Flash Flood Warning 27, NWS Morristown, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KNOXVILLE/TRI-CITIES TN
820 PM EDT SAT MAY 31 1997

MRX WSR-88D IS SHOWING A LARGE AREA OF SHOWERS AND THUNDERSTORMS
MOVING NORTH ACROSS THE PLATEAU...SOUTHEAST TENNESSEE...SOUTHWEST
NORTH CAROLINA...AND CENTRAL TENNESSEE VALLEY. SOME OF THE RAIN
HAS BEEN QUITE HEAVY WITH THE CHA ASOS REPORTING OVER 1.6 INCHES
OF RAIN DURING THE PAST 3 HOURS. THE AREA OF RAIN IS HAVING A HARD
TIME MOVING NORTHEAST INTO NORTHEAST TENNESSEE AND SOUTHWEST
VIRGINIA.

BELEIVE THE AREA OF RAIN WILL EVENTUALLY MOVE INTO THESE
AREAS LATER THIS EVENING. HOWEVER...MRX VWP IS SHOWING WEAK-
MODERATE SOUTHEAST WINDS INTO THE NORTHEAST SECTIONS OF THE FORECAST
AREA WHICH WILL KEEP PCPN AMOUNTS DOWN CONSIDERABLY DUE TO DOWNSLOPE
WINDS. I DO NOT FEEL NORTHEAST TENNESSEE OR SOUTHWEST VIRGINIA WILL
EXPERIENCE ANY RUNOFF PROBLEMS DUE TO THE DOWNSLOPE FLOW.

GREATEST THREAT FOR FLASH FLOODING WILL BE ACROSS THE PLATEAU AND
SOUTHEAST TENNESSEE DUE TO THE PERSISTENT LO LVL CONVERGENCE...
UPSLOPE FLOW...AND MAX UPR DIFL. CURRENT TEMP FCST LOOKS GOOD...BUT
WOULD RECOMMEND CHGG WIND FCST TO VARIABLE FOR CHA AND CSV AREAS.

WATER VAPOR LOOP SHOWS A WELL DEFINED DRY SLOT WRAPPING EAST NORTHEAST
ACROSS MS INTO AL. ETA MODEL SHOWS THIS MID-LVL DRYING MOVING INTO THE
FORECAST AREA FOR SUNDAY. FEEL SHOWER AND STORMS WILL DIMINISH OVER
THE REGION IN THE MORNING WITH SKIES BECOMING BRIEFLY PARTLY CLOUDY
AROUND NOON TOMORROW. MODELS ALSO SHOW A GOOD DEAL OF MID-LVL COOLING
AS COLD POOL ALOFT APPROACHES THE AREA WITH NGM DEPICTING BEST
LIFTED INDICES DROPPING DOWN TO -10 IN THE AFTERNOON. ETA MODEL ALSO
SHOWS WEAK-MODERATE LO LVL CONVERGENCE OVER THE REGION...ESPECIALLY
THE NORTHERN HALF OF THE FA. I STG/SVR STMS TO DEVELOP OVER THE
REGION BY MID/LATE AFTERNOON WITH MAIN THREAT BEING DAMAGING
DOWNBURSTS WINDS AND LARGE HAIL.

FEEL MIDNIGHT SHIFT WILL NEED TO CONSIDER RAISING POPS FOR SUNDAY AND
INCLUDING POSSIBLY SVR IN THE FCST. ALSO...FEEL CURRENT FCST HIGHS
FOR TOMORROW ARE TOO LOW...PER ETA MODEL DEPICTION OF 15 CELCIUS
850 MB TEMPS OVER THE AREA SUNDAY AFTERNOON.

DH