552
FXUS64 KLCH 220539
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1239 AM CDT WED JUL 22 2026
..NEW DISCUSSION, AVIATION, MARINE, FIRE WEATHER
KEY MESSAGES
- TROPICAL STORM BERTHA IS EXPECTED TO MOVE WEST NEAR THE COAST OF THE
NORTHERN GULF THROUGH THURSDAY. THIS SYSTEM IS EXPECTED TO BE
ASYMMETRICAL WITH A MAJORITY OF THE IMPACTS SOUTH OF THE CENTER.
- A TROPICAL STORM WATCH IS IN EFFECT FOR THE COASTAL PARISHES
EAST OF CAMERON DUE TO A PROBABILITY OF TROPICAL STORM WIND
GUSTS WEDNESDAY NIGHT INTO THURSDAY. ISOLATED HEAVY RAINS AND
SOME POTENTIAL STORM SURGE OF 1 TO 3 FEET WILL ALSO BE POSSIBLE
IN THE WATCH AREA.
- EXTREME HEAT WARNING TODAY. THE COMBINATION OF SINKING AIR ALOFT
AS AN UPPER LEVEL RIDGE FROM THE ROCKIES BUILDS IN AND THE
OUTFLOW FROM TROPICAL STORM BERTHA WILL BRING THE POTENTIAL FOR
OPPRESSIVE HEAT. MAX AFTERNOON HEAT INDEX IS EXPECTED TO RANGE
FROM 112 TO 118 DEGREES.
- OVER THE WEEKEND INTO EARLY NEXT WEEK THE UPPER LEVEL RIDGE WILL
CONTINUE IN CONTROL WITH LIMITED RAIN CHANCES AND HOT
CONDITIONS.
DISCUSSION
(TODAY THROUGH TUESDAY)
ISSUED AT 1233 AM CDT WED JUL 22 2026
TROPICAL STORM BERTHA IS GETTING BATTERED TONIGHT BY NORTHEAST SHEAR
AND DRY CONTINENTAL AIR, TWO THINGS TROPICAL SYSTEMS DO NOT LIKE,
UPPER LEVEL SHEAR AND DRY AIR. SATELLITE AND RADAR SHOW THE CENTER
IS EXPOSED AGAIN WITH IT BECOMING DETACHED FROM THE CONVECTION AND
THE UPPER LEVEL LOW. USUALLY THESE TROPICAL SYSTEMS LIKE TO BREATHE
AT NIGHT, SO THE NEXT FEW HOURS WILL BE CRUCIAL TO SEE WHAT WILL BE
LEFT OF BERTHA.
OVER THE NEXT COUPLE OF DAYS THE WILL BE A BATTLE BETWEEN THE
STRENGTHENING UPPER LEVEL RIDGE FROM THE ROCKIES BUILDING INTO THE
CENTRAL AND SOUTHWEST US AND THE TROPICAL SYSTEM BERTHA. STEERING
CURRENTS WILL KEEP BERTHA MOVING WESTWARD NEAR OR JUST INLAND OF THE
LOUISIANA COAST. LAND INTERACTION, ALTHOUGH IT WILL BE MAINLY MARSH
LAND, AND MORE IMPORTANTLY, THE HOSTILE ENVIRONMENT FROM THE UPPER
LEVEL SHEAR AND DRY AIR SHOULD KEEP BERTHA ON A SLOW DECLINE AND
THERE IS STILL SOME DEBATE THAT IT MAY JUST OPEN UP INTO A WAVE BY
THE TIME IT REACHES SOUTHWEST LOUISIANA ON THURSDAY.
FIRST THING FIRST, AND IN THE IMMEDIATE TERM, HEAT WILL BE THE
ISSUE. LOOKS LIKE A REALLY GOOD DAY FOR SUBSIDENCE AND SINKING AIR
AS THE COMBINATION APEX FROM THE UPPER LEVEL RIDGE AND OUTFLOW FROM
BERTHA SHOULD BE MAXIMIZE. USUALLY IN THESE SITUATION AIR
TEMPERATURES WILL SKY ROCKET, ESPECIALLY WITH AN EXPECTED LACK OF
CLOUD COVER, WITH AIR TEMPERATURES NEARING TRIPLE DIGITS. MEANWHILE,
TROPICAL MOISTURE IN THE LOWEST LEVELS WILL BE TRYING TO MOVE IN
WITH HIGH SURFACE DEW POINTS. EVEN ACCOUNTING FOR SOME MIXING, DEW
POINTS ARE LIKELY TO BE IN THE MID TO UPPER 70S DURING MAX HEATING.
THIS WILL BRING ABOUT OPPRESSIVE HEAT AND DANGEROUS APPARENT
TEMPERATURES BETWEEN 112 AND 117 DEGREES. HEAT RISK FROM WPC IS
PINGING THE FORECAST AREA IN A MAJOR (3 OUT OF 4) TO EXTREME (4 OUT
OF 4) ON THE SCALE. AN EXTREME HEAT WARNING WILL BE IN EFFECT.
A FEW SHOWERS OR STORMS MAY TRY TO DEVELOP LATE IN THE AFTERNOON
OVER ACADIANA WITH THE DAYTIME HEATING AND ENHANCED CONVERGENCE FROM
THE CIRCULATION OF BERTHA.
AS WE ENTER THURSDAY, THE TRACK AND STRENGTH OF BERTHA WILL BE THE
MAIN INFLUENCE ON THE WEATHER. CONSENSUS SHOWS THAT SHEAR AND DRY
AIR WILL EVENTUALLY WIN THE BATTLE WITH WEAKENING SYSTEM IF IT HAS
SURVIVED ALONG OR SOUTH OF THE SOUTHWEST LOUISIANA COAST. ALL
INDICATIONS ARE THAT THE SYSTEM WILL REMAIN ASYMMETRICAL WITH THE
STRONG NORTHERLY SHEAR PUSHING ANY HEAVY PRECIP TO THE SOUTH SIDE OF
THE STORM ALONG WITH THE STRONGER WINDS. THERE MAY BE A POTENTIAL
FOR SOME STRONGER SHOWERS WITH HIGH RAIN RATES RIGHT ALONG THE COAST
ON THURSDAY.
BERTHA IS EXPECTED TO DISSIPATE BY THE WEEKEND WITH THE UPPER LEVEL
RIDGE BECOMING THE MAIN WEATHER PLAYER THAT WILL BRING LIMITED RAIN
CHANCES AND HOT CONDITIONS.
07/RUA
AVIATION
(06Z TAFS)
ISSUED AT 1233 AM CDT WED JUL 22 2026
OVERNIGHT, STABLE CONDITIONS CAN BE EXPECTED WITH JUST SOME HIGH
LEVEL CLOUDS. CONVECTION FROM BERTHA SHOULD STAY SOUTHEAST OF THE
TERMINALS. MAINLY VFR EXCEPT FOR SOME PATCHY FOG OR HAZE FOR THE
KAEX TERMINAL WITH SOME POTENTIAL MVFR CONDITIONS AROUND SUNRISE OR
BETWEEN 21/09-13Z.
BATTLE AGAIN ON WEDNESDAY BETWEEN DRY AIR IN THE MID AND UPPER
LEVELS AND MOISTURE TRYING TO MOVE IN FROM TROPICAL STORM BERTHA.
RIGHT NOW IT LOOKS LIKE THE KLFT AND KARA TERMINALS WILL HAVE THE
BEST CHANCE OF SEEING SOME SHOWER ACTIVITY IN THE LATE AFTERNOON
ALONG WITH BREEZY NORTH WINDS.
07/RUA
MARINE
ISSUED AT 1233 AM CDT WED JUL 22 2026
WEAK HIGH PRESSURE OVER THE WESTERN GULF AND THE CIRCULATION AROUND
TROPICAL STORM BERTHA WILL BRING MODEST WEST WINDS TODAY. WINDS AND
SEAS ARE EXPECTED TO INCREASE TONIGHT AS BERTHA NEARS THE COASTAL
WATERS. MARINE CONDITIONS ON THURSDAY WILL DEPEND ON THE EVENTUAL
TRACK AND STRENGTH OF TROPICAL STORM BERTHA AS IT MOVES JUST INLAND
OR OVER THE NORTHWEST GULF. AT THIS TIME TROPICAL STORM WINDS ARE
POSSIBLE LATE WEDNESDAY NIGHT INTO THURSDAY EAST OF CAMERON. ALL
MARINE INTERESTS SHOULD CONTINUE TO MONITOR UPDATES ON TROPICAL
STORM BERTHA.
FIRE WEATHER
ISSUED AT 1233 AM CDT WED JUL 22 2026
HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS THE REGION TODAY.
AFTERNOON MINIMUM RH VALUES WILL BE IN THE 50 TO 60 PERCENT RANGE
AND WHEN COMBINED WITH AIR TEMPERATURES NEAR 100 THE HEAT INDEX IN
THE AFTERNOON WILL BE AROUND 115 DEGREES. TROPICAL STORM BERTHA WILL
APPROACH THE AREA LATE TONIGHT INTO THURSDAY. AT THE MOMENT THIS
SYSTEM IS EXPECTED TO BE ASYMMETRICAL WITH A MAJORITY OF THE HIGHER
WINDS AND RAIN AMOUNTS TO THE SOUTH OF THE TRACK OF THE CENTER,
WHICH IS EXPECTED TO BE RIGHT ALONG OR JUST OFF THE COAST.
LCH WATCHES/WARNINGS/ADVISORIES
LA...TROPICAL STORM WATCH FOR LAZ074-252>254.
EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM CDT THIS
EVENING FOR LAZ027>033-044-045-055-073-074-141>143-152>154-
241>243-252>254.
TX...EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM CDT THIS
EVENING FOR TXZ180-201-259>262-515-516-615-616.
GM...TROPICAL STORM WATCH FOR GMZ435-436-452-455-472-475.
PUBLIC/FIRE/MARINE...07
AVIATION...07
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