raindancewx

We're entering the part of the pattern now that can produce snow and ice storms in the Southern Plains. My window for that was 1/15-2/15 this winter, its part of the cold retrogression into the Plains from the East. You can see the models starting to pick up the potential for these systems in the long range now. That's pretty much how I imagined it - big highs western Canada, storms moving east via Utah, picking up STJ energy as the La Nina dies.

GFS has snow to northern FL again this January. So that's neat - 90 hours out. Setups like this are consistently showing on the models over NE Asia. Blues by Kamchatka south of Reds to the north. Should see some powerful and cold systems in the Southwest roughly 17-21 days after Jan 20-25. Works out to week two of February roughly. The blue over red look (-WPO) is gone for at least a while. Feb-Apr is when the +WPO is actually a cold signal in the West, strongest in March. By mid-Feb its mostly a CA/NV/AZ thing but it expands north and east with time. At some point the purples and reds over Canada should move down to the US over different areas. That +9F area Is not very far away from the -9F area.

I've been talking about cold retrogressing to the West with time in 2026. We're finally seeing it show up now. Will be curious to see how the winter finishes up nationally. We're running "only" +6F now for January, big improvement on December since we're already 150% of average for moisture this month. A lot of the NW is running +10-20 above normal winter to date. Its hard to believe some kind of nasty regression to the mean isn't coming with Western Canada still very cold. As the cold moves toward a more-centered West location and moisture picks up as the La Nina weakens/dies, we should slowly move into a regime of different storm tracks and more powerful systems. I fully expect large areas of the lower 48 to see most of their significant snows in Feb-Mar. Activity by NE Asia earlier in the month supported more western storminess very late month January.

The La Nina is almost over. The subsurface wasn't even meaningfully negative in Dec, definitely won't be in Jan. 0-300m down for 100-180W by the equator was only -0.03 in Dec, v. -1.20 in Dec 2024. It's night and day different. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt The eastern zones of 3 and also 1.2 are much warmer than they have been in a while. The rapid transitions out of La Nina to El Nino tend to be stormy in the West and we've seen that in recent weeks/months. The record warmth out here is more tied to the North Pacific, it's more of a leftover from last winter than a direct driver from this winter. Essentially the setup is nearly identical in the background for the north pacific, and since we've had near neutral conditions in the tropics, not a whole lot has changed. Once we get in Feb/Mar/Apr the subsurface warming will either peak and reverse or continue and that will shake up the pattern.

GFS has a snow storm down in the Highlands of northern Mexico inside ten days, from a system that looks almost tropical. Saltillo ish area would see heavy snow if it were to verify - pretty neat to see even in fantasy land. NE Asia by Kamchatka has seen a lot of rex-block style setups this first week or so of January, which supports a return to active weather in the Southwest at the end of the month, in the Jan 25 and on range, roughly.

The subsurface rapidly warming in the cold season tends to correspond to colder periods out here. We should have an actual, real, cold day locally tommorow - in line with that idea, and the observed rapid warming. High of 38F/low of 19F forecast for tommorow. Already seeing rain transition over to snow. It's actually kind of neat that we're still getting snow in this pattern since we're literally running >10F above average winter to date (Dec 1-). Month to date, as in December, the greatest warmth relative to averages is found in the Northwest (+15-20F so far). We're already just about at/over average precipitation locally for January as of 1/8. We're already above Nov-Jan mean precipitation too. I've seen people liken the winter to 2017-18, and the warmth concentrating in the West so far is a bit like that. But precip is very different - we went 96 days without any measurable precip here from Oct-Jan in that winter, and went from Oct-Feb without 0.1" total at one point. This is a much warmer, but much wetter (better) pattern for the West. I still expect January to see the beginning of a cold retrograde to the West, but everything has been running a week later than I expected. The relatively widespread eastern/plains cold I thought would come in wk1 January is showing up for week 2/3 in the CPC 8-14 outlook (with 2022-23 showing as an analog each run). That cold should settle in for a bit and then retrograde West in late January and especially February. Locally the MJO/harmonic storm cycle seems to be ~48 days this cold-season, ~early Oct/late Nov/early Jan so far. So I'd expect more decent rain/snow events here in late Feb/early Apr before the pattern breaks.

January already looks like a much better month down here - seasonal snow levels and multiple systems coming through later in the week. My ACE to La Nina thing implied ~26 days in Nov-Feb would be 5F or colder than daily averages even after the late hurricane season activity. We've had 0. So either its completely wrong, or super back loaded. Right now we have a high of 41F forecast at the end of the week, which is 6-7F below avg, and a cold low is likely too. For all La Ninas since 1950, it's almost never out by more than 20% either way. Even getting to 20 cold days by Feb 28 would mean half of remaining Jan-Feb days will be pretty cold - very different from our +10F Dec and warm Nov. Analogs in the 6-10 day for CPC include 2018-19 and 2022-23 which are two years I expect to be become much better matches as the pattern progresses. There was quite a bit of activity by Kamchatka (Lows) in mid-late December, which coincides with stormier/cooler weather in the SW at 17-21 day leads. So we're on schedule in that week two January period.

My idea for December was a very cold and a very warm period - worked pretty well.

I'll go out on a limb and say that I expect a pretty wet period for a lot of the West in January. I believe that's part of the transition out of the current pattern. CFS is pretty wet nationally for the US - something like 2/3 of the country is depicted as wetter (and warmer) than last January currently.

Here is the warm up no one thought was real - definitely verified as a much warmer period.

Look familiar? This is Dec 1962, 1964, 1975, 2010 warmed up two degrees. Core heat Northwest, not Southwest. Core cold Lakes/Mid Atlatnic, not Northern Plains or New England. I just picked the best temp matches in the -PNA, -WPO, -NAO, -ENSO set. These are all warmed up by 2F - still supports my idea since Sep/Oct of cold eventually retrogressing to the West.

By the way - this is the -ENSO (La Nina/near La Nina), -PNA, -WPO, -NAO composite for December since 1950. Its very similar to the pattern this month, but less extreme. The pattern this month has the cold/warm areas in the same place, just need to add at least 4-6F to both the cold (colder) and the warmth (warmer). In the composite, January is still pretty cold. But you do see the cold retrogress hard to the West - in March. February is not coherent - its all over the place. -NAO if it continues becomes a pretty strong cold signal further west later in the winter, particularly Jan 15 and on.

Subsurface decay is way ahead of last year. Doesn't mean we go to El Nino. But the warmth below the western tropical Pacific is advancing east and toward the surface pretty steadily.

This is a look at what the month looks like to date. Had the right idea blending 2013/2024 - Jan 2025/2014 doesn't look too different from month to date, but there are hints of changes by Alaska. I don't think the overall look of the pattern will collapse for a bit. But positioning of the key feature will migrate slowly in January.

December is more or less going how I expected, although more extreme. It never really looked like some consistently super cold pattern. To me it always looked like a pretty cold start and then a much warmer push back. Most of the country may actually finish warm. Locally we've literally never seen temps over 65F from mid-Dec to mid-Jan, so this level of warmth is pretty historic here and definitely more than I expected. The Northwest is actually warmest relative to averages, which is not really consistent with -WPO, -PNA historically. It's just an ugly, unstable and volatile pattern. Record cold all month...oops My big theory theory is very simple: eventually La Nina Climatology kicks in. If you retain the cold in Canada, but add in the ridge over the Southeast in Jan and/or Feb and/or Mar, the cold will dump into the West eventually. Alaska and Western Canada are usually a good source region for us, especially if the La Nina / -PDO are to collapse late toward an El Nino or +PDO. I wouldn't be surprised if it happens a bit later than I initially expected though given how everything has gone to date.