Model output discussion - the beast arrives

[Jayfromcardiff]

1 minute ago, Nick L said:

Those snow depth charts are completely inaccurate. No idea what algorithm they use but it's nonsense!

Any idea on potential snow amounts from the "blizzard" on Thurs/Friday? Obviously rough estimates.

Hopefully the cold manages to hold on longer.

[MattTarrant]

3 minutes ago, Ben Sainsbury said:

For what I see the ECM 12z will have produced some of the largest snow totals of all the runs so far.

Exceptional chart, the hardest hit being the Dublin area receiving almost 65cm of snow between Thursday and Saturday. Whilst most other places looking in excess of 20-25cm.

I do believe they are horridly inaccurate. The In & cm depths are completely different 

[Derecho]

Bizarre ECM with a very deep low to the south of Ireland, not sure about the plausibility of the run given how deep it is. Anyway some precipitation charts and dew point charts for the ECM from this event.

 Friday morning
 Anywhere to the south of the black line has dew points above freezing

The precipitation advances north, but the cold air digs in

 So the 0C dewpoint line doesn't advance north much

Then the 0C dewpoint line marches southwards again. South eastern areas would have another borderline rain/snow event associated with the low at T144.



Small changes and these events could be all snow.

Charts can be accessed here:

https://weather.us/model-charts/euro/england/dewpoint-f/20180303-1200z.html

 

Edited February 25, 2018 by Quicksilver1989

[Eastnorthwest]

I say all the models now struggling beyond T 96 today and will from now on in while the block holds ,and remember once the cold gets established it will take a lot of shifting

All good I say for coldies

[Eastbourneguy]

The modelled snow depths by Friday on the 12z ecm below.

Looks like Eastern Ireland is going to get walloped! 

For England and Wales, this run models all ppn falling as snow for the first 6 hours before ice pellets/freezing rain comes into the mix in the far south (roughly 40miles from the coast), snow further North. Then a return to all snow, even on the coast as the ppn begins to move northwards,  up the spine of the country and even making it to Scotland. 

 

[Frosty.]

Cold air digging south again having persisted across northern uk on the Ecm 12z..very good to see!..a great finish with another reload!

Edited February 25, 2018 by Frosty.

[Stuie]

Well T216 on the ECM looks like a reload of the cold.

[pages]

7 minutes ago, Dennis said:

Models going to show massive run to run differences with MJO now more amplified after being predicted to go into COD a couple of days ago.

[Captain Shortwave]

      

All of a sudden we are back in the easterly solution, okay we lose the deep cold but at this point we would have barely lost any of the snow from this week. It would be very cold at the surface and with 850s below 0C then the fronts which approach the UK should be falling as snow. Between these there could be a lot of cloud but still tonights ECM would keep the UK cold to at least day 10.

Despite heights lowering, we keep surface heights to our north all the way through which allows low pressure to be steered further south, even at day 10 we have a deepening trough over Scandinavia with low pressure in the Atlantic undercutting a wedge of heights south of Greenland.

Edited February 25, 2018 by Captain Shortwave

[Day 10]

Cold fighting back too!

[Snowy L]

Very good ECM OP. Does look like we will see a milder spell on Sunday/Monday but hopefully we see the mean go back down again after that.

[Mike Poole]

This looking like a total white knuckle ride, but the ECM T240 has us back in the cold, unstable flow, bring it on!

 

[Rayth]

Snow is naturally a headline grabber but some of the wind chill totals for next week are a touch on the concerning side , especially when it’s not widely talked about in the none weather geek community / social media etc 

[BLAST FROM THE PAST]

2 minutes ago, Day 10 said:

Cold fighting back too!

No surprise.....it will stay with us

 

BFTP

[JBMWeatherForever]

Models trending back to a prolonged spell of cold again for all after next weekend. Some milder air in the south for a time but blink and you will miss it. Severe Easterly spell followed by Blizzards in places (maybe two Blizzards), followed by renewed cold weather and either very cold north easterly's or the Polar Express joining in on the party. Next week (5 to 12 March) may also see some very low minimums under the slack air once the cold has re-asserted itself.  EPIC !

[Daniel*]

Very good trends this evening pendulum swung back to an extended cold outlook limited to no real warm up. Southern half of country at risk of turning less cold very briefly.

[Mr Frost]

It really is never ending isn’t it? Incredible, phenomenal, unbelievable and just out of this world charts again from the ECM! 

Below latest ECM charts from 28/02 to 02/03 which for large areas of Scotland, England, Northern Ireland, Wales and Ireland contain...frequent and heavy snow showers, bitter cold, blizzards, strong winds from the East/North East and South East, ice days, frosts, danglers, streamers, more organised bands of snow pushing through and significant snowfall in some of the most populated cities all over the UK and Ireland...some of this is happening in the Meteorological Spring!!!! Honestly if you are in a Yellow or Amber warning area set for 10 or 20 cm of snow or even if you get 1cm get out into the garden and at least roll about in it.  This is a proper Beast from the East! 

Have a good night all! 

 

 

 

[nick sussex]

The outputs tonight show it’s a complicated set up and why it’s best to wait a few more runs because you can see the struggle of the milder air to displace the entrenched cold over the UK.

The 850s are not so important once you’ve got the cold in , it’s not necessary to see deep upper cold to deliver frontal snow.

 

[terrier]

Great run from the ecm tonight. A slight milder blip in the south next weekend before we are all back into the cold airmass. Which definitely ties in with GP’s thoughts the other evening. We’re he did say that if any milder air got in it wouldn’t last long. And the ecm ties in with that statement this evening. 

[Frosty.]

15 minutes ago, terrier said:

Great run from the ecm tonight. A slight milder blip in the south next weekend before we are all back into the cold airmass.

That slightly less cold blip across southern uk might get squeezed even more on subsequent runs..fingers crossed the southward adjustments / corrections continue!

Edited February 25, 2018 by Frosty.

[nick sussex]

What’s interesting about both the ECM and UKMO.

These are the first main outputs from the last few days to split energy east .

This suggests they could have underestimated the forcing from the north and ne and only closer in have the models starred to resolve this .

Its for this reason why historically these set ups gets corrected south nearer the time.

Of course there are always exceptions , however  if the energy split gathers pace then it’s likely to happen earlier than currently projected by the Euros.

We’ll see over the next day what happens.

Edited February 25, 2018 by nick sussex

[Summer Sun]

NMM tries to introduce some less cold air later in the week this might be limited to the south and not last overly long

[Chesil View]

Just now, Frosty. said:

That slightly less cold blip across southern uk might get squeezed even more on subsequent runs..fingers crossed the southward adjustments continue!

Yes Frosty I thinks there's a while to go yet on this before we are at a point  nailing the final outcome. Further ahead looking good on both ecm and gfs albeit via differing routes

[Summer Sun]

UKMO extended looks a wee bit calmer and drier still a few showers around but not as widespread

 

Edited February 25, 2018 by Summer Sun

[nick sussex]

Just now, Summer Sun said:

UKMO extended looks a wee bit calmer and drier

 

That looks very good, easterly flow still in place and some harsh frosts over snow cover .