The National Weather Service (SNM) in San Juan reported that weather conditions in Puerto Rico will become more unstable in the coming days, with an increase in rain and thunderstorm activity that could cause urban and small stream flooding, especially between Saturday and Sunday. A disturbance in the trade winds is moving over the region, bringing humidity to the island. Rainfall was already registered in the north, east, and southeast of Puerto Rico, as well as in the islands of St.
Thomas and St. John, with some areas accumulating between a quarter and over half an inch of rain since midnight. The agency explained that most of the Saharan dust has moved west over the Mona Passage, so concentrations will decrease in the coming days, but are expected to increase again from Sunday night.
For Friday, the combination of available humidity and low pressure in the upper levels of the atmosphere will favor scattered showers over exposed areas during the morning, and thunderstorms in the interior and west of Puerto Rico in the afternoon, where there is a risk of flooding. The SNM also warned of the possibility of rain in the San Juan metropolitan area due to the 'El Yunque streamer' pattern, which can transport showers from the Luquillo Mountains to the north of the island when east-southeast winds prevail. Conditions could improve slightly between Friday night and Saturday morning, but will change again with the arrival of a weak tropical wave, increasing humidity and the risk of flooding in the east, interior, west, and northwest of Puerto Rico.