The National Weather Service (NWS) in San Juan extended a flood warning Thursday until 5:30 p.m. for the municipalities of Ceiba, Fajardo and Naguabo, as well as parts of southern Luquillo and Río Grande, due to heavy rainfall. The Río Blanco overflowed its banks and began flooding low-lying areas. A sensor installed on the river confirmed the water level was out of its channel, meaning PR-191 could become impassable.
The NWS also warned of possible flooding on PR-31, particularly at exit 22 toward the PR-53 highway, with access to the expressway potentially affected by water accumulation. As of 2:56 p.m., Doppler radar showed heavy rain associated with thunderstorms; between 1 and 3 inches of rain had already accumulated in parts of the area, with an additional 1 to 2 inches expected.
The agency warned conditions could cause rapid rises in streams and channels that are normally dry, as well as dangerous currents at low-level crossings and water buildup on roads. The NWS urged drivers not to attempt crossing flooded roads and recommended reporting any flooding to emergency services or authorities when it is safe to do so.