A weather system moving across the Caribbean is expected to bring significant rainfall to St. Thomas and St. John starting late Sunday, with the highest flood risk concentrated on Monday and Tuesday, according to the National Weather Service.
The atmospheric pattern—a mid to upper level trough—will move southeastward from Hispaniola and reach the U.S. Virgin Islands late Sunday into early Monday. As it progresses, the system is expected to intensify, creating conditions favorable for periods of heavy rain, particularly across the northern and eastern portions of the territory.
What to expect this weekend and early week
The first wave of showers is forecast to arrive Sunday night, with more widespread activity developing Monday morning. Initial rainfall may be moderate, but conditions are expected to deteriorate significantly by Monday afternoon and into Tuesday as the system’s core passes overhead.
Weather service forecasters are predicting daily rainfall totals between one and three inches, with isolated areas potentially receiving higher amounts. St. Thomas and St. John are identified as zones of particular concern, along with Vieques, Culebra, and eastern Puerto Rico.
Rising flood potential
The combination of recent rainfall and ongoing soil saturation across the eastern and southern portions of Puerto Rico has elevated flood risk across the broader region. Streams throughout the territory are currently running near or above normal levels, leaving little buffer capacity for additional water.
Hydrologic officials have raised the likelihood of urban and small stream flooding, isolated flash flooding, landslides, and rapid river rises as the system approaches. While a brief dry period earlier this week allowed some soil drainage, widespread saturation remains a limiting factor.
The National Weather Service cautioned that confidence in the forecast remains at medium levels, though consistency between weather models is increasing. Exact rainfall amounts, timing, and the precise locations most severely affected remain uncertain, and cloud cover patterns could suppress rainfall totals in some areas.
Preparation and outlook
Residents of St. Thomas and St. John should review their personal preparedness plans and ensure drainage systems around homes and businesses are clear. The territory’s Department of Planning and Natural Resources maintains flood plain information and maps to help residents understand their area’s vulnerability to inundation.
Above-normal atmospheric moisture is expected to persist through late in the week, suggesting that even after the primary system passes, elevated rainfall risk may continue. The National Weather Service indicated it will update its hydrologic outlook as new forecast data becomes available.
Residents are advised to monitor official weather updates and heed any warnings or advisories issued as the system approaches.
