GaWx

2 hours ago, PhiEaglesfan712 said:

After that, do you think the winter returns, or are we going to torch in January and February, like in 2016-17 and 2022-23?

 Or will Jan be cold like in 1984, 1985, 2009, 2011, 2014, and 2022?

Or will Jan be within a few degrees of normal (in the NE at least) like 1997, 1999, and 2013?

 So, Jan has had 3 times as many cold vs warm for the analogs since 1983-4 that I’m looking at.

 OTOH, Feb has a better chance to torch in the NE imho as only 2014 of the analogs I’m looking at was solidly cold there vs 6 being cold in Jan. In Feb, these were mild: 1984, 1997, 1999, 2009, 2017, and 2023.

 So, in Feb, 6 times as many were mild vs cold. That compares to 3 times as many cold vs mild in Jan. Two very different months on average.

 I just took an invigorating walk at the park with middle to low 40s, dewpoints in the high 30s, and no more than a light breeze. This is close to ideal walking wx for me…well except for having the extremely rare snow on the ground to walk on. Nothing beats the soothing feeling of walking on snow!

2 hours ago, donsutherland1 said:

There's an ERA-5 dataset that goes back to 1940. 

https://www.psl.noaa.gov/mjo/mjoindex/omi.era5.1x.webpage.4023.txt

 Thanks, Don.
 

 Just to make sure there’s no confusion of the viewers, these ERA-5 values do not match the BoM RMM values. So, they aren’t substitutes for each other as they’re not the same way of tracking the MJO. Examples:

- The end of the ERA-5 is on 8/31/2023. Here are the values on 8/25-31/2023 from both the ERA-5 and the BoM RMM:

8/25: ERA-5 is in ph 7 at 1.1 amp

8/25: BoM is in ph 8 at 0.84 amp

8/26: ERA-5 is in ph 7 at 1.06 amp

8/26: BoM is in ph 8 at 0.85 amp

8/27: ERA-5 is in ph 7 at 0.97 amp

8/27: BoM is in ph 1 at 0.64 amp

8/28: ERA-5 is in ph 7 at 0.83 amp

8/28: BoM is in ph 2 at 0.46 amp

8/29: ERA-5 is in ph 7 at 0.66 amp

8/29: BoM is in ph 2 at 0.27 amp

8/30: ERA-5 is in ph 7 at 0.46 amp

8/30: BoM is in ph 3 at 0.28 amp

8/31: ERA-5 is in ph 7 at 0.24 amp

8/31: BoM is in ph 3 at 0.26 amp

ERA-5 MJO 1/2/1940-8/31/2023

https://www.psl.noaa.gov/mjo/mjoindex/omi.era5.1x.webpage.4023.txt
 

BoM RMM MJO 6/1/1974-present

https://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

 I’m assuming this Euro Weeklies H5 has a good chance to verify way off in the E US considering the projected MJO as well as PNA analogs that suggest a +PNA would be likely in Jan and also that the Euro has been correcting for a too strong SER recently:

IF these were to be close to reality, they’d open the door for frigid air to plunge into the US ~12/18-21: MJO phase 8 would be supportive in Dec

12Z EPS: frigid MT/W ND N into SW Canada

12Z EPS: cross polar flow

 

12Z GEFS: frigid N MT/N Plains/MN northwestward into SW Canada:

12Z GEFS: cross polar flow

The 12Z EPS is hinting at a 3rd NC snow threat on 12/12 with measurable snow from 7 of the 50 members, mainly from lows that move just offshore:

The 12Z Euro has an off the coast low on 12/8 but it’s significantly too warm for snow per 850s/there’s no cold air connection at the surface and it’s actually dry over much of NC outside of far SE part of the state (it would need to get stronger for NC snow per this):

9 minutes ago, michsnowfreak said:

My area missed the brunt of the Nov 29 storm to the west and was just grazed by the storm that hit the east. But looks and feels like winter. We won't even touch freezing all week. Single digits Thu night. This is not normal early Dec weather. Avg highs in NYC are still upper 40s. Winter is just starting. Everyone wants a big storm but winter has more to offer than that.

It’s also a matter of perspective. To me that’s a lot of snow in your pic. This area has had that much snow or sleet in the entire winter only 3 times in the last 45 years (1/2025, 1/2018, and 12/1989) and could easily not see that much again for decades.

13 minutes ago, Newman said:

Does anyone know of anywhere that has MJO RMM plots before 1975? The Australia BOM archived site only goes back to 1975.

I’ve never seen any MJO history prior to the BoM’s 6/1/1974. 

 Natural gas is now near $5, which is the highest in nearly 4 years. NG generally is highest in winter when the E US, especially NE and Midwest, is forecasted to be colder than normal.

5 hours ago, BornAgain13 said:

0z GEFS just for the Monday system 

 

 
 For the twelve 6”+ RDU storms since MJO records started, here are the MJO phases with the largest # of these storms:

-3: 3.5 28.2”
-8: 2.5 16.8”
-5: 2 13.2”
-1: 1.5 23.7”
-7: 1 10.8”
-4: 1 5.9”
-2: 0.5 9.0”
-6: 0 0.0”

MJO amplitude:
Weak: 63.9” (on or inside circle)
Mod 37.8” (1-2 amp)
Strong 5.9” (2+ amp)

-The MJO is progged to be weak phase 8 Dec 8-9th

-All of the 6”+ RDU snows during phases 8, 1, and 2 were when the MJO was inside the circle.

-Phase 3 leading may seem counterintuitive but it’s not when considering that 3 of the 3.5 phase 3 storms were during Feb or Mar, when phase 3 is one of the coldest phases:

18 minutes ago, MJO812 said:

Models are getting active because of phase 8. Timing issues will be key moving forward. 

 Regardless, there’s been and looks to continue to be plenty of winter (cold and/or wintry precip) in most of the E US through the first half of Dec at least. Despite the weak -PNA, there’s a very rare combo of a very long moderate amp phase 8 MJO, a -NAO, and a -AO to more than compensate.

-NAO: wasn’t seen dominating the 1st 1/2 of Dec as recently as 5 days ago

-AO: wasn’t seen dominating the 1st 1/2 of Dec as recently as 5 days ago

 Today’s MJO forecasts:

1. EPS is once again very steady and has a 15+ day long phase 8, the longest winter phase 8 in 50 years: one couldn’t place it in a better position in Dec for the entire 2 weeks for E US cold lovers:

GEFS has been more jumpy than the EPS from day to day: today it still has a 9 day long phase 8, which itself would still be the longest in winter since Feb of 2019’s 9 days, before backtracking to phase 7:

2 hours ago, donsutherland1 said:

All said, I see little at this time to suggest that the base scenario of a PNA- December has grown less likely. The continued persistence of the guidance has, if anything, reinforced the base scenario of a predominant PNA- overall.

Hey Don,

 If a -PNA verifies for Dec, which is becoming increasingly likely as you’re implying, the chances for a +PNA in Jan are increased based on the last 11 -ENSO -PNA Decs all proceeding to a +PNA Jan. This includes Jans like 1985, 2011, 2014, and 2022. There was even some tendency for the strongest +PNA of these Januaries to follow the strongest -PNA of these Decembers.

Dec:

Jan:

Feb:

@EastonSN+PNA in Dec of 2008 was -1.41 and was +0.61 in the much colder Jan.

Holy Euro Barney!

50 minutes ago, JoshM said:

Damn... Happy hour is a little late 

It would seem quite possible considering the indices:

- rising -NAO
- rising -AO
- weak MJO phase 8 (near or inside circle)
- quick +PNA spike

 The Nov 30 mb QBO came out about as expected at -25.35, slightly lower than Oct’s -24.65:

https://psl.noaa.gov/data/correlation/qbo.data

 I just realized we don’t yet have a December 2025 thread. Please post about your own obs as well as about other current or recent wx from any location.

 Please pin this and unpin Nov @buckeyefan1. Thank you.

13 minutes ago, SnowGoose69 said:

I feel like since 2010 just about every December down there has been warm minus 2020/2024

Don’t forget 2022 and 2017, which were NN in the SE.

13 minutes ago, WinstonSalemArlington said:

Happy Hanukkah

These, especially the first map, are consistent with typical phase 8 MJO in the E US:

1 minute ago, SnowGoose69 said:

Down in the SE US Dec 2023 was not as warm as 2019.  2023 the warmth was worse across the Lakes/UW and NE

8 minutes ago, PhiEaglesfan712 said:

I assume you mean 2023, instead of 2019.

In the SE, Dec of 2019 in F was +2 to +5 vs Dec of 2023’s 0 to +3. So, 2019 was 2 warmer.

13 minutes ago, MJO812 said:

Weeklies

This is downright ugly for the SE 12/15-1/12 (ECMWF site, itself, is warmer than WxBell’s interpretation), but I’m hopeful it’s overdoing the SER like it has been recently. Plus, this period is still a near eternity away forecasting credibilitywise, especially holidays onward.

 The Euro Weeklies have a potent mean SER/-PNA Dec 15th-Jan 11th. Though the Weeklies have over forecasted the SER recently, it’s getting increasingly likely that Dec will average a -PNA. Since 1983-4, there have been 11 -ENSO winters with a -PNA. All 11 had a +PNA in the subsequent Jan. Based on this, the odds of a +PNA for Jan averaged out are increasing. If that were to verify, the chances would be high that the Euro’s potent -PNA Jan 1-11 will be wrong. We’ll see. 

12/15-21:

12/22-28:

12/29-1/4:

1/5-11:

Today’s MJO forecasts finally came out:

GEFS: Phase 8 12/2-16 (15 days+)

EPS: Phase 8 12/3-16 (14 days+)

 Should either of these progs verify, it would be the longest winter phase 8 in 50 years!

 The updated PDO (for 11/30) rose some more to -0.46 (from -0.51 on the prior day):