GaWx

The SE may need a major SSW to help turn things around during the last few days of Feb. But in meantime, today’s Euro Weeklies are even warmer for Feb as a whole with some areas a whopping 7 AN, near the normal for Mar!

The last 3 0Z GFS runs have consistently progged a 60N zonal wind min of +13 on Feb 13th, which would be ~one week after the progged S-G Dipole max. We’ll see whether or not these progs actually progress to a major SSW on/near Feb 12th-13th. Regarding the progged 60-90N 10 mb temperature rise, today’s 0Z is the most impressive yet with a whopping 31K rise to +238K on Feb 14-5! Yesterday’s rose only to +231K and Jan 28-29 runs rose only to +227-228K:

Regarding the bolded: the current +QBO is, indeed, the exact opposite of 2/12/2018’s -QBO. However, it is the same as 2/16/2023’s +QBO. Also, Joe D’Aleo found (and I confirmed) a strong correlation between high Solar/+QBO and major SSWs. So, it now being +QBO shouldn’t on its own reduce the SSW chance but if anything should raise the chance. Furthermore, 2/12/2018 was during very low solar. We now have the opposite, which per Joe enhances the chance a whole lot. 2/16/2023 was during pretty active solar as I assume you know. In the meantime let’s first see if there’s even going to be one. It’s fun to see how these evolve!

The SE’s best bet to get the pattern to change back to cold by the last few days of Feb and through at least much of March is to have a mid Feb major SSW. As of yesterday, the EPS and GEFS means were still showing no indication of that being much of a possibility with instead showing strong SPV related mean 60N zonal winds at midmonth. However, I was alerted earlier tonight by Dr. Simon Lee tweets that a strong Scandinavian (high)-Greenland (low) SLP Dipole was on the models Feb 6-7. The reason that’s important is that he’s done studies showing that this Dipole is often a precursor to a major SSW by ~~1 week. The last few GFS runs have been hinting at a much weaker SPV in mid Feb. We should know much more by the Sunday runs. In addition, Joe D’Aleo did a study that concluded a high chance for a major SSW during high solar/+QBO winters like 2024-5. Dr. Simon Lee’s study of S-G Dipole: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JD030940 0Z 1/31/24 GFS 168: strong S-G Dipole:

Further to the above fwiw, the 0Z 1/29 GFS (latest available) brought the mean wind down to 19 m/s on Feb 13th and 13 m/s on Feb 14th: In comparison, the prior run (0Z 1/28) had it bottoming out way up at 28 m/s on Feb 13th: So, the GFS had a significant drop on 1/29. I’ll be watching the GFS closely because it was ahead of the ensembles in advance of 2 major SSWs since 2023.

You may be onto something that I wasn’t paying attention to til just now when I saw this on the 0Z GFS 168 for Feb 7: check out the strength of this Scandinavian-Greenland Dipole! Is this what you were looking at yesterday? This paper was written by Dr. Simon Lee and others about the 2/12/2018 major SSW that was not forecasted beyond 12 days: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JD030940 He talks about a S-G Dipole pattern (strong high over Scand/low over Greenland) often being predictive of major SSWs before models actually do so (they’re still not). This dipole peaked ~2/6/2018, or only one day prior to the forecasted peak of ~2/7/25! Aside: the major SSW of 2/16/23 was also preceded by a similar early Feb S-G Dipole! Dr. Lee’s latest tweets: Despite the models still not showing even a hint of a major SSW, I’ve been wary about it based on Joe D’Aleo’s study showing a heightened chance during high solar/+QBO. I took his idea and looked at the actual #s. I considered high solar for DJF to be 135+. DJ will be ~145. If Feb ends up 115+, it would qualify. Check this out: 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, a whopping 7 of these 8 winters had at least one major SSW! Just food for thought. The progged strong Feb 7th S-G Dipole is consistent with a potential major SSW on or near Feb 13th if it were to actually occur with similar timing to 2018. If so, look for hints on the EPS/GEFS starting this weekend. IF there were to be one ~Feb 13th, look out for the potential of a colder E US pattern starting ~Feb 27th and lasting through at least ~Mar 15th and quite possibly the entire month or further. Anything to keep the bugs quiet would be a winning pattern for me!

We’ll see whether or not they go back to the slightly AN to NN mid to late Feb maps of yesterday. But today was painful to see. Unlike you I like cold regardless of snow, which is very rare here. There’s way too much humid heat May-Sept. I’d much rather the Weeklies show it cold. When they’ve been cold this winter (late Nov/early Dec, much of Jan), they’ve been accurate. They’ve also done well with warmups. That’s why I hate seeing them this warm. Regardless, the 2-3 day cold snap within week 2 of Feb remains on the model consensus.

I never noticed there was a different Euro Weeklies chart for surface! I always look at 2m. For determining frost on ground, I’d think surface would be more important than 2m. On good radiational cooling nights, you may already realize that surface is sometimes couple of degrees colder than 2m due to colder air being heavier. But 2m is official. And thus I’ll continue to use those. On nights after a cold front has just come through and the cold winds are advecting colder air, I’d think sfc would tend to be slightly warmer. When sun is out, the ground should be warmer than 2m, especially in summer.

-I thought 2m and surface were the same. -Please show me where they’re different. -Shades of red: anomalies in degrees C 1st: 0 to +1 2nd: +1 to +3 3rd: +3 to +6 4th: +6 to +10 5th: +10+

Unfortunately for cold lovers like myself, today’s Euro Weeklies for 2/17-23 & 2/24-3/2 totally reversed yesterday’s much colder runs for those two weeks and are back to a solid mild signal: 2/17-23: The other 5 weeks of the run through 3/16 are about as warm or warmer. The implied prog for Feb as a whole is for ~6F AN in much of the SE. The good news is that there’s still plenty of time for especially late Feb to reverse. But the overall signal for a mild SE in Feb has been persistent with a dominant SE ridge and +AO/+NAO (canonical La Niña Feb). And for those worried about cold rains in early Mar, this run says “no worries” like it did yesterday.

Unfortunately for cold lovers like myself, today’s Euro Weeklies for 2/17-23 & 2/24-3/2 totally reversed yesterday’s much colder runs for those two weeks and are back to a solid mild signal: 2/17-23: All 6 weeks of today’s run are this warm or warmer in the E US. The implied Feb avg is ~4F AN NYC and ~5-6F DC south. Would be very close to March normals in SE. Many places in the area DC south would have a Feb ~13-15 warmer than Jan. Be that as it may, there still appears to be a good shot at a 2-3 day long cold period starting Feb 8-9.

I don’t disagree for the most part. But I was responding to CWG’s tweet saying this: “MJO approach to phase 7 could flip pattern back to cold side for U.S. by 2nd week of February, similar to super-warm late December to cold early January flip from this winter.” So, the tweet was referring explicitly to temperatures and said nothing about snow. Thus, my response was referring to just temperatures based on what 0Z/6Z model consensus was showing. I wasn’t at all addressing snow, which is much more unpredictable, especially 11+ days out, since it is so dependent on precise storm track and actually having a storm at the right time. Also, some do care about temps on their own.

Even in a mild (cold) month, a short period or two of cold (mild) isn’t uncommon. 0Z/6Z ens means are suggesting a 2-3 day long cold period is quite possible in the E US starting ~Feb 9th-10th but otherwise they’re mainly on the mild side NYC south and restrengthen the SE ridge immediately afterward. So, the means for the first half of Feb would still easily be AN NYC south. Will keep watching ens mean trends for Feb 9th+ to see how they trend going forward. Phases 6-7, especially 6, lean toward the AN temp side in Feb fwiw. Phases that are BN on avg in Feb are 8, 1, 2, and 3, especially if amplitude isn’t strong.

Even in a mild (cold) month, a short period or two of cold (mild) isn’t uncommon. 0Z/6Z ens means are suggesting a 2-3 day long cold period is quite possible in the E US starting ~Feb 9th-10th but otherwise they’re mainly on the mild side NYC south and restrengthen the SE ridge immediately afterward. So, the means for the first half of Feb would still easily be AN NYC south. Will keep watching ens mean trends for Feb 9th+ to see how they trend going forward. Phases 6-7, especially 6, lean toward the AN temp side in Feb fwiw. Phases that are BN in Feb on avg are 8, 1, 2, and 3, especially if amplitude isn’t strong.

Yeah, I fully realize that it takes on average a couple of weeks to translate vertically. But about all of Jan has been much stronger than average with high 50s to 60 also 1/7-14 (see image below) and it was pretty high before that. Yes, I realize you didn’t say significantly colder.

Even a weak SPV isn’t anywhere close to being a reliable indicator for a cold E US. Consider that the SPV mean wind was actually peaking near a record high upper 50s on the days that the Deep South had an historic snow/sleetstorm (1/21-2)!

However, the latest Euro Weeklies and extended GEFS still show no strong signal for a major SSW in Feb like they did for the several that occurred in 2023 and 2024. But Joe D’Aleo did find a connection with high solar and +QBO that says to be on guard for that possibility: EPS (1/29): shows 60N 10 mb zonal winds dropping 2/6-15, but mean drops only to a little above climo with most members at 15-40: GEFS (1/28): mean drops to 40 on Feb 11th, but that’s still well above 20 climo (**edited for correction): *Edited for correction

Good news for you as of now. There’s no indication for a cold first 1/3 of March on today’s Euro Weeklies. Though it could of course change drastically since it is over a month away, this map shows the opposite of cold in the E US: This is for Mar 3-9:

Both the CFS and the Euro Weeklies this winter have had the E (including the SE) with far BN temps several weeks in advance (and the coldest anomalies on the globe) and they remained consistent with the cold thereafter. These are just 3 examples of the many times they did with strong signals for cold in the E US: Issued 12/28/24 for 1/13-19: CFS 48 forecast mean (4 members, 12 runs 12/25-28) for 1/11-17: CFS 48 forecast mean (4 members, 12 runs 12/29-1/1) for 1/15-22): In contrast, today’s significantly colder Euro map vs yesterday for 2/17-23 is at least as of yet nowhere near as cold: Latest CFS 48 forecast mean for 2/20-7: still mild in E US

Well Mr. Moles, I wouldn’t say in bank but 3”+ storms in Feb in GA have tended to occur mid to late Feb to Mar 2nd as well as in late Jan. For an unknown reason early Feb has been quiet. Could be merely randomness.

Though still not showing anywhere near BN cold and still mild through 2/16 in the SE, the new Euro Weeklies have cooled off from AN to only slightly above to NN in N portions 2/17-3/2 in the SE US. We’ll see whether or not that is a one run aberration. 2/17-23: (2/24-3/2 looks similar in SE)

There’s been no measurable snow/sleet in ATL during Feb since 2014. In the late 1800s, Feb was the snowiest month.

The Euro Weeklies have been amazingly accurate this winter several weeks out! This 500 mb map below was released on Dec 15th for Jan 6-12, which was at the release time 22-28 days in the future. One can see that the coldest anomalies on the entire globe were targeting the E US even 3-4 weeks out, which verified well. The cold on these and the 2m maps intensified as the period got closer. The Euro did similarly well for the subsequent two weeks (Jan 13-19 and Jan 20-26) well in advance concentrating the coldest on the planet in the E US. For Feb they’ve been harping on a much milder pattern in the E US especially south of New England (canonical La Niña Feb pattern) thanks to a -PNA/+AO/+NAO (near opposite of Jan). Based on the Euro’s impressive accuracy weeks in advance and La Niña climo, I see no reason to bet against a much warmer pattern, especially MidAtlantic/Ohio Valley south. This Euro 2m temp map is for Feb 3-9: much warmer than Jan especially most of E US and much colder SW Canada and NE Canada/Greenland: This one is for Feb 10-16: similar

850 mb temperatures for the airmass a week ago were as cold as -37C in the upper Midwest! That’s not seen too often.

Today’s Euro Weeklies for Feb are ~5F AN vs yesterday’s ~+4F. More like a normal March than Feb. But cheer up as that would still be 2-3F cooler than Febs 2023, 2018, and 2017. So, it could always be worse.