590  
FXUS64 KLCH 221738  
AFDLCH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LAKE CHARLES LA  
1238 PM CDT FRI OCT 22 2021  
   
DISCUSSION
 
 
FOR 10/22/2021 18Z TAF ISSUANCE.  
 

 
   
AVIATION
 
 
A WEAK FRONTAL BOUNDARY THAT SLID THROUGH THE REGION OVERNIGHT IS  
NOW LARGELY STATIONARY NEAR THE COAST. AS A RESULT, WINDS AT THE  
TERMINALS ARE GENERALLY EASTERLY, AND AT TIMES LIGHT AND VARIABLE.  
THROUGH THE DAY, SHOULD CONTINUE TO SEE A MIX OF SOME VFR CU  
~3500 TO 6000 FT ALONG WITH SOME HIGHER LEVEL CIRRUS FILTERING  
THROUGH. GUIDANCE SUGGESTS AN OUTSIDE SHOT AT A WIDELY ISOLATED  
SHOWER OR TWO ALONG THE I-10 CORRIDOR THIS AFTERNOON AS THE  
BOUNDARY WASHES OUT, BUT COVERAGE IS FAR TOO LOW TO INCLUDE ANY  
MENTION IN THE TAFS. BOUNDARY CONTINUES TO WASH OUT OVERNIGHT WITH  
SURFACE WINDS BECOMING LIGHT AND VARIABLE TO CALM. CONDITIONS  
ONCE AGAIN LOOK FAVORABLE FOR FOG TO DEVELOP AFTER MIDNIGHT GIVEN  
THE ABUNDANT LOW LEVEL MOISTURE AND VERY LIGHT LOW LEVEL WINDS.  
GUIDANCE SUGGESTS FOG DEVELOPMENT AFTER MIDNIGHT AT  
BPT/LCH/LFT/ARA, BECOMING MORE DENSE PRIOR TO SUNRISE. A LITTLE  
LESS CONFIDENCE AT AEX, BUT WILL LIKELY SEE SOME VIS REDUCTIONS AS  
WELL. AFTER SUNRISE, EXPECT FOG TO GRADUALLY LIFT INTO A BKN MVFR  
STRATUS DECK FOR A TIME, WITH WINDS PICKING UP OUT OF THE SSE.  
 
50  
 

 
   
PREV DISCUSSION
 
/ISSUED 1030 AM CDT FRI OCT 22 2021/  
 
UPDATE...  
 
A WEAK SURFACE BOUNDARY HAS WORKED THROUGH THE REGION OVERNIGHT,  
STALLING IN THE COASTAL WATERS THIS MORNING. KLCH SHOWING SOME  
VERY ISOLATED CONVECTION WITH THIS, WITH GOES-16 VISIBLE ALSO  
SHOWING A LINE OF AGITATED CU LIKELY DEMARCATING THE BOUNDARY.  
WITH THE BOUNDARY TO THE SOUTH, SOME DRIER AIR HAS MANAGED TO  
FILTER INTO CENLA, WITH DEW POINT READINGS IN THE MID 50S. CLOSER  
TO THE I-10 CORRIDOR, LOW LEVEL MOISTURE REMAINS QUITE RICH, AND  
AS A RESULT DEW POINTS REMAIN CLOSER TO 70. NOT EXPECTING TOO MUCH  
DRY AIR TO ADVECT FURTHER SOUTH, AND IF ANYTHING MIGHT SEE THE DEW  
POINTS IN CENLA CREEP BACK UP A BIT AS THE STALLED BOUNDARY BEGINS  
TO WASH OUT AND WINDS BEGIN TO SHIFT EASTERLY AND THEN BACK TO  
SOUTHERLY. NO REAL CAA BEHIND THE AFOREMENTIONED BOUNDARY EITHER,  
SO AFTERNOON HIGHS STILL EXPECTED TO BE WELL ABOVE SEASONAL  
NORMALS. COMBINATION OF SURFACE HIGH TO OUR NORTH AND 850MB RIDGE  
CENTERED ATOP THE REGION WILL HELP KEEP PWATS A BIT MORE IN CHECK,  
AND ALSO HELP TO SUPPRESS ALL BUT A FEW WIDELY ISOLATED  
THUNDERSHOWERS TODAY. OVERALL, ONLY MADE A FEW MINOR TWEAKS TO THE  
INHERITED GRIDS TO ACCOUNT FOR SHORT TERM TRENDS AND GUIDANCE.  
 
50  
 
PREV DISCUSSION... /ISSUED 425 AM CDT FRI OCT 22 2021/  
 
DISCUSSION...  
 
SHORT TERM [TODAY THROUGH SUNDAY NIGHT]...  
 
WX MAP SHOWS WEAK COOL FRONTAL BOUNDARY ACROSS C LA WITH A LIGHT  
NORTHEAST WIND AND SLIGHTLY LOWER DEWPOINTS BEHIND THE FRONT. AHEAD  
OF THE BOUNDARY LIES CALM WINDS AND AREAS OF DENSE FOG ALONG AND  
SOUTH OF THE I-10 CORRIDOR. DENSE FOG ADVISORY REMAINS IN EFFECT  
THROUGH 9 AM. LATER THIS AFTERNOON, SLIGHT CHANCE OF SHOWERS AND  
PERHAPS A THUNDERSTORM WITH THE WEAK FRONT, STILL QUESTIONABLE IF  
IT WILL REACH THE COAST OR STALL ALONG THE I-10 CORRIDOR. CHANCES  
REMAIN AT A LOW 20%. WHAT'S CERTAIN IS MUCH ABOVE NORMAL TEMPERATURES  
WITH AFTERNOON HIGHS REACHING THE MID TO UPPER 80S. LOWS TONIGHT  
IN THE LOWER 60S BEHIND THE FRONT ACROSS C LA/INLAND SE TX, BUT  
REMAINING IN THE UPPER 60S TO LOWER 70S FURTHER SOUTH.  
 
FOR SATURDAY, A WEAK SHORTWAVE WITHIN THE ZONAL FLOW ALOFT WILL  
LIKELY IMPACT THE REGION GIVING SCATTERED AFTERNOON SHOWERS AND A  
FEW THUNDERSTORMS. GIVEN THE MOISTURE AVAILABILITY AND INSTABILITY  
WITH AFTERNOON HIGHS IN THE MID TO UPPER 80S ONCE AGAIN, 30-40%  
SEAMS REASONABLE. HAD TO LOWER THE NATIONAL BLENDED GUIDANCE WHICH  
WAS A BIT TOO HIGH GOING OVER 50%.  
 
SUNDAY, NOT MUCH CHANGE EXPECTED WITH ANOTHER WEAK SHORTWAVE TO  
GIVE ISOLATED TO SCATTERED SHOWERS ACROSS THE COASTAL WATERS  
DURING THE MORNING, AND DEVELOPING INLAND DURING THE AFTERNOON  
HOURS. CHANGES AGAIN 30-40%, AND BELOW THE OVERDONE NATIONAL  
BLENDED GUIDANCE. HIGHS ONCE AGAIN IN THE MID TO UPPER 80S.  
 
DML  
 
LONG TERM [MONDAY THROUGH SATURDAY 12Z]...  
 
THE HEAT AND HUMIDITY CONTINUE TO CLIMB AT THE BEGINNING OF THE  
FORECAST PERIOD WITH SOUTHERLY WINDS OFF THE GULF OF MEXICO MONDAY  
AND TUESDAY. WITH HIGH TEMPERATURES IN THE MID TO UPPER 80S COMBINED  
WITH DEWPOINTS IN THE LOW TO MID 70S, THE OUTDOORS WILL FEEL  
DOWNRIGHT OPPRESSIVE. CONDITIONS MONDAY AND TUESDAY WILL SUPPORT THE  
CHANCE FOR SHWRS AND THUNDERSTORMS, AS GULF MOISTURE AND DAYTIME  
RADIATION COULD OFFER AFTERNOON INSTABILITY.  
 
BEYOND TUESDAY, CONFIDENCE MARKEDLY DECREASES AS MODEL GUIDANCE  
CONTINUES TO STRUGGLE WITH THE NEXT FRONTAL PASSAGE ACROSS THE US.  
AS WE GO FURTHER INTO THE WEEKEND, MODELS WILL HAVE MORE TIME TO  
RESOLVE THIS COMING SYSTEM, STAY TUNED AS THE FORECAST WILL UPDATE  
WITH LATEST TRENDS. FOR NOW, EURO AS A DEEPER SURFACE LOW SWINGING  
THROUGH THE CENTRAL US WITH THE FRONT TRAILING BEHIND IT IN THE FORM  
OF A STRONG LINE OF STORMS SWIFTLY MOVING THROUGH ON WEDNESDAY  
MORNING/AFTERNOON. THE GFS ON THE OTHER HAND, HAS THE SURFACE LOW  
MUCH FURTHER NORTH, RESULTING WITH A SLIGHTLY WEAKER BOUNDARY  
PASSING THROUGH THE AREA WHICH WOULD KEEP THE REGION MUCH DRIER ON  
WEDNESDAY. AS FOR THE FORECAST, DECIDED TO LEAN INTO THE WETTER  
OUTCOME AND KEPT POPS IN THE 40 TO 60 PERCENT RANGE WITH MODEST  
RAINFALL TOTALS. FCST PWAT VALUES IN THE 1.50 TO 1.80 INCH RANGE,  
ALONG WITH THE FORCING MECHANISM OF THE FRONTAL PASSAGE, RAIN SHOULD  
BE EXPECTED.  
 
AFTER WEDNESDAY, GUIDANCE SETTLES IN WITH MINIMAL RAIN CHANCES AS  
HIGH PRESSURE TAKES OVER AND NORTHWEST FLOW SPILLS DRY AIR DOWN INTO  
THE REGION. AFTER THE FRONT, THURSDAY MORNING COULD SEE TEMPERATURES  
IN THE UPPER 50S TO LOW 60S WITH AFTERNOON TEMPERATURES IN THE LOW  
80S.  
 
11  
 
AVIATION...  
LIFR VISIBILITIES/CEILINGS DUE TO DENSE FOG WILL CONTINUE AT  
BPT/LCH/ARA/LFT THROUGH 13-14Z, EXPECTED TO BURN OFF RAPIDLY BY  
15Z. FOR AEX, NO SIGNIFICANT RESTRICTIONS EXPECTED AS THE COOL  
FRONT HAS MOVED SOUTH OF THIS TERMINAL. LATER THIS MORNING INTO  
THE AFTERNOON HOURS, EAST NORTHEAST WINDS AROUND 6-8 KTS EXPECTED,  
WITH ONLY ISOLATED SHOWERS POSSIBLE DURING THE AFTERNOON HOURS,  
TOO LOW OF A CHANCE TO PUT VCSH IN THE TERMINALS.  
 
DML  
 
MARINE...  
THE WEAK SURFACE BOUNDARY EXPECTED TO JUST MAKE IT ACROSS THE  
COASTAL WATERS LATER THIS AFTERNOON BEFORE STALLING AND MOVING  
BACK NORTH BY SATURDAY. BRIEF OFFSHORE WINDS ACROSS THE NEAR SHORE  
WATERS, BUT MOST LIKELY, LIGHT AND VARIABLE ELSEWHERE. WINDS WILL  
QUICKLY SHIFT BACK TO AN ONSHORE DIRECTION BY TONIGHT AS THE  
FRONT WASHES OUT.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
AEX 61 86 64 86 / 10 20 10 30  
LCH 68 84 70 84 / 10 40 10 40  
LFT 68 85 69 86 / 20 20 10 40  
BPT 69 84 71 84 / 10 40 20 40  
 

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

 
 

 
 
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