Chinook

Montana is 50 degrees warmer than yesterday

I measured 4.5" last night, and this morning it didn't seem like a lot more. This morning I had to resort to measuring snow on top of snow, or snow on top of objects. So that's kind of bad. CoCoRAHS has some 4.5" values in Loveland, and also one measurement of 7.1" Most of Fort Collins had 5". snow basins: the South Platte basin has gone from 59% of snow water equivalent on December 8th to 122% today. 129% in the Upper Colorado River basin today. Everything in the West is above 100% except for up near Great Falls, MT, and Pueblo (upper Arkansas River basin).

Once again, my super color scheme that shows relatively small changes in reflectivity. Narrow bands of snow make you think the mountains are blasting out lake-effect snow.

Pine Bluffs, WY, east of Cheyenne, already got more than 10". For my place, maybe 1/2" per hour for 4 hours, or something like that. I'll check later. It gets harder for me to measure snow without the base layer as the grass.

It's getting into Denver now, with 1/2 mile visibility at Erie and BJC

Now upper and lower Larimer County have winter storm warnings, possibly for different reasons. I think the reason for the W.S.W. for lower Larimer County is higher winds, which is kind of surprising since it isn't windy yet. It isn't snowy yet, either.

Each global model has somewhat more than the NAM QPF of 0.2" for Fort Collins-Loveland-Greeley.

It looks like there is a chance of snow for northern Colorado on Wednesday. It will be with a WNW flow aloft. It could perhaps favor Cheyenne and western Nebraska. It's kind of one of those wait-and-see situations. edit: 00z GFS is kind of nuts for Cheyenne to Fort Collins, hmm, 0.52" of preciptation and 11.7" of snow... 22.5:1 snow ratio. sounds high.

For those interested, it's my first time making a cross-section plot of the frontogenesis, which is highly aligned with upward vertical velocity. The cross-section here goes through the cold air damming zone and snowstorm. You can see the chunk of cold air sitting just east of the Appalachians, with a small zone of temeperature inversion.

I measured 8" in a couple of places. So that's a good one, in my book. I could post pictures, but they are much like other pictures I've posted in the past. As for the observed snowfall graphics on Pivotalweather, it comes from the NOHRSC. I would imagine they will have to do a correction for 24-hr snowfall amounts in Colorado, as probably some more correct values will show up on tomorrow's analysis.

This is a vertical cross section directly through the storm from north (left) to south (right) showing a huge difference in temperatures in the whole atmosphere, and the upward vertical velocity areas (pink) above the slanting frontal surface. You can see the temp inversions with the shape of the 0C isotherm, -12C isotherm, -18C isotherm.

current radar, with alternate color table making 25-30dbz look like red and magenta

Happy snowy New Year to everybody! Finally, the snow drought is over. Fort Collins, got, officially 0.7" in November, which was the only snow up until yesterday, I believe.

I changed the GRLevel3 color palette to make the colors look really wild

snow is starting in the Denver metro area.

We got a snow band develop east of the mountains here at 8:00AM. It is officially starting for my area! Some accumulation on the grass.

Overlay of 700mb winds/temps/RH for a time frame likely the middle of our storm

I guess the 500mb predictions changed just enough overnight to have 4 major models predict a bunch of snow for NE Colorado. I don't know if the big change will really be accurate.

GFS/Canadian/UKMET have seriously changed

I am in Ohio. Rain changed over to big flakes just a short while ago! I'm east of the "red blob" at Fort Wayne (high reflectivity due to partially melted snowflakes) Rain was changing over to snow in Toledo and southward to Findlay.

It's definitely going to get colder at that time, with a chance for snow on 12/31 and 1/1. It is most likely I will be back to my place before the colder weather hits, so that will be nice. Who would have ever thought I would have to wait until (maybe) Jan. 1 or later to see just 1" of snow in Fort Collins or Loveland? I've seen rain twice since I've been in Ohio. It seems so strange to have a wet muddy lawn, wet roads, or fog. I saw a tweet that a University of California research station at the high Sierras has 155" for the month.

There has been a squall in western Colorado, with various measured wind gusts of 45mph to 80mph in the snow. Temps are slightly above freezing at Rifle and Grand Junction.

I got my flight back from the Midwest on 12/30, but I don't see any precip on the models, east of the mountains, yet. Definitely some interesting things at 500mb in the West, though. Apparently Fort Collins-Loveland reported -RA today, certainly weird for December. Lots of precip happening in the Southwest today, with over 1" of rain reported in and around Phoenix.

I have been checking the weather forecasts in the Midwest, since I will be in Ohio. I am about 99% sure that I will see a raindrop, the first raindrop I will have seen in months. Or maybe even a snowflake. In fact, the Rocky Mountains look pretty gray. I checked the 18z GFS and 12 ECMWF for Christmas day, and they have a bigger disagreement in WI/MI. The 12z GFS and 18z GFS go up above 6" of snow (0.6" of QPF) for mid-Wisconsin and mid-lower Michigan. The ECMWF has much less, about 1" of snow (0.1" of QPF) for just a bit of Wisconsin, and the surface low pressure is less amplified.

Good point. We've definitely had some much lower temps in late January, but there's just enough warmer downslope days to balance it so it's just a slight bit warmer in the averages in late January. I'm going to see rain soon, but not here.