GaWx

12Z EPS held into the cold partially because of this:

For Dec 1-10: 12Z EPS held onto its 0Z significantly colder temps vs 0Z GEFS. But also, 12Z GEFS came in significantly colder than 0Z GEFS: 0Z GEFS: 12Z GEFS: colder/in EPS direction: 12Z GEPS came in much colder than 0Z GEPS: 0Z GEPS: 12Z GEPS: colder than 0Z GEPS Edit: NG is up 7% on the colder model consensus.

12Z GEFS is coming in significantly colder than the 0Z for week 2:

Indeed, after doing poorly with phase 6, the EPS absolutely was doing much better than GEFS getting into phase 7 between the 11/15 and 11/18 runs: 11/15 EPS: poor for 6; much better for getting into 7 11/15 GEFS: great for 6 but bad for getting into 7 (way too slow as 7 actually started on 11/27): Similar comparisons for 11/17-8 runs: 11/17 EPS: almost spot on with 11/27 ph 7 timing: 11/17 GEFS: still not in 7 on 12/1 11/18 EPS: great with ph 7 11/18 GEFS: not into phase 7 til 12/2, 5 days too late Edit: 12Z GEFS coming in significantly colder than prior runs

Related to this, check out the differences in the means (green) between the +AO of the 0Z GEFS and the slight -AO of the EPS: GEFS: EPS:

With the unfavorable changes in the MJO and AO/NAO, today’s 0Z GEFS is not surprisingly significantly warmer than yesterday’s run for the 2nd week in Dec. However, today’s 0Z EPS, which maintained its very long phase 8, is much colder than yesterday as well as the GEFS: Yesterday’s 0Z EPS for 12/5-11 2m temps: Today’s 0Z EPS for 12/5-11: it’s pretty rare for a 7 day period of the EPS to have that much of a change within just 24 hours: As a result, the aggregate of today’s Euro Weeklies 12/1-7 and 12/8-14 2m temp anomaly maps will very likely be notably colder than yesterday’s.

MJO: Yesterday’s EPS: Edit: Adding yesterday’s ext-EPS: record shattering 26 day phase 8 Dec 3-28 (current record 18 days)! Today’s EPS excellent consistency with yesterday with a very long (10+ day) long phase 8: Yesterday’s GEFS: Today’s GEFS hopefully this is off as it went from yesterday’s similar to Euro very long phase 8 to no phase 8 through at least Dec 12th: In summary, mixed results today: fantastic EPS and not so good GEFS. Hoping with the aid of the current major SSW that the EPS will end up the winner for today’s runs!

It may be Twitter bait. But that’s not because they don’t go out far enough. Rather, it’s that that this Tweet’s runs are “bias corrected” versions, which have more often than not not been making the correct adjustments based on my following them. Here are the corresponding non-bc versions, which are very bullish for phase 8 within their runs: 11/26 ext GEFS: 8 day long phase 8 mid Dec (12/13-20) with a potential 2nd move into phase 8 a few days after this ends: 11/26 ext EPS: extremely bullish 15 day long phase 8 (12/13-27), which would be 2nd longest of all time on record for any month:

I agree 100% about the realistic possibility that the models have been slow to react to a more -AO/-NAO as potential effects of the current SSWE. Why? I have to look no further back than the 2/16/2023 major SSW. Even on the run of the day of the actual strat. reversal the GEFS was still clueless about the impending drop of the NAO late Feb into mid March: 2/16/23 (day of SSWE) GEFS NAO forecast through 3/2/23 was dead neutral (0) through 3/2/23: Actual daily NAOs: look how the GEFS run from the day of the SSWE was way too positive for Feb 26th-Mar 2nd! 2023 2 16 0.918 2023 2 17 1.051 2023 2 18 1.202 2023 2 19 1.122 2023 2 20 0.775 2023 2 21 0.480 2023 2 22 0.330 2023 2 23 0.157 2023 2 24 0.155 2023 2 25 0.047 2023 2 26 -0.301 2023 2 27 -0.742 2023 2 28 -0.748 2023 3 1 -0.956 2023 3 2 -1.006 2023 3 3 -1.093 2023 3 4 -1.161 2023 3 5 -1.109 2023 3 6 -1.132 2023 3 7 -1.187 2023 3 8 -1.091 2023 3 9 -0.614 2023 3 10 -0.356 2023 3 11 -0.293 2023 3 12 -0.254 The next day and the following days, the GEFS started catching on and had this just 4 days later (2/20/23), which was much closer to what actually happened: this was through Mar 6th: Similar trends happened with the AO. The moral of this real-life story? Stay tuned for more potential big NAO/AO drops for mid December! Daily NAO: https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.index.b500101.current.ascii @donsutherland1

And here’s even more good trends vs yesterday for cold lovers: Yesterday’s (11/26) GEFS AO through 12/10: rose to solid +AO of +1: Today’s (11/27) GEFS AO: neutral/near 0:

If the more favorable phase 8 progs today vs yesterday are not enough good news for those who prefer it cold in the E US, I’ve got more: Yesterday’s (11/26) GEFS NAO through 12/10: headed to moderate +NAO Today’s (11/27) GEFS NAO through 12/11: no +NAO as it stops rising at dead neutral (0):

Yesterday’s (11/26) 2 week EPS (through 12/10): barely made it to phase 8 on Dec 5th-6th before circling back to phase 7 (extended showed it made it back to phase 8 12/13-27+): Today’s (11/27) 2 week EPS through 12/11: gets to phase 8 on 12/3 and stays through the end of the run (12/11), meaning a 9+ day long phase 8, which would be the longest Dec phase 8 at least since the 10 day long phase 8 of 1989: (tomorrow’s ext EPS will show the total length) In summary, all GEFS/EPS MJO forecasts are more favorable with regard to phase 8 vs what was available yesterday (2 week and extended). Both of today’s 2 week forecasts (GEFS and EPS) have phase 8 Dec 3-11+.

Yesterday’s (11/26) 2 week GEFS (through 12/10): didn’t make it to phase 8 (extended showed it made it but not til 12/13): Today’s (11/27) 2 week GEFS through 12/11: already makes it to phase 8 on 12/3, which is TEN days earlier than yesterday. It remains in phase 8 through the end, meaning it would be a 9+ day phase 8, the longest Dec phase 8 since 1989:

Yesterday’s (11/26) EPS 2 week MJO forecast through Dec 10th: was then curling back away from 8 after barely getting into it and we were wondering whether it would ever get back to phase 8: Yesterday’s (11/26) EPS extended, which adds 12/11-27: had a 15+ day phase 8 12/13-27, which would be the 2nd longest phase 8 on record for any month (2nd only to the 18 day long phase 8 of Dec-Jan 1975-6) and the more favorable for cold weak to moderate amp (vs strong) to boot:

Yesterday’s (11/26) GEFS 2 week through 12/10: was then curling back away from 8 and we were wondering whether it would ever make phase 8: Yesterday’s (11/26) GEFS extended, which adds 12/11-12/27: it turned out that it made phase 8 for an 8 day period (12/13-20), which would be longest phase 8 since Feb of 2019’s 9 day long ph 8 and the longest Dec ph 8 since Dec of 1989’s 10 day long ph 8 along with it being a more favorable for cold weak to moderate amp: