National Weather Service United States Department of Commerce

Winter Returns Across the Northern Tier; Record Warmth for the Southwest

A large high pressure system will usher in cold air for this first day of March across the northern Plains, Great Lakes, Northeast and mid-Atlantic. Some wintry precipitation may evolve across the mid-Mississippi Valley, Ohio Valley and mid-Atlantic through Monday. Meanwhile, record warmth will spread across the Southwest, southern Plains through early this week. 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.