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

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289
FXUS64 KLIX 232237
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
437 PM CST MON FEB 23 2015

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...

FREEZING RAIN AND ICING ARE THE MAIN CONCERN TONIGHT INTO EARLY
TUESDAY MORNING ACROSS THE FAR NORTHWEST PORTION OF THE AREA...AND
A FREEZING RAIN ADVISORY IS IN EFFECT STARTING AT 9 PM TONIGHT FOR
AREAS NORTH OF A LINE ROUGHLY FROM NEW ROADS TO MCCOMB.

NUMEROUS FAST MOVING DISTURBANCES...MAINLY WIND MAXIMA IN THE
UPPER JET...ARE NOTED IN WATER VAPOR IMAGERY ACROSS THE SOUTHERN
TIER OF U.S. STATES. OVERALL...THE GFS AND ECMWF LOOK LIKE THEY
HAVE A DECENT HANDLE ON THE ENERGY THAT IS CURRENTLY PRODUCING ICE
AND SNOW OVER PORTIONS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY WITH THE NAM NOT QUITE HANDLING THE SITUATION AS WELL. THE
MAIN CONCERNS...WHICH ARE SIGNIFICANT...ARE A COUPLE DEGREES IN
LOW LEVEL TEMPERATURE AND THE AMOUNT OF QPF OVER THE COLDEST AREAS
OF THE NORTHWEST TONIGHT...NEAR AND NORTHWEST OF A LINE FROM NEW
ROADS TO MCCOMB. THE GFS IS COLDEST AND DRIEST...WHILE THE NAM AND
ECMWF ARE SLIGHTLY WARMER BUT WETTER. HAVE OPTED TO LEAN TOWARDS
THE WETTER SOLUTIONS WITH AN AVERAGING OF TEMPERATURES. AS NOTED
IN THE PREVIOUS DISCUSSION...THE HIGHER CONFIDENCE AREAS WITHIN
THE FREEZING RAIN ADVISORY AREA TO RECEIVE FREEZING RAIN ARE IN
AND AROUND WILKINSON COUNTY WHERE LOWS ARE FORECAST TO DROP TO
AROUND 30. CONFIDENCE IS LOWER NEAR AND SOUTH OF NEW ROADS AND
MCCOMB WHERE THE LOW TEMPERATURE IS FORECAST TO BE RIGHT AROUND
32. GROUND TEMPERATURES WILL LIKELY REMAIN TOO WARM FOR ICE TO
DEVELOP ON MOST SIDEWALKS AND ROADS...HOWEVER THE ELEVATED
STRUCTURES LIKE BRIDGES AND OVERPASSES COULD DEVELOP ICY SPOTS.
THE RAIN CHANCES WILL BE DECREASING LATE TONIGHT AND TUESDAY
MORNING...HOWEVER HAVE KEPT THE ADVISORY IN EFFECT UNTIL 9 AM
SINCE TEMPERATURES WILL LIKELY REMAIN NEAR OR SLIGHTLY BELOW
FREEZING UNTIL THEN.

ANY REMAINING LIGHT RAIN LATE TUESDAY MORNING SHOULD END BY EARLY
AFTERNOON...HOWEVER IT WILL REMAIN CLOUDY AND COLD WITH HIGHS
RANGING FROM THE MID 40S TO AROUND 50. THE DRY CONDITIONS ARE ONLY
EXPECTED TO PERSIST INTO TUESDAY EVENING BEFORE THE NEXT MORE
POTENT SHORTWAVE TROUGH MOVES QUICKLY ACROSS TEXAS LATE TUESDAY
NIGHT AND WEDNESDAY MORNING AND THE CENTRAL GULF COAST REGION
WEDNESDAY AFTERNOON AND EVENING. AN ASSOCIATED AREA OF LOW
PRESSURE IS EXPECTED TO DEVELOP OVER THE WESTERN/NORTHWESTERN GULF
OF MEXICO WEDNESDAY MORNING AND THIS LOW WILL STRENGTHEN A BIT AND
QUICKLY MOVE EAST-NORTHEAST ACROSS THE NORTH CENTRAL GULF OF
MEXICO DURING THE LATE MORNING AND AFTERNOON ON WEDNESDAY. THE
COLDEST TEMPERATURES AGAIN WILL BE OVER THE FAR NORTH...BUT RIGHT
NOW IT APPEARS THE COLDEST TEMPERATURES DURING PRECIPITATION WILL
BE IN THE MID 30S WITH AN ABOVE FREEZING LAYER UP TO 8K TO 11K
FEET. WIDESPREAD MODERATE TO LOCALLY HEAVY RAINFALL ARE EXPECTED
STARTING LATE TUESDAY NIGHT AND CONTINUING THROUGH MOST OF
WEDNESDAY BEFORE THE RAIN QUICKLY ENDS DURING THE MID TO LATE
AFTERNOON. MODEL SOUNDINGS SHOW DECENT ELEVATED CAPE/INSTABILITY
OVER THE SOUTHEAST HALF SO HAVE INCLUDED A SLIGHT CHANCE OF
THUNDERSTORMS IN AGREEMENT WITH THE SPC DAY THREE CONVECTIVE
OUTLOOK. WEDNESDAY NIGHT IS EXPECTED TO BE DRY BUT CLOUDY AND
COLD WITH LOWS DROPPING TO THE LOWER TO MID 30S.

.LONG TERM /THURSDAY THROUGH MONDAY/...

A LARGE SURFACE HIGH PRESSURE RIDGE IS EXPECTED TO COVER MOST OF
THE EASTERN HALF OF THE CONUS THURSDAY THROUGH SATURDAY WHICH
SHOULD KEEP MOST LAND AREAS DRY UNTIL MAYBE LATE SATURDAY.
TEMPERATURES ARE EXPECTED TO REMAIN WELL BELOW NORMAL THURSDAY
AND FRIDAY...RECOVERING A BIT BUT STILL ON THE COOL SIDE ON
SATURDAY. THE MODELS GENERALLY KEEP SOUTHWEST FLOW IN THE MID TO
UPPER LEVELS AS THE NEXT SHORTWAVE TROUGH OR SERIES OF
DISTURBANCES START TO ORGANIZE OVER THE AREA FROM BAJA/SOUTHWEST
U.S. TO THE SOUTHERN ROCKIES. RAIN CHANCES WILL RISE ON
SUNDAY...BUT THE MODELS ARE FOCUSING MORE ENERGY AND QPF ON
MONDAY...SO TIMING AND VALUE OF THE RAIN CHANCES ARE QUITE A BIT
UNCERTAIN AT THIS POINT. HAVE MAINTAINED MENTION OF THUNDERSTORMS
AND SHOWERS ON MONDAY. 22/TD

&&

AVIATION...

A LOW STRATUS DECK WILL REMAIN OVER THE AREA THROUGH THE ENTIRE
FORECAST PERIOD.  A MIX OF IFR AND MVFR CEILINGS WILL CONTINUE TO
IMPACT THE TERMINALS DURING THIS PERIOD.  SOME LIGHT RAIN WILL ALSO
BE POSSIBLE...THAT COULD PRODUCE MVFR VISIBILITY RESTRICTIONS.
THERE COULD BE SOME LIGHT FREEZING RAIN AT KMCB AROUND 12Z...BUT
HAVE NOT INCLUDED IN THE TAF DUE TO OVERALL LOW CHANCES OF RAIN. 32

MARINE...

SMALL CRAFT ADVISORY CONDITIONS PERSISTED OVER MUCH OF THE MARINE
AREA...HOWEVER IMPROVEMENT IS EXPECTED THIS EVENING AND ESPECIALLY
TOWARDS MIDNIGHT. HAVE KEPT THE SMALL CRAFT ADVISORY IN EFFECT FOR
MOST WATERS UNTIL MIDNIGHT SINCE FREQUENT GUSTS OVER 20 KNOTS WILL
BE POSSIBLE AT LEAST INTO EARLY EVENING. A PERIOD OF LIGHTER WINDS
ARE EXPECTED TUESDAY INTO TUESDAY NIGHT BEFORE WINDS AND SEAS RAMP
UP QUICKLY ON WEDNESDAY DUE TO THE LOW PRESSURE AREA MOVING
THROUGH THE NORTH CENTRAL GULF OF MEXICO. COLDER AIR IN THE WAKE
OF THIS LOW...THEN A REINFORCEMENT OF COOLER AIR AND HIGH PRESSURE
ON FRIDAY...WILL KEEP NORTH TO NORTHEAST WINDS ON THE STRONGER
SIDE WEDNESDAY NIGHT THROUGH SATURDAY NIGHT. 22/TD

&&

DECISION SUPPORT...

DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
             FREEZING RAIN ADVISORY NW OF BTR TO MCB
             SMALL CRAFT ADVISORY THROUGH MON EVENING

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  32  45  35  43 /  70  30  70  90
BTR  34  48  39  46 /  60  30  60  90
ASD  37  50  41  48 /  60  40  50  90
MSY  39  49  43  49 /  60  40  60  90
GPT  38  51  43  48 /  60  40  50  90
PQL  38  51  42  49 /  60  30  50  90

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FREEZING RAIN ADVISORY FROM 9 PM MONDAY TO 9 AM TUESDAY FOR THE
     FOLLOWING ZONES: EAST FELICIANA...POINTE COUPEE...AND WEST
     FELICIANA.

GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT 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...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM...LAKE
     BORGNE...AND MISSISSIPPI SOUND.

MS...FREEZING RAIN ADVISORY FROM 9 PM MONDAY TO 9 AM TUESDAY FOR THE
     FOLLOWING ZONES: AMITE...PIKE...AND WILKINSON.

GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT 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...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM...LAKE
     BORGNE...AND MISSISSIPPI SOUND.

&&

$$







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