Sunday, June 7, 2020

Summer Chinooks

During the colder months of the year, the Front Range urban corridor is famous for its downsloping "chinook" winds, which dry and warm the air and melt any snow cover that may exist.  Producing spring-like conditions in the middle of winter, these winds are welcomed by most.

Today, following severe thunderstorms and destructive winds yesterday, Front Range cities are experiencing gusty, southwest winds, produced by high pressure over the Four Corners region and low pressure over the High Plains (currently centered over west-central Nebraska).  As they descend from the Continental Divide, these strong winds produce hot, dry air that evaporate soil moisture and push afternoon highs well above normal (near 90 degrees F today).  Of course, they also dramatically increase the risk of wildfire in areas that have not received much snow or rain this spring.

While winter chinooks are generally regarded to be beneficial, summer chinooks are, for the most part, unwelcome.  Here in the semiarid ecosystem of the Front Range, where the intense Colorado sun presents its own challenges, we do not need hot, desiccating winds.  Fortunately, this atmospheric wind machine is expected to break down overnight and the next Pacific cold front should arrive tomorrow evening, bringing cooler air and another chance for rain.