Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 100524
AFDLCH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1124 PM CST TUE FEB 9 2010

.DISCUSSION...
FOR THE 10/06Z TAF ISSUANCE.

&&

.AVIATION...
NO REAL CHANGES TO THE AVIATION FORECAST TONIGHT WITH VFR
CONDITIONS EXPECTED TO PREVAIL FOR THE NEXT 24 HOURS. FAIRLY QUIET
WEATHER CURRENTLY WITH HIGH PRESSURE AT THE SURFACE CONTINUING TO
BUILD IN AND PRODUCE DRY CONDITIONS IN THE LOW LEVELS. MEANWHILE...UPPER
LEVEL MOISTURE IS BEGINNING TO MOVE INTO THE REGION FROM THE EAST
PACIFIC RIDING IN ON A FAST SOUTHERN JET STREAM.

MOISTURE WILL CONTINUE TO STREAM IN FROM THE WEST WITH THE
SOUTHERN JET WITH CLOUDS IN THE UPPER LEVELS BEGINNING TO THICKEN
BY MORNING AND LOWERING INTO THE MID LEVELS BY LATE AFTERNOON AND
ON WEDNESDAY EVENING.

RUA


&&

.PREV DISCUSSION... /ISSUED 805 PM CST TUE FEB 9 2010/

UPDATE...LOOKS LIKE THE COMBINATION OF UPPER LEVEL PACIFIC
MOISTURE MOVING IN FROM THE WEST AND A SUSTAINED GRADIENT AT THE
SURFACE MAINTAINING LIGHT WINDS TNITE WILL BE SUFFICIENT TO
PRECLUDE A HARD FREEZE. JUST A LIGHT FREEZE AREAWIDE OVERNIGHT.

MARINE...WINDS ARE DIMINISHING ON SCHEDULE AS HIGH PRESSURE
GRADUALLY BUILDS IN FROM THE NORTHWEST. THIS WILL ALLOW THE INNER
WATERS SMALL CRAFT ADVISORY TO EXPIRE AT 9 PM.

SWEENEY

PREV DISCUSSION... /ISSUED 512 PM CST TUE FEB 9 2010/

DISCUSSION...
CLOUDS CLEARED OUT NICELY TODAY GIVING WAY TO SUNNY ALBEIT COOL
AND BREEZY DAY. DEWPOINTS HAVE DROPPED INTO THE TEENS AND 20S AS
COLD CANADIAN AIR CONTINUES TO SPILL INTO THE REGION IN THE WAKE
OF THE FRONT THAT MOVED THROUGH THE AREA LAST NIGHT. WITH HIGH
PRESSURE STARTING TO SETTLE INTO THE AREA TONIGHT...WINDS ARE
EXPECTED TO DECREASE THOUGH NOT GO COMPLETELY CALM. STILL...UNDER
A CLEAR SKY...TEMPERATURES DROP QUICKLY AFTER SUNSET AMID THIS DRY
CONTINENTAL AIRMASS...AND HAVE GONE WITH LOWS BELOW FREEZING OVER
ALL AREAS EXCEPT THE IMMEDIATE COAST. THE DURATION OF TEMPERATURES
IN THE UPPER 20S OVER THE EAST TEXAS LAKES AND CENTRAL LOUISIANA
IS EXPECTED TO BE BRIEF...THUS DID NOT ISSUE A HARD FREEZE WARNING.

MID/UPPER LEVEL MOISTURE WILL BEGIN STREAMING INTO THE AREA FROM
THE WEST TOMORROW AHEAD OF AN INCOMING STORM SYSTEM CURRENTLY JUST
OFF THE CA COAST. COLD HIGH PRESSURE WILL CONTINUE TO PREVAIL AT
THE SURFACE...AND WITH THE DECREASED INSOLATION COURTESY OF THE
INCREASING CLOUD COVER...HIGHS TOMORROW ARE EXPECTED TO STRUGGLE
TO REACH THE UPPER 40S TO NEAR 50.

AS THE AFOREMENTIONED MID/UPPER LEVEL LOW SLIDES INTO NORTHERN
MEXICO TOMORROW EVENING...ISENTROPIC LIFT IS FORECAST TO COMMENCE
OVER CENTRAL TEXAS...AND SPREAD EAST THROUGH THE OVERNIGHT HOURS.
FORECAST SOUNDINGS SHOW A CONSIDERABLE AMOUNT OF DRY AIR UNDERNEATH
THE MID/UPPER LEVEL MOISTURE THAT IS GOING TO TAKE SOME TIME TO
SATURATE...SO I DO NOT ANTICIPATE MUCH PRECIPITATION REACHING THE
GROUND OVERNIGHT WEDNESDAY. ONE DILEMMA IS THAT BY EARLY
THURSDAY...THE DRY LAYER SHOWN BY SOME MODELS IS QUITE
SHALLOW...AND COULD SATURATE VIA DIABATIC PROCESSES SOONER THAN
MODELS ARE INDICATING. SHOULD THAT OCCUR...A SATURATED TEMPERATURE
PROFILE THAT IS MOSTLY SUB FREEZING WOULD RESULT.
CONSEQUENTLY...HAVE STARTED THE POSSIBILITY OF WINTRY PRECIP AFTER
MIDNIGHT WEDNESDAY.

THE FORECAST DILEMMA THROUGH THURSDAY INTO FRIDAY MORNING BECOMES
ONE OF THE TEMPERATURE PROFILE...WITH SOME FAIRLY SIGNIFICANT
DIFFERENCES IN THE FORECAST MODELS TO CONTEND WITH. UTILIZED
SEVERAL PRECIPITATION TYPE TECHNIQUES ON MULTIPLE MODELS...AND THE
WORST SCENARIO I ARRIVED AT WAS A STRIPE OF 2-4 INCHES GENERALLY
ALONG AND NORTH OF A LINE FROM WOODVILLE TEXAS TO OPELOUSAS
LOUISIANA...WITH THE RAIN/SNOW LINE COMING AS FAR SOUTH AS THE I-10
CORRIDOR. THE BEST CASE SCENARIO IS AREAWIDE COLD RAIN. AS YOU CAN
SEE...THE SPECTRUM OF POSSIBILITIES IS QUITE LARGE...AND AT THIS
TIME...A FORECAST OF DEFINITIVE WINTER PRECIPITATION TYPE OR ANY
ACCUMULATION THEREOF IS QUITE DIFFICULT.

GIVEN THIS LOW DEGREE OF CONFIDENCE...OPTED TO CARRY A RAIN/SLEET/SNOW
MIX RATHER THAN HANG MY HAT ON ONE TYPE OR THE OTHER...AND NO
ACCUMULATIONS.

FORECAST BEYOND DAY 4 UNCHANGED.

MARINE...
GUSTY NORTH WINDS AND ROUGH SEAS WILL CONTINUE THIS EVENING IN THE
WAKE OF A COLD FRONT THAT MOVED THROUGH THE COASTAL WATERS LAST
NIGHT. WINDS WILL START TO DIMINISH TONIGHT INTO WEDNESDAY
MORNING. A GULF LOW IS FORECAST TO DEVELOP ON THURSDAY...BRINGING
PROLONGED WIDESPREAD PRECIPITATION WITH MODERATE EAST TO NORTHEAST
WINDS AS IT TRACKS EAST ACROSS THE NORTHERN GULF THURSDAY AND
THURSDAY NIGHT.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
KLCH  30  50  32  44  34 /   0  10  30  80 100
KBPT  30  50  33  43  35 /   0  10  40  90 100
KAEX  30  48  29  43  31 /   0  10  20  50 100
KLFT  31  49  32  44  33 /   0  10  20  70 100

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 AM CST WEDNESDAY 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.

&&

$$







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