FXUS64 KLCH 200607 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 107 AM CDT Wed May 20 2026 ...New DISCUSSION, AVIATION, MARINE, FIRE WEATHER... .KEY MESSAGES... - An unsettled pattern will be in place into the Memorial Day Holiday weekend as the southern jet stream brings a series of upper level disturbances to work with a very moist air mass. - The showers and thunderstorms that develop will have the potential to produce high rain rates and there is a risk of heavy rainfall and a risk for flooding into early next week. - All interests in flood prone low-lying areas or flood prone urban poor drainage area, along with those along stream and river basins should keep aware of the latest flood risk forecasts. - Temperatures will remain on the warm and humid side through the period. && .DISCUSSION... (Today through Tuesday) Issued at 100 AM CDT Wed May 20 2026 A complex of showers and thunderstorms will continue to move eastward across the forecast area into Acadiana and then gradually weaken by daybreak. Showers and occasional thunderstorms will continue behind the line before also gradually decreasing by morning. Some high rain fall rates, brief gusty winds, and frequent lightning will be the main concerns for the next few hours. The ongoing convection is expected to work over the atmosphere enough that it is expected to take a while on Wednesday to activity going again. With a very moist air mass and daytime heating, showers and storms are expected to develop by early to mid afternoon with the higher chances where the old boundary will be located across the forecast area. No real changes are seen in the ongoing forecast for the remainder of the week and into the holiday weekend, as generally an upper level trough will be found across the Western US into the Rockies with an upper level ridge over the eastern Gulf and northwest Caribbean. In between the sub-tropical jet will stream over the forecast area bringing mid and upper level moisture from the Tropical Pacific to go along with the low level Gulf moisture from the southerly flow around a surface high east of the region. This will allow the forecast area to see a highly anomalous moist air mass with daily PWAT values over the 90th percentile of 1.79 inches and near the Max Moving Average of 2+ inches. Meanwhile, mean layer relative humidity between 100H-50H will be over 80 percent. Warm cloud precipitation processes will also be noted as the warm cloud layer is projected to be from 11k to 15k feet, noting an almost tropical like air mass. So, we do know that there will be several days of high rain chances with possible locally heavy rainfall and a flood risk. WPC has outlined a majority of the forecast area in a Marginal (1 out of 4) to Slight (2 out of 4) Risk or at least a 5 to 25 percent chance of excessive rainfall leading to flooding for each day through Sunday, and extended WPC hazards keep a risk of heavy rainfall with flooding possible all the way through May 27. What is of a lower confidence is the timing each day of when the precipitation will be the most widespread and at its heaviest. It will not rain all the time, but the timing of each upper level disturbance and if it comes during max daytime heating, will be the story of when the rain chances will be the highest. So each day will be more fine tuned the closer in time we get to each day. Also, as the antecedent conditions become more moist with wet grounds, and hydro flow begin to increase, the risk for flooding may increase in time. Otherwise, temperatures will remain rather warm with humid conditions through the period. 07/Rua && .AVIATION... (06Z TAFS) Issued at 1233 AM CDT Wed May 20 2026 A complex of showers and thunderstorms willcontinue to move east across the forecast area during the overnight. The strongest activity is expected to be at the KLFT and KARA terminals with some low visibility due to the heavy rain along with gusty winds. As the intensity of the shower activity decreases, expect mainly MVFR ceilings and visibilities to develop through 20/14z. Daytime heating will bring about another chance for showers and thunderstorms after 20/19z. 07/Rua && .MARINE... Issued at 100 AM CDT Wed May 20 2026 Surface high pressure across the northern Gulf with a stalled frontal boundary to the north. This will allow for a persistent light to moderate southeast flow and light to modest seas through the week. Chances for showers and thunderstorms will also continue through the week and remain high into the weekend as a series of upper level disturbances produce several waves of precipitation. && .FIRE WEATHER... Issued at 100 AM CDT Wed May 20 2026 Expect modest southerly winds to continue through the next several days bringing in rich amounts of Gulf moisture. Afternoon Minimum RH values will be above 70 percent through the week into the weekend. High chances for daily showers and thunderstorms are also expected through the week into early next week as a stalled frontal boundary and a series of upper level disturbances provide waves of precipitation each day. Some locally heavy rainfall will be possible. The high minimum relative humidity values and expected wet antecedent conditions is expected to keep fire weather in check. && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ PUBLIC/FIRE/MARINE...07 AVIATION...07