Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 292355 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 755 PM EDT TUE JUL 29 2014 .SYNOPSIS... UNSEASONABLY COOL TEMPERATURES WILL CONTINUE THROUGH THE WEEK ALTHOUGH SOME SLOW MODERATION IS LIKELY EACH DAY AS A LARGE TROUGH OF LOW PRESSURE OVER THE EASTERN UNITED STATES REMAINS THE PRIMARY FEATURE DRIVING THE DAILY WEATHER. IN FACT...THE TROUGH WILL RETROGRADE WESTWARD AND WEAKEN DURING THE REMAINDER OF THE WEEK WHICH EVENTUALLY WILL LEAD TO INCREASED WARMTH AND HUMIDITY BY THE END OF WEEK...BUT BY JULY STANDARDS IT WILL STILL FEEL QUITE COMFORTABLE THROUGH FRIDAY. SEVERAL DISTURBANCES ROTATING THROUGH THE TROUGH WILL BRING THREATS FOR AFTERNOON AND EARLY EVENING SHOWERS AND ISOLATED THUNDERSTORMS...TONIGHT...TOMORROW AND THURSDAY. WEDNESDAY WILL SEE THE HIGHEST PROBABILITIES OF RAINFALL. WHILE TEMPERATURES WILL REMAIN BELOW NORMAL INTO THE WEEKEND...THEY WILL WARM INTO THE LOWER 80S WITH A CONTINUED THREAT FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY ON SATURDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 500MB NEGATIVE ANOMALY /TO 4 STANDARD DEVIATIONS BELOW LATE JULY CLIMO/ REMAINS CENTERED OVER THE EASTERN UNITED STATES IN THE FORM OF AN UNSEASONABLY DEEP/STRONG LONGWAVE TROUGH. THE -4 SIGMA HEIGHT ANOMALY IS ACTUALLY CENTERED IN THE CAROLINAS /WITH RESPECT TO CLIMATOLOGY/ AND WITH 850MB TEMPS SUBSEQUENTLY 2 TO 3 STANDARD DEVIATIONS FROM CLIMO ACROSS OHIO/KY...IT IS NO SURPRISE THAT RECORD LOW MAX TEMPS FOR TUESDAY JULY 29TH ARE BEING THREATENED. A RENEWED BURST OF MID LEVEL COLD ADVECTION OWING TO A WEAK SHORTWAVE TROUGH IS DRIVING A WEAK SURFACE TROUGH AND SCT-BKN LINE OF CONVECTION ACROSS SRN LOWER MI/NRN INDIANA AT THE PRESENT /20Z/. THIS IS TIED VERY STRONGLY TO THE DIURNAL CYCLE DESPITE SOME MEAGER MID/UPPER LEVEL SUPPORT...AND HI-RES GUIDANCE /29.00Z SSEO/ IS IN GOOD AGREEMENT THAT SHRA/ISOLD TSRA WILL BEGIN TO DIMINISH PAST 00Z AS IT MOVES INTO SERN IND/WRN OH. UNTIL THEN...IT SHOULD MAINTAIN INTO AT MINIMUM WEST CENTRAL OHIO BY 23Z. OBJECTIVE ANALYSIS INDICATES MLCAPE TO 500 J/KG JUST TO THE WEST WHERE ACTIVITY IS LOCATED AND WEAK DEEP SHEAR /20KTS/ THUS THINK ACTIVITY IS JUST ABOUT AT MAXIMUM OR WILL BE SO IN NEXT HOUR AS IT CROSSES ERN IND BEFORE IT STARTS TO CYCLE DOWN THROUGH THE EARLY/MID EVENING. FOR LOW TEMPS TONIGHT WENT A FEW DEGREES WARMER THAN LAST NIGHT BUT STILL WELL BELOW NORMAL. DAILY RECORDS FOR THE 30TH /MIN TEMP/ SHOULD BE SAFE AT ALL CLIMATE SITES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... DECENT JET STREAK /SEEN NICELY ON 2.0 PV SURFACE/ DIGGING DOWN THE WEST SIDE OF THE DEEP ERN CONUS LONGWAVE TROUGH WILL QUICKLY TRANSLATE THROUGH THE GREAT LAKES ON WEDNESDAY. THIS IS ALREADY RESPONSIBLE FOR STORMS IN NRN MN/WRN LAKE SUPERIOR AND IS ENHANCING/STEEPENING THE DEEPER LAYER LAPSE RATES AMIDST INCREASING MOISTURE. THINK ARRIVAL OF THE LEFT EXIT REGION OF THIS JET STREAK OVER THE AREA AROUND LATE MORNING/AFTN WILL INITIATE A MORE /RELATIVELY/ CONCENTRATED AREA OF SHOWERS AND STORMS...AGAIN WITH DIURNAL ENHANCEMENT. FORECAST SOUNDINGS /29.12Z NAM AND GFS/ SUGGEST MLCAPE SHOULD RANGE FROM 300-700 J/KG ACROSS THE AREA WITH A RATHER STEEP BUT RELATIVELY MOIST LAPSE RATE - SHOULD BE EFFICIENT FOR GENERATING SHRA/STORMS GIVEN THE UPPER LEVEL SUPPORT. CONSIDERED WIDESPREAD RAIN CHANCES IN PEAK HEATING /PER 29.09Z SREF PROBABILITIES/ BUT DIALED BACK A LITTLE BASED ON 29.12Z HIRES-ARW WRF WHICH IS MORE REFINED AND TRACKS SEVERAL SMALL CLUSTERS OF STORMS ACROSS THE AREA. WITH INSTBY...COLD MID LEVEL TEMPS /-16C AT 500MB AND LOW WBZ HEIGHTS/ AND WHAT SHOULD BE SOME MODEST DIABATIC HEATING BEFORE CUMULUS ERUPTS...SOME SMALL HAIL CERTAINLY SEEMS LIKELY IN THE STRONGER CORES WED AFTN. DEEPER SHEAR STILL WEAK /20-25KTS OF UNIDIRECTIONAL NWLY FLOW/...SO WHILE A ROGUE SEVERE STORM POSSIBLE THINK INSTBY WILL LIMIT THIS POTENTIAL. IT DOES BEAR MENTIONING THAT 29.12Z NAM SOUNDINGS WERE BY FAR THE MOST UNSTABLE OF ANY PREVIOUS RUN OR ANY SREF/GFS MEMBER OR RUN IN THE PAST FEW DAYS...SO IF THAT BEARS TRUE /MLCAPE IN EXCESS OF 1000 J/KG OVER NRN CWA/ WE MAY HAVE A FEW MORE STRONG CORES THAN CURRENTLY THINKING. BUT AS OF NOW THROWING OUT THAT MORE UNSTABLE THINKING BASED ON LACK OF AGREEMENT IN OTHER DATA. DID INCREASE RAIN CHANCES QUITE A BIT...AND MAY NEED FURTHER ENHANCEMENT IN THE NORTHERN CWA WHERE JET INFLUENCE AND DIURNAL INSTBY WILL BE MAXIMIZED. ACTIVITY SHOULD DWINDLE QUICKLY AS AVAILABLE INSTBY IS TURNED OVER AND PBL DECOUPLES WED EVENING. ANOTHER COOL NIGHT IN THE 50S...BUT WARMER OVER PREVIOUS NIGHTS. THURSDAY...A SIMILAR STORY...AS LONGWAVE TROUGH AXIS RETROGRADES SLOWLY WESTWARD AS ATLANTIC RIDGING BULGES NORTH AND INCREASES. THIS SHOULD KEEP MINIMAL INSTBY /THOUGH MUCH LOWER THAN WED/ AND POTENTIAL FOR WEAK DISTURBANCES ROTATING THROUGH THE LONGWAVE TROUGH TO COMBINE FOR SMALL DIURNALLY DRIVEN SHOWER/STORM CHANCES. AS HEIGHTS SLOWLY RISE WITHIN THE TROUGH...ADDING A FEW DEGREES ONTO EACH DAYS HIGH TEMP FOR WED AND THURSDAY...GETTING US BACK TOWARD 80 DEGREES BY THE END OF THE WORK WEEK. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AN UPPER LEVEL TROUGH WILL BE IN PLACE ACROSS THE AREA FROM FRIDAY THROUGH THE WEEKEND. MULTIPLE DISTURBANCES WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS OFF AND ON THROUGH THE WEEKEND. THE GREATEST CHANCE FOR PRECIPITATION WILL BE DURING THE DAY ON SATURDAY. BELOW NORMAL HIGH TEMPERATURES CAN BE EXPECTED THROUGH THE WEEKEND WITH THIS TROUGH IN PLACE. THIS FEATURE WILL BEGIN TO MOVE EAST OF THE AREA ON MONDAY ALLOWING FOR DAY CONDITIONS. A WEAK DISTURBANCE WILL MOVE ACROSS NORTHERN PORTIONS OF THE FA ON TUESDAY ALLOWING FOR A CHANCE OF THUNDERSTORMS ACROSS THE NORTH. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... CONDITIONS ARE FORECAST TO BE VFR THROUGH THE TAF PERIOD WITH THE POSSIBLE EXCEPTION OF SOME MIST AT KLUK TOWARDS 12Z. CLOUDS ASSOCIATED WITH WEAKENING SHOWERS WILL PASS ACROSS THE REGION EARLY IN THE PERIOD. THEN EXPECT FEW IF ANY CLOUDS OVERNIGHT. WITH HEATING ON WEDNESDAY BROKEN CEILINGS WILL DEVELOP. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP IN THE AFTERNOON AND POTENTIALLY AFFECT TAF SITES...ESPECIALLY FROM KDAY TO KCMH/KLCK. BUT PROBABILITY THAT FAR OUT IN TIME PRECLUDES MENTION IN THE TAFS AT THIS POINT. OUTLOOK...THUNDERSTORMS POSSIBLE FRIDAY AND SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU SHORT TERM...BINAU LONG TERM...NOVAK AVIATION...

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