Saturday, October 21, 2017

Autumn Roars Back

After a week of summer-like weather in Metro Denver, a potent cold front dipped across the Front Range overnight, raking the trees and rattling the windows.  The winds brought in clear, crisp Canadian air and our afternoon high will be twenty degrees (F) cooler than it was yesterday.

High pressure behind the front has settled over the upper limits of the Great Basin and will produce Santa Ana winds across Southern California in the coming days.  Meanwhile, the cold front continues to march eastward and will clash with warm, humid air flowing up from the Gulf of Mexico; this collision will ignite a band of strong thunderstorms across the Great Plains and the Upper Midwest.

Our dose of autumn will be brief and summer warmth will return tomorrow, persisting for several days before snow arrives late in the week.  One sign of our gradual transition to winter has been the annual return of a Harlan's hawk to our Littleton farm; after breeding in Alaska and Western Canada, this dark subspecies of the red-tailed hawk winters across the Southern Plains, from Colorado to West Texas (see Welcome Back Harly!).