December and January Pattern Discussion

[Carvers Gap]

it would be nice to see a cutter really bomb.

 

From December 24th onward, that big high over the Hudson basically rotates cold air around it like spokes on a bicycle.  That can be a good pattern for all of the SE....IF it sags far enough southward.  Something to watch on future runs.  The Euro is having nothing of that.  I am leaning towards the GFS at the moment FWIW.  That is dangerous though.  But the pattern makes sense.  Would actually set the stage for a rare overrunning event west of the Apps IMO.  Long way out there.  Plenty of time to watch it.  Does not appear the pattern is going to go dry.  It is just a matter of time before that cold air in Canada interacts w/ something cutting under it.  Now, where that happens...east of the Mississippi.  Bout all I have there.

[Carvers Gap]

On the 18z GFS, the SE ridge basically gets bulldozed after Dec 24th from what I can tell.

[jaxjagman]

If you look at the 500 12z anomalies,the GFS kisses the Yucaton with the SER.This is a huge spread from the Euro being off the east coast of FL.,i'm rooting for the Euro.

[jaxjagman]

The Euro esm. showed no hope through the 29th,maybe a couple days below freeze for Nashville,other than that,blah

[tnweathernut]

Morning thoughts.

1. Models are trending away from a record breaking blast of cold air around Christmas.

2. Indices are still indicating a +NAO, but forecast drops of the AO toward neutral and make a run toward a +PNA . That alone may be enough to give an opportunity to the mid south at some point during the last week of 2013.

3. I still don't see any hope in the Atlantic, but when you think about it, it's only mid dec. if it takes till mid January to score some blocking that would put us in the heart of the winter....

4. The warm water in the North Pacific seems to have locked in our -EPO/-WPO. I hope we don't have to lose this in order to reshuffle the Atlantic. It's been our biggest saving grace so far. If that flips we would be in trouble for sure.

5. I like the look of a southern stream. After the last two winters its a welcome sight.

6. This winter is shaping up completely different from the last two. That in itself is reason for optimism!

Sent from my iPhone using Tapatalk

[Cold Rain]

Morning thoughts.

1. Models are trending away from a record breaking blast of cold air around Christmas.

2. Indices are still indicating a +NAO, but forecast drops of the AO toward neutral and make a run toward a +PNA . That alone may be enough to give an opportunity to the mid south at some point during the last week of 2013.

3. I still don't see any hope in the Atlantic, but when you think about it, it's only mid dec. if it takes till mid January to score some blocking that would put us in the heart of the winter....

4. The warm water in the North Pacific seems to have locked in our -EPO/-WPO. I hope we don't have to lose this in order to reshuffle the Atlantic. It's been our biggest saving grace so far. If that flips we would be in trouble for sure.

5. I like the look of a southern stream. After the last two winters its a welcome sight.

6. This winter is shaping up completely different from the last two. That in itself is reason for optimism!

Sent from my iPhone using Tapatalk

Hi Folks! Things are off to a great start over here with some great disco already. All of these points are excellent points, especially 1 - 6. This is a completely different winter than the last two, and I think the SE in general, but particularly your area stands to do pretty well when it's all said and done.

Like was just mentioned, the models keep pushing the mother load back. But that's not unexpected with no blocking. If we get a tall PNA ridge, that could do the trick also. So if we start to see that feature build in the modeling (and not continue to get pushed out in time), then a LR forecasted Arctic outbreak would have more credibility. Otherwise, any such progged Arctic invasion should continue to be muted as we get closer to it and should be viewed with skepticism.

[Carvers Gap]

How many times have we had cold and the models look to continue it endless, only to suddenly have the models flip to warm?  I am not sure if that is termed feedback.  But computer wx models have a tendency to perpetuate a pattern and miss a flip.  I see no wx reasons for a flip, but am watching for that type of flip.  The NAO, especially the AO, and PNA all are peaking at territory that would be favorable to cold moving East - as tnweathernut alluded to.  Again, I think we really need a storm to wind-up, deepen and cut into that cold air.  I think this would shake up the pattern and drive cold air East, even if momentarily. 

[tnweathernut]

12z Euro finally brings the cold on day 10. Nice ridging building out west, still a terrible Atlantic. Check out the 915 just to the east of Greenland though! Wow.

Sent from my iPhone using Tapatalk

[Carvers Gap]

Here are two looks at the ENSO status for Dec 9.  Looks like neutral through mid-summer 2014 w/ a run at El Nino late.  I post this because it could be interesting later in the winter season if the eastern Pacific temps continues to warm.

[Carvers Gap]

Here is another look at the ENSO.   Can someone PM me on how to post two images in the same post...with decent spacing between them?

[John1122]

This looks like the beginning of something decent. Far better than the 6-10 day. Love the above normal west coast.

 

[tnweathernut]

I think anyone hugging models will pull their hair out over the coming couple of weeks. See the below 12z GFS at hr 180

and then the 18z at hr 174.

Subtle differences in the strength and orientation of the ridge near the west coast and you get BIG differences with interaction of the streams and sensible weather.

It's going to be a long winter for forecasters me thinks.

Sent from my iPhone using Tapatalk

[Carvers Gap]

I think anyone hugging models will pull their hair out over the coming couple of weeks. See the below 12z GFS at hr 180.

and then the 18z at hr 174.

Subtle differences in the strength and orientation of the ridge near the west coast and you get BIG differences with interaction of the streams and sensible weather.

It's going to be a long winter for forecasters me thinks.

Sent from my iPhone using Tapatalk

Good point. The good thing is...looks like a trough is trying to set-up shop in the east around day 9. I am concerned a shallow trough will be the outcome vs a deeper trough. Today's wx models didn't look too bad. Of course we could move to a suppressed pattern if that HP settles down - unlikely at this point.

[Cold Rain]

Good point. The good thing is...looks like a trough is trying to set-up shop in the east around day 9. I am concerned a shallow trough will be the outcome vs a deeper trough. Today's wx models didn't look too bad. Of course we could move to a suppressed pattern if that HP settles down - unlikely at this point.

The really good thing is the PNA ridge that's been forecast the last couple of days. It's starting to be a consistently modeled feature, which certainly raises the credibility that it'll be there at some point. While it won't really overcome the lack of blocking, it will help drive cold air masses south...and it may even bring a few short waves with it.

[Met1985]

Good discussion here about the upcoming g pattern. I think the  pac cooperating will help a lot in the future if the pv is in the  right spot. 

[jaxjagman]

I'd say the GFS sped things up this run

[jaxjagman]

LOL..like someone mentioned before i wouldn't want to be a met right now watching the GFS and trying to make a forecast

[Carvers Gap]

Some signs on the 0/6z GFS/Euro as well that the upcoming pattern is going to bottle the cold air mass up in Canada. With the Atlantic unfavorable, it is going to be tough to sustain any cold. Our hopes may be riding on a + PNA. Time will tell.

[franklin NCwx]

12z Euro finally brings the cold on day 10. Nice ridging building out west, still a terrible Atlantic. Check out the 915 just to the east of Greenland though! Wow.

Sent from my iPhone using Tapatalk

that's our problem Icelandic low. Keeps a trough in Greenland and pumps a Scandinavian ridge. A Scandinavian ridge= southeast ridge we need a 50/50 low with a ridge in Greenland.

Ensembles have been all over the place in the 10-15 day range. Maybe a pattern reshuffle?

[Stovepipe]

Latest from Don Sutherland for those that don't frequent the general boards.

 

 

Mid-Month Update:

 

To date, the month has been characterized by an EPO-/AO+ pattern. Today, the AO was +4.201. That breaks the daily record high of +3.159, which was set in 2006. Nevertheless, unlike 2006, a snowstorm brought more than a foot of snow across parts of Maine. In 2006, the EPO was +1.589. Today, it was approximately -1.3.

 

Nevertheless, the ensembles have been hinting that the EPO could become more neutral as December winds down.

 

 

To date, the predominant EPO/AO pattern has produced outcomes fairly close to those shown for the partial teleconnection cases (excluding ENSO) for the month of December (Message #204 of 11/30). If, however, the more neutral EPO materializes, one could see the cold anomalies lift into Canada, and milder anomalies prevail, on average, during January. The 360-hour reforecast ensembles hint at a possible pattern evolution toward a milder January outcome. Fortunately, at this point in time, the skill level of both is low.

 

 

Finally, the snowfall that has blanked parts of the northern Mid-Atlantic this month, including the snowfall that appears likely on Tuesday courtesy of two clipper systems racing eastward, is providing a hint that the northern Mid-Atlantic region into southern New England may experience normal to above normal snowfall for the winter. For example, Philadelphia has already received 11.1" snow this month. 8/9 (89%) of winters that received 10" or more snowfall in December since 1872 wound up with 20" or more seasonal snowfall. and 6/9 (67%) had 30" or more. The sample size is small, but the probability is very high, so odds probably lean toward a winter with 20" or more snowfall.

[tnweathernut]

It will be interesting to see if the idea of the EPO moving toward neutral works out. If it does, I would think we have to have a warm spell.  Very few winters are wall to wall cold in the southeast so at some point the EPO/WPO has to relax a bit.  However, there is so much warm water in the north Pacific I'd like to think even if/when it does, it's a temporary condition.  Similar to the vortex that was in Alaska the last two years due to the COLD COLD waters in the Pacific, I can't imagine we don't drive the EPO back strongly negative at some point in the near future. 

 

I am hoping we can get the Atlantic to relax a bit and get us toward neutral for the AO and NAO toward the new year. It would be nice to see the Atlantic "blink" as we are currently seeing with the forecast of the EPO.

[Clarksville Snowman]

We need the EPO/WPO to tank out again, hopefully the PNA will come toward neutral. Would like to think at some point soon the AO and NAO would trend toward neutral. Even if they don't if we can get that PNA ridge to flex and the EPO to tank again after relaxing we may have something worth watching. I still feel confident the EPO will go negative again that in itself gives us chances even with transient cold shots.

[tnweathernut]

Somehow I posted this in the weenie thread. I don't really know why we need weenie voting, but oh we'll. I will repost my thoughts again in the correct forum.

I have seen a LOT worse looks than this. A nice Aleutian low pumping a ridge around the west coast, sufficient highs in Canada, on the slide into the US, and a pocket of energy out west at 216.

Sent from my iPhone using Tapatalk

[Stovepipe]

Robert Gamble posted an interesting write-up on the free area of his site today that is worth a read:

 

http://wxsouth.com/?cat=144

 

Thinks we will see the indices flip hard after Christmas.

[franklin NCwx]

18z gfs was close to a phase for Christmas eve. Might be something to watch and we can see some snow fall on Christmas eve/Christmas day. Ensembles look like a more favorable pattern after Christmas too.

[franklin NCwx]

Robert Gamble posted an interesting write-up on the free area of his site today that is worth a read:

http://wxsouth.com/?cat=144

Thinks we will see the indices flip hard after Christmas.

JB and Joe aleo have talked about the ao and nao going negative in January.

[tnweathernut]

Euro control run at 360. JB shows it as blocking trying to form over the top. I view it as having entertainment value ONLY. Hoping to see this kind of blocking within day 7 soon.

Sent from my iPhone using Tapatalk

[jaxjagman]

Cool tool here,one of the mets posted it the other day on the main board,you can change the url also

 

Edit:It updates every 3 hrs and hold your left click down and you can scroll the world

 

 

 

http://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=-115.71,38.12,412

[jaxjagman]

[John1122]

Brutally ugly indices except for the PNA. We need to get rid of that stupid vortex over Iceland. It's like pouring water down a funnel. Unless there's some spill over, it mostly just pours right into that thing.