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

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000
FXUS64 KLIX 050915
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
415 AM CDT THU MAY 5 2016

.SHORT TERM...

DEEP LAYER NORTHWEST FLOW AND STRONG NEGATIVE VORTICITY ADVECTION
WILL CONTINUE TO BRING CLEAR SKIES...LOW HUMIDITIES...AND SLIGHTLY
COOLER THAN NORMAL TEMPERATURES TO THE AREA THROUGH TOMORROW.
HEADING INTO SATURDAY AND SUNDAY...DEEP LAYER RIDGING WILL DEVELOP
ACROSS THE GULF SOUTH. STRONG SUBSIDENCE WILL RESULT IN
COMPRESSIONAL HEATING WHICH WILL ALLOW DAYTIME HIGHS TO RISE BACK
TO MORE NORMAL LEVELS IN THE MIDDLE 80S. WITH LOW HUMIDITIES STILL
IN PLACE...THE DIURNAL RANGE WILL BE FAIRLY LARGE. OVERNIGHT LOWS
WILL EASILY DIP INTO THE 50S AND LOWER 60S SATURDAY NIGHT.

.LONG TERM...

THE RIDGE AXIS WILL PUSH EAST OF THE AREA BY MONDAY...AND AN
APPROACHING UPPER LEVEL TROUGH OVER THE ROCKIES WILL BEGIN TO TAKE
ON A NEGATIVE TILT AND EJECT INTO THE PLAINS STATES. THE STRONGEST
FORCING ASSOCIATED WITH THIS SYSTEM WILL REMAIN WELL NORTH OF THE
FORECAST AREA. HOWEVER...WITH THE RIDGE TO THE EAST...INCREASED
ONSHORE FLOW WILL ALLOW FOR SOME MOISTURE ADVECTION TO TAKE PLACE
SUNDAY NIGHT INTO MONDAY. INSTABILITY WILL BE ON THE RISE...WITH
CAPE VALUES PEAKING OUT CLOSE TO 1000 J/KG MONDAY AFTERNOON. THIS
INSTABILITY COMBINED WITH AN INCREASE IN OVERALL FORCING ALOFT AS
THE TROUGH AXIS SLIDES THROUGH SHOULD BE ENOUGH TO ALLOW FOR
ISOLATED SHOWERS AND THUNDERSTORMS TO POP UP MONDAY AFTERNOON.
RAIN CHANCES WILL BE GREATEST OVER THE NORTHERN HALF OF THE
FORECAST AREA WHERE FORCING IS EXPECTED TO BE STRONGEST.

A LARGELY ZONAL FLOW REGIME WILL DEVELOP IN THE WAKE OF THE
PASSING TROUGH AXIS FOR TUESDAY AND WEDNESDAY. WEAK VORTICITY
MAXIMA RIDING ALONG THROUGH THIS FLOW WILL PROVIDE JUST ENOUGH
LIFT IN THE UPPER LEVELS TO SUPPORT ONGOING LARGELY DIURNAL
CONVECTION EACH DAY. THE AREA WILL ALSO SEE CONTINUED INCREASES IN
LOW LEVEL INSTABILITY AS TEMPERATURES CLIMB INTO THE MIDDLE TO
UPPER 80S AND DEWPOINTS RISE BACK INTO THE 60S DUE TO PERSISTENT
ONSHORE FLOW. SURFACE BASED CAPE VALUES WILL EASILY CLIMB TO
AROUND 1500 TO 2000 J/KG EACH AFTERNOON...AND EXPECT TO SEE
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP AS THE CONVECTIVE
TEMPERATURE IS REACHED. OVERALL...KEEP POPS IN THE 30 PERCENT
RANGE FOR BOTH TUESDAY AND WEDNESDAY.

&&

.AVIATION...

CLEAR SKIES AND EXCELLENT VSBYS WILL RESULT IN VFR CONDITIONS
PREVAILING THROUGH FRIDAY MORNING. A SECOND SURGE WILL YIELD A
NORTHEAST WIND DIRECTION FOR MOST TAF SITES THURSDAY EVENING AND
WIND SPEEDS OF 12 TO 19 KNOTS ARE EXPECTED KMSY AND KNEW AFTER 00Z
FRIDAY. 18

&&

.MARINE...

WINDS ARE NOT AS STRONG AS ORIGINALLY FORECAST...AND WILL INSERT
SMALL CRAFT EXERCISE CAUTION THIS MORNING THROUGH NOON TODAY.
ANOTHER SURGE OF COLD AIR WILL PUSH THROUGH THE COASTAL WATERS THIS
EVENING. 1000 TO 700MB THICKNESS LAYERS ARE EXPECTED TO DECREASE
AROUND 30M THIS EVENING AND OVERNIGHT. THIS COLD AIR ADVECTION OVER
WATER TEMPS IN THE MID 70S WILL CREATE A BITE INSTABILITY AND
BOUNDARY LAYER WINDS 20 TO 23 KNOTS WILL MIX DOWN TO THE SEA SURF
OVER THE COASTAL WATERS TONIGHT. WILL ISSUE A SMALL CRAFT ADVISORY
FOR OPEN AND PROTECTED WATERS FOR TONIGHT. MAIN UPPER LEVEL TROUGH
WILL LIFT NORTHEAST FRIDAY AND WINDS SHOULD DROP OFF EARLY FRIDAY
MORNING.

HIGH PRESSURE SHOULD THEN BECOME CENTERED OVER THE WATERS BY
SATURDAY...WITH LIGHT WINDS OF LESS THAN 10 KNOTS AND SEAS OF AROUND
1 FOOT EXPECTED. THE HIGH SHOULD PUSH EAST OF THE AREA EARLY NEXT
WEEK...AND SOUTHERLY FLOW SHOULD GRADUALLY INCREASE ON MONDAY. WINDS
MAY RISE BACK INTO EXERCISE CAUTION RANGE OF 15 TO 20 KNOTS OVER THE
WESTERN WATERS BY MONDAY AFTERNOON...AND SEAS COULD CLIMB TO AROUND
5 FEET. 18

&&

.DECISION SUPPORT...

DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.

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 RISK SVR AND/OR DIRECT
         TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  76  49  78  50 /   0   0   0   0
BTR  79  52  80  53 /   0   0   0   0
ASD  78  49  79  51 /   0   0   0   0
MSY  79  58  78  59 /   0   0   0   0
GPT  79  51  79  54 /   0   0   0   0
PQL  78  49  79  49 /   0   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 AM CDT FRIDAY
     FOR GMZ530-532-534-536-538-550-552-555-557-570-572-575-577.

MS...NONE.
GM...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 AM CDT FRIDAY
     FOR GMZ532-534-536-538-550-552-555-557-570-572-575-577.

&&

$$

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