The branch of the jetstream pushing down the N Sea gives up by Wed 1st with weaker W-E flow to N of UK while broad and strong jet develops across the Med. That northern branch persists longer than forecast a couple of days ago when I last looked, and the one from the Med weakens, too. Eventually the latter drifts north ca Fri 10th to run across the UK and continues so in a rather fragmented way to Wed 15th (but keep an eye on the really strong jet then leaving Newfoundland)
On the GFS this translates to Mid Atlantic HP with ridge to Europe Wed 1st, then slack for a bit with new HP over W Europe by Sun 5th with S-lies in place.This HP wanders around a bit with LP from Atlantic always threatening a breakthrough, but only doing so Tue 14th. The following day there's 965mb mid-Atlantic - being fed by the above jet?
ECM (sorry, 12z, haven't got time to wait for 0z today) brings cold air S on Sat 4th which GFS diverts further E, then develops the HP as above but with ridge to Iceland so although we get S-lies, N-lies are only just across the N Sea.
FAX also likes a brief N-ly incursion, but earlier, on Thu 2nd before new HP the next day
GEFS like yesterday, in S temps recovering to seasonal norm by Sun 5th then mild (very mild at first) for majority of runs. Dry then more chance of rainfall from Wed 8th. Similar in N, but temp runs diverge more and rain possible a day or two earlier. Not sure where the rain is coming from, looking at the synoptics. perhaps some runs do achieve an Atlantic breakthrough.
War does not determine who is right, only who is left - Bertrand Russell
Chichester 12m asl