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

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245
FXUS64 KLIX 250052
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
652 PM CST MON NOV 24 2014

...SOUNDING DISCUSSION...

DRIER AIR HAS BEEN MOVING INTO SOUTHEAST LOUISIANA AND SOUTHWEST
MISSISSIPPI TODAY IN THE WAKE OF A COLD FRONT THAT HAS PUSHED
THROUGH OUR AREA. THE PRECIPITABLE WATER VALUE HAS DROPPED FROM
0.91 INCHES THIS MORNING TO 0.63 INCHES THIS EVENING. THERE IS AN
ELEVATED TEMPERATURE INVERSION BETWEEN 2600 AND 4600 FEET AND A
FEW OTHER MUCH SMALLER INVERSIONS ABOVE THIS INVERSION.
OVERALL...TEMPERATURES ARE LOWER /COOLER/ AT ANY GIVEN LEVEL
THAN 24 HOURS AGO. THE WIND PROFILE IS TYPICAL OF A POST-FRONTAL
ATMOSPHERE WITH BACKING WINDS. WINDS FROM THE SURFACE TO 2500 FEET
WERE FROM THE NORTH BETWEEN 15 AND 20 KNOTS. THEN WINDS SHIFTED
AND WERE FROM THE SOUTHWEST FROM 5000 FEET TO THE TROPOPAUSE. A
PEAK WIND SPEED OF 129 KNOTS WAS LOCATED AT 33500 FEET.

00Z BALLOON INFO: NO ISSUES WITH THE FLIGHT THIS EVENING. THE
BALLOON ATTAINED A HEIGHT OF 19.7 MILES ABOVE THE GROUND BEFORE
BURSTING NEAR TIBBIE AL 118 MILES DOWNRANGE. THE BALLOON WAS IN
FLIGHT 102 MINUTES.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 402 PM CST MON NOV 24 2014/

SHORT TERM...
COLD FRONT PASSED OFFSHORE EARLIER THIS MORNING BUT TEMPS HAVE STILL
BEEN ABLE TO MAX OUT IN THE MID 60S TO MID 70S. DEWPOINTS PAID NO
ATTENTION AND HAVE BEEN FALLING ALL DAY LONG. ALTHOUGH LOWS WILL BE
MUCH COOLER TONIGHT THAN LAST NIGHT...THEY MAY NOT BE AS COLD AS
PREVIOUSLY FORECASTED. VISIBLE SATELLITE SHOWS A STREAM OF CIRRUS
CLOUDS MOVING IN FROM THE SW OVER CENTRAL PORTIONS OF LA AS WELL AS
THICKER MID/HIGH LEVEL CLOUDS OVER THE NORTHERN GULF OF MEXICO
SLIGHTLY EXPANDING NORTH INTO THE CWA. THIS WILL BE ONE FACTOR TO
LIMIT OVERNIGHT COOLING SOMEWHAT. THE OTHER IS WIND. THE CENTER OF
THE HIGH PRESSURE BEHIND THE FRONT WILL STILL BE OVER EASTERN TEXAS
AND OKLAHOMA BY 12Z TUESDAY AND THUS STILL HAVE A DECENT PRESSURE
GRADIENT OVER THE CWA. THIS WILL KEEP WINDS ELEVATED OVERNIGHT AND
IN THE 5-10 MPH RANGE. JUST DONT SEE TEMPERATURES FALLING OVERLY LOW
IN A LIGHT BREEZE AND SLIGHTLY CLOUDY REGIME. SO HAVE BROUGHT UP
FORECAST LOWS BY 3 TO 5 DEGREES AREAWIDE AND THAT MAY NOT BE ENOUGH.

A WEAKER SHORTWAVE IN THE UPPER LEVELS WILL SWING ALONG THE BASE OF
THE TROUGH AND THROUGH THE AREA TUESDAY. THIS WILL DRAW THE FRONTAL
BOUNDARY STALLED OVER THE GULF OF MEXICO BACK NORTH TOWARDS OUR CWA.
HOW FAR NORTH REMAINS TO BE SEEN AND CRUCIAL TO HOW FAR INLAND
SHOWERS ASSOCIATED WITH THE BOUNDARY MEET. LATEST GUIDANCE SHOWS
THIS TO BE SLIGHTLY LESS INLAND THAN PREVIOUS RUNS SO HAVE TRIMMED
THE WESTERN EDGE OF THIS PRECIP TO EAST OF A SLIDELL TO HOUMA LINE.
TIME FRAME OF SHOWERS LOOK TO BE TUESDAY AFTERNOON THRU MIDNIGHT...
OR UNTIL THE TROUGH FINALLY KICKS THE BOUNDARY EAST AND INTO THE
ATLANTIC OCEAN.

LONG TERM...
QUITE TRANQUIL CONDITIONS EXPECTED FOR THE REMAINDER OF THE WEEK AS
THE AREA WILL BE UNDER GENERAL NORTHWEST FLOW IN THE UPPER LEVELS
AND DOMINATED BY SURFACE RIDGE CENTERED TO THE NORTH. THIS PATTERN
WILL KEEP COOLER THAN NORMAL TEMPERATURES IN PLACE. ONCE THIS RIDGE
SLIDES EAST THIS WEEKEND...SOUTHERLY FLOW WILL RETURN AND PICK
MOISTURE BACK UP OVER THE AREA. COULD SEE A FEW SHOWERS RETURN LATE
IN THE WEEKEND OR EARLY NEXT WEEK.

MEFFER

AVIATION...

ANTICIPATE VFR CONDITIONS THROUGH THE FORECAST PERIOD. CIRRUS WILL
CONTINUE TO MOVE ACROSS THE AREA OVERNIGHT INTO TUESDAY. ANOTHER
IMPULSE LIFTING THROUGH THE BASE OF THE UPPER TROF WILL SPREAD MID
LEVEL CLOUDS ACROSS THE FAR EASTERN SECTIONS TOMORROW...AND
PROBABLY ONLY AFFECT KGPT. WIND WILL BE THE MAIN FORECAST CONCERN
DOWNWIND OF LAKE PONTCHARTRAIN LATE TONIGHT AND TUESDAY WITH 15 TO
20 KNOT WINDS EXPECTED. 35

MARINE...

COLDER AND DRIER AIR WILL REACH THE COASTAL WATERS THIS EVENING AND
WILL HOIST EXERCISE CAUTION FLAGS FOR THE TIDAL LAKES AND
MISSISSIPPI SOUND...AND SMALL CRAFT ADVISORY ELSEWHERE THROUGH
TUESDAY. WOULDNT BE SURPRISED TO SEE A FEW SPOTS ON THE LAKES GET
CLOSE TO ADVISORY LEVEL CONDITIONS. ADVISORY MAY NEED TO BE
LENGTHENED ON THE BACK END INTO TUESDAY NIGHT...AT LEAST OVER THE
OPEN WATERS. ANOTHER REINFORCING SHOT OF COOL AIR EXPECTED TO
INCREASE WINDS AGAIN WEDNESDAY NIGHT AND THURSDAY...BUT COLD
ADVECTION NOT QUITE AS STRONG WITH THAT ONE. ONSHORE FLOW AROUND 10
KNOTS EXPECTED FOR MUCH OF THE WEEKEND. 35

DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
             SMALL CRAFT ADVISORIES BEGIN TONIGHT

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  41  58  36  64 /  10  10  10   0
BTR  42  59  37  65 /  10  10  10   0
ASD  43  61  37  63 /  10  10  10   0
MSY  48  60  42  63 /  10  10  10   0
GPT  44  60  39  61 /  10  20  30   0
PQL  42  61  38  61 /  10  30  30  10

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY FROM 9 PM MONDAY TO 6 PM TUESDAY FOR THE
     FOLLOWING ZONES: BRETON SOUND...CHANDELEUR SOUND...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...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM PORT FOURCHON
     TO LOWER ATCHAFALAYA RIVER OUT 20 NM...COASTAL WATERS FROM
     STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO
     60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

MS...NONE.
GM...SMALL CRAFT ADVISORY FROM 9 PM MONDAY TO 6 PM TUESDAY FOR THE
     FOLLOWING ZONES: BRETON SOUND...CHANDELEUR SOUND...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...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM PORT FOURCHON
     TO LOWER ATCHAFALAYA RIVER OUT 20 NM...COASTAL WATERS FROM
     STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO
     60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

&&

$$







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