[Model Output Discussion - Colder but how cold and for how long?]

2 hours ago, booferking said:

Can't see anything wintry until after mid February atleast the modo this winter has been a delayed response once we first start seeing in the charts a 15 day lag or so enjoy the chase leave but I'd leave it a good week or so meanwhile watch out for these nasty buggers.

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. 

[Autumn & Winter 2023---2024 Stratospheric Polar Vortex. Events, Analysis, Discussions AND Outlooks]

2 minutes ago, bluearmy said:

I think too much emphasis is placed on the reversal at 10hpa/60N regarding consequences. 
if we had a  strong sustained  reversal at 65N then we would expect some positive consequences for the mid latitudes over the following month (with downwelling waves if they propagate ). A tech ssw isnt a magic bullet. 

we’ve seen repeated notable reversals above 70N last two weeks and these continue up till around the 21st.   Would be amazing if these didn’t have consequences in feb but our worry is that they mean the wintry patterns don’t  get far enough south.  think west based neg NAO as an example. how many times have we seen the retrogression take the blocking west at a latitude that’s no good for nw europe ? 

hence my earlier comment about feb possible being a v frustrating month, 

 

 

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 

[Winter 2023/24 Chat and Discussion]

13 hours ago, SunnyG said:

I was replying to someone who, like me, likes mild weather.

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

[Winter 2023/24 Chat and Discussion]

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 

[Autumn & Winter 2023---2024 Stratospheric Polar Vortex. Events, Analysis, Discussions AND Outlooks]

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  

[Model Output Discussion - Colder but how cold and for how long?]

5 minutes ago, Don said:

I know these change a fair bit, but the EC46 does seem to be continuing to back away from its idea of HLB in February.

 

 

5 minutes ago, Don said:

I know these change a fair bit, but the EC46 does seem to be continuing to back away from its idea of HLB in February.

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

[Met Office and BBC Weekly/Monthly Outlooks]

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 

[Model Output Discussion - Colder but how cold and for how long?]

1 minute ago, January Snowstorm said:

Ireland is already under milder Southwesterlys by Thursday night. The mild weather seems to be coming about 12 hours earlier than was predicted this time yesterday. Quite the change out West

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

[Model Output Discussion - Colder but how cold and for how long?]

3 minutes ago, Captain Shortwave said:

A pretty potent northerly is about to affect the UK with the -8c isotherm covering most of the UK by tomorrow afternoon.

 

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.

[Model Output Discussion - Colder but how cold and for how long?]

6 minutes ago, Kasim Awan said:

Correct there is no indication of anything cold in the next couple of weeks bar the odd polar maritime spell. 

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.

[Model Output Discussion - Colder but how cold and for how long?]

18 minutes ago, BLAST FROM THE PAST said:

But look at this profile for the US….I anticipate the jetstream to suddenly ‘unfire’

 

Going to be a very interesting week of model watching

BFTP

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

[Model Output Discussion - Colder but how cold and for how long?]

2 minutes ago, blizzard81 said:

I noticed that too. Don't know if that's a good thing or a bad thing though. It would suggest increased mobility and zonal flow and less amplification which isn't good. 

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?

[Model Output Discussion - Colder but how cold and for how long?]

8 minutes ago, Met4Cast said:

I'm talking about the warming in early January, not the Canadian warming in December.

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 

[Model Output Discussion - Colder but how cold and for how long?]

9 minutes ago, nick sussex said:

So the bitter irony and one we’ve seen before is the strat warming turns up and messes up the blocking by moving the PV .

 

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 

[Model Output Discussion - Colder but how cold and for how long?]

5 hours ago, Continental Climate said:

By 20th of Jan its game over. We are down now to a 4/5 day cold snap. How can it collapse so quickly? 

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.

[Model Output Discussion - Colder but how cold and for how long?]

11 minutes ago, Eagle Eye said:

How many times do i have to say this. Maybe but it's hard to get a prolonged period of cold even with a major SSW, we're about to get one w/very weak surface response. We just had a reflected wave enhance the Greenland high, w/out we might not even had got it and that was a byproduct of the minor SSW. It was just that we're still in a transient signal period because of the north Pacific signal. A displaced or stretched and zonal link is not a 1 to 1 link, we're not in a zonal set up because of the minor SSW but because of some slight changes in the north American setup combined w/the Alaskan high. 

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 

[Model Output Discussion - Colder but how cold and for how long?]

8 minutes ago, blizzard81 said:

That was always my biggest fear about this particular warming. I think you're right unfortunately. You couldn't make it up could you? 

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

[Model Output Discussion - Colder but how cold and for how long?]

Just now, Purga said:

Ugly - with a screaming jet right over us.

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.

[Model Output Discussion - Colder but how cold and for how long?]

3 minutes ago, blizzard81 said:

So many questions aren't there? How could there be such a complete 180 degree flip? Especially as it goes against those background signals. 

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

[Model Output Discussion - Colder but how cold and for how long?]

3 minutes ago, Rocheydub said:

I'm not so sure why there is so much weeping and gnashing of teeth here, models with egg on face etc. These are super computers who do not compute embarrassment or emotions. The computers picked up the long wave signals a good few weeks back and stuck with it generally speaking. That's all we can expect from those distances and I think they did superbly well at that. The micro and macro scale of 2 such tiny islands in the grand scheme of things is nigh on impossible to get 100% correct at these big time differences. If you're not aware of the phrase "if a butterfly flaps its wings" then I suggest you google it. Chill pill. It's only weather after all. Worldwide life in our recent months and years shows us we all actually have vey little to moan about if a lack of snow is your biggest worry.

Back to the models. I'm not going to post the ECM 240 chart as it's on several pics up above, but I'm greatly encouraged to see the clear signal for the draining of low heights over Svalbard and Scandy. The would give us a quick enough route into another cold spell. I'll be keeping a keen eye on that area next after this week is over.

I'll enjoy this week, whatever it brings, I wish you all well in your chase. Whatever your weather desires are. But remember, posters here and the NWP super computers don't decide the weather, mammy nature does.  

Much love.

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. 

[Model Output Discussion - Colder but how cold and for how long?]

3 minutes ago, WolfeEire said:

It will be literally up in the air for sure!

Right now, all models show a mild sector in some shape or form. It shouldn't translate into a corresponding warmup at surface level due to a combination of factors. It would make conditions less conducive for snowfall wherever precipitation occurs. Looks like a second half of Tuesday episode. Turns much colder again Wednesday. 

[Model Output Discussion - Colder but how cold and for how long?]

11 minutes ago, Weathizard said:

Once you get cross model agreement on this kind of hemispheric set up it’s goodnight Vienna on any significant blocking or proper cold spell for at least a few weeks, unfortunate given some of the charts we chased this time last week.

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. 

[Model Output Discussion - Colder but how cold and for how long?]

6 minutes ago, blizzard81 said:

We just have to keep hoping that the ukmo is nailing this better than the other models but it is beginning to look increasingly isolated now. 

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?

[Model Output Discussion - Colder but how cold and for how long?]

31 minutes ago, mountain shadow said:

So, despite favourable EAMTs, MTs, GWO orbits, MJOs and a weak PV, the long awaited cold spell is now a cold snap with snow pretty much only in Scotland and favourable high ground in the North West.

Here's hoping 

 

23 minutes ago, on the coast said:

The big problem on here is so many posters want a 47/63 and are hyped up by long range charts. Until the expectations become 96 at max then many won't feel let down. As it stand's for the UK next week at the moment is looking very cold for most. Yes we don't get the snow but we do get cold. Moral of the post is stop believing past 120.

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

[Met Office and BBC Weekly/Monthly Outlooks]

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.