Tuesday-Wednesday Storm Update

12/12/21  Sunday 7:00 am

I keep forgetting to mention a fun fact that most people do not know. The earliest sunset time of the year in Durango has passed. It occurred on December 9th. Many people think this happens with the solstice. It does not. The days will continue to shorten as the sunrises later. The shortest period of daylight occurs in Durango on December 23rd. After that while the period of daylight increases, the sunrises occur later until January 13th.

It varies from location to location. For example in  Telluride, the earliest sunset occurs on December 14th. The shortest period of daylight is December 19th and the latest sunrise is January 10th.

If you are a member of the camp whose motto is:  “whatever precipitation type we get, I will take, we need it”, there are offshoots of that camp that say:  “I don’t want to deal with the snow, keep it in the mountains”. If you think that way, I have some good news for you.

If you want a big snowstorm to crush the lower elevations, this isn’t likely going to be the one. But, I have some news for you too. Currently, all of the models show us in MJO phase 7. There are some arguments about how we are going to get there, but the models say we are headed into phase 8 after the 23rd. That would indicate a colder and wetter pattern, which will probably result in more snow in the lower elevations.

For many months, the GFS ensembles (GEFS) have handled the MJO forecast better than the other models. So here is the GEFS MJO forecast.



The green line with the black dots is the one to look at. The big black dot is today. As you can see, the green line goes into a low amplitude phase 7 (close to phase 6) before it marches back across phase 7 going into phase 8 around the 23rd of December.

If you missed my explanation on the MJO on November 30th and want to learn more you can click the link below. A separate tab will open with the post and you can read it after you finish reading this update.

Understanding The MJO

With all of that being said, another messy storm is on the way. I have not given up hope yet that the system will come in a little colder. It may even stall out and intensify before the frontal passage. Plus, there is the whole “Jeff has to drive in it on Wednesday morning” factor that may favor the storm. We’ll see. The models are not showing any of that. However, they are still showing it as a negatively tilted trough as it comes across the forecast area. As I mentioned yesterday, that usually means the storm will be strengthening as it approaches our forecast area.

Here are the latest forecasted precipitation totals. For snow, multiply times 10 for areas above 8,500 feet. I will worry about the other ratios on Tuesday. These models are still struggling. The precipitation accumulation patterns are a bit of a mess. It may mean that they are trying to figure out the strengthening aspect of the storm. That may be why the higher accumulations are all setting up in the eastern portions of the forecast area.

Euro latest (rapid update version)


Nope! Not happening.

Euro overnight

Better? Still not likely.

GFS latest

There should be more of a southwest flow pattern, but it is more believable than the Euro runs.

GFS overnight run

Better, but still not seeing enough of a southwest flow pattern.


The Canadian is just having a bad day. A very bad day.

If we go back and look at the MJO, you can see a jumbled-up mess of dots on the border of phase 6 and phase 7. This indicates the position of the MJO between Tuesday the 14th and Saturday the 18th. After the 18th the GEFS shows the MJO moving firmly back into phase 7.

The Euro shows a similar pattern, but it actually retreats back into phase 6 for the period. Then, Euro emerges back into 7 around the same time as the GEFS.

My next update will be Monday morning by 9 am. Thanks for following and supporting the site!

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