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

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724
FXUS64 KLIX 180314 AAA
AFDLIX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1014 PM CDT THU JUL 17 2014

.UPDATE...
WILL BE SENDING AN UPDATED ZONE PACKAGE TO REFLECT ADJUSTMENTS
UPWARD ON RAIN CHANCES FOR TONIGHT MAINLY IN THE WESTERN PORTIONS
OF THE FORECAST AREA. NO OTHER CHANGES AT THIS TIME.

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED TO SLOWLY ERODE TO MVFR CIGS AND VSBY
AS RAINFALL BECOMES MORE PRONOUNCED AND BASES LOWER FROM
ISENTROPIC LIFT PROCESSES DURING THE DAY FRIDAY. AT SOME
POINT...SHRA/TSRA WILL LIKELY BECOME PREDOMINANT CONDITION BUT
DIFFICULT TO INDICATE ONSET.

&&

.MARINE...
UPDATED POPS FOR THE WESTERN COASTAL WATERS TO ACCOUNT FOR ONGOING
AND INCREASING THUNDERSTORMS. THE TRIGGER POINT BELOW ATCHAFALAYA
BAY MAY BE THERE MUCH OF THE NIGHT WITH LITTLE TO NO TRANSLATION
EASTWARD UNTIL DAYBREAK.

&&

.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
             MONITORING HEAVY RAIN POTENTIAL.

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 329 PM CDT THU JUL 17 2014/

SYNOPSIS...
LATEST SURFACE ANALYSIS SHOWED THE FRONTAL BOUNDARY STRADDLING THE
CENTRAL GULF COAST TO WEST TEXAS. IN ADDITION...A LARGE SURFACE
HIGH WAS LOCATED OVER THE OHIO VALLEY AND A LIGHT AND VARIABLE
FLOW WAS NOTED OVER MID SOUTH...MISSISSIPPI AND LOUISIANA. SURFACE
DEWPOINTS WERE IN THE LOWER 60S. PRECIPITABLE WATER VALUES ON A
PLANER VIEW AT 12Z SHOWED A SWATH OF MOISTURE FROM NORTHWEST GULF TO
SOUTHERN OKLAHOMA WITH 1.9 INCHES AND 1.2 INCHES OVER SOUTHEAST
LOUISIANA...STABLE DRY AIR RETREATING EAST. UPPER AIR ANALYSIS
SHOWED THE POSITIVELY TILTED SHORT WAVE OVER KANSAS. ISOTACH
ANALYSIS SHOWED SOUTHWEST JET MAX OF 65 KNOTS AHEAD OF THE SHORT
WAVE. 18

DISCUSSION...
THE OLD BOUNDARY WILL BEGIN TO MOVE BACK NORTH THIS AFTERNOON AND
TONIGHT. THE SHORT WAVE TROUGH IS EXPECTED MOVE ACROSS THE MID
SOUTH AND MID MISSISSIPPI VALLEY LATE TONIGHT AND FRIDAY. MOISTURE
WILL QUICKLY RETURN AND DEEPEN ACROSS THE AREA TONIGHT AND
FRIDAY...WITH PRECIPITABLE WATER VALUES APPROACHING OR EXCEEDING 2
INCHES.

SOME OF THE STORMS FRIDAY AND FRIDAY NIGHT COULD BE ON THE
STRONGER SIDE WITH AN ISOLATED SEVERE STORM NOT OUT OF THE
QUESTION AS THE SHORT WAVE TROUGH INTERACTS WITH THE UNSTABLE AND
VERY MOIST AIRMASS OVER THE REGION WITH A FRONTAL BOUNDARY IN THE
VICINITY. 0-3KM HELICITY VALUES UP TO 200M/S ACROSS SOUTHWEST AND
SOUTH CENTRAL MISSISSIPPI AND EAST CENTRAL LOUISIANA FRIDAY.
HOWEVER...THE WIND FIELD WILL NOT BE PARTICULARLY STRONG WITH MID LEVEL
SOUTHWEST WINDS IN THE 25 TO 30 KNOT RANGE AND SURFACE TO 5000
FEET WITH SOUTH TO SOUTHWEST WINDS 20 KNOTS OR LESS.

WITH MOIST AIR MASS IN PLACE...LAPSE RATES ARE NOT EXPECTED TO BE
STEEP. THE SEVERE THREAT WILL LIKELY BE ISOLATED IN NATURE WITH
THE MAIN THREAT BEING DAMAGING WIND GUSTS. THE MAIN THREAT WILL BE
HEAVY RAIN WITH POSSIBLY 2 TO 4 INCHES FROM FRIDAY THROUGH SUNDAY.
RAINFALL TOTALS SINCE JULY 3RD REVEALED AMOUNTS 2 TO 5 INCHES
ACROSS THE CONCERNED AREA...NORTH HALF OF FORECAST AREA. DO EXPECT
ISOLATED NUISANCE FLOODING BUT WIDESPREAD FLOODING IS NOT EXPECTED AT
THIS TIME. CATEGORICAL RAIN CHANCE APPEAR TO BE IN ORDER FOR
FRIDAY AND FRIDAY EVENING AND LIKELY POPS FOR SATURDAY AND SUNDAY.

AFTER THE SHORT WAVE TROUGH SHIFTS TO THE EAST SATURDAY...CONVECTION
IS EXPECTED TO REMAIN ACTIVE THROUGH THE REMAINDER OF THE WEEKEND.
MOISTURE WILL REMAIN IN PLAY BUT NO REAL FOCUS. RIDGE WILL AMPLIFY OVER
THE SOUTHERN PLAINS MONDAY AND THEN RETROGRADE BACK WEST TUESDAY
AND WEDNESDAY OF NEXT WEEK...SO THIS WEAKNESS WILL ALLOW SCATTERED
CONVECTION EACH AFTERNOON MONDAY THROUGH WEDNESDAY. 18

AVIATION...
A SCATTERED TO BROKEN MID-LEVEL CLOUD DECK WILL REMAIN IN PLACE
THROUGH THE OVERNIGHT HOURS. OVERALL...VFR CONDITIONS WILL BE THE
RULE DURING THIS PERIOD. TOMORROW...RAIN CHANCES WILL BE ON THE
INCREASE AS A SLOW MOVING UPPER LEVEL LOW SLIDES INTO THE REGION.
HAVE INCLUDED VCTS WORDING AFTER 12Z TO REFLECT THIS RISK.
CEILINGS WILL REMAIN IN THE VFR RANGE AT AROUND 5000 TO 8000 FEET.
ANY CONVECTION COULD LEAD TO BRIEF PERIODS OF MVFR AND POSSIBLY
IFR RESTRICTIONS. 32

MARINE...
WIND AND WAVE REGIME SHOULD BE FAIRLY BENIGN WITH THE POSSIBLE
EXCEPTION OF FRIDAY NIGHT AND SATURDAY...WHEN A SHORTWAVE PASSES
THROUGH THE AREA AND TIGHTENS THE GRADIENT SLIGHTLY. DO NOT
ANTICIPATE ANY HEADLINES AT THIS TIME. 18

DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT.

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  67  84  70  90 /  40  90  60  70
BTR  72  87  73  90 /  50  90  60  70
ASD  71  88  72  91 /  40  80  60  70
MSY  75  88  75  90 /  50  80  60  70
GPT  71  88  75  89 /  20  70  50  70
PQL  69  88  72  90 /  20  70  50  70

&&

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

$$








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