Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
026 FXUS64 KLIX 301927 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 227 PM CDT Tue Sep 30 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .KEY MESSAGES... - Rain and storm chances slowly increase late this week with better chances this weekend. - Winds and seas will increase late this week and weekend leading to Small Craft Advisories expected. - Minor coastal flooding along east facing showers of southeast LA, including inside the tidal lakes, and Hancock, MS county expected Friday and into the weekend. && .SHORT TERM... (This evening through Wednesday night) Issued at 224 PM CDT Tue Sep 30 2025 In fear of sounding like a broken record it was another warm, dry, and quiet day. Moisture has slowly increased with RH vales generally remaining in the 40 to lower 50% range while highs still climbed into the upper 80s and lower 90s. There was an increase in cloud cover today compared to the last few but still didn`t see the amount of high clouds move in that looked like it could`ve been yesterday. As for the forecast for the next few days not much has changed in the previous thinking. The mid lvls will see quite a bit of changes over the next week and that begins in earnest tomorrow. Some of the key features that are controlling things continue to be our two hurricanes in the western Atlantic both moving to the northeast now, the broad mid lvl low over the sern CONUS trapped by the ridge over the Great Lakes and OH Valley/Midwest, and the s/w moving through the southern and central Plains. Imelda and Humberto will have no impact on the region but the interaction between Imelda and the broad mid lvl low over the sern CONUS will continue to have an impact on the forecast through Thursday. As mentioned yesterday with a slower track and development of Imelda it wasn`t able to move as close to the US coast and now has had far more interaction with Humberto allowing Humberto to basically carve out a path for Imelda to escape over the Atlantic. It also didn`t force the mid lvl low to take as much of a southwest jog towards the Lower MS Valley and instead will move more towards the north-central/northeast Gulf coast tomorrow and tomorrow night. At the same time the ridge over the Great Lakes and Midwest has not slid as far east and is even sliding back towards the Mid Ms Valley some. That is blocking the s/w over the central/southern Plains. Part of the s/w will go north and ride up over the ridge while some of it will surge east- southeast over the Lower MS Valley tonight and early tomorrow. This feature could have provided more than enough support to get some rain across the area the problem though is there is really no moisture available abv h7 and even the moisture that is in place is confined to around the h85-h7 layer as the LL and boundary layer are fairly dry as well. With that the area will likely remain rain free tomorrow and highs will climb into the upper 80s and lower 90s once again. Thursday things will continue to evolve. The Plains s/w will merge with the mid lvl low/trough over the northeastern Gulf coast and by Thursday night a broad closed mid lvl low is expected to develop. This feature will be a primary driver of the forecast for Friday and through much of the weekend but as for Thursday with it taking shape later Thursday and farther to the east there is a good chance that most of the area will remain rain free for another day. Rain chance will increase across coastal areas as we slowly see a boundary set up from coastal SELA east-southeast into the eastern Gulf and the FL peninsula. More on that boundary in the extended. As mentioned we will struggle to see much rain on thursday but one thing that could begin Thursday and will become a bigger impact over the next few days will be tides. Moderate to strong easterly winds will develop over the northern Gulf and this will begin to drive water into the LA coast but tides should remain below adv limits Thursday. /CAB/ && .LONG TERM... (Thursday through Monday night) Issued at 224 PM CDT Tue Sep 30 2025 As for the extended portion of the forecast, this gets a little more active with some minor impacts expected, and finally higher rain chances. The medium range models continue to be in fairly good agreement with the overall pattern over the much of the CONUS. This is the GFS, ECMWF, GEM, and their respective ensembles. However there are some differences in the sfc and LL features that may have some impacts Sunday. Overall confidence is high in some aspects of the forecast however confidence is low on rain potential and that is mainly amounts and coverage. With most of the guidance in fairly good agreement but still low confidence on areal coverage of rainfall the NBM this period looks pretty good and will make no adjustments from it. Synoptically the models have remained mostly consistent with a closed mid lvl low over the Gulf coast states by Friday and it retrograding west towards the northwestern Gulf coast and Lower MS Valley by Saturday. It sits over that general area for another 24 to 36 hours before slowly filling early next week. That said the location and depth of it will help some thing tighten up in the LL and at the sfc. As mentioned early there will be this quasi boundary/LL confluent area from south/near the SELA coast to the FL peninsula. A large and dominate area of high pressure over the Mid Atlantic/northeast CONUS will wedge all the way down towards the Gulf coast while broad low pressure is in place over the southern and southwestern Gulf. This will already setup a strengthening easterly wind across the northern Gulf but with the added lift these winds will continue to increase Friday and into Saturday. This will transport moisture towards the area this weekend but also slightly enhance the frontal like aspect across the northern Gulf. The increase in winds along with the duration of the strong easterly winds will begin to lead to some minor coastal flooding impacts across east facing shores of SELA, the tidal lakes, and Hancock county. Coastal Flood Adv will likely be needed Friday and through the weekend for tides 1-2 ft abv normally dry land along the immediate coast. As for rain potential Friday it looks like rain again may be confined mostly coastal areas. The mostly easterly winds Friday won`t help to transport deeper moisture inland Friday but Saturday and Sunday moisture may start to penetrate deeper inland. This may be very dependent on any type of wave developing along that boundary/confluent zone. If we start to get some buckle along that area with an inverted trough beginning to develop (maybe even a weak sfc low) that will have a much greater chance of bringing deeper moisture and rain inland. That could also lead to some increase in the coastal flood potential. /CAB/ && .AVIATION... (18Z TAFS) Issued at 224 PM CDT Tue Sep 30 2025 VFR conditions continue for all terminals and will do so through the fcst. Winds also continue to remain on the light side. /CAB/ && .MARINE... Issued at 224 PM CDT Tue Sep 30 2025 Offshore flow will continue for another 24hrs before winds veer around out of the east-northeast and then east by Thursday. Winds will also remain light for another 24hrs then slowly begin to increase. With a large dominate area of high pressure over the northeast and Mid Atlantic and broad weak low pressure over the southern and southwestern Gulf a prolonged and strengthening easterly wind will develop over the north-central and northeastern Gulf starting Wednesday night and persisting into the weekend. Moderate winds could develop as early as tomorrow night requiring SCS headlines for portions of the coastal waters while SCY headlines may be needed for the waters east of the MS Delta Thursday. Winds will likely be a solid 20 kts Thursday night and maybe approaching 25 kts. Seas will be increasing as well with the outer waters south and east of the MS Delta increasing to 6-8` and given the prolonged strong easterly flow may even be more like 7-9/10` in the outer waters Friday and Saturday. Storms will also start to increase in coverage over the coastal waters Thursday and persist through the weekend. As we get deeper into the weekend there is some uncertainty as a weak area of low pressure may try to slowly take shape along an boundary/area of low lvl convergence draped across the central/north- central Gulf. Not only would this have an impact on wind strength and direction but will also increase the showers and thunderstorms /CAB/ && .PRELIMINARY POINT TEMPS/POPS... MCB 67 90 67 88 / 0 10 10 10 BTR 67 92 69 90 / 0 10 0 20 ASD 67 89 66 86 / 0 10 10 20 MSY 74 91 74 88 / 0 10 10 30 GPT 70 87 69 86 / 0 20 10 20 PQL 67 88 64 87 / 0 20 10 20 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...CAB LONG TERM....CAB AVIATION...CAB MARINE...CAB