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619
FXUS64 KLIX 120445
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1145 PM CDT SAT MAY 11 2013

.AVIATION...

ALL SIGNIFICANT PRECIPITATION HAS MOVED AWAY FROM LOCAL TERMINALS.
ON THE LARGER SCALE...MAINLY A CIRRUS DECK AFFECTING THE TERMINALS
NEAR THE COAST AND THE NEW ORLEANS TERMINALS. A FEW CLOUDS LINGER
BETWEEN FL020 AND FL040. THERE ARE A COUPLE TERMINALS REPORTING
FOG...KHDC WITH LIGHT FOG...AND KHUM WITH DENSE FOG...VLIFR
VISIBILITIES AND IFR CEILINGS. EXPECT LITTLE CHANGE AT KHUM UNTIL
DRIER AIR WORKS IN TOWARD SUNRISE. KHDC WILL PROBABLY SEE MVFR
VISIBILITIES BUT COULD BE RATHER CHANGEABLE. ONCE THE SLIGHTLY
COOLER AND DRIER AIR WORKS INTO THE AREA DURING THE MID MORNING
HOURS...ANTICIPATE VFR CONDITIONS FOR THE REMAINDER OF THE
FORECAST PERIOD WITH VARIABLE AMOUNTS OF CIRRUS CLOUDS. 35

&&

.PREV DISCUSSION... /ISSUED 342 PM CDT SAT MAY 11 2013/

SHORT TERM...

A COLD FRONT CURRENTLY MOVING THROUGH WESTERN LOUISIANA AND
CENTRAL MISSISSIPPI WILL BEGIN TO MOVE INTO THE FORECAST AREA LATER
THIS EVENING. THE FRONT IS BEING DRIVEN SOUTH AND EAST BY A STRONG
LONG WAVE TROUGH RAPIDLY DEEPENING OVER THE PLAINS AND GREAT LAKES
REGION OF THE COUNTRY. SOME SHOWER ACTIVITY HAS DEVELOPED IN
ADVANCE OF THE FRONT THIS AFTERNOON...IN A REGION OF INCREASED
DIFFERENTIAL HEATING AND WEAK CONVERGENCE. THESE SHOWERS WILL
CONTINUE INTO THE EARLY EVENING HOURS...AND HAVE KEPT IN A CHANCE
OF PRECIP ALONG THE COAST. THE FRONT WILL CONTINUE TO SOUTH AND
EAST...FINALLY PUSHING OFFSHORE BY THE EARLY MORNING HOURS
TOMORROW. HOWEVER...LINGERING SHOWER ACTIVITY WILL CONTINUE OVER
THE OFFSHORE COASTAL WATERS THROUGH THE DAY TOMORROW. BEHIND THE
FRONT...STRONG DRY AIR ADVECTION AND SUBSIDENCE WILL RESULT IN
MOSTLY CLEAR SKIES AND MUCH LOWER HUMIDITIES ACROSS THE REGION.
WEAK COLD AIR ADVECTION WILL ALSO BE TAKING HOLD...WHICH WILL KEEP
TEMPERATURES A GOOD 5 DEGREES BELOW NORMAL.

THE COLDER AND DRIER AIRMASS WILL ALSO ALLOW FOR A LARGER THAN
NORMAL DIURNAL RANGE FOR BOTH MONDAY AND TUESDAY. OVERNIGHT LOWS
WILL BE A GOOD 10 TO 15 DEGREES BELOW NORMAL EACH NIGHT...AND
DAYTIME HIGHS WILL GRADUALLY RECOVER TO MORE NORMAL LEVELS BY
TUESDAY. OVERALL...A VERY BENIGN WEATHER REGIME WILL TAKE HOLD OF
THE AREA AS DEEP LAYER NORTHWEST FLOW ON THE BACKSIDE OF THE UPPER
LEVEL TROUGH DOMINATES THE REGION.

LONG TERM...

THE TROUGH WILL PULL TO THE EAST ON WEDNESDAY...ALLOWING AN UPPER
LEVEL RIDGE AXIS TO MOVE OVER THE AREA. THIS STRONG RIDGING
ALOFT...COMBINED WITH LOW LEVEL FLOW OFF THE GULF OF MEXICO
REDEVELOPING WILL RESULT IN A MORE TYPICAL MAY WEATHER REGIME
TAKING HOLD BY WEDNESDAY. HIGHS WILL ONCE AGAIN RISE INTO THE
MIDDLE 80S AND OVERNIGHT LOWS WILL ONLY COOL INTO THE 60S. HEADING
INTO THURSDAY AND FRIDAY...A WEAK SHORT WAVE TROUGH WILL SLIDE
THROUGH THE LOWER MISSISSIPPI VALLEY. THIS WEAK SYSTEM WILL
INCREASE LAPSE RATES AND OVERALL INSTABILITY. THIS HIGHER OVERALL
INSTABILITY COMBINED WITH INCREASED MOISTURE ADVECTING INTO THE
AREA WILL ALLOW FOR SOME ISOLATED DIURNAL CONVECTION TO DEVELOP
BOTH THURSDAY AND FRIDAY. THERE WILL BE A LACK OF ANY SYNOPTIC
SCALE LOW LEVEL FEATURES TO FOCUS CONVECTION ON...SO THE
CONVECTION WILL MOST LIKELY FORM ON ANY MESOSCALE BOUNDARIES IN
THE REGION. OVERALL...A MORE SUMMER-LIKE PATTERN WILL BEGIN TO
TAKE HOLD BY THE END OF THE WEEK.

AVIATION...

MVFR CEILINGS WILL BEGIN TO CLEAR BETWEEN 00Z AND 03Z TONIGHT...AS
A COLD FRONT MOVES THROUGH AND A MUCH DRIER AIRMASS ADVECTS IN.
EXPECT TO SEE SKIES TURN CLEAR AT ALL TERMINALS BY 06Z...WITH VFR
CONDITIONS BEING THE RULE THROUGH THE REMAINDER OF THE FORECAST
PERIOD.

MARINE...

WEAK COLD AIR ADVECTION IN THE WAKE OF A PASSING COLD FRONT WILL
RESULT IN A PERIOD OF EXERCISE CAUTION CONDITIONS OVER THE GULF
COASTAL WATERS BEGINNING TOMORROW AND PERSISTING THROUGH MONDAY
MORNING. NORTH TO NORTHEAST WINDS OF 15 TO 20 KNOTS AND SEAS OF 3
TO 5 FEET CAN BE EXPECTED. WINDS WILL BEGIN TO WANE BY MONDAY
AFTERNOON AND WILL GRADUALLY SHIFT TO A MORE EAST AND SOUTHEAST
DIRECTION ON TUESDAY. SOUTHEASTERLY FLOW OF AROUND 10 KNOTS AND
SEAS OF 2 TO 3 FEET CAN BE EXPECTED FROM TUESDAY THROUGH THURSDAY.
32

DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT.
             MONITORING RIVER FLOODING.

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  56  76  47  78 /  10  10  10  10
BTR  59  80  49  80 /  10  10  10  10
ASD  59  79  49  77 /  20  10  10  10
MSY  63  78  56  78 /  20  10  10  10
GPT  60  79  49  77 /  20  10  10  10
PQL  59  79  48  77 /  20  10  10  10

&&

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

$$