Flash Flood — San Lorenzo, Puerto Rico

2010-07-19 · near San Lorenzo, San Lorenzo, Puerto Rico

Event narrative

A house was reported flooded at Urb. Vistas de San Lorenzo, Lirio road in the municipality of San Lorenzo.

Wider weather episode

An active tropical wave moved across Puerto Rico and the U.S. Virgin Islands on Monday July 19, generating numerous showers and isolated thunderstorms, some with very heavy rain. Weather conditions improved during the evening of Monday July 19, but by early morning July 20th, additional showers and thunderstorms resulted in flooding across much of the eastern half of Puerto Rico. Although by Tuesday morning July 20 the tropical wave axis had moved into Hispaniola, the wave itself was maintaining a broad area of disturbed weather, aided in part by an upper level low pressure system just north northwest of the local area. As a result, Tuesday July 20 was another very active weather day, with heavy rains persisting across the eastern half of Puerto Rico and additional shower and thunderstorm formation across the southwestern sections of Puerto Rico. On Wednesday July 21, local effects combined with available moisture behind the initial tropical wave to generate additional showers and thunderstorms across the eastern and northern sections of Puerto Rico. By this time the soils had become saturated and any additional rainfall greatly increased the chance for flash flooding. By late Thursday July 22, the islands were still dealing with the effects of several days of widespread rainfall. Even though this tropical disturbance, which later became Tropical Storm Bonnie, was now located over eastern Cuba, it was still able to generate another band of moisture which brought additional areas of rainfall across Puerto Rico and the U.S. Virgin Islands. USGS rain sensor at NSSR/Ceiba 3SE recorded 9.03 inches for the 24 hour period ending on July 20th, followed by Rio Grande de Loiza/San Lorenzo which recorded 7.31 inches.

View location on OpenStreetMap → (18.1936, -65.9666)

Source: NOAA Storm Events Database, event_id 248793. Narrative written by the NWS forecast office that issued the report.