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

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511
FXUS64 KLIX 130944
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
444 AM CDT MON OCT 13 2014

.SHORT TERM...
THE MAIN CONCERNS WILL DEFINITELY BE IN THE SHORT-TERM AS A
VIGOROUS FALL STORM IS CURRENTLY UNDERWAY AND EVOLVING OVER THE
LOWER PLAINS STATES. A WELL DEFINED SQUALL LINE HAS DEVELOPED FROM
NORTHERN ARKANSAS AND EXTENDING TO SOUTH OF THE DALLAS-FORT WORTH
METROPLEX THIS MORNING. THE EASTWARD PROGRESSION IS MEASURED AT 25
KNOTS AND CURRENTLY OUT-RUNNING THE UPPER SUPPORT. THE LOWER LOBE
OF UPPER TROUGH GAINS AMPLITUDE THROUGHOUT THE DAY AND BECOMES
NEUTRALLY TILTED BY THIS EVENING UPON ARRIVAL INTO THE FORECAST
AREA. SEVERAL CONVECTIVE WATCHES AND A FEW WARNINGS ALREADY ARE IN
PLACE AHEAD OF THIS SQUALL AND ADDITIONAL ISSUANCES CAN BE
EXPECTED EASTWARD THROUGH THIS EVENING. GIVEN FORWARD
PROGRESS...BEST ARRIVAL TIMING APPEARS TO BE KBTR AROUND 7
PM...KMCB 8 PM...KHDC 830 PM...KASD/KMSY 930 PM...KGPT/KBIX 11
PM...KPQL AROUND MIDNIGHT. CHAP GUIDANCE OFF THE GFS IS SHOWING
SOME FAST TIMING ISSUES BUT THE POTENTIAL IMPACTS ARE ACCEPTABLE.
KBTR/KMCB MODEL SOUNDINGS ARE INDICATING HIGH END EF1 TORNADO
POTENTIAL...GUSTS TO 71 MPH. POINTS EAST ARE INDICATED TO BE JUST
ABOVE SEVERE THRESHOLDS AND POINTS SOUTH OF THE LAKE WERE
INDICATED TO BE SUB-SEVERE. PRECIPITATION TOTALS FROM CHAP WERE
CLOSE TO 2 INCHES OVER A SHORT DURATION BETWEEN 00Z-06Z. BY
COMPARISON... THE NAM MODEL GUIDANCE MAINTAINED SUB-SEVERE
POTENTIALS AT ALL LOCATIONS AND APPEARS TO BE UNDERPERFORMING WITH
THIS SYSTEM. THE GFS BASED GUIDANCE WILL BE THE BASIS FOR HWO AND
CONSISTENT WITH SPC OUTLOOK GUIDANCE. WE DO ANTICIPATE MOST OR ALL
OF THE FORECAST AREA TO BE PLACE UNDER A WATCH AT SOME POINT MID
TO LATE AFTERNOON HOURS.

SHARP UPPER TROUGH AXIS SHOULD PASS TO THE EAST OF THE FORECAST
AREA NEAR DAYBREAK TUESDAY WITH HIGH PRESSURE THEN BUILDING INTO
THE AREA. SEVERE STORM THREAT WILL END WITH FRONTAL PASSAGE FROM
WEST TO EAST. DRIER CONDITIONS MOVE INTO THE AREA FOR TUESDAY
ALONG WITH DECENT COLD AIR ADVECTION THAT NEUTRALIZES LATER
TUESDAY.

.LONG TERM...
THE EXTENDED PORTION OF THIS PACKAGE IS ESSENTIALLY A TEMPERATURE
FORECAST WITH DRY CONDITONS EXPECTED INTO NEXT WEEKEND. A STEADY
WARMING TREND ONSETS WEDNESDAY ONWARD AND MOISTURE WILL GRADUALLY
INCREASE BY NEXT WEEKEND. 24/RR

&&

.AVIATION...
A SCATTERED TO BROKEN CLOUD DECK RANGING AROUND 2000-2500 FEET WILL
KEEP MVFR CONDITIONS IN PLACE AT ALL OF THE TERMINALS THROUGH THE
MORNING HOURS.  AFTER 18Z...SOUTHERLY WINDS WILL INCREASE TO AROUND
15 KNOTS WITH HIGHER GUSTS AS A STRONG LOW LEVEL JET BEGINS TO MOVE
INTO THE LOWER MISSISSIPPI VALLEY.  AS SHEAR AND OVERALL INSTABILITY
INCREASES...SCATTERED STRONG CONVECTION WILL BEGIN TO DEVELOP OVER
THE AREA.  PERIODS OF IFR AND POSSBILY LIFR CONDITIONS WILL IMPACT
THE TERMINALS AS THIS CONVECTION MOVES THROUGH.  STRONG WIND GUSTS
WILL ALSO BE POSSIBLE.  A SQUALL LINE WILL THEN ACCOMPANY A COLD
FRONT AS IT SWEEPS THROUGH THE AREA BETWEEN 00Z AND 10Z TONIGHT.
THE LINE SHOULD IMPACT AREAS AROUND BTR BETWEEN 00Z AND 04Z.
MCB...HDC...MSY...NEW...AND HUM WILL BE IMPACTED BETWEEN 02Z AND
06Z.  ASD AND GPT WILL SEE IMPACTS FROM AROUND 06Z THROUGH 10Z.
VERY STRONG WIND GUSTS AND SOME HAIL WILL BE POSSIBLE AS THIS LINE
OF STORMS MOVES THROUGH TONIGHT. 32

&&

.MARINE...
STRENGTHENING ONSHORE FLOW IN ADVANCE OF DEEPENING STORM SYSTEM IN
THE PLAINS PROMPTED THE ISSUANCE OF SMALL CRAFT ADVISORY FOR
TODAY...THOUGH WIND CRITERIA MAY BE MARGINAL THIS MORNING. MAIN
CONCERNS WILL BE EVENTUAL SQUALL LINE DEVELOPMENTS BY THIS EVENING
THAT WILL LIKELY GENERATE GUSTS 35-50 KNOTS OVER THE GULF WATERS
OVERNIGHT. AS COLD AIR ADVECTION OVERTAKES THE NORTH GULF TOWARDS
TUESDAY MORNING...WEST AND NORTHWEST WINDS WILL CONTINUE TO BE
GUSTY JUST BELOW GALE FORCE TUESDAY MORNING BEFORE COLD AIR
ADVECTION ABATES LATE MORNING FROM WEST TO EAST. WIND AND SEA
CONDITIONS SHOULD SETTLE TO LESSER LEVELS LATE TUESDAY AND PREVAIL
THROUGH THE REMAINDER OF THE WEEK. THERE MAY BE SOME DRAINAGE WIND
ENHANCEMENTS OVER MISSISSIPPI SOUND TUESDAY NIGHT AND EARLY
WEDNESDAY MORNING BUT THIS SHOULD REMAIN CONFINED TO THE NEAR
SHORE AREAS FOR THE MOST PART. 24/RR

&&

.DECISION SUPPORT...
DSS CODE...ORANGE.
DEPLOYED...NONE.
ACTIVATION...AMATEUR RADIO NETWORK AND HIGH IMPACT DESK THIS PM.
ACTIVITIES...SLURRY SUPPORT...MONITORING SEVERE WEATHER.

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  85  59  74  51 /  70 100  10   0
BTR  86  58  74  51 /  80 100  10   0
ASD  85  62  75  52 /  60  90  10   0
MSY  86  65  74  59 /  60  90  10   0
GPT  82  67  76  52 /  70  90  20   0
PQL  83  67  75  53 /  70  90  20   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 11 AM TUESDAY FOR THE FOLLOWING
     ZONES: BRETON SOUND...CHANDELEUR SOUND...COASTAL WATERS
     FROM BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER OUT 20 NM...COASTAL WATERS FROM PASCAGOULA MS TO
     STAKE ISLAND LA FROM 20 TO 60 NM...COASTAL WATERS FROM
     PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM...COASTAL WATERS
     FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER FROM 20 TO 60
     NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA
     RIVER OUT 20 NM...COASTAL WATERS FROM STAKE ISLAND LA TO
     THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60
     NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO 60
     NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM...LAKE
     BORGNE...LAKE PONTCHARTRAIN AND LAKE MAUREPAS...AND
     MISSISSIPPI SOUND.

MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 11 AM TUESDAY FOR THE FOLLOWING
     ZONES: BRETON SOUND...CHANDELEUR SOUND...COASTAL WATERS
     FROM BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER OUT 20 NM...COASTAL WATERS FROM PASCAGOULA MS TO
     STAKE ISLAND LA FROM 20 TO 60 NM...COASTAL WATERS FROM
     PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM...COASTAL WATERS
     FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER FROM 20 TO 60
     NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA
     RIVER OUT 20 NM...COASTAL WATERS FROM STAKE ISLAND LA TO
     THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60
     NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO 60
     NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM...LAKE
     BORGNE...LAKE PONTCHARTRAIN AND LAKE MAUREPAS...AND
     MISSISSIPPI SOUND.

&&

$$

24/RR
32





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