Published at 12:40 pm Thursday 1/21/21
There is decent agreement among the models on the timing of the systems between Friday and Wednesday. After Wednesday the GFS is pretty quiet relative to the Euro and especially the Canadian (more on that at the end of this post). The GFS’s forecasted precipitation totals are trending up slightly but as you will see, there are huge differences after Wednesday.
Since we have a pretty good agreement on timing through Wednesday, today I will share the forecasted precipitation totals for the weekend (Friday morning through Monday morning). Then I will show the additional totals Monday morning through Wednesday. Lastly, I will share the 10-day forecasted totals with the Canadian going crazy. No, I don’t think the Canadian is correct for days 6 through 10. I am only posting this as an example of why to not trust just one run of one model. That and the fact that is fun to look at, it is kind of like fantasizing about winning Mega-Millions or Powerball.
For today and tonight, there is a slight chance of light snow or flurries in the higher elevations. I do not expect any accumulations.
On Friday moisture will start streaming in with SW flow in advance of the first wave of moisture. Light snow could break out in the afternoon and become more steady throughout the day on Saturday. Snow levels may briefly rise to 7,000 feet, but colder air will eventually spill in lowering the snow levels.
At some point, there may be a brief lull before another wave of snow comes in with colder air sometime on Sunday. Monday we will be in between systems. Later on Monday or early Tuesday, another potent system will come into the area, wrapping up sometime on Wednesday.
I will start with the Friday through Monday period. I am showing liquid totals, but the models are showing mostly snow in all areas. I am not yet comfortable forecasting SLRs (snow to liquid ratios) at this time.
Euro Friday morning to Monday morning
GFS Friday morning through Monday morning
Canadian Friday morning through Monday morning
Now for the additional precipitation from Monday morning through Wednesday morning.
Euro additional Monday morning through Wednesday morning
GFS additional Monday morning through Wednesday morning
Canadian additional Monday morning through Wednesday morning
Up to this point, there are some similar totals, even with the GFS once again struggling with lower and mid-elevation totals.
Here are the 10-day totals from the models
Current Euro 10 day totals
But just 12 hours ago the GFS was showing this:
GFS current 10-day totals
GFS 12 hours earlier
Canadian run 12 hours ago, I have reversed the order for emphasis. This is using the snow parameter of 10 inches of snow to 1 inch of liquid. This is not the crazy run.
Here is the crazy latest 10-day snowfall forecast from the Canadian that just came out. No, I don’t put a lot of faith in the anomalous run, but it is fun to look at!
We had a similar thing happen back in December 2008 but I think it was (only) around 40 inches in town over 7 to 10 days town instead of 57. I will say it again, this is not likely to happen, but it shows you how far apart the models are after next Wednesday. This is more of a wishcast, than a forecast.
With the decent consensus among the models through next Wednesday, I would not be surprised if we saw some early highlights (warnings and or advisories) issued from the NWS as early as this afternoon or tomorrow morning.
Next Update Friday, as always thanks for following and supporting the site.