Severe Thunderstorm Warning 42, 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

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-005-
006-008-251400-

AREA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
413 AM EDT THU MAY 25 2000

...SEVERE THUNDERSTORM WATCH IN EFFECT FOR AREAS SOUTH OF
INTERSTATE 40 UNTIL 10 AM EDT (9 AM CDT)...

THUNDERSTORMS WILL MOVE THROUGH THE SOUTHWEST VIRGINIA...EAST
TENNESSEE AND EXTREME SOUTHWEST NORTH CAROLINA THIS MORNING. THERE
IS A CHANCE THAT SOME STORMS SOUTH OF INTERSTATE 40 COULD BECOME
SEVERE THIS MORNING. THERE WILL BE SCATTERED THUNDERSTORMS THIS
AFTERNOON AND TONIGHT...BUT NONE OF THESE STORMS ARE EXPECT TO BECOME
SEVERE.

A WEAK COLD FRONT WILL MOVE THROUGH THE REGION TODAY AND THEN
BECOMING STATIONARY JUST SOUTH OF TENNESSEE TONIGHT. THIS FRONT
WILL BRING A CHANCE OF THUNDERSTORMS THROUGHOUT TODAY AND TONIGHT. AN
UPPER LEVEL DISTURBANCE WILL MOVE ALONG THE FRONT THIS MORNING AND
BRING THE AREA THE BEST CHANCE OF THUNDERSTORMS DURING THE MORNING.
SOME OF THESE STORMS DURING THE MORNING COULD BE SEVERE SOUTH OF
INTERSTATE 40. SEVERE STORMS EXTENDED ACROSS MIDDLE TENNESSEE AND
WERE MOVING EAST CLOSE TO 40 MPH. THESE STORMS WILL AFFECT THE
SOUTHERN AND CENTRAL VALLEY REGIONS BETWEEN 500 AM EDT (400 AM CDT)
AND 800 AM EDT (700 AM CDT).

SCATTERED THUNDERSTORM ARE EXPECTED TO DEVELOP LATER THIS AFTERNOON
AND TONIGHT NEAR THE COLD FRONT...BUT NONE OF THESE STORMS ARE
EXPECTED TO BE SEVERE.

THE THUNDERSTORMS THIS MORNING WILL HAVE THE POTENTIAL TO PRODUCE
HEAVY RAINFALL AND POSSIBLY LOCALIZED FLASH FLOODING. RAINFALL
AMOUNTS WILL EXCEED ONE INCH IN MANY LOCATIONS...WITH LOCALIZED
AREAS RECEIVING AROUND THREE INCHES OF RAIN.

THE THUNDERSTORMS TODAY WILL MOVE EAST OR SOUTHEAST AT 30 TO 35 MPH.
SOUTH OF INTERSTATE 40 THIS MORNING...THE STORMS WILL BE CAPABLE OF
PRODUCING WIND GUSTS UP TO 70 MPH...HAIL THREE QUARTERS OF AN INCH
IN DIAMETER...AND POSSIBLY AN ISOLATED TORNADO. ALL OTHER
THUNDERSTORMS TODAY AND TONIGHT WILL BE CAPABLE OF PRODUCING WIND
GUSTS UP TO 45 MPH AND PEA SIZE HAIL.

SKYWARN SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL MAY NEED TO BE
ACTIVATED TONIGHT. STAY TUNED TO NOAA WEATHER RADIO...LOCAL
TELEVISION AND RADIO STATIONS...OR CABLE TELEVISION FOR THE LATEST
STATEMENTS ON THE POTENTIAL OF SEVERE WEATHER.