SMU

It wasnt the best but the operational goes off the AO scale 18z

NB The increase in Higher pressure over Greenland in the 10 day means for 18z

Look forward to some more of these runs cropping up this week

It means @144 over the pole the ukmos clarify is still 80-90% resolution where as GFS at the same time of 144 has plots articulated by a child

Hi the link doesnt exist any more plus the locale we would want to look at isnt on that small chart! Anyway evening All > Lots to be optimistic for tonight all detailed before the 18z Is this winter any different / Any usual synopics? well noticably after many years of the AO/NAO blend looking great in Nov then all of a sudden literally on the Dot the AO / NAO turn positive > Well so far this month the opposite has happened... Look at the first of December With the strong vortex we have been lucky enough to see low level blocking in the troposphere keeping the SPV from downwelling - infact the disconnect has grown stronger recently. In terms of the next 7-14 days can we continue that? - * Remembering the caveat that nothing in the UK cold wise is 100% Guarenteed * The models especially the GFS have perpetually underestimated the strength of the polar & Ural heights > some referring to it as the imaginary line is ironically pretty close, its more like the models resolution becoming clearer with time. To explain how bad the GFS has been V the UKMO for resolving polar heighst then the chart below sums it up well Or maybe the GEFS mean for 168 a few days ago for Sun 08AM now today for Sun AM Look at how we have hit the 'unmute' button from the GFS over the pole. So we switch our attention primarily to the Euros > In favour of the steady UKMO > then blend the EPS & Operational DET. Whilst the DET has been mild over the last 24 hours its drawn to the UKMO with the Link up of the pressure ridge over Greenland & the Arctic high > creating a tidal wave of cold spreading west rather like the troposphere in a downwelled SSW > Maybe the tropospheric response pre SSW. EPS mean now very supportive. Its now fairly odds on >80% that deep cold <Sub -16c / -20c will drop into Northern Scandi. NB the tanking AO from the DET & EPs in harmony together Currently then with the jet profiles from they are once we reach day 8-10 when that wave of cold is heading into Northern Europe the Uk will need to rely on a secondary phase of amplification to swing the cold our way..... Chances of a Strong cold spell into Crimbo around 30-40% which is much much higher than the usual <5% This is best chart of the night rotated > EPS mean day 15 S ** Expect the amount of cold GEFS ENS to significantly increase over the next 24 hours *

For example the control run- This makes UKMO very very good..

Hum... ENS increasing the polar heights all the time Incidentally the 4-5 GEFS that have a GH at day 9-10 are almost identical at 144 to the UKMO

The low will slowley shear apart so energy going east & West... GFS at 144 similar & svalbard deep cold alligned much better - could be close this run

Very positive UKMO tonight > 144 shows the -AO tanking, deep cold filtering out of the pole. All of the UK cold spells have come 3-5 days after this.. The run into xmas is looking exciting-

Updated ICON 12Z 120 > twin blocks over the pole forcing the PV to drain in the mid lats > troughing alligned favourably over svalbard > nothing like the last 10 years in Dec

Saw a pic of tirol today 225cms so far

Its the shape & viewpoint of the blocking over the pole > To bebin with a shout of deep cold from the East we have to actually have cold there which is stage 1 > Then the ridge to Greenland + atlantic nlock scenario is a well trodden route to cold day 10-12. Also the nearer term it keeps the atlantic at bay so a win win really.

Remember Scandi blocks can often be neutral or positive NAOs

Lovely crisp afternoon here, air drying out. Current temp 2.9c A slam dunk sub zero night here as long as the fog doesnt scupper my chances. Been out cutting the rear ferns - they were out of control as compared with the one on the right. Its taken hours out there. Ive trashed my grass as well

ICON now looking rather like the UKMO now!

Temp got up to 5.1c early now dropped back away to 4.2c

The 06z Mean at 168 > the 00z 174 mean Shows everything moving in the right direction at the right timeline * Svalbard troughing better alligned * Blocking more developed over Greenland * Atlantic ridge better defined

As ever in a *potential* cold scenario with some -AO blocking the GFS is creeping along towards what we want. As mentioned last night its latched onto the troughing over Svalbard sinking South & now increases the heights over Greenland East Its not a million miles away from the UKMO now...

UKMO 120

Good Eve- A quick snapshot of the 18z shows some subtle changes, these are becoming more noticeable with each run > the UKMO is if course the aspirational landing zone. * For the first time the GEFS mean has the svalbard trough which will be crucial down the line for getting proper cold into Europe. * The Scandi > Greenland wedge. GEFS still markedly all over the shop from 96> 120 however with each run the angle of the wedge becomes more acute, & as if this continues there comes a point where the ECM solution would not be viable - although the jury is out on this one in terms of can we make the leap to the UKMO solution * Atlantic energy piling up in the atlantic according to the GFS > however this push NE is still at 144 & within a window where the energy could spread out as dictated by the High pressure to the North. Much to ponder over the next 2-3 days as we see the dust clearing & still wiggle room potential away from the atlantic pushing in depsite the aggressive ECM / GEFS Mean....

Eve - so the ECM V UKMO have one big fundamental difference with Energy distribution at 144- UKMO being the most amplified has managed to get high pressure directly North of the UK & as a result the atlantic system is steered NW up west of Iceland > this same system on the ECM moves NE through the block bringing the milder air. There has been considerable change over the last 24-48 hours working in favour of a good outcome the UKMO has mileage, however so does the ECM + Mean Lets see what tomorrow looks like...

I saw a post on FB it was snowing on the chilterns

I would botley hill deffo has snow at the moment....

2.6c & Rain... Curtains twitching

Close but no cigar on this run > we need more heights over the top like UKMO 144!