textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 631 AM CDT Sat May 30 2026

* Dry and hot conditions, along with increasing relative humidity, persist into early next week, elevating a mainly minor heat risk (level 1 of 4) over the weekend to a minor to moderate heat risk (level 2 of 4) next Monday.

* Rounds of showers and thunderstorms return, bringing at least a low (15-30%) chance of rain by early next week, increasing to as much a medium (50-60%) chance of rain next Tuesday. * A moderate risk of rip currents continues through Saturday afternoon.

DISCUSSION

Issued at 1026 PM CDT Fri May 29 2026

A mid/upper level high pressure maintains subsidence over deep south Texas, steadily and slightly increasing 500 mb heights through this weekend into the early part of next week. This will lead to abundant sunshine, dry conditions and near to slightly above temperatures, maximizing in the mid/upper 90s over the Middle and Upper RGV while low/mid 90s continue elsewhere, resulting in at least a minor heat risk though portions of the RGV and coastal counties could experience a moderate risk. Meanwhile, weak surface high pressure over the eastern Gulf and weak disturbances over the western Gulf maintain a steady plume of deep and tropical moisture advection into our region via southeasterly to easterly winds, primarily picking up Saturday night. As a result of building moisture content, moderate heat risks gradually expand to cover more of deep south Texas next Monday, with afternoon heat indices of 100 to 105 F continuing into Tuesday.

The synoptic weather set-up shifts a bit in the early to middle parts of next week as ridging dives southward over the eastern US and a surface high pressure over the Great Lakes push a cold front southwestward into the Southern US, possibly stalling across the coastal Deep South. Meanwhile, troughing aloft slowly migrates eastward into Texas, thus gradually lowering 500 mb heights and easing on subsidence aloft. This, factored in with moisture pooling southwest of the frontal boundary, should foster the development of showers and thunderstorms pulsing westward into the CWA, bringing at least a low (15-30%) daily chance of rain by possibly next Monday afternoon, increasing to as much as a low to medium (30-60%) chance next Tuesday. A nightly low (15-30%) chance of rain is possible as well. The greatest chances of rain are generally expected to remain along/east of US-281. Cloud coverage should help to knock down both daytime temperatures and heat indices before drier conditions and warmer temperatures return by the end of next week.

A moderate risk of rip currents continues through Saturday afternoon.

AVIATION

(12Z TAFS) Issued at 631 AM CDT Sat May 30 2026

IFR visibilities at HRL are forecast to improve within the next couple hours. VFR conditions are forecast to continue through the day at BRO and MFE, and return at HRL by mid morning. Winds are forecast to remain easterly to southeasterly through the period. MVFR ceilings may develop tonight, with the highest probabilities occurring at MFE.

MARINE

Issued at 1026 PM CDT Fri May 29 2026

Gentle to moderate easterly to southeasterly winds and slight to moderate (2-5 ft) seas continue throughout the forecast period. Chances of rain from rounds of showers and thunderstorms begin to pick up as early as Sunday night or Monday, to as much as a medium (40-50%) chance next Tuesday.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 93 77 92 79 / 0 0 0 0 HARLINGEN 94 73 92 76 / 0 0 0 0 MCALLEN 97 76 96 78 / 0 0 0 0 RIO GRANDE CITY 97 75 96 77 / 0 0 0 0 SOUTH PADRE ISLAND 85 80 85 81 / 0 0 0 0 BAYVIEW/PORT ISABEL 90 77 90 78 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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