Thursday, April 14, 2016
Energy ejecting from the intensifying storm to our west will bring a cool front and several waves of moderate to heavy rain to the valleys from mid-evening until midnight with snow above 9000′. The precipitation will moderate after midnight with rain showers possibly turning to snow showers in Steamboat.
Precipitation will become heavier Friday afternoon as the cool air aloft destabilizes the atmosphere and brings the possibility of thunder. Rain will change to snow in the valleys during the evening as the storm strengthens significantly. By Friday night, the low level counterclockwise winds will draw substantial Gulf of Mexico moisture into the storm creating conditions that produce a TROWAL somewhere over the Colorado mountains from Saturday through Monday and strong upslope flow over the Front Range. While all of Colorado will receive substantial precipitation, the foothills look particularly favored with 12-18” of snow expected by Saturday afternoon that will make travel on I-70 west of Morrison difficult to impossible. There may be road closures.
Closer to our area, I would expect 1-3” of dense snow in the valleys by Saturday morning with 5-10” on the mountain as the winds turn easterly. While we are often sheltered from precipitation when easterly winds downslope off the Park Range, we can receive moderate to heavy precipitation under a TROWAL.
Models indicate the position of the TROWAL moving around through the weekend, so the periods of moderate to heavy precipitation will likely move around as well with breaks in the inclement weather. The easterly upslope flow for the Front Range, however, will be persistent, and another 12-18” of snow may fall from Saturday afternoon through Monday afternoon, continuing the travel problems on the I-70 corridor.
There may be a decrease in precipitation over our area during Sunday, and current model trends have slowed the storm enough so that the storm does not move east of our area until late Tuesday. Snow showers will continue intermittently through Tuesday afternoon with drier weather still forecast by Wednesday.