Southwest Pass of the Mississippi River to Port Fourchon, LA 20 - 60 NM Marine Forecast
| This Afternoon...East Winds 15 To 20 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. Wave Detail: East 4 Feet At 5 Seconds. |
| Tonight...East Winds 15 To 20 Knots With Gusts Up To 25 Knots. Seas 4 To 5 Feet, Occasionally To 6 Feet. Wave Detail: East 5 Feet At 6 Seconds. |
| Wednesday...Southeast Winds 10 To 15 Knots With Gusts Up To 20 Knots. Seas 4 To 5 Feet, Occasionally To 6 Feet. Wave Detail: East 5 Feet At 7 Seconds. A Slight Chance Of Showers In The Afternoon. |
| Wednesday Night...Southeast Winds 10 To 15 Knots. Seas 4 To 5 Feet, Occasionally To 6 Feet. Wave Detail: Southeast 4 Feet At 8 Seconds. A Chance Of Showers. |
| Thursday...Southeast Winds 5 To 10 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: Southeast 4 Feet At 8 Seconds. A Chance Of Showers. |
| Thursday Night...Southeast Winds 5 To 10 Knots. Seas Around 3 Feet. Wave Detail: Southeast 3 Feet At 7 Seconds. A Chance Of Showers. A Slight Chance Of Thunderstorms After Midnight. |
| Friday...Southeast Winds 5 To 10 Knots. Seas 2 To 3 Feet. Wave Detail: Southeast 3 Feet At 7 Seconds. A Slight Chance Of Thunderstorms In The Morning. A Chance Of Showers. |
| Friday Night...East Winds 10 To 15 Knots. Seas Around 3 Feet. Wave Detail: East 3 Feet At 6 Seconds. A Chance Of Showers. |
| Saturday...Southeast Winds 10 To 15 Knots, Becoming South 15 To 20 Knots In The Afternoon. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: Southeast 4 Feet At 5 Seconds. A Chance Of Showers In The Morning, Then Showers Likely In The Afternoon. |
| Saturday Night...South Winds 15 To 20 Knots, Becoming Northwest After Midnight. Seas 3 To 4 Feet, Occasionally To 5 Feet, Building To 4 To 6 Feet, Occasionally To 8 Feet After Midnight. Wave Detail: South 4 Feet At 5 Seconds, Becoming Northwest 5 Feet At 5 Seconds And Southeast 3 Feet At 6 Seconds. Showers. Winds And Seas Higher In And Near Thunderstorms. |
| Area Forecast Discussion National Weather Service New Orleans LA 114pm CST Tuesday Jan 20 2026 .SHORT TERM... (This evening through Thursday night) Issued at 1201pm CST Tuesday Jan 20 2026 Overall, a warmer and wetter stretch of weather will take place in the short term period. This pattern shift will be driven by a vigorous shortwave trough passing through the region Wednesday into Wednesday night and a surface high pressure system shifting to the east allowing for an onshore flow to develop in the low levels. The shortwave feature and an associated 120 knot jet will be embedded within a broader zonal flow regime that will be in place through Thursday night in the mid and upper levels. Additionally, as the jet pushes to the east, the region will find itself beneath the right entrance region of the jet Wednesday afternoon into Wednesday night. The combination of the shortwave and jet will induce a broad area of enhanced upper level forcing across the Gulf South. The only other ingredient needed will be available moisture to tap into, and that problem will be solved as the onshore flow persists. As Gulf moisture feeds into the area, moisture will deepen from the upper levels into the low levels and PWATs (Precipitable Waters) will rise to over an inch by Wednesday afternoon. Light to moderate scattered showers will start to develop over the western half of the forecast area tomorrow afternoon and then become more numerous across the entire region by tomorrow night. The increase in dewpoints and advection of warmer Gulf air will allow temperatures to rise dramatically. Highs will climb into the mid to upper 60s and lows will climb from the 40s tonight into the 50s tomorrow night. Thursday into Thursday night will see slightly lower rain chances as a brief increase in negative vorticity advection and subsidence in the upper levels takes hold in the wake of the departing shortwave trough and jet streak. However, the low levels below 10k feet will remain very moist, and this will keep PWATs (Precipitable Waters) elevated near an inch. Temperatures will be well above average as southeast flow off the Gulf continues and the subsidence aloft both help to warm the overall atmosphere. Highs will easily rise into the upper 60s and lower 70s and overnight lows will only fall into the mid and upper 50s. Given the lack of decent deep layer forcing, rain chances will be lower on Thursday. At most, there will be some isolated to widely scattered low topped and light shower activity that forms as temperatures climb into the lower 70s and low level instability increases. However, a strong capping inversion around 700mb will inhibit any deeper convective activity and heavier showers from forming Thursday. The other concern as dewpoints climb into the upper 50s and lower 60s offshore will the development of sea fog as the warm and moist airmass passes over the cooler nearshore waters. This fog could push inland and impact areas along the coast and around the tidal lakes with dense fog Thursday night. Long Term (Friday through Monday night) Issued at 1201pm CST Tuesday Jan 20 2026 Significant differences between the various medium range model solutions remain in place today, and this leads to a lower confidence forecast for the upcoming weekend as any slight variations in the positioning of the freezing line or the timing of the moisture can have significant implications to the forecast. The most noted change today is that the GFS (Global Forecast System) is far slower with kicking the trough axis through the region with the latest run due to a northern stream vort lobe sliding down the Front Range and deepening a low over the Southern Plains Sunday night into Monday. This latest solution keeps moisture over the region through Monday night before clearing out on Tuesday. This is a large outlier from the previous runs and from the more run to run consistent ECMWF and Canadian solutions which still have the longwave trough axis sweeping through Sunday night. This clears out the moisture by Sunday evening with the primary wintry precipitation threat being confined to Saturday night and Sunday morning. The NBM solution favors the the ECMWF (European Centre for Medium-Range Weather Forecasts) and have opted to keep using the deterministic NBM output as the model source for the local forecast. Given this, Friday will start off as continued warm and moist day with highs climbing back into the 60s and lower 70s. A backdoor cold front will push in from the north and northeast in the afternoon hours and will help spark off some additional scattered light and shallow topped showers as it stalls over the area Friday evening. Isentropic lift over the cooler air to the north of the boundary during the overnight hours on Friday will allow for a persistent light rain to form in southwest Mississippi. The temperature gradient will be very sharp over the area with lows ranging from the upper 30s and lower 40s north and west of a McComb to Baton Rouge line to the lower 50s in coastal Louisiana. Saturday, temperatures will initially warm into the upper 50s and lower 60s southeast of the stalled frontal boundary and the mid to upper 40s northwest of the boundary, but a secondary front will surge in Saturday afternoon and overtake this initial boundary. This second front will push to the coast and stall by Saturday night, but the cold pool(a region of relatively cold air) behind the front will still surge southward into the area. Temperatures will start to fall Saturday afternoon and will eventually dip into the 20s and lower 30s by late Saturday night along a line extending roughly from Baton Rouge to Hammond to Bogalusa. This cold pool(a region of relatively cold air) will be very shallow and continued southwesterly flow above this cold pool(a region of relatively cold air) will produce a very deep warm layer. The end result, is that conditions are very favorable for freezing rain to impact areas north of the aforementioned line. Below this line, only a cold rain is expected. Temperatures are expected to rise a bit on Sunday even as the light to moderate overrunning precipitation event continues, but highs will barely pull above freezing in southwest Mississippi and parts of southeast Louisiana to the northwest of Baton Rouge. The rest of the area will remain well above freezing and the cold rain will continue until the moisture axis starts to quickly shift to the east Sunday evening. There may be a brief window of some light freezing rain redeveloping before the moisture fully departs on the Northshore Sunday evening, but accumulation should be very low. The rainfall rates could be moderate at times, and ice accumulations on surfaces could approach or even exceed one quarter of an inch in portions of southwest Mississippi including McComb and ville. In the adjacent areas of Louisiana, the duration of the below freezing temperatures will be less, but ice accumulations of one tenth of one quarter of an inch could still impact areas around Kentwood, Clinton, St. Francisville, and New Roads by Sunday morning. Probabilities of seeing greater than a hundredth of an inch of ice, or what is usually referred to as a light glaze, have increased to 40 to 70 percent for these areas with values of 10 to 30 percent closer to the I-12 corridor in southeast Louisiana. Additionally, probabilities of at least one quarter inch of ice accumulation on flat surfaces have risen to 20 to 40 percent for locations in in southwest Mississippi today. What this means is that overall confidence in a freezing rain event impacting the northern third of the forecast area has continued to increase. Now is the time to beginning preparing for this ice event as roads will become hazardous for travel by Saturday evening. In southwest Mississippi, people should also begin to prepare for power outages if one tenth to one quarter inch of ice accumulation occurs. Temperatures will remain well below average on Monday as a 925mb thermal trough lingers over the region on the back of persistent northerly flow. Lows will start off below freezing across the area, and will likely need some cold weather advisory products for Sunday night and Monday night as temperatures fall below freezing across the entire forecast area. Highs will struggle to climb into the upper 30s and lower 40s on Monday. Marine Issued at 1201pm CST Tuesday Jan 20 2026 Winds will remain between 15 and 20 knots through tomorrow morning in the wake of a reinforcing front that pushed through the waters overnight. Afterwards on Wednesday, winds will turn onshore at 10 to 15 knots as a high shifts to the east and a low pressure system approaches from the west. These lighter onshore winds will persist through Thursday night. Friday will see winds turn more east and northeasterly behind the departing low. Saturday should see winds increase further to at least exercise caution and possibly small craft advisory range as a reinforcing front passes through the waters and a colder airmass begins to move in from the north. By Saturday night and Sunday, winds will increase further and a period of 20 to 25 knot winds, rough seas, and small craft advisory conditions will be in place through Monday. NOAA New Orleans LA Office: Watches - Warnings - Advisories LA...None. GM...None. MS...None. GM...None. |
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