December Pattern Disco- 2013

[Baroclinic Zone]

It's entirely possible as stated. It looks like a couple of messy events to start the month as the PNA drops and forces lows over us. Looks like it could be a messy event over the interior and NNE but it could also be a little more west. Volatility.

We'll run the risk of messy systems (cutters, inland runners) unless we get some solid blocking in place.  Timing and location will be critical for those seeking a more wintry appeal.

[CoastalWx]

The overall look beyond is definitely a SWFE look which we can do fine in without blocking so long as dateline ridging is poleward.

[Baroclinic Zone]

The overall look beyond is definitely a SWFE look which we can do fine in without blocking so long as dateline ridging is poleward.

Well, yeah, you wouldn't call that a classic blocking pattern but if you can get some solid confluence across there it can act as a block, no?

 

Dumb question that's probably been answered but is the E-Wall day 8-10 mean from just the OP runs or does that include the Ensm?

[toronto blizzard]

The overall look beyond is definitely a SWFE look which we can do fine in without blocking so long as dateline ridging is poleward.

Sounds good. I remember December 2008 had a torching cutter before those SWFE's started the 2nd half of the month. Have to be patient.

[ORH_wxman]

Well, yeah, you wouldn't call that a classic blocking pattern but if you can get some solid confluence across there it can act as a block, no?

 

Dumb question that's probably been answered but is the E-Wall day 8-10 mean from just the OP runs or does that include the Ensm?

 

Most of our SWFE patterns have no blocking...only up in the EPO region. But the Atlantic was often a raging +NAO in Dec 2007 and 2008 when we were getting SWFEs. Its easier to get them deeper into December when all the wavelengths lengthen a bit and the cold air sinks further south. Its definitely a favorable pattern for SWFEs on the Euro ensemble mean out into December.

 

Whether we get them or we get warmer cutters is entirely dependent on nuances that aren't predictable on this timescale.

[CoastalWx]

That is some serious cold coming south in the 11-15 day. Pieces of this will try to break east and I don't see how it won't be stormy at times as this occurs. It might be fun times if we can get it to cooperate.

[Clinch Leatherwood]

Most of our SWFE patterns have no blocking...only up in the EPO region. But the Atlantic was often a raging +NAO in Dec 2007 and 2008 when we were getting SWFEs. Its easier to get them deeper into December when all the wavelengths lengthen a bit and the cold air sinks further south. Its definitely a favorable pattern for SWFEs on the Euro ensemble mean out into December.

 

Whether we get them or we get warmer cutters is entirely dependent on nuances that aren't predictable on this timescale.

 

 

Exactly and we may well see a waivering pattern where one event is able to stay more wintry..the next ends up a cutter.  At least cold is punching down randomly and there's potential.   That's really all we can ask for so early in the year anyway.

[ORH_wxman]

Dear God..what happened to our wintry event in early Dec. Euro looks horrific. Please do not let that happen and hope the ensembles were colder

 

 

dude, its like 8-9 days out? Why are you getting emotionally invested in events that are 8 days out? It could easily be snow/ice for a time with that high to the north...it could also easily be a 50F cutter...there is no guarantee we get a bunch of snow and ice events the first week of December. It is still early.

 

C'mon man.

[CoastalWx]

You can see the evolution for the first week of December. Another mega dateline ridge forms and a piece of the PV in Siberia breaks off and heads through AK and points SE. As a result, heights rise in the east and open the door up for messy and/or milder solutions. It's a very -PNA pattern in early December so it happens.  The cold is sort of held at bay with some SE ridging forming. There is the chance of the cold moving east if we have some height rises out west or near Greenland, but for now...don't be shocked at a changeable and even delayed pattern. If I had to guess....I think we could be set up well towards mid month so long as the ridging near the dateline/AK still holds firm. This is jus the overall look...you can always sneak in something not seen 2 weeks out.

[ORH_wxman]

You can see the evolution for the first week of December. Another mega dateline ridge forms and a piece of the PV in Siberia breaks off and heads through AK and points SE. As a result, heights rise in the east and open the door up for messy and/or milder solutions. It's a very -PNA pattern in early December so it happens.  The cold is sort of held at bay with some SE ridging forming. There is the chance of the cold moving east if we have some height rises out west or near Greenland, but for now...don't be shocked at a changeable and even delayed pattern. If I had to guess....I think we could be set up well towards mid month so long as the ridging near the dateline/AK still holds firm. This is jus the overall look...you can always sneak in something not seen 2 weeks out.

 

 

That is really cold stuff out in the plains and N rockies...if we can get pieces of that oozing in over the top, that would be pretty ideal for some SWFEs. I am liking that we are avoiding any ugly vortex over the EPO/WPO region. We'll cash in at some point going into December if that remains the case.

 

But without a solid -NAO, folks should be prepared for some warm intervals too including cutters.

 

 

One of the funny things I was thinking of last night was how Dec 2008 seems to be remembered for cold/snow here...but people forget how warm it was at times that month with a couple cutters mixed in. We had like 7 days hit 50F that month in ORH...but also had 31 inches of snow and a historic ice storm...that's what you play with when you have EPO ridging with a big -PNA and a +NAO.

[N. OF PIKE]

Overall outlook morphed into dog crap for first third/ half of dec. Just calling like it is. Cutters and "messy" (rain) storms while i would put odds lower for winter storms in that period. There after, who knows. Cold is in the west w -PNA and we should prob not get hopes up, bottom like,this period look'd better a few days ago. Ya we could get lucky, but meh.

[Cold Miser]

No big deal, pick.  There's always January to look forward to.

[CoastalWx]

I disagree. We said there may be a relaxation and this is what's occurring. We also said that sometimes you play with fire when you have a -PNA. Sometimes when you approach the time period in question the signal gets stronger, but don't say we didn't warn you.

Like Will said, the rewards are huge in a pattern like this. I still like the overall look getting beyond week1 with th chances of SWFE. However we still may be cutter prone. I see signs the MJO may want to tickle warmer phases before circulating around again. Dec 2008 had warmth, cutters, and 30" of snow as stated by Darth Vader.

[ORH_wxman]

Overall outlook morphed into dog crap for first third/ half of dec. Just calling like it is. Cutters and "messy" (rain) storms while i would put odds lower for winter storms in that period. There after, who knows. Cold is in the west w -PNA and we should prob not get hopes up, bottom like,this period look'd better a few days ago. Ya we could get lucky, but meh.

 

 

Early December is ugly for the CP...just the way it is. You always have to hope to get lucky.

 

The Dec 2-5 "relaxation" has been mentioned several times. If people were expecting huge snowstorms with that rhetoric, then there's probably some communication breakdown. Some years you have no chance in the first 10 days of December...that is likely not the case this year. There will probably be chances. Chances doesn't equal snowstorms...if they did then we wouldn't use the word chance.

[CoastalWx]

Early December is ugly for the CP...just the way it is. You always have to hope to get lucky.

The Dec 2-5 "relaxation" has been mentioned several times. If people were expecting huge snowstorms with that rhetoric, then there's probably some communication breakdown. Some years you have no chance in the first 10 days of December...that is likely not the case this year. There will probably be chances. Chances doesn't equal snowstorms...if they did then we wouldn't use the word chance.

I even remember stating the caveats and ending a post with" I don't want to hear it if there is bare ground after the first week of December."

[powderfreak]

Early December is ugly for the CP...just the way it is. You always have to hope to get lucky.

The Dec 2-5 "relaxation" has been mentioned several times. If people were expecting huge snowstorms with that rhetoric, then there's probably some communication breakdown. Some years you have no chance in the first 10 days of December...that is likely not the case this year. There will probably be chances. Chances doesn't equal snowstorms...if they did then we wouldn't use the word chance.

In the end (as you know), it all comes down to snow. Cold gets equated with snow and you can have a beautiful pattern that doesn't produce, and it's a bust. You can then have an atrocious pattern that somehow brings a big widespread snow and it will be referred to more positively than the awesome pattern that didn't produce.

[CoastalWx]

So there are three things most of us do when we break down a pattern. Explain the good, bad, and the way we are leaning. The good and bad have been discussed. I'm leaning an overall tough look for the CP for week 1 although one or two messy storms could potentially start as snow. Interior may have more mixed deals, especially early next week. I do feel chances for all of us our better after week 1. Not great, but better. Details this far out are pointless.

[ORH_wxman]

I even remember stating the caveats and ending a post with" I don't want to hear it if there is bare ground after the first week of December."

 

 

It's why I like to avoid "hyping" a pattern...it creates a set of expectations that can sometimes get out of control if not worded carefully.

 

 

Back to the upcoming pattern...I see potential for a small event on Dec 1 with that energy dampening out as it comes east and the very cold high to the north. Almost onshore flow ocean enhanced too.

 

 

After that, I think the trough digging in the west wuill warm us up for the Dec 3-5 period with a good chance at a cutter in that time frame (but some hint of a high in Quebec too, so who knows). After that, it looks like we could settle in to deeper cold for a time, but it's still not certain. The -PNA tendency always makes it risky.

[ORH_wxman]

In the end (as you know), it all comes down to snow. Cold gets equated with snow and you can have a beautiful pattern that doesn't produce, and it's a bust. You can then have an atrocious pattern that somehow brings a big widespread snow and it will be referred to more positively than the awesome pattern that didn't produce.

 

 

December 2007 was an example of a very risky pattern (even more than Dec 2008) that worked out almost perfect. That month easily could have been almost snowless if some very minor changes were present (this is evident by looking at snow just to the south like near NYC). Instead, BOS got 27.7" for it's 2nd snowiest December on record.

 

It is hard to gauge fast moving flows where large downstream blocking is not present. It makes forecasting events very difficult. If the source region to our north in Canada is cold, then you'll very often have chances in these patterns, but those chances come with a risk...and of course that risk being an amped shortwave that wants to tilt negative too soon...and there is absolutely nothing to stop it, so you get a torching cutter.

[mitchnick]

So there are three things most of us do when we break down a pattern. Explain the good, bad, and the way we are leaning. The good and bad have been discussed. I'm leaning an overall tough look for the CP for week 1 although one or two messy storms could potentially start as snow. Interior may have more mixed deals, especially early next week. I do feel chances for all of us our better after week 1. Not great, but better. Details this far out are pointless.

in fairness to many of the posters in your area, you guys have had a great run the last few years, save 11/12, and the best case scenario has usually worked out so most snow weenies come to expect it to always work out regardless of the caveats

bad memories are buried so only the hits come to mind and potential misses are disregarded

pretty typical human nature, which is then exacerbated by the OCD of typical snow weeenies

[weathafella]

You can even see I today's op in clown range that it wouldn't take a lot for that boundary to be south of us. Patience friends. This early deep cold may have warped the thinking of some.

[Clinch Leatherwood]

December 2007 was an example of a very risky pattern (even more than Dec 2008) that worked out almost perfect. That month easily could have been almost snowless if some very minor changes were present (this is evident by looking at snow just to the south like near NYC). Instead, BOS got 27.7" for it's 2nd snowiest December on record.

 

It is hard to gauge fast moving flows where large downstream blocking is not present. It makes forecasting events very difficult. If the source region to our north in Canada is cold, then you'll very often have chances in these patterns, but those chances come with a risk...and of course that risk being an amped shortwave that wants to tilt negative too soon...and there is absolutely nothing to stop it, so you get a torching cutter.

 

I'm surprised by the reaction and overreaction to the upcoming weather.

 

The "deep winter" dialog perpetuates the idea this was going to be a bell to bell winter which is just not in the cards.    As you've noted we lack really any upstream blocking and as a result we run the risk of cutters until that changes.  You guys are far better at determining whether or not that may occur last year notwithstanding.

In the meantime it's not 70 degrees in November and December which is a major improvement over previous years and we're shedding SSTs which are now 2-3 F below the last two years at this time. 

[CoastalWx]

It's why I like to avoid "hyping" a pattern...it creates a set of expectations that can sometimes get out of control if not worded carefully.

Back to the upcoming pattern...I see potential for a small event on Dec 1 with that energy dampening out as it comes east and the very cold high to the north. Almost onshore flow ocean enhanced too.

After that, I think the trough digging in the west wuill warm us up for the Dec 3-5 period with a good chance at a cutter in that time frame (but some hint of a high in Quebec too, so who knows). After that, it looks like we could settle in to deeper cold for a time, but it's still not certain. The -PNA tendency always makes it risky.

12/1 has been hinted at for a few days now. Very cold to start out and it does have a mini OE look too. Almost looks like OE overrunning if you will, as the coastal front pushes west.

[Tropopause_Fold]

12/1 has been hinted at for a few days now. Very cold to start out and it does have a mini OE look too. Almost looks like OE overrunning if you will, as the coastal front pushes west.

yeah i'm wondering if we can sneak a little light accumulation out of that over some of the area even beginning Sat. Maybe one of those deals where OE starts to slowly move west 

[ORH_wxman]

12/1 has been hinted at for a few days now. Very cold to start out and it does have a mini OE look too. Almost looks like OE overrunning if you will, as the coastal front pushes west.

 

 

Remember the event last year on the same exact date? It was that CAD overrunning event...we got like a little burst of snow in the morning for about an inch...and then we CAD'd with freezing drizzle for the rest of the day. That's when the NAM began its problems last year with CAD events...it had like 38F for a high and we were in the upper 20s to around 30F all day.

 

http://www.meteo.psu.edu/~fxg1/NARR/2012/us1201.php

[N. OF PIKE]

I think i was in salem, ma that nite and it never got above 32 , even a mile from shore, ground stay'd white.

[CoastalWx]

yeah i'm wondering if we can sneak a little light accumulation out of that over some of the area even beginning Sat. Maybe one of those deals where OE starts to slowly move west 

 

 

Remember the event last year on the same exact date? It was that CAD overrunning event...we got like a little burst of snow in the morning for about an inch...and then we CAD'd with freezing drizzle for the rest of the day. That's when the NAM began its problems last year with CAD events...it had like 38F for a high and we were in the upper 20s to around 30F all day.

 

http://www.meteo.psu.edu/~fxg1/NARR/2012/us1201.php

 

Oh yeah I do remember that. Wow, not to far off as depicted. Phil, I could also see that too...almost like a mini OE band that pushes west. 

[CoastalWx]

Fri-Sun look pretty darn chilly once again. 

[weathafella]

The new normal is a little snow event on my bday.

[CoastalWx]

The long range euro op and GGEM ensembles actually develop a cstl with very marginal air near day 9. Not exactly the models you want in your camp at the time...but fwiw.