Denver’s weather is starting to change ahead of a massive winter storm coming this weekend. Little ripples ahead of the primary system had a rain-snow mix falling across the Front Range on Wednesday morning, and the weather will only deteriorate.
Denver will reach 54 degrees on Wednesday under partly cloudy skies, dropping to 28 degrees overnight, according to the National Weather Service. Snow showers could develop in the mountains in the early evening.
The stronger showers could produce a quick inch or two of snow and create dangerous conditions. Gusty downsloping winds will push winds near 40 mph, making the day a critical fire weather day.
Thursday will have more sun, with a high of 48 degrees and a low of 30 degrees in Denver. Snow will develop in the mountains and foothills later Thursday with light accumulations.
“A large trough which is currently sitting just off the northern California coast will progress towards Colorado over the coming days, eventually bringing a significant snowstorm to our forecast area,” the NWS warned on Wednesday. “This trough will take its time moving across the nation, and that is part of the reason for the high precipitation values it will bring.”
The storm will move into Colorado in earnest on Friday when Denver will have a high of 39 degrees and a low of 32 degrees. The storm should hit in the afternoon, but the timing and strength are still highly variable because the forecast models rely on satellite data. The storm is parked off of the coast, making more reliable weather balloon data unavailable for now.
“The main event that has caught the eye of weather enthusiasts will begin late Friday and into Saturday,” the NWS wrote. “It is also when the models begin to have larger disagreements. What models agree upon is that thunderstorms will develop along a dryline across western Texas to western Kansas as a surface cyclone deepens over southeast Colorado and northeast New Mexico. Meanwhile, the cut off trough will move slowly eastward, providing ample ascent for a long duration of moderate to heavy snowfall across much of our forecast area.”
The models disagree on when the cut-off system will move east and how strong the upslope flow will push the moisture from the Gulf of Mexico into the mountains forcing it into powder.
“The Global Forecast System and Canadian model are more progressive with the cut-off trough and have stronger easterly winds at 700 and 500 MB, meaning there would be better upslope flow. The European Center for Medium-Range Weather Forecasts model is slower with the progression of the trough and has weaker upslope flow.”
Another aspect that causes the high level of uncertainty with this spring storm is where the rain/snow line will be. Southern and Eastern Colorado could see a good amount of rain if the storm shifts north or the area could have a blizzard if it dips south.
“The question is, are the 60 knot easterly winds at 700 MB in the Global Forecast System realistic? It seems unlikely. But could the upslope component of the wind be in the 35-45 knot range for a 12-24 hour period? That is much more likely,” the NWS said. “It is possible the average snow ratio may end up in the 8 or 9 to 1 ratio with this storm. Therefore, the messaging of 1 to 3 feet of snow for much of our forecast area is still on track. Winds will increase late on Saturday and through Sunday with gusts up to 45 mph possible across the eastern plains near Limon.”
The big storm is still on track to bring between a foot and three feet of snow to the urban corridor starting Friday and lasting through Sunday.
Source: Read Full Article