Severe Thunderstorm Warning 187, NWS Morristown, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KNOXVILLE/TRI-CITIES TN
200 PM EDT FRI JUN 20 1997

SATELLITE LOOP CONTINUES TO SHOW A WEAK S/WV/SHEAR AXIS ACROSS THE
FORECAST AREA WITH SLIGHTLY COOLER AIR ALOFT (500 MB TEMPS BETWEEN -10
AND -11).  THE COOL POOL ALOFT HAS HELPED PRODUCE A VERY UNSTABLE
ENVIROMENT WITH CAPES OF 1800-2200 J/KG WITH LIFTED INDICES OF -6 TO
-8. EVEN WITH NO SIGNIFICANT LO LVL CONVERGENCE...  SCT THUNDERSTORMS
HAVE DEVELOPED OVER THE TERRAIN FEATURES AND EXPECTED SOME OF THESE
STORMS TO CONTINUE TO MOVE INTO THE VALLEY THIS EVENING.  WOULD CALL
FOR A CHC OF THUNDERSTORMS UNTIL AROUND MIDNIGHT AREA-WIDE.

ATL/BNA SOUNDINGS ALSO SHOW DISTINCT MID-LVL DRY AIR (ESPLY ATL) WITH
DELTA-K OF 25-30...SO ISOLATED DAMAGING WET MICROBURSTS WILL AGAIN BE
A CONCERN FOR LATE THIS AFTERNOON AND EVENING. WINDEX PROGRAM YIELDS
MICROBURSTS POTENTIAL OF 58 KNOTS. RELATIVELY HIGH WBZ SUGGESTS ONLY
MARGINAL SVR HAIL POSSIBLE. ALSO...THE SLOW MOVEMENT OF THE STORMS MAY
PRODUCE LOCALLIZED FLASH FLOODING.

THESE WEAK S/WV WILL MEANDER SLOWLY NE ACROSS THE SRN APPALACHIANS THE
NEXT 48 HOURS CONTINUING THE CHC OF MAINLY AFTERNOON AND EVENING
THUNDERSTORMS. AGAIN SOME OF THESE STORMS WILL HAVE THE THREAT FOR
PRODUCING DAMAGING DOWNBURSTS WINDS AND LOCALLIZED FLASH FLOODING.
WOULD CALL FOR 30-40 PERCENT POPS WITH HIGHER POPS OVER THE EASTERN
TENNESSEE MOUNTAINS. BESIDES THE STORMS...PARTLY CLOUDY SKIES ARE
ANTICIPATED WITH PERSISTENT GENERALLY THE BEST TEMPERATURE FCST.
ALSO...PATCHY MORNING DENSE FOG IS ANTICIPATED...ESPECIALLY WHERE
LATE AFTERNOON/EVENING STORMS OCCUR.

AS FOR TEMPS...GUIDANCE CLOSE AND REASONABLE.

DH