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

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884
FXUS64 KLIX 181719
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1119 AM CST TUE NOV 18 2014

.AVIATION...
LAST VESTIGES OF HIGH CLOUDS ARE THINNING STEADILY WITH VFR CAVOK
CONDITIONS EXPECTED FOR NEXT 24-30 HOURS. 24/RR

&&


.PREV DISCUSSION... /ISSUED 701 AM CST TUE NOV 18 2014/

..SOUNDING DISCUSSION...

AN UNSEASONABLY COLD SOUNDING WITH TEMPERATURES LOWER /COLDER/
THAN YESTERDAY AT EVERY LEVEL. TEMPERATURES BELOW 13000 FEET ARE
AT LEAST 6 DEGREES CELSIUS LOWER THAN YESTERDAY AT THIS TIME!
IT IS ALSO A VERY DRY SOUNDING THANKFULLY WITH PRECIPITABLE WATER
VALUES NEAR THE MINIMUM VALUE FOR THIS LAUNCH DATE/TIME. THE
MOISTURE WE DO IS MAINLY BETWEEN 20000 AND 30000 FEET. WINDS WERE
TYPICAL OF A COLD ADVECTION REGIME WITH WINDS FROM THE NORTH NEAR
THE SURFACE AND SHIFTING TO THE NORTHWEST AND THEN WEST BY ABOUT
13000 FEET. ABOVE 13000 FEET...WINDS WERE PRIMARILY FROM THE
SOUTHWEST. A PEAK WIND OF 143 KNOTS WAS LOCATED AT 40300 FEET.

12Z BALLOON INFO: NO ISSUES WITH THE FLIGHT THIS MORNING...WHICH
REACHED A HEIGHT OF 19 MILES ABOVE THE GROUND BEFORE BURSTING OVER
BAY MINETTE AL 127 MILES DOWNRANGE FROM THE LAUNCH SITE. THE
FLIGHT LASTED 94 MINUTES.

ANSORGE

PREV DISCUSSION... /ISSUED 409 AM CST TUE NOV 18 2014/

SHORT TERM...
BROAD LONGWAVE TROUGH CONTINUES TO DIG DOWN ACROSS THE EASTERN TWO
THIRDS OF THE COUNTRY. LOCALLY THIS WILL KEEP STRONG COLD AIR
ADVECTION GOING AND THUS ANOTHER UNSEASONABLY COLD DAY ON TAP. HIGHS
WILL BE 20 TO 25 DEGREES BELOW NORMAL WITH ONLY LOCATIONS NEAR THE
COAST BEING THE ONLY ONES TO SEE 50 DEGREE TEMPERATURES. THE
OVERNIGHT PERIOD WILL ONCE AGAIN BE THE TOUGHEST PART OF THE SHORT
TERM FORECAST. LATEST 11-3.9U IMAGERY SHOWS A WIDE SWATH OF HIGH
LEVEL CLOUDS MOVING IN ACROSS THIS AREA WHICH WILL LIKELY LIMIT MUCH
MORE COOLING FOR AREAS NW OF A HUM TO ASD LINE AND THUS FCST LOWS
PROBABLY WONT BE MET. THE QUESTION NOW IS WHAT ABOUT TONIGHT. GFS
MODEL SOUNDINGS DO SHOW THIS CLOUD DECK IN PLACE THIS MORNING AND
HAVE IT DISSIPATING LATE MORNING AND NOT RETURNING OVERNIGHT. IN
ADDITION...BOUNDARY LAYER WINDS WILL BE ABOUT 15 KNOTS WEAKER AND
ACTUALLY DECOUPLE BY 12Z. SO THINKING IS THAT THERE "SHOULD" BE MORE
COOLING DURING THE OVERNIGHT PERIOD. DID NOT GO AS COLD AS MAV/MET
GUIDANCE BUT CLOSER TO BLENDED ENSEMBLES. THIS PUTS MUCH OF THE CWA
NORTH OF INTERSTATE 12 AROUND THE MID 20S. WILL LET DAY SHIFT GET
ONE MORE LOOK AT THIS DUE TO THE BORDERLINE NATURE OF THE EVENT
BEFORE ISSUING A HARD FREEZE WARNING.

LONG TERM...
THE FOLLOWING DAYS THIS WEEK WILL BE PART OF A WARMING TREND AS THE
TROUGH LIFTS NORTHEAST AND THUS ALLOWS TEMPERATURES TO MODIFY. MID
60 HIGHS SHOULD BE BACK BY THURSDAY. MAIN FOCUS BEYOND THAT WILL BE
THE POTENTIAL FOR SEVERE WEATHER SATURDAY NIGHT. MOISTURE WILL BE ON
THE INCREASE BEGINNING FRIDAY SURFACE RIDGE SLIDING EAST AND
SOUTHEAST FLOW BECOMING WELL ESTABLISHED. UPPER TROUGH WILL BE
SWINGING ACROSS THE CENTRAL PLAINS AND BECOME NEGATIVELY TILTED
WHILE IT DOES SO SATURDAY EVENING. MODEL SOUNDINGS SHOW MID LEVEL
COOLING AND STEEPENING LAPSE RATES AS THE COLD FRONT ASSOCIATED WITH
THIS SYSTEM APPROACHES. THIS WILL INCREASE INSTABILITY AND WHEN
COMBINED WITH BULK SHEAR OF 70+KTS WHICH IS NEAR THE MAX FOR THIS
TIME OF YEAR...SHOULD HAVE SOME SEVERE THUNDERSTORMS ROLLING THROUGH
THE AREA. WILL BE MENTIONING POSSIBLE SEVERE IN THE HWO THIS
MORNING. TIMING OF THIS SYSTEM IS SLIGHTLY FASTER THAN PREVIOUS
MODEL SOLUTIONS...SO HAVE ADJUSTED POPS ACCORDINGLY.

MEFFER

AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. CLEAR SKIES AND
EXCELLENT VSBYS WILL PREVAIL. SOME STRONGER AND OCCASIONALLY GUSTY
NORTH WINDS NEAR THE TIDAL LAKES AND COAST WILL GRADUALLY SUBSIDE
THIS AFTERNOON. 18

MARINE...
NORTH WINDS ARE EXPECTED TO DECREASE TODAY...WILL CARRY SCA THROUGH
TODAY WITH NEAR SHORE WATERS DROPPING OFF FIRST. HIGH PRESSURE OVER
EAST TEXAS WILL SLIDE EAST OVER THE FORECAST AREA TUESDAY AND
TUESDAY NIGHT. SURFACE WINDS WILL FINALLY COLLAPSE OVER NEAR SHORE
WATERS BUT REMAIN MODERATE WELL OFFSHORE TONIGHT AND WEDNESDAY. A
PACIFIC SYSTEM WILL SWEEP ACROSS THE LOWER MISSISSIPPI VALLEY AND
NORTH CENTRAL GULF SATURDAY. STRONG ONSHORE FLOW MAY DEVELOP AHEAD
OF THE ASSOCIATED FRONTAL BOUNDARY AS EARLY AS FRIDAY NIGHT AND
CONTINUING THROUGH SATURDAY. AS A RESULT...SMALL CRAFT ADVISORIES
MAYBE ISSUED DURING THIS TIME. 18

DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT.
             MONITORING POTENTIAL FOR ISOLATED SEVERE WEATHER THIS
             AFTERNOON THROUGH TONIGHT.

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  24  57  37 /   0   0   0   0
BTR  47  27  59  39 /   0   0   0   0
ASD  47  26  58  38 /   0   0   0   0
MSY  48  36  58  46 /   0   0   0   0
GPT  47  26  54  41 /   0   0   0   0
PQL  47  23  55  35 /   0   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM TUESDAY FOR THE FOLLOWING ZONES:
     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...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM TUESDAY FOR THE FOLLOWING ZONES:
     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...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

&&

$$








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