textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 130 PM CDT Sat Aug 8 2026

- Low chances of rain (20-30%) continue along the afternoon and early evening seabreeze boundary through Monday.

- The combination of hot temperatures and humidity will result in triple-digit heat index values each afternoon.

DISCUSSION

Issued at 130 PM CDT Sat Aug 8 2026

The main weather story heading into the second week of August is the summertime heat across Deep South Texas as the region remains under the influence of high pressure aloft. However, weak embedded disturbances translating along the periphery of the ridge will interact with the presence of high moisture content and diurnal instability this weekend and into at least Monday, resulting in enhanced sea breeze activity each day. Showers and thunderstorms should be fairly short-lived, but brief heavy rainfall, gusty winds, and lightning will be possible. Through the weekend, expect highs ranging from the mid 90s along the immediate coast to around 102 degrees across the Rio Grande Plains, with heat indices ranging from 105-110 degrees.

Ridging aloft starts to build once again by early next week, which should result in triple-digit high temperatures each afternoon along and west of the I-69E corridor. In combination with elevated humidity, heat index values are expected to approach Heat Advisory criteria (heat indices above 111 degrees) across portions of the region. Otherwise, expect breezy southerly to southeasterly winds during the afternoon hours by mid week as the pressure gradient tightens, with gusts up to 25-30 MPH.

AVIATION

(18Z TAFS) Issued at 130 PM CDT Sat Aug 8 2026

VFR will prevail through most of the forecast period, although intermittent MVFR ceilings cannot be ruled out late tonight into early tomorrow morning. Isolated convection along the sea breeze may result in brief heavy rain, reduced visibility/ceilings, gusty winds, and lightning this afternoon. Otherwise, expect southerly winds around 10 knots this afternoon before becoming calm to light and variable tonight into tomorrow morning.

MARINE

Issued at 130 PM CDT Sat Aug 8 2026

Generally favorable marine conditions will prevail with light to moderate southerly to southeasterly winds and low to moderate seas. Brief Small Craft Exercise Caution conditions cannot be ruled out for the nearshore waters and Laguna Madre during afternoon hours each day in response to an enhanced pressure gradient. Otherwise, expect low to medium rain chances (20-40%) through Monday evening before coming to an end for the remainder of the week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 79 94 80 96 / 0 30 0 10 HARLINGEN 75 96 76 99 / 0 30 0 10 MCALLEN 79 100 80 102 / 10 20 0 0 RIO GRANDE CITY 77 99 77 102 / 10 10 0 0 SOUTH PADRE ISLAND 79 88 81 89 / 10 30 10 10 BAYVIEW/PORT ISABEL 77 93 78 95 / 10 20 0 10

BRO WATCHES/WARNINGS/ADVISORIES

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