Model Output Discussion - A cold start to Spring?

[Lukesluckybunch]

9 minutes ago, NewEra21 said:

This has been my point for days now, despite the odd op run we're just not seeing the depth of cold to make anything worthwhile.

We've had -8 uppers in the SE this weekend just gone, which resulted in 8c.

I'd love for this potential cold spell to happen, but personally I'm just not seeing the depth of cold that we'll need in March.

A few slushy deposits at best from current output.

Day time temps currently are nothing to be happy about..overnights maybe close to freezing or just below..I'm glad someone is seeing what I am

[LRD]

15 minutes ago, NewEra21 said:

This has been my point for days now, despite the odd op run we're just not seeing the depth of cold to make anything worthwhile.

We've had -8 uppers in the SE this weekend just gone, which resulted in 8c.

I'd love for this potential cold spell to happen, but personally I'm just not seeing the depth of cold that we'll need in March.

A few slushy deposits at best from current output.

Yes I agree. The -10 line needs to be breached, at least initially, in the south I reckon. But, there is a caveat in that the 850s aren't everything. Don't now the exact science but there are other factors that could drop temps to nearer 3 or 4C and change rain to snow even if it doesn't hang around for long

I totally get your point though

Edited February 27, 2023 by LRD

[LRD]

7 minutes ago, Ali1977 said:

The control at 192 is quite similar to the ECM at 192, but also colder. Maybe this is where we are heading, and then hope the block holds as the SSW does it’s thing creating lots of slider style snow events !! 

A long way off but potential a very snowy period next week. 

I thought there was a swear filter on here 

[Guest]

Ensembles rolling out, control and det. GFS both towards the bottom of the pack around the start of the crucial time frame.

 

 

[seabreeze86]

3 minutes ago, Lukesluckybunch said:

Day time temps currently are nothing to be happy about..overnights maybe close to freezing or just below..I'm glad someone is seeing what I am

Uppers are not everything I’ve seen drizzle at -10 and snow at -2. There are far more parameters at play. There was a brilliant post from snow king last year that illustrates this far better than I can 

Air temperature will change in minutes if showers come along. 

[Ali1977]

Plenty of good ENS at T204 holding the block  - I feel we have many upgrades to come over the next 24 hours personally. 

[LRD]

Yes GFS 6z op and ctrl follow each other 850s-wise. I don't know if that really means anything in the grand scheme of things, though

[EML Network]

6 minutes ago, MATT TATTOO said:

There is nobody ganging up on a particular member mate. If your following a particular poster and one post they are saying things look good,then the next post they're saying things look bad,I'm sure you can understand how some would get very confused!

I happen to find Lukes analysis very refreshing..he does jump the gun a little but he offers some good insight,and tbh he reminds me of a certain Shaky character. So if he is being picked on I most certainly disagree with it.

All good in the hood, it's just others jumping on the bandwagon that frustrates me. 

Think weve all been guilty of doing it though at some point or another. And its kinda understandable given the model instabity' especially GFS since its much fabled down/up - grade

Anyhows..onwards and upwards

[sebastiaan1973]

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020RG000708

Right now we are experiencing the second SSW. [negative value 60N, 10 hPa.] 

Consider 27th of february as the start date. When we take a look in the literature, we see this picture by Baldwin. The composite of weak vortex events. 

In 10-12 days after the start date [27th of february], we see less downwelling. Perhaps we see this too in the EC NAO forecast. First we have a negative NAO, around 11 of march it will become positive. When we fellow the picture of Baldwin, this will period will be short. After negative NAO, round the end of march again positive NAO, turning negative in april.  

Perhaps this is a guideline for things to come.

Edited February 27, 2023 by sebastiaan1973

[mushymanrob]

I wont claim to be all knowlageable about these charts, but from what i can gather, the gist of it suggests that theres no (or little) SSW impact here for us within this timeframe, that out to the 15th, in fact, these charts appear to lessen the chances.
 

Edited February 27, 2023 by mushymanrob

[Chesil View]

In the reliable/semi reliable  timeframe across most models we have broad agreement on retrogression to Greenland.

Long enough and strong enough to bring some very cold air south across the UK.

We just about get to the point where the low approaches from the west.  Beyond that I'm not sure the models really know what to do with the low some bring it in after a bit of a battle ground others are more slidey.

Are they overestimating /underestimating the strength of the block and the same with the westerly/southwesterly push. 

We shall see. Beyond the retrogression I don't see anything as settled or nailed on as yet.

Fine margins either way though.

 

[Blizzardof82]

I am a novice when it comes to reading charts but could I be right in thinking  this latest warming could be what scuppers our chances of a decent cold spell, as everything was going nicely up until latest reversal?

[nick sussex]

3 minutes ago, mushymanrob said:

I wont claim to be all knowlageable about these charts, but from what i can gather, the gist of it suggests that theres no (or little) SSW impact here for us within this timeframe, that out to the 15th, in fact, these charts appear to lessen the chances.
 

The top right chart shows some downwelling into the trop, and then some resurgence in the zonal flow towards the end . 

The NASA charts are better as they show the latitude and these show quite a strong reversal into the trop extending from the pole down to wards around 45N .

 

[Mike Poole]

3 minutes ago, Blizzardof82 said:

I am a novice when it comes to reading charts but could I be right in thinking  this latest warming could be what scuppers our chances of a decent cold spell, as everything was going nicely up until latest reversal?

I think the last day or so’s modelling shows that as the models have got to grips with the latest warming / wind reversal in the strat, the signal for a ridge into Greenland on the timescale of a week has massively increased from a point where it was looking rather doubtful, so quite the contrary at least initially.  What happens after that seems rather unclear still…

[Matt Jones]

After looking at this mornings runs nothing yet to get over excited about, really not keen on the battleground scenario so often it's a bust then you have nothing to fall back on, convective NE'ly or straight Northerly is what I want to see. ECM in it's latter stages may look impressive but it only takes a shift north and your left with nothing, can still see potential but currently I'm 65% bust on this and 90% bust for my location.

[Nick2373]

06Z delivers pretty much a trending situation in terms of something colder for 2 days, then hints of more South Westley direction thereafter. From reading other posts its showing in the teleconnections as well, Goes to show that SSW Don't always deliver what's wished for    

[Kieran1960]

Plus alongside the milder trends being shown met office is going for a drier and warmer spring likely hood 

[KTtom]

18 minutes ago, Nick2373 said:

06Z delivers pretty much a trending situation in terms of something colder for 2 days, then hints of more South Westley direction thereafter. From reading other posts its showing in the teleconnections as well, Goes to show that SSW Don't always deliver what's wished for    

It does look, well to me anyhow, that we are looking at a 2 day spell of cold uppers (cold enough for snow) followed by the Atlantic pushing in. Maybe some brief snowfall but nothing really pointing to a long cold spell that I can see. 

[tesaro]

To be honest, I see plenty of potential towards the back end of next Week. We needs the Trough to drop sufficiently South before the Atlantic Front rolls in. It’s not the end if it drops a little to the East. A disrupting Low tugging in low Dewpoints from the Continent is often a Jackpot recipe if you are partial to a good dump of Snow. Would rather have that than a Cold Northerly with just Coastal Shower Wishbone stuff

[seabreeze86]

Still a big spread on the MOGREPS 6z but there as now members going below -10 which wasn’t the case on the 0z

All to play for 

For Newcastle 

[Rain All Night]

1 hour ago, Mike Poole said:

I think the last day or so’s modelling shows that as the models have got to grips with the latest warming / wind reversal in the strat, the signal for a ridge into Greenland on the timescale of a week has massively increased from a point where it was looking rather doubtful, so quite the contrary at least initially.  What happens after that seems rather unclear still…

The ensemble suites seem to have made clear that they think we're going southwesterly after a brief possible northerly. I will keep an open mind, and will be interested to see if the ensembles can be flipped by the second SSW.

Just for fun, here are the latest CFS anomaly charts, seeming to show the Azores high taking another round of steroids in week 4.

[Daniel*]

According to literature for there to be a distinct new major SSW at least 30 days need to pass with zonal wind in westerly this will not be met, therefore the SSW seen in mid February and further easterly reversals are all part of the same SSW event.

 

[feb1991blizzard]

5 minutes ago, Daniel* said:

According to literature for there to be a distinct new major SSW at least 30 days need to pass with zonal wind in westerly this will not be met, therefore the SSW seen in mid February and further easterly reversals are all part of the same SSW event.

 

yes - read this some time ago - thought it was less than 30 but stand corrected.

[minus10]

Well with the second ( or is it the third...lost count) reversal going on i'm.not sure whether what is being shown now by the models wont change again as the effects of the downwelling continue to be felt, however there is now a definate trend to return to westerly zonal with the vortex still very much 'alive' and back or heading back to its natural home by mid March..none the worst for its ordeal...

...this is clearly seen in the means and ens with many turning milder in later stages of runs...

...seems that in the shorter term yes something colder...will be interesting to see though whether this westerly signal continues and even intensifies..still find it strange though given the time of year and the battering the vortex is having by these reversals that it can still recover seemingly in a fairly robust way...as ever time will tell..

 

[Chesil View]

The imprint of the second reversal suggests  I believe a reversal down to about 45 degrees  north latitude which is south of the UK so I"d be taking any progressive westerly regimes shown with a decent sized pinch of salt for now

Edited February 27, 2023 by Chesil View