textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1247 PM CDT Mon Jun 1 2026

* Rain chances are low (20-30%) tomorrow, and begin to increase on Wednesday, where they should be low to moderate (20-50%) through Friday.

* Chances will be low again Saturday (20-30%) before drying out for next week. * Low to Moderate Heat Risk will be a concern throughout the week, despite seasonal high temperatures.

DISCUSSION

Issued at 1247 PM CDT Mon Jun 1 2026

Weak upper-level high pressure that has been dominant over the region this past weekend is expected to continue weakening tomorrow, giving way to conditions more favorable for rain chances tomorrow. Moisture continues to increase throughout the area as southeasterly flow continues and tropical moisture moves more deeply into the area. This will help support a low (20 to 30%) chance of showers and perhaps a thunderstorm or two along the sea breeze front tomorrow.

Wednesday, rain chances increase throughout Deep South Texas as upper level high pressure further erodes and gives way to weak surface troughing to the west. The atmosphere is expected to remain robustly moist, with PWATS climbing above 2 inches by the weekend, which is anomalous. There is roughly a low to moderate (20 to 50%) chance of scattered precipitation on Wednesday through Friday, with the best chances in the afternoon and early evening. Some of this could fire along the sea breeze during peak afternoon heating, but Sierra Madre convection is possible too as surface troughing in north central Mexico pushes eastward, particularly on Thursday and Friday. Portions of extreme northwestern Zapata County have been included in a Marginal (level 1 of 4) Excessive Rainfall Outlook for Thursday, but the main threat will be to the north-northwest. Chances diminish Saturday (20 to 30%) with mostly sea breeze activity expected, before drying out Sunday into next week.

Heat Risk will be a concern throughout the next week, as humidity levels are expected to remain high which will make the temperatures outside feel warmer than they actually are. Though highs should remain mostly seasonal (upper 80s and lower 90s), "feels like" temperatures will be in the low to mid triple digits. This will support a Low (level 1 of 4) to Moderate (Level 2 of 4) Heat Risk throughout the week, with the highest risk over the weekend into early next week.

AVIATION

(18Z TAFS) Issued at 1247 PM CDT Mon Jun 1 2026

VFR conditions are expected at all airports with a few clouds. Light to moderate southeasterly winds are also expected throughout the TAF period.

MARINE

Issued at 1247 PM CDT Mon Jun 1 2026

Favorable conditions are expected throughout the early weekend. SCEC conditions could develop by Sunday as a pressure gradient tightens ahead of a stalled boundary to the north which will increase wind speeds. Winds should be overall light to moderate, however, and oscillate between being easterly and southeasterly. There is a low (20-30%) chance of offshore showers throughout the week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 79 91 78 90 / 10 30 10 40 HARLINGEN 76 91 74 89 / 10 30 10 40 MCALLEN 78 94 77 92 / 0 20 0 40 RIO GRANDE CITY 77 95 76 93 / 0 10 10 30 SOUTH PADRE ISLAND 81 85 81 85 / 10 20 30 20 BAYVIEW/PORT ISABEL 78 89 78 88 / 10 20 10 30

BRO WATCHES/WARNINGS/ADVISORIES

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