FXUS64 KLIX 042356
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
556 PM CST THU DEC 4 2008

.AVIATION / 00Z TAFS /...

AT 00Z THE CLEARING LINE WAS APPROACHING MCB AND BTR...BOTH ARE
EXPECTED TO SCATTER OUT BY 02Z. THE CLEARING LINE IS EXPECTED TO
REACH MSY AND GPT BY 05-06Z. WINDS SHOULD REMAIN UP TONIGHT...AND
POSSIBLY BE A GUSTY AT MSY OVERNIGHT. VFR CONDITIONS ARE EXPECTED
FRIDAY AT ALL FOUR TAF SITES. 25

&

.PREV DISCUSSION... /ISSUED 328 PM CST THU DEC 4 2008/

SYNOPSIS...
THE COLD FRONT HAS MOVED THROUGH THE MAJORITY OF THE AREA AND
TEMPERATURES HAVE BEEN FALLING THROUGHOUT THE AFTERNOON AS
FORECAST. ONLY ISOLATED SHOWERS REMAIN OVER THE COASTAL WATERS
EAST OF THE MISSISSIPPI RIVER. THICK CLOUDS STILL COVERING THE
AREA...BUT THE CLEARING LINE IS STARTING TO APPROACH THE
NORTHWEST PORTION OF THE AREA.

SHORT TERM...
SKIES SHOULD BEGIN TO CLEAR THIS EVENING AND WILL CONTINUE TO
CLEAR OVERNIGHT TONIGHT AS HIGH PRESSURE BUILDS INTO THE AREA.
WITH GUIDANCE PRETTY TIGHTLY CLUSTERED THROUGH THE SHORT
TERM...DIDN/T SEE A REASON TO STRAY VERY FAR FROM THE TEMPS
FORECAST IN THE MODELS. GENERALLY EXPECTING MID TO UPPER 30S
ACROSS THE NORTHERN HALF OF THE AREA AND LOW 40S ACROSS THE
SOUTHERN HALF TONIGHT. TEMPS SHOULD REBOUND INTO THE MID 50S
DURING THE AFTERNOON HOURS FRIDAY.

A SECOND UPPER TROUGH WILL MOVE THROUGH THE REGION SATURDAY
EVENING PUSHING A REINFORCING HIGH INTO THE AREA WHICH WILL KEEP
COOL AND DRY WEATHER IN THE FORECAST THROUGH THE WEEKEND.

LONG TERM...
MODELS BEGIN TO DIVERGE SIGNIFICANTLY MONDAY. THE GFS AND ECMWF
CONTINUE TO FLIP FLOP WITH EACH OTHER ALMOST EVERY MODEL RUN.
GIVEN THE UNCERTAINTY...HAVE MADE FEW CHANGES TO THE EXTENDED
PERIOD AS THE INHERITED FORECAST APPEARS TO BE IN FAIRLY GOOD
AGREEMENT WITH THE HPC PROGS AND IS A CLOSE MATCH TO THE GFS.

AS A SURFACE LOW DEVELOPS OVER EASTERN OKLAHOMA...A WARM FRONT IS
EXPECTED TO LIFT THROUGH THE REGION MONDAY EVENING AND INTO MONDAY
NIGHT. HAVE INCREASED POPS INTO THE CHANCE CATEGORY FOR THIS TIME
PERIOD AND WILL INDICATE THUNDER ALONG AND THE EXPECTED FRONTAL
BOUNDARY.

BY TUESDAY...THE SOUTHERLY FLOW IS EXPECTED TO INCREASE AS A LOW
LEVEL JET TAKES STRENGTHENS OVER THE REGION. THIS SHOULD LEAD TO
AN INFLUX OF VERY MOIST AND UNSTABLE AIR INTO THE REGION...WHICH
IS EXPECTED TO BE SMACK DAB IN THE MIDDLE OF THE WARM SECTOR BY
THIS TIME. WILL CARRY HIGH END CHANCE POPS FOR TUESDAY...BUT WILL
NEED TO WATCH FUTURE MODEL RUNS AS THE FORECASTS EVOLVE AND GET A
BETTER HANDLE ON THE SITUATION. THE WAY THE GFS FORECAST STANDS
NOW...MODERATE INSTABILITY SHOULD BE IN PLACE WITH LI VALUES OF -2
TO -5 AND CAPE VALUES IN THE 500 TO 1200 J/KG RANGE ACROSS MUCH OF
THE AREA. HOWEVER...WITH PRETTY GOOD CLOUD COVER IN PLACE...THE
MAIN QUESTION WILL BE WHETHER WE GET ENOUGH HEATING TO DESTABILIZE
AT THE SURFACE. ALL IN ALL IT LOOKS TO BE A VERY DYNAMIC SYSTEM
AT THIS TIME AND WE WILL CERTAINLY BE WATCHING IT AS THE MODEL
FORECASTS EVOLVE OVER THE NEXT FEW DAYS.

THE COLD FRONT IS CURRENTLY FORECAST TO CLEAR THE AREA TUESDAY
NIGHT WITH HIGH PRESSURE BUILDING INTO THE AREA FOR THE SECOND
HALF OF THE WEEK.

MARINE... MODERATE NORTH WINDS ARE EXPECTED TONIGHT AND TAPERING
OFF FRIDAY LATE MORNING AND 1000 TO 700MB THICKNESS LAYERS WILL
DROP 30M OVERNIGHT AND CAA WILL BECOME NEUTRAL FRIDAY THROUGH
EARLY SATURDAY. ANOTHER COLD FRONT WILL PUSH THROUGH THE AREA
SATURDAY NIGHT. THE MAIN TROUGH WILL REMAIN ACROSS THE EAST CONUS
MAINTAIN NORTHWEST FLOW ACROSS THE MARINE AREA SATURDAY AND
SATURDAY NIGHT. FINALLY...A VERY DYNAMIC SYSTEM WILL MOVE EAST
ACROSS THE LOWER MISSISSIPPI VALLEY LATE TUESDAY NIGHT...PRODUCING
A STRONG LOW LEVEL JET ACROSS THE EXTREME NORTH GULF MONDAY NIGHT
INTO TUESDAY. STRONG WINDS ARE EXPECTED TO BEHIND THE FRONTAL
PASSAGE TUESDAY NIGHT AND STRONG WINDS POSSIBLY CONTINUING THROUGH
NEXT THURSDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 33 53 29 58 / 0 0 10 10
BTR 36 55 31 58 / 0 0 10 10
MSY 42 56 38 59 / 0 0 10 10
GPT 37 56 33 57 / 0 0 10 10

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 AM CST FRIDAY FOR GMZ530-550-555-
570-575.

MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 AM CST FRIDAY FOR GMZ550-555-570-
575.

&&

$$




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