Marine Weather Net

Port Fourchon Louisiana to Lower Atchafalaya River Louisiana Marine Forecast


TONIGHT

S
WINDS
10 - 15
KNOTS

WEDNESDAY

SW
WINDS
10 - 15
KNOTS

WEDNESDAY NIGHT

NE
WINDS
20 - 25
KNOTS

THURSDAY

NE
WINDS
20 - 25
KNOTS

The Marine Weather Forecast In Detail:
GMZ550 Forecast Issued: 249 PM CST Tue Feb 27 2024

SMALL CRAFT ADVISORY IN EFFECT FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING
Tonight...South Winds 10 To 15 Knots, Increasing To 15 To 20 Knots Late This Evening And Early Morning, Then Diminishing To 10 To 15 Knots Late. Seas 3 To 5 Feet, Occasionally To 6 Feet. Patchy Fog Late This Evening And Overnight.
Wednesday...Southwest Winds 10 To 15 Knots With Gusts Up To 20 Knots, Becoming West 5 To 10 Knots In The Afternoon. Seas 3 To 5 Feet, Occasionally To 6 Feet. Patchy Dense Fog.
Wednesday Night...Northeast Winds 20 To 25 Knots, Increasing To 25 To 30 Knots After Midnight. Seas 2 To 4 Feet, Occasionally To 5 Feet, Building To 4 To 6 Feet, Occasionally To 8 Feet After Midnight.
Thursday...Northeast Winds 20 To 25 Knots With Gusts Up To 30 Knots. Seas 5 To 7 Feet, Occasionally To 9 Feet.
Thursday Night...East Winds 15 To 20 Knots, Diminishing To 10 To 15 Knots After Midnight. Seas 3 To 5 Feet, Occasionally To 6 Feet. A Slight Chance Of Showers In The Evening, Then A Chance Of Showers And Thunderstorms After Midnight.
Friday...Southeast Winds 10 To 15 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. A Chance Of Thunderstorms. Showers.
Friday Night...Southeast Winds 5 To 10 Knots. Seas 2 To 3 Feet. Showers Likely With A Chance Of Thunderstorms.
Saturday...South Winds 5 To 10 Knots. Seas 2 To 3 Feet. A Chance Of Thunderstorms. Showers Likely, Mainly In The Morning.
Saturday Night...Southeast Winds 5 To 10 Knots. Seas 2 To 3 Feet. A Slight Chance Of Showers And Thunderstorms.
Sunday...East Winds 5 To 10 Knots. Seas 2 To 3 Feet. A Chance Of Showers. A Slight Chance Of Thunderstorms In The Morning, Then A Chance Of Thunderstorms In The Afternoon.
Sunday Night...Southeast Winds 10 To 15 Knots. Seas 2 To 3 Feet. A Chance Of Showers With A Slight Chance Of Thunderstorms. Winds And Seas Higher In And Near Thunderstorms.
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Area Forecast Discussion
National Weather Service New Orleans LA
527pm CST Tuesday Feb 27 2024

Long Term
(Friday through Monday night) Issued at 119pm CST Tuesday Feb 27 2024

A largely zonal flow pattern will develop over the area on Friday and remain in place through next Monday. Embedded within this zonal flow regime, a series of fast moving shortwave troughs will sweep through the area. The first of these shortwave features will be moving through the area on Friday. Ample deep layer forcing will tap into a moderately unstable and extremely moist airmass to produce widespread rain with some embedded elevated thunderstorm activity. The majority of the instability will above a fairly strong inversion extending down to the surface from around 900mb. This stable layer below 900mb will keep surface based convection at bay, but PWATs (Precipitable Waters) around 1.5 inches will support periods of locally heavy rainfall. Rainfall totals on Friday of up to 3 inches locally cannot be ruled out. By Friday night, the strongest forcing will shift to the east along with the parent shortwave trough. Weak negative vorticity advection into the region will lead to some drying aloft, and PWATs (Precipitable Waters) will fall to around an inch. The low levels will remain very moist as a onshore flow persists, and this will keep skies overcast and the threat of showers in place. Additionally, the light onshore flow and dewpoints near 60 degrees will support the development of advection fog Friday night into Saturday morning. Some of the fog could be locally dense at times.

Saturday will see a difluent flow pattern develop and remain in place through Sunday. At the same time, the nose of a 120 knot upper level jet will move into the area. The combination of difluence aloft and more favorable jet dynamics will support the formation of a broad region of higher omega values and forcing over the forecast area. Continued onshore flow will also usher in a warmer and more unstable surface based airmass, and surface based CAPE will begin to rise to between 1000 and 1500 J/KG for Saturday and Sunday afternoon. Although there is no well defined low level forcing mechanism noted, enough instability will be in place to support scattered shower and thunderstorm development each day as temperatures warm into the mid to upper 70s. During the overnight hours, the development of low clouds and some advection fog can be expected both Saturday and Sunday nights. However, winds may remain just elevated enough to keep more widespread dense fog from forming. Confidence in the fog potential will increase over the next few days.

On Monday, another shortwave trough axis will approach the region. Increasing positive vorticity advection will induce stronger deep layer forcing over the area. This increased lift will tap into the warm, moist, and moderately unstable airmass to produce scattered to numerous showers and thunderstorms. Once again, this convection will be surface based, but a lack of favorable low level shear will keep any severe potential limited. The main concern will once again be the threat of some locally heavy rainfall as PWATs (Precipitable Waters) surge back up to around 1.5 inches. The convective threat will linger into Monday night and Tuesday as the shortwave trough moves through the area. Model spread is bit higher early next week as there remain timing differences with this system, and have opted to stick with the NBM deterministic forecast for now.

Marine
Issued at 119pm CST Tuesday Feb 27 2024

Winds begin to lay down a bit leading up to frontal passage through the area on Wednesday. Post-front, due to pressure gradients, thresholds should easily be met for Small Craft Advisory which was issued with this forecast package. Hazardous marine conditions will remain through midweek as pressure gradient remains rather tight as a relatively strong high pressure moves eastward across the Ohio River Valley. Some improvement is anticipated toward the end of the week, but still moderate winds and seas will linger through the end of the forecast period.

NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...Small Craft Advisory from 6pm Wednesday to midnight CST Thursday night for LAZ068.

GM...Small Craft Advisory from 6pm Wednesday to midnight CST Thursday night for GMZ530-532-534-536-538-550-552-555-557- 570-572-575-577.

MS...None. GM...Small Craft Advisory from 6pm Wednesday to midnight CST Thursday night for GMZ532-534-536-538-550-552-555-557-570- 572-575-577.