December Med/Long Range Disco

[Bob Chill]

January will bring all the HECS to the yard.

 

White xmas, boxing day, nye, and then it really gets going after that. 

[AvantHiatus]

Not sure if anyone has noticed this but the NPAC has cooled decently. Looks like we won't see a +PDO/+EPO combo on the same level as 2013 or what not. This can only mean a moderated winter unless the NAO flips hard into deep negative departures.

 

I honestly see a 'meh' winter with elevated areas favored for snow and will stop posting if there is a HECS in January. 2013-2014 was not like 2009-2010 as most realize. It was more of a case of reaching the same result thru two different pathways. 

[dallen7908]

Honest Question: Are these 360 hour ensemble means more or less accurate than climatology? At that time range, would errors in model climatology dwarf any predictive skill?

 

If this pattern verifies at hour 420 instead, does this count as a useful forecast? 

[WinterWxLuvr]

Not sure if anyone has noticed this but the NPAC has cooled decently. Looks like we won't see a +PDO/+EPO combo on the same level as 2013 or what not. This can only mean a moderated winter unless the NAO flips hard into deep negative departures.

I honestly see a 'meh' winter with elevated areas favored for snow and will stop posting if there is a HECS in January. 2013-2014 was not like 2009-2010 as most realize. It was more of a case of reaching the same result thru two different pathways.

Lame.

[CAPE]

Not sure if anyone has noticed this but the NPAC has cooled decently. Looks like we won't see a +PDO/+EPO combo on the same level as 2013 or what not. This can only mean a moderated winter unless the NAO flips hard into deep negative departures.

 

I honestly see a 'meh' winter with elevated areas favored for snow and will stop posting if there is a HECS in January. 2013-2014 was not like 2009-2010 as most realize. It was more of a case of reaching the same result thru two different pathways. 

How about now?    

[Fozz]

You better be right. 

 

January 2000 repeat next month??

[PhineasC]

Not sure if anyone has noticed this but the NPAC has cooled decently. Looks like we won't see a +PDO/+EPO combo on the same level as 2013 or what not. This can only mean a moderated winter unless the NAO flips hard into deep negative departures.

 

I honestly see a 'meh' winter with elevated areas favored for snow and will stop posting if there is a HECS in January. 2013-2014 was not like 2009-2010 as most realize. It was more of a case of reaching the same result thru two different pathways. 

Any chance you could do a dry-run of the "stop posting" thing so we can evaluate your offer?

[T. August]

Any chance you could do a dry-run of the "stop posting" thing so we can evaluate your offer?

[hosj III]

Not sure if anyone has noticed this but the NPAC has cooled decently. Looks like we won't see a +PDO/+EPO combo on the same level as 2013 or what not. This can only mean a moderated winter unless the NAO flips hard into deep negative departures.

 

I honestly see a 'meh' winter with elevated areas favored for snow and will stop posting if there is a HECS in January. 2013-2014 was not like 2009-2010 as most realize. It was more of a case of reaching the same result thru two different pathways. 

 

um... the PDO is much more positive now than in Dec 2013. The SSTA profile is about as good as it can get. 

 

2013-2014 was quick hitting events in progressive flow with a -EPO supplying the cold... 2009-2010 was a big amped up flow with a crazy -NAO and a raging STJ. They weren't similar at all. 51" last winter is not the same animal as the close to 85" I got in 2009-2010, most of which fell in a 10 day period. The people who say 2013-2014 was better than 2009-2010 for any reason have foggy memories.

 

Not sure what your point is.

[StudentOfClimatology]

Not sure if anyone has noticed this but the NPAC has cooled decently. Looks like we won't see a +PDO/+EPO combo on the same level as 2013 or what not. This can only mean a moderated winter unless the NAO flips hard into deep negative departures.

Are you legit right now? In what universe was 2013-14 a +EPO winter? Also, cooling in the North-Central Pacific is a +PDO signature..2013-14 was more of a neutral PDO.

What makes you think the +PDO we have now will lead to a "moderated winter"? There's no logic to that..

[andyhb]

That guy really needs to review his teleconnections/indices.

[Ji]

Euro has a near miss big snow day 8-10

[mappy]

Euro has a near miss big snow day 8-10

 

12/19 repeat

[aldie 22]

Euro has a near miss big snow day 8-10

Gfs has a nice storm around the 23rd

[Bob Chill]

All ensembles locking into to a pretty decent snow pattern as we approach Christmas. Fantasy threats will likely be plentiful this week.

[WxUSAF]

All ensembles locking into to a pretty decent snow pattern as we approach Christmas. Fantasy threats will likely be plentiful this week.

Pattern looks active for sure, so I think we'll get our chances.  I think better chance for snow probably comes between Christmas and New Year's given the temperatures, but I think our chances for a white Christmas are at least at climo if not maybe a tick above.  

[yoda]

Pattern looks active for sure, so I think we'll get our chances.  I think better chance for snow probably comes between Christmas and New Year's given the temperatures, but I think our chances for a white Christmas are at least at climo if not maybe a tick above.  

 

6z GFS OP has two nice fantasy chances with a juicy southern stream it appears and the H located in Quebec in the right place if we were to take it exact... 12/19 and 12/23 are the dates... I agree with Bob and you that LR GFS is likely going to be showing decent fantasy storms in the Day 11-15 range and hopefully we can get those threats under the 10 day.. h5 pattern is decent too

[HM]

A series of southern lows starts next week and will begin our threats for snowfall, despite the lack of a true -NAO/Arctic Air. Marginal but sufficient air and a juicy southern low can deliver with a proper track. There are clearly 2 threats in the next 2 weeks, one of which is pretty close to xmas.

The other good news is that it is looking increasingly likely that a SSW will get going late Dec into early Jan. In some analogs, it took until second week of January for the AO to flip...then there are some that took even longer. The toughest part is trying to figure out when the AO flips. Either way, it's definitely the beginning of the eventual flip that you're seeing at the end of the computer models.

[HM]

A series of southern lows starts next week and will begin our threats for snowfall, despite the lack of a true -NAO/Arctic Air. Marginal but sufficient air and a juicy southern low can deliver with a proper track. There are clearly 2 threats in the next 2 weeks, one of which is pretty close to xmas.

The other good news is that it is looking increasingly likely that a SSW will get going late Dec into early Jan. In some analogs, it took until second week of January for the AO to flip...then there are some that took even longer. The toughest part is trying to figure out when the AO flips. Either way, it's definitely the beginning of the eventual flip that you're seeing at the end of the computer models.

On that last point, some of the higher snow cover years got going just before the New Year with Arctic Air. Cohen's work outlines this well with the typical progression. Typically, wave 1, displacement SSWs are a more slowly evolving type of AO flip...same can be said for Nino winters which also tend to downwell -u wind mid to late January. Sooooo....???

[snowfan]

Damn.....so everyone should go out and buy 36" snow blowers.

 

In all seriousness, thank you for the pro look at things. It's really great to have folks like you and Wes hanging around here.

On that last point, some of the higher snow cover years got going just before the New Year with Arctic Air. Cohen's work outlines this well with the typical progression. Typically, wave 1, displacement SSWs are a more slowly evolving type of AO flip...same can be said for Nino winters which also tend to downwell -u wind mid to late January. Sooooo....???

[HM]

Damn.....so everyone should go out and buy 36" snow blowers.

 

In all seriousness, thank you for the pro look at things. It's really great to have folks like you and Wes hanging around here.

It's no problem at all.

How does the Mid Atlantic do snow usually? With an active southern stream and that's what we've got! All this nonsense all warm season long about "is El Nino coming" ....meanwhile...CA rainfall, historic E PAC tropical season and a classic Nino Dec pattern.... Keep monitoring that SOI and 3.4 number....lol

[Bob Chill]

A series of southern lows starts next week and will begin our threats for snowfall, despite the lack of a true -NAO/Arctic Air. Marginal but sufficient air and a juicy southern low can deliver with a proper track. There are clearly 2 threats in the next 2 weeks, one of which is pretty close to xmas.

The other good news is that it is looking increasingly likely that a SSW will get going late Dec into early Jan. In some analogs, it took until second week of January for the AO to flip...then there are some that took even longer. The toughest part is trying to figure out when the AO flips. Either way, it's definitely the beginning of the eventual flip that you're seeing at the end of the computer models.

In my simplistic view, global ensembles are keying on the sw entering the west coast around the 19-20th or so being the one that pops the western ridge in it's wake. I think we'll struggle with temps with any storm before that one makes its trek. Beyond that is starting to look pretty tasty on the means. -AO signal is growing stronger as we move forward in time. Not perfect because of the nao being stubborn but I feel pretty good about the last week of the month having some chances. The change to favorable ridging in the west is staying put in time and not washing out. Still quite a few days to go before it become likely/certain. Always appreciate your thoughts here.

[mitchnick]

A series of southern lows starts next week and will begin our threats for snowfall, despite the lack of a true -NAO/Arctic Air. Marginal but sufficient air and a juicy southern low can deliver with a proper track. There are clearly 2 threats in the next 2 weeks, one of which is pretty close to xmas.

The other good news is that it is looking increasingly likely that a SSW will get going late Dec into early Jan. In some analogs, it took until second week of January for the AO to flip...then there are some that took even longer. The toughest part is trying to figure out when the AO flips. Either way, it's definitely the beginning of the eventual flip that you're seeing at the end of the computer models.

 

 

On that last point, some of the higher snow cover years got going just before the New Year with Arctic Air. Cohen's work outlines this well with the typical progression. Typically, wave 1, displacement SSWs are a more slowly evolving type of AO flip...same can be said for Nino winters which also tend to downwell -u wind mid to late January. Sooooo....???

I was wondering, can I get a few minutes alone everyone?

 

Dat' sum gud shiat there Mr. HM!

[usedtobe]

It's no problem at all.

How does the Mid Atlantic do snow usually? With an active southern stream and that's what we've got! All this nonsense all warm season long about "is El Nino coming" ....meanwhile...CA rainfall, historic E PAC tropical season and a classic Nino Dec pattern.... Keep monitoring that SOI and 3.4 number....lol

Right now I'd still place the probability of getting snow xmas week pretty much at climo. I had been leaning a little above so I could still change my tune by Thursday's outlook but right now am not ready to pull the above normal for xmas lever.  The southern storm track is a big plus but the NAO and AO  are still likely to be positive or for the latter maybe neutral at best while the former is still gonna be positive.  We have to hope there is enough ridging over the west to sneak enough cold air into the area while also having the pressure stay high over the great lakes so any high pressure are doesn't get pushed off the coast.  That's always a worry with a positive nao.  Like you, I still think we have a good January and think the pattern looks to be improving some towards xmas but.....I tend to be conservative with pattern changes. 

[HM]

Right now I'd still place the probability of getting snow xmas week pretty much at climo. I had been leaning a little above so I could still change my tune by Thursday's outlook but right now am not ready to pull the above normal for xmas lever.  The southern storm track is a big plus but the NAO and AO  are still likely to be positive or for the latter maybe neutral at best while the former is still gonna be positive.  We have to hope there is enough ridging over the west to sneak enough cold air into the area while also having the pressure stay high over the great lakes so any high pressure are doesn't get pushed off the coast.  That's always a worry with a positive nao.  Like you, I still think we have a good January and think the pattern looks to be improving some towards xmas but.....I tend to be conservative with pattern changes.

Sounds good. Basically, the background PDO-ENSO state favors a climo progression, for a change. We've had a negative state for so long that usually there is no sign of a southern stream at this point or PNA. This background state allows each passing week to do what it is supposed to do in the Mid Atlantic and slowly increase probability of snow. That's really all you can ask for at this stage.

As far as anything significant, until the NAO/AO comes around that will obviously be low chances. But a parade of southern stream lows is definitely a welcomed sight!

[HM]

In my simplistic view, global ensembles are keying on the sw entering the west coast around the 19-20th or so being the one that pops the western ridge in it's wake. I think we'll struggle with temps with any storm before that one makes its trek. Beyond that is starting to look pretty tasty on the means. -AO signal is growing stronger as we move forward in time. Not perfect because of the nao being stubborn but I feel pretty good about the last week of the month having some chances. The change to favorable ridging in the west is staying put in time and not washing out. Still quite a few days to go before it become likely/certain. Always appreciate your thoughts here.

This background state allows the Mid Atlantic to follow snowfall climo, which is a good thing for a change. We've seen in past winters, at this stage a polar vortex strengthening and no southern stream...basically below normal climo chances for snow into Jan-Feb. With split flow/PNA, Mid Atlantic is at worst climo.

[yoda]

I will take Day 11 on the 12z GFS to go please

 

Decent h5 and nice track

 

Looks like Dec 19 to Dec 23 is starting to become a strong signal on the OP for potential snow for us

[Heisy]

Right on cue, check out the 186hr GFS, looks like a solid cold blast with a nice HP building in behind it, but look at the STJ and the shortwave in the SW, could be a good setup.

[WxUSAF]

12z gfs @ hr276 looks good

 

 

Christmas day mecs on the gfs looks pretty nice

Even though I know you're trolling and I've seen the maps, I get all excited about this and then get frustrated  

 

Anyway, yeah, it's an active pattern and will offer some chances.  Next Tuesday-Wednesday bears watching with a northern and southern stream vort close to phasing.  0z Euro and 12z GFS both miss the phase, but not by much.  

   

Next Thursday-Friday could be sneaky cold in the midst of this mega-torch we're seeing.  It's that cold push and the timing of it dictated by the Tuesday-Wednesday storm that would set up the environment for the 21st.     

 

But damn that constant push of southern stream s/w's undercutting a western ridge every 2-3 days is enticing.  

[Bob Chill]

Trolling mostly but it's no coincidence that the ops are starting to throw this stuff out at the same time ensembles are locking into a significantly better pattern for snow chances. Setup and timing details cannot be resolved with any skill but some ingredients are showing their faces. We should count how many fantasy storms each op spits out over the next week. 6+12z gefs is 4 so far.