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

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110
FXUS64 KLIX 020109
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
809 PM CDT MON SEP 1 2014

...SOUNDING DISCUSSION...

A VERY MOIST ATMOSPHERIC PROFILE WAS SAMPLED THIS EVENING AND THE
TEMPERATURE GENERALLY FOLLOWING MOIST ADIABATS FROM ABOUT 800MB TO
THE TROPOPAUSE. A PRECIPITABLE WATER OF 2.35 INCHES IS NEARING THE
99TH PERCENTILE FOR THIS TIME OF YEAR. THERE REMAINS A FAIR AMOUNT
OF INSTABILITY WITH MLCAPES AROUND 1200 J/KG THIS EVENING. THERE
ARE JUST A FEW THUNDERSTORMS REMAINING AT THIS TIME AND THESE WILL
DISSIPATE DURING THE REMAINDER OF THE EVENING. WINDS FROM THE
SURFACE TO 700MB WERE BETWEEN 15 AND 20 KNOTS FROM THE SOUTH.
WINDS IN THE MID-LEVELS AND UPPER LEVELS /700MB-100MB/ WERE FROM
THE WEST AT AROUND 10 KNOTS AND IN THE STRATOSPHERE THE WINDS WERE
FROM THE EAST.

00Z BALLOON INFO: A ROUTINE AND SUCCESSFUL FLIGHT THIS EVENING.
THE BALLOON TERMINATED AT A HEIGHT OF 21.2 MILES ABOVE THE
GROUND AND WAS 24 MILES DOWNRANGE OVER THE NORTHWEST PART OF LAKE
PONTCHARTRAIN.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 325 PM CDT MON SEP 1 2014/

SHORT TERM...

A LINGERING INVERTED TROUGH OVER THE LOWER MISSISSIPPI VALLEY WILL
CONTINUE TO SHEAR OUT AS IT MOVES INLAND TONIGHT. BY TOMORROW...A
STRENGTHENING UPPER LEVEL RIDGE AXIS WILL BUILD OVER THE FORECAST
AREA. THIS RIDGING WILL CONTINUE TO INTENSIFY INTO WEDNESDAY.
FURTHER DOWN IN THE ATMOSPHERE...CONTINUED ONSHORE FLOW WILL
DOMINATE IN THE LOW TO MID-LEVELS. THIS ONSHORE FLOW WILL KEEP A
DEEP LAYER OF GULF MOISTURE OVER THE AREA. AS A RESULT...PW VALUES
WILL REMAIN IN EXCESS OF 2 INCHES THROUGH MIDWEEK. EVEN WITH SOME
INCREASED SUBSIDENCE AND WARMING ALOFT...THERE SHOULD BE ENOUGH
INSTABILITY DURING THE AFTERNOON HOURS TO SPARK OFF SCATTERED
CONVECTION ALONG SEABREEZE AND OUTFLOW BOUNDARIES. CONVECTION WILL
TEND TO DEVELOP INITIALLY OFFSHORE DURING THE EARLY MORNING HOURS
AND THEN BEGIN TO PUSH INLAND AS THE SEABREEZE FORMS. HAVE WENT
WITH CHANCE POPS FOR THE AFTERNOON HOURS...AND SLIGHT CHANCE POPS
IN THE MORNING AND EVENING HOURS. TEMPERATURES WILL BE NEAR
SEASONAL NORMS IN THE LOWER 90S DURING THE AFTERNOON AND THE
MIDDLE 70S AT NIGHT.

LONG TERM...

THERE WILL BE LITTLE CHANGE IN THE PATTERN GOING INTO THE LATTER
HALF OF THE WEEK. A BROAD UPPER LEVEL RIDGE WILL DOMINATE THE
REGION ALOFT...AND CONTINUED ONSHORE FLOW WILL DOMINATE IN THE LOW
TO MID-LEVELS. AS A RESULT...SCATTERED DIURNALLY INDUCED
CONVECTION WILL BE POSSIBLE EACH DAY THROUGH SATURDAY WITH
COVERAGE DECREASING DURING OVERNIGHT AND MORNING HOURS. HIGHS WILL
REMAIN CLOSE TO SEASONAL NORMS IN THE LOWER 90S AND OVERNIGHT LOWS
WILL COOL INTO THE LOWER TO MIDDLE 70S EACH NIGHT.

THE RIDGE WILL FINALLY BEGIN TO PULL TO THE WEST AND BECOME MORE
CENTERED OVER THE SOUTHERN PLAINS ON SUNDAY. AS THIS OCCURS...AN
UPPER LEVEL TROUGH MOVING THROUGH THE GREAT LAKES STATES WILL
DRIVE A WEAK BACK DOOR FRONT TOWARD THE FORECAST AREA. THIS FRONT
WILL STRUGGLE TO REACH THE REGION...AND SHOULD WASH OUT SOMEWHERE
OVER MISSISSIPPI AND ALABAMA. OVERALL...CONVECTIVE COVERAGE MAY BE
A BIT HIGHER ON SUNDAY DUE TO THE PROXIMITY OF THE WEAK FRONTAL
BOUNDARY...BUT STILL ONLY EXPECT SCATTERED COVERAGE AT BEST. THE
CONVECTION MAY ALSO LAST LONGER INTO THE EVENING HOURS AS SLIGHTLY
ENHANCED LIFT ALLOWS THE UPDRAFTS TO LINGER PAST SUNSET.

AVIATION...

SCATTERED TO NUMEROUS THUNDERSTORMS WILL RESULT IN INTERMITTENT
IMPACTS ACROSS TERMINALS TODAY. WILL LEAVE VCTS IN PLACE THIS AFTN
AND COULD ADD TEMPOS AT TIMES FOR LOWER VIS DURING BRIEF HEAVY
RAINFALL EVENTS. VFR CIGS SHOULD RETURN LATER THIS EVENING AND MOST
OF THE OVERNIGHT PERIOD. IFR CONDITIONS COULD DEVELOP AT MCB DUE TO
LOW CIGS FOR A FEW HOURS TUESDAY MORNING AND A FEW OTHER AIRPORTS
MAY LOWER TO MVFR. HIGHER RAIN CHANCES EXPECTED AGAIN TOMORROW.

MEFFER

MARINE...

A TIGHTENING OF THE PRESSURE GRADIENT THAT BROUGHT WINDS INTO THE
EXERCISE CAUTION RANGE OVER OFFSHORE WATERS IS BEGINNING TO RELAX.
SUBSEQUENTLY....SOUTHEAST WINDS HAVE BEGUN TO WEAKEN AND ARE NOW
AROUND 10 TO 15 KNOTS AT THE HIGHEST. SEAS HAVE FALLEN SLIGHTLY AS
WELL WITH PEAKS NEAR 4 FEET FOR SIGNIFICANT WAVE HEIGHTS.AS THE
INVERTED TROUGHS MOVE WEST OF THE MARINE AREA...SOUTHEAST WINDS
SHOULD EASE BACK TO AROUND 10 KNOTS OR LESS ON TUESDAY...THEN EAST
TO SOUTHEAST AROUND 10 KNOTS WEDNESDAY THROUGH FRIDAY. SEAS SHOULD
SUBSIDE SLOWLY BACK TO 2 TO 4 FEET TUESDAY MORNING AND 1 TO 3 FEET
WEDNESDAY THROUGH FRIDAY.

MEFFER

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  75  93  73  93 /  20  40  20  40
BTR  76  93  74  94 /  20  40  20  40
ASD  77  92  76  93 /  20  40  20  40
MSY  78  91  77  91 /  20  40  20  40
GPT  78  91  77  92 /  20  40  20  40
PQL  76  92  74  93 /  20  30  20  40

&&

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

$$








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