Two storms will roll ashore from the Pacific this week, with one aiming for Southern California followed by a second larger storm that will blast much of the West Coast with drenching rain and heavy mountain snow. While the storms will create travel problems and some dangers, AccuWeather meteorologists say they will also offer some drought relief.

The first storm will push in across Southern California on Tuesday before pressing quickly eastward across the interior Southwest and then the South Central states by midweek.

The Tuesday storm will bring up to an inch of rain to coastal areas of Southern California, with the greatest amounts and locally higher totals along the west- and south-facing slopes of the Coast Ranges.

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San Diego should receive a thorough soaking and could hit its biggest single-storm rain event of the wet season that began on Oct. 1. The same storm will produce severe thunderstorms in the South Central states at midweek.

A much more potent and far-reaching storm will drop southward along the Pacific coast from Wednesday to Thursday.

This storm will bring soaking low-elevation rain and significant snow to the passes and higher elevations of the Washington and Oregon Cascades at midweek. In these areas, the precipitation will linger through the end of the week. However, as the air turns colder, snow levels will dip to nearly 1,000 feet by Friday, which may allow some snowflakes to be seen on the hills around Seattle and Portland, Oregon.

Wednesday and Thursday, the main thrust of the storm’s moisture is forecast to be directed at California when the corridor of heavy rain and mountain snow will slide slowly southward. Much of the precipitation will occur in a 12-hour period.

The rain can be intense enough to lead to urban flooding, road washouts, debris flows and other slides at low elevations, especially in coastal areas from San Francisco to Los Angeles and San Diego. The snow can fall several inches per hour, easily overwhelming road crews and leaving motorists stranded.

As the storm drops southward along the coast, the major airport hubs from Seattle to San Diego may experience ground stops and flight cancellations.

In the Sierra Nevada, a general 2-4 feet of snow is forecast to fall over the higher elevations, with an AccuWeather Local StormMax™ snowfall of 7 feet over some of the ridges and peaks. Soon after the snow piles up, the risk of avalanches will increase on the steep slopes.

Motorists should expect lengthy delays due to slippery conditions with the potential for road closures. Portions of Interstates 5 and 80 over the higher terrain may close for a time during the storm spanning Wednesday to Thursday.

Snow levels will dip to near pass level over the Grapevine in Southern California, with up to a few inches possible from Wednesday night to Thursday night. The ridges and peaks of the mountains in Southern California can pick up a foot of snow or a bit more.

From Thursday to Friday, the storm will cross the Intermountain West with areas of low-elevation rain and mountain snow before triggering an outbreak of severe weather over the Central states from Friday to Saturday and blizzard conditions for parts of the northern Plains.

More storms are lining up over the Pacific with eyes on the West Coast. At least one significant storm is due in for the Northwest and California later this weekend. Additional storms are likely for at least part of the Northwest next week.

The storms through the middle of the month will continue to bolster lakes, reservoirs and rivers in the Northwest to Northern California.

The storms into this weekend will also continue to chip away at the short-term drought conditions that developed in Southern California since the start of the rainy season.

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