Area Forecast Discussion
Issued by NWS Wilmington, OH

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000
FXUS61 KILN 190542
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
142 AM EDT SUN APR 19 2015

.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL BEGIN TO PULL EAST AND WASHOUT
AS AN UPPER LEVEL LOW OVER THE ROCKIES MOVES EAST. A WARM FRONT
WILL THEN LIFT ACROSS THE REGION SUNDAY AFTERNOON FOLLOWED BY A
COLD FRONT MONDAY EVENING.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MID LEVEL RIDGE TO SHIFT EAST OF THE REGION BY MORNING WITH THE
FLOW BACKING SRLY AHEAD OF EMBEDDED S/W. FAVORABLE ISENTROPIC
LIFT DEVELOPS AHEAD OF THIS S/W BY SUNRISE. BASED ON LATEST TRENDS
FROM BOTH SYNOPTIC MODELS AND MESOSCALE MODELS...HAVE SLOWED DOWN
PRECIPITATION SLIGHTLY WITH CHC POPS FOR SHOWERS INTO THE SW
TOWARD SUNRISE QUICKLY RAMPING UP TO CATEGORICAL SUNDAY MORNING.

PREVIOUS FCST IN GOOD SHAPE WITH LOWS RANGING FROM THE UPPER 40S
NE TO THE UPPER 50S SW.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/...
THE CHANCE OF RAIN SUNDAY WILL BEGIN TO QUICKLY INCREASE AS WAVES
OF PVA MOVE FROM THE GULF COAST UP AND AROUND THE BASE OF THE
UPPER LEVEL LOW TOWARDS OHIO. HIGH RES MODELS ARE SHOWING A BROAD
PRECIP SHIELD AHEAD OF THE WARM SECTOR ARRIVING INTO CINCINNATI
AROUND 8 AM AND THEN EXPANDING TO COLUMBUS AROUND 2 PM. PWATS ON
THE BOTH THE GFS AND NAM ARE FORECASTED TO REACH 1.65" BY SUNDAY
AROUND NOON (NEARING 99TH PERCENTILE FOR THIS TIME OF YEAR). CAPE
VALUES SUNDAY WILL BE VERY LOW BUT 0 - 3 KM SRH VALUES ON BOTH THE
GFS AND NAM SOUNDINGS ARE VERY IMPRESSIVE. SRH VALUES ARE IN THE
400 TO 600 M2 /S2 RANGE SUNDAY AFTERNOON AS A SURFACE LOW
APPROACHES FROM THE SOUTHWEST. AS OF NOW EXPECTING PRECIP SHIELD
TO BE MOSTLY WAA DRIVEN INITIALLY WITH STORMS NOT BEING ABLE TO
FULLY UTILIZE SUCH HIGH LOW LEVEL SRH VALUES.

A WARM FRONT WILL THEN MOVE THROUGH THE AREA SUNDAY AFTERNOON
WHICH WILL ALLOW FOR A BRIEF BREAK IN THE PRECIP BEFORE THE
REMNANTS OF THE UPPER LEVEL LOW SHEAR OUT AND MOVE OVER THE AREA
LATE SUNDAY/ EARLY MONDAY. SUNDAY AFTERNOON AND MONDAY AFTERNOON A
FEW THUNDERSTORMS WILL ALSO BE POSSIBLE AS CAPE VALUES COME UP A
BIT. THE INITIAL SHORTWAVE THAT DISLODGED THE LOW OVER THE
ROCKIES WILL BEGIN TO OCCLUDE AND PUSH A COLD FRONT THROUGH THE
AREA MONDAY EVENING. THE GFS AND NAM ARE IN PRETTY GOOD AGREEMENT
WITH THE TIMING OF THE FRONT FOR MONDAY EVENING WHILE THE EURO
PUSHES THE FRONT THROUGH SLIGHTLY QUICKER. GIVEN THE OCCLUSION
PROCESS OF THE LOW ONGOING AT THE TIME HAVE LEANED TOWARDS THE
SLOWER FRONTAL PASSAGE. RAIN CHANCES WILL THEN LESSEN TUESDAY AS
DRIER AIR MOVES IN FROM THE WEST.

IT WILL ALSO BE BREEZY THE NEXT COUPLE OF DAYS AS 850 MB WINDS
ARE FORECASTED TO BE CONSISTENTLY AROUND 40 KTS. THIS WILL BE
THANKS TO AN ELEVATED PRESSURE GRADIENT THOUGH THE SHORT TERM.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GOOD AGREEMENT BETWEEN MODELS CONTINUING TO EXHIBIT AN UPPER LOW
OVER SOUTHERN ONTARIO DOMINATING THE EARLY/MID EXTENDED PERIOD
KEEPING UNSEASONABLY COOL TEMPERATURES AND CONSIDERABLE CLOUDS IN
ESPECIALLY THE NORTHERN FCST AREA. THE BEST CHANCE FOR SHOWERS FOR
THE ENTIRE FORECAST AREA WILL COME WHEN THE SFC HIGH IN THE SE
UNITED STATES MOVES OFFSHORE AND ALLOWS FOR AN ELONGATED COLD FRONT
TO SLOWLY PASS THROUGH THE AREA ON WED AND LINGER JUST SOUTH OF THE
FCST AREA WED NIGHT. THE UPR LOW FINALLY BEGINS TO PUSH EAST ENOUGH
TO LOSE ITS INFLUENCE ON FCST AREA BY FRIDAY NIGHT INTO SATURDAY.
SOME MODEL DIFFERENCES THIS FAR OUT IN THE FORECAST IN THAT THE
ECMWF IS MORE AMPLIFIED WITH A SOUTHERN STREAM SHORTWAVE...BRINGING
IT INTO THE TN AND LOWER OHIO VALLEYS...WHEREAS THE GFS KEEPS IT
FURTHER SOUTH OVER THE GULF COAST STATES WHILE CONTINUING TO AMPLIFY
THE DEPARTING UPR LOW. HAVE COMPROMISED WITH CHANCE OF PRECIP IN
ESPECIALLY THE SOUTHERN THIRD OF FCST AREA.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
ACTIVE WEATHER IS EXPECTED THROUGH THE TAF PERIOD...ALTHOUGH VFR
CONDITIONS ARE EXPECTED FOR THE FIRST 6-12 HOURS. AN AREA OF
RAIN IS EXPECTED TO DEVELOP AND MOVE NORTH INTO THE TAF SITES
BETWEEN 11Z AND 15Z...THOUGH CONDITIONS MAY INITIALLY BE VFR AS
THE RAIN BEGINS. HOWEVER...LOW-LEVEL MOISTURE WILL THICKEN OVER
TIME...LEADING TO MVFR CEILINGS AND VISIBILITIES. DURING THE
AFTERNOON...THERE IS A CHANCE THAT SOME IFR CEILINGS MAY
DEVELOP...AND HEAVIER RAIN SHOWERS COULD ALSO PRODUCE BRIEF IFR
VISIBILITIES. ALTHOUGH RAIN WILL BECOME A LITTLE MORE SCATTERED BY
LATE AFTERNOON...THERE DOES APPEAR TO BE A SLIGHT CHANCE OF
THUNDER...THOUGH NOT YET CLEAR ENOUGH IN TIMING OR PLACEMENT TO
INCLUDE IN THE TAFS. RAIN WILL BECOME MUCH MORE SCATTERED GOING
INTO THE OVERNIGHT HOURS...BUT WITH ENOUGH SHOWERS AROUND TO KEEP
A VCSH IN THE TAFS. CEILINGS MAY IMPROVE SLIGHTLY GOING INTO THE
NIGHT...BUT THIS IS ALSO NOT TOTALLY CERTAIN.

THE OTHER ISSUE TO HANDLE IS THE WINDS...WHICH WILL INCREASE IN
STRENGTH DURING THE MORNING HOURS. BY AFTERNOON...SUSTAINED WINDS
WILL BE AS HIGH AS 20 KNOTS...WITH GUSTS THAT MAY APPROACH 30
KNOTS AT TIMES. WINDS WILL SUBSIDE SLIGHTLY DURING THE LATE
EVENING AND INTO THE OVERNIGHT HOURS. IN TERMS OF
DIRECTION...WINDS SHOULD MAKE A GRADUAL CLOCKWISE TURN THROUGH THE
TAF PERIOD...BEGINNING WITH AN ENE DIRECTION AND ENDING FROM THE SSW.

OUTLOOK...MVFR/IFR CEILINGS AND VISIBILITIES ARE POSSIBLE MONDAY...WITH
A CHANCE OF THUNDERSTORMS.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.

&&

$$
SYNOPSIS...HAINES
NEAR TERM...AR
SHORT TERM...HAINES
LONG TERM...JDR
AVIATION...HATZOS





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