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

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825
FXUS64 KLIX 302131
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
431 PM CDT TUE SEP 30 2014

.SYNOPSIS...

WEAK HIGH PRESSURE RIDGE EXTENDS FROM LAKE SUPERIOR TO THE
MISSISSIPPI COAST. OLD FRONTAL BOUNDARY REMAINS OVER THE CENTRAL
GULF TO THE SOUTH OF OUR AREA. LOW PRESSURE IS OVER SOUTH DAKOTA
WITH A COLD FRONT INTO WEST TEXAS. THIS WILL BE A PLAYER IN OUR
FORECAST LATER IN THE WEEK. SOME VERY ISOLATED SHOWERS OVER THE
AREA...MAINLY OVER PLAQUEMINES PARISH AND THE SURROUNDING COASTAL
WATERS. TEMPERATURES GENERALLY IN THE 80S AT MID AFTERNOON WITH
DEW POINTS FROM MID 60S NORTH TO MID 70S AT BOOTHVILLE.

&&

.SHORT TERM...

EXPECT ISOLATED PRECIPITATION TO DIE OFF BEFORE SUNSET AND WILL
NOT CARRY MENTION OF PRECIPITATION IN THE OVERNIGHT PORTION OF THE
FORECAST. AS FRONTAL SYSTEM MOVES THROUGH THE GREAT PLAINS
TOMORROW...ONSHORE FLOW WILL COMMENCE THE RETURN OF MOISTURE. THIS
WILL INCREASE RAIN CHANCES...MAINLY OVER WESTERN PORTIONS OF THE
AREA ON WEDNESDAY. FRONTAL SYSTEM WILL APPROACH THE AREA THURSDAY
NIGHT AND MOVE THROUGH DURING THE DAY ON FRIDAY. SOME TIMING
DIFFERENCES ON FRONTAL PASSAGE...WITH FORECAST TRENDING AWAY FROM
SLOWER NAM SOLUTION. BEST CHANCES FOR CONVECTION APPEAR TO BE LATE
THURSDAY NIGHT INTO FRIDAY MORNING...WHERE SOME LIKELY POPS ARE
INDICATED. ANTICIPATE THAT AS TIMING DIFFERENCES DIMINISH...POPS
WILL PROBABLY GET RAISED IN ONE OF THOSE TWO PERIODS IN LATER
FORECASTS.

HAVE GONE WITH A BLENDED SOLUTION ON TEMPERATURES THROUGH THURSDAY
AS NUMBERS ARE FAIRLY CLOSE FROM THE USUAL GUIDANCE SOURCES.
FRIDAY TEMPERATURES WILL BE DEPENDENT ON TIMING OF COLD FRONTAL
PASSAGE. HAVE TRENDED A BIT COOLER THAN MAV HIGHS...CLOSER TO
ECMWF BIAS CORRECTED NUMBERS. 35

&&

.LONG TERM...

THE EXTENDED FORECAST BEYOND FRIDAY WILL BE DRY...AND CONSIDERABLY
LESS HUMID ACROSS THE AREA AS THE COLD FRONT MOVES WELL INTO THE
GULF OF MEXICO. DRIER AIR WILL OVERSPREAD THE AREA INTO EARLY NEXT
WEEK. ANOTHER SHORTWAVE REINFORCING THE COOLER AND DRIER AIR WILL
PUSH A FRONT THROUGH THE AREA MONDAY NIGHT OR TUESDAY. NOT OUT OF
THE QUESTION A FEW SHOWERS COULD OCCUR WITH THIS FRONT...BUT WILL
KEEP FORECAST DRY FOR NOW.

DEFINITE COOLING TREND BEHIND THE FRONT WITH THICKNESSES AND H925
TEMPERATURES DICTATING ABOUT A 10 DEGREE COOLOFF ON HIGH
TEMPERATURES...AND POSSIBLY CLOSER TO 15-20 DEGREES ON LOW
TEMPERATURES FROM FRIDAY TO SUNDAY AT SOME NORTHSHORE LOCATIONS
NORMALLY SUBJECT TO DRAINAGE LIKE SLIDELL AND PASCAGOULA. A BRIEF
MINOR MODIFICATION TO THE AIRMASS MONDAY BEFORE THE REINFORCING
FRONT DROPS OVERNIGHT LOWS BACK TO SLIGHTLY BELOW NORMAL FOR
TUESDAY AND WEDNESDAY MORNINGS. 35


&&

.AVIATION...

EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE EVENING AND OVERNIGHT
HOURS. THERE IS A CHANCE FOR SOME PATCHY FOG TO DEVELOP OVER
PORTIONS OF THE AREA OVERNIGHT ESPECIALLY NEAR DAYBREAK. HAVE
ADDED FOG IN TO SOME OF THE TAFS FOR THE EARLY MORNING HOURS.
13/MH

&&

.MARINE...

NO MAJOR CHANGES TO THE MARINE FORECAST. THINGS STILL LOOK TO BE
RELATIVELY CALM. EXPECT LIGHT EAST TO SOUTHEAST WILL PREVAIL.
ONSHORE FLOW WILL BEGIN TO DEVELOP WEDNESDAY. THIS FLOW 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. GFS SHOWS WARM AIR
ADVECTION AS THE MAIN TROUGH MOVES TO THE EAST COAST SATURDAY AND
SURFACE HIGH OVER THE AREA. EURO HOLD COLD AIR ADVECTION LONGER INTO
SATURDAY NIGHT. HAVE INCREASED ALL IN ALL...A SMALL CRAFT ADVISORY
HEADLINES MAY BE NEEDED FOR FRIDAY NIGHT INTO SATURDAY. 13/MH

&&

.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  71  88 /  10  30  20  60
BTR  70  88  72  89 /  10  40  30  50
ASD  69  87  72  88 /  10  30  20  60
MSY  73  87  74  88 /  10  30  30  50
GPT  70  86  73  85 /  10  20  20  50
PQL  68  86  72  86 /  10  10  20  50

&&

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

$$







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