GaWx

Per Joe D’Aleo at WB: “Strat warm favored in west QBO near solar max” I checked it and by golly I think he has a point: Solar DJF 135+/west QBO: 57-8: SSW 1/31/58 59-60: SSW 1/17/60 69-70: SSW 1/2/70 78-9: SSW 2/22/79 80-1: SSW 2/6/81 90-1: no SSW 99-00: SSW 3/20/00 01-02: SSW 12/31/01, 2/18/02 -So, of these 8 high solar/+QBO winters, 7 had at least one major SSW and one had two! - earliest 12/31 - 3 in Jan - 3 in Feb - 1 in Mar - So, perhaps one will actually be likely this winter should DJF SSN be 135+. SSN: https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt

The very next WB CFS ens run (12Z) map for the same period was ~25F warmer at Chicago, Great Falls and Madison and was ~23 warmer at Indianapolis:

Thanks, Mitch. I’m curious. Why is just a weakened PV better than (major) SSW? I know they haven’t all resulted in a cold E US within a few weeks afterward. But a decent number have done that, some impressively so. They may do better though when we don’t have a preexisting strong -PNA/strong SE ridge. That muted and shortened the cooling from the mid Feb of 2023 major SSW even though we in the SE got a chilly week in early to mid Mar (coldest in quite awhile).

The 12Z WB CFS ens mean temps are not surprisingly much warmer than the 6Z WB CFS for 1/9-15 even though it is still pretty cold in a smaller area 6Z: Chicago ~25 BN 12Z: Chicago ~5 BN

I’ve been focusing on temps. However, I’m also leaning toward WB CFS H5 runs averaging too low. I’ve seen numerous WB CFS H5 maps with blue colors dominating the hemisphere, which isn’t realistic in a warming world since avg H5 is also rising. Regardless, BAMwx cherry picked a very cold CFS ens late in the run, which is my point.

The model consensus, especially Euro, seems to be getting colder again for ~Dec 12th.

Thanks! Indeed, I counted only 5 major SSWs during 13 -ENSO/+QBO winters since 1957-8, with all interestingly enough only since 1999-00 and with 2 of these during 2001-2. The other 3 were during 1999-00, 2008-9, and 2022-3. So, just since 1999-00, there have been 5 major SSWs during 8 -ENSO/+QBO winters though there was only one during the last 5. How was solar for these 5 major SSWs? March of 2000: SSN 217 (near peak) Dec of 2001: SSN 213 (near peak) Feb of 2002: SSN 170 (just past peak) Jan of 2009: SSN 1 (minimum) Feb of 2023: SSN 111 (active but not near peak) Based on this data I see no negative correlation between SSN and chance of a major SSW during -ENSO/W QBO. The first 5 -ENSO/+QBO winters had none and only one of the last 5 had one. Four out of the 5 major SSWs were during 3 -ENSO/+QBO winters in a row! I agree that the likelihood isn’t good, especially one as early as ~12/24. But there’s still a nontrivial chance at some point this winter imho. Also, solar max doesn’t appear to lower those chances. Look at the SSNs I just compiled. I realize there seems to be an inverse relationship between SSN and -NAO winter as I’ve noted. But that’s not the same thing. The 13 -ENSO/+QBO (at 30 mb) winters since 1957-8 were 1961-2, 1966-7, 1971-2, 1975-6, 1985-6, 1999-00, 2001-2, 2008-9, 2010-1, 2013-4, 2016-7, 2020-1, and 2022-3. SSN: https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt QBO: https://psl.noaa.gov/data/correlation/qbo.data

Fwiw this is the weakest SPV Euro weeklies run yet for late Dec through Jan. I still wouldn’t call this “weak” but it is the weakest yet for then/weaker than avg. There are more members dipping rather sharply Dec 20-23 though there are still only 2 of 100 members (4%) with an actual wind reversal (major SSW) this month. I’ve learned based on the last couple of years that the models actually tend to be slow in catching onto major SSW events. With Dec 20th still being 15 days out, any possible major SSW then would probably be too far out for the bulk of members to see it though I’m by no means predicting one at this point: Edit: Looking back at records for La Niña or cold neutral with a W QBO and having a major SSW, the earliest in the season I could find was that of 12/31/2001. The second earliest is 1/24/2009.

Thanks for posting that. This tweet was posted elsewhere and here was my response to the bottom portion that addresses the extremely unreliable late portion of the cherry picked WB 6Z CFS ens mean: “I’d be cautious with WeatherBell CFS maps as they are usually colder than the NOAA and other versions. Also, one run of the CFS ensemble (4 members) like is being shown here (6Z of today) is extremely low in reliability, especially for the period near the end of the run. They jump around a lot. BAMwx shouldn’t imo be showing something like this as it borders on hype. They said ‘The CFS weekly is on board as well with a monster Alaskan ridge stretching well up into the pole. (-EPO)’ as if it were a big deal. But they cherry picked an extra cold run of the very jumpy, unreliable CFS and a WB version (colder than other versions) of it to boot. Don’t get me wrong. I’d love nothing more than for something like this to actually occur. But I don’t like to see hype.” Here’s the insanely ridiculously unrealistic and highly flawed WB 2m temperature anomaly map for this 6Z CFS ens mean for Jan 9-15: -10 to -30F anomalies (also note the typical WB CFS relative warm spot in N Michigan that’s indicative of a WB CFS flaw)

Mitch, Here’s the new WB Euro ensemble mean at H5 for Jan: looks like typical Nina with Aleutian ridge, BN hts far N Plains/Rockies/extreme upper MW, hints of SE ridge:

In contrast to the above BAMwx tweet showing the extreme -EPO of the WB 6Z CFS ensemble mean, here’s the average of the last 12 CFS ensemble means at Tropical Tidbits for Jan 9-15 (caution still advised as it is for 5 weeks out and it is the CFS): still a decent -EPO but much more subdued than the WB 6Z CFS ens mean (531 dm at MN/Canada border): Now check out the accompanying TT 2m temperature anomaly map: nothing extraordinary at all in the US with NN to slightly BN in the upper Midwest Compare the above to the WB 6Z CFS ens that BAMwx just tweeted (just one run and WB version) mean for Jan 9-15: this would border on historic for much of the US, especially Midwest (516 dm at MN/Canada border): And the accompanying WB 6Z CFS ens mean of today 2m temperature anomaly map has insanely ridiculous cold throughout most of the US (10-30F BN lmao) with nearly -30F in the upper Midwest (note the everpresent cold spot near Chicago and relative warm spot N Lake Michigan/Michigan indicative of flawed WB CFS maps):

The bottom portion of the following tweet from BAMwx (referring to today’s four member 6Z WB CFS ensemble) is imho borderline hype. Going back a few years, BAMwx tended to overhype at times. I hope they’re not reverting back. Someone just posted this tweet in the SE subforum and here was my reply: “I’d be cautious with WeatherBell CFS maps as they are usually colder than the NOAA and other versions. Also, one run of the CFS ensemble (4 members) like is being shown here (6Z of today) is extremely low in reliability, especially for the period near the end of the run. They jump around a lot. BAMwx shouldn’t imo be showing something like this as it borders on hype. They said “The CFS weekly is on board as well with a monster Alaskan ridge stretching well up into the pole. (-EPO)” as if it were a big deal. But they cherry picked an extra cold run of the very jumpy, unreliable CFS and a WB version (colder than other versions) of it to boot. Don’t get me wrong. I’d love nothing more than for something like this to actually occur. But I don’t like to see hype.”

I’d be cautious with WeatherBell CFS maps as they are usually colder than the NOAA and other versions. Also, one run of the CFS ensemble (4 members) like is being shown here (6Z of today) is extremely low in reliability, especially for the period near the end of the run. They jump around a lot. BAMwx shouldn’t imo be showing something like this as it borders on hype. They said “The CFS weekly is on board as well with a monster Alaskan ridge stretching well up into the pole. (-EPO)” as if it were a big deal. But they cherry picked an extra cold run of the very jumpy, unreliable CFS and a WB version (colder than other versions) of it to boot. Don’t get me wrong. I’d love nothing more than for something like this to actually occur. But I don’t like to see hype.

Latest WB Euro for Jan (12/1 forecast) is similar in New England, slightly warmer mid-Atlantic/SE (+2.5F to 3.5F), and cooler Midwest vs prior (11/1): Latest: Prior:

This is from pro-met Brad’s email response: “Your ideas about model biases are generally true. The CAN EN (GEPS) is often cold biased, and this is especially the case in the West as you have noted. The GEFS is often cold-biased as well, but this has not been the case more recently. I think the maps and graph from DTN make sense from what I remember this fall. With that said, model performance in the fall can vary more than other times of year. This might be a function of tropical activity, which peaks in the fall, but also the changing of seasons itself. So in that respect, I probably wouldn't consider the biases from this past fall to be an indication of how models will perform going forward.” “While I can’t say for sure what caused models to be too warm this fall season, their handling of soil moisture might be a theory:” So, in other words, Brad is suggesting that we not count on the net warm EPS/GEFS E US day 6-15 model biases of this past autumn continuing into this winter.

My opinion on this: -Michael Clark clearly presents his thoughts in detail with solid reasoning, especially regarding the MJO and TPV. Well done. He’s hinting at a strong possibility of a cold Jan in the Midwest to interior NE though he didn’t know about the coastal NE and said (virtually) nothing about the SE. -Per his history, I don’t put him in the Bastardi category of being a strongly cold biased hypester by any means (exhibited by him talking about warmth Dec 10-25/30….Bastardi would unlike Michael gloss over the warmth and skip to the cold potential)..so a big positive vs JB -Per that same history though, my feel is that he’s probably still a bit cold biased though not as much as a few years ago when I first followed him. -My biggest disappointment is how much emphasis he puts on the typically highly unreliable CFS. He focuses on the 12/4/24 0Z CFS 4 member ensemble run. Although that’s much better than just showing a control run (something JB often does when it is very cold), it’s still highly unreliable. -Besides it being typically highly unreliable, the CFS (though it has backed away slightly) is still calling for a record rate of Nino 3.4 cooling of -0.8C from Nov to Dec to -1.0C and then -1.25C in Jan! No other model is anywhere close. That potential huge error makes me wonder if it is affecting the CFS in Jan. -I also don’t like to see his displaying WxBell CFS US 2 meter temperature maps. They’re usually several degrees colder than what the NOAA CFS maps show on avg in the E US and are messed up. He showed the very cold WB 12/4/24 0Z ensemble run for Jan, which is almost definitely colder than what that actual CFS run has. Also, the maps he showed had the ever-present cold spot in S Lake Michigan and warm spot in N Lake Michigan. -My overall feeling is to take this with a grain but hope he’s generally right for Jan and hope that the cold includes the SE/Mid-Atlantic/coastal NE with no blocking mean SE ridge.

So, I want to make sure that Webb, jconsor and Chris are on the same page. Jconsor said this based on what Webb said: “Per Eric Webb, the PDO has limited influence and limited usefulness for subseasonal predictability (especially in a winter like this with a strong Indo-W Pacific warm pool).” This is what Webb said: “Most people misunderstand the direction of forcing. Extratropical SSTs are mostly forced by atmospheric circulation anomalies, not the other way around. I.e. the -PDO’s contemporary correlation with things like the -PNA is more of a reflection of the -PNA pattern forcing the -PDO on interannual scales, not the other way around” Chris, do you agree with jconsor and Webb that the PDO actually has limited influence on the atmosphere? So, does this mean that the record -PDO we’ve been having, itself, has been having only minimal impact on the atmosphere? There seems to be a lot of disagreement about this among the meteorological community, which has been confusing to me over the last few years. I‘m just trying to learn. For example, I used to think that -PDO, itself, including the W Pacific marine heatwave E of Japan, tended to help force a -PNA/stronger mean Aleutian ridge/stronger than avg mean SE ridge. But in reality it appears that the 15N to 15S warm pool in addition to La Niña is what drives that pattern and not also the marine heatwave to the north/-PDO. Chris and Yaakov, do I have this right? So, if so, does following the PDO, itself, have much usefulness for seasonal predictions for, say, the US and the Atlantic tropics? If not, what’s the point with regard to forecasting mean seasonal atmospheric circulation in following the PDO index and the E of Japan marine heatwave?

So, would you agree that the warm pool is between 15N and 15S latitudinal range? I want to make sure I’m properly following along with you on the waters you’re focusing on. So, does this mean that the marine heatwave E of Japan is having minimal impact on the atmosphere?

-RONI for SON just came out at -0.80. So, on a RONI basis this event will end up with at least a solid weak La Niña peak. -ONI for SON: -0.24 -So, difference between RONI and ONI in SON was -0.56 (difference between -0.80 and -0.24) - Difference between RONI and ONI: MJJ: -0.60 JJA: -0.55 JAS: -0.52 ASO: -0.54 SON: -0.56 So, when I see an OISST and want to very roughly estimate the equivalent daily RONI, I’m currently subtracting ~0.55. The Dec. 1st OISST was -0.35. So, I have the current equivalent Dec 1st RONI near -0.90**(**Corrected for typo).

The record high is +15.62 (June of 1995). I give it about a 10% chance to be exceeded. If so, that would almost definitely be in Dec or Jan.

-Nov QBO (at 30 mb): came in at +13.78 (about as expected) vs Oct’s +11.64. -Based on historical patterns (back to 1947 on this table), either Nov or more than likely Dec will be the peak. Jan has only a very small shot to be the month of the highest as it will likely already be starting to fall then. Peak almost definitely to be from +13.78 to +15.6 with best guess in the +14s: https://psl.noaa.gov/data/correlation/qbo.data We very likely will have a solid -QBO next winter.

Lows in my area: coldest of season to date KSAV 27 KSVN 28 Some others: KATL 27 coldest of season KGNV 26! @pcbjr had the coldest of these four locations and coldest for Hogtown to date this season. Radiation capital of the deep SE!

I just took a walk in 33-34 temperatures. But I was dressed appropriately and the winds were calm. So, I enjoyed it! It was so peaceful with it too cold for others.

Thanks, Chris. Honestly, I’m still surprised to see there being so much EPS warm bias over the E US in the 6-15 over the last 90 days. It is even showing warm bias over the Great Lakes, where the mean ridge axis was:

Interesting! The DTN bias graphs for GEFS/EPS you linked me for days 6-15 averaged over the last 90 days are surprisingly showing a warm bias in the NE US. I wonder why. If I get a chance, I’m going to email my Maxar pro met contact. Maybe he can give me an update on the week 2 biases.