Severe Thunderstorm Warning 197, NWS Morristown, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
255 PM EDT THU AUG 1 2002

THE FOLLOWING ARE ALL THE FORECAST DISCUSSIONS FROM THE PAST 24
HOURS...WITH THE MOST RECENT ON TOP. THIS PROVIDES A HISTORY OF THE
DEVELOPMENT OF THE CURRENT FORECAST.

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AFTERNOON FORECAST DISCUSSION
250 PM EDT THU AUG 1 2002

LARGE UPPER RIDGE OF HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE
SOUTHERN APPALACHIANS THE NEXT COUPLE DAYS PRODUCING TYPICAL
HOT...HAZY AND HUMID CONDITIONS FOR EARLY AUGUST.  ONLY LIFTING
MECHANISM FOR CONVECTION WITH BE LOCAL TERRAIN FEATURES...SO
WILL CONTINUE CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS FOR
FAR EASTERN TENNESSEE MOUNTAINS AND SOUTHWEST NORTH CAROLINA
FOR FRIDAY.

ISOLATED STORMS REMAINS POSSIBLE AGAIN FRIDAY...BUT LIMITED
COVERAGE EXPECTED...SO WILL KEEP AREA DRY FOR SATURDAY.

WILL TREND HIGHS TOWARD THE HOTTER MOS VALUES

FCSTID =
CHA   71  95  71  94 /   0  10  10  10
TYS   70  94  70  94 /   0  10  10  10
TRI   64  91  65  91 /   0  10  10  10
OQT   68  94  68  94 /   0  10  10  10

.MRX...
NC...NONE.
TN...NONE.
VA...NONE.

DH

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MORNING FORECAST DISCUSSION
940 AM EDT THU AUG 1 2002

LARGE RIDGE OF HIGH PRESSURE REMAINS ACROSS THE CENTRAL/SOUTHERN
PLAINS EAST INTO THE OHIO VALLEY WITH THE FORECAST AREA ON THE
FAR EASTERN EXTENT OF THE RIDGE.  PER SPC DISC...A WEAK WAVE IS
MOVING SOUTH ACROSS VA THIS MORNING AND WILL BE ACROSS THE FORECAST
AREA THIS AFTERNOON/EVEG. SOME LIFT EVIDENT WITH THIS WAVE WITH
THE AVN THE STRONGEST.  AIRMASS IS PROGGED TO BECOME MODERATELY
UNSTABLE WITH CAPES NEAR 2500 J/KG AND LIS BETWEEN -5 AND -7.

BOUNDARY LAYER IS PROGGED TO MOISTEN DURING THE DAY WITH PWS
INCREASING FROM 1.24 TO NEARLY 1.5 INCHES AND K INDICES IN THE
UPPER 30S BY AFTERNOON.  FORECAST SOUNDINGS SHOW GOOD MID-LEVEL
DRY INTRUSION WITH INVERTED-V SIGNATURE...SO THERE IS A DAMAGING
MICROBURST POTENTIAL.

WILL CALL FOR SCATTERED THUNDERSTORMS FOR THE MOUNTAINS TODAY WITH
A SLIGHT CHANCE FOR THE VALLEY. WILL CHANGE SKY COVER FROM MOSTLY
SUNNY TO PARTLY CLOUDY.  WILL MAKE ONLY MINOR COSMETIC CHANGES TO
TEMPERATURE FORECAST.

DH

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EARLY MORNING FORECAST DISCUSSION
330 AM EDT THU AUG 1 2002

SURFACE RIDGE BUILDS INTO AREA FROM THE NORTH. UPR RIDGE BUILDS OVER
AREA FROM WEST. AS LOWER LVL RIDGE BUILDS IN...WEAK CONVERGENCE
WORKS SOUTHWARD DOWN EAST SIDE OF APPALACHIANS. WITH THE AID OF
UPSLOPE FLOW SCT TSTMS POSSIBLE ACROSS MNTS OF TN/NC NEXT COUPLE OF
DAYS. OTHERWISE MAX TEMPS BEGIN TO CLIMB. UPR RIDGE OVR
NATIONS HEARTLAND HOLD STRONG FOR SEVERAL DAYS. NORTHERN
WESTERLIES AND SOUTHERN EASTERLIES NOT LIKELY TO PENETRATE
SUFFICIENTLY FOR MUCH PRECIPITATION THESE PARTS. TROPICAL
SEASON POISED TO START CRANKING.

CHA AA 095/071 095/071 094 17111
TYS AA 093/071 093/069 094 17111
TRI AA 091/067 092/065 090 17011
OQT AA 092/069 093/068 094 17111=

SON
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EVENING UPDATE DISCUSSION.

THUNDERSTORMS HAVE ENDED IN THE FORECAST SO WILL UPDATE FORECAST TO
REMOVE WORDING.  NO OTHER CHANGES PLANNED.

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AFTERNOON FORECAST DISCUSSION
250 PM EDT WED JUL 31 2002

MAIN AREA OF CONVECTIVE DEVELOPMENT THIS AFTERNOON HAS BEEN OVER SE
TN INTO SW NC AND NRN GA...WHERE MSAS SHOWS BEST INSTABILITY AND
SOME WEAK LOW LEVEL CONVERGENCE HAS BEEN NOTED.  THUS...FOR
CONTINUITY AND TO BLEND WITH GFE NEIGHBORS I WILL ONLY CARRY SLIGHT
CHANCE POPS FOR THIS EVENING FOR SE TN (CHA) AND MY SRN MTN GROUP.
HOWEVER...I WOULD NOT RULE OUT AN ISOLATED SHRA OR TSRA ON THE
PLATEAU OR MY NE MTN GROUP...BUT THIS COULD EASILY BE COVERED IN A
SHORT TERM FORECAST.  BOUNDARY LAYER MOISTURE SHOULD BE HIGH AGAIN
TONIGHT...ALTHO GROUND MAY DRY A BIT WITH MID TO LATE AFTERNOON
SUNSHINE...SO INCLUDED PATCHY FOG.  MOS MINS LOOKED REASONABLE...BUT
WENT JUST A BIT ABOVE THE TRI NUMBERS DUE TO CURRENT DEWPOINTS AND
POSSIBLE FOG DEVELOPMENT.

OTHERWISE...FOR LATER PERIODS THERE IS GENERALLY A WARM AND DRYING
TREND AS RIDGE BUILDS EAST...AND THE UPPER LOW OVER SRN GA STAYS
MAINLY TO OUR S OR SW.  THIS UPPER LEVEL FEATURE...PLUS DAYTIME
HEATING CONVINCED ME TO KEEP IN SOME VERY LOW POPS FOR THURSDAY
AFTERNOON...THEN MAINLY DRY ELSEWHERE (EXCEPT 20% POPS FRIDAY IN SRN
MTNS).  THIS SEEMS REASONABLE AND ALSO MAINTAINS CONTINUITY WITH
CURRENT ZONES.  MOS TEMPS WERE CLOSE AND GENERALLY ACCEPTED.

EXTENDED...RIDGE DOMINATES FROM SATURDAY ON...AND ALSO NOTED WEAK
COLD FRONT OVER OHIO RIVER VALLEY MAY NOT EVEN REACH INTO OUR NRN
ZONES.  PRELIMINARY TEMPS AND POPS FOLLOW FOR COORDINATION PURPOSES:

FCSTID =
CHA   72  94  71  95 /  20  30  10  10
TYS   70  92  69  93 /  10  20  10  10
TRI   65  91  65  92 /  10  20  10  10
OQT   69  92  69  93 /  10  20  10  10

TG