Bricriu

This is somewhat misleading. Prior to some past notable colder spells the charts suggested a long route to cold, but as those cold outbreaks proved it can happen quite quickly. Also sometimes the GFS Op run can lead the way against the ensembles. We saw this last week. The GFS is sometimes good at sniffing out trends that the other models don't pick up on. We could end up with heights towards the North East during the first week of February , but whether the high is far enough north and orientated the right way to advect cold our way I would be much less confident about.

But that's the key with a major ssw like we saw in 2018 there is more likely to be proper downwelling that propagates. Although the irony is that might have been too good as we ended up with a west based nao in the end, but alot of Irish People didn't mind as there was a historic Snowstorm out of it. An event that probably won't be seen again in our lifetime

I like Autumn like Weather in summer from a North Easterly wind. It too fills my heart with joy.

We had our first snow of this season this morning. Showers are few and far between ,though. We need a really unstable northerly for frequent showers down here

As someone said the weakest major ssw ever that it shouldn't even really be called one. I can't see us having a proper high latitude block in February as a consequence. From what the UKMO are saying I think we will have a mid latitude block to the east that starts to sink which let's the Atlantic back in through the back door. I won't be surprised if we see the ec46 change to a less blocked outcome. I will be delighted if I am wrong about all this

Very disappointing. A high in situ that just eats up more of winter. Still it's better than a zonal onslaught.

What's the betting the lower risk of milder interludes will be what actually happens again. Prior to this cold spell, they were saying there was a lower risk of milder interludes, then it changed from milder briefly in the south to what we are going to get next week

That's assuming the GFS is correct. Let's see what the UKMO and ECM say in the morning

It's just a shame about shortwave/ mild sector cutting off the colder air for a time. They would really do your head in sometimes. Still hopefully Wednesday and Thursday can deliver for Northern areas.

It has been well signposted that the last week of January would be milder. We are now looking to sometime during the first week of February for blocking to return. Will it be a repeat of this week or something better? That is yet to be decided.

Is your thinking that we could see heights rises to the North East being modelled later next week?

I thought it would be the opposite- the lift out of cold in North America would lead to a weakening of the jetstream and reduce the Zonal onslaught?

I know, but the Canadian warming stopped the pv from ever really getting go. It was the starting gun. It surely aided the January warming in further disrupting the polar vortex, even if it hasn't worked out as we want so far , but it may work out in our favour in February , if there is a reversal of the zonal winds on the 19th of January

But without the Canadian Warming would we have had the conditions in the troposphere that facilitated a high towards the north west to begin with? It's likely without it there would have been a strong pv in it's usual place anyway to perhaps override any other background driver

The absence of a major ssw. I got shot down for highlighting this but it lessens the chance of a messy and transient outcome. Without it we see our old Pal in Iberia spoiling things. The cold in North America doesn't help either,but the unusual warmth in North America during December didn't make much difference either. Sods law - if it can go wrong on the micro level it usually does despite the broadscale pattern looking promising for sustained cold.

A major one surely increases our chances of getting a sustained Greenland high rather than a transient one? I appreciate its not a guarantee of anything

We needed the major ssw. A displaced or stretched pv doesn't cut it as it increases the risk of a return to zonal.

There was a GFS run around 10 days ago showing the above chart or something very smiliar to this. It was scoffed at the time as unlikely, but now it could well come to pass. I suppose looking at it another way maybe that GFS fi chart showing a High in the Scandi area will be shown again in future runs.

I wonder is it a response in the uptick of zonal winds?

Well spotted. The GFS op in some recent runs has hinted at height rises in this area. As we know the GFS can sniff out a signal then drop it only to show it again later. Let's see does it pick up again in the days ahead Perhaps this will be the next direction of travel after the milder turn.

You'd be surprised, as I mentioned earlier, how dire output can change to something more favourable, especially given the chaos in the strat. Look up the charts for some noteworthy cold spells over the years, you'll see that in the days prior to some of them you'd never think a cold spell was on the way given the state of the NH profile.

When the UKMO is out on its own like this, it usually backtracks to the other models. Anyway I am going to try and keep Matt Hugo's post in mind regarding next week. It's going to be cold, and who knows surprises may pop up. When was the last time we had a 4-5 day cold spell in January?

You can nine times out of 10 believe post t120 if it showing a return to mild especially when that is backed up broadly by the ensembles. I don't care how unique the set up is. We are very unlikely to see a switch to extending the cold now. It's just a question of how long the milder turn lasts

When they mention a low risk of milder weather and unsettled in the extended that probably means we will end up going milder closer to the time. It was only a couple of days ago they were saying a brief milder period for the south which has now changed to a gradual return to milder weather seems likely.