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

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837
FXUS64 KLIX 310541
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1241 AM CDT TUE MAR 31 2015

.AVIATION...

CURRENTLY VFR AT ALL SITES EXCEPT KHUM WHERE LOCALIZED FOG HAS
LOWERED CONDITIONS BELOW FIELD MINIMUMS. SURFACE HIGH OVER THE
EASTERN GULF IS PRODUCING SOUTHWESTERLY FLOW ACROSS MOST
TERMINALS. QUESTION FOR THE OVERNIGHT HOURS IS WHETHER WINDS WILL
DECOUPLE AND GO COMPLETELY CALM. IF THIS OCCURS...THERE WILL BE
THE POTENTIAL FOR RADIATION FOG WHICH COULD LOWER CONDITIONS TO
VLIFR. IF WINDS STAY UP...NO FOG...VERY SIMILAR TO YESTERDAY
MORNING. FOR NOW...HAVE LIMITED MENTION OF IFR VISIBILITIES TO
KMCB...KHUM AND KASD. ANY FOG THAT DOES OCCUR WILL SEE CONDITIONS
IMPROVE PRIOR TO 15Z. BEYOND 15Z...VFR CONDITIONS ARE EXPECTED
DURING THE DAYTIME HOURS ON TUESDAY. ANY CONVECTION THAT WOULD
DEVELOP WOULD BE EXTREMELY ISOLATED AND NOT ENOUGH AREAL COVERAGE
TO JUSTIFY A FORECAST MENTION MORE THAN 12 HOURS OUT IN FORECAST.

35

&&

.PREV DISCUSSION... /ISSUED 750 PM CDT MON MAR 30 2015/

..SOUNDING DISCUSSION...

NEARLY DRY ADIABATIC TEMPERATURE PROFILE FROM THE SURFACE TO ABOUT
8000 FEET WHERE AN INVERSION IS NOTED. PRECIPITABLE WATER VALUES
REMAIN AROUND 1 INCH THIS EVENING AS HAS BEEN THE CASE THE LAST
FEW BALLOON RELEASES. WINDS WERE FROM THE SOUTHWEST AT THE SURFACE
AND THEN ROTATED AROUND TO FROM THE NORTHWEST IN THE MIDLEVELS AND
BACK TO FROM THE WEST IN THE UPPER LEVELS. A PEAK WIND SPEED OF
114 KNOTS WAS LOCATED AT 36300 FEET.

00Z BALLOON INFO: NO ISSUES WITH THE FLIGHT THIS EVENING THAT
LASTED 100 MINUTES AND TRAVELED 55 MILES DOWNRANGE FROM THE
OFFICE. THE BALLOON ATTAINED A HEIGHT OF 20.5 MILES ABOVE THE
GROUND BURSTING OVER CHANDELEUR SOUND.

ANSORGE

PREV DISCUSSION... /ISSUED 306 PM CDT MON MAR 30 2015/

SHORT TERM... COLD FRONT WELL TO THE NORTH OF THE CWA THAT IS
ATTEMPTING TO MOVE SOUTH LOOKS TO BE STALLING AND STRETCHING EAST
ACROSS NORTHERN LA/MS/AL. THE UPPER LEVEL TROUGH THAT THIS BOUNDARY
IS ASSOCIATED WITH IS SO FAR NORTH AND MOVING EAST SO MUCH THAT
THERE WILL NOT BE ENOUGH PUSH FOR THE FRONT TO MAKE IT TO THE CWA.
THUS NOT EXPECTING MUCH IN THE WAY OF PRECIP THE REST OF TODAY AND
OVERNIGHT. HAVE COMPLETELY DROPPED POPS FOR TONIGHT AND TRIMMED BACK
AFTN POPS TO MAINLY SW AND COASTAL MS COUNTIES. NOT VERY CONFIDENT
THAT ANY OF THEM WILL SEE PRECIP. TUESDAY AND TUESDAY NIGHT WILL BE
A CONTINUATION OF DRY AND WARM PERIOD AS WEAK UPPER LEVEL RIDGE
TRACKS EAST ACROSS THE GULF COAST.

MEFFER

LONG TERM... //PREVIOUS DISCUSSION// THE NEXT SYSTEM OF CONCERN
WILL BE A SHORTWAVE TROUGH MOVING OUT OF THE BAJA MEXICO REGION THAT
WILL MOVE EAST ACROSS CENTRAL/SOUTH TEXAS AND ADJACENT MEXICO
TUESDAY NIGHT...AND THEN DAMPEN/WEAKEN AS IT MOVES INTO THE CENTRAL
GULF COAST REGION WEDNESDAY NIGHT. THE MODELS HAVE TRENDED WEAKER
WITH THIS SYSTEM AS IT MOVES THROUGH THE FORECAST AREA...HOWEVER THE
ECMWF STILL PAINTS FAIRLY WIDESPREAD LIGHT TO MODERATE RAINFALL
AMOUNTS WEDNESDAY INTO THURSDAY WHILE THE GFS IS DRIER AND MORE
SPORADIC WITH THE AREAL COVERAGE. THE GFS MOS GUIDANCE NOW DOES NOT
SHOW ANY POP OVER 10 PERCENT DURING THESE PERIODS...HOWEVER HAVE
HELD ONTO 20 TO 30 PERCENT CHANCES FOR SHOWERS AND SOME
THUNDERSTORMS WEDNESDAY INTO THURSDAY TO MAINTAIN FORECAST
CONSISTENCY.

THE WESTERLIES AND UPPER JET STREAM WILL BE SAGGING SOUTH INTO THE
SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY FRIDAY AND FRIDAY NIGHT
AS A SERIES OF SHORTWAVE TROUGH/DISTURBANCES MOVE THROUGH. THIS IS
EXPECTED TO DRIVE A PACIFIC COLD FRONT THROUGH THE FORECAST AREA
FRIDAY NIGHT AND EARLY SATURDAY. THE FORCING WILL NOT BE THAT STRONG
AND MOISTURE CONTENT NOT THAT HIGH...SO MOSTLY LIGHT QPF AMOUNTS
FROM ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE
ANTICIPATED FRIDAY THROUGH SATURDAY MORNING WITH THE HIGHEST RAIN
CHANCE LOOKING TO BE ON FRIDAY NIGHT INTO SATURDAY MORNING ACROSS
NORTHERN AREAS. TEMPERATURES ARE EXPECTED TO LOWER TO NEAR TO
SLIGHTLY BELOW NORMAL OVER THE WEEKEND.

AVIATION...LATEST VIS SATELLITE SHOWS WELL DEVELOPED CU FIELD OVER
THE ENTIRE NORTH CENTRAL GULF COAST REGION. MOST CEILINGS ARE IN THE
3K TO 4K FOOT RANGE. EXPECT THIS DECK TO DISSIPATE AROUND SUNSET.
LOWER LEVEL CLOUDS AROUND IFR/MVFR HEIGHTS MAY DEVELOP EARLY
TOMORROW MORNING. AREAS WITH LESS CLOUD COVER WILL BE MORE PRONE TO
FOG DEVELOPMENT. CURRENT WINDS OF 7 TO 12 KNOTS WILL FADE THIS
EVENING AND OVERNIGHT TO MAINLY LIGHT/VARIABLE OR EVEN CALM.

MEFFER

MARINE...AT 08Z...SURFACE RIDGE CENTERED EAST OF THE COASTAL AREAS
WILL REMAIN IN PLACE FOR THE REMAINDER OF THE WEEK. THIS WILL RESULT
IN SOUTHERLY FLOW WITH NO STRONG WEATHER SYSTEMS MOVING THROUGH THE
COASTAL WATERS. THE OVERALL AVERAGE WIND SPEED THROUGH THIS PERIOD
WILL BE 10 KNOTS WITH PERIODS ABOUT 5 KNOTS ABOVE AND 5 KNOTS BELOW
THIS. A COLD FRONT WILL SWING THROUGH SATURDAY AND BRING NORTHERN
WINDS OF AROUND 20 KNOTS TO THE COASTAL WATERS.

MEFFER

DECISION SUPPORT...
DSS CODE...GREEN.
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 TONIGHT RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  60  81  63  82 /  10  20  30  30
BTR  61  82  64  84 /  10  20  30  30
ASD  59  80  64  81 /   0  20  20  30
MSY  64  81  67  81 /   0  20  20  20
GPT  61  77  65  77 /   0  20  20  20
PQL  60  79  63  78 /   0  20  20  20

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&

$$



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