


Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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814 FXUS64 KLIX 100555 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1255 AM CDT Thu Jul 10 2025 ...New AVIATION... .SHORT TERM... (Thursday through Saturday Night) Issued at 1033 PM CDT Wed Jul 9 2025 A weak trough extending from the Northeastern CONUS into the Deep South will continue to bring higher than average rain chances to the forecast area through Friday. A pool of deeper moisture associated with this weak trough axis will keep precipitable water values between the 75th and 90th percentiles, or around 2 inches, through Friday. This deep and plentiful moisture will combine with ample instability as temperatures climb into the lower 90s to produce scattered to numerous showers and thunderstorms each day. Thunderstorm activity will generally form along the seabreeze/lakebreeze initially and then spread outward on outflow boundaries from decaying storms through the afternoon and early evening hours. The increased omega aloft associated with the trough will help the updrafts to maintain themselves longer than in a typical Summer pulse thunderstorm situation, and this could lead to some localized spots receiving higher rainfall totals than typically seen on a July day. However, only isolated street flooding in poorly drained and highly urbanized areas is the primary concern with any storms that form both on Thursday and Friday. Given the highly diurnal nature of the convection, largely dry conditions are expected from mid to late evening into the early overnight hours. By Saturday, the weak trough is expected to fully dissipate and stronger upper level ridging will begin to build in from the east. As this ridge builds in, increasing deep layer subsidence will lead to both warming and drying in the mid and upper levels. The end result will be a reduction in overall instability as a weak mid-level capping inversion forms. Precipitable water values will also begin to drop with readings closer to average on Saturday, or around 1.8 inches. Thunderstorm activity will tend to start later in the day and be more scattered than observed on Thursday and Friday. The drier air aloft could also more easily entrain into the deeper updrafts, and this could lead to a few more wet microburst events Saturday afternoon. This is supported by downdraft CAPE values of around 1200 J/KG. These values are significantly higher than those expected on Thursday and Friday. The convection will also die off more quickly with largely dry conditions expected by the early evening hours. Temperatures will be slightly warmer due to the combination of less cloud development and the subsidence aloft. Highs will warm more into the low to mid 90s and heat index readings will be closer to 105 instead of 100. && .LONG TERM... (Sunday through Wednesday night) Issued at 1033 PM CDT Wed Jul 9 2025 The upper level ridge will continue to build over the region on Sunday and is expected to remain in place through Wednesday. The increased subsidence aloft will keep precipitable water values close to the median for this time of year, or between 1.7 and 1.8 inches, and this will result in lower convective coverage each day. Shower and thunderstorm activity will be more scattered and short-lived due to the lack of any deep layer forcing mechanisms to support sustained updrafts. Unfortunately, the drier air aloft will also continue to entrain into the deepest updrafts, and the potential for wet microbursts will remain higher than average. The thunderstorms will be diurnally induced with convection peaking in the afternoon hours as the seabreeze/lakebreeze intensifies and serves as a focusing mechanism for convective development. Temperatures will also be above normal with most locations climbing into the mid 90s each day. Although rain chances will be lower and dry air will be in place aloft, surface dewpoints will remain high in the mid to upper 70s through the period. As a result, oppressive heat will be a concern starting on Sunday and continuing through the end of next week. Heat index values are highly probable to exceed heat advisory criteria of 108 degrees each day. On average, maximum heat indices should range between 108 and 112 through the long term period. && .AVIATION... (06Z TAFS) Issued at 1250 AM CDT Thu Jul 10 2025 Overnight hours will generally be VFR. With precipitable water values near 2 inches, expect scattered to numerous SHRA and scattered TSRA. Activity could start as early as 15z or so, but should primarily be between 17z-23z. For much of that period, will use prevailing SHRA and PROB30 TSRA. Beyond 00z Friday, will go VFR for now through end of package Friday. && .MARINE... Issued at 1033 PM CDT Wed Jul 9 2025 Outside of the threat of thunderstorms capable of producing waterspouts, gusty winds, higher waves, and lightning, conditions across the coastal waters will remain relatively benign. A broad ridge over the Gulf will keep winds from the south and southwest at 10 knots or less through the period and seas will remain 2 feet or less in the open Gulf waters. In the nearshore waters and lakes, the seabreeze cycle will lead to more variable wind directions with a light northerly flow of less than 10 knots in the early morning hours shifting to a stronger southerly flow of 10 to 15 knots in the late morning and afternoon hours each day. Thunderstorms will tend to form along the landbreeze boundaries in the early morning hours and then linger into the late morning before shifting inland. && .PRELIMINARY POINT TEMPS/POPS... MCB 90 71 91 72 / 70 20 80 40 BTR 90 75 92 74 / 70 20 80 40 ASD 91 74 92 74 / 70 20 80 50 MSY 92 77 92 78 / 60 20 80 40 GPT 91 75 91 76 / 60 40 80 50 PQL 92 74 91 74 / 50 40 80 50 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...PG LONG TERM....PG AVIATION...RW MARINE...PG