Marine Weather and Tide Forecast for Port Mansfield, TX

DISCUSSION
Issued at 1200 PM CST Sun Nov 9 2025

The much anticipated cold front has swept across Deep South Texas as of earlier this morning, with breezy northerly winds ushering a notably drier and cooler airmass in its wake. Post-frontal stratus clouds have developed, and are expected to persist through at least the mid afternoon hours before clearing out. While many are looking forward to below normal temperatures to start the work week, we'll have to contend with hazardous marine, beach, and fire weather conditions through at least tomorrow evening. There may be a brief period tonight into tomorrow morning where a Coastal Flood Statement/Advisory may be needed as we approach high tide.
Otherwise, temperatures this afternoon should remain mostly in the 70s, although a few areas across the Northern Ranchlands may fall into the upper 60s due to persistent cold air advection.

Low temperatures tonight will range from the mid 40s across the Northern Ranchlands to low 50s across the Rio Grande Valley. A tight pressure gradient will keep northerly winds elevated tonight, which will result in apparent temperatures closer to the upper 30s and low 40s across the Northern Ranchlands to around 50 degrees across the Rio Grande Valley. As persistent cold air advection continues into Monday via brisk northerly winds and wind gusts, opted to bump high temperatures slightly lower by 1-3 degrees across the Rio Grande Valley and along the Lower Texas beaches, with most areas realizing high temperatures in the upper 60s to low 70s. Efficient radiational cooling processes will set up Monday night into Tuesday morning region wide as winds become light and skies remain generally clear. Low temperatures will likely dip into the upper 30s and low 40s across the Northern Ranchlands and Mid/Upper RGV, and closer to the mid 40s across the Lower RGV.

Low level southerly to southeasterly flow returns by Tuesday, marking the start of warming trend through the rest of the week.
Guidance indicates an upper level trough and attendant surface low will dig into the Plains by the weekend.

AVIATION
(00Z TAFS)
Issued at 531 PM CST Sun Nov 9 2025

VFR conditions are expected to continue through the TAF period.
Northerly winds will likely persist through the period. Wind gusts have recently begun to drop off across most inland areas, remaining more frequent near the coast. However, model guidance continues to show additional wind gusts overnight and into the day Monday at all three TAF sites.

MARINE
Issued at 1200 PM CST Sun Nov 9 2025

Hazardous marine conditions will prevail through at least Monday afternoon/evening over the Gulf waters and Laguna Madre in wake of the passage of a cold front this morning. A Gale Warning is in effect through 06Z Monday over the Gulf waters, but may need to be extended to 12Z Monday. A Small Craft Advisory is in effect through 18Z Monday across the Laguna Madre, and a Small Craft Advisory will likely be issued for the Gulf waters from 12Z Monday through 18Z Monday due to the combination of winds around 20-30 knots and seas of 10-12 feet. There should be improvement by Monday evening as the pressure gradient weakens, with generally favorable marine conditions by Tuesday. Small Craft Exercise Caution to Small Craft Advisory conditions return on Wednesday and once again over the weekend.

FIRE WEATHER
Issued at 1200 PM CST Sun Nov 9 2025

The passage of a strong cold front will bring increased fire weather concerns through this evening, and once again Monday afternoon, across most of Deep South Texas. This is due to the combination of a notably drier airmass filtering in, breezy north winds, and dry fuels.

A Red Flag Warning remains in effect through this evening across Zapata, Jim Hogg, Brooks, and Inland Kenedy counties as afternoon relative humidity values fall below 25% and 20-foot winds range from 15-20 MPH. A Fire Danger Statement is in effect for the rest of Deep South Texas, as relative humidity values remain slightly higher and 20-foot winds remain slightly lower.

Although relative humidity values are expected to be lower on Monday, with values ranging from 15-30%, 20-foot are expected to range from 5-10 MPH along and west of I-69E and closer to 10-15 MPH along and east of I-69E. A Red Flag Warning likely will not be issued, but a Fire Danger Statement may be warranted given the dry fuels and potential for occasional higher gusts.

PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 56 68 49 78 / 0 0 0 0 HARLINGEN 50 68 44 79 / 0 0 0 0 MCALLEN 52 70 47 80 / 0 0 0 0 RIO GRANDE CITY 48 70 40 80 / 0 0 0 0 SOUTH PADRE ISLAND 59 67 56 75 / 0 0 0 0 BAYVIEW/PORT ISABEL 57 67 49 77 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES
TX...Red Flag Warning until 9 PM CST this evening for TXZ248>251.

High Rip Current Risk through Monday afternoon for TXZ451-454- 455.

High Surf Advisory until 6 PM CST Monday for TXZ451-454-455.

GM...Small Craft Advisory until noon CST Monday for GMZ130-132-135.

Gale Warning until 6 AM CST Monday for GMZ150-155-170-175.