Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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842 FXUS64 KLIX 260451 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1151 PM CDT Wed Sep 25 2024 ...New UPDATE, AVIATION... .UPDATE... Issued at 1128 PM CDT Wed Sep 25 2024 Quick update to keep a few showers and thunderstorms going into the overnight hours. A few of these have even been rather efficient rain producers. Even with instability waning we obviosuly have enough support aloft from the entrance region to the jet combining with the high moisture content of the atmosphere (PWs 1.91 on the 00z balloon) to help keep this convection going along with putting out some decent rain. /CAB/ && .SHORT TERM... (This evening through Thursday night) Issued at 402 PM CDT Wed Sep 25 2024 KEY MESSAGE: Hurricane Helene is entering the southern Gulf of Mexico and is expected to make landfall Thursday evening in the Panhandle of Florida. If you have interests whether it be property or friends or family in these areas, ensure they are prepared for a a Category 3 hurricane or even higher. Preparations for the storm should be rushed to completion and if you have been ordered to evacuate please do so. While all eyes are on Helene entering the GOMEX this afternoon, we have had a weak frontal passage that has sparked up some shower and thunderstorm activity. Anomalously cold mid-level temperatures in association with a deep, cut-off upper low over the lower MS Rivey valley are aiding in steeper lapse rates capable of stronger updrafts. Thus far, we have seen a few thunderstorms across Tangipahoa, Livingston, and St. Tammany Parishes take advantage of this more favorable environment and produced some hail and gusty winds. The storm over St. Tammany in particular produced a microburst which caused tree and roof damage near Mandeville and Covington. These showers and storms will gradually work their way to the southshore and coast, but predominantly will be isolated and short-lived in nature. These showers and storms will die out after sunset and we`ll see drier and cooler air gradually advect southward overnight allowing temperatures to cool slightly. /TJS/ && .LONG TERM... (Friday through Tuesday night) Issued at 402 PM CDT Wed Sep 25 2024 More appreciable advection of drier air from the north will start on Wednesday and continue through Thursday as the pressure gradient tightens with Hurricane Helene passing to the east of the area. Aside from the mid-upper level clouds from the outer edges and outflow layer from Helene, skies will be fair providing a stretch of downright beautiful fall days across our area into the weekend. Highs will be seasonably in the mid 80s with lows in the 60s inland to near 70F across the southshore. The long range pattern remains fairly dry and seasonable across the area into next week with lingering upper troughing keeping mid-level temps cooler and surface high pressure over the Plains keeping a steady stream of northerly winds. A reinforcement of this regime takes place on Tuesday as a shortwave trough kicks through and the post-frontal high brings another surge of continental dry air down into the area, right on cue for October (our climatologically driest month). Lastly, even with Hurricane Helene entering the Gulf today, we might hear whispers and see clickbait online of more Gulf tropical mischief on the horizon 7 to 10 days out. There is some truth to this as a tropical wave nearing the Lesser Antilles will need to be monitored as it moves into the western Caribbean next week which is what is being picked up on by the global model guidance over the past couple of days. However, it`s still too far out to know exactly where this disturbance will track or if it will even have the chance to develop yet. For now, just stay tuned to the latest tropical weather outlooks. /TJS/ && .AVIATION... (06Z TAFS) Issued at 1128 PM CDT Wed Sep 25 2024 Other than these pesky storms still impacting a few areas the only terminals that may still see impacts will be MSY and possibly HUM over the next few hours. After remaining conveciton moves out of the area VFR conditions are then expected. Drier air will infiltrate from the north allowing with breezy northerly winds across much of the area tomorrow. /CAB/ && .MARINE... Issued at 402 PM CDT Wed Sep 25 2024 Winds and seas will begin to build overnight tonight as the pressure gradient tightens with encroachment from Hurricane Helene. Offshore winds will intensify to 20 to 30 knots especially over the outer coastal waters beyond 60 NM out. SCA remains in effect with possibility of Gale conditions in outer most waters where gusts could be in excess of 35 to 40 knots and wave heights could build as high as 15 feet. Have kept Gale watch in effect for the possibility of these conditions on Thursday. Helene will push inland on Friday with winds shifting to westerly in its wake. Unsettled marine conditions will gradually improve by Friday afternoon as the pressure gradient relaxes. Conditions continue to gradually improve through the weekend. /TJS/ && .PRELIMINARY POINT TEMPS/POPS... MCB 64 83 60 80 / 10 0 0 0 BTR 69 88 64 85 / 10 0 0 0 ASD 69 86 64 84 / 10 0 0 0 MSY 73 86 67 84 / 40 0 0 0 GPT 69 85 65 84 / 10 10 0 0 PQL 71 87 66 86 / 20 10 10 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...Small Craft Advisory until 4 PM CDT Friday for GMZ530-532-534- 536-538-550-552-555-557-570. Small Craft Advisory until 7 AM CDT Thursday for GMZ572-575-577. Small Craft Advisory from 1 AM to 4 PM CDT Friday for GMZ572-575- 577. Gale Watch from 7 AM CDT Thursday through late Thursday night for GMZ572-575-577. MS...None. GM...Small Craft Advisory until 4 PM CDT Friday for GMZ532-534-536- 538-550-552-555-557-570. Small Craft Advisory until 7 AM CDT Thursday for GMZ575-577. Small Craft Advisory from 1 AM to 4 PM CDT Friday for GMZ575-577. Gale Watch from 7 AM CDT Thursday through late Thursday night for GMZ575-577. && $$ SHORT TERM...TJS LONG TERM....TJS AVIATION...TJS MARINE...TJS