Port Fourchon Louisiana to Lower Atchafalaya River Louisiana Marine Forecast
|Today...South Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 5 Seconds. Showers Likely And Chance Of Thunderstorms In The Morning, Then Showers With Thunderstorms Likely In The Afternoon.|
|Tonight...South Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 4 Seconds. Chance Of Showers And Thunderstorms.|
|Monday...Southwest Winds 10 To 15 Knots. Seas 1 To 2 Feet. Dominant Period 4 Seconds. Showers Likely And Chance Of Thunderstorms.|
|Monday Night...Southwest Winds 5 To 10 Knots. Seas 1 To 2 Feet. Dominant Period 4 Seconds. Slight Chance Of Showers And Thunderstorms Through The Night.|
|Tuesday...West Winds 5 To 10 Knots. Seas 1 To 2 Feet. Dominant Period 4 Seconds. Chance Of Showers And Thunderstorms.|
|Tuesday Night...West Winds 5 To 10 Knots Becoming Northwest 15 To 20 Knots After Midnight. Seas 1 To 2 Feet Building To 2 To 4 Feet After Midnight. Dominant Period 4 Seconds. Slight Chance Of Showers And Thunderstorms.|
|Wednesday...North Winds 15 To 20 Knots. Seas 3 To 6 Feet. Dominant Period 4 Seconds. Slight Chance Of Showers And Thunderstorms.|
|Wednesday Night...North Winds 15 To 20 Knots. Seas 3 To 5 Feet With Occasional Seas To 6 Feet. Dominant Period 4 Seconds.|
|Thursday...Northeast Winds 15 To 20 Knots. Seas 3 To 5 Feet. Dominant Period 4 Seconds.|
|Thursday Night...Northeast Winds 15 To 20 Knots. Seas 2 To 4 Feet. Dominant Period 4 Seconds.|
| Synopsis for Pascagoula to SW Pass Mississippi - GMZ501|
Synopsis for SW Pass Mississippi River to Atchafalaya River- GMZ500
412 AM CDT Sun Sep 19 2021
A seabreeze cycle will dominate the waters through Monday. A front will approach the waters on Tuesday and pass through the waters by Wednesday afternoon. High pressure will then build in from the north by Thursday.
| Area Forecast Discussion|
National Weather Service New Orleans LA
406am CDT Sunday September 19 2021
Upper trough over Louisiana is stuck to the south of a Great Lakes ridge. Northern stream troughs are along the east and west coasts. Some convection over marine areas this morning, but not nearly the amount of coverage compared to the last week or so. Early morning temperatures and dew points remain in the lower and middle 70s.
.SHORT TERM (through Tuesday night)... Upper trough currently over Louisiana will gradually shear out over the next few days. Still have abundant deep layer moisture and forcing, so the daily diurnally induced convection will continue, generally commencing over land in the late morning along lake and sea breeze boundaries. As the afternoons progress, the convection will spread further inland, and then dissipate with the loss of heating during the evening. Moisture levels do decrease a bit for Monday and Tuesday, so the areal coverage should gradually shrink over the next couple of days. With precipitable water values remaining near 2 inches today, still a heavy rain threat, but storm motion should be enough to avoid any widespread problems. As areal coverage shrinks Monday and Tuesday, so does the heavy rain threat.
Inversions during the late night hours could aid in fog development the next few mornings, but don't expect it to be wide enough to present significant travel problems.
Regarding temperatures, don't expect much change in overnight lows the next couple of nights. High temperatures today should be fairly similar to yesterday, primarily in the mid 80s, although a few areas that don't get rained on could get a little warmer. Monday, and even moreso Tuesday, with the areal coverage of convection expected to decrease, that may allow temperatures to increase into the upper 80s to around 90. There are still a few Louisiana Parishes with significant utility issues, so there may be a need for Heat Advisories in some of those parishes tomorrow and/or Tuesday. 35
.LONG TERM (Wednesday and beyond)... Strong upper level trough extending from the upper Great Lakes region southward will amplify, bringing a cold front down into the area. This front should be moving in Tuesday night or early Wednesday, eventually pushing offshore later in the day, flushing out most of the precipitation chances and bringing cooler temperatures and lower humidity. High temperatures are looking to be in the upper 70s to lower 80s and low temps hovering in the 50s and low 60s from Wednesday afternoon onward.
Upper level ridging and surface high pressure will then begin to build in with an early taste of fall like weather will be in store through at least Saturday. Any significant increase in moisture, and associated rain chances, is unlikely to occur until onshore flow returns, which currently is not anticipated until at least next Sunday. Overall the weather pattern should pleasant and be a welcome respite for the area. -BL/35
Outside of the gusty wind and waterspout threat from developing convection, the pattern will remain fairly benign over the coastal waters through Tuesday afternoon. Gradient winds will typically range around 10 knots and seas of 1 to 3 feet are anticipated. However, a strong cold front will sweep through the waters on Wednesday. Winds will quickly shift to the northwest and strong cold air advection over the warmer waters will allow for winds of 15 to 25 knots to mix down to the surface. Seas will also increase to 4 to 7 feet in the open gulf waters and 3 to 5 feet in the sounds and lakes as these winds persist into Thursday. Small craft advisory or exercise caution headlines will likely be necessary from Wednesday through Thursday.
NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...None. GM...None. MS...None. GM...None.