Today and Sunday
The cold front I mentioned yesterday is still meandering south triggering the on and off snow to our north. This should come to a (temporary) end this afternoon. The dynamics are in place so as I said do not be surprised to see light snow or flurries on Sunday as well.
Monday and Tuesday
I am pretty confident in the snow for all, there is some question as to how late it will start on Christmas. The GFS is now showing snow by late morning and getting very heavy after 5 pm through Wednesday around midday. Remember, the GFS is always too fast. Nearly every storm we get timing corrections in the models in the 72-12 hour period before it arrives. The best case scenario would be a cloudy morning with light snow starting late in the afternoon with the heaviest snow beginning around 10 pm. That would make a huge difference for higher snow ratios (less precipitation produces more snow).
That being said here are the details I am still trying to work out:
Does it wait until Christmas or will we see snow sooner?
The models are trending toward bringing an initial piece of energy overnight Sunday into Monday morning for several hours before ending Monday afternoon. This would not be a significant event, rather a heavy flurry event with some favored areas accumulating an inch or so.
What happens after this system moves out of the area late Wednesday or early Thursday?
The models are still trying to decide where to set up the storm as it departs our area. This will be important to Denver and Front Range travelers. It will be a matter of how far east it sets up. Some people in NE Colorado, SE Wyoming, Western Kansas, and Western Nebraska will get hammered with this storm.
Will we get more storms before the end of the year?
Probably, 8 days ago I wrote that I was expecting storms between the 23rd and 28th. The GFS has been showing this for a long time. Lately, of course, it has honed in on Tuesday/ Wednesday, but it also is trying to bring through another storm around the 28th and is showing another around the 31st. My confidence is just starting to increase for the 28th but I am still very unsure of the 31st. Those of you who have lived here a while are familiar with that type of pattern where for a couple or more weeks we get into that 3/4/7 day pattern of storms. The GFS as I have mentioned in the past is lower resolution than the Euro. What I haven’t mentioned is the resolution drops even lower after 240 hours (10 days). So even though it is showing me this big storm around Jan 1st-3rd, it is past the 240-hour higher resolution window so I am not comfortable with it.
The GFS had a great run this morning, the last couple runs before it were not quite as good looking as this. I will say when the GFS has a low accumulation in the Christmas storm it makes up for in the storms that follow. This is common, it is determining how to divide up the energy and moisture. Here is what it has through Thursday morning.
The Euro is just out and has already made an adjustment for timing and is bringing in the storm later on Christmas close to early evening. It hints at a little piece hanging around until Friday. In other words, it does not really show another storm for the 28th and keeps things going. Here is what it shows through Friday.
Don’t you love it when the Southern Mountains get more snow than the Northern and Central! As I said it’s very encouraging, but we still have 12 model runs of the GFS and 6 of the Euro, things could still change either way.