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

[TSNWK]

Any views on the next chase., personally I’m done with chasing Greenland highs since 2010 they just seem to crash and burn as we get closer to the event.. past 48 hours case in point… once the models picked up on the lobes merging it was game over and the collapse has  accelerated. I recall something similar Christmas period 2022 and I was berated when I stated that once the vortex set as it did early January it could be curtains… it was…

so what’s not to say that with vortex now setting up in its all its glory with cold spilling of the esb to fire up the jet we are could be done again bat a toppler every so often…

Time moving on its already _>lighter by 30 mins in the evening and this increase in daylight is accelerating.
 

like a few other I’ll step away now until if we get something decent..as don’t want to be dolly downer poster… 

toodaloo

[Quantock]

7 minutes ago, Gowon said:

The first time I've looked at the models since the 12z and I can't believe how quickly the cold has collapsed.

I'm hoping it's a data issue and they're all wrong 

MetO and GEM both keep with cold and have high pressure over the UK at T168.  MetO has been pretty solid with the development of this cold spell and it’s the first place I look now before I think changes are going to occur.

Edited January 13 by Quantock
Edit

[Kasim Awan]

Looking more likely now that an active trough will push into Northern England on Monday night to produce snow showers on it's front into low level parts of NW England / NW Midlands before an active core with heavier and more persistent precipitation moves into central areas of northern England. On the lead a complete below freezing sounding means locally significant accumulations to lower levels are possible. As the heavier core makes progress there is the potential for a mild sector to raise the snow line to the west of the Pennines in particular, with orographically lead adiabatic low level cooling reducing this risk to the east of the Pennines. There is uncertainty with regards to the extent of this mild sector therefore the extent accumulations to low levels to the west of the Pennines within the trough core is uncertain. A stronger concensus should be reached by tomorrow evening. 

The longevity of the system is also uncertain. On some model output a slow moving front could produce 20cm+ >250m over the central Pennine region. Other output keeps such core significantly weaker which would limit snowfall. Uppers of -3/-4C in the mild sector support snowfall down to 250/350m with potential for lower in evaporative cooling. More certainty on the main core tomorrow evening.

[Gowon]

The NAGEM is the best I could find, so I'm not giving up yet 

[Guest]

 chilly few days coming up...disappointing after all the hype!

Trouble is the flux capacitor weather time lords jumped down everybody's throats if they dared show anything different to what their mystical machine was showing!

[sunnijim]

Just now, Gowon said:

The first time I've looked at the models since the 12z and I can't believe how quickly the cold has collapsed.

I'm hoping it's a data issue and they're all wrong 

To put this into simplistic terms  if I may.

This whole scenario from the modeling of it days past to what we see playing out in the reliable now never looked sustainable to me in terms of what most of us crave.

Let me be clearer on this.

I have never seen displaced areas of high pressure ( that start in the wrong place) such as centered over the UK on this occasion and drifting to our NW  pay dividends in terms of longevity.

I recall a displaced Euro high once move up toward Scandinavia and allow a bitter NE flow to develop for three days with plenty of snow for the SE in the early part of this Century ( 05 or 06 ?) 

Clearly this scenario can deliver on a temporary basis.

The longevity looking back always seems to come from a scenario where the blocking high forms in  the RIGHT PLACE.

So heights building to our NE or NW then extending their influence from the point of conception.( never moving too far)

This holds the key to longevity

[IDO]

5 minutes ago, Quantock said:

MetO and GEM both keep with cold and have high pressure over the UK at T168.  MetO has been pretty solid with the development of this cold spell and it’s the first place I look now before I think changes are going to occur.

The D7 UKMO is zonal, we are just in the mini-ridge part of the zonal pattern, so colder uppers hang on a bit longer than some model runs. But the pattern has sunk by D6-7:

The GEM op looks wrong. The mean is more representative at D7:

[Phil Blake]

The cold hasn't even got here yet and we are worrying about what's happening in 7days time. Nwp could be over reacting to a signal in which case whole ensemble suites could be incorrect and means well smoothed out. If the Atlantic does barrel through then so be it. Pointless getting worked up over it. It's only weather

[DJ Fart]

I said this back in Dec 22, and it's just as valid now, but I think there are two firmly held beliefs that need revisiting now:

1. "Get the cold in" - we've got the cold in, or will have next week. So what? If it's not going to produce snow, I'd rather it was mild. 

2. "Once embedded, cold air is hard to shift" - we've seen repeated cases now where this simply isn't true. 

Of course everyone in here will be disappointed today, other than those waiting to jump on poor old Scott, I suppose, but the chase has been fun, hasn't it? I've been doing this for years now, way before I joined here in 2013, and I can't really put my hand on my heart and say forecasting power has improved since the mid noughties, despite what I assume must be significant investment in the technology. 

Oh well. See you for the next one!

[Hotspur62]

Well as others have said this morning a rather disappointing trend has been set by the models.Yes down here very likely to see no snow here but week just gone has had temps is 2,3,3,3 and 5 for last 5 days and from today till next Friday a continuation of these temps looks well odds on.We also had a flurry of snow here but not settling yet 8 miles down the road Sevenoaks got 5cms!I am obviously disappointed by no snow but I think a large portion on northern uk will see snow/snow showers this weekI will just enjoy frosty sunny days which is the next best thing for me after snow and boy do we need a dry spell after 10 weeks of heavy rain !!

[SLEETY]

11 minutes ago, Kasim Awan said:

Looking more likely now that an active trough will push into Northern England on Monday night to produce snow showers on it's front into low level parts of NW England / NW Midlands before an active core with heavier and more persistent precipitation moves into central areas of northern England. On the lead a complete below freezing sounding means locally significant accumulations to lower levels are possible. As the heavier core makes progress there is the potential for a mild sector to raise the snow line to the west of the Pennines in particular, with orographically lead adiabatic low level cooling reducing this risk to the east of the Pennines. There is uncertainty with regards to the extent of this mild sector therefore the extent accumulations to low levels to the west of the Pennines within the trough core is uncertain. A stronger concensus should be reached by tomorrow evening. 

The longevity of the system is also uncertain. On some model output a slow moving front could produce 20cm+ >250m over the central Pennine region. Other output keeps such core significantly weaker which would limit snowfall. Uppers of -3/-4C in the mild sector support snowfall down to 250/350m with potential for lower in evaporative cooling. More certainty on the main core tomorrow evening.

So some places are going to see snow? You said a couple of days ago it would be "dry as the Sahara" for the majority of the UK 

Make your mind up

[Kasim Awan]

1 minute ago, SLEETY said:

So some places are going to see snow? You said a couple of days ago it would be "dry as the Sahara" for the majority of the UK 

Make your mind up

I was analysing the operational run bring dry not making a prediction posts like this show a lack of understanding. It will be dry for most anyway, just because the North is getting snow doesn't mean the majority wont be dry.

[Purga]

Blimey - barbeques at the ready. But better tie them down in the blowtorch wind.

[Drifter]

13 minutes ago, Phil Blake said:

The cold hasn't even got here yet and we are worrying about what's happening in 7days time. Nwp could be over reacting to a signal in which case whole ensemble suites could be incorrect and means well smoothed out. If the Atlantic does barrel through then so be it. Pointless getting worked up over it. It's only weather

But the runs all start to fall apart at about the 72 hour mark. This isn’t turning around now. 

People just need to use this as a learning exercise - we have a lot to learn. 

[That ECM]

12 minutes ago, SLEETY said:

Writing off the entire winter because the op runs bring in the Atlantic mid january 

 

I'm also quoting this post in a few weeks, not as if the set-up after this week would take much for it to go back to cold again. 

Let’s be fair. Not what he said. He said into February possibly back end. No mention of winter done from him.

[Drifter]

28 minutes ago, Quantock said:

MetO and GEM both keep with cold and have high pressure over the UK at T168.  MetO has been pretty solid with the development of this cold spell and it’s the first place I look now before I think changes are going to occur.

I think that’s a very generous interpretation of the MetO and GEM runs! 

[SLEETY]

5 minutes ago, That ECM said:

Let’s be fair. Not what he said. He said into February possibly back end. No mention of winter done from him.

More or less he said that,don't try and twist it in his favour  let's see but won't be long before the cold comes back, if it even goes away, a week is a long time in the weather world. 

[Gowon]

2 minutes ago, Spah1 said:

Extremely disappointing after such a big chase to have a Greenie High for 3 days. 
Congrats to those who predicted this pattern weeks away. I have to admit I was hoping for a 2/3 week cold spell . 

I was the same at first until the ECM started messing around with collapsing the block over Greenland I then started hoping for at least a good few days of snowfall.

[northwestsnow]

Just now, Gowon said:

I was the same at first until the ECM started messing around with collapsing the block over Greenland I then started hoping for at least a good few days of snowfall.

It's a shame the low isn't progged another 50 miles north that would have put some of our southern members in the game .

I'm not convinced the track of the lows is finalised yet either BTW ..

 

[Mike Poole]

ECM extended clusters this morning do not bode well, T264+:

Choice of zonal, zonal, zonal, zonal or zonal, take your pick!

[That ECM]

1 minute ago, Mike Poole said:

ECM extended clusters this morning do not bode well, T264+:

Choice of zonal, zonal, zonal, zonal or zonal, take your pick!

Dry zonal please.

[The Northern Ramper]

Snow chances a plenty for Scotland, Ireland, Wales and northern England.

What a fantastic week ahead for most.

[sebastiaan1973]

1 minute ago, Mike Poole said:

ECM extended clusters this morning do not bode well, T264+:

Choice of zonal, zonal, zonal, zonal or zonal, take your pick!

The wind plume at De Bilt, gives the same grim picture.  Z= south, NO= noordoost, ZO= zuidoost. 

[northwestsnow]

3 minutes ago, Mike Poole said:

ECM extended clusters this morning do not bode well, T264+:

Choice of zonal, zonal, zonal, zonal or zonal, take your pick!

Cluster 2 please Mike !!

[Drifter]

5 minutes ago, Mike Poole said:

ECM extended clusters this morning do not bode well, T264+:

Choice of zonal, zonal, zonal, zonal or zonal, take your pick!

Can’t help thinking this is once again due to the US having an epic cold spell that fires up the jet more than expected. 

Edited January 13 by Drifter