Torrential rains have been affecting the entire country for the past few days. DR1 Weather & Beyond Forum Current Weather thread update for 12 October explains that the rains are the result of an unusually large low pressure system that has remained nearly stationary overnight. The moist surface flow is affecting a large portion of the Caribbean and Central America, from Nicaragua to Puerto Rico, the DR included. The forum thread reports that the good news is that within another 24 hours or so, the island should be clear of it, while still dealing with some flooding and mudslides.
But on the downside, right behind it is a tropical that is moving over the Lesser Antilles and is now along 62 West and just South of 20 North. To follow current weather affecting the DR, see http://dr1.com/forums/showthread.php?t=40978&page=15