12:45 PM, Thursday, October 1, 2015
A weak storm system is headed toward Colorado/Wyoming bringing cooler and more unsettled weather beginning Friday, but the weekend is likely to be neither cold nor very wet.
The best chance for rain, and maybe some thunder, will be Friday afternoon until early Saturday morning. There may be some additional showers Saturday afternoon and evening, especially in the mountains, but a long-duration steady rain is not expected, and sunny intervals are likely over the weekend. Snow level will likely stay at or above treeline, possibly slipping a little below treeline in areas with more persistent showers. Temperatures will likely be close to, or a little below, average (average highs for the Colo Springs-Denver-Boulder-Cheyenne corridor ranges from upper 60s to low 70s).
September’s average temperature was the warmest on record for Denver, Colorado Springs, Pueblo, and probably Cheyenne (but I could not confirm that one yet). Boulder had seven Septembers that were warmer between 1947 and 1963, but these were influenced by a substandard location of the thermometer in those years. Since the current Boulder climate station was established in 1990, 2015 was easily the warmest September. Denver and Boulder also had a very dry September, but not record dry.
Hurricane Joaquin is a category 4 hurricane in the northern Bahamas that poses some threat to the East Coast. However, the most recent model guidance is certainly trending more toward a track that keeps it largely offshore as it heads north.