textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 617 AM CDT Tue Mar 10 2026

Key Messages:

- Unseasonably warm temperatures are expected through mid-week, with wind speeds picking up Tuesday due to a tightened pressure gradient.

- There is a low (20%) chance for showers and thunderstorms Tuesday night ahead of a cold front.

- A stronger front Wednesday night will likely bring more seasonable temperatures Thursday and Friday.

- Temperatures will be unseasonably warm again by the weekend, with no rain expected.

DISCUSSION

Issued at 1042 PM CDT Mon Mar 9 2026

A cold front is forecast to move through Deep South Texas Tuesday night into Wednesday morning, with a secondary front arriving Wednesday night. A line of convection will likely develop along the frontal boundary Tuesday as it moves across Central Texas, with uncertainty on how far south this line may extend Tuesday evening. The latest probabilistic guidance has rain chances around 20-30% for the western third of the CWA Tuesday night. The latest HiRes model guidance keeps the majority of the convection north of the CWA Tuesday evening/night, though the 0z run of the HRRR does have a few showers or thunderstorms clipping the northwestern portion of the CWA early Tuesday night.

With the timing of the front likely overnight, instability will likely be decreasing in advance of the front, which will likely decrease the potential for convection to develop or be sustained along the front. However, ample wind shear ahead of the front could support strong, but likely sub-severe, thunderstorms if any convection is able to sustain itself overnight.

Temperatures behind this initial front will remain hot Wednesday, with highs likely remaining in the low to mid 90s. However, this air mass will be much drier which will likely allow relative humidity values to fall to the teens to low 20s Wednesday afternoon. Wind speeds will likely remain low enough Wednesday afternoon to limit fire weather concerns.

The stronger front Wednesday night will likely allow high temperatures to fall to the upper 70s to low 80s Thursday, before gradually returning to the 90s over the weekend. Stronger winds through the later half of the week and relative humidity values between 20-30% could pose a risk for elevated fire weather conditions Thursday and Friday.

AVIATION

(12Z TAFS) Issued at 617 AM CDT Tue Mar 10 2026

Most TAF sites are already seeing VFR conditions occurring, and are likely to persist through the rest of the daytime and evening hours. Winds are expected to be out of the southeast and could even gust up to 30 knots. By the evening, the winds should weaken a bit, but gusts could still get up to 25 knots. The overnight hours could see some MVFR conditions return.

MARINE

Issued at 1042 PM CDT Mon Mar 9 2026

Tightening pressure gradients ahead of a cold front will likely result in stronger southeasterly winds Tuesday afternoon, likely requiring Small Craft Should Exercise Caution headlines or Small Craft Advisories for the Laguna Madre and nearshore Gulf waters. Conditions will likely briefly improve Tuesday night into Wednesday morning as the first of tow cold fronts move through the region. However, stronger northerly winds in the wake of the second front Wednesday night will likely result in another round of hazardous marine conditions likely requiring Small Craft Advisories for the Laguna Madre and Gulf waters.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 87 72 93 63 / 0 0 0 0 HARLINGEN 90 70 94 57 / 0 10 0 0 MCALLEN 93 73 97 62 / 0 10 0 0 RIO GRANDE CITY 95 69 94 61 / 0 20 0 0 SOUTH PADRE ISLAND 79 72 84 66 / 0 0 0 0 BAYVIEW/PORT ISABEL 86 70 90 62 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...None.