Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/27/13


AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1027 PM PDT MON JUN 24 2013 .DISCUSSION...AS OF 9:15 PM PDT MONDAY...KMUX RADAR CONTINUES TO SHOW HIT AND MISS SHOWERS ACROSS THE BAY AREA WITH RAIN TOTALS GENERALLY ON THE LIGHT SIDE SO FAR WITH MOST LOCALES LESS THAN A TENTH OF AN INCH EXCEPT 0.25-0.30 FOR THE SONOMA COAST. AS ONE CAN FEEL THERE IS PLENTY OF AVAILABLE MOISTURE WITH DEWPOINTS HOVERING AROUND 60 DEGREES WITH LAYERED CLOUD DECKS AND EVEN SOME DENSE FOG SHOWING UP AROUND HALF MOON BAY. AS HAS BEEN THE CASE THE LAST 24 HOURS THERE CONTINUES TO BE NO FOCUSED FORCING OR DYNAMICS TO REALLY GENERATE ANY APPRECIABLE PRECIP. ALL OF OUR SHORT TERM MODELS...THE 00Z NAM AS WELL AS THE LATEST IN HOUSE WRF AND NCEP RAP MODEL SHOW THE LAST GOOD CHANCE OF GENERATING NOTEWORTHY RAINFALL WILL OCCUR OVERNIGHT THROUGH THE MORNING HOURS OF TUESDAY. AS HAS BEEN THE CASE ALL ALONG THE NORTH BAY AND IN PARTICULAR SONOMA COUNTY WILL SEE THE BEST SHOT OF RAIN TOTALS IN EXCESS OF 0.50 TO 1 INCH. FROM AN IMPACT STANDPOINT WE CAN EXPECT WET ROADS FOR THE MORNING COMMUTE FOR THE GREATER BAY AREA AS WELL AS THE NORTH BAY WITH THE 101 CORRIDOR AND POINTS NORTHWARD MOST DIRECTLY IMPACTED. ANY RAIN SOUTH OF THE SANTA CRUZ MOUNTAINS LOOKS TO BE SPOTTY AND LIGHT. OF COURSE ANY RAINFALL ON JUNE 25TH IS RARE SO WE SHOULD BE ABLE TO BREAK SOME DAILY RAINFALL RECORDS BEFORE MIDNIGHT TONIGHT AS WELL AS FOR TUESDAY. THE MOST CONSISTENT SITE FOR RECORDS SUCH AS THIS IS DOWNTOWN SF AND THAT DAILY RECORD IS 0.15 BACK IN 2001. IN GENERAL SHOWERS BECOME ISOLATED BY MIDDAY TUESDAY ALTHOUGH CHANCES WILL LINGER IN THE NORTH BAY THROUGH TUESDAY EVENING. THE ABSENCE OF COLD ADVECTION WILL LIKELY LEAD TO MORE LOW CLOUD AND FOG FORMATION TUESDAY NIGHT INTO WEDS MORNING. THERE IS NOTHING TO WASH THE HIGH DEWPOINT AIR OUT WITH SOUTHERLY WINDS STAYING IN PLACE BEHIND THE WARM FRONT. THE LACK OF NW WINDS OVER THE OCEAN WILL KEEP UPWELLING NEARLY NON-EXISTENT AND SST WILL HOVER IN THE UPPER 50S AS WELL. ANYWAY WEDS WILL BE A TRANSITION DAY WITH DRY WEATHER BUT A WARMING AIRMASS. THE HIGH DEWPOINTS WILL KEEP THINGS ALMOST UNCOMFORTABLE FOR THOSE FOLKS NOT ACCUSTOMED TO THE HEAT. LUCKILY BY THURSDAY AS THE RIDGE REALLY STARTS TO BUILD IN WE SHOULD GET A RETURN OF NW WIND FLOW. A DOMINANT WESTERN US RIDGE WILL BECOME THE MAIN WEATHER STORY FOR THE ENTIRE WESTERN HALF OF THE COUNTRY WITH BIG TIME HEAT FOR MOST OF THE WESTERN HALF OF THE US. THE INLAND LOCATIONS WILL RAPIDLY WARM WHILE THE COAST WILL KEEP A MARINE LAYER IN PLACE AT LEAST HEADING INTO THE WEEKEND. THERE ARE SOME INDICATIONS THAT THE RIDGE COULD BUILD TOWARDS CALIFORNIA AND ESSENTIALLY PUSH THE SURFACE THERMAL TROUGH NEAR THE COAST WITH HOT WEATHER PUSHING CLOSE TO THE BEACHES BY EARLY NEXT WEEK. LOOKS HOT AND DRY HEADING INTO THE FOURTH OF JULY HOLIDAY FOR MOST OF THE STATE. && .AVIATION...AS OF 10:30 PM PDT MONDAY...A VERY MOIST AIRMASS WILL REMAIN OVER THE AREA TONIGHT AND TUESDAY. LIGHT WINDS AND INCREASING LOW LEVEL STABILITY TONIGHT FAVORS IFR CEILINGS AND VISIBILITIES. VICINITY OF KSFO...VFR/MVFR CONDITIONS WILL LIKELY TREND TO IFR OVERNIGHT. SURFACE WINDS WILL KICK UP A LITTLE BY MID-LATE TUESDAY MORNING WHICH SHOULD HELP LIFT CEILINGS AND VISIBILITIES BACK TO MVFR AFTER 18Z. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...EXPECT IFR TONIGHT WITH OCCASIONAL LIGHT DRIZZLE. CEILINGS GRADUALLY LIFT BACK TO MVFR BY 17Z TUESDAY. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...NONE. $$ 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 SAN FRANCISCO BAY AREA
915 PM PDT MON JUN 24 2013 .DISCUSSION...AS OF 9:15 PM PDT MONDAY...KMUX RADAR CONTINUES TO SHOW HIT AND MISS SHOWERS ACROSS THE BAY AREA WITH RAIN TOTALS GENERALLY ON THE LIGHT SIDE SO FAR WITH MOST LOCALES LESS THAN A TENTH OF AN INCH EXCEPT 0.25-0.30 FOR THE SONOMA COAST. AS ONE CAN FEEL THERE IS PLENTY OF AVAILABLE MOISTURE WITH DEWPOINTS HOVERING AROUND 60 DEGREES WITH LAYERED CLOUD DECKS AND EVEN SOME DENSE FOG SHOWING UP AROUND HALF MOON BAY. AS HAS BEEN THE CASE THE LAST 24 HOURS THERE CONTINUES TO BE NO FOCUSED FORCING OR DYNAMICS TO REALLY GENERATE ANY APPRECIABLE PRECIP. ALL OF OUR SHORT TERM MODELS...THE 00Z NAM AS WELL AS THE LATEST IN HOUSE WRF AND NCEP RAP MODEL SHOW THE LAST GOOD CHANCE OF GENERATING NOTEWORTHY RAINFALL WILL OCCUR OVERNIGHT THROUGH THE MORNING HOURS OF TUESDAY. AS HAS BEEN THE CASE ALL ALONG THE NORTH BAY AND IN PARTICULAR SONOMA COUNTY WILL SEE THE BEST SHOT OF RAIN TOTALS IN EXCESS OF 0.50 TO 1 INCH. FROM AN IMPACT STANDPOINT WE CAN EXPECT WET ROADS FOR THE MORNING COMMUTE FOR THE GREATER BAY AREA AS WELL AS THE NORTH BAY WITH THE 101 CORRIDOR AND POINTS NORTHWARD MOST DIRECTLY IMPACTED. ANY RAIN SOUTH OF THE SANTA CRUZ MOUNTAINS LOOKS TO BE SPOTTY AND LIGHT. OF COURSE ANY RAINFALL ON JUNE 25TH IS RARE SO WE SHOULD BE ABLE TO BREAK SOME DAILY RAINFALL RECORDS BEFORE MIDNIGHT TONIGHT AS WELL AS FOR TUESDAY. THE MOST CONSISTENT SITE FOR RECORDS SUCH AS THIS IS DOWNTOWN SF AND THAT DAILY RECORD IS 0.15 BACK IN 2001. IN GENERAL SHOWERS BECOME ISOLATED BY MIDDAY TUESDAY ALTHOUGH CHANCES WILL LINGER IN THE NORTH BAY THROUGH TUESDAY EVENING. THE ABSENCE OF COLD ADVECTION WILL LIKELY LEAD TO MORE LOW CLOUD AND FOG FORMATION TUESDAY NIGHT INTO WEDS MORNING. THERE IS NOTHING TO WASH THE HIGH DEWPOINT AIR OUT WITH SOUTHERLY WINDS STAYING IN PLACE BEHIND THE WARM FRONT. THE LACK OF NW WINDS OVER THE OCEAN WILL KEEP UPWELLING NEARLY NON-EXISTENT AND SST WILL HOVER IN THE UPPER 50S AS WELL. ANYWAY WEDS WILL BE A TRANSITION DAY WITH DRY WEATHER BUT A WARMING AIRMASS. THE HIGH DEWPOINTS WILL KEEP THINGS ALMOST UNCOMFORTABLE FOR THOSE FOLKS NOT ACCUSTOMED TO THE HEAT. LUCKILY BY THURSDAY AS THE RIDGE REALLY STARTS TO BUILD IN WE SHOULD GET A RETURN OF NW WIND FLOW. A DOMINANT WESTERN US RIDGE WILL BECOME THE MAIN WEATHER STORY FOR THE ENTIRE WESTERN HALF OF THE COUNTRY WITH BIG TIME HEAT FOR MOST OF THE WESTERN HALF OF THE US. THE INLAND LOCATIONS WILL RAPIDLY WARM WHILE THE COAST WILL KEEP A MARINE LAYER IN PLACE AT LEAST HEADING INTO THE WEEKEND. THERE ARE SOME INDICATIONS THAT THE RIDGE COULD BUILD TOWARDS CALIFORNIA AND ESSENTIALLY PUSH THE SURFACE THERMAL TROUGH NEAR THE COAST WITH HOT WEATHER PUSHING CLOSE TO THE BEACHES BY EARLY NEXT WEEK. LOOKS HOT AND DRY HEADING INTO THE FOURTH OF JULY HOLIDAY FOR MOST OF THE STATE. && .AVIATION...AS OF 5:20 PM PDT MONDAY...ABUNDANT MOISTURE IS AROUND THE ENTIRE AREA PER WEATHER OBS...SATELLITE AND RADAR DATA. WINDS ARE EXPECTED TO REMAIN MOSTLY LIGHT THROUGH THE EVENING AND OVERNIGHT AT 10 KNOTS OR LESS. THE MAIN CONCERN TONIGHT IS THE POTENTIAL FOR IFR AND THE RATE AT WHICH IT DEVELOPS. THE JET STREAM IS BEGINNING TO DEPART AND LIFT NORTH AWAY FROM THE AREA HOWEVER A LOW LEVEL WARM AIR ADVECTION DEVELOPS AND PROVIDES THE LIFT NEEDED FOR ADDITIONAL RAIN OR DRIZZLE TONIGHT. A SURFACE TROUGH ARRIVES JUST AFTER DAYBREAK TUESDAY. MODELS ALSO FORECAST STEADILY INCREASING 500 MB HEIGHTS TONIGHT AND TUESDAY SUGGESTING GREATER AIRMASS STABILITY THAN LAST NIGHT WHICH SUGGESTS GREATER IFR POTENTIAL. VICINITY OF KSFO...CIGS HAVE SLIPPED A BIT LOWER IN THE LAST HOUR PER METAR OBS...BUT THERE REMAINS MODERATE CONFIDENCE THAT MVFR/VFR WILL HOLD FOR THE EVENING. ONSET OF NIGHT HOURS...VERY MOIST AIRMASS...LIGHT SURFACE WINDS...LIGHT PRECIPITATION AND STEADILY INCREASING AIRMASS STABILITY OVERNIGHT AND TUESDAY LEADS TO SOME CONCERN FOR IFR POTENTIAL LATE AT NIGHT AND TUE MORNING. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...MODERATE CONFIDENCE MVFR/VFR CONDITIONS ARE EXPECTED THIS EVENING. STEADILY LOWERING CIGS ARE EXPECTED AFTER 06Z WITH OCCASIONAL LIGHT RAIN OR DRIZZLE. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...NONE. $$ 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 TAUNTON MA
447 PM EDT TUE JUN 25 2013 .SYNOPSIS... WARM AND MUGGY CONDITIONS WILL CONTINUE AS SHOWERS AND THUNDERSTORMS BECOME MORE WIDESPREAD INTO THE END OF THE WEEK. WHILE HEAVY RAIN WITH POTENTIAL LOCALIZED FLOODING IS THE PRIMARY THREAT...STRONG THUNDERSTORMS WILL BE POSSIBLE AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST THIS WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... *** HEAT AND HUMIDITY CONTINUE INTO TODAY *** *** THUNDERSTORMS WITH HEAVY DOWNPOURS POSSIBLE *** 2 PM UPDATE...TEMPERATURES ARE IN THE UPPER 80S AND LOWER 90S ACROSS MUCH OF THE AREA...WITH MID 80S EVEN ON THE OUTER CAPE AND MARTHAS VINEYARD. WHILE TEMPERATURES ARE DEFINITELY HOT...WE ARE NOT IN DANGER OF HITTING THE RECORDS TODAY. BOTH BOSTON AND HARTFORD HAVE HIT 90 DEGREES FOR THE THIRD DAY IN A ROW MAKING IT AN OFFICIAL HEAT WAVE AT THOSE TWO SITES. OUR TWO OTHER OFFICIAL CLIMATE STATIONS...WORCESTER AND PROVIDENCE...HAVE NOT YET HAD A HEAT WAVE. WORCESTER HAS NOT HAD ANY HIGH TEMPERATURES OVER 90 DEGREES AND PROVIDENCE HAS HIT 90 DEGREES FOR ONLY THE SECOND DAY IN A ROW. THE CONVECTIVE TEMPERATURE ACROSS THE AREA IS ALSO IN THE UPPER 80S TO LOWER 90S SO SHOWERS AND THUNDERSTORMS ARE LIKELY TO DEVELOP AS WE GO THROUGH THE AFTERNOON. STORMS HAVE ALREADY POPPED ACROSS MUCH OF NEW YORK STATE AND PORTIONS OF NORTHERN NEW ENGLAND. SPC MESOANALYSIS HAS UP TO 3000 J/KG OF SB CAPE ACROSS MUCH OF THE AREA WITH LITTLE TO NO CONVECTIVE INHIBITION. LIKE YESTERDAY... THERE IS VERY LITTLE SHEAR. BETWEEN THIS AND A LACK OF A GOOD TRIGGER LIKE A SHORTWAVE OR A FRONT...EXPECT THE THREATS FROM THESE STORMS TO MAINLY BE HEAVY RAIN AND FREQUENT LIGHTNING. PRECIPITABLE WATER VALUES ARE FORECAST TO INCREASE TO BETWEEN 1.5 AND 2 INCHES WHICH IS 2 TIMES THE NORMAL. THERE IS A LOW PROBABILITY OF STRONG WIND GUSTS TO 50 MPH AND PEA SIZE HAIL WITH ANY OF THESE STORMS. THE HRRR MODEL STILL SHOWS A CONVECTIVE LINE MOVING THROUGH SOUTHERN NEW ENGLAND BETWEEN 21-01Z. FROM JUST THE INSTABILITY AND SHEAR AVAILABLE...WOULD HAVE LOW CONFIDENCE ON THIS LINE DEVELOPING. HOWEVER...THE HRRR IS DOING A GREAT JOB WITH THE CONVECTION ACROSS NEW YORK STATE SO TEND TO HAVE A BIT MORE CONFIDENCE IN THAT MODELS SOLUTION. HIGHEST CONFIDENCE IS ACROSS NORTHERN MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE CLOSER TO A WEAK SHORTWAVE MOVING THROUGH QUEBEC. && .SHORT TERM /10 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... TONIGHT...ANY LINGERING SHOWERS AND THUNDERSTORMS WILL DIMINISH LATE TONIGHT. WILL BE ANOTHER WARM AND MUGGY NIGHT WITH LOW TEMPERATURES IN THE UPPER 60S TO THE LOWER 70S. FOG IS A POSSIBILITY AGAIN TONIGHT WITH THE BEST CHANCE ACROSS THE SOUTH COAST...CAPE...AND ISLANDS. WEDNESDAY...SHOWERS AND THUNDERSTORMS ARE LIKELY ONCE AGAIN. THERE IS ACTUALLY A BETTER CHANCE WEDNESDAY THAN TODAY WITH A SHORTWAVE MOVING ACROSS SOUTHERN NEW ENGLAND INCREASING SHEAR AND PROVIDING A TRIGGER. THE HEAT AND HUMIDITY SHOULD CONTINUE WHICH WILL KEEP CAPE VALUES HIGH. SO WITH PLENTY OF INSTABILITY...25 TO 30 KTS OF SHEAR AND PLENTY OF MOISTURE WITH PWATS UP TO 2 INCHES...EXPECT THUNDERSTORMS WITH HEAVY RAIN AND STRONG TO DAMAGING WINDS. TEMPERATURES WILL BE A BIT COOLER...PARTICULARLY ACROSS THE NORTHERN ZONES WHERE A BACK DOOR COLD FRONT MAY TRY TO EDGE IN. EXPECT HIGHEST TEMPERATURES IN THE UPPER 80S TO LOW 90S ALONG AND SOUTH OF THE MASS PIKE AND SLIGHTLY COOLER TEMPERATURES NORTH OF THE MASS PIKE WITH HIGHS IN THE MID 80S. WEDNESDAY NIGHT...COOLER TEMPERATURE TREND WILL CONTINUE WITH THE BACK DOOR FRONT CONTINUING TO MOVE SOUTHWARD THROUGH SOUTHERN NEW ENGLAND. EXPECT OVERNIGHT LOWS IN THE MID TO UPPER 60S. ANY CONVECTION DURING THE DAY WILL LIKELY CONTINUE FOR MUCH OF THE NIGHT WITH LIFT PROVIDED BY THE SHORTWAVE AND THE BACK DOOR FRONT. HEAVY RAIN AND ANY URBAN AND POOR DRAINAGE FLOODING WILL BE THE MAIN CONCERNS OVERNIGHT...THOUGH STRONG GUSTY WINDS AND SMALL HAIL CANNOT BE RULED OUT. ONCE AGAIN...FOG IS LIKELY...PARTICULARLY ALONG THE SOUTH COAST. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HEADLINES... * HEAVY RAIN THREAT PREVAILS THROUGH MOST OF THIS TIMEFRAME * LOCALIZED URBAN AND LOW LYING AREA FLOODING IS A POSSIBILITY * STRONG THUNDERSTORMS POSSIBLE THURSDAY * CONTINUED WARM AND MUGGY CONDITIONS OVERVIEW AND MODEL PREFERENCES... MEDIUM RANGE MODELS CONTINUE TO SIGNAL HIGHLY ANOMALOUS UPPER LEVEL BLOCKING PATTERN FOR EARLY SUMMER...WITH HIGH AMPLITUDE RIDGE ACROSS THE WESTERN U.S. AND LONG WAVE TROUGH ACROSS THE E. THIS WILL KEEP THE REGION IN A RELATIVELY UNSETTLED PATTERN THANKS TO THE UPPER TROUGH/CUTOFF LOW NEAR OR TO THE W OF THE REGION...THOUGH SOME MODELS ARE TRYING TO RETROGRADE THE TROUGH A BIT FURTHER W LATE IN THE PERIOD /MON- TUE/ TO PUSH THREAT OF SHOWERS FURTHER W. ALSO NOTING SOME BRIEF BREAKS IN THE ACTION...MAINLY AROUND THE LATE THU-FRI TIMEFRAME AS SEEN ON 12Z OP RUNS OF THE GFS/GGEM AND ECMWF. THIS IS JUST ONE RUN...THOUGH...SO NOT VERY CONFIDENT. WILL STILL SEE PROLONGED PERIOD OF WARM AND HUMID CONDITIONS. WITH HIGH PWATS...ON THE ORDER OF 1.7 TO AROUND 2 INCHES WITH PROLONGED S-SW FLOW IN PLACE...EXPECT ANY SHOWERS/TSTMS TO PRODUCE LOCALLY HEAVY RAINFALL ESPECIALLY THU AND FRI. WILL NOT SEE A COMPLETE WASHOUT...BUT MAY SEE PERIODS OF SHOWERS/TSTMS EACH DAY. BY THIS WEEKEND...COULD SEE SOME GRADUAL IMPROVEMENT BUT THIS WILL BE DEPENDENT UPON WHETHER THE TROUGH ACTUALLY RETROGRADE AS MODELS ARE SUGGESTING. LEANED TOWARD A BLEND OF THE PREVIOUS FORECAST WITH THE WPC GUIDANCE...WHICH USED A BLEND OF THE GFS/ECMWF AND THEIR ENSEMBLE MEANS. THIS GAVE GOOD CONTINUITY TO THE LAST SEVERAL FORECASTS. DETAILS... THURSDAY-FRIDAY...CONTINUED THREAT OF SHOWERS/TSTMS DURING THIS TIMEFRAME. BEST INSTABILITY WILL BE ACROSS CENTRAL AND WESTERN AREAS THU INTO FRI MORNING SO HAVE KEPT LIKELY POPS GOING THERE. WILL ALSO SEE HEAVY RAINFALL AND POSSIBLE LOCALIZED FLOODING... THOUGH TOUGH TO PINPOINT WHERE THESE WILL OCCUR. DURING THE DAY FRIDAY INTO FRIDAY NIGHT...MAY SEE LESSER OF A CHANCE OF PRECIP AS BRIEF LULL MOVES ACROSS. WITH HIGH HUMIDITIES...CAN NOT RULE OUT THE CHANCE OF PRECIP THOUGH SO LEFT LOW CHANCE POPS GOING. WILL ALSO SEE PATCHY FOG DEVELOP EACH NIGHT/EARLY MORNING TIMEFRAME ESPECIALLY ALONG THE S COAST WITH SUCH MUGGY CONDITIONS IN PLACE. MAY SEE GUSTY WINDS ALONG THE S COAST FRIDAY AS S-SW LOW LEVEL JET SETS UP. GUSTS UP TO 25-30 KT POSSIBLE. SATURDAY-TUESDAY...WILL SEE CONTINUED CHANCE POPS FOR MOST OF THIS TIMEFRAME...THOUGH MAY SEE A SLOWLY LOWER CHANCE MON-TUE IF THE MODELS VERIFY AND TRY TO RETROGRADE INSTABILITY AXIS TO THE W. KEPT MENTION OF TSTMS MAINLY DURING THE DAYLIGHT HOURS THIS WEEKEND...THEN MOVED IT W EARLY NEXT WEEK. LOW LEVEL JET IN PLACE ON SAT MAY BRING GUSTS ALONG THE S COAST UP TO 25 KT. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH WEDNESDAY NIGHT...MODERATE CONFIDENCE. THROUGH 00Z...MAINLY VFR. AFTER 21Z...PATCHY MVFR/IFR CONDITIONS IN SCT SHRA/TSRA. TONIGHT...MAINLY VFR. SCT SHRA/TSRA CONTINUES TO MOVE EAST THROUGH 06Z RESULTING IN BRIEF MVFR/IFR CONDITIONS. MVFR/IFR STRATUS AND FOG LIKELY ALONG THE SOUTH COAST. WEDNESDAY...ANOTHER ROUND OF SHRA/TSRA IN THE AFTERNOON HOURS. GUSTY WINDS AND REDUCED VSBYS GREATEST THREATS. WEDNESDAY NIGHT...SCT SHRA/TSRA POSSIBLE DURING THE EVENING HOURS. LOW CLOUDS/FOG POSSIBLE AGAIN ALONG THE SOUTH COAST WITH MVFR/IFR CONDITIONS. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. OUTLOOK...THURSDAY THROUGH SUNDAY... THURSDAY...BEST CHANCE FOR SHRA/TSRA REMAINS ACROSS INTERIOR NEW ENGLAND. LOCAL +RA EXPECTED. GUSTY WINDS POSSIBLE...BEST CHANCE ALONG S COAST. LOW END VFR TO MVFR CIGS WITH CB ALONG WITH MVFR- IFR VSBYS POSSIBLE IN PATCHY FOG MAINLY THU NIGHT. PREVAILING S-SW WINDS. LLWS POSSIBLE THU NIGHT MAINLY ACROSS S COASTAL AREAS. FRIDAY...SHRA/TSRA REMAIN MORE WIDESPREAD ACROSS CENTRAL AND WESTERN AREAS WITH CHANCE POPS CONTINUING OVER THE EAST EARLY. MAY SEE BRIEF LULL IN ACTION LATE FRI/FRI NIGHT...THOUGH PATCHY FOG WITH MVFR-IFR VSBYS WILL CONTINUE. GUSTY S-SW WINDS POSSIBLE. LLWS POSSIBLE ACROSS S COASTAL AREAS. SATURDAY-SUNDAY...CONTINUED CHANCE FOR SHRA/TSRA OFF AND ON THROUGH THIS TIMEFRAME. GUSTY S-SW WINDS POSSIBLE. LOW END VFR TO MVFR CIGS WITH CB ALONG WITH MVFR-IFR VSBYS POSSIBLE. PREVAILING SW WINDS. LLWS POSSIBLE SAT ACROSS S COASTAL AREAS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH WEDNESDAY NIGHT...HIGH CONFIDENCE. TODAY THROUGH WEDNESDAY NIGHT... ESSENTIALLY...EXPECTING A REPEAT OF TODAY AND LAST NIGHT. WINDS AND SEAS GENERALLY REMAIN BELOW SMALL CRAFT CRITERIA THOUGH SEAS MAY RISE TO ABOUT 5 FEET ON THE OUTER WATERS. FOG WILL DEVELOP OVERNIGHT AND THEN BURN OFF BY MIDDAY AND GIVE WAY TO LATE DAY TSTMS. MAIN THREATS HEAVY RAIN AND FREQUENT LIGHTNING. OUTLOOK...THURSDAY THROUGH SATURDAY... S-SW WINDS GUSTING UP TO 25 KT AT TIMES...MAINLY THU NIGHT THROUGH SUNDAY. LONG SOUTH TO SOUTHWEST FETCH WILL BRING SEAS UP TO 5-8 FT ACROSS THE OUTER COASTAL WATERS...POSSIBLY INTO RI AND BLOCK ISLAND SOUNDS AS WELL. SCATTERED SHOWERS/TSTMS...MAINLY DURING THE AFTERNOON/EVENING HOURS. HEAVY RAIN AND FREQUENT LIGHTNING IN ANY STORMS. PATCHY FOG WITH REDUCED VSBYS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...AIR QUALITY ALERT UNTIL 10 PM EDT THIS EVENING FOR MAZ020>024. NH...NONE. RI...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008. MARINE...NONE. && $$ SYNOPSIS...RLG/EVT NEAR TERM...RLG SHORT TERM...RLG LONG TERM...EVT AVIATION...RLG/EVT MARINE...RLG/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
304 PM EDT TUE JUN 25 2013 .SYNOPSIS... WARM AND MUGGY CONDITIONS WILL CONTINUE AS SHOWERS AND THUNDERSTORMS BECOME MORE WIDESPREAD INTO THE END OF THE WEEK. WHILE HEAVY RAIN WITH POTENTIAL LOCALIZED FLOODING IS THE PRIMARY THREAT...STRONG THUNDERSTORMS WILL BE POSSIBLE AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST THIS WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... *** HEAT AND HUMIDITY CONTINUE INTO TODAY *** *** THUNDERSTORMS WITH HEAVY DOWNPOURS POSSIBLE *** 2 PM UPDATE...TEMPERATURES ARE IN THE UPPER 80S AND LOWER 90S ACROSS MUCH OF THE AREA...WITH MID 80S EVEN ON THE OUTER CAPE AND MARTHAS VINEYARD. WHILE TEMPERATURES ARE DEFINITELY HOT...WE ARE NOT IN DANGER OF HITTING THE RECORDS TODAY. BOTH BOSTON AND HARTFORD HAVE HIT 90 DEGREES FOR THE THIRD DAY IN A ROW MAKING IT AN OFFICIAL HEAT WAVE AT THOSE TWO SITES. OUR TWO OTHER OFFICIAL CLIMATE STATIONS...WORCESTER AND PROVIDENCE...HAVE NOT YET HAD A HEAT WAVE. WORCESTER HAS NOT HAD ANY HIGH TEMPERATURES OVER 90 DEGREES AND PROVIDENCE HAS HIT 90 DEGREES FOR ONLY THE SECOND DAY IN A ROW. THE CONVECTIVE TEMPERATURE ACROSS THE AREA IS ALSO IN THE UPPER 80S TO LOWER 90S SO SHOWERS AND THUNDERSTORMS ARE LIKELY TO DEVELOP AS WE GO THROUGH THE AFTERNOON. STORMS HAVE ALREADY POPPED ACROSS MUCH OF NEW YORK STATE AND PORTIONS OF NORTHERN NEW ENGLAND. SPC MESOANALYSIS HAS UP TO 3000 J/KG OF SB CAPE ACROSS MUCH OF THE AREA WITH LITTLE TO NO CONVECTIVE INHIBITION. LIKE YESTERDAY... THERE IS VERY LITTLE SHEAR. BETWEEN THIS AND A LACK OF A GOOD TRIGGER LIKE A SHORTWAVE OR A FRONT...EXPECT THE THREATS FROM THESE STORMS TO MAINLY BE HEAVY RAIN AND FREQUENT LIGHTNING. PRECIPITABLE WATER VALUES ARE FORECAST TO INCREASE TO BETWEEN 1.5 AND 2 INCHES WHICH IS 2 TIMES THE NORMAL. THERE IS A LOW PROBABILITY OF STRONG WIND GUSTS TO 50 MPH AND PEA SIZE HAIL WITH ANY OF THESE STORMS. THE HRRR MODEL STILL SHOWS A CONVECTIVE LINE MOVING THROUGH SOUTHERN NEW ENGLAND BETWEEN 21-01Z. FROM JUST THE INSTABILITY AND SHEAR AVAILABLE...WOULD HAVE LOW CONFIDENCE ON THIS LINE DEVELOPING. HOWEVER...THE HRRR IS DOING A GREAT JOB WITH THE CONVECTION ACROSS NEW YORK STATE SO TEND TO HAVE A BIT MORE CONFIDENCE IN THAT MODELS SOLUTION. HIGHEST CONFIDENCE IS ACROSS NORTHERN MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE CLOSER TO A WEAK SHORTWAVE MOVING THROUGH QUEBEC. && .SHORT TERM /10 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... TONIGHT...ANY LINGERING SHOWERS AND THUNDERSTORMS WILL DIMINISH LATE TONIGHT. WILL BE ANOTHER WARM AND MUGGY NIGHT WITH LOW TEMPERATURES IN THE UPPER 60S TO THE LOWER 70S. FOG IS A POSSIBILITY AGAIN TONIGHT WITH THE BEST CHANCE ACROSS THE SOUTH COAST...CAPE...AND ISLANDS. WEDNESDAY...SHOWERS AND THUNDERSTORMS ARE LIKELY ONCE AGAIN. THERE IS ACTUALLY A BETTER CHANCE WEDNESDAY THAN TODAY WITH A SHORTWAVE MOVING ACROSS SOUTHERN NEW ENGLAND INCREASING SHEAR AND PROVIDING A TRIGGER. THE HEAT AND HUMIDITY SHOULD CONTINUE WHICH WILL KEEP CAPE VALUES HIGH. SO WITH PLENTY OF INSTABILITY...25 TO 30 KTS OF SHEAR AND PLENTY OF MOISTURE WITH PWATS UP TO 2 INCHES...EXPECT THUNDERSTORMS WITH HEAVY RAIN AND STRONG TO DAMAGING WINDS. TEMPERATURES WILL BE A BIT COOLER...PARTICULARLY ACROSS THE NORTHERN ZONES WHERE A BACK DOOR COLD FRONT MAY TRY TO EDGE IN. EXPECT HIGHEST TEMPERATURES IN THE UPPER 80S TO LOW 90S ALONG AND SOUTH OF THE MASS PIKE AND SLIGHTLY COOLER TEMPERATURES NORTH OF THE MASS PIKE WITH HIGHS IN THE MID 80S. WEDNESDAY NIGHT...COOLER TEMPERATURE TREND WILL CONTINUE WITH THE BACK DOOR FRONT CONTINUING TO MOVE SOUTHWARD THROUGH SOUTHERN NEW ENGLAND. EXPECT OVERNIGHT LOWS IN THE MID TO UPPER 60S. ANY CONVECTION DURING THE DAY WILL LIKELY CONTINUE FOR MUCH OF THE NIGHT WITH LIFT PROVIDED BY THE SHORTWAVE AND THE BACK DOOR FRONT. HEAVY RAIN AND ANY URBAN AND POOR DRAINAGE FLOODING WILL BE THE MAIN CONCERNS OVERNIGHT...THOUGH STRONG GUSTY WINDS AND SMALL HAIL CANNOT BE RULED OUT. ONCE AGAIN...FOG IS LIKELY...PARTICULARLY ALONG THE SOUTH COAST. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HEADLINES... * HEAVY RAIN THREAT PREVAILS THROUGHOUT THIS TIMEFRAME * LOCALIZED URBAN AND LOW LYING AREA FLOODING IS A POSSIBILITY * STRONG THUNDERSTORMS POSSIBLE LATE THIS WEEK INTO NEXT MONDAY * CONTINUED WARM AND MUGGY CONDITIONS 25/00Z GUIDANCE CONTINUES TO EXHIBIT OVERALL AGREEMENT WITH THEIR SYNOPTIC SOLUTIONS. THERE REMAIN SOME DETAIL DIFFERENCES...WHICH WILL TAKE SOME TIME TO RESOLVE BASED ON THE NATURE OF THE EXPECTED PATTERN FOR MOST OF THIS WEEK. HAVE LOWER CONFIDENCE IN THE DETAILS OF ANY PARTICULAR SOLUTION AT THIS TIME. AS SUCH...FOLLOWED A CONSENSUS BLEND TO MINIMIZE THE DETAIL DIFFERENCES. IT APPEARS SOUTHERN NEW ENGLAND IS IN FOR A PROLONGED STRETCH OF UNSETTLED WEATHER OVER THE NEXT SEVERAL DAYS. A MID-LEVEL BLOCKING PATTERN IS EXPECTED TO ESTABLISH ITSELF ACROSS THE NORTHERN HALF OF THE CONUS...PLACING OUR REGION JUST EAST OF A MID-LEVEL TROUGH. AT THE SURFACE...THIS WOULD MAINTAIN A GENERAL SOUTHERLY FLOW INTO THIS WEEKEND ALONG WITH HIGH HUMIDITY. TEMPERATURES SHOULD GRADUALLY MODERATE AS CLOUDS BECOME MORE PREVALENT LATE THIS WEEK. AM NOT EXPECTING A COMPLETE WASHOUT...BUT FINDING IT TOUGH TO FIND A DAY WITHOUT A CHANCE OF SHOWERS OR THUNDERSTORMS AT SOME POINT. HIGH HUMIDITY WILL POSE A RISK FOR LOCALIZED HEAVY RAINFALL IN STRONGER SHOWERS AND THUNDERSTORMS INTO EARLY NEXT WEEK. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH WEDNESDAY NIGHT...MODERATE CONFIDENCE. THROUGH 00Z...MAINLY VFR. AFTER 21Z...PATCHY MVFR/IFR CONDITIONS IN SCT SHRA/TSRA. TONIGHT...MAINLY VFR. SCT SHRA/TSRA CONTINUES TO MOVE EAST THROUGH 06Z RESULTING IN BRIEF MVFR/IFR CONDITIONS. MVFR/IFR STRATUS AND FOG LIKELY ALONG THE SOUTH COAST. WEDNESDAY...ANOTHER ROUND OF SHRA/TSRA IN THE AFTERNOON HOURS. GUSTY WINDS AND REDUCED VSBYS GREATEST THREATS. WEDNESDAY NIGHT...SCT SHRA/TSRA POSSIBLE DURING THE EVENING HOURS. LOW CLOUDS/FOG POSSIBLE AGAIN ALONG THE SOUTH COAST WITH MVFR/IFR CONDITIONS. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. OUTLOOK...THURSDAY THROUGH SATURDAY... THURSDAY...SHRA/TSRA LOOK TO REMAIN CONFINED ACROSS INTERIOR NEW ENGLAND. LOCAL +RA EXPECTED. GUSTY WINDS POSSIBLE. LOW-VFR TO MVFR CIGS WITH CB ALONG WITH MVFR-IFR VSBYS POSSIBLE. PREVAILING S-SW WINDS. LLWS POSSIBLE THU NIGHT MAINLY ACROSS S COASTAL AREAS. FRIDAY AND SATURDAY... SHRA/TSRA WILL BE MORE WIDESPREAD ACROSS MOST OF SOUTHERN NEW ENGLAND...WITH THE BEST CHANCE ACROSS CENTRAL AND WESTERN AREAS. +RA EXPECTED WITH GUSTY WINDS POSSIBLE. LOW-VFR TO MVFR CIGS WITH CB ALONG WITH MVFR-IFR VSBYS POSSIBLE. PREVAILING SW WINDS. LLWS MAY BE POSSIBLE FRI THROUGH SAT ACROSS S COASTAL AREAS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH WEDNESDAY NIGHT...HIGH CONFIDENCE. TODAY THROUGH WEDNESDAY NIGHT... ESSENTIALLY...EXPECTING A REPEAT OF TODAY AND LAST NIGHT. WINDS AND SEAS GENERALLY REMAIN BELOW SMALL CRAFT CRITERIA THOUGH SEAS MAY RISE TO ABOUT 5 FEET ON THE OUTER WATERS. FOG WILL DEVELOP OVERNIGHT AND THEN BURN OFF BY MIDDAY AND GIVE WAY TO LATE DAY TSTMS. MAIN THREATS HEAVY RAIN AND FREQUENT LIGHTNING. OUTLOOK...THURSDAY THROUGH SATURDAY... SOUTH TO SOUTHWEST WINDS MAY GUST UP TO 25 KT AT TIMES...MAINLY FRIDAY INTO SATURDAY. LONG SOUTH TO SOUTHWEST FETCH WILL BRING SEAS UP TO 5-8 FT ACROSS THE OUTER COASTAL WATERS...POSSIBLY INTO RI AND BLOCK ISLAND SOUNDS AS WELL. SCATTERED SHOWERS/TSTMS... MAINLY DURING THE AFTERNOON/EVENING HOURS. HEAVY RAIN AND FREQUENT LIGHTNING IN ANY STORMS. PATCHY FOG WITH REDUCED VSBYS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...AIR QUALITY ALERT UNTIL 10 PM EDT THIS EVENING FOR MAZ020>024. NH...NONE. RI...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008. MARINE...NONE. && $$ SYNOPSIS...BELK/RLG NEAR TERM...RLG SHORT TERM...RLG LONG TERM...BELK AVIATION...BELK/RLG MARINE...BELK/RLG
AREA FORECAST DISCUSSION
NWS TAUNTON MA
154 PM EDT TUE JUN 25 2013 .SYNOPSIS... WARM AND MUGGY CONDITIONS WILL CONTINUE AS SHOWERS AND THUNDERSTORMS BECOME MORE WIDESPREAD INTO THE END OF THE WEEK. WHILE HEAVY RAIN WITH POTENTIAL LOCALIZED FLOODING IS THE PRIMARY THREAT...STRONG THUNDERSTORMS WILL BE POSSIBLE AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST THIS WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... *** HEAT AND HUMIDITY CONTINUE INTO TODAY *** *** THUNDERSTORMS WITH HEAVY DOWNPOURS POSSIBLE *** 2 PM UPDATE...TEMPERATURES ARE IN THE UPPER 80S AND LOWER 90S ACROSS MUCH OF THE AREA...WITH MID 80S EVEN ON THE OUTER CAPE AND MARTHAS VINEYARD. WHILE TEMPERATURES ARE DEFINITELY HOT...WE ARE NOT IN DANGER OF HITTING THE RECORDS TODAY. BOTH BOSTON AND HARTFORD HAVE HIT 90 DEGREES FOR THE THIRD DAY IN A ROW MAKING IT AN OFFICIAL HEAT WAVE AT THOSE TWO SITES. OUR TWO OTHER OFFICIAL CLIMATE STATIONS...WORCESTER AND PROVIDENCE...HAVE NOT YET HAD A HEAT WAVE. WORCESTER HAS NOT HAD ANY HIGH TEMPERATURES OVER 90 DEGREES AND PROVIDENCE HAS HIT 90 DEGREES FOR ONLY THE SECOND DAY IN A ROW. THE CONVECTIVE TEMPERATURE ACROSS THE AREA IS ALSO IN THE UPPER 80S TO LOWER 90S SO SHOWERS AND THUNDERSTORMS ARE LIKELY TO DEVELOP AS WE GO THROUGH THE AFTERNOON. STORMS HAVE ALREADY POPPED ACROSS MUCH OF NEW YORK STATE AND PORTIONS OF NORTHERN NEW ENGLAND. SPC MESOANALYSIS HAS UP TO 3000 J/KG OF SB CAPE ACROSS MUCH OF THE AREA WITH LITTLE TO NO CONVECTIVE INHIBITION. LIKE YESTERDAY... THERE IS VERY LITTLE SHEAR. BETWEEN THIS AND A LACK OF A GOOD TRIGGER LIKE A SHORTWAVE OR A FRONT...EXPECT THE THREATS FROM THESE STORMS TO MAINLY BE HEAVY RAIN AND FREQUENT LIGHTNING. PRECIPITABLE WATER VALUES ARE FORECAST TO INCREASE TO BETWEEN 1.5 AND 2 INCHES WHICH IS 2 TIMES THE NORMAL. THERE IS A LOW PROBABILITY OF STRONG WIND GUSTS TO 50 MPH AND PEA SIZE HAIL WITH ANY OF THESE STORMS. THE HRRR MODEL STILL SHOWS A CONVECTIVE LINE MOVING THROUGH SOUTHERN NEW ENGLAND BETWEEN 21-01Z. FROM JUST THE INSTABILITY AND SHEAR AVAILABLE...WOULD HAVE LOW CONFIDENCE ON THIS LINE DEVELOPING. HOWEVER...THE HRRR IS DOING A GREAT JOB WITH THE CONVECTION ACROSS NEW YORK STATE SO TEND TO HAVE A BIT MORE CONFIDENCE IN THAT MODELS SOLUTION. HIGHEST CONFIDENCE IS ACROSS NORTHERN MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE CLOSER TO A WEAK SHORTWAVE MOVING THROUGH QUEBEC. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT...LINGERING CONVECTION SHOULD DWINDLE DOWN AFTER SUNSET AS DIURNAL HEATING DISSIPATES. EXPECT TEMPS TO DROP INTO THE MID TO UPPER 60S WITH LOW 70S FOR METRO PROVIDENCE AND BOSTON. CHANCES FOR FOG DEVELOPMENT WILL INCREASE AGAIN AS DEWPOINTS ARE HIGH. EXPECT MUCH OF THE REGION TO SEE SOME PATCHY FOG WITH THE CAPE/ISLANDS HAVING THE BEST CHANCE FOR LOCALLY DENSE. WEDNESDAY...ANOTHER ROUND OF HEAT AND CONVECTION WILL OCCUR ON WEDNESDAY. A WEAK SHORTWAVE LOOKS TO MOVE THROUGH THE PATTERN DURING THE AFTERNOON HOURS. CAPE VALUES ARE STILL QUIET HIGH AND WITH THIS TRIGGER ALOFT...EXPECT THUNDERSTORM CHANCES TO BE MORE WIDESPREAD. SHEAR VALUES ARE STRONGER NEARING 25-30KTS AND WITH PWATS AGAIN NEARING 1.5-2 INCHES...HEAVY DOWNPOURS APPEAR TO BE THE MAIN THREATS ALONG WITH GUSTY WINDS AS UPDRAFTS WILL BE ABLE TO MAINTAIN THEMSELVES. TEMPERATURES WILL BE FEEL A LITTLE COOLER WITH TEMPS ONLY REACHING INTO THE MID TO UPPER 80S. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... HEADLINES... * HEAVY RAIN THREAT PREVAILS THROUGHOUT THIS TIMEFRAME * LOCALIZED URBAN AND LOW LYING AREA FLOODING IS A POSSIBILITY * STRONG THUNDERSTORMS POSSIBLE LATE THIS WEEK INTO NEXT MONDAY * CONTINUED WARM AND MUGGY CONDITIONS 25/00Z GUIDANCE CONTINUES TO EXHIBIT OVERALL AGREEMENT WITH THEIR SYNOPTIC SOLUTIONS. THERE REMAIN SOME DETAIL DIFFERENCES...WHICH WILL TAKE SOME TIME TO RESOLVE BASED ON THE NATURE OF THE EXPECTED PATTERN FOR MOST OF THIS WEEK. HAVE LOWER CONFIDENCE IN THE DETAILS OF ANY PARTICULAR SOLUTION AT THIS TIME. AS SUCH...FOLLOWED A CONSENSUS BLEND TO MINIMIZE THE DETAIL DIFFERENCES. IT APPEARS SOUTHERN NEW ENGLAND IS IN FOR A PROLONGED STRETCH OF UNSETTLED WEATHER OVER THE NEXT SEVERAL DAYS. A MID-LEVEL BLOCKING PATTERN IS EXPECTED TO ESTABLISH ITSELF ACROSS THE NORTHERN HALF OF THE CONUS...PLACING OUR REGION JUST EAST OF A MID-LEVEL TROUGH. AT THE SURFACE...THIS WOULD MAINTAIN A GENERAL SOUTHERLY FLOW INTO THIS WEEKEND ALONG WITH HIGH HUMIDITY. TEMPERATURES SHOULD GRADUALLY MODERATE AS CLOUDS BECOME MORE PREVALENT LATE THIS WEEK. AM NOT EXPECTING A COMPLETE WASHOUT...BUT FINDING IT TOUGH TO FIND A DAY WITHOUT A CHANCE OF SHOWERS OR THUNDERSTORMS AT SOME POINT. HIGH HUMIDITY WILL POSE A RISK FOR LOCALIZED HEAVY RAINFALL IN STRONGER SHOWERS AND THUNDERSTORMS INTO EARLY NEXT WEEK. && .AVIATION /17Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH WEDNESDAY NIGHT...MODERATE CONFIDENCE. THROUGH 00Z...MAINLY VFR. AFTER 21Z...PATCHY MVFR/IFR CONDITIONS IN SCT SHRA/TSRA. TONIGHT...MAINLY VFR. SCT SHRA/TSRA CONTINUES TO MOVE EAST THROUGH 06Z RESULTING IN BRIEF MVFR/IFR CONDITIONS. MVFR/IFR STRATUS AND FOG LIKELY ALONG THE SOUTH COAST. WEDNESDAY...ANOTHER ROUND OF SHRA/TSRA IN THE AFTERNOON HOURS. GUSTY WINDS AND REDUCED VSBYS GREATEST THREATS. WEDNESDAY NIGHT...SCT SHRA/TSRA POSSIBLE DURING THE EVENING HOURS. LOW CLOUDS/FOG POSSIBLE AGAIN ALONG THE SOUTH COAST WITH MVFR/IFR CONDITIONS. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. OUTLOOK...THURSDAY THROUGH SATURDAY... THURSDAY...SHRA/TSRA LOOK TO REMAIN CONFINED ACROSS INTERIOR NEW ENGLAND. LOCAL +RA EXPECTED. GUSTY WINDS POSSIBLE. LOW-VFR TO MVFR CIGS WITH CB ALONG WITH MVFR-IFR VSBYS POSSIBLE. PREVAILING S-SW WINDS. LLWS POSSIBLE THU NIGHT MAINLY ACROSS S COASTAL AREAS. FRIDAY AND SATURDAY... SHRA/TSRA WILL BE MORE WIDESPREAD ACROSS MOST OF SOUTHERN NEW ENGLAND...WITH THE BEST CHANCE ACROSS CENTRAL AND WESTERN AREAS. +RA EXPECTED WITH GUSTY WINDS POSSIBLE. LOW-VFR TO MVFR CIGS WITH CB ALONG WITH MVFR-IFR VSBYS POSSIBLE. PREVAILING SW WINDS. LLWS MAY BE POSSIBLE FRI THROUGH SAT ACROSS S COASTAL AREAS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH WEDNESDAY...HIGH CONFIDENCE. TODAY INTO WEDNESDAY... A REPEAT ESSENTIALLY OF YESTERDAY. ANY MORNING FOG WILL BURN OFF BY MIDDAY AND GIVES WAY TO LATE DAY TSTMS. MAIN THREATS HEAVY RAIN AND FREQUENT LIGHTNING. THIS PATTERN WILL REPEAT INTO WEDNESDAY. ONLY CAVEAT IS THAT SCA POTENTIAL INCREASES ON WEDNESDAY AS SEAS ACROSS THE OUTER WATERS MAY REACH 5 FT THANKS TO 15-20 KTS WIND GUSTS. OUTLOOK...THURSDAY THROUGH SATURDAY... SOUTH TO SOUTHWEST WINDS MAY GUST UP TO 25 KT AT TIMES...MAINLY FRIDAY INTO SATURDAY. LONG SOUTH TO SOUTHWEST FETCH WILL BRING SEAS UP TO 5-8 FT ACROSS THE OUTER COASTAL WATERS...POSSIBLY INTO RI AND BLOCK ISLAND SOUNDS AS WELL. SCATTERED SHOWERS/TSTMS... MAINLY DURING THE AFTERNOON/EVENING HOURS. HEAVY RAIN AND FREQUENT LIGHTNING IN ANY STORMS. PATCHY FOG WITH REDUCED VSBYS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...AIR QUALITY ALERT UNTIL 10 PM EDT THIS EVENING FOR MAZ020>024. NH...NONE. RI...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008. MARINE...NONE. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...RLG SHORT TERM...DUNTEN LONG TERM...BELK AVIATION...BELK/RLG MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
334 PM EDT TUE JUN 25 2013 .SYNOPSIS... A BERMUDA HIGH PRESSURE SYSTEM WILL KEEP THE REGION LOCKED IN A HOT AND HUMID AIRMASS THROUGH AT LEAST THURSDAY. A STRONG COLD FRONT WILL APPROACH FROM THE WEST ON THURSDAY AND CROSS THE AREA BY FRIDAY BEFORE STALLING OFF THE COAST. AS A RESULT A PERIOD OF UNSETTLED WEATHER IS EXPECTED FOR THE START OF JULY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... NEITHER OF THE MODELS 500MB ANALYSIS LOOKED SPOT ON IN THE MIDWEST AS THE SERIES OF CONVECTIVE COMPLEXES CONTINUE TO CAUSE INITIALIZATION ISSUES. IF ANYTHING THE SYSTEMS LOOK SLIGHTLY SLOWER THAN MODELED. THERMALLY A GFS AND WRF-NMMB COMPROMISE WORK THE BEST. BUT THEY DIVERGE RATHER QUICKLY AFTER THAT. INTO THIS EVENING SCATTERED THUNDERSTORMS WILL CONTINUE TO MOVE THROUGH OUR CWA. IN GENERAL THE THERMODYNAMIC AND KINEMATIC ENVIRONMENT IS NOT ON THE LEVEL OF YESTERDAY. SO FAR THE ORIENTATION HAS BEEN MORE NORTH THAN SOUTH AND HIEST POPS WERE KEPT THERE. WHILE ONE OR TWO PULSY TYPE STORMS MIGHT REQUIRE WARNINGS THE OVERALL WEAK FCST BULK SHEAR ALONG WITH POORER MID LEVEL LAPSE RATES SHOULD KEEP THIS BELOW LEVELS OF YESTERDAY`S CONVECTION. SOME OF THE 12Z MESOSCALE MODELS (SPC WRF/NMM) WENT TOO MUCH THE OTHER WAY AND SHOWING WAY TOO LITTLE. BEST FIT IS BETWEEN THE RAP AND SLIGHTLY TONED DOWN HR3. FARTHER UPSTREAM MORE CONVECTION IS FORECAST TO DEVELOP OVER THE UPPER OHIO VALLEY. THIS ONE WILL HAVE SOME SHORT WAVE SUPPORT, BUT GIVEN ITS ARRIVAL LATER IN THIS EVENING LOWERS CONFIDENCE LEVELS AS TO SUSTAINABILITY. WE DID CARRY POPS THROUGH THE EVENING AND WE WILL SEE HOW THE PRESENT DEVELOPMENT EVOLVES. STAT GUIDANCE HAS BEEN PRETTY REASONABLE WITH MINS AND WE CONTINUE TO FOLLOW A MET/MAV BLEND. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... WE WILL ISSUE A HEAT ADVISORY FOR URBAN AREAS FOR WEDNESDAY. CONFIDENCE IS NOT THE GREATEST, BUT THIS WILL BE THE THIRD STRAIGHT DAY OF 90 PLUS HEAT AND NOT SURE IF WE ARE GOING TO GET AS MUCH COOLING FROM TSRAS TONIGHT AS LAST NIGHT. NAM MOS IS RUNNING APPROXIMATELY 3-6F TOO LOW ON HOURLY TEMPS TODAY, SO GUIDANCE WAS NOT USED ON WEDNESDAY. GFS MOS WHICH HAS VERIFIED BETTER MATCHES PRETTY CLOSELY WITH FCST 850/925MB TEMPS AS WELL AS 1000-850 THICKNESSES. OF CONCERN ALSO HAS BEEN THAT STAT GUIDANCE HAS BEEN MIXING DEW POINTS DOWNWARD TOO QUICKLY THE PAST TWO DAYS. WHETHER ITS THE LEE SIDE TROF OR JUST HOW WET THIS JUNE HAS BEEN, NOT BANKING ON THE THIRD TIME BEING THE CHARM. RIGHT NOW THIS APPEARS TO BE ONE DAY EVENT REASON FOR ADVY VS WARNING. SENSIBLE WEATHER, IF TODAY IS THE RELATIVE LULL IN CONVECTIVE ACTIVITY, WEDNESDAY IS SHOWING A TICK UP. NEARLY ALL KINEMATIC AND THERMODYNAMICALLY FORCINGS ARE SLIGHTLY STRONGER THAN TODAY. THE ONE PROBLEM WE ARE SEEING WITH WEDNESDAY IS THE SPLIT BETWEEN THE BETTER FORCING NORTHWEST AND THE GREAT INSTABILITY AND FCST MID LEVEL LAPSE RATES SE. PLUS THE FACT THE MODELS MAY BE FAST WITH THE OVERALL PROGRESSION WILL HAVE US KEEP POPS AS CHANCE. SPC SLIGHT RISK NORTHWEST HALF OF OUR CWA IS A GOOD FIT AS THAT IS CLOSER PROXIMITY TO FORCING WHICH SHOULD BE PLACE FOR A BETTER CHANCE OF ORGANIZATIONAL LINE OR CLUSTER. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... THE WARM AND STICK AMS WILL REMAIN IN PLACE WED NIGHT AND BY THU A STRONG S/WV, AND LOW PRESSURE SYS WILL APPROACH FROM THE W. THE CDFNT ASSOCD WITH THIS LOW WILL CROSS THE REGION BY FRI MRNG. WITH DEW POINTS INCREASING ON THU IT WILL REMAIN VERY UNCOMFORTABLE DESPITE MORE CLOUDS AND TEMPS A FEW DEGREES LOWER THAN ON WED. WITH A DECENTLY ROBUST LOW (FOR LATE JUNE) AND CDFNT APPROACHING, THU COULD BE THE BEST SHOT OF SHWRS AND TSTMS FOR THE WEEK. SPC HAS ALREADY PLACED A GOOD PORTION OF THE AREA GENLY WEST OF PHILADELPHIA IN A SLGT RISK. THE CDFNT WILL CROSS THE REGION BY FRIDAY BUT REMAIN CLOSE OFFSHORE. PRECIP CHCS WILL DECREASE AND FRIDAY COULD END UP BEING DRY OR MOSTLY DRY. SWLY FLOW WILL THEN PREVAIL THRU THE WEEKEND INTO NEXT WEEK AND THE FLOW WILL STRENGTHEN ANS THE TROF DEEPENS TO THE W. THIS WILL KEEP UNSETTLED WX OVER THE AREA WITH CHCS OF SHWRS AND TSTMS EACH DAY. THERE ARE NO SIGNIFICANT SYNOPTIC FEATURE OF NOTE, BUT EACH DAY`S TSTM CHCS WILL BE PARTIALLY BASED ON BOUNDARIES AND ANY S/WVS THAT MAY BE PASSING THRU THE FLOW, WHICH EACH MDL WILL HANDLE DIFFERENTLY AND ARE DIFFICULT TO DIAGNOSE AT THIS TIME SCALE. FOR NOW, WILL MAINTAIN LOW CHC POPS. MON LOOKS LIKE THERE COULD BE A WK LOW SO WILL GO A TAD HIGHER THERE, BUT CONFIDENCE REMAINS LOW ON PRECIP CHCS AND LOCATION IN THE EXTENDD PD. AFTER THU, TEMPS LOOK TO RETURN CLOSER TO NRML, BUT WILL LIKELY REMAIN SLIGHTLY ABV THRU THE PD. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 18Z TAFS ARE CARRYING A TEMPO GROUP FOR THUNDERSTORMS THIS AFTERNOON WITH MVFR CONDITIONS FROM THE KPHL METRO AREA AIRPORTS NORTHWARD. OTHERWISE PREVAILING VFR CONDITIONS EXPECTED THROUGH THIS EVENING WITH POSSIBLY MVFR CONDITIONS LATE TONIGHT. THEN WE START ALL OVER AGAIN ON WEDNESDAY. THIS AFTERNOON BEST FORCING AND WHERE ONGOING CONVECTION IS BOTH FAVOR THUNDERSTORMS AT NORTHERN AIRPORTS AND TERMINALS. CONFIDENCE IS LESS TOWARD THE KPHL METRO AIRPORTS WHERE THEY SHOULD BE MORE ISOLATED. CONFIDENCE WAS TOO LOW AT KACY AND KMIV TO INCLUDE IN TAFS. OUTSIDE OF THAT, VFR CONDITIONS ARE FORECAST WITH WEST TO SOUTHWEST WINDS AVERAGING AROUND 10 KT. SEA BREEZE FRONT SHOULD NOT MAKE MUCH MOVEMENT OFF THE COAST. WE ARE NOT FORECASTING IT TO REACH KACY. THIS EVENING ORGANIZED THUNDERSTORMS DEVELOPING IN THE OHIO VALLEY ARE NOT FORECAST TO REACH THE TERMINALS. LOWEST CONFIDENCE KRDG. WE SHOULD JUST HAVE SOME OUTFLOW VFR MID AND HIGH LEVEL CLOUDS. SOUTHWEST WINDS AVERAGING 5 TO 10 KTS. OVERNIGHT WE CARRIED SOME MVFR CONDITIONS LATE AT THE FOGGIER MORE OUTLYING TERMINALS. THIS MIGHT NEED SOME ADJUSTMENT BASED ON ANY CONVECTION DIRECTLY AFFECTING THE AIRPORTS. WINDS SHOULD BE LIGHT. A VFR MORNING IS FORECAST FOR ALL OF THE TERMINALS WITH CU BASED CLOUDS DEVELOPING. WEST TO SOUTHWEST WINDS SHOULD INCREASE TO AROUND 10 KTS AGAIN. THE SEA BREEZE FRONT WILL STRUGGLE TO GET OFF THE COAST AGAIN, MAYBE EVEN MORE SO THAN TODAY. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE FORECAST FOR LATER WEDNESDAY, SO WE INCLUDED A PROB30 FOR KPHL AS A START. OUTLOOK... WED NIGHT INTO THU MORNING...MOSTLY VFR WITH SHORT PERIODS OF SUB-VFR IN MORNING FOG AND/OR SCT SHOWERS/TSTMS. MD CONFIDENCE. THU AFTERNOON THROUGH SAT...GENLY VFR. HOWEVER, THERE WILL BE PERIODS OF MVFR/IFR (POSSIBLY PROLONGED ONES) IN MORNING LOW CLOUDS AND FOG AND AREAS OF SHOWERS AND TSTMS. LOW CONFIDENCE. && .MARINE... THE RETURN FLOW BEHIND THE DEPARTING BERMUDA HIGH WILL KEEP A W/SW WIND ACROSS THE WATERS TODAY AND TONIGHT. WINDS/SEAS WILL REMAIN BELOW SCA CONDITIONS THRU THE PERIOD. FAIR WEATHER EXPECTED THIS MORNING...FOLLOWED BY SCT SHOWERS/TSTMS THIS AFTERNOON AND EARLY EVENING. FAIR WEATHER WILL RESUME LATER TONIGHT INTO WED MORNING. SEAS ON THE OCEAN WILL BE AROUND 2-4 FT AND 1-2 FT OVER DEL BAY. REMEMBER...WINDS AND WAVES WILL BE LOCALLY HIGHER IN TSTMS. OUTLOOK... SUB-SCA CONDITIONS ARE EXPECTED INTO THURSDAY MORNING. AFTER THAT INCREASING SWLY FLOW MIGHT BRING SCA CRITERIA MAINLY FOR SEAS, MORE SO THAN WINDS, TO THE OCEAN WATERS BEGINNING LATER THU AND PSBLY CONTINUING INTO THE WKND. RIGHT NOW CONFIDENCE REMAINS LOWER THAN AVERAGE THAT THIS WILL OCCUR AS WAVE WATCH GUIDANCE OFTEN IS TOO BULLISH UNDER THESE REGIMES. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...HEAT ADVISORY FROM 11 AM TO 8 PM EDT WEDNESDAY FOR PAZ070-071- 102-104-106. NJ...HEAT ADVISORY FROM 11 AM TO 8 PM EDT WEDNESDAY FOR NJZ015- 017>019. DE...HEAT ADVISORY FROM 11 AM TO 8 PM EDT WEDNESDAY FOR DEZ001. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...NIERENBERG NEAR TERM...GIGI SHORT TERM...GIGI LONG TERM...NIERENBERG AVIATION...GIGI/NIERENBERG MARINE...GIGI/NIERENBERG
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
115 PM EDT TUE JUN 25 2013 .SYNOPSIS... BERMUDA RIDGE KEEPS THE REGION LOCKED IN A HOT AND HUMID AIRMASS THROUGH AT LEAST THE END OF THE WORK WEEK. A STRONG COLD FRONT WILL NEAR FROM THE NORTHWEST ON THURSDAY BUT BEGIN TO SLOW UPON ITS ARRIVAL. THE FRONT SHOULD LIMP THROUGH BY FRIDAY BUT THEN STALL TO OUR IMMEDIATE EAST THROUGH EARLY NEXT WEEK KEEPING A PROLONGED PERIOD OF UNSETTLED WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12Z UA ANALYSIS SHOWS A MUCH LESS DYNAMIC SET-UP IN OUR CWA FROM YDA AS UPSTREAM 700 AND 500 MB TEMPS ARE 2 TO 4C WARMER AND GONE IS THE STGR DPVA AND 50-60KT JET STREAK FROM YDA. 12Z WRF-NMMB KEEPS DECENT FORECAST BULK SHEAR NORTH OF OUR CWA AND FCST MID LEVEL LAPSE RATES ARE ABOUT 1C/KM LESS THAN YESTERDAY. OVERALL THINK THAT THE LATEST HR3 AND RAP HAVE A BETTER HANDLE ON THE EVOLUTION FOR THIS AFTERNOON INTO THIS EVENING THAN THE MORE CHARGED 00Z HI RES NMM AND ARW DO. NOTWITHSTANDING ABOVE AND I HAVE BEEN WRONG BEFORE AND WILL BE WRONG AGAIN (MAYBE BY 4 PM OR EVEN EARLIER), WILL HAVE TO SEE HOW CONVECTION FAR NORTH EVOLVES FROM NWRN PA AS ITS THE CLOSEST TO THE BEST FCST BULK SHEAR. WE ADJUSTED POP ORIENTATION HIGHEST NNW AND LOWEST SSE IN OUR CWA. 12Z UA ANLYS SUGGESTING NO FURTHER ADJUSTMENT TO MAX TEMPS NEEDED. SURPRISED HOW DEW POINTS ONCE AGAIN STRUGGLING TO DROP IN SPITE OF DRIER AIR AGAIN JUST ABOVE THE BOUNDARY LAYER. NUDGED THEM UPWARD AND MAX HEAT INDICES ARE CURRENTLY IN THE MID 90S. THE CURRENT RIDGING IS KEEPING THE AREA DRY THIS MORNING...BUT THEN THE DAYTIME HEATING AND THE LINGERING HUMIDITY ALONG WITH A WEAK SHORTWAVE MOVING THRU...WILL CREATE MORE SCT SHOWERS/TSTMS THIS AFTERNOON. THE COVERAGE OF THE ACTIVITY WILL NOT BE AS MUCH AS YESTERDAY...BUT THERE WILL BE ENOUGH TO KEEP THE CHC POPS IN THE FCST. THE UPPER WINDS WILL INCREASE SOMEWHAT THIS AFTERNOON...SO THE STORMS WILL HAVE A GREATER FORWARD (ERLY) MOTION. TEMPERATURES WILL ONCE AGAIN REACH THE UPPER 80S TO LOW 90S ACROSS THE AREA. THIS WILL BE DAY2 OF OUR LATEST (EXPECTED) HEAT WAVE. DEW POINT READINGS WILL PROBABLY BE A BIT LESS THAN YDAY WITH A MORE WRLY FLOW ALOFT. WE DO NOT EXPECT THAT THE APPARENT TEMPS WILL BE GREAT ENOUGH FOR ANY HEAT RELATED HEADLINES TODAY...BUT CARE SHOULD STILL BE EXERCISED FOR THOSE WHO WILL BE OUTDOORS TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... ANY LINGERING SHOWER/TSTM ACTIVITY WILL DIMINISH THIS EVENING AND ANOTHER MILD/HUMID...BUT DRY FCST IS EXPECTED. LOWS WILL ONLY DROP INTO THE LOW 70S ACROSS THE METRO AREAS AND THE DELMARVA...WHILE UPPER 60S WILL BE FOUND ACROSS NRN NJ. PATCHY FOG IS POSSIBLE ... ESPECIALLY IN AREAS THAT RECEIVE SHOWERS TODAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... 5-WAVE MODEL GUIDANCE IS SHOWING A RATHER ROBUST BLOCKING PATTERN DEVELOPING ACROSS THE REGION. A LARGE RIDGE WILL PUSH INTO THE SOUTHWEST UNITED STATES WHILE THE RIDGING DOWNSTREAM OF OUR REGION AMPLIFIES ACROSS THE WESTERN ATLANTIC. THIS PLACES US IN A DEEPENING EAST COAST TROUGH THAT LOOKS TO DEEPEN WITH TIME. THIS WILL ALSO SLOW THE PROGRESSION OF ANY WEST-EAST MOVING SYSTEMS AND EFFECTIVELY KEEP US UNSETTLED HEADING INTO THE FIRST WEEK OF JULY. BEFORE THE BLOCKING GETS FULLY SETUP WE CONTINUE WITH A RATHER PROGRESSIVE PSEUDO-ZONAL FLOW ALOFT. THE JET STREAM STILL REMAINS LOCKED FAR TO OUR NORTH ALLOWING THE HEAT AND HUMIDITY TO CONTINUE FOR THE FIRST PART OF THE LONGTERM. THIS WILL PROVIDE THE CONTINUED ONSLAUGHT OF DIURNALLY DRIVEN CONVECTION ACROSS THE AREA WEDNESDAY AND THURSDAY. ON WEDNESDAY THE SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD WITHOUT MUCH UPPER LEVEL SUPPORT SO ORGANIZATION DOES NOT SEEM TO BE AN ISSUE THOUGH LOCALLY STRONG WIND GUSTS WITH VERY HEAVY RAIN CAN NOT BE RULED OUT. 850MB TEMPERATURES JUMP CLOSE TO 20C BUT STILL THINK THAT CLOUD COVER WILL PLAGUE THE REGION EARLIER ON WEDNESDAY THAN IN DAYS PAST. THERE COULD EVEN BE ON-GOING CONVECTION THROUGH THE MORNING HOURS TO HELP HAMPER HIGHS REACHING THE MID-90S. PLAYED IT A BIT MORE CONSERVATIVE AND WENT LOW-90S ACROSS THE METRO AREA WITH WARMER TEMPERATURES OVER THE WEST AS DOWNSLOPING SHOULD HELP TO WARM THEM A COUPLE MORE DEGREES. HEADING INTO THURSDAY WE START TO SEE THE ZONAL FLOW BREAK DOWN AS A MID-LEVEL IMPULSE DROPS ACROSS THE JET AND DRAGS TO INTO THE MID-WEST. THIS WILL ALLOW FOR VERY DEEP SOUTHWESTERLY FLOW TO SETUP ACROSS THE AREA AND WILL PUMP IN EVEN MORE MOISTURE. DECENT CYCLONIC FLOW ALOFT WILL INCREASE DURING THE DAY AS HEIGHTS BEGIN TO FALL AHEAD OF THE APPROACHING IMPULSE. THURSDAY IS SETTING UP TO BE AN ACTIVE DAY ACROSS THE REGION IN TERMS OF SEVERE WEATHER. SPC HAS PUT THE WESTERN PORTIONS OF THE CWA IN A SLIGHT RISK GIVEN THE AMOUNT OF SURFACE BASED INSTABILITY THAT WILL BE PRESENT AND BETTER UPPER LEVEL SUPPORT ALLOWING FOR MORE ORGANIZED CLUSTER OF STORMS. THURSDAY COULD ALSO BE THE LAST DAY OF 90+F WE SEE THIS WEEK, BUT THIS GREATLY DEPENDS ON THE AMOUNT OF CLOUD COVER AND THE TIMING OF THE CONVECTION. FRIDAY STILL LOOKS TO PROVIDE ANOTHER ROUND FOR SEVERE WEATHER AS THE COLD FRONT, TIED TO AN ADVANCING SURFACE LOW OVER THE GREAT LAKES, NEARS FROM THE NORTHWEST. THERE SHOULD STILL BE PLENTY OF INSTABILITY LEFT OVER FROM THURSDAY TO ALLOW FOR SURFACE BASED INITIATION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS WITH A FEW BREAKS IN THE OVERALL CLOUD COVER. TEMPERATURES WILL BE A FEW DEGREES COOLER ON FRIDAY THAN THURSDAY SO WE SHOULD BE ABLE TO BREAK THE CURRENT HEAT WAVE BY THEN. THE MID-LEVEL LOW SHOULD RETROGRADE A BIT DURING THE AFTERNOON HOURS ON FRIDAY SO WE LOSE A BIT OF THE COLD POOL INTERACTION BUT WE ALSO GAIN A MORE NEGATIVELY TILTED SHORTWAVE. THIS SETUP MAY MIMIC WHAT OCCURRED LATE LAST WEEK WHERE CONVECTION BEGAN LATE MORNING AND THEN FORMED INTO A LARGE BLOB OF SLOW MOVING HEAVY SHOWERS CAUSING FLASH FLOODING. GRANTED THERE IS THE LINEAR LIFTING ALONG THE COLD FRONT BUT IT REALLY DOES NOT FLY THROUGH THE REGION AND JUST SLOWLY LIMPS THROUGH. HEADING INTO THE WEEKEND WE KEEP THE MID-LEVEL TROUGH ENTRENCHED OVER THE REGION WITH PRETTY GOOD UPPER LEVEL DYNAMICS AS MULTIPLE WAVES RIDE UP THE EASTERN SEABOARD. THE UPPER JET WILL ALSO BE IN A GOOD SPOT WITH US IN ITS RIGHT ENTRANCE REGION FOR A PROLONGED TIME PERIOD. PWATS WILL STILL REMAIN VERY LARGE AND THUS WE CONTINUE TO RUN THE RISK FOR VERY HEAVY DOWNPOURS THROUGH AT LEAST EARLY NEXT WEEK. TEMPERATURES WILL BE MORE ON THE SEASONAL SIDE FROM FRIDAY ONWARD. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 18Z TAFS WILL CARRY A TEMPO GROUP FOR THUNDERSTORMS THIS AFTERNOON WITH MVFR CONDITIONS FROM THE KPHL METRO AREA AIRPORTS NORTHWARD. OTHERWISE PREVAILING VFR CONDITIONS EXPECTED THROUGH THIS EVENING WITH POSSIBLY MVFR CONDITIONS LATE TONIGHT. THEN WE START ALL OVER AGAIN ON WEDNESDAY. THIS AFTERNOON BEST FORCING AND WHERE ONGOING CONVECTION IS BOTH FAVOR THUNDERSTORMS AT NORTHERN AIRPORTS AND TERMINALS. CONFIDENCE IS LESS TOWARD THE KPHL METRO AIRPORTS WHERE THEY SHOULD BE MORE ISOLATED. CONFIDENCE WAS TOO LOW AT KACY AND KMIV TO INCLUDE IN TAFS. OUTSIDE OF THAT, VFR CONDITIONS ARE FORECAST WITH WEST TO SOUTHWEST WINDS AVERAGING AROUND 10 KT. SEA BREEZE FRONT SHOULD NOT MAKE MUCH MOVEMENT OFF THE COAST. WE ARE NOT FORECASTING IT TO REACH KACY. THIS EVENING ORGANIZED THUNDERSTORMS DEVELOPING IN THE OHIO VALLEY ARE NOT FORECAST TO REACH THE TERMINALS. LOWEST CONFIDENCE KRDG. WE SHOULD JUST HAVE SOME OUTFLOW VFR MID AND HIGH LEVEL CLOUDS. SOUTHWEST WINDS AVERAGING 5 TO 10 KTS. OVERNIGHT WE CARRIED SOME MVFR CONDITIONS LATE AT THE FOGGIER MORE OUTLYING TERMINALS. THIS MIGHT NEED SOME ADJUSTMENT BASED ON ANY CONVECTION DIRECTLY AFFECTING THE AIRPORTS. WINDS SHOULD BE LIGHT. A VFR MORNING IS FORECAST FOR ALL OF THE TERMINALS WITH CU BASED CLOUDS DEVELOPING. WEST TO SOUTHWEST WINDS SHOULD INCREASE TO AROUND 10 KTS AGAIN. THE SEA BREEZE FRONT WILL STRUGGLE TO GET OFF THE COAST AGAIN, MAYBE EVEN MORE SO THAN TODAY. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE FORECAST FOR LATER WEDNESDAY, SO WE INCLUDED A PROB30 FOR KPHL AS A START. OUTLOOK... WEDNESDAY NIGHT INTO THURSDAY MORNING...MOSTLY VFR WITH SHORT PERIODS OF SUB-VFR IN MORNING FOG AND/OR SCT SHOWERS/TSTMS. THURSDAY AFTERNOON THROUGH SATURDAY...MORE MVFR AND IFR CONDITIONS IN MORE NUMEROUS SHOWERS/TSTMS AS WELL AS MORNING LOW CLOUDS AND FOG. && .MARINE... THE RETURN FLOW BEHIND THE DEPARTING BERMUDA HIGH WILL KEEP A W/SW WIND ACROSS THE WATERS TODAY AND TONIGHT. WINDS/SEAS WILL REMAIN BELOW SCA CONDITIONS THRU THE PERIOD. FAIR WEATHER EXPECTED THIS MORNING...FOLLOWED BY SCT SHOWERS/TSTMS THIS AFTERNOON AND EARLY EVENING. FAIR WEATHER WILL RESUME LATER TONIGHT INTO WED MORNING. SEAS ON THE OCEAN WILL BE AROUND 2-4 FT AND 1-2 FT OVER DEL BAY. REMEMBER...WINDS AND WAVES WILL BE LOCALLY HIGHER IN TSTMS. OUTLOOK... SUB-SCA CONDITIONS ARE EXPECTED INTO THURSDAY MORNING. AFTER THAT THE FORECAST INCREASING SOUTHERLY FLOW MIGHT BRING SCA CRITERIA BASED ON SWELLS, MORE SO THAN WINDS, TO THE OCEAN WATERS LATER THURSDAY THROUGH FRIDAY. CONFIDENCE RIGHT NOW REMAINS LOWER THAN AVERAGE THAT THIS WILL OCCUR AS WAVE WATCH GUIDANCE OFTEN IS TOO BULLISH UNDER THESE REGIMES. && .CLIMATE... WE STAND A PRETTY GOOD CHANCE OF HAVING THE WETTEST JUNE ON RECORD IN PHILADELPHIA. WE LOOKED BACK AT THE 10 PREVIOUS WETTEST JUNES ON RECORD AND SAW HOW THE REST OF THE METEOROLOGICAL SUMMER WENT FORWARD. WET BEGETTED(SP) MORE WET. GIVEN HOW WET THE GFS AND ECMWF LOOK INTO THE START OF JULY THAT NOTION IS HOLDING. BOTH ENSUING MONTHS AVERAGED WETTER THAN THE CURRENT NORMALS WITH EIGHT OF THE TEN MONTHS COMBINED AVERAGING WETTER THAN NORMAL. ALL OF THE MONTHS HAD TWO INCHES OR MORE OF RAINFALL. AS FAR AS TEMPERATURES WENT, JULY AVERAGED SLIGHTLY LOWER THAN THE CURRENT NORMAL, WHILE AUGUST WAS VERY CLOSE TO THE CURRENT NORMAL. SIX OF THE TEN AUGUSTS WERE AS WARM OR WARMER THAN JULY. YEAR JULY AVG JULY AUG AVG AUGUST TEMP PCPN TEMP PCPN 1887 80.7 7.14 74.0 2.31 1906 75.6 5.33 76.2 9.56 1928 77.3 3.60 77.2 5.47 1938 77.3 6.52 78.3 4.10 1962 72.0 2.30 72.0 6.58 1969 75.1 8.33 75.2 2.66 1973 77.9 2.39 78.7 2.03 1975 76.6 6.32 77.0 2.11 2003 78.7 2.01 78.2 3.26 2006 79.4 4.27 78.1 3.93 AVG 77.1 4.82 76.5 4.20 1981-2010 NML 78.1 4.35 76.6 3.50 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...HEAVENER NEAR TERM...GIGI/O`HARA SHORT TERM...O`HARA LONG TERM...HEAVENER AVIATION...GIGI/O`HARA MARINE...O`HARA CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1118 AM EDT TUE JUN 25 2013 .SYNOPSIS... BERMUDA RIDGE KEEPS THE REGION LOCKED IN A HOT AND HUMID AIRMASS THROUGH AT LEAST THE END OF THE WORK WEEK. A STRONG COLD FRONT WILL NEAR FROM THE NORTHWEST ON THURSDAY BUT BEGIN TO SLOW UPON ITS ARRIVAL. THE FRONT SHOULD LIMP THROUGH BY FRIDAY BUT THEN STALL TO OUR IMMEDIATE EAST THROUGH EARLY NEXT WEEK KEEPING A PROLONGED PERIOD OF UNSETTLED WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12Z UA ANALYSIS SHOWS A MUCH LESS DYNAMIC SET-UP IN OUR CWA FROM YDA AS UPSTREAM 700 AND 500 MB TEMPS ARE 2 TO 4C WARMER AND GONE IS THE STGR DPVA AND 50-60KT JET STREAK FROM YDA. 12Z WRF-NMMB KEEPS DECENT FORECAST BULK SHEAR NORTH OF OUR CWA AND FCST MID LEVEL LAPSE RATES ARE ABOUT 1C/KM LESS THAN YESTERDAY. OVERALL THINK THAT THE LATEST HR3 AND RAP HAVE A BETTER HANDLE ON THE EVOLUTION FOR THIS AFTERNOON INTO THIS EVENING THAN THE MORE CHARGED 00Z HI RES NMM AND ARW DO. NOTWITHSTANDING ABOVE AND I HAVE BEEN WRONG BEFORE AND WILL BE WRONG AGAIN (MAYBE BY 4 PM OR EVEN EARLIER), WILL HAVE TO SEE HOW CONVECTION FAR NORTH EVOLVES FROM NWRN PA AS ITS THE CLOSEST TO THE BEST FCST BULK SHEAR. WE ADJUSTED POP ORIENTATION HIGHEST NNW AND LOWEST SSE IN OUR CWA. 12Z UA ANLYS SUGGESTING NO FURTHER ADJUSTMENT TO MAX TEMPS NEEDED. SURPRISED HOW DEW POINTS ONCE AGAIN STRUGGLING TO DROP IN SPITE OF DRIER AIR AGAIN JUST ABOVE THE BOUNDARY LAYER. NUDGED THEM UPWARD AND MAX HEAT INDICES ARE CURRENTLY IN THE MID 90S. THE CURRENT RIDGING IS KEEPING THE AREA DRY THIS MORNING...BUT THEN THE DAYTIME HEATING AND THE LINGERING HUMIDITY ALONG WITH A WEAK SHORTWAVE MOVING THRU...WILL CREATE MORE SCT SHOWERS/TSTMS THIS AFTERNOON. THE COVERAGE OF THE ACTIVITY WILL NOT BE AS MUCH AS YESTERDAY...BUT THERE WILL BE ENOUGH TO KEEP THE CHC POPS IN THE FCST. THE UPPER WINDS WILL INCREASE SOMEWHAT THIS AFTERNOON...SO THE STORMS WILL HAVE A GREATER FORWARD (ERLY) MOTION. TEMPERATURES WILL ONCE AGAIN REACH THE UPPER 80S TO LOW 90S ACROSS THE AREA. THIS WILL BE DAY2 OF OUR LATEST (EXPECTED) HEAT WAVE. DEW POINT READINGS WILL PROBABLY BE A BIT LESS THAN YDAY WITH A MORE WRLY FLOW ALOFT. WE DO NOT EXPECT THAT THE APPARENT TEMPS WILL BE GREAT ENOUGH FOR ANY HEAT RELATED HEADLINES TODAY...BUT CARE SHOULD STILL BE EXERCISED FOR THOSE WHO WILL BE OUTDOORS TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... ANY LINGERING SHOWER/TSTM ACTIVITY WILL DIMINISH THIS EVENING AND ANOTHER MILD/HUMID...BUT DRY FCST IS EXPECTED. LOWS WILL ONLY DROP INTO THE LOW 70S ACROSS THE METRO AREAS AND THE DELMARVA...WHILE UPPER 60S WILL BE FOUND ACROSS NRN NJ. PATCHY FOG IS POSSIBLE ... ESPECIALLY IN AREAS THAT RECEIVE SHOWERS TODAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... 5-WAVE MODEL GUIDANCE IS SHOWING A RATHER ROBUST BLOCKING PATTERN DEVELOPING ACROSS THE REGION. A LARGE RIDGE WILL PUSH INTO THE SOUTHWEST UNITED STATES WHILE THE RIDGING DOWNSTREAM OF OUR REGION AMPLIFIES ACROSS THE WESTERN ATLANTIC. THIS PLACES US IN A DEEPENING EAST COAST TROUGH THAT LOOKS TO DEEPEN WITH TIME. THIS WILL ALSO SLOW THE PROGRESSION OF ANY WEST-EAST MOVING SYSTEMS AND EFFECTIVELY KEEP US UNSETTLED HEADING INTO THE FIRST WEEK OF JULY. BEFORE THE BLOCKING GETS FULLY SETUP WE CONTINUE WITH A RATHER PROGRESSIVE PSEUDO-ZONAL FLOW ALOFT. THE JET STREAM STILL REMAINS LOCKED FAR TO OUR NORTH ALLOWING THE HEAT AND HUMIDITY TO CONTINUE FOR THE FIRST PART OF THE LONGTERM. THIS WILL PROVIDE THE CONTINUED ONSLAUGHT OF DIURNALLY DRIVEN CONVECTION ACROSS THE AREA WEDNESDAY AND THURSDAY. ON WEDNESDAY THE SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD WITHOUT MUCH UPPER LEVEL SUPPORT SO ORGANIZATION DOES NOT SEEM TO BE AN ISSUE THOUGH LOCALLY STRONG WIND GUSTS WITH VERY HEAVY RAIN CAN NOT BE RULED OUT. 850MB TEMPERATURES JUMP CLOSE TO 20C BUT STILL THINK THAT CLOUD COVER WILL PLAGUE THE REGION EARLIER ON WEDNESDAY THAN IN DAYS PAST. THERE COULD EVEN BE ON-GOING CONVECTION THROUGH THE MORNING HOURS TO HELP HAMPER HIGHS REACHING THE MID-90S. PLAYED IT A BIT MORE CONSERVATIVE AND WENT LOW-90S ACROSS THE METRO AREA WITH WARMER TEMPERATURES OVER THE WEST AS DOWNSLOPING SHOULD HELP TO WARM THEM A COUPLE MORE DEGREES. HEADING INTO THURSDAY WE START TO SEE THE ZONAL FLOW BREAK DOWN AS A MID-LEVEL IMPULSE DROPS ACROSS THE JET AND DRAGS TO INTO THE MID-WEST. THIS WILL ALLOW FOR VERY DEEP SOUTHWESTERLY FLOW TO SETUP ACROSS THE AREA AND WILL PUMP IN EVEN MORE MOISTURE. DECENT CYCLONIC FLOW ALOFT WILL INCREASE DURING THE DAY AS HEIGHTS BEGIN TO FALL AHEAD OF THE APPROACHING IMPULSE. THURSDAY IS SETTING UP TO BE AN ACTIVE DAY ACROSS THE REGION IN TERMS OF SEVERE WEATHER. SPC HAS PUT THE WESTERN PORTIONS OF THE CWA IN A SLIGHT RISK GIVEN THE AMOUNT OF SURFACE BASED INSTABILITY THAT WILL BE PRESENT AND BETTER UPPER LEVEL SUPPORT ALLOWING FOR MORE ORGANIZED CLUSTER OF STORMS. THURSDAY COULD ALSO BE THE LAST DAY OF 90+F WE SEE THIS WEEK, BUT THIS GREATLY DEPENDS ON THE AMOUNT OF CLOUD COVER AND THE TIMING OF THE CONVECTION. FRIDAY STILL LOOKS TO PROVIDE ANOTHER ROUND FOR SEVERE WEATHER AS THE COLD FRONT, TIED TO AN ADVANCING SURFACE LOW OVER THE GREAT LAKES, NEARS FROM THE NORTHWEST. THERE SHOULD STILL BE PLENTY OF INSTABILITY LEFT OVER FROM THURSDAY TO ALLOW FOR SURFACE BASED INITIATION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS WITH A FEW BREAKS IN THE OVERALL CLOUD COVER. TEMPERATURES WILL BE A FEW DEGREES COOLER ON FRIDAY THAN THURSDAY SO WE SHOULD BE ABLE TO BREAK THE CURRENT HEAT WAVE BY THEN. THE MID-LEVEL LOW SHOULD RETROGRADE A BIT DURING THE AFTERNOON HOURS ON FRIDAY SO WE LOSE A BIT OF THE COLD POOL INTERACTION BUT WE ALSO GAIN A MORE NEGATIVELY TILTED SHORTWAVE. THIS SETUP MAY MIMIC WHAT OCCURRED LATE LAST WEEK WHERE CONVECTION BEGAN LATE MORNING AND THEN FORMED INTO A LARGE BLOB OF SLOW MOVING HEAVY SHOWERS CAUSING FLASH FLOODING. GRANTED THERE IS THE LINEAR LIFTING ALONG THE COLD FRONT BUT IT REALLY DOES NOT FLY THROUGH THE REGION AND JUST SLOWLY LIMPS THROUGH. HEADING INTO THE WEEKEND WE KEEP THE MID-LEVEL TROUGH ENTRENCHED OVER THE REGION WITH PRETTY GOOD UPPER LEVEL DYNAMICS AS MULTIPLE WAVES RIDE UP THE EASTERN SEABOARD. THE UPPER JET WILL ALSO BE IN A GOOD SPOT WITH US IN ITS RIGHT ENTRANCE REGION FOR A PROLONGED TIME PERIOD. PWATS WILL STILL REMAIN VERY LARGE AND THUS WE CONTINUE TO RUN THE RISK FOR VERY HEAVY DOWNPOURS THROUGH AT LEAST EARLY NEXT WEEK. TEMPERATURES WILL BE MORE ON THE SEASONAL SIDE FROM FRIDAY ONWARD. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. AFTER SUNRISE SKIES WILL BE MOSTLY CLR WITH LIGHT W/SW WINDS EXPECTED. DURING THE AFTERNOON...CU WILL DEVELOP ACROSS THE AREA AND SCT SHOWERS/TSTMS WILL FORM. WE ADDED TEMPO GROUPS IN FROM PHL NORTHWARD. WINDS THIS AFTERNOON W/SW AROUND 10-12 KTS. SEA BREEZE FRONT SHOULD STAY NEAR THE COAST AND BAY. THIS EVENING...SCT SHOWERS/TSTMS WILL DIMINISH BY 01-02Z AND THEN SKIES WILL BECOME MOSTLY CLR AS THEY DID MONDAY NIGHT. PATCHY FOG WILL BE POSSIBLE AGAIN AFTER MIDNIGHT. OUTLOOK... WEDNESDAY MORNING INTO THURSDAY MORNING...MOSTLY VFR WITH SHORT PERIODS OF SUB-VFR IN MORNING FOG AND/OR SCT SHOWERS/TSTMS. THURSDAY AFTERNOON THROUGH SATURDAY...MORE MVFR AND IFR CONDITIONS IN MORE NUMEROUS SHOWERS/TSTMS AS WELL AS MORNING LOW CLOUDS AND FOG. && .MARINE... THE RETURN FLOW BEHIND THE DEPARTING BERMUDA HIGH WILL KEEP A W/SW WIND ACROSS THE WATERS TODAY AND TONIGHT. WINDS/SEAS WILL REMAIN BELOW SCA CONDITIONS THRU THE PERIOD. FAIR WEATHER EXPECTED THIS MORNING...FOLLOWED BY SCT SHOWERS/TSTMS THIS AFTERNOON AND EARLY EVENING. FAIR WEATHER WILL RESUME LATER TONIGHT INTO WED MORNING. SEAS ON THE OCEAN WILL BE AROUND 2-4 FT AND 1-2 FT OVER DEL BAY. REMEMBER...WINDS AND WAVES WILL BE LOCALLY HIGHER IN TSTMS. OUTLOOK... SUB-SCA CONDITIONS ARE EXPECTED INTO THURSDAY MORNING. AFTER THAT THE FORECAST INCREASING SOUTHERLY FLOW MIGHT BRING SCA CRITERIA BASED ON SWELLS, MORE SO THAN WINDS, TO THE OCEAN WATERS LATER THURSDAY THROUGH FRIDAY. CONFIDENCE RIGHT NOW REMAINS LOWER THAN AVERAGE THAT THIS WILL OCCUR AS WAVE WATCH GUIDANCE OFTEN IS TOO BULLISH UNDER THESE REGIMES. && .CLIMATE... WE STAND A PRETTY GOOD CHANCE OF HAVING THE WETTEST JUNE ON RECORD IN PHILADELPHIA. WE LOOKED BACK AT THE 10 PREVIOUS WETTEST JUNES ON RECORD AND SAW HOW THE REST OF THE METEOROLOGICAL SUMMER WENT FORWARD. WET BEGETTED(SP) MORE WET. GIVEN HOW WET THE GFS AND ECMWF LOOK INTO THE START OF JULY THAT NOTION IS HOLDING. BOTH ENSUING MONTHS AVERAGED WETTER THAN THE CURRENT NORMALS WITH EIGHT OF THE TEN MONTHS COMBINED AVERAGING WETTER THAN NORMAL. ALL OF THE MONTHS HAD TWO INCHES OR MORE OF RAINFALL. AS FAR AS TEMPERATURES WENT, JULY AVERAGED SLIGHTLY LOWER THAN THE CURRENT NORMAL, WHILE AUGUST WAS VERY CLOSE TO THE CURRENT NORMAL. SIX OF THE TEN AUGUSTS WERE AS WARM OR WARMER THAN JULY. YEAR JULY AVG JULY AUG AVG AUGUST TEMP PCPN TEMP PCPN 1887 80.7 7.14 74.0 2.31 1906 75.6 5.33 76.2 9.56 1928 77.3 3.60 77.2 5.47 1938 77.3 6.52 78.3 4.10 1962 72.0 2.30 72.0 6.58 1969 75.1 8.33 75.2 2.66 1973 77.9 2.39 78.7 2.03 1975 76.6 6.32 77.0 2.11 2003 78.7 2.01 78.2 3.26 2006 79.4 4.27 78.1 3.93 AVG 77.1 4.82 76.5 4.20 1981-2010 NML 78.1 4.35 76.6 3.50 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...HEAVENER NEAR TERM...GIGI/O`HARA SHORT TERM...O`HARA LONG TERM...HEAVENER AVIATION...GIGI/O`HARA MARINE...GIGI/O`HARA CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
911 AM EDT TUE JUN 25 2013 .SYNOPSIS... BERMUDA RIDGE KEEPS THE REGION LOCKED IN A HOT AND HUMID AIRMASS THROUGH AT LEAST THE END OF THE WORK WEEK. A STRONG COLD FRONT WILL NEAR FROM THE NORTHWEST ON THURSDAY BUT BEGIN TO SLOW UPON ITS ARRIVAL. THE FRONT SHOULD LIMP THROUGH BY FRIDAY BUT THEN STALL TO OUR IMMEDIATE EAST THROUGH EARLY NEXT WEEK KEEPING A PROLONGED PERIOD OF UNSETTLED WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NOT MANY CHANGES WITH THIS ESTF UPDATE. LOOKS LIKE THE SPC WRF AND LATEST RAP ARE VERIFYING THE BEST WITH CONVECTION TO THE NORTHWEST, SO WE SCALED BACK THE TIMING OF ARRIVAL IN OUR CWA SLIGHTLY. BOTH HI RES NMM AND ARW LOOK TOO BULLISH WITH LEAD CONVECTIVE ACTIVITY. 12Z SOUNDINGS ARE AGAIN SHOWING PLENTY OF DRY AIR ABOVE THE SURFACE AND LESS OF AN INVERSION THAN YESTERDAY. SO WOULD EXPECT DEW POINTS TO DROP OFF QUICKER. FORECAST CONVECTIVE TEMPS ARE CLOSE (OR EVEN HIER) THAN SOUNDING FORECAST MAX TEMPS. THIS TOO POINTS TO WAITING FOR THE GREAT LAKES CONVECTION TO GET HERE VS HOME GROWN, THUS LATER TIMING. 500MB TEMPS ARE FORECAST TO BE ABOUT 3C WARMER THAN YESTERDAY, SO CONVECTION WILL HAVE A LESS HOSPITABLE AIR MASS TO BECOME VIGOROUS. MORNING SOUNDINGS SUGGEST MAYBE A 1-2F BUMP UP IN MAX TEMPS. THE COMBO IS STILL KEEPING OUR HEAT INDEX VALUES 90-95 BELOW HEADLINE CRITERIA FOR TODAY. FAIR WEATHER IS ACROSS THE REGION EARLY THIS MORNING AS SOME UPPER RIDGING HAS BUILT OVER THE AREA BEHIND YESTERDAYS SHORT WAVE. THIS RIDGING WILL PROBABLY KEEP THE AREA DRY THIS MORNING...BUT THEN THE DAYTIME HEATING AND THE LINGERING HUMIDITY ALONG WITH A WEAK SHORTWAVE MOVING THRU...WILL CREATE MORE SCT SHOWERS/TSTMS THIS AFTERNOON. THE COVERAGE OF THE ACTIVITY WILL NOT BE AS MUCH AS YESTERDAY...BUT THERE WILL BE ENOUGH TO KEEP THE CHC POPS IN THE FCST. THE UPPER WINDS WILL INCREASE SOMEWHAT THIS AFTERNOON...SO THE STORMS WILL HAVE A GREATER FORWARD (ERLY) MOTION. OUR CWA IS IN SPC`S GENERAL TSTM OUTLOOK FOR TODAY. TEMPERATURES WILL ONCE AGAIN REACH THE UPPER 80S TO LOW 90S ACROSS THE AREA. THIS WILL BE DAY2 OF OUR LATEST (EXPECTED) HEAT WAVE. DEW POINT READINGS WILL PROBABLY BE A BIT LESS THAN YDAY WITH A MORE WRLY FLOW ALOFT. WE DO NOT EXPECT THAT THE APPARENT TEMPS WILL BE GREAT ENOUGH FOR ANY HEAT RELATED HEADLINES TODAY...BUT CARE SHOULD STILL BE EXERCISED FOR THOSE WHO WILL BE OUTDOORS TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... ANY LINGERING SHOWER/TSTM ACTIVITY WILL DIMINISH THIS EVENING AND ANOTHER MILD/HUMID...BUT DRY FCST IS EXPECTED. LOWS WILL ONLY DROP INTO THE LOW 70S ACROSS THE METRO AREAS AND THE DELMARVA...WHILE UPPER 60S WILL BE FOUND ACROSS NRN NJ. PATCHY FOG IS POSSIBLE ... ESPECIALLY IN AREAS THAT RECEIVE SHOWERS TODAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... 5-WAVE MODEL GUIDANCE IS SHOWING A RATHER ROBUST BLOCKING PATTERN DEVELOPING ACROSS THE REGION. A LARGE RIDGE WILL PUSH INTO THE SOUTHWEST UNITED STATES WHILE THE RIDGING DOWNSTREAM OF OUR REGION AMPLIFIES ACROSS THE WESTERN ATLANTIC. THIS PLACES US IN A DEEPENING EAST COAST TROUGH THAT LOOKS TO DEEPEN WITH TIME. THIS WILL ALSO SLOW THE PROGRESSION OF ANY WEST-EAST MOVING SYSTEMS AND EFFECTIVELY KEEP US UNSETTLED HEADING INTO THE FIRST WEEK OF JULY. BEFORE THE BLOCKING GETS FULLY SETUP WE CONTINUE WITH A RATHER PROGRESSIVE PSEUDO-ZONAL FLOW ALOFT. THE JET STREAM STILL REMAINS LOCKED FAR TO OUR NORTH ALLOWING THE HEAT AND HUMIDITY TO CONTINUE FOR THE FIRST PART OF THE LONGTERM. THIS WILL PROVIDE THE CONTINUED ONSLAUGHT OF DIURNALLY DRIVEN CONVECTION ACROSS THE AREA WEDNESDAY AND THURSDAY. ON WEDNESDAY THE SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD WITHOUT MUCH UPPER LEVEL SUPPORT SO ORGANIZATION DOES NOT SEEM TO BE AN ISSUE THOUGH LOCALLY STRONG WIND GUSTS WITH VERY HEAVY RAIN CAN NOT BE RULED OUT. 850MB TEMPERATURES JUMP CLOSE TO 20C BUT STILL THINK THAT CLOUD COVER WILL PLAGUE THE REGION EARLIER ON WEDNESDAY THAN IN DAYS PAST. THERE COULD EVEN BE ON-GOING CONVECTION THROUGH THE MORNING HOURS TO HELP HAMPER HIGHS REACHING THE MID-90S. PLAYED IT A BIT MORE CONSERVATIVE AND WENT LOW-90S ACROSS THE METRO AREA WITH WARMER TEMPERATURES OVER THE WEST AS DOWNSLOPING SHOULD HELP TO WARM THEM A COUPLE MORE DEGREES. HEADING INTO THURSDAY WE START TO SEE THE ZONAL FLOW BREAK DOWN AS A MID-LEVEL IMPULSE DROPS ACROSS THE JET AND DRAGS TO INTO THE MID-WEST. THIS WILL ALLOW FOR VERY DEEP SOUTHWESTERLY FLOW TO SETUP ACROSS THE AREA AND WILL PUMP IN EVEN MORE MOISTURE. DECENT CYCLONIC FLOW ALOFT WILL INCREASE DURING THE DAY AS HEIGHTS BEGIN TO FALL AHEAD OF THE APPROACHING IMPULSE. THURSDAY IS SETTING UP TO BE AN ACTIVE DAY ACROSS THE REGION IN TERMS OF SEVERE WEATHER. SPC HAS PUT THE WESTERN PORTIONS OF THE CWA IN A SLIGHT RISK GIVEN THE AMOUNT OF SURFACE BASED INSTABILITY THAT WILL BE PRESENT AND BETTER UPPER LEVEL SUPPORT ALLOWING FOR MORE ORGANIZED CLUSTER OF STORMS. THURSDAY COULD ALSO BE THE LAST DAY OF 90+F WE SEE THIS WEEK, BUT THIS GREATLY DEPENDS ON THE AMOUNT OF CLOUD COVER AND THE TIMING OF THE CONVECTION. FRIDAY STILL LOOKS TO PROVIDE ANOTHER ROUND FOR SEVERE WEATHER AS THE COLD FRONT, TIED TO AN ADVANCING SURFACE LOW OVER THE GREAT LAKES, NEARS FROM THE NORTHWEST. THERE SHOULD STILL BE PLENTY OF INSTABILITY LEFT OVER FROM THURSDAY TO ALLOW FOR SURFACE BASED INITIATION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS WITH A FEW BREAKS IN THE OVERALL CLOUD COVER. TEMPERATURES WILL BE A FEW DEGREES COOLER ON FRIDAY THAN THURSDAY SO WE SHOULD BE ABLE TO BREAK THE CURRENT HEAT WAVE BY THEN. THE MID-LEVEL LOW SHOULD RETROGRADE A BIT DURING THE AFTERNOON HOURS ON FRIDAY SO WE LOSE A BIT OF THE COLD POOL INTERACTION BUT WE ALSO GAIN A MORE NEGATIVELY TILTED SHORTWAVE. THIS SETUP MAY MIMIC WHAT OCCURRED LATE LAST WEEK WHERE CONVECTION BEGAN LATE MORNING AND THEN FORMED INTO A LARGE BLOB OF SLOW MOVING HEAVY SHOWERS CAUSING FLASH FLOODING. GRANTED THERE IS THE LINEAR LIFTING ALONG THE COLD FRONT BUT IT REALLY DOES NOT FLY THROUGH THE REGION AND JUST SLOWLY LIMPS THROUGH. HEADING INTO THE WEEKEND WE KEEP THE MID-LEVEL TROUGH ENTRENCHED OVER THE REGION WITH PRETTY GOOD UPPER LEVEL DYNAMICS AS MULTIPLE WAVES RIDE UP THE EASTERN SEABOARD. THE UPPER JET WILL ALSO BE IN A GOOD SPOT WITH US IN ITS RIGHT ENTRANCE REGION FOR A PROLONGED TIME PERIOD. PWATS WILL STILL REMAIN VERY LARGE AND THUS WE CONTINUE TO RUN THE RISK FOR VERY HEAVY DOWNPOURS THROUGH AT LEAST EARLY NEXT WEEK. TEMPERATURES WILL BE MORE ON THE SEASONAL SIDE FROM FRIDAY ONWARD. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. AFTER SUNRISE SKIES WILL BE MOSTLY CLR WITH LIGHT W/SW WINDS EXPECTED. DURING THE AFTERNOON...CU WILL DEVELOP ACROSS THE AREA AND SCT SHOWERS/TSTMS WILL FORM. THE PROB30 FCST FROM EARLIER WAS LEFT IN THE 06Z TAFS. WINDS THIS AFTERNOON W/SW AROUND 10-12 KTS. THIS EVENING...SCT SHOWERS/TSTMS WILL DIMINISH BY 01-02Z AND THEN SKIES WILL BECOME MOSTLY CLR AS THEY DID MONDAY NIGHT. PATCHY FOG WILL BE POSSIBLE AGAIN AFTER MIDNIGHT. OUTLOOK... WEDNESDAY MORNING INTO THURSDAY MORNING...MOSTLY VFR WITH SHORT PERIODS OF SUB-VFR IN MORNING FOG AND/OR SCT SHOWERS/TSTMS. THURSDAY AFTERNOON THROUGH SATURDAY...MORE MVFR AND IFR CONDITIONS IN MORE NUMEROUS SHOWERS/TSTMS AS WELL AS MORNING LOW CLOUDS AND FOG. && .MARINE... THE RETURN FLOW BEHIND THE DEPARTING BERMUDA HIGH WILL KEEP A W/SW WIND ACROSS THE WATERS TODAY AND TONIGHT. WINDS/SEAS WILL REMAIN BELOW SCA CONDITIONS THRU THE PERIOD. FAIR WEATHER EXPECTED THIS MORNING...FOLLOWED BY SCT SHOWERS/TSTMS THIS AFTERNOON AND EARLY EVENING. FAIR WEATHER WILL RESUME LATER TONIGHT INTO WED MORNING. SEAS ON THE OCEAN WILL BE AROUND 2-4 FT AND 1-2 FT OVER DEL BAY. REMEMBER...WINDS AND WAVES WILL BE LOCALLY HIGHER IN TSTMS. OUTLOOK... SUB-SCA CONDITIONS ARE EXPECTED INTO THURSDAY MORNING. AFTER THAT THE FORECAST INCREASING SOUTHERLY FLOW MIGHT BRING SCA CRITERIA BASED ON SWELLS, MORE SO THAN WINDS, TO THE OCEAN WATERS LATER THURSDAY THROUGH FRIDAY. CONFIDENCE RIGHT NOW REMAINS LOWER THAN AVERAGE THAT THIS WILL OCCUR AS WAVE WATCH GUIDANCE OFTEN IS TOO BULLISH UNDER THESE REGIMES. && .CLIMATE... WE STAND A PRETTY GOOD CHANCE OF HAVING THE WETTEST JUNE ON RECORD IN PHILADELPHIA. WE LOOKED BACK AT THE 10 PREVIOUS WETTEST JUNES ON RECORD AND SAW HOW THE REST OF THE METEOROLOGICAL SUMMER WENT FORWARD. WET BEGETTED(SP) MORE WET. GIVEN HOW WET THE GFS AND ECMWF LOOK INTO THE START OF JULY THAT NOTION IS HOLDING. BOTH ENSUING MONTHS AVERAGED WETTER THAN THE CURRENT NORMALS WITH EIGHT OF THE TEN MONTHS COMBINED AVERAGING WETTER THAN NORMAL. ALL OF THE MONTHS HAD TWO INCHES OR MORE OF RAINFALL. AS FAR AS TEMPERATURES WENT, JULY AVERAGED SLIGHTLY LOWER THAN THE CURRENT NORMAL, WHILE AUGUST WAS VERY CLOSE TO THE CURRENT NORMAL. SIX OF THE TEN AUGUSTS WERE AS WARM OR WARMER THAN JULY. YEAR JULY AVG JULY AUG AVG AUGUST TEMP PCPN TEMP PCPN 1887 80.7 7.14 74.0 2.31 1906 75.6 5.33 76.2 9.56 1928 77.3 3.60 77.2 5.47 1938 77.3 6.52 78.3 4.10 1962 72.0 2.30 72.0 6.58 1969 75.1 8.33 75.2 2.66 1973 77.9 2.39 78.7 2.03 1975 76.6 6.32 77.0 2.11 2003 78.7 2.01 78.2 3.26 2006 79.4 4.27 78.1 3.93 AVG 77.1 4.82 76.5 4.20 1981-2010 NML 78.1 4.35 76.6 3.50 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...HEAVENER NEAR TERM...GIGI/O`HARA SHORT TERM...O`HARA LONG TERM...HEAVENER AVIATION...GIGI/O`HARA MARINE...GIGI/O`HARA CLIMATE...
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
130 AM EDT TUE JUN 25 2013 .UPDATE... /ISSUED AT 1107 PM EDT MON JUN 24 2013/ HAVE MADE SEVERAL TWEAKS TO GRIDS THROUGH THE EVENING...MAINLY TO UPDATE TRENDS IN POPS. REDUCED POPS SIGNIFICANTLY ESPECIALLY NORTH AND TRENDED THEM DOWN SOUTH AS WELL...WITH AN OVERALL REDUCTION THROUGH THE OVERNIGHT HOURS...TRENDING BACK UP DURING THE DAY ON TUESDAY. ADDED PATCHY FOG TO WEATHER GRID WORDING. UPDATED PRODUCTS ALREADY SENT. TDP && .PREV DISCUSSION... /ISSUED 339 PM EDT MON JUN 24 2013/ SHORT TERM /TONIGHT THROUGH TUESDAY/... 500MB SURFACE ANALYSIS SHOWS A TROUGH SITUATED ACROSS NORTHERN GA...CENTRAL AL AND SOUTHEAST MS. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED IN THE BASE OF THE TROUGH THIS AFTERNOON...AND CONTINUE TO APPROACH WESTERN GA. THE LATEST RUN OF THE HRRR HAS THE ACTIVITY FROM THE WEST CONGEALING WITH THE SE ACTIVITY LATE THIS AFTERNOON. ACTIVITY SHOULD DECREASE IN STRENGTH AND COVERAGE WITH THE LOSS OF HEATING FOR THE EARLY EVENING HOURS. FOR OVERNIGHT...WV LOOP SHOWS A GOOD PIECE OF SHORTWAVE ENERGY DROPPING SE IN THE FLOW ACROSS W KY THIS AFTERNOON. MODELS DO DEVELOP SCT ACTIVITY MAINLY ACROSS NORTHERN GA OVERNIGHT. WITH SOME MARGINAL INSTABILITY PRESENT OVERNIGHT...SCT SHRA/TSRA SEEM VERY REASONABLE. THE 500MB TROUGH AXIS IS PROGGED TO BE ACROSS THE CENTRAL CWFA DURING THE DAY TOMORROW. THIS SHOULD LEAD TO A LITTLE MORE COVERAGE OF STORMS ACROSS THE REGION. PWATS REMAIN THE SAME ACROSS NORTHERN GA...BUT WILL CREEP UP TO AROUND 2 INCHES ACROSS THE CENTRAL AND SOUTHERN CWFA. IN ADDITION...BL WINDS REMAIN VERY LIGHT (AOB 15K)...SO MOVEMENT OF STORMS WILL BE VERY SLOW OR NEARLY STATIONARY. EVEN THOUGH THE ATMOS WILL BE MARGINALLY UNSTABLE AT THE SURFACE...MID LEVEL LAPSE RATES AND SHEAR REMAIN VERY WEAK. THE POTENTIAL FOR SEVERE WEATHER REMAINS LOW...BUT STRONG THUNDERSTORMS ARE POSSIBLE...WITH AN ISOLATED SEVERE STORM NOT OUT OF THE QUESTION. NLISTEMAA LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... DIURNAL CONVECTION EXPECTED TO CONTINUE ACROSS THE AREA EACH AFTERNOON AND EVENING THROUGH DAY 7. MODELS IN GOOD AGREEMENT WITH SURFACE RIDGE LOSING ITS GRIP ON THE SOUTHEAST BY WEEKS END. THEY ARE ALSO IN GOOD AGREEMENT WITH THE UPPER LEVEL RIDGE BUILDING AND REMAINING OVER THE WESTERN US AS LONG WAVE TROUGH SETS UP OVER THE EAST COAST BY FRIDAY. WITH THE EASTERN EXTENT OF THE UPPER LEVEL RIDGE MORE LIMITED THAN PREVIOUSLY EXPECTED...HAVE COOLED EXTENDED HIGH TEMPERATURES A DEGREE OR TWO. STILL LOOKING FOR HIGHS IN THE UPPER 80S AND LOW 90S. HAVE INCREASED POPS SOMEWHAT FOR THE WEEKEND...AND EXPECT THIS UPWARD TREND IN THE FORECAST TO CONTINUE IN THE COMING DAYS. ENHANCED MOISTURE ACROSS THE REGION AS A RESULT OF THE UPPER LEVEL TROUGH AND ASSOCIATED FRONTAL BOUNDARY SHOULD SUPPORT MORE SIGNIFICANT COVERAGE OF PRECIP ACTIVITY. ANTICIPATE FRONTAL PASSAGE BY EARLY NEXT WEEK...WITH DROP IN POPS AND SLIGHTLY COOLER TEMPERATURES IN STORE AS A RESULT. 31/01 && .AVIATION... 06Z UPDATE... ANOTHER SHORT WAVE WILL MOVE ACROSS THE FORECAST AREA THIS AFTERNOON BRINGING SCATTERED TO NUMEROUS THUNDERSTORMS TO THE FORECAST AREA...MAINLY AFTER 20Z. HIGHEST CHANCE WILL BE IN THE AHN/MCN/CSG. WINDS WILL BE LIGHT WEST THROUGH THE FORECAST. CURRENT ALL CIGS VFR BUT EXPECT MVFR CIGS TO DEVELOP THIS MORNING. AREAS OF FOG ARE EXPECTED TO DEVELOP THIS MORNING...ESPECIALLY IN AREAS THAT HAD RAINFALL YESTERDAY. SOME VSBYS COULD DROP TO IFR BUT MOST SHOULD STAY MVFR. //ATL CONFIDENCE...06Z UPDATE... MEDIUM-LOW ON CIGS THIS MORNING. HIGH ON OCCURRENCE OF CONVECTION TODAY...MEDIUM ON IMPACTS TO ATL. HIGH ON ALL REMAINING ELEMENTS. 17 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 69 87 69 90 / 30 50 30 30 ATLANTA 70 86 71 88 / 30 50 30 30 BLAIRSVILLE 64 81 64 86 / 40 50 20 40 CARTERSVILLE 69 88 69 89 / 20 50 20 30 COLUMBUS 71 91 72 92 / 50 40 30 30 GAINESVILLE 68 85 70 87 / 20 50 30 30 MACON 71 89 71 90 / 60 50 30 30 ROME 68 89 69 91 / 20 40 10 30 PEACHTREE CITY 69 87 69 88 / 30 50 30 30 VIDALIA 72 88 73 92 / 50 50 30 30 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
317 PM CDT TUE JUN 25 2013 .DISCUSSION... ISSUED 300 PM CDT TUE JUN 25 2013 SEVERE STORM CHANCES WILL REMAIN THE FOCUS OVER THE NEXT 2 DAYS. FLASH FLOODING POTENTIAL TONIGHT IN THE NORTH WILL ALSO BE A CONCERN. BEYOND THAT...AN AIRMASS CHANGE IS PROJECTED FOR LATE THIS WEEK AND WEEKEND. HOWEVER...A CUTOFF UPPER LOW LINGERING OVER THE HEARTLAND WILL KEEP SHOWERS AND EVEN ISOLATED THUNDERSTORMS IN THE FORECAST THROUGH EARLY NEXT WEEK. SHORT TERM...TONIGHT THROUGH FRIDAY. WE DECIDED TO PUT OUR 5 NORTHERN COUNTIES IN A FLASH FLOOD THROUGH TONIGHT DUE TO PREVIOUS 3-5 INCH RAINS EARLY MONDAY MORNING AND THE POTENTIAL FOR ADDITIONAL VERY HEAVY RAINFALL RATES UP TO 2 INCHES AN HOUR WITH ANY THUNDERSTORMS THROUGH TONIGHT. PWATS REMAIN IN THE 1.7-1.9" RANGE...AND PERIODIC STORMS IN AN EAST-WEST LINE ACROSS N IL IS POSSIBLE. ADJUSTING OUR 12Z SOUNDING FOR CURRENT CONDITIONS SHOWS ML-CAPE VALUES APPROACHING 3500 J/KG ACROSS OUR AREA...WITH LITTLE TO NO CIN. VARIOUS BOUNDARIES ACROSS THE AREA FROM YESTERDAYS CONVECTION HAVE ALREADY BEGUN TO FIRE BETWEEN 18-19Z. WATER VAPOR PIX CONFIRM A SHORTWAVE IN THE FLOW ACROSS IOWA PROGRESSING EAST-NE. THAT WAVE SHOULD HELP RAMP UP THE COVERAGE OF STORMS AND POSSIBLY PUSH US INTO SEVERE WEATHER MODE. FREEZING LEVEL AT 14.4K FT MEANS HAIL WILL NEED INTENSE UPDRAFTS TO REACH SEVERE LEVELS /1"+/...BUT WE HAVE THE CAPE TO ACCOMPLISH THAT WITH THE STRONGEST STORMS. WIND SHEAR WILL BE GRADUALLY INCREASING AS WE HEAD INTO THIS EVENING...SO ROTATING SUPERCELLS WILL BE POSSIBLE AS THE EVENT PROGRESSES. THE LATEST HRRR IS INDICATING TWO PERIODS OF STORMS POSSIBLE. WE EXPECT A WAVE OF STORMS THIS EVENING THAT MAY BE FOLLOWED BY ANOTHER BOWING COMPLEX OF STORMS ROLLING INTO OUR AREA FROM IOWA REACHING KNOX COUNTY AROUND 06Z/1AM. THOSE STORMS MAY BE STILL AFFECTING OUR COUNTIES SE OF I-70 WED MORNING BEFORE THEY DEPART INTO INDIANA. WE WENT WITH SOME LIKELY POPS IN THE MORNING TO ACCOUNT FOR THAT. THEN A BREAK IN THE ACTION MAY DEVELOP THE REST OF WED MORNING AS THE ATMOSPHERE RECHARGES FOR THE AFTERNOON WAVE OF STRONG TO SEVERE STORMS. IT APPEARS THAT A LINE OF STORMS WILL DEVELOP ACROSS WEST CENTRAL ILLINOIS BY MID AFTERNOON...THEN PROGRESS EASTWARD. AN INCREASING LLJ IS EXPECTED TO COINCIDE WITH UPPER LEVEL WINDS VEERING TO THE NORTHWEST. THAT WILL INCREASE SHEAR AND HELICITY PARAMETERS AND RAMP UP THE THREAT OF ROTATING STORMS AND POSSIBLY A FEW TORNADOES...MAINLY EAST OF I-55. WE INCREASED POPS TO LIKELY IN THE EAST WEDNESDAY AFTERNOON TO ACCOUNT FOR THAT PERIOD OF SEVERE STORMS. STORMS SHOULD BE WINDING DOWN WED EVENING AS THE COMPLEX MOVES INTO INDIANA. THURSDAY AND THURSDAY NIGHT SHOULD BE PRIMARILY DRY...BUT A FEW DAYTIME SHOWERS WILL BE POSSIBLE IN THE EAST AS THE UPPER WAVE LINGERS ACROSS THE EAST...AND A FEW SHOWERS MAY REACH OUR SOUTHWESTERN COUNTIES THUR NIGHT AHEAD OF THE NEXT UPPER LEVEL WAVE. WE KEPT SLIGHT CHANCE POPS EVERYWHERE ON FRIDAY AS THAT WAVE PROGRESSES ACROSS IL. PRECIP SHOULD BE SPOTTY...AS COOLER AND LESS HUMID AIR BEGINS TO FLOW INTO THE AREA ON NORTHWEST WINDS. LONG TERM...SATURDAY THROUGH TUESDAY. WE EXPECT TO BE IN AN EXTENDED PERIOD UP UPPER LEVEL TROUGHING AS A CUT OFF LOW DEVELOPS ACROSS THE WESTERN GREAT LAKES AND RETROGRADES AND OSCILLATES OVER THE MIDWEST THROUGH EARLY NEXT WEEK. PERIODS OF SLIGHT CHANCE AND CHANCE POPS WILL PEPPER THE EXTENDED FORECAST AS A RESULT...DUE TO VARIOUS SHORTWAVE ROTATING AROUND THE UPPER LOW. RELATIVELY COOL AIR ALOFT WILL ALSO KEEP LAPSE RATES MODERATELY HIGH...AND FAVORABLE FOR ANY SUNS HEATING TO CREATE SHOWERS AND ISOLATED STORMS. TEMPS WILL SETTLE OUT WITH HIGHS IN THE UPPER 70S TO NEAR 80 AND LOWS IN THE LOWER 60S FOR MUCH OF THE EXTENDED PERIOD. SHIMON && .AVIATION... ISSUED 1252 PM CDT TUE JUN 25 2013 PERIODS OF THUNDERSTORMS ARE EXPECTED AT ALL OF THE TAF SITES IN CENTRAL AND EASTERN IL THE NEXT 24 HOURS. THE HIGH RESOLUTION MODELS LIKE THE HRRR...RUC AND LOCAL WRF ARE IN FAIR AGREEMENT THAT AT LEAST SCT CONVECTION WILL DEVELOP LATER THIS AFTERNOON IN WEST CENTRAL IL...IN RESPONSE TO ABUNDANT INSTABILITY AND A SHORTWAVE NOW MOVING TOWARD CENTRAL MO...AND IMPACT THE TAF SITES AROUND 21-23Z. AM ANTICIPATING A BRIEF RESPITE IN THE CONVECTION AS THE ATMOSPHERE LIKELY STABILIZES...DUE TO RAIN FROM LATER AFTERNOON STORMS...AROUND OR SHORTLY AFTER SUNSET. LATER IN THE EVENING AND OVERNIGHT...THE SHORT RANGE AND HIGH RESOLUTION MODELS ARE IN FAIR AGREEMENT THAT SCT CONVECTION WILL REDEVELOP CLOSE TO OR SHORTLY AFTER MIDNIGHT IN RESPONSE TO AMPLE LOW LEVEL MOISTURE AND INCREASING LOW LEVEL WINDS/MOISTURE TRANSPORT. AT THIS TIME IT APPEARS THAT THE MOST LIKELY AREA TO EXPERIENCE THIS WILL BE IN THE NORTHERN TAF SITES FROM KPIA-KBMI. AM CONFIDENT THIS WILL IMPACT THESE AREAS...SO WENT WITH A PREDOMINANT TSRA GROUP FOR A FEW HOURS BEFORE DAYBREAK. CONFIDENCE WANES WITH SOUTHWARD AND EASTWARD EXTENT AS THE MODELS DO NOT AGREE ON THE PROPAGATION OF THE STORMS. MILLER && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR ILZ027>031. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
243 AM CDT TUE JUN 25 2013 .DISCUSSION... ISSUED 240 AM CDT TUE JUN 25 2013 SHORT TERM...TODAY THROUGH WEDNESDAY... MAIN CONCERNS IN THIS PERIOD ARE WITH SEVERE WEATHER POTENTIAL... ESPECIALLY ON WEDNESDAY. DAY1 CONVECTIVE OUTLOOK SHOWS THE SLIGHT RISK FROM ABOUT I-72 NORTHWARD TODAY. LATEST IN THE SERIES OF NOCTURNAL MCS SYSTEMS WAS TRACKING ALONG THE ILLINOIS/WISCONSIN BORDER AT 2 AM. WHILE HIGHER RESOLUTION MODEL GUIDANCE KEEPS THE TRACK OF THIS WELL TO OUR NORTH...RADAR MOSAICS STARTING TO SHOW THE OUTFLOW BOUNDARY DROPPING SOUTHWARD THROUGH NORTHERN ILLINOIS. THE AIR TO THE SOUTH WILL BECOME QUITE UNSTABLE LATER TODAY WITH CAPES OF OVER 3000 J/KG. ANOTHER MCS PROGGED TO DEVELOP TO THE NORTHWEST AS A SHORTWAVE MOVES IN FROM THE PLAINS...WITH THIS MCS SLIDING ACROSS THE NORTH HALF OF ILLINOIS LATER TODAY. HIGHER PROBABILITIES ARE FOCUSED MORE ON THE I-80 CORRIDOR. STORMS THAT DO FORM WILL AGAIN HAVE THE POTENTIAL FOR HEAVY RAIN...WITH PRECIPITABLE WATER VALUES OF AROUND 1.8 INCHES. SPC PROBABILITY GRAPHICS FOR THE DAY2 OUTLOOK SHOW A SEVERE WEATHER THREAT OVER ALL OF OUR AREA BUT FOCUS ON LOCATIONS ALONG AND EAST OF I-57 WITH THE HIGHEST THREAT FOR SEVERE WEATHER ON WEDNESDAY...INCLUDING VERY LARGE HAIL AND DAMAGING WINDS. COLD FRONT SHOULD BE CROSSING THE STATE DURING THE AFTERNOON. AIR MASS WILL BE EXTREMELY UNSTABLE AHEAD OF IT...WITH CAPES OF AROUND 4500 J/KG AND 0-6KM BULK SHEAR OF 30-40 KNOTS. PRECIPITABLE WATER VALUES OF AROUND 1.8 INCHES POINT TO POTENTIAL FOR HEAVY RAIN ONCE AGAIN...BUT HOPEFULLY THE STORMS ON WEDNESDAY WILL BE MORE PROGRESSIVE AS COMPARED TO THE LAST FEW DAYS. HIGH TEMPERATURE FORECASTS THE LAST FEW DAYS HAVE BEEN A REAL STRUGGLE WITH ALL OF THE CONVECTION IN THE AREA. HAVE SCALED BACK HIGHS A COUPLE DEGREES...GOING CLOSER TO A MET/MAV BLEND. IF THE CONVECTION TODAY IS MORE ISOLATED...THEN THE WARMER MAV NUMBERS SHOULD BE ATTAINABLE. LONG TERM...THURSDAY THROUGH MONDAY... INITIAL COLD FRONT ON WEDNESDAY WILL BE A BIT OF A TEASE...WITH VERY WARM AND HUMID CONDITIONS CONTINUING INTO THURSDAY. A STEADY PUSH OF COOLER AIR SHOULD BEGIN TO SPREAD IN ON FRIDAY AS AN UPPER LOW OVERSPREADS THE GREAT LAKES...AND STARTS A PERSISTENT NORTHWEST FLOW OVER THE MIDWEST. BOTH THE GFS AND ECMWF MODELS SHOW A SIGNIFICANT UPPER TROUGH BEING CARVED OUT OVER THE MIDWEST AND LOWER MISSISSIPPI VALLEY THIS WEEKEND...WITH THE LATTER MODEL A BIT MORE PERSISTENT AND LASTING THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL...BUT NOT ABNORMALLY OUT OF LINE FOR THE END OF JUNE. BLENDED MODEL GUIDANCE SHOWS SLIGHT CHANCE POPS FOR MUCH OF THE FRIDAY THROUGH MONDAY PERIOD. WITH THE COLDER AIR ALOFT AND THE DEEP TROUGH OVERHEAD...AM RELUCTANT TO COMPLETELY REMOVE RAIN CHANCES...ALTHOUGH THEY WOULD BE MORE DIURNAL IN NATURE. GEELHART && .AVIATION... ISSUED 1204 AM CDT TUE JUN 25 2013 TEMPO IN FOR TSRA BETWEEN 09 AND 14Z AS THE NAM IS SIGNALING A SOUTHERLY PUSH TO THE CONVECTION CURRENTLY OVER SE WI. WITH HRRR AND RUC BOTH DRY AND THE MODEL PERFORMANCE ABYSMAL WITH THE MCS TRAIN OF LATE...FORECAST CONFIDENCE IS LOW BUT TREND/PERSISTENCE BASED. THE LATEST 4KM WRF KEEP CONVECTION AWAY UNTIL MIDDAY. SOUTHERLY COMPONENT TO THE LINE OF STORMS TO THE NORTH ARE DRIVING THE NEXT 6 HRS. VCTS FROM MID MORNING ON THROUGH THE FORECAST AS THE ENTIRE 24 HRS HINGES ON MESOSCALE BOUNDARY INTERACTIONS AND REMNANT MCVS. AHEAD OF STORMS...VFR CONTINUES...AS WELL AS RAPID CLEARING BEHIND THEM. TOMORROW EXPECTED TO BE BUSY AGAIN WITH THUNDER WIDESPREAD ACROSS THE AREA. THOUGH TIMING INDIVIDUAL CELLS/TERMINALS IS VERY PROBLEMATIC. HJS && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1210 AM CDT TUE JUN 25 2013 .DISCUSSION... ISSUED 855 PM CDT MON JUN 24 2013 ANOTHER MCS EXITING THE CWA THIS EVENING...LEAVING A COOLER AND MORE HUMID BOUNDARY LAYER IN ITS WAKE. WILL BE ADJUSTING THE HOURLY TEMPS AND OVERNIGHT LOWS AS WELL AS SOME OF THE AREA WILL BE SEEING THEIR LOWS NOW...IN THE REMAINING COLD AIR FROM CONVECTION. SOUTHERLY WINDS WILL BRING IN WARMER TEMPS FROM THE SOUTH TO COUNTER ANY ADDITIONAL RADIATIONAL COOLING AFTER SUNSET. WILL WATCH CLOSELY FOR DEVELOPMENT OF FOG...BUT SHOULD REMAIN PATCHY IF IT DEVELOPS. ADDITIONAL SHOWER ACTIVITY REMAINING TO THE NORTH IN HRRR AND THE RUC...BUT WITH SO MANY BOUNDARIES OUT THERE FROM DYING CONVECTION...WILL MAINTAIN A LOW POP OVERNIGHT AFTER 06Z. && .AVIATION... ISSUED 1204 AM CDT TUE JUN 25 2013 TEMPO IN FOR TSRA BETWEEN 09 AND 14Z AS THE NAM IS SIGNALING A SOUTHERLY PUSH TO THE CONVECTION CURRENTLY OVER SE WI. WITH HRRR AND RUC BOTH DRY AND THE MODEL PERFORMANCE ABYSMAL WITH THE MCS TRAIN OF LATE...FORECAST CONFIDENCE IS LOW BUT TREND/PERSISTENCE BASED. THE LATEST 4KM WRF KEEP CONVECTION AWAY UNTIL MIDDAY. SOUTHERLY COMPONENT TO THE LINE OF STORMS TO THE NORTH ARE DRIVING THE NEXT 6 HRS. VCTS FROM MID MORNING ON THROUGH THE FORECAST AS THE ENTIRE 24 HRS HINGES ON MESOSCALE BOUNDARY INTERACTIONS AND REMNANT MCVS. AHEAD OF STORMS...VFR CONTINUES...AS WELL AS RAPID CLEARING BEHIND THEM. TOMORROW EXPECTED TO BE BUSY AGAIN WITH THUNDER WIDESPREAD ACROSS THE AREA. THOUGH TIMING INDIVIDUAL CELLS/TERMINALS IS VERY PROBLEMATIC. HJS && .PREV DISCUSSION... ISSUED 300 PM CDT MON JUN 24 2013 THE SHORT TERM THROUGH WEDNESDAY WILL BE DOMINATED BY PERIODIC BOUTS OF SEVERE STORMS AND FLASH FLOODING...ALONG WITH HIGH HEAT AND HUMIDITY. A COLD FRONT SHOULD PUSH ACROSS ILLINOIS LATE IN THE WEEK PROVIDING SOME RELIEF FROM THE HEAT AND HUMIDITY AND DAILY THUNDERSTORMS. MUCH MORE COMFORTABLE CONDITIONS SHOULD DEVELOP NEXT WEEKEND. BASED ON THE 3-5" OF RAIN FROM PEORIA AND NORTH...WE DECIDED TO INCLUDE OUR NORTHERN 5 COUNTIES IN A FLASH FLOOD WATCH THROUGH TONIGHT DUE TO THE HEAVY RAIN POTENTIAL AGAIN. SHORT TERM...TONIGHT THROUGH WEDNESDAY. INITIAL SEVERE STORM WATCH IS IN EFFECT UNTIL 7 PM FOR OUR WESTERN COUNTIES BUT ANOTHER WATCH FOR AREAS NORTHEAST OF THAT WATCH MAY BE COMING SOON. BASED ON RADAR ANALYSIS...THE SOUTHERN END OF THE LINE OF STORMS IN N MO AND E IOWA APPEARS TO BE ERODING EARLY ON. WE COULD SEE ADDITIONAL DEVELOPMENT ON THE SOUTHERN FLANK AIDED BY INCREASING MID-LEVEL FLOW AND MOISTURE CONVERGENCE. IF NOT...THE SOUTHERN COUNTIES IN THE WATCH WILL NOT BE AFFECTED AS MUCH WITH THIS ROUND OF STORMS. CORFIDI VECTORS ARE SHOWING THE LINE SHOULD MAINTAIN ITS MOTION TO THE EAST-NORTHEAST AS IT MOVES ACROSS IL...WHICH WILL MAKE IT MU-CAPE VALUES ARE CLIMBING TO NEAR 3000 J/KG AS SUNSHINE AHEAD OF THE LINE HAS HELPED BOOST SURFACE TEMPERATURES INTO THE UPPER 80S WITH SURFACE DEWPOINTS IN THE LOWER 70S. SURFACE BASED CONVECTION WILL AID IN DOWNBURST WINDS BEING ABLE TO REACH THE GROUND. SPC MESO-ANALYSIS SHOWS DOWNBURST CAPE VALUES AROUND 1100 J/KG...WHICH ALSO POINTS TOWARD EFFICIENT MOMENTUM TRANSFER TO THE SURFACE AND DAMAGING WINDS. WITH VGP ABOVE 0.2 ACROSS OUR NORTHERN COUNTIES...WE COULD SEE SOME ROTATING EMBEDDED SUPERCELLS WITH A TORNADO POSSIBLE. THE LINE OF STORMS SHOULD REACH OUR WESTERN COUNTIES AROUND 4 PM...AND PROGRESS EASTWARD TO NEAR BMI BY 6 PM AND INTO INDIANA BY 8-9 PM. STRATIFORM RAIN BEHIND THE LINE MAY LINGER FOR A FEW HOURS. SATELLITE IMAGES SHOW A WEAK SHORTWAVE IN THE WAKE OF THIS COMPLEX...SO A FEW ADDITIONAL THUNDERSTORMS MAY AFFECT OUR NW COUNTIES THROUGH MORNING. THEREFORE WE KEPT CHANCE POPS IN THE NW AFTER MIDNIGHT. ANOTHER ROUND OF SEVERE STORMS WILL BE POSSIBLE ON TUESDAY...MAINLY NORTH OF I-72/74-DANVILLE. WE ORIGINALLY HAD EXPECTED SOME UPPER LEVEL RIDGING TO PROVIDE A BREAK IN THE STORMS...AND WE STILL MAY SEE DRY CONDITIONS FOR MUCH OF THE DAY. HOWEVER...SPC HAS EXPANDED THE DAY 2 SLIGHT RISK FARTHER SOUTH TO INCLUDE A LARGE PORTION OF OUR FORECAST AREA...SO WE DECIDED TO ACKNOWLEDGE THE SEVERE POTENTIAL WITH SLIGHTLY HIGHER POPS. WE WILL HAVE A BETTER CHANCE OF BEING CAPPED TUES AS THE MID LEVELS WARM. HOWEVER...ISOLATED AREAS THAT DO BREAK THE CAP WILL HAVE A GREAT DEAL OF ML-CAPE FOR VIGOROUS UPDRAFTS. WE STILL MAINLY HAVE SLIGHT CHANCE POPS EXCEPT FOR NORTH OF I-74 WHERE WE WENT WITH CHANCE POPS. WEDNESDAY SHOULD SEE INCREASING BETTER DESTABILIZATION OF THE LOWER TROP AS THE UPPER RIDGE BEGINS TO BREAK DOWN IN RESPONSE TO A PROGRESSIVE TROUGH FROM CANADA. SURFACE HEAT AND HUMIDITY WILL REMAIN HIGH...BUT SUNSHINE MAY BE A BIT MORE LIMITED IF CONVECTION DEVELOPS EARLIER IN THE AFTERNOON. TUES AND WED WILL HAVE POTENTIAL FOR HEAT INDEX READINGS AROUND 100 IN MANY AREAS BASED ON THE AMOUNT OF SUNSHINE AND WHERE THE CIRRUS SHIELD DEVELOPS AHEAD OF CONVECTION. STILL...VERY UNCOMFORTABLE CONDITIONS. LONG TERM...THURSDAY THROUGH MONDAY. THE MODELS ALL SHOW A COLD FRONTAL PASSAGE AT SOME POINT BEGINNING LATE WED NIGHT OR THURSDAY...BUT THE ARRIVAL OF COLDER AIR DELAYED UNTIL FRIDAY INTO FRIDAY NIGHT AS A SECONDARY PUSH OF CANADIAN AIR OCCURS. WE MAY SEE A FEW SHOWERS OR STORMS IN THE EAST THURSDAY AS THE COLD FRONT DEPARTS...WITH A BREAK IN THE RAIN LATER THURS AND THURS NIGHT. AS A REINFORCING SHORTWAVE IN THE 500 MB TROUGH ROUNDS THE BACK SIDE OF THE SYSTEM...IT IS PROJECTED TO BECOME CUT OFF AND LINGER ACROSS THE WESTERN GREAT LAKES THROUGH EARLY NEXT WEEK. THAT WOULD LIKELY KEEP RAIN SHOWER CHANCES ACROSS OUR AREA FOR MUCH OF THAT TIME...AS THE COLD POOL PROVIDES FAVORABLE LAPSE RATES FOR UPDRAFTS. SO A CHANGE FROM HEAT AND HUMIDITY TO CLOUDY AND COOLER APPEARS IN THE OFFING. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
647 PM CDT WED JUN 26 2013 .UPDATE... ISSUED AT 646 PM CDT WED JUN 26 2013 DESPITE HIGH CAPES OVER THE AREA AND LINGERING SURFACE BOUNDARIES... SHOWERS AND THUNDERSTORMS HAVE DIMINISHED TO ISOLATED CELLS THE SOUTH EARLY THIS EVENING. WITH PASSAGE OF PRIMARY SURFACE TROUGH AND A WEAK MID LEVEL IMPULSE EARLY THIS EVENING...LITTLE REDEVELOPMENT IS ANTICIPATED AND WILL BE UPDATING TO TRIM BACK THE ALREADY LOW POPS THIS EVENING. && .SYNOPSIS... ISSUED AT 334 PM CDT WED JUN 26 2013 18Z SFC ANALYSIS HAS THE REMNANTS OF A MESO HIGH AT KDBQ AND A MESO LOW BETWEEN KSQI AND KFEP. AN OUTFLOW BOUNDARY FROM THE MCS RAN FROM LAKE MICHIGAN THROUGH CENTRAL ILLINOIS AND THEN TO NEAR KMXO. THE SYNOPTIC COLD FRONT RAN FROM NEAR KMSP...TO KDSM...TO KFNB. AHEAD OF THE SYNOPTIC FRONT SEVERAL WEAK TROFS/BOUNDARIES WERE ACROSS EASTERN IOWA AND MISSOURI. DEW POINTS WERE IN THE 70S WITH 60S OVER THE GREAT LAKES AND BEHIND THE COLD FRONT. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 334 PM CDT WED JUN 26 2013 DIURNAL CONVECTION HAS FIRED ALONG A THETA E GRADIENT IN CENTRAL IOWA AND ALONG A PRE-FRONTAL TROF. RAP TRENDS BRING THIS FEATURE INTO THE WESTERN CWFA LATE THIS AFTERNOON BEFORE WEAKENING THE THETA E GRADIENT. THUS THE NEW STORMS THAT HAVE DEVELOPED JUST WEST OF THE CWFA ARE EXPECTED TO MOVE INTO THE WESTERN CWFA DURING THE LATE AFTERNOON HOURS AND THEN SLOWLY DISSIPATE WITH SUNSET. AHEAD OF THIS CONVECTION...ISOLATED SHOWERS AND STORMS ARE EXPECTED TO DEVELOP DURING PEAK HEATING THAT WILL ALSO SLOWLY DISSIPATE WITH SUNSET. THE SYNOPTIC COLD FRONT WILL MOVE THROUGH THE CWFA TONIGHT DROPPING DEW POINTS ABOUT 5 TO 7 DEGREES. WINDS ARE EXPECTED TO BE FAIRLY LIGHT AND GIVEN THE WET GROUND IN SOME AREAS THERE IS A POTENTIAL FOR SOME FOG DEVELOPMENT AFTER MIDNIGHT. THIS WILL HAVE TO BE WATCHED TO SEE HOW IT WILL EVOLVE. QUIET AND DRY CONDITIONS WILL BE SEEN THURSDAY MORNING ACROSS THE AREA WHILE AN UPPER LOW MOVES INTO THE NORTHERN GREAT LAKES. DAY TIME HEATING COMBINED WITH SLIGHTLY COOLER AIR ALOFT SHOULD ALLOW NEW CONVECTION TO DEVELOP DURING THE AFTERNOON. THE LOWER MOISTURE LEVELS IN THE ATMOSPHERE AND NORTHWEST FLOW SHOULD RESULT IN THE CONVECTION BEING ISOLATED TO SCATTERED IN NATURE. ..08.. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 334 PM CDT WED JUN 26 2013 THURSDAY NIGHT AND FRIDAY...AS NORTHWESTERLY STEERING FLOW TAKES OVER WITH UPPER RIDGE RETROGRADE...DIGGING UPPER WAVE INTO THE NORTHWESTERN GRT LKS WILL CONNECT WITH TROF INTO THE CENTRAL PLAINS FOR CONTINUED ISOLATED TO WDLY SCTRD SHOWER/STORM THREAT INTO MID THU EVENING. BUT BEST FORCING AND CONVERGENCE TO REMAIN JUST TO THE NORTHEAST AND SOUTHWEST OF THE DVN CWA. WILL EXTEND LOW CHC POPS IN THE FAR EAST AND MAINTAIN ONGOING POPS IN THE SOUTHWESTERN CWA THROUGH 03Z FRI. AFTER TROF EMBEDDED IN NW STEERING FLOW PASSES...EXPECT SOME CLEARING AND COOLER CONDITIONS INTO EARLY FRI MORNING WITH LOWS WELL DOWN INTO THE 60S...POSSIBLY SOME LOWER 60S NORTH OF I80. LARGE UPPER CYCLONE COMPLEX TO THEN CONTINUE TO SETTLE ACRS THE HEART OF THE GRT LKS ON FRI. ASSOCIATED VORT SPOKE ALOFT AND MID LEVEL COOL POOL TO INDUCE DEEP STEEP LAPSE RATES AND A INSTABILITY SHOWER SET UP ACRS MN INTO WI AND IL. SOME POTENTIAL FOR THUNDERSTORMS WITH VERTICAL THERMODYNAMIC PROFILES SUPPORTIVE OF HAIL IF ENHANCED UPDRAFTS CAN MAINTAIN. THIS ACTIVITY MORE LIKELY FRIDAY AFTERNOON ACRS THE NORTHEASTERN THIRD OF THE DVN CWA AND WILL ADJUST POPS ACCORDINGLY. DESPITE INCOMING COOLER AIR INFLUX/ ADVECTION...DEEP MIXING PROFILES UP TO H8 MB STILL TO BOOST TEMPS INTO THE LOW TO MID 80S WHILE SFC DPTS DRY-DOWN MIX INTO THE LOWER 60S TO UPPER 50S...MAYBE LOWER THAN GUIDANCE SUGGESTS INTO THE MID 50S. BREEZY NORTHWEST WINDS AS WELL IN THIS SCENARIO OF 15 TO 20+ MPH. TIGHTENING CYCLONIC FLOW ALOFT MAY KEEP SHOWERS PECULATING WELL INTO FRI EVENING BEFORE NOCTURNAL PROCESSES TAKE OVER. EVEN WITH CLOUD DEBRIS...STILL A COOLER NIGHT WITH WIDESPREAD LOWS IN THE LOW TO MID 60S. SATURDAY AND SUNDAY...UNSTABLE VERTICAL PROFILES UNDER ONGOING CYCLONIC FLOW AND ANOTHER INCOMING VORT SPOKE MAY PRODUCE MORE WIDESPREAD SHOWERS AND A FEW STORMS/FURTHER TO THE WEST/THEN ON FRIDAY. CANADIAN LLVL RIDGE AXIS DUMPING DOWN TO THE WEST OF THE AREA ACRS THE PLAINS. FCST SOUNDING SUGGEST ANOTHER DAY OF DEEP MIXING... BUT CONTINUED LLVL COOL POOL INFLUX AS WELL AS SHOWERS/CLOUDS WILL HAVE A BETTER SHOT TO KEEP TEMPS IN THE 70S. CLEAR OUT SAT NIGHT AS LARGE STOUT CANADIAN HIGH TAKES GRIP OF THE UPPER MIDWEST AND COULD FOSTER WIDESPREAD LOWS WELL DOWN IN THE 50S BY EARLY SUNDAY MORNING. HIGH PRESSURE TO THEN TO MIGRATE TOWARD THE GRT LKS ON SUNDAY...WHILE ALOFT DEEP LONG WAVE TROF EXTENDS TO THE GULF ALONG AND EAST OF THE MS RVR VALLEY. APPEARS LESSENING CHANCE OF SHOWERS SUNDAY AND BOUNDARY LAYER NORTHEASTERLY FETCH AGAIN TO POSSIBLY KEEP TEMPS IN THE 70S FOR HIGHS. SUNDAY NIGHT SEASONABLY COOL AND WELL DOWN IN THE 50S ALONG AND NORTH OF I80. MONDAY THROUGH NEXT WEDNESDAY...LONG RANGE SIGNALS SUGGEST A GENERAL BLOCKED PATTERN WITH BOOKEND RIDGES ON THE COASTS AND MID CONUS L/W TROFFINESS PERSISTING THROUGH WED. BUT THEY ALSO SUGGEST IT TO START TO MODIFY AND BREAK DOWN THE L/W TROF FEATURE AFTER TUE. THUS IN GENERAL...BELOW NORMAL TEMPS LOOK TO CONTINUE IN THE VCNTY OF THIS UPPER TROF..AS WELL AS ALMOST A DAILY THREAT OF POP UP SHOWERS AND A FEW STORMS. BETTER CHANCES OFF THOUGH TO THE SOUTHEAST OF THE DVN CWA IN VCNTY OF UPPER LOW MON INTO TUE. ..12.. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 646 PM CDT WED JUN 26 2013 ISOLATED SHOWERS AND THUNDERSTORMS OVER EASTERN IOWA ARE EXPECTED TO DISSIPATE BEFORE SUNSET...GIVING WAY TO CLEARING SKIES AND MAINLY VFR CONDITIONS OVERNIGHT. WET GROUND AND LINGERING LOW LEVEL MOISTURE MAY LEAD TO PATCHY FOG...BUT AT THIS TIME...IT APPEARS LIGHT NW WINDS WILL BE JUST STRONG ENOUGH TO KEEP VISIBILITIES ABOVE IFR THRESHOLDS. THURSDAY...LIGHT WEST TO NORTHWEST WINDS IN THE MORNING WILL INCREASE BACK TO NEAR 10 KTS BY LATE MORNING WITH CONDITIONS REMAINING VFR THROUGH THE DAY. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...SHEETS SYNOPSIS...08 SHORT TERM...08 LONG TERM...12 AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
545 PM CDT TUE JUN 25 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 343 PM CDT TUE JUN 25 2013 LATEST WATER VAPOR LOOP SHOWS A WAVE MOVING ACROSS WESTERN KANSAS. SPEED LOOP OF VISIBLE SATELLITE SHOWS SOME CIRCULATION OVER NORTH CENTRAL KANSAS WITH A CU FIELD TO ITS EAST AND NORTHEAST. SURFACE TROUGH FROM A LOW IN SOUTHWEST KANSAS NORTHEAST INTO NEBRASKA. LATEST MESO ANALYSIS CONTINUES TO SHOW DEEP MOISTURE OVER EASTERN KANSAS. DEEP MOISTURE CONVERGENCE WAS OCCURRING OVER NORTHEAST AND NORTH CENTRAL KANSAS AHEAD OF THE ABOVE MENTIONED FEATURE. EML WAS WORKING ITS WAY ACROSS SOUTH CENTRAL KANSAS THIS AFTERNOON WHERE 15 DEGREE CELSIUS AIR RESIDES. THE HRRR AND WRF SHOW SOME ISOLATED CONVECTION DEVELOPING NORTH OF I-70 LATE THIS AFTERNOON AND EVENING IN NORTH CENTRAL AND NORTHEAST KANSAS. HAVE ONLY ABOUT A 10 TO 15 PERCENT CHANCE OF A THUNDERSTORM IN THE FORECAST FOR A FEW HOURS THIS EVENING. ATMOSPHERE REMAINS UNSTABLE WITH LITTLE TO NO CONVECTIVE INHIBITION. 0-6KM SHEAR NEAR 40 KTS SO COULD SEE A SUPERCELL OR TWO DEVELOP. LOW LEVEL JET VEERS TONIGHT WITH THE DEEPER MOISTURE MOVING OFF TO THE EAST. A COLD FRONT IN THE WESTERN PLAINS WILL MOVE SOUTHEAST AND ACROSS NORTH CENTRAL AND NORTHEAST KANSAS LATER TONIGHT THROUGH MID DAY WEDNESDAY. SURFACE HIGH PRESSURE WILL MOVE IN BEHIND THE FRONT ON WEDNESDAY. TEMPERATURES WILL BE MILD AGAIN TONIGHT WITH LOWS MAINLY IN THE 70S. HIGHS ON WEDNESDAY WILL BE IN THE MID 90S IN THE NORTHEAST CORNER TO NEAR 100 IN NORTH CENTRAL KANSAS. AFTERNOON HEAT INDICES IN THE 98 TO 104 DEGREE RANGE ARE EXPECTED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 343 PM CDT TUE JUN 25 2013 THE LLVL FLOW VEERS AROUND TO THE SOUTHEAST THEN SOUTH TO SOUTHWEST WEDNESDAY NIGHT INTO THURSDAY...WARMER AIR AND DEEPER MOISTURE WILL ADVECT BACK INTO THE COUNTY WARNING AREA. A STRONG 850MB THERMAL AXIS WILL PUSH WARMER TEMPS NORTHEAST INTO THE CWA...ESPECIALLY THE SOUTHWEST COUNTIES WHERE HIGHS IN THE 100-103 RANGE SHOULD BE COMMON AS MIXING ACROSS THE AREA BY AFTERNOON DEEPENS SUBSTANTIALLY. THIS WILL NOT ONLY RAISE TEMPS...BUT AT THE SAME TIME...LOWER DEWPOINTS...MAINLY OVER THE WESTERN COUNTIES. HEAT INDICES THURSDAY WILL COMMONLY BE IN THE 100-105 RANGE. A SUBSTANTIAL EML WILL BE IN PLACE TO THE START THE AFTERNOON...BUT BY LATE IN THE DAY OVER THE NORTHERN COUNTIES...IT WILL LIKELY ERODE WITH ISOLATED THUNDERSTORMS POSSIBLE AND WILL CARRY A SLIGHT CHANCE POP. ALTHOUGH WINDS ALOFT WILL NOT BE ESPECIALLY STRONG...AN AREA OF HIGH CAPE VALUES AND INCREASING DIRECTIONAL SHEAR THROUGH 6KM WILL DEVELOP ALONG AND AHEAD OF THE BOUNDARY SLIPPING SOUTHWARD LATE IN THE DAY AND EVENING. WOULD EXPECT SOME INCREASE IN COVERAGE OF ANY LATE AFTERNOON CONVECTION. ALTHOUGH HAIL IS POSSIBLE...A DEEP LAYER OF NEARLY ADIABATIC LAPSE RATES COULD MAKE STRONG WINDS GUSTS THE PRIMARY HAZARD FOR ANY CONVECTION THAT MAY DEVELOPS. MODELS SEEM A FAIRLY GOOD AGREEMENT THAT ANY CONVECTION THAT DEVELOPS...SHOULD BE SOUTH OF THE CWA BY SUNRISE FRIDAY AS THE BOUNDARY MOVES SOUTHWARD. WILL KEEP THE HIGHEST POPS OVER THE FAR NORTHEAST/EASTERN COUNTIES. IT SHOULD ALSO MARK THE BEGINNING OF A GRADUAL DECLINE IN BOTH TEMPERATURES AND DEWPOINTS AS A LARGE SCALE UPPER TROUGH DEEPENS THROUGH THE WEEKEND OVER THE EASTERN CONUS. DEWPOINTS WILL COMMONLY BE IN THE 50S TO NEAR 60 DEGREES THROUGH THE WEEKEND. ALTHOUGH IT WILL STILL BE THE LOW TO MIDDLE 90S MOST AREAS FRIDAY...HIGHS IN THE 80S WILL BE THE RULE THROUGH THE WEEKEND INTO EARLY NEXT WEEK. WILL CARRY A SLIGHT CHANCE FOR THUNDERSTORMS OVER THE FAR NORTHEAST ON SUNDAY. ALTHOUGH CANNOT TOTALLY RULE OUT ISOLATED CONVECTION IN THE NORTHWEST FLOW REGIME OVER THE AREA...DRIER AIR OVER THE AREA AND THE LACK OF ANY CONSISTENT FORCING MECHANISM TO DEVELOP PRECIP WARRANTS KEEPING THE REMAINDER OF THE FCST DRY AT THIS POINT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 545 PM CDT TUE JUN 25 2013 LAPS ANALYSIS AND RAP PROGS SHOW THE BETTER LOW LEVEL CONVERGENCE ALONG THE SURFACE TROUGH AXIS OVER CENTRAL KS. HOWEVER THERE HAS NOT BEEN MUCH DEVELOPMENT AT ALL OF A CU FIELD IN CENTRAL KS. SO THINK THE INHIBITION TO CONVECTION IS HOLDING AND THEREFORE WILL MAINTAIN A VFR FORECAST WITHOUT ANY MENTION OF PRECIP. THE TROUGH AXIS SHOULD MOVE THROUGH THE TERMINALS LATE TONIGHT CAUSING SFC WINDS TO GRADUALLY RELAX. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...53 LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
346 PM CDT TUE JUN 25 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 343 PM CDT TUE JUN 25 2013 LATEST WATER VAPOR LOOP SHOWS A WAVE MOVING ACROSS WESTERN KANSAS. SPEED LOOP OF VISIBLE SATELLITE SHOWS SOME CIRCULATION OVER NORTH CENTRAL KANSAS WITH A CU FIELD TO ITS EAST AND NORTHEAST. SURFACE TROUGH FROM A LOW IN SOUTHWEST KANSAS NORTHEAST INTO NEBRASKA. LATEST MESO ANALYSIS CONTINUES TO SHOW DEEP MOISTURE OVER EASTERN KANSAS. DEEP MOISTURE CONVERGENCE WAS OCCURRING OVER NORTHEAST AND NORTH CENTRAL KANSAS AHEAD OF THE ABOVE MENTIONED FEATURE. EML WAS WORKING ITS WAY ACROSS SOUTH CENTRAL KANSAS THIS AFTERNOON WHERE 15 DEGREE CELSIUS AIR RESIDES. THE HRRR AND WRF SHOW SOME ISOLATED CONVECTION DEVELOPING NORTH OF I-70 LATE THIS AFTERNOON AND EVENING IN NORTH CENTRAL AND NORTHEAST KANSAS. HAVE ONLY ABOUT A 10 TO 15 PERCENT CHANCE OF A THUNDERSTORM IN THE FORECAST FOR A FEW HOURS THIS EVENING. ATMOSPHERE REMAINS UNSTABLE WITH LITTLE TO NO CONVECTIVE INHIBITION. 0-6KM SHEAR NEAR 40 KTS SO COULD SEE A SUPERCELL OR TWO DEVELOP. LOW LEVEL JET VEERS TONIGHT WITH THE DEEPER MOISTURE MOVING OFF TO THE EAST. A COLD FRONT IN THE WESTERN PLAINS WILL MOVE SOUTHEAST AND ACROSS NORTH CENTRAL AND NORTHEAST KANSAS LATER TONIGHT THROUGH MID DAY WEDNESDAY. SURFACE HIGH PRESSURE WILL MOVE IN BEHIND THE FRONT ON WEDNESDAY. TEMPERATURES WILL BE MILD AGAIN TONIGHT WITH LOWS MAINLY IN THE 70S. HIGHS ON WEDNESDAY WILL BE IN THE MID 90S IN THE NORTHEAST CORNER TO NEAR 100 IN NORTH CENTRAL KANSAS. AFTERNOON HEAT INDICES IN THE 98 TO 104 DEGREE RANGE ARE EXPECTED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 343 PM CDT TUE JUN 25 2013 THE LLVL FLOW VEERS AROUND TO THE SOUTHEAST THEN SOUTH TO SOUTHWEST WEDNESDAY NIGHT INTO THURSDAY...WARMER AIR AND DEEPER MOISTURE WILL ADVECT BACK INTO THE COUNTY WARNING AREA. A STRONG 850MB THERMAL AXIS WILL PUSH WARMER TEMPS NORTHEAST INTO THE CWA...ESPECIALLY THE SOUTHWEST COUNTIES WHERE HIGHS IN THE 100-103 RANGE SHOULD BE COMMON AS MIXING ACROSS THE AREA BY AFTERNOON DEEPENS SUBSTANTIALLY. THIS WILL NOT ONLY RAISE TEMPS...BUT AT THE SAME TIME...LOWER DEWPOINTS...MAINLY OVER THE WESTERN COUNTIES. HEAT INDICES THURSDAY WILL COMMONLY BE IN THE 100-105 RANGE. A SUBSTANTIAL EML WILL BE IN PLACE TO THE START THE AFTERNOON...BUT BY LATE IN THE DAY OVER THE NORTHERN COUNTIES...IT WILL LIKELY ERODE WITH ISOLATED THUNDERSTORMS POSSIBLE AND WILL CARRY A SLIGHT CHANCE POP. ALTHOUGH WINDS ALOFT WILL NOT BE ESPECIALLY STRONG...AN AREA OF HIGH CAPE VALUES AND INCREASING DIRECTIONAL SHEAR THROUGH 6KM WILL DEVELOP ALONG AND AHEAD OF THE BOUNDARY SLIPPING SOUTHWARD LATE IN THE DAY AND EVENING. WOULD EXPECT SOME INCREASE IN COVERAGE OF ANY LATE AFTERNOON CONVECTION. ALTHOUGH HAIL IS POSSIBLE...A DEEP LAYER OF NEARLY ADIABATIC LAPSE RATES COULD MAKE STRONG WINDS GUSTS THE PRIMARY HAZARD FOR ANY CONVECTION THAT MAY DEVELOPS. MODELS SEEM A FAIRLY GOOD AGREEMENT THAT ANY CONVECTION THAT DEVELOPS...SHOULD BE SOUTH OF THE CWA BY SUNRISE FRIDAY AS THE BOUNDARY MOVES SOUTHWARD. WILL KEEP THE HIGHEST POPS OVER THE FAR NORTHEAST/EASTERN COUNTIES. IT SHOULD ALSO MARK THE BEGINNING OF A GRADUAL DECLINE IN BOTH TEMPERATURES AND DEWPOINTS AS A LARGE SCALE UPPER TROUGH DEEPENS THROUGH THE WEEKEND OVER THE EASTERN CONUS. DEWPOINTS WILL COMMONLY BE IN THE 50S TO NEAR 60 DEGREES THROUGH THE WEEKEND. ALTHOUGH IT WILL STILL BE THE LOW TO MIDDLE 90S MOST AREAS FRIDAY...HIGHS IN THE 80S WILL BE THE RULE THROUGH THE WEEKEND INTO EARLY NEXT WEEK. WILL CARRY A SLIGHT CHANCE FOR THUNDERSTORMS OVER THE FAR NORTHEAST ON SUNDAY. ALTHOUGH CANNOT TOTALLY RULE OUT ISOLATED CONVECTION IN THE NORTHWEST FLOW REGIME OVER THE AREA...DRIER AIR OVER THE AREA AND THE LACK OF ANY CONSISTENT FORCING MECHANISM TO DEVELOP PRECIP WARRANTS KEEPING THE REMAINDER OF THE FCST DRY AT THIS POINT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1249 PM CDT TUE JUN 25 2013 SOUTH WINDS WILL INCREASE TO AROUND 18 KTS WITH GUSTS AS HIGH AS 30 KTS THROUGH 02Z. SOUTH TO SOUTHWEST WINDS NEAR 10 KTS TONIGHT. A COLD FRONT WILL MOVE THROUGH THE TERMINALS IN THE 11Z-14Z TIME FRAME WEDNESDAY. SOME ISOLATED CONVECTION IS POSSIBLE THROUGH 06Z BUT CONFIDENCE NOT HIGH ENOUGH TO ADD VCTS ATTM. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...63 AVIATION...53
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1137 PM CDT MON JUN 24 2013 ...UPDATED FOR AVIATION... .SYNOPSIS... ISSUED AT 353 PM CDT MON JUN 24 2013 A FAIRLY STRONG SHORTWAVE TROUGH BY LATE JUNE STANDARDS WAS APPROACHING THE SOUTHERN AND CENTRAL HIGH PLAINS THIS AFTERNOON. AHEAD OF THIS FEATURE, STRONG SURFACE TROUGH HAD DEVELOPED OVER THE HIGH PLAINS, WITH STRONG SOUTHERLY WINDS ACROSS SOUTHWEST KANSAS. ELEVATED CONVECTION IN ADVANCE OF THIS SYSTEM DEVELOPED THIS MORNING EAST OF DODGE CITY AND THEN MOVED EAST AND WEAKENED. ANOTHER BATCH OF ELEVATED CONVECTION DEVELOPED WEST OF A SURFACE DRYLINE IN SOUTHEAST COLORADO AND MOVED INTO FAR SOUTHWEST KANSAS THIS AFTERNOON. SURFACE BASED CONVECTION HAD NOT YET DEVELOPED AS OF 3 PM. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM CDT MON JUN 24 2013 THE SHORT RANGE HRRR DOES INDICATE STORMS DEVELOPING IN THE TEXAS AND OKLAHOMA PANHANDLES THIS AFTERNOON AS UPPER LEVEL FORCING AIDS IN LOW LEVEL CONVERGENCE ALONG THE DRYLINE. GIVEN THE FAIRLY STRONG MID LEVEL FLOW FROM THE SOUTHWEST, THIS CONVECTION SHOULD MOVE NORTHEASTWARD FAIRLY RAPIDLY INTO SOUTHWEST KANSAS THIS EVENING. SURFACE BASED CAPE VALUES WERE APPROACHING 3000 J/KG FROM THE TEXAS PANHANDLE INTO SOUTHWEST KANSAS AHEAD OF THE DRYLINE. 0-6 KM BULK SHEAR WAS APPROACHING 40 KTS IN THIS SAME AREA, BUT LOW LEVEL SHEAR WAS VERY WEAK. GIVEN THE EXPECTED HIGH DEWPOINT DEPRESSIONS AND RESULTANT HIGH CLOUD BASES, THE STORMS MAY DEVELOP QUITE A BIT OF OUTFLOW, AND THIS MAY LIMIT THE SEVERITY AS FAR AS HAIL SIZE IS CONCERNED (SINCE THE STORMS MAY NOT REMAIN AS SUPERCELL STRUCTURES AS LONG). BUT HAIL AS LARGE AS GOLFBALLS IS POSSIBLE WITH THE STRONGEST STORMS. IT IS UNCLEAR HOW ORGANIZED THE STORMS WILL BE AND HOW WIDESPREAD AND HEAVY THE RESULTANT RAINFALL WOULD BE. BUT STORM CHANCES WERE INCREASED TO 30-40% FOR PARTS OF SOUTHWEST KANSAS INCLUDING DODGE CITY, JETMORE AND LARNED GIVEN THE SIGNIFICANT FORCING AND SURFACE BASED CAPE. AFTER THE AFOREMENTIONED SHORTWAVE TROUGH PASSES TONIGHT AND WITH THE LOSS OF DAYTIME HEATING, STORM CHANCES WILL DIMINISH RAPIDLY BY LATE EVENING. THE LOW LEVEL WINDS WILL BEGIN TO VEER AS WELL AND THIS WILL RESULT IN THE AXIS OF DEEP MOISTURE SHIFTING EASTWARD. SOUTHWEST WINDS AT 15 KTS EVEN LATE TONIGHT WILL PREVENT TEMPERATURES FROM DROPPING BELOW THE LOWER 70S AT DODGE CITY, HAYS AND PRATT, WITH ONLY SLIGHTLY COOLER READINGS NEAR THE COLORADO BORDER. BEHIND THE SHORTWAVE TROUGH, A WEAK COLD FRONT WILL PROGRESS INTO CENTRAL KANSAS TUESDAY AFTERNOON, WITH A TRAILING DRYLINE EAST OF DODGE CITY AND INTO THE PANHANDLES. VERY HOT TEMPERATURES FROM 103 TO 106F ARE EXPECTED IMMEDIATELY BEHIND THE DRYLINE WHERE THE LOW LEVEL AIR HAS MOVED DOWNSLOPE AND WARMED ADIABATICALLY. ONLY SLIGHTLY COOLER AIR CAN BE EXPECTED IN FAR WESTERN KANSAS ON THE HIGHER TERRAIN, AND BEHIND THE WEAK COLD FRONT FROM WAKEENEY TO DIGHTON. THUNDERSTORMS ARE NOT EXPECTED TUESDAY AFTERNOON GIVEN THE LACK OF FORCING IN THE WAKE OF THE SHORTWAVE TROUGH AND SINCE THE LOW LEVEL MOIST AXIS WILL HAVE SHIFTED FURTHER EAST BY THE TIME OF PEAK HEATING. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 336 PM CDT MON JUN 24 2013 ZONAL FLOW ALOFT WILL BE IN PLACE OVER THE LOWER 48 STATES AT THE BEGINNING OF THE EXTENDED PERIOD. A SHORTWAVE TROUGH THAT IS NOW MOVING THROUGH THE GREAT BASIN AND DESERT SOUTHWEST WILL BE EXITING THE NORTHERN AND CENTRAL PLAINS TUESDAY EVENING. THIS SYSTEM WILL BRING A WEAK FRONTAL BOUNDARY SOUTH ACROSS WESTERN KANSAS IN ITS WAKE LATE TUESDAY AFTERNOON AND EVENING. PRECIPITATION CHANCES LOOK FAIRLY SMALL GIVEN THE LACK OF UPPER SUPPORT AND A FAIRLY DRY AIRMASS. THROUGH THE MIDDLE PART OF THE WEEK, 500 MILLIBAR HEIGHTS WILL BE BUILDING OVER THE WESTERN AND CENTRAL PART OF THE COUNTRY. WITH INCREASING THICKNESS VALUES OVER WESTERN KANSAS WE SHOULD SEE DAYTIME HIGH TEMPERATURES WARMING BACK UP TO AROUND OR ABOVE 100 DEGREES ESPECIALLY BY THURSDAY. THE UPPER RIDGE BECOMES MORE AMPLIFIED OVER WESTERN NORTH AMERICA TOWARD THE UPCOMING WEEKEND WITH UPPER LEVEL FLOW BECOMING MORE NORTHWESTERLY OVER THE CENTRAL PLAINS. A WEAK FRONTAL BOUNDARY IS FORECAST TO MOVE SOUTH THROUGH THE CENTRAL HIGH PLAINS EARLY FRIDAY WITH EASTERLY UPSLOPE FLOW SETTING UP INTO THE EASTERN SLOPES OF THE ROCKIES. AFTERNOON THUNDERSTORMS SHOULD DEVELOP OFF THE FRONT RANGE. GIVEN THE UPPER LEVEL FLOW, SOME OF THESE COULD MOVE INTO FAR WESTERN KANSAS FRIDAY EVENING. THE UPPER LEVEL FLOW OVER THE CENTRAL PART OF THE COUNTRY BECOMES EVEN MORE MERIDIONAL THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE MEDIUM RANGE MODELS HAVE ALL BEEN TRENDING IN THIS DIRECTION THROUGH THE PAST FEW RUNS. THINK THAT THE CURRENT WEEK TWO OUTLOOK SHOULD BE TRENDED BACK TO AT LEAST NEAR NORMAL TEMPERATURES FOR NOW BUT BASED ON FORECAST TEMPERATURES, WE COULD BE EVEN COOLER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1133 PM CDT MON JUN 24 2013 EXPECT VFR CONDITIONS THROUGH THE PERIOD. A DRYLINE TROUGH WILL MOVE ACROSS WESTERN KANSAS AFTER 12Z WITH SOUTH WINDS SHIFTING TO THE SOUTH BUT DECREASING IN THE TROUGH AXIS. && .PRELIMINARY POINT TEMPS/POPS... DDC 73 105 69 101 / 10 0 0 0 GCK 72 104 65 101 / 10 0 0 0 EHA 70 103 66 101 / 10 0 0 0 LBL 74 105 68 104 / 10 0 0 0 HYS 74 104 70 101 / 20 0 0 0 P28 74 100 74 101 / 20 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FINCH SHORT TERM...FINCH LONG TERM...GERARD AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS PADUCAH KY
326 PM CDT TUE JUN 25 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 325 PM CDT TUE JUN 25 2013 A FEW ISOLATED THUNDERSTORMS WILL BE POSSIBLE THROUGH SUNSET OVER THE ENTIRE AREA...BUT THE PRIMARY FOCUS LOOKS TO BE ALONG THE NORTHWEST PERIPHERY OF THE AREA AND FARTHER NORTH LATE THIS AFTERNOON. ANY ACTIVITY TO OUR NORTH WOULD LIKELY MOVE EASTWARD...BUT COULD BUILD SOUTHWARD INTO OUR FAR NORTH OR NORTHEAST COUNTIES THIS EVENING. LEFT A SLIGHT CHANCE THROUGH THE EVENING ALONG THE NORTHEAST PERIPHERY OF THE AREA. DUE TO THE EXTREME INSTABILITY ACROSS THE AREA...A FEW STORMS COULD BRIEFLY PULSE UP TO PRODUCE MARGINALLY SEVERE HAIL OR WINDS...BUT THE PRIMARY CONCERN WILL BE LOCALLY HEAVY RAINFALL. THE LATEST HRRR AND 12Z WRF RUNS INDICATE THAT AN MCS MAY BE APPROACHING THE AREA FROM THE NORTHWEST BY 12Z. THE FLOW ALOFT WILL BEGIN TO SHIFT TO THE NORTHWEST TONIGHT...SO THIS GENERAL SYSTEM MOVEMENT IS LIKELY. THE MODELS GENERALLY WEAKEN THE SYSTEM AS IT ENCOUNTERS THE WEAKER FLOW OVER OUR AREA. IT IS NOT CERTAIN WHETHER THE ACTIVE CONVECTION WILL REACH THE AREA...BUT AN OUTFLOW BOUNDARY WILL AT LEAST GET VERY CLOSE TO THE AREA. TWO THINGS TO CONSIDER HERE ARE THE POTENTIAL FOR THE OLD COLD POOL TO SURGE INTO THE AREA...MUDDLING UP THE OTHERWISE HOT...HUMID AND BREEZY DAY THAT IS CURRENTLY FORECAST...AND THE POTENTIAL FOR THE OUTFLOW TO FOCUS NEW THUNDERSTORM DEVELOPMENT OR JUST RE-INTENSIFY OVER OUR AREA DURING THE DAY. THE MODELS HAVE CONSISTENTLY INDICATED INCREASING SHEAR THROUGH THE DAY FROM THE NORTHWEST...AND DEVELOPED RATHER EXTREME INSTABILITY SOUTH OF ANY OUTFLOWS IN THE AFTERNOON. THEREFORE...WOULD NOT EXPECT ANY CONVECTION THROUGH THE MORNING TO POSE MORE THAN A HEAVY RAIN THREAT. HOWEVER...NO MATTER THE MEANS OF GENERATION...STORMS LATER INTO THE AFTERNOON AND THROUGH THE EVENING WILL LIKELY POSE A LARGE HAIL AND DAMAGING WIND THREAT. THE STORMS WILL MOVE TO THE SOUTHEAST...AND ANY RIGHT MOVING STORMS MAY MOVE DUE SOUTH OR EVEN SOUTHWEST. IN THE ABSENCE OF A MAJOR COLD POOL INVASION EARLY WEDNESDAY...A LAKE WIND ADVISORY AND POSSIBLY A HEAT ADVISORY WILL BE NEEDED THROUGH THE DAY. WILL NOT ISSUE EITHER AT THIS TIME DUE TO THE UNCERTAINTIES IN THE OVERNIGHT CONVECTIVE FORECAST. PRESUMABLY IT WILL BE A CLEARER DECISION FOR THE MIDNIGHT SHIFT. AS FOR TEMPERATURES...WENT ON THE MILD SIDE OF MOST GUIDANCE FOR TONIGHT...AND EVEN WEDNESDAY NIGHT GIVEN NO SIGN OF SIGNIFICANT DRY ADVECTION INTO THE AREA. HIGHS ON WEDNESDAY ARE LIKELY TO BE A REAL PAIN. TRIED TO KEEP IT HOT IN THE WEST AND COOL IT DOWN A BIT IN THE EAST CLOSER TO ANY ALL DAY OUTFLOW/CONVECTION POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 325 PM CDT TUE JUN 25 2013 THIS EXTENDED PERIOD ESSENTIALLY STARTS FOLLOWING THE PASSAGE OF THE CLOSED LOW THROUGH THE GREAT LAKES AND THE APPROACH OF THE WESTERN U.S. RIDGE. THE WFO PAH AREA IS POISED ON THE SOUTHERN EDGE OF THE BAROCLINIC ZONE EMBEDDED IN FAST NORTHWEST FLOW. THE PENNYRILE REGION OF WEST KENTUCKY AND SOUTHWEST INDIANA ARE ON THE WEST EDGE OF THE FOCUSED LIFT/STRETCHING OF PARCELS...SO KEPT A SMALL MENTION OF THUNDERSTORMS IN THAT AREA. THE SHORT RANGE ENSEMBLE /SREF/ SUGGESTS THAT THERE WILL BE A WEAK BOUNDARY INTERACTION ALONG THE SOUTHERN SECTIONS OF THE WFO PAH FORECAST AREA INTO THURSDAY NIGHT /MAINLY OVER SOUTHEAST MISSOURI AND WEST KENTUCKY/ TANGENTIAL TO THE FASTER NORTHWEST FLOW. WITH THIS IN MIND...KEPT A SMALL CHANCE OF THUNDERSTORMS ADJACENT TO THE BOUNDARY. FROM FRIDAY INTO FRIDAY EVENING...ALTHOUGH THE SURFACE FLOW IS NORTHWEST...THERE IS SOME DIFFERENTIAL SPEED SHEAR AND LOW LEVEL THERMAL GRADIENT ALONG THE SOUTHERN EDGE OF THE WESTERLIES...WITH MEAGER LOW/MID LEVEL MOISTURE IN THE WFO PAH FORECAST AREA. AT THIS TIME...NOT REAL CONFIDENT THAT THERE WILL BE MUCH GREATER THAN WIDELY SCATTERED COVERAGE FOR CONVECTION...SO POPS/WEATHER ARE A LITTLE LOWER THAN SURROUNDING NWS OFFICES AT THIS TIME. THE GFS/GFS ENSEMBLE TAKES THE PREVIOUSLY MENTIONED GREAT LAKES LOW AND ROTATE ANOTHER SHORTWAVE AROUND THE LOW DOWN THROUGH THE UPPER MIDWEST ON SATURDAY. WITH THIS NEXT SHORTWAVE...THERE IS SOME SUPPORT FOR ELEVATED CONVECTION BY NEXT SUNDAY. FROM MONDAY INTO TUESDAY...AS THE LOW SHARPENS OVER THE WFO PAH FORECAST AREA...INTRODUCED A CHANCE FOR CONVECTION ALONG THE EASTERN LIMB OF THE SHARPENING TROUGH...MAINLY OVER THE PENNYRILE REGION OF WEST KENTUCKY AND SOUTHWEST INDIANA. THERE WOULD BE A SLIGHT TEMPORAL SHIFT WESTWARD AS IMPULSES WORK THROUGH THE BASE OF THE TROUGH. TEMPERATURE-WISE...THERE WILL BE SOME VARIANCE AS THE THE SOUTHERN LIMIT OF THE ANTECEDENT CONVECTION WEDNESDAY AND WEDNESDAY NIGHT...ALONG WITH THE POSITION OF THE EFFECTIVE BOUNDARY OVER THE WFO PAH FORECAST AREA. AT THIS TIME...LEANED TOWARD THE SREF SOLUTION. THIS WILL PLACE A SHARP THERMAL GRADIENT OVER SOUTHEAST MISSOURI...WITH HIGH TEMPERATURES EXPECTED TO TOP OUT INTO THE UPPER 90S...WITH WIDESPREAD HEAT INDEX VALUES BETWEEN 100 AND 105 DEGREES ALONG AND WEST OF THE MISSISSIPPI RIVER. BEYOND THURSDAY... TEMPERATURES SHOULD REMAIN AT OR BELOW NORMAL WITH HIGHS FALLING BACK INTO THE 80S. && .AVIATION... ISSUED AT 103 PM CDT TUE JUN 25 2013 KEPT THE 18Z TAFS REAL SIMPLE. DID NOT INCLUDE ANY TS THIS AFTERNOON...AS ISOLATED COVERAGE IS NOT LIKELY TO DIRECTLY IMPACT ANY OF THE TERMINALS. NICE CU FIELD AND SOUTHWEST WINDS GUSTING INTO THE TEENS WILL CONTINUE THROUGH THE AFTERNOON. THE PRESSURE GRADIENT WILL REMAIN TIGHT ENOUGH TO SUPPORT A SOUTHERLY BREEZE THROUGHOUT THE AREA TONIGHT. AS STATED IN THE UPDATE SECTION THE POTENTIAL EXISTS FOR CONVECTION TO MOVE SOUTHWARD INTO THE AREA OVERNIGHT INTO WEDNESDAY MORNING. HOWEVER...CONFIDENCE IS TOO LOW IN THE TIMING...LOCATION AND DIRECTION OF MOVEMENT OF ANY SUCH COMPLEX TO MENTION IN THE TAFS AT THIS TIME. NICE CU FIELD AND GUSTIER SOUTHWEST WINDS ARE EXPECTED TO DEVELOP MID TO LATE WEDNESDAY MORNING...AND TS POTENTIAL WILL BE INCREASING THROUGH THE LATE MORNING...ESPECIALLY IN THE NORTHEAST. SO...MENTIONED PROB30 FOR VFR TS IN THE NORTHEAST IN THE LAST FEW HOURS OF THE TAF PERIOD. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...DRS LONG TERM...SMITH AVIATION...DRS
AREA FORECAST DISCUSSION
NWS GRAY ME
1123 AM EDT TUE JUN 25 2013 .SYNOPSIS... HOT AND HUMID AIR CONTINUES TO BE PUSHED NORTH INTO NEW ENGLAND AS SOUTHWEST FLOW PERSISTS OVER THE AREA. THE THREAT FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL ALSO CONTINUE. BY THURSDAY AND FRIDAY THERE IS A CHANCE FOR A MORE CONSISTENT RAIN AS WEAK LOW PRESSURE DEVELOPS TO OUR WEST AND LIFTS NORTHEAST INTO QUEBEC. THIS WILL ALSO SHIFT THE WINDS MORE ONSHORE...WITH COOLER TEMPERATURES AT THE END OF THE WEEK...ALTHOUGH THE HUMIDITY WILL NOT DROP OFF THAT MUCH. WE WILL SWITCH BACK TO A SOUTHERLY FLOW FOR THE WEEKEND...WITH WARMER AND CONTINUED HUMID CONDITIONS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 11 AM...STILL LOOKING FOR THE DEVELOPMENT OF SEVERE STORMS THIS AFTERNOON. 12Z KGYX RAOB SHOWS G0OD CAPPING...BUT THIS SHOULD WEAKEN EARLY THIS AFTERNOON...AS WEAK 500MB WAVE TRACKS JUST TO THE N OF THE CWA...AND 500MB HEIGHTS FALL. ALSO...WILL SEE UVV DEVELOP NEAR JET ENTRY REGION PASSING OVER NRN ZONES. EXPECTING SCT-BKN LINE OF STORMS TOP DEVELOP TOUR WEST AND TRACK E ACROSS THE AREA MID-LATE AFTERNOON...PRODUCING MAINLY STRONG WINDS. COULD SEE SOME PULSE TYPE STORMS AHEAD THIS LINE AS WELL. HEAVY RAIN IS ANOTHER PROBLEM AS PWATS ARE FORECAST TO INCREASE TO 1.5-1.8 LATER TODAY. PREVIOUSLY...LATEST HRRR RUN CONTINUES TO INDICATE CONVECTIVE INITIATION BEGINNING AROUND 18Z OVER FAR NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA. THIS IS IN RESPONSE TO SHORT WAVE RACING ACROSS SOUTHERN CANADA. WIND FIELDS WILL BE INCREASING (AND UNIDIRECTIONAL) WITH THIS FEATURE. WITH STEEP LOW LEVEL LAPSE RATES AND HIGH SURFACE DEW POINTS IN PLACE...CONVECTION TODAY WILL BE MORE ORGANIZED THAN YESTERDAY AS THE WIND MAX APPROACHES FROM THE NORTHWEST. DAMAGING STRAIGHT LINE WINDS ARE POSSIBLE IN ISOLATED STORMS...WITH LARGE HAIL POSSIBLE IN ANY OF THE STRONGER STORMS AS CAPE VALUES RAPIDLY CLIMB WITH GOOD SOLAR HEATING TODAY. HAVE ENHANCED WORDING IN THE GRIDS. PRECIPITABLE WATER VALUES REMAIN VERY HIGH. SOME OF THE SHOWERS AND STORMS MAY DROP VERY HEAVY RAIN IN A SHORT PERIOD OF TIME. STORMS WILL BE RELATIVELY FAST MOVING...BUT TRAINING OF SHOWERS WILL NEED TO BE MONITORED. AN AIR QUALITY ALERT WILL REMAIN IN EFFECT FOR TODAY...UNTIL 11 PM. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... WITH LOW LEVEL MOISTURE IN PLACE...AFTER AFTERNOON AND EVENING RAINS...PATCHY FOG WILL DEVELOP ONCE AGAIN ACROSS THE REGION TONIGHT. USED A BLEND OF MAV/MET MOS FOR OVERNIGHT MIN TEMPERATURES. MORE SHOWERS AND STORMS ARE POSSIBLE WEDNESDAY AFTERNOON AS A BACKDOOR COLD FRONT MOVES SOUTH ACROSS MAINE AND NEW HAMPSHIRE. SOME OF THESE STORMS MAY BE LOCALLY STRONG AS WELL. READINGS OVER SOUTHERN NEW HAMPSHIRE WILL SHOOT UP QUICKLY AHEAD OF THE SURFACE COLD FRONT...SO A HEAT WAVE (3 CONSECUTIVE DAYS AT OR ABOVE 90 DEGREES) IS STILL POSSIBLE OVER THIS REGION. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE MODELS ARE IN DECENT AGREEMENT WELL INTO NEXT WEEK ON EVOLVING LONGWAVE PATTERN. A SERIES OF SHORTWAVES RIDING OVER THE TOP OF THE WESTERN CONUS RIDGE WILL CARVE OUT A DEEP TROUGH ACROSS THE EAST BY THE UPCOMING WEEKEND. THE OVERALL THEME WILL BE WARM...HUMID...AND WET FOR THE FORECAST PERIOD. IN THE DAILIES...LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES ON THURSDAY THEN SLOW DOWN AND LINGER ACROSS THE NORTHEAST THROUGH EARLY NEXT WEEK PRODUCING WARM, HUMID, AND WET WEATHER ACROSS THE AREA. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... SHORT TERM... MORNING FOG IN SHELTERED VALLEYS WILL LIFT EARLY THIS MORNING. THIS WILL ALLOW FOR SUNNY AND HUMID CONDITIONS...WITH THE DEVELOPMENT OF MORE SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED. PATCHY FOG TO DEVELOP AGAIN TONIGHT WITH LOCAL IFR CONDITIONS...FOLLOWED BY MORE SHOWERS AND STORMS WEDNESDAY AFTERNOON. LONG TERM... THU - SAT...AREAS OF MVFR LIKELY IN SHOWERS AND THUNDERSTORMS. && .MARINE... SHORT TERM... SOUTHWEST FLOW CONTINUES THROUGH TUESDAY BUT SHOULD KEEP CONDITIONS BELOW ADVISORY LEVELS. LONG TERM... FRI - SAT...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...CEMPA SHORT TERM... LONG TERM... AVIATION... MARINE...
AREA FORECAST DISCUSSION
NWS CARIBOU ME
956 AM EDT TUE JUN 25 2013 .SYNOPSIS... STRONG TO POSSIBLY SEVERE THUNDERSTORMS ARE EXPECTED TODAY AS A FRONTAL BOUNDARY SAGS SOUTHWARD ACROSS THE AREA. UNSETTLED CONDITIONS WILL PERSIST THROUGH THE REMAINDER OF THE WEEK AND UPCOMING WEEKEND AS A BROAD AND SLOW MOVING LOW PRESSURE SYSTEM FROM THE GREAT LAKES MOVES EASTWARD. && .NEAR TERM /THROUGH TONIGHT/... 930AM UPDATE... CONVECTIVE ACTIVITY REMAINS ON TRACK TO DEVELOP EARLY TO MID AFTERNOON COINCIDENT WITH AFTERNOON HEATING IN A VERY HUMID AIR MASS. THIS HEATING ALSO COINCIDE WITH THE ARRIVAL OF AN UPPER TROUGH AND THE RIGHT ENTRANCE REGION OF AN UPPER JET. THESE FACTORS WILL CONTRIBUTE TO INSTABILITY SUFFICIENT FOR STRONG TO SEVERE THUNDERSTORMS WITH DAMAGING WINDS...HAIL AND HEAVY RAIN. THUNDERSTORMS WILL WIND DOWN LATER IN THE EVENING. UPDATE 0520L: FEW INITIAL SHOWERS/TSTM INTO XTRM NRN AND WRN MAINE ATTM... ADJUSTED POPS/HRLY TEMPS TO BETTER FIT CURRENT AND EXPECTED TRENDS NXT FEW HRS... QUIET ACROSS THE FA FOR NOW AS WEAKENING BAND OF SHOWERS HAS EXITED OUR SERN AREAS WHILE ANOTHER CLUSTER OF SHOWERS AND TSTMS IS NOTED NW-N OF THE FA ALONG AND JUST W OF THE ST LAWRENCE... NR STATIONARY FRONTAL BNDRY N OF THE REGION XTNDG WNW-ESE FROM JAMES BAY ACROSS THE GASPE AND INTO THE GULF OF THE ST LAWRENCE. SEVERAL WEAK LOWS CONT TO SLIDE ESEWRD ALONG THIS BNDRY W/ THE STRONGEST OF THESE NR THE SERN TIP OF JAMES BAY ATTM. MODELS IN FAIRLY GOOD AGREEMENT AND ALLOW THIS SFC LOW NR JAMES BAY TO DROP SEWRD ALONG THIS FRONTAL BNDRY W/ THE FRONTAL BNDRY SAGGING SWRD ACROSS THE AREA FROM LATE TDY THRU TNGT. VRY WARM/HUMID AND UNSTABLE AIR IN PLACE ACROSS THE AREA S OF THIS BNDRY W/ SBCAPES FCST FROM 1000-2500 J/KG AND THIS WILL COMBINE W/ STRONG SFC AND UPPER DYNAMICS AS THIS FRONTAL BNDRY AND LOW PRES SAG SEWRD TOWARDS THE AREA LATER TDY TO PRODUCE THE THREAT OF STRONG TO PSBLY SEVERE TSTMS ACROSS THE AREA. CURRENTLY THE SPC HAS ALL BUT OUR DOWNEAST AREAS IN A SLIGHT RISK FOR SVR W/ DAMAGING WNDS THE PRIMARY THREAT. INITIAL ACTIVITY NW-N OF THE AREA IS FCST BY THE SHORTER TERM MODEL GUIDANCE LIKE THE HRRR AND RUC TO WEAKEN AND DISSIPATE AS IT REACHES OUR FAR NRN AREAS ERLY THIS AM BUT NOT SURE ABOUT THIS... IN ANY CASE...APPEARS STRONGER ACTIVITY WILL DVLP LATER THIS AM THRU THE AFTN HRS W/ HGHST POPS ACROSS THE N AND E CENTRAL AREAS IN TO THE EVE HRS W/ LOWEST POPS FAR SW. WILL CARRY MENTION OF SVR ALONG W/ ENHANCED WORDING FOR HVY RAIN/DAMAGING WNDS AND SMALL HAIL... FOR TNGT...GUIDANCE SUGGESTS THIS BNDRY WILL BE JUST S AND W OF THE FA BY ERLY WED W/ WEAK LOW PRES CNTRS OVR ERN NS...SRN MAINE AND SWRN QUEBEC. HIGH PRES W/ SOME DRIER AIR MAY TRY TO NUDE INTO FAR NERN AREAS BY LATE TNGT/ERLY WED... EXPECT ANOTHER WARM AND MUGGY DAY TDY W/ HIGH TEMPS LARGELY DEPENDENT ON CLD CVR. THINKING THERE WILL BE SOME SUN N AND NE W/ MORE PREVALENT SUNSHINE S AND W. WILL ADVERTISE HIGHS INTO THE LOWER 80S N W/ NR 90 PSBL SRN AREAS AWAY FROM THE COAST. ANOTHER WARM AND MUGGY NGT TNGT ACROSS RN AND WRN AREAS W/ SOME COOLER AND DRIER AIR LIKELY WORKING INTO NERN AREAS. PLENTY OF LOW LEVEL MOISTURE AND RATHER LGT WNDS SUGGESTS THE THREAT OF FOG TNGT ACROSS MUCH OF THE REGION... && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AN H5 UPPER LOW DEEPENS ACROSS THE GREAT LAKES REGION DURING THIS TIME FRAME. THIS WILL ALLOW AMPLE MOISTURE TO MOVE INTO NORTHERN NEW ENGLAND. EXPECT PERIODS OF SHOWERS BOTH DAYS. HIGHS WILL BE NEAR NORMAL ON WEDNESDAY AND MUCH BELOW NORMAL ON THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AN H5 UPPER LOW SLOWLY PROGRESSES INTO THE NORTHEAST U.S. LATE THIS WEEK AND THEN LIFTS INTO QUEBEC THIS WEEKEND. THIS ALLOWS THE DAMP WEATHER PATTERN TO PERSIST. THURSDAY NIGHT AND FRIDAY ARE FORECAST TO BE PARTICULARLY WET WITH PERIODS OF RAIN. TEMPERATURES WILL GRADUALLY WARM BACK TO SEASONAL LEVELS BY THE WEEKEND. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... NEAR TERM: PATCHY FOG ERLY THIS AM MAY RESULT IN SOME MVFR TO IFR CONDS UP UNTIL OR SHORTLY AFTER SUNRISE. MAINLY VFR CONDS ARE THEN EXPECTED OUTSIDE OF ANY SHOWERS/TSTMS W/ MVFR/IFR DURING THIS ACTIVITY. PATCHY TO AREAS OF FOG EXPECTED AGAIN TNGT ALONG W/ A THREAT OF SHOWERS MAINLY ACROSS THE SRN HALF OF THE FA. SHORT TERM: MVFR AND POSSIBLY IFR CIGS AND VSBYS ARE EXPECTED AT TAF SITES WITH SHOWERS...RAIN AND FOG. && .MARINE... NEAR TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THRU TONIGHT. VISIBILITIES COULD BE REDUCED IN PATCHY FOG TODAY...THEN IN AREAS OF FOG AND ANY SHOWERS/THUNDERSTORMS LATER TODAY AND TONIGHT. SHORT TERM: NO HEADLINES ARE FORECAST. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...KHW/MCW SHORT TERM...OKULSKI LONG TERM...OKULSKI AVIATION...KHW/MCW/OKULSKI MARINE...KHW/MCW/OKULSKI
AREA FORECAST DISCUSSION
NWS GRAY ME
655 AM EDT TUE JUN 25 2013 .SYNOPSIS... HOT AND HUMID AIR CONTINUES TO BE PUSHED NORTH INTO NEW ENGLAND AS SOUTHWEST FLOW PERSISTS OVER THE AREA. THE THREAT FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL ALSO CONTINUE. BY THURSDAY AND FRIDAY THERE IS A CHANCE FOR A MORE CONSISTENT RAIN AS WEAK LOW PRESSURE DEVELOPS TO OUR WEST AND LIFTS NORTHEAST INTO QUEBEC. THIS WILL ALSO SHIFT THE WINDS MORE ONSHORE...WITH COOLER TEMPERATURES AT THE END OF THE WEEK...ALTHOUGH HUMIDITY`S WILL NOT DROP OFF THAT MUCH. WE WILL SWITCH BACK TO A SOUTHERLY FLOW FOR THE WEEKEND...WITH WARMER AND CONTINUED HUMID CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... HAVE MADE TWEAKS TO THE GRIDS BASED ON LATEST SATELLITE IMAGES AND CURRENT TEMPERATURE AND DEW POINTS. PARTLY TO MOSTLY SUNNY CONDITIONS WILL CONTINUE UNTIL SHOWERS AND THUNDERSTORMS DEVELOP DURING THE AFTERNOON HOURS. PREV DISC... "SUPERMOON" TIDES REACHED 12 FEET IN PORTLAND EARLY THIS MORNING... LATEST HRRR RUN CONTINUES TO INDICATE CONVECTIVE INITIATION BEGINNING AROUND 18Z OVER FAR NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA. THIS IS IN RESPONSE TO SHORT WAVE RACING ACROSS SOUTHERN CANADA. WIND FIELDS WILL BE INCREASING (AND UNIDIRECTIONAL) WITH THIS FEATURE. WITH STEEP LOW LEVEL LAPSE RATES AND HIGH SURFACE DEW POINTS IN PLACE...CONVECTION TODAY WILL BE MORE ORGANIZED THAN YESTERDAY AS THE WIND MAX APPROACHES FROM THE NORTHWEST. DAMAGING STRAIGHT LINE WINDS ARE POSSIBLE IN ISOLATED STORMS...WITH LARGE HAIL POSSIBLE IN ANY OF THE STRONGER STORMS AS CAPE VALUES RAPIDLY CLIMB WITH GOOD SOLAR HEATING TODAY. HAVE ENHANCED WORDING IN THE GRIDS. PRECIPITABLE WATER VALUES REMAIN VERY HIGH. SOME OF THE SHOWERS AND STORMS MAY DROP VERY HEAVY RAIN IN A SHORT PERIOD OF TIME. STORMS WILL BE RELATIVELY FAST MOVING...BUT TRAINING OF SHOWERS WILL NEED TO BE MONITORED. AN AIR QUALITY ALERT WILL REMAIN IN EFFECT FOR TODAY...UNTIL 11 PM. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... WITH LOW LEVEL MOISTURE IN PLACE...AFTER AFTERNOON AND EVENING RAINS...PATCHY FOG WILL DEVELOP ONCE AGAIN ACROSS THE REGION TONIGHT. USED A BLEND OF MAV/MET MOS FOR OVERNIGHT MIN TEMPERATURES. MORE SHOWERS AND STORMS ARE POSSIBLE WEDNESDAY AFTERNOON AS A BACKDOOR COLD FRONT MOVES SOUTH ACROSS MAINE AND NEW HAMPSHIRE. SOME OF THESE STORMS MAY BE LOCALLY STRONG AS WELL. READINGS OVER SOUTHERN NEW HAMPSHIRE WILL SHOOT UP QUICKLY AHEAD OF THE SURFACE COLD FRONT...SO A HEAT WAVE (3 CONSECUTIVE DAYS AT OR ABOVE 90 DEGREES) IS STILL POSSIBLE OVER THIS REGION. && .LONG TERM /THURSDAY THROUGH MONDAY/... THE MODELS ARE IN DECENT AGREEMENT WELL INTO NEXT WEEK ON EVOLVING LONGWAVE PATTERN. A SERIES OF SHORTWAVES RIDING OVER THE TOP OF THE WESTERN CONUS RIDGE WILL CARVE OUT A DEEP TROUGH ACROSS THE EAST BY THE UPCOMING WEEKEND. THE OVERALL THEME WILL BE WARM...HUMID...AND WET FOR THE FORECAST PERIOD. IN THE DAILIES...LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES ON THURSDAY THEN SLOW DOWN AND LINGER ACROSS THE NORTHEAST THROUGH EARLY NEXT WEEK PRODUCING WARM, HUMID, AND WET WEATHER ACROSS THE AREA. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... SHORT TERM... MORNING FOG IN SHELTERED VALLEYS WILL LIFT EARLY THIS MORNING. THIS WILL ALLOW FOR SUNNY AND HUMID CONDITIONS...WITH THE DEVELOPMENT OF MORE SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED. PATCHY FOG TO DEVELOP AGAIN TONIGHT WITH LOCAL IFR CONDITIONS...FOLLOWED BY MORE SHOWERS AND STORMS WEDNESDAY AFTERNOON. LONG TERM... THU - SAT...AREAS OF MVFR LIKELY IN SHOWERS AND THUNDERSTORMS. && .MARINE... SHORT TERM... SOUTHWEST FLOW CONTINUES THROUGH TUESDAY BUT SHOULD KEEP CONDITIONS BELOW ADVISORY LEVELS. LONG TERM... FRI - SAT...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
524 AM EDT TUE JUN 25 2013 .SYNOPSIS... STRONG TO POSSIBLY SEVERE THUNDERSTORMS ARE EXPECTED TODAY AS A FRONTAL BOUNDARY SAGS SOUTHWARD ACROSS THE AREA. UNSETTLED CONDITIONS WILL PERSIST THROUGH THE REMAINDER OF THE WEEK AND UPCOMING WEEKEND AS A BROAD AND SLOW MOVING LOW PRESSURE SYSTEM FROM THE GREAT LAKES MOVES EASTWARD.&& .NEAR TERM /THROUGH TONIGHT/... UPDATE 0520L: FEW INITIAL SHOWERS/TSTM INTO XTRM NRN AND WRN MAINE ATTM... ADJUSTED POPS/HRLY TEMPS TO BETTER FIT CURRENT AND EXPECTED TRENDS NXT FEW HRS... QUIET ACROSS THE FA FOR NOW AS WEAKENING BAND OF SHOWERS HAS EXITED OUR SERN AREAS WHILE ANOTHER CLUSTER OF SHOWERS AND TSTMS IS NOTED NW-N OF THE FA ALONG AND JUST W OF THE ST LAWRENCE... NR STATIONARY FRONTAL BNDRY N OF THE REGION XTNDG WNW-ESE FROM JAMES BAY ACROSS THE GASPE AND INTO THE GULF OF THE ST LAWRENCE. SEVERAL WEAK LOWS CONT TO SLIDE ESEWRD ALONG THIS BNDRY W/ THE STRONGEST OF THESE NR THE SERN TIP OF JAMES BAY ATTM. MODELS IN FAIRLY GOOD AGREEMENT AND ALLOW THIS SFC LOW NR JAMES BAY TO DROP SEWRD ALONG THIS FRONTAL BNDRY W/ THE FRONTAL BNDRY SAGGING SWRD ACROSS THE AREA FROM LATE TDY THRU TNGT. VRY WARM/HUMID AND UNSTABLE AIR IN PLACE ACROSS THE AREA S OF THIS BNDRY W/ SBCAPES FCST FROM 1000-2500 J/KG AND THIS WILL COMBINE W/ STRONG SFC AND UPPER DYNAMICS AS THIS FRONTAL BNDRY AND LOW PRES SAG SEWRD TOWARDS THE AREA LATER TDY TO PRODUCE THE THREAT OF STRONG TO PSBLY SEVERE TSTMS ACROSS THE AREA. CURRENTLY THE SPC HAS ALL BUT OUR DOWNEAST AREAS IN A SLIGHT RISK FOR SVR W/ DAMAGING WNDS THE PRIMARY THREAT. INITIAL ACTIVITY NW-N OF THE AREA IS FCST BY THE SHORTER TERM MODEL GUIDANCE LIKE THE HRRR AND RUC TO WEAKEN AND DISSIPATE AS IT REACHES OUR FAR NRN AREAS ERLY THIS AM BUT NOT SURE ABOUT THIS... IN ANY CASE...APPEARS STRONGER ACTIVITY WILL DVLP LATER THIS AM THRU THE AFTN HRS W/ HGHST POPS ACROSS THE N AND E CENTRAL AREAS IN TO THE EVE HRS W/ LOWEST POPS FAR SW. WILL CARRY MENTION OF SVR ALONG W/ ENHANCED WORDING FOR HVY RAIN/DAMAGING WNDS AND SMALL HAIL... FOR TNGT...GUIDANCE SUGGESTS THIS BNDRY WILL BE JUST S AND W OF THE FA BY ERLY WED W/ WEAK LOW PRES CNTRS OVR ERN NS...SRN MAINE AND SWRN QUEBEC. HIGH PRES W/ SOME DRIER AIR MAY TRY TO NUDE INTO FAR NERN AREAS BY LATE TNGT/ERLY WED... EXPECT ANOTHER WARM AND MUGGY DAY TDY W/ HIGH TEMPS LARGELY DEPENDENT ON CLD CVR. THINKING THERE WILL BE SOME SUN N AND NE W/ MORE PREVALENT SUNSHINE S AND W. WILL ADVERTISE HIGHS INTO THE LOWER 80S N W/ NR 90 PSBL SRN AREAS AWAY FROM THE COAST. ANOTHER WARM AND MUGGY NGT TNGT ACROSS RN AND WRN AREAS W/ SOME COOLER AND DRIER AIR LIKELY WORKING INTO NERN AREAS. PLENTY OF LOW LEVEL MOISTURE AND RATHER LGT WNDS SUGGESTS THE THREAT OF FOG TNGT ACROSS MUCH OF THE REGION...&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AN H5 UPPER LOW DEEPENS ACROSS THE GREAT LAKES REGION DURING THIS TIME FRAME. THIS WILL ALLOW AMPLE MOISTURE TO MOVE INTO NORTHERN NEW ENGLAND. EXPECT PERIODS OF SHOWERS BOTH DAYS. HIGHS WILL BE NEAR NORMAL ON WEDNESDAY AND MUCH BELOW NORMAL ON THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AN H5 UPPER LOW SLOWLY PROGRESSES INTO THE NORTHEAST U.S. LATE THIS WEEK AND THEN LIFTS INTO QUEBEC THIS WEEKEND. THIS ALLOWS THE DAMP WEATHER PATTERN TO PERSIST. THURSDAY NIGHT AND FRIDAY ARE FORECAST TO BE PARTICULARLY WET WITH PERIODS OF RAIN. TEMPERATURES WILL GRADUALLY WARM BACK TO SEASONAL LEVELS BY THE WEEKEND. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... NEAR TERM: PATCHY FOG ERLY THIS AM MAY RESULT IN SOME MVFR TO IFR CONDS UP UNTIL OR SHORTLY AFTER SUNRISE. MAINLY VFR CONDS ARE THEN EXPECTED OUTSIDE OF ANY SHOWERS/TSTMS W/ MVFR/IFR DURING THIS ACTIVITY. PATCHY TO AREAS OF FOG EXPECTED AGAIN TNGT ALONG W/ A THREAT OF SHOWERS MAINLY ACROSS THE SRN HALF OF THE FA. SHORT TERM: MVFR AND POSSIBLY IFR CIGS AND VSBYS ARE EXPECTED AT TAF SITES WITH SHOWERS...RAIN AND FOG. && .MARINE... NEAR TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THRU TONIGHT. VISIBILITIES COULD BE REDUCED IN PATCHY FOG TODAY...THEN IN AREAS OF FOG AND ANY SHOWERS/THUNDERSTORMS LATER TODAY AND TONIGHT. SHORT TERM: NO HEADLINES ARE FORECAST. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...KHW SHORT TERM...OKULSKI LONG TERM...OKULSKI AVIATION...KHW/OKULSKI MARINE...KHW/OKULSKI
AREA FORECAST DISCUSSION
NWS GRAY ME
329 AM EDT TUE JUN 25 2013 .SYNOPSIS... HOT AND HUMID AIR CONTINUES TO BE PUSHED NORTH INTO NEW ENGLAND AS SOUTHWEST FLOW PERSISTS OVER THE AREA. THE THREAT FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL ALSO CONTINUE. BY THURSDAY AND FRIDAY THERE IS A CHANCE FOR A MORE CONSISTENT RAIN AS WEAK LOW PRESSURE DEVELOPS TO OUR WEST AND LIFTS NORTHEAST INTO QUEBEC. THIS WILL ALSO SHIFT THE WINDS MORE ONSHORE...WITH COOLER TEMPERATURES AT THE END OF THE WEEK...ALTHOUGH HUMIDITY`S WILL NOT DROP OFF THAT MUCH. WE WILL SWITCH BACK TO A SOUTHERLY FLOW FOR THE WEEKEND...WITH WARMER AND CONTINUED HUMID CONDITIONS. && .NEAR TERM /THROUGH TODAY/... ..."SUPERMOON" TIDES REACHED 12 FEET IN PORTLAND EARLY THIS MORNING... LATEST HRRR RUN CONTINUES TO INDICATE CONVECTIVE INITIATION BEGINNING AROUND 18Z OVER FAR NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA. THIS IS IN RESPONSE TO SHORT WAVE RACING ACROSS SOUTHERN CANADA. WIND FIELDS WILL BE INCREASING (AND UNIDIRECTIONAL) WITH THIS FEATURE. WITH STEEP LOW LEVEL LAPSE RATES AND HIGH SURFACE DEW POINTS IN PLACE...CONVECTION TODAY WILL BE MORE ORGANIZED THAN YESTERDAY AS THE WIND MAX APPROACHES FROM THE NORTHWEST. DAMAGING STRAIGHT LINE WINDS ARE POSSIBLE IN ISOLATED STORMS...WITH LARGE HAIL POSSIBLE IN ANY OF THE STRONGER STORMS AS CAPE VALUES RAPIDLY CLIMB WITH GOOD SOLAR HEATING TODAY. HAVE ENHANCED WORDING IN THE GRIDS. PRECIPITABLE WATER VALUES REMAIN VERY HIGH. SOME OF THE SHOWERS AND STORMS MAY DROP VERY HEAVY RAIN IN A SHORT PERIOD OF TIME. STORMS WILL BE RELATIVELY FAST MOVING...BUT TRAINING OF SHOWERS WILL NEED TO BE MONITORED. AN AIR QUALITY ALERT WILL REMAIN IN EFFECT FOR TODAY...UNTIL 11 PM. && .SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/... WITH LOW LEVEL MOISTURE IN PLACE...AFTER AFTERNOON AND EVENING RAINS...PATCHY FOG WILL DEVELOP ONCE AGAIN ACROSS THE REGION TONIGHT. USED A BLEND OF MAV/MET MOS FOR OVERNIGHT MIN TEMPERATURES. MORE SHOWERS AND STORMS ARE POSSIBLE WEDNESDAY AFTERNOON AS A BACKDOOR COLD FRONT MOVES SOUTH ACROSS MAINE AND NEW HAMPSHIRE. SOME OF THESE STORMS MAY BE LOCALLY STRONG AS WELL. READINGS OVER SOUTHERN NEW HAMPSHIRE WILL SHOOT UP QUICKLY AHEAD OF THE SURFACE COLD FRONT...SO A HEAT WAVE (3 CONSECUTIVE DAYS AT OR ABOVE 90 DEGREES) IS STILL POSSIBLE OVER THIS REGION. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE MODELS ARE IN DECENT AGREEMENT WELL INTO NEXT WEEK ON EVOLVING LONGWAVE PATTERN. A SERIES OF SHORTWAVES RIDING OVER THE TOP OF THE WESTERN CONUS RIDGE WILL CARVE OUT A DEEP TROUGH ACROSS THE EAST BY THE UPCOMING WEEKEND. THE OVERALL THEME WILL BE WARM...HUMID...AND WET FOR THE FORECAST PERIOD. IN THE DAILIES...LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES ON THURSDAY THEN SLOW DOWN AND LINGER ACROSS THE NORTHEAST THROUGH EARLY NEXT WEEK PRODUCING WARM, HUMID, AND WET WEATHER ACROSS THE AREA. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... SHORT TERM... MORNING FOG IN SHELTERED VALLEYS WILL LIFT EARLY THIS MORNING. THIS WILL ALLOW FOR SUNNY AND HUMID CONDITIONS...WITH THE DEVELOPMENT OF MORE SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED. PATCHY FOG TO DEVELOP AGAIN TONIGHT WITH LOCAL IFR CONDITIONS...FOLLOWED BY MORE SHOWERS AND STORMS WEDNESDAY AFTERNOON. LONG TERM... THU - SAT...AREAS OF MVFR LIKELY IN SHOWERS AND THUNDERSTORMS. && .MARINE... SHORT TERM... SOUTHWEST FLOW CONTINUES THROUGH TUESDAY BUT SHOULD KEEP CONDITIONS BELOW ADVISORY LEVELS. LONG TERM... FRI - SAT...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
323 AM EDT TUE JUN 25 2013 .SYNOPSIS... STRONG TO POSSIBLY SEVERE THUNDERSTORMS ARE EXPECTED TODAY AS A FRONTAL BOUNDARY SAGS SOUTHWARD ACROSS THE AREA. UNSETTLED CONDITIONS WILL PERSIST THROUGH THE REMAINDER OF THE WEEK AND UPCOMING WEEKEND AS A BROAD AND SLOW MOVING LOW PRESSURE SYSTEM FROM THE GREAT LAKES MOVES EASTWARD.&& .NEAR TERM /THROUGH TONIGHT/... QUIET ACROSS THE FA FOR NOW AS WEAKENING BAND OF SHOWERS HAS EXITED OUR SERN AREAS WHILE ANOTHER CLUSTER OF SHOWERS AND TSTMS IS NOTED NW-N OF THE FA ALONG AND JUST W OF THE ST LAWRENCE... NR STATIONARY FRONTAL BNDRY N OF THE REGION XTNDG WNW-ESE FROM JAMES BAY ACROSS THE GASPE AND INTO THE GULF OF THE ST LAWRENCE. SEVERAL WEAK LOWS CONT TO SLIDE ESEWRD ALONG THIS BNDRY W/ THE STRONGEST OF THESE NR THE SERN TIP OF JAMES BAY ATTM. MODELS IN FAIRLY GOOD AGREEMENT AND ALLOW THIS SFC LOW NR JAMES BAY TO DROP SEWRD ALONG THIS FRONTAL BNDRY W/ THE FRONTAL BNDRY SAGGING SWRD ACROSS THE AREA FROM LATE TDY THRU TNGT. VRY WARM/HUMID AND UNSTABLE AIR IN PLACE ACROSS THE AREA S OF THIS BNDRY W/ SBCAPES FCST FROM 1000-2500 J/KG AND THIS WILL COMBINE W/ STRONG SFC AND UPPER DYNAMICS AS THIS FRONTAL BNDRY AND LOW PRES SAG SEWRD TOWARDS THE AREA LATER TDY TO PRODUCE THE THREAT OF STRONG TO PSBLY SEVERE TSTMS ACROSS THE AREA. CURRENTLY THE SPC HAS ALL BUT OUR DOWNEAST AREAS IN A SLIGHT RISK FOR SVR W/ DAMAGING WNDS THE PRIMARY THREAT. INITIAL ACTIVITY NW-N OF THE AREA IS FCST BY THE SHORTER TERM MODEL GUIDANCE LIKE THE HRRR AND RUC TO WEAKEN AND DISSIPATE AS IT REACHES OUR FAR NRN AREAS ERLY THIS AM BUT NOT SURE ABOUT THIS... IN ANY CASE...APPEARS STRONGER ACTIVITY WILL DVLP LATER THIS AM THRU THE AFTN HRS W/ HGHST POPS ACROSS THE N AND E CENTRAL AREAS IN TO THE EVE HRS W/ LOWEST POPS FAR SW. WILL CARRY MENTION OF SVR ALONG W/ ENHANCED WORDING FOR HVY RAIN/DAMAGING WNDS AND SMALL HAIL... FOR TNGT...GUIDANCE SUGGESTS THIS BNDRY WILL BE JUST S AND W OF THE FA BY ERLY WED W/ WEAK LOW PRES CNTRS OVR ERN NS...SRN MAINE AND SWRN QUEBEC. HIGH PRES W/ SOME DRIER AIR MAY TRY TO NUDE INTO FAR NERN AREAS BY LATE TNGT/ERLY WED... EXPECT ANOTHER WARM AND MUGGY DAY TDY W/ HIGH TEMPS LARGELY DEPENDENT ON CLD CVR. THINKING THERE WILL BE SOME SUN N AND NE W/ MORE PREVALENT SUNSHINE S AND W. WILL ADVERTISE HIGHS INTO THE LOWER 80S N W/ NR 90 PSBL SRN AREAS AWAY FROM THE COAST. ANOTHER WARM AND MUGGY NGT TNGT ACROSS RN AND WRN AREAS W/ SOME COOLER AND DRIER AIR LIKELY WORKING INTO NERN AREAS. PLENTY OF LOW LEVEL MOISTURE AND RATHER LGT WNDS SUGGESTS THE THREAT OF FOG TNGT ACROSS MUCH OF THE REGION... && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AN H5 UPPER LOW DEEPENS ACROSS THE GREAT LAKES REGION DURING THIS TIME FRAME. THIS WILL ALLOW AMPLE MOISTURE TO MOVE INTO NORTHERN NEW ENGLAND. EXPECT PERIODS OF SHOWERS BOTH DAYS. HIGHS WILL BE NEAR NORMAL ON WEDNESDAY AND MUCH BELOW NORMAL ON THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AN H5 UPPER LOW SLOWLY PROGRESSES INTO THE NORTHEAST U.S. LATE THIS WEEK AND THEN LIFTS INTO QUEBEC THIS WEEKEND. THIS ALLOWS THE DAMP WEATHER PATTERN TO PERSIST. THURSDAY NIGHT AND FRIDAY ARE FORECAST TO BE PARTICULARLY WET WITH PERIODS OF RAIN. TEMPERATURES WILL GRADUALLY WARM BACK TO SEASONAL LEVELS BY THE WEEKEND. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... NEAR TERM: PATCHY FOG ERLY THIS AM MAY RESULT IN SOME MVFR TO IFR CONDS UP UNTIL OR SHORTLY AFTER SUNRISE. MAINLY VFR CONDS ARE THEN EXPECTED OUTSIDE OF ANY SHOWERS/TSTMS W/ MVFR/IFR DURING THIS ACTIVITY. PATCHY TO AREAS OF FOG EXPECTED AGAIN TNGT ALONG W/ A THREAT OF SHOWERS MAINLY ACROSS THE SRN HALF OF THE FA. SHORT TERM: MVFR AND POSSIBLY IFR CIGS AND VSBYS ARE EXPECTED AT TAF SITES WITH SHOWERS...RAIN AND FOG. && .MARINE... NEAR TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THRU TONIGHT. VISIBILITIES COULD BE REDUCED IN PATCHY FOG TODAY...THEN IN AREAS OF FOG AND ANY SHOWERS/THUNDERSTORMS LATER TODAY AND TONIGHT. SHORT TERM: NO HEADLINES ARE FORECAST. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...KHW SHORT TERM...OKULSKI LONG TERM...OKULSKI AVIATION...KHW/OKULSKI MARINE...KHW/OKULSKI
AREA FORECAST DISCUSSION
NWS GRAY ME
302 AM EDT TUE JUN 25 2013 .SYNOPSIS... HOT AND HUMID AIR CONTINUES TO BE PUSHED NORTH INTO NEW ENGLAND AS SOUTHWEST FLOW PERSISTS OVER THE AREA. THE THREAT FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL ALSO CONTINUE. BY THURSDAY AND FRIDAY THERE IS A CHANCE FOR A MORE CONSISTENT RAIN AS WEAK LOW PRESSURE DEVELOPS TO OUR WEST AND LIFTS NORTHEAST INTO QUEBEC. THIS WILL ALSO SHIFT THE WINDS MORE ONSHORE...WITH COOLER TEMPERATURES AT THE END OF THE END OF THE WEEK...ALTHOUGH HUMIDITY`S WILL NOT DROP OFF THAT MUCH. WE WILL SWITCH BACK TO A SOUTHERLY FLOW FOR THE WEEKEND...WITH WARMER AND CONTINUED HUMID CONDITIONS. && .NEAR TERM /THROUGH TODAY/... ..."SUPERMOON" TIDES REACHED 12 FEET IN PORTLAND EARLY THIS MORNING... LATEST HRRR RUN CONTINUES TO INDICATE CONVECTIVE INITIATION BEGINNING AROUND 18Z OVER FAR NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA. THIS IS IN RESPONSE TO SHORT WAVE RACING ACROSS SOUTHERN CANADA. WIND FIELDS WILL BE INCREASING (AND UNIDIRECTIONAL) WITH THIS FEATURE. WITH STEEP LOW LEVEL LAPSE RATES AND HIGH SURFACE DEW POINTS IN PLACE...CONVECTION TODAY WILL BE MORE ORGANIZED THAN YESTERDAY AS THE WIND MAX APPROACHES FROM THE NORTHWEST. DAMAGING STRAIGHT LINE WINDS ARE POSSIBLE IN ISOLATED STORMS...WITH LARGE HAIL POSSIBLE IN ANY OF THE STRONGER STORMS AS CAPE VALUES RAPIDLY CLIMB WITH GOOD SOLAR HEATING TODAY. HAVE ENHANCED WORDING IN THE GRIDS. PRECIPITABLE WATER VALUES REMAIN VERY HIGH. SOME OF THE SHOWERS AND STORMS MAY DROP VERY HEAVY RAIN IN A SHORT PERIOD OF TIME. STORMS WILL BE RELATIVELY FAST MOVING...BUT TRAINING OF SHOWERS WILL NEED TO BE MONITORED. AN AIR QUALITY ALERT WILL REMAIN IN EFFECT FOR TODAY...UNTIL 11 PM. && .SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/... WITH LOW LEVEL MOISTURE IN PLACE...AFTER AFTERNOON AND EVENING RAINS...PATCHY FOG WILL DEVELOP ONCE AGAIN ACROSS THE REGION TONIGHT. USED A BLEND OF MAV/MET MOS FOR OVERNIGHT MIN TEMPERATURES. MORE SHOWERS AND STORMS ARE POSSIBLE WEDNESDAY AFTERNOON AS A BACKDOOR COLD FRONT MOVES SOUTH ACROSS MAINE AND NEW HAMPSHIRE. SOME OF THESE STORMS MAY BE LOCALLY STRONG AS WELL. READINGS OVER SOUTHERN NEW HAMPSHIRE WILL SHOOT UP QUICKLY AHEAD OF THE SURFACE COLD FRONT...SO A HEAT WAVE (3 CONSECUTIVE DAYS AT OR ABOVE 90 DEGREES) IS STILL POSSIBLE OVER THIS REGION. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE MODELS ARE IN DECENT AGREEMENT WELL INTO NEXT WEEK ON EVOLVING LONGWAVE PATTERN. A SERIES OF SHORTWAVES RIDING OVER THE TOP OF THE WESTERN CONUS RIDGE WILL CARVE OUT A DEEP TROUGH ACROSS THE EAST BY THE UPCOMING WEEKEND. THE OVERALL THEME WILL BE WARM...HUMID...AND WET FOR THE FORECAST PERIOD. IN THE DAILIES...LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES ON THURSDAY THEN SLOW DOWN AND LINGER ACROSS THE NORTHEAST THROUGH EARLY NEXT WEEK PRODUCING WARM, HUMID, AND WET WEATHER ACROSS THE AREA. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... SHORT TERM... MORNING FOG IN SHELTERED VALLEYS WILL LIFT EARLY THIS MORNING. THIS WILL ALLOW FOR SUNNY AND HUMID CONDITIONS...WITH THE DEVELOPMENT OF MORE SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED. PATCHY FOG TO DEVELOP AGAIN TONIGHT WITH LOCAL IFR CONDITIONS...FOLLOWED BY MORE SHOWERS AND STORMS WEDNESDAY AFTERNOON. LONG TERM... THU - SAT...AREAS OF MVFR LIKELY IN SHOWERS AND THUNDERSTORMS. && .MARINE... SHORT TERM... SOUTHWEST FLOW CONTINUES THROUGH TUESDAY BUT SHOULD KEEP CONDITIONS BELOW ADVISORY LEVELS. LONG TERM... FRI - SAT...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
245 PM EDT TUE JUN 25 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL CONTINUE. IN ADDITION...SEVERAL UPPER LEVEL DISTURBANCES WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS UNTIL A COLD FRONT PASSES ON THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... LOOKS LIKE CONVECTION WILL CONTINUE TO DEVELOP IN THE VICINITY OF THE TRAILING OUTFLOW BOUNDARY THAT IS CURRENTLY SET UP ROUGHLY ALONG THE I-80 CORRIDOR. WHILE THE MESOSCALE ANALYSIS SUGGESTS PLENTY OF INSTABILITY...WITH CAPE IN EXCESS OF 2500-3000 J/KG...SHEAR CONTINUES TO REMAIN MARGINAL AT BEST. THIS HAS LEAD TO VERY DISORGANIZED STORMS THUS FAR. HOWEVER...SEVERAL OF THE HI RES MODELS ARE CONTINUING TO SUGGEST A BIT MORE ORGANIZATION BY LATE THIS AFTERNOON. BOTH THE HRRR AND 4KM NAM SUGGEST THAT A MCS WILL DEVELOP AND PROPAGATE ALONG THIS SLOWLY SINKING BOUNDARY MENTIONED ABOVE...CROSSING THE FORECAST AREA BY 8PM. NOT COMPLETELY SOLD ON MCS DEVELOPMENT BUT...SINCE THE DETERMINISTIC MODELS CONTINUE TO SHOW A BREAK DOWN IN THE RIDGE AS A WEAK SHORTWAVE MOVES ACROSS THE GREAT LAKES THIS EVENING...BELIEVE THIS COULD BE ENOUGH TO AT LEAST HELP SOME STORMS REACH STRONG TO SEVERE LEVELS. FOR NOW...CONTINUED THE SCATTERED COVERAGE WORDING FOR THUNDERSTORMS AND WILL CONTINUE TO MONITOR UPSTREAM TRENDS. A SIMILAR SCENARIO REMAINS IN PLACE FOR WEDNESDAY. MODEL SOUNDINGS CONTINUE TO SUGGEST A BRIEF NORTHWESTERLY WIND COMPONENT AT MID LEVELS COULD POSSIBLY HELP SUPPORT STRONGER STORMS WEDNESDAY AFTERNOON...BUT COVERAGE REMAINS UNCERTAIN. A PERSISTENCE FORECAST FOR TEMPERATURES WAS MAINTAINED THROUGH THE PERIOD. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... STRONG AGREEMENT AMONGST NCEP CHAIN ON A MODEST MID LVL WAVE CROSSING THE WESTERN GREAT LAKES WED NGT INTO THUR. CONFIDENCE HAS INCREASED TO RAISE POPS FURTHER INTO THE CATEGORICAL RANGE. TIME OF DAY DOES NOT LEND ITSELF TO HAZARDOUS WEATHER...SO PRESENT THINKING IS WE EXPERIENCE A WELCOME RAIN WITH SCATTERED SUB-SEVERE STORMS. PROGRESSIVE PATTERN WITH IMPULSES CROSSING EVERY 18 TO 24 HOURS DOES NOT LEND ITSELF MUCH TIME FOR INSERTION OF DRY WEATHER. CONTINUED WITH CHANCE POPS THE BALANCE OF SHORT TERM AS INHERITED DATASET PRESENTLY ILLUSTRATES. THERMODYNAMIC PARAMETERS ARE NOT IMPRESSIVE FRIDAY FOR A SEVERE THREAT DESPITE A STRONG KINEMATIC ENVIRONMENT. SBCAPES PUSH 2.0 KJKG-1 W OF I-77 ALONG WITH BETTER BL EQUIV POT TEMP ADV...BUT MID LVL LAPSE RATES ARE MARGINAL /AROUND 5CKM-1 OR LESS/. AS H5 CYCLONE COILS UP ACRS EASTERN CANADA...ASSOCIATED HEIGHT FALLS WILL BRING COOLER AND LESS HUMID WEATHER OVER THE WEEKEND. INTERSECTION OF INSTABILITY AND LIFT WILL COINCIDE ON THE LEADING EDGE OF H7-H3 DCVA SUPPORTING RW/TRW DEVELOPMENT CLOSER TO LAKE ERIE. A COLD FRONT ENCROACHES SAT NGT BUT LIMITED MOISTURE ACCOMPANIES IT. DUE TO STAGNANT PATTERN LEANED HEAVILY ON BIAS CORRECTED MOSGUIDE GRIDS FOR TEMPS WHICH HAVE PREFORMED WELL RECENTLY. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... A SERIES OF SHRTWVS WL CONT TO DROP SE ACRS THE GT LKS RGN THRU MOST OF THE PD. THIS WL SPPRT SHWR/TSTM CHCS AT LEAST THRU SAT. MOISTURE MORE IN QUESTION BY SUN SO ONLY MENTIONED SLGT CHC POPS THEN. OTRW...WENT NO HIGHER THAN CHC POPS ATTM DUE TO TIMING UNCERTAINTIES IN INDIVIDUAL SHRTWVS. EXP TEMPS NR OR A SLGTLY ABV SEASONAL AVGS UNTIL HIGH PRES BLDS IN LT IN THE PD WITH SLGTLY BLO AVG READINGS. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... VFR CONDS CURRENTLY. BECOMING MORE UNSTABLE AS THE HEATING CONTINUES. DISTURBANCE MOVING ALONG THE OUTFLOW BOUNDARY FROM THE OVERNIGHT MCS WILL BE THE FOCUS OF THE NEXT CLUSTER OF STORMS THAT WILL MOVE THROUGH THE TAF SITES EARLY THIS EVENING WITH MVFR RESTRICTIONS IN TSRA. PTCHY MVFR IN BR IS PSBL FOR MANY TAF SITES DURING THE SUNRISE HOURS ON WEDNESDAY. OUTLOOK.../WEDNESDAY THROUGH SATURDAY/... VFR IS EXPD MUCH OF THE TIME...ALTHOUGH A SERIES OF DISTURBANCES WL BRING DAILY CHCS OF SHWRS/TSTMS WITH THE HIGHEST CHC BEING THU/THU NGT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
431 PM EDT TUE JUN 25 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 430 PM EDT TUE JUN 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A LOW AMPLITUDE PATTERN WITH A TROUGH INTO THE PAC NW AND A RIDGE FROM THE UPPER MS VALLEY INTO MANITOBA. THE MAIN UPSTREAM SHORTWAVE TROUGH EXTENDED FROM ERN MONTANA INTO WRN SD. AT THE SFC...A WEAK RIDGE AND LIGHT PRES GRADIENT PREVAILED OVER THE THE REGION ALLOWING PROMINENT LAKE BREEZES TO DEVELOP. CAPPING HAS BEEN STRONG ENOUGH TO SUPPRESS CONVECTION THROUGH 20Z DESPITE LOW LEVEL CONV...INLAND MLCAPE VALUES TO NEAR 1500 J/KG AND CU/TCU LINE DEVELOPMENT. MIXING HAS ALSO BEEN STRONG ENOUGH TO DROP DEWPOINTS INTO THE MID AND UPPER 50S NEAR THE WI BORDER TONIGHT...POTENTIAL REMAINS FOR SOME ISOLD SHRA/TSRA DEVELOPMENT...MAINLY OVER THE SOUTH NEAR THE LAKE BREEZE BOUNDARIES. WITH THE LOSS OF DAYTIME HEATING...ANY PCPN CHANCES WILL ALSO DIMINISH THIS EVENING. EVEN WITH FAVORABLE RADIATIONAL COOLING OVERNIGHT...ENOUGH LOW LEVEL MOISTURE REMAINS TO KEEP MIN TEMPS FROM DROPPING MUCH BELOW 60F. SOME PATCHY FOG MAY ALSO DEVELOP. WED...THE NRN PLAINS SHRTWV AND ASSOCIATED SFC TROUGH MOVING INTO THE WRN LAKES WILL BE THE FOCUS FOR SHRA/TSRA DEVELOPMENT. THE MODELS WERE IN RELATIVELY GOOD AGREEMENT BRINGING THE HIGHER PCPN CHANCES INTO THE WEST HALF OF THE CWA DURING THE AFTERNOON. THE AIRMASS OVER REGION SHOULD AGAIN ALLOW TEMPS TO CLIMB INTO THE LOWER 80S INLAND AND BEFORE LAKE BREEZES TAKE OVER. MLCAPE VALUES MAY AGAIN CLIMB TO AROUND 1500 J/KG BUT RELATIVELY MODEST SHEAR VALUES WILL LIMIT STRONG/SEVERE STORM POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 430 PM EDT TUE JUN 25 2013 OVERALL PATTERN WILL EVOLVE INTO AN AMPLIFIED ONE FOR LATE JUNE STANDARDS DURING THE LATE WEEK PERIOD WITH INTENSE UPPER RIDGING DEVELOPING OVER THE WESTERN U.S. AND TROUGHING DEVELOPING OVER THE GREAT LAKES AND EASTERN U.S. AS HAS BEEN THE CASE OVER THE LAST SEVERAL DAYS TIMING OF A BETTER PRECIP CHANCES DURING THE NEXT COUPLE OF DAYS WILL REMAIN A CHALLENGE. CONFIDENCE IS PRETTY HIGH THAT ALL AREAS WILL SEE AT LEAST SOME RAINFALL BETWEEN THE WEDNESDAY NIGHT THROUGH SATURDAY TIME PERIOD. HOWEVER...MORE OF THAT TIME WILL BE DRY RATHER THAN RAINY. WHILE SCATTERED POPS SEEM THE WAY TO GO FOR THIS TIME PERIOD...WILL GO WITH SLIGHTLY HIGHER POPS DURING THE WED NIGHT TIME PERIOD AS SHORTWAVE ENERGY BEGINS TO CARVE OUT UPPER TROUGHING OVER THE GREAT LAKES. WILL ALSO GO ON THE HIGHER END OF CHANCE POPS FOR FRIDAY INTO SATURDAY AS MAIN TROUGH AXIS MOVES THROUGH THE AREA. A SCATTERING OF POPS DURING THE OTHER PERIODS SEEMS REASONABLE. WITH LIMITED INSTABILITY AND SHEAR EXPECTED...THUNDER CHANCES WILL BE MORE IN THE ISOLATED TO SLIGHT CHANCE RANGE. HIGH PRESSURE AND DRIER AIR SHOULD BEGIN PUSHING INTO THE AREA FROM THE NORTH BY LATE IN THE DAY SATURDAY ENDING THE RAIN CHANCES. UPPER TOUGHING WILL REMAIN OVER THE AREA INTO EARLY NEXT WEEK KEEPING TEMPERATURES AT TO JUST SLIGHTLY BELOW NORMAL THROUGH THE WEEKEND INTO MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 154 PM EDT TUE JUN 25 2013 MAINLY VFR CONDITIONS WILL PREVAIL THRROUGH THIS FCST PERIOD AT KIWD/KCMX/KSAW. RADIATAIONAL COOLING MAY ALLOW SOME FOG TO DEVELOP LATE TONIGHT AT SAW/IWD DROPPING VSBY INTO THE MVFR RANGE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 430 PM EDT TUE JUN 25 2013 OVERALL...WINDS ARE EXPECTED TO BE BELOW 20KTS THROUGH THE PERIOD AS THE PRESSURE PATTERN REMAINS FAIRLY WEAK ACROSS THE AREA. WITH THE WARM MOIST AIR OVER THE UPPER GREAT LAKES...WILL CONTINUE TO MENTION PATCHY/AREAS OF FOG THROUGH WEDNESDAY NIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MZ AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
142 AM EDT TUE JUN 25 2013 .SYNOPSIS... ISSUED AT 403 PM EDT MON JUN 24 2013 HOT AND HUMID WEATHER WILL CONTINUE ACROSS THE REGION INTO MIDWEEK...AS HIGH PRESSURE DRIFTS OFF THE COAST OF THE SOUTHEAST STATES. THE HEAT AND HUMIDITY WILL BE ACCOMPANIED BY CHANCES OF SHOWERS AND THUNDERSTORMS...AS SEVERAL WAVES OF WEAK LOW PRESSURE TRACK ACROSS THE REGION. TEMPERATURES WILL GRADUALLY COOL DOWN LATE IN THE WEEK AND INTO NEXT WEEKEND...THOUGH CHANCES FOR A FEW SHOWERS WILL REMAIN THROUGH SATURDAY. && .UPDATE... ISSUED AT 125 AM EDT TUE JUN 25 2013 CLOUDS ARE SET TO ROLL IN OVER THE NEXT COUPLE OF HOURS...WHILE ISOLATED/SCATTERED SHOWERS AND STORMS ROLL ACROSS EASTERN UPPER IN RIGHT ENTRANCE REGION OF UPPER JET ROUNDING SHORTWAVE IN ONTARIO. THESE WILL CROSS CHIP/MACK COUNTIES THROUGH 0730Z. MEANWHILE...BACK ACROSS WISCONSIN...THERE APPEARS TO BE TWO SEPARATE SHORTWAVES BASED ON RUC ANALYSIS AND VWP`S. ONE RESULTING IN SLIGHTLY BACKING H8 WINDS BETWEEN LACROSSE AND MILWAUKEE. THIS HAS RESULTED IN SCATTERED SHOWER DEVELOPMENT AROUND GRB...WHICH WAS SLOWLY WORKING TOWARD THE GTV BAY REGION. NOT SURE HOW MUCH OF THAT CAN HOLD TOGETHER WITH GROWING MCS ACROSS SW WISCONSIN WHICH MAY DISRUPT IT`S INFLOW. LATEST HI RES HRRR...DOING A DECENT JOB AND WILL TWEAK POP GRIDS ACCORDINGLY...WITH SCATTERED ACTIVITY ROLLING INTO THE GTV BAY REGION OVER THE NEXT COUPLE OF HOURS. UPDATE ISSUED AT 945 PM EDT MON JUN 24 2013 MCS CONTINUES SLIDING EAST THRU THE NRN OHIO VALLEY THIS EVENING... WITH ADDITIONAL ISOLATED ACTIVITY FURTHER NORTH OVER WISCONSIN/UPPER MICHIGAN. MAIN QUESTION OVERNIGHT REMAINS POPS. BEST LOW LEVEL FORCING/FAVORABLE UPPER LEVEL SUPPORT REMAIN SOUTH/WEST OF THE AREA. AND STILL BELIEVE MUCH OF THE CONVECTION WILL REMAIN SOUTH OF THE CWA OVERNIGHT...LINING UP IN CLOSER PROXIMITY TO 850MB DWPT AXIS LAYING W-E ACROSS THE CENTRAL PORTIONS OF MICHIGAN AND WITHIN CORRIDOR OF SLIGHTLY STRONGER 850MB FLOW. CURRENT CONVECTION OVER UPPER MICHIGAN /LIKELY TIED TO 850MB THETA-E RIDGE NOSING INTO THAT AREA/ SHOULD DISSIPATE AS IT MOVES EAST OVER THE NEXT FEW HOURS. BUT GIVEN THIS ISOLATED ACTIVITY DEVELOPING DESPITE RATHER UNIMPRESSIVE FORCING...SIMPLY CAN/T RULE OUT AT LEAST LOW POPS OVER MUCH OF NRN LOWER MICHIGAN OVERNIGHT. WILL TREND HIGHEST POPS /30-40%/ SOUTH OF M-72...WITH LOWER CHANCES NORTH. STILL HAVE RELATIVELY LOW CONFIDENCE IN OVERALL CONVECTIVE EVOLUTION...AS AIRMASS REMAINS JUICY WITH SEVERAL UPSTREAM SHORTWAVE/VORT CENTERS. ADJUSTED LOW TEMPS UP A FEW DEG MOST LOCALES GIVEN CURRENT DWPTS AND PLENTY OF HIGH/MID LEVEL CLOUDINESS. UPDATE ISSUED AT 635 PM EDT MON JUN 24 2013 DIURNAL ISOLD SHWRS/TSTMS DISSIPATING WITH LOWER SUN ANGLE...AND WILL REMOVE FROM FORECAST OVER THE NEXT HOUR. NUMERICAL GUIDANCE CONTINUING TO STRUGGLE WITH CONVECTIVE TRENDS AND WILL BASE MUCH OF THE FORECAST TONIGHT ON OBSERVATIONAL TRENDS. MCS WORKING THRU SRN WISCONSIN/NRN ILLINOIS EARLY THIS EVENING WITHIN AXIS OF BEST LOW LEVEL BULK SHEAR/MUCAPE...MOVING MAINLY EAST WITH MEAN FLOW. MAIN QUESTION FOR NORTHERN MICHIGAN WILL BE IF ANY ADDITIONAL SHOWER/TSTM ACTIVITY CAN DEVELOP ON THE NORTHERN FRINGE OF CONVECTIVE COMPLEX...MORE CLOSELY ALIGNED WITH SYNOPTIC VORTICITY CENTER OVER SRN MINNESOTA. CAN STILL ENVISION SOME POSSIBILITY OF THIS HAPPENING...ALTHOUGH FEEL CURRENT POPS ARE LIKELY TOO FAR NORTH GIVEN CURRENT EXTRAPOLATION OF FEATURE. BECAUSE OF THIS...WILL TRIM POPS OVER THE NRN 1/2 OF THE AREA LATE TONIGHT...KEEPING SCATTERED SHWR/TSTM MENTION SOUTH OF M-32. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 403 PM EDT MON JUN 24 2013 EARLY AFTERNOON SURFACE ANALYSIS SHOWS A BROAD CIRCULATION AROUND A BERMUDA HIGH ENCOMPASSING THE OHIO VALLEY/GREAT LAKES REGION... PUMPING WARMTH AND HUMIDITY INTO MICHIGAN. REMNANTS OF A COLD FRONT WAS MOVING INTO WESTERN QUEBEC...WHILE A WEAK SURFACE LOW OVER EASTERN NEBRASKA HAS SEVERAL CONVECTIVELY INFLUENCED BOUNDARIES IN ITS VICINITY...AS A SLOW MOVING MCS AHEAD OF IT WORKS ITS WAY ACROSS THE MID MISSISSIPPI VALLEY. CLOSER TO HOME...BROKEN AREA OF AGITATED CU/TCU ACROSS MUCH OF NORTHERN LOWER...AND LYING ALONG LAKE BREEZE BOUNDARY ACROSS CHIPPEWA COUNTY. SCATTERED RADAR RETURNS HAVE POPPED EAST OF I-75 IN NORTHEAST LOWER...AND ALONG THE LAKE SUPERIOR BREEZE ACROSS CHIPPEWA COUNTY JUST SOUTH OF THE SOO WITHIN AN AREA OF 1000-1500J/KG MLCAPE. NUMERICAL GUIDANCE WILL CONTINUE TO BE PROBLEMATIC WITH THIS SCENARIO AS VARIOUS MODELS ARE HAVING DIFFICULT RESOLVING REALITY. MCS ACROSS IOWA IS AN ISSUE FOR TONIGHT...CLEARLY GETTING PUSHED ALONG BOTH BY A SYNOPTIC SCALE SHORT WAVE AND AN EMBEDDED MCV. SYNOPTIC VORTICITY CENTER EVIDENT IN VISIBLE IMAGERY SPINNING INTO SOUTHWEST MINNESOTA...WITH CLOUDS AND SOME SHOWERS/SPOTTY THUNDERSTORMS ROTATING AROUND TO THE NORTH OF THE MAIN MCS. THIS FEATURE TIMES INTO NORTHERN MICHIGAN LATE TONIGHT...SO BEYOND ANY ACTIVITY THAT POPS DURING THE LATE AFTERNOON HOURS...WILL BRING MORE CLOUDS BACK INTO THE REGION OVERNIGHT. MEANWHILE...MCS WILL CONTINUE TO PROPAGATE MOSTLY TO THE EAST BUT ASSOCIATED MCV APPEARS TO BE TRACKING A LITTLE NORTH OF EAST. THUS CAN ENVISION "COMMA HEAD" SHOWERS SLIPPING INTO NORTHERN LOWER MICHIGAN LATER TONIGHT PROVIDED THIS SYSTEM HOLDS TOGETHER. VORTICITY CENTER WILL LIKELY STILL BE CROSSING NORTHERN LOWER TUESDAY MORNING...SO CLOUDS AND SOME SHOWERS PROBABLY STILL AROUND ESPECIALLY SOUTH OF THE BRIDGE TO START THE DAY. IN THE WAKE OF THIS WAVE TO DRY THINGS OUT FOR THE AFTERNOON...ALLOWING TEMPERATURES TO WARM ONCE AGAIN INTO THE 80S. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 403 PM EDT MON JUN 24 2013 SUMMERTIME WARMTH AND HUMIDITY TO CONTINUE INTO MIDWEEK WITH A BIT OF A COOL DOWN THEN EXPECTED NEXT WEEKEND INTO EARLY NEXT WEEK. THIS SHOULD MAKE EVERYONE HAPPY...SOME BEACH WEATHER TO START FOLLOWED BY BETTER SLEEPING CONDITIONS FOR NON-AIR CONDITIONING OWNING PEOPLE (LIKE ME). ANYWAYS...THE UPPER LEVEL RIDGE IN PLACE ACROSS THE REGION OVER THE LAST FEW DAYS GETS SLOWLY BEATEN DOWN THROUGH MIDWEEK BY THE PACIFIC NORTHWEST TROUGH. THIS WILL LEAVE BROAD UPPER TROUGHING ACROSS THE REGION LATER IN THE WEEK...WHICH SHOULD HOLD INTO EARLY NEXT WEEK AS WELL. THE MAIN FORECAST CONCERNS WILL CONTINUE TO REVOLVE AROUND POPS THROUGH THE PERIOD. TUESDAY NIGHT...NOT A WHOLE LOT TO HANG YOUR HAT ON...JUST A CHANCE FOR A COUPLE OF AIRMASS SHOWERS OR THUNDERSTORMS. REMAINING ON THE WARM AND HUMID SIDE WITH LOWS ONLY RANGING FROM THE MIDDLE 60S TO AROUND 70. WEDNESDAY...IT LOOKS LIKE THERE WILL BE A BETTER CHANCE FOR SHOWERS AND STORMS WITH THETA-E RIDGE BUILDING INTO THE REGION...AS WELL AS AN UPPER LEVEL TROUGH MOVING INTO THE REGION FROM THE WEST. THIS MAY WELL BE THE TRIGGER THAT HAS BEEN LACKING OVER THE LAST FEW DAYS TO BRING MORE NUMEROUS SHOWER AND THUNDERSTORM ACTIVITY (ESPECIALLY TO SOUTHERN SECTIONS OF THE FORECAST AREA). THE STORM PREDICTION CENTER (SPC) HAS NIXED THE SLIGHT RISK FOR SEVERE STORMS WHICH MAKES SENSE GIVEN THE ADVERTISED LIGHT WIND FIELDS ALOFT...THOUGH AN ISOLATED SEVERE STORM PROBABLY CAN NOT BE RULED OUT AT THIS EARLY JUNCTURE. CONTINUED VERY WARM AND HUMID WITH HIGHS RANGING FROM THE UPPER 70S NORTH TOT HE MIDDLE 80S SOUTH. LOWS AT NIGHT IN THE LOWER TO MIDDLE 60S. THURSDAY INTO FRIDAY...BROAD UPPER LEVEL TROUGHING IN COMBINATION WITH THE HEATING OF THE DAY AND POSSIBLE LAKE BREEZES WILL BRING ADDITIONAL CHANCES FOR SHOWERS. ADDED THUNDER CHANCES BACK INTO THE MIX FOR THURSDAY AS MODEL SOUNDINGS SHOW A DECENT AMOUNT OF CAPE AND LITTLE IN THE WAY OF INHIBITION. NOT AS WARM BUT STILL MUGGY WITH HIGHS THURSDAY RANGING FROM THE MIDDLE 70S TO LOWER 80S AND FRIDAY FROM THE LOWER 70S TO AROUND 80. LOWS THURSDAY NIGHT IN THE UPPER 50S TO LOWER 60S. SATURDAY THROUGH MONDAY...NOT A LOT OF CHANGE SATURDAY WITH LINGERING TROUGHING LEADING TO ADDITIONAL CHANCES FOR SHOWERS. SLOWLY RISING HEIGHTS FOR SUNDAY AND MONDAY (THOUGH LATEST ECMWF HOLDS ONTO THE TROUGH LONGER) WILL LEAD TO DECREASING CHANCES FOR SHOWERS. FORECAST HIGHS ALL THREE DAYS IN THE LOWER TO MIDDLE 70S. LOWS IN THE MORE COMFORTABLE 50S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 125 AM EDT TUE JUN 25 2013 A WEAK DISTURBANCE WILL MOVE ACROSS NORTHERN MICHIGAN THROUGH TUESDAY MORNING...RESULTING IN LOW CHANCES OF A SHOWER OR THUNDERSTORM AT ALL TERMINALS. THE CHANCE OF PCPN IS TOO LOW TO WARRANT A MENTION IN THE TAF. MAINLY MID/HIGH CLOUDS...WITH ISOLATED MVFR CIGS POSSIBLE NEAR PCPN. DIURNAL CU DEVELOPING TUESDAY AFTN...WITH BASES FROM 4-6K. WINDS GENERALLY LESS THAN 10KTS...WITH LAKE BREEZES POSSIBLE ON LAKE HURON. && .MARINE... ISSUED AT 403 PM EDT MON JUN 24 2013 WINDS WILL REMAIN LIGHT THROUGH THE MIDWEEK PERIOD...AND WILL BE INFLUENCED BY LAKE BREEZE CIRCULATIONS TUESDAY AFTERNOON. VISIBILITIES WILL BE LIMITED AT TIMES DUE TO FOG AND HAZE GIVEN HUMID AIR MASS IN PLACE ACROSS THE UPPER LAKES. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...SD SYNOPSIS...NS SHORT TERM...JB LONG TERM...AS AVIATION...JK MARINE...JB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
638 PM CDT WED JUN 26 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 337 PM CDT WED JUN 26 2013 CLUSTERS OF SHOWERS AND THUNDERSTORMS HAVE ADVANCED EASTWARD INTO WISCONSIN THIS AFTERNOON...BUT AN OUTFLOW BOUNDARY EXISTS FROM ROUGHLY GOODHUE UP THROUGH THE TWIN CITIES METRO. WINDS HAVE VEERED WEST OF THIS BOUNDARY AND DEW POINTS HAVE FALLEN INTO THE 50S AND 60S. ASIDE FROM THE POSSIBILITY OF A COUPLE CELLS DEVELOPING ALONG THE OUTFLOW BOUNDARY AND THOSE ONGOING ACROSS WRN WI...NOT ANTICIPATING MUCH ELSE THIS EVENING. A SECONDARY FRONT WILL SAG SOUTH FROM NRN MN AND THE DAKOTAS WHICH COULD BE A FOCUS FOR ADDITIONAL ACTIVITY OVER CENTRAL MN AND NWRN WI OVERNIGHT. MUCAPE OF AROUND 1000 J/KG AND STRENGTHENING MID LEVEL SHEAR WILL SUPPORT A FEW STORMS...BUT THE THREAT SHOULD BE ISOLATED AND LIKELY NON-SEVERE. CYCLONIC FLOW WITH A DIGGING GREAT LAKES TROUGH COULD CONTINUE THE LOW CHANCE OF TSRA INTO THURSDAY OVER WRN WI. OTHERWISE...DRIER NORTHWEST FLOW AND 925 MB TEMPS OF +24C WILL ALLOW FOR ANOTHER WARM DAY IN THE MID/UPPER 80S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 337 PM CDT WED JUN 26 2013 THE OVERALL EVOLUTION OF THE UPPER LEVEL FLOW PATTERN IS THE MAIN PROBLEM IN THE LONG TERM. MOST DETERMINISTIC MODELS DROP SIGNIFICANT TROUGH OVER THE EASTERN CONUS DURING THE PERIOD. THE INITIAL SURGE OF FALLING HEIGHTS AND MOISTURE MOVES INTO THE REGION FRIDAY AND SATURDAY. THIS WILL SPREAD HIGH CHANCE POPS WEST AND SOUTH OVER THE AREA THROUGH THIS PERIOD. INSTABILITY ASSOCIATED WITH THIS FEATURE IS LIMITED AND WILL MENTION JUST ISOLATED THUNDER WITH THIS ACTIVITY. WITH MORE EXTENSIVE CLOUD COVER... TEMPERATURES SHOULD BE LIMITED TO THE 70S ON SATURDAY AS THE TROUGH MOVES THROUGH. FOR THE REMAINDER OF THE WEEKEND AND INTO EARLY NEXT WEEK...THE WESTERN CONUS RIDGE ON BOTH THE GFS AND ECMWF ARE INDICATING A GENERAL RETROGRESSION OF THE RIDGE...WITH ANOTHER STRONG WAVE RIDING THE EASTERN EDGE OF THIS RIDGE SOUTHWARD AND CARVING A DEEPER UPPER LOW PRESSURE AREA OVER THE CENTRAL CONUS. THIS SHOULD PROVIDE A RATHER COOL AND POSSIBLY INCREASINGLY WETTER PERIOD AS THE UPPER LOW SETTLES OVER THE AREA. THE CURRENT 8 TO 14 DAY FORECAST FOR THE AREA HAS COOLER AND DRIER CONDITIONS FOR THE AREA INTO THE EARLY PART OF NEXT MONTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 621 PM CDT WED JUN 26 2013 A COUPLE OF BOUNDARIES OF INTEREST OUT THERE THIS EVENING. MAIN COLD FRONT/OUTFLOW BOUNDARY IS NOW PUSHING INTO WRN WI. MOST TSRA ACTIVITY WITH THIS HAS NOW PUSHED EAST OF EAU AND WITH ONLY ONE ISOLATED CELL OUT THERE...DO NOT HAVE ANY MORE PRECIP MENTION AT WI TERMINALS. A SECONDARY BOUNDARY IS NOW PUSHING THROUGH ERN NODAK AND CENTRAL SODAK AND WILL BE WORKING ACROSS THE MPX AREA TONIGHT. HRRR HAS BEEN TAKING STORMS CURRENTLY OVER SE NODAK TOWARD WRN MN...GETTING THERE AROUND 2Z...SO ADDED A VCSH MENTION AT AXN/RWF FOR THE POTENTIAL OF THAT ACTIVITY GETTING THERE. OTHERWISE...EXPECT SCT TSRA THROUGH THE NIGHT ACROSS NRN MN INTO NW WI AS THE FRONT COMES THROUGH...WITH THE MAIN QUESTION BEING HOW FAR SOUTH DOES IT GET. GIVEN UNCERTAINTY...CONTINUED TO ONLY THICKEN CLOUD COVER THROUGH THE NIGHT...BUT LAST COUPLE RUNS OF THE HRRR HAVE BEEN BRINGING THIS ACTIVITY CLOSE TO STC/MSP/RNH...SO THIS WILL NEED TO BE WATCHED. WILL ALSO HAVE TO WATCH FOR FOG POTENTIAL...ESPECIALLY AT EAU WHERE HEAVY RAINS WERE OBSERVED THIS AFTERNOON. CURRENT THINKING IS THAT INCREASING CLOUD COVER THROUGH THE NIGHT WILL KEEP VIS RESTRICTION IFR AT WORST. FINALLY...FOR THURSDAY...DOES LOOK LIKE IT SHOULD GET QUITE BREEZY AS NW 850 WINDS INCREASE TO BETWEEN 25 AND 30 KTS IN THE AFTERNOON. IN ADDITION...COULD BE SEE SOME SHOWERS OVER WRN WI AGAIN...BUT SOUNDINGS SHOW MOISTURE LACKING FOR THURSDAY...SO DO NOT HAVE ANY PRECIP MENTION AT THIS POINT FOR RNH/EAU...JUST ANTICIPATING THE DENSEST CU FIELD TO BE THERE FOR NOW. KMSP...ONLY POTENTIAL ISSUE FOR MSP WOULD BE A SHRA/TSRA THREAT LATE TONIGHT AS NEXT FRONT WORKS THROUGH. BASED ON THE HRRR...ALONG WITH SREF PROBS...THE 8Z TO 11Z TIME FRAME LOOKS TO BE WHEN THE POTENTIAL EXISTS. OTHERWISE...LOOKS GOOD FOR GUSTY NW WINDS WITH A FEW-SCT CU FIELD FOR THURSDAY. /OUTLOOK FOR KMSP/ FRI...VFR. CHC SHRA/TS WITH MVFR. WINDS NW AT 15G20 KTS. SAT...VFR. CHC SHRA/TS WITH MVFR. WINDS NNW AT 10-15 KTS. SUN...VFR. WINDS NE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...BORGHOFF LONG TERM...DWE AVIATION...MPG
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
348 PM CDT TUE JUN 25 2013 .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 344 PM CDT TUE JUN 25 2013 SEVERAL THINGS TO DEAL WITH IN THE SHORT TERM TONIGHT. FIRST...STORMS DEVELOPING IN WARM SECTOR AHEAD OF MCV THAT IS SLIDING EAST THROUGH MO FROM MCS THAT WAS OVER WESTERN MO THIS MORNING...AS WELL AS VARIOUS OLD OUTFLOW BOUNDARIES. THIS ACTIVITY SHOULD DIMINISH MOST LOCATIONS BY EARLY THIS EVENING...THOUGH SOME LINGERING ACTIVITY OVER NORTHEAST MO/WEST CENTRAL IL AS MCV SLIDES EAST. THEN MODELS CONTINUE TO SHOW NEXT MCS DEVELOPING OVER IOWA. FORECAST CORFIDI VECTORS HAVE THIS MCS SLIDE SOUTHEAST TOWARDS FORECAST AREA...MAYBE EVEN MORE SOUTHERLY. SO SHOULD MOVE INTO NORTHERN PORTIONS OF FORECAST AREA BY 06Z. LATEST HRRR RUN IS EVEN FURTHER WEST WITH INITIAL DEVELOPMENT IN SOUTHERN IOWA...SO HAVE RAISED POPS A BIT FURTHER WEST. THERE IS A SLIGHT RISK OF SEVERE WEATHER...WITH THE MAIN THREATS BEING LARGE HAIL AND DAMAGING WINDS. AS FOR TEMPS...TO REMAIN RATHER MILD WITH LOWS IN THE LOW TO MID 70S OVERNIGHT. BYRD .LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY) ISSUED AT 344 PM CDT TUE JUN 25 2013 COMPLEX SCENARIO ON TAP FOR WEDNESDAY WITH LOTS OF UNCERTAINTY TO SPECIFIC FORECAST DETAILS. THE MAIN COMPLICATING FACTOR IS THE OVERNIGHT MCS EXPECTED TO IMPACT WESTERN IL AND PORTIONS OF ERN MO AND WHERE IT WILL BE LOCATED AT DAYBREAK. A CONSENSUS OF MODEL SOLUTIONS HAVE THE DECAYING MCS IN CENTERED THRU IL AT DAYBREAK WITH THE TRAILING FLANK OR BOUNDARY LOCATED ALONG THE MS RIVER IN ERN MO. THE VEERED NATURE OF THE TROPOSPHERIC WINDS AND WLY LLJ WOULD SUGGEST THIS SYTEM SHOULD CONTINUE TO MOVE SEWD IN A DECAYING STATE THROUGH THE MORNING WITH POTENTIAL FOR SOME STORMS ON THE TRAILING BOUNDARY. STRONG HEATING SHOULD COMMENCE DURING THE DAY WITHIN THE WARM SECTOR AHEAD OF THE ENCROACHING COLD FRONT...AS WELL AS WEST OR SOUTHWEST OF ANY REMANANT BOUNDARIES. THE HEATING WILL BE MORE LIMITED WITH EASTWARD EXTENT DUE TO RESIDUAL CLOUDINESS FROM THE MORNING...BUT THE WARM SECTOR IS EXPECTED TO BECOME VERY UNSTABLE AND WEAKLY CAPPED WITH SBCAPE AOA 4000 J/KG. SCATTERED THUNDERSTORMS ARE EXPECTED TO REDEVELOP IN THE AFTERNOON WITHIN THE CONFLUENT ZONE AHEAD OF THE COLD FRONT AND WITH ANY RESIDUAL BOUNDARIES...PRIMARILY FROM EAST CENTRAL/SE MO INTO SOUTH CENTRAL AND SW IL. DEEP LAYER SHEAR OF 30-40 KTS AND THE AMOUNT OF INSTABILITY WOULD FAVOR SUPERCELL AND MULTICELL MODES. THE MORNING CONVECTION AND/OR RESIDUAL CLOUDS PRESENT SOME PROBLEMS WITH RESPECT TO THE MAGNITUDE OF HEAT. I HAVE COOLED TEMPS SLIGHTLY FROM ST LOUIS EASTWARD AND THIS IS HIGHLY DEPENDENT ON MORNING CLOUDS. GIVEN THE UNCERTAINTIES I HAVE DEFERED ON ANY HEAT ADVISORIES WITH HEAT INDICES FORECAST IN THE 100-105 RANGE. STORMS SHOULD BE CLOSE TO EXITING THE CWA OR WILL HAVE EXITED THE CWA BY 00Z THURSDAY. EVEN IN THE WAKE OF THE INITIAL COLD FRONT/BOUNDARY...THURSDAY LOOKS LIKE ANOTHER SEASONABLY HOT DAY. INFACT...IT IS NOT TOTALLY OUT OF THE QUESTION IT COULD BE HOTTER THAN WEDNESDAY BUT WITH LESSER HUMIDITY. THE ANTICIPATED NORTHWEST FLOW SHORTWAVE AND SECONDARY COLD FRONT WILL MOVE THROUGH THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY WITH A PROMINENT WSW LLJ AHEAD OF IT. THIS SHOULD FUEL ANOTHER MCS WHICH WILL IMPACT PORTIONS OF THE CWA. THE MODELS DIVERGE ON THE MCS TRACK WITH THE GREATEST PROBABILITY ATTM APPEARING TO BE THROUGH CENTRAL MO. MUCH COOLER AIR WILL THEN SPREAD INTO THE AREA IN THE WAKE OF THE FRONT FOR FRIDAY AND SET THE STAGE FOR A PROLONGED PERIOD OF BELOW AVERAGE TEMPERATURES INTO THE EXTENDED RANGES. THE EXTENDED RANGES WILL FEATURE AN AMPLIFIED BLOCKY UPPER AIR REGIME FROM THE ERN PACIFIC ACROSS THE CONUS INTO THE WRN ATLANTIC...WITH A STRONG UPPER HIGH/RIDGE CENTERED IN THE WRN U.S. AND DEEP TROF IN THE ERN U.S. A SERIES OF SHORT WAVES WILL DROP SSEWD DOWN THE BACKSIDE OF THE UPPER TROF AND IMPACT THE AREA ON SUNDAY AND TUESDAY REINFORCING THE "COOLER" AIR AND BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. GLASS && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1255 PM CDT TUE JUN 25 2013 ONCE AGAIN SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP THIS AFTERNOON OVER PORTIONS OF THE FORECAST AREA. BEST CHANCES WILL BE OVER KUIN AND METRO AREA TAFS. TIMING AND COVERAGE STILL HARD TO PIN DOWN...SO JUST HAVE VCTS MENTION FOR NOW. WILL UPDATE AS NEEDED. OTHERWISE...GUSTY SOUTHWEST WINDS TO 25 KTS AT TIMES. WINDS AND STORMS TO DIMINISH EARLY THIS EVENING. THEN MCS DEVELOPMENT POSSIBLE OVER SOUTHEASTERN IOWA...SLIDING SOUTHEAST...PROBABLY SKIRTING KUIN. SO KEPT PROB30 MENTION FOR KUIN FROM 08Z TO 12Z WEDNESDAY. MAIN COLD FRONT TO SLIDE THROUGH ON WEDNESDAY. WINDS TO VEER TO THE WEST BY MID TO LATE MORNING...WITH STORMS POSSIBLE OVER METRO AREA AHEAD OF FRONT. SPECIFICS FOR KSTL...ONCE AGAIN SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP THIS AFTERNOON OVER PORTIONS OF THE FORECAST AREA. BEST CHANCES WILL BE OVER KUIN AND METRO AREA TAFS. TIMING AND COVERAGE STILL HARD TO PIN DOWN...SO JUST HAVE VCTS MENTION FOR NOW. WILL UPDATE AS NEEDED. OTHERWISE...GUSTY SOUTHWEST WINDS TO 25 KTS AT TIMES. WINDS AND STORMS TO DIMINISH BY 01Z WEDNESDAY. MAIN COLD FRONT TO SLIDE THROUGH BY 17Z WEDNESDAY. WINDS TO VEER TO THE WEST...WITH STORMS POSSIBLE OVER METRO AREA WITH FRONT. BYRD && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1231 PM CDT Tue Jun 25 2013 .UPDATE... Issued at 1101 AM CDT TUE JUN 25 2013 Thunderstorm activity across eastern Kansas has persisted into the late morning hours, casting showers and cloud cover off to the northeast across our forecast area. While the intensity of the storms has come down over the past couple of hours, they also continue to regenerate on the back edge of the line; which appears due to strong moisture transport across central and eastern Kansas. Short range models other than the RUC are not picking up on this continued development at this time. Focusing on moisture transport, thoughts are that storms could keep redeveloping in eastern Kansas through noon, after which they should decay through the early afternoon as the focus for the transport moves north into eastern Nebraska and Iowa. Cast of showers and isolated embedded thunderstorms are all that is expected from this morning activity. Otherwise, looking at temperatures, have shaved a degree or two off the going highs for today as the cloud cover has been very persistent, but with some potential for the sun to come out by the early to mid-afternoon hours, thoughts are it will get hot and steamy fast. && .SHORT TERM...(Today through Thursday) Issued at 405 AM CDT TUE JUN 25 2013 Challenge for today continues to be chances of precipitation through this afternoon as a nocturnal MCS propagates across central Kansas this morning. The 00Z sounding from KTOP showed ample dry layer such that severe winds were reported with very little convection or rain associated. Upstream of that a short wave trough and low level jet...along with around 8 deg K/KM mid level lapse rates supported upscale growth of an MCS that is producing severe winds as well. This will be the area to monitor as it moves eastward towards the CWA. At this time the storm appears to be splitting with a southern area taking on a more discrete...almost super cellular mode. Given the 0-6km shear in EAX CWA of around 40kts...will have to monitor this activity closely for potential severe threat. The HRRR favors maintaining the area although weakening somewhat after sunrise. The surface winds ahead of this area are decent enough to believe that the boundary layer is well mixed even if the convection itself is elevated. The 500 mb flow will still be at least slightly cyclonic and with the low level moisture and associated CAPE values around 2000 J/KG along with weak short wave ripples in the flow...therefore a chance of convection will last through the day today. As the thermal ridge builds into the area though...the chances for precipitation will decrease with the increased heating of the column late this evening through the remainder of the short term. All models show the upper ridge significantly amplifying over the western half of the US by tomorrow afternoon...so as the nose of the thermal ridge edges into the area...we will have heat indices in the 103F to 106F range on Wednesday. Will not issue a headline at this time because if there is another MCS overnight...some debris cloudiness could limit the temperatures/heat indices. As the ridge amplifies to the west the flow will eventually turn more northwesterly so we will begin to see slight relief by Thursday. Given this flow and cap in place...precipitation chances decrease as well during Thursday. The exception is a possible MCS that may from over eastern Iowa and clip the northeast corner. .LONG TERM...(Friday through Monday) Issued at 405 AM CDT TUE JUN 25 2013 Northwest flow will prevail through this period as a the ridge/trough pattern amplifies across the CONUS. A weak front should have moved through the area by Friday morning with scattered convection lingering into the day. But the bigger effect of the front will be to cool dewpoints down into the lower 60s or even the 50s. As we see a great influence from the eastern trough, temperatures aloft cool down and thickness values decrease substantially. So will also see a nice cool down in the surface temperatures by Saturday into the first half of next week, temperatures look to very close to normal, with highs in the lower to middle 80s. And when combined with the much more comfortable dewpoints, it looks like we`ll see couple days of pleasant summer weather. With regards to precipitation chances, northwest flow is notoriously tricky for timing and placing precipitation chances. At this time, there isn`t a great signal to say that any certain period of time has a greater chance of precipitation than any other period of time. So instead of carrying some mention of precipitation through the bulk of the extended range, have trimmed POPs out until there is a better signal. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon) Issued at 1229 PM CDT TUE JUN 25 2013 VFR conditions are expected to prevail at the terminals over the next 24 hours. What storms persist in the vicinity of the terminals this afternoon are expected to stay in the VFR category. Some potential for more storms to develop later, but confidence is not there to include in the TAF at this time. Otherwise, as the clouds slowly clear this afternoon surface winds will become rather gusty, with sustained speeds from the south above 12 knots, gusting above 25 knots, into the evening. Otherwise, look for winds to veer to the west overnight along with a decrease in speed. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...Cutter SHORT TERM...Adolphson LONG TERM...CDB AVIATION...Cutter
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1102 AM CDT Tue Jun 25 2013 .UPDATE... Issued at 1101 AM CDT TUE JUN 25 2013 Thunderstorm activity across eastern Kansas has persisted into the late morning hours, casting showers and cloud cover off to the northeast across our forecast area. While the intensity of the storms has come down over the past couple of hours, they also continue to regenerate on the back edge of the line; which appears due to strong moisture transport across central and eastern Kansas. Short range models other than the RUC are not picking up on this continued development at this time. Focusing on moisture transport, thoughts are that storms could keep redeveloping in eastern Kansas through noon, after which they should decay through the early afternoon as the focus for the transport moves north into eastern Nebraska and Iowa. Cast of showers and isolated embedded thunderstorms are all that is expected from this morning activity. Otherwise, looking at temperatures, have shaved a degree or two off the going highs for today as the cloud cover has been very persistent, but with some potential for the sun to come out by the early to mid-afternoon hours, thoughts are it will get hot and steamy fast. && .SHORT TERM...(Today through Thursday) Issued at 405 AM CDT TUE JUN 25 2013 Challenge for today continues to be chances of precipitation through this afternoon as a nocturnal MCS propagates across central Kansas this morning. The 00Z sounding from KTOP showed ample dry layer such that severe winds were reported with very little convection or rain associated. Upstream of that a short wave trough and low level jet...along with around 8 deg K/KM mid level lapse rates supported upscale growth of an MCS that is producing severe winds as well. This will be the area to monitor as it moves eastward towards the CWA. At this time the storm appears to be splitting with a southern area taking on a more discrete...almost super cellular mode. Given the 0-6km shear in EAX CWA of around 40kts...will have to monitor this activity closely for potential severe threat. The HRRR favors maintaining the area although weakening somewhat after sunrise. The surface winds ahead of this area are decent enough to believe that the boundary layer is well mixed even if the convection itself is elevated. The 500 mb flow will still be at least slightly cyclonic and with the low level moisture and associated CAPE values around 2000 J/KG along with weak short wave ripples in the flow...therefore a chance of convection will last through the day today. As the thermal ridge builds into the area though...the chances for precipitation will decrease with the increased heating of the column late this evening through the remainder of the short term. All models show the upper ridge significantly amplifying over the western half of the US by tomorrow afternoon...so as the nose of the thermal ridge edges into the area...we will have heat indices in the 103F to 106F range on Wednesday. Will not issue a headline at this time because if there is another MCS overnight...some debris cloudiness could limit the temperatures/heat indices. As the ridge amplifies to the west the flow will eventually turn more northwesterly so we will begin to see slight relief by Thursday. Given this flow and cap in place...precipitation chances decrease as well during Thursday. The exception is a possible MCS that may from over eastern Iowa and clip the northeast corner. .LONG TERM...(Friday through Monday) Issued at 405 AM CDT TUE JUN 25 2013 Northwest flow will prevail through this period as a the ridge/trough pattern amplifies across the CONUS. A weak front should have moved through the area by Friday morning with scattered convection lingering into the day. But the bigger effect of the front will be to cool dewpoints down into the lower 60s or even the 50s. As we see a great influence from the eastern trough, temperatures aloft cool down and thickness values decrease substantially. So will also see a nice cool down in the surface temperatures by Saturday into the first half of next week, temperatures look to very close to normal, with highs in the lower to middle 80s. And when combined with the much more comfortable dewpoints, it looks like we`ll see couple days of pleasant summer weather. With regards to precipitation chances, northwest flow is notoriously tricky for timing and placing precipitation chances. At this time, there isn`t a great signal to say that any certain period of time has a greater chance of precipitation than any other period of time. So instead of carrying some mention of precipitation through the bulk of the extended range, have trimmed POPs out until there is a better signal. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning) Issued at 550 AM CDT TUE JUN 25 2013 Line of storms in eastern Kansas moving towards the east at around 32kts. Main challenge is how much this area of activity will hold together as it reaches the terminals. Given the evolution...believe it has a good chance so going with tempo group. Expect the storms to be fairly weak and bases high so keeping the visibility at 5SM and the CB deck around 8K feet. Will closely monitor as daybreak approaches. Otherwise...winds will also be a challenge today...gusty from the south through the period. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...Cutter SHORT TERM...Adolphson LONG TERM...CDB AVIATION...Adolphson
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
558 AM CDT Tue Jun 25 2013 .SHORT TERM...(Today through Thursday) Issued at 405 AM CDT TUE JUN 25 2013 Challenge for today continues to be chances of precipitation through this afternoon as a nocturnal MCS propagates across central Kansas this morning. The 00Z sounding from KTOP showed ample dry layer such that severe winds were reported with very little convection or rain associated. Upstream of that a short wave trough and low level jet...along with around 8 deg K/KM mid level lapse rates supported upscale growth of an MCS that is producing severe winds as well. This will be the area to monitor as it moves eastward towards the CWA. At this time the storm appears to be splitting with a southern area taking on a more discrete...almost supercellular mode. Given the 0-6km shear in EAX CWA of around 40kts...will have to monitor this activity closely for potential severe threat. The HRRR favors maintaining the area although weakening somewhat after sunrise. The surface winds ahead of this area are decent enough to believe that the boundary layer is well mixed even if the convection itself is elevated. The 500 mb flow will still be at least slightly cyclonic and with the low level moisture and associated CAPE values around 2000 J/KG along with weak short wave ripples in the flow...therefore a chance of convection will last through the day today. As the thermal ridge builds into the area though...the chances for precipitation will decrease with the increased heating of the column late this evening through the remainder of the short term. All models show the upper ridge significantly amplifying over the western half of the US by tomorrow afternoon...so as the nose of the thermal ridge edges into the area...we will have heat indices in the 103F to 106F range on Wednesday. Will not issue a headline at this time because if there is another MCS overnight...some debris cloudiness could limit the temperatures/heat indices. As the ridge amplifies to the west the flow will eventually turn more northwesterly so we will begin to see slight relief by Thursday. Given this flow and cap in place...precipitation chances decrease as well during Thursday. The exception is a possible MCS that may from over eastern Iowa and clip the northeast corner. .LONG TERM...(Friday through Monday) Issued at 405 AM CDT TUE JUN 25 2013 Northwest flow will prevail through this period as a the ridge/trough pattern amplifies across the CONUS. A weak front should have moved through the area by Friday morning with scattered convection lingering into the day. But the bigger effect of the front will be to cool dewpoints down into the lower 60s or even the 50s. As we see a great influence from the eastern trough, temperatures aloft cool down and thickness values decrease substantially. So will also see a nice cool down in the surface temperatures by Saturday into the first half of next week, temperatures look to very close to normal, with highs in the lower to middle 80s. And when combined with the much more comfortable dewpoints, it looks like we`ll see couple days of pleasant summer weather. With regards to precipitation chances, northwest flow is notoriously tricky for timing and placing precipitation chances. At this time, there isn`t a great signal to say that any certain period of time has a greater chance of precipitation than any other period of time. So instead of carrying some mention of precipitation through the bulk of the extended range, have trimmed POPs out until there is a better signal. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning) Issued at 550 AM CDT TUE JUN 25 2013 Line of storms in eastern Kansas moving towards the east at around 32kts. Main challenge is how much this area of activity will hold together as it reaches the terminals. Given the evolution...believe it has a good chance so going with tempo group. Expect the storms to be fairly weak and bases high so keeping the visibility at 5SM and the CB deck around 8K feet. Will closely monitor as daybreak approaches. Otherwise...winds will also be a challenge today...gusty from the south through the period. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ SHORT TERM...Adolphson LONG TERM...CDB AVIATION...Adolphson
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
409 AM CDT Tue Jun 25 2013 .SHORT TERM...(Today through Thursday) Issued at 405 AM CDT TUE JUN 25 2013 Challenge for today continues to be chances of precipitation through this afternoon as a nocturnal MCS propagates across central Kansas this morning. The 00Z sounding from KTOP showed ample dry layer such that severe winds were reported with very little convection or rain associated. Upstream of that a short wave trough and low level jet...along with around 8 deg K/KM mid level lapse rates supported upscale growth of an MCS that is producing severe winds as well. This will be the area to monitor as it moves eastward towards the CWA. At this time the storm appears to be splitting with a southern area taking on a more discrete...almost supercellular mode. Given the 0-6km shear in EAX CWA of around 40kts...will have to monitor this activity closely for potential severe threat. The HRRR favors maintaining the area although weakening somewhat after sunrise. The surface winds ahead of this area are decent enough to believe that the boundary layer is well mixed even if the convection itself is elevated. The 500 mb flow will still be at least slightly cyclonic and with the low level moisture and associated CAPE values around 2000 J/KG along with weak short wave ripples in the flow...therefore a chance of convection will last through the day today. As the thermal ridge builds into the area though...the chances for precipitation will decrease with the increased heating of the column late this evening through the remainder of the short term. All models show the upper ridge significantly amplifying over the western half of the US by tomorrow afternoon...so as the nose of the thermal ridge edges into the area...we will have heat indices in the 103F to 106F range on Wednesday. Will not issue a headline at this time because if there is another MCS overnight...some debris cloudiness could limit the temperatures/heat indices. As the ridge amplifies to the west the flow will eventually turn more northwesterly so we will begin to see slight relief by Thursday. Given this flow and cap in place...precipitation chances decrease as well during Thursday. The exception is a possible MCS that may from over eastern Iowa and clip the northeast corner. .LONG TERM...(Friday through Monday) Issued at 405 AM CDT TUE JUN 25 2013 Northwest flow will prevail through this period as a the ridge/trough pattern amplifies across the CONUS. A weak front should have moved through the area by Friday morning with scattered convection lingering into the day. But the bigger effect of the front will be to cool dewpoints down into the lower 60s or even the 50s. As we see a great influence from the eastern trough, temperatures aloft cool down and thickness values decrease substantially. So will also see a nice cool down in the surface temperatures by Saturday into the first half of next week, temperatures look to very close to normal, with highs in the lower to middle 80s. And when combined with the much more comfortable dewpoints, it looks like we`ll see couple days of pleasant summer weather. With regards to precipitation chances, northwest flow is notoriously tricky for timing and placing precipitation chances. At this time, there isn`t a great signal to say that any certain period of time has a greater chance of precipitation than any other period of time. So instead of carrying some mention of precipitation through the bulk of the extended range, have trimmed POPs out until there is a better signal. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday Night) Issued at 1159 PM CDT MON JUN 24 2013 Convection over KS continues to sputter/fizzle as it moves east across the MO/KS state line. While short range models have not captured the rain area very well they have been spot on with respect to a lack of how much reaches the ground on the MO side. Cloud bases are quite high and this brings up the potential for gusty winds to 40kts should any convective cell dissipate as it passes near a terminal. Current indications are KSTJ has best chance of hearing thunder vs the two KC terminals and TAFs have been adjusted accordingly. Will amend forecasts should the KS convection cycle up but expect best rain chances overnight will be over northwest MO from KSTJ northward. Low confidence on convection on Tuesday due to a lack of a discernible boundary and forcing mechanism. Rain chances will be left to mesoscale processes/systems which are best left to later forecasts. Main theme will be the strong and gusty southerly winds. May see an occasional gust overnight but winds will become strongest by mid Tuesday morning and remain that way into the evening due to a strong pressure gradient and efficient momentum transfer of a stout low level jet. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ SHORT TERM...Adolphson LONG TERM...CDB AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1206 AM CDT Tue Jun 25 2013 .UPDATE... Issued at 1052 PM CDT MON JUN 24 2013 Neither the short range convection allowing models nor 00z NAM have much of a clue to the ongoing convection from southwest KS through west central MO. Activity appears to be aligning itself wsw-ene along a weak area of frontogenesis within the h8-h7 layer best depicted by the 02z RAP. The southerly h8 winds of 40-45kts is advecting ample moisture/instability across this boundary and with CIN values increasing since sunset this now supports elevated vs surface based convection. While the initial activity into our western counties tends to weaken/dissipate believe convection further upstream over KS will stand a better chance of surviving as it spreads eastward overnight and thus chance PoPs are warranted for the far west central and northwest portions of the CWA. && .SHORT TERM...(This Evening through Tuesday Night) Issued at 355 PM CDT MON JUN 24 2013 Main concern will be with potential for convection again tonight and then increasing heat conditions Tuesday. Latest HRRR model shows shortwave trough in synoptic flow to hold together as it moves into eastern Kansas. Dynamics are fairly weak as this is just a ripple in the nearly zonal flow over the region. However...there is some modest instability and potential for a decent LLJ late tonight....so another nocturnal MCS could move through...especially in northern zones where mid level lapse rates favor better instability. On Tuesday...there still is a chance in the afternoon in the northern zones for some convection to fire as yet another very weak short wave trough moves through. Also of concern is what might be left over in terms of outflow boundaries from any activity tonight. Therefore...will keep a chance in the northern zones for tomorrow. Meanwhile the thermal ridge begins to build to the west with 850mb temperatures into the middle and upper 20s deg C in western and central Kansas. As this thermal ridge moves towards the area...we will see heat indices begin to edge up to low 100s. Will not issue advisory for Tuesday but have mentioned it in the hazardous weather outlook. Tuesday night...yet another chance for some nocturnal MCS activity mainly in the northeastern zones as the thermal ridge axis moves over the western areas and should limit convection there. .LONG TERM...(Wednesday through Monday) Issued at 355 PM CDT MON JUN 24 2013 Beginning in the middle of the work week, the flattened zonal flow across the nation will begin to amplify as the prevailing westerlies begin to buckle across the U.S.A./Canadian border. The buckling in the flow will be lead by a weak shortwave Wednesday, with our region quickly finding itself in the the northwest flow as the ridge axis of the amplifying ridge pops up to to our west. However, as the weekend arrives the trough across the Great Lakes will gather some energy, expanding enough to possibly but much of our forecast area on the cool side of the still prevailing northwest flow. The pattern for the week will dictate hot and humid conditions through the middle of the work week, with Wednesday and Thursday being particularly muggy and troublesome. Dew points will be critical mid-week on determining the need for a heat advisory as heat indices will be ranging in the low 100s. Currently, forecast numbers are coming up just shy of criteria, though this currently looks due to the fact that afternoon dew points will likely mix out a little as the hot air advecting in aloft from the southwest will also be a bit dry. By Friday...temperatures are expected to back off a little from the hot and humid readings of the previous few days as the trough over the Great Lakes begins to dominate the eastern CONUS. Readings for Friday will still reach in the 90s, but the humidity wont be as bad; and for the weekend temperatures should range through the 80s. As for precipitation, only true potential for more than isolated storms looks to be focused on Thursday night into Friday morning as the edge of the Great Lakes trough begins pushing back to the southwest. Have kept PoPs in the chance category owing to the vagaries of forecast timing in a northwest flow. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday Night) Issued at 1159 PM CDT MON JUN 24 2013 Convection over KS continues to sputter/fizzle as it moves east across the MO/KS state line. While short range models have not captured the rain area very well they have been spot on with respect to a lack of how much reaches the ground on the MO side. Cloud bases are quite high and this brings up the potential for gusty winds to 40kts should any convective cell dissipate as it passes near a terminal. Current indications are KSTJ has best chance of hearing thunder vs the two KC terminals and TAFs have been adjusted accordingly. Will amend forecasts should the KS convection cycle up but expect best rain chances overnight will be over northwest MO from KSTJ northward. Low confidence on convection on Tuesday due to a lack of a discernible boundary and forcing mechanism. Rain chances will be left to mesoscale processes/systems which are best left to later forecasts. Main theme will be the strong and gusty southerly winds. May see an occasional gust overnight but winds will become strongest by mid Tuesday morning and remain that way into the evening due to a strong pressure gradient and efficient momentum transfer of a stout low level jet. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...MJ SHORT TERM...Adolphson/73 LONG TERM...Cutter AVIATION...MJ
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
255 PM MDT Tue Jun 25 2013 .DISCUSSION... Tonight through Thursday...Southwest flow aloft continues to bring moisture and instability to the area. Convective activity is slow to develop this afternoon but a large plume of moisture is now moving into western Montana with scattered showers and thunderstorms developing. RUC analysis continues to show precipitation developing over the area this evening and development will be aided by a jet streak moving across the area. Have painted low pops across the county warning area until midnight. Any thunderstorms that develop will likely be high based with gusty winds being the main threat. Convective activity should generally end by midnight. Heights begin to rise Wednesday though isolated showers are possible in a swath across central Montana Wednesday morning due to the proximity of the jet streak. Heights continue to rise Wednesday afternoon through Thursday resulting in dry and warmer conditions. The strong westerly flow aloft Wednesday, combined with warmer temperatures, will allow the atmosphere to effectively mix down and gusty winds will result during the afternoon. Temperatures will be near seasonal averages Wednesday but will warm through the remainder of the week. Emanuel Thursday night through Tuesday...Medium range models remain in good agreement for the first few days of the forecast period. An upper level ridge over the western U.S. will strengthen over the northern Rockies for much warmer temperatures for Friday and Saturday. Model solutions diverge Saturday night as the GFS bring shortwave energy and an upper level jet through the northern Rockies for a slight chance of thunderstorms while the ECMWF keeps a dry and stable airmass in place. The upper wave depicted in the GFS will continue to affect central Montana through Sunday evening but the models come back into agreement by Monday as the ridge axis regresses into the Pacific northwest and puts Montana under a north to northwest flow aloft with unsettled but continued warm conditions into Tuesday. mpj && .AVIATION... Updated 1757Z. VFR conditions will prevail through the period. SCT low clouds viewed on satellite imagery and web cams at all terminals Tuesday afternoon. Strong southwest wind gusts up to 30kts will continue through evening. Winds will weaken overnight but then strengthen again Wednesday morning. A weak shortwave trough will bring scattered showers to southwest MT through 03Z this evening so have added VCSH to KBZN/KHLN. A weak frontal boundary moves through western MT early Wednesday around 26/15Z with low confidence for additional rainshowers near KGTF/KHLN/KLWT. Therefore, cigs are retained through the period but excluded Wednesday morning rain showers from the TAFS pending later guidance. Nutter && .PRELIMINARY POINT TEMPS/POPS... GTF 52 77 53 82 / 20 20 10 0 CTB 49 74 49 79 / 20 10 10 0 HLN 53 77 53 83 / 20 10 10 0 BZN 50 80 48 86 / 20 10 10 0 WEY 40 72 39 80 / 20 20 10 0 DLN 48 77 48 84 / 30 10 10 0 HVR 54 81 54 84 / 20 10 10 0 LWT 50 76 50 80 / 20 10 10 0 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1115 PM EDT WED JUN 26 2013 .SYNOPSIS... THE WARM AND HUMID WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY THROUGH THE WEEKEND RIGHT INTO NEXT WEEK...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. A MORE WIDESPREAD HEAVY RAINFALL IS EXPECTED THURSDAY NIGHT INTO FRIDAY WHEN AN AREA OF LOW PRESSURE MOVES THROUGH THE REGION. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 1020 PM EDT WEDNESDAY...WEAK AREA OF SFC LOW PRESSURE NEAR MONTREAL HAS ALLOWED SFC WINDS ACROSS NORTHERN VT TO BACK TO SOUTHEAST WITH ISOLATED THUNDERSTORMS APPROACHING THE NORTHERN END OF LAKE CHAMPLAIN. THE STORMS ARE RIDING ALONG A NARROW ZONE OF WEAK SFC CONVERGENCE LOCATED ALONG THE CANADIAN BORDER...ON THE SOUTHERN END OF A UPPER-LEVEL TROUGH ENTERING INTO EASTERN QUEBEC. IT`S AN OTHERWISE WEAKLY UNSTABLE AIRMASS /CAPES OF AROUND 800 J/KG OR LESS BASED ON RECENT LAPS & RAP ANALYSES/...AND SO EXPECT THE STORMS TO DIMINISHING THROUGH THE REST OF THE OVERNIGHT. SO HAVE MENTIONED ISOLATED SHOWERS AFTER MIDNIGHT FOR THE NORTHEAST KINGDOM WITH THE REST OF THE NORTH COUNTRY BEING DRY. HAVE KEPT PATCHY FOG GOING AFTER MIDNIGHT. NOTICING THAT SPRINGFIELD VT AND GLENS FALLS NY ALREADY STARTING TO SEE MIST DEVELOP AND EXPECT AREAS OF PATCHY FOG TO FILL IN OVERNIGHT. TWEAKED LOW TEMPERATURES UP SEVERAL DEGREES ESPECIALLY IN THE ADIRONDACKS. MOST OF THE SHORT-RANGE GUIDANCE SHOWS LOWS THERE IN THE UPPER 50S WHICH IS TOO LOW AS DEWPOINTS ARE STILL IN THE MID 60S AND WITH NO CHANGE IN AIRMASS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 442 PM EDT WEDNESDAY...EXPECT IT TO REMAIN DRY THURSDAY MORNING...BUT CHANCES FOR SOME SHOWERS AND THUNDERSTORMS INCREASE DURING THE AFTERNOON ONCE AGAIN AS TEMPS WARM INTO THE LOWER 80S AND ATMOSPHERE BECOMES MARGINALLY UNSTABLE WITH SBCAPES FORECAST TO REACH 1000-1500 J/KG. BEST CHANCE WILL BE OVER SOUTHERN SECTIONS...ESPECIALLY OVER THE HIGHER TERRAIN. MORE WIDESPREAD RAINY CONDITIONS DEVELOP THURSDAY NIGHT DUE TO A VIGOROUS SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW PRESSURE...WHICH WILL BE LIFTING NORTHEAST INTO THE REGION THURSDAY NIGHT. THIS HAS PROMPTED ISSUANCE OF A FLOOD WATCH FOR JUST ABOUT THE ENTIRE FORECAST AREA FOR THURSDAY NIGHT/FRIDAY. PRECIPITABLE WATER VALUES EXPECTED TO CLIMB TO BETWEEN 1.5 AND 2 INCHES...SUPPORTING THREAT OF HEAVY RAIN AS THE LOW MOVES INTO THE AREA. RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM 1.5 TO 2.5 INCHES ACROSS THE REGION WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE...ESPECIALLY ALONG S-SE FACING PORTIONS OF ADIRONDACK AND GREEN MOUNTAINS. GIVEN THE SATURATED CONDITIONS FROM EXCESSIVE RAINFALL THIS MONTH...THIS WILL BE ENOUGH TO RAISE FLOOD CONCERNS NOT ONLY FOR SMALLER STREAMS BUT THE MAIN STEM RIVERS AS WELL. (SEE HYDRO SECTION BELOW). RAIN WILL TAPER TO SCATTERED SHOWERS FRIDAY NIGHT AS SURFACE LOW LIFTS TO THE NORTH. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 155 PM EDT WEDNESDAY...CONTINUED WET...ACTIVE/UNSETTLED WEATHER PATTERN CONTINUES WITH GOOD MODEL AGREEMENT AS A BERMUDA HIGH LIKE FEATURE OFF THE SE CONUS COAST REMAINS IN PLACE. SEVERAL MID/UPPER LVL SHORTWAVES WILL MOVE THROUGH THE TROUGH STRETCHING ACROSS THE CENTRAL PLAINS/OHIO VALLEY. THE COMBINATION OF DEEP TROPICAL ADVECTION FROM CONTINUOUS SW FLW ALOFT AND SEVERAL EMBEDDED 5H VORTS WILL KEEP THREAT OF SHOWERS AND TSTMS INTO EARLY NEXT WK. CONDITIONS WILL BE FAVORABLE FOR ADDITIONAL LOCALIZED HEAVY RAINFALL AT TIMES WITHIN AFTN/EVENING SHOWERS/TSTMS...WHEN SFC HEATING/INSTABILITY IS THE GREATEST. GIVEN THE RECENT RAINFALL AND SATURATED SOILS...THE POTENTIAL FOR ADDITIONAL FLOODING FROM HEAVY RAINFALL WILL NEED TO BE WATCHED CLOSELY. MAX TEMPS WILL BE IN THE 70S TO L/M80S AND OVERNIGHT CONTINUES TO BE MUGGY WITH MIN TEMPS IN THE M50S TO M60S. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... THROUGH 00Z FRIDAY...ISO/SCT THUNDERSTORMS REMAIN CONFINED NORTH OF THE BORDER AND ARE QUICKLY RAINING THEMSELVES OUT...SO HAVE REMOVED MENTION VCTS. OVERALL EXPECT CONTINUED VFR THROUGH 03Z OR SO WITH DEVELOPING IFR/LIFR IN MIST/FOG FOR MOST OF THE TAFS. AS HAS BEEN THE CASE FOR THE PAST COUPLE DAYS MOST LOCATIONS RECEIVED SOME RAINFALL TODAY...AND WHEN COMBINED WITH LIGHT SFC WINDS PREDICTED TONIGHT THAT WILL ENHANCE THE CHANCES FOR MIST/FOG DEVELOPMENT. ONCE FOG LIFTS EARLY THURSDAY AM CONDITIONS BECOME VFR AT ALL TAF SITES. HOWEVER UNSETTLED PATTERN CONTINUES WITH INITIALLY TERRAIN- DRIVEN ISO/SCT SHOWERS/STORMS. CEILINGS GRADUALLY LOWER THROUGH THE REST OF THE TAF PERIOD AHEAD OF THE ONSET OF MORE WIDESPREAD SHOWERS OR STORMS /EXPECTED TO TAKE PLACE AFTER 00Z FRIDAY/. WINDS WILL BE BECOMING SOUTHEAST/SOUTH UNDER 10 KTS. EXCEPTION IS AT MSS WHERE INITIALLY VARIABLE WINDS NORTHEAST UNDER 10KTS THURSDAY AFTERNOON. OUTLOOK 00Z FRIDAY THROUGH MONDAY...UNSETTLE PATTERN CONTINUES AS THE DEVELOPMENT OF A DEEP TROF ACROSS THE EASTERN CONUS WILL PRODUCE NUMEROUS ROUNDS OF SHOWERS/STORMS...EACH AFTN/EVENING...WITH OCCASIONAL MVFR/IFR CONDITIONS POSSIBLE IN THE HEAVIER STORMS. OVERNIGHT/EARLY MORNING FOG/BR WITH MVFR/IFR WILL BE POSSIBLE MAINLY AT KMPV/KSLK...ESPECIALLY IF RAIN OCCURS THE PREVIOUS AFTN. IN ADDITION...SOME GUSTY SOUTH TO SOUTHEAST WINDS WILL BE POSSIBLE...ESPECIALLY AT RUTLAND ON FRIDAY AFTN...WITH LOCALIZED AREAS OF WIND SHEAR AND TURBULENCE POSSIBLE. && .HYDROLOGY... AS OF 425 PM EDT WEDNESDAY...A BAND OF MODERATE RAINFALL MOVED OUT OF NORTHERN NEW YORK AND TRAVELED ACROSS VERMONT DURING THE DAY. MOST RAINFALL AMOUNTS WERE A HALF TO QUARTER INCH. THIS WILL SERVE TO KEEP SOILS SATURATED AND RIVERS AND STREAMS RUNNING WELL ABOVE NORMAL. ADDITIONAL HEAVY RAINFALL IS LIKELY THURSDAY NIGHT THROUGH FRIDAY AND POSSIBLY INTO SATURDAY...WITH AN ADDITIONAL 1 TO 3 INCHES OF RAIN LIKELY BY SATURDAY ACROSS MOST OF THE NORTH COUNTRY. IF THE OVER TWO INCHES OF RAIN MATERIALISES...FLOODING IS LIKELY. THE GROUND IS SO SATURATED IS SIMPLY CANNOT HANDLE ADDITIONAL RAINFALL...AND ANY RAIN WILL RUN OFF IMMEDIATELY. ANY PLACE THAT RECEIVES AN INCH OF RAIN IN HALF AN HOUR...OR 1.5 INCH IN AN HOUR WILL LIKELY SEE FLOODING. IN ADDITION...MANY AREAS SINCE LATE MAY HAVE EXPERIENCED FLOODING OF SOME FORM OR ANOTHER...AND THOSE LOCATIONS WILL REMAIN PARTICULARLY VULNERABLE TO RENEWED FLOODING. A FLOOD WATCH WAS ISSUED BASED ON THE SYNOPTIC SCALE RAINFALL EVENT...HOWEVER FLASH FLOODING AT THE ONSET THURSDAY NIGHT CANNOT BE RULED OUT. THE EVENT IS EXPECTED TO TRANSITION INTO MORE WIDESPREAD MAIN-STEM RIVER FLOODING...THUS THE ISSUANCE OF THE FLOOD WATCH RATHER THAN FLASH FLOOD WATCH. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FLOOD WATCH FROM THURSDAY EVENING THROUGH FRIDAY EVENING FOR VTZ002>012-016>019. NY...FLOOD WATCH FROM THURSDAY EVENING THROUGH FRIDAY EVENING FOR NYZ028>031-034-035. && $$ SYNOPSIS...RJS NEAR TERM...RJS/LOCONTO SHORT TERM...RJS LONG TERM...KGM/TABER AVIATION...KGM/LOCONTO HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1020 PM EDT WED JUN 26 2013 .SYNOPSIS... THE WARM AND HUMID WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY THROUGH THE WEEKEND RIGHT INTO NEXT WEEK...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. A MORE WIDESPREAD HEAVY RAINFALL IS EXPECTED THURSDAY NIGHT INTO FRIDAY WHEN AN AREA OF LOW PRESSURE MOVES THROUGH THE REGION. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 1020 PM EDT WEDNESDAY...WEAK AREA OF SFC LOW PRESSURE NEAR MONTREAL HAS ALLOWED SFC WINDS ACROSS NORTHERN VT TO BACK TO SOUTHEAST WITH ISOLATED THUNDERSTORMS APPROACHING THE NORTHERN END OF LAKE CHAMPLAIN. THE STORMS ARE RIDING ALONG A NARROW ZONE OF WEAK SFC CONVERGENCE LOCATED ALONG THE CANADIAN BORDER...ON THE SOUTHERN END OF A UPPER-LEVEL TROUGH ENTERING INTO EASTERN QUEBEC. IT`S AN OTHERWISE WEAKLY UNSTABLE AIRMASS /CAPES OF AROUND 800 J/KG OR LESS BASED ON RECENT LAPS & RAP ANALYSES/...AND SO EXPECT THE STORMS TO DIMINISHING THROUGH THE REST OF THE OVERNIGHT. SO HAVE MENTIONED ISOLATED SHOWERS AFTER MIDNIGHT FOR THE NORTHEAST KINGDOM WITH THE REST OF THE NORTH COUNTRY BEING DRY. HAVE KEPT PATCHY FOG GOING AFTER MIDNIGHT. NOTICING THAT SPRINGFIELD VT AND GLENS FALLS NY ALREADY STARTING TO SEE MIST DEVELOP AND EXPECT AREAS OF PATCHY FOG TO FILL IN OVERNIGHT. TWEAKED LOW TEMPERATURES UP SEVERAL DEGREES ESPECIALLY IN THE ADIRONDACKS. MOST OF THE SHORT-RANGE GUIDANCE SHOWS LOWS THERE IN THE UPPER 50S WHICH IS TOO LOW AS DEWPOINTS ARE STILL IN THE MID 60S AND WITH NO CHANGE IN AIRMASS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 442 PM EDT WEDNESDAY...EXPECT IT TO REMAIN DRY THURSDAY MORNING...BUT CHANCES FOR SOME SHOWERS AND THUNDERSTORMS INCREASE DURING THE AFTERNOON ONCE AGAIN AS TEMPS WARM INTO THE LOWER 80S AND ATMOSPHERE BECOMES MARGINALLY UNSTABLE WITH SBCAPES FORECAST TO REACH 1000-1500 J/KG. BEST CHANCE WILL BE OVER SOUTHERN SECTIONS...ESPECIALLY OVER THE HIGHER TERRAIN. MORE WIDESPREAD RAINY CONDITIONS DEVELOP THURSDAY NIGHT DUE TO A VIGOROUS SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW PRESSURE...WHICH WILL BE LIFTING NORTHEAST INTO THE REGION THURSDAY NIGHT. THIS HAS PROMPTED ISSUANCE OF A FLOOD WATCH FOR JUST ABOUT THE ENTIRE FORECAST AREA FOR THURSDAY NIGHT/FRIDAY. PRECIPITABLE WATER VALUES EXPECTED TO CLIMB TO BETWEEN 1.5 AND 2 INCHES...SUPPORTING THREAT OF HEAVY RAIN AS THE LOW MOVES INTO THE AREA. RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM 1.5 TO 2.5 INCHES ACROSS THE REGION WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE...ESPECIALLY ALONG S-SE FACING PORTIONS OF ADIRONDACK AND GREEN MOUNTAINS. GIVEN THE SATURATED CONDITIONS FROM EXCESSIVE RAINFALL THIS MONTH...THIS WILL BE ENOUGH TO RAISE FLOOD CONCERNS NOT ONLY FOR SMALLER STREAMS BUT THE MAIN STEM RIVERS AS WELL. (SEE HYDRO SECTION BELOW). RAIN WILL TAPER TO SCATTERED SHOWERS FRIDAY NIGHT AS SURFACE LOW LIFTS TO THE NORTH. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 155 PM EDT WEDNESDAY...CONTINUED WET...ACTIVE/UNSETTLED WEATHER PATTERN CONTINUES WITH GOOD MODEL AGREEMENT AS A BERMUDA HIGH LIKE FEATURE OFF THE SE CONUS COAST REMAINS IN PLACE. SEVERAL MID/UPPER LVL SHORTWAVES WILL MOVE THROUGH THE TROUGH STRETCHING ACROSS THE CENTRAL PLAINS/OHIO VALLEY. THE COMBINATION OF DEEP TROPICAL ADVECTION FROM CONTINUOUS SW FLW ALOFT AND SEVERAL EMBEDDED 5H VORTS WILL KEEP THREAT OF SHOWERS AND TSTMS INTO EARLY NEXT WK. CONDITIONS WILL BE FAVORABLE FOR ADDITIONAL LOCALIZED HEAVY RAINFALL AT TIMES WITHIN AFTN/EVENING SHOWERS/TSTMS...WHEN SFC HEATING/INSTABILITY IS THE GREATEST. GIVEN THE RECENT RAINFALL AND SATURATED SOILS...THE POTENTIAL FOR ADDITIONAL FLOODING FROM HEAVY RAINFALL WILL NEED TO BE WATCHED CLOSELY. MAX TEMPS WILL BE IN THE 70S TO L/M80S AND OVERNIGHT CONTINUES TO BE MUGGY WITH MIN TEMPS IN THE M50S TO M60S. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... THROUGH 00Z FRIDAY...ISO/SCT THUNDERSTORMS REMAIN CONFINED NORTH OF THE BORDER AND ARE QUICKLY RAINING THEMSELVES OUT...SO HAVE REMOVED MENTION VCTS. OVERALL EXPECT CONTINUED VFR THROUGH 03Z OR SO WITH DEVELOPING IFR/LIFR IN MIST/FOG FOR MOST OF THE TAFS. AS HAS BEEN THE CASE FOR THE PAST COUPLE DAYS MOST LOCATIONS RECEIVED SOME RAINFALL TODAY...AND WHEN COMBINED WITH LIGHT SFC WINDS PREDICTED TONIGHT THAT WILL ENHANCE THE CHANCES FOR MIST/FOG DEVELOPMENT. ONCE FOG LIFTS EARLY THURSDAY AM CONDITIONS BECOME VFR AT ALL TAF SITES. HOWEVER UNSETTLED PATTERN CONTINUES WITH INITIALLY TERRAIN- DRIVEN ISO/SCT SHOWERS/STORMS. CEILINGS GRADUALLY LOWER THROUGH THE REST OF THE TAF PERIOD AHEAD OF THE ONSET OF MORE WIDESPREAD SHOWERS OR STORMS /EXPECTED TO TAKE PLACE AFTER 00Z FRIDAY/. WINDS WILL BE BECOMING SOUTHEAST/SOUTH UNDER 10 KTS. EXCEPTION IS AT MSS WHERE INITIALLY VARIABLE WINDS NORTHEAST UNDER 10KTS THURSDAY AFTERNOON. OUTLOOK 00Z FRIDAY THROUGH MONDAY...UNSETTLE PATTERN CONTINUES AS THE DEVELOPMENT OF A DEEP TROF ACROSS THE EASTERN CONUS WILL PRODUCE NUMEROUS ROUNDS OF SHOWERS/STORMS...EACH AFTN/EVENING...WITH OCCASIONAL MVFR/IFR CONDITIONS POSSIBLE IN THE HEAVIER STORMS. OVERNIGHT/EARLY MORNING FOG/BR WITH MVFR/IFR WILL BE POSSIBLE MAINLY AT KMPV/KSLK...ESPECIALLY IF RAIN OCCURS THE PREVIOUS AFTN. IN ADDITION...SOME GUSTY SOUTH TO SOUTHEAST WINDS WILL BE POSSIBLE...ESPECIALLY AT RUTLAND ON FRIDAY AFTN...WITH LOCALIZED AREAS OF WIND SHEAR AND TURBULENCE POSSIBLE. && .HYDROLOGY... AS OF 425 PM EDT WEDNESDAY...A BAND OF MODERATE RAINFALL MOVED OUT OF NORTHERN NEW YORK AND TRAVELED ACROSS VERMONT DURING THE DAY. MOST RAINFALL AMOUNTS WERE A HALF TO QUARTER INCH. THIS WILL SERVE TO KEEP SOILS SATURATED AND RIVERS AND STREAMS RUNNING WELL ABOVE NORMAL. ADDITIONAL HEAVY RAINFALL IS LIKELY THURSDAY NIGHT THROUGH FRIDAY AND POSSIBLY INTO SATURDAY...WITH AN ADDITIONAL 1 TO 3 INCHES OF RAIN LIKELY BY SATURDAY ACROSS MOST OF THE NORTH COUNTRY. IF THE OVER TWO INCHES OF RAIN MATERIALISES...FLOODING IS LIKELY. THE GROUND IS SO SATURATED IS SIMPLY CANNOT HANDLE ADDITIONAL RAINFALL...AND ANY RAIN WILL RUN OFF IMMEDIATELY. ANY PLACE THAT RECEIVES AN INCH OF RAIN IN HALF AN HOUR...OR 1.5 INCH IN AN HOUR WILL LIKELY SEE FLOODING. IN ADDITION...MANY AREAS SINCE LATE MAY HAVE EXPERIENCED FLOODING OF SOME FORM OR ANOTHER...AND THOSE LOCATIONS WILL REMAIN PARTICULARLY VULNERABLE TO RENEWED FLOODING. A FLOOD WATCH WAS ISSUED BASED ON THE SYNOPTIC SCALE RAINFALL EVENT...HOWEVER FLASH FLOODING AT THE ONSET THURSDAY NIGHT CANNOT BE RULED OUT. THE EVENT IS EXPECTED TO TRANSITION INTO MORE WIDESPREAD MAIN-STEM RIVER FLOODING...THUS THE ISSUANCE OF THE FLOOD WATCH RATHER THAN FLASH FLOOD WATCH. && .EQUIPMENT... AS OF 425 PM EDT WEDNESDAY...METAR OBSERVATIONS AT RUTLAND- SOUTHERN VERMONT REGIONAL AIRPORT (KRUT) HAVE RETURNED AS OF LATE WEDNESDAY AFTERNOON. THE KCXX /COLCHESTER VERMONT/ WSR-88D IS OUT OF SERVICE FOR REPAIRS. PARTS ARE EXPECTED TO ARRIVE ON THURSDAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FLOOD WATCH FROM THURSDAY EVENING THROUGH FRIDAY EVENING FOR VTZ002>012-016>019. NY...FLOOD WATCH FROM THURSDAY EVENING THROUGH FRIDAY EVENING FOR NYZ028>031-034-035. && $$ SYNOPSIS...RJS NEAR TERM...RJS/LOCONTO SHORT TERM...RJS LONG TERM...KGM/TABER AVIATION...KGM/LOCONTO HYDROLOGY... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
700 AM EDT TUE JUN 25 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE CENTERED WELL OFFSHORE WILL REMAIN IN PLACE INTO THE WEEKEND...WHILE WEAK UPPER IMPULSES TRACK JUST NORTH OF THE AREA. THIS WILL CONTINUE THE WARM AND HUMID CONDITIONS ACROSS THE AREA...WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 615 AM TUESDAY...MODELS INDICATE RATHER LOW AMPLITUDE IE. FLAT MID AND UPPER LEVEL RIDGING EXTENDING NW ACROSS THE AREA FROM THE BASE OR CENTER LOCATED OVER THE OFFSHORE WATERS OFF THE SE U.S. COAST. MODELS INDICATE WEAK MID-LEVEL TROFFINESS ACROSS THE SE STATES WHICH WILL LIKELY BE ENOUGH TO AID IN FIRING DIURNALLY DRIVEN CONVECTION. THE SEA BREEZE AND OUTFLOWS WILL BE THE OTHER AIDS TO KEEP CONVECTION FIRING THROUGHOUT THE DAY AND INTO THE EVENING. LATEST HRRR DOES INDICATE CONVECTION TO FIRE AROUND SUNRISE BUT NOT BOUGHT ON ITS WIDESPREAD COVERAGE THAT EARLY. THINKING IS SOMEWHAT SIMILAR TO MONDAY CONCERNING POPS IN THE 30-50 PERCENT RANGE BY MID MORNING AND LASTING THROUGH MID- EVENING. NAMBUFR SOUNDINGS INDICATE 1.75 TO 2.00 PRECIPITABLE WATERS ACROSS THE FA ONCE AGAIN. THEREFORE...THE MAIN THREAT FROM TODAYS CONVECTION WILL BE THE HEAVY DOWNPOURS ACROSS GROUNDS THAT HAVE BECOME SOMEWHAT SATURATED FROM THE RECENT RAINS OF THE PAST FEW DAYS. WILL ONCE AGAIN HAVE A LOW DIURNAL RANGE BETWEEN MAX AND MIN TEMPS DUE TO CLOUDS AND THE PCPN THREAT. STAYED ON THE LOWER SIDE OF MODEL MOS GUIDANCE FOR TODAYS MAXES...AND THE HIGHER SIDE OF MODEL MOS FOR TONIGHTS LOWS. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 AM TUESDAY...PERSISTENCE THE RULE FOR THE SHORT TERM AS SUMMERTIME PATTERN REMAINS IN PLACE WITH BERMUDA HIGH OFFSHORE AND FLAT RIDGING CONTINUING ALOFT. THIS CREATES A WARM...HUMID...AND ACTIVE PATTERN AS TEMPS RISE INTO THE LOW 90S AWAY FROM THE COAST...WITH LOWS FALLING ONLY INTO THE LOW 70S. HOWEVER...THERE WILL LIKELY BE CONSIDERABLE VARIABILITY EACH DAY AS CONVECTION LOOKS TO BE SCATTERED-TO-WIDESPREAD ACROSS THE AREA. IN ADDITION TO THE FLAT 5H RIDGING WHICH SLOWLY BEGINS TO BREAK DOWN...A WEAK VORT WILL CROSS OVERHEAD ON WEDNESDAY. TIMING THIS FEATURE IS STILL UNCERTAIN...AND THERE WILL BE A RACE BETWEEN SUBSIDENCE BEHIND THE VORT...AND AFTN INSTABILITY. ASSUMING THE VORT MOVES OFFSHORE EARLY...WILL CAP POP AT LOW-CHC...AND WEDNESDAY MAY BE THE DRIEST DAY OF THE WEEK. BY THURSDAY...MID LEVEL LAPSE RATES STEEPEN CONSIDERABLY AND MORE WIDESPREAD CONVECTION IS ANTICIPATED IN A CONTINUED HIGHLY UNSTABLE ENVIRONMENT. WHILE SEVERE CONVECTION LOOKS UNLIKELY...OR ISOLATED AT WORST...HEAVY RAIN AND FLOODING WILL CONTINUE TO BE A CONCERN IN A SATURATED COLUMN. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 300 AM TUESDAY...BIG CHANGES TO THE UPPER PATTERN DURING THE EXTENDED...BUT LITTLE SENSIBLE WEATHER DIFFERENCES TO BE EXPERIENCED ACROSS THE EASTERN CAROLINAS. 600DM RIDGE AT 5H EXPANDS ACROSS THE SW...CENTERED OVER THE 4-CORNERS REGION...FORCING A DEEPENING EASTERN CONUS TROUGH. LONGWAVE PATTERN BECOMES INCREASINGLY AMPLIFIED...WITH THE EASTERN TROUGH BOOKENDED BY LARGE RIDGES BOTH UPSTREAM AND DOWNSTREAM. THIS CAUSES THE LONGITUDINAL FLOW TO COME TO A SLOW/HALT...AND THE EASTERN TROUGH WILL PERSIST THROUGH THE EXTENDED. HOWEVER...WITH TROUGH AXIS REMAINING WELL WEST OF THE AREA...DEEP SW FLOW WILL ADVECT TREMENDOUS MOISTURE AGAIN INTO THE COLUMN...EVEN AS BERMUDA HIGH SLOWLY BREAKS DOWN. THIS SUPPORTS THE POTENTIAL FOR A VERY WET PERIOD RETURNING TO THE CAROLINAS...AND SAT-MON COULD BE EVEN WETTER THAN THE PAST FEW DAYS HAVE BEEN. WPC QPF GRAPHICS SUPPORT THIS...AS CHANNELED MOISTURE TAPS THE GULF OF MEXICO AND STREAMS RIGHT INTO THE AREA. FOR NOW WILL CONTINUE CHC POP THROUGH THE PERIOD WITH HIGHS RIGHT AROUND CLIMO AND LOWS JUST A BIT ABOVE. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...SOME LIGHT CONVECTION HAS POPPED UP IN BRUNSWICK COUNTY...SOME SORT OF A WEAK CONVERGENCE BOUNDARY. THE LFC IS A BIT HIGHER TODAY...NEVERTHELESS SOME SHOWERS MAY AFFECT ILM FOR THE FIRST HOUR OR TWO. LOOK FOR SOME INTERMITTENT IFR CEILINGS AT FLO FOR THE FIRST HOUR...THEN LIFTING TO MVFR OR SCATTERING. LATER TODAY...EXPECT ACTIVITY ALONG THE SEA BREEZE BOUNDARY...WITH ISOLATED CONVECTION INLAND LATER THIS AFTERNOON. MOST OF THE CONVECTION WILL END BY 22Z...WITH MORE MID AND HIGH CLOUDS OVERNIGHT. EXTENDED OUTLOOK...ISO/SCT AFTERNOON SHOWERS AND T-STORMS THROUGH SATURDAY WITH LOCALIZED PERIODS OF MVFR/IFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 615 AM TUESDAY...WEAK RIDGING SFC AND ALOFT WILL CONTINUE ITS HOLD ACROSS THE AREA WATERS THIS NEAR TERM PERIOD. THE SFC RIDGE AXIS EXTENDING FROM THE WESTERN ATLANTIC HIGH IS PROGGED TO DROP SOUTH OF THE ILM WATERS PRIOR AS IT EXTENDS INLAND. THIS WILL RESULT IN A SW WIND DIRECTION BECOMING DOMINANT THROUGHOUT THE AREA WATERS DURING THIS TIME PERIOD. IN ADDITION...THE PIEDMONT TROF ACROSS THE CENTRAL CAROLINAS WILL BEGIN TO MATERIALIZE BY LATE IN THIS PERIOD. THE SFC PG WILL REMAIN SOMEWHAT ON THE LOOSE SIDE THIS...AND SHOULD SUPPORT 10 TO POSSIBLY 15 KT WIND SPEEDS. THE HIER SPEEDS WILL BE AIDED BY THE SEA BREEZE CIRCULATION NEAR SHORE. SIGNIFICANT SEAS WILL RUN AROUND 3 FEET...WITH FLUCTUATIONS BETWEEN 2 AND 4 FT. THE ESE-SE GROUND SWELL AT 7 TO 9 SECOND PERIODS WILL DOMINATE THE SIGNIFICANT SEAS. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 AM TUESDAY...BERMUDA HIGH PRESSURE REMAINS ANCHORED OFFSHORE THROUGH THE PERIOD CONTINUING SW WINDS ACROSS THE WATERS. WHILE THE PATTERN IS FAIRLY STATIC...GRADIENT WILL SLOWLY TIGHTEN...ESPECIALLY THURSDAY...THANKS TO A STRENGTHENING PIEDMONT TROUGH AND SLOWLY APPROACHING COLD FRONT. THIS CAUSES SW WINDS TO INCREASE FROM 10-15 KTS ON WEDNESDAY...TO 15-20 KTS DURING THURSDAY. WHILE A RESIDUAL 8 SEC SE SWELL WILL PERSIST IN THE WAVE SPECTRUM...SEAS WILL BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE INCREASING WINDS. SIGNIFICANT WAVE AMPLITUDES WILL GROW FROM 2-4 FT WEDNESDAY...TO 3-5 FT THURSDAY...AND A FEW 6 FTERS MAY DEVELOP BY THE END OF THE PERIOD...AND WILL NEED TO MONITOR THIS FOR A POTENTIAL SCA BEGINNING LATE THURSDAY NIGHT. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 300 AM TUESDAY...HIGH PRESSURE ANCHORED WELL OFFSHORE AND COLD FRONT STALLED WELL INLAND FROM THE COAST...WILL KEEP A CONTINUOUSLY TIGHTENING PRESSURE GRADIENT OVER THE WATERS. THIS HELPS SW WINDS RISE TO AROUND 20 KTS BOTH DAYS...AND SEAS BUILD IN RESPONSE TO THESE GUSTY WINDS. WAVE HEIGHTS WILL BE 4-7 FT THROUGH THE PERIOD...AND AN EXTENDED SMALL CRAFT ADVISORY IS POSSIBLE FOR ALL LOCAL WATERS. && .TIDES/COASTAL FLOODING... AS OF 615 AM TUESDAY...THE HIGH TIDE CYCLE LATE TONIGHT WILL AGAIN BREACH THE 5.5 FT MLLW SHALLOW COASTAL FLOOD THRESHOLD...AS MEASURED BY THE ILM TIDE GAGE ALONG THE CAPE FEAR RIVER OF DOWNTOWN WILMINGTON. THE WINDOW FOR THE COASTAL FLOOD THREAT WILL RUN BETWEEN MIDNIGHT AND 2 AM WEDNESDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...JDW LONG TERM...JDW AVIATION...DL TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
626 AM EDT TUE JUN 25 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE CENTERED WELL OFFSHORE WILL REMAIN IN PLACE INTO THE WEEKEND...WHILE WEAK UPPER IMPULSES TRACK JUST NORTH OF THE AREA. THIS WILL CONTINUE THE WARM AND HUMID CONDITIONS ACROSS THE AREA...WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 615 AM TUESDAY...MODELS INDICATE RATHER LOW AMPLITUDE IE. FLAT MID AND UPPER LEVEL RIDGING EXTENDING NW ACROSS THE AREA FROM THE BASE OR CENTER LOCATED OVER THE OFFSHORE WATERS OFF THE SE U.S. COAST. MODELS INDICATE WEAK MID-LEVEL TROFFINESS ACROSS THE SE STATES WHICH WILL LIKELY BE ENOUGH TO AID IN FIRING DIURNALLY DRIVEN CONVECTION. THE SEA BREEZE AND OUTFLOWS WILL BE THE OTHER AIDS TO KEEP CONVECTION FIRING THROUGHOUT THE DAY AND INTO THE EVENING. LATEST HRRR DOES INDICATE CONVECTION TO FIRE AROUND SUNRISE BUT NOT BOUGHT ON ITS WIDESPREAD COVERAGE THAT EARLY. THINKING IS SOMEWHAT SIMILAR TO MONDAY CONCERNING POPS IN THE 30-50 PERCENT RANGE BY MID MORNING AND LASTING THROUGH MID- EVENING. NAMBUFR SOUNDINGS INDICATE 1.75 TO 2.00 PRECIPITABLE WATERS ACROSS THE FA ONCE AGAIN. THEREFORE...THE MAIN THREAT FROM TODAYS CONVECTION WILL BE THE HEAVY DOWNPOURS ACROSS GROUNDS THAT HAVE BECOME SOMEWHAT SATURATED FROM THE RECENT RAINS OF THE PAST FEW DAYS. WILL ONCE AGAIN HAVE A LOW DIURNAL RANGE BETWEEN MAX AND MIN TEMPS DUE TO CLOUDS AND THE PCPN THREAT. STAYED ON THE LOWER SIDE OF MODEL MOS GUIDANCE FOR TODAYS MAXES...AND THE HIGHER SIDE OF MODEL MOS FOR TONIGHTS LOWS. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 AM TUESDAY...PERSISTENCE THE RULE FOR THE SHORT TERM AS SUMMERTIME PATTERN REMAINS IN PLACE WITH BERMUDA HIGH OFFSHORE AND FLAT RIDGING CONTINUING ALOFT. THIS CREATES A WARM...HUMID...AND ACTIVE PATTERN AS TEMPS RISE INTO THE LOW 90S AWAY FROM THE COAST...WITH LOWS FALLING ONLY INTO THE LOW 70S. HOWEVER...THERE WILL LIKELY BE CONSIDERABLE VARIABILITY EACH DAY AS CONVECTION LOOKS TO BE SCATTERED-TO-WIDESPREAD ACROSS THE AREA. IN ADDITION TO THE FLAT 5H RIDGING WHICH SLOWLY BEGINS TO BREAK DOWN...A WEAK VORT WILL CROSS OVERHEAD ON WEDNESDAY. TIMING THIS FEATURE IS STILL UNCERTAIN...AND THERE WILL BE A RACE BETWEEN SUBSIDENCE BEHIND THE VORT...AND AFTN INSTABILITY. ASSUMING THE VORT MOVES OFFSHORE EARLY...WILL CAP POP AT LOW-CHC...AND WEDNESDAY MAY BE THE DRIEST DAY OF THE WEEK. BY THURSDAY...MID LEVEL LAPSE RATES STEEPEN CONSIDERABLY AND MORE WIDESPREAD CONVECTION IS ANTICIPATED IN A CONTINUED HIGHLY UNSTABLE ENVIRONMENT. WHILE SEVERE CONVECTION LOOKS UNLIKELY...OR ISOLATED AT WORST...HEAVY RAIN AND FLOODING WILL CONTINUE TO BE A CONCERN IN A SATURATED COLUMN. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 300 AM TUESDAY...BIG CHANGES TO THE UPPER PATTERN DURING THE EXTENDED...BUT LITTLE SENSIBLE WEATHER DIFFERENCES TO BE EXPERIENCED ACROSS THE EASTERN CAROLINAS. 600DM RIDGE AT 5H EXPANDS ACROSS THE SW...CENTERED OVER THE 4-CORNERS REGION...FORCING A DEEPENING EASTERN CONUS TROUGH. LONGWAVE PATTERN BECOMES INCREASINGLY AMPLIFIED...WITH THE EASTERN TROUGH BOOKENDED BY LARGE RIDGES BOTH UPSTREAM AND DOWNSTREAM. THIS CAUSES THE LONGITUDINAL FLOW TO COME TO A SLOW/HALT...AND THE EASTERN TROUGH WILL PERSIST THROUGH THE EXTENDED. HOWEVER...WITH TROUGH AXIS REMAINING WELL WEST OF THE AREA...DEEP SW FLOW WILL ADVECT TREMENDOUS MOISTURE AGAIN INTO THE COLUMN...EVEN AS BERMUDA HIGH SLOWLY BREAKS DOWN. THIS SUPPORTS THE POTENTIAL FOR A VERY WET PERIOD RETURNING TO THE CAROLINAS...AND SAT-MON COULD BE EVEN WETTER THAN THE PAST FEW DAYS HAVE BEEN. WPC QPF GRAPHICS SUPPORT THIS...AS CHANNELED MOISTURE TAPS THE GULF OF MEXICO AND STREAMS RIGHT INTO THE AREA. FOR NOW WILL CONTINUE CHC POP THROUGH THE PERIOD WITH HIGHS RIGHT AROUND CLIMO AND LOWS JUST A BIT ABOVE. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... AS OF 06Z...FOG/LOW STRATUS WILL LIKELY PLAGUE THE TERMINALS AGAIN EARLY THIS MORNING WITH THIS HUMID AIR MASS REMAINING ACROSS THE REGION. POCKETS OF MVFR VSBYS ARE POSSIBLE...WITH MAINLY IFR CIGS INLAND...BELOW 1K FEET...AND MVFR CIGS ALONG THE COAST. CANNOT RULE OUT TEMPO IFR FOR THE COASTAL SITES...BUT CONFIDENCE IS HIGHER FOR IFR CIGS AT KLBT/KFLO. SHRA/TSRA LIKELY WILL DEVELOP NEAR THE COAST IN THE MORNING BEFORE SHRA/TSRA SHIFTS INLAND DURING THE AFTN...WITH THE SEA BREEZE AND OUTFLOW BOUNDARIES BEING THE PRIMARY LIFTING MECHANISMS. TEMPO MVFR/IFR WILL OCCUR IN HEAVY DOWNPOURS...BUT PREVAILING VFR IS EXPECTED DURING THE DAY. RIDGING ACROSS THE AREA FROM THE WESTERN ATLANTIC HIGH WILL PRODUCE S/SW WINDS AROUND 5 KTS INLAND TERMINALS...AROUND 10 KT...EXCEPT UP TO 15 KT ACROSS THE COASTAL TERMS DURING THE HEIGHT OF THE SEA BREEZE CIRCULATION LATER TODAY. EXTENDED OUTLOOK...ISO/SCT AFTERNOON SHOWERS AND T-STORMS THROUGH SATURDAY WITH LOCALIZED PERIODS OF MVFR/IFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 615 AM TUESDAY...WEAK RIDGING SFC AND ALOFT WILL CONTINUE ITS HOLD ACROSS THE AREA WATERS THIS NEAR TERM PERIOD. THE SFC RIDGE AXIS EXTENDING FROM THE WESTERN ATLANTIC HIGH IS PROGGED TO DROP SOUTH OF THE ILM WATERS PRIOR AS IT EXTENDS INLAND. THIS WILL RESULT IN A SW WIND DIRECTION BECOMING DOMINANT THROUGHOUT THE AREA WATERS DURING THIS TIME PERIOD. IN ADDITION...THE PIEDMONT TROF ACROSS THE CENTRAL CAROLINAS WILL BEGIN TO MATERIALIZE BY LATE IN THIS PERIOD. THE SFC PG WILL REMAIN SOMEWHAT ON THE LOOSE SIDE THIS...AND SHOULD SUPPORT 10 TO POSSIBLY 15 KT WIND SPEEDS. THE HIER SPEEDS WILL BE AIDED BY THE SEA BREEZE CIRCULATION NEAR SHORE. SIGNIFICANT SEAS WILL RUN AROUND 3 FEET...WITH FLUCTUATIONS BETWEEN 2 AND 4 FT. THE ESE-SE GROUND SWELL AT 7 TO 9 SECOND PERIODS WILL DOMINATE THE SIGNIFICANT SEAS. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 AM TUESDAY...BERMUDA HIGH PRESSURE REMAINS ANCHORED OFFSHORE THROUGH THE PERIOD CONTINUING SW WINDS ACROSS THE WATERS. WHILE THE PATTERN IS FAIRLY STATIC...GRADIENT WILL SLOWLY TIGHTEN...ESPECIALLY THURSDAY...THANKS TO A STRENGTHENING PIEDMONT TROUGH AND SLOWLY APPROACHING COLD FRONT. THIS CAUSES SW WINDS TO INCREASE FROM 10-15 KTS ON WEDNESDAY...TO 15-20 KTS DURING THURSDAY. WHILE A RESIDUAL 8 SEC SE SWELL WILL PERSIST IN THE WAVE SPECTRUM...SEAS WILL BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE INCREASING WINDS. SIGNIFICANT WAVE AMPLITUDES WILL GROW FROM 2-4 FT WEDNESDAY...TO 3-5 FT THURSDAY...AND A FEW 6 FTERS MAY DEVELOP BY THE END OF THE PERIOD...AND WILL NEED TO MONITOR THIS FOR A POTENTIAL SCA BEGINNING LATE THURSDAY NIGHT. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 300 AM TUESDAY...HIGH PRESSURE ANCHORED WELL OFFSHORE AND COLD FRONT STALLED WELL INLAND FROM THE COAST...WILL KEEP A CONTINUOUSLY TIGHTENING PRESSURE GRADIENT OVER THE WATERS. THIS HELPS SW WINDS RISE TO AROUND 20 KTS BOTH DAYS...AND SEAS BUILD IN RESPONSE TO THESE GUSTY WINDS. WAVE HEIGHTS WILL BE 4-7 FT THROUGH THE PERIOD...AND AN EXTENDED SMALL CRAFT ADVISORY IS POSSIBLE FOR ALL LOCAL WATERS. && .TIDES/COASTAL FLOODING... AS OF 615 AM TUESDAY...THE HIGH TIDE CYCLE LATE TONIGHT WILL AGAIN BREACH THE 5.5 FT MLLW SHALLOW COASTAL FLOOD THRESHOLD...AS MEASURED BY THE ILM TIDE GAGE ALONG THE CAPE FEAR RIVER OF DOWNTOWN WILMINGTON. THE WINDOW FOR THE COASTAL FLOOD THREAT WILL RUN BETWEEN MIDNIGHT AND 2 AM WEDNESDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...JDW LONG TERM...JDW AVIATION...DL TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
342 AM EDT TUE JUN 25 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE CENTERED WELL OFFSHORE WILL REMAIN IN PLACE INTO THE WEEKEND...WHILE WEAK UPPER IMPULSES TRACK JUST NORTH OF THE AREA. THIS WILL CONTINUE THE WARM AND HUMID CONDITIONS ACROSS THE AREA...WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM TUESDAY...WILL KEEP A SLIGHT POP ALONG THE IMMEDIATE COAST DURING THE PRE-DAWN HOURS TO ACCOUNT FOR ANY ONSHORE MOVEMENT OF ATLANTIC SHRA/TSRA. MODELS INDICATE RATHER FLAT UPPER RIDGING EXTENDING NW ACROSS THE AREA FROM THE OFFSHORE WATERS OFF THE SE U.S. COAST. MODELS INDICATE WEAK MID-LEVEL TROFFINESS ACROSS THE SE STATES WHICH WILL LIKELY BE ENOUGH TO AID IN FIRING DIURNALLY DRIVEN CONVECTION. THE SEA BREEZE AND OUTFLOWS WILL BE THE OTHER AIDS TO KEEP CONVECTION FIRING THROUGH THE DAY AND INTO THE EVENING. LATEST HRRR DOES INDICATE CONVECTION TO FIRE AROUND SUNRISE BUT NOT BOUGHT ON ITS WIDESPREAD COVERAGE THAT EARLY. THINKING IS SOMEWHAT SIMILAR TO MONDAY CONCERNING POPS IN THE 30-50 PERCENT RANGE BY MID MORNING AND LASTING THROUGH MID-EVENING. NAMBUFR SOUNDINGS INDICATE 1.75 TO 2.00 PRECIPITABLE WATERS ACROSS THE FA ONCE AGAIN. THEREFORE...THE MAIN THREAT FROM TODAYS CONVECTION WILL BE THE HEAVY DOWNPOURS ACROSS GROUNDS THAT HAVE BECOME SOMEWHAT SATURATED FROM THE RECENT RAINS OF THE PAST FEW DAYS. WILL ONCE AGAIN HAVE A LOW DIURNAL RANGE BETWEEN MAX AND MIN TEMPS DUE TO CLOUDS AND PCPN THREAT. STAYED ON THE LOWER SIDE OF MODEL MOS GUIDANCE FOR TODAYS MAXES...AND THE HIGHER SIDE OF MODEL MOS FOR TONIGHTS LOWS. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 AM TUESDAY...PERSISTENCE THE RULE FOR THE SHORT TERM AS SUMMERTIME PATTERN REMAINS IN PLACE WITH BERMUDA HIGH OFFSHORE AND FLAT RIDGING CONTINUING ALOFT. THIS CREATES A WARM...HUMID...AND ACTIVE PATTERN AS TEMPS RISE INTO THE LOW 90S AWAY FROM THE COAST...WITH LOWS FALLING ONLY INTO THE LOW 70S. HOWEVER...THERE WILL LIKELY BE CONSIDERABLE VARIABILITY EACH DAY AS CONVECTION LOOKS TO BE SCATTERED-TO-WIDESPREAD ACROSS THE AREA. IN ADDITION TO THE FLAT 5H RIDGING WHICH SLOWLY BEGINS TO BREAK DOWN...A WEAK VORT WILL CROSS OVERHEAD ON WEDNESDAY. TIMING THIS FEATURE IS STILL UNCERTAIN...AND THERE WILL BE A RACE BETWEEN SUBSIDENCE BEHIND THE VORT...AND AFTN INSTABILITY. ASSUMING THE VORT MOVES OFFSHORE EARLY...WILL CAP POP AT LOW-CHC...AND WEDNESDAY MAY BE THE DRIEST DAY OF THE WEEK. BY THURSDAY...MID LEVEL LAPSE RATES STEEPEN CONSIDERABLY AND MORE WIDESPREAD CONVECTION IS ANTICIPATED IN A CONTINUED HIGHLY UNSTABLE ENVIRONMENT. WHILE SEVERE CONVECTION LOOKS UNLIKELY...OR ISOLATED AT WORST...HEAVY RAIN AND FLOODING WILL CONTINUE TO BE A CONCERN IN A SATURATED COLUMN. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 300 AM TUESDAY...BIG CHANGES TO THE UPPER PATTERN DURING THE EXTENDED...BUT LITTLE SENSIBLE WEATHER DIFFERENCES TO BE EXPERIENCED ACROSS THE EASTERN CAROLINAS. 600DM RIDGE AT 5H EXPANDS ACROSS THE SW...CENTERED OVER THE 4-CORNERS REGION...FORCING A DEEPENING EASTERN CONUS TROUGH. LONGWAVE PATTERN BECOMES INCREASINGLY AMPLIFIED...WITH THE EASTERN TROUGH BOOKENDED BY LARGE RIDGES BOTH UPSTREAM AND DOWNSTREAM. THIS CAUSES THE LONGITUDINAL FLOW TO COME TO A SLOW/HALT...AND THE EASTERN TROUGH WILL PERSIST THROUGH THE EXTENDED. HOWEVER...WITH TROUGH AXIS REMAINING WELL WEST OF THE AREA...DEEP SW FLOW WILL ADVECT TREMENDOUS MOISTURE AGAIN INTO THE COLUMN...EVEN AS BERMUDA HIGH SLOWLY BREAKS DOWN. THIS SUPPORTS THE POTENTIAL FOR A VERY WET PERIOD RETURNING TO THE CAROLINAS...AND SAT-MON COULD BE EVEN WETTER THAN THE PAST FEW DAYS HAVE BEEN. WPC QPF GRAPHICS SUPPORT THIS...AS CHANNELED MOISTURE TAPS THE GULF OF MEXICO AND STREAMS RIGHT INTO THE AREA. FOR NOW WILL CONTINUE CHC POP THROUGH THE PERIOD WITH HIGHS RIGHT AROUND CLIMO AND LOWS JUST A BIT ABOVE. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... AS OF 06Z...FOG/LOW STRATUS WILL LIKELY PLAGUE THE TERMINALS AGAIN EARLY THIS MORNING WITH THIS HUMID AIR MASS REMAINING ACROSS THE REGION. POCKETS OF MVFR VSBYS ARE POSSIBLE...WITH MAINLY IFR CIGS INLAND...BELOW 1K FEET...AND MVFR CIGS ALONG THE COAST. CANNOT RULE OUT TEMPO IFR FOR THE COASTAL SITES...BUT CONFIDENCE IS HIGHER FOR IFR CIGS AT KLBT/KFLO. SHRA/TSRA LIKELY WILL DEVELOP NEAR THE COAST IN THE MORNING BEFORE SHRA/TSRA SHIFTS INLAND DURING THE AFTN...WITH THE SEA BREEZE AND OUTFLOW BOUNDARIES BEING THE PRIMARY LIFTING MECHANISMS. TEMPO MVFR/IFR WILL OCCUR IN HEAVY DOWNPOURS...BUT PREVAILING VFR IS EXPECTED DURING THE DAY. RIDGING ACROSS THE AREA FROM THE WESTERN ATLANTIC HIGH WILL PRODUCE S/SW WINDS AROUND 5 KTS INLAND TERMINALS...AROUND 10 KT...EXCEPT UP TO 15 KT ACROSS THE COASTAL TERMS DURING THE HEIGHT OF THE SEA BREEZE CIRCULATION LATER TODAY. EXTENDED OUTLOOK...ISO/SCT AFTERNOON SHOWERS AND T-STORMS THROUGH SATURDAY WITH LOCALIZED PERIODS OF MVFR/IFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM TUESDAY...RIDGING SFC AND ALOFT WILL CONTINUE ITS HOLD ACROSS THE AREA WATERS THIS NEAR TERM PERIOD. THE SFC RIDGE AXIS EXTENDING FROM THE WESTERN ATLANTIC HIGH IS PROGGED TO DROP SOUTH OF THE ILM WATERS PRIOR TO EXTENDING INLAND. THIS WILL RESULT IN A SW WIND DIRECTION BECOMING DOMINANT THROUGHOUT THE AREA WATERS DURING THIS TIME PERIOD. IN ADDITION...THE PIEDMONT TROF ACROSS THE CENTRAL CAROLINAS WILL BEGIN TO MATERIALIZE BY LATE IN THE PERIOD. THE SFC PG WILL REMAIN SOMEWHAT ON THE LOOSE SIDE THIS PERIOD...AND SHOULD SUPPORT 10 TO POSSIBLY 15 KT WIND SPEEDS. THE HIER SPEEDS LIKELY TO BE AIDED BY THE SEA BREEZE CIRCULATION NEAR SHORE. SIGNIFICANT SEAS WILL RUN AROUND 3 FEET...WITH FLUCTUATIONS BETWEEN 2 AND 4 FT. THE ESE-SE GROUND SWELL AT 7 TO 9 SECOND PERIODS WILL DOMINATE THE SIGNIFICANT SEAS. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 AM TUESDAY...BERMUDA HIGH PRESSURE REMAINS ANCHORED OFFSHORE THROUGH THE PERIOD CONTINUING SW WINDS ACROSS THE WATERS. WHILE THE PATTERN IS FAIRLY STATIC...GRADIENT WILL SLOWLY TIGHTEN...ESPECIALLY THURSDAY...THANKS TO A STRENGTHENING PIEDMONT TROUGH AND SLOWLY APPROACHING COLD FRONT. THIS CAUSES SW WINDS TO INCREASE FROM 10-15 KTS ON WEDNESDAY...TO 15-20 KTS DURING THURSDAY. WHILE A RESIDUAL 8 SEC SE SWELL WILL PERSIST IN THE WAVE SPECTRUM...SEAS WILL BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE INCREASING WINDS. SIGNIFICANT WAVE AMPLITUDES WILL GROW FROM 2-4 FT WEDNESDAY...TO 3-5 FT THURSDAY...AND A FEW 6 FTERS MAY DEVELOP BY THE END OF THE PERIOD...AND WILL NEED TO MONITOR THIS FOR A POTENTIAL SCA BEGINNING LATE THURSDAY NIGHT. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 300 AM TUESDAY...HIGH PRESSURE ANCHORED WELL OFFSHORE AND COLD FRONT STALLED WELL INLAND FROM THE COAST...WILL KEEP A CONTINUOUSLY TIGHTENING PRESSURE GRADIENT OVER THE WATERS. THIS HELPS SW WINDS RISE TO AROUND 20 KTS BOTH DAYS...AND SEAS BUILD IN RESPONSE TO THESE GUSTY WINDS. WAVE HEIGHTS WILL BE 4-7 FT THROUGH THE PERIOD...AND AN EXTENDED SMALL CRAFT ADVISORY IS POSSIBLE FOR ALL LOCAL WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...JDW LONG TERM...JDW AVIATION...DCH/BJR MARINE...DCH/JDW
AREA FORECAST DISCUSSION
NWS BISMARCK ND
158 PM CDT TUE JUN 25 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 200 PM CDT TUE JUN 25 2013 FORECAST HIGHLIGHTS IN THE SHORT TERM FORECAST PERIOD WILL BE STRONG TO SEVERE THUNDERSTORMS AND HEAVY RAIN POTENTIAL THROUGH THIS EVENING. CURRENTLY...WARM AND VERY HUMID DAY WITH DAYTIME HIGHS IN THE 80S AND SURFACE DEWPOINT TEMPS FROM 60 TO THE LOW 70S. LATEST RADAR IS VOID OF ECHOS OVER WEST AND CENTRAL NORTH DAKOTA AS OF 2 PM CDT. LATEST MODEL GUIDANCE SUGGESTS CONVECTIVE DEVELOPMENT NORTHWEST/NORTH CENTRAL EARLY THIS AFTERNOON...BUILDING SOUTH- SOUTHEAST LATE AFTERNOON-EARLY EVENING ALONG A SURFACE TROUGH IN PLACE FROM NORTHWEST NORTH DAKOTA THROUGH CENTRAL SOUTH DAKOTA. 17-18Z RAP SOUNDINGS WEAKEN/ERASE THE CAP BETWEEN 20-22Z ALONG THE SFC TROUGH AXIS. TRIGGER WILL BE A STRONG MID LEVEL S/WV PUSHING INTO WESTERN NORTH DAKOTA NOW...HELPING TO WEAKEN THE STRONG CAPPING INVERSION CURRENTLY IN PLACE. CONVECTION SHOULD THEN PUSH EAST THIS EVENING INTO THE OVERNIGHT WITH THE MID LEVEL WAVE AND SFC TROUGH. STRONG TO SEVERE WEATHER REMAINS IN PLAY WITH THE VERY STRONG INSTABILITY PRESENT...CURRENTLY 3-6K J/KG. LIMITING FACTOR WILL BE RATHER WEAK 0-6KM/EFFECTIVE SHEAR UP TO AROUND 20KTS CURRENTLY IN PLACE AND FORECAST THROUGH THIS EVENING. STILL...WITH THE AMOUNT OF CAPE PRESENT THERE IS A GOOD PROBABILITY OF LARGE SEVERE HAIL AND A DAMAGING WIND GUSTS. STORMS WILL BE WATER LOADED SO WILL LIKELY NEED A RATHER ROBUST/TALL UPDRAFT TO GET THE LARGE HAIL. IT DOES APPEAR THE MAIN THREAT TODAY INTO THIS EVENING WILL BE VERY HEAVY RAINFALL ELEVATING THE THREAT FOR FLASH FLOODING. CONVECTIVE CHANCES WILL END FROM WEST TO EAST THIS EVENING THROUGH WEDNESDAY MORNING AS FORCING PUSHES EASTWARD. OPTED TO KEEP WEDNESDAY AFTERNOON DRY FOR NOW ALONG WITH THE 12Z GFS/00Z ECMWF. THE 06Z AND 12Z NAM BOTH PAINTED LIGHT DIURNALLY DRIVEN QPF...SO WILL LET LATER SHIFTS TAKE A LOOK WITH ATTENTION FOCUSED ON THE NEXT 12 HOURS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 200 PM CDT TUE JUN 25 2013 THE MAIN FEATURE FOR THE EXTENDED PERIOD WILL BE THE INTENSIFYING UPPER LEVEL RIDGE OVER THE WESTERN US/CANADA AS FORECAST BY THE 12Z MODEL SUITE. WITH THE RIDGE AXIS POSITIONED OVER THE INTERMOUNTAIN WEST...NORTH TO NORTHWESTERLY FLOW WILL BE DOMINANT ACROSS NORTH DAKOTA FOR MUCH OF THE PERIOD. THIS WILL ALLOW FOR SEASONABLE TEMPERATURES...IN THE 80S TO CONTINUE...KEEPING THE AREA OUT THE WARMEST H850 TEMPERATURES THAT WILL DEVELOP ACROSS THE WESTERN US. OVERALL THE FORECAST WILL REMAIN DRY...HOWEVER THERE WILL BE PERIODIC CHANCES FOR PRECIPITATION FOR PARTS OF CENTRAL AND EASTERN NORTH DAKOTA...AS A FEW SHORTWAVES ROTATE AROUND THE WESTERN PERIPHERY OF THE UPPER LEVEL LOW POSITIONED OVER THE GREAT LAKES REGION. LATE THIS WEEKEND/EARLY NEXT WEEK...SOME UNCERTAINTY IS INTRODUCED INTO THE FORECAST AS THE THERE IS SOME DISAGREEMENT AMONGST THE 12Z LONG RANGE MODELS REGARDING THE POTENT SHORTWAVE THAT IS PROGGED TO DROP SOUTH FROM CANADA AND INTO THE NORTHERN PLAINS. DUE TO THIS UNCERTAINTY...WILL MAKE NO CHANGES TO THE ALLBLEND SOLUTION AT THIS TIME SINCE THERE IS NO TARGET OF OPPORTUNITY TO IMPROVE FORECAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 200 PM CDT TUE JUN 25 2013 AREAS OF MVFR CU/STRATUS ACROSS WEST AND CENTRAL ND. OTHERWISE...THUNDERSTORMS ARE EXPECTED FOR MUCH OF NORTHERN AND CENTRAL NORTH DAKOTA THIS AFTERNOON AND EVENING. SOME STORMS MAY BE STRONG TO SEVERE. HAVE ADDED A TEMPO GROUP OF +TSRA FOR KMOT FROM 21-24 UTC GIVEN GOOD CONFIDENCE OF THUNDERSTORMS WITH HEAVY RAINFALL TO IMPACT THE TERMINAL. WILL UPDATE OTHER TERMINAL FORECASTS AS NEEDED. && .HYDROLOGY... ISSUED AT 200 PM CDT TUE JUN 25 2013 A FLASH FLOOD WATCH REMAINS IN EFFECT FOR NORTHWEST AND CENTRAL NORTH DAKOTA THROUGH THIS EVENING. VERY SLOW MOVING THUNDERSTORMS WITH INTENSE RAINFALL RATES ARE EXPECTED. ONE HOUR FLASH FLOOD GUIDANCE IS AROUND ONE TO ONE AND A HALF INCHES ACROSS MOST OF THE WATCH AREA. RAINFALL RATES WITH THUNDERSTORMS TODAY WILL EASILY SURPASS THIS THRESHOLD...AND WILL HAVE TO CLOSELY MONITOR FOR FLASH FLOODING THIS AFTERNOON AND EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR NDZ001-002-009-010-017>020-034-042-045. FLASH FLOOD WATCH UNTIL 1 AM CDT WEDNESDAY FOR NDZ003>005- 011>013-021>023-025-035>037-046>048-050-051. && $$ SHORT TERM/HYDROLOGY...NH LONG TERM...LTH AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
101 PM CDT TUE JUN 25 2013 .UPDATE... ISSUED AT 100 PM CDT TUE JUN 25 2013 LOW LEVEL CLOUDS REMAIN ACROSS THE SOUTHERN RED RIVER VALLEY AND ARE TRYING TO ADVECT NORTHWARD. STILL THINKING THAT THESE SHOULD SCATTER AND WILL STICK WITH FORECASTED MAX TEMPS. DID INCREASE SKY COVER THROUGH THE AFTERNOON. SEVERE THREAT...WEAK DEEP LAYER SHEAR WILL LIKELY LEAD TO A LIMITED SEVERE THREAT. MODERATE INSTABILITY IN PLACE ACROSS THE WESTERN FA SHOULD LEAD TO A COUPLE SEVERE STORMS EARLY THIS EVENING. HRRR AND 4KM-WRF MODELS INDICATING THAT A SEVERE THUNDERSTORM WIND THREAT MAY PERSIST UNTIL MIDNIGHT FOR EASTERN NORTH DAKOTA. HEAVY RAIN THREAT...VERY SLOW STORM MOTION COMBINED WITH PWATS AOA 1.5 INCHES WILL LEAD TO AN INCREASED HEAVY RAIN THREAT. HOWEVER...COVERAGE OF THE STORMS SHOULD DECREASE AS THE STORMS MOVE THROUGH EASTERN NORTH DAKOTA (CONSIDERING TIMING WILL BE NEAR AND AFTER SUNSET). INCOMING HI-RES MODELS DEVELOP SLOW MOVING STORMS ACROSS WEST CENTRAL NORTH DAKOTA...WITH THE THUNDERSTORM AREA BECOMING MORE PROGRESSIVE AS IT BECOMES MORE OF A SEVERE WIND THREAT. WILL CONTINUE TO MONITOR...BUT EXPECTED AREAL COVERAGE OF HEAVY RAIN NOT ENOUGH FOR A FLASH FLOOD WATCH. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 330 AM CDT TUE JUN 25 2013 THE MAIN CHALLENGE WILL BE SHOWERS AND THUNDERSTORM POTENTIAL LATER THIS AFTERNOON INTO WED. MODELS ARE IN DECENT AGREEMENT OVERALL...AND PREFER THE SLIGHTLY SLOWER GFS/WRF FOR THE EVOLUTION OF CONVECTION LATER THIS AFTERNOON AND TONIGHT. FOR TODAY...THE MORNING SHOULD REMAIN DRY FOR ALL AREAS AS A SHORTWAVE AND SFC BOUNDARY MOVE INTO CENTRAL ND. THERE SHOULD BE SHOWERS AND STORMS DEVELOPING IN OUR WESTERN AREAS LATE IN THE DAY...WITH MOST AREAS REMAINING DRY AND WARM THROUGH 00Z WED. FOR TONIGHT...EXPECT SHOWERS AND STORMS TO MOVE SLOWLY FROM WEST TO EAST. PRECIPITABLE WATERS INCREASE TO OVER 1.5 INCHES IN ALL AREAS AROUND 06Z...WITH A SHORTWAVE TROUGH AND WEAK SFC BOUNDARY. THERE IS NOT A STRONG OR FOCUSED LOW LEVEL JET THOUGH...SO THIS COULD PRECLUDE A MORE ORGANIZED MCS FROM FORMING. IN ADDITION...DEEP LAYERED SHEAR VALUES ARE WEAK...ONLY AROUND 15KT. INSTABILITY WILL BE FAIRLY HIGH AT LEAST THIS EVENING IN THE WEST WITH MLCAPE AROUND 2000 J/KG. THE CURRENT THINKING IS A BROKEN LINE OF STORMS WILL AFFECT THE WESTERN AREAS BY EVENING...THEN MOVE INTO THE VALLEY AROUND 06Z THEN INTO THE EAST THEREAFTER. THE MAIN THREAT SHOULD BE LOCALLY HEAVY RAINFALL GIVEN THE HIGH PWATS AND SLOW MOVEMENT OF STORMS WITH WEAK WINDS ALOFT. CAN/T RULE OUT A SEVERE STORM OR TWO...MAINLY IN THE WEST THIS EVENING...WITH HAIL AND WIND THE MAIN THREATS. THERE COULD BE SOME LOCALIZED FLOODING ISSUES WHERE STORMS DEVELOP...SO THIS WILL HAVE TO BE MONITORED. FOR NOW WON/T ISSUE A FLASH FLOOD WATCH...BUT THIS IS SOMETHING TO CONSIDER AS WE HEAD THROUGH TODAY. WE WILL MENTION HEAVY RAIN IN THE GRIDS/HWO IN ALL AREAS TONIGHT. ON WEDNESDAY...THE BEST CHANCE FOR SHOWERS AND STORMS SHOULD MOVE INTO OUR MN COUNTIES. THE LATEST MODEL TRENDS ARE FOR A SLOWER MOVEMENT TO THE EAST THOUGH...SO THERE COULD BE SOME CONVECTION ALONG AND EAST OF THE VALLEY THROUGH AT LEAST EARLY AFTERNOON WITH INSTABILITY REMAINING. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 330 AM CDT TUE JUN 25 2013 FOR WED NIGHT...EXPECT THE THREAT FOR SHOWERS AND STORMS EARLY IN THE NORTHEAST BEFORE DRIER AIR MOVES IN AFTER 06Z THU. ON THURSDAY...THE MORNING SHOULD BE DRY WITH INCREASING NW WINDS BY AFTERNOON. IT SHOULD BECOME BREEZY TO PERHAPS WINDY IN MOST AREAS WITH ABOUT 30KT TO MIX AND ADIABATIC SOUNDINGS TO 750MB. BY AFTERNOON...SOME WEAK INSTABILITY IS POSSIBLE IN THE NORTHEAST WITH SOME LINGERING CYCLONIC FLOW...SO WILL MENTION A LOW CHANCE FOR SOME SHOWERS AND STORMS HERE. TEMPS SHOULD WARM ABOVE NORMAL WITH MILD MID LEVEL TEMPS. FOR FRIDAY THROUGH MONDAY NIGHT...A LONGWAVE SYNOPTIC PATTERN WILL REMAIN. EXPECT A FAIRLY STABLE FRIDAY THROUGH NEXT WEEKEND WITH THE GFS/ECMWF/GEM/DGEX ALL SHOWING A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS AND A DEEP TROUGH PARKED OVER THE OHIO RIVER VALLEY. AS A RESULT...THE NORTHERN PLAINS WILL BE UNDER THE INFLUENCE OF NORTHWEST FLOW ALOFT. TIMING AND PLACEMENT OF WEAK SHORT-WAVES IN THIS FLOW IS DIFFICULT...SO WILL FOLLOW ALL BLEND 20 POPS FOR MOST PERIODS. TEMPERATURES WILL BE NEAR SEASONAL NORMALS WITH HIGHS IN THE UPPER 70S TO LOWER 80S AND LOWS IN THE UPPER 50S TO LOWER 60S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 100 PM CDT TUE JUN 25 2013 AREA OF MVFR CIGS WILL PERSIST ACROSS SERN ND INTO WCNTRL MN THROUGH EARLY AFTERNOON...BECOMING SCATTERED TO BKN IN THE MID AFTERNOON. AREAS OF SHOWERS AND EMBEDDED TSTMS WITH MVFR CIGS AND VSBYS WILL DEVELOP THROUGH WESTERN AND CENTRAL ND IN THE LATE AFTERNOON. THESE WILL MOVE INTO EASTERN ND THROUGH THE EARLY EVENING...AND CROSS THE RRV INTIO NWRN MN IN THE LATE EVENING. && .HYDROLOGY... ISSUED AT 100 PM CDT TUE JUN 25 2013 THE RED RIVER AT WAHPETON HAS CRESTED AND THE RIVER LEVEL HAS RECEDED BACK TO MINOR FLOOD STAGE. THE SHEYENNE AT HARWOOD WILL EASE BELOW FLOOD STAGE THIS AFTERNOON. OTHERWISE...MINOR FLOODING CONTINUES AT FARGO...SABIN... DILWORTH AND WEST FARGO. SOME LOCALIZED HEAVY RAINFALL IS POSSIBLE TONIGHT...WHICH COULD IMPACT RIVER STAGES IF IT FALLS OVER ALREADY SWOLLEN RIVERS IN THE SOUTHERN RED RIVER VALLEY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...DK LONG TERM...DK/ROGERS AVIATION...GUST HYDROLOGY...WJB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
102 AM CDT TUE JUN 25 2013 .UPDATE... ISSUED AT 101 AM CDT TUE JUN 25 2013 DID INCREASE POPS ACROSS THE FAR NORTHWEST TO LIKELY NEAR 12 UTC GIVEN THE LATEST RADAR TRENDS OF THE ONGOING CONVECTION ACROSS EASTERN MONTANA. DO NOT ANTICIPATE THESE STORMS TO BE SEVERE GIVEN MARGINAL EFFECTIVE DEEP LAYER SHEAR OF 20-25 KTS AND A EXPECTED DECREASE IN HAIL AND DOWNDRAFT CAPE VALUES THROUGH THE NIGHT. OTHERWISE...THE REMAINDER OF THE FORECAST FOR TONIGHT IS ON TRACK. IN REGARDS TO TUESDAY...CONSIDERING THE NEED FOR A FLASH FLOOD WATCH FOR NORTHERN AND CENTRAL NORTH DAKOTA. VERY SLOW STORM MOTIONS ARE ANTICIPATED WITH PWAT VALUES CLIMBING TO 1.75 INCHES AND K INDEX VALUES OF 40 TO 45 C. UPDATE ISSUED AT 1000 PM CDT MON JUN 24 2013 CURRENTLY...AN LONE CELL WAS LOCATED OVER NORTHERN MCLEAN COUNTY IN CENTRAL NORTH DAKOTA. LATEST 01Z HRRR CONTINUES TO TRY AND DEVELOP CONVECTION ACROSS THE WEST AND NORTH CENTRAL OVERNIGHT SO CANT COMPLETELY RULE OUT A THUNDERSTORM. THEREFORE WILL CONTINUE TO CARRY A SLIGHT CHANCE OF STORMS TONIGHT. AFTER MIDNIGHT...THERE APPEARS TO BE A BETTER CHANCE OF CONVECTION OVER NORTHWEST NORTH DAKOTA AS CURRENT CONVECTION IN CENTRAL MONTANA TRANSLATES EAST. BULK SHEAR OVER THIS AREA SHOULD INCREASE OVERNIGHT AS A SHORTWAVE OVER THE NORTHWEST U.S. PUSHES INTO THE NORTHERN ROCKIES. THUS HAVE KEPT SOME HIGHER CHANCE POPS OVER THE NORTHWEST INTO THE FAR NORTH CENTRAL TOWARD MORNING. FOG CHANCES APPEAR MINIMAL WITH A STEADY SOUTHEAST FLOW...BUT DO THINK THERE IS A CHANCE OF INCREASING LOW STRATUS TUESDAY MORNING. NO CHANGES TO OVERNIGHT LOWS AS A WARM AND MUGGY NIGHT LOOKS TO BE IN STORE WITH LOWS IN THE LOW TO MID 60S. UPDATE ISSUED AT 709 PM CDT MON JUN 24 2013 UPDATE THIS EVENING DEALS MAINLY WITH EVENING CONVECTION. STILL QUITE UNSTABLE THIS EVENING BUT MODELS SUGGEST WITHOUT SUFFICIENTLY STRONG SHORTWAVE TO INITIATE CONVECTION...THE CAP WILL HOLD. THIS IS EVIDENT WITH THE CONVECTION THAT DEVELOPED JUST NORTH OF BISMARCK LATE THIS AFTERNOON...WHICH CONTINUES TO STRUGGLE TO SURVIVE. HAVE LOWERED POPS TO SLIGHT CHANCE ACROSS MOST OF THE AREA THIS EVENING. KEPT SOME CHANCE POPS IN THE FAR SOUTH IN CASE CONVECTION OVER WESTERN SOUTH DAKOTA MAKES IT UP TO THE BORDER. IF WE COULD GET A CELL TO BREAK THE CAP WE COULD STILL SEE A MARGINALLY SEVERE THUNDERSTORM BUT WITH A WEAK SHEAR PROFILE THIS EVENING...ORGANIZED CONVECTION LOOKS LESS LIKELY THAN IT DID EARLIER IN THE DAY. MODELS ALSO SUGGEST A CONTINUED INFLUX OF LOW LEVEL MOISTURE OVERNIGHT AND DEVELOP LOW STRATUS AFTER MIDNIGHT. THEREFORE BUMPED UP CLOUD COVER LATE TONIGHT...BUT WITH A STEADY SOUTHEAST GRADIENT...THINK THE POTENTIAL FOR FOG DEVELOPMENT IS LIMITED. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 300 PM CDT MON JUN 24 2013 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE STRONG TO SEVERE STORMS NOW THROUGH TUESDAY. LATEST HRRR...RAP...AND BOTH THE 12Z GFS/NAM ARE INDICATING CONVECTION FIRING OFF ANYWHERE FROM NOW THROUGH 21Z OVER THE SOUTHWEST AND SOUTH CENTRAL...SO WILL MAINTAIN HIGHER POPS FOR THESE AREAS. LOTS OF UNCERTAINTY YET WITH THE MID LEVEL CAPPING INVERSION STILL IN PLACE. WIND DISCONTINUITY/WEAK FRONTAL BOUNDARY IS APPARENT WHEN LOOKING AT WIND AND DEWPOINT FIELDS. MOISTURE IS CONVERGING ACROSS THE SOUTHWEST/SOUTH CENTRAL SOUTH OF THIS BOUNDARY WHERE SOUTHEAST WINDS ARE STRONGER. DEWPOINT TEMPS LOWER FARTHER NORTH WITH WEAKER SFC WINDS TO THE NORTH OF THIS BOUNDARY. INCOMING S/WV IMPULSE OVER NORTHWEST SOUTH DAKOTA NEARING SOUTHWEST NORTH DAKOTA WILL BE THE TRIGGER FOR POSSIBLE CONVECTION ONCE AFTERNOON HEATING CONTINUES TO WEAKEN THE CAP. STORMS WILL CONTINUE INTO THE EVENING BEFORE EVENTUALLY WINDING DOWN LATER THIS EVENING AND OVERNIGHT. STRONGER SHORT WAVE MOVES INTO THE DAKOTAS TUESDAY ALONG WITH A COLD FRONTAL PASSAGE TUESDAY AFTERNOON INTO TUESDAY EVENING. STRONG TO SEVERE CONVECTION WILL BE VERY POSSIBLE MANY AREAS...SO WILL MAINTAIN HIGH CHANCES FOR THUNDERSTORMS AND MENTION SEVERE. WILL NEED TO MONITOR LATEST GUIDANCE THIS EVENING AND TONIGHT IN CASE A FLASH FLOOD WATCH BECOMES NECESSARY. RIGHT NOW IT APPEARS STORMS WILL BE FAIRLY PROGRESSIVE. MODELS ARE ALSO PUTTING THE HEAVIEST QPF NORTHWEST AND NORTH CENTRAL...AWAY FROM THE AREAS WHICH RECEIVED THE HEAVIEST RAINFALL THE PAST SEVERAL DAYS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 300 PM CDT MON JUN 24 2013 SHORTWAVE TROUGH AND SURFACE COLD FRONT WILL BE EXITING THE JAMES RIVER VALLEY BY AROUND 06Z WEDNESDAY. EXPECT THREAT OF SEVERE WEATHER TO CONTINUE THROUGH TUESDAY EVENING THEN WANE WEST TO EAST AND END QUICKLY SHORTLY AFTER MIDNIGHT. BEHIND THE DEPARTING WAVE WEDNESDAY A WESTERLY FLOW ENSUES WITH ADDITIONAL SHORTWAVE ENERGY RIDING ACROSS SOUTHERN CANADA. TRENDS WITH THE 12Z RUNS PUSH PREVIOUS CHANCES OF PRECIPITATION FROM NORTH CENTRAL NORTH DAKOTA NOW INTO CANADA RESULTING IN AN OVERALL DRY SCENARIO. HAVE ADJUSTED THE GRIDS TO REFLECT THIS. THEREAFTER...MOSTLY A DRY WEATHER PATTERN AS A FOUR CORNERS HIGH PRESSURE AMPLIFIES NORTH WITH THE RIDGE AXIS EXTENDING WELL INTO SOUTHERN CANADA. HOWEVER A COMPENSATORY NORTHWEST FLOW DOWNSTREAM INTO NORTH DAKOTA WILL DOMINATE THROUGH THE WEEKEND WITH STILL SOME UNCERTAINTY ON HOW MANY SHORTWAVES WILL TOP THE RIDGE AND SLIDE THROUGH NORTHERN AND CENTRAL NORTH DAKOTA. THIS COULD PRODUCE SOME CONVECTION OVER THE WEEKEND...AND ESPECIALLY AT NIGHT WHICH IS A COMMON THEME WITH RIDGE RUNNERS TOPPING THE RIDGE THIS TIME OF YEAR. FAVORED AREAS WOULD BE THE TURTLE MOUNTAINS AND EAST CENTRAL NORTH DAKOTA. MODELS SHOWS A COUPLE OF WAVES EMBEDDED IN THE NORTHWEST FLOW...WITH THE ECMWF SHOWING THESE WAVES FURTHER EAST THAN THE GFS...SO TOO UNCLEAR ON EXACT DETAILS AT THIS TIME. WILL USE THE ALLBLEND WHICH CARRIES A SLIGHT MENTION OVER THE WEEKEND AND WILL NOT MAKE ANY CHANGES AT THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 101 AM CDT TUE JUN 25 2013 FOR TONIGHT...MVFR STRATUS AND FOG ARE POSSIBLE AT ALL TAF SITES...SUPPORTED BY THE LATEST LAMP GUIDANCE. THUNDERSTORMS ARE POSSIBLE AT KISN BY 12 UTC AS STORMS APPROACH FROM MONTANA. THUNDERSTORMS ARE EXPECTED FOR MUCH OF NORTHERN AND CENTRAL NORTH DAKOTA TUESDAY AFTERNOON AND EVENING. SOME STORMS MAY BE SEVERE. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...NH LONG TERM...KS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
152 PM EDT TUE JUN 25 2013 .SYNOPSIS... DISTURBANCES EMBEDDED IN WESTERLY FLOW ALOFT WILL INTERACT WITH A WARM AND UNSTABLE AIRMASS TO PROVIDE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE OHIO VALLEY THROUGH MID WEEK. THE GREATEST PRECIPITATION CHANCES WILL BE ON WEDNESDAY NIGHT...AS A COLD FRONT APPROACHES THE REGION. SLIGHTLY DRIER AND SLIGHTLY COOLER CONDITIONS ARE EXPECTED BY THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SATELLITE IMAGERY INDICATES CUMULUS DEVELOPING ACROSS MOST OF THE FORECAST AREA. THIS FIELD LOOKS A LITTLE MORE ROBUST IN CENTRAL OHIO SOUTH OF AN OLD OUTFLOW BOUNDARY. SO IT APPEARS THAT COULD BE THE AREA WHERE INITIAL STORMS DEVELOP OVER THE NEXT FEW HOURS. HRRR AND RAP HAVE BEEN SUGGESTING THAT ISOLATED TO SCATTERED CELLS WILL DEVELOP ALONG A NORTHEAST TO SOUTHWEST LINE...ROUGHLY NEAR THE I-71 CORRIDOR...BY MID AFTERNOON AND THEN MOVE OFF TO THE EAST BY LATE AFTERNOON. THERE WILL BE ENOUGH INSTABILITY TO ALLOW FOR SOME STRONGER STORMS. GIVEN TEMPERATURE TRENDS HAVE BUMPED UP HIGHS SLIGHTLY IN MOST PLACES. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... THE PRIMARY FOCUS FOR THE SHORT TERM WILL BE ON CONVECTION AHEAD OF A SHORTWAVE AND COLD FRONT ON WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. WEAK RIDGING OVER THE ILN CWA TONIGHT WILL BE UNLIKELY TO FAVOR NOCTURNAL CONVECTIVE DEVELOPMENT...WITH LLJ FORCING SETTING UP TO THE WEST. THOUGH A FEW CONVECTIVE ALLOWING MODELS DO SHOW UPSTREAM CONVECTION COMING INTO THE CWA (WHICH DOES SEEM REASONABLE GIVEN LINGERING INSTABILITY)...POPS WILL BE KEPT SOMEWHAT LOW DURING THE DIURNAL MIN (30 NW / 20 SE). ON WEDNESDAY...SOUTHWESTERLY FLOW OVER THE ILN CWA WILL INCREASE...AS MOISTURE TRANSPORT BEGINS TO RAMP UP JUST WEST OF THE CWA. A SHORTWAVE AND ASSOCIATED SURFACE LOW WILL BE MOVING ACROSS THE SOUTHERN GREAT LAKES. THE FORCING AHEAD OF THE SHORTWAVE SEEMS TO BE A BIT AHEAD OF THE ILL-DEFINED COLD FRONT TRAILING THE SURFACE LOW (WHICH WILL NOT LIKELY CROSS THE CWA UNTIL THURSDAY MORNING). THE OVERALL MODEL TREND SEEMS TO ALLOW FOR A SLIGHTLY QUICKER PASSAGE OF THE SHORTWAVE (WEDNESDAY AFTERNOON INTO WEDNESDAY OVERNIGHT) THAN IN PREVIOUS FORECASTS. WITH THIS FORECAST INCORPORATING THE PRESENCE (FINALLY) OF SOME WELL-DEFINED FORCING...AND EXPECTED UNSTABLE CONDITIONS (1500-2000 J/KG...PERHAPS UP TO 3000 J/KG IF UNINHIBITED BY CLOUDS OR PRECIPITATION DURING THE DAY)...LIKELY POPS HAVE BEEN INCLUDED FOR THE ENTIRE CWA. OF GREATER CONCERN IS THE INCREASING DYNAMICS WITH THE SYSTEM...AS WNW FLOW ALOFT COMBINES WITH A STRENGTHENING BAND OF LOW-LEVEL SOUTHWESTERLY FLOW TO CREATE A SHEARED ENVIRONMENT FAVORABLE FOR STORM ORGANIZATION. TOUGH TO RULE OUT ANY PARTICULAR TYPES OR MODES OF SEVERE WEATHER AT THIS POINT...AS THERE DOES APPEAR TO BE POTENTIAL FOR QUITE A BIT MORE THAN JUST THE RUN-OF-THE-MILL STRONG TO MARGINALLY SEVERE CONVECTION OF THE PAST FEW DAYS. THE HWO WORDING WILL BE REFINED A BIT FOR THIS THREAT...WHICH MAY CONTINUE INTO THE OVERNIGHT HOURS WEDNESDAY NIGHT. SEEING SOME HYDRO PARAMETERS LIGHT UP A BIT AS WELL (PWAT WELL OVER 1.50" AND GOOD MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE). THOUGH STORM ELEMENTS SHOULD BE SOMEWHAT PROGRESSIVE...SOME HEAVY RAIN WILL BE POSSIBLE. ANOTHER SHORTWAVE WILL IMPACT THE ILN CWA THURSDAY...THOUGH THE FORCING AHEAD OF THE MEAN TROUGH WILL GENERALLY BE EAST OF THE CWA. COOLING TEMPS ALOFT WILL HELP PROVIDE SOME INSTABILITY...SO CONVECTIVE CHANCES AGAIN EXIST THURSDAY (HIGHEST IN THE EASTERN CWA). IN THE WNW FLOW...PROBABLY NOT SAFE TO RULE OUT ADDITIONAL DEVELOPMENT FRIDAY...THOUGH NO STRONG SIGNALS FOR ORGANIZATION ARE PRESENT. TEMPS WILL BEGIN TO DROP SLIGHTLY AFTER THE FRONTAL PASSAGE THURSDAY MORNING. THE WARMEST DAY WILL BE WEDNESDAY...WITH MAX TEMPS AROUND 90 (A SOMEWHAT UNCERTAIN FORECAST GIVEN THE POSSIBILITY OF CLOUDS AND CONVECTION)...AND DEWPOINTS GETTING TO AROUND 70 OR EVEN THE LOWER 70S. HEAT INDICES WEDNESDAY SHOULD MAKE IT TO THE MID 90S...SHY OF ADVISORY CRITERIA BY SEVERAL DEGREES. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... BUILDING RIDGE OVER THE WESTERN UNITED STATES WILL CONTINUE TO CARVE OUT A TROUGH ACROSS THE EAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. THIS WILL KEEP TEMPERATURES FAIRLY SEASONABLE FRIDAY THROUGH MONDAY WITH HIGHS GENERALLY IN THE LOWER 80S. MODELS ARE SHOWING VARIOUS WEAK SHORT WAVES PROGRESSING THROUGH THE TROUGH BUT IT IS TOUGH TO PINPOINT ANY KIND OF TIMING. AS A RESULT...WITH THE UPPER LEVEL TROUGH IN PLACE AND GIVEN THE TIME OF YEAR...THINK THE BEST WAY TO GO IS TO TREND THE POPS DIURNAL BUT KEEP THEM ON THE LOW SIDE THROUGH THE WEEKEND. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 1750Z...ISOLATED SHOWERS AND THUNDERSTORMS ARE BEGINNING TO DEVELOP IN THE VICINITY OF AN OLD OUTFLOW BOUNDARY WHICH HAS BEEN SINKING SOUTHWARD ACROSS CENTRAL OHIO. NEAR-TERM HIGH RESOLUTION MODEL GUIDANCE SUGGESTS ACTIVITY WILL INCREASE THROUGH THE REMAINDER OF THE AFTERNOON IN A WARM AND UNSTABLE AIR MASS. HOWEVER WITH COVERAGE APPEARING SOMEWHAT SCATTERED...HAVE LEFT A VCTS IN THE TAFS SINCE THERE IS NO DEFINITIVE TIMING. DELAYED THE START OF THE VCTS AT THE CINCINNATI SITES SINCE ACTIVITY WILL HAVE TO PROPAGATE SOUTHEASTWARD...AND THERE IS SOME POSSIBILITY THAT MOST OF THE STORMS COULD BE TO THE EAST. IF A STORM DIRECTLY AFFECTS A TERMINAL...THEN BRIEF MVFR OR IFR CONDITIONS AND GUSTY WINDS COULD BE POSSIBLE. THIS ACTIVITY SHOULD DIE DOWN WITH LOSS OF DAYTIME HEATING THIS EVENING. THERE ARE NOW SEVERAL MODELS SUGGESTING A SECOND ROUND OF STORMS TIED TO AN UPPER LEVEL DISTURBANCE THAT MAY ENTER THE AREA AS A LINE OR CLUSTERS OF STORMS IN THE 04-08Z TIME FRAME. HOWEVER GIVEN THE UNCERTAINTY...JUST ADDED A VCTS AT THIS TIME. AFTERWARD THERE IS A LOW ENOUGH CHANCE OF PRECIPITATION TO KEEP THE TAFS DRY THROUGH WEDNESDAY MORNING...ALTHOUGH WINDS WILL BEGIN GUSTING NEAR 20KT BY MIDDAY. IN THE KCVG EXTENDED TAF...THUNDERSTORMS CAN BE EXPECTED TO INCREASE IN COVERAGE LATE WEDNESDAY AFTERNOON. OUTLOOK...THUNDERSTORMS LIKELY FROM WEDNESDAY AFTERNOON THROUGH THURSDAY. THUNDERSTORMS POSSIBLE...MAINLY AFTERNOON AND EVENING...FRIDAY AND SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM... SHORT TERM...HATZOS LONG TERM...JGL AVIATION...SNYDER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1014 AM EDT TUE JUN 25 2013 .SYNOPSIS... DISTURBANCES EMBEDDED IN WESTERLY FLOW ALOFT WILL INTERACT WITH A WARM AND UNSTABLE AIRMASS TO PROVIDE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE OHIO VALLEY THROUGH MID WEEK. THE GREATEST PRECIPITATION CHANCES WILL BE ON WEDNESDAY NIGHT...AS A COLD FRONT APPROACHES THE REGION. SLIGHTLY DRIER AND SLIGHTLY COOLER CONDITIONS ARE EXPECTED BY THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UNCERTAINTY CONTINUES IN REGARDS TO CONVECTIVE DEVELOPMENT THROUGH THE DAY. CLOUDS THINNING OUT THIS MORNING WILL RESULT IN ABUNDANT HEATING AND DESTABILIZATION. IT STILL APPEARS THAT STORMS WILL BE MOST ACTIVE IN A CORRIDOR EXTENDING FROM NORTHERN ILLINOIS INTO NORTHERN OHIO WHICH IS ALSO WHERE BETTER SHEAR IS FORECAST TO REMAIN. THESE STORMS COULD IMPACT THE FAR NORTHERN COUNTIES OF THE FORECAST AREA IN THE AFTERNOON AND HAVE MAINTAINED HIGHER CHANCE POPS THERE. ELSEWHERE STORM INITIATION IS MORE UNCERTAIN. PAST FEW RUNS OF THE HRRR AND RAP SUGGEST THAT ACTIVITY MAY NOT BE VERY EXTENSIVE NOR ORGANIZED. WITH FORCING VERY SUBTLE HAVE OPTED TO JUST BROAD BRUSH LOW END CHANCE POPS FOR NOW. FORECAST HIGHS LOOK REASONABLE AT THIS POINT. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... THE PRIMARY FOCUS FOR THE SHORT TERM WILL BE ON CONVECTION AHEAD OF A SHORTWAVE AND COLD FRONT ON WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. WEAK RIDGING OVER THE ILN CWA TONIGHT WILL BE UNLIKELY TO FAVOR NOCTURNAL CONVECTIVE DEVELOPMENT...WITH LLJ FORCING SETTING UP TO THE WEST. THOUGH A FEW CONVECTIVE ALLOWING MODELS DO SHOW UPSTREAM CONVECTION COMING INTO THE CWA (WHICH DOES SEEM REASONABLE GIVEN LINGERING INSTABILITY)...POPS WILL BE KEPT SOMEWHAT LOW DURING THE DIURNAL MIN (30 NW / 20 SE). ON WEDNESDAY...SOUTHWESTERLY FLOW OVER THE ILN CWA WILL INCREASE...AS MOISTURE TRANSPORT BEGINS TO RAMP UP JUST WEST OF THE CWA. A SHORTWAVE AND ASSOCIATED SURFACE LOW WILL BE MOVING ACROSS THE SOUTHERN GREAT LAKES. THE FORCING AHEAD OF THE SHORTWAVE SEEMS TO BE A BIT AHEAD OF THE ILL-DEFINED COLD FRONT TRAILING THE SURFACE LOW (WHICH WILL NOT LIKELY CROSS THE CWA UNTIL THURSDAY MORNING). THE OVERALL MODEL TREND SEEMS TO ALLOW FOR A SLIGHTLY QUICKER PASSAGE OF THE SHORTWAVE (WEDNESDAY AFTERNOON INTO WEDNESDAY OVERNIGHT) THAN IN PREVIOUS FORECASTS. WITH THIS FORECAST INCORPORATING THE PRESENCE (FINALLY) OF SOME WELL-DEFINED FORCING...AND EXPECTED UNSTABLE CONDITIONS (1500-2000 J/KG...PERHAPS UP TO 3000 J/KG IF UNINHIBITED BY CLOUDS OR PRECIPITATION DURING THE DAY)...LIKELY POPS HAVE BEEN INCLUDED FOR THE ENTIRE CWA. OF GREATER CONCERN IS THE INCREASING DYNAMICS WITH THE SYSTEM...AS WNW FLOW ALOFT COMBINES WITH A STRENGTHENING BAND OF LOW-LEVEL SOUTHWESTERLY FLOW TO CREATE A SHEARED ENVIRONMENT FAVORABLE FOR STORM ORGANIZATION. TOUGH TO RULE OUT ANY PARTICULAR TYPES OR MODES OF SEVERE WEATHER AT THIS POINT...AS THERE DOES APPEAR TO BE POTENTIAL FOR QUITE A BIT MORE THAN JUST THE RUN-OF-THE-MILL STRONG TO MARGINALLY SEVERE CONVECTION OF THE PAST FEW DAYS. THE HWO WORDING WILL BE REFINED A BIT FOR THIS THREAT...WHICH MAY CONTINUE INTO THE OVERNIGHT HOURS WEDNESDAY NIGHT. SEEING SOME HYDRO PARAMETERS LIGHT UP A BIT AS WELL (PWAT WELL OVER 1.50" AND GOOD MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE). THOUGH STORM ELEMENTS SHOULD BE SOMEWHAT PROGRESSIVE...SOME HEAVY RAIN WILL BE POSSIBLE. ANOTHER SHORTWAVE WILL IMPACT THE ILN CWA THURSDAY...THOUGH THE FORCING AHEAD OF THE MEAN TROUGH WILL GENERALLY BE EAST OF THE CWA. COOLING TEMPS ALOFT WILL HELP PROVIDE SOME INSTABILITY...SO CONVECTIVE CHANCES AGAIN EXIST THURSDAY (HIGHEST IN THE EASTERN CWA). IN THE WNW FLOW...PROBABLY NOT SAFE TO RULE OUT ADDITIONAL DEVELOPMENT FRIDAY...THOUGH NO STRONG SIGNALS FOR ORGANIZATION ARE PRESENT. TEMPS WILL BEGIN TO DROP SLIGHTLY AFTER THE FRONTAL PASSAGE THURSDAY MORNING. THE WARMEST DAY WILL BE WEDNESDAY...WITH MAX TEMPS AROUND 90 (A SOMEWHAT UNCERTAIN FORECAST GIVEN THE POSSIBILITY OF CLOUDS AND CONVECTION)...AND DEWPOINTS GETTING TO AROUND 70 OR EVEN THE LOWER 70S. HEAT INDICES WEDNESDAY SHOULD MAKE IT TO THE MID 90S...SHY OF ADVISORY CRITERIA BY SEVERAL DEGREES. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... BUILDING RIDGE OVER THE WESTERN UNITED STATES WILL CONTINUE TO CARVE OUT A TROUGH ACROSS THE EAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. THIS WILL KEEP TEMPERATURES FAIRLY SEASONABLE FRIDAY THROUGH MONDAY WITH HIGHS GENERALLY IN THE LOWER 80S. MODELS ARE SHOWING VARIOUS WEAK SHORT WAVES PROGRESSING THROUGH THE TROUGH BUT IT IS TOUGH TO PINPOINT ANY KIND OF TIMING. AS A RESULT...WITH THE UPPER LEVEL TROUGH IN PLACE AND GIVEN THE TIME OF YEAR...THINK THE BEST WAY TO GO IS TO TREND THE POPS DIURNAL BUT KEEP THEM ON THE LOW SIDE THROUGH THE WEEKEND. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... UPPER LEVEL FLOW WILL REMAIN ZONAL THROUGH THE TAF PERIOD. EMBEDDED DISTURBANCES WITHIN THIS FLOW WILL CONTINUE TO INTERACT WITH A MOIST AND UNSTABLE AIRMASS TO BRING A THREAT FOR SHOWERS AND THUNDERSTORMS. MODELS SUGGEST THAT AT LEAST SCATTERED CONVECTION WILL DEVELOP THIS AFTERNOON AND WILL LIKELY LINGER INTO THIS EVENING. GIVEN VARYING STORM EVOLUTION AND COVERAGE IN THE MODELS...HAVE BROAD BRUSHED THE TAFS WITH VCTS/CB UNTIL SIGNALS BECOME A LITTLE MORE CLEARER. STORMS WILL BE CAPABLE OF CONTAINING BRIEF HEAVY RAIN WITH MVFR CIGS AND IFR VSBYS. FOR TONIGHT...PREVIOUS THINKING WAS THE PERHAPS CONVECTION WOULD SHIFT SOMEWHAT TO THE NORTH AND STAY FOCUSED MORE ACROSS THE SRN GREAT LAKES. SOME LATER MODEL RUNS SUGGEST THAT PERHAPS CONVECTION MAY NOW SEEP SOUTH INTO THE REGION...ESPECIALLY NEAR THE NORTHERN TAF SITES. GIVEN LOW CONFIDENCE...HAVE KEPT THE TAFS DRY FOR NOW. OUTLOOK...THUNDERSTORMS EXPECTED FROM WEDNESDAY AFTERNOON THROUGH THURSDAY. THUNDERSTORMS POSSIBLE...MAINLY AFTERNOON AND EVENING...FRIDAY AND SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM... SHORT TERM...HATZOS LONG TERM...JGL AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1134 PM EDT WED JUN 26 2013 .SYNOPSIS... A SERIES OF UPPER LEVEL WAVES DIVING DOWN THE FRONT-SIDE OF INTENSIFYING FOUR CORNERS RIDGE WILL CARVE OUT AN UNSEASONABLY DEEP TROUGH OVER THE GREAT LAKES REGION THROUGH THE END OF THE WEEK. THIS PATTERN WILL FEATURE SLIGHTLY COOLER TEMPERATURES AND SEVERAL OPPORTUNITIES FOR RAINFALL...SOME OF WHICH MAY BE LOCALLY HEAVY. THE UNSETTLED WEATHER REGIME WILL LIKELY PERSIST INTO THE FIRST WEEK OF JULY BEFORE THE UPPER TROUGH AXIS SLOWLY MIGRATES WESTWARD INTO THE UPPER MIDWEST. && .NEAR TERM /UNTIL 9 AM THURSDAY MORNING/... FORECAST AREA DEVOID OF ALL SHOWERS NOW. DIGGING SHORT WAVE TROUGH OVER LOWER MI/IN IS SPINNING THE PRECIP OVER OH MORE TO THE N THAN EAST RIGHT NOW. THUS...PRECIP TIMING MAINLY AFTER 09Z IN THE WESTERN MTS LOOKING SOLID. HRRR A LITTLE SLOWER STILL...AND CAN SEE THAT HAPPENING AS THROUGH DIGS AND HEIGHTS LOWER. BLOW OFF FROM ANVILS OF CONVECTION TO THE WEST WILL START TO COVER THE WRN MTS WTHROUGH THE NIGHT. OHERWISE...AREAS OF FOG SHOULD OCCUR IN THE COOLER VALLEYS AND IN THE FAR SE WHERE IT DID RAIN THIS EVENING AND DEWPOINTS ARE STILL CLOSE TO 70F. && .SHORT TERM /9 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... SURGE OF SUBTROPICAL MOISTURE AND FAVORABLE LARGE SCALE FORCING WILL PUT THE REGION UNDER THE GUN FOR LOCALLY HEAVY SHOWERS AND THUNDERSTORMS...WITH 2.0 INCH PW OR GREATER INDICATED BY OPERATIONAL RUNS AND ENSEMBLES THU AFTERNOON. HEAVIER RAINFALL ON TUESDAY NIGHT OVER PBZ AREA PROMPTED ISSUANCE OF FFA FOR AREAS BORDERING MY WESTERN COUNTIES. HEAVY RAIN THREAT OVER CENTRAL PA IS THERE...BUT LOCAL 1 TO 2 INCH AMOUNTS OVER THE WEST AND LESS THAN 0.5 INCH AMOUNTS ACROSS THE SE LEAVES US WITH HIGHER FFG GUIDANCE ON THU. LITTLE TO NO RAIN WED AS WELL A DETRIMENT TO FLOODING WITH AN ENTIRE DAY OF DRYING. LOCATION OF HEAVIEST RAINFALL IS STILL IN QUESTION IF YOU LOOK AT THE LATEST WPC MDLS. PW ANOMALIES SUGGEST THE SOUTH STANDS THE GREAT CHANCE OF SEEING EXCESSIVE RAINFALL...BUT THESE AREAS HAVE BEEN RELATIVELY DRIER THAN THE REST OF MY CWA OVER THE LAST 24-48 HOURS. THEREFORE CONFIDENCE ON PLACEMENT IS LOW AT THIS TIME...BUT WILL CONTINUE TO HIGHLIGHT THE HEAVY RAIN THREAT IN THE HWO PRODUCT AND HAVE KEPT HEAVY RAINFALL AND MARGINAL SVR THUNDERSTORM WORDING FOR THE DAYTIME PERIOD THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... UPPER LEVEL TROUGH MOVING A MID AND LOW LEVEL LOW THROUGH THE REGION TOMORROW AFTERNOON AND EVENING. HGT FALLS ASSOCD WITH THE AMPLIFYING TROUGH WILL RESULT IN A STRENGTHENING SFC LOW LIFTING NEWD FM OH ACRS CNTRL PA INTO UPSTATE NY BY FRIDAY. IT APPEARS THIS LOW WILL BE ACCOMPANIED BY A MESOSCALE CONVECTIVE COMPLEX /MCC/ THAT WILL MOVE TO THE NORTHEAST LATE THURSDAY. THE GUIDANCE SLIGHTLY DIVERGES ON THE TIMING/TRACK OF THE MCC BUT THE BIGGEST DIVERGENCE IS IN THE QPF LOCATION AND AMOUNT. THE EC AND GFS KEEP THE HIGHEST PRECIPITATION ALONG THE NW MTNS AND ALONG THE FRONTAL BOUNDARY THAT DEVELOPS ACROSS THE NORTHERN TWO-THIRDS OF THE STATE. THE NAM BRINGS 1.5 INCHES OF PRECIP FROM THE SOUTHWEST TO THE NORTHEAST ACROSS PA. HAVE LEFT BROAD POPS AND QPF AMOUNTS ACROSS THE NORTHERN PORTION OF THE CWA. EXPECT MORE WIDESPREAD PRECIPITATION WITH THIS EVENT. A BROAD CYCLONIC/NWLY MID-UPPER FLOW WILL BE IN PLACE BY DAY 3/FRI WITH A UNSEASONABLY LOW/BELOW NORMAL HGTS COVERING MUCH OF THE ERN U.S. THIS PATTERN IS TYPICALLY FAVORABLE FOR DIURNAL CONVECTION GIVEN RELATIVELY STEEP LAPSE RATES/COLD TEMPS ALOFT. TRAILING ENERGY DIGGING INTO THE BACK-SIDE OF THE MEAN TROUGH WILL SUPPORT UNSETTLED CONDS...BUT LIMITED MSTR/NEAR NORMAL PWATS SHOULD HELP CONTAIN BASIN AVG RAFL AMTS. DAY/NIGHTTIME TEMPS WILL FALL BACK NEAR OR PERHAPS SLIGHTLY BELOW LATE JUNE NORMALS. THE 26/12Z GLOBAL NUMERICAL MODEL AND ENSEMBLE GUIDANCE CONTINUE TO SHOW GOOD AGREEMENT CONCERNING THE LARGE SCALE PATTERN THROUGH THE MEDIUM RANGE AND EXTENDED FCST PERIOD. THESE DATA SHOW A GRADUAL WWD MIGRATION OR RETROGRESSION OF THE AMPLIFIED TROUGH- RIDGE TROUGH-RIDGE CONFIGURATION FROM THE NERN PACIFIC/GREAT BASIN/GREAT LAKES/WRN ATLC. THE SLIGHTLY COOLER AND UNSETTLED SENSIBLE WEATHER TREND INITIATING FROM THE MID-LATE WEEK PERIOD IS EXPECTED TO CONTINUE THRU THE WEEKEND AND INTO NEXT WEEK. IN THE MEDIUM RANGE FCST THERE IS THE SLIGHT WWD SHIFT IN THE MEAN TROUGH AXIS...WHICH WOULD ALLOW WARMER...MORE HUMID AIR EAST OF THE APPLCHNS TO RETURN TO THE AREA EARLY NEXT WEEK. A NEARLY-STATIONARY N-S FRONTAL ZONE ALONG THE ERN FLANKS OF THE UPPER-LEVEL TROUGH /CENTERED INVOF 90W/ STILL LOOKS TO BE ACTIVE AND PROVIDES A FOCUS FOR SHOWERS/TSTMS. OVERALL MADE ONLY MINOR CHANGES TO THE PREVIOUS FCST. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... AREA CLEAR OF SHOWERS NOW. MAIN CONCERN OVERNIGHT WILL BE FOG...MAIN AREA NEAR BFD...WHERE TEMP FCST TO DROP TO OR JUST BELOW THE DEWPOINT. MDT AND LNS HAVE THE NEXT BEST CHC FOR FOG...GIVEN STORMS THERE EARLIER. EXPECT FOG TO BURN OFF THU AM...GIVEN EARLY SUNRISE TIMES. FOR NOW...LIKE LAST NIGHT...JUST FORECASTING VFR THU WITH VCSH FROM MID DECK. AT LEAST THIS WORKED OUT TODAY FOR PART OF THE AREA. THINKING IS MOST OF THE SIGNIFICANT CONVECTION THIS EVENING WILL DROP SE ACROSS OH VLY... SW OF OUR AREA...HELPING TO KEEP THE BULK OF THE SIGNIFICANT STORMS SOUTH OF OUR AREA ON THU. SO FAR...THIS HAS BEEN THE CASE...COLDEST TOPS SW OF AREA NOW. OVERALL...HARD TO SEE ANY ONE CLEAR CUT DAYS WITH DRY CONDITIONS INTO THE WEEKEND...GIVEN SYSTEMS ROTATING AROUND EASTERN NA UPPER LVL LOW. RIDGE OFF EAST COAST NEXT WEEK COULD CAUSE THE COLD FRONT TO STALL AND EVEN BACK WESTWARD... THUS WILL KEEP A CHC OF SHOWERS INTO MONDAY. OUTLOOK... FRI-MON...SHOWERS AND STORMS TO PREVAIL AT TIMES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR NEAR TERM...DANGELO SHORT TERM...DEVOIR LONG TERM...CERU/STEINBUGL AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1025 PM EDT WED JUN 26 2013 .SYNOPSIS... A SERIES OF UPPER LEVEL WAVES DIVING DOWN THE FRONT-SIDE OF INTENSIFYING FOUR CORNERS RIDGE WILL CARVE OUT AN UNSEASONABLY DEEP TROUGH OVER THE GREAT LAKES REGION THROUGH THE END OF THE WEEK. THIS PATTERN WILL FEATURE SLIGHTLY COOLER TEMPERATURES AND SEVERAL OPPORTUNITIES FOR RAINFALL...SOME OF WHICH MAY BE LOCALLY HEAVY. THE UNSETTLED WEATHER REGIME WILL LIKELY PERSIST INTO THE FIRST WEEK OF JULY BEFORE THE UPPER TROUGH AXIS SLOWLY MIGRATES WESTWARD INTO THE UPPER MIDWEST. && .NEAR TERM /UNTIL 9 AM THURSDAY MORNING/... FORECAST AREA DEVOID OF ALL SHOWERS NOW. DIGGING SHORT WAVE TROUGH OVER LOWER MI/IN IS SPINNING THE PRECIP OVER OH MORE TO THE N THAN EAST RIGHT NOW. THUS...PRECIP TIMING MAINLY AFTER 09Z IN THE WESTERN MTS LOOKING SOLID. HRRR A LITTLE SLOWER STILL...AND CAN SEE THAT HAPPENING AS THROUGH DIGS AND HEIGHTS LOWER. BLOW OFF FROM ANVILS OF CONVECTION TO THE WEST WILL START TO COVER THE WRN MTS WTHROUGH THE NIGHT. OHERWISE...AREAS OF FOG SHOULD OCCUR IN THE COOLER VALLEYS AND IN THE FAR SE WHERE IT DID RAIN THIS EVENING AND DEWPOINTS ARE STILL CLOSE TO 70F. && .SHORT TERM /9 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... SURGE OF SUBTROPICAL MOISTURE AND FAVORABLE LARGE SCALE FORCING WILL PUT THE REGION UNDER THE GUN FOR LOCALLY HEAVY SHOWERS AND THUNDERSTORMS...WITH 2.0 INCH PW OR GREATER INDICATED BY OPERATIONAL RUNS AND ENSEMBLES THU AFTERNOON. HEAVIER RAINFALL ON TUESDAY NIGHT OVER PBZ AREA PROMPTED ISSUANCE OF FFA FOR AREAS BORDERING MY WESTERN COUNTIES. HEAVY RAIN THREAT OVER CENTRAL PA IS THERE...BUT LOCAL 1 TO 2 INCH AMOUNTS OVER THE WEST AND LESS THAN 0.5 INCH AMOUNTS ACROSS THE SE LEAVES US WITH HIGHER FFG GUIDANCE ON THU. LITTLE TO NO RAIN WED AS WELL A DETRIMENT TO FLOODING WITH AN ENTIRE DAY OF DRYING. LOCATION OF HEAVIEST RAINFALL IS STILL IN QUESTION IF YOU LOOK AT THE LATEST WPC MDLS. PW ANOMALIES SUGGEST THE SOUTH STANDS THE GREAT CHANCE OF SEEING EXCESSIVE RAINFALL...BUT THESE AREAS HAVE BEEN RELATIVELY DRIER THAN THE REST OF MY CWA OVER THE LAST 24-48 HOURS. THEREFORE CONFIDENCE ON PLACEMENT IS LOW AT THIS TIME...BUT WILL CONTINUE TO HIGHLIGHT THE HEAVY RAIN THREAT IN THE HWO PRODUCT AND HAVE KEPT HEAVY RAINFALL AND MARGINAL SVR THUNDERSTORM WORDING FOR THE DAYTIME PERIOD THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... UPPER LEVEL TROUGH MOVING A MID AND LOW LEVEL LOW THROUGH THE REGION TOMORROW AFTERNOON AND EVENING. HGT FALLS ASSOCD WITH THE AMPLIFYING TROUGH WILL RESULT IN A STRENGTHENING SFC LOW LIFTING NEWD FM OH ACRS CNTRL PA INTO UPSTATE NY BY FRIDAY. IT APPEARS THIS LOW WILL BE ACCOMPANIED BY A MESOSCALE CONVECTIVE COMPLEX /MCC/ THAT WILL MOVE TO THE NORTHEAST LATE THURSDAY. THE GUIDANCE SLIGHTLY DIVERGES ON THE TIMING/TRACK OF THE MCC BUT THE BIGGEST DIVERGENCE IS IN THE QPF LOCATION AND AMOUNT. THE EC AND GFS KEEP THE HIGHEST PRECIPITATION ALONG THE NW MTNS AND ALONG THE FRONTAL BOUNDARY THAT DEVELOPS ACROSS THE NORTHERN TWO-THIRDS OF THE STATE. THE NAM BRINGS 1.5 INCHES OF PRECIP FROM THE SOUTHWEST TO THE NORTHEAST ACROSS PA. HAVE LEFT BROAD POPS AND QPF AMOUNTS ACROSS THE NORTHERN PORTION OF THE CWA. EXPECT MORE WIDESPREAD PRECIPITATION WITH THIS EVENT. A BROAD CYCLONIC/NWLY MID-UPPER FLOW WILL BE IN PLACE BY DAY 3/FRI WITH A UNSEASONABLY LOW/BELOW NORMAL HGTS COVERING MUCH OF THE ERN U.S. THIS PATTERN IS TYPICALLY FAVORABLE FOR DIURNAL CONVECTION GIVEN RELATIVELY STEEP LAPSE RATES/COLD TEMPS ALOFT. TRAILING ENERGY DIGGING INTO THE BACK-SIDE OF THE MEAN TROUGH WILL SUPPORT UNSETTLED CONDS...BUT LIMITED MSTR/NEAR NORMAL PWATS SHOULD HELP CONTAIN BASIN AVG RAFL AMTS. DAY/NIGHTTIME TEMPS WILL FALL BACK NEAR OR PERHAPS SLIGHTLY BELOW LATE JUNE NORMALS. THE 26/12Z GLOBAL NUMERICAL MODEL AND ENSEMBLE GUIDANCE CONTINUE TO SHOW GOOD AGREEMENT CONCERNING THE LARGE SCALE PATTERN THROUGH THE MEDIUM RANGE AND EXTENDED FCST PERIOD. THESE DATA SHOW A GRADUAL WWD MIGRATION OR RETROGRESSION OF THE AMPLIFIED TROUGH- RIDGE TROUGH-RIDGE CONFIGURATION FROM THE NERN PACIFIC/GREAT BASIN/GREAT LAKES/WRN ATLC. THE SLIGHTLY COOLER AND UNSETTLED SENSIBLE WEATHER TREND INITIATING FROM THE MID-LATE WEEK PERIOD IS EXPECTED TO CONTINUE THRU THE WEEKEND AND INTO NEXT WEEK. IN THE MEDIUM RANGE FCST THERE IS THE SLIGHT WWD SHIFT IN THE MEAN TROUGH AXIS...WHICH WOULD ALLOW WARMER...MORE HUMID AIR EAST OF THE APPLCHNS TO RETURN TO THE AREA EARLY NEXT WEEK. A NEARLY-STATIONARY N-S FRONTAL ZONE ALONG THE ERN FLANKS OF THE UPPER-LEVEL TROUGH /CENTERED INVOF 90W/ STILL LOOKS TO BE ACTIVE AND PROVIDES A FOCUS FOR SHOWERS/TSTMS. OVERALL MADE ONLY MINOR CHANGES TO THE PREVIOUS FCST. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... MOST OF THE AREA CLEAR OF SHOWERS AND STORMS NOW. ONE STORM LEFT JUST SE OF LNS. MAIN CONCERN OVERNIGHT WILL BE FOG...MAIN AREA NEAR BFD... WHERE TEMP FCST TO DROP TO OR JUST BELOW THE DEWPOINT. MDT AND LNS HAVE THE NEXT BEST CHC FOR FOG...GIVEN STORMS THERE EARLIER. EXPECT FOG TO BURN OFF THU AM...GIVEN EARLY SUNRISE TIMES. FOR NOW...LIKE LAST NIGHT...JUST FORECASTING VFR THU WITH VCSH FROM MID DECK. AT LEAST THIS WORKED OUT TODAY FOR PART OF THE AREA. THINKING IS MOST OF THE SIGNIFICANT CONVECTION THIS EVENING WILL DROP SE ACROSS OH VLY... SW OF OUR AREA...HELPING TO KEEP THE BULK OF THE SIGNIFICANT STORMS SOUTH OF OUR AREA ON THU. OVERALL...HARD TO SEE ANY ONE CLEAR CUT DAYS WITH DRY CONDITIONS INTO THE WEEKEND...GIVEN SYSTEMS ROTATING AROUND EASTERN NA UPPER LVL LOW. RIDGE OFF EAST COAST NEXT WEEK COULD CAUSE THE COLD FRONT TO STALL AND EVEN BACK WESTWARD... THUS WILL KEEP A CHC OF SHOWERS INTO MONDAY. OUTLOOK... FRI-MON...SHOWERS AND STORMS TO PREVAIL AT TIMES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR NEAR TERM...DANGELO SHORT TERM...DEVOIR LONG TERM...CERU/STEINBUGL AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS SPOKANE WA
203 PM PDT Tue Jun 25 2013 .SYNOPSIS... A wet pattern continues across the Inland Northwest through mid week, with occasional showers and the potential for thunderstorms. The latter half of the week, into early next week, will be dramatically different. Expect a quick warming, drying trend with temperatures moving to above normal, summer like values. && .DISCUSSION... Tonight: The upper level shortwave that moved through the Columbia Basin early today is now pivoting across the ID Panhandle and into the Northeast Mountains. This disturbance is expected to push north of the region by the evening hours; however, there is another weaker disturbance set to move in behind this wave for late this afternoon into the late evening hours. Models show some weak upper level instability ahead of this next wave. The best instability looks to be from the Northeast Mountains to the Central Panhandle Mountains and points southeastward, as well as northwest of a line from Moses Lake to Sandpoint. These are the two areas that HRRR focuses showers for this evening into the early portions of tonight. There does not appear to be enough instability for thunderstorms once we lose our surface heating, but we should continue to see isolated to scattered thunderstorms across much of the Panhandle into the early evening hours (especially from the Northeast Blue Mountains into the Central Panhandle Mountains). These thunderstorms will be capable of heavy rain possibly mixed in with some small hail and gusty outflow winds. We will also see a little bit of clearing behind this next wave with a narrow dry slot showing up on the water vapor satellite imagery. With dew point temps remaining in the low 50s, it will not take much cooling for fog to redevelop in the valleys of extreme eastern WA and the ID Panhandle late tonight into early Wednesday morning, especially across the mountain valleys. /SVH Wednesday through Friday night: Expect lingering shower chances, especially in the afternoon and early evening hours, before a ridge of high pressure begins to build over the West by the end of the work week. Between Wednesday and Thursday evening the jet stream bisecting the Inland Northwest slowly migrates north. Impulses/vorticity maxima littering the west-southwest flow ride through on this jet, keeping the shower chances alive. The precise timing and track of individual impulses is not agreed upon, decreasing confidence in what areas have the overall best chance of showers. On Wednesday loose model agreement places the highest concentration around the mountains, though all areas will have at least slight chances through the evening. Coverage decreases through Wednesday evening and the overnight, with the main chances retreating to the Cascades and eastern mountains. By Thursday afternoon the threat of showers increases again. However with the jet starting to lift north through this period the overall threat will be less as compared to Wednesday. The threat of thunderstorms is not all that great given depicted convective instability. But a few cannot be ruled out across the northern-tier, largely north of Highway 2, as well a across the Blue Mountains through central Panhandle Mountains during the afternoon/early evening hours. By Thursday night into Friday night the ridge begins to amplify over the region from the south to southeast and the jet axis lifts north through B.C., leading to an overall drying trend. A few models still keep a slight risk of showers going near the Cascades and near the Canadian border, as well as closer to the Blue Mountains, for Friday afternoon but the overall risk is too small at this time to put a mention in the official forecast. This should also be the beginning of the more pronounced warming trend. Regional 850mb temperatures warm into the upper teens to lower 20s. This supports highs about 10 degrees above normal. /J. Cote` Saturday through Tuesday: This period will be hot and dry. The region will under a ridging pattern from the high pressure located in the Southwest US. The strength of the ridge will keep a Low off the NW Pacific Coast from coming onshore. Temperatures in the region are expected to be 10 to 15 degrees above normal. Most places will see the high temperatures into 80s to 90s with a few places possibly reaching 100. On Saturday, the mid level moisture mixed with the high temperatures could produce an isolated thunderstorm in the high elevations of the mountains. As drier conditions continue through the weekend, the chances for these storms diminishes. /JDC && .AVIATION... 00Z TAFS: A shortwave is currently exiting the region bringing an isolated thunderstorms in the Northern ID Panhandle and rainshowers to the KCOE area. Rainshowers are possible throughout the evening in the KLWS and KPUW area. VFR conditions are expected for the region in the early morning hours until early afternoon when another shortwave is expected to pass through the region. Some of these showers can become thunderstorms with the surface heating throughout the afternoon. /JDC && .PRELIMINARY POINT TEMPS/POPS... Spokane 51 71 54 78 57 87 / 40 40 20 20 0 0 Coeur d`Alene 51 70 53 78 54 86 / 30 40 30 20 0 0 Pullman 52 72 52 79 54 85 / 80 40 30 10 0 0 Lewiston 57 80 59 88 61 93 / 80 40 20 10 0 0 Colville 51 73 51 82 52 90 / 60 40 20 20 10 0 Sandpoint 50 69 50 77 50 87 / 60 50 20 20 10 0 Kellogg 49 67 51 76 55 90 / 60 50 30 20 0 0 Moses Lake 55 77 58 86 60 90 / 40 20 10 10 0 0 Wenatchee 55 76 60 83 63 88 / 50 20 10 10 0 0 Omak 51 74 54 82 57 89 / 70 30 20 20 10 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
434 AM PDT Tue Jun 25 2013 .SYNOPSIS... A wet pattern will continue across the Inland Northwest through mid week...with frequent showers and the potential for thunderstorms. The weather the second half of the week will be dramatically different as a warming and drying trend quickly develops by late week. Summer-like temperatures will be likely as we move towards the end of the week. && .DISCUSSION... Today and tonight...Little if any change to the longwave pattern consisting of large longwave trof offshore up against inland ridging which continues to funnel through negatively tilted disturbances tied into moderate and effective sources of moisture. The end result is another fairly wet forecast for today that shows some improvement after 11 pm tonight but still not yet enough to dry it out totally as per the latest GFS with a number of this morning`s HRRR model runs support this solution. Otherwise with such abundant moisture lingering from past and present rainfall some low clouds and fog may get mentioned at times in the mix. Minor change was removal of thunderstorm mention near the cascades as lapse rates don`t appear to be steep enough to support it there but have left minor mention for afternoon and evening further east closer to Spokane and vicinity and the North Idaho Panhandle. /Pelatti Wed through Sat morning: Following what should be our last day of meaningful chances of pcpn on Wed into Wed Nt will be a rapid warming and drying trend beginning Thurs. This pcpn chance Wed should not be too widespread, but certainly heaviest during the afternoon and evening as the region remains under a long-fetch moisture plume drifting north. This pcpn threat will last into Thurs morning. Though not currently in the fcst, there could be an isolated threat of thunder Wed afternoon across NE Wa as well as near the Camas Prairie and Nrn Blue Mtns of Wa. One note of interest concerning pcpn chances Fri Nt: The GFS advects of plume of elevated instability above about 700mb north through Oregon and into SE Wa Fri Nt. The RH in this layer a rather dry, and the GFs is the only model guidance that produces nocturnal pcpn (very light and spotty). We did not put any of this pcpn in the fcst, but it`s something to watch. 500mb ht rises close of 150-200m, accompanying 850mb temp rises around 10c, will push hi temps nearly 10F above normal by Fri. bz Saturday through Tuesday...An upper level ridge will amplify dramatically over the Inland Northwest through early next week, with the result being the hottest temperatures we`ve seen so far this early summer season (it`s still very early). All the gnashing of teeth regarding the recent rainfall and cool temperatures will stop as temperatures will warm well into the 80s and 90s, with isolated locations approaching the century mark. The extended models produce high temperatures that are 15+ above normal. Had it not been for the recent soaking rainfalls the hot temperatures may not be as hard to realize. But since many areas have received their June`s average total rainfall over the last week, afternoon temperatures should remain below the hottest of the guidance numbers. At least through the weekend. If the ridge continues to amplify next week, enough drying at the surface would allow for even higher temperatures. ty && .AVIATION... 12Z TAFS: A moist and slightly unstable flow from the southwest will continue to steer small scale disturbances over the aviation area today and into the evening. MVFR ceilings and visibilities mostly due to low level clouds and fog associated with the abundant low level moisture left due to yesterdays and todays rainfall. Otherwise some low MVFR ceilings may be associated with the showers and/or thunderstorms. /Pelatti && .PRELIMINARY POINT TEMPS/POPS... Spokane 65 52 73 54 79 57 / 90 50 30 10 0 0 Coeur d`Alene 65 52 72 53 79 54 / 90 50 30 10 0 0 Pullman 65 53 73 54 81 53 / 80 50 40 10 0 0 Lewiston 73 57 81 58 89 60 / 80 60 40 20 0 0 Colville 69 52 74 53 82 53 / 90 60 40 20 0 0 Sandpoint 66 51 71 52 77 50 / 90 60 40 20 0 0 Kellogg 63 50 69 52 77 56 / 90 60 30 20 0 0 Moses Lake 70 57 78 58 86 59 / 70 20 10 10 0 0 Wenatchee 70 55 77 60 84 63 / 80 20 20 10 0 0 Omak 70 53 76 54 82 57 / 80 30 20 10 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
236 AM PDT Tue Jun 25 2013 .SYNOPSIS... A wet pattern will continue across the Inland Northwest through mid week...with frequent showers and the potential for thunderstorms. The weather the second half of the week will be dramatically different as a warming and drying trend quickly develops by late week. Summer-like temperatures will be likely as we move towards the end of the week. && .DISCUSSION... Today and tonight...Little if any change to the longwave pattern consisting of large longwave trof offshore up against inland ridging which continues to funnel through negatively tilted disturbances tied into moderate and effective sources of moisture. The end result is another fairly wet forecast for today that shows some improvement after 11 pm tonight but still not yet enough to dry it out totally as per the latest GFS with a number of this morning`s HRRR model runs support this solution. Otherwise with such abundant moisture lingering from past and present rainfall some low clouds and fog may get mentioned at times in the mix. Minor change was removal of thunderstorm mention near the cascades as lapse rates don`t appear to be steep enough to support it there but have left minor mention for afternoon and evening further east closer to Spokane and vicinity and the North Idaho Panhandle. /Pelatti Wed through Sat morning: Following what should be our last day of meaningful chances of pcpn on Wed into Wed Nt will be a rapid warming and drying trend beginning Thurs. This pcpn chance Wed should not be too widespread, but certainly heaviest during the afternoon and evening as the region remains under a long-fetch moisture plume drifting north. This pcpn threat will last into Thurs morning. Though not currently in the fcst, there could be an isolated threat of thunder Wed afternoon across NE Wa as well as near the Camas Prairie and Nrn Blue Mtns of Wa. One note of interest concerning pcpn chances Fri Nt: The GFS advects of plume of elevated instability above about 700mb north through Oregon and into SE Wa Fri Nt. The RH in this layer a rather dry, and the GFs is the only model guidance that produces nocturnal pcpn (very light and spotty). We did not put any of this pcpn in the fcst, but it`s something to watch. 500mb ht rises close of 150-200m, accompanying 850mb temp rises around 10c, will push hi temps nearly 10F above normal by Fri. bz Saturday through Tuesday...An upper level ridge will amplify dramatically over the Inland Northwest through early next week, with the result being the hottest temperatures we`ve seen so far this early summer season (it`s still very early). All the gnashing of teeth regarding the recent rainfall and cool temperatures will stop as temperatures will warm well into the 80s and 90s, with isolated locations approaching the century mark. The extended models produce high temperatures that are 15+ above normal. Had it not been for the recent soaking rainfalls the hot temperatures may not be as hard to realize. But since many areas have received their June`s average total rainfall over the last week, afternoon temperatures should remain below the hottest of the guidance numbers. At least through the weekend. If the ridge continues to amplify next week, enough drying at the surface would allow for even higher temperatures. ty && .AVIATION... 06Z TAFS: An exiting weather system will leave some remaining moisture and residual showers overnight. As a result, we will continue to see the possibility of MVFR cigs and vis at times overnight with the threat of valley fog especially north of Interstate 90 through 17Z Tuesday. Another moisture surge moves into the Cascades with a round of showers progressing from southwest to northeast through the day on Tuesday. There will also be a possibility of isolated thunderstorms and localized MVFR ceilings late Tuesday morning into Tuesday afternoon. TC && .PRELIMINARY POINT TEMPS/POPS... Spokane 65 52 73 54 79 57 / 90 50 30 10 0 0 Coeur d`Alene 65 52 72 53 79 54 / 90 50 30 10 0 0 Pullman 65 53 73 54 81 53 / 80 50 40 10 0 0 Lewiston 73 57 81 58 89 60 / 80 60 40 20 0 0 Colville 69 52 74 53 82 53 / 90 60 40 20 0 0 Sandpoint 66 51 71 52 77 50 / 90 60 40 20 0 0 Kellogg 63 50 69 52 77 56 / 90 60 30 20 0 0 Moses Lake 70 57 78 58 86 59 / 70 20 10 10 0 0 Wenatchee 70 55 77 60 84 63 / 80 20 20 10 0 0 Omak 70 53 76 54 82 57 / 80 30 20 10 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1050 PM CDT WED JUN 26 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 847 PM CDT WED JUN 26 2013 WILL BE UPDATING PCPN TRENDS SHORTLY. ALTHOUGH CONVECTION HAS WEAKENED DUE TO DECREASING INSTABILITY...ADDITIONAL DEVELOPMENT WAS OCCURRING OVER NC WI...IN THE LFQ OF A 90-100 KT JET STREAK. ISOLATED CONVECTION WAS ALSO NOTED ACROSS FAR NORTHEAST ND AND NORTHERN MN...IN ASSOCIATION WITH A COUPLE S/W TROFS. CURRENT FCST HAS PCPN ENDING AFTER MIDNIGHT...BUT SUSPECT THAT AT LEAST ISOLD SHRA/TSRA WILL NEED TO BE KEPT IN THE FCST OVERNIGHT. PARTLY CLOUDY SKIES AND LIGHT WINDS WILL LEAD TO ANOTHER ROUND OF FOG OVERNIGHT. THE THICKEST FOG SHOULD OCCUR OVER NC/NE WI... WHERE THE MOST SIGNIFICANT RAINFALL OCCURRED THIS AFTERNOON AND EVENING. && .SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 225 PM CDT WED JUN 26 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ELONGATED SHORTWAVE TROUGH SPINNING OVER THE LAKE WINNIPEG REGION WHICH ALSO EXTENDS SOUTH INTO THE NORTHERN MISSISSIPPI VALLEY. ANOTHER SHORTWAVE IS SPINNING OVER NORTHERN ILLINOIS AND IS HEADING EAST...SO NOT MUCH IMPACT ACROSS OUR AREA. STORMS FIRED UP AROUND MIDDAY ALONG A SURFACE TROUGH OVER THE WI/MN BORDER WHERE ML CAPES ARE REACHING UP TO 2K J/KG. THE FIRST WARNING THIS AFTERNOON WAS JUST ISSUED A FEW MINUTES AGO...BUT STORMS ARE NOT SHOWING MUCH ORGANIZATION AND 0-6KM BULK SHEAR VALUES ARE RATHER POOR AT AROUND 20 KTS. WITH SUCH WEAK BULK SHEAR VALUES...THINKING PULSY SEVERE AT THIS TIME UNLESS STORMS CAN BECOME MORE ORGANIZED. A FEW SPOTTY SHOWERS TRIED TO DEVELOP OVER NORTH-CENTRAL AND FAR NORTHEAST WISCONSIN...BUT FIZZLED OUT. SEVERE WEATHER CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LATEST TIMING HAS STORMS ARRIVING INTO NORTH-CENTRAL WISCONSIN AT AROUND 21Z AND PROGRESSING EAST TO NORTHEAST WISCONSIN BY 00-01Z BEFORE EXITING AFTER 04Z. WITH STORMS ARRIVING AT OR NEAR PEAK HEATING...SEVERE WEATHER HAS POTENTIAL TO REACH NORTHEAST WISCONSIN THOUGH CAPES ARE NOT NEARLY AS IMPRESSIVE OVER NORTHEAST AND EAST-CENTRAL WISCONSIN AS FURTHER WEST. WITH LOSS OF HEATING AND WEAKER INSTABILITY...THINK SEVERE THREAT OVER THE EASTERN PARTS OF THE STATE ARE VERY MARGINAL. BETTER CHANCES WILL BE OVER NORTH-CENTRAL WISCONSIN. ONCE THE STORMS DEPARTS/WEAKEN...RATHER JUICY AIRMASS WILL LINGER FOR THE REST OF THE NIGHT. AREAS THAT RECEIVED RAIN WILL BE PRIME CANDIDATES FOR DENSE FOG AND WILL ADD FOG TO THE FORECAST. LOWS MAINLY IN THE LOW TO MID 60S. THURSDAY...THE UPPER TROUGH OVER LAKE WINNIPEG WILL SLIDE SOUTHEAST INTO LAKE SUPERIOR. WILL HAVE SUPPORT IN THE FORM OF UPPER DIVERGENCE IN THE LEFT FRONT QUAD OF THE JET STREAK FOR MUCH OF THE DAY...SO CANNOT RULE OUT SPOTTY SHOWERS AND STORMS IN THE MORNING. BUT THINKING STORMS ARE LIKELY FOR MOST OF NORTH-CENTRAL AND NORTHEAST WISCONSIN IN THE AFTERNOON...ONCE UPWARDS OF 1500 J/KG OF ML CAPE CAN DEVELOP ACCORDING TO PROGGED SOUNDINGS. WITH DEEP MIXING AND 0-6KM BULK SHEAR AROUND 30KTS...THINK SEVERE WEATHER IS POSSIBLE TOMORROW AFTERNOON. DAMAGING WIND GUSTS AND LARGE HAIL WILL BE THE MAIN THREATS. SHOULD FEEL LESS HUMID OUT THERE THAN TODAY...BUT HIGHS SHOULD STILL REACH INTO THE LOW TO MID 80S. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 225 PM CDT WED JUN 26 2013 IN GENERAL...MAINLY DIURNAL CONVECTION ANTICIPATED WITH AS A SHORT WAVE CARVES OUT A DEEP UPPER TROUGH OVER THE GREAT LAKES THROUGH EARLY SATURDAY FOLLOWED WITH A TREND FOR DRIER AND COOLER AIR IN THE NORTH FLOW FOR THE REST OF THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK. DIURNAL CONVECTION TO BE ON THE DECREASE THURSDAY NIGHT IN THE WEAK CYCLONIC FLOW. WILL CONTINUE THE TREND OF MAINLY EVENING SHOWERS CHANCES FOR MOST LOCATIONS. OTHERWISE SHOWERS WITH ISOLATED STORMS TO BE ON THE INCREASE AGAIN FRIDAY AS THE COOLER UPPER TROUGH SLOWLY DRIFTS SOUTHWARD OVER THE GREAT LAKES REGION. AGAIN A DIURNAL DECREASE MAY OCCUR LATER FRIDAY EVENING...BUT SHOWER ACTIVITY NOT LIKELY TO END UNTIL THE TROUGH AXIS SHIFTS FAR ENOUGH SOUTH. THE ECMWF AND GFS WERE THE MOST PROGRESSIVE WITH THE TROUGH AND PCPN SOUTH OF THE AREA SATURDAY MORNING. THE NAM IS MUCH SLOWER WITH THE TROUGH PASSAGE AND HANGS ONTO PCPN THROUGH SATURDAY AFTERNOON. EVENTUALLY COOLER DRIER ON NORTHERLY WINDS WILL SWEEP SOUTH OVER THE WESTERN GREAT LAKES LATER SATURDAY THROUGH THE FIRST FEW DAYS OF THE NEXT WEEK AS THE CANADIAN SURFACE HIGH PRESSURE SETTLES IN. PCPN CHANCES BEGIN TO RETURN AFTER TUESDAY AS THE GFS PROG THIS DEEP TROUGH TO CUT OFF INTO AN UPPER LOW AND RETROGRADE BACK INTO WESTERN GREAT LAKES REGION. THE ECMWF HAS A SIMILAR SOLUTION BUT DROPS ANOTHER PIECE OF ENERGY INTO THE NORTHERN PLAINS IN THE NORTHWEST FLOW. RETURN FLOW TUESDAY INTO WEDNESDAY CONFINED TO THE ROCKIES AND NORTHERN PLAINS SO WILL KEEP POPS ON THE LOW SIDE. IN ADDITION...ANY CONVECTION WHICH CAN DEVELOP WILL LIKELY BE DIURNAL. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1045 PM CDT WED JUN 26 2013 SCATTERED SHOWERS AND THUNDERSTORMS SHOULD BECOME MORE ISOLATED OVERNIGHT INTO EARLY THURSDAY. LOCALLY HEAVY RAINFALL WILL STILL BE POSSIBLE OVER PARTS OF NC/NE WI. BREAKS IN THE CLOUDS AND LIGHT WINDS WILL ALLOW FOG TO DEVELOP OVERNIGHT...AND IT MAY BECOME DENSE IN LOCATIONS THAT RECEIVED SIGNIFICANT RAINFALL. WILL CARRY VLIFR CONDITIONS AT RHI. SHOWERS AND SCT TSTMS WILL INCREASE AGAIN BY MIDDAY THURSDAY...AS ANOTHER UPPER LEVEL DISTURBANCE MOVES THROUGH DURING PEAK AFTERNOON HEATING. STRONG/SEVERE TSTMS WILL BE POSSIBLE AGAIN THURSDAY AFTERNOON AND EARLY EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........KIECKBUSCH SHORT TERM.....MPC LONG TERM......TDH AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1010 PM CDT WED JUN 26 2013 .UPDATE... LOSS OF HEATING HAS CAUSED THE ISOLATED THUNDERSTORMS OVER CENTRAL AND SOUTHWEST WISCONSIN TO WEAKEN AND DIMINISH. HAD EXPECTED THIS TREND TO CONTINUE BUT THE SHOWERS HAVE INCREASED A LITTLE AGAIN. LATEST HRRR KEEPS A FAIRLY LARGE AREA OF SHOWERS AND THUNDERSTORMS THAT AFFECTS MUCH OF SOUTHEAST WISCONSIN LATE THIS EVENING. WILL INSTEAD GO SOMEWHAT BETWEEN THE 00Z NAM THAT KEEPS A MAINLY DRY FORECAST TONIGHT AND THE MORE AGRESSIVE HRRR. && .AVIATION/06Z TAFS/... MAINLY VFR CONDITIONS LATE THIS EVENING. THEN AREAS OF MVFR AND PATCHY IFR IN FOG. A FEW AREAS OF IFR CIGS ALSO POSSIBLE NEAR AND JUST AFTER SUNRISE. THEN AFTER SOME SCT CU AROUND 2-3 THSD FT THE CLOUDS HEIGHTS ARE EXPECTED TO RISE TO VFR. SCATTERED THUNDERSTORMS EXPECTED MAINLY DURING THE AFTERNOON THURSDAY. && .PREV DISCUSSION... /ISSUED 323 PM CDT WED JUN 26 2013/ THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE IS MEDIUM. A RATHER LARGE UPPER LEVEL TROF WILL DIG INTO THE GREAT LAKES AND EVOLVE INTO A CLOSED LOW FOR A TIME FRIDAY INTO FRIDAY NIGHT. THIS WILL ALLOW A FEW SHORT WAVES TO ROTATE SOUTH ACROSS THE AREA DURING THE PERIOD. COOLER AIR WILL FILTER IN AS WELL. THIS WILL RESULT IN CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THIS PERIOD. RAINFALL AMOUNTS WON/T BE IMPRESSIVE DUE TO THE WEAKER DEVELOPMENT AND FASTER MOVEMENT OF ANY ACTIVITY WE SEE. THE COMBO OF A DECENT SHORT WAVE AND AFTERNOON INSTABILITY WILL BRING THE BEST CHANCE FOR ANY RAIN FRIDAY AFTERNOON INTO THE EVENING. SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE IS MEDIUM. A DRIER AIRMASS ALONG WITH SURFACE HIGH PRESSURE SHOULD BRING US A NEEDED BREAK FROM THE RAINFALL DURING THIS PERIOD. HIGHS IN THE 70S WILL FEEL MUCH MORE COMFORTABLE. IT WILL BE COOLER AT TIMES NEAR LAKE MICHIGAN. AVIATION/00Z TAFS/... A WEAK COLD FRONT MOVING ACROSS WISCONSIN IS PRODUCING THUNDERSTORMS IN NORTHWEST WI. EXPECTING ANY CONVECTION ALONG THIS FRONT TO BE DIMINISHING AS IT REACHES SOUTH CENTRAL WI EARLY THIS EVENING. CLEARING BEHIND THE FRONT AND CALM/LIGHT WINDS WILL LEAD TO PATCHY FOG EARLY THURSDAY MORNING. THERE IS A POSSIBILITY FOR DENSE FOG TO DEVELOP IN SOUTHEAST WISCONSIN. AFTERNOON THUNDERSTORMS ARE POSSIBLE ON THURSDAY AS ANOTHER MID-LEVEL DISTURBANCE ROLLS THROUGH. MARINE... PATCHY FOG CONTINUES TO BE POSSIBLE IN THE NEARSHORE WATERS AS WARM AND HUMID AIR FLOWS OVER THE RELATIVELY COOL WATER. NORTHWEST WIND GUSTS COULD APPROACH SMALL CRAFT ADVISORY LEVELS FRIDAY AFTERNOON AS LOW PRESSURE PASSES THROUGH THE UPPER GREAT LAKES REGION. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...HENTZ TONIGHT/THURSDAY AND AVIATION/MARINE...MRC THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
932 PM CDT WED JUN 26 2013 .UPDATE... LOSS OF HEATING HAS CAUSED THE ISOLATED THUNDERSTORMS OVER CENTRAL AND SOUTHWEST WISCONSIN TO WEAKEN AND DIMINISH. EXPECT THIS TREND TO CONTINUE. LATEST HRRR DOES NOT TAKE THIS TREND AND KEEPS A FAIRLY LARGE AREA OF SHOWERS AND THUNDERSTORMS THAT AFFECTS MUCH OF SOUTHEAST WISCONSIN LATE THIS EVENING. WILL INSTEAD GO WITH THE LATEST RADAR TRENDS AND THE 00Z NAM THAT KEEPS A MAINLY DRY FORECAST TONIGHT. && .AVIATION/06Z TAFS/... MAINLY VFR CONDITIONS LATE THIS EVENING. THEN AREAS OF MVFR AND PATCHY IFR IN FOG. A FEW AREAS OF IFR CIGS ALSO POSSIBLE NEAR AND JUST AFTER SUNRISE. THEN AFTER SOME SCT CU AROUND 2-3 THSD FT THE CLOUDS HEIGHTS ARE EXPECTED TO RISE TO VFR. SCATTERED THUNDERSTORMS EXPECTED MAINLY DURING THE AFTERNOON THURSDAY. && .PREV DISCUSSION... /ISSUED 323 PM CDT WED JUN 26 2013/ THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE IS MEDIUM. A RATHER LARGE UPPER LEVEL TROF WILL DIG INTO THE GREAT LAKES AND EVOLVE INTO A CLOSED LOW FOR A TIME FRIDAY INTO FRIDAY NIGHT. THIS WILL ALLOW A FEW SHORT WAVES TO ROTATE SOUTH ACROSS THE AREA DURING THE PERIOD. COOLER AIR WILL FILTER IN AS WELL. THIS WILL RESULT IN CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THIS PERIOD. RAINFALL AMOUNTS WON/T BE IMPRESSIVE DUE TO THE WEAKER DEVELOPMENT AND FASTER MOVEMENT OF ANY ACTIVITY WE SEE. THE COMBO OF A DECENT SHORT WAVE AND AFTERNOON INSTABILITY WILL BRING THE BEST CHANCE FOR ANY RAIN FRIDAY AFTERNOON INTO THE EVENING. SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE IS MEDIUM. A DRIER AIRMASS ALONG WITH SURFACE HIGH PRESSURE SHOULD BRING US A NEEDED BREAK FROM THE RAINFALL DURING THIS PERIOD. HIGHS IN THE 70S WILL FEEL MUCH MORE COMFORTABLE. IT WILL BE COOLER AT TIMES NEAR LAKE MICHIGAN. AVIATION/00Z TAFS/... A WEAK COLD FRONT MOVING ACROSS WISCONSIN IS PRODUCING THUNDERSTORMS IN NORTHWEST WI. EXPECTING ANY CONVECTION ALONG THIS FRONT TO BE DIMINISHING AS IT REACHES SOUTH CENTRAL WI EARLY THIS EVENING. CLEARING BEHIND THE FRONT AND CALM/LIGHT WINDS WILL LEAD TO PATCHY FOG EARLY THURSDAY MORNING. THERE IS A POSSIBILITY FOR DENSE FOG TO DEVELOP IN SOUTHEAST WISCONSIN. AFTERNOON THUNDERSTORMS ARE POSSIBLE ON THURSDAY AS ANOTHER MID-LEVEL DISTURBANCE ROLLS THROUGH. MARINE... PATCHY FOG CONTINUES TO BE POSSIBLE IN THE NEARSHORE WATERS AS WARM AND HUMID AIR FLOWS OVER THE RELATIVELY COOL WATER. NORTHWEST WIND GUSTS COULD APPROACH SMALL CRAFT ADVISORY LEVELS FRIDAY AFTERNOON AS LOW PRESSURE PASSES THROUGH THE UPPER GREAT LAKES REGION. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...HENTZ TONIGHT/THURSDAY AND AVIATION/MARINE...MRC THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
904 PM CDT WED JUN 26 2013 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 847 PM CDT WED JUN 26 2013 WILL BE UPDATING PCPN TRENDS SHORTLY. ALTHOUGH CONVECTION HAS WEAKENED DUE TO DECREASING INSTABILITY...ADDITIONAL DEVELOPMENT WAS OCCURRING OVER NC WI...IN THE LFQ OF A 90-100 KT JET STREAK. ISOLATED CONVECTION WAS ALSO NOTED ACROSS FAR NORTHEAST ND AND NORTHERN MN...IN ASSOCIATION WITH A COUPLE S/W TROFS. CURRENT FCST HAS PCPN ENDING AFTER MIDNIGHT...BUT SUSPECT THAT AT LEAST ISOLD SHRA/TSRA WILL NEED TO BE KEPT IN THE FCST OVERNIGHT. PARTLY CLOUDY SKIES AND LIGHT WINDS WILL LEAD TO ANOTHER ROUND OF FOG OVERNIGHT. THE THICKEST FOG SHOULD OCCUR OVER NC/NE WI... WHERE THE MOST SIGNIFICANT RAINFALL OCCURRED THIS AFTERNOON AND EVENING. && .SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 225 PM CDT WED JUN 26 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ELONGATED SHORTWAVE TROUGH SPINNING OVER THE LAKE WINNIPEG REGION WHICH ALSO EXTENDS SOUTH INTO THE NORTHERN MISSISSIPPI VALLEY. ANOTHER SHORTWAVE IS SPINNING OVER NORTHERN ILLINOIS AND IS HEADING EAST...SO NOT MUCH IMPACT ACROSS OUR AREA. STORMS FIRED UP AROUND MIDDAY ALONG A SURFACE TROUGH OVER THE WI/MN BORDER WHERE ML CAPES ARE REACHING UP TO 2K J/KG. THE FIRST WARNING THIS AFTERNOON WAS JUST ISSUED A FEW MINUTES AGO...BUT STORMS ARE NOT SHOWING MUCH ORGANIZATION AND 0-6KM BULK SHEAR VALUES ARE RATHER POOR AT AROUND 20 KTS. WITH SUCH WEAK BULK SHEAR VALUES...THINKING PULSY SEVERE AT THIS TIME UNLESS STORMS CAN BECOME MORE ORGANIZED. A FEW SPOTTY SHOWERS TRIED TO DEVELOP OVER NORTH-CENTRAL AND FAR NORTHEAST WISCONSIN...BUT FIZZLED OUT. SEVERE WEATHER CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LATEST TIMING HAS STORMS ARRIVING INTO NORTH-CENTRAL WISCONSIN AT AROUND 21Z AND PROGRESSING EAST TO NORTHEAST WISCONSIN BY 00-01Z BEFORE EXITING AFTER 04Z. WITH STORMS ARRIVING AT OR NEAR PEAK HEATING...SEVERE WEATHER HAS POTENTIAL TO REACH NORTHEAST WISCONSIN THOUGH CAPES ARE NOT NEARLY AS IMPRESSIVE OVER NORTHEAST AND EAST-CENTRAL WISCONSIN AS FURTHER WEST. WITH LOSS OF HEATING AND WEAKER INSTABILITY...THINK SEVERE THREAT OVER THE EASTERN PARTS OF THE STATE ARE VERY MARGINAL. BETTER CHANCES WILL BE OVER NORTH-CENTRAL WISCONSIN. ONCE THE STORMS DEPARTS/WEAKEN...RATHER JUICY AIRMASS WILL LINGER FOR THE REST OF THE NIGHT. AREAS THAT RECEIVED RAIN WILL BE PRIME CANDIDATES FOR DENSE FOG AND WILL ADD FOG TO THE FORECAST. LOWS MAINLY IN THE LOW TO MID 60S. THURSDAY...THE UPPER TROUGH OVER LAKE WINNIPEG WILL SLIDE SOUTHEAST INTO LAKE SUPERIOR. WILL HAVE SUPPORT IN THE FORM OF UPPER DIVERGENCE IN THE LEFT FRONT QUAD OF THE JET STREAK FOR MUCH OF THE DAY...SO CANNOT RULE OUT SPOTTY SHOWERS AND STORMS IN THE MORNING. BUT THINKING STORMS ARE LIKELY FOR MOST OF NORTH-CENTRAL AND NORTHEAST WISCONSIN IN THE AFTERNOON...ONCE UPWARDS OF 1500 J/KG OF ML CAPE CAN DEVELOP ACCORDING TO PROGGED SOUNDINGS. WITH DEEP MIXING AND 0-6KM BULK SHEAR AROUND 30KTS...THINK SEVERE WEATHER IS POSSIBLE TOMORROW AFTERNOON. DAMAGING WIND GUSTS AND LARGE HAIL WILL BE THE MAIN THREATS. SHOULD FEEL LESS HUMID OUT THERE THAN TODAY...BUT HIGHS SHOULD STILL REACH INTO THE LOW TO MID 80S. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 225 PM CDT WED JUN 26 2013 IN GENERAL...MAINLY DIURNAL CONVECTION ANTICIPATED WITH AS A SHORT WAVE CARVES OUT A DEEP UPPER TROUGH OVER THE GREAT LAKES THROUGH EARLY SATURDAY FOLLOWED WITH A TREND FOR DRIER AND COOLER AIR IN THE NORTH FLOW FOR THE REST OF THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK. DIURNAL CONVECTION TO BE ON THE DECREASE THURSDAY NIGHT IN THE WEAK CYCLONIC FLOW. WILL CONTINUE THE TREND OF MAINLY EVENING SHOWERS CHANCES FOR MOST LOCATIONS. OTHERWISE SHOWERS WITH ISOLATED STORMS TO BE ON THE INCREASE AGAIN FRIDAY AS THE COOLER UPPER TROUGH SLOWLY DRIFTS SOUTHWARD OVER THE GREAT LAKES REGION. AGAIN A DIURNAL DECREASE MAY OCCUR LATER FRIDAY EVENING...BUT SHOWER ACTIVITY NOT LIKELY TO END UNTIL THE TROUGH AXIS SHIFTS FAR ENOUGH SOUTH. THE ECMWF AND GFS WERE THE MOST PROGRESSIVE WITH THE TROUGH AND PCPN SOUTH OF THE AREA SATURDAY MORNING. THE NAM IS MUCH SLOWER WITH THE TROUGH PASSAGE AND HANGS ONTO PCPN THROUGH SATURDAY AFTERNOON. EVENTUALLY COOLER DRIER ON NORTHERLY WINDS WILL SWEEP SOUTH OVER THE WESTERN GREAT LAKES LATER SATURDAY THROUGH THE FIRST FEW DAYS OF THE NEXT WEEK AS THE CANADIAN SURFACE HIGH PRESSURE SETTLES IN. PCPN CHANCES BEGIN TO RETURN AFTER TUESDAY AS THE GFS PROG THIS DEEP TROUGH TO CUT OFF INTO AN UPPER LOW AND RETROGRADE BACK INTO WESTERN GREAT LAKES REGION. THE ECMWF HAS A SIMILAR SOLUTION BUT DROPS ANOTHER PIECE OF ENERGY INTO THE NORTHERN PLAINS IN THE NORTHWEST FLOW. RETURN FLOW TUESDAY INTO WEDNESDAY CONFINED TO THE ROCKIES AND NORTHERN PLAINS SO WILL KEEP POPS ON THE LOW SIDE. IN ADDITION...ANY CONVECTION WHICH CAN DEVELOP WILL LIKELY BE DIURNAL. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 637 PM CDT WED JUN 26 2013 SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL...HAIL AND GUSTY WINDS HAVE MOVED THROUGH NC/FAR NE/C WI LATE THIS AFTERNOON... BUT HAVE GRADUALLY WEAKENED IN INTENSITY OVER THE PAST HOUR. THE STORMS WILL IMPACT RHI/AUW/CWA THROUGH 01Z...BUT THEY MAY DISSIPATE BEFORE REACHING ATW/GRB. WILL LEAVE OUT THE MENTION OF TSTMS FOR ATW/GRB FOR THIS EVG...AND ADD THEM IN IF IT BECOMES APPARENT THAT WILL IMPACT THE AREA. PARTLY CLOUDY SKIES AND LIGHT WINDS WILL ALLOW FOG TO REDEVELOP AGAIN TONIGHT...AND IT MAY BECOME DENSE IN LOCATIONS THAT RECEIVED SIGNIFICANT RAINFALL. WILL CARRY VLIFR CONDITIONS AT RHI...AND MAY NEED TO ADD INTO CWA/AUW LATER. SHOWERS AND SCT TSTMS WILL INCREASE AGAIN BY MIDDAY THURSDAY...AS ANOTHER UPPER LEVEL DISTURBANCE MOVES THROUGH DURING PEAK AFTERNOON HEATING. STRONG/SEVERE TSTMS WILL BE POSSIBLE AGAIN THURSDAY AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........KIECKBUSCH SHORT TERM.....MPC LONG TERM......TDH AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
645 PM CDT WED JUN 26 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 225 PM CDT WED JUN 26 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ELONGATED SHORTWAVE TROUGH SPINNING OVER THE LAKE WINNIPEG REGION WHICH ALSO EXTENDS SOUTH INTO THE NORTHERN MISSISSIPPI VALLEY. ANOTHER SHORTWAVE IS SPINNING OVER NORTHERN ILLINOIS AND IS HEADING EAST...SO NOT MUCH IMPACT ACROSS OUR AREA. STORMS FIRED UP AROUND MIDDAY ALONG A SURFACE TROUGH OVER THE WI/MN BORDER WHERE ML CAPES ARE REACHING UP TO 2K J/KG. THE FIRST WARNING THIS AFTERNOON WAS JUST ISSUED A FEW MINUTES AGO...BUT STORMS ARE NOT SHOWING MUCH ORGANIZATION AND 0-6KM BULK SHEAR VALUES ARE RATHER POOR AT AROUND 20 KTS. WITH SUCH WEAK BULK SHEAR VALUES...THINKING PULSY SEVERE AT THIS TIME UNLESS STORMS CAN BECOME MORE ORGANIZED. A FEW SPOTTY SHOWERS TRIED TO DEVELOP OVER NORTH-CENTRAL AND FAR NORTHEAST WISCONSIN...BUT FIZZLED OUT. SEVERE WEATHER CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LATEST TIMING HAS STORMS ARRIVING INTO NORTH-CENTRAL WISCONSIN AT AROUND 21Z AND PROGRESSING EAST TO NORTHEAST WISCONSIN BY 00-01Z BEFORE EXITING AFTER 04Z. WITH STORMS ARRIVING AT OR NEAR PEAK HEATING...SEVERE WEATHER HAS POTENTIAL TO REACH NORTHEAST WISCONSIN THOUGH CAPES ARE NOT NEARLY AS IMPRESSIVE OVER NORTHEAST AND EAST-CENTRAL WISCONSIN AS FURTHER WEST. WITH LOSS OF HEATING AND WEAKER INSTABILITY...THINK SEVERE THREAT OVER THE EASTERN PARTS OF THE STATE ARE VERY MARGINAL. BETTER CHANCES WILL BE OVER NORTH-CENTRAL WISCONSIN. ONCE THE STORMS DEPARTS/WEAKEN...RATHER JUICY AIRMASS WILL LINGER FOR THE REST OF THE NIGHT. AREAS THAT RECEIVED RAIN WILL BE PRIME CANDIDATES FOR DENSE FOG AND WILL ADD FOG TO THE FORECAST. LOWS MAINLY IN THE LOW TO MID 60S. THURSDAY...THE UPPER TROUGH OVER LAKE WINNIPEG WILL SLIDE SOUTHEAST INTO LAKE SUPERIOR. WILL HAVE SUPPORT IN THE FORM OF UPPER DIVERGENCE IN THE LEFT FRONT QUAD OF THE JET STREAK FOR MUCH OF THE DAY...SO CANNOT RULE OUT SPOTTY SHOWERS AND STORMS IN THE MORNING. BUT THINKING STORMS ARE LIKELY FOR MOST OF NORTH-CENTRAL AND NORTHEAST WISCONSIN IN THE AFTERNOON...ONCE UPWARDS OF 1500 J/KG OF ML CAPE CAN DEVELOP ACCORDING TO PROGGED SOUNDINGS. WITH DEEP MIXING AND 0-6KM BULK SHEAR AROUND 30KTS...THINK SEVERE WEATHER IS POSSIBLE TOMORROW AFTERNOON. DAMAGING WIND GUSTS AND LARGE HAIL WILL BE THE MAIN THREATS. SHOULD FEEL LESS HUMID OUT THERE THAN TODAY...BUT HIGHS SHOULD STILL REACH INTO THE LOW TO MID 80S. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 225 PM CDT WED JUN 26 2013 IN GENERAL...MAINLY DIURNAL CONVECTION ANTICIPATED WITH AS A SHORT WAVE CARVES OUT A DEEP UPPER TROUGH OVER THE GREAT LAKES THROUGH EARLY SATURDAY FOLLOWED WITH A TREND FOR DRIER AND COOLER AIR IN THE NORTH FLOW FOR THE REST OF THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK. DIURNAL CONVECTION TO BE ON THE DECREASE THURSDAY NIGHT IN THE WEAK CYCLONIC FLOW. WILL CONTINUE THE TREND OF MAINLY EVENING SHOWERS CHANCES FOR MOST LOCATIONS. OTHERWISE SHOWERS WITH ISOLATED STORMS TO BE ON THE INCREASE AGAIN FRIDAY AS THE COOLER UPPER TROUGH SLOWLY DRIFTS SOUTHWARD OVER THE GREAT LAKES REGION. AGAIN A DIURNAL DECREASE MAY OCCUR LATER FRIDAY EVENING...BUT SHOWER ACTIVITY NOT LIKELY TO END UNTIL THE TROUGH AXIS SHIFTS FAR ENOUGH SOUTH. THE ECMWF AND GFS WERE THE MOST PROGRESSIVE WITH THE TROUGH AND PCPN SOUTH OF THE AREA SATURDAY MORNING. THE NAM IS MUCH SLOWER WITH THE TROUGH PASSAGE AND HANGS ONTO PCPN THROUGH SATURDAY AFTERNOON. EVENTUALLY COOLER DRIER ON NORTHERLY WINDS WILL SWEEP SOUTH OVER THE WESTERN GREAT LAKES LATER SATURDAY THROUGH THE FIRST FEW DAYS OF THE NEXT WEEK AS THE CANADIAN SURFACE HIGH PRESSURE SETTLES IN. PCPN CHANCES BEGIN TO RETURN AFTER TUESDAY AS THE GFS PROG THIS DEEP TROUGH TO CUT OFF INTO AN UPPER LOW AND RETROGRADE BACK INTO WESTERN GREAT LAKES REGION. THE ECMWF HAS A SIMILAR SOLUTION BUT DROPS ANOTHER PIECE OF ENERGY INTO THE NORTHERN PLAINS IN THE NORTHWEST FLOW. RETURN FLOW TUESDAY INTO WEDNESDAY CONFINED TO THE ROCKIES AND NORTHERN PLAINS SO WILL KEEP POPS ON THE LOW SIDE. IN ADDITION...ANY CONVECTION WHICH CAN DEVELOP WILL LIKELY BE DIURNAL. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 637 PM CDT WED JUN 26 2013 SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL...HAIL AND GUSTY WINDS HAVE MOVED THROUGH NC/FAR NE/C WI LATE THIS AFTERNOON... BUT HAVE GRADUALLY WEAKENED IN INTENSITY OVER THE PAST HOUR. THE STORMS WILL IMPACT RHI/AUW/CWA THROUGH 01Z...BUT THEY MAY DISSIPATE BEFORE REACHING ATW/GRB. WILL LEAVE OUT THE MENTION OF TSTMS FOR ATW/GRB FOR THIS EVG...AND ADD THEM IN IF IT BECOMES APPARENT THAT WILL IMPACT THE AREA. PARTLY CLOUDY SKIES AND LIGHT WINDS WILL ALLOW FOG TO REDEVELOP AGAIN TONIGHT...AND IT MAY BECOME DENSE IN LOCATIONS THAT RECEIVED SIGNIFICANT RAINFALL. WILL CARRY VLIFR CONDITIONS AT RHI...AND MAY NEED TO ADD INTO CWA/AUW LATER. SHOWERS AND SCT TSTMS WILL INCREASE AGAIN BY MIDDAY THURSDAY...AS ANOTHER UPPER LEVEL DISTURBANCE MOVES THROUGH DURING PEAK AFTERNOON HEATING. STRONG/SEVERE TSTMS WILL BE POSSIBLE AGAIN THURSDAY AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TDH AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
632 PM CDT WED JUN 26 2013 .SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT) ISSUED AT 231 PM CDT WED JUN 26 2013 SURFACE MAP THIS AFTERNOON HAS A COLD FRONT MOVING EAST ACROSS EASTERN MN/IA. RADAR SHOWING A BROKEN LINE OF THUNDERSTORMS //SOME FAIRLY INTENSE TO SEVERE AT TIMES// EXTENDING N-S ALONG THIS FRONTAL BOUNDARY. LITTLE 0-3KM BULK SHEAR NOTED SO MOST OF THESE STORMS ARE PULSE-TYPE IN NATURE WITH HIGHER-END RAP 0-1KM ML MUCAPE IN THE 3500-4200J/KG RANGE. THIS UNSTABLE AIR IS BEING PRODUCED BY TEMPERATURES ACROSS THE AREA IN THE 80-85 DEGREE RANGE AND DEW POINTS IN THE LOWER 70S. LOOK FOR THIS FRONT TO SLIP EAST INTO CENTRAL WI THIS EVENING... DRAGGING THE BULK OF THE SHOWERS/THUNDERSTORMS WITH IT. WITH PRECIPITABLE WATER VALUES STILL SITTING IN THE 1.5-1.8 INCH RANGE...ANY SHOWER/THUNDERSTORM EARLY THIS EVENING WILL BE CAPABLE OF TORRENTIAL DOWNPOURS WITH SOME LOCALIZED PONDING OF WATER POSSIBLE...ESPECIALLY ACROSS AREAS THAT RECEIVED PREVIOUS HEAVY RAIN AND HAVE ALREADY SATURATED SOILS. INTRODUCED A SLIGHT CHANCE OF SHOWER/THUNDERSTORMS MAINLY NORTH OF I-94 LATER OVERNIGHT//AFTER 09Z// AS A MID-LEVEL TROUGH AND LEFT EXIT REGION OF 75-100KT 300MB JET PUSHES INTO THIS AREA. MOST OF THIS ACTIVITY LOOKS ELEVATED/ACCAS TYPE IN NATURE. BUFKIT SHOWS DRYING IN THE LOWER LEVELS...SO NOT CONFIDENT ON HOW MUCH RAINFALL WILL ACTUALLY REACH THE SURFACE. THEREFORE...WILL KEEP POPS ON THE LOW SIDE FOR NOW. THIS MID-LEVEL WAVE CONTINUES TO MOVE ACROSS THE AREA ON THURSDAY FOR A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER. MAY HAVE TO WATCH THIS CONVECTION CLOSELY FOR SEVERE WIND/HAIL THREAT GIVEN STEEPER LAPSE RATES AND 0-6KM BULK SHEAR IN THE 35-45KT RANGE. THE GFS... WHICH IS THE DRIEST OF THE MODELS AS FAR AS DEWPOINTS...YIELDS 0-1KM MLCAPE IN THE 1000-1500J/KG RANGE. IN ADDITION...MAY HAVE SOME ADDED LIFT DUE TO THE LEFT EXIT REGION OF 75-100KT 300MB JET. OTHERWISE...LOOKING FOR A HIGH IN THE LOWER/MIDDLE 80S WITH DEW POINTS IN THE MIDDLE 60S. LOOK FOR THE MID-LEVEL WAVE TO EXIT EAST OF THE REGION BY LATE THURSDAY EVENING...END THE THUNDERSTORM THREAT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 231 PM CDT WED JUN 26 2013 ON FRIDAY...MODELS IN GOOD AGREEMENT IN SWINGING A MID-LEVEL TROUGH SOUTHWESTWARD INTO THE AREA FROM THE GREAT LAKES REGION. STEEPENING LAPSE RATES WITH ASSOCIATED COLDER CYCLONIC FLOW ALOFT EXPECTED TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS MAINLY EAST OF THE MISSISSIPPI RIVER. OTHERWISE...PLAN ON HIGHS COOLING SOMEWHAT INTO THE MID 70S TO AROUND 80 WITH FAIRLY BREEZY NORTHWEST WINDS IN THE 10-20 MPH RANGE. LOOK FOR COOLER CONDITIONS WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORM ACTIVITY TO CONTINUE FRIDAY NIGHT THROUGH SATURDAY AS THE MID-LEVEL TROUGH SWINGS SOUTH THROUGH THE AREA. HIGHS ON SATURDAY WILL ACTUALLY SLIP SLIGHTLY BELOW NORMAL LEVELS IN THE LOW-MID 70S. APPEARS SHOWERS WILL BE EXITING THE AREA COMPLETELY BY SATURDAY EVENING AS THE TROUGH SHIFTS SOUTHEAST TOWARD THE OHIO RIVER VALLEY AND RIDGING BUILDS IN FROM THE NORTHWEST. FOR SUNDAY THROUGH WEDNESDAY...PLAN ON COOLER/OVERALL DRIER CONDITIONS AS A MAJOR MID-LEVEL TROUGH ESTABLISHES ITSELF OVER THE CENTRAL CONUS WITH A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS. EC REMAINS DRY DESPITE COOLER CYCLONIC FLOW AND THE GFS IS LIGHT AND SPOTTY WITH ITS QPF. LOOKS LIKE MAINLY SOME DAYTIME CUMULUS BUT REMAINING DRY. OTHERWISE...HIGHS ARE EXPECTED TO BE IN THE 75-80 DEGREE RANGE WITH OVERNIGHT LOWS MAINLY IN THE 50S...VERY PLEASANT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 632 PM CDT WED JUN 26 2013 AS OF 00Z THURSDAY...SURFACE FRONT CROSSING MISSISSIPPI RIVER...AND WILL LIKELY REACH CENTRAL WISCONSIN BY EARLY EVENING. SHOWERS AND THUNDERSTORM THREATS END AS IT PASSES AND VFR CONDITIONS WILL PREVAIL IN ITS WAKE. DURING THE OVERNIGHT...AS THE BOUNDARY LAYER DECOUPLES THERE COULD BE MVFR FOG/MIST AT KLSE BUT WINDS LOOK TO BE HIGH ENOUGH TO KEEP LOW-LEVELS MIXED SUFFICIENTLY. FOR THURSDAY...NORTHWEST WINDS WILL PERSIST AND PLAN ON AFTERNOON GUSTS ALONG WITH A SCATTERED VFR CUMULUS FIELD. THE GREATER SHOWER AND THUNDERSTORM CHANCES THURSDAY AFTERNOON WILL BE EAST OF KLSE...MORE ACROSS CENTRAL WISCONSIN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...ZT
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
339 PM CDT TUE JUN 25 2013 .VERY SHORT TERM...TONIGHT AND WEDNESDAY. TONIGHT - CONFIDENCE...LOW MAIN CHALLENGE CENTERS ON CONVECTIVE TRENDS AS HAS BEEN THE CASE THE LAST SEVERAL DAYS. AIR MASS DESTABILIZATION UNDERWAY WITH -11 LI/S INTO SW CWA. CORRIDOR OF HIGH ML CAPE VALUES ALSO LOCATED THERE AS WELL...WITH VALUES AS HIGH AS 3500 J/KG. SPC MONITORING FOR A WATCH WITH BORDERLINE 30-35 KNOT 0-6 KM BULK SHEAR. WATER VAPOR/RUC SHOWING A WEAK RIPPLE ACROSS SRN MN/NRN IA...MAY BE ENOUGH TO ENHANCE THE ALREADY DEVELOPING CONVECTION NEAR KDBQ. AIR MASS IS BECOMING INCREASINGLY MOIST AND UNSTABLE. 3 HOUR ML CAPE CHANGE AROUND 1500 J/KG INTO THE SW CWA. DEEP LAYER MOISTURE FLUX CONVERGENCE ALSO MAXIMIZED IN A CORRIDOR FROM NRN IL INTO SW WI. SUPERCELL COMPOSITE MAXIMIZED SOUTH OF MADISON...THOUGH DRIVEN LARGELY BY THE VERY HIGH CAPE VALUES. LATEST HRRR BLOWS UP THIS AREA IN SW WI AND SPREADS IT ACROSS CWA THROUGH 01Z. LATER IN THE NIGHT LOW LEVEL JET NOSE DISPLACED FURTHER SOUTH AND EAST AND HRRR BLOSSOMS THINGS ACROSS IOWA AND THIS WOULD THEN HEAD SOUTHEAST...POSSIBLY GRAZING FAR SRN WI. SURFACE FLOW IS ADVECTING 70 PLUS DEW POINT AIR INTO SRN WI. MODELS IN DECENT AGREEMENT IN BRINGING A VORT MAX INTO IOWA AND TO JUST SOUTH OF WI BY 12Z. VORTICITY ADVECTION WITH THIS FEATURE BRINGS BEST FORCING TO SW CWA AROUND 6Z AND SPREADS IT ACROSS THE REST OF THE AREA BETWEEN 6-12Z. AT THIS POINT TEND TO SIDE WITH THE MODELS SHOWING TSRA AFFECTING THE CWA TONIGHT...ESPECIALLY THE SW 1/2...WITHIN AND NEAR THE LI/CAPE GRADIENTS IN CONJUNCTION WITH THE APPROACHING UPPER FEATURE. THE NAM AND SOME OF THE OTHER MESO MODELS SHOW NEXT TO NOTHING WHICH IS A CONCERN IF THE 850 LEANS FURTHER SOUTH. FOR NOW WILL RETAIN THE HEFTY POPS WE HAVE GOING AND HANG ONTO THE FLASH FLOOD WATCH. WEDNESDAY - CONFIDENCE...MEDIUM INFLUENCE OF THE 500 MILLIBAR WAVE SHIFTS EAST BY THE AFTERNOON AND PER SWODY1 THE REAL FOCUS FOR THE HEFTY ACTIVITY SHIFTS INTO OH VALLEY. PROGS SHOW BEST QPF IN THE MORNING WITH BETTER CWASP NUMBERS INTO THE OHIO VALLEY. HOWEVER STILL SOME LINGERING TROUGHINESS SO WILL KEEP POPS GOING INTO THE AFTERNOON. BUT ALL IN ALL THE 850 JET INFLUENCE AND UPPER FORCING SHIFTS TO OUR SOUTH AND EAST EARLY IN THE DAY. .SHORT TERM...WEDNESDAY NIGHT THROUGH FRIDAY. WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM. SHORT WAVE TROUGH MOVES OFF TO THE EAST WITH BETTER FORCING STAYING MORE CLOSELY TIED TO THE VORT MAX/PV ANOMALY PASSING NE OF FORECAST AREA WEDNESDAY NIGHT...WELL REFLECTED IN LAYER Q-VECTOR CONVERGENCE AND ISENTROPIC OMEGA. HOWEVER LOW-LEVEL MOISTURE CONVERGENCE MOVES ACROSS CWA WITH WEAK SURFACE TROUGH WITH LINGERING INSTABILITY IN THE EVENING TO KEEP A CHANCE OF THUNDERSTORMS...TAPERING TO A SLIGHT CHANCE OVERNIGHT. HAVE CHANCE POPS THURSDAY AFTERNOON AS ANOTHER VORT MAX DROPS SE THROUGH THE STATE...WITH SLIGHTLY STEEPENING MID-LEVEL LAPSE RATES LEADING TO PEAK HEAT OF THE DAY INSTABILITY. THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE LOW TO MEDIUM. 300 MB SPEED MAX BRINGS A SHORT WAVE TROUGH OF VARYING STRENGTH DEPENDING ON MODEL INTO THE REGION WITH DCVA-DRIVEN PCPN REACHING THE NORTH THURSDAY NIGHT WITH THE BETTER CHANCE ACROSS THE REST OF THE CWA FRIDAY. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. FORECAST CONFIDENCE LOW. UNSETTLED PERIOD WITH UPPER TROUGH NOW RETROGRADING FARTHER WEST THAN PREVIOUS DAYS AND SETTLING OVER THE WESTERN GREAT LAKES THROUGH THE REMAINDER OF THE PERIOD. GFS HAS A DRIER LOOK THAN ECMWF AS IT DIGS AN OPEN WAVE WHILE ECMWF KEEPS A CLOSED LOW RIGHT OVER THE STATE. WE MAY BE GETTING RID OF THE HEAVY RAINS/SEVERE WITH THE EXIT OF THE MOIST AIR MASS...BUT ENOUGH INSTABILITY AND WEAK FORCING WITH VORT MAXES MOVING THROUGH THE TROUGH TO KEEP AT LEAST SLIGHT CHANCES IN FOR MUCH OF THE EXTENDED...THOUGH BLENDED GUIDANCE BRINGS LESSER CHANCES IN FOR EARLY NEXT WEEK. AT OR BELOW NORMAL TEMPERATURES ARE EXPECTED. && .AVIATION/00Z TAFS/...AS HAS BEEN THE CASE THE LAST COUPLE OF DAYS CEILINGS/VSBYS WILL BE DRIVEN BY CONVECTIVE EVENTS. EXPECTING ADDITIONAL DEVELOPMENT AS THE NIGHT WEARS ALONG. 500 MILLIBAR SHORTWAVE APPROACHES AND INTERACTS WITH INCREASINGLY UNSTABLE AIRMASS. INFLUENCE OF THIS SHORTWAVE WILL CONTINUE INTO WEDNESDAY MORNING...BEFORE BEST FORCING SHIFTS INTO THE OHIO VALLEY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR WIZ046-047-056- 057-062-063-067>070. LM...NONE. && $$ TONIGHT/WEDNESDAY AND AVIATION/MARINE...COLLAR WEDNESDAY NIGHT THROUGH TUESDAY...REM
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 255 PM CDT TUE JUN 25 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW EARLIER CONVECTION ACROSS IOWA AND SOUTHERN WISCONSIN DISSIPATED/EXITED EARLIER THIS AFTERNOON. TOUGH TO TELL WHERE THE OUTFLOW BOUNDARY STALLED OUT...BUT AN ARCING LINE OF CLOUDS FROM NW IOWA TO MOLINE TO NW OHIO COULD BE IT. REMNANT SHORTWAVE MOVING ACROSS SOUTHERN MINNESOTA AND IOWA IS RELATIVE INACTIVE SO FAR THIS AFTERNOON...AS IS MUCH OF THE STATE OF WISCONSIN. A FEW STORMS POPPED UP OVER SOUTHERN WISCONSIN AND ALSO WILL NEED TO WATCH THE AREA OF CU OVER NORTHERN WISCONSIN FOR SHOWER/TSTORM DEVELOP LATER THIS AFTERNOON. ML CAPES ARE BUILDING TO AROUND 800 J/KG BUT NEED A LITTLE MORE LIFT VIA LAKE BREEZES TO GET CONVECTION STARTED. AN AREA OVER FAR NORTHERN WISCONSIN MIXED OUT...SO WILL SHIFT PRECIP CHANCES MAINLY SOUTH OF VILAS COUNTY. THE NEXT AREA OF WEATHER IS MOVING ACROSS THE PLAINS WHICH WILL ARRIVE TOMORROW. PRECIP CHANCES CONTINUE TO BE THE MAIN FORECAST CONCERNS. TONIGHT...WILL KEEP AN ISOLATED MENTIONED OF THUNDERSTORMS OVER CENTRAL WISCONSIN AS WELL AS NORTHERN WISCONSIN UNTIL DIURNAL INSTABILITY DIMINISHES. BY MID TO LATE EVENING...A LLJ WILL GET CRANKING OVER THE CENTRAL PLAINS AHEAD OF THE NEXT LOW PRESSURE SYSTEM. THE NAM/GFS/ECMWF ALL SUGGEST THAT THE NOSE OF THE LLJ WILL POINT TOWARDS NORTHERN IOWA/SOUTHERN WISCONSIN/NORTHERN ILLINOIS...WHICH IS THE REGION THAT HAS BEEN LIGHTING UP WITH STORMS EACH OF THE PAST SEVERAL NIGHTS. DO NOT HAVE ANY REASON TO THINK DIFFERENTLY THIS TIME...BUT DO HAVE WEAK ISENTROPIC ASCENT OCCURRING OVER CENTRAL WISCONSIN THIS EVENING...THAT MOVES INTO NORTH-CENTRAL AND EAST-CENTRAL WISCONSIN OVERNIGHT. WILL KEEP A SMALL CHANCE OF STORMS OVERNIGHT. ANY SEVERE THREAT LOOKS TO REMAIN TO THE SOUTH HOWEVER. ANOTHER MUGGY NIGHT WITH LOWS IN THE 60S. WEDNESDAY...LOW PRESSURE OVER THE NORTHERN MISSISSIPPI VALLEY AT THE START OF THE PERIOD WILL SHIFT SLOWLY EAST INTO WISCONSIN. MODELS HAVE SLOWED DOWN THE PROGRESSION OF THIS LOW SOMEWHAT...SO WILL DELAY THE LIKELY POPS UNTIL THE AFTERNOON. EVEN WITH THE SLOWER ARRIVAL...AM ANTICIPATING PLENTY OF CLOUD COVER WHICH SHOULD REDUCE SURFACE HEATING AND INSTABILITY. A SEVERE THREAT SEEMS TO LOW TO MENTION AT THIS TIME THOUGH ANY STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 255 PM CDT TUE JUN 25 2013 WHILE THE UPPER LEVEL WINDS ARE EXPECTED TO BECOME NORTHWEST THURSDAY WHILE THE UPPER RIDGE BUILDS OVER THE WESTERN STATES...IT WILL TAKE A WHILE BEFORE WE GET THE DRY WEATHER USUALLY ASSOCIATED WITH NORTHWEST UPPER FLOW. THE REASON IS THAT SEVERAL JET STREAKS ARE FORECAST TO ROTATE AROUND THE UPPER RIDGE AND DIVE INTO THE GREAT LAKES TROUGH. THIS RESULTS IN THE FORMATION OF AN ELONGATED UPPER TROUGH OR LOW OVER THE GREAT LAKES. SEVERAL UPPER JETS SHOULD PROVIDE UPPER SUPPORT FOR PRECIPITATION AT TIMES WHILE THERE IS RESIDUAL LOW LEVEL MOISTURE. SUNDAY AND MONDAY LOOK TO BE THE DAYS WITH THE LEAST CHANCE OF RAIN ALONG WITH COOL TEMPERATURES AND LOW DEW POINTS. LOOKS LIKE A WEAK UPPER LEVEL LOW CONTINUES ACROSS THE AREA THROUGH THE MIDDLE OF NEXT WEEK THOUGH THERE IS SOME INDICATION THAT IT WILL BEGIN TO EXIT ON INDEPENDENCE DAY. NOT MUCH CONFIDENCE IN THE UPPER PATTERN THOUGH. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1240 PM CDT TUE JUN 25 2013 SHOWERS AND THUNDERSTORMS OVER IOWA AND SOUTHERN WISCONSIN HAS PUSHED A RAIN COOLED BOUNDARY WELL SOUTH OF THE REGION. MEANWHILE...A LAKE SUPERIOR ENHANCED COLD FRONT WILL SETTLE ACROSS NORTHERN WISCONSIN THIS AFTERNOON. THIS COLD FRONT MAY GENERATE SCT SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON BEFORE DIMINISHING EARLY THIS EVENING. COVERAGE IS UNCERTAIN SO WILL LEAVE OUT OF THE RHI TAF. THEN THE BOUNDARY OVER IOWA AND NORTHERN ILLINOIS WILL RETURN NORTH TONIGHT AHEAD OF A LOW PRESSURE SYSTEM. SHOWERS AND SCT THUNDERSTORMS ARE ANTICIPATED AHEAD OF THIS LOW PRESSURE SYSTEM TOMORROW. TIMING STILL UNCERTAIN AS VARIOUS 12Z MODELS HAVE PUSHED PRECIP BACK UNTIL THE AFTERNOON. WILL DELAY THE PRECIP UNTIL THE MORNING...BUT FUTURE TIMING CHANGES WILL LIKELY BE NEEDED. CONDITIONS TO FALL TO MVFR WITHIN SHOWERS AND TSTORMS. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1222 AM CDT TUE JUN 25 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 304 PM CDT MON JUN 24 2013 AT 3 PM...A SQUALL LINE WAS MOVING EAST THROUGH EAST-CENTRAL AND SOUTHEAST IOWA. THIS LINE HAS WIPED OUT MUCH OF THE INSTABILITY THAT MANY OF 24.00Z AND 24.06Z MODELS WERE FORECASTING TO MOVE INTO NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND SOUTHWEST AND CENTRAL WISCONSIN TONIGHT. EVEN SOME OF THE 24.12Z DETERMINISTIC MODELS WERE NOT HANDLING THIS LINE WELL...SO THEY ARE TOO HIGH ON THEIR CAPES ACROSS IOWA. IN ADDITION...THIS LINE ALSO DISRUPTED THE 925 MB AND 850 MB MOISTURE TRANSPORT INTO THE REGION. AS A RESULT...THE HEAVY RAIN THREAT FOR THIS EVENING LOOKS MUCH LESS THAN WHAT IT WAS LOOKING LIKE EARLIER THIS MORNING. FOR OVERNIGHT...THERE IS A LOT OF UNCERTAINTY ON HOW THIS PERIOD IS GOING TO MATERIALIZE. THE 24.12Z NAM WHICH HAD A SLIGHTLY BETTER HANDLE ON THE SQUALL LINE PUSHED AN OUTFLOW BOUNDARY SOUTH TO THE MISSOURI AND IOWA BORDER...THUS ITS BEST MOISTURE TRANSPORT IS FOCUSED MUCH FURTHER SOUTH. THE 925 MB MOISTURE TRANSPORT HAS SHIFTED TOWARD SOUTHERN IOWA. IF THIS VERIFIES... MUCH OF THE PRECIPITATION WOULD REMAIN SOUTH OF THE AREA FOR THIS TIME PERIOD. EVEN THE LATEST RAP IS LEANING TOWARD THIS SCENARIO TOO. MEANWHILE BOTH THE ECMWF AND GEM MODELS SUGGEST THAT AS THE SHORT WAVE IN THE SOUTHERN PLAINS MOVES NORTHEAST INTO THE SOUTHERN PLAINS...THE 850 MB MOISTURE TRANSPORT SHIFTS BACK NORTHWARD TOWARD THE AREA TOWARD SUNRISE. IF THIS SCENARIO VERIFIES...THERE COULD BE A POTENTIAL FOR THE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATE TONIGHT. WITH ITS PRECIPTABLE WATER VALUE CLOSE TO 2.00 INCHES AND WARM CLOUD LAYER DEPTHS UP TO 4.5 KM...THERE WOULD BE THE POTENTIAL FOR HEAVY RAIN. WITH SO MANY DIVERSE MODEL SOLUTIONS...OPTED TO LOWER THE PRECIPITATION CHANCES SOME AND ALSO SHIFTED THE HIGHER CHANCES TO LATER IN THE NIGHT. HOPEFULLY...THE 24.00Z MODELS WILL BE BETTER AT RESOLVING THE STABLE LAYER THAT WAS LEFT IN THE WAKE OF THE SQUALL LINE. ON TUESDAY...EXPECT THE 925 MB AND 850 MB MOISTURE TRANSPORT TO INCREASE ACROSS IOWA. HOWEVER THERE IS SOME UNCERTAINTY HOW FAR NORTH THIS OCCUR. THE 24.18Z NAM AND 24.12Z GFS WOULD SUGGEST THAT THE HEAVIEST RAIN WOULD FALL ACROSS CENTRAL IOWA. MEANWHILE THE 24.12Z ECMWF AND GEM WOULD SUGGEST THAT THE HEAVIEST RAIN WOULD FALL SOUTH OF INTERSTATE 90. WITH THE INITIAL CONDITIONS SO MUDDLED...CONFIDENCE IS NOT THAT HIGH. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 304 PM CDT MON JUN 24 2013 ON TUESDAY NIGHT...MUCH OF THIS TIME PERIOD REMAINS UNCLEAR DUE TO UNCERTAINTIES ON WHERE THE BOUNDARIES WILL END UP FROM TONIGHT AND WHERE THUNDERSTORMS DEVELOP ON TUESDAY. THE GEM AND ECMWF HAVE THEIR MESOSCALE CONVECTIVE COMPLEXES MOVING ALONG AND SOUTH OF THE INTERSTATE 94 CORRIDOR. MEANWHILE THE GFS AND NAM SUGGEST THAT THE MESOSCALE CONVECTIVE COMPLEX WILL DEVELOP ACROSS IOWA...AND THEN MOVES IT NORTHEAST WITH THE SHORT WAVE INTO THE FORECAST AREA. WITH WARM CLOUD LAYER DEPTHS OVER 4 KM AND PRECIPITABLE WATER VALUES AROUND 2 INCHES. THERE WILL BE THE POTENTIAL FOR SOME FLASH FLOODING. ON WEDNESDAY AND WEDNESDAY EVENING...ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS THE AREA AS THE LOW PRESSURE AREA MOVES EAST ACROSS THE AREA. PRECIPITABLE WATER VALUES SLOWLY DROP TO AROUND 1.60 INCHES AND THE WARM CLOUD LAYER DEPTHS FALL INTO THE 3 TO 3.5 KM RANGE. WHILE THERE WILL BE THE POTENTIAL FOR SOME HEAVY RAIN...THE AMOUNTS LOOK TO BE MUCH LESS THAN WHAT THEY ARE FROM TONIGHT INTO TUESDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1222 AM CDT TUE JUN 25 2013 COMPLEX OF STORMS HAS DEVELOPED OVER THE AREA THIS EVENING AHEAD OF A SHORT WAVE TROUGH AND WITH THE LOW LEVEL JET AIMED RIGHT AT THE AREA. ACTIVITY CONTINUES TO BE PROGRESSIVE BUT DOES CONTINUE TO REDEVELOP BACK ACROSS SOUTH CENTRAL MINNESOTA. THE 25.03Z HRRR SEEMS TO HAVE A GOOD HANDLE ON THE SITUATION AND SHOWS THE CONVECTION CONTINUING THROUGH ABOUT 10Z OR SO WHEN THE SHORT WAVE TROUGH STARTS TO MOVE OFF TO THE EAST AND THE LOW LEVEL MOISTURE TRANSPORT STARTS TO REFOCUS BACK ON THE ON GOING ACTIVITY ACROSS NEBRASKA AND KANSAS. PLAN TO CARRY A TEMPO GROUP FOR THUNDER AT BOTH SITES THROUGH 10Z AND THEN SHOW VCTS INTO THE MIDDLE OF TUESDAY MORNING JUST IN CASE THE ACTIVITY IS SLOWER TO MOVE OUT. SHOULD SEE A BREAK FOR LATE MORNING INTO THE AFTERNOON BEFORE THE NEXT ROUND DEVELOPS. SEVERAL OF THE MODELS ARE SHOWING THE MAIN WARM FRONT LIFTING NORTH TOWARD THE AREA. THE FRONT HAS BEEN MOVING AND IS NOW INTO SOUTHERN IOWA SO NOT OUT OF THE QUESTION FOR IT TO BE NEAR THE AREA BY TUESDAY AFTERNOON. THE LOW LEVEL MOISTURE TRANSPORT RAPIDLY INCREASES DURING THE AFTERNOON INTO THE FRONT AHEAD OF THE MAIN UPPER LEVEL TROUGH WITH CONVECTION EXPECTED TO RAPIDLY DEVELOP IN THE AFTERNOON. HAVE INCLUDED VCTS FOR BOTH SITES TO SHOW THIS POSSIBILITY AND LATER FORECASTS WILL HAVE TO DETAIL THIS BETTER WHEN THE DETAILS BECOME CLEARER AS TO WHERE THESE STORMS WILL DEVELOP. && .HYDROLOGY... ISSUED AT 304 PM CDT MON JUN 24 2013 WITH A WIDE VARIETY OF SOLUTIONS IN THE 24.12Z AND 24.18Z MODELS...CONFIDENCE HAS LOWERED ON THE THREAT FOR FLASH FLOODING TONIGHT. HOWEVER WITH MANY RIVERS REMAINING EITHER HIGH OR ARE FLOODING ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN. CONFIDENCE WAS NOT HIGH ENOUGH TO CANCEL THE FLASH FLOOD WATCH. LOOKING AHEAD TO TUESDAY AND TUESDAY NIGHT...SOME MODELS SUGGEST THAT HEAVY RAIN COULD FALL SOUTH OF INTERSTATE 94. MEANWHILE OTHER MODELS HINT THAT THE HEAVIEST PRECIPITATION WILL REMAIN SOUTH OF THE FORECAST AREA. WITH SUCH DIVERSE SPREADS IN THE MODELS...OPTED NOT TO EXTEND THE FLASH FLOOD WATCH INTO TUESDAY NIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH UNTIL 10 AM CDT TUESDAY FOR WIZ032>034-041>044- 053>055-061. MN...FLASH FLOOD WATCH UNTIL 10 AM CDT TUESDAY FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH UNTIL 10 AM CDT TUESDAY FOR IAZ008>011-018-019- 029-030. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04 HYDROLOGY...BOYNE
AREA FORECAST DISCUSSION
NWS MIAMI FL
420 AM EDT THU JUN 27 2013 .DISCUSSION... AN IMPRESSIVE RIDGE OF HIGH PRESSURE OVER THE FOUR CORNERS REGION WILL ALLOW FOR AN UNUSUALLY DEEP TROUGH TO DEVELOP OVER THE EASTERN CONUS INTO THE WEEKEND. THE TROUGH WILL DIG SOUTHWARD INTO THE SOUTHEAST ON FRIDAY AND INTO NORTH FLORIDA OVER THE WEEKEND. THE SURFACE RIDGE AXIS WILL PUSH SOUTHWARD TO NEAR LAKE OKEECHOBEE THIS AFTERNOON AND THEN SLIDE SOUTH OF THE REGION ON FRIDAY THROUGH THE WEEKEND. ISOLATED SHOWERS WERE BEGINNING TO DEVELOP OVER THE ATLANTIC AND ACROSS PALM BEACH COUNTY. HRRR AND OTHER HIGH RES MODELS INDICATE SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP VERY NEAR THE COAST ALONG THE SEA BREEZE THIS MORNING...WITH SCATTERED TO NUMEROUS SHOWERS AND STORMS DEVELOPING ACROSS THE INTERIOR AND WEST INTO THE AFTERNOON. WATERSPOUTS ARE POSSIBLE OVER THE ATLANTIC WATERS...MAINLY THIS MORNING. IN ADDITION...SLOW MOVING STORMS COULD LEAD TO LOCALIZED FLOODING ACROSS THE REGION. SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE EVENING HOURS ACROSS THE INTERIOR...WITH RAIN CHANCES SHIFTING TO THE COASTAL REGIONS OVERNIGHT. THE UPPER TROUGH OVER THE OHIO VALLEY WILL GET REINFORCED AND AMPLIFY FRIDAY INTO THE WEEKEND BY A SERIES OF SHORTWAVES ROTATING SOUTHWARD OUT OF CANADA. A MORE SOUTHERLY FLOW WILL DEVELOP ON FRIDAY AS THE UPPER LEVEL TROUGH DEEPENS INTO THE SOUTHEAST AND THE RIDGE PUSHES SOUTH AND EAST. PRECIPITABLE WATER VALUES WILL REMAIN NEAR 2 INCHES...AND WEAK STEERING FLOW WILL MAINTAIN A LOCALLY HEAVY RAINFALL THREAT ONCE AGAIN. SOUTH TO SOUTHWEST FLOW WILL THEN DEVELOP OVER THE WEEKEND WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY. THE UPPER LEVEL TROUGH WILL BEGIN TO RETROGRADE INTO THE MIDDLE OF THE NATION EARLY NEXT WEEK. THE FLOW WILL THEN SHIFT BACK TO THE SOUTHEAST. HOWEVER...DEEP MOISTURE WILL REMAIN ACROSS THE REGION...WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY. && .AVIATION... VFR CONDITIONS ARE EXPECTED FOR THIS MORNING FOR ALL TERMINALS. INCREASING MOISTURE BY DAYBREAK COULD TRIGGER A FEW SHOWERS OVER THE ATLANTIC COASTAL WATERS. WINDS TURN SOUTHEASTERLY TODAY AND MORE SOUTHERLY ON FRIDAY. KEPT VCSH FOR ALL TERMINALS STARTING AROUND 14Z. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER THE COASTAL WATERS AS THE DAY PROGRESSES WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS IN THE INTERIOR SECTIONS IN THE AFTERNOON AND EVENING. && .MARINE... BY FRIDAY AND INTO THE WEEKEND SOUTHERLY TO SOUTHWESTERLY WINDS MAINLY BELOW 15 KNOTS ARE FORECAST ACROSS THE REGIONAL WATERS WITH GULF AND ATLANTIC SEAS 3 FEET OR BELOW THROUGH THE FORECAST PERIOD. && .FIRE WEATHER... AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS THE PENINSULA THURSDAY AND FRIDAY AFTERNOONS AND EARLY EVENING. OTHERWISE NO OTHER FIRE WEATHER CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 76 89 78 / 30 30 60 40 FORT LAUDERDALE 89 78 89 75 / 20 30 50 30 MIAMI 90 77 89 77 / 20 30 40 30 NAPLES 90 74 88 76 / 40 20 40 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...84/AK AVIATION/RADAR...71/JE
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
351 AM EDT THU JUN 27 2013 .SHORT TERM...(TODAY AND TONIGHT) OVER THE LAST FEW HOURS LARGE THUNDERSTORM COMPLEX OVER THE TN VALLEY HAS MOVED INTO NORTHERN AL AND WESTERN NC. ONLY A FEW SHOWERS/ISO THUNDERSTORMS HAVE MADE IT INTO NORTHERN GA. THE HRRR HAS A VERY GOOD HANDLE ON THE SYSTEM. IR IMAGERY SHOWS COPIOUS AMOUNTS OF CLOUD DEBRIS SPREADING INTO NORTHERN GA THIS MORNING. IF THE CLOUD COVER HOLDS...THIS MAY HELP LIMIT INSTABILITY ACROSS THE NORTHERN ZONES. HRRR IS HINTING THAT THE COMPLEX WILL LAY OUT AN OUTFLOW BOUNDARY ACROSS NORTH GA THIS MORNING. THIS SCENARIO SEEMS REASONABLE AND EXPECT LATE MORNING/AFT THUNDERSTORMS TO FILL IN ACROSS THE SOUTHERN TWO THIRDS OF THE FORECAST AREA AS THE ATMOS DESTABILIZES. STORMS WILL HAVE THE POTENTIAL TO BECOME SEVERE...WITH DAMAGING WIND GUSTS AND LARGE HAIL POSSIBLE. IN ADDITION...WITH PWATS AOA 2 INCHES...LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE. EXPECT CONVECTION TO DIMINISH IN THE EVENING WITH THE LOSS OF HEATING. EXACTLY WHERE CONVECTION WILL DEVELOP THIS AFTERNOON WILL HEAVILY DEPEND UPON WHERE THE OUTFLOW BOUNDARY SETS UP. IN ADDITION...THICKER CLOUD COVER TO THE NORTH COULD HELP LIMIT THUNDERSTORM DEVELOPMENT. HAVE PLACED THE HIGHEST POPS IN THE NORTH FOR THE FIRST PART OF THE DAY. MAY HAVE TO MAKE SOME ALTERATIONS LATER THIS MORNING...DEPENDING UPON IF ANY OF THE SHOWERS OVER NORTHERN GA MAKE IT DOWN TO THE METRO. THE HIGHEST POPS SHOULD BE SOUTH OF THE METRO AREA DURING THE LATE AFTERNOON AND EARLY EVENING. NLISTEMAA .LONG TERM /FRIDAY THROUGH WEDNESDAY/... FRIDAY BEGINS WITH ONE WAVE OF SHORTWAVE ENERGY EXITING OFF THE SE ATLANTIC COAST WHILE A SECOND SYSTEM LOOKS POISED TO DROP THROUGH THE TENNESSEE VALLEY AND INTO THE LOCAL AREA FRIDAY AFTERNOON. AT THIS TIME...INSTABILITY LOOKS TO BE ADEQUATE FOR NUMEROUS THUNDERSTORMS TO DEVELOP BUT LESS THAN PREVIOUS DAYS VALUES AND WITH LIMITED SHEAR VALUES IN PLACE...ONLY ISOLATED SEVERE STORMS WITH THIS COMPLEX ARE EXPECTED AT THIS TIME. WITH SURFACE TROUGH AXIS AND CONTINUED IMPULSES ROTATING THROUGH THE BASE OF THE TROUGH...POPS WILL REMAIN HIGHER THAN CLIMO THROUGH THE OVERNIGHT PERIOD AND HAVE REFLECTED THIS TREND IN THE LATEST GRID SET. MAIN MOISTURE AXIS WILL SHIFT SOUTH FOR SATURDAY BUT ADDITIONAL STRONG IMPULSE WILL MOVE ON THE DOORSTEP OF NORTH GA BY LATE EVENING. WILL KEEP HIGHEST POPS WHERE BETTER MOISTURE IS WITH LIKELY TO THE SOUTH BUT WILL GO HIGHER THAN GUIDANCE FOR THE NORTH GIVEN BETTER UPPER SUPPORT. THE ACTUAL UPPER LOW WHICH WILL HAVE BEEN A SEMI PERMANENT FEATURE BY THIS POINT WILL FINALLY ROTATE SOUTHWARD SATURDAY NIGHT INTO SUNDAY. AGAIN...BETTER MOISTURE REMAINS OVER EXTREME SOUTHERN SECTIONS OF THE FORECAST AREA AND HAVE GONE LIKELY THERE AGAIN ALTHOUGH WENT HIGHER THAN GUIDANCE NORTH AGAIN WITH UPPER LOW. THROUGH THE REMAINDER OF THE PERIOD...UPPER LOW WEAKENS AND RETROGRADES WITH LESS UPPER SUPPORT. DESPITE THIS...SOUTHEAST FLOW TO BRING COPIOUS AMOUNTS OF MOISTURE TO THE AREA RESULTING IN POPS ABOVE CLIMO. THIS WILL ALSO KEEP TEMPS BELOW CLIMO FOR THE REMAINDER OF THE LONG TERM PERIOD AS WELL. DEESE && .PREV DISCUSSION... /ISSUED 145 AM EDT THU JUN 27 2013/ PREV DISCUSSION... /ISSUED 1020 PM EDT WED JUN 26 2013/ UPDATE... HAVE REMOVED POPS FOR THE NIGHT EXCEPT FOR THE NORTHERN ZONES. THE THUNDERSTORM COMPLEX MOVING SOUTH THROUGH KENTUCKY STILL EXPECTED TO AFFECT NORTH GA BEFORE SUNRISE IF IT HOLDS TOGETHER. 41 PREVIOUS... SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... WITH NORTHWEST FLOW ALOFT...EXPECT RIPPLES IN THE FLOW TO CONTINUE ENHANCING THUNDERSTORMS THE REST OF TODAY. SCATTERED THUNDERSTORMS ARE POSSIBLE ACROSS NORTH AND EAST CENTRAL GEORGIA THE REST OF TODAY AND INTO TONIGHT. THE MAIN CONCERN IN THE SHORT TERM IS THE POSSIBLE DEVELOPMENT OF A MCS ACROSS THE OHIO RIVER VALLEY TONIGHT. 06Z AND 12Z GFS SUGGEST ANYWHERE FROM 25 TO 35 KNOTS OF 0-6 KM SHEAR ACROSS NORTH AND WEST CENTRAL GEORGIA LATE TONIGHT AND INTO THE AM TOMORROW. WITH ABUNDANT LOW LEVEL MOISTURE...HIRES MODELS HAVE CONSISTENTLY PREDICTED A MCS THAT FORMS OVER SOUTHERN INDIANA AND THEN DIVES SOUTH INTO MISSISSIPPI AND ALABAMA OVERNIGHT. THE SPC HAS INTRODUCED NORTH GEORGIA INTO A SLIGHT RISK FOR SEVERE WEATHER TODAY AND TONIGHT. THERE ARE A FEW POSSIBLE SCENARIOS WITH THE POTENTIAL MCS. 1. NO MCS FORMS. THESE SEEMS UNLIKELY AS CONVECTION IS ALREADY ONGOING IN SOUTHERN INDIANA. THE CURRENT MOTION OF THE MCS IS TO THE EAST AND WOULD LIKELY STAY NORTH OF OUR AREA...UNLESS THE HIRES MODELS ARE CORRECT AND THEN IT COULD DIVE SOUTH INTO OUR AREA. 2. THE MCS FORMS FURTHER TO THE SOUTH AND WEST...IN THIS CASE THE FLOW WOULD SUGGEST THAT A MCS WOULD MOVE THROUGH TENNESSEE AND KENTUCKY OVERNIGHT AND INTO THE AM AND THEN MOVE IN NORTH GEORGIA AROUND THE MORNING RUSH HOUR. 3. THE HIRES MODELS ARE RIGHT AND STORMS FORM OVER MO AND DIVE SOUTH INTO MISSISSIPPI AND ALABAMA. IN THIS CASE WE WOULD SEE OUR FAR WESTERN COUNTIES EXPERIENCE PART OF THE MCS IN THE AM. BELIEVE THAT ONE OF THE LATTER TWO POSSIBILITIES WILL BE POSSIBLE. AS SUCH...INTRODUCED LIKELY POPS ACROSS THE CWA FOR TOMORROW. MAIN THREAT TOMORROW WITH ANY THUNDERSTORMS ARE STRONG TO SEVERE WIND GUSTS. AN ISOLATED WEAK TORNADO CANNOT BE RULED OUT. AS THE REMNANTS OF A MCS MOVES SOUTH THROUGH THE DAY...THE DEVELOPMENT OF SCATTERED THUNDERSTORMS SEEMS LIKELY ACROSS SOUTHERN GEORGIA DURING THE AFTERNOON. SOME OF THESE STORMS COULD ALSO BE STRONG. DEPENDING ON THE SPEED OF THE MCS...WE COULD GET ENOUGH HEATING TOMORROW FOR THUNDERSTORMS TO REFORM ACROSS NORTH GEORGIA AS WELL. ARG LONG TERM /FRIDAY THROUGH WEDNESDAY/... MAIN ADJUSTMENT TO LONG TERM WAS TO LOWER POPS ACROSS PORTIONS OF THE NORTH ON SATURDAY BASED ON PROGGED MOISTURE/FORCING IN RECENT GUIDANCE AND OTHER OFFICE COLLABORATION. OTHERWISE ONLY MINOR OTHER ADJUSTMENTS MADE AND FORECAST LOOKS TO BE GENERALLY ON TRACK. PREVIOUS DISCUSSION FOLLOWS... BAKER PREV DISCUSSION... /ISSUED 416 AM EDT WED JUN 26 2013/ LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... LONG TERM PERIOD BEGINS WITH FIRST SHORTWAVE EXITING TO THE SOUTHEAST BUT ANOTHER RIGHT ON ITS HEELS FOR FRIDAY MORNING WITH PERTURBATIONS IN MEAN TROUGH FLOW ALLOWING FOR ROBUST CONVECTIVE DEVELOPMENT OVER NORTHERN SECTIONS OF THE FORECAST AREA. GFS ACTUALLY CARRIES AN ADDITIONAL EAVE INTO NORTH GA LATE FRIDAY AFTERNOON RESULTING IN MULTIPLE ROUNDS OF CONVECTION. ECMWF NOT AS AGGRESSIVE IN GENERATING THE SHORTWAVES IN THE MEAN FLOW BUT STILL GENERATES AND SINGLE WAVE OF ENHANCED PRECIP CHANCES FOR NORTH GA FRIDAY AFTERNOON. GFS SHOWS MAIN WAVE PUSHING THROUGH THE FORECAST AREA THROUGH SAT AFTERNOON WITH POPS DECREASING TO JUST SLIGHT CHANCE FOR THE NORTH BUT STILL CLOSE TO LOW END LIKELY FOR THE SOUTH. RESPITE LOOKS TO BE SHORTLIVED FOR THE NORTHERN HALF HOWEVER AS STRONG SPOKE OF MEAN TROUGH ROTATES THROUGH AND SURGES PRECIP BACK INTO THE AREA FROM THE SW AND WILL ADJUST POPS ACCORDINGLY. FOR THE REMAINDER OF THE PERIOD...AREA TRANSITIONS FROM EAST SIDE OF UPPER RIDGE TO BEING MORE INFLUENCED BY THE THROUGH ITSELF. GFS INDICATES POTENT WAVES ALONG THE TROUGH AND SHOULD SEE CONTINUED ELEVATED CHANCE OF THUNDERSTORMS THROUGH THE REMAINDER OF THE LONG TERM PERIOD. DEESE .AVIATION... 06Z UPDATE... THUNDERSTORM TIMING WILL BE THE FORECAST ISSUE OF THE DAY. COMPLEX OVER THE TN VALLEY IS PROGGED BY THE HRRR TO WEAKEN AS IT APPROACHES NORTHERN GA AND PRODUCE AN OUTFLOW BOUNDARY THAT CONVECTION WILL LIKELY FIRE UPON LATER THIS AFTERNOON. LOOKS LIKE THE BEST TIMING OF STORMS AT ATL WOULD BE BETWEEN 13Z AND 16Z. HOWEVER...MAY HAVE TO EXAMINE MODELS FURTHER IN CASE COMPLEX DOESN`T STABILIZE THE ATMOS AND THE POTENTIAL FOR STORMS CONTINUE IN THE AFT. //ATL CONFIDENCE...06Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. NLISTEMAA && .PRELIMINARY POINT TEMPS/POPS... ATHENS 88 71 96 69 / 60 50 40 60 ATLANTA 87 72 93 71 / 60 40 40 60 BLAIRSVILLE 81 67 86 64 / 60 30 60 30 CARTERSVILLE 87 71 95 68 / 60 30 60 60 COLUMBUS 90 73 96 73 / 60 50 40 60 GAINESVILLE 86 70 92 69 / 60 30 50 60 MACON 89 72 96 72 / 60 50 30 60 ROME 89 71 96 67 / 60 30 60 40 PEACHTREE CITY 87 71 95 69 / 60 50 40 60 VIDALIA 90 74 95 75 / 60 60 50 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...NLISTEMAA LONG TERM....DEESE AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
145 AM EDT THU JUN 27 2013 .PREV DISCUSSION... /ISSUED 1020 PM EDT WED JUN 26 2013/ UPDATE... HAVE REMOVED POPS FOR THE NIGHT EXCEPT FOR THE NORTHERN ZONES. THE THUNDERSTORM COMPLEX MOVING SOUTH THROUGH KENTUCKY STILL EXPECTED TO AFFECT NORTH GA BEFORE SUNRISE IF IT HOLDS TOGETHER. 41 PREVIOUS... SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... WITH NORTHWEST FLOW ALOFT...EXPECT RIPPLES IN THE FLOW TO CONTINUE ENHANCING THUNDERSTORMS THE REST OF TODAY. SCATTERED THUNDERSTORMS ARE POSSIBLE ACROSS NORTH AND EAST CENTRAL GEORGIA THE REST OF TODAY AND INTO TONIGHT. THE MAIN CONCERN IN THE SHORT TERM IS THE POSSIBLE DEVELOPMENT OF A MCS ACROSS THE OHIO RIVER VALLEY TONIGHT. 06Z AND 12Z GFS SUGGEST ANYWHERE FROM 25 TO 35 KNOTS OF 0-6 KM SHEAR ACROSS NORTH AND WEST CENTRAL GEORGIA LATE TONIGHT AND INTO THE AM TOMORROW. WITH ABUNDANT LOW LEVEL MOISTURE...HIRES MODELS HAVE CONSISTENTLY PREDICTED A MCS THAT FORMS OVER SOUTHERN INDIANA AND THEN DIVES SOUTH INTO MISSISSIPPI AND ALABAMA OVERNIGHT. THE SPC HAS INTRODUCED NORTH GEORGIA INTO A SLIGHT RISK FOR SEVERE WEATHER TODAY AND TONIGHT. THERE ARE A FEW POSSIBLE SCENARIOS WITH THE POTENTIAL MCS. 1. NO MCS FORMS. THESE SEEMS UNLIKELY AS CONVECTION IS ALREADY ONGOING IN SOUTHERN INDIANA. THE CURRENT MOTION OF THE MCS IS TO THE EAST AND WOULD LIKELY STAY NORTH OF OUR AREA...UNLESS THE HIRES MODELS ARE CORRECT AND THEN IT COULD DIVE SOUTH INTO OUR AREA. 2. THE MCS FORMS FURTHER TO THE SOUTH AND WEST...IN THIS CASE THE FLOW WOULD SUGGEST THAT A MCS WOULD MOVE THROUGH TENNESSEE AND KENTUCKY OVERNIGHT AND INTO THE AM AND THEN MOVE IN NORTH GEORGIA AROUND THE MORNING RUSH HOUR. 3. THE HIRES MODELS ARE RIGHT AND STORMS FORM OVER MO AND DIVE SOUTH INTO MISSISSIPPI AND ALABAMA. IN THIS CASE WE WOULD SEE OUR FAR WESTERN COUNTIES EXPERIENCE PART OF THE MCS IN THE AM. BELIEVE THAT ONE OF THE LATTER TWO POSSIBILITIES WILL BE POSSIBLE. AS SUCH...INTRODUCED LIKELY POPS ACROSS THE CWA FOR TOMORROW. MAIN THREAT TOMORROW WITH ANY THUNDERSTORMS ARE STRONG TO SEVERE WIND GUSTS. AN ISOLATED WEAK TORNADO CANNOT BE RULED OUT. AS THE REMNANTS OF A MCS MOVES SOUTH THROUGH THE DAY...THE DEVELOPMENT OF SCATTERED THUNDERSTORMS SEEMS LIKELY ACROSS SOUTHERN GEORGIA DURING THE AFTERNOON. SOME OF THESE STORMS COULD ALSO BE STRONG. DEPENDING ON THE SPEED OF THE MCS...WE COULD GET ENOUGH HEATING TOMORROW FOR THUNDERSTORMS TO REFORM ACROSS NORTH GEORGIA AS WELL. ARG LONG TERM /FRIDAY THROUGH WEDNESDAY/... MAIN ADJUSTMENT TO LONG TERM WAS TO LOWER POPS ACROSS PORTIONS OF THE NORTH ON SATURDAY BASED ON PROGGED MOISTURE/FORCING IN RECENT GUIDANCE AND OTHER OFFICE COLLABORATION. OTHERWISE ONLY MINOR OTHER ADJUSTMENTS MADE AND FORECAST LOOKS TO BE GENERALLY ON TRACK. PREVIOUS DISCUSSION FOLLOWS... BAKER PREV DISCUSSION... /ISSUED 416 AM EDT WED JUN 26 2013/ LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... LONG TERM PERIOD BEGINS WITH FIRST SHORTWAVE EXITING TO THE SOUTHEAST BUT ANOTHER RIGHT ON ITS HEELS FOR FRIDAY MORNING WITH PERTURBATIONS IN MEAN TROUGH FLOW ALLOWING FOR ROBUST CONVECTIVE DEVELOPMENT OVER NORTHERN SECTIONS OF THE FORECAST AREA. GFS ACTUALLY CARRIES AN ADDITIONAL EAVE INTO NORTH GA LATE FRIDAY AFTERNOON RESULTING IN MULTIPLE ROUNDS OF CONVECTION. ECMWF NOT AS AGGRESSIVE IN GENERATING THE SHORTWAVES IN THE MEAN FLOW BUT STILL GENERATES AND SINGLE WAVE OF ENHANCED PRECIP CHANCES FOR NORTH GA FRIDAY AFTERNOON. GFS SHOWS MAIN WAVE PUSHING THROUGH THE FORECAST AREA THROUGH SAT AFTERNOON WITH POPS DECREASING TO JUST SLIGHT CHANCE FOR THE NORTH BUT STILL CLOSE TO LOW END LIKELY FOR THE SOUTH. RESPITE LOOKS TO BE SHORTLIVED FOR THE NORTHERN HALF HOWEVER AS STRONG SPOKE OF MEAN TROUGH ROTATES THROUGH AND SURGES PRECIP BACK INTO THE AREA FROM THE SW AND WILL ADJUST POPS ACCORDINGLY. FOR THE REMAINDER OF THE PERIOD...AREA TRANSITIONS FROM EAST SIDE OF UPPER RIDGE TO BEING MORE INFLUENCED BY THE THROUGH ITSELF. GFS INDICATES POTENT WAVES ALONG THE TROUGH AND SHOULD SEE CONTINUED ELEVATED CHANCE OF THUNDERSTORMS THROUGH THE REMAINDER OF THE LONG TERM PERIOD. DEESE && .AVIATION... 06Z UPDATE... THUNDERSTORM TIMING WILL BE THE FORECAST ISSUE OF THE DAY. COMPLEX OVER THE TN VALLEY IS PROGGED BY THE HRRR TO WEAKEN AS IT APPROACHES NORTHERN GA AND PRODUCE AN OUTFLOW BOUNDARY THAT CONVECTION WILL LIKELY FIRE UPON LATER THIS AFTERNOON. LOOKS LIKE THE BEST TIMING OF STORMS AT ATL WOULD BE BETWEEN 13Z AND 16Z. HOWEVER...MAY HAVE TO EXAMINE MODELS FURTHER IN CASE COMPLEX DOESN`T STABILIZE THE ATMOS AND THE POTENTIAL FOR STORMS CONTINUE IN THE AFT. //ATL CONFIDENCE...06Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. NLISTEMAA && .PRELIMINARY POINT TEMPS/POPS... ATHENS 88 71 92 69 / 60 50 40 60 ATLANTA 87 72 91 70 / 60 40 40 60 BLAIRSVILLE 82 67 88 65 / 60 30 60 30 CARTERSVILLE 87 70 94 69 / 60 30 60 60 COLUMBUS 90 74 94 73 / 60 50 40 60 GAINESVILLE 86 71 92 69 / 60 30 50 60 MACON 89 72 93 72 / 60 50 30 60 ROME 89 70 96 69 / 60 30 60 40 PEACHTREE CITY 87 70 90 70 / 60 50 40 60 VIDALIA 92 74 91 74 / 60 60 50 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
407 AM CDT THU JUN 27 2013 .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * FOG/BR DEVELOPMENT EARLY THIS MORNING. * THUNDERSTORM CHANCES THIS AFTERNOON/EVENING. * INLAND EXTENT OF LAKE BREEZE THIS AFTERNOON. BMD //DISCUSSION...UPDATED 06Z... COLD FRONT PASSED THROUGH THE AREA LEAVING US UNDER NORTHWEST FLOW THROUGH THE FORECAST PERIOD. OVERNIGHT...VERY LIGHT WINDS...CALM OR VARIABLE AT TIMES...COUPLED WITH RECENT RAINFALL AND PARTIAL CLEARING OVERHEAD WILL HELP SET THE STAGE FOR FOG DEVELOPMENT. DOESNT APPEAR WE WILL COMPLETELY CLEAR OUT WHICH WILL HELP TO SOME DEGREE...BUT DEW POINT DEPRESSIONS ARE ALREADY ONLY A COUPLE/FEW DEGREES SO WONT TAKE MUCH COOLING THE REST OF TONIGHT TO BEGIN TO SATURATE AND SEE VSBY REDUCTIONS. IN ADDITION...SATURATED CONDITIONS OVER LAKE MICHIGAN MAY LEAD TO LOW CIGS OR FOG MOVING INLAND OVER GYY TONIGHT. EXPECT VSBY TO IMPROVE AND NORTHWEST FLOW TO PICK UP SOME SHORTLY AFTER DAYBREAK THURSDAY MORNING. SHOULD BE A QUIET FIRST HALF OF THE DAY...BUT BY EARLY AFTERNOON...MODELS SUGGEST THAT THE ATMOSPHERE WILL ONCE AGAIN BECOME UNSTABLE AND UNCAPPED LEADING TO THUNDERSTORMS DEVELOPING. APPEARS THE BEST TIME FRAME FOR TSTRMS TO IMPACT THE TERMINALS WILL BE MID TO LATE AFTERNOON AS A MID LEVEL DISTURBANCE MOVES OVERHEAD AS WELL AS A 100KT JET STREAK WHICH WILL PROVIDE ADDITIONAL LIFT. A LAKE BREEZE MAY DEVELOP IN THE RELATIVELY LIGHT NORTHWEST FLOW AT THE SURFACE...THOUGH IT IS NOT CURRENTLY EXPECTED TO MAKE IT AS FAR INLAND AS ORD/MDW. BMD //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN MVFR VSBY THIS MORNING...LOW CONFIDENCE IN DENSE FOG DEVELOPING. * MEDIUM CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING AT SOME POINT THIS AFTERNOON. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. BMD //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... * FRIDAY AND SATURDAY...CHANCE OF SHRA/TSRA. * SUNDAY...DRY. * MONDAY AND TUESDAY...SLIGHT CHANCE OF TSRA. && .MARINE... 304 AM CDT EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND. WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY THROUGH SUNDAY. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
402 AM CDT THU JUN 27 2013 .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * FOG/BR DEVELOPMENT EARLY THURSDAY MORNING. * THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING. * INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON. BMD //DISCUSSION...UPDATED 06Z... COLD FRONT PASSED THROUGH THE AREA LEAVING US UNDER NORTHWEST FLOW THROUGH THE FORECAST PERIOD. OVERNIGHT...VERY LIGHT WINDS...CALM OR VARIABLE AT TIMES...COUPLED WITH RECENT RAINFALL AND PARTIAL CLEARING OVERHEAD WILL HELP SET THE STAGE FOR FOG DEVELOPMENT. DOESNT APPEAR WE WILL COMPLETELY CLEAR OUT WHICH WILL HELP TO SOME DEGREE...BUT DEW POINT DEPRESSIONS ARE ALREADY ONLY A COUPLE/FEW DEGREES SO WONT TAKE MUCH COOLING THE REST OF TONIGHT TO BEGIN TO SATURATE AND SEE VSBY REDUCTIONS. IN ADDITION...SATURATED CONDITIONS OVER LAKE MICHIGAN MAY LEAD TO LOW CIGS OR FOG MOVING INLAND OVER GYY TONIGHT. EXPECT VSBY TO IMPROVE AND NORTHWEST FLOW TO PICK UP SOME SHORTLY AFTER DAYBREAK THURSDAY MORNING. SHOULD BE A QUIET FIRST HALF OF THE DAY...BUT BY EARLY AFTERNOON...MODELS SUGGEST THAT THE ATMOSPHERE WILL ONCE AGAIN BECOME UNSTABLE AND UNCAPPED LEADING TO THUNDERSTORMS DEVELOPING. APPEARS THE BEST TIME FRAME FOR TSTRMS TO IMPACT THE TERMINALS WILL BE MID TO LATE AFTERNOON AS A MID LEVEL DISTURBANCE MOVES OVERHEAD AS WELL AS A 100KT JET STREAK WHICH WILL PROVIDE ADDITIONAL LIFT. A LAKE BREEZE MAY DEVELOP IN THE RELATIVELY LIGHT NORTHWEST FLOW AT THE SURFACE...THOUGH IT IS NOT CURRENTLY EXPECTED TO MAKE IT AS FAR INLAND AS ORD/MDW. BMD //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE IN SOME REDUCTION TO VSBY OVERNIGHT...LOW CONFIDENCE IN DENSE FOG DEVELOPING. * MEDIUM CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING AT SOME POINT THURSDAY AFTERNOON. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. BMD //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... * FRIDAY AND SATURDAY...CHANCE OF SHRA/TSRA. * SUNDAY...DRY. * MONDAY AND TUESDAY...SLIGHT CHANCE OF TSRA. && .MARINE... 304 AM CDT EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND. WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY THROUGH SUNDAY. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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 DES MOINES IA
358 AM CDT THU JUN 27 2013 .SHORT TERM.../TODAY/... ISSUED AT 357 AM CDT THU JUN 27 2013 WEAK SHORTWAVE WILL CONTINUE TO CUT ACROSS EASTERN SD INTO EASTERN NE AND WESTERN IA THIS MORNING. THE HI-RES MODELS KEEP THE PRECIP CONFINED TO THE SOUTHWEST PORTIONS OF THE FORECAST AREA EXCEPT THE 06Z HRRR WHERE ITS FURTHER EAST AND IS A BIT MORE BULLISH WITH THE COVERAGE. LITTLE MOISTURE AND FORCING WITH THIS SYSTEM AND ANYTHING THAT DEVELOPS WILL BE HIGH BASED AND SO LEANED TOWARD THE HIRES-NMM MODEL RUNS AS IT SEEMED TO HAVE THE BEST SOLUTION WRT TO LOCATION AND TIMING OF PRECIP. CURRENT RADAR TRENDS HAVE THE PRECIP MOVING INTO THE WESTERN FORECAST AREA BY AROUND 10Z OR SHORTLY AFTER AND LOOK TO BE MORE SOUTHEAST. HOWEVER...THE LATEST RAP CORFIDI VECTORS AND STORM MOTION VECTORS SHIFT THE PRECIP MOVEMENT MORE SOUTHERLY AS IT MOVES EAST. HIGH TEMPS TODAY SHOULD BE FAIRLY SIMILAR TO WEDNESDAY...MAYBE SLIGHTLY COOLER OVER THE WEST TO SOUTH WHERE THE PRECIP AND MORE CLOUD COVER WILL BE THIS MORNING. WAS CONFIDENT ENOUGH TO GO ABOVE GUIDANCE FOR HIGHS TODAY. .LONG TERM.../TONIGHT THROUGH WEDNESDAY/... ISSUED AT 357 AM CDT THU JUN 27 2013 NO SIGNIFICANT CONCERNS THROUGH THIS PERIOD BUT WITH DEFINITE PATTERN CHANGE COMING. MCS MAY BE LINGERING OVER SRN IA AT 00Z WITH THERMODYNAMIC FORCING JUST EXITING INTO MO. THIS WILL LEAD TO FAIR WEATHER LATER THU NIGHT AND INTO EARLY FRI AS LONG WAVE PATTERN BEGINS TO AMPLIFY INTO WRN CONUS TROUGH/ERN RIDGE. HOWEVER BY FRI AFTERNOON REMNANTS OF CURRENT COMPACT MANITOBA SHORT WAVE WILL BEGIN DROPPING INTO WRN SIDE OF GREAT LAKES MEAN TROUGH. THIS WILL GRADUALLY INCREASE SUB 3KM MOISTURE NE-SW...AND COUPLED WITH DAYTIME HEATING...PRODUCE WEAK BUT UNCAPPED SEVERAL HUNDRED MLCAPES. THIS WILL LIKELY DEVELOP SCATTERED UNORGANIZED WEAK PEAK HEATING CONVECTION NE...WHICH IS DEPICTED IN NAM AND HI RES MODEL SIMULATED REFLECTIVITY. LATE DAY MIXING PRODUCING THE INSTABILITY WILL ALSO LIKELY ALLOW BRISK NW WINDS TO MIX DOWN AS SLP GRADIENT INCREASES WITH GUSTS AT OR ABOVE 30 MPH POSSIBLE CENTRAL AND NORTH. BY SATURDAY...THERE IS LITTLE EVIDENCE OF ANY QG FORCING AS AFOREMENTIONED VORT AXIS DROPS THROUGH MS VALLEY. MAIN RESULT WILL BE INCREASED DEEP MOISTURE WITH SOUNDINGS SHOWING NEAR SATURATION AT MANY SITES. THIS ENVIRONMENT WILL LIKELY PRODUCE AREAS OF LIGHT SHOWERS INTO SAT...POSSIBLY LINGERING INTO THE SE EARLY EVENING. HAVE RAISED POPS FURTHER THROUGH THE CHANCE CATEGORY. COULD SEE SOME THUNDER BUT NOTHING SEVERE ANTICIPATED. THE LONG WAVE PATTERN WILL CHANGE LITTLE TO END THE WEEKEND WITH PERSISTENT WEST/EAST TROUGH/RIDGE BUT WITH WEAKENING FLOW. SOME RETROGRESSION WILL EVEN OCCUR BY EARLY NEXT WEEK WITH TROUGH EVENTUALLY DRIFTING WWD INTO MS VALLEY. MID/LOWER TROPOSPHERIC FLOW WILL BE RATHER WEAK IN THIS TIME FRAME WITH LITTLE FORCING. THERE IS SOME POTENTIAL FOR PRECIP...BUT CONFIDENCE IN TIMING OR LOCATION IS NOT GREAT ENOUGH TO INCLUDE MENTION AT THE MOMENT. HOWEVER BY LATE TUE INTO WED TROUGH AND ASSOCIATED FORCING INCREASES SLIGHTLY WHICH JUSTIFIES LOW CHANCES BY THAT TIME. TEMPERATURE WISE...READINGS WILL BE BELOW NORMAL WITH CORRESPONDINGLY LOWER DEWPOINTS. FRIDAY COULD VERY WELL BE THE LAST DAY WE EXCEED 80F FOR THE DURATION OF THE PERIOD AREA WIDE. IN FACT GFS/ECMWF H85 TEMP TIME SERIES THROUGH THE FOLLOWING WEEKEND /JUL 6/ SHOWS LITTLE EVIDENCE OF ANY RETURN TO WARM AND HUMID WEATHER. && .AVIATION...27/06Z ISSUED AT 1156 PM CDT WED JUN 26 2013 VFR CONDITIONS THROUGHOUT THE TAF PERIOD. WESTERLY TO NORTHWESTERLY WINDS TO PICK UP THURSDAY BEFORE DIMINISHING WITH SUNSET THURSDAY EVENING. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...SMALL AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
342 AM CDT THU JUN 27 2013 .SYNOPSIS... ISSUED AT 340 AM CDT THU JUN 27 2013 STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT POPPED UP OVER NW IL THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT THU JUN 27 2013 MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO MAKE IT THIS FAR EAST. A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE SCATTERED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 340 AM CDT THU JUN 27 2013 INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION. THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN. SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1148 PM CDT WED JUN 26 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE REST OF THE NIGHT. THERE IS A LOW PROBABILITY OF FOG FORMATION DUE TO LIGHT WINDS AND LINGERING MOISTURE. CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE TAFS BEYOND A PERIOD OF OVERNIGHT VISIBILITIES IN THE RANGE OF 5SM TO 6SM. THURSDAY SHOULD REMAIN VFR WITH WINDS INCREASING TO 10 TO 20 KTS AND GUSTY FOR A PERIOD IN THE AFTERNOON. THERE IS A LOW POTENTIAL FOR THUNDERSTORMS...ESPECIALLY ALONG AND EAST OF THE DBQ AND MLI TERMINALS...BUT THIS POSSIBILITY IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...DMD SHORT TERM...DMD LONG TERM...14 AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1204 AM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 1148 PM CDT WED JUN 26 2013 MID AND UPPER LEVEL SUBSIDENCE ASSOCIATED WITH A PASSING MID LEVEL SHORTWAVE RIDGE AND RIGHT EXIT REGION OF A 90 KT UPPER LEVEL JET MOVING THROUGH THE NORTHERN PLAINS AND UPPER MS VALLEY HAS SQUELCHED CONVECTION OVER THE FORECAST AREA THIS EVENING. CONSIDERING THIS...AND A LACK OF LOW LEVEL CONVERGENCE...SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED THROUGH THE REST OF TONIGHT. SATELLITE IMAGES SHOW AN AREA OF CI UPSTREAM...WHICH SHOULD HELP LIMIT FOG FORMATION WHICH WOULD OTHERWISE BE MORE FAVORABLE GIVEN WEAK PRESSURE GRADIENT...LIGHT WINDS AND LINGERING HIGH DEWPOINTS AND MOIST SURFACE CONDITIONS FROM RECENT RAINS. THUS...HAVE KEPT FOG OUT OF THE FORECAST WITH ONLY MINOR TWEAKS IN EVENING UPDATES. && .SYNOPSIS... ISSUED AT 334 PM CDT WED JUN 26 2013 18Z SFC ANALYSIS HAS THE REMNANTS OF A MESO HIGH AT KDBQ AND A MESO LOW BETWEEN KSQI AND KFEP. AN OUTFLOW BOUNDARY FROM THE MCS RAN FROM LAKE MICHIGAN THROUGH CENTRAL ILLINOIS AND THEN TO NEAR KMXO. THE SYNOPTIC COLD FRONT RAN FROM NEAR KMSP...TO KDSM...TO KFNB. AHEAD OF THE SYNOPTIC FRONT SEVERAL WEAK TROFS/BOUNDARIES WERE ACROSS EASTERN IOWA AND MISSOURI. DEW POINTS WERE IN THE 70S WITH 60S OVER THE GREAT LAKES AND BEHIND THE COLD FRONT. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 334 PM CDT WED JUN 26 2013 DIURNAL CONVECTION HAS FIRED ALONG A THETA E GRADIENT IN CENTRAL IOWA AND ALONG A PRE-FRONTAL TROF. RAP TRENDS BRING THIS FEATURE INTO THE WESTERN CWFA LATE THIS AFTERNOON BEFORE WEAKENING THE THETA E GRADIENT. THUS THE NEW STORMS THAT HAVE DEVELOPED JUST WEST OF THE CWFA ARE EXPECTED TO MOVE INTO THE WESTERN CWFA DURING THE LATE AFTERNOON HOURS AND THEN SLOWLY DISSIPATE WITH SUNSET. AHEAD OF THIS CONVECTION...ISOLATED SHOWERS AND STORMS ARE EXPECTED TO DEVELOP DURING PEAK HEATING THAT WILL ALSO SLOWLY DISSIPATE WITH SUNSET. THE SYNOPTIC COLD FRONT WILL MOVE THROUGH THE CWFA TONIGHT DROPPING DEW POINTS ABOUT 5 TO 7 DEGREES. WINDS ARE EXPECTED TO BE FAIRLY LIGHT AND GIVEN THE WET GROUND IN SOME AREAS THERE IS A POTENTIAL FOR SOME FOG DEVELOPMENT AFTER MIDNIGHT. THIS WILL HAVE TO BE WATCHED TO SEE HOW IT WILL EVOLVE. QUIET AND DRY CONDITIONS WILL BE SEEN THURSDAY MORNING ACROSS THE AREA WHILE AN UPPER LOW MOVES INTO THE NORTHERN GREAT LAKES. DAY TIME HEATING COMBINED WITH SLIGHTLY COOLER AIR ALOFT SHOULD ALLOW NEW CONVECTION TO DEVELOP DURING THE AFTERNOON. THE LOWER MOISTURE LEVELS IN THE ATMOSPHERE AND NORTHWEST FLOW SHOULD RESULT IN THE CONVECTION BEING ISOLATED TO SCATTERED IN NATURE. ..08.. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 334 PM CDT WED JUN 26 2013 THURSDAY NIGHT AND FRIDAY...AS NORTHWESTERLY STEERING FLOW TAKES OVER WITH UPPER RIDGE RETROGRADE...DIGGING UPPER WAVE INTO THE NORTHWESTERN GRT LKS WILL CONNECT WITH TROF INTO THE CENTRAL PLAINS FOR CONTINUED ISOLATED TO WDLY SCTRD SHOWER/STORM THREAT INTO MID THU EVENING. BUT BEST FORCING AND CONVERGENCE TO REMAIN JUST TO THE NORTHEAST AND SOUTHWEST OF THE DVN CWA. WILL EXTEND LOW CHC POPS IN THE FAR EAST AND MAINTAIN ONGOING POPS IN THE SOUTHWESTERN CWA THROUGH 03Z FRI. AFTER TROF EMBEDDED IN NW STEERING FLOW PASSES...EXPECT SOME CLEARING AND COOLER CONDITIONS INTO EARLY FRI MORNING WITH LOWS WELL DOWN INTO THE 60S...POSSIBLY SOME LOWER 60S NORTH OF I80. LARGE UPPER CYCLONE COMPLEX TO THEN CONTINUE TO SETTLE ACRS THE HEART OF THE GRT LKS ON FRI. ASSOCIATED VORT SPOKE ALOFT AND MID LEVEL COOL POOL TO INDUCE DEEP STEEP LAPSE RATES AND A INSTABILITY SHOWER SET UP ACRS MN INTO WI AND IL. SOME POTENTIAL FOR THUNDERSTORMS WITH VERTICAL THERMODYNAMIC PROFILES SUPPORTIVE OF HAIL IF ENHANCED UPDRAFTS CAN MAINTAIN. THIS ACTIVITY MORE LIKELY FRIDAY AFTERNOON ACRS THE NORTHEASTERN THIRD OF THE DVN CWA AND WILL ADJUST POPS ACCORDINGLY. DESPITE INCOMING COOLER AIR INFLUX/ ADVECTION...DEEP MIXING PROFILES UP TO H8 MB STILL TO BOOST TEMPS INTO THE LOW TO MID 80S WHILE SFC DPTS DRY-DOWN MIX INTO THE LOWER 60S TO UPPER 50S...MAYBE LOWER THAN GUIDANCE SUGGESTS INTO THE MID 50S. BREEZY NORTHWEST WINDS AS WELL IN THIS SCENARIO OF 15 TO 20+ MPH. TIGHTENING CYCLONIC FLOW ALOFT MAY KEEP SHOWERS PECULATING WELL INTO FRI EVENING BEFORE NOCTURNAL PROCESSES TAKE OVER. EVEN WITH CLOUD DEBRIS...STILL A COOLER NIGHT WITH WIDESPREAD LOWS IN THE LOW TO MID 60S. SATURDAY AND SUNDAY...UNSTABLE VERTICAL PROFILES UNDER ONGOING CYCLONIC FLOW AND ANOTHER INCOMING VORT SPOKE MAY PRODUCE MORE WIDESPREAD SHOWERS AND A FEW STORMS/FURTHER TO THE WEST/THEN ON FRIDAY. CANADIAN LLVL RIDGE AXIS DUMPING DOWN TO THE WEST OF THE AREA ACRS THE PLAINS. FCST SOUNDING SUGGEST ANOTHER DAY OF DEEP MIXING... BUT CONTINUED LLVL COOL POOL INFLUX AS WELL AS SHOWERS/CLOUDS WILL HAVE A BETTER SHOT TO KEEP TEMPS IN THE 70S. CLEAR OUT SAT NIGHT AS LARGE STOUT CANADIAN HIGH TAKES GRIP OF THE UPPER MIDWEST AND COULD FOSTER WIDESPREAD LOWS WELL DOWN IN THE 50S BY EARLY SUNDAY MORNING. HIGH PRESSURE TO THEN TO MIGRATE TOWARD THE GRT LKS ON SUNDAY...WHILE ALOFT DEEP LONG WAVE TROF EXTENDS TO THE GULF ALONG AND EAST OF THE MS RVR VALLEY. APPEARS LESSENING CHANCE OF SHOWERS SUNDAY AND BOUNDARY LAYER NORTHEASTERLY FETCH AGAIN TO POSSIBLY KEEP TEMPS IN THE 70S FOR HIGHS. SUNDAY NIGHT SEASONABLY COOL AND WELL DOWN IN THE 50S ALONG AND NORTH OF I80. MONDAY THROUGH NEXT WEDNESDAY...LONG RANGE SIGNALS SUGGEST A GENERAL BLOCKED PATTERN WITH BOOKEND RIDGES ON THE COASTS AND MID CONUS L/W TROFFINESS PERSISTING THROUGH WED. BUT THEY ALSO SUGGEST IT TO START TO MODIFY AND BREAK DOWN THE L/W TROF FEATURE AFTER TUE. THUS IN GENERAL...BELOW NORMAL TEMPS LOOK TO CONTINUE IN THE VCNTY OF THIS UPPER TROF..AS WELL AS ALMOST A DAILY THREAT OF POP UP SHOWERS AND A FEW STORMS. BETTER CHANCES OFF THOUGH TO THE SOUTHEAST OF THE DVN CWA IN VCNTY OF UPPER LOW MON INTO TUE. ..12.. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1148 PM CDT WED JUN 26 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE REST OF THE NIGHT. THERE IS A LOW PROBABILITY OF FOG FORMATION DUE TO LIGHT WINDS AND LINGERING MOISTURE. CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE TAFS BEYOND A PERIOD OF OVERNIGHT VISIBILITIES IN THE RANGE OF 5SM TO 6SM. THURSDAY SHOULD REMAIN VFR WITH WINDS INCREASING TO 10 TO 20 KTS AND GUSTY FOR A PERIOD IN THE AFTERNOON. THERE IS A LOW POTENTIAL FOR THUNDERSTORMS...ESPECIALLY ALONG AND EAST OF THE DBQ AND MLI TERMINALS...BUT THIS POSSIBILITY IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...SHEETS SYNOPSIS...08 SHORT TERM...08 LONG TERM...12 AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
336 AM CDT THU JUN 27 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT THU JUN 27 2013 MID/UPPER LEVEL ISENTROPIC LIFT BEGINNING TO GENERATE VERY HIGH BASED CONVECTION ALONG AND JUST NORTH OF THE NEBRASKA/SOUTH DAKOTA BORDER EARLY THIS MORNING...GENERALLY NORTH OF MOST GUIDANCE HAS SUGGESTED. 00Z 700MB OBSERVED TEMPS WERE RATHER MODEST IN THE LOWER TEENS GIVEN 850MB TEMPS IN THE MID 20S C. 07Z SURFACE OBS SHOWED INCREASING EVIDENCE OF A COLD FRONT FROM NORTHERN COLORADO TO NORTH CENTRAL NEBRASKA. UPPER FLOW ON TRACK TO TRANSITION FROM NEARLY WESTERLY TO NEARLY NORTHERLY THROUGH TONIGHT...HELPING PUSH THE COLD FRONT SOUTHEAST THROUGH THE REGION. TIMING FOR THE LOCAL AREA SHOULD BE IN THE MID AFTERNOON TO EARLY MORNING HOURS...WITH MODEL SOUNDINGS SUGGESTING VERY LITTLE MIXED LAYER CIN BY EARLY AFTERNOON /WHICH IS REASONABLE GIVEN THE AFOREMENTIONED MODEST MID LEVEL TEMPS/ AND LARGE TO EXTREME INSTABILITY WITH DEWPOINTS AROUND 70F AND TEMPS AGAIN NEAR THE CENTURY MARK. CONFIDENCE IN LOW LEVEL CONDITIONS THOUGH NOT HIGH IS INCREASING WITH TIME AS THE CURRENT CONVECTION REMAINS NORTH AND SHOULD KEEP THE BOUNDARY LAYER UNMARRED BY RAIN/OUTFLOW. HEAT INDEX VALUES IN THE 104-109 RANGE REMAIN ON TARGET AND WILL LEAVE THE HEAT ADVISORY GOING AS-IS. NORTHWEST 500MB WINDS AROUND 45KT AND SOUTH TO SOUTHWEST SURFACE WINDS WILL BRING DEEP LAYER SHEAR TO NEAR 50KT AND COMBINE WITH THE INSTABILITY TO EASILY SUPPORT SUPERCELL STRUCTURES WITH THE SHEAR VECTORS NEARLY PERPENDICULAR TO THE BOUNDARY. VERY LARGE HAIL WOULD BE HIGH ON THE LIST OF CONCERN WITH INITIAL CONVECTION WITH HIGH LCL HEIGHTS AND LIMITED LOW LEVEL SHEAR KEEPING TORNADO RISK MORE IN CHECK. LOW CIN AND THE PRESENCES OF THE PROGRESSIVE BOUNDARY SHOULD ALLOW STORMS TO CONGEAL TO MORE LINEAR STRUCTURES WITH TIME AND LESSEN THE VERY LARGE HAIL CHANCES AFTER EARLY EVENING. THE HIGH BASES AND POTENTIAL FOR DOWNDRAFT CAPE WELL OVER 1000 J/KG WILL BRING DAMAGING WIND CONCERNS AS WELL. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 313 AM CDT THU JUN 27 2013 QUITE A PATTERN CHANGE ON THE WAY FRIDAY INTO THE WEEKEND. COOL CANADIAN HIGH PRESSURE SURGES SOUTHWARD UNDER NORTHERLY FLOW ALOFT...DROPPING TEMPERATURES TO AROUND 90 FRIDAY WITH A FALL IN TO THE 80S TO LOWER 80S BY THE END OF THE WEEKEND. HIGHLY AMPLIFIED MERIDIONAL UPPER PATTERN CONTINUES THROUGH TUESDAY...WITH ANOTHER PIECE OF ENERGY ROTATING THROUGH THE FLOW INTO THE BACKSIDE OF THE UPPER EASTERN TROF...POSSIBLY RETROGRADING IT BACK WESTWARD OVER THE CENTRAL PLAINS BY MID WEEK. THIS WOULD BRING INCREASED CHANCE FOR PRECIP TOWARD WEDNESDAY AND WILL REFLECT IN FORECAST. ALSO STILL A SIGNAL FOR AN IMPULSE TO MOVE ACROSS THE EAST ON SUNDAY AND WILL CARRY SLIGHT CHANCE THEN AS WELL. OTHERWISE A DRY AND BELOW NORMAL FORECAST FOR THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1145 PM CDT WED JUN 26 2013 CONFIDENCE IN THE CONVECTIVE FORECAST FOR TOMORROW IS LOW. MODELS HAVE SHOWN LITTLE CONTINUITY WITH THE POSSIBILITY FOR ELEVATED NOCTURNAL STORMS. THE RAP AND HRRR IN PARTICULAR BRING ELEVATED STORMS FROM NEB INTO THE AREA EARLY IN THE DAY. IF THIS IS THE CASE...THERE COULD BE SCT STORMS THROUGH MUCH OF THE DAY. UNTIL ELEVATED STORMS BECOME APPARENT...THE FORECAST REMAINS CONSERVATIVE THINKING THE HIGHEST PROB FOR STORMS WILL BE DURING THE PEAK HEATING OF THE DAY. LOW LEVEL CONVERGENCE ALONG A WEAK SFC BOUNDARY AND A VERY UNSTABLE AIRMASS COULD LEAD TO EXPLOSIVE DEVELOPMENT IF MORNING SHOWERS AND THUNDERSTORMS DO NOT FORM. ANTICIPATE VFR CONDITIONS TO PREVAIL UNLESS CONVECTION MOVES OVER THE TERMINALS. && .TOP WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING FOR KSZ008-009-020>023-026-034>040-054>056-058-059. && $$ SHORT TERM...65 LONG TERM...67 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1145 PM CDT WED JUN 26 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 348 PM CDT WED JUN 26 2013 TONIGHT THROUGH THURSDAY... THE BROAD RIDGE CENTERED OVER THE ROCKY MOUNTAINS WILL CONTINUE TO AMPLIFY NORTHWARD TONIGHT INTO TOMORROW AS THE MID LEVEL TROUGH GRADUALLY DIGS FURTHER SOUTH ACROSS THE EASTERN U.S. ANOTHER MILD NIGHT IS IN STORE FOR THE REGION AS SURFACE HIGH PRESSURE WEST OF THE AREA TODAY PROGRESSES EAST OVER THE AREA TONIGHT...RESULTING IN LIGHT WINDS VEERING TOWARD THE SOUTHEAST BY THURSDAY MORNING. THESE WINDS COMBINED WITH WARM CONDITIONS ALREADY IN PLACE FROM AFTERNOON TEMPERATURES SOARING INTO THE MID 90S TO AROUND 100 WILL LEAD TO OVERNIGHT LOWS ONLY DROPPING INTO THE LOW/MID 70S. MAIN FOCUS FOR THE SHORT TERM IS ON THE POTENTIAL FOR THUNDERSTORMS TO DEVELOP ACROSS THE AREA ON THURSDAY. AS SURFACE LOW PRESSURE MOVES IN ACROSS WESTERN KANSAS TONIGHT BEHIND THE PASSING SURFACE HIGH...MODELS SHOW A WEAK BOUNDARY STRETCHING NORTHWARD INTO EASTERN NEBRASKA. COULD SEE SOME THUNDERSTORMS DEVELOP EARLY THURSDAY MORNING ACROSS EASTERN NEBRASKA NEAR THIS BOUNDARY WITH THE PRESENCE OF SOME WEAK CONVERGENCE AS WELL AS A STRONG THERMAL GRADIENT IN THAT REGION. UNCERTAINTY HOWEVER LIES IN THE TIMING OF THUNDERSTORM INITIATION AND WHETHER THIS ACTIVITY WILL BE ABLE TO SUSTAIN ITSELF INTO THE MORNING HOURS OR IF IT WILL WEAKEN THEN REDEVELOP NEAR THE BOUNDARY IN THE AFTERNOON. WITH THE BUILDING MID-LEVEL RIDGE...NORTHWESTERLY FLOW ALOFT WILL SHIFT ANY OF THIS ACTIVITY SOUTHEASTWARD INTO EASTERN KANSAS. MODELS SHOW VERY FAVORABLE CONDITIONS FOR ANY THUNDERSTORMS TO BECOME STRONG TO SEVERE...WITH 3500-5500J/KG OF MU CAPE...UPWARDS OF 45 TO 55 KTS OF 0-6KM BULK SHEAR AND STEEP LOW LEVEL LAPSE RATES GENERALLY GREATER THAN 7C/KM. MODEL SOUNDINGS SHOW CONDITIONS REMAINING CAPPED THROUGH EARLY AFTERNOON WITH THE CAP ERODING AWAY BY MID AFTERNOON. SO ANY ACTIVITY THAT DEVELOPS EARLIER IN THE DAY SHOULD REMAIN ELEVATED...BUT ONCE STORMS BECOME SURFACE BASED IN THE AFTERNOON THE CONDITIONS WILL BE PRIME FOR STRONG TO SEVERE THUNDERSTORMS. A THREAT FOR LARGE HAIL WILL BE POSSIBLE INITIALLY WITH ANY SURFACE BASED THUNDERSTORMS BUT SHOULD TRANSITION MORE OVER TO A SEVERE WIND THREAT AS THE LOW TO MID LEVEL JET INCREASES OVER THE AREA AND MODEL SOUNDINGS TAKE ON MORE OF A CLASSIC INVERTED V SHAPE. THE OTHER MAIN THREAT FOR THURSDAY IS THE EXTREME HEAT THAT IS EXPECTED. WITH SOUTH/SOUTHWESTERLY SURFACE WINDS DURING THE DAY...WARM NOSE LOOKS TO STRETCH INTO CENTRAL AND EASTERN KANSAS WITH 850MB TEMPERATURES PEAKING IN THE 25C-30C RANGE...ESPECIALLY ACROSS CENTRAL AND EAST CENTRAL KANSAS. WITH THESE CONDITIONS MIXING DOWN TO THE SURFACE...EXPECT AFTERNOON TEMPERATURES TO SOAR INTO THE MID/UPPER 90S ACROSS EAST CENTRAL KANSAS AND INTO THE LOW 100S OVER NORTH CENTRAL AND CENTRAL KANSAS. THE COOLEST CONDITIONS LOOK TO BE ACROSS FAR NORTHEAST KANSAS WHERE INCREASED CLOUD COVER FROM THE DEVELOPING THUNDERSTORMS SHOULD HINDER THE HEAT SOME WITH HIGHS STAYING IN THE LOWER 90S. CONDITIONS ARE ALSO EXPECTED TO BE QUITE HUMID AS DEWPOINT TEMPERATURES WILL LIKELY REMAIN IN THE UPPER 60S TO LOWER 70S...RESULTING IN HEAT INDICES REACHING UPWARDS OF 105F-108F DEGREES. AS A RESULT...A HEAT ADVISORY HAS BEEN ISSUED FOR MUCH OF NORTH CENTRAL...CENTRAL AND EAST CENTRAL KANSAS FOR THURSDAY AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 348 PM CDT WED JUN 26 2013 FCST FOCUS ON THE EXTENDED ON TEMPS AND PRECIP CHCS WITH SLOW EVOLUTION OF UPPER TROUGH. INITIAL COLD FRONT WILL SWEEP THROUGH THE AREA THU NIGHT. LLJ AND ASSOCIATED CONVERGENCE MAY LEAD TO CONTINUED ELEVATED STORM CHCS ACROSS SOUTHEAST HALF OF THE CWA SO WILL KEEP THUNDER CHCS OVERNIGHT ACROSS THAT AREA. BY FRI...HIGH PRESSURE WILL SWEEP HUMID AIR SOUTH AND EXPECT DEWPOINTS IN THE LOWER 60S ALONG WITH AIR TEMPERATURES IN THE UPPER 80S TO LOWER 90S. AS THE TROUGH CONTINUES TO DEEPEN HTS WILL LOWER AND AIR TEMPS WILL CONTINUE TO COOL THROUGH THE WEEKEND. BOTH ECMWF/GFS SUGGEST ENERGY SLIDING DOWN THE BACKSIDE OF THE UPPER TROUGH MAY BE SUFFICIENT TO FORCING DIURNAL PRECIP SUNDAY ACROSS THE EAST AND WILL LEAVE LOW CHC POPS IN THEN BUT FOR THE MOST PART ONCE WE GET THROUGH THURSDAY THE WEATHER LOOKS VERY COMFORTABLE AND MAINLY DRY WITH BELOW AVG TEMPS AND HUMIDITIES INTO NEXT WEEK. THE UPPER TROUGH MAY LINGER THROUGH NEXT WEEK SO NEAR OR BELOW AVG TEMPS COULD PERSIST THROUGH JULY 4TH && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1145 PM CDT WED JUN 26 2013 CONFIDENCE IN THE CONVECTIVE FORECAST FOR TOMORROW IS LOW. MODELS HAVE SHOWN LITTLE CONTINUITY WITH THE POSSIBILITY FOR ELEVATED NOCTURNAL STORMS. THE RAP AND HRRR IN PARTICULAR BRING ELEVATED STORMS FROM NEB INTO THE AREA EARLY IN THE DAY. IF THIS IS THE CASE...THERE COULD BE SCT STORMS THROUGH MUCH OF THE DAY. UNTIL ELEVATED STORMS BECOME APPARENT...THE FORECAST REMAINS CONSERVATIVE THINKING THE HIGHEST PROB FOR STORMS WILL BE DURING THE PEAK HEATING OF THE DAY. LOW LEVEL CONVERGENCE ALONG A WEAK SFC BOUNDARY AND A VERY UNSTABLE AIRMASS COULD LEAD TO EXPLOSIVE DEVELOPMENT IF MORNING SHOWERS AND THUNDERSTORMS DO NOT FORM. ANTICIPATE VFR CONDITIONS TO PREVAIL UNLESS CONVECTION MOVES OVER THE TERMINALS. && .TOP WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM 1 PM TO 8 PM CDT THURSDAY FOR KSZ008-009- 020>023-026-034>040-054>056-058-059. && $$ SHORT TERM...HENNECKE LONG TERM...OMITT AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
420 AM CDT THU JUN 27 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 415 AM CDT THU JUN 27 2013 WE FINALLY HAD A QUIET NIGHT ACROSS THE ENTIRE FORECAST AREA WITH THE REGIONAL RADAR SHOWING WEAK SHOWERS/STORMS BOTH SOUTH AND NORTH OF THE AREA. THERE IS A SURFACE LOW LOCATED NEAR LAKE WINNIPEG WITH A COLD FRONT STRETCHED OUT TO THE SOUTH ACROSS WESTERN MINNESOTA. THIS FRONT IS SLOWLY MOVING EAST WITH TIME AND IS LIKELY PLAYING A ROLE IN GENERATING THOSE THUNDERSTORMS IN THE DULUTH AREA. THERE IS ALSO SOME DRYING SHOWING UP IN WATER VAPOR IMAGERY IN NORTHERN MINNESOTA WHICH HIGHLIGHTS AN AREA OF PV MOVING E-SE WITH TIME. THOSE WIDESPREAD HIGH-BASED SHOWERS CRUISING ALONG AT 50 MPH ARE IN A ZONE OF DECENT 850-700MB FGEN. THE MERRIMAN PROFILER IN NORTH CENTRAL NE IS SHOWING 30 KT SOUTHWEST WINDS AT 700 MB AND THE WOOD LAKE PROFILER IN MN SHOWS NORTHWEST WINDS AT 35 KTS AT THE SAME LEVEL. THERE IS ALSO ABOUT A 5-7 C TEMPERATURE GRADIENT ACROSS THIS AREA. THIS AREA OF SHOWERS TO OUR SOUTH POSES LITTLE TO NO RAIN THREAT TO OUT AREA. HOWEVER...THE ADVANCING COLD FRONT AND THE POSITION OF THE UPPER JET SUGGESTS EASTERN PORTIONS OF THE FORECAST AREA COULD SEE A LITTLE RAIN TODAY. THIS IS MAINLY AN ISSUE FOR NORTHEAST MN...NORTHWEST WI AND AREAS TO THE SOUTHEAST OF THERE. THE BEST UPPER DIVERGENCE AND LEFT EXIT REGION REMAIN NORTH AND EAST OF THE FORECAST AREA AND MUCH OF THE CONVECTIVE ALLOWING MODELS DEVELOP ISOLATED-TO-SCATTERED SHOWERS IN WEST CENTRAL WI AND THEN MOVE THE ACTIVITY EAST WITH TIME. AS A RESULT...STILL HOLDING ON TO POPS MAINLY IN OUR WEST CENTRAL WI COUNTIES. THE GOOD NEWS IS...THE NORTHWEST FLOW WILL CONTINUE TO ADVECT DRIER AIR INTO MN/WI...SO THE THREAT FOR HEAVY RAIN AND FLOODING SHOULD BE LOW. THIS IS GOOD NEWS BECAUSE MOST OF THE AREA HAS SEEN ITS FAIR SHARE OF THE RAIN. KEAU REPORTED 1.80" OF RAIN WITH THOSE THUNDERSTORMS YESTERDAY. THE MPX RAOB ALREADY SHOWED A NICE DROP IN THE PWAT..FROM 1.61" AT 26.12Z TO 1.10" AT 27.00Z. WE DROPPED THE DEWPOINTS DOWN TODAY AND KEPT THE TEMPS WARM GIVEN THE LIKELIHOOD OF GOOD MIXING AND SUNSHINE. THE RAP/NAM BOTH INDICATE MIXING UP TO 800 MB AND USING SOME OF OUR MIX DOWN TOOLS..WE GET AFTERNOON DEWPOINTS IN THE 40S AND 50S. WE CERTAINLY DIDN`T GO 40S...BUT HAVE 50S IN THERE. SO...EVEN WITH THE COOLING AT 850 MB...WE SHOULD STILL WARM NICELY TODAY. FINALLY...PATCHY DENSE HAS FORMED THIS MORNING IN PORTIONS OF WEST CENTRAL WI...BUT THE EXTENT SHOULD NOT BE WIDESPREAD...SO WE DO NOT ANTICIPATE AN ADVISORY AT THIS POINT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 415 AM CDT THU JUN 27 2013 DETERMINISTIC SOLUTIONS REMAIN CONSISTENT ON DEEPENING AN UPPER TROUGH OVER THE EASTERN CONUS THROUGH THE UPCOMING WEEKEND. A STRONG SHORT WAVE WILL ROTATE SOUTHWARD ACROSS THE LOCAL AREA FROM LATE FRIDAY THROUGH SATURDAY CAUSING A PERIOD OF UNSETTLED WEATHER IN THE FORM OF SCATTERED SHOWERS AND THUNDERSTORMS. CHANCES FOR PRECIPITATION REMAIN HIGHEST ACROSS EASTERN MN AND WEST CENTRAL WI...WITH HIGH CHANCE TO LIKELY POPS IN PLACE. RAIN AMOUNTS DURING THE PERIOD SHOULD RUN FROM A FEW HUNDREDTHS TO A TENTH OF AN INCH FROM WEST TO EAST ACROSS THE MN CWA AND FROM A TENTH TO PERHAPS A QUARTER INCH OVER WEST CENTRAL WI. THERE WILL ALSO BE A COOL DOWN IN HIGH TEMPERATURE DURING THE WEEKEND AS NORTHERLY FLOW OCCURS. HIGHS BOTH SATURDAY AND SUNDAY WILL BE IN THE 70S. SUNDAY AND MONDAY ARE DRY WITH SMALL CHANCES FOR PRECIPITATION INCREASING ACROSS THE AREA FROM TUESDAY INTO WEDNESDAY. THIS CHANCE OF PRECIPITATION IS TIED TO AN UPPER LOW DEVELOPING IN THE EASTERN TROUGH AND THEN SLOWLY RETROGRADING TO THE CENTRAL PLAINS BY LATE NEXT WEEK. AT THIS TIME...LOW CHANCE POPS ARE MAINLY CONFINED TO WESTERN AND SOUTHERN MN. HIGHS EARLY NEXT WEEK WILL BE AT OR SLIGHTLY BELOW SEASONAL VALUES WITH MIDDLE 70S TO AROUND 80 FORECAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1111 CDT WED JUN 26 2013 COLD FRONT PUSHING INTO NW MN AS ISO-SCT STORMS WITH IT. BETTER CONVERGENCE AND INSTABILITY WITH THE FRONT IS BETTER ACROSS NRN MN...SO ANTICIPATE ANY STORMS TO REMAIN NORTH OF THE MPX TERMINALS TONIGHT...THOUGH ALL WILL SEE AN INCREASE IN CLOUD COVER. THIS CLOUD COVER WILL BE IMPORTANT FOR EAU CLAIRE AND FOG POTENTIAL... AS THE LESS CLOUD COVER THEY SEE...THE MORE FOG THERE WILL BE. FOR TOMORROW CU FIELD WILL GO FROM SCT-BKN EAST AND SKC WEST WITH NW WINDS BECOMING GUSTY. WILL BE A SHOWER POTENTIAL IN EAU CLAIRE DURING THE AFTERNOON...BUT SOUNDINGS FROM THE RAP/NAM SHOW LOTS OF DRY AIR OUT THERE TO OVERCOME...SO LEFT ANY PRECIP MENTION OUT. KMSP...HIGH CONFIDENCE IN ALL PARAMETERS THIS PERIOD. HRRR CONTINUES TO DEVELOP SOME SHOWERS BETWEEN 9Z AND 11Z...BUT HAVING A HARD TIME WHEN SEEING THE INSTABILITY FORECAST BY THE RAP TO STAY IN NRN MN THROUGH THE NIGHT. WINDS WILL BE FAIRLY LIGHT THROUGH THE NIGHT...BUT TUESDAY LOOKS TO BRING A GOOD MIXING DAY AND SOME NW WIND GUSTS TO AROUND 25 KTS. /OUTLOOK FOR KMSP/ FRI...VFR. CHC SHRA/TS WITH MVFR. WINDS NW AT 15G20 KTS. SAT...VFR. CHC SHRA/TS WITH MVFR. WINDS NNW AT 10-15 KTS. SUN...VFR. WINDS NE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...CLF LONG TERM...RAH AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1112 PM CDT WED JUN 26 2013 .UPDATE... 06Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 337 PM CDT WED JUN 26 2013 CLUSTERS OF SHOWERS AND THUNDERSTORMS HAVE ADVANCED EASTWARD INTO WISCONSIN THIS AFTERNOON...BUT AN OUTFLOW BOUNDARY EXISTS FROM ROUGHLY GOODHUE UP THROUGH THE TWIN CITIES METRO. WINDS HAVE VEERED WEST OF THIS BOUNDARY AND DEW POINTS HAVE FALLEN INTO THE 50S AND 60S. ASIDE FROM THE POSSIBILITY OF A COUPLE CELLS DEVELOPING ALONG THE OUTFLOW BOUNDARY AND THOSE ONGOING ACROSS WRN WI...NOT ANTICIPATING MUCH ELSE THIS EVENING. A SECONDARY FRONT WILL SAG SOUTH FROM NRN MN AND THE DAKOTAS WHICH COULD BE A FOCUS FOR ADDITIONAL ACTIVITY OVER CENTRAL MN AND NWRN WI OVERNIGHT. MUCAPE OF AROUND 1000 J/KG AND STRENGTHENING MID LEVEL SHEAR WILL SUPPORT A FEW STORMS...BUT THE THREAT SHOULD BE ISOLATED AND LIKELY NON-SEVERE. CYCLONIC FLOW WITH A DIGGING GREAT LAKES TROUGH COULD CONTINUE THE LOW CHANCE OF TSRA INTO THURSDAY OVER WRN WI. OTHERWISE...DRIER NORTHWEST FLOW AND 925 MB TEMPS OF +24C WILL ALLOW FOR ANOTHER WARM DAY IN THE MID/UPPER 80S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 337 PM CDT WED JUN 26 2013 THE OVERALL EVOLUTION OF THE UPPER LEVEL FLOW PATTERN IS THE MAIN PROBLEM IN THE LONG TERM. MOST DETERMINISTIC MODELS DROP SIGNIFICANT TROUGH OVER THE EASTERN CONUS DURING THE PERIOD. THE INITIAL SURGE OF FALLING HEIGHTS AND MOISTURE MOVES INTO THE REGION FRIDAY AND SATURDAY. THIS WILL SPREAD HIGH CHANCE POPS WEST AND SOUTH OVER THE AREA THROUGH THIS PERIOD. INSTABILITY ASSOCIATED WITH THIS FEATURE IS LIMITED AND WILL MENTION JUST ISOLATED THUNDER WITH THIS ACTIVITY. WITH MORE EXTENSIVE CLOUD COVER... TEMPERATURES SHOULD BE LIMITED TO THE 70S ON SATURDAY AS THE TROUGH MOVES THROUGH. FOR THE REMAINDER OF THE WEEKEND AND INTO EARLY NEXT WEEK...THE WESTERN CONUS RIDGE ON BOTH THE GFS AND ECMWF ARE INDICATING A GENERAL RETROGRESSION OF THE RIDGE...WITH ANOTHER STRONG WAVE RIDING THE EASTERN EDGE OF THIS RIDGE SOUTHWARD AND CARVING A DEEPER UPPER LOW PRESSURE AREA OVER THE CENTRAL CONUS. THIS SHOULD PROVIDE A RATHER COOL AND POSSIBLY INCREASINGLY WETTER PERIOD AS THE UPPER LOW SETTLES OVER THE AREA. THE CURRENT 8 TO 14 DAY FORECAST FOR THE AREA HAS COOLER AND DRIER CONDITIONS FOR THE AREA INTO THE EARLY PART OF NEXT MONTH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1111 CDT WED JUN 26 2013 COLD FRONT PUSHING INTO NW MN AS ISO-SCT STORMS WITH IT. BETTER CONVERGENCE AND INSTABILITY WITH THE FRONT IS BETTER ACROSS NRN MN...SO ANTICIPATE ANY STORMS TO REMAIN NORTH OF THE MPX TERMINALS TONIGHT...THOUGH ALL WILL SEE AN INCREASE IN CLOUD COVER. THIS CLOUD COVER WILL BE IMPORTANT FOR EAU CLAIRE AND FOG POTENTIAL... AS THE LESS CLOUD COVER THEY SEE...THE MORE FOG THERE WILL BE. FOR TOMORROW CU FIELD WILL GO FROM SCT-BKN EAST AND SKC WEST WITH NW WINDS BECOMING GUSTY. WILL BE A SHOWER POTENTIAL IN EAU CLAIRE DURING THE AFTERNOON...BUT SOUNDINGS FROM THE RAP/NAM SHOW LOTS OF DRY AIR OUT THERE TO OVERCOME...SO LEFT ANY PRECIP MENTION OUT. KMSP...HIGH CONFIDENCE IN ALL PARAMETERS THIS PERIOD. HRRR CONTINUES TO DEVELOP SOME SHOWERS BETWEEN 9Z AND 11Z...BUT HAVING A HARD TIME WHEN SEEING THE INSTABILITY FORECAST BY THE RAP TO STAY IN NRN MN THROUGH THE NIGHT. WINDS WILL BE FAIRLY LIGHT THROUGH THE NIGHT...BUT TUESDAY LOOKS TO BRING A GOOD MIXING DAY AND SOME NW WIND GUSTS TO AROUND 25 KTS. /OUTLOOK FOR KMSP/ FRI...VFR. CHC SHRA/TS WITH MVFR. WINDS NW AT 15G20 KTS. SAT...VFR. CHC SHRA/TS WITH MVFR. WINDS NNW AT 10-15 KTS. SUN...VFR. WINDS NE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...BORGHOFF LONG TERM...DWE AVIATION...MPG
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
332 AM CDT THU JUN 27 2013 .DISCUSSION... QUIET WEATHER WILL ONCE AGAIN BE INTERRUPTED BY NOCTURNAL/MORNING CONVECTION...WITH A CONTINUED CHANCE THROUGH THE DAY. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES A STRENGTHENING UPPER-LEVEL HIGH OVER THE DESERT SOUTHWEST...WITH 500MB HEIGHTS AS HIGH AS 5960M WITH WIDESPREAD 60-90M HEIGHT RISES ACROSS AREAS WEST OF THE ROCKIES. A SEASONALLY STRONG UPPER-LEVEL JET WAS IMPINGING ON THE PACIFIC NORTHWEST...WITH UP TO 130KT WINDS. BROAD 850MB LOW EXTENDED ACROSS THE ROCKIES...WITH RIDGING OVER THE CENTRAL PLAINS. A DRY POCKET WAS NOTED UNDER THE RIDGE...WITH 850MB DEWPOINTS OF -2C TO 2C IN EASTERN NEB/EASTERN KS/SOUTHEAST SD. HIGHER 850MB MOISTURE DID EXTEND FROM TX INTO THE HIGH PLAINS...AND RAP ANALYSIS INDICATED A STRENGTHENING LOW-LEVEL JET REACHING FROM THE HIGH PLAINS INTO SOUTHERN SD...WHERE HIGHER 850MB MOISTURE WAS POOLING. AN AREA OF SHOWERS WITH ISOLATED THUNDER HAS BLOSSOMED OVER CENTRAL/SOUTHEASTERN SD...WITH ECHOES JUST REACHING NORTH CENTRAL TO NORTHEAST NEB BUT NOT MUCH HITTING THE GROUND YET AT AREA OB SITES. MAIN FORECAST CONCERNS ARE SHOWERS/THUNDERSTORMS TODAY...FOLLOWED BY QUIET AND COOLER WEATHER. SHOWERS/ISOLATED THUNDER SHOULD CONTINUE TO FESTER ON THE NOSE OF THE LOW-LEVEL JET...AND SHOULD BE ABLE TO DROP INTO NORTHEAST NEB BY AROUND DAYBREAK AS MID-LEVEL RIDGE AND DRY AIR POCKET SLIDE EASTWARD...ALLOWING MOISTENING TO LOW LEVELS. NAM/RAP/HRRR FORECAST SOUNDINGS KEEP THE PROFILE RATHER STABLE THROUGH THE MORNING AROUND KOFK...SO AM THINKING CHARACTER OF THE ACTIVITY WILL REMAIN MORE IN THE SHOWERS/ISOLATED THUNDER CATEGORY THIS MORNING...RATHER THAN TURNING INTO SOMETHING MORE STORMY. STORMS SHOULD FESTER THROUGH THE DAY...THOUGH THEY MIGHT LOSE SOME COVERAGE NEAR MIDDAY AS 850MB LOW/BOUNDARY REORGANIZES. MEANWHILE...SOUTHEAST NEB SHOULD BE ABLE TO DESTABILIZE A GOOD PART OF THE DAY AHEAD OF THE SHOWERS. AS 850MB FRONT SAGS INTO SOUTHEAST NEB THIS AFTERNOON...WOULD EXPECT MORE OF A THUNDERSTORM MODE AS STORMS DEVELOP IN A MORE UNSTABLE ENVIRONMENT. BULK SHEAR ENVIRONMENT WOULD SUPPORT MORE ORGANIZED STORMS DOWN THERE...BUT STORM DEVELOPMENT REMAINS CONDITIONAL ON WHETHER THE SOUTHERN CWA REMAINS CLEAR LONG ENOUGH TO DESTABILIZE. IF IT DOES...COULD SEE A FEW STORMS REACH SEVERE LIMITS IN SOUTHEAST NEB...WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. STORMS WILL CONTINUE TO SLIDE SOUTH AND OUT OF THE AREA BY MID-EVENING. UPPER-LEVEL FLOW WILL BECOME NORTHWESTERLY TONIGHT/FRIDAY AS INTENSE UPPER-LEVEL RIDGE CONTINUES TO STRENGTHEN IN THE SOUTHWEST US. NORTHWESTERLY FLOW WILL BRING COOLER TEMPERATURES BUT LARGELY DRY WEATHER. MODELS DO INDICATE A SHORTWAVE ROTATING AROUND THE EASTERN US TROUGH ON SATURDAY THAT WOULD BRING SHOWERS INTO IOWA...BUT IT LOOKS LIKE THE CWA WILL REMAIN WEST OF THE PRECIP. THOUGH THE TIMING VARIES AMONG MODEL RUNS AND SOLUTIONS...LONG-RANGE MODELS ARE BECOMING MORE CONSISTENT IN INDICATING THAT THE EASTERN US UPPER- LEVEL TROUGH WILL RETROGRADE INTO THE CENTRAL PLAINS AND DEEPEN...POSSIBLY EVEN CUTTING OFF. DRY NORTHEASTERLY FLOW DOES NOT FAVOR MUCH PRECIPITATION...AND HAVE HELD PRECIP OUT OF THE FORECAST AT LEAST THROUGH TUESDAY. BEYOND THAT... MODEL BLENDS ARE FORCING MUCH HIGHER CHANCES THAN I WOULD CHOOSE TO INCLUDE GIVEN THE AMOUNT OF UNCERTAINTY AND POSSIBLITY FOR A DRY FETCH OF AIR...BUT LEFT THE CHANCES IN FOR COLLABORATION PURPOSES. DO NOT BELIEVE THAT TUESDAY NIGHT THROUGH THURSDAY WOULD BE A WASHOUT...DESPITE PROLONGED PERIOD OF PRECIP CHANCES...BUT COULD SEE PERIODS OF SHOWERS IF THE UPPER LOW DOES INDEED DEEPEN AND RETROGRADE OVER THE CENTRAL PLAINS. EITHER WAY...PATTERN WILL REMAIN COOLER THAN AVERAGE THROUGH NEXT WORK WEEK AND ENTERING THE HOLIDAY WEEKEND. MAYES && .AVIATION... 06Z TAFS FOR KOFK...KOMA AND KLNK. EXPECTING THE FIRST FEW HOURS OF THE TAF CYCLE TO BE FAIRLY QUIET WITH LIGHT AND VARIABLE SFC WINDS AND VFR CONDITIONS. THUNDERSTORMS ARE EXPECTED TO DEVELOP TO THE NORTHWEST OF THE TAF SITES AFTER 09Z AND ROLL SOUTHEAST THROUGHOUT THE MORNING HOURS. HAVE INCLUDED TEMPO GROUPS FOR ALL 3 SITES. KLNK MAY SEE THE STORMS LINGER THE LONGEST OVER THE MORNING AND POSSIBLY CONTINUE INTO THE AFTERNOON HOURS. KERN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
356 AM EDT THU JUN 27 2013 .SYNOPSIS... A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... RAIN IS ON THE WAY FOR WESTERN NEW YORK...BUT IT WILL TAKE ITS TIME. RADAR ALREADY SHOWS SHOWERS EXPANDING ACROSS OHIO WITH THIS AREA SLOWLY PUSHING TOWARD OUR REGION. RAIN WILL GRADUALLY SPREAD INTO WESTERN PORTIONS OF THE SOUTHERN TIER THROUGH MID- MORNING...THEN GRADUALLY INTO THE REST OF WESTERN NEW YORK THROUGH THIS EVENING. THE MAIN CAUSE OF THE PRECIPITATION WILL BE A SLOWLY APPROACHING UPPER LEVEL TROF. WATER VAPOR SHOWS THIS IS CURRENTLY AN OPEN WAVE AT AROUND 500 MB...BUT IT IS FORECAST TO CLOSE OFF AS IT MERGES WITH A LARGE UPPER LEVEL LOW THROUGH FRIDAY MORNING. WHILE MODEL GUIDANCE IS IN GENERAL AGREEMENT ON THIS PROGRESSION...IT IS STILL A TRICKY FORECAST GIVEN SUBTLE DIFFERENCES WHICH LEAD TO FAIRLY LARGE DIFFERENCES IN QPF FORECASTS. 00Z/06Z RUNS OF THE NAM...AND TO A LESSER EXTENT THE 00Z GFS/UKMET/EURO KEEP THE MAJORITY OF THE PRECIPITATION IN FAR SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE DAY. MEANWHILE THE RGEM AND SEVERAL HRRR RUNS ARE FURTHER NORTH...PERHAPS KEYING ON A SUBTLE SURFACE CONVERGENCE BOUNDARY SOUTH OF LAKE ONTARIO. RECALLING AN EVENT A WEEK AGO WHERE THE OUTLYING RGEM DID HAVE THE BEST HANDLE ON A SIMILAR SYSTEM...WILL CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE A BLEND OF BOTH CAMPS OF GUIDANCE. OVER THE NEXT FEW HOURS...RADAR TRENDS SHOULD HELP PIN THINGS DOWN. FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF. RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS (SREF/NAM/RGEM/GFS/EURO) IS FAIRLY CONSISTENT IN PUTTING THE STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES REGIONS FOR TONIGHT. A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON. WHILE QPFS ARE LESS ELSEWHERE...THERE STILL IS A POTENTIAL...ESPECIALLY CONSIDERING RAINFALL AMOUNTS IN EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL BUFFALO CREEKS TO BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES UP...AND BASED ON THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP THE TIMING FOR THE EASTERN LAKE ONTARIO SECTION OF THE WATCH. OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY CONDITIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE LOW LIFT VERY SLOWLY TO THE NORTH. ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE. THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL. ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY) WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW. IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE QUARTERS OF AN INCH OF RAIN ON FRIDAY. AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS AREA. REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM CONVECTION. SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE POSSIBILITY OF LIMITED SUNSHINE. EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT OF THE 60S DUE TO THE ANTICIPATED RAINFALL. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST PERIOD. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... 06Z TAFS...THE MAIN FORECAST CONCERN FOR THE REMAINDER OF THE OVERNIGHT PERIOD WILL BE THE POSSIBLE DEVELOPMENT OF RADIATION FOG. THE BEST CHANCE FOR FOG IS AT JHW...WITH A LESSER CHANCE FOR RADIATION FOG ELSEWHERE GIVEN LARGER TEMP/DEW POINT SPREADS. WILL CARRY IFR FOG IN JHW...WITH MVFR FOG AT ART. IN EACH CASE...PERIODS OF LOWER FOG ARE POSSIBLE AS VSBY IS LIKELY TO VARY. AFTER THIS...ATTENTION TURNS TO AN INCREASING CHANCE FOR SHOWERS TODAY AND TONIGHT. SOME OF THESE COULD BE FAIRLY HEAVY...WITH SOME EMBEDDED THUNDERSTORMS. GIVEN THE ISOLATED NATURE...AND UNCERTAINTY IN TIMING OF THE HEAVIEST SHOWERS...LARGELY KEEP THE TSTMS OUT OF THE TAF...WITH UPSTREAM CONDITIONS KEYING ANY POSSIBLE ADDITION OF TSTMS. AS WINDS BECOME MORE NE...AND AIR MOISTENS...EXPECT LOWERING CIGS AND VSBY THIS EVENING. OUTLOOK... FRIDAY...MVFR IN SHOWERS. SATURDAY THROUGH MONDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY EVENING FOR NYZ006>008. FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY AFTERNOON FOR NYZ001>005-010>014-019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...WOOD AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
330 AM CDT THU JUN 27 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT THU JUN 27 2013 SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM FOR TODAY. HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE. HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE. HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT. WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A CLEAR AND QUIET NIGHT EXPECTED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 330 AM CDT THU JUN 27 2013 NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST. MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20 KTS. AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT TO TIME AT THIS POINT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 330 AM CDT THU JUN 27 2013 VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF CYCLE ACROSS WESTERN AND CENTRAL NORTH DAKOTA. BREEZY NORTHWEST WINDS ARE EXPECTED DURING THE LATE MORNING THROUGH SUNSET...WITH GUSTS OF 20-25 KTS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AYD LONG TERM...JNS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
403 AM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL CONTINUE TO MOVE NORTHEAST OF THE OHIO VALLEY TODAY...WITH A LARGE UPPER LEVEL TROUGH OF LOW PRESSURE SITUATING ITSELF OVER THE EASTERN GREAT LAKES THROUGH THE WEEKEND. OCCASIONAL CHANCES OF SHOWERS AND THUNDERSTORMS WILL BE EXPECTED. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SHORTWAVE TROUGH IS CURRENTLY LOCATED OVER THE ILN CWA...AS A SURFACE LOW DEVELOPS UNDERNEATH. SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP AS A RESULT OF THESE FEATURES. IT HAS BEEN INTERESTING TO WATCH THE VARYING MOTIONS OF THESE SLOW-MOVING CONVECTIVE CLUSTERS...CAUGHT IN DIFFERENT AREAS OF FLOW AROUND THE TROUGH AND SURFACE LOW. OVERALL...AS THIS ENTIRE SYSTEM MOVES TO THE EAST...THE POPS WILL DECREASE FROM WEST TO EAST THROUGH THE MORNING HOURS (LEADING TO A DIURNAL LULL). THE LARGER-SCALE COMPUTER MODELS CONTINUE TO OVERDO PRECIPITATION NORTH OF THE OHIO RIVER ALL THE WAY INTO PENNSYLVANIA...WHILE ALSO STRUGGLING TO PICK UP ON THE SOUTHWARD-PROPAGATING CONVECTION IN THE TENNESSEE VALLEY. HRRR RUNS ARE ADAMANT IN KEEPING ANY THREAT OF HEAVY RAINFALL SOUTH AND EAST OF THE CWA...LEADING TO CONFIDENCE ENOUGH TO CLEAR OUT THE FLASH FLOOD WATCH. MOISTURE WILL NOT BE QUICK TO MOVE OUT TODAY...LEADING TO INCREASES IN THE SKY GRIDS AND DECREASES IN THE MAX TEMP FORECAST. CLEARING APPEARS MOST LIKELY IN THE SW CWA...WHERE HIGHS IN THE MID 80S ARE STILL BEING FORECAST. THE INFLUENCE OF THE TROUGH AND NW FLOW ALOFT WILL COOL TEMPS BY A FEW DEGREES AT HIGHER LEVELS...WHICH SHOULD ALLOW FOR SOME INSTABILITY (ESPECIALLY IN THE WESTERN CWA...PERHAPS AS HIGH AS 1500 J/KG BUT MORE LIKELY AROUND 1000 J/KG). THERE SHOULD ALSO BE ENOUGH LIFT WITH THE LARGE SCALE TROUGH STARTING TO ASSERT ITS INFLUENCE AFTER THE PASSAGE OF THE MORNING SHORTWAVE...WITH PRECIPITATION CHANCES SLIGHTLY FAVORED IN THE NE CWA (CLOSER TO THE DEEPER MOISTURE AND THE TROUGH). MIGHT BE JUST ENOUGH OF THE COMBINATION OF SHEAR AND INSTABILITY TO SUPPORT A FEW STRONG TO SEVERE STORMS...BUT THIS WOULD BE MORE OF A RANDOM CELLULAR CONVECTIVE EVENT...RATHER A THAN WELL-FORCED ORGANIZED SYSTEM. NOT A HUGE RISK...BUT WORTH A HEADS-UP IN THE HWO...AND THE SPC 5% LOOKS GOOD GIVEN THE CURRENT ASSESSMENT. NOT A BIG SPREAD IN TEMPS TODAY IN THE GUIDANCE...WITH THE FORECAST NEAR OR JUST BELOW THE CONSENSUS. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... HIGH-RES MODELS DEPICT THE DEVELOPMENT OF STRONG TO SEVERE THUNDERSTORMS OVER WISCONSIN TODAY...EVENTUALLY MOVING ON A SOUTHEASTERLY TRAJECTORY FROM THERE AFTER SUNSET. THERE MIGHT BE A LITTLE BIT OF SHORTWAVE ENERGY AS HEIGHT FALLS MOVE SE AT THE NOSE OF A 500MB NORTHWESTERLY JET...POINTING DOWN INTO THE SW ILN CWA DURING THE OVERNIGHT HOURS. AFTER RAMPING POPS DOWN DIURNALLY...HAVE SHOWN A SLIGHT INCREASE OVERNIGHT AGAIN. THERE APPEARS TO STILL BE ELEVATED INSTABILITY AVAILABLE...ALONG WITH INCREASING SHEAR THANKS TO THE JET. SO...IF THIS ACTIVITY DOES SURVIVE ALL THE WAY TO INDIANA AND OHIO...THERE COULD BE SOME HAIL ALONG WITH IT. THE SPECIFICS OF THE CONVECTIVE FORECAST BECOME MORE CONVOLUTED FROM FRIDAY THROUGH THE WEEKEND...AS THE LARGE SCALE UPPER TROUGH OVER SOUTHEASTERN CANADA GROWS AND RETROGRADES INTO THE OHIO VALLEY. SUCH A PATTERN IN THE SUMMER USUALLY SUPPORTS DAILY DIURNAL INSTABILITY (AIDED BY THE RELATIVE COOLER CONDITIONS ALOFT)...COMBINING WITH WHATEVER WEAK FORCING CAN COME THROUGH TO PROMOTE OCCASIONAL CONVECTIVE CHANCES. FRIDAY LOOKS SIMILAR TO THURSDAY...WITH OVERALL DIURNAL DEVELOPMENT...AND FAVORING THE NORTHEASTERN CWA FOR COVERAGE AGAIN. ON SATURDAY...A MUCH LARGER LOBE OF VORTICITY WILL ROTATE SOUTH THROUGH THE GREAT LAKES...PROMPTING A MUCH DIFFERENT SCENARIO IN THE FORECAST. POPS AND CLOUDS ARE BOTH ON THE INCREASE FOR SATURDAY (AND STARTING BOTH OF THESE ADJUSTMENTS RATHER EARLY IN THE NORTH)...ALONG WITH A DROP IN MAX TEMPS. THIS TROUGH WILL CLOSE OFF AS AN ELONGATED UPPER LOW OVER THE OHIO VALLEY ON SUNDAY. THE TROUGH WILL FORCE POPS THROUGH THE WEEKEND...WITH LIKELY POPS SATURDAY DURING THE DIURNAL PERIOD...AND HIGH CHANCE FOR SUNDAY. AFTER IT IS MORE CERTAIN WHERE THE TROUGH WILL CLOSE OFF ON SUNDAY...LIKELY POPS MAY ALSO BE NEEDED THERE...AS A SSW-TO-NNE AXIS OF MOISTURE AND FORCING WILL BE PRESENT. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... VERY UNSETTLED PATTERN TO DEVELOP AS AMPLIFIED LONGWAVE FLOW SETS UP AND PERSISTS THROUGH THIS PERIOD. COULDNT REALLY FIND A DECENT PERIOD TO INDICATE PROLONGED DRY CONDITIONS...WITH LONGWAVE TROUGH DEVELOPING/DEEPENING SW TO NE ALONG AND WEST OF THE APPALACHIAN CHAIN. TWO MASSIVE RIDGES...ONE OVER THE WEST CONUS AND ONE OVER THE ATLANTIC...RETROGRADE AND AMPLIFY THROUGH THE PERIOD WITH THE WEAKNESS/TROUGH BETWEEN THE TWO ALSO GAINING AMPLITUDE. NEGATIVE HEIGHT ANOMALIES ARE SIGNIFICANT AS THE TROUGH DEEPENS ESPECIALLY TO THE SOUTH OF THE OHIO VALLEY. SUCH A DEEP TROUGH IN THE HEART OF SUMMER MEANS THAT DAILY FLAREUPS OF CONVECTION ARE LIKELY...AND WILL BE ESPECIALLY LIKELY TIED TO WEAK WAVES MOVING THROUGH THE NWLY FLOW UNDERNEATH THE TROUGH EARLY IN THE PERIOD...AND IN THE SLY FLOW AHEAD OF THE TROUGH LATE IN THE PERIOD AS THE TROUGH AXIS DRIFTS TO THE WEST. LACK OF SCOURING OF THE LOW LEVEL MOISTURE FIELD MEANS THERE WILL BE PLENTY OF MOISTURE AND MARGINAL INSTBY FOR DAILY ROUNDS OF SCT STORMS TIED TO THE DIURNAL HEATING CYCLE. WAVES TO KEY ON /AT LEAST IN THE SHORT TERM/ ARRIVE BOTH FRIDAY AND SATURDAY SO THESE DAYS HAVE RELATIVELY HIGHER RAIN CHANCES...BUT THERE WILL LIKELY BE MANY MORE OF THESE WAVES INTO EARLY NEXT WEEK. TEMPERATURES...WHILE THEY WILL BE A BIT BELOW NORMAL...WON/T BE TOO COOL GIVEN THE CORE OF THE 850MB TEMP/500MB HEIGHT ANOMALIES QUICKLY DIG/RETROGRADE SOUTH AND WEST OF THE AREA. CERTAINLY NO 90S THE FORECAST...BUT A LONGER OF PERIOD OF UPPER 70S TO MID 80S AND RATHER DAMP/MUGGY CONDITIONS IS IN THE OFFING. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... WEAK LOW PRESSURE AND WEAK COLD FRONT WILL SLOWLY PUSH EAST THROUGH OUR REGION THIS MORNING. SOME FORCING IN THE UPPER LEVELS ON THE BACK SIDE OF THE WEAK LOW WILL CONTINUE THE THREAT FOR SHOWERS/ISOLATED THUNDERSTORMS NEAR THE NRN TAF SITES THROUGH 12Z. BIGGEST CONCERN THIS MORNING IS THE POTENTIAL FOR IFR CIGS. WITH ABUNDANT LOW LEVEL MOISTURE REMAINING ACROSS THE AREA...CIGS BELOW 1 KFT WERE ALREADY FORMING. BELIEVE THESE CIGS SHOULD SOLIDIFY INTO AN OVC DECK AS MID/UPPER LEVEL DEBRIS CLOUDS SHIFT EAST TOWARD SUNRISE WHICH WILL ALLOW FOR BETTER SATURATION. HAVE KEPT VSBYS IN THE MVFR RANGE...BUT SHOULD ENOUGH HIGHER CLOUDS THIN AND SHIFT TO THE EAST BEFORE SUNRISE...THESE MAY LOW TO IFR AS WELL SO WILL CONTINUE TO MONITOR. FOR THE DAY PERIOD...GREAT LAKES AND OHIO VALLEY REGION WILL REMAIN IN A NORTHWEST FLOW ALOFT...ALLOWING OCCASIONAL DISTURBANCES TO DROP INTO THE REGION THIS AFTERNOON AND OVERNIGHT. AS IFR CIGS RISE TO VFR BY EARLY/MID AFTERNOON...THE AIRMASS SHOULD DESTABILIZE FOR SOME SHOWER/THUNDERSTORM DEVELOPMENT. SOME MODELS SUGGEST THAT A SURFACE TROF AXIS MAY PROVIDE SOME LOW LEVEL FORCING AS WELL. THINK COVERAGE WILL BE IN THE 30 TO 40 PERCENT RANGE AND GIVEN THAT IT MAY BE DISORGANIZED...HAVE JUST USED THE VCTS/CB AT THE TAF SITES FROM 19Z TO 00Z. FOR THE OVERNIGHT...CANNOT RULE OUR SOME LINGERING SHOWER/THUNDERSTORM ACTIVITY GIVEN THE SYNOPTIC PATTERN...BUT DID NOT WANT TO HOLD ONTO VCTS/CB FOR MANY HOURS...SO WILL WAIT FOR LATER TAF ISSUANCES TO SEE IF THIS NEEDS TO CHANGE. OUTLOOK...THUNDERSTORMS POSSIBLE THROUGH MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...BINAU AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
319 AM CDT THU JUN 27 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 318 AM CDT THU JUN 27 2013 CURRENTLY SEEING SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP ACROSS SOUTH CENTRAL AND SOUTHEAST SOUTH DAKOTA. THESE APPEAR TO BE BASED ALONG AN AREA OF CONVERGENCE WAY UP AT 600 MB. THUS PROBABLY NOT MUCH IN THE WAY OF RAIN REACHING THE GROUND...ALTHOUGH A FEW HUNDRETHS OF AN INCH ARE POSSIBLE. CAPE ONLY AROUND 100-200 J/KG...THUS NOT EXPECTING THESE TO INTENSIFY MUCH...WITH JUST PERIODIC LIGHTNING STRIKES. MAY SEE ACTION INTENSIFY MORE TOWARDS THE MISSOURI RIVER CLOSER TO 10Z. AS THE LOW LEVEL JET CONTINUES TO INCREASE THIS REGION WILL BE IN A PRETTY GOOD AREA OF CONVERGENCE IN THE 700 TO 800 MB LAYER. BEING LOWER BASED THESE SHOWERS WILL HAVE A BIT MORE CAPE TO WORK WITH AND HAVE A BETTER CHANCE OF PRODUCING A PERIOD OF STEADY RAINFALL. HRRR SEEMS TO BE HANDLING THINGS PRETTY WELL...AND ALSO SUGGESTS COVERAGE AND INTENSITY OF THE STORMS SHOULD INCREASE AFTER 10Z IN THE MISSOURI RIVER CORRIDOR FROM BON HOMME COUNTY SOUTHEAST INTO PORTIONS OF NORTHWEST IOWA AND NORTHEAST NEBRASKA. CAPE WILL REMAIN TOO LOW FOR ANY SEVERE THREAT...BUT AN INCREASE IN LIGHTNING ACTIVITY AND BRIEF HEAVY RAIN SEEM PROBABLE. THIS ACTIVITY SHOULD DISSIPATE AND PUSH SOUTHEAST OF OUR CWA BY 18Z...GIVING WAY TO INCREASING SUNSHINE. HIGHS WILL BE PRETTY SIMILAR TO YESTERDAY...MAYBE A DEGREE OR TWO COOLER IN SPOTS...ESPECIALLY IF CLOUD CLOVER HANGS AROUND A BIT LONGER. BUT OVERALL...AN ABOVE NORMAL TEMPERATURE DAY WITH HIGHS IN THE MID 80S TO AROUND 90 EXPECTED. HUMIDITY LEVELS WILL ALSO BE PRETTY SIMILAR TO YESTERDAY...MAYBE A TOUCH LOWER BY AFTERNOON. WILL BE A BIT ON THE BREEZY SIDE BY AFTERNOON...ESPECIALLY ACROSS THE NORTHEAST HALF OF THE AREA...WITH WINDS GUSTING INTO THE 20 TO 30 MPH RANGE OUT OF THE NORTHWEST. EXPECTING CLEAR SKIES TONIGHT WITH A LIGHT NORTHWESTERLY BREEZE. LOWS SHOULD RUN A COUPLE DEGREES ABOVE AVERAGE...ABOUT 60 TO 65 ACROSS THE AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 318 AM CDT THU JUN 27 2013 FRIDAY LOOKS DRY...WARM AND WINDY WITH NORTHWEST WINDS AVERAGING ABOUT 20 TO 30 MPH IN THE EASTERN CWA. OTHERWISE EXPECTING HIGHS IN THE 80S. SATURDAY WILL SEE COOLER AIR CONTINUE TO WRAP INTO THE REGION AND SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE DURING PEAK HEATING. SOUNDING ANALYSIS SUGGESTS ONLY SKINNY CAPE...AND NOT MUCH OF IT...AVAILABLE FOR UPDRAFT STRENGTH SO NOT PLANNING ON SEVERE. LOOKS A BIT CAPPED IN THE WEST AS WELL SO WILL HAVE POPS MAINLY FROM INTERSTATE 29 EAST. WITH CLOUDS COMING IN LOWERED HIGHS A LITTLE...ESPECIALLY IN THE EAST WHERE 70 TO 75 WILL LIKELY BE THE MAX WHILE CENTRAL SOUTH DAKOTA COULD REACH 80. ANY CHANCE FOR SHOWERS SHOULD QUICKLY DIMINISH WITH PEAK HEATING SO NOT PLANNING ON ANYTHING IN THE EVENING. A GRADUAL DECREASE IN CLOUDS AND WIND WILL ALSO ALLOW FOR A COOL OVERNIGHT LOW...GENERALLY IN THE MID 50S. FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME...THE VARIOUS MODELS CONTINUE TO CONVERGE AND A COOL AND MOSTLY DRY WEATHER PATTERN. MODEL TRENDS FOR THE THIRD DAY ION A ROW PUSH THE RIDGE OVER THE ROCKIES EVEN FARTHER WEST WHILE A TROUGH OF LOW PRESSURE AND ASSOCIATED COOLER THERMAL FIELD SETTLE INTO THE PLAINS STATES...WHICH JUST A COUPLE OF DAYS AGO LOOKED LIKE WOULD BE OVER THE MIDWEST WITH THE PLAINS IN MORE OF A DRY MIXY PATTERN ON THE EDGE OF AN UPPER LEVEL RIDGE. OVERALL SUSPECT THAT HIGHS WILL BE IN THE 70S AND LOWS WILL BE IN THE 50S. PLEASANT WEATHER BUT A BIT ON THE COOL SIDE FOR THOSE LOOKING AT LAKE AND SWIMMING POOL ACTIVITIES. ONE PERIOD WITH THE POTENTIAL TO BE THE COOLEST AND POSSIBLY SEE SOME RAIN SHOWERS WILL BE WEDNESDAY WHERE BOTH THE GFS AND ECMWF SWING SOME UPPER LEVEL SUPPORT SOUTHWARD WITH INCREASING MID AND UPPER LEVEL MOISTURE. IF IT WERE TO CLOUD UP QUICKLY ON WEDNESDAY AND RAIN HIGH TEMPERATURES MAY BARELY CREEP INTO THE 70S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1026 PM CDT WED JUN 26 2013 PRIMARILY VFR CONDITIONS THROUGH THE TAF PERIOD...ALTHOUGH CONVECTION MAY DEVELOP THROUGH THE MISSOURI RIVER CORRIDOR AFTER 08Z...LINGERING INTO MID THURSDAY MORNING. KSUX IS ON THE EDGE OF THE BETTER CONVECTION CHANCES...SO DID NOT INCLUDE IN THE TAF AT THIS TIME. OTHERWISE...LIGHT AND VARIABLE WINDS THROUGH THE MID NIGHT TIME HOURS...THEN TRANSITIONING TO NORTHWESTERLY AND PICKING UP A BIT TOWARD THURSDAY MORNING WITH THE PASSAGE OF A BOUNDARY. OTHER THAN THE POSSIBILITY OF LINGERING CONVECTION IN THE LOWER MISSOURI RIVER CORRIDOR THROUGH AROUND 15Z...THE REMAINDER OF THURSDAY WILL HAVE A FEW MID CLOUDS WITH NORTHWESTERLY WINDS AVERAGING IN THE 10 TO 15 KT RANGE. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...08 AVIATION...JM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
212 AM CDT THU JUN 27 2013 .MESOSCALE UPDATE... LATEST H-TRIPLE-R 3KM RUN CONTINUES TO WEAKEN AND SINK LEADING EDGE OF CONVECTION SOUTHWARD INTO ALABAMA BY 08Z. EXPECT SOME ISOLATED TO SCATTERED CONVECTION WILL REMAIN ACROSS MIDDLE TENNESSEE THROUGH THE REMAINDER OF THE OVERNIGHT HOURS. NOT ANTICIPATING HAVING TO ISSUE WARNINGS BUT WILL CONTINUE TO MONITOR. BOYD && .PREV DISCUSSION... /ISSUED 1233 AM CDT THU JUN 27 2013/ MESOSCALE UPDATE... TWO SEPERATE MESO CONVECTIVE SYSTEMS DROPPING DOWN INTO THE NORTHERN PART OF THE TENNESSEE VALLEY AT THIS TIME WITH THE STRONGEST CONVECTION IN MID STATE CURRENTLY OVER WESTERN AREAS AND SPECIFICALLY IN HUMPHREYS COUNTY AT 0530Z. LATEST RUC RUN SHOWS 850 MBAR TROUGH DOWN THROUGH MIDDLE TENNESSEE JUST EAST OF INTERSTATE 65 SEPERATING THE TWO MCS`S. BOYD PREV DISCUSSION... /ISSUED 1207 AM CDT THU JUN 27 2013/ AVIATION 06Z DISCUSSION... SHORTWAVE WILL CONTINUE TO MOVE ACROSS THE MID STATE OVERNIGHT. AN AREA OF SHOWERS AND TSTMS WILL MOVE ACROSS NORTHERN AREAS AND TO THE SOUTH OF THE TAF SITES BY 10Z. TSTM REDEVELOPMENT WILL AGAIN BE POSSIBLE ACROSS EASTERN PORTIONS OF THE MID STATE AFT 18Z ON THU. HOWEVER...LESS COVERAGE CAN BE EXPECTED AS OVERALL...THE AIRMASS WILL BE DRIER. PREV DISCUSSION... /ISSUED 847 PM CDT WED JUN 26 2013/ MESOSCALE UPDATE...A COUPLE OF LINES OF STORMS BEING WATCHED. THE FIRST COMING DOWN INTO WEST KY APPEARS STRONG TO MARGINALLY SEVERE WITH 50-55 MPH WINDS EXPECTED BY THE PADUCAH OFFICE. THIS LINE OF STORMS SHOULD REACH OUR NORTHWEST COUNTIES ABOUT 10 PM. ANOTHER LINE OF STORMS ROUGHLY FROM EVANSVILLE TO LOUISVILLE LOOKS SEVERE. THIS LINE WILL DROP DOWN TO OUR NORTH CENTRAL AND NORTHEAST COUNTIES AROUND MIDNIGHT...AND MAY STILL BE PRODUCING SEVERE WINDS. THE EVENING SOUNDING SHOWS CAPES JUST OVER 2 KJ/KG. SHEAR AND WINDS INDICATE CONTINUED UPDRAFT SUPPORT FOR INCOMING STORMS. SOUTHWEST TO WEST LOW LEVEL JET SETTING UP WILL ADD SUPPORT FOR STORMS...ESPECIALLY INTO OUR NORTHEAST COUNTIES LATE TONIGHT. 13 PREV DISCUSSION... 627 PM CDT WED JUN 26 2013 MESOSCALE UPDATE...QUIET EVENING SO FAR IN MID TN AS WE WATCH CONVECTION EVOLVE A LITTLE MORE SLUGGISHLY THAN ANTICIPATED OVER THE OHIO VALLEY. NOT A LOT OF SEVERE REPORTS UP THERE YET...MORE HEAVY RAIN. HOWEVER...SHORT RANGE MODELS CONTINUE TO INDICATE MORE CONVECTIVE DEVELOPMENT OVER SOUTHERN IL AND SE MO...WITH ACTIVITY SINKING SOUTHWARD INTO MID TN AFTER 9 PM. ATMOSPHERE SHOULD BE PLENTY UNSTABLE AS THIS ACTIVITY MOVES IN WITH CAPES STILL AOA 2 KJ/KG. SO...OUR MAIN FOCUS FOR THE NEXT COUPLE OF HOURS WILL BE WATCHING THE EVOLUTION OF STORMS AND POTENTIAL MCS INTO WEST KY. ALSO...WE WILL GET NEW UPPER AIR RESULTS...WITH DATA BEING COLLECTED AT THIS TIME. 13 PREV DISCUSSION... /ISSUED 331 PM CDT WED JUN 26 2013/ DISCUSSION... UNSETTLED PATTERN IS EXPECTED FOR THE WEEK AHEAD WITH INCREASING H5 NORTHWEST FLOW THE NEXT FEW DAYS FOLLOWED BY A BROAD WESTWARD DRIFTING UPPER TROUGH EARLY NEXT WEEK. OVERALL...THIS PATTERN SHOULD CAUSE SOMEWHAT ABOVE AVERAGE CLOUD COVER AND RAIN CHANCES WITH SLIGHTLY BELOW AVERAGE MAX TEMPS FOR THIS TIME OF YEAR. H5 FLOW WILL BECOME MORE NORTHWESTERLY TONIGHT INTO SATURDAY AS SW U.S. RIDGE BUILDS AND EDGES WESTWARD...WHILE BROAD TROUGH DEVELOPS ACROSS THE GREAT LAKES. THIS OPENS THE DOOR FOR ORGANIZED STORMS TO APPROACH FROM THE NORTHWEST...ESPECIALLY TONIGHT WITH A POSSIBLE MCS. ALL AREAS WILL SEE AT LEAST A CHANCE FOR STORMS THIS EVENING BUT BEST COINCIDING MOISTURE LIFT AND INSTABILITY APPEAR TO ALIGN ACROSS THE NORTHEAST HALF OF MIDDLE TN LATE TONIGHT. UNSTABLE AIRMASS COMBINED WITH DECENT SHEAR COULD CAUSE SOME STRONG TO SEVERE STORMS OVERNIGHT. MORE STORMS POSSIBLE AGAIN THURSDAY/FRIDAY AS TWO MORE WEAK S/W APPROACH IN THE NW FLOW. THE NW FLOW PATTERN WILL ALSO ALLOW A COUPLE WEAK FRONTS/OUTFLOWS TO MOVE INTO MIDDLE TN THURSDAY AND FRIDAY. MODELS AGREE ON A BETTER SURGE ARRIVING SATURDAY...WITH THE FRONT MOVING THROUGH ALL OF MIDDLE TN THEN STALLING EAST OF OUR REGION ON SUNDAY. THIS SHOULD CAUSE MAX TEMPS TO BE A FEW DEGREES BELOW AVERAGE THIS WEEKEND. FOR SUNDAY NIGHT THROUGH WEDNESDAY...THE GREAT LAKES H5 LOW GRADUALLY SLIPS SOUTHWESTWARD TO THE OHIO VALLEY BY LATE SUNDAY...THEN FURTHER WEST TO THE MIDDLE OF THE U.S. BY NEXT WEDNESDAY. AT THE SURFACE...THE STALLED FRONT TO OUR SOUTHEAST WILL GRADUALLY SPREAD BACK TO THE WEST. EXPECT FRONT TO BE NEAR MIDDLE TN ON MONDAY THEN MOVE FURTHER WESTWARD TUE/WED. MEAN HUMIDITIES WILL INCREASE MONDAY THROUGH WEDNESDAY AS FLOW BECOMES MORE SOUTHERLY AT ALL LEVELS. THUS...EXPECT ABOVE AVERAGE CLOUD COVER AND CHANCES FOR AFTERNOON AND EVENING STORMS...WITH DAYTIME MAX TEMPS CONTINUING TO BE A BIT LOWER THAN AVERAGE. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1233 AM CDT THU JUN 27 2013 .MESOSCALE UPDATE... TWO SEPERATE MESO CONVECTIVE SYSTEMS DROPPING DOWN INTO THE NORTHERN PART OF THE TENNESSEE VALLEY AT THIS TIME WITH THE STRONGEST CONVECTION IN MID STATE CURRENTLY OVER WESTERN AREAS AND SPECIFICALLY IN HUMPHREYS COUNTY AT 0530Z. LATEST RUC RUN SHOWS 850 MBAR TROUGH DOWN THROUGH MIDDLE TENNESSEE JUST EAST OF INTERSTATE 65 SEPERATING THE TWO MCS`S. BOYD && .PREV DISCUSSION... /ISSUED 1207 AM CDT THU JUN 27 2013/ AVIATION 06Z DISCUSSION... SHORTWAVE WILL CONTINUE TO MOVE ACROSS THE MID STATE OVERNIGHT. AN AREA OF SHOWERS AND TSTMS WILL MOVE ACROSS NORTHERN AREAS AND TO THE SOUTH OF THE TAF SITES BY 10Z. TSTM REDEVELOPMENT WILL AGAIN BE POSSIBLE ACROSS EASTERN PORTIONS OF THE MID STATE AFT 18Z ON THU. HOWEVER...LESS COVERAGE CAN BE EXPECTED AS OVERALL...THE AIRMASS WILL BE DRIER. PREV DISCUSSION... /ISSUED 847 PM CDT WED JUN 26 2013/ MESOSCALE UPDATE...A COUPLE OF LINES OF STORMS BEING WATCHED. THE FIRST COMING DOWN INTO WEST KY APPEARS STRONG TO MARGINALLY SEVERE WITH 50-55 MPH WINDS EXPECTED BY THE PADUCAH OFFICE. THIS LINE OF STORMS SHOULD REACH OUR NORTHWEST COUNTIES ABOUT 10 PM. ANOTHER LINE OF STORMS ROUGHLY FROM EVANSVILLE TO LOUISVILLE LOOKS SEVERE. THIS LINE WILL DROP DOWN TO OUR NORTH CENTRAL AND NORTHEAST COUNTIES AROUND MIDNIGHT...AND MAY STILL BE PRODUCING SEVERE WINDS. THE EVENING SOUNDING SHOWS CAPES JUST OVER 2 KJ/KG. SHEAR AND WINDS INDICATE CONTINUED UPDRAFT SUPPORT FOR INCOMING STORMS. SOUTHWEST TO WEST LOW LEVEL JET SETTING UP WILL ADD SUPPORT FOR STORMS...ESPECIALLY INTO OUR NORTHEAST COUNTIES LATE TONIGHT. 13 PREV DISCUSSION... 627 PM CDT WED JUN 26 2013 MESOSCALE UPDATE...QUIET EVENING SO FAR IN MID TN AS WE WATCH CONVECTION EVOLVE A LITTLE MORE SLUGGISHLY THAN ANTICIPATED OVER THE OHIO VALLEY. NOT A LOT OF SEVERE REPORTS UP THERE YET...MORE HEAVY RAIN. HOWEVER...SHORT RANGE MODELS CONTINUE TO INDICATE MORE CONVECTIVE DEVELOPMENT OVER SOUTHERN IL AND SE MO...WITH ACTIVITY SINKING SOUTHWARD INTO MID TN AFTER 9 PM. ATMOSPHERE SHOULD BE PLENTY UNSTABLE AS THIS ACTIVITY MOVES IN WITH CAPES STILL AOA 2 KJ/KG. SO...OUR MAIN FOCUS FOR THE NEXT COUPLE OF HOURS WILL BE WATCHING THE EVOLUTION OF STORMS AND POTENTIAL MCS INTO WEST KY. ALSO...WE WILL GET NEW UPPER AIR RESULTS...WITH DATA BEING COLLECTED AT THIS TIME. 13 PREV DISCUSSION... /ISSUED 331 PM CDT WED JUN 26 2013/ DISCUSSION... UNSETTLED PATTERN IS EXPECTED FOR THE WEEK AHEAD WITH INCREASING H5 NORTHWEST FLOW THE NEXT FEW DAYS FOLLOWED BY A BROAD WESTWARD DRIFTING UPPER TROUGH EARLY NEXT WEEK. OVERALL...THIS PATTERN SHOULD CAUSE SOMEWHAT ABOVE AVERAGE CLOUD COVER AND RAIN CHANCES WITH SLIGHTLY BELOW AVERAGE MAX TEMPS FOR THIS TIME OF YEAR. H5 FLOW WILL BECOME MORE NORTHWESTERLY TONIGHT INTO SATURDAY AS SW U.S. RIDGE BUILDS AND EDGES WESTWARD...WHILE BROAD TROUGH DEVELOPS ACROSS THE GREAT LAKES. THIS OPENS THE DOOR FOR ORGANIZED STORMS TO APPROACH FROM THE NORTHWEST...ESPECIALLY TONIGHT WITH A POSSIBLE MCS. ALL AREAS WILL SEE AT LEAST A CHANCE FOR STORMS THIS EVENING BUT BEST COINCIDING MOISTURE LIFT AND INSTABILITY APPEAR TO ALIGN ACROSS THE NORTHEAST HALF OF MIDDLE TN LATE TONIGHT. UNSTABLE AIRMASS COMBINED WITH DECENT SHEAR COULD CAUSE SOME STRONG TO SEVERE STORMS OVERNIGHT. MORE STORMS POSSIBLE AGAIN THURSDAY/FRIDAY AS TWO MORE WEAK S/W APPROACH IN THE NW FLOW. THE NW FLOW PATTERN WILL ALSO ALLOW A COUPLE WEAK FRONTS/OUTFLOWS TO MOVE INTO MIDDLE TN THURSDAY AND FRIDAY. MODELS AGREE ON A BETTER SURGE ARRIVING SATURDAY...WITH THE FRONT MOVING THROUGH ALL OF MIDDLE TN THEN STALLING EAST OF OUR REGION ON SUNDAY. THIS SHOULD CAUSE MAX TEMPS TO BE A FEW DEGREES BELOW AVERAGE THIS WEEKEND. FOR SUNDAY NIGHT THROUGH WEDNESDAY...THE GREAT LAKES H5 LOW GRADUALLY SLIPS SOUTHWESTWARD TO THE OHIO VALLEY BY LATE SUNDAY...THEN FURTHER WEST TO THE MIDDLE OF THE U.S. BY NEXT WEDNESDAY. AT THE SURFACE...THE STALLED FRONT TO OUR SOUTHEAST WILL GRADUALLY SPREAD BACK TO THE WEST. EXPECT FRONT TO BE NEAR MIDDLE TN ON MONDAY THEN MOVE FURTHER WESTWARD TUE/WED. MEAN HUMIDITIES WILL INCREASE MONDAY THROUGH WEDNESDAY AS FLOW BECOMES MORE SOUTHERLY AT ALL LEVELS. THUS...EXPECT ABOVE AVERAGE CLOUD COVER AND CHANCES FOR AFTERNOON AND EVENING STORMS...WITH DAYTIME MAX TEMPS CONTINUING TO BE A BIT LOWER THAN AVERAGE. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 PM CDT WED JUN 26 2013 .SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT) ISSUED AT 231 PM CDT WED JUN 26 2013 SURFACE MAP THIS AFTERNOON HAS A COLD FRONT MOVING EAST ACROSS EASTERN MN/IA. RADAR SHOWING A BROKEN LINE OF THUNDERSTORMS //SOME FAIRLY INTENSE TO SEVERE AT TIMES// EXTENDING N-S ALONG THIS FRONTAL BOUNDARY. LITTLE 0-3KM BULK SHEAR NOTED SO MOST OF THESE STORMS ARE PULSE-TYPE IN NATURE WITH HIGHER-END RAP 0-1KM ML MUCAPE IN THE 3500-4200J/KG RANGE. THIS UNSTABLE AIR IS BEING PRODUCED BY TEMPERATURES ACROSS THE AREA IN THE 80-85 DEGREE RANGE AND DEW POINTS IN THE LOWER 70S. LOOK FOR THIS FRONT TO SLIP EAST INTO CENTRAL WI THIS EVENING... DRAGGING THE BULK OF THE SHOWERS/THUNDERSTORMS WITH IT. WITH PRECIPITABLE WATER VALUES STILL SITTING IN THE 1.5-1.8 INCH RANGE...ANY SHOWER/THUNDERSTORM EARLY THIS EVENING WILL BE CAPABLE OF TORRENTIAL DOWNPOURS WITH SOME LOCALIZED PONDING OF WATER POSSIBLE...ESPECIALLY ACROSS AREAS THAT RECEIVED PREVIOUS HEAVY RAIN AND HAVE ALREADY SATURATED SOILS. INTRODUCED A SLIGHT CHANCE OF SHOWER/THUNDERSTORMS MAINLY NORTH OF I-94 LATER OVERNIGHT//AFTER 09Z// AS A MID-LEVEL TROUGH AND LEFT EXIT REGION OF 75-100KT 300MB JET PUSHES INTO THIS AREA. MOST OF THIS ACTIVITY LOOKS ELEVATED/ACCAS TYPE IN NATURE. BUFKIT SHOWS DRYING IN THE LOWER LEVELS...SO NOT CONFIDENT ON HOW MUCH RAINFALL WILL ACTUALLY REACH THE SURFACE. THEREFORE...WILL KEEP POPS ON THE LOW SIDE FOR NOW. THIS MID-LEVEL WAVE CONTINUES TO MOVE ACROSS THE AREA ON THURSDAY FOR A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER. MAY HAVE TO WATCH THIS CONVECTION CLOSELY FOR SEVERE WIND/HAIL THREAT GIVEN STEEPER LAPSE RATES AND 0-6KM BULK SHEAR IN THE 35-45KT RANGE. THE GFS... WHICH IS THE DRIEST OF THE MODELS AS FAR AS DEW POINTS...YIELDS 0-1KM MLCAPE IN THE 1000-1500J/KG RANGE. IN ADDITION...MAY HAVE SOME ADDED LIFT DUE TO THE LEFT EXIT REGION OF 75-100KT 300MB JET. OTHERWISE...LOOKING FOR A HIGH IN THE LOWER/MIDDLE 80S WITH DEW POINTS IN THE MIDDLE 60S. LOOK FOR THE MID-LEVEL WAVE TO EXIT EAST OF THE REGION BY LATE THURSDAY EVENING...END THE THUNDERSTORM THREAT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 231 PM CDT WED JUN 26 2013 ON FRIDAY...MODELS IN GOOD AGREEMENT IN SWINGING A MID-LEVEL TROUGH SOUTHWESTWARD INTO THE AREA FROM THE GREAT LAKES REGION. STEEPENING LAPSE RATES WITH ASSOCIATED COLDER CYCLONIC FLOW ALOFT EXPECTED TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS MAINLY EAST OF THE MISSISSIPPI RIVER. OTHERWISE...PLAN ON HIGHS COOLING SOMEWHAT INTO THE MID 70S TO AROUND 80 WITH FAIRLY BREEZY NORTHWEST WINDS IN THE 10-20 MPH RANGE. LOOK FOR COOLER CONDITIONS WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORM ACTIVITY TO CONTINUE FRIDAY NIGHT THROUGH SATURDAY AS THE MID-LEVEL TROUGH SWINGS SOUTH THROUGH THE AREA. HIGHS ON SATURDAY WILL ACTUALLY SLIP SLIGHTLY BELOW NORMAL LEVELS IN THE LOW-MID 70S. APPEARS SHOWERS WILL BE EXITING THE AREA COMPLETELY BY SATURDAY EVENING AS THE TROUGH SHIFTS SOUTHEAST TOWARD THE OHIO RIVER VALLEY AND RIDGING BUILDS IN FROM THE NORTHWEST. FOR SUNDAY THROUGH WEDNESDAY...PLAN ON COOLER/OVERALL DRIER CONDITIONS AS A MAJOR MID-LEVEL TROUGH ESTABLISHES ITSELF OVER THE CENTRAL CONUS WITH A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS. EC REMAINS DRY DESPITE COOLER CYCLONIC FLOW AND THE GFS IS LIGHT AND SPOTTY WITH ITS QPF. LOOKS LIKE MAINLY SOME DAYTIME CUMULUS BUT REMAINING DRY. OTHERWISE...HIGHS ARE EXPECTED TO BE IN THE 75-80 DEGREE RANGE WITH OVERNIGHT LOWS MAINLY IN THE 50S...VERY PLEASANT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1150 PM CDT WED JUN 26 2013 THE MAIN FOCUS AT THE TAF SITES IS WITH THE POTENTIAL FOR VALLEY FOG AT LSE ALONG WITH WHETHER ANY PRECIPITATION WILL OCCUR. A COLD FRONT IS SLOWLY MOVING THROUGH THE REGION WITH DRIER AIR MOVING IN WITH IT. HOW FAST THIS DRIER AIR MOVES INTO LSE IS THE BIG QUESTION AS DEW POINT DEPRESSIONS REMAIN LOW AS OF MIDNIGHT. IF WINDS REMAIN LIGHT...EXPECT THAT SOME VALLEY FOG WILL BE POSSIBLE BY DAY BREAK. AS FAR AS THUNDERSTORMS GO...LSE WILL HAVE THE BEST CHANCES ON THURSDAY AFTERNOON BUT EXPECT THAT MUCH OF THE PRECIPITATION WILL END UP TO THE EAST OF IT. OVERALL...MAINLY EXPECT THAT CONDITIONS WILL BE VFR WITH WINDS SHIFTING TO THE NORTHWEST AND BECOMING GUSTY AT TIMES THURSDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1200 PM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT. && .NEAR TERM /THROUGH TONIGHT/... AT 14Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR SANDY HOOK WESTWARD NEAR RTE 80 THROUGH NNJ INTO NE PA. THAT COULD SERVE AS A FOCUS FOR LATE MORNING EARLY AFTN CONVECTION. OTRW THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED DOWN ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I LIKE THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS OVERALL DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY ACCURATE. POPS WILL BE FURTHER ADJUSTED DOWN FOR THIS AFTN EXCEPT DEL VALLEY WEST AND I 80 NORTH WHERE TSTMS WILL DEVELOP SOMETIME LATE TODAY OR THIS EVENING. THERE IS STILL A SMALL CHC OF CONVECTION IN S NJ/DE AROUND 18Z NEAR ANY CONVERGENCE ZONE BUT THE REAL DEAL ACTION WILL BE LATE IN THE DAY IN E PA/E/MD. THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD) HERE FOR THIS TIME OF YEAR. SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM FRIDAY OVER NE PA AND NNJ. FFG IS SO HIGH IN NE PA THAT NO FFA THERE. THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED. OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED G40-45KT. HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING. NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70. 930 AM UPDATE RAISED HOURLY TEMPS BY 2F AND WILL RAISE MAX A DEG OR 2 BY 1130AM. 12Z/27 ABERDEEN MD SOUNDING HAS A PWAT OF 1.71 KI 29 AND TT 43..SWEAT 177. MAX TT 88. MAX WIND LOWEST 20000 FT IS 25 KT. 12Z IAD SOUNDING ALSO A MAX T OF 88F WITH A KI 26 AND PWAT 1.57. MORE SWLY FLOW IN THAT SOUNDING AND A BIT MORE WIND. OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR 00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS. WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1415Z COSPA TRYING TO BUST OUT SCT CONVECTION DE BAY AROUND 19Z THEN SWEEP IT NNEWD THRU NJ THIS AFTN. MY CONFIDENCE ON THIS DE BAY NJ SOLN IS BELOW AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING. MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER THAN THE LESS RESOLVED NAM/GFS. LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE? THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS. LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION. THIS MORNING HAD SOME 1/4SM IN FAR NW NJ. EXPECTING A BIT OF THAT LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 930 AM UPDATE. && .SHORT TERM /FRIDAY/... THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY CUT IT TO 6 AM IN THE 1230 PM FCST UPDATE AS ITS DIFFICULT TO SEE ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE. DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID 30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA AREA. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND, WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST EACH DAY. A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF NEXT WEEK. WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND 1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR STRONG THUNDERSTORMS WITH HEAVY RAIN. WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...VFR SCT CLOUDS AOA 5000 FT (FEW 2000 FT AT 14Z SHOULD LIFT REFORM AOA 5000 BY 18Z) AND A GENERAL S-SW WIND G15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z. TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL EXPECTED AFTER 07Z MOST TAF LOCATIONS. FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT- BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER 20Z. OUTLOOK... FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND MORNING LOW CLOUDS/FOG. && .MARINE... SCA IS POSTED. WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 14Z SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY FOR AT LEAST ANOTHER WEEK ON THE WATERS. CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY ENTRANCE. SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT. OUTLOOK... THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER THE WEEKEND INTO EARLY NEXT WEEK. && .HYDROLOGY... AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY. WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES. IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY OCCUR DURING THE HEAVIEST DOWNPOURS. && .RIP CURRENTS... THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW JERSEY COAST TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW AND A BIT OF AN INCREASE IN THE SWELL PERIOD. IF THE SWELL IS ONLY 3 FT 6 SEC AT 18Z...AND THE WIND S 15KT WE WILL LOWER THE RISK TO LOW AND UPDATE THE SRF. AS IT STANDS WE ARE PROJECTING AT WORST A 4 FT 6 SEC SSE SWELL AT 18Z AND A S WIND 15 KT. EVEN THAT GIVES US A LOW RISK ON THE CUSP OF MDT. THE ONLY REASON AM NOT TAKING ACTION NOW IS THAT THE 14Z SLY WIND AT 44009 IS GUSTING 19KT. I`LL CHECK THIS AT 1545Z AND MAY DOWN GRADE THE RISK AT 16Z. NO MATTER...THERE IS RISK OF SIGNIFICANT RIP CURRENT FORMATION THIS AFTERNOON. FOR FRIDAY...WW3 IS PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND 15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL LOW-MDT FOR DE. A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC PERIOD. && .CLIMATE... WE`LL ADD MONTHLY CLI INFORMATION LATER TODAY AS TIME AVAILS. WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS... PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND 00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG TROF IN THE NE USA DAY 9-10 .. JULY 5-6 SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY COUNTRYSIDE. PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF 1GENERALLY TO 2 DEGREES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE NORMAL AT KACY. AS OF 6/26 PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL. THE JUNE 1981-2010 AVG IS 73.2. JUNE RAINFALL BELOW.. KILG ALREADY RECORD MONTHLY RFALL AT 10.09 KPHL RANKED #2 AT 8.81 INCHES BEHIND THE 10.06 JUNE 1998 RECORD. KACY RANKED #3 AT 7.20 BEHIND THE 7.57 IN 1935 AND RECORD JUNE TOTAL OF 8.45 IN 1920. KABE STILL RANKED 8TH WETTEST JUNE AT 6.48 INCHES. THE MONTHLY RECORD IS 10.51 IN 1938. WE MAY ADD DAILY RECORD RFALL TO THIS SECTION AT 330 PM FOR TODAY... FOR KRDG...KABE...KPHL...KILG. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY MORNING FOR NJZ001-007-008. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT FRIDAY FOR ANZ450>455. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON MARINE...DRAG/ROBERTSON HYDROLOGY... RIP CURRENTS... CLIMATE...1158A
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1030 AM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT. && .NEAR TERM /THROUGH TONIGHT/... AT 14Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR SANDY HOOK WESTWARD NEAR RTE 80 THROUGH NNJ INTO NE PA. THAT COULD SERVE AS A FOCUS FOR LATE MORNING EARLY AFTN CONVECTION. OTRW THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED DOWN ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I LIKE THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS OVERALL DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY ACCURATE. POPS WILL BE FURTHER ADJUSTED DOWN FOR THIS AFTN EXCEPT DEL VALLEY WEST AND I 80 NORTH WHERE TSTMS WILL DEVELOP SOMETIME LATE TODAY OR THIS EVENING. THERE IS STILL A SMALL CHC OF CONVECTION IN S NJ/DE AROUND 18Z NEAR ANY CONVERGENCE ZONE BUT THE REAL DEAL ACTION WILL BE LATE IN THE DAY IN E PA/E/MD. THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD) HERE FOR THIS TIME OF YEAR. SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM FRIDAY OVER NE PA AND NNJ. FFG IS SO HIGH IN NE PA THAT NO FFA THERE. THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED. OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED G40-45KT. HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING. NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70. 930 AM UPDATE RAISED HOURLY TEMPS BY 2F AND WILL RAISE MAX A DEG OR 2 BY 1130AM. 12Z/27 ABERDEEN MD SOUNDING HAS A PWAT OF 1.71 KI 29 AND TT 43..SWEAT 177. MAX TT 88. MAX WIND LOWEST 20000 FT IS 25 KT. 12Z IAD SOUNDING ALSO A MAX T OF 88F WITH A KI 26 AND PWAT 1.57. MORE SWLY FLOW IN THAT SOUNDING AND A BIT MORE WIND. OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR 00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS. WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1415Z COSPA TRYING TO BUST OUT SCT CONVECTION DE BAY AROUND 19Z THEN SWEEP IT NNEWD THRU NJ THIS AFTN. MY CONFIDENCE ON THIS DE BAY NJ SOLN IS BELOW AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING. MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER THAN THE LESS RESOLVED NAM/GFS. LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE? THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS. LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION. THIS MORNING HAD SOME 1/4SM IN FAR NW NJ. EXPECTING A BIT OF THAT LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 930 AM UPDATE. && .SHORT TERM /FRIDAY/... THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY CUT IT TO 6 AM IN THE 1230 PM FCST UPDATE AS ITS DIFFICULT TO SEE ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE. DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID 30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA AREA. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND, WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST EACH DAY. A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF NEXT WEEK. WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND 1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR STRONG THUNDERSTORMS WITH HEAVY RAIN. WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...VFR SCT CLOUDS AOA 5000 FT (FEW 2000 FT AT 14Z SHOULD LIFT REFORM AOA 5000 BY 18Z) AND A GENERAL S-SW WIND G15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z. TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL EXPECTED AFTER 07Z MOST TAF LOCATIONS. FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT- BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER 20Z. OUTLOOK... FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND MORNING LOW CLOUDS/FOG. && .MARINE... SCA IS POSTED. WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 14Z SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY FOR AT LEAST ANOTHER WEEK ON THE WATERS. CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY ENTRANCE. SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT. OUTLOOK... THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER THE WEEKEND INTO EARLY NEXT WEEK. && .HYDROLOGY... AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY. WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES. IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY OCCUR DURING THE HEAVIEST DOWNPOURS. && .RIP CURRENTS... THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW JERSEY COAST TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW AND A BIT OF AN INCREASE IN THE SWELL PERIOD. IF THE SWELL IS ONLY 3 FT 6 SEC AT 18Z...AND THE WIND S 15KT WE WILL LOWER THE RISK TO LOW AND UPDATE THE SRF. AS IT STANDS WE ARE PROJECTING AT WORST A 4 FT 6 SEC SSE SWELL AT 18Z AND A S WIND 15 KT. EVEN THAT GIVES US A LOW RISK ON THE CUSP OF MDT. THE ONLY REASON AM NOT TAKING ACTION NOW IS THAT THE 14Z SLY WIND AT 44009 IS GUSTING 19KT. I`LL CHECK THIS AT 1545Z AND MAY DOWN GRADE THE RISK AT 16Z. NO MATTER...THERE IS RISK OF SIGNIFICANT RIP CURRENT FORMATION THIS AFTERNOON. FOR FRIDAY...WW3 IS PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND 15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL LOW-MDT FOR DE. A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC PERIOD. && .CLIMATE... WE`LL ADD MONTHLY CLI INFORMATION LATER TODAY AS TIME AVAILS. WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS... PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND 00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG TROF IN THE NE USA DAY 9-10 .. JULY 5-6 SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY COUNTRYSIDE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY MORNING FOR NJZ001-007-008. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT FRIDAY FOR ANZ450>455. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG 1030 SHORT TERM...DRAG 1030 LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON 1030 MARINE...DRAG/ROBERTSON 1030 HYDROLOGY... RIP CURRENTS...1030 CLIMATE...1030
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
911 AM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT. && .NEAR TERM /THROUGH TONIGHT/... AT 12Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR SANDY HOOK WESTWARD TO PROBABLY NEAR RTE 80 IN NE PA. THAT COULD SERVE AS A FOCUS FOR LATE MORNING EARLY AFTN CONVECTION. THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE TODAY IS FOR ME A SIGNAL FOR SVR...POTENTIAL BIG SVR EVENING AS FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD) HERE FOR THIS TIME OF YEAR. SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM FRIDAY OVER NE PA AND NNJ. FFG IS SO HIGH IN NE PA THAT NO FFA THERE. THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED. OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED G40-45KT. HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING. NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70. THE 930 AM UPDATE WILL RAISE TEMPS AND DEWS TODAY BY 2F. 12Z/27 ABERDEEN MD SOUNDING HAS A PWAT OF 1.71 KI 29 AND TT 43..SWEAT 177. MAX TT 88. MAX WIND LOWEST 20000 FT IS 25 KT. 12Z IAD SOUNDING ALSO A MAX T OF 88F WITH A KI 26 AND PWAT 1.57. MORE SWLY FLOW IN THAT SOUNDING AND A BIT MORE WIND. OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR 00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS. WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER THAN THE LESS RESOLVED NAM/GFS. LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE? LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION. THIS MORNING HAD SOME 1/4SM IN FAR NW NJ. EXPECTING A BIT OF THAT LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 930 AM UPDATE. && .SHORT TERM /FRIDAY/... THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY CUT IT TO 6 AM IN THE 1230 PM FCST UPDATE AS ITS DIFFICULT TO SEE ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE. DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID 30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA AREA. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND, WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST EACH DAY. A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF NEXT WEEK. WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND 1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR STRONG THUNDERSTORMS WITH HEAVY RAIN. WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...LOCAL MVFR VSBY BECOME VFR SCT CLOUDS AOA 5000 FT AND A GENERAL S-SW WIND G10-15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z. TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL EXPECTED AFTER 07Z MOST TAF LOCATIONS. FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT- BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER 20Z. OUTLOOK... FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND MORNING LOW CLOUDS/FOG. && .MARINE... SCA IS POSTED. WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 12Z SWELL IS 2 FT 6 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY FOR AT LEAST ANOTHER WEEK ON THE WATERS. CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY ENTRANCE. SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT. OUTLOOK... THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER THE WEEKEND INTO EARLY NEXT WEEK. && .HYDROLOGY... AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY. WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES. IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY OCCUR DURING THE HEAVIEST DOWNPOURS. && .RIP CURRENTS... THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW JERSEY COAST TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW AND A BIT OF AN INCREASE IN THE SWELL PERIOD. IF THE SWELL IS ONLY 3 FT 6 SEC AT 18Z...AND THE WIND S 15KT WE WILL LOWER THE RISK TO LOW AND UPDATE THE SRF. AS IT STANDS WE ARE PROJECTING AT WORST A 4 FT 6 SEC SSE SWELL AT 18Z AND A S WIND 15 KT. EVEN THAT GIVES US A LOW RISK ON THE CUSP OF MDT. NO MATTER...THERE IS A RISK OF SIGNIFICANT RIP CURRENT FORMATION THIS AFTERNOON. FOR FRIDAY...WW3 IS PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND 15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL LOW-MDT FOR DE. A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC PERIOD. && .CLIMATE... WE`LL ADD MONTHLY CLI INFORMATION LATER TODAY AS TIME AVAILS. WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS...PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND 00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG TROF IN THE NE USA DAY 9-10 .. JULY 5-6 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY MORNING FOR NJZ001-007-008. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT FRIDAY FOR ANZ450>455. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG/GORSE 910 SHORT TERM...DRAG/GORSE 910 LONG TERM...ROBERTSON AVIATION...DRAG/GORSE/ROBERTSON 910 MARINE...DRAG/GORSE/ROBERTSON 910 HYDROLOGY... RIP CURRENTS...910 CLIMATE...910
AREA FORECAST DISCUSSION
NWS MIAMI FL
1032 AM EDT THU JUN 27 2013 .UPDATE... NO MAJOR CHANGES ARE PLANNED FOR THE MORNING UPDATES. RADAR SIGNATURES SHOWING SHOWERS/THUNDERSTORMS HAVE BEEN DEVELOPING OVER THE INTERIOR AND ALONG THE EAST COAST SEA BREEZE WITH STORM MOTION NEARLY STATIONARY AND THIS SHOWS UP WELL IN THE 12Z MFL SOUNDING WITH ERRATIC WIND DIRECTIONS UP THROUGH 20-25K FEET AT SPEEDS OF LESS THAN 5 KNOTS. THE POP GRIDS HAVE HANDLED THIS WELL. THE OVERALL TREND SHOULD BE THE ACTIVITY WILL TRANSITION TO MOVE TO THE INTERIOR AS THE AFTERNOON PROGRESSES WITH THE SEA BREEZES MOVING FARTHER INLAND. THE HRRR HAS HAD GOOD TIMING IN THE FORMATION OF THE CELLS BUT HAS BEEN TOO FAR SOUTH BUT STILL SHOWS MORE DEVELOPMENT FARTHER INLAND AFTER 17-18Z AND THIS SEEMS REASONABLE. KOB && .PREV DISCUSSION... /ISSUED 750 AM EDT THU JUN 27 2013/ AVIATION... SOUTHEASTERLY FLOW AROUND A BERMUDA HIGH WILL CONTINUE TODAY. THE HIGH IS WEAKENING SOME, SO FLOW SHOULD BE LIGHTER THAN YESTERDAY. WITH THIS FLOW, PLENTY OF MOISTURE WILL CONTINUE TO BE BROUGHT INTO SOUTH FLORIDA. THIS WILL BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE AREA TODAY. WITH THE LIGHTER FLOW, THE SPEED OF THE CONVECTIVE CELLS WILL BE SLOWER, WHICH WOULD ALLOW FOR MORE PRECIPITATION IN ONE LOCATION, WHICH COULD REDUCE VSBY FOR MORE THAN A BRIEF MOMENT, IF A CELL DEVELOPED IN VC OF A TAF SITE. CURRENTLY, JUST RANGE FROM VCSH THIS MORNING TO VCTS THIS AFTERNOON. THESE SHOULD ONCE AGAIN DIMINISH AFTER SUNSET THIS EVENING AND VFR SHOULD BR THE GENERAL RULE FOR MOST OF THE TAF PERIOD. PREV DISCUSSION... /ISSUED 420 AM EDT THU JUN 27 2013/ DISCUSSION... AN IMPRESSIVE RIDGE OF HIGH PRESSURE OVER THE FOUR CORNERS REGION WILL ALLOW FOR AN UNUSUALLY DEEP TROUGH TO DEVELOP OVER THE EASTERN CONUS INTO THE WEEKEND. THE TROUGH WILL DIG SOUTHWARD INTO THE SOUTHEAST ON FRIDAY AND INTO NORTH FLORIDA OVER THE WEEKEND. THE SURFACE RIDGE AXIS WILL PUSH SOUTHWARD TO NEAR LAKE OKEECHOBEE THIS AFTERNOON AND THEN SLIDE SOUTH OF THE REGION ON FRIDAY THROUGH THE WEEKEND. ISOLATED SHOWERS WERE BEGINNING TO DEVELOP OVER THE ATLANTIC AND ACROSS PALM BEACH COUNTY. HRRR AND OTHER HIGH RES MODELS INDICATE SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP VERY NEAR THE COAST ALONG THE SEA BREEZE THIS MORNING...WITH SCATTERED TO NUMEROUS SHOWERS AND STORMS DEVELOPING ACROSS THE INTERIOR AND WEST INTO THE AFTERNOON. WATERSPOUTS ARE POSSIBLE OVER THE ATLANTIC WATERS...MAINLY THIS MORNING. IN ADDITION...SLOW MOVING STORMS COULD LEAD TO LOCALIZED FLOODING ACROSS THE REGION. SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE EVENING HOURS ACROSS THE INTERIOR...WITH RAIN CHANCES SHIFTING TO THE COASTAL REGIONS OVERNIGHT. THE UPPER TROUGH OVER THE OHIO VALLEY WILL GET REINFORCED AND AMPLIFY FRIDAY INTO THE WEEKEND BY A SERIES OF SHORTWAVES ROTATING SOUTHWARD OUT OF CANADA. A MORE SOUTHERLY FLOW WILL DEVELOP ON FRIDAY AS THE UPPER LEVEL TROUGH DEEPENS INTO THE SOUTHEAST AND THE RIDGE PUSHES SOUTH AND EAST. PRECIPITABLE WATER VALUES WILL REMAIN NEAR 2 INCHES...AND WEAK STEERING FLOW WILL MAINTAIN A LOCALLY HEAVY RAINFALL THREAT ONCE AGAIN. SOUTH TO SOUTHWEST FLOW WILL THEN DEVELOP OVER THE WEEKEND WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY. THE UPPER LEVEL TROUGH WILL BEGIN TO RETROGRADE INTO THE MIDDLE OF THE NATION EARLY NEXT WEEK. THE FLOW WILL THEN SHIFT BACK TO THE SOUTHEAST. HOWEVER...DEEP MOISTURE WILL REMAIN ACROSS THE REGION...WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY. AVIATION... VFR CONDITIONS ARE EXPECTED FOR THIS MORNING FOR ALL TERMINALS. INCREASING MOISTURE BY DAYBREAK COULD TRIGGER A FEW SHOWERS OVER THE ATLANTIC COASTAL WATERS. WINDS TURN SOUTHEASTERLY TODAY AND MORE SOUTHERLY ON FRIDAY. KEPT VCSH FOR ALL TERMINALS STARTING AROUND 14Z. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER THE COASTAL WATERS AS THE DAY PROGRESSES WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS IN THE INTERIOR SECTIONS IN THE AFTERNOON AND EVENING. MARINE... BY FRIDAY AND INTO THE WEEKEND SOUTHERLY TO SOUTHWESTERLY WINDS MAINLY BELOW 15 KNOTS ARE FORECAST ACROSS THE REGIONAL WATERS WITH GULF AND ATLANTIC SEAS 3 FEET OR BELOW THROUGH THE FORECAST PERIOD. FIRE WEATHER... AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS THE PENINSULA THURSDAY AND FRIDAY AFTERNOONS AND EARLY EVENING. OTHERWISE NO OTHER FIRE WEATHER CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 76 89 78 / 50 30 60 40 FORT LAUDERDALE 89 78 89 75 / 50 30 50 30 MIAMI 90 77 89 77 / 50 30 40 30 NAPLES 90 74 88 76 / 40 20 40 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1020 AM EDT THU JUN 27 2013 .DISCUSSION... .UPDATE...CENTRAL FL SOUNDINGS SHOW 1.83 INCHES PRECIP WATER WITH CONVECTIVE ACTIVITY ALREADY DEVELOPING OVER PALM BEACH COUNTY SOUTH OF THE LOW LVL RIDGE AXIS NEAR LAKE OKEECHOBEE. 10Z CAPE SOUNDING INDICATES A BIT MORE WSW LOW LVL FLOW THAN MODEL PROGS SO EXPECT E COAST BRZ MAY BE DELAYED A BUT NORTH OF SEBASTIAN AND INCH IN MORE SLOWLY BREVARD COUNTY NORTHWARD. 12Z HRRR AND 00Z 4.5KM SPC WRF SCATTERED COVERAGE ALONG E COAST SEA BREEZE AND MOVING INTO THE INTERIOR LATER THIS AFTERNOON WITH E/W COAST SEA BREEZE INTERACTION OVER SEMINOLE/ORANGE COUNTIES INTO THE SRN INTERIOR BY LATE AFTERNOON. WNW/NW MID LAYER FLOW EXPECTED TO ALLOW SOME ACTIVITY TO TEND TO DRIFT BACK TOWARD THE COAST LATE IN THE BAY...ESPEC NORTH OF VRB. WITH THE SLIGHTLY STRONGER WSW LOW LVL FLOW AND WNW/NW STEERING FLOW FOR LATE DAY ACTIVITY...INCREASED POPS TO 50 PCT FOR CSTL SECTIONS FROM AROUND FORT PIERCE NORTHWARD. UPDATES AS WELL TO WIND GRIDS TO DELAY EAST COAST SEA BRZ TIMING JUST A BIT ACROSS CENTRAL/NRN CSTL ZONES. && .AVIATION...EXPECT ISOLD-SCT TSRA TO DVLP INITIALLY ALONG E COAST SEA BRZ FROM KMLB-KSUA BY 17Z...WITH SCT TSRA FOR INTERIOR TERMINALS AFT 19Z WITH INTERACTIONS OF E/W COAST SEA BREEZES OVER KSFB-KMCO 20Z-22Z TIME FRAME. STEERING FLOW MAY ALLOW SOME STORMS TO DRIFT BACK TWD THE COAST FROM KDAB-KTIX-KMLB IN THE EARLY EVENING. && .MARINE... MAIN ADJUSTMENT WAS TO LOWER SEAS TO AROUND 2 FT CSTL AND KEEP 2-3 FT OFFSHORE. WAVEWATCH/SWAN OVERFORECASTING BUOY 41009 THE LAST 12 HOURS. SOME LIGHTNING STORMS MAY MOVE BACK TWD THE COAST NORTH OF SEBASTIAN INLET LATER THIS AFTERNOON AND EARLY EVENING. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ VOLKMER/SEDLOCK
AREA FORECAST DISCUSSION
NWS MIAMI FL
750 AM EDT THU JUN 27 2013 .AVIATION... SOUTHEASTERLY FLOW AROUND A BERMUDA HIGH WILL CONTINUE TODAY. THE HIGH IS WEAKENING SOME, SO FLOW SHOULD BE LIGHTER THAN YESTERDAY. WITH THIS FLOW, PLENTY OF MOISTURE WILL CONTINUE TO BE BROUGHT INTO SOUTH FLORIDA. THIS WILL BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE AREA TODAY. WITH THE LIGHTER FLOW, THE SPEED OF THE CONVECTIVE CELLS WILL BE SLOWER, WHICH WOULD ALLOW FOR MORE PRECIPITATION IN ONE LOCATION, WHICH COULD REDUCE VSBY FOR MORE THAN A BRIEF MOMENT, IF A CELL DEVELOPED IN VC OF A TAF SITE. CURRENTLY, JUST RANGE FROM VCSH THIS MORNING TO VCTS THIS AFTERNOON. THESE SHOULD ONCE AGAIN DIMINISH AFTER SUNSET THIS EVENING AND VFR SHOULD BR THE GENERAL RULE FOR MOST OF THE TAF PERIOD. && .PREV DISCUSSION... /ISSUED 420 AM EDT THU JUN 27 2013/ DISCUSSION... AN IMPRESSIVE RIDGE OF HIGH PRESSURE OVER THE FOUR CORNERS REGION WILL ALLOW FOR AN UNUSUALLY DEEP TROUGH TO DEVELOP OVER THE EASTERN CONUS INTO THE WEEKEND. THE TROUGH WILL DIG SOUTHWARD INTO THE SOUTHEAST ON FRIDAY AND INTO NORTH FLORIDA OVER THE WEEKEND. THE SURFACE RIDGE AXIS WILL PUSH SOUTHWARD TO NEAR LAKE OKEECHOBEE THIS AFTERNOON AND THEN SLIDE SOUTH OF THE REGION ON FRIDAY THROUGH THE WEEKEND. ISOLATED SHOWERS WERE BEGINNING TO DEVELOP OVER THE ATLANTIC AND ACROSS PALM BEACH COUNTY. HRRR AND OTHER HIGH RES MODELS INDICATE SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP VERY NEAR THE COAST ALONG THE SEA BREEZE THIS MORNING...WITH SCATTERED TO NUMEROUS SHOWERS AND STORMS DEVELOPING ACROSS THE INTERIOR AND WEST INTO THE AFTERNOON. WATERSPOUTS ARE POSSIBLE OVER THE ATLANTIC WATERS...MAINLY THIS MORNING. IN ADDITION...SLOW MOVING STORMS COULD LEAD TO LOCALIZED FLOODING ACROSS THE REGION. SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE EVENING HOURS ACROSS THE INTERIOR...WITH RAIN CHANCES SHIFTING TO THE COASTAL REGIONS OVERNIGHT. THE UPPER TROUGH OVER THE OHIO VALLEY WILL GET REINFORCED AND AMPLIFY FRIDAY INTO THE WEEKEND BY A SERIES OF SHORTWAVES ROTATING SOUTHWARD OUT OF CANADA. A MORE SOUTHERLY FLOW WILL DEVELOP ON FRIDAY AS THE UPPER LEVEL TROUGH DEEPENS INTO THE SOUTHEAST AND THE RIDGE PUSHES SOUTH AND EAST. PRECIPITABLE WATER VALUES WILL REMAIN NEAR 2 INCHES...AND WEAK STEERING FLOW WILL MAINTAIN A LOCALLY HEAVY RAINFALL THREAT ONCE AGAIN. SOUTH TO SOUTHWEST FLOW WILL THEN DEVELOP OVER THE WEEKEND WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY. THE UPPER LEVEL TROUGH WILL BEGIN TO RETROGRADE INTO THE MIDDLE OF THE NATION EARLY NEXT WEEK. THE FLOW WILL THEN SHIFT BACK TO THE SOUTHEAST. HOWEVER...DEEP MOISTURE WILL REMAIN ACROSS THE REGION...WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY. AVIATION... VFR CONDITIONS ARE EXPECTED FOR THIS MORNING FOR ALL TERMINALS. INCREASING MOISTURE BY DAYBREAK COULD TRIGGER A FEW SHOWERS OVER THE ATLANTIC COASTAL WATERS. WINDS TURN SOUTHEASTERLY TODAY AND MORE SOUTHERLY ON FRIDAY. KEPT VCSH FOR ALL TERMINALS STARTING AROUND 14Z. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER THE COASTAL WATERS AS THE DAY PROGRESSES WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS IN THE INTERIOR SECTIONS IN THE AFTERNOON AND EVENING. MARINE... BY FRIDAY AND INTO THE WEEKEND SOUTHERLY TO SOUTHWESTERLY WINDS MAINLY BELOW 15 KNOTS ARE FORECAST ACROSS THE REGIONAL WATERS WITH GULF AND ATLANTIC SEAS 3 FEET OR BELOW THROUGH THE FORECAST PERIOD. FIRE WEATHER... AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS THE PENINSULA THURSDAY AND FRIDAY AFTERNOONS AND EARLY EVENING. OTHERWISE NO OTHER FIRE WEATHER CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 76 89 78 / 50 30 60 40 FORT LAUDERDALE 89 78 89 75 / 50 30 50 30 MIAMI 90 77 89 77 / 50 30 40 30 NAPLES 90 74 88 76 / 40 20 40 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...84/AK AVIATION/RADAR...71/JE
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1121 AM EDT THU JUN 27 2013 .UPDATE... MAIN UPDATE THIS MORNING IS TO POPS TO CATCH MORE NEAR TERM TRENDS. HAD SOME STRONGER STORMS THIS MORNING ACROSS NE AL THAT SHIFTED INTO NW GA THIS MORNING BUT HAVE ALSO HAD ADDITIONAL DEVELOPMENT NORTH AND EAST OF THIS LINE. FORTUNATELY...THIS AREA OF STRONGER STORMS HAS WEAKENED FOR NOW. OVERALL THINKING IS TOWARD THE TRENDS OF THE HRRR. LINE OF STORMS ACROSS NORTH GEORGIA WILL CONTINUE TO SINK SOUTHWARD INTO THE AFTERNOON BUT EXPECT BOTH DEVELOPMENT AHEAD OF AND BEHIND THIS LINE ACROSS BOTH NORTH AND CENTRAL GEORGIA. MODIFIED 12Z FFC SOUNDING FOR THE EXPECTED CONDITIONS ACROSS CENTRAL GEORGIA THIS AFTERNOON SHOWS AROUND 4000 J/KG OF CAPE...SO EXPECTING PLENTY OF INSTABILITY THIS AFTERNOON. WITH THIS...SEVERE STORMS ARE STILL POSSIBLE THIS AFTERNOON WITH THE MAIN THREATS BEING DAMAGING WIND AND HAIL. 11 && .PREV DISCUSSION... SHORT TERM.../TODAY AND TONIGHT/ /ISSUED 351 AM EDT THU JUN 27 2013/ OVER THE LAST FEW HOURS LARGE THUNDERSTORM COMPLEX OVER THE TN VALLEY HAS MOVED INTO NORTHERN AL AND WESTERN NC. ONLY A FEW SHOWERS/ISO THUNDERSTORMS HAVE MADE IT INTO NORTHERN GA. THE HRRR HAS A VERY GOOD HANDLE ON THE SYSTEM. IR IMAGERY SHOWS COPIOUS AMOUNTS OF CLOUD DEBRIS SPREADING INTO NORTHERN GA THIS MORNING. IF THE CLOUD COVER HOLDS...THIS MAY HELP LIMIT INSTABILITY ACROSS THE NORTHERN ZONES. HRRR IS HINTING THAT THE COMPLEX WILL LAY OUT AN OUTFLOW BOUNDARY ACROSS NORTH GA THIS MORNING. THIS SCENARIO SEEMS REASONABLE AND EXPECT LATE MORNING/AFT THUNDERSTORMS TO FILL IN ACROSS THE SOUTHERN TWO THIRDS OF THE FORECAST AREA AS THE ATMOS DESTABILIZES. STORMS WILL HAVE THE POTENTIAL TO BECOME SEVERE...WITH DAMAGING WIND GUSTS AND LARGE HAIL POSSIBLE. IN ADDITION...WITH PWATS AOA 2 INCHES...LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE. EXPECT CONVECTION TO DIMINISH IN THE EVENING WITH THE LOSS OF HEATING. EXACTLY WHERE CONVECTION WILL DEVELOP THIS AFTERNOON WILL HEAVILY DEPEND UPON WHERE THE OUTFLOW BOUNDARY SETS UP. IN ADDITION...THICKER CLOUD COVER TO THE NORTH COULD HELP LIMIT THUNDERSTORM DEVELOPMENT. HAVE PLACED THE HIGHEST POPS IN THE NORTH FOR THE FIRST PART OF THE DAY. MAY HAVE TO MAKE SOME ALTERATIONS LATER THIS MORNING...DEPENDING UPON IF ANY OF THE SHOWERS OVER NORTHERN GA MAKE IT DOWN TO THE METRO. THE HIGHEST POPS SHOULD BE SOUTH OF THE METRO AREA DURING THE LATE AFTERNOON AND EARLY EVENING. NLISTEMAA LONG TERM /FRIDAY THROUGH WEDNESDAY/... /ISSUED 351 AM EDT THU JUN 27 2013/ FRIDAY BEGINS WITH ONE WAVE OF SHORTWAVE ENERGY EXITING OFF THE SE ATLANTIC COAST WHILE A SECOND SYSTEM LOOKS POISED TO DROP THROUGH THE TENNESSEE VALLEY AND INTO THE LOCAL AREA FRIDAY AFTERNOON. AT THIS TIME...INSTABILITY LOOKS TO BE ADEQUATE FOR NUMEROUS THUNDERSTORMS TO DEVELOP BUT LESS THAN PREVIOUS DAYS VALUES AND WITH LIMITED SHEAR VALUES IN PLACE...ONLY ISOLATED SEVERE STORMS WITH THIS COMPLEX ARE EXPECTED AT THIS TIME. WITH SURFACE TROUGH AXIS AND CONTINUED IMPULSES ROTATING THROUGH THE BASE OF THE TROUGH...POPS WILL REMAIN HIGHER THAN CLIMO THROUGH THE OVERNIGHT PERIOD AND HAVE REFLECTED THIS TREND IN THE LATEST GRID SET. MAIN MOISTURE AXIS WILL SHIFT SOUTH FOR SATURDAY BUT ADDITIONAL STRONG IMPULSE WILL MOVE ON THE DOORSTEP OF NORTH GA BY LATE EVENING. WILL KEEP HIGHEST POPS WHERE BETTER MOISTURE IS WITH LIKELY TO THE SOUTH BUT WILL GO HIGHER THAN GUIDANCE FOR THE NORTH GIVEN BETTER UPPER SUPPORT. THE ACTUAL UPPER LOW WHICH WILL HAVE BEEN A SEMI PERMANENT FEATURE BY THIS POINT WILL FINALLY ROTATE SOUTHWARD SATURDAY NIGHT INTO SUNDAY. AGAIN...BETTER MOISTURE REMAINS OVER EXTREME SOUTHERN SECTIONS OF THE FORECAST AREA AND HAVE GONE LIKELY THERE AGAIN ALTHOUGH WENT HIGHER THAN GUIDANCE NORTH AGAIN WITH UPPER LOW. THROUGH THE REMAINDER OF THE PERIOD...UPPER LOW WEAKENS AND RETROGRADES WITH LESS UPPER SUPPORT. DESPITE THIS...SOUTHEAST FLOW TO BRING COPIOUS AMOUNTS OF MOISTURE TO THE AREA RESULTING IN POPS ABOVE CLIMO. THIS WILL ALSO KEEP TEMPS BELOW CLIMO FOR THE REMAINDER OF THE LONG TERM PERIOD AS WELL. DEESE AVIATION... 12Z UPDATE... /ISSUED 734 AM EDT THU JUN 27 2013/ MADE A FEW CHANGES TO THE TAF FOR THE 12Z UPDATE. FOLLOWED THE 05Z HRRR FAIRLY CLOSELY. EXPECT EARLIER THUNDERSTORM COMPLEX ACROSS THE TN VALLEY TO LAY DOWN AN OUTFLOW BOUNDARY LATER THIS MORNING. CONVECTION IS EXPECTED TO FIRE ALONG THE BOUNDARY DURING THE LATE MORNING/EARLY AFTERNOON HOURS. CONVECTIVE DEVELOPMENT WILL DEPEND HEAVILY ON WHERE THE OUTFLOW BOUNDARY SETS UP AND ANY DIFFERENTIAL HEATING BOUNDARIES. TAF MAY HAVE TO BE ADJUSTED AT LATER ISSUANCES IF CONVECTION DEVELOPS BEHIND THE INITIAL OUTFLOW BOUNDARY. //ATL CONFIDENCE...12Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 88 71 94 69 / 60 50 60 60 ATLANTA 87 72 91 71 / 60 40 60 60 BLAIRSVILLE 81 67 84 64 / 30 30 60 30 CARTERSVILLE 87 71 93 68 / 60 30 60 60 COLUMBUS 90 73 94 73 / 60 50 50 60 GAINESVILLE 86 70 90 69 / 60 30 60 60 MACON 89 72 94 72 / 60 50 50 60 ROME 89 71 94 67 / 60 30 60 40 PEACHTREE CITY 87 71 93 69 / 60 50 60 60 VIDALIA 90 74 93 75 / 60 60 50 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...11 SHORT TERM...NLISTEMAA LONG TERM....DEESE AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
903 AM CDT THU JUN 27 2013 .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING. * INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON. KREIN //DISCUSSION...UPDATED 12Z... FOG HAS DEVELOPED OVERNIGHT ACROSS MUCH OF NORTHERN ILLINOIS AND NORTHWEST INDIANA...BUT SHOULD DISSIPATE BY 13Z AS THE SUN BEGINS TO HEAT THE SURFACE. NORTHWEST WINDS WILL ALSO GRADUALLY INCREASE AROUND THIS TIME WITH A FEW GUSTS INTO THE MID TEENS POSSIBLE THIS AFTERNOON AS WE MIX DEEPLY. THUNDERSTORMS LOOK LIKELY AGAIN TODAY AS THE ATMOSPHERE QUICKLY BECOMES UNSTABLE. BY 16-17Z FORECAST SOUNDINGS INDICATE SURFACE BASED PARCELS WILL BE UNCAPPED...BUT THE BETTER FORCING APPEARS TO ARRIVE LATER IN THE AFTERNOON AS A MID LEVEL DISTURBANCE AND UPPER LEVEL JET BEGIN TO MOVE OVER THE AREA. THUNDERSTORMS ARE EXPECTED TO BECOME STRONG TO SEVERE BUT SHOULD BE SCATTERED IN COVERAGE. THE ONLY SIGNIFICANT FOCUS AT THE SURFACE WOULD BE A LAKE BREEZE THAT IS EXPECTED TO STAY EAST OF THE CHICAGO TERMINALS. THE THUNDERSTORM THREAT SHOULD FADE NOT TOO LONG AFTER SUNSET WITH QUIET CONDITIONS EXPECTED OVERNIGHT. MODEST NORTHWEST FLOW SHOULD INHIBIT FOG FROM DEVELOPING OVERNIGHT. ON FRIDAY...WINDS WILL BE A LITTLE STRONGER OUT OF THE NORTHWEST WITH GUSTS TO AROUND 20 KT POSSIBLE. THERE WILL BE ADDITIONAL CHANCES FOR THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING AT SOME POINT THURSDAY AFTERNOON BUT DUE TO SCATTERED COVERAGE LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 304 AM CDT EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND. WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY THROUGH SUNDAY. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
641 AM CDT THU JUN 27 2013 .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * FOG/BR DISSIPATING EARLY THURSDAY MORNING. * THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING. * INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON. BMD //DISCUSSION...UPDATED 12Z... FOG HAS DEVELOPED OVERNIGHT ACROSS MUCH OF NORTHERN ILLINOIS AND NORTHWEST INDIANA...BUT SHOULD DISSIPATE BY 13Z AS THE SUN BEGINS TO HEAT THE SURFACE. NORTHWEST WINDS WILL ALSO GRADUALLY INCREASE AROUND THIS TIME WITH A FEW GUSTS INTO THE MID TEENS POSSIBLE THIS AFTERNOON AS WE MIX DEEPLY. THUNDERSTORMS LOOK LIKELY AGAIN TODAY AS THE ATMOSPHERE QUICKLY BECOMES UNSTABLE. BY 16-17Z FORECAST SOUNDINGS INDICATE SURFACE BASED PARCELS WILL BE UNCAPPED...BUT THE BETTER FORCING APPEARS TO ARRIVE LATER IN THE AFTERNOON AS A MID LEVEL DISTURBANCE AND UPPER LEVEL JET BEGIN TO MOVE OVER THE AREA. THUNDERSTORMS ARE EXPECTED TO BECOME STRONG TO SEVERE BUT SHOULD BE SCATTERED IN COVERAGE. THE ONLY SIGNIFICANT FOCUS AT THE SURFACE WOULD BE A LAKE BREEZE THAT IS EXPECTED TO STAY EAST OF THE CHICAGO TERMINALS. THE THUNDERSTORM THREAT SHOULD FADE NOT TOO LONG AFTER SUNSET WITH QUIET CONDITIONS EXPECTED OVERNIGHT. MODEST NORTHWEST FLOW SHOULD INHIBIT FOG FROM DEVELOPING OVERNIGHT. ON FRIDAY...WINDS WILL BE A LITTLE STRONGER OUT OF THE NORTHWEST WITH GUSTS TO AROUND 20 KT POSSIBLE. THERE WILL BE ADDITIONAL CHANCES FOR THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN VSBY IMPROVING TO VFR BY 12-13Z. * MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING AT SOME POINT THURSDAY AFTERNOON BUT DUE TO SCATTERED COVERAGE LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. BMD //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 304 AM CDT EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND. WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY THROUGH SUNDAY. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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 QUAD CITIES IA IL
1009 AM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 957 AM CDT THU JUN 27 2013 12Z SOUNDING SHOWS A RESPECTABLE SFC CAP IN PLACE WITH A CONVECTIVE TEMPERATURE IN THE LOWER 90S. 12Z UA ANALYSIS COMBINED WITH THE MCS AND LIFT TOOLS HELP EXPLAIN THE CURRENT CONVECTION IN THE PLAINS. THE CONVECTION IN SOUTHEAST NEBRASKA IS DRIVEN BY A SMALL SHORTWAVE AND IS RUNNING ALONG THE 850MB MOISTURE GRADIENT. FURTHER NORTH FROM SOUTH DAKOTA INTO NORTHWEST IOWA THERE IS NICE CONVERGENCE IN THE 800-750MB LAYER WITH A THETA E GRADIENT PRESENT. OVERALL FORCING WHEN USED WITH THE MCS AND LIFT TOOLS INDICATE DRY CONDITIONS WILL REMAIN IN PLACE ACROSS THE CWFA DURING THE MORNING HOURS WITH DOWNWARD MOTION ACROSS THE AREA. THE SOUTH DAKOTA/NORTHWEST IOWA CONVECTION WILL SLOWLY DISSIPATE AS IT MOVES INTO DRIER AIR AND THE CONVERGENCE MOVES SOUTH AND EAST. THE MCS/LIFT TOOLS SHOW THE 800-750MB CONVERGENCE MOVING SOUTHEAST AND ENTERING THE FAR SOUTHWEST/SOUTH PARTS OF THE CWFA SHORTLY AFTER MID DAY. HOWEVER...THE THETA E GRADIENT IS VERY WEAK. FCST SOUNDINGS OFF THE RAP SUGGEST CONVECTIVE TEMPERATURES REMAINING AT 90 OR ABOVE BUT SHOW OVERALL LIFT INCREASING DURING THE AFTERNOON AS A VORT MAX MOVES THROUGH. THUS DIURNAL CLOUDS WILL DEVELOP. IF THE RAP TRENDS ON CONVECTIVE TEMPERATURE ARE CORRECT...THE POTENTIAL EXISTS FOR VERY LITTLE IN THE WAY OF AFTERNOON CONVECTION. TRENDS WILL HAVE TO BE MONITORED BUT POPS HAVE BEEN PULLED BACK TO THE FAR SOUTHWEST/SOUTH AND FAR NORTHEAST FOR ISOLATED TO SCATTERED CONVECTION. ..08.. && .SYNOPSIS... ISSUED AT 340 AM CDT THU JUN 27 2013 STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT POPPED UP OVER NW IL THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT THU JUN 27 2013 MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO MAKE IT THIS FAR EAST. A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE SCATTERED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 340 AM CDT THU JUN 27 2013 INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION. THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN. SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 613 AM CDT THU JUN 27 2013 AN AREA OF THUNDERSTORMS OVER EASTERN NEBRASKA AND SOUTH DAKOTA IS EXPECTED TO WEAKEN AS IT MOVES SOUTHEAST ACROSS INTO SOUTHERN IOWA AND WESTERN ILLINOIS TODAY. A SECOND AREA OF SCATTERED THUNDERSTORMS IS EXPECTED TO DEVELOP OVER NORTHERN ILLINOIS THIS AFTERNOON. OUTSIDE OF THUNDERSTORMS...VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...DMD SHORT TERM...DMD LONG TERM...14 AVIATION...DMD
AREA FORECAST DISCUSSION
NWS DES MOINES IA
649 AM CDT THU JUN 27 2013 ...UPDATED AVIATION DISCUSSION... .SHORT TERM.../TODAY/... ISSUED AT 357 AM CDT THU JUN 27 2013 WEAK SHORTWAVE WILL CONTINUE TO CUT ACROSS EASTERN SD INTO EASTERN NE AND WESTERN IA THIS MORNING. THE HI-RES MODELS KEEP THE PRECIP CONFINED TO THE SOUTHWEST PORTIONS OF THE FORECAST AREA EXCEPT THE 06Z HRRR WHERE ITS FURTHER EAST AND IS A BIT MORE BULLISH WITH THE COVERAGE. LITTLE MOISTURE AND FORCING WITH THIS SYSTEM AND ANYTHING THAT DEVELOPS WILL BE HIGH BASED AND SO LEANED TOWARD THE HIRES-NMM MODEL RUNS AS IT SEEMED TO HAVE THE BEST SOLUTION WRT TO LOCATION AND TIMING OF PRECIP. CURRENT RADAR TRENDS HAVE THE PRECIP MOVING INTO THE WESTERN FORECAST AREA BY AROUND 10Z OR SHORTLY AFTER AND LOOK TO BE MORE SOUTHEAST. HOWEVER...THE LATEST RAP CORFIDI VECTORS AND STORM MOTION VECTORS SHIFT THE PRECIP MOVEMENT MORE SOUTHERLY AS IT MOVES EAST. HIGH TEMPS TODAY SHOULD BE FAIRLY SIMILAR TO WEDNESDAY...MAYBE SLIGHTLY COOLER OVER THE WEST TO SOUTH WHERE THE PRECIP AND MORE CLOUD COVER WILL BE THIS MORNING. WAS CONFIDENT ENOUGH TO GO ABOVE GUIDANCE FOR HIGHS TODAY. .LONG TERM.../TONIGHT THROUGH WEDNESDAY/... ISSUED AT 357 AM CDT THU JUN 27 2013 NO SIGNIFICANT CONCERNS THROUGH THIS PERIOD BUT WITH DEFINITE PATTERN CHANGE COMING. MCS MAY BE LINGERING OVER SRN IA AT 00Z WITH THERMODYNAMIC FORCING JUST EXITING INTO MO. THIS WILL LEAD TO FAIR WEATHER LATER THU NIGHT AND INTO EARLY FRI AS LONG WAVE PATTERN BEGINS TO AMPLIFY INTO WRN CONUS TROUGH/ERN RIDGE. HOWEVER BY FRI AFTERNOON REMNANTS OF CURRENT COMPACT MANITOBA SHORT WAVE WILL BEGIN DROPPING INTO WRN SIDE OF GREAT LAKES MEAN TROUGH. THIS WILL GRADUALLY INCREASE SUB 3KM MOISTURE NE-SW...AND COUPLED WITH DAYTIME HEATING...PRODUCE WEAK BUT UNCAPPED SEVERAL HUNDRED MLCAPES. THIS WILL LIKELY DEVELOP SCATTERED UNORGANIZED WEAK PEAK HEATING CONVECTION NE...WHICH IS DEPICTED IN NAM AND HI RES MODEL SIMULATED REFLECTIVITY. LATE DAY MIXING PRODUCING THE INSTABILITY WILL ALSO LIKELY ALLOW BRISK NW WINDS TO MIX DOWN AS SLP GRADIENT INCREASES WITH GUSTS AT OR ABOVE 30 MPH POSSIBLE CENTRAL AND NORTH. BY SATURDAY...THERE IS LITTLE EVIDENCE OF ANY QG FORCING AS AFOREMENTIONED VORT AXIS DROPS THROUGH MS VALLEY. MAIN RESULT WILL BE INCREASED DEEP MOISTURE WITH SOUNDINGS SHOWING NEAR SATURATION AT MANY SITES. THIS ENVIRONMENT WILL LIKELY PRODUCE AREAS OF LIGHT SHOWERS INTO SAT...POSSIBLY LINGERING INTO THE SE EARLY EVENING. HAVE RAISED POPS FURTHER THROUGH THE CHANCE CATEGORY. COULD SEE SOME THUNDER BUT NOTHING SEVERE ANTICIPATED. THE LONG WAVE PATTERN WILL CHANGE LITTLE TO END THE WEEKEND WITH PERSISTENT WEST/EAST TROUGH/RIDGE BUT WITH WEAKENING FLOW. SOME RETROGRESSION WILL EVEN OCCUR BY EARLY NEXT WEEK WITH TROUGH EVENTUALLY DRIFTING WWD INTO MS VALLEY. MID/LOWER TROPOSPHERIC FLOW WILL BE RATHER WEAK IN THIS TIME FRAME WITH LITTLE FORCING. THERE IS SOME POTENTIAL FOR PRECIP...BUT CONFIDENCE IN TIMING OR LOCATION IS NOT GREAT ENOUGH TO INCLUDE MENTION AT THE MOMENT. HOWEVER BY LATE TUE INTO WED TROUGH AND ASSOCIATED FORCING INCREASES SLIGHTLY WHICH JUSTIFIES LOW CHANCES BY THAT TIME. TEMPERATURE WISE...READINGS WILL BE BELOW NORMAL WITH CORRESPONDINGLY LOWER DEWPOINTS. FRIDAY COULD VERY WELL BE THE LAST DAY WE EXCEED 80F FOR THE DURATION OF THE PERIOD AREA WIDE. IN FACT GFS/ECMWF H85 TEMP TIME SERIES THROUGH THE FOLLOWING WEEKEND /JUL 6/ SHOWS LITTLE EVIDENCE OF ANY RETURN TO WARM AND HUMID WEATHER. && .AVIATION...27/12Z ISSUED AT 648 AM CDT THU JUN 27 2013 VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH SOME MID TO HIGH LEVEL CLOUDS ACROSS SOUTHWEST IOWA AS A SHORTWAVE MOVES THROUGH EASTERN NEBRASKA. SOME MIXING EXPECTED TO AND CONTINUED WITH GUSTS IN THE UPPER TEENS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...SMALL AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
619 AM CDT THU JUN 27 2013 .SYNOPSIS... ISSUED AT 340 AM CDT THU JUN 27 2013 STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT POPPED UP OVER NW IL THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT THU JUN 27 2013 MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO MAKE IT THIS FAR EAST. A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE SCATTERED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 340 AM CDT THU JUN 27 2013 INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION. THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN. SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 613 AM CDT THU JUN 27 2013 AN AREA OF THUNDERSTORMS OVER EASTERN NEBRASKA AND SOUTH DAKOTA IS EXPECTED TO WEAKEN AS IT MOVES SOUTHEAST ACROSS INTO SOUTHERN IOWA AND WESTERN ILLINOIS TODAY. A SECOND AREA OF SCATTERED THUNDERSTORMS IS EXPECTED TO DEVELOP OVER NORTHERN ILLINOIS THIS AFTERNOON. OUTSIDE OF THUNDERSTORMS...VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...DMD SHORT TERM...DMD LONG TERM...14 AVIATION...DMD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
605 AM CDT THU JUN 27 2013 .AVIATION... 12Z TAFS FOR KOMA...KLNK...KOFK. SCATTERED TSTMS SHOULD AFFECT THE TAF SITES...WITH TEMPORARY MVFR CONDITIONS POSSIBLE. KEPT MENTION OF TSRA AT KOFK UNTIL MID DAY...BUT INTO MID AFTN AT KOMA AND KLNK. SOME STORMS MAY PRODUCE GUSTY WINDS...SO DID INCLUDE MENTION OF THAT. LATER TODAY AND INTO TONIGHT...EXPECT VFR CONDITIONS AND FAIRLY LIGHT WINDS. MODELS SHOW SOME MOISTURE AROUND 8000 FEET LATE TONIGHT...BUT DID NOT ADD ANOTHER GROUP FOR THAT AT THIS POINT. MILLER && .PREV DISCUSSION... /ISSUED 332 AM CDT THU JUN 27 2013/ DISCUSSION... QUIET WEATHER WILL ONCE AGAIN BE INTERRUPTED BY NOCTURNAL/MORNING CONVECTION...WITH A CONTINUED CHANCE THROUGH THE DAY. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES A STRENGTHENING UPPER-LEVEL HIGH OVER THE DESERT SOUTHWEST...WITH 500MB HEIGHTS AS HIGH AS 5960M WITH WIDESPREAD 60-90M HEIGHT RISES ACROSS AREAS WEST OF THE ROCKIES. A SEASONALLY STRONG UPPER-LEVEL JET WAS IMPINGING ON THE PACIFIC NORTHWEST...WITH UP TO 130KT WINDS. BROAD 850MB LOW EXTENDED ACROSS THE ROCKIES...WITH RIDGING OVER THE CENTRAL PLAINS. A DRY POCKET WAS NOTED UNDER THE RIDGE...WITH 850MB DEWPOINTS OF -2C TO 2C IN EASTERN NEB/EASTERN KS/SOUTHEAST SD. HIGHER 850MB MOISTURE DID EXTEND FROM TX INTO THE HIGH PLAINS...AND RAP ANALYSIS INDICATED A STRENGTHENING LOW-LEVEL JET REACHING FROM THE HIGH PLAINS INTO SOUTHERN SD...WHERE HIGHER 850MB MOISTURE WAS POOLING. AN AREA OF SHOWERS WITH ISOLATED THUNDER HAS BLOSSOMED OVER CENTRAL/SOUTHEASTERN SD...WITH ECHOES JUST REACHING NORTH CENTRAL TO NORTHEAST NEB BUT NOT MUCH HITTING THE GROUND YET AT AREA OB SITES. MAIN FORECAST CONCERNS ARE SHOWERS/THUNDERSTORMS TODAY...FOLLOWED BY QUIET AND COOLER WEATHER. SHOWERS/ISOLATED THUNDER SHOULD CONTINUE TO FESTER ON THE NOSE OF THE LOW-LEVEL JET...AND SHOULD BE ABLE TO DROP INTO NORTHEAST NEB BY AROUND DAYBREAK AS MID-LEVEL RIDGE AND DRY AIR POCKET SLIDE EASTWARD...ALLOWING MOISTENING TO LOW LEVELS. NAM/RAP/HRRR FORECAST SOUNDINGS KEEP THE PROFILE RATHER STABLE THROUGH THE MORNING AROUND KOFK...SO AM THINKING CHARACTER OF THE ACTIVITY WILL REMAIN MORE IN THE SHOWERS/ISOLATED THUNDER CATEGORY THIS MORNING...RATHER THAN TURNING INTO SOMETHING MORE STORMY. STORMS SHOULD FESTER THROUGH THE DAY...THOUGH THEY MIGHT LOSE SOME COVERAGE NEAR MIDDAY AS 850MB LOW/BOUNDARY REORGANIZES. MEANWHILE...SOUTHEAST NEB SHOULD BE ABLE TO DESTABILIZE A GOOD PART OF THE DAY AHEAD OF THE SHOWERS. AS 850MB FRONT SAGS INTO SOUTHEAST NEB THIS AFTERNOON...WOULD EXPECT MORE OF A THUNDERSTORM MODE AS STORMS DEVELOP IN A MORE UNSTABLE ENVIRONMENT. BULK SHEAR ENVIRONMENT WOULD SUPPORT MORE ORGANIZED STORMS DOWN THERE...BUT STORM DEVELOPMENT REMAINS CONDITIONAL ON WHETHER THE SOUTHERN CWA REMAINS CLEAR LONG ENOUGH TO DESTABILIZE. IF IT DOES...COULD SEE A FEW STORMS REACH SEVERE LIMITS IN SOUTHEAST NEB...WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. STORMS WILL CONTINUE TO SLIDE SOUTH AND OUT OF THE AREA BY MID-EVENING. UPPER-LEVEL FLOW WILL BECOME NORTHWESTERLY TONIGHT/FRIDAY AS INTENSE UPPER-LEVEL RIDGE CONTINUES TO STRENGTHEN IN THE SOUTHWEST US. NORTHWESTERLY FLOW WILL BRING COOLER TEMPERATURES BUT LARGELY DRY WEATHER. MODELS DO INDICATE A SHORTWAVE ROTATING AROUND THE EASTERN US TROUGH ON SATURDAY THAT WOULD BRING SHOWERS INTO IOWA...BUT IT LOOKS LIKE THE CWA WILL REMAIN WEST OF THE PRECIP. THOUGH THE TIMING VARIES AMONG MODEL RUNS AND SOLUTIONS...LONG-RANGE MODELS ARE BECOMING MORE CONSISTENT IN INDICATING THAT THE EASTERN US UPPER- LEVEL TROUGH WILL RETROGRADE INTO THE CENTRAL PLAINS AND DEEPEN...POSSIBLY EVEN CUTTING OFF. DRY NORTHEASTERLY FLOW DOES NOT FAVOR MUCH PRECIPITATION...AND HAVE HELD PRECIP OUT OF THE FORECAST AT LEAST THROUGH TUESDAY. BEYOND THAT... MODEL BLENDS ARE FORCING MUCH HIGHER CHANCES THAN I WOULD CHOOSE TO INCLUDE GIVEN THE AMOUNT OF UNCERTAINTY AND POSSIBLITY FOR A DRY FETCH OF AIR...BUT LEFT THE CHANCES IN FOR COLLABORATION PURPOSES. DO NOT BELIEVE THAT TUESDAY NIGHT THROUGH THURSDAY WOULD BE A WASHOUT...DESPITE PROLONGED PERIOD OF PRECIP CHANCES...BUT COULD SEE PERIODS OF SHOWERS IF THE UPPER LOW DOES INDEED DEEPEN AND RETROGRADE OVER THE CENTRAL PLAINS. EITHER WAY...PATTERN WILL REMAIN COOLER THAN AVERAGE THROUGH NEXT WORK WEEK AND ENTERING THE HOLIDAY WEEKEND. MAYES && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1101 AM EDT THU JUN 27 2013 .SYNOPSIS... THIS AFTERNOON THROUGH THE OVERNIGHT PERIOD, A STRONG SUMMERTIME SYSTEM WILL IMPACT THE REGION, WITH SHOWERS AND THUNDERSTORMS PRODUCING LOCALLY HEAVY RAINFALL. AN UPPER LEVEL TROF WILL REMAIN OVER THE REGION THROUGH THIS WEEKEND BRINGING MORE SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... 1030 AM UPDATE... GRIDS FINALLY UPDATED TO REFLECT CURRENT TRENDS AND THINKING ALONG WITH SUPPORTIVE FLASH FLOOD WATCH (FFA) AND HWO PRODUCTS. LATEST 13Z SUBJECTIVE SFC ANALYSIS PLACES PRIMARY SFC LOW ACROSS WESTERN PA...WITH CORRESPONDING STATIONARY FRONT EXTENDING EAST THROUGH CENTRAL PA...NORTHERN NEW JERSEY...AND EVENTUALLY THE LONG ISLAND SOUND. TO THE SOUTH OF THIS BOUNDARY...DEWPOINTS LARGELY RESIDE IN THE LOWER 70S...WITH AREAS NORTH OF THE FRONT SHOWING CONTINUED NORTHEAST WINDS WITH DEWPOINTS MAINLY IN THE MIDDLE TO UPPER 60S. AS WE PROGRESS INTO THE AFTERNOON HRS...MAIN CONCERNS REMAIN FOCUSED ON TWO AREAS WITH THE FIRST BEING POSSIBLE SEVERE STORMS FOR AREAS THAT DO IN FACT BREAK INTO THE WARM SECTOR PRIOR TO HEAVY RAINS MOVING IN...AND THE SECOND OBVIOUSLY CENTERED ON THE DEVELOPING FLASH FLOOD THREAT. FIRST FOR THE SEVERE THREAT...LATEST VIS SATELLITE IMAGERY SHOWING JUST HIGH CIRRUS ACROSS THE EASTERN ZONES THIS HR WITH PLENTY OF FILTERED SUN MAKING ITS WAY TO THE SURFACE. MAIN CLOUD SHIELD ASSOCIATED WITH HEAVY RAINS STILL TO THE WEST THIS HR BUT MAKING STEADY PROGRESS EAST. LATEST RUC ANALYSIS SHOWS A SLOW MOVING SHORTWAVE WORKING THROUGH THE AREA CURRENTLY...WITH THIS FEATURE EXPECTED TO EXIT OFF TO OUR EAST WITHIN THE NEXT FEW HRS. FCST 925 AND 850 MB WINDS SHOW VERY FAIRLY WEAK SOUTHEASTERLY FLOW THROUGH THIS AFTERNOON LENDING CONCERN THAT AFOREMENTIONED FRONTAL BOUNDARY WILL HAVE A DIFFICULT TIME ADVANCING NORTH THROUGH THE REMAINDER OF THE DAY. MAIN ISSUES PREVENTING WIDESPREAD DEEP MOIST CONVECTION STEMS FROM OVERALL LACK OF INSTABILITY BASED ON BETTER DEWPOINTS/HEATING REMAINING TO THE SOUTH. BIG WILD CARD WILL BE WHETHER THIS FRONT IS ABLE TO MOVE NORTH INTO THE SOUTHERN CATSKILLS/LWR WYOMING VLY/AND POCONOS LATER TODAY. THAT SAID...BEST POTENTIAL SEEMS TO BE FOCUSED OVER THESE AREAS WHERE ISOLATED STRONG WILDS APPEAR TO BE THE BIGGEST THREAT. MOVING ON...FOCUS WILL BECOME MORE HYDRO FOCUSED AS STRONG UPPER WAVE TAPPING AN INCREASING MOIST AND TROPICAL AIRSTREAM MIGRATES EAST WITH TIME. STRONG FORCING ARRIVING FROM THE MAIN MID-LEVEL VORTICITY MAXIMUM WILL BE STRONGLY SUPPORTED BY A NOW DEVELOPING COUPLED JET CIRCULATION WHICH WILL TARGET MUCH OF OUR FCST REGION LATER TODAY INTO TONIGHT. AS THIS OCCURS...LOW-LEVEL JET WINDS ARE PROGGED TO INCREASE TO NEAR 40 KTS AS THE THERMALLY DIRECT COUPLED JET CIRCULATION MATURES WITH TIME. AS THIS OCCURS...AN AIRMASS WITH TROPICAL ORIGINS /SEE LATEST BLENDED TPW SATELLITE IMAGERY/ WITH PWAT VALUES NOW APPROACHING 2" JUST SOUTH OF OUR FCST REGION WILL ADVANCE NORTH AND OVER THE FRONTAL BOUNDARY JUST TO OUR SOUTH /I.E. MADDOX FRONTAL TYPE FF EVENT?/. FOR WHAT ITS WORTH...WFO CTP ALREADY ISSUING ACTIVE FLOOD STATEMENTS AND MAKING REFERENCE TO 3"/HR RAINFALL RATES. OBVIOUSLY AS THIS AIRMASS WORKS OVER THE AREA COMBINED WITH STRONG SYNOPTIC SUPPORT ALOFT...FLASH FLOODING DEFINITELY A LIKELIHOOD LATER TODAY/TONIGHT. AS A RESULT...NO CHANGES TO THE CURRENT FLASH FLOOD PRODUCT ANTICIPATED ON THE DAYSHIFT. 620 AM UPDATE...AREAS OF DENSE FOG CURRENTLY EXTENDS ACROSS THE TWIN TIERS AS CI OVERSPREADS THE REGION. HIGH CLOUDS MAY PREVENT SOME MIXING INITIALLY EARLY THIS MORNING THEREFORE KEPT FOG IN THE FORECAST UNTIL MID MORNING. NO OTHER CHANGES. AT 445 AM...SKIES WERE MAINLY CLEAR OVER THE REGION WITH DENSE VALLEY FOG ACROSS THE TWIN TIERS. MODELS ARE IN MUCH BETTER AGREEMENT THIS MORNING WITH SYSTEM LIFTING NORTHEAST FROM THE OHIO VALLEY. UPPER LEVEL TROF WILL ADVANCE EASTWARD TOWARD THE REGION TODAY BRINGING WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS INTO THE AREA FROM SOUTHWEST TO NORTHEAST FROM EARLY THIS AFTERNOON THROUGH THIS EVENING. SYSTEM WILL HAVE THE CAPACITY FOR LOCALIZED HEAVY RAINFALL AS AIRMASS IS VERY MOIST WITH PWATS OF 1.50-2.00 INCHES. JET DYNAMICS ARE ALSO VERY IMPRESSIVE WITH DOUBLE JET STRUCTURE RESULTING IN STRONG UPPER LEVEL DIVERGENCE THIS EVENING THROUGH THE OVERNIGHT PERIOD. MODELS ARE IN MUCH BETTER AGREEMENT WITH SFC LOW TRACK TAKING FEATURE FROM CENTRAL PA NORTHEAST INTO THE NORTHERN TIER OF PA THEN INTO THE WESTERN CATSKILLS. WITH THIS TRACK FEEL THE MOST LIKELY AREA FOR HEAVY RAINFALL WILL BE ACROSS NE PA INTO THE WESTERN CATSKILLS WHERE LOW LEVEL JET AND BEST MOISTURE ADVECTION WILL RESIDE. A GENERAL 1 TO 2 INCHES OF RAINFALL IS LIKELY OVER THE REGION WITH LOCALIZED AMOUNTS AROUND 3 INCHES OR GREATER POSSIBLE. SEVERE WEATHER LATER TODAY AND INTO THIS EVENING IS STILL A POSSIBILITY BUT WEAK LAPSE RATES AND MID LEVEL WIND FIELDS IS A LIMITING FACTOR. SHEAR WILL INCREASE LATER TODAY THROUGH THIS EVENING AS UPPER LEVEL TROF APPROACHES AND IF ENOUGH DESTABILIZATION OCCURS A FEW CELLS COULD PRODUCE DAMAGING WINDS. THE BEST AREA FOR THIS ACTIVITY WOULD BE THE EASTERN CWA WHERE CAPE VALUES MAY BE MORE SIGNIFICANT. WILL CONTINUE WITH FLASH FLOOD WATCH FOR THE ENTIRE AREA THIS AFTERNOON THROUGH TONIGHT. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... UPPER LEVEL TROF WILL DEEPEN OVER THE REGION DURING THIS PERIOD WITH SFC LOW PRES INITIALLY LIFTING NORTHEAST INTO SOUTHERN QUEBEC THEN RETROGRADING BACK UNDER THE UPPER LEVEL FEATURE. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE PERIOD WITH THE MOST WIDESPREAD COVERAGE EXPECTED DURING THE DAYLIGHT HOURS ENHANCED BY DIURNAL INSTABILITY. MAX TEMPS BOTH FRIDAY AND SATURDAY WILL GENERALLY RANGE IN THE 70S WITH VALLEY AREAS IN NE PA AROUND 80. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... 400 AM EDT UPDATE... PREVIOUS FORECAST IS IN GOOD SHAPE. MINOR CHANGES TO THE TEMPS WERE MADE. KEPT POPS THE SAME. 420 PM WED UPDATE... CONCERNS CONTINUE TO RISE THIS AFTERNOON FOR A POTENTIAL SIGNIFICANT HYDROLOGIC EVENT FOR PORTIONS OF THE EAST COAST LATE THIS WEEKEND INTO MIDWEEK AS A STAGNANT NORTH-SOUTH MERIDIONAL FLOW PATTERN TRANSPORTS LARGE AMOUNTS OF TROPICAL MOISTURE NORTH INTO THE MIDDLE ATLANTIC AND NEW ENGLAND REGIONS. LATEST 12Z GEFS STANDARDIZED ANOMALY GRAPHICS CONTINUE TO ADVERTISE AN INCREASINGLY BLOCKY PATTERN WITH VERY AMPLIFIED HIGH PRESSURE DEVELOPING ACROSS THE INTERMOUNTAIN WEST WITH ADDITIONAL DOWNSTREAM RIDGING EXPECTED TO STRENGTHEN OVER TIME ACROSS THE NORTHERN ATLANTIC. AS HAS BEEN ADVERTISED OVER THE PAST FEW DAYS...VERY DEEP TROUGHING WILL DEVELOP WEST OF OUR FORECAST REGION WITH THE ASSOCIATED TROUGH AXIS EXPECTED TO EXTEND WELL SOUTH INTO THE GULF OF MEXICO BY EARLY WEEK. AS AN INDICATION OF HOW ANOMALOUS THE DEVELOPING PATTERN IS EXPECTED TO BE...LATEST WPC EXTENDED DISCUSSIONS NOW SPEAKING OF POSSIBLE ALL-TIME RECORD HIGHS ACROSS PORTIONS OF THE DESERT SOUTHWEST. MEANWHILE FOR AREAS CLOSER TO US...PWAT ANOMALY GRAPHICS ARRIVING THIS AFTERNOON SHOWING STRONG TROPICAL MOISTURE CONNECTIONS TO THE SOUTH ATLANTIC/CARIBBEAN...WITH AN ADDITIONAL COMPONENT EXPECTED TO ARRIVE FROM THE EAST-CENTRAL PACIFIC. THE CONVERGENCE OF BOTH LOW /MID-LEVEL AIR STREAMS WILL FUNNEL ITS WAY NORTH WITH TIME RESULTING IN WIDESPREAD RAIN/POTENTIALLY HEAVY RAIN DEVELOPMENT. A LITTLE TOO EARLY TO DIVE INTO EXACT DETAILS THIS FAR OUT BUT CONFIDENCE CONTINUES TO INCREASE THAT FLOODING RAINS ARE POSSIBLE SOMEWHERE ALONG THE ATLANTIC SEABOARD BEGINNING THIS WEEKEND AND LASTING THROUGH AT LEAST MIDWEEK. IN ANY EVENT...HAVE CONTINUED LIKELY POPS THROUGH THE PERIOD AND WILL CONTINUE TO ADVERTISE HEAVY RAIN POTENTIAL IN THE HWO PRODUCT. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... 700 AM EDT UPDATE... DENSE FOR HAS SETTLED OVER THE REGION THIS MORNING WITH LIGHT AND VARIABLE WINDS. EXPECT FOG TO START TO MIX OUT AROUND 12Z THIS MORNING. WINDS WILL REMAIN LIGHT THROUGH THE MORNING HOURS. SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING RESULTING IN MVFR. ISOLATED IFR CIGS WILL BE ATTENDANT WITH THE HEAVIER STORMS BUT CONFIDENCE IS LOW ON THE TIMING THEREFOR KEPT THE MENTION OF IFR OUR OF THE TAFS AT THIS TIME. EMBEDDED THUNDERSTORMS WILL BE POSSIBLE WITH THESE SHOWERS. CONFIDENCE WITH THE TIMING OF THESE THUNDERSTORMS ARE LOW AND CHOSE TO KEEP THEM OUT OF THE TAF AT THE MOMENT AS WELL. THESE SHOWERS ARE EXPECTED TO START TO MOVE OUT OF THE AREA FRIDAY MORNING TOWARDS THE NORTH...HOWEVER ANOTHER ROUND OF SHOWERS ARE EXPECTED FRIDAY AFTERNOON. OUTLOOK...FRI THROUGH SUN... FRI...MVFR POSSIBLE IN AFTERNOON SHWRS/STORMS. SAT/SUN/MON...MVFR/IFR RESTRICTIONS POSSIBLE IN RA. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY AFTERNOON FOR PAZ038>040-043-044-047-048-072. NY...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY AFTERNOON FOR NYZ009-015>018-022>025-036-037-044>046- 055>057-062. && $$ SYNOPSIS...RRM NEAR TERM...CMG/RRM SHORT TERM...RRM LONG TERM...CMG/KAH AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1051 AM EDT THU JUN 27 2013 .SYNOPSIS... A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... WATER VAPOR IMAGERY DISPLAYS A SHORTWAVE TROUGH NEAR NE OH THIS MORNING. JUST TO THE EAST OF THE CUSP...WHICH IS FOUND ON THE WESTERN SIDE OF THE UPPER LEVEL CIRCULATION IS FOUND AT THE SURFACE AN AREA OF LOW PRESSURE...WHICH CAN ALSO BE SEEN IN RADAR LOOPS AND SURFACE ANALYSIS AS A WEAK AREA OF LOW PRESSURE. LATEST IR AND VISIBLE SATELLITE IMAGERY SHOWS COOLING CLOUD TOPS ASSOCIATED WITH THE WARM CONVEYOR BELT WHICH WILL CONTINUE TO STREAM MOISTURE NORTHWARD AHEAD OF THE UPPER LEVEL SHORTWAVE. THIS WILL FOCUS THE GREATEST MOISTURE...AND COUPLED WITH THE BEST ISENTROPIC LIFT AND SYNOPTIC LIFT WILL FOCUS THE HEAVIEST RAIN THROUGH THE DAYTIME ACROSS THE SOUTHERN TIER. DAYTIME HEATING MAY TRIGGER SHOWERS AND AN ISOLATED THUNDERSTORM AHEAD OF THE MAIN SLUG OF RAINFALL WHICH WILL ONLY SLOWLY WORK ITS WAY NORTHWARD TODAY. THE 00Z/06Z RUNS OF THE NAM...AND TO A LESSER EXTENT THE 00Z GFS/UKMET/EURO KEEP THE MAJORITY OF THE PRECIPITATION IN FAR SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE DAY. MEANWHILE THE RGEM AND SEVERAL HRRR RUNS ARE FURTHER NORTH...PERHAPS KEYING ON A SUBTLE SURFACE CONVERGENCE BOUNDARY SOUTH OF LAKE ONTARIO. RECALLING AN EVENT A WEEK AGO WHERE THE OUTLYING RGEM DID HAVE THE BEST HANDLE ON A SIMILAR SYSTEM...WILL CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE A BLEND OF BOTH CAMPS OF GUIDANCE. EARLY MORNING RADAR TREND TEND TO SUPPORT THE HRRR/RGEM SOLUTIONS WHICH BRING AN AREA OF RAIN ACROSS WESTERN NEW YORK TODAY. FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF. RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS (00Z NAM/RGEM/GFS/EURO AND 03Z SREF) IS FAIRLY CONSISTENT IN PUTTING THE STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES REGIONS FOR TONIGHT. THIS SAID...06Z RUNS OF THE NAM/GFS HAVE SHIFTED A BIT SOUTH AND EAST...BUT GIVEN THEY HAVE NOT BEEN VERIFYING WELL UP TO THIS POINT...WILL NOT GIVE THESE SOLUTIONS TOO MUCH WEIGHT. A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON DUE TO EXTREMELY SLOW STORM MOTION. WHILE QPFS ARE LESS ELSEWHERE...THERE STILL IS A POTENTIAL...ESPECIALLY CONSIDERING RAINFALL AMOUNTS IN EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL BUFFALO CREEKS TO BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES UP...AND BASED ON THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP THE TIMING FOR THE EASTERN LAKE ONTARIO SECTION OF THE WATCH. OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY CONDITIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE LOW LIFT VERY SLOWLY TO THE NORTH. ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE. THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL. ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY) WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW. IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE QUARTERS OF AN INCH OF RAIN ON FRIDAY. AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS AREA. REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM CONVECTION. SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE POSSIBILITY OF LIMITED SUNSHINE. EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT OF THE 60S DUE TO THE ANTICIPATED RAINFALL. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST PERIOD. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... 12Z TAFS...LINGERING FOG WILL LIFT QUICKLY AS CLOUDS BUILD ACROSS THE REGION. AFTER THIS...ATTENTION TURNS TO AN INCREASING CHANCE FOR SHOWERS TODAY AND TONIGHT. SOME OF THESE COULD BE FAIRLY HEAVY...WITH SOME EMBEDDED THUNDERSTORMS. GIVEN THE ISOLATED NATURE...AND UNCERTAINTY IN TIMING OF THE HEAVIEST SHOWERS...LARGELY KEEP THE TSTMS OUT OF THE TAF...WITH UPSTREAM CONDITIONS KEYING ANY POSSIBLE ADDITION OF TSTMS. AS WINDS BECOME MORE NE...AND AIR MOISTENS...EXPECT LOWERING CIGS AND VSBY THIS EVENING AND OVERNIGHT. OUTLOOK... FRIDAY...MVFR IN SHOWERS. SATURDAY THROUGH MONDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY EVENING FOR NYZ006>008. FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY AFTERNOON FOR NYZ001>005-010>014-019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL/THOMAS SHORT TERM...TJP LONG TERM...WOOD AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
651 AM EDT THU JUN 27 2013 .SYNOPSIS... A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... RAIN IS ON THE WAY FOR WESTERN NEW YORK...BUT IT WILL TAKE ITS TIME. THROUGH DAYBREAK...RADAR SHOWS SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS WORKING INTO WESTERN PENNSYLVANIA. RAIN WILL SPREAD INTO WESTERN PORTIONS OF THE SOUTHERN TIER THROUGH MID- MORNING...THEN GRADUALLY INTO THE REST OF WESTERN NEW YORK THROUGH THIS EVENING. THE MAIN CAUSE OF THE PRECIPITATION WILL BE A SLOWLY APPROACHING UPPER LEVEL TROF. WATER VAPOR SHOWS THIS IS CURRENTLY AN OPEN WAVE AT AROUND 500 MB...BUT IT IS FORECAST TO CLOSE OFF AS IT MERGES WITH A LARGE UPPER LEVEL LOW THROUGH FRIDAY MORNING. WHILE MODEL GUIDANCE IS IN GENERAL AGREEMENT ON THIS PROGRESSION...IT IS STILL A TRICKY FORECAST GIVEN SUBTLE DIFFERENCES WHICH LEAD TO FAIRLY LARGE DIFFERENCES IN QPF FORECASTS. 00Z/06Z RUNS OF THE NAM...AND TO A LESSER EXTENT THE 00Z GFS/UKMET/EURO KEEP THE MAJORITY OF THE PRECIPITATION IN FAR SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE DAY. MEANWHILE THE RGEM AND SEVERAL HRRR RUNS ARE FURTHER NORTH...PERHAPS KEYING ON A SUBTLE SURFACE CONVERGENCE BOUNDARY SOUTH OF LAKE ONTARIO. RECALLING AN EVENT A WEEK AGO WHERE THE OUTLYING RGEM DID HAVE THE BEST HANDLE ON A SIMILAR SYSTEM...WILL CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE A BLEND OF BOTH CAMPS OF GUIDANCE. EARLY MORNING RADAR TREND TEND TO SUPPORT THE HRRR/RGEM SOLUTIONS WHICH BRING AN AREA OF RAIN ACROSS WESTERN NEW YORK TODAY. FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF. RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS (00Z NAM/RGEM/GFS/EURO AND 03Z SREF) IS FAIRLY CONSISTENT IN PUTTING THE STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES REGIONS FOR TONIGHT. THIS SAID...06Z RUNS OF THE NAM/GFS HAVE SHIFTED A BIT SOUTH AND EAST...BUT GIVEN THEY HAVE NOT BEEN VERIFYING WELL UP TO THIS POINT...WILL NOT GIVE THESE SOLUTIONS TOO MUCH WEIGHT. A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON DUE TO EXTREMELY SLOW STORM MOTION. WHILE QPFS ARE LESS ELSEWHERE...THERE STILL IS A POTENTIAL...ESPECIALLY CONSIDERING RAINFALL AMOUNTS IN EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL BUFFALO CREEKS TO BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES UP...AND BASED ON THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP THE TIMING FOR THE EASTERN LAKE ONTARIO SECTION OF THE WATCH. OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY CONDITIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE LOW LIFT VERY SLOWLY TO THE NORTH. ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE. THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL. ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY) WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW. IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE QUARTERS OF AN INCH OF RAIN ON FRIDAY. AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS AREA. REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM CONVECTION. SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE POSSIBILITY OF LIMITED SUNSHINE. EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT OF THE 60S DUE TO THE ANTICIPATED RAINFALL. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST PERIOD. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... 12Z TAFS...LINGERING FOG WILL LIFT QUICKLY AS CLOUDS BUILD ACROSS THE REGION. AFTER THIS...ATTENTION TURNS TO AN INCREASING CHANCE FOR SHOWERS TODAY AND TONIGHT. SOME OF THESE COULD BE FAIRLY HEAVY...WITH SOME EMBEDDED THUNDERSTORMS. GIVEN THE ISOLATED NATURE...AND UNCERTAINTY IN TIMING OF THE HEAVIEST SHOWERS...LARGELY KEEP THE TSTMS OUT OF THE TAF...WITH UPSTREAM CONDITIONS KEYING ANY POSSIBLE ADDITION OF TSTMS. AS WINDS BECOME MORE NE...AND AIR MOISTENS...EXPECT LOWERING CIGS AND VSBY THIS EVENING AND OVERNIGHT. OUTLOOK... FRIDAY...MVFR IN SHOWERS. SATURDAY THROUGH MONDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY EVENING FOR NYZ006>008. FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY AFTERNOON FOR NYZ001>005-010>014-019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...WOOD AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1045 AM EDT THU JUN 27 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM THURSDAY... MORNING STRATUS IS MIXING OUT..THOUGH WITH VARYING AMOUNTS OF CONVECTIVE DEBRIS CLOUDS ADVECTING EAST ACROSS THE AREA. CLOUD COVER MAY PERIODICALLY HINDER INSOLATION IN SOME AREAS...BUT ULTIMATELY EXPECT HIGHS WILL REACH FORECAST VALUES OF MID 80S WEST TO NEAR 90 IN THE SOUTHEAST. OF GREATER CONCERN IS THE APPROACHING UPPER-LEVEL TROUGH AND REMNANT CONVECTIVE VORTICITY JUST WEST OF THE MOUNTAINS. THE TROUGH AXIS WILL CROSS CENTRAL NC DURING PEAK HEATING TODAY...INTERACTING WITH A MODERATELY UNSTABLE AIRMASS (MLCAPE REACHING 1500-2000 J/KG) CHARACTERIZED BY DEWPOINTS IN THE UPPER 60S AND LOWER 70S...AS WELL AS PW OVER 1.75". FURTHER AIDING INSTABILITY WILL BE A POSSIBLE ELEVATED MIXED LAYER...EVIDENT ON THE 12Z KGSO RAOB. THE 850MB TEMP OF 21C LOOKS A BIT ANOMALOUS REGIONALLY...BUT THERE DOES APPEAR TO BE A STREAM OF WARMER 925-850MB ROUNDING THE BASE OF THE MEAN TROUGH AXIS OVER THE TN/OH VALLEY...SO THE POSSIBILITY OF A MODIFIED EML IS NOT DISCOUNTED. IN FACT...A 14Z AIRCRAFT SOUNDING AT KRDU HAS THE SAME THERMAL CHARACTER. 0-6KM EFFECTIVE SHEAR IS NOT PARTICULARLY STRONG THIS MORNING...BUT SHOULD INCREASE TO 20-30KT AS MID-LEVEL WINDS INCREASE AHEAD OF THE TROUGH. RAP SOUNDING EVEN SHOW A MODEST INCREASE IN SOUTHERLY LOW-LEVEL FLOW...WITH 0-1KM SHEAR APPROACHING 30KT AT KFAY BY 21-22Z. WHILE THE DETAILS OF HOW CONVECTION WILL EVOLVE ARE STILL A LITTLE UNCERTAIN...EXPECT DEVELOPMENT IN THE VICINITY OF THE LEE TROUGH OVER THE FOOTHILLS AND WESTERN PIEDMONT DURING THE NEXT FEW HOURS...WITH CLUSTERS OF CONVECTION GROWING UPSCALE AS THEY MOVES EASTWARD WITH THE UPPER TROUGH AND COLD POOL LATE THIS AFTERNOON AND EVENING. THE ENSEMBLE OF HI-RES MODELS SEEM TO FOCUS ON THE 19Z TO 01Z TIME FRAME...WITH BETTER SEVERE POTENTIAL EAST OF HWY 1. MAIN THREATS WILL BE DAMAGING WINDS AND LARGE HAIL. -BLS ONCE CONVECTION CLEARS THE AREA... CONDITIONS SHOULD BE QUIET OVERNIGHT...WITH LOWS IN THE UPPER 60S TO LOWER 70S. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... AS OF 300 AM THURSDAY... MORE OF THE SAME IS EXPECTED FOR FRIDAY AS AFTERNOON/EVENING CONVECTION WILL DEVELOP ONCE AGAIN ACROSS THE REGION. HOWEVER... COVERAGE MAY BE SLIGHTLY LESS (WHEN COMPARED TO THURSDAY) AS CENTRAL NC WILL BE IN-BETWEEN TWO UPPER LEVEL TROUGHS AND THEREFORE DYNAMIC FORCING WILL BE WEAKER. NEVERTHELESS...AT THE SURFACE A LEE TROUGH WILL PROVIDE SUFFICIENT LOW LEVEL CONVERGENCE FOR THE DEVELOPMENT OF SCATTERED THUNDERSTORMS ACROSS THE FORECAST AREA AS A VERY MOIST AND UNSTABLE AIRMASS WILL STILL IN PLACE AND WEAK DISTURBANCES WILL LIKELY MOVE THROUGH THE REGION IN THE DEEP WESTERLY/SOUTHWESTERLY FLOW ALOFT. AS HAS BEEN THE CASE...THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING LOCALIZED FLOODING...SOME DAMAGING WIND GUSTS AND POSSIBLY SOME SMALL HAIL. WITH SLIGHTLY LESS IN THE WAY OF CONVECTIVE COVERAGE...HIGHS MAY BE A COUPLE OF DEGREES HIGHER THAN THURSDAY... GENERALLY WITHIN A DEGREE OR TWO ON EITHER SIDE OF 90. OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY... AN UNUSUALLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST THROUGH MUCH OF THE LONG TERM PERIOD AS A RIDGE BUILDS OVER THE WESTERN HALF OF THE CONUS (EXTENDING UP INTO CANADA)...WITH A DEEP TROUGH OVER THE EASTERN HALF. THIS TROUGH WILL BE CENTERED OVER THE OHIO VALLEY EARLY IN THE PERIOD...BEFORE RETROGRADING SLIGHTLY THROUGH EARLY/MID NEXT WEEK. REGARDLESS...THIS PATTERN WILL LEAVE CENTRAL NC WITHIN A VERY MOIST AIR MASS AS DEEP SOUTHWESTERLY FLOW PERSISTS. AS A RESULT...UNSETTLED WEATHER WILL CONTINUE THROUGH THE ENTIRE LONG TERM PERIOD (IF NOT LONGER) ACROSS CENTRAL NC...WITH ABOVE NORMAL CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY. A COUPLE OF NOTES ABOUT PRECIP CHANCES...ON SATURDAY SOME SLIGHTLY DRIER AIR IS PROGGED TO MOVE INTO THE WESTERN PORTIONS OF THE FORECAST AREA (AS A SURFACE FRONT NUDGES INTO THE REGION) AND THIS COULD HOLD DOWN PRECIP CHANCES ACROSS THAT PART OF THE FORECAST AREA. HOWEVER...MOISTURE QUICKLY RETURNS LATE SATURDAY AND THE BRIEF LULL IN PRECIP SHOULD END. THEN...AS THE UPPER LEVEL TROUGH RETROGRADES SOME TO BEGIN THE WEEK...THE RIDGE OVER THE WESTERN ATLANTIC WILL ALSO RETROGRADE...THEREFORE EVENTUALLY EXERTING SOME MORE INFLUENCE OVER THE REGION BY THE MIDDLE OF THE WEEK. THIS IS WHEN WE MAY START SEEING A DECREASE IN PRECIP COVERAGE...ESPECIALLY OVER EASTERN NC. OTHERWISE...WITH INCREASING FLOW ALOFT...THE SHEAR WILL IMPROVE OVER THE AREA (ESPECIALLY ACROSS THE NORTH AND WEST THROUGH MONDAY AS THE AFOREMENTIONED TROUGH IS CLOSEST TO THE REGION) AND THEREFORE WE SHOULD SEE MORE IN THE WAY OF ORGANIZED CONVECTION OVER THE WEEKEND. THIS MAY RESULT IN SOME STRONG TO SEVERE STORMS...WITH DAMAGING WIND GUSTS BEING THE PRIMARY THREAT. HOWEVER...A SIGNIFICANT WEATHER THREAT WILL LIKELY BE THE INCREASING FLOODING RISK AS THE AREA REMAINS IN THIS EXTENDED WET PATTERN. DAYTIME HIGHS WILL GENERALLY BE BELOW NORMAL THROUGH THE PERIOD...WITH MOSTLY MID 80S EXPECTED. OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AS OF 735 AM THURSDAY... IFR TO MVFR STRATUS SHOULD LIFT AND SCATTER OUT BY 13 TO 14Z. THE THREAT FOR ISOLATED TO SCATTERED CONVECTION WILL CONTINUE THIS MORNING...ESPECIALLY ACROSS THE WESTERN PIEDMONT AS THE MCS COLD POOL MOVES INTO THE AREA FROM THE WEST. WITH A WARM MOIST UNSTABLE AIRMASS IN PLACE ACROSS CENTRAL NC ...AN UPPER LEVEL SHORTWAVE WILL MOVE THROUGH THE REGION RESULTING IN WIDESPREAD SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON. THERE IS FAIRLY HIGH CONFIDENCE THAT THESE STORMS WILL IMPACT ALL TERMINALS BEGINNING AROUND MIDDAY IN THE TRIAD BEFORE SPREADING EASTWARD THROUGH THE EARLY EVENING HOURS. LOOKING BEYOND 18Z THURSDAY: AN UNSETTLED PATTERN WILL PERSIST ALONG THE U.S. EAST COAST THROUGH EARLY NEXT WEEK. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS EACH AFTERNOON WITH THE THREAT OF SUB-VFR CEILINGS AND VISIBILITIES DUE TO FOG AND LOW STRATUS EACH MORNING. && .EQUIPMENT... KRAX WSR-88D WILL BE DOWN FOR MUCH-NEEDED MAINTENANCE TODAY. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...CBL/BLS SHORT TERM...KRR LONG TERM...KRR AVIATION...CBL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 AM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 955 AM CDT THU JUN 27 2013 THUNDER CHANCES AND WIND SPEEDS WILL BE THE CONCERN. FORECAST THINKING REMAINS ON TRACK AFTER LOOKING AT 12Z NAM/RAP/HRRR. INCREASED WINDS A BIT WITH THE RAP SHOWING 850MB WINDS AROUND 30 KNTS...AND 925MB WINDS AROUND 25 KNTS (WHICH SHOULD LEAD TO SFC WINDS 20-30 MPH WITH GUSTS TO 35 MPH). 12Z HRRR DOES SHOW ISOLD SHOWERS THIS AFTERNOON ACROSS NE NORTH DAKOTA INTO WEST CENTRAL MINNESOTA (WHICH IS OUTSIDE OF OUR CURRENT FORECASTED POPS). THIS AREA IS FURTHER AWAY FROM UPPER LEVEL COLDER TEMPERATURES...AND LESS LIKELY TO SEE SHOWERS. WILL MONITOR AND TAKE ANOTHER LOOK WITH THE NEXT UPDATE. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 338 AM CDT THU JUN 27 2013 UPPER LOW OVER MANITOBA NEAR BERENS RIVER WILL DROP SOUTHEAST TODAY TOWARD THE BOUNDARY WATER REGION ALONG MINNESOTA/ONTARIO FOR TONIGHT. SHORT WAVE WHICH CAUSED SCT STORMS TO MOVE THRU NE ND/NW MN AS MOVED EAST WITH STORMS NOW OVER NE MN. AS UPPER LOW MOVES SOUTHEAST EXPECT A RE-GENERATION OF SCATTERED THUNDERSTORMS OVER NW MN IN COOL POCKET ALOFT. SOUNDINGS SHOW STEEP LAPSE RATES AND NEGATIVE LIFTED INDICES IN REGION. WILL MAINTAIN IDEA OF CHC POPS HALLOCK-PARK RAPIDS NORTH AND EAST WITH REST OF THE FCST AREA SEEING SOME DIURNAL CU FORMATION WITH DAYTIME HEATING. STILL WARM TODAY...WITH MOST SITES IN THE LOWER TO MID 80S. WILL MAINTAIN SOME POPS FOR ISOLD/SCT TRW IN NW MN THRU TONIGHT AS LIKE WED NIGHT COULD SEE A FEW STORMS LAST WELL PAST SUNSET DUE TO DYNAMICS ALOFT. LOOKS BREEZY-WINDY TODAY WITH WEST-NORTHWEST WINDS GUSTING TO 25 KTS OR SO IN THE AFTN. BROAD UPPER TROUGH WILL SETTLE SOUTHWARD FRIDAY SPREADING THE RISK OF A FEW SHOWERS/STORMS FARTHER WEST INTO ERN ND DURING THIS TIME PERIOD...THOUGH MAIN CHC WILL REMAIN IN NORTHWEST INTO CENTRAL MN. LOOK FOR A DROP OF 2-4C IN 850 MB TEMPS ALONG WITH INCREASE IN OVERALL CLOUD COVER FRI. THIS WILL GIVE HIGH TEMPS ABOUT 5 DEG COOLER BOTH DAYS WITH HIGHS MOSTLY IN THE 70S. ANOTHER BREEZY- WINDY DAY WITH GUSTS OVER 25 KTS AT TIMES FROM THE NORTHWEST. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 338 AM CDT THU JUN 27 2013 UPPER TROUGH WILL CONTINUE TO SLOWLY DROP SOUTH FRI NIGHT-SAT AND WILL KEEP RISK OF A FEW SHOWERS/STORMS THRU THIS PD...WITH BEST CHC IN MINNESOTA PART OF THE FCST AREA. BY LATE SAT MAIN THREAT SHIFTS SOUTH INTO CNTRL-SRN MN. WITH COOLING AT 850 MB SATURDAY WILL SEE HIGHS ONCE AGAIN IN THE 70S. FOR SUNDAY THROUGH WEDNESDAY...00 UTC GFS/ECMWF IN REASONABLE AGREEMENT THROUGH 00 UTC TUESDAY... DIVERGING THEREAFTER. BOTH SHOW A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS AND A BROAD TROUGH CENTERED ACROSS THE OHIO RIVER VALLEY...PLACING THE FORECAST AREA IN NORTHWEST FLOW ALOFT. MODEL DIFFERENCES EMERGE LATE MONDAY THROUGH MID-WEEK WITH THE INTERACTION BETWEEN A SOUTHWARD PROPAGATING CANADIAN SHORT-WAVE AND THE BROADER TROUGH TO THE SOUTH. BOTH MODELS SUGGEST THESE FEATURES WILL MERGE SOMEWHERE ACROSS THE MIDWEST/CENTRAL PLAINS BY WEDNESDAY...BUT DETAILS ARE SKETCHY AT THIS TIME. FOR NOW...WILL KEEP ALL BLEND CHANCE POPS MONDAY NIGHT THROUGH WEDNESDAY...ALTHOUGH THIS PAINTS AN OVERALL POTENTIAL FOR WETTER CONDITIONS THAN WHAT IS EXPECTED. IT DOES APPEAR LIKELY THAT THE FORECAST AREA WILL REMAIN ON THE COOL-SIDE OF THE MID-LEVEL THERMAL GRADIENT BETWEEN THE RIDGE TO THE WEST AND TROUGH TO THE EAST. THIS SHOULD KEEP TEMPERATURES NEAR SEASONAL NORMALS WITH HIGHS IN THE MID 70S TO LOWER 80S AND LOWS IN && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 653 AM CDT THU JUN 27 2013 EXPECTING VFR CONDITIONS TODAY. BIG STORY WILL BE EXPECTED GUSTY WEST-NORTHWEST WINDS IN THE 15 TO 30 KT RANGE...WINDIEST IN THE PRAIRIES. GOOD MIXING TODAY SHOULD HELP TRANSPORT 30 KTS WINDS TO THE SFC IN GUSTS. SOME CU DEVELOPMENT TODAY ALONG WITH SOME MID AND HIGH LEVEL. DID GO WITH VCTS IN BEMIDJI IN THE AFTN...BUT TIMING IS QUITE DIFFICULT THIS TIME OUT. DID NOT INCLUDE TVF ATTM. && .HYDROLOGY... ISSUED AT 945 PM CDT WED JUN 26 2013 ALL RIVERS AROUND FARGO CONTINUE TO SEE RISES IN THE LEVELS. IT APPEARS THAT THE RED AT FARGO WILL APPROACH MAJOR FLOOD STAGE WITHIN THE NEXT COUPLE OF DAYS...AND THE LATEST GUIDANCE SHOWS LITTLE CHANGE FOR THE FARGO FORECAST POINT. SIMULATIONS INDICATE THAT POINTS DOWNSTREAM OF FARGO WILL ALSO APPROACH OR EXCEED MINOR FLOOD STAGE IN SEVERAL DAYS...FROM HALSTAD THROUGH OSLO MINNESOTA. AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR WILKIN AND RICHLAND COUNTIES...AND A FLOOD ADVISORY HAS BEEN POSTED FOR CASS COUNTY. THE TWO RIVERS RIVER AT HALLOCK HAS RECEDED BELOW ACTION STAGE AND IS EXPECTED TO REMAIN BELOW ACTION STAGE FOR THE NEXT SEVERAL DAYS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...RIDDLE LONG TERM...RIDDLE/ROGERS AVIATION...RIDDLE HYDROLOGY...HOPKINS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
933 AM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 933 AM CDT THU JUN 27 2013 ONLY MINIMAL CHANGES WERE MADE FOR THIS MID MORNING FORECAST UPDATE. INCREASED WINDS JUST A BIT...ESPECIALLY SOUTHWEST...WHERE LATEST GUIDANCE INDICATES A FEW GUSTS TO 30KTS AT TIMES. OTHERWISE...SHOULD BE A DRY/SUNNY/WARM DAY WITH A STEADY NORTHWEST WIND...BREEZY AT TIMES. UPDATE ISSUED AT 640 AM CDT THU JUN 27 2013 PLEASANT MORNING WEATHERWISE ACROSS THE AREA WITH MOSTLY CLEAR SKIES. SOME HIGH CLOUDS EVIDENT ACROSS THE SOUTH...BUT THESE CLOUDS CONTINUE TO PUSH INTO SOUTH DAKOTA. NO CHANGES TO THE FORECAST OTHER THAN FRESHENING UP THE NEAR TERM HOURLY FORECASTS. BREEZY NORTHWEST WINDS WILL DEVELOP BY MID MORNING WITH WARM TEMPERATURES INTO THE 80S EXPECTED TODAY BEFORE A SLIGHT COOL DOWN OCCURS FRIDAY INTO THE WEEKEND. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT THU JUN 27 2013 SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM FOR TODAY. HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE. HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE. HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT. WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A CLEAR AND QUIET NIGHT EXPECTED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 330 AM CDT THU JUN 27 2013 NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST. MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20 KTS. AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT TO TIME AT THIS POINT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 933 AM CDT THU JUN 27 2013 VFR CONDITIONS ARE FORECAST FOR THE 12 UTC TAF CYCLE ACROSS WESTERN AND CENTRAL NORTH DAKOTA. BREEZY NORTHWEST WINDS ARE EXPECTED DURING THE LATE MORNING THROUGH SUNSET...WITH GUSTS OF 20-25 KTS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...AYD LONG TERM...JNS AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
640 AM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 640 AM CDT THU JUN 27 2013 PLEASANT MORNING WEATHERWISE ACROSS THE AREA WITH MOSTLY CLEAR SKIES. SOME HIGH CLOUDS EVIDENT ACROSS THE SOUTH...BUT THESE CLOUDS CONTINUE TO PUSH INTO SOUTH DAKOTA. NO CHANGES TO THE FORECAST OTHER THAN FRESHENING UP THE NEAR TERM HOURLY FORECASTS. BREEZY NORTHWEST WINDS WILL DEVELOP BY MID MORNING WITH WARM TEMPERATURES INTO THE 80S EXPECTED TODAY BEFORE A SLIGHT COOL DOWN OCCURS FRIDAY INTO THE WEEKEND. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT THU JUN 27 2013 SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM FOR TODAY. HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE. HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE. HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT. WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A CLEAR AND QUIET NIGHT EXPECTED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 330 AM CDT THU JUN 27 2013 NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST. MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20 KTS. AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT TO TIME AT THIS POINT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 640 AM CDT THU JUN 27 2013 VFR CONDITIONS ARE FORECAST FOR THE 12 UTC TAF CYCLE ACROSS WESTERN AND CENTRAL NORTH DAKOTA. BREEZY NORTHWEST WINDS ARE EXPECTED DURING THE LATE MORNING THROUGH SUNSET...WITH GUSTS OF 20-25 KTS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JNS SHORT TERM...AYD LONG TERM...JNS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
655 AM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL CONTINUE TO MOVE NORTHEAST OF THE OHIO VALLEY TODAY...WITH A LARGE UPPER LEVEL TROUGH OF LOW PRESSURE SITUATING ITSELF OVER THE EASTERN GREAT LAKES THROUGH THE WEEKEND. OCCASIONAL CHANCES OF SHOWERS AND THUNDERSTORMS WILL BE EXPECTED. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SHORTWAVE TROUGH IS CURRENTLY LOCATED OVER THE ILN CWA...AS A SURFACE LOW DEVELOPS UNDERNEATH. SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP AS A RESULT OF THESE FEATURES. IT HAS BEEN INTERESTING TO WATCH THE VARYING MOTIONS OF THESE SLOW-MOVING CONVECTIVE CLUSTERS...CAUGHT IN DIFFERENT AREAS OF FLOW AROUND THE TROUGH AND SURFACE LOW. OVERALL...AS THIS ENTIRE SYSTEM MOVES TO THE EAST...THE POPS WILL DECREASE FROM WEST TO EAST THROUGH THE MORNING HOURS (LEADING TO A DIURNAL LULL). THE LARGER-SCALE COMPUTER MODELS CONTINUE TO OVERDO PRECIPITATION NORTH OF THE OHIO RIVER ALL THE WAY INTO PENNSYLVANIA...WHILE ALSO STRUGGLING TO PICK UP ON THE SOUTHWARD-PROPAGATING CONVECTION IN THE TENNESSEE VALLEY. HRRR RUNS ARE ADAMANT IN KEEPING ANY THREAT OF HEAVY RAINFALL SOUTH AND EAST OF THE CWA...LEADING TO CONFIDENCE ENOUGH TO CLEAR OUT THE FLASH FLOOD WATCH. MOISTURE WILL NOT BE QUICK TO MOVE OUT TODAY...LEADING TO INCREASES IN THE SKY GRIDS AND DECREASES IN THE MAX TEMP FORECAST. CLEARING APPEARS MOST LIKELY IN THE SW CWA...WHERE HIGHS IN THE MID 80S ARE STILL BEING FORECAST. THE INFLUENCE OF THE TROUGH AND NW FLOW ALOFT WILL COOL TEMPS BY A FEW DEGREES AT HIGHER LEVELS...WHICH SHOULD ALLOW FOR SOME INSTABILITY (ESPECIALLY IN THE WESTERN CWA...PERHAPS AS HIGH AS 1500 J/KG BUT MORE LIKELY AROUND 1000 J/KG). THERE SHOULD ALSO BE ENOUGH LIFT WITH THE LARGE SCALE TROUGH STARTING TO ASSERT ITS INFLUENCE AFTER THE PASSAGE OF THE MORNING SHORTWAVE...WITH PRECIPITATION CHANCES SLIGHTLY FAVORED IN THE NE CWA (CLOSER TO THE DEEPER MOISTURE AND THE TROUGH). MIGHT BE JUST ENOUGH OF THE COMBINATION OF SHEAR AND INSTABILITY TO SUPPORT A FEW STRONG TO SEVERE STORMS...BUT THIS WOULD BE MORE OF A RANDOM CELLULAR CONVECTIVE EVENT...RATHER A THAN WELL-FORCED ORGANIZED SYSTEM. NOT A HUGE RISK...BUT WORTH A HEADS-UP IN THE HWO...AND THE SPC 5% LOOKS GOOD GIVEN THE CURRENT ASSESSMENT. NOT A BIG SPREAD IN TEMPS TODAY IN THE GUIDANCE...WITH THE FORECAST NEAR OR JUST BELOW THE CONSENSUS. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... HIGH-RES MODELS DEPICT THE DEVELOPMENT OF STRONG TO SEVERE THUNDERSTORMS OVER WISCONSIN TODAY...EVENTUALLY MOVING ON A SOUTHEASTERLY TRAJECTORY FROM THERE AFTER SUNSET. THERE MIGHT BE A LITTLE BIT OF SHORTWAVE ENERGY AS HEIGHT FALLS MOVE SE AT THE NOSE OF A 500MB NORTHWESTERLY JET...POINTING DOWN INTO THE SW ILN CWA DURING THE OVERNIGHT HOURS. AFTER RAMPING POPS DOWN DIURNALLY...HAVE SHOWN A SLIGHT INCREASE OVERNIGHT AGAIN. THERE APPEARS TO STILL BE ELEVATED INSTABILITY AVAILABLE...ALONG WITH INCREASING SHEAR THANKS TO THE JET. SO...IF THIS ACTIVITY DOES SURVIVE ALL THE WAY TO INDIANA AND OHIO...THERE COULD BE SOME HAIL ALONG WITH IT. THE SPECIFICS OF THE CONVECTIVE FORECAST BECOME MORE CONVOLUTED FROM FRIDAY THROUGH THE WEEKEND...AS THE LARGE SCALE UPPER TROUGH OVER SOUTHEASTERN CANADA GROWS AND RETROGRADES INTO THE OHIO VALLEY. SUCH A PATTERN IN THE SUMMER USUALLY SUPPORTS DAILY DIURNAL INSTABILITY (AIDED BY THE RELATIVE COOLER CONDITIONS ALOFT)...COMBINING WITH WHATEVER WEAK FORCING CAN COME THROUGH TO PROMOTE OCCASIONAL CONVECTIVE CHANCES. FRIDAY LOOKS SIMILAR TO THURSDAY...WITH OVERALL DIURNAL DEVELOPMENT...AND FAVORING THE NORTHEASTERN CWA FOR COVERAGE AGAIN. ON SATURDAY...A MUCH LARGER LOBE OF VORTICITY WILL ROTATE SOUTH THROUGH THE GREAT LAKES...PROMPTING A MUCH DIFFERENT SCENARIO IN THE FORECAST. POPS AND CLOUDS ARE BOTH ON THE INCREASE FOR SATURDAY (AND STARTING BOTH OF THESE ADJUSTMENTS RATHER EARLY IN THE NORTH)...ALONG WITH A DROP IN MAX TEMPS. THIS TROUGH WILL CLOSE OFF AS AN ELONGATED UPPER LOW OVER THE OHIO VALLEY ON SUNDAY. THE TROUGH WILL FORCE POPS THROUGH THE WEEKEND...WITH LIKELY POPS SATURDAY DURING THE DIURNAL PERIOD...AND HIGH CHANCE FOR SUNDAY. AFTER IT IS MORE CERTAIN WHERE THE TROUGH WILL CLOSE OFF ON SUNDAY...LIKELY POPS MAY ALSO BE NEEDED THERE...AS A SSW-TO-NNE AXIS OF MOISTURE AND FORCING WILL BE PRESENT. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... VERY UNSETTLED PATTERN TO DEVELOP AS AMPLIFIED LONGWAVE FLOW SETS UP AND PERSISTS THROUGH THIS PERIOD. COULDNT REALLY FIND A DECENT PERIOD TO INDICATE PROLONGED DRY CONDITIONS...WITH LONGWAVE TROUGH DEVELOPING/DEEPENING SW TO NE ALONG AND WEST OF THE APPALACHIAN CHAIN. TWO MASSIVE RIDGES...ONE OVER THE WEST CONUS AND ONE OVER THE ATLANTIC...RETROGRADE AND AMPLIFY THROUGH THE PERIOD WITH THE WEAKNESS/TROUGH BETWEEN THE TWO ALSO GAINING AMPLITUDE. NEGATIVE HEIGHT ANOMALIES ARE SIGNIFICANT AS THE TROUGH DEEPENS ESPECIALLY TO THE SOUTH OF THE OHIO VALLEY. SUCH A DEEP TROUGH IN THE HEART OF SUMMER MEANS THAT DAILY FLAREUPS OF CONVECTION ARE LIKELY...AND WILL BE ESPECIALLY LIKELY TIED TO WEAK WAVES MOVING THROUGH THE NWLY FLOW UNDERNEATH THE TROUGH EARLY IN THE PERIOD...AND IN THE SLY FLOW AHEAD OF THE TROUGH LATE IN THE PERIOD AS THE TROUGH AXIS DRIFTS TO THE WEST. LACK OF SCOURING OF THE LOW LEVEL MOISTURE FIELD MEANS THERE WILL BE PLENTY OF MOISTURE AND MARGINAL INSTBY FOR DAILY ROUNDS OF SCT STORMS TIED TO THE DIURNAL HEATING CYCLE. WAVES TO KEY ON /AT LEAST IN THE SHORT TERM/ ARRIVE BOTH FRIDAY AND SATURDAY SO THESE DAYS HAVE RELATIVELY HIGHER RAIN CHANCES...BUT THERE WILL LIKELY BE MANY MORE OF THESE WAVES INTO EARLY NEXT WEEK. TEMPERATURES...WHILE THEY WILL BE A BIT BELOW NORMAL...WON/T BE TOO COOL GIVEN THE CORE OF THE 850MB TEMP/500MB HEIGHT ANOMALIES QUICKLY DIG/RETROGRADE SOUTH AND WEST OF THE AREA. CERTAINLY NO 90S THE FORECAST...BUT A LONGER OF PERIOD OF UPPER 70S TO MID 80S AND RATHER DAMP/MUGGY CONDITIONS IS IN THE OFFING. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... WEAK LOW PRESSURE AND WEAK COLD FRONT WILL SLOWLY PUSH EAST THROUGH OUR REGION THIS MORNING. SOME FORCING IN THE UPPER LEVELS ON THE BACK SIDE OF THE WEAK LOW WILL CONTINUE THE THREAT FOR SHOWERS NEAR THE NRN TAF SITES THROUGH 14Z. BIGGEST CONCERN THIS MORNING IS THE IFR CIGS...SOME OF WHICH ARE BELOW NEAR OR BELOW AIRPORT MINIMUMS. IT WILL TAKE AWHILE FOR THESE CIGS TO RISE TO ABOVE VFR DUE TO DAYTIME HEATING...BUT SHOULD OCCUR BETWEEN 16Z AND 19Z. FOR THIS AFTERNOON INTO TONIGHT...GREAT LAKES AND OHIO VALLEY REGION WILL REMAIN IN A NORTHWEST FLOW ALOFT...ALLOWING OCCASIONAL DISTURBANCES TO DROP INTO THE REGION. THE AIRMASS SHOULD DESTABILIZE FOR SOME SHOWER/THUNDERSTORM DEVELOPMENT. SOME MODELS SUGGEST THAT A SURFACE TROF AXIS MAY PROVIDE SOME LOW LEVEL FORCING AS WELL. THINK COVERAGE WILL BE IN THE 30 TO 40 PERCENT RANGE WITH PERHAPS THE KCMH/KLCK HAVING THE HIGHEST THREAT. GIVEN THAT THE CONVECTION MAY BE DISORGANIZED...HAVE JUST USED THE VCTS/CB AT THE TAF SITES FROM 19Z TO 00Z. FOR THE OVERNIGHT...CANNOT RULE OUR SOME LINGERING SHOWER/THUNDERSTORM ACTIVITY...ESPECIALLY AS SOME MODELS SUGGEST SOME WEAKENING CONVECTION DROPPING DOWN FROM WISCONSIN. DO NOT WANT TO HOLD ONTO MANY HOURS OF VCTS/CB...SO WILL LATER TAF ISSUANCES DICTATE TO SEE WHAT COVERAGE MAY OCCUR. OUTLOOK...THUNDERSTORMS POSSIBLE THROUGH MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...BINAU AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
626 AM CDT THU JUN 27 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 318 AM CDT THU JUN 27 2013 CURRENTLY SEEING SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP ACROSS SOUTH CENTRAL AND SOUTHEAST SOUTH DAKOTA. THESE APPEAR TO BE BASED ALONG AN AREA OF CONVERGENCE WAY UP AT 600 MB. THUS PROBABLY NOT MUCH IN THE WAY OF RAIN REACHING THE GROUND...ALTHOUGH A FEW HUNDREDTHS OF AN INCH ARE POSSIBLE. CAPE ONLY AROUND 100-200 J/KG...THUS NOT EXPECTING THESE TO INTENSIFY MUCH...WITH JUST PERIODIC LIGHTNING STRIKES. MAY SEE ACTION INTENSIFY MORE TOWARDS THE MISSOURI RIVER CLOSER TO 10Z. AS THE LOW LEVEL JET CONTINUES TO INCREASE THIS REGION WILL BE IN A PRETTY GOOD AREA OF CONVERGENCE IN THE 700 TO 800 MB LAYER. BEING LOWER BASED THESE SHOWERS WILL HAVE A BIT MORE CAPE TO WORK WITH AND HAVE A BETTER CHANCE OF PRODUCING A PERIOD OF STEADY RAINFALL. HRRR SEEMS TO BE HANDLING THINGS PRETTY WELL...AND ALSO SUGGESTS COVERAGE AND INTENSITY OF THE STORMS SHOULD INCREASE AFTER 10Z IN THE MISSOURI RIVER CORRIDOR FROM BON HOMME COUNTY SOUTHEAST INTO PORTIONS OF NORTHWEST IOWA AND NORTHEAST NEBRASKA. CAPE WILL REMAIN TOO LOW FOR ANY SEVERE THREAT...BUT AN INCREASE IN LIGHTNING ACTIVITY AND BRIEF HEAVY RAIN SEEM PROBABLE. THIS ACTIVITY SHOULD DISSIPATE AND PUSH SOUTHEAST OF OUR CWA BY 18Z...GIVING WAY TO INCREASING SUNSHINE. HIGHS WILL BE PRETTY SIMILAR TO YESTERDAY...MAYBE A DEGREE OR TWO COOLER IN SPOTS...ESPECIALLY IF CLOUD CLOVER HANGS AROUND A BIT LONGER. BUT OVERALL...AN ABOVE NORMAL TEMPERATURE DAY WITH HIGHS IN THE MID 80S TO AROUND 90 EXPECTED. HUMIDITY LEVELS WILL ALSO BE PRETTY SIMILAR TO YESTERDAY...MAYBE A TOUCH LOWER BY AFTERNOON. WILL BE A BIT ON THE BREEZY SIDE BY AFTERNOON...ESPECIALLY ACROSS THE NORTHEAST HALF OF THE AREA...WITH WINDS GUSTING INTO THE 20 TO 30 MPH RANGE OUT OF THE NORTHWEST. EXPECTING CLEAR SKIES TONIGHT WITH A LIGHT NORTHWESTERLY BREEZE. LOWS SHOULD RUN A COUPLE DEGREES ABOVE AVERAGE...ABOUT 60 TO 65 ACROSS THE AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 318 AM CDT THU JUN 27 2013 FRIDAY LOOKS DRY...WARM AND WINDY WITH NORTHWEST WINDS AVERAGING ABOUT 20 TO 30 MPH IN THE EASTERN CWA. OTHERWISE EXPECTING HIGHS IN THE 80S. SATURDAY WILL SEE COOLER AIR CONTINUE TO WRAP INTO THE REGION AND SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE DURING PEAK HEATING. SOUNDING ANALYSIS SUGGESTS ONLY SKINNY CAPE...AND NOT MUCH OF IT...AVAILABLE FOR UPDRAFT STRENGTH SO NOT PLANNING ON SEVERE. LOOKS A BIT CAPPED IN THE WEST AS WELL SO WILL HAVE POPS MAINLY FROM INTERSTATE 29 EAST. WITH CLOUDS COMING IN LOWERED HIGHS A LITTLE...ESPECIALLY IN THE EAST WHERE 70 TO 75 WILL LIKELY BE THE MAX WHILE CENTRAL SOUTH DAKOTA COULD REACH 80. ANY CHANCE FOR SHOWERS SHOULD QUICKLY DIMINISH WITH PEAK HEATING SO NOT PLANNING ON ANYTHING IN THE EVENING. A GRADUAL DECREASE IN CLOUDS AND WIND WILL ALSO ALLOW FOR A COOL OVERNIGHT LOW...GENERALLY IN THE MID 50S. FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME...THE VARIOUS MODELS CONTINUE TO CONVERGE AND A COOL AND MOSTLY DRY WEATHER PATTERN. MODEL TRENDS FOR THE THIRD DAY ION A ROW PUSH THE RIDGE OVER THE ROCKIES EVEN FARTHER WEST WHILE A TROUGH OF LOW PRESSURE AND ASSOCIATED COOLER THERMAL FIELD SETTLE INTO THE PLAINS STATES...WHICH JUST A COUPLE OF DAYS AGO LOOKED LIKE WOULD BE OVER THE MIDWEST WITH THE PLAINS IN MORE OF A DRY MIXY PATTERN ON THE EDGE OF AN UPPER LEVEL RIDGE. OVERALL SUSPECT THAT HIGHS WILL BE IN THE 70S AND LOWS WILL BE IN THE 50S. PLEASANT WEATHER BUT A BIT ON THE COOL SIDE FOR THOSE LOOKING AT LAKE AND SWIMMING POOL ACTIVITIES. ONE PERIOD WITH THE POTENTIAL TO BE THE COOLEST AND POSSIBLY SEE SOME RAIN SHOWERS WILL BE WEDNESDAY WHERE BOTH THE GFS AND ECMWF SWING SOME UPPER LEVEL SUPPORT SOUTHWARD WITH INCREASING MID AND UPPER LEVEL MOISTURE. IF IT WERE TO CLOUD UP QUICKLY ON WEDNESDAY AND RAIN HIGH TEMPERATURES MAY BARELY CREEP INTO THE 70S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 621 AM CDT THU JUN 27 2013 MAINLY VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. SEEING SCATTERED SHOWERS AND THUNDERSTORMS THIS MORNING...MAINLY ALONG AND SOUTH OF INTERSTATE 90. KSUX HAS THE BEST CHANCE OF SEEING SOME LIGHTNING THIS MORNING...WITH KFSD JUST SEEING A FEW SHOWERS. CONDITIONS WILL MAINLY STAY VFR EVEN IN THE RAIN...ALTHOUGH SOME BRIEF REDUCTIONS TO MVFR ARE POSSIBLE IN THE HEAVIER STORMS. EXPECT THE ACTIVITY TO DISSIPATE BY THIS AFTERNOON...GIVING WAY TO MOSTLY SUNNY SKIES AND NORTHWESTERLY BREEZE GUSTING UP TO AROUND 20 KTS AT KHON AND KFSD. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...08 AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
221 PM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT. && .NEAR TERM /THROUGH TONIGHT/... SEL7 IS POSTED. TORNADO WATCH. GOING TO TAKE QUITE SOME TIME FOR CONVECTION TO PRESS EWD INTO COASTAL NJ PER SEA BREEZE BOUNDARY. POCKETS OF CU FIELDS SEEN ON SATELLITE IMAGERY MIGHT YIELD A STORM THERE THIS AFTN. OTRW WE NEED TO LOOK TO OUR SOUTHWEST. THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED DOWN ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I LIKE THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS OVERALL DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY ACCURATE. THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD) HERE FOR THIS TIME OF YEAR. SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM FRIDAY OVER E PA AND NNJ. FFG IS SO HIGH IN E PA THAT NO FFA THERE. THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED. OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED WET MICROBURST G45KT. TOR POSSIBLE IN STRONG CONVECTION MAINLY ALONG SFC BOUNDARY I95 NWWD. ITS A LOW PROB DUE TO SHEAR NOT BEING EXCESSIVELY STRONG BUT LOWER LCLS AND THE BOUNDARY DO OFFER THE OPPORTUNITY. HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING. NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70. OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR 00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS. WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1640Z COSPA TRYING TO BUST OUT SCT CONVECTION DE VALLEY 21Z THEN SWEEP IT NNEWD THRU NJ LATE THIS AFTN. MY CONFIDENCE ON THIS SOLN IS BELOW AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING. MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER THAN THE LESS RESOLVED NAM/GFS. LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE? THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS. LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION. THIS MORNING HAD SOME 1/4SM DENSE FOG IN FAR NW NJ. EXPECTING A BIT OF THAT LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 330 PM UPDATE. && .SHORT TERM /FRIDAY/... THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY CUT IT TO 6 AM IN THE 330 PM FCST UPDATE AS ITS DIFFICULT TO SEE ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE. DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID 30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA AREA. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND, WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST EACH DAY. A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF NEXT WEEK. WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND 1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR STRONG THUNDERSTORMS WITH HEAVY RAIN. WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THIS AFTERNOON...VFR SCT CLOUDS AOA 5000 FT AND A GENERAL S-SW WIND G15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z. TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL EXPECTED AFTER 07Z MOST TAF LOCATIONS. FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT- BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER 20Z. OUTLOOK... FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND MORNING LOW CLOUDS/FOG. && .MARINE... SCA IS POSTED. WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 16Z SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY FOR AT LEAST ANOTHER WEEK ON THE WATERS. CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY ENTRANCE. SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT. OUTLOOK... THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER THE WEEKEND INTO EARLY NEXT WEEK. && .HYDROLOGY... AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY. WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES. IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY OCCUR DURING THE HEAVIEST DOWNPOURS. && .RIP CURRENTS... AM HOLDING ONTO THE MDT RISK. ITS LOW NOW BUT BY 5 PM MAY BE UP TO MDT AS GRADIENT SLY FLOW INCREASES. THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW JERSEY COAST LATE TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW AND A BIT OF AN INCREASE IN THE SWELL PERIOD. FOR FRIDAY...12Z WW3 IS STILL PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND 15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL LOW-MDT FOR DE. A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC PERIOD. && .CLIMATE... WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS... PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND 00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG TROF IN THE NE USA DAY 9-10 .. JULY 5-6. I`D SIDE WITH GFS/NAEFS ON THIS. SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY COUNTRYSIDE. PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF GENERALLY 1 TO 2 DEGREES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE NORMAL AT KACY AND MAYBE 2.5 ABOVE NORMAL AT KGED. AS OF 6/26 PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL. THE JUNE 1981-2010 AVG IS 73.2. JUNE RAINFALL BELOW.. KILG ALREADY RECORD MONTHLY RFALL AT 10.09 KPHL RANKED #2 AT 8.81 INCHES BEHIND THE 10.06 JUNE 1998 RECORD. KACY RANKED #3 AT 7.20 BEHIND THE 7.57 IN 1935 AND RECORD JUNE TOTAL OF 8.45 IN 1920. KABE STILL RANKED 8TH WETTEST JUNE AT 6.48 INCHES. THE MONTHLY RECORD IS 10.51 IN 1938. OUT OF REACH DAILY RECORD RAINFALL FOR TODAY: ILG 4.77 1938 RDG 3.33 1883 PHL 3.27 1938 ABE 2.70 1938 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR NJZ001-007-008. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT FRIDAY FOR ANZ450>455. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG 221 SHORT TERM...DRAG 221 LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON 221 MARINE...DRAG/ROBERTSON 221 HYDROLOGY... RIP CURRENTS... CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1252 PM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT. && .NEAR TERM /THROUGH TONIGHT/... AT 14Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR SANDY HOOK WESTWARD NEAR RTE 80 THROUGH NNJ INTO NE PA WITH SFC LOW PRES NEAR KMRB OUT TO NRN OHIO AND LOWER MI. THE WFRONT MAY FORCE SOME CONVECTION EARLY THIS AFTN IN NNJ. OTRW THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED DOWN ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I LIKE THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS OVERALL DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY ACCURATE. THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD) HERE FOR THIS TIME OF YEAR. SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM FRIDAY OVER E PA AND NNJ. FFG IS SO HIGH IN E PA THAT NO FFA THERE. THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED. OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED WET MICROBURST G45KT. HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING. NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70. OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR 00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS. WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1640Z COSPA TRYING TO BUST OUT SCT CONVECTION DE VALLEY 21Z THEN SWEEP IT NNEWD THRU NJ LATE THIS AFTN. MY CONFIDENCE ON THIS SOLN IS BELOW AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING. MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER THAN THE LESS RESOLVED NAM/GFS. LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE? THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS. LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION. THIS MORNING HAD SOME 1/4SM DENSE FOG IN FAR NW NJ. EXPECTING A BIT OF THAT LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 330 PM UPDATE. && .SHORT TERM /FRIDAY/... THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY CUT IT TO 6 AM IN THE 330 PM FCST UPDATE AS ITS DIFFICULT TO SEE ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE. DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID 30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA AREA. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND, WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST EACH DAY. A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF NEXT WEEK. WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND 1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR STRONG THUNDERSTORMS WITH HEAVY RAIN. WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THIS AFTERNOON...VFR SCT CLOUDS AOA 5000 FT AND A GENERAL S-SW WIND G15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z. TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL EXPECTED AFTER 07Z MOST TAF LOCATIONS. FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT- BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER 20Z. OUTLOOK... FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND MORNING LOW CLOUDS/FOG. && .MARINE... SCA IS POSTED. WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 16Z SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY FOR AT LEAST ANOTHER WEEK ON THE WATERS. CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY ENTRANCE. SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT. OUTLOOK... THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER THE WEEKEND INTO EARLY NEXT WEEK. && .HYDROLOGY... AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY. WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES. IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY OCCUR DURING THE HEAVIEST DOWNPOURS. && .RIP CURRENTS... AM HOLDING ONTO THE MDT RISK. ITS LOW NOW BUT BY 5 PM MAY BE UP TO MDT AS GRADIENT SLY FLOW INCREASES. THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW JERSEY COAST LATE TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW AND A BIT OF AN INCREASE IN THE SWELL PERIOD. FOR FRIDAY...12Z WW3 IS STILL PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND 15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL LOW-MDT FOR DE. A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC PERIOD. && .CLIMATE... WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS... PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND 00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG TROF IN THE NE USA DAY 9-10 .. JULY 5-6. I`D SIDE WITH GFS/NAEFS ON THIS. SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY COUNTRYSIDE. PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF GENERALLY 1 TO 2 DEGREES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE NORMAL AT KACY AND MAYBE 2.5 ABOVE NORMAL AT KGED. AS OF 6/26 PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL. THE JUNE 1981-2010 AVG IS 73.2. JUNE RAINFALL BELOW.. KILG ALREADY RECORD MONTHLY RFALL AT 10.09 KPHL RANKED #2 AT 8.81 INCHES BEHIND THE 10.06 JUNE 1998 RECORD. KACY RANKED #3 AT 7.20 BEHIND THE 7.57 IN 1935 AND RECORD JUNE TOTAL OF 8.45 IN 1920. KABE STILL RANKED 8TH WETTEST JUNE AT 6.48 INCHES. THE MONTHLY RECORD IS 10.51 IN 1938. OUT OF REACH DAILY RECORD RAINFALL FOR TODAY: ILG 4.77 1938 RDG 3.33 1883 PHL 3.27 1938 ABE 2.70 1938 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY MORNING FOR NJZ001-007-008. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT FRIDAY FOR ANZ450>455. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG 1251 SHORT TERM...DRAG 1251 LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON 1251 MARINE...DRAG/ROBERTSON 1251 HYDROLOGY... RIP CURRENTS... 1251 CLIMATE...1251
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
532 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION... 528 PM CDT SUPERCELLULAR STORM CAPABLE OF GUSTY WINDS AND POSSIBLY SOME HAIL HEADED ACROSS NORTHWEST METRO AND POTENTIALLY TO CHICAGO. SCATTERED CONVECTION CONTINUES TO DEVELOP AHEAD OF SHEARED SHORTWAVE MOVING SOUTHEAST ACROSS SOUTHERN WI. SEVERAL CELLS HAVE HAD A MODE OF SUPERCELLULAR INCLUDING AT LEAST ONE SPLIT IN THE CWA. UPDRAFTS HAVE BEEN QUICKLY DEVELOPING AND MOST RECENT STORM OVER NORTHWEST COOK COUNTY IS EXHIBITING ROTATION AND A WEAK ECHO REGION...SIGNS IT IS LIKELY TO PERSIST FOR A WHILE. SEVERE WIND GUSTS LOOK TO BE THE GREATEST THREAT WITH THIS WITH STRONG DOWNDRAFT POTENTIAL. THERE HAVE ALREADY SEEN A FEW MESONET SITES GUST IN EXCESS OF 40 MPH...INCLUDING 47 MPH AT ALGONQUIN AND LAKE IN THE HILLS WHEN THE STORM LOOKED LESS INTENSE THAN NOW. WHILE THERE IS ROTATION AT SOME LOWER ANGLES ON RADAR...IT BECOMES WEAKER TOWARD THE LOW-LEVELS AND THE ENVIRONMENT CONTINUES TO NOT BE FAVORABLE FOR TORNADOES WITH LIMITED LOW-LEVEL FOCUS. HAIL TO QUARTER SIZE OR LARGER LOOK TO BE PRETTY ISOLATED BUT POSSIBLE UNDER THE HEART OF THE STORM. MTF/IZZI .MESOSCALE DISCUSSION... 1216 PM CDT STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 248 PM CDT THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE. THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE AREA WITH DECREASING CLOUDINESS. WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL. PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4 INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED HEAVIER SHOWERS. THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK. THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE END OF THE PERIOD. THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF YEAR. ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6 FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * TSRA THROUGH 01Z. * LAKE BREEZE/OUTFLOW REACHING ORD/MDW BETWEEN 00Z-01Z...SHIFTING WESTERLY WINDS NORTHEAST. CMS //DISCUSSION...UPDATED 22Z... TSRA MOVING ACROSS NORTHEAST IL AND WILL CONTINUE EAST/SOUTHEAST OVER THE NEXT FEW HOURS WITH ADDITIONAL DEVELOPMENT POSSIBLE THROUGH SUNSET. CONVECTIVE WIND/OUTFLOW OVER NORTHWEST COOK COUNTY WILL BE PUSHING THROUGH ORD IN THE NEXT 20 MINUTES WITH GUSTS 35-40 KTS POSSIBLE. LAKE BREEZE/OUTFLOW FROM CONVECTION ACROSS SOUTHEAST WI MOVING SOUTH THROUGH NORTHERN LAKE COUNTY IL. THIS WILL MOVE SOUTH ACROSS THE CHICAGO AREA TERMINALS OVER THE NEXT FEW HRS SHIFTING WINDS NORTH/NORTHEAST. ADDITIONAL THUNDERSTORMS MAY SPEED THIS BOUNDARY UP AND REFINEMENT TO CURRENT TIMING CAN BE EXPECTED. CMS PREVIOUS 18Z DISCUSSION... THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM. OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT IMPACTS ON THE TERMINALS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH FOR TSRA THROUGH EARLY EVENING. * HIGH FOR WIND SHIFT LATE AFTERNOON/EARLY EVENING...MEDIUM FOR TIMING. CMS //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 238 PM CDT AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY. INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT. WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
513 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION... 1216 PM CDT STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 248 PM CDT THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE. THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE AREA WITH DECREASING CLOUDINESS. WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL. PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4 INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED HEAVIER SHOWERS. THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK. THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE END OF THE PERIOD. THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF YEAR. ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6 FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * TSRA THROUGH 01Z. * LAKE BREEZE/OUTFLOW REACHING ORD/MDW BETWEEN 00Z-01Z...SHIFTING WESTERLY WINDS NORTHEAST. CMS //DISCUSSION...UPDATED 22Z... TSRA MOVING ACROSS NORTHEAST IL AND WILL CONTINUE EAST/SOUTHEAST OVER THE NEXT FEW HOURS WITH ADDITIONAL DEVELOPMENT POSSIBLE THROUGH SUNSET. CONVECTIVE WIND/OUTFLOW OVER NORTHWEST COOK COUNTY WILL BE PUSHING THROUGH ORD IN THE NEXT 20 MINUTES WITH GUSTS 35-40 KTS POSSIBLE. LAKE BREEZE/OUTFLOW FROM CONVECTION ACROSS SOUTHEAST WI MOVING SOUTH THROUGH NORTHERN LAKE COUNTY IL. THIS WILL MOVE SOUTH ACROSS THE CHICAGO AREA TERMINALS OVER THE NEXT FEW HRS SHIFTING WINDS NORTH/NORTHEAST. ADDITIONAL THUNDERSTORMS MAY SPEED THIS BOUNDARY UP AND REFINEMENT TO CURRENT TIMING CAN BE EXPECTED. CMS PREVIOUS 18Z DISCUSSION... THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM. OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT IMPACTS ON THE TERMINALS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH FOR TSRA THROUGH EARLY EVENING. * HIGH FOR WIND SHIFT LATE AFTERNOON/EARLY EVENING...MEDIUM FOR TIMING. CMS //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 238 PM CDT AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY. INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT. WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
305 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION...141 PM CDT CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS SPREADING INTO WESTERN ILLINOIS. IZZI 1216 PM CDT... STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 248 PM CDT THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE. THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE AREA WITH DECREASING CLOUDINESS. WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL. PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4 INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED HEAVIER SHOWERS. THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK. THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE END OF THE PERIOD. THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF YEAR. ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6 FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING. * EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM. OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT IMPACTS ON THE TERMINALS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * HIGH CONFIDENCE THAT LAKE BREEZE WILL REMAIN EAST OF THE TERMINALS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 238 PM CDT AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY. INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT. WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
252 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION... 141 PM CDT CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS SPREADING INTO WESTERN ILLINOIS. IZZI 1216 PM CDT... STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 248 PM CDT THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE. THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE AREA WITH DECREASING CLOUDINESS. WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL. PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4 INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED HEAVIER SHOWERS. THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK. THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE END OF THE PERIOD. THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF YEAR. ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6 FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING. * EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM. OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT IMPACTS ON THE TERMINALS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 238 PM CDT AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY. INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT. WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
245 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION... 141 PM CDT CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS SPREADING INTO WESTERN ILLINOIS. IZZI 1216 PM CDT... STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING. * EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM. OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT IMPACTS ON THE TERMINALS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 238 PM CDT AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY. INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT. WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
142 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION... 141 PM CDT CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS SPREADING INTO WESTERN ILLINOIS. IZZI 1216 PM CDT... STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING. * EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM. OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT IMPACTS ON THE TERMINALS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 304 AM CDT EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND. WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY THROUGH SUNDAY. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
1235 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION...1216 PM CDT STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING. * EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM. OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT IMPACTS ON THE TERMINALS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 304 AM CDT EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND. WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY THROUGH SUNDAY. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1216 PM CDT THU JUN 27 2013 .MESOSCALE DISCUSSION... 1216 PM CDT STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH LITTLE INHIBITION REMAINING BY MID AFTERNOON. WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT. ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND WESTERN INDIANA. OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST CWA TOO. RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT WOULD APPEAR TO BE LARGE HAIL. WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND PROVIDE UPDATES AS NEEDED. IZZI && .DISCUSSION... 359 AM CDT A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA. ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL AREA ON DAYS THAT MOST RESEMBLED THIS ONE. AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING. THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW THUNDERSTORMS. FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY LOWER THAN FOR SATURDAY. MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY. UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING. * INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON. KREIN //DISCUSSION...UPDATED 12Z... FOG HAS DEVELOPED OVERNIGHT ACROSS MUCH OF NORTHERN ILLINOIS AND NORTHWEST INDIANA...BUT SHOULD DISSIPATE BY 13Z AS THE SUN BEGINS TO HEAT THE SURFACE. NORTHWEST WINDS WILL ALSO GRADUALLY INCREASE AROUND THIS TIME WITH A FEW GUSTS INTO THE MID TEENS POSSIBLE THIS AFTERNOON AS WE MIX DEEPLY. THUNDERSTORMS LOOK LIKELY AGAIN TODAY AS THE ATMOSPHERE QUICKLY BECOMES UNSTABLE. BY 16-17Z FORECAST SOUNDINGS INDICATE SURFACE BASED PARCELS WILL BE UNCAPPED...BUT THE BETTER FORCING APPEARS TO ARRIVE LATER IN THE AFTERNOON AS A MID LEVEL DISTURBANCE AND UPPER LEVEL JET BEGIN TO MOVE OVER THE AREA. THUNDERSTORMS ARE EXPECTED TO BECOME STRONG TO SEVERE BUT SHOULD BE SCATTERED IN COVERAGE. THE ONLY SIGNIFICANT FOCUS AT THE SURFACE WOULD BE A LAKE BREEZE THAT IS EXPECTED TO STAY EAST OF THE CHICAGO TERMINALS. THE THUNDERSTORM THREAT SHOULD FADE NOT TOO LONG AFTER SUNSET WITH QUIET CONDITIONS EXPECTED OVERNIGHT. MODEST NORTHWEST FLOW SHOULD INHIBIT FOG FROM DEVELOPING OVERNIGHT. ON FRIDAY...WINDS WILL BE A LITTLE STRONGER OUT OF THE NORTHWEST WITH GUSTS TO AROUND 20 KT POSSIBLE. THERE WILL BE ADDITIONAL CHANCES FOR THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING AT SOME POINT THURSDAY AFTERNOON BUT DUE TO SCATTERED COVERAGE LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING. * MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW CONFIDENCE IT WILL REACH TERMINALS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHC SHRA. SATURDAY...CHC TSRA/SHRA. SUNDAY THROUGH MONDAY...VFR. TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA. BMD && .MARINE... 304 AM CDT EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND. WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY THROUGH SUNDAY. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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 QUAD CITIES IA IL
1259 PM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 1246 PM CDT THU JUN 27 2013 RAP TRENDS CONTINUE TO SHOW THE 800-750MB CONVERGENCE HELPING TO DRIVE THE NORTHERN PART OF THE PRECIPITATION. HOWEVER...IT IS ENCOUNTERING CONSIDERABLE DRY AIR SO NEARLY ALL THE PRECIPITATION IS EVAPORATING BEFORE IT REACHES THE GROUND. SOME SITES HAVE REPORTED RAIN BUT FROM A DECK AROUND 10 KFT. AS SUCH SPRINKLES ARE BEING REPORTED WHICH IS CAUSING BRIEF GUSTY WINDS AND HELPING TO LOWER DEW POINTS/TEMPERATURES. THE CLOUD COVER WILL HELP SUPPRESS TEMPERATURES BUT MOST AREAS ARE ALREADY IN THE MID AND UPPER 80S. WHERE SUN IS STILL OCCURRING TEMPERATURES WILL RISE A BIT MORE DURING THE AFTERNOON. RAP TRENDS CONTINUE TO SUGGEST THE POTENTIAL FOR DIURNAL CONVECTION OVER ROUGHLY THE SOUTHERN QUARTER OF THE CWFA. THE CLOUD COVER BRINGS A QUESTION MARK TO WHETHER OR NOT THE CONVECTIVE TEMPERATURE WILL BE ACHIEVED OVER THE REMAINDER OF THE AREA. ..08.. UPDATE ISSUED AT 957 AM CDT THU JUN 27 2013 12Z SOUNDING SHOWS A RESPECTABLE SFC CAP IN PLACE WITH A CONVECTIVE TEMPERATURE IN THE LOWER 90S. 12Z UA ANALYSIS COMBINED WITH THE MCS AND LIFT TOOLS HELP EXPLAIN THE CURRENT CONVECTION IN THE PLAINS. THE CONVECTION IN SOUTHEAST NEBRASKA IS DRIVEN BY A SMALL SHORTWAVE AND IS RUNNING ALONG THE 850MB MOISTURE GRADIENT. FURTHER NORTH FROM SOUTH DAKOTA INTO NORTHWEST IOWA THERE IS NICE CONVERGENCE IN THE 800-750MB LAYER WITH A THETA E GRADIENT PRESENT. OVERALL FORCING WHEN USED WITH THE MCS AND LIFT TOOLS INDICATE DRY CONDITIONS WILL REMAIN IN PLACE ACROSS THE CWFA DURING THE MORNING HOURS WITH DOWNWARD MOTION ACROSS THE AREA. THE SOUTH DAKOTA/NORTHWEST IOWA CONVECTION WILL SLOWLY DISSIPATE AS IT MOVES INTO DRIER AIR AND THE CONVERGENCE MOVES SOUTH AND EAST. THE MCS/LIFT TOOLS SHOW THE 800-750MB CONVERGENCE MOVING SOUTHEAST AND ENTERING THE FAR SOUTHWEST/SOUTH PARTS OF THE CWFA SHORTLY AFTER MID DAY. HOWEVER...THE THETA E GRADIENT IS VERY WEAK. FCST SOUNDINGS OFF THE RAP SUGGEST CONVECTIVE TEMPERATURES REMAINING AT 90 OR ABOVE BUT SHOW OVERALL LIFT INCREASING DURING THE AFTERNOON AS A VORT MAX MOVES THROUGH. THUS DIURNAL CLOUDS WILL DEVELOP. IF THE RAP TRENDS ON CONVECTIVE TEMPERATURE ARE CORRECT...THE POTENTIAL EXISTS FOR VERY LITTLE IN THE WAY OF AFTERNOON CONVECTION. TRENDS WILL HAVE TO BE MONITORED BUT POPS HAVE BEEN PULLED BACK TO THE FAR SOUTHWEST/SOUTH AND FAR NORTHEAST FOR ISOLATED TO SCATTERED CONVECTION. ..08.. && .SYNOPSIS... ISSUED AT 340 AM CDT THU JUN 27 2013 STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT POPPED UP OVER NW IL THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT THU JUN 27 2013 MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO MAKE IT THIS FAR EAST. A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE SCATTERED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 340 AM CDT THU JUN 27 2013 INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION. THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN. SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1246 PM CDT THU JUN 27 2013 VFR CONDITIONS ARE EXPECTED THROUGH 18Z/28. A LOOSELY ORGANIZED TSRA COMPLEX IS MOVING SOUTHEAST ACROSS SOUTHERN IOWA AND INTO MISSOURI. CONSIDERABLE DRY AIR ALOFT IS CAUSING THE PRECIPITATION TO NEARLY EVAPORATE PRIOR TO REACHING THE GROUND. CLOUD COVER FROM THIS SYSTEM MAY PREVENT DIURNAL CONVECTION FROM OCCURRING ACROSS EASTERN IOWA AND NORTHERN ILLINOIS. IF DIURNAL CONVECTION OCCURS...THE PROBABILITY OF IT AFFECTING A TAF SITE IS UNDER 15 PERCENT. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...DMD SHORT TERM...DMD LONG TERM...14 AVIATION...08
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1232 PM CDT THU JUN 27 2013 .SHORT TERM.../TODAY/... ISSUED AT 357 AM CDT THU JUN 27 2013 WEAK SHORTWAVE WILL CONTINUE TO CUT ACROSS EASTERN SD INTO EASTERN NE AND WESTERN IA THIS MORNING. THE HI-RES MODELS KEEP THE PRECIP CONFINED TO THE SOUTHWEST PORTIONS OF THE FORECAST AREA EXCEPT THE 06Z HRRR WHERE ITS FURTHER EAST AND IS A BIT MORE BULLISH WITH THE COVERAGE. LITTLE MOISTURE AND FORCING WITH THIS SYSTEM AND ANYTHING THAT DEVELOPS WILL BE HIGH BASED AND SO LEANED TOWARD THE HIRES-NMM MODEL RUNS AS IT SEEMED TO HAVE THE BEST SOLUTION WRT TO LOCATION AND TIMING OF PRECIP. CURRENT RADAR TRENDS HAVE THE PRECIP MOVING INTO THE WESTERN FORECAST AREA BY AROUND 10Z OR SHORTLY AFTER AND LOOK TO BE MORE SOUTHEAST. HOWEVER...THE LATEST RAP CORFIDI VECTORS AND STORM MOTION VECTORS SHIFT THE PRECIP MOVEMENT MORE SOUTHERLY AS IT MOVES EAST. HIGH TEMPS TODAY SHOULD BE FAIRLY SIMILAR TO WEDNESDAY...MAYBE SLIGHTLY COOLER OVER THE WEST TO SOUTH WHERE THE PRECIP AND MORE CLOUD COVER WILL BE THIS MORNING. WAS CONFIDENT ENOUGH TO GO ABOVE GUIDANCE FOR HIGHS TODAY. .LONG TERM.../TONIGHT THROUGH WEDNESDAY/... ISSUED AT 357 AM CDT THU JUN 27 2013 NO SIGNIFICANT CONCERNS THROUGH THIS PERIOD BUT WITH DEFINITE PATTERN CHANGE COMING. MCS MAY BE LINGERING OVER SRN IA AT 00Z WITH THERMODYNAMIC FORCING JUST EXITING INTO MO. THIS WILL LEAD TO FAIR WEATHER LATER THU NIGHT AND INTO EARLY FRI AS LONG WAVE PATTERN BEGINS TO AMPLIFY INTO WRN CONUS TROUGH/ERN RIDGE. HOWEVER BY FRI AFTERNOON REMNANTS OF CURRENT COMPACT MANITOBA SHORT WAVE WILL BEGIN DROPPING INTO WRN SIDE OF GREAT LAKES MEAN TROUGH. THIS WILL GRADUALLY INCREASE SUB 3KM MOISTURE NE-SW...AND COUPLED WITH DAYTIME HEATING...PRODUCE WEAK BUT UNCAPPED SEVERAL HUNDRED MLCAPES. THIS WILL LIKELY DEVELOP SCATTERED UNORGANIZED WEAK PEAK HEATING CONVECTION NE...WHICH IS DEPICTED IN NAM AND HI RES MODEL SIMULATED REFLECTIVITY. LATE DAY MIXING PRODUCING THE INSTABILITY WILL ALSO LIKELY ALLOW BRISK NW WINDS TO MIX DOWN AS SLP GRADIENT INCREASES WITH GUSTS AT OR ABOVE 30 MPH POSSIBLE CENTRAL AND NORTH. BY SATURDAY...THERE IS LITTLE EVIDENCE OF ANY QG FORCING AS AFOREMENTIONED VORT AXIS DROPS THROUGH MS VALLEY. MAIN RESULT WILL BE INCREASED DEEP MOISTURE WITH SOUNDINGS SHOWING NEAR SATURATION AT MANY SITES. THIS ENVIRONMENT WILL LIKELY PRODUCE AREAS OF LIGHT SHOWERS INTO SAT...POSSIBLY LINGERING INTO THE SE EARLY EVENING. HAVE RAISED POPS FURTHER THROUGH THE CHANCE CATEGORY. COULD SEE SOME THUNDER BUT NOTHING SEVERE ANTICIPATED. THE LONG WAVE PATTERN WILL CHANGE LITTLE TO END THE WEEKEND WITH PERSISTENT WEST/EAST TROUGH/RIDGE BUT WITH WEAKENING FLOW. SOME RETROGRESSION WILL EVEN OCCUR BY EARLY NEXT WEEK WITH TROUGH EVENTUALLY DRIFTING WWD INTO MS VALLEY. MID/LOWER TROPOSPHERIC FLOW WILL BE RATHER WEAK IN THIS TIME FRAME WITH LITTLE FORCING. THERE IS SOME POTENTIAL FOR PRECIP...BUT CONFIDENCE IN TIMING OR LOCATION IS NOT GREAT ENOUGH TO INCLUDE MENTION AT THE MOMENT. HOWEVER BY LATE TUE INTO WED TROUGH AND ASSOCIATED FORCING INCREASES SLIGHTLY WHICH JUSTIFIES LOW CHANCES BY THAT TIME. TEMPERATURE WISE...READINGS WILL BE BELOW NORMAL WITH CORRESPONDINGLY LOWER DEWPOINTS. FRIDAY COULD VERY WELL BE THE LAST DAY WE EXCEED 80F FOR THE DURATION OF THE PERIOD AREA WIDE. IN FACT GFS/ECMWF H85 TEMP TIME SERIES THROUGH THE FOLLOWING WEEKEND /JUL 6/ SHOWS LITTLE EVIDENCE OF ANY RETURN TO WARM AND HUMID WEATHER. && .AVIATION...27/18Z ISSUED AT 1232 PM CDT THU JUN 27 2013 SCT -SHRA MOVING ACROSS SRN IA WILL AFFECT KDSM/KOTM AT TIMES IN THE NEXT FEW HRS...BUT ANY VSBY RESTRICTIONS WILL BE BRIEF AND GENERALLY 4-6SM. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD WITH HIGH CLOUDS AT TIMES AND NW WINDS INCR/DECR WITH DAY/NIGHT PERIODS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...SMALL AVIATION...LEE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
130 PM MDT THU JUN 27 2013 .UPDATE... ISSUED AT 1053 AM MDT THU JUN 27 2013 JUST COMPLETED AN UPDATE. MAIN CHANGES WERE TO RAISE HIGH TEMPERATURES... ESPECIALLY IN THE SOUTHEAST PORTION OF THE AREA...AND TO ISSUE A RED FLAG WARNING FOR THE SOUTHERN PORTION OF THE AREA...REFER TO FIRE WEATHER SECTION BELOW. TEMPERATURES ARE RISING FAIRLY RAPIDLY AND WITH THE STRONGER COLD AIR ADVECTION NOT EXPECTED TO ARRIVE UNTIL UNTIL LATER...RAISED THE MAXES. GUSTY NORTH WINDS SPREADING OVER THE AREA AND WOULD EXPECT THEM TO STAY ABOUT THE SAME OR GET A LITTLE STRONGER BASED ON AREA VWPS AND WINDS UPSTREAM. PLAN ON KEEPING THE FORECAST DRY THROUGH TONIGHT. MAIN LOW LEVEL CONVERGENCE WILL LIE SOUTH AND EAST OF THE AREA BY 21Z. ALSO NOT A LOT OF MID LEVEL LIFT AROUND AND MAYBE EVEN DOWNWARD MOTION/RISING HEIGHTS BEHIND SHORTWAVE TROUGH THAT IS CURRENTLY MOVING ACROSS THE AREA. SATELLITE AND UPPER AIR ANALYSIS SHOW A DRYING AT MID LEVELS WITH A RATHER STRONG EML MOVING IN AND 700 MB TEMPERATURES OF PLUS 15 TO 17. SO EXPECT TO STAY CAPPED WITH PRECIPITATION DEVELOPING TO THE SOUTH AND EAST OF THE AREA. THE LATEST HRRR CAPTURED THAT SCENARIO WELL. && .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 329 AM MDT THU JUN 27 2013 THE UPPER RIDGE CONTINUES TO AMPLIFY OVER THE WESTERN UNITED STATES THROUGH FRIDAY WITH THE UPPER FLOW OVER THE CENTRAL HIGH PLAINS BECOMING NORTH NORTHWESTERLY BY SATURDAY AND EVEN MORE NORTHERLY BY EARLY SUNDAY MORNING. SEVERAL POORLY DISCERNED WAVES ROTATE AROUND THE PERIPHERY OF THE UPPER HIGH CENTER THAT RETROGRADES MORE WESTERLY DURING THIS PERIOD. THE VORTICITY MAXES SHOWING UP IN THE MODEL SOLUTIONS APPEAR TO BE DIURNALLY DRIVEN CONVECTIVE FEEDBACK ARTIFACTS THAT STAY CONFINED MAINLY TO THE AREAS OF HIGHER TERRAIN ALONG THE ROCKIES AND FRONT RANGE EACH AFTERNOON AND EVENING. A COOLER AREA OF SURFACE HIGH PRESSURE BEHIND A WEAK COLD FRONT SLIDES THROUGH THE NORTHERN HIGH PLAINS AND INTO THE CENTRAL HIGH PLAINS TONIGHT AND EARLY FRIDAY FOR SOME MINOR MODERATION OF HOT TEMPERATURES. RETURN FLOW WILL BRING ADDITIONAL MOISTURE INTO THE REGION...BUT WILL BE LACKING A GOOD GULF CONNECTION NEEDED FOR WIDESPREAD PRECIPITATION. THE FRONT THAT PUSHES UP ALONG THE FRONT RANGE APPEARS TO MOVE EASTWARD OVER THE FORECAST AREA BY FRIDAY EVENING...PROVIDING A NEAR SURFACE CONVERGENT ZONE FOR THUNDERSTORMS DEVELOPMENT TO FOCUS ON. EXPECT ONLY ISOLATED TO SCATTERED THUNDERSTORMS ACROSS MAINLY THE WESTERN SECTIONS OF THE FORECAST AREA FRIDAY EVENING WITH OTHERWISE DRY CONDITIONS THROUGH THE SHORT TERM PORTION OF THE FORECAST. ADDITIONAL MODERATION OF TEMPERATURES WILL OCCUR ON SATURDAY AFTER THE FRONTAL BOUNDARY PUSHES BACK UP AGAINST THE FRONT RANGE FRIDAY NIGHT. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 129 PM MDT THU JUN 27 2013 FRIDAY NIGHT-SUNDAY...HR RIDGE WILL CONTINUE TO DOMINATE THE PATTERN ACROSS THE AREA WITH ITS CENTER REMAINING AROUND THE FOUR CORNERS AREA THROUGH THE PERIOD AND NORTHERLY FLOW ALOFT PREVAILING ACROSS THE CWA. WITH EXPECTED POSITION OF H5 TROUGH LEADING TO A FEW PERIODS OF LARGE SCALE FORCED ASCENT AND EASTERLY FLOW EXPECTED THROUGH MUCH OF THE PERIOD ANTICIPATE PERIODS OF DIURNALLY DRIVEN THUNDERSTORMS EACH EVENING. GIVEN NORTHERLY FLOW ALOFT AND INSTABILITY AND ELEVATED THETA E RIDGE STAYING ACROSS WESTERN PORTIONS OF THE CWA DO NOT THINK STORMS WILL MAKE A GREAT EASTWARD PUSH THROUGH THE PERIOD...WITH AREA IMPACTED DIMINISHING THROUGH SUNDAY AS COOLER AIR SETTLES IN. TEMPERATURES WILL COOL THROUGH THE PERIOD AS SFC HIGH BECOMES CENTERED OVER THE CWA BY SUNDAY. MAY SEE TEMPS STRUGGLE TO CLIMB OUT OF THE LOWER 80S BY THAT POINT. ALSO LOWERED MIN TEMPS SEVERAL DEGREES THROUGH THE PERIOD TO ACCOUNT FOR EXPECTED COOLER AIRMASS DURING THE PERIOD. IN THE EXTENDED....UPPER FLOW PATTERN AMPLIFIES SIGNIFICANTLY BY THE FIRST OF THE WEEK AS MEAN LAYER RIDGE BUILDS/STRENGTHENS ACROSS THE WESTERN CONUS AND MID/UPPER LEVEL LOW EVOLVES OVER THE EASTERN CONUS. THIS MID/UPPER LOW WILL RETROGRADE WESTWARD BEFORE WEAKENING AND SHIFTING BACK EASTWARD LATE IN THE EXTENDED PERIOD. MEANWHILE...A BROAD/WEAK TROUGH DEVELOPS OVER THE NORTHERN PLAINS AND EXTENDS WESTWARD TO THE CENTRAL AND NORTHERN ROCKIES. EASTERLY/SOUTHEASTERLY LOW LEVEL FLOW WILL GRADUALLY BRING HIGHER THETA-E AIR INTO THE AREA DURING THIS PERIOD. THE MORE SIGNIFICANT PUSH OF LOW LEVEL MOISTURE WILL LIKELY HOLD OFF UNTIL MID WEEK WHEN AFOREMENTIONED UPPER TROUGH DEVELOPS OVER THE NORTHERN PLAINS RESULTING IN STRENGTHENING OF BOTH THE LEE SIDE TROUGH AND SOUTHEASTERLY SURFACE FLOW. WHILE CONFIDENCE OF MEETING OR EXCEEDING CLIMATOLOGICALLY NORMAL POP IS RELATIVELY HIGH THROUGH THE PERIOD GIVEN LOW HEIGHT ANOMALIES AND FAVORED NORTHWESTERLY UPPER FLOW...DETERMINING WHICH DAY OR DAYS MAY NECESSITATE HIGHER POPS IS DIFFICULT. MEDIUM RANGE MODELS HAVE NOT BEEN CONSISTENT IN PLACEMENT/TIMING OF SMALL SCALE FEATURES EMBEDDED WITHIN THE NORTH/NORTHWEST FLOW ALOFT AS WELL AS UNCERTAINTY ON LARGER SCALE PATTERN TOWARD THE END OF THE EXTENDED PERIOD GIVEN THE GROWING SPREAD AMONG GFS ENSEMBLE MEMBERS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1139 AM MDT THU JUN 27 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. COLD FRONT IS MOVING THROUGH THE AREA. WINDS WILL BE GUSTY UNTIL EARLY THIS EVENING. WINDS THEN BECOME LIGHT AND VARIABLE THROUGH THE REST OF THE PERIOD. EXPECT ALL THUNDERSTORMS TO STAY TO THE EAST OF THE AREA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING UNTIL 7 PM MDT /8 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. CO...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ253-254. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...LOCKHART LONG TERM...JRM/BRB AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS WICHITA KS
1246 PM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 1245 PM CDT THU JUN 27 2013 THUNDERSTORM DEVELOPMENT IS STILL ON TRACK FOR THIS AFTERNOON...ALTHOUGH HIGHER RESOLUTION GUIDANCE HAS CONTINUED TO GIVE AN EARLIER INITIATION TIME OVER CENTRAL KANSAS THAN OTHER MESO-SYNOPTIC MODELS. THE QUESTION IS...1. WHERE WILL THE OUTFLOW BOUNDARY FROM MORNING CONVECTION OVER NORTHEAST KANSAS SET UP. 2.HOW QUICK WILL THIS ACTIVITY ACTUALLY DEVELOP...AND 3. ITS SPEED ACROSS THE AREA. THE LAST 3-4 RUNS OF THE HRRR CONTINUE TO DEVELOP A LINE NORTHEAST OF RUSSELL...DIVING THE LINE SOUTHEASTWARD ACROSS THE AREA THROUGH THE LATE AFTERNOON HOURS (INITIATION AROUND 19-20Z) AND INTO THE EARLIER EVENING. THE HRRR HAS THE ACTIVITY EXITING INTO OKLAHOMA/MISSOURI BY EVENING (01Z)...WHILE THE NAM IS JUST A BIT SLOWER. ALTHOUGH THE 12Z NAM DID SPEED UP THE PROPAGATION SLIGHTLY. WILL CONTINUE TO WATCH...BUT DO THINK WITH MAXIMUM HEATING AND TEMPS ALREADY AT NEARLY 100 AT NOON...CONVECTION COULD BEGIN IN THE NEXT 2-3 HOURS. MAIN RISKS REMAIN THE SAME AS EARLIER FORECASTER MENTIONED. NO LARGE CHANGES TO THE FORECAST. BILLINGS && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 332 AM CDT THU JUN 27 2013 TODAY & TONIGHT: HIGHLIGHTS: 1) CONTINUANCE OF HEAT ADVISORY FOR MOST AREAS UNTIL 8 PM CDT FOR MOST AREAS. (THE EXCEPTIONS BEING RUSSELL...BARTON & LINCOLN COUNTIES.) 2) "HIGH-END" SVR (+)TSRA FROM LATE THIS AFTERNOON THRU LATE TONIGHT. TODAY: ULTRA HIGH OCTANE LWR-DECK FUEL POOLING ALONG & SE OF A WEAK NEARLY STATIONARY FRONT EXTENDING FROM ERN NEBRASKA TO SW KS WILL PRODUCE ANOTHER OPPRESSIVELY HOT & HUMID WEATHER FOR ALL OF KICT COUNTRY. HEAT ADVISORY IN EFFECT FOR ALL OF CENTRAL...SC & MOST OF CNTRL KS REMAINS IN EFFECT TIL 8 PM. LATE THIS AFTERNOON-LATE TONIGHT: NO DOUBT...THE FOCUS SHIFTS TO SIGNIFICANT SVR (+)TSRA THAT`LL BREAK OUT OVER ALL AREAS. AN INTENSE CYCLONE THAT`LL INVADE THE GREAT LAKES WILL FORCE A STRONG & OBVIOUSLY MASSIVE MID-UPR HIGH COVERING MOST OF THE WRN CONUS SLIGHTLY W. THIS WOULD RESULT IN THE WRN PERIPHERY OF A STRONG UPR-DECK FLOW TO SPREAD SW OVER ERN KS. THIS...IN TURN...WOULD ENABLE A FAIRLY STRONG COLD FRONT TO SURGE SE ACROSS KS INTO AN ULTRA HIGH OCTANE MOIST LWR-DECK ENVIRONMENT COVERING THE CNTRL & ERN PLAINS. (SFC DWPTS: LWR-MID 70S. 925MB: ~20C(!). 850MB: 18-20C. SBCAPES REACH ~6.500J/KG OVER ERN KS LATE THIS AFTERNOON & THIS EVENING & WITH 6KM SHEAR INCREASING TO 40-45KTS & VEERING MARKEDLY WITH TIME SVR (+)TSRA ARE A CERTAINTY FOR MOST OF KICT. AM UPPING THE HAIL & DAMAGING WIND ANTE TO NEARLY TENNISBALL-SIZED & 60-80 MPH RESPECTIVELY WITH THE HAIL THREAT GREATEST LATE THIS AFTERNOON & EARLY THIS EVENING WITH A TRANSITION TO DAMAGING WINDS AS COMPLEX EVOLVES INTO AN MCS. GIVEN THE STRENGTH OF THE UPR-DECK NW FLOW THE COLD FRONT SHOULD STILL EXIT SE KS EARLY FRI MORNING. THIS WEEKEND: A FEW POST-FRONTAL -SHRA/-TSRA MAY STILL FESTER OVER SE KS EARLY FRI MORNING. THERE`LL BE VERY NICE WEATHER THE REMAINDER OF THE WEEKEND AS HIGH PRESSURE SLOWLY BUILDS S/SE ACROSS THE WRN PLAINS. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 322 AM CDT THU JUN 27 2013 THE NEXT CHANCE FOR -TSRA SHOULD ARRIVE MON NGT WITH CHANCES GRADUALLY INCREASING TUE NGT & WED WHEN THE NEXT COLD FRONT IS SCHEDULED TO MOVE TOWARD CNTRL KS. THE BEHAVIOR OF THE FRONT WILL REQUIRE GRADUALLY INCREASING ATTENTION AS MID-WEEK APPROACHES AS DIFFERENCES BETWEEN THE MID-RANGE MODELS EXIST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1245 PM CDT THU JUN 27 2013 THE MAIN AVIATION FORECAST CONCERNS ARE THE THUNDERSTORM CHANCES THIS AFTERNOON AND EVENING AT ALL TERMINALS. UNTIL CONVECTION DEVELOPS...TERMINALS WILL REMAIN VFR WITH RELATIVELY LIGHT SOUTHERLY WINDS. AS THE SURFACE LOW BEGINS TO MOVE SOUTHEAST...CONVECTION WILL BEGIN TO DEVELOP AND IT IS EXPECTED TO FORM NORTHEAST OF KRSL AND MOVE SOUTHEAST ACROSS ALL TERMINALS. CURRENT THINKING IS TIMING WILL BEGIN AT 20-21Z FOR KRSL AND MOVE SOUTHEAST TO KCNU BY 00Z FOR MAIN LINE. THERE MAYBE SOME GIVE AND TAKE WITH THAT TIMING...BUT THE LATEST HIGH RESOLUTION GUIDANCE...HRRR/RAP HAVE BEEN CONSISTENT FOR THE LAST FEW RUNS WITH THAT TIMING. DURING THE CONVECTION HEAVY THUNDERSTORMS ARE POSSIBLE WITH LARGE HAIL AND STRONG WINDS. GUSTS OF 60MPH OR GREATER ARE POSSIBLE. HEAVY RAIN WILL CAUSE VISIBILITIES TO BE REDUCED AND CEILINGS TO DROP. HAVE INCLUDED A TEMP GROUP FOR MODERATE THUNDERSTORMS DROPPING INTO MVFR...BUT COULD SEE IFR TO LIFR CONDITIONS IN THE HEAVIEST OF STORMS...AT LEAST BRIEFLY. AFTER THE STORMS PASS...BEHIND THE COLD FRONT WINDS WILL BE NORTH TO NORTHEASTERLY WITH VFR CONDITIONS EXPECTED. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 104 73 95 69 / 20 50 10 10 HUTCHINSON 104 71 95 67 / 30 40 10 10 NEWTON 103 71 94 67 / 30 50 10 10 ELDORADO 102 71 94 66 / 20 50 10 10 WINFIELD-KWLD 103 74 95 69 / 10 40 20 10 RUSSELL 103 68 96 65 / 30 20 0 10 GREAT BEND 105 69 95 66 / 30 30 0 10 SALINA 103 70 95 67 / 40 40 0 10 MCPHERSON 104 70 95 67 / 40 40 10 10 COFFEYVILLE 99 74 94 68 / 10 50 20 10 CHANUTE 99 72 93 66 / 10 50 20 10 IOLA 98 71 92 65 / 10 60 20 10 PARSONS-KPPF 98 73 93 66 / 10 50 20 10 && .ICT WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ048>053-067>072- 082-083-091>096-098>100. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1141 AM MDT THU JUN 27 2013 .UPDATE... ISSUED AT 1053 AM MDT THU JUN 27 2013 JUST COMPLETED AN UPDATE. MAIN CHANGES WERE TO RAISE HIGH TEMPERATURES... ESPECIALLY IN THE SOUTHEAST PORTION OF THE AREA...AND TO ISSUE A RED FLAG WARNING FOR THE SOUTHERN PORTION OF THE AREA...REFER TO FIRE WEATHER SECTION BELOW. TEMPERATURES ARE RISING FAIRLY RAPIDLY AND WITH THE STRONGER COLD AIR ADVECTION NOT EXPECTED TO ARRIVE UNTIL UNTIL LATER...RAISED THE MAXES. GUSTY NORTH WINDS SPREADING OVER THE AREA AND WOULD EXPECT THEM TO STAY ABOUT THE SAME OR GET A LITTLE STRONGER BASED ON AREA VWPS AND WINDS UPSTREAM. PLAN ON KEEPING THE FORECAST DRY THROUGH TONIGHT. MAIN LOW LEVEL CONVERGENCE WILL LIE SOUTH AND EAST OF THE AREA BY 21Z. ALSO NOT A LOT OF MID LEVEL LIFT AROUND AND MAYBE EVEN DOWNWARD MOTION/RISING HEIGHTS BEHIND SHORTWAVE TROUGH THAT IS CURRENTLY MOVING ACROSS THE AREA. SATELLITE AND UPPER AIR ANALYSIS SHOW A DRYING AT MID LEVELS WITH A RATHER STRONG EML MOVING IN AND 700 MB TEMPERATURES OF PLUS 15 TO 17. SO EXPECT TO STAY CAPPED WITH PRECIPITATION DEVELOPING TO THE SOUTH AND EAST OF THE AREA. THE LATEST HRRR CAPTURED THAT SCENARIO WELL. && .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 329 AM MDT THU JUN 27 2013 THE UPPER RIDGE CONTINUES TO AMPLIFY OVER THE WESTERN UNITED STATES THROUGH FRIDAY WITH THE UPPER FLOW OVER THE CENTRAL HIGH PLAINS BECOMING NORTH NORTHWESTERLY BY SATURDAY AND EVEN MORE NORTHERLY BY EARLY SUNDAY MORNING. SEVERAL POORLY DISCERNED WAVES ROTATE AROUND THE PERIPHERY OF THE UPPER HIGH CENTER THAT RETROGRADES MORE WESTERLY DURING THIS PERIOD. THE VORTICITY MAXES SHOWING UP IN THE MODEL SOLUTIONS APPEAR TO BE DIURNALLY DRIVEN CONVECTIVE FEEDBACK ARTIFACTS THAT STAY CONFINED MAINLY TO THE AREAS OF HIGHER TERRAIN ALONG THE ROCKIES AND FRONT RANGE EACH AFTERNOON AND EVENING. A COOLER AREA OF SURFACE HIGH PRESSURE BEHIND A WEAK COLD FRONT SLIDES THROUGH THE NORTHERN HIGH PLAINS AND INTO THE CENTRAL HIGH PLAINS TONIGHT AND EARLY FRIDAY FOR SOME MINOR MODERATION OF HOT TEMPERATURES. RETURN FLOW WILL BRING ADDITIONAL MOISTURE INTO THE REGION...BUT WILL BE LACKING A GOOD GULF CONNECTION NEEDED FOR WIDESPREAD PRECIPITATION. THE FRONT THAT PUSHES UP ALONG THE FRONT RANGE APPEARS TO MOVE EASTWARD OVER THE FORECAST AREA BY FRIDAY EVENING...PROVIDING A NEAR SURFACE CONVERGENT ZONE FOR THUNDERSTORMS DEVELOPMENT TO FOCUS ON. EXPECT ONLY ISOLATED TO SCATTERED THUNDERSTORMS ACROSS MAINLY THE WESTERN SECTIONS OF THE FORECAST AREA FRIDAY EVENING WITH OTHERWISE DRY CONDITIONS THROUGH THE SHORT TERM PORTION OF THE FORECAST. ADDITIONAL MODERATION OF TEMPERATURES WILL OCCUR ON SATURDAY AFTER THE FRONTAL BOUNDARY PUSHES BACK UP AGAINST THE FRONT RANGE FRIDAY NIGHT. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 329 AM MDT THU JUN 27 2013 INCREASING CONFIDENCE IN THE PATTERN FOR EARLY NEXT WEEK AS GUIDANCE COMES INTO BETTER AGREEMENT. SYNOPTIC PATTERN WILL BE THAT OF A STRENGTHENING AND INCREASING AMPLIFIED H5 TROUGH OVER THE SOUTHWEST CONUS TRANSITIONING TO PACIFIC NORTHWEST WHILE AN UPPER LOW OVER THE OHIO VALLEY DRIFTS WEST TO THE MID-MISSISSIPPI RIVER VALLEY. WHILE SPECIFICS ACROSS MODELS DIFFER...THE GENERAL THEME IS A NORTH-NORTHWEST FLOW AT UPPER LEVELS WITH SOUTHEASTERLY FLOW NEAR THE SURFACE. A WEAK SHORTWAVE TROUGH MAKES ITS WAY AROUND THE RIDGE ON SUNDAY INTO SUNDAY NIGHT WHICH MAY ENHANCE STORMS TRIGGERED OFF THE FRONT RANGE AS THEY MOVE EAST INTO THE CENTRAL HIGH PLAINS. MONDAY AND TUESDAY THE PATTERN BECOMES A LITTLE LESS CLEAR...THOUGH BELIEVE THERE WILL BE SUFFICIENT INSTABILITY FOR STORMS TRIGGERED BY WEAK SHORTWAVE TROUGHS MOVING SOUTH THROUGH THE HIGH PLAINS. ON WEDNESDAY THE UPPER LOW OUT EAST WILL HAVE DRIFTED WEST INTO THE NORTHERN PLAINS AND AN ASSOCIATED COLD FRONT WILL MAKE ITS WAY THROUGH TRIGGERED WHAT LOOKS TO BE WIDESPREAD SHOWERS AND STORMS AND BRINGING COOLER-THAN-NORMAL TEMPS BEHIND IT. SOME GOOD NEWS WITH THIS PATTERN NO MATTER HOW THE PRECIP UNFOLDS IS THAT THERE WILL BE NO FIRE WEATHER CONCERNS DURING THIS PERIOD THANKS TO SOMEWHAT MOIST AIR /DEWPOINTS IN THE 50S/ AND OVERALL WEAK WINDS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1139 AM MDT THU JUN 27 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. COLD FRONT IS MOVING THROUGH THE AREA. WINDS WILL BE GUSTY UNTIL EARLY THIS EVENING. WINDS THEN BECOME LIGHT AND VARIABLE THROUGH THE REST OF THE PERIOD. EXPECT ALL THUNDERSTORMS TO STAY TO THE EAST OF THE AREA. && .FIRE WEATHER... ISSUED AT 1053 AM MDT THU JUN 27 2013 RELATIVE HUMIDITIES OF LESS THAN 20 PERCENT AND TO NEAR 15 PERCENT EXPECT TO OCCUR THIS AFTERNOON. QUESTION WILL BE IF THE WIND GUSTS WILL GET HIGH ENOUGH FOR LONG ENOUGH IN CONCERT WITH THOSE LOW RELATIVE HUMIDITIES. IT WILL BE CLOSE AND IF RELATIVE HUMIDITIES DROP FASTER OR WINDS ARE STRONGER THEN WE WILL HIT IT. SO ISSUED A RED FLAG WARNING FOR LOCATIONS ROUGHLY ALONG AND SOUTH OF A FLAGLER TO GOODLAND TO HILL CITY LINE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING UNTIL 7 PM MDT /8 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. CO...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ253-254. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...LOCKHART LONG TERM...JJM AVIATION...BULLER FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1105 AM MDT THU JUN 27 2013 .UPDATE... ISSUED AT 1053 AM MDT THU JUN 27 2013 JUST COMPLETED AN UPDATE. MAIN CHANGES WERE TO RAISE HIGH TEMPERATURES... ESPECIALLY IN THE SOUTHEAST PORTION OF THE AREA...AND TO ISSUE A RED FLAG WARNING FOR THE SOUTHERN PORTION OF THE AREA...REFER TO FIRE WEATHER SECTION BELOW. TEMPERATURES ARE RISING FAIRLY RAPIDLY AND WITH THE STRONGER COLD AIR ADVECTION NOT EXPECTED TO ARRIVE UNTIL UNTIL LATER...RAISED THE MAXES. GUSTY NORTH WINDS SPREADING OVER THE AREA AND WOULD EXPECT THEM TO STAY ABOUT THE SAME OR GET A LITTLE STRONGER BASED ON AREA VWPS AND WINDS UPSTREAM. PLAN ON KEEPING THE FORECAST DRY THROUGH TONIGHT. MAIN LOW LEVEL CONVERGENCE WILL LIE SOUTH AND EAST OF THE AREA BY 21Z. ALSO NOT A LOT OF MID LEVEL LIFT AROUND AND MAYBE EVEN DOWNWARD MOTION/RISING HEIGHTS BEHIND SHORTWAVE TROUGH THAT IS CURRENTLY MOVING ACROSS THE AREA. SATELLITE AND UPPER AIR ANALYSIS SHOW A DRYING AT MID LEVELS WITH A RATHER STRONG EML MOVING IN AND 700 MB TEMPERATURES OF PLUS 15 TO 17. SO EXPECT TO STAY CAPPED WITH PRECIPITATION DEVELOPING TO THE SOUTH AND EAST OF THE AREA. THE LATEST HRRR CAPTURED THAT SCENARIO WELL. && .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 329 AM MDT THU JUN 27 2013 THE UPPER RIDGE CONTINUES TO AMPLIFY OVER THE WESTERN UNITED STATES THROUGH FRIDAY WITH THE UPPER FLOW OVER THE CENTRAL HIGH PLAINS BECOMING NORTH NORTHWESTERLY BY SATURDAY AND EVEN MORE NORTHERLY BY EARLY SUNDAY MORNING. SEVERAL POORLY DISCERNED WAVES ROTATE AROUND THE PERIPHERY OF THE UPPER HIGH CENTER THAT RETROGRADES MORE WESTERLY DURING THIS PERIOD. THE VORTICITY MAXES SHOWING UP IN THE MODEL SOLUTIONS APPEAR TO BE DIURNALLY DRIVEN CONVECTIVE FEEDBACK ARTIFACTS THAT STAY CONFINED MAINLY TO THE AREAS OF HIGHER TERRAIN ALONG THE ROCKIES AND FRONT RANGE EACH AFTERNOON AND EVENING. A COOLER AREA OF SURFACE HIGH PRESSURE BEHIND A WEAK COLD FRONT SLIDES THROUGH THE NORTHERN HIGH PLAINS AND INTO THE CENTRAL HIGH PLAINS TONIGHT AND EARLY FRIDAY FOR SOME MINOR MODERATION OF HOT TEMPERATURES. RETURN FLOW WILL BRING ADDITIONAL MOISTURE INTO THE REGION...BUT WILL BE LACKING A GOOD GULF CONNECTION NEEDED FOR WIDESPREAD PRECIPITATION. THE FRONT THAT PUSHES UP ALONG THE FRONT RANGE APPEARS TO MOVE EASTWARD OVER THE FORECAST AREA BY FRIDAY EVENING...PROVIDING A NEAR SURFACE CONVERGENT ZONE FOR THUNDERSTORMS DEVELOPMENT TO FOCUS ON. EXPECT ONLY ISOLATED TO SCATTERED THUNDERSTORMS ACROSS MAINLY THE WESTERN SECTIONS OF THE FORECAST AREA FRIDAY EVENING WITH OTHERWISE DRY CONDITIONS THROUGH THE SHORT TERM PORTION OF THE FORECAST. ADDITIONAL MODERATION OF TEMPERATURES WILL OCCUR ON SATURDAY AFTER THE FRONTAL BOUNDARY PUSHES BACK UP AGAINST THE FRONT RANGE FRIDAY NIGHT. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 329 AM MDT THU JUN 27 2013 INCREASING CONFIDENCE IN THE PATTERN FOR EARLY NEXT WEEK AS GUIDANCE COMES INTO BETTER AGREEMENT. SYNOPTIC PATTERN WILL BE THAT OF A STRENGTHENING AND INCREASING AMPLIFIED H5 TROUGH OVER THE SOUTHWEST CONUS TRANSITIONING TO PACIFIC NORTHWEST WHILE AN UPPER LOW OVER THE OHIO VALLEY DRIFTS WEST TO THE MID-MISSISSIPPI RIVER VALLEY. WHILE SPECIFICS ACROSS MODELS DIFFER...THE GENERAL THEME IS A NORTH-NORTHWEST FLOW AT UPPER LEVELS WITH SOUTHEASTERLY FLOW NEAR THE SURFACE. A WEAK SHORTWAVE TROUGH MAKES ITS WAY AROUND THE RIDGE ON SUNDAY INTO SUNDAY NIGHT WHICH MAY ENHANCE STORMS TRIGGERED OFF THE FRONT RANGE AS THEY MOVE EAST INTO THE CENTRAL HIGH PLAINS. MONDAY AND TUESDAY THE PATTERN BECOMES A LITTLE LESS CLEAR...THOUGH BELIEVE THERE WILL BE SUFFICIENT INSTABILITY FOR STORMS TRIGGERED BY WEAK SHORTWAVE TROUGHS MOVING SOUTH THROUGH THE HIGH PLAINS. ON WEDNESDAY THE UPPER LOW OUT EAST WILL HAVE DRIFTED WEST INTO THE NORTHERN PLAINS AND AN ASSOCIATED COLD FRONT WILL MAKE ITS WAY THROUGH TRIGGERED WHAT LOOKS TO BE WIDESPREAD SHOWERS AND STORMS AND BRINGING COOLER-THAN-NORMAL TEMPS BEHIND IT. SOME GOOD NEWS WITH THIS PATTERN NO MATTER HOW THE PRECIP UNFOLDS IS THAT THERE WILL BE NO FIRE WEATHER CONCERNS DURING THIS PERIOD THANKS TO SOMEWHAT MOIST AIR /DEWPOINTS IN THE 50S/ AND OVERALL WEAK WINDS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 551 AM MDT THU JUN 27 2013 VFR CONDITIONS WITH MOSTLY SUNNY SKIES WILL PREVAIL AT BOTH GLD AND MCK WITH SOUTHWEST WINDS TURNING TO THE NORTHWEST AND BECOMING GUSTY THIS AFTERNOON WITH THE PASSAGE OF A FRONTAL BOUNDARY. WIND SPEEDS WILL DIMINISH AFTER 00Z WITH WINDS TURNING TO THE EAST AND THEN BECOMING LIGHT AND VARIABLE AFTER 07Z AS AN AREA OF HIGH PRESSURE MOVES INTO THE REGION. && .FIRE WEATHER... ISSUED AT 1053 AM MDT THU JUN 27 2013 RELATIVE HUMIDITIES OF LESS THAN 20 PERCENT AND TO NEAR 15 PERCENT EXPECT TO OCCUR THIS AFTERNOON. QUESTION WILL BE IF THE WIND GUSTS WILL GET HIGH ENOUGH FOR LONG ENOUGH IN CONCERT WITH THOSE LOW RELATIVE HUMIDITIES. IT WILL BE CLOSE AND IF RELATIVE HUMIDITIES DROP FASTER OR WINDS ARE STRONGER THEN WE WILL HIT IT. SO ISSUED A RED FLAG WARNING FOR LOCATIONS ROUGHLY ALONG AND SOUTH OF A FLAGLER TO GOODLAND TO HILL CITY LINE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...RED FLAG WARNING UNTIL 7 PM MDT /8 PM CDT/ THIS EVENING FOR KSZ013>016-027>029-041-042. CO...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ253-254. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...LOCKHART LONG TERM...JJM AVIATION...LOCKHART FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
117 PM CDT THU JUN 27 2013 .AVIATION... 18Z TAFS FOR KOMA...KLNK...KOFK. GLANCE AT REGIONAL RADAR MOSAIC SHOWING SCT TSRA MOVING SEWD OVER SERN NEB THIS AFTN. WITH CONVECTIVE ACTIVITY STILL HANGING ON AT KOMA AND KLNK...WILL CONTINUE TEMPO GROUPS UNTIL ABOUT 20Z. OTHERWISE VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS THEREAFTER THRU THE REST OF THE FCST PD. DEE PREV DISCUSSION... /ISSUED 332 AM CDT THU JUN 27 2013/ DISCUSSION... QUIET WEATHER WILL ONCE AGAIN BE INTERRUPTED BY NOCTURNAL/MORNING CONVECTION...WITH A CONTINUED CHANCE THROUGH THE DAY. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES A STRENGTHENING UPPER-LEVEL HIGH OVER THE DESERT SOUTHWEST...WITH 500MB HEIGHTS AS HIGH AS 5960M WITH WIDESPREAD 60-90M HEIGHT RISES ACROSS AREAS WEST OF THE ROCKIES. A SEASONALLY STRONG UPPER-LEVEL JET WAS IMPINGING ON THE PACIFIC NORTHWEST...WITH UP TO 130KT WINDS. BROAD 850MB LOW EXTENDED ACROSS THE ROCKIES...WITH RIDGING OVER THE CENTRAL PLAINS. A DRY POCKET WAS NOTED UNDER THE RIDGE...WITH 850MB DEWPOINTS OF -2C TO 2C IN EASTERN NEB/EASTERN KS/SOUTHEAST SD. HIGHER 850MB MOISTURE DID EXTEND FROM TX INTO THE HIGH PLAINS...AND RAP ANALYSIS INDICATED A STRENGTHENING LOW-LEVEL JET REACHING FROM THE HIGH PLAINS INTO SOUTHERN SD...WHERE HIGHER 850MB MOISTURE WAS POOLING. AN AREA OF SHOWERS WITH ISOLATED THUNDER HAS BLOSSOMED OVER CENTRAL/SOUTHEASTERN SD...WITH ECHOES JUST REACHING NORTH CENTRAL TO NORTHEAST NEB BUT NOT MUCH HITTING THE GROUND YET AT AREA OB SITES. MAIN FORECAST CONCERNS ARE SHOWERS/THUNDERSTORMS TODAY...FOLLOWED BY QUIET AND COOLER WEATHER. SHOWERS/ISOLATED THUNDER SHOULD CONTINUE TO FESTER ON THE NOSE OF THE LOW-LEVEL JET...AND SHOULD BE ABLE TO DROP INTO NORTHEAST NEB BY AROUND DAYBREAK AS MID-LEVEL RIDGE AND DRY AIR POCKET SLIDE EASTWARD...ALLOWING MOISTENING TO LOW LEVELS. NAM/RAP/HRRR FORECAST SOUNDINGS KEEP THE PROFILE RATHER STABLE THROUGH THE MORNING AROUND KOFK...SO AM THINKING CHARACTER OF THE ACTIVITY WILL REMAIN MORE IN THE SHOWERS/ISOLATED THUNDER CATEGORY THIS MORNING...RATHER THAN TURNING INTO SOMETHING MORE STORMY. STORMS SHOULD FESTER THROUGH THE DAY...THOUGH THEY MIGHT LOSE SOME COVERAGE NEAR MIDDAY AS 850MB LOW/BOUNDARY REORGANIZES. MEANWHILE...SOUTHEAST NEB SHOULD BE ABLE TO DESTABILIZE A GOOD PART OF THE DAY AHEAD OF THE SHOWERS. AS 850MB FRONT SAGS INTO SOUTHEAST NEB THIS AFTERNOON...WOULD EXPECT MORE OF A THUNDERSTORM MODE AS STORMS DEVELOP IN A MORE UNSTABLE ENVIRONMENT. BULK SHEAR ENVIRONMENT WOULD SUPPORT MORE ORGANIZED STORMS DOWN THERE...BUT STORM DEVELOPMENT REMAINS CONDITIONAL ON WHETHER THE SOUTHERN CWA REMAINS CLEAR LONG ENOUGH TO DESTABILIZE. IF IT DOES...COULD SEE A FEW STORMS REACH SEVERE LIMITS IN SOUTHEAST NEB...WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. STORMS WILL CONTINUE TO SLIDE SOUTH AND OUT OF THE AREA BY MID-EVENING. UPPER-LEVEL FLOW WILL BECOME NORTHWESTERLY TONIGHT/FRIDAY AS INTENSE UPPER-LEVEL RIDGE CONTINUES TO STRENGTHEN IN THE SOUTHWEST US. NORTHWESTERLY FLOW WILL BRING COOLER TEMPERATURES BUT LARGELY DRY WEATHER. MODELS DO INDICATE A SHORTWAVE ROTATING AROUND THE EASTERN US TROUGH ON SATURDAY THAT WOULD BRING SHOWERS INTO IOWA...BUT IT LOOKS LIKE THE CWA WILL REMAIN WEST OF THE PRECIP. THOUGH THE TIMING VARIES AMONG MODEL RUNS AND SOLUTIONS...LONG-RANGE MODELS ARE BECOMING MORE CONSISTENT IN INDICATING THAT THE EASTERN US UPPER- LEVEL TROUGH WILL RETROGRADE INTO THE CENTRAL PLAINS AND DEEPEN...POSSIBLY EVEN CUTTING OFF. DRY NORTHEASTERLY FLOW DOES NOT FAVOR MUCH PRECIPITATION...AND HAVE HELD PRECIP OUT OF THE FORECAST AT LEAST THROUGH TUESDAY. BEYOND THAT... MODEL BLENDS ARE FORCING MUCH HIGHER CHANCES THAN I WOULD CHOOSE TO INCLUDE GIVEN THE AMOUNT OF UNCERTAINTY AND POSSIBLITY FOR A DRY FETCH OF AIR...BUT LEFT THE CHANCES IN FOR COLLABORATION PURPOSES. DO NOT BELIEVE THAT TUESDAY NIGHT THROUGH THURSDAY WOULD BE A WASHOUT...DESPITE PROLONGED PERIOD OF PRECIP CHANCES...BUT COULD SEE PERIODS OF SHOWERS IF THE UPPER LOW DOES INDEED DEEPEN AND RETROGRADE OVER THE CENTRAL PLAINS. EITHER WAY...PATTERN WILL REMAIN COOLER THAN AVERAGE THROUGH NEXT WORK WEEK AND ENTERING THE HOLIDAY WEEKEND. MAYES && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS BUFFALO NY
213 PM EDT THU JUN 27 2013 .SYNOPSIS... A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... WATER VAPOR IMAGERY DISPLAYS A SHORTWAVE TROUGH NEAR NE OH THIS MORNING. JUST TO THE EAST OF THE CUSP...WHICH IS FOUND ON THE WESTERN SIDE OF THE UPPER LEVEL CIRCULATION IS FOUND AT THE SURFACE AN AREA OF LOW PRESSURE...WHICH CAN ALSO BE SEEN IN RADAR LOOPS AND SURFACE ANALYSIS AS A WEAK AREA OF LOW PRESSURE. LATEST IR AND VISIBLE SATELLITE IMAGERY SHOWS COOLING CLOUD TOPS ASSOCIATED WITH THE WARM CONVEYOR BELT WHICH WILL CONTINUE TO STREAM MOISTURE NORTHWARD AHEAD OF THE UPPER LEVEL SHORTWAVE. THIS WILL FOCUS THE GREATEST MOISTURE...AND COUPLED WITH THE BEST ISENTROPIC LIFT AND SYNOPTIC LIFT WILL FOCUS THE HEAVIEST RAIN THROUGH THE DAYTIME ACROSS THE SOUTHERN TIER. DAYTIME HEATING MAY TRIGGER SHOWERS AND AN ISOLATED THUNDERSTORM AHEAD OF THE MAIN SLUG OF RAINFALL WHICH WILL ONLY SLOWLY WORK ITS WAY NORTHWARD TODAY. THE 00Z/06Z RUNS OF THE NAM...AND TO A LESSER EXTENT THE 00Z GFS/UKMET/EURO KEEP THE MAJORITY OF THE PRECIPITATION IN FAR SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE DAY. MEANWHILE THE RGEM AND SEVERAL HRRR RUNS ARE FURTHER NORTH...PERHAPS KEYING ON A SUBTLE SURFACE CONVERGENCE BOUNDARY SOUTH OF LAKE ONTARIO. RECALLING AN EVENT A WEEK AGO WHERE THE OUTLYING RGEM DID HAVE THE BEST HANDLE ON A SIMILAR SYSTEM...WILL CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE A BLEND OF BOTH CAMPS OF GUIDANCE. EARLY MORNING RADAR TREND TEND TO SUPPORT THE HRRR/RGEM SOLUTIONS WHICH BRING AN AREA OF RAIN ACROSS WESTERN NEW YORK TODAY. FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF. RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS (00Z NAM/RGEM/GFS/EURO AND 03Z SREF) IS FAIRLY CONSISTENT IN PUTTING THE STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES REGIONS FOR TONIGHT. THIS SAID...06Z RUNS OF THE NAM/GFS HAVE SHIFTED A BIT SOUTH AND EAST...BUT GIVEN THEY HAVE NOT BEEN VERIFYING WELL UP TO THIS POINT...WILL NOT GIVE THESE SOLUTIONS TOO MUCH WEIGHT. A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON DUE TO EXTREMELY SLOW STORM MOTION. WHILE QPFS ARE LESS ELSEWHERE...THERE STILL IS A POTENTIAL...ESPECIALLY CONSIDERING RAINFALL AMOUNTS IN EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL BUFFALO CREEKS TO BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES UP...AND BASED ON THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP THE TIMING FOR THE EASTERN LAKE ONTARIO SECTION OF THE WATCH. OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY CONDITIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE LOW LIFT VERY SLOWLY TO THE NORTH. ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE. THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL. ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY) WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW. IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE QUARTERS OF AN INCH OF RAIN ON FRIDAY. AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS AREA. REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM CONVECTION. SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE POSSIBILITY OF LIMITED SUNSHINE. EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT OF THE 60S DUE TO THE ANTICIPATED RAINFALL. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST PERIOD. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AT 18Z THE MAIN BAND OF HEAVY RAIN SHOWERS WAS LARGELY CONFINED TO THE SOUTHERN TIER...INCLUDING THE KJHW TERMINAL. THIS BAND OF RAIN WILL CONTINUE TO WEAKEN...THOUGH LOW CIGS MAY LINGER THROUGH THE AFTERNOON. ELSEWHERE...AND MAINLY SOUTH OF LAKE ONTARIO SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO BLOSSOM THROUGH THE AFTERNOON HEAT. THE MAIN SFC LOW WILL TRACK ACROSS PA AND INTO EASTERN NEW YORK STATE THIS AFTERNOON. THIS WILL CARRY THE HEAVY RAIN EASTWARD SUCH THAT IT WILL CLIP JUST THE EASTERN PORTIONS OF THE AREA...INCLUDING THE KART TERMINAL THROUGH THE OVERNIGHT. ELSEWHERE A LULL IN THE SHOWERS AND THUNDERSTORMS THIS EVENING BEFORE ADDITIONAL SHOWERS...AND POSSIBLE THUNDER ADVANCE TOWARDS WNY AHEAD OF THE NEXT SHORTWAVE. CIGS AND VSBYS MAY LOWER TO IFR/MVFR IN ANY SHOWER AND THUNDERSTORM ACTIVITY. WITH THE WINDS SHIFTING TO A NORTHERLY FLOW AS THE SURFACE LOW TRACKS EASTWARD CIGS OVERNIGHT AND TOMORROW MORNING WILL LIKELY DROP TO LOW END MVFR OR IFR. OUTLOOK... FRIDAY AFTERNOON...MVFR IN SHOWERS. SATURDAY THROUGH TUESDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH THROUGH FRIDAY EVENING FOR NYZ006>008. FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ001>005-010>014- 019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL/THOMAS SHORT TERM...TJP LONG TERM...WOOD AVIATION...THOMAS MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1257 PM EDT THU JUN 27 2013 .SYNOPSIS... THIS AFTERNOON THROUGH THE OVERNIGHT PERIOD, A STRONG SUMMERTIME SYSTEM WILL IMPACT THE REGION, WITH SHOWERS AND THUNDERSTORMS PRODUCING LOCALLY HEAVY RAINFALL. AN UPPER LEVEL TROF WILL REMAIN OVER THE REGION THROUGH THIS WEEKEND BRINGING MORE SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... 1030 AM UPDATE... GRIDS FINALLY UPDATED TO REFLECT CURRENT TRENDS AND THINKING ALONG WITH SUPPORTIVE FLASH FLOOD WATCH (FFA) AND HWO PRODUCTS. LATEST 13Z SUBJECTIVE SFC ANALYSIS PLACES PRIMARY SFC LOW ACROSS WESTERN PA...WITH CORRESPONDING STATIONARY FRONT EXTENDING EAST THROUGH CENTRAL PA...NORTHERN NEW JERSEY...AND EVENTUALLY THE LONG ISLAND SOUND. TO THE SOUTH OF THIS BOUNDARY...DEW POINTS LARGELY RESIDE IN THE LOWER 70S...WITH AREAS NORTH OF THE FRONT SHOWING CONTINUED NORTHEAST WINDS WITH DEW POINTS MAINLY IN THE MIDDLE TO UPPER 60S. AS WE PROGRESS INTO THE AFTERNOON HRS...MAIN CONCERNS REMAIN FOCUSED ON TWO AREAS WITH THE FIRST BEING POSSIBLE SEVERE STORMS FOR AREAS THAT DO IN FACT BREAK INTO THE WARM SECTOR PRIOR TO HEAVY RAINS MOVING IN...AND THE SECOND OBVIOUSLY CENTERED ON THE DEVELOPING FLASH FLOOD THREAT. FIRST FOR THE SEVERE THREAT...LATEST VIS SATELLITE IMAGERY SHOWING JUST HIGH CIRRUS ACROSS THE EASTERN ZONES THIS HR WITH PLENTY OF FILTERED SUN MAKING ITS WAY TO THE SURFACE. MAIN CLOUD SHIELD ASSOCIATED WITH HEAVY RAINS STILL TO THE WEST THIS HR BUT MAKING STEADY PROGRESS EAST. LATEST RUC ANALYSIS SHOWS A SLOW MOVING SHORTWAVE WORKING THROUGH THE AREA CURRENTLY...WITH THIS FEATURE EXPECTED TO EXIT OFF TO OUR EAST WITHIN THE NEXT FEW HRS. FCST 925 AND 850 MB WINDS SHOW VERY FAIRLY WEAK SOUTHEASTERLY FLOW THROUGH THIS AFTERNOON LENDING CONCERN THAT AFOREMENTIONED FRONTAL BOUNDARY WILL HAVE A DIFFICULT TIME ADVANCING NORTH THROUGH THE REMAINDER OF THE DAY. MAIN ISSUES PREVENTING WIDESPREAD DEEP MOIST CONVECTION STEMS FROM OVERALL LACK OF INSTABILITY BASED ON BETTER DEW POINTS/HEATING REMAINING TO THE SOUTH. BIG WILD CARD WILL BE WHETHER THIS FRONT IS ABLE TO MOVE NORTH INTO THE SOUTHERN CATSKILLS/LWR WYOMING VLY/AND POCONOS LATER TODAY. THAT SAID...BEST POTENTIAL SEEMS TO BE FOCUSED OVER THESE AREAS WHERE ISOLATED STRONG WILDS APPEAR TO BE THE BIGGEST THREAT. MOVING ON...FOCUS WILL BECOME MORE HYDRO FOCUSED AS STRONG UPPER WAVE TAPPING AN INCREASING MOIST AND TROPICAL AIRSTREAM MIGRATES EAST WITH TIME. STRONG FORCING ARRIVING FROM THE MAIN MID-LEVEL VORTICITY MAXIMUM WILL BE STRONGLY SUPPORTED BY A NOW DEVELOPING COUPLED JET CIRCULATION WHICH WILL TARGET MUCH OF OUR FCST REGION LATER TODAY INTO TONIGHT. AS THIS OCCURS...LOW-LEVEL JET WINDS ARE PROGGED TO INCREASE TO NEAR 40 KTS AS THE THERMALLY DIRECT COUPLED JET CIRCULATION MATURES WITH TIME. AS THIS OCCURS...AN AIRMASS WITH TROPICAL ORIGINS /SEE LATEST BLENDED TPW SATELLITE IMAGERY/ WITH PWAT VALUES NOW APPROACHING 2" JUST SOUTH OF OUR FCST REGION WILL ADVANCE NORTH AND OVER THE FRONTAL BOUNDARY JUST TO OUR SOUTH /I.E. MADDOX FRONTAL TYPE FF EVENT?/. FOR WHAT ITS WORTH...WFO CTP ALREADY ISSUING ACTIVE FLOOD STATEMENTS AND MAKING REFERENCE TO 3"/HR RAINFALL RATES. OBVIOUSLY AS THIS AIRMASS WORKS OVER THE AREA COMBINED WITH STRONG SYNOPTIC SUPPORT ALOFT...FLASH FLOODING DEFINITELY A LIKELIHOOD LATER TODAY/TONIGHT. AS A RESULT...NO CHANGES TO THE CURRENT FLASH FLOOD PRODUCT ANTICIPATED ON THE DAY SHIFT. 620 AM UPDATE...AREAS OF DENSE FOG CURRENTLY EXTENDS ACROSS THE TWIN TIERS AS CI OVERSPREADS THE REGION. HIGH CLOUDS MAY PREVENT SOME MIXING INITIALLY EARLY THIS MORNING THEREFORE KEPT FOG IN THE FORECAST UNTIL MID MORNING. NO OTHER CHANGES. AT 445 AM...SKIES WERE MAINLY CLEAR OVER THE REGION WITH DENSE VALLEY FOG ACROSS THE TWIN TIERS. MODELS ARE IN MUCH BETTER AGREEMENT THIS MORNING WITH SYSTEM LIFTING NORTHEAST FROM THE OHIO VALLEY. UPPER LEVEL TROF WILL ADVANCE EASTWARD TOWARD THE REGION TODAY BRINGING WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS INTO THE AREA FROM SOUTHWEST TO NORTHEAST FROM EARLY THIS AFTERNOON THROUGH THIS EVENING. SYSTEM WILL HAVE THE CAPACITY FOR LOCALIZED HEAVY RAINFALL AS AIRMASS IS VERY MOIST WITH PWATS OF 1.50-2.00 INCHES. JET DYNAMICS ARE ALSO VERY IMPRESSIVE WITH DOUBLE JET STRUCTURE RESULTING IN STRONG UPPER LEVEL DIVERGENCE THIS EVENING THROUGH THE OVERNIGHT PERIOD. MODELS ARE IN MUCH BETTER AGREEMENT WITH SFC LOW TRACK TAKING FEATURE FROM CENTRAL PA NORTHEAST INTO THE NORTHERN TIER OF PA THEN INTO THE WESTERN CATSKILLS. WITH THIS TRACK FEEL THE MOST LIKELY AREA FOR HEAVY RAINFALL WILL BE ACROSS NE PA INTO THE WESTERN CATSKILLS WHERE LOW LEVEL JET AND BEST MOISTURE ADVECTION WILL RESIDE. A GENERAL 1 TO 2 INCHES OF RAINFALL IS LIKELY OVER THE REGION WITH LOCALIZED AMOUNTS AROUND 3 INCHES OR GREATER POSSIBLE. SEVERE WEATHER LATER TODAY AND INTO THIS EVENING IS STILL A POSSIBILITY BUT WEAK LAPSE RATES AND MID LEVEL WIND FIELDS IS A LIMITING FACTOR. SHEAR WILL INCREASE LATER TODAY THROUGH THIS EVENING AS UPPER LEVEL TROF APPROACHES AND IF ENOUGH DESTABILIZATION OCCURS A FEW CELLS COULD PRODUCE DAMAGING WINDS. THE BEST AREA FOR THIS ACTIVITY WOULD BE THE EASTERN CWA WHERE CAPE VALUES MAY BE MORE SIGNIFICANT. WILL CONTINUE WITH FLASH FLOOD WATCH FOR THE ENTIRE AREA THIS AFTERNOON THROUGH TONIGHT. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... UPPER LEVEL TROF WILL DEEPEN OVER THE REGION DURING THIS PERIOD WITH SFC LOW PRES INITIALLY LIFTING NORTHEAST INTO SOUTHERN QUEBEC THEN RETROGRADING BACK UNDER THE UPPER LEVEL FEATURE. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE PERIOD WITH THE MOST WIDESPREAD COVERAGE EXPECTED DURING THE DAYLIGHT HOURS ENHANCED BY DIURNAL INSTABILITY. MAX TEMPS BOTH FRIDAY AND SATURDAY WILL GENERALLY RANGE IN THE 70S WITH VALLEY AREAS IN NE PA AROUND 80. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... 1 PM THU DISC... GLOBAL MODEL/WPC CONSENSUS CONTS TO SUGGEST QUITE AN AMPLIFIED PATN FOR THIS TIME OF YEAR...WITH A SIG WRN CONUS/CANADIAN RIDGE...AND ERN CONUS TROUGH. THIS LIKELY SPELLS A WET PATN FOR NY/PA...WITH A SUSTAINED DEEP SRLY FLOW...AND LIKELY S/WV IMPULSES RIDING NWD/NEWD UP THE FRONT SIDE OF THE AFOREMENTIONED TROUGH AXIS. THUS...SCTD-NUMEROUS/LIKELY POPS WILL BE RETAINED FOR MUCH OF THE PD. ALTHOUGH MUGGY CONDS ARE FORESEEN...PERSISTENT PCPN SHOULD KEEP HIGH TEMPS IN THE 70S-LWR 80S EACH DAY. PREV DISC... 400 AM EDT UPDATE... PREVIOUS FORECAST IS IN GOOD SHAPE. MINOR CHANGES TO THE TEMPS WERE MADE. KEPT POPS THE SAME. EARLIER DISC... 420 PM WED UPDATE... CONCERNS CONTINUE TO RISE THIS AFTERNOON FOR A POTENTIAL SIGNIFICANT HYDROLOGIC EVENT FOR PORTIONS OF THE EAST COAST LATE THIS WEEKEND INTO MIDWEEK AS A STAGNANT NORTH-SOUTH MERIDIONAL FLOW PATTERN TRANSPORTS LARGE AMOUNTS OF TROPICAL MOISTURE NORTH INTO THE MIDDLE ATLANTIC AND NEW ENGLAND REGIONS. LATEST 12Z GEFS STANDARDIZED ANOMALY GRAPHICS CONTINUE TO ADVERTISE AN INCREASINGLY BLOCKY PATTERN WITH VERY AMPLIFIED HIGH PRESSURE DEVELOPING ACROSS THE INTERMOUNTAIN WEST WITH ADDITIONAL DOWNSTREAM RIDGING EXPECTED TO STRENGTHEN OVER TIME ACROSS THE NORTHERN ATLANTIC. AS HAS BEEN ADVERTISED OVER THE PAST FEW DAYS...VERY DEEP TROUGHING WILL DEVELOP WEST OF OUR FORECAST REGION WITH THE ASSOCIATED TROUGH AXIS EXPECTED TO EXTEND WELL SOUTH INTO THE GULF OF MEXICO BY EARLY WEEK. AS AN INDICATION OF HOW ANOMALOUS THE DEVELOPING PATTERN IS EXPECTED TO BE...LATEST WPC EXTENDED DISCUSSIONS NOW SPEAKING OF POSSIBLE ALL-TIME RECORD HIGHS ACROSS PORTIONS OF THE DESERT SOUTHWEST. MEANWHILE FOR AREAS CLOSER TO US...PWAT ANOMALY GRAPHICS ARRIVING THIS AFTERNOON SHOWING STRONG TROPICAL MOISTURE CONNECTIONS TO THE SOUTH ATLANTIC/CARIBBEAN...WITH AN ADDITIONAL COMPONENT EXPECTED TO ARRIVE FROM THE EAST-CENTRAL PACIFIC. THE CONVERGENCE OF BOTH LOW /MID-LEVEL AIR STREAMS WILL FUNNEL ITS WAY NORTH WITH TIME RESULTING IN WIDESPREAD RAIN/POTENTIALLY HEAVY RAIN DEVELOPMENT. A LITTLE TOO EARLY TO DIVE INTO EXACT DETAILS THIS FAR OUT BUT CONFIDENCE CONTINUES TO INCREASE THAT FLOODING RAINS ARE POSSIBLE SOMEWHERE ALONG THE ATLANTIC SEABOARD BEGINNING THIS WEEKEND AND LASTING THROUGH AT LEAST MIDWEEK. IN ANY EVENT...HAVE CONTINUED LIKELY POPS THROUGH THE PERIOD AND WILL CONTINUE TO ADVERTISE HEAVY RAIN POTENTIAL IN THE HWO PRODUCT. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... 18Z UPDATE... PRIMARILY VFR CONDS THROUGH MID TO LATE AFTN...WILL DETERIORATE INTO THE EARLY EVE PD...AS A LARGE AREA OF RAIN (OCNLY HVY) TRANSLATES NEWD INTO CNY/NE PA. THERE MAY BE EMBEDDED TSRA...BUT DUE TO UNCERTAIN COVERAGE/DVLPMT...WILL OPT TO LEAVE OUT OF THE FCST FOR THE TIME BEING. ATTM...IT LOOKS LIKE THE MOST PERSISTENT HVYR PCPN WILL BE AT KAVP/KBGM...AND PERHAPS KRME. WIDESPREAD LWR CLDS/FOG LATE AT NGT INTO EARLY FRI...WILL GRDLY IMPROVE BACK TO VFR TWDS LATE MRNG/MIDDAY. OUTLOOK...SAT THROUGH TUE... SAT THROUGH TUE... OCNL RESTRICTIONS ARE LIKELY EACH DAY...WITH SHRA/TSRA IN THE VICINITY. THE MOST PERSISTENT RESTRICTIONS MAY COME BY MON/TUE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR PAZ038>040-043- 044-047-048-072. NY...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ009-015>018- 022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...RRM NEAR TERM...CMG/RRM SHORT TERM...RRM LONG TERM...CMG/KAH/MLJ AVIATION...KAH/MLJ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
308 PM EDT THU JUN 27 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH FRIDAY NIGHT/... AS OF 1045 AM THURSDAY... MORNING STRATUS IS MIXING OUT..THOUGH WITH VARYING AMOUNTS OF CONVECTIVE DEBRIS CLOUDS ADVECTING EAST ACROSS THE AREA. CLOUD COVER MAY PERIODICALLY HINDER INSOLATION IN SOME AREAS...BUT ULTIMATELY EXPECT HIGHS WILL REACH FORECAST VALUES OF MID 80S WEST TO NEAR 90 IN THE SOUTHEAST. OF GREATER CONCERN IS THE APPROACHING UPPER-LEVEL TROUGH AND REMNANT CONVECTIVE VORTICITY JUST WEST OF THE MOUNTAINS. THE TROUGH AXIS WILL CROSS CENTRAL NC DURING PEAK HEATING TODAY...INTERACTING WITH A MODERATELY UNSTABLE AIRMASS (MLCAPE REACHING 1500-2000 J/KG) CHARACTERIZED BY DEWPOINTS IN THE UPPER 60S AND LOWER 70S...AS WELL AS PW OVER 1.75". FURTHER AIDING INSTABILITY WILL BE A POSSIBLE ELEVATED MIXED LAYER...EVIDENT ON THE 12Z KGSO RAOB. THE 850MB TEMP OF 21C LOOKS A BIT ANOMALOUS REGIONALLY...BUT THERE DOES APPEAR TO BE A STREAM OF WARMER 925-850MB ROUNDING THE BASE OF THE MEAN TROUGH AXIS OVER THE TN/OH VALLEY...SO THE POSSIBILITY OF A MODIFIED EML IS NOT DISCOUNTED. IN FACT...A 14Z AIRCRAFT SOUNDING AT KRDU HAS THE SAME THERMAL CHARACTER. 0-6KM EFFECTIVE SHEAR IS NOT PARTICULARLY STRONG THIS MORNING...BUT SHOULD INCREASE TO 20-30KT AS MID-LEVEL WINDS INCREASE AHEAD OF THE TROUGH. RAP SOUNDING EVEN SHOW A MODEST INCREASE IN SOUTHERLY LOW-LEVEL FLOW...WITH 0-1KM SHEAR APPROACHING 30KT AT KFAY BY 21-22Z. WHILE THE DETAILS OF HOW CONVECTION WILL EVOLVE ARE STILL A LITTLE UNCERTAIN...EXPECT DEVELOPMENT IN THE VICINITY OF THE LEE TROUGH OVER THE FOOTHILLS AND WESTERN PIEDMONT DURING THE NEXT FEW HOURS...WITH CLUSTERS OF CONVECTION GROWING UPSCALE AS THEY MOVES EASTWARD WITH THE UPPER TROUGH AND COLD POOL LATE THIS AFTERNOON AND EVENING. THE ENSEMBLE OF HI-RES MODELS SEEM TO FOCUS ON THE 19Z TO 01Z TIME FRAME...WITH BETTER SEVERE POTENTIAL EAST OF HWY 1. MAIN THREATS WILL BE DAMAGING WINDS AND LARGE HAIL. -BLS ONCE CONVECTION CLEARS THE AREA...CONDITIONS SHOULD BE QUIET OVERNIGHT...WITH LOWS IN THE UPPER 60S TO LOWER 70S. FRIDAY/FRIDAY NIGHT TO BE POSTED SHORTLY. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM THURSDAY... AN ANOMALOUSLY AMPLIFIED PATTERN WILL PREVAIL ACROSS THE CONUS THROUGH THE WEEKEND...CHARACTERIZED BY A DEEP UPPER LEVEL RIDGE OVER THE ROCKIES/INTERMOUNTAIN WEST AND DEEP TROUGHING EAST OF THE MISSISSIPPI...WITH A PERSISTENT UPPER LEVEL LOW CENTERED IN VICINITY OF THE LOWER GREAT LAKES AND OH VALLEY. ACROSS THE CAROLINAS AND MID-ATLANTIC...EXPECT ATYPICALLY STRONG SOUTHWEST FLOW ALOFT WITH NUMEROUS SMALL AMPLITUDE SHORTWAVES CROSSING THE REGION THROUGHOUT THE PERIOD IN THE PRESENCE OF A SEASONABLY MOIST AIRMASS. AS A RESULT...EXPECT ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS AND SLIGHTLY BELOW NORMAL HIGH TEMPS IN THE MID 80S...DEPENDING ON CLOUD COVER AND CONVECTION. THE EXACT COVERAGE AND PERSISTENCE OF CONVECTION WILL HIGHLY DEPEND ON THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT AND THE TIMING OF THESE DISTURBANCES IN RELATION TO THE DIURNAL HEATING CYCLE. FURTHERMORE...THE DEGREE OF DIURNAL DESTABILIZATION IS DIFFICULT TO ASCERTAIN GIVEN INCREASED CLOUD COVER AND AN ABOVE NORMAL CHANCE FOR NOCTURNAL OR EARLY MORNING CONVECTION...THOUGH ONE WOULD EXPECT AT LEAST SOME CLOUD BREAKS AND AREAS OF RELATIVELY STRONGER INSOLATION DURING PEAK HEATING. EITHER WAY...SLIGHTLY STEEPER MID-LEVEL LAPSE RATES /COOLER TEMPS ALOFT/ IN ASSOCIATION WITH THE UNUSUALLY AMPLIFIED UPPER LEVEL TROUGH OVER THE REGION WILL AT LEAST SOMEWHAT COMPENSATE FOR DECREASED INSOLATION. GIVEN DEEP-LAYER (0-6 KM) SHEAR LIKELY IN THE 35-45 KT RANGE...ORGANIZED CONVECTION WILL CERTAINLY BE POSSIBLE... INCLUDING SUPERCELLS...THOUGH THE TYPE/EXTENT OF ANY SEVERE THREAT CANNOT BE PRECISELY IDENTIFIED AT THIS TIME. IN ADDITION TO A POTENTIAL FOR SEVERE THUNDERSTORMS...ISOLATED FLASH FLOODING WILL ALSO BE POSSIBLE GIVEN RECENT HEAVY RAINFALL AND ABOVE NORMAL CHANCES FOR CONVECTION THROUGH THE WEEKEND. -VINCENT && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY... TO BE POSTED SHORTLY. -VINCENT && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 140 PM THURSDAY... SKIES ARE VARIABLY CLOUDY WITH VFR CONDITIONS ACROSS CENTRAL NC.N AN APPROACHING UPPER LEVEL TROUGH AND AND AN UNSTABLE AIRMASS WILL LEAD TO SCATTERED TO NUMEROUS SHOWERS AND STORMS THIS AFTERNOON AND EVENING. WHILE CONFIDENCE IN IS/WHEN STORMS WILL IMPACT INDIVIDUAL TERMINALS IS STILL LOW...PROBABILITIES WILL BE HIGHEST FROM KFAY TO KRWI WHERE HEATING AND MOISTURE AREA GREATEST TODAY. THE CHANCE OF OF STORMS SHOULD DECREASE SIGNIFICANTLY BY 00-03Z FROM WEST TO EAST. QUIET CONDITIONS WILL PREVAIL OVERNIGHT...WITH AT LEAST A CHANCE OF PATCHY STRATUS ACROSS PORTIONS OF EASTERN NC BASED ON FORECAST SOUNDINGS. OUTLOOK... UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT WEEK AS A DEEP UPPER LEVEL TROUGH SETS UP ACROSS THE EASTERN US. PERIODS OF SHOWERS AND STORMS CAN BE EXPECTED EACH AFTERNOON...WITH EARLY MORNING STRATUS OR FOG. && .EQUIPMENT... KRAX WSR-88D WILL BE DOWN FOR MUCH-NEEDED MAINTENANCE TODAY. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...CBL/BLS SHORT TERM...VINCENT LONG TERM...VINCENT AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
140 PM EDT THU JUN 27 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM THURSDAY... MORNING STRATUS IS MIXING OUT..THOUGH WITH VARYING AMOUNTS OF CONVECTIVE DEBRIS CLOUDS ADVECTING EAST ACROSS THE AREA. CLOUD COVER MAY PERIODICALLY HINDER INSOLATION IN SOME AREAS...BUT ULTIMATELY EXPECT HIGHS WILL REACH FORECAST VALUES OF MID 80S WEST TO NEAR 90 IN THE SOUTHEAST. OF GREATER CONCERN IS THE APPROACHING UPPER-LEVEL TROUGH AND REMNANT CONVECTIVE VORTICITY JUST WEST OF THE MOUNTAINS. THE TROUGH AXIS WILL CROSS CENTRAL NC DURING PEAK HEATING TODAY...INTERACTING WITH A MODERATELY UNSTABLE AIRMASS (MLCAPE REACHING 1500-2000 J/KG) CHARACTERIZED BY DEWPOINTS IN THE UPPER 60S AND LOWER 70S...AS WELL AS PW OVER 1.75". FURTHER AIDING INSTABILITY WILL BE A POSSIBLE ELEVATED MIXED LAYER...EVIDENT ON THE 12Z KGSO RAOB. THE 850MB TEMP OF 21C LOOKS A BIT ANOMALOUS REGIONALLY...BUT THERE DOES APPEAR TO BE A STREAM OF WARMER 925-850MB ROUNDING THE BASE OF THE MEAN TROUGH AXIS OVER THE TN/OH VALLEY...SO THE POSSIBILITY OF A MODIFIED EML IS NOT DISCOUNTED. IN FACT...A 14Z AIRCRAFT SOUNDING AT KRDU HAS THE SAME THERMAL CHARACTER. 0-6KM EFFECTIVE SHEAR IS NOT PARTICULARLY STRONG THIS MORNING...BUT SHOULD INCREASE TO 20-30KT AS MID-LEVEL WINDS INCREASE AHEAD OF THE TROUGH. RAP SOUNDING EVEN SHOW A MODEST INCREASE IN SOUTHERLY LOW-LEVEL FLOW...WITH 0-1KM SHEAR APPROACHING 30KT AT KFAY BY 21-22Z. WHILE THE DETAILS OF HOW CONVECTION WILL EVOLVE ARE STILL A LITTLE UNCERTAIN...EXPECT DEVELOPMENT IN THE VICINITY OF THE LEE TROUGH OVER THE FOOTHILLS AND WESTERN PIEDMONT DURING THE NEXT FEW HOURS...WITH CLUSTERS OF CONVECTION GROWING UPSCALE AS THEY MOVES EASTWARD WITH THE UPPER TROUGH AND COLD POOL LATE THIS AFTERNOON AND EVENING. THE ENSEMBLE OF HI-RES MODELS SEEM TO FOCUS ON THE 19Z TO 01Z TIME FRAME...WITH BETTER SEVERE POTENTIAL EAST OF HWY 1. MAIN THREATS WILL BE DAMAGING WINDS AND LARGE HAIL. -BLS ONCE CONVECTION CLEARS THE AREA... CONDITIONS SHOULD BE QUIET OVERNIGHT...WITH LOWS IN THE UPPER 60S TO LOWER 70S. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... AS OF 300 AM THURSDAY... MORE OF THE SAME IS EXPECTED FOR FRIDAY AS AFTERNOON/EVENING CONVECTION WILL DEVELOP ONCE AGAIN ACROSS THE REGION. HOWEVER... COVERAGE MAY BE SLIGHTLY LESS (WHEN COMPARED TO THURSDAY) AS CENTRAL NC WILL BE IN-BETWEEN TWO UPPER LEVEL TROUGHS AND THEREFORE DYNAMIC FORCING WILL BE WEAKER. NEVERTHELESS...AT THE SURFACE A LEE TROUGH WILL PROVIDE SUFFICIENT LOW LEVEL CONVERGENCE FOR THE DEVELOPMENT OF SCATTERED THUNDERSTORMS ACROSS THE FORECAST AREA AS A VERY MOIST AND UNSTABLE AIRMASS WILL STILL IN PLACE AND WEAK DISTURBANCES WILL LIKELY MOVE THROUGH THE REGION IN THE DEEP WESTERLY/SOUTHWESTERLY FLOW ALOFT. AS HAS BEEN THE CASE...THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING LOCALIZED FLOODING...SOME DAMAGING WIND GUSTS AND POSSIBLY SOME SMALL HAIL. WITH SLIGHTLY LESS IN THE WAY OF CONVECTIVE COVERAGE...HIGHS MAY BE A COUPLE OF DEGREES HIGHER THAN THURSDAY... GENERALLY WITHIN A DEGREE OR TWO ON EITHER SIDE OF 90. OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY... AN UNUSUALLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST THROUGH MUCH OF THE LONG TERM PERIOD AS A RIDGE BUILDS OVER THE WESTERN HALF OF THE CONUS (EXTENDING UP INTO CANADA)...WITH A DEEP TROUGH OVER THE EASTERN HALF. THIS TROUGH WILL BE CENTERED OVER THE OHIO VALLEY EARLY IN THE PERIOD...BEFORE RETROGRADING SLIGHTLY THROUGH EARLY/MID NEXT WEEK. REGARDLESS...THIS PATTERN WILL LEAVE CENTRAL NC WITHIN A VERY MOIST AIR MASS AS DEEP SOUTHWESTERLY FLOW PERSISTS. AS A RESULT...UNSETTLED WEATHER WILL CONTINUE THROUGH THE ENTIRE LONG TERM PERIOD (IF NOT LONGER) ACROSS CENTRAL NC...WITH ABOVE NORMAL CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY. A COUPLE OF NOTES ABOUT PRECIP CHANCES...ON SATURDAY SOME SLIGHTLY DRIER AIR IS PROGGED TO MOVE INTO THE WESTERN PORTIONS OF THE FORECAST AREA (AS A SURFACE FRONT NUDGES INTO THE REGION) AND THIS COULD HOLD DOWN PRECIP CHANCES ACROSS THAT PART OF THE FORECAST AREA. HOWEVER...MOISTURE QUICKLY RETURNS LATE SATURDAY AND THE BRIEF LULL IN PRECIP SHOULD END. THEN...AS THE UPPER LEVEL TROUGH RETROGRADES SOME TO BEGIN THE WEEK...THE RIDGE OVER THE WESTERN ATLANTIC WILL ALSO RETROGRADE...THEREFORE EVENTUALLY EXERTING SOME MORE INFLUENCE OVER THE REGION BY THE MIDDLE OF THE WEEK. THIS IS WHEN WE MAY START SEEING A DECREASE IN PRECIP COVERAGE...ESPECIALLY OVER EASTERN NC. OTHERWISE...WITH INCREASING FLOW ALOFT...THE SHEAR WILL IMPROVE OVER THE AREA (ESPECIALLY ACROSS THE NORTH AND WEST THROUGH MONDAY AS THE AFOREMENTIONED TROUGH IS CLOSEST TO THE REGION) AND THEREFORE WE SHOULD SEE MORE IN THE WAY OF ORGANIZED CONVECTION OVER THE WEEKEND. THIS MAY RESULT IN SOME STRONG TO SEVERE STORMS...WITH DAMAGING WIND GUSTS BEING THE PRIMARY THREAT. HOWEVER...A SIGNIFICANT WEATHER THREAT WILL LIKELY BE THE INCREASING FLOODING RISK AS THE AREA REMAINS IN THIS EXTENDED WET PATTERN. DAYTIME HIGHS WILL GENERALLY BE BELOW NORMAL THROUGH THE PERIOD...WITH MOSTLY MID 80S EXPECTED. OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 140 PM THURSDAY... SKIES ARE VARIABLY CLOUDY WITH VFR CONDITIONS ACROSS CENTRAL NC.N AN APPROACHING UPPER LEVEL TROUGH AND AND AN UNSTABLE AIRMASS WILL LEAD TO SCATTERED TO NUMEROUS SHOWERS AND STORMS THIS AFTERNOON AND EVENING. WHILE CONFIDENCE IN IS/WHEN STORMS WILL IMPACT INDIVIDUAL TERMINALS IS STILL LOW...PROBABILITIES WILL BE HIGHEST FROM KFAY TO KRWI WHERE HEATING AND MOISTURE AREA GREATEST TODAY. THE CHANCE OF OF STORMS SHOULD DECREASE SIGNIFICANTLY BY 00-03Z FROM WEST TO EAST. QUIET CONDITIONS WILL PREVAIL OVERNIGHT...WITH AT LEAST A CHANCE OF PATCHY STRATUS ACROSS PORTIONS OF EASTERN NC BASED ON FORECAST SOUNDINGS. OUTLOOK... UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT WEEK AS A DEEP UPPER LEVEL TROUGH SETS UP ACROSS THE EASTERN US. PERIODS OF SHOWERS AND STORMS CAN BE EXPECTED EACH AFTERNOON...WITH EARLY MORNING STRATUS OR FOG. && .EQUIPMENT... KRAX WSR-88D WILL BE DOWN FOR MUCH-NEEDED MAINTENANCE TODAY. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...CBL/BLS SHORT TERM...KRR LONG TERM...KRR AVIATION...BLS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1245 PM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 1245 PM CDT THU JUN 27 2013 THUNDER CHANCES AND WIND SPEEDS WILL BE THE CONCERN. FORECAST THINKING REMAINS ON TRACK AFTER LOOKING AT 15Z RAP/HRRR AND 12Z MODELS. 15Z HRRR CONTINUES TO SHOW ISOLD SHOWERS THIS AFTERNOON ACROSS NE NORTH DAKOTA INTO WEST CENTRAL MINNESOTA (WHICH IS OUTSIDE OF OUR CURRENT FORECASTED POPS). LAPS ANALYSIS INDICATES MLCAPE 500-700 J/KG WITHIN THIS AREA...SO ISOLD SHOWER/THUNDER IS POSSIBLE AND WILL ADD TO THE FORECAST FOR THIS AFTERNOON. THE BETTER SHOWER/THUNDER CHANCES STILL REMAIN ACROSS THE NE FA WHICH IS CLOSER TO THE UPPER LOW/TROUGH. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 338 AM CDT THU JUN 27 2013 UPPER LOW OVER MANITOBA NEAR BERENS RIVER WILL DROP SOUTHEAST TODAY TOWARD THE BOUNDARY WATER REGION ALONG MINNESOTA/ONTARIO FOR TONIGHT. SHORT WAVE WHICH CAUSED SCT STORMS TO MOVE THRU NE ND/NW MN AS MOVED EAST WITH STORMS NOW OVER NE MN. AS UPPER LOW MOVES SOUTHEAST EXPECT A RE-GENERATION OF SCATTERED THUNDERSTORMS OVER NW MN IN COOL POCKET ALOFT. SOUNDINGS SHOW STEEP LAPSE RATES AND NEGATIVE LIFTED INDICES IN REGION. WILL MAINTAIN IDEA OF CHC POPS HALLOCK-PARK RAPIDS NORTH AND EAST WITH REST OF THE FCST AREA SEEING SOME DIURNAL CU FORMATION WITH DAYTIME HEATING. STILL WARM TODAY...WITH MOST SITES IN THE LOWER TO MID 80S. WILL MAINTAIN SOME POPS FOR ISOLD/SCT TRW IN NW MN THRU TONIGHT AS LIKE WED NIGHT COULD SEE A FEW STORMS LAST WELL PAST SUNSET DUE TO DYNAMICS ALOFT. LOOKS BREEZY-WINDY TODAY WITH WEST-NORTHWEST WINDS GUSTING TO 25 KTS OR SO IN THE AFTN. BROAD UPPER TROUGH WILL SETTLE SOUTHWARD FRIDAY SPREADING THE RISK OF A FEW SHOWERS/STORMS FARTHER WEST INTO ERN ND DURING THIS TIME PERIOD...THOUGH MAIN CHC WILL REMAIN IN NORTHWEST INTO CENTRAL MN. LOOK FOR A DROP OF 2-4C IN 850 MB TEMPS ALONG WITH INCREASE IN OVERALL CLOUD COVER FRI. THIS WILL GIVE HIGH TEMPS ABOUT 5 DEG COOLER BOTH DAYS WITH HIGHS MOSTLY IN THE 70S. ANOTHER BREEZY- WINDY DAY WITH GUSTS OVER 25 KTS AT TIMES FROM THE NORTHWEST. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 338 AM CDT THU JUN 27 2013 UPPER TROUGH WILL CONTINUE TO SLOWLY DROP SOUTH FRI NIGHT-SAT AND WILL KEEP RISK OF A FEW SHOWERS/STORMS THRU THIS PD...WITH BEST CHC IN MINNESOTA PART OF THE FCST AREA. BY LATE SAT MAIN THREAT SHIFTS SOUTH INTO CNTRL-SRN MN. WITH COOLING AT 850 MB SATURDAY WILL SEE HIGHS ONCE AGAIN IN THE 70S. FOR SUNDAY THROUGH WEDNESDAY...00 UTC GFS/ECMWF IN REASONABLE AGREEMENT THROUGH 00 UTC TUESDAY... DIVERGING THEREAFTER. BOTH SHOW A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS AND A BROAD TROUGH CENTERED ACROSS THE OHIO RIVER VALLEY...PLACING THE FORECAST AREA IN NORTHWEST FLOW ALOFT. MODEL DIFFERENCES EMERGE LATE MONDAY THROUGH MID-WEEK WITH THE INTERACTION BETWEEN A SOUTHWARD PROPAGATING CANADIAN SHORT-WAVE AND THE BROADER TROUGH TO THE SOUTH. BOTH MODELS SUGGEST THESE FEATURES WILL MERGE SOMEWHERE ACROSS THE MIDWEST/CENTRAL PLAINS BY WEDNESDAY...BUT DETAILS ARE SKETCHY AT THIS TIME. FOR NOW...WILL KEEP ALL BLEND CHANCE POPS MONDAY NIGHT THROUGH WEDNESDAY...ALTHOUGH THIS PAINTS AN OVERALL POTENTIAL FOR WETTER CONDITIONS THAN WHAT IS EXPECTED. IT DOES APPEAR LIKELY THAT THE FORECAST AREA WILL REMAIN ON THE COOL-SIDE OF THE MID-LEVEL THERMAL GRADIENT BETWEEN THE RIDGE TO THE WEST AND TROUGH TO THE EAST. THIS SHOULD KEEP TEMPERATURES NEAR SEASONAL NORMALS WITH HIGHS IN THE MID 70S TO LOWER 80S AND LOWS IN && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1245 PM CDT THU JUN 27 2013 DRY FCST EXCEPT FOR KBJI FROM MID AFTERNOON THROUGH EVENING WHERE LINGERING UPPER LOW COULD INSTIGATE SCT TSTM ACTIVITY. GUSTY CHARACTER OF NW WNDS TO DIMINISH TWD SUNSET...ENOUGH GRADIENT WILL KEEP SPEEDS ABOVE 10 KTS THOUGH. TROUGH TO NORTHEAST TO MOVE BACK TOWARD KBJI-KTVF OVERNIGHT...BRINGING LOW VFR DECK TO THOSE SITES. && .HYDROLOGY... ISSUED AT 1245 PM CDT THU JUN 27 2013 RUNOFF CONTINUES TO MAKES ITS WAY INTO THE RED RIVER FROM AREA TRIBUTARIES. ONLY MINOR UPDATES WERE MADE TO MOST RIVER FORECAST POINTS THIS MORNING. THE RED RIVER AT FARGO IS FORECAST TO CREST NEAR MAJOR FLOOD STAGE TOWARDS LATE FRIDAY OR FRIDAY NIGHT. RISES ARE EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS ON CENTRAL AND NORTHERN SECTIONS OF THE RED WITH A FEW FORECAST POINTS EXPECTED TO RISE ABOVE MINOR FLOOD STAGE. THE RIVER FLOOD WARNING FOR WAHPETON WAS CANCELLED AS RIVER LEVELS CONTINUE TO FALL. HOWEVER EXPECTED RELEASES FROM WHITE ROCK DAM MAY SLOW THE RECESSION OF RIVER LEVELS. THE FLOOD ADVISORY FOR CASS CO AND THE AREAL FLOOD WARNING FOR PARTS OF WILKIN...CLAY AND RICHLAND COUNTIES WAS ALLOWED TO EXPIRE. CONDITIONS HAVE MARKEDLY IMPROVED OVER THE PAST 24 HOURS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...RIDDLE LONG TERM...RIDDLE/ROGERS AVIATION...WJB HYDROLOGY...MAKOWSKI
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1227 PM CDT THU JUN 27 2013 .UPDATE... ISSUED AT 1227 PM CDT THU JUN 27 2013 SUNNY SKIES AREA WIDE EARLY THIS AFTERNOON. MAY SEE A FEW CU DEVELOP...BUT OVERALL EXPECT SKY COVER TO REMAIN LOW. WINDS ARE GUSTING TO AROUND 30 MPH AT TIMES...AND WILL CONTINUE TO DO SO THROUGH EARLY THIS EVENING BEFORE SUBSIDING. OVERALL...CHANGES WERE MINOR FOR THE EARLY AFTERNOON FORECAST PACKAGE. UPDATE ISSUED AT 933 AM CDT THU JUN 27 2013 ONLY MINIMAL CHANGES WERE MADE FOR THIS MID MORNING FORECAST UPDATE. INCREASED WINDS JUST A BIT...ESPECIALLY SOUTHWEST...WHERE LATEST GUIDANCE INDICATES A FEW GUSTS TO 30KTS AT TIMES. OTHERWISE...SHOULD BE A DRY/SUNNY/WARM DAY WITH A STEADY NORTHWEST WIND...BREEZY AT TIMES. UPDATE ISSUED AT 640 AM CDT THU JUN 27 2013 PLEASANT MORNING WEATHERWISE ACROSS THE AREA WITH MOSTLY CLEAR SKIES. SOME HIGH CLOUDS EVIDENT ACROSS THE SOUTH...BUT THESE CLOUDS CONTINUE TO PUSH INTO SOUTH DAKOTA. NO CHANGES TO THE FORECAST OTHER THAN FRESHENING UP THE NEAR TERM HOURLY FORECASTS. BREEZY NORTHWEST WINDS WILL DEVELOP BY MID MORNING WITH WARM TEMPERATURES INTO THE 80S EXPECTED TODAY BEFORE A SLIGHT COOL DOWN OCCURS FRIDAY INTO THE WEEKEND. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT THU JUN 27 2013 SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM FOR TODAY. HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE. HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE. HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT. WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A CLEAR AND QUIET NIGHT EXPECTED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 330 AM CDT THU JUN 27 2013 NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST. MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20 KTS. AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT TO TIME AT THIS POINT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1227 PM CDT THU JUN 27 2013 VFR CONDITIONS ALL TERMINALS FOR THE 18Z PERIOD. BREEZY NORTHWEST WINDS EXPECTED THROUGH SUNSET...WITH GUSTS UP TO AROUND 25 KTS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...AYD LONG TERM...JNS AVIATION...NH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1242 PM CDT THU JUN 27 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 318 AM CDT THU JUN 27 2013 CURRENTLY SEEING SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP ACROSS SOUTH CENTRAL AND SOUTHEAST SOUTH DAKOTA. THESE APPEAR TO BE BASED ALONG AN AREA OF CONVERGENCE WAY UP AT 600 MB. THUS PROBABLY NOT MUCH IN THE WAY OF RAIN REACHING THE GROUND...ALTHOUGH A FEW HUNDREDTHS OF AN INCH ARE POSSIBLE. CAPE ONLY AROUND 100-200 J/KG...THUS NOT EXPECTING THESE TO INTENSIFY MUCH...WITH JUST PERIODIC LIGHTNING STRIKES. MAY SEE ACTION INTENSIFY MORE TOWARDS THE MISSOURI RIVER CLOSER TO 10Z. AS THE LOW LEVEL JET CONTINUES TO INCREASE THIS REGION WILL BE IN A PRETTY GOOD AREA OF CONVERGENCE IN THE 700 TO 800 MB LAYER. BEING LOWER BASED THESE SHOWERS WILL HAVE A BIT MORE CAPE TO WORK WITH AND HAVE A BETTER CHANCE OF PRODUCING A PERIOD OF STEADY RAINFALL. HRRR SEEMS TO BE HANDLING THINGS PRETTY WELL...AND ALSO SUGGESTS COVERAGE AND INTENSITY OF THE STORMS SHOULD INCREASE AFTER 10Z IN THE MISSOURI RIVER CORRIDOR FROM BON HOMME COUNTY SOUTHEAST INTO PORTIONS OF NORTHWEST IOWA AND NORTHEAST NEBRASKA. CAPE WILL REMAIN TOO LOW FOR ANY SEVERE THREAT...BUT AN INCREASE IN LIGHTNING ACTIVITY AND BRIEF HEAVY RAIN SEEM PROBABLE. THIS ACTIVITY SHOULD DISSIPATE AND PUSH SOUTHEAST OF OUR CWA BY 18Z...GIVING WAY TO INCREASING SUNSHINE. HIGHS WILL BE PRETTY SIMILAR TO YESTERDAY...MAYBE A DEGREE OR TWO COOLER IN SPOTS...ESPECIALLY IF CLOUD CLOVER HANGS AROUND A BIT LONGER. BUT OVERALL...AN ABOVE NORMAL TEMPERATURE DAY WITH HIGHS IN THE MID 80S TO AROUND 90 EXPECTED. HUMIDITY LEVELS WILL ALSO BE PRETTY SIMILAR TO YESTERDAY...MAYBE A TOUCH LOWER BY AFTERNOON. WILL BE A BIT ON THE BREEZY SIDE BY AFTERNOON...ESPECIALLY ACROSS THE NORTHEAST HALF OF THE AREA...WITH WINDS GUSTING INTO THE 20 TO 30 MPH RANGE OUT OF THE NORTHWEST. EXPECTING CLEAR SKIES TONIGHT WITH A LIGHT NORTHWESTERLY BREEZE. LOWS SHOULD RUN A COUPLE DEGREES ABOVE AVERAGE...ABOUT 60 TO 65 ACROSS THE AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 318 AM CDT THU JUN 27 2013 FRIDAY LOOKS DRY...WARM AND WINDY WITH NORTHWEST WINDS AVERAGING ABOUT 20 TO 30 MPH IN THE EASTERN CWA. OTHERWISE EXPECTING HIGHS IN THE 80S. SATURDAY WILL SEE COOLER AIR CONTINUE TO WRAP INTO THE REGION AND SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE DURING PEAK HEATING. SOUNDING ANALYSIS SUGGESTS ONLY SKINNY CAPE...AND NOT MUCH OF IT...AVAILABLE FOR UPDRAFT STRENGTH SO NOT PLANNING ON SEVERE. LOOKS A BIT CAPPED IN THE WEST AS WELL SO WILL HAVE POPS MAINLY FROM INTERSTATE 29 EAST. WITH CLOUDS COMING IN LOWERED HIGHS A LITTLE...ESPECIALLY IN THE EAST WHERE 70 TO 75 WILL LIKELY BE THE MAX WHILE CENTRAL SOUTH DAKOTA COULD REACH 80. ANY CHANCE FOR SHOWERS SHOULD QUICKLY DIMINISH WITH PEAK HEATING SO NOT PLANNING ON ANYTHING IN THE EVENING. A GRADUAL DECREASE IN CLOUDS AND WIND WILL ALSO ALLOW FOR A COOL OVERNIGHT LOW...GENERALLY IN THE MID 50S. FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME...THE VARIOUS MODELS CONTINUE TO CONVERGE AND A COOL AND MOSTLY DRY WEATHER PATTERN. MODEL TRENDS FOR THE THIRD DAY ION A ROW PUSH THE RIDGE OVER THE ROCKIES EVEN FARTHER WEST WHILE A TROUGH OF LOW PRESSURE AND ASSOCIATED COOLER THERMAL FIELD SETTLE INTO THE PLAINS STATES...WHICH JUST A COUPLE OF DAYS AGO LOOKED LIKE WOULD BE OVER THE MIDWEST WITH THE PLAINS IN MORE OF A DRY MIXY PATTERN ON THE EDGE OF AN UPPER LEVEL RIDGE. OVERALL SUSPECT THAT HIGHS WILL BE IN THE 70S AND LOWS WILL BE IN THE 50S. PLEASANT WEATHER BUT A BIT ON THE COOL SIDE FOR THOSE LOOKING AT LAKE AND SWIMMING POOL ACTIVITIES. ONE PERIOD WITH THE POTENTIAL TO BE THE COOLEST AND POSSIBLY SEE SOME RAIN SHOWERS WILL BE WEDNESDAY WHERE BOTH THE GFS AND ECMWF SWING SOME UPPER LEVEL SUPPORT SOUTHWARD WITH INCREASING MID AND UPPER LEVEL MOISTURE. IF IT WERE TO CLOUD UP QUICKLY ON WEDNESDAY AND RAIN HIGH TEMPERATURES MAY BARELY CREEP INTO THE 70S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1242 PM CDT THU JUN 27 2013 VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS COULD GET A LITTLE GUSTY OUT OF THE NORTHWEST THIS AFTERNOON AS SURFACE TEMPERATURES WARM ENOUGH TO ALLOW FOR DEEPER MIXING. ANY GUSTS WILL GENERALLY BE LESS THAN 20KT...AND SHOULD SUBSIDE QUICKLY BETWEEN 00Z-01Z THIS EVENING. STRONGER GUSTS IN THE 20-30KT RANGE EXPECTED TO DEVELOP BY MID MORNING FRIDAY. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...08 AVIATION...JH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 331 PM CDT THU JUN 27 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 100KT JET STREAK DIVING INTO THE WESTERN GREAT LAKES AS THE SOUTHWEST SUB- TROPICAL RIDGE BUILDS NORTHWARD. VARIOUS SHORTWAVE IMPULSES FROM SOUTHERN MANITOBA TO THE UPPER PENINSULA COMBINED WITH INCREASING INSTABILITY AROUND 1500 J/KG ARE TRIGGERING SCATTER SHOWERS AND THUNDERSTORMS. MANY STORMS HAVE BEEN FLIRTING WITH SEVERE LEVELS...WHICH SHOULD CONTINUE THROUGH EARLY THIS EVENING. PRIMARY UPPER TROUGH OVER SOUTHEAST MANITOBA WILL BE DROPPING INTO THE REGION TOMORROW. THE MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE WEATHER FOR THE REST OF TODAY AND PRECIP TOMORROW. TONIGHT...CHANNELED VORTS ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET WILL BE DIVING SOUTHEAST THIS EVENING ACROSS NORTHERN WISCONSIN. AMPLE INSTABILITY AROUND 1.5K J/KG COMBINED WITH THIS FORCING ALOFT SHOULD BE ABLE TO SUSTAIN STORMS INTO EASTERN WISCONSIN LATER THIS AFTERNOON AND THIS EVENING. AS THE JET STREAK SHIFTS A LITTLE SOUTH AND THE UPPER LOW MOVES OVER LAKE SUPERIOR...0-6KM BULK SHEAR VALUES WILL BE DROPPING THIS EVENING. COMBINED WITH LOSS OF INSTABILITY...SHOULD SEE STORMS DIMINISH IN INTENSITY BY MID EVENING. STILL SOME SHOWERS COULD POP UP THROUGH THE NIGHT OVER NORTH-CENTRAL TO NORTH-EAST WISCONSIN AND WILL LEAVE SMALL POPS IN THE FORECAST FOR THE REST OF THE NIGHT. LOWS IN THE 50S AND 60S. FRIDAY...THE UPPER LOW OVER LAKE SUPERIOR WILL DROP SOUTHEAST ACROSS THE CENTRAL GREAT LAKES. AS THIS OCCURS...A DEEP TROUGH WILL DROP ACROSS THE STATE WHICH SHOULD BRING SHOWERS AND STORMS TO NORTHERN WISCONSIN DURING THE MORNING. ADDITIONAL STORMS ARE LIKELY IN THE AFTERNOON WITH HELP FROM DIURNAL INSTABILITY. WITH THE CLOUD COVER AND COOLER TEMPS...NOT ANTICIPATING ANY SEVERE STORMS AT THIS TIME. A MOSTLY CLOUDY DAY WITH HIGHS IN THE UPPER 60S TO MID 70S. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 331 PM CDT THU JUN 27 2013 FOR THE EARLY PORTION OR THROUGH SATURDAY...CONVECTION WILL MAINLY BE ASSOCIATED WITH THE SOUTHWARD PASSAGE OF THE TROUGH AXIS. PCPN WILL BE ON THE DECREASE FROM NORTH TO SOUTH ON SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH. COOLER DRIER AIR WILL FILTER INTO THE STATE ON NORTH WINDS AS A LARGE HIGH PRESSURE SYSTEM SETTLES INTO THE NORTHERN PLAINS AND GREAT LAKES REGION. PROBLEM OR CHALLENGE WITH THE LATER PERIODS CONCERN ORIENTATION OF THE RETROGRADING DEEP UPPER TROUGH OR UPPER LOW OVER THE SURFACE HIGH PRESSURE. H5 TEMPS PROGGED TO BE ONLY IN THE -12 C RANGE ABOVE THE SURFACE HIGH...SO NOT REALLY A COOL AIR MASS ALOFT TO SUPPORT INSTABILITY AFTERNOON PCPN...SO WILL LEAVE THE SHOWER MENTION OUT OF THE LATER PERIODS FOR NOW...BUT CANNOT RULE OUT VERY ISOLATED SHOWER ACTIVITY. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1234 PM CDT THU JUN 27 2013 SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON ACROSS MOST OF NORTH-CENTRAL AND NORTHEAST WISCONSIN. ANY THUNDERSTORMS WILL HAVE POTENTIAL TO CREATE STRONG GUSTY WINDS AND NEAR SEVERE HAIL. STORMS WILL CONTINUE TO MID TO LATE EVENING BEFORE DISSIPATING. THEN AN UPPER LEVEL LOW PRESSURE SYSTEM WILL DROP SOUTH ACROSS THE REGION LATE TONIGHT INTO SATURDAY. STATISTICAL GUIDANCE AND PROGGED SOUNDINGS SHOW CIGS FALLING TO MVFR LEVELS TOMORROW MORNING AND FAIRLY WIDESPREAD SHOWER ACTIVITY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TDH AVIATION.......MPC