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

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758
FXUS64 KLIX 130121
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
721 PM CST FRI DEC 12 2014


.SOUNDING DISCUSSION...
THERE WERE NO PROBLEMS WITH THE UPPER AIR RELEASE THIS EVENING.
THE SOUNDING DEPICTED A STABLE ATMOSPHERE. AN INVERSION WAS
PRESENT JUST BELOW 875 MB. THE PRECIPITABLE WATER VALUE OF 0.97
INCH WAS JUST SLIGHTLY MORE MOIST THAN THAT OF THE PROFILE THIS
MORNING. A SATURATED LAYER WAS PRESENT BETWEEN 900 AND 925 MB.
NORTHERLY FLOW PREVAILED IN THE LOWER LEVELS OF THE ATMOSPHERE...
NORTHWESTERLY WINDS IN THE MID LEVELS...AND WESTERLY FLOW IN THE
UPPER LEVELS. 11

&&

.PREV DISCUSSION... /ISSUED 306 PM CST FRI DEC 12 2014/

SHORT TERM...
CONTINENTAL HIGH PRESSURE OVER THE MISSISSIPPI VALLEY WILL SLOWLY
MIGRATE EAST AND MODERATE THROUGH THE WEEKEND WITH SOME SUBTLE
FRINGE RETURN FLOW BECOMING ESTABLISHED MONDAY. MODELS ARE IN
PRETTY GOOD AGREEMENT IN SHOWING A PACIFIC COLD FRONT MOVING INTO
THE FORECAST AREA MONDAY NIGHT. THIS IS THE SAME SYSTEM THAT IS
CURRENTLY CAUSING MAJOR IMPACTS OVER SOUTHERN CALIFORNIA TODAY.
RAINFALL SHOULD ACCOMPANY THE FRONTAL PASSAGE BUT TIME HEIGHT
PROFILES SHOW THE MOISTURE BEING QUITE SHALLOW AND LACKING OF AN
OMEGA STRUCTURE OR INSTABILITY FOR DEEP CONVECTION. HAVE REMOVED
THUNDER WORDING FOR MONDAY NIGHT AND WENT STRICTLY SHOWERS.

LONG TERM...
NO REAL WEATHER ISSUES OF NOTE EXPECTED TUESDAY ONWARD AS
CONTINENTAL HIGH PRESSURE THAT IS INITIALLY OF PACIFIC MARITIME
ORIGIN BUT GAINS CANADIAN POLAR CONTINENTAL INFLUENCES ON
WEDNESDAY. MODELS THEN LATCH ONTO A VIGOROUS SOUTHERN BRANCH
SYSTEM MOVING INTO THE SOUTHWEST U.S. AND NORTHERN MEXICO LATTER
PART OF THE WEEK THAT BRINGS INSTABILITY BACK INTO THE AREA FOR
NEXT WEEKEND. THE ECMWF AND THE GFS SHOW THE BULK OF THE DYNAMICS
LIFTING NORTH OF THE FORECAST AREA NEXT SATURDAY BUT THE RUN-TO-
RUN CHANGES HAVE BEEN LARGE OF LATE WITH THIS SYSTEM. THE LOCAL
HOVMOLLER ANALYSIS DOES INDICATE A STRONG SIGNAL PASSAGE WITH THAT
FEATURE IN THE DEC 20TH TIME FRAME...SO THIS DOES BEAR WATCHING BUT
AT THIS TIME...IT REMAINS UNCERTAIN WHAT PATH THE SURFACE AND
UPPER LEVEL DYNAMICS ACTUALLY TRACKS. WARM AIR ADVECTION AHEAD OF
THIS SYSTEM MAY BE ROBUST ENOUGH TO BRING A NIGHT OR TWO OF SEA
FOG CONSIDERATIONS LATTER PART OF NEXT WEEK. 24/RR

AVIATION...
A SCATTERED TO BROKEN STRATUS DECK RANGING FROM 3500 TO 5000 FEET
WILL LINGER OVER THE TERMINALS THROUGH THE EVENING HOURS.  CEILINGS
WILL RISE UP TO BETWEEN 5000 AND 8000 FEET TONIGHT AND REMAIN IN
THAT RANGE DURING THE DAY TOMORROW.  OVERALL...VFR CONDITIONS WILL
BE THE RULE AT ALL TERMINALS THROUGH THE FORECAST PERIOD. 32

MARINE...
RELATIVELY LIGHT WINDS AND LOW SEAS ARE EXPECTED THIS WEEKEND AS
WEAKENING HIGH PRESSURE REMAINS SETTLED OVER THE NORTH GULF
WATERS. A FRONTAL PASSAGE LATE MONDAY NIGHT INTO TUESDAY MORNING
WILL BRING A SLIGHT INCREASE IN NORTHWESTERLY WINDS BUT SHOULD
REMAIN BELOW HEADLINE CRITERIA GIVEN THE DEGREE OF SEA SURFACE
TEMPERATURE COOLING THAT HAS TAKEN PLACE THE PAST MONTH OR SO. 24/RR

CLIMATE...
PER NWS POLICY...A DROUGHT INFORMATION STATEMENT...NEWDGTLIX AXUS74...IS
ISSUED WHENEVER A DROUGHT CLASSIFICATION OF D2 OR WORSE IS
INDICATED WITHIN THE FORECAST AREA PER U.S. DROUGHT MONITOR. THIS
PRODUCT WAS ISSUED THIS MORNING AT 10 AM CST ALONG WITH A
SLIDESHOW BRIEFING PACKAGE...WHICH CAN BE OBTAINED ON OUR WEB PAGE
AS A TOP NEWS OF THE DAY BULLET. MEDIA OUTLETS ARE INVITED TO
DISSEMINATE THE INFORMATION IN NEWSCASTS AND SOCIAL MEDIA LINKS.

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  44  68  45  71 /  10  10  10   0
BTR  47  70  48  73 /  10   0   0   0
ASD  44  68  45  70 /  10  10  10   0
MSY  48  67  50  70 /  10  10   0   0
GPT  44  66  46  67 /  10  10   0   0
PQL  39  66  41  69 /  10   0   0   0

&&

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

$$







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