Flash Flood Warning 50, NWS Lake Charles, LA

SOUTHEAST TEXAS..SOUTHWEST AND CENTRAL LOUISIANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
135 PM CDT FRI SEP 11 1998

TROPICAL STORM FRANCES IS MOVING LITTLE AT THIS TIME. FOR NOW...HEAVY
RAINS WILL SLOWLY TAPER OFF INTENSITY-WISE INTO THE EARLY EVENING
HOURS THOUGH THE COVERAGE WILL CONTINUE TO BE WIDESPREAD. TONIGHT THE
SYSTEM IS EXPECTED TO INHALE...BRINGING A NEW ONSLAUGHT OF RAIN AND
THUNDERSTORM ACTIVITY...POSSIBLY ENDING OUR SEVERE DROUGHT.
COORDINATED WITH SPC ON THE TORNADO WATCH AND AGREED THAT...FOR
NOW...THE MAIN THREAT WOULD BE RAINFALL AND FLOODING...NOT TORNADOES.
HOWEVER...ISOLATED TORNADOES REMAIN POSSIBLE NEAR THE COAST DUE TO
FRICTIONAL EFFECTS OF THE TOPOGRAPHY AND THE LOW LEVEL WIND SHEAR.

SEVERAL CHARACTERS ARE AT PLAY WHICH WILL AFFECT THE FUTURE COURSE
OF FRANCES. AN UPPER LOW (200 HPA) IS CUTTING OFF IN NORTHEAST
MEXICO...JUST TO THE SOUTHWEST OF THE TROPICAL CYCLONE. THE PROXIMITY
OF THIS UPPER LOW WILL DO WHAT THE PREVIOUS ONE DID TO THE ONLY SYSTEM
2-3 DAYS AGO...MAKE IT MORE BAROCLINIC...IN OTHER WORDS MORE
EXTRATROPICAL WITH TIME. THIS TRANSITION SHOULD TAKE A DAY OR TWO.
ALSO, THIS COULD STEER THE SYSTEM TO THE NORTHWEST WITH TIME.

HOWEVER, THE ETA AND THE AVN (THOUGH TO A LESSER EXTENT) BUILD THE
500 HPA RIDGE OVER THE CENTRAL UNITED STATES SOUTHWESTWARD. ALL
THIS SEEMS TO HINGE ON HOW STRONG THE SHORTWAVE IS THAT IS
ANCHORED IN THE WESTERN U.S. AT THIS TIME. THESE FACTORS WOULD PUSH
THE CYCLONE ON A MORE SOUTHWEST TRACK TO THE RIO GRANDE BASIN AND
NORTHEAST MEXICO BY 48 HOURS...AN AREA WHERE MEMORIES OF CHARLEY AND
ITS FLOODING ARE STILL FRESH. THE CURRENT SATELLITE LOOP SEEMS TO BE
INDICATING THIS TREND BY THE SYSTEM REORIENTING ITSELF IN A SW-NE
ORIENTATION. THIS IS QUITE SIMILAR TO WHAT CARLA DID IN 1961 AND
BEULAH IN 1967....BOTH CREATED SEVERE RIVER FLOODING ACROSS TEXAS.
THIS TRACK WOULD DROP OFF OUR RAIN CHANCES TO VIRTUALLY NIL ON
SUNDAY.

THE CURRENT FORECAST REFLECTS THIS THINKING AND BLENDS IT WITH THE
PREVIOUS FORECAST. THIS WILL MAKE THE FORECAST A DRIER SOLUTION THAN
THE NGM MOS BRINGS FORTH ON SUNDAY. RAINFALL WILL CONTINUE UNTIL
TOMORROW TONIGHT AS THE SYSTEM SLOWLY MOVES SOUTHWEST...TAKING ITS
BANDING RAINS FURTHER SOUTHWEST INTO HOUSTONS COUNTY WARNING AREA BY
TOMORROW NIGHT. THE TEMPERATURE FORECAST FOLLOWS FROM THIS AND TAKES
CLIMATOLOGY AND PERSISTENCE (ON LOWS) INTO ACCOUNT. NGM MOS WAS ALMOST
UNUSABLE.

WINDS WILL STAY UP THROUGH THE WEEKEND...KEEPING THE AREA IN COASTAL
FLOOD. WHEN THE TROPICAL STORM WARNINGS COME DOWN...COASTAL FLOOD
WARNINGS WILL BE ISSUED FOR OUR ENTIRE COUNTY WARNING AREA.

BPT 75/83/75/87 +853
LCH 75/83/75/90 +842
LFT 75/83/75/90 +842
AEX 73/85/73/90 8732