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847 FXUS64 KLIX 120605AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA105 AM CDT Sat Sep 12 2026...New SHORT TERM, LONG TERM, AVIATION, MARINE....KEY MESSAGES... Updated at 1238 AM CDT Sat Sep 12 2026- An elevated risk for localized heavy rainfall leading to street flooding and overflowing of poor drainage will continue today.- Lower rain chances and warmer temps return next week.&&.SHORT TERM...(Now through Tuesday)Issued at 1238 AM CDT Sat Sep 12 2026A shortwave trough axis moving trough the region will continue tobring increased rain chances to the area today. This trough willinteract with a very moist environment as noted by PWATS of 2 to 2.2 inches which are in excess of the 75th percentile for this time of year. As temperatures warm into the 80s, updraft development will begin in the mid- morning hours and scattered to numerous showers and storms will start to fire up by the late morning hours. These showers and storms will continue to fire up through the mid to late afternoon hours before beginning dissipatein the evening hours with the loss of daytime heating. Storm motion will remain around 10 mph and rainfall rates of 2 to 3 inches per hour can be expected with the strongest storms. As a result, another day of localized flooding concerns, especially forlow lying and poorly drained urban areas, will be in play. The region remains in a level 1 out of 5, marginal, risk of flooding for today. The trough axis will begin to pull east of the area tomorrow and abroad upper level ridge over Texas will start to expand eastward.As the influence of the ridge increases, the mid and upper levelsof the atmosphere will begin to both warm and dry in response toincreasing subsidence on Sunday and Monday. This will allow PWATSto fall to between 1.8 and 2 inches. These values are still elevated for this of year at between the median and 75th percentile, but the increasing ridging aloft will help to somewhatlimit updraft development. Convective activity will struggle to maintain itself until temperatures warm into the lower 90s and theweak mid- level capping inversion is overcome. Overall, shower and storm coverage will be lower and will be more confined to the sea breeze and lake breeze boundaries where low level forcing is maximized. PoP will be closer to average in the 30 to 50 percent range. Another concern will the threat of stronger wind gusts withthe most intense storms that form. Drier air will easily entrain in the tallest updrafts and this could lead to winds of 40 to 50 mph with these more intense storms. An isolated severe wind gust of 60 mph cannot be ruled out for Sunday and Monday. This is supported by DCAPE values of around 1100 J/KG and favorable model sounding profiles exhibiting very steep lapse rates below 3km in excess of 8.0C/km. By Tuesday, continued drying and warming aloft as the ridgebecomes centered over the Tennessee Valley will push PWATS down toaround the median values for this time of year. Convection willfire up later in the day, more toward the mid to late afternoon,when the convective temperatures in the low to mid 90s arereached. The end result will be more isolated to widely scatteredshowers and storms and PoP of 20 to 40 percent. Once again, stormswill fire up first along the sea breeze and lake breezeboundaries and then fire up along outflow from the previousconvection as those first storms collapse shortly after forming.Although the severe threat will be lower on Tuesday, one or twostorms could turn strong enough to pull in some drier air aloftand produce damaging wind gusts. &&.LONG TERM...(Tuesday night through Friday)Issued at 1238 AM CDT Sat Sep 12 2026By Tuesday night, upper level ridging is expected to be centered (598dm) near Chattanooga, Tennessee. Meanwhile, an upper trough that moves off the Mid-Atlantic coast Monday night and Tuesday is expected to close off a low off the coast of the Carolinas Wednesday and head southwestward around the upper ridge, crossing Florida and entering the eastern Gulf Thursday night into Friday. There's actually pretty decent agreement on the mid level feature between the GFS and ECMWF operational runs from the daytime hours Friday, at least through the end of the workweek next week. At this time, neither of the medium range models develops a surface low over the Gulf with this mid level feature. The drying of the airmass that is anticipated from the ridging on Sunday and Monday actually continues through most of the workweek, with precipitable water values even on Friday forecast to remain between the 50th and 75th percentiles in most of the area (1.5 to 1.8 inches).If the moisture depicted in the forecast soundings is in the ballpark, we may not see a lot of thunderstorms during the workweek. That would also mean the hot weather continues for most of next week with temperatures in the mid 90s looking reasonable. May not be enough humidity to justify heat advisories though.Beyond next Friday, the global operational models fall out of agreement with each other. The ECMWF continues to take the mid level system westward to the Texas coast without a lot of impact. The 18z GFS brings it to about 90W before starting to drift it east next weekend. We'll worry about those differences when next weekend falls within the range of the forecast.&&.AVIATION...(06Z TAFS)Issued at 1238 AM CDT Sat Sep 12 2026A weak inversion has formed over southwest Mississippi thismorning in relation to light boundary layer winds and continuedhigh relative humidity. This has resulted in LIFR low stratus andfog development at MCB in the last hour. These conditions willpersist through around 13z before quickly mixing out astemperatures begin to warm and inversion lifts. Outside of MCB,prevailing VFR conditions are expected at the remaining terminalsthrough daybreak. After 16-17z, scattered showers and storms willbegin to develop and could impact any of the terminals. PROB30wording is in place from 17z to 23z at the majority of theterminals for thunderstorm impacts with gusty winds of 20 to 25knots, lightning, and brief reductions in visibility. &&.MARINE...Issued at 1238 AM CDT Sat Sep 12 2026Winds will turn more south-southwesterly but with the Bermuda ridge centered well east of the area, wind speeds should be light at 10 knots or less today. The high will become more centered over the north-central Gulf Sunday into next week. This will cause winds to turn more south-southeasterly and even light/variable at times. Seas will generally remain in the 2 feet or less range. Additionally, thunderstorm activity will develop each day, peaking in the early to mid-morning hours, and these storms will produce higher wind gusts, waterspouts, and lightning concerns.&&.LIX WATCHES/WARNINGS/ADVISORIES...LA...None.GM...None.MS...None.GM...None.&&$$SHORT TERM...PGLONG TERM....RWAVIATION...PGMARINE...PG
