298
FXUS64 KLCH 031107
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
607 AM CDT SAT OCT 3 2026
..NEW AVIATION
KEY MESSAGES
- HIGH RAIN CHANCES CAN BE EXPECTED OVER THE WEEKEND AS AN UPPER
LEVEL TROUGH, WEAK SURFACE BOUNDARY, AND TROPICAL WAVE ALL MERGE
INTO A VERY MOIST AIR MASS OVER THE REGION.
- TRENDS SHOW A HIGH PROBABILITY OF A "WETTING" RAIN DURING THE
WEEKEND THAT WOULD HELP WITH FIRE WEATHER AND DROUGHT CONCERNS.
- THERE IS SOME POTENTIAL FOR HEAVY RAINFALL DURING THE WEEKEND
ESPECIALLY OVER LOWER ACADIANA AND THE ATCHAFALAYA BASIN WHERE
THE BEST MOISTURE AND LIFT WILL BE LOCATED.
- A SECONDARY SURFACE FRONT ON MONDAY WILL BRING LOWER RAIN
CHANCES AND SLIGHTLY COOLER TEMPERATURES CLOSER TO THE CLIMO
NORM FOR EARLY NEXT WEEK.
DISCUSSION
(TODAY THROUGH FRIDAY)
ISSUED AT 1256 AM CDT SAT OCT 3 2026
EVENING UPPER AIR ANALYSIS DEPICTS RIDGING ALOFT ACROSS THE
SOUTHEASTERN CONUS, WITH SOUTHERN LA AND SOUTHEAST TX ON THE WESTERN
PERIPHERY OF THIS RIDGE. AN UPPER-LEVEL LOW WAS LOCATED OVER THE
SOUTHWESTERN GULF, WITH AN INVERTED TROUGH EXTENDING TO ITS
NORTHEAST ALONG WITH RICH TROPICAL MOISTURE. MEANWHILE, THE UPPER
LEVEL LOW OVER THE CENTRAL US HAS NOW LIFTED OFF TO THE NORTHEAST,
LEAVING A WEAK SHEAR AXIS OVER THE CENTRAL AND SOUTHERN PLAINS. RICH
MOISTURE WITH CONNECTIONS TO THE TROPICAL EASTERN PACIFIC IS IN
PLACE AHEAD OF THIS FEATURE. WEAK SURFACE TROUGHING IS EVIDENT OVER
THE CENTRAL US WITH A FRONTAL BOUNDARY ANALYZED FROM SOUTH TEXAS
NORTHEASTWARD INTO THE SOUTHERN APPALACHIANS. A VERY MOIST AIRMASS
IS ALREADY IN PLACE OVER THE CWA, WITH THE 00Z LCH SOUNDING
REPORTING PWAT OF 2.3 INCHES, WELL ABOVE 90TH PERCENTILE AND RIGHT
AROUND THE DAILY MAXIMUM MOVING AVERAGE FOR EARLY OCTOBER.
LOW-LEVEL EASTERLY FLOW WILL COMBINE WITH HIGHER THAN NORMAL HIGH
TIDES TO ALLOW FOR ONE MORE NIGHT OF UNUSUALLY HIGH WATER LEVELS.
GUIDANCE INDICATES LEVELS MAY REACH UP TO 1.5 FEET ABOVE MHHW
TONIGHT, WITH PEAK LEVELS OCCURRING AROUND 1 AM ALONG THE COAST AND
CLOSER TO EARLY MORNING HOURS FOR AREAS ALONG SABINE AND CALCASIEU
LAKES. A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR THESE AREAS TO
ACCOUNT FOR THIS THREAT. WATER LEVELS WILL RECEDE SATURDAY MORNING
WITH THE DIURNAL TIDE CYCLE AS WINDS TURN MORE OFFSHORE.
THE GULF INVERTED TROUGH IS ANTICIPATED TO MOVE NORTHWARD AND
APPROACH THE GULF COAST THIS WEEKEND, WHILE THE UPPER LEVEL SHEAR
AXIS AND ASSOCIATED FRONTAL BOUNDARY OVER TEXAS SLOWLY PUSH TO THE
SOUTHEAST ACROSS LOUISIANA. THIS WILL RESULT IN ALREADY ANOMALOUS
MOISTURE INCREASING EVEN FURTHER, WITH PWAT OVER THE CWA CLIMBING TO
2.4-2.6 INCHES. THERE IS VERY HIGH CONFIDENCE IN THIS EXTREMELY
ANOMALOUS MOISTURE WITH ESSENTIALLY THE ENTIRE LREF ENSEMBLE
DISTRIBUTION FOR PWAT EXCEEDING CLIMATOLOGICAL 99TH PERCENTILE BY
SATURDAY EVENING. IN ADDITION, A WEAK 300 MB JET STREAK IS EXPECTED
TO DEVELOP OVER THE MID-SOUTH, PLACING SOUTHERN LOUISIANA IN THE
RIGHT ENTRANCE REGION, WHICH WILL HELP ENHANCE LIFT.
WITH MULTIPLE WEAK FORCING MECHANISMS AND A VERY MOIST ENVIRONMENT,
WIDESPREAD SHOWERS ARE EXPECTED TO DEVELOP DURING THE DAY ON
SATURDAY. THE TROPICAL AIRMASS WILL ALLOW FOR VERY EFFICIENT WARM
RAIN PROCESSES, WITH MODEL SOUNDINGS DEPICTING WARM CLOUD LAYER
DEPTHS GREATER THAN 15 KFT, MID LEVEL RH CONSISTENTLY IN EXCESS OF
80 PERCENT, AND TALL SKINNY CAPE PROFILES. STORM MOTIONS WILL BE
SLOW AT LESS THAN 10 KT, ALLOWING HEAVY RAINFALL OVER THE SAME AREAS
FOR LONGER TIME PERIODS. WHILE THIS SUGGESTS A FLASH FLOOD THREAT,
THERE WILL ALSO BE A NUMBER OF LIMITING FACTORS THAT WILL HELP
REDUCE THIS THREAT FOR MUCH OF OUR CWA. THE INVERTED TROUGH IS
LIKELY TO STALL OUT OVER THE NORTHERN GULF COAST AND SOUTHEASTERN
LOUISIANA, CONFINING THE BEST LIFT AND MOISTURE TO THIS AREA. THERE
ALSO REMAINS CONSIDERABLE UNCERTAINTY IN THE AMOUNT OF INSTABILITY
THAT WILL BE REALIZED SATURDAY, AS MORNING CLOUD COVER WILL LIKELY
BE WIDESPREAD. HREF MEAN SBCAPE FOR SATURDAY AFTERNOON IS AROUND 600-
800 J/KG, WITH GREATER VALUES TOWARDS THE COAST, BUT THERE IS
CONSIDERABLE SPREAD IN THE DISTRIBUTION WITH THE 25TH-75TH
PERCENTILE RANGE FROM AROUND 300 TO 1200 J/KG. IF INSTABILITY
REMAINS LIMITED, RAINFALL MAY END UP BEING MORE STRATIFORM IN NATURE
WITH LOWER RAINFALL RATES AND LESS OF A FLOOD CONCERN. FINALLY, DRY
ANTECEDENT CONDITIONS AND ONGOING MODERATE TO SEVERE DROUGHT MEAN
THAT SOILS WILL BE ABLE TO ABSORB A GOOD AMOUNT OF RAINFALL, WITH 3
HR FFG CURRENTLY ANALYZED AROUND 4 TO 6 INCHES ACROSS MOST OF THE
CWA.
THE AREAS OF HIGHEST CONCERN FOR FLASH FLOODING WILL BE AREAS NEAR
AND TO THE SOUTHEAST OF THE SURFACE BOUNDARY, IN GREATER PROXIMITY
TO THE INVERTED TROUGH, AND WHERE THE GREATEST MOISTURE WILL BE
PRESENT, THOUGH WITH SUCH ANOMALOUS MOISTURE IN PLACE, ANY ACTIVITY
THAT DEVELOPS WILL NEED TO BE MONITORED. ACCORDINGLY, FOR SATURDAY,
WPC HAS A SLIGHT RISK (LEVEL 2/4) OF EXCESSIVE RAINFALL FOR AREAS
SOUTHEAST OF ROUGHLY AN INTRACOASTAL CITY-BATON ROUGE LINE, WITH A
MARGINAL RISK (LEVEL 1/4) ENCOMPASSING THE REST OF THE CWA. THE
FLOOD RISK LOOKS A BIT LOWER FOR OUR CWA ON SUNDAY AS THE SURFACE
BOUNDARY CONTINUES DRIFTING EAST OVER SOUTHEASTERN LOUISIANA AND
SLIGHTLY DRIER AIR BEGINS TO MOVE INTO NORTHWESTERN PORTIONS OF OUR
AREA.
FORECAST RAINFALL AMOUNTS FOR THE SATURDAY THROUGH SUNDAY TIME FRAME
ARE GENERALLY 0.5 TO 1.5 INCHES ACROSS MOST OF THE AREA, EXCEPT FOR
THE VICINITY OF THE LOWER ATCHAFALAYA BASIN WHERE TOTALS CLOSER TO
THE 2-3 INCH RANGE ARE FORECAST. REASONABLE WORST CASE (NBM 90TH
PERCENTILE) TOTALS ARE IN THE 2-5 INCH RANGE FOR MOST AREAS, UP TO 4-
8 INCHES IN THE LOWER ATCHAFALAYA BASIN. WITH THE CLOUD COVER AND
RAINFALL, HIGH TEMPERATURES WILL BE IN THE LOW TO MID 80S THIS
WEEKEND, WITH OVERNIGHT LOWS IN UPPER 60S TO LOW 70S.
A WEAK MID-LATITUDE SHORTWAVE TROUGH WILL ALLOW A SECONDARY COLD
FRONT TO PUSH SOUTHWARD THROUGH THE CWA MONDAY INTO TUESDAY, WITH
HIGH PRESSURE EXPECTED TO BUILD ACROSS THE EASTERN CONUS IN ITS
WAKE. THIS SHOULD ALLOW SOME DRIER AIR TO PUSH INTO THE CWA, LARGELY
ENDING RAIN CHANCES THROUGH THE FIRST HALF OF NEXT WEEK. AFTERNOON
HIGH TEMPERATURES LOOK TO BE IN THE MID 80S, WITH OVERNIGHT LOWS IN
THE 60S.
64/SILAS
AVIATION
(12Z TAFS)
ISSUED AT 554 AM CDT SAT OCT 3 2026
COOL FRONT WILL APPROACH AND BEGIN SLOWLY MOVING NEAR THE TX/LA
STATE LINE TODAY. AT THE SAME TIME, A TROPICAL WAVE WILL BE MOVING
OVER THE NORTH GULF. THE COMBINATION OF THESE TWO FEATURES WILL
ALLOW FOR SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE OVER THE
NORTHWEST GULF. EXPECT PERIODS OF CONVECTION WITH HEAVY DOWNPOURS
LIKELY. A PERSISTENT STRATIFORM RAIN IS EXPECTED TO MOVE ONSHORE
TO ALL COASTAL TERMINALS SOMETIME AROUND 06Z SUNDAY OR SO.
DEEP TROPICAL MOISTURE WILL ACCOMPANY THE WAVE, ALLOWING FOR
CEILINGS TO DROP THROUGHOUT THE PERIOD. MVFR CIGS ARE ANTICIPATED
BY 18 TO 20Z WITH A PROGRESSIVE DROP INTO THE LIFR RANGE BY THE
END OF THE TAF PERIOD.
WINDS TODAY WILL TURN IN RESPONSE TO THE FRONTAL BOUNDARY AND
TROPICAL WAVE, SO SOME VARIABILITY MAY EXIST. WINDS WILL PREVAIL
FROM THE NORTHEAST THROUGH THE MORNING, BECOMING MORE NORTHERLY
FROM MIDDAY ONWARD. WINDS MAY BECOME BREEZY DURING DAYTIME HOURS
TODAY IN RESPONSE TO THESE PRESSURE FEATURES AS WELL.
11/CALHOUN
MARINE
ISSUED AT 1256 AM CDT SAT OCT 3 2026
MODERATE NORTHEAST WINDS AND MODERATE SEAS ARE EXPECTED THROUGH THE
WEEKEND AS MULTIPLE DISTURBANCES APPROACH THE AREA. WINDS OF 10-20
KT AND SEAS 2-5 FEET ARE ANTICIPATED THROUGH THE WEEKEND, AND SMALL
CRAFT ARE URGED TO EXERCISE CAUTION. NUMEROUS SHOWERS AND
THUNDERSTORMS ARE ALSO EXPECTED THROUGH THIS TIME AND WILL CAUSE
LOCALLY HIGHER WINDS AND WAVES. A SECOND FRONTAL BOUNDARY SHOULD
PUSH THROUGH THE COASTAL WATERS MONDAY, BRINGING RAIN CHANCES TO AN
END ALONG WITH A PERIOD OF MODERATE TO STRONG OFFSHORE FLOW.
FIRE WEATHER
ISSUED AT 1256 AM CDT SAT OCT 3 2026
A VERY MOIST AIRMASS IS EXPECTED TO SIT OVER THE REGION THROUGH THE
WEEKEND. NUMEROUS SHOWERS ARE EXPECTED BOTH SATURDAY AND SUNDAY,
WITH AFTERNOON MINIMUM RH VALUES IN THE 65 TO 75 PERCENT RANGE. ALL
AREAS ARE LIKELY TO SEE A WETTING RAIN OF AT LEAST 0.25 INCHES,
WHICH SHOULD REDUCE FIRE DANGER AND MAY ALLOW FOR SOME IMPROVEMENT
IN DROUGHT CONDITIONS. DRIER CONDITIONS RETURN ON MONDAY.
LCH WATCHES/WARNINGS/ADVISORIES
LA...COASTAL FLOOD ADVISORY UNTIL 7 AM CDT THIS MORNING FOR LAZ073-
074-252>254.
COASTAL FLOOD ADVISORY UNTIL 11 AM CDT THIS MORNING FOR LAZ241.
TX...COASTAL FLOOD ADVISORY UNTIL 7 AM CDT THIS MORNING FOR TXZ615.
COASTAL FLOOD ADVISORY UNTIL 11 AM CDT THIS MORNING FOR TXZ616.
GM...NONE.
PUBLIC/FIRE/MARINE...64
AVIATION...11
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