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

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248
FXUS64 KLIX 221629
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1129 AM CDT SUN MAR 22 2015

.UPDATE...

UPDATED FOR RADAR TRENDS AND TO ACCOUNT FOR INSTABILITY AND
SUFFICIENT FORCING TO HAVE MENTION OF THUNDERSTORMS IN THE
FORECAST THIS AFTERNOON. THE AREA WITH THE BEST COMBINATION OF
INSTABILITY AND SHEAR TO SUPPORT STRONG TO MARGINALLY SEVERE
THUNDERSTORMS WILL BE OVER SOUTHEAST MISSISSIPPI AND POSSIBLY
SOME OF THE ADJACENT NORTHSHORE AREAS OF SOUTHEAST LOUISIANA.
BREAKS IN THE THICKER CLOUDS SHOULD ALLOW THE HIGHS TO RISE NEAR
THE FORECAST VALUES AS THERE HAS ALREADY BEEN SOME QUICK RISES IN
THE LAST HOURS. UPDATES ARE OUT. 22/TD

&&

.PREV DISCUSSION... /ISSUED 824 AM CDT SUN MAR 22 2015/

SOUNDING DISCUSSION...
UNIFORM SW TO W FLOW FROM SFC UPWARD. SPEEDS PEAK OUT AT 110KT
FROM 34KFT TO 37KFT. MOIST SOUNDING WITH A DRY REGION FROM
19800KFT TO 32KFT. PW MEASURED AT 1.65 IN WITH FCST CAPE TO BE
1117 J/KG THIS AFTERNOON. THIS MORNING`S FREEZING LEVEL CAME IN
AT 12743FT. NOT MUCH IN THE WAY OF INSTABILITY WITH SLIM AREA OF
POTENTIAL LIFT AND AN UPPER INVERSION CAP 20KFT WHICH DOES NOT
SUPPORT WIDESPREAD THUNDERSTORMS. PLENTY OF SFC MOISTURE AND WILL
HAVE TO WATCH FOR FOG OVER THE NEXT FEW DAYS.

PREV DISCUSSION... /ISSUED 443 AM CDT SUN MAR 22 2015/

SHORT TERM...
WEAK SURFACE LOW OFF THE SOUTHWEST LOUISIANA COAST IS EXPECTED TO
RIDE THE STATIONARY FRONT EASTWARD TODAY. THE SYSTEM IS DEVOID OF
MUCH UPPER LEVEL DYNAMICS AS TROUGHING IS TAKING PLACE OVER THE
DESERT SOUTHWEST...FORCING RIDGING DOWNSTREAM WITH LIMITED
BAROCLINICITY IN THE FRONTAL ZONE. HAVE LIMITED THUNDER DUE TO
SHALLOW NATURE OF INSTABILITY AND WENT LOWER THAN GUIDANCE ON RAIN
CHANCES FOR REMAINDER OF THE DAY. UPPER LEVEL LOW OVER RED RIVER
VALLEY OF NORTH TEXAS WILL BE LIFTING NORTHEAST DURING THE DAY AS
WELL. DRY SLOT MOVING OUT OF EAST TEXAS WILL ALSO LIMIT RAINFALL
COVERAGE TODAY. A RATHER FLAT PRESSURE GRADIENT BECOMES
ESTABLISHED TONIGHT AND MONDAY WITH PERHAPS A SHOT AT SOME DECENT
RADIATIONAL FOG FORMATION OVERNIGHT AND AGAIN MONDAY NIGHT DUE TO
RESIDUAL MOISTURE ABOUT. TEMPERTURES MAY ALSO WARM A FEW DEGREES
ABOVE GUIDANCE CONCENSUS DURING THE DAYTIME. HAVE GONE ON AVERAGE
2-3 DEGREES ABOVE GUIDANCE FOR MONDAY AND TUESDAY.

LONG TERM...
ONSHORE FLOW BECOMES DEEPER ON WEDNESDAY TO BRING AN INCREASE IN
HUMIDITY LEVELS AHEAD OF WHAT APPEARS TO BE A STRONG COLD FRONTAL
PASSAGE FOR THURSDAY. COMPRESSIONAL HEATING WILL LIKELY BRING
TEMPERATURES ON THE WARM SIDE OF GUIDANCE FOR WEDNEDAY AND
THURSDAY PRIOR TO FRONTAL PASSAGE THURSDAY AFTERNOON. FRONT SHOULD
BE ACCOMPANIED BY THUNDERSTORMS...BUT MODELS ARE CURRENTLY LIGHT
ON ATTENDANT CONVECTION UNTIL THE FRONT ACTUALLY REACHES THE
COAST. TEMPERATURES IN GUIDANCE ARE INDICATING BELOW NORMAL
FRIDAY AND SATURDAY BUT WELL ABOVE ANY FREEZE OR FROST CONCERNS AT
THIS TIME.

AVIATION...
A MIXTURE OF ALL CATAEGORIES OUT THERE THIS MORNING AS A SURFACE
LOW CONTINUES TO PUSH EAST. EXPECT MVFR TO IFR CONDITIONS TO
PREVAIL THIS MORNING AS SHOWERS MOVE THROUGH. SOME LIGHT PATCHY
FOG IS POSSIBLE THIS MORNING. EXPECT ERRATIC CIGS THROUGH THE
MORNING HOURS AS SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE
TODAY. EXPECT RAIN CHANCES TO DECREASE AFTER 18Z TODAY AS
CONDITIONS IMPROVE TO VFR CONDITIONS IN THE AFTERNOON. CIGS SHOULD
COME BACK DOWN LATER ON TONIGHT INTO THE MVFR RANGE AT MOST SITES.

MARINE...
NOT MUCH RESPONSE TO WEAK SURFACE LOW OVER NORTHWEST GULF THIS
MORNING WITH RELATIVELY LIGHT WINDS AND LOW SEAS AT THIS TIME.
THIS SHOULD REMAIN THE CASE THROUGH TUESDAY BEFORE ONSHORE FLOW
BECOMES MORE PRONOUNCED WEDNESDAY AHEAD OF COLD FROTN. THIS FRONT
IS LIKELY TO MOVE OFF THE COAST THURSDAY AFTERNOON OR EARLY
EVENING AND BRING SMALL CRAFT ADVISORY CONDTIONS IN ITS WAKE LATE
THURDAY INTO FRIDAY AS COLD HIGH PRESSURE BUILDS INTO THE NORTH
GULF OVER WARMING WATERS. 24/RR

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  76  55  70  53 /  50  10  10  10
BTR  80  56  74  53 /  50  10  10  10
ASD  80  59  73  56 /  60  10  10  10
MSY  81  59  73  59 /  50  10  10  10
GPT  79  60  72  57 /  60  10  10  10
PQL  79  60  73  55 /  60  10  10  10

&&

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

$$



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