Severe Thunderstorm Warning 76, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
330 AM CST THU MAR 9 2000

LATEST SURFACE ANALYSIS SHOWS STATIONARY BOUNDARY JUST SOUTH OF PINE
BLUFF TO NORTH OF THE TN/MS BORDER. TEMPS RANGE FROM THE MID 60S TO
NEAR 70 SOUTH OF THIS BOUNDARY WITH DEWPOINTS IN THE LOWER TO MID
60S OVER MOST AREAS. 88D SHOWING SCATTERED SHOWER AND THUNDERSTORM
ACTIVITY ASSOCIATED WITH EXITING MID LEVEL SHORTWAVE.

MODELS DIFFER SOME AT THE UPPER LEVELS...BUT FORECAST SURFACE
FEATURES ARE PRETTY SIMILAR. AVN TENDS TO BE THE STRONGEST OF ALL
MODELS WITH THIS SYSTEM. TIMING OF FEATURES IS RELATIVELY THE SAME
WITH ALL MODELS. WEAK BOUNDARY TO THE NORTH WILL SLOWLY MOVE NORTH
OVER TIME AS A DEVELOPING SURFACE LOW OVER SOUTHEAST TEXAS BEGINS TO
MOVE EAST TODAY. SURFACE LOW IS EXPECTED TO BE SOMEWHERE BETWEEN
VICKSBURG AND GREENWOOD BY 06Z TONIGHT AND THE TRAILING COLD FRONT
ALONG THE MISSISSIPPI RIVER. MODELS ARE ALSO INDICATING THE
POSSIBILITY OF A SQUALL LINE DEVELOPING AHEAD OF THE COLD FRONTAL
BOUNDARY. BY 12Z SATURDAY THE FRONT SHOULD BE ORIENTED ALONG A
COLUMBUS TO JACKSON TO BROOKHAVEN LINE...AND SHOULD RAPIDLY MAKE ITS
WAY EAST OF THE STATE BY LATE AFTERNOON.

MODELS ARE INDICATING INSTABILITY ALONG AND SOUTH OF THE BOUNDARY IN
NORTHERN MS TODAY WITH LIS AROUND -2 AND CAPES RANGING FROM THE 1500
TO 2000 J/KG RANGE. THINK ANY CONVECTION THAT OCCURS WITH THIS
BOUNDARY TODAY WILL BE SCATTERED IN NATURE. WITH FRONT APPROACHING
THE REGION TONIGHT...WITH THE FORMATION OF A SQUALL LINE
...CONVECTION WILL BE MORE WIDESPREAD. LATE SATURDAY AFTERNOON...
CONDITIONS WILL BE IMPROVING AND COLD AIR ADVECTION WILL BEGIN TO
TAKE PLACE. A GOOD SHOT OF COLD AIR BEHIND THIS FRONT WILL LEND TO
OVERNIGHT MIN TEMPERATURES IN THE 30S ACROSS THE THE CWFA...WITH THE
POSSIBILITY OF PATCHY FROST IN THE NORTHERN ZONES.

OVERALL...WILL LEAN TO THE MORE CONSERVATIVE ETA/NGM SOLUTION THIS
PD. THINK THAT THE AVN TENDS TO SHIFT THE AXIS OF INSTABILITY
(ASSOCIATED WITH THE COLD FRONT AND/OR SQUALL LINE) TOO FAR EAST TOO
QUICKLY. MOS AND FAN GUIDANCE ARE PRETTY SIMILAR WITH THE TEMP
FORECASTS AND WILL TAKE AVERAGE. AS FAR AS POPS GO...WILL LEAN MORE
TO THE CONSERVATIVE MOS NUMBERS.

QPF DISCUSSION: MODEL QPF AMOUNTS STILL DIFFER...AVN TOO WET...BUT
THE ETA HAS COME MORE IN LINE THAN IN PREVIOUS RUNS. WILL TAKE THE
ETA COMPROMISE AND RAISE A BIT AND GO WITH ONE QUARTER TO ONE INCH
BASIN AVERAGES FOR THE 24 HOUR TIME FRAME. HIGHEST RAINFALL AMOUNTS
WILL FALL FROM 00Z TO 12Z SATURDAY.

IN THE EXTENDED...CURRENT EXTENDED LOOKS FINE AND WILL ONLY MAKE
COSMETIC CHANGES TO MESH WITH NEW ZONE GRO/UPINGS.

PRELIM NUMBERS...
JAN 077/055/058/032 3630
MEI 078/058/060/034 3550

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

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
110500-

AREA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
1043 AM CST FRI MAR 10 2000

A STATIONARY FRONT...EXTENDING FROM BASTROP LOUISIANA TO
GREENVILLE TO NORTH OF GREENWOOD MISSISSIPPI...WILL COMBINE
WITH A SERIES OF UPPER LEVEL DISTURBANCES MOVING ALONG IT TO PRODUCE
SCATTERED TO NUMEROUS THUNDERSTORMS THIS AFTERNOON AND EVENING. THE
BEST MOISTURE AND INSTABILITY WILL RESIDE OVER AREAS WEST OF A
CLEVELAND TO JACKSON TO BUDE MISSISSIPPI LINE AND WITH THE PROXIMITY
OF STRONG UPPER LEVEL JET STREAM...SOME STORMS MAY BECOME SEVERE WITH
LARGE HAIL AND DAMAGING WIND BEING THE MAIN THREATS.

AS THE MAIN UPPER LEVEL STORM NEARS THE AREA TONIGHT...A SQUALL
LINE OF THUNDERSTORMS WILL DEVELOP AND APPROACH THE MISSISSIPPI
RIVER AFTER MIDNIGHT. THE LINE OF STORMS WILL CONTINUE EAST
OVERNIGHT AND INTO SATURDAY MORNING...MOVING INTO EASTERN SECTIONS
BY NOON SATURDAY. ONCE AGAIN...WITH THE PROXIMITY OF A STRONG UPPER
LEVEL JET STREAM...SOME STORMS MAY BE SEVERE WITH LARGE HAIL AND
DAMAGING WIND.

ACTIVATION OF STORM SPOTTERS...EMERGENCY MANAGEMENT PERSONNEL AND HAM
RADIO OPERATORS MAY BE NECESSARY BY TONIGHT.

FOR MORE INFORMATION...PLEASE VISIT OUR NEW INTERNET WEB SITE AT
HTTP://WWW.SRH.NOAA.GOV/JAN