December Mid/Long Range Discussion

[Eskimo Joe]

2 minutes ago, GATECH said:

How much snow did DCA get from Jan 3, 2022....I am 11 miles south of DCA and got 11" and am pretty sure we were upgraded to a WSW from a WWA.

 

3 minutes ago, weatherbook said:

D.C. had a winter storm warning on Jan 3, 2022.  I measured about 8" at the Tidal Basin.  It was a classic D.C. snowstorm.

 

Thanks for the clarification! I love the iembot website, but sometimes there are a few data holes, especially when NWS changes from advisory -> warning during the event.

[GATECH]

4 minutes ago, Eskimo Joe said:

 

Thanks for the clarification! I love the iembot website, but sometimes there are a few data holes, especially when NWS changes from advisory -> warning during the event.

[nw baltimore wx]

Does that upper level feature rotating through Monday night/early Tuesday on the gfs have any potential?  Looks lame on the surface but not too bad on the upper level panels.

[paulythegun]

10 minutes ago, nw baltimore wx said:

Does that upper level feature rotating through Monday night/early Tuesday on the gfs have any potential?  Looks lame on the surface but not too bad on the upper level panels.

yeah looks potent on 500mb. upslope snow in the blue ridge, maybe some inverted trough snow inland in new england when the surface low actually develops (too late for us). 

[nj2va]

14 minutes ago, nw baltimore wx said:

Does that upper level feature rotating through Monday night/early Tuesday on the gfs have any potential?  Looks lame on the surface but not too bad on the upper level panels.

That upper level feature helps to enhance upslope for the mountains at the very least.  I'm not smart enough to say what it means for east of the mountains.  

[WinterWxLuvr]

For fun, go look at the 500 map for the US for Monday on the 12z run from Mon 12/11 and compare it to the same time on todays run and then tell me why one would place any hope/despair on an op run beyond about 3 days. 

[Volcanic Winter]

48 minutes ago, weatherbook said:

D.C. had a winter storm warning on Jan 3, 2022.  I measured about 8" at the Tidal Basin.  It was a classic D.C. snowstorm.

 

Beautiful shot! And a nice event, that one had a sharp cutoff just to my south where I only saw virga due to the very dry air on the north fringe, but it plastered ACY IIRC. I did better in the following event and then at the end of the month for my main snow that month. 

But 8 inches is a very nice event in an otherwise poor stretch. 

Really pulling for the megalopolis to have a good winter this year. 

[cbmclean]

1 hour ago, mattie g said:

It's not just the Pacific air itself. It's the flow that blocks the cold from getting out of Siberia (it's been f'ing cold as Dante's hell there), across Canada, and down into our neck of the woods.

We've been dealing with the flow for quite a few years now, but there's nothing to say that it's something that won't change again within another few years.

I don't really think that actual cross-polar flow (from Siberia) is super common for us or that it is the normal way we get "good cold".  My understanding is our normal cold source region is the Mackenzie river valley area.

And while agree that the Pac Puke has been more common over the last 7 years than before, we the CONUS several notable cold air outbreaks in that time.  Unfortunately it seems that most of them have been targeted at the middle of CONUS, perhaps as a result of the persistent SER over those years.  For example the great southern plains outbreak of 2021 which nearly brought the power grid to its knees.  Back in late 2017 early 2018 we had an epic cold snap that set records in terms of duration of below 32 °F.  I even hit 0 F at my house in the coastal plain which is almost unheard of.  

As usual it is a matter of degree and probability.  Pac Puke is more common than it used to be.  But it is not universal.

ETA: I mean the NC coastal plain; yes I am a spy from the SE forum.

[BristowWx]

13 minutes ago, WinterWxLuvr said:

For fun, go look at the 500 map for the US for Monday on the 12z run from Mon 12/11 and compare it to the same time on todays run and then tell me why one would place any hope/despair on an op run beyond about 3 days. 

I did that.  quite a bit different each run.  10 days until Xmas.  Anything could happen that day.  Just the 2m temps have gone from the 30s to now the 50s in 3-4 runs for 18z 25 Dec.  Who knows

[brooklynwx99]

not sure how anyone can see these kinds of setups and not get excited about the rest of the winter. loaded southern stream showing up later in the month. wait until we get a legit -NAO to establish a 50/50 ULL and you're golden

[cbmclean]

12 minutes ago, brooklynwx99 said:

not sure how anyone can see these kinds of setups and not get excited about the rest of the winter. loaded southern stream showing up later in the month. wait until we get a legit -NAO to establish a 50/50 ULL and you're golden

I'll get excited when I see the jet extension chill a bit.

[WesternFringe]

15 hours ago, clskinsfan said:

From where? This isnt January or early February where we are cold. There is no cold air on this side of the Hemisphere.And I wonder why????

No cold air?

[brooklynwx99]

5 minutes ago, cbmclean said:

I'll get excited when I see the jet extension chill a bit.

that likely happens later in the winter when wavelengths shorten

[Eskimo Joe]

26 minutes ago, brooklynwx99 said:

not sure how anyone can see these kinds of setups and not get excited about the rest of the winter. loaded southern stream showing up later in the month. wait until we get a legit -NAO to establish a 50/50 ULL and you're golden

Hey that's a better look out west. We'll establish ridge along the west coast.

[psuhoffman]

12 hours ago, Maestrobjwa said:

I actually wasn't sure it had something to do with that or not. I keep seeing folks say the artic air is "kicked" or "trapped" on the other side of the globe...Now from a layman perspective, I thought that implied there was another mechanism that did that. So you're saying all the pac air kicks the colder air to the other side of the hemisphere, or?

And from that same perspective...I also don't get how "that" problem means warm or our side of the hemisphere but still cold there. May be a dumb question, but remember...non-scientifically oriented poster here. Sometimes we need a "for dummies" explanation of these things!

First of all, the reason Siberia can get so cold is it is a much larger land mass and sheltered from any marine influence.  It is much further and the body of water that is typically upstream from them is the north Atlantic which is much smaller and cooler than the pacific.  

Second, the predominant longwave pattern or flow.  Look at this below.

I have highlighted the pac jet there.  How would any cold from Siberia be able to get here given that flow...cross polar flow is completely cut off by the pac jet blasting across N America.  Furthermore how would our source regions even be able to develop home grown cold with that flow blasting warm pacific air across the whole continent.  

It is not always cold in Siberia, well WRT normal anyways... right now it is...see below

But the flow shifts and becomes more progressive and that cold is forced out into the pacific and quickly gets obliterated as it mixes with the pacific maritime airmass...so look at next week

It's now warm in Siberia, but its still not cold here its just warm EVERYWHERE...literally the only cold in the whole hemisphere WRT normal are two small pockets over Greeenland and Alaska, both of which are under a TPV at the time.  90% of the land masses across the whole N Hem is well above normal.  

As for your other questions regarding how much of this is random v "you know what".  I can't say.  I can say the pacific pattern which is responsible for this is partially cyclical.  We are in a hostile PDO cycle.  But I can also say that there are some factors contributing to this which make it worse which have been linked to "you know what".  The expansion of the pacific basin circulation which is linked to warming has compressed the jet speeding it up making the problem worse.  The warm pools in the western Pac/IO are making this worse and also linked to warming.  And of course as the pacific warms that's going to be a problem since that is what is upstream of us.   I have no idea what percentage of this is just cyclical and what percentage might be warming but its likely some of both.  

 

 

[pazzo83]

that last temp plot is sobering af

[midatlanticweather]

6 minutes ago, psuhoffman said:

First of all, the reason Siberia can get so cold is it is a much larger land mass and sheltered from any marine influence.  It is much further and the body of water that is typically upstream from them is the north Atlantic which is much smaller and cooler than the pacific.  

Second, the predominant longwave pattern or flow.  Look at this below.

I have highlighted the pac jet there.  How would any cold from Siberia be able to get here given that flow...cross polar flow is completely cut off by the pac jet blasting across N America.  Furthermore how would our source regions even be able to develop home grown cold with that flow blasting warm pacific air across the whole continent.  

It is not always cold in Siberia, well WRT normal anyways... right now it is...see below

But the flow shifts and becomes more progressive and that cold is forced out into the pacific and quickly gets obliterated as it mixes with the pacific maritime airmass...so look at next week

It's now warm in Siberia, but its still not cold here its just warm EVERYWHERE...literally the only cold in the whole hemisphere WRT normal are two small pockets over Greeenland and Alaska, both of which are under a TPV at the time.  90% of the land masses across the whole N Hem is well above normal.  

As for your other questions regarding how much of this is random v "you know what".  I can't say.  I can say the pacific pattern which is responsible for this is partially cyclical.  We are in a hostile PDO cycle.  But I can also say that there are some factors contributing to this which make it worse which have been linked to "you know what".  The expansion of the pacific basin circulation which is linked to warming has compressed the jet speeding it up making the problem worse.  The warm pools in the western Pac/IO are making this worse and also linked to warming.  I have no idea what percentage of this is just cyclical and what percentage might be warming but its likely some of both.  

 

 

This post has me back to thinking we are seeing illusions on the long-range good looks. LOL! Need more luck than usual to get stuff to do what we need it to do these days! Thanks for the breakdown... now I will breakdown!  LOL! 

 

[clskinsfan]

28 minutes ago, WesternFringe said:

No cold air?

Its a transient 24 hour period man. I am talking about sustained cold. There is none. Run the entire 2M plot of the 12Z GFS. The 24 hour period you posted is just about it for cold through the entire run. 

[WesternFringe]

10 minutes ago, clskinsfan said:

Its a transient 24 hour period man. I am talking about sustained cold. There is none. Run the entire 2M plot of the 12Z GFS. The 24 hour period you posted is just about it for cold through the entire run. 

The ICON storm we were discussing was on 12/19.  You were saying the timing didn't matter because there was no cold to pull from, but there is cold forecasted during that timeframe.

[Ralph Wiggum]

1 hour ago, brooklynwx99 said:

 wait until we get a legit -NAO to establish a 50/50 ULL and you're golden

When those features present themselves the stj probably shuts off. Hopefully not, but that's Murphys Law for our region. I'll see myself out now....

[Ralph Wiggum]

24 minutes ago, clskinsfan said:

Its a transient 24 hour period man. I am talking about sustained cold. There is none. Run the entire 2M plot of the 12Z GFS. The 24 hour period you posted is just about it for cold through the entire run. 

You have to understand...that is  basically Nino in a nutshell. Rarely is there sustained cold. Exceptions? Yes. I made a note of this the other day...during alot of Ninos we seem to get brief windows of opportunity sandwiched between seasonal/AN stuff. Siberia being cut off is pretty common tbh.  

[psuhoffman]

3 hours ago, cbmclean said:

Actually what I think I have learned is that THE critical factor is always whichever one sucks for us at a given time.

That's because snow is an anomaly here and at our elevation and latitude it takes way more factors to be in our favor than not.  Kinda like a golf swing...takes multiple things working in unison to get it right...any one little thing can F it all up.   

[CAPE]

12z GEFS has a better track for the late month potential storm- across the southern states and up off the NC coast, more like the 0z EPS.

[brooklynwx99]

well, there’s your post-Christmas coastal signal. cold air is marginal here verbatim but still worth keeping an eye on

[brooklynwx99]

worth noting that ENS would have a really hard time picking up on transient HP that’s forced by the Canadian ridge 

[CAPE]

Just now, brooklynwx99 said:

worth noting that ENS would have a really hard time picking up on transient HP that’s forced by the Canadian ridge 

Yeah that could work, and its gonna take good timing with not much help in the NA. Any HP induced over southern Canada will be on the move.

[dallen7908]

 

White XMAS Hope lives for Canaan Valley and Mount PSU? 

[psuhoffman]

Canadian weeklies updated.  They flip the NAO negative around New Years and run the table.  Also develops a nice EPO-NAO ridge bridge.  Cue Chuck to point out the PNA is negative though.  

[Eskimo Joe]

1 minute ago, psuhoffman said:

Canadian weeklies updated.  They flip the NAO negative around New Years and run the table.  Also develops a nice EPO-NAO ridge bridge.  Cue Chuck to point out the PNA is negative though.  

Man the look on the Pacific is nice.

[stormy]

24 minutes ago, CAPE said:

12z GEFS has a better track for the late month potential storm- across the southern states and up off the NC coast, more like the 0z EPS.

Cold air aloft is very marginal at best with the 850 and the 540 line: