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

[TillyS]

29 minutes ago, Cymro said:

 

For me the cold spell started on Saturday and will continue into next week. 2 weeks at least of below average temperatures in mid winter. Wonderful! 

I mean, strictly speaking the CET is above average. Has been well above average for the first third of the month: 

Met Office Hadley Centre Central England Temperature Data Download

WWW.METOFFICE.GOV.UK

 

It has felt really cold these past two days in the south, and in some cases and places has been cold, but empirically speaking not very. And temps are nudging upwards this week. So, no, not ideal ahead of the apparent snow event next week.

We need deep embedded cold. This isn’t that.

 

[kold weather]

30 minutes ago, bluearmy said:

Looking at the dogs breakfast that the nwp has become overnight, you begin to wonder if there will actually be a ‘northerly’ of any consequence away from Scotland ???

with the detached ridge heading se and the possibility that the shortwave could become a distinct feature, the Atlantic could then come in before we see any strong northerly flow in evidence for more than 12/24 hours at the end of this weekend into Monday. 
 

let’s hope that the fog clears somewhat through the day so that at least we get a new envelope in place (the old one needs chucking away) and that it’s got firmer edges! 

I couldn’t disagree more NWS - too much movement imo. What is the trend ? I’m really not sure at all. I did think I knew yesterday 

It's a total mess on the ensembles even on the macro level to be honest, complicated by the fact that relatively minor adjustments will make the difference between a 2 week exceptional spell and a rain event with a little snow for Scotland and SW airflow further beyond.

I think we can only hope it falls favourably for is, it's been a little while since we've really lucked in.

[TSNWK]

7 minutes ago, bluearmy said:

Icon 06z run is a small step away from more amplification with a smaller Arctic ridge and some phasing to our nw looking more likely as the greeny ridge closes up compared to the 00z run 

just one run though 

perhaps I should go back to bed ! 

on a brighter note, the chances of a surprise rise in heights as week 2 progresses like the pub run last night have increased imo 

however the 0 850 is at least 100 miles further south over Central France on 00Z it was northern france.

[Mike Poole]

17 minutes ago, bluearmy said:

I thought mike’s post was indicating that uncertainty has increased over the past three days. maybe I read it wrong 

Uncertainty increased further around day 9, reduced up to date 6 was my take.

Edited January 10 by Mike Poole

[Drifter]

9 minutes ago, bluearmy said:

Icon 06z run is a small step away from more amplification with a smaller Arctic ridge and some phasing to our nw looking more likely as the greeny ridge closes up compared to the 00z run 

just one run though 

perhaps I should go back to bed ! 

on a brighter note, the chances of a surprise rise in heights as week 2 progresses like the pub run last night have increased imo 

Glad it’s not just me who isn’t liking the runs this morning, I thought I had taken misery pills. 

[northwestsnow]

I'm just going to go with the flow .

Sounds like big uncertainty has increased reading some of the more experienced guys.

We just got to hope I guess...

[IDO]

I think it is difficult to be positive about the 0z runs. For example the EC for 19th, yesterday 0z -v- today's:

We see the EC moving towards the GFS rather than vice versa. It is no surprise, as GFS had already bought GEM and UKMO before the 0z runs with that surface high interloper.

The only good thing is chaos exists post D6-7. So there may be something interesting, though the NH profile means we need to get lucky for that (IMBY).

[winterof79]

I would say Iberian heights suppressed on 06z compared to 0z on Icon

[TEITS]

Going to disagree with some of the posts today especially with regards to the initial N,ly and how far S this spreads.

If you remember for my location there was a lot of scatter with regards to the N,ly around 16th Jan. Now we have a solid cluster around -8C which for my location isn't bad for a N,ly. Also take note how even 11 days away the mean is still at -4C.

ECM ensembles for my location is also at -4C upto 20th Jan. This might not sound very cold but could be cold enough for snowfall, should fronts move in from the S.

 

Next take a look at ECM for N France. The mean suggests the operational was too far N.

So in summary. We begin with a N,ly, followed by a potential snow event next week (No idea where). Possibly turning less cold for the S before turning back colder again from the N into the following weekend with further snowfall opportunities. Into the following week i.e 21st Jan onwards the potential for an E,ly as I mentioned a few days ago. If this doesn't occur then still likely to remain on the cold side with further snowfall especially for the N as the pattern of blocking and a jet stream further S than normal looks the most likely outcome.

Just remember even during the classic winters of 63 (even though I wasn't born) at times the blocking did relent and briefly the upper temps increased but surface temps remained cold. 

[bluearmy]

3 minutes ago, TSNWK said:

however the 0 850 is at least 100 miles further south over Central France on 00Z it was northern france.

 

2 minutes ago, winterof79 said:

I would say Iberian heights suppressed on 06z compared to 0z on Icon

Yes - I should have noted that in the short term the trough had edged closer and further south. But if the run had continued then the consequences looked to be on the downside rather than the up.  Of course we can only extrapolate and not be certain 

[Crackerjack]

35 minutes ago, That ECM said:

Ridge gate done, bulge gate nearly done. 
 

we now move on to northerly gate and low gate and then longevity gate.

Then the final hurdle ‘Will I be able to get out of my Gate’ 

mum much more positive today guys thanks to all you posters it makes my day. 

[Ice Day]

I think I fall into the @northwestsnow camp this morning of feeling very optimistic.  I do understand that we've lost a strong signal beyond days 5-6, but the ECM, GFS and GEM all show some type of snow event around the county.

For example, this from the ECM at day 8.  Good 'potential' for much of the country

 

Day 9 on the GEM

 

GFS at day 9

 

I like the direction of travel, and it very much fits in with the met office updates.  There's no doubt these types of synoptic bring a 'knife-edge' element to proceedings, but for a bit of model drama, I'd take that all day long.  I'm pretty confident that somewhere is going to hit the jackpot next week, unfortunately for me I think it will be north of my location. West/East Midlands north, up to the Scottish Borders looks in the sweet spot at the moment.  Best model watching in years if nothing else.

 

[SussexSnow]

8 minutes ago, kold weather said:

It's a total mess on the ensembles even on the macro level to be honest, complicated by the fact that relatively minor adjustments will make the difference between a 2 week exceptional spell and a rain event with a little snow for Scotland and SW airflow further beyond.

I think we can only hope it falls favourably for is, it's been a little while since we've really lucked in.

Yes. As an example. At day 4 we have a 10c spread at the 850hpa temp level, and over 15c difference a week out.  So, all to play for really! 

This is for Sussex, as we're at the southern extreme in terms of possible outcomes. 

Edited January 10 by SussexSnow

[Mcconnor8]

Just now, Ice Day said:

I think I fall into the @northwestsnow camp this morning of feeling very optimistic.  I do understand that we've lost a strong signal beyond days 5-6, but the ECM, GFS and GEM all show some type of snow event around the county.

For example, this from the ECM at day 8.  Good 'potential' for much of the country

 

Day 9 on the GEM

 

GFS at day 9

 

I like the direction of travel, and it very much fits in with the met office updates.  There's no doubt these types of synoptic bring a 'knife-edge' element to proceedings, but for a bit of model drama, I'd take that all day long.  I'm pretty confident that somewhere is going to hit the jackpot next week, unfortunately for me I think it will be north of my location. West/East Midlands north, up to the Scottish Borders looks in the sweet spot at the moment.  Best model watching in years if nothing else.

 

Agree with this, for sure we are going to see a lot of IMBY up and down swings in happiness to most of the output coming up when it relates to the snow/rain boundary, but I have low expectations anyway being on the South coast and it makes for interesting viewing for sure compared to the usual dross we get in January especially in recent years.

[bluearmy]

1 minute ago, TEITS said:

Going to disagree with some of the posts today especially with regards to the initial N,ly and how far S this spreads.

If you remember for my location there was a lot of scatter with regards to the N,ly around 16th Jan. Now we have a solid cluster around -8C which for my location isn't bad for a N,ly. Also take note how even 11 days away the mean is still at -4C.

ECM ensembles for my location is also at -4C upto 20th Jan. This might not sound very cold but could be cold enough for snowfall, should fronts move in from the S.

 

Next take a look at ECM for N France. The mean suggests the operational was too far N.

So in summary. We begin with a N,ly, followed by a potential snow event next week (No idea where). Possibly turning less cold for the S before turning back colder again from the N into the following weekend with further snowfall opportunities. Into the following week i.e 21st Jan onwards the potential for an E,ly as I mentioned a few days ago. If this doesn't occur then still likely to remain on the cold side with further snowfall especially for the N as the pattern of blocking and a jet stream further S than normal looks the most likely outcome.

Just remember even during the classic winters of 63 (even though I wasn't born) at times the blocking did relent and briefly the upper temps increased but surface temps remained cold. 

I wouldn’t disagree with you dave - that’s a reasoned well made post 

I’m just concerned about the way the pattern (not just micro)  is changing, almost day to day on the models. 

that doesn’t provide much of a basis for any confidence 

[winterof79]

GFS 06z also getting Northetly in quicker largely due to Less iberian influence

[Midlands Ice Age]

45 minutes ago, That ECM said:

Ridge gate done, bulge gate nearly done. 
 

we now move on to northerly gate and low gate and then longevity gate.

Good post ECM ...

Was producing a post on the old thread but it got locked out. I am using your view of the NH to further my post of last night.

Since my post last night, the GFS has 'railed' in the Pacific high somewhat, but it has also aligned it more east west than it was yesterday.

This has allowed some of the cold Arctic air to slide further south (southern jet increased) over there, and not directly over the pole. This has  enabled the jet to move a bit further south into the Atlantic and produced more 'randomness'  in the Atlantic sector......

Meanwhile the ECM and MO have both picked up the signal for the Pacific high, but it is still a very weak affair and it is aligned similarly to the GFS. 

This has then consequently caused the pull  back  somewhat (so far) of the high retrogression in the Atlantic.

There is a little further to go before we reach the middle ground position, for all the models I suspect. .

Also it does show that the Pacific high is unlikely to be a permanent feature as it wanes pretty quickly.

It, however,  has not significantly affected  the forecast temperatures over our side  (more generally)  -  yet.

As usual, as I suggested last night could happen, we are ending up in a half way house 'blended'  solution which is not without interest for going forward into February, as it enables the possibility of a permanent Scandy to develop over the snowfields there.......  

It also shows that the signal yesterday on the GFS was real, though as usual,  it overestimated the position and strength.

All very interesting from a learning of the models point of view. But what has cause the sudden appearance of the Pacific high? 

MIA

Edited January 10 by Midlands Ice Age

[Mcconnor8]

Just now, winterof79 said:

GFS 06z also getting Northetly in quicker largely due to Less iberian influence

Yeah looks like a nicer run with more amplification early on as well.

[northwestsnow]

1 minute ago, bluearmy said:

I wouldn’t disagree with you dave - that’s a reasoned well made post 

I’m just concerned about the way the pattern (not just micro)  is changing, almost day to day on the models. 

that doesn’t provide much of a basis for any confidence 

It's been a long old chase fir sure !!

[Continental Climate]

It's all become a bit more messy this morning. I'm one of those posters with a glass half empty thus far. Our heights to the north west seem to be decreasing now. Hopefully what has happened is the models have met somewhere in the middle and from now until Friday morning we get little incremental improvements to the northerly and heights to the north west. That's what usually happens in this case I think. What a ball ache it it to get cold into the UK eh? 

[Captain Shortwave]

The outlook looks like a real mess for week 2, uncertainty starting from next Monday where the northerly will likely be cut off as a weak area of high pressure builds in briefly.

   
 

Beyond, big high over the Pacific but uncertainty over the Atlantic.

 

Worth noting that the GFS always has some parcel of weak heights close to the UK to allow the cold air to be near or over the UK and later on you can see that the PV is still pretty mangled.

   
 

At the moment the worst case scenario is a quick return to westerlies helped by the low heights being held on our side of the Arctic by that Pacific block, however if any weak heights can survive then clearly there is scope for anything ranging from cold snaps with wintry precipitation to something more substantial if things fall our way.

I can’t help but feel that the initial Greenland high will probably ease away quite swiftly, but that doesn’t guarantee that things will turn wet and windy, if I recall the February 2021 cold spell still happened despite losing the core heights to the north west as surface height persisted and allow an ENE flow for several days.

Edited January 10 by Captain Shortwave

[TillyS]

5 minutes ago, TEITS said:

Just remember even during the classic winters of 63 (even though I wasn't born) at times the blocking did relent and briefly the upper temps increased but surface temps remained cold. 

This is no ’63

Let's see. I’m in the wary camp this morning but then that’s my default as I’ve been let down sooooo many times in this country.

Anyway, on my travels again shortly. Have just booked some time in the Cairngorms next month. That should means some snow  

[LRD]

Got to be said that, synoptically, this is a big win for the GFS op. Even going against its ensembles it sniffed something that might disrupt a clean northerly flow beyond a day or so and it was basically right. However, what it got wrong was that it would turn mild because it still doesn't look like doing that except maybe in places like Tropical Teignmouth and the rest of the SW

That's not to say it will be mild. Just looks like a different type of cold (messier and possibly more dramatic because of that) than what was being shown for a few days last week/weekend when a clean N'ly looked likely to last all next week

I've said it before and I'll say it again - a really interesting watch this. I'm not pinning hopes on any particular outcome - although it'd be nice to see a couple of weeks of proper winter in January - and it's all the more enjoyable because of that. Still think it's going to be a cold, disruptive 2nd half of next week. Which areas will experience the most disruption is the question

[warrenb]

Just now, LRD said:

Got to be said that, synoptically, this is a big win for the GFS op. Even going against its ensembles it sniffed something that might disrupt a clean northerly flow beyond a day or so and it was basically right. However, what it got wrong was that it would turn mild because it still doesn't look like doing that except maybe in places like Tropical Teignmouth and the rest of the SW

That's not to say it will be mild. Just looks like a different type of cold (messier and possibly more dramatic because of that) than what was being shown for a few days last week/weekend when a clean N'ly looked likely to last all next week

I've said it before and I'll say it again - a really interesting watch this. I'm not pinning hopes on any particular outcome - although it'd be nice to see a couple of weeks of proper winter in January - and it's all the more enjoyable because of that. Still think it's going to be a cold, disruptive 2nd half of next week. Which areas will experience the most disruption is the question

It isn't a big win for anything yet, because none if it has happened

[Cymro]

16 minutes ago, TillyS said:

I mean, strictly speaking the CET is above average. Has been well above average for the first third of the month: 

Met Office Hadley Centre Central England Temperature Data Download

WWW.METOFFICE.GOV.UK

 

It has felt really cold these past two days in the south, and in some cases and places has been cold, but empirically speaking not very. And temps are nudging upwards this week. So, no, not ideal ahead of the apparent snow event next week.

We need deep embedded cold. This isn’t that.

 

The CET is incorrect and hasn't been updated since the 2nd of January and as such we can't draw a reliable picture here based on the CET until it's no longer down. It's likely we're back down to average following an extensively mild first few days. 

Temperatures aren't climbing much above 3-5 degrees this week before tumbling again on Saturday. That is still fairly below average for this time of year. 

Regardless my point stands, the chart you posted in relation to upper air temperatures doesn't tell the full story in terms of surface conditions across the UK. 

 

It's fallen below - 10 in Aviemore for 3 nights on the trot, average it is not!