textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 1229 PM CDT Tue May 26 2026

- Heavy rainfall continues to be the main weather threat through the week. Some of the stronger storms will be capable of producing hourly rainfall rates of 1-3" per hour. With mostly saturated soils, high rainfall rates even over short periods could overwhelm drainage systems, leading to ponding of water in low lying and poor drainage areas. Localized flash flooding could also result in some roads becoming impassable, mainly in areas where the heaviest rain falls, or where multiple storms result in longer periods of moderate to heavy rain.

- A Flood Watch will be in effect through 7 PM Tuesday generally for areas from the New Orleans metro eastward through the Mississippi Coast including the north shore. Elsewhere, the flood threat will be lower, though isolated flooding could still occur.

- A Flood Watch is in effect for our entire area Wednesday and Wednesday evening. Additional Flood Watches may be needed, especially Thursday.

SHORT TERM

(Now through Friday night) Issued at 1229 PM CDT Tue May 26 2026

Tonight through tomorrow morning, there will be a lull in shower and storm activity generally. We are not expecting much if any rainfall overnight. Looking at the CAMs and global models, there is an MCS complex moving across western Louisiana tonight, which could make it into our area by around 12-14z (7-9am). It is expected to weaken and slow as it approaches the area, which could cause some training for our northwest areas as it stalls. Some gusty winds (40-60mph) will be possible with these storms as well for our northwest areas, but we are not expecting these storms to be severe.

Flash flooding will be a concern with these storms as they approach the northwest areas. Flash flooding will also be a concern for areas east of I-55 as the morning trends in the CAMs show a consensus boundary that sets up tomorrow around 10am along a line from Houma to Picayune, including New Orleans and the northshore of Lake Pontchartrain. So, we have 2 main focus areas for flash flooding concerns: the approaching synoptic MCS from the west that is expected to stall over western areas around 7a-1p CT tomorrow and a stalled mesoscale boundary for areas east of I-55 that will set up around 10a-6p CT tomorrow. For both of these areas, the concerns and potential impacts from flash flooding will be the same. Abundant moisture combined with a decent LLJ, decent instability, and high PWs (above the 90th percentile for SPC sounding climatology) will caused enhanced potential for flash flooding issues. Rainfall rates will be generally 1-3 inches per hour, as these storms will be highly efficient. This is especially the case for areas that have seen widespread rainfall over the weekend. Additionally, minor to moderate rises for area rivers will be expected from these storms.

Saturated antecedent conditions and favorable flash flooding conditions will make runoff quicker and enhance flash flooding impacts. And the high effiency of the rainfall will be of particular concern for areas that are saturated and for urban areas, which is at this point our entire area. Though we do have higher concerns for the MS Coast due to the remarkable rainfall totals that area has seen over the last few days as well as New Orleans and Baton Rouge for their urban vulnerabilities.

So, we have discussed the potential for heavy rainfall and the concerns, but what does this look like in terms of impacts? Well, we have several concerns. A lot of the potential impacts will be the same or similar to what we saw over the weekend. So, there is potential for water over roadways, which could cause some roadways to be impassable or closed, especially urban or saturated areas. Of note for New Orleans is the concern for ponding of low-lying roads, underpasses, and poor drainage locations. Keep in mind that underpasses will flood before other roadways. And then for river- adjacent locations, there is concern for water to be approaching structures along rivers, mainly for the flashier rivers along the MS Coast.

Thursday into Friday, an MCS will move through the area slowly, which will enhance flash flooding concerns again. The environment will still be quite conducive to flash flooding, even moreso than today or tomorrow. And the timing of these storms will be less certain, since we are still several days out and CAMs haven't fully weighed in. But we would expect concerns similar to the past few days for Thursday and Friday. MSW

LONG TERM

(Saturday through Monday night) Issued at 1229 PM CDT Tue May 26 2026

Saturday through early next week, there is a lot of model uncertainty. There are still several days out, so a lot may change between now and then, especially given the lack of reliabiltiy in the models lately as they struggle with this pattern. Generally, ridging looks to build back over the area, and we start to see more of a typical pattern for this time of year. Afternoon and evening showers and storms will be expected Saturday, Sunday, and Monday, which will have some risk of localized flash flooding and strong storms. We are not expecting severe weather over the weekend at this time, and generally coverage looks to be moreso around 30-50%. So, expected isolated to scattered afternoon/evening showers and storms over the weekend, closer to our climatology for May. MSW

AVIATION

(18Z TAFS) Issued at 1229 PM CDT Tue May 26 2026

VFR conditions prevail at all area airports. TEMPO groups are in effect for all area airports this afternoon/evening and again tomorrow afternoon/evening for shower and storm activity across the area, which will drop conditions to MVFR. Wind shifts greater than 30 degrees will be expected throughout the forecast period. MSW

MARINE

Issued at 1229 PM CDT Tue May 26 2026

High pressure anchored over the western Atlantic will maintain light to moderate onshore flow across the local coastal waters. Daily showers and storms will be capable of producing locally hazardous winds and seas, with a few cells each day capable of producing winds in excess of 34 kts over the next few days.

LIX WATCHES/WARNINGS/ADVISORIES

LA...Flood Watch until 7 PM CDT this evening for LAZ039-064-070- 076>080-087-089>093-098>100.

GM...None. MS...Flood Watch until 7 PM CDT this evening for MSZ077-083>088.

GM...None.