Marine Weather Net

High Island to Freeport, TX 20 - 60 NM Marine Forecast




15 - 20


10 - 15


10 - 15

The Marine Weather Forecast In Detail:
GMZ375 Forecast Issued: 1006 AM CST Mon Jan 18 2021

Today...Southeast Winds 15 Knots. Seas 2 To 4 Feet.
Tonight...Southeast Winds 15 To 20 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 7 Feet.
Tuesday...Southeast Winds 10 To 15 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 7 Feet.
Tuesday Night...Southeast Winds 10 To 15 Knots Becoming East 5 To 10 Knots After Midnight. Seas 3 To 5 Feet. A Slight Chance Of Showers In The Late Evening And Overnight.
Wednesday...East Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Slight Chance Of Showers.
Wednesday Night...Southeast Winds 10 To 15 Knots Becoming South After Midnight. Seas 3 To 4 Feet. A Slight Chance Of Showers.
Thursday...South Winds 10 To 15 Knots. Seas 4 Feet. A Slight Chance Of Showers In The Morning.
Thursday Night...South Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Slight Chance Of Showers In The Evening.
Friday...South Winds 10 To 15 Knots. Seas 3 To 4 Feet.
Friday Night...South Winds Around 10 Knots Becoming Southeast After Midnight. Seas 3 To 4 Feet.
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Synopsis for High Island to the Matagorda Ship Channel out 60 nautical miles including Galveston and Matagorda Bays - GMZ300
1006 AM CST Mon Jan 18 2021

Onshore flow will strengthen today and Tuesday as high pressure moves off to the east. Seas will be gradually increasing with this strengthening flow. Sea fog could develop as early as Tuesday night though more likely during Wednesday afternoon and may linger off and on for the remainder of the week and into the weekend.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
433am CST Monday Jan 18 2021

.SHORT TERM [Today through Tuesday Night]... As the surface high pressure leaves our region, southeast winds will return, bringing in some warm air advection and higher PWATs (Precipitable Waters) over SE Texas. That being said, daytime highs will reach 70 for most of our CWA and upper 60s everywhere else today and then reach the low-to-mid 70s on Tuesday. Say goodbye to freezing temps as overnight lows tonight will reach the upper 50s. Increased low-to-mid level moisture and an approaching cold front will also bring in gradual cloud coverage today.

On Tuesday, a positively tilted trough will be located over SW CONUS and nearly zonal flow will be on top of our CWA. A surface cold front is expected to push through SE Texas and stall across our northwestern counties bringing the highest rain chances over those areas. Despite daytime heating, warm theta-e advection, higher PWATs, and surface convergence along the front, heavy rain is not expected on Tuesday. This is due to residual dry air in the lower and mid-levels along with a surface inversion due left over by the previous high pressure system. However, the previous aforementioned low-level forcing/moistening mechanisms will slowly

Long Term - Wednesday Through Monday
Wednesday, rain chances continue to increase with the higher chances west of I-45. The weak cold front, now quasi-stationary in the northwestern/western region of the CWA. Higher rain chances will still stay northward, mainly north of I-10 over Wednesday night. While onshore flow continually brings gulf moisture into the area, lack of instability will keep thunderstorm development minimal at best. Thursday the system will start to drag across the CWA, mostly parallel to the coastline, which may decrease rain chances across the forecast area as lift weakens.

Friday the lift along the boundary will continue to move out the area with some chances of rain still lingering in the northeastern counties, but almost diminishes by Friday night. Friday night, winds will begin shifting northeasterly as the front pushes to the coastal waters into Saturday morning. Saturday will continue the decrease in rain trend as onshore flow returns in the evening. Sunday, onshore flow continues and rain chances return to SETX in the wake of a warm front. Monday, a cold front approaches and is expected to enter the northwestern counties in the morning and pass through the southeastern counties Monday evening. 35

Light winds this morning will become southeasterly and southerly and begin strengthening as pressures lower of W TX this afternoon. Southerly flow of 10 to 15 knots occasionally 15 to 20 knots will persist through Tuesday (the stronger winds should be out beyond 20nm). Wednesday the flow backs to the east and southeast and this should in turn increase the chances for sea fog over the colder shelf waters. Thursday the low levels slowly moisten further as winds come back to the south and the intermittent sea fog threat will likely persist into the weekend. Some differences in the extended guidance stand out going into Saturday afternoon/night with either full southeasterly flow or the frontal boundary stalling near the coast then very slowly lifting north. Confidence in timing beyond Friday diminishes quickly but overall expect a warming trend with increasing southerly flow Sunday possibly approaching SCA.


NOAA Houston/Galveston TX Office: Watches - Warnings - Advisories
TX...None. GM...None.