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Heavy Rainfall and Severe Thunderstorm Threats; Heat Risk Expands; Monitoring the Tropics

Flash flooding risks continue for portions of the Four Corners and Great Basin through today. Severe thunderstorms are outlooked from the eastern Great Lakes, southern New England into the mid-Atlantic through Tuesday. Heat risk increases and expands across the center of the nation and across the Ohio Valley and mid-Atlantic this week. Continue to closely monitor tropical development in the Gulf. 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.