textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 506 AM CDT Tue Apr 28 2026

- Well above average high temperatures in the upper 80s and lower 90s will continue through Wednesday. Heat index values will climb into the mid to upper 90s.

- There is a Marginal Risk for heavy rainfall Wednesday afternoon and evening, mainly in southwest Mississippi and adjacent Louisiana parishes.

- The threat for thunderstorms, some possibly strong to severe will start Wednesday and continue through the weekend.

SHORT TERM

(Now through Wednesday night) Issued at 1125 PM CDT Mon Apr 27 2026

Most sh/ts activity will be found just north of the area today and a good portion of Wed. But the frontal boundary supporting this activity will sink southward by late in the day Wed. This will likely be more due to the storms along this boundary cold pooling and forcing the boundary south with them. Most of the area should see some rain from this Wed evening into the overnight hours as it weakens. The boundary becomes quasi-stationary over the area and will continue to help produce sh/ts after Wed. These storms moving in for late Wed will take advantage of the heat and bouancy that it will provide, so a severe storm is very possible with these. SPC has a marginal risk at the moment and that looks to suffice.

LONG TERM

(Thursday through Monday night) Issued at 1125 PM CDT Mon Apr 27 2026

By Thursday, the upper flow across the southern states is almost zonal with one leg of the trough to our northeast moving off the Atlantic Coast and the next dropping southward over the Dakotas. To the west, troughs should be off the British Columbia coast and southwest of San Diego. Both operational medium range runs agree on a frontal boundary along Interstate 10 during the day on Thursday. The trough southwest of San Diego will move eastward across the lower Mississippi River Valley Friday night into Saturday, eventually pushing the frontal boundary out into the Gulf. The trough off the British Columbia coast is acting as the kicker for that trough, and eventually bringing drier air into the area by Sunday as it moves across us. Ridging will eventually begin rebuilding into Texas early next week.

The frontal boundary over the area on Thursday will have already taken the edge off of the heat, knocking high temperatures down by at least 5 degrees from Wednesday, and it may be more than that, if we don't get much sunshine. Precipitable water values will still be in the 1.5 to 1.6 range on Thursday (90th percentile), so there's still plenty of moisture available to aid convective development. Moisture levels will remain high through Friday night, when the southern stream trough moves through.

Expectation would be for perhaps scattered convection Thursday and during the day Friday, with a more substantial area of showers and storms overnight Friday night into Saturday, prior to the drier air arriving Saturday night and Sunday, with no precipitation beyond that point.

Thursday and Friday high temperatures will be highly dependent on precipitation and cloud cover. Current NBM deterministic numbers for Thursday are closer to the cooler ECMWF operational solutions. By Friday, the GFS operational numbers are roughly 5 degrees higher than even the warmest ECMWF ensemble member, and are probably too warm considering the location of the front. From the daytime hours Saturday onward, the operational GFS, ECMWF and NBM deterministic are in pretty good agreement.

AVIATION

(12Z TAFS) Issued at 506 AM CDT Tue Apr 28 2026

Most terminals have VFR cigs this morning, but some quick cigs in MVFR and IFR range could move over until mid morning then all VFR again. This same cycle will repeat again tonight, mostly likely just as early.

MARINE

Issued at 1125 PM CDT Mon Apr 27 2026

Persistent onshore flow of 10 to 15 knots will remain in place through the middle of this week with high pressure generally centered east of the coastal waters. Seas will remain well below any hazardous limits at 1 to 3 feet through the period. As we move into the back half of the week we will see a cold front moving towards the north central gulf coast, possibly bringing stronger winds and a shift to northerly by the weekend.

LIX WATCHES/WARNINGS/ADVISORIES

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