Marine Weather Net

Freeport to Matagorda Ship Channel, TX 20 - 60 NM Marine Forecast


TODAY

SE
WINDS
10
KNOTS

TONIGHT

SE
WINDS
10 - 15
KNOTS

FRIDAY

SE
WINDS
10 - 15
KNOTS

FRIDAY NIGHT

S
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
GMZ370 Forecast Issued: 405 AM CDT Thu Aug 22 2019

Today...Southeast Winds Around 10 Knots. Seas 2 To 3 Feet. A Chance Of Showers And Thunderstorms Until Late Afternoon, Then A Slight Chance Of Showers And Thunderstorms Late.
Tonight...Southeast Winds 10 To 15 Knots Becoming South After Midnight. Seas 3 To 4 Feet. A Slight Chance Of Showers And Thunderstorms In The Evening, Then A Chance Of Showers And Thunderstorms After Midnight.
Friday...Southeast Winds 10 To 15 Knots. Seas 3 To 4 Feet. Showers In The Morning. A Chance Of Thunderstorms. A Chance Of Showers In The Afternoon.
Friday Night...South Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Chance Of Showers In The Evening, Then Showers Likely And A Slight Chance Of Thunderstorms After Midnight.
Saturday...South Winds Around 10 Knots. Seas 3 To 4 Feet. Showers Likely In The Morning. A Slight Chance Of Thunderstorms. A Chance Of Showers In The Afternoon.
Saturday Night...South Winds Around 10 Knots. Seas 3 Feet. A Chance Of Showers And Thunderstorms.
Sunday...South Winds 5 To 10 Knots. Seas 2 To 3 Feet. A Chance Of Showers And A Slight Chance Of Thunderstorms.
Sunday Night...South Winds 10 To 15 Knots. Seas 2 To 3 Feet. A Chance Of Showers And Thunderstorms.
Monday...South Winds 10 To 15 Knots. Seas 2 To 3 Feet. A Slight Chance Of Thunderstorms In The Morning. A Chance Of Showers.
Monday Night...South Winds 10 To 15 Knots. Seas 2 To 3 Feet. A Slight Chance Of Showers In The Evening, Then A Chance Of Showers After Midnight.
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Synopsis for High Island to the Matagorda Ship Channel out 60 nautical miles including Galveston and Matagorda Bays - GMZ300
405 AM CDT Thu Aug 22 2019

Light to moderate onshore flow will continue over the next few days, with slightly higher wind speeds during the overnight hours. Scattered showers and thunderstorms will be possible through the weekend with the best coverage on Friday and Saturday. Winds and seas should slightly increase Friday as a surge of tropical moisture enters the northwestern Gulf. No tropical development is expected at this time. Onshore flow continues for the start of next week as an upper level ridge remains over Texas.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
420am CDT Thu August 22 2019

Short Term - Today through Friday Morning
GOES nighttime microphysics RGB imagery not showing much low clouds this morning or any cloud cover for that matter. Surface analysis shows a weak pressure gradient with lower pressures over the Plains contributing to some moderate onshore flow. 500mb analysis at 00Z shows some slightly lower heigheights around 592dm over the area. GOES derived precipitable water imagery does show 2" PWAT (Precipitable Water) just beyond the 60nm waters in the Gulf which should move into SE Texas later today but will be slow to do so. Water vapor imagery shows a weak TUTT low in the western Gulf with a broad area of weak convection to the east of this trough. This is basically the tropical wave that is expected to push towards the area on Friday into the weekend with an increase in shower and thunderstorm activity.

For today however, convection will take it's time to initiate as higher moisture advects into the region. Daytime heating and convergence along the sea breeze will still be needed for storms to form. Recent CAMS seem all on track with storms forming in the 15- 17Z time frame along the coast and then pushing inland. Storms may not get past a Columbus to Conroe line before dissipating in the afternoon. Convection again should be ending in the 22Z to 00Z time frame with little to no activity overnight. Like yesterday, since shower and thunderstorm activity will be more isolated to widely scattered, high temperatures will be in the mid/upper 90s with low 90s along the coast. There is a chance there could be more scattered activity along the coast that hold high temps down a little more but rather error on the high side at this point. With breaks in the clouds, it does not take much to heat the atmosphere given the ridging aloft.

.LONG TERM [Friday Morning Through Wednesday]... The extended portion of the forecast remains on track, with better coverage of showers and thunderstorms possible Friday through Saturday, before the area of disturbed weather shifts east of SE TX. This upper level trough axis is still expected to bring a surge of higher precipitable water values (PWs) between 2.1 to 2.5 inches across the Gulf waters and attempt to advect inland over the coastal counties. North of I-10, PWs drop off significantly, with the College Station forecast soundings showing PWs on Friday and Saturday closer to 1.8 to 1.9 inches. Forecast soundings also remain uncapped along the coast, with an inverted V profile indicative of potentially gusty winds beneath any stronger storms that develop. Little has changed in terms of rainfall accumulations, with 1 to 2 inches total possible from Columbus to Conroe and southward through the Thursday to early Sunday time frame. Rainfall totals closer to 2 inches will be possible along the coast.

Global guidance has flip flopped compared to last night's solutions, with GFS moving the better moisture east of SE TX faster than the NAM12. The GFS builds the upper level ridge back in over the region, edging in from the west Sunday morning, while the ECMWF and NAM12 lag behind in strength and timing by about 12 hours. Forecast soundings also show a cap of drier air in the 900-850mb layer on Sunday which should help to suppress overall coverage. Therefore Sunday into the first half of the week looks to be more of a typical summertime like pattern with PWs less than 2.0 inches and development more likely to occur along the sea/bay breezes. Otherwise, high temperatures should remain in the 90s with low temperatures in the mid 70s to low 80s over the next week.

Marine Discussion
Moderate onshore flow will continue for the end of the week. We are tracking a tropical wave now over the western Gulf that is expected to move towards the Upper TX Coast tomorrow into Saturday. This may cause a brief increase in winds and seas that could at most reach SCEC criteria before decreasing into Sunday. Again latest model guidance shows no tropical development from this system.

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