Winter Storm Walda: Say it Ain't (April) Snow!

Jon Erdman,Nick Wiltgen Published: Apr 7, 2013, 3:56 PM EDT weather.com

http://www.weather.com/news/weather-winter/winter-storm-walda-20130407

An April Winter Storm

Needless to say, it's been a long, snowy winter for many Americans.
Recent weeks have brought signs of spring to parts of the northern and central Rockies with highs in the 70s as far north as Montana. That taste of spring is about to come to a crashing halt as Winter Storm Walda brings heavy snow, high winds, and a drastic drop in temperatures as the new workweek begins.
(MORE:  Is April snow unusual?)

The ingredients that will be in place this week for heavy snow in the Front Range of the Rockies.

We have a classic spring storm set to pivot out of the West into the Plains.  We've already addressed the potential for an outbreak of severe thunderstorms with this bullish dip in the jet stream.
This same sharp southward dip in the jet stream, lumbering slowly east, looks poised to tap deep moisture from the Gulf of Mexico and pull it north and westward.

Monday's Rain/Snow

Tuesday's Rain/Snow

Wednesday's Rain/Snow

Snowfall Forecast

The combination of higher elevation, strong lift in the atmosphere, and near-surface temperatures just cold enough is expected to churn out accumulating snow, heavy in spots.  Let's lay out the forecast for Walda as it stands right now:
Monday:  Snow, possibly heavy, spreads into the High Plains of Montana, Wyoming, the western Dakotas. Significant snow is also expected in the mountains of western Montana, Idaho, eastern Oregon, western Wyoming, Utah and northern Nevada.
The forecast is a tough one for Salt Lake City, where rain could mix with or change over to snow late Monday into Monday night. Depending on exactly how cold it gets and how quickly, a few inches of slushy snow could accumulate on the valley floor, with some limited impacts on travel.
This heavy snow will likely plunge into the northern Colorado Front Range urban corridor late Monday night. Expect a period of rain and possibly thunderstorms, changing to snow Monday night as temperatures plummet rapidly from the 40s to near 20, leading to a flash freeze. A sheen of ice may well form on roadways underneath the heavy falling snow, making travel extremely treacherous.
Strong winds and heavy snow may lead to some power outages and downed tree limbs.
Tuesday:  Heavy snow likely from eastern Wyoming into northeast Colorado (including the I-25 urban corridor), western Nebraska and western South Dakota. Snow totals will exceed one foot in some areas. Strong winds may lead to blizzard conditions and subzero wind chills.  Some power outages and downed tree limbs are possible due to the high winds.  Significant travel impact likely on I-25, I-80, I-70, I-76 and I-90 in these areas.  Flight delays, cancellations are possible to and from Denver Int'l Airport.