FXUS64 KLCH 040519
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1119 PM CST THU DEC 3 2009
.AVIATION...
FOR THE 04/06Z TAF ISSUANCE...
IN THE SHORT TERM...VFR CONDITIONS ARE EXPECTED THROUGH THE NIGHT INTO
FRIDAY MORNING MAINLY HIGH LEVEL MOISTURE CONTINUES TO MOVE ACROSS
THE REGION.
STILL LOOKS LIKE SOME WINTER TYPE PRECIPITATION WILL BE MOVING
ACROSS THE FORECAST AREA LATE FRIDAY INTO FRIDAY EVENING. UPPER
LEVEL DISTURBANCE WILL BE MOVING ACROSS IN THE ACTIVE JET STREAM
ALOFT. MEANWHILE...A SURFACE LOW WILL DEVELOP AND MOVE ACROSS THE
NORTHERN GULF. THESE FEATURES WILL COMBINE TO BRING MOISTURE AND
LIFT ACROSS THE REGION. MEANWHILE...A HIGH PRESSURE SYSTEM OVER
THE ROCKIES WILL CONTINUE TO BUILD INTO THE AREA BRINGING COLDER
AIR IN.
THE RESULT WILL BE LIGHT RAIN TO BEGIN AT KBPT AFTER 04/18Z WITH
MVFR CEILINGS. THESE CONDITIONS WILL GRADUALLY MOVE EASTWARD
ACROSS THE REMAINDER OF THE TAF SITES BY 04/21Z. BY 21Z...EXPECT
AIR COLUMN TO BE COLD ENOUGH...AS FREEZING LEVELS GOES BELOW 1000
FEET AND CLOSER TO 600 FEET...FOR LIGHT SNOW TO BEGIN TO MIX IN AT
KAEX AND KBPT TAF SITES. KLCH AND KLFT SHOULD BEGIN TO SEE SNOW
MIX IN AFTER 05/00Z WITH PRECIPITATION AT THAT TIME CHANGING OVER
TO ALL SNOW AT KAEX. WILL KEEP KARA WITH JUST RAIN AT THIS TIME
THROUGHOUT THE FORECAST AS PROJECTED FREEZING LEVELS STAY JUST
ABOVE 1000 FEET.
RUA
&&
.PREV DISCUSSION... /ISSUED 1028 PM CST THU DEC 3 2009/
UPDATE...
STILL LOOKING LIKE A HISTORIC EARLY SNOW EVENT WILL TAKE PLACE
FRIDAY AFTERNOON AND EVENING ACROSS MOST OF SE TX/C AND S LA.
LATEST GUIDANCE STILL CONFIDENT THE RAIN WILL BE CHANGING OVER
TO A RAIN/SNOW MIXTURE BY EARLY AFTERNOON FRIDAY OVER SE TX...AND
THEN CHANGING OVER TO ALL SNOW BY LATE FRIDAY AFTERNOON AND
EVENING ACROSS THE REMAINDER OF WESTERN AND CENTRAL LOUISIANA
NORTH OF THE I-10 CORRIDOR. ACCUMULATIONS OF 1.5 TO 2 INCHES ARE
LIKELY...WITH LOCALIZED AMOUNTS UP TO 3 INCHES POSSIBLE. LOCAL
CRITERIA STATES A WINTER STORM WARNING IS REQUIRED FOR SNOWFALL
OF 2 OR MORE INCHES WITHIN 12 HOURS...THUS IS NOW ISSUED.
ALONG THE I-10 CORRIDOR AND FURTHER SOUTH...THE RAIN WILL LIKELY
CHANGE OVER TO A RAIN/SNOW MIX BY LATE AFTERNOON...THEN CHANGE
OVER TO ALL SNOW AFTER SUNSET...EXCEPT THE IMMEDIATE COASTAL AREAS
WHERE A RAIN/SNOW MIX WILL LIKELY PERSIST. SNOWFALL ACCUMULATIONS
OF UP TO AN INCH ARE LIKELY...WITH LOCALIZED AMOUNTS UP TO 2
INCHES POSSIBLE IN A FEW AREA JUST NORTH OF I-10. THUS A WINTER
WEATHER ADVISORY IS ISSUED.
DML/JR
MARINE...
UPDATED THE MARINE HAZARDS TO INCLUDE SCA CONDITIONS STARTING AT 3
AM FRI...LASTING THRU 18Z SAT. LEFT THE GALE WATCH ALONE FROM 21Z
FRI TO 06Z SAT...AS LATEST NAM/GFS GUIDANCE STILL KEEPS WINDS IN
THE 25-28KT RANGE DURING THIS PERIOD...WITH GUSTS TO GALE FORCE.
DML
PREV DISCUSSION... /ISSUED 416 PM CST THU DEC 3 2009/
DISCUSSION...
LATEST SFC ANALYSIS SHOWS HIGH PRESSURE CENTERED OVER HIGH PLAINS
RIDGING SEWD ACROSS THE AREA. VAPOR IMAGERY SHOWS TROFFING
STRETCHING FROM HUDSON BAY TO THE DESERT SW. COLD AIR STRATOCU HAS
DEVELOPED FARTHER WEST THIS AFTERNOON WITH BKN CEILINGS REPORTED
AT MOST LOCATIONS TODAY. MEANWHILE ADDITIONAL CLOUD COVER SHOWING
UP SATELLITE IMAGERY ADVANCING EWD OVER THE LONE STAR STATE.
VARIABLES COMING TOGETHER FOR AN EARLY SNOW EVENT ACROSS SERN
TX/SWRN LA...ESPECIALLY N OF THE I-10 CORRIDOR...BEGINNING JUST
BEFORE SUNSET TOMORROW AND LASTING THROUGH THE NIGHT. SHORTWAVE
CURRENTLY OVER THE 4-CORNERS REGION IS PROGGED TO PUSH EWD TOWARD
SRN PLAINS. SYSTEM WILL HELP INDUCE SFC LOW OFF THE LOWER TX COAST
WHICH WILL THEN CROSS THE CNTL/NRN GULF. COMBO OF THESE FEATURES
WILL PRODUCE WIDESPREAD RAIN BEGINNING TOMORROW MORNING OVER SERN
TX THEN SPREADING EWD DURING THE DAY. COLD AIR PULLED SWD BY THE
LOW WILL COOL THE ATMOSPHERIC COLUMN WITH MODEL SOUNDINGS SHOWING
ENTIRE COLUMN BELOW FREEZING BY 00Z/SAT AT KJAS...ALL BUT LOWEST
COUPLE HUNDRED FEET AT KAEX...AND LESS THAN A THOUSAND FOOT WARM
LAYER AT REMAINING STATIONS. THEREFORE EXPECTING THE RAIN TO
CHANGEOVER TO SNOW BY SUNSET ACROSS THE LAKES REGION...AND ON
ACROSS THE REMAINDER OF INTERIOR SERN TEXAS AND CNTL LA AFTER
SUNSET. CLOSER TO THE COAST MODEL SOUNDINGS CONTINUE TO SHOW A
LITTLE BIT OF A WARM LAYER REMAINING FROM KLCH EWD...THEREFORE
COULD SEE A LITTLE BIT OF A RAIN/SNOW MIX OVERNIGHT. EVENT SHOULD
COME TO AN END BEGINNING AROUND MIDNIGHT FOR THE FAR WRN AREAS...
TO AROUND SUNRISE SATURDAY NEAR THE ATCHAFALAYA BASIN.
DUE TO THE UNCERTAINTIES SHOWN IN THE LATEST SUITE OF COMPUTER
MODELS WILL NOT UPGRADE INHERITED WINTER WEATHER WATCH ATTM.
ACCUMULATIONS RIGHT NOW LOOK TO REMAIN BELOW WARNING CRITERIA AND
WOULD EXPECT A WINTER WEATHER ADVISORY TO BE ISSUED LATER TONIGHT.
HOWEVER WOULD NOT BE SURPRISED EITHER IF THE NEXT SUITE COMES INTO
BETTER AGREEMENT ON LOCATION AND AMOUNTS WHICH WOULD PUSH OUR
EXPECTED ACCUMULATIONS ABOVE THE TWO-INCH THRESHOLD.
FREEZE WATCHES/WARNINGS ARE EXPECTED FOR FRIDAY NIGHT AS MINS ARE
FORECAST TO FALL TO THE MID/UPPER 20S ACROSS MOST OF THE AREA
NORTH OF I-10. APPARENT TEMPS WILL BE IN THE LOWER 20S BY SUNRISE
SATURDAY AS NRLY WINDS BEHIND THE LOW PERSIST.
REMAINDER OF THE FORECAST REMAINS BASICALLY UNCHANGED WITH DRIER
AND COLD CONDITIONS SATURDAY. COASTAL TROF DEVELOPS BY SUNDAY WITH
ANOTHER AREA OF LOW PRESSURE DEVELOPING AND PULLS NEWD INTO THE
SERN ZONES. ANOTHER FRONT PROGGED TO CROSS THE AREA ON TUESDAY
WITH DRY WEATHER ON TAP FOR THE REMAINDER OF THE PERIOD.
MARINE...
LATEST FORECAST SHOWS WINDS OVER THE SERN MARINE ZONES GETTING TO
THE CUSP OF GALE FORCE TOMORROW AFTERNOON. FOR NOW WILL JUST LET
THE GALE WATCH RIDE AND ALLOW LATER SHIFTS TO BETTER REFINE GALE
THREAT OVER THE COASTAL WATERS. REGARDLESS SCA CONDITIONS EXPECTED
TOMORROW AND LASTING INTO SATURDAY MORNING. HIGH PRESSURE WILL
PROVIDE QUICK SHOT OF LIGHTER WINDS BEFORE STRONG ONSHORE FLOW
DEVELOPS AHEAD OF THE NEXT COASTAL LOW ON SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 39 44 30 49 35 / 10 70 80 10 10
KBPT 40 43 30 50 37 / 10 80 70 10 10
KAEX 35 43 27 48 30 / 10 60 80 10 10
KLFT 39 46 30 48 33 / 10 60 80 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WINTER STORM WARNING FROM 6 PM FRIDAY TO 9 AM CST SATURDAY FOR
THE FOLLOWING ZONES: ALLEN...AVOYELLES...BEAUREGARD...
EVANGELINE...RAPIDES...ST. LANDRY...VERNON.
WINTER WEATHER ADVISORY FROM 6 PM FRIDAY TO 9 AM CST SATURDAY
FOR THE FOLLOWING ZONES: ACADIA...CALCASIEU...CAMERON...
IBERIA...JEFFERSON DAVIS...LAFAYETTE...LOWER ST. MARTIN...
ST. MARY...UPPER ST. MARTIN...VERMILION.
TX...WINTER WEATHER ADVISORY FROM 6 PM FRIDAY TO 9 AM CST SATURDAY
FOR THE FOLLOWING ZONES: JEFFERSON...ORANGE.
WINTER STORM WARNING FROM NOON FRIDAY TO 9 AM CST SATURDAY FOR
THE FOLLOWING ZONES: HARDIN...JASPER...NEWTON...TYLER.
GM...GALE WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING 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.
SMALL CRAFT ADVISORY FROM 3 AM TO 3 PM CST FRIDAY 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.
SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY NIGHT TO NOON CST
SATURDAY 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.
SMALL CRAFT ADVISORY FROM 3 AM FRIDAY TO NOON CST SATURDAY 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.
&&
$$
