A Better Look At Wednesday’s Storm

12/11/21 Saturday 6:50 am

I got some great sleep and woke up recharged and ready to try to figure out the next storm!

If you haven’t looked at the temps around the region, it is cold. Here are a few highlights at 5:30 am. The temperature will continue to drop for the next 90 minutes so it will get colder.

Silverton -17

Pagosa -10

Telluride -5

Vallecito -8

Bear Creek -10

Telluride -5

Forest Lakes -3

Lightner Creek -7

Lake Durango -5

DW2 -2

Hesperus -3

Mancos -4

Oxford -3

Most of the rest of the forecast area is in the single digits above zero.

Yesterday I mentioned my “high level of confidence” in the next storm. It was not because I am so confident with my forecasting ability, it is because I have a late morning appointment in Cortez. It is one of those situations where if I was able to be home and “enjoy” the storm, it would probably miss us. But instead,  I will be the guy I tell everybody not to be, the guy trying to drive through the thick of it.

I have a very capable well-equipped SUV, so I will be fine. I have been known to storm chase in the winter (shhhh) in my past so I am not concerned, but, you get the point.

One thing that was more pronounced in the overnight model runs is that, at the moment, it looks like the storm will be in strengthening mode just as it comes into the forecast area. This could change, we will see.

You can tell when a storm is strengthening or weakening based on the trough position. A trough can be “standing up”:  straight up and down like this:  I  or it can be positive like this:  /  or it can be negative like this: \. This will make sense in a minute. Read on…

Positively tilted troughs are in a weakening stage. Stand-up troughs are neither strengthening nor weakening. Negatively tilted troughs are strengthening. Negatively tilted troughs can bring high wind gusts, and convection (thundersnow and lightning). Guess what I am going to show you next.

Here is a regional view of the incoming storm Wednesday morning at 5 am.

The red 546 line shows a snow level of approximately 6500 feet or higher. Everything between the red 546 line and the red line to its right should be snow above 6500 feet.

Moving left, you will see the blue line. That is the “540 line”.  Anything between it and the red 546 line to its right should be snow down to 5000 feet.

The next line is a yellow line that I added. It is at the same angle as the other lines around it. That shows it is a negatively tilted trough ( \ ). It is a strengthening storm.

Here is a closer view of the same thing, 3 hours later at 8 am.

Here are the latest forecasts for total liquid-equivalent precipitation.

GFS–By the way, the actual total liquid-equivalent precipitation that downtown Durango received from the last storm was 1.01 inches.

Here was the last GFS run before the precipitation started Thursday morning.

The difference is the storm duration at this point. Interestingly enough, strengthening storms at times will stall out, increasing the duration of the precipitation (similar to what can happen with hurricanes).

Here is the latest Euro

There are some problems with this run. This precipitation spread is highly unlikely. It also does not match up well with the thickness parameters (red and blue lines) I showed you earlier. This tells me the Euro is still thinking through the strengthing possibilities of this storm. I am already anxious to see the next run.


This made me want to check this operational run against its ensemble mean (average of the runs from its family members)

Canadian ensemble mean (Colorado view)

From this, I can see the operational run is in poor agreement with its members.

It is not usually a good idea to check wind forecasts from 5 days out. But, here is the forecast for maximum wind gusts for Wednesday.



My next update will be Sunday morning. Thanks for following and supporting the site!

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2 thoughts on “A Better Look At Wednesday’s Storm

  1. Frank Masiarz

    Wonder if you can include discussions/predictions of temperatures along with precipitation considerations. It is 2.5 degrees right now at intersection of CR 228 and 502. Is this Arctic air pulled down by the jet stream ?? Polar express chill ? Seems very unusual in my 13 years of experience here. Thank you !!

  2. Deb Wykoff

    Love your explanation of why you are confident of your forecast! That’s the real reason I trust your forecasts – science + how the world really works!

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