Winter 2014-2015 Pattern Discussion Thread I

[Eastatlwx]

Looks like nice blocking over Alaska day 11-16 on GEFS control run - 500mb, 540 thickness line above all of Alaska.

[Eastatlwx]

Very anomalous ridge I should say, 300 GPM

[RONALD B]

What does the weeklies look like on the 21th / system track ?

[tnweathernut]

[franklin NCwx]

What does the weeklies look like on the 21th / system track ?

weeklies are just an extension of the euro ensembles,from 0z of last night. Someone already posted the 12z ensembles from earlier and they are split between a cutter and a miller a.

[GaWx]

 I just noticed that the 12Z EPS and 12z CMC ens mean both have a solid -AO starting ~12/21 as well as a new -NAO starting ~12/25. The overall upper latitude blocking looks textbook great by Christmas. If that verifies, look out below for at least cold.

[Jon]

What does the weeklies look like on the 21th / system track ?

the control mslp anomaly starts over eastern TX, tracks over western TN and tracks east to central NC, bombs out under mass, odd little track, would mean rain for most in the SE I'd imagine. With that said, mean looks good for NC and the SE in general for 240hrs out.

[packbacker]

 I just noticed that the 12Z EPS and 12z CMC ens mean both have a solid -AO starting ~12/21 as well as a new -NAO starting ~12/25. The overall upper latitude blocking looks textbook great by Christmas. If that verifies, look out below for at least cold.

 

That's good news, thanks for the updates!

[Solak]

 

WeatherBELL Analytics LLC added 5 new photos.

2 mins ·

Our confidence in cold winter grows. GFS ensembles, EC weeklies, JAMSTEC, JMA, CPC constucted analogs fitting our cold analogs. December featured transitory warmth in numerous analog years. if you read our posts and see our videos we explain why this break after November was not unexpected and why January/February will be brutal with lots of snow and cold. We will likely see snows and cold the last week of the month.11 days into December, warmth mainly southwest and southeast. Compare to Decembers 2002 and 2003, two of our analogs for the whole month.

[Jon]

 I just noticed that the 12Z EPS and 12z CMC ens mean both have a solid -AO starting ~12/21 as well as a new -NAO starting ~12/25. The overall upper latitude blocking looks textbook great by Christmas. If that verifies, look out below for at least cold.

Yeah one thing I feel is certain for the LR is the -AO, I mentioned it earlier today near noon most models continue to have it and have not let up for most of the month. http://www.americanwx.com/bb/index.php/topic/44856-winter-2014-2015-pattern-discussion-thread-i/page-50#entry3184299 Same with the +PNA the only question is the -NAO and when that will start, I'm guessing early January just because it keeps going neutral even on the current 18z GEFS, barely goes negative on 12z CMC ENS, was positive on 00z CMC ENS so that's a plus at least...same with the EPS it's barely there run to run. We'll see.

[broken024]

Can someone explain what +/- nao/ao/pna mean?

[Jon]

Can someone explain what +/- nao/ao/pna mean?

AO/NAO: http://nc-climate.ncsu.edu/climate/patterns/NAO.html

PNA: http://www.nc-climate.ncsu.edu/climate/patterns/PNA.html

Extra stuff including Jet Stream and QBO I think: http://nc-climate.ncsu.edu/climateblog?id=106

[Cold Rain]

Can someone explain what +/- nao/ao/pna mean?

Officially, the +PNA/-AO/-NAO regime is a favorable pattern for east coast cold and winter storms, with an upper level ridge out west, blocking over the pole and ridging in and around Greenland and eastern Canada, allowing for both cold to be transported south and a suppressed storm track. It is the best of all winter patterns and generally remains two to three weeks away at all times.

[broken024]

Thanks

[packbacker]

Yeah one thing I feel is certain for the LR is the -AO, I mentioned it earlier today near noon most models continue to have it and have not let up for most of the month. http://www.americanwx.com/bb/index.php/topic/44856-winter-2014-2015-pattern-discussion-thread-i/page-50#entry3184299 Same with the +PNA the only question is the -NAO and when that will start, I'm guessing early January just because it keeps going neutral even on the current 18z GEFS, barely goes negative on 12z CMC ENS, was positive on 00z CMC ENS so that's a plus at least...same with the EPS it's barely there run to run. We'll see.

The -AO should be a slam dunk with the record SCE/SAI and OPI. Just a matter of time. The NAO hopefully will come as that really helps us.

[Jon]

Officially, the +PNA/-AO/-NAO regime is a favorable pattern for east coast cold and winter storms, with an upper level ridge out west, blocking over the pole and ridging in and around Greenland and eastern Canada, allowing for both cold to be transported south and a suppressed storm track. It is the best of all winter patterns and generally remains two to three weeks away at all times.

[SnowGoose69]

As a whole the AO is way more important, a -NAO only guarantees you cold if the pacific and AO is cooperating, if neither or only one is, the -NAO may only serve to dampen what may otherwise be a blowtorch. The AO of course usually goes in tandem with the NAO but not always, the winters of 93-94 and 13-14 both saw a pattern in which the AO and NAO can easily be in opposite phases

[broken024]

Cool. So it might snow in the next few months.

[Jon]

Cool. So it might snow in the next few months.

Even if we get that pattern sometimes it still doesn't work out...it's more like upping our odds in vegas or something. Some winters we get cold east that's so oppressive that it suppresses storms south and won't allow them to track up the coast to give us snow, miserable, miserable look. Just ripe cold with no moisture. You can look back at some of those harsh winters and really see how cold it was with no snow. Putting it very simply, we want a healthy medium of cold and an active jet to provide the moisture, and we're in business for chances. But as SnowGoose pointed out a post above, we can still get storms with one of these not in a favorable phase.

[superjames1992]

Cool. So it might snow in the next few months.

Will snow, my dear. Will. Keep the faith.

[Webberweather53]

As a whole the AO is way more important, a -NAO only guarantees you cold if the pacific and AO is cooperating, if neither or only one is, the -NAO may only serve to dampen what may otherwise be a blowtorch. The AO of course usually goes in tandem with the NAO but not always, the winters of 93-94 and 13-14 both saw a pattern in which the AO and NAO can easily be in opposite phases

 

On the opposite end of the spectrum, a +NAO doesn't mean you're going to torch either. A +AO/+NAO in Feb during an El Nino winter usually is overridden by the ENSO forcing that naturally tries to keep temps cooler than normal on the eastern seaboard February & the composite shows this w/ seasonable-below average temps in the eastern US despite the unfavorable indices...

[pcbjr]

Will snow, my dear. Will. Keep the faith.

 

how much imby

[NCSNOW]

I always root for all 4 +pna, - nao - ao, weak eastern based ek nino

[CAD_Wedge_NC]

Cool. So it might snow in the next few months.

That's a slam dunk for my area. We haven't gone snowless in a winter since records were kept. Certainly not in my 50 years.

[Cold Rain]

On the opposite end of the spectrum, a +NAO doesn't mean you're going to torch either. A +AO/+NAO in Feb during an El Nino winter usually is overridden by the ENSO forcing that naturally tries to keep temps cooler than normal on the eastern seaboard February & the composite shows this w/ seasonable-below average temps in the eastern US despite the unfavorable indices...

]

So what's the story with all the Tweets back and forth with HM today? We in trouble?

[NCSNOW]

I always root for all 4 +pna, - nao - ao, weak eastern based ek nino

Ugh typing on the phone is killer , anyway of the 4 give me the east based weak nino and + pna and I'll take my chances. The - AO and -NAO are icing on the cake. Looks like the euro ens are split 50-50 on cutter or solution like the op has. So expect some see - sawing the next several euro op runs.

[deltadog03]

Question for all my AMX family...I cut a video explaining the wedge and how it affects the SE, and hinted on the trends of next weekend.  Its 7 min long...LOL would yall like to see it? or nah?  Won't hurt my feelings either way.  

[pcbjr]

Please.

[Reb]

Of course we would, Delta

[SouthWake33]

Question for all my AMX family...I cut a video explaining the wedge and how it affects the SE, and hinted on the trends of next weekend. Its 7 min long...LOL would yall like to see it? or nah? Won't hurt my feelings either way.

Yes, please