Severe Thunderstorm Warning 83, NWS Jackson, MS

AREA FORECAST DISCUSSION...CORRECTION TO PRELIM NUMBERS
NATIONAL WEATHER SERVICE JACKSON MS
245 AM CST SUN FEB 25 2001

ANOTHER EVENT WINDING DOWN FOR THE FORECAST AREA AS DEEPENING UPPER
LOW HEADS FOR THE GREAT LAKES....BEING SHUNTED NORTH BY SUBTROPICAL
HIGH CENTERED OVER CARIBBEAN/CENTRAL AMERICA. SYSTEM DIGGING INTO
THE SOUTHWESTERN CONUS WITH ANOTHER DIVING INTO SOUTH-CENTRAL
CANADA. SURFACE LOW OF STEEL DEEPENING SYSTEM HEADING INTO UPPER
MISSISSIPPI RIVER VALLEY(898MB MSL PRESSURE ON MIDNIGHT SURFACE
ANALYSIS AND STILL DEEPENING). SURFACE FRONT ASSOCIATED WITH CENTRAL
CONUS SYSTEM MOVING THROUGH CENTRAL MO/AR INTO EASTERN TX ON 06Z
ANALYSIS. CURRENT SQUALL LINE MOVING OVER THE FA STARTING TO LOSE
STEAM AS SURFACE GUST FRONT IS BECOMING DISASSOCIATED WITH MAIN TSRA
COMPLEX. ANOTHER SQUALL LINE AFFECTING SOUTHEASTERN SECTIONS OF MS
HAS MOVED INTO AL...WITH LOW LEVEL WINDS TAPERING OFF OVER
SOUTHEASTERN SECTIONS OF STATE.

SHORTRANGE MODELS CONTINUE CENTRAL CONUS LOW DEEPENING(AT LEAST
THROUGH SUNRISE) AS IT CLIMBS NORTH. GOOD LOW LEVEL FLOW CONTINUES
PULLING NORTH WITH SURFACE LOW...SO WINDS CONTINUE TO SLACK OFF
FROM WINDY CONDITIONS TODAY. LOW LEVEL HIGH PRESSURE OVER SOUTHERN
US ROCKIES PROGGED TO MOVE EAST TO OVER CENTRAL MISS RIVER VALLEY BY
EARLY MONDAY MORN...THEN WEAKEN AS IT MOVES NORTH INTO MID WEEK AS
SOUTHWESTERN LOW MEANDERS ITS WAY EAST OVER THE DESERT SOUTHWEST...
AND LONG CANADIAN SHORTWAVE TROUGH DIGS SOUTH INTO THE NORTHERN US
ROCKIES/PLAINS STATES. RESULT IS A RETURN TO EASTERLY FLOW LATER
MONDAY INTO MONDAY NIGHT...SOUTHERLY FLOW OVER SOUTHERN PLAINS BY
MON NIGHT. WITH SURFACE BOUNDARY PUSHING THROUGH LOWER MISS RIVER
VALLEY TONIGHT BEFORE STALLING ALONG GULF COAST BY EARLY MONDAY.
CONCERN IS PRESENT FOR SOUTHEASTERN SECTIONS OF STATE IF BOUNDARY
HOLDS CURRENT SPEED(ETA/NGM/AVN PRETTY CLOSE WITH POSITION BY
F36/MON MORN)...AND ENOUGH SUN PEEKS THROUGH TO DESTABILIZE THE
AIRMASS AHEAD OF FRONT. ETA ADVERTISING CAPES OVER 2000 J/KG. HAVE A
FEELING THAT ANOTHER ROUND OF WATCHES WILL BE ISSUED FOR THIS AREA
THIS AFTERNOON. MODEL SOUNDINGS FOR THE AREA SHOWING A WEAK...LINEAR
WIND PROFILE WITH GOOD MID LEVEL DRY AIR...SO MAIN THREAT LOOKS TO
BE HIGH WINDS...SOME LARGE HAIL...MAYBE AN ISOLATED TORNADO. WILL
LIKELY LEAVE IN SEVERE WORDING SOUTHEASTERN SECTIONS(SPC HAS A
SLIGHT RISK FOR FA SOUTH OF A KHEZ TO KMEI LINE ON 05Z CONVECTIVE
OUTLOOK). SEVERE RISK IS HIGHLY DEPENDENT UPON AMOUNT OF HEATING
RECEIVED DURING THE DAY TODAY. WITH AFTERNOON TEMPS IN THE MID 70S
AND DEW POINTS AROUND 70...NOT MUCH ADDITIONAL HEATING WILL BE
NEEDED. AM GOING WITH ROUGH FRONTAL POSITION OF STARTING TO MOVE
INTO WESTERN SECTIONS OF FA AT BEGINNING OF TODAY/S FORECAST
PERIOD...QUITMAN TO MCCOMB LINE BY BEGINNING OF TONIGHT/S FORECAST
PERIOD...THEN ALMOST TO COAST BY BEGINNING OF MONDAY NIGHT/S
FORECAST PERIOD AS FRONT LOSES STEAM.

FOR THE FORECAST...AM GOING TO PROBABLY TWEAK TO MOS NUMBERS TODAY
FOR COOLER...BUT DRIER AIR MOVING IN BEHIND BOUNDARY NORTHWESTERN
SECTIONS AND WARM...MUGGY CONDITIONS SOUTHEAST. POPS WILL TAPER FROM
ISOLATED MORNING SHOWERS NORTHWEST TO LIKELY SOUTHEAST. TONIGHT...
WILL LIKELY GO A BIT ABOVE MOS TEMPS AND POPS SOUTHEAST...NEAR MOS
TEMPS NORTHWEST. FOR MONDAY...BEST POPS LOOK TO BE SOUTHEAST
AHEAD/NEAR FRONT...SOUTHERN SECTIONS MONDAY NIGHT(USING MAV NUMBERS
AS A START). TEMPS...WILL LIKELY USE MAV NUMBERS AS A START..THEN
TWEAK FROM THERE.

QPF DISCUSSION...HPS AMOUNTS AND PLACEMENT LOOK GOOD FOR 12Z SUN
THROUGH 12Z MON.

IN THE EXTENDED...WITH EXTENSION OF ETA/NGM INTO EXTENDED...ALONG
WITH LOOK AT AVN...ANOTHER EVENT LOOKS TO BE IN THE WORKS FOR
TUESDAY AS SOUTHERLY FLOW PUSHES COASTAL BOUNDARY NORTH AND NORTHERN
AND SOUTHWESTERN CONUS SHORTWAVES MOVE SOUTH AND EAST...RESPECTIVELY.

PRELIMINARY NUMBERS...
JAN 071/045 065/049 4135
MEI 073/045 066/050 5135

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

16