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

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792
FXUS64 KLIX 300057
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
757 PM CDT MON SEP 29 2014

.SOUNDING DISCUSSION...

THE 00Z SOUNDING SHOWS CONTINUED DRYING OF THE OVERALL ATMOSPHERE
AS COMPARED TO THE 12Z SOUNDING THIS MORNING. PRECIPITABLE WATER
VALUES HAVE DECREASED BY NEAR 0.20 INCHES TODAY AND DEEP LAYER
NORTH AND NORTHWEST FLOW REMAINS IN PLACE. THERE IS STILL A REGION
OF MUCH DRIER AIR FROM AROUND 450MB AND UP...WITH CAPPING ALOFT
NOTED WHERE TEMPERATURES WARM AS THE AIRMASS DRIES OUT. BELOW THIS
CAP...A REGION OF WEAK INSTABILITY WAS IN PLACE TODAY. ALTHOUGH
SURFACE BASED CAPE WAS NOTED AT 1600 J/KG...THE OVERALL LAPSE
RATES WERE VERY WEAK AND CAPE WAS ACTUALLY QUITE SKINNY. AS A
RESULT...THERE WAS LITTLE IN THE WAY OF DEEPER CONVECTIVE
DEVELOPMENT TODAY. 32

&&

.PREV DISCUSSION... /ISSUED 310 PM CDT MON SEP 29 2014/

SYNOPSIS...

FRONTAL SYSTEM REMAINS OVER THE NORTHERN GULF THIS AFTERNOON.
ABUNDANT MOISTURE IN THE LOWEST 100MB KEPT CLOUD COVER ACROSS THE
AREA ALL MORNING AND HAS REALLY ONLY STARTED BREAKING UP SINCE
18Z. WHERE BREAKS IN THE CLOUDS OCCURRED...ISOLATED SHOWERS
DEVELOPED...AND ARE MOVING WITH THE LOW LEVEL FLOW TOWARD THE
SOUTHWEST. MID AFTERNOON TEMPERATURES ARE GENERALLY IN THE LOWER
AND MIDDLE 80S WITH DEW POINTS AROUND 70 DEGREES.

SHORT TERM...

SHORTWAVES OVER THE TENNESSEE VALLEY AND THE FLORIDA PANHANDLE
WILL CONTINUE TO MOVE EASTWARD OFF THE COAST TONIGHT. BASED ON
CURRENT AREAL COVERAGE OF PRECIPITATION...MET GUIDANCE POPS ARE
OVERDONE. BUFR SOUNDINGS FOR TOMORROW SHOW THE AIRMASS IS GOING TO
BE A BIT DRIER THAN TODAY. COMBINED WITH NO ORGANIZED
FORCING...MET GUIDANCE AGAIN APPEARS SIGNIFICANTLY OVERDONE. WILL
NOT GO QUITE AS DRY AS THE MAV GUIDANCE...AND WILL KEEP SLIGHT
CHANCE MENTION IN THE FORECAST. ONSHORE FLOW WILL RETURN ON
WEDNESDAY WITH AN INCREASE IN MOISTURE. PRECIPITABLE WATER VALUES
WILL RETURN TO NEAR 2 INCHES BY WEDNESDAY AFTERNOON...AND WILL USE
MAV POPS AS A BASELINE. STRONG TROF WILL BE MOVING THROUGH THE
SOUTHERN PLAINS ON THURSDAY...PUSHING A COLD FRONT AHEAD OF IT.
SCATTERED CONVECTION IS EXPECTED TO DEVELOP DURING THE AFTERNOON
HOURS.

WILL BE TRENDING TOWARD THE WARMER MAV GUIDANCE THROUGH THE SHORT
TERM...BUT STAY A DEGREE OR TWO BELOW THE WARMEST HIGH
TEMPERATURES. 35

LONG TERM...

MEDIUM RANGE MODEL SOLUTIONS ARE PRETTY CLOSE ON TIMING OF COLD
FRONTAL PASSAGE FRIDAY AFTERNOON AND EVENING. THUNDERSTORMS WILL
BE LIKELY IN ADVANCE OF THE FRONT THURSDAY NIGHT INTO FRIDAY.
SOLUTIONS WOULD INDICATE A LINE OF THUNDERSTORMS IN ADVANCE OF THE
FRONT. BEST DYNAMICS WILL BE WELL NORTH OF THE AREA...BUT A FEW
STRONG STORMS POSSIBLE. ANY PRECIPITATION SHOULD BE OFFSHORE BY
LATE FRIDAY EVENING. PRECIPITABLE WATER VALUES DROP FROM ABOUT 1.8
INCHES AT 18Z FRIDAY TO ABOUT 0.5 INCHES 12 HOURS LATER. EXPECT A
DRY FORECAST FOR THE REMAINDER OF THE EXTENDED FORECAST PERIOD.

WILL TREND TOWARD THE MEX GUIDANCE FOR FRIDAY...BUT BEHIND THE
FRONT...MEX DATA APPEARS TO BE TOO WARM FOR SATURDAY AND SUNDAY.
H925 TEMPERATURES DROP BY 6-8C BEHIND THE FRONT...SO HIGH
TEMPERATURES ARE GOING TO STRUGGLE TO GET MUCH PAST 80 FOR THE
WEEKEND. SUNDAY MORNING LIKELY TO BE THE COOLEST MORNING OF THE
EXTENDED WITH NORTHSHORE LOCATIONS DROPPING WELL INTO THE
50S...WITH SOME MODERATION BEYOND THAT. 35

AVIATION...

BKN MVFR CEILINGS AT EARLY AFTERNOON GIVING WAY TO MAINLY VFR
CONDITIONS BY LATE AFTERNOON EXCEPT NEAR AREAS OF SCATTERED SHOWERS.
FORECAST SOUNDINGS SHOW OVERALL LOWERING OF MOISTURE CONTENT IN
LOWER PART OF ATMOSPHERE DURING OVERNIGHT HOURS...AND MOS GUIDANCE
FOLLOWS TREND WITH VFR CONDITIONS DOMINATE. 18Z TAFS REFLECT VFR
GUIDANCE TRENDS WITH MVFR VIS RESTRICTIONS POSSIBLE AROUND SUNRISE.
VFR CONDITIONS EXPECTED ON TUESDAY. 21

MARINE...

GENERALLY LIGHT EAST TO NORTHEAST...BUT OCCASIONALLY VARIABLE...
WINDS WILL PREVAIL TONIGHT ACROSS THE COASTAL WATERS...ALTHOUGH
SOMEWHAT HIGHER WINDS WILL BE POSSIBLE ACROSS AREAS TO THE EAST OF
THE MISSISSIPPI RIVER. ONSHORE FLOW WILL BEGIN TO DEVELOP LATE
TUESDAY INTO WEDNESDAY...AND WILL INCREASE WEDNESDAY NIGHT INTO
THURSDAY AS THE PRESSURE GRADIENT INCREASES BETWEEN A DEPARTING
HIGH OVER THE EASTERN SEABOARD AND DEVELOPING LOW IN THE PLAINS. A
STRONG COLD FRONT WILL PUSH ACROSS THE COASTAL WATERS FRIDAY AND
FRIDAY NIGHT. THIS MAY REQUIRE AT LEAST EXERCISE CAUTION HEADLINES
FOR FRIDAY NIGHT INTO SATURDAY. 35

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 TO HIGH RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  69  88  70  88 /  20  10  20  30
BTR  70  89  71  90 /  20  20  20  30
ASD  69  87  70  87 /  20  20  20  20
MSY  74  87  74  87 /  20  20  20  30
GPT  70  86  71  85 /  30  20  20  20
PQL  67  87  68  85 /  30  20  20  20

&&

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

$$







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