Severe Thunderstorm Warning 36, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
300 PM CST SUN FEB 13 2000

FROM THE CURRENT RADAR AND SATELLITE TRENDS STILL PREFER THE ETA AS
THE MODEL OF CHOICE TODAY. BOTH THE ETA AND AVN PICKED UP ON THE
STRONG SHORTWAVE THAT MOVED AROSS TEXAS THIS MORNING...BUT STILL
FEEL THE AVN IS TOO FAST WITH THE SPEED AND DEEPENING OF THE SURFACE
LOW.

CURRENTLY STRONG/SEVERE THUNDERSTORMS ARE DEVELOPING FROM WEST
TENNESSEE BACK THROUGH SOUTHWEST LOUISIANA. THE STORMS ARE RAPIDLY
MOVING TO THE NORTHEAST. PARAMETERS FROM THE MID DAY SOUNDINGS SHOW
LAPSE RATES STILL STEEP...ON THE ORDER OF 7-7.5 C/KM...SWEAT INDICES
OF 450...WITH CAPES AROUND 1000 J/KG AND LIS OF -3 TO -5. A LOOK AT
CURRENT READINGS ACROSS THE FORECAST AREA SHOWS LIS OF -6 TO -8
OVER SOUTH ARKANSAS AND NORTHEAST LOUISIANA WITH DECENT PRESSURE
FALLS ACROSS THE CWFA. FROM MODEL TIMING AND CURRENT TRENDS MOST OF
THE ACTIVITY SHOULD BE EAST OF THE AREA BEFORE MIDNIGHT.

TIME SECTIONS SHOW DRIER AIR FILTERING IN FROM THE NORTHWEST LATE
TONIGHT. BY MONDAY MORNING...SURFACE COLD FRONT SHOULD BE ACROSS THE
EXTREME SOUTHEAST PORTION OF THE STATE...WITH HIGH PRESSURE
SETTING UP OVER THE STATE DURING THE DAY MONDAY. HIGH PRESSURE
CENTER SHOULD BE TO THE NORTHEAST BY EARLY TUESDAY. LOW LEVEL FLOW
BECOMES SOUTHERLY AGAIN ON TUESDAY...BUT STRONG RIDGE SHOULD KEEP
CONDITIONS DRY MONDAY THROUGH TUESDAY...AS A WARMING TREND ENSUES.

FOR THE FIRST PERIOD WILL GO ABOVE MOS WITH AS FAR AS POPS ARE
CONCERNED. NOT MUCH CHANGE FROM TEMPS...WILL TAKE AN AVERAGE AND MAY
VARY AROUND.

QPF DISCUSSION: SWIFT-MOVING SYSTEM LIMITS POTENTIAL FOR WIDESPREAD
...EFFICIENT HEAVY RAINFALL DEVELOPMENT. EXPECT LOCALLY HEAVIER
AMOUNTS IN STRONGER STORMS...MAINLY OVER NORTHERN COUNTIES. WILL GO
ALONG WITH NCEPS TRENDS FOR TIMING. EXPECT EVENT IS OVER AROUND 06Z
MOST AREAS EXCEPT SLIGHTLY LATER OVER EASTERN ZONES (11Z). LIGHTER
AMOUNTS THIS RUN OF MODELS ARE PREFERRED AND ACCEPTABLE. WILL GO WITH
AMOUNTS AROUND ONE QUARTER INCH OVER NORTH AND ONE TENTH TO ONE
QUARTER OTHERWISE.

PRELIM NUMBERS:
JAN 048/064 040/074 500
MEI 052/064 040/071 700

.JAN...
MS...NONE.
AR...NONE.
LA...NONE.

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
140400-

AREA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
1000 AM CST SUN FEB 13 2000

...SEVERE WEATHER IS EXPECTED ACROSS THE REGION THIS AFTERNOON AND
EVENING...

SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER THE AREA TODAY...AHEAD
OF A STRENGTHENING STORM SYSTEM MOVING FROM THE SOUTHERN PLAINS
STATES. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL MOVE RAPIDLY
EAST INTO THE LOWER MISSISSIPPI RIVER VALLEY THIS AFTERNOON AND
USHER IN COLDER AIR ALOFT. AT THE SAME TIME...A WARM FRONT WILL
SLIDE NORTH ACROSS ARKANSAS AND NORTH MISSISSIPPI INTO THE TENNESSEE
RIVER VALLEY.

THIS MORNING'S WIND PROFILES INDICATE SIGNIFICANT WIND SHEAR IS
DEVELOPING OVER THE REGION. STRONG LOW LEVEL SOUTHERLY FLOW HAS
CONTINUED TO PUMP MOISTURE FROM THE GULF OF MEXICO OVER THE REGION.
AT THE SAME TIME...WINDS AT THE MID AND UPPER LEVELS HAVE REMAINED
MORE WESTERLY. THIS TYPE OF WIND SHEAR WILL INCREASE THE POTENTIAL
FOR STRONG THUNDERSTORM DEVELOPMENT. WITH WARM...UNSTABLE AIR
ALREADY OVER THE REGION...ANY INSOLATION THROUGH BREAKS IN THE
CLOUDS WILL FURTHER FUEL STORM DEVELOPMENT. THEREFORE...THE MOST
LIKELY TIME FOR SEVERE WEATHER WILL BE FROM THIS AFTERNOON THROUGH
THE MID EVENING HOURS.

THE BEST POTENTIAL OF SEVERE WEATHER WILL BE ALONG AND NORTH OF A
RAYVILLE...LOUISIANA TO VICKSBURG TO JACKSON TO MERIDIAN LINE WHERE
SEVERE THUNDERSTORMS...DAMAGING WINDS...LARGE HAIL AND POSSIBLE
TORNADOES CAN BE EXPECTED. SOUTH OF THIS LINE...RESIDENTS OF
NORTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI SHOULD STILL BE ALERT
TO THIS WEATHER SITUATION...SINCE THERE IS A SLIGHT RISK OF SEVERE
THUNDERSTORMS...DAMAGING WINDS...AND LARGE HAIL OVER THAT AREA.

THERE IS THE POTENTIAL FOR EXTREMELY DANGEROUS WEATHER DEVELOPMENT.
BE SURE TO MONITOR THE LOCAL NEWS MEDIA...CABLE TELEVISION STATIONS
AND NOAA WEATHER RADIO FOR MORE UPDATES ON THIS DEVELOPING SEVERE
WEATHER SITUATION.

ACTIVATION OF STORM SPOTTERS...EMERGENCY MANAGEMENT PERSONNEL AND
HAM RADIO OPERATORS WILL LIKELY BE REQUIRED THIS AFTERNOON AND
TONIGHT.

FOR MORE INFORMATION...PLEASE VISIT OUR INTERNET WEB SITE AT
HTTP"://WWW.JANNWS.STATE.MS.US    /IN LOWER-CASE LETTERS/