Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
015 FXUS64 KLIX 030740 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 240 AM CDT Thu Sep 3 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .KEY MESSAGES... Updated at 236 AM CDT Thu Sep 3 2026 - Scattered to numerous showers and storms are forecast each day through this weekend. While the overall severe weather threat will be low, one or two storms could become strong to severe each day, producing strong to damaging wind gusts, frequent lightning and periods of heavy rain. - Above normal temperatures expected most of the 7-Day forecast period. Afternoon heat indices will generally range from 100 to 107 degrees. && .SHORT TERM... (Now through Sunday) Issued at 236 AM CDT Thu Sep 3 2026 (Today through Sunday) A broad upper level ridge centered near the Tennessee Valley into the Carolinas early today will gradually retrograde westward today and tomorrow while a weak easterly disturbance moves across the central Gulf Coast. For today, forcing remains rather weak, so convection should largely be driven by the typical sea/lake breeze circulations and lingering outflow boundaries. Deep moisture remains in place with PWATs over 2 inches, supporting scattered afternoon convection and locally heavy rainfall with the stronger storms. Highs should reach the lower to middle 90s, a few degrees above normal for early September, with peak heat indices generally around 100 to 107 degrees. Forecast soundings remain quite moist through the column but do show a dry slot aloft as well as inverted-V signature at the surface. As a result, storms will need to be monitored for marginally severe downburst threat where greater heating allows instability and DCAPE to locally increase before storms develop. By Friday, the easterly wave in the northern Gulf will be moving farther west across the area while the midlevel ridge continues its gradual shift toward the mid Mississippi Valley and Southern Plains. This should provide a somewhat more favorable environment for convection, with increasing low-level convergence and abundant moisture allowing storms to develop earlier near the coast before spreading inland through the afternoon hours. Rain chances will consequently be considerably higher than today, with scattered to numerous storms possible. Greater cloud cover and earlier convection should keep highs mainly in the upper 80s to around 90, although areas that avoid storms longer could still reach the low/mid 90s. Soundings remain fairly moist, so widespread damaging winds are not as likely as today. However, any localized midlevel drying combined with stronger pre-convective heating could increase DCAPE enough to support an isolated strong to marginally severe downburst. Over the weekend, the upper level ridge becomes centered farther west over the southern Plains while the local area remains along its southeastern periphery. At the same time, troughing begins to deepen across the eastern CONUS, with the resulting weakness aloft continuing to support daily convection. Saturday should remain fairly active given the lingering deep moisture, with scattered to numerous mainly afternoon storms developing along mesoscale boundaries. Highs will generally remain in the lower to middle 90s with heat indices again around 100 to 107 degrees before convection provides some relief. As the ridge shifts farther west and flow aloft becomes somewhat more northerly, forecast profiles may begin to show slightly more midlevel drying compared to earlier in the period. If this occurs, increasing DCAPE and a better-defined inverted-V structure could modestly increase the potential for isolated strong downbursts, particularly where storms develop after prolonged heating. MEFFER && .LONG TERM... (Sunday night through Wednesday) Issued at 236 AM CDT Thu Sep 3 2026 (Sunday through Wednesday) Moving into next week, the forecast area will be positioned between a broad upper level ridge centered over the southern Rockies and a longwave trough across the eastern seaboard. the end result is that the area will find itself beneath a deep mid to upper level north- northeasterly flow pattern. A weak backdoor front will slide into the area on Sunday, stall, and then gradually dissipate on Monday. PWATS will be near seasonal averages and moisture will pool along and ahead of the front. This moisture will combine with forcing along the boundary to support convective development each day. The convective activity may be a bit delayed until the mid to late afternoon hours as convective temperatures climb more into the mid 90s. This is due to some drying and warming aloft associated with the deep layer north- northeast flow regime. However, ample low level instability as noted by MLCAPE values of around 1500 J/KG each afternoon will be sufficient to overcome any weak capping aloft and allow for showers and storms to fire up. The convection should generally remain below severe limits over this period, but conditions do look more favorable on Monday for some strong to severe downburst wind events to occur. A surge of drier mid-level air and steep lapse rates over 8.0 C/km below 850mb will allow DCAPE values to climb to around 1100 J/KG, and these values are supportive of strong downburst wind events. PoP each afternoon will peak around 50 to 60 percent to reflect the convective risk as the backdoor front moves in and stalls over the area. Temperatures will also be slightly warmer than average in the low to mid 90s as the drier air and later convective initiation allows for more daytime warming to occur. Heat index values will likely exceed advisory levels as we move into the weekend and HeatRisk is projected to move into Major category by Saturday. Anyone participating in large outdoor events and activities should take extra heat precautions on Sunday and Monday. Tuesday will be a bit drier day as the front over the area fully dissipates and the troughing to the east pulls away. This will allow the ridge over the southern Rockies to spread eastward through the Lower Mississippi Valley. As the ridge strengthens, drier and warmer air will feed into the mid-levels between 700 and 500mb. PWATS will fall below average and any convective development will be more isolated to widely scattered. Any convective activity should also be more confined to the seabreeze. The one concern on Tuesday will once again be the increased potential for some damaging downburst wind events to occur with the deepest updrafts that climb above 30k feet. The drier air in the mid-levels could easily entrain into the deeper updrafts leading to evaporative cooling and downburst development. This is supported by steep lapse rates over 8.0C/km below 850mb and DCAPE of around 1200 J/KG Tuesday afternoon. Beyond the threat for a few damaging wind events, temperatures will remain very warm with highs climbing back into the low to mid 90s. However, the drier air aloft mixing down into the boundary layer should keep heat index readings just below advisory levels as we move into Tuesday. Wednesday will see the mid to upper level ridge axis shift more toward the Tennessee Valley. This will open up a deep layer southeast flow regime into the region, and moisture will feed back into the area. PWATS will rise to around the 75th percentile and rain chances will increase. Ample instability will be in place with MLCAPE of 1500 to 2000 J/KG expected, and the convective activity will also start earlier in the day with storms firing up on the coast in the mid to late morning hours and then spreading inland through the afternoon. Higher PoP of 50 to 70 percent and temperatures closer to seasonal norms in the low 90s can be expected. && .AVIATION... (06Z TAFS) Issued at 236 AM CDT Thu Sep 3 2026 VFR conditions will prevail at all of the terminals through the early morning hours. As we move beyond 15z, another round of scattered showers and storms will fire up as temperatures warm. Low level convergence will be maximized along coastal areas and PROB30 wording with gusty winds and MVFR visibility and ceiling restrictions is in place at most local terminals for a few hours after 18z. Any impacts will be short-lived at an hour or less as the storm cells quickly pass through. MEFFER && .MARINE... Issued at 236 AM CDT Thu Sep 3 2026 The pressure gradient is expected to be fairly weak the next several days, lending to quite benign marine conditions over marine areas. This pattern will maintain winds generally 10 knots or less through the weekend with seas around 1 to 2 feet. The main potential impacts comes from daily rounds of isolated to scattered thunderstorms. Those will have the potential to produce locally higher winds and waves. MEFFER && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...ME LONG TERM....ME AVIATION...ME MARINE...ME