FXUS64 KLCH 102158
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
358 PM CST THU DEC 10 2009
.SYNOPSIS...
A COLD DOME OF HIGH PRESSURE NEAR MEMPHIS RIDGES SOUTH INTO THE
GULF OF MEXICO...ITS PERIPHERY BEING MARKED BY A COLD FRONT WHICH
EXTENDS WEST-SOUTHWEST THROUGH MIAMI TO ACROSS THE MIDSECTION OF
THE GULF OF MEXICO TO NEAR GULF POINT 24N 95W.
FURTHER-UP...THE SUBTROPICAL JET WILL CORE THROUGH LOWER BAJA
CALIFORNIA THROUGH LAREDO THROUGH NEW ORLEANS.
PRESSURES WILL BEGIN FALLING JUST OFFSHORE BROWNSVILLE BY NOON
FRIDAY...AS THE DOME OF HIGH PRESSURE MOVES EASTWARD. A FRONTAL
WAVE LOW FORMS BY FRIDAY AFTERNOON...BEFORE MOVING NORTHEAST...
AND REACHING THE WESTERN COASTAL WATERS BY SATURDAY AFTERNOON.
THE WAVE LOW LANDFALLS NEAR MARSH ISLAND BY EARLY SUNDAY MORNING...
WITH ITS ASSOCIATED COLD FRONT SWEEPING THROUGH THE COASTAL WATERS.
&&
.DISCUSSION...
FOR TONIGHT...THE WARM CONVEYOR BELT AIRSTREAM WILL BECOME
ESTABLISHED ACROSS THE WESTERN GULF COAST STATES. BAY-OF-CAMPECHE
AIR WILL STREAM IN ON THE SOUTHERLY CONVEYOR BELT...UPSLIDING THE
RECENTLY-ARRIVED CONTINENTAL POLAR AIR MASS. GULF CLOUDS AND
MOISTURE WILL DEEPEN ACROSS THE FORECAST AREA.
FURTHER-UP...PACIFIC CIRRUS WILL RIDE IN ON SOUTHWESTERLY WINDS
...THE PINEAPPLE EXPRESS WILL BE IN PLACE.
DESPITE THE CLOUD COVER AND FREE-AIR (OR GRADIENT-LEVEL) SOUTHERLY
WINDS...THE NIGHT-TIME TEMPERATURES WILL BE RUNNING FROM 5 TO
10 DEGREES BELOW NORMAL...DUE MAINLY TO ONGOING COLD-AIR ADVECTION
AT THE SURFACE.
FOR FRIDAY...RAIN IS EXPECTED TO BEGIN IN THE AFTERNOON. THE GFS
SOLUTION COMPUTES ADEQUATE SYNOPTIC LIFT AND DEEP TROPICAL MOISTURE
(PRECIPITABLE WATER VALUES APPROACHING 1.5 INCHES). THE LIMITING
FACTOR (FOR THUNDERSTORMS) WILL BE INSTABILITY (MAINLY ELEVATED
POTENTIAL CONVECTIVE INSTABILITY). IN GENERAL...OVERRUNNING RAIN
WITH A FEW EMBEDDED THUNDERSTORMS IS THE LIKELY SCENARIO.
RAIN WILL BE MODERATE-TO-HEAVY BY FRIDAY EVENING...AS THE WAVE LOW
DEEPENS WHILE MOVE UP THE TEXAS COAST.
&&
.MARINE...
NEAR GALE-FORCE WINDS ARE POSSIBLE OVER THE FARSHORE WATERS
STARTING FRIDAY AFTERNOON AND PERSISTING THROUGH FRIDAY EVENING.
ALSO...A STRONG EASTERLY STRESS UPON THE COASTAL WATERS WILL
GENERATE PERSISTENT EASTERLY SWELLS WHICH WILL REMAIN INTACT UNTIL
SATURDAY MORNING. THE PERSISTENT EASTERLY STRESS WILL INITIATE AN
EKMAN TRANSPORT OF WATER TO THE LOUISIANA AND UPPER TEXAS COASTS
...THE RISING TIDE STARTING BY FRIDAY AFTERNOON...LEVELING OFF
AROUND MIDNIGHT ON SATURDAY...BEFORE RECEDING BY SUNDAY MORNING.
THE CURRENT NUMERICAL GUIDANCE COMPUTES TIDES RUNNING ABOUT A FOOT
ABOVE THE NORMAL LUNAR TIDES...FROM FRIDAY EVENING THROUGH MIDNIGHT
SATURDAY. MINOR NUISANCE FLOODING IS POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 38 50 46 58 53 / 10 60 80 60 10
KBPT 39 51 47 55 54 / 10 60 80 60 10
KAEX 34 49 40 49 48 / 10 50 80 70 10
KLFT 37 49 46 57 55 / 10 60 80 70 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...GALE WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR THE
FOLLOWING ZONES: WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
EXTENDING FROM 20 NM TO 60 NM...WATERS FROM INTRACOASTAL
CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM TO 60 NM...
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM CST FRIDAY FOR THE FOLLOWING
ZONES: WATERS FROM CAMERON, LA TO HIGH ISLAND, TX EXTENDING
FROM 20 NM TO 60 NM...WATERS FROM INTRACOASTAL CITY, LA TO
CAMERON, LA EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY NIGHT TO 6 AM CST
SATURDAY FOR THE FOLLOWING ZONES: WATERS FROM CAMERON, LA
TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS
FROM INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20
NM TO 60 NM...WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO
CAMERON, LA OUT 20 NM...COASTAL WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA OUT 20 NM.
&&
TRARES
$$
