Marine Weather and Tide Forecast for Grand Isle, LA
May 17, 2024 12:01 AM CDT (05:01 UTC) Change Location
 | Sunrise 6:04 AM Sunset 7:49 PM Moonrise 2:42 PM Moonset 2:50 AM |
GMZ552 Expires:202405171715;;345006 Fzus54 Klix 170409 Cwflix
coastal waters forecast national weather service new orleans la 1109 pm cdt Thu may 16 2024
pascagoula to atchafalaya river out to 60 nm
seas are provided as a range of the average height of the highest 1/3 of the waves - .along with the occasional height of the average highest 10 percent of the waves.
gmz550-552-171715- coastal waters from port fourchon la to lower atchafalaya river la out 20 nm- coastal waters from the southwest pass of the mississippi river to port fourchon louisiana out 20 nm- 1109 pm cdt Thu may 16 2024
.tornado watch 251 in effect until 3 am cdt Friday - .
.small craft advisory in effect through late Friday night - .
Overnight - South winds 15 to 20 knots with gusts up to 30 knots. Seas 3 to 5 feet, occasionally to 6 feet. Wave detail: southeast 3 feet at 5 seconds. Showers likely with a slight chance of Thunderstorms late this evening, then a chance of showers and Thunderstorms. A slight chance of showers and Thunderstorms late.
Friday - South winds 15 to 20 knots, diminishing to 10 to 15 knots in the afternoon. Gusts up to 30 knots. Seas 3 to 5 feet, occasionally to 6 feet. Wave detail: south 4 feet at 5 seconds. A slight chance of showers and Thunderstorms in the afternoon.
Friday night - South winds 15 knots with gusts up to 20 knots. Seas 2 to 4 feet, occasionally to 5 feet. Wave detail: south 4 feet at 8 seconds. A chance of showers and Thunderstorms. Visibility 1 nm or less.
Saturday - South winds around 10 knots. Seas 2 to 4 feet, occasionally to 5 feet. Wave detail: south 4 feet at 8 seconds. Showers likely with a chance of Thunderstorms. Visibility 1 nm or less in the morning.
Saturday night - Southwest winds 5 to 10 knots. Seas 2 to 4 feet, occasionally to 5 feet. Wave detail: south 4 feet at 9 seconds. A slight chance of showers and Thunderstorms.
Sunday - Northwest winds around 5 knots. Seas 2 to 3 feet. Wave detail: south 3 feet at 8 seconds.
Sunday night - Southwest winds around 5 knots. Seas around 2 feet. Wave detail: south 2 feet at 7 seconds.
Monday - East winds around 5 knots, becoming southeast around 5 knots in the afternoon. Seas 1 to 2 feet. Wave detail: south 2 feet at 7 seconds.
Monday night - South winds 5 to 10 knots. Seas 1 to 2 feet. Wave detail: south 2 feet at 6 seconds.
Tuesday - Southeast winds 5 to 10 knots. Seas 1 to 2 feet. Wave detail: south 2 feet at 6 seconds.
Tuesday night - South winds around 10 knots. Seas around 2 feet.
winds and seas higher in and near Thunderstorms.
coastal waters forecast national weather service new orleans la 1109 pm cdt Thu may 16 2024
pascagoula to atchafalaya river out to 60 nm
seas are provided as a range of the average height of the highest 1/3 of the waves - .along with the occasional height of the average highest 10 percent of the waves.
gmz550-552-171715- coastal waters from port fourchon la to lower atchafalaya river la out 20 nm- coastal waters from the southwest pass of the mississippi river to port fourchon louisiana out 20 nm- 1109 pm cdt Thu may 16 2024
winds and seas higher in and near Thunderstorms.
GMZ500 1109 Pm Cdt Thu May 16 2024
Synopsis for pascagoula to atchafalaya river out 60 nm -
a warm front will lift northeastward across the waters through tonight. Southeasterly winds will increase to small craft advisory levels in wake of the frontal passage. Multiple rounds of Thunderstorms will bring the potential for an extended period of hazardous conditions on the waters through Saturday morning.
a warm front will lift northeastward across the waters through tonight. Southeasterly winds will increase to small craft advisory levels in wake of the frontal passage. Multiple rounds of Thunderstorms will bring the potential for an extended period of hazardous conditions on the waters through Saturday morning.
Area Discussion for - New Orleans/Baton Rouge, LA
HIDE HelpNOTE: mouseover dotted underlined text for definition
FXUS64 KLIX 162157 AFDLIX
Area Forecast Discussion National Weather Service New Orleans LA 457 PM CDT Thu May 16 2024
New SHORT TERM, LONG TERM
SHORT TERM
(This evening through Saturday)
We are heading into quite an active period of weather with multiple rounds of storms through Saturday morning. This will bring us an extended risk for flash flooding and severe weather during the short term.
A warm front was located just off the LA coast this afternoon. This boundary marks the leading edge of a very moist, unstable airmass.
While there is a temperature gradient across the boundary aloft, it not very noticeable at the surface owing to much stronger boundary- layer heating on land north of the it vs over the water.
Low-level convergence and isentropic lift along the warm front will serve as a focus for convective development through tonight. Showers and storms has so far today has been confined to coastal LA, but this activity will increase this evening as the MCS that is currently over eastern TX and northwest LA moves into the area. The environment will become increasingly supportive of heavy rainfall producers as the deeper moisture arrives behind the warm front (PWATs increase from 1.2 to 2.1 inches this evening). Although this system should be progressive as it is embedded in fast zonal flow aloft, the west-east orientation of the convection on the southern flank of the MCS will bring the potential for storms to track over the same areas. Additionally, the northward progress of the surface warm front may slow once it meets up with the cold pool on the southern periphery of the complex. This will provide a favorable setup for flash flooding across a narrow west-east corridor of the area. The latest CAMs continue to highlight areas along and north of the I-10/I-12 corridor to be under the axis of heaviest rainfall tonight. The latest guidance continues to suggest a quick 2-3" with isolated amounts of 4-5" with the storms. The Flood Watch was expanded southward earlier in the day to include both the Northshore and Southshore of LA and MS Coast. There is also a severe thunderstorm threat this evening into the early overnight hours but it is highly conditional on convection being able to become rooted in the boundary layer. The opportunity for surface-based convection is narrow and dependent on storms on the southern flank of the MCS being able to develop south of the warm front.
A "relative" lull in showers and storms is still expected behind the departing MCS during the day Friday from about mid morning through early afternoon as warm front lifts just north of our area. Expect additional storms to develop during the mid to late afternoon as the boundary layer quickly destabilizes during peak heating. Plenty of disagreement among the CAMs regarding how widespread the convection will become later Friday afternoon and evening.
However, a highly unstable airmass fueled by a moist boundary layer and steep mid- level lapse rates will support a risk of damaging wind gusts and large hail with this second round.
But wait...there's more. A third round is expected Friday night (especially overnight) into Saturday morning. Convection will be aided by favorable synoptic dynamics ahead of a sharpening shortwave trough and upper jet streak. Accordingly, convection should grow upscale, resulting in another round of heavy rainfall and flash flooding.
LONG TERM
(Saturday through Wednesday night)
Issued at 320 PM CDT Thu May 16 2024
The upper-level trough will be departing our area on Sunday and northwest flow kicks in on the backside. Due to the upstream ridging across the southern Plains, surface high pressure will filter in across the area starting on Sunday. This will keep the area dry and warm on Sunday.
The aforementioned ridging will slide east over our area by Monday.
This will cause temps to increase further throughout the week. The suppression from the ridge will also keep us mostly dry, although the onshore winds will pump moisture into the area.
AVIATION
(18Z TAFS)
Issued at 103 PM CDT Thu May 16 2024
VFR this afternoon with mid level clouds from upstream convection overspread the area. CU field eventually building from SW to NE across the area later this afternoon and early evening as a warm front progress northward. A complex of showers and storms currently over C and NE TX will move in from the west this evening as it interacts with a northward moving warm front.
Attempted to narrow the timing window of storms based on the current observations and latest model guidance, but there is still some uncertainty with the onset timing. There is some indication that storms could arrive a couple of hours earlier than what's advertised in the 18Z TAFs (as early as 01Z for BTR/MCB, 03Z for MSY/HDC/NEW/ASD and 04Z for GPT/HUM). The latest TAFs also show CIGs and VSBYs lowering to MVFR shortly after the onset.
Also added a 2-3 hour TEMPO IFR group late this evening and overnight for all TAFs except HUM as confidence of storms making it this far is lower. In reality, conditions will deteriorate to IFR at the onset with brief/local restrictions near LIFR in heavy downpours.
Some of the model guidance in indicating the potential for a wake low to develop late in the day. Easterly winds would strengthen overnight for at least 2-3 hours as a result. Forecast wind speeds may be underdone.
A relative lull in the showers and storms are expected Friday morning and afternoon in wake of the overnight MCS. However, it may not be entirely convection free with a few showers and storms lingering near MCB and GPT during the morning. Additional storms are expected to develop during peak heating hours, especially during the latter half of the afternoon as it will likely take some time to recover from the earlier activity.
MARINE
Issued at 103 PM CDT Thu May 16 2024
A warm front was located over the coastal waters of LA. A slight wind shift from easterly to southeasterly is occurring with the frontal passage. Wind speeds will also increase from around 10 kt to 15 kt with occasional gusts to 20 kt. This boundary will continue to lift northeastward through the rest of the waters through the evening.
Storms have already developed just behind the surface boundary across our far southwestern zones early this afternoon. Locally strong wind gusts of 30-40 kt is possible with the strongest convection.
Additional showers and storms are expected to move in this evening and continue overnight. The highest coverage will be over the lakes and MS Sound as convection becomes focused along the warm front. Have ise SCA for tonight owing to the presence of a wake low behind the storms. There is a potential for a brief 1-3 hour period of gales depending on where the wake low tracks and how strong it is as it approaches our area.
PRELIMINARY POINT TEMPS/POPS
MCB 65 83 67 84 / 90 70 70 50 BTR 71 89 70 89 / 80 70 60 50 ASD 71 89 70 87 / 70 60 60 70 MSY 75 89 73 87 / 60 50 70 60 GPT 71 85 70 85 / 70 50 70 70 PQL 70 87 70 85 / 70 50 60 80
LIX WATCHES/WARNINGS/ADVISORIES
LA...Small Craft Advisory until 6 AM CDT Saturday for LAZ068.
Flood Watch from 7 PM CDT this evening through Saturday morning for LAZ034>037-039-046>048-057-058-060-064-071-076>087-089.
GM...Small Craft Advisory until 6 AM CDT Saturday for GMZ530-534-550- 552-570-572.
Small Craft Advisory from 7 PM this evening to 6 AM CDT Saturday for GMZ532-536-538-555-557-575-577.
MS...Flood Watch from 7 PM CDT this evening through Saturday morning for MSZ068>071-077-083>088.
GM...Small Craft Advisory until 6 AM CDT Saturday for GMZ534-550-552- 570-572.
Small Craft Advisory from 7 PM this evening to 6 AM CDT Saturday for GMZ536-538-555-557-575-577.
Area Forecast Discussion National Weather Service New Orleans LA 457 PM CDT Thu May 16 2024
New SHORT TERM, LONG TERM
SHORT TERM
(This evening through Saturday)
We are heading into quite an active period of weather with multiple rounds of storms through Saturday morning. This will bring us an extended risk for flash flooding and severe weather during the short term.
A warm front was located just off the LA coast this afternoon. This boundary marks the leading edge of a very moist, unstable airmass.
While there is a temperature gradient across the boundary aloft, it not very noticeable at the surface owing to much stronger boundary- layer heating on land north of the it vs over the water.
Low-level convergence and isentropic lift along the warm front will serve as a focus for convective development through tonight. Showers and storms has so far today has been confined to coastal LA, but this activity will increase this evening as the MCS that is currently over eastern TX and northwest LA moves into the area. The environment will become increasingly supportive of heavy rainfall producers as the deeper moisture arrives behind the warm front (PWATs increase from 1.2 to 2.1 inches this evening). Although this system should be progressive as it is embedded in fast zonal flow aloft, the west-east orientation of the convection on the southern flank of the MCS will bring the potential for storms to track over the same areas. Additionally, the northward progress of the surface warm front may slow once it meets up with the cold pool on the southern periphery of the complex. This will provide a favorable setup for flash flooding across a narrow west-east corridor of the area. The latest CAMs continue to highlight areas along and north of the I-10/I-12 corridor to be under the axis of heaviest rainfall tonight. The latest guidance continues to suggest a quick 2-3" with isolated amounts of 4-5" with the storms. The Flood Watch was expanded southward earlier in the day to include both the Northshore and Southshore of LA and MS Coast. There is also a severe thunderstorm threat this evening into the early overnight hours but it is highly conditional on convection being able to become rooted in the boundary layer. The opportunity for surface-based convection is narrow and dependent on storms on the southern flank of the MCS being able to develop south of the warm front.
A "relative" lull in showers and storms is still expected behind the departing MCS during the day Friday from about mid morning through early afternoon as warm front lifts just north of our area. Expect additional storms to develop during the mid to late afternoon as the boundary layer quickly destabilizes during peak heating. Plenty of disagreement among the CAMs regarding how widespread the convection will become later Friday afternoon and evening.
However, a highly unstable airmass fueled by a moist boundary layer and steep mid- level lapse rates will support a risk of damaging wind gusts and large hail with this second round.
But wait...there's more. A third round is expected Friday night (especially overnight) into Saturday morning. Convection will be aided by favorable synoptic dynamics ahead of a sharpening shortwave trough and upper jet streak. Accordingly, convection should grow upscale, resulting in another round of heavy rainfall and flash flooding.
LONG TERM
(Saturday through Wednesday night)
Issued at 320 PM CDT Thu May 16 2024
The upper-level trough will be departing our area on Sunday and northwest flow kicks in on the backside. Due to the upstream ridging across the southern Plains, surface high pressure will filter in across the area starting on Sunday. This will keep the area dry and warm on Sunday.
The aforementioned ridging will slide east over our area by Monday.
This will cause temps to increase further throughout the week. The suppression from the ridge will also keep us mostly dry, although the onshore winds will pump moisture into the area.
AVIATION
(18Z TAFS)
Issued at 103 PM CDT Thu May 16 2024
VFR this afternoon with mid level clouds from upstream convection overspread the area. CU field eventually building from SW to NE across the area later this afternoon and early evening as a warm front progress northward. A complex of showers and storms currently over C and NE TX will move in from the west this evening as it interacts with a northward moving warm front.
Attempted to narrow the timing window of storms based on the current observations and latest model guidance, but there is still some uncertainty with the onset timing. There is some indication that storms could arrive a couple of hours earlier than what's advertised in the 18Z TAFs (as early as 01Z for BTR/MCB, 03Z for MSY/HDC/NEW/ASD and 04Z for GPT/HUM). The latest TAFs also show CIGs and VSBYs lowering to MVFR shortly after the onset.
Also added a 2-3 hour TEMPO IFR group late this evening and overnight for all TAFs except HUM as confidence of storms making it this far is lower. In reality, conditions will deteriorate to IFR at the onset with brief/local restrictions near LIFR in heavy downpours.
Some of the model guidance in indicating the potential for a wake low to develop late in the day. Easterly winds would strengthen overnight for at least 2-3 hours as a result. Forecast wind speeds may be underdone.
A relative lull in the showers and storms are expected Friday morning and afternoon in wake of the overnight MCS. However, it may not be entirely convection free with a few showers and storms lingering near MCB and GPT during the morning. Additional storms are expected to develop during peak heating hours, especially during the latter half of the afternoon as it will likely take some time to recover from the earlier activity.
MARINE
Issued at 103 PM CDT Thu May 16 2024
A warm front was located over the coastal waters of LA. A slight wind shift from easterly to southeasterly is occurring with the frontal passage. Wind speeds will also increase from around 10 kt to 15 kt with occasional gusts to 20 kt. This boundary will continue to lift northeastward through the rest of the waters through the evening.
Storms have already developed just behind the surface boundary across our far southwestern zones early this afternoon. Locally strong wind gusts of 30-40 kt is possible with the strongest convection.
Additional showers and storms are expected to move in this evening and continue overnight. The highest coverage will be over the lakes and MS Sound as convection becomes focused along the warm front. Have ise SCA for tonight owing to the presence of a wake low behind the storms. There is a potential for a brief 1-3 hour period of gales depending on where the wake low tracks and how strong it is as it approaches our area.
PRELIMINARY POINT TEMPS/POPS
MCB 65 83 67 84 / 90 70 70 50 BTR 71 89 70 89 / 80 70 60 50 ASD 71 89 70 87 / 70 60 60 70 MSY 75 89 73 87 / 60 50 70 60 GPT 71 85 70 85 / 70 50 70 70 PQL 70 87 70 85 / 70 50 60 80
LIX WATCHES/WARNINGS/ADVISORIES
LA...Small Craft Advisory until 6 AM CDT Saturday for LAZ068.
Flood Watch from 7 PM CDT this evening through Saturday morning for LAZ034>037-039-046>048-057-058-060-064-071-076>087-089.
GM...Small Craft Advisory until 6 AM CDT Saturday for GMZ530-534-550- 552-570-572.
Small Craft Advisory from 7 PM this evening to 6 AM CDT Saturday for GMZ532-536-538-555-557-575-577.
MS...Flood Watch from 7 PM CDT this evening through Saturday morning for MSZ068>071-077-083>088.
GM...Small Craft Advisory until 6 AM CDT Saturday for GMZ534-550-552- 570-572.
Small Craft Advisory from 7 PM this evening to 6 AM CDT Saturday for GMZ536-538-555-557-575-577.
| Stations | Dist | Age | Wind | Air Temp | Water Temp | Waves | inHg | DewPt |
| GISL1 - 8761724 - Grand Isle, LA | 0 mi | 43 min | SE 9.9G | 79°F | 80°F | 29.74 | ||
| 42084 | 25 mi | 61 min | 79°F | 79°F | 3 ft | |||
| LOPL1 - Louisiana Offshore Oil Port, LA | 27 mi | 55 min | SSW 25G | 79°F | 4 ft | 29.74 | 77°F | |
| BURL1 - Southwest Pass, LA | 37 mi | 61 min | 19G | |||||
| PILL1 | 37 mi | 43 min | S 8G | 78°F | 73°F | 29.77 | ||
| PSTL1 - 8760922 - Pilot's East, SW Pass, LA | 37 mi | 43 min | SE 9.9G | 77°F | 73°F | 29.76 | ||
| BYGL1 - 8762482 - Bayou Gauche, LA | 44 mi | 43 min | 68°F | 82°F | 29.83 | |||
| SHBL1 - 8761305 - Shell Beach, LA | 44 mi | 43 min | ESE 20G | 78°F | 74°F | 29.73 | ||
| CARL1 | 47 mi | 43 min | 75°F |
toggle option: (graph/table)
| Airport | Dist | Age | Wind kt | Vis | Sky | Weather | Temp | DewPt | RH | inHg |
| KGAO SOUTH LAFOURCHE LEONARD MILLER JR,LA | 20 sm | 26 min | S 08 | 10 sm | Overcast | Thunderstorm in Vicinity | 81°F | 75°F | 84% | 29.77 |
Tide / Current for Barataria Pass, Mississippi River Delta, Louisiana
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Barataria Pass
Click for Map
Thu -- 02:22 AM CDT Moonset
Thu -- 02:56 AM CDT 0.17 feet Low Tide
Thu -- 06:06 AM CDT Sunrise
Thu -- 01:49 PM CDT Moonrise
Thu -- 05:02 PM CDT 0.85 feet High Tide
Thu -- 07:45 PM CDT Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Click for Map
Thu -- 02:22 AM CDT Moonset
Thu -- 02:56 AM CDT 0.17 feet Low Tide
Thu -- 06:06 AM CDT Sunrise
Thu -- 01:49 PM CDT Moonrise
Thu -- 05:02 PM CDT 0.85 feet High Tide
Thu -- 07:45 PM CDT Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Barataria Pass, Mississippi River Delta, Louisiana, Tide feet
| 12 am |
| 0.3 |
| 1 am |
| 0.2 |
| 2 am |
| 0.2 |
| 3 am |
| 0.2 |
| 4 am |
| 0.2 |
| 5 am |
| 0.2 |
| 6 am |
| 0.3 |
| 7 am |
| 0.3 |
| 8 am |
| 0.4 |
| 9 am |
| 0.5 |
| 10 am |
| 0.5 |
| 11 am |
| 0.6 |
| 12 pm |
| 0.7 |
| 1 pm |
| 0.7 |
| 2 pm |
| 0.8 |
| 3 pm |
| 0.8 |
| 4 pm |
| 0.8 |
| 5 pm |
| 0.9 |
| 6 pm |
| 0.8 |
| 7 pm |
| 0.8 |
| 8 pm |
| 0.8 |
| 9 pm |
| 0.7 |
| 10 pm |
| 0.6 |
| 11 pm |
| 0.5 |
Quatre Bayous Pass
Click for Map
Thu -- 02:22 AM CDT Moonset
Thu -- 03:23 AM CDT 0.18 feet Low Tide
Thu -- 06:06 AM CDT Sunrise
Thu -- 01:48 PM CDT Moonrise
Thu -- 06:20 PM CDT 0.93 feet High Tide
Thu -- 07:45 PM CDT Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Click for Map
Thu -- 02:22 AM CDT Moonset
Thu -- 03:23 AM CDT 0.18 feet Low Tide
Thu -- 06:06 AM CDT Sunrise
Thu -- 01:48 PM CDT Moonrise
Thu -- 06:20 PM CDT 0.93 feet High Tide
Thu -- 07:45 PM CDT Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Quatre Bayous Pass, Mississippi River Delta, Louisiana, Tide feet
| 12 am |
| 0.4 |
| 1 am |
| 0.3 |
| 2 am |
| 0.2 |
| 3 am |
| 0.2 |
| 4 am |
| 0.2 |
| 5 am |
| 0.2 |
| 6 am |
| 0.3 |
| 7 am |
| 0.3 |
| 8 am |
| 0.4 |
| 9 am |
| 0.5 |
| 10 am |
| 0.5 |
| 11 am |
| 0.6 |
| 12 pm |
| 0.7 |
| 1 pm |
| 0.7 |
| 2 pm |
| 0.8 |
| 3 pm |
| 0.8 |
| 4 pm |
| 0.9 |
| 5 pm |
| 0.9 |
| 6 pm |
| 0.9 |
| 7 pm |
| 0.9 |
| 8 pm |
| 0.9 |
| 9 pm |
| 0.8 |
| 10 pm |
| 0.7 |
| 11 pm |
| 0.6 |
New Orleans/Baton Rouge, LA,
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