The State of the Atmosphere: Sunday, October 2, 2016

Well, it may not have felt like it, but we just wrapped up the first weekend of October. Conditions around the region were beautiful, with highs in the 70s and low 80s across the eastern plains, and 40s, 50s, and 60s at higher elevations. Below is a look at early afternoon temperatures across Utah, Colorado, and the northern high plains:

Weather5280 Models

We'll be warm once more on Monday before more cooler temperatures arrive for the remainder of the week. You'll recall in our post on Thursday we discussed that the main system this coming week may miss us to the north – this still appears to be the case.

In the animation below we see the trough digging into northern Nevada and Utah on Monday, before tracking northeast into Wyoming and Montana Monday night and Tuesday:

Weather5280 Models

Under this scenario, we see some cooler temperatures by Tuesday and Wednesday as the flow turns from southwesterly Monday to west/northwesterly Monday night and Tuesday (see blues overtake DEN below). Temperature won't be too terribly cold with this initial cold shot, however, with highs both Tuesday and Wednesday in the 60s across northeast Colorado.

Weather5280 Models

Unfortunately, as this low stays north it won't equate to much in the way of rain or snow for Colorado, especially east of the mountains. Here is the latest GFS precipitation forecast (left) and snowfall forecast (right) through Wednesday morning. Notice how dry it is across eastern Colorado...

Weather5280 Models

Instead, our best shot at moisture this week may come late Wednesday into Thursday with a secondary shot of cold air. This front will bring with it the chilliest temperatures of the season for northeast Colorado, dropping highs across the northeast plains into the 50s for Thursday, with overnight lows in the low to mid 30s. In fact, a few of the stronger solutions have had highs struggling to reach 50 for a high on Thursday, something we'll need to watch over the coming days.

The GFS shows a band of precipitation moving through northeast Colorado late Wednesday and into Thursday behind a strong cold front that will blaze into the central plains Thursday and Friday | Weather5280 Models

The big question here will be how much moisture will be available as this second system moves through, and of course if any of it will fall in the form of snow at lower elevations. Yesterday's global models all produced decent moisture and even some snow at lower elevations – today they are all much drier, and show little to no snow down low.

For now, we'll introduce a chance of rain and snow Wednesday night and Thursday morning for northeast Colorado as well as cool temperatures into the 50s for highs Thursday. If some of the stronger, more southern solutions verify, we'll likely see a pretty good chance for some moisture across the region by Wednesday night, as well as likely the first flakes of the season as well. If today's trends continue, however, look for a reinforcing cool shot of air during this period, but most of the precipitation will be limited to the higher elevations of Colorado. Of course we'll keep you updated as the week progresses...


First snowfall prediction contest ends Thursday: Enter to win!


Brendan Heberton

Brendan is founder of Weather5280. He is co-founder of FreshyMap, and develops software for geospatial data analysis and visualization.

Denver, Colorado
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