Model Output Discussion - A cold start to Spring?

[Snowy L]

18 minutes ago, Scott Ingham said:

This isnt the Met lmfao its met4cast who posts on our website hahaha

 No I mean the met office warning states that southern areas have the highest chance of snow and I've posted the wet bulb showing northern areas are closer to the wet bulb freezing level.

[Battleground Snow]

06z ECM trending Thursdays low south 

[sheikhy]

Ecm 06z further south and west and takes snow further south aswell!!good stuff!just noticed @Battleground Snow you just posted same thing!!

[Updated_Weather]

Can see more trends further south occurring as we go further in the week. ECM06z does have the low for Thursday quite a bit more south than 00z

[nick sussex]

The flatter the low generally correlates with an increased chance of snow on the northern flank .

I don’t think we’ve seen the last of the changes though so as to where the snow finally ends up still more runs needed .

[BLAST FROM THE PAST]

51 minutes ago, Catacol said:

I'm not going to be popular....but I think a lot of folk are going to see cold rain for the most part this week - and nothing close to approaching 2018. At elevation a different story but unfortunately for me the setup has gone awry. Blocking to our north is set to transition westwards very quickly and this will allow the atlantic to come in much flatter than we want. There is no block for these systems to bump and slide against, instead a cold trough pushing in from the NE but the cold trough itself isnt making sufficient inroads to get entrenched cold in place as we did at least manage to get in early December.

Why? The origins of a less wintry setup I think lie in the worry I had last week, namely that the remnants of the vortex setup too far east. This was a change to what was modelled initially and it has worked against getting artic air to flood far enough west. You can see it clearly here - setup last night shows the block in place and the deep trough over Scandy

and then wind forward 72h and the trough has essentially gone nowhere - stalled due to lack of momentum inspired from aloft because of the positioning of the SPV

Heights pulling very fast towards Canada, atlantic pushing in a merging with the Scandy trough - and for me this is classic nasty cold rain conditions for the vast majority away from Scotland.

To labour the point a bit - here is the vertical profile of the vortex right now

way - way out east whereas back in the days when the SSW was getting exciting this was where it was projected to be:

Location and angle have changed and absolutely not to our advantage.

Note also how the MJO has panned out: we hit phase 7 in good time.....and it died. It dropped into the COD taking away the signal for northern blocking when we wanted it and is now surging dramatically once again into the West Pacific - but much too late to give support to our current pattern this week.

This suggests a chance for renewed blocking in the second half of the month, but I think in truth by then it is too late for any deep, sustained cold. Spring will be on its way.

Not the right time for an end of season reflection yet - things can and do change and I hope this post is left looking daft in 3 days' time as people wade through the drifts...but for me another opportunity looks set to slip by. I have seen more frost this year than in many years but for swathes of the south I think this winter is going to go down as a "so near and yet so far" kind of season. 

Re the MJO For second half…..that is when imo the main thrust will be and the thrust to be very noteworthy indeed….especially as I don’t think we’ll lose too much of the current cold

ALL to play for imo

BFTP

[MattStoke]

Indeed, a sizeable jump southward between the ECM 0z and 6z.

[Stephen W]

38 minutes ago, Catacol said:

I'm not going to be popular....but I think a lot of folk are going to see cold rain for the most part this week - and nothing close to approaching 2018. At elevation a different story but unfortunately for me the setup has gone awry. Blocking to our north is set to transition westwards very quickly and this will allow the atlantic to come in much flatter than we want. There is no block for these systems to bump and slide against, instead a cold trough pushing in from the NE but the cold trough itself isnt making sufficient inroads to get entrenched cold in place as we did at least manage to get in early December.

Why? The origins of a less wintry setup I think lie in the worry I had last week, namely that the remnants of the vortex setup too far east. This was a change to what was modelled initially and it has worked against getting artic air to flood far enough west. You can see it clearly here - setup last night shows the block in place and the deep trough over Scandy

and then wind forward 72h and the trough has essentially gone nowhere - stalled due to lack of momentum inspired from aloft because of the positioning of the SPV

Heights pulling very fast towards Canada, atlantic pushing in a merging with the Scandy trough - and for me this is classic nasty cold rain conditions for the vast majority away from Scotland.

To labour the point a bit - here is the vertical profile of the vortex right now

way - way out east whereas back in the days when the SSW was getting exciting this was where it was projected to be:

Location and angle have changed and absolutely not to our advantage.

Note also how the MJO has panned out: we hit phase 7 in good time.....and it died. It dropped into the COD taking away the signal for northern blocking when we wanted it and is now surging dramatically once again into the West Pacific - but much too late to give support to our current pattern this week.

This suggests a chance for renewed blocking in the second half of the month, but I think in truth by then it is too late for any deep, sustained cold. Spring will be on its way.

Not the right time for an end of season reflection yet - things can and do change and I hope this post is left looking daft in 3 days' time as people wade through the drifts...but for me another opportunity looks set to slip by. I have seen more frost this year than in many years but for swathes of the south I think this winter is going to go down as a "so near and yet so far" kind of season. 

Excellent post as always and thank you for taking the time to write your thoughts and thinking. I guess the MO think that the risk is still present for disruptive snow this week but I agree completely, the situation is marginal for many unless you are in Scotland, the far north of England or at elevation. In my location, I’m now not expecting anything other than perhaps a snowflake if I’m lucky. The block just hasn’t been able to hold sufficiently to get the deep cold entrenched and so we end up in that messy mix of transient snow if we are lucky as Atlantic fronts try and make inroads (which often don’t make it over to me in north Norfolk).  No doubt a few surprises will crop up and I hope many will get lucky. 

[Updated_Weather]

Just now, MattStoke said:

Indeed, a sizeable jump southward between the ECM 0z and 6z.

Got a feeling maybe we could hold on to the cold in the south. Maybe south coast gets the milder air in before another reload push from the north.

All interesting nonetheless. But yes, a sizeable move south in that position of the low for Thursday!

[Rain All Night]

11 minutes ago, BLAST FROM THE PAST said:

Re the MJO For second half…..that is when imo the main thrust will be and the thrust to be very noteworthy indeed….especially as I don’t think we’ll lose too much of the current cold

ALL to play for imo

BFTP

The ensemble suites have been suggesting that the main TPV will move northwards and that troughing may develop to our east. What do you make of that?

Edited March 6, 2023 by RainAllNight

[BLAST FROM THE PAST]

3 minutes ago, RainAllNight said:

The ensemble suites have been suggesting that the main TPV will move north (but not west) and that troughing will develop to our east. What do you make of that?

Yep, that’s towards my thoughts.  I still stand by that March will be a ‘very noteworthy’ month for depth of cold shots and a ‘lengthy’ cold set up.  I’m skiing in Val D’Isere from 17th….so I’ll watch from afar soon enough.

 

BFTP

Edited March 6, 2023 by BLAST FROM THE PAST

[Ali1977]

EC 06z mean , M4 corridor looks like prime target on Wednesday , up to south midlands and down towards the south coast!!

 

 

Edited March 6, 2023 by Ali1977

[Man With Beard]

1 hour ago, Catacol said:

I'm not going to be popular....but I think a lot of folk are going to see cold rain for the most part this week - and nothing close to approaching 2018. At elevation a different story but unfortunately for me the setup has gone awry. Blocking to our north is set to transition westwards very quickly and this will allow the atlantic to come in much flatter than we want. There is no block for these systems to bump and slide against, instead a cold trough pushing in from the NE but the cold trough itself isnt making sufficient inroads to get entrenched cold in place as we did at least manage to get in early December.

Why? The origins of a less wintry setup I think lie in the worry I had last week, namely that the remnants of the vortex setup too far east. This was a change to what was modelled initially and it has worked against getting artic air to flood far enough west. You can see it clearly here - setup last night shows the block in place and the deep trough over Scandy

and then wind forward 72h and the trough has essentially gone nowhere - stalled due to lack of momentum inspired from aloft because of the positioning of the SPV

Heights pulling very fast towards Canada, atlantic pushing in a merging with the Scandy trough - and for me this is classic nasty cold rain conditions for the vast majority away from Scotland.

To labour the point a bit - here is the vertical profile of the vortex right now

way - way out east whereas back in the days when the SSW was getting exciting this was where it was projected to be:

Location and angle have changed and absolutely not to our advantage.

Note also how the MJO has panned out: we hit phase 7 in good time.....and it died. It dropped into the COD taking away the signal for northern blocking when we wanted it and is now surging dramatically once again into the West Pacific - but much too late to give support to our current pattern this week.

This suggests a chance for renewed blocking in the second half of the month, but I think in truth by then it is too late for any deep, sustained cold. Spring will be on its way.

Not the right time for an end of season reflection yet - things can and do change and I hope this post is left looking daft in 3 days' time as people wade through the drifts...but for me another opportunity looks set to slip by. I have seen more frost this year than in many years but for swathes of the south I think this winter is going to go down as a "so near and yet so far" kind of season. 

Wow that's an interesting call ... I suspect you could be right in the extreme south where cold won't be as strong, and perhaps close to the E coast, but I think for northern England inland snow is a safe bet myself, unless models change. I note the Met Office have their Thursday/Friday warning for this area on a trajectory that could reach a red warning, and I can't say I blame them looking at the models. I just don't think so many weather models are going to get the fine details wrong. I recall two years ago there was an easterly in January that the ECM kept forecasting as rain - I couldn't believe it, rain on an easterly in January?? yet of course the ECM was right. On the other hand, the ECM is currently going for a period of snow all across Northern England on Thursday (possibly turning back to rain later), the exact location of the snow tbc but wherever it is, the ECM looks rock solid it will be snow.

Still, I will follow with interest and remember your words if it's a big fail!

[Lampostwatcher]

3 minutes ago, Ali1977 said:

EC 06z mean , M4 corridor looks like prime target on Wednesday , up to south midlands and down towards the south coast!!

 

 

The metoffice have warning south of the m4

[Ali1977]

2 minutes ago, Lampostwatcher said:

The metoffice have warning south of the m4

The latest mean ties in with the UKV , so maybe they’ll widen it. 

 

The GEFS mean similar 

Edited March 6, 2023 by Ali1977

[tight isobar]

An easier clasp of evolutions- ssts are Mass factor at most times, yet into the meteorological spring- they can/ will be beneficial with such dynamics!.. however it’s not rocket science- nor meteo- depth, to paw thought on the maritime influence west- to east. Where the Atlantic bounding formats inevitably syphon stagnant TM air, while the North Sea verses the roll of polar continental stamp!-  And the point in basic, is that both aids, n, reverts a global minuscule island/ and it’s mass differences in overhead fruition!!!       In this occasion- it’s a worthy punt MOST will see dendirte- ( snow) in some appliance!!! .. yet now without doubt, some will see memorable snowfall!!! - lastly once again a milder interlude looks game, but I can’t see it overriding a mid latitude in dripping!!!!

Edited March 6, 2023 by tight isobar

[sheikhy]

Ecm control goes further south for friday aswell!!

[Nick2373]

06z i think shows a fine line between cold rain and snow costal areas South, obviously the further you go in terms of elevation the higher chance of snow . This pattern in all fairness as been showing since last week where we see a milder push around the 11th Catacol pointed out earlier that most will see rain South wise, unless something miraculous happens in the next 24hrs i would tend to agree.  If its snow you desire head hill wards

[dryfie]

Upper air soundings updated for midday.  Fall in Faroes temps seem to be levelling off.  

 

Thicknesses.doc
 

Thicknesses.doc

Edited March 6, 2023 by dryfie

[kold weather]

9 minutes ago, Snowy L said:

Not going to lie I don't know if it's the graphics but that looks awful. The tiniest patches of snow in the mostly rain bands on Tuesday and Wednesday then a low on Thursday showing zero sign of trough disruption. If Met Office models have it right then in the screenshot even Northern Scotland would struggle to get snow. Seriously hope that's wrong.

 

Luckily the UKMO was an absolute rank outlier on the models, and having looked at just about all ensembles I can think of (ECM,GFS,CMC,ARPEGE) and I think I've seen maybe 10-15 out of a cumulative 200 odd that look even remotely close to that, and the UKMO is probably maybe no.2-3 in terms of utter worst cases.

Anyways long ways to go yet still. 

As for Wednesday warning from METO, I undersand why they have only gone that far, there is still way too much uncertainty in the models on the northern extent, and indeed the entire evolution which is complex it has to be said.

[MATTWOLVES 3]

Hey guys regardless of where the models are taking the weeks snow...keep in mind there's gonna be a variation from run to run. Also keep in mind the met have issued 21 pages of warnings on the BBC...And there's one for significant disruptive snow for Thursday and Friday which was only updated at 12pm!

There's a lot going on and there's a chance of major disruption for various places. 

I hope those who see the snow get the chance to enjoy it,but be aware fatalities and injuries will occur...so be please be smart throughout this upcoming period.

Spring may be here..but its sprung right back into Winter.

Have fun

Oh and thanks for the wonderful and insightful updates.. im struggling for time the next few days to post or follow the models..so keep em coming...cheers gang.

 

Edited March 6, 2023 by MATTWOLVES 3

[Stuie]

The Icon 12z of tomorrow mornings precipitation in the South.

EDIT: Arpege

Edited March 6, 2023 by Stuie

[Updated_Weather]

6 minutes ago, Stuie said:

The Icon 12z of tomorrow mornings precipitation in the South.

Good to see some heavier precipitation. Could mean more heavy snow;)

[Cambrian]

The 6z GFS ensemble mean run to day 8 further limits any mild incursion to the southern half of the UK and Ireland and to a window between day 4 and day 7. The mild air makes very little inroads into the northern half where comfortably sub-zero T850s persist throughout. Just as an aside, look at that surge of cold from Siberia to Iceland and Greenland.

Whether we consider it as a proper cold block or not, it’s cold air and the Atlantic lows are clearly disrupting against it. 

The full extent of the disruption of the Atlantic trough by the cold air is shown nicely at 60h, followed by the breakaway low getting into the southern UK and Ireland by 84h, the Atlantic low still being squeezed but encroaching north to our west at 108h, trying to drag milder air up over us at its furthest eastern reach.

  

The point is we never get exactly what the mean indicates, even at day 4, less so at times like this. The spreads are telling : 5+ dam range across the southern UK, and 4-5 degrees range on the T850s across most of Ireland and the southern UK.

 
 

It’s these zones that the models are adjusting southwards into, 6z ECM the latest. 

One of the variables that must be difficult to gauge is just how much that surge of cold air from Siberia to Iceland and Greenland and into the Atlantic will impact on the Atlantic trough as it rushes to mix in with the air circulating around its northern flank, the very same flow coming all the way around to our south. Working out the mixing and final uppers on this one must be a nightmare!

Quite possible that the big guys with the supercomputers and enormous experience will get it about right, but I don’t envy them having to make a call on this episode even with only 4 days to go!

[The Enforcer]

4 hours ago, nick sussex said:

You can see the wave and how it ripples eastwards here .

So the wave develops towards Bristol on the T24hrs chart .

 

In the T36hrs chart you can see the wave towards the Low Countries .

The wave slows the front and also helps to intensify the precip .

You also have a slack flow north of the front with little mixing so evaporative cooling comes into play.

In 12 hrs the front has only edged about 50 miles south.

 

Any similarities with this situation?

"What about snow from that cold front?"

"It's a decaying feature."

Red warning - every dog has its day.