Model output discussion - cold spell approaching?

[Eastbourneguy]

Evening all!

Models currently have a lovely time trying to resolve an extremely amplified meridional pattern, with trough disruption causing chaos.

Just look at how amplified the whole pattern is from North America across to Europe. 

GFS OP @+72

 

 

But then look how even more amplified some members like P16 are at the same time frame. The ridge into trough in the western Atlantic is distinctly more elongated. 

I've drawn arrows to indicate the potential trough disruption occurring, I think the one in the western Atlantic is most important here. On P16 the trough disrupts in the next 24 hours, cuts the low off from from it's fuel source of cold air, leaving it to weaken and meander around not doing too much in the Atlantic. This allows some retrogression of the the high to the east and the western high to build into each other in a favourable location, as seen in the below three time steps. 

By T+120 we have a new shortwave to worry about to the north of the UK but at least we have built a favourable high!

T+78

T+84

T+120

 

Contrast this with the Op run and with no trough disruption in the Atlantic by T+84, keeping the low fairly strong and preventing any retrogression of the high over towards southern Greenland. Then by T+120 the low has moved towards our southwest, dragging in south westerlies!

T_84

T+120

 

Other GEFS runs that have also have the trough disrupting in the western Atlantic are 7,9, 10 & 12 (probably some more too) and all lead to rather nice conditions for coldies following! 

This is of course without thinking about the trough disruption happening over the UK on Saturday and the cold high that is being very reluctant to move in mainland Europe!

Night peeps!

Edited January 14, 2021 by Eastbourneguy

[BlueHedgehog074]

Will be locking this now. New one up in a sec

New thread:

 

Edited January 14, 2021 by DiagonalRedLine