Marine Weather Net

Port Fourchon, LA to Lower Atchafalaya River, LA out 20 - 60 NM Marine Forecast


TONIGHT

S
WINDS
5 KNOTS

TUESDAY

SW
WINDS
5 KNOTS

TUESDAY NIGHT

S
WINDS
5 KNOTS

WEDNESDAY

S
WINDS
5 KNOTS

The Marine Weather Forecast In Detail:
GMZ570 Forecast Issued: 537 PM CDT Mon Jul 13 2026

Tonight...South Winds Around 5 Knots. Seas Around 2 Feet. Wave Detail: South 2 Feet At 5 Seconds. A Slight Chance Of Thunderstorms This Evening. A Chance Of Showers. A Chance Of Thunderstorms After Midnight.
Tuesday...Southwest Winds Around 5 Knots. Seas Around 2 Feet. Wave Detail: Southeast 2 Feet At 6 Seconds And Southwest 1 Foot At 4 Seconds. A Chance Of Showers And Thunderstorms.
Tuesday Night...South Winds Around 5 Knots. Seas Around 2 Feet. Wave Detail: Southeast 2 Feet At 5 Seconds.
Wednesday...South Winds Around 5 Knots. Seas Around 2 Feet. Wave Detail: Southeast 2 Feet At 6 Seconds.
Wednesday Night...Southeast Winds 5 To 10 Knots. Seas Around 2 Feet. Wave Detail: South 2 Feet At 6 Seconds.
Thursday...Southeast Winds Around 5 Knots. Seas Around 2 Feet. Wave Detail: South 2 Feet At 5 Seconds.
Thursday Night...Southeast Winds 5 To 10 Knots. Seas Around 2 Feet. Wave Detail: Southeast 2 Feet At 7 Seconds.
Friday...East Winds Around 5 Knots. Seas Around 2 Feet. Wave Detail: South 2 Feet At 6 Seconds.
Friday Night...Southwest Winds 5 To 10 Knots. Seas Around 2 Feet. Wave Detail: West 2 Feet At 3 Seconds And Southeast 1 Foot At 6 Seconds.
Saturday...Northwest Winds 5 To 10 Knots. Seas Around 2 Feet. Wave Detail: Northwest 2 Feet At 3 Seconds And Southeast 1 Foot At 6 Seconds. A Slight Chance Of Showers And Thunderstorms In The Morning.
Saturday Night...West Winds 5 To 10 Knots, Increasing To 10 To 15 Knots After Midnight. Seas 2 To 3 Feet. A Slight Chance Of Thunderstorms. A Slight Chance Of Showers In The Evening, Then A Chance Of Showers After Midnight. Winds And Seas Higher In And Near Thunderstorms.
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Area Forecast Discussion
National Weather Service New Orleans LA
107pm CDT Monday July 13 2026

.SHORT TERM... (Now through Thursday night) Issued at 1248pm CDT Monday July 13 2026

A strong (599 dm) upper ridge was centered over Minnesota this morning. A trough extended from east Tennessee into north Texas. At the surface, a stationary front was to the north of Interstate 20. A nearly solid area of rain and embedded thunderstorms was moving off the Louisiana coast, but we are seeing additional storms developing to the north of there where cloud cover is thinner.

The 12z LIX upper air sounding was extremely moist, with the precipitable water value at 2.35 inches. That's pretty close to the daily max. Moisture levels stay pretty close to the 90th percentile into Tuesday evening before some drying takes place. By Thursday, precipitable water values fall to about 1.5 inches, which is actually close to the 25th percentile at that point.

Most of the major metro areas are currently in a lull in the precipitation, but the redeveloping areas to the north will certainly have the potential to produce locally heavy rain this afternoon. While these storms will likely produce 2-3 inch/hour rainfall rates, they are moving, so that should limit any flood threat somewhat. Wind gusts should probably top out around 30-35 knots. Overall, rain amounts around an inch over the next 24-36 hours will be common, but isolated totals of 3-5 inches are possible with the stronger cells. Areal coverage of precipitation will diminish each day, with the forecast completely dry on Thursday.

As areal coverage of precipitation decreases, the daytime temperatures will increase. We won't get out of the 80s today, and probably not tomorrow, although it'll be a few degrees warmer. Wednesday will get to around 90 and Thursday more like 90 to 95.

Long Term
(Friday through Sunday night) Issued at 1248pm CDT Monday July 13 2026

By Friday there appears to be a TUTT moving across the central/north- central Gulf and that will begin to weaken the ridge over the north- central Gulf and thus allow for a few more thunderstorms to develop. Scattered storms are then expected each afternoon through the weekend. The question for now is how far west that system gets before getting absorbed and pulled to the northeast.

As for temps we will see a return of lower to mid 90s on Thursday given far few storms and slightly warmer low level temps. Little day to day change is expected through the weekend, with the only factor making a difference is timing of convection each day. As the low level moisture starts to creep back up as well we may see a few locations push heat advisory criteria by Friday, and continue through the weekend.

Marine
Issued at 1248pm CDT Monday July 13 2026

Outside outflow boundaries from storms, a predominant southerly wind around 10 knots will remain through Wednesday. Wind direction will shift to westerly and eventually NW Thursday through the end of the week. Seas will generally be 2 to 3 feet over the open Gulf waters and 2 feet or less across the protected waters. Thunderstorms remain the primary short-duration hazard. Storms may produce frequent lightning, waterspouts, and sudden wind shifts and strong gusts with locally higher waves. Thunderstorm coverage should be greatest through tomorrow before decreasing later in the week.

NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...None. GM...None. MS...None. GM...None.