11:40 AM, Friday, April 28, 2017
The sunshine and low humidity should change rapidly from north to south this afternoon and evening, probably during the early afternoon in Cheyenne, the late afternoon and evening from Boulder County southward. Although it’s well above freezing in many areas now, the dry air should allow for strong evaporative cooling when the precipitation starts, so rain, if any, won’t last long.
4-10 inches mountains, foothills, Palmer Divide area (locally more than a foot in some mountain areas, especially south of I-70)
3-7 inches Colorado Springs
2-5 inches Boulder, Denver
1-3 inches Longmont, Fort Collins, Cheyenne
8-15 inches and windy for southeastern plains (along and south of I-70)
** mainly Friday evening through Saturday morning, longer in southeastern Colorado
What can boost amounts?
The storm is a rather classic setup for big Spring snows but the air over the Front Range Friday morning is remarkably dry. The storm will try its hardest to draw in moisture from the east starting this afternoon, but the really rich moisture may not be able to make it all the way to the Front Range before the storm system begins pulling east on Saturday.
That said, there is a small chance that the richer moisture will make it this far west and boost amounts along the Front Range, but that is probably about a 10% chance. For southeastern Colorado and the Front Range south of Colorado Springs the chance is greater for big snow.
Milder weather should return after a widespread hard Freeze Sunday morning. But current indications are that we may have another period of frosts and freezes around midweek, so be patient with the tender annuals.