A record global mean surface temperature for 2027 is a shoo-in and likely to be in excess of the critical 1.5C above the pre-industrial era before dropping back in 2028

https://climatereanalyzer.org/clim/sst_daily/?dm_id=world2 

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world 

The record El Niño is, of course, manna from heaven for climate sceptics. I can already hear the pencils being sharpened for 2037 and “virtually no warming in a decade” global warming hiatus. 

El Niño is already showing up in a very slow start to the Atlantic hurricane season, Peruvian floods and landslides, and Central American drought. Too early for the next one - flooding in the East African short rains - but I’d expect those to start early. 

Then we can look forward to: winter flooding and an epic surf season in California, more Peruvian floods, Brazilian drought, Indonesian wildfires, Australian drought, South African drought.

Yes, all of this. But with a rather large question mark due to the likely unprecedented strength of this El Niño.  Is it sound merely to extrapolate from past major events, or could the significant additional forcing produce some different (worse) outcomes?

I’m expecting all the canonical El Niño effects to happen in a cleaner format this year because the strength of the event will overwhelm other modes of variability (like the PDO or IOD). So I’d say it’ll be more rather than less classic El Niño.

What’ll be interesting is those regions that are affected by ENSO teleconnections but usually more directly effected by one or more other modes. Notably the Indian monsoon (driven also by the IOD, Eurasian snow cover, various other variables), and Sahel rainfall (primarily driven by the AMO but influenced by ENSO - El Niño usually making it drier). 

This summer’s Sahel rainfall was average or a little below despite the longer term wetting trend, associated with climate change and the positive AMO. Might that already be a Nino signal?

And our winter weather up here. Could the strength of this event leave a bigger mark than usual? I’m already expecting a washout summer 2027 based on precedent from year 2 Nino summers. 

A severe drought in the Amazon rainforest combined with wildfires and exceptionally high SST's both inhibit sequestration of CO2 from the atmosphere and of course wildfires add to emissions. 

Yes, I was mentioning tipping points to someone a few days ago, in terms of increased warming leading to more and bigger wildfires which in turn release yet more CO2 into the atmosphere.  We mustn’t even mention CH4.

Given that, I think I would point to at least one exceptionally mild month this winter. Perhaps it will be January's turn? We've actually not had a remarkably warm January since 2007, so it's bound to happen eventually. Then again, the weather is good at throwing curveballs, so it's far from a foregone conclusion...

January 2007 being, of course, an El Niño month too. (As was, whisper it, summer 2007).

I think the biggest 'driver' of El Nino type weather on this side of the Atlantic is an increased 'southern jet' over the southern US. If this were to have any effect, it would be to amplify the developmet of low pressure systems over the Atlantic more south of thier 'mean' position. Of course, that is just speculation, but as you say, it does lean towards the idea of a wetter, milder winter... but, if strong lows dive even more to the south, then the reverse could be true. (late Autumn - Winter 2009/2010) being a possible example. 

From my POV I hope for that outcome - it'll have been 6 years this winter since the last snowcover here!

Here's an historic Grauniad article - 2015 - The Covid lockdown was 2020.

Weatherwatch: ‘A green January makes a full churchyard’ and other proverbs

https://www.theguardian.com/news/2015/jan/05/weatherwatch-january-proverbs-forecast-weather