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

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FXUS64 KLIX 020249
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
949 PM CDT TUE SEP 1 2015

.UPDATE...
REGIONAL RADARS SHOWED CONVECTION OVER SOUTHWEST LOUISIANA COASTAL
WATERS. IR SAT IMAGERY DISPLAYED CLOUD TOPS SLIGHTLY WARMING CLOUD
TOP TEMPS WITH THIS CONVECTION THROUGH 03Z THIS EVENING. HRRR
SHOWED QPF VALUES OF TRACE TO 0.01 SPREADING NORTH OVER
ATCHAFALAYA BASIN THROUGH 12Z. 00Z NAM REVEALED MODEL SOUNDING
JUST SOUTH OF BTR WITH SOUTHWEST FLOW THROUGHOUT COLUMN WITH
MOIST LAYER ABV 15KFT AROUND 06Z...THEN LOWERING TO 3KFT BY 12Z.
DISSIPATING SHOWERS MAY WORK INLAND...SO PUSHED ISOLATED COVERAGE TO
BTR AND WEST BACK OF MS RIVER THROUGH 12Z. OTHERWISE...AFTERNOON
PACKAGE IS ON TRACK.

&&

.PREV DISCUSSION... /ISSUED 331 PM CDT TUE SEP 1 2015/

SHORT TERM... UPPER LEVEL PATTERN ANALYSIS GENERALLY SHOWS AN
INVERTED TROUGH ACROSS THE SOUTHEASTERN THIRD OF THE COUNTRY. UNDER
THAT REGION EXISTS AN AREA OF WEAKNESS THAT EXTENDS FROM NEAR THE
GREAT LAKES SOUTHWESTWARD INTO SOUTH TEXAS. THE CWA IS CURRENTLY IN
SOMEWHAT OF A DRY SLOT BETWEEN THE THAT AREA ANOTHER PLUME OF
MOISTURE IN THE EASTERN GULF THAT WAS ASSOCIATED WITH THE REMNANTS OF
ERIKA. SHOWERS HAVE BEEN TRYING TO NUDGE INTO THE WESTERN FRIDGES OF
THE FORECAST AREA ALONG THE ATCHAFALAYA BASIN TODAY. NOT MUCH OF
THIS IS BEING REALIZED BUT THE POTENTIAL IS THERE SO HAVE KEPT
MINIMAL POPS FROM MORNING FCST UPDATE. IF ANY CONVECTION DOES OCCUR
IT SHOULD DISSIPATE THIS EVENING. DID ADD PATCHY FOG TO THE ZONES
FOR ALONG I-12 AND NORTHWARD FOR THE OVERNIGHT PERIOD. MODELS MISSED
IT FOR THIS MORNING AND SIMILAR LOWER ATMOSPHERIC CONDITIONS SHOULD
YIELD AT LEAST PATCHY LIGHT FOG.

LONG TERM... UPPER LEVEL TROUGH TO THE WEST LOOKS TO PINCH OFF ON
THE SOUTHERN SIDE OVER TEXAS AND MOVE EAST THRU FRIDAY. THIS SHIFT
TO THE EAST WILL USHER IN MORE MOISTURE AND INCREASINGLY BUOYANT
CONDITIONS WHICH WILL BE MORE CONDUCIVE FOR SHOWER AND THUNDERSTORM
DEVELOPMENT. SO HAVE KEPT PREVIOUS FCST 20 TO TO 40 PERCENT POPS
DURING THAT TIME FRAME. THIS SLIGHTLY WET PATTERN WILL PERSIST INTO
THE WEEKEND WITH CONTINUED DAYTIME HEATING AND LACK OF HIGH PRESSURE
SUBSIDENCE. COULD EVEN SEE COVERAGE UP TO 50 PERCENT BY SUNDAY.

MEFFER

AVIATION...

SCATTERED CUMULUS FIELD ACROSS THE AREA WITH BASES FL035-FL040.
ANTICIPATE VFR CONDITIONS FOR MUCH OF THE PERIOD. COULD SEE SOME
MVFR VISIBILITIES AROUND SUNRISE FOR A FEW HOURS AT KHUM...KMCB AND
KHDC. ANY CONVECTIVE THREAT WEDNESDAY LIKELY TO BE AFTER 18Z. ONLY
TERMINAL WHERE THREAT MAY BE HIGH ENOUGH FOR A MENTION THIS FAR OUT
IN FORECAST WOULD BE KHUM. 35


MARINE...

RELATIVELY BENIGN CONDITIONS FOR THE NEXT SEVERAL DAYS WITH A WEAK
PRESSURE PATTERN CONTROLLING THE WEATHER. WINDS GENERALLY LESS THAN
10 KNOTS WITH SEAS 2 FEET OR LESS. SCATTERED CONVECTION POSSIBLE
JUST ABOUT EVERY DAY OF FORECAST AFTER TODAY. THIS ACTIVITY MAY
PRODUCE WIND GUSTS TO 30 KNOTS OR BETTER AT TIMES AS IT MOVES OUT OF
THE GULF. 35


DECISION SUPPORT...
DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  94  72  91  72 /  10  10  20  10
BTR  93  74  92  72 /  20  10  20  20
ASD  93  72  91  73 /  10  10  20  20
MSY  92  77  91  76 /  10  10  30  20
GPT  92  75  90  75 /  10  10  20  20
PQL  93  73  92  74 /  10  10  20  20

&&

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

$$


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