Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 010545 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 145 AM EDT SUN MAY 1 2016 .SYNOPSIS... SHOWERS ASSOCIATED WITH A WARM FRONT AHEAD OF ILLINOIS LOW PRESSURE WILL BECOME LESS NUMEROUS OVERNIGHT AS THE FRONT LIFTS NORTH. SHOWERS AND THUNDERSTORMS WILL BE LIKELY SUNDAY AFTERNOON AND EVENING WHEN ANOTHER WAVE OF LOW PRESSURE IS FORECAST TO TRACK ACROSS OHIO. DRIER CONDITIONS ARE EXPECTED MONDAY WHEN HIGH PRESSURE WILL BE CENTERED OVER THE GREAT LAKES. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... WIDESPREAD PRECIPITATION ACROSS THE ILN FORECAST AREA IS CONTINUING TO MOVE NORTHEAST...BUT PRECIPITATION CHANCES (ESPECIALLY FOR THE SOUTHEASTERN HALF OF THE CWA) WILL REMAIN VERY HIGH THROUGH THE NEXT SEVERAL HOURS. NEW DEVELOPMENT OVER SOUTH-CENTRAL KENTUCKY IS FORECAST TO MOVE INTO NORTHEASTERN KENTUCKY OVER THE NEXT FEW HOURS...EVENTUALLY OVERSPREADING AT LEAST A PORTION OF THE ILN FORECAST AREA. THIS ACTIVITY SHOULD MOVE OUT BY EARLY MORNING...AND DRIER CONDITIONS ARE EXPECTED BY SUNRISE. HOWEVER...THE CHANCES FOR THUNDERSTORMS TONIGHT HAVE CONTINUED TO TREND DOWN. CURRENT OBSERVATIONS (LOOKING MAINLY AT T/TD) AND RAP ANALYZED THETA-E SUGGEST THAT THE SURFACE WARM FRONT HAS ONLY RECENTLY ENTERED THE FAR SOUTHWESTERN PORTION OF THE ILN FORECAST AREA. LAPS ANALYSIS OF SURFACE BASED CAPE SUGGESTS THAT ANY BOUNDARY LAYER INSTABILITY HAS STALLED ITS NORTHEASTWARD PROGRESSION...AND HRRR/RAP PROJECTIONS SUGGEST IT WILL NOT GET ANY CLOSER. THUS...ONLY SOME ELEVATED INSTABILITY WILL ALLOW FOR A FEW UPDRAFTS TO POSSIBLY GENERATE SOME LIGHTNING TONIGHT...AND PRIMARILY IN THE SOUTHERN THIRD OF THE CWA. TEMPERATURES ARE STILL ON TRACK FROM THE PREVIOUS FORECAST...AND ARE EXPECTED TO CHANGE VERY LITTLE THROUGH SUNDAY MORNING. PREVIOUS DISCUSSION > SURFACE ANALYSIS SHOWS A WARM FRONT EXTENDING ACROSS TENNESSEE FROM MISSOURI LOW PRESSURE. AS THE LOW MOVES TO ILLINOIS TONIGHT...THE FRONT IS FORECAST TO LIFT NORTH TO BE NEAR THE NORTHERN BORDER OF THE ILN FA. WIDESPREAD SHOWERS EVIDENT ON RADAR WILL GRADUALLY DIMINISH FROM THE SOUTH AS THE MAIN SWATH OF MOISTURE AND ISENTROPIC LIFT IS PUSHED NORTH AHEAD OF THE WARM FRONT. CONVECTION WILL BE SCATTERED IN NATURE FROM EVENING THROUGH THE OVERNIGHT HOURS...WITH A FEW THUNDERSTORMS POSSIBLE AS INSTABILITY INCREASES SOMEWHAT ALONG AND BEHIND THE WARM FRONT. LOW TEMPERATURES WILL VARY WITH RESPECT TO WARM FRONTAL LOCATION...WITH 6 AM READINGS RANGING FROM THE LOW 50S NORTH TO AROUND 60 SOUTH. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... A LULL IN CONVECTION IS EXPECTED EARLY SUNDAY WHEN THE WARM FRONT AND INITIAL WAVE OF LOW PRESSURE WILL BE NORTH OF THE AREA. THAT WILL CHANGE FOR SUNDAY AFTERNOON INTO SUNDAY NIGHT AS ANOTHER WAVE OF LOW PRESSURE DEVELOPS TO THE WEST IN RESPONSE TO A POTENT MID LEVEL SHORT WAVE. THE LOW IS FORECAST TO TRAVEL ROUGHLY ALONG I-70 THROUGH INDIANA AND OHIO SUNDAY AFTERNOON AND EVENING...CARRYING A RATHER IMPRESSIVE SWATH OF MOISTURE AND LIFT. WARM ADVECTION AHEAD OF THE LOW WILL HELP BOOST HIGH TEMPERATURES INTO THE MID 70S...WHICH WILL RESULT IN INCREASED LAPSE RATES AND INSTABILITY. CAPES AROUND 2000 J/KG WILL BE ATTAINED...AND SHOWERS AND THUNDERSTORMS WILL BE LIKELY. WITH MODEL SOUNDINGS INDICATING DELTA THETA E VALUES EXCEEDING 20 KELVIN...AND WITH A POTENT MID LEVEL JET AIDING STORM TOP DIVERGENCE...SOME OF THE THUNDERSTORMS COULD BECOME SEVERE WITH DAMAGING WINDS AND LARGE HAIL POSSIBLE. SHOWERS AND THUNDERSTORMS WILL DIMINISH SUNDAY NIGHT AS THE LOW MOVES TO PENNSYLVANIA. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... SPLIT FLOW PATTERN WITH AN INITIAL SFC WAVE PUSHING EAST EARLY MONDAY. SOUTHWEST FLOW ALOFT CONTINUES WITH MID LEVEL TROF LAGGING. ALL NUMERICAL MODEL SOLNS HOLD ONTO PCPN LONGER...SO HAVE KEPT CHANCE POPS ACRS THE SOUTH/SOUTHEAST THRU THE DAY MONDAY AND INTO MONDAY NIGHT. HIGHS ON MONDAY WILL BE A LITTLE BELOW NORMAL...RANGING FROM 60 NORTH TO 65 SOUTH. WEAK SFC HIGH PRESSURE WILL PROVIDE A TEMPORARY DRY PERIOD LATER MONDAY NIGHT AND TUESDAY. READINGS WILL BE CLOSER TO NORMAL TUESDAY...WITH HIGHS FROM THE MID 60S NORTH TO NEAR 70 SOUTH. NUMERICAL MODEL SOLNS GENERALLY SIMILAR WITH NRN STREAM TROF SHARPENING UP AND DIGGING SOUTH AT MID WEEK. THIS WILL ALLOW A SFC COLD FRONT TO DROP SOUTH THRU ILN/S FA WEDNESDAY. INSTABILITY IS MARGINAL AT BEST...SO AT THIS TIME HAVE ELECTED TO KEEP PCPN MENTION TO CHANCE OF SHOWERS. TEMPERATURES WILL CONTINUE TO REMAIN CLOSE TO NORMAL WITH HIGHS WED FROM THE MID 60S NORTH TO AROUND 70 SOUTH. DIGGING TROF DEVELOPS INTO DEEP LARGE CLOSED LOW WHICH WILL CONTINUE TO INFLUENCE OUR WEATHER THRU AT LEAST THE END OF THE WEEK. THIS FEATURE WILL KEEP CHANCE POPS FOR SHOWERS IN THE FCST THURSDAY AND FRIDAY. MAY HAVE TO INCLUDE A MENTION OF SHOWERS IN THE EAST ON SATURDAY WITH THE SOME EVIDENCE THAT MOISTURE WILL CONTINUE TO WRAP AROUND THIS LARGE LOW. FOR NOW HAVE OPTED FOR DRY SOLN SATURDAY. TEMP WISE...UNDER THE INFLUENCE OF THIS LOW...BOTH THURSDAY AND FRIDAY WILL BE BELOW NORMAL WITH HIGHS FROM THE UPPER 50S NORTH TO THE MID 60S SOUTH. READINGS WILL ONLY MODERATE A LTL SATURDAY WITH HIGHS FROM THE LOWER 60S NORTH THE UPPER 60S SOUTH. && .AVIATION /05Z SUNDAY THROUGH THURSDAY/... MOSTLY IFR CIGS ACROSS THE TERMINALS THIS MORNING WITH KDAY EVEN LIFR. SOME SITES HAVE BROKEN TO VFR BUT THIS SHOULD BE TRANSIENT AS LOW LEVEL MOISTURE REMAINS WIDESPREAD. GFS/ NAM FORECAST SOUNDINGS ALSO SUPPORT THIS. WIDESPREAD PRECIP HAS ALSO STARTED TO TAPER OFF A BIT THIS MORNING AS AN UPPER LEVEL DISTURBANCE BEGINS TO PULL NORTH OF THE AREA. THIS WEAK AREA OF SUBSIDENCE BEHIND THE DISTURBANCE WOULD SUPPORT A BRIEF BREAK IN PRECIP EARLY THIS MORNING. IFR CIGS WILL THEN BEGIN TO SLOWLY LIFT LATE MORNING TURNING TO MVFR AND THEN FINALLY VFR BY THIS AFTERNOON. GFS/ NAM SOUNDINGS IN GENERAL SUPPORT THIS WITH COLUMBUS FORECASTED TO BREAK OUT FIRST. CONFIDENCE ON THE RETURN OF PRECIP IS LOW AS HIGH RES MODELS HAVE DONE A POOR JOB THUS FAR CAPTURING ON GOING PRECIP IN INDIANA/ ILLINOIS. SOME SLIGHTLY DRIER AIR MIGHT WORK INTO THE NORTHERN TAF SITES... WHICH COULD HELP LIMIT SOME PRECIP DEVELOPMENT... BUT THIS LOOKS UNLIKELY AS FRONT WILL REMAIN STALLED NORTH OF THE AREA. HAVE TRENDED TAFS TO AN EARLIER REDEVELOPMENT AS FORECAST SOUNDINGS INDICATE A MOIST ATMOSPHERE WITH INSTABILITY DEVELOPING. LOW LEVEL SOUTHWEST FLOW PRESENT WOULD SUPPORT UPPER LEVEL DISTURBANCES MOVING OVERHEAD. THE BEST CHANCE OF PRECIP LOOKS TO BE AROUND 20Z AS A SHORTWAVE MOVES INTO THE AREA. THE GFS/ NAM/ RAP ALL HAVE SLIGHTLY DIFFERENT TIMING THOUGH. FORECAST SOUNDINGS ALSO SUPPORT THUNDER THIS AFTERNOON. DUE TO UNCERTAINTY HAVE KEPT THUNDER OUT OF TAFS FOR NOW. OUTLOOK...MVFR CEILINGS ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...CONIGLIO NEAR TERM...CONIGLIO/HATZOS SHORT TERM...CONIGLIO LONG TERM...AR AVIATION...HAINES

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