GaWx

Strong SPV during cold and snow Nashville since 79: -Jans of 25, 22, 16, 00, 96, 84…so, 6 of 14 cold and snowy Jans had strong SPV (00 cold/snow last half of Jan) -Feb of 96

Todays Euro Weeklies are looking better/pretty good for 1/12-2/1. See the main ENSO thread for maps/more details if interested.

I’ll add that today’s weeklies have a stronger -NAO/-AO forming for 1/12-2/1: 1/12-18: 1/26-2/1:

Today’s Euro Weeklies are similar to the prior ones through Jan 11th with mild for much of the country though the warmest is closer to the C US, well away from the E US. However, today’s weeks 4-5 continue yesterday’s cooling trend: 1/12-18 12/17 run: 12/19 run: 1/19-25 12/18 run: 12/19 run: And then week 6 is similar to yesterday’s in the E US: In summary, whereas the first 3 weeks (through 1/11) remain mild in much of the E US, the last 3 weeks (1/12-2/1) are mainly NN to a little BN in most of the E US with nothing even resembling warmth. The 1/19-25 map suggests a +PNA is trying to form:

The 12Z GFS has 6 days of the rest of Dec having a high of 70+ at KATL (12/24-29): 70, 73, 72, 70, 71, and 73. Granted, 2 of the 6 days on this barely make 70. So, getting 6 won’t be easy. Many models including earlier GFS runs don’t have 70+ on 12/29 with the 5 of 12/24-28 more common for the most. That being said, IF it were to actually occur, 6 days of 70+ at KATL within 12/20+ would obviously be a very impressive anomaly! How rare would that actually be? Extremely! It’s only occurred three times since 1878: -2021 (warmest 75) -2015 (warmest 77) -1984 (warmest 74) Needless to say, this will be very interesting to follow!

The 12Z GFS has 6 days of the rest of Dec having a high of 70+ at KATL (12/24-29): 70, 73, 72, 70, 71, and 73. Granted, 2 of the 6 days on this barely make 70. So, getting 6 won’t be easy. Many models including earlier GFS runs don’t have 70+ on 12/29 with the 5 of 12/24-28 more common for the most. That being said, IF it were to actually occur, 6 days of 70+ at KATL within 12/20+ would obviously be a very impressive anomaly! How rare would that actually be? Extremely! It’s only occurred three times since 1878: -2021 (warmest 75) -2015 (warmest 77) -1984 (warmest 74) Needless to say, this will be very interesting to follow!

As I just posted, this time a year ago had a much colder weeks 3-4 outlook than now. But I also said that a somewhat better comparison might be how it looked for Jan 2022 at this time, when instead of one of the coldest week 3-4 outlooks on record for the SE half of the US, it was suggesting a mild SE half of the US (including Mid-Atlantic) was a better possibility: A little after this point in Dec of 2021, when there was a similar very strong -PNA to what’s being forecasted for late Dec, the weeks 3-4 outlook was far different than it was in 2024: How did Jan 8-21, 2022 verify in Greensboro, NC? They ended up 4 BELOW normal and had two 1”+ snowfalls. So, one would have had no clue from NOAA even as late as Dec 24th that a cold Jan of 2022 in much of the E US was incoming.

I agree that this is nothing like how Jan, 2025 was looking at this point in Dec of 2024, when the Euro Weeklies were much colder and this was the NOAA weeks 3-4 outlook, one of the coldest on record for the SE half of the US: AAM forecast had this then: Current AAM forecast: A somewhat better comparison might be this time in Dec of 2021, when there was a similarly very strong -PNA, Christmas was looking very warm, and there were still no strong hints on the 2 week guidance that a huge change was on the way although some CFS runs were cold in part of Jan.

Well, I just added something to my last post that may cheer you up. The models are actually suggesting a good chance this moved right back into 8 either yesterday or today! So, we might go right back to celebrating as early as tomorrow!

Talk about a turnaround! After one day of glee and bigtime celebration due to our immense accomplishment of getting phase 8 back, it’s already gone. The MJO moved into phase 7 two days ago. Turn out the lights, the party’s over (well as of two days ago at least). But the good news is that the models are suggesting a good chance this moved right back into 8 either yesterday or today! So, we might go right back to celebrating as early as tomorrow!

Todays Euro Weeklies are still not great by any means but they are a bit colder/less mild during 3 weeks of the 4 weeks starting with week 2: 12/29-1/4 yesterday 12/29-1/4 today 1/12-18 yesterday 1/12-18 today 1/5-11 was also a little colder today **Edited for corrections needed in my captioning because I had “today” and “yesterday” reversed. Today’s are less mild as I said.

I have it by luck on my phone as I happened to start saving a few in Dec of 2021 and Jan of 2022 I think because of long range hints on the CFS (of all models, which I also saved a bunch of…so kudos to the CFS then!) starting to show very long range big colder changes in late Dec and especially Jan. Since then, I happened to have saved a lot near and after the 2/16/2023 SSWE, which showed that the -NAO/-AO were initially way underdone/missed. Since then I’ve saved a bunch during the winters. I’m not aware of these being available to the public.

On 12/26/21, when the PNA had been negative all month/way down at -1.8 that day and Baltimore (among others) had just had a miserably mild 68F Christmas high with very mild to continue through New Year’s, this (see image below) was the 12/26/21 GEFS two week PNA forecast, which went to 1/9/22: still down at -0.6 on 1/9/22 and no clearcut sign that 1/9/22 was going to be the start of a 38 day long +PNA as well as Jan ending up the snowiest month by far there since Jan of 2016 along with it being the coldest month since Jan of 2018: @donsutherland1 *Edit: The main points are: - The models can’t see out that far with notable skill and that includes forecasting the PNA/general patterns - -ENSO -PNA Decembers since 1984 all transitioned to +PNA Jans

-Actually, Dec of 1996, indeed, was still another -ENSO strong -PNA that transitioned to a +PNA in Jan after a 1.8+ rise. -Dec of 1999 had a neutral PNA. So, that isn’t in this group. *Corrected for typo…Dec of 1999

I’m very curious to see what happens in Jan with the PNA based on -ENSO strong Dec -PNA analogs like 2021, 2013, 2010, 2008, and 1984 whose Jan PNA all rose 1.8++ from Dec. That’s still well beyond what models can see with any notable degree of skill. My GEFS PNA forecasting images for Dec 2021-Jan 2022 displayed that well.