weatherguy

Here she comes

Fingers crossed I don't miss out on the snow compared to those further E/NE!

+192 - uppers mixing a tad, but that's more than fine, because this is what's causing it... blizzard conditions for many.

At 168 the perfect retrogression has occured: Siberian cold pool about to be resupplied....oh my.

Oh sweet jesus. +144 is a peach.

Unreal output. Utterly bonkers depth of cold heading our way! March 2013 was a wonderful event but was exceptional as there was no huge cold pool, just perfectly positioned pressure systems to deliver snow...this is looking an altogether different beast. Just hoping my move up north to Sheffield hasn't lessened the amount of snow I'll see from this!

A case of temperature scale skewing perceptions; it's always going to trend warmer when -15c is the main cluster in the reliable!

Messy 18z gfs which may not look appealing to some looking for "perfect synoptics", but the messy nature could provide quite the snowfest for many. Snow galore if this were to verify. @richardc1983 below - it's pointless going into specifics such as that right now. things can and will still change at this timescale; snow is notoriously difficult to predict at range beyond whether it is cold enough to snow. All I'll say is UK-wide snow is likely over the next week, going off current output.

I seem to repeat this every year when people are concerned about snow potential when milder uppers mix with continental air; there's no need to worry! Easterly air is drier, and therefore you don't need the -5/-6c uppers required for snowfall from PM air. In any case, this is really just splitting hairs at post t+200, as the scenario will likely be very different. In the meantime, excellent output!

Remember THAT ECM a few years ago? I don't have an archived chart to hand, but damn the current output must be strikingly similar, and at short range too! Look at that long-draw easterly! Hubba.

Extreme FI of course so just for a bit of fun, but the GFS 18z throws out this, erm, extreme chart at around the +360h timeframe. Wonderful HLB in place but unfortunately we still manage to catch the zonal maglev! In seriousness though, it's interesting to see a relatively persistent pattern of HLB blocking modelled in the longer range, should provide encouragement that something cold could be on the cards post-Christmas.

Good evening all, I'm back for another winter of cold chasing! I know the chart on the right is a beauty and (rightly so) is a stonker for what it could bring, but it's interesting actually looking at the current state of play - atlantic is remarkably quiet for this time of the year when traditionally we should be bearing the brunt of a zonal onslaught just praying for strat developments... It will certainly be interesting to see how the disconnect between the trop and strat vortices plays out. Current output highly encouraging stuff!

Not nailed on til it makes it to at least +372h IMO

12z left, 18z right. nothing if not consistent. By 138 we do see a somewhat better evolution however...more energy going under the block and eastward progression slowed, as the med LP sits further north. Expect a nicer run from here.

Yes Steve, you're bang on as per. I really do find it fascinating actually analysing the minor differences which can have such large impacts down the line - for every frustration, there's an explanation!

Incredibly fine margins, Lets take a look at the GEM against the ECM for the "perfect" run easterly. Here we see the orientation of the LP to our west at +72h making a key difference by +96h. Simply put, the GEM LP "squashes" more against the block and you get a greater negative tilt, which effectively spins the axis of the Scandy HP faster and rips that PV segment out over siberia straight for us. With a very similar set up shown on the ECM, this does not happen as sharply, and therefore things don't pan out in quite so extreme a fashion. This really shows by +120h. The orientation of the Scandy high is less favourable, and the PV segment isn't dragged along with it. Still a good chart for us, but nowhere near the "beasterly" of the GEM. Hopefully this rather simple explanation shows to the newer members how finely balanced these setups are for the UK, and how the models can "get it wrong" at such short range. Minor differences by +72h can alter things drastically by +120h when trying to get the elusive beast from the east to our shores.

Quite. +216h shows the enormity of the block, and an longdraw easterly flow being established.

Wonderful viewing, but as ever the caveat is that there is still huge divergence at close range, so it's far from being in the bag. Easterly setups are notoriously fragile for the UK.

Oh my...Wonderful. And height rises over Greenland to follow and reload the cold. Nothing resolved yet given the discrepancy between GFS/ECM at such close range, but it's nice to see ECM sticking to its guns.

I would urge caution looking at de Bilt. Yes any upgrades on temps there are promising, afterall that does signal the potential for an easterly, but fact is where there are such fine margins usually around how far west a blocking high will hold. I find this rather unhelpful when looking at the UK situation. Lets cross everything for UKMO.

Yes indeed, it would be very marginal as modelled there. Should have emphasised "could" - was rather referring to the potential for how it might pan out, something to keep an eye on anyhow.

Could be a sig snow event with the 6z GFS - highly likely there'd be some instability generated within that feature at short notice

Lets look at the comparisons between 12z GFS and ECM then out to 240. GFS MAR holds, northerly incursion, HP flattens, consolidates, another northerly shot, flattens somewhat, height rises towards scandy. We know how this propogates further down the line. ECM MAR holds, northerly incursion, HP flattens, less potent northerly than GFS follows reamplification (to a lesser extent than the GFS), height rises up towards scandy. Pretty decent agreement at this range to me. The real divergence appears around 192h, with the general pattern being the same. I'm sure the ECM solution would essentially be the same further down the line. Makes for good watching this

216 ECM looks like another Scandy high incoming.

1 word....BOOM! Anyone fancy some battleground blizzards?