By Reginald Stanley. Posted February 17, 2019, 7:53 PM.

A cold disturbance responsible for the region's unstable weather Sunday will allow for sharply colder temperatures overnight Sunday into Monday morning, while the threat of patchy showers also continues into Monday morning.

While precipitation amounts are expected to be light, strong westerly winds will continue overnight. A significant drop in snow levels is expected late Sunday night, down to between 3,000 and 3,500 feet above sea level in western Riverside County. Snow levels could drop further in San Bernardino County, to around 2,500 feet above sea level. Across the Inland Empire in general, snow levels could drop locally under certain conditions. Light snow may accumulate in the High Desert early Monday morning. Heavy snow accumulations are likely above 4,000 feet.

The National Weather Service has issued a Winter Weather Advisory for the Santa Ana Mountains, San Gabriel Mountains and High Desert cities through 3 AM Monday, where snow accumulations of up to at least one inch were possible. The threat of icy roads also exists for these areas into Monday morning. The National Weather Service has also issued a Winter Storm Warning for the San Bernardino Mountains, San Jacinto Mountains, and San Diego County Mountains - which includes the cities of Crestline, Lake Arrowhead, Big Bear City, Big Bear Lake, Running Springs, Wrightwood, Idyllwild-Pine Cove, Campo, Julian, and Pine Valley. The Interstate 15 corridor in the Cajon Pass, as well as Interstate 8 near Campo, will also be affected. Heavy snow above 4,000 feet and strong winds are expected in these areas overnight, contributing to hazardous travel conditions. This Winter Storm Warning will expire at 6 AM Monday morning.

Fairer weather is expected later Monday. Another chance of rain is currently forecast for Thursday.