FXUS64 KLCH 260351
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
951 PM CST FRI DEC 25 2009
.DISCUSSION...
PRIMARY CHANGE TO GRIDS/ZONES THIS EVENING IS CLOUD COVER AS
SATELLITE IMAGERY SHOWS PLENTY OF HIGH CLOUDS STREAMING THIS WAY
IN THE SUBTROPICAL JET. CIRRUS SHOULD GRADUALLY THICKEN OVERNIGHT.
BIG QUESTION IS HOW MUCH THE HIGH CLOUDINESS WILL IMPACT OVERNIGHT
TEMPS ALTHOUGH THE CIRRUS SHOULD REMAIN RATHER THIN FOR AWHILE. AS
TEMPS ARE FALLING ABOUT AS FORECAST FEEL TEMPS SHOULD REACH MINS
BEFORE THE CIRRUS HAS ITS GREATEST IMPACT. HOWEVER BASED ON LATEST
OBS THE MINS OVER LOWER ACADIANA MAY BE A BIT ON THE LOW SIDE BUT
WILL NOT ADJUST FOR NOW.
UPDATE OUT SHORTLY.
25
&&
.PREV DISCUSSION... /ISSUED 342 PM CST FRI DEC 25 2009/
DISCUSSION...
A VERY COOL AND DRY AIRMASS HAS SETTLED OVER THE FORECAST AREA
THIS CHRISTMAS DAY. AIRMASS DID NOT MODIFY MUCH AS DECENT SNOW
PACK NOTED ON VISIBLE SATELLITE PICTURE OVER NORTHERN TEXAS AND
OKLAHOMA. DEW POINTS ARE CURRENTLY IN THE UPPER TEENS TO MID 20S.
WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...AS SURFACE RIDGE SETTLES
IN...EXPECT GOOD RADIATIONAL COOLING WHICH WILL PROVIDE QUITE COLD
TEMPERATURES. ALMOST THE ENTIRE FORECAST AREA WILL SEE FREEZING
TEMPERATURES...WITH SOME OF THE COLDER SPOTS OF THE NORTHERN ZONES
IN THE MID 20S...CLOSE TO THE RE-ISSUANCE OF FREEZE WARNING PER
LOCAL POLICY. THANKS TO HOUSTON WEATHER FOR COORDINATION ON THIS.
SHORT WAVE IN THE SOUTHERN STREAM IS EXPECTED TO QUICKLY MOVE FROM
THE BAJA INTO THE WESTERN GULF BY TOMORROW...WHICH IN TURN WILL
CAUSE A SURFACE LOW TO DEVELOP OFF THE LOWER TEXAS COAST. THIS LOW
AND UPPER LEVEL DISTURBANCE WILL MOVE QUICKLY ACROSS THE REGION ON
SATURDAY NIGHT. SURFACE LOW STAYS BEYOND THE COASTAL WATERS AND
MOISTURE WITH THIS FEATURE NOT AS IMPRESSIVE WITH PAST
SYSTEMS...AS PWAT INCREASES TO ONLY BETWEEN 0.75 TO 1 INCH AND
MEAN RH MAINLY BELOW 60 PERCENT...WITH MOST OF THE BEST MOISTURE
CONFINED TO THE COAST. THERMAL PROFILES (1000-850 THICKNESS
GREATER THAN 1310M AND SURFACE WET BULBS ABOVE 32F) ALSO SHOW THAT
LIGHT PRECIP SHOULD ALL FALL IN THE FORM OF LIGHT RAIN.
SOUTHERN STREAM REMAINS ACTIVE WITH ANOTHER IMPRESSIVE SHORT WAVE
MOVING ACROSS THE REGION IN THE TUESDAY-WEDNESDAY TIME FRAME.
MOISTURE PROFILES HIGHER WITH THIS SYSTEM AS PWAT PROGGED TO BE
AROUND 1.25 INCHES AND MEAN RH OVER 80 PERCENT. SURFACE LOW WITH
THIS SYSTEM STAYS OFFSHORE...SO AGAIN MAINLY ISENTROPIC OVER-
RUNNING RAINS WILL BE IN STORE.
CANADIAN COLD FRONT QUICKLY MOVES DOWN BEHIND THIS SYSTEM ON NEW
YEARS EVE...BRINGING A COLD NEW YEARS DAY.
RUA
MARINE...
NORTHERLY WINDS HAVE INDEED DECREASED THIS AFTERNOON AS SURFACE
RIDGE SETTLES OVER THE REGION. WINDS WILL BECOME MORE EASTERLY AND
INCREASE ON SATURDAY NIGHT AS A SURFACE LOW DEVELOPS OFF THE TEXAS
COAST AND MOVES ACROSS THE COASTAL WATERS. NORTHERLY WINDS ON THE
BACK-SIDE OF THE LOW WILL BE CLOSE TO SMALL CRAFT ADVISORY
CRITERIA LATE SATURDAY NIGHT INTO SUNDAY.
RUA
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 30 57 40 58 33 / 0 10 30 10 0
KBPT 30 58 39 57 34 / 0 20 30 10 0
KAEX 27 56 34 54 30 / 0 10 20 10 0
KLFT 30 56 40 58 34 / 0 10 30 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
