GaWx

Ladies and gentlemen, can I have your attention, please? The results are in and we did it. The MJO went back into phase 8 on Dec 15th, the coldest day of the season to date! Let the celebrations begin! The weenies are gonna party like it’s Feb 1899!

 Natural gas closed up nearly 4%, easily its best day since Dec 5th. This is largely based on today’s forecast speculation that the forecasted dominant warmth may not be as widespread, intense, and/or long lasting in the E US as thought yesterday thanks largely to the newly forecasted strong -NAO.

 The model consensus is currently forecasting the strongest -NAO on Christmas as well as surrounding days since way back in 2010! In stark contrast, these 6 had a strong +NAO: 2011, 13, 15, 16, 23, and 24.

12Z GEFS strong -NAO that starts in just 5 days (12/22) and is the strongest -NAO for days 5-16 averaged out on any GEFS run back to at least Oct 31st:

Compare this to the 0Z 12/12/25 run: 12/22-28 were 0 to +0.5 instead of -1 to -2

 Check out the widespread much lower H5 for nearly the entire E US on the 12Z GEFS vs the 6Z GEFS as of 0Z 12/30 helped mainly by the apparently even stronger -NAO:

These images show that the GEFS was too slow in showing the transition from the very strong -PNA of Dec 2021 to the strong +PNA of Jan of 2022:

 12/15/21 GEFS PNA forecast was ok

 

But the 12/26/21 GEFS PNA forecast, which goes through 1/9/22, had all members 0 to -2 for then. The actual 1/9/22 ended up being +0.2. So, it was too slow in predicting the turn to a +PNA:

12/31/21 GEFS PNA forecast out to 1/14/22: finally turned to +PNA but not positive enough as 1/14 was actually +0.7 vs this forecast for ~+0.4:

1/5/22 GEFS PNA forecast out to 1/19/22: not positive enough as 1/19 was actually +1.0 vs this forecast for only ~+0.1:

This shows the actuals for the entire Dec-Jan 2021-2:

 Is NG finally bottoming? It’s currently up over 3%. If this were to hold, this would be the best day since Dec 5th, the day it peaked. There’s been only one other up day since then, Dec 9th, when it closed up 1/2% and then was followed by more big down days as the maps kept insisting on warmth dominating the US.

 Why do I think it’s up today? The AO and especially the NAO forecasts have gotten significantly more negative than yesterday’s more neutral forecasts as per my post three above this. A strong -NAO lead to much colder 0Z and 6Z GFS after Christmas fwiw. This kind of thing with the -NAO/-AO happened early this month. 

 From NOAA, one can see how much the NAO has dropped since just yesterday on the GEFS:

Yesterday’s GEFS NAO (12/16);

Today’s GEFS NAO (12/17): note the biggest changes are for 12/22-26, only 5-9 days out. Yesterday they were ~0 while today they’re -0.7 to -1.0:

1 hour ago, MJO812 said:

Not the eps and gfs.

Here’s the 0Z GEFS NAO: week 2 of this and the EPS for the mean (green line) have gotten much more negative just since 24 hours earlier and are now close to the strongest -NAOs of all runs at least since Oct 31st per WxBell’s history that goes back that far: look at green line

24 minutes ago, Stormchaserchuck1 said:

Yeah, it neutralizes. If you start from the most extreme point, it should come toward evening out. Still, ENSO is a powerful factor so I would have thought the +PNA January's would be more extreme. 6/7 were +PNA January's though, and since 1980, 5/5 were +PNA January's. It neutralizes the other side/point. Still, a net neutral signal in January-ENSO is something. Will be interesting to watch and see how this January evolves, I do know that Natural Gas led these Euro weeklies and all this warm stuff for Jan by some time! 

Chuck,

 The strongest Jan +PNAs for +ENSO were these:

1977: +1.8 from +0.5 in Dec

1983: +1.2 from +0.8 in Dec

1987: +1.0 from +1.4 in Dec

1992: +1.3 from +0.5 in Dec

2003: +1.3 from +1.6 in Dec

2010: +1.3 from +0.3 in Dec

2016: +2.0 from +0.8 in Dec

 
 So, avg Dec preceding +1+ +ENSO Jan PNA was +0.8. But avg Jan following +1+ +ENSO Dec PNA was only +0.5 though it was skewed by 1954.

7 minutes ago, Stormchaserchuck1 said:

Hey Larry, 

All of your examples 1950-1980 were -PNA January. Then you have only 7 examples after 1980.. now 7/7 is a strong point, I agree, but it might be in the field of random if you consider what ENSO is/does. A good test would be the opposite: What did January do in +ENSO after a +PNA December? What there a difference 1950-1980 and after 1980 (I haven't run the data, but will say probably not - just guessing). My map in the last post includes that, so since it rolls forward to a pretty strong N. Pacific ridge in January, I'm thinking it probably doesn't check out the other way around: (does +PNA Dec lead to -PNA Jan in +ENSO?).

Chuck,

 Let’s see. I’m looking now at +ENSO 1+ PNA Decembers to Januaries: there were 8 cases:

- 1953-4 +1.3 to -1.1: drop of 2.4

- 1963-4 +1.8 to +0.2: drop of 1.6

- 1969-70 +1.8 to +0.6: drop of 1.2

- 1986-7 +1.4 to +1.0: drop of 0.4

- 1997-8 +1.2 to +0.7: drop of 0.5

- 2002-3 +1.6 to +1.3: drop of 0.3

- 2006-7 +1.9 to +0.7: drop of 1.2

- 2023-4 +1.2 to +0.5: drop of 0.7

- avg drop 1.0

- avg drop much higher for 1st 3 cases (1.7) vs last 5 (0.6)

———— 
Your thoughts?

23 minutes ago, Stormchaserchuck1 said:

I don't really get this "negative ENSO turned -PNA to +PNA" since 1980 thing. 

1. Why does it only start in the 1980s? Data was not unreliable before then, so it's not like you're starting from a blank point. I think a lack of examples increases the odds of random. If it didn't work before 1980, that's telling, not an ignored difference.

2. That's not what Negative ENSO does. Negative ENSO does not support a +PNA in January. The Hadley cell is extended in the N. Pacific in La Nina more often than not, and that supports -PNA. 

Since we are having such a strong -PNA December, here is a fun roll forward. This is what 500mb January looks like after -PNA Dec.. this is a total composite of 73 years, both - and + signs considered, going back to 1948:

That's an Aleutian ridge in the mean for January. But the ridge is a little further NE, which makes January a cold month for a lot of the US. 

The reason why it will sometimes switch is the MJO runs if 45-day cycles and Kelvin and Rossby waves sometimes run in 45-60 day cycles. We don't have a strong phase of those things now -- it will be interesting to see if we do go more +PNA after the 1st week of January. I think you are discovering a high mathematical random skew. 

Hey Chuck,

 Here’s a post I made on Friday going all of the way back to 1950 that shows that for some reason (possibly randomness) the sharpest rises from a sub -1 PNA Dec to Jan have occurred since 1984-5 (CC related?):

“This implies the realistic chance for a sub -1 Dec PNA. Whereas that’s bad news for those wanting E US cold in the 2nd half of Dec in the MidAtlantic/OH Valley south, it isn’t necessarily bad news for January prospects. That’s because in the vast majority of cases for -ENSO, the PNA in January rose sharply from Dec:

PNA Dec/Jan for -ENSO for strongly -PNA in Dec

- 1955-6: -2.1/-1.3 (rose 0.8)

- 1961-2: -1.2/-0.1 (rose 1.1)

- 1964-5: -1.7/-0.2 (rose 1.5)

- 1971-2: -1.5/-1.4 (rose 0.1)

- 1984-5: -1.6/+1.6 (rose 3.2)

- 1996-7: -1.2/+0.6 (rose 1.8)

- 2008-9: -1.4/+0.6 (rose 2.0)

- 2010-1: -1.8/+1.3 (rose 3.1)

- 2012-3: -1.0/+0.6 (rose 1.6)

- 2013-4: -0.9/+1.0 (rose 1.9)

- 2021-2: -2.6/+1.0 (rose 3.6)

So, average PNA rise Dec to Jan for these was a whopping 1.9!

 Today’s GEFS is progging ~-1.7 PNA for Dec as a whole. That would be ~5th strongest -PNA since 1950. But what were similarly strong -PNA Dec followed by in Jan since 1984-5 during -ENSO?

1984-5: from -1.6 to +1.6

2008-9: from -1.4 to +0.6

2010-1: from -1.8 to +1.3

2021-2: from -2.6 to +1.0

 All 4 of these Januaries were cold in the E US.

The radiational cooling in much of the SE has been quite impressive the last 4 hours!

 This afternoon’s walk was another pleasant one due to still pretty dry air (dewpoints mid 30s), blue skies, and light winds though it was ~20 warmer (60 vs 40). So, though it was pleasant, it felt better and more invigorating yesterday.

 Natural gas is down still another 3% today making it a total of a whopping 29% just since the high of Dec 4th!

30 minutes ago, wncsnow said:

I don't even have an account on there. 

7 minutes ago, BooneWX said:

You don’t have to. I peak over there to cross check the vibes and today is a hilarious war of words. That’s why I stick here. Everything is measured and while they have some great posters, it’s full of too many folks speaking in absolutes and getting obnoxious when the ball doesn’t roll their way. 
 

I go here to converse, read anything from @Carvers Gapto learn, and head there for my entertainment.

 The two forums are very intertwined between many (probably a majority) of its members also being members and former posters here as well as some currently posting at both (in some cases with different names). I’m sure many read both boards daily.

1 hour ago, BooneWX said:

It is what it is at this point. We won’t be the only ones suffering. Best advice I’ve got is for everyone to take a deep breath at the keyboard, go outside, smell some Christmas trees, golf, fish, get some vitamin d. It’s been a cold 3 weeks and a break won’t be bad. I hope it’s not extended but what can any of us do about it? Jammin January and Fab Feb are just around the corner. 

 For me it wouldn’t be “suffering”. It isn’t anything like, say, bad health/getting sick. “Suffering” is too harsh a word from my standpoint even though it’s not at all what I prefer as I want it colder than normal at any point in the year. The good thing is that it’s my favorite season of the year and warmer than normal in winter is still much colder than, say, below normal in summer. In addition, this warmer period will be following one of the coldest 3 week periods from Thanksgiving through the first 17 or so days of December I’ve ever experienced and easily the coldest since 2010.

 Even if it’s going to be mild for awhile, forecast discussions would still be interesting in the most volatile season of all, winter.

6 minutes ago, 40/70 Benchmark said:

Does anyone have the link to the historical ERA5 10hPa 60N zonal wind data? For some reason my link no longer takes me to it....

Ray,

 If you mean the link to the site that produces the graphs of 10 hPa/60N mean zonal wind back to 1978-9, those could be produced by going in here:

https://acd-ext.gsfc.nasa.gov/Data_services/met/ann_data.html#ncep_clim_stats_nh

7 minutes ago, JenkinsJinkies said:

Also 16-17, 22-23 had no measurable December snow in the DC and Baltimore area airports. Very much not the case this year.

Also, Dec of 2016 had a +WPO and Dec of 2022 had a neutral WPO unlike the -WPO of Dec of 2025 fwiw.

 Our airport had a low of 25 for the 2nd morning in a row. My lowest was likely ~30 vs 26.6 yesterday. But the freeze last night was radiational rather than advective/windy with a much longer duration of ~9 hours.

1 hour ago, 40/70 Benchmark said:

All 6 of those seasons finished with a mean DM -WPO, so this season should, too....though we could have a month or two average +WPO, as was the case in 1990. Looks like I am going to be off on the WPO again...it's so tough to forecast. At least I didn't go strongly positive....

57 minutes ago, EastonSN+ said:

3 good and 3 bad winters snowfall wise. Nice even split.

 Thanks. That’s based on my 1st list, which is of those Decembers that had 1+ days dipping lower than -3.48. But those Decembers didn’t necessarily have a solid -WPO dominating through the entire month. One of those Decembers, 1996, actually averaged a +WPO overall. Also, 1983 and 1977 didn’t average a negative enough WPO. And there were a bunch of Decs left out of that 1st list that had a very -WPO with it dominating throughout but that didn’t have at least one day dip below -3.48 like 2013, 2010, 2009, 1995, 1980, 1961, and 1956 that make them good -WPO Dec analogs.

 OTOH, the 2nd list included some that weren’t -ENSO through the winter or at all like 2009, 1989, 1980, and 1956. In addition, 2005 and 1995 had a moderate or strong +PNA in Dec.

 So, what are we left with for the best analogs based on solid -WPO throughout Dec, -ENSO through the winter, and a moderate to strong -PNA in Dec? 2013, 2010, and 1961. Of these three, the PNA flipped to positive in Jan in 2014 and 2011 and to neutral in Jan of 1962.

  So, the closest -ENSO/Dec -WPO/Dec -PNA analogs are 2013, 2010, and 1961.

1 hour ago, BlizzardWx said:

I've been trying to think about what is "going wrong" with such a prolific -WPO to be talking about record warmth down my way. Do you know if a -WPO is typically good for the southern Plains? Is it perhaps atypical to have a -WPO paired with a -PNA or is that typical? I know when I look at the current pattern it seems reasonable to have a west coast trough downstream of that high but maybe sometimes ridging extends further southeast? 

Mostly just trying to build my understanding for this index. 

 I’ll check now for December. These 9 were solidly -WPO Decembers dominating throughout the entire month:

2013, 2010, 2009, 2005, 1995, 1989, 1980, 1961, and 1956. Of these:

1) Cold in the S Plains?

2013, 2009, 2005, 1989, 1961

2) Near normal S Plains?

2010, 1995

3) Mild S Plains?

1980, 1956

 So, strong -WPO Decembers leaned somewhat to the cold side in the S Plains, but only 5 of 9 averaged cold. It looks like this year may end up averaging near normal based on a cold 1st half and mild 2nd half. But we’ll see.

PNA for these 9 Decembers:

2013: moderate -PNA

2010: strong -PNA

2009: weak +PNA

2005: strong +PNA

1995: moderate +PNA

1989: moderate +PNA

1980: weak -PNA

1961: strong -PNA

1956: weak -PNA

 So, PNA for these solidly -WPO Decembers is very mixed.

 Well, as of Dec 13th, the MJO still hasn’t returned to phase 8! It was in 8 only Dec 3rd-7th. Dec 8th-13th have all been in very weak (essentially neutral) phases 5-7. I still think it has a good chance to get back into 8 very soon, but we’ll see:

 The 12/13/25 WPO of -3.48 is the most negative WPO on any day in December since 12/25/1996!

 The only Decembers since 1948 with at least one day lower than -3.48 are:

1996, 1989, 1983, 1977, 1966, 1955