Marine Weather Net

Southwest Pass of the Mississippi River to Port Fourchon, LA 20 - 60 NM Marine Forecast


TONIGHT

N
WINDS
10 - 15
KNOTS

FRIDAY

N
WINDS
5 - 10
KNOTS

FRIDAY NIGHT

NE
WINDS
5 - 10
KNOTS

SATURDAY

E
WINDS
5 KNOTS

The Marine Weather Forecast In Detail:
GMZ572 Forecast Issued: 705 PM CDT Thu Oct 30 2025

SMALL CRAFT ADVISORY IN EFFECT UNTIL 10 PM CDT THIS EVENING
Tonight...North Winds 10 To 15 Knots. Seas 3 To 5 Feet, Occasionally To 6 Feet. Wave Detail: Northwest 4 Feet At 6 Seconds And Northeast 3 Feet At 5 Seconds.
Friday...North Winds 5 To 10 Knots. Seas 2 To 3 Feet. Wave Detail: West 2 Feet At 6 Seconds.
Friday Night...Northeast Winds 5 To 10 Knots. Seas Around 2 Feet In The Evening, Then 1 Foot Or Less. Wave Detail: West 1 Foot At 5 Seconds, Becoming Northeast 1 Foot At 4 Seconds And West 1 Foot At 5 Seconds.
Saturday...East Winds Around 5 Knots. Seas 1 Foot Or Less. Wave Detail: West 1 Foot At 5 Seconds.
Saturday Night...East Winds 5 To 10 Knots, Becoming Northeast 10 To 15 Knots With Gusts Up To 20 Knots After Midnight. Seas 1 Foot Or Less, Then Around 2 Feet After Midnight. Wave Detail: East 1 Foot At 3 Seconds, Becoming Northeast 2 Feet At 3 Seconds. A Chance Of Showers In The Evening, Then Showers Likely With A Slight Chance Of Thunderstorms After Midnight.
Sunday...North Winds 15 To 20 Knots With Gusts Up To 25 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. Wave Detail: North 3 Feet At 5 Seconds. A Chance Of Showers With A Slight Chance Of Thunderstorms In The Morning, Then A Slight Chance Of Showers In The Afternoon.
Sunday Night...North Winds 15 To 20 Knots With Gusts Up To 25 Knots. Seas 3 To 5 Feet, Occasionally To 6 Feet. Wave Detail: Northeast 4 Feet At 5 Seconds. A Slight Chance Of Showers In The Evening.
Monday...North Winds 15 To 20 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: North 3 Feet At 5 Seconds.
Monday Night...North Winds 15 To 20 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: North 3 Feet At 5 Seconds.
Tuesday...North Winds Around 15 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: Northeast 4 Feet At 5 Seconds.
Tuesday Night...Northeast Winds 10 To 15 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. Winds And Seas Higher In And Near Thunderstorms.
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Area Forecast Discussion
National Weather Service New Orleans LA
1134pm CDT Thu Oct 30 2025

.SHORT TERM... (Tonight through Sunday Night) Issued at 1105pm CDT Thu Oct 30 2025

Calm, quiet and cool start to yet another autumn late-october day thanks to a dry continental airmass settling in the region dominated by weak surface high pressure building into the southern US. Cold Air Advection continues to back off, but is not "fully" shut down yet looking at the 00Z RAOB (Radiosonde Observation or Upper-Air Observation) and short-term HRRR (High-Resolution Rapid Refresh) proximity soundings, showing around 15-20 kt northerly flow at around 3-8kft AGL. Meanwhile at the surface winds have relaxed to nearly calm at most sites from around 0-3kts. Given ample clear skies and (mostly) calm winds, radiational cooling will keep us chilly overnight bottoming out in the 40's for most areas. Could even see a few low 40's or an isolated upper 30 in traditionally cooler locations in southern MS, the Pearl River/Pascagoula drainage basins. Warmer for the Southshore as northerly flow across warmer tidal lakes (60-70F) modifies the air, resulting in lows generally in the mid 50's come daybreak Friday morning. Otherwise, we'll warm up again today into the upper 60's to low 70's with bright blue skies and ample sunshine. Lowered dewpoints again from 17-01Z trending towards the 25th percentile to account for deep/strong PBL mixing, but overall, a beautiful day.

Same story going into Saturday, but focus begins to shift at our next system approaching the area from the northwest. As mentioned yesterday, a broad zonal trough digs south over the northern Plains/northern MS valley region being slingshot from a departing deeper shortwave trough over New England. This will send this disturbance south into the central/southern MS valley region this weekend. Also mentioned yesterday was the low confidence scenario in associated rain chances with this system, as long-range guidance diverged largely from heavy rain to not even a drop of rain across the area. Now that 24 hours have passed, diving deep into the guidance yet again reveals (slightly) increasing confidence, but still some doubts. Going over it all, trough amplification remains in question which relates to the degree of associated downstream ascent/forcing and available moisture return in the NW Gulf. Stronger/more amplified trough would uptick attendant isentropic ascent over top weak easterly surface to low- level flow in a overrunning light stratiform precipitation regime. While this appears plausible, the question comes from 1) What will be the extent of precipitation in regards to areal coverage and 2) What about the intensity. For now, what we have in the Probability of Precipitation seems plausible and any small adjustment upwards would be negligibly noticed. The 01Z keeps 20-25% Probability of Precipitation for the immediate coast and across SE LA and transitions lower to 7-14% for the I-10/12 corridor on north where forcing is limited (with drier air as well) and the trough doesn't quite amplify downstream ascent in time as it quickly passes east. Will advertise the rain to be generally light and off/on for now and not anticipating any impactful issues. We'll see how this plays out and how trends continue if any adjustments are needed.

One way or the other, once this system gets out of here, it'll be out of here in a hurry with clearing skies Sunday with a breezy north wind. KLG

Long Term
(Monday through Thursday night) Issued at 1105pm CDT Thu Oct 30 2025

Starting the new week chilly yet again, as low temps bottom out back into the 40's areawide to the low/mid 50's for the Southshore both Monday and Tuesday mornings. Didn't get too cute here but would'nt be surprised we end up a few degrees colder than what we're seeing this morning, perhaps a few more notable upper 30 degree readings depending on the extent of radiational cooling, primarily Monday morning.

Beyond that, hard to find a single drop of rain all next week but one thing is certain, we're going to warm back up mid/late week as anonymously strong, nearly 594dm ridging begins to dominate the southern US and northern Gulf. That'll support highs into the 80's for several areas Wednesday thru Friday. Not exactly the cool fall weather like we've been seeing, but still overall quiet. KLG

Marine
Issued at 1105pm CDT Thu Oct 30 2025

We'll continue to see occasionally breezy offshore winds tonight ranging 10-15kts, mainly for Gulf zones through sunrise but the general trend will be winds becoming lighter going into the day today with waves/seas diminishing thanks to high pressure building into the region. Next system approaches the area late Saturday into early Sunday bringing about a 12 hour period of off/on light rain for mainly Gulf waters. Once this system quickly departs the area early Sunday, offshore flow will set in once again and becoming breezy reaching exercise caution criteria at around 10-15kts and wind gusts 15 to reaching around 20 knots for offshore 20-60nm Gulf zones. Will see how the winds trend over the next few days to determine the need for Small Craft Advisory conditions, which appears plausible. Otherwise, turning calm/dry going into the rest of the middle to later parts of next week. KLG

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