Area Forecast Discussion
Issued by NWS Lake Charles, LA
Issued by NWS Lake Charles, LA
623 FXUS64 KLCH 200530 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 1230 AM CDT Wed Aug 20 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, FIRE WEATHER... .KEY MESSAGES... - A weak upper level ridge aloft and northerly flow will bring about hot and humid conditions today with late in the afternoon thunderstorms which may bring locally heavy rainfall and gusty winds. - A trough will move into the forecast area on Thursday and linger into Friday bringing a decent chance for thunderstorms. With the expected high moisture content of the atmosphere heavy rainfall will be possible. - A building high pressure system over the Mountain West is expected to bring a dry northwest flow into the forecast area over the weekend with lower rain chances and less humid conditions. && .SHORT TERM... (Today through Friday night) Issued at 1226 AM CDT Wed Aug 20 2025 Watching some convection moving down from northeast Louisiana and northwest Mississippi toward central Louisiana. Guidance shows activity weakening before reaching the forecast area, and will go with this scenario as airmass over the forecast area has relatively stabilized. Again it is likely any nocturnal activity that forms tonight will be with an enhanced land breeze offshore and activity will stay offshore. For Today some weak upper level ridging is expected to extend into the forecast area from the ridge centered over the Four Corners, which will allow for northerly flow to be in place. Meanwhile, a surface trough will be noted north of the region. Convection is expected to develop late in the day ahead of the surface trough with northerly flow pushing it south into the forecast area. Decent Gulf moisture will be trapped below the ridge and ahead of the trough with PWAT expected above 2 inches and dew points in the mid 70s. Therefore, a moist and unstable air mass that will allow for convection to feed down into the forecast area. Also, seabreeze will likely try to push inland during the late afternoon, and any possible collisions between seabreeze and outflows from the north, likely after 4 pm, may set the stage for some localized robust storms with gusty winds, frequent lightning, and torrential downpours the main concern. Looking at the heat risk, air temperatures and dew points are expected to be similar as they were on Monday and Tuesday. Therefore, heat index readings in the afternoon before convection begins will range from 103F to 107F and thus will not have a heat advisory out. On Thursday, enhanced northerly flow between the upper level ridge over the Mountain West and the outer cyclonic flow from Erin off the Mid-Atlantic coast, will push a trough into the forecast area. High moisture content is expected to pool ahead and along the trough with PWAT around 2.25 inches and over the 90th percentile. Therefore, expect a good chance for showers and thunderstorms on Thursday and with the high moisture content, some torrential downpours will be possible. With the expected cloud cover and convection, heat risk is expected to be kept in check. This trough is expected to stall near the coast and linger into Friday with another day with a decent chance for showers and thunderstorms, especially over the southern zones with interactions between the surface boundary and sea breeze. Rua && .LONG TERM... (Saturday through Wednesday) Issued at 1228 AM CDT Wed Aug 20 2025 There continues to be indications that high pressure system over the Mountain West with strengthen and expand to the east with a general long wave trough along the eastern U.S. in the wake of Erin over the weekend. This is expected to strengthen the northerly flow over the forecast area that will bring in drier air. The result will be lower rain chances and less humid conditions for the weekend. Early next week the upper level trough is expected to continue along the U.S east coast. The upper level ridge over the Mountain West is expected to flatten and move south and be centered roughly across the southwest U.S. and Texas. This will allow for a rather benign west-northwest flow aloft over the region that should bring about rather climo temps and pops. The deterministic NBM is a little bit on the "lower" side on the spectrum of temperatures as we get into early next week and below the 25th percentile of the whisker plots. This is likely due to the influence of the GFS wanting to bring a surface front through the forecast area late Monday into Tuesday. Will not make any changes to the those periods at this time, however, it is probable that the support for a surface front moving through will lower as we get closer to weekend. Rua && .AVIATION... (06Z TAFS) Issued at 1229 AM CDT Wed Aug 20 2025 Fair conditions are noted at terminals currently and VFR levels are expected overnight. Although will be watching convection over northern Louisiana and northwest Mississippi to make sure it dissipates as expected before reaching central Louisiana. There is also an outside chance of some patchy fog toward sunrise that may briefly bring about visibility restrictions. On Wednesday, there will be a chance of showers and storms late in the afternoon as a trough starts to move down from the north and the seabreeze begins to become active. Therefore, will have VCTS after 20/21z. Away from the convection, VFR conditions with light winds are expected. Rua && .MARINE... Issued at 1229 AM CDT Wed Aug 20 2025 A weak pressure pattern will be found over the northwest Gulf through the end of the week. This will allow for light and variable winds along with low seas. A trough will move toward the coast from the north on Thursday stalling along the coast on Friday. This trough will help bring an increase in chances for showers and thunderstorms during any time of day through Friday. More typical scattered showers and thunderstorms, mainly late night and early morning, and again in the afternoon will be in the forecast over the weekend. && .FIRE WEATHER... Issued at 1229 AM CDT Wed Aug 20 2025 A hot and humid air mass will continue over the region on Wednesday with afternoon heat index values around 105 degrees and minimum relative humidity values over 50 percent. There will also be a chance for late afternoon thunderstorms. Moisture will increase further on Thursday as a trough moves into the region with minimum relative humidity values over 60 percent and the potential for widespread showers and thunderstorms, some of the storms may produce torrential downpours. && .PRELIMINARY POINT TEMPS/POPS... AEX 97 73 91 71 / 50 40 60 30 LCH 95 75 92 74 / 40 40 80 50 LFT 95 75 92 74 / 40 30 70 40 BPT 95 74 92 73 / 50 50 80 60 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ SHORT TERM...07 LONG TERM....07 AVIATION...07