Areas of rain, mountain snow and colder air will dip into Southern California later this week.
According to AccuWeather Senior Meteorologist Ken Clark, "A change in the weather pattern will bring the storm track farther to the south with rain and mountain snow for much of the state during Thursday and Friday."
Storms have been blasting the northwestern United States since November.
Rain to Create Roadway Hazards
From late Thursday through Friday, motorists should be prepared for slick roads due to rain showers in low elevations, including the cities of Los Angeles, San Diego, Bakersfield, San Bernardino and Riverside, California.
The combination of moisture and oil residue on the roads can make intersections especially slippery, where extra stopping distance will be needed. People will also need to reduce their speed on the highways during the showers due to the risk of hydroplaning.
The rain will stop well short of the intensity needed for causing widespread mudslides. However, it is possible there may be enough rain on parts of the San Gabriel Mountains to cause minor sporadic debris flows, especially in recent wildfire burn areas.
Rain may fail to reach many desert locations.
Storm to Unload Heavy Snow on Sierra Nevada
"The storm will put down 1-2 feet of snow in the Sierra Nevada, including ski resorts with the greatest amounts in the northern areas," Clark said.
Significant snow will push across the Intermountain West during the latter part of this week and this weekend.
Snowfall in the Sierra Nevada during the cold weather season is critical for warm season water consumption in California. As the snow melts during the spring, the runoff seeps into the ground and flows into area streams and rivers.
Another potential problem for commuters with the storm will be lowering snow levels, which could dip down to Tehon and Cajon passes by Friday. The storm will not bring heavy snow to these areas but perhaps just enough to coat roads near the summit.
A frost or freeze may follow in the normally colder locations following the storm by this weekend.
Rain, Snow to Have Minimal Impact on Drought
While the moisture will snap the latest short-term rain-free streak and will bring another dose of much-needed snowfall to the Sierra Nevada, it will not even come close to alleviating the long-term drought.
According to AccuWeather Chief Long Range Meteorologist Paul Pastelok, the long-term precipitation outlook for this winter in California is looking better than it has in years.
"The cumulative effect of the snow from this storm, earlier events this fall and what is anticipated through the winter should go at least part way toward raising stream levels and refilling lakes and reservoirs," Pastelok said.
Through this winter, the precipitation during should be enough to be beneficial for summer of 2016.
However, the rainfall deficit in parts of Southern California has topped 20 inches over the past several years and will take more than a few major storms and one winter to break the drought.
"In many cases it may take a few above-average rain seasons in a row to erase the drought," Pastelok said. "We remain highly skeptical that this will be the start of a multiple-year, above-average rainfall pattern."
Pastelok stated that there is often a pattern with very little rainfall following an El Niño during the next rainy season. Such a rebound in the dryness could put California right back into intensifying drought.
Whether or not the main storm track will set up in the southern part versus the northern part of the state, some moisture will extend well to the south on occasion this winter.
Rain and heavy mountain snow are forecast to reach the northern areas of the state and at least part of central California and the Sierra Nevada through the winter.
Rainfall could visit Southern California with greater frequency as early as the latter part of December.