Flash Flooding in Louisiana, March 1 to 3, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
240 PM CST THU MAR 1 2001

VERY WET CONDITIONS WILL CONTINUE ACROSS THE ENTIRE FORECAST AREA
INTO SATURDAY NIGHT. SHORT WAVES CONTINUE TO MOVE RAPIDLY EASTWARD
ACROSS THE FORECAST AREA AS THE UPPER AIR WINDS BLOW NORTHEASTWARD
ACROSS TEXAS AROUND A DEEP TROUGH WHICH IS SOUTH OF SOUTHERN
CALIFORNIA. A CLOSED 500MB LOW IS LOCATED NEAR BAJA CALIFORNIA.
MODELS HAVE HAD A DIFFICULT TIME FORECASTING THE SHORT WAVES AND
ASSOCIATED PRECIPITATION IN THIS WEATHER PATTERN. BUT...MODELS ARE
IN GENERAL AGREEMENT THAT WET WEATHER WILL PERSIST WELL INTO
SATURDAY BEFORE THE UPPER TROUGH FINALLY MOVES FAR ENOUGH EAST TO
PUSH THE SURFACE LOW EAST OF THE FORECAST AREA. THE HEAVIEST
RAINFALL IN THE FORECAST AREA IS MOST LIKELY TO OCCUR FRIDAY
AFTERNOON INTO FRIDAY NIGHT AS A WARM FRONT IS PUSHED NORTHWARD INTO
SOUTHERN MISSISSIPPI WITH CONSIDERABLE RAINFALL EXPECTED ACROSS THE
FORECAST AREA BOTH NORTH AND SOUTH OF THE FRONT. A SURFACE LOW WILL
TRACK ALONG THIS FRONT INTO SOUTHERN MISSISSIPPI ON FRIDAY NIGHT.

A FLASH FLOOD WATCH WAS ISSUED EARLY THIS MORNING FOR ALL BUT THE
THREE MOST SOUTHEASTERN COUNTIES IN THE FORECAST AREA (MARION, LAMAR
AND FOREST). IT NOW APPEARS THE HEAVIER RAIN WILL HOLD OFF TILL
TONIGHT WITH MOST WIDESPREAD RAIN LATER ON FRIDAY. MAY CUT BACK ON
FLASH FLOOD WATCH AREA SLIGHTLY IN SOUTHEASTERN SECTIONS OF FORECAST
AREA WHEN WE PRODUCE A NEW FLASH FLOOD WATCH PRODUCT LATER THIS
AFTERNOON. HOWEVER...WE WILL MOST LIKELY NEED TO CONTINUE A FLASH
FLOOD WATCH FOR MOST OF THE FORECAST AREA WELL INTO SATURDAY AS
THUNDERSTORMS WITH TRAINING PRECIPITATION CELLS OVER SATURATED
GROUND MAY CAUSE WATER TO RISE RAPIDLY ALONG RIVERS...CREEKS...
DRAINAGE DITCHES...AND OTHER LOW LYING AREAS.

THERE COULD ALSO BE A CHANCE OF SOME SEVERE THUNDERSTORMS IN
PORTIONS OF THE FORECAST AREA FROM SOUTHWEST TO EAST CENTRAL
MISSISSIPPI AND SOUTHWARD ON FRIDAY AFTERNOON AND FRIDAY NIGHT AS A
FEW STRONGER STORMS MAY PRODUCE GUSTY WINDS AND LARGE HAIL.

ONE MORE THING TO DISCUSS IN THE SHORT TERM PERIOD IS THE LATEST
RADAR IMAGERY. THUNDERSTORMS NOW MOVING INTO CHICOT COUNTY ARKANSAS
ARE LIKELY TO WEAKEN AS THEY MOVE FARTHER EAST THIS AFTERNOON.
HOWEVER...EXPECT RAIN AND A FEW THUNDERSTORMS TO CONTINUE TO MOVE
INTO SOUTHEAST ARKANSAS...NORTHEAST LOUISIANA...AND WESTERN
MISSISSIPPI THIS EVENING AND TONIGHT. ANOTHER AREA OF SHOWERS AND
THUNDERSTORMS WILL SPREAD NORTHEASTWARD INTO SOUTHWEST MISSISSIPPI
INTO THE EARLY EVENING HOURS.

TEMPERATURE FORECAST WILL BE A BIT OF A CHALLENGE THE NEXT SEVERAL
DAYS AS A FRONTAL BOUNDARY CONTINUES TO BE ORIENTED WSW TO ENE
ACROSS SOUTHERN PORTIONS OF MISSISSIPPI THROUGH SATURDAY. WILL GO
MOST CLOSELY WITH THE AVN MOS GUIDANCE THROUGH THE PERIOD.

QPF DISCUSSION:  WILL GO ALONG WITH NCEP GUIDANCE (SIMILAR TO AVN QPF
FORECAST) FOR A BROAD AREA OF .50 INCH AMOUNTS IN MUCH OF NORTHEAST
LOUISIANA AND WEST CENTRAL MISSISSIPPI FROM 00 TO 06Z TONIGHT AND
OVER EAST CENTRAL AND SOUTHEAST MISSISSIPPI FROM 06 TO 12Z. THEN
AREAL AVERAGES OF AROUND ONE HALF INCH AGAIN FROM 12Z TO 18Z AND
FROM 18Z TO 00Z DURING THE DAY ON FRIDAY. MUCH OF THE FORECAST AREA
COULD RECEIVE AROUND 2 INCHES OF RAIN FOR THE 24 HOUR PERIOD ENDING
AT 00Z SATURDAY...WITH MUCH MORE RAIN TO COME AFTER THAT.

EXTENDED FORECAST
RAIN AND THUNDERSTORMS SHOULD FINALLY PUSH OUT OF THE AREA ON SUNDAY
WITH DRY CONDITIONS LIKELY THROUGH THURSDAY. TEMPERATURES SUNDAY
THROUGH THURSDAY SHOULD BE A BIT COOLER THAN NORMAL WITH SLOWLY
MODERATING TEMPERATURES THROUGH THE PERIOD.

PRErLIM NUMBERS:
JAN 56/62/53/63  9999
MEI 56/66/57/69  9999

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

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