Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 262017
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
417 PM EDT TUE MAY 26 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 417 PM EDT TUE MAY 26 2015

SHOWERS AND THUNDERSTORMS WERE DEVELOPING IN A BAND SPANNING
THROUGH CENTRAL KY EARLY THIS AFTERNOON...BEING AIDED BY A
SHORTWAVE TROUGH PASSING TO OUR NW. IF EITHER INSTABILITY OR SHEAR
HAD BEEN A BIT STRONGER...A STRONGER SEVERE THREAT MAY HAVE BEEN
REALIZED THIS AFTERNOON. HOWEVER...THE BETTER SHEAR IS TO OUR
NORTH...AND OUR CAPE PROFILE HAS BEEN THIN ABOVE ABOUT 17K FEET.
THINK THAT IF ANY SEVERE WX OCCURS...IT WILL BE LIMITED IN
SCOPE...AND MAINLY A WIND THREAT. THE BAND OF SHOWERS AND STORMS
SHOULD PROGRESS EAST ACROSS THE JKL FORECAST AREA THIS
EVENING...BUT BE ON A DIMINISHING TREND SHORTLY AFTER A LOSS OF
HEATING.

MODELS SUGGEST THAT OUR MID/UPPER LEVELS WILL BE QUITE A BIT DRIER
ON WEDNESDAY IN THE WAKE OF THE SYSTEM TONIGHT. THIS WILL ALLOW
FOR SUNSHINE AND STRONG HEATING. HOWEVER...DRY AIR ENTRAINMENT
INTO CONVECTIVE CURRENTS AND A LACK OF SIGNIFICANT UPPER LEVEL
SUPPORT SHOULD LIMIT PRECIP. HAVE ONLY USED 20-30 PERCENT
POPS...AND EVEN THAT IS ABOVE MOS GUIDANCE.

MODELS SHOW ANOTHER SHORTWAVE TROUGH PASSING IN THE FLOW ALOFT ON
WEDNESDAY NIGHT. IT WILL BE AT AN UNFAVORABLE TIME FOR PRECIP IN
THE DIURNAL PATTERN. HAVE USED A MODEST INCREASE IN POPS FOR LATE
WEDNESDAY NIGHT...BUT ONLY IN CHANCE CATEGORY.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 342 PM EDT TUE MAY 26 2015

HIGH PRESSURE WILL RESIDE JUST OFF THE ATLANTIC COAST/WESTERN
ATLANTIC DURING THE EXTENDED...WHILE LONGWAVE TROUGHING REMAINS
ACROSS THE REMAINDER OF THE CONUS. MULTIPLE SHORTWAVES ARE STILL
PROJECTED TO MOVE ALONG THIS LONGWAVE PATTERN...EJECTING TOWARDS THE
OHIO RIVER VALLEY THROUGHOUT THE PERIOD. STRONG SW FLOW ACROSS THE
REGION WILL KEEP TEMPERATURES IN THE LOW TO MID 80 RANGE. AND WITH
SURFACE WINDS VARYING BETWEEN THE SW AND SE...EXPECT LARGE AMOUNTS
OF MOISTURE TO FLOW IN OFF THE GOLF OF MEXICO. AS A RESULT...ANY
SHORTWAVE WHICH PASSES ACROSS THE OHIO RIVER VALLEY WILL LIKELY
SPARK SHOWERS AND THUNDERSTORMS EACH DAY THROUGHOUT THE EXTENDED.
BEST COVERAGE WILL BE DURING THE AFTERNOON AND EVENING HOURS...WHEN
PEAK HEATING HELPS INITIATE BEST INSTABILITY...THEN DIMINISH
OVERNIGHT AS WE LOSE THIS DRIVING FORCE. MODELS CONTINUE TO LEAVE
INFLATED AMOUNTS OF MOISTURE/PRECIP IN DURING THE OVERNIGHT HOURS
AFTER THE LOSS OF INSTABILITY...SO CUT BACK MODEL BLEND TO BETTER
REFLECT POTENTIAL FOR NIGHT TIME CONVECTION...GENERALLY LEAVING IN
ONLY SLIGHT TO LOW END CHANCE POPS.

A COLD FRONT WILL LIKELY NEAR THE REGION FROM THE NW DURING THE DAY
SATURDAY...WHICH WILL BRING OUR BETTER CHANCE FOR THUNDERSTORMS AND
MAYBE SOME STRONGER CONVECTIVE ACTIVITY BOTH SATURDAY AND SUNDAY.
ALONG AND JUST BEHIND THE FRONT /GENERALLY SUNDAY AND SUNDAY
NIGHT/...SURFACE WINDS WILL BECOME MORE NORTHERLY...BUT OVERALL
MOISTURE WILL REMAIN IN PLACE. WITH SUCH A SET UP...RAIN WILL BE
CERTAIN WITH LITTLE INSTABILITY AT THE SURFACE TO PROMOTE
THUNDERSTORMS. HOWEVER...COULD NOT RULE OUT SOME ELEVATED
CONVECTION...ESPECIALLY IN SOME OF THE HEAVIER SHOWERS AND WITH A
BOUNDARY SO NEARBY...SO LEFT IN MENTION OF THUNDER FOR THIS TIME
FRAME. SOUTHERLY WINDS WILL RETURN BY MONDAY...WITH THE BOUNDARY
RETURNING AND HELPING TO PROMOTE MORE THUNDERSTORM ACTIVITY TO ROUND
OUT THE EXTENDED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 318 PM EDT TUE MAY 26 2015

SHOWERS AND THUNDERSTORMS WERE ON THE INCREASE AS THE PERIOD
STARTED...ESPECIALLY TO OUR NORTH AND WEST. THE GREATER
CONCENTRATION OF SHOWERS AND THUNDERSTORMS SHOULD PROGRESS
EASTWARD INTO THE JKL FORECAST AREA DURING THE LATE AFTERNOON AND
EVENING. A DIMINISHING TREND IS EXPECTED AS THE AREA OF PRECIP
CROSSES EASTERN KENTUCKY THIS EVENING AND EVENTUALLY EXITS TO THE
EAST LATE TONIGHT. MVFR CAN BE EXPECTED AT TIMES WITH THE
PRECIP...AND POSSIBLY LOCALIZED IFR IN THE HEAVIEST PRECIP. AFTER
A RELATIVE LULL IN PRECIP WEDNESDAY MORNING...SOME RENEWED
DEVELOPMENT MAY TAKE PLACE AS DIURNAL HEATING OCCURS TOWARD THE
END OF THE PERIOD. HOWEVER...CONFIDENCE IS TOO LOW TO WARRANT ANY
INCLUSION IN TAFS ON WEDNESDAY.


&&

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

$$

SHORT TERM...HAL
LONG TERM...JMW
AVIATION...HAL


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