785
FXUS64 KLCH 210558
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1158 PM CST FRI NOV 20 2009
AVIATION
SFC LOW NOW APPEARS TO BE CENTERED OFF THE TX COAST...ABOUT 60 NM
SOUTHEAST OF MATAGORDA BAY...IN THE VICINITY OF STRONGER
CONVECTION IN THE WESTERN GULF. LOW IS STILL EXPECTED TO TRACK
ACRS THE NW GULF...TOWARD SOUTHERN OR SOUTHEASTERN LA...REMAINING
SOUTH OF OUR TAF SITES. RADAR CURRENTLY SHOWS JUST PATCHY LIGHT
RAIN OVER LA AND SE TX WITH AN AREA OF HEAVIER RAIN OFFSHORE.
EXPECT RAINFALL TO INCREASE IN AREA TONIGHT OVER SOUTHERN TAF
SITES AS THE LOW MOVES CLOSER TO THE COAST...WITH HEAVIEST
RAINFALL TO REMAIN OFFSHORE. CIGS AND VISBYS ALSO EXPECTED TO
LOWER TO MVFR TONIGHT AS RAIN AREA INCREASES. IN
ADDITION...NORTHEAST WINDS ARE EXPECTED TO STRENGTHEN TO BETWEEN
10-15 KT TONIGHT...GRADUALLY SHIFTING TO THE NORTH BY MIDDAY
SATURDAY AT KBPT AND KLCH...AND MID AFTERNOON AT KAEX...KLFT AND
KARA. CONDITIONS SHOULD BEGIN TO IMPROVE LATE SATURDAY AS THE LOW
SYSTEM MOVES NORTHEAST OF THE AREA. 24
PREV DISCUSSION
/ISSUED 921 PM CST FRI NOV 20 2009/
DISCUSSION...
LATEST SFC ANALYSIS SHOWS A BROAD AREA OF LOW PRESSURE OFF THE
MIDDLE TX COAST WHILE WATER VAPOR IMAGERY SHOWS SHORTWAVE TROF
CROSSING CNTL TEXAS. WEAK VORTS ROUNDING THE SHORTWAVE EVIDENT IN
CLUSTERS OF RAIN...ONE CURRENTLY MOVING OUT OF S-CNTL LA AND INTO
SERN LA WITH ANOTHER LARGER AREA MOVING ALONG THE UPPER TX COAST
TOWARD SERN TEXAS. YET ANOTHER ROUND OF RAIN SHOWING UP OVER CNTL
TX NEAR THE MAIN SHORTWAVE TROF. SOME CONVECTION NOTED WITHIN THE
RAIN SHIELD OVER THE NWRN GULF IN VICINITY OF THE SFC LOW.
MAIN CHANGE TO THE FORECAST TONIGHT IS TO REMOVE MENTION OF
THUNDER OVER MOST OF THE FORECAST AREA AS CONDITIONS LOOK TOO
STABLE. HOWEVER LEFT MENTION OF ISOLATED THUNDER OVER THE SERN
ZONES AS STORMS OFFSHORE COULD MOVE ASHORE INTO THIS REGION LATER
TONIGHT GIVEN CURRENT AND FORECAST TRAJECTORIES. OTHERWISE GOING
FORECASTS LOOK GOOD WITH RAIN A GOOD BET OVERNIGHT. TEMPS/WINDS
LOOK FINE AS IS AND NO CHANGES PLANNED THERE.
UPDATE OUT SHORTLY.
25
PREV DISCUSSION... /ISSUED 553 PM CST FRI NOV 20 2009/
AVIATION...
AN AREA OF LIGHT RAIN WAS MOVING EAST ACRS SRN LA...MAINLY
AFFECTING SERN TAF SITES. WILL SEE A BREAK EARLY THIS EVENING WITH
THE NEXT ROUND OF LIGHT RAIN EXPECTED TO MOVE INTO THE NW GULF AND
ACRS SRN AREAS LATE THIS EVENING INTO THE OVERNIGHT HOURS. THIS
RAINFALL IS THE RESULT OF AN UPPER LEVEL TROUGH AND ASSOCIATED SFC
LOW NEAR THE TX COAST THAT WILL LIFT NE ACRS THE AREA TONIGHT INTO
EARLY SATURDAY. EXPECT PERIODS OF MAINLY LIGHT RAIN BEGINNING
AROUND 02Z AT KBPT...WITH RAINFALL PROGRESSING EAST ACRS KLCH AND
INTO KLFT AND KARA FROM 03Z-06Z. VFR CIGS AND VISBYS EXPECTED AT
KAEX. VFR ALSO EXPECTED AT KLFT AND KARA THROUGH LATE
TONIGHT...BECOMING MVFR BETWEEN 10Z-12Z...WHILE GENERALLY MVFR
CONDITIONS TO PREVAIL THROUGHOUT THE PERIOD AT KLCH AND KBPT.
IN ADDITION...AS THE SFC LOW DEVELOPS AND MOVES TOWARD THE AREA
TONIGHT...A TIGHTENING GRADIENT WILL PRODUCE BREEZY NORTHEASTERLY
WINDS WITH POSSIBLE GUSTS BETWEEN 20 AND 25 KTS OVERNIGHT INTO
EARLY SATURDAY MAINLY FOR SRN TAF SITES. 24
PREV DISCUSSION... /ISSUED 435 PM CST FRI NOV 20 2009/
DISCUSSION...RATHER CHALLENGING FORECAST AND HENCE RUNNING A
LITTLE LATE. WAS HOPING FOR BETTER CONTINUITY BETWEEN MODELS...PARTICULARLY
THE EMCWF AND GFS...BUT THIS DID NOT OCCUR. HAVE TRENDED TOWARD
THE GFS SOLUTION WHICH WAS OFFERED SOME SUPPORT BY THE LOCAL WRF
MODEL AS WELL AS HPC. THUS A MORE PROGRESSIVE AND SHORTER-LIVED EVENT
THAN ADVERTISED BY THE EUROPEAN MODEL.
RADAR SHOWING LIGHT TO MODERATE RAINS OVER SOUTH LOUISIANA
ADVANCING EAST. EXPECTING SECONDARY BATCH OF RAINS TO ADVANCE
ACROSS THE AREA OVERNIGHT SO CARRYING CATEGORICAL POPS
SOUTH...LIKELY NORTH. PRIMARILY LOOKING AT OVER-RUNNING RAINS AND
ANY LIGHTNING ACTIVITY TO BE BE MINIMAL AT MOST. RAINS AMOUNTS OF
1 TO 2 INCHES EXPECTED ALONG THE INTERSTATE 10 CORRIDOR SOUTH...AND
LESSER AMOUNTS FURTHER NORTH.
RAINS TAPER OFF SATURDAY WITH SYSTEM ADVANCING EAST. REMAINDER OF
WEEKEND LOOKING DRY AND COOL WITH A NORTHERLY FLOW REMAINING IN
PLACE. NEXT POTENTIAL FROPA AND RAIN-MAKER COMING TUESDAY.
MARINE...LOW PRESSURE DEEPENING AND MOVING ACROSS THE NORTHWEST GULF WILL
BRING STRENGTHENING WINDS AND BUILDING SEAS TONIGHT. WIDESPREAD
RAIN WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL DIMINISH
SATURDAY AS THE SYSTEM EXITS EAST.
PRELIMINARY POINT TEMPS/POPS
KLCH 50 63 46 71 / 80 40 10 10
KBPT 51 65 46 71 / 60 30 10 10
KAEX 50 62 43 68 / 60 40 10 10
KLFT 52 60 47 67 / 80 50 10 10
LCH WATCHES/WARNINGS/ADVISORIES
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM CST SATURDAY FOR 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-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.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR 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-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 CALCASIEU LAKE-
SABINE LAKE-VERMILION BAY.
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