textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 520 AM CDT Wed Jul 22 2026

- Daily above average and record breaking or tying temperatures, maximizing around 100 to 107+ F, with heat indices of 105 to 111+ F, continue moderate to major heat risks (levels 2/4 and 3/4), possibly becoming mostly major with pockets of extreme heat risks (level 4/4) early next week.

- A Special Weather Statement (SPS) is in effect for the coastal and inland portions of Cameron, Willacy and Kenedy counties, not including the barrier islands, from 12 PM to 7 PM Wednesday for heat indices of 108 to 111 F, potentially briefly higher. Additional SPSs are likely as well as possible heat advisories.

- Lower relative humidity and, at times, breezy southeasterly winds continue an enhanced risk of wildfire spread.

- We continue to monitor the tropics and updates from the National Hurricane Center (NHC) on Tropical Storm Bertha, currently located over the northern Gulf, and its potential impacts, if any, later this week.

- A low risk of life-threatening rip currents continues through Wednesday afternoon, but stay tuned for updates on the potential for increased risks of rip currents, elevated surf and minor coastal flooding possible later this week in association with Tropical Storm Bertha.

DISCUSSION

Issued at 1049 PM CDT Tue Jul 21 2026

As has been the ongoing weather pattern, a 494-497+ dam high pressure aloft is anticipated to linger over the Southern Plains into early next week. Aside from a low to medium end chance of rain Thursday and Thursday night, discussed further below, dry and, at times, breezy conditions continue across deep south Texas along with daily above average, record breaking or tying heat. Wednesday could feature the hottest high temperatures, likely maximizing in the low/mid 100s along/east of I-69 E, while all locations to the west experience mid/upper 100s. Following, inland highs are anticipated to range around 100-106 F, potentially peaking around 107+ F across the Rio Grande Plains. Highs in the mid/upper 80s along and near the coast prevail. Given larger afternoon dewpoint depressions and lower relative humidity coinciding with periods of breezy southeasterly winds, generally gusting to 20-25+ mph, an enhanced risk for wildfire spread prevails and an abundance of caution is urged when handling flames due to dry or normal fuels across the region.

Once again, a SPS is in effect from 12 PM to 7 PM Wednesday for the coastal and inland portions of Cameron, Willacy and Kenedy counties as afternoon and early evening heat indices peak around 108 to 111 F and possibly higher for a brief period of time. Forecast apparent temperatures do not quite satisfy heat advisory criteria for Wednesday. However, should overnight and/or Wednesday morning guidance trend upwards, later shifts could upgrade the SPS to a heat advisory for all or portions of the SPS-outlined areas. Additional SPSs are likely into early next week as daily afternoon heat indices of around 105 to 111+ F result in moderate to major heat risks. Additional heat advisories are not out of the question, perhaps especially early next week when pulses of Gulf moisture could lead to mainly major heat risks with potential pockets of extreme heat risks.

In regards to the tropics and as of the 10 PM CDT tropical update, Tropical Storm Bertha continues to slowly move to the west over the northern Gulf, with maximum sustained winds of 60 mph. The NHC continues to project Bertha maintaining tropical storm strength along a westward track, bringing the most direct impacts to southern Louisiana/coast into the later part of this week and southeastern Texas/Upper Texas coast later this week and weekend. However, there still exists a considerable amount of uncertainty, especially for the latter half of this week into this weekend.

Meanwhile, northeasterly winds on the eastern sides of both the high pressure aloft and a surface high pressure, progged to move from the Upper Midwest to the Great Lakes later in the week, could displace some or most of Bertha's tropical moisture and convection southwestward, bringing a low (15-30%) chance of rain along/east of US-281/I-69 C during the Thursday morning and afternoon hours, increasing to a region-wide low to medium (20-40%) chance Thursday evening followed by decreasing chances Thursday night. The highest chances of rain are currently expected to reside across the Northern Ranchlands, where the latest 50th and 75th GFS and ECMWF ensemble percentiles indicate anywhere from a trace to as much as a few quarters of an inch of rain by Friday morning, which is more or less in alignment with our forecast of around 0.10-0.20 of an inch, with lesser amounts elsewhere. An increase in moisture with low chances of rain could result in a mostly major heat risk on Thursday as well as on Friday due to lingering deep moisture and subsidence behind the departing system. Yet, due to low confidence at this time, the forecast is subject to change within the next 24 to 48 hours or more.

A low risk of life-threatening rip currents continues through Wednesday afternoon. As the week progresses, potential long period swell and perhaps elevated surf, generated by Tropical Storm Bertha, could arrive to the Lower Texas coastal waters later in the week; elevated risks of life-threatening rip currents, higher surf and minor coastal flooding are possible and may lead to more dangerous beach and swimming conditions, despite the inviting Gulf appearance amidst sweltering temperatures and mainly sunny skies.

AVIATION

(12Z TAFS) Issued at 520 AM CDT Wed Jul 22 2026

VFR will continue at the aerodromes through the next 24 hours. Clear skies will dominate with moderate to breezy winds during the daytime and lighter winds at night.

MARINE

Issued at 1049 PM CDT Tue Jul 21 2026

Gentle to moderate southeasterly winds, occasionally fresh, with slight to moderate (2-4 ft) seas are expected to enhance to mostly moderate to fresh, strong at times, with moderate (3-5 ft) seas by Friday. Periods of Small Craft Exercise Caution conditions are possible, especially over the weekend and into early next week. Although the most direct impacts from Tropical Storm Bertha, moving west over the northern Gulf, are currently anticipated to remain well to the north, slightly elevated seas from associated swell could arrive to the Lower Texas coastal waters later this week and/or this weekend. Low (15-30%) chances of rain late Wednesday could increase to as much as a low to medium (20-50%) chance by Thursday morning, followed by gradually diminishing chances Thursday afternoon into Thursday night. Yet, due to the high uncertainty remaining, forecast confidence is low for the latter half of this week into the weekend and highly subject to change over the next 24- 28+ hours.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 101 79 97 80 / 0 0 20 10 HARLINGEN 106 76 100 77 / 0 0 20 20 MCALLEN 108 79 104 80 / 0 0 10 30 RIO GRANDE CITY 108 79 103 80 / 0 0 10 20 SOUTH PADRE ISLAND 90 80 88 81 / 0 0 20 10 BAYVIEW/PORT ISABEL 99 78 95 79 / 0 0 30 10

BRO WATCHES/WARNINGS/ADVISORIES

None.