textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 615 AM CDT Sun Aug 16 2026

- A Special Weather Statement (SPS) is in effect for Southern Hidalgo County as well as the inland portions of Cameron, Willacy and Kenedy counties on Sunday, where heat indices are likely to reach around 108-111 F for several hours.

- A mostly moderate risk of heat-related illness (level 2/4) escalates to a mostly major risk (level 3/4) by next Thursday.

- Conditions remain mostly dry, except for a low (15-30%) chance of rain for the lower and mid RGV on Monday.

- The combination of low afternoon relative humidity coinciding with breezy to gusty conditions leads to fire weather concerns, especially Tuesday through Friday.

- A medium risk of life-threatening rip currents continues through Sunday afternoon.

DISCUSSION

Issued at 1016 PM CDT Sat Aug 15 2026

A rather robust high pressure aloft shifts west over the Southern Plains on Sunday, migrating to the Desert Southwest by the early parts of next week. Aside from a weak inverted trough passing over the region on Monday, bringing a daytime low (15-30%) chance of rain to the lower and mid RGV, peaking in the afternoon, elevated subsidence and heights aloft should otherwise maintain dry conditions into next weekend.

In the meantime, a SPS is in effect for Southern Hidalgo County in addition to the inland portions of Cameron, Willacy and Kenedy counties on Sunday as moisture increasing ahead of the trough leads to heat indices of around 108-111 F, generally within the hours of 12 PM to 6 PM. Otherwise, flattening of the high pressure's associated ridge aloft is likely to loosen the pressure gradient just a bit, with southeasterly surface winds gusting to near 20-30 mph (as opposed to 25-35+ mph this past week); this should help retreat highs in the low/mid 100s to along/west US-281/I-69 C, warmest across the Rio Grande Plains into at least Monday. Additionally, maximum heat indices of 105-110+ F across Deep South Texas are expected to lead to mainly moderate risks of heat- related illnesses (heat risks) into next Tuesday, though more urban areas of the RGV and Rio Grande Plains may remain at a major risk.

Despite slightly weaker onshore flow, much drier moisture content from sinking air behind the trough is likely to allow nearly widespread low/mid 100s to return by next Tuesday, warming by a few degrees into the remainder of the week. Heat risks are anticipated to worsen from moderate to major on Wednesday to mostly major by Thursday as onshore southeasterly winds re-enhance in response to a a developing mid/upper level trough moving over the Plains, thus elevating moisture and PWAT values slightly, though still remaining drier to near average for this time of year. Thus, the combination of lower afternoon relative humidity values, minimizing around 20-50 percent, coinciding with breezy to gusty conditions, continues to pose a risk of fire weather and Fire Danger Statements are possible, particularly Tuesday through Friday. Depending on moisture trends, additional SPSs for 108-111 F heat indices may be issued as well, especially for the later half of the week.

A medium risk of rip currents continues through Sunday afternoon.

AVIATION

(12Z TAFS) Issued at 615 AM CDT Sun Aug 16 2026

VFR will prevail at the aerodromes through the next 24 hours. Light winds for the overnight hours will become moderate for the daytime with breezy gusts. No precipitation is forecast or expected at this time.

MARINE

Issued at 1016 PM CDT Sat Aug 15 2026

Gentle to moderate easterly to southeasterly winds and slight to moderate seas (2-4 ft) become southeasterly to southerly on Monday, enhancing back to moderate to fresh with periods of Small Craft Exercise Caution conditions and moderate (3-5 ft) seas by next Wednesday. Outside of a low (15-30%) chance of showers and a few thunderstorms on Sunday and a low to medium (20-40%) chance on Monday, conditions are anticipated to remain mostly dry though a brief shower is possible from time-to-time.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 96 80 96 80 / 0 10 20 0 HARLINGEN 99 76 99 76 / 0 0 20 0 MCALLEN 103 80 102 79 / 10 0 30 0 RIO GRANDE CITY 103 78 102 77 / 0 0 10 0 SOUTH PADRE ISLAND 89 81 89 81 / 0 10 10 0 BAYVIEW/PORT ISABEL 94 79 94 78 / 0 0 10 0

BRO WATCHES/WARNINGS/ADVISORIES

None.