Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
374 FXUS64 KLIX 091120 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 520 AM CST Tue Dec 9 2025 ...New UPDATE, AVIATION... .KEY MESSAGES... Updated at 458 AM CST Tue Dec 9 2025 - Temperatures will begin moderating Tuesday night and Wednesday. Temperatures will be above normal Wednesday through at least Saturday. - Marine conditions improving on Tuesday. - Little or no rain expected through the weekend. && .UPDATE... Issued at 458 AM CST Tue Dec 9 2025 Performed an early morning update to align the forecast with observations/trends and latest model guidance through today. Main story is what is on GOES-16 night and fog products this morning illustrating a prominent low-level stratus deck over portions of the area, sustained at around 925mb. Above this layer, large-scale subsidence/compressional warming is evident from proximity satellite derived soundings associated with high pressure in the vicinity. This high and associated subsidence has continued to dry out/eat away at this moist layer form east to west overnight producing quite the complicated forecast in regards to temperatures. Areas that has seen clouds remain in place are noticeably on the very warm side of short-range blended guidance, while areas that have cleared out (more than several hours) are bottoming out quickly into the low 30`s, especially the drainage areas. Caught up on trends to highlight the MinT`s following this thinking keeping far western/southern areas warmer, and cooler for central/eastern areas with emphasis on the aforementioned drainage locations. Additionally, introduced patchy fog for the Pascagoula drainage basin following recent PQL trends and meteorological logic having maximized time underneath clear skies to aid in strong radiational cooling processes providing shallow/low-level patchy fog. Any fog should dissipate shortly after sunrise. Otherwise, high pressure should continue to win over this morning clearing out most areas, then, we warm up/mix out quickly under mostly sunny skies. We`ll keep an eye on the cloud line this morning and modify if it continues to impact temperatures greatly. But regardless, highs are aiming for around 60 for most areas which looks good in the suite of guidance this morning. KLG && .SHORT TERM... (Tonight through Wednesday night) Issued at 1125 PM CST Mon Dec 8 2025 A broad upper trough has reached the Atlantic Coast, with ridging over the Rockies and Pacific Coast. There is a southern stream shortwave that extended from Oklahoma to Arizona this evening. At the surface, the axis of a surface ridge extended from western New York to east Texas. A fairly thin layer of clouds around 925 mb, or about 3,000 feet, continued to sink southward across Mississippi into eastern and central Louisiana. These clouds are holding temperatures in the 40s this evening, with dew points in the upper 30s. Models have struggled with this shallow moist layer and the resulting cloud cover. It now appears that it could be mid to late morning Tuesday before the southern stream shortwave to our north and west suppresses the moisture around the 925 mb level far enough south to get rid of the clouds. In some respects, that would be a good thing, as it would lower the threat of freezing temperatures around sunrise. Unless we get quite a bit more clearing in the next few hours, overnight lows are at least one category too cold. Still could get some patchy frost in areas that see a break in the clouds for an hour or two. The axis of the surface ridge will shift off the Louisiana coast by Tuesday evening, with onshore winds returning. A strong upper trough will move through the Great Lakes and upper Ohio River Valley on Wednesday. This will force another frontal boundary through the area Wednesday afternoon and Wednesday night. There`s very little in the way of moisture with this front, with precipitable water values remaining near or below the 50th percentile climatologically. Highs Tuesday afternoon will likely top out near or just below 60, assuming the clouds depart as expected. Most of the area should see lows in the upper 30s to mid 40s Tuesday night, with highs 65 to 70 on Wednesday. Lows Wednesday night will be a couple degrees cooler than Wednesday morning...at worst. && .LONG TERM... (Thursday through Monday night) Issued at 1125 PM CST Mon Dec 8 2025 With the longwave trough axis well to our east for the end of the week, the upper flow will be west-northwesterly, which should keep the area mostly dry. It will also serve to shunt the coldest air well to the east of the area, continuing the trend we noted last night through at least the first half of the weekend. Another strong trough will move through the Great Lakes and upper Ohio River Valley over the weekend. This will push another cold front through the area, probably Saturday night or on Sunday. Looking at moisture distribution based on forecast soundings, it looks like it is going to be difficult to get any significant precipitation in our area through early next week. If it is going to happen, it`ll be with the weekend cold front. Maybe enough to redistribute dust on vehicles...quarter inch totals might be pushing things. Wednesday`s frontal passage will probably knock the Thursday high temperatures back a few degrees from Wednesday highs, but that would just put them around normal. Friday and Saturday highs look to be much above normal, with most areas getting into the lower 70s...at least...on Friday. If we get a good bit of sunshine on Saturday, mid 70s look reasonable. NBM highs are 3-6F cooler than the ECMWF and GFS 12z/08 operational guidance highs for Friday and Saturday, and wouldn`t be surprised to see the NBM numbers drift upward in the next 12 hours. Sunday`s highs will be dependent on timing of the frontal passage. Monday looks cooler, with below normal temperatures, for now. && .AVIATION... (12Z TAFS) Issued at 458 AM CST Tue Dec 9 2025 Main focus this morning will be monitoring a low-level stratus deck across the area, which continues to impact mainly far western and southern terminals providing OVC/BKN CIGs around 020 and remaining persistent. Meanwhile, clearing skies has introduced SKC for northern/eastern terminals. Will keep a close eye on the evolution of these CIGs this morning, as guidance supports these clouds to break up/dissipate with time. That`ll improve flight categories to mainly VFR prevailing through the rest of the forecast period. KLG && .MARINE... Issued at 1125 PM CST Mon Dec 8 2025 Will continue Small Craft Exercise Caution through 09z as winds and seas gradually subside. Conditions should be more favorable for marine operations, at least regarding winds and waves for Tuesday through Thursday. Once onshore flow develops at mid-week, that can be a signal for sea fog development during. At this time, the only window where dew points might support fog development would be perhaps Friday and Saturday. The next frontal passage will probably be over the weekend, and may need wind/wave headlines at that point. && .PRELIMINARY POINT TEMPS/POPS... MCB 57 38 66 38 / 0 0 0 0 BTR 59 40 69 41 / 0 0 0 0 ASD 58 39 68 40 / 0 0 0 0 MSY 58 44 70 48 / 0 0 0 0 GPT 56 41 67 42 / 0 0 0 0 PQL 58 37 67 39 / 0 0 0 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...RW LONG TERM....RW AVIATION...KLG MARINE...RW