raindancewx

PDO is still extremely negative. https://oceanview.pfeg.noaa.gov/erddap/tabledap/cciea_OC_PDO.htmlTable?time,PDO 2023-08-01T00:00:00Z -1.68 El Nino, with -PDO values in August on this scale. 1951, 1953, 1963, 1969, 1991, 1994, 2006 I've been seeing people say this September is like 2004 because of the hurricane activity in the Atlantic / weak El Nino sense. In a sensible weather look though those Septembers have been nothing alike so far. We're actually at like B- similarity to early September 2015, which also had a big hurricane Bastardi and some of the other famous dudes thought would hit the East Coast. I think it was Isaias? (Edit: It was Joaquin). We certainly are not similar to 2009 at the moment. The cold in the West is wrong by placement in 2015 v. 2023 but you at least have a warm streak in the Plains and Northeast like this year.

This Summer in some ways reminds me of 2016. That was a winter that had Nino 1.2 warm relatively, with the western areas somewhat cool. So you had a strong subtropical jet / western storminess in winter, following a very hot Summer. The global upper level pattern was different in the Summer, especially on the Atlantic side, but you could do a lot worse for a 500 mb match than combing something like 1982, 2016, 2019 for a match to 2023. I'm not a fan of the QBO as a relevant metric, but the -QBO years do seem to be better matches right now. 1951, 1972, 2009, 2019, and a few others. The bigger El Ninos have tended to be near average QBO readings - 1997, 1982. The 2015-16 El Nino got blamed for breaking the QBO from what I remember, in terms of the regularly scheduled timing. The joke is the stuff that is determined by actual SSTs, like precipitation - looks very similar to the major El Ninos. It's just that the temp patterns are not great matches. The temps are more correlated to the PDO though in terms of spatial layout in the US. You can bitch and moan about the influence not behaving like you want - but this is pretty close. The upper high over TX was stronger than in the matching years, and CA had remnants from a hurricane...but its not like it's completely opposite the major El Ninos or something.

-PDO doesn't favor snow in the Mid Atlantic in El Nino. I said no correlation, not positive. They get so little snow that their good years are more fluky, even in El Ninos or favorable periods. But it is a negative feature for areas in the Northeast with more snow. In non-El Nino years, -PDO is bad for all of you, since it usually comes with La Ninas. Typically it is bad for the Southwest as well. The -PDO years favor warmth in the East and dryness in the Southwest deserts.

I looked at all the "counter" cyclical winters for PDO v. ENSO today, using Nov-Apr for the PDO. I'm using the old PDO index, not the stupid normalized index that replaced it. So 2009-10 as an example comes in slightly positive for Nov-Apr. Anyway, these are the El Ninos with a -PDO or a La Nina with a +PDO. Just about all of them have a major "snow hole" in the Northeast, which I'm defining as Virginia and north. When I say snowless/low snow, I don't mean no snow. Just that the entire region is below average in a notable way, despite surrounding areas or neighboring areas of the US/Canada being quite snowy. I'm basing these on snow maps for July-June from the MRCC site. The counter cyclical ENSO/PDO years seem to have more consistent storm tracks. So the Northern stream stuff whacks the same areas over and over and the southern stream stuff whacks areas over and over, and those tracks don't really vary much. A lot of other years have much less consistent tracks, and so you get less spread in the anomalies whether high or low for a given spot. https://mrcc.purdue.edu/CLIMATE/welcome.jsp 1933-34 - interior NE snowless 1938-39 - interior Virgina snowless 1942-43 - New England snowless 1983-84 - NJ / CT / E. PA snowless 1984-85 - Snowless outside W. NY 1985-86 - snowless outside W. NY 1995-96 - very snowy 2000-01 - snowless PA/VA 2005-06 - snowless NE US 2017-18 - snowles central VA/DC 1951-52 - low snow NJ, e. PA, W. NY 1953-54 - snowless 1958-59 - low snow NJ, E. PA, CT 1963-64 - low snow Maine, W. NY 1965-66 - low snow NY/CY/N PA 1968-69 - low snow PA, NJ, VA, W. NY 1972-73 - low snow PA/NJ/Southern NY & New England 1994-95 - snowless 2006-07 - low snow outside W. NY/PA 2019-20 - low snow outside Maine

For Boston, if you graph all El Ninos out by the PDO value for Nov-Apr, there is a pretty clear signal for the -PDO El Ninos to see less snow. That signal vanishes completely by the time you get to Philadelphia, and we also have no PDO snow signal in El Nino locally. Every blend I've been able to come up with has near normal snow for most of the Northeast US, outside of Southern New England, which is generally consistent with the image below.

Apparently, it was in December though? It's not like the warm pool wasn't there in December. You can predict whatever you want. But I'll take my chances on the PDO given that the western warm pool will continue to weaken relative to norms while the ENSO will be most pronounced relative to norms in that time frame.

There's never really been any correlation between the PNA and Nino 3.4 in December. It's best to treat ENSO as something that can, but doesn't always influence the various indices. The PDO on the other hand, is very strongly correlated to the PNA, much more so than ENSO in Dec-Jan. For Feb/Mar the PDO/ENSO essentially tie. I'm very much more on board with riding the PDO early for temps, and then dulling canonical El Nino effects later if you still have -PDO / +ENSO in Feb-Mar. https://psl.noaa.gov/data/correlation/table/corr.table_dec.txt

Locally, I can't find any 12-month periods with meaningfully less than ~4 inches of rain back to 1892. Our local "wet" season of July-Sept may finish under 1-2 inches at this point (v. 4" as average). El Nino precipitation long-term is about 10-30% above average by season. But even average precipitation on an annual basis would require a massive shift, since we only average 0.5"/month from Oct-May. My point with this is that US precip patterns in Jun-Aug look similar to a lot of the bigger El Ninos. So the subtropical jet / Pacific farting up moisture aspect of the El Nino looks correct, even if it is just from enhanced ocean heat rather than the canonical air pressure patterns. For June-Aug, you have pretty diametrically opposite correlations to the -PDO and +ENSO. So I don't find it surprising that some areas are responding to the -PDO and others to the +ENSO pattern. The -PDO is actually more correlated to the response by Indonesia than ENSO is in Summer.

This is my original map of the idea with site specific snow totals. So less snow as the yellow zone moves north.

I think the 60F annual temperature threshold is probably somewhere near Richmond in real time tbh. Just to be clear - the map I made is 7.25C to 18.25C in increments of 2.75C. So it's not exactly 5F, but very close. Part of the issue you guys have is that it's rarely cold enough for good snow outside of core winter, like 12/15-3/15 roughly. Here in the desert, it's certainly warming at night. But it still gets really fucking cold sometimes in Oct-Nov, and Apr-May. So we get fairly regular fluky snow in those months. You guys don't really have that to fall back on once the core season starts to warm/shrink. In the past five years alone I've had lows in the 30s every month from September-May. My point is the increase in moisture is more meaningful when its spread out over a longer zone of opportunity for snow. But you guys have a tight window for snow. Not like here when we've had snow over a foot of snow in Oct-Nov, Mar-Apr just in the past five years.

From about 20-50N, this is what I've found in terms of snow, when mapping out several hundred locations by their annual temperature v snow. In colder areas in the tropics (high mountains) it still doesn't snow as there is too little variation from Summer to Winter temps. <45F: Heavy snow is possible most of the year. Sites average 40"-750" (Bismarck, Caribou) 45-50F Heavy snow is is common in Fall-Spring. Sites average 30"-175" (Denver, Flagstaff, Buffalo) 50-55F: Snow is common, and frequently heavy in winter. Sites average 10"-60" (Boston, Santa Fe) 55-60F: Snow is common in winter. Sites average 3"-30" (Albuquerque, Philadelphia, Parral) 60-65F: Snow is uncommon, but not unheard of. Sites average 1-10" (Atlanta, Birmingham, Chihuahua city, Durango city) >65F: Snow is rare, sites average 0-3" (Houston, Miami) I've not really found exceptions at 60-year time scales for annual temps v. the snow ranges I'm listing above. Generally, the more arid spots are on the lower end of the scale, while sites adjacent to large bodies of water or on mountain tops are at the high end. Parts of the Northeast / Mid Atlantic (NJ / PA / MD / DE / VA) should be moving into the 60-65F zone pretty soon, if they aren't there already. It's still pretty common to get snow 3-7 winters a decade in those zones. Even down to old MX, Chihuahua (mean temps are typically w/in 2F of 65F) still gets ~3" on average with snow in ~half of winters. Albuquerque has had snow every cold season on record, at an average temperature of about 59F annually, but some of those years are under 1.0" and sites just 20 miles to the south or 300-600 feet lower in elevation go 1-3 years with no snow. The white xs in Mexico are examples of cooler towns that still semi-regularly see snow. The point is to show how it's tied to temps and not latitude. The green zone sees snow in ~nearly all or all winters. The yellow zone is where you can go years without meaningful snow. You guys are on the border of the yellow / green zone now, with the yellow advancing north. What I've found near the transition from the 55-60F zone to the 60-65F zone is that big March storms tend to start happening more frequently in mid-late February, with March starting to behave more like a full-on Spring month.

CPC updated Nino 3.4. August came in at 28.16C, which they call +1.30C. In older periods, when the 30-year average is lower, it's more like +1.50C. You can see the SSTs are for August in Nino 3.4 are colder than 1987, 1997, 2015. Actual SSTs are pretty close to a blend of 1997 / 1972 in August outside Nino 4. Year: 1.2 / 3.0 / 3.4 / 4.0 1972: 23.38 / 26.74 / 27.94 / 28.75 1997: 24.96 / 27.71 / 28.74 / 29.29 Blend: 24.17 / 27.22 / 28.34 / 29.02 2023: 24.33 / 27.09 / 28.16 / 29.69 Not really sure why everyone is obsessed with the Indian Ocean / Nino 4 being warmer than the Eastern zones - you can clearly see that was the case in years like 1997 too.

It's actually pretty amazing how similar US temps for Jun-Aug overall are to Jun-Aug 1982, if you add 1F to 1982. That's despite all the bitching about not locking in / getting the forcing we're supposed to get. I mean...1982 had the forcing right? I posted some maps in the winter 2023-24 thread for anyone curious.

Here is 1982 warmed up 1F v. 2023 for Summer - The pattern I've noticed in looking at three month periods is we follow 1982 pretty well for the placement of subtropical highs and heat to the south, but not so much the placement of the cold air. I'm building my analogs around the idea that the stronger El Ninos are probably a better match for TX/MX and the SW US, an OK match for areas just north/east of that zone, and not a good match for most of the Northern US. Actually think Northern Mexico may have a really cold winter, while no one in the US is materially below average. -PDO is a pretty strong late winter warm signal for the East, but a cold signal for the MX/ US West. El Nino is a strong cold signal SW US / MX in December, and January would be a blend. Last year I liked 2012/1984 as the primary temperature blend idea for winter, with the other years mostly in there for precipitation and timing fixes. This year I like 1951/1982 as a blend, with 1972/2009 likely to show up as the El Nino weakens in late Winter or Spring, and 1997/1991 in there for early winter. I do think 1972, 1982, 1997, 2009 are the better analogs for precipitation. See for yourself - Feb - Apr March-May

I don't think it's physically impossible for Nino 3.4 to gain something like 4C year over year. But it's never come close to doing it. In close to 100 years of data even a 2C gain is very rare. Last winter was 25.95C in winter. Nino 3.4 averages ~26.5C in winter. No reason to believe this will go much above 28.0C for winter. Even those 2.0C gains are like once a decade. May is also a good indicator - you don't really warm up much in DJF from May even in super strong events.

Locally, we've never had a July-June with under 4 inches of rain back to 1892. But July-September is our wet season (~4")...and it looks very dry (0.7" now). So either we're going to snap to at least normal precipitation over the next 8 months (since September looks dry), or we're going break our record for dryness in a year. My guess is we snap back hard to wetness. To get to actual normal totals for a year - 8.67" for the past 100 years - we'd need basically 2x normal rain/snow for Oct-May when we average ~0.5" liquid equivalent per month. The mechanics of that snap back are interesting to think about, especially since this El Nino looks like it will be ~ongoing decline until it collapses as early as late Oct-late Dec. Outside of the SW, I would say the NE US tends to snap back to dryness after very wet Summers. Look at the wettest Summers in Boston - the El Nino blend is 1976, 1982, 1986, 2006, 2009, 2019. 1 1955 24.89 0 2 2023 20.33 0 3 1959 19.68 0 4 2021 19.64 0 - 1982 19.64 0 6 1938 19.07 0 7 1998 17.42 0 8 2006 16.87 0 9 1931 16.03 0 10 2013 15.95 0 11 1986 15.02 0 12 1946 14.90 0 13 2011 14.54 0 14 2019 14.44 0 15 1985 14.12 0 16 2000 14.03 0 17 2008 13.93 0 18 1989 13.85 0 19 2009 13.36 0 20 1976 12.87 0

Among the years I posted as hottest Chicago Septembers, the 1963-64 cold season is crazy for how the temperature profile played out in winter. For records back to 1892, February 1964 is the "least average" month on record in Albuquerque. The high is legitimately 13 degrees below average. I don't think any other month since 1892 is even more than 10/11 above/below average. The Oct-May highs locally on a monthly basis are pretty cleanly +/-3F for standard deviations. So that year is a really interesting exception, likely in part due to the volcanic influence and/or AMO shift that was ongoing.

September looks fairly close to my tentative analogs on the Canadian. I have no faith in the winter outcomes on the models yet especially at the surface. The heat core is stronger and displaced somewhat Southeast, but it's close. Here are the warmest Septembers in Chicago btw, El Nino only - since you have a +8 to +9 forecast on the Canadian. Some pretty severe winters for me in there, along with a few duds. 1939, 1941, 1963, 2015, 2018, 2019

I mean...why would it behave like a Super Nino? Whatever index you use, traditional, MEI, SOI, SSTs, etc, it's not reached anywhere near super strength. I've been expecting a low 28C peak sometime around 10/1-11/30 for a while. We don't really seem like we're going to spend much time, if any, above 28.5C, if you're talking about months from Oct-Feb. The Super Ninos were near 29.0C in recent cases by ~9/1. The 60-year (1951-2010) older/colder August average in Nino 3.4 is 26.65C - so we're at most +1.5C. The more recent 30 year period averaged 0.2C warmer. It's not really a "strong" event yet. 02AUG2023 24.7 3.4 27.1 1.8 28.1 1.1 29.5 0.8 09AUG2023 24.4 3.3 27.0 1.8 28.1 1.2 29.6 0.9 16AUG2023 24.3 3.3 27.1 2.0 28.1 1.3 29.6 0.9 23AUG2023 23.9 3.1 27.2 2.2 28.3 1.5 29.8 1.1 This event is in the low 28s right now, likely 28.25C or so for August. I've bolded August / September. For the moment, we're actually more like 1987 than the super events. 1982-83 took off much later than 1997-98 and 2015-16. This event may be more like 1982. 2023 25.83 26.29 27.18 27.96 28.40 28.57 28.30 -99.99 -99.99 -99.99 -99.99 -99.99 2015 27.05 27.17 27.75 28.52 28.85 28.90 28.75 28.79 28.93 29.08 29.42 29.26 1997 26.01 26.38 27.04 27.98 28.58 28.82 28.86 28.75 28.85 29.08 29.12 28.89 1982 26.67 26.59 27.41 28.03 28.39 28.26 27.66 27.58 28.21 28.71 28.62 28.80 1972 25.62 26.30 27.09 27.89 28.32 28.18 28.14 27.95 27.95 28.26 28.61 28.69 1965 25.66 26.19 26.94 27.38 27.99 28.09 27.90 27.97 28.01 28.17 28.12 27.96 1987 27.68 27.88 28.27 28.39 28.56 28.65 28.59 28.42 28.36 27.96 27.77 27.54

By the way, since we're in high solar conditions now, it's worth noting that there is some evidence in the research of the sun modifying the severity of MJO pulses via...something. Solar wind? UV radiation? A guy on here in the SE forums used to talk about coronal mass ejections as the likely mechanism. This is from an interesting paper I read awhile ago - https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JD028939 One stupid sanity check I like to do is just look at past years in multiples in 11. You almost always find one near perfect match when ENSO aligns. Same thing tends to happen at intervals of 30, on the closest timed ENSO match. 2023, 2012, 2001, 1990, 1979, 1968, 1957, 1946, 1935. Just from that list, 2012 is still one of the top SST matches globally (many severe heat waves, derechos, Gulf hurricanes, etc and the oceans were warm in Summer, Nino zones included). 1979 had notorious, record heat in the SW following a severely cold winter for most of the US, so fairly similar. 1968 has the El Nino hurricane hitting FL running SW to NE. A lot of you guys like 1957 too. On the 30-year scale, you have 1993, 1963, 1933. Just from those, 1963 is a decent match. That's a very severe winter in a lot of ways though. Several of those periods at the 11-year intervals followed recent winters of notorious cold waves in Texas BTW (Feb 2011, Dec 1989, and so on).

Michael (2018) & Gladys (1968) in developing El Nino both hit the NW coast of Florida running SW->NE in October. It's interesting seeing the hurricane now. Suspect we'll see another burst of Gulf activity in mid-October before the season dies off. Several of the older El Ninos, like 1951 and 1972 did see Nino 4 get to 29.0C+ readings for a few months mid-year. CPC generally has the Nino zones warming about 0.1F per decade. That's part of why I've been looking at those years. If you remove 0.5C everywhere in the tropics in 2023 those years are similar to now spatially. Both -PDO setups too. By the way - all the years with developing Ninos that had -PDO readings through Summer? Those that flipped positive for the upcoming Oct-May, flipped by the end of August.

Now that the August heat wave centered on Texas is baked in, we've settled back into a very similar national temperature profile as in June. Heat is most severe in the middle of the US, and cool pockets exist by the coasts. This is one of my theories for the Fall-Spring, when the subsurface warms. Unfortunately, I don't think it is going to be the dominant pattern for the cold season. It's been a while, but I can remember patterns where the jet stream does this in the winter for long stretches. I don't think its crazy to expect the entrenched Midwest/Plains dry spot to persist via a high over the Midwest. Eventually we'll get a May 2015 / 1957 and that'll destroy it, but may be late Spring before it comes. At some point I need to go back and see if I can find that dry spot in a developing El Nino.

This is the real regression I use for anyone who cares - rather than the dumbed down version. B4 is ONI in DJF, B5 is annualized sunspots in July-June, and B6 is ONI in DJF in the prior year. For the past 29 El Ninos, that formula is accurate +/-1.7F in 26 of 29 El Ninos. ABQ El Nino DJF High = (2.899*B4^2)-(0.0161*B4*B5)+(1.566*B4*B6)+(0.0001046175*B5^2)-(0.017933*B5*B6)-(0.30338*B6^2)-(8.5467*B4)+(0.006026*B5)+(0.9541*B6)+(54.495) El Nino ONI DJF Sun Jul-J ONIp DJF Tmax Obs Tmax Proj Error Error 48.9 1939 1.0 125.9 -1.0 49.8 48.7 1.10 0.90 1940 1.9 94.4 1.0 49.8 49.3 0.50 0.90 1941 1.1 76.5 1.9 48.9 49.7 0.83 0.03 1945 0.8 95.8 -0.5 47.8 49.5 1.67 1.07 1951 0.5 62.8 -0.8 50.0 50.6 0.58 1.07 1953 0.8 9.5 0.4 50.7 50.2 0.53 1.83 1957 1.8 281.6 -0.2 50.5 50.6 0.13 1.57 1958 0.6 255.4 1.8 50.4 50.5 0.10 1.50 1963 1.1 29.1 -0.4 43.6 47.4 3.83 5.33 1965 1.4 37.1 -0.6 44.4 46.1 1.70 4.50 1968 1.1 155.7 -0.6 48.4 49.3 0.87 0.47 1969 0.5 148.6 1.1 52.0 51.6 0.43 3.13 1972 1.8 75.4 -0.7 45.2 45.5 0.27 3.67 1976 0.7 23.2 -1.6 48.1 46.5 1.60 0.80 1977 0.7 84.1 0.7 50.5 50.5 0.00 1.60 1982 2.2 129.2 -0.1 47.9 47.5 0.43 0.97 1986 1.2 19.1 -0.5 46.7 46.9 0.15 2.20 1987 0.8 65.3 1.2 50.0 50.3 0.33 1.07 1991 1.7 177.8 0.4 48.0 48.0 0.02 0.90 1994 1.0 36.9 0.1 54.4 48.8 5.57 5.47 1997 2.2 54.9 -0.5 47.1 46.6 0.50 1.80 2002 0.9 131.0 -0.1 50.7 49.8 0.90 1.80 2004 0.6 55.3 0.4 50.2 50.8 0.63 1.27 2006 0.7 20.1 -0.8 46.6 48.3 1.67 2.27 2009 1.5 13.2 -0.8 46.6 45.3 1.27 2.33 2014 0.6 90.7 -0.4 51.4 50.8 0.63 2.53 2015 2.5 55.8 0.6 51.4 51.9 0.50 2.50 2018 0.8 5.5 -0.9 48.2 47.3 0.90 0.70 2019 0.5 2.1 0.8 49.8 52.1 2.30 0.90

El Nino winters locally are pretty predictable for highs using a regression incorporating: - Nino 3.4 for winter - Nino 3.4 for prior winter - Solar conditions The ideal case is a strong El Nino following a strong La Nina with low solar. Generally speaking the scale is this: Weak El Nino ------------> Super Warm El Nino (current winter) Super Warm El Nino ------------> Super Cold La Nina (prior winter) Solar Maximum -------------> Solar Minimum (July-June annualized) The top scale I think of as 26.5C to 28.5C, where 28.5C = 10, and 26.5C = 0. (1 point = 0.2C) Middle scale is 24.5C - 28.5C where 24.5C = 10, and 28.5C = 0 (1 point = 0.4C) Solar is essentially 0-300 sunspots, where 0 = 10, and 300 = 0 (1 point = 30 sunspots) A year like 2018-19 was strongly supported to be somewhat cold: Nino 3.4 (4), Nino 3.4 prior (7), Solar (10) - a 7/10. This year, I get something like this: Nino 3.4 (~7.5), Nino 4 prior (6.5), Solar (4) - a 6/10, maybe 7 if Nino 3.4 goes up. A particularly severe winter would be 2009-10 locally: Nino 3.4 (8), Nino 3.4 prior (7), Solar (10) - 8/10 Very roughly, each average score above/below 5 corresponds to -1 / +1 against long-term averages. So I expect a -1F type winter here, while 2018-19 was more of a -2F winter against 1991-2020, while 2009-10 was a -3F winter.

You have to be careful with the solar stuff. The cycles are not always 11 years. Historical range from min to min or max to max is 9-13 years. So a year that looks like it is still climbing or falling can be the top/bottom of the cycle. The prior min was centered on February 2019, so we may already be at the peak (Feb 2024 would be +5 years from the min). We've been seeing the tendency reversal in temperatures I speculated on earlier. The SW US heat wave in July coincided with a record drop in subsurface heat for a warm ENSO event. Now the subsurface is warming, and it is cooling off quickly locally. We've had several cool days this month after none at all for six weeks.