Tropical remnants and an upper level disturbance will bring heavy rain and gusty winds to the Desert Southwest, with impacts expected to stretch well inland from the coast, according to weather.com meteorologist Caitlin Kaiser. The system will also interact with a colder front to produce mountain snow in parts of the northern Rockies.
Widespread rain totals of one to five inches are expected across Southern California, Nevada, Utah and Arizona, with locally higher amounts possible and a heightened risk of flash flooding in normally dry creeks, arroyos and urban areas. Cities mentioned at risk include the L.A. Basin, San Diego metro, Las Vegas and Salt Lake City, and officials were advised to consider canceling national park trips until Wednesday because of flood and thunderstorm dangers.
Strong gusts are likely through higher terrain in Arizona, Nevada and Utah, raising the prospect of tree damage, blowing dust and power outages as the storms move inland, Caitlin Kaiser said. As the tropical moisture meets colder air, parts of the Sierra Nevada and the Rocky Mountains could receive measurable snow, with locations in Wyoming, Montana and Idaho possibly seeing more than a foot.
The approaching flow will also bring a cooling trend across the region. Temperatures are forecast to fall five to 15 degrees below average, with Southern California highs dropping into the upper 60s and 70s, and portions of Arizona and New Mexico falling into the 70s and 80s.
Meanwhile a powerful Hurricane Simon is tracking along Mexico’s southwest coast at Category 4 intensity, the National Hurricane Center said. A hurricane warning is in effect from Punta San Telmo to El Roblito and includes Las Islas Marias, with the agency warning of catastrophic winds and life threatening storm surge along parts of the west central coast.
The NHC also cautioned that Simon could produce as much as 30 inches of rain in some areas, creating a dangerous landslide risk in hilly terrain. The agency said Simon may be the strongest hurricane to affect Puerto Vallarta since Hurricane Lidia in October 2023. Some of Simon’s moisture may later feed into the central US, enhancing locally heavy rain and thunderstorms into midweek.
Dry Weather Aids Isaias Recovery Across The South
In the Southeast, a break from rain is providing welcome conditions for cleanup after Hurricane Isaias struck near Destin, Florida, as a 105 mile per hour Category 2 storm, AccuWeather reported. Dry weather should help crews clear debris and work to restore utilities across the hardest hit communities.
Pensacola Beach and other areas along the central Gulf Coast took major wind and flood damage, with a 116 mile per hour gust reported near Santa Rosa Sound and widespread infrastructure impacts. More than 350,000 utility customers in Florida and Alabama remained without power as crews continued restoration efforts, AccuWeather said.
Heavy rain fell inland as Isaias moved, with Bellwood, Alabama reporting 12.97 inches and some floodwaters expected to linger for several days. For some rivers along the Florida Panhandle, projections showed water levels at or above minor flood stage into Tuesday afternoon, which could prolong road closures and delay recovery in low lying areas.
AccuWeather meteorologist Dan Pydynowski noted a warming trend into midweek, with highs reaching the upper 80s to lower 90s across parts of the Southeast. The heat may add stress for residents without air conditioning as crews work on repairs. Forecasters also flagged continued heavy rain risk across portions of the Northeast into Monday morning before milder, drier conditions arrive.
