National Weather Service United States Department of Commerce

Marine and Coastal Impacts from Imelda; Unsettled Weather in the West

Swells and high surf from both Imelda and Humberto are expected to bring dangerous marine conditions and rip currents to much of the East Coast over the next several days. A series of Pacific frontal systems will bring waves of showers and thunderstorms to portions of northern California and the Pacific Northwest through midweek. 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.