textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 624 PM CDT Fri Apr 3 2026

Key Messages:

* Significant weather pattern change (cooler and wetter) is expected to take place this weekend through early next week.

* Much needed rainfall in the form showers and thunderstorms are expected to bring some drought relief to the region this weekend through early next week.

* Heavy rainfall and slow moving thunderstorms could result in instances of flooding/flash flooding over parts of the area.

* WPC has all of Deep South Texas and the Rio Grande valley under a Marginal Risk (Level 1 of 4) of Excessive Rainfall on Saturday and Sunday.

* Preliminary rainfall amounts by Monday morning will range between 1-2 inches with locally higher amounts; additional rainfall amounts are possible Monday-Tuesday.

* Outside of the risk for showers and thunderstorms Saturday night through early next week, adverse to hazardous marine conditions are expected through next week.

DISCUSSION

Issued at 246 PM CDT Fri Apr 3 2026

A significant weather pattern change (cooler and wetter) is in the offing this weekend into the early parts of next week. After 6 months of long-term drought (since last October) that has much of the region currently under a D3 (Extreme Drought) to D4 (Exceptional Drought), much-needed rainfall is on the way across Deep South Texas and the Rio Grande Valley. A cool frontal boundary ejecting out of the southern Rockies and sweeping through Texas will be the focus of waves of scattered to numerous showers and thunderstorms this weekend into the early parts of next week. Showers and thunderstorms will develop over Deep South Texas ahead, along, and behind this frontal boundary.

During the day on Saturday, ahead of the cool front, strong warm air advection (WAA) on breezy southerly winds, will allow for high temperatures to rise into the upper 80s to lower 90s near the coast to the mid 90s further inland (all above normal levels). Additionally, southerly winds 10-20 mph with gusts up to 30 mph will allow for deep/rich tropical moisture to continue to advect into the region. Dewpoint (Td) values are expected to rise into the lower 70s across the region with precipitable water (PWAT) values rising to between 1.75-2 inches, some +1 to +3 STDEVs above normal.

During the day on Saturday, most of any showers and thunderstorms that form will be confined to the western sections of the area (i.e. along and west of IH-69C). That's where we currently have PoPs ranging between 30-60%. Saturday evening and especially Saturday night, the coverage and probabilities for showers and thunderstorms will spread eastward to include the rest of Deep South Texas and Rio Grande Valley. Categorical PoPs will begin Saturday night (ahead of the front) and prevail through Sunday night (behind the front) as the aforementioned cool front pushes through the region. Overall, appreciable rainfall amounts are expected from this event. Preliminary rainfall estimates by Monday morning is still in the 1-2 inch range with locally higher amounts.

While, a strong to severe thunderstorm or two is possible during this event, the main concern will be on the hydrology side. Given the high atmospheric moisture content (i.e. PWAT values between 1.75-2 inches, some 2-3 STDEVs above normal) and the fact that these storms will likely be slow movers due to the lack of air flow aloft (i.e. LCL-EL winds being weak), heavy rainfall could result in instances of flooding/flash flooding across parts of the area. (flooding/flash flooding is possible in this supersaturated environment).

The Weather Prediction Center (WPC) has maintained the entire area under a Marginal Risk for excessive rainfall for both Saturday and Sunday. Oil slick roads are possible at the onset of any rainfall. That said, we urge motorist to review flood safety tips at weather.gov/safety/flood. Additionally, motorists should save extra time to get to their destinations if you must go out, leave extra distance space between vehicles, drive slowly, and never attempt to drive over flooded roadways.

Some lingering post-frontal showers are possible Monday and Tuesday. On Monday, PoPs will begin to decrease with values ranging medium- high between 40-70% (highest southeast). Categorical PoPs on Monday will be confined across Mid-Lower Valley. The drying out process could begin as early as Tuesday. On Tuesday, PoPs are ranging low- medium between 20-40% (highest mid to lower valley). Overall, grand total rainfall amounts from Saturday through Tuesday will range between 1-3 inches with locally higher amounts. These amounts will certainly help to address the D3 (Extreme Drought) to D4 (Exceptional Drought) over the region. If not Tuesday, Wednesday, will begin the drying out process across Deep South Texas as high pressure builds into the region. Dry and tranquil weather conditions will persist through the remainder of the week.

Temperatures will be that of a roller coaster pattern. We start off up or above normal on Saturday with highs mainly in the 90s across the region. As mentioned earlier, the cool frontal passage along with the presence of showers, thunderstorms, and clouds will result in cooler than normal temperatures across Deep South Texas and the Rio Grande Valley Sunday through Tuesday/Wednesday of next week. Warmer than normal temperatures return to the region next Thursday and Friday. Daytime highs Sunday through Tuesday are progged to be in the 60s/70s. By Wednesday, daytime highs are expected to be in the low to mid 80s and by Thursday/Friday the mid to upper 80s. Outside of tonight, overnight lows will mainly be in the 50s/60s.

AVIATION

(00Z TAFS) Issued at 624 PM CDT Fri Apr 3 2026

VFR to MVFR conditions are expected with gusty southeasterly winds persisting into late tonight. A southeasterly breeze is anticipated on Saturday, but not as gusty as today. The chance of showers and isolated strong to severe thunderstorms increases just beyond this TAF period from the northwest into Saturday night.

MARINE

Issued at 246 PM CDT Fri Apr 3 2026

Outside of the threat for showers and thunderstorms Saturday night through early next week, adverse to hazardous marine conditions can be expected through the forecast period or through next week. Mainly Small Craft Exercise Caution (SCEC) conditions can be expected. There could an instance of Small Craft Advisory conditions on Sunday.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 73 88 71 78 / 20 10 80 90 HARLINGEN 69 90 66 78 / 20 10 90 90 MCALLEN 75 94 69 77 / 20 20 90 90 RIO GRANDE CITY 73 93 63 71 / 20 40 90 90 SOUTH PADRE ISLAND 74 80 72 75 / 20 10 80 90 BAYVIEW/PORT ISABEL 71 87 69 78 / 20 10 80 90

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Advisory until midnight CDT tonight for GMZ130-132- 135-150-155-170-175.