Weather vane

Seems like a lot of detail to me.......

I understand some frustration at how the cold shots are getting delayed, but now we have GEM, GFS, and ECM all primed at 240hr for cold (GEM already cold). HP in GFS/ECM could sink but you'd have to say we are close to having a cold or very cold Xmas. Snow is another matter.

The GEM solution seems influenced by a a stronger lp forming off east greenland around 150hr, which pushes SE/SSE and overcomes the UK centered height rises to give an a more westerly plunge of cold into Europe which is what we need. That same developing lp occurs a bit later in gfs and ecm, has less punch, and rides more over the top of UK hp. So, an earlier and more amplified lp push from greenland seems the order of the day, at least for one cold solution.

Dunno about others, but I am the current scenario. How often do we get that GFS never-ending hp (and near constant shape) at our latitude at this time of year... hardly ever it seems (happy to be corrected on this). And I for one would not be betting on it lasting.. With cold diving down eastern Europe, hints of pressure increases in arctic.. what's not to love ! Yes, we could end up with a stationary hp, but I don't think it would take too much for a hp rise, NE or NW... fascinating so close to Xmas. Beats zonal every time..

At 168hr, Icon keen on a more southerly and SW incursion of the Icelandic low, which pushes the pesky Atlantic hp westerly. Would be a good development. Other models not in line with this however.

As others have said, a few bad runs today mean very little when we're looking at charts past 5-6 days. Why make conclusions on 8-9 day charts, over the promising 9-11 days charts the past 2 days? Both sets are not even in the semi reliable so still all to play for. Seems obvious, but small alterations in the many things I don't understand can flip the current scenario very easily.

I know, not a hope of verifying, but for sheer beauty, I couldn't help posting it...

Agree. Could be a timing thing. I feel its very small margins between the greenland high vs not and a flatter jet. I don't think it will take very much for other models to go the way of GFS, though a betting man would likely put their money on ECM/GEM. Nonetheless, I give the GFS a decent shot at winning out. Let's hope

The slightly more amplified situation around South Greenland 7 days out seems to be a key factor in preventing the NA hp from retrogressing north in GEM and ECM. If a little more slackness could build off eastern Canada at that timeframe, then we might be in business.

No doubt, exciting, albeit somewhat odd charts, at the moment. Plenty of routes to cold. Models struggling big time to figure out where the heights will go. At 240, we have ECM with Scandi heights, GFS with Greenland heights, and GEM kinda with neither. Where will it end up???

Ensembles at 240 very much in line with the uncertainty, though there are some promising charts in there for potential cold evolution at that time. .

True enough, though not necessarily the hp across Europe which has come after a very significant northerly plunge of the jet. To me, I thought that scenario could easily lead to further NW driven southerly dips in the jet, but not so.

The models have done a good job at forecasting the upcoming heights into central/NW europe, which they picked up on at least a week ago if not more. We often complain about the flipping and flopping, but there has been remarkable consistency with the incoming settled spell.

So much for that theory. Atlantic high back in charge by 240hr Although pressure low in SE euro land.

Is GEM on to something here? 180hr. Atlantic high stretching a little further north to stop Newfoundland low barelling across and flattening the jet. Allows jet to push southerly into Europe. Would be a nice pattern change not so far away. Prob all change in the next run...

Most GFS panel members over the past few days are showing a lot of support for hp in central/NW europe out to mid month. ECM also showing this for a few days. So, not looking good for a southerly tracking jet in the next 2 weeks unless some major change happens. Just hope a long lasting euro hp slug doesn't come out of this.

How often do we get high pressure at this latitude, at this time of year, stretching pretty much from Newfoundland to siberia ???

ECM, GFS, GEM all showing some effort to push colder air down on NW Europe at 240hr. Aftet that, GFS goes with mega euro high deep into FI (surely not !!!!). Let's hope for coldies that the NW trough push wins out over southern hp advancement.

and May....

I hear you ! As many others are saying, you have a good chance of near mid 20's at times next week.

Well, yes, it is definitely August ! Today's forecast high for London is 22oC, which is basically bang on the long term average high for London at this time of the year.

Helloooo, is that ridge getting the better of that low ???

It's clear from all the comments why it is difficult to predict snow in this part of the world. Why therefore do the models seem to constantly overestimate snowfall, at least for the UK/Ireland? Sure, they can get it right at times (BFTE 2018), but most of the time, the charts appear wildly out, and I imagine the verification stats generally make for poor reading. I would have thought the algorithms etc used for snowfall prediction would be more conservative for the UK, but maybe that's the issue, the algorithms are built for global forecasting and are not tailored for one particular region?

Thx for posting that great link !

Although for many this cold spell has been a bit disappointing, I for one have learned lots about chart interpretation, and the pitfalls of making conclusions based on a limited set of considerations. Thanks to you and all the other learned on here for that. Now back to what's happening out there - hoping the clash of atlantic and cold brings something interesting for Thurs/Friday. However, not sure at all if there will be sufficient cold left at the boundary for a very significant snow (ie, that which falls and stays on the ground for at least a day so we can have some fun !). Chart below is 850 uppers for Thursday afternoon.