Southwest Pass of the Mississippi River to Port Fourchon, LA 20 - 60 NM Marine Forecast
|Today...North Winds 20 To 25 Knots. Seas 3 To 6 Feet Building To 5 To 8 Feet With Occasional Seas To 10 Feet. Dominant Period 5 Seconds.|
|Tonight...North Winds 25 To 30 Knots. Seas 8 To 12 Feet With Occasional Seas To 14 Feet. Dominant Period 7 Seconds.|
|Saturday...North Winds 20 To 25 Knots. Seas 8 To 12 Feet With Occasional Seas To 13 Feet Subsiding To 4 To 7 Feet With Occasional Seas To 9 Feet. Dominant Period 5 Seconds In The Afternoon.|
|Saturday Night...Northwest Winds 10 To 15 Knots Becoming West After Midnight. Seas 3 To 6 Feet. Dominant Period 5 Seconds. Waves Or Seas Subsiding To 2 To 4 Feet. Dominant Period 5 Seconds After Midnight.|
|Sunday...West Winds 10 To 15 Knots. Seas 1 To 2 Feet. Dominant Period 4 Seconds.|
|Sunday Night...Southwest Winds 10 To 15 Knots Becoming South After Midnight. Seas 1 To 3 Feet. Dominant Period 4 Seconds.|
|Monday...Southeast Winds 15 To 20 Knots. Seas 2 To 4 Feet Building To 3 To 5 Feet With Occasional Seas To 6 Feet. Dominant Period 5 Seconds In The Afternoon. Slight Chance Of Showers In The Afternoon.|
|Monday Night...Southeast Winds 25 To 30 Knots. Seas 4 To 7 Feet With Occasional Seas To 9 Feet Building To 6 To 10 Feet With Occasional Seas To 11 Feet. Dominant Period 6 Seconds. Chance Of Showers In The Evening, Then Showers Likely And Slight Chance Of Thunderstorms After Midnight.|
|Tuesday...South Winds 20 To 25 Knots. Seas 8 To 12 Feet With Occasional Seas To 13 Feet. Dominant Period 8 Seconds. Showers Likely In The Morning. Slight Chance Of Thunderstorms Through The Day. Chance Of Showers In The Afternoon.|
|Tuesday Night...South Winds 15 To 20 Knots. Seas 5 To 8 Feet With Occasional Seas To 10 Feet. Dominant Period 8 Seconds. Chance Of Showers Through The Night.|
| Synopsis for Pascagoula to SW Pass Mississippi - GMZ501|
Synopsis for SW Pass Mississippi River to Atchafalaya River- GMZ500
332 AM CST Fri Jan 28 2022
High pressure will build in behind the overnight cold front this afternoon and remain in place through Monday. A low pressure system should pass through the waters next Tuesday.
| Area Forecast Discussion|
National Weather Service New Orleans LA
318am CST Fri Jan 28 2022
Upper troughing moving southeastward toward the area, currently extending from Missouri into New Mexico. Northwesterly winds across the area at 3am CST with pretty solid mid and high level cloud deck. These clouds are holding temperatures in the 40s for most of the area. Dew points in the mid and upper 20s northwest, in the 30s elsewhere.
.SHORT TERM (through Sunday night)... Upper trough blasts through the area this afternoon and evening, but the airmass is too dry to produce precipitation. Not anticipating any weather systems in the wake of the trough through the weekend.
Main concern will be temperatures. Mid and high cloud cover should hang around a good bit of the day, but do expect to see some sunshine late in the day. Have trended daytime highs toward the upper end of guidance today and Saturday. Overnight lows pretty much in the middle of the guidance envelope tonight and tomorrow night. Not anticipating any cold weather headlines for tonight. Northern areas are expected to remain above Hard Freeze criteria (25F), and areas around New Orleans are expected to remain just above freezing. Beyond Saturday night, a moderating trend in temperatures will commence, with highs in the mid and upper 60s, perhaps approaching 70 on Sunday in some locations.
Afternoon relative humidities could drop into the mid 20s, or potentially even lower on Saturday. 35
.LONG TERM (Monday and beyond)... A potent upper level vorticity max embedded within the southern stream will sweep through the forecast area Monday into Tuesday. Monday will see return flow increase in advance of the system, and this will allow for an increase in low level moisture and high dewpoints into the region. However, some lingering dry air in the mid and upper levels of the atmosphere will produce a strong capping inversion Monday afternoon. As a result, only some marine layer strato-cumulus development is expected beneath the inversion, and a dry forecast is in place through the afternoon hours for much of the CWA. The onshore flow regime in the low levels will allow for warmer than normal temperatures with highs expected to climb into the 60s and possibly lower 70s.
A deeper pool of Pacific based moisture will feed into the area Monday night and Tuesday and this will rapidly moisten the mid and upper levels. The cap is expected to break, and a moist adiabatic profile should take hold of the area. Despite the very strong dynamic forcing in place, a lack of instability will limit most of the precipitation to the form of showers as the system moves through on Tuesday. The only area where lapse rates appear to be favorable enough to produce some modest instability is over the open Gulf waters, and a slight chance of thunderstorms has been placed in the forecast for the waters south of Louisiana. Strong directional shear will also be in place and this will produce storm relative helicity values on the order of 200 to 400m2/s2. Thus, any thunderstorms that do form over the Gulf waters will have the potential to turn strong and even severe. Again, this system does bear watching over the weekend, as any hint of steeper lapse rates and increased instability over land could lead to a higher risk of severe storms. At this time, that is not currently called, but the probability is not zero.
In the wake of this potent system, a zonal southwesterly flow regime will remain over the Gulf South for Wednesday. This southwest flow pattern will allow for continued moisture and warm air advection into the region, and an extended period of cloud cover, marine layer showers, and likely some advection fog can be expected while this pattern remains in place. Temperatures will remain warmer than average with highs climbing into the upper 60s and lower 70s and lows only dipping into the 50s. The advection fog could potentially be dense if all of the parameters come together Wednesday night into Thursday morning.
Thursday will see another southern stream short wave trough axis move through the area. Ample positive vorticity advection, favorable jet dynamics, and a strong cold front should produce a band of showers and thunderstorms. This line of convection should sweep through during the day on Thursday, but the threat of severe convection appears to be lower due to lower shear and instability parameters. This system will also need to be monitored over the coming days as any change in the depth or tilt of the trough axis could increase shear parameters across the region. The front should push through the area by Thursday night, and a colder airmass should begin to move into the region. PG
No changes to current configuration of headlines, with Small Craft Advisory going into effect this morning, and the Gale Warning overnight. Winds will slowly relax Saturday afternoon. Moderate to strong onshore flow returns Monday night.
NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...None. GM...Small Craft Advisory from 9am this morning to 6pm CST this evening for GMZ536-538-550-552-555-557-570-572-575-577.
Gale Warning from 6pm this evening to 9am CST Saturday for GMZ536-538-550-552-555-557-570-572-575-577.
Small Craft Advisory from 9am this morning to 6am CST Saturday for GMZ530-532-534.
MS...None. GM...Small Craft Advisory from 9am this morning to 6pm CST this evening for GMZ538-550-552-555-557-570-572-575-577.
Gale Warning from 6pm this evening to 9am CST Saturday for GMZ538-550-552-555-557-570-572-575-577.
Small Craft Advisory from 9am this morning to 6am CST Saturday for GMZ532-534.