textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 1219 AM CST Tue Dec 2 2025 - 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 2-6 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

(Today through Wednesday) Issued at 1219 AM CST Tue Dec 2 2025

It has been a dreary night across much of the area. A band of moderate to even heavy rain impacted the southeastern 3rd/half of the CWA with some locations near the New Orleans metro and across portions of the eastern 2/3rds of coastal MS seeing around 2 to 3 inches of rain. Through 4z it was a rather sharp cutoff from moderate rain to much lighter/lower amounts with MSY only seeing 0.21" NEW around 0.6" and NBG around 2.89". While ASD had 0.27" GPT with 3.23" and PQL 2.31". All areas back to the west mainly saw a few hundredths to 0.2". Spotty showers will continue through the night with final clearing line stretching from northeast to southwest near Monroe to Natchitoches to just east of Houston. That should move east and into northwestern portion of the CWA between 10 and 11z and clearing at least half of the area by 16z.

The greatest concern over the next 24-36 hours will be the possibility of freezing temps tonight. A broad area of low pressure just off the southeast LA coast is the main culprit with respect to the rain. It will quickly lift to the northeast and will be along the Atlantic coast of NC and VA. The main driver is the broad L/W trough which is running SSW from Ontario through the Mid MS Valley and about half way through the southern Plains. The pattern flattens out pretty quickly across TX with generally westerly from the Pacific across Mexico, Texas, the Gulf and much of the Gulf coast states. The trough really de-amplifies with little to no noticeable trough passage over our area as it moves east with mid lvl flow remaining out of the west. Today we will begin the day overcast over much of the area. The back edge of the last few showers will begin to move in around 10/11z and should be completely through the area around 19/20z with the clearing line behind that. Breezy northerly winds, CAA, and mostly cloudy conditions through a good chunk of the day will keep the area on the chillier side with highs only climbing into the upper 40s to near 60 (northwest to southeast). This could set the stage for a chilly night but will we be able to optimize the setup.

As mentioned earlier we don't really get a trough axis to pass through the area and with westerly flow there is no real support to push a much colder drier airmass down into the area and this is making the forecast for tonight a little tricky. High pressure will build in and should be sitting right over the region tonight. Skies will clear out and winds will decouple. Winds will be light even in the LL and all of that would suggest a rather favorable radiational cooling night setup but there are a number of little things that could be overlooked.

Typically I would think the NBM is once again struggling with a warm bias as the deterministic NBM is in some locations 4 degrees warmer than the 90th percentile. However, even the ECS and MAV are more in line with the NBM. Why is the NBM sooooooo warm compared to its probabilities? I think there are multiple things. First off is the rain we have seen tonight. Yes that hasn't been a lot over much of the area but in the locations that typically get the coldest on these radiational cooling nights we have had a decent wetting rain. Second, looking up stream we don't even see dewpoints in the upper 20s till you get to northern AR and that air isn't going to surge southeast. We will likely remain cloudy through at least the first half of the day so with only a few hours or full sunlight and no real surge of drier air the sfc and skin layer will still be sufficiently moist. That will hurt radiational cooling potential. The other possible impacts which multiple models are showing is that between 00z and 12z Wed we will actually see WAA at h925. Temps at that level could rise as much as 5 degrees during that time. As much as I would like to cut temps, especially in our drainage areas, and go closer towards the NBM75 or NBM50 there are enough questions to make me hesitate and stick rather close to the latest NBM. With that we will maintain the temps of upper 20s to near freezing along and north of the 10/12 corridor but it would not be a surprise if this forecast needs to be adjusted in either direction. The overall setup would suggest cooler but all of the little hiccups suggest maybe a degree or two warmer than our current forecast.

High pressure quickly slides east with return flow back over the area late Wednesday with temperatures quickly moderating compared to this afternoon. High will be back in the upper 50s to mid 60s across the area Wednesday ahead of the next system which will begin to take shape across the southern Plains and western Gulf. /CAB/

LONG TERM

(Wednesday night through Monday) Issued at 1219 AM CST Tue Dec 2 2025

Models continue to hit at another 36 to 48 hour period of unsettled weather across the Gulf coast. A broad and positively tilted L/W trough will be in place from the central Canada/US border into the Pacific through the Baja. This will place much of the Gulf coast under WSW flow aloft with rather deep moisture being transported into the area from both the Gulf and Pacific. PWs could climb to around 1.75 to 1.9" which is right around the 10th percentile. At the sfc we will see broad low pressure begin to take shape over the western Gulf and TX coast with an inverted trough bisecting the CWA Thursday and Thursday night before finally starting to slide east Friday. This will be parallel to the WSW flow aloft which would suggest the potential for training at times. There will also be some instability to work with which would suggest embedded thunderstorms. The instability and rather high PWs would lead to more efficient rain. Looking aloft we could be loosely under the RRQ but overall the upper lvl divergence/diffluence isn't the greatest. Current Marginal ERO over the area for day 3 looks good however we could see a increase to a Slight Risk if trends continue with possible heavy rain over the area.

Sfc low eventually starts to take shape and slides east into the northwestern Gulf Friday night while the broad L/W trough pushes east across the central CONUS. High pressure quickly builds in Saturday with a dry and cool weekend expected. /CAB/

AVIATION

(06Z TAFS) Issued at 1219 AM CST Tue Dec 2 2025

Biggest concern with TAFS through the overnight/early morning hours will be cigs. The moderate to heavy rain has pushed out of the area with mainly spotty to scattered light rain/showers expected to continue through the morning hours with the area drying out from west to east. IFR and even LIFR cigs will impact all terminals between now and 15z before we begin to see improvements from west to east. CIGS will likely hover between 200-600 through 13/14z and then we will start to see some improvement with most terminals back in VFR status before 18z; GPT may still be dealing with BKN cigs around 1500 ft but these should quickly scatter out through the early afternoon hours. /CAB/

MARINE

Issued at 1219 AM CST Tue Dec 2 2025

A broad area of low pressure just south of the coast will continue to lift to the east-northeast into the Florida panhandle and then southern Georgia by late this morning. We are already seeing strong offshore winds on the back side of the surface low with winds gusts from 25 to 30 kts west of the mouth of the river. Winds will respond over the rest of the coastal waters as the surface low continues to move through and lifts out. The strong offshore winds will remain in place through midday slowly weakening throughout the afternoon as high pressure builds over the Lower Mississippi Valley. A small craft advisory is already in effect for all of the coastal waters and will remain so through midday. Winds should relax enough for it today drop off everywhere by mid/late afternoon. High pressure will quickly slide east across the southern US with light onshore flow returning Wednesday morning. The next system will quickly begin to take shape with broad low pressure over the western Gulf by Thursday and moving through the coastal waters Thursday night and early Friday. /CAB/

PRELIMINARY POINT TEMPS/POPS

MCB 48 29 59 44 / 0 0 0 70 BTR 51 32 62 48 / 0 0 0 80 ASD 55 30 61 46 / 0 0 0 60 MSY 56 41 63 53 / 0 0 0 70 GPT 57 34 59 47 / 10 0 0 50 PQL 59 29 60 43 / 10 0 0 40

LIX WATCHES/WARNINGS/ADVISORIES

LA...None. GM...Small Craft Advisory until 3 PM CST this afternoon for GMZ530- 532-534-536-538-550-552-555-557-570-572-575-577.

MS...None. GM...Small Craft Advisory until 3 PM CST this afternoon for GMZ532- 534-536-538-550-552-555-557-570-572-575-577.