textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 1158 AM CST Mon Dec 1 2025 - A Light to moderate rain will spread across the area today and continue through tonight. Most places are forecast to see between 0.5 and 1.0 inch of rain. Isolated thunderstorms could result in locally higher amounts in the 1-2 inch range.

- Much colder air will move into the region following this system, with the coldest temperatures forecast Wednesday morning. Another light freeze is forecast along/north of the I-10/12, with generally 3-7 hours of subfreezing temperatures forecast. - Another storm system will bring widespread rain and embedded thunderstorms to the area Thursday through Friday night. There will be at least a low-end threat of heavy rain with this system and two-day rainfall totals are currently forecast in the 2-3 inch range. Please check the forecast for updates in the coming days as forecast rainfall totals and associated flood threats will continue to be refined.

SHORT TERM

(This afternoon through Tuesday) Issued at 1158 AM CST Mon Dec 1 2025

Light to moderate rain and a few embedded thunderstorms is beginning to spread into northwestern portions of the area, and will continue to spread across the remainder of the area as the afternoon and evening progress. This is in response to an approaching upper level trough and developing surface low over the northern Gulf.

The surface low is forecast to remain south of local land areas, limiting the threat of severe weather as any thunderstorms will likely not be surface-based. Rainfall totals through tonight are generally forecast in the 0.5-1.5" range. However, a few thunderstorms could result in locally higher amounts. Given how dry the local area has been, not overly concerned about the threat of flash flooding. However, if a couple thunderstorms move over any given area in relatively short succession there is at least a low-end threat of heavy rain that could lead to flash flooding. This will be highly dependent on rainfall rates.

The low should be east of the local area by about midnight tonight as the upper level trough axis approaches. In the wake of this system, colder high pressure will once again move into the area beginning Tuesday, with afternoon highs struggling to reach the mid-50s.

LONG TERM

(Tuesday night through Sunday) Issued at 1158 AM CST Mon Dec 1 2025

Tuesday night will be the coldest night as the axis of the surface high pressure moves over the area. The combination of clear skies and light to calm winds will allow for efficient radiative cooling and temperatures will quickly drop after sunset. The current forecast calls for at least a couple hours of freezing temperatures for most places along/north of the I-10/12 corridor late Tuesday night into Wednesday morning. Most of these areas have already experienced two freezes this season, but we'll need to take a look to see if any of the more western areas around Baton Rouge require freeze headlines.

Wednesday itself will be a day of transition as the surface high shifts eastward and winds return to and easterly and then southeasterly direction by Wednesday night. The onshore winds will gradually bring moisture back into the area, ahead of yet another storm system.

This second storm system will begin to affect the area Thursday with a similar setup to what we're seeing today. A deformation zone will set up stretching from a cutoff low near Baja across the Gulf coast and into the middle eastern seaboard as embedded and positively tilted shortwave disturbances move through the overall longwave trough dominating the CONUS. The local area will remain in this favorable area for rain and isolated to scattered embedded thunderstorms both Thursday and Friday.

The threat of severe weather currently appears limited. There could be a brief window for stronger storms Friday during the day, but it will depend greatly on the position of the surface low and associated warm front. Currently the warm front does not look like it will move very far inland, which will keep most thunderstorms elevated. However, if the low and warm front move farther north, then the thunderstorm threat could increase as storms become more surface-based.

Regardless of the severe weather threat, this system looks like it will bring continued much-needed rain to the area. Two-day totals are currently forecast in the 2-3.5 inch range. However, any thunderstorms will be capable of producing locally heavier rain. Model forecast soundings indicate that precipitable water will have rebounded to the 1.5-1.75 inch range by Thursday morning, which is above the 90th percentile and approaching the daily maximum observed value. This means any thunderstorms will be capable of producing efficient rainfall. Wherever these thunderstorms move, the higher rainfall rates could lead to ponding and at least a low-end threat of flash flooding. The specific locations that receive the heaviest rain will depend on where these thunderstorms move and for the time being, a broad Marginal risk appears warranted to cover the heavy rain/flash flood threat Thursday into Friday.

Going into the weekend, there is uncertainty in whether the area will dry out or remain in an area of scattered showers and isolated storms as continued fast-moving disturbances move through the overall troughy pattern in the upper levels.

AVIATION

(18Z TAFS) Issued at 1158 AM CST Mon Dec 1 2025

An approaching low pressure system will bring widespread showers and a few embedded thunderstorms to the area through tonight. Ample low level moisture will result in generally IFR conditions at most terminals through Tuesday morning before conditions begin to improve as dry high pressure builds into the area.

MARINE

Issued at 1158 AM CST Mon Dec 1 2025

A Gulf low will approach the area later today, with gradient winds of 15-20 knots and widespread rain with a few embedded thunderstorms. An exercise caution headline remains in effect through this evening. In the wake of the low, winds will become north-northwesterly and will strengthen into the 20-25kt range, with seas responding accordingly. A small craft advisory remains in effect from late tonight through mid afternoon Tuesday. Winds and seas will ease late Tuesday through Wednesday as high pressure moves across the area. Another storm system will begin to affect the area Thursday, bringing another round of showers and thunderstorms through Friday night. Additional headlines may be necessary during this time frame.

PRELIMINARY POINT TEMPS/POPS

MCB 37 48 29 57 / 100 0 0 0 BTR 39 52 32 61 / 100 0 0 0 ASD 43 55 30 61 / 90 10 0 0 MSY 47 56 41 64 / 90 0 0 0 GPT 46 57 34 59 / 90 10 0 0 PQL 45 58 29 60 / 80 20 0 0

LIX WATCHES/WARNINGS/ADVISORIES

LA...None. GM...Small Craft Advisory until noon CST today for GMZ530-532-534-536- 538-550-552-555-557-570-572-575-577.

Small Craft Advisory from 9 PM this evening to 3 PM CST Tuesday for GMZ530-532-534-536-538-550-552-555-557-570-572-575-577.

MS...None. GM...Small Craft Advisory until noon CST today for GMZ532-534-536-538- 550-552-555-557-570-572-575-577.

Small Craft Advisory from 9 PM this evening to 3 PM CST Tuesday for GMZ532-534-536-538-550-552-555-557-570-572-575-577.