Marine Weather Net

Port Mansfield, TX to the Rio Grande River Marine Forecast


TODAY

SE
WINDS
15 - 20
KNOTS

TONIGHT

SE
WINDS
20
KNOTS

THURSDAY

SE
WINDS
15 - 20
KNOTS

THURSDAY NIGHT

SE
WINDS
15 - 20
KNOTS

The Marine Weather Forecast In Detail:
GMZ150 Forecast Issued: 420 AM CDT Wed Jul 08 2020

Today...Southeast Winds 15 To 20 Knots. Seas 3 To 5 Feet.
Tonight...Southeast Winds Around 20 Knots. Seas 3 To 5 Feet.
Thursday...Southeast Winds 15 To 20 Knots. Seas 2 To 4 Feet.
Thursday Night...Southeast Winds 15 To 20 Knots. Seas 2 To 4 Feet.
Friday...Southeast Winds 15 To 20 Knots. Seas 2 To 4 Feet.
Friday Night...Southeast Winds Around 15 Knots. Seas 2 To 3 Feet.
Saturday...Southeast Winds 10 To 15 Knots. Seas 2 To 3 Feet.
Saturday Night...South Winds 15 To 20 Knots. Seas 2 To 3 Feet.
Sunday...South Winds 15 To 20 Knots. Seas 2 To 3 Feet.
Sunday Night...South Winds 15 To 20 Knots. Seas 3 To 4 Feet.
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Synopsis for Baffin Bay to Rio Grande out 60 nm: GMZ100
420 AM CDT Wed Jul 8 2020

Pressure gradient strengthens today and Thursday as low pressure emerges from the Rockies and crosses the Southern and Central Plains. This will produce stronger onshore flow with adverse marine conditions today, tonight and Thursday. High pressure strengthens Friday and for the weekend with winds diminishing to more moderate levels. Seas to respond to the increase in winds with subsiding seas into the weekend. No rain is anticipated.
Area Forecast Discussion
National Weather Service Brownsville TX
400am CDT Wednesday July 8 2020

Short Term - Now through Thursday
500mb ridge centered over the Desert SW and NW Mexico begins to build and expand eastward through the short term and beyond. The atmosphere AOA 850mb across Deep South Texas remains relatively dry and models indicate further drying Thursday as subsidence increases. Southerly flow strengthens today and Thursday as a mid-layer low pressure trough emerges over the Rockies and tracks over the Plains. GFS is the strongest with boundary layer winds at around 25 knots between 925-850mb. Combine this with the strengthening thermal gradient and late morning and afternoon conditions should become windy with gusts nearing or exceeding 35 mph but remain shy of wind advisory. Temperatures continue hot, 2-4 degrees above normal today and 3 to 5 degrees, Thursday with just enough daytime mixing of the drier air aloft to lower dew points keeping heat indices at bay and below heat advisory levels. Overnight lows for Thursday morning not so low with sultry upper 70s to lower 80s.

Long Term - Thursday Night through Tuesday
The large-scale pattern will remain similar through the long term period with very hot conditions continuing to be the main message. 500mb high pressure will build over NM/TX, leading to a possible major heat wave event across the Central and Southern Plains. Across Deep South Texas, daily highs and lows will be above normal and will gradually warm into the weekend. Model guidance indicates possible Heat Advisories through the weekend due to the combination of elevated humidity and hot ambient temperatures. Though we will likely see efficient dry air mixdown each afternoon, heat indices may range from 111 to 115 in a few areas. By early next week, even drier air moves into the region, so heat indices should stay below advisory criteria. With a very dry atmosphere from 850mb through 300mb, rain chances remain very low at 5% or below each day.

Marine - Now through Thursday
Pressure gradient strengthens later today into Thursday as pressures lower over NW Texas. Winds increase over the Laguna Madre and are likely to reach Small Craft Advisory levels for this afternoon and possible again Thursday. Winds offshore approach the 20 knot criteria today but are more likely to reach small craft advisory levels tonight as mid-level low pressure moves across the Plains. Seas remain steady state today and may bump up a foot overnight into early Thursday.

Thursday night through Tuesday: A moderately strong pressure gradient will keep winds elevated each day across the nearshore waters, thanks to high pressure over the Gulf and lower pressure across interior Mexico and into the High Plains. Small craft will need to exercise caution each afternoon across the bay and nearshore waters. Winds may periodically touch advisory levels late in the period with models showing a slightly stronger low level jet developing Monday into Tuesday.

NOAA Brownsville TX Office: Watches - Warnings - Advisories
TX...None. GM...Small Craft Advisory from 1pm this afternoon to 9pm CDT this evening for GMZ130-132-135.