Southwest Pass of the Mississippi River to Port Fourchon Louisiana Marine Forecast
| Tonight...South Winds Around 15 Knots With Gusts Up To 20 Knots, Becoming Southwest With Gusts Up To 25 Knots After Midnight, Then Becoming Northwest 25 To 30 Knots Late. Seas 2 To 4 Feet, Occasionally To 5 Feet. Wave Detail: South 4 Feet At 6 Seconds And Northwest 3 Feet At 3 Seconds. A Chance Of Showers And Thunderstorms Late This Evening. Showers With Thunderstorms Likely After Midnight. |
| Monday...North Winds 25 To 30 Knots, Diminishing To 20 To 25 Knots In The Afternoon. Seas 4 To 6 Feet, Occasionally To 8 Feet. Wave Detail: Northwest 6 Feet At 4 Seconds And Southwest 3 Feet At 6 Seconds. A Chance Of Showers With A Slight Chance Of Thunderstorms In The Morning. |
| Monday Night...North Winds 20 To 25 Knots With Gusts Up To 30 Knots. Seas 3 To 5 Feet, Occasionally To 6 Feet. Wave Detail: North 4 Feet At 5 Seconds. |
| Tuesday...North Winds 15 To 20 Knots, Becoming Northeast 10 To 15 Knots In The Afternoon. Seas 2 To 4 Feet, Occasionally To 5 Feet. Wave Detail: Northeast 4 Feet At 4 Seconds. |
| Tuesday Night...Northeast Winds 5 To 10 Knots. Seas 1 To 2 Feet. Wave Detail: Northeast 2 Feet At 3 Seconds. |
| Wednesday...East Winds 5 To 10 Knots. Seas 1 To 2 Feet. Wave Detail: East 2 Feet At 3 Seconds. |
| Wednesday Night...Southeast Winds 5 To 10 Knots. Seas 1 To 2 Feet In The Evening, Then 1 Foot Or Less. Wave Detail: East 1 Foot At 4 Seconds. |
| Thursday...East Winds Around 5 Knots, Becoming South In The Afternoon. Seas 1 Foot Or Less. Wave Detail: East 1 Foot At 5 Seconds. |
| Thursday Night...West Winds 5 To 10 Knots. Seas 1 To 2 Feet. Wave Detail: Southwest 1 Foot At 2 Seconds And Southeast 1 Foot At 5 Seconds. |
| Friday...West Winds 5 To 10 Knots. Seas 1 To 2 Feet. Wave Detail: West 1 Foot At 3 Seconds And Southeast 1 Foot At 6 Seconds. |
| Friday Night...Southwest Winds 5 To 10 Knots. Seas 1 To 2 Feet. Winds And Seas Higher In And Near Thunderstorms. |
| Area Forecast Discussion National Weather Service New Orleans LA 645pm CDT Sunday Mar 15 2026 .SHORT TERM... (This evening through Tuesday morning) Issued at 1242pm CDT Sunday Mar 15 2026 Very little change in the forecasting for the frontal system expected overnight tonight. A potent area of low pressure in the Midwest and Great Lakes states will drive a very strong cold front through the region Sunday night. An equally strong arctic high of at least 1030mb will then quickly build in behind the front on Monday. In the upper levels, an associated longwave trough will continue to dominate the eastern half of the country through the short term period, and this will keep deep layer northerly flow in place. The end result will be a colder and drier stretch of weather after the front moves through. This should be the one last shot of cold air before the first day of spring arrives over the coming weekend. However, before the front approaches, Sunday afternoon is showing up with exceptionally warm temps as strong onshore flow develops and ushers in a significantly warmer and more humid airmass by the afternoon hours. PWATs (Precipitable Waters) will quickly rise to around 1.25 inches and temperatures will end up in the low to even middle 80s. These conditions will help to prime the atmosphere in advance of the front as conditions turn fairly unstable. MLCAPE values are still expected to peak around 1500 J/KG Sunday evening in response to steepening mid-level lapse rates that could reach as high as 7.5C/km just ahead of the front. With strong low level forcing and ample positive vorticity advection and lift aloft in place, there will be little if any convective inhibition to speak of in the evening hours. As a result, a fairly stout line of thunderstorms will develop over the Arklatex and then push to the east-southeast into the region Sunday evening. This fast moving line will encounter marginally favorable shear conditions as it moves in with effective bulk shear of 30 to 40 knots and 0-1km SRH values of around 150m2/s2. Although the dynamics will be somewhat limiting, there will still be the potential for a few bowing segments and damaging wind events to occur over the northern and western portion of the CWA. Later Sunday night, all of the convectively aided high resolution guidance indicates that the initial line of convection will begin to weaken as it moves toward the Louisiana and Mississippi coasts. However, the development of another LLJ over southern Mississippi and lower Alabama will support the development of a pre-frontal trough axis that could initially develop somewhere in the vicinity of New Orleans and Gulfport. Increasing low level shear will take hold in advance of this pre-frontal trough axis with 0-1km SRH values increasing to around 200 m2/s2 and effective shear rising to 40 to 50 knots. With ample instability in place and these favorable shear parameters, a few supercells could form over extreme southeast Louisiana, the offshore waters, and the Mississippi coast during the overnight hours Sunday, generally between 2am and 5 AM. This is the area that would have the highest risk of seeing a tornado or two develop during the overnight hours, and we will need to monitor the trends to see if this pre-frontal trough continues to be shown in the guidance. The good news here is that the front will be very fast moving, expected to pass through the area in about six hours Monday will be a day of rapid clearing as very strong negative vorticty, dry air, and cold air advection take hold. Temperatures will start off in the 40s behind the front Monday morning and will only rise into the 50s. These readings are a good 20 degrees below average for this time of year. Very windy conditions are also expected on Monday in the wake of the front as the strong high builds in from the north. Winds of 25 to 30 mph with gusts over 40 mph are expected along the coast and south of the tidal lakes. Given these conditions, a wind advisory is now in effect for these areas. The other concern will be the high potential for wildfires to occur as humidity values fall below 25 percent. A Red Flag Warning has been issued for 1pm to 7pm Monday covering most of the forecast area. The colder air will continue to feed in on the back of a strong 925mb thermal trough axis Monday night, and a light freeze is anticipated for the northern half of the forecast area. The colder conditions will persist on Tuesday as a reinforcing dry frontal passage occurs in the deep layer northwest flow regime. Highs will once again only warm into the 50s and lows will cool into the 30s and lower 40s. Temperatures will be slightly warmer due to the heart of the thermal trough finally beginning to shift to the east. A light freeze may once again occur in the Pearl and Pascagoula River drainages though. Long Term (Tuesday through Saturday night) Issued at 1242pm CDT Sunday Mar 15 2026 Subsequent to the passing of the cold front and all the attendant impacts discussed elsewhere we should be seeing the weather pattern dominated by high pressure bringing pleasant weather starting with mostly clear skies and still cool temperatures for late winter. But, this will be followed by a warming pattern which will usher in a very warm first day of spring with daytime highs in the mid to upper 80s by the weekend. Rain is somewhere in the future, but right now we aren't seeing it anywhere in the forecast. Marine Issued at 1242pm CDT Sunday Mar 15 2026 Ahead of the approaching front winds will be out of the south at 10+ knots. Then with the approach, arrival, and passage winds will increase to 30-35kt gusting higher and become northerly before dropping back to the 15 to 20kt range. Associated with the winds are Small Craft Advisories bookending a Gale Warning. Along with the high winds are seas on the order of 12ft. These hazardous conditions will last through Tuesday morning before calming through the day on Tuesday. Later in the week, high pressure dominates the weather pattern bringing more benign winds and seas. NOAA New Orleans LA Office: Watches - Warnings - Advisories LA...Red Flag Warning from 1pm to 7pm CDT Monday for LAZ034>037-039- 046>048-056>060-065>067-071-076-079>086. Freeze Watch from Monday evening through Tuesday morning for LAZ034>037-039-047-048-071-076-079>084. Wind Advisory from 4am to 7pm CDT Monday for LAZ056>060- 064>070-076>078-080-082-084-086>090. GM...Small Craft Advisory until 4am CDT Monday for GMZ530-532-534- 536-538-550-552-555-557-570-572-575-577. Small Craft Advisory from 7pm Monday to 7am CDT Tuesday for GMZ530-532-534-536-538-550-552-555-557-570-572-575-577. Gale Warning from 4am to 7pm CDT Monday for GMZ530-532-534-536- 538-550-552-555-557-570-572-575-577. MS...Red Flag Warning from 1pm to 7pm CDT Monday for MSZ068>071. Freeze Watch from Monday evening through Tuesday morning for MSZ068>071-077-083>088. Wind Advisory from 4am to 7pm CDT Monday for MSZ086>088. GM...Small Craft Advisory until 4am CDT Monday for GMZ532-534-536- 538-550-552-555-557-570-572-575-577. Small Craft Advisory from 7pm Monday to 7am CDT Tuesday for GMZ532-534-536-538-550-552-555-557-570-572-575-577. Gale Warning from 4am to 7pm CDT Monday for GMZ532-534-536-538- 550-552-555-557-570-572-575-577. |
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