Area Forecast Discussion
Issued by NWS Lake Charles, LA

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000
FXUS64 KLCH 261152
AFDLCH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
652 AM CDT SUN APR 26 2015

.DISCUSSION...
FOR THE 12Z TAF PACKAGE.

&&

.AVIATION...
WIDESPREAD FOG AND/OR LOW CIGS ACROSS THE REGION THIS MORNING
YIELDING LIFR AT ALL TERMINALS. A FEW HRS OF HEATING SHOULD RESULT
IN IMPROVING CONDITIONS...WITH ALL SITES EXPECTED TO BE VFR BY MID
TO LATE MORNING. VFR TO PREVAIL THROUGH THE AFTERNOON AND INTO THE
EVENING WITH GENERALLY LIGHT SOUTHERLY WINDS. CONSIDERABLE LOW
LEVEL MSTR WILL STILL BE IN PLACE...HOWEVER...WITH LOW CIGS AND
VSBY RESTRICTIONS LIKELY TO RETURN. WINDS ALOFT ARE PROGGED TO BE
A BIT MORE ROBUST...WHICH MAY HELP MITIGATE THE FOG POTENTIAL.
CONVECTIVE POTENTIAL ON MONDAY LOOKS TO BE JUST BEYOND THIS FCST
PERIOD.

13

&&

.PREV DISCUSSION... /ISSUED 551 AM CDT SUN APR 26 2015/

UPDATE...
HAVE GONE AHEAD AND ISSUED A DENSE FOG ADVISORY FOR MOST OF
SOUTHWEST LOUISIANA AND SOUTHEAST TEXAS. HAVE RECEIVED SEVERAL
CALLS FROM VARIOUS INDIVIDUALS REGARDING THE FOG DURING THE PAST
HOUR AND OBS SEEM TO INDICATE VSBYS OF ONE QUARTER OF A MILE
BECOMING MORE WIDESPREAD. VSBYS HAVE BEEN A LITTLE HIGHER ACRS W
CNTL AND CNTL LA BUT WILL CONTINUE TO MONITOR THESE LOCATIONS FOR
POSSIBLE EXTENSION. 24

PREV DISCUSSION... /ISSUED 519 AM CDT SUN APR 26 2015/

SYNOPSIS...
UA PATTERN THIS MORNING MARKED BY SOMEWHAT DRY W/SW FLOW BETWEEN THE
IMPULSE THAT BROUGHT THE SHRA/TSRA TO THE AREA YESTERDAY MORNING AND
OUR NEXT WEATHER MAKER UPSTREAM: A DIGGING TROF W OF THE ROCKIES.
SFC HIGH PRES EAST OF THE REGION IS KEEPING A MOIST SLY FLOW OVER
THE REGION WHILE A COOL FRONT IS ORIENTED WEST TO EAST ACRS CNTL OK
INTO CNTL ARK. REGIONAL RADARS ARE RELATIVELY QUIET THIS MORNING
COMPARED TO THE PAST FEW MORNINGS. AREAS OF FOG...INCLUDING SOME
PATCHY DENSE FOG...HAVE DEVELOPED ACRS MUCH OF THE AREA THIS
MORNING.

DISCUSSION...
WILL CONTINUE TO MONITOR FOR A DENSE FOG ADVISORY THIS MORNING.
HAVE HELD OFF ISSUANCE ATTM AS VSBYS HAVE BEEN NOT ONLY VRBL ACRS
THE AREA BUT HAVE ALSO BEEN FLUCTUATING UP AND DOWN. A RECENT
CHECK OF AREA TRAFFIC CAMERAS ALSO INDICATES THE PATCHY NATURE OF
THE FOG. EITHER WAY...FOG IS EXPECTED TO LIFT BY MID-MORNING WITH
A RELATIVELY DRY DAY EXPECTED. WITH SOMEWHAT DRIER AIR OVER THE
REGION...SKIES SHOULD BE PARTLY TO MOSTLY SUNNY TODAY AND THIS
WILL ALLOW TEMPERATURES TO WARM INTO THE MIDDLE 80S TO NEAR 90.
ALTHOUGH RAIN CHANCES WILL BE LOW...A FEW ISLTD SHOWERS OR STORMS
WILL BE POSSIBLE LATER THIS AFTN ESPECIALLY ACRS SE TX AS MOISTURE
BEGINS TO RETURN TO THE REGION.

THE BIGGER STORY WILL BE THE POTENT UPPER LVL SYSTEM MOVING INTO
TX ON MONDAY. MOISTURE WILL INCREASE SIGNIFICANTLY IN ADVANCE OF
THIS SYSTEM WILL PRECIP WATER VALUES APPROACHING 2 INCHES. THE
AREA IS STILL PROGGED TO BE IN A FAVORABLE ZONE WITH MID/UPR JET
MAX APPROACHING THE AREA...DIVERGENT FLOW ALOFT...STEEPENING
LAPSE RATES AND A VEERING WIND PROFILE AS THE MID AND UPR LOW MOVE
ACRS NRN TX. AT THE SFC...LOW PRES WILL DEVELOP OVER SE TX ALONG A
COLD FRONT THAT WILL SAG SOUTH ACRS THE REGION. THIS COMBINATION
OF FACTORS WILL BRING AN INCREASE IN SHOWERS AND THUNDERSTORMS
LATE SUNDAY NIGHT INTO MONDAY MORNING...WITH SCT TO NMRS SHOWERS
AND STORMS EXPECTED THROUGH MONDAY NIGHT. SOME STORMS WILL ALSO BE
CAPABLE OF BECOMING SVR...ESPECIALLY AS INSTABILITY INCREASES
DURING THE DAY MONDAY. SPC CONTINUES TO SHOW THE AREA IN A SLIGHT
RISK FOR SVR STORMS...WITH DAMAGING WINDS AND HAIL THE LIKELIEST
THREATS AS WELL AS A FEW TORNADOES GIVEN DECENT LOW LVL SHEAR IN
PLACE. ON TOP OF THIS...STORMS WILL BE CAPABLE OF PRODUCING VERY
HEAVY RAINFALL AND THIS COULD LEAD TO THE POSSIBILITY OF LOCALIZED
FLOODING ESPECIALLY IF STORMS BEGIN TO TRAIN ACRS AN AREA.

THE ACTIVE PATTERN WILL CONTINUE INTO THE EVENING...BUT THE SVR
THREAT WILL BEGIN TO DIMINISH AS THE SFC LOW TREKS EAST ACRS THE
COASTAL ZONES...AND NLY LOW LVL FLOW BEGINS TO UNDERCUT THE
AIRMASS. RAIN CHCS WILL BEGIN TO DIMINISH FM WEST TO EAST TUESDAY
AS THE SFC LOW MOVES EAST AND THE MID/UPR SYSTEM CROSSES THE LOWER
MS VALLEY. BEHIND THIS SYSTEM...DRIER AND COOLER WEATHER WILL MOVE
INTO THE REGION AS SFC HIGH PRES BUILDS INTO THE AREA AND A DRY
NWLY FLOW DEVELOPS ALOFT. THIS DRY PATTERN IS EXPECTED TO CONTINUE
INTO THE WEEKEND. GLOBAL MODELS DEPICT A SHORTWAVE DROPPING SOUTH
ON THE BACKSIDE OF THE MEAN ERN CONUS TROF ON THURSDAY...BUT
CONDITIONS SHOULD REMAIN TOO DRY TO GENERATE ANY RAIN.

WARM AND MUGGY CONDITIONS WILL CONTINUE TODAY AND TONIGHT. FOR
MONDAY....AFTN HIGHS WILL BE TEMPERED BY THE INCREASE IN CLOUDS
AND SHOWERS WITH HIGHS HOLDING IN THE 70S OR POSSIBLY CLIMBING TO
NR 80. COOLER AIR WILL BEGIN TO INFILTRATE THE AREA TUESDAY WITH
HIGH TEMPERATURES IN THE UPR 60S ACRS THE NRN TIER OF ZONES TO
LOWER/MID 70S ALONG THE I-10 CORRIDOR. THE COOLER TEMPERATURES
WILL PERSIST THROUGH FRIDAY WITH LOWS IN THE 50S AND HIGHS IN THE
70S. A GRADUAL WARMING TREND WILL DEVELOP FROM FRIDAY INTO THE
WEEKEND AS THE SFC HIGH BEGINS TO SLIDE OFF TO THE EAST.

24

MARINE...
MDT SLY FLOW WILL PERSIST THROUGH MONDAY WITH HIGH PRES EAST OF
THE REGION. A STRONG DISTURBANCE WILL CROSS THE AREA MONDAY INTO
TUESDAY...AND SHOWER AND THUNDERSTORM CHANCES WILL AGAIN INCREASE
FOR EARLY THIS WEEK. SOME STORMS ASSOCIATED WITH THIS SYSTEM COULD
BECOME STRONG MONDAY AND MONDAY NIGHT...BRINGING THE POTENTIAL FOR
STRONG GUSTY WINDS...FREQUENT LIGHTNING AND VERY HEAVY RAINFALL. SFC
LOW PRES WILL DEVELOP OVER TX MONDAY IN RESPONSE TO THE PASSING
TROF ALOFT. THIS LOW IS EXPECTED TO CROSS THE COASTAL WATERS
MONDAY NIGHT...WITH A TRAILING COLD FRONT MOVING THROUGH ON
TUESDAY. BEHIND THE FRONT...RAIN CHCS WILL COME TO AN END...WITH
MODT TO STRONG NLY WINDS DEVELOPING AND SMALL CRAFT ADVISORY
CONDITIONS WILL BE POSSIBLE TUESDAY NIGHT INTO WEDNESDAY.

24

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  90  65  75  59 /  20  50  70  70
LCH  85  71  79  64 /  20  60  70  60
LFT  88  70  79  67 /  20  60  70  70
BPT  86  73  80  64 /  20  70  70  60

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR LAZ030>033-
     041>045-052>055-073-074.

TX...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR TXZ180-201-
     215-216-259>262.

GM...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR GMZ430-432-
     435.

&&

$$



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