The National Weather Service today is warning that a week of warm and sunny weather could trigger rapid rises on rivers and streams in the Inland Northwest. Temperatures are expected to reach the lower 80s in Spokane today and stay in the lower 80s or upper 70s through the rest of the week under abundant sunshine. Streams fed from the mountains of British Columbia and the Cascades are going to rise as a result. The Okanogan, Similkameen, Wenatchee, Methow, Kettle, Moyie, Kootenai and Entiat rivers are among the streams that will see a fast runoff this week. A flood warning was issued for the Naches River west of Yakima and a flood watch is in effect for the Okanogan River northwest of Spokane. A lack of rain in recent weeks is allowing snow to run off without creating more severe flooding potential. A strong area of higher air pressure has moved over the Pacific Northwest, bringing an extended period of summer-like weather.