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

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015
FXUS64 KLIX 260108
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
808 PM CDT FRI JUL 25 2014

...SOUNDING DISCUSSION...
A SUCCESSFUL 00Z BALLOON LAUNCH THIS EVENING THAT REACHED A HEIGHT
OF 21 MILES ABOVE THE GROUND AND BURST OVER THE SOUTHWEST PORTION
OF LAKE MAUREPAS. A RATHER MOIST ATMOSPHERIC COLUMN UP TO ABOUT
525MB AFTER WHICH DRIER AIR IS ENCOUNTERED. THE 750 TO 650MB LAYER
HAS MOISTENED CONSIDERABLE FROM THIS MORNING/S SOUNDING AS THE
DRIER AIR IS BEING PUSHED OFF TO THE WEST PER WV IMAGERY AND
LINGERING CLOUDS FROM THIS AFTERNOON/S THUNDERSTORMS MOVED OVER
THE LAUNCH SITE. THE TEMPERATURE AT THE SURFACE IS COMPARABLE TO 24
HOURS AGO...THEN GENERALLY 1 OR 2 DEGREES HIGHER /WARMER/ UP TO
ABOUT 600MB. PRECIPITABLE WATER VALUES REMAIN ABOVE SEASONAL
VALUES AT OVER 2 INCHES. THERE REMAINS PLENTY OF INSTABILITY /MLCAPE
1731 J/KG/ AND WEAK 0-6KM SHEAR WHICH HAS ALLOWED FOR TYPICAL
SUMMERTIME SCATTERED THUNDERSTORMS OVER SOUTHEAST LOUISIANA AND
SOUTHWEST MISSISSIPPI. WINDS WERE LIGHT AND FROM THE SOUTHWEST AT
THE SURFACE AND THEN VEERED TO NORTHEASTERLY ABOVE 450MB. A WIND
SPEED MAX OF 45 KNOTS WAS LOCATED 7.3 MILES ABOVE THE GROUND.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 352 PM CDT FRI JUL 25 2014/

SHORT TERM...
A RATHER FLAT PRESSURE GRADIENT OVER THE REGION HAS WINDS VARYING
FROM SOUTHWESTERLY AROUND A HIGH CENTERED OVER THE MIDDLE
GULF...TO NORTHWESTERLY IN INTERIOR SECTIONS FROM CONTINENTAL HIGH
PRESSURE OVER UPPER MISSISSIPPI. THERE IS A CONVERGENCE ZONE OF
SORTS OVER SOUTHEAST MISSISSIPPI AND NORTH OF THE TIDAL LAKES TO
AID FOCUS FOR LAKE BREEZE CONVECTION THIS AFTERNOON. WITH VERY
LITTLE STEERING...MOST OF THE STORMS ARE RUNNING ON PROPAGATION
ALONG THE CONVERGENCE BAND BUT BECOMING OUTFLOW DOMINATED RATHER
QUICKLY. THE FEW CLUSTER OF CELLS ON THE SCOPE SHOULD DISSIPATE BY
SUNSET THIS EVENING. WITH BOUNDARY LAYER DECOUPLING
OVERNIGHT...MAY SEE SOME MINOR SHALLOW FOG DEVELOPMENTS BY
DAYBREAK TO BURN OFF BY MID-MORNING. CONVECTIVE COVERAGE ON
SATURDAY SHOULD REMAIN BELOW NORMAL AND FOCUSED ON LAKE AND GULF
BREEZE BOUNDARIES. COVERAGE SHOULD ONCE AGAIN BE ISOLATED AND
SHORT-LIVED IN NATURE.

LONG TERM...
THE MAIN CONCERNS WILL REMAIN WITH THE EXPECTATIONS OF A COLD
FRONT ADVANCING SOUTHWARD AS DEEP TROUGHING TAKES PLACE OVER THE
EASTERN UNITED STATES. THE FRONT IS STILL INDICATED BY THE MODELS
TO MOVE THROUGH ACCOMPANIED BY THUNDERSTORMS MONDAY NIGHT THROUGH
TUESDAY MORNING. IT IS STILL UNCERTAIN IF THE FRONT WILL ACTUALLY
CLEAR THE COAST BEFORE BECOMING STATIONARY THOUGH CONVECTION MAY
INDUCE IT SOUTHWARD INITIALLY BEFORE BECOMING QUASI-STATIONARY
TUESDAY INTO WEDNESDAY. THE PRESENCE OF THE FRONTOLYTIC BOUNDARY
WILL SERVE TO EITHER DISRUPT THE LAND-GULF BREEZE CYCLE OR
ENHANCE THE GULF BREEZE ASPECT FOR SYNOPTIC SCALE AUGMENTATION OF
CONVERGENT LOW LEVEL WINDS. THERE IS A BIT OF A TIMING
DISAGREEMENT BETWEEN THE GFS AND ECMWF...BUT BOTH MODELS DO
INDICATE AN IMPULSE EVENTUALLY RUNNING ALONG THE FRONTOLYTIC
BOUNDARY TO INCREASE RAIN COVERAGE AND EFFICIENCY MIDDLE OF NEXT
WEEK. THE GFS IS MORE AMBITIOUS WITH PUSHING THE FRONT WELL INTO
THE GULF...WHILE THE ECMWF KEEPS IT CLOSER TO THE FORECAST
AREA...THEREBY POSING THE GREATER RISK FOR HEAVY RAINS NEXT WEEK.
AT THIS TIME...INDICATED A BLENDED FORECAST THAT ALLOWS FOR
ADJUSTMENTS UPWARD NEXT WEEK BUT CONCEDING THE FRONT MAY HAVE A
CHANCE TO REACH FARTHER SOUTH THAN CURRENTLY BELIEVED.

AVIATION...
HAVE KEPT THE MENTION OF CONVECTION OUT OF THE FORECAST FOR THE
AFTERNOON HOURS TODAY AND TOMORROW AS COVERAGE IS ISOLATED AT
BEST. A SCATTERED TO BROKEN CU FIELD RUNNING AROUND 4000 FEET WILL
LINGER THROUGH 00Z...BUT SHOULD DISSIPATE SHORTLY AFTER SUNSET.
THERE MAY BE SOME LIGHT FOG FORMATION AT SEVERAL OF THE TERMINALS
AROUND 10Z TO 13Z...WHICH COULD PRODUCE A PERIOD OF MVFR
VISIBILITY RESTRICTIONS. THIS FOG SHOULD QUICKLY CLEAR ONCE THE
WEAK LOW LEVEL INVERSION LIFTS. OVERALL...EXPECTING TO SEE VFR
CONDITIONS PREVAIL AT ALL OF THE TERMINALS. 32

MARINE...
LIGHT TO MODERATE SOUTHWEST WINDS AROUND THE NORTHERN PERIPHERY OF
HIGH PRESSURE CENTERED OVER THE MIDDLE GULF IS EXPECTED TO PREVAIL
THROUGH SUNDAY. COLD FRONT MOVING FROM THE NORTH REMAINS TO BE
SEEN IF IT WILL ACTUALLY MOVE SOUTH OF THE OUTER COASTAL WATERS
TUESDAY OR EARLY WEDNESDAY. AT THIS TIME...FORECAST WILL REFLECT
IT MOVING INTO THE COASTAL WATERS AND BECOMING STATIONARY...WHICH
WOULD INCREASE THE RISK OF STORMINESS IN THE MARINE AREAS NEXT
WEEK.

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  71  93  74  94 /  20  10  10  10
BTR  73  94  74  94 /  20  20  10  20
ASD  72  92  74  92 /  20  30  10  20
MSY  76  93  78  92 /  20  30  10  20
GPT  76  92  77  91 /  20  30  10  20
PQL  75  92  73  91 /  20  20  20  20

&&

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

$$







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