December and a Hint of January Pattern Discussion

[Ian]

That will make DT and all the WV Ski resorts happy.

Him and Berk are working to salvage Sunday still.

[AvantHiatus]

Euro has 50 below normal temps in WV near the end of the run.

Mindblown, that PV is really going wherever it wants.

[WxUSAF]

Euro has 50 below normal temps in WV near the end of the run.

50!?!  You mean on Day 15?  I don't see that on Day 10.  

[Ian]

50!?! You mean on Day 15? I don't see that on Day 10.

https://pic.twitter.com/FKANjo0UDJ

[snow.]

There will be an area of -20F surface temps across northern tier by early-mid next week. Although it is "rollover" cold it will create departures of -20, or colder, around DC.

 

It is looking pretty promising for that.  I said about a week ago?  that I thought we would have a -15 departure day in the 1st half of december. As you state it looks like there is potential for even colder.   That would be awesome.  The models are advertising insane cold.  i think the potential for a counterfeiting midnight high is there which migh prevent a monster departure but still cold.

[snow.]

Euro has an afternoon high next wednesday in the teens for the western burbs.

[Heisy]

This doesn't look bad for possible snow down the road. Is that shortwave in the southwest associated with the STJ? 

 

 

but let me guess...no snow right?

 

 

 

[Ji]

Euro has an afternoon high next wednesday in the teens for the western burbs.

who cares if its not going to snow

[Bob Chill]

Euro has an afternoon high next wednesday in the teens for the western burbs.

 

It's a wild ride for temps upcoming it seems. If this airmass performs and the cold lingers before the relaxation we are likely to be below for the month through the 15th. It gets muddy after that but a warmup is probably inevitable at some point before the last week of the month. 

[Bob Chill]

Euro  h5 ensemble mean is still trending towards a less bad look d11-15. Flat pac zonal flow from the last couple days is slowly getting replaced with potential ridging (kinda flat in the means) in the SW. Mean trough axis over the conus is basically down the MS river and the east based -nao is definitely there. It's not that great of a -nao but it's negative nonetheless. 

 

Coldest anomalies remain firmly centered in western canada but all of canada is cold. At the very least it looks like the cold delivery mech into the us is not going to go poof if these trends continue. 

[snow.]

Euro  h5 ensemble mean is still trending towards a less bad look d11-15. Flat pac zonal flow from the last couple days is slowly getting replaced with potential ridging (kinda flat in the means) in the SW. Mean trough axis over the conus is basically down the MS river and the east based -nao is definitely there. It's not that great of a -nao but it's negative nonetheless. 

 

Coldest anomalies remain firmly centered in western canada but all of canada is cold. At the very least it looks like the cold delivery mech into the us is not going to go poof if these trends continue. 

 

I blended the 2  top analogs from the Canadian/GFS/Euro ensembles for day 11-15 and got this...it probably will be a bit colder than this might suggest....I think the takeaway is the PAC is no longer the same cold producer that it was...there is a quasi 50-50 but it isn't in great position..but could slow things down slightly....the storm track is to our west...it is a gradient pattern.....looks like maybe a STJ trying to develop too..looks like a cold/warm battle, but unless the pattern gets better the air masses get more stale and the se ridge is more of a player...

 

[usedtobe]

I blended the 2  top analogs from the Canadian/GFS/Euro ensembles for day 11-15 and got this...it probably will be a bit colder than this might suggest....I think the takeaway is the PAC is no longer the same cold producer that it was...there is a quasi 50-50 but it isn't in great position..but could slow things down slightly....the storm track is to our west...it is a gradient pattern.....looks like maybe a STJ trying to develop too..looks like a cold/warm battle, but unless the pattern gets better the air masses get more stale and the se ridge is more of a player...

 

11-15day.gif

Matt, that positive anomaly position also often wets up the west coast with a firehose if the subtropical connection ever get mad and then you often have a period of warmth across the U.S. ahead of the system.   Of course,  that's all speculative as the analogs could change over the next several days. 

[snow.]

Matt, that positive anomaly position also often wets up the west coast with a firehose if the subtropical connection ever get mad and then you often have a period of warmth across the U.S. ahead of the system.   Of course,  that's all speculative as the analogs could change over the next several days. 

 

 

yes..you have mentioned that...it is only a window of time we can have positive height anomalies with below normal temps (what the models are showing after the cold shot next week) before the surface catches up (unless we have a pattern change)..which makes me dubious of how long the cold will last next week after the big shot

[Bob Chill]

I blended the 2  top analogs from the Canadian/GFS/Euro ensembles for day 11-15 and got this...it probably will be a bit colder than this might suggest....I think the takeaway is the PAC is no longer the same cold producer that it was...there is a quasi 50-50 but it isn't in great position..but could slow things down slightly....the storm track is to our west...it is a gradient pattern.....looks like maybe a STJ trying to develop too..looks like a cold/warm battle, but unless the pattern gets better the air masses get more stale and the se ridge is more of a player...

 

 

 

I don't think the period from d12 and beyond will be cold. Just closer to average than I was thinking. My fear was a flat pac zonal for a stretch of +5-10 weather for a week or more was very much in the cards. The look on the ensembles are now pointing towards seasonal temps.

 

If you look at the means, low height height anoms are now showing up around the lakes and northern plains. This is a new trend and probably the first sign that cold can still intrude at times in the east. But I agree with both you and wes that this is not a snow pattern other than a fluke. But it's not a torch either and that's was my bigger worry. 

 

The state of the ao is definitely unresolved. Moreso than I've seen in a while. Winning side of that one wouldn't be a bad thing. 

[WinterWxLuvr]

I don't think the period from d12 and beyond will be cold. Just closer to average than I was thinking. My fear was a flat pac zonal for a stretch of +5-10 weather for a week or more was very much in the cards. The look on the ensembles are now pointing towards seasonal temps.

If you look at the means, low height height anoms are now showing up around the lakes and northern plains. This is a new trend and probably the first sign that cold can still intrude at times in the east. But I agree with both you and wes that this is not a snow pattern other than a fluke. But it's not a torch either and that's was my bigger worry.

The state of the ao is definitely unresolved. Moreso than I've seen in a while. Winning side of that one wouldn't be a bad thing.

Models are struggling, analogs are few, long range prognosticating is going to be rough.

[mitchnick]

odd to see that strong a ridge in Russia this time of year on the day 10 Euro

don't know the exact implications but anytime the cold air is not on their side of the Pole it usually is better for us

http://www.ecmwf.int/products/forecasts/d/charts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa%20and%20Temperature%20at%20850%20hPa!240!Asia!pop!od!oper!public_plots!2013120312!!/

[CAPE]

Been keeping an eye on the GFS ENSM forecasts for the NAO the past week, as there have been some hints in the guidance, This aint lookin too shabby...Hopefully it verifies(and is west based).

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

[Ian]

After this storm is some serious cold, that's for sure. 

 

pedestrian cold

 

[ravensrule]

pedestrian cold

 

gfs_t2max_washdc_63.png

Yea for Minneapolis maybe.

[ORH_wxman]

Yea for Minneapolis maybe.

 

 

Record low max for DCA on 12/11 is 21F in 1917. One of the harder ones to break too as other nearby dates are 23-25F.

[ravensrule]

Record low max for DCA on 12/11 is 21F in 1917. One of the harder ones to break too as other nearby dates are 23-25F.

I will be in Florida so i hope Ian freezes his ass off. He has been begging for real cold down here since he moved here.

[Amped]

GFS D12+ = pac torch

[lsukev]

Coastal from Euro now showing up on the GFS around 18 hours slower

 

[WxUSAF]

I really like the fact that we have an active pattern with juicy shortwaves and an abundance of cold air in our source regions.  No, it's not some sort of --AO/--NAO El Nino like 09-10, but with the ingredients of cold air and moisture in play, I can't envision us ending up with a year like the last couple.  It might not, probably won't be, above average snowfall, but just doesn't feel like we're going to end up really low either.  Just my 2c.  

[Bob Chill]

I really like the fact that we have an active pattern with juicy shortwaves and an abundance of cold air in our source regions.  No, it's not some sort of --AO/--NAO El Nino like 09-10, but with the ingredients of cold air and moisture in play, I can't envision us ending up with a year like the last couple.  It might not, probably won't be, above average snowfall, but just doesn't feel like we're going to end up really low either.  Just my 2c.  

 

 

What I find even more interesting is unexpected results so far. November was supposed to be warm. It wasn't. STJ was supposed to be mainly dormant early on. It isn't. December warm signal was definitely there but forces seem to be fighting it. Long ways to go but I'm starting to doubt we get that 10 day stretch of despair. 

 

Record lows and record low maxes are being set across the us in much greater #'s than highs. 

 

A marked changed happened in February irt to temps. It isn't a "cold" year by any stretch but it is far different that the last 3. Especially in duration of warm spells. 

 

The PV basically moved into and wobbled around eurasia for 3 winters. We never thought it was coming back, And here it is. 

 

The arctic had a big bump year. I'm not going to pretend to know the hows and whys with any details but it's another sign that things are different. 

 

We can look back in early march and assess overall but for now I'm feeling enthused for a fun year. Even if the stormtrack favaors messy. I'm fine with that. If we can team up active split flow and a block I'll be beside myself. No signs of that yet but who knows.

[Bob Chill]

12z euro op quickly destroys our cold d8-10 and pumps an ugly ridge. However, some of this is response to a modeled bowling ball down the west coast and half way down the baja peninsula. IMO this is a typical euro bias in the SW and too far out to worry much about. We'll see what the ensembles say. 

[Ian]

Not quite as cold behind the storm tho Thursday is still subfreezing verbatim.  

 

Is that SW bias still real? I thought it wasn't. 

[snow.]

What I find even more interesting is unexpected results so far. November was supposed to be warm. It wasn't. STJ was supposed to be mainly dormant early on. It isn't. December warm signal was definitely there but forces seem to be fighting it. Long ways to go but I'm starting to doubt we get that 10 day stretch of despair. 

 

Record lows and record low maxes are being set across the us in much greater #'s than highs. 

 

A marked changed happened in February irt to temps. It isn't a "cold" year by any stretch but it is far different that the last 3. Especially in duration of warm spells. 

 

The PV basically moved into and wobbled around eurasia for 3 winters. We never thought it was coming back, And here it is. 

 

The arctic had a big bump year. I'm not going to pretend to know the hows and whys with any details but it's another sign that things are different. 

 

We can look back in early march and assess overall but for now I'm feeling enthused for a fun year. Even if the stormtrack favaors messy. I'm fine with that. If we can team up active split flow and a block I'll be beside myself. No signs of that yet but who knows.

 

 

It is so much better than the last 2....Dec 2004/2006/2011 etc were painful...

[Ji]

Not quite as cold behind the storm tho Thursday is still subfreezing verbatim.  

 

Is that SW bias still real? I thought it wasn't. 

its only real when it warms us up and takes snow away. What happened to the -50 below normal in WV?

[Bob Chill]

Not quite as cold behind the storm tho Thursday is still subfreezing verbatim.  

 

Is that SW bias still real? I thought it wasn't. 

 

I think it is at the really long leads. It's just run one anyways. Take out the bowling ball and the height pattern will likely be quite different. 

 

Honestly, I didn't expect the cold to hang for days and be as impressive as modeled recently. We still don't have a feature to hold cold in past a couple days. Without re-enforcing shots we will warm quickly.