Friday, September 20, 2019

Late Summer Chinooks

This afternoon, the Colorado Front Range is being raked by gusty, southwest winds.  Produced by high pressure over the Desert Southwest interacting with low pressure over the Northern Plains, these winds, downsloping from the Continental Divide, dry out and heat up, comparable to Santa Ana Winds in Southern California.

A dry-line currently stretches north to south through Colorado, just east of the Front Range urban corridor, and will likely produce thunderstorms once it moves into more humid air on the Great Plains.  Here in Metro Denver, behind the dry-line, the gusty downsloping winds have delivered hot, dry, crystal-clear air and we expect another afternoon in the 80s (F).

During snow season (October to May) these winds are known as chinooks or "snow-eaters," since they rapidly warm the urban corridor and make snow disappear from the landscape; much less welcome during fire season, they can turn a small fire into a raging inferno.  Tomorrow, after a cold front moves in from the northwest, the chinooks will shut down and it will feel more like autumn (at least for a day or two).