Model Output Discussion - Spring Has Sprung

[Ice Day]

32 minutes ago, Uncertainty said:

Are you in then, for one last ride, for old times sake? 

A definite yes from me.  It's been yet another winter of massive letdowns, as they always seem to be these days, but a late February cold spell can still pack a punch.  There's some tentative uniformity between the ECM day 10 and GFS day 11, with rising heights up towards Greenland helping a pretty potent Scandi trough over in the days that follow

Confidence levels are of course extremely low at this range, but if the models are showing it, it's worth discussing.  For those that threw the towel in, you'll need to sit this one out! 

[ANYWEATHER]

27 minutes ago, Ice Day said:

Confidence levels are of course extremely low at this range

I think many on here will go a step further, Zero confidence on model output as regards a very cold spell.

[Ice Day]

Interesting early changes on the 6z with the jet digging a bit further south, leaving us with this at day 9

Based on this run, our Irish contingent will be raising an eyebrow at 198hrs

The days that follow show some snow for most areas around the UK.

With the jet going south, were now very much in slider territory at day 10, with heights looking to build over Greenland.

I'm enjoying the model consistency, if nothing else.  It's a very long way off, but it's a start. 

 

 

[BarnetBlizzard]

Did someone ask for low heights into Europe? 

[Hotspur62]

 BarnetBlizzard That would gives the alps a nice dumping and kick start the ski season again

[feb1991blizzard]

Nice.

[Ali1977]

So many discounting cold chances later in Feb even with a SSW - for no other reason than due to either dissapointment or to just annoy others - the 24/25th has been supported by the ENS for a few days now - the GFS op has flipped the last few runs too.   

[feb1991blizzard]

Huge SSW reversal.

Right from top to bottom.

Potential for Dec 1990 event.

Edited February 13 by feb1991blizzard

[Met4Cast]

 feb1991blizzard

Yes much better. As stated in previous posts I think late Feb/early March holds the best potential. 

Slow moving MJO phase 7 through late Feb > early March suggests Atlantic ridging retrogressing to Greenland & eventually a west based -NAO (GFS dets currently hinting at this broader evolution in the above timeframe) 

In terms of the AAM we still have a lack of poleward fluxing but with a major SSW & split there is a window of opportunity for blocking beginning to appear within the context of a very unstable polar profile. 

Not convinced on anything *prolonged* given the above but certainly potential for a cold spell at the end of the month. Blocking however might struggle to become sustained in the right places for long periods. 

[Ali1977]

 feb1991blizzard I’m pretty confident for something far better late Feb than is showing at the minute - I also expect we’ll see stronger METO wording with this ful on SSW - even though not guaranteed 

[feb1991blizzard]

 Met4Cast

I must admit (although haven't viewed this run (fully)), on previous SSW threshold meeting runs, the EPV flux has looked more equatorward than poleward, that is one concern.

[Met4Cast]

 feb1991blizzard Indeed, does make me wonder how much impact this SSW will have, current EP flux forecasts (GFS) suggest mostly EQ-Flux but these are based on the GFS det so change as frequently as that does. 

I really wish we had more data available in this area by other models.

[TEITS]

 Ali1977 I'm throwing my towel back in.

What I have noticed lately is for the last week of Feb virtually all GEFS ensembles suggest cold with very few mild runs. The amount of rainfall is disturbing though. Only yesterday I took a trip on my mobility scooter to see the nearby floods and visit my brother at the same time. The pic below was taken right next to a vast amount of houses. The river Nene is around 200 metres from where the photo was taken.

[feb1991blizzard]

 Met4Cast

There used to be epv charts on ECM op runs on the Berlin site but they've ditched them a few years ago.

[Ali1977]

Control heading the right way now too 

[frosty ground]

I’m pretty sure I’ve seen these runs before, didn’t December start with diving lows into Europe?

[In Absence of True Seasons]

 TEITS Worrying indeed.

Fear not, though. Because hosepipe bans will be in place come the first spell of 25c+ weather in June.

[CoventryWeather]

I'd take anything over this. Full day of rain again, full cloud cover. 

Atleast the latest GFS would give inland areas dry sunny weather. A few convective showers too which would be nice to see for a change. 

Edited February 13 by CoventryWeather

[carinthian]

Good Afternoon to all back in blightly. Just nearly choked on my Apple Strudel after reading GB News FB ,which tells you lot back home to wrap up warm as Britain to be covered in 8 days (NON -STOP)  which they highlight snow cover a foot deep with a 400 mile long wall and 32 cm to fall over Scotland on 28th February. I am not sure who feeds or writes this nonsense but you have to laugh at it. Anyway for a bit of fun I have attached the latest GFS run shown for months end. Of course I hope GB News analysis is spot on ! Meanwhile back in the land of the living, my daughters picture from Stockholm this morning still shows snow in the city . Its been on the ground for  well over 2 months now there. Their forecasters say March is going to follow in the same vain. Colder than normal. For much of this winter the models have continued to show cold entrenched to the NE  but with little appetite to spread South and West. Maybe months end ?

C

[phil nw.]

GEfs certainly going colder .These for Warks.

A pattern we see have seen many times at longer range in a mobile Atlantic setup but without Arctic heights., although not so much this Winter.

Chances of some seeing snowfall if this verifies for sure but i am always wary of it counting down as it is  ridging from an Azores high rather than blocking further north.Will it be solid  enough to get a really good Arctic outbreak or as we get closer ?It often happens, the 850s modify nearer time as gfs flattens the pattern somewhat.

Really this pattern relies a lot on the angle of the jet driving troughing far enough south at  a good enough angle. rather than from any Arctic blocking.

Let's hope we can get something from this to finish Winter off on a better note.

[Battleground Snow]

Afternoon all, 

Haven't posted for a while due to work, and other commitments.

I see a small window of wintery opportunity from the 21st - 27th via a Atlantic ridge, possibly making it temporarily into Greenland.

It's a shame we couldn't quite get enough amplitude on the mjo into 8, for something more sustained.

A disappointing winter overall with how promising the teleconnections were looking. Weakening Nino, east qbo etc, but we still had some great debates and analysis from the majority of posters.

A March wildcard with the potential SSW, but very uncertain how this will transpire at lower levels at this stage.

 

[Rain All Night]

15 hours ago, Rain All Night said:

12z deterministic runs, Tue 13th to Mon 19th (day 7)

Just to reiterate what I hurriedly wrote this morning, it seems that the GFS had once again been right to take a different path ahead of the other models, this time denying the possibility of significant height rises northwards of the UK.

After the passage of the next little Atlantic low through the UK, which looks like it will have its greatest impact around Friday morning, we will generally be seeing a struggle between high pressure trying to ridge up over the UK from the south, and low pressure systems from the west riding in over the top of this.

12z ensemble means, Tue 13th to Tue 27th (day 15)

From roughly 17th-21st Feb, as we're starting to see on the deterministic runs, ridging from our south may interfere with low pressure systems coming from our west. Thereafter, ridging may tend to move to our western side, while troughing may tend to occur on our eastern side - this has been the takeaway message from most ensemble suites over the past several days now.

0z/6z deterministic runs, Tue 13th to Tue 20th (day 7)

Following a naff couple of days, the little low out to the west will pass over us on Thursday and Friday and pop out on our eastern side. Thereafter we'll be caught in a struggle between high pressure from the south and low pressure from the west until at least day 7.

0z/6z ensemble means, Tue 13th to Wed 28th (day 15)

From about 21st Feb (day 8 ) onwards, GEFS is strongly and persistently suggesting that an Atlantic low will push from northwest to southeast into Europe, forming the "Scandi trough" that we have been seeing in the week 2 ensemble means for the last few days. ECM clearly sees this possibility as well, but is less willing to commit to it. GEM is more of a mess, as is often the case. How deep into Europe the low gets will determine whether there is any prospect of cold air being pulled over the UK.

Edited February 13 by Rain All Night

[KTtom]

I do agree with all signs pointing to a colder (won't take much) spell during the last week of February. Currently, northern coasts and hills should see some snow. Is it worth getting excited about?, going by the trend over the last couple of years, absolutely not. We are still looking 300 odd hours away, baring in mind how other cold spells this year have dwindled away as they got within the reliable, plus taking into account we are a stones throw from Spring, you can certainly understand people scepticism, doesn't mean they are winding people up! Some people on here have been seeing snow potential since September, some have never seen it.. the latter have been more accurate. 

Edited February 13 by Paul

[Severe Siberian icy blast]

We've been chasing fantom cold spells all winter do we actually expect to see anything of note months end? 

Id love it to happen but this year northern blocking has failed to get a foothold, the AO has been negative quite alot but getting the NAO to go negative has been tough.

And now we have people talking about a 1990 style easterly with charts that's over t200 hours is just laughable in all honesty because it does seem as if there's little realism in this place at times.

It will take something special to deliver in March and do really think this is a possibility? 

We have had several strat warnings so far and I've not seen a cm! 

[Dennis]

Knowledge to an SSW; it doensnt mean with one thats happened or happening always cold is forseen 

it depends on the downwelling from the strato into the tropo (also its target)

see to this : WCD - The role of North Atlantic–European weather regimes in the surface impact of sudden stratospheric warming events (copernicus.org)

its a puzzle that has to fit

AND ;at  the day when an SSW is happening NOTHING is already happening on that day ..... the stratocold needs to come down first 

So if we see cold late febr it isnt from the SSW thats forseen ....thats into midMarch if all is succesfull

 

 

Edited February 13 by Dennis