT UPR MI WX. WITH THE PASSAGE OF SEVERAL SHRTWVS AND A MOIST CYC FLOW...SOME -SHRA...MIXED WITH SOME SN...WL BE PSBL. SO MAINTAINED LO CHC POPS SHOWN BY THE MODEL CONSENSUS. PCPN DURING THE DAY SHOULD SHIFT TO MAINLY OVER THE INTERIOR AS THE COOLER LKS WL ACT AS A STABILIZING IFNLUENCE. BLO NORMAL TEMPS WL BE THE RULE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 139 PM EDT FRI MAY 9 2014 LOW PRESSURE TRACKING JUST NE OF UPPER MI WILL BRING A COLD FRONT WEST TO EAST ACROSS ALL SITES THIS AFTERNOON AND EVENING. ABUNDANT LOW-LEVEL MOISTURE AND UPSLOPE FLOW SHOULD RESULT IN IFR CIGS AT CMX AND IWD OVERNIGHT ALONG WITH -SHRA. DOWNSLOPE FLOW WILL LIMIT SAW TO MVFR CIGS. EXPECT ALL SITES TO BECOME VFR WITH CLEAR SKIES BY SAT MORNING AS DRY AIR PUSHES ACROSS THE AREA. DECENT MIXING AND STRONGER WINDS ALOFT WILL BRING GUSTY WINDS TO ALL SITES INTO SAT...ESPECIALLY FOR CMX...WHERE GUSTS OVER 30KTS WILL BE POSSIBLE LATE THIS EVENING THROUGH THE OVERNIGHT HOURS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 422 AM EDT FRI MAY 9 2014 A LOW PRESSURE SYSTEM NEAR DULUTH EARLY THIS MORNING WILL SLIDE NORTHEAST INTO ONTARIO TODAY. AS THIS OCCURS...WINDS WILL SHIFT AROUND TO THE SOUTHWESTERLY DIRECTION TODAY AND THEN TO THE WEST TONIGHT. EXPECT THE WINDS TO INCREASE FROM WEST TO EAST TODAY AND GENERALLY TO 25KTS TONIGHT...ALTHOUGH THERE COULD BE SOME GUSTS TO 30KTS OVER THE CENTRAL LAKE. THESE STRONGER WINDS...COMBINED WITH GRADUALLY DRYING LOWER LEVELS SHOULD LEAD TO A DIMINISHMENT OF THE DENSE FOG OVER LAKE SUPERIOR FROM SOUTHWEST TO NORTHEAST TODAY. OPTED TO EXTENDED THE DENSE FOG ADVISORY FOR LAKE SUPERIOR INTO THE AFTERNOON HOURS TO BETTER MATCH UP WITH THE INCREASING WINDS AND DRIER AIR. A HIGH PRESSURE RIDGE WILL THEN SLIDE OVER THE AREA ON SATURDAY AND LEAD TO WINDS FALLING BELOW 15KTS SATURDAY NIGHT. THESE LIGHT WINDS WILL REMAIN THROUGH SUNDAY EVENING. A LOW PRESSURE SYSTEM MOVING TOWARDS THE UPPER GREAT LAKES REGION FROM THE CENTRAL PLAINS ON SUNDAY NIGHT WILL LEAD TO INCREASING EASTERLY WINDS (TO 25KTS BY MONDAY EVENING). THEN AS THE LOW SHIFTS NORTHEAST INTO ONTARIO ON TUESDAY...WINDS WILL SHIFT TO THE SOUTHWEST AND STAY BELOW 20KTS. && .HYDROLOGY... ISSUED AT 343 PM EDT FRI MAY 9 2014 RUNOFF FROM RECENT HEAVY RAIN...THAT REACHED UP TO AN INCH OR TWO AT SOME PLACES OVER NW UPR MI THE PAST FEW DAYS...AND MELTING OF THE LINGERING SNOW PACK OVER THE HIER TERRAIN ACCELERATED BY THE ARRIVAL OF WARMER...RATHER HUMID AIR /SFC DEWPTS IN THE 50S/ HAVE CAUSED AREA RIVER LEVELS TO RISE AGAIN...ESPECIALLY OVER THE W HALF OF UPR MI. THE TRAP ROCK RIVER IN HOUGHTON COUNTY ROSE ABOVE FLOOD STAGE EARLY THIS MRNG TO THE HIEST LEVEL ON RECORD /10.8 FT/...AND THE STURGEON RIVER AT ALSTON AND CHASSELL ARE ALSO ABOVE BANKFULL. FORTUNATELY...ONLY SOME SCATTERED LIGHT SHOWERS ARE IN THE FORECAST FOR TONIGHT AND SAT NIGHT INTO SUN...WITH A DRY DAY FOR MOST ON SAT. SINCE THE TRAP ROCK IS A NOTORIOUSLY FAST RESPONDING STREAM...THIS RIVER HAS ALREADY FALLEN BELOW FLOOD STAGE AS THE SHORTER TERM HEAVY RAIN RUNOFF HAS ALREADY FLOWED THROUGH THAT BODY OF WATER. BUT ADDITIONAL RUNOFF FROM PAST RAIN AND THE MELT DOWN OF THE REST OF THE SNOW PACK WILL ALLOW SLOWER RESPONDING RIVERS TO CONTINUE RISING INTO THE WEEKEND. THE ADVISORIES FOR THE STURGEON RIVER AT ALSTON AND CHASSELL ARE IN EFFECT INTO SUN. OVERALL...STREAMS AND RIVERS WILL REMAIN HI INTO NEXT WEEK...WITH ADDITIONAL HEAVY RA POSSIBLE ON MON INTO TUE. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS IN CASE ADDITIONAL FLOOD WARNINGS OR ADVISORIES ARE NECESSARY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ248-250. && $$ SHORT TERM...SRF LONG TERM...KC AVIATION...KLUBER MARINE...SRF HYDROLOGY...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
140 PM EDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 444 AM EDT FRI MAY 9 2014 THE UPPER TROUGH THAT HAS BEEN CONTROLLING OUR WEATHER FOR THE LAST COUPLE OF DAYS IS CURRENTLY MOVING NORTHEAST THROUGH THE CENTRAL PLAINS. MOISTURE LADEN AIR STREAMING NORTHEAST AHEAD OF THIS TROUGH CAN BE SEEN ON WV IMAGERY EARLY THIS MORNING...WHICH IS HELPING TO FUEL SHOWERS AND ISOLATED THUNDERSTORMS FROM WESTERN LAKE SUPERIOR THROUGH PORTIONS OF UPPER MICHIGAN...AND SOUTHEAST TO EASTERN WISCONSIN. AT THE SURFACE...A 998MB LOW IS LOCATED JUST SOUTHWEST OF DULUTH AND A WARM FRONT STRETCHES EAST ALONG THE U.P. AND WISCONSIN BORDER. SHORTWAVES EMBEDDED WITHIN THE WARM MOIST SOUTHWESTERLY FLOW CONTINUES TO PRODUCE AREAS OF THUNDERSTORMS OVER THE WESTERN HALF OF THE GREAT LAKES REGION AND EXPECT THAT TO CONTINUE FOR AREAS WITHIN THE WARM/MOIST AIRMASS. AS THE LOW LIFTS NORTHEAST TODAY...THE COLD FRONT (CURRENTLY STRETCHING SOUTH FROM SOUTHEAST MINNESOTA THROUGH NORTHERN MISSOURI) WILL SWEEP NORTHEAST ACROSS THE UPPER GREAT LAKES REGION. WITH THE SHOWER/THUNDERSTORM COVERAGE STARTING TO BECOME MORE SCATTERED/ISOLATED...WILL FOLLOW THAT IDEA FOR POPS AHEAD OF THE COLD FRONT. ALREADY STARTING TO SEE THE AFFECT OF THE DRYING ALOFT OVER NORTHWEST WISCONSIN AND EXPECT THE LAST AREAS OF SHOWERS FOR THIS MORNING TO PUSH THROUGH WESTERN UPPER MICHIGAN OVER THE NEXT COUPLE OF HOURS. AS THAT DRYING SHIFTS EAST THIS MORNING...WILL DIMINISH POPS FROM WEST TO EAST DURING THE MORNING HOURS. WITH THERE STILL BEING SOME ISOLATED THUNDER ON THE BACK EDGE OF THE PRECIPITATION (EVEN THOUGH RAP ANALYSIS OF MUCAPE AND MID-LEVEL LAPSE RATE VALUES ARE VERY WEAK)...HAVE EXTENDED THE SLIGHT CHANCE OF THUNDER A LITTLE LONGER OVER THE EAST THIS MORNING TO COINCIDE WITH THE AXIS OF MOISTURE AND LATEST THUNDER AREAS. BEHIND THE COLD FRONT...MAY SEE A FEW PEAKS OF SUNSHINE OVER THE CENTRAL/EAST (WHERE FOG ISN/T OCCURRING) AS THIS MID LEVEL DRY SLOT MOVES THROUGH AND BEFORE THE NEXT WAVE OF LOW LEVEL MOISTURE AND PRECIPITATION (CURRENTLY IN THE EASTERN DAKOTAS AND WESTERN MINNESOTA) MOVES OVER THE AREA. WILL CONTINUE THE IDEA SHOWN IN THE PREVIOUS FORECAST OF ISOLATED TO SCATTERED SHOWERS MOVING OVER THE WEST OR NORTHWEST HALF OF THE CWA LATER THIS AFTERNOON AND CONTINUING THROUGH A GOOD PORTION OF THE NIGHT TONIGHT (ESPECIALLY THE KEWEENAW TONIGHT). QPF AMOUNTS WILL BE MUCH LIGHTER THAN SEEN OVER THE LAST COUPLE DAYS AND MAINLY BETWEEN A TRACE AND A COUPLE TENTHS. IN ADDITION...IT WILL BECOME BREEZY BEHIND THE COLD FRONT...WITH BUFKIT SOUNDINGS INDICATING GUSTS AROUND 25KTS OVER MUCH MUCH OF UPPER MICHIGAN TODAY. WITH THE COLD AIR ADVECTION IN PLACE THROUGH MUCH OF TONIGHT...THOSE GUSTS WILL LIKELY KEEP UP AS WINDS SHIFT TO THE WEST THROUGH THE NIGHT. WHILE THE KEWEENAW MAY BE PROTECTED SLIGHTLY TODAY...THE WINDS SHOULD REALLY KICK IN TONIGHT AS IT IS CLOSEST TO THE TIGHTEST PRESSURE GRADIENT WITH THE DEPARTING LOW AND RESULTING STRONGER WINDS JUST ABOVE THE SURFACE. EXPECT THERE TO BE A PERIOD THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS WHERE GUSTS IN THE KEWEENAW WILL BE BETWEEN 30-35KTS. FINALLY FOR TEMPERATURES...VALUES THIS MORNING HAVE BEEN CONSISTENT IN THE 50S OVER THE INTERIOR LOCATIONS...ALTHOUGH LOCATIONS NEAR THE COOLING OF THE GREAT LAKES HAVE BEEN BOUNCING UP AND DOWN DEPENDING ON THE WIND DIRECTION. WITH THE WARM START AND THE WARM FRONT PUSHING NORTHEAST THROUGH MUCH OF UPPER MICHIGAN TODAY...SHOULD SEE TEMPERATURES RISE INTO THE MID-UPPER 60S OVER THE CENTRAL/EASTERN CWA AND WHERE SOME SUNSHINE OCCURS WILL PROBABLY SEE SOME SITES HITTING THE 70 DEGREE MARK. COLDER AIR ARRIVING BEHIND THE COLD FRONT WILL LEAD TO FALLING TEMPS OVER THE WEST IN THE AFTERNOON AND THE REST OF THE AREA TOWARDS EVENING. THE CLOUD COVER TONIGHT WILL KEEP TEMPS A LITTLE ABOVE NORMAL AND HAVE LOWS IN THE LOWER 40S. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 459 AM EDT FRI MAY 9 2014 PATTERN EVOLUTION DURING THE LONG TERM WILL BRING A RETURN OF A BUILDING RIDGE ALONG/NEAR THE W COAST OF NAMERICA THIS WEEKEND THRU THE FIRST HALF OF NEXT WEEK (POSITIVE ANOMALIES REACH THEIR MAX WED). THIS WILL FORCE A FAIRLY DEEP TROF FOR MID MAY TO AMPLIFY SOUTHWARD INTO THE CNTRL CONUS DURING THE EARLY PART OF NEXT WEEK WITH SLOW EASTWARD PROGRESSION THEREAFTER. THE BUILDING RIDGE WILL FORCE THE UPPER LOW/ENERGY NOW IN THE GULF OF ALASKA TO DIVE SE TOWARD THE SRN ROCKIES. AS THE ENERGY THEN LIFTS NE...ANOTHER ACTIVE LOW PRES SYSTEM WILL MOVE NE INTO THE UPPER MISSISSIPPI VALLEY ON A TRACK SIMILAR TO THE SYSTEM CURRENTLY AFFECTING THE MISSISSIPPI VALLEY/WRN GREAT LAKES. SO...AFTER A PERIOD OF DRY WEATHER EARLY IN THE WEEKEND...POTENTIAL OF SHRA WILL RETURN...PERHAPS AS EARLY AS LATE SAT NIGHT/SUN MORNING. DECENT PCPN AMOUNTS MAY THEN BE IN THE OFFING FOR MON/MON NIGHT AS LOW PRES LIFTS INTO THE UPPER MISSISSIPPI VALLEY. ONCE THE UPPER TROF REACHES THE WRN GREAT LAKES...THERE MAY BE A DAY OR 2 OF LIGHT SHOWERY PCPN AT TIMES IN THE MID WEEK PERIOD (PERHAPS EVEN A LITTLE SNOW MIXED IN). AS FOR TEMPS...READINGS OVER THE WEEKEND SHOULD BE CLOSE TO NORMAL... THOUGH IT WILL OBVIOUSLY BE COOL WHERE WINDS ARE ONSHORE NEAR THE GREAT LAKES. TEMPS WILL BEGIN TO TAKE A DOWNWARD TURN MON/TUE WITH THE EARLY WEEK LOW PRES SYSTEM...AND TEMPS WED/THU WILL LIKELY BE QUITE CHILLY/WELL BLO NORMAL FOR MID MAY AS UPPER TROF DRIFTS ACROSS THE AREA (850MB TEMPS FALL TO PERHAPS AS LOW AS -4 TO -6C). FARTHER DOWN THE ROAD...PATTERN WILL PROBABALY CONTINUE TO LEAN TOWARD MAINTAINING OVERALL BLO NORMAL TEMPS OUT TO 10-14 DAYS. BEGINNING SAT...LOW CLOUDS AND POSSIBLY SOME -SHRA/SPRINKLES/-DZ WILL LINGER EARLY OVER THE E. OTHERWISE...EXPECT ABUNDANT SUNSHINE OVER THE W TO SPREAD TO THE ERN FCST AREA BY AFTN AS FCST SOUNDINGS SHOW A DEEP DRY AIR MASS SPREADING OVER THE AREA. DRY AIR MASS WILL ALLOW FOR DEEP MIXING. MIXING UPWARDS OF 750MB ON FCST SOUNDINGS YIELDS MAX TEMPS INTO THE MID TO PERHAPS UPPER 60S IN THE INTERIOR. TEMPS WILL BE COOLEST ALONG LAKE SUPERIOR IN LOCATIONS WHERE WESTERLY WINDS HAVE AN OVERLAKE COMPONENT. LAKE BREEZE MAY DEVELOP NEAR LAKE MICHIGAN IN THE LATTER PART OF THE AFTN. WITH THE DEEP DRY AIR MASS...RH WILL LIKELY TUMBLE TO AS LOW AS AROUND 20PCT IN THE INTERIOR...IN PARTICULAR TOWARD THE WI BORDER. OUT AHEAD OF THE MAIN SYSTEM DIVING TOWARD THE SRN ROCKIES...A LEAD SHORTWAVE WILL SHIFT FROM THE WRN PLAINS SAT MORNING TO THE UPPER LAKES SUN MORNING. GIVEN THAT THE SHORTWAVE WILL BE HEADING INTO THE LARGE SCALE BUILDING UPPER RIDGE DOWNSTREAM OF THE MAIN TROF AMPLIFYING OVER THE ROCKIES...PCPN ASSOCIATED WITH SHORTWAVE WILL LIKELY BE DIMINISHING AS IT MOVES INTO THE UPPER LAKES. ANTECEDENT VERY DRY AIR MASS WILL FURTHER AID THE DIMINISHING OF PCPN SPREADING INTO THE AREA LATE SAT NIGHT/SUN MORNING. QUESTION WILL BE HOW FAST DOES THE PCPN DECAY. AT THIS POINT...IT APPEARS THE GFS IS MUCH TOO AGGRESSIVE WITH WIDESPREAD PCPN IT MOVES ACROSS THE FCST AREA WITH AS MUCH AS 0.25-0.40 INCHES OVER ROUGHLY THE NW HALF OF UPPER MI. OTHER GUIDANCE IS DRIER WITH PCPN DRYING UP AS IT MOVES INTO/ACROSS THE THE FCST AREA. THE NAM IN PARTICULAR HAS ALMOST NO PCPN REACHING UPPER MI. WILL FAVOR THE DRIER SOLUTIONS GIVEN BUILDING UPPER RIDGE AND ANTECEDENT DRY AIR MASS. ONLY CHC POPS WILL BE UTILIZED LATE SAT NIGHT THRU SUN MORNING WITH POPS LOWEST OVER THE NE. CLOUD COVER/PCPN WILL HAVE AN IMPACT ON HIGH TEMPS SUN. IN FAVORING THE DRIER SOLUTIONS...WILL ALSO LEAN TOWARD THE WARMER GUIDANCE FOR HIGHS SUN. AWAY FROM LAKE MODERATION...TEMPS SHOULD REACH WELL INTO THE 60S TO NEAR 70F. MAIN SHORTWAVE MOVES OUT ACROSS THE SRN PLAINS MON MORNING AND LIFTS INTO THE UPPER MISSISSIPPI VALLEY MON NIGHT/TUE ALONG WITH ASSOCIATED SFC LOW PRES. THERE IS CONSIDERABLE MODEL SPREAD ON TIMING SYSTEM WITH SOME HINTS OF A SLOWER TREND DEVELOPING. THE UKMET IS SLOWEST...SHOWING LOW PRES ONLY IN WCNTRL WI AT 00Z WED. NEXT IS THE GEM...SWINGING FROPA THRU UPPER MI TUE AFTN-TUE NIGHT. THE ECMWF BRINGS FRONT THRU MON NIGHT/TUE MORNING WHILE THE GFS IS QUICKEST...PUSHING FRONT ACROSS THE AREA MON EVENING. CONSENSUS OF RECENT RUNS WILL BE UTILIZED GIVEN SPREAD. AT THIS TIME...BEST CHANCE OF SHRA SOME TSRA APPEARS TO BE MON/MON NIGHT...BUT IF SLOWER TREND GAINS MOMENTUM...TIMING WILL NEED TO BE PUSHED BACK A BIT. AS UPPER TROF DRIFTS ACROSS THE WRN LAKES WED/THU...THERMAL TROF WITH 850MB TEMPS IN THE -2 TO -6C RANGE WILL YIELD ABUNDANT CLOUD COVER...ESPECIALLY DURING THE DAYLIGHT HRS. HIGH SUN ANGLE (ONLY 5 1/2 WEEKS TO THE SUMMER SOLSTICE DURING THE MIDDLE OF NEXT WEEK) WILL PROBABLY SUPPORT AT LEAST SCT -SHRA ACTIVITY...PEAKING IN THE AFTN HRS. GIVEN THE COLD TEMPS IN THE COLUMN...MAY SEE SOME GRAUPLE...AND PERHAPS EVEN SOME SNOWFLAKES IF PCPN LINGERS INTO THE NIGHT. IF WED OR THU ENDS UP MAINLY CLOUDY WITH NMRS -SRHA...HIGH TEMPS MAY STRUGGLE TO GET INTO THE 50S INLAND WHILE DAYTIME TEMPS MAY HOLD TO THE MID 30S TO MID 40S NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 139 PM EDT FRI MAY 9 2014 LOW PRESSURE TRACKING JUST NE OF UPPER MI WILL BRING A COLD FRONT WEST TO EAST ACROSS ALL SITES THIS AFTERNOON AND EVENING. ABUNDANT LOW-LEVEL MOISTURE AND UPSLOPE FLOW SHOULD RESULT IN IFR CIGS AT CMX AND IWD OVERNIGHT ALONG WITH -SHRA. DOWNSLOPE FLOW WILL LIMIT SAW TO MVFR CIGS. EXPECT ALL SITES TO BECOME VFR WITH CLEAR SKIES BY SAT MORNING AS DRY AIR PUSHES ACROSS THE AREA. DECENT MIXING AND STRONGER WINDS ALOFT WILL BRING GUSTY WINDS TO ALL SITES INTO SAT...ESPECIALLY FOR CMX...WHERE GUSTS OVER 30KTS WILL BE POSSIBLE LATE THIS EVENING THROUGH THE OVERNIGHT HOURS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 422 AM EDT FRI MAY 9 2014 A LOW PRESSURE SYSTEM NEAR DULUTH EARLY THIS MORNING WILL SLIDE NORTHEAST INTO ONTARIO TODAY. AS THIS OCCURS...WINDS WILL SHIFT AROUND TO THE SOUTHWESTERLY DIRECTION TODAY AND THEN TO THE WEST TONIGHT. EXPECT THE WINDS TO INCREASE FROM WEST TO EAST TODAY AND GENERALLY TO 25KTS TONIGHT...ALTHOUGH THERE COULD BE SOME GUSTS TO 30KTS OVER THE CENTRAL LAKE. THESE STRONGER WINDS...COMBINED WITH GRADUALLY DRYING LOWER LEVELS SHOULD LEAD TO A DIMINISHMENT OF THE DENSE FOG OVER LAKE SUPERIOR FROM SOUTHWEST TO NORTHEAST TODAY. OPTED TO EXTENDED THE DENSE FOG ADVISORY FOR LAKE SUPERIOR INTO THE AFTERNOON HOURS TO BETTER MATCH UP WITH THE INCREASING WINDS AND DRIER AIR. A HIGH PRESSURE RIDGE WILL THEN SLIDE OVER THE AREA ON SATURDAY AND LEAD TO WINDS FALLING BELOW 15KTS SATURDAY NIGHT. THESE LIGHT WINDS WILL REMAIN THROUGH SUNDAY EVENING. A LOW PRESSURE SYSTEM MOVING TOWARDS THE UPPER GREAT LAKES REGION FROM THE CENTRAL PLAINS ON SUNDAY NIGHT WILL LEAD TO INCREASING EASTERLY WINDS (TO 25KTS BY MONDAY EVENING). THEN AS THE LOW SHIFTS NORTHEAST INTO ONTARIO ON TUESDAY...WINDS WILL SHIFT TO THE SOUTHWEST AND STAY BELOW 20KTS. && .HYDROLOGY... ISSUED AT 456 AM EDT FRI MAY 9 2014 THE RAIN SHOWERS AND THUNDERSTORMS PRODUCING HEAVY RAIN HAVE NEARLY DEPARTED UPPER MICHIGAN EARLY THIS MORNING. BUT THEY HAVE LEFT RISING RIVER LEVELS IN THEIR WAKE...ESPECIALLY OVER WESTERN UPPER MICHIGAN WHERE THE HEAVIEST RAIN HAS FALLEN. THE KEWEENAW PENINSULA HAS SEEN AROUND 0.75 INCHES OVERNIGHT IN ADDITION TO THE INCH OF RAIN THAT FELL LAST NIGHT. THIS AS LED TO ANOTHER RISE OF THE TRAP ROCK RIVER OVER THE LAST COUPLE OF HOURS. IT HAS LEVELED OUT SOMEWHAT OVER THE LAST HOUR...BUT WITH A COUPLE HOURS LEFT OF RAIN AND SNOW MELT CONTINUING WOULD EXPECT A LITTLE MORE RISE THIS MORNING. IT DID BRIEFLY REACH 10.15FT...WHICH PUTS THE CURRENT CREST AT THE 4TH HIGHEST ON RECORD. WARM TEMPERATURES TODAY WILL CONTINUE THE MELTING FROM A FEW INCHES OF SNOW WATER EQUIVALENT SHOWN FROM NOHRSC MODEL FROM THE TIP OF THE KEWEENAW PENINSULA THROUGH PAINESDALE...DONKEN...AND WINONA. THIS LINES UP WELL WITH THE LATEST SNOW DEPTHS REPORTED AT PAINESDALE AND HERMAN. WILL SEE HOW THIS SNOW MELT /WARMER FCST TEMPS FOR THE REST OF THIS WEEK/ IMPACT DOWNSTREAM RIVERS INCLUDING THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES AND THE TRAP ROCK RIVER. MOST IF NOT ALL OF THE SNOW COULD MELT BY THIS WEEKEND...BUT IT WILL KEEP THE RIVER LEVELS HIGH INTO EARLY NEXT WEEK. IN ADDITION...WIDESPREAD RAIN IS EXPECTED AGAIN ON MONDAY AND THE CURRENT FORECAST CALLS FOR AROUND A HALF AN INCH OF ACCUMULATION. THOSE LIVING AROUND RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ248-250. && $$ SHORT TERM...SRF LONG TERM...ROLFSON AVIATION...KLUBER MARINE...SRF HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1248 PM CDT FRI MAY 9 2014 .UPDATE... ISSUED AT CDT FRI MAY 9 2014 THE FOCUS FOR THIS UPDATE WAS THE DENSE FOG OVER WESTERN LAKE SUPERIOR AND AREAS ALONG THE NORTH AND SOUTH SHORE...AS WELL AS THE RAIN SHOWERS FOR TODAY AND THIS EVENING. THE MODELS ARE SUGGESTING THE FOG WILL LINGER ALONG THE NORTH SHORE LONGEST...PROBABLY TILL MID AFTERNOON...SO I EXTENDED THE DENSE FOG ADVISORY FOR THE NORTH SHORE UNTIL 3 PM. THE HRRR SEEMED TO BE DOING FAIRLY WELL WITH THE CURRENT COVERAGE OF DENSE FOG...SO I LEANED ON THE HRRR FOR THE AFTERNOON FORECAST. THE FOG NEAR THE TWIN PORTS SHOULD BEGIN TO LIFT VERY LATE THIS MORNING...SO I ONLY EXTENDED THAT PART OF THE ADVISORY TILL NOON. THE NORTHWEST WINDS DEVELOPING BEHIND THE PASSING LOW PRESSURE SYSTEM WILL ALSO BE HELPING TO DISSIPATE THE FOG. WE MAY HAVE HAD PCPN ENDING TOO QUICKLY...AND DID NOT HAVE HIGH ENOUGH PCPN CHANCES ACROSS THE NORTHERN FORECAST AREA. THE MODELS ARE IN GOOD AGREEMENT WITH THE PCPN LINGERING LONGER THAN THE PREVIOUS FORECAST...SO I DELAYED ITS DISSIPATION AND/OR EXIT FROM THE FORECAST AREA THROUGH THIS EVENING. UPDATE ISSUED AT 620 AM CDT FRI MAY 9 2014 UPDATED FOR AVIATION DISCUSSION. && .SYNOPSIS... ISSUED AT 354 AM CDT FRI MAY 9 2014 SURFACE LOW CURRENTLY JUST NORTHEAST OF KSTL IS GRADUALLY MOVING NORTHEAST...WITH SOME FAIRLY STRONG PRESSURE FALLS AND AN INVERTED TROUGH OVER THE ARROWHEAD THIS MORNING. EXTENDING FROM CENTRAL WISCONSIN UP OVER WESTERN UPPER MICHIGAN AND LAKE SUPERIOR IS A BAND OF SHOWERS AND THUNDERSTORMS THAT MOVED OVER THE FORECAST AREA OVERNIGHT. OVER WESTERN MINNESOTA...EASTERN NORTH AND SOUTH DAKOTA IS AN AREA OF RAIN SHOWERS IN THE WRAP AROUND PORTION OF THE STORM...ACCOMPANIED BY A NICE PV ANOMALY INDICATIVE OF A TROWAL. THE SURFACE WARM FRONT EXTENDS EAST FROM THE SURFACE LOW ALONG THE DEWPOINT DISCONTINUITY OVER NORTHERN WISCONSIN AND INTO UPPER MICHIGAN. THE COLD FRONT EXTENDS SOUTH FROM THE LOW...AND IS PLOWING EAST ACROSS IOWA AND MISSOURI. IN THE CONVERGENT AREA AHEAD OF THE SURFACE LOW WHERE WINDS ARE LIGHT AND DEWPOINT DEPRESSIONS ARE LOW...AREAS OF FOG HAVE DEVELOPED. IT SEEMS MOST WIDESPREAD WHERE SOME OF THE COOLER MARINE LAYER HAS SLOPPED ASHORE IN THE LIGHT NORTHEAST FLOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 354 AM CDT FRI MAY 9 2014 THE SURFACE LOW WILL CONTINUE TO MOVE NORTHEAST TODAY...EXITING TO CENTRAL ONTARIO BY 18Z TODAY. THE AREAS OF DENSE FOG MENTIONED ABOVE HAVE BEEN PERSISTENT MOST OF THE NIGHT AHEAD OF THE LOW...AND HAVE DECIDED TO ISSUE A DENSE FOG FOR THE NORTH SHORE AND AREAS AROUND THE HEAD OF THE LAKE UNTIL MID MORNING. AS THE SURFACE LOW MOVES ACROSS THE AREA THE WIND DIRECTION WILL TURN AROUND TO THE NORTHWEST...SOME DRIER AIR WILL BEGIN TO WORK INTO THE AREA EVEN IF TEMPERATURES DONT CHANGE MUCH...SO EXPECT THE FOG TO DISSIPATE BY MID MORNING. THE SHOWERS THIS MORNING OVER THE FAR NORTHEASTERN CWA SHOULD MOVE OFF TO THE EAST...LEAVING THAT PART OF THE FORECAST AREA MOSTLY DRY. THE AREA OF SHOWERS ASSOCIATED WITH THE TROWAL ARE GOING TO SWEEP ACROSS THE FORECAST AREA TODAY AND EARLY THIS EVENING...MAINLY OVER NORTHERN MINNESOTA. AM FAIRLY CONFIDENT IN THIS AREA OF PRECIPITATION...SO HAVE RAISED POPS SOMEWHAT AND REFINED TIMING SOMEWHAT. UNDER THIS AREA OF SHOWERS TEMPERATURES ARE GOING TO ONLY GET INTO THE UPPER 40S TO AROUND 50...WITH HIGHS IN THE MID TO UPPER 50S MOST OTHER LOCATIONS. TEMPERATURES EARLY THIS MORNING ARE IN THE UPPER 50S TO LOWER 60S OVER PORTIONS OF NORTHWEST WISCONSIN WHERE THEY ARE IN THE WARM SECTOR. EXPECT THAT THEY ARE AT OR NEAR THEIR HIGHS FOR TODAY...AND WILL ONLY REMAIN STEADY OR SLOWLY FALL THE REST OF THE DAY. TONIGHT THE SHOWERS WILL STILL BE AFFECTING THE ARROWHEAD REGION IN THE EVENING...BUT A THERE WILL BE A GRADUAL CLEARING TREND SETTING UP FROM SOUTHWEST TO NORTHEAST AS THE STORM GRADUALLY MOVES OFF TO THE NORTHEAST TONIGHT. EXPECT TEMPERATURES TO FALL OFF INTO THE MID 30S MOST LOCATIONS...AS I EXPECT CLEARING TO OCCUR FOR NEARLY THE WHOLE CWA BY EARLY MORNING. WINDS WILL DROP OFF ENOUGH FOR RADIATIONAL COOLING TO BE FAIRLY SIGNIFICANT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 354 AM CDT FRI MAY 9 2014 A NARROW RIDGE OF HIGH PRESSURE ALOFT AND AT THE SURFACE WILL BUILD IN SAT MORNING WITH DRY CONDITIONS AND MOSTLY SUNNY SKIES THROUGH MOST OF THE DAY. A WEAK UPPER S/W AND ASSOCIATED SFC TROUGH WILL LIFT E/NEWD FROM THE DAKOTAS INTO MN AND WRN LAKE SUPERIOR LATER IN THE DAY SATURDAY AND ESPECIALLY SAT NIGHT. THIS SYSTEM WILL PRODUCE ANOTHER ROUND OF WIDESPREAD RAIN SHOWERS AND A FEW WEAK THUNDERSTORMS. THE SFC BOUNDARY WILL STALL OUT AS IT LIFTS NWD INTO NRN MN AND AWAIT THE NEXT SURGE OF WARM MOIST AIR LATE IN THE WEEKEND...ALONG WITH THE NEXT LOW PRESSURE SYSTEM EXPECTED TO TRACK SW TO NE OVER THE UPPER MIDWEST MON INTO TUE MORNING. THIS SYSTEM WILL ONCE AGAIN BE LOADED WITH MOISTURE AND ALSO DRAW UP A SLIGHTLY UNSTABLE AIR MASS TO PRODUCE ISOLATED THUNDERSTORMS AND THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. AS THE SFC LOW APPROACHES FROM THE SW...PRESSURE FALLS WILL INDUCE A STRONG NE FLOW OFF LAKE SUPERIOR AND COMBINE WITH FAIRLY STRONG WAA IN THE MID/LOW LVLS TO PRODUCE ANOTHER PERIOD OF COOL/CLOUDY/FOGGY CONDITIONS AROUND THE PERIPHERY OF THE LAKE. THE PRESENCE OF THIS COOL/STABLE NEAR-SFC LAYER WILL KEEP ANY STORMS ELEVATED THAT TRACK TO THE NORTH...KEEPING THE THREAT OF STRONG/SEVERE WX ON THE LOW SIDE. AN UNSEASONABLY COLD AIR MASS WILL ADVECT IN ON THE BACK SIDE OF THIS SYSTEM AS IT DEPARTS TO THE EAST LATE TUE AND WED. THE AIR PUSHING IN FROM THE NW COULD BE COLD ENOUGH TO ALLOW FOR A FEW LIGHT SNOW SHOWERS TO MIX IN LATE TUE NIGHT...AND AGAIN LATE WED NIGHT. 850MB TEMPS WILL BE ROUGHLY -5 TO -10 DEG C. YES IT IS ALMOST THE MIDDLE OF MAY. WILL SEE SLIGHT IMPROVEMENT INTO THURSDAY AS HIGH PRESSURE GRADUALLY BUILDS IN ACROSS THE MIDWEST. HOWEVER IT WILL NOT BE UNTIL THE WEEKEND UNTIL TEMPS REACH BACK TO NEAR NORMAL. TEMPERATURES THIS WEEKEND WILL BE AT OR SLIGHTLY ABOVE NORMAL WITH LIGHT AND VARIABLE WINDS. SATURDAY WILL LIKELY BE THE MOST PLEASANT DAY WITH DRY CONDITIONS EXPECTED. THE TEMP TREND WILL BEGIN A DOWNWARD SLIDE MON THROUGH WED WITH HIGHS IN THE 40S AND 50S AND OVERNIGHT LOWS IN THE 30S. A GRADUAL WARMING TREND WILL NOT BE FELT UNTIL THE LATTER HALF OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1248 PM CDT FRI MAY 9 2014 A MIX OF IFR/LOW END MVFR CONDITIONS COVERED THE NORTHLAND THIS AFTERNOON. AREAS OF LIGHT RAIN OR DRIZZLE WERE ALSO OCCURRING. THE AREA OF LOW PRESSURE THAT HAS IMPACTED THE REGION FOR THE PAST COUPLE DAYS WILL CONTINUE TO MOVE OFF...AND CONDITIONS WILL GRADUALLY IMPROVE FROM WEST TO EAST. CEILINGS WILL CLEAR FROM WEST TO EAST LATE THIS AFTERNOON INTO THE LATE EVENING HOURS. GUSTY WEST TO NORTHWEST WINDS WILL DEVELOP...THEN DIMINISH THIS EVENING AS THE GRADIENT WEAKENS. && .PRELIMINARY POINT TEMPS/POPS... DLH 51 38 63 48 / 60 40 10 60 INL 50 34 67 44 / 80 40 0 50 BRD 55 36 64 46 / 70 10 40 50 HYR 57 38 67 47 / 70 30 10 60 ASX 59 38 64 45 / 40 40 0 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...DENSE FOG ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR MNZ020-021. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 AM CDT SATURDAY FOR LSZ143>147. DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ140-141. && $$ UPDATE...GROCHOCINSKI SYNOPSIS...LE SHORT TERM...LE LONG TERM...BJT AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1215 PM CDT FRI MAY 9 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT FRI MAY 9 2014 RAP ANALYZED SURFACE LOW JUST SOUTH OF DULUTH EARLY THIS MORNING. AREAS WEST OF THE METRO HAVE SEEN THE WINDS TURN WESTERLY AND PICK UP IN INTENSITY. COLD AIR ADVECTION IS ONGOING IN THESE AREAS...AND WILL CONTINUE TO SPREAD ACROSS THE REMAINDER OF THE FORECAST AREA TODAY. THE SURFACE LOW WILL SLOWLY CONTINUE NORTHEASTWARD...AS THE WESTERLY WINDS TAKE MUCH OF THE DAY TO SPREAD ACROSS WEST CENTRAL WISCONSIN. ABUNDANT LOW LEVEL MOISTURE WILL ALLOW FOR LOW LCL HEIGHTS WHICH IS CURRENTLY NOTICEABLE IN THE OBSERVATIONS BEHIND THE COLD FRONT WHERE CEILINGS UNDER 1K FEET ARE PRESENT. RAP AND NAM MODEL SOUNDINGS INDICATE THIS MOISTURE STICKING AROUND FOR MUCH OF THE DAY...SO TRENDED TOWARD A MORE PESSIMISTIC SKY COVER FORECAST AND HENCE LOWERED MAX TEMPERATURES TODAY BY A FEW DEGREES ACROSS THE FA. MAX TEMPS WILL BE ABOUT 10 DEGREES BELOW SEASONAL NORMALS FOR THIS TIME OF YEAR. IN ADDITION...WRAP AROUND LIGHT RAIN SHOWERS ARE EXPECTED TO MOVE ACROSS THE NORTHERN PORTION OF THE CWA AS THEY CYCLONIC CIRCULATION ALOFT REMAINS BETTER TOWARD THE NORTH /AS WELL AS AT LEAST SOME FGEN AND FN VECTOR CONVERGENCE/. SKIES WILL BEGIN CLEARING LATE THIS AFTERNOON AND MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT...EXCEPT CLOUDS WILL QUICKLY BEGIN FILLING IN FROM THE SOUTHWEST EARLY SATURDAY MORNING. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 340 AM CDT FRI MAY 9 2014 AN UNSETTLED PERIOD REMAINS FORECAST FOR MUCH OF THE LONGER TERM AS NORTHERN AND SOUTHERN STREAM ENERGY EVENTUALLY PHASE OVER THE CENTER OF THE COUNTRY AROUND THE MIDDLE OF NEXT WEEK. THIS PROCESS OCCURS THE FASTEST WITH THE GFS WHILE DP/DT SHOWS THAT THE SLOWER ECMWF IS BECOMING EVEN SLOWER WITH TIME. ON SATURDAY...A WAVE MOVING IN FROM THE CENTRAL PLAINS WILL BRING THICKENING CLOUDINESS AND SHOWERS BACK ACROSS THE FA FROM SW TO NE DURING THE DAY. A BRIEF BREAK IN THE PRECIPITATION IS EXPECTED SATURDAY NIGHT BEFORE A MORE POTENT WAVE BEGINS TO TAKE SHAPE OVER THE CENTRAL PLAINS ON SUNDAY. THIS WAVE IS BEING DRIVEN BY THE SOUTHERN STREAM ENERGY. USING THE SLOWER ECWMF...THE LOW IN THE PLAINS TAKES UNTIL MONDAY EVENING TO ARRIVE IN SE MN. THIS PLACES MUCH OF THE FA IN LOW LEVEL THETA-E ADVECTION FROM SUNDAY THROUGH MONDAY...WITH SOUTHERN MN BEARING THE BRUNT OF IT. HENCE...LIKELY POPS STREAM BACK IN ON SUNDAY FROM THE SOUTHWEST AND PERSIST THROUGH MONDAY. WIDESPREAD HALF INCH TO ONE INCH RAINFALL IS LIKELY DURING THIS PERIOD WITH SOME TWO INCH AMOUNTS OVER SOUTHERN MN. THERE WILL CERTAINLY BE THE THREAT FOR SOME THUNDERSTORMS...ESPECIALLY ON MONDAY FROM THE TWIN CITIES ON EAST AND SOUTH. STRICTLY USING THE ECMWF TIMING WOULD INDICATE A WINDOW OF OPPORTUNITY FOR STRONG TO SEVERE STORMS MONDAY AFTERNOON/EVENING TO THE SOUTH AND EAST OF THE TWIN CITIES. THE SHOWERS WILL BEGIN TO TAPER OFF MONDAY NIGHT AS THE LOW PRESSURE SYSTEM MOVES NORTHEAST OF THE FA. INSTABILITY SHOWERS ARE POSSIBLE MAINLY FROM CENTRAL MINNESOTA ON NORTHWARD ON TUESDAY. SCATTERED SHOWERS ARE BACK FOR MUCH OF THE FA WEDNESDAY AND THURSDAY AS THE UPPER TROUGH COMES TOGETHER FROM THE UPPER MISSISSIPPI VALLEY TO THE GULF COAST. HIGH TEMPERATURES WILL BE CLOSE TO NORMAL THIS WEEKEND...BUT THEN RETREAT TO SOME 10 TO 15 DEGREES BELOW NORMAL FOR THE MIDDLE TO END OF NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1204 PM CDT FRI MAY 9 2014 MVFR CIGS REMAIN OVER PARTS MUCH OF THE CENTRAL AND EAST INTO THE AFTERNOON. GRADUALLY BECOMING VFR AND SKC FROM WEST TO EAST AS THE UPPER TROUGH MOVES EAST. SOME CHANCE OF -SHRA OVER THE NORTHEAST CWA INTO THE AFTERNOON AS WELL. EXPECT WEST TO NORTHWEST WINDS 13-17KTS WITH GUSTS TO 25-29KTS OVER THE AREA INTO THE AFTERNOON...BEFORE DIMINISHING FROM WEST TO EAST BY EVENING. LIGHTER WINDS OVERNIGHT AS SURFACE HIGH MOVES THROUGH....BECOMING SOUTHEAST INTO SATURDAY AND INCREASING AHEAD OF NEXT TROUGH. SHOULD SEE SOME MID/HIGH LEVEL CLOUDS INCREASE AGAIN OVER THE WESTERN AREA LATER TONIGHT AND SATURDAY MORNING...BUT REMAINING VFR. COULD SEE SOME -SHRA MOVE IN TOWARDS KRWF 15Z-18Z BUT CONFIDENCE IS LOW ON HOW FAST MOISTURE WILL RETURN AND SATURATE. KEPT IT DRY FOR NOW. KMSP...CIGS LIFTING TO MVFR LATE AFTERNOON. CLEARING BY EARLY EVENING AS UPPER TROUGH EXITS EAST. SURFACE HIGH MOVES OVER THE AREA TONIGHT WITH LIGHT WINDS BECOMING SOUTHEAST AND INCREASING SATURDAY MORNING. MID/HIGH LEVEL CLOUDS SPREAD EAST SATURDAY MORNING WITH SOME CHANCE OF -SHRA IN THE AFTERNOON. LEFT IT AS VCSH FOR NOW...AS SOUTHEAST FLOW WILL BE DRY INITIALLY. /OUTLOOK FOR KMSP/ SAT NITE...VFR. CHC -SHRA/-TSRA. WINDS SSE 10KTS. SUN...MVFR POSSIBLE. LIKELY -SHRA. WINDS SW TO NW 10-15 KTS. MON...MVFR POSSIBLE. LIKELY -SHRA. WINDS NW 10KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...SPD LONG TERM...RAH AVIATION...DWE
AREA FORECAST DISCUSSION
NWS HASTINGS NE
554 PM CDT FRI MAY 9 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 252 PM CDT FRI MAY 9 2014 MAIN FORECAST CONCERNS WILL BE CHANCE FOR SPRINKLES AND LATE TONIGHT AND INTO SATURDAY MORNING AND TEMPERATURES THROUGH THE PERIOD. A WEAK SURFACE HIGH PRESSURE SYSTEM IS DRIFTING THROUGH THE CENTRAL PLAINS TODAY. THIS HAS KEPT SKIES MOSTLY CLEAR AND WINDS FAIRLY LIGHT AND VARIABLE. THE SURFACE HIGH IS EXPECTED TO SLIDE TO THE SOUTHEAST LATE THIS AFTERNOON AND THIS EVENING. WINDS WILL CONTINUE TO TURN TO THE SOUTHWEST OR WEST THROUGH THE EVENING HOURS. AN UPPER LEVEL WAVE WILL MOVE INTO THE AREA TONIGHT. SO FAR THE LOWER LAYERS ARE FAIRLY DRY...BUT BOTH THE GFS AND NAM BRING IN SOME SPOTTY PRECIPITATION TONIGHT AND THE HRRR AND WRF ALSO HINT AS SOMETHING VERY SPOTTY ACROSS THE AREA. WITH THE DRY LOWER LEVELS HAVE KEPT A FEW SPRINKLES MAINLY IN THE NORTHERN PART OF THE FORECAST AREA BECAUSE CONFIDENCE IS LOW THERE WOULD BE ANYTHING MEASURABLE. A WEAK COLD FRONT WILL MOVE INTO THE AREA LATE TONIGHT...MOVING THROUGH THE AREA SATURDAY MORNING. FOR A FEW HOURS BEHIND THE FRONT THERE WILL BE A LITTLE BREEZIER CONDITIONS...BUT BEFORE MID AFTERNOON THE WINDS START TO DIMINISH A LITTLE. EVEN BEHIND THE COLD FRONT THE TEMPERATURES ON SATURDAY WILL BE FAIRLY WARM. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 252 PM CDT FRI MAY 9 2014 GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST QUASI- ZONAL UPPER TROPOSPHERIC FLOW WILL EXIST ACROSS MUCH OF THE CONUS AT 00Z SUNDAY...ALTHOUGH A STRENGTHENING UPPER TROPOSPHERIC SHORT WAVE OVER THE SOUTHWESTERN CONUS WILL BEGIN TURNING THE FLOW OVER OUR AREA MORE SOUTHWESTERLY BY 12Z SUNDAY. EVENTUALLY AN UPPER TROPOSPHERIC LONGWAVE TROUGH AXIS IS EXPECTED TO DEVELOP FROM SOUTH CENTRAL CANADA INTO THE SOUTHWESTERN CONUS BY 00Z MONDAY...WITH THE TROUGH AXIS EXPECTED TO MOVE EAST ACROSS ACROSS OUR AREA MONDAY NIGHT INTO TUESDAY...RESULTING IN NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA TUESDAY NIGHT ONWARD. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS EXPECTED ACROSS WESTERN KANSAS AND EASTERN COLORADO AT 00Z SUNDAY. THIS SURFACE LOW IS EXPECTED TO MOVE NORTHEAST...LIKELY NEARING NORTHEAST KANSAS BY 00Z MONDAY AND THE UPPER MISSISSIPPI VALLEY BY 00Z TUESDAY. SO ALTHOUGH THE LOWER TROPOSPHERIC FLOW ACROSS OUR AREA WILL START THE LONG TERM FORECAST PERIOD FROM THE EAST/SOUTHEAST...A TRANSITION TO THE NORTHEAST IS EXPECTED ACROSS MUCH OF THE AREA DURING THE DAY SUNDAY...AND TO THE NORTHWEST SUNDAY NIGHT THROUGH MUCH OF THE REST OF THE LONG TERM FORECAST PERIOD. THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST A 50-60KT JET STREAK JUST ABOVE THE BOUNDARY LAYER WILL PROMOTE ENOUGH THERMAL ADVECTION FOR PRECIPITATION PRODUCTION ACROSS MUCH OF THE CWA SATURDAY NIGHT ...ESPECIALLY ACROSS EASTERN PORTIONS OF THE CWA WHERE THERMAL ADVECTION...AS WELL AS MOISTURE CONVERGENCE...WILL BE ENHANCED. GIVEN THIS...WENT AHEAD WITH 20-70% POPS ACROSS MUCH OF THE CWA SATURDAY NIGHT...WITH THE HIGHEST POPS RELEGATED ACROSS OUR EAST. AT THIS TIME ANY CONVECTION THAT IS REALIZED SATURDAY NIGHT IS EXPECTED TO REMAIN WEAK. ANY OVERNIGHT CONVECTION SHOULD DEPART TO THE EAST/NORTHEAST BY DAYBREAK SUNDAY AS THE LOWER TROPOSPHERIC JET STREAK ALSO SHIFTS TO THE EAST. THIS MAY ALLOW FOR A BREAK IN PRECIPITATION AT SOME POINT SUNDAY MORNING...BUT POPS STILL REMAIN INTACT FOR THE ENTIRE CWA ON SUNDAY AS THERMAL ADVECTION AHEAD OF THE APPROACHING UPPER TROPOSPHERIC TROUGH INCREASES. AS THE AFOREMENTIONED SURFACE LOW MOVES INTO NORTHEASTERN KANSAS SUNDAY AFTERNOON AND EVENING...AN ASSOCIATED LOWER TROPOSPHERIC BAROCLINIC ZONE IS EXPECTED TO BACK NORTHWEST AS A WARM FRONT...PERHAPS PUSHING INTO OUR EXTREME EAST/SOUTHEASTERN CWA. LOWER TROPOSPHERIC CONVERGENCE AND RESULTANT LIFT ALONG THIS BAROCLINIC ZONE...ALONG WITH INCREASING SYNOPTIC- SCALE OMEGA DUE TO INCREASING UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH...APPEARS AS THOUGH THEY WILL BE SUFFICIENT FOR CONVECTIVE INITIATION SUNDAY AFTERNOON AND EVENING. SOME OF THIS CONVECTION COULD CERTAINLY BE REALIZED OVER OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING. THE BAROCLINIC ZONE SHOULD QUICKLY DEPART OUR AREA TO THE EAST/SOUTHEAST SUNDAY EVENING AS THE SURFACE LOW MOVES NORTHEAST...THUS ALLOWING A MUCH COOLER AND DRIER LOWER TROPOSPHERIC AIR MASS INTO THE AREA. THIS WILL RESULT IN RAPIDLY DECREASING POTENTIAL INSTABILITY THUS ELIMINATING ANY CHANCE OF DEEP CONVECTION ACROSS OUR AREA. THAT BEING SAID...CONTINUED THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH APPEARS IT WILL STILL BE SUFFICIENT FOR PRECIPITATION PRODUCTION HEADING INTO THE REMAINDER OF SUNDAY NIGHT AND EVEN MONDAY. AS A RESULT...POPS REMAIN INTACT ACROSS MUCH OF THE CWA SUNDAY NIGHT INTO MONDAY. BY MONDAY NIGHT...UPPER TROPOSPHERIC THERMAL ADVECTION SHOULD DIMINISH AS THE TROUGH AXIS BEGINS CLEARING THE AREA. DRY CONDITIONS ARE CURRENTLY FORECAST MONDAY NIGHT THROUGH WEDNESDAY AS A RESULT. WEDNESDAY NIGHT INTO THURSDAY...THERE ARE INDICATIONS FROM THE OPERATIONAL GFS...AND TO A LESSER EXTENT THE NAM...OF A WEAK UPPER TROPOSPHERIC PERTURBATION MOVING ACROSS THE REGION AND PERHAPS PROVIDING A PERIOD OF LIGHT PRECIPITATION. CONFIDENCE REGARDING THIS FEATURE IS NOT HIGH...BUT ALLBLEND PRESENTED A ~20% POP TO OUR NORTH/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY AND OPTED TO KEEP THIS POP AS IS. GUIDANCE SUGGESTS DEW POINT READINGS WELL INTO THE 60S WILL INFILTRATE MUCH OF EASTERN KANSAS SUNDAY AFTERNOON ON THE WARM SIDE OF THE BAROCLINIC ZONE. THE MOISTURE CONTENT OF THE LOWER TROPOSPHERIC AIR MASS IS NOT EXPECTED TO BE NEARLY AS ROBUST FARTHER NORTHWEST INTO OUR AREA...BUT AGAIN IF THE BAROCLINIC ZONE CAN SNEAK INTO OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING...THEN POTENTIAL INSTABILITY VALUES COULD CERTAINLY CLIMB INTO THE 1000- 2000J/KG RANGE. DEEP LAYER BULK SHEAR VALUES ON THE ORDER OF ~50KTS ARE ALSO FORECAST ACROSS OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING. SO...ALTHOUGH IT APPEARS THE BULK OF THE SEVERE WEATHER SHOULD REMAIN SOUTH AND EAST OF OUR CWA...IT STILL APPEARS THERE WILL BE A BRIEF WINDOW OF OPPORTUNITY FOR STRONG THUNDERSTORM ACTIVITY ACROSS PORTIONS OF OUR CWA...GENERALLY ALONG AND SOUTHEAST OF A LINE FROM ALMA TO YORK. A THREAT FOR SEVERE WEATHER WILL RESIDE FARTHER SOUTHEAST...GENERALLY ALONG AND SOUTHEAST OF A LINE FROM BELOIT TO HEBRON. WILL GO AHEAD AND MENTION THESE THREATS IN THE HWO FOR SUNDAY. GUIDANCE ALSO SUGGESTS LOWER TROPOSPHERIC PRESSURE RISES POST-FROPA COULD PROVIDE A STRONG LOWER TROPOSPHERIC WIND FIELD ACROSS NORTHWESTERN PORTIONS OF THE CWA SUNDAY AFTERNOON INTO SUNDAY EVENING. GUIDANCE SUGGESTS A SUSTAINED WIND OF 25-30KTS WITH LOCALLY HIGHER GUSTS WILL BE REALIZED AND AS A RESULT...WILL MENTION SUCH CONDITIONS IN THE HWO. A COOLER LOWER TROPOSPHERIC AIR MASS WILL INFILTRATE THE AREA FOLLOWING THE PASSAGE OF THE BAROCLINIC ZONE SUNDAY...WITH HIGHS GENERALLY IN THE 50 ON MONDAY AND IN THE 60S TUESDAY THROUGH FRIDAY. OVERNIGHT LOWS IN THE 40S ARE FORECAST FOR THE MOST PART THROUGH THE LONG TERM FORECAST PERIOD. && .AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z SATURDAY EVENING) ISSUED AT 545 PM CDT FRI MAY 9 2014 WIND SHOULD QUICKLY DIMINISH BY THE TIME OF THE BEGINNING OF THE FORECAST. ONLY HIGH LEVEL CIRRUS IS EXPECTED. HOWEVER...THERE IS A VERY OUTSIDE SHOT AT A RANDOM THUNDERSHOWER DEVELOPING AROUND 12Z...BUT THIS WOULD BE A BIT MORE LIKELY FARTHER TO THE EAST. MODELS INDICATE A POTENTIAL BRUSH WITH LOW-LEVEL WIND SHEAR ISSUES NEAR 06Z...BUT THIS APPEARS TO BE JUST LOW ENOUGH NOT TO INCLUDE IN THIS FORECAST. WIND SPEED WILL ONCE AGAIN KICK UP BY AFTERNOON SATURDAY WITH INCREASED LOW-LEVEL LAPSE RATES. && .FIRE WEATHER... ISSUED AT 252 PM CDT FRI MAY 9 2014 RELATIVE HUMIDITY LEVELS ARE EXPECTED TO DROP BELOW 25 PERCENT FOR NORTH CENTRAL KANSAS AND FAR SOUTHERN SOUTH CENTRAL NEBRASKA FOR SATURDAY AFTERNOON. DURING THE MORNING THE WINDS WILL BE WEST OR NORTHWEST AT 15 TO 20 MPH WITH GUSTS TO AROUND 25 MPH...BUT BY AFTERNOON...WHEN THE RELATIVE HUMIDITY WILL BE THE LOWEST...THE WINDS WILL HAVE DIMINISHED TO 10 TO 15 MPH WITH GUSTS TO 20 MPH. EXPECT THERE TO ONLY BE A SMALL TIME FRAME WHERE NEAR CRITICAL FIRE DANGER IS EVEN CLOSE. WILL LEAVE IT OUT OF THE HWO AT THIS TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...BRYANT AVIATION...HEINLEIN FIRE WEATHER...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
320 PM CDT FRI MAY 9 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 252 PM CDT FRI MAY 9 2014 MAIN FORECAST CONCERNS WILL BE CHANCE FOR SPRINKLES AND LATE TONIGHT AND INTO SATURDAY MORNING AND TEMPERATURES THROUGH THE PERIOD. A WEAK SURFACE HIGH PRESSURE SYSTEM IS DRIFTING THROUGH THE CENTRAL PLAINS TODAY. THIS HAS KEPT SKIES MOSTLY CLEAR AND WINDS FAIRLY LIGHT AND VARIABLE. THE SURFACE HIGH IS EXPECTED TO SLIDE TO THE SOUTHEAST LATE THIS AFTERNOON AND THIS EVENING. WINDS WILL CONTINUE TO TURN TO THE SOUTHWEST OR WEST THROUGH THE EVENING HOURS. AN UPPER LEVEL WAVE WILL MOVE INTO THE AREA TONIGHT. SO FAR THE LOWER LAYERS ARE FAIRLY DRY...BUT BOTH THE GFS AND NAM BRING IN SOME SPOTTY PRECIPITATION TONIGHT AND THE HRRR AND WRF ALSO HINT AS SOMETHING VERY SPOTTY ACROSS THE AREA. WITH THE DRY LOWER LEVELS HAVE KEPT A FEW SPRINKLES MAINLY IN THE NORTHERN PART OF THE FORECAST AREA BECAUSE CONFIDENCE IS LOW THERE WOULD BE ANYTHING MEASURABLE. A WEAK COLD FRONT WILL MOVE INTO THE AREA LATE TONIGHT...MOVING THROUGH THE AREA SATURDAY MORNING. FOR A FEW HOURS BEHIND THE FRONT THERE WILL BE A LITTLE BREEZIER CONDITIONS...BUT BEFORE MID AFTERNOON THE WINDS START TO DIMINISH A LITTLE. EVEN BEHIND THE COLD FRONT THE TEMPERATURES ON SATURDAY WILL BE FAIRLY WARM. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 252 PM CDT FRI MAY 9 2014 GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST QUASI- ZONAL UPPER TROPOSPHERIC FLOW WILL EXIST ACROSS MUCH OF THE CONUS AT 00Z SUNDAY...ALTHOUGH A STRENGTHENING UPPER TROPOSPHERIC SHORT WAVE OVER THE SOUTHWESTERN CONUS WILL BEGIN TURNING THE FLOW OVER OUR AREA MORE SOUTHWESTERLY BY 12Z SUNDAY. EVENTUALLY AN UPPER TROPOSPHERIC LONGWAVE TROUGH AXIS IS EXPECTED TO DEVELOP FROM SOUTH CENTRAL CANADA INTO THE SOUTHWESTERN CONUS BY 00Z MONDAY...WITH THE TROUGH AXIS EXPECTED TO MOVE EAST ACROSS ACROSS OUR AREA MONDAY NIGHT INTO TUESDAY...RESULTING IN NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA TUESDAY NIGHT ONWARD. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS EXPECTED ACROSS WESTERN KANSAS AND EASTERN COLORADO AT 00Z SUNDAY. THIS SURFACE LOW IS EXPECTED TO MOVE NORTHEAST...LIKELY NEARING NORTHEAST KANSAS BY 00Z MONDAY AND THE UPPER MISSISSIPPI VALLEY BY 00Z TUESDAY. SO ALTHOUGH THE LOWER TROPOSPHERIC FLOW ACROSS OUR AREA WILL START THE LONG TERM FORECAST PERIOD FROM THE EAST/SOUTHEAST...A TRANSITION TO THE NORTHEAST IS EXPECTED ACROSS MUCH OF THE AREA DURING THE DAY SUNDAY...AND TO THE NORTHWEST SUNDAY NIGHT THROUGH MUCH OF THE REST OF THE LONG TERM FORECAST PERIOD. THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST A 50-60KT JET STREAK JUST ABOVE THE BOUNDARY LAYER WILL PROMOTE ENOUGH THERMAL ADVECTION FOR PRECIPITATION PRODUCTION ACROSS MUCH OF THE CWA SATURDAY NIGHT ...ESPECIALLY ACROSS EASTERN PORTIONS OF THE CWA WHERE THERMAL ADVECTION...AS WELL AS MOISTURE CONVERGENCE...WILL BE ENHANCED. GIVEN THIS...WENT AHEAD WITH 20-70% POPS ACROSS MUCH OF THE CWA SATURDAY NIGHT...WITH THE HIGHEST POPS RELEGATED ACROSS OUR EAST. AT THIS TIME ANY CONVECTION THAT IS REALIZED SATURDAY NIGHT IS EXPECTED TO REMAIN WEAK. ANY OVERNIGHT CONVECTION SHOULD DEPART TO THE EAST/NORTHEAST BY DAYBREAK SUNDAY AS THE LOWER TROPOSPHERIC JET STREAK ALSO SHIFTS TO THE EAST. THIS MAY ALLOW FOR A BREAK IN PRECIPITATION AT SOME POINT SUNDAY MORNING...BUT POPS STILL REMAIN INTACT FOR THE ENTIRE CWA ON SUNDAY AS THERMAL ADVECTION AHEAD OF THE APPROACHING UPPER TROPOSPHERIC TROUGH INCREASES. AS THE AFOREMENTIONED SURFACE LOW MOVES INTO NORTHEASTERN KANSAS SUNDAY AFTERNOON AND EVENING...AN ASSOCIATED LOWER TROPOSPHERIC BAROCLINIC ZONE IS EXPECTED TO BACK NORTHWEST AS A WARM FRONT...PERHAPS PUSHING INTO OUR EXTREME EAST/SOUTHEASTERN CWA. LOWER TROPOSPHERIC CONVERGENCE AND RESULTANT LIFT ALONG THIS BAROCLINIC ZONE...ALONG WITH INCREASING SYNOPTIC- SCALE OMEGA DUE TO INCREASING UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH...APPEARS AS THOUGH THEY WILL BE SUFFICIENT FOR CONVECTIVE INITIATION SUNDAY AFTERNOON AND EVENING. SOME OF THIS CONVECTION COULD CERTAINLY BE REALIZED OVER OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING. THE BAROCLINIC ZONE SHOULD QUICKLY DEPART OUR AREA TO THE EAST/SOUTHEAST SUNDAY EVENING AS THE SURFACE LOW MOVES NORTHEAST...THUS ALLOWING A MUCH COOLER AND DRIER LOWER TROPOSPHERIC AIR MASS INTO THE AREA. THIS WILL RESULT IN RAPIDLY DECREASING POTENTIAL INSTABILITY THUS ELIMINATING ANY CHANCE OF DEEP CONVECTION ACROSS OUR AREA. THAT BEING SAID...CONTINUED THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH APPEARS IT WILL STILL BE SUFFICIENT FOR PRECIPITATION PRODUCTION HEADING INTO THE REMAINDER OF SUNDAY NIGHT AND EVEN MONDAY. AS A RESULT...POPS REMAIN INTACT ACROSS MUCH OF THE CWA SUNDAY NIGHT INTO MONDAY. BY MONDAY NIGHT...UPPER TROPOSPHERIC THERMAL ADVECTION SHOULD DIMINISH AS THE TROUGH AXIS BEGINS CLEARING THE AREA. DRY CONDITIONS ARE CURRENTLY FORECAST MONDAY NIGHT THROUGH WEDNESDAY AS A RESULT. WEDNESDAY NIGHT INTO THURSDAY...THERE ARE INDICATIONS FROM THE OPERATIONAL GFS...AND TO A LESSER EXTENT THE NAM...OF A WEAK UPPER TROPOSPHERIC PERTURBATION MOVING ACROSS THE REGION AND PERHAPS PROVIDING A PERIOD OF LIGHT PRECIPITATION. CONFIDENCE REGARDING THIS FEATURE IS NOT HIGH...BUT ALLBLEND PRESENTED A ~20% POP TO OUR NORTH/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY AND OPTED TO KEEP THIS POP AS IS. GUIDANCE SUGGESTS DEW POINT READINGS WELL INTO THE 60S WILL INFILTRATE MUCH OF EASTERN KANSAS SUNDAY AFTERNOON ON THE WARM SIDE OF THE BAROCLINIC ZONE. THE MOISTURE CONTENT OF THE LOWER TROPOSPHERIC AIR MASS IS NOT EXPECTED TO BE NEARLY AS ROBUST FARTHER NORTHWEST INTO OUR AREA...BUT AGAIN IF THE BAROCLINIC ZONE CAN SNEAK INTO OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING...THEN POTENTIAL INSTABILITY VALUES COULD CERTAINLY CLIMB INTO THE 1000- 2000J/KG RANGE. DEEP LAYER BULK SHEAR VALUES ON THE ORDER OF ~50KTS ARE ALSO FORECAST ACROSS OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING. SO...ALTHOUGH IT APPEARS THE BULK OF THE SEVERE WEATHER SHOULD REMAIN SOUTH AND EAST OF OUR CWA...IT STILL APPEARS THERE WILL BE A BRIEF WINDOW OF OPPORTUNITY FOR STRONG THUNDERSTORM ACTIVITY ACROSS PORTIONS OF OUR CWA...GENERALLY ALONG AND SOUTHEAST OF A LINE FROM ALMA TO YORK. A THREAT FOR SEVERE WEATHER WILL RESIDE FARTHER SOUTHEAST...GENERALLY ALONG AND SOUTHEAST OF A LINE FROM BELOIT TO HEBRON. WILL GO AHEAD AND MENTION THESE THREATS IN THE HWO FOR SUNDAY. GUIDANCE ALSO SUGGESTS LOWER TROPOSPHERIC PRESSURE RISES POST-FROPA COULD PROVIDE A STRONG LOWER TROPOSPHERIC WIND FIELD ACROSS NORTHWESTERN PORTIONS OF THE CWA SUNDAY AFTERNOON INTO SUNDAY EVENING. GUIDANCE SUGGESTS A SUSTAINED WIND OF 25-30KTS WITH LOCALLY HIGHER GUSTS WILL BE REALIZED AND AS A RESULT...WILL MENTION SUCH CONDITIONS IN THE HWO. A COOLER LOWER TROPOSPHERIC AIR MASS WILL INFILTRATE THE AREA FOLLOWING THE PASSAGE OF THE BAROCLINIC ZONE SUNDAY...WITH HIGHS GENERALLY IN THE 50 ON MONDAY AND IN THE 60S TUESDAY THROUGH FRIDAY. OVERNIGHT LOWS IN THE