Model Output Discussion - A cold start to Spring?

[MATTWOLVES 3]

Remember yesterday! Some were saying this is dead in the water..no chance of snow.. bone dry!

Fast forward 24hrs and we have areas of Snow possibly Monday night into Tuesday...we then have a feature threatening the South mid week...before another set of fronts try to push milder air in on Friday! Now the latter one I feel as a little more oomph about it.

Big question is how far North will this system push! I think we are seeing the PV helping to push those colder uppers from the NE back again at times. I feel this is going to be very stubborn..We could be about to see the 2nd imprint on our conditions very shortly due to that strat warming event last weekend. 

Snow could crop up in a fair few places these next few days and I feel the met will be having to issue further warnings before much longer. Some areas could see a real dumping of snow...I would be very suprised if 2 significant warming events which have brought this cold will be blown away that quickly.

I feel tonight we are on the cusp of something potentially very decent...im not gonna say epic...and curse it,but there's a fair few miles in this saga to run just yet.

Hey folks...tell the missus you may be working nights next week! Give you a chance to do a little lamp post watching

Until then be prepared to expect the unexpected 🫡

The other day I said many of you may have set fire to the laptop..but tonight,I feel there's been a little swagger in ya

Ohh and a lovely little UKV for something interesting midweek into Thursday. I think @sheikhy may like this..a fair few of you will I would imagine 

Edited March 5, 2023 by MATTWOLVES 3

[CoventryWeather]

10 minutes ago, Tim Bland said:

It’s there on all models. This is driving the front south that we have been discussing turning to snow on the back edge tomorrow through to Tuesday morning 

Thanks. 

Regarding the models, I still feel some northwards updates are expected over the coming days with respect to the system on Wednesday. The ones on Friday are likely to be pushed a touch south. Anyone saying the weather is dry or all against snow and cold probably looking at the wrong charts. Plenty of activity for everyone this week, some will see more than others.

[sheikhy]

Anyone got ensemble graphs for mogreps and ecm 12zs?!!

[geordiekev]

4 hours ago, Man With Beard said:

Mike there's nothing like the Atlantic running into an NE flow to cause absolute chaos, is there! 

Where is FI right now? T24? T36?

Yep, like the drum I've been banging for a while, tilt your devices to understand the current situation, low pressure systems ARE NOT flowing accross USA and then the Atlantic. They are flowing West from the cold tPV to our North & then doing u-turns

 America is devoid of systems moving West to East, so throw the rule book out as the geographical tweaks programmers make are skewing outputs 

Edited March 5, 2023 by geordiekev

[Rob 79812010]

I've been lamppost watching for as long as I can remember! Why do we do this??

[StingJet]

27 minutes ago, sheikhy said:

Anyone got ensemble graphs for mogreps and ecm 12zs?!!

Will these do bud?

 

Edit: Added GEFS ENS 12z in for good measure

Edited March 5, 2023 by StingJet

[nick sussex]

The ICON makes yet another change on its 18 hrs run .

I’ve never seen such drama over modelling the upstream pattern at such a short timeframe .

[tight isobar]

Decide what ya will on the 18z gfs rollout!... but 1 things for sure- after the op has trickled out, ya can now start looking at supporting data.. if it’s precipitation type you want to evaluate. And strictly for personal preference, the Arpege is a worthy flow at- 24/48 hrs out......

[sheikhy]

8 minutes ago, StingJet said:

Will these do bud?

 

Perfect mate!!!!hmm seems to be some stragglers extending the very cold air all the way till the 12th!!!

[Tim Bland]

18z gfs about 50 miles or so  further south so far, see below comparison t+60

[geordiekev]

9 minutes ago, nick sussex said:

The ICON makes yet another change on its 18 hrs run .

I’ve never seen such drama over modelling the upstream pattern at such a short timeframe .

Because the models, as they get tweaked to make up for geographical accuracy shortfalls, havn't seen this pattern before. I think we saw similar modelled in December but it never came to fruition.

If anyone can find the current outputs in the Archive good luck, bc in my 14 years model watching, I've never seen a USA set up as has just verified

Edited March 5, 2023 by geordiekev
Typo

[tight isobar]

6 minutes ago, nick sussex said:

The ICON makes yet another change on its 18 hrs run .

I’ve never seen such drama over modelling the upstream pattern at such a short timeframe .

.. it’s as- if the German mod is “ for spite “ at somehow finding and ekking out as much west based Atlantic and geographical upstream  drama as possible!!!.. imo at short / mid range .. it’ trumps the American model for made up energy!!!

Edited March 5, 2023 by tight isobar

[Snowy L]

6 minutes ago, sheikhy said:

Perfect mate!!!!hmm seems to be some stragglers extending the very cold air all the way till the 12th!!!

It looks a lot worse than the complicated reality imo. In Edinburgh the average remains at -5 or below throughout. Small corrections South and the same could end up being true for much of England.

 

 

Edited March 5, 2023 by Snowy L

[Ali1977]

A much more potent LP on this run, which could be better for the north Thurs/Fri  

Midlands south not so good, although a small Shift could make changes in where/where not gets

Edited March 5, 2023 by Ali1977

[Tim Bland]

Slower progression / better angle of attack late Thursday …

[Snowy L]

I've noticed a few times now where the further South Wednesday's low is modeled, the further North Thursday's low is? Any reasons for this, would think if Wednesday is further South then Thursday should be too. It's happened on the 18z, not a good run this, game over for England and Wales by Thursday night.

 

Edited March 5, 2023 by Snowy L

[Evie Aviation]

I’m in Edinburgh on holiday, fly back to Heathrow Wednesday 6pm. Hoping I see some snow somewhere just want to say thank you to everyone for your interesting posts. For someone like me who loves to read and learn, this thread is fascinating. Good snow hunting everyone 

[MattStoke]

18z further south mid week and further north late week.

[tight isobar]

 of Note this @even 78 hrs via the gfs 18z- the notion of blocking formats  out wide- now starts effect jet modelling- And Will be the obvious bearer of 850 overhead penetration!.. anything after this is pretty fraught ... for the angle of holding or folding!!!

[Snowman.]

Just now, MattStoke said:

18z further south mid week and further north late week.

You can hear the faint cry of southerners..

[MattStoke]

1 minute ago, Snowman. said:

You can hear the faint cry of southerners..

Midlands south really. These fronts so rarely track right for the Midlands southwards. Almost always dive off into France or blast through into Northern England.

[CoventryWeather]

All change by the morning, why are we worried about a single run? Models are struggling with the low - they will do until at least Tuesday. No need to stress.

[geordiekev]

5 minutes ago, Snowy L said:

I've noticed a few times now where the further South Wednesday's low is modeled, the further North Thursday's low is? Any reasons for this, would think if Wednesday is further South then Thursday should be too.

We are in a weird set up where the lows aren't spawned from USA but a result of cold being dragged West from our trop PV. The models really ain't a clue if it's a clean flow, disturbances or how much forcing from the rotated bizarre Canada fed Greeny block.

As I've said before we're in now casting territory given the forecasting changes between 24h periods have huge inaccuracies 

Edited March 5, 2023 by geordiekev
Typo

[The Enforcer]

4 minutes ago, MattStoke said:

18z further south mid week and further north late week.

I predict the 00z will be further north mid week and further south late week. Then the reverse for the 06z and so on.

[Tim Bland]

Might be wishful thinking but is there a chance the snow line moves back south ? Look at the progression of the cold and how it stalls then shifts south ..

Edited March 5, 2023 by Tim Bland