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I've been meaning to tweet my 2p on what we might expect from the NAO / Atlantic jet this coming winter.
And since November is nearly over, I'd better get on with it!
There is strong agreement between the dynamical models on NAO+. Where does this come from...?
And since November is nearly over, I'd better get on with it!
There is strong agreement between the dynamical models on NAO+. Where does this come from...?
Could well be the SSTs. Pic is the current SST anomalies compared to our NAO sensitivity pattern ( https://doi.org/10.1175/JCLI-D-19-0038.1, @HughScottBaker @ChrisEForest).
Warm subtropics in Pacific and Atlantic favour NAO+ (as does warm tropical Indian Ocean, though we don't get skill there)
Warm subtropics in Pacific and Atlantic favour NAO+ (as does warm tropical Indian Ocean, though we don't get skill there)
Some other factors (maybe QBO, solar) could favour the opposite, and the stratosphere is getting disturbed right now, which could be a sign of NAO- to come.
Certainly an interesting case, with some statistical predictions disagreeing with the dynamical ones.
Certainly an interesting case, with some statistical predictions disagreeing with the dynamical ones.
Altogether, I think I'll side with the dynamical models, as they show strong agreement and their skill tends to be highest in the multi-model mean - https://doi.org/10.1029/2018GL078838.
What would this mean if it comes true? For the UK a mild winter overall, likely wet and stormy as well...
https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/ens-mean/nao-description
https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/ens-mean/nao-description
