bluearmy

In this country, cold spells are generally brief ........ getting a spell rather than a snap is the trick !

This gfs op run showing a closer tie to the upper strat modelling that the op and gefs have been showing recently ....

Gfs undercutting in fi could be a retrogression later on aswell

Gem builds a strong scandi ridge again ...... well supported by the se Euro trough with reasonable Atlantic profile going forward

Cohen speaks of an event next weekend and you reference events between 2 and 4 weeks .......... incidentally, Exeter speak of settled and cold I wouldn’t normally comment but some less experienced members may be confused

It’s not a surprise - infact I would prefer a snowstorm to be mentioned re the eastern USA as it probably means a deeper slower trough and more amplification ahead of it

Back end of the 06z gefs not so good re the return of the mean tpv to nw of Greenland by day 16 thats on its own isn’t a massive problem re possible scandi heights but it would keep the Atlantic busier than the eps/gems offerings

Housekeeping on the clusters there is a 50/50 split on the less amplified op against previous ops beyond day 10, these two clusters go to six again (max 25% support) so still no reliable guidance

Or not at all .............. Seems more than feasible that an ssw isn’t required this winter to bring nw Europe some deep cold

Somewhere inbetween ..................

seems that the obvious trend is that the ridge won’t get the traction to sustain far enough north initially - what happens in the Atlantic subsequently dictates if we drive another bout of WAA to form a proper scandi ridge currently looking messy but pretty confident that a nw European high is pretty solid ...... likely to be cold one but how cold dictated by whether we are generally cloudy or clear there remain many routes on the table re how this ridge sets up through week 2 (does it settle scandi?) and the puzzle solved eventually by how much goes into the northern arm and how low heights over se Europe are able to drift west. the Atlantic jet in the extended continues to look pretty weak and the mean tpv still centred ne Siberia end week 2 on the eps. Glad Daniel got those cushions for my fence ..........

The means seem to edge the upper ridge a little further east, run by run. The ops keep building those scandi ridges but the truth may end up with a cold block over nw Europe ......... the amplification looks pretty certain but how that plays out for the uk remains very uncertain

6 eps clusters post day 10 ......looks a good picture at day 10 but the 6 options by day 11 show the wide spread that must exist across the 4 clusters at day 10 the mist is thickening up again ......... and with the gfs op losing the signal somewhat whilst it’s in the more reliable part of its output, I’m feeling pretty comfortable astride my fence !

Well it’s three ecm ops on the bounce actually ....... Interesting upstream on the gfs 06z op .....looking across the 00z output made me wonder how long a scandi ridge could actually sustain and whether we may not actually see griceland/scandiceland wedges or cut off ridges up there

Thinking back to yesterday, the gfs runs were very mobile in week 2 but because they got enough amplification in the crucial phase, the ridge gained latitude and the Atlantic undercut. The 00z op is trying but the pattern is too far to the east and it get overrun ....the para just doesn’t quite get it right in fi but it isn’t far away from a good back end to week 2. both runs have a different polar profile to gem and ec whereby the Canadian vortex begins to exchange low heights to Asia on our side of the pole - remember my posts early last week on this - unless you have a strong upper ridge already in place forcing split flow then that exchange over our side of the polar field is curtains for us to go cold in this phase. incidentally, my fence sitting staying 50/50 after yesterday’s output is predicated on the extended clusters over the past couple days really not running with a solidly wintry offering more than 15%. Whilst there are five on offer, only one of the five shows that persistence in the pattern ...... I’m waiting to see this increase - the eps are running to day 15 at a similar resolution to the gfs op to day 10. they are capable of deciphering a difficult solution. Once I see these clusters gaining momentum on a sustained scandi ridge with some split flow to keep it in place then i’ll be content to jump off that fence.

Clusters - only 12% go with the control .....there are still five in the extended so the message remains ‘wait and see’. The pattern in the 9/10 day period is amplified but the three clusters pre day 10 then look very unconvincing post day 10.

The eps control is a colder versions of the gfsp @feb1991blizzard - does the presence of the mean ridge on ecm T240 mean anything yet ??? despite the obvious swing seen today, I’m still 50/50 .........let’s see what happens as higher res picks up the difficult bits re phasing to our west and more amplification over n America slowing down the systems to allow the ridges to manifest themselves

At 600 feet up in west yorks, you can be more sanguine than most ! but you're right, the other thread is more relevant for model discussion which is based on the stronger likelihood of mobility verifying - that's just basic stats. if i thought there was no chance of cold within the next 2/3 weeks then i would be discussing the nwp on there and keeping knocker company!

this is never going to be an evolution where the mean will pick it up ahead of the ops …….too much volatility in the nwp

gfsp on board at day 10 - waiting for ecm to give a full house !

The jet should be weakening post day 10 as the Canadian vortex tends nw and the temp gradient becomes less steep as it drifts There will still be a nose of low heights into the nw Atlantic - given the Siberian blocking in place, this is why I feel a scandi ridge is far more likely than a greeny

Seriously Ed, you need to stop using day 16 op charts to make a point, whichever direction they are headed in ....... eps clusters are now five again in extended so the mist which was possibly clearing is maintained .... looks like plenty of possibilities at day 10/11 for coldies

Eps extended mean smells of binary clusters again ..... if not, it’s probably a swing away on the pendulum after yesterday’s 12z promise .......

It’s you ..........

Those extended clusters are interesting....... 50/50 on a fairly wintry scenario ....... now where have I heard that recently ................. that ‘wintry pudding’ maybe a little over egged but that 55% cluster must have a significant number of pretty decent members for coldies