A storm will bring a wide range of weather to the West into this weekend as it drops across California and turns eastward toward the Rockies and High Plains.
In addition to spreading cooler air through much of the Southwest, the storm system will bring everything from gusty thunderstorms with spotty hail and locally drenching downpours to blowing dust, a couple of tornadoes and high country snow.
The storm will bring hazards for those traveling on the highways, ranging from poor visibility to wet roads and slushy snow in the passes well inland.
Cold air aloft associated with the storm will first create spotty downpours on Thursday and Friday from California to much of Nevada, Utah and northern Arizona.
Rain of any amount is generally welcomed in California at this stage. However, the nature of the pattern will not deliver enough rain to significantly impact the extreme drought.
Some of the downpours could strengthen into locally gusty thunderstorms with hail.
A small number of the strongest storms could produce a tornado or waterspout in California.
According to AccuWeather.com Senior Meteorologist Ken Clark, "Even though hail is likely to be small in diameter and any tornado very brief, people should keep an eye out for rapidly changing weather conditions if they will be outdoors away from shelter."
People should use caution on city streets and highways including around Los Angeles, San Diego and Sacramento, California, where the mix of oil and rain can make stopping and cornering difficult.
"While the damp pattern forecast to be produced by this storm will not create widespread dry lightning strikes, a small number of storms could bring so little rain as to spark a wildfire," Clark said.
Gusty winds and sparse or non-existent rainfall across the desert areas could kick up blowing dust. Areas around Las Vegas and Phoenix could be affected.
Sudden low visibility from blowing dust has resulted in chain-reaction accidents in the past on highways such as Interstate 10, I-15, I-17 and I-40.
As the storm swings farther east, a significant outbreak of severe weather, including the risk of powerful tornadoes is likely over portions of the Plains this weekend.
The storm will not produce enough cold air to bring snow to Cajon or Tejon passes in California, but snow will fall on Donner Pass along I-80, in the Wasatch and Rocky Mountains.
"Snow levels will dip to around 6,000 feet at night over the Sierra Nevada with several inches of snow likely in the high country," Clark said.
Road conditions at Donner Pass will range from wet to slushy.
The right atmospheric conditions will set up to bring accumulating snow to the higher elevations of Colorado and Wyoming later in the weekend. Portions of I-70 in Colorado and I-80 in Wyoming could be slushy and slippery with poor visibility.
While heavy snow is not forecast for Denver, a foot of snow could fall on the high country of Colorado and Wyoming. Several inches of snow may fall on the foothills west of Denver and in Cheyenne, Wyoming.
Utilize AccuWeather MinuteCast® for your location to get an exact start time on the rain, snow and storms that may impact your plans.