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

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400
FXUS64 KLIX 241739
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1239 PM CDT TUE MAR 24 2015

.AVIATION...

RATHER EXTENSIVE CUMULUS/STRATOCUMULUS FIELD HAS DEVELOPED ON THE
LOW LEVEL ONSHORE FLOW THIS MORNING. TWO DIFFERENT LAYERS OF
CLOUDS...ONE THIN BAND TRAPPED JUST BELOW THE INVERSION AT 850
MB...AND SOME LOWER CLOUDS GENERALLY AROUND 2500 FEET. WHILE MOST
AREAS WILL REMAIN VFR FOR THE REMAINDER OF THE DAY...COULD SEE
OCCASIONAL BROKEN CLOUDS WITH THE 2500 FOOT LAYER PROVIDING MVFR
CONDITIONS. WE SHOULD LOSE AT LEAST SOME OF THE CLOUDS AFTER
SUNSET...BUT MODEL SOUNDINGS DO SHOW THAT MOISTURE FURTHER BELOW
THE 850 MB INVERSION...CURRENTLY BEING OBSERVED NEAR 2500
FEET...COULD BUILD DOWN ENOUGH TO CREATE CEILINGS BETWEEN
1500-2000 FEET OVERNIGHT. TWO SCENARIOS EXIST...ONE WOULD BE FOR
THE 1500-2000 FOOT CEILINGS TO PREVAIL...THE OTHER WOULD BE FOR
SKIES TO CLEAR OVERNIGHT...PRODUCING THE POTENTIAL FOR RADIATION
FOG AT MOST TERMINALS. FOR THE MOST PART...THIS FORECAST PACKAGE
TRENDS TOWARD THE FIRST SCENARIO...WITH POTENTIAL FOR VFR
CONDITIONS AT ALL TERMINALS AROUND 15-16Z TOMORROW. 35

&&

.PREV DISCUSSION... /ISSUED 959 AM CDT TUE MAR 24 2015/

UPDATE...

SOME BREAKS IN A LOW STRATUS DECK OVER THE CWA ARE NOTED ON THE
LATEST VISIBLE SATELLITE IMAGERY OVER COASTAL MISSISSIPPI...THE
NORTHSHORE OF LAKE PONTCHARTRAIN...AND PARTS OF SOUTHWEST
MISSISSIPPI. HOWEVER...THE LOW STRATUS REMAINS SOCKED IN OVER THE
REST OF THE FORECAST AREA. HAVE ADJUSTED SKY COVER GRIDS UPWARD TO
REFLECT THE HIGHER AMOUNT OF CLOUD COVER FOR AREAS AROUND BATON
ROUGE AND NEW ORLEANS FOR THE REMAINDER OF THE DAY. EXPECT TO SEE
CONTINUED CLEARING FOR COASTAL MISSISSIPPI...THE NORTHSHORE OF
LAKE PONTCHARTRAIN...AND SOUTHWEST MISSISSIPPI WITH PARTLY CLOUDY
SKIES BEING THE RULE BY THE AFTERNOON. TEMPERATURES ARE STILL ON
TRACK...SO NO CHANGES MADE TO THE FORECAST HIGHS. 32

&

PREV DISCUSSION... /ISSUED 805 AM CDT TUE MAR 24 2015/

.SOUNDING DISCUSSION...
THE SOUNDING THIS MORNING IS DRY AND STABLE OVERALL BUT DEPICTS A
BIT OF LOW LEVEL MOISTURE FROM THE SFC TO 042 FT WITH WINDS FROM
THE EAST OR SOUTHEAST. THE TOP OF THAT LAYER MARKS A SHALLOW CLOUD
DECK AND 12 DEGREE F INVERSION. JUST ABOVE THE INVERSION IS A VERY
DRY AIRMASS WITH WINDS FROM THE EAST. WINDS BECOME WESTERLY BY 650
MB AND THE PEAK WIND IS 90 KTS AT 190 MB.

KRAUTMANN

PREV DISCUSSION... /ISSUED 415 AM CDT TUE MAR 24 2015/

SHORT TERM...
A RELATIVELY FLAT PRESSURE FIELD AND NON-DESCRIPT PATTERN OVER THE
GULF STATES THIS MORNING. LOW LEVEL MOISTURE TRAPPED BELOW A STEEP
SUBSIDENCE INVERSION HAS MAINTAINED A CLOUD DECK AROUND 3-4KFT
THAT WAS SLOWLY BECOMING ENRICHED BY MARITIME RETURN FLOW ALONG
THE MISSISSIPPI COAST WHERE CEILINGS WERE LOWERING. THIS HAS
ALLOWED FOG NOT FORM THUSFAR...BUT SOME LIGHT LOCALIZED FOG MAY
STILL RESULT BY DAYBREAK. MARINE LAYER AIR ADVANCES SLOWLY
NORTHWARD THROUGHOUT THE DAY WITH PERHAPS A BETTER CHANCE OF MORE
WIDESPREAD FOG TONIGHT AND WEDNESDAY MORNING. TEMPERATURES SHOULD
BE ABLE TO WARM INTO THE UPPER 70S TO LOWER 80S WHEN CLOUDS BREAK.
WENT PRETTY CLOSE TO MODEL BLENDED TEMPERATURE GUIDANCE.

LONG TERM...
COLD FRONT STILL EXPECTED TO MOVE THROUGH THE AREA THURSDAY
AFTERNOON WITH PRE-FRONTAL COMPRESSIONAL HEATING LIKELY TO BRING
TEMPERATURES WARMER THAN GUIDANCE...INTO THE AT LEAST THE LOWER
80S WITH MAYBE A LOCATION OR TWO IN THE MID 80S. THIS MAY AID IN
DESTABILIZING THE AIR MASS ENOUGH FOR THUNDERSTORM GENERATION. THE
CHAP GUIDANCE OFF THE NAM MODEL RUN DOES HINT AT A RISK OF LOW END
SEVERE POTENTIAL...WHILE THE GFS HAS NO INDICATIONS. WILL JUST
INDICATE GENERAL THUNDER AT THIS TIME BUT WILL BE MONITOR MODEL
TRENDS NEXT FEW RUNS. BELOW NORMAL TEMPERATURES ARE STILL
ANTICIPATED FOR THE WEEKEND WITH A STEADY WARMING TREND HEADING
INTO EARLY NEXT WEEK. RETURN FLOW NEXT TUESDAY MAY BE LADENED WITH
DEEP LAYERED MOISTURE AS A SOUTHERN BRANCH DISTURBANCE EJECTS
ACROSS THE LOWER STATES...BUT GREATER RAIN THREAT MAY HOLD OUT
WEST OF THE FORECAST AREA UNTIL BEYOND THIS FORECAST PACKAGE END
TIME. 24/RR

AVIATION...
LATEST OBS AND SATELLITE IMAGERY SHOWS MID LEVEL CLOUD
DECK MOVING IN FROM THE SOUTHEAST AND ENCOMPASSING MOST OF THE
TERMINALS. CIGS ARE GENERALLY BETWEEN 3K AND 4K FEET. CLOUDS MAY
HANG AROUND FOR A GOOD BIT OF THE DAY BEFORE SOME BREAKS SHOW UP BY
SUNSET AS SURFACE HEATING WANES. VFR SHOULD PREVAIL THROUGHOUT THE
DAY. MEFFER

MARINE...
BENIGN CONDITIONS ARE EXPECTED OVER THE COASTAL WATERS
THROUGH THURSDAY...WITH WINDS OF 5 TO 10 KNOTS VEERING FROM THE
NORTHWEST TO THE SOUTH OVER THIS PERIOD. THURSDAY NIGHT WILL BE A
PERIOD OF TRANSITION AS A STRONG COLD FRONT SWEEPS THROUGH THE
COASTAL WATERS. AS A RESULT...A PERIOD OF SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO FORM OVER THE COASTAL WATERS FRIDAY INTO
FRIDAY NIGHT. WINDS WILL SWITCH AROUND FROM NORTHEAST SATURDAY
MORNING TO SOUTHEAST BY THE EVENING AS SURFACE RIDGE TO THE NORTH
SLIDES EAST. WINDS WILL REMAIN ONSHORE SUNDAY AS THE HIGH BUILDS
INTO THE NORTHEASTERN GULF OF MEXICO. A BACKDOOR COLD FRONT MAY
APPROACH THE COASTAL WATERS EARLY NEXT WEEK BUT COULD BE IN A
WEAKENING STATE AND HAVE LITTLE IMPACT.

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  77  56  80  56 /   0  10  10  10
BTR  78  57  81  57 /   0  10  10  10
ASD  77  59  80  61 /  10  10  10  10
MSY  76  61  80  62 /  10  10  10  10
GPT  75  61  78  62 /  10  10  10  10
PQL  76  60  79  61 /  10  10  10  10

&&

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

$$



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