National Weather Service United States Department of Commerce

Above Average Temperatures in the West; Winter Weather Returns to the Upper Midwest and Great Lakes

Well above average temperatures will continue across the West this week, potentially breaking some daily high temperature records. A storm system dropping south out of Canada will bring a wintry mix to the Upper Midwest and Great Lakes Tuesday, pushing into the Central Appalachians and interior Northeast on Wednesday. Read More >

Wave clouds (or gravity waves): These form when stable air moves over a raised land feature, such as hills or mountains, and is forced upward. Gravity then causes the air to fall back down, and it begins to oscillate, creating that ripple effect. 

 

 

This visible satellite image was taken at 400 pm PDT 9 Sep 2000. The cloud lines oriented north to south are wave clouds. They are the result of west-to-east wind flowing over the Cascade mountains of Washington and the Rocky Mountains of Montana and Alberta.