Port Fourchon, LA to Lower Atchafalaya River, LA out 20 - 60 NM Marine Forecast
| Tonight...Southwest Winds Around 5 Knots, Becoming South Around 5 Knots After Midnight. Seas 1 Foot Or Less. Wave Detail: Southwest 1 Foot At 5 Seconds. |
| Sunday...South Winds Around 5 Knots, Becoming Northeast Around 5 Knots In The Afternoon. Seas 1 Foot Or Less. Wave Detail: South 1 Foot At 5 Seconds. A Slight Chance Of Showers And Thunderstorms. |
| Sunday Night...Southeast Winds Around 5 Knots. Seas 1 Foot Or Less. Wave Detail: South 1 Foot At 5 Seconds. |
| Monday...East Winds Around 5 Knots. Seas 1 Foot Or Less. Wave Detail: South 1 Foot At 5 Seconds. A Slight Chance Of Thunderstorms In The Morning. A Slight Chance Of Showers. |
| Monday Night...Southeast Winds Around 5 Knots. Seas 1 Foot Or Less. Wave Detail: Southeast 1 Foot At 5 Seconds. |
| Tuesday...Northeast Winds 5 To 10 Knots. Seas 1 Foot Or Less, Then Around 2 Feet In The Afternoon. Wave Detail: Northeast 1 Foot At 2 Seconds And South 1 Foot At 6 Seconds, Becoming Northeast 1 Foot At 3 Seconds And South 1 Foot At 5 Seconds. |
| Tuesday Night...East Winds 10 To 15 Knots With Gusts Up To 20 Knots. Seas 2 To 3 Feet. Wave Detail: Southeast 3 Feet At 5 Seconds. A Slight Chance Of Showers And Thunderstorms After Midnight. |
| Wednesday...East Winds 15 To 20 Knots, Increasing To 20 To 25 Knots In The Afternoon. Seas 3 To 4 Feet, Occasionally To 5 Feet, Building To 5 To 7 Feet, Occasionally To 9 Feet In The Afternoon. Wave Detail: East 4 Feet At 5 Seconds, Becoming East 5 Feet At 5 Seconds. A Chance Of Showers And Thunderstorms. |
| Wednesday Night...East Winds 20 To 25 Knots. Seas 8 To 11 Feet, Occasionally To 14 Feet. Wave Detail: East 9 Feet At 8 Seconds. A Chance Of Showers With A Slight Chance Of Thunderstorms In The Evening, Then A Slight Chance Of Showers After Midnight. |
| Thursday...East Winds 20 To 25 Knots. Seas 6 To 8 Feet, Occasionally To 10 Feet. Wave Detail: East 8 Feet At 8 Seconds. A Chance Of Showers. A Slight Chance Of Thunderstorms In The Afternoon. |
| Thursday Night...East Winds 20 To 25 Knots, Diminishing To 15 To 20 Knots After Midnight. Seas 7 To 9 Feet, Occasionally To 11 Feet, Subsiding To 5 To 8 Feet, Occasionally To 10 Feet After Midnight. A Chance Of Showers. A Slight Chance Of Thunderstorms After Midnight. Winds And Seas Higher In And Near Thunderstorms. |
| Area Forecast Discussion National Weather Service New Orleans LA 632pm CDT Sat September 12 2026 .SHORT TERM... (Now through Sunday) Issued at 134pm CDT Sat September 12 2026 A weak mid-level shortwave will continue to move slowly through the Lower Mississippi Valley today. The environment across the forecast area varies from less to more convectively favorably. satellite imagery currently shows quite dry mid level air moving in from the northwest. TPW Satellite Blended PW reflects this as well, though its not as evident due to high low level moisture in place. Regardless, PW values (Precipitable Water values) generally ranging from around 1.7 inches inland to over 2 inches closer to the coastal areas of LA and MS. Current shower/storm activity thus is pretty much where you'd expect it to be or not be...less over northern half of the CWA (County Warning Area) and more to the south. Heavy rain will remain the primary concern with any more persistent convection. Deeper moisture and relatively weak steering flow will support efficient rainfall processes, and localized rates of 1 to 3 inches per hour will be possible in the strongest cells. Most locations will not see amounts anywhere near that high, but repeated development along remnant outflow boundaries or other mesoscale convergence zones could quickly produce several inches in a small area. Convection should gradually diminish this evening with the loss of daytime heating. That shortwave begins pulling farther east Sunday which will cause heigheights to rise from the west and the Southern Plains upper ridge begins expanding toward the region. This should mark the start of a transition toward a more typical late-summer convective pattern, with storms increasingly tied to the sea breeze, differential heating, and leftover outflow boundaries. Rain chances will decrease from Saturday but will not disappear with the area still on the eastern periphery of the ridge. Increasing sunshine should also allow temperatures to begin trending upward with highs in the lower to possibly mid 90s. Long Term (Monday through Friday night) Issued at 134pm CDT Sat September 12 2026 The upper ridge becomes established across the Tennessee Valley/northern Alabama region Monday and should remain the dominant feature through at least the middle of the week. Increasing subsidence beneath the ridge will result in a noticeable reduction in convective coverage compared with the weekend, although enough boundary-layer moisture should remain for isolated to scattered afternoon storms along the sea breeze and other mesoscale boundaries. Monday should begin the warmer portion of the forecast with highs generally in the lower to middle 90s. Tuesday and Wednesday currently appear to be the hottest and relatively driest days as the 596-598DM ridge remains strongest overhead or just to the north. Afternoon highs in the lower to middle 90s combined with dewpoints generally in the lower to middle 70s should yield heat indices largely in the 100 to 107 degree range. Thats mostly below the 108 degree Heat Advisory criteria, but there's not much room to spare. A few localized locations could reach just above 108, particularly Tuesday, if temperatures reach the warmer end of guidance while dewpoints remain elevated. Conversely, greater mixing or an isolated afternoon storm would knock apparent temperatures down quickly. Warm overnight lows in the middle 70s inland and upper 70s around the urban/coastal corridor will also provide only modest overnight relief. Strong subsidence from that ridge will really stunt POPs as well during this timeframe. Pattern change looks to then be coming Thursday. Global models continue to favor some weakening of the portion of the upper ridge aloft as an inverted trough or an upper low approaches from the Florida/western Atlantic region. This would allow deeper moisture to begin returning, with an increase in afternoon shower and thunderstorm coverage and a corresponding easing of daytime temperatures. One interesting feature to watch with this synoptic evolution is dry slot on the northwestern side of the upper low coming across the Gulf. Models suggest it may be pulling in dry air caught underneath the ridge into the CWA, effectively keeping rain chances down quite a bit inland with most of the convection along the coast and in the open Gulf waters. Marine Issued at 134pm CDT Sat September 12 2026 Winds are gradually turning more south-southwesterly with the Bermuda ridge centered east of the area and building west across the Gulf. Wind speeds should be light at 10 knots or less as the pressure gradient is quite weak. A smaller scale ridge of high pressure will develop more centered over the north-central Gulf next week. This will cause winds to become even lighter and variable at times. With those light winds, waves/seas will generally remain in the 2 feet or less range. Additionally, thunderstorm activity will develop each day, peaking in the early to mid-morning hours, and these storms will produce higher wind gusts, waterspouts, and lightning concerns. NOAA New Orleans LA Office: Watches - Warnings - Advisories LA...None. GM...None. MS...None. GM...None. |
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