10:20 AM, Saturday, May 9, 2015
Today and tonight is the peak of this storm and it will have an impact with heavy rain and flooding, and heavy wet snow making it down to the urban corridor.
Showers and some heavy thunderstorms (snow above 8000 feet) will continue today. Don’t expect the breaks in the action to last very long. As the upper level storm system moves through southern Colorado the wind through a deep layer will turn east, then northeast and then north. That should result in a large area of steady precipitation, especially from the Palmer Divide area northward to eastern Wyoming. Many creeks are at bankfull and may exceed floodstage today. The runoff to the creeks will start to decrease this evening as rain changes to snow in the Front Range foothills and the Cheyenne area. The rain will likely change to snow in the Denver-Boulder-Fort Collins corridor by midnight. The changeover in Colorado Springs may not occur until after the heaviest precipitation is over, so the chance for accumulation there is smaller. Toward daybreak Sunday the clouds and snow are likely to become more intermittent in the Denver-Boulder area too
Rain + liquid equivalent of snow:
A large area with and additional 1-2 inches is likely from the Palmer Divide area northward into eastern Wyoming Saturday afternoon and night. But local amounts of 2-3 inches are possible in the vicinity of thunderstorms within this area as well as the southern Front Range and southeastern Colorado. Be alert for flash flooding.
An additional 10-18 inches in areas above 9000 feet (mainly from I-70 northward) and in the mountain ranges of Wyoming.
6-12 inches in the Cheyenne area and the Front Range foothills between 6000 and 9000 feet, and the Pikes Peak region.
1-6 inches (very variable) for the Denver-Boulder-Fort Collins corridor.
Impacts: With trees leafed out even a small amount of wet snow can cause damage to trees and power lines. Be careful around tree damage, and be prepared for power outages.