Courtesy of NCEP WPC. In the top two maps, we can see how temperatures in Colorado and the general Northern Midwest are cooler than those of most of the country. The 500-mb map shows the upper level trough that enhanced lift in the state, allowing for the sustained precipitation throughout the past weekend. The precipitation map shows some 24 hour totals from Sunday for the US. Eastern Colorado received more rainfall than western Colorado.
DISCUSSION: Just six days into the start of fall, Colorado is really feeling the change of the seasons. This past Thursday, Denver reached a record high of 92 degrees as one final summer hurrah. In contrast, Denver experienced highs in the low to mid 50s Saturday and Sunday, and felt some highs in the low 60s yesterday and today – a 30 to 40 degree difference in high temperatures! Along with this stark temperature change, the state of Colorado finally received some much needed precipitation, with rain falling across the state throughout the weekend. Another sign of the sudden change in seasons is the presence of snow. Elevations above 9000 feet received enough snow fall to grant the closure of the roadway to Mount Evans, and ski resorts are already preparing for the season as well.
Why the sudden change? A slow-moving cold front and upper level trough moved into the region Friday. It brought along a cold air mass that cooled Denver with temperatures that are typical of late October/early November. With plenty of moisture, and lift from the cold front, a jet streak, and the mountains, conditions were also perfect for sustained rainfall throughout the weekend. As the cold front continues to move east, conditions are expected to dry out and warm up in time for this coming weekend, with sunny skies and temperatures returning to the 70s.
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©2017 Katie McCracken