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

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194
FXUS64 KLIX 201721
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1121 AM CST THU NOV 20 2014


.AVIATION...
VFR CONDITIONS ARE EXPECTED TO HOLD THROUGH AT LEAST 18Z FRIDAY
WITH SOME DETERIORATION IN CONDITIONS TO ONSET LATER FRIDAY NIGHT
BEYOND THIS TAF PACKAGE ISSUANCE. 24/RR

&&

.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT. ASSESSING COASTAL FLOOD POTENTIAL FOR
          SATURDAY...SEVERE WEATHER POTENTIAL FOR SATURDAY NIGHT AND
          SUNDAY MORNING.

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.

&&

.PREV DISCUSSION... /ISSUED 350 AM CST THU NOV 20 2014/

SHORT TERM...
BROAD LONGWAVE TROUGH THAT HAS BEEN ENCOMPASSING A MAJORITY OF THE
EASTERN CONUS HAS FINALLY BEGUN TO LIFT FURTHER AWAY FROM THE AREA.
SURFACE HIGH PRESSURE CENTERED EAST OF THE CWA WILL BEGIN TO FADE
AND BE ABSORBED BY A DEEPER RIDGE TO THE NORTH OF IT. THIS WILL KEEP
WINDS SOUTH/SOUTHEAST THROUGHOUT THE DAY WHICH WILL KEEP DEWPOINTS
ON AN UPWARD TREND. THIS IN COMBINATION WITH INCREASING 500MB
HEIGHTS FROM THE UPPER TROUGH SHIFTING POSITION AND INCREASING
MOISTURE WILL RESULT IN AIR MASS MODIFICATION WITH MILDER TEMPS
EXPECTED. HIGHS SHOULD TOP OUT IN THE MID TO UPPER 60S WHICH IS
STILL BELOW CLIMATOLOGICAL NORMAL. THIS WARMING TREND WILL CONTINUE
THROUGHOUT THE REST OF THE WEEK AS THE UPPER LEVEL TROUGH LIFTS
NORTHEAST AND WEAK UPPER RIDGING BUILDS.

LONG TERM...
THE MAIN FOCUS OF THE EXTENDED FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER SATURDAY AFTERNOON AND THROUGH THE OVERNIGHT PERIOD.
COLUMN MOISTURE WILL BE ON THE INCREASE WITH SIGNIFICANCE SATURDAY
AS WITH STRONG ONSHORE FLOW WELL ESTABLISHED WITH MODEL SOUNDINGS
SHOWING PRECIP WATER COMING UP TO OVER 1.5 INCHES LATE IN THE DAY.
THE UPPER TROUGH WILL BE SWINGING ACROSS TEXAS AND BECOMING
NEGATIVELY TILTED WHILE IT DOES SO SATURDAY EVENING. MODEL SOUNDINGS
SHOW MID LEVEL COOLING AND LOW LEVEL WARMING WHICH WILL STEEPEN MID
LEVEL LAPSE RATES AND INCREASE INSTABILITY. BULK SHEAR OF 70+KTS
WHICH IS NEAR THE MAX FOR THIS TIME OF YEAR STILL LOOKS TO BE ON TAP
WHICH COMBINED WITH CAPE OF 500-1000 J/KG PRODUCE THE POTENTIAL FOR
SOME SEVERE THUNDERSTORMS. ONE POSSIBLE LIMITING FACTOR WILL BE THE
MARINE LAYER ALONG THE COAST. RECENT STRONG COLD FRONTS HAVE DROPPED
NEARSHORE WATERS TO BELOW 60 DEGREES FOR PORTIONS OF THE LA COAST
WEST OF LAFOURCHE PARISH...LAKE PONTCHARTRAIN...AND THE SOUNDS. OTHER
AREAS...ESP SOUTH OF THE NEW ORLEANS METRO...STILL HAS WATER TEMPS
NEAR 70 DEGREES. SO COULD HAVE INTERMITTENT SHADOWING OR WEAKENING
OF STORMS AS THE PASS FROM WEST TO EAST ACROSS THE CWA. THIS ISSUE
SHOULDNT BE AS MUCH OF AN ISSUE FURTHER INLAND. CONDITIONS SHOULD
RAPIDLY IMPROVE FROM WEST TO EAST SUNDAY MORNING AFTER SUNRISE.

THE REMAINDER OF THE WEEK SHOULD BE DRY AND COOLER AS A DEEP TROUGH
SENDS ANOTHER STRONG COLD FRONT THROUGH THE AREA MONDAY AND THEN
AGAIN TUESDAY NIGHT WITH A REINFORCING BOUNDARY.

MEFFER

MARINE...HIGH PRESSURE CURRENTLY CNTRD OVER THE REGION WILL QUICKLY
EVACUATE TO THE EAST LATE TODAY AND MORE SO TONIGHT. THIS WILL LEAD
TO ERLY WINDS DURING THE DAY SLOWLY BECOMING SERLY EARLY FRI
MORNING. WINDS WILL ALSO BE ON THE INCREASE AS THE PRESSURE GRADIENT
TIGHTENS BETWEEN THE HIGH AND A DEVELOPING SFC LOW IN WEST TX. IT IS
HIGHLY LIKELY THAT A SCY WILL BE NEEDED DURING THE DAY FRI AS THE
PRESSURE GRADIENT CONTINUES TO TIGHTEN(4-5MB DIFFERENCE OVER THE
CWA). AS OUR DYNAMIC SYSTEM DEVELOPS FRI AND INTO SAT THE LL WINDS
WILL RESPOND AND STRONG WIND GUSTS COULD MAKE IT DOWN TO THE WATER.
IN ADDITION THE PERSISTENT ERLY TO SERLY FLOW BEGINNING TODAY AND
THROUGH SAT EVENING WILL LEAD TO A DECENT FETCH WITH HIGH SEAS.
WINDS WILL BECOME SWRLY SUN AND REMAIN THAT WAY UNTIL LATE MON WHEN
THE NEXT COLD FRONT FINALLY MOVES THROUGH. /CAB/

AVIATION...OVERALL VFR CONDITIONS WILL PERSIST THROUGH THE FCST.
THE ONLY EXCEPTION COULD BE TEMPO MVFR VSBYS AT THE NORMAL PROBLEM
SITES...MCB...ASD...GPT...AND HDC. /CAB/

.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  65  45  68  48 /  10  10  10   0
BTR  68  49  71  51 /   0  10  10   0
ASD  67  47  70  51 /   0  10  10   0
MSY  68  54  70  58 /   0  10  10   0
GPT  65  48  68  53 /   0  10  10   0
PQL  65  44  68  48 /   0  10  10   0

&&

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

$$

24/RR






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