GaWx

Of course, the sweet spot will vary depending on the region. I already analyzed the MEI for the SE US including TN: the 10 coldest El Niño winters back to 1951-2 were 1957-8, 1963-4, 1965-6, 1968-9, 1969-70, 1976-7, 1977-8, 2002-3, 2009-10, and 2014-5. Per Webb’s table these were the rounded DJ MEIs: +1.5, +0.9, +1.3, +1.2, +0.8, +0.8, +0.7, +1.0, +1.1, and +0.5. So, range of +0.5 to +1.5 for the DJ MEI with a mean of +0.95 and a median of +0.95. So, DJ MEI sweet spot near +1.0 for the 10 coldest in the SE. The 6 coldest were 1957-8, 1963-4, 1969-70, 1976-7, 1977-8, and 2009-10. DJ MEIs for these 6: +1.5, +0.9, +0.8, +0.8, +0.7, and +1.1. So, range of +0.7 to +1.5 with mean of +1.0 and median of +0.85. So, I’ll be rooting for a significant rise in the next three bimonths from SO’s 0.26. I’d like to see a rise of +0.2+ back to +0.5+ in ON. Was 2023’s drop of 0.33 from AS to SO the largest back to 1948 for El Nino? Actually, no as 1986 dropped slightly more (0.40) before it rebounded 0.50 from SO to ND, which I’d love to see. Webb’s 1948-2019 MEI: https://www.webberweather.com/multivariate-enso-index.html

No, dropped a little from +1.98 to +1.97.

WCS updates: -Nino 3.4 dropped very slightly to +1.97 from +1.98 -PDO dropped from -0.84 to -0.93.

OHC has again been readjusted warmer but also was just extended out 5 more days: the result is by far the warmest this Nino with ~+1.6 as of Nov 22 and is still suggesting more sharp rises! Those very warm TAO maps are finally being reflected here. It looks like Nov will easily end up the new warmest month for this event so far barring something unforeseen:

In addition to what the EPS has been showing, possibilities are there for SSW late Dec-early Jan per 11/27 extended GEFS, too:

I like the every six hours frequency. However, that’s CDAS based, which is quite cold biased.

This is easily the strongest cold signal for the first week of January in the E US of any Euro Weekly run that I’ve seen and as strong a cold signal as for any land area on the globe for then. Keep in mind this is way out in week 6, when it is hard to have a strong signal away from normal in an ensemble mean. This timeframe is consistent with an MJO prog favoring cold in the E US. Per @griteaterposted MJO chart the prog is for a slow moving fairly weak (just outside the COD) phase one then, which tends to favor cold in the E US, especially during El Niños: Looking further out on griteater’s MJO prog, the week after this is progged to continue to move slowly in weak phase 1 and then entering weak phase 2, which would favor another cold week Jan 8-15. The last time the first half of Jan was cold dominated in the E US was in 2018. Though not El Niño, it was mainly in a moderate MJO phase 2:

Even with it that large, it is imo likely mainly due to day to day flux. Even the drop of 0.17 in 5 days isn’t too far out of line from a correction considering it had risen ~0.5 in just 10 days. So, it has given 1/3 of that back. Now, if it were to drop too much more from here, I might have second thoughts.

The cyclonicwx Nino 3.4 dropped by a similar amount, from +2.15 to +2.03, the biggest daily drop in a very long time:

Meanwhile, WCS just reported the largest daily drop in Nino 3.4 in two months with a drop from +2.10 to +1.98! That’s the coolest on WCS since Nov 16th and certainly unexpected by me: The daily WCS PDO dropped to -0.84 from -0.77.

Yeah, I was using unrounded. For rounded, what @griteater said makes perfect sense.

I agree with your general ideas. Per ERSST, Oct was +1.66 and Nov is likely going to be in the general vicinity of +2.0. So, for OND to come in +2.0+, Dec would probably need to come in near +2.35, likely a tough task. The better chance may be with NDJ (I’m guessing you agree) with its first month near +2.0. For that, Dec could come in, say, ~+2.1 and Jan, say, ~+1.9 or, say, Dec ~+2.2 and Jan ~+1.8 and a +2.0 ONI is reached either way.

As expected, today’s weekly OISST based NOAA update (for last calendar week) for Nino 3.4 came in at +2.1, an increase from the prior week’s +1.9. Also, for the first time since way back in early Feb, the weekly Nino 3.4 anomaly came in warmer than that for Nino 1+2, which remained at +2.0. Today’s weekly NOAA update: Nino 1+2: +2.0 (steady) Nino 3: +2.3 (up from +2.1) Nino 3.4: +2.1 (up from +1.9) Nino 4: +1.5 (steady) https://www.cpc.ncep.noaa.gov/data/indices/wksst9120.for

No worries, Mitch. If you decide to delete your two recent posts, I’ll also delete my replies to clear the thread.

I know. I already posted the 11/26 update here as it updates by late afternoon (before night). So, the next update (11/27) will be by late afternoon today:

The OHC is still being adjusted upward for the same timeframe and is now showing a new high on this graph for this event of ~+1.40 with further ongoing sharp rises being suggested. Keeping in mind reporting lag as this particular graph is updated only through ~10 days ago (midmonth instead of late month), Nov has a good shot to exceed June as the warmest month of this Nino so far in the monthly table. This is for 5N to 5S down to 300m and uses a 1991-2020 base:

The 11/1-18 Euro Weeklies runs were making me think a weaker than normal Dec SPV model bias quite possibly was in play due to major can kicking. The date of the SPV going below climo slipped from ~12/1 to 12/25 and thus it stayed a month+ out/like a mirage. However, the last 8 runs have come all the way back along with extending into early Jan with the last 5 runs being very impressive with today’s having the most major SSW members (30%). Thus, I no longer think a model bias is in play. Furthermore, there’s modest support on the extended GEFS. And don’t forget that the CFS fwiw is supporting a weak SPV this winter. So, I now fully expect a weak SPV will at least dominate Dec (with or without a major SSW) and may very well go into Jan. Now if we actually get a major SSW late in Dec, it could rebound within a few weeks as they sometimes do.

It looks great once again on the EPS for those who want a weak SPV. Similar to yesterday, the EPS mean goes weaker than climo 12/3 and is well below climo 12/7-end of run (1/10). Not that it is necessary, but this run implies the highest % of members yet with a major SSW (between 12/24 and ~1/11), 30%, which beats the 25% on yesterday’s run. The climo % chance of a major SSW by Jan 11th is only ~20-25%. More specifically, this run has 12% of its members with quite a potent major SSW (dip to <-10), which is tied with the 11/25 run for the highest of any run yet!

It looks like the most recent OHC was readjusted up to ~+1.35, which is about as warm as at any point on this graph and this appears to suggest more warming ahead. On average, Nov is the warmest OHC month though Dec was 0.45-0.50 warmer than Nov in both 1986 and 1991:

It still looks great through early Jan with the EPS mean having the SPV become weaker than the climo avg starting Dec 2nd and it being well below climo Dec 5th through Jan 9th. Keep in mind that ~a week ago, the EPS mean wasn’t going below climo til Dec 25th! This run has a whopping 25% of its members with a major SSW between mid Dec and early Jan, which is the highest of any run yet and is well above the climo chance for that period:

WCS PDO resumes large daily rises with latest -0.72 vs -0.86 prior day vs ~-1.28 7 days ago (Edit for 11/25 WCS: PDO -0.77, Nino 3.4 +1.10)

CFS prog vs Normal 10 mb N Pole temp: (C)/anomaly Dec -58 vs -70/ +12 Jan -51 vs -60/+9 Feb -49 vs -55/+6 So, latest CFS has DJF N Pole 10 mb temp anomaly at +9 C implying a weak SPV for the winter.

Per the following 0Z 11/24 GEFS 10 mb map for 12/19, it implies a significantly weaker SPV vs what was implied on the 0Z 11/18 prog (similar to 11/24 vs 11/18 Euro): 11/24 run for 12/19: note how much warmer is W Siberia to NW Can, further N/stronger S AK high, and sig weaker SPV on this vs 11/18 run map below: these strong trends are hints of an increasing shot at a SSW ~12/20: 11/18 run for 12/19:

Still looks great!

Check out the image of precip anomalies for 1979-2012 for Nov-Mar below: note that the precip bulge center was at 170E on the JFM map whereas it is ~180 on the newer map. The 170E centered map is near phase 6, a typically warm phase. It moves E from there but that still would in theory mean a good bit of 6. On the newer map though it is centered at 180, which is between 6 and 7, and this in theory should mean less of the warm phase 6. I’d love to see the bulge move even further E and thus allow in theory a higher freq of phases 8 and 1: