GaWx

After trending in the direction of increasing chance for midmonth major SSW the prior 3 days, today’s Euro Weeklies trended back the other way some. After yesterday’s +16 low for mid Feb, today’s only goes down to +20. This fits in with the GFS reversing course recently to a lowered chance. If there’s going to actually be one, a reversal of this reversal would be needed very soon.

Fwiw 1/31/25 CANSIPS is still calling for a Modoki El Niño forming in July but the signal is a little weaker. It’s been calling for this since the July 31st run! I know you’ve been insisting no El Nino til 2026. We’ll see I guess. CANSIPS could be out to lunch though I hope not.

Jan 2025 PDO rose to -1.32, which is the highest since Jan of 2023 and which compares to Dec’s -2.04, Nov’s -3.13, and Oct’s -3.80. Based on ~stalling since late Dec, the big rise may be done for awhile. @snowman19 2024 -1.57 -1.33 -1.52 -2.11 -2.98 -3.15 -3.00 -2.91 -3.56 -3.80 -3.13 -2.04 2025 -1.32

12Z EPS 10:1 24 hour snow: nice hit NW NC and big hit much of VA

12Z Euro is actually qpf wise for many here mainly a heavy rainstorm (with many temps getting well up into 40s to 50s/near 60) after a short period of snow and then a period of ZR Flooding from heavy rain could be the most noteworthy issue per Euro.

12Z Euro for 2/12-13 storm: light snow followed by moderate ZR followed by heavy rain (bulk of qpf rain) 12Z Euro Kuchera snow: 12Z Euro ZR (sleet very limited)

12Z GFS sleet: 12Z GFS ZR:

The last few GFS runs have reversed away from a mid-Feb major SSW (10 mb 60N zonal mean winds <0). For example, compare these two runs: 6Z 1/30 run: looked like a major SSW with an amazing split with SPV obliterated 6Z 2/3 run: doesn’t even look close to a major SSW This is a crucial period in the forecasting and will need to revert back in the major SSW direction very soon to keep hope alive for one. As it is, I’m very disappointed to see these last few GFS runs. Edit: 0Z Euro for same time: in between but closer to 6Z GFS and thus not even close to a major SSW

6Z GEFS: I count 7 of the 30 members with a widespread significant winter storm within 2/12-13 centered on much of NC/NW SC/NE GA. Many of these have a mix. In addition a few give far N NC snow within 2/10-11. Snowfall (10:1) mean that includes both periods:

In the interest of honest and open communication and to try to prevent any misinformation from being inadvertently spread, this is what I just posted in the La Niña thread after having just seen this here and initially being confused: —————— The following tweet from “Heinrich Leopold” (tweeted at 3AM today) was posted a little earlier in the SE forum. I haven’t replied yet and just responded with a “confused” reaction. Since then I figured out what the Arctic record lows are (the chart below with the red line). This almost has to be showing stratospheric record lows (quite possibly at 10 mb), which I’d fully believe as I was just noting current near record high 60N zonal mean winds of 61 m/s at 10 mb. Note his “natgas” tag by the way. I then saw this from him: https://x.com/LeopoldHeinrich It says he’s a chemical engineer rather than a met. This shows a lot of his tweets. I’ll let y’all read them and judge for yourselves. —————————— **So, to sum it up, there were nowhere near record Arctic low temps at the surface, which would make zero sense with Arctic ice near record lows as NorthHillsWx correctly stated very well. Instead, the record low temps are way up high in the strat over the N Pole, which has nothing to do with the surface. The Arctic surface temps are, indeed, WAY above normal! The warmup he’s referring to is a SSW of the record cold (for Feb 2nd) strat. But he communicated that in a very poor, misleading manner.

Don and others, The following tweet from “Heinrich Leopold” tweeted at 3AM today) was posted a little earlier in the SE forum. I haven’t replied yet and just responded with a “confused” reaction. Since then I figured out what the Arctic record lows are (the chart below with the red line). This almost has to be showing stratospheric record lows (quite possibly at 10 mb), which I’d fully believe as I was just noting current near record high 60N zonal mean winds of 61 m/s at 10 mb. Note his “natgas” tag by the way. I then saw this from him: https://x.com/LeopoldHeinrich It says he’s a chemical engineer rather than a met. This shows a lot of his tweets. I’ll let y’all read them and judge for yourselves. ——— Edit: I just replied in the SE forum about this being strat record low temps over the N Pole as opposed to record low surface temps in the Arctic. I mentioned that the warming (the red line) is a SSW of the record cold (for Feb 2nd) strat.

On Fri’s Euro Weeklies some of SE was as warm as 7AN for Feb (~normal for Mar). Today that warmest is only ~4AN with that all due to a warm 1st half. Today’s 2nd half has everyone N FL north near or slightly BN last half vs yesterday’s 2nd half being slightly AN everywhere.

Indeed! Colder changes are on par with some of biggest changes I can recall seeing in just 24 hours. Three of the 6 weeks (last half Feb to early Mar) changed greatly. The largest change was for Feb 17-23: Yesterday: Today:

Today’s Euro Weeklies 10 mb: still trending in direction of major SSW Feb 13-14: Today’s mean down to +16 then vs +22, +28 and +39 on three prior days’ runs Compare to run from just 3 days ago:

NW trend is pretty common in most cases not involving a massive Arctic outbreak when looking that far out due to cold bias of models. So, most know to expect that. Even the mountains may not be safe. That’s why seeing something that far out with a big winter storm is mainly for entertainment and should be taken with a huge grain. If it doesn’t trend NW from here, it would be a bit surprising.

Regarding the maps: I see WxBell as still being worth subscribing to because they do have lots of great maps. But it’s good to be aware that certain maps shouldn’t be taken as accurate. One of best examples: CFS 2m temperature anomalies. And now we can probably add NAO (WB and WxModels). There are very likely a good number of others, too.

I still love following the CPC based indices due to the invaluable daily history going back to 1950. That’s over 27K days! So, for me, CPC is gold standard, regardless.

There’s a huge difference between the WxBell and CPC 0Z GEFS based NAO forecasts when in theory they should be about the same. So, algo/definition diffs: @donsutherland1 WxBell 0Z Feb 2nd GEFS NAO: -2 on 2/14 CPC 0Z Feb 2nd GEFS NAO: +0.5 on 2/14

Regarding the S-G Dipole that Simon Lee did a study of soon after the 2/12/2018 major SSW due to the perceived connection, the models haven’t at all backed off on it for this week: By the way the S-G Dipole is by definition often associated with a strong +NAO. Note the forecasted strong +NAO (~+1.7) for late week:

Today’s 0Z GEFS based forecast has the AO dropping to -2 Feb 14-16 vs down to only -1 on Feb 14-15 on yesterday’s run. That is not directly related to any potential major SSW as those require a lag period from the SSW to get down into troposphere and it would be occurring at about the same time. Any direct downward effects from it wouldn’t be til late Feb into March. I’m anticipating big changes on some aspects/portions of today’s Euro Weeklies. We’ll see if that’s actually the case.

0Z GEFS mean based AO forecasts are often volatile. For midmonth they’re much lower today vs yesterday (not related to potential major SSW moving down into troposphere because there has to be lag after those to get there and this would be at ~same time): Yesterday: lowest -1 on 2/14-5 Today: lowest -2 on 2/14-6 I’m anticipating big changes on some aspects/portions of today’s Euro Weeklies. We’ll see if that’s actually the case.

0Z Euro: mainly for entertainment since hours 240-264 and very different from prior run: I kind of hope Brick doesn’t see this so as to prevent him from getting overly excited before bedtime; take with grain this very heavy snowstorm some areas; 0.1” snow just N of KATL…would be 3rd within 5 weeks for ATL area SE of I-85! Last winter KATL got 3 measurable events: 2010-11 and 2009-10. @dsaurtell the moles no sleet for them on this run and sleet only in few areas this run (not near you). So not posting it/trying to conserve attachment space lol. Nite nite!

Mainly for entertainment from 0Z GFS as it will almost certainly change a lot on the 6Z since this is so far out and it’s so different from the prior run:

Interestingly, 0Z GFS went toward the 18Z Euro AI to an extent with two consecutive CAD induced sleet and ice events in update SC and much of NC Feb 12-13. But we’re still talking 240+ hours out on the GFS. So, taking with a huge grain right now. It would probably be best to start looking at the ensembles for this period to get a better feel for whether or not this will likely be the next SE winter threat period.

How has the Euro AI done this winter compared to the major globals including the Euro op? I followed it closely for the 1/10-11 winter storm and thought that it was terrible with surface features. I posted about that several times with supporting maps. For example, remember the warming S winds it had going well inland into the SE despite the low being in the Gulf, something that almost never happens and didn’t. It had no wedge and instead it had the S flow ahead of a Clipper and on the backside of a high moving offshore. This is enough to tell me to not put much weight on it when it’s way out on its own especially past 200 hours and with it showing an historic solution on its own. Could this be a little like the old DGEX weenie model that was almost never right with its crazy solutions?