raindancewx

Just for reference - NAO was different. But globally its pretty similar. Blocking should show up at times, its just when? I'm assuming the super persistent warmth/high pressure by Japan means on balance the NAO is not predominantly favorable for Nor'easters in the dead of winter int he Northeast. But during the transitional periods (Nov/late Feb-late Mar) I am more optimistic for big systems by the NE than in recent years.

Forgot this. I have the counts for cold waves in the 80-120 ACE La Ninas locally. For whatever reason, the tendency shows the low-solar, low ACE La Ninas seeing severe cold locally late (February) while the higher solar, low ACE, La Nina years see it early (Nov-Dec). So low solar Feb 1955/1985 have the most days 5F or more below average locally. But Dec 1971, Dec 1988, Nov 2000, Nov 2022 have far more solar activity. The years that go to El Ninos, 1971 and 2022, also see higher numbers of cold days in Nov-Dec locally in these La Ninas. My best guest is one big cold outbreak mid Nov-mid Dec for cold, and then smaller outbreaks later. La Nina, 80-120 ACE # Of Days by Month, AVG Temp 5F or colder than daily mean in ABQ Year Nov Dec Jan Feb Nov-Feb 1954 1 9 10 15 35 1971 6 15 8 5 34 1984 6 7 8 11 32 1988 9 11 9 5 34 2000 17 4 12 6 39 2022 14 5 5 7 31 Blend 9 9 8 8 34 # Of Days by Month, AVG Temp 10F or colder than daily mean in ABQ Year Nov Dec Jan Feb Nov-Feb 1954 0 3 3 12 18 1971 0 7 3 3 13 1984 2 3 4 7 16 1988 2 5 5 4 16 2000 10 0 3 0 13 2022 5 0 0 2 7 Blend 3 3 3 5 14 For July-June - 1954-55 is around 19 sunspots, 1984-85 is around 26. 1971-72 is about 101. 1988-89 is around 188. 2000-01 is around 163. 2022-23 is around 110. 2025-26 is probably lower than 2024-2025 (149) but still in the 1971, 2022, 2000, 1988 range.

I don't necessarily expect the cold to show up as severely as it does on those maps. It probably will come in warmer by 1-3F in two of the three months in Jan-Mar, and then as severe as depicted in the other(s). Taken verbatim the weighting would make Jan-Feb as cold almost as both 2014 and 2025 nationally, which is pretty unlikely. I also don't expect the WPO to flood Canada/Alaska with warm air all winter. If models are right the PDO/ENSO should move toward their warmer cycles and you should see a corresponding change in the Northern Hemisphere patterns. The 100-180W heat content at the equator down to 300m got to -1.33 last in Jan 2025 but is trending warmer/weaker this year, so you should see an easier breakdown of whatever the dominant pattern is late winter when the ocean heat content warms rapidly. It went all the way to -0.06 by March 2025. If we top out at -0.8 to -1.0 this year, the flip to 'warmth' that coincides with the surface pattern ENSO flips should happen a lot faster. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt

By the way, I settled on this for analogs for temperatures for the cold season: Oct, Nov, Dec, Jan, Feb: 2013-14 (x4), 2024-25 (x4), 2018-19, 2022-23 Mar, Apr: 2019 (x4), 2023 (x4), 2014, 2025 Couple pretty cold months in there, but its not really long-lasting or consistent where it shows. Snow anomaly looks like a smiley face, going from Montana-Idaho border to NM-CO border in the West, Ozarks shooting NE to interior New England/Maine for heavy snow. In between (OK/NE New Mexico, North TX, etc) will have some nasty ice storms. I went below average for snow northern plains. I expect very little snow here for most of the actual winter, but there are windows in November, late Feb-late Apr that should be productive. For winter precipitation I used the Mar/Apr weighting for wetness/dryness. Jan-Mar has retrograding cold shots as the La Nina rapidly collapses while cold air is still around. So by March its Plains/West, but for January Plains/East. Edit: Conceptually, I settled on these blends for a couple reasons - the upper air pattern in July-Sept does look like a simple blend of 2013, 2018, 2022, 2024 globally. SSTs are close too. That's not a bad match for the US in Sept or Oct either. But the straight 2013/2024 dominated blend is much closer for US temps than the equal weight blend. In 2024-25, the cold was highly concentrated in January nationally and then to the east in February. My La Nina Atlantic ACE to Albuquerque Nov-Feb cold day count index implied 23 days would be at least 5F below the daily average. We had 24. This year with ACE still only 96, the implication is 31 days at least 5F below the daily average. I still expect the La Nina warm signal to show strongly, but the cold wave signal is pretty strong. I'm expecting either one-two major cold waves or several smaller cold snaps. The lower ACE also implies locally "severely cold days" - 10F or more below daily average - should be around 12, instead of the projected 7 last year (we actually had 8 or 9 I believe). The precipitation blend is still predominantly dry in the southern US, but much wetter than 2024-25. Additionally, a lot of the hurricane seasons with near no to no activity in the Gulf end up pretty cold late - 2013-14, 2010-11, 1981-82, 1962-63, 2014-15, 2022-23 - if going into an El Nino or trending warmer in Nino 3.4 y/y.

Relatively canonical +WPO look for temps in Oct so far - if displaced slightly. November is very different though if it holds.

Cold patch this month in the West should expand. Not really that similar to last October when the West was blazing. The cold season still looks much better than last year to me too. You could already see what we were heading into by the end of October last year - Lot of drought nuking rain coming the next five days. That near record setting storm in the North Pacific is a feature of the winter by the way, not a bug. You will have very powerful storms in the winter.

Still looks fairly close. Both the blend with and without 2007 are decent US temp profile matches for Sept 2025.

This article is pretty consistent with my thinking on how to model winter precipitation patterns in the US. It's strongly supportive of a wetter winter nationally than last year, despite what the models show. https://opensnow.com/news/post/how-atlantic-ocean-temps-could-impact-la-nina-2024-2025-winter-forecast Recent seasons on the Canadian have been depicted in an MJO pattern of 4-5 for winter. The models are showing 6-7 for this winter. That's very different from recent winters, look at the depicted east African precip pattern at the equator. Look at Brazil shown wet v dry in phase five. It's not 5 like in recent years. It looks like 6-7 to me, not perfect but better than the others. We had 4-5-6 for precip nationally last winter, but made drier by the Atlantic features. Again - this match holds up for a lot of my methods, although it isn't quite what I expect. But it did have 106 ACE as an example which still feels about right.

I'm expecting another fairly shitty season for eastern snowfall overall. Recent culprits are not applicable this season though. More generally, for those of you who swear by ONI, the Indian Ocean and Atlantic Ocean are relatively cold at the tropical latitudes, so subtracting out their heat as part of global warming doesn't 'enhance' the R portion of the RONI for La Nina strength as in prior recent years. The cold current by Japan looks it has woken up a bit, and the Atlantic and Indian Ocean are both colder relative to last year than the tropical Pacific. The North/South Pacific are moving toward a +PDO slowly as well with the warm C by the eastern side of the basin showing and the cold tongues showing to the west. Colder tropics overall should mean less MJO relevance in the warm and cold phases, less convection for thunderstorms. High solar is typically a modifier on MJO progression east to west/intensity if you look at it. We also had pretty favorable patterns for sea ice this year, so there should be pretty substantial cold build early on. Last September was pretty cold in Northeast Russia and that cold kept sloshing around until it was forced out of the Arctic in January in a pretty severely cold national pattern for a few weeks. That part of Russia looks pretty cold again this September. I don't consider the AMO/PDO to have flipped this year. But even 'moving' toward opposite phases should reduce the drought tendencies we've seen in the US over the blue areas. You can see last year was close to the exact opposite of figure A (+PDO/-AMO). We should see a much better/wetter winter nationally with the Atlantic much colder and the NE Pacific so much warmer, especially as the cold tongue begins to assert itself by Japan. In the months/seasons with most direct influence from AMO/PDO on precipitation you should see completely different rain/snow patterns to last year. Colder AMO should alter Southeast ridge positioning, independent of the type of La Nina that shows. A lot of the storms that went to bring big rains/snows to KY/TN last year should be east/west of their positions last year, with the PDO hurting KY/TN moisture. My main issue for NE snow is that precip patterns nationally usually have specific signatures nationally in the Summer that have not really shown up for 2025. I think the subtropical jet will not cooperate for eastern storms, even though at times the Northern stream of the jet will go pretty far south this winter.

Here is how the global blend I mentioned a while ago looks for September - 2013, 2018, 2022, 2024 minus 2007. Not half bad. Given that ACE is heavily favored to finish under 100 now, I'd go colder than the blend with -2007, especially Plains/Southwest.

If you use the seasons above that finish at 0-40 ACE for Sept (I doubt it will be that high or that low but 20 seems about right with some activity likely by month end), you end up with this much smaller group of La Nina seasons. 1942 (9.9 Sept) 1956 (9.4 Sept) 2007 (29.0 Sept) 2016 (27.3 Sept) Those are your 30-50 ACE June-Aug, with 0-40 ACE Sept La Nina years. Can narrow down more as September finishes. Very cold in the North & West in January of those years, fairly cold in December & March too. Feb very warm. As a reminder, 20 ACE would be a 100 kt sustained wind hurricane observation recorded at each of the six hour official advisory times...for five days in a row. Since 100 kts x 100 / 10,000 = 1 ace point (1 pt x 5 days x (24 hrs/6 hr space per observation) = 20). We may have the next Atlantic tropical storm in a day or two, but its already pretty far west to have a super long period as a major hurricane starting from nothing, if it develops. In a La Nina context, the 2017 September is useful anti-log - very low solar (we're very high now), very high activity September (175 ACE). You also had more of a classic hot West/cold East Summer (Jun-Aug) in 2017 which we didn't see this year. High solar is probably weakly correlated to inactive hurricane seasons long-term. But its a little hard to tell as we haven't had a whole lot of super high solar years (July-June) in recent times with the Atlantic warmer. July 2024-June 2025 finished at 149 sunspots/month, but prior ~peaks/near peaks have been well over 200-250.

The actual global pattern for June-August 2025 looks a lot like a blend of 2013, 2018, 2022, 2024 to me, with -2007 in as a confirming anti log (it had low heights south of Alaska as an example). The blend with -2007 also has a similar look to Sept 2025 so far in the US. The temp blend with 2007 supports the West getting pretty cold in Fall, then it spreads East, peaks in December, and retreats until February when it returns for the Plains. Pretty boiler plate. I don't fully buy it. But it does support some pretty cold periods in the Southwest, which is increasingly likely the longer the hurricane season stays dead (now looks likely until Sept 16). The four main years average out to a slightly inactive hurricane season, with cold showing locally in mid-Nov to mid-Jan (2013), mid Dec-mid Jan (2018-19), early and late in 2022-23 (Nov, Feb-Apr 7), and January 2025.

Some context on La Nina ACE through August. We finished at 39 in the Atlantic. 30-50 La Nina ACE, through Aug 31 since 1930 () and then final ACE after the slash. 1942 (36.1) / 62.5 1956 (32.5) / 56.7 1964 (39.7) / 153 1998 (44.7) / 181.8 2000 (43.7) / 119.1 2007 (38.0) / 73.9 2010 (45.1) / 165.5 2011 (36.7) / 126.3 2016 (31.5) / 141.3 excluding the Jan 2016 system 2017 (30.4) / 224.9 2020 (43.0) / 179.8 2021 (44.4) / 145.7 Blended final total - 135.9. Ten most recent La Ninas average 146 ACE (2007-2024). October is almost always below 70 ACE even in hyper-active seasons, and Nov is almost always under 35 ACE even in hyper-active seasons. So the quiet September days start to add up pretty quick if you're behind with nothing active. If you throw out 2017 (since we're very unlikely to be anywhere near 175 ACE in Sept), you end up with a map consistent with my research showing the low ACE La Nina hurricane seasons have more frequent cold snaps in the Southwest. 2020 had the mid Sept/late Oct/Feb severe cold, Feb-Apr 2022 (and 2023) was very cold locally. Feb 2011 very cold. Jan 2008 is very cold. Nov-Jan 2000-01 is very cold. Dec 2011 very cold locally. September should be quite clarifying for which years in the group are the good matches. The Summer temperature pattern was fairly close to some kind of blend of 2007, 2020, 2021

The Canadian update shows a cool Fall for the East (Sept-Nov) with La Nina dead by February, likely dying mid-January. May not last long enough to be official, but will be La Nina in practice. Cold winter for the Northern US. I suspect the cool Fall idea is right but overdone. Canadian had the right idea for August but it was a bit too cold. Wet Junes locally often precede a fluke/heavy out of winter snow events. So cold availability in the transitions to/from Winter, but not Winter itself is consistent with my expectations for seasonal behavior locally. I'm expecting a small number of very powerful lows with a lot of cold and moisture in the Fall here (likely mid-Oct to mid-Nov if I had to guess) and then again in Spring (mid-Feb to early Apr). Actual winter should be warm, although I do think the models are overdoing the dryness nationally for winter right now. If the hurricane season remains inactive, I'd also expect a pretty major cold wave again when or just after the La Nina collapses, likely focused on the Northern and Western US. ACE is about to dip below average again and low La Nina ACE is correlated with more frequent cold days in the Southwest in Nov-Feb.

One thing I look at entering the Fall is the overall level of heat south of the United States. When you get warm ups ahead of storms in the Fall/Winter from much deeper heat sources it can really kill the cold shots in terms of the averaging out of the monthly/seasonal temps. From 1961-2024, the tendency for the top Atlantic hurricane seasons is for the West Coast to be pretty warm Jun-Aug. We haven't had that this year. There have been pretty cold periods on the West Coast this summer. We don't appear to be heading to a top ten type season based on the composite. 2005 has a passing similarity but had different placements for the subtropical features. But really 1995/1999 are the only two of the ten super seasons that have any kind of cold Summer pattern at all for the West Coast. The precipitation pattern is fairly similar but much wetter in the Plains and a bit drier in the East. But a lot of these active hurricane seasons have storms hitting the east/gulf to drive up their totals in Jun-Aug, which we haven't had this year. The precip pattern difference looks like 2025 is the active hurricane seasons, but on a spoke centered on FL, with the core of the moisture rotated counterclockwise toward the Plans. To me that implies completely different positioning of the Bermuda High from the hyper active seasons. But we'll see.