textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 604 AM CDT Tue Jul 21 2026

- Daily above average and record breaking/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).

- A Special Weather Statement (SPS) is in effect for the coastal and inland portions of Cameron, Willacy and Kenedy counties, excepting the barrier islands, from 11 AM to 7 PM Tuesday for heat indices of 108 to 111 F, potentially briefly higher. Additional SPSs or heat advisories are possible this week.

- Lower relative humidity and, at times, breezy southeasterly winds continue an enhanced risk of wildfire spread and Fire Danger Statements (RFDs) are possible.

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

- A low risk of life-threatening rip currents continues through Tuesday 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 1016 PM CDT Mon Jul 20 2026

A 594+ dam high pressure aloft over the Rocky Mountains slips southeastward to the Southern Plains on Tuesday, increasing to 597+ dam by Thursday before retreating to the Desert Southwest over the weekend, but may progress eastward or stretch back to the Southern Plains again by early next week. Overall, this spells out continued above average and near record heat as well as breezy and mainly dry conditions, with temperatures maximizing around 100 to 107+ F across nearly all inland areas of deep south Texas into early next week. The next 2 days could feature the hottest air temperatures, with mid/upper 100s along/west of US-281 on Tuesday expanding to along/west of I-69 E on Wednesday. Following, highs in the low/mid 100s (100 to 106 F) are anticipated. In general, moderate to major heat risks persist as afternoon heat indices range around 105 to 111+ F. Additionally, lighter southeasterly wind speeds are likely for the remainder of the forecast, which lessens the chance of RFD criteria being met, but lower relative humidity from high pressure aloft and breezy afternoon/evening conditions, gusting to as much as 30 mph, still run an enhanced risk for wildfire spread and an abundance of caution is urged when handling flames due to dry or normal fuels across the region. Nonetheless, RFDs still remain possible into early next week.

In the meantime, a SPS is in effect from 11 AM to 7 PM Tuesday for the inland and coastal portions of Cameron, Willacy and Kenedy counties for heat indices of 108 to 111 F, possibly reaching a few degrees warmer briefly. Additional SPSs and heat advisories remain possible through the forecast period.

Tropics-wise, we continue to monitor Tropical Storm Bertha, currently situated offshore the Florida Panhandle and slowly moving to the northwest, with sustained winds of around 40 mph. NHC still projects a westward turn towards coastal Louisiana by Wednesday and potentially weaken to a tropical depression later this week as it progresses along its westward track into this weekend, possibly remaining over the northern Gulf or slightly inland. Although much of our CWA is within the southern end of the cone of uncertainty at this time, no major impacts are expected across deep south Texas. Yet, there still exists a wide range of potential outcomes and will be monitored closely. At the very least, cloud coverage could increase Wednesday night into Thursday, bringing, at most, a low (15-30%) chance of rain during the daytime on Thursday, highest closer to the coast. Yet, again, forecast confidence remains very low and highly subject to change over the next couple of days. A low risk of life-threatening rip currents continues through Tuesday 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 appearance amidst sweltering temperatures and mainly sunny skies.

AVIATION

(12Z TAFS) Issued at 604 AM CDT Tue Jul 21 2026

VFR conditions are generally expected to prevail through the TAF period with breezy southeasterly winds by mid morning persisting into early this evening.

MARINE

Issued at 1016 PM CDT Mon Jul 20 2026

Gentle to moderate southeasterly winds, occasionally fresh, with slight to moderate (2-4 ft) seas are expected to continue though could increase later in the week, dependent on any swell that develops from Tropical Storm Bertha, situated offshore the Florida Panhandle, moving northwestward. We currently anticipate a low to medium (20-40%) chance of rain late Wednesday night into Thursday morning before gradually decreasing thereafter and diminishing Thursday night. However, confidence is low and uncertainty is high to the forecast by the later parts of this week and will be dependent on the track and intensity of the tropical storm as NHC projects Bertha taking on a track to the west by the middle of the week and possibly weakening back to a tropical depression later in the week, potentially lingering near the northern Gulf coast or slightly inland.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 98 78 100 79 / 0 0 0 0 HARLINGEN 104 74 104 76 / 0 0 0 0 MCALLEN 107 77 107 78 / 0 0 0 0 RIO GRANDE CITY 107 75 107 78 / 0 0 0 0 SOUTH PADRE ISLAND 88 79 89 80 / 0 0 0 0 BAYVIEW/PORT ISABEL 97 76 97 77 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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