Monsoon flooding devastates Twentynine Palms — and reveals its heart
… The July 14 storm developed extremely quickly, said Ashley Nickerson, a meteorologist with the National Weather Service in Las Vegas. In just two to three hours, roughly 1.88 inches of rain fell on Twentynine Palms, which normally gets 3.87 inches in a year, she said. Monsoon storms typically form when an area of high pressure draws moisture up from the Baja Peninsula and other parts of Mexico and then the wind turns to blow from the south, pushing that moisture into California, southern Nevada and Arizona, she said. Forecasters will generally see monsoon conditions developing a couple of days in advance, but they often can’t pinpoint where the storms will form, she said.