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000
FXUS63 KJKL 181643
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1243 PM EDT TUE JUN 18 2013

.UPDATE...
ISSUED AT 1243 PM EDT TUE JUN 18 2013

MADE ANOTHER UPDATE TO THE FORECAST. RAIN SHOWER ACTIVITY HAS
DECREASED ACROSS THE ENTIRE AREA MUCH MORE QUICKLY THAN PREVIOUSLY
ANTICIPATED. BASED ON OBSERVED RADAR AND SATELLITE TRENDS OVER THE
PAST FEW HOURS...IT HAS BECOME APPARENT THAT VERY FEW SHOWERS OR
STORMS ARE GOING TO FORM UPSTREAM FROM THE FORECAST AREA THE REST OF
THE DAY. THEREFORE...GREATLY DECREASED THE PRECIPITATION CHANCES FOR
THE REST OF TODAY AND TONIGHT. OVERALL ONLY EXPECTING ISOLATED TO
SCATTERED RAIN SHOWERS FOR THE MAJORITY OF THE AREA THROUGH 12Z
TOMORROW. MORE WIDESPREAD SHOWERS WILL CONTINUE TO MOVE ACROSS THE
COUNTIES BORDERING VIRGINIA AND WEST VIRGINIA THROUGH LATE THIS
AFTERNOON...BUT THINGS WILL WIND DOWN THERE AS WELL BY 0 TO 2Z THIS
EVENING. WIDESPREAD CLOUD COVER AND GREATLY RAIN COOLED AIR WILL
REDUCE INSTABILITY TO THE POINT THAT FURTHER STORM ACTIVITY IS NOT
ANTICIPATED TODAY OR TONIGHT. ALSO DECIDED TO DECREASE TODAYS HIGHS
BY A COUPLE OF DEGREES DUE TO THE INFLUENCE OF CLOUD COVER AND RAIN
AND PER TRENDS IN HOURLY OBS OVER THE FEW HOURS.

UPDATE ISSUED AT 1049 AM EDT TUE JUN 18 2013

MADE SOME UPDATES TO BOTH THE FORECAST GRIDS AND THE FORECAST TEXT
PRODUCT. BASED ON THE LATEST TRENDS IN RADAR DATA...AND WITH SUPPORT
FROM THE SREF AND NAM12 MODELS...DECIDED TO DECREASE PRECIPITATION
PROBABILITIES FOR THE REMAINDER OF THE DAY. THERE IS STILL SOME
UNCERTAINTY AS TO HOW QUICKLY ONGOING PRECIPITATION WILL DISSIPATE
THROUGHOUT THE DAY...BUT IT APPEARS THAT RAIN WILL REMAIN FAIRLY
WIDESPREAD THROUGH EARLY THIS AFTERNOON. ALSO RECALCULATED
PRECIPITATION AMOUNTS THROUGH 18Z TODAY...BASED ON THE LATEST DOWN
TREND IN PRECIPITATION INTENSITY AND AREAL COVERAGE. ALSO DECREASED
THE LIKELIHOOD OF THUNDERSTORM ACTIVITY AND HEAVY FOR THE REST OF THE
DAY...AS PRECIPITATION COOLED AIR AND WIDESPREAD CLOUD COVER WILL
KEEP INSTABILITY AT A BARE MINIMUM THROUGHOUT THE DAY. REMOVED
OUTDATED MORNING AND AFTERNOON WORDING FROM THE ZONE TEXT PRODUCT AS
WELL. THE UPDATE ZONES HAVE ALREADY BEEN SENT.

UPDATE ISSUED AT 828 AM EDT TUE JUN 18 2013

FORECAST WAS LARGELY ON TRACK. ONLY UPDATED TO BLEND OBSERVED
CONDITIONS INTO THE MORNING FORECAST.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 415 AM EDT TUE JUN 18 2013

LIGHT TO MODERATE RAIN WAS OCCURRING OVER MUCH OF THE AREA DURING THE
PREDAWN HOURS. THIS FOLLOWED AN EVENING WITH LOCALLY HEAVY RAINFALL
AND ISOLATED FLASH FLOODING. WILL EXPECT PRECIP TO CONTINUE INTO THE
DAY...WITH A POSSIBILITY OF THUNDER AS WELL. HOWEVER...LIMITED
INSOLATION WILL PREVENT SUBSTANTIAL DESTABILIZATION. THE BIGGEST
CONCERN WILL BE HEAVY RAINFALL DUE TO WEAK FLOW AND A VERY MOIST
ATMOSPHERIC COLUMN. HOWEVER...WITH LIMITED DESTABILIZATION...THERE IS
NOT A LOT OF CONFIDENCE IN GETTING EXTREME RAINFALL RATES SUCH AS
LAST EVENING. WE MAY END UP WITH SUBSTANTIAL RAINFALL...BUT OCCURRING
OVER A LONGER TIME FRAME. THE GFS WAS THE HEAVIEST ON PRECIP...BUT IT
WAS NOT VERIFYING WELL UPSTREAM IN NW TN AND SOUTH CENTRAL KY...WITH
AREAL AVERAGE RAINFALL SO FAR BEING LESS THAN THE GFS SUGGESTED. THIS
BEING THE CASE...HAVE OPTED NOT TO GO WITH A FLASH FLOOD WATCH AT
THIS POINT. HOWEVER...IT WILL NEED TO CONTINUE TO BE EVALUATED AS THE
EVENT EVOLVES THIS MORNING.

THE SHORTWAVE TROUGH...RIGHT ENTRANCE REGION OF UPPER JET...AND
SURFACE LOW COMBINING TO BRING PRECIP WILL BE MOVING OUT DURING THE
DAY...AND BY EARLY EVENING MOST OF THE PRECIP SHOULD HAVE ENDED.
HOWEVER...ANOTHER SHORTWAVE TROUGH WILL BE DROPPING IN FROM THE NW
TONIGHT. IT WILL NOT HAVE AS MUCH MOISTURE TO WORK WITH...BUT THE
MODELS DO SHOW SOME PRECIP ASSOCIATED WITH IT...AND 20-40 PERCENT
POPS WILL BE USED LOCALLY.

THIS WAVE WILL BE EXITING TO THE EAST WEDNESDAY MORNING. MODELS SHOW
SOME LIGHT PRECIP LINGERING INTO WEDNESDAY...BUT FORECAST SOUNDINGS
DO NOT LOOK VERY SUPPORTIVE. THINK THAT COVERAGE WOULD BE LOW...AND
HAVE OPTED FOR SUB-20 POPS AT THIS POINT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 415 AM EDT TUE JUN 18 2013

STATIONARY 500MB CUT OFF LOW OFF NW COAST TODAY WILL FINALLY BEGIN
TO ROTATE EASTWARD AND INLAND ACROSS WA AND OR BY START OF EXTENDED
FORECAST PERIOD. AS IT MOVES INLAND...ZONAL PATTERN ACROSS MUCH OF
THE CONUS WILL TRANSITION TO MORE MERIDIONAL...WITH STRONG RIDGING
FORMING OVER THE EXTREME SOUTH-CENTRAL CONUS. THIS PATTERN WILL
REMAIN IN PLACE THROUGH MUCH OF THE EXTENDED PERIOD...WITH LOW
STAYING STATIONARY OFF THE NW COAST THROUGH THE WORK WEEK. FOR
KY...WE WILL BE IN A SLIGHT TROUGHING PATTERN...WITH MULTIPLE
SHORTWAVES AND SURFACE BOUNDARIES EXPECTED TO DEVELOP OFF OF THE
MAIN 500MB LOW AND MIGRATE THROUGH THE TROUGH.
UNFORTUNATELY...MODELS ARE STILL HAVING QUITE A BIT OF DISAGREEMENT
ON TIMING AND IMPACTS OF THESE SHORTWAVES ACROSS EASTERN KY. 500MB
TROUGH OVER THE NW WILL FINALLY START TO MOVE EASTWARD AGAIN
SATURDAY. THOUGH MODELS ARE VERY DIVERGENT ON SOLUTIONS AT THIS
POINT...GENERAL CONSENSUS IS THAT THIS WILL PUSH A RIDGING PATTERN
FROM THE SOUTH-CENTRAL CONUS EASTWARD AND ACROSS THE MISSISSIPPI AND
OHIO VALLEYS. RIDGING WILL PERSIST THROUGH THE REST OF THE FORECAST
PERIOD /THROUGH THE WEEKEND AND BEGINNING OF NEXT WEEK/. THAT BEING
SAID...THIS WILL NOT STOP THE POTENTIAL FOR SOME AFTERNOON
CONVECTION OVER THE CWA...BUT BEING SO FAR OUT IN THE
FORECAST...WENT WITH A MODEL CONSENSUS FOR POPS AND QPF.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 828 AM EDT TUE JUN 18 2013

A MIX OF MOSTLY IFR AND MVFR COVERED THE AREA AT TAF ISSUANCE. LIGHT
TO MODERATE RAIN WAS WIDESPREAD. A THUNDERSTORM CAN NOT BE RULED OUT
AS TEMPS WARM UP. HOWEVER...THE RAIN WILL TAPER OFF FROM NW TO SE
DURING THE DAY...AND VFR WILL RETURN AS THAT HAPPENS. A COLD FRONT
AND ANOTHER UPPER LEVEL DISTURBANCE WILL BRING ANOTHER POSSIBILITY OF
SHOWERS AND THUNDERSTORMS TONIGHT. AS THE SYSTEM MOVES AWAY AND SKIES
CLEAR OUT TONIGHT...LIGHT WINDS AND LINGERING MOISTURE WILL PROBABLY
LEAD TO FOG AND LOW CLOUDS...WITH IFR IN MOST LOCATIONS OVERNIGHT.


&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...AR
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...HAL