693 
FXUS63 KJKL 061956
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
356 PM EDT TUE AUG 6 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 350 PM EDT TUE AUG 6 2013

AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS CENTERED OVER SOUTH TX AS
OF MID AFTERNOON WITH WEST NORTHWEST FLOW ACROSS THE OH VALLEY
BETWEEN A TROUGH MOVING OFF THE EASTERN SEABOARD AND THE RIDGE.
ANOTHER COUPLE OF SHORTWAVES WERE UPSTREAM...ONE WORKING ACROSS THE
NB/KS AREA AND ANOTHER WORKING OVER THE NORTHERN ROCKIES. AS OF MID
AFTERNOON THERE IS STILL PLENTY OF CLOUD COVER ACROSS THE OH VALLEY.
SOME OF THIS APPEARS TO BE ASSOCIATED WITH AN MCV WORKING ACROSS THE
LOWER OH VALLEY. THIS CLOUD COVER HAS SUPPRESSED TEMPS TODAY...ESPECIALLY
OVER THE CENTRAL AND WESTERN CWA. PORTIONS OF THE BIG SANDY REGION
ARE WARMEST AT PRESENT AS BREAKS HAVE BEEN MORE CONSISTENT THERE. AT
THE SFC...AN AREA OF LOW PRESSURE WAS OVER TX/OK PANHANDLE AREA WITH
A WARM FRONT EAST AND THEN BECOMING STATIONARY TO SFC LOW PRESSURE IN
MS ASSOCIATED WITH THE MCV. 

THE MCV WORKING ACROSS THE LOWER OH VALLEY REGION SHOULD PASS INTO
MIDDLE TN AND TO OUR SW THROUGH TONIGHT WITH THE NEXT UPSTREAM
SHORTWAVE REACHING THE LOWER OH VALLEY REGION LATE TONIGHT.
CONVECTION WITH THE MCV SHOULD GENERALLY STAY SOUTH AND WEST OF THE
JKL CWA BUT MAY BRUSH THE TN BORDER COUNTIES LATE THIS AFTERNOON AND
THIS EVENING. OTHERWISE...ISENTROPIC LIFT FROM THE NEXT APPROACHING
SHORTWAVE AND A WARM FRONT LIFTING TOWARD THE OH VALLEY REGION AS THE
LOW PRESSURE OVER THE PLAINS MOVES NORTHEAST SHOULD LEAD TO FURTHER
DEVELOPMENT OF CONVECTION TONIGHT. AT THE SAME TIME...A MORE POWERFUL
SHORTWAVE WILL BE WORKING TOWARD THE WESTERN GREAT LAKES REGION. AN
AREA OF LOW PRESSURE ASSOCIATED WITH IT SHOULD TRACK TOWARD THE JAMES
BAY REGION THROUGH LATE WED AFTERNOON WITH THE TRAILING COLD FRONT
APPROACHING THE OH VALLEY REGION AND SOUTHERN PLAINS AND SLOWING
DOWN. THE BOUNDARY SHOULD REMAIN TO THE NORTH AND WEST OF THE AREA
THROUGH THE END OF THE PERIOD.

THERE REMAINS MODEL DIFFERENCES IN THE EVOLUTION AND TIMING OF
CONVECTION LATER TONIGHT AND FOR MOST OF THE PERIOD FOR THAT MATTER.
AS MENTIONED EARLIER...THE HIGHEST CHANCES THIS EVENING APPEAR TO BE
NEAR THE TN BORDER IN THE CUMBERLAND VALLEY AND LAKE CUMBERLAND
REGIONS. THE MODEL CONSENSUS ALSO APPEARS TO FAVOR THE SOUTHWEST CWA
LATER TONIGHT AND THEN FURTHER EAST ACROSS THE REMAINDER OF THE AREA
AS THE WEAK SFC SYSTEM TRACKING TO OUR NORTHWEST BECOME DIFFUSE AND
MORE OR LESS MERGES WITH THE APPROACHING FRONT. AT THE SAME TIME...AT
LEAST ONE OR TWO WEAK SHORTWAVES ARE PROGGED TO WORK ACROSS THE AREA
AND ANY DAYTIME HEATING MIGHT LEAD TO THE POTENTIAL FOR A STRONGER
STORM OR TWO...ESPECIALLY IN THE NORTHWEST. PW SHOULD CLIMB A BIT
ABOVE NORMAL TOWARD TWO INCHES ON WED AND ANY THUNDERSTORMS ON WED OR
WED NIGHT COULD BRING LOCALLY HEAVY RAIN. 

THE PASSING SHORTWAVE AND WARM FRONT WORKING INTO THE AREA AS WELL AS
DAYTIME HEATING ALL POINT TOWARD THE HIGHEST CHANCES FOR SHOWERS AND
THUNDERSTORMS DURING THE PERIOD ON WED AS OPPOSED TO TONIGHT OR ON
WED NIGHT.

WITH PLENTY OF CLOUD COVER...AND DEWPOINTS INCREASING THROUGH THE
60S MIN T TONIGHT SHOULD LEAD TO ABOVE NORMAL TEMPS FOR TONIGHT IN
THE UPPER 60S TO AROUND 70. FOR MAX T ON WED...WE STAYED BELOW THE
MAV WHICH HAS BEEN TOO WARM FOR MAX T AND LEANED CLOSER TO
PERSISTENCE AND THE MODEL CONSENSUS. THE MET NUMBERS WERE THE COLDEST
AND IF CLOUDS ARE VERY PERSISTENT COULD VERIFY. 

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 354 PM EDT TUE AUG 6 2013

THE LONG TERM DISCUSSION WILL BE ISSUED SHORTLY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 225 PM EDT TUE AUG 6 2013

HIGH PRESSURE CONTINUES TO SHIFT EASTWARD AWAY FROM THE REGION AS
LOW PRESSURE SYSTEM BEGINS TO APPROACH THE AREA. A LARGE AREA OF
CLOUDS ENCOMPASSES THE OHIO RIVER VALLEY REGION AND POINTS WEST AS A
DISTURBANCE IS DROPPING INTO THE TN VALLEY. DESPITE THE BKN/OVC
SKIES...CONDITIONS SHOULD REMAIN VFR THROUGH AT LEAST 0Z. THERE ARE
SOME UPSTREAM MVFR OBS AND SOME OF THIS SPREADING INTO SME BEFORE 0Z
IS CERTAINLY POSSIBLE. THE EXACT TIMING AND DEGREE TO WHICH THIS
LOWERING OCCURS IS STILL SOMEWHAT UNKNOWN...BUT IT SHOULD OCCUR IN
MOST LOCATIONS BETWEEN 2Z AND 12Z AS CONVECTION DEVELOPS AND WORKS
TO THE TAF SITES. CONFIDENCE IN THIS IS A BIT HIGHER AT LOZ AND SME
AS COMPARED TO JKL. ONCE CONDITIONS FALL TO MVFR THEY SHOULD REMAIN
THERE THROUGH THE END OF THE PERIOD AS CONVECTION WORKS ACROSS THE
AREA.


&&

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

$$

SHORT TERM...JP
LONG TERM...GEOGERIAN
AVIATION...JP