Chinook

The Day-3 enhanced outlook is very concerning for this region. Maybe this could go into a moderate risk outlook for tornadoes and wind when we get to the event. The severe weather parameters such as the STP will greatly increase from 21z to 06z. The NAM and GFS have much different values for the 850mb wind in the region in this time frame, as the NAM has up to 60kt in E Arkansas but the GFS is lower. Note the GFS has values of STP of 1.0-2.0 in the Louisiana area. That's still impressive, but not as impressive as this chart.

NWS web page "weather story"

The global models have some general agreement on this. There is an open 500mb trough powering up this snow event on possibly Tuesday.

looks pleasant and sunny, with a minimum of snow in this field

Happy Thanksgiving. 72 years ago, Thanksgiving Day was on the 23rd of November. On the 24th, deep upper level low was over the central USA. This drove an arctic air mass into the Ohio Valley. A surface low pressure intensified in North Carolina, then moved north and stalled in Ohio. Heavy snow and blizzard conditions hit Ohio. This was one of the most impactful weather events for northern West Virginia of all time. http://greatlakes.salsite.com/maps/nov2327_1950_sfc_loop.gif

00z ECMWF has a low in Illinois with 34 degrees, wind, and snow at St. Louis on Black Friday. Essentially no model has been very consistent with what's happening around Thanksgiving/Black Friday. anybody know where it's going to rain or snow?

It's kind of funny the 10:1 to 12:1 is still quite common even when the models with Kuchera snow ratios calculations say that won't happen. Another idea I had over the last few years. With streets that don't receive any plowing or salting, the total liquid equivalent of the snow is pretty much the main factor for how much snow/ice is packed onto the street after a day or so, given temperatures below freezing. Then, of course if it's 60 degrees the next day, that total liquid equivalent goes into puddles quickly.

looks like 2.0-3.5" at Fort Collins and Loveland with maybe 10:1

In all respect to Jeb walking, I have called this activity "Wethafella Walking. " At the time, Wethafella was a retired, or nearly retired guy from Boston who went out on fun walks during blizzard conditions in Boston, back in the days when I was relatively new to the forums.

1/8 mile measured visibility

It reminds me of a hurricane, although possibly only 10 kt to 30 kt winds within the circulation(s). One other mesolow was over by Alpena earlier.

There have been snow reports of 1.5" to 4". The temperature is 16 degrees in Denver. There are light snowfall rates, with a few bits of heavier snow rates around Boulder and south Denver.

This shows the temperature ranking on the late summer to fall heat wave: #1 warmest Aug to Oct, basically for Washington, Oregon, Idaho, Montana.

There is a winter weather advisory for the Front Range

NWS-WPC has 2"-3" of total QPF (120 hours) just offshore from Jamestown NY/Erie PA with 1.9"-2.1" for Erie and the Southtowns of Buffalo.

Here are the local storm reports for the last 48 hours.

December-type weather is happening now, with continuing lake effect snow in the area. There were many pleasant sunny days recently, even multiple days over 70 degrees. The last 30 days have been roughly 4 degrees F above normal over most of us on the sub-forum. I saw some decent sized snowflakes yesterday, with what could have been a snow rate at least 1/2" per hour. It wasn't really cold enough to get 1/2" accumulation for more than a half hour or an hour. I saw some large aggregate snowflakes of 1/2" width or better, so that's pretty rare. At the end of the day, the ground was really too warm for accumulation

tornado warning for downtown Durham.

interesting tweet that I saw retweeted by Jim Cantore

hand-picked observations from 0650z to 1050z

Here is a cross section across the Midwest. The cold front is on the left, the warm sector is in the middle, and the warm front is on the right. The black lines represent potential temperatures and you can see a little higher slope of the frontal surfaces with the cold front. Colors are frontogenesis. You can see the 0 degrees C isotherms (purple dotted lines) near the ground on both sides.

It's a pretty good weather day in Ohio, with completely sunny skies in the state. There are only easterly winds in Ohio at this time. In the late fall, easterly winds typically go with clouds, below normal temperatures, or rain.

second EF-3 tornado, which includes the preliminary storm survey information that I saw

tornado track of the earliest EF-3 on Friday

So, I guess 3 ft of snow fell since September 30th in WA, OR, ID, MT, WY, and CO, with more coming.