textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 613 AM CDT Mon Sep 14 2026

- A Heat Advisory and Special Weather Statement (SPS) are in effect from 11 AM to 6 PM Monday. See discussion below for further details.

- Widespread extreme risks of heat-related illnesses (level 4/4) prevail on Monday, gradually improving from a major (level 3/4) and extreme risk on Tuesday and Wednesday to a mainly moderate (level 2/4) risk by Thursday.

- Fire weather concerns continue, most concerning Tuesday afternoon.

- Mostly dry conditions are expected through midweek, followed by region-wide low to medium chances of rain later in the week, peaking as high as 60% on Thursday, followed by low (15-30%) chances over the weekend.

- A low risk of life-threatening rip currents continues through Monday afternoon.

DISCUSSION

Issued at 1030 PM CDT Sun Sep 13 2026

Aside from a low (15-30%) chance of brief and isolated showers and a thunderstorm or two across the lower RGV late tonight and again across the lower and mid RGV on Wednesday afternoon, dry and breezy conditions with near record heat continue as nearly widespread inland highs soar into the triple digits through midweek, hottest across the Rio Grande Plains, where mid/upper 100s (106-108+ F) are expected, courtesy of a high pressure aloft shifting and building eastward to the eastern CONUS. Meanwhile, elevated moisture content on Monday from a departing weak mid/upper level shortwave trough leads to another day of widespread extreme risks of heat-related illnesses on Monday and a Heat Advisory is in effect for the inland and coastal portions of Cameron, Willacy and Kenedy counties from 11 AM to 6 PM for heat indices up to 111-114 F while SPSs are in effect elsewhere for indices of 108-111 F during roughly the same timeframe. The barrier islands are excluded from both the advisory and SPS. Otherwise, drier air resumes Monday night, leading to mostly major heat risks across the region on Tuesday and Wednesday, though extreme risks continue across portions of the RGV and the Rio Grande Plains; SPSs for heat indices as high as 111 F are still possible on Tuesday and Wednesday.

Additionally, daily fire weather concerns continue through at least the middle of the week as well, particularly during the afternoon hours as breezier conditions (southeasterly winds gusting to 25-35+ mph) coincide with minimizing relative humidity values. At this time, Tuesday afternoon looks to be of the greatest concern, though sustained 20 ft winds may be just beneath Fire Danger Statement criteria. Nonetheless, you can always visit weather.gov/bro/ for the latest details and tips regarding dangerous heat and fire weather.

A bit of a weather change remains in the forecast for the later half of the week. A westward-moving upper level low retreats the high pressure aloft back to the Southern Plains and a surge of surface high pressures spills southwestward from the East Coast to the Gulf, pushing a large area of deep Gulf moisture across deep south Texas out ahead of it, delivering a region-wide low to medium (30-60%) chance of rain on Thursday and a low to medium (30-40%) chance on Friday, with the best chances along/east of US-281 on both days. Any convection that develops has the potential to produce heavy rain, particularly on Thursday when PWAT values peak as high as 2.0-2.3+ in. Drier air filters in behind the pulse of moisture over the weekend, yet increased cloud coverage, low (15-30%) chances of rain and northeasterly to easterly winds are anticipated to improve risks of heat-related illnesses to a mostly moderate risk by Thursday, with highs mainly in the upper 90s (lower 100s across the Rio Grande Plains) and heat indices around 102-111 F before possibly giving way to a warming trend with deteriorating heat risks towards the end of the weekend. SPSs for heat are still possible on Thursday and later in the weekend.

Although a low risk of rip currents continues through Monday afternoon and likely over the next few days, there is the possibility of heightened rip currents risks towards the end of the week as a longer period swell arrives with slightly elevated seas.

AVIATION

(12Z TAFS) Issued at 613 AM CDT Mon Sep 14 2026

VFR conditions are expected to generally prevail through the TAF period with a southeast breeze this afternoon. There is a very low chance of a thunderstorm mid to late morning into early afternoon with confidence too low in any CB within RGV aerodromes.

MARINE

Issued at 1030 PM CDT Sun Sep 13 2026

Moderate to fresh southeasterly winds are expected and periods of Small Craft Exercise Caution (SCEC) conditions are possible through Tuesday, transitioning to gentle to moderate easterly to northeasterly by Wednesday. Slight to moderate (2-4 ft) seas build to moderate (3-5 ft) towards the later part of the week as a surge of high pressure over the Gulf pushes swell towards the Lower Texas Gulf coastal waters, when SCEC and, or a Small Craft Advisory become possible. Otherwise, low to medium (20-40%) chances of rain tonight diminish Monday into Tuesday before increasing again on Wednesday to as much as a medium to likely (50-70%) chance on Thursday. Chances of rain gradually drop to a low (15-30%) chance over the weekend.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 97 81 98 79 / 10 0 0 0 HARLINGEN 101 78 102 76 / 10 0 0 0 MCALLEN 103 81 104 79 / 0 0 0 0 RIO GRANDE CITY 104 79 105 77 / 0 0 0 0 SOUTH PADRE ISLAND 90 82 90 82 / 10 0 0 0 BAYVIEW/PORT ISABEL 96 79 97 78 / 10 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory from 11 AM this morning to 6 PM CDT this evening for TXZ251-254-255-351-354-355.

GM...None.