Remnants of Tropical Storm Rachel are moving across the Desert Southwest, bringing widespread tropical downpours that could lead to flash flooding, according to a report published October 12. While the Southwest faces a significant flood threat through Sunday, Hurricane Simon is currently brushing the coast of Mexico at Category 2 intensity.
The moisture from Rachel is expected to trigger flooding rain and strong winds well inland across the Desert Southwest, including cities such as Las Vegas. Widespread rainfall totals of 1 to 5 inches are anticipated, with some locations potentially seeing even higher amounts. This weather could lead to flash flooding in urban areas and normally dry features like arroyos, slot canyons, and creeks, specifically impacting the San Diego metro, the L.A. Basin, Las Vegas, and Salt Lake City. The showers are expected to linger into Monday, creating a prolonged flood threat for the region.
In Mexico, Hurricane Simon is bringing winds, heavy rain, and storm surge to the region. A hurricane warning is currently in effect for Las Islas Marias. The National Hurricane Center stated that catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico. Additionally, up to 30 inches of rain could lead to dangerous landslides in mountainous or hilly terrain. This storm may be the most damaging hurricane to affect Puerto Vallarta in three years, following Hurricane Lidia in October 2023.
The weather patterns are also affecting the northern Rockies and Sierra Nevada, where moisture from Rachel may meet colder air from a Northwest front to produce snow. In Montana, significant snowfall has already been reported, including 24 inches in Stanford and 19.7 inches in Montana City. Additionally, some of the remnant moisture from Simon could stream into the central United States, potentially boosting heavy rain and thunderstorms Tuesday into Wednesday.
Due to the threat of thunderstorms and flash flooding, officials suggest canceling plans for any national parks in the Southwest until Wednesday.
