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

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711
FXUS64 KLIX 101311
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
811 AM CDT WED SEP 10 2014

...SOUNDING DISCUSSION...

A WARM NOSE EXISTS AROUND 500MB AND THERE IS A VERY SMALL
TEMPERATURE INVERSION AROUND 550MB ON THIS MORNING/S SOUNDING.
ALONG WITH A MORE STABLE ATMOSPHERE /LIFTED INDEX OF
-3.7/...OVERALL THUNDERSTORM COVERAGE SHOULD BE MORE LIMITED TODAY.
STORMS THAT DO FORM WILL MOVE SLOWLY WITH A STORM MOTION OF 3
KNOTS. WHILE DRIER AIR HAS ARRIVED ABOVE 600MB...THE ATMOSPHERE IS
STILL QUITE MOIST WITH A PRECIPITABLE WATER VALUE NEAR 2 INCHES.
WINDS WERE FROM THE SOUTHWEST OR SOUTH FROM THE SURFACE TO 12400
FEET...THEN SHIFTED AND BECAME FROM THE NORTHEAST FROM 22500 FEET
TO THE TROPOPAUSE. A MAXIMUM WIND SPEED OF 53 KNOTS WAS LOCATED AT
41500 FEET.

12Z BALLOON INFO: A SUCCESSFUL FLIGHT THIS MORNING THAT TERMINATED
35 MILES DOWNRANGE OVER THE SOUTHWEST PART OF LAKE PONTCHARTRAIN
AT A HEIGHT OF 21.1 MILES ABOVE THE GROUND.

ANSORGE

&&

.DECISION SUPPORT...


&&

.PREV DISCUSSION... /ISSUED 309 AM CDT WED SEP 10 2014/

SYNOPSIS...

STATIONARY FRONT FROM YESTERDAY NO LONGER DISCERNIBLE ON SURFACE
MAP. HIGH PRESSURE CENTERED TO THE EAST OF THE APPALACHIANS THIS
MORNING. LOW PRESSURE OVER IOWA HAS A COLD FRONT EXTENDING
SOUTHWEST TO THE TEXAS PANHANDLE. THERE IS AN EASTERLY WAVE OVER
THE EASTERN GULF OF MEXICO WHICH IS TRIGGERING ISOLATED SHOWERS
OVER OUR COASTAL WATERS. A FEW OF THE SHOWERS HAVE MOVED ON LAND
ALONG THE MISSISSIPPI AND LOUISIANA COASTS...BUT COVERAGE IS VERY
SMALL. AWAY FROM MARINE INFLUENCES...TEMPERATURES ARE GENERALLY IN
THE MIDDLE 70S.

SHORT TERM...

UPPER RIDGING FORECAST TO REMAIN CENTERED ALONG THE GULF COAST
THROUGH FRIDAY. THE EASTERLY WAVE IN THE EASTERN GULF IS EXPECTED
TO CONTINUE MOVING WESTWARD ACROSS THE GULF...REACHING THE TEXAS
COAST THURSDAY NIGHT. MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY
WITH THIS FEATURE IS EXPECTED TO REMAIN OVER THE COASTAL
WATERS...WITH ONLY ISOLATED CONVECTION OVER LAND AREAS TODAY. THE
COLD FRONT TO OUR NORTHWEST WILL MOVE SLOWLY TOWARD THE
AREA...LOSING ITS PUSH BY FRIDAY AS THE SURFACE AND UPPER LOWS
MOVE EAST THROUGH CANADA. THE FRONT LOOKS LIKE IT WILL BE NEAR OUR
NORTHERN BORDER BY FRIDAY EVENING. ONSHORE FLOW AHEAD OF THE FRONT
WILL MAKE SURE THERE IS SUFFICIENT MOISTURE FOR THE DEVELOPMENT OF
SCATTERED THUNDERSTORMS BY THURSDAY AFTERNOON AND AGAIN ON FRIDAY
AHEAD OF THE FRONT. WILL CARRY CHANCE POPS BOTH AFTERNOONS...VERY
LITTLE CHANGE FROM PREVIOUS FORECAST. TEMPERATURES WILL CONTINUE A
BIT ABOVE NORMAL THROUGH FRIDAY...WHERE EARLY DEVELOPMENT OF
CONVECTION DOES NOT CUT OFF HEATING. A BLENDED APPROACH CONTINUES
TO BE USED. 35

LONG TERM...

NOT MUCH CHANGE TO THE EXTENDED PACKAGE THIS MORNING AS MEDIUM
RANGE MODELS CONTINUE TO SHOW THE COLD FRONT BECOMING STATIONARY
OVER THE AREA FOR THE WEEKEND. THIS WILL BRING SCATTERED AFTERNOON
AND EARLY EVENING CONVECTION FOR SATURDAY THROUGH MONDAY. BY
MONDAY AFTERNOON OR TUESDAY...UPPER RIDGING MAY GET PUSHED
SOUTHWARD INTO THE GULF SOMEWHAT. THIS WILL ALLOW ANOTHER FRONT TO
TAKE A RUN AT MOVING THROUGH THE AREA AT MIDWEEK. FOR NOW WILL
NOTE A FEW DEGREES OF COOLING FOR TUESDAY AND WEDNESDAY WITH LOWER
POPS ON WEDNESDAY. HOWEVER...THE COOLING REFERRED TO WILL ONLY
LOWER TEMPERATURES TO NORMAL FOR MID SEPTEMBER. 35

AVIATION...

LIGHT FOG HAS BEGUN TO DEVELOP AT MCB AND HUM. VIS MAY DROP TO IFR
AT THOSE LOCATIONS. OTHERWISE...PATCHY LIGHT MAY TEMPORARILY DEVELOP
AT OTHER TERMINALS. EXPECT THESE CONDITIONS TO QUICKLY IMPROVE AFTER
SUNRISE. VFR CIGS AND VIS WILL PREVAIL TODAY WITH LOWER CONVECTION
COVERAGE. NOT PLANNING ON HAVING VCTS MENTIONED IN THE TAFS AS THE
PROBABILITY APPEARS TO BE TO LOW. IF A STORM DOES DEVELOP OVER A
TERMINAL...PERIODS OF MVFR TO IFR CONDITIONS WILL BE POSSIBLE ALONG
WITH WIND GUSTS TO 30 KTS.

MEFFER

MARINE...

STILL STATUS QUO WITHOUT MUCH CHANGE TO PREVIOUS COASTAL WATER
FORECAST. HIGH PRESSURE WILL PERSIST OVER THE NORTH GULF TODAY
THROUGH FRIDAY RESULTING IN LIGHT AND VARIABLE WINDS AS WELL AS SEAS
GENERALLY 1 FOOT OR LESS. THESE CONDITIONS ARE EXPECTED TO PERSIST
ACROSS THE COASTAL WATERS DURING THIS PERIOD. MODELS INDICATING THAT
A COLD FRONT WILL PUSH INTO THE COASTAL WATERS THIS WEEKEND. WINDS
WILL GRADUALLY BECOME MORE NORTHEAST WITH A BACKING TO MORE DUE EAST
WITH TIME. SPEEDS WILL BE IN THE 10 TO 15 KNOT RANGE.

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  91  73  92  72 /  20  10  30  20
BTR  93  74  93  73 /  20  10  30  20
ASD  90  75  91  73 /  20  10  30  20
MSY  91  77  90  77 /  20  10  30  20
GPT  90  77  90  75 /  20  10  30  20
PQL  90  75  91  72 /  20  10  30  20

&&

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

$$








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