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Arctic Air Mass Lingers for Areas of the East; Critical Fire Weather for the Plains; Active Weather Pattern for Hawaii

Arctic air lingers for the east, however, winds will slowly subside and a slow moderating trend starts during the week. Moisture continues to provide rainfall and higher elevation snow for the Pacific Northwest, northern California and northern Rockies through Monday. For the State of Hawaii, dangerous surf conditions with strong winds and heavy rainfall will impact the islands through Monday. 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.