Southwest Pass of the Mississippi River to Port Fourchon Louisiana Marine Forecast
|Rest Of Today...Southeast Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 3 To 5 Feet, Occasionally To 6 Feet. A Chance Of Showers And Thunderstorms.|
|Tonight...Southeast Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 3 To 5 Feet, Occasionally To 6 Feet. A Chance Of Showers And Thunderstorms.|
|Sunday...Southeast Winds 15 To 20 Knots With Gusts Up To 25 Knots. Seas 3 To 5 Feet, Occasionally To 6 Feet. Showers, Thunderstorms.|
|Sunday Night...Southeast Winds 10 To 15 Knots With Gusts Up To 20 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. Showers Likely. Thunderstorms Likely, Mainly In The Evening.|
|Monday...Southeast Winds 10 To 15 Knots With Gusts Up To 20 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. A Chance Of Thunderstorms. Showers Likely, Mainly In The Morning.|
|Monday Night...Southeast Winds 15 To 20 Knots With Gusts Up To 25 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. A Slight Chance Of Showers And Thunderstorms In The Evening.|
|Tuesday...Southeast Winds 15 To 20 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. A Slight Chance Of Showers And Thunderstorms In The Afternoon.|
|Tuesday Night...Southeast Winds 15 To 20 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. A Slight Chance Of Showers And Thunderstorms.|
|Wednesday...South Winds 15 To 20 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. A Slight Chance Of Showers And Thunderstorms In The Morning, Then A Chance Of Showers And Thunderstorms In The Afternoon.|
|Wednesday Night...South Winds 15 To 20 Knots. Seas 2 To 4 Feet, Occasionally To 5 Feet. A Chance Of Showers. A Slight Chance Of Thunderstorms In The Evening, Then A Chance Of Thunderstorms After Midnight. Winds And Seas Higher In And Near Thunderstorms.|
| Area Forecast Discussion|
National Weather Service New Orleans LA
100pm CDT Sat May 21 2022
/issued 333am CDT Sat May 21 2022/
Short Term - Today Through Monday
We will quickly transition today into a deeper tropical atmospheric profile. A weak upper low will develop later today over the central gulf while this deep moisture subducts the low. This should help explode areas of rainfall today to the east. Our deep moisture area(PW numbers around 1.7") will race NW and can be seen this morning in satellite imagery with the leading edge of this developing sh/ts in the vicinity of lat27.2N lon87.5W. This area of sh/ts will race to the northwest which is how one will be able to tell when and where the high PW boundary will be. It will move inland by late morning to around noon spreading finally into Baton Rouge by 3pm. By that time, this deep moisture should be moving over areas that have enough heating to cause another convective pulse over those areas in and around Baton Rouge. PW values (Precipitable Water values) that will be moving in will match the max moving average for 5/21. This move of deeper moisture will displace somewhat drier air to its northwest. It is the entrainment of this air that could give some high wind potential, but this is not the big game in town. The rainfall rates will be the main message. Even though there will be some heavy rainfall with some of these storms today, we can definitely use the rain initially but this may also cause the area to become primed with wet soils. The main player will be a frontal boundary that will move near the area and stall as it parallels the upper SWerly jet. It is this deep moisture interacting with this front and small disturbances in the upper flow that will give rise to a more substantial rainfall rate. Some of these may move or train over the same areas Sunday. This could start as early as Sunday morning but the main stage should be set during the late afternoon well into the evening hours Sunday. In between the convective bursts, we wil get several hours reprieve before the next. By Monday, the front may begin to dissipate while the disturbances moving through the upper jet will begin to move east and NE bringing most of the heavy rain in those directions. But that is just a break between the next feature that starts to move through afterwards. And since the deep tropical moisture connection continues well after Monday, any disturbance or focus that comes along will do the same thing. Tide levels look to behave so far but will be higher than normal. 90th percentile numbers are coming in right at and maybe a tenth higher than a few coastal flood levels at high tide times, but as we move from the spring tide cycle into a neap tide, these values should lower a bit by Monday.
LONG TERM (Monday night and beyond)... On Monday evening, upper ridging will continue to be centered off the Florida east coast, with the axis northward into the eastern Great Lakes. Upper troughing will be along the lee side of the Rockies with another ridge off the Pacific coast. The pattern progresses only slowly eastward, with the trough moving into the Mississippi River Valley by Thursday morning, and into the Great Lakes Saturday morning. Timing differences between the ECMWF (European Centre for Medium-Range Weather Forecasts) and GFS operational models have diminished to some extent, but the ECMWF remains the quicker of the two models.
Not likely to see anything resembling a surface frontal passage until perhaps Thursday or Friday. It's also going to take that long for deeper moisture to diminish, with precipitable water values remaining near or above 1.75 inches until the front passes, then falling below 1 inch at some point on Friday.
Bottom line is that there will be periods of showers and thunderstorms with each passing shortwave through at least Thursday, with the daytime hours preferred due to daytime heating differences. Don't see any reason to back away from the NBM PoPs. Will hold onto the 20-30 Probability of Precipitation for Friday for now, but later forecasts may dry out entirely. Most or all of the Memorial Day weekend now appears to be dry across the area.
Clouds and precipitation likely to hold high temperatures in the 80s during the workweek next week. The drier air will eventually see high temperatures return to the lower 90s next weekend, although if rain totals are heavy during the first half of the week, that may end up being a "target of opportunity" at some point to lower highs a bit. 35
AVIATION... SCT to BKN030 will be common and lower cigs with heavy rain can be expected at several terminals later today. MVFR (Marginal Visual Flight Rules) or lower cigs and some vis restrictions can be expected again tonight especially for those locations that get rainfall today.
Winds will be SE through the day but will rise for a short time with a surge of moisture and sh/ts moving through later this morning. SE winds may stay up for a bit behind this surge as well and so will continue the caution statements through today again. Otherwise winds will remain SE but will ease back to around 10kt for Sunday. There could be somewhat variable winds in the nearshore waters Sunday into Monday but by Tuesday these winds rise back to near or just over advisory conditions of 20-25kt through the remainder of the week while become more SWerly by the end of the week. Any thunderstorm activity will be capable of producing strong winds and higher seas abrupartly thorughout the week.
NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...None. GM...None. MS...None. GM...None.