Marine Weather Net

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


TODAY

NE
WINDS
15 - 20
KNOTS

TONIGHT

E
WINDS
10 - 15
KNOTS

THURSDAY

E
WINDS
10 - 15
KNOTS

THURSDAY NIGHT

SE
WINDS
15 - 20
KNOTS

The Marine Weather Forecast In Detail:
GMZ572 Forecast Issued: 357 AM CDT Wed Mar 29 2023

SMALL CRAFT ADVISORY IN EFFECT UNTIL 10 AM CDT THIS MORNING
Today...Northeast Winds 15 To 20 Knots. Gusts Up To 30 Knots. Seas 4 To 6 Feet, Occasionally To 8 Feet This Morning. A Slight Chance Of Showers Late This Morning And Afternoon.
Tonight...East Winds 10 To 15 Knots With Gusts Up To 25 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet.
Thursday...East Winds 10 To 15 Knots With Gusts Up To 25 Knots. Seas Around 3 Feet.
Thursday Night...Southeast Winds 15 To 20 Knots With Gusts Up To 25 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet.
Friday...Southeast Winds 10 To 15 Knots With Gusts Up To 20 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet.
Friday Night...South Winds 10 To 15 Knots With Gusts Up To 20 Knots. Seas Around 4 Feet, Occasionally To 5 Feet.
Saturday...Southwest Winds 5 To 10 Knots, Becoming West In The Afternoon. Seas Around 4 Feet, Occasionally To 5 Feet. A Slight Chance Of Showers And Thunderstorms In The Morning.
Saturday Night...East Winds 5 To 10 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet.
Sunday...East Winds 5 To 10 Knots. Seas Around 3 Feet. A Slight Chance Of Showers. A Slight Chance Of Thunderstorms In The Afternoon.
Sunday Night...Southeast Winds 10 To 15 Knots. Seas Around 3 Feet. A Slight Chance Of Showers And Thunderstorms. Winds And Seas Higher In And Near Thunderstorms.
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Area Forecast Discussion
National Weather Service New Orleans LA
351am CDT Wednesday Mar 29 2023

...New SHORT TERM, LONG TER
Marine
.SHORT TERM... (Today through Thursday) Issued at 345am CDT Wednesday Mar 29 2023

Last night's cold front has moved well out into the central Gulf of Mexico, ushering much cooler and drier air into the area. A shortwave moving across the northern Gulf is keeping cirrus level clouds across much of the area. This should be the case most of the day today as the cloud shield extends as far southwest as northern Mexico. I suppose it wouldn't be an absolute shock if a sprinkle or two of rain occurred out of mid level clouds near the coast, but measurable rainfall with this shortwave should be difficult to come by over land. The shortwave should exit to the east this evening, with upper ridging transiting the northern Gulf tonight and Thursday. Much less in the way of cloud cover expected on Thursday.

Early this morning, temperatures ranged from near 50 over southwest Mississippi to the mid 60s at Boothville. Much of the area was reporting dew points in the 40s, but ranged from the upper 30s over southwest Mississippi to the lower 50s at Boothville. Main temperature question today is how much the cirrus deck retards warming. Deterministic NBM numbers look pretty reasonable considering the clouds. Would note that the deterministic NBM dew points appear to be too high north of Interstate 10 today. Have used a mix of the ConsShort and NBM 10th percentile, which puts me several degrees lower than neighboring offices, but still about 5 degrees more moist than the MET/MAV values, which tend to verify better in cool, dry advection patterns.

For tonight, lowered overnight lows several degrees in the Pascagoula and Pearl River drainage basins, per the usual adjustments under good radiational cooling situations. On Thursday, NBM deterministic numbers should be reasonable.

Long Term
(Thursday night through Tuesday) Issued at 345am CDT Wednesday Mar 29 2023

Next significant system, currently impacting the Pacific Coast, will be exiting the Rockies Thursday night and Friday. Moderate onshore flow will increase moisture levels Thursday night and Friday, with dewpoints returning to at least the mid 60s by Friday afternoon. The upper trough and surface low will be well removed from the local area, centered over Nebraska at midday Friday. As the deepening system moves into the Great Lakes Friday night, it will swing a cold front toward the local area after sunset Friday. Not out of the question that we could be on the southern end of a line of storms Friday night, but better moisture and shear profiles will be well to the north of the area, to the north of Interstate 20.

Likely to take most of the day Saturday for the front to make it through the local area, if it can. The deterministic ECMWF (European Centre for Medium-Range Weather Forecasts) does move the front into the Gulf by Saturday night, while the GFS isn't quite that aggressive. That produces a 5-10 degree spread in the global deterministic max/mins for Saturday night into Monday. Currently, the NBM numbers favor the warmer GFS (Global Forecast System) based solution.

Another strong system exits the southern Rockies next Tuesday or Tuesday night with significant spread between the globals on timing and location of the surface system (ECMWF stronger and further north). Will ride the NBM for now on Probability of Precipitation and temperatures.

For Monday and Tuesday, the warmer NBM and GFS high temperatures are approaching record territory away from water sources. NBM deterministic has 90 for Baton Rouge Tuesday. A 90 degree reading in southeast Louisiana the first week of April is rather rare. Questionable how much, if any, cooling occurs at midweek next week.

Marine
Issued at 345am CDT Wednesday Mar 29 2023

Extended Small Craft Advisory to mid-morning today, as it'll take a bit for winds/waves to relax. Onshore flow returning late Thursday night into Friday will likely require Exercise Caution headlines as winds return to the 15-20 knot range through at least most of the day Friday. For right now, marine conditions look fairly favorable over the weekend, although with questions on the frontal timing and strength, confidence in details is lower than I'd like.

NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...None. GM...Small Craft Advisory until 10am CDT this morning for GMZ530-532- 534-536-538-550-552-555-557-570-572-575-577.

MS...None. GM...Small Craft Advisory until 10am CDT this morning for GMZ532-534- 536-538-550-552-555-557-570-572-575-577.