Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/30/13


AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
1145 AM CDT TUE MAY 28 2013 .DISCUSSION... UPDATED TO INCLUDE THE 18Z AVIATION DISCUSSION BELOW... && .AVIATION... SHRA AND/OR A FEW TSRA WILL BE POSSIBLE ACROSS THE NRN SITES THROUGH THE NEXT FEW HRS...BUT CHANCES WILL DIMINISH BEYOND THAT TIME FRAME. HOWEVER...SOME ISOLATED AFTERNOON PRECIP ACTIVITY COULD STILL BE POSSIBLE. OTHER THAN SOME LOW CIGS/FOG DURING THE OVERNIGHT PERIOD...AND SOME BREEZY SRLY WINDS...VFR CONDITIONS SHOULD PREVAIL. && PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 28 2013/ SHORT TERM...TODAY THROUGH SUNDAY REGIONAL RADAR OBSERVATIONS SHOW SOME DEVELOPING ISOLATED SHOWER ACTIVITY STRETCHING FROM WEST OF FORT SMITH UP THROUGH HARRISON. THE HRRR MODEL HAS A VERY GOOD HANDLE ON THIS AND SHOWS THIS ACTIVITY CONTINUING TO DEVELOP/EXPAND AS IT MOVES EAST ACROSS THE NORTHERN PARTS OF ARKANSAS. WENT AHEAD AND INCLUDED SOME SLIGHT CHANCE POPS FOR SHOWERS THROUGH MIDDAY. OTHERWISE TODAY SHOULD BE DRY. HIGH TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY...IF NOT A DEGREE WARMER IN HIGHER ELEVATIONS. ALOFT...AN UPPER TROUGH IS BEGINNING TO TAKE SHAPE OUT WEST. THE TROUGH AXIS WILL GRADUALLY SHIFT EAST THROUGH THE END OF THE WEEK. IMPULSES EJECTING FROM THIS UPPER TROUGH WILL GENERATE CONVECTION EAST OF A SURFACE LOW AND DRY LINE SETUP STRETCHING FROM THE HIGH PLAINS OF COLORADO AND WESTERN KANSAS DOWN INTO THE PANHANDLE OF TEXAS. AS THE UPPER TROUGH SHIFTS EAST...THESE IMPULSES AND THEIR ASSOCIATED CONVECTION WILL DO THE SAME. SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAY EXIST IN SE ARKANSAS TOMORROW MORNING AS MOISTURE TRANSPORT STRENGTHENS...BUT BETTER RAIN CHANCES WILL MOVE INTO WESTERN ARKANSAS WED EVENING AS ONE OF THE AFOREMENTIONED IMPULSES MOVES THROUGH THE SOUTHERN PLAINS. EXPECT THERE WILL BE SOME ONGOING CONVECTION PRESENT ACROSS MUCH OF THE NWRN HALF OF THE STATE BY THURSDAY MORNING...WHICH IS WHEN THE HIGHEST RAIN CHANCES OF THE SHORT TERM WILL EXIST. CLOUD COVER AND RAIN COOLED AIR MAY DISRUPT DIURNAL THUNDERSTORM DEVELOPMENT THU AFTERNOON...BUT GUIDANCE SHOWS ANOTHER SHORTWAVE AND ASSOC SURFACE LOW MOVING EAST ACROSS OKLAHOMA THU NIGHT. THERE COULD BE SOME MCS ACTIVITY MOVING THROUGH NW ARKANSAS AND SRN MISSOURI LATE THU NIGHT AS A RESULT. FRIDAY LOOKS TO BE DRY WITH ONLY AFTERNOON CU FOR CLOUD COVER. TEMPERATURES WED THROUGH FRIDAY WILL BE SLIGHTLY BELOW NORMAL FOR THE NORTHWEST HALF OF THE STATE BUT SHOULD BE CLOSE TO CLIMATOLOGICAL NORMS FOR THE SOUTHEAST. LONG TERM...SATURDAY THROUGH MONDAY TO START THE EXTENDED...THE BROAD UPPER LOW PRESSURE TROUGH IS EXPECTED TO SETTLE SE TO THE CENTRAL PLAINS...AS A SURFACE COLD FRONT ALSO DRIFTS TO THE PLAINS. THE UPPER SW FLOW WILL BRING SHORT WAVE ENERGY TO AR AND A CHANCE OF CONVECTION IS EXPECTED OVER ALL OF AR. ADDITIONAL RAIN IS EXPECTED SATURDAY NIGHT AND SUNDAY...AS THE COLD FRONT SAGS INTO AR AND ADDITIONAL UPPER ENERGY MOVES OVER AR. AREAS OF HEAVY RAIN MAY BE POSSIBLE. SUNDAY NIGHT...THE COLD FRONT GRADUALLY SAGS SOUTH TO NEAR THE AR AND LA STATE LINE...AS THE UPPER TROUGH BOTTOMS OUT OVER THE TN VALLEY. ON MONDAY...DRIER AND A BIT COOLER TEMPS ARE EXPECTED AS THE UPPER TROUGH MOVES EAST AND UPPER RIDGING GRADUALLY MOVES INTO THE REGION. SOME UNCERTAINTY DOES EXIST ON HOW FAR THE UPPER TROUGH TAKES THE COLD FRONT. IT IS THE END OF MAY AND A BIT UNUSUALLY TO HAVE A COLD FRONT PUSH THIS FAR SOUTH. TEMPERATURES WILL BE AROUND NORMAL VALUES...THEN COOL A BIT IF THE AIR MASS FILTERS IN BEHIND THE FRONT. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 87 68 86 69 / 10 10 10 30 CAMDEN AR 88 69 87 70 / 10 10 20 20 HARRISON AR 84 67 83 67 / 20 10 20 40 HOT SPRINGS AR 86 69 85 70 / 10 10 20 30 LITTLE ROCK AR 88 70 87 70 / 10 10 10 30 MONTICELLO AR 89 70 86 70 / 10 10 20 20 MOUNT IDA AR 85 68 84 70 / 10 10 20 30 MOUNTAIN HOME AR 86 68 85 68 / 20 10 20 40 NEWPORT AR 88 69 86 70 / 10 10 10 30 PINE BLUFF AR 88 69 86 70 / 10 10 20 20 RUSSELLVILLE AR 87 69 85 69 / 10 10 20 30 SEARCY AR 87 69 86 69 / 10 10 10 30 STUTTGART AR 88 70 86 70 / 10 10 20 20 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AVIATION...62
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NWS LITTLE ROCK AR
630 AM CDT TUE MAY 28 2013 .AVIATION... OVERALL VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS. INCREASING MID AND HIGH CLOUDS...WITH CEILINGS...WILL SPREAD OVER AR TODAY. PATCHY MVFR CONDITIONS WILL BE SEEN THIS MORNING BUT WILL THIN AS WINDS INCREASE THROUGH THE MORNING. A FEW ISOLATED SHOWERS WILL BE POSSIBLE THIS MORNING OVER NORTHERN AR BUT ONLY USED VCSH DUE TO UNCERTAINTY. WINDS WILL BE SE TO S AT 5 TO 15 KNOTS THIS MORNING...THEN BECOME SE TO SW AT 10 TO 20 KNOTS WITH SOME GUSTS TO 25 KNOTS INTO THE AFTERNOON. A LOW LEVEL JET WILL SET UP ACROSS AR AND PRODUCE WIND SHEAR FROM THE S TO SW AT 30 TO 45 KNOTS TO 2000 FEET. (59) && .PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 28 2013/ .SHORT TERM...TODAY THROUGH SUNDAY REGIONAL RADAR OBSERVATIONS SHOW SOME DEVELOPING ISOLATED SHOWER ACTIVITY STRETCHING FROM WEST OF FORT SMITH UP THROUGH HARRISON. THE HRRR MODEL HAS A VERY GOOD HANDLE ON THIS AND SHOWS THIS ACTIVITY CONTINUING TO DEVELOP/EXPAND AS IT MOVES EAST ACROSS THE NORTHERN PARTS OF ARKANSAS. WENT AHEAD AND INCLUDED SOME SLIGHT CHANCE POPS FOR SHOWERS THROUGH MIDDAY. OTHERWISE TODAY SHOULD BE DRY. HIGH TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY...IF NOT A DEGREE WARMER IN HIGHER ELEVATIONS. ALOFT...AN UPPER TROUGH IS BEGINNING TO TAKE SHAPE OUT WEST. THE TROUGH AXIS WILL GRADUALLY SHIFT EAST THROUGH THE END OF THE WEEK. IMPULSES EJECTING FROM THIS UPPER TROUGH WILL GENERATE CONVECTION EAST OF A SURFACE LOW AND DRY LINE SETUP STRETCHING FROM THE HIGH PLAINS OF COLORADO AND WESTERN KANSAS DOWN INTO THE PANHANDLE OF TEXAS. AS THE UPPER TROUGH SHIFTS EAST...THESE IMPULSES AND THEIR ASSOCIATED CONVECTION WILL DO THE SAME. SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAY EXIST IN SE ARKANSAS TOMORROW MORNING AS MOISTURE TRANSPORT STRENGTHENS...BUT BETTER RAIN CHANCES WILL MOVE INTO WESTERN ARKANSAS WED EVENING AS ONE OF THE AFOREMENTIONED IMPULSES MOVES THROUGH THE SOUTHERN PLAINS. EXPECT THERE WILL BE SOME ONGOING CONVECTION PRESENT ACROSS MUCH OF THE NWRN HALF OF THE STATE BY THURSDAY MORNING...WHICH IS WHEN THE HIGHEST RAIN CHANCES OF THE SHORT TERM WILL EXIST. CLOUD COVER AND RAIN COOLED AIR MAY DISRUPT DIURNAL THUNDERSTORM DEVELOPMENT THU AFTERNOON...BUT GUIDANCE SHOWS ANOTHER SHORTWAVE AND ASSOC SURFACE LOW MOVING EAST ACROSS OKLAHOMA THU NIGHT. THERE COULD BE SOME MCS ACTIVITY MOVING THROUGH NW ARKANSAS AND SRN MISSOURI LATE THU NIGHT AS A RESULT. FRIDAY LOOKS TO BE DRY WITH ONLY AFTERNOON CU FOR CLOUD COVER. TEMPERATURES WED THROUGH FRIDAY WILL BE SLIGHTLY BELOW NORMAL FOR THE NORTHWEST HALF OF THE STATE BUT SHOULD BE CLOSE TO CLIMATOLOGICAL NORMS FOR THE SOUTHEAST. && .LONG TERM...SATURDAY THROUGH MONDAY TO START THE EXTENDED...THE BROAD UPPER LOW PRESSURE TROUGH IS EXPECTED TO SETTLE SE TO THE CENTRAL PLAINS...AS A SURFACE COLD FRONT ALSO DRIFTS TO THE PLAINS. THE UPPER SW FLOW WILL BRING SHORT WAVE ENERGY TO AR AND A CHANCE OF CONVECTION IS EXPECTED OVER ALL OF AR. ADDITIONAL RAIN IS EXPECTED SATURDAY NIGHT AND SUNDAY...AS THE COLD FRONT SAGS INTO AR AND ADDITIONAL UPPER ENERGY MOVES OVER AR. AREAS OF HEAVY RAIN MAY BE POSSIBLE. SUNDAY NIGHT...THE COLD FRONT GRADUALLY SAGS SOUTH TO NEAR THE AR AND LA STATE LINE...AS THE UPPER TROUGH BOTTOMS OUT OVER THE TN VALLEY. ON MONDAY...DRIER AND A BIT COOLER TEMPS ARE EXPECTED AS THE UPPER TROUGH MOVES EAST AND UPPER RIDGING GRADUALLY MOVES INTO THE REGION. SOME UNCERTAINTY DOES EXIST ON HOW FAR THE UPPER TROUGH TAKES THE COLD FRONT. IT IS THE END OF MAY AND A BIT UNUSUALLY TO HAVE A COLD FRONT PUSH THIS FAR SOUTH. TEMPERATURES WILL BE AROUND NORMAL VALUES...THEN COOL A BIT IF THE AIR MASS FILTERS IN BEHIND THE FRONT. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 87 68 86 69 / 10 10 10 30 CAMDEN AR 88 69 87 70 / 10 10 20 20 HARRISON AR 84 67 83 67 / 10 10 20 40 HOT SPRINGS AR 86 69 85 70 / 10 10 20 30 LITTLE ROCK AR 88 70 87 70 / 10 10 10 30 MONTICELLO AR 89 70 86 70 / 10 10 20 20 MOUNT IDA AR 85 68 84 70 / 10 10 20 30 MOUNTAIN HOME AR 86 68 85 68 / 20 10 20 40 NEWPORT AR 88 69 86 70 / 10 10 10 30 PINE BLUFF AR 88 69 86 70 / 10 10 20 20 RUSSELLVILLE AR 87 69 85 69 / 10 10 20 30 SEARCY AR 87 69 86 69 / 10 10 10 30 STUTTGART AR 88 70 86 70 / 10 10 20 20 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...64 / LONG TERM...59
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
325 AM CDT TUE MAY 28 2013 .SHORT TERM...TODAY THROUGH SUNDAY REGIONAL RADAR OBSERVATIONS SHOW SOME DEVELOPING ISOLATED SHOWER ACTIVITY STRETCHING FROM WEST OF FORT SMITH UP THROUGH HARRISON. THE HRRR MODEL HAS A VERY GOOD HANDLE ON THIS AND SHOWS THIS ACTIVITY CONTINUING TO DEVELOP/EXPAND AS IT MOVES EAST ACROSS THE NORTHERN PARTS OF ARKANSAS. WENT AHEAD AND INCLUDED SOME SLIGHT CHANCE POPS FOR SHOWERS THROUGH MIDDAY. OTHERWISE TODAY SHOULD BE DRY. HIGH TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY...IF NOT A DEGREE WARMER IN HIGHER ELEVATIONS. ALOFT...AN UPPER TROUGH IS BEGINNING TO TAKE SHAPE OUT WEST. THE TROUGH AXIS WILL GRADUALLY SHIFT EAST THROUGH THE END OF THE WEEK. IMPULSES EJECTING FROM THIS UPPER TROUGH WILL GENERATE CONVECTION EAST OF A SURFACE LOW AND DRY LINE SETUP STRETCHING FROM THE HIGH PLAINS OF COLORADO AND WESTERN KANSAS DOWN INTO THE PANHANDLE OF TEXAS. AS THE UPPER TROUGH SHIFTS EAST...THESE IMPULSES AND THEIR ASSOCIATED CONVECTION WILL DO THE SAME. SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAY EXIST IN SE ARKANSAS TOMORROW MORNING AS MOISTURE TRANSPORT STRENGTHENS...BUT BETTER RAIN CHANCES WILL MOVE INTO WESTERN ARKANSAS WED EVENING AS ONE OF THE AFOREMENTIONED IMPULSES MOVES THROUGH THE SOUTHERN PLAINS. EXPECT THERE WILL BE SOME ONGOING CONVECTION PRESENT ACROSS MUCH OF THE NWRN HALF OF THE STATE BY THURSDAY MORNING...WHICH IS WHEN THE HIGHEST RAIN CHANCES OF THE SHORT TERM WILL EXIST. CLOUD COVER AND RAIN COOLED AIR MAY DISRUPT DIURNAL THUNDERSTORM DEVELOPMENT THU AFTERNOON...BUT GUIDANCE SHOWS ANOTHER SHORTWAVE AND ASSOC SURFACE LOW MOVING EAST ACROSS OKLAHOMA THU NIGHT. THERE COULD BE SOME MCS ACTIVITY MOVING THROUGH NW ARKANSAS AND SRN MISSOURI LATE THU NIGHT AS A RESULT. FRIDAY LOOKS TO BE DRY WITH ONLY AFTERNOON CU FOR CLOUD COVER. TEMPERATURES WED THROUGH FRIDAY WILL BE SLIGHTLY BELOW NORMAL FOR THE NORTHWEST HALF OF THE STATE BUT SHOULD BE CLOSE TO CLIMATOLOGICAL NORMS FOR THE SOUTHEAST. && .LONG TERM...SATURDAY THROUGH MONDAY TO START THE EXTENDED...THE BROAD UPPER LOW PRESSURE TROUGH IS EXPECTED TO SETTLE SE TO THE CENTRAL PLAINS...AS A SURFACE COLD FRONT ALSO DRIFTS TO THE PLAINS. THE UPPER SW FLOW WILL BRING SHORT WAVE ENERGY TO AR AND A CHANCE OF CONVECTION IS EXPECTED OVER ALL OF AR. ADDITIONAL RAIN IS EXPECTED SATURDAY NIGHT AND SUNDAY...AS THE COLD FRONT SAGS INTO AR AND ADDITIONAL UPPER ENERGY MOVES OVER AR. AREAS OF HEAVY RAIN MAY BE POSSIBLE. SUNDAY NIGHT...THE COLD FRONT GRADUALLY SAGS SOUTH TO NEAR THE AR AND LA STATE LINE...AS THE UPPER TROUGH BOTTOMS OUT OVER THE TN VALLEY. ON MONDAY...DRIER AND A BIT COOLER TEMPS ARE EXPECTED AS THE UPPER TROUGH MOVES EAST AND UPPER RIDGING GRADUALLY MOVES INTO THE REGION. SOME UNCERTAINTY DOES EXIST ON HOW FAR THE UPPER TROUGH TAKES THE COLD FRONT. IT IS THE END OF MAY AND A BIT UNUSUALLY TO HAVE A COLD FRONT PUSH THIS FAR SOUTH. TEMPERATURES WILL BE AROUND NORMAL VALUES...THEN COOL A BIT IF THE AIR MASS FILTERS IN BEHIND THE FRONT. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 87 68 86 69 / 10 10 10 30 CAMDEN AR 88 69 87 70 / 10 10 20 20 HARRISON AR 84 67 83 67 / 10 10 20 40 HOT SPRINGS AR 86 69 85 70 / 10 10 20 30 LITTLE ROCK AR 88 70 87 70 / 10 10 10 30 MONTICELLO AR 89 70 86 70 / 10 10 20 20 MOUNT IDA AR 85 68 84 70 / 10 10 20 30 MOUNTAIN HOME AR 86 68 85 68 / 20 10 20 40 NEWPORT AR 88 69 86 70 / 10 10 10 30 PINE BLUFF AR 88 69 86 70 / 10 10 20 20 RUSSELLVILLE AR 87 69 85 69 / 10 10 20 30 SEARCY AR 87 69 86 69 / 10 10 10 30 STUTTGART AR 88 70 86 70 / 10 10 20 20 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...64 / LONG TERM...59
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1054 PM PDT MON MAY 27 2013 .DISCUSSION...AS OF 8:47 PM PDT MONDAY...IT WAS A COOL AND CLOUDY MEMORIAL DAY FOR MOST OF THE DISTRICT AS A WEAK LATE SEASON COLD FRONT MOVED THROUGH NORTHERN CALIFORNIA. RAIN TOTALS WERE SPOTTY AND LIGHT WITH MOST SITES REPORTING FROM A TRACE TO A FEW HUNDREDTHS. JUST SENT OUT A PUBLIC INFORMATION STATEMENT SHOWING SOME OF THE TOTALS ACROSS THE DISTRICT INCLUDING SOME OF THE REMOTE GAGES UP IN THE HILLS. LAST VISIBLE SATELLITE IMAGES STILL SHOW PLENTY OF MOISTURE OFF SHORE AND VARIOUS AMSU/SSMI SATELLITE SCANS SHOW TONGUE OF MOISTURE JUST SOUTH OF 40N...WITH TPW VALUES WELL IN EXCESS OF 1 INCH. LATEST DOPPLER RADAR SCANS ARE STILL SHOWING SOME ISOLATED SHOWERS MOVING ONSHORE IN ACCORDANCE WITH SATELLITE IMAGERY...AND KSTS REPORTING -RA WITH LAST OBSERVATION. INCOMING HIGH RESOLUTION RAP MODEL KEEPS SPITTING OUT SOME VERY LIGHT QPF NUMBERS OVERNIGHT...MAINLY IN THE NORTH BAY AND ALONG THE COAST. UPSHOT IS THAT CURRENT FORECAST KEEPS SOME SLIGHT CHANCE OF SHOWERS GOING THROUGH THE OVERNIGHT AND SEE NO NEED TO ALTER THAT FORECAST. BACK TO WORK TUESDAY THE REGION WILL BE POST-FRONTAL WITH BREEZY ONSHORE WINDS. HIGHS AGAIN WILL MAINLY BE IN THE 60S NEAR THE COAST AND BAYS WITH ONLY LOW TO MID 70S FOR MOST INLAND LOCATIONS WHICH IS ABOUT 5 DEGREES BELOW NORMAL FOR LATE MAY. EXPECTING MORE SUNSHINE BY THE AFTERNOON HOURS COMPARED TO TODAY. LATE TUESDAY NIGHT INTO WEDS ANOTHER SIMILAR LATE SEASON COLD FRONT WILL APPROACH FAR NORTHERN CALIFORNIA. MODELS HAVE BEEN FAIRLY CONSISTENT IN BRINGING THE RAIN/NO-RAIN LINE TO FAR NORTHERN SONOMA COUNTY. FORECAST HAS THIS ACCOUNTED FOR AND ANY RAIN THAT FALLS ON WEDS MORNING WILL BE LIGHT AND BRIEF AS THE FRONT WILL QUICKLY MOVE INLAND DURING THE DAY WEDS. SO ONLY REAL PRECIP THREAT FOR WEDS LOOKS TO BE NORTH OF SANTA ROSA WITH PARTLY CLOUDY SKIES AND SEASONABLE TEMPS FOR THE REST OF THE REGION. ZONAL FLOW WITH ONSHORE WINDS WILL CONTINUE ON THURSDAY BUT TEMPS WILL NUDGE A FEW DEGREES WARMER TO RIGHT AROUND SEASONABLE NORMALS. BIG WEATHER STORY FRIDAY AND INTO THE WEEKEND WILL THEN BE A NOTED WARMING AND DRYING TREND. A STRONG RIDGE WILL DEVELOP OVER THE STATE WITH UNSETTLED WEATHER EAST OF THE ROCKIES AMPLIFYING THE 500 MB PATTERN. A 590 DM HIGH OVER THE EASTERN PACIFIC AND ASSOCIATED 850 MB TEMPS OF AROUND 22 CELSIUS BY SATURDAY OVER THE BAY AREA. SO EXPECT RAPID WARMING ON FRIDAY AND SATURDAY WITH MOSTLY CLEAR SKIES...EVEN AT THE BEACHES AS THE THERMAL TROUGH STRADDLES THE COAST WITH PERIODS OF LIGHT TO MODERATE NORTHERLY WINDS DEVELOPING IN THE HILLS. ECMWF MOS DATA IS GETTING OMINOUSLY CLOSE TO SOME WIDESPREAD TRIPLE DIGIT HEAT BY SATURDAY FOR THE INLAND VALLEYS OR AT THE VERY LEAST LOTS OF 90S. SHOULD THE PATTERN DEVELOP AS EXPECTED FIRE WEATHER CONCERNS WILL BECOME ELEVATED ESPECIALLY IN LIGHT OF VERY DRY FUELS ACROSS THE REGION AND STATE. MODELS SPIN UP A WEAK CIRCULATION BY SUNDAY WHICH WOULD LIKELY INDUCE A SOUTHERLY WIND REVERSAL AND COASTAL COOLING...FOLLOWED BY INLAND COOLING NEXT MONDAY. && .AVIATION...AS OF 10:40 PM PDT MONDAY...MOIST FLOW OFF EPAC CONTINUES SUPPORTED BY AREA DEWPOINT TEMPERATURES IN THE 50S...TOTAL PRECIPITABLE WATERS OVER 1 INCH (200% OF NORMAL)...AND SATELLITE IMAGERY SHOWING MORE CLOUDS SPILLING INTO THE REGION. AREA RAIN GAUGES NOW SHOW UPWARDS OF 0.30 INCHES AT POINT REYES AND 0.17 INCHES AT THE SANTA ROSA RAWS...AND 0.02 INCHES IN SAN FRANCISCO. KMUX RADAR SHOWS STEADY LIGHT RAIN CONTINUING TO SPREAD SOUTHEAST. VICINITY OF KSFO...WET RUNWAYS AND LIGHT WINDS TONIGHT. IT`S A LOW CONFIDENCE FORECAST SINCE THE MODELS ARE UNDERESTIMATING RAINFALL AMOUNTS SO FAR. PARTIAL CLEARING PROBABLE TUE AFTERNOON WITH THE SFO-SAC PRESSURE GRADIENT INCREASING TO 4 MB. GUSTY WEST WINDS ARE POSSIBLE TUE AFTERNOON AND EVENING. KSFO BRIDGE APPROACH...WET WEATHER TONIGHT. CIGS POSSIBLY LOWERING TO MVFR. MONTEREY BAY AREA TERMINALS...LOW CONFIDENCE. PLENTY OF MOIST AIR ROLLING OFF THE OCEAN LEADING TO MVFR CIGS AND EVENTUALLY IFR CIGS. LIGHT RAIN POSSIBLE OVERNIGHT. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM && $$ PUBLIC FORECAST: RWW AVIATION/MARINE: CANEPA VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS NEW YORK NY
808 PM EDT WED MAY 29 2013 .SYNOPSIS... A WARM FRONT MOVES NORTH OF THE AREA TONIGHT. A BERMUDA HIGH PRESSURE DOMINATES THE WEATHER THURSDAY THROUGH SATURDAY NIGHT. A COLD FRONT APPROACHES SUNDAY AND MOVES THROUGH THE REGION MONDAY. CANADIAN HIGH PRESSURE THEN BUILDS IN MONDAY NIGHT THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... SEVERE THUNDERSTORM WATCH FOR ORANGE AND PUTNAM COUNTIES UNTIL 03Z. LINE OF SHOWERS AND THUNDERSTORMS MOVING SOUTHEAST OVER SOUTHERN NY AND NORTHEASTERN MA WILL MOST LIKELY MOVE INTO NORTHERN ZONES TONIGHT...AFTER 01Z. THE HRRR LOOKED LIKE IT HAD THE BEST HANDLE OF THE STORMS. THESE STORMS ARE STRONG TO SEVERE...AND WITH 1000-2000 J/KG OF CAPE SEEN IN LAPS IN ORANGE AND PUTNAM COUNTIES...THERE STILL EXISTS THE POSSIBILITY THAT THIS LINE MAY HOLD TOGETHER. IT WILL ALSO MAKE ITS WAY INTO CT...BUT WITH LESS IN THE WAY OF CAPE...STORMS SHOULD WEAKEN AS THEY APPROACH THIS REGION. HOWEVER...GUSTY WINDS...SMALL HAIL AND HEAVY RAIN ARE STILL POSSIBILITIES...ALONG WITH AN ISOLATED SEVERE STORM. THE WARM FRONT IS LIFTING NORTH ACROSS THE CWA THIS AFTERNOON. A SHORTWAVE TROUGH IS ALSO APPROACHING FROM THE WEST AND WILL CROSS THE REGION THIS EVENING. CLOUD COVER CONTINUES TO ERODE ALLOWING FOR TEMPERATURES TO WARM AND INSTABILITY LEVELS TO INCREASE FAIRLY RAPIDLY. LATEST SPC MESOANALYSIS INDICATES AROUND 1000 TO 1500 J/KG OF MLCAPE FROM NE NJ AND THE LOWER HUDSON VALLEY. THERE IS VERY LITTLE CONVECTIVE INHIBITION AND INSTABILITY MAY CONTINUE TO INCREASE ACROSS THE AREA THE NEXT FEW HOURS WITH CONTINUED SURFACE HEATING. THE SHORTWAVE IS BEGINNING TO TRIGGER SOME CONVECTION ACROSS NW PA AND UPSTATE NY...SO THIS WILL NEED TO MONITORED AS IT APPROACHES. PORTIONS OF THE AREA...MAINLY NORTH OF LONG ISLAND AND NYC...REMAIN IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS THROUGH THE EVENING WITH THE MAIN THREAT DAMAGING WINDS AND HAIL. THIS IS SUPPORTED BY SHEAR VALUES BETWEEN 30 AND 35 KT...MORE FAVORABLE FOR MULTICELL CLUSTERS WITH WIND AND HAIL THREATS. THE STRONGEST CONVECTION COULD BEGIN TO MOVE IN TO OUR NW COUNTIES AROUND 21Z AND SHIFT EAST THROUGH 00Z. INTENSITY OF THE STORMS SHOULD LOWER AS THEY MOVE EAST THIS EVENING WITH LOSS OF DAYTIME HEATING...BUT CHANCE OF A FEW SHOWERS AND STORMS CONTINUES THROUGH 03Z AS THE SHORTWAVE MOVES THROUGH. OTHERWISE...SKY COVER SHOULD GENERALLY BE PARTLY CLOUDY THROUGH THE REST OF THE EVENING. WITH A WARM AIR MASS IN PLACE TONIGHT...TEMPERATURES WILL ONLY FALL INTO THE 60S AND A MAV/MET BLEND ACCEPTED HERE. SOME PATCHY FOG IS POSSIBLE TOWARDS DAYBREAK. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/... DEEP LAYERED RIDGING BEGINS TO TAKES HOLD THURSDAY WITH A BERMUDA HIGH RIDGING INTO THE AREA. WEIGHTED HIGH TEMPERATURES MORE TOWARDS MET GUIDANCE BUT DID BLEND IN THE MAV GUIDANCE. THIS YIELDS HIGHS IN UPPER 80S AND LOWER 90S...WARMEST ACROSS THE NYC METRO. HEAT INDEX VALUES ARE EXPECTED TO STAY BELOW ADVISORY CRITERIA. MODEL GUIDANCE DOES INDICATE A WEAK SHORTWAVE GLANCING OUR NORTHERN COUNTIES DURING THE TIME OF MAX HEATING. IT IS HERE WHERE A SLIGHT CHANCE OF A SHOWER OR STORM EXISTS. DEEP RIDGING CONTINUES THURSDAY NIGHT INTO FRIDAY. TEMPERATURES THURSDAY NIGHT WILL BE AROUND TEN DEGREES ABOVE AVERAGE IN THE 60S AND LOWER 70S IN THE CITY. FOR FRIDAY...TEMPERATURES MAY BE A FEW DEGREES WARMER THAN THURSDAY IN THE CITY...WITH HEAT INDEX VALUES TOUCHING 95 OR 96 FOR A FEW HOURS. UPPER 80S AND LOWER 90S EXPECTED ELSEWHERE. CONTINUED TO WEIGHT HIGH TEMPERATURES MORE TOWARDS MET GUIDANCE WITH A BLEND OF MAV GUIDANCE. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... FRIDAY NIGHT AND SATURDAY LEANED TOWARD A BLEND OF THE GFS AND ECMWF WITH HIGH PRESSURE REMAINING OVER THE AREA. HOWEVER...WITH THE LOW THAT WILL BE IMPACTING THE AREA SUNDAY INTO MONDAY THE NAM WAS A LITTLE WEAKER THAN THE OTHER MODELS BOTH ALOFT AND AT THE SURFACE. WITH SOME INSTABILITY AND WEAK FORCING POSSIBLE SATURDAY AFTERNOON ACROSS ORANGE COUNTY...AS RIDGE AXIS SLIDES TO THE EAST OF THE AREA...HAVE KEPT IN THE SLIGHT CHANCE POPS FOR THUNDERSTORMS. THEN FOR THE PERIOD SATURDAY NIGHT THROUGH WEDNESDAY FORECAST REMAINS CONSISTENT WITH CURRENT FORECAST...AND THE WPC/ECMWF GUIDANCE. A COLD FRONT APPROACHES SUNDAY AND MOVES SLOWLY THROUGH THE AREA THROUGH MONDAY EVENING. FOR SUNDAY NIGHT AND MONDAY HAVE INCREASED POPS TO LIKELY WITH INCREASING CONFIDENCE IN MEASURABLE PRECIPITATION. DEEP UPPER TROUGH COULD BE A LITTLE SLOWER TO MOVE THROUGH AND PRECIPITATION MAY LINGER A LITTLE LONGER BEHIND THE COLD FRONT MONDAY NIGHT. TEMPERATURES THROUGH THE PERIOD WERE MAINLY A BLEND OF THE PREVIOUS FORECAST AND ECMWF GUIDANCE. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... THE REGION WILL BE OF THE NORTHWEST PERIPHERY OF WESTERN ATLANTIC HIGH PRESSURE THROUGH THE PERIOD. MAINLY VFR THROUGH THE TAF PERIOD. MAIN ACTIVITY WE ARE WATCHING IS A CONVECTIVE LINE OVER CENTRAL NY THAT IS EXPECTED TO CONTINUE TO MOVE SE...WITH ADDITIONAL DEVELOPMENT ON THE SW FLANK. THE LINE IS EXPECTED TO MAINTAIN ITS STRENGTH OVER THE NEXT HOUR OR SO...AND THEN GRADUALLY WEAKEN WITH THE LOSS OF DAYTIME INSTABILITY. EXPECTATION IS THAT THE WEAKENING LINE WILL AFFECT KSWF...AND THEN LIKELY AFFECT KHPN/KBDR THIS EVENING. SHOWER ACTIVITY WILL LIKELY MAINTAIN ITSELF INTO KGON AND POSSIBLY CLIP KISP LATE THIS EVENING. MVFR/IFR FOG IS POSSIBLE OUTSIDE OF NYC TERMINALS TONIGHT. BEST CHANCE ALONG COAST AND TERMINALS AFFECTED BY RAIN. VFR ON WED WITH WSW WINDS TO START THE DAY. WINDS GUST INTO MID TEENS POSSIBLE ACROSS CITY AND INTERIOR TERMINALS IN THE AFTERNOON. MODERATE CONFIDENCE IN AFT SEABREEZE AT KJFK/KISP/KBDR/KGON. LOW CONFIDENCE THAT IT REACHES KLGA/KHPN...AND NOT EXPECTED ELSEWHERE. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: TSRA NOT EXPECTED THIS EVENING. KJFK FCSTER COMMENTS: TSRA NOT EXPECTED THIS EVENING. KLGA FCSTER COMMENTS: TSRA NOT EXPECTED THIS EVENING. KTEB FCSTER COMMENTS: TSRA NOT EXPECTED THIS EVENING. KHPN FCSTER COMMENTS: TSRA POSSIBLE BETWEEN 2Z AND 5Z. KISP FCSTER COMMENTS: SHRA POSSIBLE BTWN 3Z TO 6Z...LOW PROB OF TSRA. .OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY... .THURSDAY NIGHT-FRIDAY...MAINLY VFR. .FRIDAY NIGHT-SATURDAY...MVFR FOG/STRATUS POSSIBLE OVER EASTERN TERMINALS LATE AT NIGHT/EARLY IN THE MORNING. SLIGHT CHANCE OF AFTERNOON/EARLY EVENING SHRA/TSRA FROM CITY TERMINALS ON N AND W. .SATURDAY NIGHT...MAINLY VFR. .SUNDAY-MONDAY...MVFR OR LOWER POSSIBLE IN SHRA/TSRA. && .MARINE... EXPECTING SCA CONDITIONS FROM HAZARDOUS SEAS OVER OCEAN WATERS THROUGH THURSDAY EVENING SO EXTENDED CURRENT SCA FOR ANZ355 AND ANZ353 THROUGH 18Z THURSDAY AND 22Z THURSDAY FOR ANZ350. OTHERWISE...WILL SEE SUB-SCA CONDITIONS FROM THURSDAY NIGHT THROUGH FRIDAY. BERMUDA HIGH PRESSURE WILL REMAIN THROUGH SATURDAY NIGHT. THE HIGH WILL SLOWLY MOVE EAST SUNDAY AS LOW PRESSURE MOVES INTO SOUTHEASTERN CANADA AND A COLD FRONT APPROACHES FROM THE WEST. THE COLD FRONT WILL CROSS THE FORECAST WATERS MONDAY INTO MONDAY EVENING. HIGH PRESSURE BUILDS IN BEHIND THE FRONT MONDAY NIGHT INTO TUESDAY. WIND AND GUSTS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT LEVELS FRIDAY NIGHT THROUGH MONDAY NIGHT. WITH AN INCREASING SOUTHWESTERLY FLOW SATURDAY INTO MONDAY SEAS ON THE OCEAN WILL BUILD TO SMALL CRAFT LEVELS SATURDAY AND REMAIN THROUGH MONDAY. && .HYDROLOGY... NO SIGNIFICANT PRECIPITATION IS EXPECTED TONIGHT THROUGH SUNDAY MORNING. SUNDAY AFTERNOON THROUGH MONDAY EVENING ONE HALF TO ONE INCH OF RAINFALL IS POSSIBLE...WITH LOCALLY HIGHER AMOUNTS IN HEAVIER CONVECTION. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM EDT THURSDAY FOR ANZ353-355. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THURSDAY FOR ANZ350. && $$ SYNOPSIS...DS/MET NEAR TERM...MPS/DS SHORT TERM...MPS/DS LONG TERM...MET AVIATION... MARINE...MPS/DS/MET HYDROLOGY...MPS/DS/MET
AREA FORECAST DISCUSSION
NWS TAUNTON MA
409 PM EDT TUE MAY 28 2013 .SYNOPSIS... RAIN WILL OVERSPREAD THE REGION INTO THE OVERNIGHT HOURS INTO WEDNESDAY MORNING...WITH THE THUNDERSTORMS THEREAFTER INTO WEDNESDAY NIGHT. SUMMER HEAT AND HUMIDITY WILL FOLLOW FOR THURSDAY INTO SUNDAY. AN APPROACHING COLD FRONT FROM THE WEST WILL BRING AN INCREASING THREAT OF SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON INTO MONDAY WITH MORE SEASONABLE TEMPERATURES EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 330 PM UPDATE... THE HRRR IS DOING THE BEST IN HANDLING THE PRECIPITATION SHIELD COLLOCATED WITH THE SURFACE WARM FRONT CENTERED AROUND THE NYC TRI-STATE REGION. FOLLOWING ACCORDINGLY...THE EXPECTATION IS FOR THE BATCH OF RAIN TO SLIDE SOUTH AND EAST UP AGAINST HIGH PRESSURE AND DRIER AIR ACROSS THE ATLANTIC. CHANCE TO LIKELY POPS SHOULD IMPACT MUCH OF CONNECTICUT NORTH INTO SPRINGFIELD AND WORCESTER MASSACHUSETTS INTO THE EVENING COMMUTE. RAIN LOOKS TO GET INTO RHODE ISLAND AROUND 8 PM. NO THUNDERSTORMS ARE ANTICIPATED WITH THE BATCH OF RAIN. RAIN AMOUNTS UPSTREAM ARE PRESENTLY LIGHT WITH HIGHEST VALUES WITHIN AN HOUR OF AROUND ONE- TENTH. TONIGHT... REINVIGORATION OF PRECIPITATION ALONG THE APPROACHING WARM FRONT WILL PROCEED INTO THE OVERNIGHT HOURS AS PRESENT ENERGY ACROSS MICHIGAN PROPAGATES WITH THE MEAN-FLOW ALONG THE NOSE OF A H925-85 JET. THE BULK OF THE ACTIVITY REMAINS NORTH ACROSS CENTRAL AND NORTHERN NEW ENGLAND UP INTO THE SAINT LAWRENCE VALLEY. MAINLY RAIN...THERE IS ALSO THE POSSIBILITY FOR THUNDERSTORMS PARENT WITH THE STRONGLY SHEARED PROFILE. BUT WITH LITTLE TO NO INSTABILITY...THUNDERSTORMS SHOULD BE VERY ISOLATED. JUST A RUMBLE OR TWO OF THUNDER. NO THREATS ARE PERCEIVED...BUT THERE COULD BE POCKETS OF HEAVIER RAIN THAT COULD LEAD TO LOCALIZED URBAN FLOODING WITH PONDING OF WATER. ALONG THE SOUTH SHORE...HIGHER DEWPOINT AIR COULD BECOME DELAYED ACROSS THE COLDER OCEAN WATERS. PRESENTLY OCEAN TEMPS HOVER AROUND THE MID 50S. IT IS WHEN DEWPOINTS RISE A FEW DEGREES ABOVE SUCH VALUES THAT THE LIKELIHOOD FOR COASTAL FOG DEVELOPMENT INCREASES. FEEL THE BEST CHANCES WILL BE TOWARDS THE MORNING HOURS AS DIURNAL COOLING MIXED WITH PROLONGED SOUTHERLY FETCH OF GREATER MOISTURE WILL YIELD DEWPOINTS IN THE 60S ALONG THE SOUTH SHORE. PATCHY FOG SUBSEQUENTLY MENTIONED. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... A MAJORITY OF THE FORECAST HINGES UPON THE EVOLUTION OF OVERNIGHT RAINS PARENT WITH THE SURFACE WARM FRONT...WHETHER CLEARING PROCEEDS TO ALLOW DESTABILIZATION OF THE LOCAL ENVIRONMENT AHEAD OF A WEAK TROUGH AXIS AND ATTENDANT MID-LEVEL ENERGY ANTICIPATED TO SWEEP THROUGH THE NORTHEASTERN CONUS DURING THE AFTERNOON INTO EVENING HOURS. THE MAIN KEY INGREDIENT TO THE POSSIBILITY OF CONVECTION IS SIMPLY INSTABILITY. SHEAR IS NO QUESTION. 0-6 KM BULK SHEAR VALUES CONTINUE TO BE ROBUST...WHILE HELICITY VALUES REMAIN NOTEWORTHY TOWARDS SUPPORTING ROTATING UPDRAFTS. OF SOME CONCERN IS WHETHER SURFACE WINDS CAN ENCOMPASS AN EASTERLY COMPONENT RESULTING IN A GREATER TURNING OF THE WIND WITHIN THE HODOGRAPH PROFILE. ECHOING THE SPC DAY 2 OUTLOOK...WHILE DAMAGING WINDS IS THE LIKELY THREAT WITH THE SHEAR PROFILE...A POTENTIAL BRIEF SPIN-UP IS NOT OUT OF THE QUESTION. BUT AGAIN THE POSSIBILITY HINGES ON SURFACE-BASED INSTABILITY BUILDING AND DESTABILIZATION OF THE BOUNDARY LAYER PROFILE. FEEL THE NORTH AND EAST FORECAST AREA WILL REMAIN STABLE...SOCKED IN BY CLOUDS AND COOLER TEMPERATURES. THUNDERSTORMS ARE NOT OUT OF THE QUESTION BUT THE CHANCES FOR SEVERE LOOK TO BE LOW. WILL SIMPLY GO WITH A MENTION OF THUNDERSTORMS. SOUTH AND WEST IT IS ENTIRELY PLAUSIBLE THAT CLOUDS COULD BREAK ALLOWING INSTABILITY TO BUILD UP TO 1000 TO 2000 J/KG OF CAPE... FORCED BY THE APPROACHING TROUGH AXIS AND MID-LEVEL ENERGY. WHILE THE BETTER CHANCES WILL BE ACROSS NY/PA...WITHIN THE CONNECTICUT VALLEY IT IS POSSIBLE INTO THE AFTERNOON TOWARDS THE EVENING HOURS TO SEE STORMS WITH SEVERE WEATHER THREATS OF DAMAGING WINDS...SMALL HAIL...AND THE POSSIBILITY OF A BRIEF TORNADO. GREATER CONFIDENCE LEANS TOWARDS DAMAGING WINDS AS THE FORECASTED WIND PROFILE IS MORE UNI-DIRECTIONAL...AND THE BOUNDARY LAYER EXHIBITS AN INVERTED-V PROFILE. FORECAST AMENDED ACCORDINGLY WITH THE PERCEIVED THREATS. DOWNPOURS WILL ALSO BE ANTICIPATED WITH THE VERY MOIST ATMOSPHERE POSSIBLY RESULTING IN URBAN FLOODING AND PONDING OF WATER. THE EVENING COMMUTE AROUND THE HARTFORD- SPRINGFIELD AREA MAY COME UNDER THREAT WITH POSSIBLE SEVERE WEATHER. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HIGHLIGHTS... * HEAT WAVE LIKELY FOR PORTIONS OF SNE THU THROUGH SAT * INCREASING THREAT OF SHOWERS/TSTMS SUN AFTN INTO MON * MORE SEASONABLE TEMPS EARLY NEXT WEEK OVERVIEW... MODELS IN GOOD AGREEMENT SIGNALING SUMMER HEAT AND HUMIDITY FOR THURSDAY THROUGH AT LEAST SATURDAY AS SE US RIDGE EXPANDS NORTHWARD ALONG THE EASTERN SEABOARD. IT APPEARS THE RIDGE WILL BEGIN TO BREAK DOWN SUNDAY INTO MONDAY AS GT LAKES TROF PUSHES EAST WITH INCREASING THREAT OF SHOWERS/TSTMS...THEN COOLER TEMPS FOR EARLY NEXT WEEK. THERE ARE DIFFERENCES BETWEEN GFS AND ECMWF REGARDING HOW QUICKLY SHOWERS EXIT THE REGION NEXT TUE. ECMWF IS MORE PROGRESSIVE AND DRIES IT OUT WHILE GFS AND ITS ENSEMBLE MEAN KEEPS THE TROF AXIS TO THE WEST WITH CONTINUED CHC SHOWERS/TSTMS. LOTS OF INHERENT UNCERTAINTY AT THIS TIME RANGE SO FORECAST WILL LIKELY UNDERGO CHANGES WITH TIME. THURSDAY THROUGH SATURDAY... SUMMERTIME HEAT AND HUMIDITY WILL BE THE THEME DURING THIS PERIOD AS MID LEVEL RIDGE BUILDS ACROSS THE REGION. 850 MB TEMPS INCREASE TO 16-17C THU AND NEAR 18C FRI AND SAT. EXPECT MAX TEMPS TO REACH UPPER 80S TO LOWER 90S DURING THIS PERIOD WITH SOME MID 90S POSSIBLE FRI/SAT IN THE INTERIOR VALLEYS. COOLER ALONG THE IMMEDIATE S COAST DUE TO SW COMPONENT TO THE WIND. A 3 DAY HEAT WAVE IS LIKELY FOR MANY INTERIOR LOCATIONS. ATMOSPHERE WILL DESTABILIZE EACH AFTERNOON SO CANT RULE OUT ISOLD TO WIDELY SCT CONVECTION...BUT LIMITED FORCING WILL KEEP AREAL COVERAGE QUITE LIMITED WITH DRY WEATHER MOST OF THE TIME. SUNDAY INTO MONDAY... AS RIDGE BEGINS TO BREAK DOWN...SLIGHTLY COOLER TEMPS ALOFT WILL INCREASE THREAT OF SHOWERS/TSTMS. MAIN THREAT SUNDAY WILL BE IN THE INTERIOR WITH FOCUS SHIFTING ACROSS REST OF SNE SUN NIGHT INTO MONDAY AS THE COLD FRONT MOVES INTO THE REGION. STILL QUITE WARM ON SUNDAY ALTHOUGH MORE CLOUDS AND SLIGHTLY COOLER 850 MB TEMPS WILL PROBABLY KEEP TEMPS IN THE 80S...COOLING TO THE 70S MONDAY. TUESDAY... LOTS OF UNCERTAINTY HERE WITH HOW QUICKLY THE FRONT CLEARS THE AREA. WE LEANED TOWARD MORE PROGRESSIVE ECMWF SOLUTION WITH MOSTLY DRY CONDITIONS...BUT A WETTER SCENARIO CANT BE RULED OUT. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /INTO WEDNESDAY NIGHT/...MODERATE CONFIDENCE. SOUTHERLY FLOW TO PROCEED INTO THE EVENING ERODING DAYTIME SEA- BREEZES. MVFR CIGS/VSBYS WILL BE POSSIBLE AS RAIN OVERSPREADS THE REGION TONIGHT INTO WEDNESDAY MORNING. IFR COASTAL FOG WILL BE AN ISSUE FOR THE SOUTH-COASTAL TERMINALS. INTO WEDNESDAY...SHRA/TSRA ANTICIPATED...BUT SPECIFICITY IS INDETERMINATE. CONFIDENCE OF A WIDESPREAD THREAT OF TEMPO MVFR/IFR IMPACTS...WITH A GREATER SEVERE THREAT ACROSS THE CONNECTICUT RIVER VALLEY. ENERGY AND TERMINAL IMPACTS CLEARING OUT INTO THURSDAY MORNING. KBOS TERMINAL...MODERATE CONFIDENCE. SEA-BREEZE SHOULD ERODE OUT INTO THE EVENING WITH WINDS BECOMING SOUTHERLY. KBDL TERMINAL...MODERATE CONFIDENCE. SEVERE WEATHER IS POSSIBLE DURING THE AFTERNOON INTO EVENING HOURS WEDNESDAY. OUTLOOK...THURSDAY THROUGH SUNDAY... MOSTLY VFR. ISOLATED AFTERNOON/EVENING TSTMS POSSIBLE WITH GREATEST THREAT SUN AFTERNOON IN THE INTERIOR. PATCHY LATE NIGHT/EARLY MORNING FOG POSSIBLE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /THROUGH WEDNESDAY NIGHT/... CONTINUED SOUTHERLY FETCH ACROSS THE WATERS THROUGH THE PERIOD WILL RESULT IN SEAS OF 5 TO 7 FEET ALONG THE OUTER WATERS. PERSISTED WITH A GENERIC SMALL CRAFT ADVISORY AS WINDS COULD GUST AS HIGH AS 25 KTS AT TIMES. RAIN AND COASTAL FOG IS EXPECTED TO BE AN ISSUE TOWARDS WEDNESDAY MORNING ALONG THE SOUTH AND SOUTHEAST WATERS. ZERO-VISIBILITIES ARE POSSIBLE WITH FOG...BUT FOR NOW A CONSERVATIVE FORECAST IS PRESENTED WITH VISIBILITIES DOWN TO 1-2 SM. THUNDERSTORMS WILL BE AN ISSUE DURING THE LATER HALF OF THE DAY WEDNESDAY INTO WEDNESDAY NIGHT. SOME OF THESE STORMS WILL HAVE THE POTENTIAL OF PRODUCING STRONG AND GUSTY GALE-FORCE WINDS. OUTLOOK...THURSDAY THROUGH SUNDAY... PERSISTENT SW FLOW MOSTLY BELOW SCA BUT WIND GUSTS COULD REACH 25 KT BY SUN. INCREASING SWELL WILL BUILD SEAS TO AROUND 5 FT LATE FRI INTO SAT...ESPECIALLY ON THE SOUTHERN EXPOSED WATERS...AND POSSIBLY REACHING 7 FT BY SUN. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 AM WEDNESDAY TO 8 AM EDT THURSDAY FOR ANZ235-237. SMALL CRAFT ADVISORY FROM 8 AM WEDNESDAY TO 8 AM EDT THURSDAY FOR ANZ250-254. SMALL CRAFT ADVISORY FROM 2 AM WEDNESDAY TO 8 AM EDT THURSDAY FOR ANZ255-256. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...KJC AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
345 PM EDT TUE MAY 28 2013 .SYNOPSIS... RAIN WILL OVERSPREAD THE REGION INTO THE OVERNIGHT HOURS INTO WEDNESDAY MORNING...WITH THE THUNDERSTORMS THEREAFTER INTO WEDNESDAY NIGHT. SUMMERTIME SIZZLE THEN VISITS FOR THURSDAY THROUGH SUNDAY ALONG WITH HIGHER HUMIDITY. A COLD FRONT SLIDES ACROSS THE REGION EARLY NEXT WEEK BRINGING MORE SEASONABLE TEMPERATURES. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 330 PM UPDATE... THE HRRR IS DOING THE BEST IN HANDLING THE PRECIPITATION SHIELD COLLOCATED WITH THE SURFACE WARM FRONT CENTERED AROUND THE NYC TRI-STATE REGION. FOLLOWING ACCORDINGLY...THE EXPECTATION IS FOR THE BATCH OF RAIN TO SLIDE SOUTH AND EAST UP AGAINST HIGH PRESSURE AND DRIER AIR ACROSS THE ATLANTIC. CHANCE TO LIKELY POPS SHOULD IMPACT MUCH OF CONNECTICUT NORTH INTO SPRINGFIELD AND WOCESTER MASSACHUSETTS INTO THE EVENING COMMUTE. RAIN LOOKS TO GET INTO RHODE ISLAND AROUND 8 PM. NO THUNDERSTORMS ARE ANTICIPATED WITH THE BATCH OF RAIN. RAIN AMOUNTS UPSTREAM ARE PRESENTLY LIGHT WITH HIGHEST VALUES WITHIN AN HOUR OF AROUND ONE- TENTH. TONIGHT... REINVIGORATION OF PRECIPITATION ALONG THE APPROACHING WARM FRONT WILL PROCEED INTO THE OVERNIGHT HOURS AS PRESENT ENERGY ACROSS MICHIGAN PROPAGATES WITH THE MEAN-FLOW ALONG THE NOSE OF A H925-85 JET. THE BULK OF THE ACTIVITY REMAINS NORTH ACROSS CENTRAL AND NORTHERN NEW ENGLAND UP INTO THE SAINT LAWRENCE VALLEY. MAINLY RAIN...THERE IS ALSO THE POSSIBILITY FOR THUNDERSTORMS PARENT WITH THE STRONGLY SHEARED PROFILE. BUT WITH LITTLE TO NO INSTABILITY...THUNDERSTORMS SHOULD BE VERY ISOLATED. JUST A RUMBLE OR TWO OF THUNDER. NO THREATS ARE PERCEIVED...BUT THERE COULD BE POCKETS OF HEAVIER RAIN THAT COULD LEAD TO LOCALIZED URBAN FLOODING WITH PONDING OF WATER. ALONG THE SOUTH SHORE...HIGHER DEWPOINT AIR COULD BECOME DELAYED ACROSS THE COLDER OCEAN WATERS. PRESENTLY OCEAN TEMPS HOVER AROUND THE MID 50S. IT IS WHEN DEWPOINTS RISE A FEW DEGREES ABOVE SUCH VALUES THAT THE LIKELIHOOD FOR COASTAL FOG DEVELOPMENT INCREASES. FEEL THE BEST CHANCES WILL BE TOWARDS THE MORNING HOURS AS DIURNAL COOLING MIXED WITH PROLONGED SOUTHERLY FETCH OF GREATER MOISTURE WILL YIELD DEWPOINTS IN THE 60S ALONG THE SOUTH SHORE. PATCHY FOG SUBSEQUENTLY MENTIONED. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... A MAJORITY OF THE FORECAST HINGES UPON THE EVOLUTION OF OVERNIGHT RAINS PARENT WITH THE SURFACE WARM FRONT...WHETHER CLEARING PROCEEDS TO ALLOW DESTABILIZATION OF THE LOCAL ENVIRONMENT AHEAD OF A WEAK TROUGH AXIS AND ATTENDANT MID-LEVEL ENERGY ANTICIPATED TO SWEEP THROUGH THE NORTHEASTERN CONUS DURING THE AFTERNOON INTO EVENING HOURS. THE MAIN KEY INGREDIENT TO THE POSSIBILITY OF CONVECTION IS SIMPLY INSTABILITY. SHEAR IS NO QUESTION. 0-6 KM BULK SHEAR VALUES CONTINUE TO BE ROBUST...WHILE HELICITY VALUES REMAIN NOTEWORTHY TOWARDS SUPPORTING ROTATING UPDRAFTS. OF SOME CONCERN IS WHETHER SURFACE WINDS CAN ENCOMPASS AN EASTERLY COMPONENT RESULTING IN A GREATER TURNING OF THE WIND WITHIN THE HODOGRAPH PROFILE. ECHOING THE SPC DAY 2 OUTLOOK...WHILE DAMAGING WINDS IS THE LIKELY THREAT WITH THE SHEAR PROFILE...A POTENTIAL BRIEF SPIN-UP IS NOT OUT OF THE QUESTION. BUT AGAIN THE POSSIBILITY HINGES ON SURFACE-BASED INSTABILITY BUILDING AND DESTABILIZATION OF THE BOUNDARY LAYER PROFILE. FEEL THE NORTH AND EAST FORECAST AREA WILL REMAIN STABLE...SOCKED IN BY CLOUDS AND COOLER TEMPERATURES. THUNDERSTORMS ARE NOT OUT OF THE QUESTION BUT THE CHANCES FOR SEVERE LOOK TO BE LOW. WILL SIMPLY GO WITH A MENTION OF THUNDERSTORMS. SOUTH AND WEST IT IS ENTIRELY PLAUSIBLE THAT CLOUDS COULD BREAK ALLOWING INSTABILITY TO BUILD UP TO 1000 TO 2000 J/KG OF CAPE... FORCED BY THE APPROACHING TROUGH AXIS AND MID-LEVEL ENERGY. WHILE THE BETTER CHANCES WILL BE ACROSS NY/PA...WITHIN THE CONNECTICUT VALLEY IT IS POSSIBLE INTO THE AFTERNOON TOWARDS THE EVENING HOURS TO SEE STORMS WITH SEVERE WEATHER THREATS OF DAMAGING WINDS...SMALL HAIL...AND THE POSSIBILITY OF A BRIEF TORNADO. GREATER CONFIDENCE LEANS TOWARDS DAMAGING WINDS AS THE FORECASTED WIND PROFILE IS MORE UNI-DIRECTIONAL...AND THE BOUNDARY LAYER EXHIBITS AN INVERTED-V PROFILE. FORECAST AMENDED ACCORDINGLY WITH THE PERCEIVED THREATS. DOWNPOURS WILL ALSO BE ANTICIPATED WITH THE VERY MOIST ATMOSPHERE POSSIBLY RESULTING IN URBAN FLOODING AND PONDING OF WATER. THE EVENING COMMUTE AROUND THE HARTFORD- SPRINGFIELD AREA MAY COME UNDER THREAT WITH POSSIBLE SEVERE WEATHER. && .LONG TERM /THURSDAY THROUGH TUESDAY/... BIG PICTURE... GULF OF ALASKA LOW DIGS OVER THE PAC NORTHWEST AND ROCKIES...WHICH INDUCES THE EASTERN UPPER RIDGE TO BUILD THROUGH SATURDAY. THIS LEAVES A CLEAR PATH FOR THE WARM HUMID AIR IN THE NATION/S MIDSECTION TO MOVE NORTHEAST INTO NEW ENGLAND. THE TROUGH OVER THE ROCKIES WILL MOVE INTO THE PLAINS OVER THE WEEKEND. MODELS AGREE ON THE UPPER RIDGE SHIFTING OVER THE OCEAN EARLY NEXT WEEK...MAKING ROOM FOR THE SHORTWAVE AND ITS SUPPORTING UPPER JET TO MOVE INTO THE NORTHEAST USA. MODEL PREFERENCES... UPPER CONTOUR FIELDS ARE SIMILAR FOR MOST OF THE PERIOD. THE ECMWF IS A LITTLE SHARPER WITH THE SHORTWAVE TROUGH EARLY NEXT WEEK. PREFER A BLEND OF HPC/GMOS AND ECMWF/GFS DATA. THE DAILIES... WEDNESDAY NIGHT... UPPER SHORTWAVE RACES ACROSS NEW ENGLAND PUSHING A WARM FRONT THROUGH THE REGION. ACTUALLY...THERE IS ALSO A COLD FRONT HIDDEN IN THE MODEL FIELDS...BUT ONE SO WEAK THAT ITS EFFECTS COULD BE OVERLOOKED. TEMPS ALOFT CONTINUE TO RISE OVERNIGHT. SUFFICIENT MOISTURE ALOFT AND TOTALS 45-50...SO SHOWERS/TSTMS ARE REASONABLE. TEMPS ARE A BLEND OF MOS. THURSDAY THROUGH SUNDAY... UPPER RIDGE BUILDS OVER THE REGION FOR THE LATE WEEK. TEMPS ALOFT UNDER THIS RIDGE ALSO BUILD WITH TEMPS AT THE TOP OF THE MIXED LAYER EQUIVALENT TO 17-18C AT 850 MB ESPECIALLY ON FRIDAY- SATURDAY. MEANWHILE THE PRESSURE GRADIENT SUPPORTS A SOUTHWEST WIND AND LOOKS TOO STRONG FOR AN EAST COAST SEABREEZE. THIS SUPPORTS MAX TEMPS 85-95 WITH THE WARMEST MAX TEMPS FRIDAY- SATURDAY. DEWPOINTS INCREASE INTO THE 60S WHICH IS SUPPORTED BY OBSERVED DEWPOINTS OVER THE SOUTHERN PLAINS AND LOWER MISS RIVER VALLEY...HIGHER VALUES ARE ONLY ALONG THE TEXAS GULF COAST. THIS WILL GIVE US A TASTE OF SUMMER HUMIDITY AND KEEP MIN TEMPS IN THE 60S. CONVECTION WILL BE A QUESTION THROUGH THE PERIOD. THE UPPER HIGH AND SUBSIDENT FLOW WILL WORK AGAINST ANY STORMS FORMING. BUT STABILITY PARAMETERS WILL REMAIN FAVORABLE...TOTALS HOLD AT 47 TO 50 PER ECMWF. SO CONVECTION IS POSSIBLE ANY OF THESE DAYS...BUT WITH LOW LIKELIHOOD THURSDAY AND FRIDAY. BEST CHANCE WILL BE SATURDAY AND SUNDAY IN THE CT VALLEY AND BERKSHIRE EAST SLOPE...BUT WITH A CHANCE LATER IN THE DAY FARTHER EAST. MONDAY... UPPER TROUGH FROM THE WEST COAST MOVES OVER NEW ENGLAND EARLY NEXT WEEK. THIS WILL PUSH A COLD FRONT THROUGH THE REGION. THE UPPER JET MOVING THROUGH THE TROUGH WILL PRESENT A RIGHT ENTRANCE REGION OVER OUR AREA WHICH WILL ENHANCE LIFT OVER THE HUMID UNSTABLE AIRMASS. SO SHOWERS/TSTMS ARE POSSIBLE. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /INTO WEDNESDAY NIGHT/...MODERATE CONFIDENCE. SOUTHERLY FLOW TO PROCEED INTO THE EVENING ERODING DAYTIME SEA- BREEZES. MVFR CIGS/VSBYS WILL BE POSSIBLE AS RAIN OVERSPREADS THE REGION TONIGHT INTO WEDNESDAY MORNING. IFR COASTAL FOG WILL BE AN ISSUE FOR THE SOUTH-COASTAL TERMINALS. INTO WEDNESDAY...SHRA/TSRA ANTICIPATED...BUT SPECIFICITY IS INDETERMINATE. CONFIDENCE OF A WIDESPREAD THREAT OF TEMPO MVFR/IFR IMPACTS...WITH A GREATER SEVERE THREAT ACROSS THE CONNECTICUT RIVER VALLEY. ENERGY AND TERMINAL IMPACTS CLEARING OUT INTO THURSDAY MORNING. KBOS TERMINAL...MODERATE CONFIDENCE. SEA-BREEZE SHOULD ERODE OUT INTO THE EVENING WITH WINDS BECOMING SOUTHERLY. KBDL TERMINAL...MODERATE CONFIDENCE. SEVERE WEATHER IS POSSIBLE DURING THE AFTERNOON INTO EVENING HOURS WEDNESDAY. OUTLOOK...THURSDAY THROUGH SATURDAY... THURSDAY THROUGH SATURDAY... MOSTLY VFR. ISOLATED TSTMS POSSIBLE THURSDAY ESPECIALLY VICINITY OF THE CT VALLEY. BETTER CHANCE OF BRIEF MVFR/IFR IN TSTMS ON SATURDAY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /THROUGH WEDNESDAY NIGHT/... CONTINUED SOUTHERLY FETCH ACROSS THE WATERS THROUGH THE PERIOD WILL RESULT IN SEAS OF 5 TO 7 FEET ALONG THE OUTER WATERS. PERSISTED WITH A GENERIC SMALL CRAFT ADVISORY AS WINDS COULD GUST AS HIGH AS 25 KTS AT TIMES. RAIN AND COASTAL FOG IS EXPECTED TO BE AN ISSUE TOWARDS WEDNESDAY MORNING ALONG THE SOUTH AND SOUTHEAST WATERS. ZERO-VISIBILITIES ARE POSSIBLE WITH FOG...BUT FOR NOW A CONSERVATIVE FORECAST IS PRESENTED WITH VISIBILITIES DOWN TO 1-2 SM. THUNDERSTORMS WILL BE AN ISSUE DURING THE LATER HALF OF THE DAY WEDNESDAY INTO WEDNESDAY NIGHT. SOME OF THESE STORMS WILL HAVE THE POTENTIAL OF PRODUCING STRONG AND GUSTY GALE-FORCE WINDS. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEST TO SOUTHWEST WIND REMAINS BELOW 25 KNOTS THROUGH THE PERIOD. BUT THE WIND WILL BUILD SEAS OF 5-7 FEET ESPECIALLY ON THE SOUTHERN EXPOSED WATERS. A LENGTHY SMALL CRAFT ADVISORY WILL BE NEEDED FOR THESE SEAS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 AM WEDNESDAY TO 8 AM EDT THURSDAY FOR ANZ235-237. SMALL CRAFT ADVISORY FROM 8 AM WEDNESDAY TO 8 AM EDT THURSDAY FOR ANZ250-254. SMALL CRAFT ADVISORY FROM 2 AM WEDNESDAY TO 8 AM EDT THURSDAY FOR ANZ255-256. && $$ SYNOPSIS...DOODY/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...WTB AVIATION...WTB/SIPPRELL MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
323 PM EDT TUE MAY 28 2013 .SYNOPSIS... RAIN WILL OVERSPREAD THE REGION INTO THE OVERNIGHT HOURS CONTINUING INTO WEDNESDAY MORNING...WITH THE THUNDERSTORMS THEREAFTER INTO WEDNESDAY NIGHT. SUMMERTIME SIZZLE THEN VISITS FOR THURSDAY THROUGH SUNDAY ALONG WITH HIGHER HUMIDITY. A COLD FRONT SLIDES ACROSS THE REGION EARLY NEXT WEEK BRINGING MORE SEASONABLE TEMPERATURES. && .NEAR TERM /THROUGH TONIGHT/... 330 PM UPDATE... THE HRRR IS DOING THE BEST IN HANDLING THE PRECIPITATION SHIELD COLLOCATED WITH THE SURFACE WARM FRONT CENTERED AROUND THE NYC TRI-STATE REGION. FOLLOWING ACCORDINGLY...THE EXPECTATION IS FOR THE BATCH OF RAIN TO SLIDE SOUTH AND EAST UP AGAINST HIGH PRESSURE AND DRIER AIR ACROSS THE ATLANTIC. CHANCE TO LIKELY POPS SHOULD IMPACT MUCH OF CONNECTICUT NORTH INTO SPRINGFIELD AND WOCESTER MASSACHUSETTS INTO THE EVENING COMMUTE. RAIN LOOKS TO GET INTO RHODE ISLAND AROUND 8 PM. NO THUNDERSTORMS ARE ANTICIPATED WITH THE BATCH OF RAIN. RAIN AMOUNTS UPSTREAM ARE PRESENTLY LIGHT WITH HIGHEST VALUES WITHIN AN HOUR OF AROUND ONE- TENTH. TONIGHT... REINVIGORATION OF PRECIPITATION ALONG THE APPROACHING WARM FRONT WILL PROCEED INTO THE OVERNIGHT HOURS AS PRESENT ENERGY ACROSS MICHIGAN PROPAGATES WITH THE MEAN-FLOW ALONG THE NOSE OF A H925-85 JET. THE BULK OF THE ACTIVITY REMAINS NORTH ACROSS CENTRAL AND NORTHERN NEW ENGLAND UP INTO THE SAINT LAWRENCE VALLEY. MAINLY RAIN...THERE IS ALSO THE POSSIBILITY FOR THUNDERSTORMS PARENT WITH THE STRONGLY SHEARED PROFILE. BUT WITH LITTLE TO NO INSTABILITY...THUNDERSTORMS SHOULD BE VERY ISOLATED. JUST A RUMBLE OR TWO OF THUNDER. NO THREATS ARE PERCEIVED...BUT THERE COULD BE POCKETS OF HEAVIER RAIN THAT COULD LEAD TO LOCALIZED URBAN FLOODING WITH PONDING OF WATER. ALONG THE SOUTH SHORE...HIGHER DEWPOINT AIR COULD BECOME DELAYED ACROSS THE COLDER OCEAN WATERS. PRESENTLY OCEAN TEMPS HOVER AROUND THE MID 50S. IT IS WHEN DEWPOINTS RISE A FEW DEGREES ABOVE SUCH VALUES THAT THE LIKELIHOOD FOR COASTAL FOG DEVELOPMENT INCREASES. FEEL THE BEST CHANCES WILL BE TOWARDS THE MORNING HOURS AS DIURNAL COOLING MIXED WITH PROLONGED SOUTHERLY FETCH OF GREATER MOISTURE WILL YIELD DEWPOINTS IN THE 60S ALONG THE SOUTH SHORE. PATCHY FOG SUBSEQUENTLY MENTIONED. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... A MAJORITY OF THE FORECAST HINGES UPON THE EVOLUTION OF OVERNIGHT RAINS PARENT WITH THE SURFACE WARM FRONT...WHETHER CLEARING PROCEEDS TO ALLOW DESTABILIZATION OF THE LOCAL ENVIRONMENT AHEAD OF A WEAK TROUGH AXIS AND ATTENDANT MID-LEVEL ENERGY ANTICIPATED TO SWEEP THROUGH THE NORTHEASTERN CONUS DURING THE AFTERNOON INTO EVENING HOURS. THE MAIN KEY INGREDIENT TO THE POSSIBILITY OF CONVECTION IS SIMPLY INSTABILITY. SHEAR IS NO QUESTION. 0-6 KM BULK SHEAR VALUES CONTINUE TO BE ROBUST...WHILE HELICITY VALUES REMAIN NOTEWORTHY TOWARDS SUPPORTING ROTATING UPDRAFTS. OF SOME CONCERN IS WHETHER SURFACE WINDS CAN ENCOMPASS AN EASTERLY COMPONENT RESULTING IN A GREATER TURNING OF THE WIND WITHIN THE HODOGRAPH PROFILE. ECHOING THE SPC DAY 2 OUTLOOK...WHILE DAMAGING WINDS IS THE LIKELY THREAT WITH THE SHEAR PROFILE...A POTENTIAL BRIEF SPIN-UP IS NOT OUT OF THE QUESTION. BUT AGAIN THE POSSIBILITY HINGES ON SURFACE-BASED INSTABILITY BUILDING AND DESTABILIZATION OF THE BOUNDARY LAYER PROFILE. FEEL THE NORTH AND EAST FORECAST AREA WILL REMAIN STABLE...SOCKED IN BY CLOUDS AND COOLER TEMPERATURES. THUNDERSTORMS ARE NOT OUT OF THE QUESTION BUT THE CHANCES FOR SEVERE LOOK TO BE LOW. WILL SIMPLY GO WITH A MENTION OF THUNDERSTORMS. SOUTH AND WEST IT IS ENTIRELY PLAUSIBLE THAT CLOUDS COULD BREAK ALLOWING INSTABILITY TO BUILD UP TO 1000 TO 2000 J/KG OF CAPE... FORCED BY THE APPROACHING TROUGH AXIS AND MID-LEVEL ENERGY. WHILE THE BETTER CHANCES WILL BE ACROSS NY/PA...WITHIN THE CONNECTICUT VALLEY IT IS POSSIBLE INTO THE AFTERNOON TOWARDS THE EVENING HOURS TO SEE STORMS WITH SEVERE WEATHER THREATS OF DAMAGING WINDS...SMALL HAIL...AND THE POSSIBILITY OF A BRIEF TORNADO. GREATER CONFIDENCE LEANS TOWARDS DAMAGING WINDS AS THE FORECASTED WIND PROFILE IS MORE UNI-DIRECTIONAL...AND THE BOUNDARY LAYER EXHIBITS AN INVERTED-V PROFILE. DOWNPOURS WILL ALSO BE ANTICIPATED WITH THE VERY MOIST ATMOSPHERE POSSIBLY RESULTING IN URBAN FLOODING AND PONDING OF WATER. THE EVENING COMMUTE AROUND THE HARTFORD-SPRINGFIELD AREA MAY COME UNDER THREAT WITH POSSIBLE SEVERE WEATHER. && .LONG TERM /THURSDAY THROUGH TUESDAY/... BIG PICTURE... GULF OF ALASKA LOW DIGS OVER THE PAC NORTHWEST AND ROCKIES...WHICH INDUCES THE EASTERN UPPER RIDGE TO BUILD THROUGH SATURDAY. THIS LEAVES A CLEAR PATH FOR THE WARM HUMID AIR IN THE NATION/S MIDSECTION TO MOVE NORTHEAST INTO NEW ENGLAND. THE TROUGH OVER THE ROCKIES WILL MOVE INTO THE PLAINS OVER THE WEEKEND. MODELS AGREE ON THE UPPER RIDGE SHIFTING OVER THE OCEAN EARLY NEXT WEEK...MAKING ROOM FOR THE SHORTWAVE AND ITS SUPPORTING UPPER JET TO MOVE INTO THE NORTHEAST USA. MODEL PREFERENCES... UPPER CONTOUR FIELDS ARE SIMILAR FOR MOST OF THE PERIOD. THE ECMWF IS A LITTLE SHARPER WITH THE SHORTWAVE TROUGH EARLY NEXT WEEK. PREFER A BLEND OF HPC/GMOS AND ECMWF/GFS DATA. THE DAILIES... WEDNESDAY NIGHT... UPPER SHORTWAVE RACES ACROSS NEW ENGLAND PUSHING A WARM FRONT THROUGH THE REGION. ACTUALLY...THERE IS ALSO A COLD FRONT HIDDEN IN THE MODEL FIELDS...BUT ONE SO WEAK THAT ITS EFFECTS COULD BE OVERLOOKED. TEMPS ALOFT CONTINUE TO RISE OVERNIGHT. SUFFICIENT MOISTURE ALOFT AND TOTALS 45-50...SO SHOWERS/TSTMS ARE REASONABLE. TEMPS ARE A BLEND OF MOS. THURSDAY THROUGH SUNDAY... UPPER RIDGE BUILDS OVER THE REGION FOR THE LATE WEEK. TEMPS ALOFT UNDER THIS RIDGE ALSO BUILD WITH TEMPS AT THE TOP OF THE MIXED LAYER EQUIVALENT TO 17-18C AT 850 MB ESPECIALLY ON FRIDAY- SATURDAY. MEANWHILE THE PRESSURE GRADIENT SUPPORTS A SOUTHWEST WIND AND LOOKS TOO STRONG FOR AN EAST COAST SEABREEZE. THIS SUPPORTS MAX TEMPS 85-95 WITH THE WARMEST MAX TEMPS FRIDAY- SATURDAY. DEWPOINTS INCREASE INTO THE 60S WHICH IS SUPPORTED BY OBSERVED DEWPOINTS OVER THE SOUTHERN PLAINS AND LOWER MISS RIVER VALLEY...HIGHER VALUES ARE ONLY ALONG THE TEXAS GULF COAST. THIS WILL GIVE US A TASTE OF SUMMER HUMIDITY AND KEEP MIN TEMPS IN THE 60S. CONVECTION WILL BE A QUESTION THROUGH THE PERIOD. THE UPPER HIGH AND SUBSIDENT FLOW WILL WORK AGAINST ANY STORMS FORMING. BUT STABILITY PARAMETERS WILL REMAIN FAVORABLE...TOTALS HOLD AT 47 TO 50 PER ECMWF. SO CONVECTION IS POSSIBLE ANY OF THESE DAYS...BUT WITH LOW LIKELIHOOD THURSDAY AND FRIDAY. BEST CHANCE WILL BE SATURDAY AND SUNDAY IN THE CT VALLEY AND BERKSHIRE EAST SLOPE...BUT WITH A CHANCE LATER IN THE DAY FARTHER EAST. MONDAY... UPPER TROUGH FROM THE WEST COAST MOVES OVER NEW ENGLAND EARLY NEXT WEEK. THIS WILL PUSH A COLD FRONT THROUGH THE REGION. THE UPPER JET MOVING THROUGH THE TROUGH WILL PRESENT A RIGHT ENTRANCE REGION OVER OUR AREA WHICH WILL ENHANCE LIFT OVER THE HUMID UNSTABLE AIRMASS. SO SHOWERS/TSTMS ARE POSSIBLE. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /INTO WEDNESDAY NIGHT/...MODERATE CONFIDENCE. SOUTHERLY FLOW TO PROCEED INTO THE EVENING ERODING DAYTIME SEA- BREEZES. MVFR CIGS/VSBYS WILL BE POSSIBLE AS RAIN OVERSPREADS THE REGION TONIGHT INTO WEDNESDAY MORNING. IFR COASTAL FOG WILL BE AN ISSUE FOR THE SOUTH-COASTAL TERMINALS. INTO WEDNESDAY...SHRA/TSRA ANTICIPATED...BUT SPECIFICITY IS INDETERMINATE. CONFIDENCE OF A WIDESPREAD THREAT OF TEMPO MVFR/IFR IMPACTS...WITH A GREATER SEVERE THREAT ACROSS THE CONNECTICUT RIVER VALLEY. ENERGY AND TERMINAL IMPACTS CLEARING OUT INTO THURSDAY MORNING. KBOS TERMINAL...MODERATE CONFIDENCE. SEA-BREEZE SHOULD ERODE OUT INTO THE EVENING WITH WINDS BECOMING SOUTHERLY. KBDL TERMINAL...MODERATE CONFIDENCE. SEVERE WEATHER IS POSSIBLE DURING THE AFTERNOON INTO EVENING HOURS WEDNESDAY. OUTLOOK...THURSDAY THROUGH SATURDAY... THURSDAY THROUGH SATURDAY... MOSTLY VFR. ISOLATED TSTMS POSSIBLE THURSDAY ESPECIALLY VICINITY OF THE CT VALLEY. BETTER CHANCE OF BRIEF MVFR/IFR IN TSTMS ON SATURDAY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH THE PERIOD. MAINLY QUIET BOATING WEATHER CONTINUES TODAY. HOWEVER TONIGHT... EXPECT A WARM FRONT TO ALLOW SOUTHERLY WINDS TO GRADUALLY INCREASE ALONG WITH SEAS INTO THE DAY WED. SEAS WILL LIKELY REACH 5-6 FT EARLY WED MORNING FIRST ON SRN WATERS...THEN ERN WATERS DURING THE DAY WED. WIND GUSTS NEAR 25 KT POSSIBLE AT TIMES WED AS WELL. THEREFORE...WILL ISSUE SMALL CRAFT ADVISORIES FOR EARLY MORNING WED INTO THE DAY WED...PRIMARILY ON OCEAN WATERS. OTHERWISE...SOME SHOWERS AND FOG MAY LEAD TO REDUCTION IN VISIBILITY OVERNIGHT TONIGHT. ON WED...THERE IS A THREAT FOR THUNDERSTORMS...WHICH MAY HAVE SOME STRONG WINDS AND SMALL HAIL PARTICULARLY DURING THE AFTERNOON HOURS. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEST TO SOUTHWEST WIND REMAINS BELOW 25 KNOTS THROUGH THE PERIOD. BUT THE WIND WILL BUILD SEAS OF 5-7 FEET ESPECIALLY ON THE SOUTHERN EXPOSED WATERS. A LENGTHY SMALL CRAFT ADVISORY WILL BE NEEDED FOR THESE SEAS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 8 PM EDT WEDNESDAY FOR ANZ235-237-255-256. SMALL CRAFT ADVISORY FROM 8 AM TO 8 PM EDT WEDNESDAY FOR ANZ250-254. && $$ SYNOPSIS...WTB/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...WTB AVIATION...WTB/SIPPRELL MARINE...WTB/DOODY
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1019 AM EDT TUE MAY 28 2013 .SYNOPSIS... MAINLY DRY WEATHER TODAY AS HIGH PRESSURE EXITS TO THE EAST. A WARM FRONT WILL LIFT THROUGH THE AREA TONIGHT BRINGING SOME SHOWERS OVERNIGHT...AND WITH THUNDERSTORMS POSSIBLE WEDNESDAY. SUMMERTIME SIZZLE THEN VISITS FOR THURSDAY THROUGH SUNDAY ALONG WITH HIGHER HUMIDITY. A COLD FRONT SLIDES ACROSS THE REGION EARLY NEXT WEEK BRINGING MORE SEASONABLE TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1030 AM UPDATE... DID NOT GO AHEAD WITH ANY CHANGES TO THE NEAR-TERM FORECAST. WILL AWAIT 28.12Z FORECAST GUIDANCE BEFORE MAKING ANY CHANGES. INITIAL GLANCE...PRESENT PRECIPITATION SHIELD ACROSS NY/PA/NJ IS MOVING SLIGHTLY FASTER THAN 0Z/6Z FORECAST GUIDANCE CURRENTLY PROJECTS. IN ADDITION...HIGH PRESSURE REMAINS IN CONTROL OF THE REGIONS WEATHER. THE EXPECTATION IS FOR THE PRECIPITATION SHIELD TO MOVE INTO THE REGION SLIGHTLY FASTER...BUT ERODE WITH THE COMBINATION OF SUBSIDENCE AND MID-LAYER DRIER AIR ASSOCIATED WITH THE HIGH /SEE THE 28.12Z CHATHAM SOUNDING/. LESSER CONFIDENCE ON THE THUNDER RISK...AND WILL CONTINUE TO KEEP IT OUT OF THE FORECAST FOR TODAY. 28.12Z HRRR IS THE BEST MODEL BY FAR. THEREAFTER...THE FORECAST PATTERN IS SUCCINCT WITH THE MCS REMNANTS MOVING EAST-NORTHEAST WITH THE 0-6 KM MEAN WIND THROUGH NORTHERN NEW ENGLAND AND THE SAINT LAWRENCE RIVER VALLEY WITH THE BETTER DYNAMICS ALONG THE SURFACE WARM FRONT. THE LATEST 28.12Z NAM HAS THE HEAVIER PRECIPITATION SLIGHTLY SOUTH THAN ITS PREDECESSOR...WITH ALL OTHER GUIDANCE REMAINING NORTH. WHILE AWAITING LATER GUIDANCE...FEELING IS FOR BETTER PRECIPITATION CHANCES NORTH AND WEST INTO THE EVENING...WHILE SOUTH AND EAST WILL SUCCUMB TO SUBSIDENCE AND DRIER AIR. PREVIOUS DISCUSSION... SFC WARM FRONT APPROACHES FROM THE NW. HOWEVER...FAIRLY DRY SOUNDING PROFILE UNDER SUBSIDENCE INVERSION SUGGESTS MOSTLY DRY WX CONTINUES INTO THE DAY THROUGH THE DAY TODAY. WILL NEED TO WATCH UPSTREAM POTENTIAL CONVECTIVE DEVELOPMENT AS THIS WILL HAVE TWO EFFECTS...MAINLY ON THE CONVECTIVE AND RAIN THREAT OVERNIGHT AND ON HOW QUICKLY SKIES BECOME COMPLETELY OVC FROM ANY CI BLOWOFF. OTHERWISE...A FAIRLY PLEASANT DAY WITH TEMPS REACHING INTO THE LOW TO MID 70S ONCE AGAIN WITH ONLY SLOWLY INCREASING SFC DEWPOINTS. SEA BREEZES ARE LIKELY TO KEEP NEAR SHORE LOCATIONS COOLER AND IN THE 60S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT... ON THE SYNOPTIC SCALE...SFC WARM FRONT APPROACHES FROM THE SW AS UPPER LVL SHORTWAVE MOVES ACROSS THE AREA FROM NY. SOUNDINGS SUGGEST THAT THE MID LVL WARM FRONT MOVES WELL AHEAD OF THE SFC WARM FRONT...ALLOWING H85 TEMPS TO INCREASE QUICKLY OVERNIGHT AND PRODUCING A STABLE /AND INVERTED/ NEAR SFC PROFILE. GUIDANCE IS NOW CONVERGING ON THE TIMING OF THE SFC FRONT...SUGGESTING IT IS ONLY JUST AT THE SW BOX CWA DOORSTEP BY 12Z. THEREFORE...SOUNDINGS ARE QUITE STABLE THROUGHOUT /ESPECIALLY NEAR THE SFC/ WITH BEST UPPER LVL COOLING AND SFC WARMING HOLDING OFF UNTIL DAYBREAK. WILL NEED TO AT LEAST WATCH UPSTREAM CONVECTIVE DEVELOPMENT THROUGH THE AFTERNOON AS SOME GUIDANCE HAS PUSHED THE REMNANTS OF AN MCC THROUGH THE REGION DURING THE OVERNIGHT HOURS. HOWEVER...RECENT GUIDANCE TRENDS LOOKS FAVORABLE...SUGGESTING ANY REMNANT CONVECTION WOULD BE WEAKENING RAPIDLY AS IT APPROACHES SRN NEW ENGLAND. STILL IS AT LEAST SOME /NEAR 30-40 KT/ 0-6KM BULK SHEAR NOTED AHEAD OF THE FRONT...BUT WITH LITTLE INSTABILITY THROUGH ABOUT H5 THERE WILL BE LITTLE TO WORK WITH. PRIMARY THREAT DURING THE OVERNIGHT HOURS IS AN ISOLATED RUMBLE OF THUNDER AND BRIEF HEAVY DOWNPOUR AS ANY REMNANT CONVECTION MOVES E AS PWAT VALUES INCREASE TO 1.5 INCHES. WILL AT LEAST NEED TO MONITOR ANY SHIFT IN WARM FRONT POSITIONING HOWEVER...BECAUSE A SLIGHT ADJUSTMENT COULD ALLOW CONVECTION TO HOLD UNTIL REACHING SRN NEW ENGLAND...BUT FOR NOW BEST INSTABILITY AND STEERING FLOW LOOKS TO STAY SW THROUGH 12Z. WED... WITH DIURNAL TEMP INCREASE AND HELP FROM SUNRISE...EXPECT THAT SFC WARM FRONT WILL GRADUALLY LIFT THROUGH THE AREA DURING THE DAY. THIS WILL ALLOW INCREASING SFC TEMPS AND DWPTS /WHICH REACH INTO THE 60S BY AFTERNOON/. AT THE SAME TIME...SECONDARY SHORTWAVE IS EXPECTED TO PUSH THROUGH THE AREA DURING THE AFTERNOON WITH SOME DECREASE IN H5 TEMPS. GIVEN THESE FACTORS...CONTINUE TO NOTE DECREASING STABILITY THROUGH THE DAY WITH THE POTENTIAL FOR SB CAPE VALUES APPROACHING 1000-1500 J/KG BY THE AFTERNOON. SHOULD THERE BE A FEW BREAKS OF SUN IN THE WARM SECTOR AS THE FRONT LIFTS N...THIS COULD EASILY APPROACH 2000+ J/KG. WITH UPPER LVL WAVE AND SFC BOUNDARY IN PLACE...FEEL THERE WILL BE ENOUGH OF A FOCUS FOR LIFT TO REALIZE THIS INSTABILITY THROUGH THE DAY. BULK SHEAR VALUES REACH 30-40 KT DURING THE DAY WITH A HODOGRAPH SUGGESTING NEARLY UNIFORM SHEAR DURING THE AFTERNOON. COMBINE THIS WITH A DECENT INVERTED-V PROFILE IN SOUNDINGS AND THE PRIMARY THREAT LOOKS TO BE STRONG-GUSTY WINDS WITH ANY POTENTIALLY SEVERE THUNDERSTORMS. LOW TO MID LVL HELICITY VALUES ARE NOT EXTREME HERE...BUT DO AT LEAST SUGGEST SOME ROTATING UPDRAFTS POSSIBLE. NORMALIZED CAPE VALUES ARE LOW...SO WITH ONLY MODEST ROTATING UPDRAFTS...HAIL THREAT LOOKS TO BE LOWER THAN STRONG WIND THREAT. IN ANY STORMS...BRIEF HEAVY RAIN POSSIBLE AS WELL WITH PWAT VALUES IN 1.5+ INCHES...BUT STORMS SHOULD MOVE FAIRLY WELL GIVEN THE UNI-DIRECTIONAL WIND PROFILE. THE BEST THREAT FOR SEVERE STORMS LOOK TO BE TOWARD THE N AND W OF THE AREA...CLOSER TO THE WARM FRONT FOR LIFT TO THE N...AND DEEPER IN THE WARM SECTOR AS ONE HEADS W. THEREFORE...BEST THREAT FOR SEVERE LOOKS TO BE IN WRN MA/CT AND SW NH THROUGH THE AFTERNOON. THIS COINCIDES WITH 28/06Z CATEGORICAL SPC OUTLOOK UPDATE WITH SLIGHT RISK IN THIS REGION. WILL CONTINUE WITH PREVIOUS SHIFTS THINKING...ADDING ENHANCED WORDING FOR GUSTY WINDS AND SMALL HAIL WITH THIS UPDATE. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... BIG PICTURE... GULF OF ALASKA LOW DIGS OVER THE PAC NORTHWEST AND ROCKIES...WHICH INDUCES THE EASTERN UPPER RIDGE TO BUILD THROUGH SATURDAY. THIS LEAVES A CLEAR PATH FOR THE WARM HUMID AIR IN THE NATION/S MIDSECTION TO MOVE NORTHEAST INTO NEW ENGLAND. THE TROUGH OVER THE ROCKIES WILL MOVE INTO THE PLAINS OVER THE WEEKEND. MODELS AGREE ON THE UPPER RIDGE SHIFTING OVER THE OCEAN EARLY NEXT WEEK...MAKING ROOM FOR THE SHORTWAVE AND ITS SUPPORTING UPPER JET TO MOVE INTO THE NORTHEAST USA. MODEL PREFERENCES... UPPER CONTOUR FIELDS ARE SIMILAR FOR MOST OF THE PERIOD. THE ECMWF IS A LITTLE SHARPER WITH THE SHORTWAVE TROUGH EARLY NEXT WEEK. PREFER A BLEND OF HPC/GMOS AND ECMWF/GFS DATA. THE DAILIES... WEDNESDAY NIGHT... UPPER SHORTWAVE RACES ACROSS NEW ENGLAND PUSHING A WARM FRONT THROUGH THE REGION. ACTUALLY...THERE IS ALSO A COLD FRONT HIDDEN IN THE MODEL FIELDS...BUT ONE SO WEAK THAT ITS EFFECTS COULD BE OVERLOOKED. TEMPS ALOFT CONTINUE TO RISE OVERNIGHT. SUFFICIENT MOISTURE ALOFT AND TOTALS 45-50...SO SHOWERS/TSTMS ARE REASONABLE. TEMPS ARE A BLEND OF MOS. THURSDAY THROUGH SUNDAY... UPPER RIDGE BUILDS OVER THE REGION FOR THE LATE WEEK. TEMPS ALOFT UNDER THIS RIDGE ALSO BUILD WITH TEMPS AT THE TOP OF THE MIXED LAYER EQUIVALENT TO 17-18C AT 850 MB ESPECIALLY ON FRIDAY- SATURDAY. MEANWHILE THE PRESSURE GRADIENT SUPPORTS A SOUTHWEST WIND AND LOOKS TOO STRONG FOR AN EAST COAST SEABREEZE. THIS SUPPORTS MAX TEMPS 85-95 WITH THE WARMEST MAX TEMPS FRIDAY- SATURDAY. DEWPOINTS INCREASE INTO THE 60S WHICH IS SUPPORTED BY OBSERVED DEWPOINTS OVER THE SOUTHERN PLAINS AND LOWER MISS RIVER VALLEY...HIGHER VALUES ARE ONLY ALONG THE TEXAS GULF COAST. THIS WILL GIVE US A TASTE OF SUMMER HUMIDITY AND KEEP MIN TEMPS IN THE 60S. CONVECTION WILL BE A QUESTION THROUGH THE PERIOD. THE UPPER HIGH AND SUBSIDENT FLOW WILL WORK AGAINST ANY STORMS FORMING. BUT STABILITY PARAMETERS WILL REMAIN FAVORABLE...TOTALS HOLD AT 47 TO 50 PER ECMWF. SO CONVECTION IS POSSIBLE ANY OF THESE DAYS...BUT WITH LOW LIKELIHOOD THURSDAY AND FRIDAY. BEST CHANCE WILL BE SATURDAY AND SUNDAY IN THE CT VALLEY AND BERKSHIRE EAST SLOPE...BUT WITH A CHANCE LATER IN THE DAY FARTHER EAST. MONDAY... UPPER TROUGH FROM THE WEST COAST MOVES OVER NEW ENGLAND EARLY NEXT WEEK. THIS WILL PUSH A COLD FRONT THROUGH THE REGION. THE UPPER JET MOVING THROUGH THE TROUGH WILL PRESENT A RIGHT ENTRANCE REGION OVER OUR AREA WHICH WILL ENHANCE LIFT OVER THE HUMID UNSTABLE AIRMASS. SO SHOWERS/TSTMS ARE POSSIBLE. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW THROUGH WED...HIGH CONFIDENCE THROUGH TODAY...WITH LOWER CONFIDENCE TONIGHT INTO WED. VFR UNDER HIGH PRES CONTINUES THROUGH THE DAY TOMORROW. HOWEVER...PERIODS OF MVFR/IFR OCCUR THIS EVENING...INTO THE OVERNIGHT HOURS FROM SW TO NE AS A WARM FRONT APPROACHES. LOW CONFIDENCE IN THUNDER FOR TONIGHT. DURING THE DAY WED...SOME SHOWERS AND THUNDERSTORMS ARE POSSIBLE...ESPECIALLY NORTH OF THE MA PIKE. SEA BREEZES LIKELY TODAY. KBOS TERMINAL...HIGH CONFIDENCE. SEA-BREEZE AROUND 15Z TUESDAY. ONSET OF RAIN LATE WED EVENING. KBDL TERMINAL...HIGH CONFIDENCE. ONSET OF RAIN INTO THE EVENING HOURS. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEDNESDAY NIGHT... SHOWERS/TSTMS WITH PERIODS OF IFR/MVFR CIGS AND VSBYS. POTENTIAL FOR IFR/LIFR CIGS/VSBYS IN FOG LATE AT NIGHT. THURSDAY THROUGH SATURDAY... MOSTLY VFR. ISOLATED TSTMS POSSIBLE THURSDAY ESPECIALLY VICINITY OF THE CT VALLEY. BETTER CHANCE OF BRIEF MVFR/IFR IN TSTMS ON SATURDAY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH THE PERIOD. MAINLY QUIET BOATING WEATHER CONTINUES TODAY. HOWEVER TONIGHT... EXPECT A WARM FRONT TO ALLOW SOUTHERLY WINDS TO GRADUALLY INCREASE ALONG WITH SEAS INTO THE DAY WED. SEAS WILL LIKELY REACH 5-6 FT EARLY WED MORNING FIRST ON SRN WATERS...THEN ERN WATERS DURING THE DAY WED. WIND GUSTS NEAR 25 KT POSSIBLE AT TIMES WED AS WELL. THEREFORE...WILL ISSUE SMALL CRAFT ADVISORIES FOR EARLY MORNING WED INTO THE DAY WED...PRIMARILY ON OCEAN WATERS. OTHERWISE...SOME SHOWERS AND FOG MAY LEAD TO REDUCTION IN VISIBILITY OVERNIGHT TONIGHT. ON WED...THERE IS A THREAT FOR THUNDERSTORMS...WHICH MAY HAVE SOME STRONG WINDS AND SMALL HAIL PARTICULARLY DURING THE AFTERNOON HOURS. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEST TO SOUTHWEST WIND REMAINS BELOW 25 KNOTS THROUGH THE PERIOD. BUT THE WIND WILL BUILD SEAS OF 5-7 FEET ESPECIALLY ON THE SOUTHERN EXPOSED WATERS. A LENGTHY SMALL CRAFT ADVISORY WILL BE NEEDED FOR THESE SEAS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 8 PM EDT WEDNESDAY FOR ANZ235-237-255-256. SMALL CRAFT ADVISORY FROM 8 AM TO 8 PM EDT WEDNESDAY FOR ANZ250-254. && $$ SYNOPSIS...WTB/DOODY NEAR TERM...SIPPRELL SHORT TERM...DOODY LONG TERM...WTB AVIATION...WTB/DOODY MARINE...WTB/DOODY
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
621 AM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL LIFT ACROSS THE AREA THIS AFTERNOON AND EARLY TONIGHT. HIGH PRESSURE OFF THE EAST COAST WILL RIDGE BACK ACROSS OUR AREA FOR THE MIDDLE AND LATE PARTS OF THIS WEEK. LOW PRESSURE WILL MOVE NORTH OF THE REGION SATURDAY AND SUNDAY AND SEND A COLD FRONT ACROSS THE AREA EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 610 AM ESTF PRODUCTS UPDATE: RAISED POPS A BIT...EXPANDED AREA FOR POTENTIALLY BRIEFLY HEAVY SHOWERS INTO SE PA AND S CENTRAL NJ AND COOLED TEMPS SEVERAL DEGREES IN NNJ. TODAY...IT LOOKS AS THOUGH THE CONVECTIVE MODELS FROM NCEP HAVE AGAIN PREVAILED WHEN COMPARED TO YDYS 00Z/27 CYCLE OF THE RGEM/GGEM/ECMWF/UKMET. A DECENT SLUG OF SHOWERS IS FORECAST TODAY WITH A N/S BAND OF BRIEFLY MODERATE TO HEAVY RAIN SWEEPING EWD WITHIN THE GROWING AREA OF RAIN ACROSS PA/NJ. THE 00Z/28 SPC WRF IS TO MY OVERALL LIKING AND IS MATCHED PRETTY WELL BY THE RAP WHICH DOESNT GIVE ANY POTENTIAL FOR THUNDER TIL VERY LATE THIS AFTN..IF AT ALL...IN SE PA/MD. SO NO THUNDER IN THE FCST TODAY. THE RAP WAS FURTHER NORTH THAN THE SPCWRF WITH ITS RAIN AREA AND OPTED FOR THE MORE EXPANSIVE SPC WRF DEPICTION OF RAINFALL AND A BAND OF MDT TO HEAVY EVEN DOWN TO PHL. 12Z HPCQPF HAS SPREAD THE AXIS OF HEAVY RAIN A BIT FURTHER SOUTH. THE DRIVERS FOR TODAYS RFALL ARE THE RRQ OF A NW FLOW 250 MB 80-90 KT SPEED MAX E OF CAPE COD AND THE INSTABILITY BURST ASSOCIATED AND DRIVEN BY A 35-40 KT WLY 700MB SPEED MAX (MOISTURE TRANSPORT) MOVING ACROSS PA WITH SW FLOW AT 850 MB AIDING LIFT. WHILE THE MOST PERSISTENT AND WIDESPREAD SHOWERS WITHOUT THUNDER SHOULD OCCUR NJ/PA NEAR THE AXIS OF THE 700MB JET SPEED MAX...THERE IS A CHANCE FOR A CONVECTIVE THUNDER OUTBREAK NEAR THE MASON DIXON LINE LATE THIS AFTN WHERE IT WILL HEAT UP S OF THE GENERAL SHOWER AREA... PRODUCING ABOUT 600J OF ML CAPE. REGARDING MOISTURE: THE PWAT AT 03Z/28 (11PM MONDAY) WAS ABOUT ONE HALF INCH AND IS MODELED TO INCREASE TO 1.5 INCHES BY LATE THIS TUE AFTN! TEMPS WINDS AND DEWPOINTS ARE BLENDED 00Z/28 NCEP MOS GUIDANCE AND HIGH TEMPS COULD BE A COUPLE OF DEGREES TOO WARM IN NNJ DEPENDING ON WHETHER ITS RAINING MUCH OF THE TIME BETWEEN 11 AM AND 5 PM. THE 610 AM UPDATE COOLED TEMPS SEVERAL DEGREES THERE. THE SFC WARM FRONT WILL EVOLVE NEWD AND BY 21Z LIE ROUGHLY FROM KDMH TO KMIV. STRONGER SLY WINDS TO 20-25 KT WILL OCCUR TO THE SOUTH OF THE WARMFRONT WHERE IT HEATS UP. LATEST COSPA...RAP-RUC AS WELL AS 00Z/28 SPC WRF WERE USED TO ASSIST IN THE FCST AND TIMING! 06Z/28 HPC QPF WAS ALSO APPLIED...ADJUSTED A BIT SWD IN E PA. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... SHOWERS WITH ISOLATED TSTMS ARE POSSIBLE PRIOR TO 06Z BUT CONFIDENCE ON TONIGHTS SHOWER SCENARIO IS BELOW AVERAGE. MOST OF THE RAINFALL SHOULD OCCUR PRIOR TO 00Z/29. THERE IS A SMALL CHANCE WE`LL NEED TO ISSUE AN SPS FOR A GROUP OF TSTMS...POSSIBLY A SEWD MOVING CONVECTIVE BAND CROSSING CHES BAY EARLY THIS TUE EVENING AND THEN ANOTHER EWD MOVING CONVECTIVE CLUSTER IN THE 35C KI ACROSS NNJ AROUND 06Z? THIS LATTER MIGHT BE THE SRN EDGE OF DIMINISHING NEAR SVR DRIVING EWD FROM THE UPPER OHIO VALLEY AS DISCUSSED IN THE 0602Z/28 SWODY1. TEMPS/WINDS/DEWPOINTS ARE 50 50 BLENDED 00Z/28 NCEP MOS MET/MAV GUIDANCE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... BUILDING H5 HEIGHTS AND A SFC HIGH WHICH WILL RIDGE BACK ACROSS THE AREA WILL BRING WARM AND INCREASINGLY HUMID AIR TO THE REGION BEGINNING WEDNESDAY AND LASTING INTO THE WEEKEND. THE FIRST HEAT WAVE OF THE SEASON MAY RESULT...BUT NO HEAT RELATED FLAGS HAVE BEEN ISSUED WITH THE OVERNIGHT FCST. WED...THE SHORTWAVE/WARM FRONT FEATURE FROM THE SHORT TERM WILL BE EXITING TO THE NORTH/EAST/ A FEW LINGERING SHOWERS MAY STILL AFFECT THE AREA ACROSS NRN NJ EARLY AND ALSO A FEW SCT TSTMS ARE POSSIBLE DURING THE AFTERNOON ACROSS THE NRN AREAS. ELSEWHERE...IT SHOULD REMAIN DRY AND VERY WARM. HIGHS MOSTLY IN THE MID/UPPER 80S WITH COOLER TEMPS AT THE BEACHES. WED NIGHT...DRY WITH LOWS IN THE LOW TO MID 60S NORTH AND MID TO UPPER 60S SOUTH. READINGS WILL HOLD NEAR 70 IN METRO PHILADELPHIA. THU THRU SAT...ESSENTIALLY A DRY FCST WITH THE UPPER RIDGE BUILDING ACROSS THE AREA THRU FRI BEFORE MOVING OFF TO THE EAST SAT. A FEW SHOWERS MAY AFFECT THE NRN MOST PART OF NJ THU EVENING WITH ONLY SLGT CHC POPS IN THE FCST. INCREASINGLY HOT AND HUMID WITH HIGHS IN THE UPPER 80S/LOW 90S THU AND LOWS MOSTLY IN THE UPPER 60S AND LOW 70S. SUN AND MON...THE HEAT WAVE BREAKS LATER SUN AFTER A DAY WITH HIGHS IN THE UPPER 80S. MORE CLOUDS AND BETTER CHCS FOR SHOWERS/TSTMS AS A SYNOPTIC SYSTEM CROSSES SRN CANADA AND SENDS A COLD FRONT ACROSS THE AREA LATER SUNDAY. HIGHS MON WILL MOSTLY BE IN UPPER 70S NORTH AND LOW 80S SOUTH. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY ...SHOWERS BECOMING WIDESPREAD KPHL NORTH THIS MORNING WITH MVFR CONDS DEVELOPING NEAR OR AFTER 17Z....POSSIBLY SPOTTY IFR CIGS BY 00Z/29. LIGHT WIND TENDING E OR SE THIS AFTN EXCEPT BECOMING SLY KMIV SOUTHWARD LATE IN THE DAY. TONIGHT...MVFR OR IFR CONDS IN ST/FOG KRDG KABE KTTN WITH MVFR CONDS ELSEWHERE IN SC/FOG/HAZE. CHANCE OF A SHOWER. SMALL CHANCE OF A TSTM. WIND GRADUALLY VEERING FROM SSE TO SW DURING THE NIGHT. OUTLOOK... WEDNESDAY...A FEW LINGERING SHOWERS FAR NORTH EARLY AND THEN A CHC FOR AN AFTERNOON TSTM N/W. VFR ELSEWHERE. THU THRU SAT...MOSTLY VFR. PATCHY FOG POSSIBLE AT NIGHT. && .MARINE... SUB-ADVISORY CONDITIONS WILL PERSIST ACROSS OUR WATERS FOR A BETTER PART OF TODAY. SEAS WILL SLOWLY INCREASE UPWARDS OF 4 FEET BY THIS AFTERNOON OFF DELAWARE AS A WARM FRONT LIFTS THROUGH THE REGION. WINDS ON THE OUTER ATLC WATERS OFF DELAWARE MIGHT GUST TO NEAR 25 KT LATE IN THE DAY. AN SCA WAS ISSUED ONLY WHERE CONFIDENCE REASONABLY HIGH THAT 5 FT SEAS WILL OCCUR. CONFIDENCE FOR MAX GUSTS REACHING 25 KT IS LESS THAN OUR SEEING 5 FT SEAS OFF DELAWARE TONIGHT. THE REMAINDER OF THE NJ WATERS MAY NEED AN SCA TONIGHT OR WED BUT FOR NOW...CONFIDENCE NOT HIGH ENOUGH TO ISSUE. OUTLOOK... MOSTLY SUB-SCA CONDITIONS WED-FRI...THEN INCREASING WINDS AND BUILDING SEAS THIS WEEKEND WITH SCA POSSIBLE. AS DEW POINT TEMPERATURES EXCEED THE WATER TEMPERATURES ALONG THE COASTS OF DELAWARE AND NEW JERSEY FROM WEDNESDAY THROUGH SATURDAY, THE COASTAL WATERS WILL BE SUSCEPTIBLE TO DEVELOPING FOG BANKS. && .RIP CURRENTS... TODAY...FCST LOW FOR NJ. KEPT THE ONSHORE GRADIENT WIND TO 15 KT OR LESS THIS AFTN. CERTAINLY STARTS OUT AS A LOW RISK WITH VIRTUALLY NO WIND OR SWELL TO START THE DAY. DELAWARE WILL ALSO BE A LOW RISK TODAY. 15 KT IS THE KEY TO THE ONSHORE WIND. BELOW 15 KT FAVORS LOW RISK. NO MATTER...EVEN AT LOW RISK...IF YOU DONT SWIM UNDER THE WATCHFUL EYE OF A LIFE GUARD...YOU COULD BE ASKING FOR TROUBLE. RIP CURRENTS CAN FORM ANYTIME...ESPECIALLY IN THE LOWER HALF OF THE TIDE CYCLE. THIS SHOULD BE KEPT IN MIND AS IT HEATS UP LATER IN THE WEEK! ALSO THE SSTS ARE COLD...LOWER 50S (LBI THIS MORNING) VARIABLE UP TO THE LOWER 60S. SWIM WITH SAFETY IN MIND! THE DAILY OUTLOOK FOR THE REST OF THE WEEK LOOKS TO BE A GENERALLY LOW RISK. TODAY...LOW OR MDT IN NJ AND LOW DE. DEPENDS ON THE WIND SPEED AND SWELL GROUP. 2FT 9SEC OR 4FT 6 SEC WILL GIVE MDT IF THE ONSHORE WIND REACHES 16 KT. IF THE SWELL SIZE OF EITHER GROUP OR THE WIND IS LESS THAN 16 KT...THE RISK DROPS TO LOW. WEDNESDAY...1FT 9 SEC OR 4 FT 6 SEC WIND 18013 LOW RISK THURSDAY...1 FT 8 SEC OR 4 FT 6 SEC WIND 18011 LOW RISK FRIDAY...1 FT 9 SEC OR 3 FT 5 SEC WIND 18011 LOW RISK SATURDAY...1FT 9 SEC OR 4FT 5 SEC WIND 21013. LOW RISK RIP CURRENT AWARENESS WEEK IS JUNE 2-8. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EDT WEDNESDAY FOR ANZ453>455. && $$ SYNOPSIS...O`HARA NEAR TERM...DRAG 619 SHORT TERM...DRAG 619 LONG TERM...O`HARA AVIATION...DRAG/O`HARA 619 MARINE...DRAG/O`HARA 619 RIP CURRENTS...619
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
506 AM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL LIFT ACROSS THE AREA THIS AFTERNOON AND EARLY TONIGHT. HIGH PRESSURE OFF THE EAST COAST WILL RIDGE BACK ACROSS OUR AREA FOR THE MIDDLE AND LATE PARTS OF THIS WEEK. LOW PRESSURE WILL MOVE NORTH OF THE REGION SATURDAY AND SUNDAY AND SEND A COLD FRONT ACROSS THE AREA EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TODAY...IT LOOKS AS THOUGH THE CONVECTIVE MODELS FROM NCEP HAVE AGAIN PREVAILED WHEN COMPARED TO YDYS 00Z/27 CYCLE OF THE RGEM/GGEM/ECMWF/UKMET. A DECENT SLUG OF SHOWERS IS FORECAST TODAY WITH A N/S BAND OF BRIEFLY MODERATE TO HEAVY RAIN SWEEPING EWD WITHIN THE GROWING AREA OF RAIN ACROSS PA/NJ. THE 00Z/28 SPC WRF IS TO MY OVERALL LIKING AND IS MATCHED PRETTY WELL BY THE RAP WHICH DOESNT GIVE ANY POTENTIAL FOR THUNDER TIL VERY LATE THIS AFTN..IF AT ALL...IN SE PA/MD. SO NO THUNDER IN THE FCST TODAY. THE RAP IS FURTHER NORTH THAN THE SPCWRF WITH ITS RAIN AREA AND AM OPTING FOR THE MORE EXPANSIVE SPC WRF DEPICTION OF RAINFALL AND A BAND OF MDT TO HEAVY EVEN DOWN TO PHL. 06Z HPCQPF WAS A LITTLE LESS THAN WHAT I THINK WILL HAPPEN IN PHL...BUT IF THE 700 MB SPEED MAX IS FURTHER NORTH THAN THE MASON DIXON LINE TODAY...THEN THE HEAVIER QPF WILL REMAIN UP NORTH....ALONG AND N OF RTE 80. THE DRIVERS FOR TODAYS RFALL ARE THE RRQ OF A NW FLOW 250 MB 80-90 KT SPEED MAX E OF CAPE COD AND THE INSTABILITY BURST ASSOCIATED AND DRIVEN BY A 35-40 KT WLY 700MB SPEED MAX (MOISTURE TRANSPORT) MOVING ACROSS PA WITH SW FLOW AT 850 MB AIDING LIFT. WHILE THE MOST PERSISTENT AND WIDESPREAD SHOWERS WITHOUT THUNDER SHOULD OCCUR NJ/PA NEAR THE AXIS OF THE 700MB JET SPEED MAX...THERE IS A CHANCE FOR A CONVECTIVE THUNDER OUTBREAK NEAR THE MASON DIXON LINE LATE THIS AFTN WHERE IT WILL HEAT UP S OF THE GENERAL SHOWER AREA... PRODUCING ABOUT 600J OF ML CAPE. REGARDING MOISTURE: THE PWAT AT 03Z/28 (11PM MONDAY) WAS ABOUT ONE HALF INCH AND IS MODELED TO INCREASE TO 1.5 INCHES BY LATE THIS TUE AFTN! TEMPS WINDS AND DEWPOINTS ARE BLENDED 00Z/28 NCEP MOS GUIDANCE AND HIGH TEMPS COULD BE 5 DEGREES TOO WARM IN NNJ DEPENDING ON WHETHER ITS RAINING MUCH OF THE TIME BETWEEN 11 AM AND 5 PM. I MAY RUN THESE NNJ TEMPS 5 DEGREES COOLER IN MY 630 AM ESTF UPDATE. THE SFC WARM FRONT WILL EVOLVE NEWD AND BY 21Z LIE ROUGHLY FROM KDMH TO KMIV. STRONGER SLY WINDS TO 20-25 KT WILL OCCUR TO THE SOUTH OF THE WARMFRONT WHERE IT HEATS UP. LATEST COSPA...RAP-RUC AS WELL AS 00Z/28 SPC WRF WERE USED TO ASSIST IN THE FCST AND TIMING! 06Z/28 HPC QPF WAS ALSO APPLIED...ADJUSTED A BIT SWD IN E PA. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... SHOWERS WITH ISOLATED TSTMS ARE POSSIBLE PRIOR TO 06Z BUT CONFIDENCE ON TONIGHTS SHOWER SCENARIO IS BELOW AVERAGE. MOST OF THE RAINFALL SHOULD OCCUR PRIOR TO 00Z/29. THERE IS A SMALL CHANCE WE`LL NEED TO ISSUE AN SPS FOR A GROUP OF TSTMS...POSSIBLY A SEWD MOVING CONVECTIVE BAND CROSSING CHES BAY EARLY THIS TUE EVENING AND THEN ANOTHER EWD MOVING CONVECTIVE CLUSTER IN THE 35C KI ACROSS NNJ AROUND 06Z? THIS LATTER MIGHT BE THE SRN EDGE OF DIMINISHING NEAR SVR DRIVING EWD FROM THE UPPER OHIO VALLEY AS DISCUSSED IN THE 0602Z/28 SWODY1. TEMPS/WINDS/DEWPOINTS ARE 50 50 BLENDED 00Z/28 NCEP MOS MET/MAV GUIDANCE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... BUILDING H5 HEIGHTS AND A SFC HIGH WHICH WILL RIDGE BACK ACROSS THE AREA WILL BRING WARM AND INCREASINGLY HUMID AIR TO THE REGION BEGINNING WEDNESDAY AND LASTING INTO THE WEEKEND. THE FIRST HEAT WAVE OF THE SEASON MAY RESULT...BUT NO HEAT RELATED FLAGS HAVE BEEN ISSUED WITH THE OVERNIGHT FCST. WED...THE SHORTWAVE/WARM FRONT FEATURE FROM THE SHORT TERM WILL BE EXITING TO THE NORTH/EAST/ A FEW LINGERING SHOWERS MAY STILL AFFECT THE AREA ACROSS NRN NJ EARLY AND ALSO A FEW SCT TSTMS ARE POSSIBLE DURING THE AFTERNOON ACROSS THE NRN AREAS. ELSEWHERE...IT SHOULD REMAIN DRY AND VERY WARM. HIGHS MOSTLY IN THE MID/UPPER 80S WITH COOLER TEMPS AT THE BEACHES. WED NIGHT...DRY WITH LOWS IN THE LOW TO MID 60S NORTH AND MID TO UPPER 60S SOUTH. READINGS WILL HOLD NEAR 70 IN METRO PHILADELPHIA. THU THRU SAT...ESSENTIALLY A DRY FCST WITH THE UPPER RIDGE BUILDING ACROSS THE AREA THRU FRI BEFORE MOVING OFF TO THE EAST SAT. A FEW SHOWERS MAY AFFECT THE NRN MOST PART OF NJ THU EVENING WITH ONLY SLGT CHC POPS IN THE FCST. INCREASINGLY HOT AND HUMID WITH HIGHS IN THE UPPER 80S/LOW 90S THU AND LOWS MOSTLY IN THE UPPER 60S AND LOW 70S. SUN AND MON...THE HEAT WAVE BREAKS LATER SUN AFTER A DAY WITH HIGHS IN THE UPPER 80S. MORE CLOUDS AND BETTER CHCS FOR SHOWERS/TSTMS AS A SYNOPTIC SYSTEM CROSSES SRN CANADA AND SENDS A COLD FRONT ACROSS THE AREA LATER SUNDAY. HIGHS MON WILL MOSTLY BE IN UPPER 70S NORTH AND LOW 80S SOUTH. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. PRIOR TO 12Z TUE...VFR CIGS WITH CIGS LOWERING TO 5000 FT SE PA AND DE IN ISOLATED SHOWERS. LIGHT WIND. AFTER 12Z TUE...SHOWERS BECOMING WIDESPREAD KPHL NORTH BY 15Z WITH MVFR CONDS DEVELOPING NEAR OR AFTER 17Z....POSSIBLY SPOTTY IFR CIGS BY 00Z/29. LIGHT WIND TENDING E OR SE THIS AFTN EXCEPT BECOMING SLY KMIV SOUTHWARD LATE IN THE DAY. TONIGHT...MVFR OR IFR CONDS IN ST/FOG KRDG KABE KTTN WITH MVFR CONDS ELSEWHERE IN SC/FOG/HAZE. CHANCE OF A SHOWER. SMALL CHANCE OF A TSTM. WIND GRADUALLY VEERING FROM SSE TO SW DURING THE NIGHT. OUTLOOK... WEDNESDAY...A FEW LINGERING SHOWERS FAR NORTH EARLY AND THEN A CHC FOR AN AFTERNOON TSTM N/W. VFR ELSEWHERE. THU THRU SAT...MOSTLY VFR. PATCHY FOG POSSIBLE AT NIGHT. && .MARINE... SUB-ADVISORY CONDITIONS WILL PERSIST ACROSS OUR WATERS FOR A BETTER PART OF TODAY. SEAS WILL SLOWLY INCREASE UPWARDS OF 4 FEET BY THIS AFTERNOON OFF DELAWARE AS A WARM FRONT LIFTS THROUGH THE REGION. WINDS ON THE OUTER ATLC WATERS OFF DELAWARE MIGHT GUST TO NEAR 25 KT LATE IN THE DAY. AN SCA WAS ISSUED ONLY WHERE CONFIDENCE REASONABLY HIGH THAT 5 FT SEAS WILL OCCUR. CONFIDENCE FOR MAX GUSTS REACHING 25 KT IS LESS THAN OUR SEEING 5 FT SEAS OFF DELAWARE TONIGHT. THE REMAINDER OF THE NJ WATERS MAY NEED AN SCA TONIGHT OR WED BUT FOR NOW...CONFIDENCE NOT HIGH ENOUGH TO ISSUE. OUTLOOK... MOSTLY SUB-SCA CONDITIONS WED-FRI...THEN INCREASING WINDS AND BUILDING SEAS THIS WEEKEND WITH SCA POSSIBLE. AS DEW POINT TEMPERATURES EXCEED THE WATER TEMPERATURES ALONG THE COASTS OF DELAWARE AND NEW JERSEY FROM WEDNESDAY THROUGH SATURDAY, THE COASTAL WATERS WILL BE SUSCEPTIBLE TO DEVELOPING FOG BANKS. && .RIP CURRENTS... FOR TODAY...SITTING ON THE THRESHOLD OF LOW OR MDT RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS IN NJ THIS AFTN. WILL DO A FINAL CHECK OF THE 06Z GFS WIND FCST FOR 18Z TODAY AND ISSUE THE SRF AT 550 AM EDT. CERTAINLY STARTS OUT AS A LOW RISK WITH VIRTUALLY NO WIND OR SWELL TO START THE DAY. DELAWARE WILL BE A LOW RISK TODAY. IF THE SFC WIND SPEED REMAINS BELOW 15 KT ALONG THE NJ COAST THIS AFTN...THAT WOULD FAVOR A LOWER RISK. NO MATTER...EVEN AT LOW RISK...IF YOU DONT SWIM UNDER THE WATCHFUL EYE OF A LIFE GUARD...YOU COULD BE ASKING FOR TROUBLE. RIP CURRENTS CAN FORM ANYTIME...ESPECIALLY IN THE LOWER HALF OF THE TIDE CYCLE. THIS SHOULD BE KEPT IN MIND AS IT HEATS UP LATER IN THE WEEK! ALSO THE SSTS ARE COLD...MID 50S TO LOWER 60S. SWIM WITH SAFETY IN MIND! THE DAILY OUTLOOK FOR THE REST OF THE WEEK LOOKS TO BE A GENERALLY LOW RISK. TODAY...LOW OR MDT IN NJ AND LOW DE. DEPENDS ON THE WIND SPEED AND SWELL GROUP. 2FT 9SEC OR 4FT 6 SEC WILL GIVE MDT IF THE ONSHORE WIND REACHES 16 KT. IF THE SWELL SIZE OF EITHER GROUP OR THE WIND IS LESS THAN 16 KT...THE RISK DROPS TO LOW. WEDNESDAY...1FT 9 SEC OR 4 FT 6 SEC WIND 18013 LOW RISK THURSDAY...1 FT 8 SEC OR 4 FT 6 SEC WIND 18011 LOW RISK FRIDAY...1 FT 9 SEC OR 3 FT 5 SEC WIND 18011 LOW RISK SATURDAY...1FT 9 SEC OR 4FT 5 SEC WIND 21013. LOW RISK RIP CURRENT AWARENESS WEEK IS JUNE 2-8. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EDT WEDNESDAY FOR ANZ453>455. && $$ SYNOPSIS...O`HARA NEAR TERM...DRAG 505 SHORT TERM...DRAG 505 LONG TERM...O`HARA AVIATION...DRAG/O`HARA 505 MARINE...DRAG/O`HARA 505 RIP CURRENTS...505
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
347 AM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL LIFT ACROSS THE AREA THIS AFTERNOON AND EARLY TONIGHT. HIGH PRESSURE OFF THE EAST COAST WILL RIDGE BACK ACROSS OUR AREA FOR THE MIDDLE AND LATE PARTS OF THIS WEEK. LOW PRESSURE WILL MOVE NORTH OF THE REGION SATURDAY AND SUNDAY AND SEND A COLD FRONT ACROSS THE AREA EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WAA CLOUD COVER WELL IN ADVANCE OF AN ACTIVE WARM FRONT AND ALSO IN THE RRQ OF THE 250MB NW FLOW 80-90KT SPEED MAX ROUGHLY CENTERED OVER LONG ISLAND IS RESPONSIBLE FOR OVERNIGHT TEMPERATURES NEARLY 10 DEGREES WARMER THAN EARLY THIS PAST MONDAY MORNING WHEN SPOTTY FROST APPEARED TO HAVE OCCURRED FROM THE POCONOS TO SUSSEX AND WARREN COUNTIES IN NJ. TODAY-TUESDAY...IT LOOKS AS THOUGH THE CONVECTIVE MODELS FROM NCEP HAVE AGAIN PREVAILED WHEN COMPARED TO YDYS 00Z/27 CYCLE OF THE RGEM/GGEM/ECMWF/UKMET. A DECENT SLUG OF SHOWERS IS FORECAST TODAY WITH A N/S BAND OF BRIEFLY MDT TO BRIEFLY RAIN SWEEPING EWD WITHIN THE GROWING AREA OF RAIN ACROSS PA/NJ. THE 00Z/28 SPC WRF IS TO MY OVERALL LIKING AND IS MATCHED PRETTY WELL BY THE RAP WHICH DOESNT GIVE ANY POTENTIAL FOR THUNDER TIL VERY LATE THIS AFTN..IF AT ALL...IN SE PA/MD. SO NO THUNDER IN THE FCST TODAY. THE RAP IS FURTHER NORTH THAN THE SPCWRF AND I AM OPTING FOR THE MORE EXPANSIVE SPC WRF DEPICTION OF RAINFALL AND A BAND OF MDT TO HEAVY EVEN DOWN TO PHL. 06Z HPC QPF IS A LITTLE LESS THAN WHAT I THINK WILL HAPPEN IN PHL...BUT IF THE 700 MB SPEED MAX IS FURTHER NORTH THAN THE MASON DIXON LINE TODAY...THEN THE HEAVIER QPF WILL REMAIN UP NORTH. THE DRIVERS FOR TODAYS RFALL ARE THE RRQ OF THE PGH 1 MENTIONED NW FLOW UPPER LVL JET SPEED MAX MOVING E OF CAPE COD AND THE INSTABILITY BURST DRIVEN ASSOCIATED BY A 35-40 KT WLY 700MB SPEED MAX (MOISTURE TRANSPORT) MOVING ACROSS PA WITH SW FLOW AT 850 MB AIDING LIFT. WHILE THE MOST PERSISTENT AND WIDESPREAD SHOWERS WITHOUT THUNDER SHOULD OCCUR NJ/PA NEAR THE AXIS OF THE 700MB JET SPEED MAX...THERE IS A CHANCE FOR A CONVECTIVE THUNDER OUTBREAK NEAR THE MASON DIXON LINE LATE THIS AFTN WHERE IT WILL HEAT UP S OF THE GENERAL SHOWER AREA...PRODUCING ABOUT 600J OF ML CAPE. REGARDING MOISTURE: THE PWAT AT 03Z/28 (11PM MONDAY) WAS ABOUT ONE HALF INCH AND IS MODELED TO INCREASE TO 1.5 INCHES BY LATE THIS TUE AFTN! TEMPS WINDS AND DEWPOINTS ARE BLENDED 00Z/28 NCEP MOS GUIDANCE AND HIGH TEMPS COULD BE 5 DEGREES TOO WARM IN NNJ DEPENDING ON WHETHER ITS RAINING MUCH OF THE TIME BETWEEN 11 AM AND 5 PM. I MAY RUN THESE TEMPS COOLER IN MY 630 AM ESTF UPDATE. THE SFC WARM FRONT WILL EVOLVE NEWD AND BY 21Z LIE ROUGHLY FROM KDMH TO KMIV. STRONGER SLY WINDS TO 20-25 KT WILL OCCUR TO THE SOUTH OF THE WARMFRONT WHERE IT HEATS UP. LATEST COSPA...RAP-RUC AS WELL AS 00Z/28 SPC WRF WERE USED TO ASSIST IN THE FCST AND TIMING! 06Z/28 HPC QPF WAS ALSO APPLIED...ADJUSTED A BIT SWD IN E PA. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... SHOWERS WITH ISOLATED TSTMS ARE POSSIBLE PRIOR TO 06Z BUT CONFIDENCE ON TONIGHTS SCENARIO IS BELOW AVERAGE. MOST OF THE RAINFALL SHOULD BE PRIOR TO 00Z/29. THERE IS A SMALL CHANCE WE`LL NEED TO ISSUE AN SPS FOR A GROUP OF TSTMS...POSSIBLY A SEWD MOVING CONVECTIVE BAND CROSSING CHES BAY EARLY THIS TUE EVENING AND THEN ANOTHER EWD MOVING CONVECTIVE CLUSTER IN THE 35C KI ACROSS NNJ AROUND 06Z? THIS LATTER MIGHT BE THE SRN EDGE OF DIMINISHING NEAR SVR DRIVING EWD FROM THE UPPER OHIO VALLEY AS DISCUSSED IN THE 0602Z SWODY1. TEMPS/WINDS/DEWPOINTS ARE 50 50 BLENDED 00Z/28 NCEP MOS MET/MAV GUIDANCE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... BUILDING H5 HEIGHTS AND A SFC HIGH WHICH WILL RIDGE BACK ACROSS THE AREA WILL BRING WARM AND INCREASINGLY HUMID AIR TO THE REGION BEGINNING WEDNESDAY AND LASTING INTO THE WEEKEND. THE FIRST HEAT WAVE OF THE SEASON MAY RESULT...BUT NO HEAT RELATED FLAGS HAVE BEEN ISSUED WITH THE OVERNIGHT FCST. WED...THE SHORTWAVE/WARM FRONT FEATURE FROM THE SHORT TERM WILL BE EXITING TO THE NORTH/EAST/ A FEW LINGERING SHOWERS MAY STILL AFFECT THE AREA ACROSS NRN NJ EARLY AND ALSO A FEW SCT TSTMS ARE POSSIBLE DURING THE AFTERNOON ACROSS THE NRN AREAS. ELSEWHERE...IT SHOULD REMAIN DRY AND VERY WARM. HIGHS MOSTLY IN THE MID/UPPER 80S WITH COOLER TEMPS AT THE BEACHES. WED NIGHT...DRY WITH LOWS IN THE LOW TO MID 60S NORTH AND MID TO UPPER 60S SOUTH. READINGS WILL HOLD NEAR 70 IN METRO PHILADELPHIA. THU THRU SAT...ESSENTIALLY A DRY FCST WITH THE UPPER RIDGE BUILDING ACROSS THE AREA THRU FRI BEFORE MOVING OFF TO THE EAST SAT. A FEW SHOWERS MAY AFFECT THE NRN MOST PART OF NJ THU EVENING WITH ONLY SLGT CHC POPS IN THE FCST. INCREASINGLY HOT AND HUMID WITH HIGHS IN THE UPPER 80S/LOW 90S THU AND LOWS MOSTLY IN THE UPPER 60S AND LOW 70S. SUN AND MON...THE HEAT WAVE BREAKS LATER SUN AFTER A DAY WITH HIGHS IN THE UPPER 80S. MORE CLOUDS AND BETTER CHCS FOR SHOWERS/TSTMS AS A SYNOPTIC SYSTEM CROSSES SRN CANADA AND SENDS A COLD FRONT ACROSS THE AREA LATER SUNDAY. HIGHS MON WILL MOSTLY BE IN UPPER 70S NORTH AND LOW 80S SOUTH. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. PRIOR TO 12Z TUE...VFR CIGS WITH CIGS LOWERING TO 5000 FT SE PA AND DE IN ISOLATED SHOWERS NEAR 12Z. LIGHT WIND. AFTER 12Z TUE...SHOWERS BECOMING WIDESPREAD KPHL NORTH BY 16Z WITH MVFR CONDS DEVELOPING NEAR OR AFTER 17Z....POSSIBLY SPOTTY IFR CIGS BY 00Z/29. LIGHT WIND TENDING E OR SE THIS AFTN EXCEPT BECOMING SLY KMIV SOUTHWARD LATE IN THE DAY. TONIGHT...MVFR OR IFR CONDS IN ST/FOG KRDG KABE KTTN WITH MVFR CONDS ELSEWHERE IN SC/FOG/HAZE. CHANCE OF A SHOWER. SMALL CHANCE OF A TSTM. WIND GRADUALLY VEERING FROM SSE TO SW DURING THE NIGHT. OUTLOOK... WEDNESDAY...A FEW LINGERING SHOWERS FAR NORTH EARLY AND THEN A CHC FOR AN AFTERNOON TSTM N/W. VFR ELSWEHERE. THU THRU SAT...MOSTLY VFR. PATCHY FOG POSSIBLE AT NIGHT. && .MARINE... SUB-ADVISORY CONDITIONS WILL PERSIST ACROSS OUR WATERS FOR A BETTER PART OF TODAY. SEAS WILL SLOWLY INCREASE UPWARDS OF 4 FEET BY THIS AFTERNOON OFF DE AS A WARM FRONT LIFTS THROUGH THE REGION. WINDS ON THE OUTER ATLC WATERS OFF DE MIGHT GUST TO NEAR 25 KT LATE IN THE DAY. AN SCA WAS ISSUED ONLY WHERE CONFIDENCE REASONABLY HIGH THAT 5 FT SEAS WILL OCCUR. CONFIDENCE FOR MAX GUSTS REACHING 25 KT IS LESS THAN OUR SEEING 5 FT SEAS OFF DE TONIGHT. THE REMAINDER OF THE NJ WATERS MAY NEED AN SCA TONIGHT OR WED BUT FOR NOW...CONFIDENCE NOT HIGH ENOUGH TO ISSUE. OUTLOOK... MOSTLY SUB-SCA CONDITIONS WED-FRI...THEN INCREASING WINDS AND BUILDING SEAS THIS WEEKEND WITH SCA POSSIBLE. AS DEW POINT TEMPERATURES EXCEED THE WATER TEMPERATURES ALONG THE COASTS OF DELAWARE AND NEW JERSEY FROM WEDNESDAY THROUGH SATURDAY, THE COASTAL WATERS WILL BE SUSCEPTIBLE TO DEVELOPING FOG BANKS. && .RIP CURRENTS... PROBABLY GOING LOW RISK TODAY. THE RISK MAY SHIFT UP TO MDT IN NJ IF THE SE WIND CAN INCREASE PAST 15 KT THIS AFTN. WILL OFFER AN OUTLOOK FOR THE REST OF THE WEEK AT 5AM. RIP CURRENT AWARENESS WEEK IS JUNE 2-8. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EDT WEDNESDAY FOR ANZ453>455. && $$ SYNOPSIS...O`HARA NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...O`HARA AVIATION...DRAG/O`HARA MARINE...DRAG/O`HARA RIP CURRENTS...DRAG
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
201 AM EDT TUE MAY 28 2013 .SYNOPSIS... HIGH PRESSURE HAS MOVED OFF THE MID ATLANTIC COAST. A WARM FRONT DEVELOPING FROM THE OHIO VALLEY TO THE DELMARVA IS FORECAST TO MOVE NORTHEAST THROUGH OUR REGION TONIGHT. A RIDGE OF WARM HIGH PRESSURE TO OUR SOUTH WILL GOVERN OUR WEATHER WEDNESDAY THROUGH SUNDAY. A COLD FRONT FROM THE NORTHWEST IS ANTICIPATED TO ARRIVE ON MONDAY. && .NEAR TERM /THROUGH TODAY/... WAA CLOUD COVER WELL IN ADVANCE OF AN ACTIVE WARM FRONT AND ALSO IN THE RRQ OF THE 250MB NW FLOW 80-90KT SPEED MAX ROUGHLY CENTERED OVER LONG ISLAND IS RESPONSIBLE FOR OVERNIGHT TEMPERATURES NEARLY 10 DEGREES WARMER THAN EARLY THIS PAST MONDAY MORNING WHEN SPOTTY FROST APPEARED TO HAVE OCCURRED FROM THE POCONOS TO SUSSEX AND WARREN COUNTIES IN NJ. TODAY-TUESDAY...IT LOOKS AS THOUGH THE CONVECTIVE MODELS FROM NCEP HAVE AGAIN PREVAILED WHEN COMPARED TO YDYS 00Z/27 CYCLE OF THE RGEM/GGEM/ECMWF/UKMET. A DECENT SLUG OF SHOWERS IS FORECAST TODAY WITH A N/S BAND OF BRIEFLY MDT TO BRIEFLY RAIN SWEEPING EWD WITHIN THE GROWING AREA OF RAIN ACROSS PA/NJ. THE 00Z/28 SPC WRF IS TO MY OVERALL LIKING AND IS MATCHED PRETTY WELL BY THE RAP WHICH DOESNT GIVE ANY POTENTIAL FOR THUNDER TIL VERY LATE THIS AFTN..IF AT ALL...IN SE PA/MD. THE DRIVERS ARE THE RRQ OF THE AFOREMENTIONED NW FLOW UPPER LVL JET SPEED MAX MOVING E OF CAPE COD AND THE INSTABILITY BURST DRIVEN ASSOCIATED WITH AND DRIVEN BY A 35-40 KT WLY 700MB SPEED MAX (MOISTURE TRANSPORT) MOVING ACROSS PA WITH SW FLOW AT 850 MB AIDING LIFT. THE MOST PERSISTENT AND WIDESPREAD SHOWERS WITHOUT THUNDER SHOULD OCCUR NJ/PA NEAR THE AXIS OF THE 700MB JET SPEED MAX HOWEVER...THERE IS A CHANCE FOR A CONVECTIVE THUNDER OUTBREAK NEAR THE MASON DIXON LINE LATE THIS AFTN WHERE IT WILL HEAT UP WITH ABOUT 600J OF ML CAPE. REGARDING MOISTURE: THE PWAT AT 03Z/28 (11PM MONDAY) WAS ABOUT ONE HALF INCH AND IS MODELED TO INCREASE TO 1.5 INCHES BY LATE THIS TUE AFTN! TEMPS WINDS AND DEWPOINTS ARE BLENDED 00Z/28 NCEP MOS GUIDANCE AND HIGH TEMPS COULD BE ERRONEOUS BY 5 DEGREES DEPENDING ON WHETHER ITS RAINING MUCH OF THE TIME BETWEEN 11 AM AND 5 PM. THE SFC WARM FRONT WILL EVOLVE NEWD AND BY 21Z LIE ROUGHLY FROM KDMH TO KMIV. LATEST COSPA...RAP-RUC AS WELL AS 00Z/28 SPC WRF ARE USED TO ASSIST IN THE FCST AND TIMING! 2800 AND 2806Z HPC QPF WILL ALSO BE UTILIZED. && .SHORT TERM /TONIGHT/... SHOWERS WITH ISOLATED TSTMS ARE POSSIBLE PRIOR TO 06Z BUT MY CONFIDENCE ON TONIGHTS SCENARIO IS BELOW AVERAGE. MOST OF THE RAINFALL SHOULD BE PRIOR TO 00Z/29. THERE IS A SMALL CHANCE WE`LL NEED TO ISSUE AN SPS FOR A GROUP OF TSTMS...POSSIBLY A SEWD MOVING CONVECTIVE BAND CROSSING CHES BAY EARLY THIS TUE EVENING AND THEN ANOTHER EWD MOVING CONVECTIVE CLUSTER IN THE 35C KI ACROSS NNJ AROUND 06Z? TEMPS/WINDS/DEWPOINTS ARE 50 50 BLENDED 00Z/28 NCEP MOS MET/MAV GUIDANCE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... A MID LEVEL RIDGE WILL BUILD TOWARD OUR REGION FROM THE WEST DURING THE PERIOD FROM TUESDAY NIGHT THROUGH THURSDAY NIGHT. THE RIDGE IS EXPECTED TO CREST OVERHEAD ON FRIDAY AND IT WILL LIKELY INFLUENCE OUR WEATHER INTO THE WEEKEND. A MID LEVEL TROUGH IS ANTICIPATED TO PASS ACROSS THE GREAT LAKES ON SUNDAY AND IT SHOULD REACH THE NORTHEASTERN STATES ON MONDAY. AS THE MID LEVEL IMPULSE PASSES TO OUR EAST ON WEDNESDAY MORNING, THE SHOWERS AND CLOUDS ARE EXPECT TO FOLLOW. WE ARE ANTICIPATING SOME CLEARING FOR WEDNESDAY. AS CONDITIONS DESTABILIZE DURING THE AFTERNOON HOURS THERE MAY BE SCATTERED TO ISOLATED THUNDERSTORMS, ESPECIALLY ALONG THE INTERSTATE 95 CORRIDOR AND AT POINTS TO THE NORTHWEST. CONDITIONS ARE EXPECTED TO REMAIN FAIRLY STABLE NEAR THE COAST AND OVER THE RELATIVELY COOL WATER. THE POTENTIAL FOR THE FIRST HEAT WAVE OF THE SEASON CONTINUES TO EXIST FOR WEDNESDAY THROUGH SUNDAY IN MUCH OF OUR REGION. WARM TEMPERATURES AT 850 HPA, MAINLY IN THE +15C TO +17C RANGE, ARE EXPECTED TO ARRIVE ON WEDNESDAY AND THEY SHOULD REMAIN OVERHEAD THROUGH SUNDAY. THE WARMEST OF THE AIR WITH 850 HPA TEMPERATURES NEAR +18C ARE FORECAST TO BE OVER OUR REGION IN THE FRIDAY INTO SATURDAY TIME FRAME AS THE MID LEVEL RIDGE CRESTS OVERHEAD. DAYTIME MAXIMUM TEMPERATURES AROUND 90 DEGREES ARE ANTICIPATED EACH DAY EXCEPT IN THE ELEVATED TERRAIN UP NORTH AND AT AREAS RIGHT ALONG THE COAST. WHERE TEMPERATURES REACH THE 90 DEGREE NEIGHBORHOOD, HEAT INDEX VALUES ARE ANTICIPATED TO BE IN THE 90 TO 95 DEGREE RANGE BASED ON THE CURRENT DEW POINT FORECASTS. OVERNIGHT MINIMUM READINGS SHOULD BE MOSTLY IN THE 60S DUE TO THE INCREASED HUMIDITY. HIGHLY URBANIZED LOCATIONS MAY NOT GET ANY LOWER THAN THE LOWER 70S. CONVECTIVE DEVELOPMENT SHOULD BE RATHER LIMITED ON THURSDAY, FRIDAY AND SATURDAY WITH THE RIDGE PASSING OVER OUR REGION. AS THE MID LEVEL TROUGH BEGINS TO APPROACH FROM THE NORTHWEST ON SUNDAY, WE MAY BEGIN TO SEE AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON HOURS, ESPECIALLY IN OUR NORTHWESTERN COUNTIES. A SLOW MOVING COLD FRONT, ASSOCIATED WITH THE APPROACHING MID LEVEL TROUGH, IS FORECAST TO ARRIVE IN OUR REGION ON MONDAY. IT IS EXPECTED TO BE ACCOMPANIED BY ADDITIONAL SHOWERS AND THUNDERSTORMS AS IT BRINGS AN END TO THE HEAT WAVE. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. PRIOR TO 12Z TUE...VFR CIGS WITH CIGS LOWERING TO 5000 FT SE PA AND DE IN ISOLATED SHOWERS NEAR 12Z. LIGHT WIND. AFTER 12Z TUE...SHOWERS BECOMING WIDESPREAD KPHL NORTH BY 16Z WITH MVFR CONDS DEVELOPING NEAR OR AFTER 17Z....POSSIBLY SPOTTY IFR CIGS BY 00Z/29. LIGHT WIND TENDING E OR SE THIS AFTN EXCEPT BECOMING SLY KMIV SOUTHWARD LATE IN THE DAY. TONIGHT...MVFR OR IFR CONDS IN ST/FOG KRDG KABE KTTN WITH MVFR CONDS ELSEWHERE IN SC/FOG/HAZE. CHANCE OF A SHOWER. SMALL CHANCE OF A TSTM. WIND GRADUALLY VEERING FROM SSE TO SW DURING THE NIGHT. OUTLOOK... EARLY WEDNESDAY MORNING...CEILING AND VISIBILITY VALUES LOWERING TO MVFR AS A WARM FRONT WITH SHOWERS AND SCATTERED THUNDERSTORMS LIFTS THROUGH OUR REGION. LATE WEDNESDAY MORNING AND WEDNESDAY AFTERNOON...MAINLY VFR WITH A CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS, ESPECIALLY FROM THE INTERSTATE 95 CORRIDOR NORTHWESTWARD. WEDNESDAY NIGHT THROUGH SATURDAY...MAINLY VFR WITH POSSIBLE MVFR CONDITIONS IN HAZE AND FOG DURING THE LATE NIGHT AND EARLY MORNING HOURS. && .MARINE... SUB-ADVISORY CONDITIONS WILL PERSIST ACROSS OUR WATERS FOR A BETTER PART OF TODAY. SEAS WILL SLOWLY INCREASE UPWARDS OF 4 FEET BY THIS AFTERNOON AS A WARM FRONT LIFTS THROUGH THE REGION. WINDS ON THE OUTER ATLC WATERS MIGHT GUST TO NEAR 25 KT LATE IN THE DAY. AN SCA MAY BE NEEDED IN OUR 330 AM FCST FOR THE DE AND SNJ ATLC WATERS... MAINLY FOR SEAS. IF AN SCA IS ISSUED FOR THE S NJ AND DE WATERS...IT WILL LAST THROUGH TONIGHT FOR G20-25 KT AND SEAS BUILDING TO 6 FT. CONFIDENCE FOR AN SCA IN THOSE WATERS IS ROUGHLY 70 PCT. OUTLOOK... A WARM FRONT IS EXPECTED TO LIFT THROUGH OUR REGION ON TUESDAY NIGHT FOLLOWED BY HIGH PRESSURE FOR WEDNESDAY THROUGH SATURDAY. WIND SPEEDS AND WAVE HEIGHTS WILL LIKELY REMAIN BELOW THE SMALL CRAFT ADVISORY CRITERIA THROUGH MOST OF THE PERIOD. WAVE HEIGHTS ON OUR OCEAN WATERS MAY BUILD NEAR 5 FEET ON SATURDAY IN THE PERSISTENT SOUTHERLY FLOW. AS DEW POINT TEMPERATURES EXCEED THE WATER TEMPERATURES ALONG THE COASTS OF DELAWARE AND NEW JERSEY FROM WEDNESDAY THROUGH SATURDAY, THE COASTAL WATERS WILL BE SUSCEPTIBLE TO DEVELOPING FOG BANKS. && .RIP CURRENTS... HAVE A MDT FCST FOR NJ TODAY. WILL CHECK THIS AGAIN AT 5AM AND OFFER AN OUTLOOK FOR THE REST OF THE WEEK. RIP CURRENT AWARENESS WEEK IS JUNE 2-8. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...DRAG/IOVINO 2A NEAR TERM...DRAG 2A SHORT TERM...DRAG 2A LONG TERM...IOVINO AVIATION...DRAG/IOVINO 2A MARINE...DRAG/IOVINO 2A RIP CURRENTS...2A
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
340 AM EDT Tue May 28 2013 .NEAR TERM [Through Tonight]... Yet another fair, hot, and dry day is in store for the Tri-State region today, with high temps once again expected to reach the middle 80s near the coast to the lower 90s further inland. Also, the sea breeze is expected to begin a bit earlier today, as it will be aided by increasing low level southeasterly winds, as the ridge of High Pressure off of the Mid-Atlantic continues to slide further to our east. Although deep layer moisture will still be quite limited, an isolated shower or thunderstorm cannot be ruled out this afternoon, especially across far western portions of the CWA, where most of the Hi-Res WRF runs are indicating some convective development. However, given that PWATs are still only expected to be around 1 inch, our confidence was not high enough to include explicit PoPs at this time, but would not be surprised if the day shift modifies this forecast slightly. For tonight, with slightly increasing low level moisture, the chances for fog or low clouds will be slightly higher than this morning, but probabilities are still not high enough to include any fog in the grids. However, this will change for Wednesday Night and Thursday Morning. && .SHORT TERM [Wednesday Through Thursday]... High pressure will remain centered off the Southeast U.S. coast and ridge westward across Dixie with the axis mainly north of the forecast area through this period. We will continue to see a very gradual moistening trend with isolated sea breeze showers or thunderstorms possible each afternoon. Daytime temps have been running above guidance and will remain a bit above seasonal levels. Look for highs in the lower 90s and overnight lows in the mid 60 to around 70 inland and in the lower to mid 70s at the coast. && .LONG TERM [Thursday Night through Monday]... A broad area of high pressure over the Southeast US and Atlantic Ocean will remain in place from Thursday through the weekend, resulting in easterly flow and lower than normal chances of precipitation. The best chance at seeing isolated thunderstorms will be in the eastern part of our CWA during this period, where the Atlantic sea breeze may spark some convection each afternoon and early evening as it collides with the Gulf sea breeze. Seasonable temperatures should occur throughout the period, with highs generally in the low 90s and lows in the mid-upper 60s. Looking ahead to next week, a disturbance in the southern Gulf and Caribbean is being shown by the GFS, but it is far too early to determine the track or intensity of this possible feature. && .AVIATION... [Through 12 UTC Wednesday] VFR conditions are expected to prevail at the terminals for the overnight and daytime hours today, except for the potential of MVFR Cigs at VLD, TLH, and ECP. Confidence for this occurrence is not very high as the HRRR and NARRE are not in their usual good agreement, but the MAV guidance does support a brief period of 2500ft Cigs. The models are, however, in very good agreement about fog potential, and they have backed off substantially from this time last night to a high confidence of VFR as the air mass is remaining quite dry. Chances for MVFR to potentially IFR conditions may be a bit higher for late tonight and Wednesday morning, so may hint in the MVFR direction. && .MARINE... A ridge of high pressure will remain along or north of the Gulf Coast through the period with a prolonged period of easterly flow continuing. As is typical in this flow regime, there will be periods where wind speeds surge to cautionary or marginal advisory levels, mainly during the overnight and morning hours each day. && .FIRE WEATHER... With low level moisture gradually on the increase, no Red Flag concerns are expected for the next several days. However, with relatively high mixing heights and increasing transport wind speeds, dispersions are expected to be high across parts of the Tri-State area. && .HYDROLOGY... Overall chances for and coverage of showers and thunderstorms will be low through the weekend with no impacts to area rivers expected. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 92 68 91 70 92 / 0 0 10 10 20 Panama City 85 73 88 73 89 / 10 0 20 10 10 Dothan 91 65 92 68 91 / 10 10 10 10 20 Albany 91 65 92 68 92 / 0 0 10 10 10 Valdosta 92 65 92 67 91 / 0 0 20 10 20 Cross City 91 67 91 67 92 / 10 10 30 10 20 Apalachicola 84 72 87 73 88 / 10 0 10 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Weather...Gould Long Term...Lahr/Godsey Rest of Discussion...Wool
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
800 PM EDT WED MAY 29 2013 .UPDATE... NO CHANGES PLANNED FOR THE FORECAST EXCEPT SOME MINOR TWEAKS TO SKY COVER. 41 .PREVIOUS... .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... CURRENT SATELLITE LOOP SHOWS BKN TO OVC ACROSS THE AREA WITH THE CLOUDS ROTATING AROUND THE HIGH PRESSURE RIDGE. THE SURFACE AND UPPER LEVEL RIDGES ARE ALMOST VERTICALLY STACKED WHICH IS DOING A VERY GOOD JOB OF KEEPING ANY CU DEVELOPMENT FROM BECOMING A SHOWER/THUNDERSTORM. EVEN WITH THE GOOD MOIST EASTERLY FLOW THIS RIDGE SHOULD KEEP UP PRECIPITATION FREE THROUGH THE SHORT TERM. A FEW OF OUR LOCAL MODELS...THE HRRR AND THE LOCAL WRF...ARE TRYING TO SHOW SOME SHOWERS DEVELOPING THIS AFTERNOON ACROSS OUR SOUTHEASTERN COUNTIES. BOTH OF THESE MODELS APPEAR TO BE PICKING UP ON WHAT LOOKS TO BE A SEA BREEZE FRONT AND BRINGS IN SO LIGHT SHOWERS THIS AFTERNOON. THE RIDGE IS FIRMLY ENTRENCHED ACROSS SE GA SO I WOULD TEND TO RULE OUT ANY PRECIP TODAY OR THURSDAY. FOR NOW AM KEEPING ANY PRECIP WORDING OUT WITH POPS REMAINING BELOW 15 PERCENT. WITH THE MOIST EASTERLY FLOW WE WILL SEE INCREASED CLOUD COVER AGAIN THURSDAY WITH SOME LOW STRATUS MOVING IN TONIGHT. THESE LOW CLOUDS WILL KEEP TEMPS UP A LITTLE HIGHER THAN THE PAST COUPLE OF NIGHTS WITH MAX TEMPS THROUGH THURSDAY STAY IN THE 80S AND 90S. 01 .LONG TERM /FRIDAY THROUGH WEDNESDAY/... MAINLY ONLY TWEAKS TO THE LONG TERM. CAN NOT COMPLETELY RULE OUT SMALL CHANCES FOR SHOWERS/STORMS FRIDAY AFTERNOON OVER THE WESTERN CWA AND SATURDAY AFTERNOON FOR MUCH OF N AND CENTRAL GA. SHOWERS AND STORMS STILL MOST LIKELY SUNDAY AND MONDAY. BDL PREVIOUS DISCUSSION... ECMWF AND GFS IN GOOD AGREEMENT INTO THE WEEKEND WITH DIFFERENCES DEVELOPING AT THE EARLY PART OF NEXT WEEK. THE H5 RIDGE MAINTAINS ITS HOLD OVER THE CWA THROUGH FRIDAY...THEN THE RIDGE BEGINS TO BREAK DOWN AS THE UPPER TROUGH MOVES INTO THE MIDWEST. THIS WILL DRIVE A COLD FRONT INTO THE TENNESSEE AND OHIO VALLEYS LATE SATURDAY AND INTO SUNDAY AND MONDAY. THE ECMWF IS A LITTLE FASTER AND BRINGS MOISTURE WITH THE FRONT INTO THE CWA LATE SATURDAY NIGHT. BOTH MODELS PROG THE FRONT TO TAP INTO GULF MOISTURE SUNDAY BRINGING A GOOD CHANCE OF PRECIP TO MUCH OF THE CWA. DIFFERENCES DEVELOP SUNDAY NIGHT/MONDAY ON THE SPEED OF EXITING THE FRONT AND ASSOCIATED MOISTURE. THE ECMWF PUSHES THE FRONT THROUGH BUT THE SOUTHEAST CORNER OF THE CWA BY 12Z MONDAY WHILE THE GFS HOLDS THE FRONT BACK CLEARING ONLY THE NORTHWEST PART OF THE CWA BY 12Z MON AND THEN DEVELOPS A SECONDARY UPPER WAVE THAT INCREASES MOISTURE OVER MOST OF THE CWA DURING THE DAY MONDAY. AT THIS POINT WILL MAINTAIN HIGH POPS SUNDAY AND MONDAY AND BRING LOW OR NO POPS ON TUESDAY. 17 && .AVIATION... 00Z UPDATE... MOIST EASTERLY FLOW WILL CONTINUE ACROSS THE AREA. EXPECT CEILINGS TO FORM IN THE 008 TO 010 RANGE FROM 10Z TO 14Z...GRADUALLY SCATTERING OUT TO VFR AFTER 17Z. NO CONVECTION EXPECTED THROUGH THE PERIOD. VARIABLE TO LIGHT SOUTHEAST WINDS OVERNIGHT BECOMING EAST SOUTHEAST 8 TO 10KT AFTER 14Z THURSDAY. //ATL CONFIDENCE...00Z UPDATE... CONFIDENCE HIGH ON ALL ELEMENTS 41 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 64 87 66 85 / 5 5 5 10 ATLANTA 67 85 66 85 / 5 5 5 10 BLAIRSVILLE 60 83 63 82 / 5 5 5 10 CARTERSVILLE 65 86 66 85 / 5 5 10 20 COLUMBUS 68 88 68 89 / 10 10 10 20 GAINESVILLE 65 83 66 83 / 5 5 5 10 MACON 66 88 66 88 / 5 5 5 10 ROME 65 87 66 85 / 5 10 10 30 PEACHTREE CITY 65 86 66 85 / 5 5 5 10 VIDALIA 68 90 67 90 / 5 5 5 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...41 LONG TERM....BDL AVIATION...41
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
127 AM EDT TUE MAY 28 2013 .PREV DISCUSSION... /ISSUED 900 PM EDT MON MAY 27 2013/ UPDATE...HAVE REMOVED THUNDERSTORMS FROM THE FORECAST FOR THIS EVENING. OTHERWISE NO CHANGES. 41 PREVIOUS... SHORT TERM /TONIGHT THROUGH WEDNESDAY/... LATEST RUC 50H FIELD OVERLAID ON SATELLITE WATER VAPOR IMAGERY SHOWS SUBTLE DISTURBANCES EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT. SURFACE ANALYSIS SHOWS THE SURFACE RIDGE SETTLING ALONG THE MID ATLANTIC COAST AND ESTABLISHING A MOIST SOUTHERLY WIND FLOW THIS AFTERNOON. A MODIFIED 12Z FFC SOUNDING AND SUPPORTED BY LATEST SPC MESO ANALYSIS INDICATE AFTERNOON CAPES WILL TOP OUT AROUND 500-600 J/KG WITH A MODERATE MID LEVEL CAP. WEAK INSTABILITY... LACK OF DEEP LAYER SHEAR AND FORCING SUGGEST THE GREATER CHANCE FOR ISOLATED AFTERNOON EVENING SHOWERS AND THUNDERSTORMS WOULD BE NORTH GA WHERE OROGRAPHIC LIFT AND SUBTLE UPPER DISTURBANCES MAY PROVIDE SUFFICIENT FORCING FOR DEVELOPMENT. WILL CONTINUE TO SHOW ISOLATED THUNDER FOR NORTH GA THIS AFTERNOON AND EVENING... AND ONCE AGAIN ON TUESDAY. OTHERWISE... MODELS ARE IN GOOD AGREEMENT WITH SURFACE AND UPPER LEVEL RIDGE BUILDING OVER THE STATE TUE-WED IN RESPONSE TO DEEPENING LOW PRESSURE OVER THE PLAINS THROUGH MID WEEK. AS A RESULT... EXPECT SLIGHTLY LESS OF A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS NORTH GA TUE AFTERNOON/EVENING... AND NIL CHANCE ON WEDNESDAY. AS FOR TEMPS... LEANED SLIGHTLY COOLER THAN GUIDANCE FOR LOWS TONIGHT WITH LIGHT WINDS UNDER MOSTLY CLEAR SKIES INITIALLY... ALTHO EXPECT THE SSE FLOW TO ADVECT SOME LOW LEVEL STRATUS NORTHWARD FROM ATLANTIC AND GULF TOWARD MORNING. THEN WENT WITH A MAV AND MET BLEND FOR THE REMAINING PERIODS AS A WARMING TREND CONTINUES IN RESPONSE BUILDING HIGH PRESSURE AND CONTINUED DRY CONDITIONS. 39 LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... NO MAJOR CHANGES MADE TO THE EXTENDED FORECAST. THINGS CONTINUE TO LOOK LIKE A MORE SUMMER- LIKE PATTERN DEVELOPING THIS WEEK. MODELS IN GOOD AGREEMENT IN BUILDING THE H5 RIDGE OVER THE CWA THROUGH THE UPCOMING WEEKEND. HIGH PRESSURE AT THE SURFACE WILL BE BECOME CENTERED OFF THE EAST COAST. THIS WILL BRING AN EAST TO SOUTHEAST SURFACE FLOW TO THE CWA THEREBY INCREASING HUMIDITIES THROUGH THE WEEK. THERE COULD BE A FEW ISOLATED AFTERNOON/EVENING THUNDERSTORMS DEVELOPING EACH AFTERNOON...BUT WITH THE H5 RIDGE HOLDING FIRM OVER THE CWA...THIS RISK SHOULD BE LESS THAN 20 PERCENT. A COLD FRONT WILL MOVE INTO THE TENNESSEE VALLEY BY NEXT WEEKEND AS THE UPPER RIDGE WEAKENS. AT THE SAME TIME A SHORT WAVE MOVES INTO THE OHIO AND TENNESSEE VALLEYS. THIS WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS MAINLY TO NORTH GA SUNDAY AND MONDAY. 01/17 && .AVIATION... 06Z UPDATE... CONTINUED VFR THROUGH THE PERIOD. THERE MAY BE SOME BRIEF MVFR FOG AT AHN/MCN BUT FOR NOW HAVE KEPT 6SM BR. SE WINDS THROUGH THE PERIOD BELOW 5K THIS MORNING...5-10KT THIS AFTERNOON...BACK BELOW 5KT TONIGHT ALL BUT ATL. MAY SEE FEW AFTERNOON CU 5-7KFT BUT FOR THE MOST PART ANY CLOUDS WILL BE MID-LEVEL. //ATL CONFIDENCE...06Z UPDATE... HIGH ON ALL ELEMENTS. TDP && .PRELIMINARY POINT TEMPS/POPS... ATHENS 87 60 87 63 / 0 0 5 10 ATLANTA 86 65 86 66 / 0 0 5 10 BLAIRSVILLE 83 57 82 58 / 5 5 5 10 CARTERSVILLE 87 62 88 63 / 0 0 5 10 COLUMBUS 88 64 89 67 / 0 0 5 10 GAINESVILLE 87 61 85 63 / 5 5 5 10 MACON 88 62 89 64 / 0 0 5 10 ROME 88 62 90 62 / 5 5 5 10 PEACHTREE CITY 86 59 86 62 / 0 0 5 10 VIDALIA 89 64 88 66 / 0 0 5 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
324 PM CDT TUE MAY 28 2013 .DISCUSSION... ISSUED 300 PM CDT TUE MAY 28 2013 COMPLICATED WEATHER PATTERN IN GENERAL MADE MORE COMPLICATED IN THE MODELS WITH A STRUGGLE WITH THE PATTERN SHIFT OVERALL. HOWEVER...FOR ALL THE NUANCES WITH THE WAVES MOVING THROUGH THE FORECAST AREA...THE ONE AGREED UPON PORTION IN ALL THE OPERATIONAL MODELS IS THAT CENTRAL ILLINOIS WILL BE RATHER WET THROUGH THE END OF THE WEEK. WARM FRONT WELL TO THE NORTH OF THE CWA...LEAVING ILX IN THE WARM SECTOR WITH WARM TEMPS AND DEWPOINTS IN A RATHER MUGGY AIRMASS. THIS WARMTH AND MOISTURE WILL HELP TO FUEL ANY MCS REMNANTS/BOUNDARIES THAT MOVE INTO THE FA...IN ADDITION TO THE OVERALL FRONT SCHEDULED TO MOVE INTO THE MIDWEST AT MIDWEEK. WITH SWRLY FLOW ALOFT...THE FRONT IS GOING TO LOSE ITS FORWARD MOMENTUM...SLOW MOVING...AND SLOW TO EXIT. AS A RESULT...ANY WAVES THAT EJECT OUT OF THE SW AND ALONG THE BOUNDARY WILL RESULT IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. HEAVY RAIN IS LIKELY INVOF WHEREVER THE FRONT LANDS...WHICH WILL NOT ONLY BE DIFFICULT TO PIN...FRONT WILL ALSO END UP GETTING INFLUENCED GREATLY BY MESOSCALE INFLUENCES/COLD POOLS/OUTFLOWS AS WELL. WITH GROUND ALREADY VERY SATURATED FROM PREVIOUS RAINS...THE FLASH FLOODING THREAT MAY GET A BREAK TOMORROW FOR PORTIONS OF CENTRAL ILLINOIS...BUT IT WILL BE BACK BY THURSDAY. SHORT TERM...TONIGHT THROUGH TOMORROW... SCATTERED THUNDERSTORMS STILL POSSIBLE THROUGH THE EVENING WITH CONVECTIVE INITIATION LIKELY TO THE WEST IN NRN MO JUST ACROSS THE MISS RIVER VALLEY. BOTH RUC AND NMM/WRF KEEPING SOME ACTIVITY...THOUGH THE RUC/RAP IS ACTUALLY CONFINING MUCH OF THE ACTIVITY TO THE NORTH. THE 4KM WRF/NMM DEVELOPS MORE OF A LINEAR COMPLEX THAT EVENTUALLY MOVES THROUGH THE FA TO THE SE AND WEAKENS AS IT TRAVERSES THE CWA. SHOWER THREAT FINALLY DIMINISHES BRIEFLY FOR WEDNESDAY...THOUGH THE THREAT OF ANY INTERACTION WITH THE WARM FRONT TO THE NORTH RESULTS IN POPS ACROSS THE NRN TIER OF THE STATE. WARM TEMPS...SOUTHERLY WINDS...AND ABUNDANT MOISTURE IN THE BOUNDARY LAYER WILL PUSH HEAT INDEX VALUES INTO THE UPPER 80S/NEAR 90. WINDS WILL BE RATHER BREEZY AND HELP TO COUNTER SOME OF THE EFFECTS...THOUGH CAUTION SHOULD BE USED BY ANYONE OUTDOORS TOMORROW. LONG TERM...THURSDAY THROUGH MONDAY... THE WESTERN TROF DIGS IN...AMPLIFYING THE WAVE PATTERN OVER THE CONUS AND LEAVING THE UPPER MIDWEST IN SWRLY FLOW...THROUGH THURSDAY...WITH WARM TEMPS YET AGAIN ON THURSDAY. TEMPS IN THE NW SHOULD BE SOMEWHAT DAMPENED HOWEVER...BY CLOUD COVER FROM APPROACHING BOUNDARY. IN ADDITION...DIURNAL CURVE WILL LIKELY BE SHATTERED BY THE CONVECTIVE ACTIVITY RUINING THE STEADY CLIMB OF TEMPERATURES IN ANY ONE SPOT AHEAD OF THAT BOUNDARY. FORECAST CONFIDENCE ABOUT DETAILS COMPLICATED WITH THE ELONGATED TROF IN THE ECMWF/NAM IS PROVIDING A SLIGHTLY DIFFERENT SOLUTION WITH THE SFC SYSTEM THAN THE NAM. THAT BEING SAID...THE ECMWF IS LOOKING A BIT MORE LIKE THE GFS IN THE 12Z RUN. THOUGH EVERYONE IS IN AGREEMENT ABOUT ENTERING A PROLONGED PERIOD OF PRECIP THROUGH DAY 5...THE DIFFERENCES IN THE MODELS WILL IMPACT THE DYNAMICS AND ASSOCIATED SEVERE WEATHER THREAT. FORECASTING ONSET OF THE HEAVIEST PRECIP ALONG THE APPROACHING FRONT. IN SUMMARY...THE RAIN IS NOT OVER AS LONG AS THAT FRONT WITH THE NEXT SYSTEM GETS SLOWED BY PARALLEL FLOW ALOFT. HJS && .AVIATION... ISSUED 1244 PM CDT TUE MAY 28 2013 CONVECTION FROM EARLY THIS MORNING HAS CLEARED THE CENTRAL ILLINOIS TERMINALS...LEAVING BEHIND A 4000-8000FT MID-LEVEL OVERCAST. CLOUDS WILL CONTINUE TO THIN THIS AFTERNOON...ALLOWING THE ATMOSPHERE TO DESTABILIZE AND SCATTERED THUNDERSTORMS TO DEVELOP. STILL SOME UNCERTAINTIES AS TO EXACTLY WHERE STORMS WILL FIRE...BUT MOST LIKELY SCENARIO PLACES THEM FURTHER NORTH/NORTHWEST NEAR STATIONARY FRONTAL BOUNDARY ACROSS IOWA INTO FAR NORTHERN ILLINOIS. HRRR HAS BEEN CONSISTENTLY SHOWING CONVECTION DEVELOPING SOUTH OF THE FRONT FROM NORTHERN MISSOURI E/NE TO THE I-80 CORRIDOR AFTER 20Z FOR THE PAST SEVERAL RUNS. STORMS ARE EXPECTED TO GRADUALLY DEVELOP/SHIFT FURTHER EASTWARD ACROSS NORTH-CENTRAL ILLINOIS THIS EVENING. HAVE THEREFORE INCLUDED VCTS AT KPIA AND KBMI BETWEEN 00Z AND 05Z. FURTHER SOUTH AT THE REMAINING TAF SITES...HAVE FEATURED THUNDER BETWEEN 02Z AND 09Z. WINDS WILL BE QUITE STRONG/GUSTY THIS AFTERNOON...AS LOW-LEVEL JET MIXES TO THE SURFACE. SOUTHERLY WINDS WILL GUST TO BETWEEN 25 AND 30KT AT TIMES THROUGH THE AFTERNOON...BEFORE DIMINISHING TO BETWEEN 10 AND 15KT TONIGHT. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR ILZ027>031- 036>038-040>043-047>053-061. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1245 PM CDT TUE MAY 28 2013 .DISCUSSION... ISSUED 1044 AM CDT TUE MAY 28 2013 THUNDERSTORM COMPLEX THAT PUSHED INTO WEST-CENTRAL ILLINOIS EARLY THIS MORNING HAS WEAKENED CONSIDERABLY OVER THE PAST COUPLE OF HOURS. 15Z/10AM RADAR MOSAIC SHOWS LINGERING CONVECTION JUST SOUTH OF THE KILX CWA IN THE SAINT LOUIS METRO AREA. FURTHER NORTH...ONLY A FEW SCATTERED SHOWERS LINGER EAST OF I-55. THANKS TO EXTENSIVE CLOUD COVER...LAPS DATA SHOWS A STABLE LOW-LEVEL AIRMASS IN PLACE...WITH CAPE VALUES OF LESS THAN 500J/KG. BREAKS IN THE OVERCAST UPSTREAM OVER IOWA/MISSOURI WILL WORK EASTWARD OVER THE NEXT FEW HOURS...WITH PARTLY TO MOSTLY CLOUDY SKIES EXPECTED THIS AFTERNOON. PARTIAL SUNSHINE WILL ALLOW THE AIRMASS TO DESTABILIZE THIS AFTERNOON...WITH SCATTERED THUNDERSTORMS RE-DEVELOPING. CONVECTION SHOULD BE MOST NUMEROUS FURTHER NORTH CLOSER TO SYNOPTIC FRONTAL BOUNDARY DRAPED ACROSS IOWA INTO NORTHERN ILLINOIS. AS SUCH...WILL INCLUDE HIGH CHANCE POPS ACROSS THE FAR NORTHERN CWA THIS AFTERNOON...TAPERING DOWN TO JUST SLIGHT CHANCE POPS ALONG/SOUTH OF I-70. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH ANY STORMS THAT DEVELOP...SO FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH 7 PM FOR ALL LOCATIONS ALONG/WEST OF A BLOOMINGTON TO SHELBYVILLE LINE. ZONE UPDATE WILL BE ISSUED SHORTLY. && .AVIATION... ISSUED 1244 PM CDT TUE MAY 28 2013 CONVECTION FROM EARLY THIS MORNING HAS CLEARED THE CENTRAL ILLINOIS TERMINALS...LEAVING BEHIND A 4000-8000FT MID-LEVEL OVERCAST. CLOUDS WILL CONTINUE TO THIN THIS AFTERNOON...ALLOWING THE ATMOSPHERE TO DESTABILIZE AND SCATTERED THUNDERSTORMS TO DEVELOP. STILL SOME UNCERTAINTIES AS TO EXACTLY WHERE STORMS WILL FIRE...BUT MOST LIKELY SCENARIO PLACES THEM FURTHER NORTH/NORTHWEST NEAR STATIONARY FRONTAL BOUNDARY ACROSS IOWA INTO FAR NORTHERN ILLINOIS. HRRR HAS BEEN CONSISTENTLY SHOWING CONVECTION DEVELOPING SOUTH OF THE FRONT FROM NORTHERN MISSOURI E/NE TO THE I-80 CORRIDOR AFTER 20Z FOR THE PAST SEVERAL RUNS. STORMS ARE EXPECTED TO GRADUALLY DEVELOP/SHIFT FURTHER EASTWARD ACROSS NORTH-CENTRAL ILLINOIS THIS EVENING. HAVE THEREFORE INCLUDED VCTS AT KPIA AND KBMI BETWEEN 00Z AND 05Z. FURTHER SOUTH AT THE REMAINING TAF SITES...HAVE FEATURED THUNDER BETWEEN 02Z AND 09Z. WINDS WILL BE QUITE STRONG/GUSTY THIS AFTERNOON...AS LOW-LEVEL JET MIXES TO THE SURFACE. SOUTHERLY WINDS WILL GUST TO BETWEEN 25 AND 30KT AT TIMES THROUGH THE AFTERNOON...BEFORE DIMINISHING TO BETWEEN 10 AND 15KT TONIGHT. BARNES && .PREV DISCUSSION... ISSUED 321 AM CDT TUE MAY 28 2013 SHORT TERM...TODAY THROUGH WEDNESDAY WARM FRONT AT 07Z HAD LIFTED NORTH OF THE I-80 CORRIDOR WITH S/SE WINDS SOUTH OF THE BOUNDARY ADVECTING LOW 60S DEWPOINTS INTO THE CWA. IMPRESSIVE FORWARD PROPAGATING MCS MOVING INTO NE MO HAD A LARGE AREA OF COLD CLOUD TOPS AT -60C OR LESS PAST FEW HOURS. THIS MCS WAS BEING MAINTAINED BY A 55-65 KT SW 850MB JET WHICH TAPPED INTO A 15-17C DEWPOINT POOL OVER THE PLAINS. FIRST FORECAST ISSUE WILL BE THE IMPACT OF THIS MCS ON THE CWA THIS MORNING. AWIPS DISTANCE/SPEED TOOL TAKES THE LEADING EDGE INTO THE FAR WESTERN CWA JUST BEFORE 10Z/5AM. LATEST HRRR AND 4KM NSSL WRF SEEMED TO HAVE THE BEST HANDLE ON THIS SYSTEM AND BOTH SHOW CONVECTION MAINTAINING INTENSITY AT LEAST THROUGH THE WESTERN HALF OF THE CWA THROUGH 12-13Z. STRONG 850MB MOISTURE TRANSPORT FEED IN FROM THE SW TO KEEP HEAVY RAIN RATES OF 1.5 IN/HR WHICH COULD LEAD TO ANOTHER ROUND OF FLASH FLOODING...ESPECIALLY IF FORWARD SPEED SLOWS OR TRAINING DEVELOPS. WILL NEED TO EXTEND THE CURRENT FLASH FLOOD WATCH THROUGH 00Z. SEVERE WIND GUSTS WILL ALSO NEED TO BE MONITORED FOR THE NEXT FEW HOURS...AS LATEST SPC MESO-ANALYSIS SHOWS AN AREA OF 1K DCAPE SHIFTING INTO WEST CENTRAL IL. KIRK IN NE MO RECENTLY REPORTED A GUST OF 57 KTS ON THE LEADING EDGE OF THIS LINE. SECONDARY FORECAST CONCERN IS POSSIBLE SVR CONVECTION THIS AFTERNOON FORMING ALONG REMNANT MESOSCALE BOUNDARIES. FORECAST SOUNDINGS SHOW LITTLE IN THE WAY OF CINH...AND WITH AFTERNOON HEATING SFC BASED CAPES OF 2000-2500 J/KG AND 40KTS 0-6KM BULK SHEAR WOULD SUPPORT SEVERE STORMS. OF COURSE QUESTION MARKS REVOLVE AROUND STABILIZING EFFECTS OF MORNING MCS AND RECOVERY. SPC HAS EXPANDED DAY 1 SLIGHT RISK TO INCLUDE AREAS NORTH OF I-70. FOR TONIGHT...POTENTIAL IS THERE FOR ANOTHER MCS TO FORM NEAR THE IA/MO BORDER REGION AND SHIFT EAST AFFECTING MAINLY THE NORTHERN CWA INTO EARLY WEDNESDAY MORNING. BY WEDNESDAY UPPER LEVEL RIDGING TEMPORARILY BUILDS OVER THE AREA SHIFTING THE MAIN STORM PATH NORTH. LOW PRESSURE DEVELOPING OVER THE PLAINS WILL TIGHTEN UP THE MSLP GRADIENT CAUSING SOUTH WINDS TO GUST AROUND 30 MPH. THIS COMBINED WITH SOME SUN SHOULD PRODUCE A VERY WARM DAY WITH HIGHS IN THE MID/UPPER 80S. LONG TERM...THURSDAY THROUGH MONDAY THURSDAY AND FRIDAY...CLOSED UPPER LOW SHIFTING INTO THE NORTHERN PLAINS BRINGS A DIFLUENT SOUTHWEST MID LEVEL FLOW OVER THE MIDWEST. LEAD SHORTWAVES RIPPLING THROUGH IN THIS FLOW WILL ACT ON A HIGH P/W ATMOSPHERE FOR SEVERAL ROUND OF SHOWERS AND STORMS. LOCALLY HEAVY RAIN AND SEVERE STORMS WILL BE POSSIBLE. BY SATURDAY THE UPPER LOW BEGINS TO OPEN UP AND SHIFT SOUTHEAST...HELPING EASE A COLD FRONT INTO THE AREA. MEDIUM RANGE MODELS SHOW THIS TO BE A SLOW PROCESS...WITH MULTIPLE ROUNDS OF THUNDERSTORMS LIKELY AS THE FRONT DRIFTS ACROSS THE CWA SATURDAY AND SATURDAY NIGHT. AGAIN...SYNOPTIC SETUP FAVORS MORE LOCALLY HEAVY RAIN AND STRONG TO SEVERE CONVECTION. SUNDAY AND MONDAY...THE UPPER TROF SHIFTS ACROSS THE MIDWEST AND GREAT LAKES...BRINGING A RETURN TO COOLER AND DRIER WEATHER. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031- 036>038-040>043-047>053-061. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1044 AM CDT TUE MAY 28 2013 .DISCUSSION... ISSUED 1044 AM CDT TUE MAY 28 2013 THUNDERSTORM COMPLEX THAT PUSHED INTO WEST-CENTRAL ILLINOIS EARLY THIS MORNING HAS WEAKENED CONSIDERABLY OVER THE PAST COUPLE OF HOURS. 15Z/10AM RADAR MOSAIC SHOWS LINGERING CONVECTION JUST SOUTH OF THE KILX CWA IN THE SAINT LOUIS METRO AREA. FURTHER NORTH...ONLY A FEW SCATTERED SHOWERS LINGER EAST OF I-55. THANKS TO EXTENSIVE CLOUD COVER...LAPS DATA SHOWS A STABLE LOW-LEVEL AIRMASS IN PLACE...WITH CAPE VALUES OF LESS THAN 500J/KG. BREAKS IN THE OVERCAST UPSTREAM OVER IOWA/MISSOURI WILL WORK EASTWARD OVER THE NEXT FEW HOURS...WITH PARTLY TO MOSTLY CLOUDY SKIES EXPECTED THIS AFTERNOON. PARTIAL SUNSHINE WILL ALLOW THE AIRMASS TO DESTABILIZE THIS AFTERNOON...WITH SCATTERED THUNDERSTORMS RE-DEVELOPING. CONVECTION SHOULD BE MOST NUMEROUS FURTHER NORTH CLOSER TO SYNOPTIC FRONTAL BOUNDARY DRAPED ACROSS IOWA INTO NORTHERN ILLINOIS. AS SUCH...WILL INCLUDE HIGH CHANCE POPS ACROSS THE FAR NORTHERN CWA THIS AFTERNOON...TAPERING DOWN TO JUST SLIGHT CHANCE POPS ALONG/SOUTH OF I-70. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH ANY STORMS THAT DEVELOP...SO FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH 7 PM FOR ALL LOCATIONS ALONG/WEST OF A BLOOMINGTON TO SHELBYVILLE LINE. ZONE UPDATE WILL BE ISSUED SHORTLY. BARNES && .AVIATION... ISSUED 645 AM CDT TUE MAY 28 2013 ONGOING CONVECTION AT 12Z WILL MOSTLY PASS ACROSS THE TERMINAL SITES BY 15Z-16Z WITH VFR CONDITIONS IN LIGHT RAIN AND ISOLATED THUNDER. A BRIEF PERIOD OF MVFR WILL BE POSSIBLE IF ANY STORM PASSES DIRECTLY OVER A TERMINAL SITE. SINCE THE WARM FRONT HAS FINALLY PUSHED NORTH OF OUR COUNTIES...WINDS WILL BE INCREASING FROM THE SOUTHWEST WITH SUSTAINED IN THE 14-18KT RANGE AND GUSTS TO 26-28KT. WINDS WILL DIMINISH THIS EVENING OUTSIDE OF THE NEXT STORM COMPLEX THAT IS EXPECTED TO MOVE THROUGH CENTRAL IL LATE THIS AFTERNOON AND THIS EVENING. WE JUST ACKNOWLEDGED THAT NEXT LINE OF STORMS WITH A VCTS...AS TIMING IS A TOUGH CALL UNTIL CONVECTIVE INITIATION IS REACHED AT SOME POINT THIS AFTERNOON. DRY CONDITIONS SHOULD RETURN BY MIDNIGHT IN ALL BUT THE FAR NORTHERN AREAS. HOWEVER...SOME LIGHT FOG MAY BEGIN TO DEVELOP IF WINDS WEAKEN BY SUNRISE ON WEDNESDAY. CONFIDENCE IS LOW THAT WINDS WILL GO LIGHT ENOUGH FOR FOG TO BECOME AN ISSUE...SO FOG WAS LEFT OFF THIS SET OF TAFS. SHIMON && .PREV DISCUSSION... ISSUED 321 AM CDT TUE MAY 28 2013 SHORT TERM...TODAY THROUGH WEDNESDAY WARM FRONT AT 07Z HAD LIFTED NORTH OF THE I-80 CORRIDOR WITH S/SE WINDS SOUTH OF THE BOUNDARY ADVECTING LOW 60S DEWPOINTS INTO THE CWA. IMPRESSIVE FORWARD PROPAGATING MCS MOVING INTO NE MO HAD A LARGE AREA OF COLD CLOUD TOPS AT -60C OR LESS PAST FEW HOURS. THIS MCS WAS BEING MAINTAINED BY A 55-65 KT SW 850MB JET WHICH TAPPED INTO A 15-17C DEWPOINT POOL OVER THE PLAINS. FIRST FORECAST ISSUE WILL BE THE IMPACT OF THIS MCS ON THE CWA THIS MORNING. AWIPS DISTANCE/SPEED TOOL TAKES THE LEADING EDGE INTO THE FAR WESTERN CWA JUST BEFORE 10Z/5AM. LATEST HRRR AND 4KM NSSL WRF SEEMED TO HAVE THE BEST HANDLE ON THIS SYSTEM AND BOTH SHOW CONVECTION MAINTAINING INTENSITY AT LEAST THROUGH THE WESTERN HALF OF THE CWA THROUGH 12-13Z. STRONG 850MB MOISTURE TRANSPORT FEED IN FROM THE SW TO KEEP HEAVY RAIN RATES OF 1.5 IN/HR WHICH COULD LEAD TO ANOTHER ROUND OF FLASH FLOODING...ESPECIALLY IF FORWARD SPEED SLOWS OR TRAINING DEVELOPS. WILL NEED TO EXTEND THE CURRENT FLASH FLOOD WATCH THROUGH 00Z. SEVERE WIND GUSTS WILL ALSO NEED TO BE MONITORED FOR THE NEXT FEW HOURS...AS LATEST SPC MESO-ANALYSIS SHOWS AN AREA OF 1K DCAPE SHIFTING INTO WEST CENTRAL IL. KIRK IN NE MO RECENTLY REPORTED A GUST OF 57 KTS ON THE LEADING EDGE OF THIS LINE. SECONDARY FORECAST CONCERN IS POSSIBLE SVR CONVECTION THIS AFTERNOON FORMING ALONG REMNANT MESOSCALE BOUNDARIES. FORECAST SOUNDINGS SHOW LITTLE IN THE WAY OF CINH...AND WITH AFTERNOON HEATING SFC BASED CAPES OF 2000-2500 J/KG AND 40KTS 0-6KM BULK SHEAR WOULD SUPPORT SEVERE STORMS. OF COURSE QUESTION MARKS REVOLVE AROUND STABILIZING EFFECTS OF MORNING MCS AND RECOVERY. SPC HAS EXPANDED DAY 1 SLIGHT RISK TO INCLUDE AREAS NORTH OF I-70. FOR TONIGHT...POTENTIAL IS THERE FOR ANOTHER MCS TO FORM NEAR THE IA/MO BORDER REGION AND SHIFT EAST AFFECTING MAINLY THE NORTHERN CWA INTO EARLY WEDNESDAY MORNING. BY WEDNESDAY UPPER LEVEL RIDGING TEMPORARILY BUILDS OVER THE AREA SHIFTING THE MAIN STORM PATH NORTH. LOW PRESSURE DEVELOPING OVER THE PLAINS WILL TIGHTEN UP THE MSLP GRADIENT CAUSING SOUTH WINDS TO GUST AROUND 30 MPH. THIS COMBINED WITH SOME SUN SHOULD PRODUCE A VERY WARM DAY WITH HIGHS IN THE MID/UPPER 80S. LONG TERM...THURSDAY THROUGH MONDAY THURSDAY AND FRIDAY...CLOSED UPPER LOW SHIFTING INTO THE NORTHERN PLAINS BRINGS A DIFLUENT SOUTHWEST MID LEVEL FLOW OVER THE MIDWEST. LEAD SHORTWAVES RIPPLING THROUGH IN THIS FLOW WILL ACT ON A HIGH P/W ATMOSPHERE FOR SEVERAL ROUND OF SHOWERS AND STORMS. LOCALLY HEAVY RAIN AND SEVERE STORMS WILL BE POSSIBLE. BY SATURDAY THE UPPER LOW BEGINS TO OPEN UP AND SHIFT SOUTHEAST...HELPING EASE A COLD FRONT INTO THE AREA. MEDIUM RANGE MODELS SHOW THIS TO BE A SLOW PROCESS...WITH MULTIPLE ROUNDS OF THUNDERSTORMS LIKELY AS THE FRONT DRIFTS ACROSS THE CWA SATURDAY AND SATURDAY NIGHT. AGAIN...SYNOPTIC SETUP FAVORS MORE LOCALLY HEAVY RAIN AND STRONG TO SEVERE CONVECTION. SUNDAY AND MONDAY...THE UPPER TROF SHIFTS ACROSS THE MIDWEST AND GREAT LAKES...BRINGING A RETURN TO COOLER AND DRIER WEATHER. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031- 036>038-040>043-047>053-061. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
645 AM CDT TUE MAY 28 2013 .DISCUSSION... ISSUED 321 AM CDT TUE MAY 28 2013 SHORT TERM...TODAY THROUGH WEDNESDAY WARM FRONT AT 07Z HAD LIFTED NORTH OF THE I-80 CORRIDOR WITH S/SE WINDS SOUTH OF THE BOUNDARY ADVECTING LOW 60S DEWPOINTS INTO THE CWA. IMPRESSIVE FORWARD PROPAGATING MCS MOVING INTO NE MO HAD A LARGE AREA OF COLD CLOUD TOPS AT -60C OR LESS PAST FEW HOURS. THIS MCS WAS BEING MAINTAINED BY A 55-65 KT SW 850MB JET WHICH TAPPED INTO A 15-17C DEWPOINT POOL OVER THE PLAINS. FIRST FORECAST ISSUE WILL BE THE IMPACT OF THIS MCS ON THE CWA THIS MORNING. AWIPS DISTANCE/SPEED TOOL TAKES THE LEADING EDGE INTO THE FAR WESTERN CWA JUST BEFORE 10Z/5AM. LATEST HRRR AND 4KM NSSL WRF SEEMED TO HAVE THE BEST HANDLE ON THIS SYSTEM AND BOTH SHOW CONVECTION MAINTAINING INTENSITY AT LEAST THROUGH THE WESTERN HALF OF THE CWA THROUGH 12-13Z. STRONG 850MB MOISTURE TRANSPORT FEED IN FROM THE SW TO KEEP HEAVY RAIN RATES OF 1.5 IN/HR WHICH COULD LEAD TO ANOTHER ROUND OF FLASH FLOODING...ESPECIALLY IF FORWARD SPEED SLOWS OR TRAINING DEVELOPS. WILL NEED TO EXTEND THE CURRENT FLASH FLOOD WATCH THROUGH 00Z. SEVERE WIND GUSTS WILL ALSO NEED TO BE MONITORED FOR THE NEXT FEW HOURS...AS LATEST SPC MESO-ANALYSIS SHOWS AN AREA OF 1K DCAPE SHIFTING INTO WEST CENTRAL IL. KIRK IN NE MO RECENTLY REPORTED A GUST OF 57 KTS ON THE LEADING EDGE OF THIS LINE. SECONDARY FORECAST CONCERN IS POSSIBLE SVR CONVECTION THIS AFTERNOON FORMING ALONG REMNANT MESOSCALE BOUNDARIES. FORECAST SOUNDINGS SHOW LITTLE IN THE WAY OF CINH...AND WITH AFTERNOON HEATING SFC BASED CAPES OF 2000-2500 J/KG AND 40KTS 0-6KM BULK SHEAR WOULD SUPPORT SEVERE STORMS. OF COURSE QUESTION MARKS REVOLVE AROUND STABILIZING EFFECTS OF MORNING MCS AND RECOVERY. SPC HAS EXPANDED DAY 1 SLIGHT RISK TO INCLUDE AREAS NORTH OF I-70. FOR TONIGHT...POTENTIAL IS THERE FOR ANOTHER MCS TO FORM NEAR THE IA/MO BORDER REGION AND SHIFT EAST AFFECTING MAINLY THE NORTHERN CWA INTO EARLY WEDNESDAY MORNING. BY WEDNESDAY UPPER LEVEL RIDGING TEMPORARILY BUILDS OVER THE AREA SHIFTING THE MAIN STORM PATH NORTH. LOW PRESSURE DEVELOPING OVER THE PLAINS WILL TIGHTEN UP THE MSLP GRADIENT CAUSING SOUTH WINDS TO GUST AROUND 30 MPH. THIS COMBINED WITH SOME SUN SHOULD PRODUCE A VERY WARM DAY WITH HIGHS IN THE MID/UPPER 80S. LONG TERM...THURSDAY THROUGH MONDAY THURSDAY AND FRIDAY...CLOSED UPPER LOW SHIFTING INTO THE NORTHERN PLAINS BRINGS A DIFLUENT SOUTHWEST MID LEVEL FLOW OVER THE MIDWEST. LEAD SHORTWAVES RIPPLING THROUGH IN THIS FLOW WILL ACT ON A HIGH P/W ATMOSPHERE FOR SEVERAL ROUND OF SHOWERS AND STORMS. LOCALLY HEAVY RAIN AND SEVERE STORMS WILL BE POSSIBLE. BY SATURDAY THE UPPER LOW BEGINS TO OPEN UP AND SHIFT SOUTHEAST...HELPING EASE A COLD FRONT INTO THE AREA. MEDIUM RANGE MODELS SHOW THIS TO BE A SLOW PROCESS...WITH MULTIPLE ROUNDS OF THUNDERSTORMS LIKELY AS THE FRONT DRIFTS ACROSS THE CWA SATURDAY AND SATURDAY NIGHT. AGAIN...SYNOPTIC SETUP FAVORS MORE LOCALLY HEAVY RAIN AND STRONG TO SEVERE CONVECTION. SUNDAY AND MONDAY...THE UPPER TROF SHIFTS ACROSS THE MIDWEST AND GREAT LAKES...BRINGING A RETURN TO COOLER AND DRIER WEATHER. 25 && .AVIATION... ISSUED 645 AM CDT TUE MAY 28 2013 ONGOING CONVECTION AT 12Z WILL MOSTLY PASS ACROSS THE TERMINAL SITES BY 15Z-16Z WITH VFR CONDITIONS IN LIGHT RAIN AND ISOLATED THUNDER. A BRIEF PERIOD OF MVFR WILL BE POSSIBLE IF ANY STORM PASSES DIRECTLY OVER A TERMINAL SITE. SINCE THE WARM FRONT HAS FINALLY PUSHED NORTH OF OUR COUNTIES...WINDS WILL BE INCREASING FROM THE SOUTHWEST WITH SUSTAINED IN THE 14-18KT RANGE AND GUSTS TO 26-28KT. WINDS WILL DIMINISH THIS EVENING OUTSIDE OF THE NEXT STORM COMPLEX THAT IS EXPECTED TO MOVE THROUGH CENTRAL IL LATE THIS AFTERNOON AND THIS EVENING. WE JUST ACKNOWLEDGED THAT NEXT LINE OF STORMS WITH A VCTS...AS TIMING IS A TOUGH CALL UNTIL CONVECTIVE INITIATION IS REACHED AT SOME POINT THIS AFTERNOON. DRY CONDITIONS SHOULD RETURN BY MIDNIGHT IN ALL BUT THE FAR NORTHERN AREAS. HOWEVER...SOME LIGHT FOG MAY BEGIN TO DEVELOP IF WINDS WEAKEN BY SUNRISE ON WEDNESDAY. CONFIDENCE IS LOW THAT WINDS WILL GO LIGHT ENOUGH FOR FOG TO BECOME AN ISSUE...SO FOG WAS LEFT OFF THIS SET OF TAFS. SHIMON && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS EVENING FOR ILZ027>031-036>038- 040>043-047>053-061. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
321 AM CDT TUE MAY 28 2013 .DISCUSSION... ISSUED 321 AM CDT TUE MAY 28 2013 SHORT TERM...TODAY THROUGH WEDNESDAY WARM FRONT AT 07Z HAD LIFTED NORTH OF THE I-80 CORRIDOR WITH S/SE WINDS SOUTH OF THE BOUNDARY ADVECTING LOW 60S DEWPOINTS INTO THE CWA. IMPRESSIVE FORWARD PROPAGATING MCS MOVING INTO NE MO HAD A LARGE AREA OF COLD CLOUD TOPS AT -60C OR LESS PAST FEW HOURS. THIS MCS WAS BEING MAINTAINED BY A 55-65 KT SW 850MB JET WHICH TAPPED INTO A 15-17C DEWPOINT POOL OVER THE PLAINS. FIRST FORECAST ISSUE WILL BE THE IMPACT OF THIS MCS ON THE CWA THIS MORNING. AWIPS DISTANCE/SPEED TOOL TAKES THE LEADING EDGE INTO THE FAR WESTERN CWA JUST BEFORE 10Z/5AM. LATEST HRRR AND 4KM NSSL WRF SEEMED TO HAVE THE BEST HANDLE ON THIS SYSTEM AND BOTH SHOW CONVECTION MAINTAINING INTENSITY AT LEAST THROUGH THE WESTERN HALF OF THE CWA THROUGH 12-13Z. STRONG 850MB MOISTURE TRANSPORT FEED IN FROM THE SW TO KEEP HEAVY RAIN RATES OF 1.5 IN/HR WHICH COULD LEAD TO ANOTHER ROUND OF FLASH FLOODING...ESPECIALLY IF FORWARD SPEED SLOWS OR TRAINING DEVELOPS. WILL NEED TO EXTEND THE CURRENT FLASH FLOOD WATCH THROUGH 00Z. SEVERE WIND GUSTS WILL ALSO NEED TO BE MONITORED FOR THE NEXT FEW HOURS...AS LATEST SPC MESOANALYSIS SHOWS AN AREA OF 1K DCAPE SHIFTING INTO WEST CENTRAL IL. KIRK IN NE MO RECENTLY REPORTED A GUST OF 57 KTS ON THE LEADING EDGE OF THIS LINE. SECONDARY FORECAST CONCERN IS POSSIBLE SVR CONVECTION THIS AFTERNOON FORMING ALONG REMNANT MESOSCALE BOUNDARIES. FORECAST SOUNDINGS SHOW LITTLE IN THE WAY OF CINH...AND WITH AFTERNOON HEATING SFC BASED CAPES OF 2000-2500 J/KG AND 40KTS 0-6KM BULK SHEAR WOULD SUPPORT SEVERE STORMS. OF COURSE QUESTION MARKS REVOLVE AROUND STABILIZING EFFECTS OF MORNING MCS AND RECOVERY. SPC HAS EXPANDED DAY 1 SLIGHT RISK TO INCLUDE AREAS NORTH OF I-70. FOR TONIGHT...POTENTIAL IS THERE FOR ANOTHER MCS TO FORM NEAR THE IA/MO BORDER REGION AND SHIFT EAST AFFECTING MAINLY THE NORTHERN CWA INTO EARLY WEDNESDAY MORNING. BY WEDNESDAY UPPER LEVEL RIDGING TEMPORARILY BUILDS OVER THE AREA SHIFTING THE MAIN STORM PATH NORTH. LOW PRESSURE DEVELOPING OVER THE PLAINS WILL TIGHTEN UP THE MSLP GRADIENT CAUSING SOUTH WINDS TO GUST AROUND 30 MPH. THIS COMBINED WITH SOME SUN SHOULD PRODUCE A VERY WARM DAY WITH HIGHS IN THE MID/UPPER 80S. LONG TERM...THURSDAY THROUGH MONDAY THURSDAY AND FRIDAY...CLOSED UPPER LOW SHIFTING INTO THE NORTHERN PLAINS BRINGS A DIFLUENT SOUTHWEST MID LEVEL FLOW OVER THE MIDWEST. LEAD SHORTWAVES RIPPLING THROUGH IN THIS FLOW WILL ACT ON A HIGH P/W ATMOSPHERE FOR SEVERAL ROUND OF SHOWERS AND STORMS. LOCALLY HEAVY RAIN AND SEVERE STORMS WILL BE POSSIBLE. BY SATURDAY THE UPPER LOW BEGINS TO OPEN UP AND SHIFT SOUTHEAST...HELPING EASE A COLD FRONT INTO THE AREA. MEDIUM RANGE MODELS SHOW THIS TO BE A SLOW PROCESS...WITH MULTIPLE ROUNDS OF THUNDERSTORMS LIKELY AS THE FRONT DRIFTS ACROSS THE CWA SATURDAY AND SATURDAY NIGHT. AGAIN...SYNOPTIC SETUP FAVORS MORE LOCALLY HEAVY RAIN AND STRONG TO SEVERE CONVECTION. SUNDAY AND MONDAY...THE UPPER TROF SHIFTS ACROSS THE MIDWEST AND GREAT LAKES...BRINGING A RETURN TO COOLER AND DRIER WEATHER. 25 && .AVIATION... ISSUED 1115 PM CDT MON MAY 27 2013 COVERAGE OF SHOWERS AND THUNDERSTORMS AND THEIR AFFECT ON CIGS AND VSBYS ACROSS OUR AREA THRU TUESDAY EVENING. ISOLATED SHOWERS WERE DEVELOPING LATE THIS EVENING ACROSS THE NORTH AS A WARM FRONT WAS DRAPPED OVER CENTRAL ILLINOIS. LARGEST AREA OF CONVECTION WAS STILL LOCATED ALONG THE MISSOURI RIVER VALLEY AND THAT COMPLEX WILL TAKE UNTIL MORNING BEFORE IT AFFECTS ANY OF OUR AREA. STILL CONCERNED ABOUT THE CONTINUED DEVELOPMENT OF ISOLATED SHOWERS ACRS OUR NORTHERN AREAS OVER THE PAST SEVERAL HOURS SO WILL INCLUDE VCTS AT KBMI AND KPIA UNTIL WE CAN ACTUALLY SEE MORE WIDESPREAD RAINS APPROACH. FURTHER SOUTH...WILL HAVE TO WAIT UNTIL THE COMPLEX OUT OVER SOUTHWEST IOWA AND NW MISSOURI TRACKS INTO WEST CENTRAL IL BETWEEN 10Z AND 13Z. HOWEVER...NOT THAT ENTIRELY CONFIDENT IT WILL HOLD TOGETHER OTHER THAN SOME STRATIFORM RAINS AND POSSIBLY SOME LOWER CIGS BUT THAT FAR OUT WILL NOT HIT THE CIGS THAT HARD. WHATEVER OCCURRS TUESDAY MORNING...SHOULD TEMPORARILY END BEFORE A RENEWED THREAT FOR SCATTERED TSRA BETWEEN 20Z AND 24Z. SFC WINDS WILL BE OUT OF THE SOUTH AT 8 TO 13 KTS TNT...AND THEN SOUTH WINDS WILL INCREASE TO 12 TO 17 KTS WITH GUSTS AS HIGH AS 25 KTS DURING THE AFTERNOON. SMITH && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS EVENING FOR ILZ027>031-036>038- 040>043-047>053-061. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
156 PM EDT TUE MAY 28 2013 .SYNOPSIS... ISSUED AT 1043 AM EDT TUE MAY 28 2013 ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE AREA THIS AFTERNOON AS A WARM FRONT LIFTS NORTH THROUGH THE REGION. A FEW OF THESE STORMS COULD BECOME STRONG TO SEVERE AS WELL AS PRODUCE SOME LOCALLY HEAVY RAINFALL. RAIN CHANCES ARE EXPECTED TO DECREASE DURING THE OVERNIGHT HOURS...MAKING FOR PARTLY CLOUDY SKIES AND DRY CONDITIONS ON THURSDAY. && .UPDATE... ISSUED AT 1110 AM EDT TUE MAY 28 2013 CONDITIONAL SEVERE WEATHER THREAT REMAINS IN PLACE FOR LATER THIS AFTERNOON. LATEST WATER VAPOR LOOP SHOWS A DECENT CONVECTIVELY ENHANCED MIDLEVEL WAVE OVER IOWA THAT IS GRADUALLY MOVING EASTWARD. SYNOPTIC SCALE UVM ASSOCIATED WITH THIS MCV WILL SPREAD OVER OUR AREA LATER THIS AFTERNOON...ENCOUNTERING A RATHER MOIST AND POTENTIALLY UNSTABLE AIRMASS LEFT IN THE WAKE OF THIS MORNINGS WARM FRONTAL PASSAGE. DEGREE OF DIURNAL INSTABILITY RECOVERY REMAINS QUESTIONABLE THOUGH. REMNANTS OF MORNING CONVECTION OVER ILLINOIS ARE ALREADY IMPINGING ON OUR WESTERN BORDER WITH ABUNDANT CLOUD COVER BLANKETING THE CWA. A FEW THIN SPOTS SEEN IN LATEST VIS IMAGERY BUT OUR CWA REMAINS STABLE SO FAR. 12Z RAP CONTINUES TO SUGGEST THIS WILL CHANGE THOUGH AS FILTERED INSOLATION COMBINES WITH GOOD WAA TO PUSH TEMPS INTO THE LOW 80S. SURFACE DEWPOINTS WAY OVERDONE BUT MODIFIED SOUNDINGS STILL SHOW MLCAPE VALUES APPROACHING 1500 J/KG OVER OUR EAST BY THE AFTERNOON. WITH 700MB WINDS APPROACHING 50 KTS...THIS WARRANTS CONTINUED THREAT...MAINLY OVER OUR NORTHEASTERN AREAS IN THE 18-00Z TIMEFRAME. MAIN HAZARD EXPECTED TO BE STRAIGHT LINE WINDS BUT DECENT LOW LEVEL SHEAR VALUES SUGGEST AN ISOLATED TORNADO CANT BE RULED OUT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM EDT TUE MAY 28 2013 WARM FRONT MOVG NORTH ACROSS THE CWA EARLY THIS MORNING IS EXPECTED TO MOVE NORTH OF THE AREA BY THIS AFTN. A COUPLE OF THUNDERSTORM CLUSTERS WERE MOVG EAST ALONG THE FRONT. FIRST SHOULD BE MOVG OUT OF ERN PORTION OF CWA AROUND 12Z WHILE UPSTREAM MCS IN IA MAY REACH THE AREA AROUND THE SAME TIME. LIKELY WILL BE SOME DIURNAL WKNG OF THIS MCS HWVR SO SOME DOUBTS REMAIN IF IT WILL REACH OUR AREA. SHRTWV RESPONSIBLE FOR THE STORMS UPSTREAM IS FCST TO MOVE ACROSS THE CWA THIS AFTN THROUGH A MODERATELY UNSTABLE AIRMASS BY THAT TIME. SOME WK CAPPING SOUTH OF THE WARM FRONT SHOULD BE OVERCOME BY FORCING ASSOCIATED WITH THIS SYSTEM... ESPECIALLY ACROSS NRN PORTION OF CWA. COMBINATION OF 30-40KT 0-6KM SHEAR AND MODERATE INSTABILITY SUGGESTS SOME OF THE STORMS COULD BE SEVERE. MODELS INDICATING ANOTHER CONVECTIVELY ENHANCED SHRTWV WILL MOVE EAST ACROSS THE UPR GRTLKS TONIGHT. THIS COMBINED WITH SOME LINGERING INSTABILITY AND CONVECTIVE OUTFLOW BOUNDARIES OVER THE AREA MAY RESULT IN TSTMS AGAIN TONIGHT WITH BEST CHANCES ACROSS THE NRN PORTION OF CWA CLOSER TO WARM FRONT AND SHRTWV FORCING. DESPITE EXPECTED CONSIDERABLE CLOUDINESS TODAY... FAIRLY STRONG GRADIENT MIXING SHOULD ALLOW HIGHS TO REACH THE L80S OVER MOST OF THE CWA WITH CONTD S-SW FLOW TONIGHT RESULTING IN MINS ONLY IN THE M-U60S. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 420 AM EDT TUE MAY 28 2013 ONGOING CONVECTION MAY BE LINGERING ALONG MODIFIED FRONTAL OR OUTFLOW BOUNDARIES OVER PORTIONS OF THE FCST AREA AT THE START OF THE PERIOD. FOR NOW...LEFT A LOW CHANCE FOR STORMS OVER NORTHERN AREAS. THE UPSTREAM TROF WILL AMPLIFY WEDNESDAY...CAUSING LOW LEVEL FLOW TO INCREASE AND THE BEST LOW LEVEL THETA E CONVERGENCE TO SHIFT NORTH OF THE FCST AREA BY WEDNESDAY AFTERNOON. KEPT HIGHS IN THE MID 80S WEDNESDAY THROUGH FRIDAY SUPPORTED BY 850 MB TEMPS OF 15C TO 17C. THE ECMWF HAS TRENDED MORE AMPLIFIED WITH A TROF BECOMING POSITIVELY TILTED BY SATURDAY. THERE WILL PROBABLY BE TWO ROUNDS OF CONVECTION...THE FIRST AS A SHORT WAVE EJECTS NORTHEAST LATE THURSDAY OR THURSDAY NIGHT. CONCERN FOR SEVERE STORM POTENTIAL GIVEN JET ENERGY RACING SOUTHEAST TOWARD THE AREA. THE SECOND ROUND OF CONVECTION SHOULD OCCUR AS THE UPPER LEVEL TROF LIFTS NORTHEAST ACCOMPANIED BY A COLD FRONT EARLY THIS WEEKEND. HAVE BEEN TRENDING FASTER WITH THE ARRIVAL OF STORMS LATE THIS WEEK GIVEN THE ARRIVAL OF THE INITIAL SHORT WAVE. WPC DAY 4/5 SUPPORTS 1 TO 2.5 INCHES OF RAIN LATE THIS WEEK GIVEN MOISTURE STREAMING INTO THE AREA AHEAD OF THE UPPER TROF. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 155 PM EDT TUE MAY 28 2013 DIURNAL INSTABILITY RECOVERY WAS TOO SLOW TO CAPITALIZE ON OLD MCV CURRENTLY MOVING THROUGH MICHIGAN AND JUST A FEW ISOLATED SPRINKLES REMAIN OVER OUR CWA AT THE MOMENT. EXPECT THIS WILL CONTINUE FOR THE NEXT FEW HOURS WITH SOME ENHANCED LOW LEVEL MOISTURE BRINGING MVFR CEILINGS TO KSBN IN ITS WAKE. CONVECTION CHANCES WILL THEREFORE DEPEND ON NEXT WAVE CURRENTLY PRODUCING PRECIP OVER SOUTHERN ILLINOIS...NOT SLATED TO ARRIVE UNTIL LATER THIS EVENING. EXPECT PERIODS OF SHOWERS AND THUNDERSTORMS OVERNIGHT BUT CONFIDENCE IN EXACT PLACEMENT AND TIMING REMAINS VERY LOW. CEILINGS SHOULD REMAIN VFR THOUGH WITH ONLY BRIEF VIS REDUCTIONS IN HEAVIER PRECIP. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...AGD SYNOPSIS...KG SHORT TERM...JT LONG TERM...SKIPPER AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1110 AM EDT TUE MAY 28 2013 .SYNOPSIS... ISSUED AT 1043 AM EDT TUE MAY 28 2013 ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE AREA THIS AFTERNOON AS A WARM FRONT LIFTS NORTH THROUGH THE REGION. A FEW OF THESE STORMS COULD BECOME STRONG TO SEVERE AS WELL AS PRODUCE SOME LOCALLY HEAVY RAINFALL. RAIN CHANCES ARE EXPECTED TO DECREASE DURING THE OVERNIGHT HOURS...MAKING FOR PARTLY CLOUDY SKIES AND DRY CONDITIONS ON THURSDAY. && .UPDATE... ISSUED AT 1110 AM EDT TUE MAY 28 2013 CONDITIONAL SEVERE WEATHER THREAT REMAINS IN PLACE FOR LATER THIS AFTERNOON. LATEST WATER VAPOR LOOP SHOWS A DECENT CONVECTIVELY ENHANCED MIDLEVEL WAVE OVER IOWA THAT IS GRADUALLY MOVING EASTWARD. SYNOPTIC SCALE UVM ASSOCIATED WITH THIS MCV WILL SPREAD OVER OUR AREA LATER THIS AFTERNOON...ENCOUNTERING A RATHER MOIST AND POTENTIALLY UNSTABLE AIRMASS LEFT IN THE WAKE OF THIS MORNINGS WARM FRONTAL PASSAGE. DEGREE OF DIURNAL INSTABILITY RECOVERY REMAINS QUESTIONABLE THOUGH. REMNANTS OF MORNING CONVECTION OVER ILLINOIS ARE ALREADY IMPINGING ON OUR WESTERN BORDER WITH ABUNDANT CLOUD COVER BLANKETING THE CWA. A FEW THIN SPOTS SEEN IN LATEST VIS IMAGERY BUT OUR CWA REMAINS STABLE SO FAR. 12Z RAP CONTINUES TO SUGGEST THIS WILL CHANGE THOUGH AS FILTERED INSOLATION COMBINES WITH GOOD WAA TO PUSH TEMPS INTO THE LOW 80S. SURFACE DEWPOINTS WAY OVERDONE BUT MODIFIED SOUNDINGS STILL SHOW MLCAPE VALUES APPROACHING 1500 J/KG OVER OUR EAST BY THE AFTERNOON. WITH 700MB WINDS APPROACHING 50 KTS...THIS WARRANTS CONTINUED THREAT...MAINLY OVER OUR NORTHEASTERN AREAS IN THE 18-00Z TIMEFRAME. MAIN HAZARD EXPECTED TO BE STRAIGHT LINE WINDS BUT DECENT LOW LEVEL SHEAR VALUES SUGGEST AN ISOLATED TORNADO CANT BE RULED OUT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM EDT TUE MAY 28 2013 WARM FRONT MOVG NORTH ACROSS THE CWA EARLY THIS MORNING IS EXPECTED TO MOVE NORTH OF THE AREA BY THIS AFTN. A COUPLE OF THUNDERSTORM CLUSTERS WERE MOVG EAST ALONG THE FRONT. FIRST SHOULD BE MOVG OUT OF ERN PORTION OF CWA AROUND 12Z WHILE UPSTREAM MCS IN IA MAY REACH THE AREA AROUND THE SAME TIME. LIKELY WILL BE SOME DIURNAL WKNG OF THIS MCS HWVR SO SOME DOUBTS REMAIN IF IT WILL REACH OUR AREA. SHRTWV RESPONSIBLE FOR THE STORMS UPSTREAM IS FCST TO MOVE ACROSS THE CWA THIS AFTN THROUGH A MODERATELY UNSTABLE AIRMASS BY THAT TIME. SOME WK CAPPING SOUTH OF THE WARM FRONT SHOULD BE OVERCOME BY FORCING ASSOCIATED WITH THIS SYSTEM... ESPECIALLY ACROSS NRN PORTION OF CWA. COMBINATION OF 30-40KT 0-6KM SHEAR AND MODERATE INSTABILITY SUGGESTS SOME OF THE STORMS COULD BE SEVERE. MODELS INDICATING ANOTHER CONVECTIVELY ENHANCED SHRTWV WILL MOVE EAST ACROSS THE UPR GRTLKS TONIGHT. THIS COMBINED WITH SOME LINGERING INSTABILITY AND CONVECTIVE OUTFLOW BOUNDARIES OVER THE AREA MAY RESULT IN TSTMS AGAIN TONIGHT WITH BEST CHANCES ACROSS THE NRN PORTION OF CWA CLOSER TO WARM FRONT AND SHRTWV FORCING. DESPITE EXPECTED CONSIDERABLE CLOUDINESS TODAY... FAIRLY STRONG GRADIENT MIXING SHOULD ALLOW HIGHS TO REACH THE L80S OVER MOST OF THE CWA WITH CONTD S-SW FLOW TONIGHT RESULTING IN MINS ONLY IN THE M-U60S. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 420 AM EDT TUE MAY 28 2013 ONGOING CONVECTION MAY BE LINGERING ALONG MODIFIED FRONTAL OR OUTFLOW BOUNDARIES OVER PORTIONS OF THE FCST AREA AT THE START OF THE PERIOD. FOR NOW...LEFT A LOW CHANCE FOR STORMS OVER NORTHERN AREAS. THE UPSTREAM TROF WILL AMPLIFY WEDNESDAY...CAUSING LOW LEVEL FLOW TO INCREASE AND THE BEST LOW LEVEL THETA E CONVERGENCE TO SHIFT NORTH OF THE FCST AREA BY WEDNESDAY AFTERNOON. KEPT HIGHS IN THE MID 80S WEDNESDAY THROUGH FRIDAY SUPPORTED BY 850 MB TEMPS OF 15C TO 17C. THE ECMWF HAS TRENDED MORE AMPLIFIED WITH A TROF BECOMING POSITIVELY TILTED BY SATURDAY. THERE WILL PROBABLY BE TWO ROUNDS OF CONVECTION...THE FIRST AS A SHORT WAVE EJECTS NORTHEAST LATE THURSDAY OR THURSDAY NIGHT. CONCERN FOR SEVERE STORM POTENTIAL GIVEN JET ENERGY RACING SOUTHEAST TOWARD THE AREA. THE SECOND ROUND OF CONVECTION SHOULD OCCUR AS THE UPPER LEVEL TROF LIFTS NORTHEAST ACCOMPANIED BY A COLD FRONT EARLY THIS WEEKEND. HAVE BEEN TRENDING FASTER WITH THE ARRIVAL OF STORMS LATE THIS WEEK GIVEN THE ARRIVAL OF THE INITIAL SHORT WAVE. WPC DAY 4/5 SUPPORTS 1 TO 2.5 INCHES OF RAIN LATE THIS WEEK GIVEN MOISTURE STREAMING INTO THE AREA AHEAD OF THE UPPER TROF. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 640 AM EDT TUE MAY 28 2013 GENERALLY VFR CONDITIONS EXPECTED ACROSS NRN INDIANA THIS MORNING AS MCS MOVG OUT OF NE INDIANA. UPSTREAM MCS OVER WRN IL WAS WKNG AS STRONGER FORCING APPEARS TO BE SHIFTING NORTH INTO SRN WI AND BETTER INSTABILITY TO THE SW OVER MO. JUST FCST TEMPO -SHRA AT SBN WITH MINIMAL IMPACT ASSOCIATED WITH THIS FEATURE THIS MORNING. AMDAR SOUNDING FROM FWA EARLY THIS MORNING SHOWING RATHER STRONG SWLY FLOW ALOFT WHICH SHOULD MIX DOWN TO SFC RESULTING IN 15-25KT WINDS BY LATE MORNING. SCT TS EXPECTED TO DVLP OVER NRN INDIANA THIS AFTN AS AIRMASS DESTABILIZES AND WK SHRTWV CURRENTLY OVER IA MOVES ENE ACROSS NRN INDIANA. CONTD WITH A TEMPO TS AT BOTH TERMINALS AS THIS SYSTEM MOVES THROUGH IN THE AFTN. TS ALSO PSBL IN THE AREA TONIGHT BUT KEPT OUT OF TAFS ATTM DUE TO CONSIDERABLE UNCERTAINTY. EXPECT THERE WILL BE SUFFICIENT MIXING OVERNIGHT TO PREVENT BR FROM FORMING DESPITE MOIST AIRMASS IN PLACE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...AGD SYNOPSIS...KG SHORT TERM...JT LONG TERM...SKIPPER AVIATION...JT VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS PADUCAH KY
553 AM CDT TUE MAY 28 2013 .UPDATE... ISSUED AT 553 AM CDT TUE MAY 28 2013 RENEWED CONVECTIVE ACTIVITY ACROSS SOUTH CENTRAL MISSOURI HAS REQUIRED A REVISION IN THE NEAR TERM /TODAY/ FORECAST TO ACCOUNT FOR THE PROPAGATION OF THE BROKEN CONVECTIVE LINE INTO THE WFO PAH FORECAST AREA THIS MORNING. THE LATEST RUNS OF THE 3KM HRRR AND 12KM NAM-WRF SUGGEST SOME SCATTERED SHOWER AND THUNDERSTORM ACTIVITY OVER PARTS OF SOUTHEAST MISSOURI AND SOUTHWEST ILLINOIS. THE PREVIOUSLY MENTIONED POTENTIAL FOR ISOLATED CONVECTION OVER THE PENNYRILE ALSO SEEMS MORE REASONABLE AS WELL. CLOUD COVER...WINDS...TEMPERATURES AND DEWPOINTS HAVE ALSO BEEN MODIFIED TO ACCOUNT FOR THE STORM SCALE ACTIVITY THIS MORNING AND INTO THIS AFTERNOON. THE CLOUD COVER ALONE WILL LIKELY SHAVE MAX TEMPERATURES DOWN 1-2 DEGREES FROM PREVIOUSLY FORECAST HIGHS WITH THE ORIGINAL PACKAGE. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 304 AM CDT TUE MAY 28 2013 THE MESOSCALE CONVECTIVE SYSTEM OVER NORTHWEST/NORTH CENTRAL MO OVERNIGHT SHOULD EVENTUALLY DIMINISH BEFORE IT REACHES THE SOUTHERN IL/SOUTHEAST MISSOURI BORDER COUNTIES LATER THIS MORNING. THIS IS CONSISTENT WITH EARLIER RUNS OF THE HIGH RESOLUTION MODELS SUCH AS THE 3KM HRRR AND THE 13KM RAP GUIDANCE. PREVIOUSLY INTRODUCED /WITH THE MONDAY MORNING FORECAST PACKAGE/ SOME CHANCE POPS/WEATHER IN THE EXTREME SOUTHEAST PENNYRILE THIS AFTERNOON...BUT THE SIGNAL HAS NOT BEEN CONSISTENT ENOUGH TO WARRANT A MENTION WITH THIS PACKAGE. DAYSHIFT WILL STILL NEED TO WATCH FOR THIS CONVECTIVE POTENTIAL. FOR THE MOST PART DRY CONDITIONS SHOULD PREVAIL WITH CAPPING ALOFT THROUGH MOST OF THE DAYTIME HOURS ON WEDNESDAY. THE MID-ATLANTIC/SOUTHEAST U.S. RIDGE BRIEFLY HOLDS IN PLACE WHILE THE SURFACE AND UPPER LEVEL FLOW BECOME MORE SOUTH/SOUTHWEST IN ORIENTATION STARTING LATE TONIGHT INTO WEDNESDAY WITH AN APPROACHING LOW. THE PRESSURE/HEIGHT GRADIENT TIGHTENS UP FROM THE WEST AS AN NORTHWESTWARD TILTED SURFACE-UPPER LEVEL LOW MOVES OUT OF THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS /MAINLY IN THE THE DAKOTAS/ BY WEDNESDAY NIGHT AND EARLY THURSDAY. WITH THIS IN MIND...SURFACE WINDS...ESPECIALLY WEST OF INTERSTATE 57 IN ILLINOIS...INTERSTATE 55 IN SOUTHEAST MISSOURI AND ALONG INTERSTATE 64 IN SOUTHERN ILLINOIS AND SOUTHWEST INDIANA WILL INCREASE TO NEAR 15 KNOTS AFTER 9 AM CDT TODAY...PERSISTING THROUGH THE EARLY TUESDAY EVENING. GIVEN THE LOWERED THRESHOLD FOR WINDS ON AREA LAKES AND THE SOUTHERLY ORIENTATION OF THE WINDS ALONG THE LONG AXIS OF MOST OF THE WATERWAYS IN THE AREA...DECIDED TO POST A LAKE WIND ADVISORY FOR TODAY AND THIS EVENING. RETURNING TO RAIN CHANCES...A SERIES OF SHORTWAVES WILL ROTATE AROUND THE BASE OF THE APPROACHING LOW OVER THE DAKOTAS STARTING WEDNESDAY NIGHT AND INTO THURSDAY. GIVEN THIS FOCUSED LIFT AND NARROW ZONE OF INSTABILITY...INTRODUCED OR KEPT POPS IN PLACE FOR THE WESTERN TWO THIRDS OF THE WFO PAH FORECAST AREA /MAINLY SOUTHEAST MO...SOUTHERN IL...PURCHASE AREA OF WEST KENTUCKY/ FOR WEDNESDAY NIGHT AND THURSDAY. THE POPS ARE INTRODUCED IN A STAIR STEP FASHION...STARTING OUT ACROSS SOUTHERN RIPLEY/BUTLER COUNTIES IN SOUTHEAST MO...GRADUALLY WORKING NORTH AND EAST INTO SOUTHERN IL/PURCHASE AREA OF WEST KENTUCKY BY THURSDAY. THE CANADIAN /GEM/ GUIDANCE SEEMS THE MOST CONSISTENT WITH THE INTRODUCTION OF POPS/WEATHER ACROSS THE AREA. HOWEVER...GIVEN THE AREAL UNCERTAINTY OF THESE POPS WITH THE OTHER MEDIUM RANGE GUIDANCE...USED A BLENDED...BUT MORE CONSERVATIVE APPROACH IN SPREADING THE POPS/WEATHER NORTHEAST WITH TIME. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 304 AM CDT TUE MAY 28 2013 SOME POSSIBILITY OF PRECIPITATION THROUGH MOST OF THE EXTENDED PERIOD. AT THE BEGINNING OF THE PERIOD...SYNOPTICALLY SPEAKING...A BLOCKING H5 RIDGE CENTERED OVER THE MID ATLANTIC COAST WILL BEGIN TO BREAK DOWN PUTTING OUR AREA IN SOUTHWEST FLOW ALOFT AND IN THE WARM SECTOR AT THE SURFACE THROUGH FRIDAY NIGHT AS A SYSTEM DEVELOPS OVER THE CENTRAL PLAINS. MODELS DO SHOW MID LEVEL THERMAL RIDGING ACROSS THE AREA DURING THIS PERIOD BUT H7 TEMPS REMAIN AOB 10C. EVEN AT THAT THE BIG QUESTION IS WILL THERE BE ENOUGH CAPPING TO SHUT DOWN CONVECTIVE DEVELOPMENT IN THE WARM SECTOR THROUGH FRIDAY NIGHT. MODELS IN DECENT AGREEMENT THAT SMALL POPS ARE WARRANTED SO KEPT THEM IN PLACE. THE BEST CHANCES FOR PRECIPITATION CONTINUE TO BE SATURDAY AND SATURDAY NIGHT AS THE AFOREMENTIONED SYSTEM ACTUALLY CROSSES OUR CWA. AS THE PARENT UPPER LEVEL TROUGH AXIS SLOWLY MAKES ITS WAY ACROSS THE AREA...PRECIPITATION CHANCES WILL DIMINISH FROM WEST TO EAST SUNDAY INTO SUNDAY NIGHT. BY MONDAY ALL PRECIPITATION SHOULD BE CLEAR OF THE CWA AS HIGH PRESSURE OVERSPREADS THE REGION. TEMPERATURES SHOULD REMAIN AOA NORMAL THROUGH THE PERIOD. && .AVIATION... ISSUED AT 553 AM CDT TUE MAY 28 2013 WITH THE LATEST REVISION TO THE PUBLIC FORECAST...WILL LIKELY NEED TO ADD SOME RAIN TO AT LEAST THE KCGI TAF THIS MORNING. ANTICIPATE VFR CEILINGS AND VISIBILITIES WILL REMAIN THE RULE FOR ALL THE WFO PAH TAF SITES AT THIS TIME. ANY RAIN ACTIVITY IN OR NEAR THE TAF SITES SHOULD NOT BE A FACTOR AFTER 20Z-21Z TODAY. SUSTAINED SURFACE WINDS WILL PICK UP IN THE 10-15 KNOT RANGE WITH HIGHER GUSTS FROM THE 180-220 DEGREE DIRECTIONAL RANGE THIS MORNING AND INTO THIS AFTERNOON. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR ILZ075>078-080>094. MO...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR MOZ076-086-087-100-107>112-114. IN...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR INZ081-082-085>088. KY...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR KYZ001>022. && $$ UPDATE...SMITH SHORT TERM...SMITH LONG TERM...JP AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS PADUCAH KY
305 AM CDT TUE MAY 28 2013 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 304 AM CDT TUE MAY 28 2013 THE MESOSCALE CONVECTIVE SYSTEM OVER NORTHWEST/NORTH CENTRAL MO OVERNIGHT SHOULD EVENTUALLY DIMINISH BEFORE IT REACHES THE SOUTHERN IL/SOUTHEAST MISSOURI BORDER COUNTIES LATER THIS MORNING. THIS IS CONSISTENT WITH EARLIER RUNS OF THE HIGH RESOLUTION MODELS SUCH AS THE 3KM HRRR AND THE 13KM RAP GUIDANCE. PREVIOUSLY INTRODUCED /WITH THE MONDAY MORNING FORECAST PACKAGE/ SOME CHANCE POPS/WEATHER IN THE EXTREME SOUTHEAST PENNYRILE THIS AFTERNOON...BUT THE SIGNAL HAS NOT BEEN CONSISTENT ENOUGH TO WARRANT A MENTION WITH THIS PACKAGE. DAYSHIFT WILL STILL NEED TO WATCH FOR THIS CONVECTIVE POTENTIAL. FOR THE MOST PART DRY CONDITIONS SHOULD PREVAIL WITH CAPPING ALOFT THROUGH MOST OF THE DAYTIME HOURS ON WEDNESDAY. THE MID-ATLANTIC/SOUTHEAST U.S. RIDGE BRIEFLY HOLDS IN PLACE WHILE THE SURFACE AND UPPER LEVEL FLOW BECOME MORE SOUTH/SOUTHWEST IN ORIENTATION STARTING LATE TONIGHT INTO WEDNESDAY WITH AN APPROACHING LOW. THE PRESSURE/HEIGHT GRADIENT TIGHTENS UP FROM THE WEST AS AN NORTHWESTWARD TILTED SURFACE-UPPER LEVEL LOW MOVES OUT OF THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS /MAINLY IN THE THE DAKOTAS/ BY WEDNESDAY NIGHT AND EARLY THURSDAY. WITH THIS IN MIND...SURFACE WINDS...ESPECIALLY WEST OF INTERSTATE 57 IN ILLINOIS...INTERSTATE 55 IN SOUTHEAST MISSOURI AND ALONG INTERSTATE 64 IN SOUTHERN ILLINOIS AND SOUTHWEST INDIANA WILL INCREASE TO NEAR 15 KNOTS AFTER 9 AM CDT TODAY...PERSISTING THROUGH THE EARLY TUESDAY EVENING. GIVEN THE LOWERED THRESHOLD FOR WINDS ON AREA LAKES AND THE SOUTHERLY ORIENTATION OF THE WINDS ALONG THE LONG AXIS OF MOST OF THE WATERWAYS IN THE AREA...DECIDED TO POST A LAKE WIND ADVISORY FOR TODAY AND THIS EVENING. RETURNING TO RAIN CHANCES...A SERIES OF SHORTWAVES WILL ROTATE AROUND THE BASE OF THE APPROACHING LOW OVER THE DAKOTAS STARTING WEDNESDAY NIGHT AND INTO THURSDAY. GIVEN THIS FOCUSED LIFT AND NARROW ZONE OF INSTABILITY...INTRODUCED OR KEPT POPS IN PLACE FOR THE WESTERN TWO THIRDS OF THE WFO PAH FORECAST AREA /MAINLY SOUTHEAST MO...SOUTHERN IL...PURCHASE AREA OF WEST KENTUCKY/ FOR WEDNESDAY NIGHT AND THURSDAY. THE POPS ARE INTRODUCED IN A STAIR STEP FASHION...STARTING OUT ACROSS SOUTHERN RIPLEY/BUTLER COUNTIES IN SOUTHEAST MO...GRADUALLY WORKING NORTH AND EAST INTO SOUTHERN IL/PURCHASE AREA OF WEST KENTUCKY BY THURSDAY. THE CANADIAN /GEM/ GUIDANCE SEEMS THE MOST CONSISTENT WITH THE INTRODUCTION OF POPS/WEATHER ACROSS THE AREA. HOWEVER...GIVEN THE AREAL UNCERTAINTY OF THESE POPS WITH THE OTHER MEDIUM RANGE GUIDANCE...USED A BLENDED...BUT MORE CONSERVATIVE APPROACH IN SPREADING THE POPS/WEATHER NORTHEAST WITH TIME. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 304 AM CDT TUE MAY 28 2013 SOME POSSIBILITY OF PRECIPITATION THROUGH MOST OF THE EXTENDED PERIOD. AT THE BEGINNING OF THE PERIOD...SYNOPTICALLY SPEAKING...A BLOCKING H5 RIDGE CENTERED OVER THE MID ATLANTIC COAST WILL BEGIN TO BREAK DOWN PUTTING OUR AREA IN SOUTHWEST FLOW ALOFT AND IN THE WARM SECTOR AT THE SURFACE THROUGH FRIDAY NIGHT AS A SYSTEM DEVELOPS OVER THE CENTRAL PLAINS. MODELS DO SHOW MID LEVEL THERMAL RIDGING ACROSS THE AREA DURING THIS PERIOD BUT H7 TEMPS REMAIN AOB 10C. EVEN AT THAT THE BIG QUESTION IS WILL THERE BE ENOUGH CAPPING TO SHUT DOWN CONVECTIVE DEVELOPMENT IN THE WARM SECTOR THROUGH FRIDAY NIGHT. MODELS IN DECENT AGREEMENT THAT SMALL POPS ARE WARRANTED SO KEPT THEM IN PLACE. THE BEST CHANCES FOR PRECIPITATION CONTINUE TO BE SATURDAY AND SATURDAY NIGHT AS THE AFOREMENTIONED SYSTEM ACTUALLY CROSSES OUR CWA. AS THE PARENT UPPER LEVEL TROUGH AXIS SLOWLY MAKES ITS WAY ACROSS THE AREA...PRECIPITATION CHANCES WILL DIMINISH FROM WEST TO EAST SUNDAY INTO SUNDAY NIGHT. BY MONDAY ALL PRECIPITATION SHOULD BE CLEAR OF THE CWA AS HIGH PRESSURE OVERSPREADS THE REGION. TEMPERATURES SHOULD REMAIN AOA NORMAL THROUGH THE PERIOD. && .AVIATION... ISSUED AT 1130 PM CDT MON MAY 27 2013 SHOULD BE A QUIET 24 HOURS AS THE MAIN AXIS OF ACTIVITY STAYS TO OUR NORTH AND WEST...WHERE THE BEST UPPER FLOW AND SFC WARM FRONT WILL BE SITUATED. MEANWHILE...IN OUR AREA...BEING SOUTH OF THE FRONT...WE SHOULD CONTINUE TO SEE SOME CLOUDINESS (ALL VFR) FROM TIME TO TIME...WITH GUSTY SOUTH WINDS AT TIMES...MAINLY IN THE AFTERNOON. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR ILZ075>078-080>094. MO...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR MOZ076-086-087-100-107>112-114. IN...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR INZ081-082-085>088. KY...LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR KYZ001>022. && $$ SHORT TERM...SMITH LONG TERM...JP AVIATION...CW
AREA FORECAST DISCUSSION
NWS JACKSON KY
135 AM EDT TUE MAY 28 2013 .UPDATE... ISSUED AT 134 AM EDT TUE MAY 28 2013 NO UPDATE TO THE FORECAST WAS REQUIRED. UPDATE ISSUED AT 1050 PM EDT MON MAY 27 2013 FORECAST ON TRACK. UPDATED GRIDS TO REFLECT CURRENT CONDITIONS. HRRR MODEL INDICATING AN AREA OF LIGHT SHOWERS ENTERING THE BLUEGRASS COUNTIES WHICH IS CURRENTLY IN THE FORECAST. THE SHOWERS THEN DISSIPATE BUT RE-EMERGE NEAR THE CENTER OF OUR CWFA WITH THE BETTER TERRAIN AROUND 08Z BEFORE ONCE AGAIN DISSIPATING AN HOUR OR SO LATER. DID NOT INCLUDE THIS FEATURE IN THE FORECAST AS THE PCPN LOOKS VERY LIGHT...IF AT ALL...AND THE HRRR IS THE ONLY MODEL INDICATING THIS PCPN. UPDATE ISSUED AT 845 PM EDT MON MAY 27 2013 MESOSCALE COMPLEX BEGINNING TO SWEEP INTO WRN KY. TOPS HAVE WARMED SIGNIFICANTLY OVER THE PAST COUPLE HOURS EVEN AS THE LEADING EDGE OF THE PCPN HAS FORMED ON THE OUTFLOW FROM PREVIOUS STORMS IN CNTRL ILL. WINDS HAVE DIMINISHED TO LIGHT...SO WILL BE ABLE TO REMOVE EVENING WORDING AND FCST ONLY LIGHT WINDS TONIGHT. MOST MODELS AND TIME HEIGHT SECTIONS INDICATE THAT THERE MAY BE ENUF OF THE PCPN HOLD TOGETHER TO GIVE OUR BLUEGRASS COUNTIES A BRIEF LIGHT RAIN SHOWER. EVEN WITH NO PCPN FOR THE REST OF ERN KY...THE COMPLEX WILL PUSH ADDITIONAL CLOUD COVER AND WILL GO WITH MOSTLY CLOUDY OVERNIGHT. UPDATE ISSUED AT 625 PM EDT MON MAY 27 2013 NO PCPN WITHIN THE STATE AND THE STORMS IN ILL ARE EITHER MOVING NORTH OR THE SOUTH END IS DISSIPATING. NEW MODELS INDICATE THE PCPN WILL MOVE ACROSS IND/OH TO OUR NORTH BUT NOT INTO ERN KY DUE TO A SIGNIFICANT LOW LEVEL RIDGE EXTENDING INTO THE COMMONWEALTH FROM THE SOUTHERN ATLANTIC COAST. SWRN WINDS ARE STILL BREEZY BUT SHOULD DIMINISH WITH THE SETTING SUN. WILL FURTHER UPDATE WHEN WINDS DECREASE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 310 PM EDT MON MAY 27 2013 A WARM FRONT CONTINUES TO LIFT TO THE NORTH AND EAST OUT OF THE CWA AND AS OF 3 PM WAS LOCATED FROM SOUTHEASTERN INDIANA EAST INTO SOUTHERN OH AND THEN SOUTHEAST INTO THE WV COALFIELDS. AS OF MID AFTERNOON...A RATHER ZONAL PATTERN WAS IN PLACE ACROSS MUCH OF THE CONUS WITH A TROUGH WORKING INTO THE WEST COAST OF THE CONUS...AND A SHORTWAVE TROUGH MOVING ACROSS THE UPPER MS VALLEY WHILE A DEEP TROUGH CONTINUES TO WORK THROUGH THE CANADIAN MARITIMES. THE SHORTWAVE TROUGH OVER THE UPPER MS VALLEY WILL MOVE INTO THE NORTHERN GREAT LAKES TONIGHT AND INTO THE DAY ON TUE WITH RIDING GRADUALLY BUILDING ACROSS THE SOUTHEASTERN STATES AND SOUTHERN APPALACHIANS THROUGH THE END OF THE PERIOD. GENERALLY FLAT CU HAS DEVELOPED SO FAR OVER THE JKL CWA BUT WITH DEWPOINTS IN THE UPPER 50S NEAR THE VICINITY AND JUST BEHIND THE WARM FRONT SOME ISOLATED SHRA AND OR TSRA CANNOT BE RULED OUT THROUGH THIS EVENING. CU SHOULD DISSIPATE AS WE MOVE TOWARD SUNSET...BUT AT LEAST SOME DEBRIS CLOUDS FROM CONVECTION NOW OVER THE MS VALLEY SHOULD EVENTUALLY WORK ACROSS THE REGION TONIGHT. IT WOULD SEEM THAT DRIER AIR OVER MUCH OF KY DOWN IN THE TN VALLEY SHOULD LEAD TO THE SOUTHERN END OF THIS COMPLEX WEAKENING AS IT WORKS EAST THIS EVENING AND INTO THE OVERNIGHT. THE LATEST HRRR HANDLING OF IT SEEMS MOST REASONABLE AND THE 12Z NAM SEEMS TO BE OVERDOING CONVECTION ATTM IN THE LOWER OH VALLEY EAST OF THE COMPLEX OVER MO AND IL. THE GFS ALSO HAS SOME LATE NIGHT CONVECTION OVER THE CWA AS WELL. THE 12Z ECMWF KEEPS ALL THE ACTION CLOSER TO THE WARM FRONT. OPTED TO GO WITH SOME SLIGHT CHANCES MAINLY THIS EVENING ACROSS THE NORTH...NORTH OF THE MTN PARKWAY..BUT CONFIDENCE IN THIS IS NOT HIGH. MOISTURE SHOULD REMAIN LIMITED AND AT THIS POINT ANY TRIGGERS HARD TO DISCERN FOR CONVECTION ON TUE. THERE MAY BE A WEAK SHORTWAVE OR TO WORKING AROUND THE RIDGE...BUT WITH HEIGHTS PROGGED TO RISE ON TUE INTO TUE NIGHT...WE HAVE OPTED TO GO WITH A DRY FORECAST FOR TUE. TEMPERATURES SHOULD MODERATE FURTHER ON TUE...INTO THE MID TO UPPER 80S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 300 PM EDT MON MAY 27 2013 RIDGING WILL HOLD OVER THE EASTERN US THROUGH THE END OF THE WEEK. THIS WILL KEEP OUR AREA WEST OF THE HIGH PRESSURE AREA IN AN AREA OF RETURN FLOW. THIS WILL LEAD TO AN EXTENDED PERIOD OF MILD NIGHTS AND WARM DAYS. INSTABILITY WILL GREATLY INCREASE FROM WEDNESDAY ONWARD DURING THE DAYLIGHT HOURS...BUT WE WILL BE LACKING ANY TRIGGERS. MODELS ARE STILL LIKELY OVER AGGRESSIVE WITH THE AMOUNT OF SURFACE MOISTURE EACH DAY...SO LIKELY OVERDOING THE CAPE. HOWEVER...SOME GOOD CU FIELDS SHOULD DEVELOP EACH AFTERNOON...AND IT MAY BE POSSIBLE TO POP A VERY ISOLATED SHOWER OR STORM ALONG THE HIGHER RIDES IN THE SOUTHEAST EACH AFTERNOON FROM WEDNESDAY THROUGH FRIDAY. EACH DAY SHOULD FEATURE A SLIGHT BETTER CHANCE OF THIS HAPPENING AS DEWPOINTS SHOULD CONTINUE TO INCH UP THROUGH THE REMAINDER OF THE WEEK. BY THIS WEEKEND...HIGH PRESSURE WILL RELINQUISH ITS HOLD ON THE AREA AS A MID LEVEL SHORTWAVE APPROACHES FROM THE WEST. INCREASING FLOW AHEAD OF THIS FEATURE ON SATURDAY...COULD YIELD A BETTER SHOT OF AN ISOLATED SHOWER OR STORM BY SATURDAY AFTERNOON. THE CHANCES FOR SHOWERS AND STORMS WILL INCREASE HEADING INTO SUNDAY AS THIS TROUGH PUSHES EAST ACROSS THE AREA. PRESENTLY...MODELS IN FAIRLY GOOD AGREEMENT ON TIMING...SO CONFIDENCE REMAINS HIGHER THAN NORMAL FOR DAY 7. WITH THE FRONTAL PASSAGE...SLIGHTLY COOLER WEATHER SHOULD RETURN TO THE AREA BY EARLY NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 133 AM EDT TUE MAY 28 2013 VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE END OF THE PERIOD AT ALL THREE AIRPORTS. WINDS WILL REMAIN LIGHT OVERNIGHT UNDER PARTLY CLOUDY SKIES. CIGS WILL AVERAGE BETWEEN 11 AND 12 OVERNIGHT. SCATTERED CU ARE EXPECTED TO FORM OFF AND ON DURING THE DAYLIGHT HOURS TODAY...WITH SCATTERED CLOUDS ALSO PRESENT AROUND 11K. WINDS AT LOZ AND SME COULD GUST TO AROUND 15KTS DURING THE PEAK HEATING OF THE DAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...JP LONG TERM...KAS AVIATION...AR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
401 PM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL CONTINUE PUSH NORTH OF THE REGION THIS EVENING...BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS TO PORTIONS OF THE AREA. HIGH PRESSURE BECOMES ANCHORED OFF THE MID ATLANTIC COAST LATER TONIGHT THROUGH THE NEXT SEVERAL DAYS. SUMMERLIKE CONDITIONS AND GENERALLY DRY CONDITIONS WILL PREVAIL FROM WEDNESDAY INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LATEST RADAR AND SATELLITE DEPICT A FEW SHOWERS AND TSTMS TO THE WEST OF THE CWA ALONG THE EAST SLOPE OF THE APPALACHIANS AND THE PIEDMONT. IN GENERAL...THE HIGH RES MODELS HAVE BEEN OVERDONE THUS FAR WITH RESPECT TO COVERAGE OF THIS PRECIP...AND WILL HAVE A POP FORECAST THAT IS A LITTLE LOWER THAN WHAT THESE MODELS WOULD SUGGEST. HOWEVER...CERTAINLY CAN`T RULE OUT AT LEAST ISOLATED COVERAGE OVER SOUTHERN VA/NE NC AND SCATTERED COVERAGE FARTHER NORTH THROUGH THE EVENING HRS GIVEN SOME WEAK SHORTWAVE ENERGY PUSHING ACRS THE AREA. SHEAR IS FAIRLY WEAK/0-6KM BULK SHEAR LESS THAN 25 KT THROUGHOUT AND MID LEVEL LAPSE RATES ARE GENLY <6 C/KM SO ONLY AN ISOLATED STRONGER STORM IS EXPECTED...PRIMARILY ACRS THE FAR NORTH. SKIES CLEAR OUT FROM SW TO NE AFTER MIDNIGHT. MILD WITH LOWS MAINLY FROM THE LWR TO MID 60S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... SUMMERLIKE PATTERN LOOKS TO DEVELOP. MODELS IN GOOD AGREEMENT THAT THE 500 MB RIDGE ALOFT WILL SLOWLY BUILD ON WED AND BECOME CENTERED ACRS SE VA AND EASTERN NC THU/FRI WITH HEIGHTS AVERAGING 588-590 DM. SFC HIGH PRESSURE WILL BE NEARLY STATIONARY WELL OFF THE MID ATLC/SE COAST. SUMMER- LIKE CONDITIONS WILL DOMINATE WITH HIGHS GENLY RANGING FROM THE MID 80S NEAR THE COAST TO THE UPPER 80S TO LOWER 90S INLAND (LOCALLY IN THE UPPER 70S AT THE BEACHES OF THE EASTERN SHORE WHERE FLOW BACKS TO SSE DURING THE AFTN). LACK OF ANY REAL TRIGGER WITH THE WARM POOL ALOFT WILL LEAD TO WEAK LAPSE RATES ALOFT AND LITTLE CHC FOR ANY PCPN. A VERY ISOLATED LATE AFTN/EVENING TSTM CAN`T BE RULED OUT WITH THE STRONG SFC HEATING ...BUT COVERAGE IS EXPECTED TO BE 14% OR LESS. THE SKY WILL AVERAGE OUT PARTLY/MOSTLY SUNNY. AIRMASS WILL NOT BE THAT HUMID...AS OCEAN TEMPS ARE STILL QUITE COOL AND WITH AFTN MIXING...EXPECT DEW PTS TO DROP TO THE LWR 60S DURING THE HEAT OF THE AFTN (MID-UPR 60S IN THE MORNING HRS). SO WHILE IT WILL BE A MARGINALLY HOT PERIOD...PEAK HEAT INDICES WILL GENLY BE ABOUT THE SAME AS THE ACTUAL AIR TEMPERATURES. LOWS TEMPERATURES WILL AVERAGE IN THE MID 60S...WITH UPPER 60S MORE COMMON IN THE URBAN CENTERS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... ABOVE NORMAL TEMPS TO CONTINUE THROUGH THE WEEKEND BEFORE A COLD FRONT CROSSES THE REGION MONDAY INTO TUESDAY. MUCH BETTER AGREEMENT AMONG OPERATIONAL GUIDANCE IN THE EXTENDED WRT CNTRL CONUS TROUGH OPENING UP AND PROGRESSING EWD. MODELS CONTINUE TO STRUGGLE WITH SEVERAL PIECES OF ENERGY DIVING DOWN THE BACKSIDE OF THE UPPER TROUGH OVER THE PLAINS. MEAN FRONTAL POSITION SAT MORNING EXPECTED TO BE IN THE VICINITY OF THE GREAT LAKES...STRETCHING SWWD INTO SRN NM. WAVY UPPER LEVEL PATTERN EXPECTED TO PRODUCE SEVERAL WAVES ALONG THE SFC FRONT AS IT SLOWLY PROGRESSES EWD. WHILE LATEST GFS AND EURE DERIVE UPPER LEVEL ENERGY FROM DIFFERENT SOURCES...MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH EJECTING A SHORTWAVE EWD FROM THE LOWER MO RIVER VALLEY SUN AFTERNOON. SHORTWAVE THEN FORECAST TO PHASE WITH UPPER TROUGH AS IT TRAVERSES THE ERN STATES...REACHING THE LOCAL AREA MONDAY AFTERNOON. MEANWHILE...UPPER/SFC HIGH PRESSURE WILL BE PUSHED FARTHER OFFSHORE AS THE TROUGH APPROACHES. THE RESULT WILL BE DEEP SWLY FLOW AND MOISTURE ADVECTION OVER THE MID ATLANTIC. DEEP MOISTURE EXPECTED AS PRECIP WATER VALUES APPROACH 2 INCHES (+2 STD DEV) MON AFTERNOON. PREVIOUSLY MENTIONED WEAKNESS UNDERCUTTING THE RIDGE EXPECTED TO REMAIN WELL OFFSHORE. MODELS IN FAIR AGREEMENT (GFS ~ 6 HOURS SLOWER) WITH TIMING OF THE FRONT MON AFTERNOON THROUGH MON NIGHT. WHILE ITS STILL DAY 7...POTENTIAL FOR ONE OR MORE FRONTAL WAVES AND DEEP MOISTURE COULD PRODUCE LOCALLY HEAVY RAINFALL ACROSS THE REGION (WHICH IS NOT UNCHARACTERISTIC FOR THIS TIME OF YEAR). THETA-E ADVECTION AND TEMPS IN THE LOW/MID 80S WILL MAINTAIN A MARGINALLY UNSTABLE AIRMASS FOR THUNDERSTORM ACTIVITY. EXTENDED RANGE MODELS SUGGEST BLOCKING OVER THE NRN ATLANTIC MAY CAUSE THE TROUGH TO HANG UP ALONG THE COAST WITH SHOWERS POSSIBLY CONTINUING INTO TUES. WARM/UNSTABLE AIRMASS WITH STEEP LOW LEVEL LAPSE RATES WILL PROVIDE FOR AFTERNOON CU SAT-SUN. HOWEVER...NEAR SEASONABLE PRECIP WATERS...COOL OCEAN TEMPS (DEWPOINTS IN THE LOW/MID 60S) AND A LACK OF UPPER LEVEL SUPPORT (WEAK FLOW) WILL LIMIT AFTERNOON CONVECTION...EVEN WITH THE PRESENCE OF A WEAK LEE SIDE TROUGH. THUS HAVE CAPPED AFTERNOON POPS AT 10-14 PCT AND OVERNIGHT POPS AT 10 PCT. DAYTIME TEMPS +1 STD DEV FORECAST THROUGH SUNDAY. SLIGHTLY COOLER MONDAY (LOW/MID 80S) AND TUESDAY (UPPER 70S/LOW 80S). && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... CHALLENGING FCST NEXT 2-6 HRS AS TO WHERE AND WHEN ANY CONVECTION DVLPS. RUC SUGGESTS SOME ACTIVITY DVLPNG NEXT 2 HRS ALONG LINE OF AC CLOUD DECK CRNTLY LCTD FROM OXB-RIC WHILE NAM/SREF WAIT UNTIL AFTR 22Z FOR ACTIVITY TO DVLP ACROSS MTS THEN MOVE EAST. GIVEN THE CRNT CNDTNS LEANED TOWARD THE LATE AFTRN/ERLY EVE FOR CONVECTION TO DVLP THEN MOVE EAST. THIS TO BE MAINLY ACROSS NRN HALF OF FA (RIC/SBY) BTWN 22-02Z WHILE SRN TAF SITES (ORF/PHF/ECG) STAY DRY. THUS...WENT AHEAD AND ADDED CB TO THE RIC AND SBY TAFS TOWARD 00Z. APPEARS THAT SBY HAS THE GREATEST CHC FOR PCPN. SW WNDS AVG 10-20 KTS THRU 22Z. OTW...XPCT VFR CNDTNS WITH ONLY HIGH LVL CLDNS (AOA 12K FT) TONITE. SOME LGT BR PSBL LATE TONITE...BUT THAT WUD BE WHERE ANY RAIN OCCURS SO HELD OFF WITH ANY BR ATTM. OUTLOOK...BERMUDA HIGH PRESSURE ESTABLISHES ITSELF OFF THE COAST FOR THE REMAINDER OF THE WEEK. DRY WITH VFR CNDTNS XPCTD. && .MARINE... WARM FRONT HAS LIFTED OVER THE WATER THIS AFTERNOON WITH S/SW WINDS AOB 15 KT IN THE BAY AND AOB 20 KT COASTAL WATERS POST FRONTAL. GRADIENT BETWEEN STRONG LOW PRESSURE OVER THE MIDWEST AND HIGH PRESSURE OVER THE WRN ATLANTIC WILL RESULT IN INCREASING WINDS ALOFT OVER THE WATERS. WAA AND A STRONG LOW LEVEL INVERSION WILL INHIBIT THESE HIGHER VELOCITY WINDS FROM REACHING THE WATER. HOWEVER...WINDS OVER THE BAY MAY STILL GUST OVER 15 KT AT TIMES THROUGH TONIGHT...ESPECIALLY WITH SLY CHANNELING. WAVEWATCH GUIDANCE BRINGS IN 5 FT SEAS 20 NM OUT TONIGHT...BUT LOOKS LIKE IT MAY BE OVERDONE. NO SCA HEADLINES ANTICIPATED ATTM TONIGHT. THEREAFTER...AN EXTENDED PERIOD OF HIGH PRESSURE/FAIR WEATHER (SUB SCA CONDITIONS) EXPECTED THROUGH THE UPCOMING WEEKEND. S/SW WINDS AOB 15 KT. WAVES 1 TO 2 FT AND SEAS 2 TO 4 FT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB LONG TERM...SAM AVIATION...MPR MARINE...SAM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
119 PM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL CONTINUE TO LIFT NORTH OF THE REGION TODAY INTO THIS EVENING...AS HIGH PRESSURE BECOMES ANCHORED OFF THE MID ATLANTIC COAST. SUMMERLIKE CONDITIONS WILL PREVAIL FROM WEDNESDAY INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... EARLIER SHRA ACTIVITY ACRS THE ERN SHORE HAS PUSHED OFF TO THE NE AND ENTIRE CWA IS IN WARM SECTOR (ASIDE FORM LOCALLY COOLER ONSHORE COASTAL ERN SHORE AREAS). WEAK SHORTWAVE ENERGY CAN BE SEEN ACRS SE OHIO/WV...WITH MORE POTENT SHORTWAVE PUSHING INTO THE WRN GREAT LAKES. AS SOME OF THIS ENERGY CROSSES THE MTNS LATER THIS AFTN/EVENING ALONG WITH SEVERAL MORE HRS OF PARTLY/MOSTLY SUNNY SKIES/SFC HEATING...EXPECT SCTD SHRA/TSRA TO DEVELOP...MAINLY OVER NORTHERN AREAS WHERE INSTABILITY AND FORCING IS A LITTLE BETTER CLOSER TO THE SFC BOUNDARY. SOME OF THE OUTFLOW ENERGY MAY THEN HELP DRIVE SOME OF THE CONVECTION TO THE SOUTH SO WILL CARRY AT LEAST 20% POPS ALL ZONES AFTER ABOUT 20Z...BUT HIGHEST POPS (40-50%) STILL LOOK TO BE OVER THE FAR NORTH...PUSHING INTO THE ERN SHORE BY 00Z. SHEAR IS FAIRLY WEAK/0-6KM BULK SHEAR LESS THAN 25 KT THROUGHOUT AND MID LEVEL LAPSE RATES ARE GENLY <6 C/KM SO ONLY AN ISOLATED STRONGER STORM IS EXPECTED...PRIMARILY ACRS THE FAR NORTH. MADE ONLY MINOR CHANGES TO LATEST GRIDDED FORECAST/DATABASE. MAX TEMPS TODAY WILL BE MAINLY LWR-MID 80S WELL INLAND...75-80 ALONG THE IMMEDIATE COAST (AND LOCALLY COOLER ERN SHORE BEACHES). && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... WED-THU...BLDG RDG ALOFT/H5 HEIGHTS INCREASING TO 588-590 DM COMBINED WITH NEAR STATIONARY SFC HI PRES IN THE WRN ATLC...WILL RESULT IN SUMMER-LIKE CONDS WED-THU. LACK OF ANY REAL TRIGGER WITH THE WARM POOL ALOFT WILL LEAD TO WEAK LAPSE RATES ALOFT AND LITTLE CHC FOR ANY PCPN. A VERY ISOLATED LATE AFTN/EVENING TSTM CAN`T BE RULED OUT WITH TEMPS RISING INTO THE UPR 80S/LWR 90S OVER MOST OF THE REGION...BUT COVERAGE EXPECTED TO BE 14% OR LESS. THE SKY WILL AVERAGE OUT PRTLY/MSTLY SNY. AIRMASS WILL NOT BE THAT HUMID...AS OCEAN TEMPS ARE STILL QUITE COOL AND WITH AFTN MIXING...EXPECT DEW PTS TO DROP TO THE LWR 60S DURING THE HEAT OF THE AFTN (MID- UPR 60S IN THE MORNG HRS). && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LITTLE CHANGE IN THE EXTENDED AS STRONG HIGH PRESSURE AND FAIR WEATHER PREVAIL. A COLD FRONT IS FORECAST TO APPROACH THE REGION DURING THE UPCOMING WEEKEND. MEDIUM RANGE MODELS CONTINUE TO DEPICT MEAN RIDGE OVER THE EAST AND TROUGH OVER THE CNTRL CONUS DURING THE BEGINNING OF THE EXTENDED PERIOD. HOWEVER...MODELS CONTINUE TO STRUGGLE WITH THE EVOLUTION AND PROGRESSION OF THE CNTRL CONUS TROUGH EWD THROUGH THE END OF THE PERIOD. STRONG SPEED MAX EXPECTED TO ROUGH THE BASE OF THE UPPER TROUGH FRI INTO SAT OVER THE UPPER MIDWEST...EJECTING THE LEADING SHORTWAVE OVER THE GREAT LAKES AND INTO SE CANADA. MODELS THEN STRUGGLE WITH ADDITIONAL ENERGY DIVING DOWN THE BACKSIDE OF THE TROUGH. THIS SHORTWAVE ENERGY IS EXPECTED TO ROUND THE BASE OF THE UPPER TROUGH IN THE VICINITY OF THE LOWER MO RIVER VALLEY SUNDAY MORNING. ACCORDING TO THE 27/12Z GFS...SHORTWAVE THEN TRAVERSES THE TN VALLEY MONDAY...PUSHING A COLD FRONT THROUGH THE MID ATLANTIC MONDAY AFTERNOON. 27/00Z ECMWF DEPICTS MUCH WEAKER SHORTWAVE ENERGY OVER THE MID ATLANTIC...BUT THE TIMING OF THE FRONT MONDAY AFTERNOON IS SIMILAR TO THE GFS. ECMWF SUGGESTS A MUCH WEAKER FRONT WITH LESS PRECIP. WILL CONTINUE TO MONITOR FUTURE MODEL RUNS AS DETAILS ARE WORKED OUT AND THIS IS STILL SEVERAL DAYS OUT. WILL INTRODUCE CLIMO POPS (SLIGHT CHANCE) MONDAY AFTERNOON. MEANWHILE...STRONG UPPER RIDGE WILL REMAIN ANCHORED OVER THE EAST FRIDAY. RIDGE AXIS AND UPPER HIGH WILL SLIDE OFFSHORE SAT...AS SWLY FLOW RETURNS. WEAKNESS UNDER THE RIDGE MAY LIFT TOWARD THE COAST SUN-MON...BRINGING ADDITIONAL MOISTURE/CLOUD COVER. EXPECT THIS FEATURE (IF FUTURE MODEL RUNS STILL PRODUCE THIS FEATURE) TO REMAIN OFFSHORE DUE TO THE APPROACHING COLD FRONT/UPPER TROUGH. WARM/UNSTABLE AIRMASS AND STEEP LOW LEVEL LAPSE RATES WILL PROVIDE FOR AFTERNOON CU EACH DAY. HOWEVER...NEAR SEASONABLE PRECIP WATERS AND A LACK OF UPPER LEVEL SUPPORT (WEAK FLOW) WILL LIMIT AFTERNOON CONVECTION...EVEN WITH THE PRESENCE OF A WEAK LEE SIDE TROUGH. THUS HAVE CAPPED AFTERNOON POPS AT 10-14 PCT AND OVERNIGHT POPS AT 10 PCT. DAYTIME TEMPS +1 STD DEV FORECAST THROUGH SUNDAY. SLIGHTLY COOLER MONDAY WILL FRONTAL PASSAGE. SFC WINDS WILL GENERALLY BE SW AOB 10 KT. && .AVIATION /18Z TUESDAY THROUGH SATURDAY/... CHALLENGING FCST NEXT 2-6 HRS AS TO WHERE AND WHEN ANY CONVECTION DVLPS. RUC SUGGESTS SOME ACTIVITY DVLPNG NEXT 2 HRS ALONG LINE OF AC CLOUD DECK CRNTLY LCTD FROM OXB-RIC WHILE NAM/SREF WAIT UNTIL AFTR 22Z FOR ACTIVITY TO DVLP ACROSS MTS THEN MOVE EAST. GIVEN THE CRNT CNDTNS LEANED TOWARD THE LATE AFTRN/ERLY EVE FOR CONVECTION TO DVLP THEN MOVE EAST. THIS TO BE MAINLY ACROSS NRN HALF OF FA (RIC/SBY) BTWN 22-02Z WHILE SRN TAF SITES (ORF/PHF/ECG) STAY DRY. THUS...WENT AHEAD AND ADDED CB TO THE RIC AND SBY TAFS TOWARD 00Z. APPEARS THAT SBY HAS THE GREATEST CHC FOR PCPN. SW WNDS AVG 10-20 KTS THRU 22Z. OTW...XPCT VFR CNDTNS WITH ONLY HIGH LVL CLDNS (AOA 12K FT) TONITE. SOME LGT BR PSBL LATE TONITE...BUT THAT WUD BE WHERE ANY RAIN OCCURS SO HELD OFF WITH ANY BR ATTM. OUTLOOK...BERMUDA HIGH PRESSURE ESTABLISHES ITSELF OFF THE COAST FOR THE REMAINDER OF THE WEEK. DRY WITH VFR CNDTNS XPCTD. && .MARINE... LATEST ANALYSIS SHOWS A SFC WARM FRONT ORIENTED FROM NW TO SE FROM NRN INDIANA INTO SW VA. OBS/BUOY REORTS SHOWING GENLY LIGHT S/SW FLOW ACROSS THE AREA THIS MORNING..WITH LIGHT WINDS EXPECTED TO CONTINUE THROUGH THIS MORNING. FRONT WILL PUSH NORTH ACROSS THE WATERS BY EARLY AFTN, WITH SSW WINDS INCREASING TO 10-15 KT THIS AFTN/TNGT. DESPITE TIGHTENING PRESSURE GRADIENT, WAA AND A STRONG LLVL INVERSION WILL PREVENT HIGHER VELOCITY WINDS FROM MIXING DOWN TO THE WATER SFC. THEREAFTER, AN EXTENDED PERIOD OF SUB-SCA CONDITIONS EXPECTED THROUGH THE UPCOMING WEEKEND, AS HIGH PRESSURE REMAINS ANCHORED JUST OFF THE SE COAST. S/SW WINDS AOB 15 KT. WAVES 1 TO 2 FT AND SEAS 2 TO 4 FT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...TMG NEAR TERM...LKB/TMG SHORT TERM...LKB/TMG LONG TERM...SAM AVIATION...MPR MARINE...MAM
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
1040 AM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT MOVE NORTH OF THE AREA TODAY...WITH A SHORTWAVE PASSING BY JUST NORTH OF THE AREA. MUCH WARMER AIR IS EXPECTED BEHIND THE WARM FRONT FOR THE SECOND HALF OF THE WEEK AS A BERMUDA HIGH SETS UP OFFSHORE. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THOUGH A BULK OF THE PRECIP THIS MRNG AND THROUGHOUT THE DAY WILL STAY NORTH OF THE MASON-DIXON LINE. THE COMBINATION OF ANY GOOD AMNT OF CLEARING...SLY WINDS INCREASING DEWPOINTS...TEMPS GRADUALLY CLIMBING AND WEAK LOW LEVEL BOUNDARIES COULD KICK OFF SOME ISOLATED SHOWERS AND TSTMS AS THE DAY PROGRESSES. EVIDENCE OF THIS HAS BEEN OCCURRING ALONG AND E OF I-95 FROM DC TO BALT MID MRNG...W/ A BATCH OF CELLS THAT DEVELOPED ALONG A WEAK BOUNDARY AND PRODUCED LOCALLY HEAVY RAIN. AS THE DAY PROGRESSES AND CONVECTIVE PARAMETERS INCREASE...THIS WILL BECOME MORE FAVORABLE FOR STRONGER CELLS - THOUGH ONLY A HANDFUL OF STRONG/SEVERE STORMS EXPECTED AT BEST. LOCAL GUIDANCE LIKE THE HRRR AND WRF SOLUTIONS SHOW ANOTHER WAVE OR TWO OF WEAK INDIVIDUAL CELLS ALONG AND E OF I-95 THRU LATE MRNG...BUT THE REST OF THE AREA WILL LARGELY CLEAR OUT OVER THE NEXT COUPLE OF HRS. THIS WILL BE GOOD FOR THE BUILDING UP OF FAVORABLE CONVECTIVE PARAMETERS. HIGHS TODAY WILL APPROACH 80...AND ALONG W/ DEWPOINTS GRADUALLY INCREASING INTO THE L60S...THIS WILL BE ENOUGH FOR THE DEVELOPMENT OF SCATTERED SHOWERS/TSTMS DURING THE LATER PORTIONS OF THE AFTN/EVE. THE LOCALIZED UPPER SHORTWAVE THAT WILL BE SLIDING OFF THE NJ COAST LATER TODAY - AND WHAT IS ULTIMATELY RESPONSIBLE FOR THE ACTIVITY TODAY - WILL SKIRT THE NRN PORTIONS OF THE CWA THIS AFTN AND EVENTUALLY PULL ANY EARLIER CONVECTION OFF THE COAST LATER TONIGHT. && .SHORT TERM /10 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... WITH THE WARM FNT N OF THE AREA TNGT THERE COULD BE ISOLD EVE CNVCTN...THEN M CLDY SKIES. A MILD NGT W/ LOWS IN THE 60S...M50S IN THE HIGHLANDS...A70 IN THE CITIES. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... UPPER-LEVEL HIGH PRESSURE WILL BUILD OVER THE REGION WHILE BERMUDA HIGH SETS UP OVER THE ATLANTIC. SUBSIDENCE FROM THE UPPER-LEVEL HIGH ALONG WITH A SOUTHWEST FLOW AROUND THE BERMUDA HIGH WILL ALLOW FOR HOT AND HUMID CONDITIONS. MAX TEMPS WEDNESDAY WILL REACH THE UPPER 80S AND LOWER 90S ACROSS MOST LOCATIONS. WARM AND HUMID CONDITIONS WILL CONTINUE WEDNESDAY NIGHT. MIN TEMPS WILL RANGE FROM THE 60S ACROSS MOST LOCATIONS TO THE LOWER AND MIDDLE 70S IN DOWNTOWN WASHINGTON/BALTIMORE. UPPER-LEVEL HIGH PRESSURE REMAIN OVER THE REGION THURSDAY THROUGH SATURDAY WHILE BERMUDA HIGH REMAINS OVER THE ATLANTIC. HOT AND HUMID CONDITIONS ARE EXPECTED DURING THIS TIME...WHICH WILL LEAD TO THIS SEASONS FIRST HEAT WAVE. MAX TEMPS WILL REACH THE 90S ACROSS MANY LOCATIONS EACH DAY UNDER PLENTY OF SUNSHINE. TERRAIN CIRCULATION COULD LEAD TO AN ISOLATED T-STORM DURING THE AFTERNOON/EVENING HOURS...BUT THE CAPPING INVERSION SHOULD REMAIN STRONG ENOUGH TO KEEP MOST AREAS DRY. THEREFORE...T-STORMS ARE NOT IN THE FORECAST AT THIS TIME. THE RIDGE WILL WEAKEN SUNDAY AND MONDAY ALLOWING FOR A COLD FRONT TO MOVE INTO THE AREA...BRINGING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... ALTHO M CLDY VFR CONDS TDA/TNGT. ISOLD TSTMS PSBL THIS AFT/EVE. HIGH PRESSURE WILL REMAIN OVER THE TERMINALS WEDNESDAY THROUGH SATURDAY...CAUSING SOUTHWESTERLY WINDS. WIND GUSTS AROUND 15 KNOTS ARE EXPECTED DURING THE AFTERNOON AND EVENING HOURS EACH DAY. VFR CONDITIONS WILL DOMINATE...BUT BRIEF PERIODS OF SUBVFR VSBYS ARE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY. A COLD FRONT WILL APPROACH THE TERMINALS SUNDAY AND MONDAY...BRINGING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. && .MARINE... WINDS BLO SCA VALUES TDA/TNGT. ONLY THREAT WOULD BE AFTN/EVE TSTMS..W/ THE BEST CHCS IN THE NRN CHES BAY. BERMUDA HIGH WILL SET UP OVER THE ATLANTIC WEDNESDAY THROUGH SATURDAY. SOUTHERLY WINDS ARE EXPECTED. WIND GUSTS WILL COME CLOSE TO SCA CRITERIA...BUT FORECASTED GUSTS ARE CAPPED AROUND 15 KNOTS DUE TO THE RELATIVELY COOLER WATERS. A COLD FRONT WILL APPROACH THE WATERS SUNDAY AND MONDAY...BRINGING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...GMS PREV DISCUSSION...WOODY!/BJL
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1019 PM EDT WED MAY 29 2013 .SYNOPSIS... ISSUED AT 432 PM EDT WED MAY 29 2013 UNSETTLED WEATHER WILL BE THE RULE THROUGH THE NEAR FUTURE...AS A WARM FRONT GRADUALLY LIFTS NORTH INTO ONTARIO BY THURSDAY. THIS FEATURE WILL PROVIDE CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS THROUGH MID DAY ON THURSDAY. WE`LL GET A BREAK FROM THE ACTIVITY FOR THURSDAY AFTERNOON AND EVENING. BUT MORE CHANCES FOR SHOWERS AND STORMS WILL ENTER THE PICTURE FRIDAY THROUGH SUNDAY...AS A COLD FRONT SLOWLY SLIDES ACROSS THE GREAT LAKES. && .UPDATE... ISSUED AT 1019 PM EDT WED MAY 29 2013 CLEAR CONCERNS FOR THE OVERNIGHT ARE FOG AND PRECIP. AIRMASS OVER MOST OF NORTHERN MI IS PRIMED FOR FOG. MARINE LAYER HAS COME CHARGING IN FROM LAKE HURON...WITH THE OSC AWOS/SPOTTERS/ FOG IMAGERY SHOWING FOG IN THAT AREA...ALMOST UP TO APN. PLENTY OF MARINE AIR STILL IN PLACE FROM THE STRAITS NORTH AS WELL. MEANWHILE...RADIATIONAL COOLING BARELY UNDERWAY...BUT IS ALREADY REDUCING VSBYS AT PLN AND BELLAIRE. WE HAD GROUND FOG DEVELOPING IN A FIELD ADJOINING THE OFFICE RIGHT AT SUNSET. OF COURSE... FAVORABLE RADIATIONAL COOLING CONDITIONS WILL BE COMING TO AN END SOON...AS A THICK CIRRUS SHROUD IS ADVANCING ABOVE LAKE MI AND CENTRAL UPPER MI. THIS SHOULD KEEP WIDESPREAD PEA SOUP FROM FORMING...BUT HAVE STEADILY EXPANDED FOG MENTION AND SEVERITY IN THE GRIDDED FORECASTS. HAVE ALSO REJIGGERED PRECIP CHANCES. RADAR TRENDS IN WI REMAIN SOMEWHAT OMINOUS AT 1ST GLANCE. BUT THE 00Z SOUNDING FROM GRB IS RELATIVELY DRY (PWAT 0.9) AND CAPPED...AND THAT AIRMASS ISN/T GETTING MORE UNSTABLE WITH TIME. 00Z APX SOUNDING WAS LESS UNSTABLE AND MORE CAPPED. THOUGH A WARMER/MORE MOIST AIRMASS WILL TRY TO WORK NORTHWARD INTO NORTHERN MI...THE LOW LEVEL JET WILL BE MUCH STRONGER TO OUR WEST. UPSTREAM MCS APPEARS TO BE EVOLVING IN RESPONSE...WITH LIGHTNING BECOMING LESS COMMON ALONG IT/S LEADING (EASTERN) EDGE...AND MORE COMMON ALONG THE RIGHT REAR (SOUTHWEST) FLANK. THUS...THE EARLIER FORECAST THINKING STILL APPEARS SOUND....LIFTING THE MCS REMNANTS NE-WARD ACROSS WI AND UPPER MI OVERNIGHT. LATEST HRRR RUNS REMAIN SUPPORTIVE OF THIS THINKING...WITH NO PRECIP IN THIS CWA EXCEPT IN FAR WESTERN CHIP/MACK. HAVE REMOVED CHANCE POPS FROM NE LOWER...ADDED SMALL CHANCE POPS ALONG THE NW LOWER MI COAST...AND RETAINED CHANCE POPS IN EASTERN UPPER (HIGHEST IN WESTERN CHIP/MACK). MIN TEMPS WILL BE QUITE MILD OUTSIDE OF MARINE-INFLUENCED AREAS. UPDATE ISSUED AT 739 PM EDT WED MAY 29 2013 APPEARS TO BE SAFE TO PULL PRECIP FROM THE SAGINAW BAY REGION THIS EVENING. CU FIELD IS IN DECLINE...AND EARLIER ECHOES ON RADAR HAVE EXITED. HAVE REDUCED CLOUD COVER SUBSTANTIALLY THIS EVENING...PER SAT TRENDS...ESPECIALLY IN NORTHERN LOWER MI. HAVE EXPANDED FOG INTO PARTS OF NORTHERN LOWER...ESPECIALLY WHERE LOW CLOUDS AND/OR MARINE AIR LINGERED LONGEST TODAY. TEMP/DEW POINT SPREADS ARE ALREADY 10F OR LESS AT APN/PLN...AND WITH WINDS LIGHTENING AND SKIES (TEMPORARILY) CLEARING...CERTAINLY LOOKS LIKE SOME FOG COULD FORM QUITE QUICKLY...PERHAPS EVEN BY MIDNIGHT. IT WILL BE AN INTERESTING RACE...AS A CIRRUS SHROUD FROM UPSTREAM SHRA/TSRA IS STEADILY ADVANCING ACROSS WI...AND WILL BE ENCROACHING ON THE AREA LATE EVENING AND ESPECIALLY OVERNIGHT. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 432 PM EDT WED MAY 29 2013 ON THE LATEST SURFACE WEATHER MAP...1022 MB HIGH PRESSURE WAS OVER VIRGINIA WHILE 1003 MB LOW PRESSURE WAS OVER NORTHERN ONTARIO AND 992 MB LOW PRESSURE WAS OVER WESTERN KANSAS...WHILE A SURFACE WARM FRONT WAS LOCATED JUST SOUTH OF THE FORECAST AREA. SATELLITE IMAGERY SHOWED LOTS OF CLOUDS ACROSS NORTHERN MICHIGAN BUT APX RADAR WAS VOID OF RETURNS. THE MAIN SHORT TERM FORECAST CONCERNS ARE NUMEROUS AND INCLUDE THUNDERSTORM POTENTIAL ACROSS SOUTHEAST ZONES INTO THE EVENING HOURS THEN THUNDERSTORM CHANCES OVERNIGHT AND AGAIN THURSDAY ACROSS ALL OF THE COUNTY WARNING AREA. THIS EVENING...CLOUDS HAVE BEEN A REAL CHALLENGE THIS AFTERNOON AS USUAL. MARINE STRATUS CONTINUES TO PLAGUE MARINE AREAS...AS WELL AS SPILLING INTO NORTHWEST LOWER WHILE SOUTHWEST ZONES HAVE SEEN AN INCREASE IN DIURNALLY DRIVEN CU (AFTER THE LOW CLOUDS MIXED OUT EARLIER). THE TREND HAS BEEN FOR CLOUDS TO GENERALLY DISSIPATE ACROSS THE SOUTHWESTERN ZONES AND THIS SHOULD CONTINUE THROUGH THE EVENING HOURS. COULD SEE A SHOWER OR THUNDERSTORM POP UP ACROSS SOUTHEAST ZONES OVER THE NEXT FEW HOURS WHERE THERE WAS THE MOST SUN/HEATING TODAY...IN COMBINATION WITH A BIT OF CONVERGENCE FROM A LAKE BREEZE OFF OF LAKE HURON. THEREFORE...WILL CONTINUE WITH LOW CHANCE POPS DOWN THERE. SEVERE POTENTIAL LOOKS LIMITED WITH WINDS ALOFT ON THE LIGHT SIDE. OVERNIGHT...CONVECTION ACROSS EASTERN MINNESOTA AND EASTERN IOWA EXPECTED TO TRACK TOWARD THE THETA-E RIDGE MOVING INTO THE NORTHERN HALF OF THE FORECAST AREA OVERNIGHT. STILL SOME DOUBT WHETHER THESE STORMS WILL SURVIVE THIS FAR EAST...SO WILL CONTINUE TO COVER IT WITH CHANCE WORDING. SEVERE POTENTIAL REMAINS LIMITED WITH 0-6KM BULK SHEAR OF 30 KNOTS OR LESS. WARM AND MUGGY OVERNIGHT WITH LOWS RANGING FROM THE MIDDLE 50S NORTH TO THE MIDDLE 60S SOUTH. THURSDAY...WE ARE EXPECTED TO FINALLY BREAK OUT INTO THE WARM SECTOR AS THE SURFACE WARM FRONT MOVES THROUGH THE REGION LEADING TO HIGHS RANGING FROM THE UPPER 70S NORTH TO THE MIDDLE 80S SOUTHEAST. IN ADDITION...THETA-E RIDGE BUILDS IN FROM THE WEST. LOOKING AT MODEL SOUNDINGS...NOT MUCH CAPPING IN EVIDENCE SO COULD SEE A FEW INSTABILITY DRIVEN THUNDERSTORMS DEVELOPING IN THE AFTERNOON AND EARLY EVENING HOURS...SO HAVE ADDED IN LOW CHANCE POPS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 432 PM EDT WED MAY 29 2013 OVERVIEW: 4-WAVE HEMISPHERIC PATTERN IN PLACE TO START THIS FORECAST CYCLE WITH LONG WAVE TROUGHS ANCHORED OVER THE EASTERN PACIFIC (NEAR 150W) AS WELL AS FAR EASTERN CANADA (NEAR 60W)...WITH LOW AMPLITUDE RIDGING IN BETWEEN. ON THE SHORTER SCALE...FAST MID LEVEL FLOW IN PLACE ACROSS THE EASTERN PACIFIC DIGGING INTO AN INVERTED SHORT WAVE TROUGH IN THE WESTERN CONUS INTO THE PLAINS. ASSOCIATED SFC LOW CENTERED NEAR THE COLORADO/KANSAS BORDER THIS MORNING WITH A SOMEWHAT STATIONARY FRONT ARCHING UP INTO THE GREAT LAKES. SFC LOW AND STATIONARY FRONT CONTINUE TO DRIVE EPISODES OF SHOWERS AND STORMS FROM THE CENTRAL PLAINS THROUGH THE MIDWEST/LOWER GREAT LAKES. SHORT WAVE TROUGH WILL CONTINUE TO BE THE MAIN WEATHER PLAYER AS IT SLOWLY WORKS THROUGH THE PLAINS AND ULTIMATELY THE GREAT LAKES OVER THE NEXT SEVERAL DAYS. CONVECTIVE TRENDS/TIMING WILL BE THE TOUGH PART OF THE FORECAST AS THIS OCCURS. TEMPERATURES WILL INITIALLY BE ON THE WARMER SIDE OF THINGS (RAIN AND CLOUDS DEPENDENT) BUT TURN RATHER COOL AGAIN FOR THE WEEKEND AS THE TROUGH AND ASSOCIATED POCKET OF COLD AIR WORK THROUGH. SHAPING UP TO BE ANOTHER RIP-OFF SUMMER WEEKEND...SORRY. THURSDAY NIGHT AND FRIDAY...CLOSED AND NEARLY STACKED LOW PRESSURE SYSTEM EXPECTED TO BE MIGRATING SLOWLY ACROSS THE NRN PLAINS INTO THE UPPER MIDWEST THROUGH THIS TIMEFRAME WITH THE FRONT STRETCHED SOMEWHERE THROUGH THE NRN GREAT LAKES. MAIN FOCUS FOR CONVECTION THURSDAY NIGHT WILL LIKELY BE ACROSS THE MID TO UPPER MISSISSIPPI RIVER VALLEY WHERE WARM/MOIST SOUTHERLY INFLOW WILL INTERACT WITH BETTER SYNOPTIC FORCING. BUT THERE WILL BE THE CHANCE THAT SOME OF THAT ACTIVITY COULD EVENTUALLY SPREAD INTO THE GREAT LAKES THURSDAY NIGHT/FRIDAY MORNING AS MID LEVEL SHORT WAVE IMPULSE SWINGS UP INTO THE REGION. THAT SAID...TOUGH TO HAVE HIGH CONFIDENCE IN THE DETAILS AT THIS JUNCTURE GIVEN ALL THE CONVECTION THAT WILL OCCUR BETWEEN NOW AND THEN. SO FOR NOW WILL HAVE JUST CHANCY POPS OVERNIGHT THURSDAY NIGHT OVER THE WESTERN HALF OF THE CWA...AND ACROSS THE CWA ON FRIDAY. DETAILS WILL HAVE TO BE REFINED LATER. FRIDAY NIGHT THROUGH SUNDAY...PATTERN REMAINS UNSETTLED RIGHT ON THROUGH THE WEEKEND AS PESKY CLOSED LOW MAKES SLOW PROGRESS INTO THE GREAT LAKES. SHOWERS AND STORMS APPEAR MOST LIKELY ACROSS THE GREAT LAKES REGION FRIDAY NIGHT INTO SATURDAY AS THE ASSOCIATED SFC FRONT AND UPPER JET CORE PRESS INTO THE GREAT LAKES REGION...AND WILL HAVE HIGHEST POPS DURING THIS TIME. AFTER FROPA...SUNDAY SHAPING UP TO BE COOL AND DAMP ONCE AGAIN AS LIGHTER PRECIP LINGERS AND TEMPS DIP BACK BELOW NORMAL. MONDAY THROUGH WEDNESDAY...MID LEVEL TROUGH AND CORE OF COLD AIR SLOWLY RETREATS EASTWARD ON MONDAY FOLLOWED BY LOWER AMPLITUDE RIDGING FOR TUESDAY INTO WEDNESDAY. LARGE EXPANSE OF CANADIAN HIGH PRESSURE SETTLES IN FOR MONDAY AND TUESDAY WHICH WILL CLEAR THINGS OUT AND MAY LEAD MORE FROST POTENTIAL BOTH MONDAY AND TUESDAY MORNING. DAYTIME TEMPS REBOUND FOR TUESDAY AND WEDNESDAY BACK CLOSE TO NORMAL. HOWEVER...YET ANOTHER TROUGH IS SLATED TO BE DIPPING INTO THE UPPER MIDWEST/WESTERN GREAT LAKES AROUND MIDWEEK BRINGING ADDITIONAL RAIN CHANCES TO THE REGION TO ROUND OUT THE EXTENDED && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 739 PM EDT WED MAY 29 2013 SOME BR/FG TONIGHT...ESPECIALLY APN/PLN. CHANCES FOR SHRA/TSRA LATE TONIGHT PLN...THURSDAY AFTERNOON ALL SITES. WEAK RIDGE OF HIGH PRESSURE NOW OVER LAKE HURON WILL MOVE OFF TO THE EAST...ALLOWING WARM/MOIST SOUTHERLY FLOW TO RETURN TO THE REGION THURSDAY. APN/PLN SAW LIMITED HEATING/SUNSHINE TODAY...THOUGH LOWER CLOUDS ARE EXPECTED TO EXIT THE REGION THIS EVENING. THAT SHOULD ALLOW SOME FOG TO FORM...AT LEAST BEFORE A CIRRUS SHROUD FROM TSRA IN WI OVERSPREADS NORTHERN MI. THOSE TSRA WILL WEAKEN AS THEY MOVE NE...AND LARGELY MISS THE TAF SITES...THOUGH HAVE A CHANCE AT GRAZING PLN LATE TONIGHT. A CU FIELD WILL DEVELOP THURSDAY IN A WARM/MUGGY AIRMASS. SOME SHRA/TSRA WILL TRY TO GET GOING IN THE AFTERNOON...AND HAVE ADDED VCSH TO ALL TAF SITES AFTER 19Z. LIGHT WINDS TONIGHT. SOUTH WINDS THURSDAY...BREEZIEST AT MBL. && .MARINE... ISSUED AT 432 PM EDT WED MAY 29 2013 WINDS NOT EXPECTED TO BE MUCH OF AN ISSUE THROUGH TONIGHT...GENERAL SOUTHWEST GRADIENT WIND WITH SOME LAKE BREEZE INFLUENCE ON WHITEFISH BAY AND FAR NORTHERN LAKE HURON NEARSHORE ZONES. WINDS WILL BECOME MORE SOUTHERLY TONIGHT. REDUCED VISIBILITIES IN AREAS OF FOG AND HAZE WILL BE AN ISSUE THROUGH THURSDAY GIVEN RELATIVELY HUMID AIR MASS IN PLACE INTERACTING WITH COLDER LAKE WATERS. SOUTHERLY WINDS WILL INCREASE BY FRIDAY AFTERNOON...WITH SMALL CRAFT ADVISORIES LIKELY NEEDED ACROSS A MAJORITY OF THE NEARSHORE ZONES. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JZ SYNOPSIS...KB SHORT TERM...AS LONG TERM...BA AVIATION...JZ MARINE...AS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
721 PM EDT WED MAY 29 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 354 PM EDT WED MAY 29 2013 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RDG AXIS MOVING INTO THE UPR GRT LKS DOWNSTREAM OF DEEPENING UPR TROF OVER THE ROCKIES. ALTHOUGH SOME LO CLDS LINGER WITH LLVL MSTR SHOWN ON LOCAL 12Z RAOBS...COMBINATION OF SUBSIDENCE/LLVL ACYC FLOW ASSOCIATED WITH RDG AXIS AND ARRIVAL OF VERY DRY AIR ABV THE SHALLOW MSTR AS SHOWN ON THE 12Z MPX RAOB IS BRINGING DRY WX TO UPR MI. AT MID AFTN...THE LO CLDS ARE FINALLY MIXING OUT FAIRLY STEADILY. FARTHER TO THE SW...A PAIR OF SHRTWVS LIFTING NEWD OUT OF THE ROCKIES TROF ARE BRINGING SOME SHRA/TS TO COME AREAS IN THE PLAINS...ESPECIALLY OVER IOWA INTO SE MN AHEAD OF SFC-85 WARM FNT. MAIN FCST CONCERNS TNGT INTO THU WL BE SHRA/TS CHCS ASSOCIATED WITH RETURNING H85 WARM FNT AND SHRTWVS LIFTING NEWD OUT OF THE ROCKIES TROF. TNGT...MODELS ARE IN VERY GOOD AGREEMENT SHOWING CORE OF MID LVL DRY AIR OVER THE CWA EARLY THIS EVNG UNDER UPR RDG AXIS SHIFTING TO THE NE WITH APRCH OF WARM FNT TO THE SW. ALTHOUGH THE EARLY EVNG WL LIKELY BE DRY...EXPECT INCRSG SHRA/TS CHCS BY 03Z WITH APRCH OF SHRTWV NOW CAUSING SHRA/TS IN IOWA AS WELL AS AXIS OF HIER H85 DEWPTS AT NOSE OF STRENGTHENING H85 LLJ PUSHING KINX AT IWD TO 36 BY 06Z PER GFS FCST SDNGS. SINCE THE SHRTWV/MOISTENING ARE FCST TO IMPACT MAINLY THE W HALF OF THE CWA...EXPECT THE HIER POPS IN THAT AREA. IN FACT...THE ERN ZNS MAY REMAIN COMPLETELY DRY WITH KINX FCST NO HIER THAN ABOUT 25 AT ERY THRU 12Z THU. FCST SDNGS INDICATE STABILITY WL BE TOO MARGINAL FOR SVR STORMS...WITH SSI NO LOWER THAN ABOUT -1C AND MUCAPE NO HIER THAN 300-350 J/KG WITH NARROW SKINNY CAPE. EXPECT THE LOWEST MIN TEMPS OVER THE E CLOSER TO DEPARTING DRY AIRMASS. AREAS OF FOG ARE LIKELY TO FORM IN THIS AREA UNDER THE MORE PERSISTENT MID LVL DRY AIR. THU...AS WARM FNT SHIFTS TO THE N ON THU...EXPECT BULK OF LINGERING MRNG SHRA/TS OVER MAINLY THE W TO DIMINISH/END. QUESTION THEN BECOMES WHETHER ADDITIONAL CONVECTION WL FIRE IN THE WARM SECTOR AFT MRNG LO CLDS DSPT WITH DAYTIME HEATING/MIXING. THE BEST CHC FOR AFTN SHRA/TS WL BE PROBABLY BE OVER THE W...UNDER LOWER HGTS CLOSER TO CLOSED LO FCST TO DRIFT NWD THRU THE PLAINS. BUT EVEN THERE...GFS FCST SDNGS HINT AT SUBSIDENCE INVRN IN THE H75-8 LYR THAT MIGHT INHIBIT CONVECTION FOR AWHILE. IN FACT...BULK OF NUMERICAL GUIDANCE SHOWS NO SHRA/TS DVLPG UNTIL 21Z...WHEN SFC TEMPS ARE LIKELY TO RISE WELL INTO THE 80S UNDER H85 TEMPS IN THE 16-17C RANGE. MODIFIED GFS FCST SDNG AT IWD FOR T/TD 85/60 YIELDS SBCAPE NEAR 1250 J/KG. UNIDIRECTIONAL SSW FLOW AND SFC-6KM BULK SHEAR IN THE 20-30KT RANGE AS WELL AS HI FRZG LVL/WBLB ZERO OF 13.7K FT/12.6K FT WOULD INDICATE SVR THREAT IS FAIRLY SMALL. SINCE WARM FNT WL PROBABLY STALL OVER NW LK SUP...PAINTED THE HIER POPS OVER THE KEWEENAW CLOSER TO THIS BNDRY. SFC-6KM SHEAR IS FCST A BIT HIER IN THIS AREA AND UP TO 40 KTS...BUT LO CLDS SHOULD BE MORE PERSISTENT/STABILITY LOWER OVER THE KEWEENAW. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 354 PM EDT WED MAY 29 2013 WARMER THAN NORMAL TEMPERATURES AND ACTIVE WEATHER EXPECTED THROUGH THE END OF THE WORK WEEK AHEAD OF A LOW PRESSURE SYSTEM SHIFTING EASTWARD FROM THE PLAINS. A COOLING TREND IS EXPECTED OVER THE WEEKEND WITH NEAR NORMAL TEMPERATURES EXPECTED EARLY NEXT WEEK...HOWEVER OVERNIGHT LOWS ARE EXPECTED TO BE QUITE COOL EARLY NEXT WEEK WITH INLAND AREAS LIKELY REACHING THE LOW TO MID 30S. THURSDAY NIGHT THROUGH SATURDAY...UPPER LEVEL 500MB CLOSED LOW AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM CENTERED OVER THE DAKOTAS THURSDAY NIGHT WILL DRIFT SLOWLY EASTWARD INTO WESTERN MN BY THURSDAY NIGHT. THIS WILL KEEP UPPER MI IN WARM MOIST SOUTHERLY FLOW. THE BETTER MOISTURE TRANSPORT INTO THE REGION IS PROGGED TO OCCUR THURSDAY NIGHT THROUGH EARLY FRIDAY MORNING...AS PRESSURE GRADIENT IS INCREASED BETWEEN THE TROUGH TO THE WEST AND RIDGE TO THE EAST. UPPER MI IS ON THE NORTHERN FRINGES OF THIS PRESSURE GRADIENT...DIFFLUENT REGION...ALLOWING WIND SPEEDS TO DECREASE OVER UPPER MI. AS A RESULT...850MB CONVERGENCE IS ENHANCED OVER NORTHERN WI AND UPPER MI PROVIDING ENOUGH FORCING TO INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE REGION. MUCAPE VALUES ARE PROGGED TO BE AROUND 500-600 J/KG WHICH MAY BE ENHANCED A BIT AS 500MB SHORTWAVE ROTATES THROUGH THE REGION THURSDAY NIGHT. THE SURFACE LOW AND UPPER LEVEL LOW WILL THEN SHIFT FROM WESTERN MN FRIDAY MORNING INTO WI AND UPPER MI BY SATURDAY AFTERNOON. DURING THIS TIME PERIOD THE BETTER CHANCES FOR PRECIPITATION WILL SHIFT EASTWARD...REMAINING OVER MAINLY EASTERN UPPER MI AND MOST OF LOWER MI AS THE PRESSURE GRADIENT AND AFOREMENTIONED CONVERGENCE ALSO SHIFTS EASTWARD. ENOUGH MOISTURE WILL REMAIN IN PLACE OVER MUCH OF UPPER MI ALONG WITH COOLER AIR MOVING IN THROUGH THE DAY SATURDAY...TO KEEP THE CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. SATURDAY NIGHT THROUGH SUNDAY...THE LOW PRESSURE SYSTEM OVER UPPER MI SATURDAY NIGHT IS EXPECTED TO CONTINUE TO TREK EASTWARD SHIFTING TO SOUTHERN ONTARIO AND SOUTHERN QUEBEC THROUGH SUNDAY AFTERNOON. AS THIS HAPPENS...UPPER MI WILL BE PLACED ON THE BACK SIDE OF THE LOW PRESSURE SYSTEM ALLOWING COOLER AIR TO PUSH INTO THE AREA. ENOUGH WRAP AROUND MOISTURE WILL LINGER THROUGH SUNDAY AFTERNOON AND EVENING TO KEEP INCREASED CLOUD COVER OVER THE REGION ALONG WITH THE CHANCE OF SHOWERS. WHEN PLOTTING 1000-500MB OMEGA ON PLAN VIEW AND CROSS SECTIONS...INCREASED RH VALUES AND FORCING ARE COLLOCATED OVER MUCH OF THE UPPER PENINSULA THROUGH SUNDAY AFTERNOON. AS WAS THE CASE OVER THE LAST FEW SHIFTS...THE GFS TRIES TO PULL DRY AIR INTO THE REGION MUCH FASTER THAN THE EC/GEM...THEREFORE...WILL KEEP INCREASED CLOUD COVER IN THE FORECAST INTO THE LATE AFTERNOON INTO EARLY SUNDAY EVENING. THE GFS WOULD HAVE ALL CLOUD COVER OUT OF THE AREA BETWEEN 12 AND 18Z SUNDAY. SUNDAY NIGHT THROUGH WEDNESDAY...IN THE WAKE OF THE UPPER LEVEL 500MB LOW AND SURFACE LOW...EXPECT AN UPPER LEVEL 500MB RIDGE AND SURFACE HIGH TO BUILD EASTWARD FROM THE PLAINS SUNDAY NIGHT REACHING THE UPPER GREAT LAKES REGION BY LATE MONDAY MORNING. THE RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY EVENING...KEEPING CONDITIONS DRY AND SKIES MOSTLY SUNNY. SUNDAY NIGHT INTO MONDAY NIGHT...OVERNIGHT LOWS AREA EXPECTED TO BE FAIRLY COLD FOR THIS TIME OF YEAR AS 850MB TEMPS AREA EXPECTED TO DROP TO AROUND 0C TO 2C. THIS COUPLED WITH CALM WINDS...CLEAR SKIES AND DRY AIR...WILL ALLOW FOR MAXIMUM RADIATIONAL COOLING. AREAS INLAND WEST COULD FALL TO NEAR FREEZING SUNDAY NIGHT WHILE THE INLAND EAST AREAS COULD SEE NEAR FREEZING TEMPERATURES MONDAY NIGHT AS THE HIGH PRESSURE CENTER SHIFTS EASTWARD. THE NEXT AREA OF LOW PRESSURE DEVELOPING OVER SOUTHERN CANADA AND THE NORTHERN ROCKIES MONDAY AFTERNOON WILL SHIFT SLOWLY EASTWARD REACHING WESTERN UPPER MI BY LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. SIGNIFICANT TIMING AND SYSTEM INTENSITY DIFFERENCES EXIST FROM MODEL TO MODEL AND FROM MODEL RUN TO MODEL RUN CAUSING A BELOW AVERAGE CONFIDENCE LEVEL IN THE FORECAST FOR WEDNESDAY...THEREFORE HAVE DECIDED TO LEAN TOWARD A CONSENSUS OF THE MODELS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 721 PM EDT WED MAY 29 2013 VFR CONDITIONS WILL CONTINUE INTO THE EARLY EVENING AT ALL SITES WITH LARGER SCALE SUBSIDENCE/ DRYING IN THE PRESENCE OF DAYTIME HEATING/MIXING. A DISTURBANCE MOVING IN FM THE SW WL BRING THE THREAT OF SOME SHRA AND POSSIBLY A TS TO MAINLY IWD AND CMX TNGT. WITH NOCTURNAL COOLING AND RETURNING MSTR...EXPECT CONDITIONS TO DETERIORATE TO IFR/MVFR. ALTHOUGH DAYTIME HEATING/MIXING WL BRING ABOUT IMPROVEMENT ON THU. AT SAW...SIGNS ARE POINTING TO AN UPSLOPE LOW CLOUD AND FOG EVENT FROM LOW LEVEL MOISTURE COMING IN FROM LAKE MICHIGAN. ESC...MNM AND ISQ ALL HAVE LOWER VIS AND/OR LOW CIGS AND THIS WILL BE ADVECTED NORTH ON SOUTH UPSLOPE WINDS TO DETERIORATE CONDITIONS AT SAW FROM VFR TO LIFR BY LATE EVENING. MIXING AND HEATING WILL BRING BACK VFR BY MID MORNING AT SAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 354 PM EDT WED MAY 29 2013 WITH GENERALLY WEAK PRES GRADIENT AND STABLE CONDITIONS OVER LAKE SUPERIOR...EXPECT WINDS TO BE UNDER 25KT THRU THE WEEK. WIDESPREAD FOG IS LIKELY...ESPECIALLY AFTER RAINFALL OCCURS OVER THE LAKE. AT LEAST PATCHY DENSE FOG IS LIKELY INTO SAT. HIGH PRESSURE WILL MOVE INTO THE AREA SUNDAY NIGHT AND REMAIN OVERHEAD THROUGH LATE TUESDAY NIGHT...KEEPING WINDS VARIABLE AND LESS THAN 25 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KEC AVIATION...07 MARINE...KEC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
355 PM EDT TUE MAY 28 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 352 PM EDT TUE MAY 28 2013 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE GREAT LKS DOWNSTREAM OF DEEPENING TROF OVER THE WRN CONUS. THERE ARE A PAIR OF SHRTWVS IN THE NRN PLAINS/UPR MS RIVER VALLEY LIFTING NEWD IN THE SW FLOW ALF BTWN THE LARGER SCALE FEATURES. THE FIRST OF THESE IS MOVING THRU IOWA AND CAUSING A BAND OF SHRA/SOME TS N OF SFC/H85 WARM FNT IN THE LOWER GREAT LKS. THE BULK OF THESE SHRA ARE MOVING ENEWD THRU LWR MI AND ON TRACK TO MISS THE CWA...BUT SOME SCT -SHRA EXTENDING AS FAR W AS MPX ARE SHIFTING NEWD THRU WI AND CLOSING IN ON THE SCNTRL CWA. THE HEAVIER/MOST WDSPRD SHRA MISSING THE CWA TO THE SE APPEAR BEST CORRELATED WITH THE SHARPEST H85-5 QVECTOR CNVGC...WHILE THE SHRA IN WI APPEAR TIED TO ISENTROPIC ASCENT ON THE 300-305K SFCS /H85-7/. OTRW...SKIES ARE CLDY OVER THE CWA N OF THE WARM FNT WITH AMPLE MSTR IN THE SFC-H7 LYR SHOWN ON THE 12Z MPX/GRB/APX RAOBS. THESE CLDS HAVE GREATLY RESTRICTED THE DIURNAL RECOVERY OF TEMP. BEHIND THE OTHER SHRTWV OVER NDAKOTA...A MUCH DRIER AIRMASS IS NOTED SHIFTING EWD THRU THE NRN PLAINS. FCST CONCERNS IN THE SHORT TERM INVOLVE POPS ASSOCIATED WITH SHRTWV/WARM FNT TO THE S AND THEN DRYING TRENDS LATER TNGT INTO WED AS DRY AIRMASS IN THE NRN PLAINS MOVES INTO THE UPR LKS. TNGT...SINCE DEEPER H85-5 QVECTOR CNVGC IS PROGGED TO DRIFT ENEWD THRU LWR MI AND INTO SE ONTARIO...EXPECT HEAVIER SHRA TO REMAIN SE OF UPR MI. HOWEVER...WITH SHRTWV IN IOWA APRCHG THE CWA THRU WI AND BAND OF ISENTROPIC ASCENT ON THE 300-305K SFCS IMPACTING MAINLY THE CENTRAL AND ERN ZNS THIS EVNG...EXPECT AT LEAST ISOLD -SHRA TO DRIFT THRU THIS AREA...MAINLY NEAR THE GREEN BAY/LK MI. LATER TNGT AFT THE SHRTWV DRIFTS TO THE NE OF UPR MI AND HGTS BEGIN TO RISE UNDER THE DNVA/VIGOROUS DEEP LYR QVECTOR DVGC IN THE WAKE OF THIS DISTURBANCE...EXPECT A DRYING TREND ALF AND FOR ANY PCPN TO END W-E. BUT LO CLDS AND SOME FOG WL BE AROUND WITH LINGERING LLVL MSTR AND ONLY WEAK HI PRES SHIFTING OVHD. WITH THE LINGERING LO CLDS...TEMPS SHOULD FALL ONLY A COUPLE OF DEGREES. WED...UNDER RISING HGTS/DEEP LYR QVECTOR DVGC UNDER SHRTWV RDGING ALF...EXPECT MID LVL DRYING AS AIRMASS NOW MOVING THRU THE NRN PLAINS SHIFTS INTO THE UPR LKS. ALTHOUGH LO CLDS/SOME FOG WL LINGER THRU SUNRISE...DIURNAL HEATING/MIXING SHOULD TEND TO BREAK UP THIS LO CLD. SHARP SUBSIDENCE INVRN SHOWN ON FCST SDNGS BTWN H75-8 AND LLVL ACYC FLOW WL TEND TO SQUASH ANY CONVECTION THAT MIGHT TRY TO FIRE WITH DAYTIME HEATING/MORE HUMID LLVL AIRMASS THAT WL SUPPORT SFC DEWPTS WELL INTO THE 50S. IN FACT...NAM/ GFS FCST SDNGS SHOW CONVECTIVE TEMP AOA 90. MIXING TO H8-85 ON THESE FCST SDNGS HINT MAX TEMPS WL REACH ARND 80 AWAY FM LK MODERATION. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 352 PM EDT TUE MAY 28 2013 WARM AND ACTIVE WEATHER PATTERN EXPECTED TO CONTINUE THROUGH MUCH OF THE WEEKEND. FOG WILL ALSO BE PROBLEMATIC OVER THE GREAT LAKES AS WARMER AIR MOVES INTO THE AREA ENHANCING THE MARINE LAYER. THIS...COUPLED WITH RAIN FALLING INTO THE MARINE LAYER...WILL INCREASE THE MOISTURE TRAPPED IN THE MARINE LAYER AIDING IN FOG FORMATION. THE FOG IS EXPECTED TO MIX OUT BY THE LAST HALF OF THE WEEKEND AS COOLER AIR MOVES IN ALOFT AND DRY AIR SPILLS OUT OF CANADA INTO THE UPPER GREAT LAKES REGION. WEDNESDAY NIGHT THROUGH THURSDAY...A WARM FRONT...EXTENDING FROM SOUTHERN MN EASTWARD INTO CENTRAL WI AND CENTRAL LOWER MI WEDNESDAY AFTERNOON...WILL LIFT NORTHWARD INTO THE UPPER MICHIGAN BETWEEN 00Z AND 06Z WEDNESDAY NIGHT AS SHOWN BY OVERLAYING 850MB THETA E ALONG WITH 850MB WINDS. THIS HAPPENS AROUND THE SAME TIME THAT HEIGHT FALLS...ASSOCIATED WITH THE SURFACE LOW AND UPPER LEVEL 500MB LOW OVER THE WEST HALF OF THE UNITED STATES...BEGIN TO SHIFT EASTWARD INTO THE WESTERN UPPER PENINSULA. MOISTURE TRANSPORT INTO THE REGION...ALONG WITH CONVERGENCE ALONG THE NOSE OF THE 850MB LLJ LIFTING NORTHWARD INTO SOUTHEASTERN MN AND WESTERN WI...WILL BE FAVORABLE FOR SHOWER AND THUNDERSTORM DEVELOPMENT. CAPE VALUES DURING THIS TIME ARE PROGGED TO BE BETWEEN 500 J/KG AND 1000 J/KG WITH THE NAM BEING ON THE HIGHER END AND MANY OF THE OTHER MODELS AROUND 500-600 J/KG. WHILE INSTABILITY VALUES ARE FAVORABLE FOR THUNDERSTORM DEVELOPMENT...THE CHANCES OF SVR WEATHER AT THIS POINT ARE LIMITED AS BULK SHEAR VALUES WOULD BE MARGINAL...RANGING FROM 20 TO 25 KTS. FOR A MORE ORGANIZED SVR WEATHER THREAT...BULK SHEAR VALUES WOULD NEED TO BE CLOSER TO 40-45 KNOTS OR GREATER. THURSDAY NIGHT THROUGH FRIDAY...THE UPPER LEVEL LOW WILL REMAIN NEARLY STATIONARY OVER THE NORTHERN PLAINS THROUGH THIS TIME PERIOD. THE MAIN ISSUE WILL BE A SHORTWAVE PROGGED TO ROTATE AROUND THIS UPPER LEVEL LOW AS THE SURFACE LOW SHIFTS INTO NORTHERN MN. EXACT TIMING AND STRENGTH OF THE SHORTWAVE DIFFER FROM MODEL TO MODEL WITH THE GFS STILL TRYING TO BRING A MUCH MORE AGGRESSIVE SHORTWAVE INTO THE AREA. CURRENT TRENDS ARE SHOWING THAT THE SHORTWAVE OVER THE PLAINS STATES THURSDAY NIGHT WILL ROTATE NORTHEASTWARD...REACHING THE U.P. BY LATE MORNING TO EARLY AFTERNOON FRIDAY. CONFIDENCE IN INTENSITY AND TIMING OF THE SHORTWAVE IS FAIRLY LOW AS THESE THINGS ARE HIGHLY DEPENDENT UPON CONVECTIVE DEVELOPMENT. FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE SURFACE LOW WILL SHIFT FROM NORTHERN MN FRIDAY NIGHT INTO UPPER MI SATURDAY AND INTO LOWER MI SATURDAY NIGHT. AT THE SAME TIME THE UPPER LEVEL 500MB TROUGH WILL SHIFT FROM NORTHERN MN INTO UPPER MI. THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER UPPER MI INTO SATURDAY AFTERNOON...BEFORE THE SURFACE LOW SHIFTS INTO NORTHERN LOWER MI. ON THE BACK SIDE OF THE SURFACE LOW SATURDAY EVENING...THE CHANCES FOR THUNDERSTORM ACTIVITY WILL DIMINISH GREATLY...HOWEVER...THE CHANCE FOR SHOWERS WILL REMAIN IN THE FORECAST AS THE UPPER LEVEL TROUGH MOVES OVERHEAD. SUNDAY AND SUNDAY NIGHT...THE 500MB TROUGH OVER THE UPPER PENINSULA WILL SHIFT SLOWLY EASTWARD THROUGH SUNDAY NIGHT ALLOWING THE CHANCE OF SHOWERS TO SLOWLY DIMINISH THROUGH SUNDAY EVENING. THE 06Z AND 12Z GFS STILL REMAINS THE OUTLIER AS IT TRIES TO PULL DRY AIR FROM CANADA INTO THE UPPER PENINSULA TOO QUICKLY...AROUND 18Z...WHILE THE EC/GEM KEEP THE MOISTURE IN PLACE THROUGH 00Z-06Z. THE NEW 06Z RUN OF THE GFS TRENDED CLOSER TO THE EC/GEM...THEREFORE WILL HANG ON TO CLOUD COVER AND CHANCE OF SHOWERS INTO EARLY SUNDAY EVENING. MONDAY THROUGH TUESDAY...A BROAD SURFACE HIGH PRESSURE SYSTEM AND UPPER LEVEL 500MB RIDGE WILL BUILD FROM NEAR HUDSON BAY SOUTHWARD INTO MUCH OF THE UPPER MISSISSIPPI VALLEY THROUGH MONDAY NIGHT...ALLOWING FOR COOL AND DRY WEATHER TO BUILD INTO THE REGION. AT THE SAME TIME AN UPPER LEVEL TROUGH IS PROGGED TO FORM OVER WESTERN CANADA. THE GFS/EC AGAIN HAVE INTENSITY AND PLACEMENT ISSUES FOR THIS LOW...WITH THE GFS STRONGER AND MORE PROGRESSIVE...PLACING THE THROUGH OVER THE UPPER PENINSULA BY LATE TUESDAY MORNING. THE EC KEEPS THE TROUGH TO THE WEST OF THE AREA...OVER THE NORTHERN PLAINS...THROUGH TUESDAY EVENING. WITH LOWER THAN NORMAL CONFIDENCE...WILL STICK WITH MODEL CONSENSUS FOR THIS TIME FRAME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 122 PM EDT TUE MAY 28 2013 WITH ABUNDANT SFC-H75 MSTR SHOWN ON THE 12Z MPX/GRB/APX RAOBS IN ADVANCE OF SFC WARM FNT IN THE LOWER GRT LKS MOVING SLOWLY TO THE N...EXPECT SLOWLY DETERIORATING CONDITIONS AT THE TAF SITES THRU TNGT...ESPECIALLY IN THE PRESENCE OF DIURNAL COOLING. IFR CONDITIONS ARE POSSIBLE AT ALL 3 SITES BEFORE DAYTIME HEATING/MIXING ON WED RESULT IN SOME IMPROVEMENT AS WEAK SFC HI PRES MOVES INTO THE AREA. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 352 PM EDT TUE MAY 28 2013 WITH GENERALLY WEAK PRES GRADIENT AND STABLE CONDITIONS OVER LAKE SUPERIOR...EXPECT WINDS TO BE UNDER 25KT THRU THE WEEK. ALTHOUGH SOME FOG MAY DEVELOP LATE TONIGHT OVER THE LAKE WITH GRADUALLY INCREASING LOW LEVEL MOISTURE...THICKER AND MORE WIDESPREAD FOG IS NOT LIKELY UNTIL SOME APPRECIABLE RAINFALL OCCURS OVER THE LAKE...PROBABLY NOT UNTIL WED NIGHT. AT LEAST PATCHY DENSE FOG IS THEN LIKELY INTO SAT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KEC AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
127 PM CDT WED MAY 29 2013 .UPDATE... 18Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 400 AM CDT WED MAY 29 2013 A VERY VOLATILE WATER VAPOR IMAGE AND H5 PATTERN IS IN PLACE THIS MORNING AS A NEGATIVELY TILTED TROUGH SITS FROM NEAR YELLOW STONE SOUTHEAST TO THE BIG BEND REGION OF TEXAS. CONVECTION ACROSS THE PLAINS YESTERDAY AND OVERNIGHT HAS LEFT MULTIPLE SHORT WAVES/MCVS LITTERED ACROSS NATIONS MIDSECTION. DURING THE DAY...THE MAIN TROUGH WILL MIGRATE E/NE ACROSS THE PLAINS...AND BY THE END OF THE PERIOD THE TROUGH WILL STRETCH FROM A DEVELOPING CLOSED LOW OVER THE BLACK HILLS SOUTHEAST TOWARD NE TEXAS. AT 330 AM...THE WARM WAS JUST PASSING THROUGH FORT DODGE IN IOWA AND HAS ACTUALLY BEGUN TO PICK UP SOME MOMENTUM TOWARD THE NORTH IN THE LAST FEW HOURS. BASED ON THE RAP...THIS BOUNDARY WILL BE NEAR I-90 AT 15Z...BY 18Z IT SHOULD BE WORKING ITS WAY THROUGH THE TWIN CITIES BEFORE BECOMING STATIONARY AT 00Z FROM A SFC LOW OVER NORTH CENTRAL NEB...NORTHEAST THROUGH ABERDEEN AND UP TOWARD LAKE OF THE WOODS. FOR THIS FORECAST...FAVORED A NAM/ECMWF BLEND FOR HANDLING OF LARGE SCALE FEATURES SUCH AS SHORTWAVES AND THE LLJ...WHILE A BLEND OF THE HI-RES CAMS WERE USED TO TRY AND ADD DETAIL TO THE POP FORECAST. BASED ON THAT...WHAT FOLLOWS IS THE CURRENT THINKING IS OF 330 AM FOR WHAT WILL HAPPEN TODAY. FOR THE WARM FRONT COMING NORTH...IS LOOKING LIKE CONVECTIVE ACTIVITY WILL BE SCATTERED IN NATURE...AS H85 LLJ IS ACTUALLY SOMEWHAT DIFFLUENT OVER MN...WITH ONE BRANCH SPLITTING OF FROM IOWA INTO SODAK...WITH THE REST OF THE JET FANNING OUT TOWARD THE NE ACROSS MN INTO WI. THE HRRR AND OTHER CAMS ALONG WITH THE RAP IS SHOWING A BATCH OF ELEVATED SHOWERS AND STORMS DEVELOPING EARLY THIS MORNING NORTH OF THE BOUNDARY AND HEADING TOWARD SE MN BY THE EARLY AFTERNOON. THIS SEEMS TO BE IN RESPONSE TO A SHORTWAVE NOTED ON WATER VAPOR CURRENTLY WEST OF OMAHA THAT THE RAP DRAGS NE TOWARD SE MN THROUGH THE MORNING. THE HRRR IS BY FAR THE MOST AGGRESSIVE WITH THIS CONVECTION AT THE MOMENT...BUT OUTSIDE OF SOME POTENTIAL FOR HAIL...THE SEVERE THREAT LOOKS LIMITED WITH THIS BATCH OF CONVECTION...IF IT DOES FORM. FOR THE SEVERE THREAT...ATTENTION REALLY TURNS TO ERN SODAK/WRN MN THIS AFTERNOON. WITH THE NAM/ECMWF SHOWING THE LLJ ANGLING BACK NW INTO SODAK IN RESPONSE TO HEIGHT FALLS ALOFT...THIS SHOULD LEAD TO THE INITIATION OF MORE SURFACE BASED CONVECTION SOMEWHERE NEAR THE RETREATING WARM FRONT IN ERN SODAK/WRN MN. FORECAST SOUNDINGS FROM THE RAP/NAM SHOW ATMO REMAINING CAPPED ACROSS WRN MN UNTIL ABOUT 21Z...AT WHICH POINT YOU ARE DEALING WITH AROUND 1500 J/KG OF SBCAPE IN A WEAKLY CAPPED...STRONGLY SHEARED /ESPECIALLY IN THE LOWEST 3 KM/ ENVIRONMENT. NMM/ARW BASED CAMS SHOW LITTLE CONVECTION DEVELOPING THROUGH 21Z...BUT QUICKLY GENERATE CONVECTION AFTER 21Z...SO WAITED TO INTRODUCE ANY LIKELY POPS UNTIL 21Z. SEEING TWO CAMPS IN THE CAMS FOR HOW CONVECTION DEVELOPS THIS AFTERNOON...WITH THE ARW AND NSSL-WRF GENERATING STORMS OVER WRN MN...WHILE THE NMM AND SPCWRF GENERATE CONVECTION OVER ERN SODAK. THIS IDEA FOR ACTIVITY STARTING OUT WEST THIS AFTERNOON IS FURTHER SUPPORTED BY THE SPC SSEO...WHICH SHOWS NEIGHBORHOOD PROBABILITIES FOR UPDRAFT HELICITY AND UPDRAFT STRENGTH BEING MAXIMIZED OVER ERN SODAK INTO WRN MN...WITH VERY LITTLE ACTIVITY BEING NOTED FROM SRN INTO ERN MN AND WRN WI THIS AFTERNOON. GIVEN DEGREE OF LOW LEVEL SHEAR...THERE WILL BE THE THREAT FOR TORNADIC ACTIVITY WHILE THE STORMS AREA DISCRETE...BUT DO EXPECT STORMS THIS AFTERNOON TO GROW UPSCALE...WITH A HAIL/WIND THREAT CONTINUING INTO THE NIGHT. FOR TONIGHT...WHAT HAPPENS WITH CONVECTION THIS AFTERNOON WILL PLAY A LARGE ROLE IN WHAT HAPPENS TONIGHT. WITHIN THE CAMS...WE ARE AGAIN LOOKING AT TWO CAMPS. THE NMM AND SPCWRF DO NOT BRING THE DAKOTA CONVECTION INTO MN...WHILE SENDING ANOTHER MCS RACING ACROSS IOWA...KEEPING MUCH OF THE MPX CWA DRY. THE ARW AND NSSL-WRF CONGEAL THE AFTERNOON CELLS IN THE WEST INTO A LINE...AND TRACK THAT COMPLEX OF STORMS EAST ACROSS THE STATE THROUGH THE NIGHT. GIVEN EXPECTED EVOLUTION OF THE LLJ FROM THE ECMWF/NAM...FAVOR THE ARW/NSSL-WRF CAMP...WITH A COMPLEX OF STORMS WORKING EAST ACROSS THE AREA THROUGH THE NIGHT...WITH CONVECTIVE COVERAGE AND INTENSITY SLOWLY DIMINISHING AFTER 6Z. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 400 AM CDT WED MAY 29 2013 CUTOFF UPPER CIRCULATION DEVELOPS AND LINGERS ACROSS THE HIGH PLAINS AND WESTERN GREAT LAKES INTO THE COMING WEEKEND. AS THE UPPER LOW TAKES FORM OVER THE NORTHERN PLAINS THROUGH THURSDAY... A BELT OF FASTER WESTERLY FLOW ASSOCIATED WITH A SHORT WAVE TROUGH WILL MOVE EAST FROM THE CENTRAL PLAINS TO THE MIDWEST. CLOUDS WILL REMAIN ABUNDANT OVER THE REGION...AND WILL LIMIT SIGNIFICANT DESTABILIZATION. HOWEVER...LARGE SCALE ASCENT FROM THE INCOMING SHORT WAVE AND STEEPENING MID LEVEL LAPSE WILL LIKELY SUPPORT SOME STRONG TO SEVERE STORMS ACROSS CENTRAL AND SOUTHERN MINNESOTA THURSDAY AFTERNOON AND THURSDAY NIGHT. THE SURFACE LOW WILL DEEPEN AND OCCLUDE IN EASTERN NORTH DAKOTA INTO THURSDAY NIGHT...AND WILL HELP PUSH THE COLD FRONT EAST INTO CENTRAL MINNESOTA. WE SHOULD SEE HIGH POPS INTO THURSDAY AFTERNOON AS THIS SYSTEM MOVES THROUGH...AND MAINLY OVER EASTERN AREAS INTO THURSDAY NIGHT AHEAD OF COLD FRONT. HAIL AND STRONG WINDS WILL BE THE MAIN THREATS...ALONG WITH HEAVY RAIN. WILL TRAIL POPS OFF TO THE WEST DURING THE AFTERNOON. THE 00Z ECMWF IS MOST CONSISTENT WITH DRIVING A DRY SLOT NORTHEAST OVER THE AREA INTO FRIDAY...LIMITING SIGNIFICANT CONVECTION FURTHER EAST IN THE REMNANT WARM SECTOR INTO WESTERN WISCONSIN. THIS WILL LIMIT SEVERE WEATHER DEVELOPMENT ON FRIDAY...WITH THE DAY 3 OUTLOOK MAINLY SOUTHEAST OF OUR CWA. SYSTEM SLOW TO MOVE THROUGH THE AREA...WITH COLD AIR CIRCULATING OVER THE REGION WELL INTO THE WEEKEND. EXPECTING DRIER CONDITIONS DEVELOPING SATURDAY NIGHT AND LINGERING INTO MONDAY. TEMPERATURES WILL RANGE SOME 5 TO 10 DEGREES BELOW AVERAGE THROUGH THE PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 130 PM CDT WED MAY 29 2013 SHOWERS AND THUNDERSTORMS WILL BECOME MORE NUMEROUS ACROSS THE TAF AREA THIS AFTERNOON AND EVENING. ANY STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO CAUSE SOME GUSTY WINDS...HAIL..AND IFR CONDITIONS. SHOULD SEE A LULL IN ACTIVITY OVERNIGHT...WITH REDEVELOPMENT EXPECTED THURSDAY. IN THE MEANTIME...BKN MVFR LEVEL CLOUDS WILL SCATTER OUT BRIEFLY THIS AFTERNOON...BUT NOT TOTALLY SCOUR OUT BEFORE THE CONVECTION OVERSPREADS THE AREA. WINDS WILL BE PREVALENT OUT OF THE SOUTHEAST...WITH DIURNAL GUSTING TODAY AND THURSDAY. KMSP... MVFR DECK WILL BE MORE OF A SCATTERED NATURE THIS AFTERNOON...BUT COULD BECOME BROKEN BELOW 1700 FT WITH SHOWERS/THUNDERSTORMS THIS AFTERNOON/EVE. THUNDERSTORMS ARE EXPECTED TO ARRIVE AROUND 21Z...THEN INTERMITTENTLY PERSIST UNTIL DARK. SHOULD SEE A LULL OVERNIGHT...THEN ADDITIONAL ACTIVITY BY THURSDAY AFTERNOON. /OUTLOOK FOR KMSP/ THU...MVFR OR LOWER CIGS LIKELY. SHRA/TSRA LIKELY. WINDS S 15-20 KTS. FRI...MVFR OR LOWER CIGS LIKELY. CHANCE SHRA/TSRA. WINDS SW 10-15 KTS. SAT...MVFR CIGS POSSIBLE. CHANCE SHRA/TSRA. WINDS WNW 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...DWE AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
145 AM CDT TUE MAY 28 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 400 PM CDT MON MAY 27 2013 PERSISTENT AREA OF LIGHT SHOWERS AND DRIZZLE NOTED SOUTH OF A LINE FROM KMSP TO KEAU AND EAST OF LINE FROM SHAKOPEE TO TRUMAN. THIS REGION IS REMNANTS OF MCS WHICH FORMED OVER NORTHERN IOWA DURING THE OVERNIGHT. AREA CORRELATES WELL WITH GFS40 THETA E ADVECTION. CURRENT HRRR ALSO SEEMS TO HAVE A GOOD HANDLE OF AREAL COVERAGE AND INTENSITY. REGION WAS STRUGGLING EARLIER THIS AFTERNOON AS IT MARCHED NORTH INTO DRIER AIR COLUMN AND CONVERGENCE DEPICTED AT 250MB. EXPECT CONTINUED SLOW MIGRATION OF PRECIPITATION SHIELD NORTH AS LATE DAY SURFACE HEATING CONTINUES TO MAINTAIN OR SLOWLY ENHANCE CURRENT INTENSITY. LOOK FOR CESSATION OF MOST PRECIP. FROM THIS FEATURE BY AROUND 28/06Z. FOR THE REMAINDER OF THE OVERNIGHT EXPECT ANOTHER LATE NIGHT MCS TO FOLLOW THE PLACEMENT OF A WARM FRONTAL BOUNDARY ABOVE CENTRAL TO NORTHERN IOWA. MCS WILL AGAIN FORM OVER EASTERN SODAK AND FOLLOW 1000-500MB THICKNESS LINE DROPPING ANOTHER THREE QUARTERS TO ONE INCH OF RAINFALL OVER PORTIONS OF CENTRAL TO NORTHERN IOWA. SHOULD BE ANOTHER RATHER GLANCING BLOW FOR THE FAR SW AND SOUTH CENTRAL PORTION OF THE MN CWA...SIMILAR TO THE PREVIOUS THREE NIGHTS...WITH A FEW TENTHS TO POSSIBLY FOUR TENTHS OF AN INCH EXPECTED OVER THIS REGION...WITH HEAVIEST AMOUNTS OVER FAR SOUTH CENTRAL MINNESOTA. MCS OVER NORTHERN IOWA SHOULD FOLLOW SAME TRAJECTORY AS TODAY`S PCPN SHIELD...WITH POSSIBLY A FEW MORE EMBEDDED THUNDERSTORMS AS LI`S GRADUALLY RECEDE INTO NEGATIVE TERRITORY. MOISTURE FROM THIS SYSTEM WILL AGAIN BE ON THE WEAK SIDE...WITH MAINLY AROUND ONE TENTH OF AN INCH ON AVERAGE ANTICIPATED PRIOR TO PASSAGE. USED A BLEND BETWEEN NAM AND GFS40 FOR TUESDAY`S HIGH TEMPERATURES ...AND THEN THROTTLED BACK ONE CATEGORY. OF COURSE INTENSITY AND FORWARD SPEED OF RAINFALL SHIELD MENTIONED ABOVE WILL DETERMINE WHETHER TEMPERATURES NEED TO BE CUT EVEN FURTHER. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 400 PM CDT MON MAY 27 2013 TUESDAY EVENING INTO WEDNESDAY MORNING IS EXPECTED TO BE A DRY TIME FRAME...AS THE SURFACE WARM FRONT REMAINS TO THE SOUTH OVER SOUTHERN IOWA AND THE LOW LEVEL MOISTURE/WARM AIR ADVECTION IS FOCUSED THERE AS WELL. HOWEVER...SHOWERS AND THUNDERSTORMS SHOULD OVERSPREAD THE AREA DURING THE DAY ON WEDNESDAY...AS THE WESTERN TROUGH SURGES EASTWARD...AND THE FRONT AND ADVECTION PROCESSES SHIFT NORTHWARD IN CONJUNCTION WITH A SHORTWAVE IMPULSE. STRONGLY DIFFLUENT FLOW ALOFT COMBINES WITH THE LOW LEVEL JET INFLUENCES...AND COULD SET THE STAGE FOR A FEW SEVERE STORMS ON WEDNESDAY AFTERNOON/EVE. ON THURSDAY...THE UPPER TROUGH TAKES ON A NEGATIVE TILT...AS THE WARM FRONT LIFTS ACROSS THE AREA. THIS WILL CONTINUE THE SEVERE WEATHER THREAT AND ENHANCE THE FLOODING POTENTIAL AS WELL. PWATS WILL REMAIN NEAR CLIMATOLOGICAL RECORD VALUES /1.5 TO 2.0 INCHES/...WHILE THE TROUGH STRUCTURE PROVIDES THE SHEAR SUFFICIENT FOR STRONG POSSIBLY SEVERE STORMS. ON FRIDAY...THE COLD FRONTAL BOUNDARY ASSOCIATED WITH THE SURFACE LOW PASSES ACROSS THE AREA...AND CONTINUES THE THREAT FOR WIDESPREAD SHOWERS AND THUNDERSTORMS. ALTHOUGH THE THREAT FOR SEVERE STORMS WILL DIMINISH ON SATURDAY IN THE WAKE OF THE SURFACE LOW...RAIN SHOWERS WILL CONTINUE TO BE POSSIBLE OVER THE WEEKEND AS THE MID/UPPER TROUGH ROTATES OVER THE UPPER MIDWEST. HIGH TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY ABOVE NORMAL FOR THE END OF MAY...RANGING THROUGH THE MID TO UPPER 70S...AND THEN DECLINE TO AROUND 5 TO 10 DEGREES BELOW NORMAL FOR THE FIRST FEW DAYS IN JUNE /65 TO 70 DEGREES/. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1049 PM CDT MON MAY 27 2013 ALL SITES INITIALIZED AT MVFR WITH IFR CIGS NOT ALL THAT FAR OFF. AREA OF -SHRA/-DZ OVER WRN WI CONTINUES TO SHRINK... EVENTUALLY SHUTTING OFF BY ABOUT 08Z-09Z. AS WINDS DIMINISH A BIT AND PRECIP ENDS...CIGS WILL LOWER INTO IFR RANGE FOR MUCH OF THE NIGHT. A WINDOW FOR PRECIP TO RETURN LOOKS MOST EVIDENT BETWEEN 10Z-16Z TMRW IN MN...AND A FEW HRS LATER IN WI...AND HAVE PLAYED THE TAFS AS SUCH. PRECIP ITSELF WILL BE MAINLY VFR WITH POSSIBLY SOME HEAVIER SHOWERS PRODUCING MVFR VSBY. SHOWERS LOOK TO END ARND 18Z- 20Z...WITH IMPROVING CONDS AFTERWARDS. NOT EXPECTING ANY CB/TS THRU TMRW. WINDS WILL BE MAINLY SE THRU THE NIGHT...THEN SOME LGT/VRBL WINDS WILL DEVELOP MID-TO-LATE DAY TMRW BEFORE WINDS SWING SW. KMSP...INITIALIZED JUST ABOVE IFR CIGS BUT AM EXPECTING CIGS TO DROP BELOW 1 KFT BEFORE TOO LONG AND THEN TO REMAIN THERE THROUGH THE REST OF THE OVERNIGHT HRS. WINDS LOOK TO REMAIN UP JUST ENOUGH TO PREVENT FOG FORMATION. A WINDOW OF PRECIP EXPECTED TO DEVELOP BETWEEN 14Z-20Z FOR KMSP AND HAVE RUN WITH MVFR VSBY DURG THIS TIME. THAT MAY BE A BIT PESSIMISTIC SO THIS CAN BE ADJUSTED IF NECESSARY. CONDS IMPROVE BY LATE TMRW AFTN TO VFR FOR BOTH CIG/VSBY AND WILL REMAIN AS SUCH THRU TMRW EVE. WINDS REMAIN MAINLY SE THRU THE PERIOD...BUT GO LGT/VRBL TMRW AFTN BEFORE SHIFTING TO S AND SE TMRW EVE. /OUTLOOK FOR KMSP/ WED...MVFR OR LOWER CIGS LIKELY...MAINLY IN THE AFTN. SHRA/TSRA LIKELY... MAINLY IN THE AFTN. WINDS S 10-15 KT. THU...MVFR OR LOWER CIGS LIKELY. SHRA/TSRA LIKELY. WINDS S 15-20 KT. FRI...MVFR OR LOWER CIGS LIKELY. SHRA/TSRA LIKELY. WINDS SW 10-15 KT. && .HYDROLOGY... ISSUED AT 144 AM CDT TUE MAY 28 2013 SO FAR THE MPX CWA HAS LUCKED OUT THE LAST SEVERAL DAYS...AS HEAVY RAINS HAVE REMAINED CONFINED TO IOWA. THIS LOOKS REMAIN THE CASE THROUGH TUESDAY NIGHT. HOWEVER...WEDNESDAY WILL SEE THE UPPER RIDGE OVER THE EAST COAST STRENGTHEN AND BUILD INTO THE GREAT LAKES WHILE A POTENT TROUGH OVER THE ROCKIES BEGINS WORKING OUT INTO THE PLAINS. THIS WILL FINALLY HELP PUSH THE WARM FRONT NORTH ON WEDNESDAY. PWATS FROM THE NAM/GFS ARE FORECAST TO BE UP AROUND THE CLIMATOLOGICAL RECORD FOR MAY WEDNESDAY INTO THURSDAY...WITH A STRONG AND MOISTURE LADEN LLJ FORECAST TO COME UP INTO MN ON WEDNESDAY AND SLOWLY WORK INTO WI THROUGH THURSDAY. THIS WILL RESULT IN THE TREAT FOR HEAVY RAINS WEDNESDAY THROUGH THURSDAY NIGHT ACROSS THE MPX CWA. IN PARTICULAR...AREAS AROUND SE MN INTO WRN WI WILL HAVE THE HIGHEST THREAT FOR FLOODING DUE BOTH TO RECENT WETNESS AND THE FACT THAT THESE AREAS WILL BE SPENDING THE LONGEST AMOUNT OF TIME WITHIN THE GULF MOISTURE FEED. STILL LOTS OF UNCERTAINTY AS TO TIMING AND EXACT PLACEMENT OF SFC FEATURES...BUT WE COULD SEE SEVERAL ROUNDS OF THUNDERSTORMS WEDNESDAY THROUGH THURSDAY NIGHT THAT COULD RESULT IN TOTAL RAINFALL AMOUNTS BETWEEN 2 AND 4 INCHES WITH LOCALLY HIGHER AMOUNTS. GIVEN UNCERTAINTIES...AND RECENT BIAS IN DETERMINISTIC MODELS TO FORECAST TOO MUCH QPF MAKING IT UP INTO THE MPX CWA IN RECENT DAYS...HAVE CONTINUED TO HOLD OFF ON ISSUING ANY SORT OF FLOOD WATCH. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...AJZ LONG TERM...LS AVIATION...JPC HYDROLOGY...MPG
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
249 PM CDT TUE MAY 28 2013 .DISCUSSION... CONVECTION/POSSIBLE FLOODING THROUGH THURSDAY REMAINS PRIMARY CONCERN. SUBJECTIVELY PLACED QUASI-STATIONARY FRONT EXTENDED FROM FAR SERN NEBR INTO SWRN IA AT 19Z WITH CU FIELD THICKENING NEAR/SOUTH OF IT...ALTHOUGH VIEW SOMEWHAT HINDERED BY HIGHER CLOUDS. ALTHOUGH FIRST AREA OF CONVECTION WAS DEVELOPING SE OF THE REGION...AND LEADS SOME SMALL DOUBTS TO WHAT MAY HAPPEN FARTHER NW...VARIOUS MODEL QPF INCLUDING RAP/HRRR AND 4KM WRF DVLP PRECIP OVER SERN ZONES THROUGH EARLY EVENING. THIS LOOKS REASONABLE GIVE LATEST SPC RUC MESO ANALYSIS PAGE SHOWED SRN ZONES ON EDGE OF ML CAPE AXIS OF 3000-4000 J/KG WITH WEAKENED/NO CAP. LOW LEVEL/DEEPER SHEAR FAVORABLE FOR SEVERE WEATHER...SEE LATEST WATCH/MCD FOR INFO ON THIS. SINCE SRN ZONES RECEIVED 1-2+ INCHES OF RAIN LAST EVENING... RIVERS/STREAMS ARE RUNNING HIGH OR CLOSE TO FLOODING IN SOME CASES. WITH FFG VALUES UNDER 2 INCHES...OPTED TO ISSUE A FLASH FLOOD WATCH SERN COUNTIES THROUGH TONIGHT. EXTENDED WATCH TO NEBR CITY/4 SW IA COUNTIES IN CASE STRENGTHENING LOW LEVEL JET ALLOWS ACTIVITY TO SPREAD/DEVELOP N LATER THIS EVENING...BUT IT WAS NOTED THAT 4KM WRF AND HRRR DROPPED CONVECTION SE THRU EARLY EVENING. OTHERWISE ADJUSTED POPS NRN ZONES TONIGHT TO REFLECT BETTER CHANCES LATER TONIGHT AS LOW LEVEL JET STRENGTHENS N ACROSS THE AREA CLOSER TO AND AFTER 06Z. DIURNALLY DECREASED POPS THRU MIDDAY WEDNESDAY BEFORE STRONGER UPPER TROUGH BEGINS CRASHING UPPER HGTS INTO CNTRL NEBR. THIS COULD ALLOW A LITTLE EARLIER CONVECTIVE DEVELOPMENT...IF IT EVEN DECREASES...AND COULD ALSO SET THE STAGE FOR A SEVERE WEATHER AND HEAVY RAIN THREAT OVER A LARGER PART OF THE FORECAST AREA. WITH TRAINING POSSIBLE AS UPPER FLOW BECOMES MORE PARALLEL TO MEAN SHEAR VECTORS THRU WED EVENING...TRAINING OF ECHOES COULD ADD TO FLOODING POTENTIAL. THIS MAY NECESSITATE A FLASH FLOOD WATCH OVER A LARGER PART OF THE AREA FOR LATE WED/WED NIGHT IN LATER FORECASTS...BUT FOR NOW FIRST FLASH FLOOD WATCH WILL ADDRESS SHORTER TERM FLOODING THREAT. ACTIVE WEATHER COULD PERSIST INTO THURSDAY AS JET WRAPS ACROSS SRN ZONES ON SOUTH END OF CLOSING UPPER LOW. QUESTION WILL THEN SHIFT TO AMOUNT OF RESIDUAL MOISTURE THAT WILL REMAIN OVER AREA AS UPPER TEMPS COOL BUT SURFACE WINDS TAKE ON A MORE WRLY... DOWNSLOPE...COMPONENT. FOR NOW MADE LITTLE/NO CHANGES TO PREVIOUS FORECAST POPS...WHICH WERE FAIRLY HIGH YET THROUGH THU EVENING...BUT LOWERED LATE THU NGT. NO CHANGES MADE TO MODEST POPS FRIDAY OR REST OF MODEL/PRIOR FORECAST BLEND REST OF FORECAST. SOME POTENTIAL FOR TEMPERATURES TO REALLY WARM TOMORROW AS SRLY WINDS INCREASE AHEAD OF TROUGH AND WITH WRLY COMPONENT TO SURFACE WINDS ON THURSDAY. HOWEVER...WITH RISK/UNCERTAINTY OF RESIDUAL CLOUDS AND OR TSTMS...OPTED FOR LITTLE CHANGE FROM PREVIOUS FORECAST WHICH WAS FAIRLY ALIGNED WITH GUIDANCE. && .AVIATION... 18Z TAFS FOR KOFK...KOMA AND KLNK. VFR AT ALL THREE TAF SITES FOR THE TIME BEING. WILL TREND BACK INTO MVFR PRIMARILY WITH VSBYS GOING DOWN TO INTO THE 4SM CATEGORY AFTER 10Z. AT KLNK AND KOMA HAVE ALSO BROUGHT IN TEMPO FOR -TSRA WITH IFR CIGS AND VSBY STARTING AT THAT SAME 10Z TIME PERIOD. HAVE KEPT THUNDER OUT OF KOFK TAF FOR NOW THINKING THAT MOST ACTIVITY WILL DEVELOP ALONG SOMEWHAT OF STALLED OUT SURFACE BOUNDARY EXTENDING ACROSS BOTH THE KOMA AND KLNK TAF SITES. EXPECT THUNDERSTORMS TO END OR MOVE EAST OF AREA AFTER 16Z WITH ANOTHER SHORT REPRIEVE BEFORE REDEVELOPMENT AGAIN INTO LATER FORECAST PERIODS. OVERALL A VERY ACTIVE PATTER WILL CONTINUE FOR THE NEXT SEVERAL DAYS. MEYER && .HYDROLOGY...UPDATED AT 110 PM CDT... FOR INFO ON FLASH FLOOD WATCH SEE ABOVE. OTHERWISE FLOOD WARNING CONTINUES FOR TURKEY CREEK AT WILBER. THOUGH IT HAS CRESTED AND STARTED FALLING FOR NOW...IT IS FORECAST TO RISE AGAIN LATER TONIGHT AND WEDNESDAY. THE LITTLE AND BIG NEMAHA RIVERS IN SOUTHEAST NEBRASKA DID RISE TO JUST BELOW FLOOD STAGE BUT HAVE SINCE STARTED TO DECLINE. WARNINGS ALSO CONTINUE FOR THE MISSOURI RIVER FROM PLATTSMOUTH DOWNSTREAM TO RULO FOR SIGNIFICANT RISES OVER THE NEXT FEW DAYS. OMAHA ON THE MISSOURI RIVER IS FORECAST TO RISE...BUT REMAIN JUST BELOW FLOOD LEVELS BUT WILL EVENTUALLY NEED A FLOOD ADVISORY. THE NISHNABOTNA RIVER BASIN DID ALSO SEE SIGNIFICANT IN BANK RISES...BUT REMAINED BELOW FLOOD STAGE AND HAVE STARTED TO FALL. A FLOOD WARNING WAS ISSUED ON THE LITTLE SIOUX RIVER NEAR TURIN AS IT IS FORECAST TO GO ABOUT TWO FEET ABOVE FLOOD STAGE BY FRIDAY. MEYER && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS ELKO NV
1054 AM PDT TUE MAY 28 2013 .SYNOPSIS...A LOW PRESSURE SYSTEM WILL BRING SCATTERED SHOWERS TO MAINLY EASTERN NEVADA THIS AFTERNOON AND EARLY EVENING. ANOTHER LOW PRESSURE SYSTEM WILL BRING SCATTERED SHOWERS TO MAINLY NORTHERN NEVADA ON WEDNESDAY. DRY WEATHER THURSDAY THROUGH THE WEEKEND. && .UPDATE...SHORT WAVE TROUGH MOVING INTO UTAH AT THIS TIME WITH DECREASING SHOWERS ACROSS THE FORECAST AREA. UPDATED FORECASTS TO DECREASE SHOWERS COVERAGE TO SCATTERED ACROSS EASTERN NEVADA AND ISOLATED OVER THE WESTERN PORTION OF THE FORECAST AREA FOR THE REST OF THE DAY. ONLY ISOLATED SHOWERS NEAR THE UTAH BORDER THIS EVENING. 91 && .PREV DISCUSSION... /ISSUED AT 242 AM / SYNOPSIS...A LARGE SCALE TROUGH IS FORECAST THE NEXT COUPLE OF DAYS OVER THE GREAT BASIN. THIS FEATURE WILL HAVE EMBEDDED SHORTWAVES ROTATING AROUND THE BASE OF THE TROUGH. THIS PATTERN WILL BE CONDUCIVE TO WET SHOWERY WEATHER WITH ISOLATED THUNDERSTORMS FOR NORTHERN AND CENTRAL NEVADA TODAY AND TOMORROW. AS THE FRONTAL BOUNDARY MOVES THROUGH...PERIODS OF MODERATE TO LOCALLY HEAVY PRECIPITATION WILL BE POSSIBLE. ALSO EXPECTING GUSTY WINDS TODAY ALONG WITH BELOW NORMAL TEMPERATURES FOR LATE MAY. THE RIDGE WILL BUILD BACK INTO THE WEST ON FRIDAY AND SATURDAY. SHORT TERM...TODAY THROUGH WEDNESDAY. UNSETTLED WEATHER WILL BE ON TAP THIS FORECAST PERIOD AS A PACIFIC CYCLONE PUMMELS INTO THE SILVER STATE. THE GFS...ECMWF AND NAM CONTINUE TO HONE IN ON DIFFLUENT ONSHORE FLOW...ENHANCED PWS...AND A POTENT SHORTWAVE BISECTING THE REGION. THE INTEGRATED WATER VAPOR TRANSPORT VECTORS FROM THE GFS SUGGEST THAT THE LIONS SHARE OF THE MOISTURE WITH THIS SYSTEM REMAINS WEST OF THE SIERRA. HOWEVER...CONTINUE TO EXPECT QPF TO SPILL OVER INTO THE LKN CWA...WITH THE HRRR AND THE NAM12 PINGING INTO .25 OF AN INCH LIQUID QPF OR MORE WITH THIS EVENT. THE LOWEST SNOW LEVELS WILL BE OVER THE SHELDON NATIONAL WILDLIFE REFUGE...HOVERING BETWEEN 7100 AND 7300 FEET...AND CLOSER TO 8000 FEET FOR THE WESTERN ZONES. THE HRRR IMPLIES UPWARD VERTICAL VELOCITIES THAT WOULD SUPPORT TSRA...WHICH IS SUPPORTED BY THE +200 J/KG AND NEGATIVE LIS ON THE NAM12. HOWEVER...KEEP TS ACTIVITY ISOLATED IN THE GRIDS. IN ADDITION TO THE PRECIPITATION...EXPECTING GUSTY WINDS TODAY. GIVEN THE PRESSURE GRADIENT FORCES AT 700M AND 500MB...EXPECTED THE STRONGEST WINDS TO MATERIALIZE OVER NORTHERN NYE AND WHITE PINE COUNTIES. ISSUED A NPW FROM 21Z TO 03Z TODAY. EXPECTING A BREAK IN PRECIPITATION BEFORE A SECOND REINFORCING SHORTWAVE MOVES INTO NORTHERN NV RESULTING IN ADDITIONAL RAIN SHOWERS ON WEDNESDAY. BELOW NORMAL TEMPERATURES EXPECTED THIS FORECAST PERIOD. LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. ALL MODELS DEPICT A SHORTWAVE MOVING THROUGH THE FLOW WEDNESDAY NIGHT AND THURSDAY. THIS APPEARS TO BE A FAST MOVING SYSTEM AND IS EXPECTED TO BE WINDING DOWN SOMETIME EARLY THURSDAY MORNING FROM WEST TO EAST. THE FLOW REMAINS NORTHWESTERLY AS AN UPPER RIDGE TRIES TO WORK EAST. HIGHS ON THURSDAY WILL GENERALLY BE AROUND NORMAL FOR THIS TIME OF YEAR. BREEZY TO MAYBE WINDY CONDITIONS POSSIBLE THURSDAY AFTERNOON BUT AS IT STANDS RIGHT NOW...SHOULD BE BELOW ADVISORY THRESHOLDS. BY FRIDAY...RIDGING SHOULD CONTINUE TO BUILD OVER THE GREAT BASIN WITH THE AXIS SITUATED JUST TO THE WEST...ACROSS OREGON AND CALIFORNIA. HEIGHTS WILL CONTINUE TO RISE...SO SHOULD SEE SOME WARMING AS WELL DURING THE DAY...WITH AFTERNOON HIGHS ABOVE NORMAL. BY THE WEEKEND...MODELS DIVERGE ON THE POSITION AND STRENGTH OF A MIDWESTERN CANADIAN SYSTEM. SHOULD KEEP DRY WITH TEMPERATURES AT OR ABOVE NORMAL. AVIATION...SCT/NMRS -SHRA ACROSS THE AREA THIS MORNING WITH MVFR CONDITIONS POSSIBLE. BY 18Z LATER THIS MORNING...VCTS POSSIBLE AT KWMC...KELY...AND KEKO...CONTINUING IN THE AFTERNOON WITH MVFR/IFR CIGS/VSBY AT TIMES. SHRA WILL TAPER TO -SHRA FROM WEST TO EAST LATER THIS AFTERNOON AND EVENING. WINDS AT THE THREE TAF LOCATIONS W-NW10-20G30KT...SLIGHTLY STRONGER IN KELY. KTPH SHOULD REMAIN VFR...BUT WILL HAVE NW15-25G40KT...WITH POSSIBLE BLDU IN THE AFTERNOON. FIRE WEATHER...WETTING RAINS ARE POSSIBLE TODAY ACROSS ALL ZONES. AS THE FRONTAL BOUNDARY MOVES THROUGH...PERIODS OF MODERATE TO LOCALLY HEAVY PRECIPITATION WILL BE POSSIBLE...WITH ISOLATED TSRA. A SECOND SLUG OF PACIFIC ENERGY WILL FOLLOW IN ITS WAKE RESULTING IN MORE RAIN SHOWERS ON WEDNESDAY. MOST OF THE QPF WILL BE IN THE NORTHERN ZONES...WHERE THE MOISTURE AXIS IS LOCATED. EXPECTING BELOW NORMAL TEMPERATURES WITH NEGATIVE HEIGHT ANOMALIES THROUGH WEDNESDAY. THE RIDGE WILL BUILD INTO THE WEST ON FRIDAY AND SATURDAY...USHERING IN WARMER AND DRIER CONDITIONS. && .LKN WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS EVENING FOR NORTHEASTERN NYE COUNTY...NORTHWESTERN NYE COUNTY...WHITE PINE COUNTY. && $$ 97/92/97
AREA FORECAST DISCUSSION
NWS ELKO NV
242 AM PDT TUE MAY 28 2013 .SYNOPSIS...A LARGE SCALE TROUGH IS FORECAST THE NEXT COUPLE OF DAYS OVER THE GREAT BASIN. THIS FEATURE WILL HAVE EMBEDDED SHORTWAVES ROTATING AROUND THE BASE OF THE TROUGH. THIS PATTERN WILL BE CONDUCIVE TO WET SHOWERY WEATHER WITH ISOLATED THUNDERSTORMS FOR NORTHERN AND CENTRAL NEVADA TODAY AND TOMORROW. AS THE FRONTAL BOUNDARY MOVES THROUGH...PERIODS OF MODERATE TO LOCALLY HEAVY PRECIPITATION WILL BE POSSIBLE. ALSO EXPECTING GUSTY WINDS TODAY ALONG WITH BELOW NORMAL TEMPERATURES FOR LATE MAY. THE RIDGE WILL BUILD BACK INTO THE WEST ON FRIDAY AND SATURDAY. && .SHORT TERM...TODAY THROUGH WEDNESDAY. UNSETTLED WEATHER WILL BE ON TAP THIS FORECAST PERIOD AS A PACIFIC CYCLONE PUMMELS INTO THE SILVER STATE. THE GFS...ECMWF AND NAM CONTINUE TO HONE IN ON DIFFLUENT ONSHORE FLOW...ENHANCED PWS...AND A POTENT SHORTWAVE BISECTING THE REGION. THE INTEGRATED WATER VAPOR TRANSPORT VECTORS FROM THE GFS SUGGEST THAT THE LIONS SHARE OF THE MOISTURE WITH THIS SYSTEM REMAINS WEST OF THE SIERRA. HOWEVER...CONTINUE TO EXPECT QPF TO SPILL OVER INTO THE LKN CWA...WITH THE HRRR AND THE NAM12 PINGING INTO .25 OF AN INCH LIQUID QPF OR MORE WITH THIS EVENT. THE LOWEST SNOW LEVELS WILL BE OVER THE SHELDON NATIONAL WILDLIFE REFUGE...HOVERING BETWEEN 7100 AND 7300 FEET...AND CLOSER TO 8000 FEET FOR THE WESTERN ZONES. THE HRRR IMPLIES UPWARD VERTICAL VELOCITIES THAT WOULD SUPPORT TSRA...WHICH IS SUPPORTED BY THE +200 J/KG AND NEGATIVE LIS ON THE NAM12. HOWEVER...KEEP TS ACTIVITY ISOLATED IN THE GRIDS. IN ADDITION TO THE PRECIPITATION...EXPECTING GUSTY WINDS TODAY. GIVEN THE PRESSURE GRADIENT FORCES AT 700M AND 500MB...EXPECTED THE STRONGEST WINDS TO MATERIALIZE OVER NORTHERN NYE AND WHITE PINE COUNTIES. ISSUED A NPW FROM 21Z TO 03Z TODAY. EXPECTING A BREAK IN PRECIPITATION BEFORE A SECOND REINFORCING SHORTWAVE MOVES INTO NORTHERN NV RESULTING IN ADDITIONAL RAIN SHOWERS ON WEDNESDAY. BELOW NORMAL TEMPERATURES EXPECTED THIS FORECAST PERIOD. .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. ALL MODELS DEPICT A SHORTWAVE MOVING THROUGH THE FLOW WEDNESDAY NIGHT AND THURSDAY. THIS APPEARS TO BE A FAST MOVING SYSTEM AND IS EXPECTED TO BE WINDING DOWN SOMETIME EARLY THURSDAY MORNING FROM WEST TO EAST. THE FLOW REMAINS NORTHWESTERLY AS AN UPPER RIDGE TRIES TO WORK EAST. HIGHS ON THURSDAY WILL GENERALLY BE AROUND NORMAL FOR THIS TIME OF YEAR. BREEZY TO MAYBE WINDY CONDITIONS POSSIBLE THURSDAY AFTERNOON BUT AS IT STANDS RIGHT NOW...SHOULD BE BELOW ADVISORY THRESHOLDS. BY FRIDAY...RIDGING SHOULD CONTINUE TO BUILD OVER THE GREAT BASIN WITH THE AXIS SITUATED JUST TO THE WEST...ACROSS OREGON AND CALIFORNIA. HEIGHTS WILL CONTINUE TO RISE...SO SHOULD SEE SOME WARMING AS WELL DURING THE DAY...WITH AFTERNOON HIGHS ABOVE NORMAL. BY THE WEEKEND...MODELS DIVERGE ON THE POSITION AND STRENGTH OF A MIDWESTERN CANADIAN SYSTEM. SHOULD KEEP DRY WITH TEMPERATURES AT OR ABOVE NORMAL. && .AVIATION...SCT/NMRS -SHRA ACROSS THE AREA THIS MORNING WITH MVFR CONDITIONS POSSIBLE. BY 18Z LATER THIS MORNING...VCTS POSSIBLE AT KWMC...KELY...AND KEKO...CONTINUING IN THE AFTERNOON WITH MVFR/IFR CIGS/VSBY AT TIMES. SHRA WILL TAPER TO -SHRA FROM WEST TO EAST LATER THIS AFTERNOON AND EVENING. WINDS AT THE THREE TAF LOCATIONS W-NW10-20G30KT...SLIGHTLY STRONGER IN KELY. KTPH SHOULD REMAIN VFR...BUT WILL HAVE NW15-25G40KT...WITH POSSIBLE BLDU IN THE AFTERNOON. && .FIRE WEATHER...WETTING RAINS ARE POSSIBLE TODAY ACROSS ALL ZONES. AS THE FRONTAL BOUNDARY MOVES THROUGH...PERIODS OF MODERATE TO LOCALLY HEAVY PRECIPITATION WILL BE POSSIBLE...WITH ISOLATED TSRA. A SECOND SLUG OF PACIFIC ENERGY WILL FOLLOW IN ITS WAKE RESULTING IN MORE RAIN SHOWERS ON WEDNESDAY. MOST OF THE QPF WILL BE IN THE NORTHERN ZONES...WHERE THE MOISTURE AXIS IS LOCATED. EXPECTING BELOW NORMAL TEMPERATURES WITH NEGATIVE HEIGHT ANOMALIES THROUGH WEDNESDAY. THE RIDGE WILL BUILD INTO THE WEST ON FRIDAY AND SATURDAY...USHERING IN WARMER AND DRIER CONDITIONS. && .LKN WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS EVENING FOR NORTHEASTERN NYE COUNTY...NORTHWESTERN NYE COUNTY...WHITE PINE COUNTY. && $$ 97/92/92/97
AREA FORECAST DISCUSSION
NWS BUFFALO NY
947 PM EDT WED MAY 29 2013 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH OF THE REGION...ALLOWING A HOT AND HUMID AIRMASS TO BUILD ACROSS THE REGION FOR THE REMAINDER OF THE WEEK. WEATHER WILL BECOME MORE UNSETTLED AS A COLD FRONT APPROACHES FROM THE UPPER LAKES SATURDAY...AND MOVES ACROSS THE REGION ON SUNDAY. && .NEAR TERM /THROUGH THURSDAY/... AT 945 PM...RADAR SHOWED DRY WEATHER ACROSS WESTERN NEW YORK. THE REMNANTS OF CONVECTION UPSTREAM CAN STILL BE SEEN ON IR SATELLITE IMAGERY. SOME GUIDANCE HINTS AT THIS...INCLUDING THE 18Z NAM AND SEVERAL HRRR RUNS. GIVEN UPSTREAM RADAR...DO NOT EXPECT WIDESPREAD COVERAGE...BUT CANNOT RULE OUT A SHOWER OR POSSIBLY A THUNDERSTORM AS THIS MOVES ACROSS DURING THE EARLY MORNING HOURS. TEMPS TONIGHT WILL BE QUITE MILD WITH A GOOD MIXING BREEZE HOLDING OVERNIGHT LOWS IN THE LOWER 60S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND TUG HILL...AND THE MID 60S ELSEWHERE. ANY CONVECTION SHOULD COME TO AN END LATE OVERNIGHT...AND A STRENGTHENING UPPER RIDGE COMBINED WITH THE WESTWARD NUDGE OF THE BERMUDA HIGH WILL BOOST TEMPS ON THURSDAY TO THE LOWER TO MID 80S ACROSS THE NORTH COUNTRY AND THE MID TO UPPER 80S ELSEWHERE...EVEN TO THE LOW 90S CLOSER TO THE FINGER LAKES AND GENESEE VALLEY. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS ADVERTISED FOR THE PAST SEVERAL DAYS...VERY WARM AND MODERATELY HUMID CONDITIONS WILL CONTINUE DURING THIS PERIOD. A MID SUMMER `BERMUDA HIGH` WILL KEEP A FLOW OF 16 TO 18C H85 AIR FLOWING NORTHWARDS ACROSS OUR FORECAST AREA...AND THIS WILL SUPPORT AFTERNOON TEMPERATURES OF 85 TO 90 WITH SULTRY OVERNIGHT LOWS IN THE MID TO UPPER 60S. THESE READINGS WILL BE MORE TYPICAL OF MID JULY. ONE USUALLY CANNOT HAVE SULTRY CONDITIONS WITHOUT HAVING AT LEAST THE THREAT FOR CONVECTION...AND THAT WILL BE THE CASE AS WE ADVANCE THROUGH THE END OF THE WEEK. WHILE THE VAST MAJORITY OF THE TIME WILL BE RAIN-FREE...THERE WILL BE THE RISK FOR THUNDERSTORMS THAT WILL BE FOCUSED MAINLY NEAR LAKE BREEZE BOUNDARIES. DIGGING INTO THE DETAILS... THE CREST OF A H5 RIDGE ARCHING BACK ACROSS EASTERN ONTARIO AND THE LOWER GREAT LAKES FROM THE MID ATLANTIC COAST WILL PROVIDE US WITH A WARM AND DRY THURSDAY NIGHT. ENERGY EJECTING OUT OF A CLOSED LOW OVER THE NORTHERN PLAINS WILL START TO FLATTEN THIS RIDGE AXIS ON FRIDAY THOUGH...AND THIS MAY BE JUST ENOUGH TO HELP WEAKEN A SUBSIDENCE INVERSION THAT WAS A SIGNIFICANT INHIBITOR TO CONVECTION FROM THE DAY BEFORE. SBCAPES OF 1500 J/KG ARE EXPECTED ACROSS THE SRN TIER FRIDAY AFTERNOON...AND WITH A WEAKENED CAP AND A LAKE BREEZE BOUNDARY FORECAST TO BE MOVING EAST...THERE WILL BE THE CHANCE FOR SOME THUNDERSTORMS FOR SITES GENERALLY EAST OF A LINE FROM BATAVIA TO JAMESTOWN. WHILE THE WIND FIELDS DO NOT SUPPORT A SOLID THREAT FOR SEVERE WEATHER...ANY STORMS THAT DEVELOP NEAR THE LAKE BREEZE BOUNDARY COULD BECOME ROBUST ENOUGH TO PRODUCE LOCALLY GUSTY WINDS AND SMALL HAIL. OTHERWISE...THE BULK OF THE REGION WILL BE RAIN FREE ON FRIDAY WITH AFTERNOON TEMPERATURES CLOSE TO 90 AWAY FROM THE LAKES. DIURNALLY INDUCED CONVECTION WILL DIE OFF FRIDAY EVENING...BUT WILL KEEP SLGT CHC POPS IN PLACE OVERNIGHT TO COVER THE UNLIKELY CHANCE FOR ACTIVITY THAT ACCOMPANIES ANY SHORTWAVES THAT LIFT ACROSS THE FLATTENING H5 RIDGE. LIKE THE PREVIOUS NIGHT...IT WILL BE A WARM AND MUGGY NIGHT ACROSS THE REGION WITH LOWS GENERALLY IN THE MID TO UPPER 60S. SATURDAY HAS THE POTENTIAL TO BE MORE UNSETTLED THAN FRIDAY. WE WILL STILL HAVE A WARM UNSTABLE AIRMASS IN PLACE...BUT WE WILL ALSO FIND OURSELVES WITHIN THE JET ENTRANCE REGION OF A 120KT H25 JET THAT WILL BE STREAMING ACROSS ONTARIO AND THE UPPER GREAT LAKES. THE ADDED SYNOPTIC LIFT TO AN INCREASINGLY BUOYANT AIRMASS COULD LEAD TO MORE WIDESPREAD AFTERNOON CONVECTION. WHILE PORTIONS OF THE IAG FRONTIER SHOULD ONCE AGAIN BE `SHADOWED` BY LAKE ERIE...WILL INCREASE LOW CHC POPS FROM CONTINUITY BY ABOUT 10 POINTS OVER THE REMAINDER OF THE FORECAST AREA. IT WILL ONCE AGAIN BE QUITE WARM...BUT WE SHOULD HAVE A LITTLE MORE CLOUD COVER SO WILL MAX TEMPS SHOULD BE A DEGREE OR TWO LOWER THAN THE PREVIOUS DAY. A LONGWAVE TROUGH WILL EASE ACROSS THE UPPER GREAT LAKES SATURDAY NIGHT WHILE A COMPLEX AREA OF LOW PRESSURE AND ASSOCIATED FRONTAL SYSTEM WILL CROSS LOWER MICHIGAN AND SOUTHERN ONTARIO. THIS SHOULD LEAD TO THE LIKELIHOOD OF SHOWERS AND THUNDERSTORMS OVERNIGHT... ESPECIALLY OVER THE WESTERN COUNTIES. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... IT WILL CERTAINLY BE COOLER...AND TO MANY...MORE COMFORTABLE EARLY NEXT WEEK. A SPLIT FLOW OVER NORTH AMERICA WILL INCLUDE A LONG WAVE TROUGH OVER EASTERN CANADA...AND THIS ALLOW H85 TEMPS TO DROP OFF INTO THE SINGLE DIGITS. BEFORE WE GET TO THAT POINT THOUGH...WE WILL HAVE SOME VERY UNSETTLED CONDITIONS TO CONTEND WITH ON SUNDAY. A WAVY FRONTAL SYSTEM WILL SINK ACROSS THE FORECAST AREA ON SUNDAY AND THIS WILL PRODUCE FAIRLY WIDESPREAD SHOWERS AND THUNDERSTORMS. GIVEN THE SLOW MOVEMENT OF THE FRONT AND PWAT VALUES IN EXCESS OF 1.5 INCHES...THERE WILL BE A HEIGHTENED RISK FOR SIGNIFICANT RAINS. STUBBORN CLEARING IS EXPECTED IN THE WAKE OF THE FRONT SUNDAY NIGHT...BUT AT LEAST IT WILL BE MORE TOLERABLE FOR SLEEPING WITH MIN TEMPS FORECAST TO BE IN THE 50S. THE BASE OF A DIGGING H5 TROUGH WILL SWING ACROSS TO THE NORTH OF LK ONTARIO ON MONDAY...AND WHILE THE MAJORITY OF THE DAY WILL BE RAIN FREE...WILL KEEP SLGT TO LOW CHC POPS FOR ANY NUISANCE SHOWER ACTIVITY. THE HIGHEST CHANCE FOR SHRA`S WILL BE FOUND IN THE AFTERNOON ACROSS THE NORTH COUNTRY. HIGH TEMPERATURES WILL ONLY BE IN THE 60S. EXPANSIVE CANADIAN HIGH PRESSURE SHOULD THEN PROVIDE OUR REGION WITH BEAUTIFUL WEATHER TUESDAY AND WEDNESDAY...AS BOUNTIFUL SUNSHINE WILL BE ACCOMPANIED BY HIGH TEMPERATURES IN THE LOWER 70S. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... EXPECT MAINLY VFR CONDITIONS THROUGH THIS EVENING. A WEAK DISTURBANCE WILL PASS DURING THE EARLY MORNING HOURS...BRINGING A MINIMAL CHANCE FOR SHOWERS AND POSSIBLY A THUNDERSTORM. LATE OVERNIGHT THE IS A CHANCE OF MVFR VSBYS IN LIGHT FOG TIL JUST AFTER DAYBREAK...THEN VFR THROUGH THE DAY ON THURSDAY. OUTLOOK... THURSDAY NIGHT THROUGH SATURDAY...MAINLY VFR. SUNDAY...MVFR WITH RAIN SHOWERS. MONDAY...VFR. && .MARINE... SOUTHWEST WINDS WILL SLACKEN A BIT OVERNIGHT WITH FEWER GUSTS AND SPEEDS FALLING TO AROUND 10 KNOTS. UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL KEEP LIGHT WINDS ACROSS THE EASTERN LAKES FOR THE NEXT FEW DAYS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...WCH NEAR TERM...APFFEL/WCH SHORT TERM...RSH LONG TERM...RSH AVIATION...APFFEL/WCH MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
849 PM EDT WED MAY 29 2013 .SYNOPSIS... A WARM FRONT WILL PUSH NORTHEASTWARD ACROSS NORTH CENTRAL NEW YORK THIS EVENING WITH A SOME SHOWERS AND THUNDERSTORMS. A HOT AND HUMID AIRMASS WILL BUILD INTO THE REGION FOR THE REST OF THE WEEK. && .NEAR TERM /THROUGH THURSDAY/... SHOWERS AND THUNDERSTORMS HAVE EXITED THE REGION...WITH JUST A FEW SHOWERS LINGERING ACROSS THE SOUTHERN TIER AND PERHAPS THE SAINT LAWRENCE VALLEY AS WELL. EXPECT THIS DIMINISHING TREND TO CONTINUE THIS EVENING...WITH THE VAST MAJORITY OF THE CWA TO REMAIN DRY DURING THIS TIME. AFTER THIS...THE REMNANTS OF CONVECTION UPSTREAM CAN STILL BE SEEN ON IR SATELLITE IMAGERY. SOME GUIDANCE HINTS AT THIS...INCLUDING THE 18Z NAM AND SEVERAL HRRR RUNS. GIVEN UPSTREAM RADAR...DO NOT EXPECT WIDESPREAD COVERAGE...BUT CANNOT RULE OUT A SHOWER OR POSSIBLY A THUNDERSTORM AS THIS MOVES ACROSS DURING THE EARLY MORNING HOURS. TEMPS TONIGHT WILL BE QUITE MILD WITH A GOOD MIXING BREEZE HOLDING OVERNIGHT LOWS IN THE LOWER 60S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND TUG HILL...AND THE MID 60S ELSEWHERE. ANY CONVECTION SHOULD COME TO AN END LATE OVERNIGHT...AND A STRENGTHENING UPPER RIDGE COMBINED WITH THE WESTWARD NUDGE OF THE BERMUDA HIGH WILL BOOST TEMPS ON THURSDAY TO THE LOWER TO MID 80S ACROSS THE NORTH COUNTRY AND THE MID TO UPPER 80S ELSEWHERE...EVEN TO THE LOW 90S CLOSER TO THE FINGER LAKES AND GENESEE VALLEY. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS ADVERTISED FOR THE PAST SEVERAL DAYS...VERY WARM AND MODERATELY HUMID CONDITIONS WILL CONTINUE DURING THIS PERIOD. A MID SUMMER `BERMUDA HIGH` WILL KEEP A FLOW OF 16 TO 18C H85 AIR FLOWING NORTHWARDS ACROSS OUR FORECAST AREA...AND THIS WILL SUPPORT AFTERNOON TEMPERATURES OF 85 TO 90 WITH SULTRY OVERNIGHT LOWS IN THE MID TO UPPER 60S. THESE READINGS WILL BE MORE TYPICAL OF MID JULY. ONE USUALLY CANNOT HAVE SULTRY CONDITIONS WITHOUT HAVING AT LEAST THE THREAT FOR CONVECTION...AND THAT WILL BE THE CASE AS WE ADVANCE THROUGH THE END OF THE WEEK. WHILE THE VAST MAJORITY OF THE TIME WILL BE RAIN-FREE...THERE WILL BE THE RISK FOR THUNDERSTORMS THAT WILL BE FOCUSED MAINLY NEAR LAKE BREEZE BOUNDARIES. DIGGING INTO THE DETAILS... THE CREST OF A H5 RIDGE ARCHING BACK ACROSS EASTERN ONTARIO AND THE LOWER GREAT LAKES FROM THE MID ATLANTIC COAST WILL PROVIDE US WITH A WARM AND DRY THURSDAY NIGHT. ENERGY EJECTING OUT OF A CLOSED LOW OVER THE NORTHERN PLAINS WILL START TO FLATTEN THIS RIDGE AXIS ON FRIDAY THOUGH...AND THIS MAY BE JUST ENOUGH TO HELP WEAKEN A SUBSIDENCE INVERSION THAT WAS A SIGNIFICANT INHIBITOR TO CONVECTION FROM THE DAY BEFORE. SBCAPES OF 1500 J/KG ARE EXPECTED ACROSS THE SRN TIER FRIDAY AFTERNOON...AND WITH A WEAKENED CAP AND A LAKE BREEZE BOUNDARY FORECAST TO BE MOVING EAST...THERE WILL BE THE CHANCE FOR SOME THUNDERSTORMS FOR SITES GENERALLY EAST OF A LINE FROM BATAVIA TO JAMESTOWN. WHILE THE WIND FIELDS DO NOT SUPPORT A SOLID THREAT FOR SEVERE WEATHER...ANY STORMS THAT DEVELOP NEAR THE LAKE BREEZE BOUNDARY COULD BECOME ROBUST ENOUGH TO PRODUCE LOCALLY GUSTY WINDS AND SMALL HAIL. OTHERWISE...THE BULK OF THE REGION WILL BE RAIN FREE ON FRIDAY WITH AFTERNOON TEMPERATURES CLOSE TO 90 AWAY FROM THE LAKES. DIURNALLY INDUCED CONVECTION WILL DIE OFF FRIDAY EVENING...BUT WILL KEEP SLGT CHC POPS IN PLACE OVERNIGHT TO COVER THE UNLIKELY CHANCE FOR ACTIVITY THAT ACCOMPANIES ANY SHORTWAVES THAT LIFT ACROSS THE FLATTENING H5 RIDGE. LIKE THE PREVIOUS NIGHT...IT WILL BE A WARM AND MUGGY NIGHT ACROSS THE REGION WITH LOWS GENERALLY IN THE MID TO UPPER 60S. SATURDAY HAS THE POTENTIAL TO BE MORE UNSETTLED THAN FRIDAY. WE WILL STILL HAVE A WARM UNSTABLE AIRMASS IN PLACE...BUT WE WILL ALSO FIND OURSELVES WITHIN THE JET ENTRANCE REGION OF A 120KT H25 JET THAT WILL BE STREAMING ACROSS ONTARIO AND THE UPPER GREAT LAKES. THE ADDED SYNOPTIC LIFT TO AN INCREASINGLY BUOYANT AIRMASS COULD LEAD TO MORE WIDESPREAD AFTERNOON CONVECTION. WHILE PORTIONS OF THE IAG FRONTIER SHOULD ONCE AGAIN BE `SHADOWED` BY LAKE ERIE...WILL INCREASE LOW CHC POPS FROM CONTINUITY BY ABOUT 10 POINTS OVER THE REMAINDER OF THE FORECAST AREA. IT WILL ONCE AGAIN BE QUITE WARM...BUT WE SHOULD HAVE A LITTLE MORE CLOUD COVER SO WILL MAX TEMPS SHOULD BE A DEGREE OR TWO LOWER THAN THE PREVIOUS DAY. A LONGWAVE TROUGH WILL EASE ACROSS THE UPPER GREAT LAKES SATURDAY NIGHT WHILE A COMPLEX AREA OF LOW PRESSURE AND ASSOCIATED FRONTAL SYSTEM WILL CROSS LOWER MICHIGAN AND SOUTHERN ONTARIO. THIS SHOULD LEAD TO THE LIKELIHOOD OF SHOWERS AND THUNDERSTORMS OVERNIGHT... ESPECIALLY OVER THE WESTERN COUNTIES. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... IT WILL CERTAINLY BE COOLER...AND TO MANY...MORE COMFORTABLE EARLY NEXT WEEK. A SPLIT FLOW OVER NORTH AMERICA WILL INCLUDE A LONG WAVE TROUGH OVER EASTERN CANADA...AND THIS ALLOW H85 TEMPS TO DROP OFF INTO THE SINGLE DIGITS. BEFORE WE GET TO THAT POINT THOUGH...WE WILL HAVE SOME VERY UNSETTLED CONDITIONS TO CONTEND WITH ON SUNDAY. A WAVY FRONTAL SYSTEM WILL SINK ACROSS THE FORECAST AREA ON SUNDAY AND THIS WILL PRODUCE FAIRLY WIDESPREAD SHOWERS AND THUNDERSTORMS. GIVEN THE SLOW MOVEMENT OF THE FRONT AND PWAT VALUES IN EXCESS OF 1.5 INCHES...THERE WILL BE A HEIGHTENED RISK FOR SIGNIFICANT RAINS. STUBBORN CLEARING IS EXPECTED IN THE WAKE OF THE FRONT SUNDAY NIGHT...BUT AT LEAST IT WILL BE MORE TOLERABLE FOR SLEEPING WITH MIN TEMPS FORECAST TO BE IN THE 50S. THE BASE OF A DIGGING H5 TROUGH WILL SWING ACROSS TO THE NORTH OF LK ONTARIO ON MONDAY...AND WHILE THE MAJORITY OF THE DAY WILL BE RAIN FREE...WILL KEEP SLGT TO LOW CHC POPS FOR ANY NUISANCE SHOWER ACTIVITY. THE HIGHEST CHANCE FOR SHRA`S WILL BE FOUND IN THE AFTERNOON ACROSS THE NORTH COUNTRY. HIGH TEMPERATURES WILL ONLY BE IN THE 60S. EXPANSIVE CANADIAN HIGH PRESSURE SHOULD THEN PROVIDE OUR REGION WITH BEAUTIFUL WEATHER TUESDAY AND WEDNESDAY...AS BOUNTIFUL SUNSHINE WILL BE ACCOMPANIED BY HIGH TEMPERATURES IN THE LOWER 70S. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... EXPECT MAINLY VFR CONDITIONS THROUGH THIS EVENING. A WEAK DISTURBANCE WILL PASS DURING THE EARLY MORNING HOURS...BRINGING A MINIMAL CHANCE FOR SHOWERS AND POSSIBLY A THUNDERSTORM. LATE OVERNIGHT THE IS A CHANCE OF MVFR VSBYS IN LIGHT FOG TIL JUST AFTER DAYBREAK...THEN VFR THROUGH THE DAY ON THURSDAY. OUTLOOK... THURSDAY NIGHT THROUGH SATURDAY...MAINLY VFR. SUNDAY...MVFR WITH RAIN SHOWERS. MONDAY...VFR. && .MARINE... SOUTHWEST WINDS WILL SLACKEN A BIT OVERNIGHT WITH FEWER GUSTS AND SPEEDS FALLING TO AROUND 10 KNOTS. UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL KEEP LIGHT WINDS ACROSS THE EASTERN LAKES FOR THE NEXT FEW DAYS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...WCH NEAR TERM...APFFEL/WCH SHORT TERM...RSH LONG TERM...RSH AVIATION...APFFEL/WCH MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
338 PM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL MOVE THROUGH THE AREA OVERNIGHT BRINGING WITH IT A ROUND OF SHOWERS AND THUNDERSTORMS. BEHIND THE FRONT A LINGERING CHANCE OF THUNDERSTORMS WILL EXIST WEDNESDAY AFTERNOON...SOME OF WHICH COULD CONTAIN GUSTY WINDS. WE WILL EXPERIENCE DRIER WEATHER THURSDAY AND FRIDAY BUT IT WILL BE HOT WITH TEMPERATURES WELL INTO THE 80S TO NEAR 90. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 330 PM UPDATE... THE STEADIEST OF THE RAIN IS MOVING TO OUR EAST NOW. WILL MAINTAIN LOW CHANCE TO SLIGHT CHANCE POPS THROUGH THE EVENING HOWEVER BECAUSE WHILE MOST WILL SEE A LULL IN PRECIPITATION...ENOUGH SCT. SHOWERS EXISTS AROUND TO WARRANT THESE POPS. MAIN ATTENTION HOWEVER IS TO A LINE OF SHOWERS AND THUNDERSTORMS NOW NEAR DETROIT. AS THE HRRR FIRST HINTED AT THIS MORNING...THE HIGHER RESOLUTION MODELS SUCH AS THE ARW AND NMM ARE NOW FOLLOWING CLOSELY BRINGING THIS AREA OF SHOWERS AND THUNDERSTORMS ACROSS LAKE ERIE AND INTO OUR AREA. AT FIRST IT APPEARED THE MODELS MAY BE TOO FAR NORTH WITH THIS FEATURE WITH THE BEST INSTABILITY VALUES TO OUR SOUTHWEST OVER WESTERN PA. HOWEVER BASED ON WHAT IS HAPPENING NOW...IT APPEARS THE CONVECTION WILL RIDE ALONG THE NORTHERN GRADIENT OF THE INSTABILITY...WHICH WILL FAVOR THE FINGER LAKES AND CENTRAL NEW YORK BETWEEN 03Z AND 07Z. THE SOUTHERN EDGE OF THE PRECIP SHOULD BE THE SOUTHERN TIER OF NY...WITH NOT AS MUCH HAPPENING FARTHER SOUTH TOWARD KAVP. THUNDER IS LIKELY WITH THIS AREA OF RAIN AS IT MOVES EAST. WHILE SURFACE BASED CAPES ARE EITHER 0 OR JUST A FEW HUNDRED J/KG...WE ARE SEEING LIGHTNING NOW NEAR DETROIT WITH THE SAME VALUES. IN ADDITION SHOWALTER VALUES GO NEGATIVE OVERNIGHT. ALL AND ALL LOOKING AT A 2 TO 4 HOUR PERIOD OF HEAVIER RAIN WITH THUNDER A GOOD BET. AS THE WARM FRONT LIFTS THROUGH OUR AREA CHANCES FOR POPS WILL DECREASE TOWARD DAYBREAK WHILE LIFTING NORTHEAST TOWARD THE MOHAWK VALLY. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/... 330 PM UPDATE... THE AREA REMAINS IN A SLIGHT RISK FOR SEVERE WEATHER WEDNESDAY AND IT HAS BEEN EXPANDED A BIT FARTHER SOUTH THAN THE EARLY MORNING UPDATE FROM SPC. IT STILL APPEARS THE BEST THREAT FOR STORMS WILL BE DURING THE AFTERNOON AND FROM THE NORTHERN TIER COUNTIES OF PA NORTH THROUGH CNY WHICH WILL BE CLOSER TO THE BEST UPPER LEVEL LIFT. MOST IF NOT ALL OF THE AREA SHOULD BE IN THE WARM SECTOR WITH THE WARM FRONT EITHER ACROSS OUR FAR NORTHEAST IF NOT OVER NNY. THIS COMBINED WITH A SHORT WAVE MOVING CLOSE BUT JUST TO OUR NORTH AND 0-6 KM BULK SHEAR VALUES OF 30 KTS GIVE US THE POTENTIAL FOR DAMAGING WINDS AND HAIL. HIGHER RESOLUTION MODELS AT THIS EARLY STAGE POINT TOWARD A LINEAR SQUALL LINE MOVING THROUGH BETWEEN 18Z AND 0Z. WILL CONTINUE WITH HIGH CHANCE TO LIKELY POPS AND CONTINUE TO MENTION GUSTY WINDS IN THE FORECAST AND HWO. AFTER THE CONVECTION DIES DOWN WEDNESDAY EVENING...THE MAIN STORY WILL BE THE HEAT BUILDING INTO OUR AREA. WHILE BOTH THE NAM AND GFS SUGGEST LOW CHANCE POPS LATE THURSDAY AFTERNOON ACROSS THE NORTH AND FRIDAY AFTERNOON OVER WESTERN NY...A DEVELOPING CAP AROUND 10KT SHOULD KEEP OUR IMPRESSIVE CAPE VALUES FROM BEING A PROBLEM. 850 TEMPS BETWEEN 15C TO 18C SUPPORT HIGHS WELL INTO THE 80S BOTH DAYS...WITH NEAR 90 OR LOWER 90S LIKELY ESPECIALLY BY FRIDAY IN THE LOWER ELEVATIONS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... 220 PM UPDATE... VRY FEW CHGS NEEDED TO LONG TERM FCST THIS AFTN. ONLY TWEAK WAS TO INCRS POPS AS IT LOOKS TO BE FAIRLY REASONABLE THAT ALL MODELS, INCLUDING ENSEMBLES, SHOWING FROPA OCCURRING ARND 12Z MONDAY. THUS, HV BOOSTED POPS TO LKLY SUN NGT FOR STARTERS THO THESE MAY NEED TO BE TWEAKED WITH LATER FCSTS. MED RANGE GUIDANCE ALSO HINTING THAT TROFFING WL BE MVG TWD THE WRN LAKES ON SUN NGT. WITH THIS FEATURE MVG CLOSER TO CWA, CLDS WL OVRSPRD THE REGION DRG THE DAY SUNDAY WITH SLGTLY COOLER TEMPS EXPECTED, THO STILL ABV NORMAL. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... 18Z UPDATE... IFR CONDITIONS AT KELM AND KBGM TERMINALS THIS AFTERNOON WITH SIGNIFICANT MOISTURE TRAPPED UNDER LOW-LEVEL INVERSION. AREA OF LIGHT TO MODERATE RAIN MOVING THROUGH WITH MVFR-IFR RESTRICTIONS. ONCE THIS RAIN MOVES THROUGH, A BREAK IS EXPECTED WITH POTENTIAL RETURN TO MVFR BEFORE NEXT SYSTEM ROLLS THROUGH AFTER 04Z. STILL A LITTLE UNCERTAINTY AS TO HOW MUCH RAIN WILL AFFECT KITH/KELM/KBGM AND KAVP, THUS HAVE LEFT PCPN MENTION OUT OF THESE TERMINALS AT THIS TIME. FURTHER NORTH AT KSYR AND KRME HAVE INCLUDED SHOWER MENTION THROUGH THE END OF THE TAF PERIOD WITH POSSIBLE -TSRA BETWEEN 03Z AND 07Z. WINDS AROUND 10KTS OUT OF THE ESE WITH GRADUALLY SHIFT AROUND TO THE SOUTHWEST BY 12Z BETWEEN 10-15KTS. OUTLOOK... WED...MVFR IN SCT SHRA/TSRA. THU-SAT...MAINLY VFR. SUN...POTENTIAL FOR MVFR IN SHRA/TSRA AS COLD FRONT APPROACHES. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...HEDEN NEAR TERM...HEDEN SHORT TERM...HEDEN LONG TERM...PVN AVIATION...PVN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
232 PM EDT TUE MAY 28 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL BECOME WELL ESTABLISHED...BRINGING A RETURN TO SUMMERTIME HEAT INTO EARLY NEXT WEEK. SHOWERS AND THUNDERSTORMS MAY DEVELOP DURING THE HEAT OF THE DAY BY THE WEEKEND. A COLD FRONT WILL APPROACH FROM THE WEST LATE MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 230 PM TUESDAY...IMPRESSIVE WV IMAGERY THIS AFTN PAINTS THE PICTURE ACROSS THE SOUTHEAST. EXPANSIVE AREA OF CONVECTION DRAPED FROM NORTHERN MEXICO...INTO IOWA...AND EAST INTO NEW ENGLAND...BOUNDS THE WESTERN AND NORTHERN PERIPHERY OF AN UPPER RIDGE CONTROLLING THE SYNOPTIC REGIME OVER THE SOUTHEAST. WHILE CU HAS BEEN WIDESPREAD THIS AFTN...VERTICAL DEPTH OF THE CLOUDS IS QUITE LIMITED THANKS TO WEAK FORCING AND INCREASING CONVECTIVE LID BENEATH BUILDING THERMAL RIDGE ALOFT. HAVE KEPT POP JUST BELOW THRESHOLD FOR THE REST OF THE DAY. HRRR CONTINUING TO SUGGEST SOME ISOLATED SHOWERS TODAY...BUT IT CONTINUES TO BE OVER AGGRESSIVE IN DEVELOPING DEEP CONVECTION SO HAVE IGNORED IT AND LEANED ON ARW/NAM WHICH KEEP TODAY DRY. CONVECTIVE/DIURNAL CU WILL SLOWLY ERODE THIS AFTN/EVE...AND ALTHOUGH THERE MAY BE SOME HIGH LEVEL DEBRIS CLOUDINESS...OVERALL A MOSTLY CLEAR NIGHT IS EXPECTED. WITH DEWPOINTS SURGING THIS AFTN ON MOIST SE FLOW...CROSSOVER TEMPS WILL BE APPROACHED TONIGHT. ATTM DO NOT EXPECT THEM TO BE EXCEEDED HOWEVER...MINS FALLING ONLY INTO THE MID/UPR 60S...AND THIS COMBINED WITH 15 KTS OF WIND JUST ABOVE THE NOCTURNAL INVERSION WILL INHIBIT WIDESPREAD FOG. STILL...HAVE LEFT SOME PATCHY FOG IN THE WX GRIDS AFTER MIDNIGHT. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 230 PM TUESDAY...BUILDING RIDGE ALOFT AND THE ESTABLISHMENT OF THE BERMUDA HIGH WILL LEAD TO A BENIGN SHORT TERM PERIOD. TEMPS WILL PRIMARILY BE PERSISTENCE WITH HIGHS IN THE MID/UPPER 80S ACROSS THE PEE DEE/LBT AREAS AND LOWER 80S COASTAL SECTIONS (NEAR 80 BEACHES) EACH DAY. MEANWHILE EXPECT LIGHT ONSHORE FLOW TO TO SUPPORT LOWS IN THE LOWER TO MID 60S EACH NIGHT. COULD SEE PATCHY FLOG EACH MORNING...WITH POSSIBLY SOME STRATUS FOR A BRIEF PERIOD LATE THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 230 PM TUESDAY...FRIDAY APPEARS TO OFFER A CONVECTIVE MINIMUM THROUGH THE PERIOD. THE BERMUDA HIGH WILL BE PUMPING WARMTH AND MOISTURE ACROSS THE REGION BUT UPPER RIDGING MAY HAVE JUST ENOUGH AN INFLUENCE AT CAPPING ALL BUT ISO COVERAGE. NOT SEEING MUCH EVIDENCE OF PIEDMONT TROUGH SO IT MAY BE CONFINED TO THE SEA BREEZE. OVER THE WEEKEND THE UPPER RIDGE MOVES EASTWARD AND RELAXES ITS SUPPRESSING EFFECTS ON CONVECTION. COVERAGE MAY STILL BE ISOLATED IN THE ABSENCE OF ANYTHING BUT MESOSCALE FORCING AND SO THE SEA BREEZE SEEMS THE MOST LIKELY CULPRIT. SHOULD THE APPROACHING UPPER TROUGH BE QUICK ENOUGH IT MAY SPREAD SW INCREASING WINDS OVER MAINLY WRN ZONES TO ENHANCE POPS THERE BUT WITH THE ANTECEDENT RIDGE THINK IT/LL BE SLOWER. IN FACT THE EFFECTS OF THE DOWNSTREAM RIDGE CAN BE SEEN IN THE WAY GUIDANCE HANDLES THE APPROACH OF THE TROUGH...IT BECOMES GRADUALLY POSITIVELY TILTED WITH TIME. AS A RESULT INTO NEXT WEEK THE FRONT IT DRIVES DECELERATES. ITS PROXIMITY TO OUR NW COULD FUNNEL EXTRA MOISTURE INTO THE CAROLINAS FOR SOME SLIGHTLY HIGHER COVERAGE OF THUNDERSTORMS EACH AFTERNOON. TRUE TO A WARM SEASON PATTERN THERE ARE LITTLE DAY TO DAY VARIATIONS IN TEMPERATURES EITHER FROM ONE ANOTHER OR FROM CLIMO. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 18Z...BERMUDA HIGH WILL KEEP US IN SOUTHERLY FLOW THROUGH THE FORECAST PERIOD. LOOK FOR SCATTERED CU ALONG AND WEST OF THE SEA BREEZE RESULTANT THIS AFTERNOON. THE HRRR MODEL IS SHOWING SCATTERED SHOWERS...BUT FEEL THEY WILL BE ISOLATED AT BEST. SOUTH SOUTHEAST FLOW WILL DIMINISH THIS EVENING. SOME FOG IS POSSIBLE JUST BEFORE SUNRISE...BUT GIVEN THE WINDS AT THE BOUNDARY LAYER ARE AROUND 15 KTS...THINK ANY FOG WILL BE QUITE LIGHT. WEDNESDAY...CONTINUED VFR WITH MORE OF A SOUTHWEST COMPONENT. EXTENDED OUTLOOK...MORNING MVFR/ISOLATED IFR FOG THROUGH SUNDAY. ISOLATED SHOWERS SATURDAY AND SUNDAY...MAINLY WEST. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 230 PM TUESDAY...OFFSHORE HIGH PRESSURE TO CONTINUE TO DOMINATE THE SYNOPTIC ENVIRONMENT...CREATING RELATIVELY WEAK SE WINDS OVER THE WATERS. BUOYS TODAY HAVE SHOWN WINDS REMAINING BELOW 10 KTS...AND EXPECT THESE TO REMAIN ROUGHLY UNCHANGED THROUGH THE PERIOD. WITH THE LIGHT WINDS...WIND-WAVE CONTRIBUTION TO THE SPECTRUM IS LIMITED...SO A 2-3FT/9SEC SE SWELL WILL DOMINATE AND WAVES WILL REMAIN 2-3 FT THROUGH TONIGHT. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 230 PM TUESDAY...BERMUDA HIGH PRESSURE IN A STAGNANT PATTERN WILL KEEP THE FLOW OUT OF A SOUTHEAST TO SOUTH DIRECTION THROUGH THE SHORT TERM PERIOD. THE PRESSURE GRADIENT IS NOT OVERLY IMPRESSIVE AND SPEEDS WILL BE AROUND 10 KNOTS. GIVEN THE FETCH EXPECT SEAS TO RANGE FROM 2-3 FT THROUGH THE PERIOD AS WELL. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 230 PM TUESDAY...SE FLOW AROUND BERMUDA HIGH PRESSURE ON FRIDAY WILL VEER SLIGHTLY TO S FOR THE REMAINDER OF THE PERIOD AS THE HIGHS RIDGE AXIS RETREATS SLIGHTLY OUT TO SEA. OTHER THAN THAT SMALL VEER THERE SHOULD BE LITTLE VARIATION IN WIND AND/OR SEAS THROUGH MOST OF THE PERIOD AS THE HIGH REMAINS QUASI-STATIONARY. SEAS WILL BE IN THE 2 TO 4 FT RANGE WITH THE HIGHEST VALUES LOCATED OFF THE COAST. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...SRP LONG TERM...MBB AVIATION...43/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
121 PM EDT TUE MAY 28 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL BECOME WELL ESTABLISHED...BRINGING A RETURN TO SUMMERTIME HEAT INTO EARLY NEXT WEEK. SHOWERS AND THUNDERSTORMS MAY DEVELOP DURING THE HEAT OF THE DAY BY THE WEEKEND. A COLD FRONT WILL APPROACH FROM THE WEST LATE MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM TUESDAY...BEAUTIFUL DAY BEGINNING ACROSS THE CAROLINAS AS COMBINATION OF BERMUDA HIGH AND BUILDING UPPER RIDGE COMBINE TO PRODUCE PARTLY CLOUDY SKY CONDITIONS AND SEASONABLE TEMPERATURES. WV IMAGERY THIS MORNING SHOWS CLEARLY THE LARGE AREA OF HIGH PRESSURE CENTERED OFFSHORE...WITH MOISTURE AND CONVECTION ROTATING AROUND ITS PERIPHERY...FROM TEXAS TO IOWA TO PENNSYLVANIA. SE OF THIS BOUNDARY...BULGING THICKNESSES WILL CAP THE MAJORITY OF CONVECTION TODAY. HOWEVER...VERY WARM SURFACE TEMPS...LOW TO MID 80S ACROSS THE AREA...WILL CREATE ENOUGH INSTABILITY THAT PARCELS WILL BECOME BUOYANT THIS AFTN AND RISE TOWARDS THE CONVECTIVE LID. WHILE THIS HAPPENS...THE ENTIRE COLUMN BEGINS TO WARM THANKS TO INCREASING MID-LEVEL THERMAL RIDGING...SO IT WILL BE A RACE BETWEEN SURFACE BASED INSTABILITY AND MID-LEVEL WARMING TO DETERMINE WHETHER SHOWERS CAN DEVELOP TODAY. CURRENTLY...ONLY THE HRRR DEPICTS ANY SHOWERS TODAY...FOCUSED ALONG THE INLAND PENETRATING SEA BREEZE. WHILE IT IS LOGICAL THAT ONLY THE SEA BREEZE WILL BE ABLE TO TRIGGER CONVECTION STRONG ENOUGH TODAY TO PUSH THROUGH THE LID (HENCE WHY THE TERM CAP IS NOT BEING USED)...THIS MODEL HAS BEEN OVER-AGGRESSIVE THE PAST FEW DAYS. HAVE INHERITED JUST-BELOW-THRESHOLD POP...AND CHOOSE TO LEAVE UNCHANGED FOR NOW. CANNOT RULE OUT AN ISOLATED SHOWER THIS AFTN...BUT WILL HANDLE THIS WITH NEAR-TERM UPDATES AS REQUIRED. SLIGHTLY STRONGER WINDS TODAY WILL ALSO BE NOTICED AS GRADIENT IS JUST A BIT STRONGER AROUND THE OFFSHORE HIGH PRESSURE. THE STRONGEST WINDS WILL BE WITHIN THE RESULTANT THIS AFTN...WHERE WIND GUSTS TO 20 MPH WILL BE FREQUENT FOR A FEW HOURS. WINDS WILL EASE AFTER SUNSET BENEATH THE DEVELOPMENT OF THE NOCTURNAL INVERSION...BUT CONTINUED LIGHT SOUTHERLY WINDS...UP TO 15 KTS AT THE TOP OF THE INVERSION...WILL KEEP MINS ELEVATED TONIGHT AS THEY WILL FALL ONLY INTO THE MID 60S. HAVE LEFT SOME PATCHY FOG IN THE WX GRIDS SINCE CROSSOVER TEMPS MAY BE MET TONIGHT THANKS TO LONG-DURATION MOIST ADVECTION OFF THE OCEAN TODAY...BUT WIDESPREAD FOG IS NOT EXPECTED. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...BERMUDA HIGH PRESSURE WILL RIDGE BACK INTO THE CAROLINAS THROUGH MID WEEK. THIS WILL PRODUCE A WARM MOIST SOUTHERLY RETURN FLOW WITH SFC DEWPOINT TEMPS UP IN THE 60S. ALTHOUGH MORE HUMID SUMMER-LIKE CONDITIONS WILL EXIST...LOCALIZED AFTERNOON CONVECTION WILL BE SUPPRESSED BY BUILDING RIDGE ALOFT. THIS WILL KEEP VERY DRY AIR THROUGH THE LOW TO MID LEVELS BASICALLY ABOVE 4K FT. THE PCP WATER VALUES WILL ONLY BE AROUND AN INCH THROUGH THE PERIOD. EXPECT SEASONABLE TEMPS IN THE MID 80S MOST PLACES DURING THE DAY EXCEPT COOLER AT THE BEACHES. OVERNIGHT TEMPS WILL REMAIN IN THE MID 60S. MAY SEE SOME CU DEVELOP ALONG SEA BREEZE BOUNDARY AS IT PUSHES INLAND EACH DAY BUT OTHERWISE WILL SEE PLENTY OF SUNSHINE. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...BERMUDA HIGH PRESSURE WILL CONTINUE TO RIDGE BACK ACROSS THE CAROLINAS THROUGH EARLY NEXT WEEK. THE STRONG RIDGE ALOFT WILL SLIP TO THE EAST THROUGH THE WEEKEND LOSING ITS GRIP OVER THE SOUTHEAST. THIS WILL LEAD THE WAY TO INCREASED CHC OF LOCALIZED CONVECTION BUT WITHOUT MUCH FORCING ALOFT WOULD EXPECT MORE IN THE WAY OF CU BUILDING IN CONVERGENCE ALONG SEA BREEZE BOUNDARY AS IT PUSHES INLAND EACH AFTERNOON. OTHERWISE WILL CONTINUE WITH WARM AND HUMID WEATHER WITH GOOD DEAL OF SUNSHINE THROUGH THE WEEKEND. BY LATE MONDAY MID TO UPPER TROUGH WILL PUSH A COLD FRONT EAST. THEREFORE EXPECT MORE WIDESPREAD SHWR/TSTM ACTIVITY AHEAD AND ALONG THIS FRONT LATE MONDAY INTO EARLY TUESDAY. TEMPERATURES WILL BE NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD WITH OVERNIGHT LOWS IN THE MID 60S AND DAY TIME HIGHS IN THE MID TO UPPER 80S. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 18Z...BERMUDA HIGH WILL KEEP US IN SOUTHERLY FLOW THROUGH THE FORECAST PERIOD. LOOK FOR SCATTERED CU ALONG AND WEST OF THE SEA BREEZE RESULTANT THIS AFTERNOON. THE HRRR MODEL IS SHOWING SCATTERED SHOWERS...BUT FEEL THEY WILL BE ISOLATED AT BEST. SOUTH SOUTHEAST FLOW WILL DIMINISH THIS EVENING. SOME FOG IS POSSIBLE JUST BEFORE SUNRISE...BUT GIVEN THE WINDS AT THE BOUNDARY LAYER ARE AROUND 15 KTS...THINK ANY FOG WILL BE QUITE LIGHT. WEDNESDAY...CONTINUED VFR WITH MORE OF A SOUTHWEST COMPONENT. EXTENDED OUTLOOK...MORNING MVFR/ISOLATED IFR FOG THROUGH SUNDAY. ISOLATED SHOWERS SATURDAY AND SUNDAY...MAINLY WEST. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM TUESDAY...MINIMAL CHANGES WITH THIS UPDATE OTHER THAN SOME TWEAKS TO SEA-BREEZE BOUNDARY WINDS. PREVIOUS DISCUSSION BELOW: AS OF 6 AM TUESDAY...BERMUDA HIGH PRESSURE WILL DOMINATE THROUGH THE PERIOD. THE SEA BREEZE CIRCULATION WILL INTENSIFY DURING THE AFTERNOON AND EARLY EVE...THEN DISSIPATE MID TO LATE EVE. S TO SSE WINDS WILL BE STRONGEST ACROSS THE NEAR SHORE WATERS DUE TO SEA BREEZE INFLUENCES...SUSTAINED AT UP TO 15 KT AND ON THE GUSTY SIDE LATE AFTERNOON AND EARLY EVE. NO SIGNIFICANT LOW-LEVEL JETTING NOTED FOR TONIGHT AND SO WINDS SHOULD DROP OFF DURING THE LATE EVE AND OVERNIGHT. SE SWELL WILL ACTUALLY STRENGTHEN SLIGHTLY THIS PERIOD... SEAS WILL RANGE FROM 2 TO 3 FT...LARGELY THE RESULT OF AN 8 TO 9 SECOND SE SWELL. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL CONTINUE AROUND BERMUDA HIGH PRESSURE THROUGH MID WEEK. GRADIENT WILL REMAIN FAIRLY RELAXED WITH WINDS 10 KTS OR LESS BUT SPIKING UP A BIT IN SEA BREEZE EACH AFTERNOON. SEAS WILL GRADUAL BUILD FROM 1 TO 3 FT UP TO 2 TO 4 FT IN PERSISTENT SOUTH TO SOUTHEAST SWELL AROUND THE HIGH. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY...SOUTHEASTERLY RETURN FLOW WILL CONTINUE AROUND BERMUDA HIGH PRESSURE THROUGH THE PERIOD. GRADIENT WILL CONTINUE TO BE FAIRLY RELAXED WITH WINDS HOLDING AROUND 10 KTS THROUGH SATURDAY BUT INCREASING SLIGHTLY UP TO 10 TO 15 KTS BY SUNDAY. THIS PERSISTENT SOUTHERLY PUSH WILL BUILD SEA GRADUALLY UP TO 3 TO 4 FT IN THE OUTER WATERS AND CLOSER TO 2 FT NEAR SHORE. WILL SEE SPIKE IN WINDS AND SLIGHT CHOP NEAR SHORE EACH AFTERNOON IN SEA BREEZE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...RGZ LONG TERM...RGZ AVIATION...43
AREA FORECAST DISCUSSION...COR
NWS WILMINGTON NC
1018 AM EDT TUE MAY 28 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL BECOME WELL ESTABLISHED...BRINGING A RETURN TO SUMMERTIME HEAT INTO EARLY NEXT WEEK. SHOWERS AND THUNDERSTORMS MAY DEVELOP DURING THE HEAT OF THE DAY BY THE WEEKEND. A COLD FRONT WILL APPROACH FROM THE WEST LATE MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM TUESDAY...BEAUTIFUL DAY BEGINNING ACROSS THE CAROLINAS AS COMBINATION OF BERMUDA HIGH AND BUILDING UPPER RIDGE COMBINE TO PRODUCE PARTLY CLOUDY SKY CONDITIONS AND SEASONABLE TEMPERATURES. WV IMAGERY THIS MORNING SHOWS CLEARLY THE LARGE AREA OF HIGH PRESSURE CENTERED OFFSHORE...WITH MOISTURE AND CONVECTION ROTATING AROUND ITS PERIPHERY...FROM TEXAS TO IOWA TO PENNSYLVANIA. SE OF THIS BOUNDARY...BULGING THICKNESSES WILL CAP THE MAJORITY OF CONVECTION TODAY. HOWEVER...VERY WARM SURFACE TEMPS...LOW TO MID 80S ACROSS THE AREA...WILL CREATE ENOUGH INSTABILITY THAT PARCELS WILL BECOME BUOYANT THIS AFTN AND RISE TOWARDS THE CONVECTIVE LID. WHILE THIS HAPPENS...THE ENTIRE COLUMN BEGINS TO WARM THANKS TO INCREASING MID-LEVEL THERMAL RIDGING...SO IT WILL BE A RACE BETWEEN SURFACE BASED INSTABILITY AND MID-LEVEL WARMING TO DETERMINE WHETHER SHOWERS CAN DEVELOP TODAY. CURRENTLY...ONLY THE HRRR DEPICTS ANY SHOWERS TODAY...FOCUSED ALONG THE INLAND PENETRATING SEA BREEZE. WHILE IT IS LOGICAL THAT ONLY THE SEA BREEZE WILL BE ABLE TO TRIGGER CONVECTION STRONG ENOUGH TODAY TO PUSH THROUGH THE LID (HENCE WHY THE TERM CAP IS NOT BEING USED)...THIS MODEL HAS BEEN OVER-AGGRESSIVE THE PAST FEW DAYS. HAVE INHERITED JUST-BELOW-THRESHOLD POP...AND CHOOSE TO LEAVE UNCHANGED FOR NOW. CANNOT RULE OUT AN ISOLATED SHOWER THIS AFTN...BUT WILL HANDLE THIS WITH NEAR-TERM UPDATES AS REQUIRED. SLIGHTLY STRONGER WINDS TODAY WILL ALSO BE NOTICED AS GRADIENT IS JUST A BIT STRONGER AROUND THE OFFSHORE HIGH PRESSURE. THE STRONGEST WINDS WILL BE WITHIN THE RESULTANT THIS AFTN...WHERE WIND GUSTS TO 20 MPH WILL BE FREQUENT FOR A FEW HOURS. WINDS WILL EASE AFTER SUNSET BENEATH THE DEVELOPMENT OF THE NOCTURNAL INVERSION...BUT CONTINUED LIGHT SOUTHERLY WINDS...UP TO 15 KTS AT THE TOP OF THE INVERSION...WILL KEEP MINS ELEVATED TONIGHT AS THEY WILL FALL ONLY INTO THE MID 60S. HAVE LEFT SOME PATCHY FOG IN THE WX GRIDS SINCE CROSSOVER TEMPS MAY BE MET TONIGHT THANKS TO LONG-DURATION MOIST ADVECTION OFF THE OCEAN TODAY...BUT WIDESPREAD FOG IS NOT EXPECTED. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...BERMUDA HIGH PRESSURE WILL RIDGE BACK INTO THE CAROLINAS THROUGH MID WEEK. THIS WILL PRODUCE A WARM MOIST SOUTHERLY RETURN FLOW WITH SFC DEWPOINT TEMPS UP IN THE 60S. ALTHOUGH MORE HUMID SUMMER-LIKE CONDITIONS WILL EXIST...LOCALIZED AFTERNOON CONVECTION WILL BE SUPPRESSED BY BUILDING RIDGE ALOFT. THIS WILL KEEP VERY DRY AIR THROUGH THE LOW TO MID LEVELS BASICALLY ABOVE 4K FT. THE PCP WATER VALUES WILL ONLY BE AROUND AN INCH THROUGH THE PERIOD. EXPECT SEASONABLE TEMPS IN THE MID 80S MOST PLACES DURING THE DAY EXCEPT COOLER AT THE BEACHES. OVERNIGHT TEMPS WILL REMAIN IN THE MID 60S. MAY SEE SOME CU DEVELOP ALONG SEA BREEZE BOUNDARY AS IT PUSHES INLAND EACH DAY BUT OTHERWISE WILL SEE PLENTY OF SUNSHINE. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...BERMUDA HIGH PRESSURE WILL CONTINUE TO RIDGE BACK ACROSS THE CAROLINAS THROUGH EARLY NEXT WEEK. THE STRONG RIDGE ALOFT WILL SLIP TO THE EAST THROUGH THE WEEKEND LOSING ITS GRIP OVER THE SOUTHEAST. THIS WILL LEAD THE WAY TO INCREASED CHC OF LOCALIZED CONVECTION BUT WITHOUT MUCH FORCING ALOFT WOULD EXPECT MORE IN THE WAY OF CU BUILDING IN CONVERGENCE ALONG SEA BREEZE BOUNDARY AS IT PUSHES INLAND EACH AFTERNOON. OTHERWISE WILL CONTINUE WITH WARM AND HUMID WEATHER WITH GOOD DEAL OF SUNSHINE THROUGH THE WEEKEND. BY LATE MONDAY MID TO UPPER TROUGH WILL PUSH A COLD FRONT EAST. THEREFORE EXPECT MORE WIDESPREAD SHWR/TSTM ACTIVITY AHEAD AND ALONG THIS FRONT LATE MONDAY INTO EARLY TUESDAY. TEMPERATURES WILL BE NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD WITH OVERNIGHT LOWS IN THE MID 60S AND DAY TIME HIGHS IN THE MID TO UPPER 80S. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...BERMUDA HIGH WILL KEEP US IN SOUTHERLY FLOW THROUGH THE FORECAST PERIOD. FOG WAS LIGHTER THIS MORNING THAN ANTICIPATED. VFR CONDITIONS WILL PREVAIL TODAY WITH ONLY MID AND HIGH CLOUDS EXPECTED. THERE MAY BE SOME ISOLATED CU ALONG THE SEA BREEZE BOUNDARY THIS AFTERNOON. LIGHT WINDS TONIGHT WITH NEARLY CLEAR SKIES. SOME LIGHT FOG IS EXPECTED AT THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...MORNING MVFR/ISOLATED IFR FOG THROUGH SATURDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM TUESDAY...MINIMAL CHANGES WITH THIS UPDATE OTHER THAN SOME TWEAKS TO SEA-BREEZE BOUNDARY WINDS. PREVIOUS DISCUSSION BELOW: AS OF 6 AM TUESDAY...BERMUDA HIGH PRESSURE WILL DOMINATE THROUGH THE PERIOD. THE SEA BREEZE CIRCULATION WILL INTENSIFY DURING THE AFTERNOON AND EARLY EVE...THEN DISSIPATE MID TO LATE EVE. S TO SSE WINDS WILL BE STRONGEST ACROSS THE NEAR SHORE WATERS DUE TO SEA BREEZE INFLUENCES...SUSTAINED AT UP TO 15 KT AND ON THE GUSTY SIDE LATE AFTERNOON AND EARLY EVE. NO SIGNIFICANT LOW-LEVEL JETTING NOTED FOR TONIGHT AND SO WINDS SHOULD DROP OFF DURING THE LATE EVE AND OVERNIGHT. SE SWELL WILL ACTUALLY STRENGTHEN SLIGHTLY THIS PERIOD... SEAS WILL RANGE FROM 2 TO 3 FT...LARGELY THE RESULT OF AN 8 TO 9 SECOND SE SWELL. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL CONTINUE AROUND BERMUDA HIGH PRESSURE THROUGH MID WEEK. GRADIENT WILL REMAIN FAIRLY RELAXED WITH WINDS 10 KTS OR LESS BUT SPIKING UP A BIT IN SEA BREEZE EACH AFTERNOON. SEAS WILL GRADUAL BUILD FROM 1 TO 3 FT UP TO 2 TO 4 FT IN PERSISTENT SOUTH TO SOUTHEAST SWELL AROUND THE HIGH. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY...SOUTHEASTERLY RETURN FLOW WILL CONTINUE AROUND BERMUDA HIGH PRESSURE THROUGH THE PERIOD. GRADIENT WILL CONTINUE TO BE FAIRLY RELAXED WITH WINDS HOLDING AROUND 10 KTS THROUGH SATURDAY BUT INCREASING SLIGHTLY UP TO 10 TO 15 KTS BY SUNDAY. THIS PERSISTENT SOUTHERLY PUSH WILL BUILD SEA GRADUALLY UP TO 3 TO 4 FT IN THE OUTER WATERS AND CLOSER TO 2 FT NEAR SHORE. WILL SEE SPIKE IN WINDS AND SLIGHT CHOP NEAR SHORE EACH AFTERNOON IN SEA BREEZE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...RGZ LONG TERM...RGZ AVIATION...43
AREA FORECAST DISCUSSION
NWS BISMARCK ND
938 PM CDT WED MAY 29 2013 .UPDATE... ISSUED AT 938 PM CDT WED MAY 29 2013 ONCE AGAIN...GIVEN THE LATEST RADAR TRENDS...THE 18 AND INCOMING 00 UTC DETERMINISTIC GUIDANCE AND 01 UTC RAP/HRRR SIMULATED REFLECTIVITY FORECASTS...REDUCED POPS THROUGH 06 UTC FOR MUCH OF THE AREA UNTIL THE ARRIVAL OF GREATER UPPER LEVEL FORCING AS CONVECTION ACROSS SOUTH DAKOTA THROUGH NEBRASKA MAY ALSO BE DISRUPTING MOISTURE TRANSPORT INTO NORTH DAKOTA. DO NOT ANTICIPATE SEVERE WEATHER TONIGHT ACROSS WESTERN AND CENTRAL NORTH DAKOTA...WITH A POTENTIAL RETURN OF THE THREAT TOMORROW AFTERNOON AND EVENING DEPENDENT UPON HOW MUCH CLEARING/INSOLATION IS ACHIEVED IN THE WARM SECTOR OF THE SURFACE LOW ACROSS SOUTH CENTRAL NORTH DAKOTA. UPDATE ISSUED AT 720 PM CDT WED MAY 29 2013 THE BIGGEST CHANGE WITH THIS UPDATE WAS TO REDUCE POPS...ESPECIALLY ALONG AND NORTH OF US HIGHWAY 2...GIVEN THE LATEST RADAR TRENDS AND THE 21 UTC HRRR SIMULATED REFLECTIVITY WHICH HAS MAINTAINED CONTINUITY WITH PREVIOUS RUNS WHICH KEEP MUCH OF NORTHERN NORTH DAKOTA PRECIPITATION FREE THROUGH AT LEAST 06 UTC. GIVEN THE MARGINAL INSTABILITY AND SHEAR...THE SMALL WINDOW FOR SEVERE HAIL AND/OR WINDS ACROSS THE JAMES RIVER VALLEY APPEARS TO BE QUICKLY CLOSING AND WILL FOCUS ON HEAVY RAIN MONITORING OVER THE SATURATED AREAS OF SOUTHERN NORTH DAKOTA. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 405 PM CDT WED MAY 29 2013 MAIN PROBLEM IN THE SHORT TERM PERIOD WILL BE PRECIPITATION AMOUNTS...PLACEMENT AND TIMING. CURRENTLY...SURFACE LOW PRESSURE OVER THE CENTRAL PLAINS WITH A WARM FRONT EXTENDING INTO EASTERN SOUTH DAKOTA AND SOUTHERN MINNESOTA. STRONG NEGATIVELY TILTED UPPER LEVEL TROUGH FROM THE NORTHWEST U.S. INTO THE CENTRAL ROCKIES. CURRENT CONVECTION IN OUR AREA IS LINING UP WITH THE THE STRONG WARM ADVECTION OVER THE EASTERN DAKOTAS INTO MINNESOTA...AS WELL AS STRONG UPPER LEVEL DIVERGENCE OVER EASTERN MONTANA. TONIGHT...THE UPPER LEVEL WAVE WILL LIFT NORTHWARD INTO THE NORTHERN HIGH PLAINS WITH THE SURFACE LOW TRACKING NORTH THROUGH SOUTH DAKOTA. THIS WILL BRING INCREASING SHOWERS AND POSSIBLY SOME THUNDERSTORMS TO WESTERN AND CENTRAL NORTH DAKOTA. ALTHOUGH WE DO THINK MOST AREAS WILL RECEIVE PRECIPITATION...WE HAVE CONTINUED THE TREND OF DELAYING THE ONSET...AND CUTTING BACK A LITTLE ON THE AMOUNTS. AGAIN..WE ARE IN A BIT OF A LULL BETWEEN THE STRONG WARM ADVECTION TO OUR EAST...AND THE STRONG FORCING AND DIVERGENT FLOW ALOFT ASSOCIATED WITH THE UPPER LEVEL SYSTEM TO OUR WEST. THURSDAY...THE UPPER LEVEL LOW CONTINUES TO LIFT NORTH THROUGH EASTERN MONTANA...WHILE THE SURFACE LOW LIFTS NORTH TO NEAR BISMARCK...THEN NORTHWEST TOWARDS WILLISTON. THIS PLACEMENT WOULD BRING GREATEST PRECIPITATION AMOUNTS TO THE NORTHERN HALF OF THE CWA...WITH DRIER AIR WORKING FROM SOUTH TO NORTH THURSDAY AFTERNOON. THIS WOULD BRING AN END TO PRECIPITATION ACROSS THE SOUTH HALF OF THE CWA...BUT COULD ALSO ALLOW FOR A PERIOD OF DESTABILIZATION THURSDAY AFTERNOON IN THE DRIER AIR. WITH THE SURFACE AND UPPER LOWS JUST WEST...THIS WOULD INCREASE THE RISK OF THUNDERSTORMS IN A HIGH SHEAR ENVIRONMENT. DUE TO SOME MODEL AND TIMING UNCERTAINTIES WILL NOT MENTION SEVERE AT THIS TIME...AND LET LATER SHIFTS UPDATE AS NEEDED. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 405 PM CDT WED MAY 29 2013 WET AND COOL WEATHER REMAINS OVER THE NORTHERN PLAINS THROUGH EARLY SATURDAY...FOLLOWED BY QUIET CONDITIONS SATURDAY THROUGH SUNDAY AFTERNOON...THEN A RETURN TO ACTIVE CONDITIONS SUNDAY NIGHT THROUGH TUESDAY. THE LONG TERM BEGINS THURSDAY EVENING WITH A CLOSED UPPER LEVEL LOW CENTERED OVER SOUTHWEST ND/SOUTHEASTERN MONTANA...AND AN AREA OF SURFACE LOW PRESSURE OVER WESTERN NORTH DAKOTA. ACTIVE WEATHER WILL BE ONGOING AT THE START OF THE PERIOD WITH WIDESPREAD RAIN SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE NORTH AND FAR WEST WRAPPING AROUND THE UPPER LOW. OVER SOUTH CENTRAL AND SOUTHEASTERN NORTH DAKOTA...A DRY SLOT IS EXPECTED TO PROVIDE SOME CLEARING THURSDAY AFTERNOON INTO THURSDAY EVENING...WITH THE RESULTANT HEATING ACTING TO INCREASE SURFACE INSTABILITY WITH UPWARDS TO NEAR 1500 J/KG OF CAPE FORECAST NEAR A SFC COLD/OCCLUDED FRONT. MAY SEE ISOLATED SEVERE STORMS DEVELOP GIVEN THE ADVERTISED INSTABILITY PERSISTING INTO THE EVENING NEAR THE BOUNDARY. LOW LINGERS ACROSS THE NORTHERN PLAINS THROUGH FRIDAY BEFORE MORPHING INTO AN OPEN WAVE AND PUSHING OFF TO OUR EAST SATURDAY AFTERNOON. AS THIS OCCURS...WILL SEE WRAP AROUND PRECIPITATION SPREAD FROM WEST TO EAST FRIDAY MORNING THROUGH FRIDAY EVENING...THEN DECREASING CLOUDS AND CHANCES FOR RAIN FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT INTO SATURDAY. OVERALL EXPECT UPWARDS TO AN ADDITIONAL ONE HALF INCH OF RAINFALL THURSDAY NIGHT THROUGH SATURDAY MORNING ACROSS WEST AND CENTRAL ND. DRY WEATHER REMAINS IN THE FORECAST SATURDAY NIGHT THROUGH SUNDAY AFTERNOON WITH A SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE BUILDING EAST ACROSS THE NORTHERN PLAINS. ACTIVE WEATHER RESUMES SUNDAY NIGHT INTO EARLY NEXT WEEK AS ANOTHER UPPER LOW/TROUGH PUSHES ACROSS THE NORTHERN ROCKIES AND EVENTUALLY INTO THE NORTHERN PLAINS. WELL BELOW NORMAL TEMPERATURES FRIDAY AND SATURDAY WITH HIGHS 55-65 AND LOWS IN THE UPPER 30S TO MID 40S. WILL NEED TO MONITOR FOR POSSIBLE FROST SATURDAY NIGHT/SUNDAY MORNING WHEN WINDS ARE EXPECTED TO BE LIGHT...SKIES CLEAR...AND SFC DEWPOINT TEMPS FORECAST TO FALL AS LOW AS 35F DEGREES SOME AREAS. DAYTIME AND NIGHTTIME TEMPERATURES MODERATE TOWARDS NORMAL SUNDAY-TUESDAY WITH HIGHS GENERALLY IN THE 60S AND LOW 45-55. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY) ISSUED AT 938 PM CDT WED MAY 29 2013 SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE NIGHT...WITH FLIGHT CONDITIONS TRENDING TOWARDS IFR AT KDIK...KMOT AND KISN IN MODERATE RAIN LATE TONIGHT...AND MVFR AT KBIS AND KJMS. DEPENDING ON HOW MUCH CLEARING THERE IS THURSDAY AFTERNOON...STRONG TO SEVERE THUNDERSTORMS MAY BE POSSIBLE FOR THE KDIK...KBIS AND KJMS TAF SITES THURSDAY AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 405 PM CDT WED MAY 29 2013 SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON AND TONIGHT...AND MOVE FROM SOUTH TO NORTH ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THURSDAY AFTERNOON. THE POTENTIAL FOR HEAVY RAIN EXISTS ACROSS THE WEST AND CENTRAL... ESPECIALLY LATE TONIGHT THROUGH THURSDAY. WIDESPREAD RAINFALL AMOUNTS OF THREE QUARTERS OF AN INCH...TO TWO INCHES ARE FORECAST THOUGH THIS PERIOD. HOWEVER...THE LATEST GUIDANCE CONTINUES TO SUGGEST A LESS LIKELY SCENARIO FOR AMOUNTS GREATER THAN 1.5 INCHES OVER MUCH OF THE CENTRAL. THE MOST LIKELY AREAS FOR THE HIGHEST AMOUNTS APPEAR TO BE IN THE FAR NORTH AND FAR WEST...WITH THE HIGHEST AMOUNTS IN EASTERN MONTANA AND SOUTHERN CANADA. STREAM AND RIVER RISES ARE POSSIBLE BY THE END OF THE WEEK INTO THIS COMING WEEKEND. AN ADDITIONAL ONE QUARTER TO ONE HALF INCH WILL BE POSSIBLE FRIDAY AND FRIDAY NIGHT. CHANCES FOR RAIN DECREASE SATURDAY INTO SATURDAY NIGHT. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...TWH LONG TERM...NH AVIATION...AYD HYDROLOGY...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
730 PM CDT WED MAY 29 2013 .UPDATE... ISSUED AT 716 PM CDT WED MAY 29 2013 MAIN CHALLENGE WITH UPDATE IS POP TIMNG AND WHAT CHANGES TO MAKE. OVERALL LEAD SHORT WAVE PRODUCING AREA OF SHOWERS AND ISOLD THUNDER FROM SE ND INTO NRN MN. THIS ACTIVITY HAS CONTINUED TO MOVE NORTHEAST PAST SEVERAL HOURS AND SHOULD REMAIN SOUTHOF A BDE- GFK LINE. NORTHWEST OF THIS AREA GENERALLY DRY AND LOOKS LIKE IT SHOULD REMAIN SO THRU 06Z. OTHER ISOLD CELLS POPPING UP IN ERN SD SOUTHEAST OF ABERDEEN OVER TOWARD MILBANK. THIS WILL MOVE NORTH- NORTHEAST AS WELL. FOR THE TONIGHT TRENDS IN PRECIP...NOT REAL SURE WHAT TO EXPECT. 850 MB LOW LEVEL JET IS REALLY FOCUSED OVER ERN KS INTO WRN IOWA EARLY EVE WITH 35 KTS OR SO INTO FAR ERN SD/WCNTRL MN EARLY THIS EVE. THEN THE LOW LEVEL JET INTENSIFIES BUT ALSO SHIFTS MORE EAST WITH MAIN AXIS FROM ERN KS THRU IOWA INTO SE MN/WI. THUS THIS MIGHT SUGGEST MAIN ACTION TO REMAIN SOUTH AND SOUTHEAST OF OUR REGION. CURRENTLY LARGE SVR MCS MOVING INTO SW WISCONSIN WITH HVY RAIN IN SE MN/NE IA. ALSO GOT SECOND AREA OF RAIN MORE SO NORTH OF UPPER LOW WHICH IS IN EAST CENTRAL WYOMING FROM NW SD INTO CNTRL MT. UPPER LOW WILL LIFT NORTH SLOWLY TONIGHT INTO THURSDAY INTO WRN ND KEEPING ERN MT VERY WET. HOW MUCH RAIN OCCURS IN CNTRL-ERN ND INTO NW/WCNTRL MN TONIGHT INTO THURSDAY IN BETWEEN UPPER LEVEL LOW DYNAMICS AND LOW LEVEL JET IS A BIT SUSPECT. FOR THE TIME BEING WILL GO MOSTLY SCT THUNDER IN SE ND/WCNTRL MN THIS EVE THEN KEEP IDEA OF LIKELY POPS MOST AREAS AFTER 06Z. SEVERE THREAT LOOKS A BIT LOW ATTM... BUT NOT IMPOSSIBLE IN THE NEXT FEW HOURS ON EDGE OF LOW LEVEL JET IN FAR ECNTRL SD INTO WCNTRL MN. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 255 PM CDT WED MAY 29 2013 A LEAD SHORTWAVE COMING OFF THE MAIN TROUGH CONTINUES TO LIFT NORTHEASTWARD THROUGH THE DAKOTAS. THE SHORTWAVE ALONG WITH THE 850MB JET NOSING INTO THE AREA HAS HELPED SET OFF SHOWERS AND A FEW THUNDERSTORMS OVER MAINLY THE SOUTHERN CWA THIS AFTERNOON. CLOUDS AND COOLER TEMPS HAVE KEPT INSTABILITY MINIMIZED ACROSS THE SOUTHERN CWA BUT SPC MESOANALYSIS HAS SOME CAPE AROUND 1000 J/KG JUST TO THE NORTH ACROSS THE CENTRAL CWA. THE VERY UNSTABLE AIR IS STILL WELL TO OUR SOUTH OVER SD. MODELS HAVE THE CAPE INCREASING OVER OUR SOUTHERN CWA LATER THIS EVENING...BUT BULK SHEAR IS STILL ONLY AROUND 20 KTS. THINK THAT THERE WILL BE THE POSSIBILITY OF SOME SEVERE HAIL OR WINDS...BUT BETTER CHANCES WILL BE FURTHER SOUTH OR TOMORROW. THE SHORTWAVE WILL CONTINUE TO LIFT NORTHEASTWARD OVERNIGHT AND SPREAD RAINFALL TOWARDS THE CANADIAN BORDER. THE TROUGH ENTERING THE CENTRAL PLAINS TONIGHT WILL CLOSE OFF AND CONTINUE NORTHEASTWARD INTO THE WY/MT AREA AND WESTERN DAKOTAS BY TOMORROW. THE SFC LOW WILL CONTINUE TO DEEPEN AND LIFT INTO SOUTHERN ND...WITH A WARM FRONT PUSHING INTO THE CWA. HOW MUCH WE DESTABILIZE WILL DEPEND ON HOW MUCH CLEARING OCCURS TOMORROW AFTERNOON. THE NAM HAS AROUND 1300 J/KG IN SOME AREAS BUT LIKE TODAY HAS SOME PLACES WITH REDUCED INSTABILITY DUE TO CLOUDS AND PRECIP. THE GFS HAS A MORE WIDESPREAD AREA OF MORE THAN 1500 J/KG. BOTH MODELS HAVE MORE SIGNIFICANT SHEAR AND WITH THE SFC BOUNDARY IN THE AREA THINK THAT THERE WILL BE A GOOD CHANCE FOR SEVERE STORMS TOMORROW AFTERNOON AND EVENING. THE UPPER LOW WILL CONTINUE OVER THE DAKOTAS THURSDAY NIGHT...WITH THE BULK OF THE PRECIP MOVING INTO THE NORTHERN CWA DURING THE OVERNIGHT HOURS AS THE WARM FRONT MOVES TOWARDS THE CANADIAN BORDER. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 255 PM CDT WED MAY 29 2013 FRIDAY...THE MODELS SEEM TO BE IN FAIRLY DECENT AGREEMENT ON THE DRY SLOT MOVING INTO THE SOUTHERN COUNTIES. LOWERED POPS A BIT IN THAT AREA. THE UPPER LOW WILL FINALLY BEGIN TO MOVE EASTWARD FRIDAY AND FRIDAY NIGHT. THIS WILL HELP PUSH THE SFC LOW INTO MN AND DROP A COLD FRONT INTO THE CWA. THE FRONT WILL BE THROUGH THE WESTERN CWA BY FRIDAY AFTERNOON AND ACROSS THE ENTIRE AREA FRIDAY NIGHT. INCREASED POPS AGAIN IN THE SOUTH AS THE COLD FRONT MOVES IN. TEMPS SHOULD DROP DOWN INTO THE 60S FOR HIGHS AND 40S TO LOW 50S FOR LOWS. EARLY IN THE PERIOD...SHORT WAVES WILL CONTINUE TO ROTATE AROUND UPPER LOW PROGGED TO BE OVER UPPER GREAT LAKES. THIS WILL CONTINUE CHANCES FOR RAIN SHOWERS THROUGH THE DAY SATURDAY. MODELS IN GENERAL AGREEMENT HOWEVER GFS PUTS ASSOCIATED SFC LOW FURTHER EAST. SHORT WAVE RIDGE THEN SETS UP FOR SUNDAY AND SHOULD SEE DRY WEATHER BEFORE NEXT ROUND OF SHOWERS/TSTMS MOVES IN AS AN UPPER LOW TRANSITS SOUTHERN SASK/MANITOBA. STILL SOME DIFFERENCES IN POSITION OF UPPER LOW (ECMWF FURTHER NORTH) HOWEVER SIMILAR SOLUTIONS FOR PLACEMENT OF PRECIP ACROSS OUR CWA MON NIGHT INTO TUE. CONSALL SOLUTION TRENDING TOWARD LIKELY POPS...WHICH SEEMS REASONABLE ALTHOUGH LIKELY TO WIDESPREAD THIS FAR OUT. AN ACTIVE PERIOD FOR NEXT WEEK NONETHELESS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 716 PM CDT WED MAY 29 2013 GNERAL IDEA FROM HRRR IS TO BRING UP OR DEVELOP MVFR CLOUD COVER INTO THE FCST AREA OVERNIGHT INTO THURSDAY MORNING AS DEW PTS ARE IN THE UPPER 50S TO LOWER 60S. SOME HIGHER DEW PTS IN SD AND WCNTRL MN WITH A FEW SPOTS NR 70 MAY MOVE NORTH AS WELL. IN THESE SITUATIONS HAVE OFTEN SEEN LOW LEVEL CLOUD COVER SPREADING OR DEVELOPING NORTH LATE NIGHT INTO THE MORNING. KEPT SHOWERS IN FARGO-BEMIDJI THIS EVE THEN BROUGHT MORE PREDOMINATE SHOWERS GFK- DVL-TVF MOSTLY AFTER 06Z INTO THU MID MORNING. BUT TIMING OF PRECIP UNCERTAIN. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...RIDDLE SHORT TERM...JR LONG TERM...JR/SPEICHER AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
720 PM CDT WED MAY 29 2013 .UPDATE... ISSUED AT 720 PM CDT WED MAY 29 2013 THE BIGGEST CHANGE WITH THIS UPDATE WAS TO REDUCE POPS...ESPECIALLY ALONG AND NORTH OF US HIGHWAY 2...GIVEN THE LATEST RADAR TRENDS AND THE 21 UTC HRRR SIMULATED REFLECTIVITY WHICH HAS MAINTAINED CONTINUITY WITH PREVIOUS RUNS WHICH KEEP MUCH OF NORTHERN NORTH DAKOTA PRECIPITATION FREE THROUGH AT LEAST 06 UTC. GIVEN THE MARGINAL INSTABILITY AND SHEAR...THE SMALL WINDOW FOR SEVERE HAIL AND/OR WINDS ACROSS THE JAMES RIVER VALLEY APPEARS TO BE QUICKLY CLOSING AND WILL FOCUS ON HEAVY RAIN MONITORING OVER THE SATURATED AREAS OF SOUTHERN NORTH DAKOTA. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 405 PM CDT WED MAY 29 2013 MAIN PROBLEM IN THE SHORT TERM PERIOD WILL BE PRECIPITATION AMOUNTS...PLACEMENT AND TIMING. CURRENTLY...SURFACE LOW PRESSURE OVER THE CENTRAL PLAINS WITH A WARM FRONT EXTENDING INTO EASTERN SOUTH DAKOTA AND SOUTHERN MINNESOTA. STRONG NEGATIVELY TILTED UPPER LEVEL TROUGH FROM THE NORTHWEST U.S. INTO THE CENTRAL ROCKIES. CURRENT CONVECTION IN OUR AREA IS LINING UP WITH THE THE STRONG WARM ADVECTION OVER THE EASTERN DAKOTAS INTO MINNESOTA...AS WELL AS STRONG UPPER LEVEL DIVERGENCE OVER EASTERN MONTANA. TONIGHT...THE UPPER LEVEL WAVE WILL LIFT NORTHWARD INTO THE NORTHERN HIGH PLAINS WITH THE SURFACE LOW TRACKING NORTH THROUGH SOUTH DAKOTA. THIS WILL BRING INCREASING SHOWERS AND POSSIBLY SOME THUNDERSTORMS TO WESTERN AND CENTRAL NORTH DAKOTA. ALTHOUGH WE DO THINK MOST AREAS WILL RECEIVE PRECIPITATION...WE HAVE CONTINUED THE TREND OF DELAYING THE ONSET...AND CUTTING BACK A LITTLE ON THE AMOUNTS. AGAIN..WE ARE IN A BIT OF A LULL BETWEEN THE STRONG WARM ADVECTION TO OUR EAST...AND THE STRONG FORCING AND DIVERGENT FLOW ALOFT ASSOCIATED WITH THE UPPER LEVEL SYSTEM TO OUR WEST. THURSDAY...THE UPPER LEVEL LOW CONTINUES TO LIFT NORTH THROUGH EASTERN MONTANA...WHILE THE SURFACE LOW LIFTS NORTH TO NEAR BISMARCK...THEN NORTHWEST TOWARDS WILLISTON. THIS PLACEMENT WOULD BRING GREATEST PRECIPITATION AMOUNTS TO THE NORTHERN HALF OF THE CWA...WITH DRIER AIR WORKING FROM SOUTH TO NORTH THURSDAY AFTERNOON. THIS WOULD BRING AN END TO PRECIPITATION ACROSS THE SOUTH HALF OF THE CWA...BUT COULD ALSO ALLOW FOR A PERIOD OF DESTABILIZATION THURSDAY AFTERNOON IN THE DRIER AIR. WITH THE SURFACE AND UPPER LOWS JUST WEST...THIS WOULD INCREASE THE RISK OF THUNDERSTORMS IN A HIGH SHEAR ENVIRONMENT. DUE TO SOME MODEL AND TIMING UNCERTAINTIES WILL NOT MENTION SEVERE AT THIS TIME...AND LET LATER SHIFTS UPDATE AS NEEDED. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 405 PM CDT WED MAY 29 2013 WET AND COOL WEATHER REMAINS OVER THE NORTHERN PLAINS THROUGH EARLY SATURDAY...FOLLOWED BY QUIET CONDITIONS SATURDAY THROUGH SUNDAY AFTERNOON...THEN A RETURN TO ACTIVE CONDITIONS SUNDAY NIGHT THROUGH TUESDAY. THE LONG TERM BEGINS THURSDAY EVENING WITH A CLOSED UPPER LEVEL LOW CENTERED OVER SOUTHWEST ND/SOUTHEASTERN MONTANA...AND AN AREA OF SURFACE LOW PRESSURE OVER WESTERN NORTH DAKOTA. ACTIVE WEATHER WILL BE ONGOING AT THE START OF THE PERIOD WITH WIDESPREAD RAIN SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE NORTH AND FAR WEST WRAPPING AROUND THE UPPER LOW. OVER SOUTH CENTRAL AND SOUTHEASTERN NORTH DAKOTA...A DRY SLOT IS EXPECTED TO PROVIDE SOME CLEARING THURSDAY AFTERNOON INTO THURSDAY EVENING...WITH THE RESULTANT HEATING ACTING TO INCREASE SURFACE INSTABILITY WITH UPWARDS TO NEAR 1500 J/KG OF CAPE FORECAST NEAR A SFC COLD/OCCLUDED FRONT. MAY SEE ISOLATED SEVERE STORMS DEVELOP GIVEN THE ADVERTISED INSTABILITY PERSISTING INTO THE EVENING NEAR THE BOUNDARY. LOW LINGERS ACROSS THE NORTHERN PLAINS THROUGH FRIDAY BEFORE MORPHING INTO AN OPEN WAVE AND PUSHING OFF TO OUR EAST SATURDAY AFTERNOON. AS THIS OCCURS...WILL SEE WRAP AROUND PRECIPITATION SPREAD FROM WEST TO EAST FRIDAY MORNING THROUGH FRIDAY EVENING...THEN DECREASING CLOUDS AND CHANCES FOR RAIN FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT INTO SATURDAY. OVERALL EXPECT UPWARDS TO AN ADDITIONAL ONE HALF INCH OF RAINFALL THURSDAY NIGHT THROUGH SATURDAY MORNING ACROSS WEST AND CENTRAL ND. DRY WEATHER REMAINS IN THE FORECAST SATURDAY NIGHT THROUGH SUNDAY AFTERNOON WITH A SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE BUILDING EAST ACROSS THE NORTHERN PLAINS. ACTIVE WEATHER RESUMES SUNDAY NIGHT INTO EARLY NEXT WEEK AS ANOTHER UPPER LOW/TROUGH PUSHES ACROSS THE NORTHERN ROCKIES AND EVENTUALLY INTO THE NORTHERN PLAINS. WELL BELOW NORMAL TEMPERATURES FRIDAY AND SATURDAY WITH HIGHS 55-65 AND LOWS IN THE UPPER 30S TO MID 40S. WILL NEED TO MONITOR FOR POSSIBLE FROST SATURDAY NIGHT/SUNDAY MORNING WHEN WINDS ARE EXPECTED TO BE LIGHT...SKIES CLEAR...AND SFC DEWPOINT TEMPS FORECAST TO FALL AS LOW AS 35F DEGREES SOME AREAS. DAYTIME AND NIGHTTIME TEMPERATURES MODERATE TOWARDS NORMAL SUNDAY-TUESDAY WITH HIGHS GENERALLY IN THE 60S AND LOW 45-55. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY) ISSUED AT 720 PM CDT WED MAY 29 2013 SCATTERED SHOWERS AND THUNDERSTORMS IN THE KDIK AND KJMS VICINITIES WILL INCREASE IN COVERAGE ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE NIGHT...WITH FLIGHT CONDITIONS TRENDING TOWARDS IFR AT KDIK...KMOT AND KISN IN MODERATE RAIN LATE TONIGHT...AND MVFR AT KBIS AND KJMS. DEPENDING ON HOW MUCH CLEARING THERE IS THURSDAY AFTERNOON...STRONG TO SEVERE THUNDERSTORMS MAY BE POSSIBLE FOR THE KDIK...KBIS AND KJMS TAF SITES THURSDAY AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 405 PM CDT WED MAY 29 2013 SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON AND TONIGHT...AND MOVE FROM SOUTH TO NORTH ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THURSDAY AFTERNOON. THE POTENTIAL FOR HEAVY RAIN EXISTS ACROSS THE WEST AND CENTRAL... ESPECIALLY LATE TONIGHT THROUGH THURSDAY. WIDESPREAD RAINFALL AMOUNTS OF THREE QUARTERS OF AN INCH...TO TWO INCHES ARE FORECAST THOUGH THIS PERIOD. HOWEVER...THE LATEST GUIDANCE CONTINUES TO SUGGEST A LESS LIKELY SCENARIO FOR AMOUNTS GREATER THAN 1.5 INCHES OVER MUCH OF THE CENTRAL. THE MOST LIKELY AREAS FOR THE HIGHEST AMOUNTS APPEAR TO BE IN THE FAR NORTH AND FAR WEST...WITH THE HIGHEST AMOUNTS IN EASTERN MONTANA AND SOUTHERN CANADA. STREAM AND RIVER RISES ARE POSSIBLE BY THE END OF THE WEEK INTO THIS COMING WEEKEND. AN ADDITIONAL ONE QUARTER TO ONE HALF INCH WILL BE POSSIBLE FRIDAY AND FRIDAY NIGHT. CHANCES FOR RAIN DECREASE SATURDAY INTO SATURDAY NIGHT. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...TWH LONG TERM...NH AVIATION...TWH HYDROLOGY...TWH
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
110 PM CDT TUE MAY 28 2013 .UPDATE... ISSUED AT 110 PM CDT TUE MAY 28 2013 BAND OF LIGHT RAIN SHOWERS HAS MOVED INTO NORTHWEST MN AND WILL SHIFT HIGHER CHANCE POPS INTO THIS REGION FOR THE REST OF THE AFTERNOON. ALONG AND WEST OF THE VALLEY...DID ADD SOME 30 POPS WITHIN THE BROADER AREA OF 20S. CLOUDS HAVE BECOME SCATTERED- BROKEN WEST OF A LINE FROM LANGDON TO VALLEY CITY AND THINK SURFACE HEATING AND CYCLONIC FLOW ALOFT SHOULD RESULT IN ADDITIONAL SHOWER DEVELOPMENT LATE AFTERNOON. KEPT THESE 20-30 POPS INTO THE EARLY EVENING ACROSS THE DEVILS LAKE BASIN...BUT THINK ALL ACTIVITY SHOULD FALL APART BY 03 UTC. ALSO ADDED ISOLATED THUNDER TO WEATHER GRIDS HAVING OBSERVED A COUPLE LIGHTNING STRIKES NORTH OF THE BORDER. WITH THICK CLOUD COVER TAKING MORE TIME TO PUSH EAST/DISSIPATE... LOWERED TEMPERATURES ACROSS THE FORECAST AREA ANOTHER 2 TO 4 DEGREES. AREAS THAT REACH THE LOW 70S WILL BE ACROSS EASTERN ND WITH MOST OF NORTHWEST AND WEST CENTRAL MN STAYING IN THE 60S. UPDATE ISSUED AT 1004 AM CDT TUE MAY 28 2013 15 UTC REGIONAL RADAR SHOWS A NARROW BAND OF LIGHT SHOWERS ACROSS NORTHEAST ND...MOVING INTO CANADA AROUND 20 MPH. ANY ADDITIONAL ISOLATED TO SCATTERED SHOWERS THROUGH THE DAY WILL BE CONFINED MAINLY TO EASTERN ND AS DEPICTED BY THE LATEST SUITE OF MODELS. SHOULD SEE SOME BREAKS IN THE CLOUDS ALONG AND WEST OF THE VALLEY LATE THIS MORNING AND THROUGH THE AFTERNOON...BUT OVERCAST SKIES EXPECTED TO PERSIST ACROSS MUCH OF NORTHWEST AND WEST CENTRAL MN THROUGH THE DAY. AS A RESULT...DID DROP TEMPERATURES A FEW DEGREES ACROSS WEST CENTRAL MN WITH HIGHS IN THE MID TO UPPER 60S. ALL OTHER AREAS SHOULD SEE ENOUGH SUN TO CLIMB INTO THE LOWER 70S. MODEST SOUTHERLY WIND WILL GRADUALLY WEAKEN AND SHIFT TO THE WEST THIS EVENING AND OVERNIGHT AS THE MAIN SURFACE TROUGH MOVES ACROSS THE REGION. OVERALL...FORECAST IS IN GOOD SHAPE WITH NO MAJOR CHANGES AT THIS TIME. UPDATE ISSUED AT 638 AM CDT TUE MAY 28 2013 SHORTWAVE TROUGH IS SWINGING THROUGH THE FA AND ASSOCIATED FORCING IS CAUSING SHOWERS TO DEVELOP WITHIN THE DEVILS LAKE BASIN. EXPECT THIS ACTIVITY TO PROPAGATE TO THE NORTHEAST ALONG WITH THE UPPER WAVE. INCREASED POPS TO HIGH CHANCE CATEGORY FOR THIS ACTIVITY. STILL EXPECT SOME CLEARING ACROSS THE WESTERN FA BY THIS AFTERNOON. THIS SHOULD ALLOW ENOUGH HEATING TO COMBINE WITH UPPER JET STREAK FOR ISOLATED SHOWERS...WHICH THE HRRR CONTINUES TO INDICATE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 347 AM CDT TUE MAY 28 2013 THERE ARE A COUPLE UPPER LEVEL SHORTWAVES ACROSS EASTERN AND NORTHERN NORTH DAKOTA THAT WILL CONTINUE TO PROPAGATE TO THE NORTHEAST TODAY. WILL KEEP THE ISOLD-SCATTERED SHOWERS THROUGH THE MORNING HOURS ACROSS THE NE FA. HRRR/RAP/4-KM WRF MODELS INDICATE THE POTENTIAL FOR ISOLD SHOWERS ALONG AND WEST OF THE VALLEY THIS AFTERNOON AS HEATING COMBINES WITH AN UPPER LEVEL JET STREAK. OTHERWISE...THIS PERIOD WILL BE MOSTLY DRY AS RIDGING AFFECTS THE AREA TONIGHT INTO TUESDAY AND MUCH OF WEDNESDAY. THUNDER CHANCES INCREASE BY LATER WEDNESDAY AFTERNOON ACROSS THE SOUTHERN FA. TEMPERATURES SHOULD BE NEAR NORMAL VALUES AS CLOUD COVER IS EXPECTED TO BE MORE SCATTERED THAN THE PAST COUPLE DAYS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 347 AM CDT TUE MAY 28 2013 WEDNESDAY NIGHT-THURSDAY NIGHT... SEVERE POTENTIAL AND HEAVY RAIN POTENTIAL WILL BE THE MAIN CONCERNS. ALTHOUGH MODELS HAVE HAVE A SIMILAR IDEA...THERE ARE DIFFERENCES WITH THE LEAD SHORTWAVE AND POTENTIAL IMPACTS WEDNESDAY EVENING INTO THURSDAY MORNING. ECMWF IS THE PREFERRED MODEL AS PER THE PMDHMD. FOR WED NIGHT...THERE WILL LIKELY BE A SURGE OF INSTABILITY AS AN ELEVATED WARM FRONT PROPAGATES NORTHWARD THROUGH THE FA. SEVERE POTENTIAL WILL DEPEND ON THE STRENGTH OF THE LOW LEVEL JET...THE ECMWF IS AROUND 40 KNOTS. DEEP LAYER SHEAR AND INSTABILITY WILL BE MARGINAL...AND CAN IMAGINE A FEW SEVERE STORMS...BUT NOT AN OUTBREAK SCENARIO. SHOWER AND THUNDERSTORM CHANCES CONTINUE INTO THURSDAY AS THE REGION REMAINS IN WARM AIR ADVECTION REGIME. THESE CHANCES END FROM WEST TO EAST THURSDAY AFTERNOON AND EVENING AS A COLD FRONT AND STABLE AIRMASS MOVE INTO THE REGION. IT IS BECOMING MORE LIKELY THAT THE UPPER LOW WILL CLOSE OFF WITHIN NORTH DAKOTA...WITH THE BOUNDARY STALLING NORTH OF THE INTERNATIONAL BORDER. THE MAIN HEAVY RAIN THREAT WILL BE WHERE EVER THIS BOUNDARY STALLS. HOWEVER...PWATS WILL INCREASE TO AROUND 1.5 INCHES WED NIGHT...AND THE POTENTIAL WILL EXIST FOR ISOLATED HEAVY RAINFALL. THIS POTENTIAL WILL BE GREATEST WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED (NOSE OF LOW LEVEL JET)...AND WILL MENTION LOCALLY HEAVY RAINFALL POSSIBLE FOR AREAS WEST OF THE VALLEY. FRIDAY-MONDAY... MODELS IN GOOD AGREEMENT WITH PLACEMENT AND EVOLUTION OF 500MB CLOSED LOW AT 12 FRI CENTERED OVER THE WESTERN THIRD OF ND. THE HIGHEST UNCERTAINTY LIES WITHIN THE POSITION OF THE WARM FRONT AND WHERE IT STALLS. THE 00Z ECMWF AND GEM CONTINUE TO STALL IT NORTH OF THE CWFA WHEREAS THE GFS STALLS IT ACROSS THE NORTHERN PORTIONS OF THE FA. IF THE GFS IS RIGHT MUCH HIGHER AMOUNTS OF QPF ARE POSSIBLE. THE DRIER SOLNS WOULD BRING THE DRY SLOT ACROSS THE CWFA ON FRIDAY. ALL SOLNS BRING DEFORMATION RAIN BANDS THROUGH THE AREA ON SATURDAY...GFS FASTER TO EXIT SAT AFTERNOON. SUNDAY AND MONDAY 500MB RIDGING AND SFC HIGH PRESSURE WILL GIVE QUITE WEATHER TO THE AREA WITH SEASONAL TEMPERATURES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 110 PM CDT TUE MAY 28 2013 CIGS/VSBY A CHALLENGE AS AN AREA OF LOW PRESSURE IS SITUATED IN NC NORTH DAKOTA WITH AN ATTENDANT TROF EXTENDING SOUTH NEAR JMS. OBSERVATIONS SHOW MAINLY MVFR/IFR CIGS OVER THE AREA...BUT VIS SATELLITE SHOWS MORE CELLULAR DEVELOPMENT AND SCATTERING SKIES WITH INCREASED HEATING. EXPECT SCATTERING OF CLOUDS TO CONTINUE ALONG WITH INCREASING CLOUD/CIG HEIGHTS INTO THE AFTERNOON AND REFLECTED SAME IN THE TAFS. A BIT OF DRYING CAN BE EXPECTED IN THE LOWER LEVELS AS INDICATED BY FORECAST SOUNDINGS AND LOOK FOR THAT TO EXPAND EAST ACROSS ND INTO MN THRU THE AFTERNOON AND EVENING HOURS. OTHERWISE...EXPECT CIGS TO REMAIN OVERNIGHT THRU THE REST OF THE PERIOD...BUT LOOKING FOR MAINLY VFR CONDITIONS WITH POCKETS OF MVFR CIGS. && .HYDROLOGY... ISSUED AT 110 PM CDT TUE MAY 28 2013 THE AREAL FLOOD WARNING FOR PEMBINA...WALSH...AND EASTERN CAVALIER COUNTIES HAS BEEN CANCELLED. ALTHOUGH THE GROUND REMAINS SATURATED AND MANY AREA RIVERS AND STREAMS REMAIN HIGH...OVERLAND FLOOD CONCERNS HAVE DIMINISHED SIGNIFICANTLY OVER THE PAST FEW DAYS. OTHERWISE...MOST RIVERS OVER THE REGION HAVE CONTINUED TO GRADUALLY RECEDE OR ARE HOLDING NEARLY STEADY...WITH NO FORECAST POINTS CURRENTLY ABOVE FLOOD STAGE. THE POTENTIAL EXISTS FOR LOCALLY HEAVY RAINFALL WEDNESDAY EVENING INTO EARLY THURSDAY MORNING...MAINLY ACROSS EASTERN NORTH DAKOTA. THE MOST PROBABLE SCENARIO GIVES WIDESPREAD RAINFALL OF 0.50 TO 1.50 INCHES DURING THIS PERIOD. THESE AMOUNTS WOULD HAVE MINIMAL IMPACTS. HOWEVER...ISOLATED AMOUNTS OF 2 OR MORE INCHES ARE POSSIBLE...AND COULD HAVE IMPACTS DEPENDING ON HOW MUCH AND WHERE IT FALLS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...ROGERS SHORT TERM...TG LONG TERM...TG/JK AVIATION...HOPKINS HYDROLOGY...MAKOWSKI
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1004 AM CDT TUE MAY 28 2013 .UPDATE... ISSUED AT 1004 AM CDT TUE MAY 28 2013 15 UTC REGIONAL RADAR SHOWS A NARROW BAND OF LIGHT SHOWERS ACROSS NORTHEAST ND...MOVING INTO CANADA AROUND 20 MPH. ANY ADDITIONAL ISOLATED TO SCATTERED SHOWERS THROUGH THE DAY WILL BE CONFINED MAINLY TO EASTERN ND AS DEPICTED BY THE LATEST SUITE OF MODELS. SHOULD SEE SOME BREAKS IN THE CLOUDS ALONG AND WEST OF THE VALLEY LATE THIS MORNING AND THROUGH THE AFTERNOON...BUT OVERCAST SKIES EXPECTED TO PERSIST ACROSS MUCH OF NORTHWEST AND WEST CENTRAL MN THROUGH THE DAY. AS A RESULT...DID DROP TEMPERATURES A FEW DEGREES ACROSS WEST CENTRAL MN WITH HIGHS IN THE MID TO UPPER 60S. ALL OTHER AREAS SHOULD SEE ENOUGH SUN TO CLIMB INTO THE LOWER 70S. MODEST SOUTHERLY WIND WILL GRADUALLY WEAKEN AND SHIFT TO THE WEST THIS EVENING AND OVERNIGHT AS THE MAIN SURFACE TROUGH MOVES ACROSS THE REGION. OVERALL...FORECAST IS IN GOOD SHAPE WITH NO MAJOR CHANGES AT THIS TIME. UPDATE ISSUED AT 638 AM CDT TUE MAY 28 2013 SHORTWAVE TROUGH IS SWINGING THROUGH THE FA AND ASSOCIATED FORCING IS CAUSING SHOWERS TO DEVELOP WITHIN THE DEVILS LAKE BASIN. EXPECT THIS ACTIVITY TO PROPAGATE TO THE NORTHEAST ALONG WITH THE UPPER WAVE. INCREASED POPS TO HIGH CHANCE CATEGORY FOR THIS ACTIVITY. STILL EXPECT SOME CLEARING ACROSS THE WESTERN FA BY THIS AFTERNOON. THIS SHOULD ALLOW ENOUGH HEATING TO COMBINE WITH UPPER JET STREAK FOR ISOLATED SHOWERS...WHICH THE HRRR CONTINUES TO INDICATE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 347 AM CDT TUE MAY 28 2013 THERE ARE A COUPLE UPPER LEVEL SHORTWAVES ACROSS EASTERN AND NORTHERN NORTH DAKOTA THAT WILL CONTINUE TO PROPAGATE TO THE NORTHEAST TODAY. WILL KEEP THE ISOLD-SCATTERED SHOWERS THROUGH THE MORNING HOURS ACROSS THE NE FA. HRRR/RAP/4-KM WRF MODELS INDICATE THE POTENTIAL FOR ISOLD SHOWERS ALONG AND WEST OF THE VALLEY THIS AFTERNOON AS HEATING COMBINES WITH AN UPPER LEVEL JET STREAK. OTHERWISE...THIS PERIOD WILL BE MOSTLY DRY AS RIDGING AFFECTS THE AREA TONIGHT INTO TUESDAY AND MUCH OF WEDNESDAY. THUNDER CHANCES INCREASE BY LATER WEDNESDAY AFTERNOON ACROSS THE SOUTHERN FA. TEMPERATURES SHOULD BE NEAR NORMAL VALUES AS CLOUD COVER IS EXPECTED TO BE MORE SCATTERED THAN THE PAST COUPLE DAYS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 347 AM CDT TUE MAY 28 2013 WEDNESDAY NIGHT-THURSDAY NIGHT... SEVERE POTENTIAL AND HEAVY RAIN POTENTIAL WILL BE THE MAIN CONCERNS. ALTHOUGH MODELS HAVE HAVE A SIMILAR IDEA...THERE ARE DIFFERENCES WITH THE LEAD SHORTWAVE AND POTENTIAL IMPACTS WEDNESDAY EVENING INTO THURSDAY MORNING. ECMWF IS THE PREFERRED MODEL AS PER THE PMDHMD. FOR WED NIGHT...THERE WILL LIKELY BE A SURGE OF INSTABILITY AS AN ELEVATED WARM FRONT PROPAGATES NORTHWARD THROUGH THE FA. SEVERE POTENTIAL WILL DEPEND ON THE STRENGTH OF THE LOW LEVEL JET...THE ECMWF IS AROUND 40 KNOTS. DEEP LAYER SHEAR AND INSTABILITY WILL BE MARGINAL...AND CAN IMAGINE A FEW SEVERE STORMS...BUT NOT AN OUTBREAK SCENARIO. SHOWER AND THUNDERSTORM CHANCES CONTINUE INTO THURSDAY AS THE REGION REMAINS IN WARM AIR ADVECTION REGIME. THESE CHANCES END FROM WEST TO EAST THURSDAY AFTERNOON AND EVENING AS A COLD FRONT AND STABLE AIRMASS MOVE INTO THE REGION. IT IS BECOMING MORE LIKELY THAT THE UPPER LOW WILL CLOSE OFF WITHIN NORTH DAKOTA...WITH THE BOUNDARY STALLING NORTH OF THE INTERNATIONAL BORDER. THE MAIN HEAVY RAIN THREAT WILL BE WHERE EVER THIS BOUNDARY STALLS. HOWEVER...PWATS WILL INCREASE TO AROUND 1.5 INCHES WED NIGHT...AND THE POTENTIAL WILL EXIST FOR ISOLATED HEAVY RAINFALL. THIS POTENTIAL WILL BE GREATEST WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED (NOSE OF LOW LEVEL JET)...AND WILL MENTION LOCALLY HEAVY RAINFALL POSSIBLE FOR AREAS WEST OF THE VALLEY. FRIDAY-MONDAY... MODELS IN GOOD AGREEMENT WITH PLACEMENT AND EVOLUTION OF 500MB CLOSED LOW AT 12 FRI CENTERED OVER THE WESTERN THIRD OF ND. THE HIGHEST UNCERTAINTY LIES WITHIN THE POSITION OF THE WARM FRONT AND WHERE IT STALLS. THE 00Z ECMWF AND GEM CONTINUE TO STALL IT NORTH OF THE CWFA WHEREAS THE GFS STALLS IT ACROSS THE NORTHERN PORTIONS OF THE FA. IF THE GFS IS RIGHT MUCH HIGHER AMOUNTS OF QPF ARE POSSIBLE. THE DRIER SOLNS WOULD BRING THE DRY SLOT ACROSS THE CWFA ON FRIDAY. ALL SOLNS BRING DEFORMATION RAIN BANDS THROUGH THE AREA ON SATURDAY...GFS FASTER TO EXIT SAT AFTERNOON. SUNDAY AND MONDAY 500MB RIDGING AND SFC HIGH PRESSURE WILL GIVE QUITE WEATHER TO THE AREA WITH SEASONAL TEMPERATURES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 638 AM CDT TUE MAY 28 2013 BAND OF IFR/MVFR CIGS WILL REMAIN THROUGH MUCH OF THE MORNING HOURS AND GRADUALLY SCATTER AND/OR CLEAR FROM THE WEST FOR THE AFTERNOON HOURS. && .HYDROLOGY... ISSUED AT 347 AM CDT TUE MAY 28 2013 AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR PEMBINA...WALSH... AND EASTERN CAVALIER COUNTIES THROUGH TODAY. THE POTENTIAL EXISTS FOR LOCALLY HEAVY RAINFALL WEDNESDAY EVENING INTO EARLY THURSDAY MORNING...MAINLY ACROSS EASTERN NORTH DAKOTA. THE MOST PROBABLE SCENARIO GIVES WIDESPREAD RAINFALL OF 0.50 TO 1.50 INCHES DURING THIS PERIOD. THESE AMOUNTS WOULD HAVE MINIMAL IMPACTS. HOWEVER...ISOLATED AMOUNTS OF 2 OR MORE INCHES ARE POSSIBLE...AND COULD HAVE IMPACTS DEPENDING ON HOW MUCH AND WHERE IT FALLS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...ROGERS SHORT TERM...TG LONG TERM...TG/JK AVIATION...TG HYDROLOGY...MAKOWSKI/TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
638 AM CDT TUE MAY 28 2013 .UPDATE... ISSUED AT 638 AM CDT TUE MAY 28 2013 SHORTWAVE TROUGH IS SWINGING THROUGH THE FA AND ASSOCIATED FORCING IS CAUSING SHOWERS TO DEVELOP WITHIN THE DEVILS LAKE BASIN. EXPECT THIS ACTIVITY TO PROPAGATE TO THE NORTHEAST ALONG WITH THE UPPER WAVE. INCREASED POPS TO HIGH CHANCE CATEGORY FOR THIS ACTIVITY. STILL EXPECT SOME CLEARING ACROSS THE WESTERN FA BY THIS AFTERNOON. THIS SHOULD ALLOW ENOUGH HEATING TO COMBINE WITH UPPER JET STREAK FOR ISOLATED SHOWERS...WHICH THE HRRR CONTINUES TO INDICATE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 347 AM CDT TUE MAY 28 2013 THERE ARE A COUPLE UPPER LEVEL SHORTWAVES ACROSS EASTERN AND NORTHERN NORTH DAKOTA THAT WILL CONTINUE TO PROPAGATE TO THE NORTHEAST TODAY. WILL KEEP THE ISOLD-SCATTERED SHOWERS THROUGH THE MORNING HOURS ACROSS THE NE FA. HRRR/RAP/4-KM WRF MODELS INDICATE THE POTENTIAL FOR ISOLD SHOWERS ALONG AND WEST OF THE VALLEY THIS AFTERNOON AS HEATING COMBINES WITH AN UPPER LEVEL JET STREAK. OTHERWISE...THIS PERIOD WILL BE MOSTLY DRY AS RIDGING AFFECTS THE AREA TONIGHT INTO TUESDAY AND MUCH OF WEDNESDAY. THUNDER CHANCES INCREASE BY LATER WEDNESDAY AFTERNOON ACROSS THE SOUTHERN FA. TEMPERATURES SHOULD BE NEAR NORMAL VALUES AS CLOUD COVER IS EXPECTED TO BE MORE SCATTERED THAN THE PAST COUPLE DAYS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 347 AM CDT TUE MAY 28 2013 WEDNESDAY NIGHT-THURSDAY NIGHT... SEVERE POTENTIAL AND HEAVY RAIN POTENTIAL WILL BE THE MAIN CONCERNS. ALTHOUGH MODELS HAVE HAVE A SIMILAR IDEA...THERE ARE DIFFERENCES WITH THE LEAD SHORTWAVE AND POTENTIAL IMPACTS WEDNESDAY EVENING INTO THURSDAY MORNING. ECMWF IS THE PREFERRED MODEL AS PER THE PMDHMD. FOR WED NIGHT...THERE WILL LIKELY BE A SURGE OF INSTABILITY AS AN ELEVATED WARM FRONT PROPAGATES NORTHWARD THROUGH THE FA. SEVERE POTENTIAL WILL DEPEND ON THE STRENGTH OF THE LOW LEVEL JET...THE ECMWF IS AROUND 40 KNOTS. DEEP LAYER SHEAR AND INSTABILITY WILL BE MARGINAL...AND CAN IMAGINE A FEW SEVERE STORMS...BUT NOT AN OUTBREAK SCENARIO. SHOWER AND THUNDERSTORM CHANCES CONTINUE INTO THURSDAY AS THE REGION REMAINS IN WARM AIR ADVECTION REGIME. THESE CHANCES END FROM WEST TO EAST THURSDAY AFTERNOON AND EVENING AS A COLD FRONT AND STABLE AIRMASS MOVE INTO THE REGION. IT IS BECOMING MORE LIKELY THAT THE UPPER LOW WILL CLOSE OFF WITHIN NORTH DAKOTA...WITH THE BOUNDARY STALLING NORTH OF THE INTERNATIONAL BORDER. THE MAIN HEAVY RAIN THREAT WILL BE WHERE EVER THIS BOUNDARY STALLS. HOWEVER...PWATS WILL INCREASE TO AROUND 1.5 INCHES WED NIGHT...AND THE POTENTIAL WILL EXIST FOR ISOLATED HEAVY RAINFALL. THIS POTENTIAL WILL BE GREATEST WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED (NOSE OF LOW LEVEL JET)...AND WILL MENTION LOCALLY HEAVY RAINFALL POSSIBLE FOR AREAS WEST OF THE VALLEY. FRIDAY-MONDAY... MODELS IN GOOD AGREEMENT WITH PLACEMENT AND EVOLUTION OF 500MB CLOSED LOW AT 12 FRI CENTERED OVER THE WESTERN THIRD OF ND. THE HIGHEST UNCERTAINTY LIES WITHIN THE POSITION OF THE WARM FRONT AND WHERE IT STALLS. THE 00Z ECMWF AND GEM CONTINUE TO STALL IT NORTH OF THE CWFA WHEREAS THE GFS STALLS IT ACROSS THE NORTHERN PORTIONS OF THE FA. IF THE GFS IS RIGHT MUCH HIGHER AMOUNTS OF QPF ARE POSSIBLE. THE DRIER SOLNS WOULD BRING THE DRY SLOT ACROSS THE CWFA ON FRIDAY. ALL SOLNS BRING DEFORMATION RAIN BANDS THROUGH THE AREA ON SATURDAY...GFS FASTER TO EXIT SAT AFTERNOON. SUNDAY AND MONDAY 500MB RIDGING AND SFC HIGH PRESSURE WILL GIVE QUITE WEATHER TO THE AREA WITH SEASONAL TEMPERATURES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 638 AM CDT TUE MAY 28 2013 BAND OF IFR/MVFR CIGS WILL REMAIN THROUGH MUCH OF THE MORNING HOURS AND GRADUALLY SCATTER AND/OR CLEAR FROM THE WEST FOR THE AFTERNOON HOURS. && .HYDROLOGY... ISSUED AT 347 AM CDT TUE MAY 28 2013 AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR PEMBINA...WALSH...AND EASTERN CAVALIER COUNTIES THROUGH TODAY. THE POTENTIAL EXISTS FOR LOCALLY HEAVY RAINFALL WEDNESDAY EVENING INTO EARLY THURSDAY MORNING...MAINLY ACROSS EASTERN NORTH DAKOTA. THE MOST PROBABLE SCENARIO GIVES WIDESPREAD RAINFALL OF 0.50 TO 1.50 INCHES DURING THIS PERIOD. THESE AMOUNTS WOULD HAVE MINIMAL IMPACTS. HOWEVER...ISOLATED AMOUNTS OF 2 OR MORE INCHES ARE POSSIBLE...AND COULD HAVE IMPACTS DEPENDING ON HOW MUCH AND WHERE IT FALLS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...TG LONG TERM...TG/JK AVIATION...TG HYDROLOGY...MAKOWSKI/TG
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
704 PM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL CONTINUE TO MOVE NORTH OF THE AREA THROUGH TONIGHT. BY LATE WEDNESDAY THE FRONT WILL HAVE PUSHED WAY NORTH OF THE AREA AND TEMPERATURES WILL BE WELL ABOVE NORMAL. A COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE FORECAST AREA SUNDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... THE QUESTION IS STILL HOW MUCH CONVECTION WILL OCCUR THIS EVENING AND TONIGHT. WE HAVE REACHED THE CONVECTIVE TEMPERATURES. THE AIRMASS IS UNSTABLE AND MOIST BUT COULD BE MORE UNSTABLE. SOME OF THE BETTER DYNAMICS ARE TO THE NORTH IN MICHIGAN. WENT MAINLY CHANCE POPS. ACCORDING TO THE HRRR MODEL AND THE 4KM WRF NMM MODEL ANOTHER WAVE WILL HIT THE AREA AFTER DARK. ON THE EDGE ABOUT THAT. WENT ON THE WARM SIDE WITH THE LOWS BECAUSE OF THE MODERATELY HIGH DEW POINTS. THREAT FOR SEVERE CONTINUES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/... WEDNESDAY IS TOUGH...SOME CONVECTION WILL BE IN THE AREA IN THE MORNING BUT NOT SURE ABOUT THE AFTERNOON. KEPT THE CHANCE GOING. DRY AND MUGGY WEDNESDAY NIGHT. THE MODELS ARE TRYING TO HINT AT SOME CONVECTIVE ACTIVITY THURSDAY AFTERNOON. IT MAY JUST BE ISOLATED SO LEFT IT OUT FOR THE MOMENT. INCLUDED A CHANCE STARTING FRIDAY INTO FRIDAY NIGHT AS THE AIRMASS BECOMES MORE UNSTABLE. USED A BLEND OF GUIDANCE FOR THE LOWS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... MODELS IN REASONABLY GOOD AGREEMENT WITH THE NEXT FRONT MOVING THROUGH EARLY SUNDAY...AFTER THAT THE MODELS DIVERGE. THE ECMWF PUSHES THE FRONT SOUTH OF THE AREA BY SUNDAY EVENING TAKING THE RAIN WITH IT. THE GFS ON THE OTHER HAND STALLS THE FRONT ACROSS THE AREA AS A SECONDARY WAVE DEVELOPS AND MOVES ACROSS THE AREA SUNDAY NIGHT INTO MONDAY. FOR NOW WITH SO MUCH UNCERTAINTY LEFT LIKELY POPS SATURDAY NIGHT INTO SUNDAY WITH JUST LOW CHANCE POPS SUNDAY NIGHT AND MONDAY. BOTH MODELS PUSH CANADIAN HIGH PRESSURE SOUTH OVER THE AREA BY TUESDAY SO SHOULD BE DRY AND COOLER. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... WARM AND UNSTABLE AIRMASS SOUTH OF THE WARM FRONT WILL PERSIST THRU THE TAF PERIOD BUT FOCUS FOR CONVECTIVE DEVELOPMENT LACKING. WIDELY SCT TSRA WILL BE POSSIBLE...ESPECIALLY THE REST OF THIS EVENING AND AGAIN WED AFTERNOON. ONLY TAF SITE WITH DECENT THREAT FOR TSRA NEXT FEW HOURS APPEARS TO BE ERI. SOME FOG MAY DEVELOP TONIGHT BUT SURFACE WINDS SHOULD TEND TO STAY 8 KNOTS OR MORE SO DON`T THINK FOG WILL BECOME TOO MUCH OF A PROBLEM...MAYBE SOME LOCAL MVFR AT THE FAVORED INLAND LOCATIONS. SW SURFACE WINDS WILL LIKELY INCREASE TO BE GUSTING 22 TO 25 KNOTS BY MIDDAY WED. .OUTLOOK...NON VFR POSSIBLE ON SATURDAY IN SHOWERS/THUNDERSTORMS. && .MARINE... A WARM FRONT STRETCHED ACROSS LAKE ERIE WILL PUSH NORTH OF THE LAKE TONIGHT. CONVECTION LIKELY THIS EVENING INTO THE OVERNIGHT HOURS SOME OF THE STORMS COULD BE STRONG TO SEVERE. AS THE FRONT LIFTS NORTH OF THE LAKE A SOUTH TO SOUTHWEST FLOW WILL DEVELOP OVER THE LAKE AND CONTINUE THROUGH THE END OF THE PERIOD. WITH A HOT AND MUGGY AIRMASS OVER A MUCH COOLER LAKE WILL BE HARD FOR WINDS TO MIX DOWN TO THE LAKE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...ADAMS MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
351 PM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT WILL CONTINUE TO MOVE NORTH OF THE AREA THROUGH TONIGHT. BY LATE WEDNESDAY THE FRONT WILL HAVE PUSHED WAY NORTH OF THE AREA AND TEMPERATURES WILL BE WELL ABOVE NORMAL. A COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE FORECAST AREA SUNDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... THE QUESTION IS STILL HOW MUCH CONVECTION WILL OCCUR THIS EVENING AND TONIGHT. WE HAVE REACHED THE CONVECTIVE TEMPERATURES. THE AIRMASS IS UNSTABLE AND MOIST BUT COULD BE MORE UNSTABLE. SOME OF THE BETTER DYNAMICS ARE TO THE NORTH IN MICHIGAN. WENT MAINLY CHANCE POPS. ACCORDING TO THE HRRR MODEL AND THE 4KM WRF NMM MODEL ANOTHER WAVE WILL HIT THE AREA AFTER DARK. ON THE EDGE ABOUT THAT. WENT ON THE WARMSIDE WITH THE LOWS BECAUSE OF THE MODERATELY HIGH DEW POINTS. THREAT FOR SEVERE CONTINUES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/... WEDNESDAY IS TOUGH...SOME CONVECTION WILL BE IN THE AREA IN THE MORNING BUT NOT SURE ABOUT THE AFTERNOON. KEPT THE CHANCE GOING. DRY AND MUGGY WEDNESDAY NIGHT. THE MODELS ARE TRYING TO HINT AT SOME CONVECTIVE ACTIVITY THURSDAY AFTERNOON. IT MAY JUST BE ISOLATED SO LEFT IT OUT FOR THE MOMENT. INCLUDED A CHANCE STARTING FRIDAY INTO FRIDAY NIGHT AS THE AIRMASS BECOMES MORE UNSTABLE. USED A BLEND OF GUIDANCE FOR THE LOWS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... MODELS IN REASONABLY GOOD AGREEMENT WITH THE NEXT FRONT MOVING THROUGH EARLY SUNDAY...AFTER THAT THE MODELS DIVERGE. THE ECMWF PUSHES THE FRONT SOUTH OF THE AREA BY SUNDAY EVENING TAKING THE RAIN WITH IT. THE GFS ON THE OTHER HAND STALLS THE FRONT ACROSS THE AREA AS A SECONDARY WAVE DEVELOPS AND MOVES ACROSS THE AREA SUNDAY NIGHT INTO MONDAY. FOR NOW WITH SO MUCH UNCERTAINTY LEFT LIKELY POPS SATURDAY NIGHT INTO SUNDAY WITH JUST LOW CHANCE POPS SUNDAY NIGHT AND MONDAY. BOTH MODELS PUSH CANADIAN HIGH PRESSURE SOUTH OVER THE AREA BY TUESDAY SO SHOULD BE DRY AND COOLER. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... WARM FRONT CURRENTLY NEAR A DTW TO ERI TO PIT LINE. WARM UNSTABLE AIRMASS HAS SPREAD ACROSS THE AREA. CAPES HAVE RISEN TO 2500 J/KG IN THE WEST TO AROUND 1000 J/KG ELSEWHERE...EXPECT CAPES TO RISE TO BETWEEN 2000-4000 J/KG BY LATE AFTERNOON. CLOUDS FROM MORNING SHOWERS HAVE HELPED INSULATE AREA FROM TSRA FOR NOW. EXPECT TSRA TO BUILD SW FROM SE LOWER MICHIGAN AND MOVE ACROSS THE AREA THIS AFTERNOON AND EVENING. SPC HAS AREA IN SLIGHT RISK COULD SEE ISOLATED SEVERE TSRA WIND GUSTS...BUT DO NOT NOT EXPECT WIDESPREAD OUTBREAK. SECOND WAVE IS POSSIBLE OVERNIGHT AS TSRA DEVELOP FROM ILLINOIS TO OKLAHOMA. MODELS NOT IN GOOD AGREEMENT ON TIMING OF THE TSRA...SO USED TEMPOS IN TAFS TO GIVE WINDOW OF BEST OPPORTUNITY. .OUTLOOK...NON VFR POSSIBLE ON SATURDAY IN SHOWERS/THUNDERSTORMS. && .MARINE... ... A WARM FRONT STRETCHED ACROSS LAKE ERIE WILL PUSH NORTH OF THE LAKE TONIGHT. CONVECTION LIKELY THIS EVENING INTO THE OVERNIGHT HOURS SOME OF THE STORMS COULD BE STRONG TO SEVERE. AS THE FRONT LIFTS NORTH OF THE LAKE A SOUTH TO SOUTHWEST FLOW WILL DEVELOP OVER THE LAKE AND CONTINUE THROUGH THE END OF THE PERIOD. WITH A HOT AND MUGGY AIRMASS OVER A MUCH COOLER LAKE WILL BE HARD FOR WINDS TO MIX DOWN TO THE LAKE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...DJB MARINE...DJB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
220 PM EDT TUE MAY 28 2013 .SYNOPSIS... WARM FRONT EXITING NORTHERN COUNTIES EARLY THIS MORNING. INCREASING HEAT/HUMIDITY THIS AFTERNOON TO END OF THE WEEK. NO ORGANIZED FRONTS IN VICINITY UNTIL WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 1030 AM UPDATE...INGESTED RECENT OBS. OVERALL FCST GENERALLY ON TRACK. TWEAKED POPS AND SKY JUST A BIT TO REFLECT CURRENT RADAR TRENDS...INCLUDING LOWERING POPS TO SLIGHT CHANCE ACROSS NE ZONES AND INCREASING POPS A TAD WITH THIN BAND OF LIGHT SHOWERS NEAR THE OHIO RIVER. AT 10Z ON THE GRAVEYARD SHIFT...SHALLOW SURFACE WARM FRONT NOW NORTH OF AREA. A MID LEVEL 700 MB TROF AXIS WAS DEPICTED ON RAP AND VAD WINDS NR ILN TO SDF AT 08Z...THEN CMH TO LEX AT 10Z. WEAK SUPPORT ASSOCIATED WITH THAT FEATURE CROSSES OUR NORTHERN ZONES 12Z THRU 15Z. SO HAVE SOME 20 TO 30 POPS ACROSS THE NORTH THIS MORNING FOR A LIGHT SHOWER. YET...RAP FORECASTING SOUTHERN EXTENSION OF THAT VORT AXIS DRAGGING THROUGH DURING THE LATE AFTERNOON. BOTH NAM AND GFS ON THEIR 00Z RUNS...SHOW MID LEVEL WARMING AT AROUND 8 TO 10 THSD FT TRYING TO FORM A CAP. SO WILL ONLY LEAVE SOME 20/30 POPS FOR THE POSSIBILITY OF A DIURNAL DRIVEN INSTABILITY SHOWER OR THUNDERSTORM TO FORM THIS AFTERNOON...MAINLY EAST AND SOUTH OF OHIO RIVER. THE WARM UP STARTS IN EARNEST TODAY. OVERALL NO BIG CHANGES TO OUR TEMPERATURE FORECAST. MARGINAL 850 MB MOISTURE LINGERS OVERNIGHT...SO PATCHES OF 4 TO 7 THSD FT CLOUDS MAY STILL BE HANGING AROUND LATE TONIGHT. OF COURSE...THIS CAUSES US HEADACHES TRYING TO FIGURE THE MINIMUM TEMPERATURE TONIGHT. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... UPPER RIDGE CONTINUES TO BUILD THROUGH THURSDAY AFTERNOON. TEMPERATURES WILL TOP OUT THURSDAY AFTERNOON WITH THE WARMEST READINGS SO FAR THIS YEAR. USED A MAV/MET BLEND FOR WEDNESDAY AND THURSDAY...WHICH BUMPED UP AFTERNOON HIGHS JUST A BIT EACH DAY. THE RIDGE STARTS BREAKING DOWN BY FRIDAY AS AN UPPER TROUGH BEGINS TO DROP INTO THE UPPER PLAINS. PRECIP WISE...HAVE DIURNAL SHOWERS AND STORMS IN THE WV MOUNTAINS EACH AFTERNOON DUE TO ELEVATED HEAT SOURCE INSTABILITY...AND ALSO INCLUDED SOME AFTERNOON CONVECTION IN SE OHIO FRIDAY AFTERNOON AS TEMPS ALOFT COOL A BIT AND A 500MB RIPPLE STREAMS ACROSS OHIO. && .LONG TERM /SATURDAY THROUGH MONDAY/... GFS/ECMWF BEGIN TO DIVERGE BY THE WEEKEND WITH THE POSITION OF THE COLD FRONT ASSOCIATED WITH OUR NEXT SYSTEM...GFS BREAKS THE RIDGE DOWN FASTER ALLOWING THE COLD FRONT TO ENTER OUR WESTERN COUNTIES EARLY SATURDAY WHILE THE ECMWF CONTINUES TO AMPLIFY THE RIDGE OVER THE SE STATES THROUGH SATURDAY NOT ALLOWING FOR FROPA ACROSS OUR CWA UNTIL LATER IN THE DAY SUNDAY...GIVEN THE MORE LINEAR SOLUTION OF THE GFS AND EXPECTED INFLUENCE OF CONVECTIVE PROCESSES ASSOCIATED WITH THE FRONT WILL PUT MORE WEIGHT ON ECMWF TIMING...ZONAL FLOW APPEARS TO MOVE IN BEHIND THE TROUGH OUT TO DAY 6 AND 7. && .AVIATION /18Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS WILL PREVAIL THROUGH THE VALID PERIOD. SCATTERED CEILINGS AROUND 6KFT TO 8KFT WILL CONTINUE HOWEVER THIS AFTERNOON AND OVERNIGHT...WITH THE POSSIBILITY OF A BRIEF SHOWER OR EVEN AN ISOLATED THUNDERSTORM MAINLY ACROSS SE OHIO OR NE WEST VIRGINIA. WIND SPEEDS WILL REMAIN A BIT GUSTY THIS AFTERNOON BUT SUBSIDE BY ABOUT 00Z. OVERNIGHT A FEW TO SCATTERED MID LEVEL DECK SHOULD PERSIST WITH ANY PRECIP ENDING BY 03Z. DECENT BOUNDARY LAYER WINDS WITH THE CLOUDS SHOULD PRECLUDE WIDESPREAD DENSE FOG AND LOW STRATUS DEVELOPMENT OVERNIGHT...THOUGH SOME PATCHY MVFR VIS IS POSSIBLE AT THE USUAL SPOTS SUCH AS EKN. FEW TO SCATTERED MID-LEVEL CLOUDS WILL CONTINUE WED MORNING AS WELL...WITH MORE BREAKS EXPECTED. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: COVERAGE OF PRECIP MAY VARY SLIGHTLY. REDUCED VISIBILITY DURING THE OVERNIGHT HOURS MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z WEDNESDAY... NO WIDESPREAD IFR EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB/50 SHORT TERM...MZ LONG TERM...JM AVIATION...50
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1039 AM EDT TUE MAY 28 2013 .SYNOPSIS... WARM FRONT EXITING NORTHERN COUNTIES EARLY THIS MORNING. INCREASING HEAT/HUMIDITY THIS AFTERNOON TO END OF THE WEEK. NO ORGANIZED FRONTS IN VICINITY UNTIL WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 1030 AM UPDATE...INGESTED RECENT OBS. OVERALL FCST GENERALLY ON TRACK. TWEAKED POPS AND SKY JUST A BIT TO REFLECT CURRENT RADAR TRENDS...INCLUDING LOWERING POPS TO SLIGHT CHANCE ACROSS NE ZONES AND INCREASING POPS A TAD WITH THIN BAND OF LIGHT SHOWERS NEAR THE OHIO RIVER. AT 10Z ON THE GRAVEYARD SHIFT...SHALLOW SURFACE WARM FRONT NOW NORTH OF AREA. A MID LEVEL 700 MB TROF AXIS WAS DEPICTED ON RAP AND VAD WINDS NR ILN TO SDF AT 08Z...THEN CMH TO LEX AT 10Z. WEAK SUPPORT ASSOCIATED WITH THAT FEATURE CROSSES OUR NORTHERN ZONES 12Z THRU 15Z. SO HAVE SOME 20 TO 30 POPS ACROSS THE NORTH THIS MORNING FOR A LIGHT SHOWER. YET...RAP FORECASTING SOUTHERN EXTENSION OF THAT VORT AXIS DRAGGING THROUGH DURING THE LATE AFTERNOON. BOTH NAM AND GFS ON THEIR 00Z RUNS...SHOW MID LEVEL WARMING AT AROUND 8 TO 10 THSD FT TRYING TO FORM A CAP. SO WILL ONLY LEAVE SOME 20/30 POPS FOR THE POSSIBILITY OF A DIURNAL DRIVEN INSTABILITY SHOWER OR THUNDERSTORM TO FORM THIS AFTERNOON...MAINLY EAST AND SOUTH OF OHIO RIVER. THE WARM UP STARTS IN EARNEST TODAY. OVERALL NO BIG CHANGES TO OUR TEMPERATURE FORECAST. MARGINAL 850 MB MOISTURE LINGERS OVERNIGHT...SO PATCHES OF 4 TO 7 THSD FT CLOUDS MAY STILL BE HANGING AROUND LATE TONIGHT. OF COURSE...THIS CAUSES US HEADACHES TRYING TO FIGURE THE MINIMUM TEMPERATURE TONIGHT. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... UPPER RIDGE CONTINUES TO BUILD THROUGH THURSDAY AFTERNOON. TEMPERATURES WILL TOP OUT THURSDAY AFTERNOON WITH THE WARMEST READINGS SO FAR THIS YEAR. USED A MAV/MET BLEND FOR WEDNESDAY AND THURSDAY...WHICH BUMPED UP AFTERNOON HIGHS JUST A BIT EACH DAY. THE RIDGE STARTS BREAKING DOWN BY FRIDAY AS AN UPPER TROUGH BEGINS TO DROP INTO THE UPPER PLAINS. PRECIP WISE...HAVE DIURNAL SHOWERS AND STORMS IN THE WV MOUNTAINS EACH AFTERNOON DUE TO ELEVATED HEAT SOURCE INSTABILITY...AND ALSO INCLUDED SOME AFTERNOON CONVECTION IN SE OHIO FRIDAY AFTERNOON AS TEMPS ALOFT COOL A BIT AND A 500MB RIPPLE STREAMS ACROSS OHIO. && .LONG TERM /SATURDAY THROUGH MONDAY/... GFS/ECMWF BEGIN TO DIVERGE BY THE WEEKEND WITH THE POSITION OF THE COLD FRONT ASSOCIATED WITH OUR NEXT SYSTEM...GFS BREAKS THE RIDGE DOWN FASTER ALLOWING THE COLD FRONT TO ENTER OUR WESTERN COUNTIES EARLY SATURDAY WHILE THE ECMWF CONTINUES TO AMPLIFY THE RIDGE OVER THE SE STATES THROUGH SATURDAY NOT ALLOWING FOR FROPA ACROSS OUR CWA UNTIL LATER IN THE DAY SUNDAY...GIVEN THE MORE LINEAR SOLUTION OF THE GFS AND EXPECTED INFLUENCE OF CONVECTIVE PROCESSES ASSOCIATED WITH THE FRONT WILL PUT MORE WEIGHT ON ECMWF TIMING...ZONAL FLOW APPEARS TO MOVE IN BEHIND THE TROUGH OUT TO DAY 6 AND 7. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... PATCHY CEILINGS AT 6 TO 8 THSD FT 15Z WITH ISOLATED TO SCATTERED LIGHT SHOWERS POSSIBLE...MAINLY ACROSS EASTERN OHIO AND NORTHERN HALF OF WEST VIRGINIA. VSBY MAY LOWER BRIEFLY TO 6 OR 5 MILES. SCATTERED TO BROKEN CLOUDS AT 4 TO 5 THSD FT AGL 14Z THROUGH 23Z WITH INCREASING SURFACE WINDS FROM THE SOUTHWEST. ISOLATED CONVECTION MAY FORM 18Z TODAY TO 00Z WEDNESDAY. 00Z NAM AND GFS TRY TO WARM HE MID LEVELS AT 8 TO 10 THSD FT MSL JUST ENOUGH TO FORM CAP. YET...A WEAK VORT MAX AT 500 MB AND INCREASING SURFACE HEATING...HAS US STILL MENTIONING THE POSSIBILITY OF ISOLATED CONVECTION. MARGINAL 850 MB MOISTURE LINGERS TONIGHT AS SURFACE WINDS DECREASE. SO PATCHES OF 4 TO 6 THSD FT AGL SCATTERED TO BROKEN CLOUDS WITH CIRRUS ABOVE. SOME 5 TO 6 MILES IN HAZE MAY FORM IN THE MOUNTAIN VALLEYS VCNTY EKN FOR THE 06Z TO 12Z WEDNESDAY TIME FRAME. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: ISOLATED AFTERNOON CONVECTION MAY NOT FORM WITH DEVELOPING MID LEVEL WARMING/CAP. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z WEDNESDAY... NO WIDESPREAD IFR EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB/50 SHORT TERM...MZ LONG TERM...JM AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1007 AM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT FROM THE MIDWEST TO THE OHIO VALLEY WILL SLOWLY PUSH NORTHEAST TODAY AND TONIGHT. THIS WILL PUT THE LOCAL AREA IN POSITION FOR SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS. BY LATE WEDNESDAY THE FRONT WILL HAVE PUSHED NORTH OF THE AREA AND TEMPERATURES WILL BE WELL ABOVE NORMAL. A COLD FRONT IS EXPECTED TO MOVE EAST ACROSS OHIO SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE BIG QUESTION IS HOW MUCH SHOWER AND THUNDERSTORM ACTIVITY WILL OCCUR THIS AFTERNOON. A WAVE IS MOVING THROUGH NOW AND THEN MORE SHOWERS AND THUNDERSTORMS WILL AFFECT EXTREME NW OH AND THE EASTERN COUNTIES THIS AFTERNOON. GOING WITH THE HRRR AND THE 4KM WRF NMM MODEL. WATCHING TO SEE HOW MUCH FILTERED SUNSHINE WE GET...THAT WILL BE KEY. NW OH IS GETTING SOME NOW BUT THAT SHOULD BE GOING AWAY BY NOON AND THE MORE SIGNIFICANT SUNSHINE MAY STAY SOUTH OF THE AREA. CONTINUED WITH SPC SLIGHT RISK OF SEVERE ACROSS THE ENTIRE FORECAST AREA. PREVIOUS DISCUSSION... ONE BATCH OF STEADY RAIN WILL BE PULLING OUT TO THE EAST EARLY THIS MORNING...BUT RIGHT ON ITS HEELS IS THE NEXT CLUSTER OF SHOWERS AND THUNDERSTORMS ACROSS NW OH...WITH ANOTHER UPSTREAM OF THAT. WITH A RELATIVELY FLAT RIDGE ACROSS THE OHIO VALLEY...WEAK DISTURBANCES IN THE FLOW WILL KEEP THE WARM FRONT ACTIVE FOR THE NEXT 24 TO 36 HOURS. BIG QUESTION TODAY WILL BE HOW WELL WILL WE DESTABILIZE. AS PER SPC DISCUSSION...REMNANT MCV FROM UPSTREAM CONVECTION/SHORTWAVE WILL BE THE KICKER FOR STORMS TODAY...SOME OF WHICH COULD BECOME STRONG TO SEVERE WITH WIND THE PRIMARY THREAT. THE RAINFALL WILL BE NEEDED AS WE ARE RUNNING 2 TO NEARLY 3 INCHES BELOW NORMAL SINCE MARCH 1ST. TEMPERATURES WILL BE AN IMPROVEMENT OVER YESTERDAY. WENT CLOSER TO GUIDANCE...BUT STUCK JUST A BIT COOLER. UPDATE INCLUDES TWEAKS TO VERY NEAR TERM PRECIP CHANCES...TIMING THE BATCH FROM NW OHIO IN TO THE AREA. PRECIP CHANCES END UP SOUNDING VAGUE WITH CHANCES FOR MUCH OF TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... IT WILL LIKELY TAKE UNTIL WEDNESDAY...POSSIBLY WEDNESDAY AFTERNOON BEFORE WARM FRONT LIFTS FAR ENOUGH NORTH TO CLEAR US FROM A THREAT OF SHOWERS AND THUNDERSTORMS. TIMING ANY OF THIS NEARLY IMPOSSIBLE YET. WILL CONTINUE THE BETTER CHANCES FOR SHOWERS/THUNDERSTORMS ACROSS THE NORTH TONIGHT AND THEN A FEW SCATTERED SHOWERS/THUNDERSTORMS FOR WEDNESDAY. RELATIVELY MILD NIGHTS COMING UP WITH LOWS IN THE 60S. HIGHS WILL INCH UP INTO THE 80S...WITH MID AND UPPER 80S FOR THURSDAY. RIDGE BEGINS TO SHIFT EAST FRIDAY AND WE MAY BE ABLE TO KNOCK A FEW DEGREES OFF HIGHS. MINIMAL CHANCES FOR SHOWERS AND THUNDERSTORMS RETURNING FRIDAY NIGHT FROM THE WEST AS ENERGY SHEARS OUT FROM THE CENTRAL PLAINS TROUGH TOWARD THE LOWER GREAT LAKES. GIVEN THE RELATIVELY DRY CONDITIONS OVER MOST OF THE PAST FEW WEEKS...DON`T SEE MUCH OF A FLOOD THREAT. HOWEVER...THE SITUATION MAY ALLOW FOR SOME REPEATED HEAVY RAINS IN SOME LOCATIONS SO THINGS COULD CHANGE LOCALLY. && .LONG TERM /SATURDAY THROUGH MONDAY/... THE NEXT COLD FRONT IS DUE ON SUNDAY. THERE IS SOME QUESTIONS AS TO HOW FAR AHEAD OF THE FRONT WE CAN GET THUNDERSTORMS. MOST OF THE MODELS HAVE BEEN POSTING QPF AND INDICATING SHOWERS AND STORMS ON SATURDAY. IT SHOULD BE WARM AND UNSTABLE AND WILL KEEP A CHANCE OF SHOWERS/STORMS IN THE FORECAST...WITH LIKELY POPS FOR NORTHWEST OHIO ON SATURDAY. MOST OF THE MODELS ARE ALSO HINTING AT A SECONDARY COLD FRONT SUNDAY NIGHT. WILL TRIM BACK TEMPERATURES A BIT BY MONDAY...A LITTLE BELOW NORMAL...FOR FEAR OF CLOUDS AND A COOLER NORTHWEST FLOW AS THE UPPER TROUGH SWINGS ACROSS THE AREA. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... A WARM FRONT WILL BE SLOWLY MOVING NORTH ACROSS THE AREA TODAY INTO TONIGHT. SEVERAL ROUNDS OF SHOWERS/STORMS ARE LIKELY AND IT WILL BE DIFFICULT TO TIME THE SHOWERS. THE CURRENT BATCH OF SHOWERS SHOULD MOVE EAST OF THE AREA MID MORNING. ANOTHER ROUND OF SHOWERS WILL PROBABLY REACH NORTHWEST OHIO EARLY THIS AFTERNOON AND SPREAD ACROSS THE FORECAST AREA THIS AFTERNOON. THUNDER IS POSSIBLE THIS MORNING BUT WILL LIMIT IT IN THE TAFS THIS MORNING BUT HAVE IT IN THE FORECAST FOR THIS AFTERNOON. ADDITIONAL SHOWERS ARE A GOOD BET ACROSS NORTHERN OHIO THE FIRST PART OF TONIGHT UNTIL THEY LIFT NORTH OF LAKE ERIE. .OUTLOOK...NON VFR POSSIBLE ON SATURDAY IN SHOWERS/THUNDERSTORMS. && .MARINE... A WARM FRONT OVER THE OHIO VALLEY WILL LIFT NORTH...CROSSING LAKE ERIE TONIGHT. THE WIND WILL VEER FROM THE EAST TO THE SOUTHEAST AND THEN THE SOUTH TODAY AND TONIGHT WITH THE PASSAGE OF THE WARM FRONT. HIGH PRESSURE OFF THE CAROLINA COAST WILL BUILD THIS WEEK. THE AIR MASS WILL BECOME WARM. THE STABILITY OVER THE COOLER LAKE WILL KEEP THE SOUTH TO SOUTHWEST WINDS LIGHT TO MODERATE ALL WEEK. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...OUDEMAN NEAR TERM...KIELTYKA/OUDEMAN SHORT TERM...OUDEMAN LONG TERM...KOSARIK AVIATION...KOSARIK MARINE...KOSARIK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
628 AM EDT TUE MAY 28 2013 .SYNOPSIS... WARM FRONT EXITING NORTHERN COUNTIES EARLY THIS MORNING. INCREASING HEAT/HUMIDITY THIS AFTERNOON TO END OF THE WEEK. NO ORGANIZED FRONTS IN VICINITY UNTIL WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AT 10Z ON THE GRAVEYARD SHIFT...SHALLOW SURFACE WARM FRONT NOW NORTH OF AREA. A MID LEVEL 700 MB TROF AXIS WAS DEPICTED ON RAP AND VAD WINDS NR ILN TO SDF AT 08Z...THEN CMH TO LEX AT 10Z. WEAK SUPPORT ASSOCIATED WITH THAT FEATURE CROSSES OUR NORTHERN ZONES 12Z THRU 15Z. SO HAVE SOME 20 TO 30 POPS ACROSS THE NORTH THIS MORNING FOR A LIGHT SHOWER. YET...RAP FORECASTING SOUTHERN EXTENSION OF THAT VORT AXIS DRAGGING THROUGH DURING THE LATE AFTERNOON. BOTH NAM AND GFS ON THEIR 00Z RUNS...SHOW MID LEVEL WARMING AT AROUND 8 TO 10 THSD FT TRYING TO FORM A CAP. SO WILL ONLY LEAVE SOME 20/30 POPS FOR THE POSSIBILITY OF A DIURNAL DRIVEN INSTABILITY SHOWER OR THUNDERSTORM TO FORM THIS AFTERNOON...MAINLY EAST AND SOUTH OF OHIO RIVER. THE WARM UP STARTS IN EARNEST TODAY. OVERALL NO BIG CHANGES TO OUR TEMPERATURE FORECAST. MARGINAL 850 MB MOISTURE LINGERS OVERNIGHT...SO PATCHES OF 4 TO 7 THSD FT CLOUDS MAY STILL BE HANGING AROUND LATE TONIGHT. OF COURSE...THIS CAUSES US HEADACHES TRYING TO FIGURE THE MINIMUM TEMPERATURE TONIGHT. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... UPPER RIDGE CONTINUES TO BUILD THROUGH THURSDAY AFTERNOON. TEMPERATURES WILL TOP OUT THURSDAY AFTERNOON WITH THE WARMEST READINGS SO FAR THIS YEAR. USED A MAV/MET BLEND FOR WEDNESDAY AND THURSDAY...WHICH BUMPED UP AFTERNOON HIGHS JUST A BIT EACH DAY. THE RIDGE STARTS BREAKING DOWN BY FRIDAY AS AN UPPER TROUGH BEGINS TO DROP INTO THE UPPER PLAINS. PRECIP WISE...HAVE DIURNAL SHOWERS AND STORMS IN THE WV MOUNTAINS EACH AFTERNOON DUE TO ELEVATED HEAT SOURCE INSTABILITY...AND ALSO INCLUDED SOME AFTERNOON CONVECTION IN SE OHIO FRIDAY AFTERNOON AS TEMPS ALOFT COOL A BIT AND A 500MB RIPPLE STREAMS ACROSS OHIO. && .LONG TERM /SATURDAY THROUGH MONDAY/... GFS/ECMWF BEGIN TO DIVERGE BY THE WEEKEND WITH THE POSITION OF THE COLD FRONT ASSOCIATED WITH OUR NEXT SYSTEM...GFS BREAKS THE RIDGE DOWN FASTER ALLOWING THE COLD FRONT TO ENTER OUR WESTERN COUNTIES EARLY SATURDAY WHILE THE ECMWF CONTINUES TO AMPLIFY THE RIDGE OVER THE SE STATES THROUGH SATURDAY NOT ALLOWING FOR FROPA ACROSS OUR CWA UNTIL LATER IN THE DAY SUNDAY...GIVEN THE MORE LINEAR SOLUTION OF THE GFS AND EXPECTED INFLUENCE OF CONVECTIVE PROCESSES ASSOCIATED WITH THE FRONT WILL PUT MORE WEIGHT ON ECMWF TIMING...ZONAL FLOW APPEARS TO MOVE IN BEHIND THE TROUGH OUT TO DAY 6 AND 7. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... PATCHY CEILINGS AT 6 TO 8 THSD FT 15Z WITH ISOLATED TO SCATTERED LIGHT SHOWERS POSSIBLE...MAINLY ACROSS EASTERN OHIO AND NORTHERN HALF OF WEST VIRGINIA. VSBY MAY LOWER BRIEFLY TO 6 OR 5 MILES. SCATTERED TO BROKEN CLOUDS AT 4 TO 5 THSD FT AGL 14Z THROUGH 23Z WITH INCREASING SURFACE WINDS FROM THE SOUTHWEST. ISOLATED CONVECTION MAY FORM 18Z TODAY TO 00Z WEDNESDAY. 00Z NAM AND GFS TRY TO WARM HE MID LEVELS AT 8 TO 10 THSD FT MSL JUST ENOUGH TO FORM CAP. YET...A WEAK VORT MAX AT 500 MB AND INCREASING SURFACE HEATING...HAS US STILL MENTIONING THE POSSIBILITY OF ISOLATED CONVECTION. MARGINAL 850 MB MOISTURE LINGERS TONIGHT AS SURFACE WINDS DECREASE. SO PATCHES OF 4 TO 6 THSD FT AGL SCATTERED TO BROKEN CLOUDS WITH CIRRUS ABOVE. SOME 5 TO 6 MILES IN HAZE MAY FORM IN THE MOUNTAIN VALLEYS VCNTY EKN FOR THE 06Z TO 12Z WEDNESDAY TIME FRAME. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: ISOLATED AFTERNOON CONVECTION MAY NOT FORM WITH DEVELOPING MID LEVEL WARMING/CAP. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z WEDNESDAY... NO WIDESPREAD IFR EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...JM AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
355 AM EDT TUE MAY 28 2013 .SYNOPSIS... WARM FRONT LIFTING NORTH SHOULD EXIT CWA THIS MORNING. INCREASING HEAT/HUMIDITY THIS AFTERNOON TO END OF THE WEEK. NO ORGANIZED FRONTS IN VICINITY UNTIL WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AT 07Z ON THE GRAVEYARD SHIFT...SHALLOW SURFACE WARM FRONT NOW NORTH OF PKB TO NEAR CKB/MGW. YET...925 MB FRONT ALREADY WELL TO THE NORTH. 925 MB WINDS ON VAD ABOUT 30 KNOTS...KEEPING SOME HILLTOPS MILDER THAN ADJACENT VALLEYS. A MID LEVEL 700 MB TROF AXIS WAS DEPICTED ON RAP AND VAD WINDS NR ILN TO SDF AT 08Z. WEAK SUPPORT ASSOCIATED WITH THAT FEATURE CROSSES OUR NORTHERN ZONES 12Z THRU 15Z. SO HAVE SOME 20 TO 30 POPS ACROSS THE NORTH THIS MORNING FOR A LIGHT SHOWER. YET...RAP FORECASTING SOUTHERN EXTENSION OF THAT VORT AXIS DRAGGING THROUGH DURING THE LATE AFTERNOON. BOTH NAM AND GFS ON THEIR 00Z RUNS...SHOW MID LEVEL WARMING AT AROUND 8 TO 10 THSD FT TRYING TO FORM A CAP. SO WILL ONLY LEAVE SOME 20/30 POPS FOR THE POSSIBILITY OF A DIURNAL DRIVEN INSTABILITY SHOWER OR THUNDERSTORM TO FORM THIS AFTERNOON...MAINLY EAST AND SOUTH OF OHIO RIVER. THE WARM UP STARTS IN EARNEST TODAY. OVERALL NO BIG CHANGES TO OUR TEMPERATURE FORECAST. MARGINAL 850 MB MOISTURE LINGERS OVERNIGHT...SO PATCHES OF 4 TO 7 THSD FT CLOUDS MAY STILL BE HANGING AROUND LATE TONIGHT. OF COURSE...THIS CAUSES US HEADACHES TRYING TO FIGURE THE MINIMUM TEMPERATURE TONIGHT. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... UPPER RIDGE CONTINUES TO BUILD THROUGH THURSDAY AFTERNOON. TEMPERATURES WILL TOP OUT THURSDAY AFTERNOON WITH THE WARMEST READINGS SO FAR THIS YEAR. USED A MAV/MET BLEND FOR WEDNESDAY AND THURSDAY...WHICH BUMPED UP AFTERNOON HIGHS JUST A BIT EACH DAY. THE RIDGE STARTS BREAKING DOWN BY FRIDAY AS AN UPPER TROUGH BEGINS TO DROP INTO THE UPPER PLAINS. PRECIP WISE...HAVE DIURNAL SHOWERS AND STORMS IN THE WV MOUNTAINS EACH AFTERNOON DUE TO ELEVATED HEAT SOURCE INSTABILITY...AND ALSO INCLUDED SOME AFTERNOON CONVECTION IN SE OHIO FRIDAY AFTERNOON AS TEMPS ALOFT COOL A BIT AND A 500MB RIPPLE STREAMS ACROSS OHIO. && .LONG TERM /SATURDAY THROUGH MONDAY/... GFS/ECMWF BEGIN TO DIVERGE BY THE WEEKEND WITH THE POSITION OF THE COLD FRONT ASSOCIATED WITH OUR NEXT SYSTEM...GFS BREAKS THE RIDGE DOWN FASTER ALLOWING THE COLD FRONT TO ENTER OUR WESTERN COUNTIES EARLY SATURDAY WHILE THE ECMWF CONTINUES TO AMPLIFY THE RIDGE OVER THE SE STATES THROUGH SATURDAY NOT ALLOWING FOR FROPA ACROSS OUR CWA UNTIL LATER IN THE DAY SUNDAY...GIVEN THE MORE LINEAR SOLUTION OF THE GFS AND EXPECTED INFLUENCE OF CONVECTIVE PROCESSES ASSOCIATED WITH THE FRONT WILL PUT MORE WEIGHT ON ECMWF TIMING...ZONAL FLOW APPEARS TO MOVE IN BEHIND THE TROUGH OUT TO DAY 6 AND 7. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... PATCHY CEILINGS AT 5 TO 8 THSD FT 06Z THROUGH 14Z WITH ISOLATED TO SCATTERED LIGHT SHOWERS POSSIBLE...MAINLY ACROSS EASTERN OHIO AND NORTHERN HALF OF WEST VIRGINIA. VSBY MAY LOWER BRIEFLY TO 5 MILES. SCATTERED TO BROKEN CLOUDS AT 4 TO 5 THSD FT AGL 14Z THROUGH 23Z WITH INCREASING SURFACE WINDS FROM THE SOUTHWEST. ISOLATED CONVECTION MAY FORM 18Z TODAY TO 00Z WEDNESDAY. 00Z NAM AND GFS TRY TO WARM HE MID LEVELS AT 8 TO 10 THSD FT MSL JUST ENOUGH TO FORM CAP. YET...A WEAK VORT MAX AT 500 MB AND INCREASING SURFACE HEATING...HAS US STILL MENTIONING THE POSSIBILITY OF ISOLATED CONVECTION. MARGINAL 850 MB MOISTURE LINGERS TONIGHT AS SURFACE WINDS DECREASE. SO PATCHES OF 4 TO 6 THSD FT AGL SCATTERED TO BROKEN CLOUDS. SOME 5 TO 6 MILES IN HAZE MAY FORM IN THE MOUNTAIN VALLEYS VCNTY EKN BY 06Z WEDNESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: ISOLATED AFTERNOON CONVECTION MAY NOT FORM WITH DEVELOP MID LEVEL WARMING/CAP. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE 05/28/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z WEDNESDAY... NO WIDESPREAD IFR EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...JM AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
345 AM EDT TUE MAY 28 2013 .SYNOPSIS... WARM FRONT LIFTING NORTH SHOULD EXIT CWA THIS MORNING. INCREASING HEAT/HUMIDITY THIS AFTERNOON TO END OF THE WEEK. NO ORGANIZED FRONTS IN VICINITY UNTIL WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AT 07Z ON THE GRAVEYARD SHIFT...SHALLOW SURFACE WARM FRONT NOW NORTH OF PKB TO NEAR CKB/MGW. YET...925 MB FRONT ALREADY WELL TO THE NORTH. 925 MB WINDS ON VAD ABOUT 30 KNOTS...KEEPING SOME HILLTOPS MILDER THAN ADJACENT VALLEYS. A MID LEVEL 700 MB TROF AXIS WAS DEPICTED ON RAP AND VAD WINDS NR ILN TO SDF AT 08Z. WEAK SUPPORT ASSOCIATED WITH THAT FEATURE CROSSES OUR NORTHERN ZONES 12Z THRU 15Z. SO HAVE SOME 20 TO 30 POPS ACROSS THE NORTH THIS MORNING FOR A LIGHT SHOWER. YET...RAP FORECASTING SOUTHERN EXTENSION OF THAT VORT AXIS DRAGGING THROUGH DURING THE LATE AFTERNOON. BOTH NAM AND GFS ON THEIR 00Z RUNS...SHOW MID LEVEL WARMING AT AROUND 8 TO 10 THSD FT TRYING TO FORM A CAP. SO WILL ONLY LEAVE SOME 20/30 POPS FOR THE POSSIBILITY OF A DIURNAL DRIVEN INSTABILITY SHOWER OR THUNDERSTORM TO FORM THIS AFTERNOON...MAINLY EAST AND SOUTH OF OHIO RIVER. THE WARM UP STARTS IN EARNEST TODAY. OVERALL NO BIG CHANGES TO OUR TEMPERATURE FORECAST. MARGINAL 850 MB MOISTURE LINGERS OVERNIGHT...SO PATCHES OF 4 TO 7 THSD FT CLOUDS MAY STILL BE HANGING AROUND LATE TONIGHT. OF COURSE...THIS CAUSES US HEADACHES TRYING TO FIGURE THE MINIMUM TEMPERATURE TONIGHT. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... && .LONG TERM /SATURDAY THROUGH MONDAY/... MODELS ARE IN STRONG AGREEMENT FOR THE FIRST PORTION OF THE LONG TERM FORECAST...THURSDAY THROUGH LATE FRIDAY...POSITIONING AN UPPER LEVEL LOW OVER THE NORTHERN GREAT LAKES WITH AN AMPLIFIED SURFACE HIGH CENTERED JUST OFF SHORE THE MID ATLANTIC STATES WITH A WELL ADVERTISED WARM UP IN FULL FORCE...HAVE KEPT SLIGHT POPS OVER PORTIONS OF EASTERN MTNS DUE TO MOISTURE RICH UPSLOPE FLOW THURSDAY AND FRIDAY...GFS/ECMWF BEGIN TO DIVERGE LATE FRIDAY WITH THE POSITION OF THE COLD FRONT ASSOCIATED WITH OUR NEXT SYSTEM...GFS BREAKS THE RIDGE DOWN FASTER ALLOWING THE COLD FRONT TO ENTER OUR WESTERN COUNTIES EARLY SATURDAY WHILE THE ECMWF CONTINUES TO AMPLIFY THE RIDGE OVER THE SE STATES THROUGH SATURDAY NOT ALLOWING FOR FROPA ACROSS OUR CWA UNTIL LATER IN THE DAY SUNDAY...GIVEN THE MORE LINEAR SOLUTION OF THE GFS AND EXPECTED INFLUENCE OF CONVECTIVE PROCESSES ASSOCIATED WITH THE FRONT WILL PUT MORE WEIGHT ON ECMWF TIMING...ZONAL FLOW APPEARS TO MOVE IN BEHIND THE TROUGH OUT TO DAY 6 AND 7... && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... PATCHY CEILINGS AT 5 TO 8 THSD FT 06Z THROUGH 14Z WITH ISOLATED TO SCATTERED LIGHT SHOWERS POSSIBLE...MAINLY ACROSS EASTERN OHIO AND NORTHERN HALF OF WEST VIRGINIA. VSBY MAY LOWER BRIEFLY TO 5 MILES. SCATTERED TO BROKEN CLOUDS AT 4 TO 5 THSD FT AGL 14Z THROUGH 23Z WITH INCREASING SURFACE WINDS FROM THE SOUTHWEST. ISOLATED CONVECTION MAY FORM 18Z TODAY TO 00Z WEDNESDAY. 00Z NAM AND GFS TRY TO WARM HE MID LEVELS AT 8 TO 10 THSD FT MSL JUST ENOUGH TO FORM CAP. YET...A WEAK VORT MAX AT 500 MB AND INCREASING SURFACE HEATING...HAS US STILL MENTIONING THE POSSIBILITY OF ISOLATED CONVECTION. MARGINAL 850 MB MOISTURE LINGERS TONIGHT AS SURFACE WINDS DECREASE. SO PATCHES OF 4 TO 6 THSD FT AGL SCATTERED TO BROKEN CLOUDS. SOME 5 TO 6 MILES IN HAZE MAY FORM IN THE MOUNTAIN VALLEYS VCNTY EKN BY 06Z WEDNESDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: ISOLATED AFTERNOON CONVECTION MAY NOT FORM WITH DEVELOP MID LEVEL WARMING/CAP. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE 05/28/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z WEDNESDAY... NO WIDESPREAD IFR EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...JM AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
158 AM EDT TUE MAY 28 2013 .SYNOPSIS... A WARM FRONT ACROSS THE AREA WILL LIFT NORTH OF THE REGION OVERNIGHT. A DISTURBANCE WILL APPROACH THE AREA ON TUESDAY BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS TO PORTIONS OF THE REGION. HIGH PRESSURE WILL BE PRESENT ACROSS THE AREA FOR THE MIDDLE OF THE WEEK BEFORE UNSETTLED WEATHER RETURNS FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SURFACE LOW IS PUSHING EAST ACROSS CENTRAL INDIANA WITH A WARM FRONT EXTENDING EAST ACROSS CENTRAL OHIO. SHOWERS AND THUNDERSTORMS ARE CONTINUING TO WORK EAST ALONG AND NORTH OF THE WARM FRONT...PRIMARILY AFFECTING OUR FAR NORTHERN COUNTIES. THESE SHOWERS/THUNDERSTORMS HAVE BEEN CONSISTENTLY WEAKENING AS THEY PUSH INTO OUR NORTHERN AREAS AND EXPECT THIS TREND TO CONTINUE BEFORE THEY GENERALLY TAPER OFF OVERNIGHT AS THE WARM LIFTS NORTH AND WE ALSO LOSE THE BETTER INSTABILITY. MEANWHILE A LINE OF THUNDERSTORMS IS MOVING EAST ALONG A TROUGH AXIS EXTENDING SOUTHWEST FROM THE LOW ACROSS SOUTHWEST INDIANA. EXPECT THESE TOO TO WEAKEN AS THEY PUSH EAST THROUGH LATE EVENING AND THE INSTABILITY BEGINS TO WEAKEN. THAT BEING SAID...THE EASTWARD EXTENT REMAINS SOMEWHAT IN DOUBT. THE LATEST HRRR IS TRYING TO SHOW SOME PCPN HOLDING TOGETHER INTO AT LEAST OUR SOUTHWESTERN AREAS SO WILL ALLOW FOR SOME LOW CHANCE POPS MAKING IT INTO AT LEAST OUR SOUTHWEST TOWARD MIDNIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... ANY REMAINING PRECIPITATION ACROSS THE FAR NORTHERN PORTIONS OF THE FA WILL TAPER OFF TUESDAY MORNING. A BRIEF LULL IN THE PRECIPITATION IS EXPECTED. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP DURING THE AFTERNOON HOURS AND MOVE INTO NW AND NORTHERN PORTIONS OF THE FA BY THE LATE AFTERNOON AND INTO THE EARLY EVENING HOURS. THERE IS DECENT INSTABILITY ACROSS THE FA DURING THE DAY ON TUESDAY. AS THESE STORMS DEVELOP AND MOVE INTO NORTHERN PORTIONS OF THE FORECAST AREA ON TUESDAY SOME OF THE STORMS COULD BE STRONG TO SEVERE WITH THE PRIMARY THREAT BEING DAMAGING WINDS. THIS ACTIVITY WILL DECREASE TUESDAY NIGHT AND DRY CONDITIONS WILL RETURN TO THE AREA. WINDS WILL INCREASE ACROSS THE AREA FOR THE DAYTIME HOURS ON TUESDAY WITH MODEL SOUNDINGS INDICATING SOME WIND GUSTS UPWARDS OF 30 MILES PER HOUR. WIND GUSTS WILL SLOWLY SUBSIDE TUESDAY NIGHT. WARM SOUTHERLY FLOW WILL ALLOW FOR TEMPERATURES TO RISE INTO THE 80S ACROSS THE ENTIRE FORECAST AREA FOR TUESDAY. WITH SOUTHERLY FLOW CONTINUING INTO TUESDAY NIGHT TEMPERATURES WILL ONLY DROP DOWN INTO THE 60S. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... UPPER LEVEL RIDGING WILL CAP THE REGION LEADING TO DRY AND VERY WARM CONDITIONS FOR THE MIDDLE PART OF THE WEEK. GUIDANCE IS TRENDING TOWARDS A SOMEWHAT QUICKER SUPPRESSION OF THE RIDGE. SO IT APPEARS THAT HEIGHTS WILL LOWER ENOUGH BY FRIDAY TO ALLOW FOR THE POTENTIAL OF DIURNAL CONVECTION ESPECIALLY IN THE NORTHWEST PART OF THE FORECAST AREA. EXPECT GREATER COVERAGE OF STORMS ON SATURDAY WITH STILL SOME DIURNAL COMPONENT. BUT A SHORT WAVE MOVING THROUGH THE GREAT LAKES WILL CAUSE A COLD FRONT TO MOVE TOWARDS THE AREA SATURDAY NIGHT AND SUNDAY AND PUSH IT OFF TO THE EAST SUNDAY NIGHT. THIS WILL BRING ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH THE REGION FROM LATER SATURDAY NIGHT INTO SUNDAY EVENING. THERE ARE SOME INDICATIONS THAT SHOWERS COULD LINGER INTO MONDAY WITH A SECONDARY TROUGH. BUT PROBABILITY IS LOW AT THIS POINT. TEMPERATURES WILL FALL BACK TO OR SLIGHTLY BELOW NORMAL FOR THE BEGINNING OF NEXT WEEK. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... SHOWERS AND THUNDERSTORMS CONTINUE NORTH OF THE TAF SITES ACROSS THE SRN GREAT LAKES REGION...ALONG AND NORTH OF A WARM FRONT. THE NORTHERN TAF SITES COULD SEE A WEAKENING SHOWER BUT CONDITIONS ARE EXPECTED TO REMAIN VFR WITH CIGS IN THE MID LEVELS BETWEEN 8000 AND 11000 FEET AGL. HAVE COVERED THIS THREAT WITH A MENTION OF VCSH. EXPECT A GENERAL LULL IN CONVECTIVE ACTIVITY DURG THE EARLY MORNING HOURS. WITH HEATING AIRMASS WILL ONCE AGAIN DESTABILIZE THROUGH THE AFTERNOON HOURS. THIS WILL LEAD TO SOME ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY MAINLY ACROSS THE NRN TAF SITES. IN THE WARM AIRMASS A CAP SHOULD INHIBIT CONVECTIVE DEVELOPMENT. WILL CONTINUE TO KEEP THE TAFS DRY AT THIS POINT WITH THE BEST CHANCE OF THUNDERSTORMS NORTH OF INTERSTATE 70...CLOSER TO THE WARM FRONT BOUNDARY. THE PRESSURE GRADIENT WILL TIGHTEN TODAY WITH SW WINDS GUSTING UP TO 28 KTS THIS AFTN. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...NOVAK NEAR TERM...JGL SHORT TERM...NOVAK LONG TERM... AVIATION...AR
AREA FORECAST DISCUSSION
NWS TULSA OK
1207 PM CDT TUE MAY 28 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD. THERE IS A CHANCE THAT ADDITIONAL MVFR CIGS COULD DEVELOP TOWARD SUNRISE AT THE OK TERMINALS...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE A CIG ATTM. WINDS WILL BE GUSTY THROUGH THE AFTERNOON...AND GUSTS WILL REDEVELOP AT ALL TERMINALS BY MID TO LATE MORNING TOMORROW. && .PREV DISCUSSION... /ISSUED 1049 AM CDT TUE MAY 28 2013/ ..UPDATE... DISCUSSION... SHOWERS AND THUNDERSTORMS ACROSS FAR NORTHEAST OKLAHOMA AND PARTS OF NORTHWEST ARKANSAS WILL CONTINUE TO MOVE OUT OF THE AREA BY THE AFTERNOON HOURS. SOME CLOUDINESS WILL LIKELY PERSIST THROUGH THE DAY...BUT AN OVERALL DECREASE IN CLOUD COVER WILL OCCUR TODAY. WILL GO AHEAD AND LEAVE HIGH TEMPERATURES AS IS FOR NOW...DUE TO THE CLOUD COVER. WIND GUSTS HAVE SO FAR REMAINED BELOW ADVISORY THRESHOLD...SO WILL NOT ISSUE ANYTHING FOR THAT AT THIS TIME. PREV DISCUSSION... /ISSUED 422 AM CDT TUE MAY 28 2013/ DISCUSSION... UPPER LEVEL TROUGH CONTINUES TO ORGANIZE TO OUR WEST THIS MORNING WITH PROFILER NETWORK ANALYZING A SWLY 55-65KT SOUTHWESTERLY LOW LEVEL JET ORIENTED OVER EASTERN OKLAHOMA. CLUSTER OF ELEVATED STORMS OVER CENTRAL MO SHOWING SIGNS OF BACK-BUILDING ALONG JET AXIS TOWARD NW ARKANSAS. ALSO AN APPARENT WAVE EMBEDDED IN WSW FLOW ALOFT TO OUR WEST. LOCAL MODEL AND HRRR LENDS SOME SUPPORT TO NAM SOLUTION OF BREAKING OUT PRECIP ACROSS NE OKLAHOMA THIS MORNING AND MAY NEED TO INCLUDE A SMALL CHANCE OF THUNDER FOR THE MORNING PERIOD. AIRMASS SHOULD ONCE AGAIN BECOME STRONGLY CAPPED THIS AFTERNOON WITH ANY LATER THUNDERSTORMS ASSOCIATED WITH DRY LINE FAR TO OUR WEST. WILL ONCE AGAIN SEE STRONG AND GUSTY SOUTH WINDS WITH A FEW GUSTS APPROACHING 40 MPH IN NE OKLAHOMA...BUT MUCH LIKE YESTERDAY IT APPEARS TOO MARGINAL FOR A WIND ADVISORY. MIXING MAY ALSO BE HAMPERED A BIT BY CLOUD COVER MUCH OF THE DAY. SIMILAR CONDITIONS EXPECTED WEDNESDAY. UPPER TROUGH WILL BECOME MORE NEGATIVELY TILTED WEDNESDAY AS STRONGER SHORTWAVE NOW MOVING ONSHORE SLIDES EAST. THIS WILL GIVE DRY LINE STORMS TO OUR WEST WED AFTERNOON AND EVENING BETTER SUPPORT TO ORGANIZE AND MOVE EAST OVERNIGHT INTO EASTERN OK AND POSSIBLY FAR NW ARKANSAS. THIS SHOULD MOVE OUT EARLY ENOUGH TO ALLOW ATMOSPHERE TO RECOVER THU AFTERNOON AND WITH UPPER JET IN FAVORABLE POSITION...THIS PERIOD WILL OFFER GREATEST THREAT FOR ORGANIZED SEVERE WEATHER ACROSS OUR AREA. FORECAST WIND PROFILES LOOK FAVORABLE FOR ALL MODES OF SEVERE WEATHER. COLD FRONT WILL EVENTUALLY PUSH THROUGH THE AREA LATE FRIDAY AND SATURDAY WITH THUNDERSTORM CHANCES INCREASING ONCE AGAIN. DRIER AIRMASS WILL MOVE IN FOR EARLY NEXT WEEK WITH A COUPLE OF PLEASANTLY COOL NIGHTS AND WARM DAYS. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...22 LONG TERM....23 AVIATION...22
AREA FORECAST DISCUSSION
NWS TULSA OK
1049 AM CDT TUE MAY 28 2013 ...UPDATE... .DISCUSSION... SHOWERS AND THUNDERSTORMS ACROSS FAR NORTHEAST OKLAHOMA AND PARTS OF NORTHWEST ARKANSAS WILL CONTINUE TO MOVE OUT OF THE AREA BY THE AFTERNOON HOURS. SOME CLOUDINESS WILL LIKELY PERSIST THROUGH THE DAY...BUT AN OVERALL DECREASE IN CLOUD COVER WILL OCCUR TODAY. WILL GO AHEAD AND LEAVE HIGH TEMPERATURES AS IS FOR NOW...DUE TO THE CLOUD COVER. WIND GUSTS HAVE SO FAR REMAINED BELOW ADVISORY THRESHOLD...SO WILL NOT ISSUE ANYTHING FOR THAT AT THIS TIME. && .PREV DISCUSSION... /ISSUED 422 AM CDT TUE MAY 28 2013/ DISCUSSION... UPPER LEVEL TROUGH CONTINUES TO ORGANIZE TO OUR WEST THIS MORNING WITH PROFILER NETWORK ANALYZING A SWLY 55-65KT SOUTHWESTERLY LOW LEVEL JET ORIENTED OVER EASTERN OKLAHOMA. CLUSTER OF ELEVATED STORMS OVER CENTRAL MO SHOWING SIGNS OF BACK-BUILDING ALONG JET AXIS TOWARD NW ARKANSAS. ALSO AN APPARENT WAVE EMBEDDED IN WSW FLOW ALOFT TO OUR WEST. LOCAL MODEL AND HRRR LENDS SOME SUPPORT TO NAM SOLUTION OF BREAKING OUT PRECIP ACROSS NE OKLAHOMA THIS MORNING AND MAY NEED TO INCLUDE A SMALL CHANCE OF THUNDER FOR THE MORNING PERIOD. AIRMASS SHOULD ONCE AGAIN BECOME STRONGLY CAPPED THIS AFTERNOON WITH ANY LATER THUNDERSTORMS ASSOCIATED WITH DRY LINE FAR TO OUR WEST. WILL ONCE AGAIN SEE STRONG AND GUSTY SOUTH WINDS WITH A FEW GUSTS APPROACHING 40 MPH IN NE OKLAHOMA...BUT MUCH LIKE YESTERDAY IT APPEARS TOO MARGINAL FOR A WIND ADVISORY. MIXING MAY ALSO BE HAMPERED A BIT BY CLOUD COVER MUCH OF THE DAY. SIMILAR CONDITIONS EXPECTED WEDNESDAY. UPPER TROUGH WILL BECOME MORE NEGATIVELY TILTED WEDNESDAY AS STRONGER SHORTWAVE NOW MOVING ONSHORE SLIDES EAST. THIS WILL GIVE DRY LINE STORMS TO OUR WEST WED AFTERNOON AND EVENING BETTER SUPPORT TO ORGANIZE AND MOVE EAST OVERNIGHT INTO EASTERN OK AND POSSIBLY FAR NW ARKANSAS. THIS SHOULD MOVE OUT EARLY ENOUGH TO ALLOW ATMOSPHERE TO RECOVER THU AFTERNOON AND WITH UPPER JET IN FAVORABLE POSITION...THIS PERIOD WILL OFFER GREATEST THREAT FOR ORGANIZED SEVERE WEATHER ACROSS OUR AREA. FORECAST WIND PROFILES LOOK FAVORABLE FOR ALL MODES OF SEVERE WEATHER. COLD FRONT WILL EVENTUALLY PUSH THROUGH THE AREA LATE FRIDAY AND SATURDAY WITH THUNDERSTORM CHANCES INCREASING ONCE AGAIN. DRIER AIRMASS WILL MOVE IN FOR EARLY NEXT WEEK WITH A COUPLE OF PLEASANTLY COOL NIGHTS AND WARM DAYS. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...22 LONG TERM....23
AREA FORECAST DISCUSSION
NWS TULSA OK
422 AM CDT TUE MAY 28 2013 .DISCUSSION... UPPER LEVEL TROUGH CONTINUES TO ORGANIZE TO OUR WEST THIS MORNING WITH PROFILER NETWORK ANALYZING A SWLY 55-65KT SOUTHWESTERLY LOW LEVEL JET ORIENTED OVER EASTERN OKLAHOMA. CLUSTER OF ELEVATED STORMS OVER CENTRAL MO SHOWING SIGNS OF BACK-BUILDING ALONG JET AXIS TOWARD NW ARKANSAS. ALSO AN APPARENT WAVE EMBEDDED IN WSW FLOW ALOFT TO OUR WEST. LOCAL MODEL AND HRRR LENDS SOME SUPPORT TO NAM SOLUTION OF BREAKING OUT PRECIP ACROSS NE OKLAHOMA THIS MORNING AND MAY NEED TO INCLUDE A SMALL CHANCE OF THUNDER FOR THE MORNING PERIOD. AIRMASS SHOULD ONCE AGAIN BECOME STRONGLY CAPPED THIS AFTERNOON WITH ANY LATER THUNDERSTORMS ASSOCIATED WITH DRY LINE FAR TO OUR WEST. WILL ONCE AGAIN SEE STRONG AND GUSTY SOUTH WINDS WITH A FEW GUSTS APPROACHING 40 MPH IN NE OKLAHOMA...BUT MUCH LIKE YESTERDAY IT APPEARS TOO MARGINAL FOR A WIND ADVISORY. MIXING MAY ALSO BE HAMPERED A BIT BY CLOUD COVER MUCH OF THE DAY. SIMILAR CONDITIONS EXPECTED WEDNESDAY. UPPER TROUGH WILL BECOME MORE NEGATIVELY TILTED WEDNESDAY AS STRONGER SHORTWAVE NOW MOVING ONSHORE SLIDES EAST. THIS WILL GIVE DRY LINE STORMS TO OUR WEST WED AFTERNOON AND EVENING BETTER SUPPORT TO ORGANIZE AND MOVE EAST OVERNIGHT INTO EASTERN OK AND POSSIBLY FAR NW ARKANSAS. THIS SHOULD MOVE OUT EARLY ENOUGH TO ALLOW ATMOSPHERE TO RECOVER THU AFTERNOON AND WITH UPPER JET IN FAVORABLE POSITION...THIS PERIOD WILL OFFER GREATEST THREAT FOR ORGANIZED SEVERE WEATHER ACROSS OUR AREA. FORECAST WIND PROFILES LOOK FAVORABLE FOR ALL MODES OF SEVERE WEATHER. COLD FRONT WILL EVENTUALLY PUSH THROUGH THE AREA LATE FRIDAY AND SATURDAY WITH THUNDERSTORM CHANCES INCREASING ONCE AGAIN. DRIER AIRMASS WILL MOVE IN FOR EARLY NEXT WEEK WITH A COUPLE OF PLEASANTLY COOL NIGHTS AND WARM DAYS. && .PRELIMINARY POINT TEMPS/POPS... TUL 85 72 83 70 / 10 10 20 70 FSM 87 69 86 68 / 10 10 10 50 MLC 84 72 83 71 / 10 10 20 50 BVO 84 70 83 70 / 10 10 20 70 FYV 83 66 81 68 / 10 10 10 60 BYV 84 68 82 67 / 10 10 10 60 MKO 85 69 82 67 / 10 10 10 70 MIO 86 69 84 68 / 10 10 10 60 F10 83 71 82 69 / 10 10 20 60 HHW 84 69 83 69 / 10 10 20 40 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...30 LONG TERM....14
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
640 PM EDT WED MAY 29 2013 .SYNOPSIS... WARMER AND MORE HUMID AIR WILL CONTINUE TO SPREAD ACROSS THE REGION AND STAY WILL US INTO THE UPCOMING WEEKEND. AN UPPER AIR DISTURBANCE CROSSING LAKE ERIE SHOULD FIRE OFF ONE OR TWO LINES OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING OVER MAINLY THE NORTHERN THIRD OF PENNSYLVANIA. SOME OF THE STORMS MAY PRODUCE STRONG WIND GUSTS AND HAIL. A STRENGTHENING UPPER LEVEL RIDGE WILL BUILD ALONG THE MID ATLANTIC REGION THROUGH THE END OF THE WEEK...KEEPING VERY WARM AND HUMID CONDITIONS IN THE FORECAST INTO THIS WEEKEND. A RATHER STRONG COLD FRONT WILL MOVE EAST ACROSS THE COMMONWEALTH SUNDAY...ACCOMPANIED BY SHOWERS AND SCATTERED THUNDERSTORMS. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... STILL A BROAD AREA OF MIXED LAYER CIN SITUATED ACROSS ALL OF THE WRN MTNS OF PENN AT 1730Z WITH A RIBBON OF RELATIVELY HIGHER ML CAPE AROUND 1500 J/KG DEVELOPING ACROSS THE ENTIRE SUSQ VALLEY. MID/UPPER LEVEL SHORT WAVE MOVING QUICKLY EAST ACROSS LAKE ERIE AND SOUTHERN ONTARIO /AND ABOVE A NE/SW RIBBON OF MDTLY STRONG LLVL THETA-E CONVERGENCE OVER LAKE ERIE WILL LIKELY FIRE-UP SOME TSRA JUST INLAND FROM THE SE SHORE OF LAKE ERIE DURING THE MID TO LATE AFTERNOON HOURS. LATEST 3 KM HRRR FORECAST REFLECTIVITY AND THE 4 KM NAM DIFFER A BIT IN THEIR ULTIMATE TRACK OF A POTENTIAL FAST-MOVING LINE OF TSRA /MCS/ THAT IS PROJECTED TO RACE ACROSS NRN PA AND SRN NEW LATER TODAY. THE NAM INITIATES CONVECTION OVER THE NW MTNS INVOF KBFD AND RAPIDLY PROPAGATES AN ORGANIZED MCS /WITH A DISTINCT...STRONG COLD POOL HIGHLIGHTED BY SURFACE TEMPS FALLING SHARPLY INTO THE M/U 60S ACROSS NORTH CENTRAL AND NORTHEASTERN PA LATE THIS AFTERNOON. AT THIS STAGE IN THE GAME...BOTH MODELS ARE A BIT BEHIND THE CURVE WITH RESPECT TO CONVECTIVE INITIATION...THANKS TO THE AFOREMENTIONED WEAK CIN ACROSS THE WRN MTNS. HIGH RES VISIBLE SATL IMAGERY SHOWS A QUICKLY DEVELOPING/DEEPENING CU FIELD JUST A FEW NM SOUTH OF THE LAKE ERIE. THESE CU SHOULD RAPIDLY GROW TO TSRA OVER THE NEXT 1-2 HOURS AS THE MID LEVEL CAP IS BROKEN AND WARM/UNSTABLE AIR /WITH SURFACE-BASED LIFTED INDICES AROUND -6/ IS ADVECTED NEWD. WITH MODERATE WESTERLIES AND SOMEWHAT OF AN INVERTED-V SOUNDING PRECEDING THIS LINE...DAMAGING WEST TO WNWRLY WIND GUSTS WILL BE POSSIBLE ALONG WITH HAIL...AND SPC HAS PLACED NORTHEAST PORTIONS OF CENTRAL PA IN SLIGHT RISK OUTLOOK FOR TODAY INTO TONIGHT. AMPLIFYING THERMAL RIDGE EXTENDS INTO SOUTHERN PA THIS AFTERNOON. +17C SHOULD NOSE INTO THE SOUTH CENTRAL MOUNTAINS BY 00Z TONIGHT...WHICH SHOULD BE SUFFICIENT TO SUPPORT MAXES IN THE U80S ACROSS THE SOUTH. THE NORTHERN AREAS SHOULD REACH THE LOWER 80S. THESE HIGHS ARE 10 TO 15 DEGREES ABOVE NORMAL. IN ADDITION...THE HUMIDITY WILL BE NOTICEABLE...AS DEWPOINTS RANGE FROM THE LOWER TO MIDDLE 60S. && .SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/... UPPER RIDGE WILL BUILD AND AMPLIFY TONIGHT AND THURSDAY...WITH RING OF FIRE CONVECTION SHIFTING NORTH OF THE AREA AS A STRONG MID-LEVEL CAP BUILDS AND POPS DECREASE AS A RESULT. SCT CONVECTION IN THE FORM OF SOME POTENTIALLY STRONG TSRA THIS EVENING...WILL BE MAINLY ACROSS THE NRN MTNS...AND OVER THE REGION TO THE EAST OF KIPT AND KSEG UNTIL AROUND 05Z...AS THE TAIL END OF THE UPPER SHORT WAVE /OR ASSOCIATED OUTFLOW BOUNDARIES FROM STORMS ACROSS NY STATE/ PUSHES ACROSS THAT PART OF THE STATE. PARTLY CLOUDY AND MILD CONDITIONS WILL FOLLOW FOR THE LATE NIGHT HOURS WITH AREAS OF FOG FORMING...AND BECOMING LOCALLY DENSE DAYBREAK /ESPECIALLY IN AREAS THAT RECEIVE SOME LATE DAY SHRA OR TSRA/. MINS WILL RANGE FROM THE UPPER 50S NORTH TO THE LOWER TO MIDDLE 60S SOUTH. A FEW DEG C OF WARMING ALOFT AND DEEP-LAYER RIDGING BUILDING NORTH INTO THE STATE WILL BRING A PARTLY TO MOSTLY SUNNY...AND VERY WARM DAY THURSDAY WITH VERY LITTLE /IF ANY/ CHANCE FOR A LATE DAY SHOWER OF TSRA. IT/S NOT OUT OF THE QUESTION TO SEE JUST A FEW...TERRAIN INDUCED LOW-TOPPED TSRA FORM AFTER 19Z ESPECIALLY ACROSS THE LAUREL AND SCENT MTNS. 850 MB TEMPS OF +17C TO +18C WILL SUPPORT HIGHS IN THE LOWER 90S ACROSS MUCH OF SOUTH CENTRAL AND SOUTHEAST PA...WITH MID TO UPPER 80S ACROSS THE NORTH. ANOTHER MILD AND SLIGHTLY MUGGY NIGHT IS IN STORE FOR THURSDAY NIGHT WITH LIGHT WIND AND MIN TEMPS RANGING FROM AROUND 60F ACROSS THE NRN AND WRN MTNS...TO THE LOWER AND MID 60S ELSEWHERE. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... UPPER RIDGE EXPECTED TO BE IN PLACE AT THE BEGINNING OF THE LONG TERM PERIOD WILL PERSIST INTO THE WEEKEND. RIDGE AXIS WILL BEGIN TO SHIFT EAST AS AN UPPER TROF MOVING EAST FROM THE NORTHERN PLAINS SWINGS THROUGH THE GREAT LAKES AND NEW ENGLAND THROUGH THE REMAINDER OF THE PERIOD. WITH THE UPPER RIDGE IN PLACE...THE LONG TERM PERIOD WILL BEGIN WITH SEVERAL DAYS OF VERY WARM AND HUMID BUT GENERALLY PCPN FREE WEATHER. SIGNIFICANT CHANCES FOR SHOWERS/TSTMS REMAIN CENTERED AROUND LATE SATURDAY...MUCH OF SUNDAY AND INTO MONDAY WHEN THE UPPER TROF AND ASSOCIATED COLD FRONT MOVE ACROSS THE STATE. THE FIRST FULL WEEK OF JUNE LOOKS TO BE SIGNIFICANTLY COOLER THAN THE FIRST COUPLE OF DAYS AS THE UPPER TROF DOMINATES THE REGION. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... VFR NOTED AT ALL TAF SITES THIS AFTERNOON. SFC WARM FRONT HAS LIFTED NORTH INTO SOUTHERN NEW YORK...WITH A 10-15KT SWRLY TO WESTERLY SFC WIND PRESENT ACROSS CENTRAL PENN. AN UPPER LEVEL DISTURBANCE LAKE ERIE AND WESTERN NEW YORK WILL BE RESPONSIBLE FOR THE DEVELOPMENT OF SOME FAST MOVING SHOWERS AND THUNDERSTORMS ACROSS MAINLY NRN PENN LATE TODAY AND EARLY TONIGHT. A FEW OF THE STORMS COULD TRY TO PUSH SOUTH ACROSS THE MID SUSQ VALLEY THIS EVENING TWD THE KSEG AND KMDT AREAS. EXPECT BRIEF...MAINLY MVFR CONDITIONS WITH THESE SHOWERS AND STORMS. THE MAIN PERIOD OF ADVERSE FLYING WEATHER WILL LIKELY BE BETWEEN 08-12Z THURSDAY...WHEN AREAS OF 1SM FOG /AND SOME LOCALLY DENSE WITH VSBYS AOB 1/4SM/ WILL DEVELOP IN THE HUMID AIRMASS WITH LIGHT WIND. CONDITIONS QUICKLY IMPROVE TO WIDESPREAD VFR BETWEEN 13-14Z THURSDAY AND STAY THAT WAY THROUGH AT LEAST EARLY THURSDAY NIGHT. .OUTLOOK... FRI AND SAT...MAINLY VFR. SOME RESTRICTIONS IN AM FOG AND HAZE POSSIBLE. ISOLATED LATE DAY THUNDERSTORMS POSSIBLE ACROSS MAINLY THE WESTERN HALF OF THE STATE SATURDAY. SUN...VFR TO MVFR IN AREAS OF THUNDERSTORMS AS A COLD FRONT APPROACHES FROM THE WEST. MON...MORNING LOW CIGS AND VSBYS POSSIBLE IN AREAS OF FOG...THEN VFR FOR THE LATE MORNING AND AFTERNOON. && .EQUIPMENT... NOAA WEATHER RADIO BROADCASTING ON A FREQUENCY OF 162.450 MHZ AND SERVING WARREN COUNTY...ALONG WITH PORTIONS OF MCKEAN...ELK AND FOREST COUNTIES...IS BACK IN OPERATION. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/LAMBERT NEAR TERM...LAMBERT SHORT TERM...DEVOIR LONG TERM...GARTNER AVIATION...LAMBERT EQUIPMENT...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
210 PM EDT WED MAY 29 2013 .SYNOPSIS... WARMER AND MORE HUMID AIR WILL CONTINUE TO SPREAD ACROSS THE REGION AND STAY WILL US INTO THE UPCOMING WEEKEND. AN UPPER AIR DISTURBANCE CROSSING LAKE ERIE SHOULD FIRE OFF ONE OR TWO LINES OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING OVER MAINLY THE NORTHERN THIRD OF PENNSYLVANIA. SOME OF THE STORMS MAY PRODUCE STRONG WIND GUSTS AND HAIL. A STRENGTHENING UPPER LEVEL RIDGE WILL BUILD ALONG THE MID ATLANTIC REGION THROUGH THE END OF THE WEEK...KEEPING VERY WARM AND HUMID CONDITIONS IN THE FORECAST INTO THIS WEEKEND. A RATHER STRONG COLD FRONT WILL MOVE EAST ACROSS THE COMMONWEALTH SUNDAY...ACCOMPANIED BY SHOWERS AND SCATTERED THUNDERSTORMS. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... STILL A BROAD AREA OF MIXED LAYER CIN SITUATED ACROSS ALL OF THE WRN MTNS OF PENN AT 1730Z WITH A RIBBON OF RELATIVELY HIGHER ML CAPE AROUND 1500 J/KG DEVELOPING ACROSS THE ENTIRE SUSQ VALLEY. MID/UPPER LEVEL SHORT WAVE MOVING QUICKLY EAST ACROSS LAKE ERIE AND SOUTHERN ONTARIO /AND ABOVE A NE/SW RIBBON OF MDTLY STRONG LLVL THETA-E CONVERGENCE OVER LAKE ERIE WILL LIKELY FIRE-UP SOME TSRA JUST INLAND FROM THE SE SHORE OF LAKE ERIE DURING THE MID TO LATE AFTERNOON HOURS. LATEST 3 KM HRRR FORECAST REFLECTIVITY AND THE 4 KM NAM DIFFER A BIT IN THEIR ULTIMATE TRACK OF A POTENTIAL FAST-MOVING LINE OF TSRA /MCS/ THAT IS PROJECTED TO RACE ACROSS NRN PA AND SRN NEW LATER TODAY. THE NAM INITIATES CONVECTION OVER THE NW MTNS INVOF KBFD AND RAPIDLY PROPAGATES AN ORGANIZED MCS /WITH A DISTINCT...STRONG COLD POOL HIGHLIGHTED BY SURFACE TEMPS FALLING SHARPLY INTO THE M/U 60S ACROSS NORTH CENTRAL AND NORTHEASTERN PA LATE THIS AFTERNOON. AT THIS STAGE IN THE GAME...BOTH MODELS ARE A BIT BEHIND THE CURVE WITH RESPECT TO CONVECTIVE INITIATION...THANKS TO THE AFOREMENTIONED WEAK CIN ACROSS THE WRN MTNS. HIGH RES VISIBLE SATL IMAGERY SHOWS A QUICKLY DEVELOPING/DEEPENING CU FIELD JUST A FEW NM SOUTH OF THE LAKE ERIE. THESE CU SHOULD RAPIDLY GROW TO TSRA OVER THE NEXT 1-2 HOURS AS THE MID LEVEL CAP IS BROKEN AND WARM/UNSTABLE AIR /WITH SURFACE-BASED LIFTED INDICES AROUND -6/ IS ADVECTED NEWD. WITH MODERATE WESTERLIES AND SOMEWHAT OF AN INVERTED-V SOUNDING PRECEDING THIS LINE...DAMAGING WEST TO WNWRLY WIND GUSTS WILL BE POSSIBLE ALONG WITH HAIL...AND SPC HAS PLACED NORTHEAST PORTIONS OF CENTRAL PA IN SLIGHT RISK OUTLOOK FOR TODAY INTO TONIGHT. AMPLIFYING THERMAL RIDGE EXTENDS INTO SOUTHERN PA THIS AFTERNOON. +17C SHOULD NOSE INTO THE SOUTH CENTRAL MOUNTAINS BY 00Z TONIGHT...WHICH SHOULD BE SUFFICIENT TO SUPPORT MAXES IN THE U80S ACROSS THE SOUTH. THE NORTHERN AREAS SHOULD REACH THE LOWER 80S. THESE HIGHS ARE 10 TO 15 DEGREES ABOVE NORMAL. IN ADDITION...THE HUMIDITY WILL BE NOTICEABLE...AS DEWPOINTS RANGE FROM THE LOWER TO MIDDLE 60S. && .SHORT TERM /10 PM THIS EVENING THROUGH THURSDAY NIGHT/... UPPER RIDGE WILL BUILD AND AMPLIFY TONIGHT AND THURSDAY...WITH RING OF FIRE CONVECTION SHIFTING NORTH OF THE AREA AS A STRONG MID-LEVEL CAP BUILDS AND POPS DECREASE AS A RESULT. SCT CONVECTION IN THE FORM OF SOME POTENTIALLY STRONG TSRA THIS EVENING...WILL BE MAINLY ACROSS THE NRN MTNS...AND OVER THE REGION TO THE EAST OF KIPT AND KSEG UNTIL AROUND 05Z...AS THE TAIL END OF THE UPPER SHORT WAVE /OR ASSOCIATED OUTFLOW BOUNDARIES FROM STORMS ACROSS NY STATE/ PUSHES ACROSS THAT PART OF THE STATE. PARTLY CLOUDY AND MILD CONDITIONS WILL FOLLOW FOR THE LATE NIGHT HOURS WITH AREAS OF FOG FORMING...AND BECOMING LOCALLY DENSE DAYBREAK /ESPECIALLY IN AREAS THAT RECEIVE SOME LATE DAY SHRA OR TSRA/. MINS WILL RANGE FROM THE UPPER 50S NORTH TO THE LOWER TO MIDDLE 60S SOUTH. A FEW DEG C OF WARMING ALOFT AND DEEP-LAYER RIDGING BUILDING NORTH INTO THE STATE WILL BRING A PARTLY TO MOSTLY SUNNY...AND VERY WARM DAY THURSDAY WITH VERY LITTLE /IF ANY/ CHANCE FOR A LATE DAY SHOWER OF TSRA. IT/S NOT OUT OF THE QUESTION TO SEE JUST A FEW...TERRAIN INDUCED LOW-TOPPED TSRA FORM AFTER 19Z ESPECIALLY ACROSS THE LAUREL AND SCENT MTNS. 850 MB TEMPS OF +17C TO +18C WILL SUPPORT HIGHS IN THE LOWER 90S ACROSS MUCH OF SOUTH CENTRAL AND SOUTHEAST PA...WITH MID TO UPPER 80S ACROSS THE NORTH. ANOTHER MILD AND SLIGHTLY MUGGY NIGHT IS IN STORE FOR THURSDAY NIGHT WITH LIGHT WIND AND MIN TEMPS RANGING FROM AROUND 60F ACROSS THE NRN AND WRN MTNS...TO THE LOWER AND MID 60S ELSEWHERE. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... AMPLIFIED UPPER RIDGE WILL REMAIN ALONG THE EASTERN SEABOARD DURING THE PERIOD AS AN UPPER TROF CLOSES OFF/MOVES EASTWARD ACROSS THE NORTHERN PLAINS AND INTO THE WRN GREAT LAKES. THIS WILL BRING ANOTHER WARM SPELL FOR MUCH OF THE EAST AS WE HEAD INTO THE BEGINNING OF JUNE. THE LONG TERM PERIOD WILL BEGIN WITH SEVERAL DAYS OF MAINLY DRY WEATHER WITH LITTLE IN THE WAY OF LARGE SCALE FORCING APPARENT. SRLY/SWRLY SFC WINDS WILL LEAD TO INCREASING SFC MOISTURE AND INSTABILITY...BUT SIGNIFICANT CHANCES FOR SHOWERS/TSTMS WILL HOLD OFF TIL LATER SATURDAY AND ESPECIALLY SUNDAY AND MONDAY WHEN A FRONT MOVES THROUGH THE UPPER FLOW AND INTO PA. A COOL DOWN FOR THE FIRST FULL WEEK OF JUNE MAY THEN BE IN THE OFFING FOR THE NORTHEAST...AS UPPER FLOW BECOMES QUITE TROFFY LOOKING IN SEVERAL OF THE LONG RANGE MODELS. && .AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... VFR NOTED AT ALL TAF SITES THIS AFTERNOON. SFC WARM FRONT HAS LIFTED NORTH INTO SOUTHERN NEW YORK...WITH A 10-15KT SWRLY TO WESTERLY SFC WIND PRESENT ACROSS CENTRAL PENN. AN UPPER LEVEL DISTURBANCE LAKE ERIE AND WESTERN NEW YORK WILL BE RESPONSIBLE FOR THE DEVELOPMENT OF SOME FAST MOVING SHOWERS AND THUNDERSTORMS ACROSS MAINLY NRN PENN LATE TODAY AND EARLY TONIGHT. A FEW OF THE STORMS COULD TRY TO PUSH SOUTH ACROSS THE MID SUSQ VALLEY THIS EVENING TWD THE KSEG AND KMDT AREAS. EXPECT BRIEF...MAINLY MVFR CONDITIONS WITH THESE SHOWERS AND STORMS. THE MAIN PERIOD OF ADVERSE FLYING WEATHER WILL LIKELY BE BETWEEN 08-12Z THURSDAY...WHEN AREAS OF 1SM FOG /AND SOME LOCALLY DENSE WITH VSBYS AOB 1/4SM/ WILL DEVELOP IN THE HUMID AIRMASS WITH LIGHT WIND. CONDITIONS QUICKLY IMPROVE TO WIDESPREAD VFR BETWEEN 13-14Z THURSDAY AND STAY THAT WAY THROUGH AT LEAST EARLY THURSDAY NIGHT. .OUTLOOK... FRI AND SAT...MAINLY VFR. SOME RESTRICTIONS IN AM FOG AND HAZE POSSIBLE. ISOLATED LATE DAY THUNDERSTORMS POSSIBLE ACROSS MAINLY THE WESTERN HALF OF THE STATE SATURDAY. SUN...VFR TO MVFR IN AREAS OF THUNDERSTORMS AS A COLD FRONT APPROACHES FROM THE WEST. MON...MORNING LOW CIGS AND VSBYS POSSIBLE IN AREAS OF FOG...THEN VFR FOR THE LATE MORNING AND AFTERNOON. && .EQUIPMENT... NOAA WEATHER RADIO BROADCASTING ON A FREQUENCY OF 162.450 MHZ AND SERVING WARREN COUNTY...ALONG WITH PORTIONS OF MCKEAN...ELK AND FOREST COUNTIES...IS BACK IN OPERATION. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...GARTNER AVIATION...LAMBERT EQUIPMENT...LAMBERT
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
347 PM CDT TUE MAY 28 2013 .SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM WITH THE MAIN WEATHER FEATURES. A LARGE NEGATIVELY TILTED UPPER LEVEL LOW PRESSURE TROUGH OVER THE SOUTHWEST US STILL SET TO KICK OUT INTO THE NORTHERN PLAINS WEDNESDAY THROUGH THURSDAY AND CLOSING OFF ACROSS OUR REGION. FOR TONIGHT...AN INITIAL WAVE WILL EJECT OUT TONIGHT INTO OUR REGION BRINGING AN MCS ACROSS MAINLY THE SOUTHERN CWA THIS EVENING AND OVERNIGHT. THE HRRR AND WRF MODELS BOTH SHOW AN MCS MOVING ACROSS SOUTHERN SD TONIGHT. FOR MUCH OF THE EASTERN CWA...IT WILL BE DRY THROUGH MUCH OF THE NIGHT. WITH CLEARING SKIES AND WINDS BECOMING LIGHT TONIGHT...EXPECT SOME MORE FOG TO FORM FROM THE JAMES VALLEY AND EAST TONIGHT AND REMAIN INTO WEDNESDAY MORNING. THE MODELS ALSO SHOW A GOOD LLJ ALONG WITH GOOD LOW AND MID LEVEL WAA DEVELOPING THROUGH THE NIGHT AND WEDNESDAY MORNING. THIS WILL AID IN NUMEROUS SHOWER AND THUNDERSTORM DEVELOPMENT LATER TONIGHT AND WEDNESDAY. BROAD SCALE UPPER LEVEL DIVERGENCE WITH THE UPPER TROUGH WILL CONTINUE TO PROVIDE GOOD ASCENT INTO WEDNESDAY NIGHT AND THURSDAY MORNING ACROSS THE CWA. THE MODELS ALL SHOW A GOOD SURFACE LOW PRESSURE AREA IN EASTERN COLORADO LIFTING NORTHEAST INTO NORTH DAKOTA WEDNESDAY AFTERNOON INTO THURSDAY EVENING AND DEEPENING. EVERYTHING IS SET FOR SOME SEVERE WEATHER POSSIBILITIES AND HEAVY RAIN DEVELOPMENT WEDNESDAY AND WEDNESDAY NIGHT. THE THING THAT MAY HOLD OFF MORE WIDESPREAD SEVERE WEATHER DEVELOPMENT WILL BE EARLY SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THE CWA AND CLOUD COVER THROUGH THE DAY AND EVENING WEDNESDAY. THIS WILL HOLD BACK THE DEVELOPMENT OF HIGH INSTABILITY. NONETHELESS...DEEP LAYER SHEAR...MOISTURE AND INSTABILITY WILL BE THERE FOR SOME SEVERE STORMS ALONG WITH HEAVY RAINFALL. MADE SOME CALLS IN THE HEAVY RAIN AREAS TODAY AND IT SEEMS MOST OF THE RAINFALL OVER THE LAST SEVERAL DAYS HAD SOAKED IN PRETTY GOOD. HAVE INCREASED CHANCES OF RAINFALL ACROSS THE REGION THROUGH WEDNESDAY NIGHT ALONG WITH ADDING IN THE MENTION OF HEAVY RAIN AND SEVERE WEATHER POSSIBILITIES. MUCH OF THE RAINFALL MAY END THURSDAY MORNING IN THE EASTERN CWA AS THE DRY LINE/COLD FRONT SWINGS IN QUICKLY THROUGH THE DAY BEHIND THE SURFACE LOW PRESSURE AREA. IN FACT...IT MAY BECOME WINDY ACROSS THE CWA THURSDAY AFTERNOON AND EVENING WITH A STRONG SURFACE LOW PRESSURE AREA TO THE NORTH ALONG WITH GOOD MIXING. LOWERED POPS FOR THURSDAY NIGHT ACROSS THE CWA. .LONG TERM...FRIDAY THROUGH TUESDAY THE PERIOD BEGINS WITH A LARGE UPPER LEVEL LOW PRESSURE SYSTEM SITUATED OVER THE NORTHERN PLAINS. THIS SYSTEM WILL BRING PERIODS OF SHOWERS AND PERHAPS A THUNDERSTORM OR TWO DURING THE AFTERNOON HOURS ON FRIDAY. CAPE VALUES ARE REDUCED SIGNIFICANTLY BY FRIDAY NIGHT SO WILL ONLY MENTION SHOWERS THROUGH THE WEEKEND. DEPENDING ON THE PLACEMENT OF THE LOW PRESSURE...HIGH TEMPERATURES ON SATURDAY COULD BE PRETTY CHILLY. THE 12Z RUN OF THE ECMWF IS SUGGESTING 925MB TEMPERATURES WILL ONLY WARM INTO THE MID/UPPER SINGLE DIGITS. THANKFULLY THE GFS/GEM DEPICT SLIGHTLY WARMER LOW LEVEL TEMPERATURES. OVERALL SATURDAY WILL BE CHILLY WITH HIGHS ONLY IN THE UPPER 50S...TO THE MID 60S EXPECTED. SUNDAY WILL MARK THE BEGINNING OF A WARMING TREND WITH TEMPERATURES FINALLY REACHING ABOVE NORMAL BY MONDAY. CHANCES FOR THUNDERSTORMS WILL RETURN TO THE FORECAST BY MONDAY NIGHT. A SURFACE LOW PRESSURE AND COLD FRONT SLIDING ACROSS THE REGION WILL BE THE FOCUS MECHANISM FOR CONVECTION. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE VALID TAF PERIOD FOR THE TERMINALS OF KPIR/KMBG. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE BETWEEN 02-06Z FOR KPIR. CONDITIONS MAY FALL TO MVFR RANGE UNDER STRONGER STORMS. IFR/MVFR CIGS OVER THE KABR/KATY TERMINALS SHOULD LIFT TO VFR RANGE BY MID AFTERNOON AND MAINTAIN VFR STATUS THROUGH THE REST OF THE TAF PERIOD. THAT SAID...DUE TO AN ABUNDANCE OF LOW LEVEL MOISTURE...IFR CONDITIONS ARE POSSIBLE FOR THE KATY TERMINAL TONIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...MOHR LONG TERM...SD AVIATION...SD WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
119 PM CDT TUE MAY 28 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 445 AM CDT TUE MAY 28 2013 REMNANTS OF OVERNIGHT CONVECTION MOVING THROUGH THE CWA THIS MORNING...WITH MCV TRACKING ALONG THE MISSOURI RIVER. MESOANALYSIS SHOWS VERY LITTLE IN THE WAY OF MUCAPE OVER OUR CWA...AND THUS AS EXPECTED THE AREA OF RAIN CONTINUES TO WEAKEN. EXPECT THIS TREND TO CONTINUE THROUGH THE MORNING. ANOTHER MAINLY DRY DAY IS THUS EXPECTED...WITH LARGE SCALE SUBSIDENCE OVERHEAD. CONCERNED ABOUT LOW STRATUS AND FOG LINGERING LONGER THAN PREVIOUSLY EXPECTED THOUGH. FLOW BECOMES PRETTY WEAK TODAY...WITH NOT MUCH OF A PUSH OF LOW LEVEL DRY AIR. THUS STRATUS SHOULD LINGER THROUGH THE MORNING...WITH SLOW CLEARING FROM WEST TO EAST THIS AFTERNOON. WENT AHEAD AND LOWERED HIGHS SEVERAL DEGREES TODAY...ESPECIALLY EAST OF THE JAMES RIVER. THESE HIGHS ARE MORE IN LINE WITH SOME OF THE NEWER GUIDANCE SUCH AS THE HRRR AND 4 KM NAM. LOOKING AT READINGS AROUND 70 SOUTHWEST MINNESOTA TO THE MID AND UPPER 70S ALONG THE MISSOURI RIVER. DAY SHIFT WILL HAVE TO MONITOR TRENDS...AS ADJUSTMENTS UP OR DOWN AREA LIKELY DEPENDING ON CLOUD COVER EVOLUTION...THUS ANOTHER LOW CONFIDENCE TEMPERATURE FORECAST. UNSETTLED WEATHER RETURNS TONIGHT INTO THURSDAY. LOW LEVEL JET INCREASES AGAIN TONIGHT...ADVECTING IN RICH THETAE AIR AND HIGH PWATS. MEANWHILE IT SEEMS LIKELY THAT CONVECTION WILL FIRE THIS AFTERNOON ACROSS THE NEBRASKA PANHANDLE AND WESTERN SOUTH DAKOTA AS ANOTHER WAVE BEGINS TO EJECT OUT OF THE ROCKIES...AND THIS EVOLUTION IS SUPPORTED BY ALMOST ALL HI RES GUIDANCE. THIS AREA OF CONVECTION SHOULD WEAKEN AS IT APPROACHES OUR AREA...AS DESPITE THE THETAE ADVECTION...WE DRY OUT ENOUGH TODAY THAT WE DONT QUITE COMPLETELY RECOVER IN TIME. HOWEVER MAY SEE THE LINE OF STORMS MAKE IT INTO OUR FAR WESTERN COUNTIES AFTER 03Z BEFORE IT DOES DISSIPATE...AND THUS CAN NOT RULE OUT AN ISOLATED SEVERE WIND GUST WITH THAT ACTIVITY. EVENTUALLY THE CONTINUED THETAE ADVECTION BECOMES ENOUGH TO SATURATE US ENOUGH AND DEVELOP ELEVATED INSTABILITY. THUS THOUGHT IS SHOWERS AND STORMS START BECOMING MORE NUMEROUS BY EARLY WEDNESDAY MORNING AND THROUGH THE DAY. NOT SEEING MUCH TOO MUCH OF A SEVERE THREAT WITH THIS ACTIVITY AS SOUNDINGS EXHIBIT MORE OF A HEAVY RAIN SATURATED THIN CAPE PROFILE. HOWEVER WIND FIELDS ARE STRONGER...THUS A FEW MARGINAL SEVERE STORMS ARE POSSIBLE WITH THIS ACTIVITY ANYTIME WEDNESDAY. TOUGH TO PINPOINT EXACTLY WHERE THE HEAVIEST OF THE RAIN ENDS UP GOING. BUT HI RES MODEL SOLUTIONS SEEM TO FAVOR MUCH OF THE HEAVIER ACTIVITY WEDNESDAY ALONG AND EAST OF INTERSTATE 29...WITH CONVECTION CONTINUOUSLY DEVELOPING ACROSS CENTRAL OR EASTERN NEBRASKA AND MOVING NORTH NORTHEAST WITH THE MEAN WIND. GIVEN THE TRAINING POTENTIAL AND HIGH PWATS...WEDNESDAY LOOKS TO BE A DAY WITH AN ELEVATED FLOODING POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 445 AM CDT TUE MAY 28 2013 WE MAY SEE A BREAK FOR A PERIOD LATER WEDNESDAY AFTERNOON INTO THE EVENING AS THE TRAINING WAA CONVECTION SHIFTS EAST OF THE CWA. HOWEVER ATTENTION THEN TURNS YO OUR WEST AS THE MAIN WAVE MOVES INTO THE PLAINS. A LARGE AREA OF THUNDERSTORMS SHOULD FIRE ACROSS THE WESTERN PLAINS WITH THIS WAVE...AND THEN MOVE INTO OUR CWA ANYTIME FROM THE EVENING INTO THE OVERNIGHT. DUE TO CONSIDERABLE CLOUD COVER INSTABILITY MAY NOT BE TOO HIGH...BUT WIND FIELDS SHOULD BE STRONG ENOUGH TI SUPPORT ORGANIZED CONVECTION. THUS THINKING OUR GREATEST SEVERE THREAT MAY END UP BEING WITH THIS ACTIVITY WEDNESDAY EVENING OR NIGHT. A FEW SUPERCELLS POSSIBLE IN OUR WEST...BUT TIMING SUGGESTS THAT THE CONVECTION WOULD PROBABLY BE LINEAR BY THE TIME IT IMPACTS MOST OF OUR CWA...WITH STRONG WINDS THE GREATEST THREAT. GIVEN THE POTENTIAL OF HEAVY RAIN EARLIER WEDNESDAY...ANY ADDITIONAL RAIN WOULD ALSO ENHANCE THE FLOODING POTENTIAL. MODELS CONTINUE TO SPEED UP THE MOVEMENT OF THE WAVE. THUS BY THURSDAY THE GREATEST THUNDERSTORM THREAT SHOULD BE EAST OF INTERSTATE 29...AND DURING THE FIRST PORTION OF THE DAY. THUS SEVERE THREAT ON THURSDAY SHOULD END UP SOUTH AND EAST OF OUR CWA. BY LATER THURSDAY AFTERNOON INTO THE OVERNIGHT THERE MAY NOT BE MUCH GOING ON ACROSS OUR AREA. GOING WITH HIGHS IN THE 70S BOTH WEDNESDAY AND THURSDAY...BUT THIS AGAIN DEPENDENT ON CLOUD COVER. AREAS THAT SEE SUN COULD REACH THE 80S BOTH DAYS...WHILE 60S ARE A POSSIBILITY WHERE CLOUDS HOLD TOUGH. THE PERSISTENT UPPER LOW OVER THE WESTERN UNITED STATES FINALLY LIFTS NORTHEASTWARD TOWARD ND AND MN LATE THIS WEEK AND THROUGH THE WEEKEND. THIS MEANS QUIETER WEATHER FOR OUR AREA. ALTHOUGH ONE CANNOT RULE OUT A FEW SHOWERS OR ISOLATED THUNDERSTORMS IN OUR FORECAST AREA FRIDAY AND SATURDAY...THE CHANCES OF ANY ONE LOCATION GETTING A WETTING RAIN IS FAIRLY REMOTE. DRY WEATHER LOOKS TO PREVAIL ON SUNDAY AND MONDAY. IN RESPONSE TO THE UPPER LOW LIFTING CLOSER TO THE CANADIAN BORDER...COOL SURFACE HIGH PRESSURE WILL THEN FILTER DOWN PROMISING MUCH BELOW NORMAL TEMPERATURES FOR THE WEEKEND. ON FRIDAY AND MONDAY...70S SHOULD BE MORE WIDESPREAD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 114 PM CDT TUE MAY 28 2013 MVFR CEILINGS QUICKLY ADVECTING EAST EARLY THIS AFTERNOON AND EXPECT THIS TREND TO CONTINUE THROUGH THE EVENING. VFR CONDITIONS SHOULD PREVAIL MUCH OF THE NIGHT BUT A CLUSTER OF THUNDERSTORMS SHOULD MOVE FROM THE WESTERN HIGH PLAINS INTO THE AREA AFTER ABOUT 08Z. AHEAD OF THIS CLUSTER ADDITIONAL THUNDERSTORMS MAY DEVELOP AROUND THE MISSOURI RIVER VALLEY AND ADVECT NORTHWARD WEDNESDAY MORNING. THE BETTER CHANCE FOR THUNDERSTORMS WILL LIKELY BE FROM ABOUT 11Z THROUGH 18Z. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...CHENARD/MJF AVIATION...08
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
634 AM CDT TUE MAY 28 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 445 AM CDT TUE MAY 28 2013 REMNANTS OF OVERNIGHT CONVECTION MOVING THROUGH THE CWA THIS MORNING...WITH MCV TRACKING ALONG THE MISSOURI RIVER. MESOANALYSIS SHOWS VERY LITTLE IN THE WAY OF MUCAPE OVER OUR CWA...AND THUS AS EXPECTED THE AREA OF RAIN CONTINUES TO WEAKEN. EXPECT THIS TREND TO CONTINUE THROUGH THE MORNING. ANOTHER MAINLY DRY DAY IS THUS EXPECTED...WITH LARGE SCALE SUBSIDENCE OVERHEAD. CONCERNED ABOUT LOW STRATUS AND FOG LINGERING LONGER THAN PREVIOUSLY EXPECTED THOUGH. FLOW BECOMES PRETTY WEAK TODAY...WITH NOT MUCH OF A PUSH OF LOW LEVEL DRY AIR. THUS STRATUS SHOULD LINGER THROUGH THE MORNING...WITH SLOW CLEARING FROM WEST TO EAST THIS AFTERNOON. WENT AHEAD AND LOWERED HIGHS SEVERAL DEGREES TODAY...ESPECIALLY EAST OF THE JAMES RIVER. THESE HIGHS ARE MORE IN LINE WITH SOME OF THE NEWER GUIDANCE SUCH AS THE HRRR AND 4 KM NAM. LOOKING AT READINGS AROUND 70 SOUTHWEST MINNESOTA TO THE MID AND UPPER 70S ALONG THE MISSOURI RIVER. DAY SHIFT WILL HAVE TO MONITOR TRENDS...AS ADJUSTMENTS UP OR DOWN AREA LIKELY DEPENDING ON CLOUD COVER EVOLUTION...THUS ANOTHER LOW CONFIDENCE TEMPERATURE FORECAST. UNSETTLED WEATHER RETURNS TONIGHT INTO THURSDAY. LOW LEVEL JET INCREASES AGAIN TONIGHT...ADVECTING IN RICH THETAE AIR AND HIGH PWATS. MEANWHILE IT SEEMS LIKELY THAT CONVECTION WILL FIRE THIS AFTERNOON ACROSS THE NEBRASKA PANHANDLE AND WESTERN SOUTH DAKOTA AS ANOTHER WAVE BEGINS TO EJECT OUT OF THE ROCKIES...AND THIS EVOLUTION IS SUPPORTED BY ALMOST ALL HI RES GUIDANCE. THIS AREA OF CONVECTION SHOULD WEAKEN AS IT APPROACHES OUR AREA...AS DESPITE THE THETAE ADVECTION...WE DRY OUT ENOUGH TODAY THAT WE DONT QUITE COMPLETELY RECOVER IN TIME. HOWEVER MAY SEE THE LINE OF STORMS MAKE IT INTO OUR FAR WESTERN COUNTIES AFTER 03Z BEFORE IT DOES DISSIPATE...AND THUS CAN NOT RULE OUT AN ISOLATED SEVERE WIND GUST WITH THAT ACTIVITY. EVENTUALLY THE CONTINUED THETAE ADVECTION BECOMES ENOUGH TO SATURATE US ENOUGH AND DEVELOP ELEVATED INSTABILITY. THUS THOUGHT IS SHOWERS AND STORMS START BECOMING MORE NUMEROUS BY EARLY WEDNESDAY MORNING AND THROUGH THE DAY. NOT SEEING MUCH TOO MUCH OF A SEVERE THREAT WITH THIS ACTIVITY AS SOUNDINGS EXHIBIT MORE OF A HEAVY RAIN SATURATED THIN CAPE PROFILE. HOWEVER WIND FIELDS ARE STRONGER...THUS A FEW MARGINAL SEVERE STORMS ARE POSSIBLE WITH THIS ACTIVITY ANYTIME WEDNESDAY. TOUGH TO PINPOINT EXACTLY WHERE THE HEAVIEST OF THE RAIN ENDS UP GOING. BUT HI RES MODEL SOLUTIONS SEEM TO FAVOR MUCH OF THE HEAVIER ACTIVITY WEDNESDAY ALONG AND EAST OF INTERSTATE 29...WITH CONVECTION CONTINUOUSLY DEVELOPING ACROSS CENTRAL OR EASTERN NEBRASKA AND MOVING NORTH NORTHEAST WITH THE MEAN WIND. GIVEN THE TRAINING POTENTIAL AND HIGH PWATS...WEDNESDAY LOOKS TO BE A DAY WITH AN ELEVATED FLOODING POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 445 AM CDT TUE MAY 28 2013 WE MAY SEE A BREAK FOR A PERIOD LATER WEDNESDAY AFTERNOON INTO THE EVENING AS THE TRAINING WAA CONVECTION SHIFTS EAST OF THE CWA. HOWEVER ATTENTION THEN TURNS YO OUR WEST AS THE MAIN WAVE MOVES INTO THE PLAINS. A LARGE AREA OF THUNDERSTORMS SHOULD FIRE ACROSS THE WESTERN PLAINS WITH THIS WAVE...AND THEN MOVE INTO OUR CWA ANYTIME FROM THE EVENING INTO THE OVERNIGHT. DUE TO CONSIDERABLE CLOUD COVER INSTABILITY MAY NOT BE TOO HIGH...BUT WIND FIELDS SHOULD BE STRONG ENOUGH TI SUPPORT ORGANIZED CONVECTION. THUS THINKING OUR GREATEST SEVERE THREAT MAY END UP BEING WITH THIS ACTIVITY WEDNESDAY EVENING OR NIGHT. A FEW SUPERCELLS POSSIBLE IN OUR WEST...BUT TIMING SUGGESTS THAT THE CONVECTION WOULD PROBABLY BE LINEAR BY THE TIME IT IMPACTS MOST OF OUR CWA...WITH STRONG WINDS THE GREATEST THREAT. GIVEN THE POTENTIAL OF HEAVY RAIN EARLIER WEDNESDAY...ANY ADDITIONAL RAIN WOULD ALSO ENHANCE THE FLOODING POTENTIAL. MODELS CONTINUE TO SPEED UP THE MOVEMENT OF THE WAVE. THUS BY THURSDAY THE GREATEST THUNDERSTORM THREAT SHOULD BE EAST OF INTERSTATE 29...AND DURING THE FIRST PORTION OF THE DAY. THUS SEVERE THREAT ON THURSDAY SHOULD END UP SOUTH AND EAST OF OUR CWA. BY LATER THURSDAY AFTERNOON INTO THE OVERNIGHT THERE MAY NOT BE MUCH GOING ON ACROSS OUR AREA. GOING WITH HIGHS IN THE 70S BOTH WEDNESDAY AND THURSDAY...BUT THIS AGAIN DEPENDENT ON CLOUD COVER. AREAS THAT SEE SUN COULD REACH THE 80S BOTH DAYS...WHILE 60S ARE A POSSIBILITY WHERE CLOUDS HOLD TOUGH. / THE PERSISTENT UPPER LOW OVER THE WESTERN UNITED STATES FINALLY LIFTS NORTHEASTWARD TOWARD ND AND MN LATE THIS WEEK AND THROUGH THE WEEKEND. THIS MEANS QUIETER WEATHER FOR OUR AREA. ALTHOUGH ONE CANNOT RULE OUT A FEW SHOWERS OR ISOLATED THUNDERSTORMS IN OUR FORECAST AREA FRIDAY AND SATURDAY...THE CHANCES OF ANY ONE LOCATION GETTING A WETTING RAIN IS FAIRLY REMOTE. DRY WEATHER LOOKS TO PREVAIL ON SUNDAY AND MONDAY. IN RESPONSE TO THE UPPER LOW LIFTING CLOSER TO THE CANADIAN BORDER...COOL SURFACE HIGH PRESSURE WILL THEN FILTER DOWN PROMISING MUCH BELOW NORMAL TEMPERATURES FOR THE WEEKEND. ON FRIDAY AND MONDAY...70S SHOULD BE MORE WIDESPREAD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 633 AM CDT TUE MAY 28 2013 WIDESPREAD LIFR TO VLIFR CONDITIONS EXISTS EARLY TODAY ALONG AND EAST OF INTERSTATE 29. CURRENTLY JUST BEFORE 12Z...KSUX IS SHOWING VFR CONDITIONS. HOWEVER WHAT WIND THEY HAVE APPEARS TO BE GOING EASTERLY AND THE CITY WEBCAMS LOOK VERY SOUPY. THEREFORE AM CONCERNED THAT THE LIFR CONDITIONS WILL BEGIN TO ADVECT INTO THAT LOCATION SHORTLY. SO HEDGED SOME STRATUS IN THERE BEGINNING AT 14Z...AND WILL MONITOR CLOSELY FOR ARRIVAL OR LACK OF ARRIVAL OF THESE POOR CONDITIONS. SIMILARLY AT KHON...THEY ARE VFR. THEIR WEBCAM CONFIRMS SOME PRETTY SOLID VFR AT THE MOMENT. BUT WITH MITCHELL AND BROOKING SD SEEING LIFR CEILINGS...AM ALSO A BIT WORRIED THAT KHON LATER THIS MORNING COULD SEE AT LEAST SOME BROKEN CEILINGS IN THE IFR TO LOWER MVFR CATEGORY. KFSD IS SOLIDLY LIFR. VARIOUS MODELS POINT TO A CLEARING TREND THIS AFTERNOON WITH A SCOURING OUT OF THE STRATUS. THEREFORE TRENDED THE TAF SITES TOWARD VFR THIS AFTERNOON AND EVENING. WATCH FOR MORE THUNDERSTORMS TO DEVELOP LATE TONIGHT ALONG AND SOUTH OF INTERSTATE 90. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ071-072- 080-081-089-090-097-098. IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ001>003- 012>014-021-022. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...CHENARD/MJF AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
448 AM CDT TUE MAY 28 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 445 AM CDT TUE MAY 28 2013 REMNANTS OF OVERNIGHT CONVECTION MOVING THROUGH THE CWA THIS MORNING...WITH MCV TRACKING ALONG THE MISSOURI RIVER. MESOANALYSIS SHOWS VERY LITTLE IN THE WAY OF MUCAPE OVER OUR CWA...AND THUS AS EXPECTED THE AREA OF RAIN CONTINUES TO WEAKEN. EXPECT THIS TREND TO CONTINUE THROUGH THE MORNING. ANOTHER MAINLY DRY DAY IS THUS EXPECTED...WITH LARGE SCALE SUBSIDENCE OVERHEAD. CONCERNED ABOUT LOW STRATUS AND FOG LINGERING LONGER THAN PREVIOUSLY EXPECTED THOUGH. FLOW BECOMES PRETTY WEAK TODAY...WITH NOT MUCH OF A PUSH OF LOW LEVEL DRY AIR. THUS STRATUS SHOULD LINGER THROUGH THE MORNING...WITH SLOW CLEARING FROM WEST TO EAST THIS AFTERNOON. WENT AHEAD AND LOWERED HIGHS SEVERAL DEGREES TODAY...ESPECIALLY EAST OF THE JAMES RIVER. THESE HIGHS ARE MORE IN LINE WITH SOME OF THE NEWER GUIDANCE SUCH AS THE HRRR AND 4 KM NAM. LOOKING AT READINGS AROUND 70 SOUTHWEST MINNESOTA TO THE MID AND UPPER 70S ALONG THE MISSOURI RIVER. DAY SHIFT WILL HAVE TO MONITOR TRENDS...AS ADJUSTMENTS UP OR DOWN AREA LIKELY DEPENDING ON CLOUD COVER EVOLUTION...THUS ANOTHER LOW CONFIDENCE TEMPERATURE FORECAST. UNSETTLED WEATHER RETURNS TONIGHT INTO THURSDAY. LOW LEVEL JET INCREASES AGAIN TONIGHT...ADVECTING IN RICH THETAE AIR AND HIGH PWATS. MEANWHILE IT SEEMS LIKELY THAT CONVECTION WILL FIRE THIS AFTERNOON ACROSS THE NEBRASKA PANHANDLE AND WESTERN SOUTH DAKOTA AS ANOTHER WAVE BEGINS TO EJECT OUT OF THE ROCKIES...AND THIS EVOLUTION IS SUPPORTED BY ALMOST ALL HI RES GUIDANCE. THIS AREA OF CONVECTION SHOULD WEAKEN AS IT APPROACHES OUR AREA...AS DESPITE THE THETAE ADVECTION...WE DRY OUT ENOUGH TODAY THAT WE DONT QUITE COMPLETELY RECOVER IN TIME. HOWEVER MAY SEE THE LINE OF STORMS MAKE IT INTO OUR FAR WESTERN COUNTIES AFTER 03Z BEFORE IT DOES DISSIPATE...AND THUS CAN NOT RULE OUT AN ISOLATED SEVERE WIND GUST WITH THAT ACTIVITY. EVENTUALLY THE CONTINUED THETAE ADVECTION BECOMES ENOUGH TO SATURATE US ENOUGH AND DEVELOP ELEVATED INSTABILITY. THUS THOUGHT IS SHOWERS AND STORMS START BECOMING MORE NUMEROUS BY EARLY WEDNESDAY MORNING AND THROUGH THE DAY. NOT SEEING MUCH TOO MUCH OF A SEVERE THREAT WITH THIS ACTIVITY AS SOUNDINGS EXHIBIT MORE OF A HEAVY RAIN SATURATED THIN CAPE PROFILE. HOWEVER WIND FIELDS ARE STRONGER...THUS A FEW MARGINAL SEVERE STORMS ARE POSSIBLE WITH THIS ACTIVITY ANYTIME WEDNESDAY. TOUGH TO PINPOINT EXACTLY WHERE THE HEAVIEST OF THE RAIN ENDS UP GOING. BUT HI RES MODEL SOLUTIONS SEEM TO FAVOR MUCH OF THE HEAVIER ACTIVITY WEDNESDAY ALONG AND EAST OF INTERSTATE 29...WITH CONVECTION CONTINUOUSLY DEVELOPING ACROSS CENTRAL OR EASTERN NEBRASKA AND MOVING NORTH NORTHEAST WITH THE MEAN WIND. GIVEN THE TRAINING POTENTIAL AND HIGH PWATS...WEDNESDAY LOOKS TO BE A DAY WITH AN ELEVATED FLOODING POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 445 AM CDT TUE MAY 28 2013 WE MAY SEE A BREAK FOR A PERIOD LATER WEDNESDAY AFTERNOON INTO THE EVENING AS THE TRAINING WAA CONVECTION SHIFTS EAST OF THE CWA. HOWEVER ATTENTION THEN TURNS YO OUR WEST AS THE MAIN WAVE MOVES INTO THE PLAINS. A LARGE AREA OF THUNDERSTORMS SHOULD FIRE ACROSS THE WESTERN PLAINS WITH THIS WAVE...AND THEN MOVE INTO OUR CWA ANYTIME FROM THE EVENING INTO THE OVERNIGHT. DUE TO CONSIDERABLE CLOUD COVER INSTABILITY MAY NOT BE TOO HIGH...BUT WIND FIELDS SHOULD BE STRONG ENOUGH TI SUPPORT ORGANIZED CONVECTION. THUS THINKING OUR GREATEST SEVERE THREAT MAY END UP BEING WITH THIS ACTIVITY WEDNESDAY EVENING OR NIGHT. A FEW SUPERCELLS POSSIBLE IN OUR WEST...BUT TIMING SUGGESTS THAT THE CONVECTION WOULD PROBABLY BE LINEAR BY THE TIME IT IMPACTS MOST OF OUR CWA...WITH STRONG WINDS THE GREATEST THREAT. GIVEN THE POTENTIAL OF HEAVY RAIN EARLIER WEDNESDAY...ANY ADDITIONAL RAIN WOULD ALSO ENHANCE THE FLOODING POTENTIAL. MODELS CONTINUE TO SPEED UP THE MOVEMENT OF THE WAVE. THUS BY THURSDAY THE GREATEST THUNDERSTORM THREAT SHOULD BE EAST OF INTERSTATE 29...AND DURING THE FIRST PORTION OF THE DAY. THUS SEVERE THREAT ON THURSDAY SHOULD END UP SOUTH AND EAST OF OUR CWA. BY LATER THURSDAY AFTERNOON INTO THE OVERNIGHT THERE MAY NOT BE MUCH GOING ON ACROSS OUR AREA. GOING WITH HIGHS IN THE 70S BOTH WEDNESDAY AND THURSDAY...BUT THIS AGAIN DEPENDENT ON CLOUD COVER. AREAS THAT SEE SUN COULD REACH THE 80S BOTH DAYS...WHILE 60S ARE A POSSIBILITY WHERE CLOUDS HOLD TOUGH. / THE PERSISTENT UPPER LOW OVER THE WESTERN UNITED STATES FINALLY LIFTS NORTHEASTWARD TOWARD ND AND MN LATE THIS WEEK AND THROUGH THE WEEKEND. THIS MEANS QUIETER WEATHER FOR OUR AREA. ALTHOUGH ONE CANNOT RULE OUT A FEW SHOWERS OR ISOLATED THUNDERSTORMS IN OUR FORECAST AREA FRIDAY AND SATURDAY...THE CHANCES OF ANY ONE LOCATION GETTING A WETTING RAIN IS FAIRLY REMOTE. DRY WEATHER LOOKS TO PREVAIL ON SUNDAY AND MONDAY. IN RESPONSE TO THE UPPER LOW LIFTING CLOSER TO THE CANADIAN BORDER...COOL SURFACE HIGH PRESSURE WILL THEN FILTER DOWN PROMISING MUCH BELOW NORMAL TEMPERATURES FOR THE WEEKEND. ON FRIDAY AND MONDAY...70S SHOULD BE MORE WIDESPREAD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 622 PM CDT MON MAY 27 2013 TAF SITES HON/FSD/SUX ON THE EDGE OF MVFR/IFR STRATUS THIS EVENING. STRATUS SHOULD EXPAND AND ADVECT EAST ACROSS THE REGION THIS MID TO LATE EVENING. THUNDERSTORM COMPLEXES ARE EXPECTED TO PUSH THROUGH THE REGION AGAIN TONIGHT MAINLY AFTER 05Z AND ENDING BEFORE 12Z. SOME STORMS MAY BE STRONG AND REDUCED CONDITIONS TO IFR AT TIMES. AREAS OF LOW STRATUS AND SOME HAZE/LIGHT FOG WILL PERSIST THROUGH EARLY MORNING TUESDAY. VFR CONDITIONS ARE THEN EXPECTED TO PREVAIL BY MID MORNING TUESDAY AND THROUGH THE DAY. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR SDZ067-070-071. MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ071-072- 080-081-089-090-097-098. IA...FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR IAZ001>003- 012>014-020>022-031-032. DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ001>003- 012>014. NE...FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR NEZ013-014. && $$ SHORT TERM...CHENARD LONG TERM...CHENARD/MJF AVIATION...
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.

MADE SOME MAJOR CHANGES TO POPS THIS EVENING AND OVERNIGHT BASED ON LATEST HRRR AND RUC. NEWEST GUIDANCE SUGGESTS THE LINE OF TSTORMS CURRENTLY WEST RIVER WILL HAVE A VERY DIFFICULT TIME PROGRESSING EASTWARD THIS EVENING. KEPT EVERYTHING EAST OF THE JAMES VALLEY DRY WITH ONLY SLIGHT CHANCES AFTER MIDNIGHT IN THE JAMES VALLEY ITSELF. ALSO LOWERED THE CHANCES OF STORMS BETWEEN THE MISSOURI RIVER AND THE JAMES RIVER FOR THE NEXT FEW HOURS. OTHERWISE FORECAST LOOKS ALRIGHT AND NO FURTHER CHANGES WERE MADE. && .PREVIOUS DISCUSSION... .SHORT TERM...TODAY THROUGH TUESDAY TONIGHT THE POTENTIAL FOR SEVERE STORMS THROUGH THE SHORT TERM WILL BE THE MAIN FORECAST CHALLENGE. A STRONG SHORT WAVE CURRENTLY OVER NORTHERN WYOMING IS PRODUCING SCT THUNDERSTORMS OVER NW SOUTH DAKOTA. THESE STORMS ARE HAVING A DIFFICULT TIME MOVING EASTWARD DUE TO A STABLE ENVIRONMENT WITH LITTLE INSTABILITY AND 0-6KM BULK SHEAR VALUES. BASED ON SEVERAL HI-RES MODELS...IT SEEMS HIGHLY UNLIKELY CONVECTION WILL REACH THE MISSOURI RIVER BEFORE 0Z...MAY PERHAPS THE JAMES RIVER CLOSER TO 6Z. GENERALLY EXPECTING A SLOW MOVING LINE OF SHOWERS WITH A FEW EMBEDDED STRONGER STORM CELL. LOCALLY HEAVY RAINFALL WILL BE THE MAIN THREAT ALONG WITH GUSTY WINDS AND SMALL HAIL. CONVECTION SHOULD CLEAR THE CWA SHORTY AFTER 12Z TUESDAY WITH MOSTLY DRY CONDITIONS PREVAILING THROUGH THE REST OF THE DAY. THAT SAID...A WEAK FRONTAL BOUNDARY SLIDING ACROSS THE REGION AROUND PEAK HEATING COULD PRODUCE A FEW SHOWERS AND THUNDERSTORMS. WHILE CAPE VALUES ARE FAIRLY GOOD AHEAD OF THE FRONT...LIMITED UPPER LEVEL LIFT AND SHEAR IS LACKING SO STRONG STORMS APPEAR UNLIKELY. INCREASING LLM VIA SOUTHERLY FLOW FROM THE CENTRAL PLAINS WILL DEVELOP TUESDAY NIGHT. A FEW MODELS ARE SUGGESTING THE LOW LEVEL WINDS WILL VEER BACKWARD TOWARDS THE BLACK HILLS REGION WHERE UP- SLOPE CONVECTION WILL BE POSSIBLE. OTHERWISE WOULD EXPECT MOST OF THIS CWA WILL SEE DRY CONDITIONS ON TUESDAY NIGHT. .LONG TERM...WEDNESDAY THROUGH MONDAY THE MODELS CONTINUE TO AGREE WELL TO BEGIN THE LONG TERM AND THEN DIVERGE SOME THROUGH MID AND LATE IN THE LONG TERM. A STRONGLY NEGATIVELY TILTED UPPER LEVEL LOW PRESSURE TROUGH IN THE SOUTHWEST US IS STILL ON SCHEDULE TO MAKE ITS WAY INTO THE NORTHERN PLAINS THROUGH WEDNESDAY NIGHT AND EARLY THURSDAY. AS IT DOES...THE TROUGH WILL CLOSE OFF OVER THE REGION THURSDAY. THE MODELS DISAGREE ON THE LOCATION OF CENTER OF THE UPPER LEVEL LOW PRESSURE CIRCULATION AND SUBSEQUENT TRACKING EAST AND SOUTHEAST FRIDAY NIGHT THROUGH SATURDAY. WITH LARGE BROAD SCALE LIFT IN ADVANCE OF THIS UPPER TROUGH ON WEDNESDAY AND WEDNESDAY NIGHT ALONG WITH A GOOD WARM FRONT SURGING NORTHWARD ACROSS OUR REGION...EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS ALL OF THE REGION. EVERYTHING WILL BE IN PLACE FOR SOME SEVERE WEATHER DEVELOPMENT WEDNESDAY AND WEDNESDAY EVENING WITH A STRONG LLJ ALONG WITH DEEP LAYER SHEAR AND INSTABILITY. IF CONVECTION DEVELOPS EARLY AND IS WIDESPREAD...SEVERE WEATHER MAY BE MORE LIMITED. HAVE IN GOOD CHANCES FOR WEDNESDAY AND WEDNESDAY NIGHT. DEPENDING ON WHERE THE SURFACE LOW PRESSURE AREA DEVELOPS AND TRACKS ALONG WITH THE SURFACE DRY LINE/COLD FRONT...THURSDAY MAY ALSO HAVE SOME SEVERE WEATHER MAINLY EAST IN THE CWA. OTHERWISE...KEPT CHANCES OF SHOWERS AND STORMS IN THROUGH SATURDAY BEFORE DRYING IT OUT SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH ANOTHER CHANCE BACK IN THE FORECAST FOR MONDAY. TEMPERATURES SHOULD BE NEAR TO ABOVE NORMAL FOR WEDNESDAY AND THURSDAY BEFORE COOLING BACK TO NEAR TO BELOW NORMAL FOR FRIDAY THROUGH SUNDAY WITH NORTHERLY SURFACE WINDS. MONDAY SHOULD WARM BACK UP WITH MORE SUNSHINE WITH THE AFFECTS OF UPPER LEVEL TROUGHING COMING IN FROM THE WEST BRINGING THE CHANCE OF RAINFALL. && .AVIATION... 06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS EXPECT CEILINGS TO LOWER AGAIN AFTER MIDNIGHT AT MBG AND ABR. EXPECTING IFR CEILINGS ALONG WITH SOME FOG AT ABR...ATY AND PIR AGAIN TONIGHT AND TUESDAY MORNING AS LOW LEVEL MOISTURE REMAINS HIGH. OTHERWISE...A SHORT WAVE TROUGH LIFTING ACROSS THE WESTERN PART OF THE REGION WILL BRING SOME SHOWERS TO MOST OF THE AREA. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...DORN SHORT TERM...SD LONG TERM...MOHR AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
330 PM CDT TUE MAY 28 2013 .SHORT TERM... ANALYSIS OF THE 12Z RAOB DATA INDICATED A BROAD TROUGH OVER THE WESTERN CONUS WITH A MODEST 70KT H25 JET STREAK DOWNSTREAM. A QUASI STATIONARY FRONT WAS DRAPED ACROSS THE PLAINS...ARCING SOUTHWEST TO THE OK PANHANDLE WITH A DRYLINE DROPPING SOUTH FROM A TRIPLE POINT IN SOUTHWEST KS. A DEEP PLUME OF LOWER TROPOSPHERIC MOISTURE WAS FOUND IN THE WARM SECTOR JUST TO THE EAST OF THE DRYLINE FROM THE BIG BEND INTO THE OHIO VALLEY. STRONG MID LEVEL WARM ADVECTION HAS ENHANCED H85-H7 FRONTOGENESIS...RESULTING IN ELEVATED CONVECTION ACROSS WEST CENTRAL TX. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE PERSISTED ALL DAY ACROSS PORTIONS OF THE CONCHO VALLEY AND BIG COUNTRY...SUPPRESSING DIURNAL HEATING AND CAPPING OFF THE STRONG INSTABILITY THAT EXISTS ACROSS THE REGION. TEMPS HAVE STRUGGLED TO REACH 80 DEGREES ACROSS THE NORTH AND WEST BUT DEWPOINTS HAVE BEEN MAINTAINED IN THE MID 60S AREAWIDE. THE BIG QUESTION IS HOW THIS DAYTIME CONVECTION WILL AFFECT THE POTENTIAL FOR ADDITIONAL SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. THE 19Z RAP-BASED MESOANALYSIS INDICATES MLCAPE VALUES APPROACHING 4000 J/KG /WITH CINH ALL BUT GONE/ ACROSS THE WESTERN TIER WHERE WERE HAVE MANAGED TO SEE A LITTLE SUN. THIS MAY BE A LITTLE OVERDONE WHEN COMPARED TO THE EXPERIMENTAL ESRL RAP VERSION AS WELL AS THE NAM POINT SOUNDINGS WHICH SHOW SIGNIFICANTLY MORE CINH STILL PRESENT. I DO ANTICIPATE ADDITIONAL SURFACE BASED STORMS FIRING TO THE WEST OF THE CWA THIS AFTERNOON BUT THEY WILL HAVE TO CONTEND WITH THE CAPPING INVERSION AS THEY MOVE EAST. THIS SHOULD KEEP THE GREATEST POTENTIAL FOR SEVERE CONVECTION ACROSS THE NORTHWEST 1/3 OF THE CWA WITH MAINLY SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE ACROSS THE REMAINDER OF THE AREA. WITH A STOUT LOW LEVEL JET AND AT LEAST SOME LARGE SCALE ASCENT EXPECTED TONIGHT...WE MAY SEE SHOWERS AND THUNDERSTORMS LINGER THROUGH THE OVERNIGHT HOURS. I EXPECT MIN TEMPS NEAR PERSISTENCE WITH MOST AREAS WITHIN A DEGREE OR TWO OF 70. WEDNESDAY/S CONVECTIVE FORECAST IS QUITE TRICKY...DEPENDING ON WHETHER OR NOT WE SEE NOCTURNAL CONVECTION LASTING INTO THE MORNING HOURS. SUBSTANTIAL SYNOPTIC SCALE FORCING WILL HELP ERODE ANY CAP AND WE MAY SEE RATHER JUNKY...DISORGANIZED CONVECTION DEVELOP EARLY IN THE DAY. IF THE CAP HOLDS UNTIL MID AFTERNOON...THE POTENTIAL FOR SEVERE WEATHER WILL INCREASE SIGNIFICANTLY. FORECAST MLCAPE VALUES IN THE NEIGHBORHOOD OF 2000 J/KG AND 35+ KTS OF DEEP LAYER SHEAR WOULD SUPPORT ORGANIZED CONVECTION WITH THE GREATEST THREAT EXISTING ACROSS THE BIG COUNTRY. THERE IS STILL A LOT OF UNCERTAINTY AT THIS TIME AND I HAVE CONTINUED CHANCE POPS ACROSS THE NORTH THROUGH THE AFTERNOON HOURS. MAX TEMPS ARE EXPECTED TO BE IN THE MID 80S. JOHNSON .LONG TERM... BY TOMORROW EVENING THE UPPER LOW WILL BE OVER THE NORTHERN ROCKIES WITH THE ASSOCIATED TROUGH TRAILING SOUTHEAST INTO TEXAS. ANY LINGERING SHOWERS AND THUNDERSTORMS OVER OUR AREA WILL BE ENDING FROM THE WEST TOMORROW EVENING...AND SHOULD BE OUT OF THE AREA BY THURSDAY MORNING. THE UPPER LOW WILL CONTINUE TO DEEPEN AS IT MOVES THROUGH THE CENTRAL PLAINS THIS WEEKEND AND WILL PUSH A COLD FRONT THROUGH THE PANHANDLE ON SATURDAY MORNING AND THROUGH MOST OF THE CWA SATURDAY NIGHT...BEFORE STALLING IN THE VICINITY OF THE INTERSTATE 10 CORRIDOR. THIS FRONTAL BOUNDARY WILL GIVE US OUR NEXT CHANCE FOR RAINFALL WITH A CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE NORTHERN CWA DURING THE DAY ON SATURDAY WITH CHANCES INCREASING LATE SATURDAY AND INTO SATURDAY NIGHT OVER THE ENTIRE FORECAST AREA AS THE FRONT CONTINUES TO MOVE SOUTH BEFORE STALLING SUNDAY MORNING. SHOULD SEE SOME GOOD PREFRONTAL WARMING THURSDAY AND FRIDAY WITH AFTERNOON HIGHS IN THE LOWER TO UPPER 90S BOTH DAYS. SUNDAY HIGHS WILL BE IN THE MID 80S...WARMING BACK INTO THE 90S ON MONDAY. MORNING LOWS IN THE LOW TO MID 70S FRIDAY WILL COOL INTO THE 60S BY SUNDAY MORNING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 71 85 68 94 73 / 30 30 30 10 5 SAN ANGELO 71 86 70 94 74 / 20 20 20 10 5 JUNCTION 71 85 66 92 71 / 20 20 20 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 15
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1247 PM CDT TUE MAY 28 2013 .AVIATION... BREEZY SOUTH WINDS WILL CONTINUE THIS AFTERNOON AT KLBB AND KCDS. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE DRYLINE...IMPACTING KLBB BY AROUND 21Z AND KCDS NEAR THE 23Z TIME FRAME AS ACTIVITY MOVES EAST/NORTHEAST. INSERTED MVFR CEILINGS AND VCTS AT THESE RESPECTIVE TIMES...LIFTING CONDITIONS BACK TO VFR BY 03Z AT KLBB AND 04Z AT KCDS. WILL LIKELY SEE SOME LOW STRATUS TONIGHT AND EARLY WEDNESDAY MORNING...BUT LOCATION AND INTENSITY WILL DEPEND ON RAINFALL AMOUNTS THIS AFTERNOON AND EVENING. && .PREV DISCUSSION... /ISSUED 1154 AM CDT TUE MAY 28 2013/ UPDATE... SEVERE WEATHER THREAT STILL ON TAP FOR THIS AFTERNOON INTO THIS EVENING ACROSS MUCH OF THE EXTREME SOUTHERN TEXAS PANHANDLE...SOUTH PLAINS...AND ROLLING PLAINS. ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE PERMIAN BASIN CONTINUE LATE THIS MORNING AHEAD OF A SLOT OF MID-UPPER LEVEL DRYING PUSHING INTO SOUTHEASTERN NEW MEXICO DOWNSTREAM OF A SHORTWAVE TROUGH MOVING INTO CENTRAL ARIZONA...BUT TRENDS HAVE BEEN FOR THESE CELLS TO DECREASE IN INTENSITY FARTHER NORTHEAST INTO THE ROLLING PLAINS AS THEY LOSE THEIR SOURCE OF LIFT. CURRENT SATELLITE IMAGERY DEPICTS AN EXPANSIVE AREA OF CLOUD COVER EAST OF A TULIA TO TATUM LINE. SURFACE OBSERVATIONS INDICATE WIND FIELDS ARE REMAINING BACKED ACROSS MUCH OF THE CAPROCK...MOST NOTABLY FARTHER SOUTH INTO THE SOUTHERN SOUTH PLAINS. LEE TROUGHING EXTENDING INTO EASTERN NEW MEXICO SHOULD ALLOW THE DRYLINE TO HOLD ON THE CAPROCK THIS AFTERNOON. EXPECT CONVECTIVE INITIATION TO OCCUR BY MID AFTERNOON ALONG AN APPROXIMATE TULIA TO BROWNFIELD LINE. DISCRETE CELLS SHOULD DEVELOP INITIALLY GIVEN 30-40 KNOTS OF 0-6 KM BULK SHEAR BEFORE CONSOLIDATING INTO A LINE ALONG THE DRYLINE AS DEEP LAYER FORCING INCREASES. LARGE HAIL UP TO TENNIS BALL SIZE WILL BE THE PRIMARY THREAT GIVEN STEEP LAPSE RATES ABOVE THE ELEVATED MIXED LAYER OWING TO AROUND 3000 J/KG OF CAPE. WIND GUSTS TO 60 MPH WILL ALSO BE POSSIBLE ALONG WITH AN ISOLATED TORNADO THREAT THIS EVENING WITH THE ONSET OF THE LOW LEVEL JET PROMOTING INCREASING LOW LEVEL SHEAR PROFILES. PREV DISCUSSION... /ISSUED 354 AM CDT TUE MAY 28 2013/ SHORT TERM... CONSIDERABLE MID AND UPPER LEVEL MOISTURE WAS SPREADING INTO THE AREA FROM THE SOUTHWEST ASSOCIATED WITH A WAVE LIFTING OUT ACROSS THE SOUTHERN HIGH PLAINS THIS AFTERNOON. ONLY ISOLATED THUNDERSTORMS HAVE DEVELOPED THUS FAR WITH THIS WAVE OVER SOUTHWEST TEXAS...WHILE SOLUTIONS REMAIN DECIDEDLY MIXED REGARDING HOW MUCH DEVELOPMENT MAY OCCUR ACROSS THE TEXAS SOUTH PLAINS REGION LATER THIS MORNING. THE LATEST WRF/NAM APPEARS QUITE SHOWERY BY MID MORNING INTO THE AFTERNOON WITH WANING ACTIVITY INTO THE EVENING OWING TO A MORE STABLE ENVIRONMENT...WHILE THE LATEST RAP ON THE OTHER HAND DELAYS THE RELEASE OF CONVECTIVE ENERGY UNTIL AFTER NOON WHEN THUNDERSTORMS EXPLODE ALONG THE SURFACE DRY-LINE FROM THE WESTERN SOUTH PLAINS INTO THE SOUTHERN PANHANDLE. WHAT SEEMS CERTAIN IS THAT THE CLOUDS WILL SPREAD OVER THE AREA HOLDING TEMPERATURES DOWN INTO THE AFTERNOON. ALSO...IT SEEMS PLAUSIBLE THAT AT LEAST LIGHT SHOWERS AND PERHAPS A FEW THUNDERSTORMS WILL SPREAD UP INTO THE AREA LATER IN THE MORNING...THOUGH COVERAGE OF THIS ACTIVITY IS HIGHLY UNCERTAIN. THEREFORE...WE REMAIN LESS CONFIDENT HOW THIS MAY IMPACT REMAINING CONVECTIVE ENERGY LATER TODAY. WE HAVE SOMEWHAT SPLIT BETWEEN THE POSSIBLE CHOICES...HOLDING CHANCES LOW THIS MORNING THOUGH RETAINING MODEST CHANCES FOR SEVERE STORMS THIS AFTERNOON AND EVENING. THE MAXIMUM POTENTIAL ENERGY AND SHEAR PROFILES LATER TODAY CERTAINLY SUGGEST OPPORTUNITY FOR AT LEAST A FEW SUPERCELLS WITH LARGE OR EVEN VERY LARGE HAIL POTENTIAL...WHILE HELICITY LEVELS AND CONVERGENCE ALONG THE DRY-LINE WOULD OFFER ISOLATED TORNADO THREAT AS WELL WITH LIFTED CONDENSATION LEVELS POSSIBLY AS LOW AS 3000-6000 FEET. GIVEN THIS POTENTIAL WITH OUR REDUCED CONFIDENCE...WE THINK IT MAY BE BEST TO LEAN A BIT TOWARDS THE WORSER OUTCOME UNTIL CLARITY IMPROVES. WE INCREASED CHANCES SLIGHTLY TODAY AND TONIGHT...RETAINING SEVERE MENTION DURING THE AFTERNOON AND EVENING. MINOR CHANGES FOR MAJORITY OF GRID FIELDS. RMCQUEEN LONG TERM... WEDNESDAY STILL APPEARS TO HAVE THE POTENTIAL FOR A REGIONAL SEVERE WEATHER OUTBREAK ACROSS THE ROLLING PLAINS INTO THE EASTERN TEXAS PANHANDLE AND OKLAHOMA. THE DRYLINE WILL MIX EAST ON WEDNESDAY BUT UNCERTAINTY REMAINS WITH HOW FAR THE DRYLINE WILL MOVE. THE UPPER LEVEL NEGATIVELY TILTED TROUGH AXIS WILL PASS OVER WEST TEXAS MIDDAY ON WEDNESDAY. UNTIL THIS POINT...WEST TEXAS WILL BE UNDER THE INFLUENCE OF THE FAVORABLE EAST SIDE OF THE TROUGH/UPPER LEVEL JET. ISENTROPIC LIFT WILL BEGIN TO PROVIDE LIFT BEGINNING EARLY IN THE EVENING WITH THE INCREASING LOW LEVEL JET. SURFACE INSTABILITY WILL LIKELY BECOME UNCAPPED IN THE AFTERNOON WITH PROGGED CAPE VALUES CRESTING AT 3000-3500 J/KG. INCREASING DEEP LAYER SHEAR WILL BE SUPPORTIVE OF ROTATING SUPERCELLS. DISCRETE SUPERCELLS WILL LIKELY BE THE FAVORED MODE OF CONVECTION WITH SHEAR VECTORS NEARLY NORMAL TO THE DRYLINE. SUBSIDENCE WILL BEGIN TO SPREAD OVER THE REGION WEDNESDAY NIGHT AS WELL AS ASSOCIATED HEIGHT RISES. THIS WILL PERSIST THROUGH THE DAY ON FRIDAY KEEPING THURSDAY AND FRIDAY MOSTLY DRY. BY LATE ON FRIDAY OR EARLY SATURDAY A COLD FRONT WILL MAKE A RUN AT THE AREA WHICH MAY BRING THE NEXT CHANCE OF SHOWERS AND THUNDERSTORMS. THERE EXISTS A LACK OF CONFIDENCE IN THE MODEL SOLUTIONS AT THE MOMENT IN REGARDS TO WHERE THE FRONT WILL STALL OUT. NONETHELESS...HEAVY RAIN MAY BE A POSSIBILITY WHEREVER THE FRONT DOES BECOME STATIONARY. JDV FIRE WEATHER... A DRYLINE WILL MOVE EAST ON WEDNESDAY AFTERNOON TO THE EDGE OF THE CAPROCK. THIS WILL LEAD TO VERY DRY CONDITIONS ON THE SOUTH PLAINS BOTH AFTERNOONS. DEEP MIXING WILL PRODUCE BREEZY WINDS ON WEDNESDAY AFTERNOON WHICH WILL LEAD TO ELEVATED TO PERHAPS BRIEFLY CRITICAL FIRE WEATHER CONDITIONS. THIS DRYLINE WILL MOVE EVEN FARTHER EAST ON THURSDAY SPAWNING A LARGER CRITICAL AREA ON THURSDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 65 92 58 93 59 / 30 20 0 0 0 TULIA 67 89 59 92 61 / 30 20 10 0 0 PLAINVIEW 67 90 61 94 63 / 30 20 10 0 0 LEVELLAND 68 93 61 95 63 / 30 20 10 0 0 LUBBOCK 68 92 64 95 65 / 30 20 10 0 0 DENVER CITY 68 93 60 96 65 / 30 20 0 0 0 BROWNFIELD 69 93 63 96 64 / 30 20 10 0 0 CHILDRESS 69 86 69 95 70 / 30 40 30 10 10 SPUR 69 88 68 95 69 / 30 30 20 10 10 ASPERMONT 71 87 72 94 71 / 30 40 30 10 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 31
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1225 PM CDT TUE MAY 28 2013 .DISCUSSION... SEE 18Z AVIATION DISCUSSION BELOW. && .AVIATION... MVFR CIGS ARE EXPECTED TO PREVAIL ACROSS ALL TERMINALS THROUGH APPROX 21Z. DAYTIME HEATING WILL PRODUCE ENOUGH MIXING TO LIFT CIGS TO VFR FOR THE REST OF THE AFTERNOON AND INTO THE LATE EVENING HOURS. MVFR CIGS WILL ONCE AGAIN RETURN THE THE AREA AFTER 05Z. THERE IS A POSSIBILITY FOR IFR CIGS TO DEVELOP OVER KSOA BUT CONFIDENCE IS TOO LOW AT THIS TIME TO MENTION. GUSTY SOUTH WINDS WILL DIMINISH ACROSS THE KBBD TERMINAL AFTER 00Z THOUGH WINDS WILL STILL BE ABOVE 10 KNOTS. ELSEWHERE GUSTY SOUTH WINDS ARE EXPECTED TO PERSIST THROUGHOUT THE FORECAST PERIOD. THERE IS A CHANCE OF PRECIPITATION MAINLY ACROSS THE KSOA...KSJT...AND KABI TERMINALS. THOUGH THERE IS UNCERTAINTY SURROUNDING THE POSITION OF THE DRYLINE. FOR THIS REASON I LEFT OUT MENTION OF SHOWERS. && .PREV DISCUSSION... /ISSUED 1056 AM CDT TUE MAY 28 2013/ UPDATE... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO MOVE EAST ACROSS THE BIG COUNTRY AND CONCHO VALLEY THIS MORNING AS THE LOW LEVEL JET INTERACTS WITH A MODERATELY UNSTABLE ENVIRONMENT. THIS ACTIVITY WILL REMAIN GENERALLY WEAK BUT WILL WORK TO KEEP TEMPS IN THE 70S FOR A FEW MORE HOURS. HOW THIS AFFECTS AFTERNOON/EVENING CONVECTION CHANCES REMAINS TO BE SEEN AS SURFACE BASED INSTABILITY WILL BE LIMITED AND THE CAP MAY BE DIFFICULT TO OVERCOME. THAT SAID...IF WE GET A FEW HOURS OF HEATING...IT SHOULD NOT BE THAT BIG OF AN ISSUE. THIS WOULD PUT THE GREATEST THREAT FOR DIURNAL CONVECTION OVER THE CONCHO VALLEY AND EDWARDS PLATEAU WHERE THE GREATEST HEATING IS EXPECTED TO OCCUR. WILL CONTINUE TO WATCH THE RADAR TRENDS THROUGHOUT THE DAY AS THIS SITUATION EVOLVES. THE FORECAST HAS BEEN UPDATED TO LOWER MAX TEMPS AND EXPAND POPS FARTHER EAST. OTHERWISE...MOST CHANGES WERE RELATIVELY MINOR. JOHNSON PREV DISCUSSION... /ISSUED 645 AM CDT TUE MAY 28 2013/ DISCUSSION... SEE 12Z AVIATION DISCUSSION BELOW. AVIATION... STRATUS HAS BEEN RATHER SPORADIC THIS MORNING DUE TO ABUNDANT HIGH CLOUDS STREAMING IN FROM THE SOUTHWEST. WILL HANDLE MVFR CIGS WITH TEMPO GROUPS THIS MORNING WITH PREDOMINANT VFR EXPECTED ACROSS THE TERMINALS BY AFTERNOON. WIDELY SCATTERED CONVECTION HAS FORMED WEST OF THE AREA THE PAST COUPLE OF HOURS. THE MOST LIKELY TERMINAL TO BE AFFECT BY THIS ACTIVITY IS KSJT AND HAVE INCLUDED A TEMPO GROUP FOR THUNDER UNTIL 14Z. ADDITIONAL THUNDERSTORMS ARE EXPECTED TO DEVELOP WEST OF THE TERMINALS LATE THIS AFTERNOON WITH ACTIVITY POSSIBLY SPREADING ACROSS THE AREA THIS EVENING. NORTHERN TERMINALS HAVE THE BEST CHANCE TO SEE CONVECTION BUT DUE TO TIMING AND COVERAGE UNCERTAINTY WILL NOT MENTION AT THIS TIME. MVFR CIGS RETURN TO THE TERMINALS LATE TONIGHT INTO THURSDAY MORNING. PREV DISCUSSION... /ISSUED 544 AM CDT TUE MAY 28 2013/ UPDATE... FORECAST WAS UPDATED TO ADD POPS THIS MORNING. DISCUSSION... ELEVATED CONVECTION HAS FORMED OVER THE TRANS PECOS REGION EARLY THIS MORNING...MOST LIKELY DUE TO AN EMBEDDED DISTURBANCE IN THE FLOW ALOFT. LATEST HRRR SEEMS TO HAVE THE BEST HANDLE ON THIS ACTIVITY AND EXPANDS IT AS IT MOVES NORTHEAST ACROSS THE AREA THROUGH THE MORNING HOURS. SHOULD SEE A WEAKENING TREND THOUGH BUT DID ADD MENTIONABLE POPS THIS MORNING MAINLY WEST OF A THROCKMORTON...TO MILLERSVIEW...TO OZONA LINE. NO OTHER CHANGES WERE MADE. PREV DISCUSSION... /ISSUED 359 AM CDT TUE MAY 28 2013/ SHORT TERM... THROUGH TONIGHT.. THE MAIN CONCERN IN THE SHORT TERM PERIOD WILL BE THUNDERSTORM CHANCES AND THE POSSIBILITY OF A FEW STRONG TO SEVERE STORMS MAINLY ACROSS WESTERN SECTIONS THIS EVENING AND OVERNIGHT. AN UPPER TROUGH CURRENTLY CROSSING THE GREAT BASIN REGION WILL AMPLIFY ACROSS THE CENTRAL AND SOUTHERN ROCKIES LATER TODAY. LEE SURFACE LOW WILL RESULT IN A TIGHTENING PRESSURE GRADIENT AGAIN TODAY WITH GUSTY SOUTH WINDS CONTINUING. MUCH LIKE YESTERDAY...LOW CLOUDS WILL OVERSPREAD MUCH OF THE AREA BY DAYBREAK BUT SHOULD BEGIN TO SCATTER OUT BY LATE MORNING. THE DRYLINE WILL SETUP ACROSS FAR WEST TEXAS THIS AFTERNOON AND WILL AGAIN BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT. STORMS THAT DEVELOP WILL LIKELY BECOME SEVERE GIVEN MODERATE INSTABILITY AND ADEQUATE DEEP LAYER SHEAR. CURRENT THINKING IS THAT MOST OF THIS ACTIVITY WILL REMAIN WEST OF THE AREA THROUGH LATE AFTERNOON BUT WILL PROPAGATE NORTHEAST TOWARDS OUR WESTERN COUNTIES DURING THE EVENING HOURS. ADDITIONAL STORMS MAY DEVELOP ALONG THE RETREATING DRYLINE THIS EVENING AND MOVE TOWARDS THE AREA DURING THE OVERNIGHT PERIOD. HIGHEST POPS WERE ORIENTED NORTH AND WEST OF A HASKEL...TO SAN ANGELO...TO OZONA LINE THIS EVENING AND OVERNIGHT. THE MAIN SEVERE WEATHER HAZARDS WILL BE LARGE HAIL AND DAMAGING STRAIGHT LINE WINDS. HIGH TEMPERATURES TODAY WILL BE MAINLY IN THE UPPER 80S WITH LOWS TONIGHT IN THE LOWER 70S. 24 LONG TERM... THE MAIN HIGHLIGHTS IN THE EXTENDED FORECAST ARE A CHANCE OF SEVERE WEATHER ACROSS MUCH OF THE AREA WEDNESDAY...FOLLOWED BY INCREASING RAIN CHANCES THIS WEEKEND WITH A COLD FRONT. A LARGE UPPER LEVEL TROUGH WILL BE APPROACHING WEST CENTRAL TEXAS WEDNESDAY. ALTHOUGH A FEW STORMS COULD BE ONGOING DURING THE EARLY MORNING HOURS...FROM ANY OVERNIGHT CONVECTION ...I BELIEVE THAT MOST OF THE CONVECTION ON WEDNESDAY WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THE DRYLINE WILL SHARPEN AND MIGRATE TOWARD OUR WESTERN BORDER BY MID AFTERNOON. AS THE UPPER LEVEL TROUGH APPROACHES...LARGE SCALE LIFT WILL AID IN THUNDERSTORM DEVELOPMENT ALONG AND EAST OF THE DRYLINE... ESPECIALLY ACROSS THE BIG COUNTRY. A FAIRLY UNSTABLE ATMOSPHERE COMBINED WITH 0-6 KM BULK SHEAR VALUES BETWEEN 35 AND 50 KNOTS...MAY RESULT IN A FEW STRONG TO SEVERE THUNDERSTORMS... ESPECIALLY ACROSS THE BIG COUNTRY. ALTHOUGH LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN CONCERNS...AN ISOLATED TORNADO CANNOT BE RULED OUT. CONVECTION SHOULD CONTINUE INTO THE EVENING HOURS AND MOVE FROM WEST TO EAST...EVENTUALLY MOVING EAST OF THE REGION DURING THE EARLY MORNING HOURS. HIGH TEMPERATURES WILL BE NEAR NORMAL...GENERALLY IN THE MID TO UPPER 80S...WITH LOW TEMPERATURES NEAR 70. DRIER AND WARMER CONDITIONS ARE FORECAST BOTH THURSDAY AND FRIDAY...WITH HIGHS GENERALLY IN THE 90S AND LOWS NEAR 70. MODELS ARE INDICATING THE NEXT UPPER LEVEL LOW/TROUGH MOVING ACROSS THE NORTHERN AND CENTRAL PLAINS LATE FRIDAY AND SATURDAY. THIS WILL SEND A LATE SEASON COLD FRONT INTO WEST CENTRAL TEXAS LATE SATURDAY OR EARLY SUNDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN ASSOCIATION WITH THE FRONT...MAINLY LATE SATURDAY TROUGH SUNDAY. SLOW MOVING...LATE SEASON COLD FRONTS LIKE THIS ONE HAVE HAD A HISTORY OF PRODUCING MUCH NEEDED RAINFALL ACROSS WEST CENTRAL TEXAS. IT IS A BIT TOO EARLY TO DECIPHER EXACTLY WHERE THE FRONT WILL STALL...AND HOW MUCH CONVECTION WILL DEVELOP...BUT THE DETAILS SHOULD BECOME MORE CLEAR IN THE NEXT COUPLE OF DAYS. DANIELS && .PRELIMINARY POINT TEMPS/POPS... ABILENE 86 71 85 71 91 / 30 30 30 30 10 SAN ANGELO 88 72 88 70 94 / 20 20 30 20 10 JUNCTION 86 73 85 72 90 / 10 20 20 20 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/18
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1154 AM CDT TUE MAY 28 2013 .UPDATE... SEVERE WEATHER THREAT STILL ON TAP FOR THIS AFTERNOON INTO THIS EVENING ACROSS MUCH OF THE EXTREME SOUTHERN TEXAS PANHANDLE...SOUTH PLAINS...AND ROLLING PLAINS. ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE PERMIAN BASIN CONTINUE LATE THIS MORNING AHEAD OF A SLOT OF MID-UPPER LEVEL DRYING PUSHING INTO SOUTHEASTERN NEW MEXICO DOWNSTREAM OF A SHORTWAVE TROUGH MOVING INTO CENTRAL ARIZONA...BUT TRENDS HAVE BEEN FOR THESE CELLS TO DECREASE IN INTENSITY FARTHER NORTHEAST INTO THE ROLLING PLAINS AS THEY LOSE THEIR SOURCE OF LIFT. CURRENT SATELLITE IMAGERY DEPICTS AN EXPANSIVE AREA OF CLOUD COVER EAST OF A TULIA TO TATUM LINE. SURFACE OBSERVATIONS INDICATE WIND FIELDS ARE REMAINING BACKED ACROSS MUCH OF THE CAPROCK...MOST NOTABLY FARTHER SOUTH INTO THE SOUTHERN SOUTH PLAINS. LEE TROUGHING EXTENDING INTO EASTERN NEW MEXICO SHOULD ALLOW THE DRYLINE TO HOLD ON THE CAPROCK THIS AFTERNOON. EXPECT CONVECTIVE INITIATION TO OCCUR BY MID AFTERNOON ALONG AN APPROXIMATE TULIA TO BROWNFIELD LINE. DISCRETE CELLS SHOULD DEVELOP INITIALLY GIVEN 30-40 KNOTS OF 0-6 KM BULK SHEAR BEFORE CONSOLIDATING INTO A LINE ALONG THE DRYLINE AS DEEP LAYER FORCING INCREASES. LARGE HAIL UP TO TENNIS BALL SIZE WILL BE THE PRIMARY THREAT GIVEN STEEP LAPSE RATES ABOVE THE ELEVATED MIXED LAYER OWING TO AROUND 3000 J/KG OF CAPE. WIND GUSTS TO 60 MPH WILL ALSO BE POSSIBLE ALONG WITH AN ISOLATED TORNADO THREAT THIS EVENING WITH THE ONSET OF THE LOW LEVEL JET PROMOTING INCREASING LOW LEVEL SHEAR PROFILES. && .PREV DISCUSSION... /ISSUED 712 AM CDT TUE MAY 28 2013/ AVIATION... INITIAL SHOWERS SPREADING NORTHEAST THROUGH PERMIAN BASIN SEEM UNLIKELY TO SPREAD INTO EITHER TAF SITE...AT LEAST NEXT FEW HOURS. SHOULD THESE SHOWERS STAY AWAY...THE CHANCES FOR STRONG OR SEVERE THUNDERSTORMS WOULD INCREASE LATER THIS AFTERNOON AND EVENING. LATEST TAF PACKAGE BASICALLY FOLLOWS THIS PLAN RETAINING BEST THUNDER CHANCES FOR LATE IN THE DAY. A NEAR MVFR STRATUS LAYER IS STILL EXPECTED TO SPREAD CLOSE TO KCDS BY LATE MORNING AS WELL... THOUGH CEILING REMAINS DOUBTFUL. LOW LEVEL SOUTH TO SOUTHEAST FLOW WILL STRENGTHEN LATER THIS MORNING AND AFTERNOON. RMCQUEEN PREV DISCUSSION... /ISSUED 354 AM CDT TUE MAY 28 2013/ SHORT TERM... CONSIDERABLE MID AND UPPER LEVEL MOISTURE WAS SPREADING INTO THE AREA FROM THE SOUTHWEST ASSOCIATED WITH A WAVE LIFTING OUT ACROSS THE SOUTHERN HIGH PLAINS THIS AFTERNOON. ONLY ISOLATED THUNDERSTORMS HAVE DEVELOPED THUS FAR WITH THIS WAVE OVER SOUTHWEST TEXAS...WHILE SOLUTIONS REMAIN DECIDEDLY MIXED REGARDING HOW MUCH DEVELOPMENT MAY OCCUR ACROSS THE TEXAS SOUTH PLAINS REGION LATER THIS MORNING. THE LATEST WRF/NAM APPEARS QUITE SHOWERY BY MID MORNING INTO THE AFTERNOON WITH WANING ACTIVITY INTO THE EVENING OWING TO A MORE STABLE ENVIRONMENT...WHILE THE LATEST RAP ON THE OTHER HAND DELAYS THE RELEASE OF CONVECTIVE ENERGY UNTIL AFTER NOON WHEN THUNDERSTORMS EXPLODE ALONG THE SURFACE DRY-LINE FROM THE WESTERN SOUTH PLAINS INTO THE SOUTHERN PANHANDLE. WHAT SEEMS CERTAIN IS THAT THE CLOUDS WILL SPREAD OVER THE AREA HOLDING TEMPERATURES DOWN INTO THE AFTERNOON. ALSO...IT SEEMS PLAUSIBLE THAT AT LEAST LIGHT SHOWERS AND PERHAPS A FEW THUNDERSTORMS WILL SPREAD UP INTO THE AREA LATER IN THE MORNING...THOUGH COVERAGE OF THIS ACTIVITY IS HIGHLY UNCERTAIN. THEREFORE...WE REMAIN LESS CONFIDENT HOW THIS MAY IMPACT REMAINING CONVECTIVE ENERGY LATER TODAY. WE HAVE SOMEWHAT SPLIT BETWEEN THE POSSIBLE CHOICES...HOLDING CHANCES LOW THIS MORNING THOUGH RETAINING MODEST CHANCES FOR SEVERE STORMS THIS AFTERNOON AND EVENING. THE MAXIMUM POTENTIAL ENERGY AND SHEAR PROFILES LATER TODAY CERTAINLY SUGGEST OPPORTUNITY FOR AT LEAST A FEW SUPERCELLS WITH LARGE OR EVEN VERY LARGE HAIL POTENTIAL...WHILE HELICITY LEVELS AND CONVERGENCE ALONG THE DRY-LINE WOULD OFFER ISOLATED TORNADO THREAT AS WELL WITH LIFTED CONDENSATION LEVELS POSSIBLY AS LOW AS 3000-6000 FEET. GIVEN THIS POTENTIAL WITH OUR REDUCED CONFIDENCE...WE THINK IT MAY BE BEST TO LEAN A BIT TOWARDS THE WORSER OUTCOME UNTIL CLARITY IMPROVES. WE INCREASED CHANCES SLIGHTLY TODAY AND TONIGHT...RETAINING SEVERE MENTION DURING THE AFTERNOON AND EVENING. MINOR CHANGES FOR MAJORITY OF GRID FIELDS. RMCQUEEN LONG TERM... WEDNESDAY STILL APPEARS TO HAVE THE POTENTIAL FOR A REGIONAL SEVERE WEATHER OUTBREAK ACROSS THE ROLLING PLAINS INTO THE EASTERN TEXAS PANHANDLE AND OKLAHOMA. THE DRYLINE WILL MIX EAST ON WEDNESDAY BUT UNCERTAINTY REMAINS WITH HOW FAR THE DRYLINE WILL MOVE. THE UPPER LEVEL NEGATIVELY TILTED TROUGH AXIS WILL PASS OVER WEST TEXAS MIDDAY ON WEDNESDAY. UNTIL THIS POINT...WEST TEXAS WILL BE UNDER THE INFLUENCE OF THE FAVORABLE EAST SIDE OF THE TROUGH/UPPER LEVEL JET. ISENTROPIC LIFT WILL BEGIN TO PROVIDE LIFT BEGINNING EARLY IN THE EVENING WITH THE INCREASING LOW LEVEL JET. SURFACE INSTABILITY WILL LIKELY BECOME UNCAPPED IN THE AFTERNOON WITH PROGGED CAPE VALUES CRESTING AT 3000-3500 J/KG. INCREASING DEEP LAYER SHEAR WILL BE SUPPORTIVE OF ROTATING SUPERCELLS. DISCRETE SUPERCELLS WILL LIKELY BE THE FAVORED MODE OF CONVECTION WITH SHEAR VECTORS NEARLY NORMAL TO THE DRYLINE. SUBSIDENCE WILL BEGIN TO SPREAD OVER THE REGION WEDNESDAY NIGHT AS WELL AS ASSOCIATED HEIGHT RISES. THIS WILL PERSIST THROUGH THE DAY ON FRIDAY KEEPING THURSDAY AND FRIDAY MOSTLY DRY. BY LATE ON FRIDAY OR EARLY SATURDAY A COLD FRONT WILL MAKE A RUN AT THE AREA WHICH MAY BRING THE NEXT CHANCE OF SHOWERS AND THUNDERSTORMS. THERE EXISTS A LACK OF CONFIDENCE IN THE MODEL SOLUTIONS AT THE MOMENT IN REGARDS TO WHERE THE FRONT WILL STALL OUT. NONETHELESS...HEAVY RAIN MAY BE A POSSIBILITY WHEREVER THE FRONT DOES BECOME STATIONARY. JDV FIRE WEATHER... A DRYLINE WILL MOVE EAST ON WEDNESDAY AFTERNOON TO THE EDGE OF THE CAPROCK. THIS WILL LEAD TO VERY DRY CONDITIONS ON THE SOUTH PLAINS BOTH AFTERNOONS. DEEP MIXING WILL PRODUCE BREEZY WINDS ON WEDNESDAY AFTERNOON WHICH WILL LEAD TO ELEVATED TO PERHAPS BRIEFLY CRITICAL FIRE WEATHER CONDITIONS. THIS DRYLINE WILL MOVE EVEN FARTHER EAST ON THURSDAY SPAWNING A LARGER CRITICAL AREA ON THURSDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 94 65 92 58 93 / 20 30 20 0 0 TULIA 89 67 89 59 92 / 40 30 20 10 0 PLAINVIEW 88 67 90 61 94 / 40 30 20 10 0 LEVELLAND 91 68 93 61 95 / 40 30 20 10 0 LUBBOCK 88 68 92 64 95 / 40 30 20 10 0 DENVER CITY 94 68 93 60 96 / 30 30 20 0 0 BROWNFIELD 91 69 93 63 96 / 40 30 20 10 0 CHILDRESS 87 69 86 69 95 / 40 30 40 30 10 SPUR 87 69 88 68 95 / 40 30 30 20 10 ASPERMONT 86 71 87 72 94 / 40 30 40 30 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 31
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1056 AM CDT TUE MAY 28 2013 .UPDATE... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO MOVE EAST ACROSS THE BIG COUNTRY AND CONCHO VALLEY THIS MORNING AS THE LOW LEVEL JET INTERACTS WITH A MODERATELY UNSTABLE ENVIRONMENT. THIS ACTIVITY WILL REMAIN GENERALLY WEAK BUT WILL WORK TO KEEP TEMPS IN THE 70S FOR A FEW MORE HOURS. HOW THIS AFFECTS AFTERNOON/EVENING CONVECTION CHANCES REMAINS TO BE SEEN AS SURFACE BASED INSTABILITY WILL BE LIMITED AND THE CAP MAY BE DIFFICULT TO OVERCOME. THAT SAID...IF WE GET A FEW HOURS OF HEATING...IT SHOULD NOT BE THAT BIG OF AN ISSUE. THIS WOULD PUT THE GREATEST THREAT FOR DIURNAL CONVECTION OVER THE CONCHO VALLEY AND EDWARDS PLATEAU WHERE THE GREATEST HEATING IS EXPECTED TO OCCUR. WILL CONTINUE TO WATCH THE RADAR TRENDS THROUGHOUT THE DAY AS THIS SITUATION EVOLVES. THE FORECAST HAS BEEN UPDATED TO LOWER MAX TEMPS AND EXPAND POPS FARTHER EAST. OTHERWISE...MOST CHANGES WERE RELATIVELY MINOR. JOHNSON && .PREV DISCUSSION... /ISSUED 645 AM CDT TUE MAY 28 2013/ DISCUSSION... SEE 12Z AVIATION DISCUSSION BELOW. AVIATION... STRATUS HAS BEEN RATHER SPORADIC THIS MORNING DUE TO ABUNDANT HIGH CLOUDS STREAMING IN FROM THE SOUTHWEST. WILL HANDLE MVFR CIGS WITH TEMPO GROUPS THIS MORNING WITH PREDOMINANT VFR EXPECTED ACROSS THE TERMINALS BY AFTERNOON. WIDELY SCATTERED CONVECTION HAS FORMED WEST OF THE AREA THE PAST COUPLE OF HOURS. THE MOST LIKELY TERMINAL TO BE AFFECT BY THIS ACTIVITY IS KSJT AND HAVE INCLUDED A TEMPO GROUP FOR THUNDER UNTIL 14Z. ADDITIONAL THUNDERSTORMS ARE EXPECTED TO DEVELOP WEST OF THE TERMINALS LATE THIS AFTERNOON WITH ACTIVITY POSSIBLY SPREADING ACROSS THE AREA THIS EVENING. NORTHERN TERMINALS HAVE THE BEST CHANCE TO SEE CONVECTION BUT DUE TO TIMING AND COVERAGE UNCERTAINTY WILL NOT MENTION AT THIS TIME. MVFR CIGS RETURN TO THE TERMINALS LATE TONIGHT INTO THURSDAY MORNING. PREV DISCUSSION... /ISSUED 544 AM CDT TUE MAY 28 2013/ UPDATE... FORECAST WAS UPDATED TO ADD POPS THIS MORNING. DISCUSSION... ELEVATED CONVECTION HAS FORMED OVER THE TRANS PECOS REGION EARLY THIS MORNING...MOST LIKELY DUE TO AN EMBEDDED DISTURBANCE IN THE FLOW ALOFT. LATEST HRRR SEEMS TO HAVE THE BEST HANDLE ON THIS ACTIVITY AND EXPANDS IT AS IT MOVES NORTHEAST ACROSS THE AREA THROUGH THE MORNING HOURS. SHOULD SEE A WEAKENING TREND THOUGH BUT DID ADD MENTIONABLE POPS THIS MORNING MAINLY WEST OF A THROCKMORTON...TO MILLERSVIEW...TO OZONA LINE. NO OTHER CHANGES WERE MADE. PREV DISCUSSION... /ISSUED 359 AM CDT TUE MAY 28 2013/ SHORT TERM... THROUGH TONIGHT.. THE MAIN CONCERN IN THE SHORT TERM PERIOD WILL BE THUNDERSTORM CHANCES AND THE POSSIBILITY OF A FEW STRONG TO SEVERE STORMS MAINLY ACROSS WESTERN SECTIONS THIS EVENING AND OVERNIGHT. AN UPPER TROUGH CURRENTLY CROSSING THE GREAT BASIN REGION WILL AMPLIFY ACROSS THE CENTRAL AND SOUTHERN ROCKIES LATER TODAY. LEE SURFACE LOW WILL RESULT IN A TIGHTENING PRESSURE GRADIENT AGAIN TODAY WITH GUSTY SOUTH WINDS CONTINUING. MUCH LIKE YESTERDAY...LOW CLOUDS WILL OVERSPREAD MUCH OF THE AREA BY DAYBREAK BUT SHOULD BEGIN TO SCATTER OUT BY LATE MORNING. THE DRYLINE WILL SETUP ACROSS FAR WEST TEXAS THIS AFTERNOON AND WILL AGAIN BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT. STORMS THAT DEVELOP WILL LIKELY BECOME SEVERE GIVEN MODERATE INSTABILITY AND ADEQUATE DEEP LAYER SHEAR. CURRENT THINKING IS THAT MOST OF THIS ACTIVITY WILL REMAIN WEST OF THE AREA THROUGH LATE AFTERNOON BUT WILL PROPAGATE NORTHEAST TOWARDS OUR WESTERN COUNTIES DURING THE EVENING HOURS. ADDITIONAL STORMS MAY DEVELOP ALONG THE RETREATING DRYLINE THIS EVENING AND MOVE TOWARDS THE AREA DURING THE OVERNIGHT PERIOD. HIGHEST POPS WERE ORIENTED NORTH AND WEST OF A HASKEL...TO SAN ANGELO...TO OZONA LINE THIS EVENING AND OVERNIGHT. THE MAIN SEVERE WEATHER HAZARDS WILL BE LARGE HAIL AND DAMAGING STRAIGHT LINE WINDS. HIGH TEMPERATURES TODAY WILL BE MAINLY IN THE UPPER 80S WITH LOWS TONIGHT IN THE LOWER 70S. 24 LONG TERM... THE MAIN HIGHLIGHTS IN THE EXTENDED FORECAST ARE A CHANCE OF SEVERE WEATHER ACROSS MUCH OF THE AREA WEDNESDAY...FOLLOWED BY INCREASING RAIN CHANCES THIS WEEKEND WITH A COLD FRONT. A LARGE UPPER LEVEL TROUGH WILL BE APPROACHING WEST CENTRAL TEXAS WEDNESDAY. ALTHOUGH A FEW STORMS COULD BE ONGOING DURING THE EARLY MORNING HOURS...FROM ANY OVERNIGHT CONVECTION ...I BELIEVE THAT MOST OF THE CONVECTION ON WEDNESDAY WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THE DRYLINE WILL SHARPEN AND MIGRATE TOWARD OUR WESTERN BORDER BY MID AFTERNOON. AS THE UPPER LEVEL TROUGH APPROACHES...LARGE SCALE LIFT WILL AID IN THUNDERSTORM DEVELOPMENT ALONG AND EAST OF THE DRYLINE... ESPECIALLY ACROSS THE BIG COUNTRY. A FAIRLY UNSTABLE ATMOSPHERE COMBINED WITH 0-6 KM BULK SHEAR VALUES BETWEEN 35 AND 50 KNOTS...MAY RESULT IN A FEW STRONG TO SEVERE THUNDERSTORMS... ESPECIALLY ACROSS THE BIG COUNTRY. ALTHOUGH LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN CONCERNS...AN ISOLATED TORNADO CANNOT BE RULED OUT. CONVECTION SHOULD CONTINUE INTO THE EVENING HOURS AND MOVE FROM WEST TO EAST...EVENTUALLY MOVING EAST OF THE REGION DURING THE EARLY MORNING HOURS. HIGH TEMPERATURES WILL BE NEAR NORMAL...GENERALLY IN THE MID TO UPPER 80S...WITH LOW TEMPERATURES NEAR 70. DRIER AND WARMER CONDITIONS ARE FORECAST BOTH THURSDAY AND FRIDAY...WITH HIGHS GENERALLY IN THE 90S AND LOWS NEAR 70. MODELS ARE INDICATING THE NEXT UPPER LEVEL LOW/TROUGH MOVING ACROSS THE NORTHERN AND CENTRAL PLAINS LATE FRIDAY AND SATURDAY. THIS WILL SEND A LATE SEASON COLD FRONT INTO WEST CENTRAL TEXAS LATE SATURDAY OR EARLY SUNDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN ASSOCIATION WITH THE FRONT...MAINLY LATE SATURDAY TROUGH SUNDAY. SLOW MOVING...LATE SEASON COLD FRONTS LIKE THIS ONE HAVE HAD A HISTORY OF PRODUCING MUCH NEEDED RAINFALL ACROSS WEST CENTRAL TEXAS. IT IS A BIT TOO EARLY TO DECIPHER EXACTLY WHERE THE FRONT WILL STALL...AND HOW MUCH CONVECTION WILL DEVELOP...BUT THE DETAILS SHOULD BECOME MORE CLEAR IN THE NEXT COUPLE OF DAYS. DANIELS && .PRELIMINARY POINT TEMPS/POPS... ABILENE 86 71 85 71 91 / 30 30 30 30 10 SAN ANGELO 88 72 88 70 94 / 20 20 30 20 10 JUNCTION 86 73 85 72 90 / 10 20 20 20 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 25
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
712 AM CDT TUE MAY 28 2013 .AVIATION... INITIAL SHOWERS SPREADING NORTHEAST THROUGH PERMIAN BASIN SEEM UNLIKELY TO SPREAD INTO EITHER TAF SITE...AT LEAST NEXT FEW HOURS. SHOULD THESE SHOWERS STAY AWAY...THE CHANCES FOR STRONG OR SEVERE THUNDERSTORMS WOULD INCREASE LATER THIS AFTERNOON AND EVENING. LATEST TAF PACKAGE BASICALLY FOLLOWS THIS PLAN RETAINING BEST THUNDER CHANCES FOR LATE IN THE DAY. A NEAR MVFR STRATUS LAYER IS STILL EXPECTED TO SPREAD CLOSE TO KCDS BY LATE MORNING AS WELL... THOUGH CEILING REMAINS DOUBTFUL. LOW LEVEL SOUTH TO SOUTHEAST FLOW WILL STRENGTHEN LATER THIS MORNING AND AFTERNOON. RMCQUEEN && .PREV DISCUSSION... /ISSUED 354 AM CDT TUE MAY 28 2013/ SHORT TERM... CONSIDERABLE MID AND UPPER LEVEL MOISTURE WAS SPREADING INTO THE AREA FROM THE SOUTHWEST ASSOCIATED WITH A WAVE LIFTING OUT ACROSS THE SOUTHERN HIGH PLAINS THIS AFTERNOON. ONLY ISOLATED THUNDERSTORMS HAVE DEVELOPED THUS FAR WITH THIS WAVE OVER SOUTHWEST TEXAS...WHILE SOLUTIONS REMAIN DECIDEDLY MIXED REGARDING HOW MUCH DEVELOPMENT MAY OCCUR ACROSS THE TEXAS SOUTH PLAINS REGION LATER THIS MORNING. THE LATEST WRF/NAM APPEARS QUITE SHOWERY BY MID MORNING INTO THE AFTERNOON WITH WANING ACTIVITY INTO THE EVENING OWING TO A MORE STABLE ENVIRONMENT...WHILE THE LATEST RAP ON THE OTHER HAND DELAYS THE RELEASE OF CONVECTIVE ENERGY UNTIL AFTER NOON WHEN THUNDERSTORMS EXPLODE ALONG THE SURFACE DRY-LINE FROM THE WESTERN SOUTH PLAINS INTO THE SOUTHERN PANHANDLE. WHAT SEEMS CERTAIN IS THAT THE CLOUDS WILL SPREAD OVER THE AREA HOLDING TEMPERATURES DOWN INTO THE AFTERNOON. ALSO...IT SEEMS PLAUSIBLE THAT AT LEAST LIGHT SHOWERS AND PERHAPS A FEW THUNDERSTORMS WILL SPREAD UP INTO THE AREA LATER IN THE MORNING...THOUGH COVERAGE OF THIS ACTIVITY IS HIGHLY UNCERTAIN. THEREFORE...WE REMAIN LESS CONFIDENT HOW THIS MAY IMPACT REMAINING CONVECTIVE ENERGY LATER TODAY. WE HAVE SOMEWHAT SPLIT BETWEEN THE POSSIBLE CHOICES...HOLDING CHANCES LOW THIS MORNING THOUGH RETAINING MODEST CHANCES FOR SEVERE STORMS THIS AFTERNOON AND EVENING. THE MAXIMUM POTENTIAL ENERGY AND SHEAR PROFILES LATER TODAY CERTAINLY SUGGEST OPPORTUNITY FOR AT LEAST A FEW SUPERCELLS WITH LARGE OR EVEN VERY LARGE HAIL POTENTIAL...WHILE HELICITY LEVELS AND CONVERGENCE ALONG THE DRY-LINE WOULD OFFER ISOLATED TORNADO THREAT AS WELL WITH LIFTED CONDENSATION LEVELS POSSIBLY AS LOW AS 3000-6000 FEET. GIVEN THIS POTENTIAL WITH OUR REDUCED CONFIDENCE...WE THINK IT MAY BE BEST TO LEAN A BIT TOWARDS THE WORSER OUTCOME UNTIL CLARITY IMPROVES. WE INCREASED CHANCES SLIGHTLY TODAY AND TONIGHT...RETAINING SEVERE MENTION DURING THE AFTERNOON AND EVENING. MINOR CHANGES FOR MAJORITY OF GRID FIELDS. RMCQUEEN LONG TERM... WEDNESDAY STILL APPEARS TO HAVE THE POTENTIAL FOR A REGIONAL SEVERE WEATHER OUTBREAK ACROSS THE ROLLING PLAINS INTO THE EASTERN TEXAS PANHANDLE AND OKLAHOMA. THE DRYLINE WILL MIX EAST ON WEDNESDAY BUT UNCERTAINTY REMAINS WITH HOW FAR THE DRYLINE WILL MOVE. THE UPPER LEVEL NEGATIVELY TILTED TROUGH AXIS WILL PASS OVER WEST TEXAS MIDDAY ON WEDNESDAY. UNTIL THIS POINT...WEST TEXAS WILL BE UNDER THE INFLUENCE OF THE FAVORABLE EAST SIDE OF THE TROUGH/UPPER LEVEL JET. ISENTROPIC LIFT WILL BEGIN TO PROVIDE LIFT BEGINNING EARLY IN THE EVENING WITH THE INCREASING LOW LEVEL JET. SURFACE INSTABILITY WILL LIKELY BECOME UNCAPPED IN THE AFTERNOON WITH PROGGED CAPE VALUES CRESTING AT 3000-3500 J/KG. INCREASING DEEP LAYER SHEAR WILL BE SUPPORTIVE OF ROTATING SUPERCELLS. DISCRETE SUPERCELLS WILL LIKELY BE THE FAVORED MODE OF CONVECTION WITH SHEAR VECTORS NEARLY NORMAL TO THE DRYLINE. SUBSIDENCE WILL BEGIN TO SPREAD OVER THE REGION WEDNESDAY NIGHT AS WELL AS ASSOCIATED HEIGHT RISES. THIS WILL PERSIST THROUGH THE DAY ON FRIDAY KEEPING THURSDAY AND FRIDAY MOSTLY DRY. BY LATE ON FRIDAY OR EARLY SATURDAY A COLD FRONT WILL MAKE A RUN AT THE AREA WHICH MAY BRING THE NEXT CHANCE OF SHOWERS AND THUNDERSTORMS. THERE EXISTS A LACK OF CONFIDENCE IN THE MODEL SOLUTIONS AT THE MOMENT IN REGARDS TO WHERE THE FRONT WILL STALL OUT. NONETHELESS...HEAVY RAIN MAY BE A POSSIBILITY WHEREVER THE FRONT DOES BECOME STATIONARY. JDV FIRE WEATHER... A DRYLINE WILL MOVE EAST ON WEDNESDAY AFTERNOON TO THE EDGE OF THE CAPROCK. THIS WILL LEAD TO VERY DRY CONDITIONS ON THE SOUTH PLAINS BOTH AFTERNOONS. DEEP MIXING WILL PRODUCE BREEZY WINDS ON WEDNESDAY AFTERNOON WHICH WILL LEAD TO ELEVATED TO PERHAPS BRIEFLY CRITICAL FIRE WEATHER CONDITIONS. THIS DRYLINE WILL MOVE EVEN FARTHER EAST ON THURSDAY SPAWNING A LARGER CRITICAL AREA ON THURSDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 92 65 92 58 93 / 20 30 20 0 0 TULIA 89 67 89 59 92 / 40 30 20 10 0 PLAINVIEW 88 67 90 61 94 / 40 30 20 10 0 LEVELLAND 91 68 93 61 95 / 40 30 20 10 0 LUBBOCK 88 68 92 65 95 / 40 30 20 10 0 DENVER CITY 94 68 93 60 96 / 30 30 20 0 0 BROWNFIELD 91 69 93 63 96 / 40 30 20 10 0 CHILDRESS 89 69 86 69 95 / 40 30 40 30 10 SPUR 87 69 88 68 95 / 40 30 30 20 10 ASPERMONT 88 71 87 72 94 / 40 30 40 30 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/05
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
544 AM CDT TUE MAY 28 2013 .UPDATE... FORECAST WAS UPDATED TO ADD POPS THIS MORNING. && .DISCUSSION... ELEVATED CONVECTION HAS FORMED OVER THE TRANS PECOS REGION EARLY THIS MORNING...MOST LIKELY DUE TO AN EMBEDDED DISTURBANCE IN THE FLOW ALOFT. LATEST HRRR SEEMS TO HAVE THE BEST HANDLE ON THIS ACTIVITY AND EXPANDS IT AS IT MOVES NORTHEAST ACROSS THE AREA THROUGH THE MORNING HOURS. SHOULD SEE A WEAKENING TREND THOUGH BUT DID ADD MENTIONABLE POPS THIS MORNING MAINLY WEST OF A THROCKMORTON...TO MILLERSVIEW...TO OZONA LINE. NO OTHER CHANGES WERE MADE. && .PREV DISCUSSION... /ISSUED 359 AM CDT TUE MAY 28 2013/ SHORT TERM... .THROUGH TONIGHT.. THE MAIN CONCERN IN THE SHORT TERM PERIOD WILL BE THUNDERSTORM CHANCES AND THE POSSIBILITY OF A FEW STRONG TO SEVERE STORMS MAINLY ACROSS WESTERN SECTIONS THIS EVENING AND OVERNIGHT. AN UPPER TROUGH CURRENTLY CROSSING THE GREAT BASIN REGION WILL AMPLIFY ACROSS THE CENTRAL AND SOUTHERN ROCKIES LATER TODAY. LEE SURFACE LOW WILL RESULT IN A TIGHTENING PRESSURE GRADIENT AGAIN TODAY WITH GUSTY SOUTH WINDS CONTINUING. MUCH LIKE YESTERDAY...LOW CLOUDS WILL OVERSPREAD MUCH OF THE AREA BY DAYBREAK BUT SHOULD BEGIN TO SCATTER OUT BY LATE MORNING. THE DRYLINE WILL SETUP ACROSS FAR WEST TEXAS THIS AFTERNOON AND WILL AGAIN BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT. STORMS THAT DEVELOP WILL LIKELY BECOME SEVERE GIVEN MODERATE INSTABILITY AND ADEQUATE DEEP LAYER SHEAR. CURRENT THINKING IS THAT MOST OF THIS ACTIVITY WILL REMAIN WEST OF THE AREA THROUGH LATE AFTERNOON BUT WILL PROPAGATE NORTHEAST TOWARDS OUR WESTERN COUNTIES DURING THE EVENING HOURS. ADDITIONAL STORMS MAY DEVELOP ALONG THE RETREATING DRYLINE THIS EVENING AND MOVE TOWARDS THE AREA DURING THE OVERNIGHT PERIOD. HIGHEST POPS WERE ORIENTED NORTH AND WEST OF A HASKEL...TO SAN ANGELO...TO OZONA LINE THIS EVENING AND OVERNIGHT. THE MAIN SEVERE WEATHER HAZARDS WILL BE LARGE HAIL AND DAMAGING STRAIGHT LINE WINDS. HIGH TEMPERATURES TODAY WILL BE MAINLY IN THE UPPER 80S WITH LOWS TONIGHT IN THE LOWER 70S. 24 LONG TERM... THE MAIN HIGHLIGHTS IN THE EXTENDED FORECAST ARE A CHANCE OF SEVERE WEATHER ACROSS MUCH OF THE AREA WEDNESDAY...FOLLOWED BY INCREASING RAIN CHANCES THIS WEEKEND WITH A COLD FRONT. A LARGE UPPER LEVEL TROUGH WILL BE APPROACHING WEST CENTRAL TEXAS WEDNESDAY. ALTHOUGH A FEW STORMS COULD BE ONGOING DURING THE EARLY MORNING HOURS...FROM ANY OVERNIGHT CONVECTION ...I BELIEVE THAT MOST OF THE CONVECTION ON WEDNESDAY WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THE DRYLINE WILL SHARPEN AND MIGRATE TOWARD OUR WESTERN BORDER BY MID AFTERNOON. AS THE UPPER LEVEL TROUGH APPROACHES...LARGE SCALE LIFT WILL AID IN THUNDERSTORM DEVELOPMENT ALONG AND EAST OF THE DRYLINE...ESPECIALLY ACROSS THE BIG COUNTRY. A FAIRLY UNSTABLE ATMOSPHERE COMBINED WITH 0-6 KM BULK SHEAR VALUES BETWEEN 35 AND 50 KNOTS...MAY RESULT IN A FEW STRONG TO SEVERE THUNDERSTORMS...ESPECIALLY ACROSS THE BIG COUNTRY. ALTHOUGH LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN CONCERNS...AN ISOLATED TORNADO CANNOT BE RULED OUT. CONVECTION SHOULD CONTINUE INTO THE EVENING HOURS AND MOVE FROM WEST TO EAST...EVENTUALLY MOVING EAST OF THE REGION DURING THE EARLY MORNING HOURS. HIGH TEMPERATURES WILL BE NEAR NORMAL...GENERALLY IN THE MID TO UPPER 80S...WITH LOW TEMPERATURES NEAR 70. DRIER AND WARMER CONDITIONS ARE FORECAST BOTH THURSDAY AND FRIDAY...WITH HIGHS GENERALLY IN THE 90S AND LOWS NEAR 70. MODELS ARE INDICATING THE NEXT UPPER LEVEL LOW/TROUGH MOVING ACROSS THE NORTHERN AND CENTRAL PLAINS LATE FRIDAY AND SATURDAY. THIS WILL SEND A LATE SEASON COLD FRONT INTO WEST CENTRAL TEXAS LATE SATURDAY OR EARLY SUNDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN ASSOCIATION WITH THE FRONT...MAINLY LATE SATURDAY TROUGH SUNDAY. SLOW MOVING...LATE SEASON COLD FRONTS LIKE THIS ONE HAVE HAD A HISTORY OF PRODUCING MUCH NEEDED RAINFALL ACROSS WEST CENTRAL TEXAS. IT IS A BIT TOO EARLY TO DECIPHER EXACTLY WHERE THE FRONT WILL STALL...AND HOW MUCH CONVECTION WILL DEVELOP...BUT THE DETAILS SHOULD BECOME MORE CLEAR IN THE NEXT COUPLE OF DAYS. DANIELS && .PRELIMINARY POINT TEMPS/POPS... ABILENE 88 71 85 71 91 / 20 30 30 30 10 SAN ANGELO 89 72 88 70 94 / 20 20 30 20 10 JUNCTION 87 73 85 72 90 / 10 20 20 20 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
354 AM CDT TUE MAY 28 2013 .SHORT TERM... CONSIDERABLE MID AND UPPER LEVEL MOISTURE WAS SPREADING INTO THE AREA FROM THE SOUTHWEST ASSOCIATED WITH A WAVE LIFTING OUT ACROSS THE SOUTHERN HIGH PLAINS THIS AFTERNOON. ONLY ISOLATED THUNDERSTORMS HAVE DEVELOPED THUS FAR WITH THIS WAVE OVER SOUTHWEST TEXAS...WHILE SOLUTIONS REMAIN DECIDEDLY MIXED REGARDING HOW MUCH DEVELOPMENT MAY OCCUR ACROSS THE TEXAS SOUTH PLAINS REGION LATER THIS MORNING. THE LATEST WRF/NAM APPEARS QUITE SHOWERY BY MID MORNING INTO THE AFTERNOON WITH WANING ACTIVITY INTO THE EVENING OWING TO A MORE STABLE ENVIRONMENT...WHILE THE LATEST RAP ON THE OTHER HAND DELAYS THE RELEASE OF CONVECTIVE ENERGY UNTIL AFTER NOON WHEN THUNDERSTORMS EXPLODE ALONG THE SURFACE DRY-LINE FROM THE WESTERN SOUTH PLAINS INTO THE SOUTHERN PANHANDLE. WHAT SEEMS CERTAIN IS THAT THE CLOUDS WILL SPREAD OVER THE AREA HOLDING TEMPERATURES DOWN INTO THE AFTERNOON. ALSO...IT SEEMS PLAUSIBLE THAT AT LEAST LIGHT SHOWERS AND PERHAPS A FEW THUNDERSTORMS WILL SPREAD UP INTO THE AREA LATER IN THE MORNING...THOUGH COVERAGE OF THIS ACTIVITY IS HIGHLY UNCERTAIN. THEREFORE...WE REMAIN LESS CONFIDENT HOW THIS MAY IMPACT REMAINING CONVECTIVE ENERGY LATER TODAY. WE HAVE SOMEWHAT SPLIT BETWEEN THE POSSIBLE CHOICES...HOLDING CHANCES LOW THIS MORNING THOUGH RETAINING MODEST CHANCES FOR SEVERE STORMS THIS AFTERNOON AND EVENING. THE MAXIMUM POTENTIAL ENERGY AND SHEAR PROFILES LATER TODAY CERTAINLY SUGGEST OPPORTUNITY FOR AT LEAST A FEW SUPERCELLS WITH LARGE OR EVEN VERY LARGE HAIL POTENTIAL...WHILE HELICITY LEVELS AND CONVERGENCE ALONG THE DRY-LINE WOULD OFFER ISOLATED TORNADO THREAT AS WELL WITH LIFTED CONDENSATION LEVELS POSSIBLY AS LOW AS 3000-6000 FEET. GIVEN THIS POTENTIAL WITH OUR REDUCED CONFIDENCE...WE THINK IT MAY BE BEST TO LEAN A BIT TOWARDS THE WORSER OUTCOME UNTIL CLARITY IMPROVES. WE INCREASED CHANCES SLIGHTLY TODAY AND TONIGHT...RETAINING SEVERE MENTION DURING THE AFTERNOON AND EVENING. MINOR CHANGES FOR MAJORITY OF GRID FIELDS. RMCQUEEN && .LONG TERM... WEDNESDAY STILL APPEARS TO HAVE THE POTENTIAL FOR A REGIONAL SEVERE WEATHER OUTBREAK ACROSS THE ROLLING PLAINS INTO THE EASTERN TEXAS PANHANDLE AND OKLAHOMA. THE DRYLINE WILL MIX EAST ON WEDNESDAY BUT UNCERTAINTY REMAINS WITH HOW FAR THE DRYLINE WILL MOVE. THE UPPER LEVEL NEGATIVELY TILTED TROUGH AXIS WILL PASS OVER WEST TEXAS MIDDAY ON WEDNESDAY. UNTIL THIS POINT...WEST TEXAS WILL BE UNDER THE INFLUENCE OF THE FAVORABLE EAST SIDE OF THE TROUGH/UPPER LEVEL JET. ISENTROPIC LIFT WILL BEGIN TO PROVIDE LIFT BEGINNING EARLY IN THE EVENING WITH THE INCREASING LOW LEVEL JET. SURFACE INSTABILITY WILL LIKELY BECOME UNCAPPED IN THE AFTERNOON WITH PROGGED CAPE VALUES CRESTING AT 3000-3500 J/KG. INCREASING DEEP LAYER SHEAR WILL BE SUPPORTIVE OF ROTATING SUPERCELLS. DISCRETE SUPERCELLS WILL LIKELY BE THE FAVORED MODE OF CONVECTION WITH SHEAR VECTORS NEARLY NORMAL TO THE DRYLINE. SUBSIDENCE WILL BEGIN TO SPREAD OVER THE REGION WEDNESDAY NIGHT AS WELL AS ASSOCIATED HEIGHT RISES. THIS WILL PERSIST THROUGH THE DAY ON FRIDAY KEEPING THURSDAY AND FRIDAY MOSTLY DRY. BY LATE ON FRIDAY OR EARLY SATURDAY A COLD FRONT WILL MAKE A RUN AT THE AREA WHICH MAY BRING THE NEXT CHANCE OF SHOWERS AND THUNDERSTORMS. THERE EXISTS A LACK OF CONFIDENCE IN THE MODEL SOLUTIONS AT THE MOMENT IN REGARDS TO WHERE THE FRONT WILL STALL OUT. NONETHELESS...HEAVY RAIN MAY BE A POSSIBILITY WHEREVER THE FRONT DOES BECOME STATIONARY. JDV && .FIRE WEATHER... A DRYLINE WILL MOVE EAST ON WEDNESDAY AFTERNOON TO THE EDGE OF THE CAPROCK. THIS WILL LEAD TO VERY DRY CONDITIONS ON THE SOUTH PLAINS BOTH AFTERNOONS. DEEP MIXING WILL PRODUCE BREEZY WINDS ON WEDNESDAY AFTERNOON WHICH WILL LEAD TO ELEVATED TO PERHAPS BRIEFLY CRITICAL FIRE WEATHER CONDITIONS. THIS DRYLINE WILL MOVE EVEN FARTHER EAST ON THURSDAY SPAWNING A LARGER CRITICAL AREA ON THURSDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 92 65 92 58 93 / 20 30 20 0 0 TULIA 89 67 89 59 92 / 40 30 20 10 0 PLAINVIEW 88 67 90 61 94 / 40 30 20 10 0 LEVELLAND 91 68 93 61 95 / 40 30 20 10 0 LUBBOCK 88 68 92 64 95 / 40 30 20 10 0 DENVER CITY 94 68 93 60 96 / 30 30 20 0 0 BROWNFIELD 91 69 93 63 96 / 40 30 20 10 0 CHILDRESS 89 69 86 69 95 / 40 30 40 30 10 SPUR 87 69 88 68 95 / 40 30 30 20 10 ASPERMONT 88 71 87 72 94 / 40 30 40 30 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/01
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1245 PM EDT TUE MAY 28 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH THE WEEK WITH ABOVE NORMAL TEMPERATURES AND ISOLATED CHANCES FOR STORMS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1005 AM EDT TUESDAY... MAIN CONCERN WITH POTENTIAL CONVECTIVE COVERAGE THIS AFTERNOON AS THE TAIL OF A FAINT IMPULSE MOVES ACROSS FROM WEST OF THE MOUNTAINS AND COMBINES WITH HEATING AND RETURNING DEEPER MOISTURE. MODIFIED MORNING SOUNDINGS DO SHOW SOME MODEST CAPE OF 1000-1500 J/KG FROM THE BLUE RIDGE EAST ALTHOUGH APPEARS FOCUS LACKING HEADING EAST. LATEST HRRR OUTPUT CONTINUES TO SHOW SHRA/TSRA UNZIPPING ALONG THE BLUE RIDGE FROM SW TO NE AS AIDED BY DIFF HEATING EARLY AND WEAK CONVERGENCE PER LOW LEVEL WINDS BACKING MORE SOUTHERLY LATER ON. SIMILAR DEPICTION FROM THE RNK-WRF AND TO SOME DEGREE THE LATEST NAM SUPPORT AT LEAST A SCATTERING OF POPS BLUE RIDGE AND POINTS NORTH CLOSER TO THE UPPER SUPPORT AND PERHAPS LATER OUTFLOW. WILL KEEP IN SLIGHT POPS ESLW FOR A POP UP STORM OR TWO WITH LEAST COVERAGE SE. ANY SEVERE THREAT WOULD LOOK TO COME FROM PULSE NATURE STORMS IF CONVECTION CAN GET DEEP ENOUGH GIVEN STEEP LAPSES AND LOW WET BULB ZERO VALUES THIS AFTERNOON. MORNING THICKNESS OFF RAOBS SHOW HIGHS WELL INTO THE 70S AND LOWER 80S WEST GIVEN INCREASING INSOLATION AFTER EARLY MID DECK...AND MOSTLY MID 80S EAST AS A DECENT 85H JET MIXES DOWN SOME OF THE INVADING WARMER AIR ALOFT. TONIGHT...ANY CONVECTION WILL GO AWAY AFTER SUNSET WITH SKIES BECOMING MOSTLY CLEAR. WITH HUMIDITY INCREASING THERE MAY BE A BETTER CHANCE FOR FOG IN THE MOUNTAINS AND RIVER VALLEYS...AND WHERE ANY RAIN OCCURS THIS AFTERNOON. LOWS WILL RANGE FROM THE MID 50S OVER THE MOUNTAIN VALLEYS TO LOWER 60S EAST. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM EDT TUESDAY... WILL START WEDNESDAY OUT WITH UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES...WHILE A NEGATIVELY TILTED UPPER LEVEL TROUGH DIGS FROM THE PACIFIC NORTHWEST ALL THE WAY INTO WEST TEXAS. WE MAY SEE A FEW SHOWERS AND THUNDERSTORMS DEVELOP ALONG OUR MOUNTAINS DURING THE AFTERNOON AND EVENING...BUT RIDGING ALOFT WILL KEEP THIS ACTIVITY ISOLATED AND WEAK. RIDGING WILL ALSO ALLOW FOR WARMER AFTERNOON TEMPERATURES...WITH HIGHS RANGING FROM THE UPPER 70S TO THE MID 80S ACROSS THE MOUNTAINS...AND NEAR 90 ACROSS THE PIEDMONTS. THE WEATHER PATTERN WILL REMAIN LITTLE CHANGED THROUGH THE END OF THE WORKWEEK...WITH UPPER LEVEL RIDGING KEEPING PRECIPITATION LIMITED TO ISOLATED SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EVENING FOR THURSDAY AND FRIDAY...MAINLY ACROSS THE MOUNTAINS. HIGHS WILL RANGE FROM THE LOW/MID 80S WEST TO THE LOW 90S EAST...WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOW 60S AREAWIDE. && .LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 333 PM EDT MONDAY... MOST OF THE WEEKEND WILL CONTINUE TO BE HOT AND DRY...WITH DEWPOINTS INCREASING SOMEWHAT DURING THE SECOND HALF OF THE WEEKEND AS A FRONT SLOWS THROUGH THE OHIO VALLEY TRYING TO DISPLACE THE UPPER RIDGE. POSSIBLY BE ABLE TO SQUEAK IN ANOTHER MOSTLY DRY DAY ON SUNDAY WITH MOST SHOWERS AND STORMS ARRIVING SUNDAY NIGHT AND MONDAY...FOLLOWING THE 12Z ECMWF TIMING. MOST OF THE SUPPORT FOR THIS BOUNDARY WILL PASS TO OUR NORTHWEST SUCH THAT THE FRONT MAY SLOW AND DIE OVER THE REGION NEXT MONDAY. AT THIS POINT...NO SUBSTANTIAL COLD AIR WILL ARRIVE BEHIND THIS COLD FRONT INTO NEXT WEEK. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 1235 PM EDT TUESDAY... OVERALL VFR WILL CONTINUE THIS AFTERNOON...ALTHOUGH WILL SEE SCATTERED TO ISOLATED CONVECTION BUBBLE UP ALONG THE BLUE RIDGE AND POINTS NORTH ESPCLY BETWEEN KLWB AND KLYH. COVERAGE IS EXPECTED TO BE SPOTTY WITH LOW CONFIDENCE IN SEEING A SHOWER OR STORM DIRECTLY AFFECT A SPECIFIC TAF SITE SO WILL MAINTAIN A VICINITY MENTION FROM KROA/KBCB AND POINTS WEST FOR A FEW HOURS THIS AFTERNOON. HOWEVER VARIED CONDITIONS WILL EXIST IN AND NEAR STORMS WITH A QUICK DROPOFF TO MVFR/IFR WITH LOCALLY STRONG WIND GUSTS POSSIBLE NEAR ANY TSRA. TONIGHT...ANY CONVECTION DIES OFF AND SKIES CLEAR OUT SOME. INCREASING LOW LEVEL MOISTURE SHOULD PROMPT AT LEAST SOME PATCHY FOG ACROSS THE VALLEYS AND MORE WIDESPREAD COVERAGE WHERE EARLIER SHOWERS MAY HAVE OCCURRED. FOR NOW WILL INCLUDE SOME HIGH END MVFR FOG MENTION AT THE TYPICAL FOGGY SPOTS LIKE KLWB/KLYH BUT COULD TREND IFR IN ANY LOCATION THAT SEES A HEAVIER SHOWER FROM THIS AFTERNOON. MOIST AND UNSTABLE AIR STAYS AROUND THROUGH THE WEEK. HOWEVER HEIGHTS WILL BE BUILDING THROUGH LATE WEEK AS THE UPPER RIDGE STRENGTHENS OVER THE MISSISSIPPI VALLEY. ONLY ISOLATED TO SCATTERED OROGRAPHIC DRIVEN CONVECTION FOR MID AND LATE WEEK. PATCHY LATE NIGHT FOG ALSO LIKELY DURING THE OVERNIGHTS ESPCLY VALLEYS AND WHERE AFTERNOON/EVENING RAINFALL OCCURS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...JH/WP SHORT TERM...NF LONG TERM...KM AVIATION...JH/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1011 AM EDT TUE MAY 28 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH THE WEEK WITH ABOVE NORMAL TEMPERATURES AND ISOLATED CHANCES FOR STORMS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1005 AM EDT TUESDAY... MAIN CONCERN WITH POTENTIAL CONVECTIVE COVERAGE THIS AFTERNOON AS A FAINT IMPULSE MOVES ACROSS FROM WEST OF THE MOUNTAINS AND COMBINES WITH HEATING AND RETURNING DEEPER MOISTURE. MODIFIED MORNING SOUNDINGS DO SHOW SOME MODEST CAPE OF 1000-1500 J/KG FROM THE BLUE RIDGE EAST ALTHOUGH APPEARS FOCUS LACKING HEADING EAST. LATEST HRRR OUTPUT CONTINUES TO SHOW SHRA/TSRA UNZIPPING ALONG THE BLUE RIDGE FROM SW TO NE AS AIDED BY DIFF HEATING EARLY AND WEAK CONVERGENCE PER LOW LEVEL WINDS TURNING MORE SOUTHERLY LATER ON. SIMILAR DEPICTION FROM THE RNK-WRF AND TO SOME DEGREE THE LATEST NAM SUPPORT AT LEAST A SCATTERING OF POPS BLUE RIDGE AND POINTS NORTH CLOSER TO THE UPPER SUPPORT AND PERHAPS LATER OUTFLOW. WILL KEEP IN SLIGHT POPS ESLW FOR A POP UP STORM OR TWO WITH LEAST COVERAGE SE. ANY SEVERE THREAT WOULD LOOK TO COME FROM PULSE NATURE STORMS IF CONVECTION CAN GET DEEP ENOUGH GIVEN STEEP LAPSES AND LOW WET BULB ZERO VALUES THIS AFTERNOON. MORNING THICKNESS OFF RAOBS SHOW HIGHS WELL INTO THE 70S AND LOWER 80S WEST GIVEN INCREASING INSOLATION AFTER EARLY MID DECK...AND MOSTLY MID 80S EAST AS A DECENT 85H JET MIXES DOWN SOME OF THE INVADING WARMER AIR ALOFT. TONIGHT...ANY CONVECTION WILL GO AWAY AFTER SUNSET WITH SKIES BECOMING MOSTLY CLEAR. WITH HUMIDITY INCREASING THERE MAY BE A BETTER CHANCE FOR FOG IN THE MOUNTAINS AND RIVER VALLEYS...AND WHERE ANY RAIN OCCURS THIS AFTERNOON. LOWS WILL RANGE FROM THE MID 50S OVER THE MOUNTAIN VALLEYS TO LOWER 60S EAST. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM EDT TUESDAY... WILL START WEDNESDAY OUT WITH UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES...WHILE A NEGATIVELY TILTED UPPER LEVEL TROUGH DIGS FROM THE PACIFIC NORTHWEST ALL THE WAY INTO WEST TEXAS. WE MAY SEE A FEW SHOWERS AND THUNDERSTORMS DEVELOP ALONG OUR MOUNTAINS DURING THE AFTERNOON AND EVENING...BUT RIDGING ALOFT WILL KEEP THIS ACTIVITY ISOLATED AND WEAK. RIDGING WILL ALSO ALLOW FOR WARMER AFTERNOON TEMPERATURES...WITH HIGHS RANGING FROM THE UPPER 70S TO THE MID 80S ACROSS THE MOUNTAINS...AND NEAR 90 ACROSS THE PIEDMONTS. THE WEATHER PATTERN WILL REMAIN LITTLE CHANGED THROUGH THE END OF THE WORKWEEK...WITH UPPER LEVEL RIDGING KEEPING PRECIPITATION LIMITED TO ISOLATED SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EVENING FOR THURSDAY AND FRIDAY...MAINLY ACROSS THE MOUNTAINS. HIGHS WILL RANGE FROM THE LOW/MID 80S WEST TO THE LOW 90S EAST...WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOW 60S AREAWIDE. && .LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 333 PM EDT MONDAY... MOST OF THE WEEKEND WILL CONTINUE TO BE HOT AND DRY...WITH DEWPOINTS INCREASING SOMEWHAT DURING THE SECOND HALF OF THE WEEKEND AS A FRONT SLOWS THROUGH THE OHIO VALLEY TRYING TO DISPLACE THE UPPER RIDGE. POSSIBLY BE ABLE TO SQUEAK IN ANOTHER MOSTLY DRY DAY ON SUNDAY WITH MOST SHOWERS AND STORMS ARRIVING SUNDAY NIGHT AND MONDAY...FOLLOWING THE 12Z ECMWF TIMING. MOST OF THE SUPPORT FOR THIS BOUNDARY WILL PASS TO OUR NORTHWEST SUCH THAT THE FRONT MAY SLOW AND DIE OVER THE REGION NEXT MONDAY. AT THIS POINT...NO SUBSTANTIAL COLD AIR WILL ARRIVE BEHIND THIS COLD FRONT INTO NEXT WEEK. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... AS OF 725 AM EDT TUESDAY... GOING TO BE SEEING VFR WEATHER FOR MOST OF THE PERIOD...ALTHOUGH WILL SEE SCATTERED TO ISOLATED CONVECTION AFTER MIDDAY TODAY ACROSS THE BLUE RIDGE AND NORTH AND WEST TO WV. COVERAGE WILL BE SUCH THAT NO EFFECT WILL BE MADE TO THE AVIAITON FORECAST EXCEPT KEEPING VCTS AT LWB WHERE A BETTER THAN 30 PERCENT CHANCE EXISTS FOR NOW. TONIGHT...ANY CONVECTION DIES OFF AND SKIES CLEAR OUT SOME. ATTM...WILL LEAVE FOG OUT BUT WITH INCREASED MOISTURE IN THE LOW LVLS AND POTENTIAL FOR SHOWERS...FOG COULD FORM AT THE FAVORED AIRPORTS LIKE LWB/BCB. MOIST AND UNSTABLE AIR STAYS AROUND THROUGH THE WEEK. HOWEVER HEIGHTS WILL BE BUILDING THROUGH LATE WEEK AS THE UPPER RIDGE STRENGTHENS OVER THE MISSISSIPPI VALLEY. ONLY ISOLATED TO SCATTERED OROGRAPHIC DRIVEN CONVECTION FOR MID AND LATE WEEK. PATCHY LATE NIGHT FOG ALSO LIKELY DURING THE OVERNIGHTS ESPCLY VALLEYS AND WHERE AFTERNOON/EVENING RAINFALL OCCURS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...JH/WP SHORT TERM...NF LONG TERM...KM AVIATION...WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
958 AM EDT TUE MAY 28 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH THE WEEK WITH ABOVE NORMAL TEMPERATURES AND ISOLATED CHANCES FOR STORMS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 935 AM EDT TUESDAY... MAIN CONCERN WITH POTENTIAL CONVECTIVE COVERAGE THIS AFTERNOON AS A FAINT IMPULSE MOVES ACROSS FROM WEST OF THE MOUNTAINS AND COMBINES WITH HEATING AND RETURNING DEEPER MOISTURE. MODIFIED MORNING SOUNDINGS DO SHOW SOME MODEST CAPE OF 1000-1500 J/KG FROM THE BLUE RIDGE EAST ALTHOUGH APPEARS FOCUS LACKING HEADING EAST. LATEST HRRR OUTPUT CONTINUES TO SHOW SHRA/TSRA UNZIPPING ALONG THE BLUE RIDGE FROM SW TO NE AS AIDED BY DIFF HEATING EARLY AND WEAK CONVERGENCE PER LOW LEVEL WINDS TURNING MORE SOUTHERLY LATER ON. SIMILAR DEPICTION FROM THE RNK-WRF AND TO SOME DEGREE THE LATEST NAM SUPPORT AT LEAST A SCATTERING OF POPS BLUE RIDGE AND POINTS NORTH CLOSER TO THE UPPER SUPPORT AND PERHAPS LATER OUTFLOW. WILL KEEP IN SLIGHT POPS ESLW FOR A POP UP STORM OR TWO WITH LEAST COVERAGE SE. MORNING THICKNESS OFF RAOBS SHOW HIGHS WELL INTO THE 70S AND LOWER 80S WEST GIVEN INCREASING INSOLATION AFTER EARLY MID DECK...AND MOSTLY MID 80S EAST AS A DECENT 85H JET MIXES DOWN SOME OF THE INVADING WARMER AIR ALOFT. TONIGHT...ANY CONVECTION WILL GO AWAY AFTER SUNSET WITH SKIES BECOMING MOSTLY CLEAR. WITH HUMIDITY INCREASING THERE MAY BE A BETTER CHANCE FOR FOG IN THE MOUNTAINS AND RIVER VALLEYS...AND WHERE ANY RAIN OCCURS THIS AFTERNOON. LOWS WILL RANGE FROM THE MID 50S OVER THE MOUNTAIN VALLEYS TO LOWER 60S EAST. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM EDT TUESDAY... WILL START WEDNESDAY OUT WITH UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES...WHILE A NEGATIVELY TILTED UPPER LEVEL TROUGH DIGS FROM THE PACIFIC NORTHWEST ALL THE WAY INTO WEST TEXAS. WE MAY SEE A FEW SHOWERS AND THUNDERSTORMS DEVELOP ALONG OUR MOUNTAINS DURING THE AFTERNOON AND EVENING...BUT RIDGING ALOFT WILL KEEP THIS ACTIVITY ISOLATED AND WEAK. RIDGING WILL ALSO ALLOW FOR WARMER AFTERNOON TEMPERATURES...WITH HIGHS RANGING FROM THE UPPER 70S TO THE MID 80S ACROSS THE MOUNTAINS...AND NEAR 90 ACROSS THE PIEDMONTS. THE WEATHER PATTERN WILL REMAIN LITTLE CHANGED THROUGH THE END OF THE WORKWEEK...WITH UPPER LEVEL RIDGING KEEPING PRECIPITATION LIMITED TO ISOLATED SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EVENING FOR THURSDAY AND FRIDAY...MAINLY ACROSS THE MOUNTAINS. HIGHS WILL RANGE FROM THE LOW/MID 80S WEST TO THE LOW 90S EAST...WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOW 60S AREAWIDE. && .LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 333 PM EDT MONDAY... MOST OF THE WEEKEND WILL CONTINUE TO BE HOT AND DRY...WITH DEWPOINTS INCREASING SOMEWHAT DURING THE SECOND HALF OF THE WEEKEND AS A FRONT SLOWS THROUGH THE OHIO VALLEY TRYING TO DISPLACE THE UPPER RIDGE. POSSIBLY BE ABLE TO SQUEAK IN ANOTHER MOSTLY DRY DAY ON SUNDAY WITH MOST SHOWERS AND STORMS ARRIVING SUNDAY NIGHT AND MONDAY...FOLLOWING THE 12Z ECMWF TIMING. MOST OF THE SUPPORT FOR THIS BOUNDARY WILL PASS TO OUR NORTHWEST SUCH THAT THE FRONT MAY SLOW AND DIE OVER THE REGION NEXT MONDAY. AT THIS POINT...NO SUBSTANTIAL COLD AIR WILL ARRIVE BEHIND THIS COLD FRONT INTO NEXT WEEK. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... AS OF 725 AM EDT TUESDAY... GOING TO BE SEEING VFR WEATHER FOR MOST OF THE PERIOD...ALTHOUGH WILL SEE SCATTERED TO ISOLATED CONVECTION AFTER MIDDAY TODAY ACROSS THE BLUE RIDGE AND NORTH AND WEST TO WV. COVERAGE WILL BE SUCH THAT NO EFFECT WILL BE MADE TO THE AVIAITON FORECAST EXCEPT KEEPING VCTS AT LWB WHERE A BETTER THAN 30 PERCENT CHANCE EXISTS FOR NOW. TONIGHT...ANY CONVECTION DIES OFF AND SKIES CLEAR OUT SOME. ATTM...WILL LEAVE FOG OUT BUT WITH INCREASED MOISTURE IN THE LOW LVLS AND POTENTIAL FOR SHOWERS...FOG COULD FORM AT THE FAVORED AIRPORTS LIKE LWB/BCB. MOIST AND UNSTABLE AIR STAYS AROUND THROUGH THE WEEK. HOWEVER HEIGHTS WILL BE BUILDING THROUGH LATE WEEK AS THE UPPER RIDGE STRENGTHENS OVER THE MISSISSIPPI VALLEY. ONLY ISOLATED TO SCATTERED OROGRAPHIC DRIVEN CONVECTION FOR MID AND LATE WEEK. PATCHY LATE NIGHT FOG ALSO LIKELY DURING THE OVERNIGHTS ESPCLY VALLEYS AND WHERE AFTERNOON/EVENING RAINFALL OCCURS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...JH/WP SHORT TERM...NF LONG TERM...KM AVIATION...WP
AREA FORECAST DISCUSSION
NWS SPOKANE WA
446 PM PDT Wed May 29 2013 .SYNOPSIS... Low pressure aloft will keep a chance for showers Thursday with the highest threat for rain focusing over the northern and eastern mountains. Most of the region will experience dry conditions Friday coupled with warming temperatures. The warming trend will continue into the weekend with a few weak disturbances expected to clip far northeastern Washington and the Idaho Panhandle keeping a small chance for showers in the forecast. && .DISCUSSION... Tonight...Slow moving upper level shortwave trough will remain the dominant feature for tonight`s weather. As of 2pm...the base of the trough was located near the Tri-Cities and was moving slowly to the east-northeast. A NW-SE band of precipitation ahead of the trough will deliver stratiform precipitation to locations over NE Washington and much of the Idaho Panhandle through early evening. Strangely enough this band moved over the Spokane area and generally fell apart...but it remains intact to the northwest and southeast. This band will likely weaken during the evening...and most of the precipitation then will result from the unstable conditions behind the band. The HRRR model continues to forecast SBCAPE values between 300-700 j/kg over the southern Columbia Basin near the negatively tilted trough axis through this afternoon...before shifting it toward the WA/ID border by early evening. This roughly matches whats transpiring on the latest radar and satellite imagery with a line of showers and embedded thunderstorms developing along a line from Mattawa to Walla Walla. The threat of thunderstorms will likely persist through mid- evening before tapering off overnight. Meanwhile elevated instability ahead of the trough could still result in a few showers through the night especially over extreme NE Washington and the Idaho Panhandle. fx Thursday through Saturday night: A northwest to southeast oriented upper-level trof will remain anchored over the Inland NW Thursday then begin a slow migration northward Friday and Saturday. This will keep the threat for showers across the region on Thursday with a drying trend for Friday. Another weak wave will track across northern WA/ID late Saturday/Saturday night bringing a small chance for showers but for the most part...most locations will continue to experience generally dry conditions. For Thursday, 500mb temperatures around -20C within the inner trof will keep a pool of instability over the region. This is expected to equate to widely scattered afternoon showers. The northern and eastern mountains...expanding into the upper Columbia Basin will carry the highest threat for precipitation. Across the southern Columbia Basin and East Slopes...tightening pressure gradients will bring a slight increase in winds which should help dry out the boundary layer...resulting in decreasing surface based instability and lowering chances for showers through the afternoon. The trof will begin to migrate northward on Friday with models indicating almost 6C of warming aloft (500mb). With the exception of the far northern mountains...a dry day is in store for most and only the ECMWF lingers enough instability over the northern mountains to keep a slight chance of showers in the forecast. On Saturday, a ridge of high pressure begins to amplify over the Gulf of AK allowing a shortwave to drop into the region from the northwest. This does not look like a very wet system but will bring a slight increase in the threat for showers mainly north of a line from Kellogg to Omak through the Saturday evening and night time-frame. Temperatures through the period will start off below normal and slowly warm near normal by the weekend. This equates to highs in 60`s to low 70`s Thursday...warming into the 70`s to low 80`s on Saturday. A few cold pockets within the northern mountains will continue to drop into the 30`s at night but are expected to remain just above freezing. /sb Sunday through Wednesday: Models are in pretty good agreement of an upper level low pressure system pushing through the Inland Northwest Sunday. Latest ECMWF is a bit more robust and further south with the low...bringing it along the WA/Canadian border. GFS seems to be trending more towards an unsettled day as well. There are still some discrepancies with this feature though. Have increased chance of precipitation from the Spokane area north towards the Canadian border and east to the MT state line for the afternoon and early evening hours. There is even some instability associated with the system moving through. For now have kept mention of thunder out of the forecast, but will need to be evaluated again as models come more in line with each other. Monday the trough moves out of the area but showers are still possible along the Idaho Panhandle. Tuesday and Wednesday a ridge of high pressure will move into the Pacific Northwest. Have decreased chance of precipitation and sky cover. Temperatures Sunday will be below average and then trend to average by Monday and above average for Tue and Wed. /Nisbet && .AVIATION... 00Z TAFS: Scattered showers and embedded thunderstorms will continue across eastern WA/N ID within an unstable upper trough through 03-06z, before shifting toward the north/northeast mountains and dissipating. Primarily VFR conditions are expected but local MVFR cigs/vis are possible in heavier showers and winds could be gusty and erratic. Overnight into Thursday morning there is a threat of IFR/MVFR stratus developing across the KGEG-KCOE and KPUW with a moist southwest flow. Confidence in its occurrence is low. By mid to late morning Thursday the stratus threat wanes, with another threat of showers developing across the northeast, possibly near KGEG-KCOE and KPUW. Some gusty wind are also expected near the Cascades/Basin, including near KEAT in the afternoon. /J. Cote` && .PRELIMINARY POINT TEMPS/POPS... Spokane 43 62 44 67 45 71 / 70 20 20 0 0 10 Coeur d`Alene 44 60 42 67 42 71 / 70 30 20 10 0 10 Pullman 41 58 40 66 41 71 / 70 20 10 0 0 0 Lewiston 46 68 46 73 47 79 / 60 20 10 0 0 0 Colville 47 65 43 74 43 75 / 80 50 20 10 0 20 Sandpoint 45 58 42 67 40 70 / 70 60 30 10 10 10 Kellogg 42 55 41 62 43 68 / 70 50 30 10 0 10 Moses Lake 46 72 46 74 47 78 / 50 10 0 0 0 10 Wenatchee 46 71 49 74 50 76 / 50 10 0 0 0 10 Omak 45 68 43 74 45 76 / 60 20 10 10 0 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
444 AM PDT Tue May 28 2013 .SYNOPSIS... Today and tomorrow will be showery and cool as a pair of upper level disturbances move through the Pacific Northwest. The low pressure pattern will begin to break down on Thursday, and we will likely begin to see some clearing over central Washington. By Friday and into the weekend, weak high pressure is expected to bring a good deal of sunshine and temperatures at or above average. && .DISCUSSION... Today through Wednesday night...Longwave trof remains in place overhead of Eastern Washington and Northern Idaho through this time interval. The cool pool contained in the trof keeps a somewhat unstable air mass in place. The model vorticity fields remain cluttered and hint at numerous small scale disturbances in vicinity through this period so pops never really zero out but have maximums associated with most significant shortwave features of note. This includes a very small synoptic scale negatively tilted trof passing through Today. The HRRR does a very good job of resolving a thin line of convective showers and possibly a thunderstorm or two associated with this trof passage and additionally hints at some orographically forced showers produced this afternoon and evening. Since instability is greatest near the British Columbia border have limited the inclusion of slight chance of thunderstorm mention for today to the northern mountains and don`t extend them too far south. Tuesday night has decrease in convective showers but no end as models continue to hint at presence of mesoscale shortwaves capable of generating them... with most model runs focusing activity generally near northern mountain locations highest pops are there as well. Wednesday yet another negatively tilted very small synoptic scale disturbance moves through tracking west to east near the Oregon/Washington border that is depicted to take a turn and track northeast Wednesday evening thus pops depict this same scenario. This disturbance passing Tuesday night into Wednesday has the best orientation to its moisture tap via an almost south to north trajectory, therefore it should not have any problems getting through and a cascades rain shadow will not be produced. Forecast temperatures remain on the cool side of what would be considered normal for this time of year given this general trof pattern. /Pelatti Thursday: There is still a good deal of uncertainty with the forecast for Thursday. An elongated upper trough extending from south of the Aleutians into the Central Plains will bisect the state of Washington. This "mucky" upper trough will likely contain some mesoscale feature within it, but it is very tough to forecast where these little vorticity centers will be at this time. The 00z GFS is the wettest of the models for Thursday for the Idaho Panhandle and northeast Washington when compared to the NAM, ECMWF, SREF and Canadian. So, it is hard to get more excited than carrying a 20-50 percent chance of showers for the eastern third of Washington into the Idaho Panhandle, with the highest chances near the ID/MT border. Lingering showers and clouds will have a big influence on high temperatures, so there is a high bust potential given the uncertainty in the precipitation forecast. Friday through Sunday: There is good model agreement that the ridiculously elongated upper trough will be broken into pieces by Friday. A shortwave upper ridge is forecast to develop over the Pacific Northwest Friday and Saturday bringing an end to the threat of organized shower activity. Temperatures should moderate to average during this time frame as well. The shortwave ridge is expected to be replaced by an upper low descending into southern British Columbia on Sunday. This low will not be particularly cold aloft and the high amplitude ridge upstream will cut off any deep moisture tap. The ECMWF and Canadian models are colder and more unstable aloft near the Canadian border than the GFS. Slight chances for showers have been mentioned mainly for the mountain zones near the B.C. border. /GKoch Sunday night through Tuesday: A Northwest flow pattern will prevail through this period as high pressure ridging from the South Pacific will press North into the region. This ridging will keep will keep a passing system in southern BC. Any precip associated with this Low will be mainly in the Northern Mountains of the Idaho Panhandle but is hard to be certain as the model agreement is low. Temperatures are expected to be near seasonal norms during this period. /JDC && .AVIATION... 12Z TAFS: Occluded frontal zone has exited away to the northeast and into Canada and Northwest Montana while unstable air with disturbances rotating through it bring more showers approaching fromt the south and west through the day. MVFR Ceilings may occur at times but VFR should prevail. After 02Z Wednesday majority of the convection should be decreased but not totally gone..and later near 10Z some low cloud formation most locations but also some shallow ground fog as well. /Pelatti && .PRELIMINARY POINT TEMPS/POPS... Spokane 64 45 62 46 62 46 / 50 30 40 30 30 20 Coeur d`Alene 63 43 63 45 60 44 / 50 40 40 30 40 30 Pullman 62 43 60 43 60 43 / 30 30 40 40 20 10 Lewiston 68 48 67 48 67 48 / 30 20 60 50 20 10 Colville 68 44 68 46 65 45 / 60 60 50 40 50 20 Sandpoint 62 42 63 45 57 43 / 60 60 50 40 50 30 Kellogg 59 44 58 45 55 43 / 60 60 60 50 60 40 Moses Lake 72 47 69 49 72 47 / 20 10 40 30 10 10 Wenatchee 68 49 66 50 69 49 / 20 10 50 30 10 10 Omak 70 45 69 46 69 45 / 50 30 30 20 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
244 AM PDT Tue May 28 2013 .SYNOPSIS... Today and tomorrow will be showery and cool as a pair of upper level disturbances move through the Pacific Northwest. The low pressure pattern will begin to break down on Thursday, and we will likely begin to see some clearing over central Washington. By Friday and into the weekend, weak high pressure is expected to bring a good deal of sunshine and temperatures at or above average. && .DISCUSSION... Today through Wednesday night...Longwave trof remains in place overhead of Eastern Washington and Northern Idaho through this time interval. The cool pool contained in the trof keeps a somewhat unstable air mass in place. The model vorticity fields remain cluttered and hint at numerous small scale disturbances in vicinity through this period so pops never really zero out but have maximums associated with most significant shortwave features of note. This includes a very small synoptic scale negatively tilted trof passing through Today. The HRRR does a very good job of resolving a thin line of convective showers and possibly a thunderstorm or two associated with this trof passage and additionally hints at some orographically forced showers produced this afternoon and evening. Since instability is greatest near the British Columbia border have limited the inclusion of slight chance of thunderstorm mention for today to the northern mountains and don`t extend them too far south. Tuesday night has decrease in convective showers but no end as models continue to hint at presence of mesoscale shortwaves capable of generating them... with most model runs focusing activity generally near northern mountain locations highest pops are there as well. Wednesday yet another negatively tilted very small synoptic scale disturbance moves through tracking west to east near the Oregon/Washington border that is depicted to take a turn and track northeast Wednesday evening thus pops depict this same scenario. This disturbance passing Tuesday night into Wednesday has the best orientation to its moisture tap via an almost south to north trajectory, therefore it should not have any problems getting through and a cascades rain shadow will not be produced. Forecast temperatures remain on the cool side of what would be considered normal for this time of year given this general trof pattern. /Pelatti Thursday: There is still a good deal of uncertainty with the forecast for Thursday. An elongated upper trough extending from south of the Aleutians into the Central Plains will bisect the state of Washington. This "mucky" upper trough will likely contain some mesoscale feature within it, but it is very tough to forecast where these little vorticity centers will be at this time. The 00z GFS is the wettest of the models for Thursday for the Idaho Panhandle and northeast Washington when compared to the NAM, ECMWF, SREF and Canadian. So, it is hard to get more excited than carrying a 20-50 percent chance of showers for the eastern third of Washington into the Idaho Panhandle, with the highest chances near the ID/MT border. Lingering showers and clouds will have a big influence on high temperatures, so there is a high bust potential given the uncertainty in the precipitation forecast. Friday through Sunday: There is good model agreement that the ridiculously elongated upper trough will be broken into pieces by Friday. A shortwave upper ridge is forecast to develop over the Pacific Northwest Friday and Saturday bringing an end to the threat of organized shower activity. Temperatures should moderate to average during this time frame as well. The shortwave ridge is expected to be replaced by an upper low descending into southern British Columbia on Sunday. This low will not be particularly cold aloft and the high amplitude ridge upstream will cut off any deep moisture tap. The ECMWF and Canadian models are colder and more unstable aloft near the Canadian border than the GFS. Slight chances for showers have been mentioned mainly for the mountain zones near the B.C. border. /GKoch Sunday night through Tuesday: A Northwest flow pattern will prevail through this period as high pressure ridging from the South Pacific will press North into the region. This ridging will keep will keep a passing system in southern BC. Any precip associated with this Low will be mainly in the Northern Mountains of the Idaho Panhandle but is hard to be certain as the model agreement is low. Temperatures are expected to be near seasonal norms during this period. /JDC && .AVIATION... 06Z TAFS: The mid level occluded front is currently stretching from KPUW to KSEA over the region. Out ahead of this front is a band of light stratiform rain. Once this band clears the taf sites, we are expecting a layer of low stratus to develop across much of the region, especially north of a line from KMWH to KPUW. This stratus will result in MVFR cigs and vis with localized IFR cigs possible. Another batch of showers will move northeast out of northeast Oregon later tonight into early tomorrow morning. These showers will become more widespread through the afternoon hours on Tuesday with the stratus lifting into a stratocumulus deck with VFR conditions returning by this time. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 64 45 62 46 62 46 / 50 30 40 30 30 20 Coeur d`Alene 63 43 63 45 60 44 / 50 40 40 30 40 30 Pullman 62 43 60 43 60 43 / 30 30 40 40 20 10 Lewiston 68 48 67 48 67 48 / 30 20 60 50 20 10 Colville 68 44 68 46 65 45 / 60 60 50 40 50 20 Sandpoint 62 42 63 45 57 43 / 60 60 50 40 50 30 Kellogg 59 44 58 45 55 43 / 60 60 60 50 60 40 Moses Lake 72 47 69 49 72 47 / 20 10 40 30 10 10 Wenatchee 68 49 66 50 69 49 / 20 10 50 30 10 10 Omak 70 45 69 46 69 45 / 50 30 30 20 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
714 PM CDT WED MAY 29 2013 .UPDATE... ISSUED AT 714 PM CDT WED MAY 29 2013 HAVE EXPANDED THE FLASH FLOOD WATCH EVEN FARTHER EAST TO NOW INCLUDE VERNON...CRAWFORD...RICHLAND AND GRANT COUNTIES IN WISCONSIN. CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN HAS ENTERED THESE COUNTIES. MEANWHILE...THE ENTIRE MCS OVER THE FORECAST AREA EXTENDING DOWN TO MARSHALLTOWN AND CEDAR RAPIDS IOWA SHOULD LIFT NORTH THROUGH THE NIGHT...IN RESPONSE TO STRENGTHENING LOW LEVEL JET / MOISTURE TRANSPORT. THIS MEANS THE EXPANDED FLASH FLOOD WATCH AREA COULD SEE PERIODS OF MODERATE TO HEAVY RAINFALL FOR AT LEAST THE NEXT FEW HOURS. UPDATE ISSUED AT 429 PM CDT WED MAY 29 2013 HAVE EXPANDED THE FLASH FLOOD WATCH EASTWARD TO INCLUDE HOUSTON...ALLAMAKEE AND CLAYTON COUNTIES. PRESENT CONVECTION TRACKING ACROSS WESTERN PORTIONS OF THE FORECAST AREA HAS BEEN MOVING MORE SLOWLY ACROSS NORTHEAST IOWA...PRIMARILY DUE TO LOWER 0-6KM SHEAR THERE. AS THIS CONVECTION MOVES INTO THE EXPANSION AREA...EXPECTING THE RAIN TO PRIME CONDITIONS FOR POSSIBLE FLASH FLOODING...EITHER FROM THE CURRENT CONVECTION OR FROM ADDITIONAL EXPECTED CONVECTION LATER TONIGHT INTO THURSDAY. ALSO STARTED THE FLASH FLOOD WATCH NOW GIVEN CURRENT CONVECTION AND THE NEED FOR WARNINGS SOONER THAN EXPECTED. && .SHORT TERM...(TONIGHT THROUGH THURSDAY) ISSUED AT 308 PM CDT WED MAY 29 2013 MAIN CONCERN IS SEVERE POTENTIAL GOING INTO THIS EVENING AND HEAVY RAINFALL POTENTIAL THROUGH THURSDAY. WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWS A DEEPENING TROUGH OF LOW PRESSURE ACROSS THE CENTRAL ROCKIES INTO THE SOUTHERN PLAINS. THIS IN TURN WAS DRIVING AN INCREASINGLY MOIST/UNSTABLE SOUTHERLY SURFACE FLOW FROM THE PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AT THE SURFACE LOW PRESSURE WAS LOCATED OVER SOUTHEAST CO WITH A WARM FRONT EXTENDING NORTHEAST THROUGH IA INTO SOUTHERN WI. CONVECTION/SOME STRONG TO SEVERE WAS FIRING ALONG/AHEAD OF THIS WARM FRONT ON THE NOSE OF INCREASING 925-85OMB MOISTURE TRANSPORT/INCREASING CAPE POOL. DEW POINTS ACROSS OUR AREA THIS AFTERNOON WERE IN THE MID/UPPER 60S WITH AROUND 70 ACROSS EASTERN IA. LOOK FOR ONGOING SHOWER/THUNDERSTORM ACTIVITY THIS EVENING AS THE WARM FRONT/NOSE OF RATHER INTENSE MOISTURE TRANSPORT CONTINUES TO PUSH NORTH ACROSS THE AREA. RAP SHOWING 0-1KM MLCAPE IN THE 3000-3500J/KG WITH INCREASING 0-3KM BULK SHEAR IN THE 25-35KT RANGE BETWEEN 4 PM AND 8 PM ACROSS PORTIONS OF NORTHEAST IA/SOUTHWEST WI. CAPE/BULK SHEAR AND ENHANCED 0-1KM EHI VALUES WOULD FAVOR TORNADOGENESIS ALONG THE WARM FRONT AS IT PUSHES THROUGH NORTHEAST IA/SOUTHWEST WI. WILL HAVE TO KEEP AN EYE ON LARGE HAIL/DAMAGING WIND/TORNADIC POTENTIAL GOING INTO EVENING. CAPE STARTS DWINDLING AFTER SUNSET...HOWEVER...MODELS CONTINUE TO SHOW FETCH OF STRONG 925-850MB MOISTURE TRANSPORT ADVECTING INTO OUR AREA OVERNIGHT INTO THURSDAY. THIS WILL BE AHEAD OF A COLD FRONT PUSHING EASTWARD INTO THE CENTRAL PLAINS. PRECIPITABLE WATER VALUES INCREASE INTO THE 1.5 TO 1.7IN RANGE. WITH THIS IN MIND THERE WILL BE THE POTENTIAL WILL BE THERE FOR SOME HEAVY RAINFALL. HAVE ISSUED A FLASH FLOOD WATCH FOR PORTIONS OF THE AREA THIS EVENING THROUGH THURSDAY TO COVER THIS. SEE THE HYDROLOGY SECTION BELOW FOR FURTHER DETAILS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 308 PM CDT WED MAY 29 2013 MAIN AXIS OF MOISTURE TRANSPORT/ENHANCED PRECIPITABLE WATER SHIFTS EAST OF THE AREA THURSDAY NIGHT WITH A COLD FRONT LAGGING ACROSS CENTRAL MN INTO EASTERN NEBRASKA/CENTRAL KS. SO...EXPECTING HEAVIER RAINFALL TO TAPER OFF IN THE EVENING/OVERNIGHT FROM WEST TO EAST. THE COLD FRONT WILL CONTINUE TO PUSH SLOWLY EAST INTO THE AREA FRIDAY WITH INCREASING MOISTURE TRANSPORT INTO FAR SOUTHERN WI DURING THE AFTERNOON. HAVE TAILORED SHRA/TS CHANCES WITH LIKELY ACROSS THE SOUTH...TAPERING TO 40-50 POPS ACROSS THE NORTHWEST. FOR FRIDAY NIGHT THROUGH SUNDAY...LOOK FOR A MID-LEVEL CLOSED LOW TO MAKE ITS WAY ACROSS THE AREA FOR SCATTERED SHOWERS AND COOLING TEMPERATURES. SUNDAY NIGHT THROUGH MONDAY LOOKS DRY AND COOL AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE PLAINS. SHOWER/THUNDERSTORM CHANCES RETURN TO THE AREA MONDAY NIGHT THROUGH WEDNESDAY AS ANOTHER CLOSED MID-LEVEL LOW SYSTEM DROPS ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGION. THIS SYSTEM WILL ALSO RESULT IN BELOW NORMAL TEMPERATURES THROUGH THIS PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 714 PM CDT WED MAY 29 2013 THUNDERSTORM COMPLEX OVER THE TAF SITES WILL SLOWLY LIFT NORTHEAST THROUGH THE EVENING. THE POTENTIAL FOR STRONG WIND GUSTS HAS ENDED...BUT MVFR RESTRICTIONS TO VISIBILITY WILL LIKELY PERSIST GIVEN POCKETS OF MODERATE TO HEAVY RAINFALL. THUNDERSTORMS THEMSELVES ARE MORE SCATTERED ABOUT...BUT ENOUGH COVERAGE TO WARRANT EITHER VCTS/TSRA THROUGH 03Z. ANTICIPATING MUCH OF THE RAIN TO END BY 06Z. AFTER THIS...THE FORECAST BECOMES MORE MUDDLED IN TERMS OF WHEN SHOWERS AND THUNDERSTORMS WILL AFFECT THE TAF SITES AGAIN. SOME MODELS SUGGEST AT LEAST A BREAK IN THE PRECIPITATION UNTIL 14Z OR SO...OTHERS NOT AS LONG. CERTAINLY HEADING INTO THE DAY THURSDAY THERE LOOKS TO BE PLENTY OF FORCING FOR SHOWERS WITH EMBEDDED THUNDERSTORMS. FOR NOW HAVE FOLLOWED THE PREVIOUS FORECAST WITH VCSH BEGINNING AROUND 12Z AT BOTH TAF SITES. MORE FINE TUNING WILL COME IN FUTURE TAF FORECASTS. IT DOES APPEAR WINDS ARE GOING TO INCREASE ON THURSDAY AHEAD OF A COLD FRONT MARCHING INTO WESTERN PORTIONS OF MINNESOTA AND IOWA. SOUTH WINDS THAT WILL HOLD STEADY BETWEEN 10-15KT TONIGHT LOOK TO INCREASE TO 15-20 KT LATE TOMORROW MORNING WITH GUSTS OF 20-30 KT IN THE AFTERNOON. IF MORE SUN CAN OCCUR TOMORROW...POTENTIAL FOR EVEN STRONGER GUSTS EXISTS...ESPECIALLY AT KRST. && .HYDROLOGY...TONIGHT THROUGH FRIDAY ISSUED AT 714 PM CDT WED MAY 29 2013 PERIODS OF SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF THE REGION THROUGH FRIDAY. THE HEAVIEST RAIN IS EXPECTED TO FALL FROM THURSDAY INTO FRIDAY. TOTAL RAINFALL FROM TODAY THROUGH FRIDAY COULD RANGE FROM 1 TO 3 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THIS COULD LEAD TO FLASH FLOODING AS WELL AS RISES AND POSSIBLE FLOODING ON AREA RIVERS. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR NORTHEAST IA AND PORTIONS OF SOUTHEAST MN AND SOUTHWEST WISCONSIN THROUGH THU. THIS MAY NEED TO BE EXPANDED NORTHWARD AS DETAILS OF TIMING/LOCATION OF THE CONTINUED HEAVY RAIN THREAT BECOME CLEARER. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR WIZ053>055-061. MN...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR MNZ094>096. IA...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR IAZ008>011-018- 019-029-030. && $$ UPDATE...AJ SHORT TERM...DAS LONG TERM....DAS AVIATION...AJ HYDROLOGY....DAS/AJ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
130 PM CDT TUE MAY 28 2013 .UPDATE... SO THE WARM FRONT CREPT INTO SOUTHERN WISCONSIN AND HAS ALREADY REACHED MADISON AND MILWAUKEE EARLY THIS AFTERNOON. THIS IS A LITTLE QUICKER THAN WHAT I WAS THINKING EARLIER THIS MORNING. DEWPOINTS ARE RISING INTO THE MID 60S WITH TEMPS AROUND 70. AN AREA OF SHOWERS DEVELOPED NEAR THE QUAD CITIES AND IS MOVING NORTHEAST INTO JANESVILLE AND KENOSHA AREAS NOW. THESE ARE ASSOCIATED WITH SURFACE THETA-E ADVECTION. SURFACE BASED CAPE IS ON THE RISE...UP TO AROUND 500 J/KG WITH MINIMAL CIN IN SOUTHEAST WI. LOW LEVEL LAPSE RATES ARE FAIRLY WEAK. THUS...ISOLATED THUNDER IS EXPECTED WITH THESE SHOWERS. HRRR MODEL CONTINUES TO KEEP STRONGER CONVECTION SOUTH OF THE WI BORDER TONIGHT...ALTHOUGH THERE WILL STILL BE A CHANCE FOR SHOWERS AND ISOLATED THUNDER TONIGHT GIVEN THAT THE WARM FRONT WILL LIKELY HANG UP OVER THE MKX FORECAST AREA. && .AVIATION/18Z TAFS/... THE WARM FRONT CREPT NORTHWARD QUICKER THAN EXPECTED AND HAS ALREADY CLEARED KMSN AND KMKE...IDENTIFIED BY SOUTHWEST WINDS AND SCOURING OF THE LIFR CIGS. THERE IS AN AREA OF SHOWERS WITH ISOLATED THUNDER ACROSS FAR SOUTHERN WISCONSIN NOW THAT WILL BRIEFLY IMPACT AT LEAST KMKE THROUGH THE NEXT HOUR. THE WARM FRONT IS EXPECTED TO HANG UP NEAR SHEBOYGAN AND THE DELLS THROUGH TONIGHT AND CONTINUE THE TREK NORTHWARD ON WEDNESDAY. UNCERTAIN ABOUT CEILINGS TONIGHT SINCE THE WARM FRONT WILL BE VERY CLOSE TO THE KMSN/KUES/KMKE TAF SITES. AREAS OF DENSE FOG AND LOW CEILINGS WILL BE POSSIBLE MAINLY NORTH OF KMSN AND KMKE TONIGHT ALONG AND NORTH OF THE WARM FRONT. THE CHANCE FOR LIGHT RAIN SHOWERS/DRIZZLE WILL CONTINUE OVER ALL OF SOUTHERN WI THROUGH TONIGHT. CHANCE FOR THUNDER ALONG AND SOUTH OF THE WARM FRONT. EXPECT IMPROVEMENT TO MVFR AND EVENTUALLY VFR AS REGION GETS INTO WARM SECTOR AS WARM FRONT LIFTS INTO CENTRAL WISCONSIN. THIS MAY BE DELAYED UNTIL EARLY WEDNESDAY MORNING. && .PREV DISCUSSION... /ISSUED 1000 AM CDT TUE MAY 28 2013/ UPDATE... LATEST HRRR AND 12Z NAM ARE NOW KEEPING THE SURFACE WARM FRONT FURTHER SOUTH THAN PREVIOUS RUNS. GIVEN THE MORNING ROUND OF SHOWERS AND STORMS...EFFECTIVE WARM FRONT WILL BE DELAYED IN MOVING NORTHWARD TODAY. MODELS STILL SHOW IT PUSHING INTO FAR SOUTHERN WISCONSIN BY LATE AFTERNOON...BUT THEN HAVING IT STALL THIS EVENING AND BISECT THE MKX FORECAST AREA. CHANCE OF LIGHT SHOWERS/SPRINKLES/DRIZZLE WILL CONTINUE THROUGH TODAY AND ALSO TONIGHT WITH THE VICINITY OF THE WARM FRONT...BUT ANY STORMS DEVELOPING IN THE REGION ARE EXPECTED TO STAY SOUTH OF THE WI/IL BORDER THROUGH LATE TONIGHT. THE LOW LEVEL JET IS JUST BARELY OVER SOUTHERN WI TODAY...BUT GENERALLY POINTING TOWARD LOWER MICHIGAN. LEFT THE SLIGHT CHANCE FOR THUNDER IN THE FORECAST FOR NOW GIVEN SOME ELEVATED CAPE. HEADLINE POTENTIAL FOR TONIGHT WILL BE DENSE FOG. WITH LIGHT EASTERLY FLOW AT THE SURFACE ON THE NORTH SIDE OF THE WARM FRONT...AREAS OF FOG ARE EXPECTED AND COULD BECOME DENSE. BEST CHANCE FOR DENSE FOG WOULD BE THE NORTH HALF OF THE MKX FORECAST AREA. AVIATION/18Z TAFS/... THE WARM FRONT AND HIGHER CEILINGS ARE JUST SOUTH OF THE WI/IL BORDER...BUT NOT EXPECTING THAT FRONT TO MOVE NORTHWARD QUICKLY TODAY OR TONIGHT. KENW AND KJVL COULD SCOUR OUT THE LIFR CIGS BY MIDDAY...BUT KMSN/KUES/KMKE WILL LIKELY REMAIN LIFR/IFR THROUGH MOST OF TONIGHT. PATCHY FOG EXPECTED ACROSS MUCH OF THE SOUTHERN WI TODAY...THEN AREAS OF DENSE FOG POSSIBLE MAINLY NORTH OF KMSN AND KMKE TONIGHT WITH PATCHY FOG ALONG AND SOUTH OF THERE. THE CHANCE FOR LIGHT RAIN SHOWERS/DRIZZLE WILL CONTINUE OVER ALL OF SOUTHERN WI THROUGH TONIGHT. VERY SMALL CHANCE FOR THUNDER. EXPECT IMPROVEMENT TO MVFR AND EVENTUALLY VFR AS REGION GETS INTO WARM SECTOR AS WARM FRONT LIFTS INTO CENTRAL WISCONSIN. THIS MAY BE DELAYED UNTIL EARLY WEDNESDAY MORNING. MARINE... ISSUED MARINE DENSE FOG ADVISORY FOR ALL NEARSHORE ZONES DUE A WARM FRONT MOVING NORTHWARD THROUGH LAKE MICHIGAN. WARM MOIST AIR FLOWING OVER THE COOL WATER AND LIGHT EASTERLY WINDS JUST AHEAD OF THE WARM FRONT ARE LEADING TO AREAS OF DENSE FOG OVER THE LAKE. WEB CAMS SHOWED IMPROVEMENT TO VISIBILITIES LATE THIS MORNING IN THE NEARSHORE WATERS WITH RAIN SHOWERS...BUT THEY COULD GO DOWN AGAIN THIS AFTERNOON. THERE IS A GOOD CHANCE FOR AREAS OF DENSE FOG TO PERSIST THROUGH TONIGHT...ESPECIALLY NORTH OF MILWAUKEE. MAY NEED TO EXTEND THE ADVISORY THROUGH TONIGHT. PREV DISCUSSION... /ISSUED 458 AM CDT TUE MAY 28 2013/ TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM WIDESPREAD FOG OVER THE AREA WITH COOL EAST FLOW...SOME PATCHY DENSE FOG BUT MOST VISIBILITIES HOLDING AT 1/2 TO 1 MILE OVER THE FAR WEST AND 1 TO 3 MILES IN THE EAST. WILL MONITOR FOR POSSIBLE ADVISORY IF 1/4 MILE VSBYS BECOME MORE WIDESPREAD. SCATTERED TO BROKEN BAND OF SHOWERS WITH A FEW THUNDERSTORMS OVER FAR SRN SECTIONS OF FORECAST AREA ON NOSE OF INCREASING 850-700 MB WINDS CURRENTLY FOCUSED ON SRN WI BUT EXPECTED TO HEAL OVER TO THE EAST...REFLECTED IN DIMINISHING TREND TO WESTERN END OF LINE. HI-RES/RAPID UPDATE MODELS ALSO TAKE THIS PRECIPITATION OFF TO THE EAST. NORTHERN EDGE OF MCS...RIDING ALONG JUST TO THE NORTH OF SURFACE WARM FRONT AND BEING DRIVEN BY 500 MB SHORT WAVE...WILL CROSS THE FORECAST AREA BETWEEN 12Z AND 18Z. SPC HAS PUSHED SLIGHT RISK FARTHER SOUTH ON 28/06Z DAY 1 VERSUS 27/17Z DAY 2 WITH ONLY THE SOUTHERN-MOST COUNTIES STILL LEFT IN SLIGHT RISK...WITH THAT RISK TIED TO NORTHERN END OF THE CONVECTIVE COMPLEX. STILL EXPECT DECENT RAINS WITH PWS RISING TO 1.5 TO 1.7. COOL OUTFLOW IN THE WAKE OF THE COMPLEX WILL LIKELY HOLD THE EFFECTIVE WARM FRONT TO THE SOUTH UNTIL MID-LATE AFTERNOON. LOW-LEVEL FRONTOGENESIS WITH APPROACHING WARM FRONT...BUT WILL HAVE CHANCE POPS IN THE FORECAST FOR THIS AFTERNOON DUE TO UNCERTAINTY ABOUT STABILIZING AFFECT OF FIRST COMPLEX. BLEND OF MODEL SOLUTIONS BRINGS WARM FRONT INTO THE SRN-MOST COUNTIES AROUND 3 PM...THE I-94 CORRIDOR BETWEEN 4 AND 5 PM AND SLOWS/STALLS NEAR THE NRN COUNTIES AROUND 7 PM BRINGING LATE DAY HIGHS IN THE 60S TO AROUND 70 AWAY FROM THE LAKE. LOWS DO NOT FALL OFF MUCH TONIGHT...WITH LOW TO MID 60S...WITH SLIGHTLY COOLER READINGS NORTH. WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM SHOWER AND THUNDERSTORM CHANCES AND WARM TEMPERATURES ARE EXPECTED THROUGH THE SECOND HALF OF THE WORK WEEK. MODELS CURRENTLY DEPICT A WARM FRONT ACROSS THE NORTHERN FORECAST AREA WEDNESDAY MORNING...LIFTING NORTH THROUGH THE DAY. SHOULD SEE SOME CONVECTION DURING THE DAY AS THIS FRONT HEADS NORTHWARD. LOOKS PRETTY QUIET THEN WEDNESDAY NIGHT AS A WARMER AND SOMEWHAT DRIER AIRMASS PUSHES INTO THE FORECAST AREA...WITH THE LOW LEVEL JET AND ASSOCIATED CONVECTION REMAINING MAINLY TO THE WEST. DID KEEP SOME POPS DUE TO GENERAL UNCERTAINTY...THE HIGHEST IN THE WEST TOWARD THE DEEPER MOISTURE AND STRONGER LOW LEVEL FLOW. LOW PRESSURE OVER THE DAKOTAS WILL REMAIN NEARLY STATIONARY THURSDAY...WHILE A SHORTWAVE APPROACHES DURING THE DAY AND THE LOW LEVEL JET SLIDES EAST INTO THE FORECAST AREA. THE SHORTWAVE WILL THEN MOVE THROUGH DURING THE EVENING AND INTO OVERNIGHT. THIS SETUP SHOULD RESULT IN THE BEST CHANCE OF THUNDERSTORMS THROUGH THE SECOND HALF OF THE WEEK...THUS KEPT LIKELY POPS GOING. INSTABILITY IS NOT PARTICULARLY IMPRESSIVE THURSDAY...WITH SFC BASED CAPE GENERALLY LESS THAN 1000 J/KG VIA NAM AND GFS SOUNDINGS. LOW LEVEL FLOW IS PRETTY GOOD THOUGH...AND 0-6 KM BULK SHEAR IS AROUND 30-40 KT. STORMS COULD THUS BE STRONG TO SEVERE...ESPECIALLY IF THERE IS A BIT MORE SUN THAN CURRENTLY EXPECTED. NEW SPC DAY 3 SEVERE WEATHER OUTLOOK HAS A SLIGHT CHANCE FOR SEVERE STORMS ACROSS THE FORECAST AREA. SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY AS LOW PRESSURE OVER NORTH DAKOTA AND MINNESOTA CONTINUES TO REMAIN NEARLY STATIONARY. SHOWERS AND STORMS ARE THUS LIKELY ONCE AGAIN. THOUGH BETTER LOW LEVEL FLOW WILL BE TO THE SOUTH AND EAST...STRONG TO SEVERE STORMS ARE NOT OUT OF THE QUESTION WITH SIMILAR CAPE VALUES AS THURSDAY...AND WIND SHEAR ACTUALLY A BIT HIGHER. TEMPERATURES WEDNESDAY THROUGH FRIDAY AREA GENERALLY EXPECTED TO BE A FEW DEGREES ABOVE NORMAL. A BIT TRICKY THOUGH...DEPENDING ON HOW QUICK THE WARM FRONT GETS NORTH WEDNESDAY...AND THEN DEPENDING ON TIMING OF SHOWERS AND STORMS AND RESULTANT IMPACT ON TEMPS. PARTICULARLY DIFFICULT NEAR LAKE MICHIGAN...AS MODELS INDICATE WINDS WILL BE SOUTHERLY FOR A GOOD PORTION OF THE TIME. WILL NOT TAKE MUCH FOR THE COOLER LAKE AIRMASS TO INTRUDE INLAND...THOUGH MORE OF A SOUTHWEST COMPONENT TO THE WIND COULD PUSH THE WARMEST TEMPS ALL THE WAY TO THE LAKE. GENERALLY KEPT TEMPS A BIT COOLER NEAR THE LAKE DUE TO THE OVERALL UNCERTAINTY IN WIND DIRECTION AND STRENGTH. SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH SOUTHERN WISCONSIN SATURDAY. COULD SEE SOME SHOWERS AND STORMS AHEAD OF THE FRONT...THE BEST CHANCE TOWARD THE SOUTHEAST. CURRENTLY LOOKS LIKE NEAR NORMAL TEMPS FOR THE FIRST DAY OF JUNE. MAIN UPPER LEVEL WAVE WILL MOVE THROUGH SUNDAY...POSSIBLY BRINGING A FEW SHOWERS. COOLER AIR IS EXPECTED TO ARRIVE WITH THE SHORTWAVE. LOWERED HIGHS A BIT GIVEN COOLER TREND IN THE ECMWF AND GFS AND MAY NEED TO GO A FEW DEGREES LOWER IF THIS TREND CONTINUES. SHOULD BE PLEASANT MONDAY UNDER HIGH PRESSURE...WITH SOME SUNSHINE RETURNING AND TEMPERATURES REMAINING A FEW DEGREES BELOW NORMAL. AVIATION/12Z TAFS/... WILL KEEP IFR CIGS/VSBYS AT TAF LOCATIONS UNTIL PASSAGE OF MCS THROUGH THE REGION LATER THIS MORNING...THEN SLOWLY IMPROVE FROM SOUTH TO NORTH AS WARM FRONT LIFTS THROUGH MID-LATE AFTERNOON. COULD SEE CONVECTION RE-DEVELOP ALONG FRONT...BUT STABILIZING AFFECT OF MORNING COMPLEX UNCERTAIN SO WILL KEEP MENTION OUT AFTER PRECIP WITH COMPLEX ENDS AND SEE HOW ATMOSPHERE RESPONDS. EXPECT IMPROVEMENT TO MVFR AND EVENTUALLY VFR AS REGION GETS INTO WARM SECTOR AS WARM FRONT LIFTS INTO CENTRAL WISCONSIN. MARINE...WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS UNTIL WEDNESDAY AFTERNOON/WEDNESDAY NIGHT. SOUTHWEST TO SOUTH WINDS WILL GUST TO 20 TO 25 KNOTS AT TIMES INTO FRIDAY. LOCATIONS SUCH AS WIND POINT...AND FROM PORT WASHINGTON TO SHEBOYGAN COULD SEE WAVES AROUND 4 FEET OR BETTER WITH THE PERSISTENT SOUTHERLY FETCH BY THURSDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LMZ643>646. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...REM WEDNESDAY THROUGH MONDAY...DDV
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1000 AM CDT TUE MAY 28 2013 .UPDATE... LATEST HRRR AND 12Z NAM ARE NOW KEEPING THE SURFACE WARM FRONT FURTHER SOUTH THAN PREVIOUS RUNS. GIVEN THE MORNING ROUND OF SHOWERS AND STORMS...EFFECTIVE WARM FRONT WILL BE DELAYED IN MOVING NORTHWARD TODAY. MODELS STILL SHOW IT PUSHING INTO FAR SOUTHERN WISCONSIN BY LATE AFTERNOON...BUT THEN HAVING IT STALL THIS EVENING AND BISECT THE MKX FORECAST AREA. CHANCE OF LIGHT SHOWERS/SPRINKLES/DRIZZLE WILL CONTINUE THROUGH TODAY AND ALSO TONIGHT WITH THE VICINITY OF THE WARM FRONT...BUT ANY STORMS DEVELOPING IN THE REGION ARE EXPECTED TO STAY SOUTH OF THE WI/IL BORDER THROUGH LATE TONIGHT. THE LOW LEVEL JET IS JUST BARELY OVER SOUTHERN WI TODAY...BUT GENERALLY POINTING TOWARD LOWER MICHIGAN. LEFT THE SLIGHT CHANCE FOR THUNDER IN THE FORECAST FOR NOW GIVEN SOME ELEVATED CAPE. HEADLINE POTENTIAL FOR TONIGHT WILL BE DENSE FOG. WITH LIGHT EASTERLY FLOW AT THE SURFACE ON THE NORTH SIDE OF THE WARM FRONT...AREAS OF FOG ARE EXPECTED AND COULD BECOME DENSE. BEST CHANCE FOR DENSE FOG WOULD BE THE NORTH HALF OF THE MKX FORECAST AREA. && .AVIATION/18Z TAFS/... THE WARM FRONT AND HIGHER CEILINGS ARE JUST SOUTH OF THE WI/IL BORDER...BUT NOT EXPECTING THAT FRONT TO MOVE NORTHWARD QUICKLY TODAY OR TONIGHT. KENW AND KJVL COULD SCOUR OUT THE LIFR CIGS BY MIDDAY...BUT KMSN/KUES/KMKE WILL LIKELY REMAIN LIFR/IFR THROUGH MOST OF TONIGHT. PATCHY FOG EXPECTED ACROSS MUCH OF THE SOUTHERN WI TODAY...THEN AREAS OF DENSE FOG POSSIBLE MAINLY NORTH OF KMSN AND KMKE TONIGHT WITH PATCHY FOG ALONG AND SOUTH OF THERE. THE CHANCE FOR LIGHT RAIN SHOWERS/DRIZZLE WILL CONTINUE OVER ALL OF SOUTHERN WI THROUGH TONIGHT. VERY SMALL CHANCE FOR THUNDER. EXPECT IMPROVEMENT TO MVFR AND EVENTUALLY VFR AS REGION GETS INTO WARM SECTOR AS WARM FRONT LIFTS INTO CENTRAL WISCONSIN. THIS MAY BE DELAYED UNTIL EARLY WEDNESDAY MORNING. && .MARINE... ISSUED MARINE DENSE FOG ADVISORY FOR ALL NEARSHORE ZONES DUE A WARM FRONT MOVING NORTHWARD THROUGH LAKE MICHIGAN. WARM MOIST AIR FLOWING OVER THE COOL WATER AND LIGHT EASTERLY WINDS JUST AHEAD OF THE WARM FRONT ARE LEADING TO AREAS OF DENSE FOG OVER THE LAKE. WEB CAMS SHOWED IMPROVEMENT TO VISIBILITIES LATE THIS MORNING IN THE NEARSHORE WATERS WITH RAIN SHOWERS...BUT THEY COULD GO DOWN AGAIN THIS AFTERNOON. THERE IS A GOOD CHANCE FOR AREAS OF DENSE FOG TO PERSIST THROUGH TONIGHT...ESPECIALLY NORTH OF MILWAUKEE. MAY NEED TO EXTEND THE ADVISORY THROUGH TONIGHT. && .PREV DISCUSSION... /ISSUED 458 AM CDT TUE MAY 28 2013/ TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM WIDESPREAD FOG OVER THE AREA WITH COOL EAST FLOW...SOME PATCHY DENSE FOG BUT MOST VISIBILITIES HOLDING AT 1/2 TO 1 MILE OVER THE FAR WEST AND 1 TO 3 MILES IN THE EAST. WILL MONITOR FOR POSSIBLE ADVISORY IF 1/4 MILE VSBYS BECOME MORE WIDESPREAD. SCATTERED TO BROKEN BAND OF SHOWERS WITH A FEW THUNDERSTORMS OVER FAR SRN SECTIONS OF FORECAST AREA ON NOSE OF INCREASING 850-700 MB WINDS CURRENTLY FOCUSED ON SRN WI BUT EXPECTED TO HEAL OVER TO THE EAST...REFLECTED IN DIMINISHING TREND TO WESTERN END OF LINE. HI-RES/RAPID UPDATE MODELS ALSO TAKE THIS PRECIPITATION OFF TO THE EAST. NORTHERN EDGE OF MCS...RIDING ALONG JUST TO THE NORTH OF SURFACE WARM FRONT AND BEING DRIVEN BY 500 MB SHORT WAVE...WILL CROSS THE FORECAST AREA BETWEEN 12Z AND 18Z. SPC HAS PUSHED SLIGHT RISK FARTHER SOUTH ON 28/06Z DAY 1 VERSUS 27/17Z DAY 2 WITH ONLY THE SOUTHERN-MOST COUNTIES STILL LEFT IN SLIGHT RISK...WITH THAT RISK TIED TO NORTHERN END OF THE CONVECTIVE COMPLEX. STILL EXPECT DECENT RAINS WITH PWS RISING TO 1.5 TO 1.7. COOL OUTFLOW IN THE WAKE OF THE COMPLEX WILL LIKELY HOLD THE EFFECTIVE WARM FRONT TO THE SOUTH UNTIL MID-LATE AFTERNOON. LOW-LEVEL FRONTOGENESIS WITH APPROACHING WARM FRONT...BUT WILL HAVE CHANCE POPS IN THE FORECAST FOR THIS AFTERNOON DUE TO UNCERTAINTY ABOUT STABILIZING AFFECT OF FIRST COMPLEX. BLEND OF MODEL SOLUTIONS BRINGS WARM FRONT INTO THE SRN-MOST COUNTIES AROUND 3 PM...THE I-94 CORRIDOR BETWEEN 4 AND 5 PM AND SLOWS/STALLS NEAR THE NRN COUNTIES AROUND 7 PM BRINGING LATE DAY HIGHS IN THE 60S TO AROUND 70 AWAY FROM THE LAKE. LOWS DO NOT FALL OFF MUCH TONIGHT...WITH LOW TO MID 60S...WITH SLIGHTLY COOLER READINGS NORTH. WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM SHOWER AND THUNDERSTORM CHANCES AND WARM TEMPERATURES ARE EXPECTED THROUGH THE SECOND HALF OF THE WORK WEEK. MODELS CURRENTLY DEPICT A WARM FRONT ACROSS THE NORTHERN FORECAST AREA WEDNESDAY MORNING...LIFTING NORTH THROUGH THE DAY. SHOULD SEE SOME CONVECTION DURING THE DAY AS THIS FRONT HEADS NORTHWARD. LOOKS PRETTY QUIET THEN WEDNESDAY NIGHT AS A WARMER AND SOMEWHAT DRIER AIRMASS PUSHES INTO THE FORECAST AREA...WITH THE LOW LEVEL JET AND ASSOCIATED CONVECTION REMAINING MAINLY TO THE WEST. DID KEEP SOME POPS DUE TO GENERAL UNCERTAINTY...THE HIGHEST IN THE WEST TOWARD THE DEEPER MOISTURE AND STRONGER LOW LEVEL FLOW. LOW PRESSURE OVER THE DAKOTAS WILL REMAIN NEARLY STATIONARY THURSDAY...WHILE A SHORTWAVE APPROACHES DURING THE DAY AND THE LOW LEVEL JET SLIDES EAST INTO THE FORECAST AREA. THE SHORTWAVE WILL THEN MOVE THROUGH DURING THE EVENING AND INTO OVERNIGHT. THIS SETUP SHOULD RESULT IN THE BEST CHANCE OF THUNDERSTORMS THROUGH THE SECOND HALF OF THE WEEK...THUS KEPT LIKELY POPS GOING. INSTABILITY IS NOT PARTICULARLY IMPRESSIVE THURSDAY...WITH SFC BASED CAPE GENERALLY LESS THAN 1000 J/KG VIA NAM AND GFS SOUNDINGS. LOW LEVEL FLOW IS PRETTY GOOD THOUGH...AND 0-6 KM BULK SHEAR IS AROUND 30-40 KT. STORMS COULD THUS BE STRONG TO SEVERE...ESPECIALLY IF THERE IS A BIT MORE SUN THAN CURRENTLY EXPECTED. NEW SPC DAY 3 SEVERE WEATHER OUTLOOK HAS A SLIGHT CHANCE FOR SEVERE STORMS ACROSS THE FORECAST AREA. SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY AS LOW PRESSURE OVER NORTH DAKOTA AND MINNESOTA CONTINUES TO REMAIN NEARLY STATIONARY. SHOWERS AND STORMS ARE THUS LIKELY ONCE AGAIN. THOUGH BETTER LOW LEVEL FLOW WILL BE TO THE SOUTH AND EAST...STRONG TO SEVERE STORMS ARE NOT OUT OF THE QUESTION WITH SIMILAR CAPE VALUES AS THURSDAY...AND WIND SHEAR ACTUALLY A BIT HIGHER. TEMPERATURES WEDNESDAY THROUGH FRIDAY AREA GENERALLY EXPECTED TO BE A FEW DEGREES ABOVE NORMAL. A BIT TRICKY THOUGH...DEPENDING ON HOW QUICK THE WARM FRONT GETS NORTH WEDNESDAY...AND THEN DEPENDING ON TIMING OF SHOWERS AND STORMS AND RESULTANT IMPACT ON TEMPS. PARTICULARLY DIFFICULT NEAR LAKE MICHIGAN...AS MODELS INDICATE WINDS WILL BE SOUTHERLY FOR A GOOD PORTION OF THE TIME. WILL NOT TAKE MUCH FOR THE COOLER LAKE AIRMASS TO INTRUDE INLAND...THOUGH MORE OF A SOUTHWEST COMPONENT TO THE WIND COULD PUSH THE WARMEST TEMPS ALL THE WAY TO THE LAKE. GENERALLY KEPT TEMPS A BIT COOLER NEAR THE LAKE DUE TO THE OVERALL UNCERTAINTY IN WIND DIRECTION AND STRENGTH. SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH SOUTHERN WISCONSIN SATURDAY. COULD SEE SOME SHOWERS AND STORMS AHEAD OF THE FRONT...THE BEST CHANCE TOWARD THE SOUTHEAST. CURRENTLY LOOKS LIKE NEAR NORMAL TEMPS FOR THE FIRST DAY OF JUNE. MAIN UPPER LEVEL WAVE WILL MOVE THROUGH SUNDAY...POSSIBLY BRINGING A FEW SHOWERS. COOLER AIR IS EXPECTED TO ARRIVE WITH THE SHORTWAVE. LOWERED HIGHS A BIT GIVEN COOLER TREND IN THE ECMWF AND GFS AND MAY NEED TO GO A FEW DEGREES LOWER IF THIS TREND CONTINUES. SHOULD BE PLEASANT MONDAY UNDER HIGH PRESSURE...WITH SOME SUNSHINE RETURNING AND TEMPERATURES REMAINING A FEW DEGREES BELOW NORMAL. AVIATION/12Z TAFS/... WILL KEEP IFR CIGS/VSBYS AT TAF LOCATIONS UNTIL PASSAGE OF MCS THROUGH THE REGION LATER THIS MORNING...THEN SLOWLY IMPROVE FROM SOUTH TO NORTH AS WARM FRONT LIFTS THROUGH MID-LATE AFTERNOON. COULD SEE CONVECTION RE-DEVELOP ALONG FRONT...BUT STABILIZING AFFECT OF MORNING COMPLEX UNCERTAIN SO WILL KEEP MENTION OUT AFTER PRECIP WITH COMPLEX ENDS AND SEE HOW ATMOSPHERE RESPONDS. EXPECT IMPROVEMENT TO MVFR AND EVENTUALLY VFR AS REGION GETS INTO WARM SECTOR AS WARM FRONT LIFTS INTO CENTRAL WISCONSIN. MARINE...WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS UNTIL WEDNESDAY AFTERNOON/WEDNESDAY NIGHT. SOUTHWEST TO SOUTH WINDS WILL GUST TO 20 TO 25 KNOTS AT TIMES INTO FRIDAY. LOCATIONS SUCH AS WIND POINT...AND FROM PORT WASHINGTON TO SHEBOYGAN COULD SEE WAVES AROUND 4 FEET OR BETTER WITH THE PERSISTENT SOUTHERLY FETCH BY THURSDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LMZ643>646. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...REM WEDNESDAY THROUGH MONDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1122 PM CDT MON MAY 27 2013 .UPDATE... ISSUED AT 850 PM CDT MON MAY 27 2013 THE NEAR TERM FOCUS REMAINS ON THE FLOODING POTENTIAL OVERNIGHT INTO TUESDAY AS THE NEXT ROUND OF RAIN MOVES IN. CURRENTLY...A LEFT OVER MESOSCALE CONVECTIVE VORTEX HAS STALLED OUT ACROSS SOUTHEAST MINNESOTA WITH A BAND OF LIGHT TO MODERATE RAIN AND DRIZZLE OCCURRING NEAR IT. THE MAIN BAND EXTENDS FROM SOUTHEAST MINNESOTA THROUGH CENTRAL WISCONSIN AND THEN DOWN THROUGH SOUTHERN LAKE MICHIGAN TO THE MORE POTENT PART OF THE SYSTEM. GIVEN THE STALLED OUT PATTERN...AM NOT EXPECTING MUCH IN THE WAY OF DIMINISHMENT OF THIS FEATURE OVERNIGHT...SO WILL KEEP THE PRECIPITATION CHANCES UP ACROSS THIS REGION. THE FOCUS THEN GOES TO THE SOUTH WHERE CONVECTION IS EXPECTED TO DEVELOP ALONG THE NOSE OF THE 850MB MOISTURE TRANSPORT WHICH CURRENTLY IS ALIGNED ALONG THE IOWA/MISSOURI BORDER. NOT OVERLY CONFIDENT IN HOW THINGS WILL TRANSPIRE OVERNIGHT...BUT THE PAST FEW RUNS OF THE RAP AND HRRR HAVE ADVECTED THIS NOSE OF THE MOISTURE TRANSPORT NORTHWARD INTO CENTRAL IOWA AFTER 6Z WITH THE MAIN BAND OF CONVECTION TRACKING THAT WAY AS WELL. AN ADDITIONAL BOOST IN LIFT COMES IN BEFORE 12Z AS A MID LEVEL SHORT WAVE TROUGH CATCHES UP TO THIS LOW LEVEL MOISTURE TRANSPORT. BOTH THE 28.00Z RAP & HRRR INCREASE THE 0-3KM MUCAPE UP TO AROUND 1000 J/KG INTO NORTHEAST IOWA...SO THE CHANCES FOR THUNDER ARE STILL PRETTY DECENT THERE. GIVEN THIS SCENARIO...THE POTENTIAL FOR FLASH FLOODING IS STILL THERE...PARTICULARLY FOR NORTHEAST IOWA AND NOT SO MUCH FOR SOUTHEAST MINNESOTA. ANOTHER FEATURE THAT COULD AFFECT THIS PATTERN IS WITH THE MCS THAT HAS DEVELOPED SOUTHWEST OF OMAHA THAT COULD KEEP THE STRONGER MOISTURE ADVECTION FURTHER TO THE SOUTH ALONG THE SURFACE WARM FRONT. AT THIS POINT...WILL NOT BE MAKING ANY CHANGES TO THE FLASH FLOOD WATCH...BUT WILL CONTINUE TO HIGHLIGHT THE SLIGHTLY HIGHER POTENTIAL FOR FLOODING IN NORTHEAST IOWA. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 320 PM CDT MON MAY 27 2013 REMAINS OF LAST NIGHT RAINS IS STILL MOVING SLOWLY NORTH/NORTHEAST ACROSS THE AREA. STILL EXPECT SOME OF THIS RAIN TO BE AROUND AT 00Z AND THIS IS CONFIRMED BY THE 27.17Z HRRR. SURFACE ANALYSIS THIS AFTERNOON SHOWS TWO BOUNDARIES SOUTH OF THE FORECAST AREA. A WEAK WARM FRONT/WIND SHIFT LINE EXTENDS FROM NORTHWEST IOWA INTO NORTHERN ILLINOIS. A MUCH STRONGER WARM FRONT LIES ACROSS CENTRAL MISSOURI. ALL THE 27.12Z MODELS BRING THE SHORT WAVE TROUGH OVER EASTERN COLORADO NORTHEAST ACROSS THE AREA OVERNIGHT AND TUESDAY MORNING. THE NAM SHOWS THIS WAVE PRODUCING UP TO 4 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER. THE LIFT FROM THE WAVE SHOULD BE ENHANCED BY SOME AGEOSTROPHIC MOTIONS AS THE LEFT EXIT REGION OF THE JET MOVES OVER THE AREA LATE TONIGHT. WITH THE MAIN WARM FRONT STILL WELL SOUTH OF THE AREA...THE MAIN AREA OF MOISTURE TRANSPORT SHOULD NOT GET AS FAR NORTH AS PREVIOUSLY EXPECTED. THE MODELS NOW SHOW THE NOSE OF THIS COMING INTO SOUTHERN AND CENTRAL IOWA WHICH IS WHERE THE BEST ISENTROPIC UP GLIDE WILL BE. EXPECT THAT THE NEXT CONVECTIVE COMPLEX WILL DEVELOP ON THE NOSE OF THIS MOISTURE TRANSPORT THIS EVENING AND GRADUALLY WORK NORTH/NORTHEAST INTO THE AREA WITH THE BEST CHANCES FOR RAIN SOUTH OF THE IOWA/MINNESOTA BORDER. STILL GOOD INGREDIENTS IN PLACE FOR THE STORMS TO BE EFFICIENT RAIN PRODUCERS WITH WARM CLOUD DEPTHS AROUND 3.5 KM AND PRECIPITABLE WATERS AROUND 1.5 INCHES. THE COMPLEX THAT FORMS IS EXPECTED TO PRIMARILY IMPACT THE SOUTHERN SECTIONS OF THE AREA TONIGHT AND THEN MOVE NORTHEAST THROUGH THE EASTERN SECTIONS TUESDAY MORNING AND AFTERNOON. BECAUSE OF THIS CONVECTION...THE WARM FRONT IS NOT EXPECTED TO MOVE MUCH TUESDAY STAYING JUST TO THE SOUTH OF THE FORECAST AREA. WITH THE CLOUDS...RAIN AND WARMER AIR STAYING SOUTH OF THE AREA...SIGNIFICANTLY CUT TEMPERATURES AND CONCERNED THAT THESE MAY STILL BE TOO WARM. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 320 PM CDT MON MAY 27 2013 ONCE THE WAVE MOVES BY TUESDAY...THE UPPER LEVEL RIDGE OVER THE ATLANTIC WILL BEGIN AMPLIFYING AND AN UPPER LEVEL LOW WILL START TO FORM OVER THE CENTRAL ROCKIES. THIS WILL CAUSE THE FLOW TO BECOME MORE SOUTHWEST OVER THE CENTRAL PART OF THE COUNTRY. STILL EXPECTING SEVERAL SHORT WAVE TROUGHS TO BE EMBEDDED IN THIS FLOW...BUT CONFIDENCE ON WHERE THESE WILL TRACK IS NOT VERY HIGH AS THEY COULD MOVE OVER THE AREA OR STAY OFF TO THE WEST. ONCE THIS PATTERN SETS UP...IT IS EXPECTED TO REMAIN THROUGH THURSDAY AS THE DOWN STREAM RIDGING BLOCKS OFF ANY EASTWARD MOVEMENT OF THE UPPER LEVEL LOW. THE SURFACE WARM FRONT SHOULD GET LIFTED NORTH THROUGH THE AREA IN THIS MORE AMPLIFIED SOUTHWEST FLOW EITHER TUESDAY NIGHT OR MORE LIKELY WEDNESDAY. HAVE THUS CUT BACK ON LOW TEMPERATURES FOR TUESDAY NIGHT BEFORE SHOWING THE WARM AIR ARRIVING FOR WEDNESDAY. AS FOR THE RAIN CHANCES...MAY BE SOMEWHAT OF BREAK IN THE ACTION TUESDAY NIGHT BEFORE A LINE OF CONVECTION FORMS ON THE FRONT WEDNESDAY LIFTING NORTH ACROSS THE AREA WITH ANOTHER POSSIBLE LULL IN THE ACTION WEDNESDAY NIGHT. IF THE MODELS ARE CORRECT ON TIMING...A HEALTHY SHORT WAVE TROUGH SHOULD BE COMING ACROSS THE AREA THURSDAY AND WILL TRY TO PUSH A COLD FRONT TOWARD THE REGION FROM THE WEST. ONCE THE WARM FRONT MOVES THROUGH...WILL ACTUALLY HAVE THE CHANCE FOR SOME CAPE TO BUILD OVER THE AREA...BUT HOW MUCH REMAINS UNCERTAIN. BETWEEN 1500 AND 2000 J/KG OF SB CAPE COULD DEVELOP WEDNESDAY AFTERNOON AND THURSDAY IF THE AREA CAN STAY FREE OF RAIN AND POSSIBLY SEE A LITTLE BIT OF SUNSHINE. SHEAR OF 25 TO 35 KNOTS LOOKS TO BE CONFINED TO THE 0-3 KM LAYER SO IF THERE IS AN OPPORTUNITY FOR SEVERE STORMS TO DEVELOP...LOOKS LIKE THE THREATS WOULD BE HAIL AND WINDS. THE EXTENDED RANGE MODELS ALL ARE IN AGREEMENT IN SHOWING THE UPPER LEVEL LOW OVER THE HIGH PLAINS WILL BEGIN TO OPEN UP INTO AN OPEN WAVE AND TAKE ON A POSITIVE TILT BY THE END OF THE WEEK. AS THIS OCCURS...THE DOWN STREAM RIDGE OVER THE EASTERN ATLANTIC IS EXPECTED TO FLATTEN ENOUGH TO ALLOW THE SYSTEM TO BEGIN PROGRESSING EAST/NORTHEAST AND FINALLY CLEAR THE UPPER MIDWEST OVER THE WEEKEND. THE MAIN SURFACE LOW IS EXPECTED TO BE OVER THE DAKOTAS WITH THE WARM FRONT WELL TO THE NORTH OF THE REGION AND COLD FRONT WELL OFF TO THE WEST. THIS WILL PUT THE AREA IN THE WARM SECTOR WITH THE PERIODIC RAIN CHANCES CONTINUING WITH WAVES EXPECTED TO STILL BE ROTATING AROUND THE UPPER LEVEL SYSTEM. THE RAIN CHANCES WILL CONTINUE UNTIL THE COLD FRONT MOVES THROUGH EITHER FRIDAY NIGHT OR SATURDAY WITH SOME POTENTIAL FOR SOME LINGERING WRAP AROUND RAIN INTO SATURDAY NIGHT OR SUNDAY BEFORE HIGH PRESSURE FINALLY STARTS TO BUILD IN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1122 PM CDT MON MAY 27 2013 IFR TO LOW END MVFR CONDITIONS WILL CONTINUE THROUGHOUT THE REGION OVERNIGHT ON INTO TUESDAY NIGHT. WITH A WARM FRONT EXPECTED TO STAY SOUTH OF THE REGION...LOW LEVEL MOISTURE WILL REMAIN POOLED ALONG THE NORTHERN PERIPHERY OF IT AND CAUSE THE LOW CEILINGS AND VISIBILITIES TO CONTINUE. SOME OF THE FORECAST MODELS ARE SHOWING THE NEXT ROUND OF RAIN SHOWERS MOVING IN LATER THIS MORNING AS A SYSTEM TRACKS ACROSS IOWA. THIS FEATURE MAY HELP TO START A TREND OF SLOWLY IMPROVING CONDITIONS WITH SOME POTENTIALLY DRIER AIR GETTING PULLED IN BEHIND IT. STILL EXPECTING CONDITIONS TO BE IFR TO MVFR THROUGH MUCH OF THE PERIOD HOWEVER. && .HYDROLOGY... ISSUED AT 320 PM CDT MON MAY 27 2013 CONFIDENCE OF THE POTENTIAL FOR FLOODING HAS DECREASED TODAY WITH THE MAIN BAND OF ACTIVITY NOW EXPECTED TO STAY FARTHER SOUTH THAN ANTICIPATED AT THIS TIME SUNDAY. NOW EXPECTING AMOUNTS TO BE UNDER AN INCH BOTH TONIGHT AND TUESDAY WITH THE HEAVIEST AMOUNTS ACROSS NORTHEAST IOWA AND SOUTHWEST MINNESOTA WHERE LOCALLY HIGHER AMOUNTS COULD PUSH TOTALS UP TO TWO INCHES. NOT MAKING ANY CHANGES TO THE FLASH FLOOD WATCH AT THIS TIME AS WILL LET TONIGHTS CONVECTION PLAY OUT AND THEN MAY ADJUSTMENTS IN AREAL COVERAGE AND TIME AS NEEDED. HAVE ALSO ISSUED A FLOOD WATCH FOR THE TURKEY RIVER ACROSS CLAYTON COUNTY AS HIGHER RAINFALL TOTALS COULD PUSH IT TO FLOOD STAGE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR IAZ008>011-018-019- 029-030. && $$ UPDATE...HALBACH SHORT TERM...04 LONG TERM...04 AVIATION...HALBACH HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
320 AM EDT Thu May 30 2013 .NEAR TERM [Through Tonight]... At upper levels, we see a negatively tilted trough over the central part of the nation and a ridge over much of the Southeast. Surface analysis continues to show a ridge axis extending from off the Carolina coast westward to East Texas. We have seen a very gradual moistening of the lower levels over the past few days with some isolated to scattered showers and thunderstorms finally developing along the inland moving sea breeze on Wednesday. We believe we will see similar development today. PoPs will be based on a blend of sea breeze climatology for a type 7 day (strong southeast flow) and local confidence and CAM guidance. We have continued the recent trend of going a degree or two above a guidance blend for max temps, and even more than that for the VLD area. Winds should stay up enough to once again preclude any fog formation, although if any place was to see it, it would be the Tallahassee metro area. Min temps will be 2-4 degrees above normal, generally ranging from the upper 60s north to the lower 70s for the coastal zones. && .SHORT TERM [Friday Through Saturday]... We are still only expecting generally subtle changes to both the Upper level and Lower level patterns over the course of the short term period, with weak ridging continuing aloft, with the surface high pressure system lingering to the east of the Carolinas. However, with the southeasterly flow persisting (albeit gradually weakening at the lower levels) deep layer moisture is expected to continue to increase. Precipitable water values in the forecast soundings may exceed 1.75 inches in many areas by the end of the day on Saturday, which should allow the Sea Breeze Front to become more efficient at producing mainly afternoon and evening showers and thunderstorms over the interior, and the nighttime Land Breeze to produce more convection over the Coastal Waters. Therefore, went above all available guidance for PoPs on both days (save the always extremely high SREF), with inland rain chances ranging from 20 to 40 percent on Friday, and 40 to 50 percent on Saturday. Despite the increase in PoPs, high and low temps are expected to remain a bit above climo, with highs ranging from the mid 80s along the coast to the lower 90s further inland. Low temps will range from the upper 60s, to the lower 70s from the interior to the coast. && .LONG TERM [Saturday Night through Tuesday]... The large scale longwave pattern commences with ridging over Wrn, troughing over Cntrl to Appalachians/Wrn Gulf ridging Ewd into Wrn Atlc. At the surface, high Wrn Atlc with ridge Ewd across Nrn gulf region. Low over Nrn Great Lakes with cold front SSW across TN Valley into TX. During the rest of the period, Cntrl trough will continue pushing Ewd with axis down Ern Gulf Sun night or Mon with ECMWF quickest in movement. Cold front pushed SEWD with weakening and retreating ridge but with again some model disagreement. Some models like GFS stall it along Nrn gulf coast others like ECMWF bring it across our area Mon into Mon night with veering winds and an increase in rain Sun into Mon. As trough/front push offshore, upstream ridge begins to overspread region Tues. Also by Monday, both the GFS and ECMWF develop a surface wave near the Yucatan Peninsula with some indication that this low will develop NEWD into the Gulf of Mex. but it is far too early to determine the track or intensity of this possible feature. Seasonable temperatures should occur throughout the period, with highs generally in the low 90s and lows in the mid- upper 60s. && .AVIATION [Through 06 UTC Friday] The NARRE and HRRR guidance once again support the gridded LAMP and MOS in showing low ceilings developing overnight across most of the area. We show a few hours of MVFR at the terminals, not quite as low as guidance, but similar to what happened yesterday. Visibility restrictions are not anticipated as surface winds are forecast to remain around 5-9 kt through the night. One possible exception is the TLH vicinity which received the bulk of the showers and storms last evening. We indicate some restriction there, but not below the ceiling category. Isolated to scattered shower and thunderstorm development is expected once again this afternoon. However, coverage is not expected to be sufficient for tempo groups and convection was only mentioned in the vicinity of area terminals. && .MARINE... A ridge of high pressure to the east of the Carolinas will continue to provide favorable conditions for mainly nocturnal wind surges out of the southeast through Saturday. Winds speeds will continue to reach the Cautionary range, with a few areas near Small Craft Advisory levels through tonight and into Friday morning. The pressure pattern is expected to weaken and break down by later on Saturday and very clearly by Sunday, with afternoon wind speeds around 10 knots anticipated by Sunday afternoon. && .FIRE WEATHER... RH will be insufficiently low to reach red flag criteria for the foreseeable future. However, dispersion indices will remain elevated, over 75 across most areas today and again on Friday. && .HYDROLOGY... Isolated to scattered showers and thunderstorms are expected over the next several days, and though a few locations could receive locally heavy rainfall, no significant impacts are anticipated on our area rivers. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 91 70 91 69 91 / 40 10 30 20 50 Panama City 88 73 87 73 87 / 30 20 30 20 50 Dothan 92 68 91 69 92 / 30 20 30 20 40 Albany 91 68 92 67 92 / 10 10 30 20 40 Valdosta 93 67 93 67 92 / 20 10 20 20 40 Cross City 93 67 92 67 92 / 30 20 30 20 50 Apalachicola 87 72 85 73 85 / 30 20 30 20 40 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Wool SHORT TERM...Gould LONG TERM...Block AVIATION...Wool MARINE...Gould FIRE WEATHER...Wool HYDROLOGY...Gould
AREA FORECAST DISCUSSION
NWS MIAMI FL
238 AM EDT THU MAY 30 2013 .SHORT TERM (TODAY THROUGH SATURDAY)... THE GLOBAL MODELS CONTINUE TO STRUGGLE WITH THE OVERALL SURFACE SYNOPTIC PATTERN IN THIS PERIOD BUT ARE IN AGREEMENT THAT THE MID LEVEL PRESSURE PATTERN WILL REMAIN QUITE WEEK ACROSS SOUTH FLORIDA. THE GFS, ECMWF AND NAM ALL SHOW A WEAK 500 MB TROUGH DEVELOPING EAST OF THE PENINSULA ON FRIDAY AND SATURDAY DRIFTING IT TO THE NORTHEAST. THIS COULD ALLOW FOR SOME SLIGHT DRYING ALOFT AS DRIER AIR MOVES SOUTHWARD ON THE WEST SIDE OF THE TROUGH. THIS IS REFLECTED IN THE LATEST POP GUIDANCE FROM BOTH THE MET AND MAV WHICH SHOW A TREND WITH LOWER NUMBERS AFTER TODAY. THE NAM AND GFS HAVE COME MORE IN LINE AT THE SURFACE IN DEVELOPING A WEAK INVERTED TROUGH OVER THE FLORIDA STRAITS ON FRIDAY AND DRIFTING IT TO THE NORTH ON SATURDAY WHICH LESSENS THE LOW LEVEL SOUTHEAST WIND FLOW SIGNIFICANTLY. THE ECMWF DOES NOT SHOW THIS FEATURE MAINTAINING AN ONSHORE FLOW ALONG THE SOUTHEAST COAST ALTHOUGH IN A WEAKENED STATE AS IT SHOWS THE RIDGE TO THE NORTH WEAKENING. THE NAM HAS INITIALIZED THE BEST COMPARING IT TO CURRENT OBSERVATIONS FROM THE C-MAN STATIONS BUT THE QUESTION WILL THE WEAK TROUGH DEVELOP AS FORECAST FROM THE NAM AND GFS. EVEN THOUGH THE NAM AND GFS HAVE BEEN CONSISTENT IN FORECASTING THIS TROUGH, THEY HAVE BEEN VERY INCONSISTENT IN ITS TIMING. THEREFORE, WILL LEAN TOWARDS THE NAM EARLY IN THE PERIOD BUT THEN GO MORE WITH THE ECMWF FOR FRIDAY NIGHT AND SATURDAY. THE OTHER FACTOR IN THE SHORT TERM IS THE AMOUNT OF RAINFALL THAT IS POSSIBLE. MOST OF THE RAIN THE PAST FEW DAYS HAS BEEN CONCENTRATED OVER THE EASTERN HALF OF THE SOUTHERN PENINSULA WITH VERY SATURATED GROUNDS FROM PERSISTENT RAIN PERIODS SINCE APRIL. GIVEN THE ONGOING ONSHORE FLOW OF MOIST AND UNSTABLE AIR AND SCATTERED SHOWERS, THE FLOOD WATCH WILL CONTINUE THROUGH 12Z FRIDAY. THE LATEST RUN OF THE HRRR WHICH TYPICALLY DOES QUITE WELL DOES NOT SHOW MUCH ACTIVITY THROUGH EARLY THURSDAY. HOWEVER, WITH VERY LITTLE CHANGE IN THIS PATTERN AT LEAST THROUGH THURSDAY NIGHT THE SHOWER ACTIVITY COULD DEVELOP AT ANY TIME AND MOVE ONSHORE WITHIN THE FLOOD WATCH BOX. .LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... BOTH THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING A MID LEVEL TROUGH DEEPENING ACROSS THE EASTERN U.S. MAINTAINING A RIDGE TO THE WEST AND A WEAK PRESSURE PATTERN ACROSS SOUTH FLORIDA. AT THE SURFACE, BOTH MODELS COME MORE IN LINE WITH A LIGHTER SOUTHEAST FLOW AS THE RIDGE WEAKENS AND SHIFTS TO THE EAST AS A WEAK COLD FRONT MOVES INTO THE SOUTHEAST STATES. HOWEVER, THE GFS THEN DEVELOPS A STRONGER SURFACE TROUGH OVER THE GULF STATES LATE IN THE PERIOD AND VEERS THE WIND ACROSS SOUTH FLORIDA TO THE SOUTHWEST. BEING THIS LATE IN THE FORECAST, WILL NOT JUMP ON THAT AND WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH THE ENTIRE EXTENDED PERIOD. && .AVIATION... BERMUDA HIGH CONTINUES TO BRING STRONG EASTERLY FLOW AND RAIN SHOWERS TO SOUTH FLORIDA THROUGH THE TAF PERIOD. THERE IS A LULL IN PRECIPITATION THIS MORNING THAT SHOULD COME TO AN END AFTER SUNRISE. THE RAIN MAY BE HEAVY AT TIMES, REDUCING FLIGHT CATEGORIES TO MVFR AND IFR FOR SHORT PERIODS OF TIME. HOWEVER, WITH SUCH GREAT UNCERTAINTY AS TO WHEN AND WHERE THEY WILL OCCUR, HAVE NOT REFLECTED THE REDUCTIONS IN THE TAFS AT THIS TIME. WINDS WILL BE GUSTY ONCE AGAIN TODAY. THERE IS SOME INDICATION IN THE MODELS THAT WINDS AND PRECIPITATION MAY SETTLE DOWN FOR AT LEAST WHILE LATE THIS EVENING AND POSSIBLY OVERNIGHT TONIGHT. BUT, CONFIDENCE IS LOW ON THIS AT THIS TIME. && .MARINE... ROUGH MARINE CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY FRIDAY. MODEL GUIDANCE HINTS AT SOME WEAKENING IN THE GRADIENT FLOW LATE FRIDAY INTO THE WEEKEND WITH CALMER WIND AND SEAS. JUST HOW MUCH WEAKENING DEPENDS ON THE RAPIDNESS OF THE SLACKENING GRADIENT WITH TIME. FOR NOW, HAVE KEPT A SOUTHEAST FLOW WITH SUBSIDING SPEEDS AS HIGH PRESSURE RETREATS TO THE EAST. && .FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 84 77 86 76 / 60 30 50 40 FORT LAUDERDALE 83 76 85 77 / 70 40 50 40 MIAMI 83 75 87 76 / 70 40 50 40 NAPLES 89 72 89 74 / 60 30 40 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...FLOOD WATCH THROUGH FRIDAY MORNING FOR COASTAL BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND BROWARD-INLAND MIAMI DADE-INLAND PALM BEACH-METRO BROWARD- METRO MIAMI DADE-METRO PALM BEACH. RIP CURRENT RISK THROUGH FRIDAY AFTERNOON FOR COASTAL BROWARD- COASTAL MIAMI DADE-COASTAL PALM BEACH. AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM. GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM- COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING FROM 20 TO 60 NM. && $$ DISCUSSION/MARINE/FIRE...30/KOB AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
132 AM EDT THU MAY 30 2013 .PREV DISCUSSION... /ISSUED 800 PM EDT WED MAY 29 2013/ UPDATE... NO CHANGES PLANNED FOR THE FORECAST EXCEPT SOME MINOR TWEAKS TO SKY COVER. 41 PREVIOUS... SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... CURRENT SATELLITE LOOP SHOWS BKN TO OVC ACROSS THE AREA WITH THE CLOUDS ROTATING AROUND THE HIGH PRESSURE RIDGE. THE SURFACE AND UPPER LEVEL RIDGES ARE ALMOST VERTICALLY STACKED WHICH IS DOING A VERY GOOD JOB OF KEEPING ANY CU DEVELOPMENT FROM BECOMING A SHOWER/THUNDERSTORM. EVEN WITH THE GOOD MOIST EASTERLY FLOW THIS RIDGE SHOULD KEEP UP PRECIPITATION FREE THROUGH THE SHORT TERM. A FEW OF OUR LOCAL MODELS...THE HRRR AND THE LOCAL WRF...ARE TRYING TO SHOW SOME SHOWERS DEVELOPING THIS AFTERNOON ACROSS OUR SOUTHEASTERN COUNTIES. BOTH OF THESE MODELS APPEAR TO BE PICKING UP ON WHAT LOOKS TO BE A SEA BREEZE FRONT AND BRINGS IN SO LIGHT SHOWERS THIS AFTERNOON. THE RIDGE IS FIRMLY ENTRENCHED ACROSS SE GA SO I WOULD TEND TO RULE OUT ANY PRECIP TODAY OR THURSDAY. FOR NOW AM KEEPING ANY PRECIP WORDING OUT WITH POPS REMAINING BELOW 15 PERCENT. WITH THE MOIST EASTERLY FLOW WE WILL SEE INCREASED CLOUD COVER AGAIN THURSDAY WITH SOME LOW STRATUS MOVING IN TONIGHT. THESE LOW CLOUDS WILL KEEP TEMPS UP A LITTLE HIGHER THAN THE PAST COUPLE OF NIGHTS WITH MAX TEMPS THROUGH THURSDAY STAY IN THE 80S AND 90S. 01 LONG TERM /FRIDAY THROUGH WEDNESDAY/... MAINLY ONLY TWEAKS TO THE LONG TERM. CAN NOT COMPLETELY RULE OUT SMALL CHANCES FOR SHOWERS/STORMS FRIDAY AFTERNOON OVER THE WESTERN CWA AND SATURDAY AFTERNOON FOR MUCH OF N AND CENTRAL GA. SHOWERS AND STORMS STILL MOST LIKELY SUNDAY AND MONDAY. BDL PREVIOUS DISCUSSION... ECMWF AND GFS IN GOOD AGREEMENT INTO THE WEEKEND WITH DIFFERENCES DEVELOPING AT THE EARLY PART OF NEXT WEEK. THE H5 RIDGE MAINTAINS ITS HOLD OVER THE CWA THROUGH FRIDAY...THEN THE RIDGE BEGINS TO BREAK DOWN AS THE UPPER TROUGH MOVES INTO THE MIDWEST. THIS WILL DRIVE A COLD FRONT INTO THE TENNESSEE AND OHIO VALLEYS LATE SATURDAY AND INTO SUNDAY AND MONDAY. THE ECMWF IS A LITTLE FASTER AND BRINGS MOISTURE WITH THE FRONT INTO THE CWA LATE SATURDAY NIGHT. BOTH MODELS PROG THE FRONT TO TAP INTO GULF MOISTURE SUNDAY BRINGING A GOOD CHANCE OF PRECIP TO MUCH OF THE CWA. DIFFERENCES DEVELOP SUNDAY NIGHT/MONDAY ON THE SPEED OF EXITING THE FRONT AND ASSOCIATED MOISTURE. THE ECMWF PUSHES THE FRONT THROUGH BUT THE SOUTHEAST CORNER OF THE CWA BY 12Z MONDAY WHILE THE GFS HOLDS THE FRONT BACK CLEARING ONLY THE NORTHWEST PART OF THE CWA BY 12Z MON AND THEN DEVELOPS A SECONDARY UPPER WAVE THAT INCREASES MOISTURE OVER MOST OF THE CWA DURING THE DAY MONDAY. AT THIS POINT WILL MAINTAIN HIGH POPS SUNDAY AND MONDAY AND BRING LOW OR NO POPS ON TUESDAY. 17 && .AVIATION... 06Z UPDATE... VFR TO START THE PERIOD...BUT EXPECT LOW MVFR TO POTENTIALLY IFR CIGS TO MOVE IN OVER THE NEXT FEW HOURS. EXPECT IMPROVEMENT STARTING BETWEEN 15-17Z...WITH VFR CONDITIONS EXPECTED THROUGH THE AFTERNOON. EXPECT ANOTHER ROUND OF LOW MVFR TO IFR CONDITIONS FRIDAY MORNING...AND WITH GUIDANCE MORE PESSIMISTIC FOR TOMORROW THAN TODAY...HAVE INTRODUCED IFR CIGS FOR ATL AROUND 10Z FRIDAY. SE WINDS THROUGH THE PERIOD GENERALLY BETWEEN 5-10KT THIS AFTERNOON...MAY SEE SOME LOW-END GUSTS AS WELL. //ATL CONFIDENCE...06Z UPDATE... MEDIUM ON TIMING OF CIGS TODAY AND TOMORROW. MEDIUM ON CIG HEIGHTS. HIGH ON ALL OTHER ELEMENTS. TDP && .PRELIMINARY POINT TEMPS/POPS... ATHENS 87 66 85 66 / 5 5 10 10 ATLANTA 85 66 85 67 / 5 5 20 10 BLAIRSVILLE 83 63 82 63 / 5 5 10 10 CARTERSVILLE 86 66 85 66 / 5 10 20 10 COLUMBUS 88 68 89 71 / 10 10 30 10 GAINESVILLE 83 66 83 65 / 5 5 10 10 MACON 88 66 88 65 / 5 5 10 10 ROME 87 66 85 66 / 5 20 30 10 PEACHTREE CITY 86 66 85 65 / 5 5 20 10 VIDALIA 90 67 90 70 / 5 5 5 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 AM EDT THU MAY 30 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 354 PM EDT WED MAY 29 2013 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RDG AXIS MOVING INTO THE UPR GRT LKS DOWNSTREAM OF DEEPENING UPR TROF OVER THE ROCKIES. ALTHOUGH SOME LO CLDS LINGER WITH LLVL MSTR SHOWN ON LOCAL 12Z RAOBS...COMBINATION OF SUBSIDENCE/LLVL ACYC FLOW ASSOCIATED WITH RDG AXIS AND ARRIVAL OF VERY DRY AIR ABV THE SHALLOW MSTR AS SHOWN ON THE 12Z MPX RAOB IS BRINGING DRY WX TO UPR MI. AT MID AFTN...THE LO CLDS ARE FINALLY MIXING OUT FAIRLY STEADILY. FARTHER TO THE SW...A PAIR OF SHRTWVS LIFTING NEWD OUT OF THE ROCKIES TROF ARE BRINGING SOME SHRA/TS TO COME AREAS IN THE PLAINS...ESPECIALLY OVER IOWA INTO SE MN AHEAD OF SFC-85 WARM FNT. MAIN FCST CONCERNS TNGT INTO THU WL BE SHRA/TS CHCS ASSOCIATED WITH RETURNING H85 WARM FNT AND SHRTWVS LIFTING NEWD OUT OF THE ROCKIES TROF. TNGT...MODELS ARE IN VERY GOOD AGREEMENT SHOWING CORE OF MID LVL DRY AIR OVER THE CWA EARLY THIS EVNG UNDER UPR RDG AXIS SHIFTING TO THE NE WITH APRCH OF WARM FNT TO THE SW. ALTHOUGH THE EARLY EVNG WL LIKELY BE DRY...EXPECT INCRSG SHRA/TS CHCS BY 03Z WITH APRCH OF SHRTWV NOW CAUSING SHRA/TS IN IOWA AS WELL AS AXIS OF HIER H85 DEWPTS AT NOSE OF STRENGTHENING H85 LLJ PUSHING KINX AT IWD TO 36 BY 06Z PER GFS FCST SDNGS. SINCE THE SHRTWV/MOISTENING ARE FCST TO IMPACT MAINLY THE W HALF OF THE CWA...EXPECT THE HIER POPS IN THAT AREA. IN FACT...THE ERN ZNS MAY REMAIN COMPLETELY DRY WITH KINX FCST NO HIER THAN ABOUT 25 AT ERY THRU 12Z THU. FCST SDNGS INDICATE STABILITY WL BE TOO MARGINAL FOR SVR STORMS...WITH SSI NO LOWER THAN ABOUT -1C AND MUCAPE NO HIER THAN 300-350 J/KG WITH NARROW SKINNY CAPE. EXPECT THE LOWEST MIN TEMPS OVER THE E CLOSER TO DEPARTING DRY AIRMASS. AREAS OF FOG ARE LIKELY TO FORM IN THIS AREA UNDER THE MORE PERSISTENT MID LVL DRY AIR. THU...AS WARM FNT SHIFTS TO THE N ON THU...EXPECT BULK OF LINGERING MRNG SHRA/TS OVER MAINLY THE W TO DIMINISH/END. QUESTION THEN BECOMES WHETHER ADDITIONAL CONVECTION WL FIRE IN THE WARM SECTOR AFT MRNG LO CLDS DSPT WITH DAYTIME HEATING/MIXING. THE BEST CHC FOR AFTN SHRA/TS WL BE PROBABLY BE OVER THE W...UNDER LOWER HGTS CLOSER TO CLOSED LO FCST TO DRIFT NWD THRU THE PLAINS. BUT EVEN THERE...GFS FCST SDNGS HINT AT SUBSIDENCE INVRN IN THE H75-8 LYR THAT MIGHT INHIBIT CONVECTION FOR AWHILE. IN FACT...BULK OF NUMERICAL GUIDANCE SHOWS NO SHRA/TS DVLPG UNTIL 21Z...WHEN SFC TEMPS ARE LIKELY TO RISE WELL INTO THE 80S UNDER H85 TEMPS IN THE 16-17C RANGE. MODIFIED GFS FCST SDNG AT IWD FOR T/TD 85/60 YIELDS SBCAPE NEAR 1250 J/KG. UNIDIRECTIONAL SSW FLOW AND SFC-6KM BULK SHEAR IN THE 20-30KT RANGE AS WELL AS HI FRZG LVL/WBLB ZERO OF 13.7K FT/12.6K FT WOULD INDICATE SVR THREAT IS FAIRLY SMALL. SINCE WARM FNT WL PROBABLY STALL OVER NW LK SUP...PAINTED THE HIER POPS OVER THE KEWEENAW CLOSER TO THIS BNDRY. SFC-6KM SHEAR IS FCST A BIT HIER IN THIS AREA AND UP TO 40 KTS...BUT LO CLDS SHOULD BE MORE PERSISTENT/STABILITY LOWER OVER THE KEWEENAW. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 354 PM EDT WED MAY 29 2013 WARMER THAN NORMAL TEMPERATURES AND ACTIVE WEATHER EXPECTED THROUGH THE END OF THE WORK WEEK AHEAD OF A LOW PRESSURE SYSTEM SHIFTING EASTWARD FROM THE PLAINS. A COOLING TREND IS EXPECTED OVER THE WEEKEND WITH NEAR NORMAL TEMPERATURES EXPECTED EARLY NEXT WEEK...HOWEVER OVERNIGHT LOWS ARE EXPECTED TO BE QUITE COOL EARLY NEXT WEEK WITH INLAND AREAS LIKELY REACHING THE LOW TO MID 30S. THURSDAY NIGHT THROUGH SATURDAY...UPPER LEVEL 500MB CLOSED LOW AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM CENTERED OVER THE DAKOTAS THURSDAY NIGHT WILL DRIFT SLOWLY EASTWARD INTO WESTERN MN BY THURSDAY NIGHT. THIS WILL KEEP UPPER MI IN WARM MOIST SOUTHERLY FLOW. THE BETTER MOISTURE TRANSPORT INTO THE REGION IS PROGGED TO OCCUR THURSDAY NIGHT THROUGH EARLY FRIDAY MORNING...AS PRESSURE GRADIENT IS INCREASED BETWEEN THE TROUGH TO THE WEST AND RIDGE TO THE EAST. UPPER MI IS ON THE NORTHERN FRINGES OF THIS PRESSURE GRADIENT...DIFFLUENT REGION...ALLOWING WIND SPEEDS TO DECREASE OVER UPPER MI. AS A RESULT...850MB CONVERGENCE IS ENHANCED OVER NORTHERN WI AND UPPER MI PROVIDING ENOUGH FORCING TO INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE REGION. MUCAPE VALUES ARE PROGGED TO BE AROUND 500-600 J/KG WHICH MAY BE ENHANCED A BIT AS 500MB SHORTWAVE ROTATES THROUGH THE REGION THURSDAY NIGHT. THE SURFACE LOW AND UPPER LEVEL LOW WILL THEN SHIFT FROM WESTERN MN FRIDAY MORNING INTO WI AND UPPER MI BY SATURDAY AFTERNOON. DURING THIS TIME PERIOD THE BETTER CHANCES FOR PRECIPITATION WILL SHIFT EASTWARD...REMAINING OVER MAINLY EASTERN UPPER MI AND MOST OF LOWER MI AS THE PRESSURE GRADIENT AND AFOREMENTIONED CONVERGENCE ALSO SHIFTS EASTWARD. ENOUGH MOISTURE WILL REMAIN IN PLACE OVER MUCH OF UPPER MI ALONG WITH COOLER AIR MOVING IN THROUGH THE DAY SATURDAY...TO KEEP THE CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. SATURDAY NIGHT THROUGH SUNDAY...THE LOW PRESSURE SYSTEM OVER UPPER MI SATURDAY NIGHT IS EXPECTED TO CONTINUE TO TREK EASTWARD SHIFTING TO SOUTHERN ONTARIO AND SOUTHERN QUEBEC THROUGH SUNDAY AFTERNOON. AS THIS HAPPENS...UPPER MI WILL BE PLACED ON THE BACK SIDE OF THE LOW PRESSURE SYSTEM ALLOWING COOLER AIR TO PUSH INTO THE AREA. ENOUGH WRAP AROUND MOISTURE WILL LINGER THROUGH SUNDAY AFTERNOON AND EVENING TO KEEP INCREASED CLOUD COVER OVER THE REGION ALONG WITH THE CHANCE OF SHOWERS. WHEN PLOTTING 1000-500MB OMEGA ON PLAN VIEW AND CROSS SECTIONS...INCREASED RH VALUES AND FORCING ARE COLLOCATED OVER MUCH OF THE UPPER PENINSULA THROUGH SUNDAY AFTERNOON. AS WAS THE CASE OVER THE LAST FEW SHIFTS...THE GFS TRIES TO PULL DRY AIR INTO THE REGION MUCH FASTER THAN THE EC/GEM...THEREFORE...WILL KEEP INCREASED CLOUD COVER IN THE FORECAST INTO THE LATE AFTERNOON INTO EARLY SUNDAY EVENING. THE GFS WOULD HAVE ALL CLOUD COVER OUT OF THE AREA BETWEEN 12 AND 18Z SUNDAY. SUNDAY NIGHT THROUGH WEDNESDAY...IN THE WAKE OF THE UPPER LEVEL 500MB LOW AND SURFACE LOW...EXPECT AN UPPER LEVEL 500MB RIDGE AND SURFACE HIGH TO BUILD EASTWARD FROM THE PLAINS SUNDAY NIGHT REACHING THE UPPER GREAT LAKES REGION BY LATE MONDAY MORNING. THE RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY EVENING...KEEPING CONDITIONS DRY AND SKIES MOSTLY SUNNY. SUNDAY NIGHT INTO MONDAY NIGHT...OVERNIGHT LOWS AREA EXPECTED TO BE FAIRLY COLD FOR THIS TIME OF YEAR AS 850MB TEMPS AREA EXPECTED TO DROP TO AROUND 0C TO 2C. THIS COUPLED WITH CALM WINDS...CLEAR SKIES AND DRY AIR...WILL ALLOW FOR MAXIMUM RADIATIONAL COOLING. AREAS INLAND WEST COULD FALL TO NEAR FREEZING SUNDAY NIGHT WHILE THE INLAND EAST AREAS COULD SEE NEAR FREEZING TEMPERATURES MONDAY NIGHT AS THE HIGH PRESSURE CENTER SHIFTS EASTWARD. THE NEXT AREA OF LOW PRESSURE DEVELOPING OVER SOUTHERN CANADA AND THE NORTHERN ROCKIES MONDAY AFTERNOON WILL SHIFT SLOWLY EASTWARD REACHING WESTERN UPPER MI BY LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. SIGNIFICANT TIMING AND SYSTEM INTENSITY DIFFERENCES EXIST FROM MODEL TO MODEL AND FROM MODEL RUN TO MODEL RUN CAUSING A BELOW AVERAGE CONFIDENCE LEVEL IN THE FORECAST FOR WEDNESDAY...THEREFORE HAVE DECIDED TO LEAN TOWARD A CONSENSUS OF THE MODELS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 129 AM EDT THU MAY 30 2013 A DISTURBANCE MOVING IN WL BRING THE THREAT OF SOME SHRA AND POSSIBLY A TS TO MAINLY IWD AND CMX OVERNIGHT. VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT IWD...BUT AT CMX WHEN THE SHOWERS MOVE THROUGH...COULD TEMPORARILY SEE MVFR CIGS/VIS OVERNIGHT. AT SAW...SIGNS ARE POINTING TO AN UPSLOPE FOG EVENT FROM LOW LEVEL MOISTURE COMING IN FROM LAKE MICHIGAN. EARLIER THINKING WAS SOME LOW CLOUDS WOULD FORM...BUT ESC DEW POINT HAS REALLY DROPPED AND THINK FOG WILL BE THE MAIN THREAT NOW. WILL GO MVFR VIS OVERNIGHT AT SAW WITH SOUTH UPSLOPE WINDS. MIXING AND HEATING WILL BRING BACK VFR BY MID MORNING AT SAW. COULD SEE SAME THING HAPPEN AT SAW MID THU EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 354 PM EDT WED MAY 29 2013 WITH GENERALLY WEAK PRES GRADIENT AND STABLE CONDITIONS OVER LAKE SUPERIOR...EXPECT WINDS TO BE UNDER 25KT THRU THE WEEK. WIDESPREAD FOG IS LIKELY...ESPECIALLY AFTER RAINFALL OCCURS OVER THE LAKE. AT LEAST PATCHY DENSE FOG IS LIKELY INTO SAT. HIGH PRESSURE WILL MOVE INTO THE AREA SUNDAY NIGHT AND REMAIN OVERHEAD THROUGH LATE TUESDAY NIGHT...KEEPING WINDS VARIABLE AND LESS THAN 25 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KEC AVIATION...07 MARINE...KEC
AREA FORECAST DISCUSSION
NWS GAYLORD MI
100 AM EDT THU MAY 30 2013 .SYNOPSIS... ISSUED AT 432 PM EDT WED MAY 29 2013 UNSETTLED WEATHER WILL BE THE RULE THROUGH THE NEAR FUTURE...AS A WARM FRONT GRADUALLY LIFTS NORTH INTO ONTARIO BY THURSDAY. THIS FEATURE WILL PROVIDE CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS THROUGH MID DAY ON THURSDAY. WE`LL GET A BREAK FROM THE ACTIVITY FOR THURSDAY AFTERNOON AND EVENING. BUT MORE CHANCES FOR SHOWERS AND STORMS WILL ENTER THE PICTURE FRIDAY THROUGH SUNDAY...AS A COLD FRONT SLOWLY SLIDES ACROSS THE GREAT LAKES. && .UPDATE... ISSUED AT 1259 AM EDT THU MAY 30 2013 03Z MESOANALYSIS SHOWS BROAD POOL OF THUNDERSTORM-COOLED AIR ACROSS MUCH OF WESTERN/CENTRAL WISCONSIN/NORTHEAST IOWA WITH THE LEADING EDGE OUTFLOW BOUNDARY ARCING ACROSS EASTERN WISCONSIN BACK INTO EAST CENTRAL IOWA. TEMPERATURES WERE IN THE 60S ACROSS A GOOD CHUNK OF NORTHERN LOWER...WITH DEW POINT TEMPERATURES NOT TOO DISSIMILAR. SKIES WERE MAINLY CLEAR ACROSS NORTHERN LOWER...WITH LOW CLOUDS ACROSS UPPER MICHIGAN AND JUST GRAZING THE NORTHEAST LOWER SHORELINE FROM LAKE HURON. GETTING SOME PATCHY FOG DEVELOPMENT AS WELL. LARGE AREA OF SHOWERS/THUNDERSTORMS ACROSS WISCONSIN SPREADING INTO WESTERN UPPER MICHIGAN...LEADING EDGE CONVECTION ALONG OUTFLOW BOUNDARY HAS BEEN WEAKENING AS IT APPROACHES THE WISCONSIN SHORELINE. 00Z APX SOUNDING SHOWED A FAIRLY SHALLOW MIXED LAYER CAPPED BY A SUBSIDENCE INVERSION IN THE 860-850MB LAYER. THERE IS A LOW LEVEL THETA-E RIDGE THAT RUNS FROM FKS-MBL SOUTHEAST TOWARD GRR-LAN-PTK WHERE THERE IS SOME POTENTIAL INSTABILITY THOUGH IT MAY BE TOO DRY/CAPPED TO SUPPORT CONVECTIVE DEVELOPMENT. WILL KEEP AN EYE ON THIS AREA TO MAKE SURE NO MISCHIEF DEVELOPS. OTHERWISE... WILL MAKE A FEW ADJUSTMENTS TO POP GRIDS AS WELL AS FOG TO COVER MARINE LAYER INTRUSION INTO FAR NORTHEAST LOWER. UPDATE ISSUED AT 1019 PM EDT WED MAY 29 2013 CLEAR CONCERNS FOR THE OVERNIGHT ARE FOG AND PRECIP. AIR MASS OVER MOST OF NORTHERN MI IS PRIMED FOR FOG. MARINE LAYER HAS COME CHARGING IN FROM LAKE HURON...WITH THE OSC AWOS/SPOTTERS/ FOG IMAGERY SHOWING FOG IN THAT AREA...ALMOST UP TO APN. PLENTY OF MARINE AIR STILL IN PLACE FROM THE STRAITS NORTH AS WELL. MEANWHILE...RADIATIONAL COOLING BARELY UNDERWAY...BUT IS ALREADY REDUCING VSBYS AT PLN AND BELLAIRE. WE HAD GROUND FOG DEVELOPING IN A FIELD ADJOINING THE OFFICE RIGHT AT SUNSET. OF COURSE... FAVORABLE RADIATIONAL COOLING CONDITIONS WILL BE COMING TO AN END SOON...AS A THICK CIRRUS SHROUD IS ADVANCING ABOVE LAKE MI AND CENTRAL UPPER MI. THIS SHOULD KEEP WIDESPREAD PEA SOUP FROM FORMING...BUT HAVE STEADILY EXPANDED FOG MENTION AND SEVERITY IN THE GRIDDED FORECASTS. HAVE ALSO REJIGGERED PRECIP CHANCES. RADAR TRENDS IN WI REMAIN SOMEWHAT OMINOUS AT 1ST GLANCE. BUT THE 00Z SOUNDING FROM GRB IS RELATIVELY DRY (PWAT 0.9) AND CAPPED...AND THAT AIR MASS ISN/T GETTING MORE UNSTABLE WITH TIME. 00Z APX SOUNDING WAS LESS UNSTABLE AND MORE CAPPED. THOUGH A WARMER/MORE MOIST AIR MASS WILL TRY TO WORK NORTHWARD INTO NORTHERN MI...THE LOW LEVEL JET WILL BE MUCH STRONGER TO OUR WEST. UPSTREAM MCS APPEARS TO BE EVOLVING IN RESPONSE...WITH LIGHTNING BECOMING LESS COMMON ALONG IT/S LEADING (EASTERN) EDGE...AND MORE COMMON ALONG THE RIGHT REAR (SOUTHWEST) FLANK. THUS...THE EARLIER FORECAST THINKING STILL APPEARS SOUND....LIFTING THE MCS REMNANTS NE-WARD ACROSS WI AND UPPER MI OVERNIGHT. LATEST HRRR RUNS REMAIN SUPPORTIVE OF THIS THINKING...WITH NO PRECIP IN THIS CWA EXCEPT IN FAR WESTERN CHIP/MACK. HAVE REMOVED CHANCE POPS FROM NE LOWER...ADDED SMALL CHANCE POPS ALONG THE NW LOWER MI COAST...AND RETAINED CHANCE POPS IN EASTERN UPPER (HIGHEST IN WESTERN CHIP/MACK). MIN TEMPS WILL BE QUITE MILD OUTSIDE OF MARINE-INFLUENCED AREAS. UPDATE ISSUED AT 739 PM EDT WED MAY 29 2013 APPEARS TO BE SAFE TO PULL PRECIP FROM THE SAGINAW BAY REGION THIS EVENING. CU FIELD IS IN DECLINE...AND EARLIER ECHOES ON RADAR HAVE EXITED. HAVE REDUCED CLOUD COVER SUBSTANTIALLY THIS EVENING...PER SAT TRENDS...ESPECIALLY IN NORTHERN LOWER MI. HAVE EXPANDED FOG INTO PARTS OF NORTHERN LOWER...ESPECIALLY WHERE LOW CLOUDS AND/OR MARINE AIR LINGERED LONGEST TODAY. TEMP/DEW POINT SPREADS ARE ALREADY 10F OR LESS AT APN/PLN...AND WITH WINDS LIGHTENING AND SKIES (TEMPORARILY) CLEARING...CERTAINLY LOOKS LIKE SOME FOG COULD FORM QUITE QUICKLY...PERHAPS EVEN BY MIDNIGHT. IT WILL BE AN INTERESTING RACE...AS A CIRRUS SHROUD FROM UPSTREAM SHRA/TSRA IS STEADILY ADVANCING ACROSS WI...AND WILL BE ENCROACHING ON THE AREA LATE EVENING AND ESPECIALLY OVERNIGHT. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 432 PM EDT WED MAY 29 2013 ON THE LATEST SURFACE WEATHER MAP...1022 MB HIGH PRESSURE WAS OVER VIRGINIA WHILE 1003 MB LOW PRESSURE WAS OVER NORTHERN ONTARIO AND 992 MB LOW PRESSURE WAS OVER WESTERN KANSAS...WHILE A SURFACE WARM FRONT WAS LOCATED JUST SOUTH OF THE FORECAST AREA. SATELLITE IMAGERY SHOWED LOTS OF CLOUDS ACROSS NORTHERN MICHIGAN BUT APX RADAR WAS VOID OF RETURNS. THE MAIN SHORT TERM FORECAST CONCERNS ARE NUMEROUS AND INCLUDE THUNDERSTORM POTENTIAL ACROSS SOUTHEAST ZONES INTO THE EVENING HOURS THEN THUNDERSTORM CHANCES OVERNIGHT AND AGAIN THURSDAY ACROSS ALL OF THE COUNTY WARNING AREA. THIS EVENING...CLOUDS HAVE BEEN A REAL CHALLENGE THIS AFTERNOON AS USUAL. MARINE STRATUS CONTINUES TO PLAGUE MARINE AREAS...AS WELL AS SPILLING INTO NORTHWEST LOWER WHILE SOUTHWEST ZONES HAVE SEEN AN INCREASE IN DIURNALLY DRIVEN CU (AFTER THE LOW CLOUDS MIXED OUT EARLIER). THE TREND HAS BEEN FOR CLOUDS TO GENERALLY DISSIPATE ACROSS THE SOUTHWESTERN ZONES AND THIS SHOULD CONTINUE THROUGH THE EVENING HOURS. COULD SEE A SHOWER OR THUNDERSTORM POP UP ACROSS SOUTHEAST ZONES OVER THE NEXT FEW HOURS WHERE THERE WAS THE MOST SUN/HEATING TODAY...IN COMBINATION WITH A BIT OF CONVERGENCE FROM A LAKE BREEZE OFF OF LAKE HURON. THEREFORE...WILL CONTINUE WITH LOW CHANCE POPS DOWN THERE. SEVERE POTENTIAL LOOKS LIMITED WITH WINDS ALOFT ON THE LIGHT SIDE. OVERNIGHT...CONVECTION ACROSS EASTERN MINNESOTA AND EASTERN IOWA EXPECTED TO TRACK TOWARD THE THETA-E RIDGE MOVING INTO THE NORTHERN HALF OF THE FORECAST AREA OVERNIGHT. STILL SOME DOUBT WHETHER THESE STORMS WILL SURVIVE THIS FAR EAST...SO WILL CONTINUE TO COVER IT WITH CHANCE WORDING. SEVERE POTENTIAL REMAINS LIMITED WITH 0-6KM BULK SHEAR OF 30 KNOTS OR LESS. WARM AND MUGGY OVERNIGHT WITH LOWS RANGING FROM THE MIDDLE 50S NORTH TO THE MIDDLE 60S SOUTH. THURSDAY...WE ARE EXPECTED TO FINALLY BREAK OUT INTO THE WARM SECTOR AS THE SURFACE WARM FRONT MOVES THROUGH THE REGION LEADING TO HIGHS RANGING FROM THE UPPER 70S NORTH TO THE MIDDLE 80S SOUTHEAST. IN ADDITION...THETA-E RIDGE BUILDS IN FROM THE WEST. LOOKING AT MODEL SOUNDINGS...NOT MUCH CAPPING IN EVIDENCE SO COULD SEE A FEW INSTABILITY DRIVEN THUNDERSTORMS DEVELOPING IN THE AFTERNOON AND EARLY EVENING HOURS...SO HAVE ADDED IN LOW CHANCE POPS. && .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 432 PM EDT WED MAY 29 2013 OVERVIEW: 4-WAVE HEMISPHERIC PATTERN IN PLACE TO START THIS FORECAST CYCLE WITH LONG WAVE TROUGHS ANCHORED OVER THE EASTERN PACIFIC (NEAR 150W) AS WELL AS FAR EASTERN CANADA (NEAR 60W)...WITH LOW AMPLITUDE RIDGING IN BETWEEN. ON THE SHORTER SCALE...FAST MID LEVEL FLOW IN PLACE ACROSS THE EASTERN PACIFIC DIGGING INTO AN INVERTED SHORT WAVE TROUGH IN THE WESTERN CONUS INTO THE PLAINS. ASSOCIATED SFC LOW CENTERED NEAR THE COLORADO/KANSAS BORDER THIS MORNING WITH A SOMEWHAT STATIONARY FRONT ARCHING UP INTO THE GREAT LAKES. SFC LOW AND STATIONARY FRONT CONTINUE TO DRIVE EPISODES OF SHOWERS AND STORMS FROM THE CENTRAL PLAINS THROUGH THE MIDWEST/LOWER GREAT LAKES. SHORT WAVE TROUGH WILL CONTINUE TO BE THE MAIN WEATHER PLAYER AS IT SLOWLY WORKS THROUGH THE PLAINS AND ULTIMATELY THE GREAT LAKES OVER THE NEXT SEVERAL DAYS. CONVECTIVE TRENDS/TIMING WILL BE THE TOUGH PART OF THE FORECAST AS THIS OCCURS. TEMPERATURES WILL INITIALLY BE ON THE WARMER SIDE OF THINGS (RAIN AND CLOUDS DEPENDENT) BUT TURN RATHER COOL AGAIN FOR THE WEEKEND AS THE TROUGH AND ASSOCIATED POCKET OF COLD AIR WORK THROUGH. SHAPING UP TO BE ANOTHER RIP-OFF SUMMER WEEKEND...SORRY. THURSDAY NIGHT AND FRIDAY...CLOSED AND NEARLY STACKED LOW PRESSURE SYSTEM EXPECTED TO BE MIGRATING SLOWLY ACROSS THE NRN PLAINS INTO THE UPPER MIDWEST THROUGH THIS TIMEFRAME WITH THE FRONT STRETCHED SOMEWHERE THROUGH THE NRN GREAT LAKES. MAIN FOCUS FOR CONVECTION THURSDAY NIGHT WILL LIKELY BE ACROSS THE MID TO UPPER MISSISSIPPI RIVER VALLEY WHERE WARM/MOIST SOUTHERLY INFLOW WILL INTERACT WITH BETTER SYNOPTIC FORCING. BUT THERE WILL BE THE CHANCE THAT SOME OF THAT ACTIVITY COULD EVENTUALLY SPREAD INTO THE GREAT LAKES THURSDAY NIGHT/FRIDAY MORNING AS MID LEVEL SHORT WAVE IMPULSE SWINGS UP INTO THE REGION. THAT SAID...TOUGH TO HAVE HIGH CONFIDENCE IN THE DETAILS AT THIS JUNCTURE GIVEN ALL THE CONVECTION THAT WILL OCCUR BETWEEN NOW AND THEN. SO FOR NOW WILL HAVE JUST CHANCY POPS OVERNIGHT THURSDAY NIGHT OVER THE WESTERN HALF OF THE CWA...AND ACROSS THE CWA ON FRIDAY. DETAILS WILL HAVE TO BE REFINED LATER. FRIDAY NIGHT THROUGH SUNDAY...PATTERN REMAINS UNSETTLED RIGHT ON THROUGH THE WEEKEND AS PESKY CLOSED LOW MAKES SLOW PROGRESS INTO THE GREAT LAKES. SHOWERS AND STORMS APPEAR MOST LIKELY ACROSS THE GREAT LAKES REGION FRIDAY NIGHT INTO SATURDAY AS THE ASSOCIATED SFC FRONT AND UPPER JET CORE PRESS INTO THE GREAT LAKES REGION...AND WILL HAVE HIGHEST POPS DURING THIS TIME. AFTER FROPA...SUNDAY SHAPING UP TO BE COOL AND DAMP ONCE AGAIN AS LIGHTER PRECIP LINGERS AND TEMPS DIP BACK BELOW NORMAL. MONDAY THROUGH WEDNESDAY...MID LEVEL TROUGH AND CORE OF COLD AIR SLOWLY RETREATS EASTWARD ON MONDAY FOLLOWED BY LOWER AMPLITUDE RIDGING FOR TUESDAY INTO WEDNESDAY. LARGE EXPANSE OF CANADIAN HIGH PRESSURE SETTLES IN FOR MONDAY AND TUESDAY WHICH WILL CLEAR THINGS OUT AND MAY LEAD MORE FROST POTENTIAL BOTH MONDAY AND TUESDAY MORNING. DAYTIME TEMPS REBOUND FOR TUESDAY AND WEDNESDAY BACK CLOSE TO NORMAL. HOWEVER...YET ANOTHER TROUGH IS SLATED TO BE DIPPING INTO THE UPPER MIDWEST/WESTERN GREAT LAKES AROUND MIDWEEK BRINGING ADDITIONAL RAIN CHANCES TO THE REGION TO ROUND OUT THE EXTENDED && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1258 AM EDT THU MAY 30 2013 FOG OVERNIGHT AT APN/PLN. SMALL CHANCES FOR SHRA/TSRA THURSDAY AFTERNOON/EARLY EVENING. A WEAK RIDGE OF HIGH PRESSURE HAS SHIFTED EAST TO THE EASTERN GREAT LAKES. THAT WILL ALLOW WARM/MOIST SOUTHERLY FLOW TO RETURN TO THE REGION THURSDAY. MARINE FOG/STRATUS HAS RETURNED TO APN WITH A LIGHT SE WIND OFF OF HURON...WHILE PLN HAS SEEN OLD FASHIONED RADIATIONAL FOG FORM. BOTH SITES ARE EXPECTED TO BE LIFR FOR THE BULK OF THE OVERNIGHT...THOUGH SOME SLIGHT IMPROVEMENT MAY OCCUR AS CIRRUS INCREASES OVERHEAD AND SLOWS THE COOLING PROCESS DOWN LOW. TVC/MBL WILL SEE MUCH LESS IN THE WAY OF FOG...THOUGH COULD DIP INTO MVFR TERRITORY AT TIMES. CONDITIONS WILL IMPROVE TO VFR AT ALL SITES THURSDAY MORNING. A CU FIELD WILL DEVELOP THURSDAY IN A WARM/MUGGY AIR MASS. SOME SHRA/TSRA WILL TRY TO GET GOING IN THE AFTERNOON. THE BEST CHANCE FOR THIS WILL BE INLAND FROM LAKE MI...AND WILL HAVE VCSH MENTIONED ONLY AT PLN/APN IN THE AFTERNOON. LIGHT WINDS OVERNIGHT. SOUTH WINDS THURSDAY...BREEZIEST AT MBL. && .MARINE... ISSUED AT 432 PM EDT WED MAY 29 2013 WINDS NOT EXPECTED TO BE MUCH OF AN ISSUE THROUGH TONIGHT...GENERAL SOUTHWEST GRADIENT WIND WITH SOME LAKE BREEZE INFLUENCE ON WHITEFISH BAY AND FAR NORTHERN LAKE HURON NEARSHORE ZONES. WINDS WILL BECOME MORE SOUTHERLY TONIGHT. REDUCED VISIBILITIES IN AREAS OF FOG AND HAZE WILL BE AN ISSUE THROUGH THURSDAY GIVEN RELATIVELY HUMID AIR MASS IN PLACE INTERACTING WITH COLDER LAKE WATERS. SOUTHERLY WINDS WILL INCREASE BY FRIDAY AFTERNOON...WITH SMALL CRAFT ADVISORIES LIKELY NEEDED ACROSS A MAJORITY OF THE NEARSHORE ZONES. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JPB SYNOPSIS...KAB SHORT TERM...AJS LONG TERM...TBA AVIATION...JZ MARINE...AJS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
353 AM CDT THU MAY 30 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 353 AM CDT THU MAY 30 2013 A VERY ACTIVE SHORT TERM IS IN STORE AS A POTENT UPPER WAVE WORKS ACROSS THE NATIONS MIDSECTION. H5 RAP ANALYSIS SHOWS A CLOSED LOW HAS DEVELOPED NEAR THE BLACK HILLS THIS MORNING...WITH A NEGATIVELY TITLED TROUGH EXTENDING FROM THERE DOWN TO NORTHEAST TEXAS. THE RADAR MOSAIC WEDNESDAY WAS CRAMMED FULL OF CONVECTION FROM HERE ALL THE WAY DOWN TO TEXAS...WHICH MEANS WITHIN THIS LARGE SCALE TROUGH THERE ARE NUMEROUS LEFT OVER WAVES/MCVS. ONE SUCH WAVE IS OVER SW IA THAT WILL SWING THROUGH HERE IN THE LATE MORNING. THE MAIN SYNOPTIC UPPER WAVE WILL BEGIN WORKING ACROSS MN THIS AFTERNOON AND EVENING. TO GO ALONG WITH ALL OF THE WAVES...A 50 KT LLJ IS CURRENTLY BLOWING ACROSS MN. THIS LLJ WILL SLOWLY DIMINISH THROUGH THE MORNING...BUT A MUCH STRONGER PUSH CURRENTLY OVER OK/KS WILL COME UP INTO SE MN/WRN WI THIS AFTERNOON/EVENING WITH THE PRIMARY SYNOPTIC WAVE. AT THE SFC...A 995 MB SFC LOW CAN BE FOUND NEAR PIERRE SOUTH DAKOTA...WITH A WARM FRONT SITTING ACROSS CENTRAL MN. DURING THE SHORT TERM...THIS LOW WILL BECOME OCCLUDED AND SLOWLY MEANDER NORTH INTO NODAK. THE WARM FRONT WILL CONTINUE TO MOVE NORTH TODAY...EVENTUALLY SETTLING ALONG THE INTERNATIONAL BORDER. BACK TO THE WEST...A COLD FRONT MOVING ACROSS SODAK TODAY WILL BE ENTERING WRN MN BY THE END OF THE PERIOD. FOR TODAY...EXPECT A BRIEF LULL IN ACTIVITY THIS MORNING AS WE WAIT FOR THE WAVE OVER SW IA TO GET HERE AROUND 15Z. FORECAST SOUNDINGS ACROSS THE ENTIRE CWA SHOW VERY LITTLE IF ANY CAPPING...SO EXPECT SHOWERS AND STORMS TO DEVELOP QUICKLY THIS MORNING ONCE A LITTLE DAYTIME HEATING KICKS IN. SINCE WE WILL NOT BE ABLE TO BUILD MUCH INSTABILITY THANKS TO DENSE CLOUD COVER AND THE FACT THAT ONCE A LITTLE DEVELOPS THE ATMO WILL QUICKLY CONSUME IT...THE SEVERE THREAT LOOKS FAIRLY LOW TODAY. FOR SEVERE WEATHER...WILL HAVE TO WATCH THAT SECOND LLJ WORKING UP IN THE AFTERNOON. BY 00Z THE RAP HAS 50 KT WINDS AT H85 UP INTO OUR WI CWA. LIKE YESTERDAY...THIS COULD LEAD TO THE THREAT FOR BOWING LINE SEGMENTS AND DAMAGING WINDS. AS FOR ANY HYDROLOGY ISSUES TODAY...THE ONLY AREA THAT WILL PROBABLY HAVE TO BE WATCHED IS THE EAU CLAIRE AREA. THEY SET A DAILY RAINFALL RECORD YESTERDAY AND WILL BE UNDER THE GUN FOR THE SECOND LLJ SURGE THIS AFTERNOON...WITH THE POTENTIAL FOR SOME TRAINING OF STORMS THIS AFTERNOON AND EVENING. TONIGHT...THE COLD FRONT WILL START ENTERING WRN MN WHILE THE LLJ WORKS INTO CENTRAL/ERN WI. THIS SHOULD MOVE THE HEAVY RAIN THREAT EAST OF THE MPX CWA TONIGHT. HOWEVER...HI-RES CAMS SHOW SCT RETURNS CONTINUING THROUGH THE NIGHT AHEAD OF THE FRONT...SO HAVE POPS SLOWLY RAMPING DOWN FROM LIKELIES TO START THE EVENING...DOWN TO 50% POPS OR LESS BY 12Z FRIDAY. FOR TEMPERATURES...GIVEN ALL OF THE CLOUD COVER...IT WILL NOT BE AN OVERLY WARM WARM SECTOR TODAY...WITH HIGHS LIKELY STAYING IN THE MID TO UPPER 70S...DESPITE H85 TEMPS BEING UP AROUND +15C. FOR TONIGHT...MIXED LAYER DEWPS ON THE NAM DROP INTO THE 40S BEHIND THE FRONT...SO LOWS IN THE WRN CWA COULD END UP BEING A FEW DEGREES COOLER THAN WHAT IS CURRENTLY INDICATED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 353 AM CDT THU MAY 30 2013 MODELS INDICATE RATHER STRONG TROUGH AXIS WORKING THROUGH THE AREA BY FRIDAY MORNING. THIS SHOULD WORK MUCH OF THE RAIN AND THUNDER TO THE NORTH AND EAST OF THE AREA LATE THURSDAY NIGHT. THIS SHOULD WORK A DRY SLOT NORTHEAST INTO SOUTHWEST PORITON OF THE CWA DURING FRIDAY MORNING. THE UPPER CIRCULATION THEN MOVES A FRONTAL BOUNDARY EAST ACROSS EASTERN HALF OF THE CWA FRIDAY AFTERNOON. THE DETERMINISTIC MODELS ARE INDICATING MODEST DESTABILIZATION ACROSS THE EASTERN HALF OF THE AREA...WITH ML MUCAPE INCREASING TO 1500/2000 J/KG. SHEAR INCREASES INTO THE AFTERNOON...ESPECIALLY INTO WESTERN WISCONSIN. THE ONLY INHIBITING FACTOR FOR CONVECTIVE INITIATION ALONG THE FRONT APPEARS TO BE RATHER WEAK SURFACE CONVERGENCE..WITH WINDS S-SW ALONG THE BOUNDARY. THE HIRES MODELS ARE SHOWING RATHER ROBUST CONVECTION DEVELOPING ALONG THE BOUNDAY AS IT MOVES INTO EASTERN MINNESOTA FRIDAY AFTERNOON. WILL HAVE TO MONITOR THIS SITUATION INTO FRIDAY...AS SEVERE WEATHER THREAT IS FORECAST TO BE LOW AT THIS TIME. FRONT EXITS TO THE EAST FRIDAY NIGHT TAKING THE HEAVY CONVECTIVE POTENTIAL WITH IT. THIS WILL LEAVE THE UPPER LOW OVER THE AREA THROUGH AT LEAST SATURDAY. SHOWERS LOOK TO BE A FAIR BET ESPECIALLY LATER IN THE DAY AS THE LOW MOVES EAST. WITH ABUNDANT CLOUD COVER...WILL BE LITTLE IN THE WAY OF HEATING...SO CONVECTIVE POTENTIAL IS LOW. CLEARING SHOULD MOVE INTO THE AREA LATER SATURDAY NIGHT...AND SUNDAY LOOKS LIKE THE BEST DAY OF THE WEEKEND...WITH SUNSHINE AND MILD TEMPERATURES. THE EXTENDED PORTION OF THE FORECAST STARTS OFF RATHER COOL...ESPECIALLY OVER THE EASTERN CWA MONDAY MORNING. THERE MAY EVEN BE A FROST POTENTIAL OVER A PORTION OF WEST CENTRAL WISCONSIN. THE NEXT WEATHER SYSTEM MOVES INTO THE AREA LATER MONDAY WITH SOME SHOWERS INTO THE WESTERN CWA. THE 00Z GFS AND ECMWF DIVERGE SOMEWHAT ON THE OVERALL EVOLUTION AND MOVEMENT OF THE NEXT LOW PRESSURE SYSTEM THAT MOVES ACROSS THE NORTHERN STATES THROUGH MUCH OF NEXT WEEK. IT DOES APPEAR THE THREAT OF MORE SHOWERS AND THUNDERSTORMS RETURNS BY MIDWEEK...WITH TEMPERATURES REMAINING BELOW NORMAL THROUGH THE PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1254 AM CDT THU MAY 30 2013 WITH THE NOSE OF A 40 KT LLJ SLOWLY WORKING ACROSS THE MPX AREA THIS PERIOD...FULLY EXPECT SEVERAL ROUNDS OF SHRA/TSRA THE REST OF TONIGHT THROUGH THU NIGHT. CONFIDENCE IS HIGH IN CONVECTIVE OCCURRENCE...BUT LIMITED ON EXACT TIMING AND PLACEMENT BEYOND THE FIRST 6 HOURS OF THE TAF...SO STUCK WITH LOTS OF VC GROUPS FOR NOW. STORM INTENSITY HAS BEEN SLOWLY DIMINISHING THE LAST COUPLE OF HOURS...AND EXPECT THIS TO CONTINUE THE REST OF THE EVENING. EXPECT A BRIEF LULL IN ACTIVITY LATE TONIGHT INTO THU MORNING...BEFORE SHRA/TSRA ACTIVITY QUICKLY FIRES UP AGAIN AFTER 15Z. SOUNDINGS THROUGH THURSDAY SHOW VERY LITTLE INHIBITION...SO SHOULD NOT TAKE MUCH TO GET STORMS GOING THIS WHOLE PERIOD. FOR CIGS...EXPECT THEM TO REMAIN MAINLY VFR OUTSIDE OF SHRA/TSRA ACTIVITY...THOUGH GIVEN DEGREE OF LOW LEVEL MOISTURE IN PLACE...WE COULD SEE SOME POCKETS OF MVFR CIGS DEVELOP THIS MORNING BEFORE QUICKLY LIFTING. KMSP...STORMS STARTING TO DIMINISH IN INTENSITY THIS EVENING AND EXPECT A LULL IN ACTIVITY BETWEEN ABOUT 10Z AND 15Z AS THE ATMO RECHARGES. EXPECT A QUICK RETURN TO SHRA/TSRA ACTIVITY IN THE MORNING...AS EVIDENCED BY THE HRRR...WHICH HAS STORMS DEVELOPING OVER MN BY 16Z. WINDS WILL REMAIN STRONG THROUGH THE PERIOD...BUT WILL BE FAIRLY PERSISTENT BETWEEN 140 AND 170 DEGS OUTSIDE OF ANY STORMS. ONLY TIME PERSISTENT MVFR CIGS ARE EXPECTED THIS PERIOD IS DURING PERIODS OF SHRA/TSRA. /OUTLOOK FOR KMSP/ FRI...SCT MVFR CIGS. SHRA/TSRA LIKELY. WINDS SW 10-15 KTS. SAT...MVFR CIGS POSSIBLE. SHRA LIKELY. WINDS WNW 5-10 KTS. SUN...MVFR CIGS POSSIBLE EARLY. WINDS N 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...DWE AVIATION...MPG
AREA FORECAST DISCUSSION
NWS GLASGOW MT
258 AM MDT THU MAY 30 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY... RAIN...HEAVY IN SOME AREAS... CONTINUE TO FALL OVER THE SW HALF OF THE FORECAST AREA EARLY THIS MORNING. RAINFALL TOTALS HAVE EXCEEDED 2 INCHES AT JORDAN AIRPORT IN CENTRAL GARFIELD COUNTY AND AT BIG SHEEP MOUNTAIN RAWS IN WESTERN PRAIRIE COUNTY SINCE WEDNESDAY AFTERNOON. THIS RAIN IS FOCUSED ALONG AN INVERTED SURFACE TROUGH THAT IS NEAR WINNETT... FORSYTHE AND BROADUS OR JUST SOUTH OF THE HEAVY PRECIP BAND. AN UPPER LOW OVER NE WYOMING IS STACKED WITH THE SURFACE LOW OVER NEBRASKA AT 09Z. THE SURFACE LOW WILL MOVE NORTH TODAY TAKING THE RAIN NORTH WITH IT. THIS WILL SPREAD THE RAIN NORTH INTO THE NE HALF OF THE FORECAST AREA THAT HAS STAYED DRY OVERNIGHT. BY THIS EVENING...THE SURFACE LOW WILL BE IN NORTH DAKOTA WHILE THE UPPER LOW WILL BE IN SOUTH DAKOTA. EASTERN MONTANA WILL BE IN THE WRAP AROUND MOISTURE IN THIS SYSTEM AND WITH THE AID OF A TROWAL (TROUGH OF WARM AIR ALOFT)... MODERATE TO HEAVY RAIN WILL CONTINUE OVER THE AREA INTO FRIDAY. AN ADDITIONAL 2+ INCHES OF RAIN CAN BE EXPECTED WITH THIS SYSTEM. WILL MAINTAIN FLOOD WATCH FOR THE ENTIRE FORECAST AREA THROUGH FRIDAY. THE SYSTEM WILL BEGIN TO MOVE TO THE EAST FRIDAY NIGHT WHICH WILL TAKE THE MOISTURE WITH. DRIER AIR WILL MOVE IN FROM THE NORTH ENDING THE RAIN. A SHORTWAVE RIDGE AND SURFACE HIGH PRESSURE WILL BRING DRY WEATHER ON SATURDAY. FORRESTER .LONG TERM...SATURDAY NIGHT THROUGH THURSDAY... SYNOPTIC SET UP... A LARGE TROUGH EXTENDS FROM THE HUDSON BAY DOWN INTO THE CENTRAL US PLAINS WHILE A SECOND ONE RUNS FROM THE THE PACIFIC NORTHWEST ALONG THE BRITISH COLUMBIAN SHORE AND BACK TO THE GULF OF ALASKA. A WEAK TROUGH RIDGE IS WEDGED BETWEEN THESE TWO LARGE FEATURES FROM UTAH THROUGH CENTRAL MONTANA AND UP INTO THE NORTHWEST TERRITORIES. SATURDAY NIGHT... UPPER SHORTWAVE RIDGE PUSHES INTO NORTHEAST MONTANA IN THE WAKE OF THE LARGE STORM SYSTEM WHICH WILL LEAD TO MUCH DRIER CONDITIONS. POPS WERE TRENDED DOWN TO NON MENTION THROUGH SATURDAY NIGHT AS ENSEMBLE MODELS ARE PLACING NO QPF ACROSS THE AREA AND DRY AIR FROM CANADA IS ANTICIPATED TO ENTER. SUNDAY INTO TUESDAY... MODELS CONTINUE TO HINT AT THE POTENTIAL FOR CONVECTION INITIATION AS A SHORTWAVE TROUGH BREAKS DOWN THE RIDGE ALOFT AND INTERACTS WITH A DEVELOPING THETA-E RIDGE. MODELS DIFFER ON TIMING AND PLACEMENT OF THIS WAVE AS WELL AS INTENSITY. THE LATEST EC AND GFS HAVE INITIATION OVER GREAT FALL TERRITORY AND JUST OFF THE FRONT RANGE. THEN BECOMING A MORE NOCTURNAL EVENT FOR THE GGW CWA. IF THIS VERIFIED... SOME STORMS COULD BECOME STRONG WITH A GOOD LIGHTNING SHOW... BUT LOCALLY SEVERE WEATHER MIGHT BE HARDER TO COME BY THAN PREVIOUS RUNS PREDICTED. A SECOND ROUND OR STRONG THUNDER IS POSSIBLE MONDAY AFTERNOON AND EVENING... BUT SHOULD THE CENTER OF THE MID LEVEL LOW THAT WRAPS UP PASSING GGW BEFORE THE AFTERNOON CONDITIONS WILL QUICKLY BECOME LESS FAVORABLE. THUS...CONFIDENCE IS INCREASING ON MORE RAINFALL MONDAY AND MONDAY EVENING. BUT THE DETAILS SUCH AS TIMING AND PLACEMENT AND HOW STRONG THE STORMS WILL BE WILL STILL NEED TO BE WORKED OUT WITH LATER SHIFTS. MODELS STILL INDICATE A STRONG UPPER LEVEL JET STREAK OVER THE AREA SOMETIME LATE WEEKEND WHICH COULD MIX DOWN IN STORMS IF TIMING IS RIGHT. TUESDAY NIGHT AND BEYOND... MULTI MODEL ENSEMBLES BECOME INCREASINGLY IN DISAGREEMENT AT THIS POINT INDICATING LOWER CONFIDENCE. WHAT CAN BE INFERRED FROM THE TEA LEAVES IS A RIDGE BUILDING ACROSS THE HIGH PLAINS THROUGH WEDNESDAY NIGHT ALLOWING FOR A WARMING TREND THROUGH MID WEEK AND BUMPING UP DAYTIME HIGHS. AFTERWARD A TROUGH BEHIND THIS RIDGE IS EXPECTED TO ROLL INTO THE PACIFIC NORTHWEST AROUND THURSDAY. THIS WOULD SEND SHORTWAVES ZOOMING OVER THE HIGH PLAINS AND NORTHEAST MONTANA AND COULD GENERATE A BIT OF CONVECTION. GAH/MALIAWCO && .AVIATION... VFR TO MVFR VISIBILITIES UNDER RAIN SHOWERS. IFR CEILINGS POSSIBLE ELSEWHERE. ON AND OFF SHOWERS WILL CONTINUE THROUGH KGDV AND KGGW WHILE KOLF AND KSDY SHOULD REMAIN CLEAR OF RAIN THROUGH 09Z. HRRR GUIDANCE SUGGESTS A WINDOW OF CLEARING RAIN BETWEEN 09Z TO 12Z MOVING FROM EAST TO WEST WITH THE KGGW TERMINAL POSSIBLY BEING CLEAR OF RAIN THROUGH NEARLY 15Z. AFTERWARD... ANOTHER LARGE BAND OF RAIN WITH MVFR CONDITIONS IS PROGGED THROUGH THE END OF THE TAF CYCLE. WHILE SOME AREAS MAY CLEAR FROM RAIN...RAIN FREE AREAS MAY ACTUALLY BECOME WORSE WITH TEMPORARY IFR CONDIITONS DUE TO CEILINGS DROPPING IN WHAT WOULD RAPIDLY BECOME COLDER LOCATIONS. WINDS WILL BE EASTERLY BETWEEN 5 AND 15 KTS THROUGH TONIGHT... THEN BECOME NORTHEASTERLY AND INCREASING TO 10 TO 20 KTS AFTER SUN UP. GAH && .HYDROLOGY... WITH RAINFALL HAVING EXCEEDED 2 INCHES ACROSS PARTS OF GARFIELD AND WESTERN PRAIRIE COUNTIES BASED ON AUTOMATED GAGES AT JORDAN AIRPORT AND BIG SHEEP MOUNTAIN RAWS... HAVE ISSUED A FLOOD WARNING THAT IS IN EFFECT THROUGH 730 PM THIS EVENING. A FLOOD WATCH REMAINS IN EFFECT FOR NORTHEAST MONTANA THROUGH FRIDAY. THIS WILL LEAD TO RISES IN STREAMS AND CREEKS WITH MAINSTEM RIVERS ALSO SEEING RISES BY THE WEEKEND INTO NEXT WEEK. AN ADDITIONAL 2+ INCHES OF RAIN IS LIKELY BETWEEN TODAY AND FRIDAY BEFORE THE SYSTEM MOVES TO THE EAST. FORRESTER && .GLASGOW WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS...DAWSON... EASTERN ROOSEVELT...GARFIELD...MCCONE...NORTHERN PHILLIPS... NORTHERN VALLEY...PETROLEUM...PRAIRIE...RICHLAND...SHERIDAN... SOUTHWEST PHILLIPS...WESTERN ROOSEVELT...WIBAUX. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
325 AM MDT THU MAY 30 2013 .DISCUSSION... DRYLINE HAS SO FAR STAYED TO THE EAST OF NEW MEXICO THIS MORNING AND ALTHOUGH IT/S FAIRLY CLOSE TO HOBBS DON/T EXPECT IT TO GET MUCH FARTHER WEST IF AT ALL. IN THE NORTHEAST DEWPOINTS HAVE COME UP AS THE SFC LOW SHIFTED INTO THE TX/OK PANHANDLES BUT THIS INCREASE LIKELY WON/T LAST LONG WITH THE RUC FORECASTING A WEAK SFC LOW TO REDEVELOP OVER SE CO BY MIDDAY. MODELS ALSO SHOW CURRENT BATCH OF MID LEVEL MOISTURE EXITING BY MIDDAY. UPPER JET TO RETREAT NWD TODAY BUT WILL BE STRETCHED OVER FAR NRN NM AND COLORADO...COMBINED WITH THE SFC LOW PLACEMENT WILL HAVE LOW END WIND ADVY OVER SOME OF THE NORTH CENTRAL/NORTHEAST SOUTH TO CLINES CORNERS. DRY INTO FRIDAY NIGHT. ANOTHER WINDY DAY ON FRIDAY WITH CRITICAL FIRE WX CONDITIONS POSSIBLE. ANOTHER BATCH OF MID LEVEL MOISTURE PASSES OVERHEAD TONIGHT AND FRIDAY BUT ANYTHING MORE THAN A FEW SPRINKLES OUT OF IT...IF THAT...WOULD BE A SURPRISE. SURFACE FRONT PUSHES THROUGH FRIDAY NIGHT WITH THE BACK DOOR FRONT INTO THE EAST SATURDAY. LOW LEVEL MOISTURE APPEARS TO MOVE IN FROM THE SOUTH AND SOUTHEAST WITH INCREASING INSTAB SO WENT AHEAD AND SPREAD SOME SMALL POPS FROM THE EAST SLOPES OF THE SOUTH CENTRAL MOUNTAIN ACROSS CHAVES COUNTY AND NORTHEAST ALONG THE TX BORDER SATURDAY AFTERNOON ALTHOUGH FOR NOW BEST CONFIDENCE IS IN THE SOUTHEAST. ANOTHER BLOB OF MID LEVEL MOISTURE TO MIGRATE OVER THE SOUTHERN HALF OF THE STATE AND COULD NOT RULE OUT A FEW SPRINKLES UNDERNEATH IT...BUT LEFT MENTION OUT OF FCST FOR NOW. IN FACT THE ADJMET GUIDANCE DOES PAINT SOME LOW POPS OVER THE SOUTHWEST MTS. INCREASED POPS SOMEWHAT SUNDAY ESPECIALLY ALONG THE CENTRAL MT CHAIN. LEFT THE MENTION OF DRY CONVECTION FROM THE RGV WWD ALTHOUGH COULD BE A MIX WITH AT LEAST SOME MEAGER MEASURABLE PCPN DEPENDING IF THE SURGE IS AS STRONG AS DEPICTED SO FAR. HOWEVER...MONDAY STARTS TO DRY OUT AND TUESDAY EVEN MORE SO. REMOVED THE POPS IN THE EAST FOR TUESDAY NIGHT...AND PROBABLY SHOULD HAVE FOR TUESDAY AS WELL AS RIGHT NOW IT LOOKS DRY. ANOTHER BACKDOOR FRONT WEDNESDAY LOOKS TO PUSH INTO THE RGV WEDNESDAY NIGHT...SO POPS/WX GRIDS FOR MID TO LATE WEEK HAVE BEEN UPDATED. && .FIRE WEATHER... ...WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS DUE TO STRONG WIND AND LOW HUMIDITY FOR MUCH OF NORTHERN AND CENTRAL NEW MEXICO THROUGH FRIDAY... ...DRY LIGHTNING THREAT INCREASING SUNDAY CENTRAL/WEST... MOVING INTO DAY 2 OF A PROTRACTED CRITICAL FIRE WEATHER PATTERN THAT WILL EXTEND THROUGH FRIDAY. THEREAFTER...FAR LESS WIND BUT GROWING CONFIDENCE IN A SUBSTANTIAL WESTERLY PUSH OF LOWER LEVEL MOISTURE THAT WILL RESULT IN A SIGNIFICANT DRY LIGHTNING THREAT FOR CENTRAL/WESTERN AREAS BY SUNDAY. SATURDAY LOOKS TO BE A CLASSIC TRANSITION DAY AS RICHER LOW LEVEL MOISTURE INITIALLY MAKES A RETURN TO THE EC/SE PLAINS AS SURFACE WINDS VEER TO SELY AND TAPS INTO A NOW SEMI-PERMANENT POOL OF GULFMEX MOISTURE. POTENTIAL FOR SOME DRIER STORMS ALONG THE EAST SLOPES OF THE CENTRAL/SC MOUNTAIN SATURDAY PM. HIGHER DEW POINT AIR ALSO CREEPING NORTHWARD ALONG THE RGV AND THAT COUPLED WITH A SUBTLE AND ALWAYS SNEAKY UPTICK IN MID-LEVEL MOISTURE AS THE UPPER RIDGE EXPANDS/BUILDS NORTHWARD COULD RESULT IN AT LEAST AN ISOLATED DRY LIGHTNING THREAT OVER THE WC/SW HIGHER TERRAIN AS EARLY AS SATURDAY AFTERNOON OR EVENING. THIS WILL BE CLOSELY MONITORED. EVEN THE SLIGHTEST UPTICK IN LOWER/MID LEVEL MOISTURE IN THE PRESENCE OF VERY STEEP LAPSE RATES THAT ARE TYPICAL OF THE DEVELOPING PATTERN THIS WEEKEND SEEMS TO RESULT IN MORE THAN EXPECTED BUILDUPS/VIRGA AND DRY CG/S. WE SHALL SEE. SUNDAY AFTERNOON/EVENING LOOKING TO BE THE MORE CRITICAL DAY WITH RESPECT TO DRY LIGHTNING THOUGH MONDAY COULD BE FAIRLY ACTIVE EAST OF THE DIVIDE. IN THE MEANTIME...LARGE-SCALE UPPER TROUGH SLOWLY PIVOTING NORTHEAST FROM THE CENTRAL/NORTHERN ROCKIES EARLY THIS MORNING. BASE OF THE TROUGH TRANSLATED EASTWARD OVER OUR AREA THIS PAST NIGHT AND PRESENT INDICATIONS ARE THAT THE STRONGEST MID-LEVEL WINDS WILL PASS OVERHEAD BEFORE MIDDAY. THAT SAID...AN ANOMALOUSLY STRONG UPPER LEVEL JET ORIENTED NW TO SE FROM THE GREAT BASIN TO THE FOUR CORNERS REGION WILL NOT SHIFT NORTHWARD APPRECIABLY TODAY. AS A RESULT...WIND SPEEDS THOUGH A BIT LESS THAN YESTERDAY WILL STILL BE SIGNIFICANT WITH FREQUENT GUSTS OF 35-40 MPH ACROSS THE NORTH. SURFACE LOW NOT AS FAVORABLE EITHER. NO CHANGES TO THE FIRE WEATHER WATCH FOR FRIDAY THOUGH BELT OF STRONGEST WINDS DO SHIFT SOUTHWARD PER PREVIOUS FORECAST. VERY DEEP MIXING CONTINUES TODAY BEFORE MAX MIXING HEIGHTS TREND DOWNWARD SLIGHTLY ON FRIDAY. LOWEST RH VALUES CENTRAL VALLEY CORRIDOR AND IN THE EAST. EXTENDED MODELS STILL TRENDING DRIER/BREEZIER EARLY NEXT WORK WEEK FOLLOWING OUR LIGHTNING PERIOD. BACK TO VERY DEEP MIXING AND GUSTY AFTERNOON/EVENING PERIODS THOUGH TOO EARLY TO GAUGE STRENGTH OF ANY SUSTAINED WINDY PERIODS. KJ && .AVIATION... 06Z TAF CYCLE TROUGH ALOFT EXTENDING FROM NORTHERN ROCKIES SOUTHWARD ACROSS EASTERN NM TO THE TX BIG BEND COUNTRY...AS SURFACE TROUGH EXTENDS FROM CENTRAL NEBRASKA ACROSS THE TX PANHANDLE. CLOUD COVER AOA BKN/OVC100 MOVING EAST ACROSS THE STATE ALONG INTERSTATE 40 CORRIDOR WILL DISSIPATE BY 12Z THU MORNING. GUSTY WEST WINDS REDEVELOPING RAPIDLY FROM 14Z ONWARD ACROSS THE EAST SLOPES OF OF THE CENTRAL MTS...AND THEN STATEWIDE BY 18Z. AREAS OF BLOWING DUST WILL DROP VIZ TO 5SM OR LESS AT TIMES...ESPECIALLY OVER THE EASTERN PLAINS. SHY && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 81 49 82 42 / 0 0 0 0 DULCE........................... 73 41 75 32 / 0 0 0 0 CUBA............................ 77 43 77 40 / 0 0 0 0 GALLUP.......................... 81 45 82 37 / 0 0 0 0 EL MORRO........................ 79 44 81 40 / 0 0 0 0 GRANTS.......................... 82 47 84 39 / 0 0 0 0 QUEMADO......................... 81 47 83 43 / 0 0 0 0 GLENWOOD........................ 85 49 87 57 / 0 0 0 0 CHAMA........................... 71 37 70 30 / 5 0 5 5 LOS ALAMOS...................... 80 45 81 41 / 0 0 0 0 PECOS........................... 78 47 80 44 / 0 0 0 0 CERRO/QUESTA.................... 73 38 74 32 / 0 0 0 0 RED RIVER....................... 64 36 63 36 / 0 0 0 0 ANGEL FIRE...................... 69 38 71 34 / 0 0 0 0 TAOS............................ 75 40 77 34 / 0 0 0 0 MORA............................ 75 42 78 39 / 0 0 0 0 ESPANOLA........................ 83 45 84 45 / 0 0 0 0 SANTA FE........................ 80 45 80 43 / 0 0 0 0 SANTA FE AIRPORT................ 82 49 84 45 / 0 0 0 0 ALBUQUERQUE FOOTHILLS........... 83 56 85 50 / 0 0 0 0 ALBUQUERQUE HEIGHTS............. 85 60 88 56 / 0 0 0 0 ALBUQUERQUE VALLEY.............. 86 54 90 56 / 0 0 0 0 ALBUQUERQUE WEST MESA........... 86 58 88 54 / 0 0 0 0 LOS LUNAS....................... 88 60 91 56 / 0 0 0 0 RIO RANCHO...................... 85 58 87 54 / 0 0 0 0 SOCORRO......................... 90 62 94 59 / 0 0 0 0 SANDIA PARK/CEDAR CREST......... 82 51 83 49 / 0 0 0 0 TIJERAS......................... 83 55 85 48 / 0 0 0 0 MORIARTY/ESTANCIA............... 82 50 84 47 / 0 0 0 0 CLINES CORNERS.................. 81 51 80 47 / 0 0 0 0 GRAN QUIVIRA.................... 84 53 85 50 / 0 0 0 0 CARRIZOZO....................... 84 59 87 56 / 0 0 0 0 RUIDOSO......................... 76 57 80 57 / 0 0 0 0 CAPULIN......................... 80 48 82 40 / 0 0 0 5 RATON........................... 81 44 84 40 / 0 0 0 5 SPRINGER........................ 82 43 84 40 / 0 0 0 0 LAS VEGAS....................... 80 48 82 41 / 0 0 0 0 CLAYTON......................... 87 52 86 48 / 0 0 0 5 ROY............................. 84 51 85 46 / 0 0 0 5 CONCHAS......................... 90 53 91 52 / 0 0 0 0 SANTA ROSA...................... 91 54 92 52 / 0 0 0 0 TUCUMCARI....................... 95 55 95 53 / 0 0 0 5 CLOVIS.......................... 92 57 94 56 / 0 0 0 5 PORTALES........................ 94 57 95 56 / 0 0 0 5 FORT SUMNER..................... 94 59 96 55 / 0 0 0 0 ROSWELL......................... 96 64 99 62 / 0 0 0 0 PICACHO......................... 89 63 92 59 / 0 0 0 0 ELK............................. 84 62 88 58 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ101>104-106>108. FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR THE FOLLOWING ZONES...NMZ101>108. WIND ADVISORY FROM 10 AM THIS MORNING TO 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ510>516-523-527>529. && $$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1232 AM CDT THU MAY 30 2013 .UPDATE... ISSUED AT 1231 AM CDT THU MAY 30 2013 CURRENT FORECAST IS ON TRACK WITH HOURLY GRIDS CLOSELY MATCHING LATEST OBSERVATIONS. WATER VAPOR SHOWS NEGATIVELY TILTED TROUGH EXTENDING FROM CENTRAL MONTANA TO NEBRASKA/SOUTH DAKOTA CONTINUING TO PIVOT TOWARD NORTH DAKOTA. ASSOCIATED SURFACE LOW IS LOCATED OVER SOUTH DAKOTA. RELATIVELY MOIST DEWPOINTS IN THE LOW 60S ARE ADVECTING INTO SOUTHEAST NORTH DAKOTA WITH WARM FRONT GENERALLY IN THE VICINITY OF THE ND/SD BORDER. SHOWERS AND ISOLATED/SCATTERED THUNDERSTORMS HAVE EXPANDED THE PAST COUPLE HOURS ACROSS SOUTH CENTRAL AND SOUTHEAST ND WITH THIS AREA MOVING TO THE NORTHWEST...JUST ABOUT AT BISMARCK AT THIS TIME. MODELS ARE IN DECENT AGREEMENT WITH SOME SLIGHT DIFFERENCES IN SURFACE LOW LOCATION. UPPER TROUGH REFERENCED ABOVE WILL CUT OFF THURSDAY MORNING RESULTING IN SURFACE LOW MOVING TO NORTH DAKOTA ON THURSDAY AND REMAINING NEARLY STATIONARY THROUGH THURSDAY NIGHT. UPDATE ISSUED AT 938 PM CDT WED MAY 29 2013 ONCE AGAIN...GIVEN THE LATEST RADAR TRENDS...THE 18 AND INCOMING 00 UTC DETERMINISTIC GUIDANCE AND 01 UTC RAP/HRRR SIMULATED REFLECTIVITY FORECASTS...REDUCED POPS THROUGH 06 UTC FOR MUCH OF THE AREA UNTIL THE ARRIVAL OF GREATER UPPER LEVEL FORCING AS CONVECTION ACROSS SOUTH DAKOTA THROUGH NEBRASKA MAY ALSO BE DISRUPTING MOISTURE TRANSPORT INTO NORTH DAKOTA. DO NOT ANTICIPATE SEVERE WEATHER TONIGHT ACROSS WESTERN AND CENTRAL NORTH DAKOTA...WITH A POTENTIAL RETURN OF THE THREAT TOMORROW AFTERNOON AND EVENING DEPENDENT UPON HOW MUCH CLEARING/INSOLATION IS ACHIEVED IN THE WARM SECTOR OF THE SURFACE LOW ACROSS SOUTH CENTRAL NORTH DAKOTA. UPDATE ISSUED AT 720 PM CDT WED MAY 29 2013 THE BIGGEST CHANGE WITH THIS UPDATE WAS TO REDUCE POPS...ESPECIALLY ALONG AND NORTH OF US HIGHWAY 2...GIVEN THE LATEST RADAR TRENDS AND THE 21 UTC HRRR SIMULATED REFLECTIVITY WHICH HAS MAINTAINED CONTINUITY WITH PREVIOUS RUNS WHICH KEEP MUCH OF NORTHERN NORTH DAKOTA PRECIPITATION FREE THROUGH AT LEAST 06 UTC. GIVEN THE MARGINAL INSTABILITY AND SHEAR...THE SMALL WINDOW FOR SEVERE HAIL AND/OR WINDS ACROSS THE JAMES RIVER VALLEY APPEARS TO BE QUICKLY CLOSING AND WILL FOCUS ON HEAVY RAIN MONITORING OVER THE SATURATED AREAS OF SOUTHERN NORTH DAKOTA. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 405 PM CDT WED MAY 29 2013 MAIN PROBLEM IN THE SHORT TERM PERIOD WILL BE PRECIPITATION AMOUNTS...PLACEMENT AND TIMING. CURRENTLY...SURFACE LOW PRESSURE OVER THE CENTRAL PLAINS WITH A WARM FRONT EXTENDING INTO EASTERN SOUTH DAKOTA AND SOUTHERN MINNESOTA. STRONG NEGATIVELY TILTED UPPER LEVEL TROUGH FROM THE NORTHWEST U.S. INTO THE CENTRAL ROCKIES. CURRENT CONVECTION IN OUR AREA IS LINING UP WITH THE THE STRONG WARM ADVECTION OVER THE EASTERN DAKOTAS INTO MINNESOTA...AS WELL AS STRONG UPPER LEVEL DIVERGENCE OVER EASTERN MONTANA. TONIGHT...THE UPPER LEVEL WAVE WILL LIFT NORTHWARD INTO THE NORTHERN HIGH PLAINS WITH THE SURFACE LOW TRACKING NORTH THROUGH SOUTH DAKOTA. THIS WILL BRING INCREASING SHOWERS AND POSSIBLY SOME THUNDERSTORMS TO WESTERN AND CENTRAL NORTH DAKOTA. ALTHOUGH WE DO THINK MOST AREAS WILL RECEIVE PRECIPITATION...WE HAVE CONTINUED THE TREND OF DELAYING THE ONSET...AND CUTTING BACK A LITTLE ON THE AMOUNTS. AGAIN..WE ARE IN A BIT OF A LULL BETWEEN THE STRONG WARM ADVECTION TO OUR EAST...AND THE STRONG FORCING AND DIVERGENT FLOW ALOFT ASSOCIATED WITH THE UPPER LEVEL SYSTEM TO OUR WEST. THURSDAY...THE UPPER LEVEL LOW CONTINUES TO LIFT NORTH THROUGH EASTERN MONTANA...WHILE THE SURFACE LOW LIFTS NORTH TO NEAR BISMARCK...THEN NORTHWEST TOWARDS WILLISTON. THIS PLACEMENT WOULD BRING GREATEST PRECIPITATION AMOUNTS TO THE NORTHERN HALF OF THE CWA...WITH DRIER AIR WORKING FROM SOUTH TO NORTH THURSDAY AFTERNOON. THIS WOULD BRING AN END TO PRECIPITATION ACROSS THE SOUTH HALF OF THE CWA...BUT COULD ALSO ALLOW FOR A PERIOD OF DESTABILIZATION THURSDAY AFTERNOON IN THE DRIER AIR. WITH THE SURFACE AND UPPER LOWS JUST WEST...THIS WOULD INCREASE THE RISK OF THUNDERSTORMS IN A HIGH SHEAR ENVIRONMENT. DUE TO SOME MODEL AND TIMING UNCERTAINTIES WILL NOT MENTION SEVERE AT THIS TIME...AND LET LATER SHIFTS UPDATE AS NEEDED. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 405 PM CDT WED MAY 29 2013 WET AND COOL WEATHER REMAINS OVER THE NORTHERN PLAINS THROUGH EARLY SATURDAY...FOLLOWED BY QUIET CONDITIONS SATURDAY THROUGH SUNDAY AFTERNOON...THEN A RETURN TO ACTIVE CONDITIONS SUNDAY NIGHT THROUGH TUESDAY. THE LONG TERM BEGINS THURSDAY EVENING WITH A CLOSED UPPER LEVEL LOW CENTERED OVER SOUTHWEST ND/SOUTHEASTERN MONTANA...AND AN AREA OF SURFACE LOW PRESSURE OVER WESTERN NORTH DAKOTA. ACTIVE WEATHER WILL BE ONGOING AT THE START OF THE PERIOD WITH WIDESPREAD RAIN SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE NORTH AND FAR WEST WRAPPING AROUND THE UPPER LOW. OVER SOUTH CENTRAL AND SOUTHEASTERN NORTH DAKOTA...A DRY SLOT IS EXPECTED TO PROVIDE SOME CLEARING THURSDAY AFTERNOON INTO THURSDAY EVENING...WITH THE RESULTANT HEATING ACTING TO INCREASE SURFACE INSTABILITY WITH UPWARDS TO NEAR 1500 J/KG OF CAPE FORECAST NEAR A SFC COLD/OCCLUDED FRONT. MAY SEE ISOLATED SEVERE STORMS DEVELOP GIVEN THE ADVERTISED INSTABILITY PERSISTING INTO THE EVENING NEAR THE BOUNDARY. LOW LINGERS ACROSS THE NORTHERN PLAINS THROUGH FRIDAY BEFORE MORPHING INTO AN OPEN WAVE AND PUSHING OFF TO OUR EAST SATURDAY AFTERNOON. AS THIS OCCURS...WILL SEE WRAP AROUND PRECIPITATION SPREAD FROM WEST TO EAST FRIDAY MORNING THROUGH FRIDAY EVENING...THEN DECREASING CLOUDS AND CHANCES FOR RAIN FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT INTO SATURDAY. OVERALL EXPECT UPWARDS TO AN ADDITIONAL ONE HALF INCH OF RAINFALL THURSDAY NIGHT THROUGH SATURDAY MORNING ACROSS WEST AND CENTRAL ND. DRY WEATHER REMAINS IN THE FORECAST SATURDAY NIGHT THROUGH SUNDAY AFTERNOON WITH A SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE BUILDING EAST ACROSS THE NORTHERN PLAINS. ACTIVE WEATHER RESUMES SUNDAY NIGHT INTO EARLY NEXT WEEK AS ANOTHER UPPER LOW/TROUGH PUSHES ACROSS THE NORTHERN ROCKIES AND EVENTUALLY INTO THE NORTHERN PLAINS. WELL BELOW NORMAL TEMPERATURES FRIDAY AND SATURDAY WITH HIGHS 55-65 AND LOWS IN THE UPPER 30S TO MID 40S. WILL NEED TO MONITOR FOR POSSIBLE FROST SATURDAY NIGHT/SUNDAY MORNING WHEN WINDS ARE EXPECTED TO BE LIGHT...SKIES CLEAR...AND SFC DEWPOINT TEMPS FORECAST TO FALL AS LOW AS 35F DEGREES SOME AREAS. DAYTIME AND NIGHTTIME TEMPERATURES MODERATE TOWARDS NORMAL SUNDAY-TUESDAY WITH HIGHS GENERALLY IN THE 60S AND LOW 45-55. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY) ISSUED AT 1231 AM CDT THU MAY 30 2013 SHOWERS AND THUNDERSTORMS WILL CONTINUE TO INCREASE IN COVERAGE ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE NIGHT...WITH FLIGHT CONDITIONS TRENDING TOWARDS MVFR/IFR AT ALL SITES IN MODERATE RAIN AND LOW CEILINGS. DEPENDING ON HOW MUCH CLEARING THERE IS THURSDAY AFTERNOON...STRONG TO SEVERE THUNDERSTORMS MAY BE POSSIBLE FOR THE KDIK...KBIS AND KJMS TAF SITES THURSDAY AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 405 PM CDT WED MAY 29 2013 SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON AND TONIGHT...AND MOVE FROM SOUTH TO NORTH ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THURSDAY AFTERNOON. THE POTENTIAL FOR HEAVY RAIN EXISTS ACROSS THE WEST AND CENTRAL... ESPECIALLY LATE TONIGHT THROUGH THURSDAY. WIDESPREAD RAINFALL AMOUNTS OF THREE QUARTERS OF AN INCH...TO TWO INCHES ARE FORECAST THOUGH THIS PERIOD. HOWEVER...THE LATEST GUIDANCE CONTINUES TO SUGGEST A LESS LIKELY SCENARIO FOR AMOUNTS GREATER THAN 1.5 INCHES OVER MUCH OF THE CENTRAL. THE MOST LIKELY AREAS FOR THE HIGHEST AMOUNTS APPEAR TO BE IN THE FAR NORTH AND FAR WEST...WITH THE HIGHEST AMOUNTS IN EASTERN MONTANA AND SOUTHERN CANADA. STREAM AND RIVER RISES ARE POSSIBLE BY THE END OF THE WEEK INTO THIS COMING WEEKEND. AN ADDITIONAL ONE QUARTER TO ONE HALF INCH WILL BE POSSIBLE FRIDAY AND FRIDAY NIGHT. CHANCES FOR RAIN DECREASE SATURDAY INTO SATURDAY NIGHT. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JNS SHORT TERM...TWH LONG TERM...NH AVIATION...JNS HYDROLOGY...TWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
442 AM EDT THU MAY 30 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED PATTERN. && .NEAR TERM /THROUGH TONIGHT/... AS OF 440 AM EDT THURSDAY...MVFR CIGS ARE FILLING IN QUICKLY OVER NE GA AND WE APPEAR TO BE ON TRACK FOR A STRATUS DECK TO INVADE THE FORECAST AREA FROM THE SOUTHWEST OVER THE NEXT FEW HOURS. I DID TWEAK SKY COVER TO ACCOUNT FOR CURRENT TRENDS...HOWEVER. AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS RUNNING ABOUT A CATEGORY ABOVE NORMAL. WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN NC. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC. MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO GOING WITH A DRY FCST. ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL. OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA FOR SUNDAY INTO EARLY NEXT WEEK. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN. EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE NORMAL OVERNIGHT TEMPS. THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS WILL BE NEAR NORMAL. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... AT KCLT...MODEL GUIDANCE AND PERSISTANCE FROM LAST NIGHT IMPLIES THAT STRATUS WILL DEVELOP DOWN ACROSS THE MIDLANDS AND CLOSER TO THE MOUNTAINS TOWARD MORNING. IT/S A TOUGH CALL...BUT KCLT MAY NOT ACTUALLY SEE A CIG LATER TONIGHT. THEREFORE I/VE BACKED OFF THE BKN CIG AND GONE SCT010 STARTING AT 10 UTC. THE NAM BUFKIT SOUNDINGS APPEAR TO BE CAPPED AND NOT SUPPORTIVE OF A CU FIELD IN THE AFTN. I THINK THAT/S A HAIR OVERDONE AND I DO KEEP FEW040 AROUND DURING THE AFTN. WINDS WILL BE LIGHT OUT OF THE S TO SSW THROUGH THE DAY. ELSEWHERE...PER THE SREF PROBS OF CIGS LOWER THAN 3KFT AND THE AREA OF HIGHEST LLVL RH ON THE RUC AND PERSISTANCE WITH LAST NIGHT...WE SHOULD SEE STRATUS DEVELOP OVER NORTH CENTRAL GA STARTING IN AN HOUR OR TWO. IT SHOULD EXPAND NORTHEAST WITH TIME...AND SHOULD EVENTUALLY WORK ACROSS THE UPSTATE TAF SITES. EXACTLY WHEN THIS HAPPENS ISN/T AN EASY CALL. FOR NOW I HAVE MVFR CIGS DEVELOPING AT 10 UTC AT KAND AND NOT TIL 12 UTC AT KGSP. HOPEFULLY THAT WILL BE CLOSE. I/M LESS CONFIDENT OF STRATUS AT KAVL OR KHKY AND I HAVEN/T CARRIED ANYTHING AT THOSE SITES. CIGS WILL GRADUALLY LIFT AND MIX OUT DURING THE COURSE OF THE MORNING. OTHERWISE WINDS WILL BE OUT OF THE S TO SSW AGAIN TODAY AT SPEEDS UNDER 10 KTS. OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY. HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM THE TN VALLEY. CONFIDENCE TABLE... 08-14Z 14-20Z 20-02Z 02-08Z KCLT HIGH 93% HIGH 93% HIGH 100% HIGH 100% KGSP HIGH 87% HIGH 80% HIGH 100% HIGH 100% KAVL HIGH 98% HIGH 100% HIGH 100% HIGH 95% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 90% KGMU HIGH 87% HIGH 80% HIGH 100% HIGH 100% KAND HIGH 81% HIGH 81% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...LEV NEAR TERM...MCAVOY SHORT TERM...ARK LONG TERM...ARK AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
318 AM EDT THU MAY 30 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED PATTERN. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS RUNNING ABOUT A CATEGORY ABOVE NORMAL. WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN NC. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC. MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO GOING WITH A DRY FCST. ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL. OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA FOR SUNDAY INTO EARLY NEXT WEEK. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN. EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE NORMAL OVERNIGHT TEMPS. THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS WILL BE NEAR NORMAL. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... AT KCLT...MODEL GUIDANCE AND PERSISTANCE FROM LAST NIGHT IMPLIES THAT STRATUS WILL DEVELOP DOWN ACROSS THE MIDLANDS AND CLOSER TO THE MOUNTAINS TOWARD MORNING. IT/S A TOUGH CALL...BUT KCLT MAY NOT ACTUALLY SEE A CIG LATER TONIGHT. THEREFORE I/VE BACKED OFF THE BKN CIG AND GONE SCT010 STARTING AT 10 UTC. THE NAM BUFKIT SOUNDINGS APPEAR TO BE CAPPED AND NOT SUPPORTIVE OF A CU FIELD IN THE AFTN. I THINK THAT/S A HAIR OVERDONE AND I DO KEEP FEW040 AROUND DURING THE AFTN. WINDS WILL BE LIGHT OUT OF THE S TO SSW THROUGH THE DAY. ELSEWHERE...PER THE SREF PROBS OF CIGS LOWER THAN 3KFT AND THE AREA OF HIGHEST LLVL RH ON THE RUC AND PERSISTANCE WITH LAST NIGHT...WE SHOULD SEE STRATUS DEVELOP OVER NORTH CENTRAL GA STARTING IN AN HOUR OR TWO. IT SHOULD EXPAND NORTHEAST WITH TIME...AND SHOULD EVENTUALLY WORK ACROSS THE UPSTATE TAF SITES. EXACTLY WHEN THIS HAPPENS ISN/T AN EASY CALL. FOR NOW I HAVE MVFR CIGS DEVELOPING AT 10 UTC AT KAND AND NOT TIL 12 UTC AT KGSP. HOPEFULLY THAT WILL BE CLOSE. I/M LESS CONFIDENT OF STRATUS AT KAVL OR KHKY AND I HAVEN/T CARRIED ANYTHING AT THOSE SITES. CIGS WILL GRADUALLY LIFT AND MIX OUT DURING THE COURSE OF THE MORNING. OTHERWISE WINDS WILL BE OUT OF THE S TO SSW AGAIN TODAY AT SPEEDS UNDER 10 KTS. OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY. HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM THE TN VALLEY. CONFIDENCE TABLE... 07-13Z 13-19Z 19-01Z 01-07Z KCLT HIGH 100% HIGH 85% HIGH 100% HIGH 100% KGSP HIGH 96% MED 72% HIGH 100% HIGH 100% KAVL HIGH 96% HIGH 100% HIGH 100% HIGH 97% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 94% KGMU HIGH 96% MED 72% HIGH 100% HIGH 100% KAND HIGH 89% MED 76% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...LEV NEAR TERM...MCAVOY SHORT TERM...ARK LONG TERM...ARK AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
131 AM EDT THU MAY 30 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND... AND A COLD FRONT APPROACHES BY EARLY NEXT WEEK... RETURNING US TO AN UNSETTLED PATTERN. && .NEAR TERM /THROUGH TODAY/... AS OF 0130 AM EDT THURSDAY...SCT TO BKN STRATO-CU CONTINUE TO DEVELOP ALONG THE BLUE RIDGE. UPPED SKY COVER TO ACCOUNT FOR THAT. BASED ON THE SREF...RUC AND PERSISTENCE WITH LAST NIGHT I/VE UPPED SKY COVER TOWARD MORNING AND BROUGHT A STRATUS DECK ACROSS NE GA...THE NORTHERN AND WRN UPSTATE AND THE SRN NC MTNS...SOUTH OF ASHEVILLE. AS OF MID EVENING...FORECAST LOOKS LIKE IT IS IN GOOD SHAPE. NO CHANGES PLANNED. REMAINDER OF PREVIOUS DISCUSSION... CLOUDS SHUD DIMINISH THIS EVENING WITH LOSS OF HEATING. EXPECT ANOTHER ROUND OF LOW CLOUDS TO DEVELOP ACROSS THE SRN AND WRN CWFA NEAR DAYBREAK GIVEN THE CONTINUED MOIST SLY LOW LEVEL FLOW AND SUBSIDENCE INVERSION. EXPECT MOST OF THE NC PIEDMONT TO ONLY SEE SCT CLOUDS BY MORNING...BUT THE CLOUDY SKIES COULD CREEP FARTHER NORTH. THE CLOUDS SHUD SLOWLY LIFT AND SCATTER OUT THRU THE MORNING THU WITH MOSTLY SUNNY SKIES EXPECTED FOR AFTERNOON. WITH RIDGING SFC AND ALOFT...AND ASSOCIATED SUBSIDENCE INVERSION... REMAINING IN PLACE ACROSS THE AREA THU...DO NOT EXPECT ANY DEEP CONVECTION TO DEVELOP DURING THE AFTERNOON...EVEN OVER THE MTNS. LOWS TONIGHT SHUD BE NEAR TO SLIGHTLY ABOVE NORMAL. HIGHS THU SHUD RISE TO AS MUCH AS 5 DEGREES ABOVE NORMAL. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... AS OF 205 PM WEDNESDAY...UPPER RIDGE WILL REMAIN CENTERED/SITUATED IN THE VICINITY OF THE VA COAST WITH ONLY A SLOW TRANSITION TO THE EAST THROUGH SAT. AT THE SURFACE...THE BURMUDA HIGH WILL REMAIN RIDGED WESTWARD INTO THE SE U.S.. THEREFORE...GENERALLY DRY AND VERY WARM WEATHER WILL CONTINUE IN THE SHORT TERM. MODELS ARE GENERALLY LACKING IN QPF RESPONSE THU NIGHT THRU SAT. THIS MAKES SENSE IN THAT FCST SNDGS CONTINUE TO FEATURE A SUBSIDENCE INVERSION. THE EXCEPTION TO THE GENERAL LACK OF CONVECTION MAY BE FRI EVENING OVER THE MOUNTAINS AS MODEL TIME HEIGHTS SHOW LOW LEVEL MOISTURE INCREASING DUE TO THE SE FLOW OFF THE ATLANTIC WHICH MAY ALLOW PARCELS TO OVERCOME THE CAP IN UPSLOPE AREAS. HENCE...HAVE SOME ISOLATED/WIDELY SCT POPS FRI NIGHT IN THE MOUNTAINS TO ACCOUNT FOR THIS. A FEW ISOLD CELLS CANNOT BE RULED OUT IN THE MTNS AGAIN SAT AFTERNOON.. HIGHS WILL CONTINUE TO BE A CATEORY OR TWO ABOVE NORMAL BOTH DAYS. OVERNIGHT LOWS WILL BE QUITE MILD AS THE MOIST/PERSISTENT SELY FLOW OFF THE ATLANTIC IS LIKELY TO PRODUCE SOME MORNING STRATUS BOTH FRI AND SAT MORNINGS. THIS IS MOST LIKELY TO OCCUR IN THE WESTERN HALF OF THE CWFA. ANY LOW CLOUDS SHUD QUICKLY SCATTER OUT BY MIDDAY BOTH DAYS. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 200 PM WEDNESDAY...LOOKS LIKE AN ACTIVE PATTERN WILL BE IN PLAY OVER THE EXT RANGE. THE LATEST OP MODELS AGREE DECENTLY WITH THE ULVL FLOW AND UPSTREAM TROF CONFIG BEGINNING THE PERIOD AND WITH THE GENERAL PROPAGATION AND STRENGTH OF THE SYNOPTIC WAVE EASTWARD. THERE ARE ENOUGH DIFFERENCES IN THE DETAILS HOWEVER TO HAVE MODERATE OR A BIT LOWER CONFIDENCE IN THE SENSIBLE WX OVER THE PERIOD. THE 12Z GFS IS A SLOWER OUTLIER AND THE GEFS MEAN GIVES SUPPORT TO THE QUICKER ECMWF...THUS A BLEND OF THE OP MODELS AND WPC GUIDANCE WAS USED FOR OVERALL TIMING AND THE WEAKENING TROF. THE PERIOD BEGINS WITH MOIST ATL FLOW CONTINUING ACROSS THE REGION AND A FEW UPSLOPE -SHRA/TSTMS SHOULD BE WANING THROUGH SAT NIGHT. AS THE UPPER TROF IMPINGES...ULVL DIV WILL INCREASE AND AIDE IN THUNDER ACTIVITY SUN AFTERNOON. NOT MUCH OF A DISTINCT SFC CONVERGENCE ZONE IS NOTED...SO WILL EXPECT MOST OF THE ACTIVITY ACROSS THE NC MTNS WHERE LIKELY POPS HAVE BEEN INTRODUCED. SOUNDINGS SHOW A DEEP CONVECTIVE POTENTIAL WITH LOW END SBCAPE DEVELOPING AS THE WEAKENING ULVL VORT WAVE CROSSES OVERHEAD. SO...EXPECT PRETTY GOOD COVERAGE IN THE MTNS...WITH ISOL/SCT STORMS DEVELOPING TO THE EAST THROUGH THE AFTERNOON....THEN LIKELY COVERAGE MOST LOCALES AS THE WAVE MOVES EAST OVERNIGHT. THERE REMAINS A FAIR AMOUNT OF UNCERTAINTY MON WRT TO THE FRONTAL PLACEMENT...AND WILL COUNT THE FRONT JUST MOVING INTO THE MTNS BY MID DAY. SO...ANOTHER DAY OF GOOD HEATING AND INSTABILITY WILL GENERATE TSTMS. THE GFS SLOWS THE FRONT DOWN AS IT LOSES MUCH ULVL SUPPORT AND KEEPS THINGS ACTIVE MON NIGHT INTO TUE...WHILE THE ECMWF AND THE WPC HAVE THE FRONT NEAR THE ATL COAST BY 12Z TUE. WITH THIS MUCH UNCERTAINTY...HAVE ALIGNED CHANCE POPS TO FAVOR THE ERN ZONES LATE MON THROUGH TUE. THERE IS GOOD AGREEMENT WITH A MOIST WEDGE DEVELOPING TUE NIGHT AND PERSISTING THROUGH TH PERIOD. THIS WOULD KEEP MAX TEMPS A CAT OR SO BELOW NORMAL WED AND POSSIBLY THU. MAX TEMPS SUN THROUGH TUE SHOULD BE A FEW DEGREES ABOVE NORMAL WITH WARM SECTOR FLOW REMAINING OVER THE REGION. WITH ALL THE NOCTURNAL CLOUDINESS EXPECTED...MINS SHOULD ALSO BE A COUPLE DEGREES ABOVE NORMAL THROUGH TUE MORNING BEFORE THE WEDGE BUILDS IN. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AT KCLT...MODEL GUIDANCE AND PERSISTANCE FROM LAST NIGHT IMPLIES THAT STRATUS WILL DEVELOP DOWN ACROSS THE MIDLANDS AND CLOSER TO THE MOUNTAINS TOWARD MORNING. IT/S A TOUGH CALL...BUT KCLT MAY NOT ACTUALLY SEE A CIG LATER TONIGHT. THEREFORE I/VE BACKED OFF THE BKN CIG AND GONE SCT010 STARTING AT 10 UTC. THE NAM BUFKIT SOUNDINGS APPEAR TO BE CAPPED AND NOT SUPPORTIVE OF A CU FIELD IN THE AFTN. I THINK THAT/S A HAIR OVERDONE AND I DO KEEP FEW040 AROUND DURING THE AFTN. WINDS WILL BE LIGHT OUT OF THE S TO SSW THROUGH THE DAY. ELSEWHERE...PER THE SREF PROBS OF CIGS LOWER THAN 3KFT AND THE AREA OF HIGHEST LLVL RH ON THE RUC AND PERSISTANCE WITH LAST NIGHT...WE SHOULD SEE STRATUS DEVELOP OVER NORTH CENTRAL GA STARTING IN AN HOUR OR TWO. IT SHOULD EXPAND NORTHEAST WITH TIME...AND SHOULD EVENTUALLY WORK ACROSS THE UPSTATE TAF SITES. EXACTLY WHEN THIS HAPPENS ISN/T AN EASY CALL. FOR NOW I HAVE MVFR CIGS DEVELOPING AT 10 UTC AT KAND AND NOT TIL 12 UTC AT KGSP. HOPEFULLY THAT WILL BE CLOSE. I/M LESS CONFIDENT OF STRATUS AT KAVL OR KHKY AND I HAVEN/T CARRIED ANYTHING AT THOSE SITES. CIGS WILL GRADUALLY LIFT AND MIX OUT DURING THE COURSE OF THE MORNING. OTHERWISE WINDS WILL BE OUT OF THE S TO SSW AGAIN TODAY AT SPEEDS UNDER 10 KTS. OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY. HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM THE TN VALLEY. CONFIDENCE TABLE... 05-11Z 11-17Z 17-23Z 23-05Z KCLT HIGH 100% HIGH 85% HIGH 100% HIGH 100% KGSP HIGH 100% MED 73% HIGH 100% HIGH 100% KAVL HIGH 97% HIGH 94% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% MED 73% HIGH 100% HIGH 100% KAND HIGH 100% MED 72% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...LEV NEAR TERM...MCAVOY SHORT TERM...LG LONG TERM...SBK AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1237 AM CDT THU MAY 30 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 404 PM CDT WED MAY 29 2013 COMPLEX SCENARIO TONIGHT BUT THE OVERALL MESSAGE LOOKS TO BE A LOW END THREAT FOR SEVERE THUNDERSTORMS WITH A BETTER THREAT FOR LOCALIZED HEAVY RAINFALL. CONVECTION CONTINUES TO SKIRT ALONG THE WESTERN AND EASTERN EDGES OF THE CWA AS CONVECTION IN NEBRASKA CONTINUES TO WEAKEN AS IT MOVES NORTH. SHEAR VALUES ARE MINIMALLY SUPPORTIVE OF SEVERE CONVECTION WHILE CAPE VALUES ARE AROUND 1000 TO 1500 J/KG BUT OF THE VERY SKINNY VARIETY. THUS STARTING TO TREND THINKING TOWARDS THE CONSISTENT HRRR WHICH FOR 5 RUNS IN A ROW HAS PRODUCED A LARGE MCS WHICH CONGEALS FROM THE CONVECTION THAT IS CURRENTLY DEVELOPING OVER THE WESTERN HIGH PLAINS. WILL RUN A BLEND OF HPC/LOW RESOLUTION MODELS ALONG WITH THE HRRR AND RAP OUTPUT. THE MAIN TAKE FROM THIS IS THAT THERE STILL APPEARS TO BE THE THREAT FOR STORMS TO PRODUCE LOCALIZED RAINFALL AMOUNTS OF 3 TO 4 INCHES WITH SLOW STORM MOVEMENT. WITH MOST LOCATIONS FLASH FLOOD GUIDANCE RIGHT AROUND AN INCH AND A HALF OR A LITTLE MORE FLASH FLOODING WILL BE A THREAT. THERE IS LIKELY TO BE A LULL IN CONVECTIVE ACTIVITY LATE TONIGHT INTO TOMORROW MORNING THEN THE POTENTIAL FOR MORE THUNDERSTORMS TOMORROW AFTERNOON...ESPECIALLY IN NORTHWEST IOWA AND MAINLY SOUTHEAST PARTS OF SOUTHWEST MINNESOTA. CAPE VALUES JUST A BIT MORE STOUT TOMORROW AND WIND SHEAR JUST A TOUCH BETTER SO AGAIN NOT A WIDESPREAD THREAT BUT A THREAT NONETHELESS. LOWS TONIGHT MAINLY 60 TO 65 WITH HIGHS ON THURSDAY IN THE MID 70S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 404 PM CDT WED MAY 29 2013 LINGERING CONVECTION FROM DEVELOPMENT ON THURSDAY AFTERNOON WILL BE SWINGING FAIRLY RAPIDLY THROUGH WITH STRONG PV LOBE LIFTING TO THE NORTHEAST. MAIN UPPER WAVE WILL BE FAIRLY SLOW TO WOBBLE THROUGH THE DAKOTAS THROUGH EARLY IN THE WEEKEND...BUT FIRST PART OF THIS PERIOD WILL INTRODUCE A DRY SLOT AHEAD OF UPPER CIRCULATION THURSDAY NIGHT INTO EARLY FRIDAY. AREA OF DIV Q BRUSHES UP AGAINST THE FAR SOUTHEAST LATE AND WHILE BEST CHANCE FOR PRECIPITATION WILL CONTINUE WELL SOUTHEAST...DID NUDGE A SMALL CHANCE FOR A LIGHT SHOWER INTO THE FAR SOUTHEAST FOR A FEW HOURS AROUND DAYBREAK ON FRIDAY. IN GENERAL...THE DRIER AIR WILL WORK THROUGH AREAS SOUTH OF THE UPPER LOW AND WITH DIMINISHING WINDS ON THURSDAY NIGHT...WILL FIND LOWS BACK IN THE UPPER 40S TO LOWER 50S FOR MOST. SEVERAL DETERMINISTIC MODELS INDICATE A WEAK CONVERGENCE BOUNDARY SLIDING THROUGH THE AREA ON LATER FRIDAY AFTERNOON AND FRIDAY EVENING. AIRMASS DOES GET SOMEWHAT UNSTABLE...AND APPEARS TO BE SETUP FOR DECENT MIXING WITH THE WEST TO SOUTHWEST FLOW COMPONENT AT LOWER LEVELS THROUGH THE DAY. NET EFFECT WILL LIKELY BE AN ALMOST UNCAPPED PROFILE WITH 400-700 J/KG INSTABILITY AND UNIMPRESSIVE SHEAR. LIKELY WILL BE THE UNFAVORABLE AND WEAKLY SUBSIDENT LARGER SCALE THAT WILL KEEP ACTION AT BAY UNTIL LATER INTO THE DIURNAL CYCLE...WHEN PERHAPS SOME WEAK LOW LEVEL MOISTURE POOLING DUE TO INDUCING SOMEWHAT STRONGER CONVERGENCE THAN MODEL INDICATED. STILL WILL BE FAIRLY ISOLATED TO SCATTERED EVEN IT DOES DEVELOP WITH MOISTURE LIMITATIONS. AFTER VERY SHORT TERM...LOOKS LIKE LATER FRIDAY NIGHT INTO SATURDAY WILL BE THE BEST CHANCE FOR PRECIPITATION ACROSS THE AREA...ALBEIT MUCH LIGHTER THAN SHORTEST RANGE PRECIPITATION. UPPER TROUGH SWINGS PAST WITH VERY COOL TEMPERATURES ALOFT. SHOULD BE PLENTY OF LOWER LEVEL SHOWERS EVEN BEHIND PASSAGE OF UPPER WAVE ON SATURDAY AFTERNOON WHICH CONTINUE TO ROTATE THROUGH NORTHEASTERN CWA. BLUSTERY AND COOL DAY...WITH HIGHS UPPER 50S TO MID 60S. GFS ENSEMBLE TEMPERATURE GUIDANCE STRONGLY SUGGESTS THAT COOLER IS BETTER FOR SATURDAY. WINDS WILL DIMINISH...BUT A COOL NIGHT ON SATURDAY NIGHT AS CLEARING PUSHES INTO THE WEST HALF. FOR THE EXTENDED RANGE /SUNDAY THROUGH WEDNESDAY/ A FAIRLY QUIET START WITH BRIEF RIDGING IN PLACE. STRETCHED OUT THE DIURNAL RANGE A BIT FROM INITIALIZATION...AS EVEN WITH WET GROUND SHOULD BE ABLE TO GET TOWARD FULL 850 HPA MIXING ON SUNDAY. DEVELOPMENT OF RETURN FLOW FROM WEST TO EAST ON SUNDAY NIGHT INTO MONDAY MORNING. GFS/ECMWF SHOWING SOME WEAK ELEVATED INSTABILITY/MOISTURE RETURN BY LATER MONDAY...AND RELUCTANTLY INTRODUCED A LOW CHANCE FOR THUNDERSTORMS. ANOTHER UPPER TROUGH WILL SETTLE INTO THE NORTHERN PLAINS TUESDAY INTO WEDNESDAY...BUT THIS SOURCE WILL BE WITHIN LARGER SCALE NORTHWEST FLOW AND IS SOMEWHAT MORE PROGRESSIVE THAN SHORT TERM SYSTEM. SOME UNCERTAINTY IN TIMING AS BOUNDARY PUSHES THROUGH THE AREA BUT HIGHEST CHANCES APPEAR CURRENTLY TO WORK THROUGH DURING THE MONDAY NIGHT THROUGH TUESDAY NIGHT PERIOD. GENERALLY...TEMPERATURES WILL BE WORKING SLOWLY UPWARD THROUGH TUESDAY...THEN SLIPPING BACK A TOUCH WITH BOUNDARY PASSAGE AND PRECIPITATION LATER TUESDAY INTO WEDNESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1237 AM CDT THU MAY 30 2013 WITH LOWER LEVELS HAVING DRIED OUT IN INCREASING SOUTHERLY FLOW...VFR IS NOW EXPECTED TO BE GENERAL EXCEPT FOR A PERIOD OF CEILINGS 1-3K FEET SOUTH AND EAST OF FSD 09Z-15Z. OTHERWISE A FEW AREAS OF THESE MVFR CONDITIONS WILL BE POSSIBLE IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH 15Z. 15Z-31/01Z VFR EXCEPT LOCAL AND BRIEF CEILINGS 2-3K FEET AND VISIBILITIES 3-5SM IN ISOLATED TSRA EAST AND SOUTH OF FSD. AFTER 01Z VFR OVER AREA. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR IAZ002-003- 012>014-020>022-031-032. NE...FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR NEZ014. && $$ SHORT TERM...08 LONG TERM...CHAPMAN AVIATION...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
333 AM CDT THU MAY 30 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 333 AM CDT THU MAY 30 2013 CURRENTLY AS OF 0830Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED UPPER TROUGHING FROM THE NORTHEAST PACIFIC INTO THE NORTHERN ROCKIES WITH AN UPPER LOW IN NORTHEAST WYOMING...WHILE DOWNSTREAM RIDGING WAS PRESENT ACROSS THE EASTERN U.S.. ALSO TO NOTE ON WATER VAPOR IS A FAIRLY POTENT SHORTWAVE OVER THE TEXAS AND OKLAHOMA PANHANDLES IN THE BASE OF THIS TROUGHING. NEARLY UNIDIRECTIONAL SOUTH TO SOUTHWEST FLOW EXISTED BETWEEN THE TROUGHING AND RIDGING... WITH SOME VERY STRONG WINDS AT 850MB. VWP AND PROFILER DATA SHOWED SPEEDS OF 50-65 KT FROM CENTRAL OKLAHOMA INTO SOUTHERN MINNESOTA. THESE WINDS WERE TRANSPORTING COPIOUS AMOUNTS OF MOISTURE NORTHWARD...NOTED BY PRECIPITABLE WATER VALUES OF 1.5-1.75 INCHES OR 150-180 PERCENT OF NORMAL. NUMEROUS SHORTWAVES...SOME CONVECTIVELY INDUCED...RIDING THROUGH THE MID LEVEL FLOW HAS BEEN INTERACTING WITH THE MORE SUMMER-LIKE AIRMASS TO CONTINUE TO PRODUCE SCATTERED CLUSTERS OF SHOWERS AND THUNDERSTORMS. MUCH OF THE FORECAST AREA LIES IN THE WARM SECTOR OF A LOW PRESSURE SYSTEM BACK IN THE DAKOTAS. MAIN WARM FRONT HAS LIFTED INTO NORTHERN WISCONSIN WHILE THE COLD FRONT IS WELL BACK TO THE WEST IN CENTRAL SOUTH DAKOTA. MODELS ARE IN GOOD AGREEMENT ON THE SYNOPTICS THROUGH TONIGHT... INDICATING THAT THE UPPER TROUGHING FROM WYOMING INTO THE TEXAS PANHANDLE WILL SHIFT EAST NORTHEAST INTO THE FORECAST AREA BY 06Z TONIGHT. THERE ARE SOME DECENT 500MB HEIGHT FALLS BETWEEN 18Z-06Z OVER THE FORECAST AREA...ON THE ORDER OF 60-90 METERS. THE DPVA FROM THE APPROACH OF THIS UPPER TROUGH...AS WELL AS VARIOUS SHORTWAVES AND CONVECTIVELY INDUCED SHORTWAVES AHEAD OF IT...SUGGESTS PLENTY OF FORCING FOR CONVECTION. MODELS HAVE SHOWN THIS FOR MANY DAYS AS WELL. THIS FORCING MAY MAKE IT HARD TO BUILD A LOT OF INSTABILITY... COMPARED TO YESTERDAY WHERE WE HAD PLENTY OF SUNSHINE BEFORE CONVECTION ERUPTED. RAP/NAM/GFS SOUNDINGS ALL SUGGEST ANY 0-1 MLCIN FROM NOCTURNAL INFLUENCES BEING NEARLY COMPLETELY GONE BY 15Z. THEREFORE IT IS CONCEIVABLE FOR CONVECTION TO FIRE SHORTLY THEREAFTER WHEN 0-1 MLCAPE IS ONLY AT 800-1500 J/KG. HRRR/RAP MODELS SHOW CONVECTION FIRING IN THAT 15-16Z WINDOW...IN AGREEMENT WITH THE ABOVE ANALYSIS. THE CONVECTION MAY STABILIZE THINGS BRIEFLY...BUT PERSISTENT HEATING THROUGH THE DAY COMBINED WITH SOUTHERLY WARM ADVECTION OF INSTABILITY SHOULD PROVIDE FUEL TO CONTINUE PERIODS OF CONVECTION THROUGH THE DAY AND INTO THE EVENING. PASSAGE OF THE UPPER TROUGH AND NOCTURNAL COOLING SHOULD ALLOW CONVECTION TO SUBSIDE AFTER MIDNIGHT. REGARDING SEVERE POTENTIAL...THE LIMITATION OF BUILDING A LOT OF CAPE IS A HINDRANCE. 0-6KM SHEAR FROM THE 30.00Z NAM/GFS IS GENERALLY PROGGED AT 25-30 KT THROUGH THE DAY...FAVORING FOR MORE OF A MULTI-CELL SITUATION. WITH INSTABILITY STRUGGLING...NOT THINKING MUCH IN THE WAY FOR SEVERE HAIL. BULK OF THE AFOREMENTIONED 0-6KM SHEAR IS IN THE 0-3KM LAYER...AND COMBINED WITH 850MB WINDS PROGGED IN THE AFTERNOON AND EVENING OF 45-50 KT DOES BRING UP A CONCERN FOR THE STORMS TO PRODUCE STRONG TO DAMAGING WIND GUSTS. 0-1KM SHEAR IS QUITE HIGH AS WELL FOR THE AFTERNOON AND EVENING...SIMILAR TO 0-3KM OF 25-30KT...SO WE MAY WANT TO WATCH FOR POSSIBLE TORNADOES TOO. THIS WOULD BE ESPECIALLY TRUE ALONG ANY CONVECTIVE OUTFLOW BOUNDARY AND/OR IF WE CAN GET MORE DAYTIME HEATING THAN EXPECTED. ON THE FLOODING FRONT...MORE INFORMATION CAN BE FOUND IN THE HYDROLOGY SECTION BELOW. BRIEFLY...THE PATTERN TODAY INTO THIS EVENING IS VERY FAVORABLE FOR STORMS TO TRAIN ACROSS THE SAME AREAS AS THEY MARCH SOUTH TO NORTH. WITH PRECIPITABLE WATER VALUES STAYING UP IN THE 1.5-1.75 INCH RANGE ANY STORM CAN PRODUCE HEAVY RAIN. WITH GROUNDS ALREADY SATURATED...FLASH FLOODING IS CERTAINLY POSSIBLE... ESPECIALLY SOUTH OF I-90 WHICH WAS REALLY IMPACTED FROM YESTERDAY INTO LAST NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 333 AM CDT THU MAY 30 2013 LOW PRESSURE OVER THE EASTERN DAKOTAS PUSHES SOUTHEAST LATE FRIDAY MORNING INTO FRIDAY AFTERNOON DRIVING THE FRONT ACROSS THE FORECAST AREA. DEPENDING ON THE TIMING OF THIS FRONT...SEVERE WEATHER POSSIBLE ON FRIDAY. FORECAST MODELS ARE IN REASONABLE AGREEMENT...SHOWING 0-3 KM MUCAPE VALUES CLIMBING TO 2000 TO 3000 J/KG. SHEAR IS ALSO RAMPING UP LATE FRIDAY MORNING INTO FRIDAY AFTERNOON WITH 0-6 KM BULK SHEAR INCREASING TO 45 TO 55 KTS. THE HIGHEST INSTABILITY APPEARS TO BE OVER FAR NORTHEAST IOWA AND INTO EXTREME SOUTHWEST WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON THIS OVER THE NEXT FEW MODEL RUNS. AT THIS TIME...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN HAZARDS FROM THESE STORMS. BUT AGAIN...THE SEVERE THREAT AREA WILL DEPEND ON WHERE THE BOUNDARY IS LOCATED LATE FRIDAY MORNING INTO FRIDAY AFTERNOON AND HOW MUCH SURFACE HEATING IS REALIZED. A DRY SLOT PUSHES INTO THE FORECAST AREA LATE FRIDAY NIGHT AS THE LOW PUSHES EAST INTO THE WESTERN GREAT LAKES. THERE SHOULD BE A DRY PERIOD AS THE LOW MOVES IN...BUT THEN SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP ON SATURDAY AS THE LOW SLIDES ACROSS THE REGION. AN UNSEASONABLY COOL AIRMASS MOVES INTO REGION ON SUNDAY. 850 MB TEMPERATURES FALL TO 0 C OVER NORTHERN WISCONSIN AND TO AROUND 2 C OVER NORTHEAST IOWA. THIS WILL SET THE STAGE FOR A CHILLY NIGHT ACROSS THE AREA SUNDAY NIGHT INTO EARLY MONDAY MORNING. ECMWF 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO AROUND -1.5...INDICATIVE OF AN ANOMALOUSLY COLD AIRMASS. TEMPERATURES WILL PLUMMET INTO THE UPPER 30S OVER FAR NORTHERN WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON LOWS OVER NORTH CENTRAL AND CENTRAL WISCONSIN WHERE TYPICAL COLD SPOTS SUCH AS SPARTA AND BLACK RIVER FALLS COULD SEE LOWS DIP INTO THE UPPER 30S...LEADING TO FROST FORMATION. COOL HIGH PRESSURE REMAINS OVER THE REGION THROUGH TUESDAY...WITH HIGHS ONLY IN THE 60S. HIGH PRESSURE PUSHES EAST OF THE REGION LATE TUESDAY INTO WEDNESDAY AS A TROUGH DIGS INTO THE DAKOTAS. SOUTHERLY FLOW DEVELOPS OVER THE AREA HELPING TO USHER IN WARMER TEMPERATURES. THE TROUGH WILL MOVE INTO THE FORECAST AREA LATE TUESDAY NIGHT THROUGH WEDNESDAY BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1159 PM CDT WED MAY 29 2013 CLUSTERS OF SHOWERS AND SCATTERED THUNDERSTORMS CONTINUE TO AFFECT THE TAF SITES AS OF 05Z...BUT THEY ARE LIFTING NORTH. WITH DIMINISHING INSTABILITY THROUGH THE EARLY MORNING HOURS...THINKING ONLY A FEW MORE HOURS OF PRECIPITATION WILL OCCUR. VISIBILITIES FOR THE MOST PART HAVE BEEN VFR...SO FOR NOW HANDLED THE TAFS WITH VCSH. CEILINGS ARE ALSO HOLDING VFR AND SHOULD PERSIST THROUGH THE REST OF THE NIGHT AS A SOUTHERLY BREEZE KEEPS THINGS MIXED. REGARDING THAT SOUTHERLY BREEZE...40-50 KT WINDS ARE PRESENT 1000-2000 FT ABOVE THE GROUND. RECENT RAIN HAS ALLOWED WINDS AT THE SURFACE TO BE LIGHTER THAN EXPECTED...ESPECIALLY AT KLSE...THUS HAVE INCLUDED LOW LEVEL WIND SHEAR. MORE SHOWER AND THUNDERSTORM ACTION SHOULD INITIATE A FEW HOURS AFTER SUNRISE AS INSTABILITY INCREASES. ENOUGH CONFIDENCE EXISTS TO HAVE A LONG PERIOD OF VCTS AT BOTH TAF SITES...FROM 17Z-02/03Z AS PLENTIFUL FORCING EXISTS FOR OFF AND ON THUNDERSTORM ACTIVITY. VISIBILITIES COULD BE TEMPORARILY REDUCED AS WELL...BUT NOT ENOUGH CONFIDENCE EXISTS TO INCLUDE THIS IN THE FORECAST. CEILINGS SHOULD HOLD VFR...AIDED BY DAYTIME HEATING. THIS SAME DAYTIME HEATING WILL MIX THE STRONG AFORMENTIONED WINDS DOWN TO THE SURFACE...THUS GUSTS OF 25-30 KT APPEAR LIKELY FOR THE AFTERNOON INTO THE EARLY EVENING HOURS. THESE COULD BE EVEN HIGHER IF MORE SUN OCCURS. BOTH WINDS AND THUNDERSTORM ACTIVITY SHOULD DIMINISH DURING THE EVENING WITH LOSS OF HEATING. && .HYDROLOGY...TODAY AND TONIGHT ISSUED AT 333 AM CDT THU MAY 30 2013 HEAVY RAIN FELL ACROSS THE AREA WEDNESDAY AFTERNOON AND EVENING WITH RAINFALL AMOUNTS OF 2 TO 3 INCHES REPORTED ACROSS PORTIONS OF NORTHEAST IOWA...SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN...WITH LOCALLY HIGHER AMOUNTS OF 4 INCHES REPORTED. AN ADDITIONAL 1 TO 2 INCHES OF RAIN IS EXPECTED ACROSS THE AREA TODAY THROUGH THIS EVENING...WHICH COULD LEAD TO FLASH FLOODING. IT WILL NOT TAKE MUCH RAIN OVER THE SATURATED SOILS TO CREATE FLOODING ISSUES. ALSO...AREA RIVERS WILL SEE RISES AND POSSIBLE FLOODING WITH ANY ADDITIONAL RAINFALL RECEIVED. HAVE EXPANDED THE FLASH FLOOD WATCH NORTHWARD...INCLUDING AREAS ALONG AND SOUTHWEST OF INTERSTATE 94 CORRIDOR EXCLUDING JUNEAU COUNTY && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WIZ032>034-041-042- 053>055-061. MN...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR IAZ008>011-018-019- 029-030. && $$ SHORT TERM...AJ/WETENKAMP LONG TERM...WETENKAMP AVIATION...AJ HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1159 PM CDT WED MAY 29 2013 .UPDATE... ISSUED AT 714 PM CDT WED MAY 29 2013 HAVE EXPANDED THE FLASH FLOOD WATCH EVEN FARTHER EAST TO NOW INCLUDE VERNON...CRAWFORD...RICHLAND AND GRANT COUNTIES IN WISCONSIN. CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN HAS ENTERED THESE COUNTIES. MEANWHILE...THE ENTIRE MCS OVER THE FORECAST AREA EXTENDING DOWN TO MARSHALLTOWN AND CEDAR RAPIDS IOWA SHOULD LIFT NORTH THROUGH THE NIGHT...IN RESPONSE TO STRENGTHENING LOW LEVEL JET / MOISTURE TRANSPORT. THIS MEANS THE EXPANDED FLASH FLOOD WATCH AREA COULD SEE PERIODS OF MODERATE TO HEAVY RAINFALL FOR AT LEAST THE NEXT FEW HOURS. UPDATE ISSUED AT 429 PM CDT WED MAY 29 2013 HAVE EXPANDED THE FLASH FLOOD WATCH EASTWARD TO INCLUDE HOUSTON...ALLAMAKEE AND CLAYTON COUNTIES. PRESENT CONVECTION TRACKING ACROSS WESTERN PORTIONS OF THE FORECAST AREA HAS BEEN MOVING MORE SLOWLY ACROSS NORTHEAST IOWA...PRIMARILY DUE TO LOWER 0-6KM SHEAR THERE. AS THIS CONVECTION MOVES INTO THE EXPANSION AREA...EXPECTING THE RAIN TO PRIME CONDITIONS FOR POSSIBLE FLASH FLOODING...EITHER FROM THE CURRENT CONVECTION OR FROM ADDITIONAL EXPECTED CONVECTION LATER TONIGHT INTO THURSDAY. ALSO STARTED THE FLASH FLOOD WATCH NOW GIVEN CURRENT CONVECTION AND THE NEED FOR WARNINGS SOONER THAN EXPECTED. && .SHORT TERM...(TONIGHT THROUGH THURSDAY) ISSUED AT 308 PM CDT WED MAY 29 2013 MAIN CONCERN IS SEVERE POTENTIAL GOING INTO THIS EVENING AND HEAVY RAINFALL POTENTIAL THROUGH THURSDAY. WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWS A DEEPENING TROUGH OF LOW PRESSURE ACROSS THE CENTRAL ROCKIES INTO THE SOUTHERN PLAINS. THIS IN TURN WAS DRIVING AN INCREASINGLY MOIST/UNSTABLE SOUTHERLY SURFACE FLOW FROM THE PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AT THE SURFACE LOW PRESSURE WAS LOCATED OVER SOUTHEAST CO WITH A WARM FRONT EXTENDING NORTHEAST THROUGH IA INTO SOUTHERN WI. CONVECTION/SOME STRONG TO SEVERE WAS FIRING ALONG/AHEAD OF THIS WARM FRONT ON THE NOSE OF INCREASING 925-85OMB MOISTURE TRANSPORT/INCREASING CAPE POOL. DEW POINTS ACROSS OUR AREA THIS AFTERNOON WERE IN THE MID/UPPER 60S WITH AROUND 70 ACROSS EASTERN IA. LOOK FOR ONGOING SHOWER/THUNDERSTORM ACTIVITY THIS EVENING AS THE WARM FRONT/NOSE OF RATHER INTENSE MOISTURE TRANSPORT CONTINUES TO PUSH NORTH ACROSS THE AREA. RAP SHOWING 0-1KM MLCAPE IN THE 3000-3500J/KG WITH INCREASING 0-3KM BULK SHEAR IN THE 25-35KT RANGE BETWEEN 4 PM AND 8 PM ACROSS PORTIONS OF NORTHEAST IA/SOUTHWEST WI. CAPE/BULK SHEAR AND ENHANCED 0-1KM EHI VALUES WOULD FAVOR TORNADOGENESIS ALONG THE WARM FRONT AS IT PUSHES THROUGH NORTHEAST IA/SOUTHWEST WI. WILL HAVE TO KEEP AN EYE ON LARGE HAIL/DAMAGING WIND/TORNADIC POTENTIAL GOING INTO EVENING. CAPE STARTS DWINDLING AFTER SUNSET...HOWEVER...MODELS CONTINUE TO SHOW FETCH OF STRONG 925-850MB MOISTURE TRANSPORT ADVECTING INTO OUR AREA OVERNIGHT INTO THURSDAY. THIS WILL BE AHEAD OF A COLD FRONT PUSHING EASTWARD INTO THE CENTRAL PLAINS. PRECIPITABLE WATER VALUES INCREASE INTO THE 1.5 TO 1.7IN RANGE. WITH THIS IN MIND THERE WILL BE THE POTENTIAL WILL BE THERE FOR SOME HEAVY RAINFALL. HAVE ISSUED A FLASH FLOOD WATCH FOR PORTIONS OF THE AREA THIS EVENING THROUGH THURSDAY TO COVER THIS. SEE THE HYDROLOGY SECTION BELOW FOR FURTHER DETAILS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 308 PM CDT WED MAY 29 2013 MAIN AXIS OF MOISTURE TRANSPORT/ENHANCED PRECIPITABLE WATER SHIFTS EAST OF THE AREA THURSDAY NIGHT WITH A COLD FRONT LAGGING ACROSS CENTRAL MN INTO EASTERN NEBRASKA/CENTRAL KS. SO...EXPECTING HEAVIER RAINFALL TO TAPER OFF IN THE EVENING/OVERNIGHT FROM WEST TO EAST. THE COLD FRONT WILL CONTINUE TO PUSH SLOWLY EAST INTO THE AREA FRIDAY WITH INCREASING MOISTURE TRANSPORT INTO FAR SOUTHERN WI DURING THE AFTERNOON. HAVE TAILORED SHRA/TS CHANCES WITH LIKELY ACROSS THE SOUTH...TAPERING TO 40-50 POPS ACROSS THE NORTHWEST. FOR FRIDAY NIGHT THROUGH SUNDAY...LOOK FOR A MID-LEVEL CLOSED LOW TO MAKE ITS WAY ACROSS THE AREA FOR SCATTERED SHOWERS AND COOLING TEMPERATURES. SUNDAY NIGHT THROUGH MONDAY LOOKS DRY AND COOL AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE PLAINS. SHOWER/THUNDERSTORM CHANCES RETURN TO THE AREA MONDAY NIGHT THROUGH WEDNESDAY AS ANOTHER CLOSED MID-LEVEL LOW SYSTEM DROPS ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGION. THIS SYSTEM WILL ALSO RESULT IN BELOW NORMAL TEMPERATURES THROUGH THIS PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1159 PM CDT WED MAY 29 2013 CLUSTERS OF SHOWERS AND SCATTERED THUNDERSTORMS CONTINUE TO AFFECT THE TAF SITES AS OF 05Z...BUT THEY ARE LIFTING NORTH. WITH DIMINISHING INSTABILITY THROUGH THE EARLY MORNING HOURS...THINKING ONLY A FEW MORE HOURS OF PRECIPITATION WILL OCCUR. VISIBILITIES FOR THE MOST PART HAVE BEEN VFR...SO FOR NOW HANDLED THE TAFS WITH VCSH. CEILINGS ARE ALSO HOLDING VFR AND SHOULD PERSIST THROUGH THE REST OF THE NIGHT AS A SOUTHERLY BREEZE KEEPS THINGS MIXED. REGARDING THAT SOUTHERLY BREEZE...40-50 KT WINDS ARE PRESENT 1000-2000 FT ABOVE THE GROUND. RECENT RAIN HAS ALLOWED WINDS AT THE SURFACE TO BE LIGHTER THAN EXPECTED...ESPECIALLY AT KLSE...THUS HAVE INCLUDED LOW LEVEL WIND SHEAR. MORE SHOWER AND THUNDERSTORM ACTION SHOULD INITIATE A FEW HOURS AFTER SUNRISE AS INSTABILITY INCREASES. ENOUGH CONFIDENCE EXISTS TO HAVE A LONG PERIOD OF VCTS AT BOTH TAF SITES...FROM 17Z-02/03Z AS PLENTIFUL FORCING EXISTS FOR OFF AND ON THUNDERSTORM ACTIVITY. VISIBILITIES COULD BE TEMPORARILY REDUCED AS WELL...BUT NOT ENOUGH CONFIDENCE EXISTS TO INCLUDE THIS IN THE FORECAST. CEILINGS SHOULD HOLD VFR...AIDED BY DAYTIME HEATING. THIS SAME DAYTIME HEATING WILL MIX THE STRONG AFORMENTIONED WINDS DOWN TO THE SURFACE...THUS GUSTS OF 25-30 KT APPEAR LIKELY FOR THE AFTERNOON INTO THE EARLY EVENING HOURS. THESE COULD BE EVEN HIGHER IF MORE SUN OCCURS. BOTH WINDS AND THUNDERSTORM ACTIVITY SHOULD DIMINISH DURING THE EVENING WITH LOSS OF HEATING. && .HYDROLOGY...TONIGHT THROUGH FRIDAY ISSUED AT 714 PM CDT WED MAY 29 2013 PERIODS OF SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF THE REGION THROUGH FRIDAY. THE HEAVIEST RAIN IS EXPECTED TO FALL FROM THURSDAY INTO FRIDAY. TOTAL RAINFALL FROM TODAY THROUGH FRIDAY COULD RANGE FROM 1 TO 3 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THIS COULD LEAD TO FLASH FLOODING AS WELL AS RISES AND POSSIBLE FLOODING ON AREA RIVERS. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR NORTHEAST IA AND PORTIONS OF SOUTHEAST MN AND SOUTHWEST WISCONSIN THROUGH THU. THIS MAY NEED TO BE EXPANDED NORTHWARD AS DETAILS OF TIMING/LOCATION OF THE CONTINUED HEAVY RAIN THREAT BECOME CLEARER. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR WIZ053>055-061. MN...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR MNZ094>096. IA...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR IAZ008>011-018- 019-029-030. && $$ UPDATE...AJ SHORT TERM...DAS LONG TERM....DAS AVIATION...AJ HYDROLOGY....DAS/AJ
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
845 AM PDT THU MAY 30 2013 .DISCUSSION...AS OF 08:31 AM PDT THURSDAY... FORECAST LOOKS ON TRACK THIS MORNING WITH EARLY MORNING TEMPERATURES A FEW DEGREES COOLER THAN YESTERDAY AT THIS TIME. GOOD RADIATIONAL COOLING NIGHT WITH LESS STRATUS THIS MORNING. WRF MODEL CAPTURED BOUNDARY LAYER RH FIELD PRETTY WELL THIS MORNING AND RESULTANT AREAS OF STRATUS. MODEL TRENDS TOWARD RAPID STRATUS CLEARING THIS MORNING...BUT LOOKING AT VISIBLE SATELLITE IMAGERY WOULD SUGGEST SLIGHTLY SLOWER CLEARING. SAN MATEO COAST AND WEST SLOPES OF COAST RANGE AS WELL AS MONTEREY BAY SHOULD SEE GRADUAL DISSIPATION OF LOW CLOUDS THROUGH THE MORNING WITH PRESSURE GRADIENT BECOMING MORE NORTHERLY. NAM SUGGESTS INCREASING NORTHERLY GRADIENT THROUGH FRIDAY FROM SFO TO ACV WITH INCREASING 850 MB TEMPERATURES. HIGHS THIS AFTERNOON SHOULD END UP A FEW DEGREES WARMER INLAND WITH NOT MUCH CHANGE NEAR THE COAST. CURRENT STATEMENTS STILL ON TRACK HIGHLIGHTING WARM INLAND TEMPERATURES THIS WEEKEND AND HEIGHTENED FIRE WEATHER CONCERNS. && ...TURNING HOT INLAND FRIDAY AND SATURDAY... .DISCUSSION...AS OF 3:48 AM PDT THURSDAY...MAIN FORECAST FOCUS WILL DEAL WITH HIGH TEMPERATURE FORECASTS THE NEXT SEVERAL DAYS. OVERALL IDEA WILL SHOW WARMING TREND STARTING TODAY AND CONTINUING AT LEAST THROUGH SATURDAY...AND POSSIBLY SUNDAY FOR THE INLAND VALLEYS. A FEW DAYS AGO THE MODELS WERE HINTING THAT THE THERMAL TROUGH MAY SHIFT TO THE COAST FRIDAY OR SATURDAY MORNING. LATEST MODELS SOLUTIONS AREN`T REALLY SHOWING THAT SO THE FLOW AT THE SURFACE LOOKS TO REMAIN ONSHORE THROUGH THIS EVENT. THEREFORE HOT WEATHER WILL BE CONFINED TO THE INLAND VALLEYS. THIS WOULD INCLUDE THOSE LOCATIONS EAST OF THE EAST BAY HILLS AS WELL AS THE NORTH BAY VALLEYS AND SANTA CLARA VALLEY. EVEN THOUGH ALL LOCATIONS WILL OBSERVE A NOTED WARMING TREND...THE PRESENCE OF WESTERLY WINDS THROUGH THE EVENT SHOULD KEEP ANY SERIOUS HEAT IN CHECK FOR LOCATIONS INSIDE SF BAY AS WELL AS AROUND THE MONTEREY BAY. SO IF ANYTHING WE SHOULD SET UP SOME WELL DEFINED MICRO-CLIMATES WITH SOME POTENTIALLY HUGE TEMPERATURE SPREADS ACROSS THE DISTRICT BY SATURDAY. SHOULD BE ABLE TO SEE TEMPERATURES RANGE FROM 60S AT THE BEACHES TO AROUND 105 FOR THE WARMEST INLAND SPOTS. OTHER ITEMS TO MONITOR WILL BE SOME LIGHT TO MODERATE NORTH WINDS IN THE HILLS LATER FRIDAY NIGHT INTO EARLY SATURDAY AND THEN AGAIN SATURDAY NIGHT. 850 MB TEMPS SHOULD STAY WELL ABOVE 20 CELSIUS SO SOME HILL LOCATIONS ABOVE 1500 FEET WILL LIKELY SEE OVERNIGHT LOWS AROUND 70 DEGREES WITH BREEZY NORTH WINDS AND POOR HUMIDITY RECOVERY WHICH WILL BECOME A FIRE WEATHER CONCERN. HOWEVER...SIMILAR TO THE HEAT IT WOULD APPEAR WE`LL STAY OUT OF ANY WARNING CRITERIA FOR FIRE WEATHER OR HEAT RELATED PRODUCTS AT THIS TIME. HAVE REFRESHED THE SPECIAL WEATHER STATEMENT TO KEEP THE MESSAGE GOING FOR OVERALL CHANGE IN THE WEATHER...TO HOTTER INLAND TEMPS. ECMWF SOLUTION PINCHES OFF A 500 MB CIRCULATION JUST OFF THE COAST BY SUNDAY. THIS WILL LIKELY INDUCE SOME SORT OF COASTAL COOLING TREND IN THE FORM OF MARINE CLOUDS OR A SOUTHERLY WIND REVERSAL. 850 MB TEMPS WILL STAY AROUND 22 CELSIUS THROUGH SUNDAY AFTERNOON SO ANY INLAND COOLING WILL BE MINOR AT BEST THROUGH THE WEEKEND. BY MONDAY HEIGHTS WILL DROP...ONSHORE FLOW WILL INCREASE AND 850 MB TEMPS WILL NUDGE DOWNWARD AS WELL WHICH SHOULD LEAD TO A MARKED INLAND COOLING TREND AS WELL. FORECAST FOR NEXT WEEKS SHOWS A WEAK CIRCULATION OFF THE COAST WHICH SHOULD KEEP A WELL DEFINED AND FAIRLY DEEP MARINE LAYER IN PLACE. ANY CONVECTION WILL LIKELY STAY OVER THE SIERRA EVEN THOUGH THE GFS WANTS TO SPIT SOME OUT CLOSER TO THE CENTER OF THE LOW. AS THE CALENDAR TURNS TO JUNE A FORECAST NEAR CLIMATOLOGICAL NORMS LOOKS PRETTY GOOD. && .AVIATION...AS OF 4:45 AM PDT THURSDAY...MAINLY VFR CONDITIONS OVER THE TERMINALS THROUGH THE FORECAST AS HIGH PRESSURE BEGINS TO BUILD OVER THE REGION. PATCHES OF STRATUS FORMED OVER THE MONTEREY BAY AND SAN MATEO COAST OVERNIGHT...AND ARE LIKELY TO EXPAND THROUGH SUNRISE...MAINLY IMPACTING THE MONTEREY BAY TERMINALS. OTHERWISE...MODERATE ONSHORE FLOW THIS AFTERNOON WITH PATCHY STRATUS AGAIN FRIDAY MORNING. VICINITY OF KSFO...VFR CONDITIONS THROUGH THE FORECAST. STRENGTHENING NORTHERLY GRADIENTS WILL LIKELY KEEP STRATUS OUT OF THE SF BAY TERMINALS. THERE IS A CHANCE THAT PATCHY STRATUS WILL IMPACT KOAK THROUGH 17Z. MODERATE WEST WINDS TO 25 KT THIS AFTERNOON THROUGH THE EARLY EVENING HOURS. KSFO BRIDGE APPROACH...OCCASIONAL PATCHES OF STRATUS MAY DRIFT OVER THE APPROACH THROUGH 17Z. LOW CONFIDENCE. MONTEREY BAY AREA TERMINALS...IFR CIGS THROUGH 17Z. LOW CONFIDENCE. MOST OF THE SHORT TERM MODELS INITIALIZED POORLY...WITH ONLY THE LOCAL WRF AND HRRR INDICATING STRATUS MAY DEVELOP OVERNIGHT. BOTH OF THESE MODELS ARE CONSISTENT IN THE FACT THAT STRATUS WILL DISSIPATE BY 17Z. OTHERWISE...MODERATE WESTERLY WINDS THIS AFTERNOON. && .CLIMATE DATA FOR JUNE 1ST... LOCATION FORECAST NORMAL RECORD TEMPERATURE SANTA ROSA 92 77 95 1919 SAN RAFAEL 88 73 101 1960 NAPA 91 79 105 1960 SAN FRANCISCO 73 65 90 1989 OAKLAND 80 70 87 1989 LIVERMORE 98 80 105 1938 SANTA CRUZ 85 73 93 1912 SALINAS AIR 78 69 85 1935 .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PT REYES 0-10 NM SCA...PIGEON PT TO PT PINOS 0-10 NM SCA...PT ARENA TO PIGEON PT 10-60 NM SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM GLW...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...SF BAY FROM 2 PM SCA...MRY BAY FROM 2 PM && $$ PUBLIC FORECAST: KBB AVIATION/MARINE: RILEY CLIMATE: HENDERSON/LARRY VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
453 AM PDT THU MAY 30 2013 ...TURNING HOT INLAND FRIDAY AND SATURDAY... .DISCUSSION...AS OF 3:48 AM PDT THURSDAY...MAIN FORECAST FOCUS WILL DEAL WITH HIGH TEMPERATURE FORECASTS THE NEXT SEVERAL DAYS. OVERALL IDEA WILL SHOW WARMING TREND STARTING TODAY AND CONTINUING AT LEAST THROUGH SATURDAY...AND POSSIBLY SUNDAY FOR THE INLAND VALLEYS. A FEW DAYS AGO THE MODELS WERE HINTING THAT THE THERMAL TROUGH MAY SHIFT TO THE COAST FRIDAY OR SATURDAY MORNING. LATEST MODELS SOLUTIONS AREN`T REALLY SHOWING THAT SO THE FLOW AT THE SURFACE LOOKS TO REMAIN ONSHORE THROUGH THIS EVENT. THEREFORE HOT WEATHER WILL BE CONFINED TO THE INLAND VALLEYS. THIS WOULD INCLUDE THOSE LOCATIONS EAST OF THE EAST BAY HILLS AS WELL AS THE NORTH BAY VALLEYS AND SANTA CLARA VALLEY. EVEN THOUGH ALL LOCATIONS WILL OBSERVE A NOTED WARMING TREND...THE PRESENCE OF WESTERLY WINDS THROUGH THE EVENT SHOULD KEEP ANY SERIOUS HEAT IN CHECK FOR LOCATIONS INSIDE SF BAY AS WELL AS AROUND THE MONTEREY BAY. SO IF ANYTHING WE SHOULD SET UP SOME WELL DEFINED MICRO-CLIMATES WITH SOME POTENTIALLY HUGE TEMPERATURE SPREADS ACROSS THE DISTRICT BY SATURDAY. SHOULD BE ABLE TO SEE TEMPERATURES RANGE FROM 60S AT THE BEACHES TO AROUND 105 FOR THE WARMEST INLAND SPOTS. OTHER ITEMS TO MONITOR WILL BE SOME LIGHT TO MODERATE NORTH WINDS IN THE HILLS LATER FRIDAY NIGHT INTO EARLY SATURDAY AND THEN AGAIN SATURDAY NIGHT. 850 MB TEMPS SHOULD STAY WELL ABOVE 20 CELSIUS SO SOME HILL LOCATIONS ABOVE 1500 FEET WILL LIKELY SEE OVERNIGHT LOWS AROUND 70 DEGREES WITH BREEZY NORTH WINDS AND POOR HUMIDITY RECOVERY WHICH WILL BECOME A FIRE WEATHER CONCERN. HOWEVER...SIMILAR TO THE HEAT IT WOULD APPEAR WE`LL STAY OUT OF ANY WARNING CRITERIA FOR FIRE WEATHER OR HEAT RELATED PRODUCTS AT THIS TIME. HAVE REFRESHED THE SPECIAL WEATHER STATEMENT TO KEEP THE MESSAGE GOING FOR OVERALL CHANGE IN THE WEATHER...TO HOTTER INLAND TEMPS. ECMWF SOLUTION PINCHES OFF A 500 MB CIRCULATION JUST OFF THE COAST BY SUNDAY. THIS WILL LIKELY INDUCE SOME SORT OF COASTAL COOLING TREND IN THE FORM OF MARINE CLOUDS OR A SOUTHERLY WIND REVERSAL. 850 MB TEMPS WILL STAY AROUND 22 CELSIUS THROUGH SUNDAY AFTERNOON SO ANY INLAND COOLING WILL BE MINOR AT BEST THROUGH THE WEEKEND. BY MONDAY HEIGHTS WILL DROP...ONSHORE FLOW WILL INCREASE AND 850 MB TEMPS WILL NUDGE DOWNWARD AS WELL WHICH SHOULD LEAD TO A MARKED INLAND COOLING TREND AS WELL. FORECAST FOR NEXT WEEKS SHOWS A WEAK CIRCULATION OFF THE COAST WHICH SHOULD KEEP A WELL DEFINED AND FAIRLY DEEP MARINE LAYER IN PLACE. ANY CONVECTION WILL LIKELY STAY OVER THE SIERRA EVEN THOUGH THE GFS WANTS TO SPIT SOME OUT CLOSER TO THE CENTER OF THE LOW. AS THE CALENDAR TURNS TO JUNE A FORECAST NEAR CLIMATOLOGICAL NORMS LOOKS PRETTY GOOD. && .AVIATION...AS OF 4:45 AM PDT THURSDAY...MAINLY VFR CONDITIONS OVER THE TERMINALS THROUGH THE FORECAST AS HIGH PRESSURE BEGINS TO BUILD OVER THE REGION. PATCHES OF STRATUS FORMED OVER THE MONTEREY BAY AND SAN MATEO COAST OVERNIGHT...AND ARE LIKELY TO EXPAND THROUGH SUNRISE...MAINLY IMPACTING THE MONTEREY BAY TERMINALS. OTHERWISE...MODERATE ONSHORE FLOW THIS AFTERNOON WITH PATCHY STRATUS AGAIN FRIDAY MORNING. VICINITY OF KSFO...VFR CONDITIONS THROUGH THE FORECAST. STRENGTHENING NORTHERLY GRADIENTS WILL LIKELY KEEP STRATUS OUT OF THE SF BAY TERMINALS. THERE IS A CHANCE THAT PATCHY STRATUS WILL IMPACT KOAK THROUGH 17Z. MODERATE WEST WINDS TO 25 KT THIS AFTERNOON THROUGH THE EARLY EVENING HOURS. KSFO BRIDGE APPROACH...OCCASIONAL PATCHES OF STRATUS MAY DRIFT OVER THE APPROACH THROUGH 17Z. LOW CONFIDENCE. MONTEREY BAY AREA TERMINALS...IFR CIGS THROUGH 17Z. LOW CONFIDENCE. MOST OF THE SHORT TERM MODELS INITIALIZED POORLY...WITH ONLY THE LOCAL WRF AND HRRR INDICATING STRATUS MAY DEVELOP OVERNIGHT. BOTH OF THESE MODELS ARE CONSISTENT IN THE FACT THAT STRATUS WILL DISSIPATE BY 17Z. OTHERWISE...MODERATE WESTERLY WINDS THIS AFTERNOON. && .CLIMATE DATA FOR JUNE 1ST... LOCATION FORECAST NORMAL RECORD TEMPERATURE SANTA ROSA 92 77 95 1919 SAN RAFAEL 88 73 101 1960 NAPA 91 79 105 1960 SAN FRANCISCO 73 65 90 1989 OAKLAND 80 70 87 1989 LIVERMORE 98 80 105 1938 SANTA CRUZ 85 73 93 1912 SALINAS AIR 78 69 85 1935 .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PT REYES 0-10 NM SCA...PIGEON PT TO PT PINOS 0-10 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM SCA...PT ARENA TO PIGEON PT 10-60 NM SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...SF BAY FROM 2 PM SCA...MRY BAY FROM 2 PM && $$ PUBLIC FORECAST: RWW AVIATION/MARINE: RILEY CLIMATE: HENDERSON/LARRY VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1036 AM EDT THU MAY 30 2013 .UPDATE... THE FLOOD WATCH THAT WAS IN EFFECT FOR THE EASTERN HALF OF SOUTH FLORIDA HAS BEEN CANCELLED. WHILE THE 12Z SOUNDING HAD A PWAT NEAR TWO INCHES...THE OVERALL SYNOPTIC CONDITIONS ARE NOT COMPLETELY FAVORABLE FOR WIDESPREAD CONVECTION ACROSS THE EASTERN HALF OF SOUTH FLORIDA AND THE AREAL COVERAGE OF POTENTIALLY HEAVY RAINFALL IS EXPECTED TO BE LESS. HOWEVER...LOCALLY HEAVY RAINFALL IS STILL POSSIBLE ACROSS SOUTH FLORIDA TODAY BUT OVER ISOLATED AREAS. TWO SYNOPTIC FACTORS THAT HAVE REDUCED THE CHANCES OF CONVECTION OVER A MORE WIDESPREAD AREA INCLUDE THE POSITION OF THE UPPER LEVEL TROUGH AND THE MID LEVEL LAPSE RATE/TEMPERATURE. THE UPPER LEVEL TROUGH ACROSS THE SOUTHEASTERN U.S. IS ORIENTATED SUCH THAT A WEAK RIDGE HAS BUILT ACROSS THE REGION AND THE 12Z SOUNDING INDICATED 500 HPA TEMPERATURES THAT ARE REPRESENTATIVE OF CLIMATOLOGY FOR THIS DATE. PLUS THE LAPSE RATES ABOVE 500 HPA ARE WEAK. FOR THESE REASONS WIDESPREAD CONVECTION ACROSS THE EASTERN HALF OF SOUTH FLORIDA IS LESS LIKELY AND THE FLOOD WATCH HAS BEEN CANCELLED. HOWEVER...ABUNDANT LOW LEVEL MOISTURE CONTINUES ACROSS THE REGION AND SOME DRIER MID TO UPPER LEVEL IS PRESENT. FOR THE AFTERNOON AND EARLY EVENING...DAY TIME HEATING SHOULD RESULT IN CONVECTION WITH ISOLATED THUNDERSTORMS POSSIBLE AND A SLIGHT CHANCE OF SMALL HAIL. AND NEED TO RE-EMPHASIZE THAT LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IN ISOLATED AREAS. REGIONAL OBSERVATIONS ACROSS THE LOCAL ATLANTIC WATERS INDICATE STRONG WINDS IN THE 20 TO 24 KNOT RANGE POSSIBLE WITH A SMALL CRAFT ADVISORY CONTINUING ACROSS THE ATLANTIC WATERS...INCLUDING BISCAYNE BAY. A SMALL CRAFT ADVISORY FOR THE GULF WATERS CONTINUES TO BE IN EFFECT THROUGH 00Z THIS EVENING BUT LATEST GUIDANCE INDICATES THAT WINDS SHOULD SLOWLY SUBSIDE THROUGH THE DAY AND THAT ADVISORY MAY BE CANCELLED WITH THE AFTERNOON ISSUANCE OF THE COASTAL WATERS FORECAST. 60 && .PREV DISCUSSION... /ISSUED 700 AM EDT THU MAY 30 2013/ AVIATION... BERMUDA HIGH CONTINUES TO BRING STRONG EASTERLY FLOW AND RAIN SHOWERS TO SOUTH FLORIDA THROUGH THE TAF PERIOD. THE RAIN MAY BE HEAVY AT TIMES, REDUCING FLIGHT CATEGORIES TO MVFR AND IFR FOR SHORT PERIODS OF TIME. HOWEVER, WITH SUCH GREAT UNCERTAINTY AS TO WHEN AND WHERE THIS WILL OCCUR, HAVE NOT REFLECTED THE REDUCTIONS IN THE TAFS AT THIS TIME. WINDS WILL BE GUSTY ONCE AGAIN TODAY, WITH SOME WEAKENING SOME TONIGHT. PREV DISCUSSION... /ISSUED 238 AM EDT THU MAY 30 2013/ SHORT TERM (TODAY THROUGH SATURDAY)... THE GLOBAL MODELS CONTINUE TO STRUGGLE WITH THE OVERALL SURFACE SYNOPTIC PATTERN IN THIS PERIOD BUT ARE IN AGREEMENT THAT THE MID LEVEL PRESSURE PATTERN WILL REMAIN QUITE WEEK ACROSS SOUTH FLORIDA. THE GFS, ECMWF AND NAM ALL SHOW A WEAK 500 MB TROUGH DEVELOPING EAST OF THE PENINSULA ON FRIDAY AND SATURDAY DRIFTING IT TO THE NORTHEAST. THIS COULD ALLOW FOR SOME SLIGHT DRYING ALOFT AS DRIER AIR MOVES SOUTHWARD ON THE WEST SIDE OF THE TROUGH. THIS IS REFLECTED IN THE LATEST POP GUIDANCE FROM BOTH THE MET AND MAV WHICH SHOW A TREND WITH LOWER NUMBERS AFTER TODAY. THE NAM AND GFS HAVE COME MORE IN LINE AT THE SURFACE IN DEVELOPING A WEAK INVERTED TROUGH OVER THE FLORIDA STRAITS ON FRIDAY AND DRIFTING IT TO THE NORTH ON SATURDAY WHICH LESSENS THE LOW LEVEL SOUTHEAST WIND FLOW SIGNIFICANTLY. THE ECMWF DOES NOT SHOW THIS FEATURE MAINTAINING AN ONSHORE FLOW ALONG THE SOUTHEAST COAST ALTHOUGH IN A WEAKENED STATE AS IT SHOWS THE RIDGE TO THE NORTH WEAKENING. THE NAM HAS INITIALIZED THE BEST COMPARING IT TO CURRENT OBSERVATIONS FROM THE C-MAN STATIONS BUT THE QUESTION WILL THE WEAK TROUGH DEVELOP AS FORECAST FROM THE NAM AND GFS. EVEN THOUGH THE NAM AND GFS HAVE BEEN CONSISTENT IN FORECASTING THIS TROUGH, THEY HAVE BEEN VERY INCONSISTENT IN ITS TIMING. THEREFORE, WILL LEAN TOWARDS THE NAM EARLY IN THE PERIOD BUT THEN GO MORE WITH THE ECMWF FOR FRIDAY NIGHT AND SATURDAY. THE OTHER FACTOR IN THE SHORT TERM IS THE AMOUNT OF RAINFALL THAT IS POSSIBLE. MOST OF THE RAIN THE PAST FEW DAYS HAS BEEN CONCENTRATED OVER THE EASTERN HALF OF THE SOUTHERN PENINSULA WITH VERY SATURATED GROUNDS FROM PERSISTENT RAIN PERIODS SINCE APRIL. GIVEN THE ONGOING ONSHORE FLOW OF MOIST AND UNSTABLE AIR AND SCATTERED SHOWERS, THE FLOOD WATCH WILL CONTINUE THROUGH 12Z FRIDAY. THE LATEST RUN OF THE HRRR WHICH TYPICALLY DOES QUITE WELL DOES NOT SHOW MUCH ACTIVITY THROUGH EARLY THURSDAY. HOWEVER, WITH VERY LITTLE CHANGE IN THIS PATTERN AT LEAST THROUGH THURSDAY NIGHT THE SHOWER ACTIVITY COULD DEVELOP AT ANY TIME AND MOVE ONSHORE WITHIN THE FLOOD WATCH BOX. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... BOTH THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING A MID LEVEL TROUGH DEEPENING ACROSS THE EASTERN U.S. MAINTAINING A RIDGE TO THE WEST AND A WEAK PRESSURE PATTERN ACROSS SOUTH FLORIDA. AT THE SURFACE, BOTH MODELS COME MORE IN LINE WITH A LIGHTER SOUTHEAST FLOW AS THE RIDGE WEAKENS AND SHIFTS TO THE EAST AS A WEAK COLD FRONT MOVES INTO THE SOUTHEAST STATES. HOWEVER, THE GFS THEN DEVELOPS A STRONGER SURFACE TROUGH OVER THE GULF STATES LATE IN THE PERIOD AND VEERS THE WIND ACROSS SOUTH FLORIDA TO THE SOUTHWEST. BEING THIS LATE IN THE FORECAST, WILL NOT JUMP ON THAT AND WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH THE ENTIRE EXTENDED PERIOD. MARINE... ROUGH MARINE CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY FRIDAY. MODEL GUIDANCE HINTS AT SOME WEAKENING IN THE GRADIENT FLOW LATE FRIDAY INTO THE WEEKEND WITH CALMER WIND AND SEAS. JUST HOW MUCH WEAKENING DEPENDS ON THE RAPIDNESS OF THE SLACKENING GRADIENT WITH TIME. FOR NOW, HAVE KEPT A SOUTHEAST FLOW WITH SUBSIDING SPEEDS AS HIGH PRESSURE RETREATS TO THE EAST. FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 84 77 86 76 / 60 30 50 40 FORT LAUDERDALE 83 76 85 77 / 60 40 50 40 MIAMI 83 75 87 76 / 60 40 50 40 NAPLES 89 72 89 74 / 60 30 40 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...RIP CURRENT RISK THROUGH FRIDAY AFTERNOON FOR COASTAL BROWARD- COASTAL MIAMI DADE-COASTAL PALM BEACH. AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM. GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM- COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING FROM 20 TO 60 NM. && $$ DISCUSSION/MARINE/FIRE...60/BD AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
700 AM EDT THU MAY 30 2013 .AVIATION... BERMUDA HIGH CONTINUES TO BRING STRONG EASTERLY FLOW AND RAIN SHOWERS TO SOUTH FLORIDA THROUGH THE TAF PERIOD. THE RAIN MAY BE HEAVY AT TIMES, REDUCING FLIGHT CATEGORIES TO MVFR AND IFR FOR SHORT PERIODS OF TIME. HOWEVER, WITH SUCH GREAT UNCERTAINTY AS TO WHEN AND WHERE THIS WILL OCCUR, HAVE NOT REFLECTED THE REDUCTIONS IN THE TAFS AT THIS TIME. WINDS WILL BE GUSTY ONCE AGAIN TODAY, WITH SOME WEAKENING SOME TONIGHT. && .PREV DISCUSSION... /ISSUED 238 AM EDT THU MAY 30 2013/ SHORT TERM (TODAY THROUGH SATURDAY)... THE GLOBAL MODELS CONTINUE TO STRUGGLE WITH THE OVERALL SURFACE SYNOPTIC PATTERN IN THIS PERIOD BUT ARE IN AGREEMENT THAT THE MID LEVEL PRESSURE PATTERN WILL REMAIN QUITE WEEK ACROSS SOUTH FLORIDA. THE GFS, ECMWF AND NAM ALL SHOW A WEAK 500 MB TROUGH DEVELOPING EAST OF THE PENINSULA ON FRIDAY AND SATURDAY DRIFTING IT TO THE NORTHEAST. THIS COULD ALLOW FOR SOME SLIGHT DRYING ALOFT AS DRIER AIR MOVES SOUTHWARD ON THE WEST SIDE OF THE TROUGH. THIS IS REFLECTED IN THE LATEST POP GUIDANCE FROM BOTH THE MET AND MAV WHICH SHOW A TREND WITH LOWER NUMBERS AFTER TODAY. THE NAM AND GFS HAVE COME MORE IN LINE AT THE SURFACE IN DEVELOPING A WEAK INVERTED TROUGH OVER THE FLORIDA STRAITS ON FRIDAY AND DRIFTING IT TO THE NORTH ON SATURDAY WHICH LESSENS THE LOW LEVEL SOUTHEAST WIND FLOW SIGNIFICANTLY. THE ECMWF DOES NOT SHOW THIS FEATURE MAINTAINING AN ONSHORE FLOW ALONG THE SOUTHEAST COAST ALTHOUGH IN A WEAKENED STATE AS IT SHOWS THE RIDGE TO THE NORTH WEAKENING. THE NAM HAS INITIALIZED THE BEST COMPARING IT TO CURRENT OBSERVATIONS FROM THE C-MAN STATIONS BUT THE QUESTION WILL THE WEAK TROUGH DEVELOP AS FORECAST FROM THE NAM AND GFS. EVEN THOUGH THE NAM AND GFS HAVE BEEN CONSISTENT IN FORECASTING THIS TROUGH, THEY HAVE BEEN VERY INCONSISTENT IN ITS TIMING. THEREFORE, WILL LEAN TOWARDS THE NAM EARLY IN THE PERIOD BUT THEN GO MORE WITH THE ECMWF FOR FRIDAY NIGHT AND SATURDAY. THE OTHER FACTOR IN THE SHORT TERM IS THE AMOUNT OF RAINFALL THAT IS POSSIBLE. MOST OF THE RAIN THE PAST FEW DAYS HAS BEEN CONCENTRATED OVER THE EASTERN HALF OF THE SOUTHERN PENINSULA WITH VERY SATURATED GROUNDS FROM PERSISTENT RAIN PERIODS SINCE APRIL. GIVEN THE ONGOING ONSHORE FLOW OF MOIST AND UNSTABLE AIR AND SCATTERED SHOWERS, THE FLOOD WATCH WILL CONTINUE THROUGH 12Z FRIDAY. THE LATEST RUN OF THE HRRR WHICH TYPICALLY DOES QUITE WELL DOES NOT SHOW MUCH ACTIVITY THROUGH EARLY THURSDAY. HOWEVER, WITH VERY LITTLE CHANGE IN THIS PATTERN AT LEAST THROUGH THURSDAY NIGHT THE SHOWER ACTIVITY COULD DEVELOP AT ANY TIME AND MOVE ONSHORE WITHIN THE FLOOD WATCH BOX. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... BOTH THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING A MID LEVEL TROUGH DEEPENING ACROSS THE EASTERN U.S. MAINTAINING A RIDGE TO THE WEST AND A WEAK PRESSURE PATTERN ACROSS SOUTH FLORIDA. AT THE SURFACE, BOTH MODELS COME MORE IN LINE WITH A LIGHTER SOUTHEAST FLOW AS THE RIDGE WEAKENS AND SHIFTS TO THE EAST AS A WEAK COLD FRONT MOVES INTO THE SOUTHEAST STATES. HOWEVER, THE GFS THEN DEVELOPS A STRONGER SURFACE TROUGH OVER THE GULF STATES LATE IN THE PERIOD AND VEERS THE WIND ACROSS SOUTH FLORIDA TO THE SOUTHWEST. BEING THIS LATE IN THE FORECAST, WILL NOT JUMP ON THAT AND WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH THE ENTIRE EXTENDED PERIOD. MARINE... ROUGH MARINE CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY FRIDAY. MODEL GUIDANCE HINTS AT SOME WEAKENING IN THE GRADIENT FLOW LATE FRIDAY INTO THE WEEKEND WITH CALMER WIND AND SEAS. JUST HOW MUCH WEAKENING DEPENDS ON THE RAPIDNESS OF THE SLACKENING GRADIENT WITH TIME. FOR NOW, HAVE KEPT A SOUTHEAST FLOW WITH SUBSIDING SPEEDS AS HIGH PRESSURE RETREATS TO THE EAST. FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 84 77 86 76 / 60 30 50 40 FORT LAUDERDALE 83 76 85 77 / 70 40 50 40 MIAMI 83 75 87 76 / 70 40 50 40 NAPLES 89 72 89 74 / 60 30 40 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...FLOOD WATCH THROUGH FRIDAY MORNING FOR COASTAL BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND BROWARD-INLAND MIAMI DADE-INLAND PALM BEACH-METRO BROWARD- METRO MIAMI DADE-METRO PALM BEACH. RIP CURRENT RISK THROUGH FRIDAY AFTERNOON FOR COASTAL BROWARD- COASTAL MIAMI DADE-COASTAL PALM BEACH. AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE BAY-COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM. GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM- COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING FROM 20 TO 60 NM. && $$ DISCUSSION/MARINE/FIRE...30/KOB AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS POCATELLO ID
922 AM MDT THU MAY 30 2013 .UPDATE...NO UPDATES PLANNED FOR TODAY. ELONGATED UPPER TROUGH LAYING ACROSS THE AREA TODAY. WEAK SHORTWAVE IN PLACE OVER SOUTHERN IDAHO AND WEAK CONVECTION STILL ONGOING IN PORTIONS OF EASTERN HIGHLANDS PER RADAR IMAGERY. EASTERN IDAHO WEAKLY DESTABILIZED THIS AFTERNOON WITH 0 TO -2 LIFTEDS MAINLY NORTH OF KSUN-KPIH LINE. HRRR CONCURS WITH WEAK CONVECTION NORTH OF THIS LINE BUT ALSO STRETCHING SLIGHTLY SOUTH THROUGH THE EASTERN HIGHLANDS TO THE BEAR LAKE AREA...CLOSE TO SECONDARY AREA OF INSTABILITY OVER NORTHERN UTAH. REST OF THE FORECAST AREA LARGELY DRY AND STABLE. ONLY OTHER CONCERN WILL BE WINDS ACROSS THE SNAKE PLAIN. GUIDANCE CONTINUES TO INDICATE ADVISORY LEVEL WINDS THIS AFTERNOON AT KPIH SO WILL CONTINUE WIND ADVISORY FOR THE ENTIRE ZONE. EVEN IF WINDS ARE MARGINAL FOR THIS ADVISORY...LAKE WIND ADVISORY IS CERTAIN SO WILL LEAVE HEADLINE IN PLACE REGARDLESS. DMH && .PREV DISCUSSION... /ISSUED 315 AM MDT THU MAY 30 2013/ DISCUSSION...UPPER LOW IS SITTING OFF IN THE EAST PACIFIC JUST WEST OF VANCOUVER ISLAND. WV IMAGERY SHOWS A COUPLE OF WEAK IMPULSES OF ENERGY ROTATING OUT OF THE LOW. MODELS PROJECT LITTLE SENSIBLE WEATHER ASSOCIATED WITH THESE IMPULSES...AND WEATHER SHOULD BE RELATIVELY CLEAR ACROSS THE AREA TODAY. AS A RESULT...LOW LEVEL LAPSE RATES WILL STEEPEN ALLOWING SOME OF THE STRONGER WINDS TO MIX TO THE SURFACE THIS AFTERNOON. MOS GUIDANCE IS INDICATING STRONGER WINDS THAN YESTERDAY AND WE WILL LIKELY SEE ADVISORY LEVEL WIND SPEEDS THIS AFTERNOON ACROSS THE LOWER SNAKE RIVER PLAIN. DRY WEATHER SHOULD CONTINUE THROUGH SATURDAY AS UPPER RIDGING MOVES ACROSS THE AREA. ON SUNDAY...MODELS DEPICT AN AMPLIFYING UPPER TROUGH DEVELOPING OVER THE PACIFIC NORTHWEST...BUT CONTINUE TO PUSH MOST OF THE MOISTURE OVER NORTHERN IDAHO AND WESTERN MONTANA. THEREFORE WE SHOULD SEE LITTLE IN THE WAY OF POPS EARLY NEXT WEEK. THE 00Z GFS/ECMWF DROPS AN UPPER TROUGH OVER THE UPPER SNAKE HIGHLANDS...WHICH MAY BE THE ONLY AREA OF CONCERN IN THE EXTENDED PERIODS AS FAR AS POPS ARE CONCERNED. HINSBERGER AVIATION...ISOLATED THUNDERSTORMS EXPECTED OVER THE CENTRAL MOUNTAINS NORTH OF KSUN THIS AFTERNOON AND THE EASTERN HIGHLANDS AS WELL. TAF SITES SHOULD NOT BE AFFECTED TODAY BY THESE SHOWERS. MAIN CONCERN WILL BE STRONG SURFACE WINDS IN THE SNAKE PLAIN THIS AFTERNOON. STRONGEST WINDS WILL BE IN THE VICINITY OF KPIH WHERE A WIND ADVISORY HAS BEEN ISSUED FOR SOUTHWEST WINDS OF 25 TO 35 MPH BETWEEN 20Z AND 03Z THIS EVENING. RS/EP FIRE WEATHER...THE STORM TRACK HAS SHIFTED FURTHER NORTH TODAY. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER THE MOUNTAINS MAINLY NORTH OF A STANLEY TO DRIGGS LINE THIS AFTERNOON. STRONG GUSTY WINDS WILL REDEVELOP AGAIN THIS AFTERNOON IN THE SNAKE PLAIN...STRONGEST WINDS WILL BE LOCATED IN THE SOUTHERN HALF OF THE PLAIN FROM BURLEY TO BLACKFOOT. WEST TO SOUTHWEST WINDS OF 25 TO 35 MPH ARE EXPECTED FROM 1400 TO 2100 HOURS. ON FRIDAY...ISOLATED SHOWERS WILL BE LIMITED TO AREAS FROM LEADORE TO ISLAND PARK AND DRIGGS. RELATIVE HUMIDITY WILL LOWER TO AROUND 20 PERCENT AROUND ARCO FRIDAY AND TREND DOWNWARD TO THE UPPER TEENS BY SATURDAY AFTERNOON. RS/EP && .PIH WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 9 PM MDT THIS EVENING IDZ021. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1030 AM CDT THU MAY 30 2013 .DISCUSSION... ISSUED 1030 AM CDT THU MAY 30 2013 MORNING SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED ALONG THE EAST COAST AND LOW PRESSURE CENTERED OVER SOUTH DAKOTA. THE PRESSURE GRADIENT BETWEEN THESE TWO FEATURES IS CREATING STRONG/GUSTY SOUTHERLY WINDS ACROSS CENTRAL ILLINOIS...WITH THE 15Z/10AM OBS INDICATING GUSTS ALREADY EXCEEDING 30 MPH IN A FEW LOCATIONS. RADAR MOSAIC HAS BEEN FAIRLY QUIET SO FAR...WITH ONLY A FEW ISOLATED SHOWERS ACROSS EAST-CENTRAL ILLINOIS EARLIER THIS MORNING. DESPITE RATHER BULLISH PRECIP DEVELOPMENT IN THE WARM SECTOR AS ADVERTISED BY THE 12Z NAM...THINK ONLY ISOLATED SHOWERS/THUNDER WILL OCCUR ACROSS THE AREA THROUGH EARLY AFTERNOON. AS ATMOSPHERE DESTABILIZES...SCATTERED SHOWERS/STORMS WILL DEVELOP BY MID TO LATE AFTERNOON. LATEST HRRR SUGGESTS THE MOST WIDESPREAD CONVECTION WILL REMAIN WEST OF THE MISSISSIPPI RIVER UNTIL THIS EVENING WHEN STORMS TRACK INTO AT LEAST THE WESTERN HALF OF THE KILX CWA. HAVE UPDATED FORECAST TO LOWER POPS THIS MORNING...FEATURING ONLY ISOLATED SHOWERS THROUGH EARLY AFTERNOON. WILL GO WITH SCATTERED WORDING THIS AFTERNOON...THEN WILL HIT POPS HARD TONIGHT WHEN BETTER FORCING APPROACHES FROM THE WEST. ZONE UPDATE HAS ALREADY BEEN ISSUED. BARNES && .AVIATION... ISSUED 627 AM CDT THU MAY 30 2013 A STRONG LOW LEVEL JET AND AMPLY MOISTURE IN THE LOWER TROPOSPHERE WILL FUEL SHOWERS AND STORMS TODAY AND TONIGHT. THE TIMING OF THE STORMS IS STILL IN QUESTION...BUT HIGHER CHANCES APPEAR TO BE LATER THIS AFTERNOON AND THIS EVENING. WILL CONTINUE WITH TEMPO GROUPS FOR MVFR VIS AND CIG DURING THAT TIME. A FEW STORMS MAY BUBBLE UP IN THE WEAKLY CAPPED AIRMASS ALREADY BY 17Z FOR PIA AND SPI. RADAR AND SATELLITE LOOPS SHOW CONVECTIVE ELEMENTS ALREADY APPROACHING SOUTHWESTERN IL FROM MISSOURI...ASSOCIATED WITH A MESOSCALE VORTEX THAT WILL CLIP WESTERN IL THIS MORNING. THE REMNANTS OF THOSE EARLY MORNING STORMS COULD AFFECT PIA AND SPI LATER THIS MORNING. OTHERWISE...A STRONGER LINE OF STORMS IS FORECAST TO DEVELOP IN MISSOURI LATER THIS AFTERNOON AND MOVE INTO CENTRAL IL. SOME MODELS TIME THE STORMS STARTING IN THE EVENING...BUT WITH BOUNDARIES STILL IN THE AREA...WE MAY SEE SPORADIC STORMS ERUPT THIS AFTERNOON EVEN AHEAD OF THAT SYSTEM. MVFR OR IFR CONDITIONS ARE POSSIBLE DURING THE STRONGER STORMS...BUT THE TIMING OF IFR IS TOO VAGUE AT THIS POINT...SO WE DID NOT GO THAT LOW WITH THIS SET OF TAFS. WINDS WILL INCREASE QUICKLY THIS MORNING AS 55KT WINDS ARE NOT FAR OFF OF THE SURFACE. SOUTHERLY GUSTS TODAY MAY REACH OVER 30KT AT TIMES. IT WILL REMAIN BREEZY EVEN AFTER SUNSET THIS EVENING...WITH SUSTAINED WINDS IN THE 14-17KT RANGE THROUGH AT LEAST 06Z. SHIMON && .HYDROLOGY... ISSUED 316 AM CDT THU MAY 30 2013 FLASH FLOOD GUIDANCE REMAINS LOW /LESS THAN 1.5 IN/HR/ FOR AREAS WEST OF I-55 WHICH RECEIVED HEAVIER RAINS IN RECENT DAYS. THE POTENTIAL EXISTS FOR SEVERAL ROUNDS OF CONVECTION TO IMPACT THESE AREAS AGAIN LATER TODAY AND ESPECIALLY FRIDAY...INTO SATURDAY UNTIL THE COLD FRONT PASSES. CURRENT FORECASTS SHOW 2 TO 4 INCHES OF RAIN...WITH HIGHER AMOUNTS POSSIBLE IF TRAINING OF STORMS OCCURS. THUS WILL HAVE A FLASH FLOOD WATCH I-55 AND WEST IN EFFECT THIS AFTERNOON THROUGH SATURDAY AFTERNOON. MUCH OF THE ADDITIONAL RAIN WILL RUN OFF INTO CREEKS...STREAMS...AND RIVERS. THIS WILL CAUSE ADDITIONAL RISES ON RIVERS THAT ARE ALREADY IN FLOOD...INCLUDING THE SPOON AND ILLINOIS. PORTIONS OF THE MACKINAW AND SANGAMON RIVERS WILL ALSO BE PRONE TO FLOODING IF THE HEAVIER RAINS DO MATERIALIZE. 25 && .PREV DISCUSSION... ISSUED 316 AM CDT THU MAY 30 2013 SHORT TERM...TODAY THROUGH SATURDAY 07Z SURFACE MAP SHOWED DOUBLE-BARREL LOW PRESSURE OVER THE PLAINS WITH ONE LOW CENTER IN CENTRAL SD AND A SOUTHERN LOW NEAR THE OK/TX PANHANDLE. TIGHTENING MSLP GRADIENT BETWEEN THIS AND SFC HIGH ALONG THE EAST COAST CAUSED 10-20 MPH S/SE WINDS OVERNIGHT...KEEPING DEWPOINTS UP IN THE MID 60S AND EARLY MORNING TEMPS IN THE UPPER 60S TO LOWER 70S. NEGATIVELY TILTED MID LEVEL TROF WAS LIFTING INTO THE WESTERN HIGH PLAINS RESPONSIBLE FOR LARGE AREA OF CONVECTION FROM THE PLAINS INTO THE UPPER MIDWEST. WATER VAPOR IMAGERY INDICATED A WEAK WAVE AND MID LEVEL MOISTURE POOL TRACKING NORTH FROM THE LOWER MS VALLEY...ON THE BACK SIDE OF THE SUB-TROPICAL RIDGE CENTERED OFF THE EAST COAST. SHORT RANGE HI-RES MODELS DEVELOP CONVECTION WITH THIS FEATURE AS IT SHIFTS NE INTO THE LOWER OHIO VALLEY THIS MORNING...AND LATEST RADAR MOSAIC INDICATED A SHOWER IN EAST CENTRAL IL AND A FEW MORE IN SE MO. THUS MAY SEE A SLIGHTLY MORE FOCUSED AREA OF SCATTERED SHOWERS/STORMS EAST OF I-57 INTO MID MORNING. OTHERWISE DEEPER CONVECTION IS EXPECTED TO DEVELOP OVER MISSOURI AND IOWA THIS AFTERNOON ASSOCIATED WITH A SIGNIFICANT SHORTWAVE EJECTING OUT OF THE WESTERN TROF. CONVECTIVE MODELS SHOW THIS ENTERING THE WESTERN CWA LATER THIS AFTERNOON AND EVENING...IN A WEAKENING FASHION AS LESS INSTABILITY IS INDICATED EAST OF THE MS RIVER. MOIST PROFILES ALSO SUGGEST A LOWER SVR THREAT...HOWEVER WITH DECENT WIND FIELDS ALOFT WOULD NOT BE SURPRISED TO SEE SOME STRONG OR NEAR SVR STORMS. ASIDE FROM POSSIBLE CONVECTION...ANOTHER ISSUE WILL BRISK AND GUSTY SOUTH WINDS IN TIGHT GRADIENT. BUFKIT DATA SHOWS GUSTS OVER 30 KTS DURING PEAK HEATING BUT CLOUD COVER COULD TEMPER HIGHER GUSTS. FAIRLY STRONG MODEL SIGNALS THAT AN MCS WILL FORM OVER KS/MO TONIGHT AND LIFT NORTHEAST INTO THE CWA ON FRIDAY. THIS SHOULD BE MAINTAINED BY A VIGOROUS 40-60 KT LLJ AND COULD BRING ANOTHER ROUND OF HEAVY RAIN TO THE NW CWA INTO MIDDAY. THE EFFECTS OF THIS MCS WILL IMPACT CONVECTIVE DEVELOPMENT LATER IN THE DAY AND IF ATMOSPHERE CAN RECOVER THEN STRONG STORMS MAY REDEVELOP ALONG THE LINGERING OUTFLOW BOUNDARY. BETTER WIND FIELDS ALOFT ASSOCIATED WITH THE APPROACHING UPPER TROF WILL CONTRIBUTE TO HIGHER BULK SHEAR AND THE POTENTIAL FOR MORE ORGANIZED SEVERE WEATHER. AS THE UPPER TROF STEADILY SHIFTS EAST...IT WILL DRIVE A COLD FRONT INTO THE STATE ON SATURDAY. FRONTAL TIMING WILL BE CRITICAL FOR ANOTHER ROUND OF POSSIBLE SEVERE STORMS AND HEAVY RAIN...AND 00Z MODELS ARE A FEW HOURS QUICKER WITH THE FRONT THAT PREVIOUS RUNS. THIS WOULD FAVOR BEST CHANCE OF REDEVELOPMENT ALONG THE FRONT OR PRE-FRONTAL TROF FOR THE CENTRAL OR EASTERN CWA SATURDAY AFTERNOON INTO EVENING. WITH THE THREAT FOR HEAVY RAIN STARTING LATER THIS AFTERNOON ACROSS THE WEST...AND CONTINUING UNTIL THE COLD FRONTAL PASSAGE SATURDAY HAVE DECIDED TO GO WITH ANOTHER FLASH FLOOD WATCH ALONG/WEST OF I-55. THIS WILL BE IN EFFECT THIS AFTERNOON THROUGH SATURDAY AFTERNOON. SEE HYDROLOGY SECTION BELOW FOR MORE INFO ON HEAVY RAIN/FLOOD POTENTIAL. LONG TERM...SUNDAY THROUGH WEDNESDAY THE POST-FRONTAL AIRMASS WILL BRING A RETURN TO MUCH COOLER AND DRIER WEATHER FOR THE LAST HALF OF THE WEEKEND. A DEEP TROF IS FORECAST TO ROTATE SOUTH INTO THE NORTHERN GREAT LAKES BY LATE SUNDAY WITH A CHILLY...FOR EARLY SUMMER...-24C 500 MB AIRMASS. CANADIAN HIGH PRESSURE AT THE SURFACE WILL BUILD INTO THE GREAT LAKES BY EARLY NEXT WEEK...AND CONTINUE TO PROVIDE A COOL NORTHERLY FLOW TO CENTRAL IL. THUS TEMPERATURES ARE EXPECTED TO BE SEVERAL DEGREES BELOW NORMAL INTO TUESDAY. BY LATE TUESDAY AND WEDNESDAY...THE NEXT UPPER LEVEL WAVE PUSHING INTO THE PLAINS WILL DEVELOP LOW PRESSURE TO OUR WEST. WARM ADVECTION PRECIP WITH THIS FEATURE WILL SPREAD RAIN CHANCES EAST OF THE MS RIVER FOR MID- WEEK. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SATURDAY EVENING FOR ILZ027>031- 036>038-040>042-047>051. && $$
AREA FORECAST DISCUSSION
NWS JACKSON KY
1037 AM EDT THU MAY 30 2013 .UPDATE... ISSUED AT 1037 AM EDT THU MAY 30 2013 NDFD AND WEB SERVERS HAVE BEEN UPDATED FOR LATEST SATELLITE AND SURFACE OBSERVATIONAL TRENDS. ZFP UPDATE NOT NEEDED AT THIS TIME. THE 12Z HRRR POINTS TOWARDS ISOLATED SHOWERS BEING POSSIBLE OVER THE FAR WESTERN PART OF THE FORECAST AREA FOR A FEW HOURS THIS AFTERNOON...SIMILAR TO YESTERDAY. EXPECT PROBABILITY TO REMAIN BELOW 15 PERCENT AND WILL NOT ADD THIS TO FORECAST. THE 12Z NAM SUPPORTS A DRY FORECAST THIS AFTERNOON....WITH LOW PROBABILITY OF SHOWERS IN THE WESTERN PART OF THE AREA TONIGHT. THIS IS IN THE CURRENT FORECAST FOR TONIGHT AND WILL LEAVE AS IS FOR NOW. UPDATE ISSUED AT 750 AM EDT THU MAY 30 2013 UPDATED THE FORECAST MAINLY TO KEEP THE NEAR TERM GRIDS ON TRACK WITH THE CURRENT OBS AND TRENDS...INCLUDING SKY COVER. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 335 AM EDT THU MAY 30 2013 06Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE EAST OF KENTUCKY AND DEEP LOW PRESSURE WELL TO THE NORTHWEST. A SOUTHERN FLOW OF WARMTH AND MOISTURE CONTINUES THROUGH THE STATE BETWEEN THESE TWO KEY FEATURES. ON SATELLITE...SOME HIGH CLOUDS AND A SMALLER BATCH OF LOWER ONES ARE CROSSING EAST KENTUCKY EARLY THIS MORNING. THESE CLOUDS HAVE ONLY HAD A SMALL IMPACT ON THE RADIATIONAL COOLING THROUGH THE CWA THIS NIGHT WITH RIDGES STAYING UP IN THE UPPER 60S AND LOWER 70S WHILE THE MOST SHELTERED VALLEYS CONTINUE THEIR PLUNGE INTO THE UPPER AND MIDDLE 50S. ALSO SIMILAR TO LAST NIGHT...DEEPER LOCATIONS IN THE WESTERN PORTIONS OF THE CUMBERLAND VALLEY...WEST OF I-75...ARE STAYING A BIT MILDER WHEN COMPARED TO VALLEYS FURTHER EAST. AT THE SAME TIME...DEWPOINTS ARE IN THE LOWER 60S THROUGHOUT THE AREA. WITH THE VALLEY TEMPS FALLING TO NEAR THEIR DEWPOINTS...DO EXPECT SOME LIGHT FOG TO DEVELOP IN THE PREDAWN HOURS...BUT STILL BE MAINLY CONFINED TO THE LOCATIONS ALONG RIVERS AND OTHER BODIES OF WATER. THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN AFFECTING THE REGION THROUGH THE SHORT TERM. THEY ALL SHOW THE SOUTHEAST RIDGE STRONGLY INFLUENCING EAST KENTUCKY FOR AT LEAST ONE MORE DAY WHILE A LARGE AREA OF TROUGHING CONSOLIDATES OVER THE HIGH PLAINS. HEIGHTS WILL START TO FALL LOCALLY LATER TONIGHT AS THE BROAD TROUGH TO THE NORTHWEST PRESSES IN ON THE WESTERN FRINGES OF THE OHIO VALLEY. THIS PROCESS WILL BE ACCOMPANIED BY A LEADING BAND OF SHORTWAVE ENERGY CROSSING INTO THE REGION BY DAWN FRIDAY...JUST NORTH OF THE OHIO RIVER. THIS BAND WEAKENS DURING THE DAY FRIDAY AS IT ADVANCES EAST INTO THE RETREATING RIDGE. THE NAM12 AND GFS HAVE SIMILAR IDEAS WITH THIS FIRST BATCH OF ENERGY AND ITS EFFECT ON WEATHER SO HAVE GONE WITH A BLEND OF THESE TWO MODELS FOR WX SPECIFICS THROUGH FRIDAY. SENSIBLE WEATHER WILL SEE THE WARM AND INCREASINGLY MUGGY AIR MASS SET THE STAGE FOR MORE IN THE WAY OF CONVECTION TO CLOSE OUT THE WORK WEEK. HIGHER PW AIR CONTINUES TO BUILD OVER EAST KENTUCKY TODAY AND FRIDAY. STILL CANNOT RULE OUT SOME STRAY POP UP STORMS LATE THIS AFTERNOON...MAINLY JUST TO OUR WEST...BUT WITH CHANCES STILL TOO LOW TO MENTION IN THE ZONES OR REPRESENT IN THE WX GRIDS AT THIS TIME. THIS IS DESPITE LOW LIS AND MODERATELY HIGH CAPE...AS A TRIGGER WILL BE HARD TO COME BY UNTIL LATER. A BETTER CHANCE FOR CONVECTION WILL OCCUR LATER TONIGHT...AGAIN PRIMARILY OVER OUR WESTERN ZONES...AS THE APPROACHING MID LEVEL WAVE WILL HELP YO ACTIVATE THIS INCREASINGLY SOUPY AIR MASS. THIS DEVELOPMENT WILL KEEP A DECENT THREAT OF SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGHOUT THE DAY FRIDAY...WORKING WEST TO EAST WITH TIME. THE EXPECTED INCREASE IN CLOUD COVER AND CONVECTION WILL ALSO LIKELY SERVE TO CAP TEMPERATURES IN THE MID 80S ON FRIDAY...A TAD LOWER THAN TODAY. BEFORE THE MORE ORGANIZED AREA OF CONVECTION GETS GOING LATE TONIGHT...DO EXPECT ANOTHER SMALL TO MODERATE RIDGE AND VALLEY TEMPERATURE SPLIT TO DEVELOP BY LATE EVENING THOUGH MUCH OF THIS WILL BE WASHED OUT BY THE LOWER CLOUDS AND SCATTERED COVERAGE OF SHOWERS AND THUNDERSTORMS TOWARD DAWN FRIDAY. HAVE USED THE CONSSHORT FOR TD AND WINDS THROUGH THE FIRST 24 HOURS AS A STARTING POINT...PERSISTENCE FOR HIGHS TODAY AND A MODIFIED VERSION OF THIS NIGHT/S LOWS FOR TONIGHT. FOR FRIDAY...FAVORED THE CONSALL FOR HIGHS. DID USE A DIURNAL FROM OBS SCHEME FOR HOURLY T GRIDS WITH SOME ADJUSTMENTS LATE TONIGHT TO ACCOUNT FOR THE INCREASE IN CLOUDS AND SCATTERED CONVECTION. AS FOR POPS...KEPT THEM IN LINE WITH LOW MOS GUIDANCE TODAY BEFORE ENDING UP CLOSER TO THE HIGHER MET NUMBERS TONIGHT AND THE LOWER MAV ONES ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 300 AM EDT THU MAY 30 2013 GENERAL AGREEMENT AMONGST THE FORECAST MODELS ONCE AGAIN FOR THE EXTENDED PERIOD OF THE FORECAST. THE GFS AND ECMWF SOLUTIONS WERE PREFERRED FOR THIS RENDITION OF THE EXTENDED DUE TO THEIR SIMILARITIES. THE TIMING OF THE PASSAGE OF A COLD FRONT SATURDAY NIGHT INTO SUNDAY WAS CAPTURED WELL BY BOTH PREFERRED MODELS. THE MODELS BOTH HAVE DEVELOPED A SLUGGISH FRONTAL PROGRESSION WHERE THE FRONT GETS HUNG UP A BIT NORTH OF THE OHIO SATURDAY EVENING. IT APPEARS THAT THE RIDGE THAT WILL DOMINATE THE WEATHER TODAY AND TOMORROW WILL BE VERY SLOW TO WEAKEN AND MOVE OFF TO THE EAST. WITH THIS IN MIND...DECIDED TO MODIFY THE FORECAST TOWARD THE SLOWER FRONTAL PROGRESSION SEEN IN BOTH THE GFS AND ECMWF. ISOLATED SHOWERS AND STORMS WILL BE POSSIBLE...AS A WEAK IMPULSE PUSHES ACROSS THE OHIO VALLEY FRIDAY EVENING. ONCE THIS BIT OF ENERGY EXITS THE AREA FRIDAY NIGHT...THERE SHOULD ANOTHER LULL IN THE PRECIPITATION...AS HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA DURING THE DAY ON SATURDAY. ONCE THE RIDGE FINALLY BREAKS DOWN AND MOVES OFF TO THE EAST...A COLD FRONT WILL PUSH ACROSS THE OHIO AND TENNESSEE VALLEYS SATURDAY NIGHT THROUGH SUNDAY NIGHT. WIDESPREAD SHOWERS AND STORMS ARE LIKELY TO ERUPT ALONG AND JUST IN ADVANCE OF THIS BOUNDARY...AS MOIST AIR FROM THE GULF OF MEXICO POURS INTO THE AREA ON SOUTHWESTERLY AND SOUTHERLY WINDS. THE LATEST FORECAST SOUNDINGS WERE SHOWING MUCH BETTER INSTABILITY AND WIND SHEAR DURING THE DAY ON SUNDAY...PARTICULARLY DURING THE AFTERNOON AND EVENING HOURS. WITH CONDITIONS A BIT MORE JUICY AND ENERGETIC...THE POSSIBILITY FOR A FEW STRONG STORMS WILL EXIST ON SUNDAY...WITH STRONG WINDS AND HAIL POSSIBLE. THE SOUNDINGS ALSO ARE SHOWING THE POTENTIAL FOR LOCALLY HEAVY RAINFALL...SO THIS WILL PRESENT THE POSSIBILITY OF LOCALIZED HYDROLOGY ISSUES WITH THE STRONGER STORMS OR WHERE SHOWERS AND STORM MOVE REPEATEDLY ACROSS THE SAME AREAS. WITH THE MODELS BEING IN GOOD AGREEMENT...AND THE MODELS SHOWING FAVORABLE CONDITIONS FOR SHOWERS AND STORMS TO FORM...WENT VERY CLOSE TO THE MEXMOS POPS FOR SATURDAY NIGHT AND SUNDAY. THE PERIOD WILL BEGIN WITH WELL ABOVE NORMAL TEMPERATURES...AS SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONT BRINGS WARM MOIST AIR INTO THE AREA IN LARGE QUANTITIES. AFTER THE FRONT PASSES THROUGH THE AREA LATE SUNDAY NIGHT...A MUCH COOLER AIR MASS WILL FILTER INTO THE AREA...PAVING THE WAY FOR NORMAL TEMPERATURES MONDAY AND TUESDAY. HIGHS EACH DAY WILL TOP OUT IN THE MID 70S. TEMPERATURES ON SUNDAY WILL ALSO BE AROUND NORMAL DUE TO THE INFLUENCE OF PRECIPITATION AND CLOUD COVER. ANOTHER RIDGE OF HIGH PRESSURE WILL THEN SETTLE OVER THE REGION ON TUESDAY WEDNESDAY...BRINGING COOLER AND DRIER WEATHER TO EASTERN KENTUCKY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 755 AM EDT THU MAY 30 2013 VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE END OF THE PERIOD AT ALL THREE TAF SITES. SOME SCT CU IN THE 5 TO 7K FT RANGE ALONG WITH HIGH CLOUDS WILL LIKELY WORK THEIR WAY BACK IN ACROSS THE WESTERN TAF SITES DURING THE MORNING AS HIGHER 850MB MOISTURE ADVECTS IN ALONG WITH DIURNAL HEATING TAKING EFFECT. BY MIDDAY... EXPECT ENOUGH CLOUDS AROUND 5-7K FEET TO GO WITH BKN CIGS INTO EARLY EVENING ACROSS THE AREA BEFORE TEMPORARILY SCATTERING OUT. THE APPROACH OF A MID LEVEL SHORT WAVE LOOKS TO BE ENOUGH TO GENERATE A BATCH OF SHOWERS AND THUNDERSTORMS TOWARD DAWN...HAVE ADDED A VCTS FOR THIS TO ALL THE TAFS. WINDS THROUGH THE PERIOD WILL BE RATHER LIGHT WITH PEAK SPEEDS OCCURRING AROUND MID AFTERNOON AT NEAR 10 KTS FROM THE SOUTH. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
524 AM CDT THU MAY 30 2013 .UPDATE... 12Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 353 AM CDT THU MAY 30 2013 A VERY ACTIVE SHORT TERM IS IN STORE AS A POTENT UPPER WAVE WORKS ACROSS THE NATIONS MIDSECTION. H5 RAP ANALYSIS SHOWS A CLOSED LOW HAS DEVELOPED NEAR THE BLACK HILLS THIS MORNING...WITH A NEGATIVELY TITLED TROUGH EXTENDING FROM THERE DOWN TO NORTHEAST TEXAS. THE RADAR MOSAIC WEDNESDAY WAS CRAMMED FULL OF CONVECTION FROM HERE ALL THE WAY DOWN TO TEXAS...WHICH MEANS WITHIN THIS LARGE SCALE TROUGH THERE ARE NUMEROUS LEFT OVER WAVES/MCVS. ONE SUCH WAVE IS OVER SW IA THAT WILL SWING THROUGH HERE IN THE LATE MORNING. THE MAIN SYNOPTIC UPPER WAVE WILL BEGIN WORKING ACROSS MN THIS AFTERNOON AND EVENING. TO GO ALONG WITH ALL OF THE WAVES...A 50 KT LLJ IS CURRENTLY BLOWING ACROSS MN. THIS LLJ WILL SLOWLY DIMINISH THROUGH THE MORNING...BUT A MUCH STRONGER PUSH CURRENTLY OVER OK/KS WILL COME UP INTO SE MN/WRN WI THIS AFTERNOON/EVENING WITH THE PRIMARY SYNOPTIC WAVE. AT THE SFC...A 995 MB SFC LOW CAN BE FOUND NEAR PIERRE SOUTH DAKOTA...WITH A WARM FRONT SITTING ACROSS CENTRAL MN. DURING THE SHORT TERM...THIS LOW WILL BECOME OCCLUDED AND SLOWLY MEANDER NORTH INTO NODAK. THE WARM FRONT WILL CONTINUE TO MOVE NORTH TODAY...EVENTUALLY SETTLING ALONG THE INTERNATIONAL BORDER. BACK TO THE WEST...A COLD FRONT MOVING ACROSS SODAK TODAY WILL BE ENTERING WRN MN BY THE END OF THE PERIOD. FOR TODAY...EXPECT A BRIEF LULL IN ACTIVITY THIS MORNING AS WE WAIT FOR THE WAVE OVER SW IA TO GET HERE AROUND 15Z. FORECAST SOUNDINGS ACROSS THE ENTIRE CWA SHOW VERY LITTLE IF ANY CAPPING...SO EXPECT SHOWERS AND STORMS TO DEVELOP QUICKLY THIS MORNING ONCE A LITTLE DAYTIME HEATING KICKS IN. SINCE WE WILL NOT BE ABLE TO BUILD MUCH INSTABILITY THANKS TO DENSE CLOUD COVER AND THE FACT THAT ONCE A LITTLE DEVELOPS THE ATMO WILL QUICKLY CONSUME IT...THE SEVERE THREAT LOOKS FAIRLY LOW TODAY. FOR SEVERE WEATHER...WILL HAVE TO WATCH THAT SECOND LLJ WORKING UP IN THE AFTERNOON. BY 00Z THE RAP HAS 50 KT WINDS AT H85 UP INTO OUR WI CWA. LIKE YESTERDAY...THIS COULD LEAD TO THE THREAT FOR BOWING LINE SEGMENTS AND DAMAGING WINDS. AS FOR ANY HYDROLOGY ISSUES TODAY...THE ONLY AREA THAT WILL PROBABLY HAVE TO BE WATCHED IS THE EAU CLAIRE AREA. THEY SET A DAILY RAINFALL RECORD YESTERDAY AND WILL BE UNDER THE GUN FOR THE SECOND LLJ SURGE THIS AFTERNOON...WITH THE POTENTIAL FOR SOME TRAINING OF STORMS THIS AFTERNOON AND EVENING. TONIGHT...THE COLD FRONT WILL START ENTERING WRN MN WHILE THE LLJ WORKS INTO CENTRAL/ERN WI. THIS SHOULD MOVE THE HEAVY RAIN THREAT EAST OF THE MPX CWA TONIGHT. HOWEVER...HI-RES CAMS SHOW SCT RETURNS CONTINUING THROUGH THE NIGHT AHEAD OF THE FRONT...SO HAVE POPS SLOWLY RAMPING DOWN FROM LIKELIES TO START THE EVENING...DOWN TO 50% POPS OR LESS BY 12Z FRIDAY. FOR TEMPERATURES...GIVEN ALL OF THE CLOUD COVER...IT WILL NOT BE AN OVERLY WARM WARM SECTOR TODAY...WITH HIGHS LIKELY STAYING IN THE MID TO UPPER 70S...DESPITE H85 TEMPS BEING UP AROUND +15C. FOR TONIGHT...MIXED LAYER DEWPS ON THE NAM DROP INTO THE 40S BEHIND THE FRONT...SO LOWS IN THE WRN CWA COULD END UP BEING A FEW DEGREES COOLER THAN WHAT IS CURRENTLY INDICATED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 353 AM CDT THU MAY 30 2013 MODELS INDICATE RATHER STRONG TROUGH AXIS WORKING THROUGH THE AREA BY FRIDAY MORNING. THIS SHOULD WORK MUCH OF THE RAIN AND THUNDER TO THE NORTH AND EAST OF THE AREA LATE THURSDAY NIGHT. THIS SHOULD WORK A DRY SLOT NORTHEAST INTO SOUTHWEST PORTION OF THE CWA DURING FRIDAY MORNING. THE UPPER CIRCULATION THEN MOVES A FRONTAL BOUNDARY EAST ACROSS EASTERN HALF OF THE CWA FRIDAY AFTERNOON. THE DETERMINISTIC MODELS ARE INDICATING MODEST DESTABILIZATION ACROSS THE EASTERN HALF OF THE AREA...WITH ML MUCAPE INCREASING TO 1500/2000 J/KG. SHEAR INCREASES INTO THE AFTERNOON...ESPECIALLY INTO WESTERN WISCONSIN. THE ONLY INHIBITING FACTOR FOR CONVECTIVE INITIATION ALONG THE FRONT APPEARS TO BE RATHER WEAK SURFACE CONVERGENCE..WITH WINDS S-SW ALONG THE BOUNDARY. THE HIRES MODELS ARE SHOWING RATHER ROBUST CONVECTION DEVELOPING ALONG THE BOUNDARY AS IT MOVES INTO EASTERN MINNESOTA FRIDAY AFTERNOON. WILL HAVE TO MONITOR THIS SITUATION INTO FRIDAY...AS SEVERE WEATHER THREAT IS FORECAST TO BE LOW AT THIS TIME. FRONT EXITS TO THE EAST FRIDAY NIGHT TAKING THE HEAVY CONVECTIVE POTENTIAL WITH IT. THIS WILL LEAVE THE UPPER LOW OVER THE AREA THROUGH AT LEAST SATURDAY. SHOWERS LOOK TO BE A FAIR BET ESPECIALLY LATER IN THE DAY AS THE LOW MOVES EAST. WITH ABUNDANT CLOUD COVER...WILL BE LITTLE IN THE WAY OF HEATING...SO CONVECTIVE POTENTIAL IS LOW. CLEARING SHOULD MOVE INTO THE AREA LATER SATURDAY NIGHT...AND SUNDAY LOOKS LIKE THE BEST DAY OF THE WEEKEND...WITH SUNSHINE AND MILD TEMPERATURES. THE EXTENDED PORTION OF THE FORECAST STARTS OFF RATHER COOL...ESPECIALLY OVER THE EASTERN CWA MONDAY MORNING. THERE MAY EVEN BE A FROST POTENTIAL OVER A PORTION OF WEST CENTRAL WISCONSIN. THE NEXT WEATHER SYSTEM MOVES INTO THE AREA LATER MONDAY WITH SOME SHOWERS INTO THE WESTERN CWA. THE 00Z GFS AND ECMWF DIVERGE SOMEWHAT ON THE OVERALL EVOLUTION AND MOVEMENT OF THE NEXT LOW PRESSURE SYSTEM THAT MOVES ACROSS THE NORTHERN STATES THROUGH MUCH OF NEXT WEEK. IT DOES APPEAR THE THREAT OF MORE SHOWERS AND THUNDERSTORMS RETURNS BY MIDWEEK...WITH TEMPERATURES REMAINING BELOW NORMAL THROUGH THE PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 523 AM CDT THU MAY 30 2013 ALL SIGNS POINT TO ANOTHER ACTIVE DAY AS THE MPX AREAS SITS IN A MOIST...UNSTABLE...AND WEAKLY CAPPED ENVIRONMENT. THERE IS NO REAL FOCUSING MECHANISM FOR STORMS TODAY...INSTEAD...EXPECT CONVECTION TO QUICKLY DEVELOP ONCE WE GET A LITTLE INSTABILITY...AS THE HRRR SHOWS HAPPENING RAPIDLY AFTER 15Z. DID ADD SOME TEMPO GROUPS FOR THUNDER EARLY THIS AFTERNOON...BUT COULD CERTAINLY SEE A COUPLE ROUNDS OF STORMS THROUGH THE EVENING...ESPECIALLY FOR MSP AND WI TERMINALS. TONIGHT...A COLD FRONT WILL MOVE INTO WRN MN...THOUGH IT ONLY LOOKS TO GET THROUGH RWF BY 12Z. BEING EAST OF THE FRONT STILL TONIGHT...EXPECT A SIMILAR TREND IN SHRA/TSRA ACTIVITY AS TO WHAT WAS SEEN LAST NIGHT. FOR CIGS...BEING MAINLY SOUTH OF THE WARM FRONT...EXPECT SPORADIC IFR/MVFR CIGS TO QUICKLY LIFT THIS MORNING...WITH VFR CIGS REMAINING OUTSIDE OF TSRA. DEPENDING HOW MUCH RAIN IS SEEN IN WI...MAY SEE MVFR CIGS RETURN THERE TONIGHT...BUT NOT OVERLY CONFIDENT ON THAT HAPPENING AT THE MOMENT. KMSP...HIGH CONFIDENCE IN STORMS OCCURRING TODAY...BUT WITH NO DEFINITIVE FRONT COMING THROUGH...CONFIDENCE IS LOW ON EXACT TIMING...OR EVEN EXACT NUMBER OF STORMS MSP WILL SEE TODAY INTO TONIGHT. FOR NOW...INSERTED A TEMPO GROUP FROM 18Z TO 21Z PER CONVECTIVE COVERAGE ON THE HRRR. WITH THE FRONT NEVER GETTING THROUGH THE FIELD THIS PERIOD...MAY SEE PERIODS OF SHOWERS THROUGH THE NIGHT...THOUGH EXPECT SHRA/TSRA ACTIVITY TO DECREASE CONSIDERABLY AFTER SUNSET. BY 18Z FRIDAY OR SHORTLY AFTER...WILL HAVE TO START THINKING ABOUT THE NEXT POTENTIAL ROUND OF TSRA. /OUTLOOK FOR KMSP/ FRI...SCT MVFR CIGS. SHRA/TSRA LIKELY. WINDS SW 10-15 KTS. SAT...MVFR CIGS POSSIBLE. SHRA LIKELY. WINDS WNW 5-10 KTS. SUN...MVFR CIGS POSSIBLE EARLY. WINDS N 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...DWE AVIATION...MPG
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
1044 AM CDT THU MAY 30 2013 .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 1044 AM CDT THU MAY 30 2013 COMPLICATED FORECAST FOR THE REST OF THE DAY AS AREA OF SHOWERS/ THUNDERSTORMS ARE MOVING VERY SLOWLY EASTWARD LATE THIS MORNING. THIS IS AHEAD OF THE NEGATIVELY TILTED TROUGH CURRENTLY OVER THE CENTRAL PLAINS THAT THE RAP LIFTS INTO MO/IL THIS EVENING. LAST FEW RUNS OF THE HRRR SUPPORTS THAT THE WESTERN MO COMPLEX WILL MOVE NORTHEASTWARD INTO THE CWA BY LATE THIS AFTERNOON/EARLY THIS EVENING. IN ADDITION...SCATTERED THUNDERSTORMS HAVE RECENTLY DEVELOPED OVER SOUTH CENTRAL MO THAT ARE LIFTING NORTHEASTWARD. THESE TRENDS SUPPORT GOING FORECAST THAT PRECIPITATION CHANCES WILL INCREASE THROUGH THE AFTERNOON. MLCAPES ARE CURRENTLY 1000-1500 J/K AND SHOULD INCREASE IN THE WARM SECTOR AS TEMPERATURES CLIMB INTO THE LOWER-MID 80S. 0-6KM SHEAR WILL BE RELATIVELY WEAK WHICH FAVORS MULTICELL STORMS...THOUGH INCREASING INSTABILITY AND LARGE SCALE LIFT SUGGEST THAT THERE MAY BE A FEW SEVERE STORMS CAPABLE OF PRODUCING SOME LARGE HAIL AND DAMAGING WIND GUSTS THROUGH THIS EVENING. THE LOW LEVEL JET WILL REMAIN 40-50KTS TODAY...SO CANNOT RULE OUT A TORNADO OR TWO IN THE STRONGEST STORMS. LATEST RADAR IMAGERY HAS SHOWN THE TENDENCY FOR CELLS TO TRAIN...SO HEAVY RAINFALL DOES LOOK LIKE A REAL THREAT GIVEN PWATS AROUND 1.8 INCHES. BRITT .LONG TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 343 AM CDT THU MAY 30 2013 (TONIGHT THROUGH SATURDAY NIGHT) PCPN CHANCES INCREASE TONIGHT AS NEXT IN SERIES OF MCS/S DEVELOPS OVER WESTERN MO AND SLIDES EAST THROUGH FORECAST AREA...WITH BEST CHANCES OF HEAVY RAIN ALONG AND NORTH OF I-70. SINCE THIS AREA HAS HAD QUITE A BIT OF RAIN OVER THE PAST WEEK AND SOILS REMAIN SATURATED...HAVE ISSUED A FLASH FLOOD WATCH FROM 18Z TODAY THROUGH 12Z SATURDAY. LOWS TONIGHT TO REMAIN MILD...IN THE MID 60S TO LOW 70S. FOR FRIDAY...A LOT WILL DEPEND ON HOW SOON THIS AREA OF STORMS WEAKENS/EXITS FORECAST AREA...ON WHAT WILL DEVELOP FOR THE AFTERNOON AND EVENING HOURS. IF ATMOSPHERE GETS WORKED OVER...IT WILL TAKE A LOT FOR IT TO RECOVER. FOR NOW...WILL ERR ON THE SIDE OF CAUTION WITH STORMS REDEVELOPING BY THE AFTERNOON HOURS AS NEXT SHORTWAVE SLIDES THROUGH. WITH DECENT INSTABILITY...MID LEVEL LAPSE RATES AND STRENGTHENING LOW LEVEL JET...WILL SEE A CHANCE FOR SEVERE WEATHER ONCE AGAIN FRIDAY AFTERNOON AND OVERNIGHT. ANOTHER ROUND OF HEAVY RAIN IS POSSIBLE AS WELL...WHICH WILL EVENTUALLY SHIFT TO THE SOUTH WITH TIME. SO MAY NEED TO EXTEND FLASH FLOOD WATCH TO INCLUDE REST OF FORECAST AREA. MAIN COLD FRONT TO FINALLY MOVE THROUGH THE AREA DURING THE DAY ON SATURDAY WITH LAST IN A SERIES OF SHORTWAVES SLIDING THROUGH...SO PCPN TO TAPER OFF BY SATURDAY EVENING. (SUNDAY THROUGH NEXT WEDNESDAY) COOLER AND DRIER WEATHER IS IN STORE FOR THE LAST PART OF THE WEEKEND AND INTO EARLY NEXT WEEK. HIGHS WILL BE IN THE UPPER 60S TO MID 70S SUNDAY THROUGH TUESDAY. THEN NEXT WEATHER SYSTEM TO APPROACH THE REGION BY MID WEEK WITH NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS BEGINNING TUESDAY NIGHT. BYRD && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 641 AM CDT THU MAY 30 2013 COMPLEX FORECAST FOR THIS TAF PERIOD WITH POTENTIAL FOR PROLONGED PERIODS OF THUNDER. IN THE NEAR TERM THERE ARE TWO MAIN AREAS WITH POTENTIAL IMPACTS. THE FIRST IS A SMALL NEWD MOVING CLUSTER OF SHOWERS AND THUNDERSTORMS WHICH MAY IMPACT KUIN BETWEEN 1230-1400Z. THE OTHER LESS OBVIOUS IS AN AREA OF SHOWERS S/SW OF ST LOUIS...WHICH THE MODELS INTENSIFY IN THE 13-16Z TIME FRAME AND MOVE INTO THE ST LOUIS AREA. AFTER 16Z THE TRENDS IN SHOWERS AND THUNDERSTORMS ARE DIFFICULT TO PINPOINT. SOMEWHERE IN THE 19-21Z TIME FRAME SEVERAL LINES/CLUSTERS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP AND IMPACT KUIN AND KCOU THRU 01-02Z...WITH THIS ACTIVITY SPREADING INTO THE ST LOUIS AREA BETWEEN 23-01Z. THEN DURING THE OVERNIGHT HOURS ANOTHER CLUSTER OF THUNDERSTORMS IS EXPECTED TO DEVELOP IN ERN KS/WRN MO AND MOVE EWD AFFECTING KCOU AROUND 10Z AND ST LOUIS BETWEEN 12-16Z ON FRIDAY. GUSTY SOUTHERLY WINDS ARE EXPECTED TODAY INTO EARLY EVENING. SPECIFICS FOR KSTL... COMPLEX FORECAST FOR THIS TAF PERIOD WITH POTENTIAL FOR PROLONGED PERIODS OF THUNDER. AN AREA OF SHOWERS S/SW OF ST LOUIS IS FORECAST TO INTENSIFY IN THE 13-16Z TIME FRAME AND MOVE INTO THE ST LOUIS AREA. AFTER 16Z THE TRENDS IN SHOWERS AND THUNDERSTORMS ARE DIFFICULT TO PINPOINT. SOMEWHERE IN THE 23-01Z TIME FRAME SEVERAL LINES/CLUSTERS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP AND/OR MOVE INTO THE TERMINAL. THIS ACTIVITY COULD PERSIST UNTIL 05Z WITH A BREAK UNTIL ANOTHER CLUSTER OF STORMS IMPACTS KSTL BETWEEN 12-16Z ON FRIDAY. GUSTY SOUTHERLY WINDS ARE EXPECTED TODAY INTO EARLY EVENING. GLASS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-FRANKLIN MO-GASCONADE MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO. IL...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR ADAMS IL-BROWN IL- CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL- MONROE IL-PIKE IL-ST. CLAIR IL. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
536 AM MDT THU MAY 30 2013 .AVIATION... 12Z TAF CYCLE AREA TO REMAIN UNDER THE INFLUENCE OF A FAST WEST-NORTHWEST FLOW ALOFT THROUGH AT LEAST 12Z FRI. AXIS OF STRONG UPPER JET LOCATED JUST NORTH OF THE STATE BUT IN A FAVORABLE POSITION AND ORIENTATION TO GENERATE MOUNTAIN WAVES AND ASSOCIATED IMPACTS OVER THE NORTHERN MOUNTAINS AND ESPECIALLY THE SANGRE DE CRISTO AND IMMEDIATE EAST SLOPES. SFC WINDS GUSTS FREQUENTLY IN THE 30-35 KT RANGE EXPECTED FOR ALL TERMINAL SITES EXCEPT KROW WHERE SOMEWHAT LIGHTER WIND CONDITIONS EXPECTED AS COMPARED TO CENTRAL AND NORTHERN AREAS OF THE STATE. AREAS OF BLOWING DUST EXPECTED TO RESULT IN REDUCED VSBY TO 5SM OR LESS AT TIMES...ESPECIALLY LOWER ELEVATIONS CENTRAL AND EAST. SIGNIFICANT CLOUD COVER IS NOT EXPECTED ALTHOUGH BRIEF BKN120 SKY CONDITIONS MAY BE ENCOUNTERED ACROSS THE FAR NORTH. KJ && .PREV DISCUSSION...325 AM MDT THU MAY 30 2013... DRYLINE HAS SO FAR STAYED TO THE EAST OF NEW MEXICO THIS MORNING AND ALTHOUGH IT/S FAIRLY CLOSE TO HOBBS DON/T EXPECT IT TO GET MUCH FARTHER WEST IF AT ALL. IN THE NORTHEAST DEWPOINTS HAVE COME UP AS THE SFC LOW SHIFTED INTO THE TX/OK PANHANDLES BUT THIS INCREASE LIKELY WON/T LAST LONG WITH THE RUC FORECASTING A WEAK SFC LOW TO REDEVELOP OVER SE CO BY MIDDAY. MODELS ALSO SHOW CURRENT BATCH OF MID LEVEL MOISTURE EXITING BY MIDDAY. UPPER JET TO RETREAT NWD TODAY BUT WILL BE STRETCHED OVER FAR NRN NM AND COLORADO...COMBINED WITH THE SFC LOW PLACEMENT WILL HAVE LOW END WIND ADVY OVER SOME OF THE NORTH CENTRAL/NORTHEAST SOUTH TO CLINES CORNERS. DRY INTO FRIDAY NIGHT. ANOTHER WINDY DAY ON FRIDAY WITH CRITICAL FIRE WX CONDITIONS POSSIBLE. ANOTHER BATCH OF MID LEVEL MOISTURE PASSES OVERHEAD TONIGHT AND FRIDAY BUT ANYTHING MORE THAN A FEW SPRINKLES OUT OF IT...IF THAT...WOULD BE A SURPRISE. SURFACE FRONT PUSHES THROUGH FRIDAY NIGHT WITH THE BACK DOOR FRONT INTO THE EAST SATURDAY. LOW LEVEL MOISTURE APPEARS TO MOVE IN FROM THE SOUTH AND SOUTHEAST WITH INCREASING INSTAB SO WENT AHEAD AND SPREAD SOME SMALL POPS FROM THE EAST SLOPES OF THE SOUTH CENTRAL MOUNTAIN ACROSS CHAVES COUNTY AND NORTHEAST ALONG THE TX BORDER SATURDAY AFTERNOON ALTHOUGH FOR NOW BEST CONFIDENCE IS IN THE SOUTHEAST. ANOTHER BLOB OF MID LEVEL MOISTURE TO MIGRATE OVER THE SOUTHERN HALF OF THE STATE AND COULD NOT RULE OUT A FEW SPRINKLES UNDERNEATH IT...BUT LEFT MENTION OUT OF FCST FOR NOW. IN FACT THE ADJMET GUIDANCE DOES PAINT SOME LOW POPS OVER THE SOUTHWEST MTS. INCREASED POPS SOMEWHAT SUNDAY ESPECIALLY ALONG THE CENTRAL MT CHAIN. LEFT THE MENTION OF DRY CONVECTION FROM THE RGV WWD ALTHOUGH COULD BE A MIX WITH AT LEAST SOME MEAGER MEASURABLE PCPN DEPENDING IF THE SURGE IS AS STRONG AS DEPICTED SO FAR. HOWEVER...MONDAY STARTS TO DRY OUT AND TUESDAY EVEN MORE SO. REMOVED THE POPS IN THE EAST FOR TUESDAY NIGHT...AND PROBABLY SHOULD HAVE FOR TUESDAY AS WELL AS RIGHT NOW IT LOOKS DRY. ANOTHER BACKDOOR FRONT WEDNESDAY LOOKS TO PUSH INTO THE RGV WEDNESDAY NIGHT...SO POPS/WX GRIDS FOR MID TO LATE WEEK HAVE BEEN UPDATED. .FIRE WEATHER... ...WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS DUE TO STRONG WIND AND LOW HUMIDITY FOR MUCH OF NORTHERN AND CENTRAL NEW MEXICO THROUGH FRIDAY... ...DRY LIGHTNING THREAT INCREASING SUNDAY CENTRAL/WEST... MOVING INTO DAY 2 OF A PROTRACTED CRITICAL FIRE WEATHER PATTERN THAT WILL EXTEND THROUGH FRIDAY. THEREAFTER...FAR LESS WIND BUT GROWING CONFIDENCE IN A SUBSTANTIAL WESTERLY PUSH OF LOWER LEVEL MOISTURE THAT WILL RESULT IN A SIGNIFICANT DRY LIGHTNING THREAT FOR CENTRAL/WESTERN AREAS BY SUNDAY. SATURDAY LOOKS TO BE A CLASSIC TRANSITION DAY AS RICHER LOW LEVEL MOISTURE INITIALLY MAKES A RETURN TO THE EC/SE PLAINS AS SURFACE WINDS VEER TO SELY AND TAPS INTO A NOW SEMI-PERMANENT POOL OF GULFMEX MOISTURE. POTENTIAL FOR SOME DRIER STORMS ALONG THE EAST SLOPES OF THE CENTRAL/SC MOUNTAIN SATURDAY PM. HIGHER DEW POINT AIR ALSO CREEPING NORTHWARD ALONG THE RGV AND THAT COUPLED WITH A SUBTLE AND ALWAYS SNEAKY UPTICK IN MID-LEVEL MOISTURE AS THE UPPER RIDGE EXPANDS/BUILDS NORTHWARD COULD RESULT IN AT LEAST AN ISOLATED DRY LIGHTNING THREAT OVER THE WC/SW HIGHER TERRAIN AS EARLY AS SATURDAY AFTERNOON OR EVENING. THIS WILL BE CLOSELY MONITORED. EVEN THE SLIGHTEST UPTICK IN LOWER/MID LEVEL MOISTURE IN THE PRESENCE OF VERY STEEP LAPSE RATES THAT ARE TYPICAL OF THE DEVELOPING PATTERN THIS WEEKEND SEEMS TO RESULT IN MORE THAN EXPECTED BUILDUPS/VIRGA AND DRY CG/S. WE SHALL SEE. SUNDAY AFTERNOON/EVENING LOOKING TO BE THE MORE CRITICAL DAY WITH RESPECT TO DRY LIGHTNING FOR THE WEST THOUGH MONDAY COULD BE FAIRLY ACTIVE EAST OF THE DIVIDE TO THE EAST SLOPES OF THE CENTRAL MOUNTAIN CHAIN AS DRIER AIR ADVANCES EASTWARD. IN THE MEANTIME...LARGE-SCALE UPPER TROUGH SLOWLY PIVOTING NORTHEAST FROM THE CENTRAL/NORTHERN ROCKIES EARLY THIS MORNING. BASE OF THE TROUGH TRANSLATED EASTWARD OVER OUR AREA THIS PAST NIGHT AND PRESENT INDICATIONS ARE THAT THE STRONGEST MID-LEVEL WINDS WILL PASS OVERHEAD BEFORE MIDDAY. THAT SAID...AN ANOMALOUSLY STRONG UPPER LEVEL JET ORIENTED NW TO SE FROM THE GREAT BASIN TO THE FOUR CORNERS REGION WILL NOT SHIFT NORTHWARD APPRECIABLY TODAY. AS A RESULT...WIND SPEEDS THOUGH A BIT LESS THAN YESTERDAY WILL STILL BE SIGNIFICANT WITH FREQUENT GUSTS OF 35-40 MPH ACROSS THE NORTH. SURFACE LOW NOT AS FAVORABLE EITHER. NO CHANGES TO THE FIRE WEATHER WATCH FOR FRIDAY THOUGH BELT OF STRONGEST WINDS DO SHIFT SOUTHWARD PER PREVIOUS FORECAST. VERY DEEP MIXING CONTINUES TODAY BEFORE MAX MIXING HEIGHTS TREND DOWNWARD SLIGHTLY ON FRIDAY. LOWEST RH VALUES CENTRAL VALLEY CORRIDOR AND IN THE EAST. EXTENDED MODELS STILL TRENDING DRIER/BREEZIER EARLY NEXT WORK WEEK FOLLOWING OUR LIGHTNING PERIOD. BACK TO VERY DEEP MIXING AND GUSTY AFTERNOON/EVENING PERIODS THOUGH TOO EARLY TO GAUGE STRENGTH OF ANY SUSTAINED WINDY PERIODS. KJ && .ABQ WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ101>104-106>108. FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR THE FOLLOWING ZONES...NMZ101>108. WIND ADVISORY FROM 10 AM THIS MORNING TO 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ510>516-523-527>529. && $$ 41
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1000 AM CDT THU MAY 30 2013 .UPDATE... ISSUED AT 1000 AM CDT THU MAY 30 2013 MORNING UPDATE FOCUSES ON FLOODING IN CLAY COUNTY MINNESOTA AND POP TRENDS. RADAR CONTINUES TO SHOW A BAND OF SHOWERS ACROSS NORTHWESTERN ZONES. INCREASED POPS IN THIS REGION AND DECREASED POPS ACROSS THE SOUTHERN HALF OF THE CWA. HRRR DOES SHOW REDEVELOPMENT OVER SOUTHEASTERN ZONES SO MAINTAINED LIKELIES...HOWEVER WENT DOWN TO 30 POPS FOR SOUTHEASTERN ND AND SOUTHERN VALLEY. WILL WAIT TO FURTHER ASSESS 12Z RUN BEFORE CHANGING ANYTHING BEYOND 00Z FRIDAY. REPORTS OF FIVE TO SEVEN INCHES ARE COMING IN ALONG THE BUFFALO RIVER BASIN TO INCLUDE THE CITIES OF AVERILL AND DILWORTH. WILL EXTEND WARNING AREA IN TIME BUT CHOP OFF CASS COUNTY AND NORMAN COUNTY...WHERE RADAR ESTIMATES ARE ABOUT FOUR INCHES OR LESS WITH NO REPORTS OF OVERLAND FLOODING FROM THOSE COUNTY MANAGERS. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 355 AM CDT THU MAY 30 2013 THE MAIN CHALLENGE WILL BE SHOWER AND THUNDERSTORM CHANCES INTO FRIDAY AND HEAVY RAIN POTENTIAL. THE MODELS ARE IN GOOD OVERALL AGREEMENT BUT NOT PICKING UP TOO WELL ON MESOSCALE FEATURES. FOR TODAY AND TONIGHT...EXPECT SHOWERS AND STORMS TO LIFT TO THE NORTH AND LIKELY BECOME MORE FOCUSED IN THE NORTHERN AREAS. THERE WILL BE A CHANCE FOR LOCALLY HEAVY RAINFALL NEAR ANY STORMS...GIVEN PWATS OVER 1.5 INCHES. THERE COULD BE SOME STRONGER STORMS THIS AFTERNOON IF SFC HEATING OCCURS...BUT I AGREE WITH SPC IN KEEPING JUST 5% PROBS FOR HAIL/WIND AND NO SLIGHT RISK AT THIS TIME. THINK THE MAIN ISSUE COULD BE HEAVY RAIN IF TRAINING ECHOES DEVELOPS. HARD TO PINPOINT WHERE THIS MAY OCCUR...SO NO FLOOD HEADLINES PLANNED...ALTHOUGH THERE COULD BE MORE FLOODING ISSUES NEAR PERSISTENT HEAVY RAIN TODAY AND TONIGHT. FOR FRIDAY...THE UPPER LOW WILL SLOWLY MOVE INTO THE AREA FROM THE WEST AND EXPECT MORE WRAPAROUND SHOWERS AND SOME THUNDER. AGAIN LOCALLY HEAVY RAINFALL IS POSSIBLE NEAR STRONGER SHOWERS AND STORMS. IT WILL BE COOLER THAN TODAY WITH WINDS SHIFTING TO THE NORTH BY AFTERNOON IN ALL BUT THE SOUTH AND EASTERN AREAS. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 355 AM CDT THU MAY 30 2013 FOR FRI NIGHT INTO SAT...WRAPAROUND SHOWERS WILL CONTINUE BEFORE IT DRIES OUT BY SAT AFTERNOON. FOR SUNDAY THROUGH WEDNESDAY...EXPECT A LOW AMPLITUDE LONG WAVE TROUGH OVER THE NORTHERN PLAINS TO SHIFT EAST. ECMWF AND GFS GENERALLY AGREE TIMING WISE HOWEVER THE GFS IS A HIGHER AMPLITUDE SOLUTION COMPARED TO THE ECMWF. WILL BLEND THE MODELS. ECMWF HAS SLOWED DOWN FROM MODEL RUN TO MODEL RUN WHILE THE GFS HAS SHIFTED PRECIP SOUTH WITH EACH RUN. WILL SLOW DOWN PRECIP FOR TUE AND DECREASE POPS A BIT FOR MON AND MON NIGHT. LITTLE CHANGE TO TEMPS FOR SUN THROUGH TUE. WED HIGH TEMP WAS INCREASED BY 3 DEGREES IN THE NORTHWEST ZONES AND A DEGREE OR TWO LOWER IN THE SOUTHERN ZONES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 1000 AM CDT THU MAY 30 2013 IFR TO MVFR CIGS WILL CONTINUE ACROSS MOST OF THE REGION THIS MORNING...WITH SLOW IMPROVEMENT TO MVFR OR VFR BY AFTERNOON. EXPECT A SHOWER OR STORM NEARLY ANYTIME THROUGH THE PERIOD...BUT TRIED TO INDICATE THE BEST POTENTIAL FOR RAIN. && .HYDROLOGY... ISSUED AT 355 AM CDT THU MAY 30 2013 A BAND OF HEAVY RAIN FELL OVERNIGHT FROM FARGO THROUGH NORTHEASTERN CLAY COUNTY. THIS HAS PROMPTED AN AREAL FLOOD WARNING FOR THE REGION. REPORTS OF OVERLAND FLOODING IN THE VICINITY OF AVERILL AND DILWORTH HAVE PROMPTED AN EXTENSION OF WARNING THROUGH 03Z FRIDAY. HAVE REMOVED CASS COUNTY ND AND NORMAN COUNTY MN FROM WARNING AREA. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...SPEICHER SHORT TERM...DK LONG TERM...HOPPES/DK AVIATION...JR HYDROLOGY...DK/SPEICHER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
736 AM EDT THU MAY 30 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED PATTERN. && .NEAR TERM /THROUGH TONIGHT/... THE AREAL DISTRIBUTION OF CLOUD COVER IS WORKING OUT ABOUT AS EXPECTED...WITH OVERCAST SKIES OVER THE SRN APPALACHAINS...THE WRN UPSTATE AND NE GA. THE MOISTURE MAY NOT BE AS SHALLOW AS I ORIGINALLY THOUGHT AND SOME LOCATIONS IN THIS AREA MAY BE CLOUDY THROUGH NOON. FARTHER TO THE EAST...INCLUDING THE WRN NC PIEDMONT AND THE NE UPSTATE...THE LLVLS ARE DRIER AND IT SHOULD BE MAINLY SUNNY EXPECT FOR SOME CIRRUS AND A FEW CU THAT WILL LIFT AN HOUR OR TWO AFTER SUNRISE. AS OF 440 AM EDT THURSDAY...MVFR CIGS ARE FILLING IN QUICKLY OVER NE GA AND WE APPEAR TO BE ON TRACK FOR A STRATUS DECK TO INVADE THE FORECAST AREA FROM THE SOUTHWEST OVER THE NEXT FEW HOURS. I DID TWEAK SKY COVER TO ACCOUNT FOR CURRENT TRENDS...HOWEVER. AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS RUNNING ABOUT A CATEGORY ABOVE NORMAL. WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN NC. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC. MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO GOING WITH A DRY FCST. ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL. OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA FOR SUNDAY INTO EARLY NEXT WEEK. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN. EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE NORMAL OVERNIGHT TEMPS. THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS WILL BE NEAR NORMAL. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AT KCLT...MVFR STRATUS HAS DEVELOPED ALONG THE BLUE RIDGE AND BACK ACROSS THE CENTRAL AND WESTERN UPSTATE...BUT THE RUC AND SREF IMPLY THAT THE LOW CLOUDS WILL STAY WEST OF THE AIRFIELD THIS MORNING. HOWEVER...THERE WILL BE SOME SHALLOW GROUND FOG AROUND THE REGION THIS MORNING. TYPICALLY THIS DOESN/T AFFECT KCLT AND NOTHING HAS BEEN INCLUDED. STRATUS LOOKS MORE LIKELY TONIGHT AND A LOT OF GUIDANCE IS POINTING TO CIGS IN THE IFR RANGE. I/VE HEDGED A LITTLE AT THIS POINT AND GONE WITH SCT010...BUT THIS ALMOST CERTAINLY OVERLY OPTIMISTIC. ELSEWHERE...IT/S INTERESTING THAT THE LATEST RUN OF THE SREF AS WELL AS THE HI RES WRF-NMM AND WRF-ARW ARE NOT DOING AS GOOD A JOB WITH THE ORIENTATION OF THE STRATUS DECK THAT HAS MOVED INTO THE REGION AS THEIR PREVIOUS RUNS. AT ANY RATE...AN MVFR DECK CURRENTLY COVERS THE UPSTATE AND UPPER FRENCH BROAD VALLEY FROM KGSP AND KAVL EASTWARD. THE CLOUDS HAVE LOWERED INTO THE IFR RANGE UPSTREAM OF THE REGION AT KGVL AND KAHN. KAND MAY SEE A PERIOD OF IFR...BUT I THINK MOST SITES WILL STAY BETWEEN 1200-1500 FEET. THE COLD COVER IS RATHER EXTENSIVE UPSTREAM. THE LATEST RUC 925 MB RH FIELD IMPLIES THAT WE MAY HOLD ON TO CIGS THROUGH NOON...THOUGH I THINK THEY WILL GRADUALLY RISE. STRATUS SHOULD BE EVEN MORE WIDESPREAD AND LOWER TONIGHT. THE LATEST SREF...NAM BUKFIT AND GFS MOS INDICATE THAT WE WILL SEE IFR CIGS. I HAVE INCLUDED THIS AT THE UPSTATE AND KAVL. I KEPT CIGS A BIT HIGHER AT KHKY...WHERE PROBS ARE A BIT LOWER...BUT I SUSPECT THEY WILL SEE IFR AS WELL. OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY. HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM THE TN VALLEY. CONFIDENCE TABLE... 11-17Z 17-23Z 23-05Z 05-11Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 90% KGSP LOW 58% HIGH 100% HIGH 100% HIGH 93% KAVL MED 67% HIGH 100% HIGH 100% HIGH 93% KHKY MED 72% HIGH 100% HIGH 100% MED 75% KGMU LOW 58% HIGH 100% HIGH 100% HIGH 95% KAND MED 74% HIGH 100% HIGH 100% HIGH 98% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...ARK NEAR TERM...MCAVOY SHORT TERM...ARK LONG TERM...ARK AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
640 AM EDT THU MAY 30 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL KEEP US DRY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE THROUGH THE END OF THE WEEK. THE HIGH MOVES OFF THE ATLANTIC COAST OVER THE WEEKEND...AND A COLD FRONT APPROACHES BY EARLY NEXT WEEK...RETURNING US TO AN UNSETTLED PATTERN. && .NEAR TERM /THROUGH TONIGHT/... THE AREAL DISTRIBUTION OF CLOUD COVER IS WORKING OUT ABOUT AS EXPECTED...WITH OVERCAST SKIES OVER THE SRN APPALACHAINS...THE WRN UPSTATE AND NE GA. THE MOISTURE MAY NOT BE AS SHALLOW AS I ORIGINALLY THOUGHT AND SOME LOCATIONS IN THIS AREA MAY BE CLOUDY THROUGH NOON. FARTHER TO THE EAST...INCLUDING THE WRN NC PIEDMONT AND THE NE UPSTATE...THE LLVLS ARE DRIER AND IT SHOULD BE MAINLY SUNNY EXPECT FOR SOME CIRRUS AND A FEW CU THAT WILL LIFT AN HOUR OR TWO AFTER SUNRISE. AS OF 440 AM EDT THURSDAY...MVFR CIGS ARE FILLING IN QUICKLY OVER NE GA AND WE APPEAR TO BE ON TRACK FOR A STRATUS DECK TO INVADE THE FORECAST AREA FROM THE SOUTHWEST OVER THE NEXT FEW HOURS. I DID TWEAK SKY COVER TO ACCOUNT FOR CURRENT TRENDS...HOWEVER. AS OF 300 AM EDT THURSDAY...MVFR LEVEL STRATUS IS EXPANDING ACROSS SOUTHERN AND CENTRAL GA EARLY THIS THURSDAY MORNING. THE SREF SHOWS A HIGH PROBABILITY THAT IT WILL CONTINUE TO EXPAND NORTH AND NORTHEAST...EVENTUALLY SPREADING ACROSS NE GA...THE WRN UPSTATE AND THE SRN NC MTNS. I/VE CARRIED MOSTLY CLOUDY SKIES EARLY IN THE DAY TO ACCOUNT FOR THIS...BUT THE CLOUD LAYER SHOULD BE SHALLOW AND SHOULD MIX INTO A CU FIELD FAIRLY QUICKLY BY LATE MORNING. OTHERWISE IT WILL BE DRY ACROSS THE ENTIRE FORECAST AREA TODAY WITH MAX TEMPS RUNNING ABOUT A CATEGORY ABOVE NORMAL. WE WILL PROBABLY SEE STRATUS DEVELOP AGAIN TONIGHT. IN FACT...WITH HIGHER BNDRY LAYER RH/S AND A STRONGER WIND FIELD...IT IS LIKELY TO COVER MOST OF THE FORECAST AREA. STILL...IT/S NOT A GIVEN THAT THIS WILL HAPPEN AND MY SKY COVER IS RATHER LOW...ESPECIALLY ACROSS WRN NC. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 245 AM THURSDAY...UPPER RIDGE WILL BEGIN TO BREAK DOWN AND SHIFT EAST FURTHER OFF THE ATLANTIC COAST DURING THE SHORT TERM...BUT OVERALL WILL CONTINUE TO INFLUENCE OUR SENSIBLE WX. LLVL FLOW WILL REMAIN LIGHT GENERALLY OUT OF THE S/SE OFF THE ATLANTIC. MODELS IN BETTER AGREEMENT ON MORNING STRATUS DEVELOPING AND BEING A LITTLE BIT MORE WIDESPREAD FRIDAY MORNING...BUT SHUD SCATTER OUT BY MIDDAY. FCST SNDGS SHOW WEAK CAPE WITH INHIBITION FRI AFTN...SO GOING WITH A DRY FCST. ON SATURDAY...ONCE AGAIN...GUIDANCE INDICATING MORNING STRATUS DEVELOPMENT...WITH INCREASE IN SOME MID-UPR MOISTURE AS WELL. OVERALL...STILL LOOKS LIKE ANOTHER DRY DAY...ALTHO WILL KEEP A SLGT CHC POP FOR THE NC MTNS...THANKS TO SOME INCREASED MOISTURE IN A VEERING SWLY LLVL FLOW. HIGHS BOTH DAYS WILL BE SIMILAR TO LAST COUPLE OF DAYS...ABOUT A CATEGORY OR TWO ABOVE NORMAL...WITH NEAR OR SLIGHTLY ABOVE NORMAL OVERNIGHT LOWS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY...UNSETTLED WEATHER LOOKS TO RETURN THE CWFA FOR SUNDAY INTO EARLY NEXT WEEK. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON SUNDAY...WITH A PLUME OF DEEP RH AND HEIGHT FALLS ENTERING THE NC MTNS BY PEAK HEATING. SO A SOLID CHC TO LOW-END LIKELY POPS FOR SUNDAY LOOKS GOOD. CONVECTION MAY LINGER INTO THE NIGHT IN THE MOIST AIR MASS WITH SOME UPR SUPPORT. THE FRONT IS PROGGED TO SETTLE ROUGHLY ALONG THE BLUE RIDGE ON MONDAY...WITH PLENTY OF AFTN INSTBY ONCE AGAIN. EXPECTING SCATTERED TO NUMEROUS SHWRS AND TSTMS TO DEVELOP...POSSIBLY MOST FAVORED IN THE PIEDMONT ON WARM SIDE OF THE FRONT. HIGHS WILL BE NEAR NORMAL BOTH DAYS...WITH SLIGHTLY ABOVE NORMAL OVERNIGHT TEMPS. THE FORECAST FOR TUESDAY AND WEDNESDAY WERE UNCHANGED...AS LATEST MODEL TRENDS AND THE 00Z WPC GRIDS ARE IN LINE WITH EARLIER THINKING. STILL EXPECTING THE FRONT TO SAG SE THRU THE CAROLINAS ON TUESDAY...WITH A LINGERING CHC POP MAINLY SE OF I-85. THEN JUST A SLGT CHC POP FOR MOST OF THE AREA ON WEDNESDAY...AS CANADIAN HIGH PRES BUILDS IN ACRS THE GREAT LAKES TO THE SOUTHEAST STATES. TEMPS WILL BE NEAR NORMAL. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AT KCLT...MVFR STRATUS HAS DEVELOPED ALONG THE BLUE RIDGE AND BACK ACROSS THE CENTRAL AND WESTERN UPSTATE...BUT THE RUC AND SREF IMPLY THAT THE LOW CLOUDS WILL STAY WEST OF THE AIRFIELD THIS MORNING. HOWEVER...THERE WILL BE SOME SHALLOW GROUND FOG AROUND THE REGION THIS MORNING. TYPICALLY THIS DOESN/T AFFECT KCLT AND NOTHING HAS BEEN INCLUDED. STRATUS LOOKS MORE LIKELY TONIGHT AND A LOT OF GUIDANCE IS POINTING TO CIGS IN THE IFR RANGE. I/VE HEDGED A LITTLE AT THIS POINT AND GONE WITH SCT010...BUT THIS ALMOST CERTAINLY OVERLY OPTIMISTIC. ELSEWHERE...IT/S INTERESTING THAT THE LATEST RUN OF THE SREF AS WELL AS THE HI RES WRF-NMM AND WRF-ARW ARE NOT DOING AS GOOD A JOB WITH THE ORIENTATION OF THE STRATUS DECK THAT HAS MOVED INTO THE REGION AS THEIR PREVIOUS RUNS. AT ANY RATE...AN MVFR DECK CURRENTLY COVERS THE UPSTATE AND UPPER FRENCH BROAD VALLEY FROM KGSP AND KAVL EASTWARD. THE CLOUDS HAVE LOWERED INTO THE IFR RANGE UPSTREAM OF THE REGION AT KGVL AND KAHN. KAND MAY SEE A PERIOD OF IFR...BUT I THINK MOST SITES WILL STAY BETWEEN 1200-1500 FEET. THE COLD COVER IS RATHER EXTENSIVE UPSTREAM. THE LATEST RUC 925 MB RH FIELD IMPLIES THAT WE MAY HOLD ON TO CIGS THROUGH NOON...THOUGH I THINK THEY WILL GRADUALLY RISE. STRATUS SHOULD BE EVEN MORE WIDESPREAD AND LOWER TONIGHT. THE LATEST SREF...NAM BUKFIT AND GFS MOS INDICATE THAT WE WILL SEE IFR CIGS. I HAVE INCLUDED THIS AT THE UPSTATE AND KAVL. I KEPT CIGS A BIT HIGHER AT KHKY...WHERE PROBS ARE A BIT LOWER...BUT I SUSPECT THEY WILL SEE IFR AS WELL. OUTLOOK...GENERALLY FAIR CONDITIONS ARE EXPECTED THROUGH SATURDAY. HOWEVER...RESTRICTIONS FROM MORNING STRATUS...AND POSSIBLY FOG...WILL CONTINUE EACH MORNING THRU SUNDAY. CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL INCREASE SIGNIFICANTLY BY SUNDAY AFTERNOON...AS A COLD FRONT APPROACHES FROM THE TN VALLEY. CONFIDENCE TABLE... 10-16Z 16-22Z 22-04Z 04-10Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 95% KGSP MED 61% HIGH 93% HIGH 100% HIGH 97% KAVL MED 65% HIGH 100% HIGH 100% HIGH 97% KHKY MED 73% HIGH 100% HIGH 100% MED 79% KGMU MED 63% HIGH 93% HIGH 100% HIGH 100% KAND MED 65% HIGH 93% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...LEV NEAR TERM...MCAVOY SHORT TERM...ARK LONG TERM...ARK AVIATION...MCAVOY
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1043 AM CDT THU MAY 30 2013 .UPDATE... WE ARE RAMPING UP THE SEVERE THREAT FOR SOUTH CENTRAL WI FOR THIS AFTERNOON. THERE IS A HIGH PROBABILITY OF STRONG THUNDERSTORMS IN THE UPPER MIDWEST...AND A GOOD CHANCE OF SEVERE WINDS IN SOUTH CENTRAL WI. SOUTHERN WISCONSIN IS BACK IN THE SLIGHT RISK FOR SEVERE WEATHER AREA TODAY/TONIGHT. A STRONG SHORTWAVE CURRENTLY OVER OKLAHOMA WILL BE SWINGING UP INTO IOWA AROUND 21Z THIS AFTERNOON. THERE IS A WEAKER SHORTWAVE OUT AHEAD OF THAT WHICH WILL GET INTO EASTERN IOWA/SOUTHERN WI JUST AFTER 18Z. THE LEADING SHORTWAVE WILL NEED TO BE WATCHED FOR EARLY AFTERNOON CONVECTION OVER SOUTH CENTRAL WI. THE MAIN STRONG SHORTWAVE WILL LIKELY DRIVE A THUNDERSTORM COMPLEX ACROSS ALL OF SOUTHERN WISCONSIN LATE AFTERNOON EARLY EVENING. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY SHOWS A TONGUE OF HIGH PROBABILITY OF UPDRAFT HELICITY VALUES GREATER THAN 25 M2/S2 STRETCHING INTO CENTRAL WISCONSIN. THE HIGHEST VALUES ARE FOCUSED OVER THE PLAINS AND EASTERN IOWA...BUT THE 60-70 PERCENTS OVER SOUTH CENTRAL WI ARE STILL VERY IMPRESSIVE. THE CRAVEN-WIEDENFELD AGGREGATE SEVERE PARAMETER WHICH COMPILES INGREDIENTS FOR SEVERE THUNDERSTORMS AND GIVES A SCORE/PERCENTAGE CONTINUES TO HAVE VERY HIGH VALUES IN SOUTHWEST AND SOUTH CENTRAL WI IN THE 75-82 PERCENT RANGE...WITH RUC13 VALUES EVEN HIGHER. IN ADDITION...CIPS ANALOGS SHOW A HISTORY OF SEVERE WEATHER OCCURRING WITH THE CURRENT SYNOPTIC PATTERN. MODE OF CONVECTION IS STILL IN QUESTION. THE MOST LIKELY MODE IS LINES OF STORMS PRODUCING BOWING SEGMENTS. THE SHEAR IS RELATIVELY WEAK OVER THE REGION AND UNIDIRECTIONAL. IT IS FORECAST TO STRENGTHEN THROUGH THE AFTERNOON...AS WILL LOW LEVEL WIND SHEAR...WHICH WOULD HELP CELLS REMAIN MORE DISCRETE OR HAVE JUST SMALL BOWING LINE SEGMENTS. TORNADO DEVELOPMENT WILL BE POSSIBLE GIVEN LOW LCL AND HIGH LOW LEVEL SHEAR. THE WIDESPREAD CUMULUS CLOUDS THAT DEVELOPED THIS MORNING WILL ACTUALLY HELP THE SEVERE SITUATION BY KEEPING US FROM MIXING OUT TOO MUCH AND ALLOWING THE DEWPOINTS TO REMAIN HIGH. THE 13Z HRRR IS SHOWING A MORE DISCRETE MODE OVER SOUTHERN WI EARLY THIS AFTERNOON...WITH A SQUALL LINE/MCS DEVELOPING WITH THE BIGGER VORT MAX LATE THIS AFTERNOON/EVENING. THE QUAD CITIES NWS OFFICE WILL BE DOING AN 18Z UPPER AIR SOUNDING TO ALLOW US TO BETTER ASSESS THE SEVERE POTENTIAL. && .AVIATION/18Z TAFS/... EXPECT GUSTS BETWEEN 25 AND 30 KTS TO LAST THROUGH MOST OF THE DAY. MVFR BROKEN CUMULUS CLOUDS DEVELOPED AND WILL GRADUALLY LIFT TO VFR BY 18Z. STORMS WILL DEVELOP OVER EASTERN IOWA AND MOVE NORTHEAST INTO SOUTHERN WISCONSIN EARLY THIS AFTERNOON. MADISON WILL HAVE THE BEST CHANCE FOR EARLIER THUNDERSTORMS. SOME MAY BE SEVERE. THEN ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED LATE AFTERNOON/EARLY EVENING AND THESE WILL LIKELY SPREAD ALL THE WAY INTO SOUTHEAST WI. STRAIGHT-LINE WINDS ARE THE MAIN SEVERE WEATHER THREAT. && .MARINE... GUSTY SOUTH WINDS DUE TO MIXING OVER THE LAND WILL AFFECT SHORELINE NEARSHORE AREAS ALL DAY TODAY. MAY NEED A SMALL CRAFT ADVISORY TO HANDLE THIS. WINDS WILL BE LESS GUSTY TOWARD THE OPEN WATERS. HOWEVER...THE TIGHT PRESSURE GRADIENT OVER THE LAKE WILL ALLOW SUSTAINED WINDS TO BE IN THE 15 TO 20 KNOT RANGE TODAY. STABLE AIR DOWN AT LAKE LEVEL WILL KEEP WAVES FROM RESPONDING TOO MUCH TO THE GUSTY WINDS. && .PREV DISCUSSION... /ISSUED 449 AM CDT THU MAY 30 2013/ TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM CONVECTION HAS LIFTED NORTH OF THE FORECAST AREA WITH SHORT WAVE/MCV AND ADDITIONAL SUPPORT FROM RIGHT ENTRANCE REGION OF UPPER JET. MODELS DAMPEN FIRST SHORT WAVE CURRENTLY DRIVING SRN PLAINS CONVECTION AND FOCUS ON WAVE NEAR THE PANHANDLE REGION THAT WILL SWING UP TOWARDS IA/NEB BY 00Z FRI AS 500 MB LOW GOES NEGATIVE-TILT. WITH COMBINATION OF CENTRAL PLAINS SHORT WAVE/MCV AND 850 MB JET MAX AND INSTABILITY ON AREA SOUNDINGS...THOUGH CAPE VALUES MAY BE A BIT TOO HIGH DUE TO GENEROUS SURFACE DEW POINTS...WILL FOLLOW CONSENSUS BLEND POPS AND INCREASE PRECIPITATION CHANCES RAPIDLY THROUGH THE MORNING. HIGH POPS CONTINUE INTO THE EVENING...THEN TAPER OFF AS FORCING WITH WAVE AND LOW-LEVEL JET MAX LIFT OFF TOP THE NORTHEAST. WILL HAVE TO WATCH WESTERN COUNTIES OF S CENTRAL WI FOR FLASH FLOODING POTENTIAL AFTER RECEIVING HEAVY RAIN WITH THE CONVECTION WEDNESDAY EVENING. LATEST SPC DAY 1 OUTLOOK HAS SHIFTED SLIGHT RISK TO THE SOUTHWEST OUT OF OF WISCONSIN AS FAVORABLE SHEAR FOR ROTATING CELLS LESSENS THROUGH THE DAY...BUT AN ISOLATED WIND/HAIL MAKER NOT OUT OF THE QUESTION. FRIDAY AND SATURDAY...FORECAST CONFIDENCE...MEDIUM SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY AS LOW PRESSURE OVER NORTH DAKOTA AND MINNESOTA REMAINS NEARLY STATIONARY. SHOWERS AND STORMS ARE THUS LIKELY ONCE AGAIN. THOUGH THE BEST LOW LEVEL FLOW WILL BE TO THE SOUTH AND EAST...STRONGER STORMS ARE NOT OUT OF THE QUESTION WITH SIMILAR UP TO 1000 J/KG OF SURFACE BASED CAPE...AND WIND SHEAR ACTUALLY A BIT HIGHER THAN PREVIOUS DAYS. LOOKS LIKE BEST CHANCE FOR SHOWERS AND STORMS WILL BE LATE AFTERNOON INTO THE NIGHT...AS ANOTHER SHORTWAVE ROTATES THROUGH THE AREA. TEMPERATURES WILL BE SIMILAR FRIDAY AS THURSDAY...PUSHING OR REACHING 80 MOST PLACES. PROBABLY A BIT TRICKY NEAR THE LAKE AGAIN UNDER SOUTHERLY WINDS...BUT MOST AREAS SHOULD SEE THE WARMER TEMPS. WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH SOUTHERN WISCONSIN BY SATURDAY NIGHT. MODELS HAVE SLOWED A BIT WITH THE FRONT...SO TEMPS AND POPS HAVE TRENDED IT BIT HIGHER WITH SOUTHERN WISCONSIN REMAINING IN THE WARM SECTOR A BIT LONGER. SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM MAIN UPPER LEVEL TROUGH AXIS WILL MOVE THROUGH SUNDAY...POSSIBLY BRINGING A FEW SHOWERS. COOLER AIR IS EXPECTED TO ARRIVE WITH THE SHORTWAVE...WITH TEMPERATURES FALLING BACK BELOW NORMAL. SHOULD BE PLEASANT MONDAY UNDER HIGH PRESSURE...WITH A CHANCE FOR SHOWERS AND STORMS RETURNING LATER TUESDAY INTO WEDNESDAY. HIGHS WILL LIKELY REMAIN A FEW DEGREES BELOW NORMAL THROUGH THE FIRST HALF OF NEXT WEEK. AVIATION/12Z TAFS/... WILL KEEP WIND SHEAR IN ALL OF THE TAFS...WITH WIND PROFILERS PICKING UP 35 TO 40 KT WINDS BETWEEN 1500-2000 FT...UNTIL SURFACE WINDS INCREASE WITH MIXING AFTER DAYBREAK. EXPECT SOUTHERLY GUSTS BETWEEN 25 AND 30 KTS BY MID-MORNING AND LASTING THROUGH MOST OF THE DAY. INCREASED LOW-LEVEL MOISTURE AND COOLING EFFECTS OF LAST NIGHT/S STORMS HAVE PRODUCED FOG AT KMSN WHICH SHOULD LIFT WITH INCREASING WINDS AFTER SUNRISE. OTHERWISE VFR CONDITIONS THROUGH MOST OF THE DAY. WHILE EXACT TIMING IS QUESTIONABLE...WEAK UPPER DISTURBANCE AND ANOTHER LOW-LEVEL JET MAX APPROACHING THE UPPER MIDWEST WILL BRING INCREASING CHANCES FOR THUNDERSTORMS. BEST CHANCES STAY WEST OF KMSN UNTIL MID-LATE MORNING...THEN SPREAD EAST AND INCREASE THROUGH THE AFTERNOON. SHOWERS AND STORMS MOST LIKELY FROM LATE AFTERNOON THROUGH THE EVENING BRINGING MVFR CIGS/VSBYS...POSSIBLY DROPPING TO IFR WITH HEAVY DOWNPOURS OF RAIN. WILL THEN KEEP MVFR CONDITIONS THROUGH THE REMAINDER OF THE FORECAST. MARINE... SOUTH WINDS WILL INCREASE RAPIDLY AFTER SUNRISE...WITH GUSTS TO 20 KNOTS BY MID TO LATE MORNING. PREVAILING WINDS HOLD JUST BELOW SMALL CRAFT CRITERIA...THOUGH THERE WILL BE A FEW GUSTS TO 25 KNOTS. HAVE ADDED A CAUTIONARY STATEMENT FOR SMALL CRAFT IN THE NEARSHORE FORECAST AND IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. EXPECT THUNDERSTORM CHANCES TO INCREASE THROUGH THE LATE MORNING AND AFTERNOON...BECOMING MOST LIKELY THIS EVENING. WHILE THE STORMS ARE EXPECTED TO STAY BELOW SEVERE LEVELS...GUSTY WINDS...SMALL HAIL AND VISIBILITY-REDUCING HEAVY RAINS ARE POSSIBLE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...REM FRIDAY THROUGH WEDNESDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 AM CDT THU MAY 30 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 333 AM CDT THU MAY 30 2013 CURRENTLY AS OF 0830Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED UPPER TROUGHING FROM THE NORTHEAST PACIFIC INTO THE NORTHERN ROCKIES WITH AN UPPER LOW IN NORTHEAST WYOMING...WHILE DOWNSTREAM RIDGING WAS PRESENT ACROSS THE EASTERN U.S.. ALSO TO NOTE ON WATER VAPOR IS A FAIRLY POTENT SHORTWAVE OVER THE TEXAS AND OKLAHOMA PANHANDLES IN THE BASE OF THIS TROUGHING. NEARLY UNIDIRECTIONAL SOUTH TO SOUTHWEST FLOW EXISTED BETWEEN THE TROUGHING AND RIDGING... WITH SOME VERY STRONG WINDS AT 850MB. VWP AND PROFILER DATA SHOWED SPEEDS OF 50-65 KT FROM CENTRAL OKLAHOMA INTO SOUTHERN MINNESOTA. THESE WINDS WERE TRANSPORTING COPIOUS AMOUNTS OF MOISTURE NORTHWARD...NOTED BY PRECIPITABLE WATER VALUES OF 1.5-1.75 INCHES OR 150-180 PERCENT OF NORMAL. NUMEROUS SHORTWAVES...SOME CONVECTIVELY INDUCED...RIDING THROUGH THE MID LEVEL FLOW HAS BEEN INTERACTING WITH THE MORE SUMMER-LIKE AIRMASS TO CONTINUE TO PRODUCE SCATTERED CLUSTERS OF SHOWERS AND THUNDERSTORMS. MUCH OF THE FORECAST AREA LIES IN THE WARM SECTOR OF A LOW PRESSURE SYSTEM BACK IN THE DAKOTAS. MAIN WARM FRONT HAS LIFTED INTO NORTHERN WISCONSIN WHILE THE COLD FRONT IS WELL BACK TO THE WEST IN CENTRAL SOUTH DAKOTA. MODELS ARE IN GOOD AGREEMENT ON THE SYNOPTICS THROUGH TONIGHT... INDICATING THAT THE UPPER TROUGHING FROM WYOMING INTO THE TEXAS PANHANDLE WILL SHIFT EAST NORTHEAST INTO THE FORECAST AREA BY 06Z TONIGHT. THERE ARE SOME DECENT 500MB HEIGHT FALLS BETWEEN 18Z-06Z OVER THE FORECAST AREA...ON THE ORDER OF 60-90 METERS. THE DPVA FROM THE APPROACH OF THIS UPPER TROUGH...AS WELL AS VARIOUS SHORTWAVES AND CONVECTIVELY INDUCED SHORTWAVES AHEAD OF IT...SUGGESTS PLENTY OF FORCING FOR CONVECTION. MODELS HAVE SHOWN THIS FOR MANY DAYS AS WELL. THIS FORCING MAY MAKE IT HARD TO BUILD A LOT OF INSTABILITY... COMPARED TO YESTERDAY WHERE WE HAD PLENTY OF SUNSHINE BEFORE CONVECTION ERUPTED. RAP/NAM/GFS SOUNDINGS ALL SUGGEST ANY 0-1 MLCIN FROM NOCTURNAL INFLUENCES BEING NEARLY COMPLETELY GONE BY 15Z. THEREFORE IT IS CONCEIVABLE FOR CONVECTION TO FIRE SHORTLY THEREAFTER WHEN 0-1 MLCAPE IS ONLY AT 800-1500 J/KG. HRRR/RAP MODELS SHOW CONVECTION FIRING IN THAT 15-16Z WINDOW...IN AGREEMENT WITH THE ABOVE ANALYSIS. THE CONVECTION MAY STABILIZE THINGS BRIEFLY...BUT PERSISTENT HEATING THROUGH THE DAY COMBINED WITH SOUTHERLY WARM ADVECTION OF INSTABILITY SHOULD PROVIDE FUEL TO CONTINUE PERIODS OF CONVECTION THROUGH THE DAY AND INTO THE EVENING. PASSAGE OF THE UPPER TROUGH AND NOCTURNAL COOLING SHOULD ALLOW CONVECTION TO SUBSIDE AFTER MIDNIGHT. REGARDING SEVERE POTENTIAL...THE LIMITATION OF BUILDING A LOT OF CAPE IS A HINDRANCE. 0-6KM SHEAR FROM THE 30.00Z NAM/GFS IS GENERALLY PROGGED AT 25-30 KT THROUGH THE DAY...FAVORING FOR MORE OF A MULTI-CELL SITUATION. WITH INSTABILITY STRUGGLING...NOT THINKING MUCH IN THE WAY FOR SEVERE HAIL. BULK OF THE AFOREMENTIONED 0-6KM SHEAR IS IN THE 0-3KM LAYER...AND COMBINED WITH 850MB WINDS PROGGED IN THE AFTERNOON AND EVENING OF 45-50 KT DOES BRING UP A CONCERN FOR THE STORMS TO PRODUCE STRONG TO DAMAGING WIND GUSTS. 0-1KM SHEAR IS QUITE HIGH AS WELL FOR THE AFTERNOON AND EVENING...SIMILAR TO 0-3KM OF 25-30KT...SO WE MAY WANT TO WATCH FOR POSSIBLE TORNADOES TOO. THIS WOULD BE ESPECIALLY TRUE ALONG ANY CONVECTIVE OUTFLOW BOUNDARY AND/OR IF WE CAN GET MORE DAYTIME HEATING THAN EXPECTED. ON THE FLOODING FRONT...MORE INFORMATION CAN BE FOUND IN THE HYDROLOGY SECTION BELOW. BRIEFLY...THE PATTERN TODAY INTO THIS EVENING IS VERY FAVORABLE FOR STORMS TO TRAIN ACROSS THE SAME AREAS AS THEY MARCH SOUTH TO NORTH. WITH PRECIPITABLE WATER VALUES STAYING UP IN THE 1.5-1.75 INCH RANGE ANY STORM CAN PRODUCE HEAVY RAIN. WITH GROUNDS ALREADY SATURATED...FLASH FLOODING IS CERTAINLY POSSIBLE... ESPECIALLY SOUTH OF I-90 WHICH WAS REALLY IMPACTED FROM YESTERDAY INTO LAST NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 333 AM CDT THU MAY 30 2013 LOW PRESSURE OVER THE EASTERN DAKOTAS PUSHES SOUTHEAST LATE FRIDAY MORNING INTO FRIDAY AFTERNOON DRIVING THE FRONT ACROSS THE FORECAST AREA. DEPENDING ON THE TIMING OF THIS FRONT...SEVERE WEATHER POSSIBLE ON FRIDAY. FORECAST MODELS ARE IN REASONABLE AGREEMENT...SHOWING 0-3 KM MUCAPE VALUES CLIMBING TO 2000 TO 3000 J/KG. SHEAR IS ALSO RAMPING UP LATE FRIDAY MORNING INTO FRIDAY AFTERNOON WITH 0-6 KM BULK SHEAR INCREASING TO 45 TO 55 KTS. THE HIGHEST INSTABILITY APPEARS TO BE OVER FAR NORTHEAST IOWA AND INTO EXTREME SOUTHWEST WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON THIS OVER THE NEXT FEW MODEL RUNS. AT THIS TIME...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN HAZARDS FROM THESE STORMS. BUT AGAIN...THE SEVERE THREAT AREA WILL DEPEND ON WHERE THE BOUNDARY IS LOCATED LATE FRIDAY MORNING INTO FRIDAY AFTERNOON AND HOW MUCH SURFACE HEATING IS REALIZED. A DRY SLOT PUSHES INTO THE FORECAST AREA LATE FRIDAY NIGHT AS THE LOW PUSHES EAST INTO THE WESTERN GREAT LAKES. THERE SHOULD BE A DRY PERIOD AS THE LOW MOVES IN...BUT THEN SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP ON SATURDAY AS THE LOW SLIDES ACROSS THE REGION. AN UNSEASONABLY COOL AIRMASS MOVES INTO REGION ON SUNDAY. 850 MB TEMPERATURES FALL TO 0 C OVER NORTHERN WISCONSIN AND TO AROUND 2 C OVER NORTHEAST IOWA. THIS WILL SET THE STAGE FOR A CHILLY NIGHT ACROSS THE AREA SUNDAY NIGHT INTO EARLY MONDAY MORNING. ECMWF 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO AROUND -1.5...INDICATIVE OF AN ANOMALOUSLY COLD AIRMASS. TEMPERATURES WILL PLUMMET INTO THE UPPER 30S OVER FAR NORTHERN WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON LOWS OVER NORTH CENTRAL AND CENTRAL WISCONSIN WHERE TYPICAL COLD SPOTS SUCH AS SPARTA AND BLACK RIVER FALLS COULD SEE LOWS DIP INTO THE UPPER 30S...LEADING TO FROST FORMATION. COOL HIGH PRESSURE REMAINS OVER THE REGION THROUGH TUESDAY...WITH HIGHS ONLY IN THE 60S. HIGH PRESSURE PUSHES EAST OF THE REGION LATE TUESDAY INTO WEDNESDAY AS A TROUGH DIGS INTO THE DAKOTAS. SOUTHERLY FLOW DEVELOPS OVER THE AREA HELPING TO USHER IN WARMER TEMPERATURES. THE TROUGH WILL MOVE INTO THE FORECAST AREA LATE TUESDAY NIGHT THROUGH WEDNESDAY BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 600 AM CDT THU MAY 30 2013 DIFFICULT FORECAST FOR TIMING OF OCCASIONAL TO SCATTERED -SHRA/TS TODAY INTO TONIGHT. CHAOTIC SKY...LEFT OVER SURFACE BOUNDARIES...AND UPPER LEVEL PIECES OF ENERGY COULD ALSO SERVE AS PCPN TRIGGERS. WHERE THESE WILL BE...TIMING...AND WHEN SHRA/TS FIRE IS NOT CLEAR. MEANWHILE...THE MAIN IMPETUS WILL BE WHERE THE LOW LEVEL MOISTURE TRANSPORT INTERACTS WITH ANY OF THESE FEATURES. CONFIDENCE IS HIGHEST FOR THE AFTERNOON AND EVENING HOURS...BUT ONLY FOR VCTS/VCSH AT THIS TIME. UPDATES WILL BE NEEDED FOR KRST/KLSE TO BETTER REFINE THE PCPN THREATS AS THEY BECOME MORE EVIDENT. LOOK FOR AN INCREASE IN WINDS EARLY THIS MORNING AS MIXING KICKS IN AND 40 KTS OF WIND SITS AROUND 2 KFT. LLWS STILL A THREAT UNTIL 14Z...BUT THERE SHOULD BE ENOUGH MIXING AT THE SFC - THUS INCREASE IN THE SFC BASED WIND - THAT LLWS IN THE TAFS WILL NO LONGER BE NEEDED. WINDS WILL STAY UP FOR MUCH OF TONIGHT AS TIGHT PRESSURE GRADIENT HOLDS ACROSS THE REGION. BUFKIT SOUNDINGS AND SREF MODEL GUIDANCE ALSO FAVOR A LOWERING OF THE CLOUD DECK INTO THE MVFR CATEGORY. NOT ENTIRELY SOLD ON THIS...BUT ENOUGH SIGNALS FAVOR IT THAT WILL ADD FOR THE OVERNIGHT HOURS. && .HYDROLOGY...TODAY AND TONIGHT ISSUED AT 333 AM CDT THU MAY 30 2013 HEAVY RAIN FELL ACROSS THE AREA WEDNESDAY AFTERNOON AND EVENING WITH RAINFALL AMOUNTS OF 2 TO 3 INCHES REPORTED ACROSS PORTIONS OF NORTHEAST IOWA...SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN...WITH LOCALLY HIGHER AMOUNTS OF 4 INCHES REPORTED. AN ADDITIONAL 1 TO 2 INCHES OF RAIN IS EXPECTED ACROSS THE AREA TODAY THROUGH THIS EVENING...WHICH COULD LEAD TO FLASH FLOODING. IT WILL NOT TAKE MUCH RAIN OVER THE SATURATED SOILS TO CREATE FLOODING ISSUES. ALSO...AREA RIVERS WILL SEE RISES AND POSSIBLE FLOODING WITH ANY ADDITIONAL RAINFALL RECEIVED. HAVE EXPANDED THE FLASH FLOOD WATCH NORTHWARD...INCLUDING AREAS ALONG AND SOUTHWEST OF INTERSTATE 94 CORRIDOR EXCLUDING JUNEAU COUNTY && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WIZ032>034-041-042- 053>055-061. MN...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR IAZ008>011-018-019- 029-030. && $$ SHORT TERM...AJ/WETENKAMP LONG TERM....WETENKAMP AVIATION.....RIECK HYDROLOGY....WETENKAMP
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1255 PM EDT THU MAY 30 2013 .SYNOPSIS... HIGH PRESSURE WILL LINGER ACROSS THE CENTRAL ATLANTIC INTO THIS WEEKEND, BRINGING INCREASING HEAT AND HUMIDITY TO THE MID ATLANTIC STATES. EARLY NEXT WEEK, A LOW PRESSURE SYSTEM EMERGING FROM THE GREAT LAKES WILL SEND A COLD FRONT THROUGH OUR REGION BY MONDAY. HIGH PRESSURE SPREADING SOUTH FROM CENTRAL CANADA IS THEN EXPECTED TO BUILD TOWARD OUR REGION THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO SIGNIFICANT CHANGES WILL BE MADE WITH THE NEXT ESTF. LOOKS LIKE THERE IS A BIT OF A SHORT WAVE ON THE WATER VAPOR IMAGERY AND CU WEST OF US LOOK A BIT MORE ROBUST THAN THEY WERE AT THIS TIME YESTERDAY. BASED ON THE 12Z SOUNDINGS, WE NUDGED MAX TEMPS EVER SO SLIGHTLY HIGHER AND PROGRESSED THEM UPWARD A BIT FASTER. MAX HEAT INDICES ARE IN THE LOWER 90S. TEMPERATURES NEAR THE WATER SHOULD BE SEVERAL DEGREES COOLER THAN INLAND. LATEST MESOSCALE MODELS RUN CONTINUE TO SUPPORT THE THINKING OF ISOLATED OR SLIGHT CHANCE CONVECTION LATER TODAY NORTHWEST. 12Z SOUNDINGS SHOW IAD AND APG AS CAPPED, BUT CAPPING NOT AS STRONG AT SITES FARTHER TO THE NORTH AND CONVECTIVE TEMP EXPECTED TO BE REACHED. ON POPS, THE MID LEVEL RIDGE DOES BUILD TODAY OVER OUR AREA, AND A RELATIVELY DRY SOUNDING DOES RESULT IN A RATHER HIGH LFC. HOWEVER, WE THINK WE END UP WITH SOME CAPE AND NOT A LOT OF CIN DURING THE AFTERNOON EVEN AFTER ADJUSTING FOR LOWER DEW POINTS. ALSO, THERE SEEMS TO BE SOME WEAK ENERGY MOVING ALONG THE SKIRT OF THE RIDGE THAT IS WEAKLY APPARENT ON WATER VAPOR IMAGERY AND THAT COULD WORK WITH THE INSTABILITY TO TRIGGER CONVECTION. SPC HAS ALMOST THE ENTIRE AREA UNDER A GENERAL RISK OF CONVECTION TODAY; WE JUST PUT SLIGHT CHANCE POPS BACK INTO THE AREA NORTHWEST OF THE FALL LINE. ON WINDS, WE SHOULD SEE A SOUTHWEST TO WEST WIND THAT PEAKS A BIT ABOVE 10 MPH TODAY. THE H925 WINDS ARE IN OPPOSITION TO ANY SEA/BAY BREEZE AND FORECAST TO BE AROUND 15 KT. THAT IS RIGHT ON THE EDGE OF STOPPING IT FROM MAKING MUCH PROGRESS INLAND. SINCE THE LAND/WATER TEMPERATURE DISCONTINUITY IS GOING TO BE CONSIDERABLE, WE DID FORECAST IT TO MAKE A LITTLE MORE PROGRESS INLAND THAN WE MIGHT HAVE LATER IN THE WARM SEASON. WE AREN`T FORECASTING ANY CONVECTION WITH THE SEA BREEZE AT THIS POINT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... WHATEVER ENERGY IS AVAILABLE TO TRIGGER ANYTHING SHOULD BE GONE BY DUSK, AND WE CARRY A DRY THURSDAY NIGHT. THE WINDS MAY DIE OFF A BIT MORE QUICKLY THAN THEY DID EARLY THIS MORNING, AND SO WE ALLOW FOR A BIT MORE RADIATING AND LEAN MODESTLY TOWARD COOLER GUIDANCE. WE DON`T CARRY ANY FOG OR HAZE IN THIS FORECAST. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... FOR THE FIRST PART OF THE LONG TERM PERIOD, OUR REGION WILL BE IN THE MIDST OF THE FIRST HEAT WAVE OF THE SEASON AS SURFACE HIGH PRESSURE WILL BE FOUND TO OUR EAST ACROSS THE CENTRAL ATLANTIC, WITH STRONG MID-LEVEL RIDGING ALOFT. THIS WILL PROMOTE AN INCREASING SOUTHWESTERLY FLOW THROUGH THE MID ATLANTIC REGION, WITH 850MB AND 925MB MODEL TEMPERATURE DATA SUPPORTING MAXIMUM TEMPERATURES ACROSS THE FORECAST AREA REACHING THE LOWER 90S FRIDAY AND FOR MUCH OF THE AREA AGAIN ON SATURDAY. DEWPOINTS THROUGH THIS TIME FRAME WILL MAINLY BE IN THE LOWER TO PERHAPS MIDDLE 60S, YIELDING HEAT INDEX VALUES IN THE LOWER 90S EACH AFTERNOON. WE WILL CONTINUE A MENTION IN OUR HAZARDOUS WEATHER OUTLOOK HIGHLIGHTING THIS MULTI-DAY HOT AND SOMEWHAT MUGGY AIRMASS. GOING INTO SUNDAY, THIS OVERALL PATTERN WILL BEGIN TO BREAK DOWN, AS SURFACE HIGH PRESSURE WILL DRIFT FARTHER EAST INTO THE CENTRAL ATLANTIC AND THE MID-LEVEL RIDGE WILL ALSO BEGIN TO PUSH OFFSHORE. MEANWHILE, AN AREA OF LOW PRESSURE WILL BE EMERGING FROM AROUND THE GREAT LAKES SUNDAY AND TRACKING INTO SOUTHEASTERN CANADA THROUGH MONDAY, ALLOWING A TRAILING COLD FRONT TO APPROACH OUR REGION FROM THE NORTHWEST. THERE LOOKS TO BE AMPLE INSTABILITY AND LOW LEVEL MOISTURE IN PLACE AHEAD OF THE APPROACHING FRONTAL BOUNDARY FOR POTENTIALLY STRONG CONVECTIVE ACTIVITY, AND WE STEADILY INCREASE POPS FROM NORTHWEST TO SOUTHEAST THROUGH THE COURSE OF SUNDAY INTO SUNDAY NIGHT. MODEL DIFFERENCES STILL EXIST BETWEEN THE ECMWF, GFS, AND OTHERS REGARDING THE TIMING OF THE FRONTAL PASSAGE THROUGH THE REGION MONDAY, AND WITH THIS UNCERTAINTY IN MIND, WE HAVE KEPT HIGH CHANCE TO LIKELY POPS IN PLACE FOR THE BETTER PART OF MONDAY ACROSS THE FORECAST AREA FOR SCATTERED SHWR/T-STORM ACTIVITY. FOLLOWING THE FRONTAL PASSAGE, THERE IS FAIRLY GOOD MODEL AGREEMENT AS AN AREA OF HIGH PRESSURE FROM CENTRAL CANADA IS PROGGED TO SPREAD SOUTH AND EAST FROM THE LATTER PART OF MONDAY THROUGH THE MID-WEEK PERIOD. THIS WILL BRING A NOTICEABLE CHANGE IN AIRMASS TO OUR REGION, WITH MAXIMUM TEMPERATURES RETURNING TO MORE SEASONAL LEVELS. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 18Z TAFS WILL HAVE VFR CONDITIONS FORECAST THROUGH THE EVENING FOR ALL TERMINALS AND VFR CONDITIONS ON FRIDAY. FOR THIS AFTERNOON, NO CIGS ARE FORECAST. SOME HIGH BASED (5K TO 6K) SCATTERED CUMULUS CLOUDS ARE EXPECTED WITH WEST TO SOUTHWEST WINDS AROUND 10 KTS. WE ARE BRINGING A SEA BREEZE FRONT TO KACY AT 21Z AND A BAY BREEZE FRONT TO KILG AT 22Z. BECAUSE OF THE WINDS ABOVE THE BOUNDARY LAYER BEING WEST, WE ARE NOT EXPECTING THE SEA BREEZE FRONT TO MAKE MUCH HEADWAY BEYOND THE IMMEDIATE COASTAL COUNTIES. ISOLATED THUNDERSTORMS ARE EXPECTED NORTHWEST OF THE TERMINALS THIS AFTERNOON AND EARLY EVENING, BUT OVERALL COVERAGE AND CONFIDENCE THAT THEY WILL MAKE IT TO THE TERMINALS IS TOO LOW TO INCLUDE. LOWEST CONFIDENCE AT KABE AND KRDG. FOR THIS EVENING, ANY CUMULUS CLOUDS AROUND SHOULD DISSIPATE RAPIDLY AND JUST SOME CIRRUS IS EXPECTED. WINDS SHOULD BECOME LIGHTER FROM THE SOUTHWEST AND LIGHT AND VARIABLE AT SOME OF THE OUTLYING TERMINALS AND AIRPORTS. THIS SHOULD CONTINUE OVERNIGHT. ALSO OVERNIGHT WE ARE FORECASTING SOME MVFR CONDITIONS LATE AT KABE AND KRDG. CONFIDENCE SHOULD BE VIEWED AS AVERAGE. ANOTHER VFR DAY ON FRIDAY. WE ARE EXPECTING EVEN LESS CUMULUS BASED COVERAGE AND SLIGHTLY STRONGER WINDS WITH THE DIRECTION SLIGHTLY MORE TOWARD THE SOUTH. WIND SPEEDS IN THE LAST FORECAST GROUP ARE MORE REPRESENTATIVE OF THE LATE MORNING AND AFTERNOON EXPECTATIONS. OUTLOOK... FRIDAY NIGHT AND SATURDAY...MAINLY VFR CONDITIONS WITH SOUTHWESTERLY WINDS. SOME LOCAL REDUCED VSBYS POSSIBLE IN MORNING HAZE. SUNDAY AND MONDAY...MOSTLY VFR, EXCEPT TIMES OF POSSIBLE IFR/MVFR IN SCATTERED SHWRS/T-STORMS, ESPECIALLY FROM SUNDAY AFTN THROUGH MONDAY MORNING. && .MARINE... A MARINE LAYER SHOULD BE FAIRLY STRONG TODAY. WINDS ABOVE THE SURFACE ARE NOT FORECAST TO BE THAT ROBUST, SO WE ARE FORECASTING A SOUTHWEST WIND THAT IS NOTICEABLE BUT BELOW THE ADVISORY CRITERION. A SEA/BAY BREEZE MAY MAKE MODEST PROGRESS OUT FROM THE COASTLINE AND UP THE BAY, AND WINDS THERE MAY COME AROUND TO SOUTH. GIVEN THE LATER HRRR WE WERE SLIGHTLY MORE AGGRESSIVE BRINGING A BAY BREEZE UP THE DELAWARE. SEAS WERE RUNNING AROUND 3 FT OVER THE ATLANTIC WATERS EARLY THIS MORNING. AS THE PREVIOUS FORECASTER NOTED, WAVE WATCH GUIDANCE IS VERIFYING TOO HIGH WITH SWELLS. WE CARRY SUB-ADVISORY SEAS THROUGH THE TONIGHT. OUTLOOK... SUB-SCA CONDITIONS EXPECTED FOR OUR WATERS THROUGH FRIDAY AND MOST OF SATURDAY AS AN AREA OF HIGH PRESSURE LINGERS ACROSS THE CENTRAL ATLANTIC. BY SATURDAY NIGHT AND INTO SUNDAY, HIGH PRESSURE WILL BE DRIFTING FARTHER EAST AND AWAY FROM THE REGION, WITH A COLD FRONT APPROACHING THE AREA FROM THE NORTHWEST DURING SUNDAY. WE ANTICIPATE WIND GUSTS AND SEAS TO REACH SMALL CRAFT ADVISORY LEVELS DURING THIS TIME FRAME, AND THESE CONDITIONS WILL MOST LIKELY LAST INTO MONDAY, AS WELL. SCATTERED SHWRS AND T-STORMS WILL ALSO REDUCE VISIBILITIES FROM LATE SUNDAY THROUGH MONDAY FOR OUR WATERS, AS THE FRONT APPROACHES AND TRACKS THROUGH THE REGION. && .RIP CURRENTS... WE CARRY A LOW PROBABILITY OF RIP CURRENTS TODAY. RIP CURRENT AWARENESS WEEK IS JUNE 2 THROUGH 8. PSA`S WILL AIR ON KPHI NWR AND POST DAILY AROUND 545 AM. THERE WILL BE A SHORT AWARENESS PRESS CONFERENCE IN SURF CITY, LBI ON TUE JUNE 4 AT 2 PM FOR THOSE MEDIA REPRESENTATIVES WHO ARE INTERESTED IN RAISING RIP CURRENT AWARENESS AND IN CONDITIONS FAVORING LIFE THREATENING DANGER IN THE UNGUARDED OCEAN SURF ZONE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLINE NEAR TERM...DELISI/GIGI SHORT TERM...DELISI LONG TERM...KLINE AVIATION...GIGI/KLINE MARINE...DELISI/KLINE RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1209 PM EDT THU MAY 30 2013 .SYNOPSIS... HIGH PRESSURE WILL LINGER ACROSS THE CENTRAL ATLANTIC INTO THIS WEEKEND, BRINGING INCREASING HEAT AND HUMIDITY TO THE MID ATLANTIC STATES. EARLY NEXT WEEK, A LOW PRESSURE SYSTEM EMERGING FROM THE GREAT LAKES WILL SEND A COLD FRONT THROUGH OUR REGION BY MONDAY. HIGH PRESSURE SPREADING SOUTH FROM CENTRAL CANADA IS THEN EXPECTED TO BUILD TOWARD OUR REGION THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO SIGNIFICANT CHANGES WILL BE MADE WITH THE NEXT ESTF. LOOKS LIKE THERE IS A BIT OF A SHORT WAVE ON THE WATER VAPOR IMAGERY AND CU WEST OF US LOOK A BIT MORE ROBUST THAN THEY WERE AT THIS TIME YESTERDAY. BASED ON THE 12Z SOUNDINGS, WE NUDGED MAX TEMPS EVER SO SLIGHTLY HIGHER AND PROGRESSED THEM UPWARD A BIT FASTER. MAX HEAT INDICES ARE IN THE LOWER 90S. TEMPERATURES NEAR THE WATER SHOULD BE SEVERAL DEGREES COOLER THAN INLAND. LATEST MESOSCALE MODELS RUN CONTINUE TO SUPPORT THE THINKING OF ISOLATED OR SLIGHT CHANCE CONVECTION LATER TODAY NORTHWEST. 12Z SOUNDINGS SHOW IAD AND APG AS CAPPED, BUT CAPPING NOT AS STRONG AT SITES FARTHER TO THE NORTH AND CONVECTIVE TEMP EXPECTED TO BE REACHED. ON POPS, THE MID LEVEL RIDGE DOES BUILD TODAY OVER OUR AREA, AND A RELATIVELY DRY SOUNDING DOES RESULT IN A RATHER HIGH LFC. HOWEVER, WE THINK WE END UP WITH SOME CAPE AND NOT A LOT OF CIN DURING THE AFTERNOON EVEN AFTER ADJUSTING FOR LOWER DEW POINTS. ALSO, THERE SEEMS TO BE SOME WEAK ENERGY MOVING ALONG THE SKIRT OF THE RIDGE THAT IS WEAKLY APPARENT ON WATER VAPOR IMAGERY AND THAT COULD WORK WITH THE INSTABILITY TO TRIGGER CONVECTION. SPC HAS ALMOST THE ENTIRE AREA UNDER A GENERAL RISK OF CONVECTION TODAY; WE JUST PUT SLIGHT CHANCE POPS BACK INTO THE AREA NORTHWEST OF THE FALL LINE. ON WINDS, WE SHOULD SEE A SOUTHWEST TO WEST WIND THAT PEAKS A BIT ABOVE 10 MPH TODAY. THE H925 WINDS ARE IN OPPOSITION TO ANY SEA/BAY BREEZE AND FORECAST TO BE AROUND 15 KT. THAT IS RIGHT ON THE EDGE OF STOPPING IT FROM MAKING MUCH PROGRESS INLAND. SINCE THE LAND/WATER TEMPERATURE DISCONTINUITY IS GOING TO BE CONSIDERABLE, WE DID FORECAST IT TO MAKE A LITTLE MORE PROGRESS INLAND THAN WE MIGHT HAVE LATER IN THE WARM SEASON. WE AREN`T FORECASTING ANY CONVECTION WITH THE SEA BREEZE AT THIS POINT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... WHATEVER ENERGY IS AVAILABLE TO TRIGGER ANYTHING SHOULD BE GONE BY DUSK, AND WE CARRY A DRY THURSDAY NIGHT. THE WINDS MAY DIE OFF A BIT MORE QUICKLY THAN THEY DID EARLY THIS MORNING, AND SO WE ALLOW FOR A BIT MORE RADIATING AND LEAN MODESTLY TOWARD COOLER GUIDANCE. WE DON`T CARRY ANY FOG OR HAZE IN THIS FORECAST. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... FOR THE FIRST PART OF THE LONG TERM PERIOD, OUR REGION WILL BE IN THE MIDST OF THE FIRST HEAT WAVE OF THE SEASON AS SURFACE HIGH PRESSURE WILL BE FOUND TO OUR EAST ACROSS THE CENTRAL ATLANTIC, WITH STRONG MID-LEVEL RIDGING ALOFT. THIS WILL PROMOTE AN INCREASING SOUTHWESTERLY FLOW THROUGH THE MID ATLANTIC REGION, WITH 850MB AND 925MB MODEL TEMPERATURE DATA SUPPORTING MAXIMUM TEMPERATURES ACROSS THE FORECAST AREA REACHING THE LOWER 90S FRIDAY AND FOR MUCH OF THE AREA AGAIN ON SATURDAY. DEWPOINTS THROUGH THIS TIME FRAME WILL MAINLY BE IN THE LOWER TO PERHAPS MIDDLE 60S, YIELDING HEAT INDEX VALUES IN THE LOWER 90S EACH AFTERNOON. WE WILL CONTINUE A MENTION IN OUR HAZARDOUS WEATHER OUTLOOK HIGHLIGHTING THIS MULTI-DAY HOT AND SOMEWHAT MUGGY AIRMASS. GOING INTO SUNDAY, THIS OVERALL PATTERN WILL BEGIN TO BREAK DOWN, AS SURFACE HIGH PRESSURE WILL DRIFT FARTHER EAST INTO THE CENTRAL ATLANTIC AND THE MID-LEVEL RIDGE WILL ALSO BEGIN TO PUSH OFFSHORE. MEANWHILE, AN AREA OF LOW PRESSURE WILL BE EMERGING FROM AROUND THE GREAT LAKES SUNDAY AND TRACKING INTO SOUTHEASTERN CANADA THROUGH MONDAY, ALLOWING A TRAILING COLD FRONT TO APPROACH OUR REGION FROM THE NORTHWEST. THERE LOOKS TO BE AMPLE INSTABILITY AND LOW LEVEL MOISTURE IN PLACE AHEAD OF THE APPROACHING FRONTAL BOUNDARY FOR POTENTIALLY STRONG CONVECTIVE ACTIVITY, AND WE STEADILY INCREASE POPS FROM NORTHWEST TO SOUTHEAST THROUGH THE COURSE OF SUNDAY INTO SUNDAY NIGHT. MODEL DIFFERENCES STILL EXIST BETWEEN THE ECMWF, GFS, AND OTHERS REGARDING THE TIMING OF THE FRONTAL PASSAGE THROUGH THE REGION MONDAY, AND WITH THIS UNCERTAINTY IN MIND, WE HAVE KEPT HIGH CHANCE TO LIKELY POPS IN PLACE FOR THE BETTER PART OF MONDAY ACROSS THE FORECAST AREA FOR SCATTERED SHWR/T-STORM ACTIVITY. FOLLOWING THE FRONTAL PASSAGE, THERE IS FAIRLY GOOD MODEL AGREEMENT AS AN AREA OF HIGH PRESSURE FROM CENTRAL CANADA IS PROGGED TO SPREAD SOUTH AND EAST FROM THE LATTER PART OF MONDAY THROUGH THE MID-WEEK PERIOD. THIS WILL BRING A NOTICEABLE CHANGE IN AIRMASS TO OUR REGION, WITH MAXIMUM TEMPERATURES RETURNING TO MORE SEASONAL LEVELS. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. WE AREN`T FORECASTING ANY CEILINGS THROUGH THE TAF PERIOD. SOME VFR CUMULUS IS FORECAST FOR TODAY. WE CAN`T RULE CONVECTION OUT COMPLETELY, BUT THE PROBABILITY OF IT AS OF THIS WRITING IS TOO LOW TO CARRY IN THE TAFS. WINDS ARE FORECAST TO BE FROM THE SOUTHWEST TO WEST AND PICK UP TO AROUND OR A BIT ABOVE 10 KT AFTER DAYBREAK. WHETHER A SEA/BAY BREEZE MAKES IT TO ACY, MIV AND ILG IS UNCERTAIN. GIVEN THE EXPECTED STRONG TEMPERATURE DIFFERENCE BETWEEN THE WATER AND INLAND AND THE WINDS ABOVE THE SURFACE, WE FORECAST A BRIEF PERIOD LATE THIS AFTERNOON AND EARLY THIS EVENING WHEN WINDS AT ACY AND ILG COME AROUND TO SOUTH. CONFIDENCE IN THAT IS MODERATE AT BEST. OUTLOOK... FRIDAY AND SATURDAY...MAINLY VFR CONDITIONS WITH SOUTHWESTERLY WINDS. SOME LOCAL REDUCED VSBYS POSSIBLE EACH MORNING IN HAZE. SUNDAY AND MONDAY...MOSTLY VFR, EXCEPT TIMES OF POSSIBLE IFR/MVFR IN SCATTERED SHWRS/T-STORMS, ESPECIALLY FROM SUNDAY AFTN THROUGH MONDAY MORNING. && .MARINE... A MARINE LAYER SHOULD BE FAIRLY STRONG TODAY. WINDS ABOVE THE SURFACE ARE NOT FORECAST TO BE THAT ROBUST, SO WE ARE FORECASTING A SOUTHWEST WIND THAT IS NOTICEABLE BUT BELOW THE ADVISORY CRITERION. A SEA/BAY BREEZE MAY MAKE MODEST PROGRESS OUT FROM THE COASTLINE AND UP THE BAY, AND WINDS THERE MAY COME AROUND TO SOUTH. GIVEN THE LATER HRRR WE WERE SLIGHTLY MORE AGGRESSIVE BRINGING A BAY BREEZE UP THE DELAWARE. SEAS WERE RUNNING AROUND 3 FT OVER THE ATLANTIC WATERS EARLY THIS MORNING. AS THE PREVIOUS FORECASTER NOTED, WAVE WATCH GUIDANCE IS VERIFYING TOO HIGH WITH SWELLS. WE CARRY SUB-ADVISORY SEAS THROUGH THE TONIGHT. OUTLOOK... SUB-SCA CONDITIONS EXPECTED FOR OUR WATERS THROUGH FRIDAY AND MOST OF SATURDAY AS AN AREA OF HIGH PRESSURE LINGERS ACROSS THE CENTRAL ATLANTIC. BY SATURDAY NIGHT AND INTO SUNDAY, HIGH PRESSURE WILL BE DRIFTING FARTHER EAST AND AWAY FROM THE REGION, WITH A COLD FRONT APPROACHING THE AREA FROM THE NORTHWEST DURING SUNDAY. WE ANTICIPATE WIND GUSTS AND SEAS TO REACH SMALL CRAFT ADVISORY LEVELS DURING THIS TIME FRAME, AND THESE CONDITIONS WILL MOST LIKELY LAST INTO MONDAY, AS WELL. SCATTERED SHWRS AND T-STORMS WILL ALSO REDUCE VISIBILITIES FROM LATE SUNDAY THROUGH MONDAY FOR OUR WATERS, AS THE FRONT APPROACHES AND TRACKS THROUGH THE REGION. && .RIP CURRENTS... WE CARRY A LOW PROBABILITY OF RIP CURRENTS TODAY. RIP CURRENT AWARENESS WEEK IS JUNE 2 THROUGH 8. PSA`S WILL AIR ON KPHI NWR AND POST DAILY AROUND 545 AM. THERE WILL BE A SHORT AWARENESS PRESS CONFERENCE IN SURF CITY, LBI ON TUE JUNE 4 AT 2 PM FOR THOSE MEDIA REPRESENTATIVES WHO ARE INTERESTED IN RAISING RIP CURRENT AWARENESS AND IN CONDITIONS FAVORING LIFE THREATENING DANGER IN THE UNGUARDED OCEAN SURF ZONE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLINE NEAR TERM...DELISI/GIGI SHORT TERM...DELISI LONG TERM...KLINE AVIATION...DELISI/KLINE MARINE...DELISI/KLINE RIP CURRENTS...GIGI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
539 PM CDT THU MAY 30 2013 .DISCUSSION... 504 PM CDT HAVE DECIDED TO EXPAND THE CURRENT FLASH FLOOD WATCH...TO INCLUDE THE ENTIRE CWA. WAS ON THE FENCE EARLIER WITH REGARDS TO EXPANDING THE CURRENT FLASH FLOOD WATCH FOR THE REMAINDER OF THE CWA...BUT WITH LATEST TRENDS THIS PAST AFTERNOON...HAVE DECIDED TO INCLUDE THE ENTIRE CWA. THE THUNDERSTORMS THIS PAST AFTERNOON HAVE BEEN VERY GOOD RAIN PRODUCERS...WHICH WILL LIKELY CONTINUE OVER THE NEXT COUPLE OF HOURS AS PWATS REMAIN RATHER HIGH. ALSO...MONITORING THE CONVECTIVE LINE TO THE WEST AND ITS MOVEMENT EAST INTO THE CWA. LATEST TRENDS AND SHORT TERM GUIDANCE ARE HINTING AT THE POSSIBILITY OF MORE TRAINING ACROSS THE CWA...WITH CURRENT FLOW IN PLACE...DEFINITELY SEEMS REASONABLE. RODRIGUEZ //PREV DISCUSSION... 400 PM CDT MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER. HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE PROGRESSIVE AREA OF THUNDERSTORMS. CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY GOING INTO WESTERN ILLINOIS AND EASTERN IOWA. HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN GROWTH IN BOTH INTENSITY AND COVERAGE. EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS ALSO INCREASING. THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING. HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH. THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH THETAE AIR INTO THE REGION. RODRIGUEZ EXTENDED PERIOD...SUNDAY THROUGH THURSDAY... BY DAYBREAK SUNDAY THE UPPER RIDGE IS TO HAVE PROGRESSED EASTWARD TO OVER THE UPPER MIDWEST AND MID MS VALLEY WITH A SURFACE TROUGH/SECONDARY COLD FRONT JUST TO THE NORTHWEST AND NORTH OF THE LOCAL FORECAST AREA. THIS TROUGH/FRONT IS PROGGED TO MOVE ACROSS ALL OF THE FA DURING THE SUNDAY MORNING AS THE UPPER TROUGH CONTINUES ON TO OVER THE UPPER GREAT LAKES AND LOWER OH VALLEY BY EVENING. UNTIL THE TROUGH AXIS MOVES A BIT FURTHER EAST OF THE IMMEDIATE AREA THERE WILL BE A LINGERING CHANCE OF SHOWERS DURING SUNDAY MORNING. THE SECONDARY COLD FRONT WILL REINFORCE THE COLD AIR ADVECTION THAT WILL HAVE STARTED TO OCCUR LATE SATURDAY AND SATURDAY NIGHT WITH THE INITIAL COLD FRONT. BETWEEN THE PAIR OF FRONT 850HPA TEMPERATURES ARE PROGGED TO FALL AROUND 10 DEGREES C FROM 18Z SATURDAY TO 00Z MONDAY......DOWN TO AROUND +4 OR +5C. WITH COOL HIGH PRESSURE BUILDING OVER THE AREA TEMPERATURES WILL BE COOL SUNDAY AND MONDAY WITH HIGHS ONLY IN THE 60S...WITH LAKESIDE MAX TEMPERATURES LIKELY TO ONLY BE IN THE 55-60F RANGE AS A LONG FETCH DOWN LAKE MICHIGAN BRINGS AIR ADDITIONALLY COOLED BY THE STILL CHILLY LAKE ASHORE SUNDAY. WHILE THE SURFACE RIDGE AXIS WILL BE MOVING OVER WI AND WESTERN IL DURING MONDAY ALLOWING WINDS TO SLACKEN...A WEAK NE SYNOPTIC FLOW WILL STILL BE IN PLACE AIDED BY A LAKE BREEZE. THE FURTHER EASTWARD PROGRESS OF THE UPPER TROUGH IS TO BE SLOW AS A CLOSED LOW TO FORM OVER SOUTHERN HUDSON BAY/NORTHERN ONTARIO IS PROGGED TO BE DROP SOUTH...THEN SOUTHEAST AND EAST OVER ONTARIO SATURDAY NIGHT THROUGH MONDAY NIGHT. AS THE UPPER TROUGH/LOW MOVES FURTHER EAST A WEAK UPPER RIDGE WILL MOVE OVER THE REGION TUESDAY AS ANOTHER UPPER LOW MOVES EAST OVER THE FAR SOUTHERN CANADIAN PRAIRIE/FAR NORTHERN PLAINS. THIS WILL ALLOW A BIT OF MODERATION IN TEMPERATURES TUESDAY AND WEDNESDAY AS EAST-SOUTHEAST WINDS BECOMES SOUTHEASTERLY AND INCREASING THOUGH THIS LOW LEVEL FLOW WILL KEEP THE IL SHORE...ESPECIALLY THE FAR NORTHERN PART....STILL CHILLY. INLAND AREAS SHOULD PEAK IN THE UPPER 60S AND LOWER 70S TUESDAY... AND A COUPLE DEGREES WARMER WEDNESDAY. WITH CONTINUED WARM AIR ADVECTION AHEAD OF THE APPROACHING UPPER LOW/TROUGH THE WARMING TREND WILL CONTINUE THURSDAY WITH MOST LOCATIONS REACHING THE MID AND UPPER 70S THOUGH THERE WILL STILL BE AN EASTERLY COMPONENT TO THE LOW LEVEL FLOW TO KEEP THE IL SHORELINE IN THE 60S. TRS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * APPROACHING LINE OF STORMS / LARGE OW ECHO ON WEATHER RADAR / EXPECTED TO ACCELERATE ACROSS NORTHERN ILLINOIS THIS EVENING. * GUST FRONT AHEAD OF LINE OF STORMS MAY PRODUCE DAMAGING WIND GUSTS... IN ADDITIONAL TO BRIEF TORRENTIAL RAINFALL. * ONGOING SCATTERED THUNDERSTORMS CONTINUING ALTHOUGH DECREASING IN COVERAGE INTO THE EVENING AHEAD OF APPROACHING LINE OF STORMS. ED F //DISCUSSION...UPDATED 18Z... AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS POSSIBLE AND GUSTY SOUTHERLY WINDS. SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG AS TODAY. SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA. WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY. THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH RESPECT TO PERIODIC CONVECTIVE CHANCES. BMD //ORD AND MDW CONFIDENCE...UPDATED 22Z... * MEDIUM TO HIGH CONFIDENCE IN SCATTERED TSTMS CONTINUING THROUGH THE EVENING... BUT WITH DECREASE IN COVERAGE OF SCATTERED CELLS IN ADVANCE OF LARGE LINE OF STORMS. * MEDIUM TO HIGH CONFIDENCE THAT APPROACHING LINE OF STORMS WILL CONTINUE ACROSS NORTHERN ILLINOIS THIS EVENING. * MEDIUM TO HIGH CONFIDENCE THAT LINE OF STORMS WILL MAINTAIN INTENSITY AS IT MOVES EAST THROUGH 03Z. * MEDIUM CONFIDENCE IN TIMING OF LINE OF TSTMS IMPACTING TERMINALS AROUND MID EVENING. * LOW CONFIDENCE IN STRENGTH OF WIND GUSTS TO BE EXPECTED AT TERMINALS AS GUST FRONT WITH LINE OF STORMS ADVANCES. * MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE IN TIMING. * MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS. ED F //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... * FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA. POSSIBLE WITH MVFR CIGS/VIS. * SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR. * MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL. * LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA. KREIN && .MARINE... 1259 PM CDT THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS. ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF THE LAKE...AREAS OF DENSE FOG CONTINUE. VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE. FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS GENERALLY IN THE 15-25KT. THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY THAT IS IN EFFECT. THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY WITH MUCH COOLER AIR FLOWING OVER THE LAKE. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 7 AM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
510 PM CDT THU MAY 30 2013 .DISCUSSION... 504 PM CDT HAVE DECIDED TO EXPAND THE CURRENT FLASH FLOOD WATCH...TO INCLUDE THE ENTIRE CWA. WAS ON THE FENCE EARLIER WITH REGARDS TO EXPANDING THE CURRENT FLASH FLOOD WATCH FOR THE REMAINDER OF THE CWA...BUT WITH LATEST TRENDS THIS PAST AFTERNOON...HAVE DECIDED TO INCLUDE THE ENTIRE CWA. THE THUNDERSTORMS THIS PAST AFTERNOON HAVE BEEN VERY GOOD RAIN PRODUCERS...WHICH WILL LIKELY CONTINUE OVER THE NEXT COUPLE OF HOURS AS PWATS REMAIN RATHER HIGH. ALSO...MONITORING THE CONVECTIVE LINE TO THE WEST AND ITS MOVEMENT EAST INTO THE CWA. LATEST TRENDS AND SHORT TERM GUIDANCE ARE HINTING AT THE POSSIBILITY OF MORE TRAINING ACROSS THE CWA...WITH CURRENT FLOW IN PLACE...DEFINITELY SEEMS REASONABLE. RODRIGUEZ && .PREV DISCUSSION... 400 PM CDT MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER. HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE PROGRESSIVE AREA OF THUNDERSTORMS. CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY GOING INTO WESTERN ILLINOIS AND EASTERN IOWA. HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN GROWTH IN BOTH INTENSITY AND COVERAGE. EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS ALSO INCREASING. THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING. HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH. THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH THETAE AIR INTO THE REGION. RODRIGUEZ EXTENDED PERIOD...SUNDAY THROUGH THURSDAY... BY DAYBREAK SUNDAY THE UPPER RIDGE IS TO HAVE PROGRESSED EASTWARD TO OVER THE UPPER MIDWEST AND MID MS VALLEY WITH A SURFACE TROUGH/SECONDARY COLD FRONT JUST TO THE NORTHWEST AND NORTH OF THE LOCAL FORECAST AREA. THIS TROUGH/FRONT IS PROGGED TO MOVE ACROSS ALL OF THE FA DURING THE SUNDAY MORNING AS THE UPPER TROUGH CONTINUES ON TO OVER THE UPPER GREAT LAKES AND LOWER OH VALLEY BY EVENING. UNTIL THE TROUGH AXIS MOVES A BIT FURTHER EAST OF THE IMMEDIATE AREA THERE WILL BE A LINGERING CHANCE OF SHOWERS DURING SUNDAY MORNING. THE SECONDARY COLD FRONT WILL REINFORCE THE COLD AIR ADVECTION THAT WILL HAVE STARTED TO OCCUR LATE SATURDAY AND SATURDAY NIGHT WITH THE INITIAL COLD FRONT. BETWEEN THE PAIR OF FRONT 850HPA TEMPERATURES ARE PROGGED TO FALL AROUND 10 DEGREES C FROM 18Z SATURDAY TO 00Z MONDAY......DOWN TO AROUND +4 OR +5C. WITH COOL HIGH PRESSURE BUILDING OVER THE AREA TEMPERATURES WILL BE COOL SUNDAY AND MONDAY WITH HIGHS ONLY IN THE 60S...WITH LAKESIDE MAX TEMPERATURES LIKELY TO ONLY BE IN THE 55-60F RANGE AS A LONG FETCH DOWN LAKE MICHIGAN BRINGS AIR ADDITIONALLY COOLED BY THE STILL CHILLY LAKE ASHORE SUNDAY. WHILE THE SURFACE RIDGE AXIS WILL BE MOVING OVER WI AND WESTERN IL DURING MONDAY ALLOWING WINDS TO SLACKEN...A WEAK NE SYNOPTIC FLOW WILL STILL BE IN PLACE AIDED BY A LAKE BREEZE. THE FURTHER EASTWARD PROGRESS OF THE UPPER TROUGH IS TO BE SLOW AS A CLOSED LOW TO FORM OVER SOUTHERN HUDSON BAY/NORTHERN ONTARIO IS PROGGED TO BE DROP SOUTH...THEN SOUTHEAST AND EAST OVER ONTARIO SATURDAY NIGHT THROUGH MONDAY NIGHT. AS THE UPPER TROUGH/LOW MOVES FURTHER EAST A WEAK UPPER RIDGE WILL MOVE OVER THE REGION TUESDAY AS ANOTHER UPPER LOW MOVES EAST OVER THE FAR SOUTHERN CANADIAN PRAIRIE/FAR NORTHERN PLAINS. THIS WILL ALLOW A BIT OF MODERATION IN TEMPERATURES TUESDAY AND WEDNESDAY AS EAST-SOUTHEAST WINDS BECOMES SOUTHEASTERLY AND INCREASING THOUGH THIS LOW LEVEL FLOW WILL KEEP THE IL SHORE...ESPECIALLY THE FAR NORTHERN PART....STILL CHILLY. INLAND AREAS SHOULD PEAK IN THE UPPER 60S AND LOWER 70S TUESDAY... AND A COUPLE DEGREES WARMER WEDNESDAY. WITH CONTINUED WARM AIR ADVECTION AHEAD OF THE APPROACHING UPPER LOW/TROUGH THE WARMING TREND WILL CONTINUE THURSDAY WITH MOST LOCATIONS REACHING THE MID AND UPPER 70S THOUGH THERE WILL STILL BE AN EASTERLY COMPONENT TO THE LOW LEVEL FLOW TO KEEP THE IL SHORELINE IN THE 60S. TRS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND OVERNIGHT. * COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF AFTERNOON. * INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE SURFACE WIND GUSTS TO 50 KTS. ED F //DISCUSSION...UPDATED 18Z... AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS POSSIBLE AND GUSTY SOUTHERLY WINDS. SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG AS TODAY. SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA. WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY. THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH RESPECT TO PERIODIC CONVECTIVE CHANCES. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH GENERAL INCREASING TREND IN COVERAGE. * LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC TERMINALS. * MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE THIS EVENING. * MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE IN TIMING. * MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS. ED F //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... * FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA. POSSIBLE WITH MVFR CIGS/VIS. * SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR. * MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL. * LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA. KREIN && .MARINE... 1259 PM CDT THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS. ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF THE LAKE...AREAS OF DENSE FOG CONTINUE. VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE. FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS GENERALLY IN THE 15-25KT. THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY THAT IS IN EFFECT. THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY WITH MUCH COOLER AIR FLOWING OVER THE LAKE. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM SATURDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM SATURDAY. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 7 AM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
401 PM CDT THU MAY 30 2013 .DISCUSSION... 400 PM CDT MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER. HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE PROGRESSIVE AREA OF THUNDERSTORMS. CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY GOING INTO WESTERN ILLINOIS AND EASTERN IOWA. HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN GROWTH IN BOTH INTENSITY AND COVERAGE. EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS ALSO INCREASING. THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING. HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH. THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH THETAE AIR INTO THE REGION. RODRIGUEZ EXTENDED PERIOD...SUNDAY THROUGH THURSDAY... BY DAYBREAK SUNDAY THE UPPER RIDGE IS TO HAVE PROGRESSED EASTWARD TO OVER THE UPPER MIDWEST AND MID MS VALLEY WITH A SURFACE TROUGH/SECONDARY COLD FRONT JUST TO THE NORTHWEST AND NORTH OF THE LOCAL FORECAST AREA. THIS TROUGH/FRONT IS PROGGED TO MOVE ACROSS ALL OF THE FA DURING THE SUNDAY MORNING AS THE UPPER TROUGH CONTINUES ON TO OVER THE UPPER GREAT LAKES AND LOWER OH VALLEY BY EVENING. UNTIL THE TROUGH AXIS MOVES A BIT FURTHER EAST OF THE IMMEDIATE AREA THERE WILL BE A LINGERING CHANCE OF SHOWERS DURING SUNDAY MORNING. THE SECONDARY COLD FRONT WILL REINFORCE THE COLD AIR ADVECTION THAT WILL HAVE STARTED TO OCCUR LATE SATURDAY AND SATURDAY NIGHT WITH THE INITIAL COLD FRONT. BETWEEN THE PAIR OF FRONT 850HPA TEMPERATURES ARE PROGGED TO FALL AROUND 10 DEGREES C FROM 18Z SATURDAY TO 00Z MONDAY......DOWN TO AROUND +4 OR +5C. WITH COOL HIGH PRESSURE BUILDING OVER THE AREA TEMPERATURES WILL BE COOL SUNDAY AND MONDAY WITH HIGHS ONLY IN THE 60S...WITH LAKESIDE MAX TEMPERATURES LIKELY TO ONLY BE IN THE 55-60F RANGE AS A LONG FETCH DOWN LAKE MICHIGAN BRINGS AIR ADDITIONALLY COOLED BY THE STILL CHILLY LAKE ASHORE SUNDAY. WHILE THE SURFACE RIDGE AXIS WILL BE MOVING OVER WI AND WESTERN IL DURING MONDAY ALLOWING WINDS TO SLACKEN...A WEAK NE SYNOPTIC FLOW WILL STILL BE IN PLACE AIDED BY A LAKE BREEZE. THE FURTHER EASTWARD PROGRESS OF THE UPPER TROUGH IS TO BE SLOW AS A CLOSED LOW TO FORM OVER SOUTHERN HUDSON BAY/NORTHERN ONTARIO IS PROGGED TO BE DROP SOUTH...THEN SOUTHEAST AND EAST OVER ONTARIO SATURDAY NIGHT THROUGH MONDAY NIGHT. AS THE UPPER TROUGH/LOW MOVES FURTHER EAST A WEAK UPPER RIDGE WILL MOVE OVER THE REGION TUESDAY AS ANOTHER UPPER LOW MOVES EAST OVER THE FAR SOUTHERN CANADIAN PRAIRIE/FAR NORTHERN PLAINS. THIS WILL ALLOW A BIT OF MODERATION IN TEMPERATURES TUESDAY AND WEDNESDAY AS EAST-SOUTHEAST WINDS BECOMES SOUTHEASTERLY AND INCREASING THOUGH THIS LOW LEVEL FLOW WILL KEEP THE IL SHORE...ESPECIALLY THE FAR NORTHERN PART....STILL CHILLY. INLAND AREAS SHOULD PEAK IN THE UPPER 60S AND LOWER 70S TUESDAY... AND A COUPLE DEGREES WARMER WEDNESDAY. WITH CONTINUED WARM AIR ADVECTION AHEAD OF THE APPROACHING UPPER LOW/TROUGH THE WARMING TREND WILL CONTINUE THURSDAY WITH MOST LOCATIONS REACHING THE MID AND UPPER 70S THOUGH THERE WILL STILL BE AN EASTERLY COMPONENT TO THE LOW LEVEL FLOW TO KEEP THE IL SHORELINE IN THE 60S. TRS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND OVERNIGHT. * COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF AFTERNOON. * INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE SURFACE WIND GUSTS TO 50 KTS. ED F //DISCUSSION...UPDATED 18Z... AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS POSSIBLE AND GUSTY SOUTHERLY WINDS. SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG AS TODAY. SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA. WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY. THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH RESPECT TO PERIODIC CONVECTIVE CHANCES. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH GENERAL INCREASING TREND IN COVERAGE. * LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC TERMINALS. * MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE THIS EVENING. * MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE IN TIMING. * MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS. ED F //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... * FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA. POSSIBLE WITH MVFR CIGS/VIS. * SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR. * MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL. * LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA. KREIN && .MARINE... 1259 PM CDT THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS. ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF THE LAKE...AREAS OF DENSE FOG CONTINUE. VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE. FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS GENERALLY IN THE 15-25KT. THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY THAT IS IN EFFECT. THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY WITH MUCH COOLER AIR FLOWING OVER THE LAKE. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM SATURDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 7 AM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
329 PM CDT THU MAY 30 2013 .DISCUSSION... 326 PM CDT MAIN FORECAST CONCERNS REMAIN TIED TO THE ACTIVE WEATHER PATTERN EXPECTED THROUGH THE START OF THE WEEKEND...WITH ROUNDS OF HEAVY RAINFALL LIKELY AS WELL AS CONTINUED CHANCES FOR SEVERE WEATHER. HAVE NOT EXPANDED THE FFA WATCH AT THIS TIME WITH MORE WIDESPREAD HEAVY RAINFALL AND FLOODING NOT APPEARING LIKELY UNTIL LATER FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS IS NOT TO SAY THAT LOCALIZED FLOODING COULD NOT OCCUR WITH ANY POSSIBLE STRONG THUNDERSTORMS TONIGHT. A MORE LIKELY SCENARIO AT THIS TIME IS WITH THE CURRENT SCATTERED DEVELOPMENT TO BE REPLACED WITH A MORE PROGRESSIVE AREA OF THUNDERSTORMS. CURRENT ISOLATED TO SCATTERED ACTIVITY ACROSS THE CWA WILL CONTINUE TO INCREASE IN COVERAGE THIS EVENING...AS LARGE SCALE FORCING INCREASES WITH THE APPROACH A FAIRLY STOUT MID LEVEL WAVE PROPAGATING NORTH THROUGH CENTRAL ILLINOIS. AREAS WHICH CONTINUE TO BE FAVORED ARE LOCATIONS ALONG AND WEST OF A LINE FROM CRYSTAL LAKE SOUTH TO GIBSON CITY IN ILLINOIS. LATEST RAP ANALYSIS SHOWS MODERATE INSTABILITY IN PLACE WITH MLCAPE AROUND 2000 J/KG...AND WITH MID/LOW LEVEL LAPSE RATES EXPECTED TO ONLY INCREASE OVER THE NEXT COUPLE OF HOURS. THIS INCREASING FORCING AND INSTABILITY WILL AID FURTHER DEVELOPMENT/EXPANSION OF CURRENT ACTIVITY ONGOING ACROSS THE WESTERN HALF OF THE CWA. DEEP LAYER SHEAR REMAINS MEAGER AT 25-30KT PRIMARILY OVER THE WESTERN CWA WHILE 0-1KM SHEAR ALSO REMAINS HIGHEST ALONG OR JUST WEST OF THE CWA...ESPECIALLY GOING INTO WESTERN ILLINOIS AND EASTERN IOWA. HOWEVER...SHORT TERM GUIDANCE CONTINUES TO SHOW AN INCREASE IN BOTH DEEP LAYER SHEAR AND LOW LEVEL SHEAR ACROSS THE CURRENT WATCH AREA THROUGH THE REMAINDER OF THE AFTERNOON. THIS WILL HELP FOR MORE ORGANIZED AND LONGER LIVED DEVELOPMENT ACROSS THE WESTERN CWA...LEAVING THE THREAT OF HAIL/DAMAGING WINDS AS WELL AS POSSIBLE TORNADOES. ALTHOUGH MORE ORGANIZED DEVELOPMENT IS MORE LIKELY FOR THE WESTERN HALF OF THE CWA...SHORT TERM GUIDANCE IS HINTING AT A SLIGHT INCREASE IN DEEP LAYER SHEAR MORE TOWARDS FAR NORTHEAST ILLINOIS. THIS SLIGHT INCREASE COINCIDING WITH THE CURRENT CAPE IN PLACE...COULD FAVOR SOME ISOLATED STRONGER DEVELOPMENT IN THAT LOCATION IN THE NEXT COUPLE OF HOURS. WILL NEED CONTINUE TO MONITOR DEVELOPMENT IN THAT LOCATION...WHICH WOULD INCLUDE THE CITY OF CHICAGO/METRO AREA LATE THIS AFTERNOON INTO THE EARLY EVENING...AS I COULD EASILY FORESEE AN UPSCALE IN GROWTH IN BOTH INTENSITY AND COVERAGE. EVEN IF THAT DOES NOT MATERIALIZE THROUGH LATE THIS AFTERNOON...CONTINUE TO MONITOR A LARGER LINE OF THUNDERSTORMS SITUATED FROM SOUTHERN IOWA SOUTH INTO MISSOURI. THIS LINE IS TIED MORE CLOSELY TO FAIRLY STRONG MID LEVEL WAVE LIFTING NORTHEAST OUT KANSAS AND ATTENDANT SURFACE TROUGH/BOUNDARY FROM IOWA INTO MISSOURI. ALL GUIDANCE IS SHOWING THIS LINE OF THUNDERSTORMS WILL INCREASE IN INTENSITY OVER THE NEXT COUPLE OF HOURS...WHICH WOULD MAKE SENSE AS THIS LINE OF THUNDERSTORMS MOVES FURTHER EAST/NORTHEAST INTO A MORE UNSTABLE ENVIRONMENT. STRONG FORCING OWING TO LARGE SCALE SUPPORT AND LOW/MID LEVEL CONVERGENCE SHOULD AID IN THIS LINE OF THUNDERSTORMS FURTHER BLOSSOMING AS IT MOVES TOWARDS THE WESTERN ILLINOIS...ESPECIALLY AS DEEP LAYER SHEAR IS ALSO INCREASING. THERE IS STILL SOME UNCERTAINTY AS TO THE WHOLE EVOLUTION OF THIS LINE OF THUNDERSTORMS AS IT WORKS ITS WAY TOWARDS NORTHERN ILLINOIS THIS EVENING...MAINLY IN THE STRENGTH OF THIS COMPLEX AND POTENTIAL SEVERE THREAT. ALTHOUGH THERE WILL BE SOME SLIGHT DIMINISHING TREND WITH THE CURRENT INSTABILITY IN PLACE...FEEL THAT IT WILL MORE THAN SUFFICE TO HELP KEEP THIS LINE SHIFTING EAST. ALSO...SHORT TERM GUIDANCE IS INDICATING THAT 0-3KM BULK SHEAR WILL INCREASE TOWARDS THE 00Z TIME FRAME THIS EVENING...WHICH WOULD ACT TO HELP FOR ORGANIZATION AND INCREASE IN THREAT FOR LINEAR STRUCTURES/STRONG DAMAGING WINDS. SO HAVE TRENDED MORE PESSIMISTIC...WITH THINKING THAT THIS LINE AND STRONG DAMAGING WINDS COULD MOVE ACROSS NORTHERN ILLINOIS THIS EVENING. HAVE ALSO TRENDED MORE TOWARDS THE HRRR...WITH SYSTEM TIMING THINKING THAT IT SHOULD BE KNOCKING ON THE WESTERN CWA DOORSTEPS BY 00-01Z AND THEN CONTINUE EAST TOWARDS NORTHEAST ILLINOIS THROUGH THE SEVERAL HOURS THERE AFTER. BEYOND THAT TIME FRAME...CONFIDENCE LOWERS WITH REGARDS TO THE STRENGTH OF THIS SYSTEM. NONETHELESS...HEAVY RAINFALL AND FLASH FLOODING COULD BECOME ISSUES OVERNIGHT TONIGHT ESPECIALLY AS PWATS ARE AT OR JUST ABOVE 1.7 INCHES AND 850MB DEW POINTS REMAIN RATHER HIGH. THUNDERSTORM COMPLEX IS THEN EXPECTED TO SHIFT EAST OF THE CWA BY EARLY FRIDAY MORNING...WITH A DRYING TREND EXPECTED DURING THAT TIME FRAME. THIS SHOULD NOT LAST TOO LONG WITH DRY CONDITIONS ONLY EXPECTED THROUGH MID DAY AS ATTENTION QUICKLY SHIFTS BACK WEST WITH THE APPROACH OF ANOTHER STRONG MID LEVEL WAVE EJECTING OUT OF THE CENTRAL PLAINS. YET AGAIN...A SEVERE THREAT WILL BE IN PLACE ON FRIDAY WITH GROWING CONCERNS OF MORE POTENTIAL FLOODING FROM THIS POINT ON...INTO FRIDAY NIGHT AND SATURDAY. THE SEVERE THREAT WILL LIKELY AFFECT THE ENTIRE CWA ON FRIDAY AND WITH CLEARING ANTICIPATED FRIDAY MORNING...INSTABILITY IS EXPECTED TO RAPIDLY INCREASE BY LATE MORNING WITH MODERATE TO STRONG INSTABILITY LIKELY IN PLACE ACROSS THE CWA. STRONG DEEP LAYER SHEAR IN UPWARDS OF 50-60KT WILL EASILY SUPPORT WIDESPREAD ORGANIZED DEVELOPMENT AS SOON AS EARLY AFTERNOON ON FRIDAY. STRONG DAMAGING WINDS AND HAIL ARE THE MAIN THREAT...BUT WITH SREF GUIDANCE INDICATING ELEMENTS CORRESPONDING TO SUPERCELLULAR STRUCTURES OR ROTATING THUNDERSTORMS COULD COME TOGETHER ACROSS THE CWA. WILL NEED TO CONTINUE TO MONITOR THIS TIME FRAME AS WELL...AS WIDESPREAD SEVERE IS APPEARING LIKELY ONCE AGAIN. GOING INTO FRIDAY NIGHT...HEAVY RAINFALL APPEARS LIKELY WITH SEVERAL STRONG WAVES PROPAGATING NORTHEAST ACROSS THE CWA PROVIDING CONTINUED DEVELOPMENT AS WELL AS A STRONG LLJ ORIENTED TOWARDS NORTHEAST ILLINOIS...PUMPING HIGH THETAE AIR INTO THE REGION. RODRIGUEZ EXTENDED...COMING SOON. && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND OVERNIGHT. * COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF AFTERNOON. * INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE SURFACE WIND GUSTS TO 50 KTS. ED F //DISCUSSION...UPDATED 18Z... AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS POSSIBLE AND GUSTY SOUTHERLY WINDS. SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG AS TODAY. SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA. WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY. THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH RESPECT TO PERIODIC CONVECTIVE CHANCES. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH GENERAL INCREASING TREND IN COVERAGE. * LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC TERMINALS. * MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE THIS EVENING. * MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE IN TIMING. * MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS. ED F //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... * FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA. POSSIBLE WITH MVFR CIGS/VIS. * SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR. * MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL. * LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA. KREIN && .MARINE... 1259 PM CDT THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS. ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF THE LAKE...AREAS OF DENSE FOG CONTINUE. VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE. FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS GENERALLY IN THE 15-25KT. THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY THAT IS IN EFFECT. THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY WITH MUCH COOLER AIR FLOWING OVER THE LAKE. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM SATURDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 7 AM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
322 PM CDT THU MAY 30 2013 .MESOSCALE DISCUSSION... 309 PM CDT SCATTERED THUNDERSTORMS CONTINUE TO FIRE ACROSS THE REGION. LACK OF LOW LEVEL CONVERGENCE AND ANY CONVECTIVE INHIBITION ALONG WITH INCREASING LARGE SCALE ASCENT AHEAD OF APPROACHING SHORT WAVE EVIDENT ON WATER VAPOR IMAGERY MOVING INTO WESTERN ILLINOIS SHOULD CONTINUE TO ALLOW THIS REGIME WITH STORMS GOING UP JUST ABOUT ANYWHERE. WIND PROFILERS SHOW A PRETTY TIGHT GRADIENT IN MID LEVEL FLOW WITH PROFILERS SHOWING 55-60KT WINDS AT 6KM OVER WESTERN ILLINOIS INTO IA/MO WITH ONLY ABOUT 40KT OF FLOW OVER OUR AREA. UNIDIRECTIONAL NATURE OF THE FLOW IS MINIMIZING DEEP LAYER SHEAR OVER OUR EASTERN CWA WITH ABOUT DEEP LAYER SHEAR ABOUT 20-30KT INCREASING TO AROUND 40KT WESTERN CWA. RAP SUGGESTS THAT THE STRONGER SHEAR WILL SPREAD EASTWARD ACROSS THE CWA THIS EVENING. LOW LEVEL SHEAR IS NOT OVERLY STRONG AT THIS TIME WITH WELL MIXED BOUNDARY LAYER...HOWEVER T/TD SPREADS ARE IN THE NEIGHBORHOOD OF 10-15F SO LCL HEIGHTS ARE NOT THAT HIGH SUGGESTING AT LEAST SOME LIMITED TORNADO THREAT FOR THE NEXT HOUR OR TWO. THIS WILL PARTICULARLY BE THE CASE WITH ANY CELLS THAT ARE ABLE TO ACHIEVE MORE DEVIANT RIGHTWARD MOTION AUGMENTING THE LOW LEVEL SHEAR. LOW LEVEL SHEAR SHOULD INCREASE THIS EVENING WITH DEVELOPMENT OF LOW LEVEL WIND MAXIMA...SO ASSUMING CONVECTION REMAINS CELLULAR AND ROOTED IN THE BOUNDARY LAYER THEN TORNADO THREAT COULD INCREASE SOME FOR A TIME EARLY THIS EVENING. IN THE NEXT HOUR OR TWO THINK THE PRIMARY HAZARD WILL BE DMG WIND AND HAIL...WITH A SLIGHT TORNADO THREAT MOSTLY OVER WESTERN CWA. IZZI && .DISCUSSION... 326 AM CDT CONVECTIVE TRENDS AND ASSOCIATED HEAVY RAIN AND SEVERE WEATHER THREAT REMAIN THE FOCUS OF THE FORECAST THIS PERIOD. UPPER AIR ANALYSIS AND EARLY MORNING WATER VAPOR IMAGERY SHOW A MUCH MORE AMPLIFIED PATTERN THAN LAST NIGHT WITH A BROAD RIDGE OVER THE EASTERN THIRD OR SO OF THE COUNTRY WITH A RIDGE AXIS EXTENDING FROM NORTHERN OHIO TO THE CANADIAN PRAIRIES. THE BASE OF A LONGWAVE TROUGH IS POSITIONED OVER THE FAR SOUTHERN PLAINS WITH THE AXIS EXTENDING NORTHWEST TO A CLOSED LOW SPINNING OFF THE BRITISH COLUMBIA COAST. SEVERAL SHORTWAVES ARE EMBEDDED WITHIN THE SOUTH-SOUTHWEST FLOW OVER THE CENTER OF THE COUNTRY. AT THE SURFACE...ONE LOW PRESSURE AREA IS POSITIONED OVER SOUTH DAKOTA WITH A SECOND OVER THE TX/OK PANHANDLE. A COLD FRONT IS STRETCHED BETWEEN THESE TWO LOWS WITH A WARM FRONTAL BOUNDARY FROM SOUTH DAKOTA ACROSS FAR NORTHERN LAKE MICHIGAN. TODAY THROUGH FRIDAY...AN UPPER LEVEL LOW WILL CLOSE OFF OVER THE WESTERN DAKOTAS TODAY AS THE MAIN LONGWAVE AXIS PIVOTS NORTHWARD ACROSS THE CENTRAL/SOUTHERN PLAINS AND MID MISSISSIPPI RIVER VALLEY. THIS WILL DEEPEN THE SURFACE LOW ACROSS THE DAKOTAS AND HELP PUSH THE ATTENDANT COLD FRONT INTO FAR WESTERN MINNESOTA AND IOWA BY EVENING. THERE ARE A RANGE OF POSSIBILITIES WITH REGARD TO CONVECTIVE EVOLUTION INTO TONIGHT GIVEN THE UPPER FLOW PATTERN AND PRESENCE OF NUMEROUS EMBEDDED WAVES. WATER VAPOR SHOWS THE LONGWAVE TROUGH AXIS PIVOTING NORTHEASTWARD ACROSS TX/OK AS IT IS BEING PUSHED BY A STRONG UPPER JET CORE ON ITS WESTERN FLANK. THE MAIN TROUGH ITSELF IS THE MOST COHERENT FOCUS FOR CONVECTIVE DEVELOPMENT...IN ADDITION TO THE NUMEROUS EMBEDDED WAVES. WITH THE STEERING FLOW PRETTY SELY THIS MORNING...THIS WILL INITIALLY KEEP ACTIVITY ON A TRAJECTORY WEST OF THE CWA BUT WITH THE MAIN LONGWAVE TROUGH SHIFTING EASTWARD AS AN UPPER JET MAX PUSHES IT FROM THE WEST THE MAIN CORRIDOR OF FLOW WILL TRANSLATE EASTWARD SPREADING CONVECTIVE CHANCES FURTHER INTO THE AREA. CHANCES FOR STORMS WILL THEREFORE INCREASE FROM WEST TO EAST THROUGH THE DAY...WITH MINIMAL CHANCES THROUGH LATE MORNING THOUGH THERE IS SUGGESTION OF SOME SCATTERED DEVELOPMENT THANKS TO A WEAK UPPER WAVE THAT AT THIS POINT IS NOT REALLY WELL DEFINED ON SATELLITE AND ONLY GENERATING CLOUD COVER WHICH IS MOVING NORTHWARD INTO SOUTHERN ILLINOIS. BEYOND THIS MORNING...TOUGH TO PINPOINT SPECIFIC CONVECTIVE EPISODES BUT IT APPEARS THAT ACTIVITY TO THE SOUTHWEST WILL SPREAD INTO THE CWA LATE THIS AFTERNOON OR EARLY THIS EVENING...THOUGH AGAIN...IT MAY BE PRECEDED BY LESS FOCUSED ACTIVITY. ADDITIONAL ROUNDS OF STORMS MAY CONTINUE THROUGH THE OVERNIGHT. BY FRIDAY MORNING...THE SURFACE AND UPPER LOWS WILL HAVE MOVED LITTLE BUT THE UPPER LOW WILL HAVE SEVERAL SPOKES OF ENERGY ROTATING AROUND IT. THERE IS GOOD MODEL AGREEMENT IN A SHORTWAVE DEVELOPING OVER THE CENTRAL/SOUTHERN ROCKIES EARLY FRIDAY THEN LIFTING NORTHEASTWARD DURING THE DAY AND BRINGING ANOTHER ROUND OF ORGANIZED STORMS EITHER LATE FRIDAY MORNING OR EARLY AFTERNOON. IN TERMS OF THREATS...PRECIPITABLE WATER VALUES OF AROUND 1.8 INCHES WILL SUPPORT A HEAVY RAIN THREAT TODAY AND TONIGHT WITH A BRIEF LOWERING OF VALUES FRIDAY MORNING AS DRIER MID LEVEL AIR WORKS IN BEHIND THE DEPARTING TROUGH. HOWEVER...ANOTHER PUSH OF HIGH PW AIR WILL ARRIVE WITH THE NEXT EXPECTED WAVE BY FRIDAY AFTERNOON. THE MAIN AREA OF CONCERN WILL BE THE WESTERN CWA GIVEN THAT THEY HAVE THE BEST CHANCE OF BEING AFFECTED BY MULTIPLE ROUNDS OF CONVECTION STARTING AS EARLY AS LATE THIS AFTERNOON. EACH OF THE WAVES SPAWNING THE CONVECTION WILL BE PROGRESSIVE WHICH LOOKS TO LIMIT THE DURATION OF HEAVY RAIN BUT 2 TO 3 INCHES BETWEEN NOW AND FRIDAY LOOKS REASONABLE ON THE LARGE SCALE THOUGH ISOLATED HIGHER AMOUNTS ARE CERTAINLY POSSIBLE. DECIDED TO GO WITH A FLASH FLOOD WATCH FOR LA SALLE AND LIVINGSTON COUNTIES GIVEN THE 4-5+ INCHES OF RAINFALL OBSERVED THERE OVER THE PAST FEW DAYS AND THE EXPECTED RAINFALL ABOVE. AREAS TO THE NORTH HAVE SEEN FAR LESS RAINFALL SO POTENTIAL IS LESS CERTAIN THERE AND 1 AND 3 HR FLASH FLOOD GUIDANCE VALUES ARE 1.6 AND 1.9 INCHES RESPECTIVELY AND HIGHER. AREAS TO THE EAST ALONG THE I-80 CORRIDOR HAVE ALSO SEEN SIGNIFICANT RAINFALL THE PAST FEW DAYS BUT STILL HAVE QUESTIONS HOW FAR EAST THE HEAVIEST RAINFALL WILL STRETCH AND ALSO EXPECT A BIT LATER START TO THE BEST ORGANIZED CONVECTION THERE. AN EXPANSION IS POSSIBLE HOWEVER. IN TERMS OF THE SEVERE THREAT...STORMS THAT CAN DEVELOP PRIOR TO MID AFTERNOON WILL HAVE SOME SEVERE THREAT WITH DECENT INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZATION. AGAIN...THE FORCING DURING THIS PERIOD IS SUBTLE AT BEST AT THIS POINT AND THERE IS SOME MINIMAL CAPPING...SO FEEL CHANCES ARE PRETTY LOW. ONCE EVENING ARRIVES...THE ODDS ARE BETTER THAT AN ORGANIZED CONVECTIVE COMPLEX OR COMPLEXES WILL MOVE IN. HEAVY RAIN AND DAMAGING WINDS WILL BE THE MAIN THREATS. SOME OF THE SEVERE THREAT MAY BE CONDITIONAL BASED ON HOW THINGS DEVELOP UPSTREAM AND IF ANY LATE MORNING/EARLY AFTERNOON CONVECTION CAN DEVELOP. SEVERE POTENTIAL MAY BE HIGHER FRIDAY DEPENDING ON CONVECTIVE DEBRIS...BUT LOW LEVEL WIND FIELDS STRENGTHEN WITH GREATER DEEP LAYER SHEAR AS WELL SO BETTER STORM ORGANIZATION IS POSSIBLE. DAMAGING WIND/HAIL/ISOLATED TORNADO THREATS MAY BE HIGHER. WARM AND MUGGY CONDITIONS WILL CONTINUE. HIGHS TODAY WILL BE TOUGH WITH A BREEZY SOUTH-SOUTHWEST WIND POINTING TOWARD WARMER READINGS BUT APPROACHING CLOUD COVER ARGUING AGAINST. WILL CONTINUE WITH MID 80S WITH SOME POTENTIAL FOR HIGHER VALUES IF CLOUD COVER IS LESS THAN EXPECTED. FRIDAY SHOULD BE SLIGHTLY COOLER WITH MORE CLOUDS AND HIGHER DAYTIME PRECIP CHANCES. SATURDAY THROUGH MID WEEK...AN UPPER TROUGH WILL MOVE SOUTHEAST ACROSS NORTHERN ALBERTA/SASKATCHEWAN FRIDAY NIGHT AND PHASE WITH THE CLOSED UPPER LOW OVER THE DAKOTAS. THIS WILL ALLOW THE LOW TO OPEN UP AND THEN SWING SOUTHEASTWARD. IN TURN...THE SURFACE LOW WILL BE KICKED EASTWARD AS WELL PUSHING THE COLD FRONT INTO THE AREA SATURDAY. THIS WILL TRIGGER ADDITIONAL CHANCES FOR CONVECTION...ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST AREA SATURDAY AFTERNOON AND EVENING. THE UPPER TROUGH CROSSES THE AREA SATURDAY EVENING THOUGH CYCLONIC UPPER FLOW WILL CONTINUE THROUGH SUNDAY. MUCH COOLER AIR WILL FLOW IN FROM THE NORTH WITH H85 TEMPS FALLING FROM AROUND +16 TO +4 BY SUNDAY EVENING. SHOWER/ISOLD THUNDER CHANCES WILL LINGER SUNDAY WITH THE CYCLONIC FLOW. HIGH PRESSURE WILL SPREAD SOUTHWARD INTO THE PLAINS WHICH WILL PROVIDE QUIET WEATHER MONDAY. MODEL GUIDANCE DIVERGES TUESDAY WITH HOW THE UPPER FLOW PATTERN EVOLVES THOUGH IT DOES APPEAR THAT AT LEAST WEAK UPPER RIDGING WILL MOVE ACROSS TUESDAY BRINGING WARMER MID LEVEL AIR BUT TROUGHING RETURNS BY MID WEEK. PRECIP CHANCES MAY RETURN AS EARLY AS TUESDAY EVENING DEPENDING ON HOW THE FLOW PATTERN PANS OUT BUT GIVEN THE POTENTIAL FOR WAA TO BUILD AHEAD OF THE RIDGE OR AN ACTIVE ZONAL PATTERN IF THE RIDGE IS WEAKER...SOME PRECIP IS POSSIBLE. TEMPS WILL BE COOLER SUNDAY WITH HIGHS IN THE MID 60S NORTH TO AROUND 70 SOUTH WITH MONDAY AND TUESDAY EACH BEING WARMER THAN THE DAY BEFORE. FLOW OFF THE LAKE SUNDAY THROUGH TUESDAY WILL KEEP LAKESHORE READINGS COOLER AND LAKE BREEZE DEVELOPMENT MAY PROPEL COOLER TEMPS FURTHER INLAND EACH AFTERNOON. MDB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * ONGOING SCATTERED CONVECTION CONTINUING THROUGH THE EVENING AND OVERNIGHT. * COVERAGE OF TSTMS GRADUALLY INCREASING THROUGH REMAINDER OF AFTERNOON. * INDIVIDUAL STORMS PULSING UP AND DOWN HAVE POTENTIAL TO PRODUCE SURFACE WIND GUSTS TO 50 KTS. ED F //DISCUSSION...UPDATED 18Z... AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS POSSIBLE AND GUSTY SOUTHERLY WINDS. SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG AS TODAY. SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA. WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY. THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH RESPECT TO PERIODIC CONVECTIVE CHANCES. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN TSTMS CONTINUING THROUGH THE EVENING WITH GENERAL INCREASING TREND IN COVERAGE. * LOW CONFIDENCE IN TIMING OF ANY SPECIFIC TSTM CELLS AT SPECIFIC TERMINALS. * MEDIUM CONFIDENCE IN LINE OF TSTMS IMPACTING TERMINALS LATE THIS EVENING. * MEDIUM CONFIDENCE IN ADDITIONAL TSTMS FRIDAY...LOW CONFIDENCE IN TIMING. * MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS. ED F //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... * FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA. POSSIBLE WITH MVFR CIGS/VIS. * SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR. * MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL. * LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA. KREIN && .MARINE... 1259 PM CDT THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS. ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF THE LAKE...AREAS OF DENSE FOG CONTINUE. VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE. FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS GENERALLY IN THE 15-25KT. THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY THAT IS IN EFFECT. THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY WITH MUCH COOLER AIR FLOWING OVER THE LAKE. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM SATURDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 7 AM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
309 PM CDT THU MAY 30 2013 .MESOSCALE DISCUSSION... 309 PM CDT SCATTERED THUNDERSTORMS CONTINUE TO FIRE ACROSS THE REGION. LACK OF LOW LEVEL CONVERGENCE AND ANY CONVECTIVE INHIBITION ALONG WITH INCREASING LARGE SCALE ASCENT AHEAD OF APPROACHING SHORT WAVE EVIDENT ON WATER VAPOR IMAGERY MOVING INTO WESTERN ILLINOIS SHOULD CONTINUE TO ALLOW THIS REGIME WITH STORMS GOING UP JUST ABOUT ANYWHERE. WIND PROFILERS SHOW A PRETTY TIGHT GRADIENT IN MID LEVEL FLOW WITH PROFILERS SHOWING 55-60KT WINDS AT 6KM OVER WESTERN ILLINOIS INTO IA/MO WITH ONLY ABOUT 40KT OF FLOW OVER OUR AREA. UNIDIRECTIONAL NATURE OF THE FLOW IS MINIMIZING DEEP LAYER SHEAR OVER OUR EASTERN CWA WITH ABOUT DEEP LAYER SHEAR ABOUT 20-30KT INCREASING TO AROUND 40KT WESTERN CWA. RAP SUGGESTS THAT THE STRONGER SHEAR WILL SPREAD EASTWARD ACROSS THE CWA THIS EVENING. LOW LEVEL SHEAR IS NOT OVERLY STRONG AT THIS TIME WITH WELL MIXED BOUNDARY LAYER...HOWEVER T/TD SPREADS ARE IN THE NEIGHBORHOOD OF 10-15F SO LCL HEIGHTS ARE NOT THAT HIGH SUGGESTING AT LEAST SOME LIMITED TORNADO THREAT FOR THE NEXT HOUR OR TWO. THIS WILL PARTICULARLY BE THE CASE WITH ANY CELLS THAT ARE ABLE TO ACHEIVE MORE DEVIANT RIGHTWARD MOTION AUGMENTING THE LOW LEVEL SHEAR. LOW LEVEL SHEAR SHOULD INCREASE THIS EVENING WITH DEVELOPMENT OF LOW LEVEL WIND MAXIMA...SO ASSUMING CONVECTION REMAINS CELLULAR AND ROOTED IN THE BOUNDARY LAYER THEN TORNADO THREAT COULD INCREASE SOME FOR A TIME EARLY THIS EVENING. IN THE NEXT HOUR OR TWO THINK THE PRIMARY HAZARD WILL BE DMG WIND AND HAIL...WITH A SLIGHT TORNADO THREAT MOSTLY OVER WESTERN CWA. IZZI && .DISCUSSION... 326 AM CDT CONVECTIVE TRENDS AND ASSOCIATED HEAVY RAIN AND SEVERE WEATHER THREAT REMAIN THE FOCUS OF THE FORECAST THIS PERIOD. UPPER AIR ANALYSIS AND EARLY MORNING WATER VAPOR IMAGERY SHOW A MUCH MORE AMPLIFIED PATTERN THAN LAST NIGHT WITH A BROAD RIDGE OVER THE EASTERN THIRD OR SO OF THE COUNTRY WITH A RIDGE AXIS EXTENDING FROM NORTHERN OHIO TO THE CANADIAN PRAIRIES. THE BASE OF A LONGWAVE TROUGH IS POSITIONED OVER THE FAR SOUTHERN PLAINS WITH THE AXIS EXTENDING NORTHWEST TO A CLOSED LOW SPINNING OFF THE BRITISH COLUMBIA COAST. SEVERAL SHORTWAVES ARE EMBEDDED WITHIN THE SOUTH-SOUTHWEST FLOW OVER THE CENTER OF THE COUNTRY. AT THE SURFACE...ONE LOW PRESSURE AREA IS POSITIONED OVER SOUTH DAKOTA WITH A SECOND OVER THE TX/OK PANHANDLE. A COLD FRONT IS STRETCHED BETWEEN THESE TWO LOWS WITH A WARM FRONTAL BOUNDARY FROM SOUTH DAKOTA ACROSS FAR NORTHERN LAKE MICHIGAN. TODAY THROUGH FRIDAY...AN UPPER LEVEL LOW WILL CLOSE OFF OVER THE WESTERN DAKOTAS TODAY AS THE MAIN LONGWAVE AXIS PIVOTS NORTHWARD ACROSS THE CENTRAL/SOUTHERN PLAINS AND MID MISSISSIPPI RIVER VALLEY. THIS WILL DEEPEN THE SURFACE LOW ACROSS THE DAKOTAS AND HELP PUSH THE ATTENDANT COLD FRONT INTO FAR WESTERN MINNESOTA AND IOWA BY EVENING. THERE ARE A RANGE OF POSSIBILITIES WITH REGARD TO CONVECTIVE EVOLUTION INTO TONIGHT GIVEN THE UPPER FLOW PATTERN AND PRESENCE OF NUMEROUS EMBEDDED WAVES. WATER VAPOR SHOWS THE LONGWAVE TROUGH AXIS PIVOTING NORTHEASTWARD ACROSS TX/OK AS IT IS BEING PUSHED BY A STRONG UPPER JET CORE ON ITS WESTERN FLANK. THE MAIN TROUGH ITSELF IS THE MOST COHERENT FOCUS FOR CONVECTIVE DEVELOPMENT...IN ADDITION TO THE NUMEROUS EMBEDDED WAVES. WITH THE STEERING FLOW PRETTY SELY THIS MORNING...THIS WILL INITIALLY KEEP ACTIVITY ON A TRAJECTORY WEST OF THE CWA BUT WITH THE MAIN LONGWAVE TROUGH SHIFTING EASTWARD AS AN UPPER JET MAX PUSHES IT FROM THE WEST THE MAIN CORRIDOR OF FLOW WILL TRANSLATE EASTWARD SPREADING CONVECTIVE CHANCES FURTHER INTO THE AREA. CHANCES FOR STORMS WILL THEREFORE INCREASE FROM WEST TO EAST THROUGH THE DAY...WITH MINIMAL CHANCES THROUGH LATE MORNING THOUGH THERE IS SUGGESTION OF SOME SCATTERED DEVELOPMENT THANKS TO A WEAK UPPER WAVE THAT AT THIS POINT IS NOT REALLY WELL DEFINED ON SATELLITE AND ONLY GENERATING CLOUD COVER WHICH IS MOVING NORTHWARD INTO SOUTHERN ILLINOIS. BEYOND THIS MORNING...TOUGH TO PINPOINT SPECIFIC CONVECTIVE EPISODES BUT IT APPEARS THAT ACTIVITY TO THE SOUTHWEST WILL SPREAD INTO THE CWA LATE THIS AFTERNOON OR EARLY THIS EVENING...THOUGH AGAIN...IT MAY BE PRECEDED BY LESS FOCUSED ACTIVITY. ADDITIONAL ROUNDS OF STORMS MAY CONTINUE THROUGH THE OVERNIGHT. BY FRIDAY MORNING...THE SURFACE AND UPPER LOWS WILL HAVE MOVED LITTLE BUT THE UPPER LOW WILL HAVE SEVERAL SPOKES OF ENERGY ROTATING AROUND IT. THERE IS GOOD MODEL AGREEMENT IN A SHORTWAVE DEVELOPING OVER THE CENTRAL/SOUTHERN ROCKIES EARLY FRIDAY THEN LIFTING NORTHEASTWARD DURING THE DAY AND BRINGING ANOTHER ROUND OF ORGANIZED STORMS EITHER LATE FRIDAY MORNING OR EARLY AFTERNOON. IN TERMS OF THREATS...PRECIPITABLE WATER VALUES OF AROUND 1.8 INCHES WILL SUPPORT A HEAVY RAIN THREAT TODAY AND TONIGHT WITH A BRIEF LOWERING OF VALUES FRIDAY MORNING AS DRIER MID LEVEL AIR WORKS IN BEHIND THE DEPARTING TROUGH. HOWEVER...ANOTHER PUSH OF HIGH PW AIR WILL ARRIVE WITH THE NEXT EXPECTED WAVE BY FRIDAY AFTERNOON. THE MAIN AREA OF CONCERN WILL BE THE WESTERN CWA GIVEN THAT THEY HAVE THE BEST CHANCE OF BEING AFFECTED BY MULTIPLE ROUNDS OF CONVECTION STARTING AS EARLY AS LATE THIS AFTERNOON. EACH OF THE WAVES SPAWNING THE CONVECTION WILL BE PROGRESSIVE WHICH LOOKS TO LIMIT THE DURATION OF HEAVY RAIN BUT 2 TO 3 INCHES BETWEEN NOW AND FRIDAY LOOKS REASONABLE ON THE LARGE SCALE THOUGH ISOLATED HIGHER AMOUNTS ARE CERTAINLY POSSIBLE. DECIDED TO GO WITH A FLASH FLOOD WATCH FOR LA SALLE AND LIVINGSTON COUNTIES GIVEN THE 4-5+ INCHES OF RAINFALL OBSERVED THERE OVER THE PAST FEW DAYS AND THE EXPECTED RAINFALL ABOVE. AREAS TO THE NORTH HAVE SEEN FAR LESS RAINFALL SO POTENTIAL IS LESS CERTAIN THERE AND 1 AND 3 HR FLASH FLOOD GUIDANCE VALUES ARE 1.6 AND 1.9 INCHES RESPECITVELY AND HIGHER. AREAS TO THE EAST ALONG THE I-80 CORRIDOR HAVE ALSO SEEN SIGNIFICANT RAINFALL THE PAST FEW DAYS BUT STILL HAVE QUESTIONS HOW FAR EAST THE HEAVIEST RAINFALL WILL STRETCH AND ALSO EXPECT A BIT LATER START TO THE BEST ORGANIZED CONVECTION THERE. AN EXPANSION IS POSSIBLE HOWEVER. IN TERMS OF THE SEVERE THREAT...STORMS THAT CAN DEVELOP PRIOR TO MID AFTERNOON WILL HAVE SOME SEVERE THREAT WITH DECENT INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZATION. AGAIN...THE FORCING DURING THIS PERIOD IS SUBTLE AT BEST AT THIS POINT AND THERE IS SOME MINIMAL CAPPING...SO FEEL CHANCES ARE PRETTY LOW. ONCE EVENING ARRIVES...THE ODDS ARE BETTER THAT AN ORGANIZED CONVECTIVE COMPLEX OR COMPLEXES WILL MOVE IN. HEAVY RAIN AND DAMAGING WINDS WILL BE THE MAIN THREATS. SOME OF THE SEVERE THREAT MAY BE CONDITIONAL BASED ON HOW THINGS DEVELOP UPSTREAM AND IF ANY LATE MORNING/EARLY AFTERNOON CONVECTION CAN DEVELOP. SEVERE POTENTIAL MAY BE HIGHER FRIDAY DEPENDING ON CONVECTIVE DEBRIS...BUT LOW LEVEL WIND FIELDS STRENGTHEN WITH GREATER DEEP LAYER SHEAR AS WELL SO BETTER STORM ORGANIZATION IS POSSIBLE. DAMAGING WIND/HAIL/ISOLATED TORNADO THREATS MAY BE HIGHER. WARM AND MUGGY CONDITIONS WILL CONTINUE. HIGHS TODAY WILL BE TOUGH WITH A BREEZY SOUTH-SOUTHWEST WIND POINTING TOWARD WARMER READINGS BUT APPROACHING CLOUD COVER ARGUING AGAINST. WILL CONTINUE WITH MID 80S WITH SOME POTENTIAL FOR HIGHER VALUES IF CLOUD COVER IS LESS THAN EXPECTED. FRIDAY SHOULD BE SLIGHTLY COOLER WITH MORE CLOUDS AND HIGHER DAYTIME PRECIP CHANCES. SATURDAY THROUGH MID WEEK...AN UPPER TROUGH WILL MOVE SOUTHEAST ACROSS NORTHERN ALBERTA/SASKATCHEWAN FRIDAY NIGHT AND PHASE WITH THE CLOSED UPPER LOW OVER THE DAKOTAS. THIS WILL ALLOW THE LOW TO OPEN UP AND THEN SWING SOUTHEASTWARD. IN TURN...THE SURFACE LOW WILL BE KICKED EASTWARD AS WELL PUSHING THE COLD FRONT INTO THE AREA SATURDAY. THIS WILL TRIGGER ADDITIONAL CHANCES FOR CONVECTION...ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST AREA SATURDAY AFTERNOON AND EVENING. THE UPPER TROUGH CROSSES THE AREA SATURDAY EVENING THOUGH CYCLONIC UPPER FLOW WILL CONTINUE THROUGH SUNDAY. MUCH COOLER AIR WILL FLOW IN FROM THE NORTH WITH H85 TEMPS FALLING FROM AROUND +16 TO +4 BY SUNDAY EVENING. SHOWER/ISOLD THUNDER CHANCES WILL LINGER SUNDAY WITH THE CYCLONIC FLOW. HIGH PRESSURE WILL SPREAD SOUTHWARD INTO THE PLAINS WHICH WILL PROVIDE QUIET WEATHER MONDAY. MODEL GUIDANCE DIVERGES TUESDAY WITH HOW THE UPPER FLOW PATTERN EVOLVES THOUGH IT DOES APPEAR THAT AT LEAST WEAK UPPER RIDGING WILL MOVE ACROSS TUESDAY BRINGING WARMER MID LEVEL AIR BUT TROUGHING RETURNS BY MID WEEK. PRECIP CHANCES MAY RETURN AS EARLY AS TUESDAY EVENING DEPENDING ON HOW THE FLOW PATTERN PANS OUT BUT GIVEN THE POTENTIAL FOR WAA TO BUILD AHEAD OF THE RIDGE OR AN ACTIVE ZONAL PATTERN IF THE RIDGE IS WEAKER...SOME PRECIP IS POSSIBLE. TEMPS WILL BE COOLER SUNDAY WITH HIGHS IN THE MID 60S NORTH TO AROUND 70 SOUTH WITH MONDAY AND TUESDAY EACH BEING WARMER THAN THE DAY BEFORE. FLOW OFF THE LAKE SUNDAY THROUGH TUESDAY WILL KEEP LAKESHORE READINGS COOLER AND LAKE BREEZE DEVELOPMENT MAY PROPEL COOLER TEMPS FURTHER INLAND EACH AFTERNOON. MDB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SEVERAL ROUNDS OF THUNDERSTORMS POSSIBLE. * GUSTY SOUTHERLY WINDS. BMD //DISCUSSION...UPDATED 18Z... AN ACTIVE PERIOD IS EXPECTED WITH SEVERAL BOUTS OF THUNDERSTORMS POSSIBLE AND GUSTY SOUTHERLY WINDS. SYNOPTICALLY...AREA OF LOW PRESSURE LIES OVER THE NORTHERN PLAIN AND WILL GRADUALLY SHIFT NORTHEAST THROUGH THE TAF PERIOD. NORTHERN ILLINOIS LIES IN A TIGHT SOUTHERLY GRADIENT WITH WINDS GUSTING TO AROUND 30 KT ALREADY EARLY THIS AFTERNOON AND EXPECTED TO PERSIST THROUGH THE DAY. WINDS MAY TAPER SOME WITH SUNSET...THEN ARE EXPECTED TO BECOME GUSTY AGAIN FRIDAY...THOUGH NOT QUITE AS STRONG AS TODAY. SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE...WITH THE DETAILS STILL A BIT MURKY. FIRST ROUND IS ALREADY STARTING TO TAKE SHAPE THIS AFTERNOON AS STRONG INSTABILITY HAS DEVELOPED OVER THE AREA WITH CONVECTION ALREADY DEVELOPING DOWNSTATE AHEAD OF A NEGATIVELY TILTED TROUGH LIFTING ACROSS THE MID MISSISSIPPI VALLEY. THIS WAVE WILL CONTINUE NORTHEAST INTO NORTHERN ILLINOIS MID AFTERNOON WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS EXPECTED OVER THE AREA. WITH NO SIGNIFICANT LOW LEVEL BOUNDARIES OR FOCUSING MECHANISMS...IT WILL BE HARD TO IMPOSSIBLE TO PINPOINT EXACTLY WHERE THUNDERSTORMS WILL DEVELOP...THOUGH THE BEST INSTABILITY HAS SET UP JUST WEST OF THE CHICAGO TERMINALS. THEN THIS EVENING...NUMEROUS CONVECTIVE ALLOWING MODELS ARE INDICATING THAT A SECOND ROUND OF CONVECTION WILL CONGEAL INTO A LINE OFF TO OUR WEST WITH THE DEVELOPMENT OF A MODERATE TO STRONG LOW LEVEL JET ALONG THE MISSISSIPPI RIVER VALLEY. THIS LINE IS EXPECTED TO RACE EAST LATE THIS EVENING OR EARLY OVERNIGHT. FINALLY...WITH SIMILAR CONDITIONS IN PLACE TOMORROW...WILL BE LOOKING AT MUCH OF THE SAME CONCERNS FRIDAY WITH RESPECT TO PERIODIC CONVECTIVE CHANCES. BMD //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE IN TSTRMS THIS AFTERNOON...LOW CONFIDENCE IN DIRECT IMPACTS TO TERMINALS DUE TO SCATTERED COVERAGE. * MEDIUM CONFIDENCE IN LINE OF TSTRMS IMPACTING TERMINALS LATE THIS EVENING. * MEDIUM CONFIDENCE IN ADDITIONAL TSTRMS FRIDAY...LOW CONFIDENCE IN TIMING. * MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS. BMD //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... * FRIDAY THROUGH SATURDAY...PERIODS OF TSRA/SHRA. POSSIBLE WITH MVFR CIGS/VIS. * SUNDAY...CHANCE OF SHRA EARLY...OTRW...VFR. * MONDAY THROUGH EARLY TUESDAY...VFR. WX NIL. * LATE TUESDAY THROUGH WEDNESDAY...CHANCE TSRA/SHRA. KREIN && .MARINE... 1259 PM CDT THE SHORT TERM OF THE MARINE FORECAST HAS A SMALL CRAFT ADVISORY FOR STRONG WINDS ACROSS THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS. ACROSS THE OPEN WATERS OF THE LAKE...MAINLY THE NORTHERN THIRD OF THE LAKE...AREAS OF DENSE FOG CONTINUE. VERY WARM/MOIST AIR CONTINUES TO SLIDE NORTH ACROSS THE LAKE...AND WITH THE MUCH COOLER LAKE SURFACE WATER...HAS RESULTED IN AREAS OF DENSE FOG PERSISTING. IT DOES APPEAR BASED ON LATEST VISIBLE IMAGERY THAT THE FOG HAS REMAINED FOCUSED ACROSS THE NORTHERN THIRD OF THE LAKE. OBS HAVE CONTINUED TO SHOW INCREASING GUSTS...WITH SPEEDS GENERALLY AROUND 20-25KT ACROSS THE SOUTHERN HALF OF THE LAKE. FURTHER NORTH IT APPEARS THE WINDS ARE SLIGHTLY LESS...WITH SPEEDS GENERALLY IN THE 15-25KT. THE TROUGH OF LOW PRESSURE REMAINS CENTERED ACROSS THE CENTRAL PLAINS...WITH A WEAK LOW PRESSURE LIFTING NORTH INTO THE NORTHERN PLAINS. AN ASSOCIATED WARM FRONT EXTENDS EAST THROUGH THE UPPER GREAT LAKES REGION. WITH THE POSITION OF THE LOW PRESSURE AND THE PERSISTING RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN UNITED STATES...THE WIND FLOW WILL REMAIN SOUTHERLY ACROSS THE LAKE. AT TIMES THROUGH EARLY THIS EVENING GUSTS MAY APPROACH 30 KT...MAINLY FOR THE SOUTHERN PORTIONS OF THE LAKE INCLUDING THE NEARSHORE WATERS. AS A RESULT WILL MAINTAIN THE CURRENT SMALL CRAFT ADVISORY THAT IS IN EFFECT. THE TROUGH OF LOW PRESSURE POSITIONED OVER THE CENTRAL PLAINS WILL SLOWLY PUSH EAST...WITH A LOW PRESSURE APPROACHING THE WESTERN GREAT LAKES SAT MIDDAY. THE RECENT FORECAST TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THIS SYSTEM...THUS IT IS POSSIBLE THAT THE MAIN LOW PRESSURE MAY NOT ARRIVE UNTIL CLOSER TO SAT NIGHT. THEN AN ASSOCIATED COLD FRONT WILL WILL PUSH EAST ACROSS THE LAKE OVERNIGHT SAT INTO SUN. WINDS AT THAT POINT WILL TURN WESTERLY THEN NORTHERLY WITH MUCH COOLER AIR FLOWING OVER THE LAKE. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ019-ILZ032...7 PM THURSDAY TO 7 PM SATURDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 7 AM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 PM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1259 PM CDT THU MAY 30 2013 .DISCUSSION... ISSUED 1030 AM CDT THU MAY 30 2013 MORNING SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED ALONG THE EAST COAST AND LOW PRESSURE CENTERED OVER SOUTH DAKOTA. THE PRESSURE GRADIENT BETWEEN THESE TWO FEATURES IS CREATING STRONG/GUSTY SOUTHERLY WINDS ACROSS CENTRAL ILLINOIS...WITH THE 15Z/10AM OBS INDICATING GUSTS ALREADY EXCEEDING 30 MPH IN A FEW LOCATIONS. RADAR MOSAIC HAS BEEN FAIRLY QUIET SO FAR...WITH ONLY A FEW ISOLATED SHOWERS ACROSS EAST-CENTRAL ILLINOIS EARLIER THIS MORNING. DESPITE RATHER BULLISH PRECIP DEVELOPMENT IN THE WARM SECTOR AS ADVERTISED BY THE 12Z NAM...THINK ONLY ISOLATED SHOWERS/THUNDER WILL OCCUR ACROSS THE AREA THROUGH EARLY AFTERNOON. AS ATMOSPHERE DESTABILIZES...SCATTERED SHOWERS/STORMS WILL DEVELOP BY MID TO LATE AFTERNOON. LATEST HRRR SUGGESTS THE MOST WIDESPREAD CONVECTION WILL REMAIN WEST OF THE MISSISSIPPI RIVER UNTIL THIS EVENING WHEN STORMS TRACK INTO AT LEAST THE WESTERN HALF OF THE KILX CWA. HAVE UPDATED FORECAST TO LOWER POPS THIS MORNING...FEATURING ONLY ISOLATED SHOWERS THROUGH EARLY AFTERNOON. WILL GO WITH SCATTERED WORDING THIS AFTERNOON...THEN WILL HIT POPS HARD TONIGHT WHEN BETTER FORCING APPROACHES FROM THE WEST. ZONE UPDATE HAS ALREADY BEEN ISSUED. && .AVIATION... ISSUED 1258 PM CDT THU MAY 30 2013 SCATTERED CONVECTION WILL CONTINUE TO DEVELOP WITHIN THE WARM SECTOR ACROSS CENTRAL ILLINOIS THIS AFTERNOON. THE STORMS WILL TRACK FROM SOUTH TO NORTH ACROSS THE AREA...PRIMARILY IMPACTING LOCATIONS WEST OF I-57. BASED ON LATEST RADAR DATA...HAVE INCLUDED A TEMPO GROUP FOR THUNDER AT ALL TAF SITES EXCEPT KCMI. WILL NEED TO MONITOR LARGER COMPLEX OF STORMS DEVELOPING FURTHER WEST OVER THE CENTRAL PLAINS AS IT MAY WORK ITS WAY EASTWARD INTO THE AREA TONIGHT. AT THIS TIME...WILL FOCUS ON THE IMMEDIATE CONVECTION THIS AFTERNOON/EARLY EVENING AND KEEP OVERNIGHT FORECAST DRY UNTIL TRENDS BECOME MORE APPARENT. WINDS WILL BE STRONG/GUSTY THROUGH THE PERIOD. GUSTS WILL FREQUENTLY EXCEED 30KT THIS AFTERNOON...THEN WINDS WILL DIMINISH TO BETWEEN 10 AND 15KT LATE TONIGHT INTO FRIDAY MORNING. BARNES && .PREV DISCUSSION... ISSUED 316 AM CDT THU MAY 30 2013 SHORT TERM...TODAY THROUGH SATURDAY 07Z SURFACE MAP SHOWED DOUBLE-BARREL LOW PRESSURE OVER THE PLAINS WITH ONE LOW CENTER IN CENTRAL SD AND A SOUTHERN LOW NEAR THE OK/TX PANHANDLE. TIGHTENING MSLP GRADIENT BETWEEN THIS AND SFC HIGH ALONG THE EAST COAST CAUSED 10-20 MPH S/SE WINDS OVERNIGHT...KEEPING DEWPOINTS UP IN THE MID 60S AND EARLY MORNING TEMPS IN THE UPPER 60S TO LOWER 70S. NEGATIVELY TILTED MID LEVEL TROF WAS LIFTING INTO THE WESTERN HIGH PLAINS RESPONSIBLE FOR LARGE AREA OF CONVECTION FROM THE PLAINS INTO THE UPPER MIDWEST. WATER VAPOR IMAGERY INDICATED A WEAK WAVE AND MID LEVEL MOISTURE POOL TRACKING NORTH FROM THE LOWER MS VALLEY...ON THE BACK SIDE OF THE SUB-TROPICAL RIDGE CENTERED OFF THE EAST COAST. SHORT RANGE HI-RES MODELS DEVELOP CONVECTION WITH THIS FEATURE AS IT SHIFTS NE INTO THE LOWER OHIO VALLEY THIS MORNING...AND LATEST RADAR MOSAIC INDICATED A SHOWER IN EAST CENTRAL IL AND A FEW MORE IN SE MO. THUS MAY SEE A SLIGHTLY MORE FOCUSED AREA OF SCATTERED SHOWERS/STORMS EAST OF I-57 INTO MID MORNING. OTHERWISE DEEPER CONVECTION IS EXPECTED TO DEVELOP OVER MISSOURI AND IOWA THIS AFTERNOON ASSOCIATED WITH A SIGNIFICANT SHORTWAVE EJECTING OUT OF THE WESTERN TROF. CONVECTIVE MODELS SHOW THIS ENTERING THE WESTERN CWA LATER THIS AFTERNOON AND EVENING...IN A WEAKENING FASHION AS LESS INSTABILITY IS INDICATED EAST OF THE MS RIVER. MOIST PROFILES ALSO SUGGEST A LOWER SVR THREAT...HOWEVER WITH DECENT WIND FIELDS ALOFT WOULD NOT BE SURPRISED TO SEE SOME STRONG OR NEAR SVR STORMS. ASIDE FROM POSSIBLE CONVECTION...ANOTHER ISSUE WILL BRISK AND GUSTY SOUTH WINDS IN TIGHT GRADIENT. BUFKIT DATA SHOWS GUSTS OVER 30 KTS DURING PEAK HEATING BUT CLOUD COVER COULD TEMPER HIGHER GUSTS. FAIRLY STRONG MODEL SIGNALS THAT AN MCS WILL FORM OVER KS/MO TONIGHT AND LIFT NORTHEAST INTO THE CWA ON FRIDAY. THIS SHOULD BE MAINTAINED BY A VIGOROUS 40-60 KT LLJ AND COULD BRING ANOTHER ROUND OF HEAVY RAIN TO THE NW CWA INTO MIDDAY. THE EFFECTS OF THIS MCS WILL IMPACT CONVECTIVE DEVELOPMENT LATER IN THE DAY AND IF ATMOSPHERE CAN RECOVER THEN STRONG STORMS MAY REDEVELOP ALONG THE LINGERING OUTFLOW BOUNDARY. BETTER WIND FIELDS ALOFT ASSOCIATED WITH THE APPROACHING UPPER TROF WILL CONTRIBUTE TO HIGHER BULK SHEAR AND THE POTENTIAL FOR MORE ORGANIZED SEVERE WEATHER. AS THE UPPER TROF STEADILY SHIFTS EAST...IT WILL DRIVE A COLD FRONT INTO THE STATE ON SATURDAY. FRONTAL TIMING WILL BE CRITICAL FOR ANOTHER ROUND OF POSSIBLE SEVERE STORMS AND HEAVY RAIN...AND 00Z MODELS ARE A FEW HOURS QUICKER WITH THE FRONT THAT PREVIOUS RUNS. THIS WOULD FAVOR BEST CHANCE OF REDEVELOPMENT ALONG THE FRONT OR PRE-FRONTAL TROF FOR THE CENTRAL OR EASTERN CWA SATURDAY AFTERNOON INTO EVENING. WITH THE THREAT FOR HEAVY RAIN STARTING LATER THIS AFTERNOON ACROSS THE WEST...AND CONTINUING UNTIL THE COLD FRONTAL PASSAGE SATURDAY HAVE DECIDED TO GO WITH ANOTHER FLASH FLOOD WATCH ALONG/WEST OF I-55. THIS WILL BE IN EFFECT THIS AFTERNOON THROUGH SATURDAY AFTERNOON. SEE HYDROLOGY SECTION BELOW FOR MORE INFO ON HEAVY RAIN/FLOOD POTENTIAL. LONG TERM...SUNDAY THROUGH WEDNESDAY THE POST-FRONTAL AIRMASS WILL BRING A RETURN TO MUCH COOLER AND DRIER WEATHER FOR THE LAST HALF OF THE WEEKEND. A DEEP TROF IS FORECAST TO ROTATE SOUTH INTO THE NORTHERN GREAT LAKES BY LATE SUNDAY WITH A CHILLY...FOR EARLY SUMMER...-24C 500 MB AIRMASS. CANADIAN HIGH PRESSURE AT THE SURFACE WILL BUILD INTO THE GREAT LAKES BY EARLY NEXT WEEK...AND CONTINUE TO PROVIDE A COOL NORTHERLY FLOW TO CENTRAL IL. THUS TEMPERATURES ARE EXPECTED TO BE SEVERAL DEGREES BELOW NORMAL INTO TUESDAY. BY LATE TUESDAY AND WEDNESDAY...THE NEXT UPPER LEVEL WAVE PUSHING INTO THE PLAINS WILL DEVELOP LOW PRESSURE TO OUR WEST. WARM ADVECTION PRECIP WITH THIS FEATURE WILL SPREAD RAIN CHANCES EAST OF THE MS RIVER FOR MID- WEEK. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SATURDAY EVENING FOR ILZ027>031- 036>038-040>042-047>051. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
300 PM EDT THU MAY 30 2013 .SYNOPSIS... ISSUED AT 1038 AM EDT THU MAY 30 2013 A WEAK SYSTEM MOVING INTO THE REGION COULD SPAWN A FEW SHOWERS OR ISOLATED STORMS FROM MIDDAY INTO THIS EVENING. TEMPERATURES WILL RISE INTO THE MID TO UPPER 80S. WHILE THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE LATER THIS WEEKEND...THE CHANCE OF SHOWERS AND A FEW NON SEVERE STORMS CAN NOT BE RULED OUT OVERNIGHT. LOWS TONIGHT WILL BE IN THE UPPER 60S. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 300 PM EDT THU MAY 30 2013 THE MAIN FOCUS THIS PERIOD IS ON CONVECTIVE POTENTIAL/EVOLUTION. SYNOPTICALLY...A CLOSED LOW WILL MEANDER SLOWLY EAST ACROSS THE NORTHERN PLAINS WITH DEEP/MOIST CYCLONICALLY CURVED SOUTHWEST FLOW IN PLACE FROM THE SOUTHERN PLAINS NORTHEAST INTO THE GREAT LAKES REGION. AT THE SURFACE THE PRIMARY SFC FRONT FRONT WILL BE DRAPED FROM THE UPPER MIDWEST SOUTHWEST INTO THE SOUTHERN PLAINS WITH A MOIST/HUMID/UNSTABLE AIRMASS OUT AHEAD OF THIS. THE REMAINDER OF THE AFTERNOON INTO EARLY THIS EVENING... 19Z REGIONAL RADAR MOSAIC SHOWING SCATTERED CONVECTION FIRING ACROSS MUCH OF ILLINOIS IN A ZONE OF WEAK MOISTURE CONVERGENCE ON THE EASTERN FLANK OF A CONVECTIVELY ENHANCED/INDUCED SHORTWAVE LIFTING INTO WEST-CENTRAL ILLINOIS...WITH ISOLATED CONVECTION STARTING TO POP ACROSS THE LOCAL AREA. LATEST RAP ANALYSIS SHOWS 1500-2000 J/KG OF MLCAPE ACROSS THE AREA WITH LITTLE/NO CIN. EXPECT ISOLATED TO SCATTERED CONVECTION TO MAINLY IMPACT AREAS ALONG AND WEST OF INTERSTATE 69 INTO THE EARLY EVENING AS WEAK FORCING AND CONTINUED LOW/MID LEVEL THETA-E ADVECTION ADVECTS OVER THIS AREA. MARGINAL 20-25 KNOTS OF DEEP LAYER EFFECTIVE SHEAR A DEFINITE LIMITING FACTOR FOR ORGANIZATION AND ISOLATED SEVERE STORMS...ALTHOUGH CANNOT RULE OUT AN ISOLATED DAMAGING WIND/HAIL THREAT IF ANY MULTICELL CLUSTERS/SMALL LINE SEGMENTS TAKE SHAPE. LARGE SCALE UPPER SUPPORT WILL INCREASE TONIGHT INTO FRIDAY MORNING AS A MORE PRONOUNCED MID LEVEL SHORTWAVE TROUGH NOW EJECTING INTO THE CENTRAL PLAINS ON THE NOSE OF AN UPPER JET TRANSLATES NORTHEAST INTO THE WESTERN/NORTHERN GREAT LAKES. THIS SUPPORTS THE IDEA OF LATEST HI-RES GUIDANCE IN MAINTAINING A WEAKENING MESOSCALE CONVECTIVE SYSTEM (ACROSS CENTRAL IOWA INTO WESTERN MISSOURI AS OF THIS WRITING) EAST INTO AT LEAST OUR WESTERN ZONES AFTER 05/06Z ISH. MEAGER MID LEVEL LAPSE RATES COUPLED WITH DIURNAL COOLING SHOULD ALLOW WHAT MIGHT BE A LINE OF SEVERE CONVECTION INTO ILLINOIS THIS EVENING TO WEAKEN (FALL APART?) AS IT ATTEMPTS TO MAKE INTO THE LOCAL AREA FROM WEST TO EAST OVERNIGHT...WITH SHOWERS/ISO THUNDER POSSIBLY LINGERING INTO FRIDAY MORNING ALONG THE MCS/MCV RESIDUAL OUTFLOW BOUNDARY. BUMPED UP POPS A BIT AFTER MIDNIGHT....HIGHEST WEST. SUBSIDENCE/AVA BEHIND THE MID LEVEL TROUGH AXIS LATER FRIDAY MORNING INTO THE EARLY/MID AFTERNOON HOURS WITH ATMOSPHERE POSSIBLY WORKED OVER FROM MORNING CLOUDS/SHOWERS SHOULD RESULT IN A LULL IN PCPN ACROSS THE AREA DURING THIS TIME. ALTHOUGH RETAINED LOW 20-30 PERCENT POPS BTW 15-21Z AS RENEWED CONVECTION COULD FORM ALONG THE RESIDUAL OUTFLOW BOUNDARY BY EARLY/MID AFTERNOON...BEST CHANCES ACROSS OUR SOUTHEASTERN ZONES. CHANCES FOR ADDITIONAL CONVECTION...POTENTIALLY SEVERE...BY LATE AFTERNOON AND EVENING ARE DISCUSSED IN THE LONG TERM SECTION. && .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 300 PM EDT THU MAY 30 2013 POTENT SW AND ATTENDANT CLOSED LOW OVR SD IS XCPD TO OPEN FRI NIGHT AND KICK EWD ACRS THE LAKES IN RESPONSE OF ARRIVAL OF UPSTREAM KICKER INTO THE PACNW. AT THE SFC...PRONOUNCED SFC WAVE OVR SRN MN SAT MORNING WILL EJECT EWD TO LK HURON BY SUN MORNING AS ASSOCD TRAILING CDFNT SURGES EWD. BEST LL MSTR FLUX/LL THETA-E RIDGING XCPD FRI EVENING W/AGAIN A CONDITIONAL SVR THREAT PENDING SHRT TERM CONV EVOLUTION/MAINTAINANCE INTO THE WRN LAKES FRI AFTN. OTRWS STG SFC CDFNT TO CROSS CWA SAT AFTN/EVE W/STG FORCING FOR ASCENT WITHIN CONTD SIG LL MSTR PLUME AND LIKELY MOST FVRBL WINDOW FOR SIG RAINFALL. STG CAA FOLLOWS ON SUN W/RAPID NEWD ADVTN OF MID LVL DRYSLOT UNDERNEATH MID LVL TROUGH PIVOTING THROUGH MI. GIVEN GENERAL 12Z CONSENSUS SOLUTION WILL DROP LOW CHC POPS MOST AREAS SANS FAR SE. DRY AND SEASONABLE WX XPCD THROUGH UNTIL THE END OF THE PD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1217 PM EDT THU MAY 30 2013 MAINLY VFR THROUGH THE PERIOD WITH PRIMARY FOCUS ON CONVECTIVE POTENTIAL THIS AFTERNOON AND EARLY EVENING. MODERATE INSTABILITY THIS AFTERNOON COINCIDENT WITH CONTINUED LOW/MID LEVEL THETA-E ADVECTION AND A SHORTWAVE LIFTING NORTHEAST INTO ILLINOIS SHOULD ALLOW FOR A FEW SHOWERS/STORMS TO DEVELOP AROUND 19-20Z. KEPT THE 2 HOUR TEMPO TSRA/MVFR GROUP AT SBN WHERE BETTER CHANCES FOR CONVECTION RESIDES. LESSER CHANCES AT FWA WHERE VCTS/VFR GROUP ADDED BTW 20-01Z. SHOWER/STORM ACTIVITY SHOULD DIMINISH BTW 23-02Z GIVEN LOSS OF HEATING AND WEAK FORCING...LEAVING MOST OF THE EVENING DRY/VFR. CONFIDENCE BEYOND MIDNIGHT IS LOW AS A WEAKENING UPSTREAM CONVECTIVE COMPLEX ACROSS MISSOURI/IOWA MAKES A RUN AT THE GREAT LAKES. ADDED A VCSH MENTION AFTER 07Z AT SBN AS WEAKENING LINE OF SHOWERS/STORMS MAY HOLD TOGETHER INTO NORTHWEST INDIANA. RETAINED OPTIMISTIC DRY FCST AT FWA. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR LMZ043-046. && $$ SYNOPSIS...BENTLEY SHORT TERM...STEINWEDEL LONG TERM...T AVIATION...STEINWEDEL VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
350 PM CDT THU MAY 30 2013 .SHORT TERM.../TONIGHT /... ISSUED AT 350 PM CDT THU MAY 30 2013 MAIN SHORTWAVE LIFTING THROUGH THE BASE OF THE UPPER LEVEL TROUGH RESPONSIBLE FOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS THE FAR SOUTHEASTERN CWA. AS SHORTWAVE CONTINUES TO LIFT NORTHEAST THROUGH THE EASTERN PORTION OF THE STATE...AREA OF SHOWERS/THUNDERSTORMS WILL CONTINUE TO SHOVE EAST OUT OF THE CWA. LOOKING BACK TO THE WEST...HAVE SOME ISOLATED WEAK CELLS DEVELOPING ACROSS CENTRAL NE/KS. THIS ACTIVITY MAY APPROACH THE SOUTHWESTERN/SOUTHERN CWA BY MID EVENING...BUT IS EXPECTED TO BE RELATIVELY WEAK WITH LESS THAN 1000 J/KG CAPE ON NAM/RAP SOUNDINGS. HRRR SEEMS TO BE GRASPING CURRENT RADAR TRENDS CORRECTLY...SO KEPT POPS CLOSE TO THE HRRR OUTPUT. THE WESTERN ACTIVITY IS MOSTLY DIURNALLY DRIVEN...SO EXPECT IT TO DIMINISH TOWARD SUNSET. ANOTHER WAVE OF ENERGY TO ROUND THE BASE OF THE UPPER LEVEL TROUGH TO APPROACH THE STATE LATE TONIGHT...MAY ALLOW FOR SOME SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP TOWARD SUNRISE FRIDAY MORNING. THE DEEP MOISTURE THAT HAS BEEN IN PLACE ACROSS THE STATE OVER THE PAST WEEK...IS BEGINNING TO PUSH EAST WITH THE ADVANCEMENT OF A DRY LINE OVER CENTRAL NE/KS...THEREFORE THE HEAVY RAIN THREAT WILL BE LESSENED WITH ANY ACTIVITY THAT DEVELOPS LATE TONIGHT/EARLY FRIDAY MORNING. .LONG TERM.../FRIDAY THROUGH THURSDAY/... ISSUED AT 350 PM CDT THU MAY 30 2013 AN UPPER LEVEL LOW PRESSURE SYSTEM WILL REMAIN NEARLY STATIONARY OVER THE DAKOTAS AND MINNESOTA FRIDAY AND FRIDAY NIGHT...BEFORE MOVING EASTWARD ACROSS IOWA ON SATURDAY AND AWAY OVER THE GREAT LAKES ON SATURDAY NIGHT. ON FRIDAY MORNING LOW LEVEL FLOW WILL STILL BE FROM THE SOUTH SOUTHWEST AND AN APPROACHING SHORTWAVE MOVING AROUND THE UPPER LOW SHOULD KICK OFF THUNDERSTORMS ACROSS EASTERN KANSAS LATE TONIGHT THAT WILL MOVE ACROSS OUR SOUTHERN AND EASTERN COUNTIES ON FRIDAY. HAVE INCREASED POPS INTO THE 70 TO 80 PERCENT RANGE IN OUR SOUTHEAST TO ACCOUNT FOR THIS...AND SEVERE WEATHER WILL BE POSSIBLE IN THESE AREAS AS WELL. FRIDAY SHOULD BE FAIRLY WARM ESPECIALLY IF SKIES ARE ABLE TO CLEAR ACROSS MUCH OF THE CWA...AND HAVE RAISED FORECAST HIGHS A BIT EVEN INTO THE LOWER 80S IN SOME AREAS. BY FRIDAY EVENING THE DAYTIME STORMS WILL BE EXITING TO THE EAST AHEAD OF A SURFACE TROUGH MOVING ACROSS THE AREA. WINDS BEHIND THIS TROUGH WILL TURN TO WEST AND THEN NORTHWEST WITH COOLER AIR FLOWING INTO THE AREA. IN ADDITION...AS THE UPPER LEVEL LOW PRESSURE TROUGH MOVES ACROSS OUR AREA ON SATURDAY IT WILL BE ACCOMPANIED BY THICK CLOUDS AND LIGHT SHOWERS MAKING FOR A GREY AND DAMP DAY. NO THUNDERSTORMS ARE ANTICIPATED AND ANY RAINFALL AMOUNTS WILL BE LIGHT. COVERAGE IS UNCERTAIN SO HAVE MAINTAINED POPS BELOW 50 PERCENT...BUT THIS MAY NEED TO BE INCREASED LATER IN A CLASSIC HIGH POP/LOW QPF SCENARIO. BY SUNDAY A SURFACE RIDGE WILL BUILD IN MAKING FOR MOSTLY CLEAR AND DRY BUT COOL WEATHER WITH LIGHT NORTH WINDS. FROM SUNDAY NIGHT THROUGH THURSDAY THE 500 MB PATTERN WILL UNDERGO AN EERILY SIMILAR EVOLUTION TO WHAT WE HAVE SEEN OVER THE LAST SEVERAL DAYS...AS ANOTHER UPPER LOW MOVES INTO THE NORTHWESTERN U.S. AND THEN ACROSS THE UPPER MIDWEST. THIS WILL RESULT IN ANOTHER EXTENDED PERIOD OF THUNDERSTORM CHANCES FOR OUR AREA FROM MONDAY NIGHT THROUGH THE END OF THE FORECAST PERIOD. HOWEVER...UNLIKE THE SYSTEM OF THE PAST SEVERAL DAYS...THE 500 MB LOW NEXT WEEK WILL NOT HAVE AS MUCH LATITUDINAL EXTENT AND WILL BE GENERALLY MORE PROGRESSIVE...MITIGATING SOMEWHAT THE POTENTIAL FOR EXTENDED HEAVY RAINFALL. THE DETAILS OF THE RAINFALL FORECAST FOR NEXT WEEK WILL BE IRONED OUT LATER...BUT AT LEAST THERE WILL BE SEVERAL RELATIVELY DRY DAYS THIS WEEKEND TO ALLOW CURRENT FLOOD WATERS TO SUBSIDE...AND RAINFALL AMOUNTS NEXT WEEK SHOULD BE CONSIDERABLY LIGHTER IN MOST AREAS WITH THE PRIMARY CHANCES LIMITED TO THE MONDAY NIGHT...TUESDAY...AND TUESDAY NIGHT PERIODS. && .AVIATION...30/18Z ISSUED AT 103 PM CDT THU MAY 30 2013 AREA OF SHOWERS AND MVFR CIGS ACROSS THE AREA...SHOULD CONTINUE TO SLIGHTLY MOVE NORTH AND EAST THROUGH THE AFTERNOON. CHANCES FOR THUNDERSTORMS TO INCREASE ESPECIALLY AT THE EASTERN TAF SITES THIS AFTERNOON INTO EARLY EVENING. MAJORITY OF PRECIPITATION CHANCES EXPECTED TO END ACROSS THE CWA BY MID EVENING...WITH POSSIBLY HIGH MVFR TO LOW VFR CIGS EXPECTED OVERNIGHT. POSSIBILITY OF FOG REDUCING VSBYS/CIGS LATE TONIGHT DUE TO ABUNDANT MOISTURE AROUND...HOWEVER VERY UNCERTAIN SO HAVE NOT PLACED IN THE TAF AT THIS TIME. GUSTY SOUTHERLY WINDS EXPECTED THROUGH THE PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR SOUTHEAST BUTLER. && $$ SHORT TERM...BEERENDS LONG TERM...LEE AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
344 PM CDT THU MAY 30 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 343 PM CDT THU MAY 30 2013 WATER VAPOR LOOP SHOWING CONVECTIVE SYSTEM OVER WESTERN MO MOVING SLOWLY EWD AHEAD OF ONE MID-LEVEL TROUGH. HOWEVER...THERE IS A VERY SHORT WAVELENGTH BETWEEN THAT TROUGH AND THE FOLLOWING IMPULSE THAT APPEARS TO BE OVER WRN KS AT MID AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS HAVE FIRED OVER WRN KS AHEAD OF THIS FEATURE AND THEY ARE MOVING EWD. SHORT RANGE MODEL GUIDANCE NOT RESOLVING THE DETAILS OF THIS VERY WELL...HOWEVER THE 17Z HRRR DOES NOW HAVE A LINE OF CONVECTION MOVING INTO CENTRAL KS BY 21Z. IT FORECASTS THIS TO BREAK UP WITH THE REMNANTS MOVING ACROSS NORTHEAST KS DURING THE EVENING...AND THEN ANOTHER SMALL CONVECTIVE SYSTEM MOVES SOUTHEAST OUT OF NEBRASKA INTO NORTHEAST KS LATER TONIGHT. DO NOT HAVE HIGH CONFIDENCE IN THIS SCENARIO...ALTHOUGH SOME TYPE OF SMALL MCS WOULD APPEAR TO BE LIKELY IN CENTRAL/NORTHEAST KS LATER TONIGHT. THIS POSSIBLE SYSTEM WOULD APPEAR TO MOVE THROUGH FAST ENOUGH AS TO NOT CAUSE SIG PROBLEMS WITH HEAVY RAIN/FLOODING. EARLIER CONCERNS ABOUT WARM AIR ADVECTION CAUSING LIFT AND THUNDERSTORM AREA WITH POTENTIALLY HEAVY RAINFALL OVER EC KS TONIGHT ARE LESSENING AS CONVECTIVE BOUNDARY SAGS WAY SOUTH INTO NORTHEAST OKLAHOMA. THUS...HAVE CANCELLED FLASH FLOOD WATCH THAT WAS IN EFFECT FOR THIS AFTERNOON...AND AM NOT PLANNING ON GOING OUT WITH A NEW ONE AT THIS TIME. CONFIDENCE IN THE DETAILS OF PRECIPITATION EVOLUTION TONIGHT IS NOT HIGH. ON FRIDAY...FRONTAL BOUNDARY SHOULD MAKE IT FAR ENOUGH SOUTH BY AFTERNOON THAT THE MAIN CHANCE OF THUNDERSTORM ACTIVITY WOULD BE IN EC KS...MAINLY SOUTHEAST OF THE KANSAS TURNPIKE. LOWS TONIGHT EXPECTED TO BE AROUND 60 OVER NC KS AND IN THE MID 60S EC. HIGHS ON FRIDAY ARE FORECAST TO MAX OUT AROUND 80. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 343 PM CDT THU MAY 30 2013 DETAILS ONLY GET MURKIER FOR FRIDAY EVENING...BUT AT LEAST SOME CHANCE SHOULD EXIST AHEAD OF THE SYNOPTIC BOUNDARY FOR SOUTHERN AND EASTERN LOCATIONS. SUFFICIENT SHEAR AND INSTABILITY WOULD SUPPORT A SEVERE CONCERN THROUGH THIS TIME AS WELL..BUT THE SOUTHEASTWARD SHIFTING UPPER LOW SHOULD PUSH THE EFFECTIVE FRONT SOUTH OF THE AREA BY DAWN. COLD AIR ADVECTION SETS IN FOR SATURDAY ON NORTHWEST BREEZES WITH SOME STRATUS/STRATOCU DEVELOPING BY MID AFTERNOON. WEAKENING WINDS AND CLEARING SKIES SPELL A COOL NIGHT SATURDAY NIGHT. SURFACE RIDGE SETS UP FOR SUNDAY WITH LITTLE IF ANY MODERATION TO HIGHS. GULF MOISTURE DOES NOT GET COMPLETELY SCOURED OUT...AND BY LATE MONDAY SOUTH WINDS AHEAD OF AN APPROACHING NORTHERN ROCKIES CYCLONE WILL BRING THUNDERSTORM CHANCES BACK. BEST CHANCES LOOK TO BE TUESDAY INTO TUESDAY NIGHT WITH GOOD MODEL AGREEMENT ON A MID LEVEL WAVE PASSING. TEMPS SHOULD GENERALLY BE NEAR EARLY JUNE NORMALS SAVE ANY DAYTIME MCS ACTIVITY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1239 PM CDT THU MAY 30 2013 CHALLENGING FORECAST. LINE OF SHOWERS SHOULD HAVE MOVED THROUGH TOP AND FOE BY A LITTLE AFTER 18Z TODAY. THEN ANOTHER CHANCE OF SHOWERS AND STORMS LATE AFTERNOON EARLY EVENING...AND ANOTHER CHANCE LATE TONIGHT AND FRIDAY MORNING. OTHER THAN IN SHOWERS...WINDS SHOULD BE FROM THE SOUTH. POTENTIAL MVFR CONDITIONS IN SOME OF THE HEAVIER SHOWERS AND STORMS. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...60 LONG TERM...65 AVIATION...PHILLIPS
AREA FORECAST DISCUSSION
NWS JACKSON KY
128 PM EDT THU MAY 30 2013 .UPDATE... ISSUED AT 127 PM EDT THU MAY 30 2013 WILL UPDATE NDFD HOURLY DATA AND WEB SERVERS BY 135 PM FOR LATEST OBSERVATIONAL TRENDS. UPDATE ISSUED AT 1037 AM EDT THU MAY 30 2013 NDFD AND WEB SERVERS HAVE BEEN UPDATED FOR LATEST SATELLITE AND SURFACE OBSERVATIONAL TRENDS. ZFP UPDATE NOT NEEDED AT THIS TIME. THE 12Z HRRR POINTS TOWARDS ISOLATED SHOWERS BEING POSSIBLE OVER THE FAR WESTERN PART OF THE FORECAST AREA FOR A FEW HOURS THIS AFTERNOON...SIMILAR TO YESTERDAY. EXPECT PROBABILITY TO REMAIN BELOW 15 PERCENT AND WILL NOT ADD THIS TO FORECAST. THE 12Z NAM SUPPORTS A DRY FORECAST THIS AFTERNOON....WITH LOW PROBABILITY OF SHOWERS IN THE WESTERN PART OF THE AREA TONIGHT. THIS IS IN THE CURRENT FORECAST FOR TONIGHT AND WILL LEAVE AS IS FOR NOW. UPDATE ISSUED AT 750 AM EDT THU MAY 30 2013 UPDATED THE FORECAST MAINLY TO KEEP THE NEAR TERM GRIDS ON TRACK WITH THE CURRENT OBS AND TRENDS...INCLUDING SKY COVER. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 335 AM EDT THU MAY 30 2013 06Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE EAST OF KENTUCKY AND DEEP LOW PRESSURE WELL TO THE NORTHWEST. A SOUTHERN FLOW OF WARMTH AND MOISTURE CONTINUES THROUGH THE STATE BETWEEN THESE TWO KEY FEATURES. ON SATELLITE...SOME HIGH CLOUDS AND A SMALLER BATCH OF LOWER ONES ARE CROSSING EAST KENTUCKY EARLY THIS MORNING. THESE CLOUDS HAVE ONLY HAD A SMALL IMPACT ON THE RADIATIONAL COOLING THROUGH THE CWA THIS NIGHT WITH RIDGES STAYING UP IN THE UPPER 60S AND LOWER 70S WHILE THE MOST SHELTERED VALLEYS CONTINUE THEIR PLUNGE INTO THE UPPER AND MIDDLE 50S. ALSO SIMILAR TO LAST NIGHT...DEEPER LOCATIONS IN THE WESTERN PORTIONS OF THE CUMBERLAND VALLEY...WEST OF I-75...ARE STAYING A BIT MILDER WHEN COMPARED TO VALLEYS FURTHER EAST. AT THE SAME TIME...DEWPOINTS ARE IN THE LOWER 60S THROUGHOUT THE AREA. WITH THE VALLEY TEMPS FALLING TO NEAR THEIR DEWPOINTS...DO EXPECT SOME LIGHT FOG TO DEVELOP IN THE PREDAWN HOURS...BUT STILL BE MAINLY CONFINED TO THE LOCATIONS ALONG RIVERS AND OTHER BODIES OF WATER. THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN AFFECTING THE REGION THROUGH THE SHORT TERM. THEY ALL SHOW THE SOUTHEAST RIDGE STRONGLY INFLUENCING EAST KENTUCKY FOR AT LEAST ONE MORE DAY WHILE A LARGE AREA OF TROUGHING CONSOLIDATES OVER THE HIGH PLAINS. HEIGHTS WILL START TO FALL LOCALLY LATER TONIGHT AS THE BROAD TROUGH TO THE NORTHWEST PRESSES IN ON THE WESTERN FRINGES OF THE OHIO VALLEY. THIS PROCESS WILL BE ACCOMPANIED BY A LEADING BAND OF SHORTWAVE ENERGY CROSSING INTO THE REGION BY DAWN FRIDAY...JUST NORTH OF THE OHIO RIVER. THIS BAND WEAKENS DURING THE DAY FRIDAY AS IT ADVANCES EAST INTO THE RETREATING RIDGE. THE NAM12 AND GFS HAVE SIMILAR IDEAS WITH THIS FIRST BATCH OF ENERGY AND ITS EFFECT ON WEATHER SO HAVE GONE WITH A BLEND OF THESE TWO MODELS FOR WX SPECIFICS THROUGH FRIDAY. SENSIBLE WEATHER WILL SEE THE WARM AND INCREASINGLY MUGGY AIR MASS SET THE STAGE FOR MORE IN THE WAY OF CONVECTION TO CLOSE OUT THE WORK WEEK. HIGHER PW AIR CONTINUES TO BUILD OVER EAST KENTUCKY TODAY AND FRIDAY. STILL CANNOT RULE OUT SOME STRAY POP UP STORMS LATE THIS AFTERNOON...MAINLY JUST TO OUR WEST...BUT WITH CHANCES STILL TOO LOW TO MENTION IN THE ZONES OR REPRESENT IN THE WX GRIDS AT THIS TIME. THIS IS DESPITE LOW LIS AND MODERATELY HIGH CAPE...AS A TRIGGER WILL BE HARD TO COME BY UNTIL LATER. A BETTER CHANCE FOR CONVECTION WILL OCCUR LATER TONIGHT...AGAIN PRIMARILY OVER OUR WESTERN ZONES...AS THE APPROACHING MID LEVEL WAVE WILL HELP YO ACTIVATE THIS INCREASINGLY SOUPY AIR MASS. THIS DEVELOPMENT WILL KEEP A DECENT THREAT OF SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGHOUT THE DAY FRIDAY...WORKING WEST TO EAST WITH TIME. THE EXPECTED INCREASE IN CLOUD COVER AND CONVECTION WILL ALSO LIKELY SERVE TO CAP TEMPERATURES IN THE MID 80S ON FRIDAY...A TAD LOWER THAN TODAY. BEFORE THE MORE ORGANIZED AREA OF CONVECTION GETS GOING LATE TONIGHT...DO EXPECT ANOTHER SMALL TO MODERATE RIDGE AND VALLEY TEMPERATURE SPLIT TO DEVELOP BY LATE EVENING THOUGH MUCH OF THIS WILL BE WASHED OUT BY THE LOWER CLOUDS AND SCATTERED COVERAGE OF SHOWERS AND THUNDERSTORMS TOWARD DAWN FRIDAY. HAVE USED THE CONSSHORT FOR TD AND WINDS THROUGH THE FIRST 24 HOURS AS A STARTING POINT...PERSISTENCE FOR HIGHS TODAY AND A MODIFIED VERSION OF THIS NIGHT/S LOWS FOR TONIGHT. FOR FRIDAY...FAVORED THE CONSALL FOR HIGHS. DID USE A DIURNAL FROM OBS SCHEME FOR HOURLY T GRIDS WITH SOME ADJUSTMENTS LATE TONIGHT TO ACCOUNT FOR THE INCREASE IN CLOUDS AND SCATTERED CONVECTION. AS FOR POPS...KEPT THEM IN LINE WITH LOW MOS GUIDANCE TODAY BEFORE ENDING UP CLOSER TO THE HIGHER MET NUMBERS TONIGHT AND THE LOWER MAV ONES ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 300 AM EDT THU MAY 30 2013 GENERAL AGREEMENT AMONGST THE FORECAST MODELS ONCE AGAIN FOR THE EXTENDED PERIOD OF THE FORECAST. THE GFS AND ECMWF SOLUTIONS WERE PREFERRED FOR THIS RENDITION OF THE EXTENDED DUE TO THEIR SIMILARITIES. THE TIMING OF THE PASSAGE OF A COLD FRONT SATURDAY NIGHT INTO SUNDAY WAS CAPTURED WELL BY BOTH PREFERRED MODELS. THE MODELS BOTH HAVE DEVELOPED A SLUGGISH FRONTAL PROGRESSION WHERE THE FRONT GETS HUNG UP A BIT NORTH OF THE OHIO SATURDAY EVENING. IT APPEARS THAT THE RIDGE THAT WILL DOMINATE THE WEATHER TODAY AND TOMORROW WILL BE VERY SLOW TO WEAKEN AND MOVE OFF TO THE EAST. WITH THIS IN MIND...DECIDED TO MODIFY THE FORECAST TOWARD THE SLOWER FRONTAL PROGRESSION SEEN IN BOTH THE GFS AND ECMWF. ISOLATED SHOWERS AND STORMS WILL BE POSSIBLE...AS A WEAK IMPULSE PUSHES ACROSS THE OHIO VALLEY FRIDAY EVENING. ONCE THIS BIT OF ENERGY EXITS THE AREA FRIDAY NIGHT...THERE SHOULD ANOTHER LULL IN THE PRECIPITATION...AS HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA DURING THE DAY ON SATURDAY. ONCE THE RIDGE FINALLY BREAKS DOWN AND MOVES OFF TO THE EAST...A COLD FRONT WILL PUSH ACROSS THE OHIO AND TENNESSEE VALLEYS SATURDAY NIGHT THROUGH SUNDAY NIGHT. WIDESPREAD SHOWERS AND STORMS ARE LIKELY TO ERUPT ALONG AND JUST IN ADVANCE OF THIS BOUNDARY...AS MOIST AIR FROM THE GULF OF MEXICO POURS INTO THE AREA ON SOUTHWESTERLY AND SOUTHERLY WINDS. THE LATEST FORECAST SOUNDINGS WERE SHOWING MUCH BETTER INSTABILITY AND WIND SHEAR DURING THE DAY ON SUNDAY...PARTICULARLY DURING THE AFTERNOON AND EVENING HOURS. WITH CONDITIONS A BIT MORE JUICY AND ENERGETIC...THE POSSIBILITY FOR A FEW STRONG STORMS WILL EXIST ON SUNDAY...WITH STRONG WINDS AND HAIL POSSIBLE. THE SOUNDINGS ALSO ARE SHOWING THE POTENTIAL FOR LOCALLY HEAVY RAINFALL...SO THIS WILL PRESENT THE POSSIBILITY OF LOCALIZED HYDROLOGY ISSUES WITH THE STRONGER STORMS OR WHERE SHOWERS AND STORM MOVE REPEATEDLY ACROSS THE SAME AREAS. WITH THE MODELS BEING IN GOOD AGREEMENT...AND THE MODELS SHOWING FAVORABLE CONDITIONS FOR SHOWERS AND STORMS TO FORM...WENT VERY CLOSE TO THE MEXMOS POPS FOR SATURDAY NIGHT AND SUNDAY. THE PERIOD WILL BEGIN WITH WELL ABOVE NORMAL TEMPERATURES...AS SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONT BRINGS WARM MOIST AIR INTO THE AREA IN LARGE QUANTITIES. AFTER THE FRONT PASSES THROUGH THE AREA LATE SUNDAY NIGHT...A MUCH COOLER AIR MASS WILL FILTER INTO THE AREA...PAVING THE WAY FOR NORMAL TEMPERATURES MONDAY AND TUESDAY. HIGHS EACH DAY WILL TOP OUT IN THE MID 70S. TEMPERATURES ON SUNDAY WILL ALSO BE AROUND NORMAL DUE TO THE INFLUENCE OF PRECIPITATION AND CLOUD COVER. ANOTHER RIDGE OF HIGH PRESSURE WILL THEN SETTLE OVER THE REGION ON TUESDAY WEDNESDAY...BRINGING COOLER AND DRIER WEATHER TO EASTERN KENTUCKY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 127 PM EDT THU MAY 30 2013 HIGH PRESSURE ALONG THE EAST COAST WILL SLIDE SLOWLY EAST WHILE A CENTER OF LOW PRESSURE MOVES SLOWLY EAST THROUGH THE NORTHERN PLAINS. A TROUGH OF LOW PRESSURE EXTENDING FROM THE NORTHERN PLAINS LOW WILL SWING THROUGH THE MID MS VALLEY AND INTO THE GREAT LAKES BY FRIDAY. THIS LOW PRESSURE TROUGH WILL BRING AN INCREASE IN CLOUD COVER LATE TONIGHT AND INTO FRIDAY...BUT CEILINGS ACROSS THE REGION WILL REMAIN VFR. IT APPEARS THAT THE SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE LOW PRESSURE TROUGH WILL BE DECAYING AS THEY MOVE EAST INTO EASTERN KY FRIDAY MORNING AND FOR NOW WILL LEAVE OUT OF THE TAFS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...GREIF LONG TERM...AR AVIATION...SBH
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1249 PM CDT THU MAY 30 2013 .UPDATE... FOR 18Z AVIATION DISCUSSION BELOW. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 353 AM CDT THU MAY 30 2013 A VERY ACTIVE SHORT TERM IS IN STORE AS A POTENT UPPER WAVE WORKS ACROSS THE NATIONS MIDSECTION. H5 RAP ANALYSIS SHOWS A CLOSED LOW HAS DEVELOPED NEAR THE BLACK HILLS THIS MORNING...WITH A NEGATIVELY TITLED TROUGH EXTENDING FROM THERE DOWN TO NORTHEAST TEXAS. THE RADAR MOSAIC WEDNESDAY WAS CRAMMED FULL OF CONVECTION FROM HERE ALL THE WAY DOWN TO TEXAS...WHICH MEANS WITHIN THIS LARGE SCALE TROUGH THERE ARE NUMEROUS LEFT OVER WAVES/MCVS. ONE SUCH WAVE IS OVER SW IA THAT WILL SWING THROUGH HERE IN THE LATE MORNING. THE MAIN SYNOPTIC UPPER WAVE WILL BEGIN WORKING ACROSS MN THIS AFTERNOON AND EVENING. TO GO ALONG WITH ALL OF THE WAVES...A 50 KT LLJ IS CURRENTLY BLOWING ACROSS MN. THIS LLJ WILL SLOWLY DIMINISH THROUGH THE MORNING...BUT A MUCH STRONGER PUSH CURRENTLY OVER OK/KS WILL COME UP INTO SE MN/WRN WI THIS AFTERNOON/EVENING WITH THE PRIMARY SYNOPTIC WAVE. AT THE SFC...A 995 MB SFC LOW CAN BE FOUND NEAR PIERRE SOUTH DAKOTA...WITH A WARM FRONT SITTING ACROSS CENTRAL MN. DURING THE SHORT TERM...THIS LOW WILL BECOME OCCLUDED AND SLOWLY MEANDER NORTH INTO NODAK. THE WARM FRONT WILL CONTINUE TO MOVE NORTH TODAY...EVENTUALLY SETTLING ALONG THE INTERNATIONAL BORDER. BACK TO THE WEST...A COLD FRONT MOVING ACROSS SODAK TODAY WILL BE ENTERING WRN MN BY THE END OF THE PERIOD. FOR TODAY...EXPECT A BRIEF LULL IN ACTIVITY THIS MORNING AS WE WAIT FOR THE WAVE OVER SW IA TO GET HERE AROUND 15Z. FORECAST SOUNDINGS ACROSS THE ENTIRE CWA SHOW VERY LITTLE IF ANY CAPPING...SO EXPECT SHOWERS AND STORMS TO DEVELOP QUICKLY THIS MORNING ONCE A LITTLE DAYTIME HEATING KICKS IN. SINCE WE WILL NOT BE ABLE TO BUILD MUCH INSTABILITY THANKS TO DENSE CLOUD COVER AND THE FACT THAT ONCE A LITTLE DEVELOPS THE ATMO WILL QUICKLY CONSUME IT...THE SEVERE THREAT LOOKS FAIRLY LOW TODAY. FOR SEVERE WEATHER...WILL HAVE TO WATCH THAT SECOND LLJ WORKING UP IN THE AFTERNOON. BY 00Z THE RAP HAS 50 KT WINDS AT H85 UP INTO OUR WI CWA. LIKE YESTERDAY...THIS COULD LEAD TO THE THREAT FOR BOWING LINE SEGMENTS AND DAMAGING WINDS. AS FOR ANY HYDROLOGY ISSUES TODAY...THE ONLY AREA THAT WILL PROBABLY HAVE TO BE WATCHED IS THE EAU CLAIRE AREA. THEY SET A DAILY RAINFALL RECORD YESTERDAY AND WILL BE UNDER THE GUN FOR THE SECOND LLJ SURGE THIS AFTERNOON...WITH THE POTENTIAL FOR SOME TRAINING OF STORMS THIS AFTERNOON AND EVENING. TONIGHT...THE COLD FRONT WILL START ENTERING WRN MN WHILE THE LLJ WORKS INTO CENTRAL/ERN WI. THIS SHOULD MOVE THE HEAVY RAIN THREAT EAST OF THE MPX CWA TONIGHT. HOWEVER...HI-RES CAMS SHOW SCT RETURNS CONTINUING THROUGH THE NIGHT AHEAD OF THE FRONT...SO HAVE POPS SLOWLY RAMPING DOWN FROM LIKELIES TO START THE EVENING...DOWN TO 50% POPS OR LESS BY 12Z FRIDAY. FOR TEMPERATURES...GIVEN ALL OF THE CLOUD COVER...IT WILL NOT BE AN OVERLY WARM WARM SECTOR TODAY...WITH HIGHS LIKELY STAYING IN THE MID TO UPPER 70S...DESPITE H85 TEMPS BEING UP AROUND +15C. FOR TONIGHT...MIXED LAYER DEWPS ON THE NAM DROP INTO THE 40S BEHIND THE FRONT...SO LOWS IN THE WRN CWA COULD END UP BEING A FEW DEGREES COOLER THAN WHAT IS CURRENTLY INDICATED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 353 AM CDT THU MAY 30 2013 MODELS INDICATE RATHER STRONG TROUGH AXIS WORKING THROUGH THE AREA BY FRIDAY MORNING. THIS SHOULD WORK MUCH OF THE RAIN AND THUNDER TO THE NORTH AND EAST OF THE AREA LATE THURSDAY NIGHT. THIS SHOULD WORK A DRY SLOT NORTHEAST INTO SOUTHWEST PORTION OF THE CWA DURING FRIDAY MORNING. THE UPPER CIRCULATION THEN MOVES A FRONTAL BOUNDARY EAST ACROSS EASTERN HALF OF THE CWA FRIDAY AFTERNOON. THE DETERMINISTIC MODELS ARE INDICATING MODEST DESTABILIZATION ACROSS THE EASTERN HALF OF THE AREA...WITH ML MUCAPE INCREASING TO 1500/2000 J/KG. SHEAR INCREASES INTO THE AFTERNOON...ESPECIALLY INTO WESTERN WISCONSIN. THE ONLY INHIBITING FACTOR FOR CONVECTIVE INITIATION ALONG THE FRONT APPEARS TO BE RATHER WEAK SURFACE CONVERGENCE..WITH WINDS S-SW ALONG THE BOUNDARY. THE HIRES MODELS ARE SHOWING RATHER ROBUST CONVECTION DEVELOPING ALONG THE BOUNDARY AS IT MOVES INTO EASTERN MINNESOTA FRIDAY AFTERNOON. WILL HAVE TO MONITOR THIS SITUATION INTO FRIDAY...AS SEVERE WEATHER THREAT IS FORECAST TO BE LOW AT THIS TIME. FRONT EXITS TO THE EAST FRIDAY NIGHT TAKING THE HEAVY CONVECTIVE POTENTIAL WITH IT. THIS WILL LEAVE THE UPPER LOW OVER THE AREA THROUGH AT LEAST SATURDAY. SHOWERS LOOK TO BE A FAIR BET ESPECIALLY LATER IN THE DAY AS THE LOW MOVES EAST. WITH ABUNDANT CLOUD COVER...WILL BE LITTLE IN THE WAY OF HEATING...SO CONVECTIVE POTENTIAL IS LOW. CLEARING SHOULD MOVE INTO THE AREA LATER SATURDAY NIGHT...AND SUNDAY LOOKS LIKE THE BEST DAY OF THE WEEKEND...WITH SUNSHINE AND MILD TEMPERATURES. THE EXTENDED PORTION OF THE FORECAST STARTS OFF RATHER COOL...ESPECIALLY OVER THE EASTERN CWA MONDAY MORNING. THERE MAY EVEN BE A FROST POTENTIAL OVER A PORTION OF WEST CENTRAL WISCONSIN. THE NEXT WEATHER SYSTEM MOVES INTO THE AREA LATER MONDAY WITH SOME SHOWERS INTO THE WESTERN CWA. THE 00Z GFS AND ECMWF DIVERGE SOMEWHAT ON THE OVERALL EVOLUTION AND MOVEMENT OF THE NEXT LOW PRESSURE SYSTEM THAT MOVES ACROSS THE NORTHERN STATES THROUGH MUCH OF NEXT WEEK. IT DOES APPEAR THE THREAT OF MORE SHOWERS AND THUNDERSTORMS RETURNS BY MIDWEEK...WITH TEMPERATURES REMAINING BELOW NORMAL THROUGH THE PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1248 PM CDT THU MAY 30 2013 SCATTERED SHOWERS AND THUNDERSTORMS...POSSIBLY STRONG...WILL PLAGUE THE WI TAF SITES THIS AFTERNOON AND EARLY EVENING...WITH WIDELY SCATTERED NON-SEVERE ACTIVITY TO THE WEST OVER MN. CIGS WILL REMAIN BETWEEN 2500-3500 FT THROUGHOUT...WITH THE POTENTIAL FOR IFR VSBYS ATTENDANT WITH ANY SHOWERS/TS THAT AFFECT SITES. WINDS WILL GUST TO BETWEEN 25 AND 30 KTS THIS AFTERNOON...AND AGAIN ON FRIDAY. SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE AGAIN ON FRIDAY...BUT TIMING/COVERAGE CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAF AT THIS POINT. KMSP... SCT-BKN CLOUDS BETWEEN 2500-3500 FT WILL PREVAIL THROUGH THIS EVENING. THE MAIN WINDOW FOR SHOWERS AND POSSIBLY ISOLATED THUNDER WILL BE BETWEEN 23Z AND 04Z...THEN A BREAK IS EXPECTED BEFORE DIURNALLY DRIVEN ACTIVITY POSSIBLY DEVELOPS AGAIN ON FRIDAY. SOUTHERLY WINDS WILL GUST INTO THE UPPER 20S /KNOTS/ THIS AFTERNOON...THEN BECOME GUSTY AGAIN BY 15Z FRIDAY. /OUTLOOK FOR KMSP/ SAT...MVFR CIGS POSSIBLE. SHRA LIKELY. WINDS WNW 5-10 KTS. SUN...MVFR CIGS POSSIBLE EARLY. WINDS N 5 KTS. MON...VFR. WINDS SE 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...DWE AVIATION...LS
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
244 PM CDT THU MAY 30 2013 .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 240 PM CDT THU MAY 30 2013 TORNADO WATCH CONTINUES UNTIL 8 PM. ATMOSPHERE OUTSIDE OF OUTFLOW COOLED AIR HAS BECOME QUITE UNSTABLE WITH MLCAPES ABOVE 2000 J/KG. AT THE SAME TIME...DEEP LAYER SHEAR IS INCREASING IN RESPONSE TO APPROACHING TROUGH CURRENTLY OVER THE CENTRAL PLAINS. THIS TROUGH IS THE MAIN FOCUS FOR LARGE SCALE ASCENT TONIGHT AND CONSEQUENTLY IT WILL DETERMINE THE OVERALL PRECIPITATION TRENDS. RAP SHOWS THIS TROUGH MOVING ACROSS THE CWA AROUND 06Z...SO CURRENT THINKING IS THAT LINE OF STORMS OVER WESTERN MO WILL CONTINUE TO SLOWLY MOVE EAST ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. AFOREMENTIONED INSTABILITY AND SHEAR STILL FAVORS THE POTENTIAL FOR A FEW SUPERCELLS OR ORGANIZED MULTI-CELLS THAT COULD PRODUCE LARGE HAIL AND DAMAGING WINDS. LOW LEVEL SHEAR ALSO SUGGESTS THAT ONE OR TWO TORNADOES COULD FORM IN THE STRONGER STORMS. STILL LOOKS REASONABLE THAT WESTERN MO LINE WILL EXIT THE EASTERN COUNTIES LATER THIS EVENING. OUTFLOW FROM THE LINE WILL LIKELY STALL OVER SOUTHERN MO...SO KEPT CHANCE OF THUNDERSTORMS GOING IN THE SOUTHERN CWA INTO THE OVERNIGHT HOURS. STILL EXPECT REDEVELOPMENT OF THUNDERSTORMS OVER WESTERN MO ON THE NOSE OF THE LOW LEVEL JET OVERNIGHT THAT WILL MOVE INTO NORTHEAST AND CENTRAL MO TOWARD 12Z. FLASH FLOOD WATCH WILL CONTINUE AS IS. HEAVIEST RAINFALL WILL FOCUS OVER THE WATCH AREA TONIGHT AND THE SOUTHERN AND EASTERN COUNTIES HAVE HIGH FLASH FLOOD GUIDANCE. ATMOSPHERE IS VERY MOIST AND DEEP LAYER FLOW FAVORS TRAINING TONIGHT. .LONG TERM...(FRIDAY THROUGH NEXT THURSDAY) ISSUED AT 240 PM CDT THU MAY 30 2013 CONVECTIVE TRENDS ARE SOMEWHAT UNCLEAR FOR FRIDAY MORNING. SOME GUIDANCE SHOWS LINGERING CONVECTION ACROSS THE EASTERN OZARKS AND SOUTHERN ILLINOIS. THIS COULD BE POSSIBLE IF THE AFOREMENTIONED OUTFLOW BOUNDARY FROM THURSDAY NIGHT`S CONVECTION IS STILL IN PLACE OVER THOSE AREAS. HOWEVER...MOST OF THE GUIDANCE SHOWS A DRYING TREND BY AROUND 12Z ACROSS THE AREA. THEN...THE LOW LEVEL JET REFOCUSES BACK OVER NORTHERN/NORTHWESTERN MISSOURI. ALL GUIDANCE SHOWS A TREMENDOUS AMOUNT OF MOISTURE CONVERGENCE IN THAT AREA STARTING ABOUT 12Z AND RAIN DEVELOPING BETWEEN 12Z AND 15Z...SPREADING INTO NORTHEAST MISSOURI/WEST CENTRAL ILLINOIS PROBABLY DURING THE MID TO LATE MORNING. INSTABILITY WILL BUILD RAPIDLY DURING THE LATE MORNING WITH MUCAPE EXCEEDING 2500 J/KG ACCORDING TO MOST GUIDANCE AND DEEP LAYER SHEAR AROUND 50-60KTS SO SEVERE STORMS WILL BE POSSIBLE AT ANY TIME DURING THE LATE MORNING. HOWEVER...THE MAIN SHOW WILL LIKELY DEVELOP DURING THE LATE AFTERNOON OR EARLY EVENING AS ANOTHER LOBE OF VORTICITY WRAPS AROUND THE SOUTH SIDE OF THE UPPER LEVEL LOW AND PUSHES THE SURFACE FRONT INTO NORTHWEST MISSOURI. WHATEVER`S LEFT OF THE CAP WILL ALSO BE WIPED AWAY. AFTERNOON CAPE VALUES LOOK TO BE IN EXCESS OF 3000 J/KG WITH SHEAR STAYING ABOVE 50KTS. THINK THERE WILL BE SOME DISCRETE STORMS INITIALLY...BUT WITH LITTLE OR NO CAP AND COPIOUS CAPE WE SHOULD SEE THE STORMS CONGEAL INTO A LINE. CANNOT RULE OUT ANY KIND OF SEVERE WEATHER INCLUDING DAMAGING WINDS...LARGE HAIL...AND EVEN TORNADOES WITH THE LINE. THE LINE SHOULD PROGRESS AT A MODERATE PACE INTO SOUTHEAST MISSOURI BY EARLY MORNING SATURDAY. OF COURSE WITH THE HEAVY RAIN POTENTIAL AND NEARLY SATURATED GROUND THERE WILL BE A CONTINUING FLASH FLOOD THREAT...AND IT`S LIKELY THE FLASH FLOOD WATCH WILL NEED TO BE EXPANDED EITHER EARLY FRIDAY MORNING OR FRIDAY AFTERNOON TO COVER THE REST OF THE CWFA. CURRENT THINKING IS THAT THE INITIAL LINE OF CONVECTION WILL WEAKEN OVER THE EASTERN OZARKS SATURDAY MORNING. HOWEVER THERE WILL BE REDEVELOPMENT BY EARLY SATURDAY AFTERNOON...PERHAPS AS FAR NORTHWEST AS THE COLUMBIA AREA...AS THE SURFACE COLD FRONT FINALLY KICKS INTO GEAR AND HEADS EAST. SPC STILL HAS THE SOUTHEASTERN 2/3 OF THE CWFA IN A SLIGHT RISK SATURDAY...INCLUDING THE STL METRO AREA AND POINTS ALONG AND EAST OF THE I-44/I-55 CORRIDORS. THE UPPER LEVEL SHORTWAVE FINALLY SWINGS THROUGH SATURDAY AFTERNOON/EARLY EVENING PUSHING THE COLD FRONT SOUTHEAST INTO THE LOWER MISSISSIPPI/TENNESSEE VALLEYS. (SUNDAY THROUGH NEXT THURSDAY) HIGH PRESSURE IS STILL EXPECTED TO BUILD ACROSS THE MIDWEST SUNDAY AND CONTROL THE WEATHER AT LEAST THROUGH MONDAY. EXPECTING BELOW NORMAL TEMPERATURES AND LESS HUMID CONDITIONS THROUGH THAT PERIOD. MEDIUM RANGE GUIDANCE IS A LITTLE FASTER THAN YESTERDAY IN PUSHING THE HIGH EAST AWAY FROM THE MID-MISSISSIPPI VALLEY. SOUTHERLY FLOW RETURNS TUESDAY AND BOTH THE GFS AND ECMWF PRINT OUT PRECIP LATE TUESDAY THROUGH THURSDAY AS A SHORTWAVE DIPS INTO THE NORTHERN PLAINS. THE GFS IS MUCH MORE DYNAMIC WITH THIS WAVE THAN THE ECMWF AND THEREFORE CRANKS OUT A LOT MORE PRECIP. HAVE OPTED TO JUST STICK WITH CHANCE POPS FOR THIS PERIOD RIGHT NOW. WILL CONTINUE TO WATCH THIS NEXT WAVE AND INCREASE POPS AS NEEDED IF BOTH MODELS CONTINUE TO TREND WETTER. CARNEY && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 136 PM CDT THU MAY 30 2013 MODELS ARE UNCLEAR ON TIMING OF SHOWERS/THUNDERSTORMS FOR EACH TAF...SO AMENDMENTS WILL BE NECESSARY BASED ON RADAR TRENDS THE NEXT 12 HOURS. CURRENT THINKING IS THAT THUNDERSTORMS WILL CONTINUE OVER EASTERN MO/WESTERN IL THE NEXT FEW HOURS...AND THAT THE LINE OVER WESTERN MO WILL ADVANCE SLOWLY EASTWARD THE REST OF THE AFTERNOON AND EVENING. STORMS MAY BE SEVERE WITH STRONG WINDS GUSTS AND HAIL. EXPECT MAINLY VFR CONDITIONS EXCEPT IN THE HEAVIER CORES WHERE IFR VSBYS/CIGS CAN BE EXPECTED. SPECIFICS FOR KSTL...THUNDERSTORMS CURRENTLY AROUND LAMBERT WILL INTERMITTENTLY BRING IFR CONDITIONS IN HEAVY RAIN. CANNOT RULE OUT HAIL AND STRONG WINDS GUSTS WITH ANY OF THE STRONGER CORES. LINE OF STORMS CURRENTLY OVER WESTERN MO WILL NOT REACH KSTL UNTIL AFTER 00Z. BRITT && .PRELIMINARY POINT TEMPS/POPS... SAINT LOUIS 71 84 69 81 / 80 60 90 70 QUINCY 67 80 65 77 / 80 80 80 50 COLUMBIA 67 81 66 78 / 80 70 90 50 JEFFERSON CITY 67 82 68 78 / 80 60 90 60 SALEM 69 83 71 81 / 70 50 70 70 FARMINGTON 68 82 69 81 / 70 50 90 70 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-FRANKLIN MO-GASCONADE MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO. IL...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR ADAMS IL-BROWN IL- CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL- MONROE IL-PIKE IL-ST. CLAIR IL. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
136 PM CDT THU MAY 30 2013 .UPDATE... ISSUED AT 136 PM CDT THU MAY 30 2013 TORNADO WATCH IS IN EFFECT FOR THE ENTIRE AREA UNTIL 8 PM. MUCAPES ARE AROUND 2000 J/KG AND WILL CONTINUE TO RISE OUTSIDE OF OUTFLOW COOLED AIR THIS AFTERNOON. EFFECTIVE SHEAR HAS IS NOW AROUND 35KTS WHICH SUGGESTS THAT A FEW SUPERCELLS MAY DEVELOP THIS AFTERNOON... BUT STILL EXPECT MAINLY MULTI-CELLS CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. LOW LEVEL SHEAR IS STILL IMPRESSIVE WITH 0-1KM SHEAR BETWEEN 20-35KTS...SO A FEW BRIEF TORNADOES ARE POSSIBLE WITHIN LINES AND IN ANY SUPERCELLS. CONTINUE TO EXPECT STORMS TO DEVELOP ALONG THE LINE NEAR THE MISSISSIPPI RIVER. MAIN LINE OVER WESTERN MISSOURI WILL MOVE INTO CENTRAL MO BY MID AFTERNOON...AND NEAR THE MISSISSIPPI RIVER LATER THIS AFTERNOON/EARLY EVENING. BRITT && .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 1044 AM CDT THU MAY 30 2013 COMPLICATED FORECAST FOR THE REST OF THE DAY AS AREA OF SHOWERS/ THUNDERSTORMS ARE MOVING VERY SLOWLY EASTWARD LATE THIS MORNING. THIS IS AHEAD OF THE NEGATIVELY TILTED TROUGH CURRENTLY OVER THE CENTRAL PLAINS THAT THE RAP LIFTS INTO MO/IL THIS EVENING. LAST FEW RUNS OF THE HRRR SUPPORTS THAT THE WESTERN MO COMPLEX WILL MOVE NORTHEASTWARD INTO THE CWA BY LATE THIS AFTERNOON/EARLY THIS EVENING. IN ADDITION...SCATTERED THUNDERSTORMS HAVE RECENTLY DEVELOPED OVER SOUTH CENTRAL MO THAT ARE LIFTING NORTHEASTWARD. THESE TRENDS SUPPORT GOING FORECAST THAT PRECIPITATION CHANCES WILL INCREASE THROUGH THE AFTERNOON. MLCAPES ARE CURRENTLY 1000-1500 J/K AND SHOULD INCREASE IN THE WARM SECTOR AS TEMPERATURES CLIMB INTO THE LOWER-MID 80S. 0-6KM SHEAR WILL BE RELATIVELY WEAK WHICH FAVORS MULTICELL STORMS...THOUGH INCREASING INSTABILITY AND LARGE SCALE LIFT SUGGEST THAT THERE MAY BE A FEW SEVERE STORMS CAPABLE OF PRODUCING SOME LARGE HAIL AND DAMAGING WIND GUSTS THROUGH THIS EVENING. THE LOW LEVEL JET WILL REMAIN 40-50KTS TODAY...SO CANNOT RULE OUT A TORNADO OR TWO IN THE STRONGEST STORMS. LATEST RADAR IMAGERY HAS SHOWN THE TENDENCY FOR CELLS TO TRAIN...SO HEAVY RAINFALL DOES LOOK LIKE A REAL THREAT GIVEN PWATS AROUND 1.8 INCHES. BRITT .LONG TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 343 AM CDT THU MAY 30 2013 (TONIGHT THROUGH SATURDAY NIGHT) PCPN CHANCES INCREASE TONIGHT AS NEXT IN SERIES OF MCS/S DEVELOPS OVER WESTERN MO AND SLIDES EAST THROUGH FORECAST AREA...WITH BEST CHANCES OF HEAVY RAIN ALONG AND NORTH OF I-70. SINCE THIS AREA HAS HAD QUITE A BIT OF RAIN OVER THE PAST WEEK AND SOILS REMAIN SATURATED...HAVE ISSUED A FLASH FLOOD WATCH FROM 18Z TODAY THROUGH 12Z SATURDAY. LOWS TONIGHT TO REMAIN MILD...IN THE MID 60S TO LOW 70S. FOR FRIDAY...A LOT WILL DEPEND ON HOW SOON THIS AREA OF STORMS WEAKENS/EXITS FORECAST AREA...ON WHAT WILL DEVELOP FOR THE AFTERNOON AND EVENING HOURS. IF ATMOSPHERE GETS WORKED OVER...IT WILL TAKE A LOT FOR IT TO RECOVER. FOR NOW...WILL ERR ON THE SIDE OF CAUTION WITH STORMS REDEVELOPING BY THE AFTERNOON HOURS AS NEXT SHORTWAVE SLIDES THROUGH. WITH DECENT INSTABILITY...MID LEVEL LAPSE RATES AND STRENGTHENING LOW LEVEL JET...WILL SEE A CHANCE FOR SEVERE WEATHER ONCE AGAIN FRIDAY AFTERNOON AND OVERNIGHT. ANOTHER ROUND OF HEAVY RAIN IS POSSIBLE AS WELL...WHICH WILL EVENTUALLY SHIFT TO THE SOUTH WITH TIME. SO MAY NEED TO EXTEND FLASH FLOOD WATCH TO INCLUDE REST OF FORECAST AREA. MAIN COLD FRONT TO FINALLY MOVE THROUGH THE AREA DURING THE DAY ON SATURDAY WITH LAST IN A SERIES OF SHORTWAVES SLIDING THROUGH...SO PCPN TO TAPER OFF BY SATURDAY EVENING. (SUNDAY THROUGH NEXT WEDNESDAY) COOLER AND DRIER WEATHER IS IN STORE FOR THE LAST PART OF THE WEEKEND AND INTO EARLY NEXT WEEK. HIGHS WILL BE IN THE UPPER 60S TO MID 70S SUNDAY THROUGH TUESDAY. THEN NEXT WEATHER SYSTEM TO APPROACH THE REGION BY MID WEEK WITH NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS BEGINNING TUESDAY NIGHT. BYRD && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 136 PM CDT THU MAY 30 2013 MODELS ARE UNCLEAR ON TIMING OF SHOWERS/THUNDERSTORMS FOR EACH TAF...SO AMENDMENTS WILL BE NECESSARY BASED ON RADAR TRENDS THE NEXT 12 HOURS. CURRENT THINKING IS THAT THUNDERSTORMS WILL CONTINUE OVER EASTERN MO/WESTERN IL THE NEXT FEW HOURS...AND THAT THE LINE OVER WESTERN MO WILL ADVANCE SLOWLY EASTWARD THE REST OF THE AFTERNOON AND EVENING. STORMS MAY BE SEVERE WITH STRONG WINDS GUSTS AND HAIL. EXPECT MAINLY VFR CONDITIONS EXCEPT IN THE HEAVIER CORES WHERE IFR VSBYS/CIGS CAN BE EXPECTED. SPECIFICS FOR KSTL...THUNDERSTORMS CURRENTLY AROUND LAMBERT WILL INTERMITTENTLY BRING IFR CONDITIONS IN HEAVY RAIN. CANNOT RULE OUT HAIL AND STRONG WINDS GUSTS WITH ANY OF THE STRONGER CORES. LINE OF STORMS CURRENTLY OVER WESTERN MO WILL NOT REACH KSTL UNTIL AFTER 00Z. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-FRANKLIN MO-GASCONADE MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO. IL...FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR ADAMS IL-BROWN IL- CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL- MONROE IL-PIKE IL-ST. CLAIR IL. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1200 PM MDT THU MAY 30 2013 .AVIATION... 18Z TAF CYCLE WITH A POTENT UPPER LEVEL JET STRETCHED OVER NORTHERN NEW MEXICO...ANOTHER AFTERNOON OF GUSTY WEST TO NORTHWEST WINDS WILL PREVAIL ACROSS THE FORECAST AREA...FAVORING THE NORTHERN HIGH TERRAIN...ADJACENT EAST SLOPES...EASTERN HIGHLANDS AND NORTHEAST PLAINS. SATELLITE WV IMAGERY DEPICTS MOUNTAIN WAVES IN THE NORTHEAST THIRD OF THE FORECAST AREA. SURFACE WINDS WILL GUST TO 35-40KTS ACROSS THE NORTH AND KABQ WILL BE MONITORED FOR A POTENTIAL AWW ISSUANCE...TAF IS CURRENTLY CARRYING GUSTS JUST BELOW CRITERIA. BLOWING DUST COULD RESTRICT VISIBILITIES TO 3-5SM CENTRAL AND EASTERN LOCATIONS. WINDS WILL GRADUALLY RELAX AFTER 03Z...AND WILL START TO INCREASE AFTER 15Z ON FRIDAY WITH SOMEWHAT LOWER MAGNITUDES THAN THOSE OF TODAY. WITH THE EXCEPTION OF AREAS IMPACTED BY BLOWING DUST...VFR CONDITIONS EXPECTED ALL AREAS. 05 && .PREV DISCUSSION...325 AM MDT THU MAY 30 2013... DRYLINE HAS SO FAR STAYED TO THE EAST OF NEW MEXICO THIS MORNING AND ALTHOUGH IT/S FAIRLY CLOSE TO HOBBS DON/T EXPECT IT TO GET MUCH FARTHER WEST IF AT ALL. IN THE NORTHEAST DEWPOINTS HAVE COME UP AS THE SFC LOW SHIFTED INTO THE TX/OK PANHANDLES BUT THIS INCREASE LIKELY WON/T LAST LONG WITH THE RUC FORECASTING A WEAK SFC LOW TO REDEVELOP OVER SE CO BY MIDDAY. MODELS ALSO SHOW CURRENT BATCH OF MID LEVEL MOISTURE EXITING BY MIDDAY. UPPER JET TO RETREAT NWD TODAY BUT WILL BE STRETCHED OVER FAR NRN NM AND COLORADO...COMBINED WITH THE SFC LOW PLACEMENT WILL HAVE LOW END WIND ADVY OVER SOME OF THE NORTH CENTRAL/NORTHEAST SOUTH TO CLINES CORNERS. DRY INTO FRIDAY NIGHT. ANOTHER WINDY DAY ON FRIDAY WITH CRITICAL FIRE WX CONDITIONS POSSIBLE. ANOTHER BATCH OF MID LEVEL MOISTURE PASSES OVERHEAD TONIGHT AND FRIDAY BUT ANYTHING MORE THAN A FEW SPRINKLES OUT OF IT...IF THAT...WOULD BE A SURPRISE. SURFACE FRONT PUSHES THROUGH FRIDAY NIGHT WITH THE BACK DOOR FRONT INTO THE EAST SATURDAY. LOW LEVEL MOISTURE APPEARS TO MOVE IN FROM THE SOUTH AND SOUTHEAST WITH INCREASING INSTAB SO WENT AHEAD AND SPREAD SOME SMALL POPS FROM THE EAST SLOPES OF THE SOUTH CENTRAL MOUNTAIN ACROSS CHAVES COUNTY AND NORTHEAST ALONG THE TX BORDER SATURDAY AFTERNOON ALTHOUGH FOR NOW BEST CONFIDENCE IS IN THE SOUTHEAST. ANOTHER BLOB OF MID LEVEL MOISTURE TO MIGRATE OVER THE SOUTHERN HALF OF THE STATE AND COULD NOT RULE OUT A FEW SPRINKLES UNDERNEATH IT...BUT LEFT MENTION OUT OF FCST FOR NOW. IN FACT THE ADJMET GUIDANCE DOES PAINT SOME LOW POPS OVER THE SOUTHWEST MTS. INCREASED POPS SOMEWHAT SUNDAY ESPECIALLY ALONG THE CENTRAL MT CHAIN. LEFT THE MENTION OF DRY CONVECTION FROM THE RGV WWD ALTHOUGH COULD BE A MIX WITH AT LEAST SOME MEAGER MEASURABLE PCPN DEPENDING IF THE SURGE IS AS STRONG AS DEPICTED SO FAR. HOWEVER...MONDAY STARTS TO DRY OUT AND TUESDAY EVEN MORE SO. REMOVED THE POPS IN THE EAST FOR TUESDAY NIGHT...AND PROBABLY SHOULD HAVE FOR TUESDAY AS WELL AS RIGHT NOW IT LOOKS DRY. ANOTHER BACKDOOR FRONT WEDNESDAY LOOKS TO PUSH INTO THE RGV WEDNESDAY NIGHT...SO POPS/WX GRIDS FOR MID TO LATE WEEK HAVE BEEN UPDATED. .FIRE WEATHER... ...WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS DUE TO STRONG WIND AND LOW HUMIDITY FOR MUCH OF NORTHERN AND CENTRAL NEW MEXICO THROUGH FRIDAY... ...DRY LIGHTNING THREAT INCREASING SUNDAY CENTRAL/WEST... MOVING INTO DAY 2 OF A PROTRACTED CRITICAL FIRE WEATHER PATTERN THAT WILL EXTEND THROUGH FRIDAY. THEREAFTER...FAR LESS WIND BUT GROWING CONFIDENCE IN A SUBSTANTIAL WESTERLY PUSH OF LOWER LEVEL MOISTURE THAT WILL RESULT IN A SIGNIFICANT DRY LIGHTNING THREAT FOR CENTRAL/WESTERN AREAS BY SUNDAY. SATURDAY LOOKS TO BE A CLASSIC TRANSITION DAY AS RICHER LOW LEVEL MOISTURE INITIALLY MAKES A RETURN TO THE EC/SE PLAINS AS SURFACE WINDS VEER TO SELY AND TAPS INTO A NOW SEMI-PERMANENT POOL OF GULFMEX MOISTURE. POTENTIAL FOR SOME DRIER STORMS ALONG THE EAST SLOPES OF THE CENTRAL/SC MOUNTAIN SATURDAY PM. HIGHER DEW POINT AIR ALSO CREEPING NORTHWARD ALONG THE RGV AND THAT COUPLED WITH A SUBTLE AND ALWAYS SNEAKY UPTICK IN MID-LEVEL MOISTURE AS THE UPPER RIDGE EXPANDS/BUILDS NORTHWARD COULD RESULT IN AT LEAST AN ISOLATED DRY LIGHTNING THREAT OVER THE WC/SW HIGHER TERRAIN AS EARLY AS SATURDAY AFTERNOON OR EVENING. THIS WILL BE CLOSELY MONITORED. EVEN THE SLIGHTEST UPTICK IN LOWER/MID LEVEL MOISTURE IN THE PRESENCE OF VERY STEEP LAPSE RATES THAT ARE TYPICAL OF THE DEVELOPING PATTERN THIS WEEKEND SEEMS TO RESULT IN MORE THAN EXPECTED BUILDUPS/VIRGA AND DRY CG/S. WE SHALL SEE. SUNDAY AFTERNOON/EVENING LOOKING TO BE THE MORE CRITICAL DAY WITH RESPECT TO DRY LIGHTNING FOR THE WEST THOUGH MONDAY COULD BE FAIRLY ACTIVE EAST OF THE DIVIDE TO THE EAST SLOPES OF THE CENTRAL MOUNTAIN CHAIN AS DRIER AIR ADVANCES EASTWARD. IN THE MEANTIME...LARGE-SCALE UPPER TROUGH SLOWLY PIVOTING NORTHEAST FROM THE CENTRAL/NORTHERN ROCKIES EARLY THIS MORNING. BASE OF THE TROUGH TRANSLATED EASTWARD OVER OUR AREA THIS PAST NIGHT AND PRESENT INDICATIONS ARE THAT THE STRONGEST MID-LEVEL WINDS WILL PASS OVERHEAD BEFORE MIDDAY. THAT SAID...AN ANOMALOUSLY STRONG UPPER LEVEL JET ORIENTED NW TO SE FROM THE GREAT BASIN TO THE FOUR CORNERS REGION WILL NOT SHIFT NORTHWARD APPRECIABLY TODAY. AS A RESULT...WIND SPEEDS THOUGH A BIT LESS THAN YESTERDAY WILL STILL BE SIGNIFICANT WITH FREQUENT GUSTS OF 35-40 MPH ACROSS THE NORTH. SURFACE LOW NOT AS FAVORABLE EITHER. NO CHANGES TO THE FIRE WEATHER WATCH FOR FRIDAY THOUGH BELT OF STRONGEST WINDS DO SHIFT SOUTHWARD PER PREVIOUS FORECAST. VERY DEEP MIXING CONTINUES TODAY BEFORE MAX MIXING HEIGHTS TREND DOWNWARD SLIGHTLY ON FRIDAY. LOWEST RH VALUES CENTRAL VALLEY CORRIDOR AND IN THE EAST. EXTENDED MODELS STILL TRENDING DRIER/BREEZIER EARLY NEXT WORK WEEK FOLLOWING OUR LIGHTNING PERIOD. BACK TO VERY DEEP MIXING AND GUSTY AFTERNOON/EVENING PERIODS THOUGH TOO EARLY TO GAUGE STRENGTH OF ANY SUSTAINED WINDY PERIODS. KJ && .ABQ WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ101>104-106>108. FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR THE FOLLOWING ZONES...NMZ101>108. WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES... NMZ510>516-523-527>529. && $$ 50
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1257 PM CDT THU MAY 30 2013 .UPDATE... ISSUED AT 1256 PM CDT THU MAY 30 2013 EARLY AFTERNOON UPDATE FOCUSES ON FINE TUNING POP TRENDS FOR MAINLY THE SOUTH...WHERE THERE HAS BEEN ONLY ISOLATED SHOWERS THROUGH THE DAY AFTER RECEIVING 3 TO 5 INCHES OVERNIGHT. SKIES ARE CLEARING IN THE REGION...AND THEREFORE LIKING THE NAM SOLUTION WHICH IS SLIGHTLY MORE UNSTABLE FOR LATE THIS AFTN INTO THE EVENING. STILL THINK THERE IS A GOOD CHANCE FOR SCATTERED TSTMS IN THE 21Z TO 03Z TIMEFRAME AND WILL MAINTAIN 30 TO 40 POPS. ALSO UPDATED FOR NEW AVIATION DISCUSSION. UPDATE ISSUED AT 1000 AM CDT THU MAY 30 2013 MORNING UPDATE FOCUSES ON FLOODING IN CLAY COUNTY MINNESOTA AND POP TRENDS. RADAR CONTINUES TO SHOW A BAND OF SHOWERS ACROSS NORTHWESTERN ZONES. INCREASED POPS IN THIS REGION AND DECREASED POPS ACROSS THE SOUTHERN HALF OF THE CWA. HRRR DOES SHOW REDEVELOPMENT OVER SOUTHEASTERN ZONES SO MAINTAINED LIKELIES...HOWEVER WENT DOWN TO 30 POPS FOR SOUTHEASTERN ND AND SOUTHERN VALLEY. WILL WAIT TO FURTHER ASSESS 12Z RUN BEFORE CHANGING ANYTHING BEYOND 00Z FRIDAY. REPORTS OF FIVE TO SEVEN INCHES ARE COMING IN ALONG THE BUFFALO RIVER BASIN TO INCLUDE THE CITIES OF AVERILL AND DILWORTH. WILL EXTEND WARNING AREA IN TIME BUT CHOP OFF CASS COUNTY AND NORMAN COUNTY...WHERE RADAR ESTIMATES ARE ABOUT FOUR INCHES OR LESS WITH NO REPORTS OF OVERLAND FLOODING FROM THOSE COUNTY MANAGERS. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 355 AM CDT THU MAY 30 2013 THE MAIN CHALLENGE WILL BE SHOWER AND THUNDERSTORM CHANCES INTO FRIDAY AND HEAVY RAIN POTENTIAL. THE MODELS ARE IN GOOD OVERALL AGREEMENT BUT NOT PICKING UP TOO WELL ON MESOSCALE FEATURES. FOR TODAY AND TONIGHT...EXPECT SHOWERS AND STORMS TO LIFT TO THE NORTH AND LIKELY BECOME MORE FOCUSED IN THE NORTHERN AREAS. THERE WILL BE A CHANCE FOR LOCALLY HEAVY RAINFALL NEAR ANY STORMS...GIVEN PWATS OVER 1.5 INCHES. THERE COULD BE SOME STRONGER STORMS THIS AFTERNOON IF SFC HEATING OCCURS...BUT I AGREE WITH SPC IN KEEPING JUST 5% PROBS FOR HAIL/WIND AND NO SLIGHT RISK AT THIS TIME. THINK THE MAIN ISSUE COULD BE HEAVY RAIN IF TRAINING ECHOES DEVELOPS. HARD TO PINPOINT WHERE THIS MAY OCCUR...SO NO FLOOD HEADLINES PLANNED...ALTHOUGH THERE COULD BE MORE FLOODING ISSUES NEAR PERSISTENT HEAVY RAIN TODAY AND TONIGHT. FOR FRIDAY...THE UPPER LOW WILL SLOWLY MOVE INTO THE AREA FROM THE WEST AND EXPECT MORE WRAPAROUND SHOWERS AND SOME THUNDER. AGAIN LOCALLY HEAVY RAINFALL IS POSSIBLE NEAR STRONGER SHOWERS AND STORMS. IT WILL BE COOLER THAN TODAY WITH WINDS SHIFTING TO THE NORTH BY AFTERNOON IN ALL BUT THE SOUTH AND EASTERN AREAS. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 355 AM CDT THU MAY 30 2013 FOR FRI NIGHT INTO SAT...WRAPAROUND SHOWERS WILL CONTINUE BEFORE IT DRIES OUT BY SAT AFTERNOON. FOR SUNDAY THROUGH WEDNESDAY...EXPECT A LOW AMPLITUDE LONG WAVE TROUGH OVER THE NORTHERN PLAINS TO SHIFT EAST. ECMWF AND GFS GENERALLY AGREE TIMING WISE HOWEVER THE GFS IS A HIGHER AMPLITUDE SOLUTION COMPARED TO THE ECMWF. WILL BLEND THE MODELS. ECMWF HAS SLOWED DOWN FROM MODEL RUN TO MODEL RUN WHILE THE GFS HAS SHIFTED PRECIP SOUTH WITH EACH RUN. WILL SLOW DOWN PRECIP FOR TUE AND DECREASE POPS A BIT FOR MON AND MON NIGHT. LITTLE CHANGE TO TEMPS FOR SUN THROUGH TUE. WED HIGH TEMP WAS INCREASED BY 3 DEGREES IN THE NORTHWEST ZONES AND A DEGREE OR TWO LOWER IN THE SOUTHERN ZONES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1256 PM CDT THU MAY 30 2013 COMPLEX SITUATION AS AN UPPER LOW MOVES ACROSS THE NORTHERN PLAINS. MOST LOCATIONS HAVE HAD MVFR CEILINGS WITH SCATTERED SHOWERS MOVING ACROSS THE FORECAST AREA. KEPT MOSTLY MVFR CEILINGS WITH VCSH OR -SHRA BUT THERE COULD BE SOME IMPROVEMENTS TO VFR OR DROPS TO IFR AT TIMES. VIS SHOULD ONLY BE LIMITED WHEN SHOWERS MOVE OVER. SOME THUNDERSTORMS AND CB ARE ALSO POSSIBLE...MAINLY IN THE KFAR AREA DURING THE LATE AFTERNOON AND EVENING. WINDS ACROSS THE NORTHWESTERN FORECAST AREA WILL SHIFT TO THE NORTH AS THE SFC LOW BEGINS TO MOVE EAST AND A COLD FRONT MOVES INTO THE AREA. AHEAD OF THE FRONT WINDS WILL REMAIN OUT OF THE SOUTH AND EAST. THINK THAT MOST LOCATIONS WILL BE MVFR OR IFR CEILINGS AND MVFR VIS WITH SCATTERED RAIN SHOWERS THROUGH THE EARLY MORNING HOURS. SOME IMPROVEMENT IS POSSIBLE TOWARDS THE END OF THE TAF PERIOD. && .HYDROLOGY... ISSUED AT 1256 PM CDT THU MAY 30 2013 A BAND OF HEAVY RAIN FELL OVERNIGHT FROM FARGO THROUGH NORTHEASTERN CLAY COUNTY...WITH AMOUNTS GENERALLY RANGING FROM TWO TO FOUR INCHES. REPORTS OF OVERLAND FLOODING IN THE VICINITY OF AVERILL AND DILWORTH HAVE PROMPTED AN EXTENSION OF THE AREAL FLOOD WARNING THROUGH 03Z FRIDAY. CASS COUNTY ND AND NORMAN COUNTY MN WERE REMOVED FROM WARNING AREA AS THE THREAT OF OVERLAND FLOODING HAS ENDED IN THOSE AREAS. OTHERWISE...FLOWS FROM THE HEAVY RAIN OVERLAND AND INTO DITCHES AND STREAMS HAS WORKED ITS WAY INTO THE BUFFALO AND WILD RICE RIVERS...PROMPTING A NEW RIVER FLOOD WARNING FOR THE WILD RICE RIVER AT HENDRUM AFFECTING NORMAN COUNTY AND A CONTINUATION OF THE RIVER FLOOD WARNING AT THE BUFFALO RIVER NEAR DILWORTH AFFECTING CLAY COUNTY. SOME POINTS ON THE MAINSTEM RED RIVER AND A FEW TRIBUTARIES ARE PROGGED TO RISE TO ACTION STAGE...AND ANTICIPATED PCPN IS NOT EXPECTED TO AFFECT FORECAST LEVELS FOR NOW. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...SPEICHER SHORT TERM...DK LONG TERM...HOPPES/DK AVIATION...JR HYDROLOGY...HOPKINS
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1240 PM CDT THU MAY 30 2013 .UPDATE... ISSUED AT 1127 AM CDT THU MAY 30 2013 WINDS IN NORTHEAST NEBRASKA INTO SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA REMAIN PRIMARILY SOUTHWEST THIS MORNING KEEPING A RELATIVELY DRY LOW TO MID LEVELS UPSTREAM. WINDS ARE EXPECTED TO BACK A BIT THIS AFTERNOON WITH THE ARRIVAL OF THE SURFACE TROUGH CURRENTLY SWINGING THROUGH SOUTH CENTRAL SOUTH DAKOTA. WITH DAYTIME HEATING EARLY THIS AFTERNOON...SHOWERS AND THUNDERSTORMS SHOULD REDEVELOP ACROSS THE AREA AND TRACK EASTWARD. SHEAR IS NOT VERY IMPRESSIVE AT THIS POINT...BUT THE LATEST RAP FORECAST SOUNDINGS SUGGEST THAT WE MAY DESTABILIZE ENOUGH FOR SOME NARROW CAPE VALUES APPROACHING 1000 J/KG BY LATE AFTERNOON. CANNOT RULE OUT THE POTENTIAL FOR A FEW MARGINALLY SEVERE STORMS THIS AFTERNOON AND EVENING IN FAR SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA...WHERE MUCH MORE FAVORABLE SHEAR IS EXPECTED TO SET UP AND MOISTURE IS MORE FAVORABLE WITH SOUTHERLY WINDS. THE MAIN THREAT WITH STRONG TO SEVERE STORMS WILL BE DIME TO QUARTER- SIZE HAIL. SEVERE OUTLOOK HOWEVER IS VERY CONDITIONAL AND OVERALL NOT VERY IMPRESSIVE. MADE A QUICK UPDATE TO REMOVE POPS THIS MORNING AND ADJUST CLOUDS SLIGHTLY. EVERYTHING ELSE IS ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT THU MAY 30 2013 WILL GO AHEAD AND CANCEL THE FLASH FLOOD WATCH FOR OUR SOUTHEASTERN ZONES. REMNANTS OF LIGHT TO SPOTTY MODERATE RAINFALL ARE MOVING NORTHWARD AT THIS TIME EAST OF I 29...BUT IT IS NOT ENOUGH TO EXAGGERATE ANY EXISTING FLOODING PROBLEMS. IT IS LIKELY THAT THE HEAVIEST RAINFALL FOR TODAY WILL ALSO STAY TO THE SOUTH OF THE SIOUX FALLS FORECAST AREA. SYNOPTIC SITUATION SHOWS A HUGE UPPER LOW IN TWO PIECES...GENERALLY EXTENDING FROM OFF THE BRITISH COLUMBIA COAST TO THE NORTHWESTERN PLAINS. LARGE AREA OF SURFACE LOW PRESSURE FOLLOWS SUIT AND IS SITUATED OVER CENTRAL SD...WITH TROUGHING NUDGING DOWN INTO THE CENTRAL PLAINS. ANOTHER SURFACE LOW IS SITUATED OVER THE OKLAHOMA PANHANDLE...WHICH IS THE RESULT OF A VERY STRONG SHORTWAVE MOVING EASTWARD FROM THAT AREA TODAY...INTO KANSAS...MISSOURI...SOUTHERN IOWA AREAS. THERE IS A LOT OF MODEL CONSENSUS THAT THE HEAVIER RAIN WILL BE CONFINED TO THAT SHORT WAVE AND SOUTH OF OUR AREA. SO FROM HERE AND OUT...WE ARE MAINLY LEFTOVER WITH ISOLATED TO SCATTERED INSTABILITY SHOWERS AND A FEW POSSIBLE THUNDERSTORMS... ESPECIALLY THIS AFTERNOON. WENT DRY FOR OUR WESTERN ZONES THIS MORNING AS THERE IS SIMPLY NO SIGN OF CONVECTIVE REDEVELOPMENT YET IN CENTRAL NEB. THE 850MB STREAMLINES PRETTY MUCH TELL THE STORY FOR NOW...IN THAT THEY ARE WRAPPING FROM A WESTERLY DIRECTION UNDERNEATH THE AFOREMENTIONED LOW...COMING OUT OF WESTERN AND CENTRAL NEBRASKA AND INTO OUR WESTERN ZONES. SO THE MOIST LOW LEVEL FLOW IS CUTOFF IN OUR WEST. ALONG AND EAST OF I 29...THE LOW LEVEL JET STILL EXISTS BUT IS WEAKER THEN YESTERDAY. ML CAPE IS PRETTY ANEMIC THIS MORNING...BUT DOES INCREASE THIS AFTERNOON AS ANY CLEARING WILL HELP TO HEAT THINGS OUT. IN ADDITION...SOME OF THE HIGHER RESOLUTION MODELS ARE STRONGLY HINTING AT THE SURFACE TROUGH MOVING EASTWARD INTO THE JAMES RIVER VALLEY THIS AFTERNOON...WITH A DRY LINE PRESSING THROUGH OUR SOUTH CENTRAL SD ZONES. THE TROUGH MAY PROVIDE A FOCUS FOR SCATTERED SHOWERS AND STORMS ALONG AN AXIS FROM YANKTON TO SIOUX FALLS AND VICINITIES... HELPED BY STRONGLY VEERING PROFILES JUST AHEAD OF THE DRY LINE. ELSEWHERE AS THE AFTERNOON PROGRESSES...POPCORN TYPE INSTABILITY SHOWERS AND THUNDERSTORMS SHOULD DOMINATE THIS AREA OF THE SCATTERED VARIETY. SO VERY MUCH A NUISANCE SITUATION. HIGHS TODAY STILL LOOK LIKE WIDESPREAD 70S...WHICH SHOULD BE ENOUGH TO PROVIDE SOME AFTERNOON INSTABILITY. FOR TONIGHT...ONCE THE HEATING SUBSIDES...SO WILL OUR CHANCE FOR INSTABILITY RAINFALL. BUT LATE TONIGHT...THE UPPER LOW BEGINS TO WRAP IN A CHANCE FOR SHOWERS INTO OUR NORTHWEST AREAS. MOISTURE PROFILES IN THAT AREA ARE QUITE HIGH BY LATE TONIGHT...WITH DRY SLOTTING TAKING OVER AFTER MIDNIGHT FOR THE REST OF OUR FORECAST AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 359 AM CDT THU MAY 30 2013 ON FRIDAY AND SATURDAY...OUR WEATHER WILL CONTINUE TO BE DOMINATED BY THE UPPER LOW. IT WILL STILL BE CLOSED ON FRIDAY AS IT MOVES SLOWLY EASTWARD. THEN IT WILL BECOME A TROUGH ON SATURDAY AS IT MOVES INTO THE NORTHERN MISSISSIPPI VALLEY. PV IS VERY STRONG ON THE NORTH AND WEST SIDES OF THE UPPER LOW...ALONG WITH STRONG TROWALING CLEARLY EVIDENT AT THE MID LEVELS. ALL OF THIS IS CAUSING A HIGH MOISTURE PROFILE WHICH MOVES SOUTHEASTWARD...SO EXPECT LIGHT SHOWERS LIKELY TO MOVE IN THAT DIRECTION THROUGH TIME AND EVENTUALLY ENCOMPASSING ALMOST THE ENTIRE WESTERN HALF OF OUR FORECAST AREA. MODELS ARE CERTAINLY SHOWING QUITE A CONVEYOR BELT OF PRECIPITATION...MOVING NORTHEASTWARD AHEAD OF THE LOW FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES...THEN LIGHT RAIN ARCHING BACK THROUGH PARTS OF THE NORTHERN AND WESTERN PLAINS ALONG THE TROWALING. ANOTHER THING TO WATCH FOR FRIDAY AFTERNOON...IS THAT THE LEADING EDGE OF THE COLD FRONT COULD SPARK SOME SCATTERED THUNDERSTORMS ALONG AND SOUTH OF A SIOUX CITY TO WINDOM MN LINE. DO NOT THINK THE COVERAGE OF STORMS WILL BE ALL THAT GREAT...AND ALMOST WENT ISOLATED. BUT AGAIN SOMETHING TO WATCH FOR. THIS COLD FRONT MOVES EASTWARD AND WILL GIVE OUR FORECAST AREA SOME VERY CHILLY AIR TO CONTEND WITH ON SATURDAY. SATURDAY DOES NOT LOOK LIKE A PLEASANT DAY...AS EVEN IF LIGHT SHOWERS DO NOT OCCUR AT YOUR LOCATION...IT WILL BE CONSIDERABLY CLOUDY AND WINDY ALONG WITH THE VERY CHILLY TEMPERATURES. RECORD LOW HIGHS ON JUNE 1 ARE QUITE A BIT COLDER THAN WHAT WE HAVE FORECAST HOWEVER...SO THEY SHOULD NOT BE IN JEOPARDY OF FALLING. SOME OF THE LIGHT SHOWERS BY SATURDAY AFTERNOON WILL BE THE RESULT OF WHAT HEATING THERE IS. THEREFORE BY SATURDAY NIGHT...ELIMINATED ALL POPS IN OUR EASTERN ZONES. CONCERNING TEMPERATURES...COOLED OFF OUR WESTERN ZONES A FAIR AMOUNT ON FRIDAY BEHIND THE COLD FRONT...NOTING THE CLOUDY AND SHOWERY CONDITIONS. THE SUNDAY THROUGH WEDNESDAY PERIOD WILL START DRY AND COOL SUNDAY...BUT THE COOL WILL FEEL NICE WITH LIGHT TO MODERATE NORTHERLY WINDS BEGINNING TO TURN EASTERLY AS SURFACE RIDGE PASSES BY TO THE NORTH. WAS LOOKING FOR MONDAY TO BE DRY AND A LITTLE WARMER...BUT IT LOOKS LIKE SOUTHEASTERLY THERMAL LIFT PATTERN WILL DEVELOP SOON ENOUGH TO MENTION A SMALL CHANCE OF STORMS. THIS CHANCE SHOULD BE SOMEWHAT BIGGER FOR THE REST OF THE PERIOD...MONDAY NIGHT INTO WEDNESDAY...AS UPPER WAVE DIGS FROM SOUTHWEST CANADA INTO THE DAKOTAS. WILL GO WITH GUIDANCE KEEPING TEMPERATURES FAIRLY CLOSE TO SEASONAL FOR NOW...THIS SEEMS IN LINE WITH THE NEW ECMWF. THE GFS WOULD SUGGEST COOLER BY WEDNESDAY. SINCE NO TREND IS SEEN AS TO WHICH MODEL IS BETTER THAT FAR AHEAD...GUIDANCE AND CONSISTENCY WIN FOR NOW. FOR THE MOMENT DO NOT EXPECT MOISTURE INFLOW TO BE ENOUGH FOR SEVERE STORMS OR HEAVY RAIN...BUT MID AND UPPER FLOW WILL BE MORE THAN AMPLE SO WILL HAVE TO BE OPEN TO POSSIBLE CHANGE OF THINKING IN COMING DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1233 PM CDT THU MAY 30 2013 VFR CONDITIONS WILL BE PREDOMINATE FOR MOST AREAS...HOWEVER BRIEF DIPS TO 1500 TO 3000 FEET IN SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THROUGH AROUND 03Z FRIDAY. LEFT OUT MENTION OF SHOWERS AND THUNDERSTORMS IN TAFS AS ACTIVITY WILL BE VERY SPOTTY AND LIKELY VERY BRIEF. THE FAR NORTHWEST CORNER OF THE FORECAST AREA...INCLUDING KHON COULD DROP TO MORE PREDOMINATE MVFR CEILINGS AFTER 09Z...BUT GUIDANCE REMAINS A BIT UNCERTAIN WITH THE TIMING OF THESE LOWER CEILINGS. WINDS WILL ALSO TURN MORE SOUTHWESTERLY TONIGHT AND BECOME BREEZY DURING THE DAYLIGHT HOURS. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE... SHORT TERM...MJF LONG TERM...MJF/WILLIAMS AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1127 AM CDT THU MAY 30 2013 .UPDATE... ISSUED AT 1127 AM CDT THU MAY 30 2013 WINDS IN NORTHEAST NEBRASKA INTO SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA REMAIN PRIMARILY SOUTHWEST THIS MORNING KEEPING A RELATIVELY DRY LOW TO MID LEVELS UPSTREAM. WINDS ARE EXPECTED TO BACK A BIT THIS AFTERNOON WITH THE ARRIVAL OF THE SURFACE TROUGH CURRENTLY SWINGING THROUGH SOUTH CENTRAL SOUTH DAKOTA. WITH DAYTIME HEATING EARLY THIS AFTERNOON...SHOWERS AND THUNDERSTORMS SHOULD REDEVELOP ACROSS THE AREA AND TRACK EASTWARD. SHEAR IS NOT VERY IMPRESSIVE AT THIS POINT...BUT THE LATEST RAP FORECAST SOUNDINGS SUGGEST THAT WE MAY DESTABILIZE ENOUGH FOR SOME NARROW CAPE VALUES APPROACHING 1000 J/KG BY LATE AFTERNOON. CANNOT RULE OUT THE POTENTIAL FOR A FEW MARGINALLY SEVERE STORMS THIS AFTERNOON AND EVENING IN FAR SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA...WHERE MUCH MORE FAVORABLE SHEAR IS EXPECTED TO SET UP AND MOISTURE IS MORE FAVORABLE WITH SOUTHERLY WINDS. THE MAIN THREAT WITH STRONG TO SEVERE STORMS WILL BE DIME TO QUARTER- SIZE HAIL. SEVERE OUTLOOK HOWEVER IS VERY CONDITIONAL AND OVERALL NOT VERY IMPRESSIVE. MADE A QUICK UPDATE TO REMOVE POPS THIS MORNING AND ADJUST CLOUDS SLIGHTLY. EVERYTHING ELSE IS ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT THU MAY 30 2013 WILL GO AHEAD AND CANCEL THE FLASH FLOOD WATCH FOR OUR SOUTHEASTERN ZONES. REMNANTS OF LIGHT TO SPOTTY MODERATE RAINFALL ARE MOVING NORTHWARD AT THIS TIME EAST OF I 29...BUT IT IS NOT ENOUGH TO EXAGGERATE ANY EXISTING FLOODING PROBLEMS. IT IS LIKELY THAT THE HEAVIEST RAINFALL FOR TODAY WILL ALSO STAY TO THE SOUTH OF THE SIOUX FALLS FORECAST AREA. SYNOPTIC SITUATION SHOWS A HUGE UPPER LOW IN TWO PIECES...GENERALLY EXTENDING FROM OFF THE BRITISH COLUMBIA COAST TO THE NORTHWESTERN PLAINS. LARGE AREA OF SURFACE LOW PRESSURE FOLLOWS SUIT AND IS SITUATED OVER CENTRAL SD...WITH TROUGHING NUDGING DOWN INTO THE CENTRAL PLAINS. ANOTHER SURFACE LOW IS SITUATED OVER THE OKLAHOMA PANHANDLE...WHICH IS THE RESULT OF A VERY STRONG SHORTWAVE MOVING EASTWARD FROM THAT AREA TODAY...INTO KANSAS...MISSOURI...SOUTHERN IOWA AREAS. THERE IS A LOT OF MODEL CONSENSUS THAT THE HEAVIER RAIN WILL BE CONFINED TO THAT SHORT WAVE AND SOUTH OF OUR AREA. SO FROM HERE AND OUT...WE ARE MAINLY LEFTOVER WITH ISOLATED TO SCATTERED INSTABILITY SHOWERS AND A FEW POSSIBLE THUNDERSTORMS... ESPECIALLY THIS AFTERNOON. WENT DRY FOR OUR WESTERN ZONES THIS MORNING AS THERE IS SIMPLY NO SIGN OF CONVECTIVE REDEVELOPMENT YET IN CENTRAL NEB. THE 850MB STREAMLINES PRETTY MUCH TELL THE STORY FOR NOW...IN THAT THEY ARE WRAPPING FROM A WESTERLY DIRECTION UNDERNEATH THE AFOREMENTIONED LOW...COMING OUT OF WESTERN AND CENTRAL NEBRASKA AND INTO OUR WESTERN ZONES. SO THE MOIST LOW LEVEL FLOW IS CUTOFF IN OUR WEST. ALONG AND EAST OF I 29...THE LOW LEVEL JET STILL EXISTS BUT IS WEAKER THEN YESTERDAY. ML CAPE IS PRETTY ANEMIC THIS MORNING...BUT DOES INCREASE THIS AFTERNOON AS ANY CLEARING WILL HELP TO HEAT THINGS OUT. IN ADDITION...SOME OF THE HIGHER RESOLUTION MODELS ARE STRONGLY HINTING AT THE SURFACE TROUGH MOVING EASTWARD INTO THE JAMES RIVER VALLEY THIS AFTERNOON...WITH A DRY LINE PRESSING THROUGH OUR SOUTH CENTRAL SD ZONES. THE TROUGH MAY PROVIDE A FOCUS FOR SCATTERED SHOWERS AND STORMS ALONG AN AXIS FROM YANKTON TO SIOUX FALLS AND VICINITIES... HELPED BY STRONGLY VEERING PROFILES JUST AHEAD OF THE DRY LINE. ELSEWHERE AS THE AFTERNOON PROGRESSES...POPCORN TYPE INSTABILITY SHOWERS AND THUNDERSTORMS SHOULD DOMINATE THIS AREA OF THE SCATTERED VARIETY. SO VERY MUCH A NUISANCE SITUATION. HIGHS TODAY STILL LOOK LIKE WIDESPREAD 70S...WHICH SHOULD BE ENOUGH TO PROVIDE SOME AFTERNOON INSTABILITY. FOR TONIGHT...ONCE THE HEATING SUBSIDES...SO WILL OUR CHANCE FOR INSTABILITY RAINFALL. BUT LATE TONIGHT...THE UPPER LOW BEGINS TO WRAP IN A CHANCE FOR SHOWERS INTO OUR NORTHWEST AREAS. MOISTURE PROFILES IN THAT AREA ARE QUITE HIGH BY LATE TONIGHT...WITH DRY SLOTTING TAKING OVER AFTER MIDNIGHT FOR THE REST OF OUR FORECAST AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 359 AM CDT THU MAY 30 2013 ON FRIDAY AND SATURDAY...OUR WEATHER WILL CONTINUE TO BE DOMINATED BY THE UPPER LOW. IT WILL STILL BE CLOSED ON FRIDAY AS IT MOVES SLOWLY EASTWARD. THEN IT WILL BECOME A TROUGH ON SATURDAY AS IT MOVES INTO THE NORTHERN MISSISSIPPI VALLEY. PV IS VERY STRONG ON THE NORTH AND WEST SIDES OF THE UPPER LOW...ALONG WITH STRONG TROWALING CLEARLY EVIDENT AT THE MID LEVELS. ALL OF THIS IS CAUSING A HIGH MOISTURE PROFILE WHICH MOVES SOUTHEASTWARD...SO EXPECT LIGHT SHOWERS LIKELY TO MOVE IN THAT DIRECTION THROUGH TIME AND EVENTUALLY ENCOMPASSING ALMOST THE ENTIRE WESTERN HALF OF OUR FORECAST AREA. MODELS ARE CERTAINLY SHOWING QUITE A CONVEYOR BELT OF PRECIPITATION...MOVING NORTHEASTWARD AHEAD OF THE LOW FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES...THEN LIGHT RAIN ARCHING BACK THROUGH PARTS OF THE NORTHERN AND WESTERN PLAINS ALONG THE TROWALING. ANOTHER THING TO WATCH FOR FRIDAY AFTERNOON...IS THAT THE LEADING EDGE OF THE COLD FRONT COULD SPARK SOME SCATTERED THUNDERSTORMS ALONG AND SOUTH OF A SIOUX CITY TO WINDOM MN LINE. DO NOT THINK THE COVERAGE OF STORMS WILL BE ALL THAT GREAT...AND ALMOST WENT ISOLATED. BUT AGAIN SOMETHING TO WATCH FOR. THIS COLD FRONT MOVES EASTWARD AND WILL GIVE OUR FORECAST AREA SOME VERY CHILLY AIR TO CONTEND WITH ON SATURDAY. SATURDAY DOES NOT LOOK LIKE A PLEASANT DAY...AS EVEN IF LIGHT SHOWERS DO NOT OCCUR AT YOUR LOCATION...IT WILL BE CONSIDERABLY CLOUDY AND WINDY ALONG WITH THE VERY CHILLY TEMPERATURES. RECORD LOW HIGHS ON JUNE 1 ARE QUITE A BIT COLDER THAN WHAT WE HAVE FORECAST HOWEVER...SO THEY SHOULD NOT BE IN JEOPARDY OF FALLING. SOME OF THE LIGHT SHOWERS BY SATURDAY AFTERNOON WILL BE THE RESULT OF WHAT HEATING THERE IS. THEREFORE BY SATURDAY NIGHT...ELIMINATED ALL POPS IN OUR EASTERN ZONES. CONCERNING TEMPERATURES...COOLED OFF OUR WESTERN ZONES A FAIR AMOUNT ON FRIDAY BEHIND THE COLD FRONT...NOTING THE CLOUDY AND SHOWERY CONDITIONS. THE SUNDAY THROUGH WEDNESDAY PERIOD WILL START DRY AND COOL SUNDAY...BUT THE COOL WILL FEEL NICE WITH LIGHT TO MODERATE NORTHERLY WINDS BEGINNING TO TURN EASTERLY AS SURFACE RIDGE PASSES BY TO THE NORTH. WAS LOOKING FOR MONDAY TO BE DRY AND A LITTLE WARMER...BUT IT LOOKS LIKE SOUTHEASTERLY THERMAL LIFT PATTERN WILL DEVELOP SOON ENOUGH TO MENTION A SMALL CHANCE OF STORMS. THIS CHANCE SHOULD BE SOMEWHAT BIGGER FOR THE REST OF THE PERIOD...MONDAY NIGHT INTO WEDNESDAY...AS UPPER WAVE DIGS FROM SOUTHWEST CANADA INTO THE DAKOTAS. WILL GO WITH GUIDANCE KEEPING TEMPERATURES FAIRLY CLOSE TO SEASONAL FOR NOW...THIS SEEMS IN LINE WITH THE NEW ECMWF. THE GFS WOULD SUGGEST COOLER BY WEDNESDAY. SINCE NO TREND IS SEEN AS TO WHICH MODEL IS BETTER THAT FAR AHEAD...GUIDANCE AND CONSISTENCY WIN FOR NOW. FOR THE MOMENT DO NOT EXPECT MOISTURE INFLOW TO BE ENOUGH FOR SEVERE STORMS OR HEAVY RAIN...BUT MID AND UPPER FLOW WILL BE MORE THAN AMPLE SO WILL HAVE TO BE OPEN TO POSSIBLE CHANGE OF THINKING IN COMING DAYS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 638 AM CDT THU MAY 30 2013 WIDESPREAD TO AREAS OF CEILINGS 1-3K FEET MOSTLY FROM A BKX/FSD/SUX LINE AND EAST SHOULD IMPROVE FROM THE WEST 15Z-18Z. OTHERWISE VFR WILL BE THE RULE OVER THE AREA WITH BRIEF CEILIGNS 2-3K FEET AND VISIBILITIES 3-5SM IN SGACTTERED TO ISOLATED SHOWERS. ISOLATED THUNDERSTORMS POSSIBLE 18Z-31/02Z. WIDESPREAD CEILINGS 2-3K FEET MAY DEVELOP WESTERN EDGE OF FORECAST AREA AFTER 31/06Z. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE... SHORT TERM...MJF LONG TERM...MJF/WILLIAMS AVIATION...
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
340 PM CDT THU MAY 30 2013 .TONIGHT AND FRIDAY... A CONDITIONAL CHANCE OF THUNDERSTORMS THIS AFTERNOON AND EVENING... BASED ON WHERE THE CAP WILL HOLD. WHILE THE CAP WILL LIKELY HOLD...IF IT DOES BREAK...WITH RAP SB CAPES OF 4000 J/KG...STORMS COULD RAPIDLY BECOME SEVERE. 0-6 KM SHEARS WERE 40 KTS IN THE BIG COUNTRY WITH HIGHER VALUES FARTHER NORTH. A TORNADO WATCH IS IN EFFECT FOR NORTHERN SECTIONS OF THE THE BIG COUNTRY THROUGH 10 PM CDT...WHERE AN ENHANCED CUMULUS FIELD WAS INDICATED. DRYLINE OTHERWISE EXTENDED ALONG THE WESTERN EDGE OF THE SAN ANGELO CWA THIS AFTERNOON...FROM IRAAN TO SWEETWATER TO NEAR ASPERMONT. BEST CHANCE OF A STORM WILL BE IN LOW LEVEL CONVERGENCE ALONG THE FRONT...AND MAINLY NORTH OF THE I-20 CORRIDOR. GENERAL MOVEMENT OF STORMS WILL BE EAST ...WITH SEVERE OR STORM STORMS PROPAGATING SOUTHEAST. OTHERWISE ANTHER WARM NIGHT WITH CONTINUED MOISTURE TRANSPORT FROM THE GULF. OVERNIGHT LOWS WILL BE IN THE LOWER 70S. A DRYLINE WILL BE MOVING A LITTLE FARTHER EAST FRIDAY AFTERNOON....ALONG A SONORA...SAN ANGELO... ABILENE...HASKELL LINE. WITH GFS 850 MB TEMPERATURES INCREASING TO 30 C WEST OF THE DRYLINE...SHOULD SEE SURFACE TEMPERATURES AT OR SLIGHTLY ABOVE 100 DEGREES F WEST OF THE DRYLINE... WITH 90S TO THE EAST. FIRE WEATHER CONDITIONS WILL BE ELEVATED WEST THE DRYLINE THIS AFTERNOON. WINDS HOWEVER WILL WEAKEN SLIGHTLY THIS EVENING...THEN BECOME MORE GUSTY BY MIDNIGHT...AS 45-50 KT 850 MB LLJ DEVELOPS. GUSTY MORNING SOUTH TO SOUTHWEST WINDS WEAKEN ENOUGH BY FRIDAY AFTERNOON TO KEEP CONDITIONS FROM BECOMING CRITICAL FOR FIRE WEATHER. .SATURDAY THROUGH SUNDAY... NEXT BEST CHANCE OF RAIN FOR WEST CENTRAL TEXAS WILL COME FOR THE WEEKEND...AS A COLD FRONT MOVES INTO THE AREA. MODELS HAVE BEEN FAIRLY CONSISTENT WITH THE TIMING OF THE FRONT...MOVING TO NEAR THE NORTHWEST BORDER OF THE AREA BY SATURDAY MORNING...AND THEN SLOWLY SLIDING IT DEEPER INTO WEST CENTRAL TEXAS DURING THE DAY. AT LEAST SCATTERED SHOWERS AND STORMS SHOULD BREAK OUT ALONG AND NORTH OF THE BOUNDARY SATURDAY AFTERNOON...AND CONTINUE THROUGH THE OVERNIGHT HOURS. HAVE INCREASED RAIN CHANCES ACROSS MUCH OF THE AREA JUST A LITTLE. WHATS LEFT OF THE BOUNDARY SHOULD BE DISSIPATING ACROSS THE AREA DURING THE DAY ON SUNDAY. WITH NOT MUCH OF THE BOUNDARY LEFT...DONT EXPECT STORMS TO BE QUITE AS WIDESPREAD. WILL CONTINUE THE SLIGHT CHANCE POPS OVER MUCH OF THE AREA. .SUNDAY THROUGH THURSDAY... DRY CONDITIONS FOR THE PERIOD FOR NOW. MID AND UPPER LEVEL RIDGE BUILDS INTO THE SOUTHERN ROCKIES...PLACING WEST CENTRAL TEXAS IN WEAK NORTHWEST FLOW ALOFT. APPEARS WE MAY BE A LITTLE TOO CLOSE TO THE RIDGE CENTER TO TAKE ADVANTAGE OF THE NORMALLY WETTER SUMMER NORTHWEST GLOW PATTERN INTO WEDNESDAY. MODELS HAVE SOME DIFFERENCES BY THE TIME WE GET INTO THURSDAY...WITH THE GFS SUPPRESSING THE RIDGE ENOUGH TO ALLOW ANOTHER FRONT INTO THE AREA...WHILE THE ECMWF TRIES TO CLOSE OFF AN UPPER LOW OVER SOUTHERN CALIFORNIA. AT THIS POINT...WILL JUST LEAVE DRY FOR NOW. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 72 99 74 92 65 / 10 10 10 20 30 SAN ANGELO 73 99 74 96 67 / 10 10 5 20 30 JUNCTION 72 94 73 94 71 / 10 5 5 10 30 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 04/07/07
AREA FORECAST DISCUSSION...CORRECTED
NWS MILWAUKEE/SULLIVAN WI
446 PM CDT THU MAY 30 2013 .SHORT TERM... .TONIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM. ONGOING SCATTERED CONVECTION WITH MORE DISCRETE-TYPE CELLS ASSOCIATED WITH A VORT MAX ROTATING AROUND A NEGATIVELY TILTED 500MB UPPER LOW OVER THE NORTHERN PLAINS...AND ON THE NOSE OF THE 850MB LOW LEVEL JET. MOST OF THE SEVERE THUNDERSTORM WARNINGS HAVE BEEN LARGE HAIL AND THE TOKEN DAMAGING WINDS. DECENT LOW LEVEL SHEAR AND CAPE STILL WARRANTS TORNADO WATCH. WEAK TORNADOES ARE POSSIBLE. THE STORMS MAY CONGEAL INTO BOWING LINE SEGMENTS LATER THIS AFTERNOON AS THEY GET INTO SOUTHEAST WI PER THE 17Z HRRR MODEL RUN. MEANWHILE... A STRONGER VORT MAX CURRENTLY OVER MISSOURI WILL ROLL ACROSS IOWA AROUND 00Z. STORMS AHEAD OF THIS DISTURBANCE WILL MOST LIKELY BE IN A LINE/MCS MODE AS IT REACHES NORTHERN IL/SOUTHERN WI. EXPECTING THIS TO MOVE ACROSS ALL OF THE MKX AREA THIS EVENING. LATEST 17Z HRRR SPED THIS UP WITH THE LEADING EDGE CLEARING EASTERN WI BY 03Z...WHILE THE 12Z NAM DELAYS IT OVER THE MKX AREA FROM 03-09Z. EXPECT A BREAK IN PRECIP LATE TONIGHT INTO FRIDAY MORNING AFTER THIS SECONDARY ROUND. THEN WE WILL BE IN ANOTHER FAVORABLE SYNOPTIC SETUP FOR MORE SEVERE STORMS ON FRIDAY. THE 500MB UPPER LOW WILL SHIFT A LITTLE CLOSER INTO THE EASTERN DAKOTAS AND ANOTHER VORT MAX WILL SWING INTO SOUTHERN WI AS THE LEFT EXIT REGION OF A 100KT UPPER JET MOVES THROUGH. CONVECTIVE MODE WILL LIKELY BE A LINE OF STORMS WITH A SUBTLE COLD-FRONT. DAMAGING WINDS THE MAIN SEVERE THREAT. ONE UNCERTAINTY WITH FRIDAY THUNDERSTORMS WILL BE THAT THE LINE COULD FORM IN ILLINOIS AND MOVE EAST AND JUST CLIP SOUTHEAST WI OR EVEN MISS IT ALL TOGETHER. FRIDAY NIGHT AND THROUGH SATURDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH THE MID/UPPER TROUGH WILL PUSH INTO THE UPPER MISSISSIPPI VALLEY REGION. THE 250 MB JET MAX INCREASES TO 100 KNOTS ACROSS SOUTHERN AND NORTHEAST WISCONSIN WITH MODERATE UPPER DIVERGENCE OVER SOUTHEAST WISCONSIN DURING THE EVENING. SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY EVENING WITH A MID DRY PUNCH OVER MUCH OF THE AREA. THOUGH THE BEST LOW LEVEL WIND MAX WILL BE TO THE SOUTH AND EAST...STRONGER STORMS ARE NOT OUT OF THE QUESTION ESPECIALLY WITH WIND SHEAR A BIT HIGHER THAN PREVIOUS DAYS. THE CWASP SEVERE PARAMETER IS HIGHEST ACROSS NORTHEAST ILLINOIS LOWER VALUES EXTENDS CLOSER TO THE UPPER LOW OVER PORTIONS OF SOUTH CENTRAL WISCONSIN. WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH SOUTHERN WISCONSIN BY SATURDAY NIGHT. NAM FORECAST SOUNDINGS STILL HAVE 1300 J/KM OF CAPE SATURDAY AFTERNOON IF FORECAST DEW POINTS ARE NOT TOO HIGH. .LONG TERM... SUNDAY THROUGH THURSDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH MAIN UPPER LEVEL TROUGH AXIS WILL MOVE ACROSS THE WESTERN GREAT LAKES SATURDAY NIGHT THEN INTO SOUTHERN CANADA ON SUNDAY. FORECAST SOUNDINGS SHOW MOISTURE TRAPPED BELOW AN INVERSION AROUND 7 THSD FT...SO EXPECT CUMULUS/STRATOCUMULUS SUNDAY. COOLER AIR IS EXPECTED TO ARRIVE WITH THE SHORTWAVE. THE GFS AND ECMWF ARE FAIRLY SIMILAR IN BRINGING ANOTHER UPPER TROUGH ACROSS THE NORTHERN PLAINS MONDAY NIGHT AND REACHING THE UPPER MISSISSIPPI VALLEY WEDNESDAY. ON THURSDAY THE GFS BRINGS THE UPPER TROUGH ACROSS WISCONSIN WITH A BROADER MORE NORTH LOCATION ON THE 00Z ECMWF. STILL SOME POTENTIAL OF INSTABILITY SHOWERS SUNDAY BEFORE HIGH PRESSURE DOMINATES WISCONSIN MONDAY. BY TUESDAY SHOWERS/THUNDERSTORMS APPROACH THE MISSISSIPPI RIVER AREA TUESDAY EVENING WITH A CHANCE OF SHOWERS/THUNDERSTORMS WEDNESDAY AND THURSDAY. && EXPECT GUSTS BETWEEN 25 AND 30 KTS TO PERSIST UNTIL EVENING AS MIXING CEASES. DISCRETE THUNDERSTORMS WITH SOME PRODUCING LARGE HAIL MAINLY IN SOUTH CENTRAL WI. EXPECTING STORMS TO CONGEAL AT SOME POINT AND STRAIGHT-LINE WINDS WILL BECOME THE MAIN THREAT FOR ALL OF SOUTH CENTRAL AND SOUTHEAST WI. STORMS ARE DEVELOPING RAPIDLY...SO WATCH THE RADAR CLOSELY FOR NEW DEVELOPMENTS. WEAK TORNADOES ARE POSSIBLE WITH DECENT LOW-LEVEL ROTATION. ANOTHER ROUND...A LINE OF THUNDERSTORMS...IS EXPECTED EARLY THIS EVENING AND THESE WILL LIKELY SPREAD ALL THE WAY ACROSS SOUTHERN WI. STRAIGHT-LINE WINDS WILL BE THE MAIN SEVERE WEATHER THREAT. AFTER A BREAK LATE TONIGHT/EARLY FRIDAY...EXPECT A LINE OF THUNDERSTORMS TO DEVELOP ALONG A WEAK COLD FRONT SOMEWHERE IN IA/IL AND TRACK ENE MIDDAY FRIDAY. THESE MAY SWEEP ACROSS ALL OF SOUTHERN WI OR JUST CLIP SOUTHEAST WI. STAY TUNED TO THE FORECAST FOR THIS ONE. && .MARINE... GUSTY SOUTH WINDS DUE TO MIXING OVER THE LAND WILL AFFECT SHORELINE NEARSHORE AREAS UNTIL THIS EVENING. WINDS WILL BE LESS GUSTY TOWARD THE OPEN WATERS. HOWEVER...THE TIGHT PRESSURE GRADIENT OVER THE LAKE WILL ALLOW SUSTAINED WINDS TO BE IN THE 15 TO 20 KNOT RANGE TODAY AND TONIGHT. STABLE AIR DOWN AT LAKE LEVEL WILL KEEP WAVES FROM RESPONDING TOO MUCH TO THE GUSTY WINDS. THUNDERSTORMS EXPECTED THIS EVENING AND AGAIN FRIDAY MIDDAY AND AGAIN SOMETIME ON SATURDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ TONIGHT/FRIDAY AND AVIATION/MARINE...MRC FRIDAY NIGHT THROUGH THURSDAY...HENTZ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
159 PM CDT THU MAY 30 2013 .UPDATE... 18Z DVN SOUNDING CAME IN WITH SBCAE AROUND 2000 J/KG AND INCREASE IN FLOW IN THE LOWEST 6 KM. 50-60 KNOT WINDS WERE NOTED IN THE 800-500 MB LAYER. FLOW WAS MAINLY UNIDIRECTIONAL AND THE PRIMARY WEAKNESS FOR TORNADIC SUPERCELLS WAS THE WEAK FLOW UP AROUND ANVIL LEVEL...WHICH WOULD FAVOR HP TYPE STORMS WITH MORE WIND THREAT. HOWEVER...0-3KM SHEAR OF 30-40 KNOTS WOULD SUPPORT THREAT FOR MESOVORTEX/QLCS TORNADO THREAT GIVEN LCL OF 1000M OR LESS AND 0-1KM SHEAR OF 20-25 KNOTS. RUC13 1 HOUR FORECAST FOR 19Z HAS SIG TORNADO PARAMETER OF 3-4 ACROSS NORTHERN ILLINOIS WITH VALUES OF 1-2 ACROSS SOUTHERN WISCONSIN. THUS CONTINUED THREAT FOR WIND DAMAGE...TORNADOES...AND SEVERE HAIL FOR NEXT FEW HOURS. HIGH LEVEL FLOW SHOULD INCREASE ON NOSE OF DIFFLUENT UPPER JET BY THIS EVENING AND WOULD SUPPORT INCREASING THREAT FOR TORNADIC SUPERCELLS IF THE ACTIVITY CAN REMAIN DISCRETE. && .PREV DISCUSSION... /ISSUED 1259 PM CDT THU MAY 30 2013/ UPDATE... TORNADO WATCH IN EFFECT FOR SOUTH CENTRAL WI...INCLUDING MARQUETTE/GREEN LAKE COUNTIES THROUGH DANE AND ROCK COUNTIES AND WEST TO SAUK AND LAFAYETTE COUNTIES. SCATTERED CONVECTION IS DEVELOPING IN SOUTH CENTRAL WI AS THE 850MB LOW LEVEL JET POINTS INTO THE REGION. DEEP SHEAR IS STILL WEAK...BUT LOW LEVEL SHEAR IS HIGH IN THE 20 TO 30 KNOT RANGE. 0-3KM CAPE IS DECENT WITH VALUES OVER 100 J/KG. ENVIRONMENT IS CONDUCIVE FOR RAPID INTENSIFICATION OF ISOLATED STORMS. THE LOW LCL AND HIGH 0-3 AND 0-1 HELICITY VALUES SUPPORT TORNADO POTENTIAL. LARGE HAIL IS LIKELY IN THESE ISOLATED CELLS AS WELL. CIMSS CLOUD TOP COOLING HIGHLIGHTED AN AREA OF RAPID COOLING IN WESTERN SAUK COUNTY AT 1225 PM AND A SEVERE THUNDERSTORM WARNING WAS ISSUED ON IT FOR 1-INCH HAIL A FEW MINUTES AGO. THE 16Z HRRR SHOWS SCATTERED CONVECTION OVER SOUTH CENTRAL WI EVOLVING INTO A LINE OVER SOUTHEAST WI AROUND 21Z. THE STRONG VORT MAX SWINGING UP HERE LATER SHOWS ANOTHER CELL/LINE EVOLUTION MOVING THROUGH NORTHERN IL AND SOUTHERN WI THIS EVENING. PREV DISCUSSION... /ISSUED 1043 AM CDT THU MAY 30 2013/ UPDATE... WE ARE RAMPING UP THE SEVERE THREAT FOR SOUTH CENTRAL WI FOR THIS AFTERNOON. THERE IS A HIGH PROBABILITY OF STRONG THUNDERSTORMS IN THE UPPER MIDWEST...AND A GOOD CHANCE OF SEVERE WINDS IN SOUTH CENTRAL WI. SOUTHERN WISCONSIN IS BACK IN THE SLIGHT RISK FOR SEVERE WEATHER AREA TODAY/TONIGHT. A STRONG SHORTWAVE CURRENTLY OVER OKLAHOMA WILL BE SWINGING UP INTO IOWA AROUND 21Z THIS AFTERNOON. THERE IS A WEAKER SHORTWAVE OUT AHEAD OF THAT WHICH WILL GET INTO EASTERN IOWA/SOUTHERN WI JUST AFTER 18Z. THE LEADING SHORTWAVE WILL NEED TO BE WATCHED FOR EARLY AFTERNOON CONVECTION OVER SOUTH CENTRAL WI. THE MAIN STRONG SHORTWAVE WILL LIKELY DRIVE A THUNDERSTORM COMPLEX ACROSS ALL OF SOUTHERN WISCONSIN LATE AFTERNOON EARLY EVENING. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY SHOWS A TONGUE OF HIGH PROBABILITY OF UPDRAFT HELICITY VALUES GREATER THAN 25 M2/S2 STRETCHING INTO CENTRAL WISCONSIN. THE HIGHEST VALUES ARE FOCUSED OVER THE PLAINS AND EASTERN IOWA...BUT THE 60-70 PERCENTS OVER SOUTH CENTRAL WI ARE STILL VERY IMPRESSIVE. THE CRAVEN-WIEDENFELD AGGREGATE SEVERE PARAMETER WHICH COMPILES INGREDIENTS FOR SEVERE THUNDERSTORMS AND GIVES A SCORE/PERCENTAGE CONTINUES TO HAVE VERY HIGH VALUES IN SOUTHWEST AND SOUTH CENTRAL WI IN THE 75-82 PERCENT RANGE...WITH RUC13 VALUES EVEN HIGHER. IN ADDITION...CIPS ANALOGS SHOW A HISTORY OF SEVERE WEATHER OCCURRING WITH THE CURRENT SYNOPTIC PATTERN. MODE OF CONVECTION IS STILL IN QUESTION. THE MOST LIKELY MODE IS LINES OF STORMS PRODUCING BOWING SEGMENTS. THE SHEAR IS RELATIVELY WEAK OVER THE REGION AND UNIDIRECTIONAL. IT IS FORECAST TO STRENGTHEN THROUGH THE AFTERNOON...AS WILL LOW LEVEL WIND SHEAR...WHICH WOULD HELP CELLS REMAIN MORE DISCRETE OR HAVE JUST SMALL BOWING LINE SEGMENTS. TORNADO DEVELOPMENT WILL BE POSSIBLE GIVEN LOW LCL AND HIGH LOW LEVEL SHEAR. THE WIDESPREAD CUMULUS CLOUDS THAT DEVELOPED THIS MORNING WILL ACTUALLY HELP THE SEVERE SITUATION BY KEEPING US FROM MIXING OUT TOO MUCH AND ALLOWING THE DEWPOINTS TO REMAIN HIGH. THE 13Z HRRR IS SHOWING A MORE DISCRETE MODE OVER SOUTHERN WI EARLY THIS AFTERNOON...WITH A SQUALL LINE/MCS DEVELOPING WITH THE BIGGER VORT MAX LATE THIS AFTERNOON/EVENING. THE QUAD CITIES NWS OFFICE WILL BE DOING AN 18Z UPPER AIR SOUNDING TO ALLOW US TO BETTER ASSESS THE SEVERE POTENTIAL. AVIATION/18Z TAFS/... EXPECT GUSTS BETWEEN 25 AND 30 KTS TO LAST THROUGH MOST OF THE DAY. MVFR BROKEN CUMULUS CLOUDS DEVELOPED AND WILL GRADUALLY LIFT TO VFR BY 18Z. STORMS WILL DEVELOP OVER EASTERN IOWA AND MOVE NORTHEAST INTO SOUTHERN WISCONSIN EARLY THIS AFTERNOON. MADISON WILL HAVE THE BEST CHANCE FOR EARLIER THUNDERSTORMS. SOME MAY BE SEVERE. THEN ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED LATE AFTERNOON/EARLY EVENING AND THESE WILL LIKELY SPREAD ALL THE WAY INTO SOUTHEAST WI. STRAIGHT-LINE WINDS ARE THE MAIN SEVERE WEATHER THREAT. MARINE... GUSTY SOUTH WINDS DUE TO MIXING OVER THE LAND WILL AFFECT SHORELINE NEARSHORE AREAS ALL DAY TODAY. MAY NEED A SMALL CRAFT ADVISORY TO HANDLE THIS. WINDS WILL BE LESS GUSTY TOWARD THE OPEN WATERS. HOWEVER...THE TIGHT PRESSURE GRADIENT OVER THE LAKE WILL ALLOW SUSTAINED WINDS TO BE IN THE 15 TO 20 KNOT RANGE TODAY. STABLE AIR DOWN AT LAKE LEVEL WILL KEEP WAVES FROM RESPONDING TOO MUCH TO THE GUSTY WINDS. PREV DISCUSSION... /ISSUED 449 AM CDT THU MAY 30 2013/ TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM CONVECTION HAS LIFTED NORTH OF THE FORECAST AREA WITH SHORT WAVE/MCV AND ADDITIONAL SUPPORT FROM RIGHT ENTRANCE REGION OF UPPER JET. MODELS DAMPEN FIRST SHORT WAVE CURRENTLY DRIVING SRN PLAINS CONVECTION AND FOCUS ON WAVE NEAR THE PANHANDLE REGION THAT WILL SWING UP TOWARDS IA/NEB BY 00Z FRI AS 500 MB LOW GOES NEGATIVE-TILT. WITH COMBINATION OF CENTRAL PLAINS SHORT WAVE/MCV AND 850 MB JET MAX AND INSTABILITY ON AREA SOUNDINGS...THOUGH CAPE VALUES MAY BE A BIT TOO HIGH DUE TO GENEROUS SURFACE DEW POINTS...WILL FOLLOW CONSENSUS BLEND POPS AND INCREASE PRECIPITATION CHANCES RAPIDLY THROUGH THE MORNING. HIGH POPS CONTINUE INTO THE EVENING...THEN TAPER OFF AS FORCING WITH WAVE AND LOW-LEVEL JET MAX LIFT OFF TOP THE NORTHEAST. WILL HAVE TO WATCH WESTERN COUNTIES OF S CENTRAL WI FOR FLASH FLOODING POTENTIAL AFTER RECEIVING HEAVY RAIN WITH THE CONVECTION WEDNESDAY EVENING. LATEST SPC DAY 1 OUTLOOK HAS SHIFTED SLIGHT RISK TO THE SOUTHWEST OUT OF OF WISCONSIN AS FAVORABLE SHEAR FOR ROTATING CELLS LESSENS THROUGH THE DAY...BUT AN ISOLATED WIND/HAIL MAKER NOT OUT OF THE QUESTION. FRIDAY AND SATURDAY...FORECAST CONFIDENCE...MEDIUM SOUTHERN WISCONSIN WILL REMAIN IN THE WARM SECTOR FRIDAY AS LOW PRESSURE OVER NORTH DAKOTA AND MINNESOTA REMAINS NEARLY STATIONARY. SHOWERS AND STORMS ARE THUS LIKELY ONCE AGAIN. THOUGH THE BEST LOW LEVEL FLOW WILL BE TO THE SOUTH AND EAST...STRONGER STORMS ARE NOT OUT OF THE QUESTION WITH SIMILAR UP TO 1000 J/KG OF SURFACE BASED CAPE...AND WIND SHEAR ACTUALLY A BIT HIGHER THAN PREVIOUS DAYS. LOOKS LIKE BEST CHANCE FOR SHOWERS AND STORMS WILL BE LATE AFTERNOON INTO THE NIGHT...AS ANOTHER SHORTWAVE ROTATES THROUGH THE AREA. TEMPERATURES WILL BE SIMILAR FRIDAY AS THURSDAY...PUSHING OR REACHING 80 MOST PLACES. PROBABLY A BIT TRICKY NEAR THE LAKE AGAIN UNDER SOUTHERLY WINDS...BUT MOST AREAS SHOULD SEE THE WARMER TEMPS. WEAKENING LOW PRESSURE WILL FINALLY DRAG A COLD FRONT THROUGH SOUTHERN WISCONSIN BY SATURDAY NIGHT. MODELS HAVE SLOWED A BIT WITH THE FRONT...SO TEMPS AND POPS HAVE TRENDED IT BIT HIGHER WITH SOUTHERN WISCONSIN REMAINING IN THE WARM SECTOR A BIT LONGER. SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM MAIN UPPER LEVEL TROUGH AXIS WILL MOVE THROUGH SUNDAY...POSSIBLY BRINGING A FEW SHOWERS. COOLER AIR IS EXPECTED TO ARRIVE WITH THE SHORTWAVE...WITH TEMPERATURES FALLING BACK BELOW NORMAL. SHOULD BE PLEASANT MONDAY UNDER HIGH PRESSURE...WITH A CHANCE FOR SHOWERS AND STORMS RETURNING LATER TUESDAY INTO WEDNESDAY. HIGHS WILL LIKELY REMAIN A FEW DEGREES BELOW NORMAL THROUGH THE FIRST HALF OF NEXT WEEK. AVIATION/12Z TAFS/... WILL KEEP WIND SHEAR IN ALL OF THE TAFS...WITH WIND PROFILERS PICKING UP 35 TO 40 KT WINDS BETWEEN 1500-2000 FT...UNTIL SURFACE WINDS INCREASE WITH MIXING AFTER DAYBREAK. EXPECT SOUTHERLY GUSTS BETWEEN 25 AND 30 KTS BY MID-MORNING AND LASTING THROUGH MOST OF THE DAY. INCREASED LOW-LEVEL MOISTURE AND COOLING EFFECTS OF LAST NIGHT/S STORMS HAVE PRODUCED FOG AT KMSN WHICH SHOULD LIFT WITH INCREASING WINDS AFTER SUNRISE. OTHERWISE VFR CONDITIONS THROUGH MOST OF THE DAY. WHILE EXACT TIMING IS QUESTIONABLE...WEAK UPPER DISTURBANCE AND ANOTHER LOW-LEVEL JET MAX APPROACHING THE UPPER MIDWEST WILL BRING INCREASING CHANCES FOR THUNDERSTORMS. BEST CHANCES STAY WEST OF KMSN UNTIL MID-LATE MORNING...THEN SPREAD EAST AND INCREASE THROUGH THE AFTERNOON. SHOWERS AND STORMS MOST LIKELY FROM LATE AFTERNOON THROUGH THE EVENING BRINGING MVFR CIGS/VSBYS...POSSIBLY DROPPING TO IFR WITH HEAVY DOWNPOURS OF RAIN. WILL THEN KEEP MVFR CONDITIONS THROUGH THE REMAINDER OF THE FORECAST. MARINE... SOUTH WINDS WILL INCREASE RAPIDLY AFTER SUNRISE...WITH GUSTS TO 20 KNOTS BY MID TO LATE MORNING. PREVAILING WINDS HOLD JUST BELOW SMALL CRAFT CRITERIA...THOUGH THERE WILL BE A FEW GUSTS TO 25 KNOTS. HAVE ADDED A CAUTIONARY STATEMENT FOR SMALL CRAFT IN THE NEARSHORE FORECAST AND IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. EXPECT THUNDERSTORM CHANCES TO INCREASE THROUGH THE LATE MORNING AND AFTERNOON...BECOMING MOST LIKELY THIS EVENING. WHILE THE STORMS ARE EXPECTED TO STAY BELOW SEVERE LEVELS...GUSTY WINDS...SMALL HAIL AND VISIBILITY-REDUCING HEAVY RAINS ARE POSSIBLE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...CRAVEN TODAY/TONIGHT AND AVIATION/MARINE...MRC FRIDAY THROUGH WEDNESDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1225 PM CDT THU MAY 30 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 333 AM CDT THU MAY 30 2013 CURRENTLY AS OF 0830Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED UPPER TROUGHING FROM THE NORTHEAST PACIFIC INTO THE NORTHERN ROCKIES WITH AN UPPER LOW IN NORTHEAST WYOMING...WHILE DOWNSTREAM RIDGING WAS PRESENT ACROSS THE EASTERN U.S.. ALSO TO NOTE ON WATER VAPOR IS A FAIRLY POTENT SHORTWAVE OVER THE TEXAS AND OKLAHOMA PANHANDLES IN THE BASE OF THIS TROUGHING. NEARLY UNIDIRECTIONAL SOUTH TO SOUTHWEST FLOW EXISTED BETWEEN THE TROUGHING AND RIDGING... WITH SOME VERY STRONG WINDS AT 850MB. VWP AND PROFILER DATA SHOWED SPEEDS OF 50-65 KT FROM CENTRAL OKLAHOMA INTO SOUTHERN MINNESOTA. THESE WINDS WERE TRANSPORTING COPIOUS AMOUNTS OF MOISTURE NORTHWARD...NOTED BY PRECIPITABLE WATER VALUES OF 1.5-1.75 INCHES OR 150-180 PERCENT OF NORMAL. NUMEROUS SHORTWAVES...SOME CONVECTIVELY INDUCED...RIDING THROUGH THE MID LEVEL FLOW HAS BEEN INTERACTING WITH THE MORE SUMMER-LIKE AIRMASS TO CONTINUE TO PRODUCE SCATTERED CLUSTERS OF SHOWERS AND THUNDERSTORMS. MUCH OF THE FORECAST AREA LIES IN THE WARM SECTOR OF A LOW PRESSURE SYSTEM BACK IN THE DAKOTAS. MAIN WARM FRONT HAS LIFTED INTO NORTHERN WISCONSIN WHILE THE COLD FRONT IS WELL BACK TO THE WEST IN CENTRAL SOUTH DAKOTA. MODELS ARE IN GOOD AGREEMENT ON THE SYNOPTICS THROUGH TONIGHT... INDICATING THAT THE UPPER TROUGHING FROM WYOMING INTO THE TEXAS PANHANDLE WILL SHIFT EAST NORTHEAST INTO THE FORECAST AREA BY 06Z TONIGHT. THERE ARE SOME DECENT 500MB HEIGHT FALLS BETWEEN 18Z-06Z OVER THE FORECAST AREA...ON THE ORDER OF 60-90 METERS. THE DPVA FROM THE APPROACH OF THIS UPPER TROUGH...AS WELL AS VARIOUS SHORTWAVES AND CONVECTIVELY INDUCED SHORTWAVES AHEAD OF IT...SUGGESTS PLENTY OF FORCING FOR CONVECTION. MODELS HAVE SHOWN THIS FOR MANY DAYS AS WELL. THIS FORCING MAY MAKE IT HARD TO BUILD A LOT OF INSTABILITY... COMPARED TO YESTERDAY WHERE WE HAD PLENTY OF SUNSHINE BEFORE CONVECTION ERUPTED. RAP/NAM/GFS SOUNDINGS ALL SUGGEST ANY 0-1 MLCIN FROM NOCTURNAL INFLUENCES BEING NEARLY COMPLETELY GONE BY 15Z. THEREFORE IT IS CONCEIVABLE FOR CONVECTION TO FIRE SHORTLY THEREAFTER WHEN 0-1 MLCAPE IS ONLY AT 800-1500 J/KG. HRRR/RAP MODELS SHOW CONVECTION FIRING IN THAT 15-16Z WINDOW...IN AGREEMENT WITH THE ABOVE ANALYSIS. THE CONVECTION MAY STABILIZE THINGS BRIEFLY...BUT PERSISTENT HEATING THROUGH THE DAY COMBINED WITH SOUTHERLY WARM ADVECTION OF INSTABILITY SHOULD PROVIDE FUEL TO CONTINUE PERIODS OF CONVECTION THROUGH THE DAY AND INTO THE EVENING. PASSAGE OF THE UPPER TROUGH AND NOCTURNAL COOLING SHOULD ALLOW CONVECTION TO SUBSIDE AFTER MIDNIGHT. REGARDING SEVERE POTENTIAL...THE LIMITATION OF BUILDING A LOT OF CAPE IS A HINDRANCE. 0-6KM SHEAR FROM THE 30.00Z NAM/GFS IS GENERALLY PROGGED AT 25-30 KT THROUGH THE DAY...FAVORING FOR MORE OF A MULTI-CELL SITUATION. WITH INSTABILITY STRUGGLING...NOT THINKING MUCH IN THE WAY FOR SEVERE HAIL. BULK OF THE AFOREMENTIONED 0-6KM SHEAR IS IN THE 0-3KM LAYER...AND COMBINED WITH 850MB WINDS PROGGED IN THE AFTERNOON AND EVENING OF 45-50 KT DOES BRING UP A CONCERN FOR THE STORMS TO PRODUCE STRONG TO DAMAGING WIND GUSTS. 0-1KM SHEAR IS QUITE HIGH AS WELL FOR THE AFTERNOON AND EVENING...SIMILAR TO 0-3KM OF 25-30KT...SO WE MAY WANT TO WATCH FOR POSSIBLE TORNADOES TOO. THIS WOULD BE ESPECIALLY TRUE ALONG ANY CONVECTIVE OUTFLOW BOUNDARY AND/OR IF WE CAN GET MORE DAYTIME HEATING THAN EXPECTED. ON THE FLOODING FRONT...MORE INFORMATION CAN BE FOUND IN THE HYDROLOGY SECTION BELOW. BRIEFLY...THE PATTERN TODAY INTO THIS EVENING IS VERY FAVORABLE FOR STORMS TO TRAIN ACROSS THE SAME AREAS AS THEY MARCH SOUTH TO NORTH. WITH PRECIPITABLE WATER VALUES STAYING UP IN THE 1.5-1.75 INCH RANGE ANY STORM CAN PRODUCE HEAVY RAIN. WITH GROUNDS ALREADY SATURATED...FLASH FLOODING IS CERTAINLY POSSIBLE... ESPECIALLY SOUTH OF I-90 WHICH WAS REALLY IMPACTED FROM YESTERDAY INTO LAST NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 333 AM CDT THU MAY 30 2013 LOW PRESSURE OVER THE EASTERN DAKOTAS PUSHES SOUTHEAST LATE FRIDAY MORNING INTO FRIDAY AFTERNOON DRIVING THE FRONT ACROSS THE FORECAST AREA. DEPENDING ON THE TIMING OF THIS FRONT...SEVERE WEATHER POSSIBLE ON FRIDAY. FORECAST MODELS ARE IN REASONABLE AGREEMENT...SHOWING 0-3 KM MUCAPE VALUES CLIMBING TO 2000 TO 3000 J/KG. SHEAR IS ALSO RAMPING UP LATE FRIDAY MORNING INTO FRIDAY AFTERNOON WITH 0-6 KM BULK SHEAR INCREASING TO 45 TO 55 KTS. THE HIGHEST INSTABILITY APPEARS TO BE OVER FAR NORTHEAST IOWA AND INTO EXTREME SOUTHWEST WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON THIS OVER THE NEXT FEW MODEL RUNS. AT THIS TIME...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN HAZARDS FROM THESE STORMS. BUT AGAIN...THE SEVERE THREAT AREA WILL DEPEND ON WHERE THE BOUNDARY IS LOCATED LATE FRIDAY MORNING INTO FRIDAY AFTERNOON AND HOW MUCH SURFACE HEATING IS REALIZED. A DRY SLOT PUSHES INTO THE FORECAST AREA LATE FRIDAY NIGHT AS THE LOW PUSHES EAST INTO THE WESTERN GREAT LAKES. THERE SHOULD BE A DRY PERIOD AS THE LOW MOVES IN...BUT THEN SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP ON SATURDAY AS THE LOW SLIDES ACROSS THE REGION. AN UNSEASONABLY COOL AIRMASS MOVES INTO REGION ON SUNDAY. 850 MB TEMPERATURES FALL TO 0 C OVER NORTHERN WISCONSIN AND TO AROUND 2 C OVER NORTHEAST IOWA. THIS WILL SET THE STAGE FOR A CHILLY NIGHT ACROSS THE AREA SUNDAY NIGHT INTO EARLY MONDAY MORNING. ECMWF 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO AROUND -1.5...INDICATIVE OF AN ANOMALOUSLY COLD AIRMASS. TEMPERATURES WILL PLUMMET INTO THE UPPER 30S OVER FAR NORTHERN WISCONSIN. WILL HAVE TO KEEP A VERY CLOSE WATCH ON LOWS OVER NORTH CENTRAL AND CENTRAL WISCONSIN WHERE TYPICAL COLD SPOTS SUCH AS SPARTA AND BLACK RIVER FALLS COULD SEE LOWS DIP INTO THE UPPER 30S...LEADING TO FROST FORMATION. COOL HIGH PRESSURE REMAINS OVER THE REGION THROUGH TUESDAY...WITH HIGHS ONLY IN THE 60S. HIGH PRESSURE PUSHES EAST OF THE REGION LATE TUESDAY INTO WEDNESDAY AS A TROUGH DIGS INTO THE DAKOTAS. SOUTHERLY FLOW DEVELOPS OVER THE AREA HELPING TO USHER IN WARMER TEMPERATURES. THE TROUGH WILL MOVE INTO THE FORECAST AREA LATE TUESDAY NIGHT THROUGH WEDNESDAY BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1225 PM CDT THU MAY 30 2013 FORECAST THIS PERIOD REMAINS DIFFICULT...ESPECIALLY THIS AFTERNOON AND EVENING. ANOTHER ROUND OF MORE WIDESPREAD SHRA/TSRA EXPECTED TO SPREAD ACROSS THE TAF SITES THIS AFTERNOON/EVENING WITH PERIOD OF MVFR CIGS AND IFR/MVFR VSBYS IN STRONGER STORM CORES. GENERALLY LEFT TSRA MENTION IN TAFS FOR THIS AFTERNOON AS VCTS AND CB DUE TO UNCERTAINTIES OF THE TIMING AND TSRA PASSING OVER A TAF SITE. PLAN ON TAF UPDATES AS CONVECTION MODE/TIMING BECOME CLEARER THRU THE AFTERNOON. TIGHT PRESSURE GRADIENT REMAINS OVER THE AREA THIS AFTERNOON FOR SOUTH WINDS 15-20KT G25-30KTS. GRADIENT RELAXES A BIT TONIGHT BUT WIND LOOK TO REMAIN SOUTH 10-15KTS...FOR GOOD BOUNDARY LAYER STIRRING/MIXING TO LIMIT BR FORMATION. ONCE THE MID LEVEL TROUGH AXIS PASSES TONIGHT...SFC TO MID LEVEL FLOW SWINGS A BIT MORE SOUTHWEST...BRINGING SOME SLIGHTLY DRIER AIR INTO THE AREA. GENERALLY SCT030 CLOUDS EXPECTED LATER TONIGHT/FRI MORNING BEHIND THIS PASSING FEATURE. && .HYDROLOGY...TODAY AND TONIGHT ISSUED AT 333 AM CDT THU MAY 30 2013 HEAVY RAIN FELL ACROSS THE AREA WEDNESDAY AFTERNOON AND EVENING WITH RAINFALL AMOUNTS OF 2 TO 3 INCHES REPORTED ACROSS PORTIONS OF NORTHEAST IOWA...SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN...WITH LOCALLY HIGHER AMOUNTS OF 4 INCHES REPORTED. AN ADDITIONAL 1 TO 2 INCHES OF RAIN IS EXPECTED ACROSS THE AREA TODAY THROUGH THIS EVENING...WHICH COULD LEAD TO FLASH FLOODING. IT WILL NOT TAKE MUCH RAIN OVER THE SATURATED SOILS TO CREATE FLOODING ISSUES. ALSO...AREA RIVERS WILL SEE RISES AND POSSIBLE FLOODING WITH ANY ADDITIONAL RAINFALL RECEIVED. HAVE EXPANDED THE FLASH FLOOD WATCH NORTHWARD...INCLUDING AREAS ALONG AND SOUTHWEST OF INTERSTATE 94 CORRIDOR EXCLUDING JUNEAU COUNTY && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WIZ032>034-041-042- 053>055-061. MN...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR IAZ008>011-018-019- 029-030. && $$ SHORT TERM...AJ/WETENKAMP LONG TERM....WETENKAMP AVIATION.....RRS HYDROLOGY....WETENKAMP