Model Output Discussion - A cold start to Spring?

[Mucka]

Perhaps it is a good thing to have such a relatively poor run dampen our enthusiasm. It is easy to get carried away seeing snowy chart after snowy chart while forgetting this is the UK we are talking about!

Let's take a breath, enjoy GFS pub run fun, and get ready to ramp tomorrow when ECM has taken the smelling salts. 

If by small chance it is right with such a rapid breakdown then let's hope the details change in between to better potential for more snow showers and a snowier more prolonged breakdown.

I could live with that.

Edited March 2, 2023 by Mucka

[Mark wheeler]

Navgem is pants . 

[Mucka]

1 minute ago, Mark wheeler said:

Navgem is pants . 

Navgem is pants come rain or shine.

The fact it agrees with ECM is a good sign.

[sheikhy]

Its a real shame and i dont mean to be negative as i genuinely thought the ecm was gona be a better run than the 00z with a slightly more southward push around 168 and 192 hours!!!especially after the ukmo and the 06z mogreps ensembles!!it what it is peeps live to fight another day but we defo need changes for the better tomorrow morning or according to ecm its gona be a non starter lol!!!!literally!!!!!

[KTtom]

To be fair, given the scatter for later next week in the Ens, it was only a matter of time until one of the ops went the much milder route... Have to wait until tomorrow to see if its a trend or just a 1 off.

[Rain All Night]

11 minutes ago, IDO said:

This morning's ensembles had the scatter where the 12z clearly was a possibility. We have had several cold ops rather than cluster switching, so a mild one was due (0z):

The ens trend was that temps would rise and the 12z shows the faster route. No quick recovery to cold if the 12z is right, as heights to the north and NW fade quickly. 

We have to see where this lies, see if there is a trend in the ECM ensembles (correction to the downwelling), and tomorrow whether other models pick this signal up. Sadly, it is within the bounds of options and the ECM scenario would be a very disappointing view from the garden path.

I posted this 24 hours ago and was then surprised to see the ECM not go mild on its 0z op run this morning...

Edited March 2, 2023 by RainAllNight

[BlueHedgehog074]

The 12Z JMA also drops the Scandinavian trough a fairly good way to the East of the UK with a clean looking Northerly early next week:

You can then see it becomes quite perilous with that Atlantic Low out West trying to nudge further East. But it manages to avoid the same path as the ECMWF with a little Low splitting off the main Atlantic Low. This little Low heads East/South-East through the far South of the UK into the nearby continent. A wedge of High Pressure re-amplifies in the Atlantic bringing the chilly/cold Northerly flow back:

The main Atlantic Low attempts to come back in, but a weak wedge of heights then develop over Northern UK and the Low has no choice but to slide South-East into France. Then drawing in Easterly winds over the UK:

 

The cold and wintry weather take victory. 

[NewEra21]

Just one run, but this is the UK and just goes to show we can never celebrate until the snow is falling outside of our windows.

[Gowon]

@Lukesluckybunch cursed it by getting too excited 

[Rain All Night]

Just now, Gowon said:

@Lukesluckybunch cursed it by getting too excited 

Actually it was Tamara's post a few days back that did it I reckon!

[IDO]

Just now, RainAllNight said:

I posted this 24 hours ago and was then surprised to see the ECM not go mild on the 0z this morning...

Yes, agree, from a statistical point of view and assuming no bias in the models, a milder op should have been more likely. Unfortunately, the ops suck at high latitude blocking and get it wrong too many times for any of us to have high confidence even with a full hand.

I would therefore not take the 12z ECM as the end, just we do not want to see the ens follow and GFS tonight go bust. As expected the rest of the ECM run is garbage.

[Stuie]

As comments are mainly about next Wednesday, the trend is there with the GFS less progressive. The weekends outputs (if not tomorrow) should give a clearer picture but here is the ECM/UKMO/GFS/GEM for T144

 

Totally agree with @Mucka about staying focussed closer to time but this does tie in with the NAO wanting to trend back towards neutral and has been the theme for many days showing that this wasn`t going to be a prolonged episode. The NAO is only based on the GFS so that`s 1 pinch  of salt.

The PNA, this is purely from my own observations of any correlation but it is now trending towards positive also.

All these are just model assumptions and if there are effects from the 2nd warming then all the above could easily be trash.

Don`t want to see the above being the trend on Saturday though (if you like cold that is for this spell,  March could throw another but...)

 

[January Snowstorm]

I don't believe the ECM has this right at all. But history tells me the best cold comes from heights over Greenland waxing and waning towards Scandi. This is where historical cold spells have come about. For me the heights over Greenland weaken across all models at day 6/7 and the gfs / ukmo rely on little wedges that work tiny miracles. Of course a mix of ecm and ukmo would be quite a good result and a meeting of minds often happens!!

So for now everything is up in the air, but the favourite option is cold

[Purga]

A ridiculously mild run from ECM to flatten everyones' spirits and end up with a nice fat Bartlett after the short cold snap is easily blasted away.

Let's hope the ECM ENS suite is a bit more encouraging!

[Penicuikblizzard]

24 minutes ago, seabreeze86 said:

Let’s hope so Ali because it’s is a disaster wasn’t expecting that at all. It’s on its own the ECM so will probably we wrong 

ECM was king of the castle last night but tonight it is wrong? I would trust the ECM before GFS right now 

[NewEra21]

I think we've all been scarred far too many times to just discount this ECM run, definitely don't want to see it repeated on the 00z run or the UKMO or gfs. As we know how quickly things can go wrong once we hit that road.

Edited March 2, 2023 by NewEra21

[That ECM]

Looks like a ridge going nw I’ll get my coat.

[nick sussex]

This looks like a major pattern change in the USA and if that’s the case best to wait to see if this new trend verifies and the downstream impacts .

NCEP in their monthly forecast for March forecast a change in the central and eastern USA caused by the MJO.

This doesn’t mean its curtains for us and it could well be that we end up with more blocking to the north .

What would be nice is if we can avoid any mild crud during the change ! 

[seabreeze86]

2 minutes ago, Penicuikblizzard said:

ECM was king of the castle last night but tonight it is wrong? I would trust the ECM before GFS right now 

All models will be wrong at 144hrs. The UKMO wobbled yesterday the ECM today and the GFS just continually wobbles

[DAVE_ALLEN]

The cold air is coming. We just need to clear away the low pressure coming south on Sunday/Monday. 
By Monday showers IK the blue area should be snow and hail. And these will move steadily south on Tuesday.  
 

Alex Deaking had it all as rain on Sunday but I think the precip in Scotland could well be wintry by then. Especially over the hills ! 

[Updated_Weather]

Why is it when one run goes rouge? People panic. Wait until we see the ensembles. 
One det run doesn't mean it's right. Remember this is just one option.

So far it's UKMO, GFS vs ECM. 

We await the ensembles.

[Purga]

The trouble is when there's virtually complete cross model agreement on a decent cold spell & then just one rougue mild spoiler run gets thrown up, completely unexpectedly......

We all know what happens next !

[Phil Blake]

6 minutes ago, Purga said:

A ridiculously mild run from ECM to flatten everyones' spirits and end up with a nice fat Bartlett after the short cold snap is easily blasted away.

Let's hope the ECM ENS suite is a bit more encouraging!

Isn't a Bartlett a persistent high pressure cell over Iberia/Europe/bay of Biscay during winter? Pressure rising in this area doesn't automatically make it a Bartlett unless I'm mistaken 

[on the coast]

Just now, Purga said:

The trouble is when there's virtually complete cross model agreement on a decent cold spell & then just one rougue mild spoiler run gets thrown up, completely unexpectedly......

We all know what happens next !

I know loads of people knock the GFS18z but in the past has been good to spot a change. Lets see what it looks like later.

[Stuie]

1 minute ago, nick sussex said:

This looks like a major pattern change in the USA and if that’s the case best to wait to see if this new trend verifies and the downstream impacts .

NCEP in their monthly forecast for March forecast a change in the central and eastern USA caused by the MJO.

This doesn’t mean its curtains for us and it could well be that we end up with more blocking to the north .

What would be nice is if we can avoid any mild crud during the change ! 

Nice info Nick. The AO is totally confused at the min but can see why the changes (for X period of time). I believe currently the NW is the cold theme and ties into the current PNA obs.

AO - 

Seems everywhere is messy.