Severe Thunderstorm Warning 129, NWS Morristown, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
300 AM EDT SUN MAY 11 2003

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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EARLY MORNING FORECAST DISCUSSION
300 AM EDT SUN MAY 11 2003

LINE OF CONVECTION ASSOCIATED WITH A COLD FRONT IS CURRENTLY MOVING
THROUGH WEST TENNESSEE. THIS ACTIVITY SHOULD MOVE INTO THE PLATEAU
COUNTIES JUST BEFORE 12Z THIS MORNING. STRONG DYNAMICS ASSOCIATED
WITH THIS FEATURE HAVE PROMPTED TORNADO WATCH BOXES ALONG AND
PRECEDING THE LINE. CATEGORICAL POPS SEEM APPROPRIATE FOR EARLY
IN THE FIRST PERIOD GIVEN THE CURRENT INTENSITY OF THE LINE. THE
PRECIP SHOULD END RAPIDLY AFTER 18Z AS THE COLD FRONT RACES THROUGH
THE FORECAST AREA.

GENERALLY BENIGN WEATHER CONDITIONS WILL SUCCEED THE FROPA THROUGH
MUCH OF THE UPCOMING WORK WEEK. THE PERSISTENT UPPER RIDGE WHICH HAS
RESULTED IN WELL ABOVE CLIMO TEMPS WILL BE REPLACED BY A LOW
AMPLITUDE TROUGH AND NORTHWESTERLY FLOW. TEMPS WILL TEND TO AVERAGE
SLIGHTLY BELOW CLIMATOLOGY THROUGH THE WEEK. NEXT SIGNIFICANT
CHANCE OF PRECIP WILL OCCUR ON THURSDAY WHEN ANOTHER SHORT WAVE
APPROACHES FROM THE WEST.

FOR TEMPS...GENERALLY WENT WITH A BLEND OF GUIDANCE NUMBER.

PRELIMINARY NUMBERS FOLLOW:
CHA   78  54  75  50 /  90  10   0   0
TYS   77  52  72  48 /  90  10   0   0
TRI   75  50  69  43 /  90  10   0   0
OQT   77  52  73  48 /  90  10   0   0

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

LCM

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EVENING FORECAST DISCUSSION
641 PM EDT SAT MAY 10 2003

QUICK UPDATE TO REMOVE MENTION OF TORNADO WATCH AND EVENING SHOWERS
AND THUNDERSTORMS.  ALSO TWEAKED SKY COVER TO READ INCREASING
CLOUDINESS.  NO OTHER CHANGES.

29

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AFTERNOON FORECAST DISCUSSION
248 PM EDT SAT MAY 10 2003

TORNADO WATCH REMAINS IN EFFECT UNTIL 7PM EDT FOR SWRN VA...AND WE
HAVE HAD SOME WEAK TSRA START TO DEVELOP THAT AREA INTO NE TIP OF TN
OVER PAST HALF HOUR.  THIS WAS THE AREA WHERE THE CAP (WARM TEMPS
ALOFT) WAS WEAKEST.  THIS ACTIVITY IS PUSHING JUST ABOUT DUE EAST...
BUT I WOULD NOT RULE OUT OUTFLOW BOUNDARIES HELPING TO DEVELOP SOME
MORE CONVECTION FURTHER SOUTH THIS EVENING.  THUS...ADDED SOME 20-30%
POPS FOR THIS EVENING...IN JUNCTION WITH THE EXPECTED SHRA/TSRA VERY
LATE TONIGHT AS COLD FRONT APPROACHES.  OTHERWISE...KEPT LIKELY POPS
AND SAME TIMING FOR SUNDAY SYSTEM AS PREVIOUS ZFP/GRIDS.  DID BREAK
UP CLOUDS JUST A BIT SOONER FROM WEST TO EAST BY SUNDAY AFTERNOON.

LATER PERIODS...DRYING AND SLIGHTLY COOLER MON/TUE THEN RAIN CHANCES
BACK FOR MID TO LATE WEEK.  DID NOT STRAY MUCH FROM SIMILAR MOS
TEMPS.  PRELIMINARY TEMPS/POPS FOLLOW:

.MRX...
NC...NONE.
TN...NONE.
VA...TORNADO WATCH FOR THIS AFTERNOON FOR ZONES VAC105...VAC167...
VAC169...VAC191...VAC195.

TORNADO WATCH FOR THIS AFTERNOON AND EVENING FOR ZONES VAC105...
VAC167...VAC169...VAC191...VAC195.

TG
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MORNING FORECAST DISCUSSION (UPDATE)
945 AM EDT SAT MAY 10 2003

ACTIVE WEATHER CONTINUES TO BE WELL NORTH OF THE FORECAST AREA THIS
MORNING...MAINLY OVER MID MISS AND OHIO VALLEYS.  12Z BNA/RNK AND
FORECAST SOUNDINGS SHOW STRONG INSTABILITY FOR THIS AFTERNOON...WITH
CAPES EASILY REACHING 2000 TO 3000 J/KG.  MODIFIED 12Z SOUNDINGS
MATCHED THE MESO-ETA FORECAST SOUNDINGS IN SHOWING THAT THE WARM
TEMPS ALOFT WILL ONLY PROVIDE A VERY WEAK CAP.  HOWEVER...LITTLE IF
ANY LOW LEVEL MOISTURE CONVERGENCE IS INDICATED FOR THIS AFTERNOON.
THUS...THE CURRENT 20-30% CHANCE POPS SHOULD BE SUFFICIENT.

REST OF FORECAST ALSO APPEARS TO BE ON TRACK...BUT I WILL NEED A
COSMETIC UPDATE TO REMOVE AFTERNOON WORDING ON POPS AND GUSTY WINDS.

TG

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-005-
006-008-120900-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
500 AM EDT SUN MAY 11 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST TENNESSEE...SOUTHWEST
VIRGINIA AND EXTREME SOUTHWEST NORTH CAROLINA.

.DAY ONE (TODAY)...

A COLD FRONT WILL MOVE THROUGH THE SOUTHERN APPALACHIAN REGION THIS
MORNING...BRINGING A SQUALL LINE WITH THE POSSIBILITY OF DAMAGING
WINDS...LARGE HAIL AND LOCALLY HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN (MONDAY THROUGH SATURDAY)...

THERE IS A SLIGHT CHANCE FOR SEVERE THUNDERSTORMS ON WEDNESDAY NIGHT
INTO THURSDAY...AS A LOW PRESSURE SYSTEM MOVES NEAR THE REGION. HEAVY
RAINFALL WILL ALSO BE A POSSIBILITY WEDNESDAY NIGHT INTO THURSDAY.

IN ADDITION...THERE IS A SLIGHT CHANCE FOR SEVERE THUNDERSTORMS ON
SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY...AND POSSIBLY AGAIN WEDNESDAY
NIGHT AND THURSDAY.

PLEASE STAY TUNED TO NOAA WEATHER RADIO OR VISIT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/MRX.

DMG