Baffin Bay to Port Mansfield, TX Marine Forecast
|Rest Of Today...East Winds 5 To 10 Knots. Seas 3 To 5 Feet. Slight Chance Of Showers Through The Day. Slight Chance Of Thunderstorms In The Afternoon.|
|Tonight...East Winds 10 To 15 Knots Diminishing To 5 To 10 Knots After Midnight. Seas 3 To 5 Feet. Slight Chance Of Showers After Midnight.|
|Thursday...East Winds 5 To 10 Knots. Seas 3 To 5 Feet. Slight Chance Of Showers And Thunderstorms Through The Day.|
|Thursday Night...Southeast Winds 5 To 10 Knots. Seas 2 To 4 Feet.|
|Friday...Southeast Winds Around 5 Knots Becoming Northeast In The Afternoon. Seas 2 To 4 Feet.|
|Friday Night...East Winds 5 To 10 Knots. Seas 2 To 4 Feet.|
|Saturday...Northeast Winds 5 To 10 Knots. Seas 2 To 3 Feet.|
|Saturday Night...East Winds 5 To 10 Knots Shifting Southeast After Midnight. Seas 2 To 3 Feet.|
|Sunday...South Winds 5 To 10 Knots Becoming Southeast 10 To 15 Knots In The Afternoon. Seas 2 To 3 Feet.|
|Sunday Night...Southeast Winds 10 To 15 Knots. Seas 2 To 4 Feet.|
| Synopsis for Baffin Bay to Rio Grande out 60 nm: GMZ100|
937 AM CDT Wed Oct 21 2020
High pressure over the northern Gulf of Mexico will result in a long fetch of easterly flow across the the lower Texas coastal waters. This will lead to higher, long-period swell activity across the coastal waters the next couple of days. Seas may reach Small Craft Advisory levels for the offshore waters late tonight and into early Thursday morning. Light to moderate onshore flow is then expected through the remainder of the week along with lower sea heights.
| Area Forecast Discussion|
...UPDATED National Weather Service Brownsville TX
626am CDT Wednesday Oct 21 2020
Short Term - Now through Thursday
KBRO doppler radar has remained fairly quiet across Deep South Texas early this morning. Do expect a slight uptick in shower activity to occur as the morning progresses as weak mid-level troughing persists over the region and boundary layer moisture continues to increase. Shower/thunderstorm activity should continue into the afternoon hours, but overall remain fairly isolated, with generally light rainfall amounts through the day. Best chances are expected to remain along and east of I-69C/US-281. After a brief lull in Probability of Precipitation this evening, isolated shower/thunderstorm chances will increase again through the morning on Thursday before ridging caps chances during the afternoon hours. Once again, best Probability of Precipitation will be east of I-69C/US-281.
With the influence of a mid-level trough overhead and scattered cloud cover in the area, decreased temperatures a couple of degrees from the previous forecast package for today and Thursday, specifically across the central and western portions of the CWA. Latest GFS/NAM/ECM MOS guidance have fairly consistent temperatures both today and tomorrow with highs generally in the upper 80s to lower-mid 90s, east to west respectively. Tonight's lows will remain on the mild side, upper 60s across the ranchlands to lower 70s across the RGV.
A strengthening easterly fetch across the Gulf will lead to slightly higher period swell that will push towards the lower Texas Coast today and especially this evening/tonight. Similar to last night, these swells combined with tides at their astronomical peak for autumn could result in some minor coastal flooding again tonight. Forecasted water levels are once again expected to reach around 1.4 ft MHHW tonight at high tide, which occurs at 11:34pm tonight. A Coastal Flood Advisory has been issued from 7pm this evening until 4am Thursday.
Long Term - Thursday Night through Tuesday
A modest short wave trough will reside over East Texas Thursday night, slowly moving east through Friday. Modest ridging will thence build over Central Mexico with a fairly flat profile over the CWA. High pressure will extend north to south from Canada to Texas, with a weak front draped across the center of the state on Friday. The front could edge into the CWA on Saturday but with limited effect. A few coastal showers will be possible, but kept chances low and with silent mention. Surface high pressure will slide east on Sunday even while interacting weakly with broad low pressure over the Western Caribbean. Winds on Sunday will veer to southeast once more and temperatures will increase several degrees with a return of warmer air from the south.
Complicating matters in the long term will be a cold front set to arrive Monday night. Canadian cP air will plunge south into Texas on Sunday and Monday, moving through the CWA Monday night and reaching the coast Tuesday around dawn. The ECMWF (European Centre for Medium-Range Weather Forecasts) develops a deeper cutoff low over the far Southwest, which effectively retards and weakens the front. The biggest effect will be temperatures, which drop significantly below normal in both models' guidance numbers, but with a bigger decrement, by about 10 degrees, in the GFS on Wednesday. In either case, an overrunning scenario will develop until the cutoff low fills and trundles east through mid week. Undercut the blends a bit on temperatures behind the front, not going quite as low as the more extreme GFS, but can see later forecasts potentially edging lower if the solution continues to trend toward the current GFS.
MARINE: Now through Thursday...High pressure across the Mid- Atlantic region and low pressure across the Yucatan will continue to produce an easterly fetch across the Gulf of Mexico and will build seas and swell through the day today. These relatively energetic waves will peak late this evening and into the overnight hours before decreasing through the morning on Thursday. Wave heigheights are expected to reach between 5 and 7 feet across the offshore waters tonight. Operators of small craft will need to exercise caution this evening if out on the offshore waters. The overall pressure gradient will remain fairly weak over the coastal waters, with light-moderate winds backing from the southeast towards the east later this morning and remaining light to moderate out of the east through the day on Thursday.
Thursday night through Sunday night...An east fetch will persist into Thursday night due to the interaction of prevailing high pressure with broad low pressure over the Western Caribbean. High pressure pushing into the Northwest Gulf Friday into Saturday will bring northeast winds and may tend to disrupt the fetch over the West Gulf, but east winds appear to persist over the East Gulf, with at least some swell component continuing locally. Southeast to south winds are expected to return on Sunday as high pressure shifts east. Winds and seas will generally remain moderate during the period. Small craft advisory conditions appear unlikely.
NOAA Brownsville TX Office: Watches - Warnings - Advisories
TX...Coastal Flood Advisory from 7pm this evening to 4am CDT Thursday for TXZ256-257-351.