654
FXUS64 KLCH 212329
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
629 PM CDT TUE JUL 21 2026
..NEW AVIATION
KEY MESSAGES
- TROPICAL STORM BERTHA IS EXPECTED TO MOVE WEST NEAR THE COAST OF
THE NORTHERN GULF THROUGH THE END OF THE WEEK. THIS SYSTEM IS
EXPECTED TO BE ASYMMETRICAL WITH A MAJORITY OF THE IMPACTS SOUTH
OF THE CENTER.
- A HEAT ADVISORY IS IN EFFECT FOR THE REMAINDER OF THIS
AFTERNOON. THE COMBINATION OF SINKING AIR ALOFT AS AN UPPER
LEVEL RIDGE FROM THE ROCKIES BUILDS IN AND THE OUTFLOW FROM
TROPICAL STORM BERTHA WILL DEVELOP OPPRESSIVE HEAT INTO
WEDNESDAY. AN EXTREME HEAT WARNING HAS BEEN ISSUED AREAWIDE
WEDNESDAY. MAX AFTERNOON HEAT INDEX IS EXPECTED TO RANGE FROM
113 TO 117 DEGREES.
- OVER THE WEEKEND INTO EARLY NEXT WEEK, THE UPPER LEVEL RIDGE
WILL REMAIN CONTROL WITH LIMITED RAIN CHANCES AND HOT
CONDITIONS.
DISCUSSION
(THIS EVENING THROUGH NEXT MONDAY)
ISSUED AT 144 PM CDT TUE JUL 21 2026
THE SHORT TERM PATTERN IS RELATIVELY ACTIVE WITH TROPICAL STORM
BERTHA TRACKING NORTHWEST BELOW THE FLORIDA PANHANDLE AND A STRONG
SUBTROPICAL RIDGE RESTING OVER OVER THE SOUTHERN PLAINS. 1:00PM CDT
SATELLITE ANALYSIS ILLUSTRATES CONVECTION OVER BERTHA IS ASYMMETRICAL
WITH THE WIND FIELD. THE SYSTEM HAS TWO STRONG SOUTHERN QUADRANTS
WITH DEEP CONVECTION, HOWEVER, THE NORTHERN HEMISPHERE OF THE STORM
REMAINS OPEN AND CONTINUES TO PULL IN DRY AIR. THIS EFFECT IS AN
IMPORTANT AND HELPFUL INHIBITING FACTOR KEEPING THE SYSTEM FROM
RAPIDLY INTENSIFYING. THAT SAID, TROPICAL STORM WATCHES HAVE BEEN
POSTED ALONG AND BELOW THE ATCHAFALAYA BASIN.
COMBINATION OF COMPRESSIONAL WARMING FROM THE SUBTROPICAL RIDGE TO
THE NORTHWEST AND THE APPROACHING TROPICAL STORM BERTHA WILL RESULT
IN HOT TEMPERATURES WEDNESDAY. THAT IN ADDITION TO HIGH DEWPOINTS,
HAVE WARRANTED AN EXTREME HEAT WARNING ACROSS THE FORECAST AREA.
HEAT INDICES ARE FORECAST TO CLIMB UP TO 113-117F. EXTRA CARE
SHOULD BE TAKEN FOR PEOPLE, PLANTS, AND PETS DURING THESE
DANGEROUSLY HOT CONDITIONS.
BASIS THE LATEST ANALYSIS FROM OUR COLLEAGUES AT THE NATIONAL
HURRICANE CENTER, BERTHA IS EXPECTED TO TAKE A DUE WEST TRACK ALONG
OR JUST SOUTH OF THE LOUISIANA COAST LINE. AS THE SYSTEM APPROACHES
THE MISSISSIPPI DELTA, LAND INTERACTION WILL BEGIN TO DISRUPT THE
LOW LEVEL FLOW. ANY FURTHER NORTHWARD DEVIATION IN TRACK WOULD
FURTHER INCREASE THIS EFFECT. ADDITIONALLY, THE SYSTEM WILL PULL
MORE DRY AIR INTO THE CENTER OF CIRCULATION DECREASING CONVECTION IN
THIS REGION.
BERTHA STILL REQUIRES CLOSE MONITORING REGARDLESS OF STRENGTH. THE
SYSTEM WILL HAVE CLOSE PROXIMITY TO THE COAST. EVEN DECAYING
TROPICAL SYSTEMS CAN DEVELOP SHORT TERM HAZARDS SUCH AS EXCESSIVE
RAINFALL AS THEY EXPAND AND INTERACT WITH THE LOCAL ENVIRONMENT.
WHILE THE FLOODING RAINFALL THREAT IS FAVORED TOWARD THE COAST,
SQUALLS OF RAIN BANDS COULD DEVELOP INLAND THURSDAY. AT THIS TIME,
THERE ARE NO SEVERE WIND, HAIL, OR TORNADO PROBS. HOWEVER, PLEASE
CONTINUE TO MONITOR FORECASTS GOING FORWARD THROUGH DISSIPATION.
BERTHA IS EXPECTED TO WEAKEN INTO A TROPICAL DEPRESSION QUICKLY
PASSING OFFSHORE CAMERON PARISH THURSDAY AFTERNOON. FORECAST
CONFIDENCE REMAINS HIGH THAT HIGH WIND SHEAR AND DRY AIR WILL IMPEDE
THE SYSTEMS ABILITY TO MAINTAIN AND SIGNIFICANT WEAKENING IS
EXPECTED AS IT APPROACHES THE SOUTHEAST TEXAS COAST.
ONCE BERTHA, OR HER REMNANTS, HAVE CLEARED THE AREA FRIDAY
AFTERNOON, TEMPERATURES WILL RANGE IN THE MID 90S WITH DRIER WEATHER
EXPECTED THROUGH NEXT MONDAY.
KOWALSKI / 30
AVIATION
(00Z TAFS)
ISSUED AT 626 PM CDT TUE JUL 21 2026
THUNDERSTORMS WILL REMAIN IN VICINITY OF KAEX FOR THE NEXT 2-3
HOURS. A BRIEF PERIOD OF LOWER VIS AND CEILINGS MAY OCCUR.
ADDITIONAL CONVECTION MAY OCCUR NEAR KLFT OR KARA LATE TONIGHT. THE
REMAINDER OF THE REGION WILL REMAIN VFR THROUGH MID DAY
WEDNESDAY, HOWEVER CONVECTION WILL MOVE IN LATE IN THE PERIOD
AROUND THE CIRCULATION OF BERTHA. NW WINDS WILL BECOME MORE
NORTHERLY DURING WEDNESDAY.
AVIATION
(18Z TAFS)
ISSUED AT 144 PM CDT TUE JUL 21 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE EVENING HOURS
ACROSS ALL TERMINALS WITH EXCEPTION OF LFT AND ARA. A REGION OF VCTS
MAY ALLOW TS THROUGH MID AFTERNOON AND REDUCE CONDITIONS ACROSS
ACADIANA. TONIGHT CONVECTION IS EXPECTED TO BE MOSTLY NULL WITH
INCREASING WEST WINDS INTO WEDNESDAY. HOT CONDITIONS ARE EXPECTED
WHICH RESULT IN STRONGER THERMALS NEAR THE BOUNDARY LAYER / LCL.
14
MARINE
ISSUED AT 144 PM CDT TUE JUL 21 2026
HIGH PRESSURE OVER THE NORTHWEST GULF AND THE CIRCULATION AROUND
TROPICAL STORM BERTHA WILL BRING MODEST WEST NORTHWEST WINDS INTO
WEDNESDAY. AT THIS TIME TROPICAL STORM WATCHES HAVE BEEN POSTED FOR
VERMILION BAY AND OFFSHORE WATERS TO THE SOUTH, AS FAR WEST AS
VERMILION / CAMERON PARISH LINE. MARINE CONDITIONS FOR WEDNESDAY
NIGHT THROUGH FRIDAY WILL DEPEND ON THE EVENTUAL TRACK AND STRENGTH
OF TROPICAL STORM BERTHA AS IT MOVES JUST INLAND OR OVER THE
NORTHWEST GULF. ALL MARINE INTERESTS SHOULD CONTINUE TO MONITOR
UPDATES ON TROPICAL STORM BERTHA.
FIRE WEATHER
ISSUED AT 144 PM CDT TUE JUL 21 2026
HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS THE REGION THROUGH
MIDWEEK. AFTERNOON MINIMUM RH VALUES WILL BE IN THE 45 TO 60 PERCENT
RANGE. WITH TEMPERATURES NEARING 100, AN EXTREME HEAT WARNING IS IN
PLACE OVER THE ENTIRE FORECAST AREA. PLEASE CONSIDER THESE
CONDITIONS FOR THE SAFETY OF THOSE OUT IN THE FIELD. TROPICAL STORM
BERTHA WILL APPROACH THE AREA ON 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.
LCH WATCHES/WARNINGS/ADVISORIES
LA...TROPICAL STORM WATCH FOR LAZ074-252>254.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LAZ027>033-044-045-
055-073-074-141>143-152>154-241>243-252>254.
EXTREME HEAT WARNING FROM 10 AM TO 8 PM CDT WEDNESDAY FOR
LAZ027>033-044-045-055-073-074-141>143-152>154-241>243-
252>254.
TX...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR TXZ180-201-259>262-
515-516-615-616.
EXTREME HEAT WARNING FROM 10 AM TO 8 PM CDT WEDNESDAY FOR TXZ180-
201-259>262-515-516-615-616.
GM...TROPICAL STORM WATCH FOR GMZ435-436-452-455-472-475.
PUBLIC/FIRE/MARINE...30
AVIATION...05
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