textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 604 AM CDT Mon Apr 20 2026

Key Messages:

* Rain showers with pockets of embedded thunder will continue through Monday evening.

* Heaviest rainfall amounts will be from tonight through Monday morning; additional rain fall amounts by Monday morning will range between 1-2 inches with locally higher amounts near the coast (i.e. areas east of IH-69C).

* Rain chances and coverage begins to dwindle Monday evening into Tuesday with dry conditions returning on Tuesday.

* A High Risk for Rip Currents remain in effect through Monday evening.

* Temperatures warm up through next weekend with highs ranging between the upper 80s (near the coast) to upper 90s (west) Wednesday through next Sunday.

DISCUSSION

Issued at 925 PM CDT Sun Apr 19 2026

The main weather concern for Deep South Texas and the Rio Grande Valley will be the rain chances and trends through the short term period or through Monday night into Tuesday. Latest satellite and radar imagery depicted an overcast deck of stratus to stratocumulus clouds over the region with rain showers/drizzle occurring across 80% of the region. Some embedded thunder was located across the Northern Ranchlands. Sfc analysis indicates the region on the backside or cool sector a cool front with a weak shortwave trough or low pressure system overhead. This weak shortwave/low pressure area will continue to drive rain showers across the region through Monday night as it meanders over the region before weakening by Tuesday.

Categorical chances or medium to high chances (55% to 90%) for showers are in place over all of Deep South Texas and the Rio Grande Valley through Monday. According to the latest CAM guidances and radar trends, the heaviest precipitation should be occurring tonight through Monday morning as a line of moderate to heavy rain showers extending from Brownsville southeast over the Gulf Waters eventually move inland. That said, areas near the coast are favored to receive the bulk of the rainfall tonight through Monday morning. By Monday evening, rainfall or QPF amounts of 1-2 inches is possible with locally higher amounts east of IH-69C. Lesser amounts are expected west of IH-60C. Additional rainfall is possible Monday evening into Tuesday, however, rainfall chances and coverage will drop rather quick as the aforementioned low pressure area weakens and begins to lift/depart to our north.

Tuesday evening/night, we finally begin to dry out. Rain-free conditions are expected to persist through next weekend. This will allow for a warming trend to take place through next weekend. Monday will be cooler than normal due to extensive cloud coverage and rain chances. Highs are expected to hold in the 70s most places. By Tuesday, temperatures will be near normal levels with highs in the low to mid 80s. Wednesday through Sunday, the warmup continues each day. Highs will range between the upper 80s near the coast to the upper 90s west. Overnight lows will be in the 60s and 70s through next weekend.

AVIATION

(12Z TAFS) Issued at 604 AM CDT Mon Apr 20 2026

LIFR and IFR conditions are expected this morning, with little improvement through the afternoon. Showers and isolated thunderstorms are possible, with lower confidence in thunder at this time. Visibility should improve, but will briefly diminish where any showers persist.

MARINE

Issued at 925 PM CDT Sun Apr 19 2026

Mostly adverse (Small Craft Exercise Caution) conditions will be in place through next weekend with wave heights over the Gulf Waters mainly between 4-6 feet. A Small Craft Advisory remains in effect for the Gulf Waters till 1 AM CDT.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 73 69 82 70 / 60 40 40 10 HARLINGEN 72 66 83 67 / 60 40 50 10 MCALLEN 75 69 86 72 / 40 40 40 10 RIO GRANDE CITY 74 66 85 69 / 30 40 30 10 SOUTH PADRE ISLAND 73 72 78 73 / 70 40 50 10 BAYVIEW/PORT ISABEL 73 69 81 69 / 70 50 50 10

BRO WATCHES/WARNINGS/ADVISORIES

TX...High Rip Current Risk through Tuesday morning for TXZ451-454-455.

GM...None.