Friends, make no mistake about it, Christmas will be spent in the deep freeze this year. The 18z GFS develops a monstrous 1066mb high centered over Rapid City, South Dakota Christmas night. Like it or not, that is going to get your attention in a negative way.
Why should you care about a 1066 high or just how extreme the pressure is! Because the higher the pressure the more dense the air mass is and the colder it can get. As it stands now, the highest barometric pressure ever registered in the contiguous U.S. is 1064 millibars measured at Miles City, Montana, on December 24, 1983. That extremely high pressure brought one of the coldest Christmas holiday's for much of the country east of the Rockies. It was the coldest Christmas in northeast Ohio and northwest Pennsylvania and blizzard conditions occurred in some area as well. Need I say more.
While we don't have the fine grid details, it's pretty much a given this Christmas has the makings of the coldest since 2000.
While we're a good 5 days away from the advertised plunge to bitter cold, there will be a few tweaks going forward but in general there is good consistency that the yule log this year needs to be bigger than in most, especially compared to recent Christmases. Here's what the latest GFS shows for highs Christmas day. Sub-zero for many!
The GFS has this for lows Christmas morning. If this holds it would be one of the top ten coldest.
Wind always make things feel much worse and the GFS has this for wind chills.
It's just a bit too early to buy into the extremely harsh cold the GFS is showing but it certainly is on the table as a worst case scenario. Hopefully the trends in coming days are not so harsh.
The other issue of concern is a snow producing wave that brings the cold into the Midwest Thursday/Thursday night. I'm confident most of the heavier snow with the wave will stay north of my area so that's one less issue to deal with. However, some light accumulations are possible, especially north of HWY 30 where an inch or two is possible. Here's the latest snowfall forecast through Christmas on the GFS.
OK, If you haven't gotten the message, be prepared for bitter cold conditions in the time frame surrounding December 24, especially the 25th. Snow of some magnitude is likely December 21st/22nd, heaviest across northern Iowa, southern Minnesota, and Wisconsin. Barring some radical changes, most or my area will see just enough of the white gold to get a dusting south to perhaps an inch or two north. That is all for now. Roll weather...TS