FXUS64 KLCH 221223
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
623 AM CST TUE DEC 22 2009
.AVIATION...
CLOUDS TO THE WEST WILL GRADUALLY SPILL INTO SE TX AND SRN LA TDY
ALTHOUGH VFR CONDITIONS WILL HOLD. WINDS WILL BE ON THE INCREASE
AHEAD OF THE NEXT FRONT.
&&
.PREV DISCUSSION... /ISSUED 353 AM CST TUE DEC 22 2009/
DISCUSSION...SATELLITE IMAGERY DEPICTING SOME STRATOCU OVER THE
FORECAST AREA AT 5-6K FT. LIMITED FOG DEVELOPMENT THIS MORNING
WITH OUR SURFACE HIGH NOW EAST OF THE REGION. PRONOUNCED
TEMPERATURE GRADIENT NOTED AT THIS TIME RANGING FROM THE UPPER 30S
OVER THE NORTHEAST PORTION OF THE AREA TO LOWER 50S SOUTHWEST.
RATHER PLEASANT DAY AHEAD AS STRENGTHENING AND DEEPENING
SOUTHERLIES COME IN FROM THE GULF WATERS. EXPECTING TEMPERATURES
SEVERAL DEGREES ABOVE THAT OF MONDAY DESPITE SOME INCREASED CLOUD
COVER...AND OVERALL WILL BE SEEING TEMPS AROUND 8 DEGREES ABOVE THE
SEASONAL NORM. COULD NOT RULE OUT A FEW SHOWERS PRIMARILY OVER
THE NORTH TO WEST SECTIONS OF THE REGION BUT MOST WILL MAKE IT
THROUGH THE DAY WITHOUT SEEING ANY RAINS. FAIR WEATHER BREAKS DOWN
FOR WEDNESDAY...AND EVEN MORE SO MOVING THROUGH WEDNESDAY NIGHT INTO
THURSDAY.
ECMWF AND GFS CONTINUE IN RELATIVE GOOD AGREEMENT IN REGARD TO
OUR MID-WEEK WEATHER MAKER WITH ADDED SUPPORT FROM THE NAM. NEXT
MID/UPPER SYSTEM NOW ENTERING THE NORTHWEST CONUS AND PROGGED TO DROP
RAPIDLY SOUTHEAST INTO THE LOWER PLAINS WEDNESDAY...THEN SLOWING
AND MOVING NORTHEAST THROUGH THE REMAINDER OF THE WEEK. EVOLVING
THEN DEEPENING SURFACE LOW ANTICIPATED THROUGH THIS TIME PERIOD.
STRENGTHENING LOW LEVEL SOUTHERLIES AND ACCOMPANYING EXPANSIVE
LOW LEVEL JET OF 30 TO 40 KNOTS EXPECTED WEDNESDAY USHERING IN
DESTABILIZING GULF MOISTURE. AT THIS TIME CARRYING HIGH END CHANCE
TO LIKELY POPS THROUGH THE DAY. BETTER CHANCES APPEAR LATE WEDNESDAY
NIGHT AND THURSDAY MORNING ALONG OR JUST AHEAD OF ASSOCIATED
SURFACE FRONT AS DEEPENING SURFACE LOW ADVANCES FROM OKLAHOMA INTO
MISSOURI. MODELS SHOWING STRONG LOW LEVEL CONVERGENCE AT 1000-850
MB AND EXPECTING SQUALL LINE DEVELOPMENT IN THIS AREA.
SQUALL LINE SHOULD BE ADVANCING RAPIDLY EAST OUT OF SOUTHEAST
TEXAS MOVING ACROSS THE SABINE RIVER SHORTLY BEFORE SUNRISE
THURSDAY THEN EXITTING THE AREA EARLY THURSDAY AFTERNOON.
KINEMATICS CONTINUE TO LOOK IMPRESSIVE WITH AS POST-FRONTAL LLJ
INCREASING TO 50 KNOTS PLUS WHILE UPPER LEVEL JET OF 100 KNOTS
PLUS WITHIN INCREASINGLY NEGATIVELY TILTED TROF ADVANCES OVER THE
AREA WITH MODELS SUGGESTING A STRONG DIVERGENT CORE. WITH ALL THIS
SAID WILL BE MAINTAINING OUR SEVERE THREAT...WHILE SPC CONTINUES A
SLIGHT RISK WHICH HAS NOW BEEN EXPENDED EAST COVERING THE WHOLE
AREA.
REMAINDER OF THE WEEK LOOKING DRY AND COOLER AS HIGH PRESSURE
BECOMES REESTABLISHED. HAVE GONE AHEAD AND INTRODUCED A CHANCE FOR
SHOWERS MONDAY AND TUESDAY WITH OUR LONG TERM MODELS HINTING AT
YET ANOTHER ROUND OF CYCLOGENESIS OVER THE NEAR COASTAL WATERS
DURING THIS TIME FRAME.
MARINE... A TIGHTENING PRESSURE GRADIENT BETWEEN HIGH PRESSURE
TO THE EAST AND A DEVELOPING LOW OVER THE SOUTHERN PLAINS WILL BRING
STRENGTHENING WINDS AND BUILDING SEAS OVER THE NORTHWEST GULF
TODAY AND WEDNESDAY. A COLD FRONT WITH SHOWERS AND THUNDERSTORMS
WILL ADVANCE ACROSS THE GULF WATERS THURSDAY MORNING WITH A STRONG
OFFSHORE FLOW DEVELOPING IN ITS WAKE.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 70 59 72 57 61 / 20 40 60 70 70
KBPT 70 61 72 54 62 / 30 40 60 60 50
KAEX 68 56 69 56 59 / 20 50 70 80 70
KLFT 70 57 73 61 65 / 10 40 50 60 70
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO NOON CST THURSDAY
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...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.
&&
$$
