textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 524 AM CST Mon Dec 1 2025 - A surface low will approach the area today from the southwest, spreading light to moderate rain across the area. Best timing will be from late morning through around daybreak Tuesday. Area averaged rainfall totals of 0.5-1.5" can be expected, but could see a band of locally greater rainfall totals of 1.5-2+" for NW or central areas.

- Much colder air filters into the region following this system, providing another freeze for areas along/north of I-10/12 Wednesday morning.

- This active pattern continues going into Thursday and Friday, with another system expected to deliver rain to the area. More details on this system will become clearer over the next few days.

SHORT TERM

(Tonight through Tuesday night) Issued at 1011 PM CST Sun Nov 30 2025

Plenty to discuss tonight as we've entered a temporary lull between two systems. The first one earlier today produced light showers for a few areas, dissipating towards the east leaving only drizzle behind and since, has turned fully dry across the entire area. Meanwhile, CAA has built into the region following a frontal passage introducing noticeably cooler air to the area. Had to play a little catchup with temperatures earlier as CAA overwhelmed the diurnal curvature late afternoon into the evening, revealing a slight reduction and has since lowered MinT's towards Monday morning towards the cooler side of guidance (blend of 75th and 50th, deterministic was above the 75th) to follow this trend.

Monday starts out cool and cloudy for all areas, while we shift our focus to the southwest at our next system. A subtle impulse crossing the Mexican plateau, coupled with an approaching positive tilt shortwave trough over the central/southern Rockies will support downstream divergence and eventual low-genisis in the western Gulf, riding this low northeast over the remnant frontal boundary during the day on Monday into Monday night. Quite the overall dynamic meteorological setup with a broad low passing generally over out coastal/marine areas, with plenty going on in the meteorological realm. Greatest/strongest 300k isentropic lift/ascent will remain confined near the low and to the east, supporting increasing shower activity spreading inland over coastal MS/AL, meanwhile, overrunning deeper curl-back of H6-H7 isentropic ascent combined with dynamic ascent will support an elevated shield of stratiform precipitation to the northwest. As mentioned for a few days now, the synoptic support for a deformation band to form remains possible somewhere from Lafayette to Hattiesburg, as the RRFS-A continues to depict and now, to a slightly lesser extent, recent HRRR runs. Going through the HREF suite shows a diverse number of solutions representing different banding intensities (NAM Nest and HRW NSSL being the most prominent along with the RRFS-A, with the recent HRRR and ARW/FV3 mix being a bit more "watered down" - no pun intended). Regardless, the more extreme members depict a very noticeable higher QPF corridor, somewhere in the 2-3" range in the corridor mentioned earlier, with more widespread 0.5-1.5" elsewhere. I'm not seeing any distinctly concerning impacts related to this potential band, as rainfall intensities in an elevated stratiform shield should be relatively moderate and over a longer duration, at best. Probably slow enough to allow the ground to soak up some of this water, which we need. We'll monitor if this band is more intense and is slow in any eastward progression (resulting in training), where flooding could occur but for now, concur with the area- wide marginal risk of excessive rainfall.

Additional notes include seeing some 100-200j/KG MUCAPE across the region, could have a rumble of thunder or two but kept the best probabilities/mention of thunder confined closer to the steepest/strongest isentropic ascent near and to the east of the low's track. Might also get a few strong to locally severe storms in the warm sector or closest to the lift associated with the low. Also, highs during the day on Monday were nudged down due to widespread cloud cover and light stratiform showers building into the region during the morning/afternoon, probably starting as virga as we've got quite the dry layer aloft between H7-H5 per the 00Z KLIX RAOB.

All rain departs early Tuesday morning to around daybreak Tuesday, becoming lighter with time and CAA/NW winds build into the region. Skies clear out as we get into the late morning/afternoon but still overall chilly with highs primarily in the 50's with a breezy NW wind.

That'll bring us to Tuesday night/Wednesday morning as the bulk of the continental polar airmass settles into the region supported by a surface high over the northern Gulf. Clear skies and calm winds will support maximized radiational cooling to bring a cold night for all areas. Guidance coming in pretty warm, above the 75th percentile and did add in a nudge down below the 75th, this brings below freezing temperatures along and north of the I-10/12 corridor, where Freeze Warnings will likely be in effect. Not reaching the Southshore yet with upper 30's to low 40's. KLG

LONG TERM

(Wednesday through Sunday night) Issued at 1011 PM CST Sun Nov 30 2025

High pressure builds east of the region during the day on Wednesday, producing a steady E to SE sfc return flow back to the area. The next system is ready to take shape over the southern US/western Gulf in a similar setup to what we'll see today - a positive tilt trough diving into the central/southern Rockies and a secondary upper-level low over Baja ejecting energy NE across the Mexican Plateau. Build WAA and dynamic ascent in the region will support yet another round of showers Thursday into Friday. Still have some questions on specifics, but will wait for as we get closer but it is looking likely we'll see another soaker Thursday and Friday. We try to see a brief dry period getting into Saturday, but it looks short-lived as long-range guidance hints at a pretty active quasi-zontal H5 pattern over the US, providing quick-hitting systems to continue. Something to monitor. KLG

AVIATION

(12Z TAFS) Issued at 524 AM CST Mon Dec 1 2025

A low pressure system and stationary front over the area will keep IFR ceilings in place through tomorrow morning. Ceilings will generally range between 500 and 800 feet. As the low strengthens later today, an area of light to moderate rain will form over all of the terminals. The rain will be heaviest generally from the late afternoon through the early overnight hours, or generally between 21z and 08z. The rain will reduce visiblities to 2 to 3 miles for several hours.

MARINE

Issued at 1011 PM CST Sun Nov 30 2025

Changes since last update: Added Small Craft Advisory for GMZ575 and 577 in effect through noon Monday. Exercise caution for all waters expect MS sound and Lake Pontchartrain/Maurepas from Noon Monday through 9PM Monday night.

New: Small Craft Advisory in effect for all waters 9PM Monday through 3PM Tuesday.

Tonight, a recent frontal passage has introduced gusty wind at around 18-22kts from the NE, which will persist overnight into Monday morning ahead of the next developing surface low over the western Gulf. As this low drifts northeast, it'll cross gulf waters providing a round of heavy rain and thunderstorms primarily from Monday afternoon through early Tuesday morning. In any one storm, waterspouts, winds <34kts and locally higher waves/seas can be expected. As this low passes, confidence on how strong winds will remain outside of thunderstorms remains in question. There is now exercise caution headlines as the low passes, but could be upgraded to advisory if conditions warrant. Then, as the low passes early Tuesday to the NE, strong NW winds will increase across waters at around 15-20kts, with the 2nd round of Advisory headlines in effect. Waves/seas will respond reaching around 5-7ft in this time frame mainly for Gulf waters, 3-5ft for protected waters. High pressure builds into the region mid-week, with winds and waves/seas calming down, but still expecting another system to impact the region Thursday and Friday, with increasing winds and shower/thunderstorm activity expected.

PRELIMINARY POINT TEMPS/POPS

MCB 53 37 49 27 / 90 100 10 0 BTR 59 39 52 29 / 90 100 10 0 ASD 64 42 55 26 / 70 100 10 0 MSY 64 47 56 40 / 70 100 10 0 GPT 64 46 57 32 / 60 100 10 0 PQL 64 46 58 27 / 60 100 20 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.