FXUS64 KLCH 240255
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
855 PM CST WED DEC 23 2009
.DISCUSSION...
ZONES HAVE BEEN UPDATED TO REFLECT NEWLY ISSUED TORNADO WATCH #806
WHICH REPLACES WATCH #805 AS WELL AS ADDING COUNTIES/PARISHES
SOUTH OF THE OLD WATCH TO THE COAST. NEW WATCH IS VALID UNTIL
1200Z/0600CST.
AS FAR AS THE FORECAST ALL PREVIOUS THINKING CONTINUES TO HOLD
TRUE THIS EVENING SO NO CHANGES WERE MADE TO THE GRIDS/ZONES OTHER
THAN TO AMEND THE WATCH INFO.
25
&&
.PREV DISCUSSION... /ISSUED 513 PM CST WED DEC 23 2009/
DISCUSSION...
AN ACTIVE COLD FRONT WILL ADVANCE INTO SOUTHEAST TEXAS JUST
BEFORE DAWN THURSDAY...EXITING SOUTH CENTRAL LOUISIANA BY LATE
MORNING THURSDAY. A PRE-FRONTAL WARM SECTOR WEDGE WILL BE IN PLACE
ACROSS THE WESTERN UPPER GULF COAST STATES. NUMEROUS FRONTAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED...SEVERE WEATHER INCLUDING
TORNADOES IS POSSIBLE.
WEATHER WILL BE COMING TO AND END WITH PASSAGE OF FRONT.
PREV DISCUSSION... /ISSUED 452 PM CST WED DEC 23 2009/
DISCUSSION...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO
DEVELOP OVER THE AREA IN ADVANCE OF A VERY ENERGETIC SYSTEM OVER
THE CENTRAL/SOUTHERN PLAINS. THIS ACTIVITY SHOULD CONTINUE THROUGH
THE EVENING/OVERNIGHT HOURS...WITH COVERAGE AND INTENSITY
INCREASING OVER EAST TEXAS AFTER MIDNIGHT.
ACTIVITY STILL FORECAST TO CONGEAL INTO A QLCS /SQUALL LINE/ AS
COLD FRONT TRAILING FROM DEEPENING SFC LOW LIFTING TOWARD THE RED
RIVER VALLEY ENTERS EAST TEXAS...AND THE FORCING BECOMES MORE
LINEAR. ATMOSPHERIC PARAMETERS CONTINUE TO SUPPORT THE FULL
SPECTRUM OF SEVERE WEATHER MODES...WITH KINEMATIC PROFILES
CONTINUING TO LOOK QUITE IMPRESSIVE.
IMPRESSIVE LOW LEVEL WINDS /40-50KT AT H925/ HAVE PROMPTED THE
ISSUANCE OF A LAKE WIND ADVISORY TONIGHT AND THURSDAY FOR THE
COASTAL COUNTIES/PARISHES ALONG AND SOUTH OF I-10. WINDS ARE
EXPECTED TO DIMINISH A BIT THIS EVENING...BUT RAMP UP AGAIN AFTER
MIDNIGHT INTO THURSDAY MORNING AS THE LLJ INTENSIFIES AHEAD OF THE
FRONTAL BOUNDARY. WEST TO NORTHWEST WINDS BEHIND THE FRONT WILL
ALSO PUSH ADVISORY CRITERIA...SO STRETCHED THE END TIME OF THE
ADVISORY TO TOMORROW EVENING. THIS CAN ALWAYS BE TRUNCATED IF NEED
BE.
THE FRONT IS EXPECTED TO BE NEAR THE SABINE RIVER BY 6 AM...AND
QUICKLY PROGRESS EAST THROUGH THE REMAINDER OF LOUISIANA THROUGH
THE MORNING HOURS. GIVEN THE PROGGED SPEED OF THE SYSTEM...WIDESPREAD
HEAVY RAIN AND/OR FLOODING IS STILL NOT EXPECTED TO BE A MAJOR
PROBLEM...THOUGH LOCALLY HEAVY RAINFALL IS STILL POSSIBLE.
BY THURSDAY EVENING...RAINFALL WILL BE WELL EAST OF THE AREA...AND
THE SKY WILL BE IN THE PROCESS OF CLEARING.
MUCH COOLER AND DRIER AIR WILL SPILL INTO THE AREA BEHIND THE
FRONT...MAKING FOR A CHILLY BY RAIN-FREE CHRISTMAS WEEKEND.
GLOBAL MODELS STILL FLOPPING A BIT ON A SYSTEM PROGGED TO AFFECT
THE AREA EARLY NEXT WEEK. THE LAST TWO RUNS OF THE ECMWF HAVE
GAINED A BIT OF RUN-TO-RUN CONSISTENCY...SO A BLEND OF THESE
SOLUTIONS WERE USED FOR THE DAY 7 TO 8 FORECAST.
MARINE...
A TIGHTENING PRESSURE GRADIENT BETWEEN HIGH PRESSURE TO THE EAST
AND A DEVELOPING LOW OVER THE SOUTHERN PLAINS WILL BRING
STRONG SOUTHERLY WINDS AND ROUGH SEAS OVER THE NORTHWEST GULF TONIGHT
INTO THURSDAY MORNING. A COLD FRONT WITH SHOWERS AND THUNDERSTORMS
WILL ADVANCE ACROSS THE GULF WATERS THURSDAY MORNING WITH A STRONG
OFFSHORE FLOW DEVELOPING IN ITS WAKE AND SEAS HEIGHTS INCREASING.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 62 63 34 51 33 / 90 90 10 10 10
KBPT 57 58 32 51 34 / 90 70 10 10 10
KAEX 62 62 32 49 29 / 100 100 10 10 10
KLFT 63 65 36 51 33 / 80 100 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...LAKE WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST THURSDAY
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 MIDNIGHT TONIGHT TO 6 PM CST THURSDAY
FOR THE FOLLOWING ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST FRIDAY 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.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST FRIDAY
FOR THE FOLLOWING ZONES: CALCASIEU LAKE...SABINE LAKE...
VERMILION BAY.
&&
$$
