More spotty snow possible, but cold becomes the bigger deal

Published: Dec. 12, 2022 at 6:04 PM MST
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GRAND JUNCTION, Colo. (KJCT) - All of this week will be more cloudy than night with brief appearances by the sun. There are several small chances for snow from small disturbances moving over the cold air, but there’s no one day when big snow will fall on the Western Slope. Highs will be in he upper 20s to lower 30s. Lows will range from single digits to teens. Most of Western Colorado won’t warm back above freezing until probably next Monday at the earliest. Even though snow is possible this week, the cold will be the bigger deal.

Snow Socks The Mountains

Our storm system arrived in the early morning hours of Monday. As expected. It brought plentiful snow to the mountains, including to the Grand Mesa, the Bookcliffs, and the Colorado National Monument. As expected. Then the mountains put the blocks up for the valleys. As usual, but no necessarily what we expected. The little bit of snow that has fallen around Grand Junction and down Highway 15 through Delta and Montrose has melted... and that’s in the areas where snow has fallen at all.

Why The Valleys Missed Bigger Snow

So what happened? Low pressure approached from the west. Wind flows counter-clockwise around low pressure. While that’s true, it’s more accurate to say that wind spirals counter-clockwise toward the center of low pressure. The wind converges near the low pressure center, and forces air to rise over the low pressure. That rising air is necessary for the formation of clouds and precipitation. Now let’s include the mountains into this equation. The air flowing into the low pressure is pulled down the slopes of the mountains. Remember, we need air to rise for clouds and precipitation to form. The air that flows down the mountain slopes actually prevents clouds and precipitation from forming by drying and warming the air. The downslope wind is always there. The question is when is it strong enough to overcome the strong rising air caused by the low pressure itself. Most recently, the answer to the question is TODAY. That’s why the snow generally choked over the valleys here on the Western Slope.

Snow May Still Be Possible

Here’s where things change... as the low pressure tracks east of us over the mountains, the wind will turn around. Wind will be pulled up from the valleys tonight and Tuesday, and it will spiral into that low pressure center. The upslope wind should be enough for snowy spots, even over the valleys, but snow will still be most abundant over the mountains. That means the snow is not necessarily over, but we’re not all guaranteed to get more snow than has already fallen.

Our Next 24 Hours

Tonight will be cloudy with a chance for occasional snow. We’ll cool from 30s to 20s this evening. Low temperatures by morning will be near 22 degrees around Grand Junction, 20 degrees around Montrose, 21 degrees around Delta, and 11 degrees around Cortez. Tuesday will be mainly cloudy and cold with a chance for occasional snow. Much of our area won’t warm to freezing. High temperatures will be near 33 degrees around Grand Junction, 30 degrees around Montrose, 32 degrees around Delta, and 32 degrees around Cortez.