Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/11/13


AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 PM MST FRI FEB 8 2013 .SYNOPSIS...A PACIFIC STORM SYSTEM WILL BRING COLDER TEMPERATURES WITH RAIN AND SNOW SHOWERS SATURDAY. EXPECT COLD TEMPERATURES WITH A FEW SHOWERS TO START THE NEW WEEK FOLLOWED BY A STRONG WARMING TREND DURING THE MIDDLE OF THE WEEK. && .DISCUSSION...DEEP UPPER LOW PRESSURE SYSTEM OVER THE GREAT BASIN REGION EXTENDING INTO SRN CALIFORNIA AT THIS TIME. IR SATELLITE IMAGERY INDICATES MOSTLY CLEAR SKIES ACROSS MUCH OF PIMA/SE PINAL COUNTIES WITH MOSTLY CLOUDY SKIES ELSEWHERE. 08/21Z RUC HRRR DEPICTS PRECIP TO DEVELOP ACROSS WRN PIMA COUNTY AROUND 05Z-07Z SATURDAY... THEN PRECIP IS PROGGED TO MOVE EWD INTO THE TUCSON METRO AREA AROUND 1030Z-1100Z SATURDAY. THIS TIMING IS SLIGHTLY FASTER VERSUS THE 09/00Z NAM12. HOWEVER...HAVE NOTED A MARKED INCREASE IN POPS VIA THE 09/00Z NAM12 VERSUS PREVIOUS NAM12 SOLUTIONS. BASED ON THE RUC HRRR AND NAM...SEE NO REASON TO MAKE ANY CHANGES TO THE OFFICIAL FORECAST AT THIS TIME. THUS...WILL CONTINUE WITH A WINTER WEATHER ADVISORY FOR ELEVATIONS ABOVE 4000 FEET FROM 5 AM TO 5 PM MST SATURDAY. MUCH COLDER SAT WITH FORECAST HIGH TEMPS TO BE ABOUT 15-20 DEGS LOWER VERSUS TEMPS ACHIEVED THIS AFTERNOON. PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION FOR ADDITIONAL DETAIL. && .PREV DISCUSSION...MID LEVEL DYNAMICS AND COLD AIR FROM STRONG LOW PUSHING INTO ARIZONA TONIGHT AND SATURDAY. MAIN TROUGH INFLECTION WILL COME TOGETHER WITH MOISTURE MAINLY AFTER 12Z SATURDAY FOR OUR PART OF THE STATE WITH A SIGNIFICANT UPSLOPE COMPONENT. 18Z NAMDNG5 AND 12Z ECMWF LOOK SOLID AND CONTINUE TO HANDLE THINGS WELL. LATEST HRRR SHOWING ISOLATED DEVELOPMENT WEST AND NORTHWEST OF TUCSON BETWEEN 04Z-08Z WHICH FITS WELL. SHOWERS INCREASING FROM THE WEST DURING THE DAY SATURDAY. NOT EXCESSIVE STORM TOTAL PRECIP WITH QPF GENERALLY RANGING FROM .15 IN VALLEYS TO .5 IN MOUNTAINS. COLD AIR ALREADY PUSHING IN TONIGHT AND BY THE TIME THE BEST PRECIP GETS HERE AFTER 12Z SNOW LEVELS ARE EXPECTED TO RANGE FROM 3000 TO 4000 FEET ACROSS MOST OF THE AREA. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR SATURDAY ABOVE 4000 FEET...EVEN THOUGH HIGHER ELEVATIONS MAY STRUGGLE TO END UP WITH ENOUGH SNOW TO MEET CRITERIA. THE PRIME AREA OF CONCERN IS 3500 TO 5500 FEET. PLEASE SEE PHXWSWTWC FOR DETAILS. SOME CLEARING SATURDAY NIGHT INTO SUNDAY MORNING WITH SOLID COLD AIR IN PLACE...WITH WIDESPREAD NEAR OR BELOW FREEZING TEMPERATURES AREAS OF FROST ARE A CONCERN. ON MONDAY A REINFORCING SHOT OF COLD AIR WITH A SYSTEM DIGGING DOWN THE BACK SIDE OF THE MEAN TROUGH POSITION FROM THE NORTH. RESIDUAL BOUNDARY LAYER MOISTURE SHOULD GIVE IT ENOUGH TO GENERATE A FEW MORE RAIN AND SNOW SHOWERS ACROSS THE AREA AS SNOW LEVELS REMAIN LOW. OVERALL SATURDAY THROUGH TUESDAY WE EXPECT A SUSTAINED PERIOD OF COLD TEMPERATURES WITH AT LEAST 4 DAYS WHERE TEMPERATURES DON`T CLIMB OUT OF THE 50S. SOME CONCERNS WITH LOW TEMPERATURES...WITH THE POTENTIAL OF A WIDESPREAD FREEZE FROM TUCSON THROUGH THE LOWER DESERTS...AND WIDESPREAD HARD FREEZE AT HIGHER ELEVATION LOCATIONS FROM SUNDAY MORNING THROUGH WEDNESDAY MORNING. && .AVIATION...SCT -SHRA TO DEVELOP WEST OF KTUS 06Z-08Z SATURDAY... THEN SCT-NMRS -SHRA AND HIGHER TERRAIN -SHSN TO MOVE EWD ACROSS SE AZ SATURDAY. BULK OF PRECIP TO END AROUND 10/00Z. BEST CHANCE OF PRECIP FOR KTUS WILL BE BETWEEN 09Z-18Z SATURDAY. OTHERWISE... CLOUD DECKS LOWERING TO GENERALLY 5-9K FT AGL AROUND 08Z-10Z SATURDAY AND CONTINUING INTO SATURDAY AFTERNOON. CLOUDS DECREASING SATURDAY EVENING. SURFACE WIND SWLY/WLY 10-20 KTS WITH GUSTS TO AROUND 30 KTS THRU SATURDAY AFTERNOON FOLLOWED BY DECREASING WIND SATURDAY EVENING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...SHOWERS WILL DEVELOP LATE TONIGHT AND CONTINUE INTO SATURDAY WITH THE SNOW LEVEL DROPPING TO NEAR 3000 FT. ANOTHER STORM SYSTEM WILL RESULT IN A SLIGHT CHANCE OF SHOWERS ON MONDAY MAINLY TO THE EAST OF TUCSON AND OVER HIGHER TERRAIN. DAYTIME TEMPERATURES SATURDAY THROUGH TUESDAY WILL BE 10-15 DEGREES COOLER THAN NORMAL. WARMER CONDITIONS WILL RETURN TO THE AREA LATE NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST SATURDAY FOR AZZ503-504-506>515 ABOVE 4000 FEET. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
955 AM MST SAT FEB 9 2013 .UPDATE... && .SHORT TERM...PRETTY GOOD MODEL CONSENSUS NOW ON THE STORM TRACK...SIMILAR TO WHAT THE ECMWF HAS BEEN SHOWING FOR DAYS. DIFFERENCES NOW APPEAR TO BE MAINLY DUE TO RESOLUTION AND PRECIP PROCESSES IN THE MODELS. IN GENERAL THE TREND HAS BEEN TO SHIFT THE AREA OF HEAVY SNOW INTO NORTHEASTERN COLORADO AND THE SOUTHERN NEBRASKA PANHANDLE. PATTERNS ARE SIMILAR IN ALL THE MODELS WITH A BAND FROM A LITTLE WAYS EAST OR NORTHEAST OF DENVER UP TOWARD SIDNEY OR OGALLALA NEBRASKA. THE NAM HAS THE STRONGEST DEVELOPMENT PER ITS RESOLUTION AND PRODUCES A 10-20 INCH SNOW BAND THAT STARTS NEAR DIA AND RUNS NORTHEAST ACROSS LOGAN COUNTY. NOT READY TO BITE ON THAT INTENSITY THOUGH THE INSTABILITY IS THERE AND I WOULD NOT RULE IT OUT...I WILL ALLOW FOR THE POSSIBILITY OF AT LEAST HALF THAT WHICH COULD BRING BLIZZARD CONDITIONS FURTHER SOUTH AND WEST. DOWNSLOPE OFF THE CHEYENNE RIDGE WILL SERIOUSLY LIMIT THE SNOWFALL ACROSS WELD AND LARIMER COUNTIES AND SOUTHWARD INTO THE DENVER AREA...THOUGH IT WILL BE INTERESTING TO SEE HOW MUCH THE AREA EAST OF DENVER GETS WHERE THE WIND IS RUNNING UPHILL AGAIN. I DID RAISE ACCUMULATIONS IN THESE MARGINAL AREAS FROM NORTHEAST WELD COUNTY DOWN TO LIMON...AND WITH SLIGHTLY STRONGER WINDS TOO THIS WILL REQUIRE EXPANDING THE BLIZZARD WARNING INTO NE WELD AND MORGAN COUNTIES. FURTHER WEST NOT MUCH TO CHANGE...AREAS NEAR THE FOOTHILLS COULD GET SKUNKED THOUGH THE CONVECTIVE BAND MOVING ACROSS THE MOUNTAINS NOW LOOKS TO HAVE DECENT INTENSITY...SO THE IDEA OF AN INCH OR TWO IN A FEW HOURS CLOSE TO THE FRONT RANGE STILL LOOKS LIKE THE MOST LIKELY SCENARIO. THIS COULD COME FAST ENOUGH TO CAUSE SOME PROBLEMS AROUND DENVER...BUT THEN IT SHOULD END BY MIDNIGHT AND THE MAIN SHOW WILL CONTINUE TO THE EAST. && .AVIATION...NO BIG CHANGES AT THIS POINT. IT IS LOOKING LIKE THERE MAY BE A PERIOD OF PREVAILING IFR CONDITIONS DURING THE EARLY EVENING...WILL HAVE TO LOOK AT THAT FURTHER. MORE UNCERTAINTY ABOUT KDEN SNOW AMOUNTS AS WELL...LOOKING MORE LIKE 2-4 INCHES THAN 1-2 INCHES WHICH COULD CAUSE A BIT MORE BLOWING/DRIFTING. LESS SNOW AT KBJC AND PROBABLY KAPA AS WELL. && .PREV DISCUSSION... /ISSUED 432 AM MST SAT FEB 9 2013/ SHORT TERM...THE POTENT UPPER LEVEL LOW IS STILL EXPECTED TO MOVE OVER COLORADO TODAY AND TONIGHT...EVENTUALLY BRINGING PRECIPITATION ACROSS THE ENTIRE FORECAST AREA. INITIALLY...EASTERN COLORADO IS UNDER A SIZABLE DRY SLOT OUT AHEAD OF THE UPPER LEVEL SYSTEM. THIS HAS KEPT SKIES ACROSS THE PLAINS CLEAR OVERNIGHT WHILE MOUNTAIN AREAS HAVE SEEN INCREASING CLOUDS AND A FEW SNOW SHOWERS. SATELLITE IMAGERY IS BEGINNING TO SHOW DECENT CLOUD TOP COOLING OVER EASTERN UTAH AND FAR WESTERN COLORADO AS THE STRONG DYNAMICS NEAR THE LOW CENTER LIFT THE AIRMASS. THE LATEST MODEL RUNS OF THE RAP ARE NOW SHOWING THE CENTER OF THE UPPER LOW PASSING OVER COLORADO SPRINGS ON THE WAY TO NORTHWESTERN KANSAS. THE ATTENDENT SURFACE LOW WILL ALSO REMAIN OVER THE PALMER DIVIDE...HELPING THE FRONT RANGE CORRIDOR TO COME UNDER INCREASING NORTH TO NORTHEAST WINDS LATE IN THE AFTERNOON AND EARLY EVENING. OVERALL...THE SYSTEM DOES NOT SEEM TO CONTAIN ABUNDANT MOISTURE...SO PRECIPITATION AMOUNTS SHOULD REMAIN ON THE LIGHT SIDE. HOWEVER...MODEL SOUNDINGS AND CROSS SECTIONS SHOW THAT AS THE UPPER LOW IS MOVING OVERHEAD THROUGH THE EVENING HOURS...THE MID LEVELS WILL BE FAIRLY UNSTABLE WHICH WILL ALLOW FOR STRONG RISING MOTIONS IN RESPONSE TO THE DYNAMIC LIFT FROM THE UPPER LOW. SKIES ACROSS THE PLAINS SHOULD GRADUALLY CLOUD OVER DURING THE AFTERNOON WITH RAIN SHOWERS DEVELOPING LATE. RAIN WILL THEN QUICKLY CHANGE OVER TO SNOW EARLY IN THE EVENING. GIVEN THE CONVECTIVE NATURE OF THE SHOWERS...LIGHT TO MODERATE SNOW WILL BE POSSIBLE ALONG THE FRONT RANGE URBAN CORRIDOR FOR A FEW HOURS IN THE EVENING. SNOW ACCUMULATIONS UP TO 4 OR 5 INCHES CAN NOT BE RULED OUT...BUT THE MORE LIKELY TOTALS WILL BE 1 TO 3 INCHES. LATER IN THE EVENING...WINDS WILL SWITCH TO NORTHWESTERLY WHICH WILL BRING DRYING ALONG THE URBAN CORRIDOR. MOUNTAIN AREAS SHOULD RECEIVE LIGHT TO MODERATE SNOWFALL THROUGH TODAY AS THE LOW MOVES OVERHEAD AND SNOW SHOWERS OVERNIGHT AS COLD ADVECTION CONTINUES IN THE WAKE OF THE UPPER LOW. THE OTHER FORECAST CONCERN IS INCREASING NORTHERLY WINDS ACROSS THE PLAINS TONIGHT AS THE SURFACE LOW DEEPENS ALONG THE EASTERN BORDER. THE COMBINATION OF WIND AND SNOW OVER THE NORTHEAST CORNER WILL NECESSITATE UPGRADING THE BLIZZARD WATCH TO A BLIZZARD WARNING. LONG TERM...THE UPPER LEVEL STORM SYSTEM WILL MOVE QUICKLY NORTHEAST OF THE AREA ON SUN HOWEVER SOME SNOW WILL LINGER OVER THE FAR NERN PLAINS THRU MID MORNING BEFORE GRADUALLY ENDING BY MIDDAY. WINDS WILL REMAIN VERY GUSTY THRU SUN AFTN SO EXPECT A LOT OF BLOWING SNOW AND POOR VISBILITIES FM AKRON TO STERLING EASTWARD SO WILL KEEP BLIZZARD WARNING THRU THE AFTN HOURS. ELSEWHERE SOME OROGRAPHIC SNOW WILL CONTINUE IN THE MTNS DUE TO ABUNDANT MOISTURE AND DECENT LAPSE RATES. ALONG THE FRONT RANGE DOWNSLOPE NWLY LOW LVL FLOW WILL LIMIT PCPN CHANCES HOWEVER WINDS WILL BE GUSTY FM THE WY BORDER SOUTHWARD ALONG I-25 TOWARD DENVER. AS FOR HIGHS READINGS SHOULD STAY IN THE 30S ACROSS NERN CO. FOR SUN NIGHT INTO MON A SECONDARY UPPER LEVEL SYSTEM WILL MOVE SOUTHWARD OVER THE AREA. IN ADDITION A SECOND SURGE OF COLDER AIR MAY ACCOMPANY THIS TROUGH WITH WK UPSLOPE FLOW SUN NIGHT INTO MON IN AND NR THE FOOTHILLS AND OVER THE PALMER DIVIDE. THUS COULD SEE A CHC OF LIGHT SNOW OVERNIGHT INTO MONDAY MOST OF THE ACTIVITY WEST OF I-25. OVER THE NERN PLAINS IT WILL BE DRY WITH SOME GUSTY WINDS OVER THE FAR NERN CORNER BUT NOT NEARLY AS STG AS SUN. IN THE MTNS ABUNDANT MOISTURE WILL CONTINUE SUN NIGHT AND MON WITH DECENT LAPSE RATES HOWEVER THE FLOW AT 700 MB IS WEAK SWLY. WILL LIKELY SEE MORE LIGHT SNOW WITH SOME MINOR ACCUMULATIONS. HIGHS ON MON WILL BE COLD WITH READINGS IN THE MID 20S TO AROUND 30 ACROSS NERN CO. BY TUE THE UPPER LEVEL TROUGH WILL MOVE SOUTH OF THE AREA WITH DRYING AIR MOVING IN. THUS SHOULD END PCPN CHANCES. 850-700 MB TEMPS BEGIN TO RISE SO SHOULD SEE HIGHS IN THE UPPER 30S TO LOWER 40S ALTHOUGH SNOW COVER OVER THE FAR NERN CORNER MAY KEEP READINGS IN THE LOWER TO MID 30S. FOR WED THE FLOW ALOFT WILL BECOME NWLY WITH SOME MOISTURE MOVING BACK INTO THE MTNS BY AFTN SO WILL MENTION A SLIGHT CHC OF SNOW. OVER NERN CO IT WILL BE DRY WITH TEMPS MODERATING BACK INTO THE 40S. FOR WED NIGHT AND THU THERE ARE DIFFERENCES BETWEEN THE ECMWF AND THE GFS WITH REGARDS TO A DISTURBANCE EMBEDDED IN THE NWLY FLOW. THE ECMWF HAS THIS FEATURE MOVING ACROSS NRN CO WED NIGHT INTO EARLY THU MORNING WITH A GOOD CHC OF SNOW IN THE MTNS. OVER THE PLAINS IT HAS A BORA TYPE FNT MOVING ACROSS WITH NO PCPN. MEANWHILE THE GFS IS HAS THE FEATURE MOVING ACROSS THU AFTN INTO THU EVENING AS ANOTHER SURGE OF COLDER AIR MOVES INTO NERN CO. AS A RESULT THIS PRODUCES A CHC OF SNOW OVER NERN CO THU AFTN INTO THU EVENING. THIS FAR OUT NOT SURE WHAT TO BELIEVE SO WILL JUST LEAVE IN LOW POPS FOR NERN CO ON THU. IN THE MTNS WILL MENTION A CHC OF SNOW WED NIGHT INTO THU. BY FRI NNW FLOW ALOFT IS SHOWN OVER THE AREA. THE ECMWF SHOWS ANOTHER POSSIBLE WAVE EMBEDDED IN THE FLOW MOVING ACROSS DURING THE DAY WHILE THE GFS SHOWS NOTHING. MEANWHILE THE ECMWF SHOWS ANOTHER CDFNT AFFECTING NERN CO WHILE THE GFS DOES NOT SHOW THIS FNT. AS A RESULT THE ECMWF GENERATES SOME UPSLOPE FLOW AND A CHC OF LIGHT SNOW ALONG THE FNT RANGE ON FRI. FOR NOW WILL JUST MENTION LOW POPS IN THE MTNS AND ALONG THE FRONT RANGE. AVIATION...CEILINGS WILL GRADUALLY LOWER THROUGH THE AFTERNOON HOURS WITH A FAIR AMOUNT OF VIRGA PRECEDING SHOWERS THAT DEVELOP AFTER 22Z. PRECIPITATION SHOULD BEGIN AS RAIN BUT THEN QUICKLY CHANGE TO SNOW AFTER ABOUT 00Z. CEILINGS COULD DROP BELOW 6000 FEET AGL BY 22Z AND MAY THEN DROP TO MVFR BY 01Z. SNOW SHOWERS THROUGH THE EVENING WILL DROP CEILINGS AND VSBYS INTO THE IFR CATEGORY. IMPROVING CONDITIONS ARE EXPECTED AFTER 06Z. SNOW ACCUMULATIONS OF 1 TO 3 INCHES CAN BE EXPECTED...BUT IF MULTIPLE SNOW SHOWERS MOVE OVER THE AIRPORT...AMOUNTS UP TO 5 INCHES WILL BE POSSIBLE. && .BOU WATCHES/WARNINGS/ADVISORIES... BLIZZARD WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST SUNDAY FOR COZ048>051. BLIZZARD WARNING FROM 5 PM THIS AFTERNOON TO 11 AM MST SUNDAY FOR COZ042-044. WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 11 AM MST SUNDAY FOR COZ033-034. WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR COZ031. && $$ SHORT TERM...DANKERS LONG TERM....RPK AVIATION/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
432 AM MST SAT FEB 9 2013 .SHORT TERM...THE POTENT UPPER LEVEL LOW IS STILL EXPECTED TO MOVE OVER COLORADO TODAY AND TONIGHT...EVENTUALLY BRINGING PRECIPITATION ACROSS THE ENTIRE FORECAST AREA. INITIALLY...EASTERN COLORADO IS UNDER A SIZABLE DRY SLOT OUT AHEAD OF THE UPPER LEVEL SYSTEM. THIS HAS KEPT SKIES ACROSS THE PLAINS CLEAR OVERNIGHT WHILE MOUNTAIN AREAS HAVE SEEN INCREASING CLOUDS AND A FEW SNOW SHOWERS. SATELLITE IMAGERY IS BEGINNING TO SHOW DECENT CLOUD TOP COOLING OVER EASTERN UTAH AND FAR WESTERN COLORADO AS THE STRONG DYNAMICS NEAR THE LOW CENTER LIFT THE AIRMASS. THE LATEST MODEL RUNS OF THE RAP ARE NOW SHOWING THE CENTER OF THE UPPER LOW PASSING OVER COLORADO SPRINGS ON THE WAY TO NORTHWESTERN KANSAS. THE ATTENDENT SURFACE LOW WILL ALSO REMAIN OVER THE PALMER DIVIDE...HELPING THE FRONT RANGE CORRIDOR TO COME UNDER INCREASING NORTH TO NORTHEAST WINDS LATE IN THE AFTERNOON AND EARLY EVENING. OVERALL...THE SYSTEM DOES NOT SEEM TO CONTAIN ABUNDANT MOISTURE...SO PRECIPITATION AMOUNTS SHOULD REMAIN ON THE LIGHT SIDE. HOWEVER...MODEL SOUNDINGS AND CROSS SECTIONS SHOW THAT AS THE UPPER LOW IS MOVING OVERHEAD THROUGH THE EVENING HOURS...THE MID LEVELS WILL BE FAIRLY UNSTABLE WHICH WILL ALLOW FOR STRONG RISING MOTIONS IN RESPONSE TO THE DYNAMIC LIFT FROM THE UPPER LOW. SKIES ACROSS THE PLAINS SHOULD GRADUALLY CLOUD OVER DURING THE AFTERNOON WITH RAIN SHOWERS DEVELOPING LATE. RAIN WILL THEN QUICKLY CHANGE OVER TO SNOW EARLY IN THE EVENING. GIVEN THE CONVECTIVE NATURE OF THE SHOWERS...LIGHT TO MODERATE SNOW WILL BE POSSIBLE ALONG THE FRONT RANGE URBAN CORRIDOR FOR A FEW HOURS IN THE EVENING. SNOW ACCUMULATIONS UP TO 4 OR 5 INCHES CAN NOT BE RULED OUT...BUT THE MORE LIKELY TOTALS WILL BE 1 TO 3 INCHES. LATER IN THE EVENING...WINDS WILL SWITCH TO NORTHWESTERLY WHICH WILL BRING DRYING ALONG THE URBAN CORRIDOR. MOUNTAIN AREAS SHOULD RECEIVE LIGHT TO MODERATE SNOWFALL THROUGH TODAY AS THE LOW MOVES OVERHEAD AND SNOW SHOWERS OVERNIGHT AS COLD ADVECTION CONTINUES IN THE WAKE OF THE UPPER LOW. THE OTHER FORECAST CONCERN IS INCREASING NORTHERLY WINDS ACROSS THE PLAINS TONIGHT AS THE SURFACE LOW DEEPENS ALONG THE EASTERN BORDER. THE COMBINATION OF WIND AND SNOW OVER THE NORTHEAST CORNER WILL NECESSITATE UPGRADING THE BLIZZARD WATCH TO A BLIZZARD WARNING. .LONG TERM...THE UPPER LEVEL STORM SYSTEM WILL MOVE QUICKLY NORTHEAST OF THE AREA ON SUN HOWEVER SOME SNOW WILL LINGER OVER THE FAR NERN PLAINS THRU MID MORNING BEFORE GRADUALLY ENDING BY MIDDAY. WINDS WILL REMAIN VERY GUSTY THRU SUN AFTN SO EXPECT A LOT OF BLOWING SNOW AND POOR VISBILITIES FM AKRON TO STERLING EASTWARD SO WILL KEEP BLIZZARD WARNING THRU THE AFTN HOURS. ELSEWHERE SOME OROGRAPHIC SNOW WILL CONTINUE IN THE MTNS DUE TO ABUNDANT MOISTURE AND DECENT LAPSE RATES. ALONG THE FRONT RANGE DOWNSLOPE NWLY LOW LVL FLOW WILL LIMIT PCPN CHANCES HOWEVER WINDS WILL BE GUSTY FM THE WY BORDER SOUTHWARD ALONG I-25 TOWARD DENVER. AS FOR HIGHS READINGS SHOULD STAY IN THE 30S ACROSS NERN CO. FOR SUN NIGHT INTO MON A SECONDARY UPPER LEVEL SYSTEM WILL MOVE SOUTHWARD OVER THE AREA. IN ADDITION A SECOND SURGE OF COLDER AIR MAY ACCOMPANY THIS TROUGH WITH WK UPSLOPE FLOW SUN NIGHT INTO MON IN AND NR THE FOOTHILLS AND OVER THE PALMER DIVIDE. THUS COULD SEE A CHC OF LIGHT SNOW OVERNIGHT INTO MONDAY MOST OF THE ACTIVITY WEST OF I-25. OVER THE NERN PLAINS IT WILL BE DRY WITH SOME GUSTY WINDS OVER THE FAR NERN CORNER BUT NOT NEARLY AS STG AS SUN. IN THE MTNS ABUNDANT MOISTURE WILL CONTINUE SUN NIGHT AND MON WITH DECENT LAPSE RATES HOWEVER THE FLOW AT 700 MB IS WEAK SWLY. WILL LIKELY SEE MORE LIGHT SNOW WITH SOME MINOR ACCUMULATIONS. HIGHS ON MON WILL BE COLD WITH READINGS IN THE MID 20S TO AROUND 30 ACROSS NERN CO. BY TUE THE UPPER LEVEL TROUGH WILL MOVE SOUTH OF THE AREA WITH DRYING AIR MOVING IN. THUS SHOULD END PCPN CHANCES. 850-700 MB TEMPS BEGIN TO RISE SO SHOULD SEE HIGHS IN THE UPPER 30S TO LOWER 40S ALTHOUGH SNOW COVER OVER THE FAR NERN CORNER MAY KEEP READINGS IN THE LOWER TO MID 30S. FOR WED THE FLOW ALOFT WILL BECOME NWLY WITH SOME MOISTURE MOVING BACK INTO THE MTNS BY AFTN SO WILL MENTION A SLIGHT CHC OF SNOW. OVER NERN CO IT WILL BE DRY WITH TEMPS MODERATING BACK INTO THE 40S. FOR WED NIGHT AND THU THERE ARE DIFFERENCES BETWEEN THE ECMWF AND THE GFS WITH REGARDS TO A DISTURBANCE EMBEDDED IN THE NWLY FLOW. THE ECMWF HAS THIS FEATURE MOVING ACROSS NRN CO WED NIGHT INTO EARLY THU MORNING WITH A GOOD CHC OF SNOW IN THE MTNS. OVER THE PLAINS IT HAS A BORA TYPE FNT MOVING ACROSS WITH NO PCPN. MEANWHILE THE GFS IS HAS THE FEATURE MOVING ACROSS THU AFTN INTO THU EVENING AS ANOTHER SURGE OF COLDER AIR MOVES INTO NERN CO. AS A RESULT THIS PRODUCES A CHC OF SNOW OVER NERN CO THU AFTN INTO THU EVENING. THIS FAR OUT NOT SURE WHAT TO BELIEVE SO WILL JUST LEAVE IN LOW POPS FOR NERN CO ON THU. IN THE MTNS WILL MENTION A CHC OF SNOW WED NIGHT INTO THU. BY FRI NNW FLOW ALOFT IS SHOWN OVER THE AREA. THE ECMWF SHOWS ANOTHER POSSIBLE WAVE EMBEDDED IN THE FLOW MOVING ACROSS DURING THE DAY WHILE THE GFS SHOWS NOTHING. MEANWHILE THE ECMWF SHOWS ANOTHER CDFNT AFFECTING NERN CO WHILE THE GFS DOES NOT SHOW THIS FNT. AS A RESULT THE ECMWF GENERATES SOME UPSLOPE FLOW AND A CHC OF LIGHT SNOW ALONG THE FNT RANGE ON FRI. FOR NOW WILL JUST MENTION LOW POPS IN THE MTNS AND ALONG THE FRONT RANGE. && .AVIATION...CEILINGS WILL GRADUALLY LOWER THROUGH THE AFTERNOON HOURS WITH A FAIR AMOUNT OF VIRGA PRECEDING SHOWERS THAT DEVELOP AFTER 22Z. PRECIPITATION SHOULD BEGIN AS RAIN BUT THEN QUICKLY CHANGE TO SNOW AFTER ABOUT 00Z. CEILINGS COULD DROP BELOW 6000 FEET AGL BY 22Z AND MAY THEN DROP TO MVFR BY 01Z. SNOW SHOWERS THROUGH THE EVENING WILL DROP CEILINGS AND VSBYS INTO THE IFR CATEGORY. IMPROVING CONDITIONS ARE EXPECTED AFTER 06Z. SNOW ACCUMULATIONS OF 1 TO 3 INCHES CAN BE EXPECTED...BUT IF MULTIPLE SNOW SHOWERS MOVE OVER THE AIRPORT...AMOUNTS UP TO 5 INCHES WILL BE POSSIBLE. && .BOU WATCHES/WARNINGS/ADVISORIES... BLIZZARD WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST SUNDAY FOR COZ048>051. WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 11 AM MST SUNDAY FOR COZ033-034. WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 11 AM MST SUNDAY FOR COZ031. && $$ SHORT TERM...DANKERS LONG TERM....RPK AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1010 PM MST FRI FEB 8 2013 .UPDATE... && .SHORT TERM...FEW CHANGES NECESSARY TO EVENING FORECAST. SNOW SHOWERS SLOW TO DEVELOP IN THE NORTH CENTRAL MOUNTAINS AS THE UPPER LOW AND BEST FORCING STILL WELL UPSTREAM OVER NEVADA AND WESTERN UTAH. THROUGH THE NIGHT SHOULD SEE A STEADY INFLUX OF MID AND HIGH CLOUDS OVER THE NORTHEAST PLAINS AND LOWER CLOUDS MTN AND WESTERN VALLEYS WITH SOUTHWESTERLY FLOW. MEANWHILE GUSTY SOUTHERLY SFC WINDS ON THE PLAINS...ROUGHLY EAST OF A STERLING TO LIMON LINE MAY CONTINUE TO BLOW FOR MUCH OF THE NIGHT AT SPEEDS OF 15-30KTS. LASTLY...00Z/NAM SUGGESTS SOME POOLING OF BOUNDARY LAYER MOISTURE JUST NORTH OF THE DENVER AREA TOWARD DAWN WITH LIGHT NORTH-NORTHWEST SFC FLOW. HENCE COULD SEE PATCHY SHALLOW FOG IN THIS AREA...POSSIBLY AS FAR SOUTH AS DIA...BUT PROBABLY FOR ONLY A FEW HRS ROUND SUNRISE. .AVIATION...VFR CONDITIONS ANTICIPATED AT DENVER AREA AIRPORTS THROUGH 11Z TONIGHT. FROM 11Z TO AROUND 14Z THERE IS A SLIGHT CHANCE DIA COULD SEE SOME SHALLOW FOG NORTH OF THE AIRPORT MOVING OVER PARTS OF THE AIRPORT. FOG PROBABLY SHALLOW AND THIN SO OBSCURATION TO VISIBILITY SHOULD BE MINOR. SOUTHERLY WINDS OF 4 TO 12KTS IN THE DENVER AREA EXPECTED TO GRADUALLY SHIFT TO A LIGHT NORTH-NORTHWEST DIRECTION TOWARDS MORNING WITH A SFC LOW FORMING ON THE PLAINS EAST OF DENVER. && .PREV DISCUSSION... /ISSUED 405 PM MST FRI FEB 8 2013/ SHORT TERM...UPPER LEVEL TROUGH AND MID LEVEL LOW OVER SOUTHERN GREAT BASIN WITH STRONG SOUTHWEST FLOW ACROSS COLORADO. WINDS HAVE BEEN GUSTY ACROSS MUCH OF THE PLAINS WHICH HELPED TO ELEVATE THE FIRE DANGER. HUMIDITY READINGS WERE IN THE MID AND UPPER TEENS WHICH KEPT CRITICAL FIRE WEATHER CONCERNS TO A MINIMUM. A WEAK BOUNDARY EXTENDING FROM EAST OF DENVER TO THE SOUTHERN DENVER SUBURBS HAS KEPT THE GUSTY WINDS FROM SPREADING NORTH ACROSS THE DENVER AREA. OVER THE MOUNTAINS... DRY CONDITIONS PREVAILING WITH SOME MID AND HIGH LEVEL CLOUDS. WINDS WERE A BIT GUSTY ACROSS THE RIDGES AND SOUTHERN FOOTHILLS. MODELS SHOW THE SYSTEM MOVING EAST DURING THE EVENING...WITH MID LEVEL LOW OVER SOUTHEAST NEVADA. SOUTHWEST FLOW ALOFT OVER COLORADO BECOMES A BIT MORE SOUTHERLY. LATEST RAP SHOWS MID LEVEL ASCENT INCREASING ACROSS MOUNTAINS WITH LAPSE RATE AROUND 7 C/KM. MOISTURE DOES INCREASE DURING THE EVENING...WITH THE BETTER MOISTURE HOLDING OFF UNTIL AFTER MIDNIGHT. SHOULD SEE SOME SHOWERS DEVELOPING INITIALLY OVER THE HIGHER RIDGES...WITH A BETTER CHANCE AFTER MIDNIGHT WHEN THE MOISTURE INCREASES. FLOW NOT ALL THAN FAVORABLE FOR SNOWFALL OVERNIGHT...THOUGH A FEW SPOTS ALONG THE EXTREME WESTERLY SECTIONS OF THE FORECAST AREAS. ACROSS PLAINS...WINDS TO GRADUALLY AND BECOME MORE SOUTHWEST WITH VARIABLE MID AND HIGH LEVEL CLOUDS. ON SATURDAY...MODELS SHOW UPPER TROUGH MOVING INTO THE GREAT BASIN AND WESTERN COLORADO DURING THE MORNING...THEN ACROSS COLORADO DURING THE AFTERNOON. THE MID LEVEL LOW SHIFTS FROM SOUTHWEST UTAH AND SOUTHWEST NEVADA INTO WESTERN COLORADO BY 18Z...THEN OVER NORTHEAST COLORADO BY 00Z SATURDAY EVENING. MOISTURE INCREASES AND DEEPENS ACROSS THE MOUNTAINS DURING THE DAY ALONG WITH INCREASING MID LEVEL QG ACCENT. WITH LAPSE RATES AROUND 7 C/KM EXPECTED... AIRMASS BECOMES SLIGHTLY UNSTABLE. SO DESPITE THE UNFAVORABLE OROGRAPHICS...SHOULD SEE SNOW INCREASE ACROSS THE MOUNTAINS BY THE AFTERNOON. WILL HOIST AN ADVISORY FOR SNOW FOR ZONE 31 BEGINNING AT 18Z...AND ADVISORIES FOR ZONES 33 AND 34 BEGINNING 21Z. THE ADVISORIES WILL EXTEND THROUGH SUNDAY MORNING. SNOW AMOUNTS WILL INITIALLY BE LIGHT BUT SHOULD INCREASE DURING THE AFTERNOON. ALONG FOOTHILLS...THE TRACK OF THE LOW WILL PROVIDE FOR MORE OF A DOWNSLOPE NORTHWEST COMPONENT. BUT THERE WILL BE ENOUGH ASCENT TO HELP OFFSET THE DOWSLOPE FLOW. WILL CONTINUE THE LIKELY POPS WITH LIGHT SNOW AMOUNTS...THOUGH MAY BE A BIT MORE WIDESPREAD NEAR THE WYOMING BORDER. ACROSS THE PLAINS...MODELS SHOW NORTHWESTERLIES SPREADING ACROSS THE AREA LATE MORNING AND AFTERNOON. THIS DOWNSLOPE WILL INITIALLY KEEP THE PRECIP LIMITED...BUT CHANCES TO INCREASE BY THE EVENING WHEN THE LIFT GETS GREATER. CURRENT FORECASTS STILL SEEM ON TRACK AND WILL NOT DEVIATE MUCH. DID CHANGE THE RAIN/SNOW CHANCES TO ALL SNOW ACROSS NORTHERN WELD AND NORTHERN LARIMER COUNTIES AS THE COLDER AIR APPEARS TO GET THERE SOONER. LONG TERM...MODELS HAVE BEEN PRETTY CONSISTENT WITH THE DEVELOPMENT OF THE LOW MOVING ACROSS COLORADO INTO NEBRASKA SATURDAY NIGHT AND SUNDAY. THE ECMWF REMAINS FURTHER SOUTH THAN A CLUSTER OF OTHER MODELS BY ABOUT 100 MILES...BRINGING THE LOW ACROSS EAST CENTRAL COLORADO WHILE THE REST GO ACROSS THE NORTHEAST CORNER. AS A RESULT THE LAST TWO RUNS OF THE ECMWF HAVE PRODUCE ONE HALF TO ONE INCH OF LIQUID PRECIPITATION OVER THE CORNER...WHILE OTHER MODELS HAVE LESS WITH THE HEAVY SNOW IN NEBRASKA. OUR FORECAST HAS BEEN A COMPROMISE AND I SEE LITTLE REASON TO CHANGE THIS. SO THIS PACKAGE IS PRIMARILY AN UPDATE TO ISSUE ADVISORIES FOR THE HIGH MOUNTAINS. FIRST FOR THE PLAINS...OUR COMPROMISE SOLUTION WOULD PROBABLY STILL PRODUCE BLIZZARD CONDITIONS IN THE WATCH AREA...WITH SOME CONCERN ABOUT NORTHERN PORTIONS OF WELD AND WASHINGTON COUNTIES AS WELL. NOT NECESSARILY HEAVY SNOW AMOUNTS BUT THE COMBINATION OF SNOW WITH THE STRONG WINDS. FURTHER WEST THERE SHOULD BE SOME SNOW AND WIND THAT MAY STILL BE ENOUGH TO CAUSE TRAVEL DIFFICULTIES. STILL UNRESOLVED IS THE LENGTH OF TIME THAT IT WILL SNOW BEFORE THE DOWNSLOPE WINDS CUT IT OFF SATURDAY EVENING. THE MODELS PRODUCE VERY LITTLE SNOW ALONG THE FRONT RANGE...AND WE HAVE BEEN PRESUMING THAT THERE WOULD BE AT LEAST A BRIEF PERIOD OF SNOW WITH THE TROUGH AXIS. THE STRONGER SOLUTIONS COULD LEAD TO A 3-6 HOUR PERIOD OF NORTH WINDS AT LOW LEVELS...WHICH WOULD ALLOW FOR HEAVIER SNOW THAN WE ARE FORECASTING. AT THIS POINT OUR FORECAST STILL SEEMS A PRUDENT MIDDLE GROUND BETWEEN THE POSSIBLE SOLUTIONS. FOR THE MOUNTAINS WE WILL NEED TO WATCH THE AMOUNTS AS IT IS FAIRLY UNSTABLE SATURDAY NIGHT...IF THE WIND DIRECTION IS MORE WESTERLY THIS WOULD BE BAD FOR THE FRONT RANGE CITIES...BUT WOULD PRODUCE MORE SNOW IN THE MOUNTAINS AND WE COULD NEED A WARNING. AS THE MAIN SYSTEM EXITS...WEAK ISENTROPIC LIFT CREEPS NORTHWARD AS A DEFORMATION ZONE ON THE NORTH SIDE OF THE SOUTHWEST LOW MOVES IN. THIS COULD PRODUCE LIGHT SNOW OVER THE SOUTHERN AND WESTERN PARTS OF OUR AREA...MORE LIKELY IN THE MOUNTAINS BUT NOT MUCH REALLY TO STOP IT REACHING THE GROUND ON THE PALMER DIVIDE EITHER. I NUDGED POPS/CLOUDS UP A BIT MORE SUNDAY NIGHT INTO MONDAY FOR THIS...THOUGH IT APPEARS LITTLE THREAT OF SIGNIFICANT SNOWFALL AN INCH TO MESS UP THE MONDAY MORNING RUSH HOUR IS NOT OUT OF THE QUESTION. NOT MUCH CHANGE TO THE REST...WARMING TREND THROUGH WEDNESDAY. THERE COULD BE SOME LINGERING MOISTURE FOR VERY LIGHT SNOW IN THE MOUNTAINS BUT ODDS OF THIS GET SMALLER WITH TIME. STILL LOOKING FOR A TROUGH IN NW FLOW WEDNESDAY NIGHT OR EARLY THURSDAY. SOME SOLUTIONS ARE STRONGER WITH THIS WITH MORE COLD ADVECTION ALOFT PRODUCING BETTER DEVELOPMENT AS IT MOVES OVER THE ROCKIES. THE LOW THREAT OF SNOW WE HAVE IS APPROPRIATE...MAY NEED MORE FOR THE MOUNTAINS. IT WILL BE COLDER THURSDAY AND FRIDAY...SOME OF THE SOLUTIONS ARE MUCH COLDER...MODEL CONSENSUS IS JUST DROPPING BACK INTO THE 30S AGAIN AND WE WILL STICK WITH THAT FOR NOW. AVIATION...BOUNDARY JUST SOUTH AND EAST OF THE DENVER AREA HAS KEPT THE GUSTY SOUTHERLY WINDS FROM REACHING DEN. SKEPTICAL ABOUT BOUNDARY MOVING NORTHWARD THROUGH THE EVENING SO WILL KEEP THE GUSTS OUT OF DEN. WINDS TO DECREASE AT APA DURING THE EVENING WITH SOUTHERLY DRAINAGE PATTERN DOMINATING ACROSS THE AREA AIRPORTS BY 03Z. VFR TO CONTINUE WITH UNLIMITED CEILINGS. ON SATURDAY...MID AND HIGH LEVEL MOISTURE TO INCREASE WITH CEILINGS AROUND 10000 FEET AGL BY 18Z WIND TO SHIFT TO THE NORTHWEST AFTER 15Z WITH SPEEDS AROUND 12 KTS. CEILINGS TO GRADUALLY LOWER DURING THE AFTERNOON WITH 6000 FEET AGL PREVAILING AROUND 21Z. THERE WILL BE A CHANCE OF SHOWERS DEVELOPING DURING THE AFTERNOON...BEST CHANCE AFTER 21Z. WILL CONTINUE A PROB30 OF A RAIN/SNOW MIX FOR DEN AND INCLUDE FOR BJC AND APA WITH LOWER CEILINGS. ANY SNOW ACCUMULATIONS WILL BE LIGHT...LESS THAN ONE HALF INCH THROUGH THE AFTERNOON AND CONFINED TO THE GRASSY AREAS. && .BOU WATCHES/WARNINGS/ADVISORIES... BLIZZARD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR COZ048-050-051. WINTER WEATHER ADVISORY FROM 2 PM SATURDAY TO 11 AM MST SUNDAY FOR COZ033-034. WINTER WEATHER ADVISORY FROM 11 AM SATURDAY TO 11 AM MST SUNDAY FOR COZ031. && $$ SHORT TERM...BAKER/D_L LONG TERM....GIMMESTAD AVIATION...BAKER/D_L
AREA FORECAST DISCUSSION
NWS ALBANY NY
934 PM EST SUN FEB 10 2013 .SYNOPSIS... HIGH PRESSURE ALONG THE EASTERN SEABOARD WILL SLIDE OFFSHORE TONIGHT. A STORM WILL CROSS THE UPPER GREAT LAKES TOMORROW...AND MOVE TO THE MARITIMES BY TUESDAY. IT WILL DRAG A WARM FRONT ACROSS THE REGION MONDAY...WITH A WINTRY MIX FOR A FEW HOURS BEFORE CHANGING TO RAIN. TWO COLD FRONTS WILL FOLLOW LATE MONDAY. TUESDAY WEAK HIGH PRESSURE WILL CREST OVER THE REGION. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... ...WINTER WEATHER ADVISORY ISSUED FOR MIXED PRECIPITATION LATE TONIGHT AND TOMORROW MORNING...BUT INTO THE AFTERNOON OVER NORTHERN AREAS... AS OF 930 PM EST...CLEAR SKIES...CALM WINDS...AND A RELATIVELY FRESH/DEEP SNOWPACK HAVE ALLOWED TEMPS TO ONCE AGAIN PLUMMET AFTER SUNSET...WITH TEMPS ALREADY FALLING INTO THE SINGLE DIGITS TO LOWER/MID TEENS ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS AND LAKE GEORGE/SARATOGA REGIONS...AND GENERALLY 10-15 ABOVE ELSEWHERE. UNTIL CLOUDS ARRIVE AND THICKEN BETWEEN 10 PM AND MIDNIGHT...TEMPS SHOULD CONTINUE TO DROP...SO HAVE LOWERED FORECAST MINS BY AT LEAST 5-8 DEGREES IN MOST AREAS...WHICH STILL MAY NOT BE ENOUGH. EXPECT MINS TO FALL INTO ZERO TO 5 ABOVE RANGE ACROSS THE SOUTHERN ADIRONDACKS...LAKE GEORGE SARATOGA REGION...AND SHELTERED VALLEYS ACROSS WESTERN NEW ENGLAND...WITH GENERALLY 5 ABOVE TO 15 ABOVE ELSEWHERE. TEMPS SHOULD THEN HOLD NEARLY STEADY AROUND MIDNIGHT...BEFORE RISING THEREAFTER AS CLOUDS THICKEN...AND SOUTH WINDS DEVELOP. AS FOR PRECIPITATION CHANCES...AN ABUNDANCE OF LOW LEVEL DRY AIR WAS NOTED ON REGIONAL 00Z SOUNDINGS...AND ACCORDING TO LATEST RADAR AND SFC OBS...PRECIPITATION IS NOT REACHING THE GROUND UNTIL EXTREME SOUTHWEST PA AND POINTS S AND W. BASED ON CURRENT EXTRAPOLATION...AS WELL AS DATA FROM HRRR SUGGESTS OUR AREA SHOULD REMAIN DRY UNTIL AROUND 4 AM...WITH LIGHT PRECIPITATION THEN EXPANDING N AND E ACROSS REGION BETWEEN 4 AM AND DAYBREAK. SO...HAVE NUDGED BACK TIMING OF PRECIP ONSET FROM PREVIOUS FORECAST UNTIL MAINLY AFTER 4 AM...WITH THE BEST CHC CLOSER TO AROUND 6-7 AM IN MOST AREAS. PTYPE SHOULD START AS A MIX OF LIGHT SNOW...SLEET AND FREEZING RAIN...ALTHOUGH PERHAPS MORE IN THE SNOW/SLEET CATEGORY FOR AREAS MAINLY N OF THE MOHAWK RIVER...INTO WESTERN MA AND SOUTHERN VT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... PRECIPITATION SHOULD TRANSITION TO FREEZING RAIN OVER MOST AREAS SHORTLY AFTER DAYBREAK. THE LENGTH OF TIME OF THE FREEZING RAIN SHOULD BE SHORTEST IN THE CAPITAL DISTRICT...MID HUDSON VALLEY... SOUTHERN BERKSHIRES AND NW CT. THERE COULD BE AN INCH OR TWO OF SNOW IN NORTHERN AREAS BEFORE THE CHANGE TO FREEZING RAIN. THERE ARE SOME CONSIDERABLE UNCERTAINTIES AS TO WHEN THE TEMPERATURES WILL RISE ABOVE FREEZING...ESPECIALLY WITH THE SNOW PACK IN THE REGION. SOME AREAS IN THE SCHOHARIE VALLEY...HELDERBERGS AND EASTERN CATSKILLS COULD TAKE UNTIL AROUND NOON...AS UP TO A QUARTER INCH OF ICE IS POSSIBLE BEFORE CHANGING TO A COLD RAIN. UP TO A TENTH OF AN INCH OF ICE IS POSSIBLE IN OTHER AREAS. SOME QUESTIONS ABOUT WHETHER A QUARTER INCH OF FREEZING RAIN IS POSSIBLE IN SOUTHERN VT AND THE NORTHERN BERKSHIRES...IT DEPENDS ON WHEN THE SNOW AND SLEET CHANGES OVER. SOME TEMPERATURES IN NORTHERN AREAS AND IN PROTECTED VALLEYS WITHIN TERRAIN MAY BARELY GET ABOVE FREEZING IN THE AFTERNOON. BUT...BOUNDARY LAYER WINDS DO TURN TO WEST AND BECOME RELATIVELY STRONG...SO ANY MIXING COULD CAUSE TEMPERATURES TO JUMP QUICKLY IN THE AFTERNOON...AND THE NEXT SET OF 00Z GUIDANCE WILL HOPEFULLY SHED SOME LIGHT ON THAT POSSIBILITY. BY TOMORROW NIGHT...THE COLD FRONT SHOULD TRACK THROUGH...AND PRECIPITATION SHOULD BECOME SHOWERY. BOUNDARY LAYER TEMPERATURES DO NOT COOL TOO MUCH...AND THE WEST WINDS INCREASE. CLOUDS WITHIN THE SOUTHERN PERIPHERY OF THE UPPER SYSTEM...ALONG WITH LAKE EFFECT MOISTURE SHOULD KEEP MOSTLY CLOUDY TO CLOUDY CONDITIONS OVER THE REGION. WITH THE MIXING DUE TO THE WINDS AND THE SKY COVER...LEANING TOWARD WARMER GUIDANCE FOR NIGHTTIME LOWS...ALONG WITH SCATTERED RAIN SHOWERS BECOMING SNOW SHOWERS WHILE DECREASING IN COVERAGE. ON TUESDAY...A REINFORCING SHOT OF COOLER AIR TRACKS THROUGH THE REGION AS THE UPPER IMPULSE EXITS. THERE COULD BE ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS ASSOCIATED WITH THE FORCING AND PROXIMITY TO THE UPPER IMPULSE AS WELL AS LAKE EFFECT MOISTURE. IT SHOULD BE QUITE BREEZY TUESDAY AFTERNOON WITH SOME MIXING...EVEN WITH MORE CLOUDS THAN SUN. HIGHS TUESDAY AROUND 40 TO MID 40S IN THE VALLEYS...AND MID TO UPPER 30S IN AREAS OF TERRAIN. WINDS CONTINUE THROUGH TUESDAY NIGHT...AND PERIODS OF CLOUDS... PERHAPS CONTINUING MOSTLY CLOUDY FOR MUCH OF THE NIGHT...DEPENDING ON HOW MUCH LAKE EFFECT MOISTURE STREAMS EAST. THE DIFFERENCE IN LAKE TEMPERATURES AND BOUNDARY LAYER TEMPERATURES IS NOT QUITE AS IDEAL AS IT COULD BE FOR LAKE EFFECT SNOW BANDS...BUT STILL... THERE SHOULD BE CONSIDERABLE CLOUDS REMAINING OVER THE REGION. SO...LEANING TOWARD WARMER GUIDANCE FOR LOW TEMPERATURES TUESDAY NIGHT. WEDNESDAY SHOULD SEE INCREASING PERIODS OF SUN WITH HIGHS IN THE MID TO UPPER 30S...AROUND 30 TO LOWER 30S IN HIGHER TERRAIN. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... WE START THIS LONG TERM PORTION WITH A PROGRESSIVE AND NEAR ZONAL UPPER FLOW ACROSS THE NORTHERN TIER OF THE CONUS. THIS SHOULD ALLOW THE SOUTHERN STREAM WAVE TO REMAIN SOUTH TO FURTHER REDUCE THE IMPACT TO OUR REGION. HOWEVER...THERE IS AN ADDITIONAL SHORT WAVE SEEN IN THE GLOBAL MODELS DIVING SOUTHWARD TOWARD THE UPPER GREAT LAKES REGION. A THERMAL TROUGH AXIS APPEARS TO BE ASSOCIATED WITH THIS FEATURE AS WE WILL RETAIN THE SLIGHT CHANCE POPS FOR LIGHT SNOW WEDNESDAY NIGHT. THURSDAY...THE AFOREMENTIONED SHORT WAVE ACROSS THE GREAT LAKES REGION BEGINS TO AMPLIFY AS ADDITIONAL ENERGY DIVES INTO THIS UPSTREAM TROUGH. IN TURN...THE DOWNSTREAM RIDGE WILL AMPLIFY WHICH SHOULD RESULT IN A TRANQUIL PRECIP-FREE DAY. THE H850 TEMPS CLIMB TOWARD -4C ALONG WITH A STRENGTHENING SOUTHWEST FLOW TO RESULT IN TEMPS CLIMBING ABOVE FREEZING FOR MANY LOCATIONS. THURSDAY NIGHT INTO FRIDAY... LATEST TRENDS IN OPERATIONAL GLOBAL MODELS AND ENSEMBLES SUGGEST THE UPSTREAM TROUGH WILL CONTINUE TO AMPLIFY AS RIDGE ACROSS THE WEST COAST BUILDS. THIS IS WHERE THE INDIVIDUAL MODELS DIVERGE SOMEWHAT WITH TRACK AND INTENSITY OF THE SURFACE FEATURES AND UPPER LEVEL FEATURES. AN ASSOCIATED FRONTAL BOUNDARY IS EXPECTED TO APPROACH OR JUST SLIDE EAST OF THE REGION DURING FRIDAY. THIS IS WHERE WE WILL PLACE POPS FOR THE ENTIRE REGION WITH THE HIGHER VALUES NORTH AND WEST OF ALBANY IN CLOSER PROXIMITY TO THE CYCLONIC FLOW. SINCE BOUNDARY LAYER TEMPS WILL BE ABOVE FREEZING...THE CHANCE FOR RAIN AND/OR SNOW SHOWERS WILL EXIST. FRIDAY INTO SATURDAY... LATEST ECMWF AND GFS ENSEMBLES ALL SIGNAL THE POTENTIAL FOR ANOTHER COASTAL STORM THAT COULD IMPACT THE REGION DURING THIS TIME FRAME. THIS POTENTIAL COAST SYSTEM IS EXPECTED TO DEVELOP IN THE VICINITY OF THE DELMARVA REGION LATE IN THE DAY FRIDAY AND BEGIN ITS TRACK NORTHEAST FRIDAY NIGHT INTO SATURDAY. A COUPLE OF THE ENSEMBLE MEMBERS SUGGEST A RATHER DEEP LOW NEAR BOSTON BY 12Z SATURDAY. THERE IS A HIGH STANDARD DEVIATION SEEN IN THE BOTH THE SURFACE AND UPPER LEVEL FEATURES WHICH PLACES THIS FORECAST IN RATHER LOW CONFIDENCE. THE ECMWF SIGNALS THAT THIS LOW TO TRACK ACROSS EASTERN NEW ENGLAND WITH A DEFORMATION AXIS ACROSS UPSTATE NEW YORK FRIDAY NIGHT INTO SATURDAY. WE WILL GO WITH A LOW POPS AT THIS TIME AND WATCH TRENDS VERY CLOSELY. TEMPERATURES THROUGH THE PERIOD WILL AVERAGE NEAR NORMAL WITH PRECIPITATION NEAR TO PERHAPS ABOVE NORMAL /DEPENDING ON THE TRACK OF THAT SYSTEM LATER IN THE WEEK/ && .AVIATION /03Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS SHOULD CONTINUE THROUGH THE OVERNIGHT HOURS...WITH HIGH AND MID LEVEL CLOUDS ARRIVING AFTER MIDNIGHT...AND THICKENING SHORTLY THEREAFTER. WITHIN A FEW HOURS OF DAYBREAK...LIGHT PRECIPITATION SHOULD OVERSPREAD THE TAF SITES. AT KPOU...THE PRECIP SHOULD START AS A FREEZING RAIN/SLEET MIX. AT KALB/KPSF...THE PRECIP SHOULD BEGIN AS A BRIEF MIX OF SNOW/SLEET...BEFORE TRANSITIONING TO A FREEZING RAIN/SLEET MIX. AT KGFL...A PERIOD OF LIGHT SNOW AND SLEET SHOULD BEGIN AROUND DAYBREAK. AFTER THE PRECIP BEGINS...IT SHOULD EVENTUALLY CHANGE TO PLAIN RAIN AT KPOU FIRST BY 13Z-14Z...THEN KALB AND KPSF BETWEEN 14Z- 16Z...AND LAST AT KGFL BY AROUND 17Z. THE STEADY LIGHT TO MODERATE RAIN SHOULD THEN TAPER OFF TO PATCHY DRIZZLE DURING THE AFTERNOON. CIGS AND VSBYS SHOULD BECOME MVFR TO IFR BY MID TO LATE MORNING...WITH MAINLY IFR CONDITIONS EXPECTED FOR THE AFTERNOON. AREAS OF GROUND FOG WILL BE POSSIBLE AS MILDER...MOIST AIR POURS OVER THE COLD GROUND AND DEEP SNOWPACK ACROSS THE REGION. THIS COULD POTENTIALLY RESULT IN LIFR/VLIFR VSBYS AT TIMES. LIGHT/VARIABLE WINDS WILL TREND INTO THE SOUTH TO SOUTHEAST BY DAYBREAK AT 5-10 KT...PERHAPS A BIT HIGHER AT KALB. EXPECT MAINLY SOUTHEAST TO SOUTH WINDS THROUGH MONDAY MORNING AT 5-10 KT...TRENDING MORE INTO THE SOUTHWEST AT MOST SITES IN THE AFTERNOON. THERE IS A CHANCE FOR LOW LEVEL WIND SHEAR MONDAY MORNING...AS SFC WINDS REMAIN FROM THE SOUTHEAST TO SOUTH AT GENERALLY LESS THAN 12 KT...WHILE WINDS AROUND 1500-2000 FT AGL INCREASE FROM THE SOUTH TO SOUTHWEST AT 30-35 KT. AT THIS TIME...HAVE KEPT MENTION OF THIS OUT OF TAFS...BUT THIS MAY NEED TO BE INCLUDED WITH SUBSEQUENT TAF ISSUANCES. OUTLOOK... MON NIGHT...VFR/MVFR. CHC -SHSN. TUE-TUE NIGHT...VFR/MVFR. SLIGHT CHC -SHRA/-SHSN. WED-FRI...VFR. NO SIG WX. && .HYDROLOGY... TOMORROW...DAYTIME TEMPERATURES WILL BEGIN THE DAY BELOW FREEZING...IN A WINTRY MIX...BUT RISE TO THE MID 30S TO MID 40S DURING THE AFTERNOON. ICE GROWTH SHOULD SLOW AFTER TODAY. QPF OF AROUND 0.35 INCHES IS LIKELY TOMORROW...PART OF WHICH WILL FALL AS FREEZING RAIN AND SLEET. IT SHOULD HAVE NO IMMEDIATE SHORT TERM HYDROLOGIC IMPACTS AND NO HYDRO ISSUES ARE ANTICIPATED THROUGH THE NEXT FEW DAYS. 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...WINTER WEATHER ADVISORY FROM 4 AM TO NOON EST MONDAY FOR CTZ001-013. NY...WINTER WEATHER ADVISORY FROM 4 AM TO NOON EST MONDAY FOR NYZ038>040-047>054-058>061-063>066. WINTER WEATHER ADVISORY FROM 4 AM TO 6 PM EST MONDAY FOR NYZ032-033-041>043-082>084. MA...WINTER WEATHER ADVISORY FROM 4 AM TO NOON EST MONDAY FOR MAZ025. WINTER WEATHER ADVISORY FROM 4 AM TO 6 PM EST MONDAY FOR MAZ001. VT...WINTER WEATHER ADVISORY FROM 4 AM TO 6 PM EST MONDAY FOR VTZ013>015. && $$ SYNOPSIS...NAS NEAR TERM...KL/NAS SHORT TERM...NAS LONG TERM...BGM AVIATION...KL HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
210 PM CST SAT FEB 9 2013 .DISCUSSION... ISSUED 210 PM CST SAT FEB 9 2013 PESKY LOW CLOUDS WHICH HAVE PLAGUED THE AREA RECENTLY FINALLY HAVE BEEN SIGNIFICANTLY ERODING OVER THE LAST SEVERAL HOURS. EARLY AFTERNOON SATELLITE IMAGERY SHOWING THEM MAINLY CONFINED TO AREAS FROM THE ILLINOIS RIVER EAST TO CHAMPAIGN...ALTHOUGH THE REST OF THESE CLOUDS SHOULD BE GONE BY LATE AFTERNOON. NOT MUCH BREAK IN THE CLOUDS EXPECTED...AS MID AND HIGH CLOUDS WERE RAPIDLY ADVANCING IN FROM THE SOUTHWEST. LARGE UPPER LOW SLOWLY ADVANCING THROUGH THE 4 CORNERS REGION AND STILL ON TARGET TO AFFECT OUR WEATHER LATE TONIGHT INTO EARLY NEXT WEEK. SHORT TERM...TONIGHT THROUGH MONDAY... MORNING MODELS REMAIN IN GOOD AGREEMENT WITH LIFTING THE UPPER LOW INTO THE UPPER MISSISSIPPI VALLEY BY SUNDAY EVENING. SHOWERS ON THE INCREASE ACROSS OKLAHOMA THIS AFTERNOON AND WILL BE ADVECTING NORTHEAST TONIGHT AHEAD OF INTENSIFYING CYCLONE OVER THE PLAINS. A LOT OF DRY AIR IN THE LOWER LEVELS NEEDS TO BE OVERCOME IN OUR AREA...BUT RAP MODEL SOUNDINGS SHOW THE COLUMN MOISTENED UP IN SPRINGFIELD BY 2 AM AND THE NORTHEASTERN CWA AROUND 4-5 AM. HAVE INTRODUCED SOME SLIGHT CHANCE POPS IN THE FAR SOUTHWEST LATE THIS EVENING...BUT HIGHER OVERNIGHT POPS REMAIN AFTER MIDNIGHT. HIGHEST POPS DURING THE PERIOD WILL BE ON SUNDAY MORNING...WITH A RAPID ENDING OF THE RAIN FROM WEST TO EAST DURING THE AFTERNOON. WILL LINGER SOME SLIGHT CHANCE POPS INTO THE EVENING EAST OF I-57. WINDS ARE ALSO A CONCERN DURING THE PERIOD. PRESSURE GRADIENT TIGHTENS OVERNIGHT AS THE SURFACE LOW LIFTS NORTHEAST TO AROUND OMAHA BY LATE SUNDAY MORNING. WILL LIKELY SEE SOME GUSTS OF AROUND 30-35 MPH LATE MORNING THROUGH MID AFTERNOON. WINDS WILL REMAIN FAIRLY BREEZY AS THEY SWING AROUND TOWARD THE SOUTHWEST OR WEST SUNDAY NIGHT...THEN GUSTS OF 30-40 MPH LIKELY AGAIN ON MONDAY. HIGHEST GUSTS SHOULD BE ALONG AND NORTH OF THE I-74 CORRIDOR... CLOSER TO THE SURFACE LOW. LONG TERM...TUESDAY THROUGH SATURDAY... SOUTHERN BRANCH OF THE JET STREAM STILL LOOKS TO BE THE ACTIVE ONE MOST OF THIS WEEK...AS ANOTHER LOW IS DUG OUT OF THE DEEP TROUGH IN THE SOUTHWEST U.S. AND MOVES EASTWARD TOWARD THE GULF COAST. LONGER RANGE MODELS KEEP ANY OVERRUNNING PRECIP JUST TO OUR SOUTH LATE TUESDAY NIGHT AND WEDNESDAY AS THE SURFACE LOW LIFTS TOWARD THE MID-ATLANTIC COAST. MAIN FEATURE OF CONCERN IN THE EXTENDED IS THE CARVING OUT OF A DEEP TROUGH OVER THE CENTER OF THE NATION LATE THIS WEEK...MARKING A PERIOD OF COLDER WEATHER WHICH WILL BEGIN FRIDAY AND LAST MUCH OF THE WEEKEND. THE GFS AND ECMWF MODELS BOTH FORM A SURFACE REFLECTION IN THE TROUGH...BUT THE GFS IS A LOT STRONGER AND FURTHER NORTH WITH ANY PRECIPITATION. SLIGHT CHANCE POPS ARE STILL WARRANTED LATE IN THE WEEK DUE TO THE UNCERTAINTY. GEELHART && .AVIATION... ISSUED 1146 AM CST SAT FEB 9 2013 MVFR OVERCAST WILL CONTINUE TO ERODE FROM THE E/SE THIS AFTERNOON...AS SOUTHEASTERLY LOW-LEVEL FLOW PUSHES CLEARING LINE CURRENTLY ACROSS EAST-CENTRAL ILLINOIS SLOWLY WESTWARD. BASED ON SATELLITE TIMING TOOLS...CLOUDS WILL SCATTER AT KCMI BY 20Z...THEN FURTHER WEST TO KDEC BY AROUND 22Z. FURTHER WEST...THINK LOW CLOUDS WILL PERSIST UNTIL THEY ARE GRADUALLY MIXED OUT/PUSHED NORTHWARD EARLY THIS EVENING. IN THE MEANTIME...MID/HIGH CLOUDS ASSOCIATED WITH THE NEXT APPROACHING SYSTEM WILL QUICKLY SPREAD ACROSS THE AREA DURING THE EVENING. 12Z NAM FORECAST SOUNDINGS SUGGEST LOW CLOUDS WILL BE REPLACED BY A 12000FT OVERCAST BETWEEN 00Z AND 03Z. AS PROFILE SLOWLY MOISTENS...CLOUDS WILL LOWER AND SHOWERS WILL BEGIN TO DEVELOP FROM SOUTHWEST TO NORTHEAST AFTER MIDNIGHT. HAVE INITIALLY INCLUDED A 4-HOUR TEMPO GROUP FOR VFR CEILINGS AND SCATTERED SHOWERS BEFORE INTRODUCING PREDOMINANT RAIN TOWARD DAWN. BASED ON NAM/GFS SOUNDINGS...STEADY RAIN WILL BEGIN AT KSPI BY 10Z...THEN FURTHER NORTHEAST TO KCMI BY 13Z. CEILINGS WILL BE A BIT TRICKY...BUT WILL GO WITH LOW MVFR AT MOST SITES. WILL ONLY CARRY IFR CEILINGS LESS THAN 1000FT AT KBMI FOR NOW. WINDS WILL INITIALLY BE FROM THE S/SE AT 10 TO 15KT THIS AFTERNOON AND EVENING...THEN WILL INCREASE TO 15 TO 25KT LATE TONIGHT INTO SUNDAY. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1129 PM CST FRI FEB 8 2013 .DISCUSSION... ISSUED 830 PM CST FRI FEB 8 2013 LOW LEVEL CLOUD COVER CONTINUES TO HOLD OVER THE AREA THIS EVENING WITH A FEW BREAKS STARTING TO SHOW UP OVER PARTS OF NW INDIANA AND NORTH CENTRAL IL. HOWEVER...A LARGE BAND OF HIGH LEVEL CLOUDS WAS ALREADY STREAKING EAST INTO THE MID MISSISSIPPI VALLEY EARLY THIS EVENING AHEAD OF OUR NEXT WEATHER SYSTEM PUSHING OUT OF THE WEST COAST. 00Z ILX SOUNDING STILL SHOWING A RATHER STRONG SUBSIDENCE INVERSION ABOVE 925 MB WITH A VERY SHALLOW MOIST LAYER NOTED JUST BELOW THE INVERSION. THE MOISTURE DEPTH HAS DECREASED SIGNIFICANTLY FROM THIS MORNING WHICH OFFERS SOME HOPE FOR A DECREASE IN THE STRATOCUMULUS OVER OUR AREA OVERNIGHT AND INTO SATURDAY MORNING. SURFACE HIGH PRESSURE TO OUR NORTH WILL GRADUALLY WORK TO OUR EAST OVERNIGHT WITH THE VAD WIND PROFILES ALREADY SHOWING LOW LVL WINDS TURNING MORE ESE OUT OVER WEST CENTRAL IL. CURRENT FORECAST HAS A GOOD HANDLE ON THE TRENDS THIS EVENING AND OVERNIGHT...SO OTHER THAN SOME TWEAKS TO THE EARLY EVENING SKY COVER AND HOURLY TEMPERATURES...NO SIGNIFICANT CHANGES WERE MADE TO THE GRIDS THAT WOULD REQUIRE AN UPDATE AT THIS TIME. && .AVIATION... ISSUED 1120 PM CST FRI FEB 8 2013 MAIN FORECAST CHALLENGE THIS PERIOD WILL BE WITH THE PERSISTENT MVFR CIGS AND WHETHER WE SEE ANY SIGNIFICANT BREAKS DEVELOP IN THE CLOUDS SATURDAY MORNING. HI-RES FORECAST SOUNDINGS CONTINUE TO INDICATE SOME EROSION OF THE LOW LEVEL MOISTURE TRAPPED BELOW A RATHER STRONG SUBSIDENCE INVERSION. SEEING SOME BREAKS ACRS FAR WEST CENTRAL INDIANA AND EXTREME EASTERN IL LATE THIS EVENING WITH THE AREA OF SCATTERED TO BKN CIGS TO OUR NORTH EARLIER IN THE EVENING NOW PUSHING BACK TO THE NNW AS BOUNDARY LAYER WINDS HAVE SHIFTED INTO THE SOUTH. WILL CONTINUE TO CARRY THE MVFR CIGS OVERNIGHT WITH BASES AROUND 1500 FEET. WILL CONTINUE FROM THE PREVIOUS FORECAST IN INTRODUCING SCT-BKN CIGS STARTING AROUND 18Z...WITH SOME HIGH LEVEL CLOUDS (AROUND 20000-25000 FEET). THE NEXT WEATHER SYSTEM WILL START TO SPREAD MID LEVEL CLOUDS INTO OUR AREA SATURDAY EVENING BUT FOR NOW WILL KEEP ANY MENTION OF SHOWERS OUT OF THE CURRENT TAFS. IT APPEARS THAT IF WE DID SEE ANY RAINFALL AT PIA OR SPI...IT WOULD BE CLOSER TO 12Z SUNDAY. WINDS WILL CONTINUE TO SLOWLY VEER INTO A SOUTHEAST DIRECTION THIS MORNING AND CONTINUE OUT OF THE SOUTHEAST THRU THE REMAINDER OF THE FORECAST PERIOD. SPEEDS WILL BE LESS THAN 10 KTS TONIGHT...AND INCREASE TO BETWEEN 10 AND 15 KTS DURING THE DAY SATURDAY. SMITH && .PREV DISCUSSION... ISSUED 242 PM CST FRI FEB 8 2013 HIGH PRESSURE RIDGING CURRENTLY EXTENDING SOUTHWESTWARD FROM LAKE SUPERIOR TOWARD OKLAHOMA/ARKANSAS. HAVE SEEN SOME PERIODIC THINNING OF THE STRATOCUMULUS DECK IN THE EASTERN CWA...WITH SOME MORE SIGNIFICANT EROSION COMING IN FROM WISCONSIN AND SOUTHWEST MISSOURI. UPPER ANALYSIS AND WATER VAPOR IMAGERY SHOWING A LARGE CUTOFF LOW DROPPING SOUTHWARD THROUGH CALIFORNIA...AND THIS FEATURE WILL PLAY A SIGNIFICANT ROLE IN OUR WEATHER DURING THE WEEKEND. INITIAL FORECAST CHALLENGE WILL BE WITH THE CLOUD COVER OVERNIGHT...OTHERWISE THE FOCUS WILL BE ON THE RAIN EXPECTED DURING THE SECOND HALF OF THE WEEKEND. SHORT TERM...TONIGHT THROUGH MONDAY... CLOUD FORECAST WILL BE TRICKY OVERNIGHT. MOST OF THE MODELS ARE STRUGGLING SOMEWHAT WITH THE EXISTING COVERAGE. THE HRRR...WHICH IS FAIRLY CLOSE NOW...FILLS ANY GAPS BACK IN THIS EVENING. THE NAM THINKS ANYTHING WEST OF THE MISSISSIPPI RIVER SHOULD BE CLEAR ALREADY AND ERODES THE REST OF IT BY EARLY EVENING. THE RAP 925 MB HUMIDITY APPEARS FAIRLY CLOSE RIGHT NOW AND SHOWS GRADUAL EROSION FROM THE NORTH AND SOUTH THROUGH THE EVENING...BUT ITS FORECAST SOUNDINGS SHOW THE INVERSION AT 950 MB REMAINING RATHER TIGHT THROUGH THE NIGHT. HAVE USED A BLEND OF THE RAP 925 MB HUMIDITY AND THE MOS GUIDANCE TO COME UP WITH THE SKY GRIDS...WHICH SHOW SKIES BECOMING PARTLY CLOUDY AFTER MIDNIGHT. HIGH PRESSURE RIDGE TO CONTINUE PUSHING EASTWARD THROUGH SATURDAY...WITH WINDS COMING BACK AROUND TO THE SOUTHEAST BY LATE AFTERNOON. IN THE MEANTIME...THE MODELS ARE IN FAIRLY GOOD AGREEMENT IN LIFTING THE UPPER LOW INTO SOUTHEAST SOUTH DAKOTA BY MIDDAY SUNDAY AND THE ASSOCIATED CYCLONE BECOMING VERTICALLY STACKED DURING THE PROCESS. NOT MUCH CHANGE WAS NEEDED IN THE GRIDS FOR THE RAIN TIMING LATE SATURDAY NIGHT THROUGH SUNDAY...BUT HAVE BUMPED UP POP VALUES A LITTLE MORE. THE ASSOCIATED FRONTAL BOUNDARY AND BACK EDGE OF THE RAIN WILL RAPIDLY SWEEP EASTWARD DURING SUNDAY EVENING...AND SHOULD BE OUT OF THE AREA BEFORE TEMPERATURES GET COLD ENOUGH FOR ANY SNOW. SOUTHERLY WINDS ON SUNDAY WILL GUST TO AROUND 30 MPH OR SO...AND WITH THE LOW SLOW TO EXIT THE AREA...AM EXPECTING ANOTHER WINDY DAY ON MONDAY WITH WESTERLY WINDS GUSTING TO 30 MPH OR SO. THE HIGHER WIND GUSTS ON MONDAY WILL BE NORTH OF I-72...CLOSER TO THE LOW. LONG TERM...TUESDAY THROUGH FRIDAY... THE TRAILING END OF THE FRONT WILL GET HUNG UP ALONG THE GULF COAST EARLY NEXT WEEK...AND WILL INTERACT WITH AN UPPER TROUGH MOVING ALONG THE SOUTHERN JET STREAM. THIS WILL EFFECTIVELY CUT OFF ANY MOISTURE ADVECTION THIS FAR NORTH...WITH DRY CONDITIONS EXPECTED WITH THE NEXT TROUGH MOVING THROUGH THE NORTHERN STREAM ON WEDNESDAY. LATE IN THE WEEK...THE LONGER RANGE MODELS BEGIN TO DIVERGE. THE GFS IS MUCH MORE AGGRESSIVE IN DIGGING A TROUGH OVER THE CENTRAL CONUS...CUTTING OFF AN UPPER LOW WHICH WOULD DRIFT INTO ILLINOIS ON SATURDAY. THIS WOULD BE A WETTER AND COLDER SCENARIO FOR US...VERSUS THE BROADER LONG WAVE TROUGH OF THE ECMWF. HAVE LIMITED ANY POPS AT THE END OF THE WEEK TO THE SLIGHT CHANCE RANGE FOR NOW. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
932 PM EST SUN FEB 10 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 215 PM EST SUN FEB 10 2013 A STRONG OCCLUDED SYSTEM WILL LIFT NORTHEAST ACROSS CENTRAL INDIANA LATE TONIGHT WITH THE RAIN EXPECTED TO END IN ITS WAKE. THEN...HIGH PRESSURE WILL BUILD IN FROM THE PLAINS AND SOUTHERN STATES THROUGH TUESDAY ALLOWING FOR DRY WEATHER AND TEMPERATURES CLOSER TO SEASONABLE. A SOUTHERN SYSTEM WILL BRING A CHANCE OF RAIN OR SNOW TO FAR SOUTH CENTRAL INDIANA TUESDAY NIGHT AND WEDNESDAY. THE NEXT CHANCE OF PRECIPITATION AFTER THAT WILL BE THURSDAY NIGHT THROUGH SATURDAY WITH RAIN OR SNOW POSSIBLE AS A LOW PRESSURE SYSTEM PIVOTS ACROSS THE LOWER GREAT LAKES. ABOVE NORMAL TEMPERATURES ON THURSDAY AHEAD OF THE SYSTEM WILL GIVE WAY TO BELOW NORMAL TEMPERATURES LATE IN THE WEEKEND BEHIND AN ASSOCIATED COLD FRONT. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 719 PM EST SUN FEB 10 2013 LOWERED POPS TO LOW CHANCE/SLIGHT CHANCE ACROSS THE AREA BASED ON RADAR MOSAIC AND HRRR FIELDS FOR THE NEXT SEVERAL HOURS. SOUNDINGS ARE LOOKING MORE LIKE SPRINKLES/DRIZZLE POSSIBLE FOR THE NEXT FEW HOURS AND THEN DRY WITH CLEARING SKIES AS A DRY SLOT CURRENTLY OVER MISSOURI/WESTERN ILLINOIS MOVES THROUGH THE AREA. WIND GUSTS COULD INCREASE A BIT WITH THE ARRIVAL OF THE DRY SLOT AND COULD MAX OUT AROUND 40 MPH. GOING LOWS IN THE MIDDLE 30S TO AROUND 40 SEEM A LITTLE COOL BUT STILL COULD SEE A GOOD DROP WITH CLOUDS BREAKING FROM THE DRY SLOT SO WILL LEAVE ALONE FOR NOW. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... ISSUED AT 215 PM EST SUN FEB 10 2013 MAIN CHALLENGE TO THE FORECAST WILL BE WINDS AND CLOUD COVER MONDAY ALONG WITH RESULTANT TEMPERATURES. ANOTHER MAIN ISSUE IS WHETHER TO BRING ANY POPS IN TUESDAY NIGHT AND WEDNESDAY AND IF SO HOW FAR NORTH TO BRING THEM AS AS MODELS ARE ALL OVER THE PLACE ON A WEAK SOUTHERN SURFACE SYSTEM WITH THE 12Z NAM BRINGING THIS SYSTEM AS FAR NORTH AS NORTHERN KENTUCKY BY 00Z THURSDAY WITH QPF ACROSS ALL OF THE FORECAST AREA WEDNESDAY. AND AT THE OTHER SPECTRUM THE GEM...ECMWF AND GFS HAVE IT WELL SOUTH NEAR THE GULF WITH QPF ONLY ACROSS OUR FAR SOUTH MAINLY WEDNESDAY. THE NAM IS AN OUTLIER WITH A SLOWER AND MUCH STRONGER UPPER SYSTEM AS IT CLOSES INTO AN UPPER LOW AND MOVES INTO SOUTHWESTERN INDIANA BY 00Z THURSDAY WHICH IS THE MAIN REASON FOR ITS FURTHER NORTH SURFACE LOW TRACK AND RESULT QPF. PER HPC HEMISPHERIC DISCUSSION THE NAM SOLUTION REGARDING A STRONGER LOW IS PLAUSIBLE BUT WITH ALL THE OTHER MODELS KEEPING THE SURFACE LOW WELL SOUTH...FAVOR THAT SOLUTION AND ALSO FAVOR A SLOWER SOLUTION PER MODEL TRENDS THAT WOULD FAVOR HOLDING OFF ON POPS UNTIL AFTER 06Z WEDNESDAY SOUTH CENTRAL AND CONTINUING THROUGH THE DAY WEDNESDAY. SMALL POPS ALSO LOOK LIKE THE WAY TO GO FOR NOW ESPECIALLY WITH THE UNCERTAINTY OF TIMING AND STRENGTH OF THE SYSTEM. GETTING BACK TO MONDAY...PLENTY OF LOW LEVEL MOISTURE IS PROGGED TO LINGER AS THE OCCLUDED LOW CENTER MOVES EAST ACROSS SOUTHERN ONTARIO. IN ADDITION...STRONG COLD AIR ADVECTION WILL BE TAKING PLACE. THUS...THINK THERE WILL BE A GOOD DEGREE OF CLOUD COVER AROUND AND FAVOR ADDING MORE CLOUD COVER THAN ALLBLEND AND KEEPING TEMPERATURES AT OR BELOW SIMILAR MOS. BUFKIT SUGGESTS WINDS TO 30 KNOTS AND GUSTS TO OVER 35 KNOTS POSSIBLE. SO...IT IS LOOKING LIKE NEAR ADVISORY CRITERIA. WILL COORDINATE AND MAKE LAST MINUTE DECISION ON WHETHER TO ISSUE AN ADVISORY OR A SPECIAL WEATHER STATEMENT. MONDAY NIGHT...SURFACE HIGH PRESSURE WILL BUILD IN FROM THE PLAINS AND SOUTHERN STATES...BUT MODEL TIME SECTIONS AND SOUNDINGS STILL HOLD ON TO A DECENT AMOUNT OF LOW LEVEL MOISTURE. SO...NOT EXPECTING FULL CLEARING...BUT SHOULD SEE SOME BREAKS. MOS TEMPERATURES VERY CLOSE...SO WILL STICK CLOSE TO THEM. FINALLY...TUESDAY...THE LOW LEVELS DRY UP WITH ONLY SOME HIGH CLOUDS AHEAD OF THE AFOREMENTIONED UPPER SYSTEM EXPECTED. WILL LEAN TOWARDS THE SLIGHTLY WARMER 12Z GFS MOS DUE TO THE LACK OF LOW CLOUDS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... ISSUED AT 244 PM EST SUN FEB 10 2013 THERE IS SIGNIFICANT VARIABILITY IN EXTENDED PERIOD AS SEVERAL LITTLE DISTURBANCES ROTATE AROUND A VERY BROAD UPPER LEVEL LOW. SO...WILL NOT DEVIATE MUCH FROM LATEST INITIALIZATION NUMBERS. THERE WILL BE PERIODIC CHANCES FOR PRECIP FROM THURSDAY NIGHT THROUGH SUNDAY...BUT PRECIP WILL FLUCTUATE BETWEEN RAIN/WINTRY MIX/SNOW UNTIL COLDER AIR SETTLES IN NEXT WEEKEND. WILL STICK WITH ALLBLEND IN REGARD TO TEMPS AND NOT DEVIATE. && .AVIATION /DISCUSSION FOR 110300Z TAF UPDATE/... ISSUED AT 932 PM EST SUN FEB 10 2013 MAKING SOME MINOR ADJUSTMENTS TO WIND DIRECTION AND GUSTS BASED ON OBS. ALSO DROPPED THE LLWS MENTION AT BOTH KBMG AND KIND...BUT PLAN ON HOLDING ONTO IT AT KHUF AND KLAF AS CRITERIA MAY BE JUST MET FOR ANOTHER COUPLE HOURS. IFR CEILINGS HAVE NOT COME TO PASS SO FAR AT THE WESTERN TERMINALS AND HAVE BACKED OFF THE CEILINGS TO A PREVAILING LOW MVFR THROUGH 06Z. 00Z DISCUSSION FOLLOWS. WIND GUSTS AND CEILINGS WILL BE ISSUES THROUGHOUT THE FORECAST PERIOD. STRONG LOW PRESSURE CENTERED OVER NORTHERN IOWA EARLY THIS EVENING WILL MOVE NORTHEAST INTO THE GREAT LAKES BY MONDAY AFTERNOON. TIGHT PRESSURE GRADIENT IN PLACE WILL BRING INCREASINGLY GUSTY WINDS TO THE REGION OVERNIGHT...AND ESPECIALLY MONDAY. WIDESPREAD RAIN HAS MOVED EAST OF ALL TERMINALS AND OUTSIDE OF A FEW SPRINKLES THIS EVENING...NOT ANTICIPATING ANY ADDITIONAL RAINFALL. CEILINGS AND LOW LEVEL WIND SHEAR ARE ISSUES RIGHT OUT OF THE GATE AS MVFR CEILINGS STEADILY EXPANDING ACROSS CENTRAL INDIANA. SEVERAL LOCATIONS ACROSS CENTRAL ILLINOIS EXPERIENCING CEILINGS BELOW 1000FT AND EXPECT THIS TO IMPACT KHUF AND KLAF THROUGH THE EVENING. LOWER CONFIDENCE IN IFR CEILINGS REACHING EITHER KBMG OR KIND AT THIS POINT BUT WILL MONITOR. HAVE ALSO INTRODUCED LOW LEVEL WIND SHEAR THROUGH THE EVENING AS LAPS SOUNDINGS INDICATING 55-60KTS WINDS PRESENT AT ABOUT 2-3KFT. AS WINDS SLACKEN ALOFT JUST A BIT LATER TONIGHT AND SURFACE FLOW VEERS TO A MORE SOUTHWEST DIRECTION...THE LLWS CONCERN WILL DIMINISH. WELL DEFINED DRY SLOT ON THE SATELLITE IMAGERY WILL EXPAND INTO CENTRAL INDIANA AFTER 06Z AND SHOULD PROVIDE A PERIOD OF SEVERAL HOURS WITH PARTLY CLOUDY SKIES AND VFR CONDITIONS FOR ALL TERMINALS LASTING INTO MID MORNING MONDAY. WIND GUSTS MAY APPROACH OR EXCEED 30KTS LATE TONIGHT INTO MONDAY MORNING. AS COLD POOL ALOFT EXPANDS ACROSS THE REGION...CLOUDS WILL QUICKLY FILL BACK IN BY MIDDAY AND REMAIN IN ABUNDANCE ACROSS CENTRAL INDIANA THROUGH THE REMAINDER OF THE DAY. AT THIS POINT...ONLY LOCATION THAT MIGHT HAVE TO CONTEND WITH MVFR CEILINGS ON MONDAY WILL BE KLAF AS MODEL SOUNDINGS SUPPORTIVE OF DEEPER LOW LEVEL MOISTURE. DESPITE THE CLOUD COVER...ANTICIPATE STRONG WIND GUSTS MONDAY AFTERNOON AT ALL TERMINALS FROM 260-270 DEGREES. SUSTAINEDS AT 25-30KTS ARE LIKELY WITH GUSTS APPROACHING 40KTS. WINDS WILL BEGIN TO DIMINISH AFTER SUNSET MONDAY. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...CP SHORT TERM...MK LONG TERM....TDUD AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
734 PM EST SUN FEB 10 2013 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 215 PM EST SUN FEB 10 2013 A STRONG OCCLUDED SYSTEM WILL LIFT NORTHEAST ACROSS CENTRAL INDIANA LATE TONIGHT WITH THE RAIN EXPECTED TO END IN ITS WAKE. THEN...HIGH PRESSURE WILL BUILD IN FROM THE PLAINS AND SOUTHERN STATES THROUGH TUESDAY ALLOWING FOR DRY WEATHER AND TEMPERATURES CLOSER TO SEASONABLE. A SOUTHERN SYSTEM WILL BRING A CHANCE OF RAIN OR SNOW TO FAR SOUTH CENTRAL INDIANA TUESDAY NIGHT AND WEDNESDAY. THE NEXT CHANCE OF PRECIPITATION AFTER THAT WILL BE THURSDAY NIGHT THROUGH SATURDAY WITH RAIN OR SNOW POSSIBLE AS A LOW PRESSURE SYSTEM PIVOTS ACROSS THE LOWER GREAT LAKES. ABOVE NORMAL TEMPERATURES ON THURSDAY AHEAD OF THE SYSTEM WILL GIVE WAY TO BELOW NORMAL TEMPERATURES LATE IN THE WEEKEND BEHIND AN ASSOCIATED COLD FRONT. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 719 PM EST SUN FEB 10 2013 LOWERED POPS TO LOW CHANCE/SLIGHT CHANCE ACROSS THE AREA BASED ON RADAR MOSAIC AND HRRR FIELDS FOR THE NEXT SEVERAL HOURS. SOUNDINGS ARE LOOKING MORE LIKE SPRINKLES/DRIZZLE POSSIBLE FOR THE NEXT FEW HOURS AND THEN DRY WITH CLEARING SKIES AS A DRY SLOT CURRENTLY OVER MISSOURI/WESTERN ILLINOIS MOVES THROUGH THE AREA. WIND GUSTS COULD INCREASE A BIT WITH THE ARRIVAL OF THE DRY SLOT AND COULD MAX OUT AROUND 40 MPH. GOING LOWS IN THE MIDDLE 30S TO AROUND 40 SEEM A LITTLE COOL BUT STILL COULD SEE A GOOD DROP WITH CLOUDS BREAKING FROM THE DRY SLOT SO WILL LEAVE ALONE FOR NOW. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... ISSUED AT 215 PM EST SUN FEB 10 2013 MAIN CHALLENGE TO THE FORECAST WILL BE WINDS AND CLOUD COVER MONDAY ALONG WITH RESULTANT TEMPERATURES. ANOTHER MAIN ISSUE IS WHETHER TO BRING ANY POPS IN TUESDAY NIGHT AND WEDNESDAY AND IF SO HOW FAR NORTH TO BRING THEM AS AS MODELS ARE ALL OVER THE PLACE ON A WEAK SOUTHERN SURFACE SYSTEM WITH THE 12Z NAM BRINGING THIS SYSTEM AS FAR NORTH AS NORTHERN KENTUCKY BY 00Z THURSDAY WITH QPF ACROSS ALL OF THE FORECAST AREA WEDNESDAY. AND AT THE OTHER SPECTRUM THE GEM...ECMWF AND GFS HAVE IT WELL SOUTH NEAR THE GULF WITH QPF ONLY ACROSS OUR FAR SOUTH MAINLY WEDNESDAY. THE NAM IS AN OUTLIER WITH A SLOWER AND MUCH STRONGER UPPER SYSTEM AS IT CLOSES INTO AN UPPER LOW AND MOVES INTO SOUTHWESTERN INDIANA BY 00Z THURSDAY WHICH IS THE MAIN REASON FOR ITS FURTHER NORTH SURFACE LOW TRACK AND RESULT QPF. PER HPC HEMISPHERIC DISCUSSION THE NAM SOLUTION REGARDING A STRONGER LOW IS PLAUSIBLE BUT WITH ALL THE OTHER MODELS KEEPING THE SURFACE LOW WELL SOUTH...FAVOR THAT SOLUTION AND ALSO FAVOR A SLOWER SOLUTION PER MODEL TRENDS THAT WOULD FAVOR HOLDING OFF ON POPS UNTIL AFTER 06Z WEDNESDAY SOUTH CENTRAL AND CONTINUING THROUGH THE DAY WEDNESDAY. SMALL POPS ALSO LOOK LIKE THE WAY TO GO FOR NOW ESPECIALLY WITH THE UNCERTAINTY OF TIMING AND STRENGTH OF THE SYSTEM. GETTING BACK TO MONDAY...PLENTY OF LOW LEVEL MOISTURE IS PROGGED TO LINGER AS THE OCCLUDED LOW CENTER MOVES EAST ACROSS SOUTHERN ONTARIO. IN ADDITION...STRONG COLD AIR ADVECTION WILL BE TAKING PLACE. THUS...THINK THERE WILL BE A GOOD DEGREE OF CLOUD COVER AROUND AND FAVOR ADDING MORE CLOUD COVER THAN ALLBLEND AND KEEPING TEMPERATURES AT OR BELOW SIMILAR MOS. BUFKIT SUGGESTS WINDS TO 30 KNOTS AND GUSTS TO OVER 35 KNOTS POSSIBLE. SO...IT IS LOOKING LIKE NEAR ADVISORY CRITERIA. WILL COORDINATE AND MAKE LAST MINUTE DECISION ON WHETHER TO ISSUE AN ADVISORY OR A SPECIAL WEATHER STATEMENT. MONDAY NIGHT...SURFACE HIGH PRESSURE WILL BUILD IN FROM THE PLAINS AND SOUTHERN STATES...BUT MODEL TIME SECTIONS AND SOUNDINGS STILL HOLD ON TO A DECENT AMOUNT OF LOW LEVEL MOISTURE. SO...NOT EXPECTING FULL CLEARING...BUT SHOULD SEE SOME BREAKS. MOS TEMPERATURES VERY CLOSE...SO WILL STICK CLOSE TO THEM. FINALLY...TUESDAY...THE LOW LEVELS DRY UP WITH ONLY SOME HIGH CLOUDS AHEAD OF THE AFOREMENTIONED UPPER SYSTEM EXPECTED. WILL LEAN TOWARDS THE SLIGHTLY WARMER 12Z GFS MOS DUE TO THE LACK OF LOW CLOUDS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... ISSUED AT 244 PM EST SUN FEB 10 2013 THERE IS SIGNIFICANT VARIABILITY IN EXTENDED PERIOD AS SEVERAL LITTLE DISTURBANCES ROTATE AROUND A VERY BROAD UPPER LEVEL LOW. SO...WILL NOT DEVIATE MUCH FROM LATEST INITIALIZATION NUMBERS. THERE WILL BE PERIODIC CHANCES FOR PRECIP FROM THURSDAY NIGHT THROUGH SUNDAY...BUT PRECIP WILL FLUCTUATE BETWEEN RAIN/WINTRY MIX/SNOW UNTIL COLDER AIR SETTLES IN NEXT WEEKEND. WILL STICK WITH ALLBLEND IN REGARD TO TEMPS AND NOT DEVIATE. && .AVIATION /DISCUSSION FOR 110000Z TAF ISSUANCE/... ISSUED AT 625 PM EST SUN FEB 10 2013 WIND GUSTS AND CEILINGS WILL BE ISSUES THROUGHOUT THE FORECAST PERIOD. STRONG LOW PRESSURE CENTERED OVER NORTHERN IOWA EARLY THIS EVENING WILL MOVE NORTHEAST INTO THE GREAT LAKES BY MONDAY AFTERNOON. TIGHT PRESSURE GRADIENT IN PLACE WILL BRING INCREASINGLY GUSTY WINDS TO THE REGION OVERNIGHT...AND ESPECIALLY MONDAY. WIDESPREAD RAIN HAS MOVED EAST OF ALL TERMINALS AND OUTSIDE OF A FEW SPRINKLES THIS EVENING...NOT ANTICIPATING ANY ADDITIONAL RAINFALL. CEILINGS AND LOW LEVEL WIND SHEAR ARE ISSUES RIGHT OUT OF THE GATE AS MVFR CEILINGS STEADILY EXPANDING ACROSS CENTRAL INDIANA. SEVERAL LOCATIONS ACROSS CENTRAL ILLINOIS EXPERIENCING CEILINGS BELOW 1000FT AND EXPECT THIS TO IMPACT KHUF AND KLAF THROUGH THE EVENING. LOWER CONFIDENCE IN IFR CEILINGS REACHING EITHER KBMG OR KIND AT THIS POINT BUT WILL MONITOR. HAVE ALSO INTRODUCED LOW LEVEL WIND SHEAR THROUGH THE EVENING AS LAPS SOUNDINGS INDICATING 55-60KTS WINDS PRESENT AT ABOUT 2-3KFT. AS WINDS SLACKEN ALOFT JUST A BIT LATER TONIGHT AND SURFACE FLOW VEERS TO A MORE SOUTHWEST DIRECTION...THE LLWS CONCERN WILL DIMINISH. WELL DEFINED DRY SLOT ON THE SATELLITE IMAGERY WILL EXPAND INTO CENTRAL INDIANA AFTER 06Z AND SHOULD PROVIDE A PERIOD OF SEVERAL HOURS WITH PARTLY CLOUDY SKIES AND VFR CONDITIONS FOR ALL TERMINALS LASTING INTO MID MORNING MONDAY. WIND GUSTS MAY APPROACH OR EXCEED 30KTS LATE TONIGHT INTO MONDAY MORNING. AS COLD POOL ALOFT EXPANDS ACROSS THE REGION...CLOUDS WILL QUICKLY FILL BACK IN BY MIDDAY AND REMAIN IN ABUNDANCE ACROSS CENTRAL INDIANA THROUGH THE REMAINDER OF THE DAY. AT THIS POINT...ONLY LOCATION THAT MIGHT HAVE TO CONTEND WITH MVFR CEILINGS ON MONDAY WILL BE KLAF AS MODEL SOUNDINGS SUPPORTIVE OF DEEPER LOW LEVEL MOISTURE. DESPITE THE CLOUD COVER...ANTICIPATE STRONG WIND GUSTS MONDAY AFTERNOON AT ALL TERMINALS FROM 260-270 DEGREES. SUSTAINEDS AT 25-30KTS ARE LIKELY WITH GUSTS APPROACHING 40KTS. WINDS WILL BEGIN TO DIMINISH AFTER SUNSET MONDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MK NEAR TERM...CP SHORT TERM...MK LONG TERM....TDUD AVIATION...RYAN
AREA FORECAST DISCUSSION...CORRECTED
NWS QUAD CITIES IA IL
1139 PM CST FRI FEB 8 2013 .AVIATION... MVFR TO IFR CIGS EXPECTED TO CONTINUE THROUGH AT LEAST 09/15Z. CURRENTLY MVFR CIGS TO LOWER TO IFR AFTER 09/10Z...THEN INCREASE AGAIN. MOISTURE TRAPPED UNDER AN INVERSION WILL REMAIN THERE AS A SURFACE HIGH MOVES INTO THE GREAT LAKES TONIGHT. SOUTHERLY WINDS ON THE BACK SIDE OF THE HIGH SHOULD RESULT IN CLEARING DEVELOPING ACROSS KS/MO THAT BEGINS MOVING NORTH INTO IA/IL AFT 12Z/09. CONDITIONS SHOULD IMPROVE TO VFR BY 18Z/09. LIGHT AND VARIABLE WINDS TONIGHT TO SLOWLY INCREASE OUT OF THE SOUTHEAST AT 10-15KT AFTER 09/15Z. AFTER 10/03Z RAIN SHOWERS TO MOVE INTO THE AREA FROM THE SOUTHWEST...BUT SHOULD STAY OUT OF THE TERMINALS UNTIL AFTER 06Z TONIGHT. CIGS TO GRADUALLY LOWER DURING THE EVENING BUT TO REMAIN VFR THROUGH 06Z. ..LE.. && .PREV DISCUSSION... /ISSUED 252 PM CST FRI FEB 8 2013/ SYNOPSIS... 12Z UA ANALYSIS HAS TWO SEPARATE 850MB LOWS STARTING TO MERGE OVER THE MID ATLANTIC AREA WITH HIGH PRESSURE ACROSS THE PLAINS. SATELLITE TRENDS THROUGH MID AFTERNOON SHOW CLEARING OF THE LOW CLOUDS ACROSS MN/WI MOVING INTO PARTS OF ILLINOIS IN A SUBSIDENCE AREA. CLEARING OF THE LOW CLOUDS WAS ALSO OCCURRING ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY WHILE CLOUDS REMAIN ACROSS THE MID MISSISSIPPI VALLEY. 18Z SFC ANALYSIS HAS A LOW IN SOUTHWEST SOUTH DAKOTA WITH A WARM FRONT INTO NORTHEAST NEBRASKA. HIGH PRESSURE EXTENDED FROM WESTERN LAKE SUPERIOR INTO TEXAS. DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE GREAT LAKES AND PLAINS WITH 30S AND HIGHER OVER THE OHIO VALLEY AND DEEP SOUTH. SHORT TERM...TONIGHT AND SATURDAY... QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA TONIGHT AND SATURDAY AS HIGH PRESSURE MOVES INTO THE EASTERN GREAT LAKES. CLOUDS WILL HOLD ACROSS THE AREA FOR MUCH OF TONIGHT UNTIL RETURN FLOW DEVELOPS AND ALLOWS THE SUBSIDENCE ACROSS KS/MO TO MOVE NORTHWARD. CLOUDS ARE EXPECTED TO CLEAR FROM SOUTH TO NORTH FROM JUST PRIOR TO DAWN THROUGH SATURDAY MORNING ACROSS THE AREA. THERE ARE QUESTIONS AS TO WHETHER OR NOT THERE COULD BE ANY FOG DEVELOPMENT TONIGHT. IF IT WOULD OCCUR...IT SHOULD BE VERY PATCHY IN NATURE. THE RAP INITIALLY INDICATED SIGNIFICANT FOG DEVELOPMENT TONIGHT BUT MORE RECENT TRENDS HAVE BACKED OFF ON ANY FOG DEVELOPMENT. AREAS THAT ARE CLEAR THIS EVENING AND OVER THE SNOW FIELD SHOULD SEE TEMPERATURES IN THE TEENS AND POSSIBLY SOME SINGLE DIGITS. ELSEWHERE...TEMPERATURES ARE EXPECTED TO REMAIN IN THE LOW TO MID 20S. ABOVE NORMAL TEMPERATURES ARE EXPECTED ON SATURDAY. ..08.. LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY... DEEP SOUTHERLY FLOW WILL ALREADY BE IN PLACE SATURDAY EVENING...AND WITH MOISTURE RAPIDLY SURGING NORTH THROUGH THE EVENING AND OVERNIGHT...CLOUDS WILL BECOME WIDESPREAD AND OPAQUE EARLY ON...IF NOT ALREADY AT SUNSET IN MOST PLACES. WINDS WILL ALSO BE ON THE INCREASE THROUGH THE NIGHT....ALLOWING FOR TEMPERATURES TO REMAIN ABOVE FREEZING...EVEN AFTER A POSSIBLE EVENING DIP TO LOWS EARLY IN THE EVENING. THUS...DESPITE MODEL GUIDANCE SUGGESTING FREEZING RAIN OVERNIGHT...IT REALLY SEEMS UNLIKELY GIVEN OUR SNOW PACK ONLY OVER OUR FAR NORTH...AND THE INCREASING WAA AFTER AN ALREADY MILD DAY PRECEDING IT. FOR NOW...WILL ONLY MENTION THIS POTENTIAL IN THE FAR NORTH...OVER THE CURRENT SNOW AREA...BUT EVEN THERE THE THREAT FOR NEW ICE FORMATION FROM FREEZING RAIN SEEMS QUITE LOW. OTHERWISE...WAA OVERNIGHT SHOULD PRODUCE WIDESPREAD RAIN AFTER MIDNIGHT AS THE COLUMN SATURATES...WITH A BAND OF MODERATE RAIN WITH EMBEDDED THUNDER WORKING OVER THE AREA FROM SOUTH TO NORTH SUNDAY THROUGH EARLY AFTERNOON. RAINFALL OF 0.25 TO 0.50 IS LIKELY WITH SOME HIGHER POSSIBLE IN CONVECTION AND ANY TRAINING BANDED HEAVY RAINS. AFTER 3 PM...A DRY SLOT SHOULD AFFECT MOST LOCATIONS...WITH BREEZY/WINDY SOUTHWEST TO WEST WINDS WRAPPING IN. SOME SHOWERS MAY YET OCCUR IN THE NORTH HALF AS WRAP AROUND MOISTURE MOVES BACK IN DURING THE EVENING. SNOW SHOWERS ARE POSSIBLE LATE AND ON MONDAY MORNING. THERE SEEMS VERY LITTLE THREAT FOR ACCUMULATING SNOW WITH THIS STORM...AS MODELS NOW HAVE TEMPERATURES ABOVE FREEZING MONDAY IN THE DEEP MIXED OCCLUDED CYCLONE CIRCULATION. THE MILD AIR SHOULD CONTINUE THROUGH MID WEEK BEFORE A SIGNIFICANT CLIPPER OR WESTERLY SHORT WAVE MAY BRING ANOTHER SHOT AT RAIN OR SNOW TOWARD THURSDAY AND FRIDAY. THE MODELS ARE IN POOR AGREEMENT ON THIS WAVE BEYOND THAT IT EXISTS. THE GFS SHOWS A PERSISTENT SNOW...WHILE THE ECMWF SHOWS A GLANCING SHOT OF RAIN AND SNOW GOING MAINLY NORTH. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ LE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1138 PM CST FRI FEB 8 2013 .AVIATION... MVFR CONDITIONS EXPECTED TO CONTINUE THROUGH AT LEAST 09/15Z. MOISTURE TRAPPED UNDER AN INVERSION WILL REMAIN THERE AS A SURFACE HIGH MOVES INTO THE GREAT LAKES TONIGHT. SOUTHERLY WINDS ON THE BACK SIDE OF THE HIGH SHOULD RESULT IN CLEARING DEVELOPING ACROSS KS/MO THAT BEGINS MOVING NORTH INTO IA/IL AFT 12Z/09. CONDITIONS SHOULD IMPROVE TO VFR BY 18Z/09. LIGHT AND VARIABLE WINDS TONIGHT TO SLOWLY INCREASE OUT OF THE SOUTHEAST AT 10-15KT AFTER 09/15Z. AFTER 10/03Z RAIN SHOWERS TO MOVE INTO THE AREA FROM THE SOUTHWEST...BUT SHOULD STAY OUT OF THE TERMINALS UNTIL AFTER 06Z TONIGHT. CIGS TO GRADUALLY LOWER DURING THE EVENING BUT TO REMAIN VFR THROUGH 06Z. ..LE.. && .PREV DISCUSSION... /ISSUED 252 PM CST FRI FEB 8 2013/ SYNOPSIS... 12Z UA ANALYSIS HAS TWO SEPARATE 850MB LOWS STARTING TO MERGE OVER THE MID ATLANTIC AREA WITH HIGH PRESSURE ACROSS THE PLAINS. SATELLITE TRENDS THROUGH MID AFTERNOON SHOW CLEARING OF THE LOW CLOUDS ACROSS MN/WI MOVING INTO PARTS OF ILLINOIS IN A SUBSIDENCE AREA. CLEARING OF THE LOW CLOUDS WAS ALSO OCCURRING ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY WHILE CLOUDS REMAIN ACROSS THE MID MISSISSIPPI VALLEY. 18Z SFC ANALYSIS HAS A LOW IN SOUTHWEST SOUTH DAKOTA WITH A WARM FRONT INTO NORTHEAST NEBRASKA. HIGH PRESSURE EXTENDED FROM WESTERN LAKE SUPERIOR INTO TEXAS. DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE GREAT LAKES AND PLAINS WITH 30S AND HIGHER OVER THE OHIO VALLEY AND DEEP SOUTH. SHORT TERM...TONIGHT AND SATURDAY... QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA TONIGHT AND SATURDAY AS HIGH PRESSURE MOVES INTO THE EASTERN GREAT LAKES. CLOUDS WILL HOLD ACROSS THE AREA FOR MUCH OF TONIGHT UNTIL RETURN FLOW DEVELOPS AND ALLOWS THE SUBSIDENCE ACROSS KS/MO TO MOVE NORTHWARD. CLOUDS ARE EXPECTED TO CLEAR FROM SOUTH TO NORTH FROM JUST PRIOR TO DAWN THROUGH SATURDAY MORNING ACROSS THE AREA. THERE ARE QUESTIONS AS TO WHETHER OR NOT THERE COULD BE ANY FOG DEVELOPMENT TONIGHT. IF IT WOULD OCCUR...IT SHOULD BE VERY PATCHY IN NATURE. THE RAP INITIALLY INDICATED SIGNIFICANT FOG DEVELOPMENT TONIGHT BUT MORE RECENT TRENDS HAVE BACKED OFF ON ANY FOG DEVELOPMENT. AREAS THAT ARE CLEAR THIS EVENING AND OVER THE SNOW FIELD SHOULD SEE TEMPERATURES IN THE TEENS AND POSSIBLY SOME SINGLE DIGITS. ELSEWHERE...TEMPERATURES ARE EXPECTED TO REMAIN IN THE LOW TO MID 20S. ABOVE NORMAL TEMPERATURES ARE EXPECTED ON SATURDAY. ..08.. LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY... DEEP SOUTHERLY FLOW WILL ALREADY BE IN PLACE SATURDAY EVENING...AND WITH MOISTURE RAPIDLY SURGING NORTH THROUGH THE EVENING AND OVERNIGHT...CLOUDS WILL BECOME WIDESPREAD AND OPAQUE EARLY ON...IF NOT ALREADY AT SUNSET IN MOST PLACES. WINDS WILL ALSO BE ON THE INCREASE THROUGH THE NIGHT....ALLOWING FOR TEMPERATURES TO REMAIN ABOVE FREEZING...EVEN AFTER A POSSIBLE EVENING DIP TO LOWS EARLY IN THE EVENING. THUS...DESPITE MODEL GUIDANCE SUGGESTING FREEZING RAIN OVERNIGHT...IT REALLY SEEMS UNLIKELY GIVEN OUR SNOW PACK ONLY OVER OUR FAR NORTH...AND THE INCREASING WAA AFTER AN ALREADY MILD DAY PRECEDING IT. FOR NOW...WILL ONLY MENTION THIS POTENTIAL IN THE FAR NORTH...OVER THE CURRENT SNOW AREA...BUT EVEN THERE THE THREAT FOR NEW ICE FORMATION FROM FREEZING RAIN SEEMS QUITE LOW. OTHERWISE...WAA OVERNIGHT SHOULD PRODUCE WIDESPREAD RAIN AFTER MIDNIGHT AS THE COLUMN SATURATES...WITH A BAND OF MODERATE RAIN WITH EMBEDDED THUNDER WORKING OVER THE AREA FROM SOUTH TO NORTH SUNDAY THROUGH EARLY AFTERNOON. RAINFALL OF 0.25 TO 0.50 IS LIKELY WITH SOME HIGHER POSSIBLE IN CONVECTION AND ANY TRAINING BANDED HEAVY RAINS. AFTER 3 PM...A DRY SLOT SHOULD AFFECT MOST LOCATIONS...WITH BREEZY/WINDY SOUTHWEST TO WEST WINDS WRAPPING IN. SOME SHOWERS MAY YET OCCUR IN THE NORTH HALF AS WRAP AROUND MOISTURE MOVES BACK IN DURING THE EVENING. SNOW SHOWERS ARE POSSIBLE LATE AND ON MONDAY MORNING. THERE SEEMS VERY LITTLE THREAT FOR ACCUMULATING SNOW WITH THIS STORM...AS MODELS NOW HAVE TEMPERATURES ABOVE FREEZING MONDAY IN THE DEEP MIXED OCCLUDED CYCLONE CIRCULATION. THE MILD AIR SHOULD CONTINUE THROUGH MID WEEK BEFORE A SIGNIFICANT CLIPPER OR WESTERLY SHORT WAVE MAY BRING ANOTHER SHOT AT RAIN OR SNOW TOWARD THURSDAY AND FRIDAY. THE MODELS ARE IN POOR AGREEMENT ON THIS WAVE BEYOND THAT IT EXISTS. THE GFS SHOWS A PERSISTENT SNOW...WHILE THE ECMWF SHOWS A GLANCING SHOT OF RAIN AND SNOW GOING MAINLY NORTH. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ LE
AREA FORECAST DISCUSSION
NWS WICHITA KS
1200 PM CST SAT FEB 9 2013 .UPDATE... CHANGE THE TIMING OF THE PRECIPITATION BASED ON THE 12Z AND 15Z NWP AND CURRENT TRENDS. KICT 88D AND VISIBLE SATELLITE LOOP ENDING AT 1750Z SHOWS CONVECTIVE LOOKING PRECIPITATION/CLOUDS MOVING INTO SOUTH CENTRAL KANSAS. THE 15Z RAP IS PERFORM THE BEST WITH THIS PRECIPITATION AT THIS TIME. NO HRRR MODEL RUN AVAILABLE SINCE 08.21Z. WILL CONTINUE TREND OF BRINGING THE PRECIPITATION NORTHEAST INTO AND THROUGH THE FORECAST AREA. THIS SHOULD GRADUALLY INCREASE IN AREAL COVERAGE AND INTENSITY THIS EVENING AS LOW-LEVEL MOISTURE TRANSPORT INCREASES...AFTER 10.00Z. COOK && .AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU CONVECTIVE PRECIPITATION NOW STARTING ACROSS SOUTHCENTRAL KANSAS. THIS CONVECTION SHOULD MOVE NORTHEAST INTO CENTRAL KANSAS THIS AFTERNOON. NO SIGNIFICANT RESTRICTION TO VSBYS ARE ANTICIPATED. CIGS NEAR 1200 FEET IN CLOSE PROXIMITY TO THE PRECIPITATION. INSTABILITY LIMITED SO ONLY ISOLATED THUNDER POSSIBLE AFTER 20Z. WINDS WILL REMAIN SOUTH WITH THE STRONGEST WIND SPEEDS GUSTING TO 35 KNOTS AT KRSL AND KSLN. COLD FRONT MOVES THROUGH TONIGHT...SHIFTING WINDS TO THE WEST AT 09Z AT KRSL TO 13Z AT KCNU. WINDS SUNDAY WILL BE STRONG NORTHWESTERLY AT 25-35 KNOTS WITH GUSTS OVER 40 AT KRSL. COOK && .PREV DISCUSSION... /ISSUED 523 AM CST SAT FEB 9 2013/ AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN HAZARDS: STRONG SOUTHERLY WIND GUSTS TODAY-TONIGHT...THUNDERSTORM POTENTIAL WITH LOW CLOUDS TONIGHT. AS LOW PRESSURE DEVELOPS OVER EASTERN COLORADO...SOUTH- SOUTHEASTERLY WINDS WILL INCREASE TODAY WITH GUSTS 35-40 KT IN CENTRAL KS...AND AROUND 30 KT IN THE SOUTHEAST. A FEW SPRINKLES/LIGHT SHOWERS ARE POSSIBLE MIDDAY INTO THE AFTERNOON. A BAND OF SHOWERS/THUNDERSTORMS IS EXPECTED TO MOVE EASTWARD ACROSS THE REGION TONIGHT. LOWER STRATUS WILL DEVELOP TONIGHT AS LOW- LEVEL MOISTURE INCREASES AHEAD OF SURGING DRYLINE. 1000-1500 FT AGL CIGS LOOK HIGHLY PROBABLE TONIGHT WITH A CHANCE FOR IFR. DID NOT FEEL CONFIDENT ENOUGH TO FORECAST IFR GIVEN THE STRONG SOUTHERLY WINDS HOLDING UP OVERNIGHT. JMC PREV DISCUSSION... /ISSUED 321 AM CST SAT FEB 9 2013/ DISCUSSION... A SHORTWAVE TROUGH OVER THE SOUTHWEST EARLY THIS MORNING IS PROGGED TO MOVE EAST/NORTHEAST INTO THE CENTRAL ROCKIES THIS EVENING. MEANWHILE...LOW PRESSURE WILL DEEPEN OVER THE HIGH PLAINS OF EASTERN COLORADO LEADING TO STRONG SOUTHERLY WINDS ACROSS MUCH OF THE SOUTHERN AND CENTRAL PLAINS STATES. A WIND ADVISORY WILL REMAIN IN EFFECT FOR MUCH OF CENTRAL AND WESTERN KANSAS WHILE WINDS MAY FLIRT WITH ADVISORY LEVEL CONDITIONS AS FAR EAST AS THE KANSAS TURNPIKE. WITH A FEW BREAKS IN THE CLOUDS...HIGHS MAY RISE INTO THE LOW 50S BUT CONFIDENCE IN THIS SCENARIO REMAINS LOW AND GENERALLY TRENDED SLIGHTLY LOWER WITH VALUES IN THE 48-53 DEGREE RANGE ANTICIPATED. TONIGHT...MOISTURE TRANSPORT/MUCAPE CONTINUE TO BE MAXIMIZED ACROSS THE AREA TONIGHT WITHIN DIFFLUENT MID/UPPER FLOW EAST OF A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED H5 TROUGH AS IT EMERGES OUT OF THE ROCKIES AND OVER THE CENTRAL PLAINS. GENERALLY FOLLOWED THE PREVIOUS FORECAST AND TRIED TO PROVIDE MORE TIMING BRINGING AN END TO PRECIPITATION ACROSS MUCH OF THE AREA AFTER 09Z AS A DRY SLOT WRAPS INTO THE DEVELOPING MID-LATITUDE CYCLONE. WITH MUCAPE 300-600 J/KG WE ARE STILL EXPECTING SOME EMBEDDED THUNDERSTORMS BUT STRONG STORMS SHOULD REMAIN LIMITED. SUNDAY...ANOTHER WINDY DAY APPEARS LIKELY IN THE WAKE OF THE DRYLINE/PAC FRONT AND A WIND ADVISORY WILL LIKELY BE ISSUED FOR MUCH OF THE AREA. THE WESTERLY WINDS WILL ADVECT DRIER AIR ACROSS THE AREA HELPING TEMPERATURES TO CLIMB TO ABOVE NORMAL READINGS WITH HIGHS IN THE 50S AND 60S ACROSS MUCH OF THE AREA. PORTIONS OF CENTRAL KANSAS MAY STILL BE IMPACTED BY CLOUDS BUT THE PRECIPITATION SHIELD IS EXPECTED TO REMAIN NORTH OF THE AREA AT THIS TIME. CLOUD COVER MAY IMPACT HIGHS ALONG THE I-70 CORRIDOR ON SUNDAY WHERE TEMPERATURES MAY STRUGGLE TO CLIMB OUT OF THE 40S. MONDAY-FRIDAY...TEMPERATURES BEHIND THE COLD FRONT WILL RETURN TO MORE SEASONABLE VALUES EARLY IN THE WEEK WITH HIGHS MAINLY IN THE 40S. ANOTHER SHORTWAVE TROUGH IS EXPECTED TO IMPACT PORTIONS OF THE SOUTHERN PLAINS BUT PRECIPITATION ASSOCIATED WITH THIS SYSTEM IS EXPECTED TO REMAIN MOSTLY SOUTH OF THE OKLAHOMA STATE LINE. THERE IS STILL SOME UNCERTAINTY IN THE TRACK OF THIS SYSTEM AND MAINTAINED LOW POPS FOR A STRAY SHOWER NEAR THE OK STATE LINE ON TUESDAY. SHORTWAVE MID/UPPER RIDGING WILL RETURN TO THE CENTRAL PLAINS ON WED WITH RISING HEIGHTS/INCREASING THICKNESS SUPPORTING RISING TEMPERATURES ACROSS THE AREA. MORE UNCERTAINTY ARRIVES LATER IN THE WEEK AS ANOTHER TROUGH IS PROGGED TO BUILD SOUTH ACROSS THE CENTRAL CONUS WITH A SERIES OF SHORTWAVE TROUGHS HELPING TO DRIVE A COLDER CANADIAN AIRMASS SOUTH ACROSS THE AREA. MAINTAINED LOW PROBABILITIES FOR SOME LIGHT PRECIPITATION BUT UNCERTAINTY REMAINS HIGH AT THIS TIME. MCGUIRE && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 49 45 54 28 / 50 70 10 0 HUTCHINSON 50 42 51 27 / 50 70 0 0 NEWTON 48 44 51 28 / 50 70 10 0 ELDORADO 48 46 54 28 / 40 70 10 0 WINFIELD-KWLD 49 46 58 28 / 50 70 10 0 RUSSELL 53 35 48 24 / 50 70 10 0 GREAT BEND 53 37 48 24 / 50 70 10 0 SALINA 52 43 50 28 / 50 70 10 0 MCPHERSON 50 43 50 28 / 50 70 10 0 COFFEYVILLE 49 48 64 33 / 40 80 20 0 CHANUTE 49 48 60 32 / 40 80 20 0 IOLA 49 48 59 32 / 30 80 20 0 PARSONS-KPPF 49 48 63 31 / 40 80 20 0 && .ICT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CST THIS EVENING FOR KSZ032-033-047-048- 050. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1134 AM CST SAT FEB 9 2013 ...UPDATE TO AVIATION... .DISCUSSION... UPPER LOW WAS OVER THE GREAT BASIN FRIDAY EVENING WITH BROAD CIRRUS PLUME NORTHEAST INTO THE CENTRAL PLAINS. PRECIPITABLE WATER VALUES WERE WELL BELOW NORMAL FROM KANSAS SOUTHEAST INTO EAST TEXAS...BUT HIGHER VALUES WERE OVER WEST AND SOUTHWEST TEXAS. PRESSURE GRADIENT OVER THE CENTRAL AND SOUTHERN PLAINS WAS TIGHTENING WITH STEADY OVERNIGHT PRESSURE FALLS IN THE WEST. MAIN FORECAST CHALLENGES ARE PRECIPITATION CHANCES AND WIND SPEEDS THROUGH SUNDAY AFTERNOON. WINDS SLOWLY CRANK UP TODAY AS SURFACE HIGH PRESSURE SETTLES IN BEHIND THE NORTHEAST CONUS BLIZZARD AND THE UPSTREAM LOW CROSSES THE CROSSES THE ROCKIES. BEST DAYTIME PRESSURE FALLS TO BE TO THE NORTHWEST AND KEEP A SLIGHTLY BACKED ANGLE TO THE WINDS. WITH CLOUDS HELPING TO HINDER BEST MIXING...WILL KEEP ADVISORY SPEEDS OUT OF THE FORECAST...BUT WESTERN LOCATIONS LOOK TO BE CLOSE BY MID AFTERNOON AND WILL BE THE PRIME AREA TO BE MONITORED. DEEP MID LEVEL SOUTHWEST FLOW BRINGS AN INITIAL BAND OF HIGH PW VALUES /AROUND TWO STANDARD DEVIATIONS ABOVE NORMAL FOR TOPEKA/ NORTHEAST INTO EASTERN KANSAS THIS AFTERNOON. FORCING VIA ISENTROPIC LIFT IS NOT STRONG...BUT MAY BE ENOUGH TO PRODUCE SCATTERED SHOWERS AND PERHAPS A FEW THUNDERSTORMS. OF NOTE...SOME GUIDANCE HAS THE AFTERNOON PERIOD AS THE WETTEST OF THE COMING 36 HOURS...AND RECENT RUNS OF THE RAP AS WELL AS THE 06Z NAM DEVELOP THIS BAND AS WELL. THIS POSSIBLE INITIAL BAND SHOULD DIMINISH AS IT MOVES NORTHEAST THIS EVENING...WITH THE NEXT BAND MOST LIKELY TO AFFECT THE AREA IN THE 03Z-09Z RANGE AS THE BEST Q-VECTOR CONVERGENCE MEETS WITH THE MORE IMPRESSIVE PW TONGUE. THIS WOULD ALSO BE WHEN THE GREATEST ELEVATED CAPE WOULD MOVE THROUGH...STILL IN THE 200-300 J/KG RANGE...BUT ALSO WHEN THE CLOUD-BEARING SHEAR IS AT A RELATIVE MINIMUM. GETTING SEVERE LEVELS OF HAIL OR WIND WOULD SEEM TO BE A STRUGGLE THOUGH WITH 50KTS OF WINDS LESS THAN 2000 FEET AGL AT LEAST SOME CONSIDERABLE GUSTS COULD OCCUR. DRY SLOT TO MOVE IN BY DAWN SUNDAY WITH PRECIPITATION RAPIDLY MOVING NORTHEAST ON VERY STOUT MID LEVEL WINDS. SURFACE WINDS SHOULD STAY ON THE BREEZY SIDE THROUGH MUCH OF THE NIGHT..WITH VEERING AND INCREASING WINDS SUNDAY AS SUBSIDENCE AND LOW LEVEL LAPSE RATES PICK UP WITH THE SYSTEM HEADING NORTHEAST. ADVISORY LEVEL SPEEDS APPEAR A PRETTY DECENT BET FOR AT LEAST NORTHERN AREAS FOR MUCH OF THE DAY...THOUGH THERE ARE SOME INDICATIONS OF SOME LOW TO MID CLOUD WORKING THEIR WAY BACK SOUTHEAST INTO THE AREA. PICKING SPECIFIC TIMES AND LOCATIONS FOR AN ADVISORY AT THIS RANGE IS DIFFICULT AT BEST AND PLENTY OF TIME EXISTS FOR A HEADLINE TO BE ISSUED. WITH WINDS AND DRY AIR WILL ALSO BRING ELEVATED FIRE DANGER TO AT LEAST SOUTHERN AREAS WHERE COLD AIR ADVECTION WILL HOLD OFF THE LONGEST. THE EARLY TO MID WEEK PERIODS STILL ON THE BENIGN SIDE WITH THE SECONDARY UPPER TROF SWINGING THROUGH OKLAHOMA. NORTHWEST FLOW TO BRING AT LEAST ONE WAVE IN FOR THE THURSDAY-FRIDAY PERIODS THOUGH PRECIP CHANCES LOOK MEAGER IN LIMITED MOISTURE. TEMPS WILL BACK DOWN FROM SOMEWHAT ABOVE NORMAL LEVELS OF THE NEXT SEVERAL DAYS HOWEVER. 65 && .AVIATION... PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN ACROSS THE AREA CAUSING THE WINDS TO INCREASE THIS AFTERNOON OUT OF THE SOUTHEAST AROUND 17 KTS WITH GUSTS UP TO 25 KTS. MOISTURE WILL ALSO INCREASE FROM THE SOUTH AS THE MAIN SYSTEM PASS NORTH OF THE AREA. EXPECT SHOWERS TO DEVELOP THIS EVENING AROUND 06Z AND CONTINUE UNTIL 12Z. CAN NOT RULE OUT ISOLATED TSRA OVERNIGHT AS WELL. THERE MAY BE BRIEF PERIODS OF MVFR CIGS DURING THE SHOWER ACTIVITY BUT WILL BECOME VFR AROUND 12Z. THE WINDS WILL INCREASE TOMORROW MORNING OUT OF THE SOUTHWEST AS THE DRY SLOT MOVES THROUGH THE AREA. SANDERS && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
531 AM CST SAT FEB 9 2013 ...UPDATE TO AVIATION... .DISCUSSION... UPPER LOW WAS OVER THE GREAT BASIN FRIDAY EVENING WITH BROAD CIRRUS PLUME NORTHEAST INTO THE CENTRAL PLAINS. PRECIPITABLE WATER VALUES WERE WELL BELOW NORMAL FROM KANSAS SOUTHEAST INTO EAST TEXAS...BUT HIGHER VALUES WERE OVER WEST AND SOUTHWEST TEXAS. PRESSURE GRADIENT OVER THE CENTRAL AND SOUTHERN PLAINS WAS TIGHTENING WITH STEADY OVERNIGHT PRESSURE FALLS IN THE WEST. MAIN FORECAST CHALLENGES ARE PRECIPITATION CHANCES AND WIND SPEEDS THROUGH SUNDAY AFTERNOON. WINDS SLOWLY CRANK UP TODAY AS SURFACE HIGH PRESSURE SETTLES IN BEHIND THE NORTHEAST CONUS BLIZZARD AND THE UPSTREAM LOW CROSSES THE CROSSES THE ROCKIES. BEST DAYTIME PRESSURE FALLS TO BE TO THE NORTHWEST AND KEEP A SLIGHTLY BACKED ANGLE TO THE WINDS. WITH CLOUDS HELPING TO HINDER BEST MIXING...WILL KEEP ADVISORY SPEEDS OUT OF THE FORECAST...BUT WESTERN LOCATIONS LOOK TO BE CLOSE BY MID AFTERNOON AND WILL BE THE PRIME AREA TO BE MONITORED. DEEP MID LEVEL SOUTHWEST FLOW BRINGS AN INITIAL BAND OF HIGH PW VALUES /AROUND TWO STANDARD DEVIATIONS ABOVE NORMAL FOR TOPEKA/ NORTHEAST INTO EASTERN KANSAS THIS AFTERNOON. FORCING VIA ISENTROPIC LIFT IS NOT STRONG...BUT MAY BE ENOUGH TO PRODUCE SCATTERED SHOWERS AND PERHAPS A FEW THUNDERSTORMS. OF NOTE...SOME GUIDANCE HAS THE AFTERNOON PERIOD AS THE WETTEST OF THE COMING 36 HOURS...AND RECENT RUNS OF THE RAP AS WELL AS THE 06Z NAM DEVELOP THIS BAND AS WELL. THIS POSSIBLE INITIAL BAND SHOULD DIMINISH AS IT MOVES NORTHEAST THIS EVENING...WITH THE NEXT BAND MOST LIKELY TO AFFECT THE AREA IN THE 03Z-09Z RANGE AS THE BEST Q-VECTOR CONVERGENCE MEETS WITH THE MORE IMPRESSIVE PW TONGUE. THIS WOULD ALSO BE WHEN THE GREATEST ELEVATED CAPE WOULD MOVE THROUGH...STILL IN THE 200-300 J/KG RANGE...BUT ALSO WHEN THE CLOUD-BEARING SHEAR IS AT A RELATIVE MINIMUM. GETTING SEVERE LEVELS OF HAIL OR WIND WOULD SEEM TO BE A STRUGGLE THOUGH WITH 50KTS OF WINDS LESS THAN 2000 FEET AGL AT LEAST SOME CONSIDERABLE GUSTS COULD OCCUR. DRY SLOT TO MOVE IN BY DAWN SUNDAY WITH PRECIPITATION RAPIDLY MOVING NORTHEAST ON VERY STOUT MID LEVEL WINDS. SURFACE WINDS SHOULD STAY ON THE BREEZY SIDE THROUGH MUCH OF THE NIGHT..WITH VEERING AND INCREASING WINDS SUNDAY AS SUBSIDENCE AND LOW LEVEL LAPSE RATES PICK UP WITH THE SYSTEM HEADING NORTHEAST. ADVISORY LEVEL SPEEDS APPEAR A PRETTY DECENT BET FOR AT LEAST NORTHERN AREAS FOR MUCH OF THE DAY...THOUGH THERE ARE SOME INDICATIONS OF SOME LOW TO MID CLOUD WORKING THEIR WAY BACK SOUTHEAST INTO THE AREA. PICKING SPECIFIC TIMES AND LOCATIONS FOR AN ADVISORY AT THIS RANGE IS DIFFICULT AT BEST AND PLENTY OF TIME EXISTS FOR A HEADLINE TO BE ISSUED. WITH WINDS AND DRY AIR WILL ALSO BRING ELEVATED FIRE DANGER TO AT LEAST SOUTHERN AREAS WHERE COLD AIR ADVECTION WILL HOLD OFF THE LONGEST. THE EARLY TO MID WEEK PERIODS STILL ON THE BENIGN SIDE WITH THE SECONDARY UPPER TROF SWINGING THROUGH OKLAHOMA. NORTHWEST FLOW TO BRING AT LEAST ONE WAVE IN FOR THE THURSDAY-FRIDAY PERIODS THOUGH PRECIP CHANCES LOOK MEAGER IN LIMITED MOISTURE. TEMPS WILL BACK DOWN FROM SOMEWHAT ABOVE NORMAL LEVELS OF THE NEXT SEVERAL DAYS HOWEVER. 65 && .AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THE PERIOD. A TIGHTENING PRESSURE GRADIENT WILL MAKE FOR WINDS FROM THE SOUTHEAST NEAR 17 KTS WITH GUSTS UP TO 25 KTS AFTER 14Z TODAY. MOISTURE WILL BEGIN TO INCREASE LATER TODAY AND EXPECT SOME SHOWERS TO DEVELOP LATER THIS EVENING AND CONTINUE ON AND OFF OVERNIGHT. SOME ISOLATED TSRA IS POSSIBLE AS WELL. AREAS OF MVFR CIGS ARE EXPECTED TO DEVELOP AFTER 09Z SUNDAY. 53 && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
338 AM CST SAT FEB 9 2013 .DISCUSSION... UPPER LOW WAS OVER THE GREAT BASIN FRIDAY EVENING WITH BROAD CIRRUS PLUME NORTHEAST INTO THE CENTRAL PLAINS. PRECIPITABLE WATER VALUES WERE WELL BELOW NORMAL FROM KANSAS SOUTHEAST INTO EAST TEXAS...BUT HIGHER VALUES WERE OVER WEST AND SOUTHWEST TEXAS. PRESSURE GRADIENT OVER THE CENTRAL AND SOUTHERN PLAINS WAS TIGHTENING WITH STEADY OVERNIGHT PRESSURE FALLS IN THE WEST. MAIN FORECAST CHALLENGES ARE PRECIPITATION CHANCES AND WIND SPEEDS THROUGH SUNDAY AFTERNOON. WINDS SLOWLY CRANK UP TODAY AS SURFACE HIGH PRESSURE SETTLES IN BEHIND THE NORTHEAST CONUS BLIZZARD AND THE UPSTREAM LOW CROSSES THE CROSSES THE ROCKIES. BEST DAYTIME PRESSURE FALLS TO BE TO THE NORTHWEST AND KEEP A SLIGHTLY BACKED ANGLE TO THE WINDS. WITH CLOUDS HELPING TO HINDER BEST MIXING...WILL KEEP ADVISORY SPEEDS OUT OF THE FORECAST...BUT WESTERN LOCATIONS LOOK TO BE CLOSE BY MID AFTERNOON AND WILL BE THE PRIME AREA TO BE MONITORED. DEEP MID LEVEL SOUTHWEST FLOW BRINGS AN INITIAL BAND OF HIGH PW VALUES /AROUND TWO STANDARD DEVIATIONS ABOVE NORMAL FOR TOPEKA/ NORTHEAST INTO EASTERN KANSAS THIS AFTERNOON. FORCING VIA ISENTROPIC LIFT IS NOT STRONG...BUT MAY BE ENOUGH TO PRODUCE SCATTERED SHOWERS AND PERHAPS A FEW THUNDERSTORMS. OF NOTE...SOME GUIDANCE HAS THE AFTERNOON PERIOD AS THE WETTEST OF THE COMING 36 HOURS...AND RECENT RUNS OF THE RAP AS WELL AS THE 06Z NAM DEVELOP THIS BAND AS WELL. THIS POSSIBLE INITIAL BAND SHOULD DIMINISH AS IT MOVES NORTHEAST THIS EVENING...WITH THE NEXT BAND MOST LIKELY TO AFFECT THE AREA IN THE 03Z-09Z RANGE AS THE BEST Q-VECTOR CONVERGENCE MEETS WITH THE MORE IMPRESSIVE PW TONGUE. THIS WOULD ALSO BE WHEN THE GREATEST ELEVATED CAPE WOULD MOVE THROUGH...STILL IN THE 200-300 J/KG RANGE...BUT ALSO WHEN THE CLOUD-BEARING SHEAR IS AT A RELATIVE MINIMUM. GETTING SEVERE LEVELS OF HAIL OR WIND WOULD SEEM TO BE A STRUGGLE THOUGH WITH 50KTS OF WINDS LESS THAN 2000 FEET AGL AT LEAST SOME CONSIDERABLE GUSTS COULD OCCUR. DRY SLOT TO MOVE IN BY DAWN SUNDAY WITH PRECIPITATION RAPIDLY MOVING NORTHEAST ON VERY STOUT MID LEVEL WINDS. SURFACE WINDS SHOULD STAY ON THE BREEZY SIDE THROUGH MUCH OF THE NIGHT..WITH VEERING AND INCREASING WINDS SUNDAY AS SUBSIDENCE AND LOW LEVEL LAPSE RATES PICK UP WITH THE SYSTEM HEADING NORTHEAST. ADVISORY LEVEL SPEEDS APPEAR A PRETTY DECENT BET FOR AT LEAST NORTHERN AREAS FOR MUCH OF THE DAY...THOUGH THERE ARE SOME INDICATIONS OF SOME LOW TO MID CLOUD WORKING THEIR WAY BACK SOUTHEAST INTO THE AREA. PICKING SPECIFIC TIMES AND LOCATIONS FOR AN ADVISORY AT THIS RANGE IS DIFFICULT AT BEST AND PLENTY OF TIME EXISTS FOR A HEADLINE TO BE ISSUED. WITH WINDS AND DRY AIR WILL ALSO BRING ELEVATED FIRE DANGER TO AT LEAST SOUTHERN AREAS WHERE COLD AIR ADVECTION WILL HOLD OFF THE LONGEST. THE EARLY TO MID WEEK PERIODS STILL ON THE BENIGN SIDE WITH THE SECONDARY UPPER TROF SWINGING THROUGH OKLAHOMA. NORTHWEST FLOW TO BRING AT LEAST ONE WAVE IN FOR THE THURSDAY-FRIDAY PERIODS THOUGH PRECIP CHANCES LOOK MEAGER IN LIMITED MOISTURE. TEMPS WILL BACK DOWN FROM SOMEWHAT ABOVE NORMAL LEVELS OF THE NEXT SEVERAL DAYS HOWEVER. 65 && .AVIATION... MOISTURE RETURN AHEAD OF THE NEXT STORM SYSTEM STILL APPEARS WILL REMAIN LIMITED WITH MAINLY MID AND HIGH CLOUDS AOA 10KFT UNTIL AFT 23Z/09 WHEN A VFR STRATOCU DECK AT 4-5KFT DEVELOPS. CONFIDENCE IN ANY CONVECTION THROUGH 06Z/10 REMAINS TOO LOW TO INSERT INTO TAF SITES AT THIS POINT. SOUTHEAST WINDS AROUND 10KTS WILL BECOME MORE SOUTHERLY AND INCREASE TO 15-20KTS AFT 14Z WITH GUSTS NEAR 25 KTS THROUGH 06Z/10. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
916 PM EST SUN FEB 10 2013 .Forecast Update... Issued at 910 PM EST Sun Feb 10 2013 Not seeing much to increase forecast confidence as the evening wears on. Precip development has been limited at best, but the mesoscale models continue to generate chance POPs later this evening. Might otherwise be inclined to drastically lower POPs with this evening update, but the RUC and HRRR both seem to have a handle on what is out there now, and start to show development near the I-65 corridor around 03-04Z. Already updated to clean up evening wording and remove thunder, and lowered POPs to chance at that time. Otherwise the forecast has been left as-is and most tweaks for the rest of the evening will be grid details. && .Short Term (Tonight - Monday Night)... Issued at 300 PM EST Sun Feb 10 2013 A vertically stacked low continues to churn across the Central Plains this afternoon. Out ahead of this low, a ridge has amplified over the Ohio Valley, allowing a warm and rather moist airmass to push north into the Ohio Valley. Showers and embedded thunderstorms have pushed into the western half of the CWA this afternoon. A notable weakening trend has occurred with this activity over the past few hours as it has pushed east, due to it outrunning the better elevated instability and the strongest forcing pushing north. This weakening trend will continue through the remainder of the afternoon, but much of the area still has a chance of seeing an isolated thunderstorm as the main line pushes east. Winds out ahead of this line have been breezy, especially across areas that received a break in the clouds early this afternoon. Simpson County for example, gusted to 37 knots as they broke out in some sunshine. However, winds should continue to slowly slacken as this system rolls through and saturates the column, limiting any mixing. Some of the stronger convection has mixed down some higher momentum air this afternoon, but the potential for any damaging gusts appears very low as a stout cap remains in place. After the main line rolls through late this afternoon into the early evening, attention will then turn to the southwest as another weak shortwave ejects out of the southwest flow aloft. Most high-res models are indicating some low-topped convective showers developing along the surface front as this wave rides up along it tonight. Therefore, will increase pops once again this evening into tonight to account for these showers. The surface front will clear the area and dry air will work into the region by Monday morning. The only issue on Monday will be the gusty wind potential, especially across southern Indiana and the northern Bluegrass. Currently have winds gusting to around 35 MPH during the afternoon hours, as mostly sunny skies and cold air advection aloft helps aid in mixing. These gusts are just below advisory criteria and the potential for an advisory across the northern CWA will need to be revisited in coming forecasts. With the expected deep mixing and a good amount of sunshine, have gone a bit above guidance for highs on Monday (upper 40s to middle 50s). Winds will begin to die down Monday night as a surface ridge pushes into the region. Lows Monday night will drop into the upper 20s and lower 30s, with mostly clear skies. .Long Term (Tuesday - Sunday)... Issued at 255 PM EST Sun Feb 10 2013 The first concern in the long term is, of course, the Tuesday night/Wednesday system. Looking at the models, the EC has had slightly better run-to-run consistency than the GFS, especially on Wednesday, with the path of the surface low that will be going by to our south Tuesday night/Wednesday. The EC also has been leading the way with verification of surface temperatures and dew points lately. Still, the EC isn`t perfect and it looks like the model is probably ejecting the low eastward too quickly. We will also need to dial in a bit of a northward correction to account for the possibility that the models might be taking this southern stream system a bit too far south. So, given all that, will go with a surface low path from Louisiana Tuesday evening to between Birmingham and Atlanta Wednesday morning to the VA/NC coast Wednesday evening. The upper trof associated with this system is a narrow appendage poking southwestward from the main upper trof well to our north. As a result it is quite far away from the polar vortex over the Canadian Archipelago and so there isn`t much cold air for this system to work with. So, despite the favorable track of the low to give us a snowstorm, it looks like we son`t have the requisite cold air and we should actually see rain in the south and a mix in the north. Of course, for a snowstorm one also needs a rich source of moisture. The GFS`s QPF is getting no real support from the EC, GEM, HPC, or GEFS and there is quite a bit of spread among the perturbation plumes in the GEFS (and SREF for that matter). So, won`t latch on to the GFS`s robust QPF numbers at this time and instead will go with more conservative amounts. Also supporting lower QPF values is a layer of surface-700hPa dry air that will have to be overcome Tuesday night before precipitation reaches the surface. In addition, the GFS tends to count virga as QPF. In the grids we have gone with 24-hour totals Tuesday night-Wednesday ranging from around a tenth of an inch in the north to a quarter of an inch far south. Even in the north where some snow will be possible, only a portion of that QPF will be snow. Ground temperatures will be warm from temperatures in the 45-50 degree range Tuesday afternoon, and highs Wednesday afternoon should get up to around 40. So, other than maybe a few tricky hours around the Wednesday morning commute, overall this system shouldn`t be too bad. Of course, we`ll need to keep an eye on it and the forecasts will surely evolve as we get closer to Tuesday night. A large upper trof will then dig into the Plains late in the week and invade the eastern half of the country over the weekend. This trof will have a direct connection to the main upper low over the Canadian Arctic and so will bring in colder air. Most of the precipitation associated with this trof will remain to our north in areas of better relative humidity and upper support. The best chance for precipitation for us will likely be with shortwave trofs diving down the backside of the trof. Those types of small-scale features are very difficult to accurately forecast so far out in the future, so will keep PoPs low at this time. Our warmest day should be Thursday with highs around 50. Once the late week upper trof comes in it will drop daily highs down into the 30s for the weekend. By Sunday morning we`ll probably dip into the teens, which is about ten degrees below normal for mid February. && .Aviation (00Z TAF Issuance)... Issued at 615 PM EST Sun Feb 10 2013 As the rain shield now over the Bluegrass prepares to exit LEX, fuel-alternate MVFR ceilings will take hold over all 3 central Kentucky TAF sites. Forecast confidence wanes quickly later in the evening, as it is still unclear how much if any precip will develop along the surface cold front, and how it will actually impact ceilings and vis. So far all the precip over central Illinois has been literally under the radar, with mainly IFR drizzle. However, with enough of an upper impulse to develop rain rather than drizzle, we could actually see improved visibilities. All that said, will go for a period of borderline IFR/MVFR conditions beginning mid to late evening, and lasting beyond midnight. Gusty south winds will continue until the front clears the area between 06-09Z Monday. Once the front goes through conditions will improve to VFR, with mainly scattered Cu or Sc at the top of a relatively deep mixing layer. West winds will be quite gusty, peaking over 20 kt at BWG and pushing 30 kt at SDF and LEX. The combination of the magnitude and the nearly due west direction will be problematic for runway selection at SDF. Gusts should settle down around sunset Monday evening, too late to be worthy of another line in BWG and LEX, but still holding a solid 10-12 kt through the planning period in SDF. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........RAS Short Term.......KD Long Term........13 Aviation.........RAS
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
920 PM CST SUN FEB 10 2013 .DISCUSSION... SURFACE ANALYSIS THIS EVENING INDICATED THAT OUR FRONTAL BOUNDARY WAS STALLED NEAR A MEM...MLU...LCH LINE. MUCH DRIER AIR IN THE LOWER LEVELS OF THE ATMOSPHERE HAS INFILTRATED THE REGION FROM THE WEST BUT STILL DEALING WITH A FAIRLY MOIST PROFILE ACROSS OUR EXTREME EASTERN ZONES. ALSO BEGINNING TO SEE SOME REDEVELOPMENT OF WIDELY SCATTERED SHOWERS ACROSS OUR EXTREME EASTERN ZONES AS WELL. FOR THIS REASON...HAVE LEFT POPS PRETTY MUCH UNCHANGED THROUGH THE NIGHT ADVERTISING CHANCE POPS TO OUR SOUTH AND EAST. A QUICK LOOK AT THE 00Z NAM AS WELL AS THE LATEST RAP SHOWS THAT SCATTERED SHOWERS WILL BE POSSIBLE ALL NIGHT...MAINLY ACROSS OUR SOUTHEAST ZONES. THESE MODELS ALSO SUGGEST THAT THE FRONTAL BOUNDARY WILL FINALLY GET SHOVED SOUTH AND EAST OVERNIGHT WHICH WILL ALLOW FOR SOME DRIER AIR TO PUSH THROUGH AT LEAST OUT EASTERN MOST ZONES. HOWEVER...MID AND HIGH LEVEL CLOUDS SHOULD HANG ON FOR THE REMAINDER OF THE NIGHT ACROSS ALL BUT OUR EXTREME NW ZONES. DESPITE THE DRIER AIR...FEEL LIKE THE CLOUD COVER SHOULD HOLD TEMPS UP SOMEWHAT OVERNIGHT. MOS GUIDANCE WAS RUNNING A LITTLE TOO COOL WITH ITS 03Z TEMPS ACROSS A FEW SELECTED CITIES THIS EVENING SO HAVE BUMPED UP OVERNIGHT MINS JUST A DEGREE OR TWO ACROSS A FEW LOCATIONS. DID MAKE SOME ADJUSTMENTS TO DEWPOINTS GIVEN THE SLOWER INFILTRATION OF DRIER AIR INTO OUR EASTERN ZONES THIS EVENING AND SOME COSMETIC CHANGES TO SKY GRIDS. OTHERWISE...NO OTHER CHANGES WERE NECESSARY THIS EVENING. UPDATE OUT SHORTLY...13. && .AVIATION... MOSTLY VFR FLIGHT WEATHER TONIGHT AND MONDAY. HOWEVER...AREAS SOUTH AND EAST OF A KMLU TO KLFK LINE WILL EXPERIENCE LOW VFR CIGS... BETWEEN 4 AND 6 KFT...WITH ISOLATED SHOWERS AND TSTMS. EXPECT SOME BRIEF VISIBILITY RESTRICTIONS TO NEAR IFR IN THE STRONGER CONVECTION. THIS AREA OF LOW VFR CIGS AND CONVECTION WILL GRADUALLY SPREAD TO THE NORTH ON MONDAY...TO NEAR A KELD TO KTYR LINE BY 12/00Z. SURFACE WIND LIGHT AND VARIABLE TONIGHT...AND NORTHEAST 5 TO 10 KTS MONDAY. /14/ && .PRELIMINARY POINT TEMPS/POPS... SHV 49 61 46 57 40 / 20 20 50 60 20 MLU 51 59 46 55 41 / 40 40 50 60 40 DEQ 35 61 38 49 34 / 10 10 30 60 40 TXK 42 63 44 51 36 / 10 10 40 60 30 ELD 44 61 43 54 37 / 20 20 40 60 40 TYR 48 61 46 55 37 / 10 20 60 60 20 GGG 49 62 46 55 38 / 20 20 60 60 20 LFK 52 63 50 60 41 / 30 40 60 60 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 13/14
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
635 AM EST SAT FEB 9 2013 .SYNOPSIS... COLD NORTHWESTERLY WINDS WILL BRING SCATTERED SNOW SHOWERS AND FLURRIES TO PORTIONS OF THE AREA THIS MORNING. HIGH PRESSURE WILL THEN BUILD IN FOR A DRY WEEKEND BEFORE A COLD FRONT CROSSES THE AREA ON MONDAY. && .NEAR TERM /THROUGH TONIGHT/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SHIFTING EAST OF THE AREA AND MERGING WITH A COASTAL LOW OVER NEW ENGLAND. AT THE SURFACE...A BROAD AREA OF HIGH PRESSURE EXTENDS ACROSS THE GREAT LAKES AND OHIO VALLEY WITH A 976MB NOR`EASTER OFF THE NEW ENGLAND COAST. BETWEEN THE TWO FEATURES...THE UPPER OHIO VALLEY IS IN A NORTH-NORTHWESTERLY FLOW WITH A TIGHTENED PRESSURE GRADIENT. WITH LAKE ERIE PARTIALLY FROZEN...A LAKE EFFECT FETCH FROM HURON IS ALLOWING FOR LINGERING FLURRIES FOR THE LOWLANDS AND UPLOPING SNOW SHOWERS FOR THE RIDGES THIS MORNING. TODAY AND TONIGHT...MODELS ARE IN AGREEMENT THAT A BROAD 500MB RIDGE ALONG WITH SURFACE HIGH WILL SLIDE ACROSS THE OHIO VALLEY. THIS WILL ALLOW FOR DRIER LOW-LEVEL AIR TO ADVECT INTO THE AREA...BRINGING AN END TO FLURRIES AROUND DAWN AND UPSLOPING BY AROUND 15Z TODAY. WAA AND SUBSIDENCE ALOFT WILL ALLOW FOR CLOUDS TO BEGIN TO DECREASE IN COVERAGE THIS AFTERNOON WITH SKIES CLEARING BY TONIGHT. FOR TEMPS...HIGHS TODAY ARE FAIRLY CLOSE TO LAMP GUIDANCE AND RANGE FROM THE MID 20S NORTH OF THE I-80 CORRIDOR AND ACROSS THE LAUREL HIGHLANDS/ALLEGHENY FRONT TO THE MID 30S ACROSS PORTIONS OF EASTERN OHIO AND NORTHERN WV. CLEAR SKIES WITH A HIGH CENTERED EAST OF THE AREA TONIGHT WILL ALLOW FOR RADIATIONAL COOLING...ESPECIALLY EAST OF PITTSBURGH. THUS...LOWS TONIGHT RANGE FROM THE SINGLE DIGITS IN FOREST/JEFFERSON/VENANGO COUNTIES TO NEAR 20 IN PORTIONS OF EASTERN OHIO. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... GFS/NAM/ECMWF REMAIN IN AGREEMENT THAT A BROAD TROUGH WILL CROSS THE UPPER OHIO VALLEY ON SUNDAY. WITH THE SURFACE HIGH PUSHING EAST OF THE AREA...AN ENHANCED SOUTHERLY FLOW BENEATH THE RIDGING WILL PROMOTE WAA ACROSS THE AREA. THIS WILL ALLOW FOR A WARM AND DRY DAY AS A SURFACE LOW MOVES INTO THE UPPER MIDWEST AND BEGINS TO BRING A COLD FRONT ACROSS THE OHIO VALLEY. CLOUDS WILL BE ON THE INCREASE AHEAD OF THIS SYSTEM ON SUNDAY. STILL...HIGHS ON SUNDAY WILL 10 TO 15 DEGREES ABOVE NORMAL...RANGING FROM THE MID 40S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES TO THE MID 50S IN ERN OH AND N-CNTRL WV. SUNDAY NIGHT INTO MONDAY...GFS/ECMWF AGREE THAT THE COLD FRONT WILL PUSH PRECIP INTO THE AREA AFTER 00Z MON...BRINGING CATEGORICAL POPS ACROSS THE AREA BY DAWN ON MONDAY. WAA AHEAD OF THE FRONT WILL BRING 850MB TEMPS UP TO 4-6C ACROSS THE AREA AND ALLOW FOR A SUFFICIENT MELTING LAYER WITH ALL PRECIP REACHING THE SURFACE IN THE FORM OF LIQUID EARLY MONDAY. LOWS SUNDAY NIGHT WILL RANGE FROM NEAR FREEZING ACROSS THE EASTERN RIDGES AND FOREST COUNTY TO THE LOWER 40S SOUTH AND WEST OF PITTSBURGH. WITH THE WARM SURGE OF AIR AHEAD OF THE FRONT...HIGHS ON MONDAY ARE AGAIN AROUND 10 TO 15 DEGREES ABOVE NORMAL. GFS/NAM/SREF ALL STILL INDICATE THAT SFC TEMPS IN FOREST/JEFFERSON/CLARION AND GARRETT/TUCKER COUNTIES COULD SEE A BRIEF PERIOD OF FREEZING RAIN WHERE COLD AIR BECOMES TRAPPED AT THE SURFACE. GENERALLY THINK THIS WOULD BE A VERY BRIEF PERIOD OF FREEZING RAIN WITH SOUTHERLY WINDS QUICKLY ERODING A SUB-FREEZING SFC LAYER. THUS...ICE ACCUMULATIONS OF LESS THAN A TENTH OF AN INCH ARE FORECAST FOR THESE AREAS WHICH ARE ALSO HIGHLIGHTED IN THE HWO. CAA WILL BE RELATIVELY WEAK IN THE WAKE OF THE FRONT WITH WINDS SHIFTING TO SWRLY MON AFTERNOON. THUS...PRECIP IS FORECAST TO REMAIN ALL RAIN ON MONDAY. CRITICAL THICKNESSES DROP SOUTH OF THE AREA AFTER 00Z TUESDAY AND THUS HAVE A CHANGE OVER TO SNOW SHOWERS WITH LITTLE ACCUMULATION EXPECTED. && .LONG TERM /TUESDAY THROUGH FRIDAY/... GFS AND ECMWF BOTH DEPICT A WAVE EJECTING FROM SRN PLNS TUE NGT. THE FORMER MODEL AMPLIFIES THIS WAVE AS IT CROSSES THE SRN APLCNS WHILE THE LATTER IS MORE PROGRESSIVE. IF THE GFS IS CORRECT... A COASTAL LOW WILL DVLP AS THIS WAVE APRCHS THE COAST...AND PCPN WILL SPREAD NWD INTO AT LEAST SRN PORTIONS OF THE FCST AREA. IF THE ECMWF IS CORRECT...THE FCST AREA LKLY WILL RMN DRY. ATTM... HAVE KEPT POPS BLW MEX NUMBERS...BUT SLGTLY HIGHER THAN THEY WERE IN PREV FCST. ANY PCPN DURG THIS TIME WILL BE SNOW OWING TO PERSISTENT COLD AIR. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... LOW LEVEL INSTABILITY AND MOISTURE SHOULD ALLOW FOR SCATTERED SNOW SHOWERS TO CONTINUE WITH COLD ADVECTION INTO THE MORNING HOURS. LOW LEVEL SATURATION CAPS OUT AROUND 2-4 KFT ACROSS THE AREA...SO MVFR STRATUS SHOULD REMAIN THROUGH THE MORNING HOURS. HOWEVER...AFTER ROUGHLY 17Z...THE EROSION OF THE INVERSION AS WELL AS DRIER BOUNDARY LAYER AIR SHOULD ALLOW EVERYONE TO SCATTER OUT AND EVENTUALLY CLEAR...YIELDING VFR CONDITIONS BY AFTERNOON. FRIES .OUTLOOK.../SATURDAY THROUGH WEDNESDAY/... WAA ALOFT AND EXITING EAST COAST SFC LOW WILL SHIFT THE MVFR CLOUD DECK EASTWARD SATURDAY MORNING. SKIES WILL SLOWLY CLEAR FROM WEST TO EAST DURING THE AFTERNOON. VFR CONDITIONS EXPECTED THROUGH SUNDAY. RESTRICTIONS RETURN SUNDAY NIGHT AND CONTINUE THROUGH MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001. OH...NONE. PA...NONE. WV...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
411 AM EST SAT FEB 9 2013 .SYNOPSIS... COLD NORTHWESTERLY WINDS WILL BRING SCATTERED SNOW SHOWERS AND FLURRIES TO PORTIONS OF THE AREA THIS MORNING. HIGH PRESSURE WILL THEN BUILD IN FOR A DRY WEEKEND BEFORE A COLD FRONT CROSSES THE AREA ON MONDAY. && .NEAR TERM /THROUGH TONIGHT/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SHIFTING EAST OF THE AREA AND MERGING WITH A COASTAL LOW OVER NEW ENGLAND. AT THE SURFACE...A BROAD AREA OF HIGH PRESSURE EXTENDS ACROSS THE GREAT LAKES AND OHIO VALLEY WITH A 976MB NOR`EASTER OFF THE NEW ENGLAND COAST. BETWEEN THE TWO FEATURES...THE UPPER OHIO VALLEY IS IN A NORTH-NORTHWESTERLY FLOW WITH A TIGHTENED PRESSURE GRADIENT. WITH LAKE ERIE PARTIALLY FROZEN...A LAKE EFFECT FETCH FROM HURON IS ALLOWING FOR LINGERING FLURRIES FOR THE LOWLANDS AND UPLOPING SNOW SHOWERS FOR THE RIDGES THIS MORNING. TODAY AND TONIGHT...MODELS ARE IN AGREEMENT THAT A BROAD 500MB RIDGE ALONG WITH SURFACE HIGH WILL SLIDE ACROSS THE OHIO VALLEY. THIS WILL ALLOW FOR DRIER LOW-LEVEL AIR TO ADVECT INTO THE AREA...BRINGING AN END TO FLURRIES AROUND DAWN AND UPSLOPING BY AROUND 15Z TODAY. WAA AND SUBSIDENCE ALOFT WILL ALLOW FOR CLOUDS TO BEGIN TO DECREASE IN COVERAGE THIS AFTERNOON WITH SKIES CLEARING BY TONIGHT. FOR TEMPS...HIGHS TODAY ARE FAIRLY CLOSE TO LAMP GUIDANCE AND RANGE FROM THE MID 20S NORTH OF THE I-80 CORRIDOR AND ACROSS THE LAUREL HIGHLANDS/ALLEGHENY FRONT TO THE MID 30S ACROSS PORTIONS OF EASTERN OHIO AND NORTHERN WV. CLEAR SKIES WITH A HIGH CENTERED EAST OF THE AREA TONIGHT WILL ALLOW FOR RADIATIONAL COOLING...ESPECIALLY EAST OF PITTSBURGH. THUS...LOWS TONIGHT RANGE FROM THE SINGLE DIGITS IN FOREST/JEFFERSON/VENANGO COUNTIES TO NEAR 20 IN PORTIONS OF EASTERN OHIO. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... GFS/NAM/ECMWF REMAIN IN AGREEMENT THAT A BROAD TROUGH WILL CROSS THE UPPER OHIO VALLEY ON SUNDAY. WITH THE SURFACE HIGH PUSHING EAST OF THE AREA...AN ENHANCED SOUTHERLY FLOW BENEATH THE RIDGING WILL PROMOTE WAA ACROSS THE AREA. THIS WILL ALLOW FOR A WARM AND DRY DAY AS A SURFACE LOW MOVES INTO THE UPPER MIDWEST AND BEGINS TO BRING A COLD FRONT ACROSS THE OHIO VALLEY. CLOUDS WILL BE ON THE INCREASE AHEAD OF THIS SYSTEM ON SUNDAY. STILL...HIGHS ON SUNDAY WILL 10 TO 15 DEGREES ABOVE NORMAL...RANGING FROM THE MID 40S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES TO THE MID 50S IN ERN OH AND N-CNTRL WV. SUNDAY NIGHT INTO MONDAY...GFS/ECMWF AGREE THAT THE COLD FRONT WILL PUSH PRECIP INTO THE AREA AFTER 00Z MON...BRINGING CATEGORICAL POPS ACROSS THE AREA BY DAWN ON MONDAY. WAA AHEAD OF THE FRONT WILL BRING 850MB TEMPS UP TO 4-6C ACROSS THE AREA AND ALLOW FOR A SUFFICIENT MELTING LAYER WITH ALL PRECIP REACHING THE SURFACE IN THE FORM OF LIQUID EARLY MONDAY. LOWS SUNDAY NIGHT WILL RANGE FROM NEAR FREEZING ACROSS THE EASTERN RIDGES AND FOREST COUNTY TO THE LOWER 40S SOUTH AND WEST OF PITTSBURGH. WITH THE WARM SURGE OF AIR AHEAD OF THE FRONT...HIGHS ON MONDAY ARE AGAIN AROUND 10 TO 15 DEGREES ABOVE NORMAL. GFS/NAM/SREF ALL STILL INDICATE THAT SFC TEMPS IN FOREST/JEFFERSON/CLARION AND GARRETT/TUCKER COUNTIES COULD SEE A BRIEF PERIOD OF FREEZING RAIN WHERE COLD AIR BECOMES TRAPPED AT THE SURFACE. GENERALLY THINK THIS WOULD BE A VERY BRIEF PERIOD OF FREEZING RAIN WITH SOUTHERLY WINDS QUICKLY ERODING A SUB-FREEZING SFC LAYER. THUS...ICE ACCUMULATIONS OF LESS THAN A TENTH OF AN INCH ARE FORECAST FOR THESE AREAS WHICH ARE ALSO HIGHLIGHTED IN THE HWO. CAA WILL BE RELATIVELY WEAK IN THE WAKE OF THE FRONT WITH WINDS SHIFTING TO SWRLY MON AFTERNOON. THUS...PRECIP IS FORECAST TO REMAIN ALL RAIN ON MONDAY. CRITICAL THICKNESSES DROP SOUTH OF THE AREA AFTER 00Z TUESDAY AND THUS HAVE A CHANGE OVER TO SNOW SHOWERS WITH LITTLE ACCUMULATION EXPECTED. && .LONG TERM /TUESDAY THROUGH FRIDAY/... GFS AND ECMWF BOTH DEPICT A WAVE EJECTING FROM SRN PLNS TUE NGT. THE FORMER MODEL AMPLIFIES THIS WAVE AS IT CROSSES THE SRN APLCNS WHILE THE LATTER IS MORE PROGRESSIVE. IF THE GFS IS CORRECT... A COASTAL LOW WILL DVLP AS THIS WAVE APRCHS THE COAST...AND PCPN WILL SPREAD NWD INTO AT LEAST SRN PORTIONS OF THE FCST AREA. IF THE ECMWF IS CORRECT...THE FCST AREA LKLY WILL RMN DRY. ATTM... HAVE KEPT POPS BLW MEX NUMBERS...BUT SLGTLY HIGHER THAN THEY WERE IN PREV FCST. ANY PCPN DURG THIS TIME WILL BE SNOW OWING TO PERSISTENT COLD AIR. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... LOW LEVEL INSTABILITY AND MOISTURE SHOULD ALLOW FOR SCATTERED SNOW SHOWERS TO CONTINUE WITH COLD ADVECTION INTO THE MORNING HOURS. LOW LEVEL SATURATION CAPS OUT AROUND 2 KFT ACROSS THE AREA...SO MVFR STRATUS SHOULD REMAIN THROUGH THE MORNING HOURS. HOWEVER...AFTER ROUGHLY 17Z...THE EROSION OF THE INVERSION AS WELL AS DRIER BOUNDARY LAYER AIR SHOULD ALLOW EVERYONE TO SCATTER OUT AND EVENTUALLY CLEAR...YIELDING VFR CONDITIONS BY AFTERNOON. FRIES .OUTLOOK.../SATURDAY THROUGH WEDNESDAY/... WAA ALOFT AND EXITING EAST COAST SFC LOW WILL SHIFT THE MVFR CLOUD DECK EASTWARD SATURDAY MORNING. SKIES WILL SLOWLY CLEAR FROM WEST TO EAST DURING THE AFTERNOON. VFR CONDITIONS EXPECTED THROUGH SUNDAY. RESTRICTIONS RETURN SUNDAY NIGHT AND CONTINUE THROUGH MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001. OH...NONE. PA...NONE. WV...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-041. && $$ SYNOPSIS...WOODRUM NEAR TERM...WOODRUM SHORT TERM...WOODRUM AVIATION...FRIES
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
153 AM EST SAT FEB 9 2013 .SYNOPSIS... COLD NORTHWESTERLY WINDS WILL BRING SCATTERED SNOW SHOWERS AND FLURRIES TO PORTIONS OF THE AREA THROUGH DAWN. HIGH PRESSURE WILL THEN BUILD IN FOR A DRY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AN ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO INCLUDE SCATTERED FLURRIES ACROSS MUCH OF THE AREA UNTIL DAWN AND CUT DOWN ADDITIONAL SNOWFALL TOTALS FOR THE RIDGES TO AN INCH. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SHIFTING EAST OF THE AREA AND MERGING WITH A COASTAL LOW OVER NEW ENGLAND. AT THE SURFACE...A BROAD AREA OF HIGH PRESSURE EXTENDS ACROSS THE GREAT LAKES AND OHIO VALLEY WITH A 976MB NOR`EASTER OFF THE NEW ENGLAND COAST. BETWEEN THE TWO FEATURES...THE UPPER OHIO VALLEY IS IN A NORTH-NORTHWESTERLY FLOW WITH A TIGHTENED PRESSURE GRADIENT. WITH LAKE ERIE PARTIALLY FROZEN OVER...A LAKE EFFECT FETCH FROM HURON IS ALLOWING FOR LINGERING FLURRIES FOR THE LOWLANDS AND UPLOPING SNOW SHOWERS FOR THE RIDGES THIS MORNING. TODAY AND TONIGHT...MODELS ARE IN AGREEMENT THAT A BROAD 500MB RIDGE ALONG WITH SURFACE HIGH WILL SLIDE ACROSS THE OHIO VALLEY. THIS WILL ALLOW FOR DRIER LOW-LEVEL AIR TO ADVECT INTO THE AREA...BRINGING AN END TO FLURRIES AROUND DAWN AND UPSLOPING BY AROUND 15Z TODAY. WAA AND SUBSIDENCE ALOFT WILL ALLOW FOR CLOUDS TO BEGIN TO DECREASE IN COVERAGE THIS AFTERNOON WITH SKIES CLEARING BY TONIGHT. FOR TEMPS...HIGHS TODAY ARE FAIRLY CLOSE TO LAMP GUIDANCE AND RANGE FROM THE MID 20S NORTH OF THE I-80 CORRIDOR AND ACROSS THE LAUREL HIGHLANDS/ALLEGHENY FRONT TO THE MID 30S ACROSS PORTIONS OF EASTERN OHIO AND NORTHERN WV. CLEAR SKIES WITH A HIGH CENTERED EAST OF THE AREA TONIGHT WILL ALLOW FOR RADIATIONAL COOLING OVERNIGHT...ESPECIALLY EAST OF PITTSBURGH. THUS...LOWS TONIGHT RANGE FROM THE SINGLE DIGITS IN FOREST/JEFFERSON/VENANGO COUNTIES TO NEAR 20 IN PORTIONS OF EASTERN OHIO. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... UPR RDG DOMINATES THE ERN CONUS ON SUN...WITH SELY RETURN FLOW DVLPG ON WRN EDGE OF SFC HIPRES. MODEST WARMTH IN THE MID-UPR 40S XPCD UNDER SCT-BKN CLDS. GUIDANCE IS QUITE CONSISTENT IN STRENGTHENING AN UPR LOW OVER THE NRN PLNS ON SUN. STG SLY LOW-LVL JET WILL DVLP IN ADVC OF THIS WAVE...WHICH WILL ADVCT VERY WARM AIR NWD INTO THE RGN SUN NGT. WDSPRD RAIN XPCD TO FORM IN THIS WARM AIR ADVCTN PATTERN...SO POPS WERE INCRD TO CATEGORICAL SUN NGT AREA WIDE IN TANDEM WITH PASSAGE OF VORT MAX. TEMPS IN NERN ZONES AND SHELTERED VLYS OF RDG ZONES MAY DROP BLW FRZG PRIOR TO ONSET OF PCPN. AS A RESULT...FRZG RAIN APPEARS A PROBABLE SCENARIO IN THESE AREAS...SPCLY LATE SUN NGT. ADZY MAY BE NEEDED BY FUTURE SHIFTS TO HIGHLIGHT THIS CONCERN. RAIN WILL CLR OUT MON AFTN AS DRY AIR BCMS ENTRAINED INTO THE WAVE. ENCROACHING COLD AIR AT H8 AND H9 WILL PERMIT A CHG TO SNOW MON AFTN-TUE. UNCERTAINTY RMNS IN DVLPMT OF ANY PCPN IN THE WAKE OF THIS WAVE...SO POPS RMN LOW. && .LONG TERM /TUESDAY THROUGH FRIDAY/... GFS AND ECMWF BOTH DEPICT A WAVE EJECTING FROM SRN PLNS TUE NGT. THE FORMER MODEL AMPLIFIES THIS WAVE AS IT CROSSES THE SRN APLCNS WHILE THE LATTER IS MORE PROGRESSIVE. IF THE GFS IS CORRECT... A COASTAL LOW WILL DVLP AS THIS WAVE APRCHS THE COAST...AND PCPN WILL SPREAD NWD INTO AT LEAST SRN PORTIONS OF THE FCST AREA. IF THE ECMWF IS CORRECT...THE FCST AREA LKLY WILL RMN DRY. ATTM... HAVE KEPT POPS BLW MEX NUMBERS...BUT SLGTLY HIGHER THAN THEY WERE IN PREV FCST. ANY PCPN DURG THIS TIME WILL BE SNOW OWING TO PERSISTENT COLD AIR. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... LOW LEVEL INSTABILITY AND MOISTURE SHOULD ALLOW FOR SCATTERED SNOW SHOWERS TO CONTINUE WITH COLD ADVECTION INTO THE MORNING HOURS. LOW LEVEL SATURATION CAPS OUT AROUND 2 KFT ACROSS THE AREA...SO MVFR STRATUS SHOULD REMAIN THROUGH THE MORNING HOURS. HOWEVER...AFTER ROUGHLY 17Z...THE EROSION OF THE INVERSION AS WELL AS DRIER BOUNDARY LAYER AIR SHOULD ALLOW EVERYONE TO SCATTER OUT AND EVENTUALLY CLEAR...YIELDING VFR CONDITIONS BY AFTERNOON. FRIES .OUTLOOK.../SATURDAY THROUGH WEDNESDAY/... WAA ALOFT AND EXITING EAST COAST SFC LOW WILL SHIFT THE MVFR CLOUD DECK EASTWARD SATURDAY MORNING. SKIES WILL SLOWLY CLEAR FROM WEST TO EAST DURING THE AFTERNOON. VFR CONDITIONS EXPECTED THROUGH SUNDAY. RESTRICTIONS RETURN SUNDAY NIGHT AND CONTINUE THROUGH MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001. OH...NONE. PA...NONE. WV...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-041. && $$ SYNOPSIS...WOODRUM NEAR TERM...WOODRUM AVIATION...FRIES
AREA FORECAST DISCUSSION
NWS GAYLORD MI
130 PM EST SAT FEB 9 2013 .SYNOPSIS... ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE REGION THROUGH EARLY SUNDAY. BEYOND THAT...A STORM SYSTEM WILL ORGANIZE OVER THE PLAINS STATES AND PUSH NORTHEAST TOWARDS THE GREAT LAKES. THIS WILL BRING A WINTRY MIX OF RAIN...SNOW...SLEET...AND FREEZING RAIN TO THE REGION BY LATE SUNDAY AND SUNDAY NIGHT. PRECIPITATION WILL CHANGE BACK TO ALL SNOW ON DURING THE DAY MONDAY AS COOLER AIR MOVES BACK INTO THE REGION. && .UPDATE... ISSUED AT 129 PM EST SAT FEB 9 2013 GOING FORECAST STILL IN GOOD SHAPE. REMAINING LAKE CLOUDS OVER LAKES MICHIGAN AND HURON STILL WELL OFFSHORE FROM LOWER MICHIGAN THANKS TO LAND BREEZE COMPONENT...LEAVING ABUNDANT SUNSHINE AND RAPIDLY WARMING TEMPS ACROSS NRN LOWER MICHIGAN. UPPER MICHIGAN GETTING RIPPED OFF HOWEVER...AS SOUTHERLY MEAN LOW LEVEL WIND IS DRAGGING LAKE CLOUDS UP THROUGH A GOOD PART OF EASTERN UPPER. NO RECENT SIGNS OF SNOW SHOWERS HOWEVER. LAKE CLOUDS OFF LAKE MICHIGAN MAY EVENTUALLY MAKE A PUSH TOWARD NW LOWER MICHIGAN AS WE GET MORE OF A WESTERLY COMPONENT. BUT THAT LOOKS TO BE A NUMBER OF HOURS OFF STILL. UPDATE ISSUED AT 1044 AM EST SAT FEB 9 2013 CLEAR AND COLD FOR A GOOD PART OF THE CWA THIS MORNING. BUT...WITH SHALLOW LAKE INSTABILITY LINGERING...DO HAVE LAKE CLOUDS/SNOW SHOWERS TO ADDRESS. SATELLITE IMAGERY REVEALING AMPLE LAKE CLOUDS OVER LAKES MICHIGAN AND HURON THIS MORNING STREAMING INTO PARTS OF EASTERN UPPER MICHIGAN WITH THE SOUTHERLY LOW LEVEL FLOW NOW DEVELOPING. BUT WITH A STRONG INVERSION UP THROUGH 5K FEET THIS MORNING AND 850 MB TEMP OF -6C...LAKE CLOUDS ARE VERY SHALLOW. NONETHELESS...MANISTIQUE (KISQ) REPORTED M1/4SM SN ABOUT AN HOUR AGO...LIKELY VERY FINE SNOW EFFECTIVELY REDUCING VSBYS. NO EVIDENCE ON RADAR...PUNCTUATING JUST HOW SHALLOW THE CONVECTION IS. REST OF TODAY...SOUTHERLY FLOW WILL INCREASE THROUGH THE BALANCE OF THE DAY ADVECTING MUCH WARMER LOW LEVEL AIR INTO THE GREAT LAKES (0C 850MB LINE EDGING INTO LOWER MICHIGAN BY 00Z). SHOULDN/T SEE MUCH IN THE WAY OF INLAND CU DEVELOPMENT TODAY (TO DRY AND INVERSION TO STRONG). BUT...REMAINING SHALLOW LAKE CLOUDS WILL CONTINUE TO GET SHOVED INTO UPPER MICHIGAN THROUGH MUCH OF THE DAY...PARTICULARLY OFF LAKE MICHIGAN WITH A SLIGHT WESTERLY COMPONENT TO THE WIND. QUESTION IS WHETHER THERE WILL BE ENOUGH OF A WESTERLY COMPONENT TO PUSH CLOUDS INTO THE MBL/FKS/TVC AREA THIS AFTERNOON. PROBABLY EVENTUALLY...BUT LATER IN THE AFTERNOON AFTER WE LOSE THE LAND BREEZE COMPONENT AND GET A STRONGER WESTERLY COMPONENT TO THE MEAN LOW LEVEL WIND. WILL TREND THE SKY FORECASTS IN THAT DIRECTION. IN ADDITION...HAVE ADDED SCT POPS FOR LIGHT SNOW SHOWERS TO A SLIVER OF WESTERN MACKINAC COUNTY THIS MORNING TO ACCOUNT FOR NUISANCE LAKE EFFECT SNOW UP THAT WAY. THINK THAT AS WE CONTINUE TO WARM ALOFT/STRENGTHEN THE INVERSION THAT EVENTUALLY THE SNOW WILL SHUT OFF...HOPEFULLY BY AFTERNOON. UPDATE ISSUED AT 642 AM EST SAT FEB 9 2013 STILL QUITE CHILLY BUT (MAINLY) QUIET OUT THERE. FLURRIES PERSIST NEAR ROGERS CITY...AND SOME FOG IS SEEN IN SOUTHERN SECTIONS OF THE FORECAST AREA. NEITHER OF THESE WILL LAST MUCH PAST DAYBREAK. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH IMPACT WEATHER POTENTIAL: NIL. OVERVIEW: SURFACE RIDGE AXIS DIRECTLY OVER THE REGION EARLY THIS MORNING WITH IMPRESSIVE NOR`EASTER JUST OFF THE NEW ENGLAND COAST. NORTHERLY FLOW ON THE WESTERN EDGE OF THIS SYSTEM HAS FALLEN APART WITH THE ARRIVAL OF THE SURFACE RIDGE...WITH LOCAL LAND BREEZES TAKING OVER GIVEN A TERRIFIC NIGHT OF RADIATIONAL COOLING UNDER CLEAR SKIES AND FRESH SNOWPACK. COLDEST TEMPS NEARING -15F AS OF THIS WRITING. THROUGH DAYBREAK: LAKE HURON STRATOCU CONTINUES TO PLAGUE THE IMMEDIATE COASTLINE...WITH PZQ/OSC OCCASIONALLY REPORTING A FEW FLURRIES. WILL MENTION FLURRIES FOR THE NEXT FEW HOURS...BUT EXPECT THIS CLOUDINESS TO WANE AS WEAKENING/BACKING BOUNDARY LAYER FLOW ALONG WITH WARMING TEMPS SLOWLY ERODES THE CLOUDINESS...AS WELL AS PUSHING IT OFFSHORE. TEMPERATURES WILL CONTINUE TO FALL...EXPECT A FEW OF THE COLDEST SPOTS TO MAKE A RUN AT -20F BY DAYBREAK...BUT -10- +5F MOST EVERYWHERE ELSE. THIS HAS CAUSED SOME PATCHY INLAND GROUND FOG AS OF 08Z...AND WILL CARRY MENTION THROUGH DAYBREAK. TODAY: SHORTWAVE RIDGING CONTINUES TO BUILD INTO THE REGION AS NORTHEASTERN TROUGH PULLS INTO THE ATLANTIC. PRIMARY FEATURE OF NOTE FOR TODAY IS SHORTWAVE CURRENTLY OVER SOUTHERN MANITOBA AND PUSHING EAST. SOUTH OF THIS FEATURE...SOME MID-UPPER LEVEL /I290K/ ISENTROPIC ASCENT IS HELPING TO FUEL SOME HIGH LEVEL CLOUDINESS AND WHILE HEIGHTS WILL BUILD OVER OUR REGION TODAY...EXPECT THAT SOME OF THIS CLOUDINESS WILL FILTER THE SUN FOR MOST AREAS. ALSO OF SOME CONCERN WILL BE THE LAKE CLOUDINESS THAT CONTINUES EARLY THIS MORNING OVER LAKE HURON...AND TO A LESSER EXTENT LAKE MICHIGAN. NEAR TERM RAP GUIDANCE IS FAR TOO PESSIMISTIC WITH CLOUDS...WITH OUR LOCAL IN HOUSE WRF LOOKING MORE REASONABLE. WITH THE SURFACE RIDGE MOVING EAST OF THE REGION TODAY...EXPECT SOUTHERLY FLOW TO SLOWLY BECOME ESTABLISHED AS THE DAY GOES ON...WHICH SHOULD HELP KEEP ANY LAKE HURON CLOUDINESS AT BAY...BUT WILL ALLOW ANY LAKE MICHIGAN CLOUDINESS TO BRUSH THE COAST OF NW LOWER...WITH MORE OF AN IMPACT OVER WESTERN CHIP/MACK. WILL CARRY THE GREATEST CLOUD COVER HERE...BUT EXPECT THAT EVEN HERE A DECENT AMOUNT OF SUN WILL BE SEEN. TEMPS: T9 AROUND -8C SUGGESTS THAT WE COULD MAKE A RUN TOWARDS 30F TODAY IN SOME SPOTS...PARTICULARLY WITH THE AID OF A GOOD DEAL OF SUNSHINE. TWEAKED CONSENSUS TEMPERATURES UP JUST A TAD...YIELDING MID 20S OVER EASTERN UPPER...WITH UPPER 20S OVER NORTHERN LOWER. TONIGHT: HIGH PRESSURE CONTINUES TO SETTLE SOUTH AND EAST OF THE REGION WITH SOUTHERLY WINDS BEGINNING TO DEVELOP AHEAD OF OUR NEXT WEATHER MAKER. PRIMARY CONCERN FOR THE OVERNIGHT IS WILL THE STRENGTH OF THE LLEVEL FLOW AND THUS IT/S IMPACT ON TEMPERATURES GIVEN ONLY LIMITED CLOUDINESS /SOME HIGH STUFF...WITH LOWER CLOUDS OVER WESTERN CHIP-MACK COURTESY OF FLOW OFF LAKE MICHIGAN/. THESE SCENARIOS TEND TO FAVOR DECOUPLING FOR AT LEAST THE FIRST HALF OF THE NIGHT...PARTICULARLY SOUTHEAST OF A CAD-APN LINE. THUS...WILL LOWER CONSENSUS TEMPS SOME IN THIS AREA...WHICH WILL LIKELY ALLOW SOME SPOTS /E.G. MIO..WEST BRANCH/ TO REACH THE SINGLE DIGITS WITH TEENS TO THE NORTH AND WEST OF THIS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 312 AM EST SAT FEB 9 2013 AN UPPER LOW NOW IN THE SOUTHERN GREAT BASIN WILL STEADILY EJECT ENE-WARD...REACHING THE NORTHERN LAKES ON MONDAY. NORTHERN STREAM ENERGY WILL DIVE SOUTHWARD BEHIND THE LOW...BUT (THANKFULLY) NOT PHASE WITH IT...RESULTING IN UPPER TROFFING OVER THE SOUTHERN ROCKIES INTO MONDAY NIGHT. THE 500MB CIRC WILL BE OPENING UP AS IT CROSSES THE REGION...STRONGLY SUGGESTING THAT THE BACKSIDE/ WRAPAROUND PORTION OF THE STORM WILL NOT PACK A TON OF PUNCH. THE FRONT SIDE/WARM ADVECTION PORTION OF THE STORM IS THE BIG ISSUE... WITH A PLETHORA OF PRECIP TYPES FEASIBLE. PRECIP ISSUES ARE AT THE FOREFRONT BEGINNING SUNDAY AFTERNOON. MODELS...PER HPC...WILL STEER THE FORECAST AWAY FROM THE SOMEWHAT DEEPER/MORE NORTHERLY/SLOWER 00Z NAM SOLUTION. THE GFS/ECMWF OFFER REASONABLY CLOSE AND BLENDABLE SOLUTIONS. THE CONSENSUS FAVORS A SOMEWHAT FASTER PUSH OF PRECIP INTO THE AREA THAN EARLIER FORECAST. SUNDAY...500MB LOW MOVES FROM S CENTRAL NEB TO S CENTRAL MN...WHILE THE DOWNSTREAM RIDGING MOVES FROM THE CENTRAL TO EASTERN GREAT LAKES. SURFACE LOW IS NEARLY STACKED (JUST SOUTH OF) THE 500MB CIRC...AND WILL FILL VERY SLIGHTLY (990 TO 992MB). A CONSIDERABLE SURGE IN WARM/MOIST ADVECTION WILL BE SEEN IN MI...ESPECIALLY IN THE AFTERNOON. WEAK ISENTROPIC ASCENT (295K SURFACE) IS ALREADY PRESENT AT 12Z...BUT RAMPS UP SUBSTANTIALLY AS THE DAY PROCEEDS. THE AIRMASS BELOW 650MB IS INITIALLY DRY (DEW PT DEPRESSIONS TO 30C)...BUT WE WILL ERODE THAT IN THE MORNING...AND ANNIHILATE IT IN THE AFTERNOON (ESPECIALLY AFTER 21Z). LATE-DAY POPS WILL RANGE FROM LIKELY/ CATEGORICAL IN THE WEST HALF OF THE FORECAST AREA...TO CHANCE IN THE ST MARYS VALLEY AND THE NE LOWER MI COAST. P-TYPE...GFS BUFR SOUNDINGS SUPPORT MUCH OF OUR EARLIER THINKING. THE NW LOWER MI COAST...AIDED BY A DOWNSLOPING SE WIND AND STRONGER WARM ADVECTION...SHOULD BE JUST ABOUT ALL RAIN. BY THE TIME YOU GET UP TOWARD THE STRAITS (PLN)...SOME SLEET COULD ENTER THE PICTURE (WITH THE WARM NOSE ONLY TO 3C AND SOME EVAP COOLING STILL POSSIBLE)...BUT SURFACE TEMPS STILL LOOK TO BE ABOVE FREEZING. FOR EASTERN UPPER...SNOW WILL BE THE MAIN PRIMARY P-TYPE THRU 00Z (UP TO HALF AN INCH IN WESTERN MACKINAC CO...LESS ELSEWHERE). THE HIGH TERRAIN OF NORTH CENTRAL LOWER IS THE MAIN POTENTIAL HEADACHE (GIVEN QPF WILL BE SMALL IN EASTERN SECTIONS). HERE...GFS BUFR SOUNDINGS ARE COMFORTABLY IN THE PL/FZRA CATEGORY (THOUGH GFS GUIDANCE TEMPS ARE WARMER THAN THE RAW SOUNDINGS SHOW...LOWER 30S VS UPPER 20S). WILL GO WITH PRIMARILY RA/FZRA/PL...AND LESS THAN A TENTH OF AN INCH OF ICE. MAX TEMPS 30 TO 40F. INCREASING SE/ESE WIND WILL BE STRONGEST IN EASTERN UPPER. SUN NIGHT...LARGELY STACKED LOW HOLDS STEADY-STATE AS IT MOVES TOWARD S CENTRAL UPPER MI. HEAVIEST PRECIP OF THE EVENT WILL BE SUNDAY EVENING...BEFORE THE WARM CONVEYOR BELT MOVES EAST AND THE MID-LEVEL DRY SLOT ARRIVES. 1000-850MB COLD ADVECTION ALSO BEGINS OVERNIGHT. EXCELLENT POTENTIAL FOR A THIRD TO TWO-THIRDS OF AN INCH OF LIQUID EQUIV PRECIP ACROSS THE FORECAST AREA BETWEEN LATE SUNDAY AFTERNOON INTO EVENING. HEAVIEST WILL BE NORTH OF THE ONCOMING WARM FRONT...IN FAR NORTHERN LOWER AND EASTERN UPPER. P-TYPE...IN EASTERN UPPER...MAINLY SNOW IN THE EVENING...TURNING TO FLURRIES/FZDZ OVERNIGHT AS MID-LEVELS DRY. SLEET MIXING IN NEAR LAKES MI/HURON. SNOW-LIQUID RATIOS POOR...GIVEN DEEP LAYER WARMER THAN -10C (UP TO 600MB)...AND MAX ASCENT NEAR 750MB/-5C. THAT WON/T PRECLUDE AN EVENT TOTAL OF 2-5 INCHES THERE. NORTHERN LOWER...STILL ALL LIQUID NEAR LAKE MI...AND QUICKLY BECOMING ALL LIQUID (OR FREEZING) ELSEWHERE. AND WITHOUT A STRONG BLOCKING HIGH TO OUR NE TO FEED IN COOL/DRY AIR...EVEN TEMPS OVER THE HIGH TERRAIN SHOULD COME UP DURING THE EVENING. BUFR SOUNDINGS...NUMERIC GUIDANCE...AND BASIC PATTERN RECOGNITION ALL SUPPORT THIS IDEA. WILL TAKE THINGS TO RAIN/DZ ACROSS ALL OF NORTHERN LOWER DURING THE EVENING...THOUGH STILL POTENTIAL FOR UP TO A TENTH OF AN INCH OF ICE OVER THE HIGHER TERRAIN. ALL TOLD...THIS LOOKS LIKE A POTENTIAL ADVISORY EVENT FOR EASTERN UPPER (SNOW) AND THE HIGH TERRAIN OF NORTHERN LOWER (ICE). THESE HEADLINES DO NOT NEED TO BE ISSUED AT THIS TIME. BY DAYBREAK...DEEPER MOISTURE WILL BE WRAPPING BACK INTO PARTS OF NW LOWER...THOUGH THE SURFACE-BASED ABOVE-FREEZING LAYER UP THRU 900MB SHOULD STILL KEEP THINGS LIQUID. MONDAY...SURFACE LOW CROSSES EASTERN UPPER AT MIDDAY...AND WILL BE JUST NORTH OF GEORGIAN BAY BY EVENING. MAY YET BE A SMALL REMNANT CLOSED CIRC AT 500MB STACKED WITH IT BY THE END OF THE DAY. DEEPER MOISTURE FLOODS BACK INTO NORTHERN MI...BUT COLD AIR DOES NOT...WITH 850MB TEMPS HOVERING IN THE -3 TO -5C RANGE. WE/LL BE PLENTY CLOUDY AND DREARY...WITH MIXED LIGHT RAIN/SNOW/DRIZZLE. A SLOPPY INCH OR SO OF ACCUMS IS POSSIBLE. TEMPS WILL HOVER IN THE 30S ALL DAY. REST OF THE FORECAST...TIME PERMITS ONLY A SOMEWHAT CURSORY LOOK AT THESE PERIODS. THE ENERGY LEFT BACK IN THE SOUTHERN ROCKIES WILL MOVE EASTWARD...TRIGGERING MID-WEEK CYCLOGENESIS THAT IMPACTS THE GULF COAST AND MID-ATLANTIC STATES. THIS SYSTEM DOES NOT LOOK TO HAVE AN IMPACT HERE...WITH QUIET AND RELATIVELY MILD WX IN THE NORTHERN LAKES. WE AWAIT THE NORTHERN STREAM TO BECOME MORE ENERGETIC...WHICH WILL HAPPEN LATE IN THE WORK WEEK. POPS WILL INCREASE BY FRIDAY. THERE IS POTENTIAL FOR ANOTHER BIG EAST COAST STORM...AND AN INJECTION OF COLDER AIR INTO OUR NECK OF THE WOODS...FOR NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 129 PM EST SAT FEB 9 2013 SOLID VFR CONDITIONS ANTICIPATED AT THE TERMINAL SITES THROUGH THE BALANCE OF THE AFTERNOON...WITH JUST SOME HIGH CIRRUS OVERHEAD. TONIGHT...INCREASING SSW FLOW OFF THE SFC WILL BRING ABOUT MARGINAL LLWS CONDITIONS TO ALL TERMINAL SITES. BIGGER QUESTION ABOUT CLOUD COVER HOWEVER. AS WE GET MORE OF A WESTERLY COMPONENT OFF LAKE MICHIGAN...FORECAST SOUNDINGS SUGGEST THAT INCREASED LOW LEVEL MOISTURE GETS PULLED INTO NRN LOWER MICHIGAN (DEWPOINT TRACE FOLDS OVERTOP THE BOUNDARY LAYER) THROUGH THE NIGHT...SUGGESTING THE POSSIBILITY OF DEVELOPMENT OF LOW STRATUS. SO...CIG FORECAST CONFIDENCE IS NOT HIGH. HAVE INDICATED THE POTENTIAL WITH INCLUSION OF SCT LOW CLOUDS LATER THIS EVENING (BKN AT MBL). HIGHEST POTENTIAL FOR LOW CLOUD DEVELOPMENT WILL LIKELY OCCUR AT PLN/MBL/TVC WHERE LOW LEVEL FLOW TRAJECTORIES WILL BE MOST FAVORABLE OFF THE LAKE. SUNDAY...ANY LOW CLOUDS SHOULD GET PUSHED NORTHWARD/ERODE FROM THE SOUTH THROUGH THE MORNING HOURS AS STRONG LOW LEVEL WARM ADVECTION PROCEEDS. SO...ANTICIPATE A TRANSITION BACK TO VFR CONDITIONS BY NOON. && .MARINE... ISSUED AT 312 AM EST SAT FEB 9 2013 SUMMARY: GENERALLY QUIET THROUGH SUNDAY AS SURFACE HIGH PRESSURE OVER THE REGION THIS MORNING SHIFTS EAST WITH SOUTH-SOUTHEASTERLY WINDS DEVELOPING TODAY AND CONTINUING THROUGH SUNDAY AS A LOW PRESSURE SYSTEM APPROACHES THE GREAT LAKES FROM THE WEST. THIS SYSTEM WILL PASS ACROSS UPPER MICHIGAN MONDAY WITH BRISK SOUTHWEST WINDS ACROSS THE NEARSHORE WATERS GIVING WAY TO LIGHTER NORTHWESTERLY WINDS BY TUESDAY. HEADLINE POTENTIAL: FRESHENING SOUTHERLY WINDS WILL BRING NEARSHORE ZONES ALONG LAKE MICHIGAN NEAR SMALL CRAFT CRITERIA BY LATE TODAY/TONIGHT. SMALL CRAFTS BECOME LIKELY LATE SUNDAY THROUGH MONDAY AS THE AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS ACROSS UPPER MICHIGAN. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...BA SYNOPSIS...JA SHORT TERM...JA LONG TERM...JZ AVIATION...BA MARINE...JA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1045 AM EST SAT FEB 9 2013 .SYNOPSIS... ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE REGION THROUGH EARLY SUNDAY. BEYOND THAT...A STORM SYSTEM WILL ORGANIZE OVER THE PLAINS STATES AND PUSH NORTHEAST TOWARDS THE GREAT LAKES. THIS WILL BRING A WINTRY MIX OF RAIN...SNOW...SLEET...AND FREEZING RAIN TO THE REGION BY LATE SUNDAY AND SUNDAY NIGHT. PRECIPITATION WILL CHANGE BACK TO ALL SNOW ON DURING THE DAY MONDAY AS COOLER AIR MOVES BACK INTO THE REGION. && .UPDATE... ISSUED AT 1044 AM EST SAT FEB 9 2013 CLEAR AND COLD FOR A GOOD PART OF THE CWA THIS MORNING. BUT...WITH SHALLOW LAKE INSTABILITY LINGERING...DO HAVE LAKE CLOUDS/SNOW SHOWERS TO ADDRESS. SATELLITE IMAGERY REVEALING AMPLE LAKE CLOUDS OVER LAKES MICHIGAN AND HURON THIS MORNING STREAMING INTO PARTS OF EASTERN UPPER MICHIGAN WITH THE SOUTHERLY LOW LEVEL FLOW NOW DEVELOPING. BUT WITH A STRONG INVERSION UP THROUGH 5K FEET THIS MORNING AND 850 MB TEMP OF -6C...LAKE CLOUDS ARE VERY SHALLOW. NONETHELESS...MANISTIQUE (KISQ) REPORTED M1/4SM SN ABOUT AN HOUR AGO...LIKELY VERY FINE SNOW EFFECTIVELY REDUCING VSBYS. NO EVIDENCE ON RADAR...PUNCTUATING JUST HOW SHALLOW THE CONVECTION IS. REST OF TODAY...SOUTHERLY FLOW WILL INCREASE THROUGH THE BALANCE OF THE DAY ADVECTING MUCH WARMER LOW LEVEL AIR INTO THE GREAT LAKES (0C 850MB LINE EDGING INTO LOWER MICHIGAN BY 00Z). SHOULDN/T SEE MUCH IN THE WAY OF INLAND CU DEVELOPMENT TODAY (TO DRY AND INVERSION TO STRONG). BUT...REMAINING SHALLOW LAKE CLOUDS WILL CONTINUE TO GET SHOVED INTO UPPER MICHIGAN THROUGH MUCH OF THE DAY...PARTICULARLY OFF LAKE MICHIGAN WITH A SLIGHT WESTERLY COMPONENT TO THE WIND. QUESTION IS WHETHER THERE WILL BE ENOUGH OF A WESTERLY COMPONENT TO PUSH CLOUDS INTO THE MBL/FKS/TVC AREA THIS AFTERNOON. PROBABLY EVENTUALLY...BUT LATER IN THE AFTERNOON AFTER WE LOSE THE LAND BREEZE COMPONENT AND GET A STRONGER WESTERLY COMPONENT TO THE MEAN LOW LEVEL WIND. WILL TREND THE SKY FORECASTS IN THAT DIRECTION. IN ADDITION...HAVE ADDED SCT POPS FOR LIGHT SNOW SHOWERS TO A SLIVER OF WESTERN MACKINAC COUNTY THIS MORNING TO ACCOUNT FOR NUISANCE LAKE EFFECT SNOW UP THAT WAY. THINK THAT AS WE CONTINUE TO WARM ALOFT/STRENGTHEN THE INVERSION THAT EVENTUALLY THE SNOW WILL SHUT OFF...HOPEFULLY BY AFTERNOON. UPDATE ISSUED AT 642 AM EST SAT FEB 9 2013 STILL QUITE CHILLY BUT (MAINLY) QUIET OUT THERE. FLURRIES PERSIST NEAR ROGERS CITY...AND SOME FOG IS SEEN IN SOUTHERN SECTIONS OF THE FORECAST AREA. NEITHER OF THESE WILL LAST MUCH PAST DAYBREAK. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH IMPACT WEATHER POTENTIAL: NIL. OVERVIEW: SURFACE RIDGE AXIS DIRECTLY OVER THE REGION EARLY THIS MORNING WITH IMPRESSIVE NOR`EASTER JUST OFF THE NEW ENGLAND COAST. NORTHERLY FLOW ON THE WESTERN EDGE OF THIS SYSTEM HAS FALLEN APART WITH THE ARRIVAL OF THE SURFACE RIDGE...WITH LOCAL LAND BREEZES TAKING OVER GIVEN A TERRIFIC NIGHT OF RADIATIONAL COOLING UNDER CLEAR SKIES AND FRESH SNOWPACK. COLDEST TEMPS NEARING -15F AS OF THIS WRITING. THROUGH DAYBREAK: LAKE HURON STRATOCU CONTINUES TO PLAGUE THE IMMEDIATE COASTLINE...WITH PZQ/OSC OCCASIONALLY REPORTING A FEW FLURRIES. WILL MENTION FLURRIES FOR THE NEXT FEW HOURS...BUT EXPECT THIS CLOUDINESS TO WANE AS WEAKENING/BACKING BOUNDARY LAYER FLOW ALONG WITH WARMING TEMPS SLOWLY ERODES THE CLOUDINESS...AS WELL AS PUSHING IT OFFSHORE. TEMPERATURES WILL CONTINUE TO FALL...EXPECT A FEW OF THE COLDEST SPOTS TO MAKE A RUN AT -20F BY DAYBREAK...BUT -10- +5F MOST EVERYWHERE ELSE. THIS HAS CAUSED SOME PATCHY INLAND GROUND FOG AS OF 08Z...AND WILL CARRY MENTION THROUGH DAYBREAK. TODAY: SHORTWAVE RIDGING CONTINUES TO BUILD INTO THE REGION AS NORTHEASTERN TROUGH PULLS INTO THE ATLANTIC. PRIMARY FEATURE OF NOTE FOR TODAY IS SHORTWAVE CURRENTLY OVER SOUTHERN MANITOBA AND PUSHING EAST. SOUTH OF THIS FEATURE...SOME MID-UPPER LEVEL /I290K/ ISENTROPIC ASCENT IS HELPING TO FUEL SOME HIGH LEVEL CLOUDINESS AND WHILE HEIGHTS WILL BUILD OVER OUR REGION TODAY...EXPECT THAT SOME OF THIS CLOUDINESS WILL FILTER THE SUN FOR MOST AREAS. ALSO OF SOME CONCERN WILL BE THE LAKE CLOUDINESS THAT CONTINUES EARLY THIS MORNING OVER LAKE HURON...AND TO A LESSER EXTENT LAKE MICHIGAN. NEAR TERM RAP GUIDANCE IS FAR TOO PESSIMISTIC WITH CLOUDS...WITH OUR LOCAL IN HOUSE WRF LOOKING MORE REASONABLE. WITH THE SURFACE RIDGE MOVING EAST OF THE REGION TODAY...EXPECT SOUTHERLY FLOW TO SLOWLY BECOME ESTABLISHED AS THE DAY GOES ON...WHICH SHOULD HELP KEEP ANY LAKE HURON CLOUDINESS AT BAY...BUT WILL ALLOW ANY LAKE MICHIGAN CLOUDINESS TO BRUSH THE COAST OF NW LOWER...WITH MORE OF AN IMPACT OVER WESTERN CHIP/MACK. WILL CARRY THE GREATEST CLOUD COVER HERE...BUT EXPECT THAT EVEN HERE A DECENT AMOUNT OF SUN WILL BE SEEN. TEMPS: T9 AROUND -8C SUGGESTS THAT WE COULD MAKE A RUN TOWARDS 30F TODAY IN SOME SPOTS...PARTICULARLY WITH THE AID OF A GOOD DEAL OF SUNSHINE. TWEAKED CONSENSUS TEMPERATURES UP JUST A TAD...YIELDING MID 20S OVER EASTERN UPPER...WITH UPPER 20S OVER NORTHERN LOWER. TONIGHT: HIGH PRESSURE CONTINUES TO SETTLE SOUTH AND EAST OF THE REGION WITH SOUTHERLY WINDS BEGINNING TO DEVELOP AHEAD OF OUR NEXT WEATHER MAKER. PRIMARY CONCERN FOR THE OVERNIGHT IS WILL THE STRENGTH OF THE LLEVEL FLOW AND THUS IT/S IMPACT ON TEMPERATURES GIVEN ONLY LIMITED CLOUDINESS /SOME HIGH STUFF...WITH LOWER CLOUDS OVER WESTERN CHIP-MACK COURTESY OF FLOW OFF LAKE MICHIGAN/. THESE SCENARIOS TEND TO FAVOR DECOUPLING FOR AT LEAST THE FIRST HALF OF THE NIGHT...PARTICULARLY SOUTHEAST OF A CAD-APN LINE. THUS...WILL LOWER CONSENSUS TEMPS SOME IN THIS AREA...WHICH WILL LIKELY ALLOW SOME SPOTS /E.G. MIO..WEST BRANCH/ TO REACH THE SINGLE DIGITS WITH TEENS TO THE NORTH AND WEST OF THIS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 312 AM EST SAT FEB 9 2013 AN UPPER LOW NOW IN THE SOUTHERN GREAT BASIN WILL STEADILY EJECT ENE-WARD...REACHING THE NORTHERN LAKES ON MONDAY. NORTHERN STREAM ENERGY WILL DIVE SOUTHWARD BEHIND THE LOW...BUT (THANKFULLY) NOT PHASE WITH IT...RESULTING IN UPPER TROFFING OVER THE SOUTHERN ROCKIES INTO MONDAY NIGHT. THE 500MB CIRC WILL BE OPENING UP AS IT CROSSES THE REGION...STRONGLY SUGGESTING THAT THE BACKSIDE/ WRAPAROUND PORTION OF THE STORM WILL NOT PACK A TON OF PUNCH. THE FRONT SIDE/WARM ADVECTION PORTION OF THE STORM IS THE BIG ISSUE... WITH A PLETHORA OF PRECIP TYPES FEASIBLE. PRECIP ISSUES ARE AT THE FOREFRONT BEGINNING SUNDAY AFTERNOON. MODELS...PER HPC...WILL STEER THE FORECAST AWAY FROM THE SOMEWHAT DEEPER/MORE NORTHERLY/SLOWER 00Z NAM SOLUTION. THE GFS/ECMWF OFFER REASONABLY CLOSE AND BLENDABLE SOLUTIONS. THE CONSENSUS FAVORS A SOMEWHAT FASTER PUSH OF PRECIP INTO THE AREA THAN EARLIER FORECAST. SUNDAY...500MB LOW MOVES FROM S CENTRAL NEB TO S CENTRAL MN...WHILE THE DOWNSTREAM RIDGING MOVES FROM THE CENTRAL TO EASTERN GREAT LAKES. SURFACE LOW IS NEARLY STACKED (JUST SOUTH OF) THE 500MB CIRC...AND WILL FILL VERY SLIGHTLY (990 TO 992MB). A CONSIDERABLE SURGE IN WARM/MOIST ADVECTION WILL BE SEEN IN MI...ESPECIALLY IN THE AFTERNOON. WEAK ISENTROPIC ASCENT (295K SURFACE) IS ALREADY PRESENT AT 12Z...BUT RAMPS UP SUBSTANTIALLY AS THE DAY PROCEEDS. THE AIRMASS BELOW 650MB IS INITIALLY DRY (DEW PT DEPRESSIONS TO 30C)...BUT WE WILL ERODE THAT IN THE MORNING...AND ANNIHILATE IT IN THE AFTERNOON (ESPECIALLY AFTER 21Z). LATE-DAY POPS WILL RANGE FROM LIKELY/ CATEGORICAL IN THE WEST HALF OF THE FORECAST AREA...TO CHANCE IN THE ST MARYS VALLEY AND THE NE LOWER MI COAST. P-TYPE...GFS BUFR SOUNDINGS SUPPORT MUCH OF OUR EARLIER THINKING. THE NW LOWER MI COAST...AIDED BY A DOWNSLOPING SE WIND AND STRONGER WARM ADVECTION...SHOULD BE JUST ABOUT ALL RAIN. BY THE TIME YOU GET UP TOWARD THE STRAITS (PLN)...SOME SLEET COULD ENTER THE PICTURE (WITH THE WARM NOSE ONLY TO 3C AND SOME EVAP COOLING STILL POSSIBLE)...BUT SURFACE TEMPS STILL LOOK TO BE ABOVE FREEZING. FOR EASTERN UPPER...SNOW WILL BE THE MAIN PRIMARY P-TYPE THRU 00Z (UP TO HALF AN INCH IN WESTERN MACKINAC CO...LESS ELSEWHERE). THE HIGH TERRAIN OF NORTH CENTRAL LOWER IS THE MAIN POTENTIAL HEADACHE (GIVEN QPF WILL BE SMALL IN EASTERN SECTIONS). HERE...GFS BUFR SOUNDINGS ARE COMFORTABLY IN THE PL/FZRA CATEGORY (THOUGH GFS GUIDANCE TEMPS ARE WARMER THAN THE RAW SOUNDINGS SHOW...LOWER 30S VS UPPER 20S). WILL GO WITH PRIMARILY RA/FZRA/PL...AND LESS THAN A TENTH OF AN INCH OF ICE. MAX TEMPS 30 TO 40F. INCREASING SE/ESE WIND WILL BE STRONGEST IN EASTERN UPPER. SUN NIGHT...LARGELY STACKED LOW HOLDS STEADY-STATE AS IT MOVES TOWARD S CENTRAL UPPER MI. HEAVIEST PRECIP OF THE EVENT WILL BE SUNDAY EVENING...BEFORE THE WARM CONVEYOR BELT MOVES EAST AND THE MID-LEVEL DRY SLOT ARRIVES. 1000-850MB COLD ADVECTION ALSO BEGINS OVERNIGHT. EXCELLENT POTENTIAL FOR A THIRD TO TWO-THIRDS OF AN INCH OF LIQUID EQUIV PRECIP ACROSS THE FORECAST AREA BETWEEN LATE SUNDAY AFTERNOON INTO EVENING. HEAVIEST WILL BE NORTH OF THE ONCOMING WARM FRONT...IN FAR NORTHERN LOWER AND EASTERN UPPER. P-TYPE...IN EASTERN UPPER...MAINLY SNOW IN THE EVENING...TURNING TO FLURRIES/FZDZ OVERNIGHT AS MID-LEVELS DRY. SLEET MIXING IN NEAR LAKES MI/HURON. SNOW-LIQUID RATIOS POOR...GIVEN DEEP LAYER WARMER THAN -10C (UP TO 600MB)...AND MAX ASCENT NEAR 750MB/-5C. THAT WON/T PRECLUDE AN EVENT TOTAL OF 2-5 INCHES THERE. NORTHERN LOWER...STILL ALL LIQUID NEAR LAKE MI...AND QUICKLY BECOMING ALL LIQUID (OR FREEZING) ELSEWHERE. AND WITHOUT A STRONG BLOCKING HIGH TO OUR NE TO FEED IN COOL/DRY AIR...EVEN TEMPS OVER THE HIGH TERRAIN SHOULD COME UP DURING THE EVENING. BUFR SOUNDINGS...NUMERIC GUIDANCE...AND BASIC PATTERN RECOGNITION ALL SUPPORT THIS IDEA. WILL TAKE THINGS TO RAIN/DZ ACROSS ALL OF NORTHERN LOWER DURING THE EVENING...THOUGH STILL POTENTIAL FOR UP TO A TENTH OF AN INCH OF ICE OVER THE HIGHER TERRAIN. ALL TOLD...THIS LOOKS LIKE A POTENTIAL ADVISORY EVENT FOR EASTERN UPPER (SNOW) AND THE HIGH TERRAIN OF NORTHERN LOWER (ICE). THESE HEADLINES DO NOT NEED TO BE ISSUED AT THIS TIME. BY DAYBREAK...DEEPER MOISTURE WILL BE WRAPPING BACK INTO PARTS OF NW LOWER...THOUGH THE SURFACE-BASED ABOVE-FREEZING LAYER UP THRU 900MB SHOULD STILL KEEP THINGS LIQUID. MONDAY...SURFACE LOW CROSSES EASTERN UPPER AT MIDDAY...AND WILL BE JUST NORTH OF GEORGIAN BAY BY EVENING. MAY YET BE A SMALL REMNANT CLOSED CIRC AT 500MB STACKED WITH IT BY THE END OF THE DAY. DEEPER MOISTURE FLOODS BACK INTO NORTHERN MI...BUT COLD AIR DOES NOT...WITH 850MB TEMPS HOVERING IN THE -3 TO -5C RANGE. WE/LL BE PLENTY CLOUDY AND DREARY...WITH MIXED LIGHT RAIN/SNOW/DRIZZLE. A SLOPPY INCH OR SO OF ACCUMS IS POSSIBLE. TEMPS WILL HOVER IN THE 30S ALL DAY. REST OF THE FORECAST...TIME PERMITS ONLY A SOMEWHAT CURSORY LOOK AT THESE PERIODS. THE ENERGY LEFT BACK IN THE SOUTHERN ROCKIES WILL MOVE EASTWARD...TRIGGERING MID-WEEK CYCLOGENESIS THAT IMPACTS THE GULF COAST AND MID-ATLANTIC STATES. THIS SYSTEM DOES NOT LOOK TO HAVE AN IMPACT HERE...WITH QUIET AND RELATIVELY MILD WX IN THE NORTHERN LAKES. WE AWAIT THE NORTHERN STREAM TO BECOME MORE ENERGETIC...WHICH WILL HAPPEN LATE IN THE WORK WEEK. POPS WILL INCREASE BY FRIDAY. THERE IS POTENTIAL FOR ANOTHER BIG EAST COAST STORM...AND AN INJECTION OF COLDER AIR INTO OUR NECK OF THE WOODS...FOR NEXT WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 642 AM EST SAT FEB 9 2013 VFR. LLWS TVC/MBL TONIGHT. HIGH PRESSURE DIRECTLY OVERHEAD EARLY THIS MORNING. SKIES MOSTLY CLEAR BUT VERY COLD WITH CALM WINDS. LAKE EFFECT CLOUDS CONTINUE TO BE IN THE NEIGHBORHOOD OF APN...BUT AS SOUTH WINDS DEVELOP AS THE HIGH MOVES EAST...THESE WILL MOVE AWAY FROM THE FIELD. LIGHT SOUTH WINDS DEEVLOPING TODAY AND INTO TONIGHT. STRONGER WINDS JUST OFF THE DECK TONIGHT NEAR LAKE MI...AS WARMER AIR STARTS TO INVADE. THIS WILL RESULT IN LLWS AT TVC/MBL FOR PART OF TONIGHT. && .MARINE... ISSUED AT 312 AM EST SAT FEB 9 2013 SUMMARY: GENERALLY QUIET THROUGH SUNDAY AS SURFACE HIGH PRESSURE OVER THE REGION THIS MORNING SHIFTS EAST WITH SOUTH-SOUTHEASTERLY WINDS DEVELOPING TODAY AND CONTINUING THROUGH SUNDAY AS A LOW PRESSURE SYSTEM APPROACHES THE GREAT LAKES FROM THE WEST. THIS SYSTEM WILL PASS ACROSS UPPER MICHIGAN MONDAY WITH BRISK SOUTHWEST WINDS ACROSS THE NEARSHORE WATERS GIVING WAY TO LIGHTER NORTHWESTERLY WINDS BY TUESDAY. HEADLINE POTENTIAL: FRESHENING SOUTHERLY WINDS WILL BRING NEARSHORE ZONES ALONG LAKE MICHIGAN NEAR SMALL CRAFT CRITERIA BY LATE TODAY/TONIGHT. SMALL CRAFTS BECOME LIKELY LATE SUNDAY THROUGH MONDAY AS THE AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS ACROSS UPPER MICHIGAN. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...BA SYNOPSIS...JA SHORT TERM...JA LONG TERM...JZ AVIATION...JZ MARINE...JA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
642 AM EST SAT FEB 9 2013 .SYNOPSIS... ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE REGION THROUGH EARLY SUNDAY. BEYOND THAT...A STORM SYSTEM WILL ORGANIZE OVER THE PLAINS STATES AND PUSH NORTHEAST TOWARDS THE GREAT LAKES. THIS WILL BRING A WINTRY MIX OF RAIN...SNOW...SLEET...AND FREEZING RAIN TO THE REGION BY LATE SUNDAY AND SUNDAY NIGHT. PRECIPITATION WILL CHANGE BACK TO ALL SNOW ON DURING THE DAY MONDAY AS COOLER AIR MOVES BACK INTO THE REGION. && .UPDATE... ISSUED AT 642 AM EST SAT FEB 9 2013 STILL QUITE CHILLY BUT (MAINLY) QUIET OUT THERE. FLURRIES PERSIST NEAR ROGERS CITY...AND SOME FOG IS SEEN IN SOUTHERN SECTIONS OF THE FORECAST AREA. NEITHER OF THESE WILL LAST MUCH PAST DAYBREAK. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH IMPACT WEATHER POTENTIAL: NIL. OVERVIEW: SURFACE RIDGE AXIS DIRECTLY OVER THE REGION EARLY THIS MORNING WITH IMPRESSIVE NOR`EASTER JUST OFF THE NEW ENGLAND COAST. NORTHERLY FLOW ON THE WESTERN EDGE OF THIS SYSTEM HAS FALLEN APART WITH THE ARRIVAL OF THE SURFACE RIDGE...WITH LOCAL LAND BREEZES TAKING OVER GIVEN A TERRIFIC NIGHT OF RADIATIONAL COOLING UNDER CLEAR SKIES AND FRESH SNOWPACK. COLDEST TEMPS NEARING -15F AS OF THIS WRITING. THROUGH DAYBREAK: LAKE HURON STRATOCU CONTINUES TO PLAGUE THE IMMEDIATE COASTLINE...WITH PZQ/OSC OCCASIONALLY REPORTING A FEW FLURRIES. WILL MENTION FLURRIES FOR THE NEXT FEW HOURS...BUT EXPECT THIS CLOUDINESS TO WANE AS WEAKENING/BACKING BOUNDARY LAYER FLOW ALONG WITH WARMING TEMPS SLOWLY ERODES THE CLOUDINESS...AS WELL AS PUSHING IT OFFSHORE. TEMPERATURES WILL CONTINUE TO FALL...EXPECT A FEW OF THE COLDEST SPOTS TO MAKE A RUN AT -20F BY DAYBREAK...BUT -10- +5F MOST EVERYWHERE ELSE. THIS HAS CAUSED SOME PATCHY INLAND GROUND FOG AS OF 08Z...AND WILL CARRY MENTION THROUGH DAYBREAK. TODAY: SHORTWAVE RIDGING CONTINUES TO BUILD INTO THE REGION AS NORTHEASTERN TROUGH PULLS INTO THE ATLANTIC. PRIMARY FEATURE OF NOTE FOR TODAY IS SHORTWAVE CURRENTLY OVER SOUTHERN MANITOBA AND PUSHING EAST. SOUTH OF THIS FEATURE...SOME MID-UPPER LEVEL /I290K/ ISENTROPIC ASCENT IS HELPING TO FUEL SOME HIGH LEVEL CLOUDINESS AND WHILE HEIGHTS WILL BUILD OVER OUR REGION TODAY...EXPECT THAT SOME OF THIS CLOUDINESS WILL FILTER THE SUN FOR MOST AREAS. ALSO OF SOME CONCERN WILL BE THE LAKE CLOUDINESS THAT CONTINUES EARLY THIS MORNING OVER LAKE HURON...AND TO A LESSER EXTENT LAKE MICHIGAN. NEAR TERM RAP GUIDANCE IS FAR TOO PESSIMISTIC WITH CLOUDS...WITH OUR LOCAL IN HOUSE WRF LOOKING MORE REASONABLE. WITH THE SURFACE RIDGE MOVING EAST OF THE REGION TODAY...EXPECT SOUTHERLY FLOW TO SLOWLY BECOME ESTABLISHED AS THE DAY GOES ON...WHICH SHOULD HELP KEEP ANY LAKE HURON CLOUDINESS AT BAY...BUT WILL ALLOW ANY LAKE MICHIGAN CLOUDINESS TO BRUSH THE COAST OF NW LOWER...WITH MORE OF AN IMPACT OVER WESTERN CHIP/MACK. WILL CARRY THE GREATEST CLOUD COVER HERE...BUT EXPECT THAT EVEN HERE A DECENT AMOUNT OF SUN WILL BE SEEN. TEMPS: T9 AROUND -8C SUGGESTS THAT WE COULD MAKE A RUN TOWARDS 30F TODAY IN SOME SPOTS...PARTICULARLY WITH THE AID OF A GOOD DEAL OF SUNSHINE. TWEAKED CONSENSUS TEMPERATURES UP JUST A TAD...YIELDING MID 20S OVER EASTERN UPPER...WITH UPPER 20S OVER NORTHERN LOWER. TONIGHT: HIGH PRESSURE CONTINUES TO SETTLE SOUTH AND EAST OF THE REGION WITH SOUTHERLY WINDS BEGINNING TO DEVELOP AHEAD OF OUR NEXT WEATHER MAKER. PRIMARY CONCERN FOR THE OVERNIGHT IS WILL THE STRENGTH OF THE LLEVEL FLOW AND THUS IT/S IMPACT ON TEMPERATURES GIVEN ONLY LIMITED CLOUDINESS /SOME HIGH STUFF...WITH LOWER CLOUDS OVER WESTERN CHIP-MACK COURTESY OF FLOW OFF LAKE MICHIGAN/. THESE SCENARIOS TEND TO FAVOR DECOUPLING FOR AT LEAST THE FIRST HALF OF THE NIGHT...PARTICULARLY SOUTHEAST OF A CAD-APN LINE. THUS...WILL LOWER CONSENSUS TEMPS SOME IN THIS AREA...WHICH WILL LIKELY ALLOW SOME SPOTS /E.G. MIO..WEST BRANCH/ TO REACH THE SINGLE DIGITS WITH TEENS TO THE NORTH AND WEST OF THIS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 312 AM EST SAT FEB 9 2013 AN UPPER LOW NOW IN THE SOUTHERN GREAT BASIN WILL STEADILY EJECT ENE-WARD...REACHING THE NORTHERN LAKES ON MONDAY. NORTHERN STREAM ENERGY WILL DIVE SOUTHWARD BEHIND THE LOW...BUT (THANKFULLY) NOT PHASE WITH IT...RESULTING IN UPPER TROFFING OVER THE SOUTHERN ROCKIES INTO MONDAY NIGHT. THE 500MB CIRC WILL BE OPENING UP AS IT CROSSES THE REGION...STRONGLY SUGGESTING THAT THE BACKSIDE/ WRAPAROUND PORTION OF THE STORM WILL NOT PACK A TON OF PUNCH. THE FRONT SIDE/WARM ADVECTION PORTION OF THE STORM IS THE BIG ISSUE... WITH A PLETHORA OF PRECIP TYPES FEASIBLE. PRECIP ISSUES ARE AT THE FOREFRONT BEGINNING SUNDAY AFTERNOON. MODELS...PER HPC...WILL STEER THE FORECAST AWAY FROM THE SOMEWHAT DEEPER/MORE NORTHERLY/SLOWER 00Z NAM SOLUTION. THE GFS/ECMWF OFFER REASONABLY CLOSE AND BLENDABLE SOLUTIONS. THE CONSENSUS FAVORS A SOMEWHAT FASTER PUSH OF PRECIP INTO THE AREA THAN EARLIER FORECAST. SUNDAY...500MB LOW MOVES FROM S CENTRAL NEB TO S CENTRAL MN...WHILE THE DOWNSTREAM RIDGING MOVES FROM THE CENTRAL TO EASTERN GREAT LAKES. SURFACE LOW IS NEARLY STACKED (JUST SOUTH OF) THE 500MB CIRC...AND WILL FILL VERY SLIGHTLY (990 TO 992MB). A CONSIDERABLE SURGE IN WARM/MOIST ADVECTION WILL BE SEEN IN MI...ESPECIALLY IN THE AFTERNOON. WEAK ISENTROPIC ASCENT (295K SURFACE) IS ALREADY PRESENT AT 12Z...BUT RAMPS UP SUBSTANTIALLY AS THE DAY PROCEEDS. THE AIRMASS BELOW 650MB IS INITIALLY DRY (DEW PT DEPRESSIONS TO 30C)...BUT WE WILL ERODE THAT IN THE MORNING...AND ANNIHILATE IT IN THE AFTERNOON (ESPECIALLY AFTER 21Z). LATE-DAY POPS WILL RANGE FROM LIKELY/ CATEGORICAL IN THE WEST HALF OF THE FORECAST AREA...TO CHANCE IN THE ST MARYS VALLEY AND THE NE LOWER MI COAST. P-TYPE...GFS BUFR SOUNDINGS SUPPORT MUCH OF OUR EARLIER THINKING. THE NW LOWER MI COAST...AIDED BY A DOWNSLOPING SE WIND AND STRONGER WARM ADVECTION...SHOULD BE JUST ABOUT ALL RAIN. BY THE TIME YOU GET UP TOWARD THE STRAITS (PLN)...SOME SLEET COULD ENTER THE PICTURE (WITH THE WARM NOSE ONLY TO 3C AND SOME EVAP COOLING STILL POSSIBLE)...BUT SURFACE TEMPS STILL LOOK TO BE ABOVE FREEZING. FOR EASTERN UPPER...SNOW WILL BE THE MAIN PRIMARY P-TYPE THRU 00Z (UP TO HALF AN INCH IN WESTERN MACKINAC CO...LESS ELSEWHERE). THE HIGH TERRAIN OF NORTH CENTRAL LOWER IS THE MAIN POTENTIAL HEADACHE (GIVEN QPF WILL BE SMALL IN EASTERN SECTIONS). HERE...GFS BUFR SOUNDINGS ARE COMFORTABLY IN THE PL/FZRA CATEGORY (THOUGH GFS GUIDANCE TEMPS ARE WARMER THAN THE RAW SOUNDINGS SHOW...LOWER 30S VS UPPER 20S). WILL GO WITH PRIMARILY RA/FZRA/PL...AND LESS THAN A TENTH OF AN INCH OF ICE. MAX TEMPS 30 TO 40F. INCREASING SE/ESE WIND WILL BE STRONGEST IN EASTERN UPPER. SUN NIGHT...LARGELY STACKED LOW HOLDS STEADY-STATE AS IT MOVES TOWARD S CENTRAL UPPER MI. HEAVIEST PRECIP OF THE EVENT WILL BE SUNDAY EVENING...BEFORE THE WARM CONVEYOR BELT MOVES EAST AND THE MID-LEVEL DRY SLOT ARRIVES. 1000-850MB COLD ADVECTION ALSO BEGINS OVERNIGHT. EXCELLENT POTENTIAL FOR A THIRD TO TWO-THIRDS OF AN INCH OF LIQUID EQUIV PRECIP ACROSS THE FORECAST AREA BETWEEN LATE SUNDAY AFTERNOON INTO EVENING. HEAVIEST WILL BE NORTH OF THE ONCOMING WARM FRONT...IN FAR NORTHERN LOWER AND EASTERN UPPER. P-TYPE...IN EASTERN UPPER...MAINLY SNOW IN THE EVENING...TURNING TO FLURRIES/FZDZ OVERNIGHT AS MID-LEVELS DRY. SLEET MIXING IN NEAR LAKES MI/HURON. SNOW-LIQUID RATIOS POOR...GIVEN DEEP LAYER WARMER THAN -10C (UP TO 600MB)...AND MAX ASCENT NEAR 750MB/-5C. THAT WON/T PRECLUDE AN EVENT TOTAL OF 2-5 INCHES THERE. NORTHERN LOWER...STILL ALL LIQUID NEAR LAKE MI...AND QUICKLY BECOMING ALL LIQUID (OR FREEZING) ELSEWHERE. AND WITHOUT A STRONG BLOCKING HIGH TO OUR NE TO FEED IN COOL/DRY AIR...EVEN TEMPS OVER THE HIGH TERRAIN SHOULD COME UP DURING THE EVENING. BUFR SOUNDINGS...NUMERIC GUIDANCE...AND BASIC PATTERN RECOGNITION ALL SUPPORT THIS IDEA. WILL TAKE THINGS TO RAIN/DZ ACROSS ALL OF NORTHERN LOWER DURING THE EVENING...THOUGH STILL POTENTIAL FOR UP TO A TENTH OF AN INCH OF ICE OVER THE HIGHER TERRAIN. ALL TOLD...THIS LOOKS LIKE A POTENTIAL ADVISORY EVENT FOR EASTERN UPPER (SNOW) AND THE HIGH TERRAIN OF NORTHERN LOWER (ICE). THESE HEADLINES DO NOT NEED TO BE ISSUED AT THIS TIME. BY DAYBREAK...DEEPER MOISTURE WILL BE WRAPPING BACK INTO PARTS OF NW LOWER...THOUGH THE SURFACE-BASED ABOVE-FREEZING LAYER UP THRU 900MB SHOULD STILL KEEP THINGS LIQUID. MONDAY...SURFACE LOW CROSSES EASTERN UPPER AT MIDDAY...AND WILL BE JUST NORTH OF GEORGIAN BAY BY EVENING. MAY YET BE A SMALL REMNANT CLOSED CIRC AT 500MB STACKED WITH IT BY THE END OF THE DAY. DEEPER MOISTURE FLOODS BACK INTO NORTHERN MI...BUT COLD AIR DOES NOT...WITH 850MB TEMPS HOVERING IN THE -3 TO -5C RANGE. WE/LL BE PLENTY CLOUDY AND DREARY...WITH MIXED LIGHT RAIN/SNOW/DRIZZLE. A SLOPPY INCH OR SO OF ACCUMS IS POSSIBLE. TEMPS WILL HOVER IN THE 30S ALL DAY. REST OF THE FORECAST...TIME PERMITS ONLY A SOMEWHAT CURSORY LOOK AT THESE PERIODS. THE ENERGY LEFT BACK IN THE SOUTHERN ROCKIES WILL MOVE EASTWARD...TRIGGERING MID-WEEK CYCLOGENESIS THAT IMPACTS THE GULF COAST AND MID-ATLANTIC STATES. THIS SYSTEM DOES NOT LOOK TO HAVE AN IMPACT HERE...WITH QUIET AND RELATIVELY MILD WX IN THE NORTHERN LAKES. WE AWAIT THE NORTHERN STREAM TO BECOME MORE ENERGETIC...WHICH WILL HAPPEN LATE IN THE WORK WEEK. POPS WILL INCREASE BY FRIDAY. THERE IS POTENTIAL FOR ANOTHER BIG EAST COAST STORM...AND AN INJECTION OF COLDER AIR INTO OUR NECK OF THE WOODS...FOR NEXT WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 642 AM EST SAT FEB 9 2013 VFR. LLWS TVC/MBL TONIGHT. HIGH PRESSURE DIRECTLY OVERHEAD EARLY THIS MORNING. SKIES MOSTLY CLEAR BUT VERY COLD WITH CALM WINDS. LAKE EFFECT CLOUDS CONTINUE TO BE IN THE NEIGHBORHOOD OF APN...BUT AS SOUTH WINDS DEVELOP AS THE HIGH MOVES EAST...THESE WILL MOVE AWAY FROM THE FIELD. LIGHT SOUTH WINDS DEEVLOPING TODAY AND INTO TONIGHT. STRONGER WINDS JUST OFF THE DECK TONIGHT NEAR LAKE MI...AS WARMER AIR STARTS TO INVADE. THIS WILL RESULT IN LLWS AT TVC/MBL FOR PART OF TONIGHT. && .MARINE... ISSUED AT 312 AM EST SAT FEB 9 2013 SUMMARY: GENERALLY QUIET THROUGH SUNDAY AS SURFACE HIGH PRESSURE OVER THE REGION THIS MORNING SHIFTS EAST WITH SOUTH-SOUTHEASTERLY WINDS DEVELOPING TODAY AND CONTINUING THROUGH SUNDAY AS A LOW PRESSURE SYSTEM APPROACHES THE GREAT LAKES FROM THE WEST. THIS SYSTEM WILL PASS ACROSS UPPER MICHIGAN MONDAY WITH BRISK SOUTHWEST WINDS ACROSS THE NEARSHORE WATERS GIVING WAY TO LIGHTER NORTHWESTERLY WINDS BY TUESDAY. HEADLINE POTENTIAL: FRESHENING SOUTHERLY WINDS WILL BRING NEARSHORE ZONES ALONG LAKE MICHIGAN NEAR SMALL CRAFT CRITERIA BY LATE TODAY/TONIGHT. SMALL CRAFTS BECOME LIKELY LATE SUNDAY THROUGH MONDAY AS THE AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS ACROSS UPPER MICHIGAN. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JZ SYNOPSIS...JA SHORT TERM...JA LONG TERM...JZ AVIATION...JZ MARINE...JA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
319 AM EST SAT FEB 9 2013 .SYNOPSIS... ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE REGION THROUGH EARLY SUNDAY. BEYOND THAT...A STORM SYSTEM WILL ORGANIZE OVER THE PLAINS STATES AND PUSH NORTHEAST TOWARDS THE GREAT LAKES. THIS WILL BRING A WINTRY MIX OF RAIN...SNOW...SLEET...AND FREEZING RAIN TO THE REGION BY LATE SUNDAY AND SUNDAY NIGHT. PRECIPITATION WILL CHANGE BACK TO ALL SNOW ON DURING THE DAY MONDAY AS COOLER AIR MOVES BACK INTO THE REGION. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 312 AM EST SAT FEB 9 2013 HIGH IMPACT WEATHER POTENTIAL: NIL. OVERVIEW: SURFACE RIDGE AXIS DIRECTLY OVER THE REGION EARLY THIS MORNING WITH IMPRESSIVE NOR`EASTER JUST OFF THE NEW ENGLAND COAST. NORTHERLY FLOW ON THE WESTERN EDGE OF THIS SYSTEM HAS FALLEN APART WITH THE ARRIVAL OF THE SURFACE RIDGE...WITH LOCAL LAND BREEZES TAKING OVER GIVEN A TERRIFIC NIGHT OF RADIATIONAL COOLING UNDER CLEAR SKIES AND FRESH SNOWPACK. COLDEST TEMPS NEARING -15F AS OF THIS WRITING. THROUGH DAYBREAK: LAKE HURON STRATOCU CONTINUES TO PLAGUE THE IMMEDIATE COASTLINE...WITH PZQ/OSC OCCASIONALLY REPORTING A FEW FLURRIES. WILL MENTION FLURRIES FOR THE NEXT FEW HOURS...BUT EXPECT THIS CLOUDINESS TO WANE AS WEAKENING/BACKING BOUNDARY LAYER FLOW ALONG WITH WARMING TEMPS SLOWLY ERODES THE CLOUDINESS...AS WELL AS PUSHING IT OFFSHORE. TEMPERATURES WILL CONTINUE TO FALL...EXPECT A FEW OF THE COLDEST SPOTS TO MAKE A RUN AT -20F BY DAYBREAK...BUT -10- +5F MOST EVERYWHERE ELSE. THIS HAS CAUSED SOME PATCHY INLAND GROUND FOG AS OF 08Z...AND WILL CARRY MENTION THROUGH DAYBREAK. TODAY: SHORTWAVE RIDGING CONTINUES TO BUILD INTO THE REGION AS NORTHEASTERN TROUGH PULLS INTO THE ATLANTIC. PRIMARY FEATURE OF NOTE FOR TODAY IS SHORTWAVE CURRENTLY OVER SOUTHERN MANITOBA AND PUSHING EAST. SOUTH OF THIS FEATURE...SOME MID-UPPER LEVEL /I290K/ ISENTROPIC ASCENT IS HELPING TO FUEL SOME HIGH LEVEL CLOUDINESS AND WHILE HEIGHTS WILL BUILD OVER OUR REGION TODAY...EXPECT THAT SOME OF THIS CLOUDINESS WILL FILTER THE SUN FOR MOST AREAS. ALSO OF SOME CONCERN WILL BE THE LAKE CLOUDINESS THAT CONTINUES EARLY THIS MORNING OVER LAKE HURON...AND TO A LESSER EXTENT LAKE MICHIGAN. NEAR TERM RAP GUIDANCE IS FAR TOO PESSIMISTIC WITH CLOUDS...WITH OUR LOCAL IN HOUSE WRF LOOKING MORE REASONABLE. WITH THE SURFACE RIDGE MOVING EAST OF THE REGION TODAY...EXPECT SOUTHERLY FLOW TO SLOWLY BECOME ESTABLISHED AS THE DAY GOES ON...WHICH SHOULD HELP KEEP ANY LAKE HURON CLOUDINESS AT BAY...BUT WILL ALLOW ANY LAKE MICHIGAN CLOUDINESS TO BRUSH THE COAST OF NW LOWER...WITH MORE OF AN IMPACT OVER WESTERN CHIP/MACK. WILL CARRY THE GREATEST CLOUD COVER HERE...BUT EXPECT THAT EVEN HERE A DECENT AMOUNT OF SUN WILL BE SEEN. TEMPS: T9 AROUND -8C SUGGESTS THAT WE COULD MAKE A RUN TOWARDS 30F TODAY IN SOME SPOTS...PARTICULARLY WITH THE AID OF A GOOD DEAL OF SUNSHINE. TWEAKED CONSENSUS TEMPERATURES UP JUST A TAD...YIELDING MID 20S OVER EASTERN UPPER...WITH UPPER 20S OVER NORTHERN LOWER. TONIGHT: HIGH PRESSURE CONTINUES TO SETTLE SOUTH AND EAST OF THE REGION WITH SOUTHERLY WINDS BEGINNING TO DEVELOP AHEAD OF OUR NEXT WEATHER MAKER. PRIMARY CONCERN FOR THE OVERNIGHT IS WILL THE STRENGTH OF THE LLEVEL FLOW AND THUS IT/S IMPACT ON TEMPERATURES GIVEN ONLY LIMITED CLOUDINESS /SOME HIGH STUFF...WITH LOWER CLOUDS OVER WESTERN CHIP-MACK COURTESY OF FLOW OFF LAKE MICHIGAN/. THESE SCENARIOS TEND TO FAVOR DECOUPLING FOR AT LEAST THE FIRST HALF OF THE NIGHT...PARTICULARLY SOUTHEAST OF A CAD-APN LINE. THUS...WILL LOWER CONSENSUS TEMPS SOME IN THIS AREA...WHICH WILL LIKELY ALLOW SOME SPOTS /E.G. MIO..WEST BRANCH/ TO REACH THE SINGLE DIGITS WITH TEENS TO THE NORTH AND WEST OF THIS. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 312 AM EST SAT FEB 9 2013 AN UPPER LOW NOW IN THE SOUTHERN GREAT BASIN WILL STEADILY EJECT ENE-WARD...REACHING THE NORTHERN LAKES ON MONDAY. NORTHERN STREAM ENERGY WILL DIVE SOUTHWARD BEHIND THE LOW...BUT (THANKFULLY) NOT PHASE WITH IT...RESULTING IN UPPER TROFFING OVER THE SOUTHERN ROCKIES INTO MONDAY NIGHT. THE 500MB CIRC WILL BE OPENING UP AS IT CROSSES THE REGION...STRONGLY SUGGESTING THAT THE BACKSIDE/ WRAPAROUND PORTION OF THE STORM WILL NOT PACK A TON OF PUNCH. THE FRONT SIDE/WARM ADVECTION PORTION OF THE STORM IS THE BIG ISSUE... WITH A PLETHORA OF PRECIP TYPES FEASIBLE. PRECIP ISSUES ARE AT THE FOREFRONT BEGINNING SUNDAY AFTERNOON. MODELS...PER HPC...WILL STEER THE FORECAST AWAY FROM THE SOMEWHAT DEEPER/MORE NORTHERLY/SLOWER 00Z NAM SOLUTION. THE GFS/ECMWF OFFER REASONABLY CLOSE AND BLENDABLE SOLUTIONS. THE CONSENSUS FAVORS A SOMEWHAT FASTER PUSH OF PRECIP INTO THE AREA THAN EARLIER FORECAST. SUNDAY...500MB LOW MOVES FROM S CENTRAL NEB TO S CENTRAL MN...WHILE THE DOWNSTREAM RIDGING MOVES FROM THE CENTRAL TO EASTERN GREAT LAKES. SURFACE LOW IS NEARLY STACKED (JUST SOUTH OF) THE 500MB CIRC...AND WILL FILL VERY SLIGHTLY (990 TO 992MB). A CONSIDERABLE SURGE IN WARM/MOIST ADVECTION WILL BE SEEN IN MI...ESPECIALLY IN THE AFTERNOON. WEAK ISENTROPIC ASCENT (295K SURFACE) IS ALREADY PRESENT AT 12Z...BUT RAMPS UP SUBSTANTIALLY AS THE DAY PROCEEDS. THE AIRMASS BELOW 650MB IS INITIALLY DRY (DEW PT DEPRESSIONS TO 30C)...BUT WE WILL ERODE THAT IN THE MORNING...AND ANNIHILATE IT IN THE AFTERNOON (ESPECIALLY AFTER 21Z). LATE-DAY POPS WILL RANGE FROM LIKELY/ CATEGORICAL IN THE WEST HALF OF THE FORECAST AREA...TO CHANCE IN THE ST MARYS VALLEY AND THE NE LOWER MI COAST. P-TYPE...GFS BUFR SOUNDINGS SUPPORT MUCH OF OUR EARLIER THINKING. THE NW LOWER MI COAST...AIDED BY A DOWNSLOPING SE WIND AND STRONGER WARM ADVECTION...SHOULD BE JUST ABOUT ALL RAIN. BY THE TIME YOU GET UP TOWARD THE STRAITS (PLN)...SOME SLEET COULD ENTER THE PICTURE (WITH THE WARM NOSE ONLY TO 3C AND SOME EVAP COOLING STILL POSSIBLE)...BUT SURFACE TEMPS STILL LOOK TO BE ABOVE FREEZING. FOR EASTERN UPPER...SNOW WILL BE THE MAIN PRIMARY P-TYPE THRU 00Z (UP TO HALF AN INCH IN WESTERN MACKINAC CO...LESS ELSEWHERE). THE HIGH TERRAIN OF NORTH CENTRAL LOWER IS THE MAIN POTENTIAL HEADACHE (GIVEN QPF WILL BE SMALL IN EASTERN SECTIONS). HERE...GFS BUFR SOUNDINGS ARE COMFORTABLY IN THE PL/FZRA CATEGORY (THOUGH GFS GUIDANCE TEMPS ARE WARMER THAN THE RAW SOUNDINGS SHOW...LOWER 30S VS UPPER 20S). WILL GO WITH PRIMARILY RA/FZRA/PL...AND LESS THAN A TENTH OF AN INCH OF ICE. MAX TEMPS 30 TO 40F. INCREASING SE/ESE WIND WILL BE STRONGEST IN EASTERN UPPER. SUN NIGHT...LARGELY STACKED LOW HOLDS STEADY-STATE AS IT MOVES TOWARD S CENTRAL UPPER MI. HEAVIEST PRECIP OF THE EVENT WILL BE SUNDAY EVENING...BEFORE THE WARM CONVEYOR BELT MOVES EAST AND THE MID-LEVEL DRY SLOT ARRIVES. 1000-850MB COLD ADVECTION ALSO BEGINS OVERNIGHT. EXCELLENT POTENTIAL FOR A THIRD TO TWO-THIRDS OF AN INCH OF LIQUID EQUIV PRECIP ACROSS THE FORECAST AREA BETWEEN LATE SUNDAY AFTERNOON INTO EVENING. HEAVIEST WILL BE NORTH OF THE ONCOMING WARM FRONT...IN FAR NORTHERN LOWER AND EASTERN UPPER. P-TYPE...IN EASTERN UPPER...MAINLY SNOW IN THE EVENING...TURNING TO FLURRIES/FZDZ OVERNIGHT AS MID-LEVELS DRY. SLEET MIXING IN NEAR LAKES MI/HURON. SNOW-LIQUID RATIOS POOR...GIVEN DEEP LAYER WARMER THAN -10C (UP TO 600MB)...AND MAX ASCENT NEAR 750MB/-5C. THAT WON/T PRECLUDE AN EVENT TOTAL OF 2-5 INCHES THERE. NORTHERN LOWER...STILL ALL LIQUID NEAR LAKE MI...AND QUICKLY BECOMING ALL LIQUID (OR FREEZING) ELSEWHERE. AND WITHOUT A STRONG BLOCKING HIGH TO OUR NE TO FEED IN COOL/DRY AIR...EVEN TEMPS OVER THE HIGH TERRAIN SHOULD COME UP DURING THE EVENING. BUFR SOUNDINGS...NUMERIC GUIDANCE...AND BASIC PATTERN RECOGNITION ALL SUPPORT THIS IDEA. WILL TAKE THINGS TO RAIN/DZ ACROSS ALL OF NORTHERN LOWER DURING THE EVENING...THOUGH STILL POTENTIAL FOR UP TO A TENTH OF AN INCH OF ICE OVER THE HIGHER TERRAIN. ALL TOLD...THIS LOOKS LIKE A POTENTIAL ADVISORY EVENT FOR EASTERN UPPER (SNOW) AND THE HIGH TERRAIN OF NORTHERN LOWER (ICE). THESE HEADLINES DO NOT NEED TO BE ISSUED AT THIS TIME. BY DAYBREAK...DEEPER MOISTURE WILL BE WRAPPING BACK INTO PARTS OF NW LOWER...THOUGH THE SURFACE-BASED ABOVE-FREEZING LAYER UP THRU 900MB SHOULD STILL KEEP THINGS LIQUID. MONDAY...SURFACE LOW CROSSES EASTERN UPPER AT MIDDAY...AND WILL BE JUST NORTH OF GEORGIAN BAY BY EVENING. MAY YET BE A SMALL REMNANT CLOSED CIRC AT 500MB STACKED WITH IT BY THE END OF THE DAY. DEEPER MOISTURE FLOODS BACK INTO NORTHERN MI...BUT COLD AIR DOES NOT...WITH 850MB TEMPS HOVERING IN THE -3 TO -5C RANGE. WE/LL BE PLENTY CLOUDY AND DREARY...WITH MIXED LIGHT RAIN/SNOW/DRIZZLE. A SLOPPY INCH OR SO OF ACCUMS IS POSSIBLE. TEMPS WILL HOVER IN THE 30S ALL DAY. REST OF THE FORECAST...TIME PERMITS ONLY A SOMEWHAT CURSORY LOOK AT THESE PERIODS. THE ENERGY LEFT BACK IN THE SOUTHERN ROCKIES WILL MOVE EASTWARD...TRIGGERING MID-WEEK CYCLOGENESIS THAT IMPACTS THE GULF COAST AND MID-ATLANTIC STATES. THIS SYSTEM DOES NOT LOOK TO HAVE AN IMPACT HERE...WITH QUIET AND RELATIVELY MILD WX IN THE NORTHERN LAKES. WE AWAIT THE NORTHERN STREAM TO BECOME MORE ENERGETIC...WHICH WILL HAPPEN LATE IN THE WORK WEEK. POPS WILL INCREASE BY FRIDAY. THERE IS POTENTIAL FOR ANOTHER BIG EAST COAST STORM...AND AN INJECTION OF COLDER AIR INTO OUR NECK OF THE WOODS...FOR NEXT WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1236 AM EST SAT FEB 9 2013 SUMMARY: RIDGE OF HIGH PRESSURE IN CONTROL THROUGH THE PERIOD WITH EARLY MORNING FOG/STRATOCUMULUS CONCERNS GIVING WAY UNRESTRICTED CONDITIONS. RESTRICTIONS: WHILE WE HAVE SEEN MBL DEAL WITH SOME FOG LATE IN THE EVENING...LLEVEL DRYING LOOKS TO BE ADEQUATE TO KEEP ANY SUBSTANTIAL FOG FROM FORMING. SO...WHILE A FEW PATCHES OF GROUND FOG ARE POSSIBLE...LIKELIHOOD IS TOO LOW TO INCLUDE IN THIS TAF PACKAGE. OTHER CONCERN IS REGARDING LAKE CLOUDS...THAT HAVE INFLUENCED TVC AND APN. EXPECT AN IMPROVING TREND HERE AS WELL...WITH STRENGTHENING LAND BREEZE COMPONENT. THIS SHOULD YIELD PRIMARILY VFR CONDITIONS THROUGH THE TAF PERIOD /OUTSIDE OF 1-3 MORE HOURS OF MVFR CIGS IN THE VICINITY OF APN/...WITH JUST SOME HIGH CLOUDINESS FOR THE BALANCE OF THE DAY AND INTO SATURDAY EVENING. WINDS: CALM WINDS FOR THE OVERNIGHT WILL BECOME SOUTHERLY 5-10 KTS FOR THE DAY ON SATURDAY BEFORE DIMINISHING TO LESS THAN 5KTS SATURDAY EVENING. LLWS: SOME LOW END POTENTIAL FOR LLWS AT THE VERY END OF THIS TAF PERIOD WITH 2KFT WINDS STRENGTHENING TOWARDS 25-30KTS FROM THE SOUTH. GIVEN THAT ITS/ MARGINAL AND ABOUT 21 HOURS OUT...WILL REFRAIN FROM INCLUDING IN THIS TAF PACKAGE. && .MARINE... ISSUED AT 312 AM EST SAT FEB 9 2013 SUMMARY: GENERALLY QUIET THROUGH SUNDAY AS SURFACE HIGH PRESSURE OVER THE REGION THIS MORNING SHIFTS EAST WITH SOUTH-SOUTHEASTERLY WINDS DEVELOPING TODAY AND CONTINUING THROUGH SUNDAY AS A LOW PRESSURE SYSTEM APPROACHES THE GREAT LAKES FROM THE WEST. THIS SYSTEM WILL PASS ACROSS UPPER MICHIGAN MONDAY WITH BRISK SOUTHWEST WINDS ACROSS THE NEARSHORE WATERS GIVING WAY TO LIGHTER NORTHWESTERLY WINDS BY TUESDAY. HEADLINE POTENTIAL: FRESHENING SOUTHERLY WINDS WILL BRING NEARSHORE ZONES ALONG LAKE MICHIGAN NEAR SMALL CRAFT CRITERIA BY LATE TODAY/TONIGHT. SMALL CRAFTS BECOME LIKELY LATE SUNDAY THROUGH MONDAY AS THE AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS ACROSS UPPER MICHIGAN. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ SYNOPSIS...JA SHORT TERM...JA LONG TERM...JZ AVIATION...JA MARINE...JA
AREA FORECAST DISCUSSION
NWS DULUTH MN
938 PM CST SUN FEB 10 2013 .UPDATE... PRECIPITATION RATES HAVE DIMINISHED THIS EVENING FOR MUCH OF THE NORTHLAND...AND AS THAT HAS HAPPENED MORE FREEZING DRIZZLE HAS DEVELOPED. AN AREA OF HEAVIER PRECIPITATION WAS ROTATING NORTH TOWARD PRICE/SAWYER/WASHBURN COUNTIES AND MOST OBSERVATIONS UNDER THIS PRECIP HAS BEEN RAIN. GIVEN SURFACE TEMPS AND ROAD TEMPS ARE LIKELY AT OR BELOW FREEZING OVER MUCH OF THAT AREA...WE ADDED FREEZING RAIN TO THE FORECAST. THE HEAVY SNOW BAND WAS ROTATING THROUGH OUR EXTREME NORTH CENTRAL/NORTHWEST ZONES AS OF 930 PM...AND PRECIP RATES THERE SHOULD DIMINISH LATER THIS EVENING. WE KEPT ALL THE WARNINGS GOING...BUT DID MAKE SOME CHANGES TO THE EXPIRATION. WE CHANGED THE EXPIRATION OF MOST OF THE SOUTHERN HALF TO 6 AM MONDAY MORNING...HAVE THE NORTH HALF AT 18Z. THE SOUTH SHORE IS A BIT MORE OF A CHALLENGE. THE SETUP FOR LAKE EFFECT SNOW IS NOT IDEAL...AS STABILITY ISN`T AS LOW AS WE`D LIKE TO SEE. BASED ON THE POSSIBILITY OF LAKE ENHANCED SNOWFALL AS 850MB TEMPERATURES DROP IN THE AFTERNOON...WE KEPT THE EXPIRATION OF THE WARNING FOR BAYFIELD...ASHLAND AND IRON COUNTIES AT 6 PM MONDAY. THE DOUGLAS COUNTY WARNING WE CHANGED TO NOON MONDAY. LAKE ENHANCED SNOWFALL WILL NOT OCCUR THERE...BUT THERE IS A CHANCE FOR A GRAVITY WAVE INDUCED BAND OF SNOWFALL TO DEVELOP LATE TONIGHT INTO MONDAY MORNING AS WINDS TURN NORTH TO NORTHWEST. THE RAP IS SHOWING A FAIRLY STRONG GRAVITY WAVE SIGNAL...AND THE NAM BUFR SOUNDINGS SHOW A PRETTY GOOD INVERSION DEVELOPING AROUND 2300FT AGL BY 15Z. WE INCREASED SNOWFALL IN A BAND FROM NORTH CENTRAL/NORTHWEST DOUGLAS COUNTY INTO SOUTHWEST DOUGLAS/EASTERN CARLTON COUNTIES. LATER SHIFTS WILL HAVE TO MONITOR THIS CLOSELY AS WE MAY NEED TO INCREASE SNOWFALL THERE FURTHER. && .PREV DISCUSSION... /ISSUED 721 PM CST SUN FEB 10 2013/ UPDATE... THE AREA OF VERY HEAVY SNOW...WITH RATES IN EXCESS OF OF AN INCH PER HOUR HAS MOVED INTO FAR NORTHERN MINNESOTA. RADAR WAS SHOWING OTHER AREAS OF SNOW...MOST MUCH LIGHTER...FURTHER SOUTH. A FEW SPOTTERS HAVE REPORTED THE SNOW HAD ENDED FOR NOW...LIKE AT GURNEY. WE EXPECT SNOW TO CONTINUE TONIGHT WITH AMOUNTS RANGING FROM 3 TO 6 INCHES ACROSS THE FAR NORTH WHERE FORCING WILL LAST LONGER. AREAS FURTHER SOUTH WILL RANGE FROM 1 TO 4 INCHES TONIGHT...WITH FREEZING DRIZZLE OR FREEZING RAIN POSSIBLE OVER ABOUT THE SOUTHERN HALF OF THE NORTHLAND. IT WILL BE MOST LIKELY IN NORTHWEST WISCONSIN WHERE SOUNDINGS SHOW THE BEST FREEZING DRIZZLE SOUNDINGS. AN AREA OF HEAVIER PRECIPITATION WAS MOVING NORTH TOWARD NORTHERN WISCONSIN...AND OBSERVATIONS UNDER THIS AREA OF PRECIPITATION INDICATE MOSTLY RAIN...SO WE`LL HAVE TO WATCH CLOSELY AS IT MOVES FURTHER NORTH. AT THIS TIME...WE DID LEAVE ALL THE HEADLINES ALONE...WHICH EXPIRE AT 00Z TUE. WE WILL LIKELY BE ABLE TO CANCEL SOME OF THESE EARLIER...BUT WILL WAIT A BIT LONGER TO DO SO. ADDITIONAL SNOWFALL ON MONDAY LOOKS TO BE LIMITED...BUT WOULD LIKE TO SEE SOME NEW GUIDANCE BEFORE MAKING TO MANY DRASTIC CHANGES. THE EASTERN CWA COULD SEE THE SNOW LINGER LONGEST...AND ACCUMULATIONS COULD BE AN INCH OR TWO IN THE EAST. PREV DISCUSSION... /ISSUED 539 PM CST SUN FEB 10 2013/ AVIATION...00Z TAFS WIDESPREAD VLIFR/IFR CONDITIONS WILL OCCUR ACROSS MOST AREAS TONIGHT...WITH THE VLIFR CONDITIONS MOST WIDESPREAD ACROSS FAR NORTHERN MINNESOTA WHERE MANY OBSERVATIONS HAD 0.5SM OR LESS IN SNOW. THE SNOW INTENSITY WILL DIMINISH AS THE EVENING PROGRESSES FOR MOST AREAS OVERNIGHT...BUT THERE WILL STILL BE POCKETS OF HEAVIER SNOW. CONDITIONS WILL IMPROVE FURTHER ON MONDAY. EAST/NORTHEAST WILL VEER TO NORTH TO NORTHWEST BY 12Z. PREV DISCUSSION... /ISSUED 300 PM CST SUN FEB 10 2013/ SHORT TERM...TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE OVER NORTHERN IOWA WILL CONTINUE TO BRING SNOW TO MOST OF THE NORTHLAND THIS EVENING. SOME LIGHT FREEZING RAIN AND SLEET WILL STILL MIX IN WITH THE SNOW LATE THIS AFTERNOON OVER NORTHWESTERN WISCONSIN. NORTHERLY WINDS AT 15 TO 20 MPH...WITH A FEW GUSTS TO 25 MPH...ACROSS NORTHEASTERN MINNESOTA MAY LEAD TO SOME BLOWING AND DRIFTING OF THE SNOW. WINDS WILL BE STRONGER NEAR LAKE SUPERIOR. SNOW INTENSITY WILL COME DOWN A BIT AS THE LOW MOVES NORTHEASTWARD INTO WISCONSIN LATE TONIGHT. THE CENTER OF THE LOW WILL BE OVER THE UPPER PENINSULA OF MICHIGAN ON MONDAY MORNING AND LIGHT SNOW WILL PERSIST OVER THE AREA. ADDITIONAL ACCUMULATIONS DURING THE DAY ON MONDAY WILL GENERALLY BE UNDER AN INCH. WINDS WILL BECOME MORE NORTHWESTERLY ON MONDAY AND THERE WILL BE SOME LAKE ENHANCEMENT OF THE SNOW FOR THE GOGEBIC RANGE WHERE THERE COULD BE UP TO TWO ADDITIONAL INCHES OF SNOW DURING THE DAY. THE LOW PUSHES INTO EASTERN ONTARIO MONDAY NIGHT AND THE SNOW WILL END OVER MOST OF THE NORTHLAND EXCEPT FOR AREAS OF THE SOUTH SHORE OF LAKE SUPERIOR WHERE A FEW SNOW SHOWERS WILL LINGER DURING THE EVENING HOURS. HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE CENTRAL PLAINS LATE MONDAY NIGHT. LONG TERM...TUESDAY THROUGH SUNDAY. SOME LIGHT SNOW WILL BE POSSIBLE ACROSS THE AREA ON WEDNESDAY AFTERNOON...AS A LOW PRESSURE SYSTEM MOVES TO THE FARGO AREA BY 00Z THURSDAY. THE LOW WILL THEN MOVE ACROSS CENTRAL MN AND INTO NORTHERN TO CENTRAL WISCONSIN BY 12Z THURSDAY. HAVE INCREASED POPS ACROSS THE AREA FOR WEDNESDAY NIGHT AND THURSDAY AS THE MODELS ARE COMING INTO BETTER AGREEMENT CONCERNING THIS SYSTEM. THE GFS CONTINUES TO BE STRONGER THAN THE ECMWF...BUT YESTERDAY THE ECMWF DID NOT EVEN INDICATE THIS SYSTEM SO IT IS LIKELY LATCHING ONTO IT BETTER. COLDER AIR WILL DRAG SOUTHWARD BEHIND THE DEPARTING SYSTEM ON THURSDAY AND FRIDAY. GENERALLY DRY AND COOLER WEATHER IS THEN IN STORE FOR SATURDAY AND SUNDAY. OVERALL NOT TOO MUCH IN THE WAY OF PRECIPITATION THIS PERIOD WITH THE EXCEPTION OF A FEW INCHES OF SNOW BEING POSSIBLE MID WEEK. TEMPS WILL BE ABOVE NORMAL FOR MUCH OF THE EXTENDED...BUT IT WILL BE A BIT COOLER FOR THE WEEKEND. AVIATION.../18Z TAF ISSUANCE/ A WINTER STORM WILL AFFECT THE NORTHLAND DURING THE TAF PERIOD. THE STORM WILL BRING AN INCREASE IN SNOW AND POSSIBLY SOME SNOW/ICE MIX IN EASTERN AREAS. CIGS AND VSBYS WILL GENERALLY BE IN THE IFR/LIFR/VLIFR RANGE THROUGHOUT THE PERIOD...BUT TRANSITIONING TO MORE OF AN MVFR SITUATION ON MONDAY MORNING. SNOW WILL COME DOWN VERY HARD AT TIMES...WITH VSBYS LESS THAN A QUARTER MILE. && .POINT TEMPS/POPS... DLH 23 25 9 26 / 100 80 10 0 INL 18 22 7 26 / 100 90 10 0 BRD 24 26 9 27 / 100 80 10 0 HYR 26 29 10 27 / 100 90 10 0 ASX 27 29 11 27 / 100 90 20 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL NOON CST MONDAY FOR MNZ010>012- 018>021. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR MNZ025-026- 033>038. WI...WINTER STORM WARNING UNTIL NOON CST MONDAY FOR WIZ001. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR WIZ006>009. WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR WIZ002>004. && $$ SHORT TERM...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
229 PM CST SAT FEB 9 2013 .DISCUSSION... MAIN CONCERN CONTINUES TO BE THE SIGNIFICANT WINTER STORM EXPECTED TO IMPACT THE AREA FROM LATE TONIGHT INTO MONDAY. THE LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE FEATURE OF INTEREST MAKING ITS WAY THROUGH THE SOUTHERN ROCKIES AT THE CURRENT TIME... WITH A NICE RIDGE DEVELOPING AHEAD OF IT ACROSS THE NORTHERN PLAINS. THE SHORTENING WAVELENGTH BETWEEN THESE FEATURES WILL BE COINCIDENT WITH THE SYSTEM DEEPENING AND MOVING NORTHEAST TOWARD OUR AREA... AND WILL MANIFEST ITSELF IN A PERIOD OF STRONG FORCING LATE TONIGHT THROUGH THE DAY ON SUNDAY. THERE CONTINUES TO BE SOME UNCERTAINTY IN PRECIPITATION TYPE WITH THIS SYSTEM... ALTHOUGH THE 12Z GUIDANCE HAS COME INTO GOOD AGREEMENT ON TRACKING THE SURFACE LOW ACROSS IOWA AND FAR SOUTHEAST MINNESOTA AND INTO CENTRAL WISCONSIN SUNDAY INTO SUNDAY EVENING. THE REMAINING DIFFERENCES REVOLVE AROUND HOW THE THERMAL PROFILE WILL EVOLVE THROUGH THE EVENING... PARTICULARLY FROM THE SURFACE TO 925MB. THE GFS CONTINUES TO BE WARMEST IN THAT LAYER... WITH THE ECMWF... NAM... AND GEM SUGGESTING THINGS WILL BE COOLER AND MOSTLY SNOW ACROSS MOST OF THE AREA. GENERALLY FOLLOWED A BLEND OF THE ECMWF AND NAM FOR THE FORECAST DETAILS... WITH SOME ADDITIONAL RELIANCE ON THE HIGH RESOLUTION WINDOW RUNS AND LOCAL 4KM GUIDANCE. EXPECT PCPN TO OVERSPREAD THE CWFA OVERNIGHT INTO SUNDAY MORNING... WITH SOME FREEZING RAIN POSSIBLE INITIALLY ACROSS SOUTHERN AND EASTERN MINNESOTA BEFORE THE ELEVATED WARM LAYER SATURATES AND COOLS TO BELOW FREEZING WET BULB VALUES. AFTER THAT POINT... IT LOOKS LIKE THE MAIN CHANCES FOR MIXED PCPN WILL BE FROM NEAR THE TWIN CITIES SOUTH AND EAST... WHERE THE ELEVATED WARM LAYER WILL FLIRT WITH 0C AT TIMES AND NEAR SURFACE TEMPERATURES WILL BE NEAR OR A FEW DEGREES ABOVE FREEZING. THE WESTERN AND NORTHERN PORTIONS OF THE AREA LOOK TO BE SNOW FOR THE ENTIRE EVENT... AND WITH THE MAIN MID-LEVEL DEFORMATION ZONE AND ASSOCIATED FRONTOGENESIS IMPACTED THOSE AREAS... STILL EXPECT THE BEST SNOW AMOUNTS TO OCCUR OVER THE FAR WEST AND NORTHWEST PART OF THE AREA. PCPN ACROSS THE CENTRAL AND EASTERN CWFA... INCLUDING THE TWIN CITIES... WILL BE PRIMARILY FORCED BY THE SURGE OF STRONG WARM ADVECTION/ISENTROPIC LIFT SUNDAY MORNING... ALONG WITH A DECENT AREA OF UPPER DIVERGENCE IN THE LEFT EXIT REGION OF THE APPROACHING JET. THALER QG DIAGNOSTICS ARE VERY CONSISTENT BETWEEN THE VARIOUS GUIDANCE SOURCES... AND ALL PUSH A STRONG SLUG OF QG- OMEGA ACROSS THE CWFA DURING THE MORNING AND EARLY AFTERNOON HOURS. THE MID-LEVEL DRY SLOT ASSOCIATED WITH THE UPPER JET STILL LOOKS LIKE IT SHOULD IMPACT AT LEAST THE SOUTHEAST THIRD OR SO OF THE CWFA... LIKELY FROM AROUND THE TWIN CITIES METRO SOUTH/EAST... DURING THE AFTERNOON HOURS. THAT COULD BRING A PERIOD OF SOME DRIZZLE OR FREEZING DRIZZLE... BUT AT THIS POINT DIDN/T TRY TO WORK THAT INTO THE FORECAST GIVEN THE MORE SIGNIFICANT PCPN WHICH WILL OCCUR PRIOR TO THAT AND SOME SNOW WITH THE UPPER LOW AFTERWARD. AS THE DRY SLOT PUNCHES IN TOWARD THE AREA WE WILL SEE CONVECTIVELY INSTABILITY INCREASE DRAMATICALLY JUST AHEAD OF IT AS THE DRY AIR MOVES IN ABOVE THE MOIST BOUNDARY LAYER AND LOWER TROPOSPHERE. SHOWALTER INDICES ACTUALLY DIP TO AROUND OR A BIT BELOW ZERO OVER THE SOUTHEAST PORTION OF THE CWFA DURING THE AFTERNOON... SO WOULDN/T BE SURPRISED IF SOME THUNDER OCCURRED. ALSO LEFT THAT OUT OF THE FORECAST FOR NOW... BUT IT IS CERTAINLY WORTH KEEPING AN EYE ON... SINCE ANY BURST OF CONVECTION WOULD LIKELY CHANGE ANY LINGERING MIXED PCPN OVER TO SNOW AND COULD AUGMENT PCPN TOTALS ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE WINTER STORM WARNING AREA. EXPECT TO SEE SOME SNOW PERSIST INTO SUNDAY NIGHT ON THE BACKSIDE OF THE LOW... WITH SNOW SHOWERS LINGERING INTO MONDAY WITH THE CYCLONIC FLOW. THE PRESSURE GRADIENT WILL TIGHTEN LATE SUNDAY NIGHT INTO MONDAY... WITH 925MB WINDS INCREASING TO 30-40 KT ACROSS MUCH OF THE WESTERN AND SOUTHWESTERN CWFA. KEPT THE BLIZZARD WATCH GOING TO ACCOUNT FOR THE POSSIBILITY OF BLIZZARD CONDITIONS FROM THE SNOW SHOWERS AND BLOWING SNOW LATE SUNDAY NIGHT INTO MONDAY. DIDN/T WANT TO BLANKET THE ENTIRE TIME FRAME WITH A BLIZZARD WARNING... SINCE MOST OF THE SNOW WILL OCCUR SUNDAY PRIOR TO WHEN WINDS ARE EXPECTED TO INCREASE. SO... IT SEEMED THE MOST LOGICAL WAY TO DO THINGS FOR NOW WAS TO GO WITH THE WINTER STORM WARNING WHILE KEEPING A BLIZZARD WATCH FOR THE LATER TIME FRAME. RIDGING SHOULD BRING QUIET WEATHER FOR THE MIDDLE PART OF THE WEEK... WITH AN ALBERTA CLIPPER DROPPING INTO THE REGION FOR THE THURSDAY-FRIDAY TIME FRAME. INCLUDED A CHANCE OF SOME SNOW FROM THURSDAY INTO FRIDAY AS THIS SYSTEM MOVES ACROSS THE REGION. THERE REMAIN SOME DIFFERENCES BETWEEN THE ECMWF AND GFS... SO DON/T SEE MUCH REASON TO GO WITH ANYTHING MORE THAN CHANCE POPS AT THIS POINT. TEMPERATURES THROUGH THE WEEK LOOK SEASONABLE... EXCEPT BEHIND THE CLIPPER FRIDAY INTO SATURDAY WHEN BELOW NORMAL TEMPERATURES ARE EXPECTED TO RETURN TO THE AREA. && .AVIATION.../18Z TAF ISSUANCE/ /ISSUED 1217 PM CST SAT FEB 9 2013/ IFR OR LOW-END MVFR CONDITIONS TO PREVAIL THRU LATE EVENING THEN CONDITIONS BECOME IFR AND WORSE TONIGHT THRU TMRW AS A POTENT WINTER STORM ENVELOPS THE AREA. LOW CLOUDS SLOWLY SLIDING EWD WHILE LOW LEVEL FLOW IS FROM THE SOUTH. CLEARING EDGE IN WRN IA INTO EXTREME SE SD NOT EXPECTED TO MOVE THIS FAR N...SO HAVE KEPT LOW CLOUDS GOING FOR ALL SITES. GFS GUIDANCE TRIES TO BRING IN VFR CEILINGS THIS EVENING BUT AM NOT BUYING IT DUE TO SUCH LOW LEVEL MOISTURE BEING ADVECTED INTO THE REGION...SO THESE TAFS HAVE A MORE NAM/SREF FEEL. PRECIP WILL BEGIN IMPACTING THE TAF SITES ARND 06Z...THEN GRADUALLY SPREAD EWD. NRN TAF SITES /KAXN-KSTC/ SHOULD HAVE NO PROBLEM STAYING AS SNOW THE ENTIRE DURATION OF PRECIP. THE REST OF THE TAF SITES...WITH LATER START TIMES...WILL DEAL WITH A MIX OF P-TYPES UNTIL LATE SUNDAY EVENING. PRECIP THAT STARTS AS FZRA SHOULD CHANGE OVER TO SN OR SNPL AS THE COLUMN COOLS FROM THE TOP DOWN...EVEN IF SFC TEMPS ARE SEVERAL DEGREES BELOW FREEZING AT THE START. PRECIP WILL LIKELY BE HEAVY AT TIMES DURG THE DAY TMRW AS LIFT IS ENHANCED WITH THE LOW MOVING ACRS SO HAVE MAINTAIN THE OCNL 1/2SM OR 1/4SM FOR MOD-HVY SNOW. CONDITIONS WILL CERTAINLY REMAIN DEGRADED TMRW AND LIKELY THRU TMRW NIGHT. KMSP...MVFR CONDS DUE TO CEILINGS WILL CONTINUE MOST OF THE NIGHT. HAVE ALSO KEPT CEILINGS BELOW THE 017 THRESHOLD...DESPITE THAT GFS GUIDANCE TRIES TO BRING IN 040-070 CEILINGS. AM NOT GOING THAT ROUTE AFTER EXAMINING FULL SUITE OF MODEL GUIDANCE AND COLLAB WITH CWSU ZMP. CONDITIONS DROP TO IFR BEFORE DAYBREAK AS THE PRECIP IS EXPECTED TO START AS FZRA WITH SN MIXED IN WHILE THERE IS A SHALLOW WARM LAYER. THIS LAYER WILL DISSIPATE AS THE PRECIP CONTINUES...CHANGING IT TO A SNOW/SLEET MIX BY LATE MRNG. AS SOME LARGER SCALE WARMER AIR SHIFTS IN...PRECIP MAY TAKE ON A RAIN/SNOW MIX BEFORE CHANGING TO ALL SNOW LATE IN THE DAY. MAY BE A FEW BURSTS OF MOD-HVY PRECIP DURING THIS TIME. WINDS WILL BECOME SOUTHEAST THEN EAST THRU THE NEXT 30 HRS...WITH SUSTAINED SPEEDS IN THE 10-15 KT RANGE. /OUTLOOK FOR KMSP/ SUN NGT...IFR/LIFR WITH SN. NE WIND 10 KTS BCMG NW 15 KTS. MON...IFR WITH -SN EARLY...THEN MVFR WITH -SN/BLSN. NW WINDS 17G25KTS. TUE...VFR. WINDS W AT 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR BLUE EARTH-LE SUEUR-RICE-SCOTT-WASECA-WATONWAN. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET-POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT- YELLOW MEDICINE. BLIZZARD WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON FOR BROWN-CHIPPEWA-DOUGLAS-KANDIYOHI-LAC QUI PARLE-NICOLLET- POPE-REDWOOD-RENVILLE-SIBLEY-STEVENS-SWIFT-YELLOW MEDICINE. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR CARVER-MCLEOD-MEEKER-STEARNS-TODD-WRIGHT. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM CST MONDAY FOR ANOKA-BENTON-CHISAGO-HENNEPIN-ISANTI-KANABEC-MILLE LACS- MORRISON-RAMSEY-SHERBURNE-WASHINGTON. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST SUNDAY FOR FARIBAULT-FREEBORN-MARTIN-STEELE. WINTER WEATHER ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR GOODHUE. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR DAKOTA. WI...WINTER WEATHER ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE. WINTER STORM WARNING FROM 6 AM SUNDAY TO 6 AM CST MONDAY FOR BARRON-POLK-RUSK-ST. CROIX. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
558 PM CST SUN FEB 10 2013 .AVIATION...00Z KGRI TAF. STRONG NORTHWEST WIND WILL BE THE PRIMARY CONCERN FOR THE FIRST SEVERAL HOURS OF THE FORECAST...THEN SUBSIDE SOMEWHAT OVERNIGHT...BUT CONTINUE TO BE BRISK INTO MONDAY. CEILINGS WILL BE JUST IN THE MVFR RANGE...AND COULD FLUCTUATE TO VFR AT TIMES...BEFORE SCATTERING OUT FOR THE OVERNIGHT AS THE AREA OF LOW PRESSURE RESPONSIBLE FOR THE CEILINGS AND WIND CONTINUES TO MOVE OFF TO THE NORTHEAST. && .PREV DISCUSSION... /ISSUED 259 PM CST SUN FEB 10 2013/ SHORT TERM...TODAY THROUGH MONDAY NIGHT. MAIN CONCERN DURING THIS TIME PERIOD WILL BE THE WINDS BEHIND THE SURFACE LOW. OUR NORTHERN COUNTIES...WHERE SNOWFALL OCCURRED EARLIER TODAY...WILL LIKELY RUN INTO VISIBILITY RESTRICTIONS AS BLOWING SNOW OCCURS THROUGH THE EARLY EVENING HOURS. ORD HAS EXPERIENCED VISIBILITIES BETWEEN ONE AND TWO MILES SINCE ABOUT 18Z TODAY...BUT EARLIER TODAY CONDITIONS WERE BELOW HALF A MILE. ALSO...THERE WILL BE A SLIGHT CHANCE FOR SNOW THROUGH THE REMAINDER OF TODAY...MAINLY FOR OUR NORTHERN COUNTIES. AT 20Z...THE RAP INDICATED A 500MB LOW APPROXIMATELY CENTERED OVER SIOUX FALLS SOUTH DAKOTA. THE SURFACE LOW WAS DIRECTLY UNDER THE UPPER LEVEL LOW...RESULTING IN A STACKED TROUGH WHICH IS NOW EXITING THE CENTRAL PLAINS. BEHIND THE SURFACE LOW...HEIGHT RISES ARE RESULTING IN A SHARP PRESSURE GRADIENT OVER THE OUTLOOK AREA. NORTHWESTERLY WIND SPEEDS OF 30 MPH WERE EXPERIENCED OVER NEARLY THE ENTIRE CWA. GUSTS WERE REACHING THE MID TO UPPER 40S...WITH ONLY A COUPLE SITES REACHING 50 MPH. THE WINTER WEATHER ADVISORY FOR BLOWING SNOW WILL CONTINUE UNTIL 9 PM TONIGHT TONIGHT. THIS WILL LIKELY NEED TO BE CONVERTED TO A WIND ADVISORY IF VISIBILITIES RECOVERY LATER TODAY. THE WIND ADVISORY COUNTIES UNTIL 9 PM...AS MODELS ARE NOT DEPICTING ANY LETTING UP OF THE PRESSURE GRADIENT BEFORE THEN. THE WIND ADVISORY MAY NEED TO BE EXTENDED FOR OUR EASTERN COUNTIES IF CONDITIONS DO NO EASE UP LATER TONIGHT. WIND SPEEDS WILL BEGIN TO RELAX AFTER MIDNIGHT AS THE PRESSURE GRADIENT EASES OVER THE REGION. A NORTHWESTERLY WIND COMPONENT WILL BE REALIZED OVER THE ENTIRE SHORT TERM PERIOD. HIGH TEMPERATURES FOR TOMORROW WILL BE RELATIVELY CLOSE TO NORMAL FOR THIS TIME OF YEAR. ON THE OTHER HAND...LOW TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR. LONG TERM...MONDAY NIGHT THROUGH SUNDAY...WEAK ZONAL FLOW IS EXPECTED ACROSS THE REGION TO BEGIN THE EXTENDED PERIODS AS THE VIGOROUS UPPER LEVEL LOW THAT MOVED ACROSS THE LOCAL AREA THIS MORNING APPROACHES THE EASTERN SEABOARD AND A SECOND UPPER LEVEL LOW TRACKS ACROSS THE DESERT SOUTHWEST. AT THE SAME TIME A WEAK UPPER LEVEL SHORTWAVE IS EXPECTED TO EXTEND ACROSS THE LOCAL AREA FROM THE NORTH...PROVIDING AMPLE MID LEVEL CLOUD COVER DURING THE OVERNIGHT HOURS MONDAY INTO TUESDAY MORNING...BUT WITH MINIMAL FORCING AND VERY LIMITED LOW LEVEL MOISTURE...DO NO EXPECT ANY SORT OF PRECIPITATION UNDER THIS SCENARIO. AS THE AFOREMENTIONED UPPER LEVEL ACROSS THE DESERT SOUTHWEST MOVES INTO THE SOUTHERN PLAINS TUESDAY AFTERNOON...THE UPPER LEVEL FLOW PATTERN WILL BECOME MORE AMPLIFIED...AS A RIDGE OF HIGH PRESSURE WORKS ITS WAY TOWARDS THE WEST COAST. THIS WILL ESTABLISH A NORTHWESTERLY FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS BY WEDNESDAY...WITH MULTIPLE QUICK PASSING UPPER LEVEL DISTURBANCES EXPECTED TO TRAVERSE THE PLAINS. WITH THE QUICK MOVING NATURE OF THESE DISTURBANCES AND DRY LOW LEVELS OF THE ATMOSPHERE...DO NOT THINK MORE THAN FLURRIES WILL BE REALIZED THROUGH THE END OF THE WEEK...WITH THE BEST GUEST AT TIMING BEING DURING THE DAY ACROSS THE NORTHWEST THURSDAY...AND ACROSS ALL AREAS ON FRIDAY. THE FIRST OF THESE DISTURBANCE WILL BE ACCOMPANIED BY A SURFACE COLD FRONT...WHICH IS EXPECTED TO KNOCK TEMPERATURES DOWN 10+ DEGREES F ON THURSDAY...WITH THIS COOLER...YET SEASONAL AIRMASS THEN EXPECTED TO PERSIST ACROSS THE LOCAL ARE THROUGH THE END OF THE WEEK. AHEAD OF THE FRONT...WEDNESDAY AFTERNOON APPEARS TO BE THE NICEST DAY OF THE WEEK...WITH A LIGHT DOWNSLOPING COMPONENT TO THE WINDS LIKELY HELPING TEMPERATURES CLIMB TO NEAR 50 DEGREES. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR NEZ041-047>049- 060>064-072>077-082>087. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR NEZ039- 040-046. KS...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR KSZ005>007-017>019. && $$ AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1124 PM CST FRI FEB 8 2013 .UPDATE... .AVIATION... AN INVERTED TROF/STATIONARY FRONT WILL SET UP ACROSS WRN NEB TONIGHT AND REMAIN STATIONARY SATURDAY. WEST OF THE FRONT...MVFR/IFR CIGS WILL DEVELOP. THE FRONT WILL CREEP EAST LATE SATURDAY AFTN/EVENING AND BECOME THE FOCUS FOR WIDESPREAD IFR/LIFR SATURDAY EVENING. EAST OF THE FRONT...SCATTERED TSTMS ARE EXPECTED SATURDAY EVENING. && .PREV DISCUSSION... /ISSUED 512 PM CST FRI FEB 8 2013/ UPDATE... AVIATION... THE RUC IS DEVELOPING STRATUS WITH IFR/MVFR CIGS FROM THE NORTH AND EAST OVERNIGHT. BEST GUESS ON KVTN IS 15Z. SO MVFR IS EXPECTED TO DEVELOP ALONG HIGHWAY 20 AND ALONG AND EAST OF HIGHWAY 183 LATE TONIGHT OR EARLY SATURDAY AM. A SECOND AREA OF MVFR CIGS SHOULD MOVE UP FROM THE SOUTH SATURDAY AFTN AND ENCROACH ON KLBF AROUND 21Z. PREV DISCUSSION... /ISSUED 356 PM CST FRI FEB 8 2013/ SHORT TERM...(THIS EVENING THROUGH SATURDAY) SOUTH WINDS WILL DIMINISH OVERNIGHT...THEN BECOME MORE SOUTHEAST TO EAST SATURDAY AS SURFACE LOW PRESSURE STARTS TO DEVELOP ACROSS EASTERN COLORADO. WILL CONTINUE THE SLIGHT AND LOW CHANCE POPS FOR SHOWERS SATURDAY AFTERNOON...AND ALSO KEEP THE THUNDER MENTION ACROSS EXTREME SOUTHWEST NEBRASKA AS MID LEVEL LAPSE RATES START TO STEEPEN IN THAT AREA. GULF MOISTURE STREAMS NORTH INTO THE AREA DURING THE AFTERNOON...AND AN INCREASE IN LOW STATUS CLOUDS FROM THE SOUTH IS EXPECTED. LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) FORECAST CHALLENGE CONTINUES TO BY SNOWFALL ACCUMULATIONS WITH THE APPROACHING WINTER STORM SATURDAY NIGHT INTO SUNDAY. LIKE YESTERDAY...ALBEIT...TO A SLIGHTLY LESSER DEGREE...THE MODEL SOLUTIONS CONTINUE TO BE DIVERGENT IN THE TIMING AND TRACK OF THE H5 LOW...AND SURFACE LOW WITH THE APPG WINTER SYSTEM. THE NAM CONTINUES TO BE THE FASTEST AND FURTHEST NORTH OF THE FORECASTS...THE ECMWF IS THE FURTHEST SOUTH AND THE GFS IS A COMPROMISE IN THE MIDDLE. THE CANADIAN AND UKMET SHOW SOME LIMITED SUPPORT FOR A GFS/ECMWF COMPROMISE AND THIS WAS UTILIZED THIS MORNING. AS IT STANDS ATTM...THE HEAVIEST ACCUMULATIONS CONTINUE TO BE ALONG AND NORTH OF A LINE FROM OGALLALA...STAPLETON...TO O`NEILL...WHERE THE STRONGEST DEFORMATION AND MID LEVEL FRONTOGENESIS SETS UP. SOUTH OF THIS LINE...WEAKER MID LEVEL LIFT...WILL LIMIT ACCUMS TO 2 TO 5 INCHES. ONE WORD OF CAUTION HERE...ALL OF THESE MODEL SOLUTIONS HAVE BEEN PERSISTENT WITH THEIR STORM TRACKS OVER THE PAST COUPLE OF DAYS. IF SYSTEM DOES TRACK FURTHER SOUTH AS ADVERTISED IN THE ECMWF...SNOW ACCUMULATIONS WILL BE HEAVIER ALONG THE INTERSTATE CORRIDOR AND SLIGHTLY LIGHTER ALONG THE SD/NEBR BORDER. HIGHER FORECAST CONFIDENCE LIES WITH EXPECTED WINDS ON THE BACK SIDE OF THE EXITING SYSTEM SUNDAY. SURFACE LOW PRESSURE DROPS TO AROUND 990 MB...WITH A VERY TIGHT SURFACE GRADIENT ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. SUSTAINED WINDS OF 25 TO 35 MPH...WITH GUSTS TO 50 MPH LOOK PROBABLE...AND WITH ANY ACCUMULATED SNOW...WILL LEAD TO CONSIDERABLE BLOWING AND DRIFTING SNOW. DECIDED TO UPGRADE THE WINTER STORM WATCH TO A BLIZZARD WATCH EARLIER...GIVEN THE EXPECTED WINDS LATE SATURDAY NIGHT AND SUNDAY EVENING. PLACED THE REMAINDER OF THE FORECAST AREA MINUS CHASE...HAYES AND FRONTIER COUNTIES IN A WINTER STORM WATCH...TO ACCOUNT FOR WINDS...EVEN THOUGH EXPECTED ACCUMS ARE ON THE ORDER OF 2 TO 5 INCHES. AS MENTIONED ABOVE...WILL UTILIZE WATCH HEADLINES FOR NOW...AS THE LOCATION OF THE HEAVIEST SNOW...IS STILL NOT DEFINED JUST YET. IN ADVANCE OF THE SYSTEM...STRONG SOUTHERLY WINDS WILL CONTINUE INTO SATURDAY AFTERNOON...ALLOWING LOW LEVEL MOISTURE TO PUSH INTO SOUTHWESTERN AND CENTRAL NEBRASKA. MID LEVEL LAPSE RATES WILL STEEPEN SATURDAY AFTERNOON AND EVENING...LEADING TO DECENT MID LEVEL INSTABILITY ACROSS SOUTHWESTERN AND CENTRAL NEBRASKA. AS THE UPPER LEVEL LOW PUSHES INTO NWRN KS SATURDAY EVENING...LEAD SHOWERS AND EVEN AN EMBEDDED THUNDERSTORM WILL BE POSSIBLE. AT THIS TIME...NO SEVERE THUNDERSTORMS ARE EXPECTED...HOWEVER...I WOULDN`T BE SURPRISED IF SOME GRAUPEL OR PEA SIZED HAIL OCCURS...GIVEN THE LOW FREEZING LEVELS. ALSO...SOME MID LEVEL INSTABILITY EXTENDS NORTH INTO NORTH CENTRAL NEBRASKA SATURDAY NIGHT...WHICH MAY FACILITATE POSSIBLE THUNDER SNOW. EXTENDED RANGE CONTINUES WITH A BROAD LONGWAVE TROUGH FIRMLY IN PLACE OVER THE EASTERN TWO-THIRDS OF THE CONUS...WITH NORTHWEST FLOW OVER THE FORECAST AREA. THIS WILL HELP LIMIT TEMPERATURES TO NEAR OR JUST BELOW NORMAL. ONLY PRECIP CONCERN COMES WEDNESDAY NIGHT AND THURSDAY AS A SHORTWAVE EMBEDDED IN THE NORTHWEST FLOW DIVES SOUTHEAST OUT OF CANADA. THIS WILL BRING A SLIGHT CHANCE OF LIGHT SNOW TO THE NORTHERN HALF OF THE CWA AND ALSO BRING ANOTHER SHOT OF COOLER TEMPS TO THE AREA TO END THE WEEK. AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) FR CONDITIONS SHOULD PREVAIL ACROSS WESTERN AND NORTH CENTRAL NEBRASKA FOR THE NEXT 24 HRS. OTHERWISE AN INCREASE IN HIGH CIRRUS CLOUDS CAN BE EXPECTED...ALONG WITH GUSTY SOUTH SFC WINDS TO 30 KTS TODAY. WINDS WILL DIMINISH SOME TONIGHT...GENERALLY SOUTH TO SOUTHEAST 10 TO 15 KTS. && .LBF WATCHES/WARNINGS/ADVISORIES...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING FOR NEZ028-029-038-058-059. BLIZZARD WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING FOR NEZ004>010-022>027-035>037-056-057-094. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION....CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
108 AM EST SAT FEB 9 2013 .SYNOPSIS... A MAJOR STORM MOVING UP THE EAST COAST WILL BRING MODERATE TO HEAVY SNOW TO THE AREA TONIGHT. THE STORM WILL MOVE OFF TO THE NORTHEAST SATURDAY FOLLOWED BY CLEARING AND COLD WEATHER SATURDAY AND SATURDAY NIGHT. MILDER WEATHER WILL RETURN ON SUNDAY... THEN THE NEXT STORM SYSTEM COULD BRING A MIX OF PRECIPITATION ON MONDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1015 PM UPDATE... UL LOW STILL SPINNING ACRS WRN NY AND EAST COAST UL WV NRNG CAPE COD ATTM. SNOW IS DCRSG WEST OF THE I-81 CORRIDOR THO BANDS CONTINUE TO DVLP AT RANDOM AND PRODUCE 1 TO 1.5 INCHES/HR THUS NO CHGS WL BE MADE TO WSW HEADLINES AT THIS TIME EXCEPT FOR A REFRESH OF WRDG. LATEST RAP UPGLIDE IN THE 285K LAYER INDICATES SNOW WL CONTINUE ALONG THE I-81 CORRIDOR FOR THE NEXT HR BFR BCMG SIGNIFICANTLY LIGHTER. SNOW IS BCMG MODERATE TO HVY AT TIMES ACRS THE ERN CNTYS AS MOISTURE IS INCRSG AND BEING LIFTED BTWN TWO SEPARATE STORMS. DUAL-POL INDICATING 2-3 INCHES PER HOUR IN OTSEGO/DELAWARE/WAYNE CNTYS AND EXPECT THIS TO TRANSLATE SLOWLY OFF TO THE EAST. A LITTLE CONCERNING AS THESE WERE THE LAST CNTYS TO SEE SNOWFALL TONIGHT BUT THEY WILL BE MAKING UP FOR IT IN A BIG WAY THRU MRNG. ONLY MINOR TWEAKS TO STORM TOTALS, CLOSER TO 7 INCHES AREA-WIDE WITH ERN ZONES EXPECTING 6-9 INCHES. OTHER THAN THESE CHGS HV JUST TWEAKED HRLY T/TD VALUES. 630 PM UPDATE... SFC LOW CONTS TO DROP AND IS NOW DOWN TO 985MB SOUTH OF CAPE COD. THE MAIN WX STORY FOR US CONTS TO BE UL TROF DIVING THRU WRN NY WITH ECHOES RAPIDLY INTENSIFYING ACRS WRN STEUBEN CNTY. MODERATE- OCNLY HVY SNOW IS NOW LOCATED ALG THE I-81 CORRIDOR AND AS UL TROF DIVES SOUTHEAST THRU CNTRL PA THIS BAND WL LKLY PIVOT AND CONT TO BRING SNOW TO THE AREA THRU LATE EVNG AND POSSIBLY EVEN THRU MIDNIGHT. MOST INTENSE RATES ARE UP TO 2 INCHES PER HR AND WIDESPREAD 1 TO 1.5 INCH/HR AMNTS PER DUAL-POL RADAR ESTIMATES. LATEST RAP AND HIRES NMM MODELS INDICATE SOME FORM OF BANDING TO PERSIST ALONG I-81 CORRIDOR THRU 02Z AND ERN THIRD OF CWA THRU 06Z. THIS WL ALLOW SNOWFALL AMNTS TO APPRCH WRNG CRITERIA. AS THE SNOW CONTS TO FALL, TEMPS ALOFT WL COOL THIS EVNG WITH FLAKES BCMG BIGGER, WHEREAS FINE SNOW OCCURRED THIS AFTN. THIS WL LKLY RESULT IN WIDESPREAD 6-8 INCH AMNTS TONIGHT WITH SNOW TOPPING 10 INCHES ACRS EXTRM ERN CNTYS. 330 PM UPDATE... SURFACE LOW PRESSURE OFF THE EAST COAST IS DOWN TO 992 MB EAST OF DELMARVA. HOWEVER THE KEY FEATURE TO NOTE FOR OUR AREA IS A STRONG UPPER LEVEL WAVE TRACKING SOUTHEAST FROM THE EASTERN GREAT LAKES. THE TRACK OF THIS SYSTEM WILL BE CRITICAL FOR SNOW AMOUNTS IN OUR AREA TONIGHT. THE MID-LEVEL CENTER IS CURRENTLY OVER LAKE ERIE... AND A DRY SLOT HAS PUSHED EAST AROUND THE SOUTH SIDE OF THIS SYSTEM SHUTTING PRECIPITATION OFF OVER WESTERN PENNSYLVANIA. THIS DRY SLOT IS PROGRESSING STEADILY EAST ACROSS CENTRAL PA LATE THIS AFTERNOON. HOWEVER... THE TRACK OF THIS UPPER SYSTEM IS EXPECTED TO BE SOUTHEASTWARD ACROSS CENTRAL PA THIS EVENING... WHICH SHOULD SHUNT THE DRY SLOT OFF THE SOUTH OF OUR AREA. EXPECT THE DRY SLOT TO GET ABOUT HALF WAY ACROSS THE TWIN TIERS EARLY THIS EVENING... THEN STOP AND POSSIBLY EVEN BUILD BACK TO THE WEST AS THE ENTIRE STORM PIVOTS AND MOISTURE BEGINS TO WORK BACK IN FROM THE EAST AROUND THE NORTH SIDE OF THE UPPER LOW. AS A RESULT... MODERATE TO AT TIMES HEAVY SNOW IS LIKELY TO PERSIST... AT LEAST ACROSS THE EASTERN 2/3 OF OUR FORECAST AREA... UNTIL AFTER MIDNIGHT. THIS WILL ALLOW WARNING CRITERIA SNOWS TO ACCUMULATE IN MOST AREAS. AT THIS TIME THIS SCENARIO IS SUPPORTED BY ALL OF OUR SHORT RANGE GUIDANCE... AS WELL AS RADAR AND SATELLITE LOOPS WHICH SHOW THE ENTIRE SYSTEM PIVOTING AS IT TAKES ON AN INCREASINGLY NEGATIVE TILT AND RADAR RETURNS EXPAND. INTENSITY OF THE SNOW WILL BE INTERESTING THIS EVENING. WE HAVE ALREADY GOTTEN A REPORT OF 3.7 INCHES IN 90 MINUTES OVER WAYNE COUNTY NY JUST SOUTH OF LAKE ONTARIO. SEVERAL OTHER SPOTTER REPORTS INDICATE THAT HEAVY SNOW IS DEVELOPING IN NORTH-SOUTH ORIENTED BANDS OVER THE WESTERN HALF OF OUR FORECAST AREA. NAM CROSS-SECTIONS AND PLAN VIEW CHARTS SHOW A PRONOUNCED NORTH-SOUTH BAND OF FRONTOGENESIS DEVELOPING IN THE 850-700 MB LAYER NEAR THE I-81 CORRIDOR THROUGH 00Z... WITH A LAYER OF NEGATIVE EPV (REDUCED STABILITY) ABOVE THE FRONTOGENESIS. THE FRONTOGENESIS PERSISTS ACROSS OUR CENTRAL COUNTIES THROUGH 03Z BEFORE MOVING EAST. THIS PATTERN IMPLIES THE POTENTIAL FOR SOME HEAVY BANDS OF SNOW PERSISTING THROUGH ABOUT 06Z WITH SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR POSSIBLE. SNOW WILL PULL EAST OF THE AREA AFTER 06Z. WILL HAVE TO WATCH FOR SOME SNOW BANDS DEVELOPING AND PERSISTING SOUTH OF THE FINGER LAKES AFTER 09Z WITH A FEW INCHES OF EXTRA SNOW POSSIBLE IN TIOGA/TOMPKINS COUNTIES. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/... 230 PM UPDATE... MAJOR WINTER STORM WILL CONTINUE TO PULL AWAY FROM OUR AREA ON SAT. HOWEVER...IN THE AM HRS...SOME MULTI-BAND/FINGER LKS LES BANDS ARE LIKELY...AS LONG AS THE DEEPER SYNOPTIC MOISTURE LINGERS...WITH LOW-LVL CAA...AND A 320-340 FLOW. WE`VE ADDED THE POTENTIAL FOR LOCALIZED 1-2" SNOWS THIS PD...SPCLY DOWNWIND FROM CAYUGA LAKE. DURG THE AFTN (STARTING 15-18Z)...SIG DRYING IS PROGGED...WITH SKIES EXPECTED TO CLEAR OUT AREA-WIDE. WINDS WILL BE GUSTY ON SAT...OWING TO A TIGHT PRES GRADIENT BETWEEN THE INTENSE STORM OFF THE NEW ENG COAST...AND HIGH PRESSURE TO OUR W. SAT NGT LOOKS QUITE COLD FROM THIS VANTAGE PT...WITH MAINLY CLEAR SKIES...FAIRLY FRESH SNOW COVER...AND THE COLDEST AIR COMING IN AT THAT TIME. WE EXPECT OUR NORMALLY COLDER RURAL VLYS TO DROP BELOW ZERO. SUN LOOKS QUIET...WITH SUNSHINE FADING BEHIND INCREASING CLDS IN THE AFTN. A FAST MOVING UPR WV AND SFC FRNT ARE STILL EXPECTED TO CROSS NY/PA EARLY MON...WITH A QUICK SHOT OF PCPN BETWEEN MAINLY 09Z AND 15Z. PTYP CONTS TO BE A CONCERN...AS A WARM LYR CLEARLY PRESENTS ITSELF IN THE 900-850 MB LYR. AT THE SAME TIME...SFC TEMPS WILL BE COLD...AND THUS A PD OF -FZRA IS LIKELY. THIS MENTION WILL STILL BE MADE IN THE HWO. MON AFTN...AS TEMPS WARM AND PCPN TAPERS OFF...WE SHOULD BE LEFT WITH SCTD -SHRA/SPRINKLES...FOR THE MOST PART. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... 1 PM UPDATE... FOLLOWED HPC GUIDANCE. MODELS SIMILAR. MULTIPLE WEAK SYSTEMS GOING THROUGH. COLD ENOUGH FOR MOSTLY SNOW BUT SFC TEMPERATURES SLIGHTLY ABOVE NORMAL. TEMPERATURES NOT COLD ENOUGH FOR DECENT LAKE EFFECT SNOW. MONDAY NIGHT THE FIRST SYSTEM WITH A MIX CHANGING TO SNOW. A SECONDARY COLD FRONT GOES THROUGH TUESDAY. WEDNESDAY SOME DIFFERENCES WITH THE GFS GETTING INTO PA WITH SNOW WHILE THE EURO KEEPS THE SNOW SOUTHEAST WITH A COASTAL STORM. HIGH PRESSURE THURSDAY THEN ANOTHER STORM FRIDAY TO SATURDAY. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... MAIN SYNOPTIC SNOW WINDING DOWN ATTM BUT STILL SOME IFR/MVFR CIGS AND VSBYS IN LGT SNOW AND BLSN. XPCT LTL CHG OVRNGT OTR THAN A SLOW IMPRVMT. GUSTY WINDS WILL CONT TO DVLP ALL STATIONS AS THE LOW DEEPENS OFF THE NEW ENG CST. ON SAT...NW FLOW WILL DVLP SOME LE SNOW THRU ABT MIDDAY WITH MVFR CIGS AND VSBY PSBL. LTR IN THE DAY AND THRU THE END OF THE PD...VERY DRY AIR AND A LWRG INV SHD BRING VFR SKIES AND VSBYS. .OUTLOOK... SUN...VFR. SUN NGT/MON...MVFR/IFR POSSIBLE IN A WINTRY MIX /INCLUDING FREEZING RAIN/...CHANGING TO ALL RAIN ON MON. MON NGT TO TUE NGT...SCT MVFR CNTRL NY IN -SHSN...VFR ELSEWHERE. WED...IMPROVE TO VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR PAZ038>040-043-044-047-048-072. NY...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...MSE NEAR TERM...MSE/PVN SHORT TERM...MLJ LONG TERM...TAC AVIATION...DGM/DJP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1003 PM EST SUN FEB 10 2013 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH ACROSS THE AREA OVERNIGHT. RAIN IS EXPECTED TONIGHT INTO MONDAY AHEAD OF A PRE-FRONTAL TROUGH. A COLD FRONT WILL MOVE ACROSS THE AREA EARLY ON TUESDAY...BEFORE STALLING. A DEEPENING LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA ON WEDNESDAY...WITH HIGH PRESSURE RETURNING FOR THE END OF THE WEEK. AN ARCTIC BLAST MAY REACH THE EASTERN CAROLINAS IN THE WAKE OF A COLD FRONT NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 930 PM SUNDAY...THE FORECAST REMAINS ESSENTIALLY ON-TRACK THIS EVENING. REGIONAL RADAR COMPOSITES SHOW ECHOES NOT QUITE TO I-95...AND SURFACE OBS SHOW PRECIP IS REACHING THE GROUND UNDER ALL BUT THE 15 DBZ AND LOWER RADAR REFLECTIVITIES. THE LATEST SEVERAL RUNS OF THE RUC AND HRRR MODELS SUGGEST A LIGHTER-QPF EVENT THAN WAS INITIALLY THOUGHT...AND WITH A SOUTHWARD SHIFT IN THE LOCATION OF HEAVIEST RAINFALL IN THE 3-6 A.M. TIME FRAME. SINCE THIS IDEA APPEARS TO BE SUPPORTED BY LIGHT RADAR ECHOES OBSERVED AS FAR SOUTH AS AUGUSTA GA...I HAVE INCREASED POPS FOR THE SOUTHERN END OF THE SC PEE DEE REGION AND DOWN TO THE COAST BY 10-20 PERCENT...ALTHOUGH WITH NO ATTENDANT INCREASE IN FORECAST RAINFALL AMOUNTS. THE SYNOPTIC PATTERN HAS A WARM FRONT EXTENDING FROM JUST SOUTH OF CAPE LOOKOUT TO NEAR CAROLINA BEACH...THEN SOUTH-SOUTHWESTWARD JUST OFFSHORE FROM MYRTLE BEACH AND GEORGETOWN. IN RESPONSE TO STRENGTHENING SOUTH FLOW THE FRONT IS LIFTING NORTHWARD AT AN INCREASING RATE AND MAY "JUMP" NORTH THROUGH MY ENTIRE FORECAST AREA IN THE NEXT COUPLE OF HOURS. EASTERLY SURFACE WINDS WILL VEER SOUTHERLY AND INCREASE TO 10-15 MPH...WITH 20-25 MPH GUSTS POSSIBLE AFTER MIDNIGHT. A HEALTHY UPPER TROUGH EXTENDS SOUTHWARD FROM AN UPPER LOW IN SOUTHERN MINNESOTA. PLENTY OF GULF MOISTURE ADVECTED NORTH AHEAD OF THIS TROUGH IS PRODUCING SEVERE WEATHER AND HEAVY RAINFALL ACROSS THE DEEP SOUTH. ALTHOUGH THE AIRMASS OVER THE EASTERN CAROLINAS SHOULD REMAIN TOO STABLE FOR CONVECTION...THIS SAME MOISTURE FEED IS WHAT WILL CREATE OUR RAINFALL CHANCES TONIGHT. BY DAYBREAK RAINFALL AMOUNTS AROUND A HALF INCH ARE EXPECTED ACROSS DARLINGTON COUNTY... TAPERING DOWN TO AROUND A THIRD OF AN INCH FROM LUMBERTON INTO MARION AND FLORENCE. CLOSER TO THE COAST AND SOUTH TOWARD THE SANTEE RIVER RAINFALL AMOUNTS OF ONE OR TWO-TENTHS OF AN INCH ARE EXPECTED BY DAYBREAK. WE ARE AT OUR LOW TEMPERATURES CURRENTLY...AND READINGS SHOULD RISE BY 3-5 DEGREES OVER THE NEXT SEVERAL HOURS AS WARMER AIR FROM GEORGIA AND OFFSHORE SOUTH CAROLINA ADVECTS OVERHEAD. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...COMPLICATED AND CHALLENGING FORECAST PERIOD. FORECAST AREA WILL BE IN THE WARM SECTOR AHEAD OF PRE-FRONTAL TROUGH ON MON. EVEN WITH AN ABUNDANCE OF CLOUD COVER...CAPE VALUES MAY STILL REACH UP TO 500 J/KG MON AFTERNOON. DEEP MOISTURE WILL BE IN PLACE...WITH PRECIPITABLE WATER VALUES NEAR 1.5 INCHES. THE HIGHEST INSTABILITY WILL BE ACROSS THE SOUTHERN AND EASTERN ZONES...THUS ADDED ISOLATED THUNDERSTORMS TO THE FORECAST FOR MON AFTERNOON. GIVEN THE MAGNITUDE OF LIFT...HIGHLY CONFIDENT THERE WILL BE SHOWERS AND WILL CARRY CATEGORICAL POPS MON. AS THE PRESSURE GRADIENT TIGHTENS ON MON...SW LOW LEVEL JET WILL INCREASE TO 40 TO 50 KT AND EXPECT SOME WIND GUSTS ON MON TO AROUND 30 MPH. ONCE THE PRE-FRONTAL TROUGH MOVES THROUGH MON AFTERNOON/EARLY EVE...LASTLY ALONG THE COAST...DRIER AIR IN THE LOW AND MID LEVELS WILL WORK INTO THE FORECAST AREA. THIS DRIER AIR SHOULD LARGELY CUT OFF THE RISK FOR PRECIPITATION...BUT GIVEN THE ACTUAL FRONT WILL NOT LIMP INTO THE FORECAST AREA TIL TUE MORNING...WILL CARRY SMALL POPS FOR PORTIONS OF THE AREA EVEN AFTER DARK MON. ATTENTION THEN TURNS TO A SOUTHERN STREAM SYSTEM WHICH WILL BE DEVELOPING ALONG THE GULF COAST IN RESPONSE TO A HIGHLY ENERGIZED MID-LEVEL SHORTWAVE MOVING ACROSS THE SOUTHERN PLAINS TUE. THE EUROPEAN MODEL HAS BEEN THE MOST CONSISTENT AND CONTINUES TO INDICATE SURFACE LOW PRESSURE MOVING ALONG A STALLED FRONT AND REACHING THE SE STATES TUE NIGHT...BEFORE TRANSFERRING TO THE CAROLINA COAST DURING WED. STILL SOME DISCREPANCY AS TO HOW FAR N THE STRONGEST ISENTROPIC UPGLIDE WILL DEVELOP AND THUS WHERE THE HEAVIEST RAIN WILL DEVELOP. CONFIDENT THAT POPS...WHICH HAD BEEN TRENDED LOWER MON NIGHT INTO TUE...WILL BEGIN TO REVERSE HIGHER... FROM S TO N...TUE AFTERNOON AND ESPECIALLY TUE NIGHT. WILL BRING POPS BACK TO CATEGORICAL OVERNIGHT TUE INTO WED MORNING. THE CHARACTER OF PRECIPITATION THIS TIME AROUND SHOULD BE STRATIFORM AS LONG AS THE MORE SOUTHERN TRACK VERIFIES AND WILL NOT ADD THUNDERSTORMS TO THE TUE FORECAST AT THIS TIME. CONFIDENCE IN THE QPF FORECAST HAS NOT INCREASED...BUT AT THIS TIME WE ARE FORECASTING A 1 TO POSSIBLY 3 INCH RAINFALL EVENT THROUGH MID WEEK. THIS AMOUNT OF RAIN SHOULD NOT BE ENOUGH TO CAUSE FLOODING ALTHOUGH RIVERS WILL LIKELY BE ON THE RISE MID AND LATE WEEK. SHOULD SIGNIFICANTLY HIGHER RAINFALL AMOUNTS MATERIALIZE...THE RISK FOR SOME FLOODING WOULD INCREASE. LATER FORECASTS WILL STRIVE TO BETTER DEFINE THE TOTAL AMOUNT OF RAINFALL AND ANY FLOOD RISK. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...MAIN FOCUS WILL BE ON THE EARLY PART OF THE FORECAST WHERE POPS REMAIN A DILEMMA AND THE END OF THE PERIOD WHERE ARCTIC AIR WILL BE AN ISSUE. FOR WEDNESDAY...THERE REMAINS A DIFFERENCE IN MEDIUM RANGE GUIDANCE AS THE ECMWF IS LESS AMPLIFIED AND HENCE MORE PROGRESSIVE WITH THE MAIN UPPER LEVEL FEATURE MOVING ACROSS THE TENNESSEE VALLEY. THE GFS REMAINS CONSISTENT WITH A SLOWER AND DEEPER SOLUTION. I HAVE MAINTAINED THE INHERITED CATEGORICAL POPS BASED PRIMARILY ON CONTINUITY OF THE GFS ALTHOUGH IT SHOULD BE NOTED CONFIDENCE EVEN JUST A FEW DAYS OUT REMAINS UNUSUALLY LOW. FOR THURSDAY THROUGH SATURDAY...A BROAD EASTERN U.S. TROUGH DEVELOPS WITH SURFACE HIGH PRESSURE CENTERED ACROSS THE SOUTHERN U.S. EXPECT TEMPERATURES AT OR JUST BELOW CLIMATOLOGY ALONG WITH DRY CONDITIONS. AS THE EASTERN PACIFIC RIDGE DEVELOPS THROUGH THE PERIOD... SEVERAL SHORTWAVES WILL DIVE SOUTH AND REINFORCE THE BROAD TROUGH THUS RELEASING A SHOT OF ARCTIC AIR. THE 0600 OPERATIONAL GFS WAS ADVERTISING 850MB TEMPERATURES AS COLD AS MINUS 15 DEGREES C MOVING ACROSS THE AREA BRIEFLY NEXT SUNDAY. HOWEVER THE 1200 UTC GUIDANCE HAS MODERATED SOMEWHAT AND THESE NUMBERS APPEAR MORE REASONABLE. ACTUAL LOWS WILL BE MODULATED BY DECOUPLING OR LACK THEREOF. IT HAS ALSO BEEN MY EXPERIENCE IN THE PAST THAT ARCTIC AIR OUTBREAKS LATER IN THE SEASON WITH THE HIGHER SUN ANGLES MAKE MEX NUMBERS MORE ACCURATE. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 00Z...CURRENTLY VFR AT ALL TERMINALS. A LARGE AREA OF RAIN WILL MOVE ACROSS THE TERMINALS BEGINNING THIS EVENING AT KFLO/KLBT. CONFIDENCE IS HIGH FLIGHT CONDITIONS WILL DETERIORATE TO MVFR DUE TO MAINLY REDUCED VSBYS IN RAIN AND BR AROUND 05Z AT KFLO/KLBT. MVFR CIGS APPEAR TO BE MORE LIKELY AT THE KFLO TERMINAL WHERE GREATER LIFT IS INDICATED. AT KLBT SIGNIFICANT SUBSIDENCE IS INDICATED AND CIGS COULD VERY WELL BE MORE OF A TEMPO NATURE. THE HEAVIEST OF RAIN SHOULD OCCUR 07Z-14Z. IT IS DURING THIS TIME THE GREATEST THREAT IF IFR WILL OCCUR. MOST OF THE RAIN SHOULD END BY 12Z BUT THERE WILL REMAIN A GOOD CHANCE OF MVFR/SHOWERS THROUGH 17Z. THERE IS HIGH CONFIDENCE OF TEMPO MVFR CIGS AT THE COASTAL TERMINALS 03-07Z. MVFR VSBYS/CIGS WILL BECOME PREDOMINANT AS THE AREA OF RAIN MOVES IN BY 07Z. THE HEAVIEST OF RAIN SHOULD OCCUR IN THE 10Z-14Z TIME FRAME. IT IS DURING THIS TIME THE GREATEST THREAT IF IFR WILL OCCUR. THERE MAY BE A TEMPO LULL IN PRECIP 15-18Z BUT THERE WILL REMAIN A GOOD CHANCE OF TEMPO IFR/SHOWERS THROUGH 21-00Z. EXTENDED OUTLOOK...RAIN LIKELY WITH PERIODS OF MVFR/IFR CONDITIONS THROUGH WEDNESDAY. VFR DEVELOPING THURSDAY AND PERSISTING THROUGH FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM SUNDAY...THE WARM FRONT IS FINALLY BEGINNING TO MAKE A MOVE TO THE NORTH...CURRENTLY EXTENDING FROM JUST SOUTH OF CAPE LOOKOUT TO NEAR CAROLINA BEACH...THEN SOUTH-SOUTHWESTWARD THROUGH THE SOUTH CAROLINA COASTAL WATERS REMAINING JUST EAST OF GEORGETOWN. ON THE COOL SIDE OF THIS BOUNDARY SURFACE WINDS REMAIN EASTERLY. THE SOUTHERLY WINDS OVER THE FRONT ARE ERODING THE COOLER SURFACE AIR RATHER QUICKLY...AND THE FRONT SHOULD "JUMP" NORTH ACROSS MY FORECAST AREA IN THE NEXT SEVERAL HOURS...WITH SOUTHERLY WINDS AT THE SURFACE THE ANTICIPATED RESULT. WIND SPEEDS SHOULD INCREASE TO 20-25 KT...BUT WITHOUT ANY SUBSTANTIAL GUSTINESS GIVEN VERY STABLE THERMODYNAMIC PROFILES. SEAS CURRENTLY 3-4 FT WILL BEGIN TO BUILD SUBSTANTIALLY AFTER MIDNIGHT AND COULD REACH 8 FEET ACROSS THE OUTER PORTION OF THE COASTAL WATERS BY DAYBREAK MONDAY. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...A MOIST AND INCREASING SOUTHERLY FLOW WILL DEVELOP AHEAD OF A PRE-FRONTAL TROUGH. SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO HAVE ALREADY BEGUN BY THE START OF THE PERIOD AND TO CONTINUE INTO MON NIGHT...SSW TO SW WINDS TO 20 TO 25 KT WITH SEAS PEAKING IN THE 6 TO 10 FT RANGE...HIGHEST ACROSS THE OUTER NORTHERN WATERS. DECREASING WINDS WILL VEER TO W BEHIND THE PRE-FRONTAL TROUGH MON EVE AND THEN BECOME NW BEHIND A COLD FRONT TUE MORNING. WINDS AND SEAS ARE EXPECTED TO FALL BELOW ADVISORY CRITERIA LATE MON NIGHT. SINCE DEWPOINTS WILL BE CLIMBING INTO THE LOWER 60S...THERE IS SOME RISK FOR THE DEVELOPMENT OF SEA FOG ON MON. AT THIS TIME...GIVEN THE MAGNITUDE OF WIND...WILL OPT FOR STRATUS OVER FOG AND WILL LEAVE OUT OF THE FORECAST. AS LOW PRESSURE APPROACHES FROM THE W AND SW TUE NIGHT...WINDS WILL SHIFT TO THE NE AND THEN ENE...INCREASING WITH THE APPROACH OF DAYBREAK WED. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...CHANGEABLE CONDITIONS AT LEAST THROUGH THE EARLY PART OF THE PERIOD...WILL BE THE HIGHLIGHT OF THE FORECAST. EASTERLY FLOW INITIALLY WILL QUICKLY GIVE WAY TO A SOUTHERLY FLOW BY MIDDAY WEDNESDAY AS A WARM FRONT MOVES ACROSS TO THE NORTH. WINDS THEN QUICKLY VEER TO WEST NORTHWEST BY EARLY THURSDAY AS A COLD FRONT MOVES ACROSS. BY FRIDAY WINDS ESSENTIALLY BECOME LIGHT AND VARIABLE AS HIGH PRESSURE DRIFTS OVERHEAD. FOR SEAS...SOME RESIDUAL SIX FOOTERS MAY WARRANT AN ADVISORY FOR PART OR MOST OF WEDNESDAY ESPECIALLY ACROSS THE OUTER WATERS BUT LATER THURSDAY AND FRIDAY OFFER MORE BENIGN VALUES WITH THE DIMINISHING OFFSHORE FLOW. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 AM EST TUESDAY FOR AMZ250-252-254-256. && $$ NEAR TERM...JDW/TRA SHORT TERM...RJD LONG TERM...SHK AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 PM EST SAT FEB 9 2013 .SYNOPSIS... HIGH PRESSURE WILL SETTLE OVER THE EAST COAST TONIGHT THROUGH SUNDAY MORNING... BEFORE SHIFTING OFFSHORE SUNDAY AFTERNOON. A STORM SYSTEM WILL APPROACH FROM THE WEST LATE SUNDAY AND SWEEP THROUGH THE AREA SUNDAY NIGHT AND MONDAY. YET ANOTHER SYSTEM WILL AFFECT THE REGION TUESDAY NIGHT AND WEDNESDAY. && .NEAR TERM /THROUGH SUNDAY/... AS OF 920 AM SATURDAY... THROUGH TODAY: LOTS OF SUN TODAY WITH AREA AND UPSTREAM RADIOSONDE DATA SHOWING VERY DRY AIR THROUGH THE COLUMN AND FAST CONFLUENT NW FLOW ALOFT WITH STRONG DEEP SUBSIDENCE TAKING PLACE. SOUNDING DATA ALSO SHOWS 20-30 KTS OF WIND THIS MORNING THROUGH THE SHALLOW MIXED LAYER JUST OFF THE SURFACE... ALTHOUGH THIS WILL BE DIMINISHING AS THE DAY GOES ON AS THE 925 MB ANTICYCLONE AND SURFACE RIDGE CENTER OVER THE LOWER GREAT LAKES BUILDS SOUTHEAST WITH A NEW CENTER FORMING OVER THE WRN CAROLINAS LATER TODAY. WILL RETAIN BREEZY CONDITIONS AND OCCASIONAL GUSTS MAINLY IN THE EAST UNTIL EARLY AFTERNOON. THE DRY-ADIABATIC THERMAL PROFILE FROM THE RAP MODEL OUTPUT SUPPORTS HIGHS OF 50 TO 59 (NE TO SW). -GIH TONIGHT: SURFACE HIGH PRESSURE WILL SETTLE OVER THE REGION TONIGHT... WITH RIDING ALOFT OVERHEAD. HOWEVER... WE WILL BEGIN TO SEE SOME HIGH CLOUD FILTER INTO THE REGION FROM THE NEXT S/W TROUGH AND ASSOCIATED COLD FRONT APPROACHING THE AREA FROM THE CENTRAL U.S. THIS MAY IMPACT OVERNIGHT LOW TEMPS A BIT... MOST ACROSS THE WEST. THUS... WILL SHOW LOW TEMPS RANGING FROM THE MID TO LOWER 20S EAST AND USUAL RURAL COLD OUTLYING AREAS (EXCEPT FOR THE FAR WESTERN PORTIONS OF THE CWA) TO THE UPPER 20 TO NEAR 30 IN THE FAR WEST AND URBAN AREAS. SUNDAY: MAINLY MID AND HIGH LEVEL CLOUD COVER WILL BE ON THE INCREASE ACROSS THE AREA ON SUNDAY... AS BOTH THE SURFACE HIGH AND RIDGING ALOFT SLIDE TO THE EAST OF THE AREA. EXPECT ANY RAIN TO REMAIN TO THE WEST OF THE AREA THROUGH EARLY SUNDAY EVENING AS BOTH THE NAM AND GFS BUFR SOUNDINGS SHOW A GOOD DEAL OF DRY AIR BELOW 600 MB ACROSS CENTRAL NC. GIVEN THE INCREASING CLOUD COVER AND ONLY ON AVERAGE OF 5 TO 10 METER INCREASE IN LOW LEVEL THICKNESS VALUES WILL KEEP TEMPS ON THE COOL SIDE OF GUIDANCE AND GO WITH HIGHS RANGING FROM 53 NORTH TO 59 SOUTH... NEAR NORMAL FOR THIS TIME OF YEAR. && .SHORT TERM /MONDAY THROUGH TUESDAY/... AS OF 235 PM SATURDAY... ONGOING PRECIPITATION MONDAY MORNING ASSOCIATED WITH DISTURBED SOUTHWESTERLY FLOW ALOFT AND WARM ADVECTION/ISENTROPIC LIFT WILL SHIFT EAST BY MIDDAY AS THE COR OF THE LLJ MOVES OFFSHORE. THE MODEL CONSENSUS WOULD HAVE PRECIP COMPLETELY OUT OF THE EASTERN CWA BY MID AFTERNOON WITH INCREASINGLY WESTERLY DEEP LAYER FLOW. TEMPS ARE THE BIGGER FORECAST STRUGGLE...AS EARLY MORNING PRECIP FALLING INTO THE DRY AIRMASS DEPOSITED BY A 1030MB SHIFTING OFFSHORE MONDAY MORNING WOULD SUPPORT THE POTENTIAL FOR A WEAK IN-SITU WEDGE AIRMASS. THE HIGH IS NOT IN A FAVORABLE LOCATION TO SUPPORT THIS AND MODELS WANT TO MIX THE WARM SECTOR THROUGH THE AREA RATHER QUICKLY MONDAY MORNING....EVIDENCE BY THE LATEST MAV MOS FORECASTING LOW TO MID 70S. HOWEVER...THIS IS OFTEN A DEFICIENCY IN THE MODELS AND LOWERS CONFIDENCE IN THE CURRENT FORECAST. WILL CONTINUE TO ERR ON ON THE COOL SIDE...MORE INLINE WITH MET MOS. THE COLD FRONT WILL SWEEP ACROSS THE AREA MONDAY EVENING...SCOURING MOST OF THE LINGERING LOW CLOUDS.... AND EVENTUALLY STALLING SOUTH OF THE AREA. THE GFS REMAINS DRY THROUGH TUESDAY...WHILE THE NAM/ECMWF/SREF MEAN BRING ANOTHER WAVE ALONG THE FRONTAL ZONE WITH RAIN CROSSING SC AND SOUTHEASTERN NC MONDAY NIGHT/EARLY TUESDAY. THE WAVE IS SUBTLE IN MODEL GUIDANCE...SO ITS DIFFICULT TO ASSESS HOW FAR NORTH PRECIP WILL REACH .WILL KEEP A SLIGHT CHANCE POP ACROSS THE SOUTH MONDAY NIGHT...WITH DRY CONDITIONS ON TUESDAY. LOWS MONDAY NIGHT MOSTLY IN THE MID TO UPPER 40S. HIGHS TUESDAY IN THE UPPER 50S AND LOWER 60S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 230 PM SATURDAY... AN ACTIVE PATTERN WILL CONTINUE THROUGH LATE NEXT WEEK AS BOTH THE NORTHERN AND SOUTHERN STREAM SUPPLY DISTURBANCES WITHIN A BROAD AND STRENGTHENING MEAN TROUGH COVERING MOST OF THE CONUS. MODELS ARE IN GOOD AGREEMENT ON A A PIECE OF ENERGY EJECTING OUT OF THE ROCKIES AND RUSHING EAST AND SHEARING OUT AS IT CROSSES OUR AREA WEDNESDAY. WEAK LOW PRESSURE ALONG THE GULF COAST SHOULD TRACK ALONG A STALLED OUR FRONT OVER THE SOUTHEAST US AND BE OFF THE CAROLINA/VA BY WEDNESDAY EVENING. PRECIP IS EXPECTED TO BE MOSTLY LIGHT ON THE COOL SIDE OF THE FRONT AND SURFACE LOW...WITH FORECAST SOUNDINGS SHOWING A WARM LAYER BELOW 10K FT THAT WOULD KEEP PRECIP PREDOMINATELY LIQUID. THE ECMWF DOES BRING THE 1000-850MB THICKNESS DOWN TO NEAR 1300M WEDNESDAY EVENING DUE A MORE SUPPRESSED TRACK OF THE 850MB WAVE....WHICH ESSENTIALLY TRACKS OVER OR JUST TOT HE SOUTHEAST OF THE CWA. HOWEVER...THIS WOULD BE ON THE TAIL END OF THE DEEPER MOISTURE...SO WILL KEEP PRECIP ALL LIQUID AND MONITOR FUTURE TRENDS IN THE LOW TRACK/STRENGTH. COOL HIGHS ON WEDNESDAY WILL SLOWLY TREND UPWARD TO SLIGHTLY ABOVE NORMAL THURSDAY AND FRIDAY BEFORE THE UPPER TROUGH BEGINS TO AMPLIFY AND SHIFT TOWARD THE EAST COAST NEXT WEEKEND. MODELS ARE ADVERTISING THE POTENTIAL FOR A STRONG EAST COAST STORM...AND WHILE THE DETAILS OF ITS IMPACT ARE STILL UNCERTAIN...CURRENT MODEL PROJECTIONS SHOW CYCLOGENESIS MORE TOWARD THE MID ATLANTIC COAST...WITH LESS QPF OVER THE CAROLINAS BUT TEMPS BELOW NORMAL. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 1230 PM SATURDAY... HIGH CONFIDENCE THAT VFR CONDITIONS WILL HOLD THROUGH SUNDAY. SURFACE HIGH PRESSURE AND RIDGING ALOFT WILL KEEP SKIES CLEAR INTO THIS EVENING. WINDS FROM THE NW AND WNW AT SPEEDS VARYING FROM 5 TO 10 KTS SUSTAINED WITH PERIODIC GUSTS TO 15-18 KTS WILL DIMINISH BY 21Z TO LIGHT MAINLY FROM THE NORTH BY EVENING BEFORE SWINGING AROUND TO EAST THEN SE TONIGHT. THE STORM SYSTEM NOW OVER THE SOUTHWEST STATES WILL SHIFT ENE THROUGH TONIGHT AND AS IT APPROACHES... HIGH CLOUDS WILL INCREASE AND THICKEN WITH LOWERING BASES TO AROUND 12 THOUSAND FT AGL BY SUNDAY AFTERNOON. LOOKING BEYOND 18Z SUNDAY... GOOD CHANCE OF CIGS/VSBYS DROPPING TO IFR/LIFR WITHIN AREAS OF RAIN SUNDAY EVENING AS LOW LEVEL FLOW FROM THE S AND SW INCREASES AHEAD OF THE INCOMING FRONTAL SYSTEM. THESE STRONG LOW LEVEL WINDS MAY INDUCE MECHANICAL TURBULENCE. SUB-VFR CONDITIONS WILL HOLD THROUGH MIDDAY MONDAY BEFORE LIKELY IMPROVING TO VFR BEHIND THE FRONT DURING MONDAY AFTERNOON. YET ANOTHER STORM SYSTEM MAY BRING ANOTHER ROUND OF SUB-VFR CONDITIONS LATE TUESDAY NIGHT THROUGH WEDNESDAY... FOLLOWED BY A POSSIBLE TREND BACK UP TO VFR BY THURSDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BSD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1230 PM EST SAT FEB 9 2013 .SYNOPSIS... HIGH PRESSURE WILL SETTLE OVER THE EAST COAST TONIGHT THROUGH SUNDAY MORNING... BEFORE SHIFTING OFFSHORE SUNDAY AFTERNOON. A STORM SYSTEM WILL APPROACH FROM THE WEST LATE SUNDAY AND SWEEP THROUGH THE AREA SUNDAY NIGHT AND MONDAY. YET ANOTHER SYSTEM WILL AFFECT THE REGION TUESDAY NIGHT AND WEDNESDAY. && .NEAR TERM /THROUGH SUNDAY/... AS OF 920 AM SATURDAY... THROUGH TODAY: LOTS OF SUN TODAY WITH AREA AND UPSTREAM RADIOSONDE DATA SHOWING VERY DRY AIR THROUGH THE COLUMN AND FAST CONFLUENT NW FLOW ALOFT WITH STRONG DEEP SUBSIDENCE TAKING PLACE. SOUNDING DATA ALSO SHOWS 20-30 KTS OF WIND THIS MORNING THROUGH THE SHALLOW MIXED LAYER JUST OFF THE SURFACE... ALTHOUGH THIS WILL BE DIMINISHING AS THE DAY GOES ON AS THE 925 MB ANTICYCLONE AND SURFACE RIDGE CENTER OVER THE LOWER GREAT LAKES BUILDS SOUTHEAST WITH A NEW CENTER FORMING OVER THE WRN CAROLINAS LATER TODAY. WILL RETAIN BREEZY CONDITIONS AND OCCASIONAL GUSTS MAINLY IN THE EAST UNTIL EARLY AFTERNOON. THE DRY-ADIABATIC THERMAL PROFILE FROM THE RAP MODEL OUTPUT SUPPORTS HIGHS OF 50 TO 59 (NE TO SW). -GIH TONIGHT: SURFACE HIGH PRESSURE WILL SETTLE OVER THE REGION TONIGHT... WITH RIDING ALOFT OVERHEAD. HOWEVER... WE WILL BEGIN TO SEE SOME HIGH CLOUD FILTER INTO THE REGION FROM THE NEXT S/W TROUGH AND ASSOCIATED COLD FRONT APPROACHING THE AREA FROM THE CENTRAL U.S. THIS MAY IMPACT OVERNIGHT LOW TEMPS A BIT... MOST ACROSS THE WEST. THUS... WILL SHOW LOW TEMPS RANGING FROM THE MID TO LOWER 20S EAST AND USUAL RURAL COLD OUTLYING AREAS (EXCEPT FOR THE FAR WESTERN PORTIONS OF THE CWA) TO THE UPPER 20 TO NEAR 30 IN THE FAR WEST AND URBAN AREAS. SUNDAY: MAINLY MID AND HIGH LEVEL CLOUD COVER WILL BE ON THE INCREASE ACROSS THE AREA ON SUNDAY... AS BOTH THE SURFACE HIGH AND RIDGING ALOFT SLIDE TO THE EAST OF THE AREA. EXPECT ANY RAIN TO REMAIN TO THE WEST OF THE AREA THROUGH EARLY SUNDAY EVENING AS BOTH THE NAM AND GFS BUFR SOUNDINGS SHOW A GOOD DEAL OF DRY AIR BELOW 600 MB ACROSS CENTRAL NC. GIVEN THE INCREASING CLOUD COVER AND ONLY ON AVERAGE OF 5 TO 10 METER INCREASE IN LOW LEVEL THICKNESS VALUES WILL KEEP TEMPS ON THE COOL SIDE OF GUIDANCE AND GO WITH HIGHS RANGING FROM 53 NORTH TO 59 SOUTH... NEAR NORMAL FOR THIS TIME OF YEAR. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS OF 300 AM SATURDAY... SUNDAY NIGHT AND MONDAY...LOW LEVEL SLY FLOW ON THE BACK SIDE OF THE SURFACE RIDGE WILL INCREASE OVER CENTRAL NC SUNDAY NIGHT INTO MONDAY MORNING. THE ADVECTION OF THE MOIST WARM AIR OVER THE RESIDUAL COLL DRY AIR MASS DEPOSITED BY THE RETREATING SURFACE RIDGE WILL SET UP AN OVERRUNNING RAIN EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING. EXPECT RAIN TO COMMENCE IN OUR WESTERN COUNTIES PRIOR TO MIDNIGHT...AND OVERSPREAD THE REMAINDER OF CENTRAL NC LATE SUNDAY NIGHT THROUGH EARLY MONDAY. MIN TEMPS NEAR 40 NE TO THE MID-UPPER 40S SOUTH-SOUTHWEST. BULK OF LIFT/MOISTURE WILL MOVE E-SE OF CENTRAL NC MONDAY AFTERNOON-EVENING. THUS...EXPECT RAIN TO DIMINISH NW-SE. A SURFACE COLD FRONT ASSOCIATED WITH A DEEP LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL REMAIN WEST OF OUR AREA MONDAY. THE DIFFERENCE IN PRESSURE BETWEEN THE HIGH OFFSHORE AND THE LOW WILL CAUSE BREEZY SW WINDS MONDAY AFTERNOON. MOST LOCATIONS WILL SEE GUSTS BETWEEN 20-25 MPH. THIS FLOW WILL LIKELY SCOUR OUT THE RAIN-COOLED PIEDMONT AIR MASS. THIS SUGGEST A BUMP UP IN AFTERNOON TEMPS FROM THE PREVIOUS FORECAST. EXPECT MAX TEMPS MONDAY NEAR 60 NW TO CLOSE TO 70 SE. THESE NUMBERS FAVOR THE COOL SIDE OF MOS GUIDANCE. MONDAY NIGHT AND TUESDAY...THE DEEP LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL OPEN UP AND MOVE ENE ACROSS ONTARIO/QUEBEC. THIS WILL CAUSE THE FLOW OVER CENTRAL NC TO BECOME MORE WLY...PUSHING THE SURFACE COLD FRONT THROUGH OUR REGION MONDAY NIGHT. FRONTAL PASSAGE WILL LIKELY BE UNEVENTFUL...ASIDE FROM A FEW STRAY SHOWERS OVER THE FAR SOUTH-SE EARLY IN THE EVENING. DRIER AIR BEHIND THE FRONT WILL LIMIT PRECIP CHANCES THROUGH TUESDAY AFTERNOON. THE APPROACH OF A MID-UPPER LEVEL LOW PRESSURE SYSTEM FROM THE WEST WILL BRING MOISTURE BACK INTO OUR SOUTHERN COUNTIES TUESDAY AFTERNOON...CAUSING A THREAT OF RAIN FOR AREAS SOUTH OF HIGHWAY 64 LATE IN THE DAY. MIN TEMPS MONDAY NIGHT MID 40S TO NEAR 50. HIGH TEMPS TUESDAY 59-64. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... AS OF 327 AM SATURDAY... TUESDAY NIGHT INTO WEDNESDAY...THE APPROACH OF A MID-UPPER LEVEL LOW PRESSURE SYSTEM FROM THE WEST WILL INDUCE A SURFACE LOW TO DEVELOP OVER THE NORTHERN GULF COAST TUESDAY AND LIFT NEWD TUESDAY NIGHT ALONG A SURFACE FRONT THAT WILL LIE ACROSS GA-SOUTHERN SC. MEANWHILE A WEAK AREA OF HIGH PRESSURE ORIENTATED WEST-TO-EAST ACROSS THE NORTHERN MID ATLANTIC WILL MAINTAIN A FLOW OF RELATIVELY COOL DRY SURFACE AIR ACROSS VA AND POSSIBLY NORTHERN NC. THE RAIN SHIELD ASSOCIATED WITH GULF LOW IS PROJECTED TO REACH INTO OUR SOUTHERN COUNTIES LATE TUESDAY AFTERNOON...AND CREEP NWD TUESDAY NIGHT INTO WEDNESDAY. PRESENCE OF COOLER/DRIER SURFACE AIR ACROSS OUR NORTHERN COUNTIES WILL INITIALLY LIMIT PRECIP FROM REACHING THE SURFACE BUT EXPECT AIR MASS TO SATURATE ENOUGH BY LATE TUESDAY NIGHT INTO WEDNESDAY MORNING FOR RAIN TO REACH THE GROUND. THE CORE OF THE MID-UPPER LEVEL LOW WILL CROSS CENTRAL NC WED AFTERNOON-EVENING. GFS BUFKIT SOUNDINGS SUGGEST THAT THE RAIN MAY MIX WITH A LITTLE WET SNOW OVER THE NW PIEDMONT BEFORE ENDING. WHILE THIS SCENARIO CANNOT BE RULED OUT...OTHER PARAMETERS...SUCH AS PARTIAL THICKNESS SCHEME...SUGGEST THAT THE LOWER LEVELS WILL REMAIN WARM ENOUGH TO PREVENT SNOW FROM REACHING THE SURFACE. THUS...WILL KEEP PRECIP ALL LIQUID FOR NOW. THE PASSAGE OF THE MID-UPPER LEVEL LOW PRESSURE SYSTEM WED EVENING WILL CAUSE PRECIP CHANCES TO DIMINISH/DWINDLE WEST-TO-EAST ACROSS CENTRAL NC. W-NW FLOW WILL ADVECT DRIER AND COOLER AIR...LEADING TO DECREASING CLOUDINESS WED NIGHT. CENTRAL NC WILL BE BETWEEN TWO MAIN BRANCHES OF THE UPPER LEVEL JET THU AND FRI WITH THE NORTHERN BRANCH MORE ENERGETIC. THIS TYPE PF PATTERN USUALLY FAVORS DRY WEATHER WITH SPORADIC PERIODS OF MID-HIGH LEVEL CLOUDINESS AND TEMPS NEAR TO SLIGHTLY ABOVE NORMAL. EXPECT DRY WEATHER THU-FRI. MAX TEMPS IN THE 50S THU...MODERATING TO 55-60 FRI. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 1230 PM SATURDAY... HIGH CONFIDENCE THAT VFR CONDITIONS WILL HOLD THROUGH SUNDAY. SURFACE HIGH PRESSURE AND RIDGING ALOFT WILL KEEP SKIES CLEAR INTO THIS EVENING. WINDS FROM THE NW AND WNW AT SPEEDS VARYING FROM 5 TO 10 KTS SUSTAINED WITH PERIODIC GUSTS TO 15-18 KTS WILL DIMINISH BY 21Z TO LIGHT MAINLY FROM THE NORTH BY EVENING BEFORE SWINGING AROUND TO EAST THEN SE TONIGHT. THE STORM SYSTEM NOW OVER THE SOUTHWEST STATES WILL SHIFT ENE THROUGH TONIGHT AND AS IT APPROACHES... HIGH CLOUDS WILL INCREASE AND THICKEN WITH LOWERING BASES TO AROUND 12 THOUSAND FT AGL BY SUNDAY AFTERNOON. LOOKING BEYOND 18Z SUNDAY... GOOD CHANCE OF CIGS/VSBYS DROPPING TO IFR/LIFR WITHIN AREAS OF RAIN SUNDAY EVENING AS LOW LEVEL FLOW FROM THE S AND SW INCREASES AHEAD OF THE INCOMING FRONTAL SYSTEM. THESE STRONG LOW LEVEL WINDS MAY INDUCE MECHANICAL TURBULENCE. SUB-VFR CONDITIONS WILL HOLD THROUGH MIDDAY MONDAY BEFORE LIKELY IMPROVING TO VFR BEHIND THE FRONT DURING MONDAY AFTERNOON. YET ANOTHER STORM SYSTEM MAY BRING ANOTHER ROUND OF SUB-VFR CONDITIONS LATE TUESDAY NIGHT THROUGH WEDNESDAY... FOLLOWED BY A POSSIBLE TREND BACK UP TO VFR BY THURSDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BSD SHORT TERM...WSS LONG TERM...WSS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
922 AM EST SAT FEB 9 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE CAROLINAS TODAY AND SETTLE OVERHEAD TONIGHT THROUGH EARLY SUNDAY. THE HIGH WILL DRIFT OFFSHORE LATE SUNDAY. SOUTHERLY FLOW ON THE BACK SIDE OF THE HIGH WILL ADVECT MOIST AIR INTO THE CAROLINAS SUNDAY NIGHT. && .NEAR TERM /THROUGH SUNDAY/... AS OF 920 AM SATURDAY... THROUGH TODAY: LOTS OF SUN TODAY WITH AREA AND UPSTREAM RADIOSONDE DATA SHOWING VERY DRY AIR THROUGH THE COLUMN AND FAST CONFLUENT NW FLOW ALOFT WITH STRONG DEEP SUBSIDENCE TAKING PLACE. SOUNDING DATA ALSO SHOWS 20-30 KTS OF WIND THIS MORNING THROUGH THE SHALLOW MIXED LAYER JUST OFF THE SURFACE... ALTHOUGH THIS WILL BE DIMINISHING AS THE DAY GOES ON AS THE 925 MB ANTICYCLONE AND SURFACE RIDGE CENTER OVER THE LOWER GREAT LAKES BUILDS SOUTHEAST WITH A NEW CENTER FORMING OVER THE WRN CAROLINAS LATER TODAY. WILL RETAIN BREEZY CONDITIONS AND OCCASIONAL GUSTS MAINLY IN THE EAST UNTIL EARLY AFTERNOON. THE DRY-ADIABATIC THERMAL PROFILE FROM THE RAP MODEL OUTPUT SUPPORTS HIGHS OF 50 TO 59 (NE TO SW). -GIH TONIGHT: SURFACE HIGH PRESSURE WILL SETTLE OVER THE REGION TONIGHT... WITH RIDING ALOFT OVERHEAD. HOWEVER... WE WILL BEGIN TO SEE SOME HIGH CLOUD FILTER INTO THE REGION FROM THE NEXT S/W TROUGH AND ASSOCIATED COLD FRONT APPROACHING THE AREA FROM THE CENTRAL U.S. THIS MAY IMPACT OVERNIGHT LOW TEMPS A BIT... MOST ACROSS THE WEST. THUS... WILL SHOW LOW TEMPS RANGING FROM THE MID TO LOWER 20S EAST AND USUAL RURAL COLD OUTLYING AREAS (EXCEPT FOR THE FAR WESTERN PORTIONS OF THE CWA) TO THE UPPER 20 TO NEAR 30 IN THE FAR WEST AND URBAN AREAS. SUNDAY: MAINLY MID AND HIGH LEVEL CLOUD COVER WILL BE ON THE INCREASE ACROSS THE AREA ON SUNDAY... AS BOTH THE SURFACE HIGH AND RIDGING ALOFT SLIDE TO THE EAST OF THE AREA. EXPECT ANY RAIN TO REMAIN TO THE WEST OF THE AREA THROUGH EARLY SUNDAY EVENING AS BOTH THE NAM AND GFS BUFR SOUNDINGS SHOW A GOOD DEAL OF DRY AIR BELOW 600 MB ACROSS CENTRAL NC. GIVEN THE INCREASING CLOUD COVER AND ONLY ON AVERAGE OF 5 TO 10 METER INCREASE IN LOW LEVEL THICKNESS VALUES WILL KEEP TEMPS ON THE COOL SIDE OF GUIDANCE AND GO WITH HIGHS RANGING FROM 53 NORTH TO 59 SOUTH... NEAR NORMAL FOR THIS TIME OF YEAR. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS OF 300 AM SATURDAY... SUNDAY NIGHT AND MONDAY...LOW LEVEL SLY FLOW ON THE BACK SIDE OF THE SURFACE RIDGE WILL INCREASE OVER CENTRAL NC SUNDAY NIGHT INTO MONDAY MORNING. THE ADVECTION OF THE MOIST WARM AIR OVER THE RESIDUAL COLL DRY AIR MASS DEPOSITED BY THE RETREATING SURFACE RIDGE WILL SET UP AN OVERRUNNING RAIN EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING. EXPECT RAIN TO COMMENCE IN OUR WESTERN COUNTIES PRIOR TO MIDNIGHT...AND OVERSPREAD THE REMAINDER OF CENTRAL NC LATE SUNDAY NIGHT THROUGH EARLY MONDAY. MIN TEMPS NEAR 40 NE TO THE MID-UPPER 40S SOUTH-SOUTHWEST. BULK OF LIFT/MOISTURE WILL MOVE E-SE OF CENTRAL NC MONDAY AFTERNOON-EVENING. THUS...EXPECT RAIN TO DIMINISH NW-SE. A SURFACE COLD FRONT ASSOCIATED WITH A DEEP LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL REMAIN WEST OF OUR AREA MONDAY. THE DIFFERENCE IN PRESSURE BETWEEN THE HIGH OFFSHORE AND THE LOW WILL CAUSE BREEZY SW WINDS MONDAY AFTERNOON. MOST LOCATIONS WILL SEE GUSTS BETWEEN 20-25 MPH. THIS FLOW WILL LIKELY SCOUR OUT THE RAIN-COOLED PIEDMONT AIR MASS. THIS SUGGEST A BUMP UP IN AFTERNOON TEMPS FROM THE PREVIOUS FORECAST. EXPECT MAX TEMPS MONDAY NEAR 60 NW TO CLOSE TO 70 SE. THESE NUMBERS FAVOR THE COOL SIDE OF MOS GUIDANCE. MONDAY NIGHT AND TUESDAY...THE DEEP LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL OPEN UP AND MOVE ENE ACROSS ONTARIO/QUEBEC. THIS WILL CAUSE THE FLOW OVER CENTRAL NC TO BECOME MORE WLY...PUSHING THE SURFACE COLD FRONT THROUGH OUR REGION MONDAY NIGHT. FRONTAL PASSAGE WILL LIKELY BE UNEVENTFUL...ASIDE FROM A FEW STRAY SHOWERS OVER THE FAR SOUTH-SE EARLY IN THE EVENING. DRIER AIR BEHIND THE FRONT WILL LIMIT PRECIP CHANCES THROUGH TUESDAY AFTERNOON. THE APPROACH OF A MID-UPPER LEVEL LOW PRESSURE SYSTEM FROM THE WEST WILL BRING MOISTURE BACK INTO OUR SOUTHERN COUNTIES TUESDAY AFTERNOON...CAUSING A THREAT OF RAIN FOR AREAS SOUTH OF HIGHWAY 64 LATE IN THE DAY. MIN TEMPS MONDAY NIGHT MID 40S TO NEAR 50. HIGH TEMPS TUESDAY 59-64. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... AS OF 327 AM SATURDAY... TUESDAY NIGHT INTO WEDNESDAY...THE APPROACH OF A MID-UPPER LEVEL LOW PRESSURE SYSTEM FROM THE WEST WILL INDUCE A SURFACE LOW TO DEVELOP OVER THE NORTHERN GULF COAST TUESDAY AND LIFT NEWD TUESDAY NIGHT ALONG A SURFACE FRONT THAT WILL LIE ACROSS GA-SOUTHERN SC. MEANWHILE A WEAK AREA OF HIGH PRESSURE ORIENTATED WEST-TO-EAST ACROSS THE NORTHERN MID ATLANTIC WILL MAINTAIN A FLOW OF RELATIVELY COOL DRY SURFACE AIR ACROSS VA AND POSSIBLY NORTHERN NC. THE RAIN SHIELD ASSOCIATED WITH GULF LOW IS PROJECTED TO REACH INTO OUR SOUTHERN COUNTIES LATE TUESDAY AFTERNOON...AND CREEP NWD TUESDAY NIGHT INTO WEDNESDAY. PRESENCE OF COOLER/DRIER SURFACE AIR ACROSS OUR NORTHERN COUNTIES WILL INITIALLY LIMIT PRECIP FROM REACHING THE SURFACE BUT EXPECT AIR MASS TO SATURATE ENOUGH BY LATE TUESDAY NIGHT INTO WEDNESDAY MORNING FOR RAIN TO REACH THE GROUND. THE CORE OF THE MID-UPPER LEVEL LOW WILL CROSS CENTRAL NC WED AFTERNOON-EVENING. GFS BUFKIT SOUNDINGS SUGGEST THAT THE RAIN MAY MIX WITH A LITTLE WET SNOW OVER THE NW PIEDMONT BEFORE ENDING. WHILE THIS SCENARIO CANNOT BE RULED OUT...OTHER PARAMETERS...SUCH AS PARTIAL THICKNESS SCHEME...SUGGEST THAT THE LOWER LEVELS WILL REMAIN WARM ENOUGH TO PREVENT SNOW FROM REACHING THE SURFACE. THUS...WILL KEEP PRECIP ALL LIQUID FOR NOW. THE PASSAGE OF THE MID-UPPER LEVEL LOW PRESSURE SYSTEM WED EVENING WILL CAUSE PRECIP CHANCES TO DIMINISH/DWINDLE WEST-TO-EAST ACROSS CENTRAL NC. W-NW FLOW WILL ADVECT DRIER AND COOLER AIR...LEADING TO DECREASING CLOUDINESS WED NIGHT. CENTRAL NC WILL BE BETWEEN TWO MAIN BRANCHES OF THE UPPER LEVEL JET THU AND FRI WITH THE NORTHERN BRANCH MORE ENERGETIC. THIS TYPE PF PATTERN USUALLY FAVORS DRY WEATHER WITH SPORADIC PERIODS OF MID-HIGH LEVEL CLOUDINESS AND TEMPS NEAR TO SLIGHTLY ABOVE NORMAL. EXPECT DRY WEATHER THU-FRI. MAX TEMPS IN THE 50S THU...MODERATING TO 55-60 FRI. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 640 AM SATURDAY... 24-HR TAF PERIOD: VFR CONDITIONS WILL CONTINUE FOR THE 24 HOUR TAF PERIOD. HIGH PRESSURE WILL BUILD INTO THE AREA TODAY... THEN SETTLE OVER THE REGION TONIGHT. THIS WILL YIELD GENERALLY CLEAR SKIES AND VFR CONDITIONS. WEST TO WEST-NORTHWESTERLY WINDS EARLY THIS MORNING WILL BECOME NORTHWESTERLY AFTER SUNRISE AND THIS AFTERNOON... WITH WINDS SPEEDS GENERALLY IN THE 8 TO 15 MPH RANGE. HOWEVER... WE COULD SEE A BRIEF PERIOD OF WIND GUSTS AROUND 20 MPH AFTER SUNRISE THIS MORNING UNTIL THE EARLY AFTERNOON ACROSS THE EASTERN TAF SITES (MAINLY KRWI). WINDS WILL QUICKLY BECOME LIGHT/VARIABLE THIS EVENING WITH THE LOSS OF DIURNAL HEATING AND HIGH PRESSURE BUILDING OVERHEAD. LOOKING AHEAD: VFR CONDITIONS WILL PERSIST THROUGH SUNDAY AS HIGH PRESSURE SLOWLY SHIFTS TO THE EAST OF THE AREA. THE NEXT CHANCE FOR SUB-VFR CONDITIONS (IFR/LIFR CEILINGS/RAIN) WILL BE SUNDAY NIGHT AND MONDAY IN ASSOC/W AN IN-SITU COLD AIR DAMMING WEDGE EXPECTED TO DEVELOP OVER THE CAROLINAS. ADVERSE AVIATION CONDITIONS MAY LINGER OR RE-DEVELOP ACROSS PORTIONS OF THE AREA INTO MIDWEEK... ESPECIALLY ACROSS THE EASTERN TAF SITES. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD/BSD SHORT TERM...WSS LONG TERM...WSS AVIATION...BSD/VINCENT
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
955 PM EST SUN FEB 10 2013 .SYNOPSIS... LOW PRESSURE TRACKING OUT OF THE PLAINS WILL MOVE THROUGH THE UPPER GREAT LAKES ON MONDAY...PULLING AWAY TO THE NORTHEAST ON TUESDAY. A RIDGE WILL EXPAND NORTH ACROSS THE OHIO VALLEY ON TUESDAY AND LINGER INTO WEDNESDAY. A CLIPPER WILL APPROACH THE REGION FROM THE NORTHWEST ON THURSDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... THE FRONT WILL MOVE ACROSS THE AREA LATE TONIGHT AND MONDAY MORNING. THE FIRST BATCH OF SHOWERS HAVE DECREASED...SOME SPRINKLES COULD BE OCCURRING OVER NW PA THROUGH MIDNIGHT. THE DEW POINTS ARE LOW OVER NW PA BUT THE TEMPERATURES ARE WARM ENOUGH AND WILL CONTINUE TO RISE AS WILL THE DEW POINTS. THE THREAT OF THE TEMPERATURE DROPPING TO 32F IS NEGLIGIBLE. ALSO THE ROAD TEMPERATURES ARE NEAR 40F...SO THAT WILL ALSO HELP PREVENT ANY ICY ROADS. THE NEXT BATCH OF SHOWERS WERE TRYING TO DEVELOP OVER WESTERN OHIO. THE HRRR MODEL IS HINTING AT IT...MORE OF A SCATTERED NATURE. THE 12Z 4KM WRF NMM MODEL IS HINTING AT WIDESPREAD SHOWERS DEVELOPING AFTER MIDNIGHT. THAT IS POSSIBLE WITH ENOUGH MOISTURE...PLENTY OF OMEGA AND SOME LOW LEVEL AND UPPER JET HELP...LEFT FRONT QUAD OF THE JET. KEPT THE POPS LIKELY FOR THE OVERNIGHT. CONFIDENCE IS LOW TO MODERATE. RAINFALL AMOUNTS WILL BE UNDER TWO TENTHS OF AN INCH. ADJUSTED SOME OF THE LOWS BASED ON A SLOWER TIMING OF THE FRONT. ALSO REMOVED THE MENTION OF THUNDER AS THE AIRMASS IS TOO STABLE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/... BY MONDAY MORNING THE MID-LEVEL DRY SLOT WILL HAVE SPREAD EAST ACROSS OUR ENTIRE FORECAST AREA WITH DRY CONDITIONS IN MOST AREAS. HAVE LOWERED POPS IN THE EAST TO JUST A LOW CHANCE AFTER 12Z. THE COLD FRONT WILL MOVE INTO NW OHIO TOWARDS 14Z...CLEARING NW PA DURING THE EARLY AFTERNOON. LOW LEVEL WRAP AROUND MOISTURE WILL INCREASE WITH THE FRONT WITH FAIRLY STEEP LOW LEVEL LAPSE RATES AND ONLY A SLIGHT CHANCE OF RAIN...EVENTUALLY COOLING ENOUGH FOR FLURRIES OR A STRAY SNOW SHOWER LATE. HAVE ISSUED A WIND ADVISORY FOR THE WESTERN HALF OF THE AREA AND LAKESHORE COUNTIES WITH BOTH THE NAM/GFS ADVERTISING A MIXED LAYER TO NEARLY 850MB WHERE WINDS INCREASE TO 50 KNOTS. WITH LITTLE IN THE WAY OF DOWNWARD MOMENTUM WILL HAVE TO RELY ON THE TIGHT PRESSURE GRADIENT AND MECHANICAL MIXING TO SEE THE STRONGER WINDS MATERIALIZE AT THE SURFACE. STILL EXPECTING TO SEE SOUTHWEST WINDS OF 20-30 MPH WITH GUSTS NEAR 50 MPH. TEMPERATURES BEHIND THE LAKE WILL BE MARGINAL FOR LAKE EFFECT BUT ENOUGH CONVERGENCE ALONG THE SHORELINE SHOULD BE ENOUGH FOR LINGERING SNOW SHOWERS EXTREME NE OHIO/NW PA. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION. A RIDGE WILL EXPAND NORTH OVER THE AREA THROUGH TUESDAY WITH SNOW SHOWERS ENDING BY TUESDAY NIGHT. A SHORTWAVE DROPS THROUGH THE NORTHWEST FLOW ON TUESDAY AND HELPS TO RE-ENFORCE THE TROUGH OVER THE GREAT LAKES. THIS SHOULD HELP TO KEEP LOW PRESSURE SYSTEM EAST OF THE APPALACHIANS ON WEDNESDAY. && .LONG TERM /THURSDAY THROUGH SUNDAY/... THE MODELS HAVE BEEN PRETTY CONSISTENT DEEPENING THE TROUGH ALOFT LATE IN THE WEEK. THE FIRST IN A SERIES OF COLD FRONTS SEEMS TO CROSS THE AREA LATE THURSDAY. NOT MUCH MOISTURE AVAILABLE AND THE FRONT IS WEAK AND WILL HAVE JUST A SLIGHT CHANCE OF SHOWERS THURSDAY AFTERNOON...WITH A CHANCE OF SOME SNOW SHOWERS DEVELOPING THURSDAY NIGHT. APPEARS AS THOUGH A REINFORCING PUNCH OF COLDER AIR WILL ARRIVE FRIDAY AND WILL HAVE A CHANCE OF SNOW SHOWERS FOR THE ENTIRE FORECAST AREA ALTHOUGH AS WE GET CLOSER WE WILL PROBABLY NEED "LIKELY" POPS...PROBABLY AT LEAST FOR NE OH/NW PA. A LITTLE NERVOUS WITH SUCH A DEEP TROUGH PROGGED BY THE WEEKEND THAT SOME CYCLOGENESIS COULD OCCUR BUT PERHAPS IT IS ALL TO THE EAST NEAR THE COAST? IN ANY CASE...WE WILL CONTINUE TO SEE SNOW FLURRIES AND LAKE EFFECT SNOW SHOWERS THIS WEEKEND. NUDGED TEMPERATURES DOWN A COUPLE OF CATEGORIES BY THE WEEKEND WITH HIGHS IN THE 20S AND LOWS MOSTLY IN THE TEENS. WE CAN REFINE THE FORECAST AS WE GET CLOSER. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... PRECIPITATION IS REALLY STRUGGLING TO GET GOING OVER THE FORECAST AREA AS IT ENCOUNTERS DRIER AIR. WILL MENTION RAIN AS THE BOUNDARY MOVES THROUGH THE REGION THIS EVENING AND THEN KEEP IT DRY AFTER THAT. CEILINGS AND VISIBILITIES SHOULD REMAIN VFR THROUGH MUCH OF THE PERIOD. WINDS ARE GOING TO BE THE PROBLEM OVERNIGHT INTO TOMORROW AS THEY BECOME QUITE GUSTY FROM THE SOUTH TO SOUTHWEST. OTHER PROBLEM WILL BE WIND SHEAR POTENTIAL AT ALL SITES EXCEPT ERIE. EXPECTING SURFACE WINDS TO BE RELATIVELY LIGHT BUT THEN INCREASE IN SPEED DRAMATICALLY TO AROUND 50 KNOTS JUST ABOVE THE SURFACE. THEREFORE...WILL KEEP MENTION OF WIND SHEAR OVERNIGHT. OUTLOOK...NON-VFR MONDAY NIGHT AND CONTINUING INTO TUESDAY. && .MARINE... STRONG LOW PRESSURE WILL TRACK ACROSS THE NORTHERN GREAT LAKES LATER TONIGHT AND MIDDAY. THE ASSOCIATED COLD FRONT WILL SWING ACROSS LAKE ERIE MONDAY MORNING. AS THE COLD ADVECTION DEVELOPS THE HIGHER WINDS WILL MIX DOWN TO THE SURFACE AND GALE FORCE WINDS ARE LIKELY MONDAY AFTERNOON INTO MONDAY NIGHT. THE ICE ON THE LAKE WILL LIKELY SHIFT MONDAY INTO TUESDAY. THE LOW WILL PULL OUT QUICKLY ON TUESDAY AND HIGH PRESSURE WILL BUILD IN FROM THE WEST AND THE MIDDLE OF THE WEEK SHOULD BE RELATIVELY QUIET ON THE LAKE. A SERIES OF COLD FRONTS AND CLIPPER LOW PRESSURE SYSTEMS ARE EXPECTED LATE IN THE WEEK. THE SOUTHWEST FLOW WILL SHIFT TO NORTHWEST AND WINDS WILL INCREASE LATE IN THE WEEK... PROBABLY IN THE 15 TO 30 KNOT RANGE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...WIND ADVISORY FROM 11 AM MONDAY TO 1 AM EST TUESDAY FOR OHZ011- 012-089. WIND ADVISORY FROM 9 AM TO 7 PM EST MONDAY FOR OHZ003-006>010- 017>020-027>030-036-037. PA...WIND ADVISORY FROM 11 AM MONDAY TO 1 AM EST TUESDAY FOR PAZ001. MARINE...GALE WARNING FROM NOON MONDAY TO 4 AM EST TUESDAY FOR LEZ061- 142>149-162>169. && $$ SYNOPSIS...KEC NEAR TERM...KIELTYKA SHORT TERM...KEC LONG TERM...KOSARIK AVIATION...LOMBARDY MARINE...KOSARIK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
827 PM EST SUN FEB 10 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE AREA TONIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA ON MONDAY AND REMAIN ACROSS THE REGION FOR TUESDAY. A STORM SYSTEM WILL MOVE SOUTH OF THE AREA ON WEDNESDAY BRINGING A CHANCE FOR PRECIPITATION TO SOUTHERN PORTIONS OF THE REGION. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... MAIN AREA OF PCPN IS EXITING OUR EASTERN AREAS SO WILL TRIM BACK POPS ACROSS THE EAST IN THE SHORT TERM. PCPN IS TRYING TO FILL IN ACROSS INDIANA AS SUGGESTED BY THE NAM AND HRRR BUT SO FAR IT STILL APPEARS TO BE PRETTY LIGHT. WILL ALLOW FOR CHANCE POPS ASSOCIATED WITH THIS TO SPREAD BACK EAST ACROSS OUR AREA THROUGH THE LATE EVENING AND ON INTO THE EARLY MORNING HOURS BUT EXPECT ANY MEASURABLE PCPN TO BE ON THE LIGHT SIDE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... HIGH PRESSURE WILL BEGIN TO WORK INTO THE FA ON MONDAY. THERE WILL BE A BREAK IN THE CLOUDS DURING THE MORNING HOURS ACROSS THE FA. IT IS DURING THIS TIME THAT WINDS WILL INCREASE ACROSS THE FA AND EXPECT THE HIGHEST WINDS ACROSS THE FA DURING THE LATE MORNING TO EARLY AFTERNOON TIME FRAME. SUSTAINED WINDS WILL BE AROUND 20 TO 25 MILES PER HOUR WITH WIND GUSTS AROUND 35 TO 45 MILES PER HOUR. THESE WINDS FALL SLIGHTLY BELOW WIND ADVISORY CRITERIA AND THEREFORE DECIDED NOT TO ISSUE A WIND ADVISORY FOR MONDAY. WILL CONTINUE TO HIGHLIGHT THE WINDS IN THE HWO. ADDITIONAL CLOUDS WILL WORK INTO THE AREA FOR THE AFTERNOON HOURS. GUSTY WINDS WILL REMAIN ACROSS THE FA THROUGH THE AFTERNOON AND EVENING HOURS. WINDS WILL DECREASE ACROSS THE AREA MONDAY NIGHT. TEMPERATURES ON MONDAY WILL NOT RISE MUCH FROM SUNDAY NIGHT LOWS. EXPECT HIGH TEMPERATURES ON MONDAY TO BE IN THE LOW TO UPPER 40S. WITH CLOUD COVER DECREASING ACROSS THE FA MONDAY NIGHT TEMPERATURES WILL DROP DOWN INTO THE 20S ACROSS MOST LOCATIONS. HIGH PRESSURE WILL KEEP DRY CONDITIONS ACROSS THE FA TUESDAY AND INTO TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE WILL PASS SOUTH OF THE REGION ON WEDNESDAY. STILL SOME MODEL DISAGREEMENT ON HOW FAR NORTH THE PRECIPITATION SHIELD WILL SPREAD. HAVE LIMITED POPS TO THE FAR SOUTH/SOUTHEASTERN COUNTIES. LOOKS LIKE THIS WOULD BE A MIX OF LIGHT SNOW AND RAIN. ONCE THIS SYSTEM MOVES OFF THERE WILL BE A BRIEF PERIOD OF RIDGING ON THURSDAY. BUT THEN LOW PRESSURE WILL TRACK ACROSS THE GREAT LAKES ON FRIDAY WHICH WILL SWING A COLD FRONT THROUGH THE REGION. COLD NORTHWEST FLOW WILL THEN PREVAIL THROUGH THE WEEKEND. COULD SEE SOME SNOW SHOWERS OR FLURRIES WITH THE FRONT AND INTO THE WEEKEND. BUT NARROWING DOWN A MORE FAVORABLE PERIOD FOR MEASURABLE PRECIPITATION IS PROBLEMATIC THIS FAR OUT IN TIME. SO KEPT POPS MAINLY IN SLIGHT CHANCE CATEGORY. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... SHOWER ACTIVITY HAS STEADILY BEEN DECREASING AS IT HAS PROGRESSED EASTWARD ACROSS WESTERN OHIO. THIS TREND WILL LIKELY CONTINUE OVER THE NEXT HOUR OR SO...BUT IT WILL STILL LIKELY RESULT IN A BRIEF PERIOD OF LIGHT RAIN SHOWERS AT KCMH/KLCK AT THE START OF THE TAF PERIOD. NOT MUCH CURRENTLY GOING ON BACK TO OUR WEST ATTM...BUT BOTH THE 18Z NAM AND LATEST RUNS OF THE HRRR CONTINUE TO SUGGEST SOME SHOWERS REDEVELOPING IN THE NEXT HOUR OR TWO BACK TO OUR WEST AND THEN PUSHING EAST ACROSS OUR AREA LATER THIS EVENING ON INTO THE OVERNIGHT HOURS. WILL COVER THIS THREAT WITH SOME P6SM -SHRA BUT DO EXPECT CIGS TO DROP DOWN INTO MVFR AND POSSIBLY IFR THROUGH THE OVERNIGHT HOURS AS BETTER LOW LEVEL MOISTURE OVERSPREADS THE REGION. A WELL DEFINED DRY SLOT PUSHING INTO WESTERN ILLINOIS ATTM IS FORECAST TO WORK ITS WAY INTO OUR AREA FROM THE WEST TOWARD DAYBREAK. THIS WILL LIKELY RESULT IN AT LEAST SOME PARTIAL CLEARING THROUGH MID TO LATE MORNING. HOWEVER...WRAP AROUND MOISTURE WILL WORK QUICKLY BACK IN BY THE AFTERNOON...LEADING TO A SCT-BKN SC DECK. SOUTHERLY WINDS WILL STAY UP OVERNIGHT AND MAY BE GUSTY AT TIMES...ESPECIALLY IF WE GET SOME REDEVELOPMENT OF THE SHOWERS. ANY CLEARING THROUGH THE MORNING WILL ALLOW FOR GOOD MIXING ON MONDAY. SUSTAINED SOUTHWEST TO WEST WINDS OF 20 TO 25 KNOTS WITH GUSTS UP TO AROUND 35 KNOTS WILL BE POSSIBLE THROUGH MUCH OF THE DAY ON MONDAY. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...NOVAK NEAR TERM...JGL SHORT TERM...NOVAK LONG TERM... AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
640 PM EST SUN FEB 10 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE AREA TONIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA ON MONDAY AND REMAIN ACROSS THE REGION FOR TUESDAY. A STORM SYSTEM WILL MOVE SOUTH OF THE AREA ON WEDNESDAY BRINGING A CHANCE FOR PRECIPITATION TO SOUTHERN PORTIONS OF THE REGION. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A BAND OF RAIN WILL MOVE THROUGH THE FA THIS EVENING. THUNDERSTORMS HAVE BEEN LIMITED HOWEVER THERE IS SOME WEAK INSTABILITY AND THEREFORE ISOLATED THUNDER CANNOT BE RULED OUT ACROSS THE FA THIS EVENING. AFTER THIS INITIAL BAND THERE WILL BE A BRIEF LULL IN THE PRECIPITATION HOWEVER EXPECT SOME ADDITIONAL DEVELOPMENT OF RAIN THAT WILL MOVE ACROSS THE FA TONIGHT. EXPECT ALL RAIN ACTIVITY TO MOVE OUT OF THE AREA BY THE END OF THE NEAR TERM TIME FRAME. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... HIGH PRESSURE WILL BEGIN TO WORK INTO THE FA ON MONDAY. THERE WILL BE A BREAK IN THE CLOUDS DURING THE MORNING HOURS ACROSS THE FA. IT IS DURING THIS TIME THAT WINDS WILL INCREASE ACROSS THE FA AND EXPECT THE HIGHEST WINDS ACROSS THE FA DURING THE LATE MORNING TO EARLY AFTERNOON TIME FRAME. SUSTAINED WINDS WILL BE AROUND 20 TO 25 MILES PER HOUR WITH WIND GUSTS AROUND 35 TO 45 MILES PER HOUR. THESE WINDS FALL SLIGHTLY BELOW WIND ADVISORY CRITERIA AND THEREFORE DECIDED NOT TO ISSUE A WIND ADVISORY FOR MONDAY. WILL CONTINUE TO HIGHLIGHT THE WINDS IN THE HWO. ADDITIONAL CLOUDS WILL WORK INTO THE AREA FOR THE AFTERNOON HOURS. GUSTY WINDS WILL REMAIN ACROSS THE FA THROUGH THE AFTERNOON AND EVENING HOURS. WINDS WILL DECREASE ACROSS THE AREA MONDAY NIGHT. TEMPERATURES ON MONDAY WILL NOT RISE MUCH FROM SUNDAY NIGHT LOWS. EXPECT HIGH TEMPERATURES ON MONDAY TO BE IN THE LOW TO UPPER 40S. WITH CLOUD COVER DECREASING ACROSS THE FA MONDAY NIGHT TEMPERATURES WILL DROP DOWN INTO THE 20S ACROSS MOST LOCATIONS. HIGH PRESSURE WILL KEEP DRY CONDITIONS ACROSS THE FA TUESDAY AND INTO TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE WILL PASS SOUTH OF THE REGION ON WEDNESDAY. STILL SOME MODEL DISAGREEMENT ON HOW FAR NORTH THE PRECIPITATION SHIELD WILL SPREAD. HAVE LIMITED POPS TO THE FAR SOUTH/SOUTHEASTERN COUNTIES. LOOKS LIKE THIS WOULD BE A MIX OF LIGHT SNOW AND RAIN. ONCE THIS SYSTEM MOVES OFF THERE WILL BE A BRIEF PERIOD OF RIDGING ON THURSDAY. BUT THEN LOW PRESSURE WILL TRACK ACROSS THE GREAT LAKES ON FRIDAY WHICH WILL SWING A COLD FRONT THROUGH THE REGION. COLD NORTHWEST FLOW WILL THEN PREVAIL THROUGH THE WEEKEND. COULD SEE SOME SNOW SHOWERS OR FLURRIES WITH THE FRONT AND INTO THE WEEKEND. BUT NARROWING DOWN A MORE FAVORABLE PERIOD FOR MEASURABLE PRECIPITATION IS PROBLEMATIC THIS FAR OUT IN TIME. SO KEPT POPS MAINLY IN SLIGHT CHANCE CATEGORY. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... SHOWER ACTIVITY HAS STEADILY BEEN DECREASING AS IT HAS PROGRESSED EASTWARD ACROSS WESTERN OHIO. THIS TREND WILL LIKELY CONTINUE OVER THE NEXT HOUR OR SO...BUT IT WILL STILL LIKELY RESULT IN A BRIEF PERIOD OF LIGHT RAIN SHOWERS AT KCMH/KLCK AT THE START OF THE TAF PERIOD. NOT MUCH CURRENTLY GOING ON BACK TO OUR WEST ATTM...BUT BOTH THE 18Z NAM AND LATEST RUNS OF THE HRRR CONTINUE TO SUGGEST SOME SHOWERS REDEVELOPING IN THE NEXT HOUR OR TWO BACK TO OUR WEST AND THEN PUSHING EAST ACROSS OUR AREA LATER THIS EVENING ON INTO THE OVERNIGHT HOURS. WILL COVER THIS THREAT WITH SOME P6SM -SHRA BUT DO EXPECT CIGS TO DROP DOWN INTO MVFR AND POSSIBLY IFR THROUGH THE OVERNIGHT HOURS AS BETTER LOW LEVEL MOISTURE OVERSPREADS THE REGION. A WELL DEFINED DRY SLOT PUSHING INTO WESTERN ILLINOIS ATTM IS FORECAST TO WORK ITS WAY INTO OUR AREA FROM THE WEST TOWARD DAYBREAK. THIS WILL LIKELY RESULT IN AT LEAST SOME PARTIAL CLEARING THROUGH MID TO LATE MORNING. HOWEVER...WRAP AROUND MOISTURE WILL WORK QUICKLY BACK IN BY THE AFTERNOON...LEADING TO A SCT-BKN SC DECK. SOUTHERLY WINDS WILL STAY UP OVERNIGHT AND MAY BE GUSTY AT TIMES...ESPECIALLY IF WE GET SOME REDEVELOPMENT OF THE SHOWERS. ANY CLEARING THROUGH THE MORNING WILL ALLOW FOR GOOD MIXING ON MONDAY. SUSTAINED SOUTHWEST TO WEST WINDS OF 20 TO 25 KNOTS WITH GUSTS UP TO AROUND 35 KNOTS WILL BE POSSIBLE THROUGH MUCH OF THE DAY ON MONDAY. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...NOVAK NEAR TERM...NOVAK SHORT TERM...NOVAK LONG TERM... AVIATION...JGL
AREA FORECAST DISCUSSION
NWS NORMAN OK
1011 PM CST FRI FEB 8 2013 .AVIATION... SOUTH WIND SATURDAY MORNING WILL BRING LOW CLOUDS AND A MOIST ATMOSPHERE SOUTH TO NORTH ACROSS OKLAHOMA BY AFTERNOON. LIGHT RAIN IS EXPECTED BEFORE THUNDERSTORMS LATER IN THE EVENING ASSOCIATED WITH A DRYLINE PASSAGE. THUNDERSTORMS COULD BE ONGOING A FEW HOURS BEFORE 110600 IN CENTRAL OKLAHOMA. && .PREV DISCUSSION... /ISSUED 945 PM CST FRI FEB 8 2013/ UPDATE... VERY FEW CHANGES WERE MADE TO THE ONGOING FORECAST. WITH INCREASING LOW/MID LEVEL MOISTURE OVERNIGHT...EXPECT CLOUD COVER TO CONTINUE TO EXPAND AND LOWER. RECENT HRRR RUNS DEPICT AREA OF VERY LIGHT SHOWERS/DRIZZLE MAY DEVELOP AROUND 09Z AND MOVE INTO TX AND SW OK ZONES BY AROUND 10Z TO 12Z. THEREFORE..INTRODUCED MENTION OF DRIZZLE IN WX GRIDS. OTHERWISE...ONLY MADE MINOR TWEAKS TO HOURLY TEMPS/DEWPOINTS/WINDS TO REFLECT RECENT TRENDS. EXPECT MOISTURE TO CONTINUE TO RETURN NWD...MAKING FOR A VERY CLOUDY DAY TOMORROW. INTERMITTENT SHOWERS WILL BE LIKELY BEGINNING AROUND MIDDAY TOMORROW...LASTING INTO THE EVENING BEFORE A LINE OF STORMS MOVES ACROSS THE AREA. PREV DISCUSSION... /ISSUED 646 PM CST FRI FEB 8 2013/ AVIATION... LOW CEILINGS ARE EXPECTED EARLY SATURDAY WHEN SOUTH WINDS INCREASE AND BRING MOISTURE NORTH. AREAS OF LIGHT RAIN ARE POSSIBLE SATURDAY AFTERNOON BEFORE THUNDERSTORMS IN THE EVENING WITH THE PASSAGE OF A DRYLINE FROM THE WEST. PREV DISCUSSION... /ISSUED 221 PM CST FRI FEB 8 2013/ DISCUSSION... WITH WINDS SHIFTING TO THE SOUTH AND SOUTHEAST MOISTURE WILL BEGIN TO MOVE BACK INTO THE AREA TONIGHT/SATURDAY AHEAD OF A STORM SYSTEM CURRENTLY OVER THE WESTERN U.S. THE UPPER LOW WILL MOVE ACROSS THE SOUTHERN AND CENTRAL ROCKIES INTO THE CENTRAL PLAINS THIS WEEKEND CAUSING SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE AREA STARTING SATURDAY AND CONTINUING THROUGH SUNDAY MORNING. THE MOST LIKELY TIME WILL BE SATURDAY EVENING INTO SUNDAY MORNING. A DRYLINE/PACIFIC COLD FRONT WILL MOVE ACROSS THE REGION DURING THIS TIME PERIOD BRINGING DRIER AIR TO THE REGION. SOME OF THE STORMS COULD BECOME SEVERE WITH LARGE HAIL AND STRONG WINDS THE MAIN CONCERN. IN ADDITION TO THE SHOWERS/STORMS THIS WEEKEND... STRONG WINDS ARE EXPECTED TO DEVELOP SATURDAY AS THE PRESSURE GRADIENT STRENGTHENS. WIND SPEEDS IN SOME AREAS MAY APPROACH WIND ADVISORY CRITERIA. HOWEVER... CURRENT THOUGHTS ARE THAT WINDS WILL REMAIN JUST BELOW CRITERIA SO WILL HOLD OFF ON ANY WIND ADVISORY FOR NOW AND LET LATER SHIFTS EVALUATE. THEN ON SUNDAY... WITH THE DRIER AIR MOVING INTO THE REGION... WILDFIRE POTENTIAL WILL BE VERY HIGH BUT IS EXPECTED TO REMAIN BELOW RED FLAG CRITERIA. AFTER THE WEEKEND... MODELS SHOW ANOTHER STORM SYSTEM AFFECTING THE AREA EARLY NEXT WEEK. LIGHT RAIN AND SNOW WILL BE POSSIBLE WITH THIS SYSTEM MONDAY NIGHT THROUGH TUESDAY NIGHT. MODELS THEN SHOW A THIRD SYSTEM COULD AFFECT THE REGION LATE NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 37 54 46 63 / 10 40 80 10 HOBART OK 36 56 40 63 / 10 50 60 10 WICHITA FALLS TX 39 60 45 66 / 10 50 80 10 GAGE OK 31 55 34 57 / 10 50 50 0 PONCA CITY OK 33 55 44 61 / 10 40 70 10 DURANT OK 39 59 53 70 / 10 40 90 40 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 09/84/84
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1050 PM EST SUN FEB 10 2013 .SYNOPSIS... A FRONTAL SYSTEM WILL BRING A PERIOD OF LIGHT RAIN AND FREEZING RAIN TO THE AREA LATE TONIGHT INTO MONDAY. BRISK AND COLDER CONDITIONS WILL DEVELOP LATER TUESDAY...FOLLOWED BY HIGH PRESSURE TUESDAY NIGHT. LOW PRESSURE OVER THE GULF COAST IS EXPECTED TO TRACK TOWARD THE CAROLINAS ON WEDNESDAY...BEFORE MOVING OFF THE SOUTHERN MID-ATLANTIC COAST WEDNESDAY NIGHT. IT MAY GET CLOSE ENOUGH TO AFFECT SOUTHERN PENNSYLVANIA. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... EVENING SATL LOOP SHOWING UPPER LOW LIFTING NE INTO S MINNESOTA. ASSOCIATED LL JET AND PLUME OF MOISTURE AHEAD OF THIS FEATURE CAN BE TRACED ALL THE WAY BACK TO THE EASTERN PACIFIC. ALTHOUGH PWATS ALONG THIS LL JET ARE 2-3 STD ABV NORMAL...IT SHOULD PASS RATHER QUICKLY THRU CENTRAL PA LATE TONIGHT AND EARLY MON AM. THEREFORE... PRECIP AMTS NOT EXPECTED TO BE HEAVY. 18Z GEFS MEAN QPF RANGES FROM ARND A QUARTER INCH ACROSS THE NORTH CENTRAL MTNS...TO ALMOST 0.75 INCHES ACROSS LANCASTER CO. ALTHOUGH SURGE OF WARM AIR ALOFT ASSOC WITH LL JET SHOULD ENSURE LIQUID PRECIP...MDL SOUNDINGS CONTINUE TO INDICATE ENOUGH COLD AIR NR GROUND LVL FOR A PERIOD OF FZRA. 00Z PIT SOUNDING SHOWS PLENTY OF DRY AIR IN THE LOW LVLS. SO EVEN THOUGH TEMPS ARE CURRENTLY ABV FREEZING OVR MOST OF CENTRAL PA UNDER WAA AND OVERCAST SKIES...EXPECT EVAPORATIVE COOLING TO LOWER SFC TEMPS JUST BLW 0C AS RAIN ARRIVES OVERNIGHT. REGIONAL RADAR AND LATEST RAP INDICATE FZRA/RA WILL OVERSPREAD THE W MTNS ARND MIDNIGHT...THEN SPREAD INTO THE SUSQ VALLEY BY 3 OR 4 AM. SREF/GEFS AND 18Z OPER RUNS ALL POINT TOWARD A MARGINAL ICING EVENT...WITH TEMPS VERY CLOSE TO FREEZING OVERNIGHT...THEN RISING BY DAWN. BY 12Z...BULK OF MDL DATA INDICATES ONLY THE HIGH TERRAIN OF NORTH CENTRAL PA WILL REMAIN BLW FREEZING. SO...I ENVISION WE WILL BE ABLE TO CHIP AWAY AT THE ADVISORY FROM SW TO NE DURING THE EARLY AM HOURS. GIVEN THE MARGINAL TEMPS...EXPECT ICE ACCRETION RATES TO BE LOW AND NOT APPROACH THE LIQUID PRECIP FORECAST MENTIONED ABOVE. ICE AMOUNTS SHOULD RANGE FROM A TRACE TO A TENTH OF AN INCH...WITH THE LEAST AMTS WEST OF THE ALLEGHENIES ARND CONFLUENCE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... SHORT RANGE OPERATIONAL MODELS ARE PRETTY AGREEABLE WITH THE LL JET AND PLUME OF ANOMALOUS PWATS SWEEPING EAST OF THE AREA BTWN 12Z-15Z...CAUSING RA/FZRA TO TAPER OFF. ANY ZR ONGOING AFTER 6AM SHOULD QUICKLY CHANGE TO PLAIN RAIN AS TEMPS RISE INTO THE LOW TO MID 30S BY MID MORNING. THE DRY SLOT SOUTH OF UPPER LOW SHOULD WORK INTO CENTRAL PA BY LATE AM...SHUTTING THE PRECIP OFF AND BRINGING PARTIAL CLEARING...ESP DOWNWIND /EAST/ OF THE ALLEGHENIES. MDL DATA INDICATES MUCH OF CENTRAL PA WILL BRIEFLY BREAK INTO THE WARM SECTOR MON AFTN WITH GEFS 925 TEMPS SUPPORTIVE OF HIGHS AOA 50F ACROSS SOUTHERN PA. BY LATE IN THE DAY...SFC COLD FRONT WILL PUSH INTO WESTERN PA... ACCOMPANIED BY SCT -SHRA/SN AND A GUSTY WIND SHIFT FROM SW TO WEST. DON/T EXPECT ANY SNOW ACCUMS...AS SFC TEMPS SHOULD REMAIN WELL ABV FREEZING THRU EARLY EVENING...EVEN OVR THE NW MTNS. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... A FAIRLY AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. NUMEROUS NORTHERN AND SOUTHERN STREAM SHORTWAVES WILL BRING SEVERAL CHANCES FOR PCPN TOWARD PA DURING THE PERIOD... THOUGH AT THIS POINT IN TIME SIGNIFICANT PCPN EVENTS DO NOT APPEAR DESTINED FOR THE COMMONWEALTH...AT LEAST NOT DIRECTLY. AN ABUNDANCE OF SRN STREAM FLOW WILL BRING INTRUSIONS OF ABOVE FREEZING TEMPERATURES TO THE REGION...FURTHER COMPLICATING THE LONG TERM FORECAST DETAILS. PHASING ENERGY MAY SUPPORT A NEARLY FULL LATITUDE TROF SPREADING EASTWARD INTO THE EASTERN U.S. BY NEXT WEEKEND...LEADING TO PERHAPS THE HIGHEST POTENTIAL OF SIGNIFICANT PCPN POTENTIAL IN THE LONG TERM PERIOD. LAKE EFFECT SHOWERS WILL BE ONGOING IN THE WEAK OF MONDAYS SYSTEM/COLD FROPA. A WEAK RIDGE OF HIGH PRESSURE SLIDES NE ACROSS THE STATE TUESDAY NIGHT BRINGING AN END TO THE SNOW SHOWERS. THE NEXT SYSTEM HEADED OUR WAY FOR WEDNESDAY AFTERNOON INTO EARLY THURSDAY IS TIED TO A RATHER VIGOROUS SOUTHERN STREAM JET EXIT REGION. THE NOSE OF THIS 140 KT JET WILL LIFT TWD THE CENTRAL APPALACHIANS DURING THE DAY WEDNESDAY. DETAILS OF THE EXACT PRESSURE PATTERN AND TIMING OF A WEAK SFC LOW WEST OF THE APPALACHIANS PER THE 06Z NAM /AND SECONDARY DEVELOPMENT NEAR THE VA COAST/ ARE STILL A BIT SKETCHY. LATEST...00Z GEFS IS A BIT OMINOUS AS ABOUT 20-25 PERCENT OF ITS MEMBERS CONTAIN AROUND AN INCH OF QPF IN THE FORM OF SNOW LATE WEDNESDAY INTO THURSDAY. SOME VARIATIONS IN THE TIMING OF THIS PRECIP ARE ALSO NOTED. MEAN TRACK OF THE 850 MB LOW CENTER ON THE GEFS TAKES IT ACROSS ERN VA AND SOUTHERN DELAWARE ALONG WITH A SLIGHTLY ANOMALOUS EASTERLY WIND AT THAT PRESSURE LEVEL. THE GEFS CONSENSUS QPF IS AROUND 0.25 INCH FOR THE LOWER SUSQ VALLEY WITH SHARPLY LESSER AMOUNTS TO THE NW. PAINTED HIGH CHC TO LOW LIKELY POPS INTO OUR GRIDDED DATABASE FOR THE SE THIRD TO HALF OF THE CWA...CENTERED ON WED NIGHT WITH A RESULTANT 1-3 INCHES OF SNOW. THIS SYSTEM BEARS CLOSE WATCHING AS ANY INTERACTION WITH AN UPSTREAM WAVE IN THE NRN BRANCH COULD HELP TO INVIGORATE THE COASTAL LOW AND LLVL EASTERLY FLOW BRINGING MORE SNOW TO THE SERN ZONES...AND SPREADING LIGHT SNOWS OVER THE I-80 CORRIDOR. ITS CURIOUS TO NOTE THAT THE 00Z OPERATIONAL EC /THAT INITIALLY HANDLED THE RECENT NEW ENGLAND BLIZZARD MUCH BETTER THAN THE U.S MODELS/ IS 12-18 HOURS FASTER...AND A FEW HUNDRED KM FURTHER SOUTH WITH THE SFC/UPPER WAVE TRACK...AND JUST BRUSHES THE MASON/DIXON LINE WITH SOME LIGHT SNOW AT THE NRN EDGE OF THE PRECIP SHIELD. THE AFOREMENTIONED BROAD LONGWAVE TROF MOVED ACROSS THE REGION THURSDAY INTO NEXT WEEKEND...WITH A RETURN OF ARCTIC AIR. WITH THE TROF WILL BE SIGNIFICANT NRN STREAM ENERGY AND AT LEAST ONE CLIPPER SYSTEMS MOVING ACROSS NW PA ON FRIDAY WITH LE SNOW SHOWERS PERSISTING INTO NEXT WEEKEND. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... NO MAJOR CHANGES TO 03Z TAFS. 03Z TAFS SENT. THINGS RUNNING SLOW...SOME COMPUTER ISSUES. VERY FEW CHANGES MADE TO 00Z PACKAGE...MAIN THING WAS TO ADD SOME GROUPS FOR THE LATER PART OF MONDAY. STARTING TO SEE SOME RETURNS ON THE RADAR...BUT TIMING STILL LOOKS GOOD. NAM MODEL SLOWER THAN THE GFS...WHICH HAS BEEN THE CASE. CURRENT FCST WEIGHTED TO THE FASTER ONSET OF RAIN ETC. WILL CONTINUE TO MONITOR AND UPDATE AS NEEDED...AND AT 1030 PM. HIGH PRESSURE HAS PROVIDED FOR A VERY NICE DAY FOR FLYING WITH JUST SOME HIGH CLOUDS AND LIGHT WINDS. CONDITIONS WILL DETERIORATE OVERNIGHT AS A FRONTAL SYSTEM APPROACHES. ICING PROBLEMS CAN BE EXPECTED ALONG WITH MVFR/IFR CLOUDS/VIZ AS RAIN MOVES INTO SURFACE TEMPS THAT INITIALLY WILL BE AT OR BELOW FREEZING. THESE ICING CONDITIONS WILL LAST THROUGH SUNRISE OVER CENTRAL AND NORTHERN AREAS BEFORE CHANGING TO PLAIN RAIN EVERYWHERE. OTHERWISE THE LOW CLOUDS AND VISIBILITIES WITH THE STEADY RAINS WILL BEGIN TO IMPROVE AS THE DAY WEARS ON AND THE STEADY RAIN GIVES WAY TO SCATTERED SHOWERS WITH THE PASSAGE OF A COLD FRONT. EXPECT THE BEST CONDITIONS TO DEVELOP BY EARLY TO MID AFTERNOON OVER THE WEST WITH SOME DRIER AIR RIGHT BEHIND THE COLD FRONT. TERMINALS OVER THE SUSQ VALLEY WILL LIKELY REMAIN MVFR/IFR WELL INTO THE DAY BEFORE THE DRIER AIR CAN BRING IMPROVEMENT. MONDAY NIGHT LOWER CEILINGS WILL REDEVELOP OVER THE WESTERN HIGH TERRAIN AS COLD AIR MOVES OVER THE GREAT LAKES AND REINTRODUCES THE USUAL POST COLD FRONTAL FLOW PATTERN WE GENERALLY EXPECT IN THE WINTER...WITH MVFR/IFR CLOUDS AND VIS WITH SCATTERED SNOW SHOWERS. OUTLOOK... TUE...MVFR CIGS NORTH/WEST. VFR EAST. WED...DEVELOPING VFR TO START THE DAY. LOWER CONDITIONS POSSIBLE OVER THE SOUTH BY LATE DAY AS A STORM SYSTEM SKIRTS THE REGION. THUR...MAINLY VFR. FRI...MVFR/IFR DEVELOPING OVER THE WEST AND CENTRAL TERMINALS. VFR EAST. WINDY OUT OF THE NW. && .CTP WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR PAZ004>006- 010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
927 PM EST SUN FEB 10 2013 .SYNOPSIS... A FRONTAL SYSTEM WILL BRING A PERIOD OF LIGHT RAIN AND FREEZING RAIN TO THE AREA LATE TONIGHT INTO MONDAY. BRISK AND COLDER CONDITIONS WILL DEVELOP LATER TUESDAY...FOLLOWED BY HIGH PRESSURE TUESDAY NIGHT. LOW PRESSURE OVER THE GULF COAST IS EXPECTED TO TRACK TOWARD THE CAROLINAS ON WEDNESDAY...BEFORE MOVING OFF THE SOUTHERN MID-ATLANTIC COAST WEDNESDAY NIGHT. IT MAY GET CLOSE ENOUGH TO AFFECT SOUTHERN PENNSYLVANIA. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... EVENING SATL LOOP SHOWING UPPER LOW LIFTING NE INTO S MINNESOTA. ASSOCIATED LL JET AND PLUME OF MOISTURE AHEAD OF THIS FEATURE CAN BE TRACED ALL THE WAY BACK TO THE EASTERN PACIFIC. ALTHOUGH PWATS ALONG THIS LL JET ARE 2-3 STD ABV NORMAL...IT SHOULD PASS RATHER QUICKLY THRU CENTRAL PA LATE TONIGHT AND EARLY MON AM. THEREFORE... PRECIP AMTS NOT EXPECTED TO BE HEAVY. 18Z GEFS MEAN QPF RANGES FROM ARND A QUARTER INCH ACROSS THE NORTH CENTRAL MTNS...TO ALMOST 0.75 INCHES ACROSS LANCASTER CO. ALTHOUGH SURGE OF WARM AIR ALOFT ASSOC WITH LL JET SHOULD ENSURE LIQUID PRECIP...MDL SOUNDINGS CONTINUE TO INDICATE ENOUGH COLD AIR NR GROUND LVL FOR A PERIOD OF FZRA. 00Z PIT SOUNDING SHOWS PLENTY OF DRY AIR IN THE LOW LVLS. SO EVEN THOUGH TEMPS ARE CURRENTLY ABV FREEZING OVR MOST OF CENTRAL PA UNDER WAA AND OVERCAST SKIES...EXPECT EVAPORATIVE COOLING TO LOWER SFC TEMPS JUST BLW 0C AS RAIN ARRIVES OVERNIGHT. REGIONAL RADAR AND LATEST RAP INDICATE FZRA/RA WILL OVERSPREAD THE W MTNS ARND MIDNIGHT...THEN SPREAD INTO THE SUSQ VALLEY BY 3 OR 4 AM. SREF/GEFS AND 18Z OPER RUNS ALL POINT TOWARD A MARGINAL ICING EVENT...WITH TEMPS VERY CLOSE TO FREEZING OVERNIGHT...THEN RISING BY DAWN. BY 12Z...BULK OF MDL DATA INDICATES ONLY THE HIGH TERRAIN OF NORTH CENTRAL PA WILL REMAIN BLW FREEZING. SO...I ENVISION WE WILL BE ABLE TO CHIP AWAY AT THE ADVISORY FROM SW TO NE DURING THE EARLY AM HOURS. GIVEN THE MARGINAL TEMPS...EXPECT ICE ACCRETION RATES TO BE LOW AND NOT APPROACH THE LIQUID PRECIP FORECAST MENTIONED ABOVE. ICE AMOUNTS SHOULD RANGE FROM A TRACE TO A TENTH OF AN INCH...WITH THE LEAST AMTS WEST OF THE ALLEGHENIES ARND CONFLUENCE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... SHORT RANGE OPERATIONAL MODELS ARE PRETTY AGREEABLE WITH THE LL JET AND PLUME OF ANOMALOUS PWATS SWEEPING EAST OF THE AREA BTWN 12Z-15Z...CAUSING RA/FZRA TO TAPER OFF. ANY ZR ONGOING AFTER 6AM SHOULD QUICKLY CHANGE TO PLAIN RAIN AS TEMPS RISE INTO THE LOW TO MID 30S BY MID MORNING. THE DRY SLOT SOUTH OF UPPER LOW SHOULD WORK INTO CENTRAL PA BY LATE AM...SHUTTING THE PRECIP OFF AND BRINGING PARTIAL CLEARING...ESP DOWNWIND /EAST/ OF THE ALLEGHENIES. MDL DATA INDICATES MUCH OF CENTRAL PA WILL BRIEFLY BREAK INTO THE WARM SECTOR MON AFTN WITH GEFS 925 TEMPS SUPPORTIVE OF HIGHS AOA 50F ACROSS SOUTHERN PA. BY LATE IN THE DAY...SFC COLD FRONT WILL PUSH INTO WESTERN PA... ACCOMPANIED BY SCT -SHRA/SN AND A GUSTY WIND SHIFT FROM SW TO WEST. DON/T EXPECT ANY SNOW ACCUMS...AS SFC TEMPS SHOULD REMAIN WELL ABV FREEZING THRU EARLY EVENING...EVEN OVR THE NW MTNS. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... A FAIRLY AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. NUMEROUS NORTHERN AND SOUTHERN STREAM SHORTWAVES WILL BRING SEVERAL CHANCES FOR PCPN TOWARD PA DURING THE PERIOD... THOUGH AT THIS POINT IN TIME SIGNIFICANT PCPN EVENTS DO NOT APPEAR DESTINED FOR THE COMMONWEALTH...AT LEAST NOT DIRECTLY. AN ABUNDANCE OF SRN STREAM FLOW WILL BRING INTRUSIONS OF ABOVE FREEZING TEMPERATURES TO THE REGION...FURTHER COMPLICATING THE LONG TERM FORECAST DETAILS. PHASING ENERGY MAY SUPPORT A NEARLY FULL LATITUDE TROF SPREADING EASTWARD INTO THE EASTERN U.S. BY NEXT WEEKEND...LEADING TO PERHAPS THE HIGHEST POTENTIAL OF SIGNIFICANT PCPN POTENTIAL IN THE LONG TERM PERIOD. LAKE EFFECT SHOWERS WILL BE ONGOING IN THE WEAK OF MONDAYS SYSTEM/COLD FROPA. A WEAK RIDGE OF HIGH PRESSURE SLIDES NE ACROSS THE STATE TUESDAY NIGHT BRINGING AN END TO THE SNOW SHOWERS. THE NEXT SYSTEM HEADED OUR WAY FOR WEDNESDAY AFTERNOON INTO EARLY THURSDAY IS TIED TO A RATHER VIGOROUS SOUTHERN STREAM JET EXIT REGION. THE NOSE OF THIS 140 KT JET WILL LIFT TWD THE CENTRAL APPALACHIANS DURING THE DAY WEDNESDAY. DETAILS OF THE EXACT PRESSURE PATTERN AND TIMING OF A WEAK SFC LOW WEST OF THE APPALACHIANS PER THE 06Z NAM /AND SECONDARY DEVELOPMENT NEAR THE VA COAST/ ARE STILL A BIT SKETCHY. LATEST...00Z GEFS IS A BIT OMINOUS AS ABOUT 20-25 PERCENT OF ITS MEMBERS CONTAIN AROUND AN INCH OF QPF IN THE FORM OF SNOW LATE WEDNESDAY INTO THURSDAY. SOME VARIATIONS IN THE TIMING OF THIS PRECIP ARE ALSO NOTED. MEAN TRACK OF THE 850 MB LOW CENTER ON THE GEFS TAKES IT ACROSS ERN VA AND SOUTHERN DELAWARE ALONG WITH A SLIGHTLY ANOMALOUS EASTERLY WIND AT THAT PRESSURE LEVEL. THE GEFS CONSENSUS QPF IS AROUND 0.25 INCH FOR THE LOWER SUSQ VALLEY WITH SHARPLY LESSER AMOUNTS TO THE NW. PAINTED HIGH CHC TO LOW LIKELY POPS INTO OUR GRIDDED DATABASE FOR THE SE THIRD TO HALF OF THE CWA...CENTERED ON WED NIGHT WITH A RESULTANT 1-3 INCHES OF SNOW. THIS SYSTEM BEARS CLOSE WATCHING AS ANY INTERACTION WITH AN UPSTREAM WAVE IN THE NRN BRANCH COULD HELP TO INVIGORATE THE COASTAL LOW AND LLVL EASTERLY FLOW BRINGING MORE SNOW TO THE SERN ZONES...AND SPREADING LIGHT SNOWS OVER THE I-80 CORRIDOR. ITS CURIOUS TO NOTE THAT THE 00Z OPERATIONAL EC /THAT INITIALLY HANDLED THE RECENT NEW ENGLAND BLIZZARD MUCH BETTER THAN THE U.S MODELS/ IS 12-18 HOURS FASTER...AND A FEW HUNDRED KM FURTHER SOUTH WITH THE SFC/UPPER WAVE TRACK...AND JUST BRUSHES THE MASON/DIXON LINE WITH SOME LIGHT SNOW AT THE NRN EDGE OF THE PRECIP SHIELD. THE AFOREMENTIONED BROAD LONGWAVE TROF MOVED ACROSS THE REGION THURSDAY INTO NEXT WEEKEND...WITH A RETURN OF ARCTIC AIR. WITH THE TROF WILL BE SIGNIFICANT NRN STREAM ENERGY AND AT LEAST ONE CLIPPER SYSTEMS MOVING ACROSS NW PA ON FRIDAY WITH LE SNOW SHOWERS PERSISTING INTO NEXT WEEKEND. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... VERY FEW CHANGES MADE TO 00Z PACKAGE...MAIN THING WAS TO ADD SOME GROUPS FOR THE LATER PART OF MONDAY. STARTING TO SEE SOME RETURNS ON THE RADAR...BUT TIMING STILL LOOKS GOOD. NAM MODEL SLOWER THAN THE GFS...WHICH HAS BEEN THE CASE. CURRENT FCST WEIGHTED TO THE FASTER ONSET OF RAIN ETC. WILL CONTINUE TO MONITOR AND UPDATE AS NEEDED...AND AT 1030 PM. HIGH PRESSURE HAS PROVIDED FOR A VERY NICE DAY FOR FLYING WITH JUST SOME HIGH CLOUDS AND LIGHT WINDS. CONDITIONS WILL DETERIORATE OVERNIGHT AS A FRONTAL SYSTEM APPROACHES. ICING PROBLEMS CAN BE EXPECTED ALONG WITH MVFR/IFR CLOUDS/VIZ AS RAIN MOVES INTO SURFACE TEMPS THAT INITIALLY WILL BE AT OR BELOW FREEZING. THESE ICING CONDITIONS WILL LAST THROUGH SUNRISE OVER CENTRAL AND NORTHERN AREAS BEFORE CHANGING TO PLAIN RAIN EVERYWHERE. OTHERWISE THE LOW CLOUDS AND VISIBILITIES WITH THE STEADY RAINS WILL BEGIN TO IMPROVE AS THE DAY WEARS ON AND THE STEADY RAIN GIVES WAY TO SCATTERED SHOWERS WITH THE PASSAGE OF A COLD FRONT. EXPECT THE BEST CONDITIONS TO DEVELOP BY EARLY TO MID AFTERNOON OVER THE WEST WITH SOME DRIER AIR RIGHT BEHIND THE COLD FRONT. TERMINALS OVER THE SUSQ VALLEY WILL LIKELY REMAIN MVFR/IFR WELL INTO THE DAY BEFORE THE DRIER AIR CAN BRING IMPROVEMENT. MONDAY NIGHT LOWER CEILINGS WILL REDEVELOP OVER THE WESTERN HIGH TERRAIN AS COLD AIR MOVES OVER THE GREAT LAKES AND REINTRODUCES THE USUAL POST COLD FRONTAL FLOW PATTERN WE GENERALLY EXPECT IN THE WINTER...WITH MVFR/IFR CLOUDS AND VIS WITH SCATTERED SNOW SHOWERS. OUTLOOK... TUE...MVFR CIGS NORTH/WEST. VFR EAST. WED...DEVELOPING VFR TO START THE DAY. LOWER CONDITIONS POSSIBLE OVER THE SOUTH BY LATE DAY AS A STORM SYSTEM SKIRTS THE REGION. THUR...MAINLY VFR. FRI...MVFR/IFR DEVELOPING OVER THE WEST AND CENTRAL TERMINALS. VFR EAST. WINDY OUT OF THE NW. && .CTP WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR PAZ004>006- 010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
855 PM EST SUN FEB 10 2013 .SYNOPSIS... A FRONTAL SYSTEM WILL BRING A PERIOD OF LIGHT RAIN AND FREEZING RAIN TO THE AREA LATE TONIGHT INTO MONDAY. BRISK AND COLDER CONDITIONS WILL DEVELOP LATER TUESDAY...FOLLOWED BY HIGH PRESSURE TUESDAY NIGHT. LOW PRESSURE OVER THE GULF COAST IS EXPECTED TO TRACK TOWARD THE CAROLINAS ON WEDNESDAY...BEFORE MOVING OFF THE SOUTHERN MID-ATLANTIC COAST WEDNESDAY NIGHT. IT MAY GET CLOSE ENOUGH TO AFFECT SOUTHERN PENNSYLVANIA. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... EVENING SATL LOOP SHOWING UPPER LOW LIFTING NE INTO S MINNESOTA. ASSOCIATED LL JET AND PLUME OF MOISTURE AHEAD OF THIS FEATURE CAN BE TRACED ALL THE WAY BACK TO THE EASTERN PACIFIC. ALTHOUGH PWATS ALONG THIS LL JET ARE 2-3 STD ABV NORMAL...IT SHOULD PASS RATHER QUICKLY THRU CENTRAL PA LATE TONIGHT AND EARLY MON AM. THEREFORE...PRECIP AMTS NOT EXPECTED TO BE HEAVY. 18Z GEFS MEAN QPF RANGES FROM ARND A QUARTER INCH ACROSS THE NORTH CENTRAL MTNS...TO ALMOST 0.75 INCHES ACROSS LANCASTER CO. ALTHOUGH SURGE OF WARM AIR ALOFT ASSOC WITH LL JET SHOULD ENSURE LIQUID PRECIP...MDL SOUNDINGS CONTINUE TO INDICATE ENOUGH COLD AIR NR GROUND LVL FOR A PERIOD OF FZRA. 00Z PIT SOUNDING SHOWS PLENTY OF DRY AIR IN THE LOW LVLS. SO EVEN THOUGH TEMPS ARE CURRENTLY ABV FREEZING OVR MOST OF CENTRAL PA UNDER WAA AND OVERCAST SKIES...EXPECT EVAPORATIVE COOLING TO LOWER SFC TEMPS JUST BLW 0C AS RAIN ARRIVES OVERNIGHT. REGIONAL RADAR AND LATEST RAP INDICATE FZRA/RA WILL OVERSPREAD THE W MTNS ARND MIDNIGHT...THEN SPREAD INTO THE SUSQ VALLEY BY 3 OR 4 AM. SREF/GEFS AND 18Z OPER RUNS ALL POINT TOWARD A MARGINAL ICING EVENT...WITH TEMPS VERY CLOSE TO FREEZING OVERNIGHT...THEN RISING BY DAWN. BY 12Z...BULK OF MDL DATA INDICATES ONLY THE HIGH TERRAIN OF NORTH CENTRAL PA WILL REMAIN BLW FREEZING. SO...I ENVISION WE WILL BE ABLE TO CHIP AWAY AT THE ADVISORY FROM SW TO NE DURING THE EARLY AM HOURS. GIVEN THE MARGINAL TEMPS...EXPECT ICE ACCRETION RATES TO BE LOW AND NOT APPROACH THE LIQUID PRECIP FORECAST MENTIONED ABOVE. ICE AMOUNTS SHOULD RANGE FROM A TRACE TO A TENTH OF AN INCH...WITH THE LEAST AMTS WEST OF THE ALLEGHENIES ARND CONFLUENCE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... SHORT RANGE OPERATIONAL MODELS ARE PRETTY AGREEABLE WITH THE LL JET AND PLUME OF ANOMALOUS PWATS SWEEPING EAST OF THE AREA BTWN 12Z-15Z...CAUSING RA/FZRA TO TAPER OFF. ANY ZR ONGOING AFTER 6AM SHOULD QUICKLY CHANGE TO PLAIN RAIN AS TEMPS RISE INTO THE LOW TO MID 30S BY MID MORNING. THE DRY SLOT SOUTH OF UPPER LOW SHOULD WORK INTO CENTRAL PA BY LATE AM...SHUTTING THE PRECIP OFF AND BRINGING PARTIAL CLEARING...ESP DOWNWIND /EAST/ OF THE ALLEGHENIES. MDL DATA INDICATES MUCH OF CENTRAL PA WILL BRIEFLY BREAK INTO THE WARM SECTOR MON AFTN WITH GEFS 925 TEMPS SUPPORTIVE OF HIGHS AOA 50F ACROSS SOUTHERN PA. BY LATE IN THE DAY...SFC COLD FRONT WILL PUSH INTO WESTERN PA...ACCOMPANIED BY SCT -SHRA/SN AND A GUSTY WIND SHIFT FROM SW TO WEST. DON/T EXPECT ANY SNOW ACCUMS...AS SFC TEMPS SHOULD REMAIN WELL ABV FREEZING THRU EARLY EVENING...EVEN OVR THE NW MTNS. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... A FAIRLY AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. NUMEROUS NORTHERN AND SOUTHERN STREAM SHORTWAVES WILL BRING SEVERAL CHANCES FOR PCPN TOWARD PA DURING THE PERIOD... THOUGH AT THIS POINT IN TIME SIGNIFICANT PCPN EVENTS DO NOT APPEAR DESTINED FOR THE COMMONWEALTH...AT LEAST NOT DIRECTLY. AN ABUNDANCE OF SRN STREAM FLOW WILL BRING INTRUSIONS OF ABOVE FREEZING TEMPERATURES TO THE REGION...FURTHER COMPLICATING THE LONG TERM FORECAST DETAILS. PHASING ENERGY MAY SUPPORT A NEARLY FULL LATITUDE TROF SPREADING EASTWARD INTO THE EASTERN U.S. BY NEXT WEEKEND...LEADING TO PERHAPS THE HIGHEST POTENTIAL OF SIGNIFICANT PCPN POTENTIAL IN THE LONG TERM PERIOD. LAKE EFFECT SHOWERS WILL BE ONGOING IN THE WEAK OF MONDAYS SYSTEM/COLD FROPA. A WEAK RIDGE OF HIGH PRESSURE SLIDES NE ACROSS THE STATE TUESDAY NIGHT BRINGING AN END TO THE SNOW SHOWERS. THE NEXT SYSTEM HEADED OUR WAY FOR WEDNESDAY AFTERNOON INTO EARLY THURSDAY IS TIED TO A RATHER VIGOROUS SOUTHERN STREAM JET EXIT REGION. THE NOSE OF THIS 140 KT JET WILL LIFT TWD THE CENTRAL APPALACHIANS DURING THE DAY WEDNESDAY. DETAILS OF THE EXACT PRESSURE PATTERN AND TIMING OF A WEAK SFC LOW WEST OF THE APPALACHIANS PER THE 06Z NAM /AND SECONDARY DEVELOPMENT NEAR THE VA COAST/ ARE STILL A BIT SKETCHY. LATEST...00Z GEFS IS A BIT OMINOUS AS ABOUT 20-25 PERCENT OF ITS MEMBERS CONTAIN AROUND AN INCH OF QPF IN THE FORM OF SNOW LATE WEDNESDAY INTO THURSDAY. SOME VARIATIONS IN THE TIMING OF THIS PRECIP ARE ALSO NOTED. MEAN TRACK OF THE 850 MB LOW CENTER ON THE GEFS TAKES IT ACROSS ERN VA AND SOUTHERN DELAWARE ALONG WITH A SLIGHTLY ANOMALOUS EASTERLY WIND AT THAT PRESSURE LEVEL. THE GEFS CONSENSUS QPF IS AROUND 0.25 INCH FOR THE LOWER SUSQ VALLEY WITH SHARPLY LESSER AMOUNTS TO THE NW. PAINTED HIGH CHC TO LOW LIKELY POPS INTO OUR GRIDDED DATABASE FOR THE SE THIRD TO HALF OF THE CWA...CENTERED ON WED NIGHT WITH A RESULTANT 1-3 INCHES OF SNOW. THIS SYSTEM BEARS CLOSE WATCHING AS ANY INTERACTION WITH AN UPSTREAM WAVE IN THE NRN BRANCH COULD HELP TO INVIGORATE THE COASTAL LOW AND LLVL EASTERLY FLOW BRINGING MORE SNOW TO THE SERN ZONES...AND SPREADING LIGHT SNOWS OVER THE I-80 CORRIDOR. ITS CURIOUS TO NOTE THAT THE 00Z OPERATIONAL EC /THAT INITIALLY HANDLED THE RECENT NEW ENGLAND BLIZZARD MUCH BETTER THAN THE U.S MODELS/ IS 12-18 HOURS FASTER...AND A FEW HUNDRED KM FURTHER SOUTH WITH THE SFC/UPPER WAVE TRACK...AND JUST BRUSHES THE MASON/DIXON LINE WITH SOME LIGHT SNOW AT THE NRN EDGE OF THE PRECIP SHIELD. THE AFOREMENTIONED BROAD LONGWAVE TROF MOVED ACROSS THE REGION THURSDAY INTO NEXT WEEKEND...WITH A RETURN OF ARCTIC AIR. WITH THE TROF WILL BE SIGNIFICANT NRN STREAM ENERGY AND AT LEAST ONE CLIPPER SYSTEMS MOVING ACROSS NW PA ON FRIDAY WITH LE SNOW SHOWERS PERSISTING INTO NEXT WEEKEND. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... MINOR ADJUSTMENTS MADE TO WINDS IN THE 21Z TAFS. EARLIER DISCUSSION BELOW. HIGH PRESSURE HAS PROVIDED FOR A VERY NICE DAY FOR FLYING WITH JUST SOME HIGH CLOUDS AND LIGHT WINDS. CONDITIONS WILL DETERIORATE OVERNIGHT AS A FRONTAL SYSTEM APPROACHES. ICING PROBLEMS CAN BE EXPECTED ALONG WITH MVFR/IFR CLOUDS/VIZ AS RAIN MOVES INTO SURFACE TEMPS THAT INITIALLY WILL BE AT OR BELOW FREEZING. THESE ICING CONDITIONS WILL LAST THROUGH SUNRISE OVER CENTRAL AND NORTHERN AREAS BEFORE CHANGING TO PLAIN RAIN EVERYWHERE. OTHERWISE THE LOW CLOUDS AND VISIBILITIES WITH THE STEADY RAINS WILL BEGIN TO IMPROVE AS THE DAY WEARS ON AND THE STEADY RAIN GIVES WAY TO SCATTERED SHOWERS WITH THE PASSAGE OF A COLD FRONT. EXPECT THE BEST CONDITIONS TO DEVELOP BY EARLY TO MID AFTERNOON OVER THE WEST WITH SOME DRIER AIR RIGHT BEHIND THE COLD FRONT. TERMINALS OVER THE SUSQ VALLEY WILL LIKELY REMAIN MVFR/IFR WELL INTO THE DAY BEFORE THE DRIER AIR CAN BRING IMPROVEMENT. MONDAY NIGHT LOWER CEILINGS WILL REDEVELOP OVER THE WESTERN HIGH TERRAIN AS COLD AIR MOVES OVER THE GREAT LAKES AND REINTRODUCES THE USUAL POST COLD FRONTAL FLOW PATTERN WE GENERALLY EXPECT IN THE WINTER...WITH MVFR/IFR CLOUDS AND VIS WITH SCATTERED SNOW SHOWERS. OUTLOOK... TUE...MVFR CIGS NORTH/WEST. VFR EAST. WED...DEVELOPING VFR TO START THE DAY. LOWER CONDITIONS POSSIBLE OVER THE SOUTH BY LATE DAY AS A STORM SYSTEM SKIRTS THE REGION. THUR...MAINLY VFR. FRI...MVFR/IFR DEVELOPING OVER THE WEST AND CENTRAL TERMINALS. VFR EAST. WINDY OUT OF THE NW. && .CTP WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR PAZ004>006- 010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1115 PM CST FRI FEB 8 2013 .DISCUSSION.../ISSUED AT 900 PM CST/ STRATUS IS SPREADING BACK INTO THE FORECAST AREA FROM THE SOUTHEAST AND SHOULD BE COVERING THE NORTHEAST 60-70 PERCENT OF OUR AREA AFTER MIDNIGHT. THE SOUTHWEST CORNER WILL STAY MOSTLY CLEAR FOR A WHILE THEN SHOULD GET SOME INCREASE IN HIGHER CLOUDS. WILL KEEP SOME AREAS OF FOG AS WE HAVE FOR AFTER MIDNIGHT. AT THIS POINT DOES NOT LOOK LIKE IT WILL GET VERY DENSE ANYWHERE IN THE STIFF FLOW...STRATUS WOULD HAVE TO LOWER MORE THAN CURRENTLY EXPECTED TO GET ANYTHING HALFWAY DENSE. MEANWHILE...WINDS ARE BEHAVING AS EXPECTED AND SHOULD BEGIN TO SLOWLY DROP OFF LATER OUT WEST. TEMPERATURES WILL NOT DO MUCH DROPPING SO SHOULD NOT BE MUCH OF A PROBLEM...THOUGH IT IS POSSIBLE THAT THE FAR WEST COULD DROP A LITTLE MORE THAN WE HAVE LATE IF THERE IS NOT MUCH INCREASE IN CLOUDS. && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ MAIN FORECAST CHALLENGE THROUGH THIS TAF PERIOD WILL BE POTENTIAL REDEVELOPMENT OF IFR-LIFR STRATUS TONIGHT...WITH PRECIPITATION ISSUES DEVELOPING LATE IN THE PERIOD. SEEING STRATUS REDEVELOP ACROSS THE EAST...AND WILL EXPECT THIS TO SPREAD BACK INTO AT LEAST THE I-29 CORRIDOR AND POSSIBLY REACH THE JAMES VALLEY THROUGH 12Z. LESS CONFIDENCE IN STRATUS REACHING KHON SO HAVE KEPT THEM LARGELY WITH SCATTERED CLOUDS BELOW 1KFT. POSSIBLE THEY COULD GO BKN-OVC BEFORE DAYBREAK THOUGH...AND WILL MONITOR CLOSELY. THINK WINDS WILL STAY UP ENOUGH THAT VISIBILITY RESTRICTIONS WILL BE LIMITED...THOUGH PATCHY MVFR VISIBILITY IS POSSIBLE. ANY STRATUS/FOG WILL LINGER THROUGH THE LATE MORNING/MIDDAY HOURS SATURDAY...BEFORE STRONGER MIXING AHEAD OF SIGNIFICANT WINTER SYSTEM AIDS IN CLEARING TO VFR CONDITIONS FOR SATURDAY AFTERNOON. WINTER STORM WILL SPREAD PRECIP INTO THE AREA AFTER 00Z...WITH MOST AREAS BEGINNING AS RAIN WITH VFR VISIBILITIES AND MVFR/IFR CEILINGS. KHON COULD SEE CHANGEOVER TO -SN PRIOR TO THE END OF THE PERIOD AND INTRODUCED SOME MVFR VISIBILITY IN -SN THERE AFTER 04Z. MID LEVEL INSTABILITY COULD ALSO LEAD TO ISOLATED TSRA AROUND KSUX/KFSD SATURDAY EVENING. HOWEVER CONFIDENCE IN DEVELOPMENT/COVERAGE IN THUNDER THREAT IS LOW...SO DID NOT INCLUDE MENTION AT THIS TIME. && .PREV DISCUSSION.../ISSUED AT 350 PM CST/ STRATUS FIELD MELTING AWAY ACROSS PORTIONS OF THE FORECAST AREA WHILE IN OTHER AREAS IT IS HOLDING STEADFAST. RAP SUGGESTS THAT STRATUS WILL BECOME MORE WIDESPREAD ACROSS THE AREA THROUGH THE EVENING HOURS...AND EVEN SUGGESTS THE POTENTIAL FOR FOG DEVELOPING ALONG AND EAST OF THE JAMES RIVER VALLEY. HAVE ADDED MENTION OF FOG ALONG AND EAST OF THE JAMES RIVER VALLEY...BUT HAVE NOT GONE AS BULLISH AS HE RAP WHICH WOULD SUGGEST THE POTENTIAL FOR A DENSE FOG ADVISORY. QUESTIONS STILL REMAIN AS TO HOW LONG THE STRATUS WILL LINGER DURING THE DAYLIGHT HOURS ON SATURDAY. OVERALL...SYNOPTIC PATTERN SUGGESTS WARM FRONT APPROACHING FROM THE SOUTH WITH 925 HPA TEMPERATURE WARMING 2-3 DEGREES C IN THE 18 TO 00Z TIME FRAME. THIS SHOULD LEAD TO A FAIR AMOUNT OF LATE DAY HEATING...WITH LATE AFTERNOON/EARLY EVENING HIGHS. HAVE OUTSIDE CHANCE OF A SHOWER DEVELOPING IN THE LATE AFTERNOON HOURS ACROSS CENTRAL SOUTH DAKOTA...BUT MAIN PRECIPITATION SHOULD HOLD OFF THROUGH 00Z SUNDAY. SATURDAY NIGHT WILL START TO BE A TRANSITION PERIOD TO WEATHER ACROSS THE AREA AS STRONG JET STARTS TO LIFT OUT OF THE SOUTHERN ROCKIES AND TOWARD THE CENTRAL PLAINS. LOW LEVEL THERMAL BOUNDARY SHOULD SHARPEN ALONG DEVELOPING INVERTED TROUGH. SURGE OF MOISTURE WILL PUSH INTO THE SYSTEM AS LOW LEVEL JET INCREASES...AND GOOD DYNAMIC NUDGE WILL DEVELOP AS DRY SLOT PUSHES NORTH THROUGH NEBRASKA. AS THIS FIRST LOBE LIFTS NORTHEASTWARD THROUGH THE PLAINS DURING THE EVENING...SOME ELEVATED INSTABILITY INDICATED...AND WHILE SURFACE TEMPS SHOULD BE SAFELY ABOVE FREEZING...MAY END UP WITH SOME ICE PELLETS WITH SHOWERY PRECIPITATION. WILL GET SECONDARY AREA WITH MAIN DIV Q/PV ADVECTION LATER IN NIGHT FROM SOUTHWEST...WHICH SHOULD MAKE FOR MORE WIDESPREAD SHOWERS...BECOMING MORE STRATIFORM BACK IN DEFORMATION THROUGH WESTERN CWA. WOULD NOT BE SURPRISED TO FIND A FEW RUMBLES OF THUNDER BY LATE NIGHT GIVEN THE 800 HPA LI NEAR ZERO. THIS COULD PRESENT A SMALL WILD CARD TOWARD TYPE IF DEEPER CONVECTION BECOMES ESTABLISHED. HOWEVER...FOR THE MOST PART...HARD TO PICTURE A GREAT DEAL OF SNOW WITH MOST OF THE PRECIPITATION ON SATURDAY NIGHT...WITH MORE INTENSITY IN THE FAR WEST AND SOME SLIGHTLY COOLER/DRIER AIR TO THE NORTH AIDING IN MIX/CHANGE POTENTIAL. INVERTED TROUGH SHOULD BE FAIRLY CLOSE TO THE JAMES VALLEY BY DAYBREAK SUNDAY...PERHAPS A BIT WESTWARD...WITH BULK OF ANY FROZEN PRECIPITATION FORCED ALONG AND BEHIND FEATURE. MODEL TRENDS ARE STARTING TO GRAVITATE TOWARD A SOLUTION CENTERED AROUND AN ECMWF/GFS TRACK TO WAVE AS IT PUSHES OUT INTO THE PLAINS AND ACROSS THE AREA ON SUNDAY. NAM CONTINUES TO BE THE NORTHERN AND CANADIAN GLOBAL THE SOUTHERN OUTLIERS. FOLLOWING ALONG THE GENERAL GUIDANCE...WAVE WILL PUSH VERY CLOSE TO THE MIDDLE OF THE CWA... PERHAPS A BIT TO THE EAST...COLLAPSING THE INVERTED TROUGH CLOSER TO I29 BY MIDDAY. FAIRLY SOLID LOOK TO DRY SLOT PUSHING NORTHWARD THROUGH EASTERN CWA AHEAD OF THIS FEATURE...AND TRENDED BACK POPS TOWARD SCATTERED FOR A TIME DURING THE MORNING...WITH PERHAPS A LITTLE THUNDER AS WELL. WIDESPREAD PRECIPITATION BACK TO THE WEST AS TROWAL BECOMES FAIRLY WELL ESTABLISHED BY EARLY SUNDAY... WITH LIFT INITIALLY INDICATED ON THE NORTHWEST FLANK. HOWEVER... FRONTOGENETIC FORCING GRADUALLY INCREASES ON THE SOUTHEAST FLANK OF THE TROWAL AS SUNDAY GOES ON...WITH LOW EPV SUPPORTING AN ENHANCING FRONTAL CIRCULATION...THE FOCUS FOR THE SOUTHEASTWARD COLLAPSING SNOW BAND ON LATER SUNDAY AFTERNOON AND EVENING. FAIRLY STRONG LIFT IN THE DENDRITIC GROWTH ZONE INDICATED...BUT NOT TOO DEEP A LAYER... AND EFFICIENCY MAY SUFFER A BIT FOR THAT. SNOW RATIO IN MAX BAND FROM 12-16 TO 1. RESULTING 8-12 INCHES OF SNOWFALL EXPECTED OVER THE NORTHWEST THIRD OR SO OF THE AREA WILL INTERACT WITH STRONG NORTH TO NORTHWEST WINDS BEHIND THE INVERTED TROUGH AS SYSTEM WRAPS UP LATER SUNDAY AND SUNDAY NIGHT. WITH 30-40 KNOTS OF 925 HPA WIND...SHOULD EASILY SUPPORT THREAT OF BLIZZARD CONDITIONS. SHARPENED UP WITH OVERALL SNOWFALL TOTALS ON THE SOUTHEAST SIDE OF THE BAND...AND WILL LIKELY NEED FURTHER SHARPENING ONCE DETERMINATION OF THE LONGER LINGERING TROWAL SNOWFALL CAN BE DETERMINED. IN TERMS OF HEADLINE DECISIONS...FAIRLY OBVIOUS NEED TO DELAY THE START TIME IN THE WESTERN GROUP BY AT LEAST 6H...WITH VERY LITTLE SNOWFALL AND THE WIND LIKELY NOT MUCH OF AN ISSUE UNTIL WELL AFTER 06Z. CONSIDERED DELAYING START TO THE MORE EASTERN GROUP AS WELL FOR SIMILAR REASONS...ESPECIALLY THE FAR EAST WHICH WILL NOT SEE INVERTED TROUGH PASSAGE AND INCREASE IN WINDS UNTIL TOWARD EVENING ON SUNDAY. DID SPLIT OFF THE FAR EASTERN AREAS AND DELAY START UNTIL LATE AFTERNOON SUNDAY...AND ADDED IN A FEW COUNTIES BORDERING THE EAST EDGE OF THE EXISTING WATCH...MAINLY WHERE SNOWFALL OF 3 TO 4 INCHES WOULD BE COMBINING WITH GUSTY NORTHWEST WINDS TO 25 TO 40 MPH. ALSO...GIVEN THE WINDS WHICH ARE LIKELY TO ONLY BE ON A SLOW DOWNWARD TREND BY EARLY MONDAY...EXTENDED THE WATCH THROUGH MIDDAY MONDAY...BUT WORST CONDITIONS ARE CERTAINLY TO BE EXPECTED FROM EAST CENTRAL SD INTO NORTHERN PARTS OF SW MN BY MONDAY MORNING. CHANGES TO THE TUE THROUGH FRIDAY TIME PERIOD LIMITED DUE TO ATTENTION ON THE MUCH MORE SIGNIFICANT ISSUES OF THE SHORTER TERM. CLIPPER SYSTEM WORKING SOUTHEAST WEDNESDAY NIGHT AND THURSDAY SHOULD BE ACCOMPANIED BY A PERIOD OF SNOW SHOWERS...WITH AMPLIFICATION OF SYSTEM DRAWING DOWN SOME MUCH COLDER AIR. MAY BE A LITTLE MORE MESSY THAN CURRENTLY GIVING CREDIT FOR...WITH AMPLIFICATION STRENGTHENING GRADIENT TO 35 TO 45 KNOTS AT 925 HPA BEHIND SYSTEM ON THURSDAY AND THURSDAY EVENING. FOR THE TIME...INCREASED POPS A TOUCH OVER THE INITIALIZATION SLIGHTS/LOW CHANCE. /CHAPMAN && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...BLIZZARD WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR MNZ071-072-097. BLIZZARD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR MNZ080-081-098. NE...NONE. SD...BLIZZARD WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR SDZ040-054>056-059>062-064-065-068. BLIZZARD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR SDZ066-067-069. BLIZZARD WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY MORNING FOR SDZ038-039-050-052-053-057-058-063. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
902 PM CST SUN FEB 10 2013 .UPDATE...LATEST RUC AND NAM PROJECTIONS SHOW OVERNIGHT CLEARING TO BE A BIT SLOWER THAN PREVIOUSLY EXPECTED. THEREFORE, HAVE UPDATED OVERNIGHT AND MONDAY MORNING CLOUD FORECAST TO REFLECT THIS. EVEN THOUGH THE BULK OF THE PRECIPITATION HAS MOVED EAST OF THE MID STATE, WE WILL STILL HAVE AT LEAST A SMALL CHANCE FOR SHOWERS AND, PERHAPS, EVEN AN ISOLATED THUNDERSTORM UNTIL SURFACE FRONT PASSES LATER TONIGHT. HAVE MADE ONLY MINOR CHANGES TO OVERNIGHT GRIDS TO REFLECT CURRENT TRENDS, BUT WILL GO AHEAD AND RELEASE A ZFP UPDATE TO KEEP EVERYTHING IN SYNC. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 19
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
842 PM CST SUN FEB 10 2013 .UPDATE... ONLY SOME MINOR CHANGES NEEDED TO THE CURRENT FORECAST. WATER VAPOR IMAGERY SHOWS THE POWERFUL UPPER STORM THAT BROUGHT LAST NIGHTS WEATHER NOW MOVING INTO THE UPPER MIDWEST. THERE IS ANOTHER UPPER TROUGH OVER THE WESTERN US AND THIS IS HELPING KEEP NORTH TEXAS IN A FAST SOUTHWEST FLOW ALOFT. FORT WORTH RAOB SAMPLED A 150KT UPPER JET AT 230MB. THERE IS SOME MOISTURE ALSO STREAMING OVERHEAD AS INDICATED BY THE PARTIAL CLOUD COVER. FARTHER SOUTH...MOISTURE IS A LITTLE BETTER AND RAP FORECAST SOUNDINGS ACTUALLY INDICATE SOME SATURATION ABOVE 600MB. THIS IS RESULTING IN SOME LIGHT PRECIPITATION ACROSS THE FAR SOUTHERN COUNTIES...HOWEVER GIVEN THE DRY AIR BENEATH IT...MOST OF THE RETURNS ON THE RADAR ARE VIRGA. NOT EXPECTING ANY PRECIP TO REACH THE GROUND OVERNIGHT TONIGHT. BETTER RAIN CHANCES WILL ARRIVE LATE TOMORROW AND PERSIST INTO TUESDAY. CHANGES TO CURRENT FORECAST WERE LIMITED TO HOURLY TEMPERATURES AND SKY COVER. DUNN && .AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH 06Z TUESDAY. LIGHT WEST TO NORTHWEST WINDS THIS EVENING WILL BECOME NORTHEAST AT 5 TO 10 KNOTS BEFORE DAYBREAK AND EASTERLY MONDAY AFTERNOON. THERE WILL BE SOME LOW RAIN CHANCES LATE MONDAY AFTERNOON THROUGH THE EVENING IN THE METROPLEX...BUT THE CHANCES ARE NOT HIGH ENOUGH TO MENTION IN THE TAFS. RAIN CHANCES MONDAY AFTERNOON IN THE WACO AREA MAY PROMPT THE ADDITION OF VCSH WITH THE 03Z UPDATES. RAIN CHANCES WILL IMPROVE AREA WIDE AFTER MIDNIGHT. 58 && .PREV DISCUSSION... /ISSUED 348 PM CST SUN FEB 10 2013/ AFTERNOON WATER VAPOR SATELLITE IMAGERY INDICATED A POWERFUL UPPER LOW OVER THE NORTH PLAINS WITH A STRONG SHORTWAVE TROUGH LOCATED OVER EASTERN NEVADA. AFTERNOON SURFACE OBSERVATIONS SHOWED WESTERLY WINDS OVER ALL OF NORTH AND CENTRAL TX...THE RESULT OF A PACIFIC TYPE COLD FRONT THAT MOVED THROUGH OVERNIGHT AND WAS ACCOMPANIED BY A LINE OF STRONG TO SEVERE THUNDERSTORMS. PERSISTENT WESTERLY FLOW HAS ADVECTED A VERY DRY AIR MASS OVER NORTH TX THIS AFTERNOON WITH DEW POINTS OBSERVED IN THE TEENS WEST OF THE INTERSTATE 35 CORRIDOR AND IN THE UPPER 20S TO LOWER 30S TO THE EAST. PERSISTENT CLOUD COVER HAS HELD TEMPERATURES IN THE MID 60S FOR MOST LOCATIONS...DESPITE THE DRY AIR IN PLACE. TONIGHT THROUGH WEDNESDAY...THE NEVADA SHORTWAVE TROUGH WILL CONTINUE TO SINK SOUTH-SOUTHEAST THROUGH TOMORROW MORNING AS IT MERGES WITH A SECOND...COMPACT AND VERY FAST MOVING...TROUGH COMING OUT OF WESTERN CANADA. AS THIS TROUGH APPROACHES THE REGION IT WILL SPREAD LARGE SCALE FORCING FOR ASCENT OVER THE CWA...RESULTING IN AN INCREASE IN LOW LEVEL CLOUD COVER FROM SOUTHEAST TO NORTHWEST THROUGH MONDAY AFTERNOON. THIS MOISTURE RETURN WILL LIKELY RESULT IN ISOLATED RAIN SHOWERS DEVELOPING ALONG AND SOUTHEAST OF AN ATHENS TO GATESVILLE LINE MONDAY MORNING...SPREADING NORTHWEST TOWARDS THE DFW METROPLEX BY MONDAY AFTERNOON. DUE TO THE VERY DRY AIR CURRENTLY IN PLACE...THINK THAT RAINFALL WILL BE LIGHT IN NATURE...WITH INITIAL RAIN SHOWERS WORKING TO SATURATE THE NEAR SURFACE LAYER FROM THE TOP DOWN RESULTING IN VIRGA AND LOWERING CLOUD DECKS. HIGHS ON MONDAY WILL LIKELY STRUGGLE TO REACH 60 DEGREES FOR THE SOUTHEASTERN PORTIONS OF THE CWA WITH MOSTLY CLOUDY SKIES AND ISOLATED RAIN SHOWERS TO CONTEND WITH. ELSEWHERE HIGHS WILL LIKELY ONLY REACH THE LOWER 60S. ISOLATED RAIN SHOWERS WILL SPREAD NORTH OVER THE ENTIRE CWA MONDAY EVENING AS THE TROUGH BEGINS TO MOVE EAST-NORTHEAST TOWARDS THE SOUTH PLAINS. MOST GUIDANCE BRINGS NUMEROUS RAIN SHOWERS OVER NORTH AND CENTRAL TX LATE MONDAY NIGHT AND INTO TUESDAY MORNING AS THE BEST LARGE SCALE FORCING FOR ASCENT MOVES OVER NORTH TX. DID NOT MAKE ANY REAL CHANGE TO THE PREVIOUS FORECAST DURING THIS PERIOD AS LIKELY /60 TO 70/ POPS SEEM APPROPRIATE FOR THE EXPECTED COVERAGE OF RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING. MAINTAINED THE MENTION OF ISOLATED THUNDERSTORMS EMBEDDED IN THE MORE WIDESPREAD RAIN SHOWER ACTIVITY BECAUSE BOTH THE GFS AND ECMWF INDICATE THAT WE WILL RECEIVE A GOOD INFLUX OF MID TO UPPER LEVEL MOISTURE AS A WEAK SHORTWAVE TROUGH OVER THE OPEN WATERS OF THE PACIFIC IS DRAWN OVER THE REGION DURING THIS TIME. MOST OF THE RICH/TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE WILL BE SCOURED OUT BY THE HIGH TERRAIN OF MEXICO...BUT WHAT REMAINS WILL CERTAINLY HELP SUPPORT WIDESPREAD RAIN SHOWERS MONDAY NIGHT AND TUESDAY MORNING. AS OPPOSED TO OUR LAST SYSTEM...MODELS DO NOT FORECAST STEEP MID-LEVEL LAPSE RATES BEFORE PRECIPITATION BEGINS...SO THINK THAT ANY EMBEDDED THUNDERSTORMS ARE VERY UNLIKELY TO PRODUCE SEVERE WEATHER AT THIS TIME. AS THE WEAK PACIFIC OCEAN ENERGY MOVES EAST OF THE REGION...IT WILL BE REPLACED BY A GOOD MID TO UPPER LEVEL DRY SLOT WORKING IN BEHIND OUR NEVADA SHORTWAVE WHICH IS EXPECTED TO MOVE EAST...RIGHT ALONG THE RED RIVER DURING THE DAY ON TUESDAY. THIS DRY SLOT WILL BRING AND END TO PRECIPITATION OVER THE CWA FROM SOUTHWEST TO NORTHEAST TUESDAY AFTERNOON AS THE DRY SLOT WORKS TO DRY OUT THE ATMOSPHERE FROM THE TOP DOWN. DEPENDING ON THE EXACT TRACK OF THE NEVADA SHORTWAVE TROUGH...WE MAY SEE SOME PRECIPITATION LINGER JUST SOUTH OF THE RED RIVER TUESDAY EVENING AS COLDER AIR BUILDS INTO THE REGION FROM THE NORTHWEST. THE CONSENSUS OF 10/12Z GUIDANCE CONTINUES TO INDICATE THAT THE TROUGH WILL MOVE EAST RIGHT ALONG THE RED RIVER WHICH KEEPS ANY CHANCE OF A CHANGE OVER TO SNOW NORTH OF THE RED RIVER AT THIS TIME. EVEN THE ECMWF...WHICH HAS BEEN MOST AGGRESSIVE WITH COLD AIR ADVECTION ON THE BACK SIDE OF THIS TROUGH...KEEPS TEMPERATURES NEAR THE RED RIVER IN THE UPPER 30S WHILE THERE IS STILL ENOUGH MOISTURE IN PLACE FOR PRECIPITATION TO DEVELOP NEAR THE CWA. AS A RESULT...KEPT A SLIGHT CHANCE FOR RAIN/RAIN SHOWERS IN THE FORECAST NEAR THE RED RIVER THROUGH MIDNIGHT/06Z TUESDAY NIGHT. EXTENDED...COLDER AIR WILL BUILD INTO NORTH AND CENTRAL TX BEHIND THE NEVADA SHORTWAVE TROUGH. HOWEVER PERSISTENT NORTHWEST/WESTERLY FLOW WILL ONCE AGAIN SCOUR LOW LEVEL MOISTURE WELL AWAY FROM THE REGION REDUCING THE CHANCE OF ANY PRECIPITATION THROUGH THE REMINDER OF THE WEEK. WE ARE EXPECTED TO REMAIN IN A SOMEWHAT ACTIVE/FAST FLOW REGIME ALOFT WHICH WILL SEND A COUPLE OF WEAK UPPER LEVEL DISTURBANCES OVER THE CWA FOR THE LATTER HALF OF THE UPCOMING WORK WEEK. NONE OF THESE DISTURBANCES IS PARTICULARLY IMPRESSIVE IN NATURE IN TERMS OF ABILITY TO SPREAD LARGE SCALE FORCING FOR ASCENT OVER THE REGION. WE WILL LIKELY SEE SKIES CLOUD UP AS EACH DISTURBANCE PASSES BY...BUT WITHOUT BETTER MOISTURE TO WORK WITH...THINK THAT CHANCE OF ANY PRECIPITATION WILL REMAIN LOW THROUGH THE END OF THE WEEK. THE ECMWF HAD BEEN DRAGGING A STRONG BUT POSITIVELY TILTED TROUGH OVER THE SOUTH PLAINS AT THE END OF THE WEEK. THIS WOULD HAVE SPREAD MORE PERSISTENT LARGE SCALE FORCING FOR ASCENT OVER THE CWA WHICH MAY HAVE RESULTED IN SOME LIGHT PRECIPITATION...AND POSSIBLY EVEN SOME WINTRY WEATHER. HOWEVER TODAYS 12Z ECMWF IS IN MUCH BETTER AGREEMENT WITH THE GFS WHICH KEEPS A LARGE TROUGH OVER THE NORTHEASTERN CONUS...WITH ONLY TRANSIENT/WEAK DISTURBANCES PROVIDING LIFT OVER THE CWA THROUGH NEXT WEEKEND. AS A RESULT MAINTAINED A DRY FORECAST THROUGH NEXT WEEKEND...WITH TEMPERATURES HOLDING NEAR OR MAYBE SLIGHTLY BELOW SEASONAL NORMALS AS EACH UPPER DISTURBANCE SENDS A REINFORCING SHOT OF COOL AIR INTO NORTH AND CENTRAL TX. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 44 60 45 54 38 / 0 10 50 70 10 WACO, TX 42 62 48 63 40 / 5 20 50 50 10 PARIS, TX 38 60 42 46 38 / 0 10 30 70 20 DENTON, TX 37 61 44 49 36 / 0 10 50 70 20 MCKINNEY, TX 38 61 44 49 37 / 0 10 50 70 20 DALLAS, TX 46 60 46 55 39 / 0 10 50 70 10 TERRELL, TX 42 60 45 55 39 / 0 20 40 70 10 CORSICANA, TX 47 58 47 59 41 / 5 20 40 60 10 TEMPLE, TX 46 63 49 65 40 / 5 30 50 50 10 MINERAL WELLS, TX 38 62 44 56 35 / 0 10 60 50 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
547 PM CST SUN FEB 10 2013 .DISCUSSION... SEE AVIATION SECTION. && .AVIATION... VFR CONDITIONS WILL PREVAIL AT THE TAF SITES TONIGHT AND MONDAY. SOME INCREASE IN HIGH CLOUD COVERAGE IS EXPECTED TONIGHT. SOME MID-LEVEL CLOUD DEVELOPMENT IS EXPECTED ACROSS SOUTHERN SECTIONS OF WEST CENTRAL TEXAS LATE TONIGHT AND MONDAY. A FEW SPRINKLES OR PERHAPS A LIGHT RAIN SHOWER IS POSSIBLE MONDAY...TO THE EAST OF THE KJCT AND KBBD TERMINALS. WINDS WILL BE LIGHT AND VARIABLE TONIGHT. EAST-SOUTHEAST WINDS WILL DEVELOP ON MONDAY AND INCREASE TO 8-12 KT. 19 && .PREV DISCUSSION... /ISSUED 349 PM CST SUN FEB 10 2013/ SHORT TERM... RELATIVELY QUIET WEATHER CONDITIONS IN THE SHORT TERM PERIOD. A WEAK FRONT WILL ENTER THE BIG COUNTRY LATE TONIGHT BUT WILL WASH OUT ACROSS THE AREA ON MONDAY. SUBTROPICAL JET WILL CONTINUE TO FEED MID AND HIGH LEVEL MOISTURE FROM THE SOUTHWEST ACROSS MAINLY SOUTHERN SECTIONS OVERNIGHT. THE NAM CONTINUES TO SHOW SOME LIGHT RAIN SHOWERS DEVELOPING OVER EXTREME SOUTHEAST COUNTIES ON MONDAY IN AN AREA OF WEAK ISENTROPIC ASCENT/WAA. 3KM WRF AND LATEST RUC ALSO HINTING AT THIS POSSIBILITY SO WILL KEEP SLIGHT CHANCE POPS INTACT THIS FORECAST CYCLE. CLOUD COVER WILL LIMIT COOLING ACROSS SOUTHEAST SECTIONS TONIGHT WITH LOWS MAINLY IN THE LOWER 40S. LIMITED CLOUD COVER...LIGHT WINDS AND A DRY AIRMASS WILL ALLOW TEMPS TO COOL INTO THE LOW TO MID 30S ACROSS THE REMAINDER OF THE AREA. MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE ON MONDAY WITH AFTERNOON HIGHS RANGING FROM THE LOW TO MID 60S NORTH TO THE MID AND UPPER 60S SOUTH. 24 LONG TERM... UPPER LOW NEAR THE FOUR CORNERS LATE MONDAY WILL WILL DIG SOUTHEAST TUESDAY INTO NEW MEXICO. SURFACE TO 850MB LAYER WILL QUICKLY SATURATE OVER THE ENTIRE CWA BY MIDNIGHT MONDAY CONCOMITANT WITH AN INTENSIFYING LLJ...40-50KT CENTERED OVER THE SOUTHWESTERN CWA. THE HEAVIEST RAINFALL ACCUMULATION CHANCES WILL BE OVER THE BIG COUNTRY ON THE NOSE OF THE LOW LEVEL JET BEGINNING AROUND MIDNIGHT MONDAY AND LASTING INTO TUESDAY MORNING. HAVE INCLUDED THE MENTION OF CONVECTIVE ACTIVITY MONDAY NIGHT THROUGH TUESDAY AS THE COLD FRONT/DRYLINE MOVES EAST THROUGH THE FORECAST AREA. LATEST SPC CONVECTIVE OUTLOOK MENTIONS VIA A SEE TEXT THE POSSIBILITY FOR LARGE HAIL FOR OUR AREA BASED ON SUFFICIENT INSTABILITY AND SHEAR VALUES FOR ELEVATED SUPERCELLS...AS REFLECTED IN THE LATEST FORECAST SOUNDINGS...WILL CONTINUE TO EVALUATE THIS POSSIBILITY. PRECIPITATION CHANCES WILL BE CONFINED TO OUR EASTERN TIER OF COUNTIES BY TUESDAY AFTERNOON WITH PRECIPITATION ENDING OVER ALL OF THE FORECAST AREA BY TUESDAY EVENING. TUESDAY MORNING LOWS WILL RANGE FROM THE LOWER 40S TO AROUND 50 DEGREES AND TUESDAY AFTERNOON HIGHS WILL RANGE FROM THE MID 50S TO THE MID 60S UNDER CLOUDY SKIES. AFTERNOON HIGHS AND MORNING LOWS WILL REMAIN NEAR CLIMO THROUGH THE COMING WEEKEND...GENERALLY IN THE LOWER 60S FOR HIGHS AND THE MID 30S FOR LOWS. THE NEXT COLD FRONTAL PASSAGE WILL BE LATE THURSDAY WITH LITTLE IMPACT ON THE FORECAST AREA. 15 && .PRELIMINARY POINT TEMPS/POPS... ABILENE 33 64 46 58 32 / 0 5 60 40 10 SAN ANGELO 34 70 50 64 35 / 0 10 50 10 5 JUNCTION 43 68 45 66 35 / 0 20 50 20 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
357 PM CST SAT FEB 9 2013 .DISCUSSION... GUSTY SOUTHEAST SURFACE WINDS THIS AFTERNOON AS STRONG MOISTURE ADVECTION CONTINUES AHEAD OF AN APPROACHING UPPER LEVEL SYSTEM. A FEW SHOWERS AND THUNDERSTORMS DEVELOPED ALONG THE WARM FRONT EARLIER THIS AFTERNOON AS IT LIFTED NORTH OF THE REGION. THE WARM FRONT IS CURRENTLY ALONG A LINE FROM JUST SOUTH OF WICHITA FALLS TO DALLAS TO NACOGDOCHES...WITH A DRYLINE SETTING UP ACROSS WEST TEXAS. THIS DRYLINE WILL SERVE AS THE INITIAL FOCUS FOR THUNDERSTORM DEVELOPMENT LATER THIS EVENING AS A PACIFIC FRONT OVERTAKES IT FROM THE WEST. ONLY VERY LIGHT SHOWERS ONGOING ACROSS SOUTHEAST TEXAS THIS AFTERNOON AND THIS WILL CONTINUE THROUGH MUCH OF THE EVENING AS A CAPPING INVERSION REMAINS IN PLACE ACROSS OUR REGION. ACARS SOUNDINGS FOR IAH AND HOU SHOW TWO DISTINCT TEMPERATURE INVERSIONS NEAR 850 AND 700MB ALTHOUGH LATEST DATA SUGGEST SOME WEAKENING OF THESE FEATURES AS WE APPROACH LATE AFTERNOON. THE GFS IS HINTING AT A WEAK SHORTWAVE MOVING ACROSS OUR NORTHERN COUNTIES AROUND MIDNIGHT TONIGHT AND LATEST HRRR RUNS SHOW AN AREA OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS CENTRAL TEXAS OVERNIGHT AHEAD OF THE APPROACHING FRONTAL BOUNDARY. THIS ACTIVITY WILL INCREASE IN COVERAGE TOWARDS DAYBREAK AS THE FRONTAL BOUNDARY APPROACHES OUR REGION. THE GREATEST COVERAGE AND GREATEST POTENTIAL FOR ANY STRONG TO SEVERE THUNDERSTORMS ACROSS OUR REGION IS STILL EXPECTED TO BE ACROSS AREAS TO THE NORTH AND EAST OF A LINE FROM BRYAN TO GALVESTON. AREAS FURTHER TO THE SOUTH AND WEST WILL BE MORE CAPPED AND COVERAGE WILL BE LIMITED. THE GREATEST THREAT FROM THESE THUNDERSTORMS WILL BE STRONG DAMAGING WINDS...AS THE LOW LEVEL FLOW WILL REMAIN QUITE STRONG ACROSS OUR REGION. RAIN CHANCES WILL END BY SUNDAY AFTERNOON AS THE FRONT SWEEPS THROUGH SOUTHEAST TEXAS. WHILE THE FRONT MOVES THROUGH OUR REGION THE ASSOCIATED UPPER LEVEL LOW WILL MOVE RAPIDLY TO THE NORTHEAST. IN ITS WAKE ANOTHER SHORTWAVE WILL MOVE INTO THE BASE OF THE UPPER TROUGH AND DIG INTO THE DESERT SOUTHWEST. RAIN CHANCES WILL RETURN TO OUR AREA BY MONDAY EVENING AS ISENTROPIC LIFT BEGINS AHEAD OF THIS APPROACHING UPPER LOW. THIS SYSTEM WILL MOVE THROUGH NORTH TEXAS TUESDAY NIGHT ALLOWING COLDER AIR TO MOVE INTO THE STATE FOR WEDNESDAY. DRIER AND COOLER WEATHER WILL PERSIST THROUGH THE LATTER HALF OF THE WEEK WITH HIGHS IN THE 60S AND LOWS IN THE 40S. MODEL SOLUTIONS BEGIN TO DIVERGE LATE AS THE GFS BECOMES PROGRESSIVE AND ALLOWS THE UPPER TROUGH TO EXIT TO THE EAST WHILE THE LATEST ECMWF RUN HOLDS SOME ENERGY OFF TO THE WEST AND INITIATES ANOTHER ROUND OF ISENTROPIC UPGLIDE FOR THE WEEKEND. FOR NOW WILL KEEP THE FORECAST RELATIVELY DRY FOR SATURDAY AND WAIT FOR BETTER MODEL AGREEMENT BEFORE ADJUSTING TO A COOLER AND WETTER FORECAST FOR NEXT WEEKEND. 38 && .MARINE... TIDES AROUND 1 TO 2 FEET ABOVE NORMAL TONIGHT SLOWLY IMPROVING SUNDAY AND MONDAY THOUGH NORTHEASTERLY FLOW WILL KEEP TIDES UP. WINDS OVER THE COASTAL WATERS WILL BE INCREASING TONIGHT AND HAVE CONTINUED THE SCEC. SEAS SHOULD BUILD TO 4 TO 7 FEET AND CONTINUE THROUGH SUNDAY AFTERNOON THEN WITH WINDS DROPPING OFF EXPECT SEAS TO SLOWER. NORTHEASTERLY FLOW INCREASE LATE SUNDAY NIGHT AND MONDAY WILL SEAS BUILD BACK IN BUT ONLY TO 3 TO 5 FEET. EASTERLY FLOW AS FRONT STALLS THEN SLOWLY LIFTS BACK NORTH AND MAY HAVE A WINDOW OF 12-30 HOURS FOR FOG BEFORE THE NEXT FRONT COMES COMES IN AFTER 6 PM TUESDAY. 45 && .AVIATION... CIGS LOWERING OVER THE AREA AS EXPECTED BUT PERHAPS A LITTLE FASTER THAN EXPECTED. ALSO SEEING SOME FOG NEAR GALVESTON AT 3SM. EXPECTING SHOWERS TO DEVELOP THROUGHOUT THE NIGHT AFTER 05Z AND SPREAD EAST THROUGH THE AREA. ISOLATED-SCATTERED THUNDERSTORMS POSSIBLE (SEE ABOVE) WILL CONTINUE THE VCSH/VCTS AND TEMPOS FOR THE SAME WINDOW. IAH SOUTHWARD MAY HAVE A STINT OF IFR-LOW MVFR CIGS/FOG MONDAY MORNING THROUGH TUESDAY WITH THE STATIONARY FRONT. 45 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 63 74 49 65 50 / 60 70 20 30 30 HOUSTON (IAH) 64 76 57 69 53 / 40 60 20 30 30 GALVESTON (GLS) 64 71 60 68 58 / 20 50 30 30 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST SUNDAY FOR THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM. SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH LATE TONIGHT FOR THE FOLLOWING ZONES: GALVESTON BAY. SMALL CRAFT ADVISORY UNTIL NOON CST SUNDAY FOR THE FOLLOWING ZONES: WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL NOON CST SUNDAY FOR THE FOLLOWING ZONES: WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...38 AVIATION/MARINE...45
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
304 PM CST SAT FEB 9 2013 .SHORT TERM... A BUSY AFTERNOON IS IN STORE FOR THE CWA... WITH BOTH HIGH WINDS IN THE WEST AND THE POSSIBILITY FOR STORMS IN THE EAST. AS EXPECTED... A POTENT TROUGH IS CURRENTLY ADVANCING ON WEST TEXAS... WITH A 500MB KT MAX OF OVER 100KT CURRENTLY SITUATED OVER EASTERN NEW MEXICO. HIGH CLOUDS HAVE CLEARED OVER MOST OF THE NW PORTION OF THE CWA AND NEW MEXICO...ALLOWING FOR DEEP MIXING AND VERY STRONG WINDS ACROSS MOST OF EASTERN NEW MEXICO. WINDS HAVE BEEN SLOW TO VEER IN WEST TEXAS THIS AFTERNOON...ALLOWING DEWPOINTS TO CLIMB INTO THE UPPER 30S AND NEAR 40 ACROSS MOST OF THE CAPROCK AS OF 18Z. HOWEVER... SURFACE OBS AND RADAR TRENDS ARE INDICATING THAT WINDS ARE FINALLY BEGINNING TO VEER SLIGHTLY IN THE WEST... WHICH HAS RESULTED IN RAPID DRYING AND INCREASING WIND SPEEDS JUST EAST OF THE TEXAS NEW MEXICO BORDER. GIVEN THESE TRENDS... HAVE OPTED TO UPGRADE PARMER...CASTRO AND BAILEY COUNTIES TO A HIGH WIND WARNING THROUGH 02Z. FIRE WEATHER CONCERNS ARE STILL MINIMAL... ESPECIALLY GIVEN THE HIGHER THAN ANTICIPATED DEWPOINTS ACROSS THE WEST AND MOIST FUEL CONDITIONS... HOWEVER ELEVATED FIRE WEATHER CONDITIONS AND SOME RED FLAG MINUTES WILL BE PRESENT NEAR THE TX/NM BORDER THROUGH THE EARLY EVENING WHERE THE AIR WILL BE DRIEST AND WINDS STRONGEST. FURTHER EAST... THE FORECAST STILL APPEARS TO BE LARGELY ON TRACK AS MOISTURE CONTINUES TO RETURN ACROSS THE EAST. RADAR AND SURFACES OBSERVATIONS INDICATE THE BEGINNINGS OF A DRYLINE FORMING JUST TO THE EAST OF THE TX/NM STATE LINE...AND APPEARS TO BE SLOWLY ADVANCING EAST. IN ADDITION... VISIBLE SATELLITE IMAGERY IS SHOWING AN INCREASE IN CUMULIFORM CLOUDS JUST TO THE DRY SIDE OF THIS DEVELOPING DRYLINE. DEWPOINTS AS OF 20Z HAVE REACHED THE UPPER 40S ACROSS THE SOUTHEAST...TO NEAR 40 IN THE NORTHERN ROLLING PLAINS...WHICH IS A BIT LOWER THAN YOU WOULD LIKE FOR STORM DEVELOPMENT. AS SUCH... INSTABILITY IS STILL VERY WEAK ACROSS THE AREA...WITH MAXIMUM VALUES OF NEAR 500 J/KG RESTRICTED TO THE SOUTHEAST. THERE STILL REMAINS SOME TIME FOR MOISTURE TO INCREASE...AND IT STILL SEEMS WITHIN REASON THAT DEWPOINTS WILL REACH THE UPPER 40S TO LOW 50S WITHIN THE NEXT FEW HOURS. LOCAL HIGH RESOLUTION MODELS...INCLUDING THE TTUWRF AND TO A LESSER EXTENT THE HRRR... SEEM TO BE SUGGESTING THAT INITIATION MAY HOLD OFF UNTIL 00Z... HOWEVER THE RUC IS STILL FIRING AROUND 22Z. GIVEN CURRENT TRENDS... IT SEEMS THAT THE LATER INITIATION SOLUTIONS SEEM MORE PLAUSIBLE. GIVEN THE VERY STRONGLY SHEARED WIND FIELDS... ANY STORMS THAT CAN MANAGE TO INITIATE EARLY WILL VERY LIKELY BE SUPERCELLULAR... AND COULD POSE A VERY ISOLATED TORNADO THREAT IF MOISTURE CAN CONTINUE TO RISE. HOWEVER...THIS THREAT APPEARS TO BE VERY MARGINAL AT THIS TIME... AND A MORE LIKELY THREAT WILL BE MARGINALLY SEVERE HAIL TO 1" AND DAMAGING WINDS TO 70 MPH. THE MOST LIKELY AREA FOR INITIATION STILL APPEARS TO BE NORTH OF LBB AND EASTWARD TOWARDS THE CHILDRESS AREA. LATER IN THE EVENING...A PACIFIC FRONT WILL SWEEP THROUGH THE AREA...AND LIKELY INITIATE MORE STORMS WITH A MORE LINEAR MODE. STORMS WILL LIKELY EXIT THE AREA TO THE EAST BY 06Z. FOR TOMORROW...BREEZY WESTERLY WINDS BETWEEN 20-30 MPH WILL PERSIST ACROSS THE AREA DURING THE AFTERNOON...WHICH WHEN COMBINED WITH LOW DEWPOINTS WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS....ESPECIALLY ACROSS THE ROLLING PLAINS WHERE WARMER TEMPERATURES WILL RESULT IN LOWER RH VALUES... && .LONG TERM... BY SUNDAY EVENING...FLOW ACROSS THE REGION WILL BE ZONAL TO SLIGHTLY WEST SOUTHWESTERLY AS TODAY/S WIND MAKER EJECTS INTO THE GREAT LAKES. TROUGH OUT WEST CONTINUES TO DEEPEN AND APPROACH LATE MONDAY NIGHT. FLOW BECOMES NORTHWESTERLY BY WEDNESDAY WITH AN EMBEDDED TROUGH DUE IN ON THURSDAY AND ANOTHER TROUGH DIGGING INTO THE SOUTHWEST BY FRIDAY THOUGH MORE LATITUDINALLY ORIENTED THAN THE EARLY WEEK SYSTEM. RIDGING BUILDS OUT WEST WITH STRONG NNW FLOW WITH DECENT COLD AIR ADVECTION. COLD FRONT SHOULD FINALLY MAKE IT INTO THE AREA SUNDAY EVENING WITH WINDS BECOMING MORE OR LESS EASTERLY AND REMAINING IN FAVORABLE UPSLOPE REGIME FOR MOISTURE ADVECTION. NAM/GFS/ECM HAVE COME INTO GOOD AGREEMENT WITH SOME FAIRLY SUBSTANTIVE MOISTURE ADVECTION MONDAY EVENING PERHAPS MAKING IT A BIT FURTHER WEST THAN EARLIER THOUGHT. NEVERTHELESS...GENERAL TRENDS IN THE FORECAST REMAIN INSOFAR AS MOISTURE GOES...BUT...WITH THE GREATER MOISTURE...PRECIPITATION PHASE IS A BIT LESS CERTAIN WITH PHASE REMAINING LIQUID UNTIL WRAP AROUND ON THE BACK SIDE OF THE LOW...WITH LOWER TEMPS. GIVEN THIS FAIRLY RADICAL CHANGE THIS RUN...WILL HOLD OFF ON MAKING MAJOR CHANGES TO ONGOING FORECAST FOR NOW. INTO WEDNESDAY...DRIER AIR WILL CONTINUE TO FILTER INTO THE REGION AND START A WARMING TREND AFTER BOTTOMING OUT ON TUESDAY. THOUGH WINDS BACK TO SOUTHWESTERLY ON WEDNESDAY...COLD FRONT IN WEDNESDAY NIGHT/THURSDAY MORNING WILL USHER IN BREEZY NORTHERLY WINDS ONCE AGAIN WITH YET COOLER AIR SURGING SOUTHWARD INTO FRIDAY WITH DRY WEATHER TO PREVAIL. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 25 53 20 50 24 / 0 0 0 10 40 TULIA 28 57 26 51 26 / 20 0 0 10 40 PLAINVIEW 29 58 24 54 26 / 20 0 0 0 40 LEVELLAND 29 59 24 57 24 / 0 0 0 0 20 LUBBOCK 31 59 24 57 27 / 20 0 0 0 20 DENVER CITY 25 59 29 58 30 / 0 0 0 0 20 BROWNFIELD 29 60 24 59 28 / 10 0 0 0 20 CHILDRESS 36 65 26 56 27 / 60 0 0 0 40 SPUR 36 64 29 59 31 / 40 0 0 0 20 ASPERMONT 40 66 30 62 36 / 50 0 0 0 20 && .LUB WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 8 PM CST THIS EVENING FOR THE FOLLOWING ZONES: TXZ023-028-029-033>035-039-040. HIGH WIND WARNING UNTIL 8 PM CST THIS EVENING FOR THE FOLLOWING ZONES: TXZ021-022-027. && $$ 16/26
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1143 AM CST SAT FEB 9 2013 .UPDATE... CONVECTIVE FORECAST APPEARS LARGELY ON TRACK FOR THIS AFTERNOON. WHILE DEWPOINTS ACROSS THE ROLLING PLAINS ARE STILL SOMEWHAT LOW... IN THE UPPER 30S FOR THE MOST PART... MOISTURE HAS BEEN RAPIDLY INCREASING THROUGHOUT THE MORNING. LOW LEVEL WINDS ARE ON THE RISE AS WELL...MOST IMPORTANTLY UPSTREAM OF THE CWA WHERE DEWPOINTS IN CENTRAL TEXAS ARE CURRENTLY IN THE UPPER 40S TO NEAR 50S. IN ADDITION...LATEST RUC GUIDANCE INDICATES SLIGHTLY MORE SUBSTANTIAL MOISTURE RETURN THAN IN PREVIOUS RUNS...BRINGING LOW 50S DEWPOINTS TO THE ROLLING PLAINS BY 21/22Z. THIS IS RESULTING IN MORE BULLISH INSTABILITY PROGS... WITH MLCAPE VALUES APPROACHING 1000 J/KG BETWEEN 21 AND 03Z. FURTHERMORE... MODEL QPF FIELDS ARE TRENDING TOWARDS SLIGHTLY EARLIER INITIATION...MOSTLY BETWEEN LBB AND THE SOUTHERN PANHANDLE. INITIATION THIS EARLY WOULD VERY LIKELY RESULT IN SUPERCELLS GIVEN THE STRENGTH AND NATURE OF AMBIENT WIND FIELDS... INCLUDING BULK SHEAR VECTORS ALIGNED NEARLY PERPENDICULAR TO THE INITIATING BOUNDARY. FURTHER SOUTHEAST...A STRONGER CAP WILL LIKELY PROHIBIT INITIATION FROM OCCURRING UNTIL THE PACIFIC FRONT SWEEPS THROUGH THE AREA AFTER 00Z. THUS... EXTENDED POPS A BIT TO THE WEST IN THE NORTHERN PORTION OF THE CWA TO BETTER REFLECT ANTICIPATED EARLIER INITIATION... AND LIKEWISE LOWER POPS IN THE SOUTHEAST EARLIER IN THE AFTERNOON && .AVIATION.. VERY DIFFERENT SCENARIOS AT EACH TERMINAL TODAY. AT LBB...WINDS WILL PICK UP DURING THE AFTERNOON...RESULTING IN SOME PATCHY BLOWING DUST. AT CDS...THUNDERSTORMS ARE EXPECTED TO DEVELOP TO THE WEST OF THE TERMINAL AND MOVE EAST BETWEEN 23-02Z... AND POSSIBLY LATER. VFR CONDITIONS WILL PREVAIL AFTER 05Z AT CDS. && .PREV DISCUSSION... /ISSUED 549 AM CST SAT FEB 9 2013/ AVIATION... TODAY WILL NOT BE A PLEASANT FLYING DAY IN THE VICINITY OF KLBB. STRONG WINDS NEAR 45KT OUT OF THE SOUTH WERE OBSERVED JUST OFF THE DECK NEAR KLBB. LATE THIS MORNING SURFACE WINDS WILL GREATLY INCREASE OUT OF THE SOUTHWEST AT BOTH TAF SITES BUT ESPECIALLY AT KLBB. SUSTAINED WINDS NEAR 30KT ARE POSSIBLE WITH LIGHT VISIBILITY RESTRICTIONS DUE TO BLOWING DUST. A DRYLINE WILL BE LOCATED BETWEEN KLBB AND KCDS WHICH WILL CREATE A CHANCE OF THUNDERSTORMS NEAR KCDS EARLY IN THE EVENING. AS THIS POWERFUL STORM SYSTEM MOVES JUST NORTH OF THE AREA...A FRONT WILL SWEEP INTO THE REGION SHIFTING WINDS TO THE WEST AT BOTH TAF SITES THIS EVENING. WINDS WILL STILL REMAIN BREEZY THROUGHOUT THE NIGHT. PREV DISCUSSION... /ISSUED 453 AM CST SAT FEB 9 2013/ SHORT TERM... TODAYS FORECAST IS QUITE A DOOZY. LOW LEVEL MOISTURE WAS MUCH SLOWER TO MAKE ITS WAY BACK TO THE REGION THIS MORNING DESPITE SOUTHEASTERLY UPSLOPE LOW LEVEL WINDS. HIGH CLOUDS THIS MORNING ARE EXPECTED TO SWEEP OFF TO THE EAST WITH PERHAPS SOME STILL LINGERING OVER THE ROLLING PLAINS BY THIS AFTERNOON. THERE SHOULD NOT BE AS MUCH INHIBITING OF DEEP MIXING THIS AFTERNOON WITH THE LACK OF CLOUD COVER. RAPID SURFACE CYCLOGENESIS IN LEE OF THE ROCKIES WILL DEVELOP IN RESPONSE TO AN APPROACHING STORM SYSTEM TO AFFECT A LARGE PORTION OF THE COUNTRY. MODELS HAVE BEEN CONSISTENT IN DEPICTING A 100KT MAXIMUM AT 500HPA FROM EAST CENTRAL NEW MEXICO THROUGH THE WESTERN TEXAS PANHANDLE. A BROAD AREA OF 40-50KT WINDS WILL ENCOMPASS MUCH OF THE REGION AROUND 700HPA. A LOW LEVEL JET CURRENTLY OVER THE AREA WILL LEAD TO QUICK MIXING OF STRONG WINDS DOWN TO THE SURFACE AFTER SUNRISE. THE STRONG UPPER LEVEL JET MAXIMA WILL NOT COME ACROSS UNTIL LATE TONIGHT INTO SUNDAY. SOLID ADVISORY LEVEL WINDS CAN BE EXPECTED FOR MOST AREAS ON THE CAPROCK ALONG WITH VISIBILITY RESTRICTIONS DUE TO BLOWING DUST. A PACIFIC FRONT WILL COME SWEEPING THROUGH THE AREA THIS EVENING BRINGING MUCH DRIER AND COOLER AIR. EARLY THIS MORNING...A WEAK SHORTWAVE WAS MOVING NORTHEAST THROUGH THE FLOW OVER THE ROLLING PLAINS. THIS WAS GENERATING SOME MID LEVEL CLOUDS AND RADAR RETURNS. HOWEVER...GIVEN THE VERY DRY LOW LEVELS...DO NOT THINK MUCH WILL BE ABLE TO REACH THE GROUND. THIS DAY WOULD NOT BE COMPLETE WITHOUT A THREAT FOR SEVERE WEATHER WHICH WILL MAKE IT FEEL LIKE A NORMAL WEST TEXAS SPRING DAY. STORM DEVELOPMENT CAN BE EXPECTED LATE IN THE DAY WITH HIGHEST CHANCES OVER THE ROLLING PLAINS. MAXIMUM HEIGHT FALLS WILL BE NORTH OF THE REGION ACROSS THE CENTRAL PLAINS. HOWEVER...STRONG FRONTOGENETICAL FORCING WILL ENTER THE REGION AS THE PACIFIC FRONT SWEEPS THROUGH THE AREA THIS EVENING. A LOW LEVEL JET WILL AGAIN FORM OUT AHEAD OF THE FRONT THIS EVENING ADDING TO THE LOW LEVEL LIFT. THERE WILL BE MODEST INSTABILITIES OF 500-1000 J/KG AS THE SURFACE DEW POINT SURGES TO AROUND 50 DEGREES OFF THE CAPROCK. INITIALLY...CONVECTION WILL BE CAPPED AT THE SURFACE AND MAY ONLY SEE A BRIEF PERIOD OF AN UNCAPPED ENVIRONMENT CLOSE TO 23Z. AS STRONGER LOW LEVEL LIFT MOVES INTO THE AREA STORMS MAY BE ABLE TO BLOSSOM NEAR SUNSET. STORMS WILL ALSO BE TRANSITIONING FROM SURFACE BASED TO ELEVATED. REGARDING THE TYPE OF SEVERE THREAT...SUPERCELLS ARE EXPECTED WITH VERY STRONG SHEAR. THERE IS GOOD CLOCKWISE LOW LEVEL TURNING IN THE HODOGRAPHS BUT ADDITIONAL INSTABILITY AND A LONGER PERIOD OF SURFACE BASED STORMS WOULD BE DESIRABLE FOR MORE OF A TORNADO THREAT. HELICITY VALUES ARE THEREFORE VERY IMPRESSIVE OVER THE ROLLING PLAINS. OTHERWISE...HAIL AND DAMAGING WINDS CAN BE ANTICIPATED OUT OF STORMS THAT DEVELOP. A STRONG WIND GUST MAY BE MORE LIKELY GIVEN THE VERY STRONG WINDS THAT WILL OCCUR TODAY. STORMS THAT DO DEVELOP THIS AFTERNOON AND EVENING WILL LIKELY BE HAULING LIKE A MACK TRUCK. JDV LONG TERM... HEIGHT GRADIENT AND WIND FIELDS WILL REMAIN FAIRLY TIGHT ACROSS THE TEXAS SOUTH PLAINS SUNDAY AS THE UPPER LOW DEEPENS HEADING INTO THE NORTHERN MISSISSIPPI VALLEY AND A TRAILING DISTURBANCE DROPS SOUTHWARD INTO THE 4-CORNERS. SUNDAY EXPECTED TO BE COOLER BEHIND THE PACIFIC COLD FRONT...THOUGH THIS MAY BE SOMEWHAT OFFSET BY THE DOWNSLOPE WIND COMPONENT...ESPECIALLY OVER THE ROLLING PLAINS. WINDS SHOULD DIMINISH SOMEWHAT HEADING INTO THE AFTERNOON...THOUGH APPEAR STRONG ENOUGH TO SUPPORT A MENTION OF AT LEAST PATCHY BLOWING DUST ON THE CAP-ROCK. FLOW SHOULD BACK INTO MONDAY AS UPPER TROUGH SWINGS THROUGH THE SOUTHERN ROCKIES AND DEEPENS VERY SLIGHTLY. A SHALLOW COLD AIRMASS WILL ATTEMPT TO DROP INTO THE AREA EARLY MONDAY BUT WILL BE UP AGAINST RENEWED LEE-SIDE CYCLOGENESIS OVER THE SOUTHWESTERN PART OF THE TEXAS SOUTH PLAINS. A FAIRLY STRONG SOUTH TO NORTH TEMPERATURE GRADIENT SHOULD SET UP...LOW LEVEL FLOW WILL EVENTUALLY BACK MORE TO THE EAST LATE ON MONDAY ALTHOUGH MOISTURE RETURN INITIALLY WILL BE LITTLE OR NONE. THE UPPER TROUGH IS EXPECTED TO PROGRESS EASTWARD ACROSS THE EXTREME SOUTHERN PART OF THE TEXAS PANHANDLE EARLY TUESDAY... FILLING SLIGHTLY ALONG THE WAY. WE ARE EXPECTING ONLY A MODEST LOW LEVEL MOISTURE RETURN THOUGH THIS WILL TEND TO POOL ALONG A FRONTOGENETIC ZONE ACROSS THE SOUTHERN PANHANDLE. THE AIRMASS WILL COOL QUICKLY AS THE UPPER TROUGH SWINGS OVERHEAD...AND ANY SHOWERS SHOULD TEND TO FAVOR SNOW PHASE ON THE CAPROCK...AND EVEN PERHAPS A MIXTURE FOR THE ROLLING PLAINS. BUT PRECIPITATION TOTALS CURRENTLY DO NOT SUPPORT CONSIDERATION OF ANY TYPE OF WINTER WEATHER WATCH OR ADVISORY. WEAKENING NORTHWEST FLOW WEDNESDAY WILL BE FOLLOWED BY BACKING FLOW AGAIN AS ANOTHER DISTURBANCE DIGS SOUTHWARD OUT OF WESTERN CANADA THURSDAY AND FRIDAY. MODEL DISPARITY INCREASES QUITE A BIT BY THIS TIME SO CONFIDENCE ON AMPLITUDE OF ANY WAVES LATE NEXT WEEK IS LOW. SOME DISCREPANCY AS WELL WITH ARRIVAL OF NEXT CANADIAN COLD FRONT BETWEEN EARLY AND LATE THURSDAY. WE USED A BLEND OF ECMWF AND GFS SOLUTIONS FOR THIS PERIOD WHICH WAS STILL REASONABLY CLOSE TO THE PREVIOUS FORECAST. FRIDAY WOULD SEE THE COLDEST DAY OF THE COMING WEEK IF THESE TRENDS PAN OUT. RMCQUEEN FIRE WEATHER... THE WILDFIRE THREAT MAY NOT HAVE BEEN AS INTENSE AS PREVIOUSLY THOUGHT. NEAR SURFACE MOISTURE IS STILL EXPECTED TO INCREASE THIS MORNING WHICH WILL RESULT IN HIGHER RELATIVE HUMIDITY VALUES THIS AFTERNOON. AS TEMPERATURES INCREASE...AFTERNOON RELATIVE HUMIDITY VALUES WILL DROP TO RIGHT AROUND 15 PERCENT IN THE SOUTHWESTERN TEXAS PANHANDLE WITH HIGHER VALUES ELSEWHERE. WINDS ARE EXPECTED TO BE VERY STRONG WITH A RAPIDLY DEVELOPING STORM SYSTEM OVER THE ROCKIES. WHAT REMAINS OF HIGH UNCERTAINTY IS THE EFFECT OF A LOW LEVEL THERMAL RIDGE. THIS THERMAL RIDGE WILL HAVE ITS AXIS CENTERED OVER THE WESTERN SOUTH PLAINS UP THROUGH THE WESTERN TEXAS PANHANDLE. THE 500MB WINDS WILL BE SLIGHTLY OUT OF POSITION BUT DO HAVE SOME OVERLAP NEAR THE WESTERN SOUTH PLAINS. THIS WILL BE THE FIRST TIME THIS SEASON WE WILL SEE THE MAXIMUM MID LEVEL WINDS NEAR THE LOW LEVEL THERMAL RIDGE. THE DROUGHT HAS ALSO BEEN THE WORST IN THE WESTERN SOUTH PLAINS THROUGH THE SOUTHWESTERN TEXAS PANHANDLE. HOWEVER...FUELS ARE STILL NEAR NORMAL MOISTURE LEVELS AND WILL CANCEL THE FIRE WEATHER WATCH BECAUSE OF THIS. SUNDAY WILL SEE A MODERATELY WINDY DAY WITH DRY WESTERLY DOWNSLOPE WINDS. COOLER TEMPERATURES SHOULD KEEP THE AFTERNOON RELATIVE HUMIDITY JUST ABOVE 15 PERCENT ON THE CAPROCK...BUT THE ENHANCED DOWNSLOPE FLOW OVER THE SOUTHERN PART OF THE ROLLING PLAINS IN PARTICULAR MIGHT BRING ON LOCALLY CRITICAL CONDITIONS. FUELS IN THIS AREA...HOWEVER...STILL APPEAR FAIRLY NON-RESPONSIVE WITH ONLY MODEST ERC LEVELS AND ALSO KEETCH-BYRAM INDICES NEAR NORMAL RANGES. WOULD THUS LIKELY FAVOR MORE AN ENHANCED FIRE WEATHER THREAT ON SUNDAY THAN A CRITICAL AREA. MONDAY ALSO OFFERS AT LEAST A MENTION FOR AN ENHANCED THREAT OF FIRE WEATHER CONDITIONS OVER THE SOUTHWESTERN SOUTH PLAINS WITH A WEAK LOW LEVEL THERMAL RIDGE AND TIGHT ENOUGH SURFACE GRADIENT FOR MODERATE SOUTHWEST BREEZES. RMCQUEEN && .PRELIMINARY POINT TEMPS/POPS... FRIONA 24 55 19 49 21 / 0 0 0 10 40 TULIA 25 57 22 48 24 / 20 0 0 10 40 PLAINVIEW 28 57 22 51 25 / 20 0 0 0 40 LEVELLAND 28 57 22 57 25 / 0 0 0 0 20 LUBBOCK 29 58 22 56 26 / 20 0 0 0 20 DENVER CITY 28 57 24 58 26 / 0 0 0 0 20 BROWNFIELD 29 58 24 57 26 / 10 0 0 0 20 CHILDRESS 36 63 25 52 28 / 60 0 0 0 40 SPUR 34 61 25 56 28 / 40 0 0 0 20 ASPERMONT 41 65 27 60 30 / 50 0 0 0 20 && .LUB WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 8 PM CST THIS EVENING FOR THE FOLLOWING ZONES: TXZ021>023-027>029-033>035-039-040. && $$ 16/99/99
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1137 AM CST SAT FEB 9 2013 .AVIATION... CONCERNS...STRONG TO SEVERE CONVECTION LATE TONIGHT AND TRANSITION OF MVFR TO IFR THIS EVENING. WARM...MOIST ADVECTION IS IN PROGRESS NOW AND WILL CONTINUE THROUGH LATE TONIGHT. CEILINGS WILL REMAIN MVFR THIS AFTERNOON THEN GO IFR THIS EVENING THROUGH LATE TONIGHT AHEAD OF AN APPROACHING PACIFIC FRONT/DRYLINE. WE COULD SEE AN HOUR OR TWO OF CEILINGS ABOVE 3000 FEET LATE THIS AFTERNOON...BUT THIS WILL BE SHORT LIVED. WILL INCLUDE VCSH FOR THE SOME OF THE EVENING HOURS AND SOME OF THIS ACTIVITY MAY PASS ACROSS THE AIRPORTS WITH VISIBILITIES FALLING TO IFR DURING THE EVENT. CONVECTION WILL BE DEVELOPING WEST OF THE REGION ALONG THE COLD FRONT THIS EVENING AND WILL PUSH RAPIDLY THROUGH KFTW/KAFW AROUND 10Z AND KDFW...KDAL AND KACT 10 TO 11Z. SEVERE THUNDERSTORMS ARE POSSIBLE WITH LARGE HAIL AND DAMAGING STRAIGHT LINE WINDS POSSIBLY AFFECTING ANY OF OUR TAF SITES BETWEEN 10-12Z. WINDS WILL BE SOUTHERLY AND GUSTY THIS AFTERNOON THEN 10-15KTS OVERNIGHT. AFTER THE COLD FRONT PASSES...CEILINGS WILL LIFT TO VFR AND WINDS WILL VEER WESTERLY AND INCREASE TO 15-20KTS. 75 && .UPDATE... WIDELY SCATTERED SHOWERS HAD DEVELOPED THIS MORNING ACROSS PARTS OF NORTH TEXAS...WITH MOST OF THE ACTIVITY CONCENTRATED IN AREAS NORTH THROUGH NORTHEAST OF DFW METROPLEX. WILL CONTINUE WITH SLIGHT CHANCES OF SHOWERS AREA WIDE THIS AFTERNOON AS WARM/MOIST ADVECTION INTENSIFIES. WARM FRONT WAS BECOMING BETTER DEFINED FROM SOUTH OF LUBBOCK TO NEAR HOUSTON AT MID MORNING. THIS WARM FRONT WILL CONTINUE TO MOVE/DEVELOP NORTHWARD TODAY...AND ACCELERATE NORTHWARD INTO OKLAHOMA LATE TONIGHT AS LOW LEVEL SOUTHERLY WINDS INCREASE. TEMPERATURES THIS AFTERNOON WILL CONTINUE TO SLOWLY RISE IN SPITE OF WIDESPREAD CLOUD COVER AS WARM FRONT LIFTS THROUGH THE AREA. TEMPERATURES LIKELY TO HOLD STEADY OR EVEN CONTINUE TO SLOWLY RISE INTO THE EVENING HOURS AS LOW LEVEL WARM/MOIST ADVECTION CONTINUES. STRONG UPPER SYSTEM CENTERED OVER ARIZONA THIS MORNING WILL MOVE EAST AND THEN NORTHEAST OUT OF THE SOUTHERN ROCKIES TONIGHT. A PACIFIC FRONT WILL OVERTAKE THE DEVELOPING DRYLINE ACROSS WESTERN TEXAS TONIGHT...AND THEN ACCELERATE EASTWARD TONIGHT. THE PACIFIC COLD FRONT IS EXPECTED TO BE THE PRIMARY FOCUS FOR THE WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS NORTH TEXAS LATER TONIGHT. CURRENT TRENDS OBSERVED ON LATEST ANALYSES MATCH WELL WITH THE EXPECTED EVOLUTION OF CONVECTION FOR LATER TONIGHT. STRONG TO SEVERE STORMS...WITH A POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL...REMAIN IN THE FORECAST FOR LATE TONIGHT AND EARLY SUNDAY MORNING. 09/GP && .PREV DISCUSSION... /ISSUED 429 AM CST SAT FEB 9 2013/ UPPER LEVEL TROUGH OVER THE GREAT BASIN WILL MARCH EAST TODAY AND EJECT NORTHEASTWARD OUT INTO THE PLAINS TONIGHT AND SUNDAY. AHEAD OF THE APPROACHING TROUGH...STRONG SOUTHERLY FLOW OVER NORTH TEXAS WILL RESULT IN INCREASING MOISTURE AND CLOUDS TODAY. DUE TO PRONOUNCED SOUTHWEST FLOW BETWEEN 700-800MB OFF OF THE HIGHER TERRAIN OF MEXICO...A STRONG CAPPING INVERSION WILL BE IN PLACE OVER NORTH TEXAS THROUGH THIS EVENING. MODEL SOUNDINGS DO INDICATE THE PRESENCE OF WEAK CONVECTIVE INSTABILITY AND SATURATION ABOVE THE INVERSION NEAR AND ABOVE 12000FT. MOST OF THIS PRECIPITATION WILL EVAPORATE BEFORE HITTING THE GROUND...SO RADARS WILL BE A BIT DECEIVING TODAY. THIS ELEVATED CONVECTION PROBABLY WILL NOT BE INTENSE ENOUGH FOR ANY THUNDER...AND LITTLE TO NO MEASURABLE RAIN IS EXPECTED. WILL CARRY JUST A SLIGHT CHANCE OF SHOWERS TODAY. AS THE SOUTHERN EDGE OF THE UPPER TROUGH AXIS SWEEPS ACROSS TEXAS TONIGHT...STRONG FORCING WILL RAPIDLY LIFT AND ERODE THE CAP. MEANWHILE A NORTH-SOUTH ORIENTED PACIFIC FRONT WILL MOVE INTO THE AREA FROM THE WEST AFTER MIDNIGHT. SINCE THE AIRMASS WILL BE UNCAPPED AND CONTAIN LOW LEVEL INSTABILITY ../WITH PARCELS IN THE LOWEST KM CONTAINING CAPE ON THE ORDER OF 500 J/KG ACROSS THE NORTH AND 1500 J/KG ACROSS THE SOUTH/.. A LINE OF CONVECTION SHOULD DEVELOP ALONG THE FRONT. DEEP LAYER SHEAR WILL BE MORE THAN ADEQUATE FOR SEVERE WEATHER. GUIDANCE CONTINUES TO INDICATE A RAPID VEERING/WEAKENING OF THE LOW LEVEL SHEAR PROFILE JUST AHEAD OF THE FRONT. THUS THE TORNADO THREAT APPEARS TO BE LIMITED...AND THE PRIMARY SEVERE THREAT WILL BE DAMAGING WINDS AND HAIL. THERE IS A BIT OF UNCERTAINTY REGARDING THE TIMING OF THE LINE OF STORMS. I AM CONCERNED THAT WITH THE UPPER LEVEL SYSTEM CURVING OFF TO THE NORTHEAST AND LITTLE TO NO PRESSURE RISES/COLD AIR BEHIND THE FRONT...THE FRONT/SQUALL LINE MAY SLOW DOWN AS IT MOVES ACROSS THE CWA. SOME OF THE HIGH-RES GUIDANCE IS INDICATING A SLOWER PROGRESSION...AND THE RAP AT 18HRS HAS THE FRONT A BIT FARTHER TO THE WEST THAN THE MEDIUM RANGE MODELS. WILL SLOW THE TIMING DOWN A BIT FROM PREVIOUS FORECASTS...WHICH WILL RESULT IN INCREASING THE POPS AFTER 12Z SUNDAY MAINLY OVER THE EAST. RIGHT NOW EXPECT THE LINE TO REACH THE WESTERN CWA AROUND 1-2AM...AFFECT THE I-35 CORRIDOR AROUND 3-7AM...AND NOT EXIT THE SOUTHEASTERN ZONES UNTIL LATE MORNING TUESDAY. GENERALLY SUNNY SKIES AND VERY DRY AIR WILL ALLOW TEMPS TO REBOUND SUNDAY AFTERNOON INTO THE LOW 70S ACROSS THE CENTRAL/WESTERN ZONES...WITH SLIGHTLY COOLER HIGHS IN THE EAST WHERE THERE WILL BE MORE CLOUDS. MID LEVEL CLOUDS WILL LINGER ACROSS THE SOUTHEAST HALF OF THE CWA INTO MONDAY. LOWS SUNDAY NIGHT WILL BE COOLEST IN THE CLEAR NW ZONES WHERE THEY WILL DROP TO NEAR FREEZING...BUT THEY WILL ONLY BE IN THE UPPER 40S OVER THE SOUTHEAST. ON MONDAY A SHORTWAVE WILL MOVE THROUGH IN SOUTHWEST FLOW ALOFT ACROSS CENTRAL TX...AND WILL SHOW A SLIGHT CHANCE OF SHOWERS IN THE SOUTHEAST. A SECOND UPPER LEVEL TROUGH WILL BE APPROACHING TEXAS ON MONDAY NIGHT WHICH WILL RESULT IN WARM ADVECTION AND ISENTROPIC LIFT OVER NORTH TEXAS. BEST CHANCES OF RAIN OCCUR TUESDAY WHEN A COLD FRONT MOVES THROUGH THE REGION AND STRENGTHENS THE ISENTROPIC LIFT. ACROSS THE NORTHERN ZONES...SURFACE TEMPS MAY GET COLD ENOUGH NEAR THE CORE OF THE UPPER LOW TO SUPPORT A RAIN/SNOW MIX. HOWEVER MODEL GUIDANCE HAS TRENDED THE TRACK OF THE UPPER SYSTEM FARTHER TO THE NORTH. SUCH A TRACK WOULD KEEP THE SNOW POTENTIAL IN OKLAHOMA. COOLER AND DRY WEATHER WILL PREVAIL WEDNESDAY WITH TEMPS NEAR NORMAL. THURSDAY LOOKS WARMER WITH SOUTHERLY WINDS AHEAD OF ANOTHER COLD FRONT THURSDAY NIGHT. TEMPS WILL FALL BELOW NORMAL BEHIND THIS FRONT FOR FRIDAY AND SATURDAY. GFS/ECMWF BOTH HAD PRECIP BEHIND THIS FRONT YESTERDAY BUT THE GFS IS TRENDING DRIER...AND THE 0Z ECMWF IS COMPLETELY DRY. WILL KEEP POPS OUT OF THE FORECAST ON FRIDAY AT THIS TIME. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 63 55 72 41 65 / 20 90 30 5 10 WACO, TX 64 57 74 43 68 / 20 80 50 10 20 PARIS, TX 59 54 68 38 62 / 20 80 60 5 10 DENTON, TX 61 53 71 35 64 / 20 90 30 5 10 MCKINNEY, TX 61 55 70 34 64 / 20 90 40 5 10 DALLAS, TX 63 56 72 43 65 / 20 90 40 5 10 TERRELL, TX 63 57 71 41 65 / 20 80 60 5 10 CORSICANA, TX 64 59 71 45 65 / 20 70 70 10 20 TEMPLE, TX 65 58 74 44 69 / 20 70 60 10 20 MINERAL WELLS, TX 63 50 72 35 67 / 20 90 20 5 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 75/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1105 AM CST SAT FEB 9 2013 .UPDATE... WIDELY SCATTERED SHOWERS HAD DEVELOPED THIS MORNING ACROSS PARTS OF NORTH TEXAS...WITH MOST OF THE ACTIVITY CONCENTRATED IN AREAS NORTH THROUGH NORTHEAST OF DFW METROPLEX. WILL CONTINUE WITH SLIGHT CHANCES OF SHOWERS AREA WIDE THIS AFTERNOON AS WARM/MOIST ADVECTION INTENSIFIES. WARM FRONT WAS BECOMING BETTER DEFINED FROM SOUTH OF LUBBOCK TO NEAR HOUSTON AT MID MORNING. THIS WARM FRONT WILL CONTINUE TO MOVE/DEVELOP NORTHWARD TODAY...AND ACCELERATE NORTHWARD INTO OKLAHOMA LATE TONIGHT AS LOW LEVEL SOUTHERLY WINDS INCREASE. TEMPERATURES THIS AFTERNOON WILL CONTINUE TO SLOWLY RISE IN SPITE OF WIDESPREAD CLOUD COVER AS WARM FRONT LIFTS THROUGH THE AREA. TEMPERATURES LIKELY TO HOLD STEADY OR EVEN CONTINUE TO SLOWLY RISE INTO THE EVENING HOURS AS LOW LEVEL WARM/MOIST ADVECTION CONTINUES. STRONG UPPER SYSTEM CENTERED OVER ARIZONA THIS MORNING WILL MOVE EAST AND THEN NORTHEAST OUT OF THE SOUTHERN ROCKIES TONIGHT. A PACIFIC FRONT WILL OVERTAKE THE DEVELOPING DRYLINE ACROSS WESTERN TEXAS TONIGHT...AND THEN ACCELERATE EASTWARD TONIGHT. THE PACIFIC COLD FRONT IS EXPECTED TO BE THE PRIMARY FOCUS FOR THE WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS NORTH TEXAS LATER TONIGHT. CURRENT TRENDS OBSERVED ON LATEST ANALYSES MATCH WELL WITH THE EXPECTED EVOLUTION OF CONVECTION FOR LATER TONIGHT. STRONG TO SEVERE STORMS...WITH A POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL...REMAIN IN THE FORECAST FOR LATE TONIGHT AND EARLY SUNDAY MORNING. 09/GP && .AVIATION... /12Z TAFS/ CONCERNS...MVFR CEILINGS THIS MORNING...STORMS TONIGHT. MOISTURE RETURN CONTINUES. FWD RAOB AND VWP DATA SHOW LLJ OF 30-35KTS...BUT MVFR CEILINGS ARE ONLY SPOTTY AT TAF ISSUANCE TIME. EXPECT THE LAYER INVOF 2KFT AGL WILL BECOME MORE SOLID AS THE MORNING PROGRESSES...GRADUALLY LIFTING INTO THE AFTERNOON. EXPECT ANY SCATTERING WILL BE TEMPORARY AS SURFACE HEATING SIMPLY REINFORCES THE STRATOCU LAYER. SURFACE WINDS WILL INCREASE IN ADVANCE OF AN APPROACHING STORM SYSTEM. SATURATED ISENTROPIC UPGLIDE WILL RESULT IN SOME -RA/-SHRA AS EARLY AS THIS EVENING. ALTHOUGH THE MAIN MID-LEVEL ENERGY WILL BE WELL NORTH...AN ASSOCIATED SURFACE FRONT WILL BE DRAGGED WEST TO EAST THROUGH THE REGION LATE TONIGHT THROUGH SUNDAY MORNING. THE FRONT WILL BE PRECEDED BY A SQUALL LINE WITH POTENTIALLY SEVERE STORMS. THE 12Z TAFS DELAY THE EARLIEST ARRIVAL OF THE SIGNIFICANT CONVECTION UNTIL 09Z (3 AM CST). THE ORIENTATION OF THE FLOW ALOFT IS SUCH THAT THE LINE OF STORMS MAY NOT REACH THE TAF SITES UNTIL AS LATE AS 12Z (6 AM CST). 25 && .PREV DISCUSSION... /ISSUED 429 AM CST SAT FEB 9 2013/ UPPER LEVEL TROUGH OVER THE GREAT BASIN WILL MARCH EAST TODAY AND EJECT NORTHEASTWARD OUT INTO THE PLAINS TONIGHT AND SUNDAY. AHEAD OF THE APPROACHING TROUGH...STRONG SOUTHERLY FLOW OVER NORTH TEXAS WILL RESULT IN INCREASING MOISTURE AND CLOUDS TODAY. DUE TO PRONOUNCED SOUTHWEST FLOW BETWEEN 700-800MB OFF OF THE HIGHER TERRAIN OF MEXICO...A STRONG CAPPING INVERSION WILL BE IN PLACE OVER NORTH TEXAS THROUGH THIS EVENING. MODEL SOUNDINGS DO INDICATE THE PRESENCE OF WEAK CONVECTIVE INSTABILITY AND SATURATION ABOVE THE INVERSION NEAR AND ABOVE 12000FT. MOST OF THIS PRECIPITATION WILL EVAPORATE BEFORE HITTING THE GROUND...SO RADARS WILL BE A BIT DECEIVING TODAY. THIS ELEVATED CONVECTION PROBABLY WILL NOT BE INTENSE ENOUGH FOR ANY THUNDER...AND LITTLE TO NO MEASURABLE RAIN IS EXPECTED. WILL CARRY JUST A SLIGHT CHANCE OF SHOWERS TODAY. AS THE SOUTHERN EDGE OF THE UPPER TROUGH AXIS SWEEPS ACROSS TEXAS TONIGHT...STRONG FORCING WILL RAPIDLY LIFT AND ERODE THE CAP. MEANWHILE A NORTH-SOUTH ORIENTED PACIFIC FRONT WILL MOVE INTO THE AREA FROM THE WEST AFTER MIDNIGHT. SINCE THE AIRMASS WILL BE UNCAPPED AND CONTAIN LOW LEVEL INSTABILITY ../WITH PARCELS IN THE LOWEST KM CONTAINING CAPE ON THE ORDER OF 500 J/KG ACROSS THE NORTH AND 1500 J/KG ACROSS THE SOUTH/.. A LINE OF CONVECTION SHOULD DEVELOP ALONG THE FRONT. DEEP LAYER SHEAR WILL BE MORE THAN ADEQUATE FOR SEVERE WEATHER. GUIDANCE CONTINUES TO INDICATE A RAPID VEERING/WEAKENING OF THE LOW LEVEL SHEAR PROFILE JUST AHEAD OF THE FRONT. THUS THE TORNADO THREAT APPEARS TO BE LIMITED...AND THE PRIMARY SEVERE THREAT WILL BE DAMAGING WINDS AND HAIL. THERE IS A BIT OF UNCERTAINTY REGARDING THE TIMING OF THE LINE OF STORMS. I AM CONCERNED THAT WITH THE UPPER LEVEL SYSTEM CURVING OFF TO THE NORTHEAST AND LITTLE TO NO PRESSURE RISES/COLD AIR BEHIND THE FRONT...THE FRONT/SQUALL LINE MAY SLOW DOWN AS IT MOVES ACROSS THE CWA. SOME OF THE HIGH-RES GUIDANCE IS INDICATING A SLOWER PROGRESSION...AND THE RAP AT 18HRS HAS THE FRONT A BIT FARTHER TO THE WEST THAN THE MEDIUM RANGE MODELS. WILL SLOW THE TIMING DOWN A BIT FROM PREVIOUS FORECASTS...WHICH WILL RESULT IN INCREASING THE POPS AFTER 12Z SUNDAY MAINLY OVER THE EAST. RIGHT NOW EXPECT THE LINE TO REACH THE WESTERN CWA AROUND 1-2AM...AFFECT THE I-35 CORRIDOR AROUND 3-7AM...AND NOT EXIT THE SOUTHEASTERN ZONES UNTIL LATE MORNING TUESDAY. GENERALLY SUNNY SKIES AND VERY DRY AIR WILL ALLOW TEMPS TO REBOUND SUNDAY AFTERNOON INTO THE LOW 70S ACROSS THE CENTRAL/WESTERN ZONES...WITH SLIGHTLY COOLER HIGHS IN THE EAST WHERE THERE WILL BE MORE CLOUDS. MID LEVEL CLOUDS WILL LINGER ACROSS THE SOUTHEAST HALF OF THE CWA INTO MONDAY. LOWS SUNDAY NIGHT WILL BE COOLEST IN THE CLEAR NW ZONES WHERE THEY WILL DROP TO NEAR FREEZING...BUT THEY WILL ONLY BE IN THE UPPER 40S OVER THE SOUTHEAST. ON MONDAY A SHORTWAVE WILL MOVE THROUGH IN SOUTHWEST FLOW ALOFT ACROSS CENTRAL TX...AND WILL SHOW A SLIGHT CHANCE OF SHOWERS IN THE SOUTHEAST. A SECOND UPPER LEVEL TROUGH WILL BE APPROACHING TEXAS ON MONDAY NIGHT WHICH WILL RESULT IN WARM ADVECTION AND ISENTROPIC LIFT OVER NORTH TEXAS. BEST CHANCES OF RAIN OCCUR TUESDAY WHEN A COLD FRONT MOVES THROUGH THE REGION AND STRENGTHENS THE ISENTROPIC LIFT. ACROSS THE NORTHERN ZONES...SURFACE TEMPS MAY GET COLD ENOUGH NEAR THE CORE OF THE UPPER LOW TO SUPPORT A RAIN/SNOW MIX. HOWEVER MODEL GUIDANCE HAS TRENDED THE TRACK OF THE UPPER SYSTEM FARTHER TO THE NORTH. SUCH A TRACK WOULD KEEP THE SNOW POTENTIAL IN OKLAHOMA. COOLER AND DRY WEATHER WILL PREVAIL WEDNESDAY WITH TEMPS NEAR NORMAL. THURSDAY LOOKS WARMER WITH SOUTHERLY WINDS AHEAD OF ANOTHER COLD FRONT THURSDAY NIGHT. TEMPS WILL FALL BELOW NORMAL BEHIND THIS FRONT FOR FRIDAY AND SATURDAY. GFS/ECMWF BOTH HAD PRECIP BEHIND THIS FRONT YESTERDAY BUT THE GFS IS TRENDING DRIER...AND THE 0Z ECMWF IS COMPLETELY DRY. WILL KEEP POPS OUT OF THE FORECAST ON FRIDAY AT THIS TIME. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 63 55 72 41 65 / 20 90 30 5 10 WACO, TX 64 57 74 43 68 / 20 80 50 10 20 PARIS, TX 59 54 68 38 62 / 20 80 60 5 10 DENTON, TX 61 53 71 35 64 / 20 90 30 5 10 MCKINNEY, TX 61 55 70 34 64 / 20 90 40 5 10 DALLAS, TX 63 56 72 43 65 / 20 90 40 5 10 TERRELL, TX 63 57 71 41 65 / 20 80 60 5 10 CORSICANA, TX 64 59 71 45 65 / 20 70 70 10 20 TEMPLE, TX 65 58 74 44 69 / 20 70 60 10 20 MINERAL WELLS, TX 63 50 72 35 67 / 20 90 20 5 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /09
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
605 AM CST SAT FEB 9 2013 .AVIATION... /12Z TAFS/ CONCERNS...MVFR CEILINGS THIS MORNING...STORMS TONIGHT. MOISTURE RETURN CONTINUES. FWD RAOB AND VWP DATA SHOW LLJ OF 30-35KTS...BUT MVFR CEILINGS ARE ONLY SPOTTY AT TAF ISSUANCE TIME. EXPECT THE LAYER INVOF 2KFT AGL WILL BECOME MORE SOLID AS THE MORNING PROGRESSES...GRADUALLY LIFTING INTO THE AFTERNOON. EXPECT ANY SCATTERING WILL BE TEMPORARY AS SURFACE HEATING SIMPLY REINFORCES THE STRATOCU LAYER. SURFACE WINDS WILL INCREASE IN ADVANCE OF AN APPROACHING STORM SYSTEM. SATURATED ISENTROPIC UPGLIDE WILL RESULT IN SOME -RA/-SHRA AS EARLY AS THIS EVENING. ALTHOUGH THE MAIN MID-LEVEL ENERGY WILL BE WELL NORTH...AN ASSOCIATED SURFACE FRONT WILL BE DRAGGED WEST TO EAST THROUGH THE REGION LATE TONIGHT THROUGH SUNDAY MORNING. THE FRONT WILL BE PRECEDED BY A SQUALL LINE WITH POTENTIALLY SEVERE STORMS. THE 12Z TAFS DELAY THE EARLIEST ARRIVAL OF THE SIGNIFICANT CONVECTION UNTIL 09Z (3 AM CST). THE ORIENTATION OF THE FLOW ALOFT IS SUCH THAT THE LINE OF STORMS MAY NOT REACH THE TAF SITES UNTIL AS LATE AS 12Z (6 AM CST). 25 && .PREV DISCUSSION... /ISSUED 429 AM CST SAT FEB 9 2013/ UPPER LEVEL TROUGH OVER THE GREAT BASIN WILL MARCH EAST TODAY AND EJECT NORTHEASTWARD OUT INTO THE PLAINS TONIGHT AND SUNDAY. AHEAD OF THE APPROACHING TROUGH...STRONG SOUTHERLY FLOW OVER NORTH TEXAS WILL RESULT IN INCREASING MOISTURE AND CLOUDS TODAY. DUE TO PRONOUNCED SOUTHWEST FLOW BETWEEN 700-800MB OFF OF THE HIGHER TERRAIN OF MEXICO...A STRONG CAPPING INVERSION WILL BE IN PLACE OVER NORTH TEXAS THROUGH THIS EVENING. MODEL SOUNDINGS DO INDICATE THE PRESENCE OF WEAK CONVECTIVE INSTABILITY AND SATURATION ABOVE THE INVERSION NEAR AND ABOVE 12000FT. MOST OF THIS PRECIPITATION WILL EVAPORATE BEFORE HITTING THE GROUND...SO RADARS WILL BE A BIT DECEIVING TODAY. THIS ELEVATED CONVECTION PROBABLY WILL NOT BE INTENSE ENOUGH FOR ANY THUNDER...AND LITTLE TO NO MEASURABLE RAIN IS EXPECTED. WILL CARRY JUST A SLIGHT CHANCE OF SHOWERS TODAY. AS THE SOUTHERN EDGE OF THE UPPER TROUGH AXIS SWEEPS ACROSS TEXAS TONIGHT...STRONG FORCING WILL RAPIDLY LIFT AND ERODE THE CAP. MEANWHILE A NORTH-SOUTH ORIENTED PACIFIC FRONT WILL MOVE INTO THE AREA FROM THE WEST AFTER MIDNIGHT. SINCE THE AIRMASS WILL BE UNCAPPED AND CONTAIN LOW LEVEL INSTABILITY ../WITH PARCELS IN THE LOWEST KM CONTAINING CAPE ON THE ORDER OF 500 J/KG ACROSS THE NORTH AND 1500 J/KG ACROSS THE SOUTH/.. A LINE OF CONVECTION SHOULD DEVELOP ALONG THE FRONT. DEEP LAYER SHEAR WILL BE MORE THAN ADEQUATE FOR SEVERE WEATHER. GUIDANCE CONTINUES TO INDICATE A RAPID VEERING/WEAKENING OF THE LOW LEVEL SHEAR PROFILE JUST AHEAD OF THE FRONT. THUS THE TORNADO THREAT APPEARS TO BE LIMITED...AND THE PRIMARY SEVERE THREAT WILL BE DAMAGING WINDS AND HAIL. THERE IS A BIT OF UNCERTAINTY REGARDING THE TIMING OF THE LINE OF STORMS. I AM CONCERNED THAT WITH THE UPPER LEVEL SYSTEM CURVING OFF TO THE NORTHEAST AND LITTLE TO NO PRESSURE RISES/COLD AIR BEHIND THE FRONT...THE FRONT/SQUALL LINE MAY SLOW DOWN AS IT MOVES ACROSS THE CWA. SOME OF THE HIGH-RES GUIDANCE IS INDICATING A SLOWER PROGRESSION...AND THE RAP AT 18HRS HAS THE FRONT A BIT FARTHER TO THE WEST THAN THE MEDIUM RANGE MODELS. WILL SLOW THE TIMING DOWN A BIT FROM PREVIOUS FORECASTS...WHICH WILL RESULT IN INCREASING THE POPS AFTER 12Z SUNDAY MAINLY OVER THE EAST. RIGHT NOW EXPECT THE LINE TO REACH THE WESTERN CWA AROUND 1-2AM...AFFECT THE I-35 CORRIDOR AROUND 3-7AM...AND NOT EXIT THE SOUTHEASTERN ZONES UNTIL LATE MORNING TUESDAY. GENERALLY SUNNY SKIES AND VERY DRY AIR WILL ALLOW TEMPS TO REBOUND SUNDAY AFTERNOON INTO THE LOW 70S ACROSS THE CENTRAL/WESTERN ZONES...WITH SLIGHTLY COOLER HIGHS IN THE EAST WHERE THERE WILL BE MORE CLOUDS. MID LEVEL CLOUDS WILL LINGER ACROSS THE SOUTHEAST HALF OF THE CWA INTO MONDAY. LOWS SUNDAY NIGHT WILL BE COOLEST IN THE CLEAR NW ZONES WHERE THEY WILL DROP TO NEAR FREEZING...BUT THEY WILL ONLY BE IN THE UPPER 40S OVER THE SOUTHEAST. ON MONDAY A SHORTWAVE WILL MOVE THROUGH IN SOUTHWEST FLOW ALOFT ACROSS CENTRAL TX...AND WILL SHOW A SLIGHT CHANCE OF SHOWERS IN THE SOUTHEAST. A SECOND UPPER LEVEL TROUGH WILL BE APPROACHING TEXAS ON MONDAY NIGHT WHICH WILL RESULT IN WARM ADVECTION AND ISENTROPIC LIFT OVER NORTH TEXAS. BEST CHANCES OF RAIN OCCUR TUESDAY WHEN A COLD FRONT MOVES THROUGH THE REGION AND STRENGTHENS THE ISENTROPIC LIFT. ACROSS THE NORTHERN ZONES...SURFACE TEMPS MAY GET COLD ENOUGH NEAR THE CORE OF THE UPPER LOW TO SUPPORT A RAIN/SNOW MIX. HOWEVER MODEL GUIDANCE HAS TRENDED THE TRACK OF THE UPPER SYSTEM FARTHER TO THE NORTH. SUCH A TRACK WOULD KEEP THE SNOW POTENTIAL IN OKLAHOMA. COOLER AND DRY WEATHER WILL PREVAIL WEDNESDAY WITH TEMPS NEAR NORMAL. THURSDAY LOOKS WARMER WITH SOUTHERLY WINDS AHEAD OF ANOTHER COLD FRONT THURSDAY NIGHT. TEMPS WILL FALL BELOW NORMAL BEHIND THIS FRONT FOR FRIDAY AND SATURDAY. GFS/ECMWF BOTH HAD PRECIP BEHIND THIS FRONT YESTERDAY BUT THE GFS IS TRENDING DRIER...AND THE 0Z ECMWF IS COMPLETELY DRY. WILL KEEP POPS OUT OF THE FORECAST ON FRIDAY AT THIS TIME. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 63 55 72 41 65 / 20 90 30 5 10 WACO, TX 64 57 74 43 68 / 20 80 50 10 20 PARIS, TX 59 54 68 38 62 / 20 80 60 5 10 DENTON, TX 61 53 71 35 64 / 20 90 30 5 10 MCKINNEY, TX 61 55 70 34 64 / 20 90 40 5 10 DALLAS, TX 63 56 72 43 65 / 20 90 40 5 10 TERRELL, TX 63 57 71 41 65 / 20 80 60 5 10 CORSICANA, TX 64 59 71 45 65 / 20 70 70 10 20 TEMPLE, TX 65 58 74 44 69 / 20 70 60 10 20 MINERAL WELLS, TX 63 50 72 35 67 / 20 90 20 5 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 25/92
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
429 AM CST SAT FEB 9 2013 .DISCUSSION... UPPER LEVEL TROUGH OVER THE GREAT BASIN WILL MARCH EAST TODAY AND EJECT NORTHEASTWARD OUT INTO THE PLAINS TONIGHT AND SUNDAY. AHEAD OF THE APPROACHING TROUGH...STRONG SOUTHERLY FLOW OVER NORTH TEXAS WILL RESULT IN INCREASING MOISTURE AND CLOUDS TODAY. DUE TO PRONOUNCED SOUTHWEST FLOW BETWEEN 700-800MB OFF OF THE HIGHER TERRAIN OF MEXICO...A STRONG CAPPING INVERSION WILL BE IN PLACE OVER NORTH TEXAS THROUGH THIS EVENING. MODEL SOUNDINGS DO INDICATE THE PRESENCE OF WEAK CONVECTIVE INSTABILITY AND SATURATION ABOVE THE INVERSION NEAR AND ABOVE 12000FT. MOST OF THIS PRECIPITATION WILL EVAPORATE BEFORE HITTING THE GROUND...SO RADARS WILL BE A BIT DECEIVING TODAY. THIS ELEVATED CONVECTION PROBABLY WILL NOT BE INTENSE ENOUGH FOR ANY THUNDER...AND LITTLE TO NO MEASURABLE RAIN IS EXPECTED. WILL CARRY JUST A SLIGHT CHANCE OF SHOWERS TODAY. AS THE SOUTHERN EDGE OF THE UPPER TROUGH AXIS SWEEPS ACROSS TEXAS TONIGHT...STRONG FORCING WILL RAPIDLY LIFT AND ERODE THE CAP. MEANWHILE A NORTH-SOUTH ORIENTED PACIFIC FRONT WILL MOVE INTO THE AREA FROM THE WEST AFTER MIDNIGHT. SINCE THE AIRMASS WILL BE UNCAPPED AND CONTAIN LOW LEVEL INSTABILITY ../WITH PARCELS IN THE LOWEST KM CONTAINING CAPE ON THE ORDER OF 500 J/KG ACROSS THE NORTH AND 1500 J/KG ACROSS THE SOUTH/.. A LINE OF CONVECTION SHOULD DEVELOP ALONG THE FRONT. DEEP LAYER SHEAR WILL BE MORE THAN ADEQUATE FOR SEVERE WEATHER. GUIDANCE CONTINUES TO INDICATE A RAPID VEERING/WEAKENING OF THE LOW LEVEL SHEAR PROFILE JUST AHEAD OF THE FRONT. THUS THE TORNADO THREAT APPEARS TO BE LIMITED...AND THE PRIMARY SEVERE THREAT WILL BE DAMAGING WINDS AND HAIL. THERE IS A BIT OF UNCERTAINTY REGARDING THE TIMING OF THE LINE OF STORMS. I AM CONCERNED THAT WITH THE UPPER LEVEL SYSTEM CURVING OFF TO THE NORTHEAST AND LITTLE TO NO PRESSURE RISES/COLD AIR BEHIND THE FRONT...THE FRONT/SQUALL LINE MAY SLOW DOWN AS IT MOVES ACROSS THE CWA. SOME OF THE HIGH-RES GUIDANCE IS INDICATING A SLOWER PROGRESSION...AND THE RAP AT 18HRS HAS THE FRONT A BIT FARTHER TO THE WEST THAN THE MEDIUM RANGE MODELS. WILL SLOW THE TIMING DOWN A BIT FROM PREVIOUS FORECASTS...WHICH WILL RESULT IN INCREASING THE POPS AFTER 12Z SUNDAY MAINLY OVER THE EAST. RIGHT NOW EXPECT THE LINE TO REACH THE WESTERN CWA AROUND 1-2AM...AFFECT THE I-35 CORRIDOR AROUND 3-7AM...AND NOT EXIT THE SOUTHEASTERN ZONES UNTIL LATE MORNING TUESDAY. GENERALLY SUNNY SKIES AND VERY DRY AIR WILL ALLOW TEMPS TO REBOUND SUNDAY AFTERNOON INTO THE LOW 70S ACROSS THE CENTRAL/WESTERN ZONES...WITH SLIGHTLY COOLER HIGHS IN THE EAST WHERE THERE WILL BE MORE CLOUDS. MID LEVEL CLOUDS WILL LINGER ACROSS THE SOUTHEAST HALF OF THE CWA INTO MONDAY. LOWS SUNDAY NIGHT WILL BE COOLEST IN THE CLEAR NW ZONES WHERE THEY WILL DROP TO NEAR FREEZING...BUT THEY WILL ONLY BE IN THE UPPER 40S OVER THE SOUTHEAST. ON MONDAY A SHORTWAVE WILL MOVE THROUGH IN SOUTHWEST FLOW ALOFT ACROSS CENTRAL TX...AND WILL SHOW A SLIGHT CHANCE OF SHOWERS IN THE SOUTHEAST. A SECOND UPPER LEVEL TROUGH WILL BE APPROACHING TEXAS ON MONDAY NIGHT WHICH WILL RESULT IN WARM ADVECTION AND ISENTROPIC LIFT OVER NORTH TEXAS. BEST CHANCES OF RAIN OCCUR TUESDAY WHEN A COLD FRONT MOVES THROUGH THE REGION AND STRENGTHENS THE ISENTROPIC LIFT. ACROSS THE NORTHERN ZONES...SURFACE TEMPS MAY GET COLD ENOUGH NEAR THE CORE OF THE UPPER LOW TO SUPPORT A RAIN/SNOW MIX. HOWEVER MODEL GUIDANCE HAS TRENDED THE TRACK OF THE UPPER SYSTEM FARTHER TO THE NORTH. SUCH A TRACK WOULD KEEP THE SNOW POTENTIAL IN OKLAHOMA. COOLER AND DRY WEATHER WILL PREVAIL WEDNESDAY WITH TEMPS NEAR NORMAL. THURSDAY LOOKS WARMER WITH SOUTHERLY WINDS AHEAD OF ANOTHER COLD FRONT THURSDAY NIGHT. TEMPS WILL FALL BELOW NORMAL BEHIND THIS FRONT FOR FRIDAY AND SATURDAY. GFS/ECMWF BOTH HAD PRECIP BEHIND THIS FRONT YESTERDAY BUT THE GFS IS TRENDING DRIER...AND THE 0Z ECMWF IS COMPLETELY DRY. WILL KEEP POPS OUT OF THE FORECAST ON FRIDAY AT THIS TIME. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 63 55 72 41 65 / 20 90 30 5 10 WACO, TX 64 57 74 43 68 / 20 80 50 10 20 PARIS, TX 59 54 68 38 62 / 20 80 60 5 10 DENTON, TX 61 53 71 35 64 / 20 90 30 5 10 MCKINNEY, TX 61 55 70 34 64 / 20 90 40 5 10 DALLAS, TX 63 56 72 43 65 / 20 90 40 5 10 TERRELL, TX 63 57 71 41 65 / 20 80 60 5 10 CORSICANA, TX 64 59 71 45 65 / 20 70 70 10 20 TEMPLE, TX 65 58 74 44 69 / 20 70 60 10 20 MINERAL WELLS, TX 63 50 72 35 67 / 20 90 20 5 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
947 PM EST SUN FEB 10 2013 .SYNOPSIS... A WARM FRONT WILL LIFT NORTHEAST ACROSS THE REGION LATER TONIGHT FOLLOWED BY A TRAILING COLD FRONT THAT WILL SWEEP EAST THROUGH THE AREA MONDAY. ANOTHER STORM SYSTEM LOOKS TO MOVE NORTHEAST ACROSS THE EASTERN CAROLINAS ON WEDNESDAY...POSSIBLY RESULTING IN THE NEXT ROUND OF WINTRY WEATHER FOR MIDWEEK. && .NEAR TERM /THROUGH MONDAY/... AS OF 930 PM EST SUNDAY... WELL...BAND OF SLEET/SOME SNOW AND RAIN MOVED IN CAUSING SOME MINOR TRAVEL ISSUES. THE DUAL POL HAS DONE AN EXCELLENT JOB OF DEPICTING THIS. CURRENTLY...SOME SLEET STILL BEING OBSERVED OVER THE ROANOKE VALLEY. RADAR INDICATES POCKETS OF SLEET AND GIVEN THE DRY AIRMASS...SHOULD SEE THINGS WET BULB ENOUGH TO BRING SLEET TO THE PIEDMONT BUT NO ACCUMULATION HERE GIVEN WARMER TEMPS. OVER THE ALLEGHANY HIGHLANDS OF BATH INTO PORTIONS OF GREENBRIER COULD SEE A FEW TENTHS OF AN INCH OF SNOW/SLEET. THE LATEST RUC HAD THIS NAILED AS FAR AS HAVING A NARROW BAND OF PRECIP AND DRYING IT OUT TO THE WEST. HAVE SINCE FOLLOWED THIS MODEL UNTIL DAWN...BUT LEFT ROOM IN FOR DEVELOPMENT OF LIGHT PRECIP IN THE WEST...BUT ONLY SLIGHT TO LOW CHANCE. MOST AREAS OVERNIGHT WILL BE DRY. WARM FRONT EDGES NWD...BUT IN-SITU WEDGE WILL HOLD AT LEAST UNTIL MID MORNING MONDAY BEFORE THE COLD FRONT ARRIVES. WILL KEEP IT CLOUDY ALL NIGHT. RUC DOES SHOW SOME HIGHER OMEGA RETURNING OVER THE SOUTHERN CWA OVERNIGHT SO KEPT POPS HIGHER HERE. SO IN SUMMARY CUT POPS BACK FROM EARLIER FORECAST. TEMPS COOL SOME WITH PRECIP BUT THERE IS MORE OF AN INCREASE IN THE DEWPOINTS. THINK TEMPS STAY STEADY IN THE WEDGE OR SLOWLY FALL WHILE STEADY OR SLOWLY RISING TEMPS OCCUR OVER THE FAR SW OUTSIDE THE WEDGE BARRING ANY PRECIP. THE WINDS WILL BE STRONGEST BETWEEN THIS AFD AND ABOUT 08Z...WHEN SFC WINDS TURN MORE SSW. COULD BE A FEW GUST ON THE HIGHER RIDGES LIKE MT ROGERS OVER 50 KNOTS...BUT ISOLATED NATURE AND WILL NOT UPGRADE TO HIGH WIND WARNING. PREVIOUS VALID DISCUSSION... A COLD FRONT WILL SWEEP EAST MONDAY. MOST OF THE RAIN WILL END BY MID MORNING MONDAY. IT SHOULD BE WINDY MONDAY WITH DEEP MIXING TO JUST ABOVE H8 AND A WESTERLY DOWNSLOPING FLOW. WIND SPEEDS WILL BE NEAR ADVISORY CRITERIA LEVELS WITH WIND GUSTS ACROSS NORTHWEST NORTH CAROLINA AND INTO THE NEW RIVER VALLEY. HIGHS MONDAY WILL BE MILD WITH READINGS FROM THE LOWER 50S IN THE NORTHWEST TO THE MID 60S IN THE SOUTHEAST. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 345 PM EST SUNDAY... MONDAY NIGHT THROUGH WEDNESDAY NIGHT... MOISTURE BELOW 850 MB IN SOUTHEAST WEST VIRGINIA ALTHOUGH MODELS NOT PRINTING OUT ANY PRECIPITATION. WINDS REMAIN GUSTY UNTIL TUESDAY MORNING. WINDS AND CLOUDS DIMINISH TUESDAY AFTERNOON AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA. HAVE A LIMITED AMOUNT OF SNOW SHOWERS IN WESTERN GREENBRIER COUNTY...BUT CLOUDS WILL HOLD IN LONGER THROUGH THE MORNING IN THE FAVORED UPSLOPE AREAS. NEXT SYSTEM REMAINS COMPLEX. STILL MODEL DIFFERENCES IN TIMING AND EVEN MORE SO IN TEMPERATURE PROFILE. EXPECT BULK OF THE PRECIPITATION BETWEEN 12Z/7AM WEDNESDAY AND 06Z/1AM THURSDAY. TYPE AND AMOUNT OF PRECIPITATION WILL BE A CHALLENGE. NAM BUFKIT WAS SHOWING COLDER TEMPERATURE PROFILES THEN GFS BUFKIT. BEST LOOKING PART OF THE STORM AT THIS POINT IS THE ISENTROPIC LIFT AND UPSLOPE. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 230 PM EST SUNDAY... FROM THURSDAY THROUGH SUNDAY...A LONGWAVE TROUGH IS PROGGED TO BE OVER THE JAMES BAY REGION OF CANADA AND SOUTH INTO THE EASTERN U.S. THAT IS ONE ELEMENT OF THIS PORTION OF THE FORECAST THAT HAS MODERATELY HIGH CONFIDENCE. ANOTHER ELEMENT WITH MODEATELY HIGH CONFIDENCE IS THE TEMPERATURE FORECAST...AT LEAST THE TREND. PROGRESSIVELY COLDER AIR WILL BE ENTERING THE REGION ON GUSTY NORTHWEST WINDS...ESPECIALLY BY THE START OF NEXT WEEKEND. THERE IS LOW CONFIDENCE CONCERNING THE SPEED AND TRACK OF INDIVIDUAL SHORTWAVE TROUGHS WITHIN THE LARGER LONGWAVE TROUGH PATTERN. GUIDANCE COMPARED TO YESTERDAY...AND COMPARED TO EACH OTHER WITH THE LATEST 12Z...7AM...MODELS...OFFER DIFFERENT SOLUTIONS AND EACH WOULD IMPACT THE WEATHER ACROSS OUR REGION IN VARIOUS WAYS. GOING TO LEAN TOWARDS A DRIER...BUT COMPARABLE...SOLUTIION TO THAT OFFERED FOR THIS TIME PERIOD BY HPC. GIVEN THIS...OUR FORECAST WILL REFLECT ONE THAT WILL HAVE PROGRESSIVELY COLDER TEMPERATURES. HIGHS ON THURSDAY WILL BE ROUGHLY 10 TO 15 DEGREE WARMER THAN THOSE EXPECTED ON SUNDAY. LIKEWISE...LOWS ON THURSDAY NIGHT WILL BE ROUGHLY 10 DEGREES MILDER THAN THOSE EXPECTED SATURDAY NIGHT. WE WILL HAVE UPSLOPE RAN/SNOW SHOWERS FORECAST IN SOUTHEAST WEST VIRGINIA AND NEIGHBORING PORTIONS OF SOUTHWEST VIRGINIA THURSDAY NIGHT AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH OHIO VALLEY. BETTER COVERAGE OF PRECIPITATION IS FORECAST SATURDAY AND SATURDAY NIGHT AHEAD OF..AND DURING THE PASSAGE OF A SLIGHTLY MORE ROBUST SHORTWAVE TROUGH THAT WILL HAVE ITS ORIGINS FROM THE CENTRAL PLAINS...AND GET AMPLYFIED AS IT INTERACTS WITH THE EASTERN LONGWAVE TROUGH. BEHIND THIS SYSTEM...UPSLOPE SNOW SHOWERS ARE EXPECTED OVER SOUTHEAST WEST VIRGINIA DURING THE DAY SUNDAY. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... AS OF 645 PM EST SUNDAY... OVERALL...NOT A GOOD NIGHT FOR FLYING MAINLY DUE TO STRONG WIND SHEAR AHEAD OF THE STORM SYSTEM OVER THE MIDWEST SOUTH INTO THE GULF COAST STATES. SFC WINDS WILL BE STAYING LIMITED AT ALL SITES BUT BLF EARLY SO AS WINDS ABOVE THE SFC IN THE 1-2KFT LEVEL INCREASE TO 30-45 KNOTS...WIND SHEAR WILL BE AN ISSUE. AT BLF...THE TYPCIAL SOUTH-SOUTHEAST SFC SETUP WITH WINDS WILL CAUSE THEM TO GUST OVER 30 KTS INTO EARLY MONDAY MORNING...BEFORE THE SHIFT TO A MORE SOUTHWEST DIRECTION TAKES PLACE. AS FAR AS SENSIBLE WEATHER...RAIN AND MAYBE SOME SLEET WILL IMPACT BCB/BLF EARLY SHIFTING EAST INTO ROA/LWB. AIRMASS IS PRETTY DRY OVER THE REGION AND OVERALL EXPECT VFR CIGS WITH OCCASIONAL MVFR VSBYS IN A HEAVIER BAND OF RAIN. WILL HAVE TO WATCH THE RADAR AS ONE MODEL DEPICTS THIS AREA OF RAIN FALLING APART. FOR NOW I AM LEANING TOWARD THE WETTER SOLUTION AND STARTING TO BRING CIGS/VSBYS DOWN TO MVFR/IFR BY MIDNIGHT IN THE WEST AND SHORTLY THEREAFTER EAST. THE LOW LVL WIND SHEAR STARTS TO GO AWAY BY MID MORNING MONDAY AS THE FRONT MOVES ACROSS AND MIXING TAKES PLACE. THE RAIN SHOULD ALSO START TO EXIT LEAVING BEHIND LOWER CIGS IN ITS WAKE WITH UPSLOPE SHOWERS OVER SE WV. THE MIXING SHOULD BRING ABOUT SCATTERING OF LOWER CIGS EAST OF THE WV MTNS BY MIDDAY...WITH GUSTY WEST-NW WINDS AT 20 TO 35 KNOTS POSSIBLE. WILL HAVE BLF CLEARING OUT AS WELL AROUND MIDDAY...GIVEN FAST EXIT OF LOW LVL MOISTURE. EXPECT VFR TO THEN LINGER INTO MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE SPILLING IN FROM THE WEST BEFORE WEAKENING TUESDAY EVENING. ANOTHER AREA OF LOW PRESSURE IS THEN EXPECTED TO FORM ON THE RESIDUAL FRONT TO THE SOUTH BY MIDWEEK WITH PERHAPS ANOTHER ROUND OF PRECIP AND LOWER CIGS ON WEDNESDAY. VFR SHOULD AGAIN RETURN TO ALL SITES ON THURSDAY AS WEAK HIGH PRESSURE BUILDS IN BEHIND THE EXITING AREA OF LOW PRESSURE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY UNTIL 6 AM EST MONDAY FOR VAZ007-009-010-015. NC...WIND ADVISORY UNTIL 6 AM EST MONDAY FOR NCZ001-018. WV...WIND ADVISORY UNTIL 6 AM EST MONDAY FOR WVZ042. && $$ SYNOPSIS...JH/KK NEAR TERM...KK/WP SHORT TERM...AMS/WP LONG TERM...DS AVIATION...JH/KK/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
735 PM EST SUN FEB 10 2013 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE REGION LATER TONIGHT FOLLOWED BY A TRAILING COLD FRONT THAT WILL SWEEP EAST AND BRING A BAND OF RAINFALL OVERNIGHT INTO EARLY MONDAY. ANOTHER STORM SYSTEM LOOKS TO MOVE NORTHEAST ACROSS THE EASTERN CAROLINAS ON WEDNESDAY...POSSIBLY RESULTING IN THE NEXT ROUND OF WINTRY WEATHER FOR MIDWEEK. && .NEAR TERM /THROUGH MONDAY/... AS OF 710 PM EST SUNDAY... OBSERVATIONS FROM THE NC MTNS VIA SOCIAL MEDIA INDICATING SLEET. DUAL-POL RADAR AND REFLECTIVITIES SHOW THIS AS WELL WITH HIGHER REFLECTIVITY NOW MOVING INTO THE MTN EMPIRE OF SW VA. MODEL SOUNDING SUGGES THE POTENTIAL FOR SLEET INTO THE NEW RIVER VALLEY AND NC FOOTHILLS THROUGH ABOUTH 10 PM...BUT OVERALL WILL NOT SEE ANY WINTRY PROBLEMS. THE 21Z RUC IS HANDLING THE EASTWARD EXPANSION A LITTLE BETTER IN PRECIP THAN OTHER MODELS...BUT OVERALL STARTS TO DRY IT UP BY MIDNIGHT. WHILE THIS IS POSSIBLE WILL WAIT FOR ANOTEHR HOUR OR TWO FOR TRENDS...BUT OVERALL NOT EXPECTING AS MUCH QPF AS EARLIER WITH UP TO A QUARTER INCH OR SO. AIRMASS IS VERY DRY AND WILL TAKE A WHILE TO SATURATE WITH THE DEEPEST MOISTURE AND CONVECTION OVER THE GULF COAST STATES ACTING TO INHIBIT MOISTURE TRANSPORT INTO OUR AREA. PREVIOUS VALID DISCUSSION... HIGH PRESSURE WILL MOVE EAST INTO THE ATLANTIC OCEAN TONIGHT. A WARM FRONT WILL LIFT NORTHEAST ACROSS OUR REGION FOLLOWED BY A TRAILING COLD FRONT THAT WILL SWEEP EAST OVERNIGHT INTO MONDAY. STRONG WARM ADVECTION ALONG WITH A QUICK JUMP IN DEWPOINTS SHOULD ALLOW FOR SEVERAL HOURS OF LIGHT/MODERATE RAINFALL WITH BEST COVERAGE BLUE RIDGE WEST BEFORE MIDNIGHT...AND OUT EAST DURING THE EARLY MORNING HOURS. NO FLOODING ANTICIPATED TONIGHT WITH THE HEAVIER RAINFALL TO REMAIN JUST SOUTH PER WEAK SHORTWAVE CROSSING THE CAROLINAS...AND ACROSS THE FAR NORTH CLOSER TO THE OVERALL WEAK DYNAMICS. THERE IS A SMALL WINDOW OF A COUPLE OF HOURS WHERE TEMPERATURES COULD DROP ENOUGH AT THE ONSET OF RAIN IN THE GREENBRIER VALLEY/HIGHLANDS FOR SOME BRIEF FREEZING RAIN. SREF ONLY SHOWING AROUND 10 PERCENT CHANCE OF FREEZING RAIN IN THE NORTHWEST. WITH ONLY SPOTTY COVERAGE AT BEST AND TEMPERATURES RAISING OVERNIGHT...ELECTED KEEP PTYPE AS RAIN. DEEPER WARM AIR ALOFT WORKS TO THE SURFACE BEHIND THE WARM FRONT LIFTING NORTH AND AHEAD OF THE COLD FRONT THAT WILL BE NEAR THE WESTERN SLOPES BY DAYBREAK. USED NON-DIURNAL TEMPERATURE CURVE FOR LOW TEMPERATURES WITH VALUES GENERALLY FROM THE MID 30S IN THE NORTHWEST TO THE LOWER 40S IN THE SOUTHEAST. ANOTHER CONCERN WITH SOUTH/SOUTHEAST WINDS ACROSS PARTS OF THE WESTERN MOUNTAINS TONIGHT AS MODELS DEPICT 50-55 KTS WITH DECENT MIXING EARLY AHEAD OF THE BAND OF RAIN. WIND ADVISORIES IN THE WEST WILL CONTINUE UNTIL 6 AM MONDAY. MOST OF THE RAIN WILL END BY MID MORNING MONDAY. IT SHOULD BE WINDY MONDAY WITH DEEP MIXING TO JUST ABOVE H8 AND A WESTERLY DOWNSLOPING FLOW. WIND SPEEDS WILL BE NEAR ADVISORY CRITERIA LEVELS WITH WIND GUSTS ACROSS NORTHWEST NORTH CAROLINA AND INTO THE NEW RIVER VALLEY. HIGHS MONDAY WILL BE MILD WITH READINGS FROM THE LOWER 50S IN THE NORTHWEST TO THE MID 60S IN THE SOUTHEAST. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 345 PM EST SUNDAY... MONDAY NIGHT THROUGH WEDNESDAY NIGHT... MOISTURE BELOW 850 MB IN SOUTHEAST WEST VIRGINIA ALTHOUGH MODELS NOT PRINTING OUT ANY PRECIPITATION. WINDS REMAIN GUSTY UNTIL TUESDAY MORNING. WINDS AND CLOUDS DIMINISH TUESDAY AFTERNOON AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA. HAVE A LIMITED AMOUNT OF SNOW SHOWERS IN WESTERN GREENBRIER COUNTY...BUT CLOUDS WILL HOLD IN LONGER THROUGH THE MORNING IN THE FAVORED UPSLOPE AREAS. NEXT SYSTEM REMAINS COMPLEX. STILL MODEL DIFFERENCES IN TIMING AND EVEN MORE SO IN TEMPERATURE PROFILE. EXPECT BULK OF THE PRECIPITATION BETWEEN 12Z/7AM WEDNESDAY AND 06Z/1AM THURSDAY. TYPE AND AMOUNT OF PRECIPITATION WILL BE A CHALLENGE. NAM BUFKIT WAS SHOWING COLDER TEMPERATURE PROFILES THEN GFS BUFKIT. BEST LOOKING PART OF THE STORM AT THIS POINT IS THE ISENTROPIC LIFT AND UPSLOPE. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 230 PM EST SUNDAY... FROM THURSDAY THROUGH SUNDAY...A LONGWAVE TROUGH IS PROGGED TO BE OVER THE JAMES BAY REGION OF CANADA AND SOUTH INTO THE EASTERN U.S. THAT IS ONE ELEMENT OF THIS PORTION OF THE FORECAST THAT HAS MODERATELY HIGH CONFIDENCE. ANOTHER ELEMENT WITH MODEATELY HIGH CONFIDENCE IS THE TEMPERATURE FORECAST...AT LEAST THE TREND. PROGRESSIVELY COLDER AIR WILL BE ENTERING THE REGION ON GUSTY NORTHWEST WINDS...ESPECIALLY BY THE START OF NEXT WEEKEND. THERE IS LOW CONFIDENCE CONCERNING THE SPEED AND TRACK OF INDIVIDUAL SHORTWAVE TROUGHS WITHIN THE LARGER LONGWAVE TROUGH PATTERN. GUIDANCE COMPARED TO YESTERDAY...AND COMPARED TO EACH OTHER WITH THE LATEST 12Z...7AM...MODELS...OFFER DIFFERENT SOLUTIONS AND EACH WOULD IMPACT THE WEATHER ACROSS OUR REGION IN VARIOUS WAYS. GOING TO LEAN TOWARDS A DRIER...BUT COMPARABLE...SOLUTIION TO THAT OFFERED FOR THIS TIME PERIOD BY HPC. GIVEN THIS...OUR FORECAST WILL REFLECT ONE THAT WILL HAVE PROGRESSIVELY COLDER TEMPERATURES. HIGHS ON THURSDAY WILL BE ROUGHLY 10 TO 15 DEGREE WARMER THAN THOSE EXPECTED ON SUNDAY. LIKEWISE...LOWS ON THURSDAY NIGHT WILL BE ROUGHLY 10 DEGREES MILDER THAN THOSE EXPECTED SATURDAY NIGHT. WE WILL HAVE UPSLOPE RAN/SNOW SHOWERS FORECAST IN SOUTHEAST WEST VIRGINIA AND NEIGHBORING PORTIONS OF SOUTHWEST VIRGINIA THURSDAY NIGHT AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH OHIO VALLEY. BETTER COVERAGE OF PRECIPITATION IS FORECAST SATURDAY AND SATURDAY NIGHT AHEAD OF..AND DURING THE PASSAGE OF A SLIGHTLY MORE ROBUST SHORTWAVE TROUGH THAT WILL HAVE ITS ORIGINS FROM THE CENTRAL PLAINS...AND GET AMPLYFIED AS IT INTERACTS WITH THE EASTERN LONGWAVE TROUGH. BEHIND THIS SYSTEM...UPSLOPE SNOW SHOWERS ARE EXPECTED OVER SOUTHEAST WEST VIRGINIA DURING THE DAY SUNDAY. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 645 PM EST SUNDAY... OVERALL...NOT A GOOD NIGHT FOR FLYING MAINLY DUE TO STRONG WIND SHEAR AHEAD OF THE STORM SYSTEM OVER THE MIDWEST SOUTH INTO THE GULF COAST STATES. SFC WINDS WILL BE STAYING LIMITED AT ALL SITES BUT BLF EARLY SO AS WINDS ABOVE THE SFC IN THE 1-2KFT LEVEL INCREASE TO 30-45 KNOTS...WIND SHEAR WILL BE AN ISSUE. AT BLF...THE TYPCIAL SOUTH-SOUTHEAST SFC SETUP WITH WINDS WILL CAUSE THEM TO GUST OVER 30 KTS INTO EARLY MONDAY MORNING...BEFORE THE SHIFT TO A MORE SOUTHWEST DIRECTION TAKES PLACE. AS FAR AS SENSIBLE WEATHER...RAIN AND MAYBE SOME SLEET WILL IMPACT BCB/BLF EARLY SHIFTING EAST INTO ROA/LWB. AIRMASS IS PRETTY DRY OVER THE REGION AND OVERALL EXPECT VFR CIGS WITH OCCASIONAL MVFR VSBYS IN A HEAVIER BAND OF RAIN. WILL HAVE TO WATCH THE RADAR AS ONE MODEL DEPICTS THIS AREA OF RAIN FALLING APART. FOR NOW I AM LEANING TOWARD THE WETTER SOLUTION AND STARTING TO BRING CIGS/VSBYS DOWN TO MVFR/IFR BY MIDNIGHT IN THE WEST AND SHORTLY THEREAFTER EAST. THE LOW LVL WIND SHEAR STARTS TO GO AWAY BY MID MORNING MONDAY AS THE FRONT MOVES ACROSS AND MIXING TAKES PLACE. THE RAIN SHOULD ALSO START TO EXIT LEAVING BEHIND LOWER CIGS IN ITS WAKE WITH UPSLOPE SHOWERS OVER SE WV. THE MIXING SHOULD BRING ABOUT SCATTERING OF LOWER CIGS EAST OF THE WV MTNS BY MIDDAY...WITH GUSTY WEST-NW WINDS AT 20 TO 35 KNOTS POSSIBLE. WILL HAVE BLF CLEARING OUT AS WELL AROUND MIDDAY...GIVEN FAST EXIT OF LOW LVL MOISTURE. EXPECT VFR TO THEN LINGER INTO MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE SPILLING IN FROM THE WEST BEFORE WEAKENING TUESDAY EVENING. ANOTHER AREA OF LOW PRESSURE IS THEN EXPECTED TO FORM ON THE RESIDUAL FRONT TO THE SOUTH BY MIDWEEK WITH PERHAPS ANOTHER ROUND OF PRECIP AND LOWER CIGS ON WEDNESDAY. VFR SHOULD AGAIN RETURN TO ALL SITES ON THURSDAY AS WEAK HIGH PRESSURE BUILDS IN BEHIND THE EXITING AREA OF LOW PRESSURE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY UNTIL 6 AM EST MONDAY FOR VAZ007-009-010-015. NC...WIND ADVISORY UNTIL 6 AM EST MONDAY FOR NCZ001-018. WV...WIND ADVISORY UNTIL 6 AM EST MONDAY FOR WVZ042. && $$ SYNOPSIS...JH/KK NEAR TERM...KK SHORT TERM...AMS/WP LONG TERM...DS AVIATION...JH/KK/WP
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1017 AM PST Sat Feb 9 2013 .SYNOPSIS... Dry and stable weather is on tap for the weekend. Some light snow will be possible over the Idaho Panhandle mountains today and tonight, but the remainder of the Inland Northwest will have a good chance of experiencing some sunshine. The next storm system is expected to arrive on Tuesday bringing an increased potential for rain and mountain snow. && .DISCUSSION... Update: a frontal wave continues to track into the Canadian Prairies this morning, with the supporting mid-level shortwave diving through Alberta and southeast British Columbia. WV/IR imagery showed the center of latter feature working through Edmonton, Alberta. A jet streak and mid-level diffluence on its west-southwest side was nosing into the Inland Northwest, leading to a modest higher level cloud deck. Meanwhile low level moisture and an inversion topped between 3500-4000 feet MSL is holding low clouds and fog in place across northeast Washington and a large portion of the Panhandle. Satellite extrapolation of the higher cloud deck and model guidance supports this feature dissipating from the north through the mid to later afternoon. As for the low clouds and fog, the 12Z KOTX sounding well. The RUC13 is closest. Overall this is expected to be slow. I increased the stratus and continued the fog through the afternoon, though allow it to be patchier and indicated shrinking coverage. Locally dense fog was noted on area webcams and by spotter reports toward the West Plains into Lincoln county. Will continue to handle with NOWCASTs. As for precipitation, the threat of light snow showers will continue to spread into the Panhandle and southeast zones, including the Blues through Camas Prairie, with the previously described shortwave disturbance coming in. The ongoing forecast in this respect looks reasonable. Temperatures are also on track. /J. Cote` && .AVIATION... 18Z: Areas of IFR low clouds will impact portions of KGEG-KCOE and in the vcnty of KPUW, with patchy fog, before some MVFR/VFR conditions briefly develop. Low level inversions, stronger than most guidance, will help to keep these conditions in place. Confidence on how fully things break up and durations are small, but a brief period is projected, before conditions degrade after dark again. The KLWS is expected to be mainly VFR, but brief MVFR conditions are possible. A mid-level shortwave passing by will bring a threat of light snow showers to the central Panhandle through the Camas Prairie, a few of which may slip near KCOE and possibly KPUW/KLWS this afternoon and evening. Western TAFs are expected to be mainly dry and VFR. /J. Cote` && .PRELIMINARY POINT TEMPS/POPS... Spokane 35 21 36 23 35 29 / 0 0 0 0 10 20 Coeur d`Alene 35 21 36 23 35 30 / 10 0 0 0 10 20 Pullman 35 24 38 25 39 31 / 10 10 0 0 0 20 Lewiston 42 29 43 29 43 35 / 10 10 0 0 0 10 Colville 41 24 40 22 38 30 / 0 0 0 0 10 20 Sandpoint 36 24 36 26 35 30 / 10 10 0 0 10 30 Kellogg 35 24 37 27 39 30 / 20 20 10 10 10 30 Moses Lake 43 25 42 24 41 29 / 0 0 0 0 0 0 Wenatchee 43 26 42 25 40 29 / 0 0 0 0 0 0 Omak 36 21 37 20 35 24 / 0 0 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
829 PM CST SUN FEB 10 2013 .SHORT TERM...TONIGHT 829 PM CST SUN FEB 10 2013 WIND ADVISORY TO BE ISSUED SHORTLY...SEE DETAILS BELOW. THE CORE OF A LOW PRESSURE SYSTEM IS CURRENTLY JUST TO THE WEST OF THE FORECAST AREA ALONG THE I-35 CORRIDOR IN SOUTH CENTRAL MINNESOTA. EAST OF THIS LOW...A WARM FRONT EXTENDS TO THE WEST INTO WESTERN WISCONSIN WITH WIDESPREAD RAIN AND DRIZZLE OCCURRING ALONG AND TO THE SOUTH OF IT. SOME FOG STILL REMAINS ALONG AND NORTH OF THIS FRONT...BUT VISIBILITY HAS NOT BEEN BELOW A MILE IN THIS REGION...SO WILL BE DROPPING THE FOG FROM THE FORECAST. BASED ON RADAR AND THE LATEST OBSERVATIONS...IT APPEARS THAT THE BACK EDGE OF THE RAIN/DRIZZLE IS RAPIDLY MOVING TO THE NORTHEAST ACROSS NORTHEAST IOWA. EXPECT THAT AS THIS BACK EDGE MOVES THROUGH THAT THERE WILL BE A PERIOD OF DRY CONDITIONS THIS EVENING AND OVERNIGHT. FURTHER TO THE WEST...MAINLY ALONG AND SOUTH OF THE SURFACE LOW...PRECIPITATION HAS CHANGED OVER TO SNOW ALONG THE I-35 CORRIDOR WHERE 11.00Z RAP/LAPS SOUNDINGS INDICATE THAT THE THERMAL PROFILE HAS COOLED TO ALL BEING BELOW FREEZING. DODGE COUNTY AND PORTIONS OF SOUTHEAST MINNESOTA MAY GET CLIPPED BY SOME OF THIS SNOW...BUT IT APPEARS TO MAINLY BE PROPAGATING TO THE NORTHEAST AND SHOULD NOT DROP MUCH ACROSS THIS REGION. AS THE LOW MOVES OFF TO THE NORTHEAST...THE COLD FRONT THAT CURRENTLY EXTENDS TO THE SOUTHEAST OF IT INTO WESTERN IOWA WILL SWING THROUGH THE REGION AROUND AND SHORTLY AFTER MIDNIGHT. SNOW SHOWERS WILL MOVE IN AFTER THE FRONT PASSES THOUGH THEY WILL NOT BE VERY INTENSE. VISIBILITIES HAVE MAINLY BEEN IN THE 1-3SM RANGE AND THAT IS EXPECTED TO BE THE LOW END OF WHAT WE WILL SEE AS IT MOVES INTO THE REGION OVERNIGHT INTO TOMORROW. THE TIGHTENING SURFACE PRESSURE GRADIENT WILL ALSO TRACK TO THE NORTHEAST WITH THE LOW MOVING IN THAT DIRECTION. THE CORE OF THESE STRONG WINDS WILL EXTEND ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA AND SOUTHWEST WISCONSIN...PARTICULARLY IN THE HIGHER ELEVATIONS. 11.00Z AND PREVIOUS RAP BUFKIT SOUNDINGS SHOW THAT WIND GUSTS SHOULD BE AROUND 45 MPH AT TIMES...PARTICULARLY TOMORROW MORNING AFTER SUNRISE. WILL BE ISSUING A WIND ADVISORY STARTING AT MIDNIGHT AND RUNNING IT INTO 3PM TOMORROW AFTERNOON WHEN IT APPEARS THAT THE WINDS WILL WEAKEN ALONG WITH THE PRESSURE GRADIENT. THE LOBE OF STRONGEST WINDS WILL START OUT IN THE SOUTH AND WORK THEIR WAY NORTHWARD AFTER MIDNIGHT...SO SOME LOCATIONS IN THE ADVISORY MAY BE A LITTLE DELAYED IN GETTING THE STRONGEST WINDS COMPARED TO THAT AREA. .LONG TERM...WEDNESDAY THROUGH SUNDAY 256 PM CST SUN FEB 10 2013 NORTHWEST FLOW ALOFT WILL SET UP OVER THE UPPER MIDWEST IN THE WAKE OF THE CURRENT STORM SYSTEM. THIS WILL ALLOW A SYSTEM TO DROP INTO THE REGION FOR THE MIDDLE OR END OF THE WEEK. THE MODELS SHOW VERY LITTLE CONSISTENCY ON THE TIMING OF THIS FEATURE. THE 10.12Z GFS IS THE FASTEST BRINGING IN WEDNESDAY AFTERNOON WHILE THE 10.12Z GEM IS THE SLOWEST AND STRONGEST AND DOES NOT BRING IT IN UNTIL THURSDAY NIGHT. UNTIL THESE TIMING DIFFERENCES ARE WORKED OUT...WILL NEED TO CARRY A MENTION OF PRECIPITATION FROM WEDNESDAY NIGHT THROUGH FRIDAY WITH THE BEST CHANCES CENTERED ON WEDNESDAY NIGHT AND THURSDAY. THE SURFACE LOW MAY PASS BY JUST TO THE NORTH OF THE AREA THURSDAY BRINGING ENOUGH WARM AIR FOR A MIX OF RAIN AND SNOW ACROSS THE SOUTH WITH LIGHT SNOW EXPECTED ELSEWHERE. && .AVIATION...TONIGHT AND MONDAY 607 PM CST SUN FEB 10 2013 LIFR TO MVFR CONDITIONS WILL OCCUR THROUGH TOMORROW AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE REGION. THE CORE OF THIS LOW IS CURRENTLY IN SOUTH CENTRAL MINNESOTA WITH A WARM FRONT EXTENDING EAST FROM THIS FEATURE. A BAND OF RAIN AND DENSE FOG WITH VISIBILITY AT A QUARTER MILE OR LESS HAS DEVELOPED ALONG AND TO THE NORTH OF THIS FRONT AND HAS BEEN IN PLACE AT RST FOR THE PAST FEW HOURS. SOUTH OF THE FRONT...CONDITIONS IMPROVE TO MVFR AND CURRENT EXTRAPOLATION BRINGS THE BETTER VISIBILITY AND CEILINGS INTO RST RIGHT AROUND NOW AND LSE AROUND 2Z. VISIBILITY HAS BEEN UP AT 10SM AT LSE...BUT CEILINGS HAVE BEEN IFR AT 900FT. EXPECT THAT THERE SHOULD BE A DROP IN THESE CONDITIONS BEFORE THE IMPROVEMENT MOVES IN AROUND 2Z. WINDS WILL SHIFT AROUND TO THE SOUTHWEST AS WELL AND MAY BECOME GUSTY AT RST. THE COLD FRONT WITH THIS SYSTEM WILL THEN MOVE THROUGH RST AROUND 6Z AND LSE AROUND 8/9Z TONIGHT AND SHOULD BRING A LOWER CLOUD DECK AND SNOW SHOWERS IN WITH IT. NOT VERY CONFIDENT IN HOW INTENSE THE SNOW WILL BE AT THIS POINT...BUT PLAYED IT AS GRADUALLY IMPROVING INTO MONDAY. WINDS WILL BE THE MAIN ISSUE WITH GUSTS CRANKING UP TO AROUND 30-35KTS OUT OF THE NORTHWEST BY TOMORROW MORNING. && .ARX WATCHES/WARNINGS/ADVISORIES... 829 PM CST SUN FEB 10 2013 WI...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR WIZ032>034-041>044-053>055-061. MN...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR MNZ079-086>088-094>096. IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR IAZ008>011-018-019-029-030. && $$ SHORT TERM...HALBACH LONG TERM...04 AVIATION...HALBACH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1012 AM CST SAT FEB 9 2013 .UPDATE...VISIBILITIES CONTINUE TO IMPROVE THIS MORNING...SO ALLOWED THE FREEZING FOG ADVISORY TO EXPIRE. MAIN ISSUE FOR THE REMAINDER OF THE DAY IS HOW LONG THIS LOW LEVEL CLOUD DECK WILL STICK AROUND. LATEST RAP AND NAM SOUNDINGS INDICATED THESE CLOUDS MAY NOT GO AWAY FOR A WHILE...THE NAM NOT SHOWING CLEARING SKIES AT MADISON UNTIL TUESDAY AFTERNOON. WILL CONSIDER INCREASING CLOUDS...AND CONSEQUENTLY LOWERING HIGH TEMPS A TAD IF THIS CLOUD DECK SHOWS NO SIGNS OF ERODING. && .AVIATION/18Z TAFS/...VISIBILITIES CONTINUE TO IMPROVE THIS MORNING...WITH THE REMAINING CONCERN TODAY BEING HOW LONG THIS LOW LEVEL CLOUD DECK WILL STICK AROUND. LATEST RAP AND NAM SOUNDINGS INDICATED THESE CLOUDS MAY HANG AROUND THROUGH THE REMAINDER OF THE DAY. WILL ASSESS NEW MODEL DATA AND MONITOR OBS...CONSIDERING EXTENDING LOW CIGS IN THE TAFS FOR A WHILE LONGER. PRECIPITATION WILL MOVE IN FROM THE SOUTHWEST VERY LATE TONIGHT INTO SUNDAY MORNING. GOOD CHANCE FOR A PERIOD OF FREEZING RAIN...ESPECIALLY ALONG AND SOUTHWEST OF A WISCONSIN DELLS TO MILWAUKEE LINE WHERE TEMPERATURES WILL BE COLDER WHEN THE RAIN INITIALLY ARRIVES. MAY CAUSE PROBLEMS FOR A SHORT WHILE...THOUGH TEMPERATURES WILL WARM THROUGH THE DAY...WITH ALL RAIN EXPECTED BY LATE MORNING OR EARLY AFTERNOON. LOWER CIGS AND VSBYS LIKELY BY SUNDAY AFTERNOON AS PRECIPITATION AND HIGHER DEWPOINTS MOVE IN OVER SNOWPACK. && .PREV DISCUSSION... /ISSUED 346 AM CST SAT FEB 9 2013/ SHORT TERM... TODAY AND TONIGHT-FORECAST CONFIDENCE MEDIUM TO HIGH SURFACE HIGH PRESSURE OVER THE GREAT LAKES WILL MOVE OFF TO THE EAST AS SOUTH WINDS INCREASE TODAY AND TONIGHT. AREAS OF STRATUS AND PATCHY FOG WILL BE A CONCERN ESPECIALLY THIS MORNING. ALSO LAKE CLOUDS MAY PUSH IN TO THE EAST AS LOW LEVEL WINDS BECOME SOUTHEAST. MID/UPPER LEVEL RIDGE BRIEFLY BUILDS OVER WISCONSIN TODAY. THEN THE STRONG SHORTWAVE OVER THE SOUTHWEST U.S. MOVES ACROSS COLORADO THIS AFTERNOON AND INTO CENTRAL NEBRASKA BY SUNRISE SUNDAY. 250 MB DIVERGENCE INCREASES LATE TONIGHT ESPECIALLY OVER SOUTH CENTRAL WISCONSIN. 850/700 MB WARM AIR ADVECTION BEGINS TODAY AND TONIGHT...BUT 850 MB TEMPERATES COOL A LITTLE TOWARD SUNRISE DUE TO EVAPORATIVE COOLING WITH THE DEVELOPING MID LEVEL SATURATION AND UPWARD MOTION. 850/700 MB MOISTURE CONVERGENCE INCREASES LATE TONIGHT. SOME PRECIPITATION MAY REACH THE GROUND TOWARD SUNRISE...MAINLY IN AREAS SOUTH AND WEST OF MADISON. PRECIPITATION TYPE WOULD BE A MIX GIVEN THE WARMING ABOVE ZERO CELSIUS IN THE SOUTHWEST AROUND 1 TO 4 THSD FT. EVAPORATIVE COOLING COULD CAUSE ANY INITIAL PRECIPITATION TO BE BRIEFLY SNOW...BEFORE FREEZING RAIN WOULD QUICKLY BECOME THE MAIN PRECIPITATION TYPE SUNDAY MORNING. ANY PRECIPITATION LATE TONIGHT WOULD BE LIGHT. SUNDAY-FORECAST CONFIDENCE HIGH DEEP LOW STILL SHOWN TO CROSS FROM NEBRASKA INTO NORTH CENTRAL IOWA SUNDAY...AND THEN CLIP SOUTHEAST MINNESOTA ON ITS WAY TO NORTHERN WISCONSIN SUNDAY NIGHT. MODELS PRETTY CONSISTENT ON TIMING OF PRECIPITATION IN WARM ADVECTION REGIME SPREADING NORTH. ONE DIFFERENCE IS THAT THERMAL PROFILES NO LONGER SUPPORT SLEET AT THE ONSET...WITH WARM LAYER DEEPER AND AROUND +3C AND SURFACE COLD LAYER SHALLOWER. NAM IS PRETTY AGGRESSIVE WITH QPF AND BUFKIT SHOWS ABOUT 0.25" OF FREEZING RAIN AT MSN AND MKX. WENT WITH A MORE CONSERVATIVE APPROACHING CLOSER TO GFS AND SREF SOLUTIONS WHICH HAVE LESS THAN 0.10" OF ICE. CONSIDERED A FREEZING RAIN ADVISORY FROM 12-17Z. IN COORDINATION WITH NWS LA CROSSE AND TWIN CITIES WILL HOLD OFF ON ADVISORY UNTIL LATER THIS MORNING SO THAT MPX CAN SHORE UP A COMPLICATED SET OF HEADLINES. IT IS A MARGINAL EVENT AND THIS WOULD BE 3RD PERIOD...SO STILL PLENTY OF TIME TO GET THE WORD OUT. WILL ISSUE AN SPS TO RAMP THINGS UP. OTHERWISE NICE SLUG OF RAIN ON ORDER OF 0.25 TO 0.50" ON TAP WITHIN 50 KNOT 850 LOW LEVEL JET AXIS. DRY SLOT WORKS INTO AREA LATE AFTERNOON AND EVENING WITH RAIN TAPERING TO DRIZZLE. GIVEN SNOW COVER AND MODEST WINDS...AREAS OF FOG IN ORDER BUT NOT SURE ABOUT HOW DENSE GIVEN WEAKER GRADIENT NEAR SURFACE LOW GOES WELL NORTH. AS COLDER AIR WORKS IN AFTER MIDNIGHT...EXPECT DRIZZLE AND LIGHT RAIN TO TURN OVER TO VERY LIGHT SNOW. MONDAY-FORECAST CONFIDENCE HIGH DEEP OCCLUDED LOW BEGINS TO FILL AS IT PULLS AWAY FROM WISCONSIN AND CROSSES NORTHERN LAKE MICHIGAN AND LAKE HURON. CYCLONIC FLOW WITH COLD WEST TO NORTHWEST FLOW AND STEEP LOW LEVEL LAPSE RATES SUGGESTS WINDY CONDITIONS WITH GUSTS OF 30 TO 35 KNOTS. LOOKS MARGINAL FOR WIND ADVISORY BUT GALE CONDITIONS POSSIBLE OVER LAKE MICHIGAN. BUFKIT SHOWING TOUCH OF CAPE IN BOUNDARY LAYER BUT DOES NOT QUITE REACH THE DENDRITE ZONE. VERY LIGHT SNOW IN CYCLONIC WRAP AROUND SEEMS LIKELY...BUT JUST A COUPLE HUNDREDTHS OF QPF SHOWN SO LESS THAN AN INCH OF ANY ACCUMULATION OCCURS. LONG TERM... TUESDAY AND WEDNESDAY-FORECAST CONFIDENCE HIGH DRY AND SEASONABLY COLD NORTHWEST FLOW SITUATION EXPECTED WITH QUIET WEATHER RESULTING. THURSDAY AND FRIDAY-FORECAST CONFIDENCE MEDIUM ALTHOUGH THERE IS A TYPICAL AMOUNT OF DIFFERENCE IN THE GUIDANCE AT DAY 6 AND 7...MODELS HAVE CONVERGENCED A BIT AND ECMWF REMAINS PRETTY CONSISTENT AND BRINGING ANOTHER SNOW EVENT. ECMWF AND GEMNH HAVE A CLIPPER LIKE SYSTEM DIGGING SOUTHEAST ACROSS THE NORTHERN PLAINS AND THEN TURNING THE CORNER AROUND IOWA TO ILLINOIS. LOOKS FAVORABLE FOR ACCUMULATING SNOW BUT GFS IS STILL MUCH WEAKER AND DRIER WITH THIS SYSTEM...FOCUSING MORE ON DEVELOPMENT TOWARD THE WEEKEND ALONG THE EAST COAST. THIS CERTAINLY COULD TURN INTO AN ADVISORY TYPE SNOW EVENT AND BUMPED UP POPS TO CHANCE GIVEN BETTER MODEL AGGREMENT. AVIATION/12Z TAFS/... SURFACE HIGH PRESSURE OVER THE GREAT LAKES WILL MOVE OFF TO THE EAST AS SOUTH WINDS INCREASE TODAY AND TONIGHT. AREAS OF IFR STRATUS AND PATCHY LIFR FOG WILL BE A CONCERN ESPECIALLY THIS MORNING. ALSO MVFR LAKE CLOUDS MAY PUSH IN TO THE EAST AS LOW LEVEL WINDS BECOME SOUTHEAST. AS STRONG LOW PRESSURE EXITS COLORADO AND REACHES THE CENTRAL PLAINS SOME PRECIPITATION MAY REACH THE GROUND TOWARD SUNRISE...MAINLY IN AREAS SOUTH AND WEST OF MADISON. PRECIPITATION TYPE WOULD BE A MIX GIVEN THE WARMING ABOVE ZERO CELSIUS IN THE SOUTHWEST AROUND 1 TO 4 THSD FT. EVAPORATIVE COOLING COULD CAUSE ANY INITIAL PRECIPITATION TO BE BRIEFLY SNOW...BEFORE FREEZING RAIN WOULD QUICKLY BECOME THE MAIN PRECIPITATION TYPE SUNDAY MORNING. ANY PRECIPITATION LATE TONIGHT WOULD BE LIGHT. MARINE... SOUTHEAST WINDS MAY REACH SMALL CRAFT CRITERIA TONIGHT. SMALL CRAFT ADVISORY CONDITIONS WILL BE LIKELY FOR SUNDAY AND MONDAY AS STRONG LOW PRESSURE MOVES FROM THE CENTRAL PLAINS TO FAR NORTHWEST WISCONSIN. SOME GALE WINDS WILL BE POSSIBLE MAINLY SUNDAY EVENING AND MONDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR LMZ643>646. && $$ UPDATE...DDV TODAY/TONIGHT AND AVIATION/MARINE...HENTZ SUNDAY THROUGH FRIDAY...CRAVEN
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
350 AM EST MON FEB 11 2013 .SYNOPSIS... 08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CHAOTIC UPPER LEVEL PATTERN ACROSS THE MID-SECTION OF THE COUNTRY CONSISTING OF 2 CLOSED UPPER LOW FEATURES. THE FIRST IS EJECTING EASTWARD ACROSS THE UPPER MIDWEST AND GREAT LAKES WHILE THE SECOND IS FURTHER UPSTREAM NEAR THE 4-CORNERS REGION. IN RESPONSE TO THE HEIGHT FALLS SEEN OVER THE CENTRAL STATES...THE DOWNSTREAM RIDGE AS BEEN AMPLIFIED AND IS NOW QUITE SHARP AS ITS AXIS BEGINS TO EXIT THE EASTERN SEABOARD. THE FL PENINSULA RESIDES AT THE BASE OF THE EAST COAST RIDGE. THE INFLUENCE OF THIS FEATURE ON OUR COLUMN WAS SAMPLED WELL BY THE 11/00Z KTBW SOUNDING WHICH SHOWED A DEFINED SUBSIDENCE INVERSION AROUND 800MB. AT THE SURFACE...STRONG HIGH PRESSURE HAS BEEN PUSHED OFF THE ATLANTIC SEABOARD BY A COLD FRONT MOVING THROUGH THE APPALACHIANS...BUT CONTINUES TO RIDGE TO THE SOUTHWEST ACROSS THE LOCAL AREA AND EASTERN GULF. THIS PRESSURE PATTERN IS ALLOWING FOR A LIGHT EAST TO SOUTHEAST FLOW AND A SLOW INCREASE IN LOW LEVEL MOISTURE. REGIONAL RADARS SHOW PLENTY OF SHOWERS AND STORMS TO OUR NORTHWEST TOWARD THE I-10 CORRIDOR. THIS ACTIVITY WILL NOT BE A THREAT TO OUR ZONES AS SUPPORTING ENERGY QUICKLY EXITS LATER TODAY AND THE FRONT NEVER REACHES THIS FAR SOUTH. && .SHORT TERM (TODAY THROUGH WEDNESDAY)... TODAY/TONIGHT... UPPER RIDGE OVER THE EASTERN SEABOARD WILL QUICKLY BREAK DOWN AS A STRONG UPPER LOW QUICKLY TRANSLATES EASTWARD THROUGH THE GREAT LAKES TOWARD THE NORTHEAST/MID-ATLANTIC. LUCKILY FOR OUR FORECAST...SOME RESIDUAL RIDGING WILL HOLD ON DOWN TOWARD THE FLORIDA PENINSULA... AND THIS PATTERN OVER-TOP AN EAST-WEST ORIENTED SURFACE RIDGE WILL KEEP OUR LOCAL WEATHER GENERALLY FAIR...DRY...AND WARM. AS MENTIONED ABOVE...ANY SHOWER ACTIVITY SHOULD STAY TO OUR NORTH TODAY AND WILL KEEP MENTION OUT OF THE FORECAST. EFFICIENT DIURNAL MIXING AND A LOW LEVEL COLUMN FEATURING 850MB TEMPS BETWEEN 12-14C WILL ALLOW FOR A QUICK DIURNAL RISE IN TEMPERATURES INTO THE UPPER 70S AND LOWER 80S. MAY SEE SOME ONSHORE COMPONENT DEVELOP ALONG THE IMMEDIATE COAST DURING THE AFTERNOON WHICH WILL KEEP TEMPS DOWN A FEW DEGREES FROM LOCATIONS FURTHER INLAND...BUT EVEN STILL A DECENT BEACH DAY IS IN STORE. LOW TEMPERATURES TONIGHT WILL BOTTOM OUT ONLY IN THE UPPER 50S TO LOWER 60S FOR MOST SPOTS AND IN THE MIDDLE 60S ALONG THE COAST FROM TAMPA BAY SOUTHWARD. THE INCREASING LOW LEVEL DEWPOINTS WILL BEGIN TO APPROACH A CRITICAL POINT LATER TONIGHT OVER THE COOLER SHELF WATERS...AND CONCERNED FOR THE POTENTIAL DEVELOPING OF SOME ADVECTION SEA-FOG. MANY OF THE HIGHER RESOLUTION GUIDANCE MEMBERS ARE AGGRESSIVE IN THIS SEA-FOG DEVELOPMENT FROM THE MANATEE COUNTY COAST AND NORTHWARD...AND ADDED AREAS OF FOG TO THE GRIDS. TUESDAY/TUESDAY NIGHT... NEXT SHORTWAVE WILL BEGIN TO MOVE EASTWARD FROM THE SOUTHERN PLAINS AND SUPPORT AND ORGANIZING AREA OF LOW PRESSURE NEAR THE LA/MS/AL COAST BY LATE IN THE DAY. A WARM FRONTAL FEATURE WILL EXTEND EASTWARD FROM THIS LOW ALONG THE I-10 CORRIDOR. THIS CONFIGURATION WILL PLACE OUR REGION WITHIN THE WARM SECTOR AND REMOVED FROM ANY DECENT UPGLIDE OVER THE FRONT. WITH THIS IN MIND...MAY SEE A FEW SCATTERED SHOWERS AS FAR SOUTH AS LEVY COUNTY...BUT ANY ORGANIZED CONVECTION WILL BE FURTHER NORTH INTO AL/GA. THE REMAINDER OF THE AREA...WILL BE GENERALLY DRY (OUTSIDE OF AN ISOLATED INSTABILITY SHOWER). IF THE SEA-FOG POTENTIAL DOES COME TO VERIFY...THEN WE WOULD STILL BE DEALING WITH THESE VISIBILITY ISSUES DURING THE MORNING HOURS...WITH DIURNAL MIXING SHRINKING THE MAIN VIS RESTRICTION REGION BACK TO THE MARINE ZONES AND IMMEDIATE NATURE COAST FOR THE SECOND HALF OF THE DAY. THE AREA OF LOW PRESSURE WILL MOVE NORTHEAST ACROSS AL TUESDAY NIGHT WITH A TRAILING COLD FRONT APPROACHING FROM THE WEST. TIMING OF THE FRONT AND SWATH OF LARGE SCALE LIFT/QG FORCING LOOKS TO KEEP THE BEST SHOWER/STORM POTENTIAL HELD OFF FOR THE PENINSULA UNTIL THE DAYLIGHT HOURS OF WEDNESDAY. MAY VERY WELL BE DEALING WITH SEA-FOG EXPANDING ONCE AGAIN AFTER SUNSET TUESDAY EVENING. WEDNESDAY...STRONG SHORTWAVE PASSES TO OUR NORTH PUSHING A COLD FRONT THROUGH THE AREA. THE SHORTWAVE PATH PROVIDES THE BEST SETUP FOR LARGE SCALE LIFT OVER THE NORTHERN HALF OF THE AREA...WHICH IS FAIRLY TYPICAL. HIGHEST RAIN CHANCES WILL EXIST FROM TAMPA BAY NORTHWARD ACROSS THE NATURE COAST. A MORE BROKEN BAND OF SHOWERS AND DECREASING RAIN CHANCES WILL EXIST FURTHER SOUTH LATE IN THE DAY WHEN THE BEST KINEMATICS WILL BE SHIFTING AWAY AS THE LOW LEVEL FRONTAL FOCUS ARRIVES. && .LONG TERM (WEDNESDAY NIGHT THROUGH NEXT SUNDAY)... MUCH OF THE EXTENDED FORECAST WILL BE PLAGUED BY RAIN CHANCES AS A SERIES OF UPPER-LEVEL IMPULSES MAINTAIN A TROUGH OVER THE EASTERN HALF OF THE NATION. GLOBAL MODELS ARE ACTUALLY IN QUITE GOOD AGREEMENT CONSIDERING THE COMPLEXITY AND EVENTUAL EVOLUTION OF THE UPPER-LEVEL PATTERN. THE TRICK WILL BE IN NAILING DOWN WHEN OUR BEST RAIN CHANCES WILL BE. LOW PRESSURE WILL BE PULLING AWAY FROM THE MID-ATLANTIC COAST WEDNESDAY NIGHT. A TRAILING COLD FRONT WILL BE WORKING ITS WAY SOUTHWARD ACROSS FLORIDA. THE ECMWF KEEPS AMPLE MOISTURE AND ENOUGH LIFT BEHIND THE FRONT TO CONTINUE RAIN CHANCES OVERNIGHT. THE GFS AND CANADIAN DRY US OUT A LITTLE...BUT ALSO SHOW A CHANCE OF SHOWERS THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. WILL CONTINUE LOW-END CHANCE POPS FOR NOW. ON THURSDAY...WEST TO SOUTHWEST FLOW OVER THE TOP OF OUR SHALLOW COOL AIRMASS WILL LEAD TO PLENTY OF CLOUDS AND MOST LIKELY SOME SHOWERS HERE AND THERE. USING A BLEND OF GUIDANCE YIELDS CHANCE POPS ONCE AGAIN...WHICH IS HIGHER THAN THE DRIER GFS/MEX. FRIDAY AND SATURDAY WILL BE TOUCH CALLS AS FAR AS RAIN POTENTIAL GOES. CERTAINLY FRIDAY HAS A GOOD CHANCE OF BEING WET SO INCLUDED 40 TO 50 PERCENT RAIN CHANCES FOR MOST OF THE AREA. SATURDAYS WEATHER WILL DEPEND ON THE TIMING AND DEPTH OF A RATHER IMPRESSIVE UPPER-LEVEL TROUGH FORECAST TO DIG SOUTHWARD INTO THE GULF. THE GFS IS WEAKER AND LESS AMPLIFIED WHICH RESULTS IN A SLOWER MOVING COLD FRONT THAT TAKES ITS TIME CLEARING OUT THE MOISTURE. THE ECMWF AND CANADIAN ARE DEEPER AND STRONGER...WITH THE FRONT CLEARING THE FLORIDA PENINSULA DURING THE DAY SATURDAY. ALL THREE OF THESE MODELS SHOW MUCH COLDER AIR POISED TO INVADE OUR REGION FROM THE NORTH. I AM INITIALLY LEAVING SOME RAIN CHANCES IN FOR SATURDAY FOR ALL BUT THE FAR NORTH...BUT IF THE GFS COMES ON BOARD WITH THE ECMWF...WE MAY BE ABLE TO SALVAGE A GOOD PART OF THE DAY. BY SUNDAY...ALL THE MODELS HAVE THE FRONT THROUGH THE AREA WITH COLD HIGH PRESSURE SETTLING IN OVER THE NORTHERN GULF. EVEN UNDER BRIGHT SUNSHINE ON SUNDAY...WE WOULD LIKELY STRUGGLE TO GET OUT OF THE 60S. THE 00Z ECMWF ACTUALLY SUPPORTS TEMPERATURES HOLDING IN THE 50S ALL DAY. I HAVE BASICALLY USED THE WARMER MEX NUMBERS FOR NOW...BUT I HAVE A FEELING WE WILL NEED TO TREND COLDER WITH TIME. IT IS WORTH NOTING THAT THERE IS THE POTENTIAL FOR FREEZING TEMPERATURES FOR MUCH OF THE INTERIOR AND NORTHERN ZONES SUNDAY NIGHT. WE WILL LOOK MORE AT THIS AS WE MOVE CLOSER TO THE EVENT. && .AVIATION... EXPECTING MAINLY VFR CONDITIONS THROUGH TODAY AND INTO THIS EVENING. SOME PATCHY FOG COULD BRING MVFR VISIBILITIES TO PGD AND LAL THIS MORNING. A MORE SIGNIFICANT FOG EVENT IS POSSIBLE AFTER 06Z TONIGHT WITH THE MOST FAVORED LOCATIONS BEING FROM SRQ NORTHWARD TO TPA AND PIE. && .MARINE... HIGH PRESSURE WILL CONTINUE TO RIDGE ACROSS THE FL PENINSULA AND EASTERN GULF WATERS THROUGH THIS AFTERNOON AND THEN RETREAT EASTWARD TONIGHT INTO TUESDAY IN RESPONSE TO THE DEVELOPMENT OF A WARM FRONTAL FEATURE AND SURFACE LOW ALONG THE NORTHERN GULF COAST. THIS LOW WILL DRIFT TO OUR NORTH DURING THE MIDWEEK PERIOD WITH A TRAILING COLD FRONT SHIFTING ACROSS THE EASTERN GULF WEDNESDAY AFTERNOON AND NIGHT. SOUTHEAST WINDS WILL APPROACH CAUTIONARY LEVELS AWAY FROM SHORE THIS MORNING AND THEN DIMINISH BELOW HEADLINE CRITERIA THIS AFTERNOON AND EVENING. WINDS WILL THEN ONCE AGAIN INCREASE TO CAUTIONARY LEVELS TUESDAY NIGHT AND WEDNESDAY AHEAD OF THE APPROACHING COLD FRONT. WINDS WILL SHIFT NORTH AND THEN QUICKLY NORTHEAST ON THURSDAY IN THE WAKE OF THIS FRONT. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS ARE EXPECTED THE NEXT SEVERAL DAYS AS SOUTHEAST TO SOUTHERLY FLOW BRING A SLOW INCREASE IN LOW LEVEL MOISTURE AND PREVENT CRITICAL LEVELS OF RELATIVE HUMIDITY. THE INCREASE IN LOW LEVEL MOISTURE IS EXPECTED TO INCREASE THE POTENTIAL FOR SEA FOG TO IMPACT LOCATIONS NEAR THE COAST...ESPECIALLY MANATEE COUNTY NORTHWARD THROUGH THE NATURE COAST. THIS POTENTIAL FOR LOCALLY DENSE FOG WILL BEGIN LATE TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... TPA 79 64 79 67 / 10 10 10 20 FMY 84 62 83 66 / 10 10 10 10 GIF 82 62 82 63 / 10 10 10 20 SRQ 79 60 79 67 / 10 10 10 10 BKV 81 57 80 64 / 10 10 10 40 SPG 80 64 79 67 / 10 10 10 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...BEACH HAZARDS STATEMENT UNTIL 2 PM EST THIS AFTERNOON FOR CHARLOTTE-LEE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1131 PM EST SUN FEB 10 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 215 PM EST SUN FEB 10 2013 A STRONG OCCLUDED SYSTEM WILL LIFT NORTHEAST ACROSS CENTRAL INDIANA LATE TONIGHT WITH THE RAIN EXPECTED TO END IN ITS WAKE. THEN...HIGH PRESSURE WILL BUILD IN FROM THE PLAINS AND SOUTHERN STATES THROUGH TUESDAY ALLOWING FOR DRY WEATHER AND TEMPERATURES CLOSER TO SEASONABLE. A SOUTHERN SYSTEM WILL BRING A CHANCE OF RAIN OR SNOW TO FAR SOUTH CENTRAL INDIANA TUESDAY NIGHT AND WEDNESDAY. THE NEXT CHANCE OF PRECIPITATION AFTER THAT WILL BE THURSDAY NIGHT THROUGH SATURDAY WITH RAIN OR SNOW POSSIBLE AS A LOW PRESSURE SYSTEM PIVOTS ACROSS THE LOWER GREAT LAKES. ABOVE NORMAL TEMPERATURES ON THURSDAY AHEAD OF THE SYSTEM WILL GIVE WAY TO BELOW NORMAL TEMPERATURES LATE IN THE WEEKEND BEHIND AN ASSOCIATED COLD FRONT. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 719 PM EST SUN FEB 10 2013 LOWERED POPS TO LOW CHANCE/SLIGHT CHANCE ACROSS THE AREA BASED ON RADAR MOSAIC AND HRRR FIELDS FOR THE NEXT SEVERAL HOURS. SOUNDINGS ARE LOOKING MORE LIKE SPRINKLES/DRIZZLE POSSIBLE FOR THE NEXT FEW HOURS AND THEN DRY WITH CLEARING SKIES AS A DRY SLOT CURRENTLY OVER MISSOURI/WESTERN ILLINOIS MOVES THROUGH THE AREA. WIND GUSTS COULD INCREASE A BIT WITH THE ARRIVAL OF THE DRY SLOT AND COULD MAX OUT AROUND 40 MPH. GOING LOWS IN THE MIDDLE 30S TO AROUND 40 SEEM A LITTLE COOL BUT STILL COULD SEE A GOOD DROP WITH CLOUDS BREAKING FROM THE DRY SLOT SO WILL LEAVE ALONE FOR NOW. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... ISSUED AT 215 PM EST SUN FEB 10 2013 MAIN CHALLENGE TO THE FORECAST WILL BE WINDS AND CLOUD COVER MONDAY ALONG WITH RESULTANT TEMPERATURES. ANOTHER MAIN ISSUE IS WHETHER TO BRING ANY POPS IN TUESDAY NIGHT AND WEDNESDAY AND IF SO HOW FAR NORTH TO BRING THEM AS AS MODELS ARE ALL OVER THE PLACE ON A WEAK SOUTHERN SURFACE SYSTEM WITH THE 12Z NAM BRINGING THIS SYSTEM AS FAR NORTH AS NORTHERN KENTUCKY BY 00Z THURSDAY WITH QPF ACROSS ALL OF THE FORECAST AREA WEDNESDAY. AND AT THE OTHER SPECTRUM THE GEM...ECMWF AND GFS HAVE IT WELL SOUTH NEAR THE GULF WITH QPF ONLY ACROSS OUR FAR SOUTH MAINLY WEDNESDAY. THE NAM IS AN OUTLIER WITH A SLOWER AND MUCH STRONGER UPPER SYSTEM AS IT CLOSES INTO AN UPPER LOW AND MOVES INTO SOUTHWESTERN INDIANA BY 00Z THURSDAY WHICH IS THE MAIN REASON FOR ITS FURTHER NORTH SURFACE LOW TRACK AND RESULT QPF. PER HPC HEMISPHERIC DISCUSSION THE NAM SOLUTION REGARDING A STRONGER LOW IS PLAUSIBLE BUT WITH ALL THE OTHER MODELS KEEPING THE SURFACE LOW WELL SOUTH...FAVOR THAT SOLUTION AND ALSO FAVOR A SLOWER SOLUTION PER MODEL TRENDS THAT WOULD FAVOR HOLDING OFF ON POPS UNTIL AFTER 06Z WEDNESDAY SOUTH CENTRAL AND CONTINUING THROUGH THE DAY WEDNESDAY. SMALL POPS ALSO LOOK LIKE THE WAY TO GO FOR NOW ESPECIALLY WITH THE UNCERTAINTY OF TIMING AND STRENGTH OF THE SYSTEM. GETTING BACK TO MONDAY...PLENTY OF LOW LEVEL MOISTURE IS PROGGED TO LINGER AS THE OCCLUDED LOW CENTER MOVES EAST ACROSS SOUTHERN ONTARIO. IN ADDITION...STRONG COLD AIR ADVECTION WILL BE TAKING PLACE. THUS...THINK THERE WILL BE A GOOD DEGREE OF CLOUD COVER AROUND AND FAVOR ADDING MORE CLOUD COVER THAN ALLBLEND AND KEEPING TEMPERATURES AT OR BELOW SIMILAR MOS. BUFKIT SUGGESTS WINDS TO 30 KNOTS AND GUSTS TO OVER 35 KNOTS POSSIBLE. SO...IT IS LOOKING LIKE NEAR ADVISORY CRITERIA. WILL COORDINATE AND MAKE LAST MINUTE DECISION ON WHETHER TO ISSUE AN ADVISORY OR A SPECIAL WEATHER STATEMENT. MONDAY NIGHT...SURFACE HIGH PRESSURE WILL BUILD IN FROM THE PLAINS AND SOUTHERN STATES...BUT MODEL TIME SECTIONS AND SOUNDINGS STILL HOLD ON TO A DECENT AMOUNT OF LOW LEVEL MOISTURE. SO...NOT EXPECTING FULL CLEARING...BUT SHOULD SEE SOME BREAKS. MOS TEMPERATURES VERY CLOSE...SO WILL STICK CLOSE TO THEM. FINALLY...TUESDAY...THE LOW LEVELS DRY UP WITH ONLY SOME HIGH CLOUDS AHEAD OF THE AFOREMENTIONED UPPER SYSTEM EXPECTED. WILL LEAN TOWARDS THE SLIGHTLY WARMER 12Z GFS MOS DUE TO THE LACK OF LOW CLOUDS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... ISSUED AT 244 PM EST SUN FEB 10 2013 THERE IS SIGNIFICANT VARIABILITY IN EXTENDED PERIOD AS SEVERAL LITTLE DISTURBANCES ROTATE AROUND A VERY BROAD UPPER LEVEL LOW. SO...WILL NOT DEVIATE MUCH FROM LATEST INITIALIZATION NUMBERS. THERE WILL BE PERIODIC CHANCES FOR PRECIP FROM THURSDAY NIGHT THROUGH SUNDAY...BUT PRECIP WILL FLUCTUATE BETWEEN RAIN/WINTRY MIX/SNOW UNTIL COLDER AIR SETTLES IN NEXT WEEKEND. WILL STICK WITH ALLBLEND IN REGARD TO TEMPS AND NOT DEVIATE. && .AVIATION /DISCUSSION FOR 110600Z TAF ISSUANCE/... ISSUED AT 1131 PM EST SUN FEB 10 2013 MVFR CEILINGS WILL IMPACT PRIMARILY KIND AND KBMG FOR THE FIRST COUPLE HOURS OF THE FORECAST...FOLLOWED BY VFR CONDITIONS. MVFR CEILINGS MAY REDEVELOP BY LATE MORNING AT KLAF. STRONG WIND GUSTS WILL IMPACT ALL TERMINALS THROUGH THE FORECAST PERIOD. CLEARING AREA ASSOCIATED WITH THE DRY SLOT MAKING STEADY EASTWARD PROGRESS AND SHOULD BE EAST OF BOTH KHUF AND KLAF BY 06Z. HAVE HELD ONTO MVFR CEILINGS AT KBMG AND KIND FOR A COUPLE HOURS BUT EXPECT SKIES CLEARING AT THESE SITES AS WELL BY 08Z. MAINLY CLEAR SKIES ARE THEN EXPECTED FOR MUCH OF THE REGION FOR THE REST OF THE OVERNIGHT WITH SOUTHWEST WIND GUSTS STEADILY INCREASING TO NEAR 30KTS BY DAYBREAK. STRATUS ASSOCIATED WITH THE COLD POOL WILL WORK BACK INTO KLAF TOWARDS DAYBREAK...GRADUALLY EXPANDING SOUTHEAST TO ENCOMPASS THE OTHER TERMINALS THROUGH LATE MORNING. MVFR CEILINGS ARE POSSIBLE AT KLAF BUT OTHERWISE EXPECT CLOUD HEIGHTS TO SETTLE BETWEEN 3-4KFT FOR THE AFTERNOON. WINDS WILL BE A SIGNIFICANT FACTOR ON AVIATORS MONDAY AS TIGHT PRESSURE GRADIENT AND STRONG WINDS ALOFT PERSIST AS DEEP LOW PRESSURE MOVES EAST ACROSS THE GREAT LAKES. PREDOMINANT WIND DIRECTION FOR THE AFTERNOON WILL BE 250-260 DEGREES WITH SUSTAINEDS AT 25 TO 30KTS AND GUSTS APPROACHING 40KTS. WINDS WILL BEGIN TO RELAX MONDAY EVENING AS HIGH PRESSURE BUILDS ACROSS THE REGION WITH SKIES SLOWLY CLEARING FROM THE SOUTHWEST. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...CP SHORT TERM...MK LONG TERM....TDUD AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS DES MOINES IA
357 AM CST MON FEB 11 2013 .SHORT TERM /TODAY/... MAIN FORECAST CONCERN TODAY IS WITH WINDS...AND LIGHT SNOW SHOWERS/FZDZ ACROSS NORTHERN IOWA. VERTICALLY STACKED LOW WILL CONTINUE TO PUSH EASTWARD THROUGH THE DAY AND PRESSURE GRADIENT BEGINS TO RELAX DURING THE AFTERNOON HOURS. NAM/GFS BUFR SOUNDINGS SUGGEST SOME LIGHT SNOW SHOWERS OR FLURRIES OVER NORTHERN IOWA THROUGH 18Z BUT RAP SHOWING LOSS OF ICE INTRODUCTION IN THE COLUMN PERIODICALLY DURING THE MORNING. SEVERAL CURRENT OBSERVATIONS ACROSS NORTHERN IOWA REPORTING DZ/UP SUGGESTING THIS IS ALREADY OCCURRING. FORCING REMAINS WEAK BUT LOOKS TO BE ENOUGH TO WARRANT THE MENTION OF PATCHY FZDZ ACROSS THE NORTHEAST THROUGH 18Z. WENT CLOSE TO GUIDANCE TODAY FOR MAX TEMPERATURES AS MODELS ARE IN GOOD AGREEMENT AND FELT NO REASON TO DEVIATE MUCH FROM THEM. THIS RESULTED IN TWEAKING TEMPS UP SLIGHTLY ACROSS THE SOUTH. NOT EXPECTING STRATUS TO CLEAR OUT ACROSS THE SOUTHWEST UNTIL AFTER 21Z WHEN THE PRESSURE GRADIENT BEGINS TO WEAKEN. KEPT OVERCAST OVER THE NORTH TO EAST THROUGH 00Z TUESDAY AS LOW LEVEL MOISTURE REMAINS PERSISTENT WITHIN THE CAA. .LONG TERM /TONIGHT THROUGH SUNDAY/... THE UPPER LOW PRESSURE WILL CONTINUE TO RACE OFF TO THE EAST TONIGHT AND BE NEAR MAIN BY 12Z TUESDAY MORNING. THIS WILL ALLOW MUCH DRIER AIR TO FILTER INTO THE STATE AS BROAD AREA OF HIGH PRESSURE SHIFTS EAST INTO THE MIDWEST. GENERAL TRENDS FOR TUESDAY AND WEDNESDAY ARE WARMER. THE DRY AIR WILL WARM NICELY ON TUESDAY UNDER SOUTHWEST FLOW. THE FLOW WILL BECOME MORE DOWN SLOPE ORIENTED TUESDAY NIGHT INTO WEDNESDAY AHEAD A VIGOROUS UPPER WAVE THAT WILL ARRIVE ALONG WITH AN ASSOCIATED COLD FRONT WEDNESDAY NIGHT. TEMPERATURES ON WEDNESDAY WILL BE IN THE MID TO UPPER 40S OVER THE CENTRAL AND SOUTH AND A FEW LOCATIONS MAY HIT 50 IF ENOUGH SUN IS AVAILABLE. THE UPPER WAVE WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. GUSTY NORTHWEST WINDS WILL KEEP COLD ADVECTION IN PLACE THROUGH THE DAY THURSDAY AND MAY HAVE SLOWLY FALLING TEMPERATURES DURING THE AFTERNOON. THE AIR MASS WITH THE SYSTEM WILL BE FAIRLY DRY WITH PWATS GENERALLY ONE QUARTER INCH OR LESS THEREFORE NO PRECIPITATION IS EXPECTED. ANOTHER UPPER WAVE WILL DROP INTO THE REGION THURSDAY NIGHT AND FRIDAY AND WILL HELP CARVE A LONG WAVE TROUGH OUT ACROSS THE NORTHERN PLAINS AND INTO THE EASTERN CONUS. THIS WILL BE ENHANCED AS HUDSON BAY UPPER LOW DROPS SOUTH INTO THE UPPER GREAT LAKES. 850 MB TEMPERATURES OVER THE STATE WILL BE AROUND -16C BY MID DAY FRIDAY. THE COLD AIR MASS WILL BE RELATIVELY DEEP AND WILL BE ABLE TO MIX WELL. THEREFORE DESPITE THE COLD AIR MASS...DEEP MIXING TO NEAR 850 MB WILL ALLOW TEMPERATURES RISE INTO THE UPPER TEENS TO UPPER 20S. SATURDAY AND SUNDAY WILL SEE GRADUAL MODERATION AS A WEAK RIDGE MOVES INTO THE STATE IN RESPONSE TO A STRONG SHORT WAVE DIVING INTO THE INTER MOUNTAIN WEST. && .AVIATION...11/06Z AREAS OF LIGHT SNOW WILL PERSIST ACROSS NORTHERN IOWA OVERNIGHT WITH A FEW FLURRIES IN THE SOUTH. VISIBILITIES WILL BE MVFR TO IFR IN THE NORTH WITH THE LIGHT SNOW BUT SHOULD IMPROVE TO VFR ON MONDAY AS THE PCPN ENDS. CEILINGS WILL REMAIN IN PLACE THROUGH MUCH OF MONDAY ACROSS THE FORECAST AREA WITH MVFR CEILINGS IN THE NORTH AND VFR CONDITIONS IN THE SOUTH. TIGHT PRESSURE GRADIENT WILL MAINTAIN STRONG WEST TO NORTHWEST WINDS OVERNIGHT INTO MONDAY BEFORE A GRADUAL WEAKENING INTO MONDAY EVENING AS THE GRADIENT RELAXES. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL NOON CST TODAY FOR IAZ004>007-015>017- 023>028-033>039-044>050-057>062-074-075-086. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1228 AM EST MON FEB 11 2013 ...Updated Aviation Discussion... .Forecast Update... Issued at 910 PM EST Sun Feb 10 2013 Not seeing much to increase forecast confidence as the evening wears on. Precip development has been limited at best, but the mesoscale models continue to generate chance POPs later this evening. Might otherwise be inclined to drastically lower POPs with this evening update, but the RUC and HRRR both seem to have a handle on what is out there now, and start to show development near the I-65 corridor around 03-04Z. Already updated to clean up evening wording and remove thunder, and lowered POPs to chance at that time. Otherwise the forecast has been left as-is and most tweaks for the rest of the evening will be in the grids. && .Short Term (Tonight - Monday Night)... Issued at 300 PM EST Sun Feb 10 2013 A vertically stacked low continues to churn across the Central Plains this afternoon. Out ahead of this low, a ridge has amplified over the Ohio Valley, allowing a warm and rather moist airmass to push north into the Ohio Valley. Showers and embedded thunderstorms have pushed into the western half of the CWA this afternoon. A notable weakening trend has occurred with this activity over the past few hours as it has pushed east, due to it outrunning the better elevated instability and the strongest forcing pushing north. This weakening trend will continue through the remainder of the afternoon, but much of the area still has a chance of seeing an isolated thunderstorm as the main line pushes east. Winds out ahead of this line have been breezy, especially across areas that received a break in the clouds early this afternoon. Simpson County for example, gusted to 37 knots as they broke out in some sunshine. However, winds should continue to slowly slacken as this system rolls through and saturates the column, limiting any mixing. Some of the stronger convection has mixed down some higher momentum air this afternoon, but the potential for any damaging gusts appears very low as a stout cap remains in place. After the main line rolls through late this afternoon into the early evening, attention will then turn to the southwest as another weak shortwave ejects out of the southwest flow aloft. Most high-res models are indicating some low-topped convective showers developing along the surface front as this wave rides up along it tonight. Therefore, will increase pops once again this evening into tonight to account for these showers. The surface front will clear the area and dry air will work into the region by Monday morning. The only issue on Monday will be the gusty wind potential, especially across southern Indiana and the northern Bluegrass. Currently have winds gusting to around 35 MPH during the afternoon hours, as mostly sunny skies and cold air advection aloft helps aid in mixing. These gusts are just below advisory criteria and the potential for an advisory across the northern CWA will need to be revisited in coming forecasts. With the expected deep mixing and a good amount of sunshine, have gone a bit above guidance for highs on Monday (upper 40s to middle 50s). Winds will begin to die down Monday night as a surface ridge pushes into the region. Lows Monday night will drop into the upper 20s and lower 30s, with mostly clear skies. .Long Term (Tuesday - Sunday)... Issued at 255 PM EST Sun Feb 10 2013 The first concern in the long term is, of course, the Tuesday night/Wednesday system. Looking at the models, the EC has had slightly better run-to-run consistency than the GFS, especially on Wednesday, with the path of the surface low that will be going by to our south Tuesday night/Wednesday. The EC also has been leading the way with verification of surface temperatures and dew points lately. Still, the EC isn`t perfect and it looks like the model is probably ejecting the low eastward too quickly. We will also need to dial in a bit of a northward correction to account for the possibility that the models might be taking this southern stream system a bit too far south. So, given all that, will go with a surface low path from Louisiana Tuesday evening to between Birmingham and Atlanta Wednesday morning to the VA/NC coast Wednesday evening. The upper trof associated with this system is a narrow appendage poking southwestward from the main upper trof well to our north. As a result it is quite far away from the polar vortex over the Canadian Archipelago and so there isn`t much cold air for this system to work with. So, despite the favorable track of the low to give us a snowstorm, it looks like we son`t have the requisite cold air and we should actually see rain in the south and a mix in the north. Of course, for a snowstorm one also needs a rich source of moisture. The GFS`s QPF is getting no real support from the EC, GEM, HPC, or GEFS and there is quite a bit of spread among the perturbation plumes in the GEFS (and SREF for that matter). So, won`t latch on to the GFS`s robust QPF numbers at this time and instead will go with more conservative amounts. Also supporting lower QPF values is a layer of surface-700hPa dry air that will have to be overcome Tuesday night before precipitation reaches the surface. In addition, the GFS tends to count virga as QPF. In the grids we have gone with 24-hour totals Tuesday night-Wednesday ranging from around a tenth of an inch in the north to a quarter of an inch far south. Even in the north where some snow will be possible, only a portion of that QPF will be snow. Ground temperatures will be warm from temperatures in the 45-50 degree range Tuesday afternoon, and highs Wednesday afternoon should get up to around 40. So, other than maybe a few tricky hours around the Wednesday morning commute, overall this system shouldn`t be too bad. Of course, we`ll need to keep an eye on it and the forecasts will surely evolve as we get closer to Tuesday night. A large upper trof will then dig into the Plains late in the week and invade the eastern half of the country over the weekend. This trof will have a direct connection to the main upper low over the Canadian Arctic and so will bring in colder air. Most of the precipitation associated with this trof will remain to our north in areas of better relative humidity and upper support. The best chance for precipitation for us will likely be with shortwave trofs diving down the backside of the trof. Those types of small-scale features are very difficult to accurately forecast so far out in the future, so will keep PoPs low at this time. Our warmest day should be Thursday with highs around 50. Once the late week upper trof comes in it will drop daily highs down into the 30s for the weekend. By Sunday morning we`ll probably dip into the teens, which is about ten degrees below normal for mid February. && .Aviation (06Z TAF Issuance)... Issued at 1228 AM EST Mon Feb 11 2013 Last little bit of light rain/drizzle is pushing into east-central KY. This will only impact LEX with lower cigs, which were experienced upstream. The back edge of the 1000-1500ft AGL cigs is currently across southern IL and western KY. If timed correctly, this should get into SDF and BWG within a couple of hours, and reach LEX around 10Z. All sites will improve to VFR, with breezy winds overnight keeping the atmosphere mixed. Expect mainly scattered Cu or Sc at the top of a relatively deep mixing layer later this afternoon. Winds will transition to west-southwest and be quite gusty, as a vertically stacked low meanders east across the Great Lakes today. Wind speeds will peak over 20 knots at BWG and perhaps just over 30 knots at SDF and LEX. Gusts should settle down around sunset, with speeds decreasing overnight as high pressure takes control. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........RAS Short Term.......KD Long Term........13 Aviation.........MJP
AREA FORECAST DISCUSSION...CORRECTION TO ADD AVIATION
NWS SHREVEPORT LA
146 AM CST MON FEB 11 2013 .UPDATE... KSHV 88D SHOWING SOME LIGHT RAIN ALONG I-20 FROM TYLER...CONFIRMED WITH ASOS...TO STILL VIRGA OVER LONGVIEW AND JUST SOUTH OF TEXARKANA. THE WATER VAPOR IMAGERY SHOWS A SPEED MAX OVER MEXICO...NEARING THE RIO GRANDE...BRINGING A BIT OF LIFT OVER NE TX BACK OVER THE COLD FRONT. WE HAVE UPDATED 6-12Z AND 12-18Z POP AND WEATHER GRIDS WITH LIGHT RAIN NORTH...AS T/TD SPREADS ARE STILL PRETTY HARDY AND WE WILL CONTINUE WITH OUR CHANCE SHOWERS IN THE FRONTAL VICINITY ALONG AND SOUTH OF I-20. NO OTHER CHANGES ATTM. /24/ && .AVIATION... MOSTLY VFR FLIGHT CATEGORIES EXPECTED THROUGH THE EARLY MORNING HOURS AROUND 11/14 UTC BUT WITH LIGHT RAIN OR EMBEDDED SHOWERS SPREADING RAPIDLY WEST TO EAST. CEILINGS WILL BE RUNNING AROUND 7 KFT TO 10 KFT WITH SOME LOWERING OF CLOUDS AT TIMES TO NEAR 5 KFT. ALL OF THE TERMINAL SITES ALONG AND SOUTH OF INTERSTATE 20 LOOK TO BE AFFECTED BY THE RAIN OR SHOWERS WITH VISIBILITIES NEAR 6 STATUTE MILES OR MORE THROUGH 11/14 UTC. THE CLOUD BASE WILL BE GRADUALLY LOWERING...TRANSITIONING TO MVFR/IFR NEAR MID DAY TO EARLY AFTERNOON...AND REMAINING AT THE LOWER CATEGORIES THROUGH THE END OF THE TERMINAL FORECAST PERIOD ENDING AROUND 12/06 UTC AND LIKELY TO 12/12 UTC. TERMINAL FORECAST FOR KTXK AND KELD WILL BE MORE LIKELY TO REMAIN AT VFR UNTIL 12/06 UTC. SURFACE WIND LIGHT AND VARIABLE OR NORTHERLY LESS THAN 7 KNOTS UNTIL AFTER 11/15 UTC WHEN THE WINDS BECOME NORTHEAST TO EAST 7 TO 11 KNOTS. WINDS WILL LOWER SLIGHTLY AFTER 12/00 UTC BUT REMAIN AROUND 6 TO 9 KNOTS. /06/ && .PREV DISCUSSION... /ISSUED 920 PM CST SUN FEB 10 2013/ DISCUSSION... SURFACE ANALYSIS THIS EVENING INDICATED THAT OUR FRONTAL BOUNDARY WAS STALLED NEAR A MEM...MLU...LCH LINE. MUCH DRIER AIR IN THE LOWER LEVELS OF THE ATMOSPHERE HAS INFILTRATED THE REGION FROM THE WEST BUT STILL DEALING WITH A FAIRLY MOIST PROFILE ACROSS OUR EXTREME EASTERN ZONES. ALSO BEGINNING TO SEE SOME REDEVELOPMENT OF WIDELY SCATTERED SHOWERS ACROSS OUR EXTREME EASTERN ZONES AS WELL. FOR THIS REASON...HAVE LEFT POPS PRETTY MUCH UNCHANGED THROUGH THE NIGHT ADVERTISING CHANCE POPS TO OUR SOUTH AND EAST. A QUICK LOOK AT THE 00Z NAM AS WELL AS THE LATEST RAP SHOWS THAT SCATTERED SHOWERS WILL BE POSSIBLE ALL NIGHT...MAINLY ACROSS OUR SOUTHEAST ZONES. THESE MODELS ALSO SUGGEST THAT THE FRONTAL BOUNDARY WILL FINALLY GET SHOVED SOUTH AND EAST OVERNIGHT WHICH WILL ALLOW FOR SOME DRIER AIR TO PUSH THROUGH AT LEAST OUT EASTERN MOST ZONES. HOWEVER...MID AND HIGH LEVEL CLOUDS SHOULD HANG ON FOR THE REMAINDER OF THE NIGHT ACROSS ALL BUT OUR EXTREME NW ZONES. DESPITE THE DRIER AIR...FEEL LIKE THE CLOUD COVER SHOULD HOLD TEMPS UP SOMEWHAT OVERNIGHT. MOS GUIDANCE WAS RUNNING A LITTLE TOO COOL WITH ITS 03Z TEMPS ACROSS A FEW SELECTED CITIES THIS EVENING SO HAVE BUMPED UP OVERNIGHT MINS JUST A DEGREE OR TWO ACROSS A FEW LOCATIONS. DID MAKE SOME ADJUSTMENTS TO DEWPOINTS GIVEN THE SLOWER INFILTRATION OF DRIER AIR INTO OUR EASTERN ZONES THIS EVENING AND SOME COSMETIC CHANGES TO SKY GRIDS. OTHERWISE...NO OTHER CHANGES WERE NECESSARY THIS EVENING. UPDATE OUT SHORTLY...13. AVIATION... MOSTLY VFR FLIGHT WEATHER TONIGHT AND MONDAY. HOWEVER...AREAS SOUTH AND EAST OF A KMLU TO KLFK LINE WILL EXPERIENCE LOW VFR CIGS... BETWEEN 4 AND 6 KFT...WITH ISOLATED SHOWERS AND TSTMS. EXPECT SOME BRIEF VISIBILITY RESTRICTIONS TO NEAR IFR IN THE STRONGER CONVECTION. THIS AREA OF LOW VFR CIGS AND CONVECTION WILL GRADUALLY SPREAD TO THE NORTH ON MONDAY...TO NEAR A KELD TO KTYR LINE BY 12/00Z. SURFACE WIND LIGHT AND VARIABLE TONIGHT...AND NORTHEAST 5 TO 10 KTS MONDAY. /14/ && .PRELIMINARY POINT TEMPS/POPS... SHV 49 61 46 57 40 / 20 20 50 60 20 MLU 51 59 46 55 41 / 40 40 50 60 40 DEQ 35 61 38 49 34 / 20 20 30 60 40 TXK 42 63 44 51 36 / 20 20 40 60 30 ELD 44 61 43 54 37 / 20 20 40 60 40 TYR 48 61 46 55 37 / 20 20 60 60 20 GGG 49 62 46 55 38 / 20 20 60 60 20 LFK 52 63 50 60 41 / 30 40 60 60 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 24/06
AREA FORECAST DISCUSSION
NWS DULUTH MN
1136 PM CST SUN FEB 10 2013 .AVIATION...06Z TAFS A MIXTURE OF IFR AND MVFR CONDITIONS COVERED THE NORTHLAND IN AREAS OF LIGHT SNOW...WITH AREAS OF FREEZING DRIZZLE ALSO OCCURRING. THE FREEZING DRIZZLE WAS FALLING MAINLY OVER SOUTHERN AREAS. THE PRECIPITATION SHOULD DIMINISH IN INTENSITY LATE TONIGHT OR MONDAY MORNING FOR MOST AREAS. VSBYS WILL RISE AS THE PRECIP INTENSITY DIMINISHES...AND CEILINGS WILL INCREASE THROUGH THE DAY AS WELL. CEILINGS MAY RISE TO OR SCATTER OUT AND BECOME VFR LATE IN THE PERIOD...MAINLY OVER WESTERN TAF SITES. && .PREV DISCUSSION... /ISSUED 938 PM CST SUN FEB 10 2013/ UPDATE... PRECIPITATION RATES HAVE DIMINISHED THIS EVENING FOR MUCH OF THE NORTHLAND...AND AS THAT HAS HAPPENED MORE FREEZING DRIZZLE HAS DEVELOPED. AN AREA OF HEAVIER PRECIPITATION WAS ROTATING NORTH TOWARD PRICE/SAWYER/WASHBURN COUNTIES AND MOST OBSERVATIONS UNDER THIS PRECIP HAS BEEN RAIN. GIVEN SURFACE TEMPS AND ROAD TEMPS ARE LIKELY AT OR BELOW FREEZING OVER MUCH OF THAT AREA...WE ADDED FREEZING RAIN TO THE FORECAST. THE HEAVY SNOW BAND WAS ROTATING THROUGH OUR EXTREME NORTH CENTRAL/NORTHWEST ZONES AS OF 930 PM...AND PRECIP RATES THERE SHOULD DIMINISH LATER THIS EVENING. WE KEPT ALL THE WARNINGS GOING...BUT DID MAKE SOME CHANGES TO THE EXPIRATION. WE CHANGED THE EXPIRATION OF MOST OF THE SOUTHERN HALF TO 6 AM MONDAY MORNING...HAVE THE NORTH HALF AT 18Z. THE SOUTH SHORE IS A BIT MORE OF A CHALLENGE. THE SETUP FOR LAKE EFFECT SNOW IS NOT IDEAL...AS STABILITY ISN`T AS LOW AS WE`D LIKE TO SEE. BASED ON THE POSSIBILITY OF LAKE ENHANCED SNOWFALL AS 850MB TEMPERATURES DROP IN THE AFTERNOON...WE KEPT THE EXPIRATION OF THE WARNING FOR BAYFIELD...ASHLAND AND IRON COUNTIES AT 6 PM MONDAY. THE DOUGLAS COUNTY WARNING WE CHANGED TO NOON MONDAY. LAKE ENHANCED SNOWFALL WILL NOT OCCUR THERE...BUT THERE IS A CHANCE FOR A GRAVITY WAVE INDUCED BAND OF SNOWFALL TO DEVELOP LATE TONIGHT INTO MONDAY MORNING AS WINDS TURN NORTH TO NORTHWEST. THE RAP IS SHOWING A FAIRLY STRONG GRAVITY WAVE SIGNAL...AND THE NAM BUFR SOUNDINGS SHOW A PRETTY GOOD INVERSION DEVELOPING AROUND 2300FT AGL BY 15Z. WE INCREASED SNOWFALL IN A BAND FROM NORTH CENTRAL/NORTHWEST DOUGLAS COUNTY INTO SOUTHWEST DOUGLAS/EASTERN CARLTON COUNTIES. LATER SHIFTS WILL HAVE TO MONITOR THIS CLOSELY AS WE MAY NEED TO INCREASE SNOWFALL THERE FURTHER. PREV DISCUSSION... /ISSUED 721 PM CST SUN FEB 10 2013/ UPDATE... THE AREA OF VERY HEAVY SNOW...WITH RATES IN EXCESS OF OF AN INCH PER HOUR HAS MOVED INTO FAR NORTHERN MINNESOTA. RADAR WAS SHOWING OTHER AREAS OF SNOW...MOST MUCH LIGHTER...FURTHER SOUTH. A FEW SPOTTERS HAVE REPORTED THE SNOW HAD ENDED FOR NOW...LIKE AT GURNEY. WE EXPECT SNOW TO CONTINUE TONIGHT WITH AMOUNTS RANGING FROM 3 TO 6 INCHES ACROSS THE FAR NORTH WHERE FORCING WILL LAST LONGER. AREAS FURTHER SOUTH WILL RANGE FROM 1 TO 4 INCHES TONIGHT...WITH FREEZING DRIZZLE OR FREEZING RAIN POSSIBLE OVER ABOUT THE SOUTHERN HALF OF THE NORTHLAND. IT WILL BE MOST LIKELY IN NORTHWEST WISCONSIN WHERE SOUNDINGS SHOW THE BEST FREEZING DRIZZLE SOUNDINGS. AN AREA OF HEAVIER PRECIPITATION WAS MOVING NORTH TOWARD NORTHERN WISCONSIN...AND OBSERVATIONS UNDER THIS AREA OF PRECIPITATION INDICATE MOSTLY RAIN...SO WE`LL HAVE TO WATCH CLOSELY AS IT MOVES FURTHER NORTH. AT THIS TIME...WE DID LEAVE ALL THE HEADLINES ALONE...WHICH EXPIRE AT 00Z TUE. WE WILL LIKELY BE ABLE TO CANCEL SOME OF THESE EARLIER...BUT WILL WAIT A BIT LONGER TO DO SO. ADDITIONAL SNOWFALL ON MONDAY LOOKS TO BE LIMITED...BUT WOULD LIKE TO SEE SOME NEW GUIDANCE BEFORE MAKING TO MANY DRASTIC CHANGES. THE EASTERN CWA COULD SEE THE SNOW LINGER LONGEST...AND ACCUMULATIONS COULD BE AN INCH OR TWO IN THE EAST. PREV DISCUSSION... /ISSUED 539 PM CST SUN FEB 10 2013/ AVIATION...00Z TAFS WIDESPREAD VLIFR/IFR CONDITIONS WILL OCCUR ACROSS MOST AREAS TONIGHT...WITH THE VLIFR CONDITIONS MOST WIDESPREAD ACROSS FAR NORTHERN MINNESOTA WHERE MANY OBSERVATIONS HAD 0.5SM OR LESS IN SNOW. THE SNOW INTENSITY WILL DIMINISH AS THE EVENING PROGRESSES FOR MOST AREAS OVERNIGHT...BUT THERE WILL STILL BE POCKETS OF HEAVIER SNOW. CONDITIONS WILL IMPROVE FURTHER ON MONDAY. EAST/NORTHEAST WILL VEER TO NORTH TO NORTHWEST BY 12Z. PREV DISCUSSION... /ISSUED 300 PM CST SUN FEB 10 2013/ SHORT TERM...TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE OVER NORTHERN IOWA WILL CONTINUE TO BRING SNOW TO MOST OF THE NORTHLAND THIS EVENING. SOME LIGHT FREEZING RAIN AND SLEET WILL STILL MIX IN WITH THE SNOW LATE THIS AFTERNOON OVER NORTHWESTERN WISCONSIN. NORTHERLY WINDS AT 15 TO 20 MPH...WITH A FEW GUSTS TO 25 MPH...ACROSS NORTHEASTERN MINNESOTA MAY LEAD TO SOME BLOWING AND DRIFTING OF THE SNOW. WINDS WILL BE STRONGER NEAR LAKE SUPERIOR. SNOW INTENSITY WILL COME DOWN A BIT AS THE LOW MOVES NORTHEASTWARD INTO WISCONSIN LATE TONIGHT. THE CENTER OF THE LOW WILL BE OVER THE UPPER PENINSULA OF MICHIGAN ON MONDAY MORNING AND LIGHT SNOW WILL PERSIST OVER THE AREA. ADDITIONAL ACCUMULATIONS DURING THE DAY ON MONDAY WILL GENERALLY BE UNDER AN INCH. WINDS WILL BECOME MORE NORTHWESTERLY ON MONDAY AND THERE WILL BE SOME LAKE ENHANCEMENT OF THE SNOW FOR THE GOGEBIC RANGE WHERE THERE COULD BE UP TO TWO ADDITIONAL INCHES OF SNOW DURING THE DAY. THE LOW PUSHES INTO EASTERN ONTARIO MONDAY NIGHT AND THE SNOW WILL END OVER MOST OF THE NORTHLAND EXCEPT FOR AREAS OF THE SOUTH SHORE OF LAKE SUPERIOR WHERE A FEW SNOW SHOWERS WILL LINGER DURING THE EVENING HOURS. HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE CENTRAL PLAINS LATE MONDAY NIGHT. LONG TERM...TUESDAY THROUGH SUNDAY. SOME LIGHT SNOW WILL BE POSSIBLE ACROSS THE AREA ON WEDNESDAY AFTERNOON...AS A LOW PRESSURE SYSTEM MOVES TO THE FARGO AREA BY 00Z THURSDAY. THE LOW WILL THEN MOVE ACROSS CENTRAL MN AND INTO NORTHERN TO CENTRAL WISCONSIN BY 12Z THURSDAY. HAVE INCREASED POPS ACROSS THE AREA FOR WEDNESDAY NIGHT AND THURSDAY AS THE MODELS ARE COMING INTO BETTER AGREEMENT CONCERNING THIS SYSTEM. THE GFS CONTINUES TO BE STRONGER THAN THE ECMWF...BUT YESTERDAY THE ECMWF DID NOT EVEN INDICATE THIS SYSTEM SO IT IS LIKELY LATCHING ONTO IT BETTER. COLDER AIR WILL DRAG SOUTHWARD BEHIND THE DEPARTING SYSTEM ON THURSDAY AND FRIDAY. GENERALLY DRY AND COOLER WEATHER IS THEN IN STORE FOR SATURDAY AND SUNDAY. OVERALL NOT TOO MUCH IN THE WAY OF PRECIPITATION THIS PERIOD WITH THE EXCEPTION OF A FEW INCHES OF SNOW BEING POSSIBLE MID WEEK. TEMPS WILL BE ABOVE NORMAL FOR MUCH OF THE EXTENDED...BUT IT WILL BE A BIT COOLER FOR THE WEEKEND. AVIATION.../18Z TAF ISSUANCE/ A WINTER STORM WILL AFFECT THE NORTHLAND DURING THE TAF PERIOD. THE STORM WILL BRING AN INCREASE IN SNOW AND POSSIBLY SOME SNOW/ICE MIX IN EASTERN AREAS. CIGS AND VSBYS WILL GENERALLY BE IN THE IFR/LIFR/VLIFR RANGE THROUGHOUT THE PERIOD...BUT TRANSITIONING TO MORE OF AN MVFR SITUATION ON MONDAY MORNING. SNOW WILL COME DOWN VERY HARD AT TIMES...WITH VSBYS LESS THAN A QUARTER MILE. && .POINT TEMPS/POPS... DLH 23 25 9 26 / 100 80 10 0 INL 18 22 7 26 / 100 90 10 0 BRD 24 26 9 27 / 100 80 10 0 HYR 26 29 10 27 / 100 90 10 0 ASX 27 29 11 27 / 100 90 20 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL NOON CST MONDAY FOR MNZ010>012- 018>021. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR MNZ025-026- 033>038. WI...WINTER STORM WARNING UNTIL NOON CST MONDAY FOR WIZ001. WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR WIZ006>009. WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR WIZ002>004. && $$ SHORT TERM...MELDE AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1140 PM CST SUN FEB 10 2013 .UPDATE... .DISCUSSION... SATELLITE...SFC OBS...RADAR AND A REPORTS FROM LAW ENFORCEMENT SUGGEST BLIZZARD CONDITIONS WILL CONTINUE FOR A FEW MORE HOURS ACROSS THE NORTHEAST CORNER OF THE FCST AREA. THE RUC SHOWS THE LOW LEVEL CLOUD EXITING THE FCST BY AROUND 10Z OR SO. THIS SHOULD ALLOW FOR LESS VERTICAL MIXING AND SLOWER WIND SPEEDS. A WINTER WEATHER ADVISORY CONTINUES OVERNIGHT FOR ALL AREAS AFFECTED BY THE BLIZZARD. STRONG WINDS IN SOME AREAS WILL CONTINUE TO BUILD DRIFTS AND PRODUCE NEAR WHITE OUT CONDITIONS IN SPOTS. IN OTHER AREAS...SOME RURAL UNIMPROVED ROADS ARE PARTIALLY OR COMPLETELY BLOCKED BY HARD PACKED DRIFTS. && .PREV DISCUSSION... /ISSUED 1107 PM CST SUN FEB 10 2013/ UPDATE... AVIATION... FLIGHT CONDITIONS ACROSS NCNTL NEB EAST OF KVTN WILL GRADUALLY IMPROVE FROM IFR TO VFR AS LOW CLOUDINESS EXIT EAST OVERNIGHT. VFR IS EXPECTED ALL AREAS BY 12Z. VFR IS EXPECTED ALL AREAS THEREAFTER THROUGH 06Z MONDAY EVENING. PREV DISCUSSION... /ISSUED 923 PM CST SUN FEB 10 2013/ UPDATE... DISCUSSION... BLIZZARD CONDITIONS HAVE DECREASED WEST OF THEDFORD AND CODY. A WINTER WEATHER ADVISORY FOR BLOWING SNOW IS NOW IN EFFECT UNTIL 8 AM CST. TRAVEL ON UNIMPROVED ROADS WILL REMAIN HAZARDOUS OVERNIGHT DUE TO DEEP DRIFTS PARTIALLY OR COMPLETELY BLOCKING SOME ROADS. THESE DRIFTS WILL CONTINUE TO BUILD OVERNIGHT IN SOME AREAS AS WINDS LOCALLY CONTINUE AT SPEEDS UP TO 25 MPH. PREV DISCUSSION... /ISSUED 717 PM CST SUN FEB 10 2013/ UPDATE... DISCUSSION... A QUICK FIX TO INCREASE WIND SPEEDS IN THE BLIZZARD WARNED AREA. FCST WINDS SHOULD BE CLOSER TO THE OBSERVED SPEEDS WITH THIS UPDATE. PREV DISCUSSION... /ISSUED 705 PM CST SUN FEB 10 2013/ UPDATE... DISCUSSION... SKIES HAVE CLEARED SUFFICIENTLY FOR WIND SPEEDS TO DECREASE WELL BELOW 30 MPH ACROSS SOUTHWEST NEBRASKA WHERE THE WIND ADVISORY WAS FLYING. THE WIND ADVISORY IS CANCELLED. NORTHWEST WINDS OF 15 TO 25 MPH ARE EXPECTED THE REST OF TONIGHT. PREV DISCUSSION... /ISSUED 520 PM CST SUN FEB 10 2013/ UPDATE... AVIATION... VFR IS EXPECTED TO CONTINUE SPREADING EAST THROUGH THE FCST AREA THIS EVENING. SIGNIFICANT WRAP AROUND SNOW AND LOW CIGS MAY CONTINUE AROUND KONL UNTIL AROUND MIDNIGHT...PERHAPS A FEW HOURS LATER WITH WINDS REMAINING STRONG. WINDS IN THE VFR AREA WILL DECREASE SUBSTANTIALLY AT SUNSET WHILE ANY AREAS WITH MVFR WILL SEE STRONG WINDS CONTINUING. VFR IS EXPECTED ALL AREAS MONDAY. PREV DISCUSSION... /ISSUED 351 PM CST SUN FEB 10 2013/ SYNOPSIS... INTENSE LOW PRESSURE WAS LOCATED WEST OF SIOUX CITY IOWA THIS AFTERNOON WITH VERY STRONG NORTHWESTERLY WINDS PRESENT ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. WIND GUSTS WERE ON THE ORDER OF 40 TO 55 MPH THIS AFTERNOON. WITH SNOW CONTINUING IN THE CENTRAL AND NORTHERN SANDHILLS...AS WELL AS NORTH CENTRAL NEBRASKA...BLIZZARD OR NEAR BLIZZARD CONDITIONS CONTINUE TO PERSIST ATTM. SNOWFALL ACROSS SOUTHWESTERN NEBRASKA HAS DIMINISHED OVER THE PAST COUPLE OF HOURS...HOWEVER...SOME BLOWING SNOW ISSUES CONTINUE...WITH GROUND BLIZZARD CONDITIONS CONTINUING IN KEITH AND GARDEN COUNTIES. ELSEWHERE...ACROSS SOUTHWESTERN NEBRASKA...VSBYS WERE IN THE 1 TO 3 MILE RANGE. A PLETHORA OF WINTER HEADLINES CONTINUE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...AND THESE WILL BE EVALUATED NEAR FCST ISSUANCE. SHORT TERM...(THIS EVENING THROUGH MONDAY) 990 MB SFC LOW PRESSURE CENTER IS LOCATED IN NORTHWEST IOWA AND CONTINUES TO MOVE EAST NORTHEAST AWAY FROM THE AREA. PEAK WINDS ARE OCCURRING NOW AND SHOULD BEGIN TO SLOWLY DIMINISH THROUGH THE EVENING. TRAFFIC CAMS AND CALLS TO AND FROM LAW ENFORCEMENT OFFICIALS AROUND THE REGION INDICATE THAT THE BLIZZARD WARNING CAN BE DOWNGRADED TO A WINTER WEATHER ADVISORY ACROSS THE SOUTHERN TIER...INCLUDING THE INTERSTATE CORRIDOR. WILL KEEP IT GOING ACROSS NORTHERN NEBRASKA AND THE SANDHILLS...WHERE THEY ARE STILL EXPERIENCING SOME LIGHT FALLING SNOW AND POOR VISIBILITY...DOWN TO 200 YARDS IN SOME CASES. SNOWFALL TOTALS RANGED FROM 4 TO 10 INCHES...ABOUT WHAT WAS FORECASTED. PEAK WIND SPEEDS OF 57 MPH ALSO OCCURED. CONDTITONS SHOULD GRADUALLY IMPROVE FROM WEST TO EAST THROGH THE NIGHT. MONDAY SHOULD SEE WINDS CONTINUE TO DIMINISH AND SKIES CLEAR...BUT HIGH TEMPERATURES WILL BE CHILLY IN THE UPPER 20S TO MID 30S. LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) MAIN FORECAST CHALLENGES DEAL WITH TEMPERATURES AND THE POSSIBILITY OF LIGHT SNOW THURSDAY INTO FRIDAY. LIGHT WESTERLY WINDS...FRESH SNOW COVER AND MOSTLY CLEAR SKIES MONDAY NIGHT...WILL SET THE STAGE FOR COLD TEMPERATURES TUESDAY MORNING. UNDERCUT GUIDANCE ACROSS SNOW COVERED AREAS...AND WENT WITH LOWS NEAR ZERO IN THE PLATTE RIVER VALLEY. ON TUESDAY...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL SLIDE EAST ACROSS THE SRN PLAINS. PRECIPITATION AND CLOUDS ARE EXPECTED TO REMAIN SOUTH OF THE FORECAST AREA. EVEN WITH FULL SUN...TEMPS WILL STRUGGLE TO GET OUT OF THE HIGH 30S WITH LIGHT WINDS...SNOW COVER...AND H85 TEMPS OF -2 TO -4 C. TEMPERATURES TUESDAY...WILL APPROACH THE LOWER 40S IN ADVANCE OF AN APPROACHING CLIPPER SYSTEM...WHICH WILL ARRIVE ON WEDNESDAY NIGHT. WINDY AND COLDER TEMPERATURES ARRIVE ON THURSDAY AS A CLIPPER TRAVERSES THE EASTERN DAKOTAS AND UPPER MISSISSIPPI VALLEY. THE MEX AND ECE GUIDANCE FEATURES A WIDE SPREAD IN TEMPS WITH LOWER 30S NORTHEAST TO THE MIDDLE 40S IN THE SOUTHWEST. DECIDED TO UNDERCUT THESE NUMBERS BASED ON FCST H85 TEMPS AND RESIDUAL SNOW COVER. COLDER TEMPERATURES WILL PUSH INTO THE REGION ON FRIDAY AS ARCTIC HIGH PRESSURE BUILDS INTO NORTHEASTERN NEBRASKA. HIGHS FRIDAY WILL BE IN THE 20S TO THE LOWER 30S OVER FAR SOUTHWESTERN NEBRASKA. ON SATURDAY AND SUNDAY...RIDGING WILL BEGIN TO BUILD EAST INTO THE CENTRAL CONUS...AS A TROUGH OF LOW PRESSURE PUSHES INTO FAR WESTERN CANADA AND THE NWRN CONUS. MORE SEASONAL HIGHS ARE FORECAST SATURDAY AND SUNDAY WITH READINGS IN THE 40S EXPECTED. AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) BLOWING SNOW WILL CONTINUE THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS AT THE KLBF TERMINAL...AND THROUGH LATE EVENING AT THE KVTN TERMINAL...WITH VSBYS OF 3 TO 5 SM AT THE KLBF TERMINAL...AND PERIODIC VSBYS DOWN TO 1/2 SM AT THE KVTN TERMINAL. WINDS ARE EXPECTED TO DIMINISH AFTER 03Z TONIGHT AT THE KLBF TERMINAL AND AFTER 06Z FOR THE KVTN TERMINAL. IN THE MEANTIME...NORTHWESTERLY WINDS SUSTAINED AT 30 KTS...WITH GUSTS OVER 40 KTS WILL BE LIKELY ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA THROUGH EARLY THIS EVENING. CIGS WILL RANGE FROM 1000 TO 4000 FT AGL THROUGH LATE THIS AFTERNOON. CIGS WILL LIFT TO ABOVE 12000 FT AGL AT THE KLBF TERMINAL BY LATE EVENING...AND TOWARD SUNRISE MONDAY AT THE KVTN TERMINAL. && .LBF WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL 8 AM CST /7 AM MST/ MONDAY FOR NEZ004-005-008-022>029-035>038-056-057-059-094. BLIZZARD WARNING UNTIL 4 AM CST MONDAY FOR NEZ006-007-009-010. && $$ SHORT TERM...CDC LONG TERM...BROOKS AVIATION....CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1050 PM CST SUN FEB 10 2013 .UPDATE...UPDATED THE FORECAST FOR THE EXPIRATION OF THE WIND AND WINTER WEATHER ADVISORIES AS WIND HAS GENERALLY DECREASED SOME...BUT WE COULD GET SOME HEALTHY GUSTS WELL INTO THE OVERNIGHT. TWEAKED UP HOURLY TEMPERATURES A BIT WITH THE INCREASED WIND SPEED AND ALSO ADDED SOME FLURRIES OVER THE NORTHEASTERN THIRD FOR THE OVERNIGHT AS THE MOSAIC RADAR LOOP INDICATES. && .AVIATION...06Z KGRI TAF. STRONG NORTHWEST WIND WILL BE THE PRIMARY CONCERN FOR THE FIRST SEVERAL HOURS OF THE FORECAST...THEN SUBSIDE SOMEWHAT BY SUNRISE...BUT CONTINUE TO BE BRISK INTO MONDAY. CEILINGS WILL BE SCATTERING AND COULD FLUCTUATE BETWEEN VFR AND MVFR CEILING FOR THE FIRST HOUR OR TWO AS AN AREA OF LOW PRESSURE CONTINUES TO PULL NORTHEAST...BUT SHOULD BE PRIMARILY WITHOUT A CEILING FROM THE GET GO. && PREV DISCUSSION... /ISSUED 259 PM CST SUN FEB 10 2013/ SHORT TERM...TODAY THROUGH MONDAY NIGHT. MAIN CONCERN DURING THIS TIME PERIOD WILL BE THE WINDS BEHIND THE SURFACE LOW. OUR NORTHERN COUNTIES...WHERE SNOWFALL OCCURRED EARLIER TODAY...WILL LIKELY RUN INTO VISIBILITY RESTRICTIONS AS BLOWING SNOW OCCURS THROUGH THE EARLY EVENING HOURS. ORD HAS EXPERIENCED VISIBILITIES BETWEEN ONE AND TWO MILES SINCE ABOUT 18Z TODAY...BUT EARLIER TODAY CONDITIONS WERE BELOW HALF A MILE. ALSO...THERE WILL BE A SLIGHT CHANCE FOR SNOW THROUGH THE REMAINDER OF TODAY...MAINLY FOR OUR NORTHERN COUNTIES. AT 20Z...THE RAP INDICATED A 500MB LOW APPROXIMATELY CENTERED OVER SIOUX FALLS SOUTH DAKOTA. THE SURFACE LOW WAS DIRECTLY UNDER THE UPPER LEVEL LOW...RESULTING IN A STACKED TROUGH WHICH IS NOW EXITING THE CENTRAL PLAINS. BEHIND THE SURFACE LOW...HEIGHT RISES ARE RESULTING IN A SHARP PRESSURE GRADIENT OVER THE OUTLOOK AREA. NORTHWESTERLY WIND SPEEDS OF 30 MPH WERE EXPERIENCED OVER NEARLY THE ENTIRE CWA. GUSTS WERE REACHING THE MID TO UPPER 40S...WITH ONLY A COUPLE SITES REACHING 50 MPH. THE WINTER WEATHER ADVISORY FOR BLOWING SNOW WILL CONTINUE UNTIL 9 PM TONIGHT TONIGHT. THIS WILL LIKELY NEED TO BE CONVERTED TO A WIND ADVISORY IF VISIBILITIES RECOVERY LATER TODAY. THE WIND ADVISORY COUNTIES UNTIL 9 PM...AS MODELS ARE NOT DEPICTING ANY LETTING UP OF THE PRESSURE GRADIENT BEFORE THEN. THE WIND ADVISORY MAY NEED TO BE EXTENDED FOR OUR EASTERN COUNTIES IF CONDITIONS DO NO EASE UP LATER TONIGHT. WIND SPEEDS WILL BEGIN TO RELAX AFTER MIDNIGHT AS THE PRESSURE GRADIENT EASES OVER THE REGION. A NORTHWESTERLY WIND COMPONENT WILL BE REALIZED OVER THE ENTIRE SHORT TERM PERIOD. HIGH TEMPERATURES FOR TOMORROW WILL BE RELATIVELY CLOSE TO NORMAL FOR THIS TIME OF YEAR. ON THE OTHER HAND...LOW TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR. LONG TERM...MONDAY NIGHT THROUGH SUNDAY...WEAK ZONAL FLOW IS EXPECTED ACROSS THE REGION TO BEGIN THE EXTENDED PERIODS AS THE VIGOROUS UPPER LEVEL LOW THAT MOVED ACROSS THE LOCAL AREA THIS MORNING APPROACHES THE EASTERN SEABOARD AND A SECOND UPPER LEVEL LOW TRACKS ACROSS THE DESERT SOUTHWEST. AT THE SAME TIME A WEAK UPPER LEVEL SHORTWAVE IS EXPECTED TO EXTEND ACROSS THE LOCAL AREA FROM THE NORTH...PROVIDING AMPLE MID LEVEL CLOUD COVER DURING THE OVERNIGHT HOURS MONDAY INTO TUESDAY MORNING...BUT WITH MINIMAL FORCING AND VERY LIMITED LOW LEVEL MOISTURE...DO NO EXPECT ANY SORT OF PRECIPITATION UNDER THIS SCENARIO. AS THE AFOREMENTIONED UPPER LEVEL ACROSS THE DESERT SOUTHWEST MOVES INTO THE SOUTHERN PLAINS TUESDAY AFTERNOON...THE UPPER LEVEL FLOW PATTERN WILL BECOME MORE AMPLIFIED...AS A RIDGE OF HIGH PRESSURE WORKS ITS WAY TOWARDS THE WEST COAST. THIS WILL ESTABLISH A NORTHWESTERLY FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS BY WEDNESDAY...WITH MULTIPLE QUICK PASSING UPPER LEVEL DISTURBANCES EXPECTED TO TRAVERSE THE PLAINS. WITH THE QUICK MOVING NATURE OF THESE DISTURBANCES AND DRY LOW LEVELS OF THE ATMOSPHERE...DO NOT THINK MORE THAN FLURRIES WILL BE REALIZED THROUGH THE END OF THE WEEK...WITH THE BEST GUEST AT TIMING BEING DURING THE DAY ACROSS THE NORTHWEST THURSDAY...AND ACROSS ALL AREAS ON FRIDAY. THE FIRST OF THESE DISTURBANCE WILL BE ACCOMPANIED BY A SURFACE COLD FRONT...WHICH IS EXPECTED TO KNOCK TEMPERATURES DOWN 10+ DEGREES F ON THURSDAY...WITH THIS COOLER...YET SEASONAL AIRMASS THEN EXPECTED TO PERSIST ACROSS THE LOCAL ARE THROUGH THE END OF THE WEEK. AHEAD OF THE FRONT...WEDNESDAY AFTERNOON APPEARS TO BE THE NICEST DAY OF THE WEEK...WITH A LIGHT DOWNSLOPING COMPONENT TO THE WINDS LIKELY HELPING TEMPERATURES CLIMB TO NEAR 50 DEGREES. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE/AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS BUFFALO NY
448 AM EST MON FEB 11 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE INTO SOUTHERN QUEBEC TODAY. THIS WILL BRING A PERIOD OF RAIN EARLY TODAY...WITH SOME FREEZING RAIN ACROSS THE INTERIOR VALLEYS AND A WINTRY MIX EAST OF LAKE ONTARIO. AFTER THIS WINDS WILL INCREASE BEHIND AN ASSOCIATED COLD FRONT...CAUSING RAIN SHOWERS TO CHANGE TO SNOW LATER TODAY AND TONIGHT. && .NEAR TERM /THROUGH TONIGHT/... THERE WILL BE SEVERAL TRANSITIONS TODAY...AS A SERIES OF BOUNDARIES ASSOCIATED WITH LOW PRESSURE ACROSS THE UPPER LAKES INFLUENCES OUR WEATHER. THROUGH THIS MORNING...THE MAIN SOURCE OF LIFT WILL COME FROM AN AREA OF WARM AIR ADVECTION ALOFT. RADAR TRENDS SUGGEST STEADIEST RAINS WILL FOCUS NORTH OF A BUFFALO TO ROCHESTER LINE...WITH LIGHTER QPFS ACROSS THE SOUTHERN TIER. FORTUNATELY...TEMPERATURES SHOULD REMAIN JUST ABOVE FREEZING IN THESE LOCATIONS...WITH DOWNSLOPING OFFSETTING EVAPORATIONAL COOLING. A FREEZING RAIN ADVISORY REMAINS IN EFFECT ACROSS THE INTERIOR...WHERE TEMPERATURES AT 400 AM ARE IN THE LOWER TO MID 30S. HOWEVER...WITH DEW POINTS IN THE 20S EXPECT EVAPORATIONAL COOLING TO DROP TEMPERATURES A FEW DEGREES AS THE RAIN STARTS. RADAR TRENDS ARE MUCH BETTER CAPTURED BY THE HRRR THAN THE NAM/GFS/RGEM WHICH ARE TOO HIGH ON QPF ACROSS THE SOUTHERN TIER. FOLLOWING THIS...EXPECT A FEW HUNDREDTHS OF AN INCH OF QPF ACROSS INTERIOR PORTIONS OF WESTERN NEW YORK...HOWEVER THIS WILL FALL AS FREEZING RAIN IN MANY SPOTS...SO WILL KEEP THE ADVISORY UP. STEADIER PRECIPITATION WILL MOVE EAST OF LAKE ONTARIO THROUGH DAYBREAK...BRINGING THE GREATEST ICING POTENTIAL FOR THIS EVENT. THERE WILL BE MODEST DOWNSLOPE WARMING HERE TOO...BUT WITH DRY AND COOLER AIR IN PLACE EXPECT AROUND A TENTH OF AN INCH OF FREEZING RAIN GLAZE...WITH PERHAPS SOME LIGHT SNOW OR SLEET ACCUMULATION. ALL OF THIS PRECIPITATION SHOULD LIFT FROM SW- NE...ENDING ACROSS WESTERN PORTIONS AROUND DAYBREAK...AND LATE THIS MORNING EAST OF LAKE ONTARIO. THIS SHOULD PROVIDE A BRIEF LULL IN THE ACTION UNTIL THE NEXT BOUNDARY CROSSES. THE NEXT PHASE OF THIS EVENT WILL COME AS THE COLD/OCCLUDED FRONT ASSOCIATED WITH THE UPPER LOW MOVES ACROSS THE REGION. IT WILL ENTER WESTERN NEW YORK AROUND NOON...SWEEPING TO EAST OF LAKE ONTARIO AROUND SUNSET. THIS WILL BRING MAINLY SCATTERED RAIN SHOWERS...BUT ITS MORE SIGNIFICANT IMPACT WILL BE AN INCREASE IN WINDS BEHIND IT. GUSTY SOUTHWESTERLY WINDS WILL PICK UP FIRST ACROSS THE NIAGARA FRONTIER...SPREADING TO THE EAST LATE AFTERNOON AND EVENING. THE LOW IS NOT PARTICULARLY DEEP...NOR IS THE COLD ADVECTION TOO STRONG. WITH ONLY MODEST PRESSURE RISES DONT EXPECT EXTREMELY DEEP MIXING TO TAP THE 50 KNOTS ALOFT...BUT STILL SUFFICIENT TO BRING ADVISORY CRITERIA GUSTS OF 45 TO 50 MPH LATER IN THE AFTERNOON. THE 230-240 DEGREE WIND DIRECTION FAVORS THE STRONGER WINDS FROM THE LAKE ERIE SHORE ACROSS THE NIAGARA FRONTIER TO ROCHESTER. LATER IN THE EVENING WINDS BECOME MORE WESTERLY...WHICH WILL SPREAD STRONGER WINDS INTO THE INTERIOR SOUTHERN TIER AND WESTERN FINGER LAKES. A WIND ADVISORY REMAINS IN EFFECT ACROSS ALL BUT THE EASTERN LAKE ONTARIO REGION. BEHIND THE COLD FRONT...THE UPPER LEVEL TROF ASSOCIATED WITH THE LOW WILL MOVE ACROSS THE REGION. THIS WILL USHER IN COLDER AIR BOTH ALOFT AND AT THE SURFACE. ITS IMPORTANT TO NOTE THAT THIS IS NOT A VERY COLD AIR MASS...WITH 850 MB TEMPERATURES LIKELY TO DROP TO AROUND -10C TONIGHT. THIS IS NOT REALLY COLD ENOUGH FOR PURE LAKE EFFECT...BUT WITH SIGNIFICANT MOISTURE ASSOCIATED WITH THE UPPER TROF...AND SOME UPSLOPE ENHANCEMENT...EXPECT THERE WILL BE SOME SNOW EAST AND NORTHEAST OF THE LAKES TONIGHT. GIVEN THE MINIMAL CONTRIBUTION FROM LAKE INSTABILITY...EXPECT QPFS ARE A BIT OVERDONE BY THE NAM/RGEM WITH THE UPSLOPE...BUT DO FEEL SOME PRECIPITATION IS CERTAINLY REASONABLE. SNOW RATIOS SHOULD NOT BE GREAT GIVEN THE MARGINALLY COLD AIR...WITH 2 OR 3 INCHES SNOW ACCUMULATION LIKELY ON THE TUG HILL TONIGHT...AND A BIT LESS ON THE CHAUTAUQUA RIDGE. IF THERE WERE NOT ALREADY ADVISORIES IN PLACE...THIS PORTION OF THE EVENT COULD REQUIRE A SNOW ADVISORY...BUT WITH A BREAK BETWEEN THE TWO WILL HANDLE THIS AS TWO EVENTS RATHER THAN COMPLICATING THE ISSUE. THIS IS A CHALLENGING EVENT...BECAUSE IF MODEL QPF DOES VERIFY OR IF SNOW RATIONS EXCEED 20 TO 1...THEN THIS COULD ACTUALLY APPROACH WARNING CRITERIA ON THE TUG HILL. AT THIS TIME...NEITHER OF THESE SCENARIOS APPEAR LIKELY. SNOWS WILL BE LESS OFF LAKE ERIE...BUT THE SW FLOW MAY BRING AN INCH OR SO ACROSS THE BUFFALO METRO AREA...WITH LOCALLY HIGHER AMOUNTS ACROSS THE BOSTON HILLS AND CHAUTAUQUA RIDGE. OTHERWISE...TEMPERATURES WILL WARM BRIEFLY TODAY...ESPECIALLY IN THE FINGER LAKES REGION...WITH HIGHS IN THE 40S AHEAD OF THE FRONT. WINDS WILL BE GUSTY FOR A FEW HOURS THROUGH DAYBREAK ALONG I-90 FROM THE NY/PA LINE TO BUFFALO AS DOWNSLOPING RESULTS IN GUSTS UP TO 40 MPH. 925 MB WINDS WILL DIMINISH AFTER 12Z...DIMINISHING WINDS HERE UNTIL THE FRONT MOVES THROUGH. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... ON TUESDAY A SURFACE COLD FRONT WILL BE WELL TO THE EAST WITH COLD AIR ADVECTING ACROSS THE EASTERN GREAT LAKES. THIS WILL BE A MARGINAL SET UP FOR LAKE EFFECT SNOW...WITH THE MAIN FORCING MECHANISM BEING MORE THE UPSLOPE FLOW OVER HIGHER TERRAIN EAST OF BOTH GREAT LAKES. TEMPERATURES AT 850 HPA WILL DROP TO AROUND -10C THROUGH THE DAY TUESDAY WHICH CREATES VERY LITTLE INSTABILITY OFF LAKE ERIE...AND ONLY MINOR LAKE INSTABILITY OFF LAKE ONTARIO. WHILE THERE WILL BE PLENTY OF MOISTURE IN THE LOWER LEVELS...DRIER AIR BEHIND AN UPPER LEVEL SHORTWAVE WILL LOWER THIS MOISTURE TO JUST BELOW THE SNOW CRYSTAL GROWTH ZONE...AND WITH WEAK UPWARD OMEGA FORCING THERE WILL NOT BE GOOD SNOW CRYSTAL GROWTH. WILL CONTINUE WITH LIKELY POPS ACROSS THE HIGHER TERRAIN SOUTH OF BUFFALO...AND CATEGORICAL POPS EAST OF LAKE ONTARIO WHERE LAKE ENHANCEMENT TO THE UPSLOPE SNOW SHOWERS SHOULD BRING SEVERAL INCHES DURING THE DAY TUESDAY. ANOTHER WEAK SHORTWAVE WILL CROSS WNY TUESDAY AND THIS WILL KEEP LOW CHANCE POPS FOR A SNOW SHOWER EVEN ACROSS THE LOWER ELEVATIONS. THIS SHORTWAVE WILL ALSO CAUSE LAKE ENHANCEMENT TO BE TRANSITORY THROUGH THE DAY. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR THIS SNOW EVENT FOR THE TUG HILL REGION CONTINUING INTO TUESDAY...AND TUESDAY NIGHT. HOWEVER WITH A CURRENT WINTER WEATHER ADVISORY ALREADY IN PLACE WILL JUST MENTION THE PROSPECTS FOR ADVISORY LEVEL SNOWS IN THE HWO. HIGHS ON TUESDAY WILL NOT CLIMB TOO MUCH FROM THEIR MORNING LOWS...WITH TEMPERATURES THROUGH THE DAY LARGELY IN THE LOW TO MID 30S. WINDS WILL CONTINUE TO BE GUSTY THROUGH THE MORNING HOURS BUT AS THE SURFACE LOW CARRIES FARTHER EASTWARD THROUGH ATLANTIC CANADA AND WINDS ALOFT WEAKEN THE GUSTY SURFACE WINDS SHOULD DIMINISH THROUGH THE DAY. TUESDAY NIGHT SOME DRIER AIR BEGINS TO FILTER ACROSS THE GREAT LAKES...YET THERE SHOULD STILL BE ENOUGH MOISTURE TO MAINTAIN THESE SNOW SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO. WITH THE FLOW VEERING A LITTLE THE SNOW SHOWERS ACROSS THE EASTERN LAKE ONTARIO REGION WILL BE MORE FOCUSED UPON OSWEGO AND SOUTHERN LEWIS COUNTIES. WEDNESDAY FURTHER DRYING ALOFT AND WARM AIR ADVECTION WILL BRING AN END TO THE WEAK LAKE ENHANCED SNOW SHOWERS EAST OF LAKE ONTARIO. EXPECT JUST A CHANCE FOR MORNING LAKE EFFECT SNOW...CARRYING NORTHWARD AND WEAKENING TO FLURRIES JUST SOUTH OF WATERTOWN. HIGH PRESSURE WILL CROSS OUR REGION...CENTERED TO OUR SOUTH...AND WITH THE AXIS OF A WEAK UPPER LEVEL RIDGE CROSSING THE EASTERN GREAT LAKES WE SHOULD SEE ADDITIONAL SUNSHINE THROUGH THE DAY. CLOUDS WILL BEGIN TO THICKEN FROM THE SOUTH WEDNESDAY AFTERNOON AND EVENING WELL AHEAD OF A STORM SYSTEM CROSSING THE SOUTHEAST. A PRIMARY SURFACE LOW WILL TRACK TO ABOUT WESTERN PENNSYLVANIA BEFORE AN UPPER LEVEL SHORTWAVE TROUGH TRANSFERS ENERGY TO A DEVELOPING COASTAL LOW THAT WILL QUICKLY DEEPEN. IT LOOKS LIKE THIS SYSTEM WILL MISS OUR AREA...WITH JUST A SLIGHT CHANCE THAT SOME LIGHT SNOW WILL BRUSH BY THE UPPER GENESEE RIVER VALLEY EARLY WEDNESDAY NIGHT. WITH THE WARM AIR ADVECTION ALOFT AND WINDS FROM THE SOUTHEAST HIGHS WEDNESDAY WILL CLIMB SEVERAL DEGREES WARMER THAN TUESDAY. HIGHS ON WEDNESDAY WILL CLIMB INTO THE MID AND UPPER 30S WITH A SPOT 40 POSSIBLE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... DURING THIS PERIOD...GFS/ECMWF FEATURE THE DEVELOPMENT OF A HIGH AMPLITUDE RIDGE OVER THE WESTERN UNITED STATES AND A LARGE BROAD TROUGH OVER THE EASTERN 2/3 OF THE U.S FROM THE COLORADO ROCKIES TO THE EASTERN SEA BOARD. INITIALLY...TEMPERATURES WILL START OUT SLIGHTLY ABOVE CLIMATOLOGY AND THEN ARE FORECAST TO GRADUALLY TREND COLDER THROUGH THE WEEKEND SATURDAY TO SUNDAY. A CLIPPER-TYPE LOW PRESSURE SYSTEM WILL SET THE STAGE...IT IS FORECAST TO TRACK JUST TO THE WEST OF THE REGION ACROSS THE UPPER GREAT LAKES. SOUTHERLY WINDS AHEAD OF THIS SYSTEM WILL PICK UP ACROSS THE REGION..THEN A COLD FRONT WILL CROSS WESTERN AND NORTH CENTRAL NEW YORK THURSDAY NIGHT INTO FRIDAY...BRINGING WITH IT A CHANCE OF RAIN AND SNOW SHOWERS. COLDER AIR FOLLOWING THIS SYSTEM WILL BRING A CHANCE FOR MORE SNOW SHOWERS AND POSSIBLE LAKE EFFECT SNOW FRIDAY NIGHT AND SATURDAY. HOWEVER...THERE ARE DIFFERENCES BETWEEN THE GFS/ECMWF WITH TIMING AND THE GENERAL STRENGTH OF THE CLIPPER-TYPE SYSTEM FORECAST TO MOVE ACROSS THE REGION. AT THIS POINT...IT SEEMS LIKELY THAT WESTERN/NORTH CENTRAL NY WILL SEE A GRADUAL RETURN TO COLDER TEMPERATURES OVER THE PERIOD. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... STEADIEST PRECIPITATION WILL LIFT ACROSS THE REGION FROM W-E THROUGH 15Z. EXPECT A COUPLE HOURS OF LIGHT RAIN AT MOST TAF SITES...WITH SOME -FZRA AT JHW/ART WHERE TEMPERATURES WILL BE A BIT COOLER. DOWNSLOPING SHOULD KEEP CIGS MVFR OR HIGHER AT MOST TAF LOCATIONS...BUT A PERIOD OF IFR OR LOWER CIGS IS LIKELY AT JHW WHICH DOES NOT DRY AS WELL IN THIS TYPE OF FLOW. PRECIPITATION WILL END LATE THIS MORNING...PROVIDING A BRIEF BREAK BEFORE THE NEXT ROUND OF SHOWERS MOVES IN THIS AFTERNOON. THERE STILL MAY BE LINGERING MOISTURE AND MVFR CIGS AHEAD OF THE COLD FRONT. SHOWERS WILL EVENTUALLY TRANSITION TO SNOW SHOWERS AS COLDER AIR WORKS IN. BESIDES THE RISK OF MIXED WINTRY PRECIPITATION...THERE WILL BE SOME LOW LEVEL WIND SHEAR TO CONTEND WITH THIS MORNING. WINDS AT 1500-2000 FT WILL AVERAGE 40-50 KTS WHILE SFC WINDS WILL BE IN THE VCNTY OF 10 KNOTS. BY THIS AFTERNOON...THE STRONGER WINDS ALOFT SHOULD BE AT LEAST PARTIALLY MIXING TO THE SFC. WIND GUSTS OVER 30 KTS WILL BE POSSIBLE AT KIAG AND KBUF LATER IN THE AFTERNOON. TONIGHT...MVFR CONDITIONS WILL BE LIKELY WITH VSBYS BEING LOWERED IN SNOW SHOWERS. THE MOST WIDESPREAD SNOWS WILL BE GENERATED EAST OF BOTH LAKES WHERE IFR CONDITIONS WILL BE POSSIBLE. OUTLOOK... TUESDAY...MVFR/IFR IN LIGHT SNOW SHOWERS. WEDNESDAY AND THURSDAY...MAINLY VFR. FRIDAY...MVFR/IFR WITH A CHANCE OF SNOW. && .MARINE... SOUTHERLY WINDS WILL BE GUSTY THIS MORNING...ESPECIALLY ON LAKE ERIE...AS STRONG WINDS ALOFT OCCASIONALLY MIX DOWN. AFTER THIS...EXPECT A BIT OF LULL...BEFORE A COLD FRONT CROSSES THE WATERS AROUND MIDDAY. THIS WILL SHIFT WINDS TO THE SOUTHWEST AND CAUSE AN INCREASE TO 35 KNOT GALES BEHIND THE FRONT. EXPECT GALES TO CONTINUE THROUGH TONIGHT...GRADUALLY SUBSIDING FROM WEST TO EAST ON TUESDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY...WITH NO HEADLINES ANTICIPATED. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR NYZ004- 005-012>014-019>021-085. WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR NYZ001>003-010>012-019-085. WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ007-008. FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ006. WIND ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST TUESDAY FOR NYZ004-013-014-020-021. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR LEZ040- 041. GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST TUESDAY FOR LEZ020-040-041. GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST TUESDAY FOR LOZ042-043-062-063. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LOZ045. GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST TUESDAY FOR LOZ044-045-064-065. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...THOMAS LONG TERM...AR AVIATION...APFFEL MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
425 AM EST MON FEB 11 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE INTO SOUTHERN QUEBEC TODAY. THIS WILL BRING A PERIOD OF RAIN EARLY TODAY...WITH SOME FREEZING RAIN ACROSS THE INTERIOR VALLEYS AND A WINTRY MIX EAST OF LAKE ONTARIO. AFTER THIS WINDS WILL INCREASE BEHIND AN ASSOCIATED COLD FRONT...CAUSING RAIN SHOWERS TO CHANGE TO SNOW LATER TODAY AND TONIGHT. && .NEAR TERM /THROUGH TONIGHT/... THERE WILL BE SEVERAL TRANSITIONS TODAY...AS A SERIES OF BOUNDARIES ASSOCIATED WITH LOW PRESSURE ACROSS THE UPPER LAKES WILL INFLUENCE OUR WEATHER. THROUGH THIS MORNING...THE MAIN SOURCE OF LIFT WILL COME FROM AN AREA OF WARM AIR ADVECTION ALOFT. RADAR TRENDS SUGGEST STEADIEST RAINS WILL FOCUS NORTH OF A BUFFALO TO ROCHESTER LINE...WITH LIGHTER QPFS ACROSS THE SOUTHERN TIER. FORTUNATELY...TEMPERATURES SHOULD REMAIN JUST ABOVE FREEZING IN THESE LOCATIONS...WITH DOWNSLOPING OFFSETTING EVAPORATIONAL COOLING. A FREEZING RAIN ADVISORY REMAINS IN EFFECT ACROSS THE INTERIOR...WHERE TEMPERATURES AT 400 AM ARE IN THE LOWER TO MID 30S. HOWEVER...WITH RAIN MOVING IN AND DEW POINTS IN THE 20S...EXPECT TEMPERATURES TO DROP A FEW DEGREES AS RAIN STARTS. RADAR TRENDS ARE WELL CAPTURED BY THE HRRR (THE NAM/GFS/RGEM ARE TOO HIGH FOR QPF ACROSS THE INTERIOR). FOLLOWING THIS...EXPECT SOME LIGHT (A FEW HUNDREDTHS OF AN INCH) QPF HOWEVER THIS WILL FALL AS FREEZING RAIN IN MANY SPOTS...SO WILL KEEP THE ADVISORY UP. STEADIER PRECIPITATION WILL MOVE EAST OF LAKE ONTARIO THROUGH DAYBREAK...BRINGING THE GREATEST ICING POTENTIAL FOR THIS EVENT. THERE WILL BE MODEST DOWNSLOPE WARMING HERE TOO...BUT WITH DRY AND COOLER AIR IN PLACE EXPECT AROUND A TENTH OF AN INCH OF FREEZING RAIN GLAZE...WITH PERHAPS SOME LIGHT SNOW OR SLEET ACCUMULATION. ALL OF THIS PRECIPITATION SHOULD LIFT FROM SW-NE...ENDING ACROSS WESTERN PORTIONS AROUND DAYBREAK...AND LATE THIS MORNING EAST OF LAKE ONTARIO. THIS SHOULD PROVIDE A BRIEF LULL IN THE ACTION UNTIL THE NEXT BOUNDARY CROSSES. THE NEXT PHASE OF THIS EVENT WILL COME AS THE COLD FRONT ASSOCIATED WITH THE LOW MOVES ACROSS THE REGION. IT WILL ENTER WESTERN NEW YORK AROUND NOON...SWEEPING TO EAST OF LAKE ONTARIO AROUND SUNSET. THIS WILL BRING MAINLY SCATTERED RAIN SHOWERS...BUT ITS MORE SIGNIFICANT IMPACT WILL BE AN INCREASE IN WINDS BEHIND IT. GUSTY SOUTHWESTERLY WINDS WILL PICK UP FIRST ACROSS THE NIAGARA FRONTIER...SPREADING TO THE EAST LATE AFTERNOON AND EVENING. THE LOW IS NOT PARTICULARLY DEEP...NOR IS THE COLD ADVECTION TOO STRONG. WITH ONLY MODEST PRESSURE RISES DONT EXPECT EXTREMELY DEEP MIXING TO TAP THE 50 KNOTS ALOFT...BUT STILL SUFFICIENT TO BRING ADVISORY CRITERIA GUSTS OF 45 TO 50 MPH LATER IN THE AFTERNOON. THE 230-240 DEGREE WIND DIRECTION FAVORS THE STRONGER WINDS FROM THE LAKE ERIE SHORE ACROSS THE NIAGARA FRONTIER TO ROCHESTER. LATER IN THE EVENING WINDS BECOME MORE WESTERLY...WHICH WILL SPREAD STRONGER WINDS INTO THE INTERIOR SOUTHERN TIER AND WESTERN FINGER LAKES. A WIND ADVISORY REMAINS IN EFFECT ACROSS ALL BUT THE EASTERN LAKE ONTARIO REGION. BEHIND THE COLD FRONT...THE UPPER LEVEL TROF ASSOCIATED WITH THE LOW WILL MOVE ACROSS THE REGION. THIS WILL USHER IN COLDER AIR BOTH ALOFT AND AT THE SURFACE. ITS IMPORTANT TO NOTE THAT THIS IS NOT A VERY COLD AIR MASS...WITH 850 MB TEMPERATURES LIKELY TO DROP TO AROUND -10C TONIGHT. THIS IS NOT REALLY COLD ENOUGH FOR PURE LAKE EFFECT...BUT WITH SIGNIFICANT MOISTURE ASSOCIATED WITH THE UPPER TROF...AND SOME UPSLOPE ENHANCEMENT...EXPECT THERE WILL BE SOME SNOW EAST AND NORTHEAST OF THE LAKES TONIGHT. GIVEN THE MINIMAL CONTRIBUTION FROM LAKE INSTABILITY...EXPECT QPFS ARE A BIT OVERDONE BY THE NAM/RGEM WITH THE UPSLOPE...BUT DO FEEL SOME PRECIPITATION IS CERTAINLY REASONABLE. SNOW RATIOS SHOULD NOT BE GREAT GIVEN THE MARGINALLY COLD AIR...WITH 2 OR 3 INCHES SNOW ACCUMULATION LIKELY ON THE TUG HILL TONIGHT...AND A BIT LESS ON THE CHAUTAUQUA RIDGE. IF THERE WERE NOT ALREADY ADVISORIES IN PLACE...THIS PORTION OF THE EVENT COULD REQUIRE A SNOW ADVISORY...BUT WITH A BREAK BETWEEN THE TWO WILL HANDLE THIS AS TWO EVENTS RATHER THAN COMPLICATING THE ISSUE. THIS IS A CHALLENGING EVENT...BECAUSE IF MODEL QPF DOES VERIFY OR IF SNOW RATIONS EXCEED 20 TO 1...THEN THIS COULD ACTUALLY APPROACH WARNING CRITERIA ON THE TUG HILL. AT THIS TIME...NEITHER OF THESE SCENARIOS APPEAR LIKELY. SNOWS WILL BE LESS OFF LAKE ERIE...BUT THE SW FLOW MAY BRING AN INCH OR SO ACROSS THE BUFFALO METRO AREA...WITH LOCALLY HIGHER AMOUNTS ACROSS THE BOSTON HILLS AND CHAUTAUQUA RIDGE. OTHERWISE...TEMPERATURES WILL WARM BRIEFLY TODAY...ESPECIALLY IN THE FINGER LAKES REGION...WITH HIGHS IN THE 40S AHEAD OF THE FRONT. WINDS WILL BE GUSTY FOR A FEW HOURS THROUGH DAYBREAK ALONG I-90 FROM THE NY/PA LINE TO BUFFALO AS DOWNSLOPING RESULTS IN GUSTS UP TO 40 MPH. 925 MB WINDS WILL DIMINISH AFTER 12Z...DIMINISHING WINDS HERE UNTIL THE FRONT MOVES THROUGH. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... ON TUESDAY A SURFACE COLD FRONT WILL BE WELL TO THE EAST WITH COLD AIR ADVECTING ACROSS THE EASTERN GREAT LAKES. THIS WILL BE A MARGINAL SET UP FOR LAKE EFFECT SNOW...WITH THE MAIN FORCING MECHANISM BEING MORE THE UPSLOPE FLOW OVER HIGHER TERRAIN EAST OF BOTH GREAT LAKES. TEMPERATURES AT 850 HPA WILL DROP TO AROUND -10C THROUGH THE DAY TUESDAY WHICH CREATES VERY LITTLE INSTABILITY OFF LAKE ERIE...AND ONLY MINOR LAKE INSTABILITY OFF LAKE ONTARIO. WHILE THERE WILL BE PLENTY OF MOISTURE IN THE LOWER LEVELS...DRIER AIR BEHIND AN UPPER LEVEL SHORTWAVE WILL LOWER THIS MOISTURE TO JUST BELOW THE SNOW CRYSTAL GROWTH ZONE...AND WITH WEAK UPWARD OMEGA FORCING THERE WILL NOT BE GOOD SNOW CRYSTAL GROWTH. WILL CONTINUE WITH LIKELY POPS ACROSS THE HIGHER TERRAIN SOUTH OF BUFFALO...AND CATEGORICAL POPS EAST OF LAKE ONTARIO WHERE LAKE ENHANCEMENT TO THE UPSLOPE SNOW SHOWERS SHOULD BRING SEVERAL INCHES DURING THE DAY TUESDAY. ANOTHER WEAK SHORTWAVE WILL CROSS WNY TUESDAY AND THIS WILL KEEP LOW CHANCE POPS FOR A SNOW SHOWER EVEN ACROSS THE LOWER ELEVATIONS. THIS SHORTWAVE WILL ALSO CAUSE LAKE ENHANCEMENT TO BE TRANSITORY THROUGH THE DAY. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR THIS SNOW EVENT FOR THE TUG HILL REGION CONTINUING INTO TUESDAY...AND TUESDAY NIGHT. HOWEVER WITH A CURRENT WINTER WEATHER ADVISORY ALREADY IN PLACE WILL JUST MENTION THE PROSPECTS FOR ADVISORY LEVEL SNOWS IN THE HWO. HIGHS ON TUESDAY WILL NOT CLIMB TOO MUCH FROM THEIR MORNING LOWS...WITH TEMPERATURES THROUGH THE DAY LARGELY IN THE LOW TO MID 30S. WINDS WILL CONTINUE TO BE GUSTY THROUGH THE MORNING HOURS BUT AS THE SURFACE LOW CARRIES FARTHER EASTWARD THROUGH ATLANTIC CANADA AND WINDS ALOFT WEAKEN THE GUSTY SURFACE WINDS SHOULD DIMINISH THROUGH THE DAY. TUESDAY NIGHT SOME DRIER AIR BEGINS TO FILTER ACROSS THE GREAT LAKES...YET THERE SHOULD STILL BE ENOUGH MOISTURE TO MAINTAIN THESE SNOW SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO. WITH THE FLOW VEERING A LITTLE THE SNOW SHOWERS ACROSS THE EASTERN LAKE ONTARIO REGION WILL BE MORE FOCUSED UPON OSWEGO AND SOUTHERN LEWIS COUNTIES. WEDNESDAY FURTHER DRYING ALOFT AND WARM AIR ADVECTION WILL BRING AN END TO THE WEAK LAKE ENHANCED SNOW SHOWERS EAST OF LAKE ONTARIO. EXPECT JUST A CHANCE FOR MORNING LAKE EFFECT SNOW...CARRYING NORTHWARD AND WEAKENING TO FLURRIES JUST SOUTH OF WATERTOWN. HIGH PRESSURE WILL CROSS OUR REGION...CENTERED TO OUR SOUTH...AND WITH THE AXIS OF A WEAK UPPER LEVEL RIDGE CROSSING THE EASTERN GREAT LAKES WE SHOULD SEE ADDITIONAL SUNSHINE THROUGH THE DAY. CLOUDS WILL BEGIN TO THICKEN FROM THE SOUTH WEDNESDAY AFTERNOON AND EVENING WELL AHEAD OF A STORM SYSTEM CROSSING THE SOUTHEAST. A PRIMARY SURFACE LOW WILL TRACK TO ABOUT WESTERN PENNSYLVANIA BEFORE AN UPPER LEVEL SHORTWAVE TROUGH TRANSFERS ENERGY TO A DEVELOPING COASTAL LOW THAT WILL QUICKLY DEEPEN. IT LOOKS LIKE THIS SYSTEM WILL MISS OUR AREA...WITH JUST A SLIGHT CHANCE THAT SOME LIGHT SNOW WILL BRUSH BY THE UPPER GENESEE RIVER VALLEY EARLY WEDNESDAY NIGHT. WITH THE WARM AIR ADVECTION ALOFT AND WINDS FROM THE SOUTHEAST HIGHS WEDNESDAY WILL CLIMB SEVERAL DEGREES WARMER THAN TUESDAY. HIGHS ON WEDNESDAY WILL CLIMB INTO THE MID AND UPPER 30S WITH A SPOT 40 POSSIBLE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... DURING THIS PERIOD...GFS/ECMWF FEATURE THE DEVELOPMENT OF A HIGH AMPLITUDE RIDGE OVER THE WESTERN UNITED STATES AND A LARGE BROAD TROUGH OVER THE EASTERN 2/3 OF THE U.S FROM THE COLORADO ROCKIES TO THE EASTERN SEA BOARD. INITIALLY...TEMPERATURES WILL START OUT SLIGHTLY ABOVE CLIMATOLOGY AND THEN ARE FORECAST TO GRADUALLY TREND COLDER THROUGH THE WEEKEND SATURDAY TO SUNDAY. A CLIPPER-TYPE LOW PRESSURE SYSTEM WILL SET THE STAGE...IT IS FORECAST TO TRACK JUST TO THE WEST OF THE REGION ACROSS THE UPPER GREAT LAKES. SOUTHERLY WINDS AHEAD OF THIS SYSTEM WILL PICK UP ACROSS THE REGION..THEN A COLD FRONT WILL CROSS WESTERN AND NORTH CENTRAL NEW YORK THURSDAY NIGHT INTO FRIDAY...BRINGING WITH IT A CHANCE OF RAIN AND SNOW SHOWERS. COLDER AIR FOLLOWING THIS SYSTEM WILL BRING A CHANCE FOR MORE SNOW SHOWERS AND POSSIBLE LAKE EFFECT SNOW FRIDAY NIGHT AND SATURDAY. HOWEVER...THERE ARE DIFFERENCES BETWEEN THE GFS/ECMWF WITH TIMING AND THE GENERAL STRENGTH OF THE CLIPPER-TYPE SYSTEM FORECAST TO MOVE ACROSS THE REGION. AT THIS POINT...IT SEEMS LIKELY THAT WESTERN/NORTH CENTRAL NY WILL SEE A GRADUAL RETURN TO COLDER TEMPERATURES OVER THE PERIOD. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... WHILE VFR CONDITIONS WILL BE IN PLACE FOR THE BULK OF THE REGION FOR THE REST OF THE OVERNIGHT...AN AREA OF RAIN OVER LAKE ERIE AND NORTHWEST PENNSYLVANIA WILL LIFT ACROSS OUR REGION DURING THE OVERNIGHT HOURS. THIS PRECIPITATION SHOULD BE IN THE FORM OF RAIN AT THE MAJOR TAF SITES ACROSS WESTERN NEW YORK (KBUF/KROC)...BUT THERE IS A SLIGHT CHANCE THAT IT COULD FALL AS A BRIEF PERIOD OF -FZRA AT KJHW. OTHERWISE...CIGS SHOULD DETERIORATE TO AT LEAST MVFR ACROSS PARTS OF THE SRN TIER. AS THE PCPN PUSHES FURTHER EAST BY DAYBREAK...A WINTRY MIX OF FREEZING RAIN...SLEET AND EVEN SNOW WILL BE POSSIBLE AT KART. ON MONDAY...THE PCPN WILL END FROM WEST TO EAST IN THE FORM OF JUST RAIN...WITH AN ENDING TIME OF 12-14Z OVER THE WESTERN COUNTIES AND 16Z EAST OF LK ONTARIO. CIGS WILL LIKELY DROP TO MVFR FOR A FEW HOURS IN THE WAKE OF THE STEADIER PCPN...WITH SOME IFR CIGS POSSIBLE AT KJHW AND KELZ. THESE CIGS SHOULD GENERALLY IMPROVE DURING THEM MIDDAY AND AFTERNOON. BESIDES THE RISK OF MIXED WINTRY PRECIPITATION...THERE WILL BE SOME LOW LEVEL WIND SHEAR TO CONTEND WITH TONIGHT AND FOR AT LEAST THE MORNING HOURS OF MONDAY. WINDS AT 1500-2000 FT WILL AVERAGE 40-50 KTS WHILE SFC WINDS WILL BE IN THE VCNTY OF 10 KNOTS. BY MONDAY AFTERNOON...THE STRONGER WINDS ALOFT SHOULD BE AT LEAST PARTIALLY MIXING TO THE SFC. WIND GUSTS OVER 30KTS WILL BE POSSIBLE AT KIAG AND KBUF LATER IN THE AFTERNOON. ON MONDAY NIGHT...MVFR CONDITIONS WILL BE LIKELY WITH VSBYS BEING LOWERED IN SNOW SHOWERS. THE MOST WIDESPREAD SNOWS WILL BE GENERATED EAST OF BOTH LAKES WHERE IFR CONDITIONS WILL BE POSSIBLE. OUTLOOK... TUESDAY...MVFR/IFR IN LIGHT SNOW SHOWERS. WEDNESDAY AND THURSDAY...MAINLY VFR. FRIDAY...MVFR/IFR WITH A CHANCE OF SNOW. && .MARINE... SOUTHERLY WINDS WILL BE GUSTY THIS MORNING...ESPECIALLY ON LAKE ERIE...AS STRONG WINDS ALOFT OCCASIONALLY MIX DOWN. AFTER THIS...EXPECT A BIT OF LULL...BEFORE A COLD FRONT CROSSES THE WATERS AROUND MIDDAY. THIS WILL SHIFT WINDS TO THE SOUTHWEST AND CAUSE AN INCREASE TO 35 KNOT GALES BEHIND THE FRONT. EXPECT GALES TO CONTINUE THROUGH TONIGHT...GRADUALLY SUBSIDING FROM WEST TO EAST ON TUESDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY...WITH NO HEADLINES ANTICIPATED. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR NYZ004- 005-012>014-019>021-085. WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR NYZ001>003-010>012-019-085. WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ007-008. FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ006. WIND ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST TUESDAY FOR NYZ004-013-014-020-021. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR LEZ040- 041. GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST TUESDAY FOR LEZ020-040-041. GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST TUESDAY FOR LOZ042-043-062-063. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LOZ045. GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST TUESDAY FOR LOZ044-045-064-065. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...THOMAS LONG TERM...AR AVIATION...RSH MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
359 AM EST MON FEB 11 2013 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH THROUGH THE AREA THIS MORNING AS A COLD FRONT PUSHES EAST THROUGH THE AREA AND OFFSHORE BY TONIGHT. A LOW PRESSURE AREA WILL MOVE NORTHEAST ALONG THE COAST WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR THURSDAY AND FRIDAY. ANOTHER COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY NIGHT. && .NEAR TERM /TODAY/... AS OF 350 AM MONDAY...ONLY SOME VERY LIGHT PRECIPITATION IS REACHING THE GROUND OVER THE MHX CWA. THE LATEST RAP MODEL STILL SHOWS PRECIPITATION BECOMING MORE WIDESPREAD AFTER 12Z AND WILL CONTINUE TO RAMP UP POPS THROUGH THE EARLY MORNING HOURS...BECOMING CATEGORICAL AFTER 12Z. WARM FRONT CONTINUE TO MOVE NORTH THROUGH THE CWA WITH MOST TEMPERATURES NOW IN THE LOWER TO MIDDLE 50S WITH 62 DEGREES AT CAPE HATTERAS. WITH A FAIRLY DEEP SOUTHERLY FLOW...EXPECT TEMPERATURES TO RISE INTO THE MIDDLE AND UPPER 60S OVER MOST AREAS WITH A FEW SPOTS OVER THE SOUTHERN COUNTIES PERHAPS TOUCHING 70 DEGREES. THINK MOST OF THE WIDESPREAD PRECIPITATION WILL OCCUR BEFORE 18Z...WITH RAIN BECOMING MORE SCATTERED AFTER 18Z. LATEST NAM12 AND GFS SHOW A RIBBON OF INSTABILITY POSITIONING ITSELF JUST OFFSHORE BY LATER TODAY AND HAVE INCLUDED A SLIGHT CHANCE OF THUNDER FOR THE COASTAL WATERS. && .SHORT TERM /TONIGHT/... AS OF 355 AM MONDAY...PRECIPITATION WILL TAPER FROM NORTH TO SOUTH TONIGHT WITH MINIMAL RAIN CHANCES EXPECTED AFTER MIDNIGHT AS DRIER AIR FILTERS INTO THE REGION FROM THE NORTH. CLOUDINESS WILL LIKEWISE DECREASE AS WE HEAD TOWARD THE MORNING HOURS. MINIMUM TEMPERATURES ACROSS THE AREA WILL RANGE FROM 45 TO 50 DEGREES. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 340 AM MON...UPPER LEVEL TROUGH OVER THE EASTERN GREAT LAKES WILL CONTINUE TO PUSH NE INTO QUEBEC ON TUES WHILE BROAD AND WEAK UPPER RIDGING ESTABLISHES ITSELF ACROSS FL/GULF OF MEXICO. THESE FEATURES WILL PRODUCE WESTERLY FLOW ALOFT. SURFACE HIGH PRESSURE NORTH OF THE AREA WILL MOVE INTO THE REGION TUES BRINGING WARM TEMPS INTO EASTERN NC...WITH HIGHS IN THE LOW/MID 60S. MONDAY`S COLD FRONT WILL REMAIN STALLED OFF THE SE COAST WITH AN AREA OF LOW PRESSURE FORMING ALONG THE BOUNDARY OVER THE SE STATES TUES NIGHT INTO WED MORNING. GREATER DIFFERENCES EXIST BETWEEN THE 00Z RUNS OF THE GFS AND ECMWF WITH THE SURFACE LOW TRACK FARTHER INLAND WITH THE GFS SCENARIO WHILE THE ECMWF LOW TRACKS ALONG THE COAST...SIMILAR TO PREVIOUS RUNS. THE GFS IS ALSO STRONGER WITH THE MIDLEVEL SHORTWAVE DIGGING SOUTHEAST ACROSS THE SOUTHERN STATES. HEDGED SLIGHTLY CLOSER TO THE GFS GIVEN ITS OPERATIONAL SUPPORT WITH THE GFS ENSEMBLE. THIS WILL MEAN SLIGHTLY MORE QPF BUT A CONTINUATION OF HIGH POPS TO CATEGORICAL BY WED ACROSS SOUTHERN HALF OF THE CWA. EXPECT PRECIP TO END FROM WEST TO EAST LATE WED NIGHT AS THE SURFACE LOW PUSHES NE INTO THE NORTHERN ATLANTIC OCEAN. STRONG SHORTWAVE ALOFT WILL ALSO PUSH THROUGH THE REGION WED NIGHT...WITH RIDGING SURFACE AND ALOFT BUILDING INTO EASTERN NC THURS. THE HIGH WILL PUSH OFFSHORE FRI. TEMPS WILL BE NEAR CLIMO THURS AND FRI. BY EARLY WEEKEND IT APPEARS MORE LIKELY THAT AN ARCTIC AIRMASS WILL INVADE THE EASTERN CONUS AS BOTH GFS/ECMWF INDICATE DEEP TROUGHING ALOFT...AND CONTINUED TO HEDGE CLOSER TO THE ECMWF FOR LATE IN THE EXTENDED. THERE COULD BE SOME SHOWERS SAT AHEAD OF THE ARCTIC COLD FRONT...AND WILL MAINTAIN SLIGHT CHANCE POPS. SUN WILL BE QUITE A BIT COLDER WITH HIGHS IN THE LOW/MID 40S. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... SHORT TERM /THROUGH MONDAY/... AS OF 1245 AM MONDAY...ONLY MADE MINOR TIMING ADJUSTMENTS FOR THE LATEST TAF CYCLE. LOW-LEVEL MOISTURE WILL CONTINUE TO PUSH INTO EASTERN NORTH CAROLINA AS A WARM FRONT LIFTS TO THE NORTH THIS MORNING. PER LATEST 4 KM WRF AND RAP MODELS...LIGHT RAIN SHOULD BECOME WIDESPREAD BY AROUND 12Z. AS A COLD FRONT THEN MOVES ACROSS THE AREA...RAIN WILL PERSIST INTO THE EVENING BEFORE THE FRONT SHIFTS OFFSHORE. A STRONG LLJ WILL DEVELOP...SO EXPECT GUSTY WINDS TO INCREASE MONDAY MORNING THROUGH THE AFTERNOON. CROSSWINDS WILL BE AN ISSUE FOR SITES USING A E-W OR NW-SE ORIENTED RUNWAY. RAINS WILL CONTINUE ALL DAY WITH CEILINGS FLIRTING NEAR OR JUST BELOW IFR. LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... AS OF 340 AM MON...EXPECT PREDOMINANT VFR CONDITIONS TUES AS HIGH PRESSURE BUILDS SOUTH OVER THE TERMINALS. SUB-VFR EXPECTED LATE TUES NIGHT AS AN AREA OF LOW PRESSURE DEVELOPS TO THE SW AND MOVES NE OVER EASTERN NC. ADDITIONAL PRECIP WITH LOWERED CEILINGS AND VSBYS POSSIBLE ON WED. RETURN TO VFR EXPECTED THURS AS HIGH PRESSURE BUILDS ACROSS EASTERN NC. && .MARINE... SHORT TERM /THROUGH MONDAY/... AS OF 355 AM MONDAY...AS WARM FRONT LIFTS NORTH OF THE REGION...GUSTY SOUTH TO SOUTHWEST WINDS WILL DEVELOP THIS MORNING WITH 20 TO 25 KNOT SPEEDS LIKELY BY AROUND MID-MORNING. PER LATEST LOCAL NWPS MODEL...WILL SEE SEAS INCREASE TO AS HIGH AS 11 FEET OVER SOME OF THE CENTRAL AND NORTHERN WATERS TODAY INTO TONIGHT. THE WINDS WILL BECOME MORE W/WNW BEHIND THE FRONT AS IT MOVES OFFSHORE LATER TONIGHT AND SHOULD GRADUALLY SUBSIDE TOWARD MORNING. GIVEN GOOD CONSISTENCY IN MODEL WIND FIELDS...NO CHANGES HAVE BEEN MADE TO CURRENT SMALL CRAFT ADVISORIES. LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 345 AM MON...HIGH PRESSURE BUILDS IN FOR TUES BRINGING GOOD BOATING CONDITIONS. WEAK LOW PRES WILL DEVELOP DURING THE DAY WED SW OF THE NC COASTAL WATERS. THIS WILL BRING EASTERLY WINDS TO START ACROSS THE AREA. CONDITIONS LOOK TO REMAIN SUB SCA HOWEVER ON WED. DURING THE AFTERNOON WED...AS THE LOW PULLS EASTWARD... WINDS WILL SWITCH TO THE WEST AND THEN NORTHWEST BY EVENING. EXPECT A BRIEF PERIOD OF 15-25 KT WINDS AND SEAS 6-8 FT WED NIGHT INTO EARLY THUR. HIGH PRESSURE WILL BE IN CONTROL FOR THE REMAINDER OF THE WEEK BRINGING GOOD BOATING CONDITIONS. LOCAL SWAN/NWPS IN GOOD SHAPE THROUGH THURS THEN BLENDED PREVIOUS SEAS FORECAST WITH LATEST WAVEWATCH III GUIDANCE THURS NIGHT AND FRI WITH NO MAJOR CHANGES. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 10 PM EST THIS EVENING FOR AMZ135. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS EVENING FOR AMZ130. SMALL CRAFT ADVISORY UNTIL 10 AM EST TUESDAY FOR AMZ152-154. SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ156-158. SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR AMZ150. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...DAG AVIATION...CTC/DAG MARINE...CTC/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1248 AM EST MON FEB 11 2013 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE MOVING OFFSHORE TONIGHT AND A WARM FRONT WILL LIFT NORTH THROUGH THE AREA LATE TONIGHT. A COLD FRONT WILL SLOWLY MOVE THROUGH THE AREA MONDAY AND PUSH OFFSHORE MONDAY NIGHT...STALLING JUST SOUTH OF THE AREA TUESDAY. A LOW PRESSURE AREA WILL MOVE NORTHEAST ALONG THE COAST WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR THURSDAY AND FRIDAY. A COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY NIGHT. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1240 AM MONDAY...WARM FRONT LIES JUST OFF OUR SOUTHERN COAST AS OF 05Z WITH TEMPERATURES IN THE 60S AT FRYING PAN BUOY AND AT THE BUOY 30 MILES SOUTHEAST OF NEW RIVER. MEANWHILE...TEMPERATURES GENERALLY IN THE MIDDLE 40S TO AROUND 50 OVER LAND AREAS. THE WARM FRONT WILL PIVOT TO THE NORTH OF THE REGION WITH TEMPERATURES SLOWLY RISING THROUGH THE EARLY MORNING HOURS. THE LEADING EDGE OF THE RAIN SHIELD IS JUST NOW REACHING OUR FAR WESTERN COUNTIES. PER LATEST 4 KM WRF AND RAP MODELS...THE PRECIPITATION SHOULD BECOME MORE WIDESPREAD AFTER ABOUT 11Z OR 12Z. CURRENT FORECAST ON TRACK WITH POPS RAMPING UP TOWARD MORNING. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... AS OF 300 PM SUNDAY...PER NEAR TERM...MODELS REMAIN IN DECENT AGREEMENT FOR PERIOD...AND NO SIGNIFICANT CHANGES TO PREVIOUS FCST. STRONG WAA EXPECTED TO PRODUCE WDSPRD PCPN EVENT...BUT ENOUGH MODEL DIFFERENCES ON QPF TO LIMIT CONFIDENCE IN GOING WITH 100% POPS. ALSO WILL NOT INTRODUCE MENTION OF TSTMS AS LACK OF INSTABILITY EXPECTED TO LIMIT CONVECTION. EVEN WITH CLOUDS AND PCPN...STRONG S-SW FLOW WILL ALLOW MAX TEMPS TO REACH INTO MID-UPR 60S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AS OF 330 PM SUN...MEDIUM TO LONG TERM PERIOD WILL CONTINUE TO FAVOR MORE CONSISTENT ECMWF. THE PERIOD WILL START OUT DRY WITH HIGH PRESSURE FOR TUESDAY...FOLLOWED BY INCREASING RAIN CHANCES LATE TUE NIGHT AND CONTINUING THROUGH WED...THEN A DRY PERIOD FOR THE END OF THE WEEK. SHARPLY COLDER TEMPS EXPECTED FOR THE SECOND HALF OF THE WEEKEND. FOR MON NIGHT...SOME LINGERING SHOWERS WILL ACCOMPANY COOL FRONT DROPPING SOUTH THROUGH EASTERN NC...ESP FOR THE SOUTHERN HALF OF THE FA. HAVE RAISED POPS A BIT HERE ACCORDINGLY TO FALL MORE IN LINE WITH ECM MOS. VERY DRY HIGH PRES WILL MOVE INTO THE REGION TUE. THE DRYING WILL BE AIDED BY COMPRESSIONAL 850MB WNW FLOW OFF THE SRN APPALACHIANS. THIS WILL ALSO BRING WARM TEMPS INTO E NC...WITH HIGHS IN THE LOW TO MID 60S. THE LIMITING FACTOR FOR SERIOUS FIRE WEATHER CONCERNS WILL BE THE LIGHT SFC WINDS...ONLY ON ORDER OF 5 TO 10 KT. BOUNDARY LAYER WILL BE QUITE DRY TO START TUE NIGHT...THOUGH BY LATE NIGHT THE AREA WILL BE UNDER THE NOSE OF A FAIRLY STRONG SWLY LLJ. ISENTROPIC LIFT WILL INCREASE QUITE DRASTICALLY AFTER AROUND 06Z... AND INHERITED LIKELY POPS STILL LOOK GOOD FOR SOUTHERN TWO THIRDS OF THE FA. WEAK SFC CYCLOGENESIS OCCURS DURING THE DAY WED ACROSS SRN COASTAL WATERS...KEEPING THE FCST AREA IN THE COOL SECTOR. HAVE BROUGHT TEMPS DOWN 5 TO 7 DEGREES FOR HIGHS WED DUE TO LOW LEVEL NNE FLOW AND PLENTIFUL LOW CLOUDS AND LIGHT PRECIP. ECM MOS WAS PREFERRED OVER GFS MOS...AS GFS WAS ON THE WARM SIDE WITH SFC LOW A BIT FURTHER NORTH. LOOKS TO BE A HIGH POP/LOW QPF EVENT WITH WEAK UPR LEVEL SUPPORT...AND MUCH OF THE LIFT WILL BE CONFINED BELOW 700MB. ORGANIZED SHOWERS MOVE EAST WED EVENING WITH DEPARTING SFC LOW... THOUGH COULD SEE SOME REMAINING ISOLATED SHOWERS AS MID LEVEL SHORTWAVE SWINGS THROUGH. HIGH PRES WILL BUILD IN FOR THUR AND FRI BRINGING DRY CONDITIONS AND NEAR NORMAL TEMPS. LOOKING AHEAD TO THE WEEKEND...IT IS LOOKING MORE LIKELY THAT AN ARCTIC AIRMASS WILL INVADE THE EASTERN CONUS AS BOTH GFS/EMWF AND THEIR ENSEMBLE MEAN HEIGHT FIELDS INDICATE DEEP TROUGHING IN THE EAST. SIDED WITH THE ECMWF FOR TIMING...AS GFS IS ABOUT 24 FASTER. THE ECM HAS SUPPORT FROM ITS ENSEMBLE MEAN HEIGHT FIELDS WHICH HAS BETTER CLUSTERING BEYOND THE 156 HOUR TIME FRAME. THERE COULD BE SOME SHOWERS SATURDAY AHEAD OF THE ARCTIC COLD FRONT...THOUGH THIS FAR OUT WILL NOT INTRODUCE HIGHER THAN SLIGHT CHANCE POPS. SUNDAY WILL BE QUITE A BIT COLDER WITH HIGH STRUGGLING INTO THE 40S. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... SHORT TERM /THROUGH MONDAY/... AS OF 1245 AM MONDAY...ONLY MADE MINOR TIMING ADJUSTMENTS FOR THE LATEST TAF CYCLE. LOW-LEVEL MOISTURE WILL CONTINUE TO PUSH INTO EASTERN NORTH CAROLINA AS A WARM FRONT LIFTS TO THE NORTH THIS MORNING. PER LATEST 4 KM WRF AND RAP MODELS...LIGHT RAIN SHOULD BECOME WIDESPREAD BY AROUND 12Z. AS A COLD FRONT THEN MOVES ACROSS THE AREA...RAIN WILL PERSIST INTO THE EVENING BEFORE THE FRONT SHIFTS OFFSHORE. A STRONG LLJ WILL DEVELOP...SO EXPECT GUSTY WINDS TO INCREASE MONDAY MORNING THROUGH THE AFTERNOON. CROSSWINDS WILL BE AN ISSUE FOR SITES USING A E-W OR NW-SE ORIENTED RUNWAY. RAINS WILL CONTINUE ALL DAY WITH CEILINGS FLIRTING NEAR OR JUST BELOW IFR. LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... AS OF 330 PM SUN...COULD BE SOME LINGERING SHOWERS MAINLY AT KEWN AND KOAJ MON NIGHT BEFORE HIGH PRES MOVES IN LATE NIGHT INTO TUESDAY. MORE RAIN MOVES IN LATE TUE NIGHT AND LINGERS THROUGH WED. THERE COULD BE SUB VFR CIGS WITH THE SHOWERS. HIGH PRES BUILDS FOR THUR AND FRI. && .MARINE... SHORT TERM /THROUGH MONDAY/... AS OF 1245 AM MONDAY...LIGHT ESE/SE WINDS WILL BECOME MORE SOUTHERLY AND INCREASE OVER THE NEXT FEW HOURS AS A WARM FRONT LIFTS NORTH OF THE REGION. SMALL CRAFT CONDITIONS SHOULD DEVELOP TOWARD MORNING AS LATEST 10M WIND FORECASTS FOR THE HIGH-RES WRF AND RAP MODELS INDICATE WIDESPREAD 20 TO 25 KNOT WINDS BY 10Z OR SO. SEAS WILL BUILD TO 6 TO 9 FT IN RESPONSE TO THE INCREASED FLOW. SOUTHERLY WINDS AHEAD OF THE APPROACHING COLD FRONT WILL INCREASE WINDS TO 25 TO 30 KNOTS WITH SEAS BUILDING 7-10 FT LATER TODAY. NO CHANGES TO THE CURRENT SCA HEADLINES BEGINNING OVERNIGHT. BLEND OF WW3...NWPS AND PREVIOUS FCST USED FOR SEAS. LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 330 PM SUN...SW WINDS WILL SLOWLY DIMINISH THROUGH MON EVENING THOUGH SEAS WILL REMAIN 6 FEET OR HIGHER THROUGH THE OVERNIGHT. HIGH PRES BUILDS IN FOR TUE BRINGING GOOD BOATING CONDITIONS. WEAK LOW PRES WILL DEVELOP DURING THE DAY WEDNESDAY ACROSS THE SOUTHERN NC COASTAL WATERS. THIS WILL BRING EASTERLY WINDS TO START ACROSS THE AREA. CONDITIONS LOOK TO REMAIN SUB SCA HOWEVER ON WED. DURING THE AFTERNOON AS THE LOW PULLS EASTWARD WINDS WILL SWITCH TO THE WEST AND THEN NORTHWEST BY EVENING. COULD BE A BRIEF PD WHERE WINDS NEAR 25 KT AND WAVES OF 6 FT OR HIGHER WED NIGHT INTO EARLY THUR. HIGH PRESSURE WILL BE IN CONTROL FOR THE REMAINDER OF THE WEEK BRINGING GOOD BOATING CONDITIONS. A STRONG COLD FRONT LOOKS TO MOVE THROUGH THE SECOND HALF OF THE WEEKEND BRINGING THE POTENTIAL FOR SCA WINDS/SEAS ON STRONG NW WINDS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 10 PM EST THIS EVENING FOR AMZ135. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS EVENING FOR AMZ130. SMALL CRAFT ADVISORY UNTIL 10 AM EST TUESDAY FOR AMZ152-154. SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ156-158. SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 4 AM EST TUESDAY FOR AMZ150. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...TL AVIATION...RSB/CTC/TL MARINE...RSB/CTC/TL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1240 AM EST MON FEB 11 2013 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH ACROSS THE AREA OVERNIGHT. RAIN IS EXPECTED TONIGHT INTO MONDAY AHEAD OF A PRE-FRONTAL TROUGH. A COLD FRONT WILL MOVE ACROSS THE AREA EARLY ON TUESDAY...BEFORE STALLING. A DEEPENING LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA ON WEDNESDAY...WITH HIGH PRESSURE RETURNING FOR THE END OF THE WEEK. AN ARCTIC BLAST MAY REACH THE EASTERN CAROLINAS IN THE WAKE OF A COLD FRONT NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 12:40 AM MONDAY...LIGHT RAIN HAS PROGRESSED EASTWARD ACROSS ALL BUT THE COASTAL COUNTIES. NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. LOOKS LIKE VIRTUALLY ALL AREAS...EXCEPT POSSIBLY FOR SPOTS IN GEORGETOWN COUNTY...WILL SEE RAIN OVERNIGHT. PREVIOUS DISCUSSIONS FOLLOW BELOW: THE FORECAST REMAINS ESSENTIALLY ON-TRACK THIS EVENING. REGIONAL RADAR COMPOSITES SHOW ECHOES NOT QUITE TO I-95...AND SURFACE OBS SHOW PRECIP IS REACHING THE GROUND UNDER ALL BUT THE 15 DBZ AND LOWER RADAR REFLECTIVITIES. THE LATEST SEVERAL RUNS OF THE RUC AND HRRR MODELS SUGGEST A LIGHTER-QPF EVENT THAN WAS INITIALLY THOUGHT...AND WITH A SOUTHWARD SHIFT IN THE LOCATION OF HEAVIEST RAINFALL IN THE 3-6 A.M. TIME FRAME. SINCE THIS IDEA APPEARS TO BE SUPPORTED BY LIGHT RADAR ECHOES OBSERVED AS FAR SOUTH AS AUGUSTA GA...I HAVE INCREASED POPS FOR THE SOUTHERN END OF THE SC PEE DEE REGION AND DOWN TO THE COAST BY 10-20 PERCENT...ALTHOUGH WITH NO ATTENDANT INCREASE IN FORECAST RAINFALL AMOUNTS. THE SYNOPTIC PATTERN HAS A WARM FRONT EXTENDING FROM JUST SOUTH OF CAPE LOOKOUT TO NEAR CAROLINA BEACH...THEN SOUTH-SOUTHWESTWARD JUST OFFSHORE FROM MYRTLE BEACH AND GEORGETOWN. IN RESPONSE TO STRENGTHENING SOUTH FLOW THE FRONT IS LIFTING NORTHWARD AT AN INCREASING RATE AND MAY "JUMP" NORTH THROUGH MY ENTIRE FORECAST AREA IN THE NEXT COUPLE OF HOURS. EASTERLY SURFACE WINDS WILL VEER SOUTHERLY AND INCREASE TO 10-15 MPH...WITH 20-25 MPH GUSTS POSSIBLE AFTER MIDNIGHT. A HEALTHY UPPER TROUGH EXTENDS SOUTHWARD FROM AN UPPER LOW IN SOUTHERN MINNESOTA. PLENTY OF GULF MOISTURE ADVECTED NORTH AHEAD OF THIS TROUGH IS PRODUCING SEVERE WEATHER AND HEAVY RAINFALL ACROSS THE DEEP SOUTH. ALTHOUGH THE AIRMASS OVER THE EASTERN CAROLINAS SHOULD REMAIN TOO STABLE FOR CONVECTION...THIS SAME MOISTURE FEED IS WHAT WILL CREATE OUR RAINFALL CHANCES TONIGHT. BY DAYBREAK RAINFALL AMOUNTS AROUND A HALF INCH ARE EXPECTED ACROSS DARLINGTON COUNTY... TAPERING DOWN TO AROUND A THIRD OF AN INCH FROM LUMBERTON INTO MARION AND FLORENCE. CLOSER TO THE COAST AND SOUTH TOWARD THE SANTEE RIVER RAINFALL AMOUNTS OF ONE OR TWO-TENTHS OF AN INCH ARE EXPECTED BY DAYBREAK. WE ARE AT OUR LOW TEMPERATURES CURRENTLY...AND READINGS SHOULD RISE BY 3-5 DEGREES OVER THE NEXT SEVERAL HOURS AS WARMER AIR FROM GEORGIA AND OFFSHORE SOUTH CAROLINA ADVECTS OVERHEAD. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...COMPLICATED AND CHALLENGING FORECAST PERIOD. FORECAST AREA WILL BE IN THE WARM SECTOR AHEAD OF PRE-FRONTAL TROUGH ON MON. EVEN WITH AN ABUNDANCE OF CLOUD COVER...CAPE VALUES MAY STILL REACH UP TO 500 J/KG MON AFTERNOON. DEEP MOISTURE WILL BE IN PLACE...WITH PRECIPITABLE WATER VALUES NEAR 1.5 INCHES. THE HIGHEST INSTABILITY WILL BE ACROSS THE SOUTHERN AND EASTERN ZONES...THUS ADDED ISOLATED THUNDERSTORMS TO THE FORECAST FOR MON AFTERNOON. GIVEN THE MAGNITUDE OF LIFT...HIGHLY CONFIDENT THERE WILL BE SHOWERS AND WILL CARRY CATEGORICAL POPS MON. AS THE PRESSURE GRADIENT TIGHTENS ON MON...SW LOW LEVEL JET WILL INCREASE TO 40 TO 50 KT AND EXPECT SOME WIND GUSTS ON MON TO AROUND 30 MPH. ONCE THE PRE-FRONTAL TROUGH MOVES THROUGH MON AFTERNOON/EARLY EVE...LASTLY ALONG THE COAST...DRIER AIR IN THE LOW AND MID LEVELS WILL WORK INTO THE FORECAST AREA. THIS DRIER AIR SHOULD LARGELY CUT OFF THE RISK FOR PRECIPITATION...BUT GIVEN THE ACTUAL FRONT WILL NOT LIMP INTO THE FORECAST AREA TIL TUE MORNING...WILL CARRY SMALL POPS FOR PORTIONS OF THE AREA EVEN AFTER DARK MON. ATTENTION THEN TURNS TO A SOUTHERN STREAM SYSTEM WHICH WILL BE DEVELOPING ALONG THE GULF COAST IN RESPONSE TO A HIGHLY ENERGIZED MID-LEVEL SHORTWAVE MOVING ACROSS THE SOUTHERN PLAINS TUE. THE EUROPEAN MODEL HAS BEEN THE MOST CONSISTENT AND CONTINUES TO INDICATE SURFACE LOW PRESSURE MOVING ALONG A STALLED FRONT AND REACHING THE SE STATES TUE NIGHT...BEFORE TRANSFERRING TO THE CAROLINA COAST DURING WED. STILL SOME DISCREPANCY AS TO HOW FAR N THE STRONGEST ISENTROPIC UPGLIDE WILL DEVELOP AND THUS WHERE THE HEAVIEST RAIN WILL DEVELOP. CONFIDENT THAT POPS...WHICH HAD BEEN TRENDED LOWER MON NIGHT INTO TUE...WILL BEGIN TO REVERSE HIGHER... FROM S TO N...TUE AFTERNOON AND ESPECIALLY TUE NIGHT. WILL BRING POPS BACK TO CATEGORICAL OVERNIGHT TUE INTO WED MORNING. THE CHARACTER OF PRECIPITATION THIS TIME AROUND SHOULD BE STRATIFORM AS LONG AS THE MORE SOUTHERN TRACK VERIFIES AND WILL NOT ADD THUNDERSTORMS TO THE TUE FORECAST AT THIS TIME. CONFIDENCE IN THE QPF FORECAST HAS NOT INCREASED...BUT AT THIS TIME WE ARE FORECASTING A 1 TO POSSIBLY 3 INCH RAINFALL EVENT THROUGH MID WEEK. THIS AMOUNT OF RAIN SHOULD NOT BE ENOUGH TO CAUSE FLOODING ALTHOUGH RIVERS WILL LIKELY BE ON THE RISE MID AND LATE WEEK. SHOULD SIGNIFICANTLY HIGHER RAINFALL AMOUNTS MATERIALIZE...THE RISK FOR SOME FLOODING WOULD INCREASE. LATER FORECASTS WILL STRIVE TO BETTER DEFINE THE TOTAL AMOUNT OF RAINFALL AND ANY FLOOD RISK. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...MAIN FOCUS WILL BE ON THE EARLY PART OF THE FORECAST WHERE POPS REMAIN A DILEMMA AND THE END OF THE PERIOD WHERE ARCTIC AIR WILL BE AN ISSUE. FOR WEDNESDAY...THERE REMAINS A DIFFERENCE IN MEDIUM RANGE GUIDANCE AS THE ECMWF IS LESS AMPLIFIED AND HENCE MORE PROGRESSIVE WITH THE MAIN UPPER LEVEL FEATURE MOVING ACROSS THE TENNESSEE VALLEY. THE GFS REMAINS CONSISTENT WITH A SLOWER AND DEEPER SOLUTION. I HAVE MAINTAINED THE INHERITED CATEGORICAL POPS BASED PRIMARILY ON CONTINUITY OF THE GFS ALTHOUGH IT SHOULD BE NOTED CONFIDENCE EVEN JUST A FEW DAYS OUT REMAINS UNUSUALLY LOW. FOR THURSDAY THROUGH SATURDAY...A BROAD EASTERN U.S. TROUGH DEVELOPS WITH SURFACE HIGH PRESSURE CENTERED ACROSS THE SOUTHERN U.S. EXPECT TEMPERATURES AT OR JUST BELOW CLIMATOLOGY ALONG WITH DRY CONDITIONS. AS THE EASTERN PACIFIC RIDGE DEVELOPS THROUGH THE PERIOD... SEVERAL SHORTWAVES WILL DIVE SOUTH AND REINFORCE THE BROAD TROUGH THUS RELEASING A SHOT OF ARCTIC AIR. THE 0600 OPERATIONAL GFS WAS ADVERTISING 850MB TEMPERATURES AS COLD AS MINUS 15 DEGREES C MOVING ACROSS THE AREA BRIEFLY NEXT SUNDAY. HOWEVER THE 1200 UTC GUIDANCE HAS MODERATED SOMEWHAT AND THESE NUMBERS APPEAR MORE REASONABLE. ACTUAL LOWS WILL BE MODULATED BY DECOUPLING OR LACK THEREOF. IT HAS ALSO BEEN MY EXPERIENCE IN THE PAST THAT ARCTIC AIR OUTBREAKS LATER IN THE SEASON WITH THE HIGHER SUN ANGLES MAKE MEX NUMBERS MORE ACCURATE. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...CURRENTLY VFR AT ALL TERMINALS. A LARGE AREA OF RAIN IS MOVING ACROSS THE KFLO/KLBT TERMINALS TOWARDS THE COASTAL TERMINALS. CONFIDENCE IS HIGH THAT FLIGHT CONDITIONS WILL DETERIORATE TO MVFR DUE TO MAINLY REDUCED VSBYS IN RAIN AND BR AT KFLO/KLBT EARLY THIS MORNING. THE HEAVIEST OF THE RAIN SHOULD OCCUR 08Z-14Z AND IT IS DURING THIS TIME THAT THE GREATEST THREAT OF IFR WILL OCCUR. MOST OF THE RAIN SHOULD END BY 14Z BUT THERE WILL REMAIN A GOOD CHANCE OF MVFR CONDITIONS/SHOWERS THROUGH 19Z AND MVFR CIGS THROUGH 22Z. THERE IS HIGH CONFIDENCE OF MVFR CONDITIONS DEVELOPING AT THE COASTAL TERMINALS BY 08-09Z. THE HEAVIEST OF RAIN SHOULD OCCUR IN THE 12Z-17Z TIME FRAME. IT IS DURING THIS TIME THE GREATEST THREAT OF IFR WILL OCCUR. THERE MAY BE A TEMPO LULL IN PRECIPITATION INTENSITY BY 16-17Z...BUT THERE WILL REMAIN A GOOD CHANCE OF TEMPO IFR/SHOWERS THROUGH 20-21Z...AND MVFR CIGS THROUGH THE EVENING. EXTENDED OUTLOOK...RAIN LIKELY WITH PERIODS OF MVFR/IFR CONDITIONS THROUGH WEDNESDAY. VFR DEVELOPING THURSDAY AND PERSISTING THROUGH FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 12:40 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. SMALL CRAFT ADVISORY REMAINS IN EFFECT. LATEST OBS SHOW 3 TO 5 FT SEAS BUT WINDS ARE STILL ON THE INCREASE. PREVIOUS DISCUSSION FOLLOWS BELOW: THE WARM FRONT IS FINALLY BEGINNING TO MAKE A MOVE TO THE NORTH...CURRENTLY EXTENDING FROM JUST SOUTH OF CAPE LOOKOUT TO NEAR CAROLINA BEACH...THEN SOUTH-SOUTHWESTWARD THROUGH THE SOUTH CAROLINA COASTAL WATERS REMAINING JUST EAST OF GEORGETOWN. ON THE COOL SIDE OF THIS BOUNDARY SURFACE WINDS REMAIN EASTERLY. THE SOUTHERLY WINDS OVER THE FRONT ARE ERODING THE COOLER SURFACE AIR RATHER QUICKLY...AND THE FRONT SHOULD "JUMP" NORTH ACROSS MY FORECAST AREA IN THE NEXT SEVERAL HOURS...WITH SOUTHERLY WINDS AT THE SURFACE THE ANTICIPATED RESULT. WIND SPEEDS SHOULD INCREASE TO 20-25 KT...BUT WITHOUT ANY SUBSTANTIAL GUSTINESS GIVEN VERY STABLE THERMODYNAMIC PROFILES. SEAS CURRENTLY 3-4 FT WILL BEGIN TO BUILD SUBSTANTIALLY AFTER MIDNIGHT AND COULD REACH 8 FEET ACROSS THE OUTER PORTION OF THE COASTAL WATERS BY DAYBREAK MONDAY. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...A MOIST AND INCREASING SOUTHERLY FLOW WILL DEVELOP AHEAD OF A PRE-FRONTAL TROUGH. SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO HAVE ALREADY BEGUN BY THE START OF THE PERIOD AND TO CONTINUE INTO MON NIGHT...SSW TO SW WINDS TO 20 TO 25 KT WITH SEAS PEAKING IN THE 6 TO 10 FT RANGE...HIGHEST ACROSS THE OUTER NORTHERN WATERS. DECREASING WINDS WILL VEER TO W BEHIND THE PRE-FRONTAL TROUGH MON EVE AND THEN BECOME NW BEHIND A COLD FRONT TUE MORNING. WINDS AND SEAS ARE EXPECTED TO FALL BELOW ADVISORY CRITERIA LATE MON NIGHT. SINCE DEWPOINTS WILL BE CLIMBING INTO THE LOWER 60S...THERE IS SOME RISK FOR THE DEVELOPMENT OF SEA FOG ON MON. AT THIS TIME...GIVEN THE MAGNITUDE OF WIND...WILL OPT FOR STRATUS OVER FOG AND WILL LEAVE OUT OF THE FORECAST. AS LOW PRESSURE APPROACHES FROM THE W AND SW TUE NIGHT...WINDS WILL SHIFT TO THE NE AND THEN ENE...INCREASING WITH THE APPROACH OF DAYBREAK WED. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...CHANGEABLE CONDITIONS AT LEAST THROUGH THE EARLY PART OF THE PERIOD...WILL BE THE HIGHLIGHT OF THE FORECAST. EASTERLY FLOW INITIALLY WILL QUICKLY GIVE WAY TO A SOUTHERLY FLOW BY MIDDAY WEDNESDAY AS A WARM FRONT MOVES ACROSS TO THE NORTH. WINDS THEN QUICKLY VEER TO WEST NORTHWEST BY EARLY THURSDAY AS A COLD FRONT MOVES ACROSS. BY FRIDAY WINDS ESSENTIALLY BECOME LIGHT AND VARIABLE AS HIGH PRESSURE DRIFTS OVERHEAD. FOR SEAS...SOME RESIDUAL SIX FOOTERS MAY WARRANT AN ADVISORY FOR PART OR MOST OF WEDNESDAY ESPECIALLY ACROSS THE OUTER WATERS BUT LATER THURSDAY AND FRIDAY OFFER MORE BENIGN VALUES WITH THE DIMINISHING OFFSHORE FLOW. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR AMZ250-252-254- 256. && $$ NEAR TERM...REK/JDW SHORT TERM...RJD LONG TERM...SHK AVIATION...MRR MARINE...REK/RJD/JDW/SHK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1214 AM CST MON FEB 11 2013 .DISCUSSION...LATEST WATER VAPOR IMAGERY SHOWS THE UPPER LOW CIRCULATION ALONG THE CENTRAL MINNESOTA/WISCONSIN BORDER WITH A TROWAL EXTENDING INTO FAR EASTERN NORTH DAKOTA. THIS WOULD RESULT IN THE SNOW TO CONTINUE TAPERING OFF IN THE JAMES RIVER VALLEY THROUGH 12Z. COLLABORATED WITH NEIGHBORING OFFICES AND WILL CONTINUE WITH THE CURRENT HEADLINES. VISIBILITIES AROUND ONE MILE IN THE BLIZZARD WARNING BUT IN BETWEEN REPORTING STATIONS AND IN THE OPEN COUNTRY VISIBILITIES COULD POSSIBLY BE LOWER AS WINDS CONTINUE TO GUST NEAR 40 MPH. THE FOG/STRATUS LOOP SHOWS PLENTY OF CLOUD COVER EXTENDING INTO CENTRAL MONTANA AND INTO SASKATCHEWAN AND MANITOBA. LATEST RAP AND NAM 925MB RH FIELD KEEPS THE STRATUS THROUGH 18Z BEFORE ERODING IT ALONG THE EDGES LATER MONDAY AFTERNOON. && .AVIATION...IFR/MVFR CONDITIONS WILL PERSIST AT ALL AERODROMES THROUGH AT LEAST 18Z MONDAY...WITH IMPROVEMENTS TO VFR AT KISN AND KDIK BETWEEN 18Z AND 21Z MONDAY. BLOWING SNOW WILL CONTINUE AT KJMS THROUGH 15Z MONDAY RESULTING IN IFR TO LIFR VSBYS. && .BIS WATCHES/WARNINGS/ADVISORIES... BLIZZARD WARNING UNTIL 6 AM CST MONDAY FOR NDZ037-047-048-050- 051. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR NDZ025-036-046. && $$ DISUCSSION...KS AVIATION...RK/KS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1238 AM EST MON FEB 11 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE AREA TONIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA ON MONDAY AND REMAIN ACROSS THE REGION FOR TUESDAY. A STORM SYSTEM WILL MOVE SOUTH OF THE AREA ON WEDNESDAY BRINGING A CHANCE FOR PRECIPITATION TO SOUTHERN PORTIONS OF THE REGION. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... MAIN AREA OF PCPN IS EXITING OUR EASTERN AREAS SO WILL TRIM BACK POPS ACROSS THE EAST IN THE SHORT TERM. PCPN IS TRYING TO FILL IN ACROSS INDIANA AS SUGGESTED BY THE NAM AND HRRR BUT SO FAR IT STILL APPEARS TO BE PRETTY LIGHT. WILL ALLOW FOR CHANCE POPS ASSOCIATED WITH THIS TO SPREAD BACK EAST ACROSS OUR AREA THROUGH THE LATE EVENING AND ON INTO THE EARLY MORNING HOURS BUT EXPECT ANY MEASURABLE PCPN TO BE ON THE LIGHT SIDE. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... HIGH PRESSURE WILL BEGIN TO WORK INTO THE FA ON MONDAY. THERE WILL BE A BREAK IN THE CLOUDS DURING THE MORNING HOURS ACROSS THE FA. IT IS DURING THIS TIME THAT WINDS WILL INCREASE ACROSS THE FA AND EXPECT THE HIGHEST WINDS ACROSS THE FA DURING THE LATE MORNING TO EARLY AFTERNOON TIME FRAME. SUSTAINED WINDS WILL BE AROUND 20 TO 25 MILES PER HOUR WITH WIND GUSTS AROUND 35 TO 45 MILES PER HOUR. THESE WINDS FALL SLIGHTLY BELOW WIND ADVISORY CRITERIA AND THEREFORE DECIDED NOT TO ISSUE A WIND ADVISORY FOR MONDAY. WILL CONTINUE TO HIGHLIGHT THE WINDS IN THE HWO. ADDITIONAL CLOUDS WILL WORK INTO THE AREA FOR THE AFTERNOON HOURS. GUSTY WINDS WILL REMAIN ACROSS THE FA THROUGH THE AFTERNOON AND EVENING HOURS. WINDS WILL DECREASE ACROSS THE AREA MONDAY NIGHT. TEMPERATURES ON MONDAY WILL NOT RISE MUCH FROM SUNDAY NIGHT LOWS. EXPECT HIGH TEMPERATURES ON MONDAY TO BE IN THE LOW TO UPPER 40S. WITH CLOUD COVER DECREASING ACROSS THE FA MONDAY NIGHT TEMPERATURES WILL DROP DOWN INTO THE 20S ACROSS MOST LOCATIONS. HIGH PRESSURE WILL KEEP DRY CONDITIONS ACROSS THE FA TUESDAY AND INTO TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE WILL PASS SOUTH OF THE REGION ON WEDNESDAY. STILL SOME MODEL DISAGREEMENT ON HOW FAR NORTH THE PRECIPITATION SHIELD WILL SPREAD. HAVE LIMITED POPS TO THE FAR SOUTH/SOUTHEASTERN COUNTIES. LOOKS LIKE THIS WOULD BE A MIX OF LIGHT SNOW AND RAIN. ONCE THIS SYSTEM MOVES OFF THERE WILL BE A BRIEF PERIOD OF RIDGING ON THURSDAY. BUT THEN LOW PRESSURE WILL TRACK ACROSS THE GREAT LAKES ON FRIDAY WHICH WILL SWING A COLD FRONT THROUGH THE REGION. COLD NORTHWEST FLOW WILL THEN PREVAIL THROUGH THE WEEKEND. COULD SEE SOME SNOW SHOWERS OR FLURRIES WITH THE FRONT AND INTO THE WEEKEND. BUT NARROWING DOWN A MORE FAVORABLE PERIOD FOR MEASURABLE PRECIPITATION IS PROBLEMATIC THIS FAR OUT IN TIME. SO KEPT POPS MAINLY IN SLIGHT CHANCE CATEGORY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... MVFR CEILINGS LINGER IN A MOIST SOUTHERLY FLOW ALONG AND AHEAD OF A COLD FRONT. SHOWERS HAVE JUST ABOUT ENDED THOUGH SOME LIGHT RAIN MAY PERSIST AT CMH AND LCK. CONDITIONS WILL IMPROVE TO VFR BY MID MORNING AS THE FRONT PROGRESSES EAST AND DRIER AIR WORKS IN. WINDS WILL BE A PROBLEM WITH GUSTS OVER 30 KNOTS OUT OF THE SOUTHWEST EXPECTED IN A TIGHT PRESSURE GRADIENT BEHIND THE FRONT. WINDS WILL SUBSIDE TO AROUND 12 KNOTS ABOUT 00Z AS DIRECTION SHIFTS TO WEST. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...NOVAK NEAR TERM...JGL SHORT TERM...NOVAK LONG TERM... AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1147 PM EST SUN FEB 10 2013 .SYNOPSIS... LOW PRESSURE TRACKING OUT OF THE PLAINS WILL MOVE THROUGH THE UPPER GREAT LAKES ON MONDAY...PULLING AWAY TO THE NORTHEAST ON TUESDAY. A RIDGE WILL EXPAND NORTH ACROSS THE OHIO VALLEY ON TUESDAY AND LINGER INTO WEDNESDAY. A CLIPPER WILL APPROACH THE REGION FROM THE NORTHWEST ON THURSDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... THE FRONT WILL MOVE ACROSS THE AREA LATE TONIGHT AND MONDAY MORNING. THE FIRST BATCH OF SHOWERS HAVE DECREASED...SOME SPRINKLES COULD BE OCCURRING OVER NW PA THROUGH MIDNIGHT. THE DEW POINTS ARE LOW OVER NW PA BUT THE TEMPERATURES ARE WARM ENOUGH AND WILL CONTINUE TO RISE AS WILL THE DEW POINTS. THE THREAT OF THE TEMPERATURE DROPPING TO 32F IS NEGLIGIBLE. ALSO THE ROAD TEMPERATURES ARE NEAR 40F...SO THAT WILL ALSO HELP PREVENT ANY ICY ROADS. THE NEXT BATCH OF SHOWERS WERE TRYING TO DEVELOP OVER WESTERN OHIO. THE HRRR MODEL IS HINTING AT IT...MORE OF A SCATTERED NATURE. THE 12Z 4KM WRF NMM MODEL IS HINTING AT WIDESPREAD SHOWERS DEVELOPING AFTER MIDNIGHT. THAT IS POSSIBLE WITH ENOUGH MOISTURE...PLENTY OF OMEGA AND SOME LOW LEVEL AND UPPER JET HELP...LEFT FRONT QUAD OF THE JET. KEPT THE POPS LIKELY FOR THE OVERNIGHT. CONFIDENCE IS LOW TO MODERATE. RAINFALL AMOUNTS WILL BE UNDER TWO TENTHS OF AN INCH. ADJUSTED SOME OF THE LOWS BASED ON A SLOWER TIMING OF THE FRONT. ALSO REMOVED THE MENTION OF THUNDER AS THE AIRMASS IS TOO STABLE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/... BY MONDAY MORNING THE MID-LEVEL DRY SLOT WILL HAVE SPREAD EAST ACROSS OUR ENTIRE FORECAST AREA WITH DRY CONDITIONS IN MOST AREAS. HAVE LOWERED POPS IN THE EAST TO JUST A LOW CHANCE AFTER 12Z. THE COLD FRONT WILL MOVE INTO NW OHIO TOWARDS 14Z...CLEARING NW PA DURING THE EARLY AFTERNOON. LOW LEVEL WRAP AROUND MOISTURE WILL INCREASE WITH THE FRONT WITH FAIRLY STEEP LOW LEVEL LAPSE RATES AND ONLY A SLIGHT CHANCE OF RAIN...EVENTUALLY COOLING ENOUGH FOR FLURRIES OR A STRAY SNOW SHOWER LATE. HAVE ISSUED A WIND ADVISORY FOR THE WESTERN HALF OF THE AREA AND LAKESHORE COUNTIES WITH BOTH THE NAM/GFS ADVERTISING A MIXED LAYER TO NEARLY 850MB WHERE WINDS INCREASE TO 50 KNOTS. WITH LITTLE IN THE WAY OF DOWNWARD MOMENTUM WILL HAVE TO RELY ON THE TIGHT PRESSURE GRADIENT AND MECHANICAL MIXING TO SEE THE STRONGER WINDS MATERIALIZE AT THE SURFACE. STILL EXPECTING TO SEE SOUTHWEST WINDS OF 20-30 MPH WITH GUSTS NEAR 50 MPH. TEMPERATURES BEHIND THE LAKE WILL BE MARGINAL FOR LAKE EFFECT BUT ENOUGH CONVERGENCE ALONG THE SHORELINE SHOULD BE ENOUGH FOR LINGERING SNOW SHOWERS EXTREME NE OHIO/NW PA. NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION. A RIDGE WILL EXPAND NORTH OVER THE AREA THROUGH TUESDAY WITH SNOW SHOWERS ENDING BY TUESDAY NIGHT. A SHORTWAVE DROPS THROUGH THE NORTHWEST FLOW ON TUESDAY AND HELPS TO RE-ENFORCE THE TROUGH OVER THE GREAT LAKES. THIS SHOULD HELP TO KEEP LOW PRESSURE SYSTEM EAST OF THE APPALACHIANS ON WEDNESDAY. && .LONG TERM /THURSDAY THROUGH SUNDAY/... THE MODELS HAVE BEEN PRETTY CONSISTENT DEEPENING THE TROUGH ALOFT LATE IN THE WEEK. THE FIRST IN A SERIES OF COLD FRONTS SEEMS TO CROSS THE AREA LATE THURSDAY. NOT MUCH MOISTURE AVAILABLE AND THE FRONT IS WEAK AND WILL HAVE JUST A SLIGHT CHANCE OF SHOWERS THURSDAY AFTERNOON...WITH A CHANCE OF SOME SNOW SHOWERS DEVELOPING THURSDAY NIGHT. APPEARS AS THOUGH A REINFORCING PUNCH OF COLDER AIR WILL ARRIVE FRIDAY AND WILL HAVE A CHANCE OF SNOW SHOWERS FOR THE ENTIRE FORECAST AREA ALTHOUGH AS WE GET CLOSER WE WILL PROBABLY NEED "LIKELY" POPS...PROBABLY AT LEAST FOR NE OH/NW PA. A LITTLE NERVOUS WITH SUCH A DEEP TROUGH PROGGED BY THE WEEKEND THAT SOME CYCLOGENESIS COULD OCCUR BUT PERHAPS IT IS ALL TO THE EAST NEAR THE COAST? IN ANY CASE...WE WILL CONTINUE TO SEE SNOW FLURRIES AND LAKE EFFECT SNOW SHOWERS THIS WEEKEND. NUDGED TEMPERATURES DOWN A COUPLE OF CATEGORIES BY THE WEEKEND WITH HIGHS IN THE 20S AND LOWS MOSTLY IN THE TEENS. WE CAN REFINE THE FORECAST AS WE GET CLOSER. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... ACTIVE CONVECTION ACROSS THE SOUTH CUT OFF THE MOISTURE SOURCE INTO OUR REGION AND HENCE CUT WAY BACK ON THE PRECIPITATION AMOUNTS. VIRTUALLY REMOVED THREAT FOR PRECIPITATION AT ALL AREAS EXCEPT FOR ERIE. CEILINGS AND VISIBILITIES WILL DROP INTO MVFR CATEGORY OVERNIGHT WITH SOME IMPROVEMENT DURING THE DAY ON MONDAY. WINDS ARE GOING TO BE THE PROBLEM OVERNIGHT INTO TOMORROW AS THEY BECOME QUITE GUSTY FROM THE SOUTH TO SOUTHWEST. OTHER PROBLEM WILL BE WIND SHEAR POTENTIAL AT ALL SITES EXCEPT ERIE. EXPECTING SURFACE WINDS TO BE RELATIVELY LIGHT BUT THEN INCREASE IN SPEED DRAMATICALLY TO AROUND 50 KNOTS JUST ABOVE THE SURFACE. THEREFORE...WILL KEEP MENTION OF WIND SHEAR OVERNIGHT. SURFACE TROUGH MOVES THROUGH THE REGION TOMORROW AND WILL LIKELY CAUSE CEILINGS AND POSSIBLY VISIBILITIES TO LOWER ONCE AGAIN. THERE IS THE POSSIBILITY FOR SOME SNOW AGAIN TOMORROW AFTERNOON WITH THE TROUGH AT ERIE. OUTLOOK...NON-VFR MONDAY NIGHT AND CONTINUING INTO TUESDAY. && .MARINE... STRONG LOW PRESSURE WILL TRACK ACROSS THE NORTHERN GREAT LAKES LATER TONIGHT AND MIDDAY. THE ASSOCIATED COLD FRONT WILL SWING ACROSS LAKE ERIE MONDAY MORNING. AS THE COLD ADVECTION DEVELOPS THE HIGHER WINDS WILL MIX DOWN TO THE SURFACE AND GALE FORCE WINDS ARE LIKELY MONDAY AFTERNOON INTO MONDAY NIGHT. THE ICE ON THE LAKE WILL LIKELY SHIFT MONDAY INTO TUESDAY. THE LOW WILL PULL OUT QUICKLY ON TUESDAY AND HIGH PRESSURE WILL BUILD IN FROM THE WEST AND THE MIDDLE OF THE WEEK SHOULD BE RELATIVELY QUIET ON THE LAKE. A SERIES OF COLD FRONTS AND CLIPPER LOW PRESSURE SYSTEMS ARE EXPECTED LATE IN THE WEEK. THE SOUTHWEST FLOW WILL SHIFT TO NORTHWEST AND WINDS WILL INCREASE LATE IN THE WEEK... PROBABLY IN THE 15 TO 30 KNOT RANGE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...WIND ADVISORY FROM 11 AM MONDAY TO 1 AM EST TUESDAY FOR OHZ011- 012-089. WIND ADVISORY FROM 9 AM TO 7 PM EST MONDAY FOR OHZ003-006>010- 017>020-027>030-036-037. PA...WIND ADVISORY FROM 11 AM MONDAY TO 1 AM EST TUESDAY FOR PAZ001. MARINE...GALE WARNING FROM NOON MONDAY TO 4 AM EST TUESDAY FOR LEZ061- 142>149-162>169. && $$ SYNOPSIS...KEC NEAR TERM...KIELTYKA SHORT TERM...KEC LONG TERM...KOSARIK AVIATION...LOMBARDY MARINE...KOSARIK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
108 AM EST MON FEB 11 2013 .SYNOPSIS... A FRONTAL SYSTEM WILL MOVE THROUGH THE AREA LATER TODAY...FOLLOWED BY WINDY AND COLDER CONDITIONS TONIGHT INTO TUESDAY. LOW PRESSURE OVER THE GULF COAST IS EXPECTED TO TRACK TOWARD THE CAROLINAS ON WEDNESDAY...BEFORE MOVING OFF THE SOUTHERN MID-ATLANTIC COAST WEDNESDAY NIGHT. IT MAY GET CLOSE ENOUGH TO AFFECT SOUTHERN PENNSYLVANIA. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... EVENING SATL LOOP SHOWING UPPER LOW LIFTING NE INTO S MINNESOTA. ASSOCIATED LL JET AND PLUME OF MOISTURE AHEAD OF THIS FEATURE CAN BE TRACED ALL THE WAY BACK TO THE EASTERN PACIFIC. ALTHOUGH PWATS ALONG THIS LL JET ARE 2-3 STD ABV NORMAL...IT SHOULD PASS RATHER QUICKLY THRU CENTRAL PA LATE TONIGHT AND EARLY MON AM. THEREFORE... PRECIP AMTS NOT EXPECTED TO BE HEAVY. 18Z GEFS MEAN QPF RANGES FROM ARND A QUARTER INCH ACROSS THE NORTH CENTRAL MTNS...TO ALMOST 0.75 INCHES ACROSS LANCASTER CO. ALTHOUGH SURGE OF WARM AIR ALOFT ASSOC WITH LL JET SHOULD ENSURE LIQUID PRECIP...MDL SOUNDINGS CONTINUE TO INDICATE ENOUGH COLD AIR NR GROUND LVL FOR A PERIOD OF FZRA. 00Z PIT SOUNDING SHOWS PLENTY OF DRY AIR IN THE LOW LVLS. SO EVEN THOUGH TEMPS ARE CURRENTLY ABV FREEZING OVR MOST OF CENTRAL PA UNDER WAA AND OVERCAST SKIES...EXPECT EVAPORATIVE COOLING TO LOWER SFC TEMPS JUST BLW 0C AS RAIN ARRIVES OVERNIGHT. REGIONAL RADAR AND LATEST RAP INDICATE FZRA/RA WILL OVERSPREAD THE W MTNS ARND MIDNIGHT...THEN SPREAD INTO THE SUSQ VALLEY BY 3 OR 4 AM. SREF/GEFS AND 18Z OPER RUNS ALL POINT TOWARD A MARGINAL ICING EVENT...WITH TEMPS VERY CLOSE TO FREEZING OVERNIGHT...THEN RISING BY DAWN. BY 12Z...BULK OF MDL DATA INDICATES ONLY THE HIGH TERRAIN OF NORTH CENTRAL PA WILL REMAIN BLW FREEZING. SO...I ENVISION WE WILL BE ABLE TO CHIP AWAY AT THE ADVISORY FROM SW TO NE DURING THE EARLY AM HOURS. GIVEN THE MARGINAL TEMPS...EXPECT ICE ACCRETION RATES TO BE LOW AND NOT APPROACH THE LIQUID PRECIP FORECAST MENTIONED ABOVE. ICE AMOUNTS SHOULD RANGE FROM A TRACE TO A TENTH OF AN INCH...WITH THE LEAST AMTS WEST OF THE ALLEGHENIES ARND CONFLUENCE. && .SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/... SHORT RANGE OPERATIONAL MODELS ARE PRETTY AGREEABLE WITH THE LL JET AND PLUME OF ANOMALOUS PWATS SWEEPING EAST OF THE AREA BTWN 12Z-15Z...CAUSING RA/FZRA TO TAPER OFF. ANY ZR ONGOING AFTER 6AM SHOULD QUICKLY CHANGE TO PLAIN RAIN AS TEMPS RISE INTO THE LOW TO MID 30S BY MID MORNING. THE DRY SLOT SOUTH OF UPPER LOW SHOULD WORK INTO CENTRAL PA BY LATE AM...SHUTTING THE PRECIP OFF AND BRINGING PARTIAL CLEARING...ESP DOWNWIND /EAST/ OF THE ALLEGHENIES. MDL DATA INDICATES MUCH OF CENTRAL PA WILL BRIEFLY BREAK INTO THE WARM SECTOR MON AFTN WITH GEFS 925 TEMPS SUPPORTIVE OF HIGHS AOA 50F ACROSS SOUTHERN PA. BY LATE IN THE DAY...SFC COLD FRONT WILL PUSH INTO WESTERN PA... ACCOMPANIED BY SCT -SHRA/SN AND A GUSTY WIND SHIFT FROM SW TO WEST. DON/T EXPECT ANY SNOW ACCUMS...AS SFC TEMPS SHOULD REMAIN WELL ABV FREEZING THRU EARLY EVENING...EVEN OVR THE NW MTNS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... A FAIRLY AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. NUMEROUS NORTHERN AND SOUTHERN STREAM SHORTWAVES WILL BRING SEVERAL CHANCES FOR PCPN TOWARD PA DURING THE PERIOD... THOUGH AT THIS POINT IN TIME SIGNIFICANT PCPN EVENTS DO NOT APPEAR DESTINED FOR THE COMMONWEALTH...AT LEAST NOT DIRECTLY. AN ABUNDANCE OF SRN STREAM FLOW WILL BRING INTRUSIONS OF ABOVE FREEZING TEMPERATURES TO THE REGION...FURTHER COMPLICATING THE LONG TERM FORECAST DETAILS. PHASING ENERGY MAY SUPPORT A NEARLY FULL LATITUDE TROF SPREADING EASTWARD INTO THE EASTERN U.S. BY NEXT WEEKEND...LEADING TO PERHAPS THE HIGHEST POTENTIAL OF SIGNIFICANT PCPN POTENTIAL IN THE LONG TERM PERIOD. LAKE EFFECT SHOWERS WILL BE ONGOING IN THE WEAK OF MONDAYS SYSTEM/COLD FROPA. A WEAK RIDGE OF HIGH PRESSURE SLIDES NE ACROSS THE STATE TUESDAY NIGHT BRINGING AN END TO THE SNOW SHOWERS. THE NEXT SYSTEM HEADED OUR WAY FOR WEDNESDAY AFTERNOON INTO EARLY THURSDAY IS TIED TO A RATHER VIGOROUS SOUTHERN STREAM JET EXIT REGION. THE NOSE OF THIS 140 KT JET WILL LIFT TWD THE CENTRAL APPALACHIANS DURING THE DAY WEDNESDAY. DETAILS OF THE EXACT PRESSURE PATTERN AND TIMING OF A WEAK SFC LOW WEST OF THE APPALACHIANS PER THE 06Z NAM /AND SECONDARY DEVELOPMENT NEAR THE VA COAST/ ARE STILL A BIT SKETCHY. LATEST...00Z GEFS IS A BIT OMINOUS AS ABOUT 20-25 PERCENT OF ITS MEMBERS CONTAIN AROUND AN INCH OF QPF IN THE FORM OF SNOW LATE WEDNESDAY INTO THURSDAY. SOME VARIATIONS IN THE TIMING OF THIS PRECIP ARE ALSO NOTED. MEAN TRACK OF THE 850 MB LOW CENTER ON THE GEFS TAKES IT ACROSS ERN VA AND SOUTHERN DELAWARE ALONG WITH A SLIGHTLY ANOMALOUS EASTERLY WIND AT THAT PRESSURE LEVEL. THE GEFS CONSENSUS QPF IS AROUND 0.25 INCH FOR THE LOWER SUSQ VALLEY WITH SHARPLY LESSER AMOUNTS TO THE NW. PAINTED HIGH CHC TO LOW LIKELY POPS INTO OUR GRIDDED DATABASE FOR THE SE THIRD TO HALF OF THE CWA...CENTERED ON WED NIGHT WITH A RESULTANT 1-3 INCHES OF SNOW. THIS SYSTEM BEARS CLOSE WATCHING AS ANY INTERACTION WITH AN UPSTREAM WAVE IN THE NRN BRANCH COULD HELP TO INVIGORATE THE COASTAL LOW AND LLVL EASTERLY FLOW BRINGING MORE SNOW TO THE SERN ZONES...AND SPREADING LIGHT SNOWS OVER THE I-80 CORRIDOR. ITS CURIOUS TO NOTE THAT THE 00Z OPERATIONAL EC /THAT INITIALLY HANDLED THE RECENT NEW ENGLAND BLIZZARD MUCH BETTER THAN THE U.S MODELS/ IS 12-18 HOURS FASTER...AND A FEW HUNDRED KM FURTHER SOUTH WITH THE SFC/UPPER WAVE TRACK...AND JUST BRUSHES THE MASON/DIXON LINE WITH SOME LIGHT SNOW AT THE NRN EDGE OF THE PRECIP SHIELD. THE AFOREMENTIONED BROAD LONGWAVE TROF MOVED ACROSS THE REGION THURSDAY INTO NEXT WEEKEND...WITH A RETURN OF ARCTIC AIR. WITH THE TROF WILL BE SIGNIFICANT NRN STREAM ENERGY AND AT LEAST ONE CLIPPER SYSTEMS MOVING ACROSS NW PA ON FRIDAY WITH LE SNOW SHOWERS PERSISTING INTO NEXT WEEKEND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... SIGNIFICANT CHANGES WERE MADE TO THE 06Z TAFS. PCPN HAS ARRIVED A LITTLE EARLIER THAN FCST...AND TIMING OF THICKENING CLOUDS LAST EVE HAS PRESERVED TEMPS MAINLY ABV 32F. IN ADDITION...DEWPT DEPRESSION ARE RUNNING 10-15 DEGREES. THEREFORE...THERMAL PROFILES ARE NO LONGER THAT FAVORABLE FOR -FZRA AND WOULD TEND TO LEAN TOWARD -RA OR -PL PTYPES DUE TO EVAPORATIVE COOLING IN THE LOW LEVELS. REMOVED -FZRA AND WENT WITH PLAIN RAIN FOR PREVAILING PRES WX...WITH SOME SITES REPORTING "UP" (SLEET) FOR A BRIEF PERIOD. KEPT LLWS AS 40-50KT SWLY LLJ TRANSLATES EWD AHEAD OF THE APPROACHING COLD FRONT. VFR CIGS SHOULD DROP TO MVFR WITH GUIDANCE SUGGESTING AN OUTSIDE CHC FOR IFR AT LNS/MDT. SFC WINDS WILL SHIFT FROM S/SE TO WSW LATER TDY...VEERING MORE TO THE WEST AND INCREASING INTO TONIGHT. OUTLOOK... TUE...MVFR CIGS NORTH/WEST. VFR EAST. WED...DEVELOPING VFR TO START THE DAY. LOWER CONDITIONS POSSIBLE OVER THE SOUTH BY LATE DAY AS A STORM SYSTEM SKIRTS THE REGION. THUR...MAINLY VFR. FRI...MVFR/IFR DEVELOPING OVER THE WEST AND CENTRAL TERMINALS. VFR EAST. WINDY. && .CTP WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046- 049>053-056>059-063>066. && $$ SYNOPSIS...STEINBUGL NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1142 PM CST SUN FEB 10 2013 .DISCUSSION... SEE AVIATION SECTION. && .AVIATION... VFR CONDITIONS WILL PREVAIL AT THE TAF SITES OVERNIGHT THROUGH MONDAY AFTERNOON. HIGH CLOUD COVERAGE WILL INCREASE OVERNIGHT WHILE PATCHY MID-LEVEL CLOUDS DEVELOP. A FEW SPRINKLES OR A BRIEF LIGHT RAIN SHOWER ARE A POSSIBILITY AT KBBD...KJCT AND KSOA. A BACK DOOR TYPE COLD FRONT WILL SAG SOUTH ACROSS THE BIG COUNTRY OVERNIGHT...AND SHOULD BECOME NEARLY STATIONARY ACROSS THE NORTHERN CONCHO VALLEY AND HEARTLAND AREAS ON MONDAY. AT KABI...WINDS WILL BECOME EAST OVERNIGHT AND REMAIN MOSTLY FROM THE EAST ON MONDAY. LIGHT WINDS AT THE OTHER TAF SITES OVERNIGHT WILL BECOME EAST TO SOUTHEAST ON MONDAY. CLOUD CEILINGS WILL DECREASE MONDAY EVENING AND MONDAY NIGHT...AND ARE EXPECTED TO BE IN THE RANGE OF 2500-3500 FT DURING THE FINAL 4-6 HOURS OF THE TAF PERIOD. SCATTERED RAIN SHOWERS ARE POSSIBLE MONDAY EVENING AND MONDAY NIGHT...AND CARRYING VICINITY SHOWERS IN THE AREA TAFS DURING THAT TIME. 19 && .PREV DISCUSSION... /ISSUED 547 PM CST SUN FEB 10 2013/ DISCUSSION... SEE AVIATION SECTION. AVIATION... VFR CONDITIONS WILL PREVAIL AT THE TAF SITES TONIGHT AND MONDAY. SOME INCREASE IN HIGH CLOUD COVERAGE IS EXPECTED TONIGHT. SOME MID-LEVEL CLOUD DEVELOPMENT IS EXPECTED ACROSS SOUTHERN SECTIONS OF WEST CENTRAL TEXAS LATE TONIGHT AND MONDAY. A FEW SPRINKLES OR PERHAPS A LIGHT RAIN SHOWER IS POSSIBLE MONDAY...TO THE EAST OF THE KJCT AND KBBD TERMINALS. WINDS WILL BE LIGHT AND VARIABLE TONIGHT. EAST-SOUTHEAST WINDS WILL DEVELOP ON MONDAY AND INCREASE TO 8-12 KT. 19 PREV DISCUSSION... /ISSUED 349 PM CST SUN FEB 10 2013/ SHORT TERM... RELATIVELY QUIET WEATHER CONDITIONS IN THE SHORT TERM PERIOD. A WEAK FRONT WILL ENTER THE BIG COUNTRY LATE TONIGHT BUT WILL WASH OUT ACROSS THE AREA ON MONDAY. SUBTROPICAL JET WILL CONTINUE TO FEED MID AND HIGH LEVEL MOISTURE FROM THE SOUTHWEST ACROSS MAINLY SOUTHERN SECTIONS OVERNIGHT. THE NAM CONTINUES TO SHOW SOME LIGHT RAIN SHOWERS DEVELOPING OVER EXTREME SOUTHEAST COUNTIES ON MONDAY IN AN AREA OF WEAK ISENTROPIC ASCENT/WAA. 3KM WRF AND LATEST RUC ALSO HINTING AT THIS POSSIBILITY SO WILL KEEP SLIGHT CHANCE POPS INTACT THIS FORECAST CYCLE. CLOUD COVER WILL LIMIT COOLING ACROSS SOUTHEAST SECTIONS TONIGHT WITH LOWS MAINLY IN THE LOWER 40S. LIMITED CLOUD COVER...LIGHT WINDS AND A DRY AIRMASS WILL ALLOW TEMPS TO COOL INTO THE LOW TO MID 30S ACROSS THE REMAINDER OF THE AREA. MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE ON MONDAY WITH AFTERNOON HIGHS RANGING FROM THE LOW TO MID 60S NORTH TO THE MID AND UPPER 60S SOUTH. 24 LONG TERM... UPPER LOW NEAR THE FOUR CORNERS LATE MONDAY WILL WILL DIG SOUTHEAST TUESDAY INTO NEW MEXICO. SURFACE TO 850MB LAYER WILL QUICKLY SATURATE OVER THE ENTIRE CWA BY MIDNIGHT MONDAY CONCOMITANT WITH AN INTENSIFYING LLJ...40-50KT CENTERED OVER THE SOUTHWESTERN CWA. THE HEAVIEST RAINFALL ACCUMULATION CHANCES WILL BE OVER THE BIG COUNTRY ON THE NOSE OF THE LOW LEVEL JET BEGINNING AROUND MIDNIGHT MONDAY AND LASTING INTO TUESDAY MORNING. HAVE INCLUDED THE MENTION OF CONVECTIVE ACTIVITY MONDAY NIGHT THROUGH TUESDAY AS THE COLD FRONT/DRYLINE MOVES EAST THROUGH THE FORECAST AREA. LATEST SPC CONVECTIVE OUTLOOK MENTIONS VIA A SEE TEXT THE POSSIBILITY FOR LARGE HAIL FOR OUR AREA BASED ON SUFFICIENT INSTABILITY AND SHEAR VALUES FOR ELEVATED SUPERCELLS...AS REFLECTED IN THE LATEST FORECAST SOUNDINGS...WILL CONTINUE TO EVALUATE THIS POSSIBILITY. PRECIPITATION CHANCES WILL BE CONFINED TO OUR EASTERN TIER OF COUNTIES BY TUESDAY AFTERNOON WITH PRECIPITATION ENDING OVER ALL OF THE FORECAST AREA BY TUESDAY EVENING. TUESDAY MORNING LOWS WILL RANGE FROM THE LOWER 40S TO AROUND 50 DEGREES AND TUESDAY AFTERNOON HIGHS WILL RANGE FROM THE MID 50S TO THE MID 60S UNDER CLOUDY SKIES. AFTERNOON HIGHS AND MORNING LOWS WILL REMAIN NEAR CLIMO THROUGH THE COMING WEEKEND...GENERALLY IN THE LOWER 60S FOR HIGHS AND THE MID 30S FOR LOWS. THE NEXT COLD FRONTAL PASSAGE WILL BE LATE THURSDAY WITH LITTLE IMPACT ON THE FORECAST AREA. 15 && .PRELIMINARY POINT TEMPS/POPS... ABILENE 33 64 46 58 32 / 0 5 60 40 10 SAN ANGELO 34 70 50 64 35 / 0 10 50 10 5 JUNCTION 43 68 45 66 35 / 0 20 50 20 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1113 PM CST SUN FEB 10 2013 .UPDATE... ALTHOUGH THERE IS DRY AIR IN THE LOWER 8000 FEET OF THE ATMOSPHERE...RADAR RETURNS HAVE INCREASED TO THE POINT WHERE SOME SPRINKLES OR PATCHES OF LIGHT RAIN ARE LIKELY OVERNIGHT ACROSS THE AREA SOUTH OF A COMANCHE TO MCKINNEY TO COOPER LINE. THUS HAVE ADDED A 10 PERCENT CHANCE OF LIGHT RAIN IN THOSE AREAS. 58/91 && .AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH 06Z TUESDAY. LIGHT WEST TO NORTHWEST WINDS THIS EVENING WILL BECOME NORTHEAST AT 5 TO 10 KNOTS BEFORE DAYBREAK AND EASTERLY MONDAY AFTERNOON. THERE WILL BE SOME LOW RAIN CHANCES LATE MONDAY AFTERNOON THROUGH THE EVENING IN THE METROPLEX...BUT THE CHANCES ARE NOT HIGH ENOUGH TO MENTION IN THE TAFS. RAIN CHANCES MONDAY AFTERNOON IN THE WACO AREA MAY PROMPT THE ADDITION OF VCSH WITH THE 03Z UPDATES. RAIN CHANCES WILL IMPROVE AREA WIDE AFTER MIDNIGHT. 58 && .PREV UPDATE... .UPDATE... ONLY SOME MINOR CHANGES NEEDED TO THE CURRENT FORECAST. WATER VAPOR IMAGERY SHOWS THE POWERFUL UPPER STORM THAT BROUGHT LAST NIGHTS WEATHER NOW MOVING INTO THE UPPER MIDWEST. THERE IS ANOTHER UPPER TROUGH OVER THE WESTERN US AND THIS IS HELPING KEEP NORTH TEXAS IN A FAST SOUTHWEST FLOW ALOFT. FORT WORTH RAOB SAMPLED A 150KT UPPER JET AT 230MB. THERE IS SOME MOISTURE ALSO STREAMING OVERHEAD AS INDICATED BY THE PARTIAL CLOUD COVER. FARTHER SOUTH...MOISTURE IS A LITTLE BETTER AND RAP FORECAST SOUNDINGS ACTUALLY INDICATE SOME SATURATION ABOVE 600MB. THIS IS RESULTING IN SOME LIGHT PRECIPITATION ACROSS THE FAR SOUTHERN COUNTIES...HOWEVER GIVEN THE DRY AIR BENEATH IT...MOST OF THE RETURNS ON THE RADAR ARE VIRGA. NOT EXPECTING ANY PRECIP TO REACH THE GROUND OVERNIGHT TONIGHT. BETTER RAIN CHANCES WILL ARRIVE LATE TOMORROW AND PERSIST INTO TUESDAY. CHANGES TO CURRENT FORECAST WERE LIMITED TO HOURLY TEMPERATURES AND SKY COVER. DUNN && .PREV DISCUSSION... /ISSUED 348 PM CST SUN FEB 10 2013/ AFTERNOON WATER VAPOR SATELLITE IMAGERY INDICATED A POWERFUL UPPER LOW OVER THE NORTH PLAINS WITH A STRONG SHORTWAVE TROUGH LOCATED OVER EASTERN NEVADA. AFTERNOON SURFACE OBSERVATIONS SHOWED WESTERLY WINDS OVER ALL OF NORTH AND CENTRAL TX...THE RESULT OF A PACIFIC TYPE COLD FRONT THAT MOVED THROUGH OVERNIGHT AND WAS ACCOMPANIED BY A LINE OF STRONG TO SEVERE THUNDERSTORMS. PERSISTENT WESTERLY FLOW HAS ADVECTED A VERY DRY AIR MASS OVER NORTH TX THIS AFTERNOON WITH DEW POINTS OBSERVED IN THE TEENS WEST OF THE INTERSTATE 35 CORRIDOR AND IN THE UPPER 20S TO LOWER 30S TO THE EAST. PERSISTENT CLOUD COVER HAS HELD TEMPERATURES IN THE MID 60S FOR MOST LOCATIONS...DESPITE THE DRY AIR IN PLACE. TONIGHT THROUGH WEDNESDAY...THE NEVADA SHORTWAVE TROUGH WILL CONTINUE TO SINK SOUTH-SOUTHEAST THROUGH TOMORROW MORNING AS IT MERGES WITH A SECOND...COMPACT AND VERY FAST MOVING...TROUGH COMING OUT OF WESTERN CANADA. AS THIS TROUGH APPROACHES THE REGION IT WILL SPREAD LARGE SCALE FORCING FOR ASCENT OVER THE CWA...RESULTING IN AN INCREASE IN LOW LEVEL CLOUD COVER FROM SOUTHEAST TO NORTHWEST THROUGH MONDAY AFTERNOON. THIS MOISTURE RETURN WILL LIKELY RESULT IN ISOLATED RAIN SHOWERS DEVELOPING ALONG AND SOUTHEAST OF AN ATHENS TO GATESVILLE LINE MONDAY MORNING...SPREADING NORTHWEST TOWARDS THE DFW METROPLEX BY MONDAY AFTERNOON. DUE TO THE VERY DRY AIR CURRENTLY IN PLACE...THINK THAT RAINFALL WILL BE LIGHT IN NATURE...WITH INITIAL RAIN SHOWERS WORKING TO SATURATE THE NEAR SURFACE LAYER FROM THE TOP DOWN RESULTING IN VIRGA AND LOWERING CLOUD DECKS. HIGHS ON MONDAY WILL LIKELY STRUGGLE TO REACH 60 DEGREES FOR THE SOUTHEASTERN PORTIONS OF THE CWA WITH MOSTLY CLOUDY SKIES AND ISOLATED RAIN SHOWERS TO CONTEND WITH. ELSEWHERE HIGHS WILL LIKELY ONLY REACH THE LOWER 60S. ISOLATED RAIN SHOWERS WILL SPREAD NORTH OVER THE ENTIRE CWA MONDAY EVENING AS THE TROUGH BEGINS TO MOVE EAST-NORTHEAST TOWARDS THE SOUTH PLAINS. MOST GUIDANCE BRINGS NUMEROUS RAIN SHOWERS OVER NORTH AND CENTRAL TX LATE MONDAY NIGHT AND INTO TUESDAY MORNING AS THE BEST LARGE SCALE FORCING FOR ASCENT MOVES OVER NORTH TX. DID NOT MAKE ANY REAL CHANGE TO THE PREVIOUS FORECAST DURING THIS PERIOD AS LIKELY /60 TO 70/ POPS SEEM APPROPRIATE FOR THE EXPECTED COVERAGE OF RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING. MAINTAINED THE MENTION OF ISOLATED THUNDERSTORMS EMBEDDED IN THE MORE WIDESPREAD RAIN SHOWER ACTIVITY BECAUSE BOTH THE GFS AND ECMWF INDICATE THAT WE WILL RECEIVE A GOOD INFLUX OF MID TO UPPER LEVEL MOISTURE AS A WEAK SHORTWAVE TROUGH OVER THE OPEN WATERS OF THE PACIFIC IS DRAWN OVER THE REGION DURING THIS TIME. MOST OF THE RICH/TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE WILL BE SCOURED OUT BY THE HIGH TERRAIN OF MEXICO...BUT WHAT REMAINS WILL CERTAINLY HELP SUPPORT WIDESPREAD RAIN SHOWERS MONDAY NIGHT AND TUESDAY MORNING. AS OPPOSED TO OUR LAST SYSTEM...MODELS DO NOT FORECAST STEEP MID-LEVEL LAPSE RATES BEFORE PRECIPITATION BEGINS...SO THINK THAT ANY EMBEDDED THUNDERSTORMS ARE VERY UNLIKELY TO PRODUCE SEVERE WEATHER AT THIS TIME. AS THE WEAK PACIFIC OCEAN ENERGY MOVES EAST OF THE REGION...IT WILL BE REPLACED BY A GOOD MID TO UPPER LEVEL DRY SLOT WORKING IN BEHIND OUR NEVADA SHORTWAVE WHICH IS EXPECTED TO MOVE EAST...RIGHT ALONG THE RED RIVER DURING THE DAY ON TUESDAY. THIS DRY SLOT WILL BRING AND END TO PRECIPITATION OVER THE CWA FROM SOUTHWEST TO NORTHEAST TUESDAY AFTERNOON AS THE DRY SLOT WORKS TO DRY OUT THE ATMOSPHERE FROM THE TOP DOWN. DEPENDING ON THE EXACT TRACK OF THE NEVADA SHORTWAVE TROUGH...WE MAY SEE SOME PRECIPITATION LINGER JUST SOUTH OF THE RED RIVER TUESDAY EVENING AS COLDER AIR BUILDS INTO THE REGION FROM THE NORTHWEST. THE CONSENSUS OF 10/12Z GUIDANCE CONTINUES TO INDICATE THAT THE TROUGH WILL MOVE EAST RIGHT ALONG THE RED RIVER WHICH KEEPS ANY CHANCE OF A CHANGE OVER TO SNOW NORTH OF THE RED RIVER AT THIS TIME. EVEN THE ECMWF...WHICH HAS BEEN MOST AGGRESSIVE WITH COLD AIR ADVECTION ON THE BACK SIDE OF THIS TROUGH...KEEPS TEMPERATURES NEAR THE RED RIVER IN THE UPPER 30S WHILE THERE IS STILL ENOUGH MOISTURE IN PLACE FOR PRECIPITATION TO DEVELOP NEAR THE CWA. AS A RESULT...KEPT A SLIGHT CHANCE FOR RAIN/RAIN SHOWERS IN THE FORECAST NEAR THE RED RIVER THROUGH MIDNIGHT/06Z TUESDAY NIGHT. EXTENDED...COLDER AIR WILL BUILD INTO NORTH AND CENTRAL TX BEHIND THE NEVADA SHORTWAVE TROUGH. HOWEVER PERSISTENT NORTHWEST/WESTERLY FLOW WILL ONCE AGAIN SCOUR LOW LEVEL MOISTURE WELL AWAY FROM THE REGION REDUCING THE CHANCE OF ANY PRECIPITATION THROUGH THE REMINDER OF THE WEEK. WE ARE EXPECTED TO REMAIN IN A SOMEWHAT ACTIVE/FAST FLOW REGIME ALOFT WHICH WILL SEND A COUPLE OF WEAK UPPER LEVEL DISTURBANCES OVER THE CWA FOR THE LATTER HALF OF THE UPCOMING WORK WEEK. NONE OF THESE DISTURBANCES IS PARTICULARLY IMPRESSIVE IN NATURE IN TERMS OF ABILITY TO SPREAD LARGE SCALE FORCING FOR ASCENT OVER THE REGION. WE WILL LIKELY SEE SKIES CLOUD UP AS EACH DISTURBANCE PASSES BY...BUT WITHOUT BETTER MOISTURE TO WORK WITH...THINK THAT CHANCE OF ANY PRECIPITATION WILL REMAIN LOW THROUGH THE END OF THE WEEK. THE ECMWF HAD BEEN DRAGGING A STRONG BUT POSITIVELY TILTED TROUGH OVER THE SOUTH PLAINS AT THE END OF THE WEEK. THIS WOULD HAVE SPREAD MORE PERSISTENT LARGE SCALE FORCING FOR ASCENT OVER THE CWA WHICH MAY HAVE RESULTED IN SOME LIGHT PRECIPITATION...AND POSSIBLY EVEN SOME WINTRY WEATHER. HOWEVER TODAYS 12Z ECMWF IS IN MUCH BETTER AGREEMENT WITH THE GFS WHICH KEEPS A LARGE TROUGH OVER THE NORTHEASTERN CONUS...WITH ONLY TRANSIENT/WEAK DISTURBANCES PROVIDING LIFT OVER THE CWA THROUGH NEXT WEEKEND. AS A RESULT MAINTAINED A DRY FORECAST THROUGH NEXT WEEKEND...WITH TEMPERATURES HOLDING NEAR OR MAYBE SLIGHTLY BELOW SEASONAL NORMALS AS EACH UPPER DISTURBANCE SENDS A REINFORCING SHOT OF COOL AIR INTO NORTH AND CENTRAL TX. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 42 60 45 54 38 / 10 10 50 70 10 WACO, TX 44 62 48 63 40 / 10 20 50 50 10 PARIS, TX 39 60 42 46 38 / 5 10 30 70 20 DENTON, TX 40 61 44 49 36 / 5 10 50 70 20 MCKINNEY, TX 40 61 44 49 37 / 5 10 50 70 20 DALLAS, TX 42 60 46 55 39 / 10 10 50 70 10 TERRELL, TX 42 60 45 55 39 / 10 20 40 70 10 CORSICANA, TX 46 58 47 59 41 / 10 20 40 60 10 TEMPLE, TX 47 63 49 65 40 / 10 30 50 50 10 MINERAL WELLS, TX 37 62 44 56 35 / 5 10 60 50 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 58/91
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1235 AM EST MON FEB 11 2013 .SYNOPSIS... A WARM FRONT WILL LIFT NORTHEAST ACROSS THE REGION LATER TONIGHT FOLLOWED BY A TRAILING COLD FRONT THAT WILL SWEEP EAST THROUGH THE AREA MONDAY. ANOTHER STORM SYSTEM LOOKS TO MOVE NORTHEAST ACROSS THE EASTERN CAROLINAS ON WEDNESDAY...POSSIBLY RESULTING IN THE NEXT ROUND OF WINTRY WEATHER FOR MIDWEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 930 PM EST SUNDAY... WELL...BAND OF SLEET/SOME SNOW AND RAIN MOVED IN CAUSING SOME MINOR TRAVEL ISSUES. THE DUAL POL HAS DONE AN EXCELLENT JOB OF DEPICTING THIS. CURRENTLY...SOME SLEET STILL BEING OBSERVED OVER THE ROANOKE VALLEY. RADAR INDICATES POCKETS OF SLEET AND GIVEN THE DRY AIRMASS...SHOULD SEE THINGS WET BULB ENOUGH TO BRING SLEET TO THE PIEDMONT BUT NO ACCUMULATION HERE GIVEN WARMER TEMPS. OVER THE ALLEGHANY HIGHLANDS OF BATH INTO PORTIONS OF GREENBRIER COULD SEE A FEW TENTHS OF AN INCH OF SNOW/SLEET. THE LATEST RUC HAD THIS NAILED AS FAR AS HAVING A NARROW BAND OF PRECIP AND DRYING IT OUT TO THE WEST. HAVE SINCE FOLLOWED THIS MODEL UNTIL DAWN...BUT LEFT ROOM IN FOR DEVELOPMENT OF LIGHT PRECIP IN THE WEST...BUT ONLY SLIGHT TO LOW CHANCE. MOST AREAS OVERNIGHT WILL BE DRY. WARM FRONT EDGES NWD...BUT IN-SITU WEDGE WILL HOLD AT LEAST UNTIL MID MORNING MONDAY BEFORE THE COLD FRONT ARRIVES. WILL KEEP IT CLOUDY ALL NIGHT. RUC DOES SHOW SOME HIGHER OMEGA RETURNING OVER THE SOUTHERN CWA OVERNIGHT SO KEPT POPS HIGHER HERE. SO IN SUMMARY CUT POPS BACK FROM EARLIER FORECAST. TEMPS COOL SOME WITH PRECIP BUT THERE IS MORE OF AN INCREASE IN THE DEWPOINTS. THINK TEMPS STAY STEADY IN THE WEDGE OR SLOWLY FALL WHILE STEADY OR SLOWLY RISING TEMPS OCCUR OVER THE FAR SW OUTSIDE THE WEDGE BARRING ANY PRECIP. THE WINDS WILL BE STRONGEST BETWEEN THIS AFD AND ABOUT 08Z...WHEN SFC WINDS TURN MORE SSW. COULD BE A FEW GUST ON THE HIGHER RIDGES LIKE MT ROGERS OVER 50 KNOTS...BUT ISOLATED NATURE AND WILL NOT UPGRADE TO HIGH WIND WARNING. PREVIOUS VALID DISCUSSION... A COLD FRONT WILL SWEEP EAST MONDAY. MOST OF THE RAIN WILL END BY MID MORNING MONDAY. IT SHOULD BE WINDY MONDAY WITH DEEP MIXING TO JUST ABOVE H8 AND A WESTERLY DOWNSLOPING FLOW. WIND SPEEDS WILL BE NEAR ADVISORY CRITERIA LEVELS WITH WIND GUSTS ACROSS NORTHWEST NORTH CAROLINA AND INTO THE NEW RIVER VALLEY. HIGHS MONDAY WILL BE MILD WITH READINGS FROM THE LOWER 50S IN THE NORTHWEST TO THE MID 60S IN THE SOUTHEAST. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AS OF 345 PM EST SUNDAY... MONDAY NIGHT THROUGH WEDNESDAY NIGHT... MOISTURE BELOW 850 MB IN SOUTHEAST WEST VIRGINIA ALTHOUGH MODELS NOT PRINTING OUT ANY PRECIPITATION. WINDS REMAIN GUSTY UNTIL TUESDAY MORNING. WINDS AND CLOUDS DIMINISH TUESDAY AFTERNOON AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA. HAVE A LIMITED AMOUNT OF SNOW SHOWERS IN WESTERN GREENBRIER COUNTY...BUT CLOUDS WILL HOLD IN LONGER THROUGH THE MORNING IN THE FAVORED UPSLOPE AREAS. NEXT SYSTEM REMAINS COMPLEX. STILL MODEL DIFFERENCES IN TIMING AND EVEN MORE SO IN TEMPERATURE PROFILE. EXPECT BULK OF THE PRECIPITATION BETWEEN 12Z/7AM WEDNESDAY AND 06Z/1AM THURSDAY. TYPE AND AMOUNT OF PRECIPITATION WILL BE A CHALLENGE. NAM BUFKIT WAS SHOWING COLDER TEMPERATURE PROFILES THEN GFS BUFKIT. BEST LOOKING PART OF THE STORM AT THIS POINT IS THE ISENTROPIC LIFT AND UPSLOPE. WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 230 PM EST SUNDAY... FROM THURSDAY THROUGH SUNDAY...A LONGWAVE TROUGH IS PROGGED TO BE OVER THE JAMES BAY REGION OF CANADA AND SOUTH INTO THE EASTERN U.S. THAT IS ONE ELEMENT OF THIS PORTION OF THE FORECAST THAT HAS MODERATELY HIGH CONFIDENCE. ANOTHER ELEMENT WITH MODEATELY HIGH CONFIDENCE IS THE TEMPERATURE FORECAST...AT LEAST THE TREND. PROGRESSIVELY COLDER AIR WILL BE ENTERING THE REGION ON GUSTY NORTHWEST WINDS...ESPECIALLY BY THE START OF NEXT WEEKEND. THERE IS LOW CONFIDENCE CONCERNING THE SPEED AND TRACK OF INDIVIDUAL SHORTWAVE TROUGHS WITHIN THE LARGER LONGWAVE TROUGH PATTERN. GUIDANCE COMPARED TO YESTERDAY...AND COMPARED TO EACH OTHER WITH THE LATEST 12Z...7AM...MODELS...OFFER DIFFERENT SOLUTIONS AND EACH WOULD IMPACT THE WEATHER ACROSS OUR REGION IN VARIOUS WAYS. GOING TO LEAN TOWARDS A DRIER...BUT COMPARABLE...SOLUTIION TO THAT OFFERED FOR THIS TIME PERIOD BY HPC. GIVEN THIS...OUR FORECAST WILL REFLECT ONE THAT WILL HAVE PROGRESSIVELY COLDER TEMPERATURES. HIGHS ON THURSDAY WILL BE ROUGHLY 10 TO 15 DEGREE WARMER THAN THOSE EXPECTED ON SUNDAY. LIKEWISE...LOWS ON THURSDAY NIGHT WILL BE ROUGHLY 10 DEGREES MILDER THAN THOSE EXPECTED SATURDAY NIGHT. WE WILL HAVE UPSLOPE RAN/SNOW SHOWERS FORECAST IN SOUTHEAST WEST VIRGINIA AND NEIGHBORING PORTIONS OF SOUTHWEST VIRGINIA THURSDAY NIGHT AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH OHIO VALLEY. BETTER COVERAGE OF PRECIPITATION IS FORECAST SATURDAY AND SATURDAY NIGHT AHEAD OF..AND DURING THE PASSAGE OF A SLIGHTLY MORE ROBUST SHORTWAVE TROUGH THAT WILL HAVE ITS ORIGINS FROM THE CENTRAL PLAINS...AND GET AMPLYFIED AS IT INTERACTS WITH THE EASTERN LONGWAVE TROUGH. BEHIND THIS SYSTEM...UPSLOPE SNOW SHOWERS ARE EXPECTED OVER SOUTHEAST WEST VIRGINIA DURING THE DAY SUNDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 12120 AM EST MONDAY... INITIAL BATCH OF FAST MOVING PRECIP HAS QUICKLY EXITED TO THE EAST LEAVING SOME LEFTOVER PATCHY -RA/-DZ IN SPOTS MAINLY OVER THE WEST. EXPECT MAY SEE SOME ADDED RAIN FILL BACK IN AHEAD OF THE WARM FRONT BACK OVER TN THROUGH DAYBREAK...OTRW THINKING CIGS WILL LOWER FROM CURRENT MVFR/VFR LEVELS TO IFR MOST SPOTS AS THE WARMER AIR ALOFT WORKS OVERTOP THE LINGERING LOW LEVEL WEDGE. HOWEVER CONFIDENCE RATHER LOW GIVEN MODEL UNCERTAINTY AS DEVELOPMENT OF MORE RAIN TO THE SW COULD ACTUALLY KEEP CIGS HIGHER VS THE LOWER DRIZZLE/STRATUS SCENARIO. LOW LEVEL WIND SHEAR WILL REMAIN A PROBLEM AT MOST LOCATIONS DURING THE OVERNIGHT WITH STRONG SFC WINDS THE MAIN CONCERN AT KBLF WHERE COULD GUST TO 35 KTS OVER THE NEXT FEW HOURS. THE LOW LVL WIND SHEAR STARTS TO GO AWAY BY MID MORNING MONDAY AS THE FRONT MOVES ACROSS AND MIXING TAKES PLACE. THE RAIN/DRIZZLE SHOULD ALSO START TO EXIT LEAVING BEHIND LOWER CIGS IN ITS WAKE WITH UPSLOPE SHOWERS OVER SE WV. THE MIXING SHOULD BRING ABOUT SCATTERING OF LOWER CIGS EAST OF THE WV MTNS BY MIDDAY...WITH GUSTY WEST-NW WINDS AT 20 TO 35 KNOTS POSSIBLE. WILL HAVE BLF CLEARING OUT AS WELL AROUND MIDDAY...GIVEN FAST EXIT OF LOW LVL MOISTURE. EXPECT VFR TO THEN LINGER INTO MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE SPILLING IN FROM THE WEST BEFORE WEAKENING TUESDAY EVENING. ANOTHER AREA OF LOW PRESSURE IS THEN EXPECTED TO FORM ON THE RESIDUAL FRONT TO THE SOUTH BY MIDWEEK WITH PERHAPS ANOTHER ROUND OF PRECIP AND LOWER CIGS ON WEDNESDAY. VFR SHOULD AGAIN RETURN TO ALL SITES ON THURSDAY AS WEAK HIGH PRESSURE BUILDS IN BEHIND THE EXITING AREA OF LOW PRESSURE. THE ARRIVAL OF MUCH COLDER AIR BY WEEKS END WILL LIKELY PRODUCE A PERIOD OF UPSLOPE MVFR CLDNS FOR THE SE WVA SITES FRIDAY WITH SCATTERED SNOW SHOWERS POSSIBLE OTRW VFR ELSW. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR VAZ007-009- 010-015. NC...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NCZ001-018. WV...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR WVZ042. && $$ SYNOPSIS...JH/KK NEAR TERM...KK/WP SHORT TERM...AMS/WP LONG TERM...DS AVIATION...JH/KK/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1138 PM CST SUN FEB 10 2013 .SHORT TERM...TONIGHT 829 PM CST SUN FEB 10 2013 WIND ADVISORY TO BE ISSUED SHORTLY...SEE DETAILS BELOW. THE CORE OF A LOW PRESSURE SYSTEM IS CURRENTLY JUST TO THE WEST OF THE FORECAST AREA ALONG THE I-35 CORRIDOR IN SOUTH CENTRAL MINNESOTA. EAST OF THIS LOW...A WARM FRONT EXTENDS TO THE WEST INTO WESTERN WISCONSIN WITH WIDESPREAD RAIN AND DRIZZLE OCCURRING ALONG AND TO THE SOUTH OF IT. SOME FOG STILL REMAINS ALONG AND NORTH OF THIS FRONT...BUT VISIBILITY HAS NOT BEEN BELOW A MILE IN THIS REGION...SO WILL BE DROPPING THE FOG FROM THE FORECAST. BASED ON RADAR AND THE LATEST OBSERVATIONS...IT APPEARS THAT THE BACK EDGE OF THE RAIN/DRIZZLE IS RAPIDLY MOVING TO THE NORTHEAST ACROSS NORTHEAST IOWA. EXPECT THAT AS THIS BACK EDGE MOVES THROUGH THAT THERE WILL BE A PERIOD OF DRY CONDITIONS THIS EVENING AND OVERNIGHT. FURTHER TO THE WEST...MAINLY ALONG AND SOUTH OF THE SURFACE LOW...PRECIPITATION HAS CHANGED OVER TO SNOW ALONG THE I-35 CORRIDOR WHERE 11.00Z RAP/LAPS SOUNDINGS INDICATE THAT THE THERMAL PROFILE HAS COOLED TO ALL BEING BELOW FREEZING. DODGE COUNTY AND PORTIONS OF SOUTHEAST MINNESOTA MAY GET CLIPPED BY SOME OF THIS SNOW...BUT IT APPEARS TO MAINLY BE PROPAGATING TO THE NORTHEAST AND SHOULD NOT DROP MUCH ACROSS THIS REGION. AS THE LOW MOVES OFF TO THE NORTHEAST...THE COLD FRONT THAT CURRENTLY EXTENDS TO THE SOUTHEAST OF IT INTO WESTERN IOWA WILL SWING THROUGH THE REGION AROUND AND SHORTLY AFTER MIDNIGHT. SNOW SHOWERS WILL MOVE IN AFTER THE FRONT PASSES THOUGH THEY WILL NOT BE VERY INTENSE. VISIBILITIES HAVE MAINLY BEEN IN THE 1-3SM RANGE AND THAT IS EXPECTED TO BE THE LOW END OF WHAT WE WILL SEE AS IT MOVES INTO THE REGION OVERNIGHT INTO TOMORROW. THE TIGHTENING SURFACE PRESSURE GRADIENT WILL ALSO TRACK TO THE NORTHEAST WITH THE LOW MOVING IN THAT DIRECTION. THE CORE OF THESE STRONG WINDS WILL EXTEND ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA AND SOUTHWEST WISCONSIN...PARTICULARLY IN THE HIGHER ELEVATIONS. 11.00Z AND PREVIOUS RAP BUFKIT SOUNDINGS SHOW THAT WIND GUSTS SHOULD BE AROUND 45 MPH AT TIMES...PARTICULARLY TOMORROW MORNING AFTER SUNRISE. WILL BE ISSUING A WIND ADVISORY STARTING AT MIDNIGHT AND RUNNING IT INTO 3PM TOMORROW AFTERNOON WHEN IT APPEARS THAT THE WINDS WILL WEAKEN ALONG WITH THE PRESSURE GRADIENT. THE LOBE OF STRONGEST WINDS WILL START OUT IN THE SOUTH AND WORK THEIR WAY NORTHWARD AFTER MIDNIGHT...SO SOME LOCATIONS IN THE ADVISORY MAY BE A LITTLE DELAYED IN GETTING THE STRONGEST WINDS COMPARED TO THAT AREA. .LONG TERM...WEDNESDAY THROUGH SUNDAY 256 PM CST SUN FEB 10 2013 NORTHWEST FLOW ALOFT WILL SET UP OVER THE UPPER MIDWEST IN THE WAKE OF THE CURRENT STORM SYSTEM. THIS WILL ALLOW A SYSTEM TO DROP INTO THE REGION FOR THE MIDDLE OR END OF THE WEEK. THE MODELS SHOW VERY LITTLE CONSISTENCY ON THE TIMING OF THIS FEATURE. THE 10.12Z GFS IS THE FASTEST BRINGING IN WEDNESDAY AFTERNOON WHILE THE 10.12Z GEM IS THE SLOWEST AND STRONGEST AND DOES NOT BRING IT IN UNTIL THURSDAY NIGHT. UNTIL THESE TIMING DIFFERENCES ARE WORKED OUT...WILL NEED TO CARRY A MENTION OF PRECIPITATION FROM WEDNESDAY NIGHT THROUGH FRIDAY WITH THE BEST CHANCES CENTERED ON WEDNESDAY NIGHT AND THURSDAY. THE SURFACE LOW MAY PASS BY JUST TO THE NORTH OF THE AREA THURSDAY BRINGING ENOUGH WARM AIR FOR A MIX OF RAIN AND SNOW ACROSS THE SOUTH WITH LIGHT SNOW EXPECTED ELSEWHERE. && .AVIATION...THROUGH 06Z TUESDAY 1138 PM CST SUN FEB 10 2013 PRECIPITATION IS CHANGING OVER TO SNOW AS A COLD FRONT APPROACHES THE REGION. CONDITIONS ARE EXPECTED TO BE MAINLY AT IFR OR LOWER THROUGHOUT THE REGION THOUGH LSE HAS BEEN AT LOW END MVFR WITH A 1100FT CEILING. CEILINGS WILL LIKELY BE MORE STABLE THAN WHAT VISIBILITIES ARE AS THE SNOW IS FAIRLY VARIABLE WITH CONDITIONS RANGING FROM 6SM DOWN TO 1 1/2SM AT TIMES AS THE SNOW SHOWERS COMES THROUGH. EXPECT THAT THIS WILL BE THE CASE THROUGH MUCH OF THE MORNING AND EARLY AFTERNOON HOURS BEFORE THE FORCING WEAKENS LATE IN THE AFTERNOON. WINDS WILL INCREASE AS THE COLD FRONT MOVES THROUGH THE REGION TONIGHT WITH SUSTAINED WINDS AROUND 20 TO 25KTS WITH GUSTS UP TO 35-37KTS AT TIMES. THESE WEST TO NORTHWEST WINDS WILL DIMINISH IN SPEED LATE IN THE AFTERNOON AND EVENING HOURS AS THE SURFACE LOW ASSOCIATED WITH THIS SYSTEM TRACKS FURTHER TO THE NORTHEAST. && .ARX WATCHES/WARNINGS/ADVISORIES... 829 PM CST SUN FEB 10 2013 WI...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR WIZ032>034-041>044-053>055-061. MN...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR MNZ079-086>088-094>096. IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR IAZ008>011-018-019-029-030. && $$ SHORT TERM...HALBACH LONG TERM...04 AVIATION...HALBACH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1030 PM CST SUN FEB 10 2013 .UPDATE... ISSUED A WIND ADVISORY FOR THE ENTIRE CWA FOR OVERNIGHT INTO MONDAY. POINTS AGAINST ISSUING WITH AN 06Z START TIME ARE: THE INVERSION OVER THE SNOW-PACK PREVENTING FULL MOMENTUM TRANSFER TO THE SURFACE TONIGHT. USUAL DIFFICULTY IN GETTING SUSTAINED 30 MPH WINDS WITH THE ROUGH TERRAIN...TREES...HILLS...ETC. POINTS FOR ARE THE 40 TO 44 KNOT WINDS JUST OFF THE SURFACE ABOVE A WEAK NEAR-SURFACE INVERSION. ONCE COLD AIR ADVECTION BEGINS WITH 4 TO 6 MB PER 3 HOUR SURFACE PRESSURE RISES...THIS INVERSION DISAPPEARS AND THERE IS A GOOD POTENTIAL OF A 40 KNOT GUST TO REACH THE SURFACE. 36KT GUST AT MONROE REPORTED AT 0335Z SHOWS HOW EASILY AN ADVISORY LEVEL GUST COULD REACH THE SURFACE. REALIZE IT WILL BE MARGINAL OVER THE NORTHEAST AS GRADIENT WONT BE AS TIGHT UNTIL LATER IN THE OVERNIGHT...BUT NEW NAM FORECAST SOUNDINGS FOR SHEBOYGAN IN LINE WITH RAP SHOWING MIXING UP TO 40-41 KTS BY 08Z...SO AN ISOLATED ADVISORY LEVEL GUST NOT OUT OF THE QUESTION. BETTER CHANCE FOR WIDESPREAD ADVISORY CONDITIONS MONDAY...WITH MIXING UP TO 875 MB AND WEST TO NORTHWEST WINDS AROUND 40 KTS. && .AVIATION/06Z TAFS/... WILL TAKE OUT LOW-LEVEL WIND SHEAR AS DIFFERENTIAL DECREASES WITH INCREASING SURFACE WIND GUSTS. VFR CONDITIONS OVER THE FORECAST AREA ARE TEMPORARY AND WILL DROP BACK TO MVFR BY ISSUANCE TIME. WIND GUSTS WILL BE THE MAIN ISSUE AS SOUTHWEST WINDS WILL INCREASE TO 20 TO 25 KT SUSTAINED...WITH GUSTS OF 30 TO 40 KTS...BECOMING WEST IN THE MORNING WITH GUSTS TO 45 KNOTS BY LATE IN THE MORNING INTO THE AFTERNOON. WINDS WILL SLOWLY DECREASE FROM SOUTHWEST TO NORTHEAST DURING THE AFTERNOON AND EVENING...BUT ENOUGH GRADIENT FOR GUSTS TO AT LEAST 20 KNOTS AT KMSN AND KUES THROUGH 06Z TUESDAY...AND AROUND 25 KNOTS AT KENW AND KMKE. WILL SEE LAST BAND OF LIQUID PCPN PUSH OUT OVER LAKE MICHIGAN AROUND/SHORTLY AFTER 06Z...WITH POCKETS OF LIGHT SNOW SHOWERS OR FLURRIES ROTATING THROUGH THE FORECAST AREA OVERNIGHT AND MONDAY WITH VORTICITY MAXIMA SPINNING AROUND CLOSED 500 MB LOW. WILL KEEP MVFR CIGS THROUGH THE REMAINDER OF THE FORECAST...THOUGH SOME IFR POSSIBLE IN THE SNOW SHOWERS. && .MARINE... ADJUSTED START TIME OF GALE WARNING TO 06Z...THOUGH FREQUENT GALE GUSTS BECOME MORE LIKELY CLOSER TO 08Z...THE POTENTIAL FOR GALE GUSTS WITH THE EARLY WIND GUST TO 35 KNOTS AT MONROE AND COLLABORATION SUPPORTED THE 06Z START. WILL NEED A SMALL CRAFT ADVISORY AFTER GALE WARNING EXPIRES...THOUGH LATEST DATA SUGGESTS GALE WARNING MAY NEED AND EXTENSION OVER THE THE NORTHERN ZONES. WAVES WILL BEGIN TO SUBSIDE MONDAY MORNING WITH REDUCED FETCH AS WINDS TURN WEST. && .PREV DISCUSSION... /ISSUED 340 PM CST SUN FEB 10 2013/ VERY SHORT TERM...TONIGHT AND MONDAY. RAIN WILL WIND DOWN THROUGH LATE AFTERNOON. COULD SEE A QUICK ROUND OF SHOWERS SLIDE THROUGH EARLY EVENING WITH SHORTWAVE. OTHERWISE...WILL SEE SOME DRIZZLE AND FOG AT TIMES THROUGH LATE EVENING. COLD FRONT WILL HEAD THROUGH THE FORECAST AREA LATE EVENING INTO TONIGHT...WITH SNOW SHOWERS LIKELY DEVELOPING BEHIND THE FRONT. BEST CHANCE FOR SNOW SHOWERS LOOKS TO BE LATE TONIGHT THROUGH TOMORROW MORNING AS MAIN SHORTWAVE PUSHES THROUGH. EXPECTING MOST EVERYWHERE SHOULD SEE SHOW SHOWERS...WITH A DUSTING TO A COUPLE TENTHS OF AN INCH POSSIBLE...THE HIGHEST AMOUNTS ACROSS THE NORTHERN FORECAST AREA. SNOW SHOWERS WILL LIKELY WIND DOWN TOMORROW AFTERNOON. OTHER THING OF NOTE WILL BE INCREASING WINDS BEHIND THE COLD FRONT LATE TONIGHT INTO MONDAY. GUSTS OF 35 TO 40 MPH EXPECTED MOST PLACES FROM MID MORNING MONDAY THROUGH MUCH OF THE DAYTIME HOURS. HIGHEST GUSTS WILL BE IN THE SOUTHEAST WHERE THEY COULD APPROACH WIND ADVISORY LEVELS OF 45 MPH. SHORT TERM...MONDAY NIGHT THROUGH WEDNESDAY. UPPER LOW PULLS AWAY FROM THE WESTERN GREAT LAKES A BIT FASTER LATER MONDAY AND MONDAY NIGHT AS MID LEVELS RAPIDLY DRY. HENCE WL LOWER POPS BUT STILL MAY BE ABLE TO SQUEEZE OUT SOME EVENING FLURRIES FROM LINGERING LOW LEVEL RH AND CYCLONIC CURVATURE. OTHERWISE A DRY PERIOD CAN BE EXPECTED AS SOUTHERN WISCONSIN REMAINS IN DRIER WEST-NORTHWEST FLOW WITH PASSING WEAK HIGH PRESSURE ON TUESDAY AND WEDNESDAY. SPLIT CONTINUES THROUGH THIS PERIOD WITH SOUTHERN STREAM REMAINING ACTIVE OVER SOUTHERN CONUS. VERY WEAK RIPPLES CAUGHT IN THE FAST FLOW MAY BRING SEVERAL PERIODS OF CLOUDS TO THE AREA ON TUE AND WED. HOWEVER TEMPERATURES SHOULD AVERAGE CLOSE TO SEASONAL NORMAL. LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY. INCREASINGLY HIGHER AMPLITUDE UPSTREAM RIDGE OVER THE EASTERN PACIFIC RESULTS IN DEEPING LONG WAVE TROFING DOWNSTREAM OVER CENTRAL/EASTERN CONUS EARLY IN THE PERIOD. MEDIUM RANGE GUIDANCE GETTING INTO BETTER AGREEMENT ON CLIPPER-TYPE SYSTEM MOVING SOUTHEAST ALONG THE LEADING EDGE OF THE SURGE OF COLDER AIR AND AFFECTING SOUTHERN WI PERHAPS AS EARLY AS WEDNESDAY NIGHT. HENCE CONFIDENCE INCREASING ON A PERIOD OF -SN AFFECTING SOUTHERN WI AROUND THURSDAY WITH ACCUMULATIONS. CIPS 24 HOUR ANALOGS CENTERED AT 00Z/15 HAS A LOW PROBABILITY OF SNOWFALL EXCEEDING 2 INCHES AT THIS TIME. CONSIDERING THIS WAVE IS TRAVELING ALONG A TIGHTENING BAROCLINIC ZONE...WOULD NOT BE SURPRISED IF FUTURE GUIDANCE SHOWS FURTHER STRENGTHENING OF THIS SYSTEM. WILL TREND UPWARD IN POPS FOR THU AND SURROUNDING PERIODS. ENSEMBLE MEMBERS COMING INTO BETTER AGREEMENT AS WELL ON DEEPENING SHORT WAVE TROUGH OVER WESTERN GTLAKES ON THU. COLDER AIR THEN EXPECTED TO SETTLE OVER THE REGION ON FRIDAY AND LINGER THROUGH THE WEEKEND. BOTH UKMO AND ECMWF INDICATING ANOTHER CLIPPER SYSTEM SLIDING SOUTHEAST ACROSS THE UPPER MIDWEST AND POSSIBLY AFFECTING PORTIONS OF WI OVER THE WEEKEND. HOWEVER CONFIDENCE IN THIS LAST SYSTEM REMAINS LOW. AVIATION /00Z TAFS/... RAIN WILL WIND DOWN THROUGH LATE AFTERNOON. COULD SEE A QUICK ROUND OF SHOWERS SLIDE THROUGH EARLY EVENING WITH SHORTWAVE. OTHERWISE...WILL SEE SOME DRIZZLE AND FOG AT TIMES THROUGH LATE EVENING. CIGS AND VSBYS WILL STAY ON THE LOW SIDE THROUGH THE EVENING AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL HEAD THROUGH THE FORECAST AREA LATE EVENING INTO TONIGHT...WITH SNOW SHOWERS LIKELY DEVELOPING BEHIND THE FRONT. BEST CHANCE FOR SNOW SHOWERS LOOKS TO BE LATE TONIGHT THROUGH TOMORROW MORNING AS MAIN SHORTWAVE PUSHES THROUGH. EXPECTING MOST EVERYWHERE SHOULD SEE SHOW SHOWERS...WITH A DUSTING TO A COUPLE TENTHS OF AN INCH POSSIBLE...THE HIGHEST AMOUNTS ACROSS THE NORTHERN FORECAST AREA. SNOW SHOWERS WILL LIKELY WIND DOWN TOMORROW AFTERNOON. VSBYS WILL IMPROVE OVERALL AS THE COLDER AIR FILTERS IN...THOUGH TEMPORARY LOWER VSBYS POSSIBLE IN ANY SNOW SHOWERS. CIGS WILL IMPROVE ALSO...THOUGH LIKELY REMAINING MVFR THROUGH THE DAY MONDAY. MARINE... UPGRADED THE GALE WATCH TO A WARNING...STARTING IT VERY LATE TONIGHT AND RUNNING THROUGH THE DAY MONDAY. SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL THE GALE WARNING GOES INTO EFFECT. LOOKS LIKE A GOOD SHOT FOR GUSTS OF 35 KNOTS DURING THE WARNING PERIOD...POSSIBLY AS HIGH AS 40 KNOTS. WAVES WILL STAY HIGH INTO TONIGHT...SLOWLY SUBSIDING LATE TONIGHT AND MONDAY AS WINDS BECOME OFFSHORE. MAY NEED A SMALL CRAFT ADVISORY FOR AT LEAST MONDAY EVENING AFTER THE GALE ENDS...AS WINDS WILL SLOWLY EASE THROUGH THE EVENING AND OVERNIGHT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WIND ADVISORY UNTIL 3 PM CST MONDAY FOR WIZ046-047-051-052- 056>060-062>072. LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LMZ643>646. GALE WARNING UNTIL 6 PM CST MONDAY FOR LMZ643>646. && $$ UPDATE...REM TONIGHT/MONDAY AND AVIATION/MARINE...DDV MONDAY NIGHT THROUGH SUNDAY...MBK
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
607 AM MST MON FEB 11 2013 .UPDATE... ISSUED AT 602 AM MST MON FEB 11 2013 NICELY WOUND UP LOW/VORTICITY CENTER HAS STARTED TO SHEER APART PER LATEST SATELLITE IMAGERY AND SHOWING SIGNS OF THIS ON LATEST RADAR RETURNS AS WELL. LATEST 3KM HRRR REFLECTIVITY FORECAST GRABBING ONTO THIS AND INDICATING THE EARLIER BAND OF HEAVIER SNOWFALL RESPONSIBLE FOR 2 INCHES OF SNOW IN THE GRAND VALLEY AND NUCLA REGIONS WILL BE TRENDING DOWN...WITH SNOW SHOWERS BECOMING MORE SCATTERED IN NATURE FOR AREAS ALONG AND NORTH OF INTERSTATE 70. AS A RESULT...HAVE WENT AHEAD AND ALLOWED THE WINTER STORM WARNINGS EXPIRE FOR THESE AREAS AS OF 6 AM MST. STILL SHOULD SEE ANOTHER INCH OR TWO IN A FEW AREAS...BUT OVERALL COVERAGE WILL BE DIMINISHED. AWAITING SUNRISE BEFORE MAKING FINAL CALL ON OTHER HIGHLIGHTS...ALTHOUGH IR IMAGERY SUGGESTS WE MAY BE MAKING MORE ADJUSTMENTS TO SOUTHERN HIGHLIGHTS AS THE DAY WEARS ON. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 326 AM MST MON FEB 11 2013 MESSY FORECAST SITUATION THIS WITH QUICKLY CHANGING CONDITIONS ACROSS THE REGION. THE 700-600MB LOW...THAT IS KEY TO THE HIGHLIGHTS IN THE FOUR CORNERS ZONES...WAS PROGGED DIFFERENTLY TONIGHT. IT IS SITUATED FURTHER NORTH THAN PREVIOUSLY PROGGED. IT SPUN NEAR CANYONLANDS NATIONAL PARK THROUGH MUCH OF THE NIGHT AND WILL PROGRESS SOUTH OF THE I-70 CORRIDOR TODAY. ON THE WEST EDGE OF THE ASSOCIATED BAROCLINIC LEAF...VERY HEAVY SNOW BANDS HAVE FORMED. IN NUCLA AND GRAND JUNCTION TWO INCHES FELL IN JUST OVER ONE HOUR WITH VISIBILITY DOWN TO 1/4 MILE. THIS AREA OF HEAVY SNOW WILL MARCH EAST DOWN THE I-70 CORRIDOR THIS MORNING REACHING RIFLE AROUND 5 AM... GLENWOOD SPRINGS TO ASPEN AROUND 7 AM AND EAGLE AROUND 8 AM. ENHANCED CLOUD TOPS ARE SPREADING BACK ACROSS THE NW COLORADO ZONES WHERE LIGHT SNOWFALL WILL CONTINUE THIS MORNING. HIGHLIGHTS WILL LIKELY COME DOWN AT 6 AM AS CURRENTLY TIMED BUT ANOTHER 2-4 INCHES MAY FALL IN THE NORTHERN MTNS TODAY. FURTHER SOUTH...TIGHT LOW LEVEL CYCLONIC ROTATION AND FAVORABLE SOUTHWEST FLOW OROGRAPHICS WILL CONTINUE TO PRODUCE ACCUMULATING SNOW FOR SOUTHEAST UTAH AND SOUTHWEST COLORADO. SNOW AMOUNTS THERE WILL LIKELY BE CLOSER TO 3-6 INCHES IN CEZ-DRO-PSO VALLEYS. THE MID LEVEL LOW SHIFTS EAST OF THE CONTINENTAL DIVIDE LATE THIS AFTERNOON AND THE LAST SNOW SHOWERS OF THIS STORM END BY MIDNIGHT. A COLD NIGHT EXPECTED MONDAY NIGHT UNDER CLEARING SKIES...LIGHT NORTH WINDS...AND 700MB TEMPS AT -14C. AREAS OF FREEZING FOG ARE POSSIBLE. TUESDAY...A TRANSIENT RIDGE PASSES FROM NORTH TO SOUTH PRODUCING WARM ADVECTION ALOFT AND CAPPED VALLEYS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 326 AM MST MON FEB 11 2013 DIRTY NORTH TO NORTHWEST FLOW ALOFT WILL BE SETTING UP OVER THE FORECAST AREA TUESDAY NIGHT AND PERSIST THROUGH THE END OF THE WEEK. THIS WILL BRING A FEW ROUNDS OF SNOW TO THE NORTHERN AND CENTRAL MOUNTAINS...GENERALLY FROM VAIL PASS NORTHWARD...AS WEAK WAVES PUSH THROUGH. THE STRONGEST IN THIS SERIES ARRIVES WEDNESDAY NIGHT AND THURSDAY...AND HAVE BOOSTED POPS UP INTO THE LOW LIKELY CATEGORIES FOR THE FLAT TOPS AND THE PARK RANGE. THIS WAVE WILL DRIVE THE MOISTURE A BIT FURTHER SOUTH...IMPACTING THE SAN JUANS AS WELL...BUT MODELS HAVE BEEN TRENDING WEAKER WITH EACH RUN...SO WILL NOT JUMP POPS UP MUCH AT THIS TIME. HEIGHTS START CLIMBING BY FRIDAY AFTERNOON...WITH DRY CONDITIONS EXPECTED AS WE WORK INTO THE WEEKEND. TEMPERATURES WILL BE RUNNING COOLER THAN NORMAL THIS WEEK...WITH GRADUAL WARMING INTO THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 326 AM MST MON FEB 11 2013 ACROSS THE NORTH INCLUDING KVEL KCAG KHDN KSBS SCATTERED SNOW SHOWERS WILL PRODUCE BRIEF MVFR CEILINGS THROUGH 21Z. OTHERWISE VFR CONDITIONS WILL DOMINATE. WIDESPREAD FOG MAY PERSIST IN THE VCNTY OF KVEL UNTIL 18Z. AND VALLEY FOG IS POSSIBLE AFTER 06Z TONIGHT FURTHER SOUTH SNOW SHOWERS WILL BE WIDESPREAD THROUGH THIS AFTERNOON. MOUNTAIN OBSCURATIONS WITH POOR FLIGHT CONDITIONS WILL BE WIDESPREAD OVER THE SOUTHERN MOUNTAINS AND OCCASIONAL OVER THE CENTRAL MOUNTAINS. LOW CEILINGS WILL PRODUCE MVFR/IFR CONDITIONS AT TIMES OVER THE SOUTHERN AIRPORTS INCLUDING KCEZ KDRO KPSO. THESE TAF SITES MAY BE IMPACTED AT TIMES WITH MVFR AND POSSIBLY EVEN BRIEF IFR CONDITIONS IN SNOW SHOWERS...LOW CLOUDS AND/OR FOG. KRIL KASE KEGE WILL HAVE 1-2 HOURS OF LIFR CONDITIONS IN HEAVY SNOW THIS MORNING BETWEEN 12-15Z. TAF SITES WILL SEE A DECREASING CHANCE OF SNOW THIS AFTERNOON WITH VFR CONDITIONS EXPECTED FOR ALL TAF SITES AFTER 06Z TONIGHT. AREAS OF VALLEY FOG ARE POSSIBLE AFTER 06Z TONIGHT. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ018-019- 021>023. WINTER STORM WARNING UNTIL NOON MST TODAY FOR COZ009-012-017. UT...WINTER STORM WARNING UNTIL NOON MST TODAY FOR UTZ028. WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR UTZ022- 029. && $$ UPDATE...JDC SHORT TERM...JOE LONG TERM...JDC AVIATION...JOE
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
930 AM EST Mon Feb 11 2013 .MESOSCALE UPDATE [through this Afternoon]... Numerous showers and thunderstorms continue to develop along a composite outflow boundary from near the Alabama-Florida border ENE towards Albany, GA (KABY). The outflow boundary roughly establishes the southward extent of a shallow cold pool that developed due to abundant overnight convection. The cold pool appears to be about 2000 feet deep examining the BMX 12z sounding. 13z SPC mesoanalysis (objective RUC analysis) indicates an elongated area of deep moisture convergence along the outflow boundary, with a maximum in west-southwesterly low-level moisture transport centered right over SE Alabama. These moisture transport vectors, and thus the LLJ are close to being boundary-parallel, which from a pattern recognition standpoint is a classic setup for flash flooding. Given recent reports with rainfall totals as high as 8 inches in some of our SE Alabama zones, and the likelihood of additional heavy rainfall through the day, we are becoming increasingly concerned about a significant flash flooding event in those areas. One additional concern is whether or not training echoes will develop south with time - more into the I-10 corridor of the Florida Panhandle. The HRRR supports this idea by afternoon, and therefore the next decision to be made with respect to the Flash Flood Watch will be whether or not to expand it south. Once a decision is made (prior to 1530z) regarding additional expansion of the FFA, we will likely ratchet up the wording in both the existing portion of the FFA (where flooding is already occurring) as well as the HWO. There will still be the potential for isolated severe thunderstorms, as mesoanalysis shows around 1000 j/kg of MLCAPE with around 50 knots of effective shear. However, the best severe weather potential would probably be in the warm sector away from the training storms that are anchored near the outflow boundary. && .NEAR TERM [Tonight]... With front sagging towards N FL tonight and likely stalling, it will be a wet night however there should be a lull in development of storms as we will be in relatively more stable air. may be some fog development ahead of boundary. && .SHORT TERM [Tuesday Through Wednesday]... The large scale long wave pattern commence with a trough over NE states and adjacent Canada with axis down ern seaboard and another trough over Central and srn plains with low developing over TX. Upper high anchored over Srn Gulf of Mex. At surface, low Canadian Maritimes with cold front SSW down extreme wrn Atlc remaining quasi-stnry across fl portion of CWA and into nrn gulf of Mex as it gets caught in the upper level SW flow ahead of upstream trough. With several impulses moving rapidly thru SE region in strong divergent WSW mid/upper flow downstream of upper trough/low, the primary concern will be locally heavy rainfall through the period. During Tuesday, the Ern low will move across New England while Plains low likely opens up into a wave late TUES night. At surface, low forms in Srn Plains and then moves ENE along Nrn Gulf to LA Tues eve then inland to Srn AL at night with cold front lifting NWD back i-10 corridor then to GA/AL border. Initially this translates to increasing overrunning/isentropic lift spreading ewd. As low lifts further newd, front dragged back SEWD across our area. As far as severe wx, best shot will be Tues night. The proximity of the surface low and proximity of front and upper features will favor a strongly sheared environment. Key factor is where front actually sets up. As SPC noted limiting factor may be development of multiple thunderstorm clusters which would retard nwd movement of MT airmass so best chances for strong to severe convection will be near Panhandle coast where dew points in the mid-upper 60s are forecast. North of front, more elevated tstms would favor hail while south of front with strong deep layer shear, more surface based storms with super cells/damaging wind and even an isold tornado cant be discounted. GFS and Nam both show 0-6 KM shear of near 70 kt over SE AL and 60kt over Panhandle at 12z Wed. SPC has placed area in 5% severe prob for Tues night and suspect this will be raised before Tues night. On Wed morning, low across Central GA with cold front bisecting CWA. Several shortwaves move across region to push front SEWD. pops remain especially on high side to begin the day. Chance of strong to isold severe storms remain especially in warm sector where deep shear will battle limited buoyancy for control. By end of period, low races newd, cold front dragged SEWD of CWA with drier air beginning to enter NW third of CWA. Total STP rainfall amounts through Wed could easily average 3 to 4 inches with isolated 5 inches totals especially Nrn tier counties so flooding concerns will be closely monitored. && .LONG TERM [Wednesday Night through Sunday]... The long term forecast is now a little more uncertain due to the slower progression of the upper level system seen in the 12z model cycle. The 00z Euro was weighted heavier in today`s long term forecast, so should the slower progression of the 12z GFS pan out, unsettled weather could continue into Thursday before the Eastern CONUS pattern amplifies enough to kick out the frontal boundary that had been in place across the region. Model guidance, however, is in reasonably good agreement, that with the amplification of the pattern late in the period (Fri-Sun), that cooler than normal weather will be returning to the region. The GFS is much more amplified and colder indicating lows potentially in the low to mid 20s by Sunday morning. Both the 10/00z and 10/12z Euro are less intense with the incoming cooler airmass, so weighted the forecast in this direction, which still produces well below normal temperatures by Sunday. && .AVIATION... [Through 12Z Tuesday] This forecast will be an unsettled one with periods of showers and thunderstorms. These will be most frequent across DHN and ABY, but gradually develop southeast to impact the remaining terminals as a cold front approaches from the northwest. MVFR conditions will prevail for the most part, with periods of IFR early this morning and again overnight. South to southwest winds will be gusty today at all of the terminals with gusts to around 20 kt. Gusts is TS will be higher. Finally, incoming data from the KTAE 12Z upper air sounding indicated 40-kt winds at around 1500 ft and this was supported by the KTLH and KEVX WAD wind profile data. We included a LLWS group at TLH and ECP accordingly. && .MARINE... Based on latest buoys, Small craft advisory will be allowed to drop across the western waters with this package Winds will remain below headline criteria despite occasional storms until Wednesday when an area of low pressure will move across the Gulf. Winds will increase to near advisory levels at this time. Winds will shift to offshore on Thursday and then diminish into the weekend. && .FIRE WEATHER... A cold front will settle south across the forecast area from northwest to southeast today into tonight. This front will then return inland as a warm front on Tuesday as a low pressure system tracks from the north central Gulf of Mexico northeast across the southeastern states. This low will finally drag a stronger cold front across the region on Wednesday. Drier air will arrive behind this front for later in the work week. However, temperatures will also be much cooler which will keep relative humidities above critical values. && .HYDROLOGY... Overnight, some of the flashier rivers across SE AL has shown notable rises and need to be monitored in case a river flood product is necessary later today. Expect 2 to 4 inches of rain across the region starting through Wednesday with the heaviest totals across Southern Alabama and Georgia. Isolated higher totals up to 5 inches are possible. Widespread flooding is not anticipated. However, rises on rivers are anticipated with this rainfall, particularly further to the north where the combination of local runoff and routed upstream flows lead to a few locations reaching minor flood stage later this week. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 77 57 66 58 69 / 70 60 60 80 80 Panama City 74 58 65 57 67 / 80 60 60 90 80 Dothan 73 53 62 55 61 /100 80 80 90 80 Albany 73 52 60 54 67 /100 80 80 90 80 Valdosta 78 54 63 55 69 / 70 60 50 80 70 Cross City 78 57 73 56 72 / 20 40 30 70 70 Apalachicola 72 60 66 60 67 / 60 50 50 80 80 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...FLASH FLOOD WATCH through Tuesday morning for Baker-Calhoun- Clay-Dougherty-Early-Lee-Miller-Quitman-Randolph-Terrell. AL...FLASH FLOOD WATCH through late tonight for Coffee-Dale-Geneva- Henry-Houston. GM...None. && $$ MESOSCALE UPDATE...Lamers NEAR TERM...Wool SHORT TERM...Block LONG TERM...Godsey AVIATION...Wool MARINE...Block FIRE WEATHER...Wool HYDROLOGY...Block
AREA FORECAST DISCUSSION
NWS DES MOINES IA
542 AM CST MON FEB 11 2013 ...UPDATED AVIATION DISCUSSION... .SHORT TERM /TODAY/... MAIN FORECAST CONCERN TODAY IS WITH WINDS...AND LIGHT SNOW SHOWERS/FZDZ ACROSS NORTHERN IOWA. VERTICALLY STACKED LOW WILL CONTINUE TO PUSH EASTWARD THROUGH THE DAY AND PRESSURE GRADIENT BEGINS TO RELAX DURING THE AFTERNOON HOURS. NAM/GFS BUFR SOUNDINGS SUGGEST SOME LIGHT SNOW SHOWERS OR FLURRIES OVER NORTHERN IOWA THROUGH 18Z BUT RAP SHOWING LOSS OF ICE INTRODUCTION IN THE COLUMN PERIODICALLY DURING THE MORNING. SEVERAL CURRENT OBSERVATIONS ACROSS NORTHERN IOWA REPORTING DZ/UP SUGGESTING THIS IS ALREADY OCCURRING. FORCING REMAINS WEAK BUT LOOKS TO BE ENOUGH TO WARRANT THE MENTION OF PATCHY FZDZ ACROSS THE NORTHEAST THROUGH 18Z. WENT CLOSE TO GUIDANCE TODAY FOR MAX TEMPERATURES AS MODELS ARE IN GOOD AGREEMENT AND FELT NO REASON TO DEVIATE MUCH FROM THEM. THIS RESULTED IN TWEAKING TEMPS UP SLIGHTLY ACROSS THE SOUTH. NOT EXPECTING STRATUS TO CLEAR OUT ACROSS THE SOUTHWEST UNTIL AFTER 21Z WHEN THE PRESSURE GRADIENT BEGINS TO WEAKEN. KEPT OVERCAST OVER THE NORTH TO EAST THROUGH 00Z TUESDAY AS LOW LEVEL MOISTURE REMAINS PERSISTENT WITHIN THE CAA. .LONG TERM /TONIGHT THROUGH SUNDAY/... THE UPPER LOW PRESSURE WILL CONTINUE TO RACE OFF TO THE EAST TONIGHT AND BE NEAR MAIN BY 12Z TUESDAY MORNING. THIS WILL ALLOW MUCH DRIER AIR TO FILTER INTO THE STATE AS BROAD AREA OF HIGH PRESSURE SHIFTS EAST INTO THE MIDWEST. GENERAL TRENDS FOR TUESDAY AND WEDNESDAY ARE WARMER. THE DRY AIR WILL WARM NICELY ON TUESDAY UNDER SOUTHWEST FLOW. THE FLOW WILL BECOME MORE DOWN SLOPE ORIENTED TUESDAY NIGHT INTO WEDNESDAY AHEAD A VIGOROUS UPPER WAVE THAT WILL ARRIVE ALONG WITH AN ASSOCIATED COLD FRONT WEDNESDAY NIGHT. TEMPERATURES ON WEDNESDAY WILL BE IN THE MID TO UPPER 40S OVER THE CENTRAL AND SOUTH AND A FEW LOCATIONS MAY HIT 50 IF ENOUGH SUN IS AVAILABLE. THE UPPER WAVE WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. GUSTY NORTHWEST WINDS WILL KEEP COLD ADVECTION IN PLACE THROUGH THE DAY THURSDAY AND MAY HAVE SLOWLY FALLING TEMPERATURES DURING THE AFTERNOON. THE AIR MASS WITH THE SYSTEM WILL BE FAIRLY DRY WITH PWATS GENERALLY ONE QUARTER INCH OR LESS THEREFORE NO PRECIPITATION IS EXPECTED. ANOTHER UPPER WAVE WILL DROP INTO THE REGION THURSDAY NIGHT AND FRIDAY AND WILL HELP CARVE A LONG WAVE TROUGH OUT ACROSS THE NORTHERN PLAINS AND INTO THE EASTERN CONUS. THIS WILL BE ENHANCED AS HUDSON BAY UPPER LOW DROPS SOUTH INTO THE UPPER GREAT LAKES. 850 MB TEMPERATURES OVER THE STATE WILL BE AROUND -16C BY MID DAY FRIDAY. THE COLD AIR MASS WILL BE RELATIVELY DEEP AND WILL BE ABLE TO MIX WELL. THEREFORE DESPITE THE COLD AIR MASS...DEEP MIXING TO NEAR 850 MB WILL ALLOW TEMPERATURES RISE INTO THE UPPER TEENS TO UPPER 20S. SATURDAY AND SUNDAY WILL SEE GRADUAL MODERATION AS A WEAK RIDGE MOVES INTO THE STATE IN RESPONSE TO A STRONG SHORT WAVE DIVING INTO THE INTER MOUNTAIN WEST. && .AVIATION...11/12Z TIGHT PRESSURE GRADIENT WILL CONTINUE TO PRODUCE VERY WINDY CONDITIONS THROUGH THE DAY BEFORE WINDS DIMINISH PAST 00Z TUESDAY AS THE LOW MOVES EAST AND ALLOW THE GRADIENT TO WEAKEN. OCCASIONAL -SN WILL PERSIST THROUGH MIDDAY AFFECTING MAINLY MCW/ALO WITH IFR VIS AT TIMES. MVFR STRATUS IS LIKELY TO PERSIST THROUGH MUCH OF THE DAY AS WELL. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL NOON CST TODAY FOR IAZ004>007-015>017- 023>028-033>039-044>050-057>062-074-075-086. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1040 AM EST MON FEB 11 2013 .Forecast Update... Issued at 1040 AM EST Mon Feb 11 2013 Ran a quick update this morning mainly to increase cloud cover across the southeast. A rather thick upper level deck looks as if it will stream across the Cumberland area through much of the day as another wave rides up along the departing frontal boundary. Also tweaked temperature and dewpoint grids to account for current trends. The jury is still out on the decision for an advisory late this morning into this afternoon. Louisville (SDF) gusted to 36 mph earlier this morning and Frankfort just recently gusted to 37 mph. However, both the 12Z NAM and the latest RAP soundings continue to advertise only about 35 knots at the top of the mixed layer late this morning, staying nearly steady or slowly weakening through the afternoon despite a deepening mixed layer. Will continue to monitor observations over the next few hours, but current thinking is that this event will best be handled with an SPS (although an isolated 40 mph gust is certainly possible). && .Short Term (Today - Tuesday)... Issued at 315 AM EST Mon Feb 11 2013 Light showers/drizzle redeveloped late last night and early this morning. This is currently in the process of exiting the forecast area, with dry air and reduced cloud cover working into the region. A vertically stacked low pressure system will meander eastward across the Great Lakes today. This will set up a tight pressure gradient at the surface, with even stronger winds aloft. Partly to mostly sunny skies and cold air advection aloft will aid mixing those winds to the surface. Sustained speeds between 15 and 25 mph are expected, with some gusts near 40 mph possible. Southern Indiana and north-central Kentucky will experience the strongest winds, with slightly weaker winds across south-central Kentucky. The peak period for the strongest winds will be from about mid morning through the afternoon. Wind speeds will decrease this evening, as the pressure gradient relaxes with surface high pressure and ridging aloft taking control. The high temperature forecast for today is tricky, with the ongoing cold air advection. We remained quite mild overnight, but cooler air is approaching from the west. Believe highs in the mid to upper 40s will be possible across southern Indiana, with lower 50s across north-central Kentucky and mid 50s across south-central and east-central Kentucky. Some of these highs, particularly in the north, may occur this morning and hold steady or only increase a degree or two with solar heating this afternoon. Lows tonight will drop into the upper 20s and lower 30s, with mostly clear skies. Typical cooler locations could dip into the mid 20s. Expect dry conditions, light westerly winds and temperatures ranging from the mid 40s to low 50s Tuesday. Clouds will increase through the day, ahead of our next system. .Long Term (Tuesday Night - Sunday)... Issued at 300 AM EST Mon Feb 11 2013 ...Light Wintry Precip Possible Wednesday Morning... The main concern in the long term period will be the possibility of light wintry precip Wed morning as an upper trough moves through the Ohio Valley. Still quite a bit of model spread on the track of the QPF field as it passes through our region, but have sided with a track similar to the 0Z GFS, GFS ensembles, and GEM. The 0Z ECMWF looks too suppressed compared to previous model runs and the 0Z NAM is much farther north than previous model runs. Certainly going with a consistency forecast here on the track of precipitation. One common theme among 0Z model guidance regardless of track is the slower timing of this weather system through the region. This theme combined with very dry low layers at onset of precip were evidence enough to delay precip arrival by around 4-6 hrs from the previous forecast. Looks like we should see some virga entering the region by around midnight Tues night, but precip shouldn`t start reaching the ground until closer to sunrise with the best coverage during the late morning/early afternoon hours Wed. Precipitation will be quick hitting and on its way out by late afternoon or early evening Wed. As far as precip type, boundary layer temps will be our determining factor as it looks like we`ll see ice crystal growth aloft with the main slug of moisture. With mild antecedent air and ground temps, think that most of the precip should fall as a cold rain. However, thermal profiles indicate that southern Indiana and north central KY may be cold enough Wed morning in a 2-5 hr window around sunrise for some snowflakes to fall. Also models do indicate some weak deformation with this system so if some heavier bands of precip set up in an environment with boundary layer temps close to freezing, we could see a change over to all snow briefly in heavier bands. Still with ground temps running in the lower 40s and low temps expected in the lower 30 to mid 30s across the area, think that any light snow accums would be short lived and shouldn`t cause much of a travel issue. Still stay abreast of the forecast for Wed morning`s commute as any changes in the thermal profile will affect ptype and potentially travel impacts. High temps on Wed are expected to top out in the lower 40s. Expect dry conditions for Thurs as zonal flow will dominate our region while a potent trough digs across the Plains states. This trough will push into the Midwest for the weekend creating a cool down. We`ll go from highs in the 40s to around 50 Thurs/Fri. to highs in the 30s Sat/Sun. Although no big weather makers look to impact the Ohio Valley with this upper trough, we will keep 20% POPs in the forecast as hard to time shortwaves that may produce light precip look possible Fri/Sat. && .Aviation (12Z TAF Issuance)... Issued at 620 AM EST Mon Feb 11 2013 Expect VFR conditions at all TAF sites this forecast period. Could see a few Cu at the top of a relatively deep mixing layer later this afternoon, along with a some high clouds from a southern stream system. However, the big issue today will be gusty west winds. Winds will continue a transition to west-southwest and be quite gusty, as the pressure gradient strengthens with a vertically stacked low meandering east across the Great Lakes. Wind speeds will peak just over 20 knots at BWG and just over 30 knots at SDF and LEX. Gusts should settle down around sunset, with speeds decreasing overnight as high pressure takes control. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........KD Short Term.......MJP Long Term........AMS Aviation.........MJP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
653 AM EST MON FEB 11 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 525 AM EST MON FEB 11 2013 PER WATER VAPOR IMAGERY AND RUC ANALYSIS...MID LEVEL LOW IS CURRENTLY SPINNING EASTWARD OVER NRN WI ATTM. ASSOCIATED SFC LOW APPEARS TO BE NEARING THE AREA BTWN WATERSMEET AND IRON RIVER. WHILE MAIN BAND OF WAA/ISENTROPIC ASCENT PCPN HAS PUSHED WELL N AND E OF THE AREA...REGIONAL RADAR IMAGERY SHOWS AREAS OF MOSTLY LIGHT PCPN CIRCULATING AROUND THE MID LEVEL LOW. AHEAD OF THE LOW...LOW-LEVELS HAVE WARMED SUFFICIENTLY OVER ROUGHLY THE E HALF OF UPPER MI TO RESULT IN PTYPE BEING JUST RAIN EARLY THIS MORNING (SFC TEMPS HAVE EVEN RISEN TO THE MID/UPPER 30S). PCPN TRANSITIONS BACK TO SNOW OVER WRN UPPER MI AND NW WI. OVER THE NEXT SEVERAL HRS...COLUMN WILL COOL AS MID LEVEL LOW TRACKS EASTWARD. AS A RESULT...WHERE PCPN IS NOW RAIN...IT WILL CHANGE BACK TO ALL SNOW DURING THE MORNING. ATTENTION THEN TURNS TO POTENTIAL LAKE ENHANCEMENT TODAY. IT WON`T BE THE TYPICAL LAKE ENHANCED EVENT PRODUCING MDT/HVY SNOW THAT WOULD NORMALLY BE EXPECTED AT THIS TIME OF YEAR BECAUSE THE AIR MASS IS MILD ACROSS THE AREA RIGHT NOW (850MB TEMPS ARE -1 TO -5C OVER LAKE SUPERIOR). SO INITIALLY...EVEN AS WINDS INCREASE OUT OF THE N TO NW BEHIND SFC LOW...AIR MASS WILL BE TOO WARM FOR LAKE ENHANCEMENT THOUGH THERE WILL BE SOME TERRAIN ENHANCEMENT FROM THE UPSLOPING FLOW. OVER THE W...THERE WILL BE A WINDOW FOR LAKE ENHANCEMENT FROM LATE MORNING INTO THE AFTN AS 850MB TEMPS FALL BLO -7C. INTO NCNTRL UPPER MI...WINDOW LOOKS SHORTER LATE THIS AFTN/EVENING. THUS...PROBABLY SHOULDN`T SEE MUCH MORE THAN 2-4 INCHES OF SNOW OVER THE W TODAY. BEHIND THE SFC LOW...WINDS MORE QUICKLY BACK NW ACROSS NCNTRL UPPER MI WHICH WILL LIMIT LAKE ENHANCEMENT AND MORE QUICKLY DIMINISH TERRAIN ENHANCEMENT INTO MARQUETTE COUNTY. CONSIDERED DROPPING ADVY FOR MARQUETTE COUNTY... BUT WILL WAIT TO SEE HOW THINGS EVOLVE DURING THE MORNING OVER THE W TO GET AN IDEA OF HOW ENHANCEMENT WILL PLAY OUT OVER THE NCNTRL. IT`S POSSIBLE AN ADVY MAY BE NEEDED TO THE E OF MARQUETTE LATER THIS AFTN/EVENING...BUT EXPECTATION IS THAT SNOW ACCUMULATIONS WILL BE UNDER ADVY AMOUNTS. PERIOD OF GUSTY N/NW WINDS TO 30-35MPH ALONG LAKE SUPERIOR NW AND NCNTRL WILL LEAD TO SOME BLSN THIS AFTN/EVENING. AS FOR HEADLINES...CANCELLED ADVY FOR MENOMINEE/DELTA/ALGER EASTWARD AS TEMPS HAVE RISEN TO THE MID/UPPER 30S WITH ONLY RAIN FALLING. REMAINING ADVYS WERE NOT CHANGED. AS DEEPER MOISTURE EXITS TONIGHT...SNOW NEAR LAKE SUPERIOR SHOULD STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE MARGINAL AROUND THE THRESHOLD FOR LES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 424 AM EST MON FEB 11 2013 LINGERING LIGHT LAKE EFFECT IS EXPECTED FOR THE START OF THE LONG TERM PERIOD. BUT INCREASED DRYING FROM WEST TO EAST...WARMING 850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE SURFACE RIDGE MOVING ACROSS THE REGION ON TUESDAY WILL LEAD QUICKLY DIMINISHING LAKE EFFECT SNOW DURING THE DAY TUESDAY. CLOUDS WILL ALSO BE ON THE DECREASE THROUGH THE DAY AND GOING FORECAST HAS A DECENT TREND ON THAT IDEA. THE HIGH PRESSURE RIDGE QUICKLY SLIDES EAST ON TUESDAY AFTERNOON/EVENING AND AREA COMES UNDER THE INFLUENCE OF SEVERAL NORTHERN STREAM WAVES FOR THE REST OF THE WORK WEEK. THE FIRST WAVE...NEAR LAKE WINNIPEG AT 00Z WED...WILL DIVE SOUTHEAST ACROSS LAKE SUPERIOR ON WEDNESDAY. BEST DEEP MOISTURE LOOKS TO STAY OVER THE NORTHEAST HALF OF THE LAKE AND WITH GENERALLY WESTERLY FLOW ACROSS THE CWA...DON/T EXPECT MUCH FOR PRECIPITATION CHANCES ON WEDNESDAY EVEN THOUGH THE BROAD SURFACE TROUGH MOVES THROUGH. THE NEXT SHORTWAVE...TRACKING FARTHER TO THE SOUTHEAST...WILL DEPART ALBERTA ON WEDNESDAY AND MOVE INTO THE NORTHERN PLAINS ON WEDNESDAY EVENING AND THEN TRACK INTO THE WESTERN GREAT LAKES FOR THURSDAY. STILL SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND ENSEMBLE MEMBERS FROM THE GFS/GEM/ECMWF WITH THE STRENGTH OF THIS SHORTWAVE AND THE RESULTING STRENGTH/LOCATION OF THE ASSOCIATED SURFACE LOW. HPC PREFERS A BLEND OF THE 18Z GFES AND 12Z ECMWF ENS MEAN AND THAT SEEMS LIKE A DECENT COMPROMISE. THIS WOULD SWEEP THE SHORTWAVE THROUGH WISCONSIN ON THURSDAY AND HAVE A LOW 1000S MB LOW MOVING THROUGH NORTHERN WISCONSIN OR SOUTHERN UPPER MICHIGAN. AT THIS POINT...WOULD JUST EXPECT A DUSTING TO A COUPLE INCHES OF SNOW WITH THIS SYSTEM...UNLESS THE STRONGER GFS SOLUTION IS CORRECT WHICH WOULD PRODUCE ADVISORY SNOWFALL. ANOTHER SHORTWAVE DIVING SSE ON THE BACK SIDE OF THE THURSDAY SHORTWAVE WILL AMPLIFY THE UPPER TROUGH FURTHER AND LEAD TO IT MERGING WITH THE SOUTHERN STREAM FOR FRIDAY AND THE WEEKEND...WHILE AN UPPER RIDGE BUILDS OVER THE WRN CONUS. THIS WILL ALLOW COLDER AIR TO SPILL SOUTH ACROSS THE UPPER GREAT LAKES REGION AND PRODUCE A PERIOD OF BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. WITH THIS COLDER AIR...ALSO EXPECT THE AREA TO SEE LAKE EFFECT SNOW DUE TO 850MB TEMPS FALLING TOWARDS -21C BY SATURDAY. WITH A HIGH PRESSURE RIDGE EXPECTED TO BUILD INTO THE NORTHERN PLAINS DURING THIS TIME...WIND DIRECTIONS WILL DEPEND ON IF A LOW DEVELOPS AND MOVES UP THE ATLANTIC SEABOARD /ECMWF-YES AND GFS-MAYBE/. IF IT DOES OCCUR...WOULD EXPECT MORE N-NNW WIND LAKE EFFECT...WHILE NW LAKE EFFECT WOULD BE EXPECTED WITHOUT THE LOW. SINCE MODELS ARE MORE CONSISTENT ON LAKE EFFECT POTENTIAL FOR FRIDAY AND THE WEEKEND...WILL CONTINUE TO TREND POPS UP. A LITTLE TOO EARLY TO PIN DOWN TIMING/LOCATION FOR LIKELY POPS...BUT THERE APPEARS TO BE SEVERAL WEAK WAVES MOVING THROUGH THAT WILL INCREASE MOISTURE AND INTENSIFY THE LAKE EFFECT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 652 AM EST MON FEB 11 2013 LIFR/IFR CONDITIONS WITH -SN WILL PREVAIL AT KIWD/KCMX/KSAW THROUGH THE MORNING HRS AS A LOW PRES SYSTEM MOVES ACROSS UPPER MI. IN THE WAKE OF THE LOW...EXPECT STRONGER N TO NW WINDS TO DEVELOP FROM W TO E THIS MORNING/EARLY AFTN. GUSTS SHOULD BE IN THE 20-30KT RANGE. MID TO LATE AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS EXPECTED AS THE STORM SYSTEM MOVES OFF TO THE EAST. MVFR CIGS MAY SCATTER OUT LATE TONIGHT AT KIWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT KSAW UNDER DOWNSLOPING W TO NW WINDS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 525 AM EST MON FEB 11 2013 ON THE BACKSIDE OF LOW PRES MOVING ACROSS UPPER MI/ERN LAKE SUPERIOR TODAY...EXPECT A PERIOD OF N TO NW GALES TO DEVELOP FROM NW TO SE DURING THE DAY. APPROACHING HIGH PRES RIDGE WILL THEN CAUSE WINDS TO DIMINISH TO UNDER 25 KTS TONIGHT. WINDS WILL BECOME W-SW TUE/TUE NIGHT AS THE RIDGE SHIFTS TO THE E. THE W-SW FLOW WILL BE STRONGEST BTWN THE KEWEENAW AND ISLE ROYALE (POSSIBLY 20-30KT). LIGHTER WINDS UNDER 20KT SHOULD THEN PREVAIL LATER TUE NIGHT THRU WED NIGHT UNDER WEAKER PRES GRADIENT. LOW PRES WILL MOVE ACROSS THE WRN LAKES THU. BEHIND THE LOW...NORTHERLY WINDS WILL INCREASE INTO THE 15-30KT RANGE...STRONGEST OVER CNTRL/ERN LAKE SUPERIOR. FREEZING SPRAY WILL ALSO RETURN AS ARCTIC AIR FLOWS BACK INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY FOR MIZ001>003-009. WINTER WEATHER ADVISORY UNTIL 10 AM CST THIS MORNING FOR MIZ010- 011. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004- 005-084. LAKE SUPERIOR... GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS EVENING FOR LSZ248>250-265-266. GALE WARNING UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR LSZ162. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264. GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
526 AM EST MON FEB 11 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 525 AM EST MON FEB 11 2013 PER WATER VAPOR IMAGERY AND RUC ANALYSIS...MID LEVEL LOW IS CURRENTLY SPINNING EASTWARD OVER NRN WI ATTM. ASSOCIATED SFC LOW APPEARS TO BE NEARING THE AREA BTWN WATERSMEET AND IRON RIVER. WHILE MAIN BAND OF WAA/ISENTROPIC ASCENT PCPN HAS PUSHED WELL N AND E OF THE AREA...REGIONAL RADAR IMAGERY SHOWS AREAS OF MOSTLY LIGHT PCPN CIRCULATING AROUND THE MID LEVEL LOW. AHEAD OF THE LOW...LOW-LEVELS HAVE WARMED SUFFICIENTLY OVER ROUGHLY THE E HALF OF UPPER MI TO RESULT IN PTYPE BEING JUST RAIN EARLY THIS MORNING (SFC TEMPS HAVE EVEN RISEN TO THE MID/UPPER 30S). PCPN TRANSITIONS BACK TO SNOW OVER WRN UPPER MI AND NW WI. OVER THE NEXT SEVERAL HRS...COLUMN WILL COOL AS MID LEVEL LOW TRACKS EASTWARD. AS A RESULT...WHERE PCPN IS NOW RAIN...IT WILL CHANGE BACK TO ALL SNOW DURING THE MORNING. ATTENTION THEN TURNS TO POTENTIAL LAKE ENHANCEMENT TODAY. IT WON`T BE THE TYPICAL LAKE ENHANCED EVENT PRODUCING MDT/HVY SNOW THAT WOULD NORMALLY BE EXPECTED AT THIS TIME OF YEAR BECAUSE THE AIR MASS IS MILD ACROSS THE AREA RIGHT NOW (850MB TEMPS ARE -1 TO -5C OVER LAKE SUPERIOR). SO INITIALLY...EVEN AS WINDS INCREASE OUT OF THE N TO NW BEHIND SFC LOW...AIR MASS WILL BE TOO WARM FOR LAKE ENHANCEMENT THOUGH THERE WILL BE SOME TERRAIN ENHANCEMENT FROM THE UPSLOPING FLOW. OVER THE W...THERE WILL BE A WINDOW FOR LAKE ENHANCEMENT FROM LATE MORNING INTO THE AFTN AS 850MB TEMPS FALL BLO -7C. INTO NCNTRL UPPER MI...WINDOW LOOKS SHORTER LATE THIS AFTN/EVENING. THUS...PROBABLY SHOULDN`T SEE MUCH MORE THAN 2-4 INCHES OF SNOW OVER THE W TODAY. BEHIND THE SFC LOW...WINDS MORE QUICKLY BACK NW ACROSS NCNTRL UPPER MI WHICH WILL LIMIT LAKE ENHANCEMENT AND MORE QUICKLY DIMINISH TERRAIN ENHANCEMENT INTO MARQUETTE COUNTY. CONSIDERED DROPPING ADVY FOR MARQUETTE COUNTY... BUT WILL WAIT TO SEE HOW THINGS EVOLVE DURING THE MORNING OVER THE W TO GET AN IDEA OF HOW ENHANCEMENT WILL PLAY OUT OVER THE NCNTRL. IT`S POSSIBLE AN ADVY MAY BE NEEDED TO THE E OF MARQUETTE LATER THIS AFTN/EVENING...BUT EXPECTATION IS THAT SNOW ACCUMULATIONS WILL BE UNDER ADVY AMOUNTS. PERIOD OF GUSTY N/NW WINDS TO 30-35MPH ALONG LAKE SUPERIOR NW AND NCNTRL WILL LEAD TO SOME BLSN THIS AFTN/EVENING. AS FOR HEADLINES...CANCELLED ADVY FOR MENOMINEE/DELTA/ALGER EASTWARD AS TEMPS HAVE RISEN TO THE MID/UPPER 30S WITH ONLY RAIN FALLING. REMAINING ADVYS WERE NOT CHANGED. AS DEEPER MOISTURE EXITS TONIGHT...SNOW NEAR LAKE SUPERIOR SHOULD STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE MARGINAL AROUND THE THRESHOLD FOR LES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 424 AM EST MON FEB 11 2013 LINGERING LIGHT LAKE EFFECT IS EXPECTED FOR THE START OF THE LONG TERM PERIOD. BUT INCREASED DRYING FROM WEST TO EAST...WARMING 850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE SURFACE RIDGE MOVING ACROSS THE REGION ON TUESDAY WILL LEAD QUICKLY DIMINISHING LAKE EFFECT SNOW DURING THE DAY TUESDAY. CLOUDS WILL ALSO BE ON THE DECREASE THROUGH THE DAY AND GOING FORECAST HAS A DECENT TREND ON THAT IDEA. THE HIGH PRESSURE RIDGE QUICKLY SLIDES EAST ON TUESDAY AFTERNOON/EVENING AND AREA COMES UNDER THE INFLUENCE OF SEVERAL NORTHERN STREAM WAVES FOR THE REST OF THE WORK WEEK. THE FIRST WAVE...NEAR LAKE WINNIPEG AT 00Z WED...WILL DIVE SOUTHEAST ACROSS LAKE SUPERIOR ON WEDNESDAY. BEST DEEP MOISTURE LOOKS TO STAY OVER THE NORTHEAST HALF OF THE LAKE AND WITH GENERALLY WESTERLY FLOW ACROSS THE CWA...DON/T EXPECT MUCH FOR PRECIPITATION CHANCES ON WEDNESDAY EVEN THOUGH THE BROAD SURFACE TROUGH MOVES THROUGH. THE NEXT SHORTWAVE...TRACKING FARTHER TO THE SOUTHEAST...WILL DEPART ALBERTA ON WEDNESDAY AND MOVE INTO THE NORTHERN PLAINS ON WEDNESDAY EVENING AND THEN TRACK INTO THE WESTERN GREAT LAKES FOR THURSDAY. STILL SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND ENSEMBLE MEMBERS FROM THE GFS/GEM/ECMWF WITH THE STRENGTH OF THIS SHORTWAVE AND THE RESULTING STRENGTH/LOCATION OF THE ASSOCIATED SURFACE LOW. HPC PREFERS A BLEND OF THE 18Z GFES AND 12Z ECMWF ENS MEAN AND THAT SEEMS LIKE A DECENT COMPROMISE. THIS WOULD SWEEP THE SHORTWAVE THROUGH WISCONSIN ON THURSDAY AND HAVE A LOW 1000S MB LOW MOVING THROUGH NORTHERN WISCONSIN OR SOUTHERN UPPER MICHIGAN. AT THIS POINT...WOULD JUST EXPECT A DUSTING TO A COUPLE INCHES OF SNOW WITH THIS SYSTEM...UNLESS THE STRONGER GFS SOLUTION IS CORRECT WHICH WOULD PRODUCE ADVISORY SNOWFALL. ANOTHER SHORTWAVE DIVING SSE ON THE BACK SIDE OF THE THURSDAY SHORTWAVE WILL AMPLIFY THE UPPER TROUGH FURTHER AND LEAD TO IT MERGING WITH THE SOUTHERN STREAM FOR FRIDAY AND THE WEEKEND...WHILE AN UPPER RIDGE BUILDS OVER THE WRN CONUS. THIS WILL ALLOW COLDER AIR TO SPILL SOUTH ACROSS THE UPPER GREAT LAKES REGION AND PRODUCE A PERIOD OF BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. WITH THIS COLDER AIR...ALSO EXPECT THE AREA TO SEE LAKE EFFECT SNOW DUE TO 850MB TEMPS FALLING TOWARDS -21C BY SATURDAY. WITH A HIGH PRESSURE RIDGE EXPECTED TO BUILD INTO THE NORTHERN PLAINS DURING THIS TIME...WIND DIRECTIONS WILL DEPEND ON IF A LOW DEVELOPS AND MOVES UP THE ATLANTIC SEABOARD /ECMWF-YES AND GFS-MAYBE/. IF IT DOES OCCUR...WOULD EXPECT MORE N-NNW WIND LAKE EFFECT...WHILE NW LAKE EFFECT WOULD BE EXPECTED WITHOUT THE LOW. SINCE MODELS ARE MORE CONSISTENT ON LAKE EFFECT POTENTIAL FOR FRIDAY AND THE WEEKEND...WILL CONTINUE TO TREND POPS UP. A LITTLE TOO EARLY TO PIN DOWN TIMING/LOCATION FOR LIKELY POPS...BUT THERE APPEARS TO BE SEVERAL WEAK WAVES MOVING THROUGH THAT WILL INCREASE MOISTURE AND INTENSIFY THE LAKE EFFECT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1208 AM EST MON FEB 11 2013 EXPECT PREDOMINANT IFR WITH OCNL LIFR CONDITIONS OVERNIGHT WITH PERIODS OF LIGHT SNOW. VLIFR FOG AT CMX IS EXPECTED TO IMPROVE AS WINDS BACK TO THE NORTHEAST. WITH WINDS BECOMING NORTH TODAY...A PERIOD OF LAKE ENHANCED SNOW WILL HELP KEEP VSBY IN THE IFR RANGE. BY MID TO LATE AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS EXPECTED AS THE STORM SYSTEM MOVES OFF TO THE NORTHEAST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 525 AM EST MON FEB 11 2013 ON THE BACKSIDE OF LOW PRES MOVING ACROSS UPPER MI/ERN LAKE SUPERIOR TODAY...EXPECT A PERIOD OF N TO NW GALES TO DEVELOP FROM NW TO SE DURING THE DAY. APPROACHING HIGH PRES RIDGE WILL THEN CAUSE WINDS TO DIMINISH TO UNDER 25 KTS TONIGHT. WINDS WILL BECOME W-SW TUE/TUE NIGHT AS THE RIDGE SHIFTS TO THE E. THE W-SW FLOW WILL BE STRONGEST BTWN THE KEWEENAW AND ISLE ROYALE (POSSIBLY 20-30KT). LIGHTER WINDS UNDER 20KT SHOULD THEN PREVAIL LATER TUE NIGHT THRU WED NIGHT UNDER WEAKER PRES GRADIENT. LOW PRES WILL MOVE ACROSS THE WRN LAKES THU. BEHIND THE LOW...NORTHERLY WINDS WILL INCREASE INTO THE 15-30KT RANGE...STRONGEST OVER CNTRL/ERN LAKE SUPERIOR. FREEZING SPRAY WILL ALSO RETURN AS ARCTIC AIR FLOWS BACK INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY FOR MIZ001>003-009. WINTER WEATHER ADVISORY UNTIL 10 AM CST THIS MORNING FOR MIZ010- 011. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004- 005-084. LAKE SUPERIOR... GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS EVENING FOR LSZ248>250-265-266. GALE WARNING UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR LSZ162. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264. GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...JLB MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS HASTINGS NE
524 AM CST MON FEB 11 2013 .AVIATION...12Z TAF. MAIN CONCERN FOR THE FIRST PART OF THE TAF PERIOD IS GUSTY NORTHWEST WINDS AS SFC PRESSURE GRADIENT WILL REMAIN TIGHT THRU THE MORNING. WIND GUSTS NEAR 25KTS ARE POSSIBLE UNTIL GRADIENT RELAXES THIS AFTN/EVENING AS SFC HIGH PRESSURE SETTLES ONTO THE CENTRAL PLAINS. KGRI WILL BE ON THE SOUTHWEST EDGE OF MVFR CLOUDS THIS MORNING...BUT BRUNT OF LOW CLOUDS ARE EXPECTED TO REMAIN EAST AS THE UPPER LOW PRESSURE SYSTEM CONTINUES TO LIFT OUT AND DID NOT BRING ANY CIGS INTO THE TERMINAL...THEN SCATTERED MID/HIGH CLOUDS ARE EXPECTED TONIGHT. && .PREV DISCUSSION... /ISSUED 433 AM CST MON FEB 11 2013/ SHORT TERM...THROUGH WEDNESDAY NIGHT. COMPARED TO THE PAST FEW DAYS...THESE NEXT 72 HOURS ARE LOOKING FAIRLY BENIGN WITH ESSENTIALLY ZERO RISK OF PRECIPITATION. HOWEVER...BOTH TUESDAY AND ESPECIALLY WEDNESDAY ARE TRENDING A BIT BREEZIER THAN PREVIOUSLY ADVERTISED...BUT ALSO A BIT WARMER AS WELL. 09Z OBJECTIVE SURFACE ANALYSIS PLACED THE CENTER OF THE DEPARTING...STRONG 991MB LOW OVER CENTRAL WI...WITH THE CENTRAL PLAINS CAUGHT WITHIN THE BACKSIDE OF THE TIGHT PRESSURE GRADIENT BETWEEN THIS LOW AND A ROUGHLY 1024MB HIGH OVER WY. A FAIRLY PRONOUNCED GRADIENT IN WIND SPEEDS IS EVIDENT ACROSS THE CWA AT THIS TIME...WITH NORTHWESTERLY SPEEDS AVERAGING NO MORE THAN 10-15 MPH IN SOUTHWEST AREAS...WHILE MOST CENTRAL/NORTHEAST AREAS CONTINUE TO REPORT SUSTAINED SPEEDS AT LEAST 15-20 MPH WITH GUSTS UP TO NEAR 30 MPH. FORTUNATELY THOUGH...SPEEDS HAVE FINALLY EASED WELL BELOW ADVISORY CRITERIA...WHICH TOOK A FEW HOURS LONGER EARLIER TONIGHT THAN ORIGINALLY THOUGHT. ANY LINGERING FLURRIES FROM EARLIER TONIGHT HAVE ALSO DEPARTED TO THE NORTHEAST...WITH IN FACT NEARLY FULLY CLEAR SKIES NOW OVER ALL BUT THE FAR EASTERN EDGES OF THE CWA WHERE SOME LOW STRATUS LINGERS. PRE-DAWN TEMPERATURES ARE FAIRLY UNIFORM ACROSS THE CWA...WITH MOST AREAS LIKELY HEADING FOR LOWS SOMEWHERE BETWEEN 21-27. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRMED AN ACTIVE PATTERN ACROSS THE CONUS...WITH THE NEARLY VERTICALLY STACKED CLOSED LOW DEPARTING OVER THE WI AREA...WHILE OFF TO OUR SOUTHWEST...A CURRENTLY OPEN 500MB SHORTWAVE TROUGH WAS CENTERED NEAR THE CA/NV/UT/AZ BORDERS...WITH ONLY THE SLIGHTEST HINT OF SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS IN BETWEEN THESE TWO PRIMARY LOWS. FORECAST-WISE TODAY...WHILE BY NO MEANS AS WINDY AS YESTERDAY...A HEALTHY NORTHWEST BREEZE OF 15-20 MPH WITH GUSTS 25+ MPH WILL PERSIST WELL INTO THE EARLY-MID AFTERNOON HOURS ACROSS ROUGHLY THE NORTHEAST 1/2 OF THE CWA THANKS TO EFFICIENT MIXING TO AROUND 850MB...BEFORE EASING MORE NOTICEABLY BETWEEN 3 PM AND SUNSET. ANY LINGERING/PRESUMABLY MINOR BLOWING SNOW ISSUES IN THE ORD AREA SHOULD CONTINUE TO ABATE WITH TIME. WIND SPEEDS ACROSS ROUGHLY THE SOUTHWEST 1/2 OF THE AREA WILL AVERAGE AT LEAST 5 MPH LIGHTER...AND ALSO START TO EASE UP SOONER ESPECIALLY THIS AFTERNOON AS A BROAD 1025MB RIDGE AXIS SETTLES INTO THE AREA. CLOUD-WISE...WHILE NEARLY THE ENTIRE AREA WILL START OUT WITH PLENTY OF SUNSHINE...THE AFTERNOON HOURS WILL BRING AT LEAST PARTLY CLOUDY SKIES TO MAINLY THE SOUTHWEST 1/2 OF THE CWA AS MID- HIGH CLOUDS SPREAD OVERHEAD DOWNSTREAM FROM THE SOUTHWEST CONUS LOW. THERE ARE SUGGESTIONS FROM THE LATEST HRRR RUNS THAT SOME SCATTERED LOW CLOUDS COULD ALSO INCREASE MAINLY THIS AFTERNOON IN SOME AREAS NORTH OF I-80...BUT WILL KEEP IT A MOSTLY SUNNY THEME HERE AT LEAST FOR NOW. AS FOR TEMPS...FOLLOWED THE 00Z NAM/05Z RAP SOLUTION RATHER CLOSELY...WHICH RESULTED IN A 1-3 DEGREE UPWARD NUDGE FROM PREVIOUS FORECAST...NOW RANGING FROM LOW 30S FAR NORTH...MID 30S CENTRAL...LOW 40S SOUTH MAINLY KS ZONES. ITS WORTH NOTING THAT THE 06Z NAM CAME IN COLDER FOR NORTHWEST COUNTIES...BUT THIS APPEARS TO BE A RESULT OF AN OVERDONE MODEL- INITIALIZED SNOW FIELD. THAT BEING SAID...CONFIDENCE IN TEMPS ISN/T QUITE AS HIGH ESPECIALLY FOR THE ORD AREA...WHERE A LIGHT COATING OF SNOW FROM YESTERDAY ALONG WITH A WIND DIRECTION BLOWING OFF OF THE DEEPER SNOW COVER OVER THE SANDHILLS COULD WORK TO HOLD THINGS DOWN A BIT. THIS EVENING/TONIGHT...CONFIDENCE REMAINS HIGH THAT THE ENTIRE CWA REMAINS PRECIPITATION-FREE...BUT THINGS DEFINITELY START TO TURN MORE INTERESTING A FEW COUNTIES TO OUR SOUTH...AS THE AFOREMENTIONED SOUTHWESTERN CONUS MID LEVEL SHORTWAVE TROUGH STARTS CLOSING OFF A BIT AS IT HEADS EAST INTO NM. FORCING DOWNSTREAM FROM THIS WAVE WILL SPREAD DECENT CHANCES FOR AT LEAST LIGHT ACCUMULATING SNOW INTO MAINLY THE SOUTHWEST 1/4 OF KS ESPECIALLY AFTER MIDNIGHT. WHILE A CONSENSUS OF VARIOUS MODELS SUCH AS THE NAM/ECMWF/4KM WRF-NMM KEEPS ANY OF THIS SNOW AT LEAST 80 MILES SOUTH OF THE FAR SOUTHERN CWA...THE NEW 06Z GFS HAS SUDDENLY TRENDED SLIGHTLY FARTHER NORTH...BRINGING AT LEAST A DUSTING OF SNOW WITHIN ROUGHLY 20 MILES OF FAR SOUTHERN ROOKS/OSBORNE COUNTIES. FOR NOW WILL DISCOUNT THIS RUN AS A NORTHERN OUTLIER AND STAND FIRM THAT THIS SYSTEM WILL NOT BE AN ISSUE FOR OUR CWA...AND BRING ONLY A PERIOD OF PARTLY/MOSTLY CLOUDY SKIES TO MAINLY OUR SOUTHERN COUNTIES. AT THE SURFACE TONIGHT...INITIALLY FAIRLY LIGHT/VARIABLE WINDS NEAR THE RIDGE AXIS WILL TAKE ON A SLIGHTLY STEADIER SOUTHWESTERLY COMPONENT LATE IN THE NIGHT IN RESPONSE TO A SUBTLE PASSING TROUGH AXIS. GIVEN THESE LIGHT WESTERLY BREEZES AND ALSO A FAIR AMOUNT OF PASSING CLOUD ESPECIALLY SOUTH...GENERALLY RAISED LOW TEMPS 2-4 DEGREES FROM PREVIOUS GRIDS...WITH ALL BUT FAR NORTHWESTERN AREAS HOLDING UP GENERALLY 17-22. TUESDAY DAYTIME...IN A CONTINUATION FROM LATE WED NIGHT ACCUMULATING SNOW WILL CONTINUE TO OUR SOUTH...TRACKING EASTWARD MAINLY ALONG/SOUTH OF THE KS/OK BORDER...AS THE PRIMARY 500MB SHORTWAVE ENDS UP OVER SOUTHERN/WESTERN OK BY DAYS END. AGAIN THOUGH...NO LOCAL IMPACT ANTICIPATED OTHER THAN MORE MID-HIGH CLOUD OVER KS ZONES VERSUS NEB ZONES. AT THE SURFACE...HIGH PRESSURE CENTERED TO THE WEST WILL DRIVE A WESTERLY DOWNSLOPE WIND COMPONENT ACROSS THE ENTIRE CWA...AND HAVE INCREASED SUSTAINED SPEEDS CLOSER TO 15 MPH WITH HIGHER GUSTS MAINLY FOR THE NORTHERN 1/2 OF THE CWA. ASSUMING THAT SUNSHINE IS FAIRLY PLENTIFUL IN MOST AREAS...AND GIVEN SLIGHT LOW LEVEL WARMING VERSUS MONDAY...SEE LITTLE REASON WHY THIS DOWNSLOPE WIND WON/T BRING A DECENT BOOST IN HIGH TEMPS...AND HAVE RAISED HIGHS GENERALLY 2-4 DEGREES FROM PREVIOUS FORECAST...ESPECIALLY IN EASTERN AREAS FARTHEST REMOVED FROM THE WESTERN/NORTH CENTRAL NEB SNOW FIELD. THIS NOW YIELDS HIGHS IN THE MID-UPPER 40S MOST AREAS...EXCEPT LOW 40S FAR NORTHWEST. TUESDAY NIGHT...THE SOUTHERN CONUS SHORTWAVE TROUGH TREKS EAST INTO THE AR/TN AREA...HELPING TRANSITION THE FLOW OVER THE CENTRAL PLAINS TO MORE PRONOUNCED NORTHWESTERLY...BUT WITH NO IMPACTFUL DISTURBANCES. ALTHOUGH A DECENT BATCH OF MID LEVEL CLOUDS COULD SAG SOUTHWARD ACROSS THE CWA...NOT EVEN EXPECTING FLURRIES AT THIS TIME. AT THE SURFACE...A LIGHT BUT STEADY 5-10 MPH WESTERN COMPONENT SHOULD AGAIN HELP KEEP TEMPS FROM FALLING TOO FAR...AND NUDGED UP PREVIOUS LOWS VERY SLIGHTLY...KEEPING MOST PLACES UP BETWEEN 21-24 DEGREES. WEDNESDAY...DRY NORTHWESTERLY FLOW ALOFT PERSISTS...AS THE LOCAL AREA REMAINS DOWNSTREAM FROM A LOW AMPLITUDE/CLIPPER-TYPE SHORTWAVE TROUGH SLIPPING OUT OF CANADA TO THE DAKOTAS/MN BORDER AREA BY DAYS END. UNDER GENERALLY PARTLY CLOUDY SKIES...A CONTINUED DOWNSLOPE WESTERLY WIND AND WARMER AIR EVIDENT ABOVE THE SURFACE AT 850MB SHOULD CONTINUE THE WARMING TREND FROM TUESDAY...AND HAVE MADE A VERY SLIGHT UPWARD NUDGE TO PREVIOUS HIGHS WITH MOST OF THE CWA INTO THE 50-53 RANGE...EXCEPT COOLER MID-UPPER 40S MAINLY IN OUR FAR NORTH/NORTHWEST FRINGES WHERE THE SNOW FIELD COULD STILL POSSIBLY EXERT SOME INFLUENCE. THE OVERALL BIGGEST CHANCE TO WEDNESDAY INVOLVED WIND SPEEDS...WHICH WERE UPPED AT LEAST 6-8 MPH FROM PREVIOUS GRIDS INTO BREEZY TERRITORY...AND NOW EXPECT SEVERAL HOURS OF SUSTAINED WEST-NORTHWEST SPEEDS 15-20 MPH WITH SOME HIGHER GUSTS. FORTUNATELY FOR POSSIBLE FIRE WEATHER CONCERNS...RELATIVE HUMIDITY VALUES ARE FORECAST TO FALL NO LOWER THAN THE UPPER-20S PERCENT...AND THIS IS ONLY IN A SMALL PART OF KS ZONES. WEDNESDAY NIGHT...THE AFOREMENTIONED NORTHERN PLAINS CLIPPER-SYSTEM DIVES DOWN MAINLY INTO IA/WI...WHILE AT THE SURFACE THE LEADING EDGES OF A MODEST COLD FRONT WILL ENTER THE LOCAL AREA. ALTHOUGH THE ORIENTATION OF THE UPPER JET ON THE WESTERN SIDE OF THIS DISTURBANCE ALONG WITH SOME MID LEVEL RH PROGS FROM MODELS SUCH AS THE 06Z NAM SUGGEST THAT A FEW FLURRIES MIGHT NOT BE OUT OF THE QUESTION FOR PARTS OF THE CWA...WILL KEEP ALL PRECIP MENTION OUT FOR NOW WITH POSSIBLY SLIGHTLY BETTER FLURRY CHANCES HOLDING OFF UNTIL THE THURS DAYTIME HOURS. MADE VERY LITTLE CHANGE TO LOW TEMPS WITH MID-UPPER 20S ALL AREAS. LONG TERM...THURSDAY THROUGH SUNDAY...AT THE ONSET OF THE EXTENDED PERIODS...100KT TO 120KT JET H3 JET STREAKS WILL NOSE SOUTH FM ALBERTA ACROSS THE EASTERN SLOPES OF THE NORTHERN ROCKIES CARVING A TROUGH ACROSS THE EASTERN TWO THIRDS OF THE CONUS. IN A NORTHWEST FLOW REGIME ACROSS THE CENTRAL PLAINS...COLD AIR WILL BACK IN FM THE NORTHEAST WITH THE MAIN THERMAL TROUGH ORIENTED FM ONTARIO THRU THE GREAT LAKES REGION. ENERGY TRANSLATING SOUTHEAST THRU FLOW AND A PUSH OF COLD AIR SOUTH THURSDAY COULD GENERATE SNOW FLURRIES IN OUR NORTHERN ZONES. FRIDAY WILL SEE A REINFORCING SHOT OF COLD AIR AS A STRONGER JET STREAK DIVES SOUTH ALONG THE FRONT RANGE OF THE ROCKIES AND ADDITIONAL SHORTWAVE ENERGY TRANSLATES ON THE WESTERN EDGE OF THE TROUGH WHICH ULTIMATELY FURTHER DEEPENS TO THE TROUGH ACROSS CENTRAL AND EASTERN CONUS. CURRENTLY HAVE FLURRIES IN THE FORECAST ON FRIDAY AND THIS IS STILL WARRANTED WITH FROPA/UPPER DYNAMICS. TEMPS WILL TREND COLDER THURSDAY...CLOSER TO SEASONAL NORMALS...AND WILL DROP FURTHER FRIDAY WITH STRONGER COLD FRONT. A COLD SURFACE HIGH PRESSURE SYSTEM WILL SETTLE ACROSS THE CENTRAL PLAINS BEHIND THE FRONT FRIDAY NIGHT...WHICH WILL RESULT IN TEMPS IN THE TEENS FOR LOWS. AFTER A COLD COUPLE OF DAYS FOR THE END OF THE WORKWEEK...THE WEATHER OVER THE WEEKEND TRENDS WARMER. THE SFC RIDGE AXIS SLIDES SOUTHEAST ON SATURDAY...ALLOWING FOR RETURN FLOW...AND ALOFT...THE UPPER TROUGH DEPARTS EASTWARD AND HEIGHTS BEGIN TO RISE ACROSS THE CENTRAL PLAINS. BY SUNDAY THE RIDGE WHICH WAS OVER THE ROCKIES SATURDAY REACHES THE INTERIOR CONUS..AND WARMER AIR SPREADS EASTWARD. SUNDAY IS LOOKING LIKE THE WARMEST OF THE EXTENDED PERIODS WITH HIGHS IN THE 40S FOR THE MOST PART AND 50S MAY NOT BE OUT OF THE QUESTION. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM/AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
433 AM CST MON FEB 11 2013 .SHORT TERM...THROUGH WEDNESDAY NIGHT. COMPARED TO THE PAST FEW DAYS...THESE NEXT 72 HOURS ARE LOOKING FAIRLY BENIGN WITH ESSENTIALLY ZERO RISK OF PRECIPITATION. HOWEVER...BOTH TUESDAY AND ESPECIALLY WEDNESDAY ARE TRENDING A BIT BREEZIER THAN PREVIOUSLY ADVERTISED...BUT ALSO A BIT WARMER AS WELL. 09Z OBJECTIVE SURFACE ANALYSIS PLACED THE CENTER OF THE DEPARTING...STRONG 991MB LOW OVER CENTRAL WI...WITH THE CENTRAL PLAINS CAUGHT WITHIN THE BACKSIDE OF THE TIGHT PRESSURE GRADIENT BETWEEN THIS LOW AND A ROUGHLY 1024MB HIGH OVER WY. A FAIRLY PRONOUNCED GRADIENT IN WIND SPEEDS IS EVIDENT ACROSS THE CWA AT THIS TIME...WITH NORTHWESTERLY SPEEDS AVERAGING NO MORE THAN 10-15 MPH IN SOUTHWEST AREAS...WHILE MOST CENTRAL/NORTHEAST AREAS CONTINUE TO REPORT SUSTAINED SPEEDS AT LEAST 15-20 MPH WITH GUSTS UP TO NEAR 30 MPH. FORTUNATELY THOUGH...SPEEDS HAVE FINALLY EASED WELL BELOW ADVISORY CRITERIA...WHICH TOOK A FEW HOURS LONGER EARLIER TONIGHT THAN ORIGINALLY THOUGHT. ANY LINGERING FLURRIES FROM EARLIER TONIGHT HAVE ALSO DEPARTED TO THE NORTHEAST...WITH IN FACT NEARLY FULLY CLEAR SKIES NOW OVER ALL BUT THE FAR EASTERN EDGES OF THE CWA WHERE SOME LOW STRATUS LINGERS. PRE-DAWN TEMPERATURES ARE FAIRLY UNIFORM ACROSS THE CWA...WITH MOST AREAS LIKELY HEADING FOR LOWS SOMEWHERE BETWEEN 21-27. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRMED AN ACTIVE PATTERN ACROSS THE CONUS...WITH THE NEARLY VERTICALLY STACKED CLOSED LOW DEPARTING OVER THE WI AREA...WHILE OFF TO OUR SOUTHWEST...A CURRENTLY OPEN 500MB SHORTWAVE TROUGH WAS CENTERED NEAR THE CA/NV/UT/AZ BORDERS...WITH ONLY THE SLIGHTEST HINT OF SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS IN BETWEEN THESE TWO PRIMARY LOWS. FORECAST-WISE TODAY...WHILE BY NO MEANS AS WINDY AS YESTERDAY...A HEALTHY NORTHWEST BREEZE OF 15-20 MPH WITH GUSTS 25+ MPH WILL PERSIST WELL INTO THE EARLY-MID AFTERNOON HOURS ACROSS ROUGHLY THE NORTHEAST 1/2 OF THE CWA THANKS TO EFFICIENT MIXING TO AROUND 850MB...BEFORE EASING MORE NOTICEABLY BETWEEN 3 PM AND SUNSET. ANY LINGERING/PRESUMABLY MINOR BLOWING SNOW ISSUES IN THE ORD AREA SHOULD CONTINUE TO ABATE WITH TIME. WIND SPEEDS ACROSS ROUGHLY THE SOUTHWEST 1/2 OF THE AREA WILL AVERAGE AT LEAST 5 MPH LIGHTER...AND ALSO START TO EASE UP SOONER ESPECIALLY THIS AFTERNOON AS A BROAD 1025MB RIDGE AXIS SETTLES INTO THE AREA. CLOUD-WISE...WHILE NEARLY THE ENTIRE AREA WILL START OUT WITH PLENTY OF SUNSHINE...THE AFTERNOON HOURS WILL BRING AT LEAST PARTLY CLOUDY SKIES TO MAINLY THE SOUTHWEST 1/2 OF THE CWA AS MID- HIGH CLOUDS SPREAD OVERHEAD DOWNSTREAM FROM THE SOUTHWEST CONUS LOW. THERE ARE SUGGESTIONS FROM THE LATEST HRRR RUNS THAT SOME SCATTERED LOW CLOUDS COULD ALSO INCREASE MAINLY THIS AFTERNOON IN SOME AREAS NORTH OF I-80...BUT WILL KEEP IT A MOSTLY SUNNY THEME HERE AT LEAST FOR NOW. AS FOR TEMPS...FOLLOWED THE 00Z NAM/05Z RAP SOLUTION RATHER CLOSELY...WHICH RESULTED IN A 1-3 DEGREE UPWARD NUDGE FROM PREVIOUS FORECAST...NOW RANGING FROM LOW 30S FAR NORTH...MID 30S CENTRAL...LOW 40S SOUTH MAINLY KS ZONES. ITS WORTH NOTING THAT THE 06Z NAM CAME IN COLDER FOR NORTHWEST COUNTIES...BUT THIS APPEARS TO BE A RESULT OF AN OVERDONE MODEL- INITIALIZED SNOW FIELD. THAT BEING SAID...CONFIDENCE IN TEMPS ISN/T QUITE AS HIGH ESPECIALLY FOR THE ORD AREA...WHERE A LIGHT COATING OF SNOW FROM YESTERDAY ALONG WITH A WIND DIRECTION BLOWING OFF OF THE DEEPER SNOW COVER OVER THE SANDHILLS COULD WORK TO HOLD THINGS DOWN A BIT. THIS EVENING/TONIGHT...CONFIDENCE REMAINS HIGH THAT THE ENTIRE CWA REMAINS PRECIPITATION-FREE...BUT THINGS DEFINITELY START TO TURN MORE INTERESTING A FEW COUNTIES TO OUR SOUTH...AS THE AFOREMENTIONED SOUTHWESTERN CONUS MID LEVEL SHORTWAVE TROUGH STARTS CLOSING OFF A BIT AS IT HEADS EAST INTO NM. FORCING DOWNSTREAM FROM THIS WAVE WILL SPREAD DECENT CHANCES FOR AT LEAST LIGHT ACCUMULATING SNOW INTO MAINLY THE SOUTHWEST 1/4 OF KS ESPECIALLY AFTER MIDNIGHT. WHILE A CONSENSUS OF VARIOUS MODELS SUCH AS THE NAM/ECMWF/4KM WRF-NMM KEEPS ANY OF THIS SNOW AT LEAST 80 MILES SOUTH OF THE FAR SOUTHERN CWA...THE NEW 06Z GFS HAS SUDDENLY TRENDED SLIGHTLY FARTHER NORTH...BRINGING AT LEAST A DUSTING OF SNOW WITHIN ROUGHLY 20 MILES OF FAR SOUTHERN ROOKS/OSBORNE COUNTIES. FOR NOW WILL DISCOUNT THIS RUN AS A NORTHERN OUTLIER AND STAND FIRM THAT THIS SYSTEM WILL NOT BE AN ISSUE FOR OUR CWA...AND BRING ONLY A PERIOD OF PARTLY/MOSTLY CLOUDY SKIES TO MAINLY OUR SOUTHERN COUNTIES. AT THE SURFACE TONIGHT...INITIALLY FAIRLY LIGHT/VARIABLE WINDS NEAR THE RIDGE AXIS WILL TAKE ON A SLIGHTLY STEADIER SOUTHWESTERLY COMPONENT LATE IN THE NIGHT IN RESPONSE TO A SUBTLE PASSING TROUGH AXIS. GIVEN THESE LIGHT WESTERLY BREEZES AND ALSO A FAIR AMOUNT OF PASSING CLOUD ESPECIALLY SOUTH...GENERALLY RAISED LOW TEMPS 2-4 DEGREES FROM PREVIOUS GRIDS...WITH ALL BUT FAR NORTHWESTERN AREAS HOLDING UP GENERALLY 17-22. TUESDAY DAYTIME...IN A CONTINUATION FROM LATE WED NIGHT ACCUMULATING SNOW WILL CONTINUE TO OUR SOUTH...TRACKING EASTWARD MAINLY ALONG/SOUTH OF THE KS/OK BORDER...AS THE PRIMARY 500MB SHORTWAVE ENDS UP OVER SOUTHERN/WESTERN OK BY DAYS END. AGAIN THOUGH...NO LOCAL IMPACT ANTICIPATED OTHER THAN MORE MID-HIGH CLOUD OVER KS ZONES VERSUS NEB ZONES. AT THE SURFACE...HIGH PRESSURE CENTERED TO THE WEST WILL DRIVE A WESTERLY DOWNSLOPE WIND COMPONENT ACROSS THE ENTIRE CWA...AND HAVE INCREASED SUSTAINED SPEEDS CLOSER TO 15 MPH WITH HIGHER GUSTS MAINLY FOR THE NORTHERN 1/2 OF THE CWA. ASSUMING THAT SUNSHINE IS FAIRLY PLENTIFUL IN MOST AREAS...AND GIVEN SLIGHT LOW LEVEL WARMING VERSUS MONDAY...SEE LITTLE REASON WHY THIS DOWNSLOPE WIND WON/T BRING A DECENT BOOST IN HIGH TEMPS...AND HAVE RAISED HIGHS GENERALLY 2-4 DEGREES FROM PREVIOUS FORECAST...ESPECIALLY IN EASTERN AREAS FARTHEST REMOVED FROM THE WESTERN/NORTH CENTRAL NEB SNOW FIELD. THIS NOW YIELDS HIGHS IN THE MID-UPPER 40S MOST AREAS...EXCEPT LOW 40S FAR NORTHWEST. TUESDAY NIGHT...THE SOUTHERN CONUS SHORTWAVE TROUGH TREKS EAST INTO THE AR/TN AREA...HELPING TRANSITION THE FLOW OVER THE CENTRAL PLAINS TO MORE PRONOUNCED NORTHWESTERLY...BUT WITH NO IMPACTFUL DISTURBANCES. ALTHOUGH A DECENT BATCH OF MID LEVEL CLOUDS COULD SAG SOUTHWARD ACROSS THE CWA...NOT EVEN EXPECTING FLURRIES AT THIS TIME. AT THE SURFACE...A LIGHT BUT STEADY 5-10 MPH WESTERN COMPONENT SHOULD AGAIN HELP KEEP TEMPS FROM FALLING TOO FAR...AND NUDGED UP PREVIOUS LOWS VERY SLIGHTLY...KEEPING MOST PLACES UP BETWEEN 21-24 DEGREES. WEDNESDAY...DRY NORTHWESTERLY FLOW ALOFT PERSISTS...AS THE LOCAL AREA REMAINS DOWNSTREAM FROM A LOW AMPLITUDE/CLIPPER-TYPE SHORTWAVE TROUGH SLIPPING OUT OF CANADA TO THE DAKOTAS/MN BORDER AREA BY DAYS END. UNDER GENERALLY PARTLY CLOUDY SKIES...A CONTINUED DOWNSLOPE WESTERLY WIND AND WARMER AIR EVIDENT ABOVE THE SURFACE AT 850MB SHOULD CONTINUE THE WARMING TREND FROM TUESDAY...AND HAVE MADE A VERY SLIGHT UPWARD NUDGE TO PREVIOUS HIGHS WITH MOST OF THE CWA INTO THE 50-53 RANGE...EXCEPT COOLER MID-UPPER 40S MAINLY IN OUR FAR NORTH/NORTHWEST FRINGES WHERE THE SNOW FIELD COULD STILL POSSIBLY EXERT SOME INFLUENCE. THE OVERALL BIGGEST CHANCE TO WEDNESDAY INVOLVED WIND SPEEDS...WHICH WERE UPPED AT LEAST 6-8 MPH FROM PREVIOUS GRIDS INTO BREEZY TERRITORY...AND NOW EXPECT SEVERAL HOURS OF SUSTAINED WEST-NORTHWEST SPEEDS 15-20 MPH WITH SOME HIGHER GUSTS. FORTUNATELY FOR POSSIBLE FIRE WEATHER CONCERNS...RELATIVE HUMIDITY VALUES ARE FORECAST TO FALL NO LOWER THAN THE UPPER-20S PERCENT...AND THIS IS ONLY IN A SMALL PART OF KS ZONES. WEDNESDAY NIGHT...THE AFOREMENTIONED NORTHERN PLAINS CLIPPER-SYSTEM DIVES DOWN MAINLY INTO IA/WI...WHILE AT THE SURFACE THE LEADING EDGES OF A MODEST COLD FRONT WILL ENTER THE LOCAL AREA. ALTHOUGH THE ORIENTATION OF THE UPPER JET ON THE WESTERN SIDE OF THIS DISTURBANCE ALONG WITH SOME MID LEVEL RH PROGS FROM MODELS SUCH AS THE 06Z NAM SUGGEST THAT A FEW FLURRIES MIGHT NOT BE OUT OF THE QUESTION FOR PARTS OF THE CWA...WILL KEEP ALL PRECIP MENTION OUT FOR NOW WITH POSSIBLY SLIGHTLY BETTER FLURRY CHANCES HOLDING OFF UNTIL THE THURS DAYTIME HOURS. MADE VERY LITTLE CHANGE TO LOW TEMPS WITH MID-UPPER 20S ALL AREAS. .LONG TERM...THURSDAY THROUGH SUNDAY...AT THE ONSET OF THE EXTENDED PERIODS...100KT TO 120KT JET H3 JET STREAKS WILL NOSE SOUTH FM ALBERTA ACROSS THE EASTERN SLOPES OF THE NORTHERN ROCKIES CARVING A TROUGH ACROSS THE EASTERN TWO THIRDS OF THE CONUS. IN A NORTHWEST FLOW REGIME ACROSS THE CENTRAL PLAINS...COLD AIR WILL BACK IN FM THE NORTHEAST WITH THE MAIN THERMAL TROUGH ORIENTED FM ONTARIO THRU THE GREAT LAKES REGION. ENERGY TRANSLATING SOUTHEAST THRU FLOW AND A PUSH OF COLD AIR SOUTH THURSDAY COULD GENERATE SNOW FLURRIES IN OUR NORTHERN ZONES. FRIDAY WILL SEE A REINFORCING SHOT OF COLD AIR AS A STRONGER JET STREAK DIVES SOUTH ALONG THE FRONT RANGE OF THE ROCKIES AND ADDITIONAL SHORTWAVE ENERGY TRANSLATES ON THE WESTERN EDGE OF THE TROUGH WHICH ULTIMATELY FURTHER DEEPENS TO THE TROUGH ACROSS CENTRAL AND EASTERN CONUS. CURRENTLY HAVE FLURRIES IN THE FORECAST ON FRIDAY AND THIS IS STILL WARRANTED WITH FROPA/UPPER DYNAMICS. TEMPS WILL TREND COLDER THURSDAY...CLOSER TO SEASONAL NORMALS...AND WILL DROP FURTHER FRIDAY WITH STRONGER COLD FRONT. A COLD SURFACE HIGH PRESSURE SYSTEM WILL SETTLE ACROSS THE CENTRAL PLAINS BEHIND THE FRONT FRIDAY NIGHT...WHICH WILL RESULT IN TEMPS IN THE TEENS FOR LOWS. AFTER A COLD COUPLE OF DAYS FOR THE END OF THE WORKWEEK...THE WEATHER OVER THE WEEKEND TRENDS WARMER. THE SFC RIDGE AXIS SLIDES SOUTHEAST ON SATURDAY...ALLOWING FOR RETURN FLOW...AND ALOFT...THE UPPER TROUGH DEPARTS EASTWARD AND HEIGHTS BEGIN TO RISE ACROSS THE CENTRAL PLAINS. BY SUNDAY THE RIDGE WHICH WAS OVER THE ROCKIES SATURDAY REACHES THE INTERIOR CONUS..AND WARMER AIR SPREADS EASTWARD. SUNDAY IS LOOKING LIKE THE WARMEST OF THE EXTENDED PERIODS WITH HIGHS IN THE 40S FOR THE MOST PART AND 50S MAY NOT BE OUT OF THE QUESTION. && .PREV DISCUSSION... /ISSUED 1050 PM CST SUN FEB 10 2013/ AVIATION...06Z KGRI TAF. STRONG NORTHWEST WIND WILL BE THE PRIMARY CONCERN FOR THE FIRST SEVERAL HOURS OF THE FORECAST...THEN SUBSIDE SOMEWHAT BY SUNRISE...BUT CONTINUE TO BE BRISK INTO MONDAY. CEILINGS WILL BE SCATTERING AND COULD FLUCTUATE BETWEEN VFR AND MVFR CEILING FOR THE FIRST HOUR OR TWO AS AN AREA OF LOW PRESSURE CONTINUES TO PULL NORTHEAST...BUT SHOULD BE PRIMARILY WITHOUT A CEILING FROM THE GET GO. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...FAY AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
457 AM MST MON FEB 11 2013 .AVIATION... 12Z TAF CYCLE A CHALLENGING DAY LIKELY FOR AVIATION AS TWO SURFACE FRONTS AND AN UPPER LEVEL LOW CONVERGE OVER THE AREA. CONFIDENCE ON THE TIMING OF THE MAIN IMPACT FEATURES IS MODERATE AS VARIOUS SHORT-TERM MODEL GUIDANCE IS STILL CONFLICTING. THE LATEST RUC AND HRRR SUGGEST A RATHER POTENT SNOW BAND WILL SLIDE EAST TODAY MUCH EARLIER THAN THE MET/MAV MOS GUIDANCE...SO HAVE DECIDED TO BRING IN THE FEATURE OVER CENTRAL NM FOR KABQ/KSAF FASTER THAN PREVIOUS TAFS. POTENTIAL FOR A SHORT DURATION OF IFR IS HIGH FOR SITES THAT ARE IMPACTED BY THIS BAND. WINDS WILL SHIFT DRAMATICALLY TO THE WEST AND NW WITH THIS FRONT...THEN DIMINISH DURING THE EVENING WHILE -SHSN LINGER OVER CENTRAL/WESTERN NM. MEANWHILE ACROSS THE EAST RETURN EASTERLY FLOW WILL INCREASE MOISTURE AND LOWER MID LEVEL CLOUD DECKS AFT 00Z. MODERATE TO LCL HEAVY SN IS EXPECTED AFT SUNSET WITH MUCH LONGER DURATION IMPACTS FOR KLVS/KTCC OVERNIGHT. GUYER && .PREV DISCUSSION...338 AM MST MON FEB 11 2013... AN UPPER TROUGH THAT DUG DEEPLY THROUGH UT ON SUNDAY APPEARS TO BE FORMING A CLOSED LOW PRESSURE CIRCULATION AS IT DROPS INTO NORTHERN AZ EARLY THIS MORNING. MODELS AGREE THAT THIS FEATURE WILL PASS EASTWARD OVER NM ALONG AND A LITTLE NORTH OF INTERSTATE 40 TONIGHT...THEN IT WILL EXIT GRADUALLY EASTWARD THROUGH THE TX PANHANDLE ON TUESDAY. STEADY SNOW THAT HAS BEEN FALLING ON THE WEST SLOPE OF THE CO ROCKIES SHOULD DROP SOUTHWARD INTO NW NM TODAY AND EXTEND SOUTHWARD ALONG THE NM CONTINENTAL DIVIDE. A COLD FRONT WILL PROVIDE A FOCUS FOR PRECIP AS IT PUSHES SOUTHEASTWARD THROUGH WESTERN NM TODAY...THEN THROUGH CENTRAL PARTS OF THE STATE THIS EVENING...AND THROUGH THE PLAINS EARLY TUESDAY MORNING. FOR WESTERN AND CENTRAL AREAS WE WILL CONTINUE WITH ONGOING HEADLINES FOR SNOW...BUT WILL UPGRADE THE JEMEZ MOUNTAINS AND UPPER RIO GRANDE VALLEY TO A WINTER STORM WARNING BASED ON THE TRACK OF THE LOW AND THE LATEST MODEL SNOW AMOUNTS. WILL ALSO ISSUE A WINTER WEATHER ADVISORY FOR THE WEST CENTRAL HIGHLANDS...SANTA FE METRO AREA AND LOWER CHAMA RIVER VALLEY FOR TONIGHT. LIKE THE JEMEZ AND UPPER RIO GRANDE VALLEY...THESE AREAS SHOULD SEE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING AS THE COLD FRONT CROSSES FROM THE WEST...THEN SOME LINGERING SNOW LATE TONIGHT AS THE UPPER LOW CROSSES. ASIDE FROM THE WESTERLY UPSLOPE FLOW EVENT ALONG AND WEST OF THE CENTRAL MOUNTAIN CHAIN...AN EASTERLY UPSLOPE EVENT IS EXPECTED EAST OF THE SANGRE DE CRISTOS TONIGHT. THEN...WRAP AROUND MOISTURE WILL KEEP SNOW FALLING ACROSS THE EAST CENTRAL AND NORTHEAST PLAINS ON TUESDAY. THE 00Z GFS AND NAM BOTH DEPICT WARNING CRITERIA SNOW AMOUNTS ACROSS THE PLAINS...BUT THE ECMWF HAS LIGHTER AMOUNTS DESPITE THE SAME COVERAGE AREA OF PRECIP. GIVEN THIS UNCERTAINTY...WE OPTED TO EXPAND THE WINTER STORM WATCH FOR NE NM SOUTHEASTWARD ACROSS QUAY...CURRY AND ROOSEVELT COUNTIES. ALSO...MODEL AGREEMENT ON THE TRACK OF THE LOW AND EASTERLY UPSLOPE FLOW OVERNIGHT GAVE US ENOUGH CONFIDENCE TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE EAST SLOPES OF THE SANGRES AND RATON PASS. UNCERTAINTY REMAINS ABOUT HOW MUCH SNOW WILL FALL ACROSS CENTRAL AND SE NM. MODELS AGREE ON SURPRISINGLY LIGHT QPF AROUND ABQ...THE SANDIAS AND THE CENTRAL HIGHLANDS. THEY TYPICALLY DONT RESOLVE THE NARROW SANDIA AND MANZANO MOUNTAINS VERY WELL...AND THESE RANGES TEND TO WRING OUT SNOW AS COLD FRONTS CROSS FROM THE WEST...SO WE ARE ALSO ISSUING A WINTER WEATHER ADVISORY FOR THE SANDIAS AND MANZANOS WITH THIS MORNINGS FORECAST PACKAGE. WILL LET THE DAY SHIFT DECIDE WHAT TO DO WITH THE ALBUQUERQUE METRO AREA AND CENTRAL HIGHLANDS...SINCE MODELS AGREE ON LIGHTER PRECIP IN THESE AREAS...PERHAPS TOO LIGHT FOR ANY HEADLINES. PRECIP WILL TAPER OFF QUICKLY LATE TUESDAY AFTERNOON. AFTER HIGH TEMPERATURES 12 TO 20 DEGREES BELOW NORMAL ON TUESDAY...TEMPERATURES WILL WARM BUT REMAIN BELOW NORMAL UNDER DRY NW FLOW ALOFT WEDNESDAY. AN UPPER TROUGH WILL DIVE SOUTHEASTWARD ALONG THE FRONT RANGE OF THE ROCKIES THURSDAY THROUGH FRIDAY. THE POTENTIAL EXISTS FOR A FEW INCHES OF SNOW ACCUMULATION ALONG AND EAST OF THE NORTHERN AND CENTRAL MOUNTAINS MAINLY THURSDAY NIGHT AND FRIDAY. 44 .FIRE WEATHER... AN ACTIVE WX SCENARIO WILL CONTINUE THRU THIS WEEK WITH BOUTS OF SNOW...COLD...AND WIND...THEN MILDER TEMPS AND DRY BREEZY CONDITIONS OVER THE WEEKEND. THE PACIFIC COLD FRONT AND ASSOCIATED SNOW BAND IS POSITIONED OVER AZ AND FAR WESTERN NM...WHILE THE PLAINS FRONT IS BACKING INTO THE NE CORNER. AN UPPER LEVEL WAVE WILL SLIDE OVER THESE TWO FRONTS AS THEY CONVERGE OVER NM ALLOWING FOR WIDESPREAD SNOW FIRST OVER THE WEST TODAY/TONIGHT THEN OVER THE EAST TONIGHT/ TUESDAY. MUCH NEEDED ADDITIONAL SNOW ACCUMS OVER THE HIGHER TERRAIN WILL CONTINUE ADDING TO OUR BELOW NORMAL SNOWPACK. TEMPS WILL BE COLD WITH THIS WINTER SYSTEM BOTH TODAY AND TUESDAY... WITH SLIGHTLY MILDER CONDITIONS FOR WEDNESDAY. MIN RH VALUES WILL BE QUITE HIGH AS A RESULT OF THE SNOW MONDAY/TUESDAY AS WELL AS WEDNESDAY DESPITE VERY DRY AIR WORKING INTO THE REGION BEHIND THE WAVE. WIDESPREAD VERY GOOD TO EXCELLENT MAX RH RECOVERIES ARE ALSO ON TAP. VENT RATES WILL START OUT VERY GOOD TO EXCELLENT TODAY FOR CENTRAL NM WITH SW FLOW AHEAD OF THE WAVE...DECREASE TUESDAY...THEN BECOME POOR AREAWIDE BY WEDNESDAY AS WINDS ALOFT WEAKEN. ANOTHER WAVE WILL SLIDE SOUTH OVER THE AREA THURSDAY AND REINFORCE THE COLD AIR AND INCREASE LOW LEVEL MOISTURE ONCE AGAIN. MODELS DISAGREE ON PRECIP DEVELOPMENT OVER THE NORTHEAST WITH THIS SYSTEM. A RIDGE IS THEN ANTICIPATED TO MOVE SLOWLY OVER THE REGION LATE FRIDAY INTO THE WEEKEND. STRONG TEMP INVERSIONS WILL BE GREATEST FRIDAY AND SATURDAY MORNING...LEADING TO POOR VENT RATES. BREAK DOWN OF THIS RIDGE SUNDAY/MONDAY MAY LEAD TO CRITICAL FIRE WX CONDITIONS FOR EASTERN NM IN ASSOCIATION WITH A MID LEVEL DRY SLOT. GUYER && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES...NMZ528>532-534>536. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM MST TUESDAY FOR THE FOLLOWING ZONES...NMZ507-517-518-521. WINTER WEATHER ADVISORY UNTIL 6 AM MST TUESDAY FOR THE FOLLOWING ZONES...NMZ501-504>506. WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR THE FOLLOWING ZONES...NMZ502-503-510>516-527. && $$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
950 AM EST MON FEB 11 2013 .SYNOPSIS... A WARM FRONT WILL CONTINUE MOVING NORTHWARD THROUGH THE AREA TODAY. A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST TO OUR SOUTH... THEN WEAK HIGH PRESSURE WILL MOVE IN LATE TONIGHT THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONT AND AFFECT THE AREA ON WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY/... AS OF 950 AM MONDAY... REST OF TODAY: MAIN CONCERNS THIS MORNING ARE DEALING WITH THE DEPARTING RAIN... WIDELY VARYING TEMPS... AND WIND. WEDGE REGIME REMAINS WELL-ENTRENCHED OVER THE FAR NRN AND NW PIEDMONT... BISECTING THE TRIAD REGION WITH 9 AM TEMPS IN THE UPPER 50S IN ASHEBORO WHILE LOWER 40S HOLD AT LEXINGTON WITH FOG/STRATUS AND VERY LIGHT TO CALM AIR. THE 12Z GSO SOUNDING SHOWS A FORMIDABLE STABLE LAYER (+4C DIFFERENTIAL FROM SURFACE TO WARM NOSE ALOFT) WITH DEEP SATURATION... AND EVEN OUTSIDE OF THIS DEFINED WEDGE... DESPITE THE MILDER TEMPS IN THE 50S... THE LOW LEVELS (UNDER 900 MB) REMAIN NEUTRAL TO SLIGHTLY STABLE AS NOTED BY RECENT AMDAR AIRCRAFT SOUNDINGS NEAR RDU. WINDS HERE ARE BEGINNING TO PICK UP OUT OF THE SOUTH AND SW THOUGH... INDICATING THAT IMPROVED LOW LEVEL MIXING IS IMMINENT. THE WIDESPREAD LIGHT RAIN IS ON ITS WAY OUT A BIT MORE QUICKLY THAN EARLIER ANTICIPATED... HOWEVER WITH BLENDED TPW IMAGERY SHOWING PRECIP WATER VALUES OVER 200 PERCENT OF NORMAL ACROSS THE ENTIRE REGION... THE RISK OF PATCHY SHOWERS WILL REMAIN FOR ANOTHER SEVERAL HOURS AS THE MOIST COLUMN WILL STAY VULNERABLE TO EVEN SUBTLE FORCING FOR ASCENT. WILL HOLD ONTO SMALL POPS MAINLY S/E OF THE TRIAD INTO THE AFTERNOON. LOW CLOUDS SHOULD HOLD IN EVERYWHERE UNTIL MID AFTERNOON WITH THE CONTINUED LOW-MID LEVEL FLOW FROM THE SW ELIMINATING THE POTENTIAL FOR SIGNIFICANT DOWNSLOPE DRYING UNTIL LATE... WHEN THE MID LEVEL PERTURBATION NOW OVER NW NC MOVES OFF THE COAST. TEMPS ARE ALWAYS TOUGH TO GAUGE IN THESE WEDGE SITUATIONS ESPECIALLY WHEN THERE IS NO LONGER A FEED OF LOW LEVEL DRY AIR TO MAINTAIN THE STABLE POOL. ALL FINE-RESULTION GUIDANCE INCLUDING THE LOCAL WRF AND HRRR FAVORS A MIXING-OUT OF THE REMAINING WEDGE OVER OUR NW CWA BY EARLY AFTERNOON... ALTHOUGH THE ABUNDANT THICK CLOUDS FOR MUCH OF THE DAY WILL CUT DOWN ON WARMING ALL ACROSS THE AREA. NEVERTHELESS.... ANOMALOUSLY WARM THICKNESSES WILL RISE FURTHER THIS AFTERNOON... AND STILL EXPECT HIGHS IN THE MID 60S TO NEAR 70 OVER MUCH OF THE CWA EXCEPT FOR NEAR 60 IN THE NW CORNER. SINCE WE WON`T FULLY MIX UP BEYOND 900 MB UNTIL LATE IN THE DAY... WHEN THE 50-60 KT LOW LEVEL JET WILL HAVE EXITED... OUR WIND GUSTS WILL REMAIN WELL BELOW ADVISORY THRESHOLD... YET WE SHOULD STILL SEE GUSTS BECOME MORE FREQUENT AND HIGHER THIS AFTERNOON ESPECIALLY OUTSIDE THE DECAYING WEDGE REGION. GUSTS SHOULD EXCEED 20-25 KTS PERIODICALLY. -GIH TONIGHT AND TUESDAY: SURFACE COLD FRONT IS EXPECTED TO QUICKLY MOVE ACROSS THE AREA LATE TODAY INTO THIS EVENING WITH THE LOW LEVEL AIRMASS COMPLETELY SCOURING OUT AS IT MOVES THROUGH. HOWEVER... WE WILL KEEP A LEAST SOME MID AND HIGH LEVEL CLOUD COVER... ESPECIALLY ACROSS THE SOUTH.... WHILE THE SURFACE FRONT STALLS TO THE SOUTH OF THE AREA. EXPECT LOW TEMPS TONIGHT TO RANGE FROM AROUND 40 NW TO UPPER 40S SE... WITH A WEST TO NORTHWESTERLY BREEZE AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. TUESDAY WILL START OFF WITH QUITE WEATHER. HOWEVER... A SOUTHERN STREAM DISTURBANCE WILL BEGIN APPROACHING THE REGION FROM THE SOUTHWEST ON TUESDAY... SPREADING MORE CLOUDS INTO THE AREA AND PERHAPS SOME LIGHT RAIN ACROSS THE FAR SOUTHWEST LATE IN THE DAY. HIGH TEMPS ARE AGAIN EXPECTED TO BE ABOVE NORMAL AS THE SYSTEM APPROACHES FROM THE SOUTH AND SURFACE WINDS QUICKLY SWING BACK AROUND TO WSW TO SOUTHWESTERLY IN ADVANCE OF THE DISTURBANCE. THUS... WILL GO WITH HIGHS IN THE LOWER TO MID 60S. -BSD && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 305 AM MONDAY... TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... NEXT LOW PRESSURE SYSTEM IN THE ACTIVE SOUTHERN STREAM PROJECTED TO TRAVERSE THE SOUTHERN PLAINS INTO THE LOWER MS VALLEY LATE TUE-TUE NIGHT. THIS WEATHER SYSTEM WILL INDUCE THE FORMATION OF A SURFACE LOW ON THE STALLED FRONT OVER THE NORTHERN GULF COAST BY LATE TUESDAY. THE 00Z GFS TAKES THIS SURFACE WAVE NEWD UP THE SOUTHERN APPALACHIANS THEN EWD ACROSS THE NC-VA PIEDMONT. 00Z ECMWF FITS INTO THE CLASSICAL MODEL WITH THE WAVE PROGRESSING ENE ALONG A STALLED SURFACE BOUNDARY ACROSS SOUTHERN AL-SOUTHERN GA THEN OFF THE CAROLINA COASTS WHERE IT INTENSIFIES IN THE FAVORABLE BAROCLINIC ZONE CAUSED BY THE GULF STREAM. INCREASING SLY FLOW AHEAD OF THE SURFACE LOW WILL CAUSE AN OVERRUNNING PRECIP EVENT ACROSS CENTRAL NC LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING. THE INCREASING MOISTURE WILL ALSO BE LIFTED BY NOT ONLY THE MID-UPPER LEVEL S/W BUT ALSO FROM A FAVORABLE JET CONFIGURATION WITH CENTRAL NC IN THE NOSE OF 140+ KT JET. THUS...EXPECT WIDESPREAD RAIN TO OVERSPREAD CENTRAL NC EARLY WED AND CONTINUE WELL INTO THE AFTERNOON. THE PRECIP AND OVERCAST SKIES WILL RESULT IN BELOW NORMAL TEMPS WITH MAX TEMPS HOLDING INT EH 40S ACROSS MOST OF THE PIEDMONT...AND THE LOWER 50S IN THE FAR SOUTH-SE. WEDNESDAY NIGHT...S/W CROSSES THE REGION IN THE EVENING THEN EXITS THE COAST. DRIER WNW FLOW BEHIND THIS SYSTEM AS WELL AS SUBSIDENCE WILL AID TO DISSIPATE CLOUD COVERAGE NW-SE DURING THE OVERNIGHT HOURS. RESIDUAL MOISTURE MAY RESULT IN SOME AREAS OF FOG BUT CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO INTRODUCE IN THE FORECAST AS MAY BE ENOUGH MIXING TO PREVENT FOG FROM DEVELOPING. MIN TEMPS MID-UPPER 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 305 AM MONDAY... THURSDAY INTO FRIDAY...RELATIVELY TRANQUIL WEATHER PATTERN ANTICIPATED AS BROAD TROUGH OVER THE EASTERN U.S. WILL CAUSE A WLY FLOW THROUGH THE COLUMN OVER CENTRAL NC. THIS USUALLY YIELDS DRY WEATHER WITH MILD TEMPS. LOW LEVEL THICKNESSES A SHADE ABOVE NORMAL THU AND NEAR NORMAL FRI BUT WLY FLOW USUALLY ADDS ADDITIONAL WARMING. AFTERNOON TEMPS IN THE 50S BOTH DAYS...APPROACHING 60 N THE FAR SOUTH FRI. BROAD UPPER TROUGH OVER EASTERN U.S. WILL UNDERGO AMPLIFICATION SATURDAY INTO SUNDAY AS PACIFIC ENERGY IS SHUNTED WELL NWD INTO ALASKA AND BRITISH COLUMBIA IN RESPONSE TO A STOUT UPPER LEVEL RIDGE OVER THE WESTERN U.S. THIS ENERGY DIVES ON SEWD INTO THE NORTH CENTRAL U.S. INITIATING THE AMPLIFICATION OF THE TROUGH. THIS WILL CAUSE A MODIFIED ARCTIC AIR MASS TO SPREAD SEWD ACROSS MUCH OF THE EASTERN U.S. THIS WEEKEND. THE LEADING EDGE OF THIS COLDER AIR WILL SPREAD ACROSS CENTRAL NC FRI NIGHT INTO SATURDAY. MODEL GUIDANCE CONTINUES TO EXHIBIT POSSIBLE SURFACE CYCLOGENESIS ASSOCIATED WITH THIS AMPLIFICATION OFF THE EASTERN SEABOARD IN VICINITY OF THE MID ATLANTIC COAST NWD TO NEW ENGLAND. CONSIDERING THE STRENGTH OF THE DISTURBANCES ALOFT...MAY BE ENOUGH TO TRIGGER SCATTERED SHOWERS ACROSS CENTRAL NC SATURDAY INTO SATURDAY EVENING. PARTIAL THICKNESSES AND FORECAST GFS BUFKIT SOUNDINGS SUGGEST THAT SNOW SHOWERS WOULD BE FAVORED OVER RAIN SHOWERS BUT MODELS MAY BE COOLING OFF THE COLUMN TOO QUICKLY. SINCE WE ARE TALKING ABOUT DAY 6...PREFER TO MAINTAIN A SLIGHT CHANCE POP FOR NOW AND KEEP PRECIP ALL LIQUID. HOWEVER DID BUMP UP CLOUDINESS A TAD AND LOWERED MAX TEMPS SATURDAY 2-3 DEGREES FROM THE PREVIOUS FORECAST. MAX TEMPS SATURDAY IN THE 40S TO NEAR 50 SOUTHEAST. IF PRECIP MORE EXTENSIVE THAN CURRENT THINKING...MAX TEMPS COULD BE TOO WARM BY AS MUCH AS 5-6 DEGREES. BULK OF COLDER AIR WILL SETTLE OVER THE REGION SUNDAY WITH MAX TEMPS 10-14 DEGREES BELOW NORMAL. MIN TEMPS SUN MORNING IN THE 20S. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 640 AM TUESDAY... 24 HOUR TAF PERIOD: ADVERSE AVIATION CONDITIONS EXPECTED TODAY... WITH SUB-VFR CONDITIONS AND GUSTY WINDS POSSIBLE. LIGHT RAIN AND DRIZZLE ARE FILLING IN ACROSS CENTRAL NC AGAIN THIS MORNING... WITH ALONG WITH A MORE DEFINED IN-SITU COLD AIR DAMMING WEDGE AIRMASS PARKED ACROSS THE AREA. AT KFAY THE WARM FRONT HAS SURGE TO THE NORTH OF THE AREA... WITH THE CAD BOUNDARY GENERALLY EXTENDING FROM JUST SOUTH OF KEXX (LEXINGTON) EASTWARD TO THE NORTHERN COASTAL PLAIN. LOW CIGS WITH GENERALLY LIGHT AND VARIABLE RAIN ARE COMMON ON THE NORTHERN SIDE OF THE BOUNDARY... WITH SOUTHERLY WINDS IN THE 10 TO 15 KT RANGE... WITH GUSTS OF UP TO 20-25 KTS POSSIBLE SOUTH OF THE BOUNDARY WITH GENERALLY MVFR CIGS (WITH RAIN STILL). THIS LATEST AREA OF RAIN IS EXPECTED TO MOVE ACROSS MOST OF THE AREA OVER THE NEXT 3-5 HOURS. THIS MAY HELP DELAY THE EROSION OF THE CAD AIRMASS AT KRDU AND KRWI BY A FEW HOURS. THUS... HAVE DELAYED CONDITIONS IMPROVING AND ARRIVE OF THE GUSTY WINDS... AND THUS EXTENDED THE THREAT OF LLWS AS SOUTHWESTERLY WINDS OF 40-45 KTS A COUPLE THOUSAND FEET OFF OF THE SURFACE WILL CONTINUE ACROSS CENTRAL NC THROUGH EARLY AFTERNOON. THUS... BY 16Z OR SO EXPECT WINDS TO INCREASE AT KRDU AND KRWI OUT OF THE SOUTHWEST... WITH GUSTS IN THE 20 TO 25 KT RANGE FOR THE AFTERNOON. FURTHER WEST WE MAY NOT SEE THE STABLE AIRMASS BREAK UNTIL EARLY TO MID AFTERNOON. THUS... HAVE PUSHED BACK THE TIMING A BIT... WITH MVFR CIGS NOT EXPECTED UNTIL AFTERNOON... ALONG WITH THE GUSTY SOUTHWESTERLY WINDS. AT KFAY... EXPECT WE WILL SEE THE WIND GUSTS IN THE 20 TO 25 KT RANGE... WITH EVEN 30 KTS NOT OUT OF THE QUESTION IF CIGS INCREASE ENOUGH BEFORE THE CORE OF THE LOW LEVEL JET SHIFTS TO THE EAST THIS AFTERNOON. OTHERWISE EXPECT ON AN OFF RAIN MOST OF THE DAY (FOR KFAY)... WITH GENERALLY MVFR CIGS... TO AT TIMES IFR. A COLD FRONT WILL MOVE ACROSS THE AREA LATE IN THE DAY AND SCOUR OUR ANY LINGERING LOW LEVEL CLOUD COVER.... ALLOWING A RETURN TO VFR CONDITIONS BY AROUND 03Z OR SO. VFR CONDITIONS ARE THEN EXPECTED TO CONTINUE FOR THE REST OF THE TAF PERIOD. LOOKING AHEAD: VFR CONDITIONS SHOULD PREVAIL THROUGH TUESDAY EVENING BUT THEN A SHORTWAVE SYSTEM COULD BRING SUB VFR CONDITIONS FOR WEDNESDAY AND WEDNESDAY NIGHT. CONDITIONS ARE EXPECTED TO RETURN TO VFR AND HOLD THERE THROUGH THE REST PERIOD. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BSD SHORT TERM...WSS LONG TERM...WSS AVIATION...BSD
AREA FORECAST DISCUSSION
NWS TUCSON AZ
930 AM MST MON FEB 11 2013 .SYNOPSIS...A STRONG AND COLD STORM SYSTEM ACROSS NORTHWEST ARIZONA WILL TRACK ACROSS SOUTHEAST ARIZONA THIS AFTERNOON AND EVENING... RESULTING IN A CHANCE OF VALLEY RAIN AND POSSIBLY LOW ELEVATION SNOWFALL. COLD TEMPERATURES WILL PREVAIL THROUGH TUESDAY FOLLOWED BY DRY CONDITIONS AND A WARMING TREND WEDNESDAY THROUGH SUNDAY. && .DISCUSSION...WATER VAPOR IMAGERY SHOWS AN UPPER LOW OVER PORTIONS OF THE CENTRAL ROCKIES WITH THE TROUGH AXIS EXTENDING SOUTHWEST ACROSS NORTHWEST ARIZONA AND INTO EXTREME SOUTHEAST CALIFORNIA. THE NEXT IMPULSE WITH THIS SYSTEM THAT WILL BRING THE POTENTIAL FOR RAIN AND MOSTLY MOUNTAIN SNOW IS JUST ENTERING WESTERN ARIZONA AT THIS TIME. IR SATELLITE IMAGERY SHOWS A BAND OF EXTENSIVE CLOUDINESS EXTENDING FROM NORTHWEST NEW MEXICO AND ACROSS CENTRAL ARIZONA WITH THE CENTRAL AND EASTERN PORTIONS OF MY FORECAST AREA STILL CLOUD FREE. HOWEVER...TO THE WEST OVER EXTREME WESTERN AND CENTRAL PORTIONS OF PIMA COUNTY...MID LEVEL CLOUDS ARE CONTINUING TO DEVELOP AND THESE WILL MOVE EAST AND SOUTHEAST AS THE MORNING PROGRESSES. THIS MORNINGS KTWC SOUNDING REVEALED A CONTINUED DRY SOUNDING WITH PRECIPITABLE WATER VALUES VIRTUALLY IDENTICAL TO LAST EVENINGS SOUNDING WITH A VALUE THIS MORNING OF 0.19 INCHES. NEEDLESS TO SAY...THE AIRMASS HAS NOT MOISTENED QUITE AS MUCH AS WAS EXPECTED LAST EVENING. THE 00Z NAM SHOWED LESS THAN 10 PERCENT POP FOR THIS AFTERNOON FOR TUCSON...BUT 61 PERCENT POP BETWEEN 00Z AND 06Z THIS EVENING. HOWEVER...THE 12Z RUN OF THE NAM NOW SHOWS 27 PERCENT POP FOR TUCSON THIS AFTERNOON AND VIRTUALLY ZERO AFTER 00Z. IN ADDITION...THE HRRR (HIGH RESOLUTION RAPID REFRESH) MODEL SHOWS A BAND OF PRECIPITATION MOVING ACROSS THE TUCSON METRO AREA BETWEEN AROUND 3 PM TO 6 PM THIS AFTERNOON. THE GFS MOS POP SHOWS ABOUT A 30 PERCENT POP FOR THE MIDDLE TO LATTER PORTION OF THIS AFTERNOON. THE LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SHOW A BAND OF SHOWERS EXTENDING FROM THE MOGOLLON RIM AREA AND SOUTHWEST ACROSS THE PHOENIX METRO. ANOTHER BATCH OF PRECIPITATION IS MOVING ACROSS THE EXTREME SOUTHWESTERN PORTION OF ARIZONA EAST OF BLYTHE. CLOSER TO HOME...NOT MUCH ACTIVITY OVER MY FORECAST AREA...YET. THAT SAID...THE INHERITED 40 PERCENT POP FOR THIS AFTERNOON SEEMS REASONABLE...SO NO CHANGES ARE PLANNED TO THE POP FORECAST FOR THE REST OF TODAY. HOWEVER...WILL CONTINUE TO MONITOR SATELLITE AND RADAR TRENDS THROUGH THE REMAINDER OF THE MORNING AND INTO THE AFTERNOON AND WILL MAKE ADJUSTMENTS IF NEEDED. INHERITED SNOW AMOUNTS FROM THE NIGHT SHIFT WITH THIS SYSTEM ARE INDICATING AMOUNTS WELL BELOW ADVISORY CRITERIA WITH ABOUT 3 TO 5 INCHES OVER THE WHITE MOUNTAINS AND 2 TO 4 INCHES FOR THE SANTA CATALINA`S OF NORTHEAST PIMA COUNTY AND THE PINALENO`S OF GRAHAM COUNTY. THE TEMPERATURES AS OF 16Z (9 AM MST)...RANGE FROM THE UPPER 30S TO THE LOWER 40S AND THESE READINGS SEEM TO BE ON TRACK WITH EXPECTED AFTERNOON HIGHS...SO NO CHANGES PLANNED AT THIS TIME. && .AVIATION...CLOUDS INCREASING FROM NORTH TO SOUTH ACROSS SOUTHEAST ARIZONA TODAY. EXPECT SCT-BKN CLOUDS AT 5-8K FT AGL DEVELOPING AREAWIDE BETWEEN 11/17Z-11/20Z TODAY. MVFR CIGS/VSBYS AND MOUNTAIN OBSCURATIONS IN SHSN IN THE WHITE MOUNTAINS DEVELOPING AFT 11/17Z WITH SCT VALLEY SHRA/MOUNTAIN SHSN ELSEWHERE. SURFACE WIND LESS THAN 10 KTS THRU 11/14Z...THEN INCREASING SURFACE WIND...WITH SWLY/WLY SURFACE WIND AT 15-20 KTS AND GUSTS TO 20-30 KTS AFT 11/18Z. SURFACE WIND DIMINISHING AFT 12/03Z...AND GENERALLY LESS THAN 10 KTS BY 12/06Z. ELEVATED SURFACE WIND CONTINUING IN THE GILA RIVER VALLEY ON TUESDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A STORM SYSTEM WILL RESULT IN A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW SHOWERS TODAY AND TONIGHT...MAINLY FROM TUCSON EAST AND NORTHEAST. THIS SYSTEM WILL ALSO BRING STRONG AND GUSTY WINDS TODAY...CONTINUING IN THE GILA RIVER VALLEY TUESDAY. A WARMING TREND WILL THEN BEGIN ON WEDNESDAY...PERSISTING THROUGH SUNDAY. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
354 PM EST Mon Feb 11 2013 .NEAR TERM [through Tonight]... Thunderstorms continue as of 20 UTC along an outflow boundary that stretched from Fitzgerald, GA (FZG) to Bainbridge, GA (BGE) to Destin, FL (DTS). This outflow boundary has not moved much during the course of the day, likely due to largely boundary-parallel flow in the lowest 2km AGL. Meanwhile, GOES blended PWAT product shows a broad ribbon of 1.2 to 1.5" values near and just behind the slow-moving boundary - roughly 150-250% of normal across much of the Gulf coast and into the Carolinas. These ingredients taken together are favorable for flash flooding events due to training thunderstorms. As such, it is not surprising that we have had some flash flooding today - see the "Hydrology" section below for more information. The overall atmospheric pattern is not expected to change much overnight. The outflow boundary / deep convergence zone should shift gradually south into the evening hours, which should focus the majority of the thunderstorm activity in our area from 22-06z from around PAM-TVI. Meanwhile, a large area of moderate rain with embedded thunderstorms was developing from C/S AL west into LA. This area of rain was roughly on the broad nose of a newly developed low-level moisture transport maximum - currently focused into coastal Louisiana and Mississippi. The RAP projects that the ribbon of strongest moisture transport should develop northeast into our area by around 03z, with roughly similar PWAT values. Therefore, we anticipate that rain - heavy at times, with embedded storms - will redevelop across much of the NW half to two-thirds of our area this evening. Parts of our area remain in a "Slight Risk" of severe storms as of the 20 UTC SPC SWODY1. An isolated severe storm cannot be ruled out with some marginal mixed layer instability and effective shear around 45 knots lingering into the evening. && .SHORT TERM [Tuesday through Wednesday Night]... A more pronounced mid-upper level trough - currently evident on water vapor loops over the Desert Southwest - will dig ESE into the Southern Plains on Tuesday, and then eject into the Ohio River Valley on Tuesday Night. This evolution will allow for surface cyclogenesis on Tuesday near coastal Louisiana, with the low passing northwest of our area through central Alabama on Tuesday Night. With stronger height falls and QG convergence to the west of us on Tuesday, we should see a lull in the rain during the day. The better chances of rain are expected to arrive from Tuesday Night into Wednesday with the main trailing cold front. Portions of our area are in a "Slight Risk" on the latest SPC SWODY2 outlook for the possibility of storms moving in later in the period (Tuesday evening or overnight). The local confidence grids and the SPC SREF calibrated severe probabilities both indicate about a 15-20% chance of severe storms in the western two-thirds of our area in the 12-hour period centered on 12z Wednesday. CIPS analogs from SLU show about 5-10% probabilities, with about half the analogs with at least one severe weather report in our area. The combination of all of these probabilistic outlooks are in fairly good agreement, and are consistent with some isolated severe storms late Tuesday Night. Mean model MLCAPE on the ECMWF, GFS, and CAM models looks to be around 500 j/kg overnight with about 60-70 knots of deep layer shear. && .LONG TERM [Thursday through Monday]... Quieter weather arrives with surface high pressure and increasing subsidence in the wake of the cold front on Thursday and Friday. An amplifying longwave trough in the eastern CONUS on the weekend may provide a shot of colder air, although details still vary from model-to-model, and run-to-run. && .AVIATION [through 18z Tuesday]... Complex forecast for all TAF sites through the period with unsettled weather ahead of a slow moving surface front. Scattered to numerous showers and thunderstorms will be common around the area with MVFR most prevalent. Occasional IFR conditions will accompany the stronger storms through the evening, with MVFR and IFR prevailing overnight due to cigs and vsby near or below airport minimums. A repeat tomorrow, with perhaps more widespread showers and thunderstorms late in the day. && .MARINE... Unsettled weather pattern will remain through mid week with a chance of showers and thunderstorms, as well as breezy southerly winds each period. Winds will increase a bit ahead of a cold front Tuesday night and Wednesday, before switching to offshore on Thursday and diminishing into the weekend. && .FIRE WEATHER... An unsettled weather pattern with scattered to numerous showers and thunderstorms will continue at least through Wednesday. Drier conditions will return late in the week but we see no fire weather concerns at this time. && .HYDROLOGY... Significant rainfall has largely ended for this afternoon across the region. Observed and radar estimated rainfall totals show significant storm totals of 10 to 15 inches from Central Geneva County eastward through much of Houston County. Lower values of 5 to 8 inches were observed further east into parts of Southwestern Georgia in the last 24 hours. Given recent rains across Southeast Alabama and Southwest Georgia, little additional rainfall will be needed to cause flash flooding in these areas and a flash flood watch remains in effect through Tuesday morning. Higher end rainfall totals are expected once again on Tuesday evening through Wednesday across the area. Given the uncertainty with the exact placement of the heaviest rainfall with this next system, will delay any flash flood watches on this package. However, it is expected that additional flash flood watches will be needed across the area Tuesday night into Wednesday. Riverine flooding will become an increasing concern as local runoff is routed downstream from creeks and streams in Southeast Alabama. River gages north of a line from Enterprise Alabama to Abbeville Alabama appear to have crested with routed flow from these sites progressing down into the Choctawhatchee River system. Rises to near or in excess of minor flood stage is anticipated along the Choctawhatchee River from Geneva southward to Caryville into Friday given the current water already in the system. Flooding may also continue downriver toward Bruce but this would not occur until Saturday under present conditions. Rises on the Chipola River to minor flood stage can also be expected later this week as runoff progresses downstream from Southern Alabama. Additional riverine flooding, both in magnitude and coverage, will largely depend on the next 36 to 48 hours worth of rainfall. With soils already saturated in Southeast Alabama and a good portion of Southern Georgia, little additional rainfall will be absorbed there and will thus be converted into runoff, increasing river flood potential. River systems in South Central Georgia and the Florida Big Bend still have plenty of capacity and riverine flooding is not anticipated in these areas with this system. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 59 71 62 70 44 / 70 50 80 80 20 Panama City 60 71 62 66 46 / 80 50 80 70 20 Dothan 54 64 58 64 40 / 80 80 90 70 20 Albany 53 65 58 66 40 / 80 70 90 80 20 Valdosta 56 71 60 71 44 / 60 50 80 80 30 Cross City 61 77 61 74 48 / 20 30 60 70 30 Apalachicola 62 70 64 68 48 / 60 40 70 80 30 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...FLASH FLOOD WATCH through 6 AM CST Tuesday for Central Walton-Holmes-Inland Walton-Jackson-Washington. GA...FLASH FLOOD WATCH through 7 AM EST Tuesday for Baker-Ben Hill-Calhoun-Clay-Dougherty-Early-Irwin-Lee-Miller-Quitman- Randolph-Seminole-Terrell-Tift-Turner-Worth. AL...FLASH FLOOD WATCH through 6 AM CST Tuesday for Coffee-Dale- Geneva-Henry-Houston. GM...None. && $$ DISCUSSION...Lamers AVIATION...Evans MARINE...Evans FIRE WEATHER...Barry HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1146 AM CST MON FEB 11 2013 .SHORT TERM /TODAY/... MAIN FORECAST CONCERN TODAY IS WITH WINDS...AND LIGHT SNOW SHOWERS/FZDZ ACROSS NORTHERN IOWA. VERTICALLY STACKED LOW WILL CONTINUE TO PUSH EASTWARD THROUGH THE DAY AND PRESSURE GRADIENT BEGINS TO RELAX DURING THE AFTERNOON HOURS. NAM/GFS BUFR SOUNDINGS SUGGEST SOME LIGHT SNOW SHOWERS OR FLURRIES OVER NORTHERN IOWA THROUGH 18Z BUT RAP SHOWING LOSS OF ICE INTRODUCTION IN THE COLUMN PERIODICALLY DURING THE MORNING. SEVERAL CURRENT OBSERVATIONS ACROSS NORTHERN IOWA REPORTING DZ/UP SUGGESTING THIS IS ALREADY OCCURRING. FORCING REMAINS WEAK BUT LOOKS TO BE ENOUGH TO WARRANT THE MENTION OF PATCHY FZDZ ACROSS THE NORTHEAST THROUGH 18Z. WENT CLOSE TO GUIDANCE TODAY FOR MAX TEMPERATURES AS MODELS ARE IN GOOD AGREEMENT AND FELT NO REASON TO DEVIATE MUCH FROM THEM. THIS RESULTED IN TWEAKING TEMPS UP SLIGHTLY ACROSS THE SOUTH. NOT EXPECTING STRATUS TO CLEAR OUT ACROSS THE SOUTHWEST UNTIL AFTER 21Z WHEN THE PRESSURE GRADIENT BEGINS TO WEAKEN. KEPT OVERCAST OVER THE NORTH TO EAST THROUGH 00Z TUESDAY AS LOW LEVEL MOISTURE REMAINS PERSISTENT WITHIN THE CAA. .LONG TERM /TONIGHT THROUGH SUNDAY/... THE UPPER LOW PRESSURE WILL CONTINUE TO RACE OFF TO THE EAST TONIGHT AND BE NEAR MAIN BY 12Z TUESDAY MORNING. THIS WILL ALLOW MUCH DRIER AIR TO FILTER INTO THE STATE AS BROAD AREA OF HIGH PRESSURE SHIFTS EAST INTO THE MIDWEST. GENERAL TRENDS FOR TUESDAY AND WEDNESDAY ARE WARMER. THE DRY AIR WILL WARM NICELY ON TUESDAY UNDER SOUTHWEST FLOW. THE FLOW WILL BECOME MORE DOWN SLOPE ORIENTED TUESDAY NIGHT INTO WEDNESDAY AHEAD A VIGOROUS UPPER WAVE THAT WILL ARRIVE ALONG WITH AN ASSOCIATED COLD FRONT WEDNESDAY NIGHT. TEMPERATURES ON WEDNESDAY WILL BE IN THE MID TO UPPER 40S OVER THE CENTRAL AND SOUTH AND A FEW LOCATIONS MAY HIT 50 IF ENOUGH SUN IS AVAILABLE. THE UPPER WAVE WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. GUSTY NORTHWEST WINDS WILL KEEP COLD ADVECTION IN PLACE THROUGH THE DAY THURSDAY AND MAY HAVE SLOWLY FALLING TEMPERATURES DURING THE AFTERNOON. THE AIR MASS WITH THE SYSTEM WILL BE FAIRLY DRY WITH PWATS GENERALLY ONE QUARTER INCH OR LESS THEREFORE NO PRECIPITATION IS EXPECTED. ANOTHER UPPER WAVE WILL DROP INTO THE REGION THURSDAY NIGHT AND FRIDAY AND WILL HELP CARVE A LONG WAVE TROUGH OUT ACROSS THE NORTHERN PLAINS AND INTO THE EASTERN CONUS. THIS WILL BE ENHANCED AS HUDSON BAY UPPER LOW DROPS SOUTH INTO THE UPPER GREAT LAKES. 850 MB TEMPERATURES OVER THE STATE WILL BE AROUND -16C BY MID DAY FRIDAY. THE COLD AIR MASS WILL BE RELATIVELY DEEP AND WILL BE ABLE TO MIX WELL. THEREFORE DESPITE THE COLD AIR MASS...DEEP MIXING TO NEAR 850 MB WILL ALLOW TEMPERATURES RISE INTO THE UPPER TEENS TO UPPER 20S. SATURDAY AND SUNDAY WILL SEE GRADUAL MODERATION AS A WEAK RIDGE MOVES INTO THE STATE IN RESPONSE TO A STRONG SHORT WAVE DIVING INTO THE INTER MOUNTAIN WEST. && .AVIATION...11/18Z LOW PRESSURE OVER EASTERN LAKE SUPERIOR WILL MOVE INTO ONTARIO THIS AFTERNOON AS WEAK HIGH PRESSURE BUILDS INTO THE AREA. PRESSURE GRADIENT WILL GRADUALLY SLACKEN AS LOW RETREATS. AREAS OF MVFR CIGS WILL LIFT OUT OF THE AREA WITH THE LOW AS WINDS DIMINISH. SOME -SHSN AND BLSN IN THE KMCW AND KALO AREAS WILL ABATE AFTER 21Z. CLEARING TONIGHT WITH WINDS BECOMING LIGHT WEST...THEN SOUTHWEST LATE. && .DMX WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR BLACK HAWK-BREMER-BUTLER-CERRO GORDO- EMMET-FRANKLIN- GRUNDY-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-PALO ALTO- POCAHONTAS-TAMA-WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SHORT TERM...MS FEB 13 LONG TERM...DONAVON AVIATION...MS FEB 13
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1123 AM CST MON FEB 11 2013 .AVIATION... MVFR CONDITIONS WILL BE SEEN AT KCID/KDBQ/KMLI THROUGH SUNRISE BEFORE IMPROVING TO VFR. KDBQ MAY SEE SHSN THAT BRIEFLY LOWERS VSBYS. INTERNALLY...THE MODELS DO NOT SHOW ANY SIGNIFICANT SUBSIDENCE THAT WOULD HELP BREAK UP THE CLOUD COVER OVERNIGHT AND SATELLITE SHOWS EXTENSIVE CLOUDS BACK INTO THE DAKOTAS. WINDS WILL DECREASE THROUGH 00Z/12 AND SHOULD BE 10 KTS OR LESS AFTER SUNSET. HIGH PRESSURE BUILDING INTO THE MIDWEST AFT 12Z/12 SHOULD BREAK UP THE CLOUDS AND ALLOW VFR CONDITIONS WITH LIGHT WINDS. ..08.. && .PREV DISCUSSION... /ISSUED 1028 AM CST MON FEB 11 2013/ UPDATE... BASED ON SATELLITE TRENDS AND WHAT RECENT RAP TRENDS ARE SUGGESTING...CLOUDS SHOULD START BREAKING UP ACROSS THE SOUTHERN CWFA DURING THE AFTERNOON HOURS WHILE THEY REMAIN IN PLACE ACROSS THE NORTH. RAP TRENDS INDICATE LAPSE RATES WILL REMAIN QUITE STEEP THROUGH THE AFTERNOON BUT 925MB WINDS AND THE OVERALL GRADIENT DECREASES/RELAXES RESPECTIVELY. THE OVERALL WIND ADVISORY WILL REMAIN IN PLACE BASED ON THIS BUT WINDS SHOULD SLOWLY DECREASE FROM NOW THROUGH MID AFTERNOON. ..08.. PREV DISCUSSION... /ISSUED 238 AM CST MON FEB 11 2013/ SYNOPSIS... STRONG LOW PRESSURE WAS LOCATED OVER NORTHWEST WISCONSIN EARLY THIS MORNING. THE STRONG CYCLONIC FLOW AROUND THE LOW WAS SUPPORTING VERY WINDY CONDITIONS TO THE WEST AND SOUTHWEST. THE STRONGEST WINDS WERE OCCURRING NORTH OF I80 WHERE SUSTAINED SPEEDS WERE IN THE 30 TO 35 PLUS MPH RANGE WITH GUSTS OF 40 TO 50 MPH. SNOW SHOWERS WERE ALSO OCCURRING IN THE STRONG CYCLONIC FLOW. THE SHOWERS WERE REDUCING VISIBILITIES ALONG THE HIGHWAY 20 CORRIDOR TO MILE AT TIMES WHILE FURTHER SOUTH SCATTERED FLURRIES WERE OCCURRING. SHORT TERM...TODAY AND TONIGHT... VERY WINDY CONDITIONS WILL CONTINUE THROUGH MUCH OF THE DAY AS THE WISCONSIN LOW MOVES INTO SOUTHWEST ONTARIO BY LATE THIS AFTERNOON. MODELS ARE STILL SHOWING WEST WINDS AS HIGH A 50KTS THIS MORNING IN THE WELL MIXED SURFACE TO NEARLY 850MB LAYER WITH WINDS IN THIS LAYER DIMINISHING DURING DURING THE AFTERNOON. THIS SUPPORTS CONTINUING THE WIND ADVISORY THROUGH 21Z TODAY. EXPECT 40 TO 50 MPH GUSTS THIS MORNING THEN GRADUALLY DIMINISHING THIS AFTERNOON. THE STRONGEST WIND ARE EXPECTED TO OCCUR ALONG AND NORTH OF I80 THIS MORNING. WRAP AROUND SNOW SHOWERS WILL ALSO CONTINUE THROUGH THE DAY MAINLY NORTH OF HIGHWAY 30. SOME MINOR ACCUMULATIONS CAN/T BE RULED OUT...PROBABLY LESS THAN A HALF INCH. THE EDGE OF THE WRAP AROUND CLOUDS EXTENDS SOUTH INTO CENTRAL MO AND WEST THROUGH EASTERN NE EARLY THIS MORNING. THE BACK EDGE IN NE WAS CREEPING EAST AND CURRENT TIMING SUGGESTS IT COULD REACH SOUTHEAST IA THIS MORNING. HOWEVER...ANY CLEARING SHOULD BE BRIEF WITH CU/SC REDEVELOPING GIVEN THE STEEP LOW LEVEL LAPSE RATES. CLEARING SHOULD RESUME LATE THIS AFTERNOON AS THE CONVECTIVE CLOUDS DISSIPATE AND THE BETTER LOW LEVEL MOISTURE MOVES NORTHEAST. THIS EVENING THE SURFACE PRESSURE GRADIENT WILL CONTINUE TO RELAX AHEAD OF WEAK SURFACE RIDGE MOVING INTO CENTRAL IOWA. CLOUDS WILL ALSO MOVE NORTHEAST OF THE AREA DURING THE EVENING WITH CLEAR SKIES EXPECTED OVERNIGHT. WITH CLOUDS AND ONGOING COLD AIR ADVECTION WITH SHOULD SEE ABOUT A 10 DEGREE RECOVERY IN TEMPERATURES...PUTTING HIGHS MAINLY IN THE 30S. TONIGHT UPPER TEENS TO MID 20S LOOK REASONABLE WITH THE EXPECTED CLEARING AND DIMINISHING WIND. DLF LONG TERM...TUESDAY THROUGH SUNDAY... FORECAST FOCUS ON QUIET WEATHER EARLY TO MIDDLE PORTION OF THIS WEEK THEN TURNING COLDER LATE IN THE WEEK INTO NEXT WEEKEND. TUESDAY THROUGH THURSDAY...SPLIT FLOW ALLOWING FOR SOUTHERN STREAM STORM SYSTEM TO REMAIN UN-PHASED AS IT PUSHES QUICKLY INTO THE MID ATLANTIC STATES ON WEDNESDAY AND THEN OUT TO SEA. THIS SYSTEM COMBINED WITH A VERY INTENSE STORM IN THE GULF OF ALASKA PUMPS UP A FULL LATITUDE RIDGE FROM THE WEST COAST OF THE UNITED STATES INTO WESTERN CANADA. THIS BEGINS DEEPENING THE DOWNSTREAM TROUGH INTO THE NORTHERN PLAINS/UPPER MIDWEST BY THURSDAY. A STRONG COLD FRONT WILL BE PUSHING INTO THE DVN CWA ON THURSDAY BUT AHEAD OF THE FRONT TEMPERATURES WILL WARM UP INTO THE 40S ON WEDNESDAY. THURSDAY NIGHT AND FRIDAY...DEEPENING TROUGH IN THE EAST AND RIDGE IN THE ROCKIES WILL TAP ARCTIC AIR AND A RETURN TO COLDER WEATHER FOR THE MIDWEST. VERY COLD AIR ALOFT MAY ALLOW FOR AT LEAST SCATTERED SNOW SHOWERS. LOWS WILL BE IN THE TEENS NORTH AND 20S SOUTH WHILE HIGHS ON FRIDAY WILL BE ONLY IN THE 20S AT MOST LOCATIONS. THE LACK OF SNOW COVER ACROSS MUCH OF THE CWA WILL KEEP TEMPERATURES FROM REALLY TAKING A NOSE DIVE. FRIDAY NIGHT THROUGH SUNDAY...PROGRESSIVE PATTERN WILL PUSH THE EASTERN TROUGH FARTHER TO THE EAST BY SUNDAY WHILE RIDGE MOVES INTO THE PLAINS. TEMPERATURES SHOULD BEGIN TO MODERATE SOME BY SUNDAY. FRIDAY NIGHT AND SATURDAY LOOK TO BE QUITE COLD WITH LOWS DROPPING INTO THE SINGLE DIGITS NORTH AND TEENS SOUTH WHILE HIGHS ON SATURDAY WILL BE IN THE 20S. 850 MB TEMPERATURES DROP TO -18C IN PORTIONS OF THE CWA. ON SUNDAY...HIGHS SHOULD PUSH BACK INTO THE LOWER 30S IN OUR SOUTHERN COUNTIES BUT REMAINING IN THE 20S NORTH. HAASE && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BENTON-BUCHANAN- CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA- JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA- MUSCATINE-SCOTT-VAN BUREN-WASHINGTON. IL...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BUREAU-CARROLL- HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER- PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE. MO...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR CLARK-SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1028 AM CST MON FEB 11 2013 .UPDATE... BASED ON SATELLITE TRENDS AND WHAT RECENT RAP TRENDS ARE SUGGESTING...CLOUDS SHOULD START BREAKING UP ACROSS THE SOUTHERN CWFA DURING THE AFTERNOON HOURS WHILE THEY REMAIN IN PLACE ACROSS THE NORTH. RAP TRENDS INDICATE LAPSE RATES WILL REMAIN QUITE STEEP THROUGH THE AFTERNOON BUT 925MB WINDS AND THE OVERALL GRADIENT DECREASES/RELAXES RESPECTIVELY. THE OVERALL WIND ADVISORY WILL REMAIN IN PLACE BASED ON THIS BUT WINDS SHOULD SLOWLY DECREASE FROM NOW THROUGH MID AFTERNOON. ..08.. && .PREV DISCUSSION... /ISSUED 538 AM CST MON FEB 11 2013/ AVIATION... DEEP LOW PRESSURE WILL MOVE FROM WESTERN WI INTO THE NORTHERN GREAT LAKES BY THIS MORNING. WEST TO NORTHWEST WINDS BEHIND THE DEPARTING LOW WILL CONTINUE TO BE VERY STRONG...WITH SUSTAINED WINDS OF 20 TO 30 KTS...GUSTING TO 35 TO 40KTS AT TIMES INTO THIS AFTERNOON. WINDS WILL DECREASE TO 20KTS...GUST 30 KTS AROUND SUNSET AND THEN TO AROUND 10KTS BY MIDNIGHT. FLURRIES OR POSSIBLE LIGHT SNOW SHOWERS ARE EXPECTED AROUND DBQ THROUGH THIS MORNING. VISIBILITIES COULD DROP TO 1 TO 2 MILES IN SOME OF THE HEAVIER SNOW SHOWERS. CLOUDS BASES WERE IN THE 3000 FT TO 3500 FT RANGE OVER THE SOUTHWEST HALF OF THE FORECAST AREA WITH BASES WITH RANGING FROM 1500 TO 3000 FT BASES TO THE NORTHEAST EARLY THIS MORNING. THE VFR CIGS SHOULD CONTINUE TO SPREAD EAST THIS MORNING WITH VFR CIGS EXPECTED OVER MUCH OF THE AREA BY 18Z. SKIES WILL BE CLEARING LATE THIS AFTERNOON AND EARLY THIS EVENING. DLF PREV DISCUSSION... /ISSUED 238 AM CST MON FEB 11 2013/ SYNOPSIS... STRONG LOW PRESSURE WAS LOCATED OVER NORTHWEST WISCONSIN EARLY THIS MORNING. THE STRONG CYCLONIC FLOW AROUND THE LOW WAS SUPPORTING VERY WINDY CONDITIONS TO THE WEST AND SOUTHWEST. THE STRONGEST WINDS WERE OCCURRING NORTH OF I80 WHERE SUSTAINED SPEEDS WERE IN THE 30 TO 35 PLUS MPH RANGE WITH GUSTS OF 40 TO 50 MPH. SNOW SHOWERS WERE ALSO OCCURRING IN THE STRONG CYCLONIC FLOW. THE SHOWERS WERE REDUCING VISIBILITIES ALONG THE HIGHWAY 20 CORRIDOR TO MILE AT TIMES WHILE FURTHER SOUTH SCATTERED FLURRIES WERE OCCURRING. SHORT TERM...TODAY AND TONIGHT... VERY WINDY CONDITIONS WILL CONTINUE THROUGH MUCH OF THE DAY AS THE WISCONSIN LOW MOVES INTO SOUTHWEST ONTARIO BY LATE THIS AFTERNOON. MODELS ARE STILL SHOWING WEST WINDS AS HIGH A 50KTS THIS MORNING IN THE WELL MIXED SURFACE TO NEARLY 850MB LAYER WITH WINDS IN THIS LAYER DIMINISHING DURING DURING THE AFTERNOON. THIS SUPPORTS CONTINUING THE WIND ADVISORY THROUGH 21Z TODAY. EXPECT 40 TO 50 MPH GUSTS THIS MORNING THEN GRADUALLY DIMINISHING THIS AFTERNOON. THE STRONGEST WIND ARE EXPECTED TO OCCUR ALONG AND NORTH OF I80 THIS MORNING. WRAP AROUND SNOW SHOWERS WILL ALSO CONTINUE THROUGH THE DAY MAINLY NORTH OF HIGHWAY 30. SOME MINOR ACCUMULATIONS CAN/T BE RULED OUT...PROBABLY LESS THAN A HALF INCH. THE EDGE OF THE WRAP AROUND CLOUDS EXTENDS SOUTH INTO CENTRAL MO AND WEST THROUGH EASTERN NE EARLY THIS MORNING. THE BACK EDGE IN NE WAS CREEPING EAST AND CURRENT TIMING SUGGESTS IT COULD REACH SOUTHEAST IA THIS MORNING. HOWEVER...ANY CLEARING SHOULD BE BRIEF WITH CU/SC REDEVELOPING GIVEN THE STEEP LOW LEVEL LAPSE RATES. CLEARING SHOULD RESUME LATE THIS AFTERNOON AS THE CONVECTIVE CLOUDS DISSIPATE AND THE BETTER LOW LEVEL MOISTURE MOVES NORTHEAST. THIS EVENING THE SURFACE PRESSURE GRADIENT WILL CONTINUE TO RELAX AHEAD OF WEAK SURFACE RIDGE MOVING INTO CENTRAL IOWA. CLOUDS WILL ALSO MOVE NORTHEAST OF THE AREA DURING THE EVENING WITH CLEAR SKIES EXPECTED OVERNIGHT. WITH CLOUDS AND ONGOING COLD AIR ADVECTION WITH SHOULD SEE ABOUT A 10 DEGREE RECOVERY IN TEMPERATURES...PUTTING HIGHS MAINLY IN THE 30S. TONIGHT UPPER TEENS TO MID 20S LOOK REASONABLE WITH THE EXPECTED CLEARING AND DIMINISHING WIND. DLF LONG TERM...TUESDAY THROUGH SUNDAY... FORECAST FOCUS ON QUIET WEATHER EARLY TO MIDDLE PORTION OF THIS WEEK THEN TURNING COLDER LATE IN THE WEEK INTO NEXT WEEKEND. TUESDAY THROUGH THURSDAY...SPLIT FLOW ALLOWING FOR SOUTHERN STREAM STORM SYSTEM TO REMAIN UN-PHASED AS IT PUSHES QUICKLY INTO THE MID ATLANTIC STATES ON WEDNESDAY AND THEN OUT TO SEA. THIS SYSTEM COMBINED WITH A VERY INTENSE STORM IN THE GULF OF ALASKA PUMPS UP A FULL LATITUDE RIDGE FROM THE WEST COAST OF THE UNITED STATES INTO WESTERN CANADA. THIS BEGINS DEEPENING THE DOWNSTREAM TROUGH INTO THE NORTHERN PLAINS/UPPER MIDWEST BY THURSDAY. A STRONG COLD FRONT WILL BE PUSHING INTO THE DVN CWA ON THURSDAY BUT AHEAD OF THE FRONT TEMPERATURES WILL WARM UP INTO THE 40S ON WEDNESDAY. THURSDAY NIGHT AND FRIDAY...DEEPENING TROUGH IN THE EAST AND RIDGE IN THE ROCKIES WILL TAP ARCTIC AIR AND A RETURN TO COLDER WEATHER FOR THE MIDWEST. VERY COLD AIR ALOFT MAY ALLOW FOR AT LEAST SCATTERED SNOW SHOWERS. LOWS WILL BE IN THE TEENS NORTH AND 20S SOUTH WHILE HIGHS ON FRIDAY WILL BE ONLY IN THE 20S AT MOST LOCATIONS. THE LACK OF SNOW COVER ACROSS MUCH OF THE CWA WILL KEEP TEMPERATURES FROM REALLY TAKING A NOSE DIVE. FRIDAY NIGHT THROUGH SUNDAY...PROGRESSIVE PATTERN WILL PUSH THE EASTERN TROUGH FARTHER TO THE EAST BY SUNDAY WHILE RIDGE MOVES INTO THE PLAINS. TEMPERATURES SHOULD BEGIN TO MODERATE SOME BY SUNDAY. FRIDAY NIGHT AND SATURDAY LOOK TO BE QUITE COLD WITH LOWS DROPPING INTO THE SINGLE DIGITS NORTH AND TEENS SOUTH WHILE HIGHS ON SATURDAY WILL BE IN THE 20S. 850 MB TEMPERATURES DROP TO -18C IN PORTIONS OF THE CWA. ON SUNDAY...HIGHS SHOULD PUSH BACK INTO THE LOWER 30S IN OUR SOUTHERN COUNTIES BUT REMAINING IN THE 20S NORTH. HAASE && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BENTON-BUCHANAN- CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA- JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA- MUSCATINE-SCOTT-VAN BUREN-WASHINGTON. IL...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BUREAU-CARROLL- HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER- PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE. MO...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR CLARK-SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1230 PM EST MON FEB 11 2013 ...Updated Aviation Discussion... .Forecast Update... Issued at 1040 AM EST Mon Feb 11 2013 Ran a quick update this morning mainly to increase cloud cover across the southeast. A rather thick upper level deck looks as if it will stream across the Cumberland area through much of the day as another wave rides up along the departing frontal boundary. Also tweaked temperature and dewpoint grids to account for current trends. The jury is still out on the decision for an advisory late this morning into this afternoon. Louisville (SDF) gusted to 36 mph earlier this morning and Frankfort just recently gusted to 37 mph. However, both the 12Z NAM and the latest RAP soundings continue to advertise only about 35 knots at the top of the mixed layer late this morning, staying nearly steady or slowly weakening through the afternoon despite a deepening mixed layer. Will continue to monitor observations over the next few hours, but current thinking is that this event will best be handled with an SPS (although an isolated 40 mph gust is certainly possible). && .Short Term (Today - Tuesday)... Issued at 315 AM EST Mon Feb 11 2013 Light showers/drizzle redeveloped late last night and early this morning. This is currently in the process of exiting the forecast area, with dry air and reduced cloud cover working into the region. A vertically stacked low pressure system will meander eastward across the Great Lakes today. This will set up a tight pressure gradient at the surface, with even stronger winds aloft. Partly to mostly sunny skies and cold air advection aloft will aid mixing those winds to the surface. Sustained speeds between 15 and 25 mph are expected, with some gusts near 40 mph possible. Southern Indiana and north-central Kentucky will experience the strongest winds, with slightly weaker winds across south-central Kentucky. The peak period for the strongest winds will be from about mid morning through the afternoon. Wind speeds will decrease this evening, as the pressure gradient relaxes with surface high pressure and ridging aloft taking control. The high temperature forecast for today is tricky, with the ongoing cold air advection. We remained quite mild overnight, but cooler air is approaching from the west. Believe highs in the mid to upper 40s will be possible across southern Indiana, with lower 50s across north-central Kentucky and mid 50s across south-central and east-central Kentucky. Some of these highs, particularly in the north, may occur this morning and hold steady or only increase a degree or two with solar heating this afternoon. Lows tonight will drop into the upper 20s and lower 30s, with mostly clear skies. Typical cooler locations could dip into the mid 20s. Expect dry conditions, light westerly winds and temperatures ranging from the mid 40s to low 50s Tuesday. Clouds will increase through the day, ahead of our next system. .Long Term (Tuesday Night - Sunday)... Issued at 300 AM EST Mon Feb 11 2013 ...Light Wintry Precip Possible Wednesday Morning... The main concern in the long term period will be the possibility of light wintry precip Wed morning as an upper trough moves through the Ohio Valley. Still quite a bit of model spread on the track of the QPF field as it passes through our region, but have sided with a track similar to the 0Z GFS, GFS ensembles, and GEM. The 0Z ECMWF looks too suppressed compared to previous model runs and the 0Z NAM is much farther north than previous model runs. Certainly going with a consistency forecast here on the track of precipitation. One common theme among 0Z model guidance regardless of track is the slower timing of this weather system through the region. This theme combined with very dry low layers at onset of precip were evidence enough to delay precip arrival by around 4-6 hrs from the previous forecast. Looks like we should see some virga entering the region by around midnight Tues night, but precip shouldn`t start reaching the ground until closer to sunrise with the best coverage during the late morning/early afternoon hours Wed. Precipitation will be quick hitting and on its way out by late afternoon or early evening Wed. As far as precip type, boundary layer temps will be our determining factor as it looks like we`ll see ice crystal growth aloft with the main slug of moisture. With mild antecedent air and ground temps, think that most of the precip should fall as a cold rain. However, thermal profiles indicate that southern Indiana and north central KY may be cold enough Wed morning in a 2-5 hr window around sunrise for some snowflakes to fall. Also models do indicate some weak deformation with this system so if some heavier bands of precip set up in an environment with boundary layer temps close to freezing, we could see a change over to all snow briefly in heavier bands. Still with ground temps running in the lower 40s and low temps expected in the lower 30 to mid 30s across the area, think that any light snow accums would be short lived and shouldn`t cause much of a travel issue. Still stay abreast of the forecast for Wed morning`s commute as any changes in the thermal profile will affect ptype and potentially travel impacts. High temps on Wed are expected to top out in the lower 40s. Expect dry conditions for Thurs as zonal flow will dominate our region while a potent trough digs across the Plains states. This trough will push into the Midwest for the weekend creating a cool down. We`ll go from highs in the 40s to around 50 Thurs/Fri. to highs in the 30s Sat/Sun. Although no big weather makers look to impact the Ohio Valley with this upper trough, we will keep 20% POPs in the forecast as hard to time shortwaves that may produce light precip look possible Fri/Sat. && .Aviation (18Z TAF Issuance)... Issued at 1230 PM EST Mon Feb 11 2013 VFR conditions will prevail through the TAF period. The main issue over the next several hours will continue to be strong winds, as an area of low pressure pushes east through the Great Lakes. Expect westerly winds to continue at 15-20 knots, with gusts approaching 30 knots for the remainder of the afternoon across KLEX and KSDF. Winds will be slightly lower at KBWG, with 10-15 knots sustained and gusts just above 20 knots. Otherwise, winds will die down this evening, becoming variable by Tuesday as a surface ridge slides through the Ohio Valley. Some high clouds will begin to approach from the southwest toward the end of the TAF period in advance of the next system. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........KD Short Term.......MJP Long Term........AMS Aviation.........KD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
407 PM EST MON FEB 11 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 406 PM EST MON FEB 11 2013 PER WATER VAPOR IMAGERY AND RUC ANALYSIS...BROAD MID LEVEL TROUGH AND ASSOC CLOSED LOW ARE PROGRESSING STEADILY EAST OF THE UPPER GREAT LAKES. IN RESPONSE TO INCREASED RDGG FROM THE WEST...MODELS INDICATE INCREASING Q-VECT DIV/SUBSIDENCE SPREADING WEST TO EAST ACROSS FCST AREA INTO THIS EVENING. COMBINATION OF MQT RADAR...VIS SATELLITE AND AREA WEB CAMS SUGGEST ONLY LIGHT SNOW OR FLURRIES ACROSS THE CWA. THERE IS A BETTER BAND OF LES OVER WRN LAKE SUPERIOR AFFECTING NW WI THIS AFTERNOON WITH LIGHT TO MODERATE SNOW PER DLH RADAR. GIVEN THAT DEEPER MOISTURE WILL EXIT EAST TONIGHT WITH FLOW BCMG INCREASINGLY ANTICYCLONIC...SNOW NEAR LAKE SUPERIOR SHOULD STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE MARGINAL AROUND THE THRESHOLD FOR LES. AS A RESULT OF CONTINUED DIMINISHING TREND TO LES...EXPECT TO CANCEL REMAINING WINTER WX ADVISORIES OVER WRN COUNTIES ON THE AFTERNOON FCST ISSUANCE. EVEN IF BAND OVER NW WI DOES SWING INTO FAR WRN UPR MI...BELIEVE ANY INCREASE IN LES WILL BE SHORT-LIVED AND NOT BE WORTHY OF ADVISORY HEADLINE. LINGERING LIGHT LAKE EFFECT IS EXPECTED EAST TUE MORNING...BUT INCREASED DRYING/RDGG FROM WEST TO EAST...WARMING 850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE SURFACE RIDGE MOVING ACROSS THE REGION SHOULD QUICKLY DIMINISH OR END LAKE EFFECT SNOW DURING THE DAY TUESDAY. EXPECT CLOUDS TO GENERALLY DIMINISH AS WELL THROUGH THE DAY WITH INCREASED RDGG. GENERALLY FOLLOWED A BLEND OF CONSENSUS MODEL GUIDANCE FOR LOW TEMPS TONIGHT AND HIGH TEMPS ON TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 406 PM EST MON FEB 11 2013 EXPECT NW FLOW ALOFT THROUGH MUCH OF THE LONG TERM PERIOD...WITH SEVERAL OPEN WAVES DIVING TOWARD THE UPPER GREAT LAKES. LAKE EFFECT SNOW SHOWERS OVER THE KEWEENAW PENINSULA...AND NEAR AND EAST OF MUNISING NEAR LAKE SUPERIOR WILL BE COMMON. THE NEXT SYSTEM TO INFLUENCE OUR WEATHER WILL BE IN THE FORM OF A SFC TROUGH EXTENDING FROM THE PARENT LOW OVER HUDSON BAY. THE TROUGH WILL SWEEP W-E ACROSS UPPER MI TUESDAY NIGHT...BEFORE EXITING TO EASTERN ONTARIO LATE WEDNESDAY MORNING. 850MB TEMPS OF -7 TO -10C. YET ANOTHER QUICK CLIPPER SYSTEM SET UP OVER CENTRAL ALBERTA AND SASKATCHEWAN TUESDAY NIGHT WILL QUICKLY CROSS LAKE WINNIPEG WEDNESDAY MORNING...AND PUSH INTO WESTERN LAKE SUPERIOR WEDNESDAY EVENING...THEN ACROSS CENTRAL UPPER MI/LAKE SUPERIOR BY 12Z THURSDAY...AND EASTERN UPPER MI AROUND 18Z. WHILE THE NAM/GFS/ECMWF/SREF SHOW A SIMILAR TRACK TO THE SFC LOW...THE 11/00Z CANADIAN IS APPROX 300MI SW OF THE CONSENSUS. WILL LIMIT THE USE OF THE 11/00Z CANADIAN FORECAST FOR WEDNESDAY THROUGH THURSDAY. SNOW AMOUNTS WEDNESDAY NIGHT THROUGH THURSDAY COULD ACCUMULATE 3 TO 6 INCHES OF LES FROM IWD UP THROUGH THE KEWEENAW PENINSULA...WITH SNOW TO LIQUID RATIOS AROUND 17:1. LIGHTER AMOUNTS OF 2 TO 5 INCHES WILL BE POSSIBLE NORTH CENTRAL...AND 1 TO 3 INCHES ELSEWHERE. WILL ADD THE MENTION OF LIGHT TO MODERATE SNOW WITH LAKE ENHANCEMENT FOR WEDNESDAY NIGHT THROUGH THURSDAY...BEFORE THE DGZ FALLS CLOSER TO THE SFC AS COLDER AIR PUSHES IN...LIMITING SIGNIFICANT ACCUMULATIONS. A WEAKENING SFC TROUGH WILL AGAIN LINGER ACROSS CENTRAL AND EASTERN LAKE SUPERIOR THURSDAY NIGHT THROUGH SATURDAY AS STRONGER HIGH PRESSURE SINKS ACROSS THE CENTRAL CANADA AND THE PLAINS STATES...WITH A RIDGE EDGING INTO WESTERN UPPER MI/LAKE SUPERIOR. THE 11/12Z GFS WAS A BIT STRONGER WITH WHAT THE ECMWF HAS AS AN OPEN WAVE PUSHING IN FROM THE NNW SATURDAY...ACCENTUATING THE SFC LOW OVER EASTERN LAKE SUPERIOR. EITHER WAY...LAKE EFFECT SNOW SHOWERS WILL BE LINGERING OVER CENTRAL AND EASTERN UPPER MI NEAR LAKE SUPERIOR. EXPECT LES TO PICK UP SIGNIFICANTLY THURSDAY AFTERNOON AND EVENING AS COLDER AIR FILTERS IN BEHIND THE EXITING LOW ON FAVORABLE NNW WINDS. 850MB TEMPS WILL FALL TO AROUND -17C OVER THE W HALF BY THE END OF THE DAY THURSDAY...WITH FURTHER COOLING TO -19 TO -20C THROUGH THE START OF THE WEEKEND. -22 TO -24C LOOKS TO BE THE COOLEST POINT...SATURDAY AFTERNOON. WHILE THE 11/06Z GFS AND 11/00Z ECMWF ARE PRETTY CONSISTENT UNTIL SATURDAY...THEY BEGIN TO DIVERGE SATURDAY AFTERNOON...WITH THE GFS DEVELOPING A LOW OVER THE CENTRAL PLAINS BECOMING OUT OF PHASE WITH THE REST OF THE AVAILABLE MODELS. THE GOOD NEWS IS THAT THE 11/12Z GFS LOOKS TO HAVE FIXED THIS POTENTIAL PROBLEM...AND ANOTHER POSSIBLE STORM TOWARD THE EAST COAST FOR THE UPCOMING WEEKEND. EXPECT A COOL RIDGE OF HIGH PRESSURE TO EDGE ACROSS THE UPPER GREAT LAKES FOR THE WEEKEND...AS AN ELONGATED TROUGH GAINS STEAM FROM CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES ON SUNDAY. FOR MONDAY IT WILL BE A QUESTION AS TO IF THE SOUTHERN OR NORTHERN STREAM WINS OUT. AT THIS POINT THE 11/00Z ECMWF LOOKS TO BE STRONGER WITH THE SYSTEM AS A WHOLE...BUT WILL WAIT UNTIL THE TIME PERIOD BECOMES A BIT MORE CLEAR BEFORE LEANING TO ONE SOLUTION OVER ANOTHER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 125 PM EST MON FEB 11 2013 IFR CONDITIONS WITH LAKE ENHANCED -SN SHOULD PREVAIL AT KIWD/KCMX/KSAW THIS AFTERNOON UNDER GUSTY NNW WINDS ON BACKSIDE OF LOW PRES SYSTEM MOVING EAST OF LAKE SUPEPIOR. MID TO LATE AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS EXPECTED AS THE STORM SYSTEM CONTINUES TO MOVE EAST. MVFR CIGS MAY SCATTER OUT LATE TONIGHT AT KIWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT KSAW UNDER DOWNSLOPING W TO NW WINDS. LOOK FOR MVFR CIGS TO SCT OUT AT BOTH KCMX AND KSAW BY LATE TUE MORNING WITH INCREASED SUBSIDENCE AND RDGG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 406 PM EST MON FEB 11 2013 NW GALES OVER CENTRAL LAKE SUPERIOR AIDED BY PRES RISE MAX WILL DIMINISH BLO GALES BY LATE EVENING AS NW GRADIENT WEAKENS DUE TO LOW DEPARTING EAST AND RDG BUILDING IN FM WEST. HIGH PRES RDG AXIS MOVG EAST ACROSS THE LAKE WILL KEEP WINDS AOB 20 KTS OVER EAST HALF OF LAKE SUPERIOR. WEST HALF AND FAR NCNTRL LAKE SHOULD SEE AN INCREASE IN SW WINDS TUE AFTERNOON TO 25 KTS WITH TIGHTENING GRAD ON BACKSIDE OF RDG AXIS. A WEAK TROUGH STRETCHING FROM HUDSON BAY THROUGH THE UPPER GREAT LAKES TUESDAY NIGHT WILL BE REINFORCED BY ANOTHER LOW FROM THE NORTHWEST...THAT WILL PUSH ACROSS LAKE SUPERIOR/UPPER MI THURSDAY MORNING INTO THURSDAY AFTERNOON...BEFORE QUICKLY EXITING INTO SOUTERN ONTARIO AND QUEBEC THURSDAY AFTERNOON/EVENING. A FEW N GALE FORCE GUSTS TO 35KTS WILL BE POSSIBLE THURSDAY AFTERNOON ACROSS MAINLY CENTRAL LAKE SUPERIOR...WITH HEAVY FREEZING SPRAY OVER MUCH OF THE LAKE THURSDAY NIGHT. WHILE A WEAKENING TROUGH OF LOW PRESSURE REMAINS OVER EASTERN LAKE SUPERIOR...HIGH PRESSURE WILL SLOWLY BUILD IN FROM THE WEST THORUGH SATURDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>250-265-266. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...VOSS MARINE...VOSS/KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 PM EST MON FEB 11 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 525 AM EST MON FEB 11 2013 PER WATER VAPOR IMAGERY AND RUC ANALYSIS...MID LEVEL LOW IS CURRENTLY SPINNING EASTWARD OVER NRN WI ATTM. ASSOCIATED SFC LOW APPEARS TO BE NEARING THE AREA BTWN WATERSMEET AND IRON RIVER. WHILE MAIN BAND OF WAA/ISENTROPIC ASCENT PCPN HAS PUSHED WELL N AND E OF THE AREA...REGIONAL RADAR IMAGERY SHOWS AREAS OF MOSTLY LIGHT PCPN CIRCULATING AROUND THE MID LEVEL LOW. AHEAD OF THE LOW...LOW-LEVELS HAVE WARMED SUFFICIENTLY OVER ROUGHLY THE E HALF OF UPPER MI TO RESULT IN PTYPE BEING JUST RAIN EARLY THIS MORNING (SFC TEMPS HAVE EVEN RISEN TO THE MID/UPPER 30S). PCPN TRANSITIONS BACK TO SNOW OVER WRN UPPER MI AND NW WI. OVER THE NEXT SEVERAL HRS...COLUMN WILL COOL AS MID LEVEL LOW TRACKS EASTWARD. AS A RESULT...WHERE PCPN IS NOW RAIN...IT WILL CHANGE BACK TO ALL SNOW DURING THE MORNING. ATTENTION THEN TURNS TO POTENTIAL LAKE ENHANCEMENT TODAY. IT WON`T BE THE TYPICAL LAKE ENHANCED EVENT PRODUCING MDT/HVY SNOW THAT WOULD NORMALLY BE EXPECTED AT THIS TIME OF YEAR BECAUSE THE AIR MASS IS MILD ACROSS THE AREA RIGHT NOW (850MB TEMPS ARE -1 TO -5C OVER LAKE SUPERIOR). SO INITIALLY...EVEN AS WINDS INCREASE OUT OF THE N TO NW BEHIND SFC LOW...AIR MASS WILL BE TOO WARM FOR LAKE ENHANCEMENT THOUGH THERE WILL BE SOME TERRAIN ENHANCEMENT FROM THE UPSLOPING FLOW. OVER THE W...THERE WILL BE A WINDOW FOR LAKE ENHANCEMENT FROM LATE MORNING INTO THE AFTN AS 850MB TEMPS FALL BLO -7C. INTO NCNTRL UPPER MI...WINDOW LOOKS SHORTER LATE THIS AFTN/EVENING. THUS...PROBABLY SHOULDN`T SEE MUCH MORE THAN 2-4 INCHES OF SNOW OVER THE W TODAY. BEHIND THE SFC LOW...WINDS MORE QUICKLY BACK NW ACROSS NCNTRL UPPER MI WHICH WILL LIMIT LAKE ENHANCEMENT AND MORE QUICKLY DIMINISH TERRAIN ENHANCEMENT INTO MARQUETTE COUNTY. CONSIDERED DROPPING ADVY FOR MARQUETTE COUNTY... BUT WILL WAIT TO SEE HOW THINGS EVOLVE DURING THE MORNING OVER THE W TO GET AN IDEA OF HOW ENHANCEMENT WILL PLAY OUT OVER THE NCNTRL. IT`S POSSIBLE AN ADVY MAY BE NEEDED TO THE E OF MARQUETTE LATER THIS AFTN/EVENING...BUT EXPECTATION IS THAT SNOW ACCUMULATIONS WILL BE UNDER ADVY AMOUNTS. PERIOD OF GUSTY N/NW WINDS TO 30-35MPH ALONG LAKE SUPERIOR NW AND NCNTRL WILL LEAD TO SOME BLSN THIS AFTN/EVENING. AS FOR HEADLINES...CANCELLED ADVY FOR MENOMINEE/DELTA/ALGER EASTWARD AS TEMPS HAVE RISEN TO THE MID/UPPER 30S WITH ONLY RAIN FALLING. REMAINING ADVYS WERE NOT CHANGED. AS DEEPER MOISTURE EXITS TONIGHT...SNOW NEAR LAKE SUPERIOR SHOULD STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE MARGINAL AROUND THE THRESHOLD FOR LES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 424 AM EST MON FEB 11 2013 LINGERING LIGHT LAKE EFFECT IS EXPECTED FOR THE START OF THE LONG TERM PERIOD. BUT INCREASED DRYING FROM WEST TO EAST...WARMING 850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE SURFACE RIDGE MOVING ACROSS THE REGION ON TUESDAY WILL LEAD QUICKLY DIMINISHING LAKE EFFECT SNOW DURING THE DAY TUESDAY. CLOUDS WILL ALSO BE ON THE DECREASE THROUGH THE DAY AND GOING FORECAST HAS A DECENT TREND ON THAT IDEA. THE HIGH PRESSURE RIDGE QUICKLY SLIDES EAST ON TUESDAY AFTERNOON/EVENING AND AREA COMES UNDER THE INFLUENCE OF SEVERAL NORTHERN STREAM WAVES FOR THE REST OF THE WORK WEEK. THE FIRST WAVE...NEAR LAKE WINNIPEG AT 00Z WED...WILL DIVE SOUTHEAST ACROSS LAKE SUPERIOR ON WEDNESDAY. BEST DEEP MOISTURE LOOKS TO STAY OVER THE NORTHEAST HALF OF THE LAKE AND WITH GENERALLY WESTERLY FLOW ACROSS THE CWA...DON/T EXPECT MUCH FOR PRECIPITATION CHANCES ON WEDNESDAY EVEN THOUGH THE BROAD SURFACE TROUGH MOVES THROUGH. THE NEXT SHORTWAVE...TRACKING FARTHER TO THE SOUTHEAST...WILL DEPART ALBERTA ON WEDNESDAY AND MOVE INTO THE NORTHERN PLAINS ON WEDNESDAY EVENING AND THEN TRACK INTO THE WESTERN GREAT LAKES FOR THURSDAY. STILL SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND ENSEMBLE MEMBERS FROM THE GFS/GEM/ECMWF WITH THE STRENGTH OF THIS SHORTWAVE AND THE RESULTING STRENGTH/LOCATION OF THE ASSOCIATED SURFACE LOW. HPC PREFERS A BLEND OF THE 18Z GFES AND 12Z ECMWF ENS MEAN AND THAT SEEMS LIKE A DECENT COMPROMISE. THIS WOULD SWEEP THE SHORTWAVE THROUGH WISCONSIN ON THURSDAY AND HAVE A LOW 1000S MB LOW MOVING THROUGH NORTHERN WISCONSIN OR SOUTHERN UPPER MICHIGAN. AT THIS POINT...WOULD JUST EXPECT A DUSTING TO A COUPLE INCHES OF SNOW WITH THIS SYSTEM...UNLESS THE STRONGER GFS SOLUTION IS CORRECT WHICH WOULD PRODUCE ADVISORY SNOWFALL. ANOTHER SHORTWAVE DIVING SSE ON THE BACK SIDE OF THE THURSDAY SHORTWAVE WILL AMPLIFY THE UPPER TROUGH FURTHER AND LEAD TO IT MERGING WITH THE SOUTHERN STREAM FOR FRIDAY AND THE WEEKEND...WHILE AN UPPER RIDGE BUILDS OVER THE WRN CONUS. THIS WILL ALLOW COLDER AIR TO SPILL SOUTH ACROSS THE UPPER GREAT LAKES REGION AND PRODUCE A PERIOD OF BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. WITH THIS COLDER AIR...ALSO EXPECT THE AREA TO SEE LAKE EFFECT SNOW DUE TO 850MB TEMPS FALLING TOWARDS -21C BY SATURDAY. WITH A HIGH PRESSURE RIDGE EXPECTED TO BUILD INTO THE NORTHERN PLAINS DURING THIS TIME...WIND DIRECTIONS WILL DEPEND ON IF A LOW DEVELOPS AND MOVES UP THE ATLANTIC SEABOARD /ECMWF-YES AND GFS-MAYBE/. IF IT DOES OCCUR...WOULD EXPECT MORE N-NNW WIND LAKE EFFECT...WHILE NW LAKE EFFECT WOULD BE EXPECTED WITHOUT THE LOW. SINCE MODELS ARE MORE CONSISTENT ON LAKE EFFECT POTENTIAL FOR FRIDAY AND THE WEEKEND...WILL CONTINUE TO TREND POPS UP. A LITTLE TOO EARLY TO PIN DOWN TIMING/LOCATION FOR LIKELY POPS...BUT THERE APPEARS TO BE SEVERAL WEAK WAVES MOVING THROUGH THAT WILL INCREASE MOISTURE AND INTENSIFY THE LAKE EFFECT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 125 PM EST MON FEB 11 2013 IFR CONDITIONS WITH LAKE ENHANCED -SN SHOULD PREVAIL AT KIWD/KCMX/KSAW THIS AFTERNOON UNDER GUSTY NNW WINDS ON BACKSIDE OF LOW PRES SYSTEM MOVING EAST OF LAKE SUPEPIOR. MID TO LATE AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS EXPECTED AS THE STORM SYSTEM CONTINUES TO MOVE EAST. MVFR CIGS MAY SCATTER OUT LATE TONIGHT AT KIWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT KSAW UNDER DOWNSLOPING W TO NW WINDS. LOOK FOR MVFR CIGS TO SCT OUT AT BOTH KCMX AND KSAW BY LATE TUE MORNING WITH INCREASED SUBSIDENCE AND RDGG. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 525 AM EST MON FEB 11 2013 ON THE BACKSIDE OF LOW PRES MOVING ACROSS UPPER MI/ERN LAKE SUPERIOR TODAY...EXPECT A PERIOD OF N TO NW GALES TO DEVELOP FROM NW TO SE DURING THE DAY. APPROACHING HIGH PRES RIDGE WILL THEN CAUSE WINDS TO DIMINISH TO UNDER 25 KTS TONIGHT. WINDS WILL BECOME W-SW TUE/TUE NIGHT AS THE RIDGE SHIFTS TO THE E. THE W-SW FLOW WILL BE STRONGEST BTWN THE KEWEENAW AND ISLE ROYALE (POSSIBLY 20-30KT). LIGHTER WINDS UNDER 20KT SHOULD THEN PREVAIL LATER TUE NIGHT THRU WED NIGHT UNDER WEAKER PRES GRADIENT. LOW PRES WILL MOVE ACROSS THE WRN LAKES THU. BEHIND THE LOW...NORTHERLY WINDS WILL INCREASE INTO THE 15-30KT RANGE...STRONGEST OVER CNTRL/ERN LAKE SUPERIOR. FREEZING SPRAY WILL ALSO RETURN AS ARCTIC AIR FLOWS BACK INTO THE UPPER LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY FOR MIZ001>003-009. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004- 005-084. LAKE SUPERIOR... GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>250-265-266. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264. GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...VOSS MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1121 AM CST MON FEB 11 2013 .AVIATION...18Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE NEXT 24 HOURS. MID TO HIGH LEVEL CLOUDS WILL BE POSSIBLE AT THE TERMINAL DURING THE TAF PERIOD...BUT NOTHING BELOW 7000FT AGL CURRENTLY FORECAST. THE SURFACE WIND WILL REMAIN FROM THE NORTHWEST TODAY...SUSTAINED AT AROUND 17KTS AND GUSTING AROUND 23KTS. THIS WIND WILL DIMINISH THROUGH THE AFTERNOON HOURS AND EVENTUALLY BECOME LIGHT AND VARIABLE OVERNIGHT BEFORE BECOMING MORE ESTABLISHED FROM THE SOUTHWEST DURING THE DAY TUESDAY. VISIBILITY RESTRICTION IS NOT EXPECTED AT KGRI THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 433 AM CST MON FEB 11 2013/ SHORT TERM...THROUGH WEDNESDAY NIGHT. COMPARED TO THE PAST FEW DAYS...THESE NEXT 72 HOURS ARE LOOKING FAIRLY BENIGN WITH ESSENTIALLY ZERO RISK OF PRECIPITATION. HOWEVER...BOTH TUESDAY AND ESPECIALLY WEDNESDAY ARE TRENDING A BIT BREEZIER THAN PREVIOUSLY ADVERTISED...BUT ALSO A BIT WARMER AS WELL. 09Z OBJECTIVE SURFACE ANALYSIS PLACED THE CENTER OF THE DEPARTING...STRONG 991MB LOW OVER CENTRAL WI...WITH THE CENTRAL PLAINS CAUGHT WITHIN THE BACKSIDE OF THE TIGHT PRESSURE GRADIENT BETWEEN THIS LOW AND A ROUGHLY 1024MB HIGH OVER WY. A FAIRLY PRONOUNCED GRADIENT IN WIND SPEEDS IS EVIDENT ACROSS THE CWA AT THIS TIME...WITH NORTHWESTERLY SPEEDS AVERAGING NO MORE THAN 10-15 MPH IN SOUTHWEST AREAS...WHILE MOST CENTRAL/NORTHEAST AREAS CONTINUE TO REPORT SUSTAINED SPEEDS AT LEAST 15-20 MPH WITH GUSTS UP TO NEAR 30 MPH. FORTUNATELY THOUGH...SPEEDS HAVE FINALLY EASED WELL BELOW ADVISORY CRITERIA...WHICH TOOK A FEW HOURS LONGER EARLIER TONIGHT THAN ORIGINALLY THOUGHT. ANY LINGERING FLURRIES FROM EARLIER TONIGHT HAVE ALSO DEPARTED TO THE NORTHEAST...WITH IN FACT NEARLY FULLY CLEAR SKIES NOW OVER ALL BUT THE FAR EASTERN EDGES OF THE CWA WHERE SOME LOW STRATUS LINGERS. PRE-DAWN TEMPERATURES ARE FAIRLY UNIFORM ACROSS THE CWA...WITH MOST AREAS LIKELY HEADING FOR LOWS SOMEWHERE BETWEEN 21-27. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRMED AN ACTIVE PATTERN ACROSS THE CONUS...WITH THE NEARLY VERTICALLY STACKED CLOSED LOW DEPARTING OVER THE WI AREA...WHILE OFF TO OUR SOUTHWEST...A CURRENTLY OPEN 500MB SHORTWAVE TROUGH WAS CENTERED NEAR THE CA/NV/UT/AZ BORDERS...WITH ONLY THE SLIGHTEST HINT OF SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS IN BETWEEN THESE TWO PRIMARY LOWS. FORECAST-WISE TODAY...WHILE BY NO MEANS AS WINDY AS YESTERDAY...A HEALTHY NORTHWEST BREEZE OF 15-20 MPH WITH GUSTS 25+ MPH WILL PERSIST WELL INTO THE EARLY-MID AFTERNOON HOURS ACROSS ROUGHLY THE NORTHEAST 1/2 OF THE CWA THANKS TO EFFICIENT MIXING TO AROUND 850MB...BEFORE EASING MORE NOTICEABLY BETWEEN 3 PM AND SUNSET. ANY LINGERING/PRESUMABLY MINOR BLOWING SNOW ISSUES IN THE ORD AREA SHOULD CONTINUE TO ABATE WITH TIME. WIND SPEEDS ACROSS ROUGHLY THE SOUTHWEST 1/2 OF THE AREA WILL AVERAGE AT LEAST 5 MPH LIGHTER...AND ALSO START TO EASE UP SOONER ESPECIALLY THIS AFTERNOON AS A BROAD 1025MB RIDGE AXIS SETTLES INTO THE AREA. CLOUD-WISE...WHILE NEARLY THE ENTIRE AREA WILL START OUT WITH PLENTY OF SUNSHINE...THE AFTERNOON HOURS WILL BRING AT LEAST PARTLY CLOUDY SKIES TO MAINLY THE SOUTHWEST 1/2 OF THE CWA AS MID- HIGH CLOUDS SPREAD OVERHEAD DOWNSTREAM FROM THE SOUTHWEST CONUS LOW. THERE ARE SUGGESTIONS FROM THE LATEST HRRR RUNS THAT SOME SCATTERED LOW CLOUDS COULD ALSO INCREASE MAINLY THIS AFTERNOON IN SOME AREAS NORTH OF I-80...BUT WILL KEEP IT A MOSTLY SUNNY THEME HERE AT LEAST FOR NOW. AS FOR TEMPS...FOLLOWED THE 00Z NAM/05Z RAP SOLUTION RATHER CLOSELY...WHICH RESULTED IN A 1-3 DEGREE UPWARD NUDGE FROM PREVIOUS FORECAST...NOW RANGING FROM LOW 30S FAR NORTH...MID 30S CENTRAL...LOW 40S SOUTH MAINLY KS ZONES. ITS WORTH NOTING THAT THE 06Z NAM CAME IN COLDER FOR NORTHWEST COUNTIES...BUT THIS APPEARS TO BE A RESULT OF AN OVERDONE MODEL- INITIALIZED SNOW FIELD. THAT BEING SAID...CONFIDENCE IN TEMPS ISN/T QUITE AS HIGH ESPECIALLY FOR THE ORD AREA...WHERE A LIGHT COATING OF SNOW FROM YESTERDAY ALONG WITH A WIND DIRECTION BLOWING OFF OF THE DEEPER SNOW COVER OVER THE SANDHILLS COULD WORK TO HOLD THINGS DOWN A BIT. THIS EVENING/TONIGHT...CONFIDENCE REMAINS HIGH THAT THE ENTIRE CWA REMAINS PRECIPITATION-FREE...BUT THINGS DEFINITELY START TO TURN MORE INTERESTING A FEW COUNTIES TO OUR SOUTH...AS THE AFOREMENTIONED SOUTHWESTERN CONUS MID LEVEL SHORTWAVE TROUGH STARTS CLOSING OFF A BIT AS IT HEADS EAST INTO NM. FORCING DOWNSTREAM FROM THIS WAVE WILL SPREAD DECENT CHANCES FOR AT LEAST LIGHT ACCUMULATING SNOW INTO MAINLY THE SOUTHWEST 1/4 OF KS ESPECIALLY AFTER MIDNIGHT. WHILE A CONSENSUS OF VARIOUS MODELS SUCH AS THE NAM/ECMWF/4KM WRF-NMM KEEPS ANY OF THIS SNOW AT LEAST 80 MILES SOUTH OF THE FAR SOUTHERN CWA...THE NEW 06Z GFS HAS SUDDENLY TRENDED SLIGHTLY FARTHER NORTH...BRINGING AT LEAST A DUSTING OF SNOW WITHIN ROUGHLY 20 MILES OF FAR SOUTHERN ROOKS/OSBORNE COUNTIES. FOR NOW WILL DISCOUNT THIS RUN AS A NORTHERN OUTLIER AND STAND FIRM THAT THIS SYSTEM WILL NOT BE AN ISSUE FOR OUR CWA...AND BRING ONLY A PERIOD OF PARTLY/MOSTLY CLOUDY SKIES TO MAINLY OUR SOUTHERN COUNTIES. AT THE SURFACE TONIGHT...INITIALLY FAIRLY LIGHT/VARIABLE WINDS NEAR THE RIDGE AXIS WILL TAKE ON A SLIGHTLY STEADIER SOUTHWESTERLY COMPONENT LATE IN THE NIGHT IN RESPONSE TO A SUBTLE PASSING TROUGH AXIS. GIVEN THESE LIGHT WESTERLY BREEZES AND ALSO A FAIR AMOUNT OF PASSING CLOUD ESPECIALLY SOUTH...GENERALLY RAISED LOW TEMPS 2-4 DEGREES FROM PREVIOUS GRIDS...WITH ALL BUT FAR NORTHWESTERN AREAS HOLDING UP GENERALLY 17-22. TUESDAY DAYTIME...IN A CONTINUATION FROM LATE WED NIGHT ACCUMULATING SNOW WILL CONTINUE TO OUR SOUTH...TRACKING EASTWARD MAINLY ALONG/SOUTH OF THE KS/OK BORDER...AS THE PRIMARY 500MB SHORTWAVE ENDS UP OVER SOUTHERN/WESTERN OK BY DAYS END. AGAIN THOUGH...NO LOCAL IMPACT ANTICIPATED OTHER THAN MORE MID-HIGH CLOUD OVER KS ZONES VERSUS NEB ZONES. AT THE SURFACE...HIGH PRESSURE CENTERED TO THE WEST WILL DRIVE A WESTERLY DOWNSLOPE WIND COMPONENT ACROSS THE ENTIRE CWA...AND HAVE INCREASED SUSTAINED SPEEDS CLOSER TO 15 MPH WITH HIGHER GUSTS MAINLY FOR THE NORTHERN 1/2 OF THE CWA. ASSUMING THAT SUNSHINE IS FAIRLY PLENTIFUL IN MOST AREAS...AND GIVEN SLIGHT LOW LEVEL WARMING VERSUS MONDAY...SEE LITTLE REASON WHY THIS DOWNSLOPE WIND WON/T BRING A DECENT BOOST IN HIGH TEMPS...AND HAVE RAISED HIGHS GENERALLY 2-4 DEGREES FROM PREVIOUS FORECAST...ESPECIALLY IN EASTERN AREAS FARTHEST REMOVED FROM THE WESTERN/NORTH CENTRAL NEB SNOW FIELD. THIS NOW YIELDS HIGHS IN THE MID-UPPER 40S MOST AREAS...EXCEPT LOW 40S FAR NORTHWEST. TUESDAY NIGHT...THE SOUTHERN CONUS SHORTWAVE TROUGH TREKS EAST INTO THE AR/TN AREA...HELPING TRANSITION THE FLOW OVER THE CENTRAL PLAINS TO MORE PRONOUNCED NORTHWESTERLY...BUT WITH NO IMPACTFUL DISTURBANCES. ALTHOUGH A DECENT BATCH OF MID LEVEL CLOUDS COULD SAG SOUTHWARD ACROSS THE CWA...NOT EVEN EXPECTING FLURRIES AT THIS TIME. AT THE SURFACE...A LIGHT BUT STEADY 5-10 MPH WESTERN COMPONENT SHOULD AGAIN HELP KEEP TEMPS FROM FALLING TOO FAR...AND NUDGED UP PREVIOUS LOWS VERY SLIGHTLY...KEEPING MOST PLACES UP BETWEEN 21-24 DEGREES. WEDNESDAY...DRY NORTHWESTERLY FLOW ALOFT PERSISTS...AS THE LOCAL AREA REMAINS DOWNSTREAM FROM A LOW AMPLITUDE/CLIPPER-TYPE SHORTWAVE TROUGH SLIPPING OUT OF CANADA TO THE DAKOTAS/MN BORDER AREA BY DAYS END. UNDER GENERALLY PARTLY CLOUDY SKIES...A CONTINUED DOWNSLOPE WESTERLY WIND AND WARMER AIR EVIDENT ABOVE THE SURFACE AT 850MB SHOULD CONTINUE THE WARMING TREND FROM TUESDAY...AND HAVE MADE A VERY SLIGHT UPWARD NUDGE TO PREVIOUS HIGHS WITH MOST OF THE CWA INTO THE 50-53 RANGE...EXCEPT COOLER MID-UPPER 40S MAINLY IN OUR FAR NORTH/NORTHWEST FRINGES WHERE THE SNOW FIELD COULD STILL POSSIBLY EXERT SOME INFLUENCE. THE OVERALL BIGGEST CHANCE TO WEDNESDAY INVOLVED WIND SPEEDS...WHICH WERE UPPED AT LEAST 6-8 MPH FROM PREVIOUS GRIDS INTO BREEZY TERRITORY...AND NOW EXPECT SEVERAL HOURS OF SUSTAINED WEST-NORTHWEST SPEEDS 15-20 MPH WITH SOME HIGHER GUSTS. FORTUNATELY FOR POSSIBLE FIRE WEATHER CONCERNS...RELATIVE HUMIDITY VALUES ARE FORECAST TO FALL NO LOWER THAN THE UPPER-20S PERCENT...AND THIS IS ONLY IN A SMALL PART OF KS ZONES. WEDNESDAY NIGHT...THE AFOREMENTIONED NORTHERN PLAINS CLIPPER-SYSTEM DIVES DOWN MAINLY INTO IA/WI...WHILE AT THE SURFACE THE LEADING EDGES OF A MODEST COLD FRONT WILL ENTER THE LOCAL AREA. ALTHOUGH THE ORIENTATION OF THE UPPER JET ON THE WESTERN SIDE OF THIS DISTURBANCE ALONG WITH SOME MID LEVEL RH PROGS FROM MODELS SUCH AS THE 06Z NAM SUGGEST THAT A FEW FLURRIES MIGHT NOT BE OUT OF THE QUESTION FOR PARTS OF THE CWA...WILL KEEP ALL PRECIP MENTION OUT FOR NOW WITH POSSIBLY SLIGHTLY BETTER FLURRY CHANCES HOLDING OFF UNTIL THE THURS DAYTIME HOURS. MADE VERY LITTLE CHANGE TO LOW TEMPS WITH MID-UPPER 20S ALL AREAS. LONG TERM...THURSDAY THROUGH SUNDAY...AT THE ONSET OF THE EXTENDED PERIODS...100KT TO 120KT JET H3 JET STREAKS WILL NOSE SOUTH FM ALBERTA ACROSS THE EASTERN SLOPES OF THE NORTHERN ROCKIES CARVING A TROUGH ACROSS THE EASTERN TWO THIRDS OF THE CONUS. IN A NORTHWEST FLOW REGIME ACROSS THE CENTRAL PLAINS...COLD AIR WILL BACK IN FM THE NORTHEAST WITH THE MAIN THERMAL TROUGH ORIENTED FM ONTARIO THRU THE GREAT LAKES REGION. ENERGY TRANSLATING SOUTHEAST THRU FLOW AND A PUSH OF COLD AIR SOUTH THURSDAY COULD GENERATE SNOW FLURRIES IN OUR NORTHERN ZONES. FRIDAY WILL SEE A REINFORCING SHOT OF COLD AIR AS A STRONGER JET STREAK DIVES SOUTH ALONG THE FRONT RANGE OF THE ROCKIES AND ADDITIONAL SHORTWAVE ENERGY TRANSLATES ON THE WESTERN EDGE OF THE TROUGH WHICH ULTIMATELY FURTHER DEEPENS TO THE TROUGH ACROSS CENTRAL AND EASTERN CONUS. CURRENTLY HAVE FLURRIES IN THE FORECAST ON FRIDAY AND THIS IS STILL WARRANTED WITH FROPA/UPPER DYNAMICS. TEMPS WILL TREND COLDER THURSDAY...CLOSER TO SEASONAL NORMALS...AND WILL DROP FURTHER FRIDAY WITH STRONGER COLD FRONT. A COLD SURFACE HIGH PRESSURE SYSTEM WILL SETTLE ACROSS THE CENTRAL PLAINS BEHIND THE FRONT FRIDAY NIGHT...WHICH WILL RESULT IN TEMPS IN THE TEENS FOR LOWS. AFTER A COLD COUPLE OF DAYS FOR THE END OF THE WORKWEEK...THE WEATHER OVER THE WEEKEND TRENDS WARMER. THE SFC RIDGE AXIS SLIDES SOUTHEAST ON SATURDAY...ALLOWING FOR RETURN FLOW...AND ALOFT...THE UPPER TROUGH DEPARTS EASTWARD AND HEIGHTS BEGIN TO RISE ACROSS THE CENTRAL PLAINS. BY SUNDAY THE RIDGE WHICH WAS OVER THE ROCKIES SATURDAY REACHES THE INTERIOR CONUS..AND WARMER AIR SPREADS EASTWARD. SUNDAY IS LOOKING LIKE THE WARMEST OF THE EXTENDED PERIODS WITH HIGHS IN THE 40S FOR THE MOST PART AND 50S MAY NOT BE OUT OF THE QUESTION. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION...BRYANT SHORT TERM...PFANNKUCH LONG TERM...FAY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EST MON FEB 11 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST TO OUR SOUTH LATE TONIGHT. WEAK HIGH PRESSURE WILL MOVE IN LATE TONIGHT THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONT TUESDAY NIGHT AND WEDNESDAY... BRINGING UNSETTLED WEATHER. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 245 PM MONDAY... THROUGH TONIGHT: AS EXPECTED... THE WEDGE AIR MASS OVER THE TRIAD REGION HAS BEEN VERY TOUGH TO DISLODGE... AS EARLY AFTERNOON TEMPS REMAIN IN THE LOWER 50S WITH FOG AND VERY LOW STRATUS HOLDING ON... WHILE READINGS ARE MOSTLY IN THE 60S ELSEWHERE. SW WINDS JUST OFF THE SURFACE (AT 1-2 KFT AGL) ARE NOT QUITE AS STRONG AS THEY WERE THIS MORNING WITH THE DEPARTURE OF THE LOW LEVEL JET TO THE EAST BUT THEY CONTINUE TO PULL IN ENOUGH WARM AIR ALOFT SUCH THAT THE SURFACE-BASED STABLE LAYER IS REINFORCED VIA DIFFERENTIAL TEMP ADVECTION IN THE VERTICAL... DESPITE THE LACK OF A FEED OF COOL AIR AT THE SURFACE. AS SUCH... WE MAY SEE A MUTED FORM OF THIS WEDGE AIR MASS HANG IN OVER THE TRIAD THROUGH THIS EVENING... UNTIL THE COLD FRONT FINALLY SWEEPS THROUGH. LATEST CONVECTION-ALLOWING MODEL RUNS INCLUDING THE HRRR AND HIGH-RES WRF-NMM AND WRF-ARW SHOW WEAK LOW PRESSURE OVER NRN GA TRACKING ALONG THE FRONT AND IS ASSOCIATED WITH THE UPSTREAM PRECIP BAND NOW ACROSS NRN GA AND UPSTATE SC STREAMING TO THE ENE ACROSS THE FAR SRN/SE CWA... HOWEVER PREFRONTAL CONVECTION TO THE SSE OVER SRN GA MAY INTERRUPT THE POLEWARD MOISTURE TRANSPORT SUCH THAT WE`LL ONLY SEE LIGHT AMOUNTS AT MOST. WILL HOLD ONTO THE LOW CHANCE POPS OVER THE FAR SRN AND SE CWA THROUGH THIS EVENING... WITH DRY WEATHER OVERNIGHT. A SUBTLE MID LEVEL WAVE CONNECTED TO THE VORTEX CROSSING FAR SE ONTARIO AND SRN QUEBEC WILL CROSS THE MIDATLANTIC REGION LATER TONIGHT... FLATTENING THE MID LEVEL FLOW AND PROPELLING THE SURFACE FRONT TO OUR SOUTHEAST. THIS FLOW WILL REMAIN QUITE SWIFT TONIGHT... 80-90 KTS AT 500 MB... WITH PLENTY OF MOISTURE AT 310K-320K... SO EXPECT ABUNDANT MID LEVEL CLOUDS TO STREAM ACROSS THE AREA THROUGH THE NIGHT. LOWS 39-47. FOR TUESDAY/TUESDAY NIGHT: WILL SEE A BRIEF RESPITE IN THE ACTIVE PATTERN ON TUESDAY BEFORE THE RAIN RAMPS BACK UP TUESDAY EVENING. THE FRONT WILL HOLD TO OUR SOUTH WITH WEAK HIGH PRESSURE BUILDING OVER THE REGION. MID LEVEL FLOW REMAINS FAST (NEAR 80 KTS) OVER THE REGION BUT WILL BECOME GENTLY ANTICYCLONIC FOR A TIME... AS THE DEEP TROUGH LOCATED OVER THE FOUR CORNERS REGION STARTS TO KICK EASTWARD INTO THE SRN PLAINS. WE`LL LIKELY SEE PARTLY SUNNY SKIES GIVE WAY TO GREATER SUNSHINE TOWARD AFTERNOON... PARTICULARLY ACROSS THE NORTHERN CWA. LOW LEVEL THICKNESSES AS WELL AS THE LOW LEVEL THERMAL STRUCTURE SUPPORT HIGHS IN THE UPPER 50S TO LOWER 60S. THE MID LEVEL TROUGH SHIFTS THROUGH THE MID MISS VALLEY AS A POSITIVELY-TILTED WEAKENING WAVE... AND MODELS ALL AGREE ON A RAPID INCREASE IN DEEP MOIST ISENTROPIC UPGLIDE FROM 285K-305K OUT AHEAD OVER THE CAROLINAS. SIMILAR TO LAST NIGHT`S RAINFALL PATTERN... WITH THE FRONT LIKELY TO STILL HOLD SOUTH OF THE NC BORDER THROUGH TUESDAY NIGHT AND WITH INCREASING LAPSE RATES AND INSTABILITY OVER MS/AL/GA... WE SHOULD SEE THE GREATEST RISK OF HEAVY PRECIP CONFINED TO ALONG AND SOUTH OF THE BORDER. WITH A GOOD CHANCE OF A CONVECTIVE BAND WELL TO OUR SOUTH AND SW TUESDAY NIGHT... MOISTURE TRANSPORT MAY BE SUFFICIENTLY REDUCED TO GREATLY LIMIT AMOUNTS AND COVERAGE OVER NRN NC. NEVERTHELESS... GIVEN THE RESURGENCE OF 1+ INCH PRECIP WATER INTO THE SRN AND ERN CWA OVERNIGHT... CONFIDENCE IS HIGH ENOUGH FOR CATEGORICAL POPS IN THE SRN/SE CWA... TRENDING TO GOOD CHANCE NEAR THE VA BORDER. AMOUNTS ALONG/NORTH OF HIGHWAY 64 MAY BE LESS THAN A TENTH... WHILE AREAS NEAR THE SC BORDER COULD SEE A HALF INCH OR MORE. LOWS 40-46. -GIH && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 310 PM MONDAY... SHORTWAVE EJECTING OUT OF THE FOUR CORNERS REGION TUESDAY WILL RACE EAST ACROSS THE MS AND TN VALLEY REGIONS BY TUESDAY NIGHT NIGHT...SHEARING OUT AS IT CROSSES THE CAROLINAS ON WEDNESDAY. AS PRECIP SPREADS INTO THE AREA ON THE HEELS OF WEAK HIGH PRESSURE LATE TUESDAY NIGHT...ANOTHER CAD AIRMASS SHOULD DEVELOP OVER THE PIEDMONT. MODELS CONTINUE TO DIFFER REGARDING THE TRACK OF THE ASSOCIATED SURFACE LOW ALONG A STALLED OUT FRONTAL ZONE DRAPED ACROSS THE GULF/SOUTHEAST COAST. THE NAM CONTINUES TO BE THE NORTHERN OUTLIER WITH A LOW TRACK WEST OF THE MOUNTAINS. THE ECMWF APPEARS MORE REALISTIC WITH A TRACK ACROSS GA/SC TOWARD THE NC COAST. THE GFS SOMEWHERE IN BETWEEN TRACKING THE LOW TOWARD THE PIEDMONT...THEN JUMPING ACROSS THE EXPECTED CAD AIRMASS TO THE VA COAST. FAVORING A SOUTHERN TRACK OF THE LOW...THE BEST FOCUS OF DEEP MOISTURE AND LOW LEVEL CONVERGENCE WILL BE ACROSS SC TO SOUTHEAST NC...WHERE MODELS GIVE ONE HALF TO NEAR ONE INCH OF QPF IN TOTAL. AHEAD OF THE SHORTWAVE...MODELS SUGGEST A PLUME A STEEP MID LEVEL LAPSE RATES IN EXCESS OF -6.5 C/KM WITH A TRAJECTORY ACROSS CENTRAL NC. MODEST UPPER LEVEL FORCING FROM THE VORT MAX/LEFT EXIT REGION OF THE STJ...COMBINED WITH STRENGTHENING ISENTROPIC ACCENT IN THE LOW LEVELS...COULD LEAD TO A CHANCE OF THUNDER WEDNESDAY AFTERNOON. POPS WILL BE INCREASED TO ABOVE 80 PERCENT WITH THE HIGHEST VALUES SOUTH WEDNESDAY MORNING. HIGHS IN THE 40S TO POSSIBLY LOWER 50S IN THE SOUTHEAST. WESTERLY FLOW AND COLD/DRY ADVECTION IN THE WAKE OF THE DEPARTING SYSTEM SHOULD HELP TO SCOUR SOME OF THE LINGERING LOW CLOUDS WEDNESDAY NIGHT. LOWS IN THE LOW TO MID 30S. TEMPS SHOULD CLIMB BACK TO AROUND NORMAL ON THURSDAY WITH A LIGHT SOUTHWESTERLY WIND DEVELOPING AS HEIGHTS SLOWLY BEGIN TO FALL OVER THE CENTRAL US. HIGHS 52-57. LOWS THURSDAY NIGHT IN THE LOW TO MID 30S && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 310 PM MONDAY... MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN THROUGH THE WEEKEND...WITH RIDGING OVER THE WESTERN US AND A DEEP TROUGH DEVELOPING OVER THE EASTERN US. DETAILS REGARDING THE STRENGTH AND TIMING SHORTWAVES ROTATING INTO THE EAST COAST TROUGH REMAIN SOMEWHAT UNCERTAIN...BUT MODELS CURRENTLY PROJECT A WEAKER TROUGH AND COLD FRONTAL PASSAGE FRIDAY... AND A MORE SUBSTANTIAL TROUGH ARRIVING SATURDAY/SATURDAY NIGHT. BASED ON THE ECMWF AND A CONSENSUS OF GEFS SOLUTIONS...HPC CONTINUES TO FAVOR CYCLOGENESIS OFF THE MID-ATLANTIC COAST SATURDAY NIGHT...SUPPORTING LESS IMPACT OVER THE CAROLINAS. HOWEVER...EVEN WITH RUN-TO-RUN INCONSISTENCIES IN THE GFS/ECMWF...MODELS SUGGEST THE UPPER TROUGH MAY BE STRONG ENOUGH TO OVERCOME THE RELATIVELY DRY AIR OVER CENTRAL NC AND PRODUCE SOME LIGHT QPF. FORECAST LOW LEVEL THICKNESSES PLUMMET WELL BELOW 1300M WITH THE SECOND TROUGH ON SATURDAY....SO CONFIDENCE IS MODERATELY HIGH IN THERMAL PROFILES WILL BECOME FAVORABLE FOR SNOW SHOWERS. THE MAIN QUESTION WILL BE MOISTURE AVAILABILITY OR GENERATION FROM THE TROUGH....BUT THERE HAS BEEN ENOUGH CONSISTENCY IN THE MODELS TO INTRODUCE A SLIGHT CHANCE OF RAIN OR SNOW SHOWERS INTO THE FORECAST SATURDAY EVENING/NIGHT. TEMPS WILL BE TWO TO THREE CATEGORIES BELOW NORMAL SATURDAY AND ESPECIALLY SUNDAY. BEYOND SUNDAY...MODELS SHOW A RIDGE BUILDING EASTWARD ACROSS THE CENTRAL PORTION OF THE COUNTRY EARLY NEXT WEEK WITH A MODERATING TREND AND DRY CONDITIONS. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 120 PM TUESDAY... LIFR CONDITIONS WILL PERSIST FOR ANOTHER FEW HOURS AT INT/GSO... WHILE IFR/MVFR CIGS WITH VFR VSBYS WILL HOLD ELSEWHERE. A WEDGE BOUNDARY REMAINS TO THE SE OF INT/GSO... AND THE LIFR CIGS AND VSBYS AROUND 1 SM HAVE BUDGED LITTLE SO FAR TODAY. EXPECT CIGS TO SLOWLY LIFT EVERYWHERE BUT IMPROVE TO NO BETTER THAN MVFR THROUGH 23Z. CIGS ARE EXPECTED TO RISE TO VFR 01Z-04Z AS A COLD FRONT MOVES EAST THROUGH THE AREA... AND SWRLY SURFACE WINDS SHIFT AROUND TO WSW THEN FROM THE WEST AS A COLD FRONT MOVES THROUGH THE AREA... BEFORE SETTLING JUST TO OUR SOUTH OVERNIGHT. WINDS WILL APPROACH LLWS CRITERIA THROUGH THIS AFTERNOON AS SPEEDS AT 2 THOUSAND FT AGL WILL REMAIN FROM THE SW AT 35-40 KTS... BUT THE EXIT OF THE LOW LEVEL JET WILL CAUSE WINDS ALOFT TO DECREASE TO 25-35 KTS BY 00Z. THE INCREASING WINDS WITH HEIGHT MAY STILL CAUSE ISSUES WITH MECHANICAL TURBULENCE THROUGH THIS EVENING HOWEVER. VFR CIGS WILL HOLD FROM AROUND MIDNIGHT THROUGH TUESDAY MORNING AS WEAK HIGH PRESSURE BUILDS IN. LOOKING BEYOND 18Z TUESDAY... VFR CIGS WILL HOLD INTO TUESDAY EVENING BUT THEN DROP BACK DOWN TO IFR/LIFR OVERNIGHT AS A WAVE OF LOW PRESSURE TRACKS ALONG THE FRONT STALLED JUST TO OUR SOUTH. THESE POOR AVIATION CONDITIONS SHOULD HOLD THROUGH WEDNESDAY BEFORE IMPROVING TO VFR WEDNESDAY EVENING AS THE LOW EXITS. VFR CONDITIONS WILL THEN HOLD UNTIL SATURDAY... WHEN WE COULD SEE ANOTHER STORM SYSTEM BRINGING SUB-VFR CONDITIONS. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 PM EST MON FEB 11 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST TO OUR SOUTH LATE TONIGHT. WEAK HIGH PRESSURE WILL MOVE IN LATE TONIGHT THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONT TUESDAY NIGHT AND WEDNESDAY... BRINGING UNSETTLED WEATHER. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 245 PM MONDAY... THROUGH TONIGHT: AS EXPECTED... THE WEDGE AIR MASS OVER THE TRIAD REGION HAS BEEN VERY TOUGH TO DISLODGE... AS EARLY AFTERNOON TEMPS REMAIN IN THE LOWER 50S WITH FOG AND VERY LOW STRATUS HOLDING ON... WHILE READINGS ARE MOSTLY IN THE 60S ELSEWHERE. SW WINDS JUST OFF THE SURFACE (AT 1-2 KFT AGL) ARE NOT QUITE AS STRONG AS THEY WERE THIS MORNING WITH THE DEPARTURE OF THE LOW LEVEL JET TO THE EAST BUT THEY CONTINUE TO PULL IN ENOUGH WARM AIR ALOFT SUCH THAT THE SURFACE-BASED STABLE LAYER IS REINFORCED VIA DIFFERENTIAL TEMP ADVECTION IN THE VERTICAL... DESPITE THE LACK OF A FEED OF COOL AIR AT THE SURFACE. AS SUCH... WE MAY SEE A MUTED FORM OF THIS WEDGE AIR MASS HANG IN OVER THE TRIAD THROUGH THIS EVENING... UNTIL THE COLD FRONT FINALLY SWEEPS THROUGH. LATEST CONVECTION-ALLOWING MODEL RUNS INCLUDING THE HRRR AND HIGH-RES WRF-NMM AND WRF-ARW SHOW WEAK LOW PRESSURE OVER NRN GA TRACKING ALONG THE FRONT AND IS ASSOCIATED WITH THE UPSTREAM PRECIP BAND NOW ACROSS NRN GA AND UPSTATE SC STREAMING TO THE ENE ACROSS THE FAR SRN/SE CWA... HOWEVER PREFRONTAL CONVECTION TO THE SSE OVER SRN GA MAY INTERRUPT THE POLEWARD MOISTURE TRANSPORT SUCH THAT WE`LL ONLY SEE LIGHT AMOUNTS AT MOST. WILL HOLD ONTO THE LOW CHANCE POPS OVER THE FAR SRN AND SE CWA THROUGH THIS EVENING... WITH DRY WEATHER OVERNIGHT. A SUBTLE MID LEVEL WAVE CONNECTED TO THE VORTEX CROSSING FAR SE ONTARIO AND SRN QUEBEC WILL CROSS THE MIDATLANTIC REGION LATER TONIGHT... FLATTENING THE MID LEVEL FLOW AND PROPELLING THE SURFACE FRONT TO OUR SOUTHEAST. THIS FLOW WILL REMAIN QUITE SWIFT TONIGHT... 80-90 KTS AT 500 MB... WITH PLENTY OF MOISTURE AT 310K-320K... SO EXPECT ABUNDANT MID LEVEL CLOUDS TO STREAM ACROSS THE AREA THROUGH THE NIGHT. LOWS 39-47. FOR TUESDAY/TUESDAY NIGHT: WILL SEE A BRIEF RESPITE IN THE ACTIVE PATTERN ON TUESDAY BEFORE THE RAIN RAMPS BACK UP TUESDAY EVENING. THE FRONT WILL HOLD TO OUR SOUTH WITH WEAK HIGH PRESSURE BUILDING OVER THE REGION. MID LEVEL FLOW REMAINS FAST (NEAR 80 KTS) OVER THE REGION BUT WILL BECOME GENTLY ANTICYCLONIC FOR A TIME... AS THE DEEP TROUGH LOCATED OVER THE FOUR CORNERS REGION STARTS TO KICK EASTWARD INTO THE SRN PLAINS. WE`LL LIKELY SEE PARTLY SUNNY SKIES GIVE WAY TO GREATER SUNSHINE TOWARD AFTERNOON... PARTICULARLY ACROSS THE NORTHERN CWA. LOW LEVEL THICKNESSES AS WELL AS THE LOW LEVEL THERMAL STRUCTURE SUPPORT HIGHS IN THE UPPER 50S TO LOWER 60S. THE MID LEVEL TROUGH SHIFTS THROUGH THE MID MISS VALLEY AS A POSITIVELY-TILTED WEAKENING WAVE... AND MODELS ALL AGREE ON A RAPID INCREASE IN DEEP MOIST ISENTROPIC UPGLIDE FROM 285K-305K OUT AHEAD OVER THE CAROLINAS. SIMILAR TO LAST NIGHT`S RAINFALL PATTERN... WITH THE FRONT LIKELY TO STILL HOLD SOUTH OF THE NC BORDER THROUGH TUESDAY NIGHT AND WITH INCREASING LAPSE RATES AND INSTABILITY OVER MS/AL/GA... WE SHOULD SEE THE GREATEST RISK OF HEAVY PRECIP CONFINED TO ALONG AND SOUTH OF THE BORDER. WITH A GOOD CHANCE OF A CONVECTIVE BAND WELL TO OUR SOUTH AND SW TUESDAY NIGHT... MOISTURE TRANSPORT MAY BE SUFFICIENTLY REDUCED TO GREATLY LIMIT AMOUNTS AND COVERAGE OVER NRN NC. NEVERTHELESS... GIVEN THE RESURGENCE OF 1+ INCH PRECIP WATER INTO THE SRN AND ERN CWA OVERNIGHT... CONFIDENCE IS HIGH ENOUGH FOR CATEGORICAL POPS IN THE SRN/SE CWA... TRENDING TO GOOD CHANCE NEAR THE VA BORDER. AMOUNTS ALONG/NORTH OF HIGHWAY 64 MAY BE LESS THAN A TENTH... WHILE AREAS NEAR THE SC BORDER COULD SEE A HALF INCH OR MORE. LOWS 40-46. -GIH && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... AS OF 305 AM MONDAY... WEDNESDAY...EXPECT WIDESPREAD RAIN TO OVERSPREAD CENTRAL NC EARLY WED AND CONTINUE WELL INTO THE AFTERNOON. THE PRECIP AND OVERCAST SKIES WILL RESULT IN BELOW NORMAL TEMPS WITH MAX TEMPS HOLDING INT EH 40S ACROSS MOST OF THE PIEDMONT...AND THE LOWER 50S IN THE FAR SOUTH-SE. WEDNESDAY NIGHT...S/W CROSSES THE REGION IN THE EVENING THEN EXITS THE COAST. DRIER WNW FLOW BEHIND THIS SYSTEM AS WELL AS SUBSIDENCE WILL AID TO DISSIPATE CLOUD COVERAGE NW-SE DURING THE OVERNIGHT HOURS. RESIDUAL MOISTURE MAY RESULT IN SOME AREAS OF FOG BUT CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO INTRODUCE IN THE FORECAST AS MAY BE ENOUGH MIXING TO PREVENT FOG FROM DEVELOPING. MIN TEMPS MID-UPPER 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 305 AM MONDAY... THURSDAY INTO FRIDAY...RELATIVELY TRANQUIL WEATHER PATTERN ANTICIPATED AS BROAD TROUGH OVER THE EASTERN U.S. WILL CAUSE A WLY FLOW THROUGH THE COLUMN OVER CENTRAL NC. THIS USUALLY YIELDS DRY WEATHER WITH MILD TEMPS. LOW LEVEL THICKNESSES A SHADE ABOVE NORMAL THU AND NEAR NORMAL FRI BUT WLY FLOW USUALLY ADDS ADDITIONAL WARMING. AFTERNOON TEMPS IN THE 50S BOTH DAYS...APPROACHING 60 N THE FAR SOUTH FRI. BROAD UPPER TROUGH OVER EASTERN U.S. WILL UNDERGO AMPLIFICATION SATURDAY INTO SUNDAY AS PACIFIC ENERGY IS SHUNTED WELL NWD INTO ALASKA AND BRITISH COLUMBIA IN RESPONSE TO A STOUT UPPER LEVEL RIDGE OVER THE WESTERN U.S. THIS ENERGY DIVES ON SEWD INTO THE NORTH CENTRAL U.S. INITIATING THE AMPLIFICATION OF THE TROUGH. THIS WILL CAUSE A MODIFIED ARCTIC AIR MASS TO SPREAD SEWD ACROSS MUCH OF THE EASTERN U.S. THIS WEEKEND. THE LEADING EDGE OF THIS COLDER AIR WILL SPREAD ACROSS CENTRAL NC FRI NIGHT INTO SATURDAY. MODEL GUIDANCE CONTINUES TO EXHIBIT POSSIBLE SURFACE CYCLOGENESIS ASSOCIATED WITH THIS AMPLIFICATION OFF THE EASTERN SEABOARD IN VICINITY OF THE MID ATLANTIC COAST NWD TO NEW ENGLAND. CONSIDERING THE STRENGTH OF THE DISTURBANCES ALOFT...MAY BE ENOUGH TO TRIGGER SCATTERED SHOWERS ACROSS CENTRAL NC SATURDAY INTO SATURDAY EVENING. PARTIAL THICKNESSES AND FORECAST GFS BUFKIT SOUNDINGS SUGGEST THAT SNOW SHOWERS WOULD BE FAVORED OVER RAIN SHOWERS BUT MODELS MAY BE COOLING OFF THE COLUMN TOO QUICKLY. SINCE WE ARE TALKING ABOUT DAY 6...PREFER TO MAINTAIN A SLIGHT CHANCE POP FOR NOW AND KEEP PRECIP ALL LIQUID. HOWEVER DID BUMP UP CLOUDINESS A TAD AND LOWERED MAX TEMPS SATURDAY 2-3 DEGREES FROM THE PREVIOUS FORECAST. MAX TEMPS SATURDAY IN THE 40S TO NEAR 50 SOUTHEAST. IF PRECIP MORE EXTENSIVE THAN CURRENT THINKING...MAX TEMPS COULD BE TOO WARM BY AS MUCH AS 5-6 DEGREES. BULK OF COLDER AIR WILL SETTLE OVER THE REGION SUNDAY WITH MAX TEMPS 10-14 DEGREES BELOW NORMAL. MIN TEMPS SUN MORNING IN THE 20S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 120 PM TUESDAY... LIFR CONDITIONS WILL PERSIST FOR ANOTHER FEW HOURS AT INT/GSO... WHILE IFR/MVFR CIGS WITH VFR VSBYS WILL HOLD ELSEWHERE. A WEDGE BOUNDARY REMAINS TO THE SE OF INT/GSO... AND THE LIFR CIGS AND VSBYS AROUND 1 SM HAVE BUDGED LITTLE SO FAR TODAY. EXPECT CIGS TO SLOWLY LIFT EVERYWHERE BUT IMPROVE TO NO BETTER THAN MVFR THROUGH 23Z. CIGS ARE EXPECTED TO RISE TO VFR 01Z-04Z AS A COLD FRONT MOVES EAST THROUGH THE AREA... AND SWRLY SURFACE WINDS SHIFT AROUND TO WSW THEN FROM THE WEST AS A COLD FRONT MOVES THROUGH THE AREA... BEFORE SETTLING JUST TO OUR SOUTH OVERNIGHT. WINDS WILL APPROACH LLWS CRITERIA THROUGH THIS AFTERNOON AS SPEEDS AT 2 THOUSAND FT AGL WILL REMAIN FROM THE SW AT 35-40 KTS... BUT THE EXIT OF THE LOW LEVEL JET WILL CAUSE WINDS ALOFT TO DECREASE TO 25-35 KTS BY 00Z. THE INCREASING WINDS WITH HEIGHT MAY STILL CAUSE ISSUES WITH MECHANICAL TURBULENCE THROUGH THIS EVENING HOWEVER. VFR CIGS WILL HOLD FROM AROUND MIDNIGHT THROUGH TUESDAY MORNING AS WEAK HIGH PRESSURE BUILDS IN. LOOKING BEYOND 18Z TUESDAY... VFR CIGS WILL HOLD INTO TUESDAY EVENING BUT THEN DROP BACK DOWN TO IFR/LIFR OVERNIGHT AS A WAVE OF LOW PRESSURE TRACKS ALONG THE FRONT STALLED JUST TO OUR SOUTH. THESE POOR AVIATION CONDITIONS SHOULD HOLD THROUGH WEDNESDAY BEFORE IMPROVING TO VFR WEDNESDAY EVENING AS THE LOW EXITS. VFR CONDITIONS WILL THEN HOLD UNTIL SATURDAY... WHEN WE COULD SEE ANOTHER STORM SYSTEM BRINGING SUB-VFR CONDITIONS. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...WSS LONG TERM...WSS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 PM EST MON FEB 11 2013 .SYNOPSIS... A WARM FRONT WILL CONTINUE MOVING NORTHWARD THROUGH THE AREA TODAY. A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST TO OUR SOUTH... THEN WEAK HIGH PRESSURE WILL MOVE IN LATE TONIGHT THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONT AND AFFECT THE AREA ON WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY/... AS OF 950 AM MONDAY... REST OF TODAY: MAIN CONCERNS THIS MORNING ARE DEALING WITH THE DEPARTING RAIN... WIDELY VARYING TEMPS... AND WIND. WEDGE REGIME REMAINS WELL-ENTRENCHED OVER THE FAR NRN AND NW PIEDMONT... BISECTING THE TRIAD REGION WITH 9 AM TEMPS IN THE UPPER 50S IN ASHEBORO WHILE LOWER 40S HOLD AT LEXINGTON WITH FOG/STRATUS AND VERY LIGHT TO CALM AIR. THE 12Z GSO SOUNDING SHOWS A FORMIDABLE STABLE LAYER (+4C DIFFERENTIAL FROM SURFACE TO WARM NOSE ALOFT) WITH DEEP SATURATION... AND EVEN OUTSIDE OF THIS DEFINED WEDGE... DESPITE THE MILDER TEMPS IN THE 50S... THE LOW LEVELS (UNDER 900 MB) REMAIN NEUTRAL TO SLIGHTLY STABLE AS NOTED BY RECENT AMDAR AIRCRAFT SOUNDINGS NEAR RDU. WINDS HERE ARE BEGINNING TO PICK UP OUT OF THE SOUTH AND SW THOUGH... INDICATING THAT IMPROVED LOW LEVEL MIXING IS IMMINENT. THE WIDESPREAD LIGHT RAIN IS ON ITS WAY OUT A BIT MORE QUICKLY THAN EARLIER ANTICIPATED... HOWEVER WITH BLENDED TPW IMAGERY SHOWING PRECIP WATER VALUES OVER 200 PERCENT OF NORMAL ACROSS THE ENTIRE REGION... THE RISK OF PATCHY SHOWERS WILL REMAIN FOR ANOTHER SEVERAL HOURS AS THE MOIST COLUMN WILL STAY VULNERABLE TO EVEN SUBTLE FORCING FOR ASCENT. WILL HOLD ONTO SMALL POPS MAINLY S/E OF THE TRIAD INTO THE AFTERNOON. LOW CLOUDS SHOULD HOLD IN EVERYWHERE UNTIL MID AFTERNOON WITH THE CONTINUED LOW-MID LEVEL FLOW FROM THE SW ELIMINATING THE POTENTIAL FOR SIGNIFICANT DOWNSLOPE DRYING UNTIL LATE... WHEN THE MID LEVEL PERTURBATION NOW OVER NW NC MOVES OFF THE COAST. TEMPS ARE ALWAYS TOUGH TO GAUGE IN THESE WEDGE SITUATIONS ESPECIALLY WHEN THERE IS NO LONGER A FEED OF LOW LEVEL DRY AIR TO MAINTAIN THE STABLE POOL. ALL FINE-RESULTION GUIDANCE INCLUDING THE LOCAL WRF AND HRRR FAVORS A MIXING-OUT OF THE REMAINING WEDGE OVER OUR NW CWA BY EARLY AFTERNOON... ALTHOUGH THE ABUNDANT THICK CLOUDS FOR MUCH OF THE DAY WILL CUT DOWN ON WARMING ALL ACROSS THE AREA. NEVERTHELESS.... ANOMALOUSLY WARM THICKNESSES WILL RISE FURTHER THIS AFTERNOON... AND STILL EXPECT HIGHS IN THE MID 60S TO NEAR 70 OVER MUCH OF THE CWA EXCEPT FOR NEAR 60 IN THE NW CORNER. SINCE WE WON`T FULLY MIX UP BEYOND 900 MB UNTIL LATE IN THE DAY... WHEN THE 50-60 KT LOW LEVEL JET WILL HAVE EXITED... OUR WIND GUSTS WILL REMAIN WELL BELOW ADVISORY THRESHOLD... YET WE SHOULD STILL SEE GUSTS BECOME MORE FREQUENT AND HIGHER THIS AFTERNOON ESPECIALLY OUTSIDE THE DECAYING WEDGE REGION. GUSTS SHOULD EXCEED 20-25 KTS PERIODICALLY. -GIH TONIGHT AND TUESDAY: SURFACE COLD FRONT IS EXPECTED TO QUICKLY MOVE ACROSS THE AREA LATE TODAY INTO THIS EVENING WITH THE LOW LEVEL AIRMASS COMPLETELY SCOURING OUT AS IT MOVES THROUGH. HOWEVER... WE WILL KEEP A LEAST SOME MID AND HIGH LEVEL CLOUD COVER... ESPECIALLY ACROSS THE SOUTH.... WHILE THE SURFACE FRONT STALLS TO THE SOUTH OF THE AREA. EXPECT LOW TEMPS TONIGHT TO RANGE FROM AROUND 40 NW TO UPPER 40S SE... WITH A WEST TO NORTHWESTERLY BREEZE AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. TUESDAY WILL START OFF WITH QUITE WEATHER. HOWEVER... A SOUTHERN STREAM DISTURBANCE WILL BEGIN APPROACHING THE REGION FROM THE SOUTHWEST ON TUESDAY... SPREADING MORE CLOUDS INTO THE AREA AND PERHAPS SOME LIGHT RAIN ACROSS THE FAR SOUTHWEST LATE IN THE DAY. HIGH TEMPS ARE AGAIN EXPECTED TO BE ABOVE NORMAL AS THE SYSTEM APPROACHES FROM THE SOUTH AND SURFACE WINDS QUICKLY SWING BACK AROUND TO WSW TO SOUTHWESTERLY IN ADVANCE OF THE DISTURBANCE. THUS... WILL GO WITH HIGHS IN THE LOWER TO MID 60S. -BSD && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 305 AM MONDAY... TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... NEXT LOW PRESSURE SYSTEM IN THE ACTIVE SOUTHERN STREAM PROJECTED TO TRAVERSE THE SOUTHERN PLAINS INTO THE LOWER MS VALLEY LATE TUE-TUE NIGHT. THIS WEATHER SYSTEM WILL INDUCE THE FORMATION OF A SURFACE LOW ON THE STALLED FRONT OVER THE NORTHERN GULF COAST BY LATE TUESDAY. THE 00Z GFS TAKES THIS SURFACE WAVE NEWD UP THE SOUTHERN APPALACHIANS THEN EWD ACROSS THE NC-VA PIEDMONT. 00Z ECMWF FITS INTO THE CLASSICAL MODEL WITH THE WAVE PROGRESSING ENE ALONG A STALLED SURFACE BOUNDARY ACROSS SOUTHERN AL-SOUTHERN GA THEN OFF THE CAROLINA COASTS WHERE IT INTENSIFIES IN THE FAVORABLE BAROCLINIC ZONE CAUSED BY THE GULF STREAM. INCREASING SLY FLOW AHEAD OF THE SURFACE LOW WILL CAUSE AN OVERRUNNING PRECIP EVENT ACROSS CENTRAL NC LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING. THE INCREASING MOISTURE WILL ALSO BE LIFTED BY NOT ONLY THE MID-UPPER LEVEL S/W BUT ALSO FROM A FAVORABLE JET CONFIGURATION WITH CENTRAL NC IN THE NOSE OF 140+ KT JET. THUS...EXPECT WIDESPREAD RAIN TO OVERSPREAD CENTRAL NC EARLY WED AND CONTINUE WELL INTO THE AFTERNOON. THE PRECIP AND OVERCAST SKIES WILL RESULT IN BELOW NORMAL TEMPS WITH MAX TEMPS HOLDING INT EH 40S ACROSS MOST OF THE PIEDMONT...AND THE LOWER 50S IN THE FAR SOUTH-SE. WEDNESDAY NIGHT...S/W CROSSES THE REGION IN THE EVENING THEN EXITS THE COAST. DRIER WNW FLOW BEHIND THIS SYSTEM AS WELL AS SUBSIDENCE WILL AID TO DISSIPATE CLOUD COVERAGE NW-SE DURING THE OVERNIGHT HOURS. RESIDUAL MOISTURE MAY RESULT IN SOME AREAS OF FOG BUT CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO INTRODUCE IN THE FORECAST AS MAY BE ENOUGH MIXING TO PREVENT FOG FROM DEVELOPING. MIN TEMPS MID-UPPER 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 305 AM MONDAY... THURSDAY INTO FRIDAY...RELATIVELY TRANQUIL WEATHER PATTERN ANTICIPATED AS BROAD TROUGH OVER THE EASTERN U.S. WILL CAUSE A WLY FLOW THROUGH THE COLUMN OVER CENTRAL NC. THIS USUALLY YIELDS DRY WEATHER WITH MILD TEMPS. LOW LEVEL THICKNESSES A SHADE ABOVE NORMAL THU AND NEAR NORMAL FRI BUT WLY FLOW USUALLY ADDS ADDITIONAL WARMING. AFTERNOON TEMPS IN THE 50S BOTH DAYS...APPROACHING 60 N THE FAR SOUTH FRI. BROAD UPPER TROUGH OVER EASTERN U.S. WILL UNDERGO AMPLIFICATION SATURDAY INTO SUNDAY AS PACIFIC ENERGY IS SHUNTED WELL NWD INTO ALASKA AND BRITISH COLUMBIA IN RESPONSE TO A STOUT UPPER LEVEL RIDGE OVER THE WESTERN U.S. THIS ENERGY DIVES ON SEWD INTO THE NORTH CENTRAL U.S. INITIATING THE AMPLIFICATION OF THE TROUGH. THIS WILL CAUSE A MODIFIED ARCTIC AIR MASS TO SPREAD SEWD ACROSS MUCH OF THE EASTERN U.S. THIS WEEKEND. THE LEADING EDGE OF THIS COLDER AIR WILL SPREAD ACROSS CENTRAL NC FRI NIGHT INTO SATURDAY. MODEL GUIDANCE CONTINUES TO EXHIBIT POSSIBLE SURFACE CYCLOGENESIS ASSOCIATED WITH THIS AMPLIFICATION OFF THE EASTERN SEABOARD IN VICINITY OF THE MID ATLANTIC COAST NWD TO NEW ENGLAND. CONSIDERING THE STRENGTH OF THE DISTURBANCES ALOFT...MAY BE ENOUGH TO TRIGGER SCATTERED SHOWERS ACROSS CENTRAL NC SATURDAY INTO SATURDAY EVENING. PARTIAL THICKNESSES AND FORECAST GFS BUFKIT SOUNDINGS SUGGEST THAT SNOW SHOWERS WOULD BE FAVORED OVER RAIN SHOWERS BUT MODELS MAY BE COOLING OFF THE COLUMN TOO QUICKLY. SINCE WE ARE TALKING ABOUT DAY 6...PREFER TO MAINTAIN A SLIGHT CHANCE POP FOR NOW AND KEEP PRECIP ALL LIQUID. HOWEVER DID BUMP UP CLOUDINESS A TAD AND LOWERED MAX TEMPS SATURDAY 2-3 DEGREES FROM THE PREVIOUS FORECAST. MAX TEMPS SATURDAY IN THE 40S TO NEAR 50 SOUTHEAST. IF PRECIP MORE EXTENSIVE THAN CURRENT THINKING...MAX TEMPS COULD BE TOO WARM BY AS MUCH AS 5-6 DEGREES. BULK OF COLDER AIR WILL SETTLE OVER THE REGION SUNDAY WITH MAX TEMPS 10-14 DEGREES BELOW NORMAL. MIN TEMPS SUN MORNING IN THE 20S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 120 PM TUESDAY... LIFR CONDITIONS WILL PERSIST FOR ANOTHER FEW HOURS AT INT/GSO... WHILE IFR/MVFR CIGS WITH VFR VSBYS WILL HOLD ELSEWHERE. A WEDGE BOUNDARY REMAINS TO THE SE OF INT/GSO... AND THE LIFR CIGS AND VSBYS AROUND 1 SM HAVE BUDGED LITTLE SO FAR TODAY. EXPECT CIGS TO SLOWLY LIFT EVERYWHERE BUT IMPROVE TO NO BETTER THAN MVFR THROUGH 23Z. CIGS ARE EXPECTED TO RISE TO VFR 01Z-04Z AS A COLD FRONT MOVES EAST THROUGH THE AREA... AND SWRLY SURFACE WINDS SHIFT AROUND TO WSW THEN FROM THE WEST AS A COLD FRONT MOVES THROUGH THE AREA... BEFORE SETTLING JUST TO OUR SOUTH OVERNIGHT. WINDS WILL APPROACH LLWS CRITERIA THROUGH THIS AFTERNOON AS SPEEDS AT 2 THOUSAND FT AGL WILL REMAIN FROM THE SW AT 35-40 KTS... BUT THE EXIT OF THE LOW LEVEL JET WILL CAUSE WINDS ALOFT TO DECREASE TO 25-35 KTS BY 00Z. THE INCREASING WINDS WITH HEIGHT MAY STILL CAUSE ISSUES WITH MECHANICAL TURBULENCE THROUGH THIS EVENING HOWEVER. VFR CIGS WILL HOLD FROM AROUND MIDNIGHT THROUGH TUESDAY MORNING AS WEAK HIGH PRESSURE BUILDS IN. LOOKING BEYOND 18Z TUESDAY... VFR CIGS WILL HOLD INTO TUESDAY EVENING BUT THEN DROP BACK DOWN TO IFR/LIFR OVERNIGHT AS A WAVE OF LOW PRESSURE TRACKS ALONG THE FRONT STALLED JUST TO OUR SOUTH. THESE POOR AVIATION CONDITIONS SHOULD HOLD THROUGH WEDNESDAY BEFORE IMPROVING TO VFR WEDNESDAY EVENING AS THE LOW EXITS. VFR CONDITIONS WILL THEN HOLD UNTIL SATURDAY... WHEN WE COULD SEE ANOTHER STORM SYSTEM BRINGING SUB-VFR CONDITIONS. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BSD SHORT TERM...WSS LONG TERM...WSS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
457 PM EST MON FEB 11 2013 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS EVENING...FOLLOWED BY WINDY AND COOLER CONDITIONS TONIGHT INTO TUESDAY. LOW PRESSURE OVER THE GULF COAST IS EXPECTED TO TRACK NORTHEAST AND OFF THE DELMARVA PENINSULA LATE WEDNESDAY NIGHT. THIS STORM SYSTEM COULD BRING A PERIOD OF SNOW TO SOUTHEASTERN AREAS LATE WEDNESDAY AND WEDNESDAY NIGHT. MAINLY DRY CONDITIONS WITH A BRISK WESTERLY WIND...AND NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES WILL FOLLOW FOR THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... EARLY EVENING VIS IMAGERY SHOWING LOW CLOUDS REMAIN EAST OF THE SUSQ VALLEY. LATEST RAP MDL DATA SUGGESTS LITTLE MOVEMENT TO WARM FRONT BEFORE ARRIVAL OF COLD/OCCLUDED FRONT THIS EVENING. THE OVERNIGHT WILL FEATURE A PRETTY TYPICAL POST COLD FRONTAL FLOW PATTERN WITH NORTHWEST FLOW...STRATOCU CEILINGS AND SCATTERED SNOW SHOWERS OVER THE NORTHWEST AND WEST. EXPECT AN INCH OR TWO OF NEW SNOW OVER THE USUAL AREAS DOWNWIND FROM THE LAKE AND OVER UPSLOPE LOCATIONS IN THE LAURELS...BUT LITTLE MORE THAN FLURRIES ELSEWHERE. THE MAIN THING WILL BE THE INCREASE IN WIND AS THE COLDER AIR FILTERS IN. THE BEST PRESSURE RISES MOVE NORTH OF THE STATE...BUT COLD ADVECTION AND SUBSIDENCE MAY BE ENOUGH TO BRING ABOUT SOME ISOLATED WIND GUSTS IN THE ADVISORY RANGE LATER TONIGHT INTO TUESDAY MORNING. WILL KEEP THE CURRENT ADVISORY WIND ADVISORY CONFIGURATION. OVERNIGHT LOWS WILL AVERAGE WELL ABOVE SEASONAL NORMALS IN THE 20S TO LOWER 30S. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... WINDS WILL GRADUALLY DECREASE THROUGHOUT THE DAY TUESDAY WITH MOSTLY CLOUDY TO CLOUDY SKIES ACROSS THE CENTRAL AND NRN ZONES...AND SOME BREAKS OF SUNSHINE OVER THE SOUTHERN TIER OF THE STATE . SCATTERED MORNING SNOW SHOWERS ACROSS THE NW MTNS WILL DIMINISH TO JUST SOME AFTERNOON FLURRIES...AS THE SURFACE HIGH BUILDS ACROSS JUST TO OUR SOUTH BRINGING A LOWER INVERSION HEIGHT AND ALLOWING CLOUDS TO BECOME SHALLOWER IN THE AFTERNOON. HIGHS TUESDAY IN THE 30S AND 40S WILL RANGE FROM NEAR NORMAL OVER THE NORTH TO A BIT ABOVE NORMAL IN THE SOUTH. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... 1016-1018 MB SFC HIGH PRESSURE BUILD NEWD ACROSS THE STATE TUESDAY NIGHT WITH FAIR SKIES...LIGHT WIND...AND CHILLY TEMPS MAINLY IN THE 20S. A FAIRLY AMPLIFIED...SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA. SIGNIFICANT PHASING OF THESE BRANCHES FOR A BRIEF TIME OVER THE UPCOMING WEEKEND...WILL USHER IN A BLAST OF VERY COLD AIR WITH TRAJECTORIES RIGHT FROM THE ARCTIC CIRCLE. THE PRIMARY FEATURE OF CONCERN TO BEGIN THIS PERIOD WILL BE LINKED TO THE NOSE OF A QUITE POWERFUL UPPER JET /IN EXCESS OF 140 KTS/ LIFTING NE UP THE APPALACHIAN MTN CHAIN WEDNESDAY. THE INCREASINGLY DIFFLUENT UPPER PATTERN ACROSS THE MID ATLANTIC REGION LATER WED AND WED NIGHT...WILL COMBINE WITH A SLIGHTLY ANOMALOUS SERLY LLVL FLOW AND APPROX 1000 MB SFC LOW PRESSURE CONSOLIDATING/TRACKING RIGHT ACROSS THE DELMARVA REGION AROUND 06Z THURSDAY. SREF AND GEFS PLUMES /OVER THE PAST FEW DAYS/ HAVE GRADUALLY TRENDED TOWARD HIGHER QPF AMTS IN THE FORM OF MAINLY SNOW. EC...CANADIAN AND UKMET ALSO HAVE DISPLAYED A GRADUAL NWD SHIFT TO THE TRACK OF THEIR SFC LOW. USING A BLEND OF ALL THE OPERATIONAL GUIDANCE AND ENSEMBLE MEANS AT HAND PRESENTS US WITH A FAIRLY GOOD CHANCE OF A LIGHT TO MODERATE SNOW EVENT BEGINNING LATE WEDNESDAY AFTERNOON ACROSS THE SWRN HALF OF THE CWA /POSSIBLY MIXED WITH SOME RAIN/...THEN SPREADING NORTH AND EAST AT NIGHT. NUMEROUS SREF AND GEFS PLUMES INDICATE SIGNIFICANT QPF /AOA 0.50 OF AN INCH/ IN THE FORM OF SNOW. SREF/S MEAN 12 HOUR QPF IS AROUND 0.50 ACROSS THE EXTREME SE PART OF THE CWA...WITH THE 0.25 INCH LIQUID EQUIVALENT LINE EXTENDING ALONG MUCH OF INTERSTATE 80 IN CENTRAL PA...THEN ACROSS THE NRN POCONOS. THE 06Z NAM CONTINUES TO TREND TWD HIGHER QPF AS THE MOST AGGRESSIVE MODEL SOLUTION ATTM...AND COMPARABLE WITH SEVERAL OF THE 03Z SREF/ 00Z GEFS PLUMES. THE NAM/S 24-HOUR QPF /FROM ITS APPARENT MILLER B TYPE STORM/ IS AROUND 0.25 INCH ACROSS THE NRN TIER OF PENN...ABOUT 0.50 NEAR I-80...AND OVER 0.75 OF AN INCH ACROSS PORTIONS OF THE LOWER SUSQ REGION. THIS MAGNITUDE OF AN EVENT WOULD BE SOLIDLY IN THE ADVISORY RANGE...WITH POSSIBLY BORDERLINE WINTER STORM WARNING AMOUNTS ACROSS THE SRN HALF OF THE CWA. AT THIS POINT...CONSIDERING MUCH UNCERTAINTY WITH RESPECT TO THE EXACT SECONDARY LOW DEVELOPMENT NEAR THE VA COAST...AND INTERACTION OF THE NRN AND SRN STREAM WAVES...ITS PRUDENT TO RAMP UP THE SNOW PROBABILITIES AND AMOUNTS GRADUALLY...AND HEIGHTEN AWARENESS IN OUR HAZARDOUS WEATHER OUTLOOK /PHLHWOCTP/. A BRIEF PERIOD OF ZONAL FLOW ALOFT AND WEAK SFC HIGH PRESSURE WILL BRING FAIR/MAINLY DRY WEATHER FOR THURSDAY...BEFORE A STRONG NRN STREAM SHORTWAVE AND ASSOCIATED 135 KT...300 MB JET DIVER SEWRD TO CARVE OUT A HIGH AMPLITUDE TROUGH ACROSS THE EASTERN THIRD OF THE U.S. FOR THE WEEKEND. EC SHOWS 500 MB TEMPS FROM THE OHIO VALLEY TO PENN DIVING TO PERHAPS THE COLDEST VALUES OF THE WINTER SEASON...OR AROUND -42C. 850 MB TEMPS MAY DROP TO -16-20C. WEST TO NW MEAN LLVL FLOW AND THE HIGHLY ANOMALOUS COLD AIR IMPLIES A SIGNIFICANT AND PROLONGED LES/UPSLOPE SNOW EVENT FOR THE WRN MTNS AND LAKE ERIE SNOWBELT COUNTIES. BROAD UPPER TROFFING OVER THE EASTERN U.S. WILL LEAD TO YET ANOTHER EAST COAST CYCLONE LATER IN THE WEEKEND. AT THIS POINT IN TIME...THE TRACK IS WELL OFFSHORE...AT LEAST CONCERNING AFFECTS ON PA. WRAP AROUND FLOW IS EVEN SIGNIFICANTLY NORTHERLY...PREVENTING WIDESPREAD LAKE EFFECT SNOW SHOWER ON THE BACK SIDE. IT HOWEVER WOULD SUPPORT AN EXTENDED COLD SPELL AS WE HEAD INTO MID FEBRUARY. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... IFR/MVFR CONDITIONS WILL IMPROVE AS THE DRY AIR MOVES THRU FOR THE REMAINDER OF THE AFTERNOON AND WINDS SHIFT TO THE WEST. EXPECT THE FRONT TO CLEAR EASTERN AREAS THIS EVENING WITH WESTERLY WINDS INCREASING OVER THE REGION...GUSTING IN EXCESS OF 30KTS LATE TONIGHT INTO EARLY TUES OVER WESTERN HIGH TERRAIN. SOME PEAK GUSTS MAY EXCEED 40KTS. THE STRONG WINDS WILL DIRECT COLDER AIR INTO THE REGION WITH SOME SNOW SHOWERS LIKELY ALONG THE ALLEGHENY FRONT AND DOWNWIND OF LAKE ERIE. BLUSTERY POST-FRONTAL REGIME WILL DOMINATE INTO TUES WITH LOWEST CIGS OVR THE NRN AND WRN MTNS. OUTLOOK... TUE...MVFR CIGS NORTH/WEST...BECOMING VFR BY MID DAY. VFR ELSEWHERE WITH A SLOWLY DIMINISHING NW WIND ALL AREAS. WED-THU...VFR EARLY. IFR/SN DEVELOPING OVER THE SOUTHERN HALF OF THE AREA LATER WED INTO EARLY THU AS A LOW PRESSURE SYSTEM TRACKS OFF THE MID ATL COAST. FRI-SAT...MVFR WITH SNOW SHOWERS WEST. VFR EAST. && .CTP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 8 PM THIS EVENING TO 9 AM EST TUESDAY FOR PAZ004>006-010>012-017-018-024-025-033-034. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD/LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...LA CORTE
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AREA FORECAST DISCUSSION
NWS SPOKANE WA
217 PM PST Mon Feb 11 2013 .SYNOPSIS... Moist westerly flow aloft over the region will bring a prolonged period of occasional light mountain snow and a chance of valley rain to mainly far eastern Washington and North Idaho tonight through Thursday. The remainder of the next week will be seasonably cool with a few minor storm systems bringing light mountain snow and valley rain or snow mainly on Saturday and again by late next Monday. && .DISCUSSION... Tonight through Tuesday: An upper level shortwave trough located at 150W in the Gulf of Alaska will flatten out the ridge of high pressure protruding over the region off the eastern pacific. We are already beginning to see some high cloud cover pushing in over the region as some weak isentropic ascent will continue to develop at mid to low levels through tonight, especially across the eastern half of the forecast area with an emphasis in the ID Panhandle. Isentropic ascent will be weak enough with downsloping off the Cascades a factor that I don`t think we will see much in the way of precipitation if any away from the Cascade crest into the Columbia Basin. Extreme eastern WA and into the Idaho Panhandle where upslope flow will help generate some more lift will be the area to watch out for some light snowfall. Best chances for snow will be late tonight into Wednesday as the atmosphere moistens from the top down. It will take some time before snow begins to fall as it will likely evaporate until the mid level cloud deck lowers enough through the night. We could see some seeder feeder development as ice crystals fall into the stratus cloud cover across the valleys in these areas. This would act to enhance snowfall rates in some areas. However, without much in the way of any upper level dynamics to support the isentropic component to this system, I expect snowfall accumulations to be light overall; but, we could see an inch or two of snowfall over Lookout Pass by Wednesday afternoon with another inch or two possible heading over Stevens Pass. Tuesday night through Wednesday: The shortwave trough over the Gulf of Alaska will swing through on Tuesday night. This will result in some better dynamics with a better chance for more significant snowfall accumulations over the Cascade Crest and over into the ID Panhandle. Snow levels will be rising and accumulating snowfall is expected primarily above 3,000 feet with rain in the valleys. Northwest flow will focus the heaviest snowfall in the mountains across the Central Panhandle and into the Camas Prairie by Wednesday. The atmosphere will not be particularly unstable, so I am not expecting bursts of heavy snowfall accumulations. However, steady light snowfall could produce up to around 4 to 6 inches over a 24 hour window Thursday evening through Wednesday evening above 3,500 feet. This will result in more accumulating snowfall along I-90 over Lookout Pass. Winds will be a little breezy, especially up in the mountains as a surface low develops in the eastern Gulf of Alaska ahead of the upper level wave and traverses across northern BC and northern Alberta. Models are now placing the low a bit further north than in previous runs, so the possibility of stronger winds do not look as likely. The resulting pressure gradient will generate winds out of the southwest, which will draw in some warmer air (hence the rising snow levels). This will also result in temperatures a bit warmer Tuesday night into Wednesday. /SVH Wednesday Night and Thursday: Very little changes in the pattern from the previous periods are expected as a ridge continues to dominate our weather pattern. With the ridge we will continue to see the NW flow come over the top of the ridge and across the region. Continued moisture from Wednesday will bring snowfall to the Cascade Crests and to the mountains of mainly the Central ID Panhandle. Valleys in the Central Panhandle will likely see rain showers or a mix of wet snow and rain. Continued accumulations in the higher elevations could lead to some decent snow totals throughout the beginning and middle part of the week. The main forcing associated with the tail end of this prolonged period of snow showers looks to be topographical which should keep snow to mainly lighter intensities. When dealing with the QPF for these periods the models are in agreement for the western part of the forecast area but are struggling with the Panhandle. GFS currently has a much more significant amount of moisture in the region compared to the drier ECMWF. Due to the inconsistencies of the GFS I went closer to the Euro solution with the lighter amount of QPF as this moist flow starts to exit the region. Towards the end of the period on Thursday models show a drying trend that will put a stop to most of snow in the Panhandle as the ridge slowly moves inland and the moisture stream moves to the east of the forecast area. Temperatures during these periods become difficult as sky conditions play a large role as to what we see for highs and lows. Clearing during the nighttime will allow temps to plummet whereas clearing in the daytime will allow temps to warm to higher values than with cloudy skies. With the ridge in place we could see some clearing making temps a tough call. Based on no major changes in models kept temps similar to previous forecast and will have to continue watching trends in cloud cover to help pin down temps. /Fliehman Thursday night through Monday...A progressive late winter pattern with a couple minor precipitation bearing waves and some dry days is advertised by the latest medium range forecast runs. There is good agreement between the GFS/ECMWF and Canadian models depicting a ridge aloft Thursday night through Friday with no compelling reason to expect anything beyond some late night/early morning valley and basin fog with seasonably cool temperatures. Saturday looks like the most active and potentially stormy day of the extended period with model agreement continuing...and depicting the approach and passage of a fairly strong but quick moving upper level trough. Because of the speed of this transient system...P-type will be dependent on the time of passage...with an early arrival overnight Friday and Saturday morning bringing light snow accumulations to much of the region...but if the arrival is slowed down by 6 or 8 hours to impact the area during the afternoon then mainly mountain snow with valley/basin rain showers are more likely. It is too far out to pin the exact timing down...but confidecne is high that Saturday will feature a weather producing system. On Sunday and into Monday the next short wave ridge is expected with dry and potentially foggy conditions once again...and the next short wave expected to enter the region on or about late Monday. Temperatures in this progressive late winter pattern are likely to remain around seasonal average with no stagnant periods or sustained advective patterns to allow any appreciable warm-ups or cool-downs. /Fugazzi && .AVIATION... 18Z TAFS: The western edge of the stratus is following right along the WA/ID border up to the Spokane/Coeur d`Alene areas and is in much of the northern valleys. This has resulted in many of the TAF sites across the region being right on the edge of much of the stratus. Models are not doing a particularly good job of handling the boundary layer moisture. HRRR model shows much of the stratus burning off this afternoon with it having a harder time redeveloping tonight as mid to high level clouds increase over the region. Other model guidance shows this stratus remaining over the region through tomorrow morning. We went with the idea that the stratus will burn off along its western edge with a FEW-BKN deck btwn 2.5 to 4 kft agl from KLWS up to KGEG and BKN-OVC deck at KCOE. This stratus is expected to fill back in toward the west by this evening, but how much it does may be limited by the higher cloud cover moving in aloft ahead of the next system for late tonight into Tuesday. Confidence in stratus coverage is low due to high model uncertainty. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 28 39 32 41 27 38 / 0 20 10 20 10 0 Coeur d`Alene 30 38 32 41 27 38 / 20 40 30 20 10 10 Pullman 30 44 35 46 29 41 / 0 30 30 50 30 20 Lewiston 33 48 37 52 34 46 / 0 20 10 30 30 20 Colville 29 39 32 43 27 40 / 10 20 10 10 10 0 Sandpoint 31 38 33 40 27 36 / 40 50 60 20 20 10 Kellogg 30 39 33 43 29 40 / 30 60 80 70 30 20 Moses Lake 29 46 35 49 28 43 / 0 0 0 0 0 0 Wenatchee 30 44 34 47 30 44 / 0 0 0 0 0 0 Omak 23 40 26 40 25 37 / 10 0 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1008 AM PST Mon Feb 11 2013 .SYNOPSIS... Dry and seasonably cool conditions will prevail through Monday with some patchy fog. The next storm system is expected to arrive on Tuesday bringing light snow mainly to the mountains. The passage of this storm will bring breezy and gusty conditions to the mountains Tuesday night. Mainly dry conditions with seasonal temperatures is expected for the remainder of the week. && .DISCUSSION... Updated the forecast to decrease cloud cover over much of the basin and into the Palouse and Camas Prairie. Satellite imagery this morning is showing much of the stratus banked up in the northern valleys and Panhandle valleys. Light easterly winds downsloping off the mountains into the Palouse and L-C Valley areas has limited the stratus development. Mostly sunny skies are expected through the afternoon hours today. The stratus should burn off a bit from the edges this afternoon with some sun breaks possible late in the afternoon, but mostly cloudy conditions across the northern valleys and into the Panhandle is expected. A weak upper level wave passing across the region with some weak upslope flow into these areas may yield some flurries as well. High clouds will continue to stream over the region ahead of the next wave that is expected to begin to move in tonight with a better chance for some snow, mainly in the Idaho Panhandle and up along the Cascade crest. /SVH && .AVIATION... 18Z TAFS: The western edge of the stratus is following right along the WA/ID border up to the Spokane/Coeur d`Alene areas and is in much of the northern valleys. This has resulted in many of the TAF sites across the region being right on the edge of much of the stratus. Models are not doing a particularly good job of handling the boundary layer moisture. HRRR model shows much of the stratus burning off this afternoon with it having a harder time redeveloping tonight as mid to high level clouds increase over the region. Other model guidance shows this stratus remaining over the region through tomorrow morning. We went with the idea that the stratus will burn off along its western edge with a FEW-BKN deck btwn 2.5 to 4 kft agl from KLWS up to KGEG and BKN-OVC deck at KCOE. This stratus is expected to fill back in toward the west by this evening, but how much it does may be limited by the higher cloud cover moving in aloft ahead of the next system for late tonight into Tuesday. Confidence in stratus coverage is low due to high model uncertainty. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 35 28 39 30 44 26 / 0 0 20 10 20 10 Coeur d`Alene 35 29 38 30 42 26 / 0 10 40 30 20 10 Pullman 38 31 44 34 46 28 / 0 0 30 30 50 20 Lewiston 44 34 48 36 51 33 / 0 0 20 10 30 30 Colville 37 29 39 31 46 26 / 10 10 20 10 10 10 Sandpoint 36 30 38 33 41 26 / 10 20 50 60 20 20 Kellogg 36 29 39 33 42 28 / 10 30 60 70 70 30 Moses Lake 44 29 46 34 48 27 / 0 0 0 0 0 0 Wenatchee 42 30 44 34 47 29 / 0 0 0 0 0 0 Omak 35 24 40 26 42 24 / 0 10 0 10 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$