Cheshire Freeze

No, I was thinking the same thing Nick. GFS very eager to push the vortex back east in the extended range. Now if this happens we don't want to be in a situation where we're caught with our trousers down, so to speak. We want one or the other...the easterly or a flatter pattern which amplifies again later on for the potential of N Atlantic ridging. The 18z is a blend of both and we end up with trapped Euro heights. The push back east of the vortex is not an issue however if we get enough latitude on that block out E. The eventual outcome in this instance would likely be a retrograde of the blocking.

Massive ridge exiting stateside!

Even more reason to be cheery tonight... Vortex lifting out of Canadian sector in to the 200+ hrs timeframe...USA very warm. Both things usually a precursor to an interesting time in the UK

We don't need serious upgrades at all. We're talking fine margins of added amplification in the initial stages of that HP being dragged NE. Minute changes to this will manifest as large scale changes in what we witness on the ground further on.

One word...painstaking. We need to squeeze just a little bit more initial amplification to get the high carved at a better latitude. Still, an improvement on the 12z run

Thursday night into Friday is looking best for my location, showers potentially becoming slower moving down the Cheshire gap too. Places that were having the showers during Thursday daytime would dry up as the shower distribution pivots and pushes them further into the W Midlands.

As has been pointed out, fairly major differences at 162 hrs...though not totally akin to ECM just yet! Ridging further N and that little low Nr Svalbaard has gone which will be of importance later on

Without a shadow of a doubt you can move that box 30- 50 miles N

GFS control is very good considering the back drop of this morning's operationals and about as good as we can hope for IMO 240 hrs...

I said last week that the way this winter has gone I'll be happy with just seeing snow fall. Euro heights back firmly in command in FI...could be a long way back from here

Advice: make the most of the end of the week. However, even the GFS introduces a mild sector making it marginal....

That is not a true NW'ly though Dancer. If anything that's a W'ly for the west mids (remember surface winds are slightly backed in relation to the isobars). This is an example of a true NW'ly...unfortunately a day later when the best of the instability has passed and pressure is rising from the west... Depending on the progression between Thursday day and this chart Fri midday, I MIGHT be ok in my location if we can sneak more of a NW'ly element for longer overnight Thurs. I fear for people any further S than me though- they may see nowt.

Definitely the scope for a slightly higher latitude block within that ensemble mean...

I can't disagree mate...I've seen it all too often in the last 10 years. Leads to heartbreak here as locations literally 10-15 miles away are buried. No idea why we can't just get a proper straight NW'ly anymore. The ECM and UKMO aren't digging the troughing a far SW as they were yesterday which is why the NW'ly gets flattened off to more of a W-WNW'ly during Thursday day. As it stands, we have a 12 hr window to get a streamer set up under ideal circumstances (uppers, wind direction etc). If I get nothing out of this, I am literally going to throw the pram, let alone the toys out of it.

Some of you guys in the W Midlands are going to be sorely disappointed unless we can get the flow more straight NW'ly earlier...I also include myself in not being in optimal position. The issue is that peak instability through Thursday afternoon coincides with winds being too WNW. Great for the likes of Greater Manchester, Stockport and N Peak District etc. We have to pin our hopes on Thursday evening through Friday am with a Cheshire gap streamer setting up to send snow right down into the heart of West Midlands. This is the sort of wind direction we should be aiming for....unfortunately instability has died off somewhat by this time This compared to earlier on Thurs when the winds are WNW...

6PM Thursday until 6AM Friday looks like optimal window for here...for others in the NW it will start earlier as winds will be WNW'ly- ideal for Lancs and Gtr Manchester. Luckily for you guys, peak instability will occur in these earlier timeframes i.e before 6pm on the Thurs so thundersnow may be a possibility.

Can you link me to those charts please?

We'd be relying on the HP pulling out west again- but when you're relying on upstream to play ball, you're dancing with the devil. ECM 240 hrs looks like we would see a rinse repeat scenario but I'd rather not chance it at all and just get the HP at a more favourable latitude in the first place! You can see from the day 10 ECM chart, it wants the vortex aligned N-S across the polar regions. We need to take advantage of this whilst we are in a situation which doesn't favour Euro HP sat around for too long. In reality HP cannot sit across Europe for too long in that scenario- it has to squirm one side or the other of the N-S aligned vortex.

The one issue I have, as shown on the ECM tonight, is if we don't get enough latitude to that ridging we will eventually end back at square one- low heights over the top will eventually overwhelm that high and it will be pushed back into mainland Europe.

As long as that flow remains west of N, the cold uppers over the Irish Sea should promote shower activity down into the west Midlands. Even when heights rise from the west this is the case.

@Steve Murr will love the last frame ECM... Snow piling into Kent on that chart.

-10 just clips the N coast

The continuity between the 12z and 0z to day 7 is excellent...though that doesn't make the output correct. I'm wary of the GFS output. Will view day 8 ECM then off to bed! EDIT: it's cold Night!

GFS looks to be out on a limb at 120 hrs...ECM, like the UKMO, has the troughing pushing further S&W Different profile around the Greenland area to GFS too ECM and GFS chalk and cheese at 144hrs ECM closer to UKMO. If GFS is wrong going forward, pretty much the whole 0z GEFS suite is going to be wrong too based on the ensemble graph I posted earlier. Guess we'll have to wait and see where the rest of the ECM run takes us.

Wow, the 0z GEFS are brutal...not brutally cold but brutal as in how many of the individual perts raise pressure again to our S after the cold snap Almost unanimous on a warm up (at the 850hpa level anyway) About 2 (poss 3) perts go on to produce a Scandi high at day 10. Pretty slim odds that the ECM will maintain its output of previous runs on the 0z I would think. I'm going to keep my fingers crossed the end of the week snow window doesn't shorten any more and go out and make the most of any snow that does fall from the sky. It may be the last this winter...you never know.