Puerto Rico will see another hot day on Wednesday, with a heat advisory in effect from 10:00 AM to 4:00 PM, during which heat indices could range from 100 to 108 degrees Fahrenheit, especially in urban and coastal areas, according to the National Weather Service (NWS) in San Juan. Light concentrations of Saharan dust could cause hazy skies.
Rising humidity and daytime heating will favor showers and thunderstorms in the afternoon, starting over the Cordillera Central and spreading to other sectors, since winds will remain relatively weak. Some thunderstorms could bring heavy rain, frequent lightning and wind gusts, and slow-moving showers raise the potential for urban flooding and flooding of small streams. Precipitable water will rise to between 2.0 and 2.2 inches during the day.
The NWS expects an even rainier pattern on Thursday, when the GFS and ECMWF models project precipitable water near 2.3 inches, with south to southwest winds transporting moisture into the region. Heavier, more widespread rain is expected in the afternoon, particularly in the interior, north and east of Puerto Rico, and the unsettled pattern could extend into Friday.
Thursday profiles as the day with the greatest potential for widespread, intense rain. The NWS warned of increased risk of urban flooding, flash flooding of streams and landslides in steep areas, and urged residents, especially those in flood- or landslide-prone zones, to stay alert to forecast updates and any advisories or warnings issued.