Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
538 FXUS64 KLIX 081043 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 543 AM CDT Tue Sep 8 2026 ...New AVIATION... .KEY MESSAGES... Updated at 542 AM CDT Tue Sep 8 2026 - Scattered showers and storms are forecast throughout the forecast period. The overall severe weather threat will be low, but one or two storms could become strong to severe each day. - Primary threats with storms will be strong wind gusts, frequent lightning and periods of heavy rain leading to localized flash flooding. - Above normal temperatures expected for most of the 7-Day forecast period. Afternoon heat indices will generally range from 100 to 108 degrees. && .SHORT TERM... (Now through Friday) Issued at 1221 AM CDT Tue Sep 8 2026 A very weak inverted trough axis will slip through the area today and tomorrow, but enough dry air will remain in place aloft to keep PWATS in the 1.75 to 2 inch range. These values are around the mean to 75th percentile for this of year. There will be a north to south gradient of the PWAT with lower values to the north where the influence of the ridge centered over the Deep South will be greatest. The end result will be lower overall PoP of 20 to 40 percent for areas along and north of I-10/12 and higher PoP of 40 to 60 percent south of I-10 where both the deeper moisture and influence of the weak inverted trough is greatest. A review of model soundings shows a low potential for severe storms to develop today and tomorrow with the highest probability north of I-12 where some dry air entrainment into any deeper updrafts has the best chance of occurring. Still, even the deepest updrafts and strongest storms should see winds stay below severe limits today and tomorrow at 40 to 50 mph. Storm motion will be fairly progressive at 10 to 15 mph each day, so the flood threat will be lower. Rainfall rates of 2 to 3 inches per hour will occur, but the duration of the rainfall should limit rainfall to 1 to 2 inches in most areas today and tomorrow. At most, a few more flood prone spots could see some minor ponding of water as the storms move through. Temperatures will be near average for early September in the upper 80s and lower 90s and heat index values will peak below advisory levels both days. As we move into Thursday and Friday, conditions will turn more favorable for increased convective development. The ridge over the Deep South will weaken and shift to the east as a northern stream shortwave trough axis digs into the central and southern Plains. The inverted trough will feel the influence of this shifting pattern and slide back over the area. PWATS will surge to around 2 to 2.1 inches, or between the 75th and 90th percentile, for this time of year, as deeper tropical moisture feeds into the mid and upper levels of the atmosphere. Although overall instability will decrease with SBCAPE falling to around 1000 J/KG, increasing vorticity and forcing aloft will be sufficient to support extensive updraft development as temperatures climb into the 80s each day. Shower and thunderstorm activity will fire up offshore each day and quickly spread inland as the seabreeze forms, and PoP of 60 to 80 percent is in the forecast to reflect this more favored rainy pattern. Fortunately, conditions do not look favorable for strong winds to accompany the storms, so the primary concern will be the slower storm motions and continued high rainfall rates of 2 to 3 inches per hour. Localized flooding, especially in low lying and poorly drained areas, has a higher probability of occurring in the afternoon hours on Thursday and Friday. This flooding will mainly be confined to street and underpass flooding that could close some roads. Temperatures will be near average and heat index values will be closer to advisory levels due to higher dewpoints. However, the rainfall will help limit the heat threat as widespread convective activity cools temperatures in the afternoon hours. Peak heating will most likely occur in the late morning and lunch hours before the storms develop. && .LONG TERM... (Friday night through Monday) Issued at 1221 AM CDT Tue Sep 8 2026 .LONG TERM...The extended portion of the forecast will begin much like the short tern forecast with decent daily rain chances but the pattern begins to shift towards a warmer and drier set up as we move into the end of the weekend and the beginning of the next work week. There are some minor disagreements in the medium range operational models however, the differences are only some slight timing issues and that is 5 to 6 days away so not bad honestly. In addition the ensemble means are in agreement and overall they all agree we should see the rain potential begin to tick down by Sunday and especially next week as the ridge takes back over. NBM still looks to be a little overzealous with the PoPs Sunday and next week but it is atleast lower by 10-20% compared to Saturday. since confidence is not high enough to drop PoPs a good bit from where the NBM is we will just leave the PoPs where they are at. For the first half of the weekend Friday night and through Saturday we will still be heavily influenced by the weakness aloft. Moisture will still be highly abundant with PWs around 1.8 to 2.1". With moisture readily available and the lack of suppression aloft, showers and thunderstorms will continue to impact the region being driven diurnally. Isolated convection will likely persist into the early evening hours inland before transitioning to the marine areas overnight. Once we begin to heat up Saturday we will likely start to see convection develop along the sea/lake breeze and then outflow boundaries will dictate. Heading into Sunday there is a lot of uncertainty with respect to coverage. We will still see storms develop but will it be more numerous impacting most of the area or will it start to take a step back to more scattered. This will be highly dependent on how fast the ridge builds back over the area from the west and that is where the slight timing differences are coming into play. If the ridge builds in faster look for rain coverage to be much lower than Saturday however if the ridge builds in slower then we may only see a slight decrease in coverage. By Monday it looks like the ridge will be in place and we will most likely see isolated to widely scattered storms during the afternoon. && .AVIATION... (12Z TAFS) Issued at 542 AM CDT Tue Sep 8 2026 Thunderstorms will be primary concern today, mainly between 17z and 23z. PROB30 wording is in place at all of the terminals over this period of time for brief convective impacts lasting 30 to 60 minutes at most. Lightning, gusty winds of 20 to 30 mph, and reduced visibilties of MVFR and even IFR range will accompany these storms. Outside of the convective concerns, VFR conditions will prevail at all of the terminals today. && .MARINE... Issued at 1221 AM CDT Tue Sep 8 2026 A stronger easterly wind of 15 to 20 knots will develop over the waters east of the Mississippi River Tuesday and Wednesday as a weak tropical wave slides through the Gulf. These higher winds will push wave heights to 3 to 4 feet over the eastern waters and create choppy seas. As the wave slides to the west on Thursday and Friday, high pressure will build back over the waters. Winds will turn southerly and fall back to 5 to 10 knots as the high over the eastern Gulf expands to the west. Seas will also fall to 1 to 2 feet as the winds decrease. && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...PG LONG TERM....CAB AVIATION...PG MARINE...PG