raindancewx

The support for a warm up late month is this - implies a big storm in the Southwest gets stuck around Dec 21-25 in a Rex Block and floods the East with warmer air in that period. Probably doesn't last long. Then you revert back to canonical -WPO for a while. But, later on, six 6-10 days out, the same maps over NE Asia imply storms get cut off over the NM/AX/MX/TX borderlands either via weak subtropical impulses or lost waves from the Northern jet. If some of those eject east when it is cold, that's a better signal for the East for storms and cold, but that's very late in December, probably Dec 30 into week one of January. The deep blues over southern Kamchatka were last there late Oct to week one of Nov, when we had the three week stormier period in the Southwest from Nov 15-Dec 5 or so as the timing pretty much always works at a 17-21 day lead. Your call or not whether you believe it.

The blend of the cold week this past week and the severe heat in November is pretty close to where the full winter ends up - maybe the green area finishes a touch west. But decent microcosm of what I expect - in theory cold enough for a ton of snow in the NE US, but probably too dry or poorly timed for actual heavy snow.

Another nice little snow event out here. Ski Taos has a two foot base, with Ski Santa Fe at 18". Albuquerque had a dusting to four inches generally. Nice to see after the record warmth in November.

The snow pattern, the 'smiley face', ID/MT to NM/CO to Ozarks to interior New England I mentioned in October is showing up. It's a good pattern, most of the US will get a lot of snow this year, but probably not where 95% of you live. You'll see everything shift south 200-300 miles during the peak cold waves, but it won't stay that far south for periods long enough for major snows to the south of the main smiley face.

Subsurface heat at 100-180W 0-300m down was pretty much unchanged from Oct-Nov. -0.47 in Nov, -0.41 Oct. Vastly smaller reservoir of cold water. We're on our third or fourth advisory level snow event for the high terrain locally. November was actually around 2x normal precipitation for the Northern half of the state, so the +6-8F temps didn't really matter at elevation. Still frigid above 8,000 ft on storm days. 14 inches of snow fell at Taos Powderhorn, 11,000 feet up, since Nov 17. They'll get 6-10 of dry power in all likelihood by Thursday morning. The resorts that get 200+ inches a year look like they're doing OK so far. For those who saw me include 2022-23 in the analog group at low weight - I do think there are some periods through April with extreme precipitation events in the SW, and that wasn't really present in 2024-25 or 2013-14. But they'll be much rarer than in that winter. But the one system in late November was pretty impressive for the moisture content.

Canadian update continues to insist on El Nino conditions developing in February at the surface. Likely by January below the surface. Fairly cold winter nationally. Has the cold look for the North-Central US I've been getting from analogs since Aug/Sept. My blend from Oct - (2013 x4, 2024 x4, 2018, 2022). Hasn't broken yet. I am expecting a pretty widespread warm up after a cold first 10 days or so - we'll see if that pans out.

I was in Japan for two weeks ending yesterday - no rain or storms at all for the entire two week period. Was interesting to see as Tokyo gets 3-4 inches of rain in an average November. Temps in the mid-50s to 70 each day. Even Mt. Fuji (12,000+ peak) didn't have any snow on the peak visually by the time I was going back to Tokyo on the Shinkansen from Hirishoma. December should have some cold but I've never expected a particularly brutal month overall. Part of it should be pretty cold and part of it pretty warm that is why I never emphasized it a month or so ago. Longer term, you see predominantly high pressure showing south of Kamchatka right now. So the storms that were flagged by that late Oct-Nov for the time frame now (lot of lows there, back then) will stop and reverse in about two weeks and the pattern should see a whole sale change for a bit. The CPC 6-10 and 8-14 outlooks show the pattern I expect in the "good parts" of the winter - pretty wet. Widespread cold. But it won't do that each week. I always assumed one part of Nov would be pretty cold in the East and another part much colder in the West, as that's what the blend of 2013 and 2024 implied - you can see that's played out a bit to some extent with a much colder pattern in the SW recently then at the start of the month. But the month will finish pretty warm nationally.

The group of years you picked is pretty terrible for the last full three months. Its completely wrong for the jet stream pattern over Asia for three months, and that determines what will happen for the build up of cold air in the Fall for us in the USA from both Russian and Canadian sources. You can already see the issues with it - because Asia is opposite the correspondence of the 'sin wave' so to speak puts the wrong signature over Greenland. My simple blend had it warm in October, yours is cold. The warmth I had over Northern Canada/Alaska is what will matter for the winter, and I showed it very warm for the period shown. You don't, you have the half degree warm / cold muddled crap that prevents any chance of your outlook getting US temps right later on when cold air is sourced from the North.

The cold wave in the West we've seen this week did show up at this time in 2013 for what its worth. I blend 2013 & 2024 for a reason - its not as cold/widespread as 2013 but definitely not as warm as 2024. The cold has displaced the warmth further east than last year.

From what I can see, no relevance for Dec, Feb, Mar for East Coast temps where it snows / where nor'easters are important. For the alarmists out there you can make the case whatever importance that was there in January is also rapidly diminishing - almost all of the East Coast in the 10+ inch avg snowfall climo zone is now in the borderline irrelevant correlation zone. The deeper blue zone is way south of where it is on the longer term map...

I've never understood the fixation with the PNA for you guys - its completely irrelevant for temps for the parts of the East where snow is heavily dependent on exact temps in big events. Storms and precip and patterns - sure. But who cares if you get storms if you can't determine the temp pattern from it? Its a pattern that matters for the NW and SE US, for temps in winter not the NE and SW US. These maps by the way show r, not r-squared. So anything below the 0.3-0.5 even for a long period of time is inherently unreliable. So I agree on the ENSO --> PNA relationship, but the point still stands - its not a big deal for the East where you guys live for temps in winter. Using Enso to predict PNA state is fine I guess but it just doesn't tell you much in the East in winter and hasn't ever really.

I've been telling you for literally a decade that ENSO has no direct correlation now, nor in the past to what happens in the East Coast for winter. So El Ninos are cold. Some aren't. Same for La Nina. Same for snowy/unsnowy. What is the point of these posts?

This is what Claude told me when I gave it this prompt - the newer versions of Claude are a lot better on pattern recognition than the older versions. What kind of winter do you expect in the USA following a September that looks like 2025? Looking at this 500mb geopotential height anomaly map for September 2025, I can identify several key features that would influence the upcoming winter: Key Pattern Features: Strong negative anomaly over Alaska/North Pacific (deep purple/blue) - indicating troughing Positive anomaly over western North America (yellow/green) - ridging pattern Negative anomaly over the North Atlantic - suggestive of trough there as well Strong positive anomalies in the high latitudes (around 60-90N over northern Canada/Arctic) Expected Winter Implications for the USA: General Pattern: This setup suggests a ridge-dominated western US and trough-favored eastern US pattern could persist into winter The strong Alaskan trough with western CONUS ridge is consistent with a negative Pacific-North American (PNA) transitioning toward positive or a split flow pattern Regional Expectations: Western US: Likely warmer and drier than average, especially in the Southwest and Great Basin Reduced storm activity in California Possible drought concerns Central/Eastern US: Greater likelihood of colder outbreaks reaching the Plains and East Increased storminess along the East Coast More variable temperatures with periodic Arctic intrusions Pattern Analogs: This resembles aspects of weak La Niña or neutral ENSO winters with a tendency toward cold East/warm West splits. The strong high-latitude blocking hints at potential for polar vortex disruptions, which could mean occasional severe cold snaps in the eastern 2/3 of the country.

I've been quite happy seeing the extra moisture this October. A lot of big systems (Lows) are forecast by NE Asia for a while, that's typically consistent with big systems moving through the SW at a 17-21 lead time this time of year. So I do see some support already for an active November. That's implied to some extent with the ACE to ABQ cold day correlation as well. I could easily be completely wrong about the winter, but its hard to see a warm winter nationally - I could see it regionally (SE/SW, or both). Serious question - I haven't looked - if you did a difference in proportions test for seasons without a US hurricane hit v. with a US hurricane hit, aren't the seasons without a hurricane hit far colder, or more frequently colder at least? I can't think of many winters following no US hurricane landfall in the US that are very warm, and consistently so.

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.