Severe Thunderstorm Warning 40, NWS Morristown, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
252 AM EDT THU MAY 25 2000

...MAIN CHALLENGE WHEN AND WHERE WILL PRECIP BE TODAY...

ALL MODELS ARE HAVING TROUBLE PICKING UP THE SURFACE BOUNDARY AND
CURRENT MCS WITH AN EMBEDDED MVC (MESOSCALE VORTICITY CENTER).
SURROUNDING RADARS SHOWING MCS TO MOVE EAST...BUT TRAINING OVER THE
SAME AREAS...AND PRODUCING HEAVY RAINS...AND SEVERE WEATHER. AS THE
SHOWERS AND THUNDERSTORMS MOVE EAST...COULD SEE AN ISOLATED SEVERE
THUNDERSTORM...BUT LOOKS AS THOUGH MAIN THREAT WILL BE HEAVY RAINS
AND FLOODING.

AGREE WITH HEAD QUARTERS THAT AVN HAS THE BEST HANDLE SO HAVE GONE
WITH THAT SOLUTION THIS FORECAST.

CURRENTLY SURFACE BOUNDARY LOCATED ALONG AND SOUTH OF I-40...SO
CURRENT CONVECTION SHOULD FOLLOW THAT LINE THROUGH THIS MORNING.
GIVEN THE NORMAL DECAY STAGE OF THE MCSS OF THE PAST COUPLE OF
DAYS...WILL BE INTERESTING TO SEE HOW LONG PRECIP LASTS AFTER 12Z.
RADAR MOSAIC SHOWS A NICE COMMA HEAD SHAPE TO THE PRECIPITATION.
WITH THIS IN MIND HAVE GONE CATEGORICAL ALONG AND SOUTH OF I-40
WITH CHANCE POPS ELSEWHERE.  BEST UPPER LEVEL DYNAMICS SLOWLY MOVING
EAST AND THIS TREND IS SEEN IN THE FASTER MOVEMENT TO THE EAST OF
THE THUNDERSTORMS.

AS FOR THIS AFTERNOON...WITH THE SUBSIDENCE BEHIND THE MCS AND THE
FACT THAT A LARGE OUTFLOW BOUNDARY SHOULD BE WELL SOUTH OF THE
AREA...MOST OF THE CONVECTION AND PRECIPITATION SHOULD END BY NOON...
AND WILL LET THE DAY SHIFT UPDATE FORECAST IF NEED BE...AND WILL NOT
USE TIMING OF PRECIP IN ZONES.  AS FOR TEMPERATURES HAVE GONE NEAR
FWC/FAN NUMBERS.

FOR TONIGHT...MODELS INDICATE A CHANCE FOR MORE SHOWERS AND
THUNDERSTORMS TO DEVELOP...BUT WITH THE BEST LOW-LEVEL JET AND
UPPER LEVEL DYNAMICS SHIFT TO THE WEST OVER THE PLAINS...AND THE FACT
THAT THE RIDGE BUILDS INTO THE COUNTY WARNING AREA...WILL ONLY GO
WITH CHANCE POPS OVERNIGHT...AND KEEP TEMPS NEAR FWC/FAN VALUES.

FOR FRIDAY...ONCE AGAIN THE ATMOSPHERE REMAINS UNSTABLE...BUT WITH
NO SURFACE BOUNDARIES...AND NO REAL UPPER LEVEL SUPPORT...HAVE KEPT
SLIGHT CHANCE POPS IN.  AVN/ETA SHOW THE WARM FRONT FINALLY MOVING
NORTH OF THE FORECAST AREA AS THE RIDGE BUILDS IN...AND BEST LOW-
LEVEL AND UPPER LEVEL SUPPORT REMAINS OVER THE PLAINS.  AS FOR
TEMPERATURES HAVE GONE NEAR FWC/FAN NUMBERS.

FCSTID = 2
CHA   84  65  85  68 / 100  30  30  30
TYS   80  60  82  64 /  80  30  30  30
TRI   79  58  80  61 /  40  30  30  30
OQT   81  61  83  65 /  80  30  30  30

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

PDK

TNZ012>014-035>037-067>069-071-072-250510-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
1240 AM EDT WED MAY 24 2000

...THE TORNADO WATCH HAS BEEN CANCELED FOR PORTIONS OF EAST TENNESSEE AND
THE NORTHERN CUMBERLAND PLATEAU...

THE TORNADO WATCH HAS BEEN CANCELED FOR PORTIONS OF EAST TENNESSEE.
HOWEVER...SEVERE THUNDERSTORMS CONTINUE TO MOVE ACROSS MIDDLE
TENNESSEE AND ADDITIONAL SEVERE STORMS WERE LOCATED NEAR THE
MISSISSIPPI RIVER. THESE STORMS WILL CONTINUE TO MOVE EAST 25 TO 30
TO MPH AND MAY MOVE INTO EAST TENNESSEE LATER TONIGHT.

THERE IS STILL THE THREAT FOR SEVERE STORMS FOR EAST TENNESSEE LATER
TONIGHT. THE THUNDERSTORMS WILL PRODUCE LOCALLY HEAVY RAINFALL.
WATCH FOR HIGH WATER ALONG CREEKS AND RIVERS...AND PONDING ON
ROADS.  ANY STORMS THAT BECOME SEVERE MAY PRODUCE WIND GUSTS UP TO
70 MPH...AND HAIL UP TO ONE AND THREE QUARTERS INCH IN DIAMETER...OR
ABOUT THE SIZE OF GOLF BALLS.  AN ISOLATED TORNADO IS ALSO STILL
POSSIBLE.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL TELEVISION AND RADIO
STATIONS...OR CABLE TELEVISION FOR THE LATEST STATEMENTS ON THE
POTENTIAL OF SEVERE WEATHER.

RBP