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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KJKL 010726
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
326 AM EDT FRI AUG 1 2014

.SHORT TERM...
-- Changed Discussion --
(TODAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT FRI AUG 1 2014

THE MODELS START OUT IN GOOD AGREEMENT WITH AN UPPER LOW NEAR HUDSONS
BAY. THE KEY FEATURE IS A SHORT WAVE MOVING DOWN THE BACK SIDE OF THE
UPPER TROUGH. THIS SHORT WAVE IS FORECAST TO INTENSIFY AS IT DIPS
SOUTH INTO THE CENTRAL US. BY TONIGHT...THE SHORT WAVE WILL EXTEND
FROM LAKE SUPERIOR SOUTH ACROSS CENTRAL ILLINOIS INTO LOUISIANA. WITH
THIS SYNOPTIC PATTERN...THE COLD FRONT IS WELL THE SOUTH OF THE AREA
ALONG THE GULF COAST AND THE BLOCKING RIDGE OUT WEST IS BLOCKING ANY
FRONTS FROM MOVING INTO THE AREA. THE SHORT WAVE TROUGH AXIS IS FORECAST
TO MOVE ACROSS EASTERN KENTUCKY ON SATURDAY EVENING. THE MODELS ARE
IN GOOD AGREEMENT WITH THE TIMING OF THE TROUGH PASSAGE. THE MAIN
DRIVER OF THE WEATHER WILL BE THE GENERAL INSTABILITY ASSOCIATED WITH
THE UPPER LOW AND THEN THE PASSING OF THE UPPER TROUGH AXIS. THERE
HAS BEEN SOME MID LEVEL CAPPING THAT HAS HELD DOWN ANY CLOUDS FROM
GROWING BIG ENOUGH TO PRODUCE RAIN SHOWERS. AS THE TROUGH NEARS...THE
MID LEVEL CAPPING WILL BEGIN TO ERODE AND THE NET RESULT IS THAT SOME
ISOLATED TO SCATTERED THUNDERSTORMS AND SHOWERS WILL BE ABLE TO FORM.
THERE ARE ENOUGH DIFFERENCES IN HOW THE MODELS HANDLE THIS
SYSTEM...THAT CONFIDENCE IS LOWER THAN NORMAL WITH HOW WIDESPREAD
THE PRECIPITATION WILL BE. THERE COULD BE A SCENARIO WHERE THE ENERGY
WILL PASS TO THE NORTH AND SOUTH OF THE AREA AND THERE WILL BE
MINIMAL CONVECTION OF EASTERN KENTUCKY. THE PROBABILITY OF
PRECIPITATION IS A BIT LOWER THAN WHAT THE PREVIOUS FORECASTS HAD.

FOR TEMPERATURES USED A BLEND OF THE NAM AND GFS MOS AND THEN MADE
SOME ADJUSTMENTS FOR TERRAIN EFFECTS.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM EDT FRI AUG 1 2014

THE PERSISTENT TROUGH OVER THE EASTERN U.S. WILL DEAMPLIFY A BIT
THROUGH THE LONG TERM PERIOD BUT REMAIN PRETTY MUCH IN PLACE IN THE
MEANS. A PASSING SHORTWAVE WILL KEEP THE THREAT OF SHOWERS/STORMS IN
OUR FORECAST FOR SATURDAY NIGHT AND SUNDAY. WEAK HIGH PRESSURE WILL
THEN BUILD INTO THE REGION BY EARLY NEXT WEEK AND MOST LOCATIONS
SHOULD BE DRY AS A RESULT WITH THE EXCEPTION OF ALONG THE VIRGINIA
BORDER WHERE PROXIMITY TO DEEPER MOISTURE JUST TO OUR SOUTHEAST MAY
ALLOW A FEW SHOWERS/STORMS TO FIRE WITH DAYTIME HEATING MONDAY
AFTERNOON. A COLD FRONT WILL SAG SOUTHWARD SLOWLY THROUGH TIME INTO
THE OHIO VALLEY. MOST MODELS KEEP THIS FRONT WELL TO OUR NORTH
THROUGH MIDWEEK...BUT THE 01/00Z ECMWF SHIFTED COURSE AND IS AN
OUTLIER DROPPING IT ALL THE WAY THROUGH OUR AREA. WILL CONTINUE WITH
A DRY FORECAST FOR NOW THROUGH WEDNESDAY BEFORE RAIN CHANCES
INCREASE AGAIN ON THURSDAY AS THE FRONT APPROACHES. TEMPERATURES
WILL MODERATE SLOWLY THROUGH TIME BUT ONLY UP TO NORMAL LEVELS FOR
EARLY AUGUST BY WEDNESDAY AND THURSDAY.
-- End Changed Discussion --

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 156 AM EDT FRI AUG 1 2014

IN GENERAL EXPECTING VFR CONDITIONS THROUGH THE FORECAST PERIOD AT
THE TAF STATIONS...HOWEVER THERE WILL BE SOME VLIFR IN SOME OF THE
VALLEYS...ESPECIALLY NEAR RIVER AND STREAMS. THE ONLY TAF STATION
THAT IS IN DANGER OF IFR OR LOWER IS SME. THEY IS A ZERO SPREAD
BETWEEN TEMPERATURE AND DEWPOINT ALREADY...SO PRETTY MUCH WENT WITH A
PERSISTENCE FORECAST. AT THE OTHER TAF STATIONS...THE ONLY CONCERN IS
SOME STRATUS MOVING ACROSS THE TAF STATIONS AS THE FOG LIFTS OUT OF
THE VALLEY. LOOKING FOR SOME ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS MOVING ACROSS THE AREA FROM THE MID MORNING THROUGH THE
END OF THE TAF PERIOD. THE TIMING IS TOO UNCERTAIN TO PUT IN ANY
TEMPO GROUPS AT THIS TIME...HOWEVER DO EXPECT SOME MVFR CONDITIONS
UNDER THE STORMS IF THE MOVE ACROSS A TAF STATION.


&&

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

$$

SHORT TERM...JJ
LONG TERM...ABE
AVIATION...JJ