Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
267 FXUS64 KLIX 281829 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 129 PM CDT Thu Aug 28 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .SHORT TERM... (This evening through Friday night) Issued at 128 PM CDT Thu Aug 28 2025 Current upper level analysis shows longwave trough over the eastern third/half of the country and ridge centered south of West Texas. A shortwave embedded within the trough will swing across the Great Lakes today. This will dig the base of trough farther south which slightly weakens the eastern edge of the ridge. Why this matters locally is this puts the CWA right on the path of northwest flow which opens the door per se, to convective development. Runs of various CAMs suggest potential for convection along and north of a line from St Francisville to Slidell. Best probs are in SW and Coastal MS. Model soundings show a not so surprising environment with ample instability (including DCAPE in the upper hundreds) and fairly light shear/helicity. So main threats will be gusty winds. Parameters don`t appear concerning but likely need to keep an eye on storms for severe potential through the late afternoon hours. Going into the evening however, surface cooling induced inversion in the low levels should limit gusty wind potential. However, coverage looks to persist into the evening and overnight hours as a backdoor frontal boundary associated with that trough to the east pushes into central LA and southern MS. MEFFER && .LONG TERM... (Saturday through Wednesday night) Issued at 128 PM CDT Thu Aug 28 2025 Global models consistently show the trough to the east broadening back west which in-tern weakens ridging aloft even more. With lingering frontal boundary, loss of subsidence, and PW`s sitting around 2.25"...widespread rain chances appear quite probable the entire weekend. Rain chance forecast calls for 50 to 80% and may be on the low side at times. Model sounding wind profile in the column suggests potential for back building setup. It`ll be crucial for storms to be monitored for this, especially over urban areas as precip processes should be quite efficient given expected PWs and mid level instability that`ll still be in place. Uncertainty increased Tuesday onward as models diverge on how much the trough to the east digs south. More digging will push drier airmass into the CWA. If that doesn`t happen, wetter pattern continues. MEFFER && .AVIATION... (18Z TAFS) Issued at 128 PM CDT Thu Aug 28 2025 VFR conditions generally still in place across the region this afternoon as CU field has become well established. Did add cloud decks to most terminals current line as it`s no longer SKC. The most likely appreciable impact at terminals this afternoon would come from developing showers and storms. Coverage will likely increase for terminals along and E to NE of a KBTR to KASD line. Therefore, the terminals in that area have been updated with the 18Z TAF issuance to account for storm potential this afternoon and evening. Not high chances but worthy of PROB30. MEFFER && .MARINE... Issued at 128 PM CDT Thu Aug 28 2025 The main marine concern during at least the first half of the forecast period will be the increasing threat for thunderstorms that could produce locally higher winds and seas. The ones today will more likely be in the evening to overnight hours. Gusty outflow winds upwards of gale force are the main threat. This threat for convection increases even more Friday into Saturday. Forecast confidence is a bit lower by late in the weekend, with an approaching cold front. The current wind forecast would indicate generally offshore flow by late Sunday afternoon for most or all of the waters as a backdoor cold front pushes in from the northeast. If the front makes it well into the Gulf early next week, that may justify Small Craft Exercise Caution headlines by Monday or Tuesday. MEFFER && .PRELIMINARY POINT TEMPS/POPS... MCB 70 82 70 85 / 60 80 70 70 BTR 74 88 72 88 / 40 70 50 80 ASD 71 86 70 85 / 40 60 50 80 MSY 77 90 77 88 / 20 50 40 80 GPT 71 85 71 84 / 40 60 50 80 PQL 69 85 70 85 / 30 50 50 80 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...ME LONG TERM....ME AVIATION...ME MARINE...ME