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

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693
FXUS64 KLIX 152116
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
416 PM CDT TUE JUL 15 2014

.SYNOPSIS...
UPPER AIR ANALYSIS SHOWED A CYCLONIC CIRCULATION OVER THE GREAT
LAKES REGION WITH A TROUGH AXIS EXTENDING SOUTHWEST TO LOWER
MISSISSIPPI VALLEY. IN ADDITION...IR SATELLITE IMAGERY SHOWED
MOISTURE ALONG THE EASTERN SEABOARD TO GEORGIA TO UPPER TEXAS
COAST. THIS MORNING SOUNDING REVEALED A CAPE VALUE AROUND
4500J/KG...HELICITY BELOW 25M/S...WET BULB ZERO TEMPERATURE HEIGHT
DOWN TO 13.8 KFT AND SURFACE/LIGHT LOW LEVEL FLOW WAS WESTERLY.
PEA SIZED HAIL WAS REPORTED IN MANDEVILLE AROUND 3PM THIS
AFTERNOON...SO SOME MELTING STONES ARE MAKING IT TO THE
GROUND...BUT NOT SEVERE. PW VALUE WAS 2.1 INCHES. THE MAIN THREAT WILL
HEAVY RAINFALL AT TIMES AND GUSTY WINDS THROUGH THIS EVENING. THE
SURFACE MAPS SHOWED THE FRONTAL BOUNDARY EXTENDING FROM NORTH
GEORGIA TO SOUTHWEST MISSISSIPPI TO SOUTHEAST TEXAS.

&&

.DISCUSSION...

THROUGH TONIGHT...UPPER LEVEL TROUGH WILL CONTINUE LIFT EAST AND
AS THE MAIN TROUGH MOVES THROUGH THE MISSISSIPPI VALLEY.
ASSOCIATED FRONT WILL ALSO PRESS SOUTHWARD PRODUCING SOME LIFT
ALONG THE GULF COAST. WEST FLOW FROM THE SURFACE TO 400MB WILL
ALLOW CONVECTION TO TRAIN ACROSS PARTS OF THE FORECAST AREA AT
TIMES THIS AFTERNOON AND THIS EVENING. MOISTURE WILL QUICKLY BE
DISPLACED SOUTHEAST AND RAIN WILL LIKELY DIMINISH AROUND MIDNIGHT
AND NO RAIN WEDNESDAY MORNING. FRONT WILL PUSH INTO THE FORECAST
AREA OVERNIGHT WITH THE WIND SHIFT FOR MOST AREAS LATE THIS
EVENING AND OVERNIGHT...STALL OVER THE COASTAL WATERS. TEMPS ARE
EXPECTED TO RESPOND DOWN...ESPECIALLY AT NIGHT WITH THE DRIER
AIR IN PLACE...FOR WEDNESDAY AND THURSDAY MORNINGS ACROSS THE NORTH
HALF.

WITH GREATEST PUSH OVER THE LOWER MISSISSIPPI VALLEY AND NORTHEAST
GULF OF MEXICO...CLEARING WILL BE SHORT LIVED AS MOISTURE WILL
REMAIN OVER THE CENTRAL PLAINS AND TEXAS. A SECONDARY WAVE WILL
LIKELY TAP THIS MOISTURE AND MOVE ACROSS THE LOWER MISSISSIPPI
VALLEY AND MID SOUTH AREA EARLY FRIDAY MORNING THROUGH FRIDAY
NIGHT. THE PLUME MOISTURE ASSOCIATED WITH THIS WAVE MOVE OVER THE
FORECAST FRIDAY AND LINGER THROUGH THE WEEKEND. WILL MAINTAIN RAIN
CHANCES TO ABV NORMS DURING THIS TIME.

&&

.AVIATION...

MESOSCALE MODELING INDICATES THAT CONVECTIVE THREAT BEGINS
DECREASING INCREASING AROUND 03Z WED NORTHERN SECTIONS OF THE
AREA AND DIMINISH SOUTHWARD OVERNIGHT. WILL CONTINUE CURRENT
FORECAST TREND OF TEMPO TSRA DURING THE AFTERNOON/THIS EVENING.
LOW LEVEL NORTH FLOW WILL SCOUR OUT MOISTURE AND MVF CONDITION
WILL BE PRESENT AT ALL TAF SITES 06Z WEDNESDAY.

&&

.MARINE...

A TIGHTENING PRESSURE GRADIENT IN RESPONSE TO AN APPROACHING
FRONT WILL ALLOW FOR WEST WINDS AHEAD OF THE FRONT TO INCREASE TO
AROUND 10 TO 15 KNOTS TONIGHT. THIS INCREASE IN WINDS WILL PUSH
SEAS FROM AROUND 1 FOOT TO CLOSER TO 2-3 FEET IN SOME AREAS. THE
FRONT IS EXPECTED TO PUSH INTO THE AREA AND POSSIBLY EVEN THE
SOUNDS BUT STALL BEFORE MAKING IT INTO THE COASTAL WATERS. WINDS
WILL REACH EXERCISE CAUTION LEVELS TONIGHT AND EARLY WEDNESDAY
WELL OFFSHORE BUT DROP OFF MID MORNING WEDNESDAY. HIS AFTERNOON
THROUGH TOMORROW MORNING BUT SHOULD REMAIN JUST BELOW 15 KNOTS.

&&

.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
             MONITORING CONVECTIVE TRENDS THIS AFTERNOON.

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  65  86  61  91 /  30  10  10  10
BTR  69  89  65  92 /  40  10  10  10
ASD  69  89  63  91 /  40  10  10  10
MSY  74  89  70  90 /  60  10  10  10
GPT  71  90  65  89 /  60  10  10  10
PQL  70  90  62  90 /  60  10  10  10

&&

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

$$







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