Yet another storm is on the docket that we’re tracking this week into next week. Currently, it’s this robust-looking storm swirling off the Northwest coast, as shown on satellite imagery below. It is the piece of energy that will separate from this system, moving into California and tracking from the Southwest U.S. through the Midwest, and bring widespread snow to the intermountain West and portions of the Plains and Upper Midwest. It will also bring rain and thunderstorm for most of the Eastern U.S. from this weekend through early next week.

We will begin to feel impacts of this storm Wednesday afternoon. Specifically, it will be along the coast of Washington and Oregon where light rain showers will begin to creep in, while a light mountain snow breaks out across the northern Cascades of Washington. The storm won’t really start to get its act together until Wednesday night. That’s when the precipitation will increase in intensity. Rain will move further inland, affecting most of Washington, the western half of Oregon, and even Northwest California north of the Bay Area and the northern tip of Idaho. Elevation snow is the forecast for all of the Cascades. Snow levels will mainly be above 5,000 feet, so we don’t think there will be too many issues through the passes with this storm, until potentially Thursday night.




On Thursday, the precipitation shield will continue to increase. Rain showers are forecast for much of Washington, all of Oregon, Northern California, and some of the lower elevations of northern Idaho. Meanwhile as you go up in elevation, it will be snowing in the Cascades, the Oregon Plateau, Blue Mountains, the Sawtooth Mountains, the Bitterroots, the Klamath Mountains of California, and the other mountains, like Mount Shasta in California. These mountains in Northern California will likely experience the heaviest snowfall rates of up to two inches per hour.

Thursday night, the precipitation will continue to expand south and east as our main storm system approaches the California coast. Rain showers are forecast for the Pacific Northwest coast, portions of Northern and central California. Also the low elevations of Idaho and eastern Washington will be included in the rain showers. Mountain snow will continue in the Cascades down to the northern Sierra, coastal range of California and southwestern Oregon, and the same areas in eastern Oregon, Idaho, and western Montana. Also portions of northern Nevada will get in so some snow showers.




The constant stream of moisture will continue on Friday for the Northwest, leading to showers along the coast from Washington through Northern California. A few showers are also possible in the Central Valley of California and southern Idaho. Snow will persist across the same areas that dealt with it on Thursday through the night. The only exception is that snow will now also include the remainder of the Sierra. The Sierra Mountains will finally receive much-needed snow. Up to two feet is forecast for the highest peaks through Friday night, which is when the snow will begin to come to an end.

Friday night, rain showers will continue along the coasts of Washington and Oregon with snow still falling in the Cascades. Most of California will dry out with light rainfall totals forecast for the most part. Only up to half an inch at most of rain is forecast for the Golden State. Now in Southern California, most areas will thankfully be dry because we don’t need any more mudslides. We will see rain showers changeover to snow in the San Gabriel Mountains, where up to half a foot of snow will fall. For the rest of the West, there will be a swath of light to moderate snow stretching from northern Wyoming through northern Utah, and into central Nevada. Salt Lake City will be only of this cities forecast to receive a few inches of snow during the Friday night time period.

EURO 500mb Vorticity

On Saturday, the storm system will move onshore, leading to snow showers because of cold air aloft to the northern mountains of Arizona, which has been scarce so far this winter. Light snow will also sneak into the Rockies of western Colorado as the day progresses. Meanwhile, snow will continue across much of Wyoming, Utah, central Nevada. In the northwest, the rain and snow will finally settle down by the evening, but not before a new storm plows into the Northwest on Sunday.




Now that we’re looking farther out in time, the forecast uncertainty and the details become a bit more uncertain. A surface low pressure will form on the leeward side of the Rockies in Colorado on Sunday. This is what we call a “Colorado Low.” With this storm, a light to moderate to perhaps heavy swath of snow will stretch from the Central Plains through the Upper Midwest from Sunday through Monday night our Tuesday. Meanwhile across the Eastern U.S., a line of rain showers and thunderstorms will develop ahead of a cold front associated with the surface low by the end of the day Sunday. This line will start from around eastern Texas and Oklahoma, and will move to the east, affecting most areas in the Eastern U.S. through Tuesday night. On the backside of the low, light snow showers may develop due to the intrusion of freezing temperatures in the Great Lakes region and interior Northeast. Stay tuned to WeatherOptics for details on the second phase of this storm.

With all of that in mind, here’s a general overview of the storm setup and where the different precipitation types may fall:

Author

Jackson is COO and Head of Content and Strategy of WeatherOptics. He also designed his own website and created the local company, Jackson's Weather. He has been forecasting the weather for southwestern Connecticut since March of 2015. He is currently a senior in high school and will major in Meteorology and Broadcast Journalism at the University of Miami in Fall 2018.

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