National Weather Service United States Department of Commerce

Dangerous Cold Persists through Monday; Wintry Weather from the Northern Plains to the Great Lakes

Bitter cold temperatures and dangerous wind chills will persist from Florida to the Northeast through the day. Daily record low temperatures are forecast across the Southeast and Florida, with some all-time February low temperature records possible across Florida. An Alberta clipper will spread wintry precipitation across the Northern Plains today and into the upper Great Lakes into tonight. 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.