GaWx

Look at how much colder H5 on the Euro Weeklies is compared to yesterday’s: that’s a big change for a 30 day period! Yesterday’s: Today’s:

Regarding today’s Euro Weeklies, it’s the most bullish (i.e., colder changes vs prior run) overall in a long time in the NE and SE. I’m not saying they’re cold in the SE, but they are colder than they were/not as mild or not mild overall. I don’t have time to post details right now, but y’all check it out! Or someone else please post the maps. Edit: Every one of the 5 weeks is colder and/or less mild in both the NE and SE US vs yesterday’s run including one dramatically colder week. That hasn’t happened in quite awhile.

Hey John, Thanks for bringing up the amp. What you said generally coincides with my thoughts. But I’d like to clarify what I’ve said just to make sure there’s not a misunderstanding. Indeed, various analyses I’ve done over the last 10-11 years or so, which all have involved calculations of actual temperatures in a place or places in the E US, have shown that the average anomalies have tended to be colder with low to moderate amp (1.7 or lower in my latest study, which was 8+ day long phase 8s) vs strong AMO of phase 8. But not “essentially every low amp pass”. It’s more like a majority of low amp have been cold vs pretty balanced for high amp.

Today’s MJO through 12/10: tune in tomorrow to see what they’ll do 12/11-27:

So, now I can give you the answer Yesterday’s 2 week GEFS (through 12/9/25) was starting to loop in 7 through the end of the 2 week run: was it going to stay in 7 or was it going to go into 8? Here’s the much anticipated answer: it ended up doing just a small, quick loop in 7 but then it went a little ways into 8 on 12/11. But that little ways was enough for the moderate amped 8 to last 8 days (12/11-18), which alone would be enough for the longest Dec phase 8 since Dec of 1989’s 10 days and longest, period, since Feb of 2019’s 9 days. However, it then looped back into 7 a little ways 12/19-26 with it stalled at the end. Now my question is whether or not it would have gone back into 8: we’ll never know that far out on this run

The above noted colder GEFS trend for early Dec continued with the 12Z run.

That ext Euro phase 8 lasts 11 days, which would be the longest in Dec since 1975. I just hope it actually gets there and stays for awhile rather than curl back to 7 to stay.

1. No, ext for same run comes out a day later. —————— 2. GEFS 2 days ago: GEFS yesterday: gets to phase 8 five days earlier than any other GEFS as of then: GEFS today: curled back very slightly vs yesterday (E US cold lovers wouldn’t want a curl back into phase 7) but very similar to yesterday/look how different it is vs 2 days ago!

Yesterday’s Euro: phase 8 starts 12/14: Today’s Euro: phase 8 starts 10 days earlier, 12/4, (with a 6+day long phase 8 implied) although I’d want to make sure it isn’t curling back into 7 and staying there: last time Dec had a 6+ day long phase 8 was way back in 1995 (12/20-5):

Euro Weeklies 2m temps for 11/24-30 and this is before the very recent cooldown for early Dec: 11/17 run: 11/24 run:

The colder trend for early Dec is happening on all ensembles including GEFS: these are all for a week from today at 7PM: watch the SER disappear: @donsutherland1@bluewave

I’m wondering if despite the clear warming trend of the Euro Weeklies related to its insistence of a stubborn potent SER along with the current progged switch to a +AO if there’s lower than normal confidence due to a combo of the MJO taking a track that’s often cold (though far from always as we know) and the current very weak SPV, which typically takes 2+ weeks to bring the E US persistent dominating cold.

I didn’t pick up on this earlier and don’t know if anyone else posted this. Today’s GEFS has phase 8 starting on Dec 8th, which is about 5 days earlier than any other run:

Your post shows yesterday’s ext EPS predicting an 11 day long phase 8 for 12/14-24 averaging ~2.0 amplitude. The ext GFS is predicting a 12++ day long phase 8 for 12/13-24++ but with a much lower avg amp that with extrapolation would likely be headed to a sub 1.5 amp for the full phase 8 avg. Regarding the EPS prog, there hasn’t been an 11+ day phase 8 since back in Feb of 2010 (2/7-17). Regarding the GEFS prog of 12++ days, there hasn’t been a 12+ day long one since way back in Dec ‘75-Jan ‘76 (12/19-1/5)! There have been only two on record of 12+ days: the just mentioned one of 18 days and a 13 day long one 1/19-31/75. Also, the 15 long phase 8s (8+ days) have followed long phase 7s (9+ days) only twice out of the 15 cases although the two that did were two of the coldest. So, needless to say, I’m taking these very long phase 8 progs with a huge grain for now. Of the 15 long phase 8s at Baltimore, the ones averaging an amp of <1.8 (like GEFS has) were significantly colder in the E US on avg than those with an avg amp >1.8 (like EPS has). The GEFS-like sub 1.8 amp cases include the very cold outbreaks of Jan of 1985, Jan of 1988, Dec of 1989, and Feb of 2010 with 3+” snows (including historic snow in 2010) for all 4 in Baltimore for example. The other 3 sub 1.8 amp phase 8s had either BN (1) or NN (2) temps at Baltimore. So, even a GEFS-like moderate long phase 8 hasn’t always been cold at Baltimore but rather in most cases and with no mild cases. But half of the >1.8 amp long phase 8s were warmer than normal! So, if there’s actually a very long phase 8, I’ll be rooting for one closer to the lower amp of GEFS than the higher amp of EPS due to better prospects for cold per long phase 8 history.

There has been a +PNA in Jan for all 11 cold ENSO winters that had a -PNA in Dec since 1983-4: -1983-4: -0.31 to +0.97 -1984-5: -1.60 to +1.63 -1996-7: -1.23 to +0.63 -1998-9: -0.09 to +0.16 -2008-9: -1.41 to +0.61 -2010-11: -1.78 to +1.29 -2012-3: -1.01 to +0.55 -2013-4: -0.86 to +0.97 -2016-7: -0.35 to +0.28 -2021-2: -2.56 to +1.01 -2022-3: -0.66 to +0.22 ———— What kind of PNA are you expecting in Jan?