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Flooding Risks from Tropical Moisture Across the Southeast and Southwest

Tropical moisture from Isaias and Rachel will impact portions of the Southeast and Southwest this weekend. Flash flooding, strong winds and even a threat for severe thunderstorms and tornadoes are possible. Meanwhile, strong winds and dry fuels are raising fire weather concerns across the central Great Basin and western High Plains. Across the northern Rockies, first winter storm of the season. 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.