Marine Weather Net

Matagorda Bay Marine Forecast


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The Marine Weather Forecast In Detail:
GMZ330 Forecast Issued: 1013 AM CST Sat Jan 23 2021

Today...Northeast Winds 5 To 10 Knots Becoming East 10 To 15 Knots In The Afternoon. Bay Waters Smooth Becoming Slightly Choppy In The Afternoon. Areas Of Fog. Patchy Fog In The Late Morning And Afternoon. A Chance Of Showers.
Tonight...East Winds 10 To 15 Knots Becoming Southeast 5 To 10 Knots After Midnight. Bay Waters Slightly Choppy Becoming Smooth After Midnight. Areas Of Dense Fog. A Chance Of Showers.
Sunday...Southeast Winds 10 To 15 Knots. Bay Waters Slightly Choppy. Areas Of Fog. A Slight Chance Of Showers.
Sunday Night...South Winds 15 To 20 Knots. Bay Waters Choppy. Patchy Fog. A Chance Of Showers And A Slight Chance Of Thunderstorms.
Monday...West Winds 10 To 15 Knots Becoming Northwest 5 To 10 Knots In The Afternoon. Bay Waters Slightly Choppy Becoming Smooth In The Afternoon. Patchy Fog Early In The Morning. A Slight Chance Of Showers And Isolated Thunderstorms.
Monday Night...Northeast Winds 5 To 10 Knots. Bay Waters Smooth.
Tuesday...East Winds 5 To 10 Knots. Bay Waters Smooth.
Tuesday Night...East Winds Around 10 Knots Becoming Northeast After Midnight. Bay Waters Smooth To Slightly Choppy Becoming Smooth After Midnight.
Wednesday...North Winds 10 To 15 Knots. Bay Waters Slightly Choppy.
Wednesday Night...North Winds 10 To 15 Knots. Bay Waters Slightly Choppy.
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Synopsis for High Island to the Matagorda Ship Channel out 60 nautical miles including Galveston and Matagorda Bays - GMZ300
1013 AM CST Sat Jan 23 2021

The potential for dense fog will remain a concern across the bays and coastal waters through the remainder of the weekend, with the Dense Fog advisory now extended into Sunday. Some brief improvement is anticipated this afternoon, but a return to low visibilities will occur as a surface warm front approaches the coast later this afternoon. The threat of dense fog could potentially continue into Monday. Caution flags may be necessary over the Gulf waters tomorrow as moderate onshore flow develops ahead of the next disturbance. The cold front associated with this system will move through the coastal waters late Monday afternoon finally bringing an end to the sea fog threat.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1153am CST Sat Jan 23 2021

SHORT TERM [Through Sunday Night]... If there is one word that would describe the short term period, it would be: dreary. Patchy dense fog and low stratus has spread across the area this morning and these conditions will persist through the majority of the weekend. The fog will be the densest near the coast as sea fog gets blown on shore, and in low lying spots across the area. There may be a break in the overcast skies and foggy conditions in the late morning into the early afternoon, but don't expect these better conditions to last. The cold front that pushed off the coast yesterday will make a return later this evening as a warm front that slides inland. The warm, moist air behind the front will not only help sustain the patchy fog and low stratus, but also bring isolated to scattered showers across the area. The warm front will continue to move northward through the night and eventually north of the area by Sunday afternoon. This will bring the highest chance of precipitation north of the area with it, although cannot out rule an isolated shower or thunderstorm as PWATs (Precipitable Waters) will be near 1.5 inches Sunday afternoon. Breaks in the fog or overcast skies does not look likely on Sunday due to this increased moisture. Southerly flow increases Sunday night ahead of an approaching disturbance from the west (more on this in the long term below).

Temperatures this afternoon will be slightly cooler than yesterday with afternoon highs in the mid to upper 60s. With the warm front pushing inland later this evening, overnight lows will be on the warmer side with temperatures bottoming out in the low 60s for most of the area. The one exception will be for the far northern counties that most likely won't get into the warm air advection until during the day on Sunday, so overnight lows Saturday night will be in the mid to upper 50s. High temperatures on Sunday will be a few degrees warmer than today with highs in the mid 70s. With the warm front fully through the area, temperatures Sunday night will likely not dip below the mid 60s across the area.

Long Term - Monday Through Sunday
A short wave over the southern plains will get sheared out as it moves to the northeast on Monday. Low pressure over OK will head E- NE toward the Ohio River Valley and this will allow a cold front to move across the state. Still some minor timing differences but the cold front should move through the NW zones around 15z, the Houston area around 17z and the coast around 19z. PW values (Precipitable Water values) peak around 1.40 inches around 15z and drop sharply in the afternoon. Capping in the 850-700 mb layer should limit precipitation coverage especially over the southern half of the region. Over the north, there is less capping and a bit more instability so coverage north of Hwy 105 will be higher and added isolated thunder.

Skies are expected to clear Monday night in the wake of the front and dry air at the surface coupled with clear skies should lead to a night with strong radiational cooling with MinT values dropping into the low/mid 40's. Tuesday will start out sunny but some mid level moisture should give the area some afternoon clouds. 850 mb temps remain warm (around 14 C) and this would suggest MaxT values would warm up into the mid 70's. The variable will be how quick clouds return in the afternoon. Hedged my bets a bit and went with MaxT values in the lower 70's. Another short wave will move into the central plains Tues night into Wednesday. This will induce weak surface low pressure to develop over OK. The low will move quickly to the east Wednesday morning and allow a cold front to move through the area. A strong surge of high pressure will filter into the southern plains bringing cooler temperatures back to SE TX. PW values ahead of the front will remain below an inch and no rainfall is expected.

The end of the week looks cool and tranquil as high pressure remains the dominant weather feature. 850 mb temps cools significantly, down to around 8 C which would support MaxT values in the low/mid 60's. Dry air at the surface and light winds would allow nighttime temps to cool as well so leaned toward the cooler side of guidance for both MaxT and MinT values.

Some differences in the long range guidance regarding the next short wave forecast to get here on Saturday. The deterministic ECMWF (European Centre for Medium-Range Weather Forecasts) is faster than other guidance but ensemble guidance seems to support a slower solution. Out of respect for the ECMWF, have added some low PoPs for next weekend, but confidence is low at this time. 43

Marine Discussion
Sea fog will continue to be a threat through Monday morning. There may be a break, albeit brief, in the foggy conditions in the Ship Channel and upper parts of the Bays in the late morning/early afternoon hours today. A warm front moving onshore in the late afternoon/early evening will bring an end to that reprieve as warm, moist southeasterly flow begins again. Scattered showers will also accompany this warm front. Once the fog sets in after this frontal passage, it likely will continue until a cold front moves through the area Monday afternoon. Winds and wave heigheights will climb to near Caution Flag criteria late Sunday into Monday as the onshore flow increases. Conditions will be drier in the wake of Monday's cold front ending the sea fog threat for at least a few days.

NOAA Houston/Galveston TX Office: Watches - Warnings - Advisories
TX...NONE. GM...Dense Fog Advisory until noon CST Sunday for the following zones: Coastal waters from Freeport to Matagorda Ship Channel TX out 20 NM...Coastal waters from High Island to Freeport TX out 20 NM...Galveston Bay...Matagorda Bay.