textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 539 AM CDT Sun Sep 27 2026

- During the latter part of this week, a period of more active weather appears likely. While there is still significant uncertainty regarding the specifics, heavy rain could become a concern mainly Friday into the weekend.

SHORT TERM

(Now through Wednesday) Issued at 1036 PM CDT Sat Sep 26 2026

Very nice weather through mid week expected. A back door front(dew pt boundary) will move into the area Monday to reinforce the dry air then back off Tue ahead of a warm frontal feature that will be a line between the deeper moisture moving in and the dry air moving out for Wed. The area will still remain marginally capped by an H5 high over the area so there are no real numbers that show any strong storms Wed, but mostly showers should break out over the area with one or two storms possible.

LONG TERM

(Wednesday night through Saturday) Issued at 1036 PM CDT Sat Sep 26 2026

A fairly strong H5 ridge will remain centered directly over the area Wednesday night into Thursday, and this will keep conditions warm and dry aloft. As a result, mid-level lapse rates will remain very paltry and overall instability will be limited with SBCAPE only peaking around 500 J/KG in the afternoon hours. An increasing southeast flow regime on the southwest periphery of a surface to mid- level ridge axis centered over the western Atlantic will help to usher in moisture beneath the elevated capping inversion, but the strong cap will greatly limit convective development throughout the day. Although PWATS will be near average for this time of year, overall convective coverage will be limited to isolated to widely scattered development. Additionally, temperatures will continue to run warmer than average in the lower 90s for Thursday afternoon. Any convection should also remain fairly weak and low topped given the lack of instability expected to be in place, and PoP values of 20 to 30 percent should adequately represent the overall rain threat for the day. Any convection will quickly wane with the loss of daytime heating, and Thursday night will be dry and cool as lows dip into the upper 60s and lower 70s.

The pattern will begin to shift to a much wetter regime as we move into Friday and Saturday. The H5 ridge axis will shift to the east, and this will allow for a deep layer southeast flow regime to develop over the area. At the same time, a deepening shortwave trough to the east will spread increasing positive vorticity advection and greater lift over the area. The influence of the PVA will be most substantial on Saturday when a weak vorticity maxima moves in from the Gulf and merges with the broader trough axis over the southern Plains and Texas. A surge of deep tropical moisture from the southern Gulf will accompany this weak vort max, and this will push PWATS up from around the 90th percentile or near 2 inches on Friday to near the daily max of around 2.5 inches by Saturday. Lapse rates will be moist adiabatic and H5 temperatures will support warm rain processes as we move into next weekend. Hourly rainfall rates of 2 to 3 inches per hour can be expected on Friday and Saturday. Convective activity will also continue to develop during the overnight hours on Friday and Saturday due to the favorable forcing aloft. Given all of these conditions, flash flooding will be an increasing concern for the area on Friday and Saturday. Another issue to monitor will be the potential for a few severe storms to form. 0-3km storm relative helicity peaks around 200 m2/s2 Friday night into Saturday morning. Although the severe threat will remain minimal, the threat of a few tornadoes forming will be in place with the favorable shear parameters mentioned. We will continue to monitor the situation as we move through next week and adjust the forecast accordingly. Given the extensive rainfall and cloud cover, temperatures will be cooler with highs in the mid to upper 80s. The high humidity will keep lows in the 70s.

AVIATION

(12Z TAFS) Issued at 539 AM CDT Sun Sep 27 2026

VFR through this cycle.

MARINE

Issued at 1036 PM CDT Sat Sep 26 2026

Winds over all coastal waters will remain light and sometimes variable through Monday. Winds will become predominantly SE by Tuesday at around 10 knots the rise further into mid next week to around 15 to 20 knots as a cold front approaches the coast.

LIX WATCHES/WARNINGS/ADVISORIES

LA...None. GM...None. MS...None. GM...None.