Flash Flood Warning 9, NWS Jackson, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
255 PM EDT WED APR 28 1999

18Z SFC ANALYSIS SHOWS LOW PRESSURE DROPPING INTO CENTRAL TENNESSEE.
THIS IS BECOMING AN INVERTED TROUGH WITH A WARM FRONT RUNNING NORTHEAST
ACROSS NORTHERN KENTUCKY AND BACK DOWN THE SPINE OF THE APPALACHIANS.
THIS TWIST IS IN RESPONSE TO HIGH PRESSURE BUILDING OVER THE NORTHEAST
AND DOWN SOUTH ALONG THE EASTERN SLOPES.

PWS OVER AN INCH...CAPES OF 1000 TO 2000 J/KG...A MIDLEVEL SPEED MAX...
AND WEAK STEERING CURRENTS ARE MAKING FOR POTENTIAL FLASH FLOODING FROM
ANY OF THE STRONGER CELLS. THIS ACTIVITY WILL CONTINUE WELL INTO THE
EVENING SUPPORTED BY PLENTY OF UPPER LEVEL DIVERGENCE INITIALLY FROM
THE DYING CLOSED LOW/S WEST TO EAST JET AND THEN LATER FROM THE
BUILDING NORTHEAST LOW/S NORTHEAST TO SOUTHWEST JET AT 300 MB.  THUS
THREAT OF HEAVY RAIN AND THUNDERSTORMS WILL CONTINUE INTO THE
OVERNIGHT.

THE MODELS ARE IN DECENT AGREEMENT WITH THE BUILDING OMEGA BLOCK AND
SACRIFICIAL UPPER LOW FILLING OVER SOUTHERN ILLINOIS. LOW PRESSURE WILL
BECOME INVERTED TONIGHT OVER THE TENNESSEE VALLEY. DURING THE DAY
THURSDAY CONDITIONS WILL IMPROVE FROM NORTH TO SOUTH AS BROAD HIGH
PRESSURE EASES INTO TO THE AREA. HIGH PRESSURE WILL BE FIRMLY IN
CONTROL AT THE SFC ON FRIDAY WITH THE RIDGE STILL TO OUR WEST. THIS
WILL SET UP A PLEASANT AND DRY WEEKEND AS THE RIDGE SLOWLY MOVES EAST.

AS FOR FORECAST SPECIFICS...SHOWERS AND THUNDERSTORMS TONIGHT WITH
HEAVY RAIN POSSIBLE. THURSDAY SHOWERS END FROM NORTH TO SOUTH AS THE
HIGH EDGES INTO THE STATE. SOME CLEARING LATE TO THE NORTH. THURSDAY
NIGHT CLEARING THROUGHOUT WITH AREAS OF FOG FORMING WHEN THE CLOUDS
LEAVE. FRIDAY WILL BE DRY...PLEASANT AND PARTLY SUNNY...ALLOWING FOR
THE FOG TO BURN OFF AND ANY CU POPPING OVER THE MOUNTAINS.

AS FAR AS THE NUMBERS GO...WILL GO A BIT HIGHER ON OVERNIGHT LOWS...
ESPECIALLY SOUTH WHERE THE CLOUDS WILL BE THICKEST. OTHERWISE...THE FAN
AND FWC NUMBERS LOOK GOOD.

.JKL...NONE.

GREIF