Area Forecast Discussion
Issued by NWS Lake Charles, LA
Issued by NWS Lake Charles, LA
466 FXUS64 KLCH 131056 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 556 AM CDT Thu Aug 13 2026 ...New AVIATION... .KEY MESSAGES... - An upper level ridge will strengthen over the region through the weekend into early next week and be the main weather player. - Air temperatures and heat index values will be increasing with the daily heat risk rising to moderate to major over the weekend and nearing extreme levels early next week. - With the lack of significant widespread rainfall, antecedent conditions will also become increasingly drier. && .DISCUSSION... (Today through Wednesday) Issued at 1225 AM CDT Thu Aug 13 2026 When viewing satellite imagery and model-analyzed 500 heights across the US, it`s easy to see the action is happening well away from the north Gulf region. To the west, upper trof extends down the spine of California, halted in place by a dense dome of high pressure extending into the MO Bootheel from the south / Gulf region. Over the last 24 hours, this pressure dome has increased in height, with this height to persist. Thus, the hot and (mostly) dry conditions today will be further enhanced today with a more- widespread coverage of highs in the upper 90s. Outside of influence of the upper ridge, there is the sfc high centered over the northeast Gulf which will extend westward moreso Thursday. Off the sfc, prevailing southwesterlies will mix very dry Texas airmass into the region, driving down PWATs and RH values Thursday. Even with the elevating heat, the decrease in moisture will help keep daytime heat indices in check and just below criteria. No Heat Advisory for Thursday. Late Thursday, an upper wave moving into Mexico will send a plume of tropical moisture up the Texas coastline overnight into Friday morning. This slug of moisture will wash into the Golden Triangle region to southeast LA in the pre-dawn hours Friday, extending north and east throughout the day. Isolated showers with perhaps an isolated thunderstorm will accompany this moisture plume on its travels. However, don`t anticipate a lovely rainy morning to break this heat dome! The already-strong upper ridge will increase in strength rapidly on Friday with a very notable rise in heights expected over the entire SEUS in a short time. PWATs are forecast to jump back to ~2.05 inches on Friday from the fcst low of ~1.35 inches Thursday. (For context, this jump of PWAT will take us from roughly the 12th percentile to the 75th percentile. That`s a very impressive airmass overhaul from one day to the next.) Typically this would bring a day of at least cloud cover and showery convection, but the rapid increase pressure will halt any inland penetration of rainfall Friday. Southeast Texas and extreme southwest Louisiana could benefit from a few extra clouds compared to everywhere else which may keep their temps slightly lower. But elsewhere, another increase in high temps can be expected. Highs in the upper 90s to around 100 will be very likely, and the influx of humidity may bring a need for Heat Advisories to end the work week. Saturday and beyond, the upper ridge looms and controls. Hot continental air mixes back into the column, with the "opening a preheated oven in your face" experience in full effect. All rain chances shut off and little to no cloud cover will help deflect the searing sun. Heat Indices each day should be mixed down into the 103 to 108 range each day; borderline for Heat Advisory but well within a heat wave which will be impactful to those not accustomed to these temps. 11/Calhoun && .AVIATION... (12Z TAFS) Issued at 555 AM CDT Thu Aug 13 2026 TAFs will be VFR this period with winds from the south. && .MARINE... Issued at 1225 AM CDT Thu Aug 13 2026 Surface high pressure ridge extending west from the northeast Gulf will keep a southerly fetch in place over the period. Winds will prevail below 10 knots, which also keeps seas low. A slug of tropical moisture moving up the Texas coastline late Thursday night into early Friday morning could bring scattered showers to western waters prior to sunrise Friday. High pressure over the region will strengthen rapidly on Friday, dissipating any lingering rainfall quickly into the morning. No rain chances anticipated through the weekend. && .FIRE WEATHER... Issued at 1225 AM CDT Thu Aug 13 2026 Hot, dry continental air off of Texas will move into the region, further knocking down daytime RH values on Thursday. A range of 40 to 50 percent can be anticipated with a prevailing southerly wind at the surface. Early Friday, a slug of tropical moisture will move into southeast Texas, southwest Louisiana from the south. Upper high pressure covering the entire southeast US is also expected to rapidly strengthen on Friday. Thus, expect an increase in daytime RH values slightly, but no rainfall or reprieve is anticipated. Very hot and unseasonably dry conditions are then expected from Saturday and beyond as the high pressure dome locks in place. && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ PUBLIC/FIRE/MARINE...11 AVIATION...14