textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 518 AM CST Sun Nov 30 2025 - A front will sweep across the area today, bringing periods of showers mainly this morning, with best chances along/west of I-55. Showers steadily dissipate to the east this afternoon.

- This front stalls in the northern Gulf, then a developing surface low on this front drifts northeast bringing more widespread showers to the area Monday afternoon & night. Rainfall totals of 1-2 inches is expected, with locally higher amounts.

- This system departs early Tuesday, with much colder air filtering into the region. Another freeze is likely for areas along/north of I-10/12 Wednesday morning.

SHORT TERM

(Tonight through Tuesday) Issued at 1031 PM CST Sat Nov 29 2025

Starting things off with what's going on outside the front door tonight, KHDC radar continues to show light echoes/returns across SE MS. Earlier today, this activity helped to produce a few areas of light rain and drizzle across SW MS/Florida parishes in association with a patch of H7 mid-level and subtle PVA along progressive/quasi-zontal mid-level flow aloft. 00Z KLIX RAOB illustrates this moist layer well, sandwiched between two relatively strong subsidence inversions.

Zooming out a bit to get a grand view of the current situation shows a cold front approaching the area to our northwest. This is associated with a bigger weather maker up north causing snow for the Midwest. Expecting to see steady low-level moistening persist ahead of this frontal boundary as indicated by SE winds helping to pull (some) moisture north, just not alot as the residual airmass over the northern Gulf was left from the continental polar airmass that settled behind our last front, which has since only modified slightly over Gulf waters with dewpoints in the 50's to approaching 60. Still, enough frontogenetic lift in association with this modest available moisture will support a band of showers to approach the area from the west around daybreak, as just about all CAM's continue to suggest. Not expecting a major impact out of this, but will be enough to modify the column over time (starting out as Virga, then evaporative cooling will get any elevated echoes we'll see on radar to the ground with time). But it'll eventually lose the battle against the dry air later today and should see showers dissipate with time going into the afternoon. Still one of those days off/on light showers/drizzle can be expected, but not anticipating any impacts out of this.

Otherwise, the front will slow to a crawl over the northern Gulf and becomes more in alignment with low/mid- level quasi-zonal flow, basically losing it's push as the parent low exits into the NE US. Did target a lower approach at highs today given increasing cloud cover. Am aware the front's speed will determine which areas may top out more mild versus northern/northwestern areas that'll see the frontal passage earlier, halting temperatures from climbing much from the lows this morning. But regardless of the front's speed, clouds will slow temperatures from warming too much but could still top in the 60's to low 70's along coastal SE LA and MS, but did drop this down some from the deterministic NBM. We'll see if this was a good approach.

We'll reach a brief period of dry weather Sunday night into Monday, however will remain cloudy as moisture continues to ride over the front advecting from the WSW over the Mexican plateau. Post frontal air will try to settle in making it chilly overall, with lows in the 40's to 50's daybreak Monday.

It'll be during the day on Monday when we'll be monitoring low- genesis along the remnant stalled boundary over the W or NW Gulf, providing our next round of more widespread showers to the region. For now, most of Monday morning should be mainly dry but that'll quickly change going into the afternoon/evening hours as a rain shield builds in from the southwest over time. Now, the details associated with this low get's pretty interesting in this time frame, and all is highly reliant on just how "strong/deep" this low becomes. As the low approaches the area, likely somewhere either inland SE LA/coastal MS or just offshore, we'll see the greatest/maximized 300k moisture transport blossom across coastal marine waters, accelerating north into coastal MS/AL indicating the strongest zone of low-level isentropic upglide/ascent in association with the eastern extent of the low. Meanwhile, a few (more reliable) CAM's including the HRRR and RRFS-A indicate what has been discussed for a few days, the potential for a mesoscale deformation band NW of the surface low. It's unclear to what degree this band will cause issues with, perhaps a zone of higher QPF somewhere from near Lafayette, to Hattiesburg. Diving deeper, GFS deformation parameters flag a maximized zone in this corridor from H6 to H7, indicative of the front end of more elevated isentropic upglide banding and attendant confluence meaning, the synoptic field "makes sense" for this to form and it's encouraging , in terms of confidence to see the CAM's starting to illustrate it. Again, impacts are unclear, but widespread QPF totals of around 1-2" is looking pretty good (and slightly lower in regards to trends) however, it's cautioned locally higher amounts could be possible depending on where/how or if any mesoscale banding forms. Did also let the mention of thunder ride with this update, as there appears some subtle/minor elevated instability in this layer aloft, producing MUCAPE in the 100-200J/kg range, enough for an occasional ruble of thunder but not a whole lot. It'll be closer to the low and to the east/south in the better low-level moisture and available lift/shear where we could see some locally strong to severe storms, perhaps getting pretty close to Plaquemines parish again - depending on the exact low placement. This activity should remain mainly offshore but will closely monitor.

Once this low departs to our northeast, the rain will exit the area before/around daybreak Tuesday with CAA building into the region. Tuesday is looking chilly with breezy NW winds and clearing skies, likely seeing sunshine atleast by the late morning to afternoon hours. KLG

LONG TERM

(Tuesday night through Saturday night) Issued at 1031 PM CST Sat Nov 29 2025

By Tuesday night/Wednesday morning, the bulk of the continental polar airmass settles in nicely across the region, with ~1025mb high building into the TN valley region. It's looking cold, with temperatures likely reaching below freezing for the northern 1/3 of the area. The deterministic 01Z NBM is coming in warmer compared to the ensemble suite, and did nudge lows down slightly as we'll likely decouple from mixing and winds die down, promoting maximized radiational cooling processes. This brings freezing temperatures to right at the I-10/12 corridor on north, with upper 20's across SW MS and traditionally colder Pearl River/Pascagoula drainage basins.

As the high shifts east Wednesday, return flow will steadily build back into the region. But, that means our next system will take shape over the SW US, as a west-coast trough dives south into the four-corners region, phasing up with a cut-off low over the Baja region, accelerating moisture/PVA east promoting yet another surface low to develop over the southern US/NW Gulf. Details this far out remains to be seen, with some slight indifference in guidance, however, is enough to confidently say we'll in some way see rain later next week (Thursday & Friday time frame) but stay tuned as we unveil more details as we get closer. KLG

AVIATION

(12Z TAFS) Issued at 518 AM CST Sun Nov 30 2025

Vis and cigs will lower through the day as SHRA set in. Levels should be in and around IFR but will bounce in and out of LIFR to IFR to MVFR with light to mod rainfall. SHRA will break up a bit after noon today with only -SHRA affecting any given terminal thorugh the night while keeping flight levels in and around IFR.

MARINE

Issued at 1031 PM CST Sat Nov 29 2025

A front will approach coastal/nearshore waters today and come to a slowdown and eventually stall introducing intermittent light showers, with better chances along the immediate coast. Winds will shift out of the north behind the front with winds picking up in the 10-15kt range later this afternoon/evening to 15-20kts overnight Sunday into Monday, mainly across the Tidal Lakes, nearshore sounds/gulf waters and southwest into waters west of the mouth of the MS. A Small Craft Advisory is now in effect for these areas through noon Monday. It is highly cautioned that the eventual strength of the low will determine the potential for stronger winds to persist beyond thru early Tuesday, leading to the possibility of the Small Craft Advisory to be extended in time, though confidence for now remains low. The main impacts will be periods of heavy rain, and some strong to potentially severe thunderstorms producing winds >34 knots, locally enhanced waves/seas and waterspouts. Once the low approaches land over coastal MS/AL, a front will sweep across the area allowing winds to shift out of the NW and waves/seas increase steadily to around 5-7ft for offshore Gulf zones thru Tuesday, where additional headlines could likely be required. High pressure settles in mid-week calming down winds and waves/seas, however, confidence is increasing that we'll see another system approach Gulf waters later in the week with another increase in winds and shower/storm activity. KLG

PRELIMINARY POINT TEMPS/POPS

MCB 56 42 55 40 / 90 40 70 90 BTR 61 45 58 43 / 80 40 70 90 ASD 68 46 64 43 / 50 20 60 90 MSY 70 53 66 50 / 50 20 60 90 GPT 69 50 66 47 / 40 20 50 90 PQL 71 48 67 46 / 40 20 50 90

LIX WATCHES/WARNINGS/ADVISORIES

LA...None. GM...Small Craft Advisory from 6 PM this evening to noon CST Monday for GMZ530-532-534-536-538-550-552-555-557-570-572.

MS...None. GM...Small Craft Advisory from 6 PM this evening to noon CST Monday for GMZ532-534-536-538-550-552-555-557-570-572.