As the charming DEW is still on his travels, I’ll have a last go at the model roundup in that style – I too am going on my travels next week (not with DEW obviously – I hardly know him …. your honour)
FAX – Current set up shows a triplex of low pressures in the mid-Atlantic 987mb, 996mb and another 987. These throw a complex set of fronts across the west side of the UK which will pulse rain along them from south-west to north-east. By the 11th the three parts of the Low area have split – one has gone down towards Iberia 975mb, one has gone over towards Denmark 995mb, one remains north of Scotland 993mb. Still southerly flow, still mild. By the 13th (end of the run) there are just two cells remaining off Iberia 884mb and Finland 981mb. These two provide an occluded front from south to north, with a mild airmass covering Wales and England; and a cold from coming from the north covering Scotland. Bit of a battle-ground forming when these two front meet. The next FAX will be very interesting to see how this develops.
GFS – matches the FAX over this period – low pressure dominated, with the duplex Low pressures to the southwest and northeast of the UK. North winds to the north of the UK, south winds to the south of the UK. Day time temps 5 to 10C in the north; 10 to 15C in the south. Overnight temps -1C to -2C in Scotland and generally -1C/+1C in England/Wales too. Yes – probably the cold is coming. By the 14th, there is an Iceland HP 1025mb in position and most of the UK is under Easterly winds – getting to -5C over Scotland and +2C over the south. By 19th there is a real north south split in overnight min with -7C in highlands, +7C around London. By Sunday 23 November the Iceland HP has dropped down into the semi-perm of the Azores High and the UK is on the cold side of the jet. Gentle LP crossing the UK 1005mb giving several rain ‘happenings’ – but this is getting into FI-Land now.
ECM at 120Hrs (14th Nov) is giving good cross-model agreement showing the two LPs – 985mb mid-Atlantic and 970mb over Finland; HP 1030mb just south of Iceland. UK under east/south-east winds and getting cooler. The HP from Iceland does drop down to the Azores, but it does it through a more circuitous route over the UK and Spain. By the 19th Nov, the UK is on the cold side of the jet forecasting low single figures and certainly rain, but probably that good old ‘wintry-mix’ in the north and on higher ground.
GEFS ensembles show very mild to 16th Nov, +6/+7 over 30 Yr mean, then a quick decline, now going below the 30-year mean. Noticeably good agreement for this out to 17th Nov, then the average does go down below the mean from 17th to 22nd. More rain spikes than a flowering cactus to 17th, then a dryer few days before more spikes from a smaller cactus through to the end (25th). Down south the snow row does give a 4 and 3 around the 20th Nov; Glasgow snow row gives 9, 4, 6, 8 over that time; Inverness gives a prediction of a potentially enjoyable 11, 18, 23, 14, 19 over 18th to 22nd Nov. The average is below the mean in Scotland from 13th through to the end of the run (25th), so the cold looks more certain there. Good luck guys.
ECM AIFS London, predicts daytime 14C for London and 11C for Glasgow on the 12th November; dropping to London 9C and Glasgow 3C for the 17th and by the 25th London overnight has +7C, while Glasgow is showing -5C. At the end of the run there are big fat 0 for precipitation; the earlier dates around the 17th there is only a little rain in the north, but more in the south.
Happy weather watching – the first chase is upon us, but a bit early to get carried away.
Dickieboy - In the deep mid-Wiltshire 85m ASL
Formerly Guest (16) since 2004