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

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544
FXUS64 KLIX 290952
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
452 AM CDT SUN MAR 29 2015

.SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...

A WARMING TREND WILL BRING TEMPERATURES BACK ABOVE THE SEASONAL
NORMALS THE NEXT FEW DAYS AS THE CENTER OF SURFACE HIGH PRESSURE
TO THE EAST BRINGS SOUTHERLY WINDS...AND THE MID/UPPER LEVEL WINDS
SHIFT FROM NORTHWEST TO MORE WESTERLY. SATELLITE IMAGERY WITH LOW
CLOUD ENHANCEMENT SHOWS AREAS OF LOW CLOUDS INCREASING OVER
PORTIONS OF THE AREA...AND SOME LIGHT FOG HAD DEVELOPED ACROSS
PORTIONS OF SOUTHEAST LOUISIANA FROM GONZALES TO HOUMA. SOME
PATCHY MAINLY LIGHT FOG WILL LIKELY CONTINUE OVER THE SOUTHWEST
PORTION OF THE FORECAST AREA EARLY THIS MORNING...OTHERWISE IT
WILL BE A PARTLY CLOUDY DAY. PRECIPITABLE WATER VALUES ARE
EXPECTED TO RISE TO AROUND ONE INCH TODAY HOWEVER...THE LOW LEVEL
MOISTURE AROUND 850 MB WILL HAVE A FAIRLY STRONG CAPPING INVERSION
WITH DRY AIR THAT WILL SUPPRESS MOST CONVECTIVE UPDRAFTS. THE GFS
MAV MOS GUIDANCE AND THE HRRR INDICATES THE POTENTIAL FOR SOME
ISOLATED LIGHT SHOWERS TODAY...HOWEVER HAVE OPTED TO LEAVE THEM
OUT OF THE FORECAST CONSIDERING HOW DRY THE AIRMASS REMAINS AT
THIS TIME.

THE LIGHT SOUTHERLY WINDS AND MOSTLY CLEAR TO PARTLY CLOUDY SKIES
WILL ADVECT HIGHER DEWPOINT TEMPERATURES...AND THIS CONTINUES TO
LOOK FAVORABLE FOR AREAS OF FOG TO DEVELOP LATE TONIGHT THROUGH
EARLY MONDAY MORNING. WILL ALSO BE KEEPING NO MENTION OF RAIN IN
THE FORECAST. THE LOWS TONIGHT ARE EXPECTED TO BE AROUND 10
DEGREES WARMER THAN THIS MORNING.

A POTENT SHORTWAVE TROUGH NOW OVER THE NORTHERN PLAINS WILL BE
MOVING SOUTHEAST AND REACHING THE EASTERN SEABOARD OF THE U.S. ON
MONDAY. THE WEAKER SOUTHERN PORTION OF THIS SYSTEM WILL HAVE A
DISSIPATING COLD FRONT AND BAND OF SHOWERS AND SOME THUNDERSTORMS
PUSHING INTO NORTHERN LOUISIANA AND NORTHERN AND CENTRAL PORTIONS
OF MISSISSIPPI ON MONDAY. FAR REMOVED FROM THE EFFECTS OF THE WEAK
FRONT...THE MODELS CONTINUE TO INDICATE SHALLOW LOW LEVEL MOISTURE
YIELDING PRECIPITABLE WATER VALUES JUST ABOVE ONE INCH WITH A MUCH
WEAKER CAPPING INVERSION AND MODERATE INSTABILITY. ISOLATED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING
AND AFTERNOON. THE FRONTAL BOUNDARY TO OUR NORTH WILL DISSIPATE BY
TUESDAY...HOWEVER THE AIRMASS OVER THE FORECAST AREA WILL REMAIN
SUPPORTIVE OF SOME ISOLATED SHOWERS AND A FEW THUNDERSTORMS WITH
DAYTIME HEATING PRIMARILY DURING THE LATE MORNING AND AFTERNOON
HOURS.

.LONG TERM /WEDNESDAY THROUGH SATURDAY NIGHT/...

THE MAIN SYSTEM OF CONCERN WILL BE A DEVELOPING SHORTWAVE TROUGH
OVER TEXAS AND ADJACENT MEXICO ON TUESDAY AND TUESDAY NIGHT THAT
SHOULD MOVE EAST ACROSS THE CENTRAL GULF COAST REGION WEDNESDAY
AFTERNOON AND WEDNESDAY NIGHT. THE MODELS...PRIMARILY THE
OPERATIONAL RUNS OF THE 00Z GFS AND ECMWF...ARE IN PRETTY GOOD
AGREEMENT ON THE TIMING OF THIS FEATURE WITH MAIN DIFFERENCE BEING
THE AMOUNT OF QPF ON WEDNESDAY NIGHT AND THURSDAY MORNING. THE
ECMWF IS QUITE A BIT WETTER AS HAS BEEN THE TREND THE LAST FEW
DAYS. AM CONTINUING TO BLEND THE MODELS WHICH PRODUCES POPS NEAR
TO SLIGHTLY HIGHER THAN THE HIGH MEMBER OF THE GFS ENSEMBLE MOS
GUIDANCE. INSTABILITY WILL REMAIN SUFFICIENT FOR MENTION OF
THUNDERSTORMS...HOWEVER THE SHEAR PROFILES AND FORCING DO APPEAR
FAVORABLE FOR ORGANIZED SEVERE THUNDERSTORMS.

THE MODELS KEEP SOME RAIN AROUND IN THE WAKE OF THE SHORTWAVE
TROUGH THROUGH THURSDAY AFTERNOON...EVEN WITHOUT ANY COLD FRONT
MOVING INTO THE REGION. THIS IS PRIMARILY DUE TO LINGERING
MOISTURE AND INSTABILITY WITH ABOVE NORMAL TEMPERATURES.

THE WESTERLIES AND UPPER JETSTREAM WILL BE SAGGING SOUTH INTO THE
UPPER PORTIONS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY
AS A SERIES OF SHORTWAVE TROUGH/DISTURBANCES MOVE THROUGH. THIS IS
EXPECTED TO DRIVE A PACIFIC COLD FRONT THROUGH THE FORECAST AREA
FRIDAY NIGHT AND EARLY SATURDAY. THE FORCING WILL NOT BE THAT
STRONG AND MOISTURE CONTENT NOT THAT HIGH...SO MOSTLY LIGHT QPF
AMOUNTS FROM ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS
ARE ANTICIPATED FRIDAY THROUGH SATURDAY MORNING WITH THE HIGHEST
RAIN CHANCE LOOKING TO BE ON FRIDAY NIGHT. TEMPERATURES ARE
EXPECTED TO LOWER TO NEAR TO SLIGHTLY BELOW NORMAL FRIDAY NIGHT
INTO NEXT WEEKEND.

22/TD
&&

.AVIATION...

HAVE BEEN SEEING SOME CLOUD COVER DEVELOP OVER SOUTHERN MISSISSIPPI
ON THE NOSE OF THE WARM AIR RETURN. THIS HAS BROUGHT OCCASIONAL MVFR
CIGS TO KMCB AROUND FL025-030...AND THOSE HAVE NOW LOWERED TO NEAR
FL015.

SINCE 08Z...HAVE ALSO BEEN SEEING CLOUDS DEVELOP NEAR LAKE
PONTCHARTRAIN...BUT THESE CEILINGS LOOK LIKE THEY MAY REMAIN ABOVE
FL030. EXPECT CEILINGS THAT ARE IN PLACE AROUND SUNRISE WILL SCATTER
OUT BY LATE MORNING. CANNOT RULE OUT A LITTLE FOG TOWARD MONDAY
MORNING...WILL CONTINUE TO MONITOR POTENTIAL. 35

&&

.MARINE...

NO REAL MARINE ISSUES TO SPEAK OF. ONSHORE WINDS MAY APPROACH 15
KNOTS TODAY...BUT DO NOT EXPECT SIGNIFICANT PERIODS OF WINDS GREATER
THAN 15 KNOTS...SO WILL NOT INCLUDE HEADLINE. SOUTHERLY FLOW ON TAP
FOR MUCH OF THE WORK WEEK WITH NO STRONG WEATHER SYSTEMS MOVING
THROUGH THE COASTAL WATERS. 35

&&

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

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  76  59  80  58 /   0  10  20  10
BTR  79  60  83  61 /  10  10  20  10
ASD  74  58  81  59 /  10  10  20  10
MSY  77  64  81  63 /  10   0  20  10
GPT  71  60  78  60 /  10  10  20  10
PQL  69  57  80  58 /  10  10  20  10

&&

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

$$



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