The National Weather Service placed all of Deep South Texas under a flood watch on Monday in the Rio Grande Valleywhere tropical moisture is driving heavy rain expected to persist through Wednesday. The advisory covers Harlingen, Brownsville, McAllen and surrounding communities, with the potential for flash flooding in urban and low-lying areas. Last update: June 16, 2026.
The alert matters because widespread totals of 3–6 inches of rain are likely, with localized maxima of 8 inches+ where slow-moving thunderstorms repeat. The risk profile peaked at a Moderate Risk (Level 3 of 4) for excessive rainfall on Monday, shifting to a Slight Risk for the region Tuesday and Marginal to Slight across the eastern half on Wednesday. Residents have been advised to monitor rapid rises on area drains and arroyos and to avoid flooded roadways.
Flash flood risk and midweek forecast
Forecasters indicated numerous flash flooding events were likely Monday, with scattered events possible Tuesday, and isolated to scattered impacts lingering Wednesday. A broad low-pressure area over the east coast of Mexico moved inland but could re-emerge over the northwestern Gulf Tuesday or Wednesday, where conditions may support tropical development by midweek. Formation chances remain low in the near term—0% through 48 hours—and low but nonzero over the next week at 30%. Daily rain chances persist as deep tropical moisture remains entrenched.
Local emergency actions in Cameron and Hidalgo counties
Communities escalated preparations as the rain intensified. The city of Donna distributed nearly 2,000 sandbags on Monday to bolster property protection. In Weslacoa funeral home opened as a temporary shelter for storm-affected residents. Cameron County emergency management deployed 13 pumps across key flood-prone sites to manage standing water and maintain drainage capacity as rainfall bands continued to cycle over the Lower Valley.
Infrastructure, radar outage and school changes
The Texas Department of Transportation staged crews to address flooded roadway segments, clearing debris and monitoring underpasses for rapid closures if needed. The Brownsville Doppler radar is currently down due to a hardware failure, a gap that may complicate short-term storm tracking; forecasters are leveraging alternative data sources to maintain coverage. Several school districts canceled summer school classes and extracurricular activities to reduce travel risk during the ongoing flood watch and anticipated downpours.
Regional declarations and community updates
Weslaco Mayor Adrian Gonzalez signed a local disaster declaration, enabling additional resources for response. All four Rio Grande Valley counties are included in a broader disaster declaration by Texas Gov. Greg Abbottopening access to state assistance. Amid the weather response, McAllen ISD partnered with South Texas College to launch a free two-year veterinary tech apprenticeship. Two Texas State Technical College students won a national emergency medicine skills competition, and a flag retirement ceremony in Weslaco formally retired 22 U.S. flags on Sunday.
