Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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724
FXUS64 KLIX 181830 AAA
AFDLIX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
130 PM CDT FRI APR 18 2014

.AVIATION...
CONDITIONS WILL TREND FROM A MIX OF MVFR TO VFR CATEGORY CIGS TO
MOSTLY VFR AS THE AFTERNOON PROGRESSES...THEN NEARLY COMPLETE
CLEARING IS EXPECTED THIS EVENING. SOME PATCHY LIGHT FOG MAY
IMPACT KMCB AND POSSIBLY ANOTHER AIRPORT OR TWO LATE TONIGHT/EARLY
SATURDAY MORNING. THE MAIN FORECAST UNCERTAINTY IS THE THREAT OF
ISOLATED TO LOCALLY SCATTERED TSRA DEVELOPING IN THE CORRIDOR FROM
KAEX- KMCB- KHDC- KMSY-KHUM-KPTN-KAEX DURING THE 19-22Z PERIOD AS
THE MAIN SHORTWAVE TROUGH AXIS AND COLD POOL AT 500 MB MOVE
THROUGH THE REGION. HAVE NOT INCLUDED ANY TSRA IN THE TAFS AT THIS
TIME...BUT WILL CONTINUE TO MONITOR SATELLITE AND RADAR TRENDS AND
UPDATE AS NECESSARY. 22/TD

&&

.MARINE...
EXPANDED/EXTENDED THE SMALL CRAFT ADVISORY /SCA/ AMD SMALL CRAFT
EXERCISE CAUTIN HEADLINES WITH THE LATE MORNING ISSUANCE TO
ACCOUNT FOR OBSERVATIONAL AND MODEL TRENDS. WINDS AS HIGH AS 30
KNOTS WITH GUSTS OVER GALE FORCE WERE OCCURRING OVER THE FAR
EASTERN WATERS...BUT THESE CONDITIONS WERE REMAINING JUST BELOW
GALE WARNING CRITERIA. WINDS SHOULD BE EASING LATER THIS AFTERNOON
OR EVENING AS THE LOW PRESSURE SYTEM OVER THE NORTHEAST GULF OF
MEXICO MOVES AWAY FROM THE REGION. 22/TD

&&

.PREV DISCUSSION... /ISSUED 333 AM CDT FRI APR 18 2014/

SYNOPSIS...
SURFACE LOW PRESSURE IS CENTERED OVER THE NORTHERN GULF WITH A
WARM FRONT EXTENDING FROM THE LOW EASTWARD THROUGH THE CENTRAL
FLORIDA PENINSULA AND A COLD FRONT EXTENDING FROM THE LOW
SOUTHWESTWARD TOWARD THE BAY OF CAMPECHE. A RATHER LARGE
PRECIPITATION SHIELD IS LOCATED TO THE NORTH AND EAST OF THE
SURFACE LOW.

LOCALLY...MOST RAIN HAS MOVED AWAY FROM THE AREA...BUT A FEW
SHOWERS STILL IMPACTING THE MS COASTAL COUNTIES. TEMPERATURES
GENERALLY SITTING IN THE 60 TO 65 DEGREE RANGE WITH DEWPOINTS
RUNNING IN THE MID TO UPPER 50S.

DISCUSSION...
THE SURFACE LOW OVER THE GULF SHOULD CONTINUE TO LIFT TO THE
NORTHEAST TODAY IN RESPONSE TO A FAST MOVING SHORT WAVE. LATEST
MODEL RUNS ARE INDICATING A GREATER POSSIBILITY OF ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AS THE MID
LEVEL TROUGH AXIS TRAVERSES THE REGION. GFS IS MOST AGGRESSIVE
WITH ITS QPF FIELD WHILE THE NAM CONTAINS THE DRIEST SOLUTION. THE
EURO IS SOMEWHERE IN BETWEEN...THOUGH CLOSER TO THE GFS THAN THE
NAM. INSTABILITY WILL BE FAIRLY LIMITED WITH MODEL SOUNDINGS
INDICATING ONLY MEAGER CAPE VALUES IN THE 200 TO 600 J/KG RANGE.
NONETHELESS WITH PLENTY OF MOISTURE IN PLACE AND THE ADDED LIFT
ASSOCIATED WITH THE SHORT WAVE...HAVE GONE AHEAD AND BUMPED POPS
UP INTO THE SLIGHT CHANCE OR LOW END CHANCE CATEGORY FOR THIS
AFTERNOON AND WILL MENTION A SLIGHT CHANCE OF THUNDER. COVERAGE
SHOULD BE PRETTY SPOTTY...WITH QPF GENERALLY LESS THAN ONE QUARTER
INCH...THOUGH ISOLATED AMOUNTS NEAR OR ABOVE ONE HALF INCH COULD
BE POSSIBLE.

SHORT WAVE EXITS THE AREA DURING THE LATE AFTERNOON...AND THIS
SHOULD PUT AN END TO ANY PRECIP ACROSS THE REGION AS HIGH PRESSURE
BUILDS INTO THE AREA. WITH DEEP RIDGING FORECAST TO DOMINATE THE
AREA OVER THE WEEKEND...EXPECT WARM/SEASONAL CONDITIONS WITH NO
REAL CHANCE OF PRECIP. AFTERNOON TEMPS SHOULD TOP OUT IN THE UPPER
70S AND LOWER 80S...AND SUBSIDENCE ALOFT SHOULD KEEP SKIES MOSTLY
CLEAR TO PARTLY CLOUDY.

RIDGING WILL MAINTAIN CONTROL OF THE AREA ON MONDAY...BUT WILL
BEGIN TO BREAK DOWN AS ANOTHER UPPER TROUGH MOVES INTO THE
MISSISSIPPI VALLEY. THIS TROUGH IS EXPECTED TO SEND A WEAK COLD
FRONT TOWARD THE AREA TUESDAY...BRINGING WITH IT THE NEXT CHANCE
OF RAIN. THE WEAK FRONT WILL BE DISSIPATING AS IT APPROACHES THE
AREA AND IT REMAINS TO BE SEEN HOW MUCH SHOWER AND THUNDERSTORM
ACTIVITY WILL REMAIN ON ITS SOUTHERN END. THAT SAID...AM CARRYING
HIGHER POPS...IN THE CHANCE CATEGORY...ACROSS NORTHERN ZONES
COMPARED TO SOUTHERN ZONES WHERE SLIGHT CHANCE POPS ARE INDICATED.
AS THE UPPER TROUGH FLATTENS OUT AND SLIDES EASTWARD...THE
WEAKENING FRONT WILL CONTINUE TO DISSIPATE NEAR THE COAST AND DEEP
RIDGING WILL ONCE AGAIN BUILD INTO THE AREA DURING THE WEDNESDAY
AND THURSDAY TIME FRAME.

AVIATION...
MAINLY MVFR CEILINGS THIS MORNING WILL GIVE WAY TO VFR CONDITIONS
THIS AFTERNOON. THE VFR CONDITIONS WILL THEN PERSIST THROUGH
TONIGHT AND EARLY SATURDAY MORNING. SOME LIGHT RAIN MAY IMPACT THE
KGPT...KASD...KMCB...KMSY AND KNEW TERMINALS THIS MORNING...MAINLY
EARLY. OTHERWISE...DRY CONDITIONS WILL PREVAIL DURING THE TAF
FORECAST PERIOD.

MARINE...
STRONG NORTHEAST TO NORTH WINDS AND ELEVATED SEAS WILL CONTINUE
TODAY ACROSS THE COASTAL WATERS AS AN AREA OF LOW PRESSURE OVER THE
NORTH CENTRAL GULF THIS MORNING TRACKS NORTHEAST TOWARD THE FLORIDA
PANHANDLE DURING THE DAY. THE WINDS WILL BE STRONGEST ACROSS THE
EASTERN GULF COASTAL WATERS AND GRADUALLY DIMINISH TONIGHT AND EARLY
SATURDAY FROM WEST TO EAST. SMALL CRAFT ADVISORIES AND EXERCISE
CAUTION  HEADLINES WILL BE IN EFFECT FOR MOST OF THE COASTAL
WATERS THIS MORNING...THEN GRADUALLY BE CUT BACK FROM WEST TO EAST
THIS AFTERNOON AND TONIGHT. A RIDGE OF HIGH PRESSURE WILL REBUILD
OVER THE AREA DURING THE WEEKEND WITH OFFSHORE FLOW SATURDAY
BECOMING ONSHORE DURING THE DAY SUNDAY AND PERSISTING INTO EARLY
NEXT WEEK. A WEAKENING COLD FRONTAL BOUNDARY MAY APPROACH THE
COAST ON TUESDAY.

DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
             MONITORING RIVER FLOODING
             SMALL CRAFT ADVISORY

DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN  = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE   = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
         VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
         WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
         TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED    = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  73  52  77  54 /  30  10   0  10
BTR  76  55  80  56 /  30  10   0  10
ASD  73  53  77  53 /  30  10   0   0
MSY  74  57  75  59 /  30  10   0   0
GPT  69  54  77  57 /  30  10   0   0
PQL  69  51  76  51 /  40  10   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM SATURDAY FOR THE FOLLOWING
     ZONES: COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
     FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60
     NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA
     OUT 20 NM...AND COASTAL WATERS FROM STAKE ISLAND LA TO THE
     SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM.

     SMALL CRAFT ADVISORY UNTIL 10 PM FRIDAY FOR THE FOLLOWING ZONES:
     BRETON SOUND...CHANDELEUR SOUND...AND MISSISSIPPI SOUND.

MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 10 PM FRIDAY FOR THE FOLLOWING ZONES:
     BRETON SOUND...CHANDELEUR SOUND...AND MISSISSIPPI SOUND.

     SMALL CRAFT ADVISORY UNTIL 6 AM SATURDAY FOR THE FOLLOWING
     ZONES: COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
     FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60
     NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA
     OUT 20 NM...AND COASTAL WATERS FROM STAKE ISLAND LA TO THE
     SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM.

&&

$$







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