Marine Weather Net

Southwest Pass of the Mississippi River to Port Fourchon Louisiana Marine Forecast


TONIGHT

SW
WINDS
10 - 15
KNOTS

SUNDAY

N
WINDS
10 - 15
KNOTS

SUNDAY NIGHT

E
WINDS
10 - 15
KNOTS

MONDAY

E
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
GMZ552 Forecast Issued: 342 PM CDT Sat Apr 10 2021

Tonight...Southwest Winds 10 To 15 Knots Becoming Northwest After Midnight. Seas 3 To 5 Feet With Occasional Seas To 6 Feet. Dominant Period 7 Seconds. Slight Chance Of Showers And Thunderstorms After Midnight.
Sunday...North Winds 10 To 15 Knots Becoming East Near 5 Knots Late In The Afternoon. Seas 3 To 5 Feet. Dominant Period 6 Seconds.
Sunday Night...East Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 6 Seconds.
Monday...East Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 6 Seconds. Slight Chance Of Showers And Thunderstorms In The Afternoon.
Monday Night...Southeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 5 Seconds. Slight Chance Of Showers And Thunderstorms In The Evening.
Tuesday...East Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 5 Seconds. Chance Of Showers And Thunderstorms.
Tuesday Night...Southeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 5 Seconds. Chance Of Showers And Slight Chance Of Thunderstorms Through The Night.
Wednesday...Northeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 5 Seconds. Chance Of Showers And Thunderstorms.
Wednesday Night...Northeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 5 Seconds. Slight Chance Of Showers And Thunderstorms Through The Night.
Thursday...Northeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Chance Of Showers And Thunderstorms.
Thursday Night...East Winds 10 To 15 Knots. Seas 1 To 2 Feet.
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Synopsis for Pascagoula to SW Pass Mississippi - GMZ501
Synopsis for SW Pass Mississippi River to Atchafalaya River- GMZ500
342 PM CDT Sat Apr 10 2021

A weak front will stall over or near the northern Gulf of Mexico this weekend. Weak surface lows may develop along this boundary by the early or middle part of the week.
Area Forecast Discussion
National Weather Service New Orleans LA
328pm CDT Sat April 10 2021

Synopsis
The MCS from this morning has moved well out into the Gulf of Mexico. A trailing shortwave moving across the northern Gulf, and the cold front pushing southward has produced isolated convection to the south of Lake Pontchartrain this afternoon, which is rapidly moving eastward offshore as well. Looks like the effective boundary, based on wind fields and dew points, is somewhere around Interstate 12 at 2pm CDT. Where we've lost cloud cover sufficiently, temperatures have or will rebound to near 80 degrees, with dew points in the lower and middle 60s, compared to the lower 70s that were widespread ahead of the front.

.SHORT TERM (through Monday night)... Based on mid-level westerly flow, actual cold front may not make much more southward progress. Latest HRRR (High-Resolution Rapid Refresh) solution does indicate some threat of isolated showers overnight, so there will be a mention in a few zones. The 00z upper air soundings will be instructive as to whether an evening forecast update will be needed.

Beyond tonight, high pressure will shift eastward over the next couple of days. Low level flow will eventually turn onshore late Monday or Monday night. Moisture increase will eventually be sufficient for at least isolated to scattered convection by late Monday night or Tuesday morning.

Temperature guidance is pretty well clustered through Monday, and don't see much of a reason to mess with it. 35

.LONG TERM (Tuesday and beyond)... Main upper air pattern gets pretty blocky north of 35N at mid- week, with a surface boundary getting hung up somewhere close to the Gulf Coast. Weak shortwaves moving through the zonal flow to the south of the block across our area will present the threat of a few rounds of convection during the midweek period. The ECMWF solution is a little more vigorous with one on Tuesday, the GFS with one on Wednesday. At this point, severe weather doesn't appear to be as much of a concern as the potential for at least some heavy rain at midweek. Considering that we've had a couple of batches of heavy rain in the last few days, we'll need to monitor for any focus of heavy rain. We'll keep to the blended Probability of Precipitation and temperatures for now. 35

Marine
Wind and pressure fields (especially direction) have been rather chaotic today due to the morning convection. Winds have dropped below Small Craft Advisory criteria, and with the pressure field weakening somewhat, will cancel the Small Craft Advisory, which was due to expire shortly, anyway. Outside of thunderstorms toward midweek, don't see any major marine issues for the majority of this forecast package. 35

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