Marine Weather Net

Chandeleur Sound Marine Forecast


TONIGHT

W
WINDS
5 - 10
KNOTS

TUESDAY

NW
WINDS
5 - 10
KNOTS

TUESDAY NIGHT

W
WINDS
5 - 10
KNOTS

WEDNESDAY

N
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
GMZ536 Forecast Issued: 1139 AM CDT Mon Jul 14 2025

Tonight...West Winds 5 To 10 Knots, Becoming Northwest After Midnight. Waves Around 2 Feet. A Slight Chance Of Showers And Thunderstorms Late.
Tuesday...Northwest Winds 5 To 10 Knots. Waves Around 2 Feet In The Morning, Then 1 Foot Or Less. A Chance Of Showers And Thunderstorms.
Tuesday Night...West Winds 5 To 10 Knots, Becoming Northwest 10 To 15 Knots After Midnight. Waves 1 Foot Or Less, Then 2 To 3 Feet After Midnight. A Slight Chance Of Showers And Thunderstorms In The Evening, Then A Chance Of Showers And Thunderstorms After Midnight.
Wednesday...North Winds 10 To 15 Knots, Becoming East 5 To 10 Knots In The Afternoon. Waves 2 To 3 Feet In The Morning, Then 1 Foot Or Less. Showers And Thunderstorms Likely.
Wednesday Night...East Winds 5 To 10 Knots. Waves Around 2 Feet. Thunderstorms Likely. Showers.
Thursday...East Winds 10 To 15 Knots, Becoming Southeast In The Afternoon. Waves 2 To 3 Feet. Showers, Thunderstorms.
Thursday Night...South Winds 10 To 15 Knots. Waves 2 To 3 Feet. A Chance Of Thunderstorms. Showers.
Friday...Southwest Winds 10 To 15 Knots. Waves 2 To 3 Feet. Thunderstorms Likely. Showers.
Friday Night...Southwest Winds 10 To 15 Knots. Waves 2 To 3 Feet. A Chance Of Showers And Thunderstorms.
Saturday...Southwest Winds 5 To 10 Knots. Waves Around 2 Feet In The Morning, Then 1 Foot Or Less. Showers And Thunderstorms Likely, Mainly In The Morning.
Saturday Night...Southwest Winds 5 To 10 Knots. Waves Around 2 Feet In The Evening, Then 1 Foot Or Less. A Chance Of Showers And Thunderstorms After Midnight. Winds And Waves Higher In And Near Thunderstorms.
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Area Forecast Discussion
National Weather Service New Orleans LA
654am CDT Tuesday July 15 2025

Long Term
(Wednesday night through Monday) Issued at 1241am CDT Tuesday July 15 2025

Focus is obviously on the system that is currently just east of the Florida peninsula. NHC increased the odds of this developing into a tropical depression over the next 7 days to 40%. Models are still all over the place with how much this may develop but overall there is rather strong continuity with many of the medium and now tropical specific models in some semblance of a system moving into the north-central Gulf coast region. This would bring about some hazardous marine conditions, some mild coastal flooding, but the greatest concern appears to be very heavy rainfall. How much and how long the rain sticks around is unknown and likely won't be known until it is just about to start. That said the potential is there for a concern 36 to 48 hours and hopefully not longer.

Things could begin as early as Wednesday night but once the rain does start we may be in a prolonged period of rain with numerous to widespread showers and embedded thunderstorms lasting through Friday. As mentioned earlier there is already a trough of low pressure east of the FL peninsula and it is showing some slow organization both on radar and satellite. This system is expected to move across FL tomorrow and into the eastern Gulf overnight Tuesday night. As this system moves west across the northeastern and north- central Gulf if it is able to stay offshore it will have time and slightly favorable environmental conditions to organize and could eventually become a tropical cyclone. The upper level environment will be conducive with decent outflow on the west/southwest side of it and a favorable outflow setup to the north/northwest. This is not just a problem from tropical development standpoint as this is also a problem Thursday through Friday with respect to rain. This system will be accompanied by very rich moisture with PWs well above 2" if not above 2.25" for a substantial time. Combine that with very good diffluence aloft likely over an area of enhanced LL convergence and the recipe is there for very efficient rain.

A key to focusing on what area could see the heaviest rain will be the track, again the biggest determining factor with the heavy rain will be the track. Does it move faster or slower west; how far south does the system get after it leave FL; where does it start to slow down and try to pivot/turn north. This will have significant implications on where the heaviest rain falls. Immediately to the northwest of it will possibly be the first bout of moderate to heavy rain but the heaviest will most likely be to the south and southeast of the eventual track and especially as it starts to pivot/turn north. This will be the area with the strongest LL convergence with a band or two developing. After Friday night there is no strong feeling of where the remnants of this system will be or where it will go. It could continue to slide north and then around the southeastern CONUS ridge this weekend and into next week or it could get trapped with locally heavy rain still possible across the Lower MS Valley through the weekend and maybe even into the new work week. That said this is not an absolute and still a lot of unknowns at this time. If this system remains a tad farther south moving right along the coast, which would be the best case for our area, the heaviest rain will then remain out over the coastal waters.

Given the possibilities of significant impacts due to heavy rain we continue to bump up the forecast but again with the environmental conditions we could see the current forecast is still likely underdone. Widespread 2 to 5 inches of rain with locally higher amounts possibly even exceeding 10 inches are not out of the question. And that could just be through Friday night. At this time flood watches look likely and may be issued as early as overnight tonight (Tuesday night).

Continue to pay attention to the latest forecast and updates for the back half of the work week. Double check your supplies and know what to do and where to go in case flash flooding could impact you. If you live right along any of the more quick responding rivers in the area keep a very close eye on the river forecast over the next few days from the Lower MS River Forecast Center. /CAB/

Marine
Issued at 1241am CDT Tuesday July 15 2025

About another 36 to 48 hours of relatively benign conditions across the coastal waters with high pressure sliding west across the Gulf. Light winds and low seas will continue through Wednesday but heading into Wednesday night winds will begin to slowly increase in response to the disturbance moving west across the northern Gulf. Whether or not this become a tropical system won't matter as conditions will become more hazardous Thursday and through Friday. At the very least SCY headlines will be needed and hopefully that is all. /CAB/

NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...
Heat Advisory from 10am this morning to 7pm CDT this evening for LAZ034>037-039-046>048-056>060-064-065-070-071-076>090.

GM...None. MS...
Heat Advisory from 10am this morning to 7pm CDT this evening for MSZ068>071-077-083>088.

GM...None.