textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 1203 AM CDT Wed Mar 11 2026

- Patchy light to moderate fog will be possible tonight mainly along the coast and over portions of southern MS but overall the threat of dense fog appears low.

- A strong trough will move through the region late Wednesday. This will drive a cold front across the region with showers and thunderstorms impacting the area during the overnight hours Wednesday night. This system will have the potential to bring a few strong to severe storms with all modes of severe weather possible, and the entire area will have the potential of seeing strong to severe storms. Residents should continue to monitor the forecast for updates as this threat evolves.

- In the wake of the cold front, much cooler and drier air will move into the area for about 36 to 48 hours Thursday into Friday. Temperatures will moderate quickly for the weekend, but another shot of much cooler air will arrive Sunday night.

SHORT TERM

(Today through Thursday) Issued at 1203 AM CDT Wed Mar 11 2026

Ridging was centered over the eastern Gulf this evening, with a southern stream trough moving into west Texas. A northern stream trough was moving through Wyoming. At the surface, high pressure was centered from the western Atlantic into the eastern Gulf. Low pressure over New England had a frontal boundary along the southern edge of the Great Lakes to near Chicago, to a low pressure center over southeast Kansas, then southwest into west Texas. Locally, southerly winds continue to bring moisture into the area with mid- evening temperatures in the mid 70s. Dew points were in the upper 60s to lower 70s. The evening LIX upper air sounding carried a precipitable water value of 1.42 inches, which was near the 90th percentile for early March. There was a bit of a cap around 800 mb.

The west Texas upper trough will spend most of Wednesday traversing the Lone Star State, moving into Louisiana around sunset, and exiting the local area Thursday morning. The 18z GFS looks to be a bit on the quick side as compared to most of the other model solutions, but only by a few hours.

For much of the day on Wednesday, the airmass will be a bit drier than the current sounding shows, with precipitable water values near 1.2 inches. The cap is expected to be gone, but the best forcing will be to the west. Cannot rule out isolated to scattered showers late in the afternoon, but expect the greatest threat of thunderstorms to hold off until beyond sunset. A line of thunderstorms is expected to develop over east Texas during the midday hours and move eastward into western Louisiana. By sunset, the line of storms is expected to be approaching the Atchafalaya River. Just ahead of the front, precipitable water values are expected to increase to above 1.5 inches, CAPE values will be around 1000 J/kg and bulk shear increases to 40 to 50 knots. With low level SRH values around 100, there's going to be potential for supercells capable of all hazards. The best lift will be pulling away from the area to the northeast, so convection may already be in a weakening mode as it arrives, but probably not quick enough to lower our guard at this point. We'll also have to keep an eye on the potential for heavy rainfall, especially north of the Interstate 10/12 corridor where heavy rain fell Saturday night. Rainfall totals of 1-2 inches, locally higher, certainly appear to be realistic across the north half of the area. The main line of convection looks to be moving into Alabama by about 3 AM CDT, if not a little sooner.

Behind the front, significantly cooler and drier air will arrive on strong northerly winds. Dew points that will be in the upper 60s to around 70 on Wednesday afternoon are expected to be in the mid 30s just 24 hour hours later. Highs in the lower and mid 80s Wednesday could be 15-20 degrees cooler on Thursday. In this scenario, the NBM numbers aren't likely to catch the magnitude of the drying, and NBM25 might be a good starting point. That will probably take afternoon RH values to near or below 30 percent. Fortunately, fuels should be fairly wet. Not out of the question that we may also need a Wind Advisory for portions of the area very late Wednesday night into Thursday, but will defer that call to the day shift for now.

LONG TERM

(Thursday night through Tuesday) Issued at 1203 AM CDT Wed Mar 11 2026

Upper flow becomes quasi-zonal pretty quickly Thursday night, and the surface high will slide east quickly to be centered from the Carolina coast to the Texas coast by Friday morning. Winds will already have turned back to an onshore component by midday Friday, with moisture gradually returning, as well as warming temperatures.

That will set the stage for the next weather system. A strong northern stream shortwave trough will develop low pressure that will move through the middle Mississippi River Valley into the Ohio Valley on Sunday. That will eventually drive a cold front through the local area Sunday night. Moisture availability looks to be rather meager with that front though, so we might end up with little more than a band of rain showers just ahead of the front. Again behind that system, cooler and drier air will plunge into the area briefly for Monday and Tuesday.

Temperatures will be on a roller coaster during this portion of the forecast. Morning lows Friday morning will be rather chilly as compared to the past couple weeks. Areas north of the Interstate 10/12 corridor could see lows around 40 Friday morning, which we haven't seen since February 24th. However, things will recover quickly and highs could be in the 70s by Friday afternoon. Saturday and Sunday will see above normal temperatures, and guidance is pretty close on those, although the NBM looks a bit closer to the ECMWF solutions. For now, on Monday and Tuesday, will just ride with the NBM numbers as the ECMWF and GFS disagree on just how much cold air dumps into the local area. The ECMWF solution shunts most of the cooler air off to the east, only taking us back to around normal, while the GFS drops lows into the 30s across the northern half of the area Tuesday morning.

AVIATION

(06Z TAFS) Issued at 1203 AM CDT Wed Mar 11 2026

Wide range of conditions at issuance time from IFR (at KGPT) to VFR. Most or all terminals will see MVFR ceilings develop and gradually lower to near FL010 or lower well before sunrise. Expect improvement to MVFR by mid-morning Wednesday, with most at VFR around midday. Could see a few SHRA/TSRA at western terminals prior to 00z Thursday, but main thrust of convection along the cold front will be in the 00z Thursday to 06z window. Will carry TEMPO IFR conditions with the convection and linger precipitation several hours behind the front. Will not mention strong wind gusts with the convection for now, but may be necessary in later updates. Gusty northwest to north winds likely behind the frontal passage, but at most terminals, that will be beyond 06z Thursday.

MARINE

Issued at 1203 AM CDT Wed Mar 11 2026

The low pressure to the west and high pressure to the east drive onshore flow through the timeframe of the frontal passage tonight. Wind speeds will increase from the current 10 kt to around 15 kt immediately preceding the frontal passage. Showers and thunderstorms will accompany the front, likely producing strong thunderstorm winds and perhaps a few waterspouts. Small Craft Advisories have been issued for late Wednesday night through Thursday afternoon. We could even see a period of Gale conditions during the day into Thursday evening, but confidence not high enough to issue gale products at this time. Conditions should improve quickly on Friday, continuing through much of the weekend. Another strong cold front will produce hazardous marine conditions late Sunday night or Monday.

LIX WATCHES/WARNINGS/ADVISORIES

LA...None. GM...Small Craft Advisory from 1 AM to 7 PM CDT Thursday for GMZ530- 532-534-536-538-550-552-555-557-570-572-575-577.

MS...None. GM...Small Craft Advisory from 1 AM to 7 PM CDT Thursday for GMZ532- 534-536-538-550-552-555-557-570-572-575-577.