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

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089
FXUS64 KLIX 260053
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
653 PM CST WED FEB 25 2015

.SOUNDING DISCUSSION...

FLIGHT WENT A LITTLE QUICKER THAN NORMAL TONIGHT. SOUNDING WAS
SATURATED FROM THE SURFACE THROUGH 740 MB...AND THEN DRIED
RAPIDLY. DRYING OCCURRED BEFORE BALLOON REACHED THE FREEZING
LEVEL...SO THE ANTICIPATED ICING POTENTIAL FAILED TO DEVELOP.
FREEZING LEVEL WAS AT 11.8K FEET WITH -20C AT 22K FEET. A 6C
INVERSION EXISTS BETWEEN 975 AND 850 MB.

WINDS THROUGHOUT THE SOUNDING WERE RATHER STRONG. A LIGHT NORTH
WIND AT THE SURFACE INCREASED TO 20 KNOTS BY 1500 FEET AND BECAME
WEST AT 50 KNOTS AROUND 6000 FEET. WINDS REMAINED WEST-SOUTHWEST
THROUGH 100 MB WITH A PEAK WIND OF 152 KNOTS AT 39.3K FEET.

FLIGHT TERMINATED A COUPLE MILES NORTHWEST OF MOBILE REGIONAL
AIRPORT OVER BIG CREEK LAKE ALABAMA AT ABOUT 99K FEET OR 18.75
MILES. 35

&&

.PREV DISCUSSION... /ISSUED 425 PM CST WED FEB 25 2015/

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...

FAST MOVING SHORTWAVE TROUGH OVER THE LOWER MISSISSIPPI VALLEY AND
THE ASSOCIATED SURFACE LOW OVER THE NORTH CENTRAL GULF COAST COASTAL
WATERS WILL QUICKLY MOVE EAST OF THE FORECAST AREA DURING THE
REMAINDER OF THIS AFTERNOON AND EARLY THIS EVENING. THE DRY SLOT HAS
ALREADY ACCELERATED EAST THROUGH MOST OF THE WESTERN HALF...AND THE
REMAINING AREAS SHOULD SEE THE BULK OF THE RAIN END BY 5 OR 6 PM.
SOME BREAKS IN CLOUD COVER ARE POSSIBLE TONIGHT...AND ALONG WITH
COLD AIR ADVECTION AND NORTH WINDS THIS SHOULD PUSH THE LOW
TEMPERATURES DOWN CLOSE TO THE MOS NUMBERS WHICH ARE IN THE LOWER TO
MID 30S. THE LARGE POLAR SURFACE HIGH PRESSURE RIDGE...CENTERED OVER
THE NORTHERN PLAINS IS EXPECTED TO MOVE SOUTHEAST AND REINFORCE
THE COLDER AIR OVER THE CENTRAL GULF COAST REGION THURSDAY THROUGH
FRIDAY NIGHT. THIS WILL RESULT IN DRY CONDITIONS...HOWEVER SKIES
SHOULD REMAIN PARTLY TO MOSTLY CLOUDY DUE TO CONTINUED CYCLONIC FLOW
IN THE MID/UPPER LEVELS AND SOME LINGERING MOISTURE LAYERS. THE
PRESENCE OF SNOW COVER UNUSUALLY CLOSE TO OUR NORTH MEANS
TEMPERATURES SHOULD NOT BE ANY WARMER THAN THE SUITE OF MOS GUIDANCE
OVER THE NEXT COUPLE DAYS. THIS MEANS HIGHS WILL STRUGGLE TO REACH
50 DEGREES AND THE LOWS WILL CONTINUE TO BE RATHER COLD FOR LATE
FEBRUARY...MOSTLY IN THE LOWER TO MID 30S.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...

A LARGE SURFACE HIGH PRESSURE RIDGE IS EXPECTED TO COVER MOST OF THE
EASTERN HALF OF THE CONUS OVER THE WEEKEND. AFTER FLATTENING
OUT/BECOMING MORE ZONAL ON FRIDAY...THE MID/UPPER LEVEL FLOW PATTERN
WILL AMPLIFY AGAIN OVER THE WEEKEND AS A DIGGING TROUGH DIVES SOUTH
NEAR THE CALIFORNIA COAST TOWARDS BAJA. THIS WILL RESULT IN
SOUTHWEST FLOW ALOFT OVER THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY. THE HIGH PRESSURE RIDGE SHOULD KEEP OUR AREA DRY FRIDAY INTO
SATURDAY HOWEVER...MINOR DISTURBANCES IN THE SOUTHWEST FLOW AND
INCREASING MOISTURE OFF THE GULF WILL BRING RAIN CHANCES SUNDAY INTO
THE EARLY PART OF NEXT WEEK. THERE ARE NO STRONG SYSTEMS TO IMPACT
THE AREA OR PUSH ANOTHER COLD FRONT THROUGH...SO A WARMING TREND
WILL FINALLY PUSH TEMPERATURES ABOVE NORMAL STARTING SUNDAY AND
CONTINUING INTO NEXT WEEK. RAIN CHANCES WILL BE HARD TO TIME AND
WILL BE FINE TUNED OVER THE NEXT SEVERAL DAYS...BUT THERE SHOULD BE
SUFFICIENT INSTABILITY FOR SOME CHANCE OF THUNDERSTORMS STARTING
SUNDAY.  22/TD

AVIATION...

AN IFR DECK OF STRATUS RANGING FROM 500 TO 800 FEET WILL REMAIN OVER
THE TERMINALS THROUGH 00Z AS A LOW PRESSURE SYSTEM SLIDES THROUGH
THE NORTHERN GULF OF MEXICO.  AS THE LOW PULLS TO THE
EAST...INCREASING SUBSIDENCE AND DRY AIR ADVECTION THIS EVENING WILL
ALLOW CONDITIONS TO IMPROVE TO MVFR FROM WEST TO EAST.  PREVAILING
MVFR CONDITIONS ARE EXPECTED BY MID-MORNING THURSDAY. 32

MARINE...

THE DEPARTING LOW PRESSURE AREA TO THE EAST WILL CONTINUE TO HAVE A
STRONG PRESSURE GRADIENT ON THE WEST SIDE PRODUCING NORTHWEST TO
NORTH WINDS OVER 20 KNOTS UNTIL LATE EVENING OR MIDNIGHT. WILL
CONTINUE THE SMALL CRAFT ADVISORY FOR THESE WINDS UNTIL
MIDNIGHT...AND HAVE EXTENDED THE ADVISORY UNTIL 3 AM OVER MOST OF
THE OFFSHORE WATERS DUE TO LINGERING 7 FOOT SEAS THAT ARE EXPECTED.
THE CENTER OF A NARROW SURFACE RIDGE WILL SETTLE NEAR THE REGION
LATE TONIGHT RESULTING IN A BRIEF LULL IN THE STRONGER WINDS AND
HIGHER SEAS. A REINFORCEMENT OF COOLER AIR AND HIGH PRESSURE WILL
THEN BUILD SOUTH THURSDAY INTO FRIDAY...AND WILL KEEP NORTH TO
NORTHEAST WINDS ON THE STRONGER SIDE THURSDAY NIGHT THROUGH SATURDAY
NIGHT. WINDS WILL TURN BACK AROUND TO SOUTHEAST BUT REMAIN MODERATE
TO STRONG ON SUNDAY. 22/TD

DECISION SUPPORT...

DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT

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  31  48  31  47 /  10   0  10  10
BTR  32  51  31  49 /  10   0  10  10
ASD  33  51  31  51 /  10   0  10   0
MSY  37  51  37  50 /  10   0  10   0
GPT  34  51  33  51 /  20   0  10   0
PQL  33  50  31  52 /  20   0  10   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT THURSDAY 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 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...AND COASTAL WATERS FROM THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

     SMALL CRAFT ADVISORY UNTIL 3 AM THURSDAY FOR THE FOLLOWING
     ZONES: COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA
     FROM 20 TO 60 NM...COASTAL WATERS FROM STAKE ISLAND LA TO
     THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60
     NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO 60 NM.

MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT THURSDAY 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 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...AND COASTAL WATERS FROM THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

     SMALL CRAFT ADVISORY UNTIL 3 AM THURSDAY FOR THE FOLLOWING
     ZONES: COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA
     FROM 20 TO 60 NM...COASTAL WATERS FROM STAKE ISLAND LA TO
     THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60
     NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO 60 NM.

&&

$$







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