Model output discussion 10/02/21

[LRD]

ECM Ensembles in graph form:

Op pretty representative of the mean until Day 8 when the op becomes amongst the coldest members

Aberdeen ensembles

Scotland in for a longer cold spell on this evidence (no surprises there I guess). 

Easter Day mildness has increased for the south. Easter Monday/Tuesday coldness has also increased

[Mike Poole]

Well this is interesting, there are 6 ECM clusters in the T72-T96 timeframe. SIX!

Just to unpack that a bit, we know now that we’ll be under -8 uppers or lower by T96, so which is the one we want, I think Cluster 2 looks to have the low digging in to the UK the most, so I’ll go for that one, please!

[minus10]

17 minutes ago, LRD said:

ECM Ensembles in graph form:

Op pretty representative of the mean until Day 8 when the op becomes amongst the coldest members

Aberdeen ensembles

Scotland in for a longer cold spell on this evidence (no surprises there I guess). 

Easter Day mildness has increased for the south. Easter Monday/Tuesday coldness has also increased

The incredible thing here is the cliff edge dramatic descent to cold. No gradual cooling as winds veer from sw to nw behind a cold front which is often the case in winter , particularly down south . That is almost a 20 degrees drop at 850 hpa level !

[Empire Of Snow]

39 minutes ago, Jon Snow said:

I’ve seen things you people wouldn’t believe..yes I remember that famous ECM run and that famous comment..WTF I don’t believe it!. ....but anyhoo, we are about to be plunged back into the depths of winter with cross model support..no ifs..no buts...it’s going to happen..enjoy the ride..if you’re a coldie of course!  

 

 

I feel a bit naughty. It was you, me and a few others fellow members here that started chasing this Arctic blast when it was deep in FI. But for some reasons (GFS is certainly very good catching this kind of signals in spring) it felt that will verify. I hope we will have at least a couple of heavy snow snowers and not just the bitterly wind chill. It seems also that conditions will improve towards the 12th April, we all know that independent hospitality sector was badly hit and they'll need the support. First comes the weather support. 

[ANYWEATHER]

30 minutes ago, minus10 said:

The incredible thing here is the cliff edge dramatic descent to cold. No gradual cooling as winds veer from sw to nw behind a cold front which is often the case in winter , particularly down south . That is almost a 20 degrees drop at 850 hpa level !

The Dramatic drop in temperature suggest a polar Front ..they are rare to the UK especially in April we have to go back to Jaunary 2004 for anything like  this....!?

[ICE COLD]

Bloody Nora the GEM hasn’t been mentioned tonight ? Look at how cold it is at just T84 . -14s fairly widespread. Stonking output again tonight

[Mike Poole]

7 minutes ago, ICE COLD said:

Bloody Nora the GEM hasn’t been mentioned tonight ? Look at how cold it is at just T84 . -14s fairly widespread. Stonking output again tonight

Yes, that is impressive, annoying that the GEM is not available on Meteociel at the moment cause of the fire, so many of us are not looking at it.  It is a good model and needs to be taken seriously when working out what exactly this cold spell is going to deliver...

[ICE COLD]

1 minute ago, Mike Poole said:

Yes, that is impressive, annoying that the GEM is not available on Meteociel at the moment cause of the fire, so many of us are not looking at it.  It is a good model and needs to be taken seriously when working out what exactly this cold spell is going to deliver...

Also just looked at the ECM  mean a little closer on the 850s and the -9 line is clear of the south coast with 3/4 of the country -10 or lower . Could be one of these where it upgrades further at short notice

[ANYWEATHER]

This maybe a TextBook perfect April cold spell ...

[Methuselah]

33 minutes ago, ANYWEATHER said:

The Dramatic drop in temperature suggest a polar Front ..they are rare to the UK especially in April we have to go back to Jaunary 2004 for anything like  this....!?

Don't forget 1970, 1975 and 1978 -- they all delivered?

[Northernlights]

2 minutes ago, General Cluster said:

Don't forget 1970, 1975 and 1978 -- they all delivered?

And early April 1968  The front crossing the Firth from the north  had cloud that was very black and menacing after a fine day harrowing dusty seed beds.

[Don]

I'm nearly on board now but will give it another 24 hours! 

[lassie23]

I'm looking forward to some beefy showers next week oh and roast beef for Easter dinner of course.

[Methuselah]

8 minutes ago, Northernlights said:

And early April 1968  The front crossing the Firth from the north  had cloud that was very black and menacing after a fine day harrowing dusty seed beds.

I remember that one well: from 20C to lying snow, in a little more than two days!

[Mapantz]

It's an Arctic front, not a Polar front. That's a different kettle of fish altogether.

Nothing unusual either.

[Allseasons-Si]

32 minutes ago, Don said:

I'm nearly on board now but will give it another 24 hours! 

You should be on board now as it looks nailed on now with cross model agreement

OK,...i have said it now and all this will blow further east ha ha

i am looking forward to some interesting weather as it's been a while

just to add about the models,no one has mentioned the 12z ICON...

...this one looks to have a reload at 180 too just like the other models and we need to keep an eye on a low exiting the UK around that timeframe as it shows a cold wrap around on it's NW flank and there could be quite a bit of snow on it(hatched areas)

there is not much else to add as others have covered all basis in here,we are getting close now to some interesting weather,...camera will be charged and ready for some good cloudscapes and hopefully some thundersnow thrown in for good measure

have a super bank holiday everyone as it looks OK up to bank holiday Monday with some decent-ish weather

take care all

P.S,...nice to here from you again @MATTWOLVES

 

Edited April 1, 2021 by Allseasons-si

[ICE COLD]

-11 as far south as London at just T90 of the gfs 18z . 

[Scandinavian High.]

4 minutes ago, ICE COLD said:

-11 as far south as London at just T90 of the gfs 18z . 

I really can’t believe what I’m seeing we have had bbq out just few days ago and now we look to be rolling back in to winter I’ve haven’t seen nothing like this my self..

[Allseasons-Si]

5 minutes ago, ICE COLD said:

-11 as far south as London at just T90 of the gfs 18z . 

Yes at 90 the gfs 18z has some snow for the SE

then that wrap around low towards 180 have the colder air digging in to the NW flank with snow showers for the NW...

all speculative at this juncture of course.

[Don]

28 minutes ago, Scandinavian High. said:

I really can’t believe what I’m seeing we have had bbq out just few days ago and now we look to be rolling back in to winter I’ve haven’t seen nothing like this my self..

I think the closest I've seen to this is 1989, when it was warm during late March (albeit nowhere near as warm as the last few days) and then plunged into winter early April.

[minus10]

This low crossing the country next week is one to watch. The 18z gfs shows it further south and slower at leaving our shores. As a result there is not such a significant cold high moving in after resulting in less risk of severe frosts (although there would still be some frost probably) which would i'm sure be a relief to gardeners and growers. However it is a volatile situation which could all change by the next run...

18z 12z 

 

18z  12z 

[feb1991blizzard]

31 minutes ago, Allseasons-si said:

Yes at 90 the gfs 18z has some snow for the SE

then that wrap around low towards 180 have the colder air digging in to the NW flank with snow showers for the NW...

all speculative at this juncture of course.

And then an Easterly

[Iceman2606]

Pretty crazy to still be seeing these insane GFS perturbations at only 4 days away LOL! P10 pushing -20 at 850hPa for some parts!

[Don]

1 minute ago, Iceman2606 said:

Pretty crazy to still be seeing these insane GFS perturbations at only 4 days away LOL! P10 pushing -20 at 850hPa for some parts!

That would be record cold for April surely?

[Jordan S]

From very impressive temperatures that are like june for central and southern parts of England and Wales to unusually low temperatures for April for all that are more like January in just a 5 day period, the change as most know is during Sunday night into easter monday morning after a largely dry, sunny and relatively mild day for many on sunday, northerly winds arent unusual at this time of year ofcourse but the resulting air over the uk from the synoptics for Easter monday certainly are unusual.. 

as a quick example of the synoptics for monday here's the Gem and Gfs upper air temperatures, values of slightly below -10c likely in the north or at least Scotland for a short time but close towards -10c likely in parts of the south too..

Gfs..

Gem..

My update largely similar to my last but slight changes.

Much colder upper air temperatures moving south along with temperatures significantly colder close to the ground behind a squally cold front on sunday night into monday morning, this clearing the south coast around midday, most showers around coastal areas but quite a lot of them inland too and falling as snow for many inland areas to lower levels especially in the north, the showers may be sleet for some in the south but some of them falling as snow here to lower levels too, ofcourse this very likely on higher ground here above 150m though any accumulating snow mostly likely for high ground of northern England northwards but some temporary small coverings a possibility further south to lower levels in any heavy showers before melting once they clear.

Easter monday 12pm..

6pm..

Along southwestern, southern coastal areas of England more likely a mix of rain and snow, then we have the likely hail showers in some areas aswell possibly in the form of graupel in some of them, thunderstorms likely in a few places these especially for Scotland, impressive rainbow photos I think are on the way for some.. daytime maximum temperatures probably 3-7c for most of the south, 1-4c for parts of the north and slightly below 0c locally in Scotland. Though temperatures dropping lower than these for some in showers.

2m temperatures..

some places will see no showers at all and apart from all this it will be sunny for many but feeling cold and very cold in the strong wind during the day and hard frosts for many on monday and tuesday night.

Temperature possibly down to around -10c in the coldest places of Scotland on monday night.

During tuesday similar to monday for many, but probably more rain and snow mixed for the south in any showers but snow likely to continue to fall to lower levels in the north, thunderstorms possible again, though perhaps less of them than monday but sunny and cold between and away from showers. Maximum temperatures at the moment likely to be 5-8c in most of the south, locally in Scotland once again they may stay just below 0c with other northern parts having 2-6c.

Overview..

One or two disturbances in the flow are a possibility too giving the potential for a longer spell of sleet and snow for larger areas though the emphasis at the moment is on showers rather than anything organised.

Not much change to what I said on wednesday from midweek to the weekend so a shorter update.

A less cold airmass still likely over the uk midweek so drier with any precipitation more likely of sleet and or rain in the south and same for the north aswell at least to lower levels except possibly Scotland.. similar for Thursday and Friday though the snow chance may increase in some northern parts again also potentially very windy in some places with winds rotating around an area of low pressure probably moving southeast over or just to the east of the uk.

 

Next weekend though this may change as it's a long way out but fairly likely now high pressure to the west or southwest moves east or northeast into atleast southern parts of the uk during the 10-11th possibly more on sunday and monday with drier weather returning to the south and although it may be frosty at first temperatures quite likely rising..

Saturday 10th..

Sunday 11th..

12th..

Edited April 2, 2021 by jordan smith