FXUS64 KLCH 090424
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1024 PM CST TUE DEC 8 2009
.DISCUSSION...
PRE-FRONTAL BAND OF SHOWERS AND THUNDERSTORMS CURRENTLY MOVING
THROUGH EAST CENTRAL LOUISIANA AND WILL BE HEADING INTO SOUTH
CENTRAL LOUISIANA SHORTLY. THIS ACTIVITY SHOULD BE OUT OF THE AREA BY
MIDNIGHT...SO POPS AFTER 06Z WERE DROPPED. TORNADO WATCH FOR
RAPIDES AND AVOYELLES PARISHES WAS ALLOWED TO EXPIRE ON
SCHEDULE...AND THE SEVERE WEATHER THREAT SOUTH OF THIS AREA THE
REMAINDER OF THE EVENING APPEARS MINIMAL. HOURLY TEMPERATURES
AND DEWPOINTS WERE RUNNING WELL ABOVE PREVIOUS FORECAST...SO
CONSIDERABLE ADJUSTMENTS WERE MADE TO FORECAST LOWS.
SFC WINDS ARE GRADUALLY TAKING ON A MORE WESTERLY COMPONENT...AND
THIS WILL CONTINUE AS PRE-FRONTAL TROF MARKING THE LEADING EDGE OF
DRIER AIR PUSHES EAST THROUGH THE AREA DURING THE REST OF THE
EVENING AND OVERNIGHT HOURS. TRUE FRONT...CURRENTLY MOVING THROUGH
SOUTHERN AND EASTERN OKLAHOMA...WILL DRIVE THROUGH THE AREA THE
FIRST HALF OF TOMORROW...USHERING IN EVEN DRIER AND MUCH COOLER
AIR. THIS WILL BLAST AWAY WHATEVER LOW CLOUDS/FOG ARE
PRESENT...LEADING TO A MOSTLY SUNNY...BREEZY...AND COOL WEDNESDAY.
HAVE BEEN MONITORING SFC OBS AND LATEST AVAILABLE GUIDANCE TO TRY
AND GET A HANDLE ON THE FOG POTENTIAL OVERNIGHT INLAND AND OVER
THE NEARSHORE WATERS AND COASTAL LAKES AND BAYS. IT APPEARS THAT
SIGNIFICANT DRYING ALOFT WILL OCCUR TONIGHT LONG BEFORE FRONTAL
PASSAGE TOMORROW MORNING SCOURS OUT THE LOW LEVEL MOISTURE...WITH A
NEAR SURFACE MOIST LAYER REMAINING AMID THE LIGHT SOUTHWEST TO
WESTERLY FLOW. GIVEN THE RECENT DROP IN WINDS...CEILINGS...AND
VISIBILITIES AT KLCH AND KBPT...AND 00Z NUMERICAL GUIDANCE AND
MODEL OUTPUT THAT CONTINUES TO SUPPORT FOG...WILL LEAVE THE
ADVISORIES AS IS BUT CONTINUE TO MONITOR TRENDS.
&&
.PREV DISCUSSION... /ISSUED 722 PM CST TUE DEC 8 2009/
AVIATION...IFR CIGS WITH MVFR VIS REMAINS THE RULE ALONG AND
SOUTH OF I-10. AEX IN CEN LA HAS BETTER CONDITIONS WITH MVFR CIGS.
THIS IS ALL DUE TO A WEAKENING FRONTAL BOUNDARY MOVING SOUTHEAST
AND APPROACHING THE TERMINAL FCST AREA WHERE GULF MOISTURE TO 8K
FEET AWAITS. THE LOW LEVEL JET HAS DECOUPLED WITH WINDS
DIMINISHING THIS EVENING. AS WINDS DROP BELOW 8 KNOTS...LIFR CIGS
WILL MEET WITH THE SFC AND PRODUCE LIFR VIS BY MIDNIGHT. THE FRONT
WILL WASH OUT AS IT CROSSES THE AREA. DRIER AIR FILTERING IN FROM
THE NORTHWEST WILL RAPIDLY IMPROVE CONDITIONS BY AROUND 4AM.
SWEENEY
PREV DISCUSSION... /ISSUED 403 PM CST TUE DEC 8 2009/
DISCUSSION...
A WARM FRONT BACKED ACROSS THE REGION TODAY WITH TEMPERATURES
WARMING INTO THE 70S... CLOUDY SKIES AND RAINY WEATHER THROUGHOUT
MOST OF THE DAY. DEWPOINTS ARE RUNNING INTO THE UPPER 6OS WITH
CAPES AROUND 900 J/KG AND HEL ABOVE 400 J/KG. BEST POTENTIAL FOR
SVR WX IS EXPECTED INTO CNTRL LA THIS EVE AS THE FRONT PULLS NORTH
AND THE DEPTH OF THE INSTABILITY WILL BE THE STRONGEST.
NOW FOR THE REST OF THE AREA... SHOWERS/RAIN MIXED WITH WINDS
DECREASING AND AREAS OF DENSE FOG DEVELOPING AROUND MIDNIGHT AND
CONTINUING THROUGH THE FRONTAL PASSAGE EARLY TMRW MRNG. AFTERNOON
TEMPS TMRW ARE NOT EXPECTED TO RECOVER BEYOND THE UPR 50S/LWR 60S.
SKIES CLEARING LATE WEDNESDAY INTO THURSDAY. WE ARE IN A VERY
RAINY PATTERN WITH MORE RAIN EXPECTED IN FRIDAY EVE.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 58 58 37 56 / 40 10 0 10
KBPT 55 55 37 56 / 10 10 0 10
KAEX 53 55 31 52 / 10 10 0 10
KLFT 62 62 37 56 / 40 10 0 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...DENSE FOG ADVISORY UNTIL 6 AM CST WEDNESDAY FOR ACADIA-CALCASIEU-
CAMERON-IBERIA-JEFFERSON DAVIS-LAFAYETTE-LOWER ST. MARTIN-
ST. MARY-UPPER ST. MARTIN-VERMILION.
TX...DENSE FOG ADVISORY UNTIL 6 AM CST WEDNESDAY FOR JEFFERSON-ORANGE.
GM...DENSE FOG ADVISORY UNTIL 8 AM CST WEDNESDAY FOR CALCASIEU LAKE-
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-SABINE LAKE-VERMILION BAY.
&&
$$
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