Chinook

blue has taken over

This will be a very good storm for the Colorado mountains, certainly compared to most storms recently. The values shown by the NWS for the plains are probably a blend of models, which predict light snow at various times, mostly focusing on Saturday night to Sunday night. My area got something like 1/4" of snow last night, which is the first snowcover in several days. The GFS and NAM have over 0.4" QPF in the immediate area, with high snow ratios on the Kuchera snow plots, so I suppose we may want to watch and see if snow amounts could be higher. And even in this cold, cold world, Craig, Colorado has -RA right now.

Weather-related disaster in Fort Worth. You guys have probably already heard this on the news if you are from this area.

As of right now, I don't have a lot of confidence in any particular forecast of snow. The only thing I really know is that the mountains will get snow on many of these days, and we may be in a sad situation: we will have cold temperatures be in place, while every other region around us gets snow. Nevertheless, models have some QPF. Somewhere in here, 00z Sunday to 00z Monday, we could get 2-6", as this 0.3" in Fort Collins and Cheyenne could have 20:1 snow ratios.

Fort Collins-CSU had a temperature drop of 24.1 degrees in 10 minutes (5:20 to 5:30PM). As you can see on the image I posted, some stronger easterly winds yesterday advanced the arctic air. We had gusty westerly winds and quickly switched to gusty easterly winds. As of right now, APA (Denver/Centennial) is 20 degrees warmer than DEN. It will be interesting to see if the inversion breaks and Fort Collins or Greeley get up to 32 or something like that.

It is 53 degrees in Denver vs 22 degrees at Fort Morgan. I think the cold air may move westward quickly.

Our fantasyland storms have barely even been interesting for a long time. I'm not posting any fantasy storms unless the Euro has 0.1" or 0.2" of QPF. As for me, I've gotten 14.1" since November 1st, compared to an average of 26.4" for Fort Collins. (1.26" compared to 1.73" liquid equivalent) It seems like the cold air is coming into the middle of the country, and *later* this week may be one of the few times my place will get below 10 degrees for the winter. Even at that, I've hardly gone outside on any cold day since I work from home quite a bit.

I hope this isn't too crazy to post here. The latest development on the models shows a likely 7-8" in 12 hours at Grand Island, Nebraska in a couple days. Messy times on I-80. It's barely a defined surface low, but seems to have a low at 850mb in western Nebraska connected to a jet stream disturbance.

This band of snow in Indiana right now has no stations reporting snow under the band-- only stations to the southwest are reporting snow. Maybe it is just a timing thing, or maybe there is significant virga?

Wind gusts are picking up to 30-50mph in Fort Collins and Loveland.

If you combine the snow totals since about Jan 21-- it looks like one huge 10" storm tracked across the country, after dropping off 2-4 ft at the Sierra Nevada and also dropping heavy snow at Arizona's Mogollon Rim and southwest Colorado.

picture from between Marysville and Bellefontaine yesterday. My sister estimated a total of 9" by today

Sometimes the 120 hour time frame is when the models start to lock on to a storm and get some agreement. In this last couple of days, the 168-120 hour forecasts have been model hell. I think the models are getting closer, but the GFS/Euro are still having some issues determining precipitation with the front. The GFS has some areas of 0.5" QPF from Fort Morgan to Denver, the Euro has some snow bands (or even rain) that are quicker and weaker.

The models are flip flopping too much on this potential storm. I don't really think any model has nailed down the synoptic situation.

The Euro still has 4-9" for our area on Wednesday-Thursday. The GFS does show this storm now, but the pattern of precipitation is splotchy, with a wild 11" near Fort Morgan and 0.4" for Longmont. The comparison of the 00z run vs the 12z run of the Canadian shows wild inconsistencies.

Today's 00z Euro and 12z Euro had some snow for Denver at about 1 week, but that's pretty far out and I don't want to post it yet.

My place has gotten 1" today, with some nice larger flakes right now. I guess that's an improvement from me complaining about stuff. Interestingly, last January my place got 0" of snow, but I ended up with 79.9" for the season. Weird. The Southwest is certainly getting a series of heavy storms, I'm sure putting a dent in the drought that has developed over the past year. Check out this crazy blizzard warning for the Sierras and South Lake Tahoe city. edit: roughly 2" here

Finally, I think the models are coming into agreement with some areas of snow on Tuesday. We may get over 2" on the I-25 corridor with the other upper level low that is following closely behind the main storm of interest for the Midwest

I must say, I am getting a lot more interested in this storm, as the swath of snow may very well go through Toledo and Fort Wayne. One thing to note, the ECMWF/Canadian have a heavy snow axis of over 12" (10:1 ratio) from southern Nebraska out to eastern Iowa or western Illinois. The GFS has some freezing rain for this area. In fact, the Canadian does have some sleet in this area, (northern Missouri especially). I am wondering if that counts as snow on the Kuchera snow plots. The area of concern in the shortest time frame would be heavy snow/sleet/freezing rain areas for KS/NE/IA/MO, with Topeka, Kansas City, Des Moines, and Davenport being the most interesting areas with larger populations.

It is definitely true that the models have caught on to a pretty big shift to a wet period for the West. I would say that this is overdue, and should put a dent in the drought conditions. Still, though, the GFS is putting out a big 0" for Denver.

Since I moved here in 2006, the average December snowfall for Fort Collins has been above the 30-year climatology for the 1971-2000 period. 8.3" (1970/71-1999/2000) increasing to 11.5" (2006/07-2019/20). March snowfall has gone in the opposite direction: 11.8" way down to 6.6".

I found some data that show conflicting answers as to what is likely to happen with precipitation during a La Nina. Check this out. The top two maps will show red/orange with increased precip with El Nino, blue/green with increased precip with La Nina. The bottom two maps show increased precipitation in blue/green for La Nina (and does not include any information from weak/moderate/strong El Nino years.) Colorado seems to be the only area in the country with different colors on the comarisons of the top two maps- and also the comparisons of the bottom two maps. This must mean something like the inclusion November and March is quite important. November to March-- more inclusive, because we get plenty of snow in November and March-- December to February only-- Specific La Nina winters (December to February Only, 1981-2010 climatology) November to March--- specific La Nina years

I must admit, the situation did not look good at the beginning of the fall. There has been a significant (fiery) drought here, and a La Nina incoming. A moderate-strong La Nina does not correlate to high precipitation for southern and eastern Colorado. In some of the most recent weeks have had snow go south of us, like in New Mexico, Texas, Louisiana, North Carolina, Oklahoma, and Arkansas. This happened even without a deep arctic air mass mostly. That kind of thing can happen from time to time with an El Nino, but the situation in the Pacific is certainly a La Nina. As of today, the near-term storm does not look like it is going to bring more than 1" of snow to my place, but a reasonable amount for central-southwest Colorado and some of New Mexico, and rain for Arizona. The models have bigger storm for the Rockies/Plains in about 1 week------ every model has the snow missing Denver. So I'm not pleased.

This upcoming 500mb low, diving toward the desert, will provide possibly 5-10" for a good part of Colorado's mountains, but apparently not much for east of the Front Range. Models have some varying degrees of snow/rain for northern New Mexico.

Interesting and helpful change to Pivotalweather- GFS can show maps for every 3 hours