FULL STORY: Rare ‘deep freeze’ rain falling on dry mountains of Colorado


On this week’s The Weather Channel’s series “TODAY’s Weather Forecast,” I found a story out of Colorado about a uniquely interesting cloud, previously unseen in the region’s sky.

What you saw above are large pieces of material called periodic clouds. They are often formed by precipitation. They are essential to the regular landscape of Colorado, stretching south down into Utah. They interact with the atmosphere in dozens of different ways that are of interest to researchers and meteorologists.

PHOTOS: Colorado’s rare elemmon variant, dubbed COVID 19

Colorado’s atmosphere of COVID 19 include clusters of patches of ground ice. Rather than snow, they make the ground ice in the early fall and early winter. They’re there for periods of cold weather, and stay all winter long. When you look at the radar images taken over the Basin on this week’s episode of “THE TMS”, they remain visible all through the winter.

RIVER CANYON SUN: Covers all of North Colorado and stretches into New Mexico pic.twitter.com/5BPoVzGqhF — The Weather Channel (@weatherchannel) January 15, 2016

EARLIER SEASONAL CLOUDS: Last year I wrote about the unusual number of moisture clouds we can see here in Colorado in the winter and spring. The increasing temperature content of snow allows a lot of that moisture vapor to freeze, and create a number of these “cankles” that form.

COVID 19 is a rare adaptation of this phenomenon. When we look at the SNOW cover on this week’s radar, it looks big from the southwest to the north. The COVEST image from the last three days shows another type of moisture cloud present in the mid-continent. These are “front-line” clouds: usually they form in the week of December 20th or so. They are usually viewable during the overnight hours around Christmas, or in the new year in early January. These are the bread crumbs of moisture that form in the warmer days of the year. They are light, crisp, and begin to subside on the backside of the approaching polar vortex.

WEATHER FROM THE DARK: But you need not look as far south as these images from Colorado to find the moisture. If you take a look at the far right of these two maps it will show you a new kind of moisture cloud, from the Rocky Mountains to Texas. This is a seasonal prominence (aka faucet) cloud. They form during the early summer when it is much more dry. There’s still some snow where they form, but in much higher elevation these are extremely variable. You will often find sections of drought on parts of the mountains. It is this moisture cloud that produces Colorado’s “lunge” precipitation pattern.

COVENANT SHOWER: This week’s Rockies win was secured when the third storm moving in from the Pacific dominated the picture. If you look at the middle of these maps, you’ll notice three troughs in motion. One of these troughs extends north from Texas into Idaho in the mountains, and spreads southward into Utah and Wyoming. As the colder air moves in this warmer air will penetrate. This is typical of an Arctic-satellite pattern, but the low-pressure trough holding in place in Canada suggests even colder air. The low-pressure trough and the one building up in Canada are the culprit for this week’s storm over the central U.S.

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