12:30 PM, Monday, November 14, 2016
The temperature will take quite a ride this week. Record or near record warmth Tuesday and Wednesday will be replaced by much cooler Thursday and Friday, and then probably warmer again by the weekend.
The record high temperatures in Denver are 78 on Tuesday (from 1942) and 77 on Wednesday (from 1941). In Boulder the record highs are 75 on Tuesday (from 1953) and 74 on Wednesday (from 1999). Up and down the Front Range (Cheyenne to Colorado Springs) we are likely to be close or even set new records. With the exceptional dryness in the area, fire danger will be elevated.
The cold front
A strong Pacific cold front should sweep through the Front Range region Wednesday night and early Thursday. Although the temperatures are not likely to be nearly as cold as it could sometimes get in mid November, we may very well see our first below-average temperatures since October 19th! For the mountains and west-facing slopes, some accumulating snow is likely (maybe rain at first in the valleys). There may even be enough to make for winter driving conditions at some of the central and northern passes like Rabbit Ears and Loveland Pass.
Front Range snow??
The storm is coming in mainly from the west, so low level winds are likely to be mainly from the north and northwest, not the from the northeast direction that we prefer for snow and rain in and along the foothills. But there are two things to watch for over the next couple days. 1) There may be a brief period of northeasterly flow on Thursday that would support a period of rain changing to snow. 2) North facing sides of the Palmer Divide and Cheyenne Ridge have a better chance for snow in these setups.
Bottom line: I think there is less than a 50-50 chance for the first 0.1 inch of snow in Fort Collins, Boulder, Longmont, Broomfield and Denver, and only a very small chance in Colorado Springs. But, there appears to be a slightly better than 50-50 chance that the ground will get whitened in Cheyenne and the far south and southwest suburbs of Denver.
As the storm cranks up, there is a better chance for some wet snow accumulation on the northeastern plains of Colorado late Thursday, mainly east of DIA and north of I-70.