https://max.nwstatic.co.uk/ecmimages/20140923/12/ecmt850.216.png
ECM's been thinking of the same time of year in 2011...
http://www.wetterzentrale.de/archive/ra/2011/Rrea00120111001.gif
http://www.wetterzentrale.de/archive/ra/2011/Rrea00220111001.gif
Striking similarities, really. The HP is being modelled as a stronger feature this time, though.
UKMO seems to be the only other model heading along the right lines for such an extreme version of events. GFS manages a prolonged affair that takes until a week into October to break down, but it lacks the intensity that ECM has produced.
JMA gives the high pressure a bit of trouble as the jet is particularly strong on the model's 12z op run. The way that the various disturbances phase into one very deep system is something GFS has trended away from over the past few runs.
GEM develops a small tropical system on day 4 to the SE of the Azores, which has no support from the other models. This causes the ridge this weekend to nose further north than would otherwise occur, resulting in a HP cell to our NE rather than E. That's more like what ECM was showing until yesterday. GEM then goes mad with the Atlantic jet... it ain't pretty.
Overall, ECM and UKMO are standing firm with the idea of strong HP influence leading to something exceptionally warm that gradually destabilises, GFS has trended towards them, JMA has stuck with a stronger Atlantic influence that keeps the NW more changeable, and GEM... has been very much in character.
I'm rooting for that ECM 12z op run, as I greatly enjoy such extremes in Autumn.
Originally Posted by: Stormchaser