Comparing today's GEFS line plots for Plymouth and London with those of the 12z output yesterday, has revealed almost no change as far as the number of colder outcomes at 850hPa is concerned.
Being at the 850hPa level, surface conditions won't always reflect this due to low-level modifications (e.g. a -5*C northwesterly is a lot less cold at the surface than a -5*C easterly), but it offers a reasonable guide to how GEFS are trending (or not trending anywhere, in this case).
The method I use considers the number of runs hitting various temperature thresholds and also to what extent the mean does. Inspired by Retron's ensemble watch of years past.
Originally Posted by: Stormchaser