Marine Weather and Tide Forecast for Port Isabel, TX
 | Sunrise 7:18 AM Sunset 7:27 PM Moonrise 3:32 PM Moonset 1:28 AM |
Marine Forecasts
NOTE: Zones updated 4/16/2026. Some zones changed. Use Edit if needed.
GMZ130 Laguna Madre From The Port Of Brownsville To The Arroyo Colorado- Laguna Madre From The Arroyo Colorado To 5 Nm North Of Port Mansfield Tx- Laguna Madre From 5 Nm North Of Port Mansfield To Baffin Bay Tx- 147 Pm Cdt Mon Sep 21 2026
Tonight - East winds 10 to 15 knots, becoming southeast 5 to 10 knots after midnight. Light chop on the bay.
Tuesday - East winds around 5 knots, becoming northeast in the afternoon, then becoming east 10 to 15 knots late in the afternoon. Smooth on the bay, increasing to light chop in the afternoon, then increasing to a moderate chop late in the afternoon. A slight chance of Thunderstorms.
Tuesday night - East winds 10 to 15 knots, diminishing to 5 to 10 knots after midnight. Light chop on the bay. A slight chance of showers early in the morning.
Wednesday - East winds 5 to 10 knots, increasing to 10 to 15 knots in the afternoon. A moderate chop on the bay. A slight chance of Thunderstorms. A chance of showers until late afternoon, then a slight chance of showers late in the afternoon.
Wednesday night - East winds 10 to 15 knots, diminishing to 5 to 10 knots after midnight. A moderate chop on the bay, diminishing to light chop after midnight. A slight chance of showers and Thunderstorms early in the evening. A slight chance of showers after midnight.
Thursday - East winds 5 to 10 knots, increasing to 10 to 15 knots in the afternoon. A moderate chop on the bay. A chance of showers. A slight chance of Thunderstorms in the afternoon. A chance of Thunderstorms late in the afternoon.
Thursday night - East winds 10 to 15 knots, diminishing to 5 to 10 knots after midnight. A moderate chop on the bay, diminishing to light chop after midnight. A chance of Thunderstorms with a slight chance of showers early in the evening. A slight chance of showers after midnight.
Friday - East winds 5 to 10 knots, increasing to 10 to 15 knots in the afternoon. A moderate chop on the bay. A slight chance of Thunderstorms. A chance of showers until late afternoon, then a slight chance of showers late in the afternoon.
Friday night - East winds 10 to 15 knots, diminishing to 5 to 10 knots in the late evening and overnight. A moderate chop on the bay, diminishing to light chop in the late evening and overnight. A slight chance of showers and Thunderstorms early in the evening.
Saturday - East winds 5 to 10 knots. Light chop on the bay. A slight chance of showers. A slight chance of Thunderstorms in the afternoon.
Saturday night - East winds 5 to 10 knots, becoming southeast after midnight. Light chop on the bay. A slight chance of showers and Thunderstorms early in the evening.
winds and waves higher in and near Thunderstorms.
winds and waves higher in and near Thunderstorms.
GMZ100 147 Pm Cdt Mon Sep 21 2026
Synopsis - Light to moderate winds and slight to moderate seas are forecast to continue through the week. Daily chances for showers and Thunderstorms with rain chances increasing mid to late week.
7 Day Forecast for Marine Location Near Port Isabel, TX
NEW! Add second zone forecast
| Port Isabel Click for Map Mon -- 02:27 AM CDT Moonset Mon -- 04:04 AM CDT 1.78 feet High Tide Mon -- 07:17 AM CDT Sunrise Mon -- 04:32 PM CDT Moonrise Mon -- 06:39 PM CDT 0.43 feet Low Tide Mon -- 07:26 PM CDT Sunset Tide / Current data from XTide NOT FOR NAVIGATION |
Port Isabel, Laguna Madre, Texas, Tide feet
| 12 am |
| 1.4 |
| 1 am |
| 1.6 |
| 2 am |
| 1.7 |
| 3 am |
| 1.8 |
| 4 am |
| 1.8 |
| 5 am |
| 1.8 |
| 6 am |
| 1.7 |
| 7 am |
| 1.7 |
| 8 am |
| 1.6 |
| 9 am |
| 1.6 |
| 10 am |
| 1.5 |
| 11 am |
| 1.4 |
| 12 pm |
| 1.3 |
| 1 pm |
| 1.2 |
| 2 pm |
| 1 |
| 3 pm |
| 0.9 |
| 4 pm |
| 0.7 |
| 5 pm |
| 0.5 |
| 6 pm |
| 0.4 |
| 7 pm |
| 0.4 |
| 8 pm |
| 0.5 |
| 9 pm |
| 0.6 |
| 10 pm |
| 0.8 |
| 11 pm |
| 1.1 |
| Laguna Madre Channel Click for Map Flood direction 266 true Ebb direction 86 true Mon -- 12:47 AM CDT 0.27 knots Max Flood Mon -- 01:23 AM CDT 0.27 knots Min Flood Mon -- 02:27 AM CDT Moonset Mon -- 03:29 AM CDT 0.30 knots Max Flood Mon -- 06:00 AM CDT 0.23 knots Min Flood Mon -- 07:17 AM CDT Sunrise Mon -- 07:59 AM CDT 0.26 knots Max Flood Mon -- 12:25 PM CDT -0.00 knots Slack Mon -- 04:31 PM CDT Moonrise Mon -- 04:54 PM CDT -0.52 knots Max Ebb Mon -- 07:26 PM CDT Sunset Mon -- 10:02 PM CDT 0.00 knots Slack Tide / Current data from XTide NOT FOR NAVIGATION |
Laguna Madre Channel, SW end (depth 3 ft), Texas Current, knots
| 12 am |
| 0.3 |
| 1 am |
| 0.3 |
| 2 am |
| 0.3 |
| 3 am |
| 0.3 |
| 4 am |
| 0.3 |
| 5 am |
| 0.3 |
| 6 am |
| 0.2 |
| 7 am |
| 0.2 |
| 8 am |
| 0.3 |
| 9 am |
| 0.2 |
| 10 am |
| 0.2 |
| 11 am |
| 0.2 |
| 12 pm |
| 0.1 |
| 1 pm |
| -0.1 |
| 2 pm |
| -0.3 |
| 3 pm |
| -0.4 |
| 4 pm |
| -0.5 |
| 5 pm |
| -0.5 |
| 6 pm |
| -0.5 |
| 7 pm |
| -0.4 |
| 8 pm |
| -0.3 |
| 9 pm |
| -0.1 |
| 10 pm |
| -0 |
| 11 pm |
| 0.1 |
FXUS64 KBRO 212300 AAA AFDBRO
Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 600 PM CDT Mon Sep 21 2026
New AVIATION
KEY MESSAGES
Updated at 558 PM CDT Mon Sep 21 2026
- Rain chances will increase tomorrow and Wednesday and linger through the weekend
- Temperatures remain warm but ease off a few degrees from widespread areas of low 100s along/west I-69 E to mostly upper 90s by Tuesday.
- Pockets of extreme risks of heat-related illnesses (level 4/4) are likely to continue for more populated portions of the RGV/Rio Grande Plains through this week while the rest of the region experiences moderate to major risks (level 2/4 and 3/4).
DISCUSSION
Issued at 1211 PM CDT Mon Sep 21 2026
Will continue to see a somewhat unsettled weather pattern through the forecast period. High pressure will prevail over Deep South Texas with easterly fetch bringing in excess moisture to the region, leading to low rain chances early this week, mainly along the sea breeze. As we head into mid to late week, a surface boundary will move into central Texas enhancing deep moisture across the region leading to more scattered to numerous sea breeze showers and thunderstorms. Rain chances Tuesday will be 20-40% increasing to around 30-50% Wednesday through Friday. Rain chances will taper off this weekend into next week.
Heat Risk will remain Moderate to Extreme over the next week, though increased cloud cover and/or showers and thunderstorms could bring a little relief. Temperatures will still remain above normal into mid to upper 90s to low triple digits though Wednesday through Friday could struggle to reach the triple digits with excess cloudcover and rain chances. Heat indices will peak each afternoon between 105-110 degrees.
AVIATION
(00Z TAFS)
Issued at 558 PM CDT Mon Sep 21 2026
VFR will prevail at the aerodromes through the next 24 hours, with light to moderate winds with breezy gusts and clear to partly cloudy skies. Convection is possible, but will be too isolated to warrant a mention in the current issuance of TAFs.
MARINE
Issued at 1211 PM CDT Mon Sep 21 2026
Generally favorable conditions will prevail with light to moderate easterly winds with seas around 2-3 ft and 6-7 second periods. Daily chances of showers and thunderstorms could lead to locally enhanced winds and seas.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 80 96 80 96 / 10 30 30 50 HARLINGEN 76 99 76 98 / 0 30 30 50 MCALLEN 79 101 79 99 / 0 40 30 50 RIO GRANDE CITY 77 101 77 99 / 10 40 20 50 SOUTH PADRE ISLAND 83 90 83 90 / 10 30 20 40 BAYVIEW/PORT ISABEL 79 94 79 94 / 10 30 30 50
BRO WATCHES/WARNINGS/ADVISORIES
None.
Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 600 PM CDT Mon Sep 21 2026
New AVIATION
KEY MESSAGES
Updated at 558 PM CDT Mon Sep 21 2026
- Rain chances will increase tomorrow and Wednesday and linger through the weekend
- Temperatures remain warm but ease off a few degrees from widespread areas of low 100s along/west I-69 E to mostly upper 90s by Tuesday.
- Pockets of extreme risks of heat-related illnesses (level 4/4) are likely to continue for more populated portions of the RGV/Rio Grande Plains through this week while the rest of the region experiences moderate to major risks (level 2/4 and 3/4).
DISCUSSION
Issued at 1211 PM CDT Mon Sep 21 2026
Will continue to see a somewhat unsettled weather pattern through the forecast period. High pressure will prevail over Deep South Texas with easterly fetch bringing in excess moisture to the region, leading to low rain chances early this week, mainly along the sea breeze. As we head into mid to late week, a surface boundary will move into central Texas enhancing deep moisture across the region leading to more scattered to numerous sea breeze showers and thunderstorms. Rain chances Tuesday will be 20-40% increasing to around 30-50% Wednesday through Friday. Rain chances will taper off this weekend into next week.
Heat Risk will remain Moderate to Extreme over the next week, though increased cloud cover and/or showers and thunderstorms could bring a little relief. Temperatures will still remain above normal into mid to upper 90s to low triple digits though Wednesday through Friday could struggle to reach the triple digits with excess cloudcover and rain chances. Heat indices will peak each afternoon between 105-110 degrees.
AVIATION
(00Z TAFS)
Issued at 558 PM CDT Mon Sep 21 2026
VFR will prevail at the aerodromes through the next 24 hours, with light to moderate winds with breezy gusts and clear to partly cloudy skies. Convection is possible, but will be too isolated to warrant a mention in the current issuance of TAFs.
MARINE
Issued at 1211 PM CDT Mon Sep 21 2026
Generally favorable conditions will prevail with light to moderate easterly winds with seas around 2-3 ft and 6-7 second periods. Daily chances of showers and thunderstorms could lead to locally enhanced winds and seas.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 80 96 80 96 / 10 30 30 50 HARLINGEN 76 99 76 98 / 0 30 30 50 MCALLEN 79 101 79 99 / 0 40 30 50 RIO GRANDE CITY 77 101 77 99 / 10 40 20 50 SOUTH PADRE ISLAND 83 90 83 90 / 10 30 20 40 BAYVIEW/PORT ISABEL 79 94 79 94 / 10 30 30 50
BRO WATCHES/WARNINGS/ADVISORIES
None.
Wind History for Port Isabel, TX
toggle option: (graph/table)
Link to 5 hour of 5 minute data for KSPL
Terminal Aerodrome Forecast (TAF) for KSPL
Wind History Graph: SPL
(wind in knots)
GEOS Local Image of gulf of mexico
Edit Hide
Brownsville, TX,
NOTICE: Some pages have affiliate links to Amazon. As an Amazon Associate, I earn from qualifying purchases. Please read website Cookie, Privacy, and Disclamers by clicking HERE. To contact me click HERE. For my YouTube page click HERE
X