Marine Weather and Tide Forecast for Chalmette, LA

SHORT TERM
(Tonight through Sunday night)
Issued at 1012 PM CST Fri Dec 12 2025

The immediate concern of the short term period is the potential for dense fog across the area tonight. With more than one model showing decent probabilities overnight and the moisture and light winds making for a good environment, a Dense Fog Advisory has been issued for the entire area through 9AM Saturday.

Weak high pressure at the surface will start to break down heading into the weekend as our next system approaches. In the upper levels a quick shortwave moves across the region, while a deep trough moves across the Midwest. Back at the surface a strong cold front associated with the Midwestern trough will creep down towards our area, likely making it through the coast by Sunday afternoon. We will already start to see the effects of this cold front in the Sunday high temperatures. The MaxT's for Sunday will actually more than likely happen in the morning rather than the afternoon because the front will already be pushing through most areas during the "normal" daytime high time. By afternoon we start to see temperatures rapidly decrease across the area, into the 30s by late evening. In terms of precipitation, the best chance for rain is looking to be late Saturday night into early Sunday with most areas seeing a 50-60% chance of rain, but far northern areas see closer to a 70-80% chance. Looking at QPF this should be a pretty light rain with most areas seeing less than a half inch of rain.

The main threat of the short term comes Sunday night into early Monday with the cold air rushing in. MinTs are sitting in the low to mid 20s for everywhere north of the lake and the low 30s south of the lake. On top of the air temperature being cold, we will also have breezy winds gusting 15-20mph overnight which brings Wind Chills into the teens for northern areas and the low to mid 20s for southern areas. Made some adjustments to the drainage areas as those tend to cool more. That being said, everything right now would be well into Cold Weather Advisory criteria and some areas along the northshore and Coastal MS would be hovering around Extreme Cold Warning criteria. Knowing this, expect cold weather headlines Monday morning but exactly which ones is still uncertain.

LONG TERM
(Monday through Friday night)
Issued at 1012 PM CST Fri Dec 12 2025

Following the cold snap early Monday morning, we warm up into the upper 40s to lower 50s for afternoon highs. After the cold front passes, we see riding start to build to our west and move its way westward. Throughout early week this ridge will move closer to the central Gulf Coast region. This helps us warm right back up after out cold spell, with Tuesday Max T's already back into the 60s for most areas and Wednesday will already be near the 70 degree mark for most.

After the rain associated with the big cold front, we don't see any notable rain chances again through the rest of the long term period. Very minor chances on Thursday, but only ~15-20%. Winds turn back onshore by Tuesday which will push some moisture back into the area and that may aid in some fog development some mornings next week.

AVIATION
(06Z TAFS)
Issued at 1012 PM CST Fri Dec 12 2025

Seeing a wide variety of conditions across the area this evening, from LIFR to VFR. Bouncing vis and ceilings are being observed mainly at MCB, BTR, and HDC. Dense fog will continue to be a concern at most terminals overnight until just after sunrise Saturday morning. After sunrise the fog should burn off and all terminals return to VFR.

MARINE
Issued at 1012 PM CST Fri Dec 12 2025 night Light onshore winds of 10 knots or less and calm seas of 2 feet or less will persist over the waters through Saturday as a broad area of high pressure remains centered over the region. A rapid change in conditions will then take place Saturday night and Sunday morning as a very strong cold front moves through. Winds will turn northerly and increase in speed to between 25 and 30 knots with higher gusts from mid day Sunday through Monday morning. There is a decent probability that headlines will be issued for the waters over this time period due to high winds and rough seas anticipated.
Another high will then quickly settle over the area on Tuesday, and this will allow winds to turn more easterly and fall back to less than 10 knots. Seas will also begin to subside as the winds decrease Monday night into Tuesday.

PRELIMINARY POINT TEMPS/POPS
MCB 53 70 45 52 / 10 30 80 10 BTR 56 74 49 57 / 10 30 60 20 ASD 53 73 50 60 / 10 20 40 10 MSY 58 75 54 62 / 10 20 30 20 GPT 56 71 51 62 / 10 20 40 20 PQL 52 72 49 60 / 10 20 40 10

LIX WATCHES/WARNINGS/ADVISORIES
LA...Dense Fog Advisory until 9 AM CST Saturday for LAZ034>037-039- 046>048-056>060-064>071-076>090.

GM...None.
MS...Dense Fog Advisory until 9 AM CST Saturday for MSZ068>071-077- 083>088.

GM...None.