(CNS) – Monday morning’s crisp weather isn’t expected to last, with rainfall set to start as soon as Monday evening in Riverside County, according to Southland forecasters.

Part of a new wave of storms expected this week, the National Weather Service predicts rain could begin falling in Riverside County Monday night and continue into Tuesday morning. Heavier rain and strong winds are forecast as part of a stronger Pacific storm system expected to impact the Southland Wednesday through Thursday.

Clouds were thickening Monday with partly and mostly cloudy skies expected to blanket the Southland Tuesday, growing denser as the frontal system over the eastern Pacific approaches the area. In general, most areas will see a half inch to an inch of rain Monday and Tuesday, according to the NWS. Snow is likely for the higher elevations.

A pop-up ridge will provide a brief reprieve from the rain as it moves over the area Tuesday afternoon for dry weather overall and decreasing cloud coverage, forecasters said.

However, SoCal remains on track for a powerful storm system to affect the area starting Wednesday and continuing through Friday, forecasters said. Up to six inches of rain are expected in some areas, with snow at higher elevations. The heaviest rainfall is expected to occur late Wednesday through Thursday morning.

Wind advisories and warnings are likely Wednesday into Thursday, according to the NWS.

Already, weather conditions have prompted a high surf advisory in Orange County and San Diego County through 6 p.m. Monday. Various wind advisories also are in place from 4 to 6 p.m. Monday in mountain, valley and desert regions of San Diego, San Bernardino and Riverside counties.

Health officials are warning people to avoid entering ocean water near discharging storm drains or rivers due to possible bacterial infection. The Los Angeles County Department of Public Health issued an ocean water quality rain advisory that will be in effect until at least 7 a.m. Tuesday.

Health officials noted that stormwater runoff that reaches the ocean can carry bacteria, chemicals, debris trash and other health hazards. People who come in contact with impacted water in the ocean could become ill, health officials said.

Temperatures are expected to be cool throughout the week, with highs in the 50s and 60s in most areas.

Forecasters Predict More Rain This Week