Damaging Wind in Tennessee, July 21, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
250 PM EDT SUN JUL 21 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 SUN JUL 21 2002

CURRENT RADARS SHOWING ISOLATED TSTORMS ALONG THE SOUTHERN CUMBERLAND
PLATEAU THIS AFTERNOON...WITH A MOIST AND MODERATELY UNSTABLE AIRMASS
IN PLACE. THE UPPER HIGH ACROSS THE AREA TODAY...IS PROGGED TO WEAKEN
TOMORROW...WHICH SHOULD ALLOW FOR A SLIGHTLY BETTER COVERAGE OF
AFTERNOON CONVECTION. A COLD FRONT IS THEN EXPECTED TO QUICKLY MOVE
TOWARD THE FORECAST AREA BY TUESDAY NIGHT. WILL BASICALLY CONTINUE
WITH THE PREVIOUS FORECAST OF INCREASING POPS FOR TUESDAY INTO
TUESDAY NIGHT. LATEST AVN MODEL RUN INDICATES THAT THIS FRONT WILL BE
ACROSS THE AREA ON WEDNESDAY...SO WILL RAISE WEDNESDAY POPS TO 50
PERCENT.

IN THE EXTENDED...THIS COLD FRONT IS PROGGED TO BECOME QUASI-
STATIONARY BY THURSDAY ALONG THE EASTERN FOOTHILLS OF THE SOUTHERN
APPALACHIANS. THUS...WILL CONTINUE WITH A CHANCE OF TSTORMS ON
THURSDAY...WITH A SLIGHT CHANCE ON FRIDAY AND SATURDAY WITH AN
UNSTABLE AIRMASS STILL IN PLACE. THINK THAT PRECIP CHANCES THURSDAY
THROUGH SATURDAY WILL BE A LITTLE BETTER IN THE MOUNTAINS.

AS FOR TEMPS...ALL THREE SETS OF GUIDANCE NUMBERS ARE IN GENERAL
AGREEMENT WITH MINS THROUGH THE FORECAST PERIOD...WHILE THE AVN
MAXES SEEMS A LITTLE TOO COOL.

THE FOLLOWING NUMBERS ARE PRELIMINARY AND FOR COORDINATION ONLY:

CHA   72  94  72  93 /  20  30  30  40
TYS   70  91  70  90 /  10  30  30  40
TRI   66  89  67  87 /  10  30  30  40
OQT   70  91  70  90 /  10  30  30  40

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

DMG

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MIDDAY FORECAST DISCUSSION (UPDATE)
1020 AM EDT SUN JUL 21 2002

PLENTY OF S/B MOISTURE AROUND FOR TODAY...AS EVIDENCED WITH
WIDESPREAD FOG EARLIER THIS MORNING (DENSE IN SOME NORTHERN/CENTRAL
AREAS). EARLY VIS AND IR SATELLITE PIX SHOW CLEAR SKIES ABOVE THE FOG
LAYER...AND THE LATEST MODEL DATA CONTINUE TO SHOW DRIER AIR WORKING
TOWARD THE SURFACE THROUGH SINKING MOTIONS. NEVERTHELESS...CU RULE
WITH AFTERNOON HEATING IS ENOUGH FOR A PARTLY CLOUDY SKY TO DEVELOP.

AS FOR POP/S...A FEW TSTORMS MAY DEVELOP LATE (BEST CHANCE IN THE
SOUTHERN MOUNTAINS)...AND WILL NOT UPDATE THE FORECAST TO MINIMIZE
THE ISOLATED COVERAGE CURRENTLY GOING. VERY WARM TEMPERATURES
LOOK ON TRACK.

NO FORECAST UPDATE PLANNED.

DM

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MORNING FORECAST DISCUSSION
300 AM EDT SUN JUL 21 2002

GENERALLY BENIGN WEATHER IN STORE THROUGH THE NEAR TERM AS RIDGING
SURFACE AND ALOFT BUILDS INTO THE SOUTHERN APPALACHIAN REGION.
HIGHER 500 MB HEIGHTS IMPLY A RETURN TO ABOVE CLIMATOLOGY TEMPS
THROUGH EARLY WEEK. THE UPPER RIDGE WILL BE SHUNTED BACK TO THE WEST
AS A NORTHERN STREAM SHORT WAVE DIGS INTO THE GREAT LAKES REGION BY
EARLY TUESDAY. THIS WILL RESULT IN AN INCREASE IN MOISTURE AT ALL
LEVELS. LACK OF ANY SPECIFIC FOCUSING MECHANISM MONDAY AFTERNOON
SUGGESTS THAT ONLY SCATTERED CONVECTION IS IN THE OFFING. AN
ASSOCIATED SURFACE FRONT WILL APPROACH THE AREA LATE TUESDAY
PROVIDING A FOCUS FOR MORE ORGANIZED CONVECTION.

MOS TEMP GUIDANCE GENERALLY CLOSE AND APPEARS REASONABLE. TENDED TO
USE A BLEND WHERE DIFFERENCES OCCURRED.

PRELIMINARY CCF FOLLOW:
CHA   94  72  93  72 /  20  10  30  20
TYS   91  70  90  70 /  20  10  30  20
TRI   90  66  89  67 /  20  10  30  20
OQT   92  71  91  71 /  20  10  30  20

LCM

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EVENING FORECAST DISCUSSION (UPDATE)
920 PM EDT SAT JUL 20 2002

ISOLATED SHOWERS AND THUNDERSTORMS MOVING SOUTH ACROSS EXTREME
SOUTHEAST TN...WILL BE SOUTH OF CWA BY UPDATE TIME.  WILL UPDATE TO
TAKE POPS OUT OF ZONES FOR THE REST OF TONIGHT.  MAY SEE SOME PATCHY
FOG IN AREAS THAT RECEIVED RAIN TODAY...BUT SHOULD NOT BE BAD ENOUGH
TO MENTION IN ZONES.  TEMPERATURES LOOK GOOD.

GH