I'm leaning towards 1.11-1.13 given we get the same or better station coverage and there is no government hutdown

@Rhhgdd Looks good.. On the high side for my end as a center point prediction (~1.135), but I haven't looked at the spatial anomalies to see how if there are any particular areas where data availability might bias it.... (Also the Jan month model is one of those that have a fairly large ERA5->gistemp correction in my linear model)...

the AO trending neutral at the end of the month is likely the main contributor to the return to warmer temps. At the moment I would discount the climatological rise for the second half of Feb for the moment given the more recent, albeit speculative SSW forecasts ..

Holding fairly steady, so I don't understand what polymarket is up to... looks quite a bit mispriced for the last few days ... Maybe someone has developed a better model based on the incomplete data to be expected and how it will bias? That or the biggest bettors are leaning heavily on a statistical model? The latter seems unlikely based on Polymarket's track record but I don't know who is responsible for the current pricing....

Recent errors for short lead times for the superensemble haven't been particularly bad. With 6 days left, despite models being on slightly the warm side (fairly usual performance), even a average daily conservative error with respect to ERA5 of -0.03 wouldn't amount to a change more than -0.03*6/31 ~= -0.006 C, which wouldn't anywhere near account for the discrepancy between our center point predictions and Polymarket's implied one.

Are we expecting Jan26 release to be same as NOAA's? Feb 11

@Rhhgdd no official schedule but yes (barring data problems!!; from my understanding H.R. 6938 passed with strong support and should be signed by Trump next week I guess? So they shouldn’t affected politically by any February shutdown which is in the 20% ish range?)

Last month the superensemble did exceptionally well as far as consistency (a std dev 0.016 over all daily center point predictions made from Dec 3-), especially considering I'd rank December as the 4th hardest month to predict for these type of questions (i.e. Mar, Jan, Feb, then Dec).

Based on my own outlooks from looking at forecasts for the last month I'm going to speculate and say most of this predictability was driven from the abnormally warm November temps in the NH coming into December, and the stability that it bought as far as in the NH decreasing the chances of disruptions to the jetstream (strat. polar vortex only stretched/displaced and didn't split), with less, and shorter blasts of Arctic air. Hard to say if it will continue, but it looks like for now its more of the same for January so far based on the ensembles, with a repeat of a stretched/displaced PV at the moment.

I take it as a good sign that the mean anomaly EPS/GEPS generally agree on the 500mb setup for the NH at the end of their forecast, even if there is likely quite a bit of variance within the ensemble (looks like more in EPS than GEPS).

Per the superensemble, if its anything like the last couple years and with a El Nino predicted, we might reach the minimum for 2026 before the middle of January.

Not had great consistency between runs in the ensembles, and my estimates for Jan's temps have mostly trended downwards since the beginning of the month (by about 0.025 C over the last 7 days) as the mid-month dip has deepened and continued to remain flat for an extended period.

The polar vortex starts getting disrupted and stretched over the next few days, but its supposed to strengthen back to above normal before the end of the month ..

Looks like it will return to normal around the 21st...

Based on climate priors for January, should expect some small warm up for second half of month, but given that week 3 is flat at the end of the medium range ensembles this doesn't look it's going to be the case this time....

2011 was closest recent prior for Dec 2025 that also had a small warmup, but at the moment 2022 looks like a closer analog for Jan given the medium range ensembles and the state of the La Nina, especially if the vortex becomes stable again as forecast.

EPS/GEPS are showing greater cold anomalies across Siberia from this scenario with more stability shown starting week 4 of Jan...

Not alot of strong agreement though generally within the ensembles, as the PNA becoming neutral though at the end of week 3 in GEFS indicates its going to be hard to say how much of the cold weather will remain locked up in the Arctic for the end of the month for North America... However continuing my aim last month to be more agressive earlier on in the month I'm going to lean more aggressively now towards what the medium range ensembles are pointing towards at the moment.

In the next week forecasts look like continued disruption to the NH jetstream resulting in more cold blasts for North America, and the last few runs in EPS/GEPS have shown a high developing over the Arctic afterwards for the remainder of the month, resulting in the cold Arctic air dropping down over Russia, US, Canada for the last week of the month; apparently this is a rare scenario....

Given that there hasn't been great consistency among runs this far out its hard to have great trust this specific scenario -- the jetstream weakening over the Aleutian islands and the high there shifting poleward.

~

Looking back to the first few forecasts from the beginning of the month it looks like I have done fairly poorly in my expectations for week 3 (much more disruption to the jetstream than I expected and troughing for NH, yet also fairly sustained cold temps for Siberia ).

looks the forecast high over the next week over Russia is a good 1-2 std dev above climatology....

It seems the anomalously high temps in the Arctic especially, but also China, the Sahel, and southern Australia are reasons for it not remaining flat for the last week and why we end up with a forecasted rise after week 3.

Depending on what shakes out, the drop in temp for the 2nd half of the month is on track to becoming around the 4th or 5th largest drop (from 1940+) based on what various adhoc metric you use (i.e. relative to the first half of the month, or relative to the mean of a shorter window from a few days prior)...

After trending lower until 4 days ago (inits until 14/00Z), the ensemble runs (15-18/00Z) have trended higher over the last 4 days for the end of the month, with the start of the warmup happening from the 26th onward.

Examining the det. models and the ensembles for the runs of the last 3 days it appears there is a trend towards a weakening of the MJO towards the end of the month as it moves into phase 8.

Given the increasing trend in global temps over these runs now ... I don't think I should be more aggressive than I am now....

So if it shows +125 , it would resolve 1.2450 or more

@Jack1 Correct (unless they change the base period or something)