textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 1024 PM CDT Mon Sep 28 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 Friday) Issued at 1024 PM CDT Mon Sep 28 2026

Dry air coming in the back door this morning. One can easily see this when moving NE away from our area as dew pt temps fall from around 70F into the lower 60s. This will be the last surge before we get into the higher moisture content air. The low level flux will occur first and should slowly begin to filter in by late Wed night, depending which guidance is looked at. Some, like the GFS, have this sfc moisture coming in Thu. At some point though, this will occur and it will only be able to produce showers and maybe a stray storm as we will still be capped by the mid/upper ridging. Then the tropical wave moves in with a much deeper moisture profile and this should be quite rapidly done at some point during the day Friday. The depth of moisture will be enough to get more storm activity and the area where the main moisture axis comes inland is where the wettest and stormiest area will be obviously. At the moment, that is a harder problem to solve since the movement of this axis with successive model runs will continue to be shifty. There is some weak agreement in some globall suites but the soonest time frame when we should see most, if not all, model consensus will be Wed, on either the 7a or 7p model runs.

LONG TERM

(Friday night through Monday) Issued at 1024 PM CDT Mon Sep 28 2026

Seasonable dew points and PWATs of the short- term period will give way to increasing moisture with a return flow regime advecting gulf air into the area on Thursday. This will continue the conditioning process of the atmosphere headed into the weekend with increasing PoPs each day. Global model guidance continues to support the arrival of a tropical wave into the area by Friday which will bring a surge of deeper tropical moisture sending PWATs toward daily record maximums (>2.3 inches). This will promote widespread, daily afternoon convective activity with storms capable of highly efficient rainfall rates exceeding 2 to 3 inches per hour. This will increase the risk for localized to areas of flash flooding, especially for urban and poor drainage areas.

The largest caveat to a higher threat for excessive rainfall will be the continued trend of a stronger western periphery of the ridge prevailing across the area into the weekend. The stalled trough over the central CONUS that is delivering ample lift over deep tropical Pacific moisture from the remnants of Hurricane Polo remains stuck and weakens under the expand ridging. The only scenario to watch for some residual lift will be with the lifting weak shortwave on Saturday into Sunday. The main window for the excessive rainfall risk will be Friday through Sunday. It's favored that elevated moisture and the wetter pattern will persist into the following week as we don't see a strong frontal passage clearing out this moisture field just yet. However, a strong east CONUS trough pattern is being hinted at in the long-range ensemble means that will favor a more notable potential for our first real fall front going into late next week. We shall see.

AVIATION

(06Z TAFS) Issued at 1024 PM CDT Mon Sep 28 2026

VFR through this cycle.

MARINE

Issued at 1024 PM CDT Mon Sep 28 2026

Winds will become predominantly SE today at around 10 knots then rise further as the week progresses to around 15 to 20 knots as a cold front approaches the coast. Showers and some thunderstorms will begin to increase in coverage toward the end of the week as well as a tropical wave moves through the northern gulf.

LIX WATCHES/WARNINGS/ADVISORIES

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