The National Weather Service (NWS) in San Juan forecast an active, humid Tuesday for Puerto Rico, with conditions favoring showers and thunderstorms. A high-altitude low-pressure system west-northwest of the islands is generating atmospheric instability, combined with increased low-level humidity that keeps precipitable water values above normal for this time of year. During the morning, east-southeast winds will bring showers mainly to the U.S.
Virgin Islands, waters east of the islands, and eastern and southeastern Puerto Rico. In the afternoon, daytime heating, local topography effects and sea-breeze convergence will trigger widespread showers and localized thunderstorms, especially in Puerto Rico's interior and western regions, with potential for strong downpours and thunderclaps. The NWS has issued an elevated risk of excessive rainfall for Tuesday, warning of possible flooding in urban areas, roads, small streams and poorly drained zones, plus a low chance of isolated flash flooding.
This elevated risk will persist through the short-term forecast period, and residents are urged to monitor bulletins and advisories. Wednesday is expected to start drier as a less humid air mass arrives, temporarily limiting morning shower activity, though humidity will later return.