11 AM MDT, Sunday, April 28, 2019
At 11 AM Sunday a cold front resulted in a 15-20 degree drop in temperature at Casper, WY. That cold front should move through Cheyenne in the midday hours and then through the Colorado Front Range urban corridor by late afternoon.
Rain and snow is likely to come in several intervals. The first this evening. After a lull, the period with the best chance for snow at all elevations will probably be late Monday afternoon and night. There may be one more round of precipitation Tuesday evening too.
Some showers and thunderstorms are likely to develop behind the front this afternoon/evening followed by some areas of drizzle during the night. Snow above 9000 feet is likely to move to lower elevations by late night, but accumulation, if any, should be mainly above 7500 feet and mainly in the 1-5 inch range (highest above 9000 feet).
Monday and Monday night
The second round of precipitation likely from about midday Monday until late Monday night will occur with the highest amount of atmospheric moisture during the next few days, and the lowest temperatures. Therefore, this period may bring the best chance for heavy snow in the mountains and rain changing to wet snow with some accumulations in the lower elevations. During the period 5-9 inches could occur above 7500 feet, with 3-6″ in the 6500-7500 elevation range, and 1-4″ below 6500 feet.
Tuesday night and Wednesday morning
There may be one more round of rain and snow Tuesday evening through Wednesday morning. It looks like the atmosphere may be a little warmer for this period (than on Monday night) so the chance for additional snow in the lower elevations is small.
With this kind of wet period over several days, the total amount of snow accumulated will probably be higher than the maximum on the ground at any one time due to melting during lull periods.