11 AM, Friday, September 22, 2017
Autumn begins at 2:02 PM MDT today and will be accompanied by warm weather. But the first autumn weekend will turn much cooler and may also be wet at times.
A cold front will sweep from north to south through the Front Range region late tonight and Saturday. In fact there may be an initial front Saturday morning and then a stronger push of cool air Saturday evening. Temperatures Saturday should hover in the 60s in the lower elevations of the Front Range and possibly start falling later in the day. Sunday and Monday will probably get no warmer than the 50s in lower elevations.
Although it’s not a great setup for a soaking rain and mountain snow, it is the best chance we have had in a while for widespread measurable rain. Showery rain (and maybe a few thundershowers) are likely to affect some areas Saturday. By Saturday evening the chance for a multi-hour period of low clouds, drizzle, or rain increases. That possibility stays with us through early Monday, but I think there will also be some dry stretches and breaks in the overcast on Sunday. And yes, there will probably be some wet snow above treeline and maybe some flakes down into the upper foothills.