Severe Thunderstorm Warning 85, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
150 PM CST TUE FEB 27 2001

WHISKEY ECHO TANGO.

ETA...AVN...AND NOGAPS ARE IN PRETTY GOOD AGREEMENT WITH WHAT
APPEARS TO BE AN UNFOLDING HEAVY RAIN AND FLOODING EVENT. A STEADY
PROGRESSION OF WEAK SHORTWAVES IN THE SOUTHERN STREAM WILL ZIP
ACROSS OUR CWFA THROUGH 12Z WEDNESDAY...THEN AFTER A SHORT
BREAK...ANOTHER STRONGER SHORTWAVE WILL PASS THROUGH THURSDAY NIGHT.
PLENTY OF MOISTURE WILL BE AVAILABLE THROUGH THE WEEK...WITH
PRECIPITABLE WATER VALUES AROUND AN INCH AND A HALF. ADDING TO THE
DELUGE WILL BE A SURFACE LOW DEVELOPING IN THE GULF SATURDAY MORNING
/PER AVN/ WHICH TRACKS INTO THE FL PANHANDLE BY SUNDAY MORNING.
STRONG WARM ADVECTION AND ISENTROPIC LIFT WITH THIS SYSTEM...PLUS
THE HIGH PRECIPITABLE WATER VALUES STILL FORECAST OVER THE DEEP
SOUTH...WOULD MEAN HEAVY RAIN ON ALREADY-SATURATED GROUND. ANYONE
WHO LIVES IN A RIVER FLOODPLAIN OR IN A POORLY DRAINED LOW-LYING
AREA SHOULD STAY ABREAST OF THE WEATHER THIS WEEK.

RAIN COOLED AIR FROM THE DELTA REGION IS HELPING TO PUSH THE FRONT
SOUTHWARD TODAY...AND THE MODELS HAVE NOT HANDLED THIS VERY
WELL...SO THEY HAVE UNDERFORECASTED THE SOUTHERN EXTENT OF THE
COOLER AIR. THIS WILL PLAY HAVOC WITH TEMPERATURE FORECASTS AS THE
BOUNDARY OSCILLATES AROUND THE CWFA. COOL AIR SHOULD REACH ITS
SOUTHERNMOST POSITION ON THURSDAY...AND THEN BEGIN RETREATING BY
FRIDAY AS WARM ADVECTION SETS UP FROM THE SOUTHEAST. SUFFICE IT TO
SAY THAT TEMPERATURE FORECASTS THIS PACKAGE ARE VERY LOW CONFIDENCE.

AS FAR AS PRECIP...TIMING IS ALSO A LOW CONFIDENCE ISSUE AS THE
MODELS TYPICALLY HAVE PROBLEMS RESOLVING INDIVIDUAL FAST MOVING
WAVES. BOTTOM LINE WILL BE PERIODS OF RAIN AND THUNDERSTORMS ALL
WEEK...WITH 12-24 HOUR BREAKS IN BETWEEN WAVES. THIS SHOULD ADD UP
TO QUITE A BIT OF RAIN...AND THE FLOOD POTENTIAL OUTLOOK WILL BE
REPLACED WITH A FLASH FLOOD WATCH THIS PACKAGE. WILL PLACE THE WATCH
ALONG AND NORTH OF I-20...AND WILL ONLY RUN IT THROUGH TONIGHT DUE
TO THE EXPECTED BREAK ON WEDNESDAY. HOWEVER...THE THREAT OF FLOODING
THIS WEEK WILL NOT BE LIMITED TO TONIGHT...NOR WILL IT BE LIMITED TO
THE NORTHERN AND CENTRAL CWFA.

EXTENDED FORECAST WILL BE TRENDED IN A WET DIRECTION DUE TO FORECAST
GULF LOW DEVELOPMENT.

THANKS TO MEG...SHV...AND BMX FOR COORDINATION.

PRELIM NUMBERS...
JAN 51/60/46/57 +466
MEI 51/62/47/59 +646

.JAN...
MS...FLASH FLOOD WATCH TONIGHT ZONES 018-019-025>052.
LA...FLASH FLOOD WATCH TONIGHT ZONES 007>009-015-016.
AR...FLASH FLOOD WATCH TONIGHT ZONES 074-075.
06

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>
074-281200-

HAZARDOUS WEATHER OUTLOOK...CORRECTED TIME
NATIONAL WEATHER SERVICE JACKSON MS
1125 AM CST TUE FEB 27 2001

...THUNDERSTORMS...
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING
ALONG AND WEST OF A YAZOO CITY TO BRANDON TO COLLINS TO PURVIS LINE.
NORTH OF INTERSTATE 20...THE MAIN THREAT WILL BE LARGE HAIL. ALONG
AND SOUTH OF INTERSTATE 20...ISOLATED DAMAGING DOWNBURST WINDS ARE
POSSIBLE IN ADDITION TO THE THREAT OF LARGE HAIL.

A STATIONARY FRONT EXTENDED FROM RAYVILLE LOUISIANA TO JUST SOUTH OF
COLUMBUS MISSISSIPPI THIS MORNING. THE AIRMASS ALONG AND SOUTH OF THIS
FRONT IS EXPECTED TO BECOME QUITE UNSTABLE THIS AFTERNOON.
THUNDERSTORMS WERE DEVELOPING ALONG THE FRONT LATE THIS MORNING...AND
ARE EXPECTED TO INTENSIFY DURING THE AFTERNOON HOURS WITH A FEW
STORMS POSSIBLY BECOMING SEVERE ALONG AND SOUTH OF THE FRONT. THE
AIRMASS WAS SOMEWHAT MORE STABLE OVER NORTHERN AND EAST CENTRAL
MISSISSIPPI...SO THE THREAT OF SEVERE WEATHER IS LESS OVER THIS AREA.

...FLOODING...
A FLASH FLOOD WATCH IS IN EFFECT FOR THIS AFTERNOON ALONG AND
NORTHWEST OF A RAYVILLE LOUISIANA TO VICKSBURG TO KOSCIUSKO TO WINONA
LINE. NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS
THIS AREA DURING THE AFTERNOON HOURS...WITH HEAVY RAINFALL POSSIBLY
CAUSING FLOODING OF RIVERS...CREEKS...AND LOW LYING AREAS. THE HEAVY
RAIN MAY PERSIST INTO TONIGHT...AND IF SO THE FLASH FLOOD WATCH WILL
BE EXTENDED OVER THIS AREA.

FARTHER TO THE SOUTH AND EAST...THE HEAVY RAINFALL IS EXPECTED TO BE
LESS WIDESPREAD AND NOT AS PERSISTENT. HOWEVER...THUNDERSTORMS MAY
PRODUCE BRIEF TORRENTIAL DOWNPOURS OF RAIN WHICH MAY CAUSE PONDING OF
WATER IN LOW LYING AND FLOOD PRONE AREAS.

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

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>
074-281200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
600 AM CST TUE FEB 27 2001

...THUNDERSTORMS...
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING
ALONG AND WEST OF A YAZOO CITY TO BRANDON TO COLLINS TO PURVIS LINE.
NORTH OF INTERSTATE 20...THE MAIN THREAT WILL BE LARGE HAIL. ALONG
AND SOUTH OF INTERSTATE 20...ISOLATED DAMAGING DOWNBURST WINDS ARE
POSSIBLE IN ADDITION TO THE THREAT OF LARGE HAIL.

A STATIONARY FRONT EXTENDED FROM RAYVILLE LOUISIANA TO JUST SOUTH OF
COLUMBUS MISSISIPPI THIS MORNING. THE AIRMASS ALONG AND SOUTH OF THIS
FRONT IS EXPECTED TO BECOME QUITE UNSTABLE THIS AFTERNOON.
THUNDERSTORMS WERE DEVELOPING ALONG THE FRONT LATE THIS MORNING...AND
ARE EXPECTED TO INTENSIFY DURING THE AFTERNOON HOURS WITH A FEW
STORMS POSSIBLY BECOMING SEVERE ALONG AND SOUTH OF THE FRONT. THE
AIRMASS WAS SOMEWHAT MORE STABLE OVER NORTHERN AND EAST CENTRAL
MISSISIPPI...SO THE THREAT OF SEVERE WEATHER IS LESS OVER THIS AREA.

...FLOODING...
A FLASH FLOOD WATCH IS IN EFFECT FOR THIS AFTERNOON ALONG AND
NORTHWEST OF A RAYVILLE LOUISIANA TO VICKSBURG TO KOSCIUSKO TO WINONA
LINE. NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS
THIS AREA DURING THE AFTERNOON HOURS...WITH HEAVY RAINFALL POSSIBLY
CAUSING FLOODING OF RIVERS...CREEKS...AND LOW LYING AREAS. THE HEAVY
RAIN MAY PERSIST INTO TONIGHT...AND IF SO THE FLASH FLOOD WATCH WILL
BE EXTENDED OVER THIS AREA.

FARTHER TO THE SOUTH AND EAST...THE HEAVY RAINFALL IS EXPECTED TO BE
LESS WIDESPREAD AND NOT AS PERSISTENT. HOWEVER...THUNDERSTORMS MAY
PRODUCE BRIEF TORRENTIAL DOWNPOURS OF RAIN WHICH MAY CAUSE PONDING OF
WATER IN LOW LYING AND FLOOD PRONE AREAS.

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