Severe Thunderstorm Warning 664, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
210 PM CST WED NOV 8 2000

WILL BE BRIEF. MODELS ARE TRENDING FARTHER NORTHWEST WITH THE TRACK
OF THE SURFACE LOW AS WELL AS DEEPER WITH THE CENTRAL PRESSURE. THIS
PUTS OUR CWFA FIRMLY INTO THE WARM SECTOR RATHER THAN HAVING THE
WARM FRONT LINGERING NEARBY AS WAS THOUGHT YESTERDAY. MODELS ALSO
TRENDING STRONGLY FASTER WITH THE EASTWARD PROGRESSION OF THE COLD
FRONT...WHIPPING IT THROUGH OUR CWFA BETWEEN MIDNIGHT AND SUNRISE.
THIS IS ABOUT SIX HOURS FASTER THAN THE MODEL RUNS YESTERDAY
INDICATED. STILL STRONG DYNAMIC SUPPORT OVERNIGHT FOR SEVERE WEATHER
AHEAD OF THE FRONT...PARTICULARLY ALONG I-59 CORRIDOR. COULD BE A
ONE-TWO PUNCH OF WARM SECTOR SUPERCELLS FOLLOWED BY A PREFRONTAL
SQUALL LINE. WILL HIT SEVERE WEATHER IN ALL ZONES DUE TO POTENTIAL
OF WIDESPREAD DAMAGING WINDS WITH SQUALL LINE. HEAVY RAIN BECOMING A
LESSER THREAT WITH TIME DUE TO FASTER MOTION OF FRONT AND LESS
COVERAGE THIS AFTERNOON THAN PREVIOUSLY EXPECTED.

UPDATE: NEW MESO ETA OUTPUT COMING IN AND TRENDING EVEN FASTER THAN
12Z RUNS. WILL INTEGRATE THIS WITH EVERYTHING ELSE.

TEMPS WILL FALL QUICKLY BEHIND THE SQUALL LINE/COLD FRONT AS WINDS
SHIFT TO WESTERLY AND LOW LEVEL THICKNESSES TUMBLE. LOW LEVEL WINDS
WILL VEER TO NORTHERLY BY EVENING AND DIMINISH RAPIDLY...ALLOWING
TEMPS TO TUMBLE LOWER THAN PREVIOUSLY FORECAST UNLESS COLD ADVECTION
STRATUS DEVELOPS. WILL FURTHER INVESTIGATE THIS POSSIBILITY AS TIME
ALLOWS.

24 HOUR QPF DISCUSSION: MOISTURE STREAMING INTO REGION IN INCREASING
LOW LEVEL FLOW. MODELS MAINTAIN PRECIPITABLE WATER FROM 1.5 TO 2
INCHES THROUGH THE EVENING...INCREASING INTO NRN SECTIONS IN THE
WAKE OF THE WARM FRONT. NCEP/MODEL TRENDS PLACE HIGHEST AMOUNTS TO
THE SOUTH AND EAST THROUGH 12Z. THIS LOOKS REASONABLE SOUTH WHERE
INSTABILITIES BEST AND CONVECTION TO INITIATE FIRST. NO BIG
ARGUMENTS WITH THE MORE ERN PLACEMENT DUE TO THE EFFECTS OF
ONGOING CONVECTION SOUTHEAST MISSISSIPPI COMBINED WITH CONVECTION
WITH THE APPROACHING COLD FRONT. AREAL AMOUNTS TOTALLING 0.75 TO
1.5 INCH THROUGH 12Z THU EXPECTED...WITH LOCALLY HIGHER AMOUNTS.

OPERATIONAL MRF AND NOGAPS/NOGPAS ENSEMBLES/NCEP ENSEMBLES ALL SHOW
DRY THROUGH MONDAY AND WILL RUN WITH IT.

PRELIMINARY NUMBERS...SUBJECT TO CHANGE...
JAN 052/054 037/063 +20
MEI 056/058 037/063 +40

.JAN...
AR...NONE.
LA...NONE.
MS...NONE.
06

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
091200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
100 PM CST WED 8 2000

...THUNDERSTORMS...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT IN EASTERN LOUISIANA AND MISSISSIPPI...ESPECIALLY SOUTH OF
INTERSTATE 20.  THE MAIN THREAT THIS AFTERNOON WILL BE FROM HAIL AND
DAMAGING STRAIGHT-LINE WINDS.  ISOLATED SUPERCELL STORMS MAY ALSO
PRODUCE BRIEF TORNADOES...ESPECIALLY IN MISSISSIPPI.  SPOTTER
ACTIVATION MAY OCCUR AT ANYTIME THROUGH THIS EVENING.

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS AFTERNOON AND
EVENING ALONG AND SOUTH OF A VICKSBURG TO STARKVILLE LINE.  MOST OF
THESE STORMS WILL REMAIN BELOW SEVERE LIMITS.  HOWEVER...VERTICAL
WIND PROFILES SUGGEST THAT A FEW STORMS MAY PRODUCE BRIEF
TORNADOES...ESPECIALLY NEAR THE VICINITY OF THE WARM FRONT.  IN
ADDITION...A STRONG COLD FRONT IN EAST TEXAS WILL SWEEP THROUGH
LOUISIANA AND MISSISSIPPI LATE TONIGHT.  A LINE OF STRONG TO SEVERE
THUNDERSTORMS WILL DEVELOP AHEAD OF THE FRONT...WITH THE MAIN THREAT
BEING FROM STRAIGHT-LINE WINDS.

...FLOODING...
WHILE NO WIDE-SCALE FLOODING OR FLASH FLOODING IS EXPECTED...STORMS
THAT DEVELOP GENERALLY SOUTH OF INTERSTATE 20 MAY PRODUCE VERY HEAVY
LOCALIZED RAINS THROUGH TONIGHT. IN THE MOISTURE-LADEN AIRMASS...
COPIOUS AMOUNTS OF RAINFALL COULD DEVELOP. POTENTIAL RAIN TOTALS BY
THURSDAY MORNING COULD RANGE FROM NEAR ONE INCH IN SOUTHEAST
MISSISSIPPI...TO OVER THREE INCHES OVER PARTS OF NORTHEAST
LOUISIANA...SOUTHEAST ARKANSAS...AND WEST MISSISSIPPI.

FOR MORE INFORMATION PLEASE VISIT OUR WEB SITE AT
WWW.SRH.NOAA.GOV/JAN. THIS INCLUDES A GRAPHICAL HAZARDOUS WEATHER
OUTLOOK.