Model Output Discussion - Spring Has Sprung

[carinthian]

Good morning from a fast snow melting Alps. Yes, freezing level 2500m ! Oh , this mornings models , any the wiser ? Definitely a change taking place this week  but exact details not yet fully determined. GFS/and the French model blow up the low over Ireland Thurs/ Fri , so this would delay any cold. UKMO/ ICON sinking the low to form a European trough which would allow cold to dominate much quicker. ECM sort of in between but looks more in line with the German/ UK model at this instant. Looking at the fax input for Thursday, I would think at this stage, rain for the south with snow in the mix further north. If the low deepens further , possibly the  precipitation could advance further north. However, if the UKMO model proves to be correct , there will be a big up tick for snow potential be be further south.

Could be a big week coming up to see if the winter can get a proper grip across The British Isles. Meanwhile, Central European stays on the warm side for a bit longer.

C

Edited February 5 by carinthian

[AO-]

 JimBob

Over a largely extended snow cover it may be very cold. Back in March 2005 over fresh snow cover here -20 in Holland. The EC is great for Britain I would say. Watching the snow cover adding up with the hp. 

[Lukesluckybunch]

1 minute ago, AO- said:

Over a largely extended snow cover it may be very cold. Back in March 2005 over fresh snow cover here -20 in Holland. The EC is great for Britain I would say. Watching the snow cover adding up with the hp. 

Which period do you see it as snowy for the uk AO- 120-168?

[sheikhy]

Absolutely brilliant for the whole of the midlands this morning at only 72 hours!ukmo remains south!!ecm has gone further south and gives midlands and wales a walloping!!arpege a little further north though!!poor gfs seems to be on the ropes this morning!!best thing is whatever snow does fall on ecm and ukmo should stick around for a while!!

[IDO]

As for the GFS, my usual first look, I dismissed that as unlikely, almost certainly an outlier at 2m temps alone, for London:

It is the worst-case scenario and not worth spending too much time analysing.

The models have been rock solid on the Wednesday frontal snow for a while. The questions have been, how long will it stick and to what ASL do you need to be to get the heavy settling stuff?

[Lukesluckybunch]

Good old UK high at day 10

[sheikhy]

 MattStoke any accumultion charts with that mate?!!anyone living in the mids/wales/yourkshire area should be excited this morning if snow is your thing!!hopefully it dont change much lol!!

[winterof79]

 Dennis With you on that Dennis

[IDO]

 Lukesluckybunch The mean has been rock solid for a UK high for a while. The trough has always been mobile, and any snow needed to be Wed-Sunday before the pattern moves to UK high. The GEFS mean, D8-16:

[Gowon]

A very cold high - the south easterly would feel freezing 

[TillyS]

1 minute ago, Lukesluckybunch said:

Good old UK high at day 10

Unfortunately it’s transient, moving west to east with the Iberian High pressure still evident, and leaving the UK increasingly susceptible to milder air on its western side:

Day 8:

Day 9:

Day 10:

A big downgrade from yesterday’s ECM runs. The model has not covered itself in glory these past few weeks.

 

As for the mid-week front, still considerable uncertainty. ECM only has snow for a time in the north. A lot depends on how far the cold will dig in ahead of the warm front. Until now the UKMO has had it the cold pushing right down across the whole country, but the GFS isn’t keen on this scenario and I notice the latest Meteo Group / BBC forecast are backtracking somewhat.

 

[sheikhy]

@MattStokejust checked!ukv gives me 21cms of snow thursday!!!madness!!never seen those totals forecasted for my area from the ukv!!

[Lukesluckybunch]

1 minute ago, TillyS said:

Day 10:

Probably a new surge of waa..which could lead to something exciting..but that would be a slow process I think!

[MattStoke]

 sheikhy it’s one of the few models that actually tends to under do snow accumulation. Rarely shows any for me even when I get plastered.

[Dennis]

could be a good snow-event at the horizon

[sheikhy]

 MattStoke exactly mate!!!!lets see!!!looking good though for us as it stands!!

[winterof79]

Central Northern England looks like a sweet spot to me for the first tranche of snow North midlands too

Edited February 5 by winterof79

[TillyS]

7 minutes ago, IDO said:

It is the worst-case scenario and not worth spending too much time analysing.

A dangerous approach to model output analysis that one.

Best not to dismiss one of the big three models, especially the best performing of the three, just because it doesn’t serve up what we want to see.

Generally this is the time to be cautious and to ask ourselves, ‘now how might this not go to plan?’ Or, more scientifically, ‘how might the biggest teleconnection of all namely AGW, mess up what looks like a good synoptic setup?’ Marginal boundary snow over high ground is already complicated, and for it to produce much meaningful at lower levels we would need the cold to dig in hard ahead of it, as per recent UKMO’s (but are they starting to wobble?).

[Lukesluckybunch]

4 minutes ago, sheikhy said:

MattStokejust checked!ukv gives me 21cms of snow thursday!!!madness!!never seen those totals forecasted for my area from the ukv!!

Without bias..what's your feeling on Thursday Friday sheikhy,do you see the front moving South north or..staying as it is?

[Nick F]

I guess if UKMO/UKV is the most southerly scenario and we discount the GFS then Midlands north look the best bet Thurs/Fri for snow on the northern edge of the rain moving in from the W/SW. Here's UKV:

A lot of uncertainty after this week, but it does look like low pressure will clear east on to the near continent to allow high pressure to build in the vicinity of the UK, a cold high. Would disregard the 00z GFS, which looks like it's on the mild end of the spread because it brings in the Atlantic.

Edited February 5 by Nick F

[Lukesluckybunch]

What snow totals we looking at from the ecm?

[MattStoke]

 Lukesluckybunch

[sheikhy]

 Lukesluckybunch hmmmm!!!!!!its so finely balanced in terms of a 100 miles further south or north!!if we had a colder wedge of air ahead of it say -10 850s then i would have said there probably wont be another push north and if anything it shall be further south!!but because the air ahead of that low is not exactly frigid then i can discount it pushing further north than forecasted!!if i was south of lets say northampton i wouldnt get my hopes up to be fair!!

[TillyS]

11 minutes ago, Nick F said:

Would disregard the 00z GFS, which looks like it's on the mild end of the spread because it brings in the Atlantic.

Well, the 18z had the same and it was by no means an outlier. I am wary of disregarding, or worse dismissing, the GFS.

The direction of travel with the ECM is also not trending right. It has backed right away from an easterly: second time in a month that it has done this.

The problem remains that there is no northerly blocking and persisting high pressure over Iberia. There’s not much to hold back the Atlantic from pushing through, which is effectively how the ECM is now modelling it days 8-10 with the high gradually transiting west to east.

I suspect a cold spell of a few days with transient boundary-edge snow for the Midlands northwards, turning to rain for all except the higher ground. The south will be predominantly milder. And I’ll leave it there. Heading to the Scottish mountains end of the week so hope I see some snow.

 

[Nick2373]

 

00z well not much to write home about, cooler from the 11th onward to the 13th then hints of a height raise from the 15th Feb cold rain coastal areas South snow the usual higher elevation the further North you go