Flash Flood in Louisiana, August 6, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
320 AM CDT TUE AUG 6 2002

MAIN NEAR TERM FORECAST ISSUE IS TD BERTHA...CURRENTLY LOCATED JUST
NORTH OF BATON ROUGE WITH SIGNIFICANT FLARE-UP OF CONVECTION
OVERNIGHT OVERNIGHT IN AREAS N AND NW OF LAKE PONTCHARTRAIN. SLOW
DRIFT TO W NOTED DURING THE EARLY MORNING HOURS...AND GUIDANCE FROM
ETA AND AVN SUGGEST SLOW W OR SW MOTION NEXT 24 HOURS OR SO. SOME
WEAKENING OCCURS IN CIRCULATION DURING NEXT 24 HOURS. WITH MOST OF
FORECAST AREA IN WETTER E PERIHPERY OF CIRCULATION...WILL LEAVE POPS
IN LIKELY CATEGORY AND MENTION HEAVY RAINFALL POSSIBLE.  CONVECTION
ONGOING...WILL LEAVE FLASH FLOOD WATCH IN PLACE TODAY FROM THE
GREATER BTR AREA AND SW MS EWD TO AREAS N OF LAKE PONTCHARTRAIN.

BEYOND THE SHORT TERM FORECAST...DIGGING TROUGH OVER EAST COAST ON
WED AND THU ALLOWS SURFACE FRONTAL BOUNDARY TO SAG TO TOWARD S AL
AND S GA.  WHILE DRIER AIR MOVES INTO THE MID LEVELS FROM THE E AND
NE...LOWER TROP REMAINS FAIRLY MOIST. SOME CONVERGENCE ALONG
BOUNDARY AND SUFFECIENT LOW LEVEL MOISTURE SHOULD ALLOW POPS TO
REMAIN NEAR OR ABOVE NORMAL MID TO LATE WEEK. BY WEEKEND...E COAST
TROUGH MOVES EWD...WITH MID LATITUDE TROUGH MOVING THROUGH THE
PLAINS. SUFFECIENT MOISTURE WILL CONTINUE TO SUPPORT SCATTERED
NORMAL DAYTIME AND EVENING THUNDERSTORM ACTIVITY.

PRELIM TEMPS AND POPS
MCB 89/71/93/72 7242  BTR 89/74/92/73 7242
MSY 89/75/93/74 6343  GPT 89/74/89/77 5232

.NEW...NONE
LA...FLASH FLOOD WATCH EAST CENTRAL/SOUTHEAST LA/LAZ034>040-046>050
MS...FLASH FLOOD WATCH SOUTHWEST MS MSZ068>071

21

LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-070030-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1200 PM CDT TUE AUG 6 2002

...A FLASH FLOOD WATCH IS IN EFFECT TODAY AND TONIGHT ACROSS PORTIONS
OF EAST CENTRAL AND SOUTHEAST LOUISIANA...NORTH OF A LINE FROM THE
ATCHAFALAYA RIVER SOUTHWEST OF BATON ROUGE...TO SLIDELL...AND
EXTENDING NORTH INTO EXTREME SOUTHWEST MISSISSIPPI...

.SYNOPSIS...THE STATIONARY REMNANTS OF TROPICAL DEPRESSION BERTHA
WERE LOCATED NORTH OF BATON ROUGE THIS MORNING. AN UNSTABLE AIRMASS
WITH ABUNDANT TROPICAL MOISTURE WILL CONTINUE OVER SOUTHEAST
LOUISIANA AND EXTREME SOUTH MISSISSIPPI THROUGH TONIGHT PRODUCING A
THREAT OF HEAVY RAINFALL.

.THUNDERSTORMS AND FLOODING...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR TODAY AND
TONIGHT. ADDITIONAL RAINFALL AMOUNTS OF 2 TO 4 INCHES WITH LOCAL
AMOUNTS NEAR 5 INCHES ARE EXPECTED. TORRENTIAL RAIN REMAINS FOCUSED
OVER EAST FELICIANA...AND WESTERN PARTS OF ST HELENA AND LIVINGSTON
PARISHES LATE THIS MORNING. THE HEAVY RAIN HAS DISSIPATED OVER HARD
HIT ST TAMMANY PARISH. HOWEVER...ITS POSSIBLE THAT HEAVY RAIN WILL
REDEVELOP OVERNIGHT ACROSS PORTIONS OF SOUTHWEST MISSISSIPPI...AND
EAST CENTRAL AND SOUTHEAST LOUISIANA FROM THE BATON ROUGE AREA TO THE
NORTH SHORE OF LAKE PONTCHARTRAIN. THIS INCLUDES HARD HIT AREAS OF
NORTHERN ST TAMMANY PARISH.

SOUTH OF LAKE PONTCHARTRAIN AND ALONG THE MISSISSIPPI COAST BANDS OF
SHOWERS AND THUNDERSTORMS MAY PRODUCE LOCALIZED HEAVY RAINFALL OF
NEAR 2 INCHES IN AN HOUR MAINLY TODAY. THE HEAVY RAIN MAY RESULT IN
FLOODING OF STREAMS...BAYOUS...AND AREAS OF POOR DRAINAGE. IN
ADDITION TO HEAVY RAIN...THUNDERSTORMS WILL ALSO PRODUCE OCCASIONAL
TO FREQUENT LIGHTNING AND WIND GUSTS AS HIGH AS 30 MILES PER HOUR.

.MARINE HAZARDS...
SCATTERED SHOWERS AND THUNDERSTORMS WILL HAVE THE POTENTIAL TO
PRODUCE WATERSPOUTS IN THE COASTAL WATERS AND TIDAL LAKES
TODAY.

FOR MORE INFORMATION...VISIT OUR WEB SITE AT WWW.SRH.NOAA.GOV/LIX
(ALL LOWER CASE).