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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