textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 620 PM CDT Wed Apr 29 2026

- There is a Marginal to Slight Risk of severe weather with the greatest potential in southwest MS and adjacent LA parishes this afternoon and evening.

- There is a Marginal Risk for heavy rainfall this afternoon and evening and a Marginal to Slight Risk of heavy rainfall Friday night. For the Friday night evening, the greatest potential sill be in southwest Mississippi and Baton Rouge Metro.

UPDATE

Issued at 620 PM CDT Wed Apr 29 2026

Convection continues to sag southward out of Mississippi, with leading edge from about New Roads to Bogalusa to Picayune at 615 pm CDT. Trend has been for weakening over the last hour or so, with the main focus in the next few hours from about Interstate 55 eastward to the north of Interstate 10. There is still scattered convection to the northwest of our area, so we may not dry out completely. Near term issue may be more of a heavy rain threat than a severe weather threat, with 1 to 2 inch rainfall totals in an hour or so in several areas.

Convection hasn't quite moved far enough to clear any of Severe Thunderstorm Watch 181 (expires at 9 PM) yet, but may be able to clear a few counties/parishes in the next hour or so.

SHORT TERM

(Now through Thursday night) Issued at 102 PM CDT Wed Apr 29 2026

Upper level analysis shows a ridge centered over Mexico by flattened on its northern side due to a trough axis coming across the mid and upper Mississippi RIver Valley. A cold front along the southern edge of the trough has pushed into Texas and extends across northern LA and MS. As storms develop along this focal point, cold pool will likely drive the activity southeastward towards the CWA. Model soundings are similar in some facets but also quite different when looking at KBTR vs KMCB. In southwest MS, storms should be surface based as 700-850mb layer cools quite a bit between late morning and early afternoon. That'll support more robust updrafts as CAPE values jump to the 2000+j/kg realm. Low level shear not much to speak of but do have decent 0-6km shear at 50kts or so. Hail and damaging winds will be the main threats. When it comes to flash flooding, not the biggest concern but worth noting. Depending on the strength of the cold pool dragging storms south, if its not strong enough, could get some W/E training to produce upwards of 3 to 4 inches of rainfall. Generally, it takes more than this to produce flash flooding in southwest MS, but not in the isolated more urbanized areas there. Looking farther south in the CWA, lack of low level cooling will really limit instability comparatively and stunt updraft potential.

As the main trough axis passes east of the CWA Thursday, the base of it pulls northward. That puts the CWA in more of a zonal flow pattern. So wherever the cold front ends up by then is probably were it will stay for the time being. High temp gradient across the local area will be much higher than typical, ranging from mid/upper 70s north of the boundary to mid 80s south of it. Moisture convergence along this boundary will probably aide in development of scattered showers and possibly some thunderstorms throughout the day.

LONG TERM

(Friday through Tuesday night) Issued at 102 PM CDT Wed Apr 29 2026

Southwesterly flow increases in the mid and upper levels overhead Friday as an upper level low comes into the southwestern US, reaching the 4 Corners region late in the day. This setup will first lead to a fairly substantial cirrus deck over the CWA Friday. That, combined with east to northeast surface flow will yield even cooler highs. Will be the first time in about a week that highs struggle to reach climatological normal. Friday night into Saturday though, rain chances come up considerably as a shortwave coming across AZ through TX merges with broad upper trough to the north. As the track of this feature nears the local area, frontogenesis will be taking place over the northern Gulf Coast. That setup with lead to both surface and upper level height falls. Combine that with PW's 1.75-2" along with W/E orientation of convective development/movement, and you've got a decent setup for heavy rain/flash flooding potential.

Sharpening of the main trough Saturday morning will drive the cold front well into the Gulf and bring much cooler air to the local area through Monday. Look for highs in the 70s this weekend and lows 40s to near 50. Early next week looks to be non-impactful characterized by moderating temps as the upper level trough lifts and slight ridging builds in to the region from the south.

AVIATION

(00Z TAFS) Issued at 620 PM CDT Wed Apr 29 2026

Most terminals VFR at issuance, with the exception of KMCB, which had TSRA in the area. Will use TEMPO TSRA for evening storms at KMCB, KBTR, KHDC, KASD, KGPT. Questionable whether storms will reach remaining terminals tonight as current convection has shown a weakening trend. Do expect MVFR conditions later tonight at most or all terminals. Can't entirely rule out TSRA later tonight after the current batch, which could require further amendments. The more likely solution is TSRA refiring Thursday afternoon, and will use PROB30 for right now at all terminals tomorrow afternoon.

MARINE

Issued at 102 PM CDT Wed Apr 29 2026

Persistent onshore flow of 10 to 15 knots will remain in place through this with high pressure generally centered east of the local coastal waters. Seas will remain well below any hazardous limits at 1 to 3 feet through this period. As we move into the back half of the week, we will see a weak cold front drift south towards the coast and stall along the northern Gulf Coast. That'll lead to both weaker winds overall as well as north or south winds depending on coastal zone's location in related to the boundary. A stronger upper level trough moves through the region Saturday morning. Expect to see at least Exercise Caution, possibly low in Small Craft Advisory, conditions behind this front.

LIX WATCHES/WARNINGS/ADVISORIES

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