Model Output Discussion. 3/12/2022. How cold will it get?

[Kasim Awan]

Just now, LRD said:

Indeed. Pretty slim pickings, chasing around after a dusting with the pattern we're about to enter in to. I don't know why this spell will be so dry. It screams instability but there's next to nothing unless you live on the East Coast or on the Northern half of Scotland

Its not particulatly unstable though my friend - its a slack weakening low so there lacks a tendency for trough development & inlandward shower progression. Not a classic northerly by any means.

Yes it will be a case of chasing dustings. Laughable really with a 1050mb Greenland block and -10 upper air. There's just about enough in it for 2-3cm very locally in one or two troughs / streamers. 

[Rain All Night]

4 minutes ago, LRD said:

Indeed. Pretty slim pickings, chasing around after a dusting with the pattern we're about to enter in to. I don't know why this spell will be so dry. It screams instability but there's next to nothing unless you live on the East Coast or on the Northern half of Scotland

Is there just not much moisture in this incoming air to begin with?

[CanadaAl]

4 minutes ago, Met4Cast said:

No denying todays trends aren't favourable but I'll wait until the overnight runs to comment - Still some members going for prolonging the cold & I suspect there will be a few more shifts in outputs to come as the low is yet to be fully resolved. 

Frustrating for sure, but not entirely over yet.

Depends really, the GFS is looking encouraging with the Euro/Scandi heights building towards the end. Yes it's FI and will change but this is not the first run to suggest this outcome. 

[John88B]

9 minutes ago, MATTWOLVES said:

Is it time to worry when the CFS gets rolled out?

Firstly there's some signs of snow potential for sure followed by a Battleground scenario before turning milder. 

But guess what! The heights regain traction around the NW by Xmas and we again end up with a colder spell...perhaps much colder.

All for fun but it may not be a million miles from the truth! a few hundred but not a million

And guess what the Vortex is split and basically saying that's me done for the winter...I've never been able to get going this time around...sub me I've had enough!

Got to keep ya spirits up folks...things still look pretty solid. And its nearly xmas...

And I should imagine as we get deeper into winter those cold shots would get much colder.

Edited December 6, 2022 by John88B

[LRD]

Just now, RainAllNight said:

Is there just not much moisture in this incoming air to begin with?

Dunno to be honest. Beyond my expertise. But I guess you're right. It's just all very underwhelming for the next few days. Next week could still be significant, though of course, even though things have turned against that for now

[SnowBear]

Not sure if any model is going to be worth much at the moment, not until we get some clearer idea of what that potential hurricane is going to do. Any that does come out to be good will be more luck than anything. 

Those who have seen the 5 day Graphical output on the NHC website will note the huge possible forward track, a small shift of a spinning top like system today could mean hundreds of miles difference at day 5.

There is also a 50% chance of it forming a tropical system... Or 50% chance of it not and maybe just fading away. 

The models will struggle at the moment due to the large possibilities of that system. 

Patience is now needed, watch and wait... Something so common with hurricanes. 

 

[stodge]

2 minutes ago, RainAllNight said:

Is there just not much moisture in this incoming air to begin with?

I think that's true though I did wonder if convection might occur as it passed over the warmer North Sea.

[Kasim Awan]

3 minutes ago, RainAllNight said:

Is there just not much moisture in this incoming air to begin with?

The convection / moisture is supplied by temperature contrast and wind speed. Tempetature contrast is the same as 1 Dec 2010. It's the second factor (wind speed) that is missing.

[Methuselah]

1 minute ago, RainAllNight said:

Is there just not much moisture in this incoming air to begin with?

Well, over land at least, there's nothing to instigate convection: the air mass may be intrinsically 'unstable' but there's next to no insolation. That's why windward coasts get all the action. Disturbances are of course another matter.

[CoventryWeather]

Models have appeared to have solved that area of snowfall for Thursday, tending to push across Northern Ireland and into Western Wales. Most look likely to stay dry. Hopefully there is a shift back east tomorrow, but holding little hope for anything substantial.

[Kasim Awan]

Just now, Ed Stone said:

Well, over land at least, there's nothing to instigate convection: the air mass may be intrinsically 'unstable' but there's next to no insolation. That's why windward coasts get all the action. Disturbances are of course another matter.

its wind speeds that are responsible for pushing showers inland *and* strengthening precip associated with troughs. that is missing. the low is also in a weakening state reducing momentum available for trough development.

i think, bar a lucky few, those expecting half decent snow from this northerly will be extremely dissapointed

1 minute ago, CoventryWeather said:

Models have appeared to have solved that area of snowfall for Thursday, tending to push across Northern Ireland and into Western Wales. Most look likely to stay dry. Hopefully there is a shift back east tomorrow, but holding little hope for anything substantial.

Imo not quite yet, ukv and icon still holding onto the more central track, nowcast

Tomorrow night we will know as we see where it is on radar compared to output

[pureasthedriven]

Tell you what, regardless of all these inter-run shenanigans, give me an Azores low over an Azores high any day. 

[BLAST FROM THE PAST]

14 minutes ago, london-snow said:

All due respect members are used to quotes ‘two or three bites of the cherry’ and ‘the worm is turning’  never turns out that way does it..

I still for one feel that tomorrow is landing zone and that the picture should be painted clearer going forward. 
 

For the sake most on here i do hope.

It’s about not worrying about 1 op run. Why is this ECM 12z suddenly so accurate? 
BFTP

[bigdog1]

In the last 10 days how many flips one way with the models and then flip back the other way this will happen right through the winter this will change again by morning I think the only real way to study our British weather is now casting 

Edited December 6, 2022 by bigdog1

[MattStoke]

2 minutes ago, Kasim Awan said:

its wind speeds that are responsible for pushing showers inland *and* strengthening precip associated with troughs. that is missing. the low is also in a weakening state reducing momentum available for trough development.

i think, bar a lucky few, those expecting half decent snow from this northerly will be extremely dissapointed

Imo not quite yet, ukv and icon still holding onto the more central track, nowcast

Tomorrow night we will know as we see where it is on radar compared to output

ICON and UKV now take it through Wales too. Giving up on this one. Looks like a dry cold spell here bar any potential frontal snow next week.

[Liam Burge]

The NOAA outlook for the to-be or not-to-be tropical storm suggests that it will only have essential 1 or 2 days to strengthen before it hits cooler waters and begins to weaken.
Quote: "By Thursday night or Friday, the low will move northeastward over cooler waters and interact with a mid-latitude trough, limiting subtropical or tropical development of the system."

What is also interesting to note is that they say "subtropical or tropical storm could form in the next couple of days." which would really only give this system about a day or so of strengthening. This means that the models are most likely overdoing how strong this low will be and we can expect downgrades in the intensity of the low in the coming model runs.

 

EDIT: On the GFS run you can see that the low is still rapidly strengthening all the way out to Sunday before it begins to weaken. However, it will be over cooler waters by Friday.

Edited December 6, 2022 by Liam Burge

[I remember Atlantic 252]

2 minutes ago, MattStoke said:

ICON and UKV now take it through Wales too. Giving up on this one. Looks like a dry cold spell here bar any potential frontal snow next week.

dosen't even look like a NW'ly drift, everything points to our area seeing no snow before the possible frontal boundary

[SqueakheartLW]

Just a bit of interest from a colder perspective on the latest ECM, GFS and GEM runs, that is the ones I can show since the ensemble chart for today's GEM 12z hasn't appeared on wetterzentrale for some unknown reason and ECM 12z isn't up to date yet.

I have focused on what the potential could be if the milder runs later on don't come to pass and we stay cold based on 850hpa temps anyway.

Below I have the latest 4 GFS runs showing with the ensemble mean but the added thing is that I have removed any member that gets 850hpa temps above 0C at any stage just to show what could and probably will end up happening due to the nature of the setup.

850hpa temps predictions

GFS 18z, 00z, 06z and 12z

GEM 00z and ECM 12z

What the above is showing that despite the ensemble mean moving back up towards something less cold or even milder there are still a fair number of ensemble members keeping the 850hpa temps below 0C throughout their runs.

 

Did anyone notice this on the GFS 12z 2m temperature charts from meteociel today

GFS Op run is predicting a 2m temp of -273.1C in Scunthorpe at midnight on 14/12/22

I'm not joking, it really does say -273.1C

Maybe the day after tomorrow is finally happening and the cold vortex that freezes things instantly is going to touch down in Scunthorpe

[Kasim Awan]

1 minute ago, MattStoke said:

ICON and UKV now take it through Wales too. Giving up on this one. Looks like a dry cold spell here bar any potential frontal snow next week.

Its the azores high that has destroyed that trough

its only in wales because it lacks the intensity to push east . even there - 1-4mm id say. chances on this correcting east again are slim.

i wouldnt even describe this as a faux northerly - more of a canvas of a northerly that never got painted on.

[MattStoke]

Just now, I remember Atlantic 252 said:

dosen't even look like a NW'ly drift, everything points to our area seeing no snow before the possible frontal boundary

More significant cold spells rarely deliver here. It’s the marginal events that bring rain for most that deliver here, rather ironically.

[That ECM]

If there is to be a battleground situation that is 5-6 days away then you would expect output to show it going wrong and go right by the very nature it’s a battleground situation. 
 

now people can be forgiven that past experience of letdowns affecting emotions but it doesn’t always pan out as before. We will have to wait and see because no one knows.

 

I’ve always loved the saying that people who tell you they can predict the future are liars even if on occasions they are proved correct.  JH has said many times the weather will make you look a fool at times. 

[seaside boy]

Sector Images: Northern Atlantic - NOAA / NESDIS / STAR

WWW.STAR.NESDIS.NOAA.GOV

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Near real-time publication of GOES-East and GOES-West images from NOAA/NESDIS/STAR

here are some North Atlantic charts showing  the position of the  current disturbance.

What's your comments on this  ??

[weatherguy]

Well, that ECM certainly caught me off guard!  No getting around the fact that it's poor in the medium-term and a hell of a downgrade.  

However, no need to throw the toys out of the pram over one run.  Especially when the GFS/UKMO/GEM are all still on board, to varying extents, for a lot of snow potential as LP systems track to the south of the UK.  I do understand there will be a certain amount of IMBYisms for such a setup, mind.

Just for fun though, a look at that ECM +240h chart:

The tPV is still under severe pressure and, were this to come off exactly (barely a chance in hell, in my opinion) at T0, I'm sure there'd be another spell to be chasing in the not too distant future. 

[pureasthedriven]

1 minute ago, That ECM said:

If there is to be a battleground situation that is 5-6 days away then you would expect output to show it going wrong and go right by the very nature it’s a battleground situation. 
 

now people can be forgiven that past experience of letdowns affecting emotions but it doesn’t always pan out as before. We will have to wait and see because no one knows.

 

I’ve always loved the saying that people who tell you they can predict the future are liars even if on occasions they are proved correct.  JH has said many times the weather will make you look a fool at times. 

And a stopped clock is right twice a day, etc. Too true. 

[I remember Atlantic 252]

2 minutes ago, MattStoke said:

More significant cold spells rarely deliver here. It’s the marginal events that bring rain for most that deliver here, rather ironically.

Aye, like storm Arwen