Marine Weather Net

Baffin Bay to Port Mansfield, TX 20 - 60 NM Marine Forecast


REST OF TODAY

SE
WINDS
5 - 10
KNOTS

TONIGHT

SE
WINDS
5 - 10
KNOTS

WEDNESDAY

SE
WINDS
10 - 15
KNOTS

WEDNESDAY NIGHT

SE
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
GMZ175 Forecast Issued: 917 AM CDT Tue Jun 22 2021

Rest Of Today...Southeast Winds 5 To 10 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 7 Feet. Chance Of Showers And Thunderstorms.
Tonight...Southeast Winds 5 To 10 Knots Increasing To 10 To 15 Knots After Midnight. Seas 3 To 5 Feet. Chance Of Showers And Thunderstorms.
Wednesday...Southeast Winds 10 To 15 Knots. Seas 3 To 5 Feet. Slight Chance Of Showers And Thunderstorms.
Wednesday Night...Southeast Winds 10 To 15 Knots. Seas 3 To 5 Feet.
Thursday...Southeast Winds 10 To 15 Knots. Seas 3 To 5 Feet.
Thursday Night...Southeast Winds 15 To 20 Knots. Seas 3 To 5 Feet.
Friday...Southeast Winds 10 To 15 Knots. Seas 3 To 5 Feet.
Friday Night...Southeast Winds 15 To 20 Knots. Seas 3 To 5 Feet.
Saturday...Southeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Slight Chance Of Showers And Thunderstorms.
Saturday Night...Southeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Slight Chance Of Showers And Thunderstorms.
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Synopsis for Baffin Bay to Rio Grande out 60 nm: GMZ100
917 AM CDT Tue Jun 22 2021

A weak area of low pressure in the Bay of Campeche and a weak stationary front across central Texas will help maintain a weak pressure gradient along the lower Texas coast through Wednesday. Light east to southeast winds with moderate seas will prevail as a result. High pressure becomes re- established over the Gulf the latter half of the week with an increase in winds and bump in seas. Showers and thunderstorms increase in coverage through the day today and tonight.
Area Forecast Discussion
...UPDATED National Weather Service Brownsville TX
1241pm CDT Tuesday Jun 22 2021

AVIATION...Patches of MVFR (Marginal Visual Flight Rules) cigs early this morning should become primarily VFR broken-overcast mid-late morning and afternoon outside of expected convection. Showers and thunderstorms to develop through the day with isolated stronger convection possible. Lower visibility and ceilings likely in and near convection. VFR conditions are expected this evening and overnight. Light southeast to east winds today and tonight.

Short Term - Today Through Wednesday
vorticity maximum along the base of an NE-SW elongated mid-level trough rotates around the eastern periphery of the 500mb ridge centered over the Desert SW. Models project this disturbance to move along the Texas coast and over Deep South Texas today. Advertised sufficient atmospheric moisture, daytime heating and outflow boundaries from ongoing and southward moving convection, across Southcentral Texas, should allow for development of convection clusters mid-late morning and into the afternoon hours. Latest derived GOES-16 Total precipitable water values range from 1.8 to 2.1 inches with models projecting a respectable 1.9-2.25 inches for the afternoon hours. Quantitative Precipitation Forecast values from WPC and 12Z model output are lower this morning in the 0.25-0.50 inch range, however, a band of convection northwest of San Antonio has been producing 0.5-1+ inch values with some locally higher amounts. Confidence is above average that some locations will see better than an inch of rain today. Although, not mentioned in the grids/forecast, can not rule out a few strong thunderstorms with potential for small hail and gusty winds with a high cape low shear environment in place. Temperatures for the day will likely reach the low/mid 90s before the rain sets in and cool off back into the 80s or possible the upper 70s when a good storm passes overhead.

Tonight and Wednesday...some convection lingers across portions of the Rio Grande Valley this evening before waning before midnight as the elongated trough and disturbance drifts south of the border. 500mb ridge re- establishes back over Texas Wednesday but residual moisture across the eastern portions of the CWA, daytime heating and the seabreeze should be enough to spark at least a slight chance of showers/tstms mainly along and east of the I 69C. Temperatures are forecast to remain at or slightly above normal tonight and right at normal for Wednesday highs. With humidity levels expected to be rather high, heat indices rebound well above the century mark but below heat advisory levels.

Long Term - Wednesday Night through Monday
A mid level ridge will build over Texas through much of the workweek, helping to cut off any mentionable rain chances through the rest of the week and into the start of the weekend. Then the combination of a mid level trough that will dive into the Plains this weekend and an inverted trough setting up over the northern Gulf of Mexico will weaken the ridge over Deep South Texas and bring back a chance of showers and thunderstorms to the area Sunday through Monday. With persistent southeasterly winds advecting Gulf moisture across the CWA and a lack of strong upper level forcing, any shower or thunderstorm activity will likely be diurnally or seabreeze driven with the best chances near the coast and offshore.

Temperatures will remain near normal through the workweek with a slight decrease on Sunday and Monday due to the increased cloud cover and PoPs. Heat indices continue to look manageable through the long term...but it will still feel hot with heat indices above 100 degrees across most of the CWA each day through Saturday.

MARINE: Today through Wednesday...Pressure gradient continues to relax as a cold front pulls up stationary along the Gulf South and northwest of the Texas coast. A light onshore flow today and Wednesday will allow for a moderate residual swell to subside through tomorrow. Showers and thunderstorms to increase later today with some lingering offshore tonight and Wednesday. Some of the storms will produce gusty winds, heavy rainfall, lightning and locally higher seas. Not expecting any small craft advisories or exercise caution wording today or Wednesday.

Wednesday Night through Monday...Moderate seas and light to moderate southeast winds can be expected through the rest of the workweek and into the weekend. There may be some brief periods of winds cranking up to 15 to 20 knots on Thursday night and Friday, but other than that, hazardous marine conditions are not expected. With a mid level trough of low pressure setting up over the Gulf of Mexico this weekend, isolated to scattered showers and thunderstorms will be possible across the lower Texas waters Saturday through early next week.


NOAA Brownsville TX Office: Watches - Warnings - Advisories
TX...None. GM...None.