FXUS64 KLIX 231003
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
403 AM CST WED DEC 23 2009

.SYNOPSIS...
MAIN SURFACE LOW IS LOCATED NEAR THE FOUR CORNERS REGION WITH COLD
FRONT EXTENDING SWWD ACROSS THE BAJA OF CA AND STATIONARY FRONT
EWD ACROSS THE TX PANHANDLE AND CENTRAL OK. A SECONDARY AND WEAKER
LOW EXISTS IN CENTRAL OK WITH WARM FRONT THROUGH NRN AR AND MS.
MOIST TONGUE IS EVIDENT IN EASTERN TX WITH TD/S IN THE MID 60S
BACKED UP TO DRYLINE IN WEST TX. LOCALLY...DEWPOINTS AND TEMPS
HAVE BEEN STEADILY RISING WITH WAA ONGOING. MAJORITY OF HEAVIER
RAIN ACROSS THE STATE HAS BEEN OCCURRING IN REGION OF GREATER
DIFFLUENCE AS SEEN ON 500MB WIND FIELD. UPPER LOW CONTINUES TO DIG
SEWD ACROSS THE WESTERN CONUS. A QUITE POTENT 300MB JET OF 175KTS
IS STREAKING ACROSS NRN MEXICO. WV IMAGERY INDICATES A DRY LAYER
IS SURGING EWD OVER TEXAS ON THE LEFT EXIT REGION OF THIS JET. 

&&

.SHORT TERM...
WARM AND MOIST AIR WILL CONTINUE TO FILTER INTO THE AREA TODAY AS
A STEADY 12 TO 15 MPH SERLY WIND DEVELOPS FROM INCREASING PGF
BETWEEN STATIONARY SFC RIDGE TO THE EAST AND APPROACHING SFC
TROUGH. HIGHS SHOULD BE A DEGREE OR TWO WARMER THAN YESTERDAY WITH
ABOUT TWO THIRDS OF THE CWA AT OR ABOVE 70. TOOK A COMPROMISE ON
POPS BETWEEN THE WETTER MAV AND DRIER MET. ENDED UP WITH SLIGHT
CHANCE FOR EASTERN AREAS AND CHANCE SH/TS IN EXTREME WESTERN
ZONES.  

COLD FRONT WILL BEGIN MAKING MORE SUBSTANTIAL PROGRESS ACROSS TX
LATER TONIGHT. RAIN CHANCES WILL BE INCREASING MORESO AFTER
MIDNIGHT. AT THIS TIME...THE AREA WILL BE IN THE WARM SECTOR EAST
OF COLD FRONT AND SOUTH OF WARM FRONT. LOW LEVEL JET LOOKS TO
INCREASE MOST AROUND SUNRISE ON CHRISTMAS EVE IN WESTERN PORTIONS
OF THE CWA WITH 50+KTS A FEW KFT OFF THE SFC AND STILL A SLIGHT
DIRECTIONAL SHEAR. MIXING DOWN THESE WINDS WILL POSE THE THREAT
FOR DAMAGING WINDS ALONG AN ONGOING SQUALL LINE. SRH OF AROUND
400 M2/S2 WILL BE THE PEAK IN THIS EARLY TO MID MORNING TIME OVER
THE WEST. SO...ISOLATED TORNADO THREAT WILL EXIST. MODELS ARE IN
GOOD AGREEMENT THAT THE FRONT/SQUALL LINE WILL IN INTO COASTAL MS
COUNTIES BY LATE AFTN AND THE EXIT THE CWA DURING THE EVENING HRS.
TOTAL QPF THROUGH THIS RAIN PERIOD SHOULD BE IN THE 1 TO 2 INCH
RANGE. 

.LONG TERM...
UPPER LEVEL LOW WILL SOMEWHAT STALL ACROSS THE CENTRAL CONUS THIS
WEEKEND. THIS WILL KEEP THE AREA IN NWRLY SFC FLOW REGIME AND THUS
TEMPS WILL STAY BELOW NORMAL. KEPT WITH MUCH OF PREVIOUS FORECAST
HIGHS IN THE LOWER 50S AND 3OS FOR THE LOWS. GFS AND ECMWF HAVE
SIGNIFICANTLY SLOWED THE TIMING OF A SFC LOW TO MOVE ACROSS THE
AREA NEXT WEEK FROM MON TO LATE WED.

MEFFER
&&

.AVIATION...
VFR MID LEVEL CEILINGS AND VSBY EXPECTED THROUGH ABOUT MID-MORNING 
WITH PROGRESSIVELY LOWERING CEILINGS TO LOW END VFR THIS AFTERNOON. 
WIDESPREAD MVFR CEILINGS IN WEST LOUISIANA INTO TEXAS WILL BE MOVING 
INTO AREA BY THIS EVENING AND ACCOMPANIED WITH A FEW MARINE LAYER 
SHOWERS OVERNIGHT. PRE-FRONTAL LINEAR MCS SQUALL LIKELY TO DEVELOP 
AND MOVE INTO KBTR TERMINAL SPACE AROUND 15Z THURSDAY...KMCB AROUND 
16Z...KMSY 17Z AND KGPT AROUND 19Z BUT WITH A WEAKENING TREND 
FARTHER EAST. GFS BUFR SOUNDINGS RUN IN CHAP PROGRAM SHOWS MOST 
UNSTABLE CONDITIONS AROUND THE 15Z TIME STEP WITH WINDS SWINGING 
FROM SOUTHERLY TO WESTERLY WITH THE PASSAGE OF SQUALL LINE.  24/RR

&&

.MARINE...
ONSHORE FLOW STEADILY INCREASING AS GRADIENT TIGHTENS WITH MATURING 
LOW PRESSURE SYSTEM MOVING INTO TEXAS FROM NEW MEXICO. VERY STRONG 
UPPER LEVEL JET STREAM WITH VALUES 150KT OR HIGHER TO LIKELY INDUCE 
A PRE-FRONTAL SQUALL LINE THAT MOVES ACROSS THE COASTAL WATERS 
THURSDAY MORNING INTO THE EARLY AFTERNOON HOURS. GIVEN THE DEGREE OF 
JET SUPPORT AND DRY AIR IN THE MID AND UPPER LEVELS...SQUALL GUSTS 
MAY EXCEED 50KT WITH THE PASSAGE OF THIS FEATURE. THEREAFTER...THE 
FRONT MOVES THROUGH THE COASTAL WATERS THURSDAY EVENING WITH COLD 
HIGH PRESSURE BUILDING INTO THE GULF WITH SEVERAL RE-ENFORCEMENTS 
THROUGH THE WEEKEND. WINDS AND SEAS WILL BECOME QUITE HAZARDOUS 
BEGINNING LATER TODAY AND CONTINUING FOR THE WEEKEND BEFORE SETTLING 
DOWN EARLY TO MID NEXT WEEK. 24/RR

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  68  58  61  34 /  30  90 100  20 
BTR  73  59  61  36 /  30  90 100  10 
MSY  72  61  69  42 /  20  80 100  10 
GPT  68  59  66  41 /  30  70 100  30 

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY FROM MIDNIGHT THURSDAY TO 6 AM FRIDAY FOR 
     THE FOLLOWING ZONES: COASTAL WATERS FROM PASCAGOULA MS TO 
     THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 
     NM...COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST 
     PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS 
     FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER 
     ATCHAFALAYA RIVER LA FROM 20 TO 60 NM...AND COASTAL WATERS 
     FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER 
     ATCHAFALAYA RIVER LA OUT 20 NM. 

     SMALL CRAFT ADVISORY FROM 6 AM THURSDAY TO 6 AM FRIDAY FOR THE 
     FOLLOWING ZONES: AND LAKE PONTCHARTRAIN AND LAKE MAUREPAS. 

MS...NONE.
GM...SMALL CRAFT ADVISORY FROM 6 AM THURSDAY TO 6 AM FRIDAY FOR THE 
     FOLLOWING ZONES: AND LAKE PONTCHARTRAIN AND LAKE MAUREPAS. 

     SMALL CRAFT ADVISORY FROM MIDNIGHT THURSDAY TO 6 AM FRIDAY FOR 
     THE FOLLOWING ZONES: COASTAL WATERS FROM PASCAGOULA MS TO 
     THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 
     NM...COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST 
     PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS 
     FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER 
     ATCHAFALAYA RIVER LA FROM 20 TO 60 NM...AND COASTAL WATERS 
     FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER 
     ATCHAFALAYA RIVER LA OUT 20 NM. 

&&

$$