A Mountain Wave Event West of the Colorado Park Range

During the overnight hours of 22-23 April 1999 wind gusts to 40 ms-1 occurred west of the Park Range (3000-3700 m MSL) in northcentral Colorado toppling numerous pine trees and damaging at least six homes in the vicinity of Steamboat Springs (2100 m MSL). The lower and middle tropospheric wind flow during the windstorm was atypically east-to-west in response to a quasi-stationary low over southern Nevada. This event showed similarities to the 25 October 1997 Routt National Forest blowdown where 20,000 acres of old growth forest were devastated by wind gusts in excess of 50 ms-1. The synoptic and mesoscale environment of the 22-23 April 1999 windstorm, through analyses of various National Centers for Environmental Prediction (NCEP) models, Regional Atmospheric Modeling System (RAMS) forecasts, and observed conditions, will be discussed. Attention will center on surface pressure, wind, and stability forecasts produced by the high-resolution RAMS model. Comparisons will be made to the 25 October 1997 Routt National Forest devastation and post-storm research in an attempt to aid operational meteorologists in forecasting these rare events.