December Forecast Discussion

[Bevo]

That was the pattern in 10-11 as well, if it wasn't for the -AO we would have torched that winter. The-PDO regime is a long lasting dominate cycle, however, it is not as bad as some make it out to be here. We're just seeing a very extreme case of it for the last few weeks. A strong -AO can overcome the pacific and in some cases even change the PNA pattern.

+1

Is it not the same pattern we've been in for the last 7 months that have brought at or below temps to the SE? Now suddenly it changes - literally - right at winter to where it will not do what it has been doing since Spring?

[LithiaWx]

Clarification: I meant it doesn't look like a torch pattern as we get to midmonth+. I was commenting on the medium range forecast as opposed to the recent past being that this is a forecast disc. thread. My bad for saying it isn't a torch as that is not good wording. I was using present tense referring to what the present models are showing for the medium range. No question it has been torchy early this month. Also, these next three days do look fairly torchy though not near records.

Record high for atlanta tomorrow is 76 we are forecast to hit 72. Not that close but not too far either. December has been a seasonal torch to date and we still have some more mud to trudge through. December is gone and so is 33% of met winter.

[Carvers Gap]

That was the pattern in 10-11 as well, if it wasn't for the -AO we would have torched that winter. The-PDO regime is a long lasting dominate cycle, however, it is not as bad as some make it out to be here. We're just seeing a very extreme case of it for the last few weeks. A strong -AO can overcome the pacific and in some cases even change the PNA pattern. People forget, some forecasters went very warm that winter based on the PDO/la-nina combo and busted big.

As we get deeper into winter, does a strongly negative AO have greater ability to overpower the pattern? Totally agree about 10-11, I was shocked it was that cold. Last winter showed us what happens without the negative AO. The -PDO has generally cooled the pattern over E TN during the past few winters, so I am not displeased with it. Basically, I am looking at one feature(which may be a result of the -PDO) and that is the Alaska set-up. Seems like that is driving the pattern downstream with the jet.

[Carvers Gap]

+1

Is it not the same pattern we've been in for the last 7 months that have brought at or below temps to the SE? Now suddenly it changes - literally - right at winter to where it will not do what it has been doing since Spring?

Actually, the pattern has been extreme here in NE TN. Record rains during one month. All-time record highs. That heat mid-summer was brutal. Cooler temps during the last few months. My guess is that the extreme pattern will repeat. The question is, when? When it flips, it will flip quickly. After the heat of late June and early July, we moved back to a prolonged cooler pattern. Wouldn't be surprised if that happens here. That said, when the pattern over Alaska locks in it is tough to move in winter. That is why I am interested if the signal from the -AO will eventually overpower the pattern. I think that may be our hope as Hickory states.

[CandymanColumbusGA]

Clarification: I meant it doesn't look like a torch pattern as we get to midmonth+. I was commenting on the medium range forecast as opposed to the recent past being that this is a forecast disc. thread. My bad for saying it isn't a torch as that is not good wording. I was using present tense referring to what the present models are showing for the medium range. No question it has been torchy early this month. Also, these next three days do look fairly torchy though not near records.

Ha! My bad! I read the thread title wrong... Lol! I apologize.

You are correct about it not being torchy for midmonth for all the reasons you said earlier. This zonal flow will allow us to be near normal, though slightly above for some. It is just how this winter has gone. I will say that the snowpack and cold in northern Canada is impressive... If we can send that to our side of the globe then we'll be in business. However... If it dumps it towards Europe, which has been the case from what I'm catching up on, then it doesn't bode well for us in the Deep South in the near term (possibly the next week and a half to two weeks).

[GaWx]

That was the pattern in 10-11 as well, if it wasn't for the -AO we would have torched that winter. The-PDO regime is a long lasting dominate cycle, however, it is not as bad as some make it out to be here. We're just seeing a very extreme case of it for the last few weeks. A strong -AO can overcome the pacific and in some cases even change the PNA pattern.

Brandon,

I agree. I think that the best way to put it is that when there is a -PDO/-PNA/+EPO Pacific and a -NAO/-AO Atlantic/Arctic, there will be a battle. Sometimes, the Pacific will win and sometimes the blocking will win. Often, there will just be back and forth and/or near normal regarding temp.'s on average for the long haul. With this setup, there would probably typically be some torch periods as we've just had and there'd probably be some cold periods for which the flow is not zonal, which I'm hoping for at some point(s) this winter. I am admittedly a bit concerned that the PDO seems to be falling back to more solidly - levels. This isn't a surprise considering that GOA pig low. Hopefully, that will reverse.

Looking at 10-11, Dec. and Jan. were, indeed, cold (especially Dec. in terms of anomalies) despite the -PDO and a solid -PNA in Dec. Now, Jan. did have a solid +PNA that helped it.

Edit: Dec. 10 was real anomalous with the 2nd most neg. PNA since 1950 of any Dec. and it being very cold. This is soooo atypical as there clearly is a rather strong partial correlation for SE cold with a +PNA. It accomplished that due to a combo of the 2nd most negative AO and 3rd most neg. NAO since 1950 being able to dominate.

[Carvers Gap]

For the record, I thought December would be cold based on a weak Nino - which is obviously not happening. I just hope we don't go Nina again because I don't like hot, hot summers. I can deal with warm winter even though I like snow. Oppressive heat here in the northern TN Valley is not that common and not that welcome.

[GaWx]

For the record, I thought December would be cold based on a weak Nino - which is obviously not happening. I just hope we don't go Nina again because I don't like hot, hot summers. I can deal with warm winter even though I like snow. Oppressive heat here in the northern TN Valley is not that common and not that welcome.

I agree about the lack of the Nino. There's little question in my mind that not having the Nino isn't a good thing since it typically increases the frequency of a +PNA. Just look at history. Weak Ninos coupled with good blocking, especially those following Ninas, have produced a sig. % of KATL's coldest winters. Until the weak Nino died, I was still keeping a very cold averaged DJF on the table as a realistic possiblity. Now, that doesn't mean I don't think we could have some very cold periods later this winter when blocking is strong and the doodooey Pacifc lets up.

[griteater]

NCEP and Euro MJO phase plots look a little more robust with taking the MJO into phase 1 next week

[tarheelwx]

Is mjo phase 1 a good thing?

[Tacoma]

guys i'm sitting back and waiting. winter of which It IS Not Winter Yet will arrive. everyone is in to much of a hurry for the season to change. I've lived here all my life in the mtns. of nc and winter never really arrives until Jan. we've been spoiled by the couple of decembers where we had snow. GIVE IT TIME GUYS AND DON'T PANIC. Oh and the squirrels have been busy this week, very active if you sit and watch them.

[Jon]

Is mjo phase 1 a good thing?

8-3 basically.

[HKY_WX]

Brandon,

I agree. I think that the best way to put it is that when there is a -PDO/-PNA/+EPO Pacific and a -NAO/-AO Atlantic/Arctic, there will be a battle. Sometimes, the Pacific will win and sometimes the blocking will win. Often, there will just be back and forth and/or near normal regarding temp.'s on average for the long haul. With this setup, there would probably typically be some torch periods as we've just had and there'd probably be some cold periods for which the flow is not zonal, which I'm hoping for at some point(s) this winter. I am admittedly a bit concerned that the PDO seems to be falling back to more solidly - levels. This isn't a surprise considering that GOA pig low. Hopefully, that will reverse.

Looking at 10-11, Dec. and Jan. were, indeed, cold (especially Dec. in terms of anomalies) despite the -PDO and a solid -PNA in Dec. Now, Jan. did have a solid +PNA that helped it.

Edit: Dec. 10 was real anomalous with the 2nd most neg. PNA since 1950 of any Dec. and it being very cold. This is soooo atypical as there clearly is a rather strong partial correlation for SE cold with a +PNA. It accomplished that due to a combo of the 2nd most negative AO and 3rd most neg. NAO since 1950 being able to dominate.

I agree, all things being equal you want a netural or slighly positive PDO/-AO combo. That allows a good combination of moisture and cold. If you get the huge PNA ridge and the -AO, you get record cold/dry. When you have this upcoming ao/pdo battle, it will probably be topsy turvy. I could see a very warm/stormy week dec 15-20 and then snow/cold the week after. So we'll see what happens.

[HKY_WX]

As we get deeper into winter, does a strongly negative AO have greater ability to overpower the pattern? Totally agree about 10-11, I was shocked it was that cold. Last winter showed us what happens without the negative AO. The -PDO has generally cooled the pattern over E TN during the past few winters, so I am not displeased with it. Basically, I am looking at one feature(which may be a result of the -PDO) and that is the Alaska set-up. Seems like that is driving the pattern downstream with the jet.

Well from a practical standpoint you have more cold dense air near the higher lattitudes during winter, so any major displacement of this air would cause a greater impact on the pattern than in the middle of summer. I am excited about the coming sunspot minimum in future years as I think there is some sort of connection there b/n the AO/sunspot. I want to do more research into that. We could be going into a long term min and that may really good news for winter lovers.

[nchighcountrywx]

Agree upcoming MJO Phases look promising.

Let's see what happens.

[IWC]

I guess it on to the next 10 days or (240hrs)

[BullCityWx]

I think the only question left to answer is how big the positive departures are for this month. Are we talking minimal damage or are we discussing top 5 all time warmest Decembers?

[jburns]

Oh and the squirrels have been busy this week, very active if you sit and watch them.

Of course they are. They think it's spring.

[Tacoma]

Of course they are. They think it's spring.

No getting ready for winter! They don't bury nuts and acorns in the spring.

[Tacoma]

8-3 basically.

which is the best mjo, 8 or 3 or does it matter?

[dsaur]

Lol... It has been 70 or above every day in December. A good 8-15 degrees above average. I don't know about you... But that's a torch to me. Also, the northeast, where I'm currently vacationing, has seen some balmy weather with mid 60s in NYC on Tuesday when I was there and low 70s in DC. It's been warm for much of the country.

I'll admit right now that I haven't been keeping up with the models over my vacation, but at least I'll be bringing some colder weather down south with me! Actually, this will be more seasonable weather, nothing really cold. I'm still not seeing a whole lot of hope for REAL cold weather, but, like you mentioned, rainier days are ahead. Hopefully the southern stream can work some magic for us, rain-wise, and our friends to the north can get something that times nicely with some cold air. Other than that, I will gladly welcome the average temperatures next week as it has been WAY overdue for my neck of Georgia.

I hope you are enjoying being in the city, and hanging out at some luxury hotel, getting pampered, while I'm down here suffering in this heat, working hard to get us some rain, lol.

I hope I'm about to get us a nice couple of inches of the gulf falling into some Cad late next week, for a more seasonal feel to things, and if we are real lucky some actual cold rain, for a seeming near miss And even if it is 70, the rain will still be the most important thing. So you just have fun up there, knowing the Moles never sleep, and neither does Tony, always trying to provide some interesting weather for you to wax elequent over when you are on the Tv machine.

And, please, for me, go to MOMA, and say hey to the Pollacks, and Seurats from me. I always go first thing when I get to the city, and if I have time, back again before I leave. One of the best museums in the world to my mind, though I haven't seen them all, lol!

Meanwhile, winter in the south I have known, is usually a roller coaster, not this, or that, so unlike last winter, an aberration, I hope, I think this winter will be more normal, which would lead me to bet on Jan for cold and sleet. Always remembering blocking is good for someone to get cold, and it doesn't always mean us!! But occasionally it will be. And a flow off the gulf is always good for us, even it is is hot, if it brings the rains.

And I don't think Larry has written off all of Dec. because he knows better than most, that climo smiles on the week after Xmas. I still wait for New Years 63/64 redux!! T

[jburns]

No getting ready for winter! They don't bury nuts and acorns in the spring.

lol They were busy last year too. They should have enough nuts stored for at least 10 years.

They do bury their nuts in the spring. I'm not sure about acorns.

[Carvers Gap]

Can anyone post the Euro? I hear it looks very warm. Also, how are its weeklies looking?

[Wow]

12z Euro: A battle between a -NAO and -PNA. Aleutian ridge still hanging around. Cold shots with warm up inbetween.. we need a long wave trough here to bring the Pacific back to a sustained cold setup.

[MillerA]

From his twitter feed today.

Allan Huffman ‏@RaleighWx

Persistent trough in Gulf of Alaska/wet coast, means we will need strong -NAO to keep cold pattern. CFS/Euro weeklies torch by early Jan

Allan Huffman ‏@RaleighWx

While I am still not expecting a deep freeze, most of the US will turn cooler the week before X-mas. But how much lasting power?

[Southern Track]

I didn't think the afternoon Euro op looked that bad. But what do I know.

Potential at the end of the run. Close call cold with precip.

[Cold Rain]

I didn't think the afternoon Euro op looked that bad. But what do I know.

Potential at the end of the run. Close call cold with precip.

It was crap. That's what it was. Unless you don't like any hint of a sustained cold pattern. In that case it was fabulous.

[FoothillsNC]

I don't like what I'm seeing in the Pacific. Also, the Atlantic looks unusual with the cold undercutting Greenland and connecting with the Cold Europe. This means the brief pattern change underway now (PAC ridge) will collapse immediately. The blocking that (at first) had a shot at being mostly in Greenland is now probably going mostly to Scandinavia and Russia, but there will be a little above normal heights in Greenland and Eastern Canada around days 10 through 15. But by far, you can can see on Allans model site the 850 temp anomalies are in the West and centered again in Alaska and western Canada, and the Southeast and East actually has above normal 850 temps during days 8 through 15, really for most of the next 16 days probably. So the height field is very misleading, this is a unique case of that too.

The reason being is the Pacific onshore flow...it will produce a somewhat supressed flow and zonal, but mostly pacific air. Notice how the models got rid of the cold Plains lately? And without the +PNA, our air is going to be coming from the west, not northwest. There will be a quick shot of cold behind this next front on Tuesday , but again, the Carolinas and Georgia mostly miss that, its centered west of the Apps. (Rain too!). GRRR. The drought has really strengthened lately in GA/NC/SC and I don't see much end to that. At first I was hopeful that the supressed flow would bring rains here, but I'd bet most of it is west of the Apps, but the GFS and some ensembles do bring better chances by day 10 with that front, but as usual when things get closer , they fade here.

To combat the bad Pacific, we need a super strong -AO/-NAO pattern, and really centered in Greenland and west based, but that would mostly keep us at average, as we'd need strong +PNA to dislodge the cold air to move south, and so far, it's not showing up. We will end up with an Aleutian HIGH, not low, which is what is needed to produce western ridging, and eastern troughing. The exact 180 degree opposite of a classic Winter pattern. Now no pattern lasts forever, even last Winter there was that one storm that got Ky, Va, W VA, and northern NC with some nearly annual snow totals, and with the tendency for blocking around Greenland, I highly doubt we have as bad a Winter as last year. Just there is not much hope this December though, and it's really resembling last year for anomalies (except the slight pos. anomaly in Greenland/east Canada).

We've had 3 straight months of mostly below normal temps in the Southeast and this warm up was expected, but now that we're entering Winter, the warm anomalies will really start to show themselves , relative to averages, and I'm almost certain NC/SC/ and especially GA will have a very warm December compared to normals, when this month is over. The only saving grace may be clouds with a pretty active flow.

If we could ever find a big block in Greenland, then I think the Southeast would have it's chance for a good snowstorm, even in a sea on non-Winter like weather, a brief Winter period. Our chances are much improved over last year of that happening, for sure, but like I said the Pacific is working strongly against us right now, and the blocking is heading to Russia, not Greenland, so thats a major strike for a while.

I hate that we lost the weak Nino chances for the Winter b/c that would have helped immensely on +PNA with some staying power, even with the -PDO period.

On these images of the Ocean Temp anomalies, you can see clearly since October, there has been a steady trend in growing the cold pool around the Gulf of Alaska. You can also see the Nino fade out almost completely. The only positive for blocking is that the waters around Greenland are still above normal, and you can see how the next 10 days of modeling hints atleast a little of that for some very weak -NAO, but I sure don't like a very strong large cold pool in the Gulf of Alaska like this, and that is growing, not declining. Thats a sign of serious -PNA and -PDO.

OCT

NOV

DEC

Now what could happen at some point late month or sometime this Winter (and I think it will) is a strong storm develop in the 50/50 position at just the right time to pull down cold air on the backside, while pumping up a Greenland Ridge...and that pattern could be when the Southeast gets it's shot. So far, I don't see it though. But this is a very volatile pattern and has an unsual alignment of dueling indices, so things could change abruptly , but we'll see.

Oddly enough, one of the best anologs to this type of unsual index configuration/ENSO is 1969....which happens to be the biggest snowstorm ever to hit my county in NC. HA!

[nchighcountrywx]

Thanks for the analysis Robert. It is appreciated.

Looks like we are going to have to thread the needle and be thankful and blessed by what snow we can get out of this winter.

[Wow]

Thanks for the analysis Robert. It is appreciated.

Looks like we are going to have to thread the needle and be thankful and blessed by what snow we can get out of this winter.

At least for most of December. For all we know, we may get a 2 to 3 week period of some real cold and experience a big snow. I don't think people should swing to the extremes on the prospects of the