United States

By Anthony Sagliani, Meteorologist

October 12, 2012; 5:58 AM

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The record dry stretch may be in jeopardy with a big weather pattern change later this week.

Though a blocking shield of high pressure still remains steadfast over the Northwest, a powerful ocean storm currently over the middle of the Pacific will cause it to crumble by early next week.

The first blow will come on Friday into Saturday as light to moderate rain along a cold front slams ashore.

Places from Bellingham south to Seattle and Portland will have a good 1-2 inches of rain from this storm, with more in the foothills of the Cascades.

The second storm will hit on Sunday night through Monday and deliver the knockout punch to whatever might remain of the blocking shield of high pressure.

This storm will pack powerful winds of 40-60 mph along the coast with torrential rain elsewhere. Heavy snow will even fall in the highest elevations, mainly above pass level.

This storm will bring 2-4 inches of rain from Eugene to Quillayute, with a few localized areas receiving up to 6 inches or more.

With this much rain falling in only a few days span, runoff is likely to cause flooding along area creeks, streams and smaller rivers.

Those traveling later this week into the first part of next week will also have to contend with flight delays in and out of Seattle and Portland, so it might be a good idea to plan ahead now.

Along Interstate 5 from Medford north to Salam and Bellevue, and 90 from the Cascades east to the Puget Sound, motorists will need to deal with ponding on roadways, urban flooding and periods of blinding rain and slow-going travel.

An added issue will be any leaves that might come down from the autumn foliage. Leaves on the road when wet can become as slick as ice.

The heavy rain and parade of storms is not all bad, however. This is the time of year when the wet season really begins to ramp up along the Northwest Coast.

The wetting rain will douse old flames from wildfires and wet the lips of thirsty inland creeks and streams.

Many residents in places such as North Bend, Ore., where it hasn't rained since July 21st, will no doubt enjoy getting back to the wet weather and saying goodbye to what has been a very warm and dry end to summer and early fall.

Keep checking back with Accuweather.com for the latest on this upcoming storm, and for all the rest of your weather needs.