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Snow Squalls May Impact New Year's Eve Travel from the Great Lakes to the Northeast; Heavy Rain Returns to California

An Alberta clipper will bring lake effect snow downwind of the Great Lakes, with the highest snow totals downwind of Lakes Erie and Ontario. Snow squalls may impact New Year's Eve travel during the evening and overnight hours across parts of the Great Lakes, Ohio Valley, and Northeast. Heavy rain will bring a flash flooding threat for southern California on New Year's Eve into New Year's Day. Read More >

Mountain Wave Activity Over the Southern Rockies

When stable air flows over the rugged terrain in and around New Mexico, mesoscale circulations known as mountain waves can develop. An example is shown in the visible satellite image below. When the wind speed is sufficiently strong and perpendicular, or nearly-perpendicular to mountain ranges, waves develop over and downstream of the barriers. If enough moisture is present in the air, clouds will develop in the portion of the wave with upward vertical motions. While the wind speeds may be 30 kts or greater, the waves remain nearly stationary for periods up to several hours. While these waves are visually appealing, both in satellite imagery and from the ground as lenticular clouds, these waves are often associated with turbulence and therefore, are considered to be an aviation hazard.

A study on criteria associated with mountain waves over New Mexico was completed in 2004, and is available in pdf format.

animation of satellite imagery depicting mountain waves
 

Visible imagery from 18 October 2004 illustrating an extensive area of mountain waves over the Four Corners region.