Marine Weather Net

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


TONIGHT

SE
WINDS
15
KNOTS

FRIDAY

SE
WINDS
10 - 15
KNOTS

FRIDAY NIGHT

E
WINDS
10 - 15
KNOTS

SATURDAY

E
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
GMZ370 Forecast Issued: 344 PM CDT Thu Apr 02 2020

Tonight...Southeast Winds Around 15 Knots And Gusty Decreasing To 10 To 15 Knots After Midnight. Seas 3 To 5 Feet.
Friday...Southeast Winds 10 To 15 Knots. Seas 3 To 4 Feet.
Friday Night...East Winds 10 To 15 Knots. Seas 3 Feet. A Chance Of Showers. Isolated Thunderstorms In The Late Evening And Overnight.
Saturday...East Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Slight Chance Of Thunderstorms In The Morning. Showers. A Chance Of Thunderstorms In The Afternoon.
Saturday Night...Northeast Winds 15 To 20 Knots Becoming East 10 To 15 Knots After Midnight. Seas 4 Feet. A Chance Of Showers And A Slight Chance Of Thunderstorms.
Sunday...East Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Chance Of Showers In The Morning, Then A Slight Chance Of Showers In The Afternoon.
Sunday Night...Southeast Winds 10 To 15 Knots. Seas 3 To 4 Feet.
Monday...Southeast Winds 10 To 15 Knots. Seas 3 Feet.
Monday Night...Southeast Winds 10 To 15 Knots. Seas 3 To 4 Feet.
Tuesday...South Winds 10 To 15 Knots Decreasing To 5 To 10 Knots In The Afternoon. Seas 3 Feet.
Tuesday Night...South Winds Around 10 Knots. Seas 3 Feet.
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Synopsis for High Island to the Matagorda Ship Channel out 60 nautical miles including Galveston and Matagorda Bays - GMZ300
344 PM CDT Thu Apr 2 2020

Light to moderate onshore flow through Friday. Winds may strengthen slightly this evening as an upper level disturbance moves through Texas. The chance of showers and thunderstorms increases Friday night into Saturday as a cold front moves off the coast Saturday morning with northeasterly flow. The warm front moves back into the area Sunday night with southeasterly flow returning.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
650pm CDT Thu April 2 2020

The primary forecast problem remains a focus on the arrival and slow passage of a weak cold front through the area. This front will provide a focus for showers and thunderstorms, and potentially even some flooding concerns and a few severe thunderstorms. Beyond that, however, this may kick off an unsettled period, with multiple rounds of showers and thunderstorms extending into next week. Of note:

- Longer term drought conditions will give us some cushion, and as long as rain rates are not excessive, will help us handle several inches of rain. Worries about flash flooding would increase if rain rates are higher. - With the heavier rainfall in the area and upstream, flooding is likely to be exacerbated on the Trinity River, and may emerge on other area river basins this weekend. - The focus for severe storms will likely be to our west Friday night, but development of an organized line of storms could carry some threat into our area from the west/northwest. Severe threat will diminish for Saturday as the front moves through our area.

Short Term - Friday Through Saturday Night
Active weather this go around as first shortwave is moving through the region now and overnight bringing a decent chance of showers and even a few thunderstorms. More favorable areas for thunderstorms should be north of a line form Livingston to Houston to Palacios. Greater instability above the cap to work with should be closer to the College Station region. A strong thunderstorm with gusty winds and even pea hail shouldn't be ruled out up there. After this s/w departs expect rain chances to taper down across the area before increasing as a series of s/w in the flow aloft ripples through the area painting a wet picture for the area Friday afternoon/Friday night. Profiles are very moist for this time of year but lacking somewhat in the CAPE department. More of the efficient rain maker profile for showers and thunderstorms. Still good signals in the models for isolated spots of heavy rainfall though confidence isn't high enough yet for any sort of flash flood watch. WPC has placed a good chunk of the western portions of the area in a marginal risk for heavy rainfall. Timing is still in question as well as location which is the hallmark of this type of system becoming more mesoscale driven in the Friday night/Saturday time period. Needless to say with all this moisture around don't expect much sunshine and temperatures will remain on the warm side until the cold front slides through much of the region Friday night/Saturday early morning.

.LONG TERM [Saturday Through Thursday]... Saturday morning looks to open up with the cold front more or less lined up along the border of our area of responsibility and the Fort Worth office's (the northern border of Caldwell County northeast to Houston County). That said, the precise location may be less relevant, as the surface pattern will likely be a mess over much of Southeast Texas thanks to mesoscale convective influences. The mesoscale influence continues to make the Saturday forecast extremely troublesome.

CAM guidance generally looks to shift convective focus back to the front Saturday morning, in spite of strong convection the night before pushing into our area. The one exception is the WRF-ARW, which appears to generate a strong MCV Friday night, and actually clears things out pretty well as it draws the cold front well into our area, and has only light showers on it Saturday morning. While plausible, I'm unsure if we'll have a sufficient balance of instability and shear to pull something quite that organized off. So while I can't dismiss it out of hand, I'm going with the weight of guidance in keeping solid rains across Southeast Texas today as the front drags across. I expect that while we should still manage some isolated cells with lightning, especially near the front, a lack of instability should generally keep conditions showery on Saturday.

Thus, while Friday night may carry a severe threat, the focus on Saturday will likely turn to where training rain or intense cells may emerge, posing a heavy rain/flash flooding threat. Thanks to some long term drought in place, particularly over our west and southwest, we'll have a cushion for rainfall totals, as long as the rates are not too intense. Again, a relative lack of instability may help us here, as it should tamp down the potential for any individual element to grow intense enough to cause troublesome rain rates. Still, a quick succession of strong cells could achieve more than what any individual cell could manage, plus we will have less cushion from any rain on Friday night.

Much of this far focuses on flash flooding potential. Eventually, some of the water will manage to run off to local river and stream basins, with additional contributions from upstream (this is also a concern as they have received significant rainfall of late, and have much less cushion provided than our area). For more on the riverine situation, peep the hydrology section below.

Next week seems to be gaining consensus for continued unsettled weather deep into next week. the Euro has backed off on the intense strengthening of the Gulf ridge aloft, giving us more potential for multiple quick-hitting vort maxes streaming through west/southwest flow overhead. It's still not quite as sold on the idea as the GFS, but there is a bit more consensus on the idea than the day before. While not particularly powerful, NAEFS indicates that 95+ percentile precipitable water values will not be leaving us, so even these quick hits of showers and storms may pack a bit of a punch, as shown in the GFS. Don't want to speculate on it too much though, given the subtle forcing mechanisms involved and difficulty in predicting them more than 4 days out. Let's get through this weekend first. We have time to turn our attention to next week, yet.

Hydrology
Most streamflows across southeast Texas are near normal, with the exception of much below normal conditions on the Lavaca/Navidad river basin and much above normal conditions on the Trinity River where minor/moderate river flooding is occurring.

Current forecasts/hydrographs only take into consideration 24 hours of forecast rainfall; however, the rainfall over the next 48 hours will cause widespread rises on area rivers. Most basins will see rises to action stage; however, minor and isolated moderate river flooding is possible. The heaviest rainfall is expected to occur over the Brazos River Valley, including the Navasota River, which makes this area our primary concern for new river impacts. With that said, additional rainfall over the Trinity River basin will only exacerbate ongoing flooding conditions, making this our primary concern for continued river impacts. Elsewhere, rainfall is needed to help the current drought conditions. Soils can handle the rainfall totals; however, it is where the intense rainfall rates set up that we will have flooding concerns.

This weekend's rainfall is fairly manageable; however, with a wet pattern setting up for next week, additional rainfall will likely fall on top of routed water from upstream rainfall. We will need to keep an eye on developing conditions.

Tropical
Just a quick pre-season arrival to note the presentation of Colorado State's early hurricane season forecast. Their forecasts are always interesting, usually generate conversation, and are a good way to remind ourselves that tropical season is on the way!

What these forecasts don't include, is whether or not Southeast Texas can be impacted. Regardless of how busy the season as a whole is, it only takes a single storm to ruin our summer. So, while we definitely welcome today's forecast, we also want to emphasize that we all need to be prepared for hurricane season no matter what that forecast says. It may be extra important this year to get an early start, as it may take extra planning and patience to ensure our hurricane kits are completely ready to go by June 1!

And with that, hopefully this portion of the AFD lies dormant until June 1...or even later, that would be fine, too.

NOAA Houston/Galveston TX Office: Watches - Warnings - Advisories
TX...High Rip Current Risk through Friday morning for the following zones: Brazoria Islands...Galveston Island and Bolivar Peninsula...Matagorda Islands.

GM...None.