Marine Weather and Tide Forecast for Bayou L'Ourse, LA

SHORT TERM
(Now through Thursday)
Issued at 1203 AM CDT Mon Apr 20 2026

Upper trough from New England to Florida tonight with ridging over the Rockies. A southern stream shortwave was over west Texas and northern Mexico. At the surface, high pressure was centered over Mississippi. Locally, just high clouds moving across the area. A large spread in temperatures at midnight, ranging from 45 at Pascagoula to the mid 60s in New Orleans, where northeast winds off of much warmer Lake Pontchartrain (water temp 70F) are holding temperatures up. There are showers and a few thunderstorms over central and southern Texas and the western Gulf this evening.

While the Texas shortwave will move across the area in the next 36 hours, low level easterly winds will keep feeding dry air into the area. Precipitable water values were around 0.25 inch in our most recent upper air launch, which is pretty much the bottom of the chart. We'll likely have plenty of high clouds today and Tuesday, but there's very little moisture below 600 mb. Precipitable water values don't get much above the daily mean (1.05 inches) until perhaps Wednesday afternoon, so any significant precipitation is going to have a difficult time making it east of the Atchafalaya River prior to that time. And by that point, we'll probably have lost any large scale forcing. So, while we may see some isolated to scattered convection Wednesday and/or Thursday, there's no real indications of organized precipitation through Thursday.

We'll be off to a chilly start at sunrise today across the north half of the area, where it'll be in the 40s, but the very dry air will allow temperatures to recover quickly into the mid and upper 70s, which isn't far off late April normals. Another chilly morning Tuesday morning, upper 40s and lower 50s across the north half, but beyond that point, it's back to above normal temperatures.

We'll be monitoring fire weather conditions today, as afternoon humidities will fall to around 25 percent over portions of south Mississippi and adjacent southeast Louisiana parishes, but forecast wind speeds fall a bit short of needing Red Flag Warnings.

LONG TERM
(Thursday night through Sunday)
Issued at 1203 AM CDT Mon Apr 20 2026

Medium range guidance continues to advertise a pattern shift heading into the end of the work week and weekend but there is still rather significant difference in the details from the ensembles and operational runs. There is a definite wetter vs drier scenario with the ECM and ECS on the wetter side and the GFES and GFS on the drier side with the GFS by far the driest Friday and into through the weekend. The NBM is right in the middle and is a good compromise. One thing to mention is that we are in a drought and the old saying "when in drought, leave it out" has some truth to it and over the last few months when the models were suggesting more rain in the medium range they backed off quite considerably by the time we got within a day, so leaning towards a drier scenario may be the right choice in the next few days.

Like we mentioned the ridge over the southeastern CONUS heading into the end of the work week will begin to get suppressed and nudged to the east as we begin to see the impacts of the subtropical jet. Even though the ridge does get suppressed somewhat from an amplifications standpoint the heights don't appear to fall much if any through Saturday. The flow does increase some and remains generally zonal through Saturday as well. At the sfc a sfc low is expected to slide across the southern/central Plains Friday and across the Ms Valley Friday night and into Saturday but it is filling. The trailing cold front will move into the Lower MS Valley Friday night but as the low gets farther to the northeast and the mid lvl flow begins to parallel the trailing end of the front it will struggle to move much more south. Depending on how fast it moves into the Lower MS Valley and when it eventually stalls will have significant impacts on the rain potential this weekend. Latest forecast is holding onto the 40 to possibly even 60% Friday and Saturday afternoons, mainly across the northern half of the CWA PWs are forecast to range from just below 1.2" to just abv 1.4" Friday through Sunday with the greatest concentration of deeper moisture just ahead of the slowing/stalling boundary. Given that the PoPs across the north Friday(NW) and Saturday(NE) are not unreasonable however given the quickly weakening front and it become more and more stretched out from WSW to ENE across the southern Plains and into the Lower MS Valley I could see these being a little high for Friday with the better chances likely being Saturday. The other forecast problem is highs going into the weekend. Obviously the afternoon highs will be highly dependent on rain/no rain. The wetter models are slightly cooler with LL temps suggesting highs in the lower to maybe a few mid 80s while the drier solutions have LL temps that would suggest a few upper 80s are possible. However, the morning extended MOS values have lower to mid 80s on Friday and mostly mid 80s across the board Saturday and Sunday. /CAB/

AVIATION
(06Z TAFS)
Issued at 1203 AM CDT Mon Apr 20 2026

Generally VFR conditions through the forecast period. Can't entirely rule out very patchy ground fog in a few places where winds go calm for the next 6 hours, but threat isn't high enough to mention in most areas. At forecast issuance, the only terminal it was mentioned was at KHDC. Otherwise, just cirrus moving across the area, and a general wind forecast.

MARINE
Issued at 1203 AM CDT Mon Apr 20 2026

Northeast to east winds will remain around 20 knots across most of the waters today. Small Craft Advisories remain in effect for these hazardous conditions into at least tonight, with some potential for advisories to be extended into Tuesday. Wednesday, winds will shift to a more SE direction and ease a bit to around 10-15 knots, possibly remaining that way for the remainder of the week and into the next weekend.

LIX WATCHES/WARNINGS/ADVISORIES
LA...None.
GM...Small Craft Advisory until noon CDT today for GMZ529-531>536-557.

Small Craft Advisory until 7 PM CDT this evening for GMZ541-543- 551-553-554-577.

Small Craft Advisory until 1 AM CDT Tuesday for GMZ570-572-575.

MS...None.
GM...Small Craft Advisory until noon CDT today for GMZ531>536-557.

Small Craft Advisory until 7 PM CDT this evening for GMZ543-551- 553-554-577.

Small Craft Advisory until 1 AM CDT Tuesday for GMZ572-575.