Area Forecast Discussion
Issued by NWS Lake Charles, LA

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000
FXUS64 KLCH 041207
AFDLCH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
707 AM CDT TUE AUG 4 2015

.DISCUSSION...
FOR 12Z TAF ISSUANCE.

&&

.AVIATION...
MAIN ITEMS OF CONCERN FOR AVIATION INTERESTS THIS MORNING APPEAR
TO BE VISIBILITY AND POPS AT A FEW LOCATIONS. ATTM A FEW LOCATIONS
ARE SHOWING SLIGHT RESTRICTIONS TO VISIBILITY WHICH COULD PERSIST
NEXT HOUR OR SO BEFORE GOOD HEATING COMMENCES AND THE LIGHT FOG
BURNS OFF. LOCAL 88DS SHOW A SLOWLY-EXPANDING AREA OF CONVECTION
OVER THE COASTAL WATERS ALONG A LOW-LEVEL CONVERGENCE ZONE WHICH
IS PROGGED TO REMAIN OFFSHORE THIS MORNING. HOWEVER BY AFTERNOON A
LITTLE BETTER MOISTURE ALOFT IS PROGGED TO ENCROACH OVER LOWER
ACADIANA WHICH COULD ALLOW A LITTLE MORE CONVECTION TO DEVELOP
THERE...AND VCTS CONTINUES TO BE CARRIED AT KLFT/KARA TO ACCOUNT.

25

&&

.PREV DISCUSSION... /ISSUED 315 AM CDT TUE AUG 4 2015/

DISCUSSION...
EARLY THIS MORNING RADAR SHOWED SHOWER AND THUNDERSTORM ACTIVITY
15 TO 50 NM OFFSHORE BETWEEN GRAND CHENIER AND THE LOWER
ATCHAFALAYA RIVER. THIS ACTIVITY WAS DRIFTING EAST TO NORTHEAST.

SURFACE OBSERVATIONS ACROSS THE REGION WERE INDICATING THAT MARINE
AIR HAD BEGUN TO MIGRATE NORTHWARD INTO SOUTHWEST...SOUTH CENTRAL
AND PARTS OF CENTRAL LOUISIANA WITH DEWPOINTS 2 TO 5 DEGREES
HIGHER THAN THIS TIME YESTERDAY. 00Z TUE SOUNDING SHOWED THAT
THERE WAS CAPPING OR WARM AIR APPROXIMATELY 9500 FT TO 12420 FT
ABOVE THE SURFACE. LITTLE IF ANY CONVECTION WAS OBSERVED INLAND
YESTERDAY AND IT APPEARED THAT THIS WARM CAP AND WEAK SEA BREEZE
GENERALLY RESULTED IN JUST A HOT MONDAY.

TODAY IN THE UPPER LEVELS...WEAK RIDGING ALOFT WILL CONTINUE WITH
UPPER LEVEL WEAK NORTHERLY FLOW. SOUNDING PROFILE FORECAST OFF THE
GFS MODEL INDICATE THAT WITH TIME PRECIPITABLE WATER VALUES WILL
BEGIN TO CLIMB THIS AFTERNOON INTO THE 1.60 TO NEAR 2" PW RANGE
ACROSS THE REGION WHICH SHOULD TRANSLATE INTO SLIGHT CHANCE OF
RAIN TODAY ACROSS THE REGION WITH PERHAPS SCATTERED ACTIVITY OVER
SOUTH CENTRAL LOUISIANA WHERE THE SEA BREEZE MIGHT BE MORE ACTIVE.
IN GENERAL THOUGH...THE WEAK UPPER LEVEL RIDGE WILL CONTINUE TO
SUPPRESS RAIN CHANCES AS THE WARM CAP REMAINS INTACT.

LOOKING INTO WEDNESDAY...FEEL CONFIDENT THAT INCREASED MOISTURE
AND SLIGHT WESTWARD REGRESSION OF THE UPPER LEVEL RIDGE WILL JUST
BE ENOUGH TO ALLOW FOR INCREASED RAIN CHANCES. WENT AHEAD AND
UPPED THE POPS FOR WEDNESDAY AS THE SEA BREEZE AND DAYTIME
HEATING COMBINE TO TRIGGER AND DISTRIBUTE MORE RAINFALL ACROSS THE
THE SOUTHERN HALF OF THE AREA. GFS MOS GUIDANCE APPEARED TO BE
SIGNALING AT LEAST A TEMPORARY WEAKENING OF THE RIDGE ON WEDNESDAY.

THE UPPER LEVEL RIDGE WILL REMAIN DOMINANT THURSDAY THROUGH
SATURDAY SO EXPECT LOWER POPS ACROSS THE REGION. PERHAPS SOME
WEAKENING OF THE RIDGE WILL RETURN SUNDAY AND MONDAY ALLOWING FOR
SLIGHTLY BETTER CHANCES OF RAIN ACROSS SOUTH CENTRAL LOUISIANA.

FOR THE MOST...SUMMER STILL IS IN FULL SWING. EVEN THOUGH
TEMPERATURES MAY BE A FEW DEGREES LOWER TODAY AND WEDNESDAY...LOOK
FOR WARMER TEMPERATURES FOR THE REST OF THE FORECAST PACKAGE.

MARINE...
LIGHT SOUTHERLY FLOW AND LOW SEAS WILL CONTINUE ACROSS THE REGION
AS SURFACE RIDGE OF HIGH PRESSURE BUILDS WESTWARD INTO THE
NORTHWEST GULF OF MEXICO.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  98  76  96  76 /  20  10  20  10
LCH  95  78  93  78 /  20  10  30  10
LFT  95  77  94  77 /  30  10  40  10
BPT  96  77  94  78 /  20  10  30  10

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&

$$


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