Area Forecast Discussion
Issued by NWS Wilmington, OH

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KILN 211331 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 931 AM EDT THU AUG 21 2014 .SYNOPSIS... A WARM FRONT WILL GRADUALLY LIFT NORTHEAST INTO THE GREAT LAKES THROUGH SATURDAY...THEN CONTINUE TO WAVER ACROSS THE REGION THROUGH THE BEGINNING OF NEXT WEEK. DISTURBANCES IN NORTHWEST FLOW ALOFT WILL INTERACT WITH A VERY WARM AND MOIST AIRMASS TO PRODUCE SHOWERS AND THUNDERSTORMS AT TIMES THROUGH THE PERIOD. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHOWERS AND THUNDERSTORMS HAVE INCREASED IN COVERAGE ACROSS INDIANA AND WILL PUSH EAST SOUTHEAST ACROSS THE FORECAST AREA THROUGH THE MORNING AND EARLY AFTERNOON. HIGH RESOLUTION MODELS SEEM TO HAVE A GOOD HANDLE ON THIS...SO THERE IS MODERATE CONFIDENCE THAT THIS ACTIVITY WILL PUSH OFF EAST OF THE REGION BY MID AFTERNOON LEAVING A DRY PERIOD FOR THE END OF THE DAY. WITH WIDESPREAD ACTIVITY AND LIMITED HEATING...EXPECT SEVERE THREAT TO BE LIMITED AT BEST. WILL BE SOME HEAVY DOWNPOURS. ALTHOUGH STORMS ARE PROGRESSIVE THE ALIGNMENT OF THE STORMS COULD ALLOW FOR SOME TRAINING PARTICULARLY ACROSS THE NORTHERN COUNTIES. TEMPERATURES WILL BE SLOW TO RISE WITH THE PRECIPITATION IN THE AREA. ONCE THIS MOVES OFF THERE SHOULD AT LEAST BE BREAKS IN THE CLOUDS AND TEMPERATURES WILL BE ABLE TO WARM. STILL SEEMS THAT MID TO UPPER 80S ARE POSSIBLE IN SOUTHERN COUNTIES. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... NEXT DISTURBANCE IN THE NORTHWEST FLOW ALOFT WILL AFFECT THE AREA TONIGHT. THERE ARE INDICATIONS A LARGE COMPLEX OF STORMS/MCS WILL FORM OVER MINNESOTA AND WISCONSIN AND DIVE SOUTHEASTWARD. SOME TIMING AND PLACEMENT DISCREPANCIES EXIST...BUT THE MOST LIKELY TRAJECTORY APPEARS TO BE TOWARD THE NORTHERN HALF OF THE CWA...SO HAVE ALIGNED POPS ACCORDINGLY. IF AN ORGANIZED MCS DEVELOPS...THERE MAY BE AN ATTENDANT RISK FOR STRONG TO DAMAGING WINDS. HOWEVER THE DIURNALLY UNFAVORABLE TIMING MAY LEAD TO A WEAKENING TREND. SPC HAS PLACED THE WESTERN HALF OF THE CWA IN A SLIGHT RISK. ALSO...WPC HAS PLACED THE AREA IN A SLIGHT RISK OF EXCESSIVE RAINFALL DUE TO THE MULTIPLE CLUSTERS OF THUNDERSTORMS WITH HEAVY RAIN. WITH A MOIST AIRMASS AND CLOUD COVER...LOWS WILL ONLY DROP INTO THE LOWER 70S IN MANY SPOTS. MORE STORMS WILL BE POSSIBLE ON FRIDAY...BUT COVERAGE IS IN QUESTION AS CONFIDENCE DECREASES ON INDIVIDUAL FEATURES IN THE NORTHWEST FLOW. HOWEVER...HIGH PRECIPITABLE WATER VALUES AND THE LINGERING BOUNDARY ACROSS THE REGION WILL ACT IN FAVOR OF THUNDERSTORM DEVELOPMENT DURING PEAK HEATING. A SIMILAR SCENARIO APPLIES TO SATURDAY. COMPLICATING MATTERS IS A SLIGHT CHANGE IN THE PATTERN ORIENTATION FROM SATURDAY INTO SUNDAY. THE CENTRAL CONUS RIDGE IS EXPECTED TO CONTINUE TO BUILD...AS A TROUGH DIGS OVER THE WESTERN ATLANTIC. THERE ARE NOW INDICATIONS THAT HIGH PRESSURE OVER THE ST. LAWRENCE VALLEY WILL NOSE SOUTHWESTWARD...SERVING TO BACK DOOR FRONT THE LOW LEVEL BOUNDARY. THIS MAY SHIFT THE FOCUS OF ANY STORMS THAT DEVELOP. BY SUNDAY THE LOW LEVEL BAROCLINIC ZONE BECOMES MORE DIFFUSE...LOW LEVEL FLOW WEAKENS...AND ATMOSPHERIC MOISTURE LESSENS...SO STORM CHANCES MAY BE PRETTY LOW. FRIDAY AND SATURDAY WILL LIKELY BE THE WARMEST DAYS OF THE SHORT TERM PERIOD WITH HIGHS IN THE UPPER 80S TO LOWER 90S. HEAT INDICES IN THE SOUTHWEST WILL BE NEAR 100. BY SUNDAY...THE NORTHEAST SURFACE FLOW MAY HELP LIMIT TEMPERATURES A BIT. WITH HIGH DEW POINTS...OVERNIGHT LOWS WILL CONTINUE TO RESIDE ON EITHER SIDE OF 70. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... GETTING INTO MONDAY-TUESDAY...THE RIDGE CONTINUES TO BUILD WITH HEAT/HUMIDITY. FLOW BECOMES VERY LIGHT THROUGH THE BULK OF THE TROPOSPHERE AND IT BECOMES QUESTIONABLE IF COVERAGE OF DAYTIME/EVE STORMS WARRANTS MENTION. RIGHT NOW HAVE RUN 15-25% RAIN CHANCES BOTH OF THESE DAYS...AND THAT MAY BE TOO HIGH. INTO WEDNESDAY...SOME HINTS OF HEIGHT FALLS WHICH MAY ALLOW A LITTLE STRONGER FLOW OR A WEAK SHORTWAVE TROUGH TO CROSS THE GREAT LAKES. SO A BETTER STORM THREAT THEN...HOWEVER AT THIS TIME RANGE THIS IS A VERY LOW CONFIDENCE FORECAST GIVEN CONDITIONAL NATURE OF THE RIDGE BUCKLING. SO ALL IN ALL...HAVE TENDED TO FOCUS RAIN CHANCES NEAR PEAK HEATING INTO THE EVENING AND ALLOW FOR SOME DRY NIGHTS/EARLY MORNINGS. FLY IN OINTMENT WILL BE ANY FORWARD PROPAGATING MCS THAT SURVIVES THROUGH THE NIGHT...ORIGINATING TO OUR NORTHWEST AND FALLING DOWN NNWLY FLOW EITHER SATURDAY MORNING OR SUNDAY MORNING. LOW CONFIDENCE STORM CHANCE...BUT HIGH CONFIDENCE WARM/HUMID PATTERN IS THE STORY FOR THE SAT-WED TIMEFRAME. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... THE REGION WILL BE WEDGED BETWEEN TWO SYNOPTIC SCALE SYSTEMS OVER THE NEXT 24 HOURS. A MID LEVEL CLOSED LOW SLOWLY MOVING FROM THE EASTERN GREAT LAKES TO THE NEW ENGLAND AREA. MEANWHILE...A MID LEVEL RIDGE WILL TRY TO NUDGE A BIT NORTHWARD INTO THE MIDDLE MISSISSIPPI VALLEY. OUR AREA WILL BE INFLUENCED BY THE NORTHWEST FLOW ALOFT BETWEEN THESE TWO SYSTEMS ALONG WITH EMBEDDED DISTURBANCES RIDING SOUTHEAST ON THE EAST SIDE OF THE RIDGE AXIS FROM TIME TO TIME. THERE IS SOME CONSENSUS IN THE POTENTIAL FOR CONVECTION IN THE NEXT 12 HOURS. A WEAK DISTURBANCE WILL MOVE SOUTHEAST ACROSS NRN OHIO LATE THIS MORNING/EARLY AFTERNOON. ALSO...A LOW LEVEL JET WILL IMPINGE ON THE REGION FROM THE WEST. WE CONTINUE TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS THIS MORNING PER MOSAIC RADAR...AND THIS CONVECTION SHOULD MOVE EAST/SOUTHEAST THROUGH THE 12Z-20Z TIME FRAME. MVFR CONDITIONS ARE LIKELY WITH STORMS WITH SOME LOCAL IFR VSBYS POSSIBLE IN THE HEAVIER SHOWERS/STORMS. FOR LATER THIS AFTERNOON...MODELS INDICATE WE COULD BE IN A RELATIVE LULL AS THE LOW LEVEL JET DIURNALLY WEAKENS AND THE DISTURBANCE MOVES AWAY. HAVE LEFT A VCSH DESCRIPTOR AT THE TAF SITES FOR LOW CHANCES FOR SHOWERS. FOR TONIGHT INTO FRIDAY MORNING...ANOTHER EMBEDDED DISTURBANCE IS FORECAST TO ROTATE SOUTHEAST INTO THE REGION. THERE CONTINUES TO BE DIFFERENCES IN THE EVOLUTION OF NOCTURNAL CONVECTION. RIGHT NOW...THE BEST CHANCE FOR SHOWERS/STORMS SHOULD OCCUR AFTER 06Z AND BE MORE WEIGHTED TOWARDS THE NORTHERN TAF SITES OF KDAY...KCMH...AND KLCK. HOWEVER...IT SHOULD BE NOTED THAT SOME MODELS HAVE CONVECTION AFFECTING THE ENTIRE REGION IN THE FORM OF A MESOSCALE CONVECTIVE SYSTEM. WILL CONTINUE TO MONITOR MODEL TRENDS FOR TIMING AND SPATIAL COVERAGE. OUTLOOK...THUNDERSTORMS POSSIBLE FRIDAY EVENING THROUGH SUNDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...SNYDER NEAR TERM... SHORT TERM...SNYDER LONG TERM...BINAU AVIATION...HICKMAN

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.