Damaging Wind in Tennessee, July 25, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
315 PM EDT THU JUL 25 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
315 PM EDT THU JUL 25 2002

CURRENT SURFACE ANALYSIS INDICATES THAT THE STATIONARY FRONT OVER THE
FORECAST AREA FROM YESTERDAY HAS WASHED OUT. CURRENT RADARS ARE
REVEALING A BETTER COVERAGE OF CONVECTION COMPARED TO YESTERDAY...
BUT THIS SHOULD RAPIDLY DIMINISH AFTER SUNSET. A VERY MOIST AND
MODERATELY UNSTABLE AIRMASS WILL CONTINUE ACROSS THE FORECAST AREA
THROUGH THE WEEKEND...ALTHOUGH A DEVELOPING UPPER-HIGH SHOULD
DECREASE THE COVERAGE OF CONVECTION EACH SUCCESSIVE AFTERNOON. EXPECT
THAT MOST CONVECTION EACH AFTERNOON AND EVENING SHOULD MAINLY BE
CONFINED TO THE HIGHER ELEVATIONS.

IN THE EXTENDED...UPPER-LEVEL HIGH IS PROGGED TO BUILD ACROSS THE
SOUTHEAST U.S. SUNDAY THROUGH TUESDAY. THIS WILL ALLOW WARMER TEMPS
TO DEVELOP AND SHOULD INHIBIT CONVECTION EVERYWHERE EXCEPT ACROSS
THE MOUNTAINS. ANOTHER WEAK COLD FRONT IS EXPECTED TO APPROACH THE
FORECAST AREA ON WEDNESDAY...BUT WILL PROBABLY STALL OUT JUST SOUTH
OF THE OHIO VALLEY. HOWEVER...WILL CONTINUE WITH A LOW CHANCE POP ON
WEDNESDAY AND THURSDAY WITH THE UPPER-LEVEL HIGH EXPECTED TO WEAKEN.

AS FOR TEMPS...NO MOS GUIDANCE TO WORK WITH THIS AFTERNOON...BUT WILL
NOT MAKE MANY TWEAKS TO PREVIOUS FORECAST. A PERSISTENCE FORECAST
LOOKS TO BE THE WAY TO GO...SINCE LOCAL AIRMASS WILL NOT CHANGE
MUCH THROUGH THE PERIOD.

THE FOLLOWING NUMBERS ARE PRELIMINARY AND FOR COORDINATION ONLY:

CHA   72  90  72  92 /  30  20  20  20
TYS   70  88  70  90 /  30  20  20  20
TRI   67  85  67  87 /  30  20  20  20
OQT   70  88  70  90 /  30  20  20  20

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

DMG

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MIDDAY FORECAST DISCUSSION (UPDATE)
955 AM EDT THU JUL 25 2002

MODEL TIME HEIGHTS SHOW GOOD MOISTURE PROFILE ESPECIALLY AT THE
LOWER LEVELS. THIS IN CONJUNCTION WITH MODERATE INSTABILITY PROJECTED
FOR THIS AFTERNOON AND A POORLY-DEFINED BOUNDARY STILL IN OUR GENERAL
VICINITY ALL ARGUE FOR SCATTERED CONVECTION TO DEVELOP IN THE
DAYTIME HEATING. HOWEVER...MORNING CLOUD COVER HAS INHIBITED SURFACE
HEATING SO FAR. EXPECT THE CLOUDS TO EVENTUALLY ERODE AND ALLOW
SUFFICIENT SURFACE HEATING FOR SCATTERED CONVECTION TO DEVELOP.
THEREFORE WILL REMOVE MORNING FOG FROM ZONES BUT OTHERWISE LEAVE AS
IS.

LCM

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MORNING FORECAST DISCUSSION
345 AM EDT THU JUL 25 2002

SFC FRONT LIES ASTRIDE THE CWA FROM NE-SW, BUT IS VERY DIFFUSE. CUT-
OFF LOW OVER CWA AS WELL BUT BECOMING MORE DIFFUSE WITH TIME. GREAT
LAKES UPPER TROF WILL DEEPEN OVERHEAD THROUGH FRIDAY MORNING THEN
FLATTEN OUT AND MOVE EAST. AS TROF TEMPORARILY DEEPENS, ATLANTIC
RIDGE IS SUPPRESSED AND SAUNTERS EAST, TOO. FAR WESTERN TROF IS THEN
ALLOWED TO SLIDE EAST. SERIES OF PRETTY MINOR SHORTWAVES WILL DROP
INTO SE U.S. FROM NORTHERN PLAINS THROUGH SATURDAY. THEN WESTERN TROF
STRENGTHENS OVER CANADA AND DEEPENS TO AFFECT THE MID SOUTH AROUND
MIDDLE OF NEXT WEEK.

MORE PERSISTENCE SEEMS TO BE A GOOD IDEA WITH THE NEAR TERM FORECAST
AS MOISTURE, AND SOMEWHAT UNSTABLE AMS IN PLACE REALLY HAS NO REASON
TO GO ANYWHERE. CHANCE POPS HAS WORKED NICELY OVER ENTIRE AREA WITH
SIMILAR FEATURES THE LAST WEEK SO WILL STAY THE COURSE. BY FRIDAY,
THOUGH, UPPER COOL (WHICH HAS BEEN THE ONLY REAL UPPER SUPPORT FOR
CONVECTION) FILLS IN AND AS A RESULT WILL DROP POPS FRIDAY AND
FRIDAY NIGHT TO SLIGHT CHANCE.

COUPLE OF CHANGES TO ZONE PACKAGE: COMBINED SOUTHERN TN-NC STATE
LINE MOUNTAIN ZONE WITH SMOKY MOUNTAIN ZONE AS ENOUGH SIMILARITY TO
WARRANT. ALSO, UPPED POPS FOR SATURDAY AND SATURDAY NIGHT TO 30 OVER
ENTIRE FORECAST AREA. BEYOND THAT, NEXT GOOD CHANCE REALLY FOR
PRECIP STARTS TUESDAY AND INCREASED INTO WEDNESDAY. BUT THAT IS SO
FAR OUT IN TIME, WILL LIKELY HAVE TO REFINE AS WE GET CLOSER.

THE FOLLOWING NUMBERS ARE PRELIMINARY AND FOR COORDINATION ONLY:

CHA   88  69  91  72 /  40  40  20  20
TYS   87  70  90  70 /  40  40  20  20
TRI   86  67  87  68 /  40  40  20  20
OQT   87  69  90  69 /  40  40  20  20

BB

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EVENING FORECAST DISCUSSION (UPDATE)
1010 PM EDT WED JUL 24 2002

CONVECTION HAS JUST ABOUT ENDED...EXCEPT FOR OVER SWRN VA NEAR THE
WEAKENING COLD FRONT.  WILL UPDATE AND REMOVE MENTION OF TSRA IN
MOST AREAS.  PATCHY FOG STILL SEEMS LIKELY OVERNIGHT...AND MIN TEMP
FORECAST LOOKS GOOD.

TG

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EARLY EVENING FORECAST DISCUSSION (UPDATE)
715 PM EDT WED JUL 24 2002

LATE START FOR CONVECTION TODAY AND APPARENT LACK OF ANY UPPER LEVEL
SUPPORT IS HINDERING MUCH DEVELOPMENT THIS EVENING.  BETTER COVERAGE
REMAINS OFF TO OUR EAST OVER WESTERN NC...WHILE ALMOST SCATTERED
TSRA OVER NE PLATEAU COUNTIES AND SWRN VA...BUT ONLY ISOLATED TSRA
ELSEWHERE.  WEAK WINDS ALOFT ARE RESULTING IN NEARLY STATIONARY TSRA
AT THIS TIME.

MAY UPDATE ZONES BEFORE 8PM EDT AND LOWER RAIN CHANCES FOR REST OF
THE EVENING...FOLLOWED BY A LATE UPDATE ONCE ALL CONVECTION
DISSIPATES.

TG