FXUS64 KLCH 081129
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
529 AM CST TUE DEC 8 2009
.AVIATION...
FOR THE 08/12Z TAF ISSUANCE...
COASTAL FRONT WAVING AROUND THE FORECAST AREA EXTENDING FROM JUST
OFFSHORE SOUTHEAST TEXAS INTO SOUTH CENTRAL LOUISIANA. EXPECT THIS
FRONT TO SURGE INLAND TODAY AS A WARM FRONT AS LOW PRESSURE IN THE
CENTRAL PLAINS DEEPENS AND HELPS TO INCREASE SOUTHERLY WINDS.
TAFS DURING THE MORNING WILL BE MAINLY IFR/LIFR CEILINGS WITH
MVFR/IFR VISIBILITIES IN LOW CLOUDS AND FOG. AS THE SOUTHERLY
WINDS INCREASE BY 08/18Z...WITH GUSTS AROUND 25 KNOTS. EXPECT
VISIBILITIES TO INCREASE...HOWEVER CEILINGS SHOULD STAY IN THE
HIGH END IFR/LOW END MVFR. THERE ALSO WILL BE SOME SCATTERED
STORMS AROUND.
A COLD FRONT IS EXPECTED TO MOVE THROUGH LATE TONIGHT. STILL
EXPECT SOME LOW CLOUDS AND PATCHY FOG AS LOW LEVEL MOISTURE
BECOMES TRAPPED UNDER FRONTAL INVERSION...AND DRIER AIR DOES NOT
FULLY FILTER IN UNTIL AFTER THE END OF THIS TAF PACKAGE.
RUA
&&
.PREV DISCUSSION... /ISSUED 513 AM CST TUE DEC 8 2009/
SYNOPSIS...
UPPER LOW NOTED OVER THE WRN CONUS...PRODUCING SWRLY FLOW ALOFT
OVER THE AREA. A SFC FRONT EXTENDS FROM THE COAST NEAR GLS...NE
TOWARD BPT...LCH AND MCB. THE FRONT...WHICH WAS CROSSING THE
COASTAL WATERS AND SOUTHERN LA AT THIS TIME YESTERDAY...IS NOW
MOVING BACK NORTH AS A WARM FRONT. SOUTH OF THIS BOUNDARY...WINDS
ARE SOUTHEASTERLY WITH DEWPOINTS INTO THE LOWER 60S...WHILE NORTH
OF IT...DEWPOINTS WERE IN THE MID 50S WITH NORTHEASTERLY WINDS.
A DISTURBANCE RIDING OVER THE FRONT HAS PRODUCED WIDESPREAD RAIN
AND A FEW THUNDERSTORMS ACRS SE LA. MUCH OF THIS ACTIVITY IS
MOVING EAST AND NOW LEAVING THE LCH CWA...WITH ONLY A BAND OF
SHOWERS...MARKING THE SFC FRONT...LIFTING NORTH ACRS SE TX INTO SW
LA.
DISCUSSION...
STILL LOOKS LIKE IT COULD BE AN ACTIVE DAY ACRS THE AREA TODAY AS
THE WARM FRONT MOVES FURTHER INLAND...USHERING IN UNSEASONABLY
WARM AND MOIST AIR. STILL EXPECT TO SEE DEWPOINTS INTO THE UPPER
60S THIS AFTN AS ABUNDANT GULF MOISTURE OVERSPREADS THE AREA. AS
THE UPPER TROUGH AXIS PULLS INTO THE SRN PLAINS...A SFC LOW WILL
DEVELOP OVER THE TX PANHANDLE AND MOVE INTO OK. THE PRESSURE
GRADIENT WILL TIGHTEN ACRS THE AREA AS THIS LOW DEEPENS...ALLOWING
STRONG GUSTY SOUTHERLY WINDS TO DEVELOP. EXPECT TO SEE WIND SPEEDS
IN THE 20 TO 25 MPH RANGE WITH HIGHER GUSTS MAINLY ALONG AND
SOUTH OF INTERSTATE 10. THUS...HAVE ISSUED A LAKE WIND ADVISORY
FOR THIS AREA.
THE OTHER ISSUE FOR TODAY IS THE POTENTIAL FOR SEVERE WEATHER. SPC
CONTINUES TO DEPICT THE AREA IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS...MAINLY FOR POSSIBLE DAMAGING THUNDERSTORM WINDS
AND A FEW TORNADOES. SUFFICIENT DEEP LAYER SHEAR ALONG WITH A
STRONG 50 TO 60 KT LLJ TO DEVELOP THROUGH MIDDAY...WITH 0-1 KM
HELICITIES BETWEEN 200-300 M2/S2. ALTHOUGH THESE PARAMETERS ARE
SUGGESTIVE OF THE POTENTIAL FOR SEVERE WEATHER...INSTABILITY
CONTINUES TO BE MARGINAL. FEEL THAT ANY SEVERE THREAT WILL BE
ISOLATED...MAINLY FOR LOCATIONS FROM NEAR THE LAKES AREA EAST INTO
CNTRL LA.
DRIER AIR WILL BEGIN TO MOVE INTO THE AREA OVERNIGHT TUESDAY AS
THE FRONT PUSHES THROUGH EARLY WEDNESDAY MORNING. DRIER AND
COOLER WEATHER WILL RETURN TO THE AREA WEDNESDAY INTO THURSDAY AS
CANADIAN HIGH PRESSURE BUILDS INTO THE REGION. CONTINUE TO EXPECT
BELOW NORMAL TEMPERATURES...WITH LOWS THURSDAY MORNING IN THE
LOWER 30S NORTHERN ZONES TO UPPER 30S SOUTHERN ZONES.
NEXT CHANCE FOR RAIN COMES FRIDAY INTO SATURDAY AS A LOW DEVELOPS
OVER THE NORTHWEST GULF AND MOVES EAST. BEYOND THIS
TIME FRAME...MODEL SOLUTIONS BEGIN TO DIVERGE QUITE A BIT WITH THE
GFS DRIER OVER THE LATTER PORTION OF THE WEEKEND AND THE ECMWF
KEEPING SOME PRECIPITATION OVER THE AREA. WITH LOW CONFIDENCE IN
THE EXTENDED...HAVE MADE FEW CHANGES TO CURRENT GRIDS.
MARINE...
A STALLED FRONTAL BOUNDARY OVER THE COASTAL WATERS THIS MORNING
WILL LIFT BACK NORTH TODAY. PATCHY FOG ALONG THE COAST INCLUDING
THE INTER-COASTAL WATERWAYS CAN BE EXPECTED EARLY THIS MORNING.
WINDS WILL BECOME SOUTHERLY AND STRENGTHEN TO 20 TO 25 KNOTS BY
MIDDAY AS LOW PRESSURE DEVELOPS NORTHWEST OF THE AREA. SEAS
WILL BUILD TO 5 TO 7 FEET BY THIS AFTERNOON. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR ALL COASTAL WATERS ZONES BEGINNING
AT 9 AM. A COLD FRONT WILL PUSH ACROSS THE COASTAL WATERS EARLY
WEDNESDAY WITH STRONG OFFSHORE WINDS DEVELOPING AND CONTINUING
THROUGH THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 76 53 64 37 57 / 50 20 10 10 10
KBPT 75 51 64 37 57 / 50 10 10 10 10
KAEX 74 48 57 31 53 / 70 30 10 10 10
KLFT 77 57 66 37 57 / 70 30 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR THE FOLLOWING ZONES: ACADIA...CALCASIEU...
CAMERON...IBERIA...JEFFERSON DAVIS...LAFAYETTE...LOWER ST.
MARTIN...ST. MARY...UPPER ST. MARTIN...VERMILION.
TX...LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR THE FOLLOWING ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT CST
TONIGHT FOR THE FOLLOWING ZONES: 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...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.
&&
$$
