Severe Thunderstorm Warning 35, NWS Jackson, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
340 PM EDT THU MAY 4 2000

LITTLE CHANGE SINCE YESTERDAY...EXCEPT THAT THE WARM AND RATHER
HUMID AIR MASS IS NOW FULLY IN PLACE ACROSS THE FORECAST AREA. UPPER
LEVEL LOW CONTINUES NEARLY STATIONARY ALONG THE OK/AR BORDER WITH
RIDGING OVER THE SOUTHEAST UNITED STATES. ATMOSPHERE IS MOIST AND
UNSTABLE WITH LITTLE IN THE WAY OF A CAP. HOWEVER...THERE ARE NO
SIZEABLE FEATURES TO FOCUS CONVECTION EITHER. SCATTERED SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED THIS AFTERNOON...DESPITE THE FACT THAT
THERE HAS BEEN SUBSTANTIAL CLOUDINESS.

CONVECTION DID PERSIST LONGER THAN ANTICIPATED LAST NIGHT DUE TO
DIVERGENCE ALOFT IN A DEFORMATION ZONE. SUCH SUPPORT FOR CONTINUING
CONVECTION IS NOT PRESENT TONIGHT. WILL CALL FOR SCATTERED SHOWERS/STORMS
TO END THIS EVENING. UNTIL THEY DISSIPATE...LOCALLY HEAVY RAINFALL
WILL BE POSSIBLE DUE TO WEAK WIND FIELDS RESULTING IN SLOW MOVING
STORMS. MODELS AGREE ON MID/UPPER LEVEL MOISTURE DROPPING OFF
TONIGHT. WITH LOSS OF HEATING...CUMULUS SHOULD ALSO DISSIPATE. WITH
DECREASING CLOUDS...LIGHT WINDS...AND MOIST AIR MASS...WILL EXPECT
VALLEY FOG (DENSE IN SOME AREAS...ESPECIALLY WHERE IT RAINED).

FRIDAY SHOULD BRING MORE SUNSHINE THAN TODAY. NO CHANGE IN LOW LEVEL
AIR MASS IS EXPECTED. ALTHOUGH THERE IS STILL NO SUPPORT FOR
ORGANIZED CONVECTION...ANY DOWNWARD VERTICAL MOTION SHOULD ALSO BE
VERY WEAK. ADDITIONAL HEATING FROM INCREASED SUNSHINE LOOKS LIKE IT
COULD EASILY LEAD TO SCATTERED SHOWERS/STORMS POPPING UP AGAIN.
THINK THAT NGM MOS POP IS TOO LOW. WILL GO WITH A 30 POP AREA WIDE.

FRIDAY NIGHT/SATURDAY SHOW NO APPRECIABLE CHANGE FROM TONIGHT/FRIDAY
AND WILL AGAIN CARRY A 30 POP ON SATURDAY AFTERNOON.

NGM MOS TEMPS LOOK CLOSE OR SLIGHTLY TOO WARM (ESPECIALLY THE 88 AT
5I3 ON FRIDAY).

EXTENDED FORECAST...UPPER LOW OVER SOUTH CENTRAL U.S. IS EXPECTED TO
CONTINUE WEAKENING AND FINALLY START TO MOVE EAST AS NEXT TROF IN
MAIN WESTERLIES DROPS INTO MIDDLE OF THE NATION EARLY IN THE WEEK.
REMNANTS OF THE SOUTH CENTRAL U.S. LOW COULD PROVIDE AN INCREASED
CHANCE OF CONVECTION BY MONDAY. NO CHANGE IN AIR MASS EXPECTED UNTIL
MIDWEEK WHEN NEXT SIGNIFICANT UPPER TROUGH DROPS SOUTHEAST...WITH
ABOVE NORMAL TEMPS CONTINUING UNTIL THEN. COLD FRONT PASSAGE NOW SHOWN
BY MRF AND ECMWF TUESDAY NIGHT. HOWEVER...THE TREND FOR SLOWING THE
FRONT CONTINUES FOR A NUMBER OF MODEL RUNS. WILL INCLUDE A DAY TO
DAY CHANCE OF SHOWERS/STORMS IN THE EXTENDED FORECAST...BUT WILL NOT
DIFFERENTIATE A BETTER CHANCE OF PRECIP FOR ANY PARTICULAR DAY AT
THIS TIME.

.JKL...NONE

HAL