raindancewx

Subsurface heat for 100-180W continues to rapidly thin. It often peaks in November. Some examples of big Nov-Dec drop offs. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt Year Oct Nov Dec 2023 1.13 1.45 1.11 2018 1.47 1.25 0.92 2015 1.91 1.78 1.20 2009 1.04 1.75 1.36 1997 2.56 2.30 1.02 1994 1.12 1.16 0.80 A decent blend to match Oct-Dec is: 1994 1.12 1.16 0.80 2009 1.04 1.75 1.36 Blend 1.08 1.46 1.08 2023 1.13 1.45 1.11 Here is how Dec 2023 finished btw. Generally above +3 above average north of I-40.

In El Nino / La Nina with opposite phase PDO I find it's more of indicator of EPO/WPO stuff than the PNA. I never really expected the PNA to be negative. Still an El Nino at the end of the day. PNA has always been kind of over rated to me as an indicator of anything anyway. Look at the last week with the most strongly +PNA values/setup of the month - that's the look I kept getting blending strong El Nino with -PDO. By the way, that Kamchatka low on 12/18 does look like it is going to come through the SW US on Jan 5 or so, which is in the 1/3-1/7 period I identified back then. We'll see how it goes, still a way out.

I actually think January should be a relaxed continuation of December. Still warm in the North, cooler South, but not 15F above average anywhere. There should be actual honest to goodness cold somewhere in the South in January. I think you'll see some northward expansion of the southern cold at times into both the East and West, with alternating troughs. What CPC has for early January is pretty close to my outlook for January from October. Didn't really have a warm month. The CFS frames for Dec 26-28 look too warm to me for January.

One of my pet theories from the volcano is that a lot of would be snow events became rain or mix events because the marginal boundary level stuff that would work in a lot of barely cold enough storms now has too much moisture/heat from the higher dew points globally. A lot of Nor'easters have some kind of warm nose, or warm mid-layer boundary that prevents an event from staying all snow or even all sleet/snow. I think that's part of what happened in 1994-95, which was after Pinatubo, but during a period when all the aerosol material had fallen out of the sky, while the heat enhancing crap remained. I'm sure there will be plenty of pretty good storm tracks later in the year, with setups that would have 32F ish temps at the surface, but I'm not sure they'll work this year.

I believe this will be the warmest December on record for the lower 48. Most of the northern lower 48 will finish +3 to +15. It's probably something like +8F for the northern states, and +3F for the southern US. Locally we've had some slightly cold days recently. We'll probably finish Dec between +2 and +3. I put the +/-0F line for seasonal anomalies in my winter outlook half way into the yellow areas of the SE and SW US, so that still looks on target. I thought the rest of the country would be quite warm. Warm El Nino months in the Southwest are largely a reflection of diminished diurnal ranges from higher dew points. We've not dropped below 20 yet - which is fairly unusual here. But every winter on record has fallen to at least 19. I'm sure we'll get there at least once. The highlands of Mexico have seen the traditional east based El Nino effects in some respects, despite also matching the -PDO look I showed before. The central highlands as far south as 20N have had highs in the mid-50s this month with rainy days, despite being at relatively low altitudes, like 6,000 feet. During the drier periods when the subtropical jet has shifted north, they have some lows in the 30s as well.

The tendency for the more recent Strat Warm events to not be cold in the East is why I've not been super into following it. We more or less "know" where it is going to dump cold right? I mean Minneapolis has never had a winter average above like 27F since like the 1930s. It's 35F there in December month to date, and they average about 20F for the winter. Seems like the obvious spot for SSW cold to dump is...the Plains. Again. Since any dump will come during a period when the El Nino is rapidly weakening, I'd expect some SE ridging in response like in prior years. This is all assuming of course that the cold even comes to the US. But I doubt Minneapolis will finish +15F if the record is +7F for their warmest winter in 90+ years.

Boston should literally be at a foot of snow or so through 1/5. Instead you have less than an inch, with none in the forecast. To get to average, you'd need a +30% period of above average snow, which is a huge reversal from a 90%+ deficit, and that +30% reversal would need to last for 3 months from several small storms in an extended cold period. Otherwise it needs to come from a couple big storms. The issue with the latter is that you can see from the NYC/Philly totals that the bigger storms tend to not come when those cities are heading into week two of January without any snow. I'm also not super sold on the strat warming thing. A lot of those years come when the entirety of the coldest Northern Hemisphere climates are super warm in early winter. You don't really have that - it's been very cold in Russia and China this month. The Arctic Oscillation is already negative, and the NAO will be too by the end of the year, and you guys still don't look particularly cold in the short term.

I think the main issue with this event is that the most typical El Nino conditions happen in rapid periods of subsurface warming. We had that...in March. Remember when California got nuked with snow and people died? Haven't had any rapid warming in the subsurface since. The warmth itself doesn't really do anything. We're the most sensitive part of the US to El Nino here, and we've always responded better to the "warming" of the ocean than the "warmth" of the ocean if that makes any sense. The subsurface hasn't really warmed much at all since Spring.

Here is a look at total snow for Boston, NYC, Philly in El Nino if we make it to Jan 5, 2024 without an inch. Once you get to January without an inch of snow in NYC/Philly, odds of a rebound start to deteriorate very quickly. Boston has a bit more time, but the general rule applies. Years with <=1" snow through Dec are essentially running 70%+ below average through a large portion of the cold season by time (Dec is a low snow month, but still 1/4 of the main Dec-Mar window in the NE coastal cities). It's not super common to rebound from a -70% pattern for snow to a long duration period of above average snow that can offset it. El Nino is a better snow signal further south, so there is more volatility in the rebound towards averages for DC/Philly than NYC/Boston in the rebounds. Anyway, still no snow on the models for the cities through Jan 5. I did have 1972, 1991, 1997 as analogs, so this all makes sense to me. Boston, <=1.0", El Nino, Oct-Jan 5 1957-58 - 44.7 2006-07 - 17.1 2015-16 - 32.6 2018-19 - 27.4 Blend: 30.5" NYC, <=1.0", El Nino, Oct-Jan 5 1965-66 - 21.4 1972-73 - 2.8 1991-92 - 12.6 1994-95 - 11.8 1997-98 - 5.5 2006-07 - 12.4 2015-16 - 32.8 Blend: 14.2" Philly, <=1.0", El Nino, Oct-Jan 5 1958-59 - 5.1 1965-66 - 27.4 1972-73 - 0.0 1991-92 - 4.7 1994-95 - 9.8 1997-98 - 0.8 2004-05 - 30.4 2006-07 - 13.4 2014-15 - 27.0 2015-16 - 27.5 2019-20 - 0.3 Blend: 13.3"

One of the more interesting things about this event has been the conflict between the -PDO and the El Nino. In Mexico, this month, we have a dead on match to -PDO conditions. In the US, the incredible warmth in the Dakotas and MN is very much a match to stronger El Nino years, and not at all a match to the -PDO years. I said in my outlook that -PDO is a cold December signal in old Mexico, while a warm Nino 3.4 is a cold Feb signal in old Mexico. I really think they may have a much colder winter than the US relative to their local averages.

Tropical Tidbits has waters by Peru running below average now. Some cooling building West. If you remember March 2023, you had a period of rapid subsurface warming. This December is largely opposite. March was severely cold in the West and very stormy. Been warm and fairly quiet this month. Early December, when the rising heat content was rising before reversing was certainly cooler for most than the more recent days. For what it's worth, the heat content should continue to rapidly thin...and sure enough the CFS has another +15 type month for areas in the Northern Plains in January at the moment.

You all are welcome to come visit our mountains - the skiing has been nice. The secret to the high elevations out here is that it's almost always 0-30F or so at the base level of the resorts, ~8,000 feet, from mid-Nov to mid-Mar.

First major window for a colder/stormier pattern to me is coming up in mid-January. Take the period below and add 45 days - that's my guess for timing. Roughly Jan 7-21. After that, add another 45 days, Feb 21-Mar 7. If you blow those two periods in the East, I think it's just another shitty winter. As the El Nino collapses in Feb-Apr, there should be some extraordinarily powerful storms moving through the US as the balance of power in the Pacific changes. The cold period shown followed multiple storm days here, which looks fairly likely again in the Jan 3-7 period I outlined a week ago using the Bering Sea Rule. We'll see soon enough.

57-58 had the QBO in the opposite phase of this year (+7 in Dec on the dataset), along with the PDO opposite. It's been fine as a match for December, but you can get lots of matches to this type of look in an El Nino December. The main issue with 1957-58 isn't even those indexes - it's the fact that it was followed by another El Nino. That implies completely different processes at play in late winter that we won't see this year. The Indian Ocean Dipole was flipping hard toward a look that leads El Nino last year, and now it is doing the opposite. More generally, the stratospheric event in 1958 was much later in January than what is expected to happen this year. The deeper you get into Jan-Feb, the more correlated the +PDO is to severe Eastern cold and hardly any years are above 1957-58 in that regard. I don't really think the SSW even added that much - it would have gotten severely cold regardless.

I'll just leave this here. Boston, <=1.0" Snow by Dec 31, El Nino ------------------- 1941-42 - 23.9 (Oct-May snow) 1953-54 - 23.6 1957-58 - 44.7 2006-07 - 17.1 2015-16 - 36.1 2018-19 - 27.4 -------------------- Mean: 28.8" (Oct-May Snow) NYC (Central Park), <=1.0" Snow by Dec 31, El Nino ------------------- 1941-42 - 11.3 (Oct-May snow) 1965-66 - 21.4 1972-73 - 2.8 1977-78 - 50.7 1986-87 - 23.1 1991-92 - 12.6 1994-95 - 11.8 1997-98 - 5.5 2006-07 - 12.4 2015-16 - 32.8 ------------------- Mean: 18.4" (Oct-May Snow) Philly, <=1.0" Snow by Dec 31, El Nino ------------------- 1941-42 - 5.1 (Oct-May snow) 1958-59 - 5.1 1965-66 - 27.4 1972-73 - 0.0 1977-78 - 54.9 1986-87 - 25.7 1991-92 - 4.7 1994-95 - 9.8 1997-98 - 0.8 2004-05 - 30.4 2006-07 - 13.4 2014-15 - 27.0 2015-16 - 27.5 2019-20 - 0.3 ------------------- Mean: 16.6" (Oct-May Snow) ABQ, 0.0-2.0" Snow by Dec 31, El Nino (1.0" so far) ------------------- 1939-40 - 4.0 (Oct-May snow) 1963-64 - 10.0 1969-70 - 7.1 1977-78 - 11.5 1994-95 - 9.4 2002-03 - 2.8 2009-10 - 4.2 2014-15 - 15.2 ------------------ Mean: 8.0" (Oct-May Snow) No snow on the GFS or Euro for the Northeast cities through 12/31.

This event really isn't in the same echelon as the top El Ninos by the traditional SST measures. -PDO really sticks out v. 2015-16 too. That will matter again in JanuaryFebtuary, after being irrelevant in December.

CFS basically has the same look for December carrying into January. I've been pleased with the pattern so far, it's nice and wet. The mountains here are getting a ton of snow. The resorts have 2-4 foot bases at the moment. We've had back-back wetter than average months for the first time since Jan-Apr 2019. The CFS basically has no skill until a day-two days before the new month starts. It's actually remarkable how little El Nino changes with time. Some of the El Ninos in the 1940s were absolutely brutally cold in Russia like this year, and very warm in the US like this year has been to date. Close to a literal recreation of the conditions that helped kill so many Nazis.

I agree that January will be warm. But I think it's best to focus on the years in your list that had a huge disparity in Dec temps for Russia v. Canada as the roll forward criteria.

I've been studying this purple Russia, v. red Canada thing. It's pretty interesting if you roll forward the results in an El Nino. A lot of El Ninos have either the red or the purple in the right place, but not both. 1965 and 2002 are not horrible matches, but 1997 is a lot closer. Jan-Mar 1998 looks pretty close to what I expected in my analogs for the winter. It's not a particularly cold period, but everyone would have their shots at major storms if you look at the months individually.

If this verifies, it's pretty hard for me to see any area of the northern US verifying cold, or even near average for Dec-Feb. Well...Alaska.

I'm seeing people get a bit excited about early January. The colder pattern for the East that we saw in parts of November should cycle through in January. But it's not going to be as early as week one. The simplest issue is this low south of Kamchatka yesterday. That should be between 32-37N, about 105-108W in the time frame of Jan 3-7 using the Bering Sea Rule. Lows that deep tend to force tremendous warmth out ahead of them to the East. It may only be for 1-3 days, but that's a large portion of a week. But these systems are often followed by pattern changes. More generally, the entire GFS run has the Low north of High low in East Asia look (+WPO). It's difficult to get the Eastern US real cold with that in place. The look below is essentially a giant high over Texas and a giant low over CO or NM pumping up massive heat from the South/MX/TX in between them, and then the whole thing translates East. I have composites of what East Asia looks like ahead of the greatest snow events in NM/CO for the past 50 years or so.

I'm pretty excited. Going to see back to back wetter than average months locally for the first time since Jan-Apr 2019. 4.5 years+ - what an abomination for consistent moisture. As far as wildcards for the rest of the winter: Anyone have a read on the volcanic output for the eruption in Iceland? I've always assumed some of the weirdness with the persistent blocking around 2009-10, 2010-11 was tied to the high latitude eruptions up there. https://en.wikipedia.org/wiki/2010_eruptions_of_Eyjafjallajökull The good news for December is that the temperature correlation nationally looks much less like the -PDO. That's not surprising, the PDO correlation to US temps is weakest in December and March. It's the pretty classic "record Nino 4 warmth" look. It's a correlation of course, so it always comes in a different flavor. I certainly had the US colder than it's been in December, but the relative pattern of hottest v. coldest locals are at least right on my end. We should see more cold expansion in the West with the next wave of wet systems over the next week anyway.

1/6 done with Dec-Feb, and two thirds of the US is +3 to +12. Nothing like 2009 despite months and months of similar forcing maps on here. At a hemispheric level, Alaska has been fairly cold, while nearly all of Canada is running +7 or more above average. Mexico has been fairly cold in the Central Highlands. I mentioned in my outlook that they might have a pretty cold winter down there. Still not expecting any part of the US to finish more than 1F below average for winter, as I had in my outlook. I had the +/-0F line about half way through the yellow area below in both the SW & SE US.

Precipitation pattern globally in November looks a bit like the MJO 5-6, but really more 6 or 6-7. My view of the MJO is the dominant feature sets up in the middle of the warmest band of the ocean. The waters are not an indicator of the transversal. Just where the heat is in aggregate. Phase 8 is pretty tied to precipitation patterns in Brazil - so the opposite phase v. the eight on the map is a good indication it was more 6. MJO isn't really the pattern driver anyway. To me it's like a dog on a leash. Everything else is the dog's human. The human has the dog on a leash, but at any given moment the dog can be left, right, ahead or behind the human. I had mentioned in my October Winter outlook that a blend of 1951, 2004, 2006 precipitation patterns in the Pacific looked a lot like the winter depiction on the Canadian. That held up fairly well in November, which is a good sign for the tropical precipitation verifying in phase 6-7 overall.

The special characteristic of 1973 from my research is the recurring volatility of two long lived patterns during short periods. I'm just saying...you'd have more chances than you think. The variation is so fast and dynamic the monthly indexes are almost irrelevant by month. You can see a pretty clear 45 day-cycle of cold reaching the east in that pattern. Early January, late February, early April. You can also see a 45-day tendency for super heat in the East as well- late January, early March, late April. AO was overall positive in Jan-Mar 1973...but you know...still pretty damn cold at times. Apr 16-30 was also very warm in the East, per the pattern.