Chinook

Mostly, you don't want Jim Cantore to come to your town, because if he does, a hurricane will blow down your house.

That's so weird. I can't get Radarscope to switch to FTG radar data either. The data is definitely out there, as it is loading on GRLevel3.

Now the NAM is somewhat respectable compared to the global models, in terms of higher snowfall totals. Sometimes I don't know what it takes for our premiere US regional model to actually forecast snow for the Front Range. I don't think we've had so many posts in the Mountain West discussion in 24hrs+ in .... forever. It looks like now I can say that the snow/rain will develop east of I-25 tomorrow and rotate west over the next 6 hours to fill in the entire area, as the 700mb 0C line will stay in eastern Colorado. A bunch of this rain will push north into Nebraska. The colder 700mb temperatures of -3C to -7C will be just enough to keep the precipitation as snow near I-25. I have kind of not looked at a bunch of the details with the radar/precip rate as each model had some different variations of this dynamic storm.

high precipitation supercell (non-tornado warned now)

new possible tornado east of Lubbock, TX

The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Far east-central New Mexico Northwest Texas * Effective this Friday afternoon and evening from 320 PM until 900 PM CST.

latest NWS digital forecast-- when values of 26" are hard to read due to the color scheme, but you need to know... Still, probably some adjustments in the forecast to come in the next 18 hours or so. I guess there is the kind of interesting question as to how much snow affects northwest Nebraska, as opposed to rain.

A couple of the models are showing more evidence of a barrier jet now, which could provide Fort Collins with the 35mph or blizzard-level wind gusts. This is a low-level jet that's aided by stable air moving towards steep mountains. As for other instances of a barrier jet, this can happen in OR/WA coasts as the oceanic air bumps into the coast ranges, with stronger storms.

Alaska... or Denver?

Our first enhanced tornado threat in the Spring season. This is a possible pre-storm environment near Childress TX tomorrow. There is some veer-back-veer, but many indicators that supercells could be impressive. As of right now, the NAM has values of about CAPE=2000 J/kg, SRH=250 m2/s2 and deep layer shear=70kt, for perhaps the most favorable area. Storms may move towards better SRH values.

There's no way 9" will verify. The Canadian has 2.0" to 3.9" for central Larimer County, the Euro, 2.0" to 2.91", UKMET 2.0" to 3.86".

The GFS throws in so much warm air that has rain at 4800ft - 4900 ft at Greeley. The Euro/Canadian/UKMET have significant snowfall values at Greeley, though.

Did the models forget how to forecast real CAPE?

The 00z Euro still has a very significant amount of snow for the area, particularly near and east of Cheyenne. The GFS does have much more for Larimer/Boulder Counties. As for most of Wyoming to the Black Hills, there is a first storm that is happening right now. So the snow totals reflect both storm systems.

For the weight of snow on rooftops, basically QPF would matter, and the ratio wouldn't. Of course, that's not the only factor, but we are starting to get to a point where weight could collapse some roofs.

These are the ensemble plumes for Denver (DIA). Even if we are at the ensemble average of 2.78", that's 27.8" with 10:1 ratios, or 25.0" with 9:1 ratios, as the value of the snow-liquid ratio would get lower as the snow packs down under its own weight. And, of course, there 100% chance that the total QPF will be higher as you go to 6000-7000 ft.

I got kind of chilly while taking these pictures. I figured it was nearly 70 degrees in the daytime, so I should wear a t-shirt to take sunset pics. Nope. 55 degrees and windy

I wasn't able to get on the internet yesterday evening, because Comcast broke down or something. Now the GFS has 58" for me!!!! Better go to the store. Again.

This could be 1.15"--> 13.8" of snow at a 12:1 ratio in *just* 24 hours. I am really hoping that none of this happens on Thursday.

The Euro has over 20" from Denver all the way over to the Oklahoma panhandle.

We may really have to watch this one. The normally stingy WPC 168-hour values have upped our area to 0.3" - 0.7" of QPF for the week (0.9" for the Palmer Divide.)

Possible scenarios-- the models are not really in agreement, but snow could happen on Thursday, Friday, or Saturday if it does happen.

Rain

anybody know why the SPC mesoanalysis shows the radar with only blue/green colors with some actual values of 40-50dBz detected on local radars?

We are getting closer and closer to March. My thinking is that generally moderate La Nina winters should correlate with a higher than average number of tornadoes in the USA for the season. As far as stronger (negative) MEI numbers, years such as 1999, 2000, 2008, 2011, and 2018 should be similar to this year, at least as January and February numbers. Possibly even 1996 could be an analog for a La Nina. total tornadoes / number of F1+ or EF1+ 1996: 1173/430 1999: 1339/530 2000: 1075/352 (much weaker year for F1+ tornadoes) 2008: 1692/707 2011: 1703/909 (outlier year) 2018: 1123/501 perhaps my best guess for the activity of the year might a prediction of EF1+ tornadoes as an average of these F1+ or EF1+ numbers, with less weight toward the 2011 number.