textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 114 PM CDT Wed Jul 8 2026

* Hot summer conditions continue through the week. Moderate (level 2 of 4) Heat Risk each day, mainly in the Valley becoming more widespread this weekend. Heat indices will climb to between 100 and 110 degrees each day.

* Daily rain and thunderstorm chances will increase from 10-25% Wednesday/Thursday to 25-40% Friday/Saturday. While severe weather is not expected, any storms that develop are capable of heavy to torrential rainfall, gusty winds and small hail. * There is generally a low risk of rip currents at area beaches likely increasing to moderate this weekend.

DISCUSSION

Issued at 114 PM CDT Wed Jul 8 2026

Our region is currently sandwiched between an area of upper level low pressure across Central Mexico and another area of upper level low across the Tennessee and Mississippi Valley. In other words, Deep South Texas is situated within a narrow corridor of upper level ridge. Latest suite of hi-res and global guidance remain in agreement that the generally benign weather should continue through Thursday morning, with shower and thunderstorms coverage remaining isolated to widely scattered and transient in nature. Earlier this morning, composite radar and visible satellite shows an area of disorganized convection moving northwards from Tamaulipas and falling apart as it approaches the international border. Surface obs also indicate drier air from the top of the boundary layer mixing down, with mostly to partly sunny skies prevailing away from the coast and dew points falling into the low 70s from upper 70s.

PWAT values are about 1.8 inches, which is around the 75th percentile of SPC sounding climatology for our area. While there is negligible shear to get storms organized, any storms that do develop is capable of locally heavy downpours, gusty winds and even small hail. Otherwise, chance of showers and thunderstorms increase from 10-25 percent today/Thursday to 25-40 percent for Friday/Saturday. This is because a surge of tropical moisture looks to approach our region from the southeast by Thursday and certainly into Friday. PWATs increase to between 2 to 2.2 inches, which is 90-95th percentile of sounding climatology for the Brownsville, TX upper air site. Currently, there are no excessive rainfall outlooks from WPC for our area due to low confidence in flash flooding but this is something to monitor in the coming days. 1-hour Flash Flood Guidance across the RGV is quite high, with 2.5 to 3.5 inches per hour according to WGRFC owing to the fact that it has been over three weeks since our last widespread rainfall.

One thing to note is that while the official forecast might indicate a lack of area wide significant rainfall, such an environment is capable of producing highly efficient rainfall rates with locally quick couple of inches of rainfall in just 30 to 45 minutes. It is almost impossible to pinpoint exactly where ahead of time, however, given the isolated to widely scattered nature of the showers and thunderstorms. In the absence of shear, the main triggers for locally heavy rainfall and isolated storms will be the sea breeze and local outflow boundaries, which can be quite messy in a weakly forced environment. Bottom line, if you do have outdoor plans, please keep an eye to the sky and be ready to go indoors if thunder roars. Drier weather looks to return for Sunday into early next week. Early indications are that rain chances would increase towards middle part of next week as a cold front approaches from the north but confidence is low this far out. Looking at the CPC 6-10 day outlook, there is a 40-50 percent probability of above normal rainfall and 33-50 percent probability of above normal temperatures for our CWA.

Typical mid-summer temperatures into the mid to upper 90s for most inland locations continue, with a cooler beach and warmer brush country. Expect a Moderate (level 2 of 4) Heat Risk through much of the forecast period, with brief relief where clouds, showers, or thunderstorms can develop. Combined with the oppressive humidity with dew points in the mid to upper 70s, heat index values are expected to top out in the 105-110 range away from the coast.

Long period swell increases into the weekend and early next week offshore, potentially bringing a Moderate Risk of life-threatening rip currents along the lower Texas coast. Astronomical tides build this weekend as we near the New Moon, which may narrow already narrow beaches at high tide cycles this weekend into next week.

AVIATION

(00Z TAFS) Issued at 621 PM CDT Wed Jul 8 2026

VFR conditions expected to prevail through the 00Z TAF cycle. Gusty winds to 25 kts this evening diminish following sunset. Winds increase yet again late Thursday morning, with southeasterly gusts 20-25 kts. Thursday afternoon, isolated showers and thunderstorms heading west/northwest with heavy rain and lightning are possible along the seabreeze. This may temporarily reduce visibility and ceiling heights to MVFR to LIFR if any showers pass over a site.

MARINE

Issued at 114 PM CDT Wed Jul 8 2026

Light to moderate south-southeasterly winds continue across the coastal waters through most of the forecast period with strong high pressure northwest of the Gulf. The only exception will be during periods of thunderstorms, where brief periods of strong wind gusts along with locally heavy rainfall will be possible especially during the afternoon hours. Expect an afternoon chop each day on the bay, with Gulf seas of generally 2 to 3 feet, gradually building towards 3 to 4 feet late this weekend into next week with longer period swells.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 78 93 79 93 / 0 20 30 30 HARLINGEN 75 94 76 94 / 0 20 20 30 MCALLEN 77 97 79 97 / 0 20 10 30 RIO GRANDE CITY 76 97 77 97 / 0 20 0 30 SOUTH PADRE ISLAND 80 87 81 87 / 0 30 40 40 BAYVIEW/PORT ISABEL 77 91 78 91 / 0 20 30 30

BRO WATCHES/WARNINGS/ADVISORIES

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