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GaWx

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  • Four Letter Airport Code For Weather Obs (Such as KDCA)
    KSAV
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    SAV, GA
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    weather stats, sports, walking/hiking

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  1. GaWx
    More from Webb about the SSW: The wave pattern that forces stratospheric warming events varies from case to case. Displacement events (wave 1) require an Aleutian low and a Scandinavian-Kara Sea block, but splits of the polar vortex (wave 2) do not necessarily. This particular stratospheric warming event actually starts out as a split type (wave 2), and then morphs into a wave 1/displacement type event as the Aleutian low becomes established later. The tropospheric trigger for this event is clearly traceable to the Eastern Pacific w/ divergent wind anomalies from active convection propagating poleward into N America and then eastward into the North Atlantic jet stream, eventually forcing the Kara Sea/Scandinavian block that sets this entire stratospheric warming event into motion. Also, note that early in the model forecasts, wave 2 amplitude dominates the -NAM/AO changes, wave 1 comes later and is largely confined to the mid-upper stratosphere initially at least.
  2. GaWx
    -1952-3 only barely missed a 2nd one in Jan with it getting down to +1 fwiw. -I had thought a +QBO reduced the chance for a mid to late winter major SSW during +1.3+ El Niño. However, upon further review, that may not be true: Here are the +1.3+ peaking El Niño events with a +QBO and whether or not they had a Jan 15th+ major SSW: 1957-8: yes 1982-3: no 1987-8: yes 1994-5: yes 2015-6: yes So, that’s 4 of 5 (80%) +QBO +1.3+ Nino with a Jan 15th+ SSW ———————— What about -QBO Nino winters? 1965-6: yes 1986-7: yes 1991-2: no 2009-10: yes 2023-4: yes So, that’s 4 of 5 (80%) -QBO +1.3+ Nino with a Jan 15th+ SSW. So, it’s a statistical tie for Jan 15th+ SSWs chances during +1.3+ El Niño.
  3. GaWx
    Webb is right. All but 3 of the 12 +1.3+ peaking Ninos had at least one major SSW Jan 15th+: 57-8: Jan 30th 65-6: Feb 24th 72-3: Feb 2nd 82-3: none 86-7: Jan 23rd 87-8: Mar 14th 91-2: none 94-5: Feb 4th 97-8: none 02-3: Jan 17th 09-10: two in Feb 15-16: Mar 5th categorized as an SSW but also by others as a near earliest FSW on record 23-4: mid Jan and early Mar
  4. GaWx
    Mitch, The modeled 10 mb/60N wind rise after the historic dip is by no means faster than what commonly happens with SSWs, especially early season SSWs. Looking at the image below, one can that the plunges downward from SSWs are often followed by pretty sharp rises soon afterward. By that time, the SSW has already done its “damage” so to speak. Look at the SSWs in here (circled). I count 8 SSWs prior to Jan 1st: 1952, 1958, 1965, 1968, 1981, 1984, 1987, and 1998 Most of these other than 1984 rose fairly steeply within a few weeks, which is what the models are showing for 2026 (assuming they will even be right obviously). Even some of those after Jan 1st rose steeply. @snowman19@Winter Wizard
  5. GaWx
    John, I’m being extra wary of the GEFS AO progs because they’ve been verifying significantly too -AO, especially in week 2: July 1st-Oct 28th verification: AO +0.6559 per image below vs mean GEFS progs of (all from image below): day 7: +0.287 (too -AO most days since Sep 1st) day 10: +0.0533 (too -AO since Sep 1st by larger amount) day 14: -0.086 (too -AO since Aug 25th by even larger amount)
  6. GaWx
    Thanks. I don’t doubt the bad actors! For me this is introducing more variability for Dec than I had assumed previously. Based on @snowman19posts on +QBO/ENSO analogs as well as my own research to confirm Adam’s mild E US forecast, I had been thinking mild Dec except possibly NN SE, especially deep SE. But with this historically very early SSW coming, I feel that there’s increased uncertainty for Dec. Per @Stormchaserchuck1the avg lag from an SSW to first getting well down into the troposphere early in the season is 35-40 days if I recall correctly. This would mean ~Dec 9-14 for it to first reach well down. And then it would last for a period of time (most likely 2-3 weeks minimum per history). Thus, this increases the possibility of a cold overall E US Dec, especially mid to late month and especially SE US, vs my prior thinking from very low to a nontrivial chance.
  7. GaWx
    Nino Nov 1-15 avg 10 mb/60N mean zonal wind (m/s) 26: projected +2 09: +15 04: +16 58: +17 06: +18 68: +18 77: +19 79: +20 76: +20 14: +21 72: +23 51: +23 87: +24 Avg: +25 94: +26 57: +26 65: +27 63: +27 18: +28 91: +28 69: +29 15: +30 02: +30 86: +30 82: +30 23: +32 53: +32 97: +34
  8. GaWx
    Per Eric Webb: interesting I have a sneaking suspicion that the extreme eastward shift (& intensity) of this year's El Niño potentially has something to do w/ the unusually early stratospheric warming event that's being forecast. I also wonder if there's a theoretical point where we shift the Indo-Pacific Warm Pool so far east that we actually don't end up getting a massive torch in December in the SE US & we just haven't observed an El Niño event strong/eastward shifted enough to challenge this idea. Perhaps, the trough that's normally buried in the Desert SW in December of a "normal" strong-super Nino bleeds eastward into the SE US instead, mirroring the eastward shift in convection/stronger subtropical jet stream forced by the extreme eastward shift in the mean warm pool. There are certainly some significant unknowns/wild cards on the table w/ this winter despite the normally high predictive power that comes with strong El Niños.
  9. GaWx
    Yes, they are by a good margin and that’s important. I’m not disagreeing at all and don’t think anyone is. I’ve pointed out a number of times about 26-7 being the most E based on record. But at the same time, we’re right to also point out that 3.4 is coming in weaker than progged, which is interesting and a fact and makes it even more E based but also means it’s coming in weaker officially. So, in future references to the official strength of the 2026-7 Nino, it appears it will not be as strong in the official table as what the Euro and BoM were predicting.
  10. GaWx
    Yes and no because the official ENSO strength is determined by Nino 3.4, which is what we’re referring to, rather than other regions. So, in terms of official strength, it technically is coming in weaker than these overshooting models. At the same time, it has become more E based than the models had due to the E regions coming in stronger.
  11. GaWx
    The BoM has been overshooting every near month forecast by a significant margin (0.4+) since April with it averaging 0.5 too high! Oct is joining the club: Here was the forecast for Oct as of just 2 weeks ago, which had Oct way up at +3.5: Look how far down the Oct 24th MTD is: only +2.8! So, full Oct is likely going to end up at no warmer than +3.0, which would make its Oct forecast verify 0.5+ too warm and thus continue the trend that started with April: This tells me that Nov will have a good chance to end up verifying ~0.5 too warm or at ~+3.2 vs its forecast of +3.7. Either Nov or Dec will very likely end up as the peak. So, if BoM monthlies were to peak at, say, +3.3, then the NOAA monthlies would likely come in cooler and peak at ~+3.0 and the trimonthlies would likely peak at ~+2.8, which is where I am currently (not much change from before).
  12. GaWx
    Mitch, I just realized I had a typo as I called the winds on those charts “anomalies”. I realize they’re not anomalies and are instead absolutes but for some reason I typed anomalies. Thus, I just corrected the original post. My original thoughts are unchanged. I think my erroneously originally referring to them as anomalies threw you off. So, the +5 and +4 are actual winds rather than being 5 and 4 above normal. Is that what threw you off? —————— Aside: Ignore the trolls. Apparently moderation is nonexistent here.
  13. GaWx
    Mitch, Danny Devito says no and I agree with him. 1976 and 2009 had very weak winds but they didn’t go <0. I was looking at El Niño Novs that dipped to +5 or lower. 1968, 1976, and 2009 were the only three to do so per ERA data. A +5 dip is very weak.
  14. GaWx
    The chart below has 10 mb/60N winds back to 1949. According to it, Nov 2026 is going to per ERA obliterate the old record (all of the way back to at least 1949) earliest SSWe whether it gets down to 0 (major SSW) or stays just above. The earliest SSW on record is 1952’s ~Nov 15th SSW. So, 2026 is headed to possibly beat 1952 by ~11 days! ———————— Looking at the above chart for only El Niño Novs, the only three that got to +5 or lower per ERA5 in Nov were 1968 (-5 on Nov 27th), 1976 (+4 on ~Nov 15th), and 2009 (+5 on ~Nov 15th). These three had the lowest DJF AO of any winters since at least 1949-50. Thus, these very strong winter -AOs were quite possibly connected to a large extent to the very weak Nov SPV period. Thus, a case could be made for a better than average chance for a strong -AO averaged out in 2026-7 despite the lack of seasonal model support: 1968-9: AO -2.3 1976-7: AO -2.6 2009-10: AO -3.4 @Typhoon Tip *Edited for typo
  15. GaWx
    The official NOAA Nino weekly (based on OISSTv2.1) was at +2.5 for the avg of last week and is likely ~+2.6 now. Based on this as well as forecasts, I’m currently thinking their weeklies will likely peak no higher than low +3’s, which means monthlies will likely peak no higher than ~+3.0. That would mean a trimonthly RONI peak probably in the upper +2.0s.
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