Monday Afternoon Update

Published 1/25/21 Monday at 1:30 pm

Sometimes, you have to trust your gut instinct. Sometimes you’re right, sometimes you’re wrong, ask Matt LaFleur. If I am wrong I will have a couple of days to figure out where I went wrong before I prepare for the weekend storm forecast.

I have been complaining lately that the models are under forecasting some of the precipitation amounts. That does seem to be the case again this morning with the GFS, the Canadian, and the German models. However, I am seeing some higher amounts and similarities between the morning run of the high-resolution NAM 3km model and the latest European model run.

My forecast is going to be based on those two models plus the conditions this evening and overnight into tomorrow morning. Basically, the conditions are going to be perfect for snow production. A little can become a lot.

As of the time that I am writing this (11 am), there have been no changes to the Winter Weather Advisories. Which reminds me, I have heard from a few people who want to know why Winter Weather Advisories are being issued instead of Winter Storm Warnings.

The first thing that you have to know is that the rules for choosing one of these winter highlights over another are pretty loose and up for interpretation. They also vary based on geographic location. If we get two inches of snow there may be no highlights issued. If Florida or Georgia get two inches of snow they would likely issue a Winter Storm Warning.  The general rules depend on the amount of snow expected. But other factors include wind, ice or freezing rain and holiday travel, and the time of year.

In Colorado, the general rule is that a Winter Weather Advisory is issued if 3 to 6 inches of snow is expected below 8,000 feet. If 6 to 12+ inches are expected below 8,000 feet a Winter Storm Warning is issued. Above 8,000 feet, if 6 to 12 inches are expected a Winter Weather Advisory is issued. If more than 12 inches is expected a Winter Storm Warning is issued. As I said, the NWS forecaster has the option of taking other things into consideration before deciding which product to choose.

Here is the storm on the surface map. It is likely further east than this by now. But check out some of those temperatures in Southern California and Arizona, like Lake Havasu at 46 degrees!

Here are the precipitation maps.

Euro

NAM 3km

Pre-frontal precipitation could start falling by sunset but the more meaningful snow won’t get going until around midnight. The snow will continue through the night and the morning commute will be pretty ugly. Any remaining melted snow on the roads this afternoon will freeze very quickly this evening so some areas will likely have a layer of ice under the snow in the morning. The snow should stop from south to north around or after 11 am. The temperature in most areas will struggle to get into the 20s tomorrow with many areas staying in the teens.

Here are my forecast totals for tonight through late day on Tuesday:

Aztec, Bloomington, Farmington  1 to 3 inches.

Ridgway 2 to 4 inches

Telluride, Ouray, Silverton (town) 3 to 6 inches.

Cortez, Ignacio, Mancos, Bayfield (at 160) 3 to 6 inches

Durango in town, Pagosa in town 5 to 8 inches.

Mid-elevation areas 7 to 12 inches higher totals possible above 7,700 feet.

Mayday, Purgatory and Wolf Creek 8 to 13 inches.

I know that these are in some cases considerably higher totals than you are seeing anywhere else but there is a method behind the madness, as I described in the first part of the post.

If there are any major changes from the NWS in their afternoon forecast package I will comment. Otherwise, the next Update will be Tuesday morning early.

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