Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 200735
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
335 AM EDT WED AUG 20 2014

.UPDATE...
ISSUED AT 235 AM EDT WED AUG 20 2014

STORMS HAVE EXPANDED ALONG SOME FORCING ASSOCIATED WITH A PASSING
SHORT WAVE TROUGH. THE MORE WIDESPREAD ACTIVITY IS OCCURRING CLOSER
TO THE OHIO RIVER. OUR BLUEGRASS COUNTIES WILL STAND THE BEST CHANCE
OF SEEING MORE CONCENTRATED CONVECTION BETWEEN 2:30 AND 4 AM...WITH
MORE SCATTERED ACTIVITY GRADUALLY WORKING FROM WEST TO EAST THROUGH
DAWN. UPDATES HAVE BEEN SENT.

UPDATE ISSUED AT 1101 PM EDT TUE AUG 19 2014

UPDATED THE FORECAST TO BETTER TIME THE APPROACHING BAND OF SHOWERS
AND THUNDERSTORMS OVER CENTRAL KENTUCKY. THE REST OF THE FORECAST IS
ON TRACK.

UPDATE ISSUED AT 804 PM EDT TUE AUG 19 2014

UPDATED THE FORECAST TO END THE PRECIPITATION FOR THE LATE AFTERNOON
AND THEN TO TIME IN THE NEXT BATCH OF SHOWERS AND THUNDERSTORMS INTO
THE AREA DURING THE OVERNIGHT. HAVE VERY LOW CONFIDENCE IN THE MODELS
DUE TO THE BIG DIFFERENCES IN TIMING. WENT WITH A MIX OF THE HRRR
...EXTRAPOLATION AND A MODEL CONSENSUS TO TRY AND TIME A BAND OF
SHOWERS AND THUNDERSTORMS INTO THE AREA TONIGHT ASSOCIATED WITH A
SHORT WAVE WHICH WILL BE MOVING INTO THE AREA FROM THE WEST TONIGHT.
THE 0 TO 6 KM MEAN FLOW IS ONLY AROUND 12 MPH AND THE PRECIPITABLE
WATER IS AROUND 1.6 INCHES TONIGHT...SO WILL NEED TO KEEP AN EYE ON
THE PRECIPITATION AMOUNTS FOR POTENTIAL HYDRO ISSUES. THE
INSTABILITY IS CLEARLY SUFFICIENT FOR ANY CONVECTION TO RESULT IN
THUNDER. FEEL PRETTY CONFIDENT THAT THERE WILL BE A LINE MOVING
THROUGH THE AREA TONIGHT...HOWEVER DO NOT HAVE GOOD CONFIDENCE IN THE
TIMING.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 258 PM EDT TUE AUG 19 2014

ISOLATED DIURNALLY DRIVEN CONVECTION OVER THE SOUTHEAST PART OF THE
FORECAST AREA CONTINUES TO WANE. EXPECT A CONTINUED DECREASING TREND
THROUGH THE REMAINDER OF THE DAY AND WILL CARRY ONLY ISOLATED
SHOWERS...NO THUNDER...FOR THE EVENING PORTION OF THE FORECAST.

OVER THE NEXT 36 HOURS SHORT WAVES WILL CONTINUE TO ROTATE AROUND THE
PARENT UPPER LOW WHICH IS SITUATED OVER THE GREAT LAKES. THIS KEEPS A
NEARLY CONSTANT THREAT OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. THE
FIRST WAVE WILL AFFECT THE AREA TONIGHT...AND A SECOND WAVE LOOKS TO
IMPACT THE AREA WEDNESDAY NIGHT. AT THE SURFACE A WEAK COLD FRONT IS
ADVANCING ESE ACROSS IL. SHOWERS AND THUNDERSTORMS OUT AHEAD OF THIS
FEATURE WILL CONTINUE TO MOVE TOWARDS EAST KY THROUGH THE REST OF THE
AFTERNOON AND EVENING. THERE IS CONSIDERABLE UNCERTAINTY HOW LONG THE
SHOWERS AND THUNDERSTORMS WILL MAINTAIN THEMSELVES AFTER SUNSET AS
THE BEST FORCING LOOKS TO REMAIN NORTH OF OUR AREA TONIGHT...AND
MODEL DATA SUPPORTS A WEAKENING TREND WITH ANY CONVECTION THAT MOVES
INTO OUR AREA LATER TONIGHT. EVEN SO WILL STILL NEED TO CARRY SHOWER
AND THUNDERSTORM CHANCES LATER TONIGHT...WITH THE BEST CHANCES IN THE
NORTHWEST AND LOWEST CHANCES IN THE SOUTHEAST.

ON WEDNESDAY THE FRONT WILL STALL IN OUR VICINITY...AND MORE
CONVECTION WILL BE POSSIBLE ESPECIALLY IN THE AFTERNOON. AS ANOTHER
WAVE APPROACHES WEDNESDAY NIGHT AND THE FRONT BEGINS LIFTING
NORTHEAST SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE. THE MUGGY
WEATHER WILL PERSIST AS THERE WILL BE LITTLE CHANGE IN DAILY
TEMPERATURE TRENDS AND DEWPOINTS WILL CONTINUE TO RUN IN THE UPPER
60S TO LOWER 70S.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 AM EDT WED AUG 20 2014

THE EXTENDED PORTION OF THE FORECAST BEGINS ON THURSDAY NIGHT WITH A
SLOWLY BUILDING RIDGE OVER THE CENTRAL CONUS AND DIGGING TROUGHS
OVER THE NORTHWEST AND NORTHEAST. THIS GENERAL TREND CONTINUES
THROUGH THE ENTIRE EXTENDED PERIOD. DURING THIS PERIOD...QUITE A FEW
STRONG SHORTWAVES TRAVEL OVER THE BUILDING RIDGE IN THE CENTRAL
PLAINS AND INTO THE OH VALLEY AND GREAT LAKES REGION. THE FIRST WAVE
OF NOTE WILL BE THE SHORTWAVE MOVING THROUGH AT THE BEGINNING OF THE
EXTENDED. AFTER THIS...THE PATTERN TURNS INTO A MORE MCS DRIVEN
PATTERN FRIDAY THROUGH SUNDAY WITH ACTIVITY CENTERED AROUND WHAT THE
DAYS CONVECTION BRINGS AND IS DIURNALLY AFFECTED. THROUGH THE PERIOD
THE UPPER RIDGE SLOWLY WEAKENS AND DRIFTS EAST.

CONCERNING THE MODELS DURING THE EXTENDED...THE GFS AND EURO LOOK TO
BE RIGHT ON TRACK AND IN GOOD AGREEMENT. THOUGH...THE EURO LOOKS TO
CUT OFF ANY CONVECTION BY THE END OF THE EXTENDED AS THE RIDGE AXIS
SETS UP RIGHT OVER EASTERN KENTUCKY LEADING TO AN END TO ALL
DIURNALLY DRIVEN CONVECTION AND DISPLACING THE TRACK OF THE MCS MORE
TO THE NORTHEAST. BASED ON THE GOOD AGREEMENT...IT SEEMS TO BE A
GOOD CONSENSUS TO STAY CLOSE TO THE SOLUTION OF THE ALL BLEND MODEL.
THOUGH DEPENDING ON WHAT THE 00Z EURO DOES ON THE MONDAY AND TUESDAY
TIME FRAME FOR THE RIDGE AXIS RIGHT OVER THE AREA...MAY DROP POPS
BELOW THE ALL MODEL BLEND SOLUTION. WITH THE SOLUTION OF THE ALL
MODEL BLEND...THE BEST CHANCE OF POPS WILL BE DURING THE FRIDAY
THROUGH SUNDAY TIME FRAME AND LESS DURING THE MONDAY AND TUESDAY
TIME FRAME WHERE THE RIDGE WILL BE OVER EASTERN KENTUCKY AND HAVE
LEFT SLIGHT CHANCE MAINLY DURING THE AFTERNOON ON MONDAY AND
TUESDAY.

IN ADDITION TO THIS PATTERN...TEMPERATURES WILL BE ON THE INCREASE
IN EARNEST AS SOME OF THE WARMEST WEATHER OF THE ENTIRE SUMMER WILL
BEGIN TO SET IN FROM FRIDAY THROUGH THE REST OF THE EXTENDED. HIGH
TEMPERATURES WILL SURPASS 90 DEGREES IN SOME AREAS OF EASTERN
KENTUCKY AND HUMIDITY WILL BE ON THE INCREASE AS WELL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 235 AM EDT WED AUG 20 2014

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL WORK THEIR WAY
FROM WEST TO EAST ACROSS EASTERN KENTUCKY THROUGH DAWN. AREAS ALONG
AND NORTH OF THE I-64 CORRIDOR WILL SEE THE BEST CHANCE OF THE MORE
CONCENTRATED CONVECTION. AS SUCH...HAVE HANDLED MOST OF THIS ACTIVITY
WITH VCTS/VCSH AS SOME OF THIS ACTIVITY WILL LIKELY WEAKEN AS IT
HEADS EAST. EXPECT MVFR/IFR FOG TO SET IN BETWEEN 08 AND 12Z AS
WELL...WITH THE DEEPER RIVER VALLEYS ALONG WITH ANY LOCATIONS THAT
SEE MORE SUSTAINED RAINFALL SEEING IFR OR WORSE FOG. THERE SHOULD BE
A CONVECTIVE LULL IN THE MORNING...BEFORE SOME ISOLATED STORMS MAY
THREATEN AGAIN IN THE AFTERNOON.


&&

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

$$

UPDATE...GEOGERIAN
SHORT TERM...SBH
LONG TERM...SHALLENBERGER
AVIATION...GEOGERIAN





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