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

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945
FXUS64 KLIX 211520 AAA
AFDLIX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1020 AM CDT MON APR 21 2014

.UPDATE...
DID CLEAN UP CURRENT TEMP/DEWPOINT TRENDS IN GRID IN THE SH0RT-
TERM BUT NOT UPDATING ANY ACTUAL PUBLIC PRODUCTS...JUST NDFD
DATABASE VIEWING AT THIS TIME. OTHERWISE NO CHANGES.

&&

.AVIATION...
18Z TAF ISSUANCES WILL BE DEALING WITH MARINE LAYER CLOUD DECK
ROLLING OFF THE GULF AND IMPACTING KGPT/KPQL/KNEW/KASD AND
ADVANCING INLAND OVER TIME. THIS DECK WILL PRETTY MUCH STAY AT
MVFR LEVELS BUT MAY BOUNCE BETWEEN SCT-BKN THROUGHOUT THE DAY.
DECK TO LOWER TO LOWER END MVFR ALL TERMINALS OVERNIGHT WITH
POSSIBLY SOME IFR VSBYS IN RADIATIONAL/ADVECTIVE FOG MAINLY AFTER
06Z. 24/RR

&&

.SOUNDING DISCUSSION...
NO PROBLEMS WITH MORNING FLIGHT. SURFACE BASED SHALLOW INVERSION
OF 8F THROUGH 1007MB/400 FT...THEN RELATIVELY DRY LAYER TO BASE OF
SUBSIDENCE INVERSION AT 873MB...WARM TO ISOTHERMAL LAYER 10-12C TO
700 MB...ADIABATIC LAPSE RATE TO 510 MB...THEN PSEUDO TO
TROPOPAUSE AT 184MB. MODERATELY MOIST FROM SURFACE INVERSION TO
BASE OF SUBSIDENCE INVERSION THEN VERY DRY BETWEEN 800-650
MB...SOME LIMITED MOISTURE WITH DEPRESSIONS BETWEEN 8-10C TO 510
MB...THEN DRY ALOFT. WINDS SE-E 0-10 KT SURFACE TO
2300FT...VARBIABLE LESS THAN 15KT TO 7400FT...THEN W 5-75KT ABOVE.
PEAK WIND 270/76KT AT 38.3KFT. PRECIPITABLE WATER INCREASED
SLIGHTLY TO 0.92 INCHES SINCE PREVIOUS FLIGHT. LIFTED INDEX 2.5.

&&

.DECISION SUPPORT...
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


&&

.PREV DISCUSSION... /ISSUED 427 AM CDT MON APR 21 2014/

SYNOPSIS...
LATEST SURFACE ANALYSIS SHOWED A RIDGE AXIS FROM THE MID ATLANTIC
STATES TO NORTH CENTRAL GULF OF MEXICO. SURFACE DEWPOINT READINGS
HAVE REBOUNDED OVER THE WEEKEND WITH VALUES FROM 58 TO 63 ACROSS
THE WEST ZONES DOWN TO 52 TO 57F ACROSS THE EAST ZONES. UPPER AIR
ANALYSIS AND IR SATELLITE IMAGERY SHOWED A SHORT WAVE OVER THE
CENTRAL PLAINS. ISOTACH ANALYSIS AT 250MB SHOWED A JET MAX NEAR 75
KNOTS ON THE FRONT SIDE OF THE WAVE AXIS FROM CENTRAL TEXAS TO
CENTRAL ARKANSAS AND SUB-TROPICAL JET STREAM FROM JUST SOUTH OF
BAJA CALIFORNIA TO SOUTH TEXAS TO FLORIDA PENINSULA. THIS
POSITIONING OF JETS CREATES A DIVERGENCE AREA ALOFT JUST WEST OF
ARKLATEX REGION. PRECIPITABLE WATER VALUES AT 00Z ON A PLANER VIEW
REVEALED THE WEDGE OF DRY VALUES FROM OHIO VALLEY TO CENTRAL GULF
WITH VALUES FROM 0.5 TO 0.85 INCH AND A SWATH OF MOISTURE 1 TO 1.4
INCHES FROM WEST GULF TO CENTRAL TEXAS COAST TO CENTRAL OKLAHOMA
TO WESTERN MISSOURI...MAINLY AHEAD OF THE SHORT WAVE.

SHORT TERM...
FOR MONDAY AND TUESDAY...THE APPROACHING SHORT WAVE WILL BE THE
MAIN WEATHER MAKER FOR THE NEXT 48 HOURS. WITH DEWPOINT TEMPERATURES
INCREASING TO THE 60S TODAY AND TONIGHT...AMBIENT TEMPS AND
DEWPOINTS WILL MEET RATHER QUICKLY ACROSS THE NORTH HALF OF ZONES
THIS EVENING. CLOUD COVER IS EXPECTED TONIGHT AND COULD HAMPER FOG
DEVELOPMENT FROM BECOMING WIDESPREAD FOR LONG DURATION TONIGHT BUT
CANT RULE A FEW AREAS EXPERIENCING PATCHY DENSE FOG AT TIMES EARLY
TUESDAY MORNING. WILL INSERT PATCHY FOG FOR NOW ACROSS THE NORTH ZONES.
SHORT WAVE OVER THE CENTRAL PLAINS WILL MOVE EAST TO SOUTHEAST
TODAY THROUGH TUESDAY AND REMAIN POSITIVELY TILTED. THIS WILL
PLACE THE SLIGHT DIVERGENCE AREA OVER THE NORTH HALF ZONES ON
TUESDAY BUT SLIGHT TO NIL VEERING WINDS WILL BE PRESENT FROM SURF
TO 700MB BEFORE THE WAVE. MOISTURE AXIS WILL MOVE EAST ALSO WITH
1.4 INCHES OVER THE NORTH ZONES TUESDAY MORNING ...THEN SOUTH
ZONES TUESDAY AFTERNOON. SOME SURF BASE AND MID LAYER INSTABILITY
WILL BE PRESENT WITH CAPE VALUES INCREASING UP TO 1500J/KG.
ERGO...CONVECTION WILL BE PRESENT BUT WAVE WILL BECOME STRETCHED
AND WEAKEN AS IT MOVES EAST TODAY AND TUESDAY AND SEVERE STORMS
ARE NOT ANTICIPATED ON TUESDAY. THE ASSOCIATED FRONT WILL PUSH
INTO THE FORECAST AREA LATE TUESDAY AFTERNOON AND APPROACH/CLEAR
THE LAND AREA BY 12Z WED.

LONG TERM...
WEDNESDAY THROUGH THE WEEKEND...THE FRONTAL BOUNDARY WILL
WEDNESDAY AFTERNOON/NIGHT AND HIGH PRESSURE WILL SETTLE OVER THE
EAST GULF CREATING A WEAK SOUTH FLOW OVER THE AREA BY WEDNESDAY
NIGHT. ANOTHER STORM SYSTEM OVER THE NORTH PLAINS AND SURFACE
FRONT OVER THE PLAINS WILL QUICKLY YIELD A SOUTH FLOW FROM THE
CENTRAL GULF TO THE MID MISSISSIPPI VALLEY. THIS SYSTEM WILL NOT
APPROACH THE AREA BUT THE NEXT SYSTEM...FARTHER SOUTH TRACK...WILL
TAP DEEPER MOISTURE ACROSS THE CENTRAL GULF AND CREATE A SLIGHT RAIN
CHANCE OVER THE WEEKEND.

AVIATION...
SKIES HAVE BEEN MOSTLY CLEAR UNTIL THE LAST FEW HOURS WHEN A PATCH
OF LIFR CLOUDS DEVELOPED FROM NEAR BTR TO MCB. OTHERWISE...FEW
IMPACTS TO TERMINALS AT THIS TIME WITH LIGHT TO NEAR CALM WINDS.
THIS MAY LEAD TO SOME PATCHY FOG AROUND SUNRISE...SO HAVE INCLUDED
4SM BR AT A FEW TAF AIRPORTS FOR A FEW HOURS DURING 10-14Z. VFR
CONDITIONS ARE THEN EXPECTED TO PREVAIL FROM MID MORNING THROUGH THE
EVENING ON MONDAY AS A MID LEVEL CLOUD DECK DEVELOPS.

MEFFER

MARINE...
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AS THE RIDGE TRACKS
WEST TOWARDS THE WESTERN GULF OF MEXICO. WINDS WILL SHIFT OUT OF THE
NORTH TUESDAY NIGHT AS A WEAK COLD FRONT PUSHES THROUGH. WINDS
SHOULD REMAIN BELOW 15 KNOTS AROUND THIS FRONTAL BOUNDARY. UP UNTIL
THE COLD FRONT EXPECT PRETTY BENIGN CONDITIONS ON THE WATERS.
FRONTAL BOUNDARY WILL DISSIPATE ON WEDNESDAY AND SOUTHERLY FLOW WILL
DEVELOP OVER THE COASTAL WATERS WEDNESDAY NIGHT AS THE SURFACE HIGH
SHIFTS BACK EAST. ONSHORE FLOW WILL CONTINUE THEN THROUGH THE
WEEKEND.

MEFFER

DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
             MONITORING RIVER FLOODING
             SMALL CRAFT ADVISORY


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  80  58  79  58 /  10  10  40  10
BTR  83  60  84  58 /  10  10  30  10
ASD  78  59  79  59 /  10  10  30  10
MSY  78  62  79  64 /  10  10  30  10
GPT  74  62  77  61 /  10  10  30  10
PQL  74  56  77  60 /  10  10  30  10

&&

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

$$








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