Marine Weather and Tide Forecast for Grand Isle, LA

SHORT TERM
(Now through Monday night)
Issued at 1049 PM CDT Thu Oct 15 2026

A strong cold front will enter the area around noon today and move through the area by evening. Strong northerly winds will be produced by this front which will be responsible for bringing some very dry air and cooler temps. It will feel like the first real hint of fall. The issue will be with fire weather and marine conditions. Fire weather(Red Flag) watch/warning criteria hinge on 3 variables while a gale watch/warning and wind advisories are only 1. This means that these different headlines can be seperated in time by quite a bit like they will be in this release since it will take a bit for the proper RH values to be realized. We will be bringing the gale warning up with this package and keeping the fire watch but include the Miss coast. A wind advisory will also be released with this package as we should see frequent gusts to around 30 mph behind this front.

Currently, the high behind the front over TX is beginning to bridge it(move over it). This is causing the large area of sh/ts to dissipate rapidly this morning. All that will be left will be a few lingering showers but mainly a cloud line with the front. Fog will still be a possibility this morning but soundings show cloud develop is much more favored at 5kft rather than at the sfc. But if cloud cover can't form above the sfc, the second preference is the sfc if enough heating can be lost. This will not be an issue tonight. Winds will ease a bit over the weekend but will still be around 10 to 15 mph possibly into Monday.

LONG TERM
(Tuesday through Thursday night) Issued at 1049 PM CDT Thu Oct 15 2026

Going into the long term period, the upper level ridge will continue to build into the region from the northwestern Gulf. This will help with a warming trend early to mid week next week with daytime highs, especially across the interior are forecast to warm into the mid and upper 80s...close to 90s in the more extreme cases. At the surface, pressure gradient remains rather tight especially over the marine zones and adjacent coastal areas. This could be less than ideal from a Fire Weather perspective. Surface winds will be somewhat lighter over the interior where the lower more critical RH values will reside. So, although not impossible to need additional fire weather headlines, for now it appears the best parameters are a bit separated. (Frye)

AVIATION
(12Z TAFS)
Issued at 550 AM CDT Fri Oct 16 2026

VFR conditions are expected to remain through this taf cycle. A strong cold front will move through later today with gusty northerly winds to near 30kt. No RA or TS impacts expected.

MARINE
Issued at 1049 PM CDT Thu Oct 15 2026

A strong cold front will move through late today and tonight, bringing strong northerly gales and rapidly building seas. A gale warning has been issued beginning this evening and continuing through Saturday evening. Winds will begin slowly ease a bit over some of the protected waters Saturday which will allow gale headlines to be replaced with advisories into Sunday. Winds will gradually turn easterly Sunday and continue to slowly ease to around 20kt late Sunday. These conditions are expected to last into the start of the new work week.

LIX WATCHES/WARNINGS/ADVISORIES
LA...Wind Advisory from 4 PM this afternoon to 3 PM CDT Saturday for LAZ034>037-039-046>048-056>058-064-070-071-076>087-089>100.

Fire Weather Watch from Saturday morning through Saturday evening for LAZ034>037-039-046>048-056-057-071-076-079>086.

GM...Gale Warning from 7 PM this evening to midnight CDT Saturday night for GMZ529-531>536-541-543-551-553-554-557-570-572- 575-577.

MS...Wind Advisory from 4 PM this afternoon to 3 PM CDT Saturday for MSZ068>071-077-083>088.

Fire Weather Watch from Saturday morning through Saturday evening for MSZ068>071-077-080>082.

GM...Gale Warning from 7 PM this evening to midnight CDT Saturday night for GMZ531>536-541-543-551-553-554-557-570-572-575- 577.