Winter 2012/13 wx discussion

skillsweather wrote:Well crap I wake up and winters December is canceled.. I guess we got another year like last year.. I cant believe this crap... If models still showing same warmth by January then we might as well atleast start to expect another last year cause all last year we was saying maybe it will change next week and we kept doing that and it never did change.

Fixed it for ya. Like Eric said, winter is just beginning. We are getting off to a bad start but the %'s are very low that we have a total crapfest from start to finish like last winter. Just settle in and keep model watching. Plenty of time in the future to get your weenie on.

Toot wrote:Just to give an idea on how important the December AO is for winter weather.. here are the December values from the last three winters.

December 2009 -3.413...Turned out to be a very cold winter

December 2010 -2.631 Turned out to be a very cold winter

Last December +2.221 The winter went on to torch

If the ensembles are correct this December AO value will end up averaging negative!

That's a great sample size.

snowdog wrote:Question. Why does the GFS/Euro ensemble NAO graph differ so much from the CPC ensemble graph?


Raleigh's site...

http://raleighwx.americanwx.com/models/00zlinegraphs.html

vs

CPC NAO Spaghetti plot

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

Im not sure how Alan figures his "mean" indice line graphics Snowdog...but I can tell you that most of the time they are wrong...his bar graphics for indices are usually pretty close tho. I have learned the hard way to stick to CPC for Indices from the GFS ensembles. I even have some paid indice graphics that I dont trust one minute. IMO CPC's way of measuring indices are the most accurate for the GFS ensembles.

skillsweather wrote:Well crap I wake up and winters canceled.. I guess we got another year like last year.. I cant believe this crap

jmundie wrote:
That's a great sample size.

It was just the easiest ones to remember this morning without looking into the data. I will look more into it when I get time Sally...not that I really need a bigger sample size to know what a deeply negative AO December generally means tho.

Toot wrote:Im not sure how Alan figures his "mean" indice line graphics Snowdog...but I can tell you that most of the time they are wrong...his bar graphics for indices are usually pretty close tho. I have learned the hard way to stick to CPC for Indices from the GFS ensembles. I even have some paid indice graphics that I dont trust one minute. IMO CPC's way of measuring indices are the most accurate for the GFS ensembles.

Well suck. I was using raleigh's site to get my Euro Ensemble mean tele's too. If his GFS ensembles aren't to be trusted, I guess his Euro Ensembles shouldn't be trusted either.

If the gfs ensembles are correct this December will likely feature a deeply negative Arctic Oscillation. Here is the composite temp anomaly for all winters that featured a December AO value of at least -1.90 since 1950!


The AO input data comes from here
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

It's gonna have to be pretty cold the rest of the month to make up for the positive anamolies we've had the past 4 days, and will have in the next 6.

Regardless - just taking the mean from all those years doesn't really give us an idea of what's going to happen. Generally, yes, a deeply negative AO leads to cold, but it's not a guarantee. You've got some insanely cold winters and a couple of warm ones in that sample. 05-06 wasn't great. Neither was 85-86.

jmundie wrote:It's gonna have to be pretty cold the rest of the month to make up for the positive anamolies we've had the past 4 days, and will have in the next 6.

Regardless - just taking the mean from all those years doesn't really give us an idea of what's going to happen. Generally, yes, a deeply negative AO leads to cold, but it's not a guarantee. You've got some insanely cold winters and a couple of warm ones in that sample. 05-06 wasn't great. Neither was 85-86.

Well duh!! A deeply negative AO in december is a petty rare event..thats all the years going back to 1950 and is the whole reason why im mentioining it I agree with the bolded too..I thought you knew I was just speaking in GENERAL terms of what a deeply -AO Dec normally means for the coming winter there is never a guaranteed in the long range...all we can say is what normally happens and BTW that anomaly is not really a mean its an average!!

the start of this december reminds me of the december 1984... that whole month torched and broke records... i wouldnt be suprise if we see a bunch of 70 plus days this month... with the ridge in the se in place... and the sw flow taking place... we can only hope it turns in january like it did that year... though that was a nina...

Bruce - that seems very similar to what Curt said on another forum.

Onto the topic at hand - 0z runs say next weeks system ushers in winter. Multiple synoptic snow threats on the CMC from 192 to 240

Ensembles seem to be keying in on some pretty strong NAO blocking in the extended! Fun times

Also..for those of you that have been fooled into believing that a pattern change to colder wasnt going to happen..I present you with the morning run of the GFS ensemble mean. Total pattern flip about to commence for the second half of December with most of the country going from warm to cold!

This is a very interesting video to watch. https://www.youtube.com/watch?feature=player_embedded&v=c_Y2xK7HeO0

He basically says he thinks we will be pretty neutral this winter in temps with warmer then average for most parts but several arctic outbreaks and stuff.. And above normal snowfall since we will be in the battle ground area of the trough or something like that. lol just watch video

Bring it on!!!! My wife was about to move back to Florida with these warm temperatures. Lol.
Toot, do you see any chance of flurries here in Knoxville around the 10th and 11th? I know there not the most dependable but accuweather show's that possibility, on today's run anyway......

joereb1 wrote:
Toot, do you see any chance of flurries here in Knoxville around the 10th and 11th? I know there not the most dependable but accuweather show's that possibility, on today's run anyway......

Some flurries looks like a decent possibility at this point and there is already pretty good agreement that this system will have decent strength and dynamics associated with it. It wouldnt at all surprise me to see some snow flying in wake of the LPS.. but it will likely come down to the stormtrack and how close the center tracks to our area. Certainly and interesting storm system being progged

Toot wrote:

joereb1 wrote:
Toot, do you see any chance of flurries here in Knoxville around the 10th and 11th? I know there not the most dependable but accuweather show's that possibility, on today's run anyway......

Some flurries looks like a decent possibility at this point and there is already pretty good agreement that this system will have decent strength and dynamics associated with it. It wouldnt at all surprise me to see some snow flying in wake of the LPS.. but it will likely come down to the stormtrack and how close the center tracks to our area. Certainly and interesting storm system being progged

Yeah - GFS is insinuating a decent fetch off the lakes as it rapidly deepens the low through the northeast

Crazy uncle Nogaps develops a secondary wave of low pressure along the strong cold front resulting in a snowstram



Meanwhile the 18z GFS has developed a really strong NAO block in la la land The one thing I have noticed in all guidance is the subtropical branch of the jetstream definately trying to wake up.

jmundie wrote:Bruce - that seems very similar to what Curt said on another forum.

Onto the topic at hand - 0z runs say next weeks system ushers in winter. Multiple synoptic snow threats on the CMC from 192 to 240

mundie... o how i would love to see that repeated again buddy.

Hmmm....

If the euro is holding energy back there (which it appears to be doing) then we may have some excitement next week.

Some of the ensembles are starting to look interesting also Mundie!



Meanwhile.. the system that thought about severe for a while looks like a strung out dope fiend!

Below is the latest run of the GFS ensemble mean showing the change from warm to colder. I think the GFS ensemble package has been more consistent with the NH pattern while the euro and its ensembles continue to waffle back and forth!

The Ensembles are definitely more consistent than either the GFS op or the Euro op. However, what worries me, is that the unrelenting Pacific just refuses to change. I think the models are playing catch up to just how powerful it is. They continue to advertise a change to colder weather, only to be rushing the change to quickly. I think it will eventually come, but something in the Pacific is going to have to give, or we will be waiting till next year imo before we can hope for a more wintry look.

In a year where the Pacific was not quite as bad, I think the pattern change would have already occurred and we'd be like Europe right now. Cold and stormy. The -NAO can only do so much. It's tempting to say, well, we're paying for the awesome snowy winters of 09-10 and 10-11 with one absolute looser of a winter in 11-12, and one faker, that is difficult to get going i.e. this one, but I don't think that's a fair assessment. I honestly believe the current winter will get going, but it's going to take it's own bitter sweet time doing it. Maybe late December, but I imagine January is going to be the time to watch. I've seen the models rush the change for too many years now, including with no exception this year. If I'm wrong, then we can all celebrate in snow before Christmas, and I'll gladly admit defeat, but I'm just not hopeful, like many for anything until after Christmas.

GFS ensembles locking in on a nice snow threat in the 240-276 timeframe. Almost all members show this storm. Some are slightly too warm.

Check it

I hope we can sneak a threat in here. I'm still not seeing anything good pattern wise on the long range tele's from the 12z Euro and GFS ensemble mean. still shows a +EPO/-PNA in the long range. AO is also going back near positive.

I would also like to point out that, much like last winter, when the AO went deeply negative we mostly missed it.

Jed33 wrote:The Ensembles are definitely more consistent than either the GFS op or the Euro op. However, what worries me, is that the unrelenting Pacific just refuses to change.

Im not worried at all about the pacific with such a negative Arctic Oscillation as the NAO and eventually the EPO should follow into negative territory

snowdog wrote:I hope we can sneak a threat in here. I'm still not seeing anything good pattern wise on the long range tele's from the 12z Euro and GFS ensemble mean. still shows a +EPO/-PNA in the long range. AO is also going back near positive.

I would also like to point out that, much like last winter, when the AO went deeply negative we mostly missed it.

The AO is not shown to go positive.. in fact its shown to keep going deeply negative in the near term...not sure where you are getting that at. I seriously doubt we see the AO go positive at all this winter. The pacific is also much improved..there is now a ridge where there was once a AK vortex. I know there is a bunch of people out there saying "We are stuck in this warm pattern...Blah Blah Blah" but the pattern has already changed greatly from what it once was. The NAO is fixing to go negative and if the Atlantic block retrogrades westward there will be a snow threat in the eastern US around the 16th-20th!

Also.. the AO was only negative for a brief period of time during the month of JAN last year. Otherwise it was raging positive...a complete opposite of this year! Im sick of people comparing this winter to last when the NH 500mb pattern is clearly much different! Of course..it seems that nobody is going to admit to this until they see below zero temperatures here in the southeastern US.. when climo clearly argues that we wont start seeing much colder until January


A pattern change driven by the AO takes time.. as it works its way down from the higher latitudes into the mid latitudes! I fully believe that the turn to colder has already began and by Christmas we will be in a much colder regime. If im wrong I will be the first to admit it