textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 1115 AM CDT Sat Sep 19 2026

- Generally dry and hot conditions will persist through the weekend.

- Rain chances will gradually increase early next week.

SHORT TERM

(Now through Tuesday) Issued at 1115 AM CDT Sat Sep 19 2026

A strong upper ridge remains centered over northeast Texas while a weak upper low continues to move westward across Florida toward the eastern Gulf. At the surface, high pressure remains nearby with clear skies and generally light or calm winds across the area. The upper low will make little westward progress toward the local area today as the ridge remains firmly in control, maintaining strong subsidence and a very dry column above the boundary layer. As a result, today will be another mostly sunny and hot day with essentially no meaningful rain chances. Highs should reach the lower 90 to mid 90s, with a few locations around Baton Rouge metro and southwest Mississippi approaching the upper 90s. These values are several degrees above normal and near daily records at a few locations, although most sites should remain just below record levels. Increasing low-level moisture compared to Friday will also push afternoon heat indices back toward or above 100 degrees in more areas than not, but values should remain below Heat Advisory criteria.

Basically no changes through Sunday as the ridge continues to provide the dominant influence over the region. However, the surface ridge shifting closer to the northern Gulf Coast will allow low- level moisture to gradually increase. This will be most noticeable in dewpoints and heat indices. Highs again will soar into the mid 90s across much of the CWA and peak heat indices top out generally in the 100 to 106 degree range. A few localized spots could briefly approach the 108 degree Heat Advisory threshold, but currently looks like insufficient coverage and duration for a headline. Rain chances will remain very low across most of the area. The exception may be the Mississippi coast and adjacent waters where enough moisture may reach the western periphery of the eastern Gulf upper low to support a very isolated afternoon shower or thunderstorm.

The first more noticeable change in the forecast arrives Monday as a northern-stream shortwave tracks across the northern Plains toward the upper Mississippi Valley. Doing this helps flatten/weaken the northern and eastern side of the upper ridge aloft. At the same time, continued low-level moisture return and decreasing subsidence should allow a more substantial recovery in column moisture. This should be enough to bring back a more typical late-summer diurnal convective pattern, although coverage still looks fairly limited. Expect isolated to scattered showers and thunderstorms to develop first near the coast along seabreeze boundaries before spreading inland during the afternoon. Coverage should generally remain highest across the coastal half of southeast Louisiana and southern Mississippi, with lower chances farther northwest toward Baton Rouge and southwest Mississippi. Temperatures Monday will remain well above normal, with highs generally in the lower to mid 90s before convection develops. Heat indices may again reach the lower to middle 100s and could briefly approach advisory criteria in a few locations if convection is delayed. Any showers or storms would quickly interrupt the heat, making duration and areal coverage the main limiting factors for a heat headline. Organized severe weather is not currently indicated. Locally heavy downpours will be possible with individual storms, but limited convective coverage and the absence of a focused low-level boundary should keep any training or flooding concern quite low.

MEFFER

LONG TERM

(Tuesday night through Friday) Issued at 1115 AM CDT Sat Sep 19 2026

The trend in the extended forecast has shifted back toward a warmer and drier solution. By Tuesday, the northern-stream shortwave will be moving toward the Great Lakes while the weakening upper low in the eastern Gulf begins to lift northeastward. Rather than allowing a deeper trough to become established over the eastern CONUS, the upper ridge is now expected to rebuild eastward from Texas and the southern Plains. There could still be enough residual moisture and weak daytime convergence Tuesday for an isolated afternoon shower or storm, particularly closer to the coast, but the rebuilding ridge should increasingly suppress convection from Tuesday into Wednesday. That trend looks to continue the remainder of the forecast period and end of next week as ridging remains the dominant feature aloft. The best moisture and instability should become confined to the coastal waters with mainly dry conditions across most land areas. The persistence of the ridge will also keep temperatures above late- September normals. Highs should remain mainly in the lower to middle 90s Tuesday and Wednesday. A gradually increasing northeasterly low- level component may trim temperatures by a few degrees Thursday and Friday, but no meaningful cool-down is currently expected. Overnight lows will generally remain in the lower to middle 70s inland and middle to upper 70s near the coast and tidal lakes as warm water augments temps.

MEFFER

AVIATION

(18Z TAFS) Issued at 1115 AM CDT Sat Sep 19 2026

VFR conditions are expected to prevail through the period. Skies will remain mostly clear with only limited daytime cumulus development. Winds will be light and variable early this morning, becoming generally easterly to southeasterly during the afternoon at less than 10 knots before becoming light again tonight. No precipitation or significant ceiling/visibility restrictions are expected at the terminals through the current TAF period.

MEFFER

MARINE

Issued at 1115 AM CDT Sat Sep 19 2026

Benign marine conditions are expected through the weekend as a broad surface ridge extending across the Southeast continues to settle southward toward the northern Gulf Coast. As the ridge moves closer, the pressure gradient will relax further and winds will remain generally light, gradually becoming more onshore. Rain chances remain very low today due to strong ridge induced subsidence, with only isolated convection possible near the Mississippi coastal waters Sunday. Shower and thunderstorm coverage should increase somewhat Monday as moisture returns and upper-level subsidence weakens. Any thunderstorm could produce locally higher winds and seas, but widespread marine hazards are not anticipated. Surface high pressure should remain close enough to the northern Gulf Coast through much of next week to maintain a relatively weak gradient. A somewhat more persistent northeast to east flow may develop by the middle to latter part of the week as high pressure builds to the north.

MEFFER

LIX WATCHES/WARNINGS/ADVISORIES

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