Model output discussion - after the beast, what next?

[Nick F]

General agreement on an upper vortex splitting from tropospheric PV over N Canada and moving SE with a collocated surface low pressure system towards NW Iberia during the week, but when it gets to SW of the UK, differences on how far north or south the upper/surface low will be - which impacts how far south the cold air being pulled west out of Scandinavia gets.

GFS and UKMO further with north the low and cold end of the week compared to EC, so GFS is showing snow confined to Scotland and perhaps higher parts of N Wales and N England. EC on the other hand has snow event as far south as Wales and Midlands next Friday night / early Saturday.

Until post day 6 position of the upper/surface low out west is firmed up on, then difficult to know where is in the frame for potential snowfall from mid-week next week. Though northern areas most favoured and good chance southern areas of England and Wales will remain mild and wet as we head into the Easter Weekend IMO.

Edited March 24, 2018 by Nick F

[SMU]

For me there lies an opportunity of snow across the UK late weds as the front spreads & clears south being undercut by colder air....

[SMU]

Note for the first time the 06z IKON produces some more significant cold air from the East-

[Summer Sun]

GFS 06z shows only Scotland most prone to the coldest air over Easter

[mb018538]

As that low pressure system just sits and fills over the UK, there is going to be a fair amount of ppn the next 10 days, with no areas really immune:



Shouldn't be anything to cause alarm, just a typical wetter spell of weather.

[Summer Sun]

A quick reminder to all more so the newer members tomorrow sees the UK spring forward into British summer time this means all models from 00z tomorrow (Sunday 25th) will be 1 hour later in updating

Approx times for the main models

GFS

00Z 0430-0545

06Z 1030-1145

12Z 1630-1745

18Z 2230-2345

ECM

00Z 0700-0800

12Z 1900-2000

UKMO (Updates usually complete within 30 minutes)

00Z 0500

12Z 1700

[Summer Sun]

The snow row on the GFS ens for the south shows the chances fading now

London

Cardiff

Brighton

The snow row is a bit higher at times further north but if you want Easter snow the best chance for the northern cities looks to be Inverness

Edinburgh

Inverness

Newcastle

[johnholmes]

3 hours ago, Nick F said:

General agreement on an upper vortex splitting from tropospheric PV over N Canada and moving SE with a collocated surface low pressure system towards NW Iberia during the week, but when it gets to SW of the UK, differences on how far north or south the upper/surface low will be - which impacts how far south the cold air being pulled west out of Scandinavia gets.

GFS and UKMO further with north the low and cold end of the week compared to EC, so GFS is showing snow confined to Scotland and perhaps higher parts of N Wales and N England. EC on the other hand has snow event as far south as Wales and Midlands next Friday night / early Saturday.

Until post day 6 position of the upper/surface low out west is firmed up on, then difficult to know where is in the frame for potential snowfall from mid-week next week. Though northern areas most favoured and good chance southern areas of England and Wales will remain mild and wet as we head into the Easter Weekend IMO.

Yes a tricky one Nick.

The anomaly charts suggest a quite large upper vortex/trough w of the meridian and south of the UK. Not conslusive and some differences between the main 3, see below, and to some extent with one another over the past 2-3 days.

The overall outlook to ne would suggest that they will be far enough south for Scotland to be pulled into the fairly deep cold air but south of the Border then some kind of change-over north of a , guess really, line from say Blackpool to Whitby, with relatively mild air south of this line?

links

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[Summer Sun]

00z NASA shows the south seeing the best of the temperatures over the Easter weekend with the north always that bit cooler/colder

[bluearmy]

ICON back to its 00z less chilly theme 

[Summer Sun]

12z ICON isn't following the 06z in pulling the coldest air more widely over the UK

12z left 06z right

Looks closer to the 00z to me

 

Edited March 24, 2018 by Summer Sun

[feb1991blizzard]

That's it then - game over - UKMO - no snow, GFS - no snow, ICON - no snow.

EDIT : Actually UKMO 120 isn't too bad.

Edited March 24, 2018 by feb1991blizzard

[Daniel*]

1 minute ago, feb1991blizzard said:

That's it then - game over - UKMO - no snow, GFS - no snow, ICON - no snow.

I don’t know this seems a pretty decent chart from UKMO. It does appear models have backed off anything overly cold as the month wraps up however first week of April better potential I’d say.

[feb1991blizzard]

Just now, Daniel* said:

I don’t know this seems a pretty decent chart from UKMO. It does appear models have backed off anything overly cold as the month wraps up however first week of April better potential I’d say.

 

1 minute ago, Daniel* said:

I don’t know this seems a pretty decent chart from UKMO. It does appear models have backed off anything overly cold as the month wraps up however first week of April better potential I’d say.

That's the 0z but I agree the 12z 120 UKMO isn't as bad as some models.

[bluearmy]

Ukmo would be snowy n midlands northwards in winter but going to need decent elevation back end March 

[Frosty.]

2 minutes ago, feb1991blizzard said:

 

That's the 0z but I agree the 12z 120 UKMO isn't as bad as some models.

Just being honest here, the week ahead does look more wet than white with temps actually pretty decent further south on the Gfs 12z.

[Daniel*]

2 minutes ago, feb1991blizzard said:

 

That's the 0z but I agree the 12z 120 UKMO isn't as bad as some models.

Oh not so on it following family wedding yesterday. UKMO is certainly horrific if you want spring like weather. With potential for greater interest, the models have really not got anywhere it seems. 

[Leon1]

just my eyes or is the LP on the 12z further west?

[bluearmy]

Gem and gfs doing their best for coldies but it looks quite an uphill slog away from the jocks !! 

[Leon1]

6z:     12z:          Big improvements but not quite there yet!

[Summer Sun]

Nothing overly cold on UKMO 12z taking us to Good Friday

 

[Frosty.]

3 minutes ago, Summer Sun said:

Nothing overly cold on UKMO 12z taking us to Good Friday

 

Yes you're right Gavin, although you're showing charts that coldies don't want to see, you're posts are always fair and balanced with no ramping.

[The PIT]

If you want Winter it's case of go to Scotland. Apart from some frost nothing wintry away from there this week.

[Frosty.]

4 minutes ago, The PIT said:

 Apart from some frost nothing wintry away from there this week.

You mean next week, and actually it doesn't even look that wintry across scotland, nothing compared to previous wintry episodes anyway!

[Northern Sky]

5 minutes ago, The PIT said:

If you want Winter it's case of go to Scotland. Apart from some frost nothing wintry away from there this week.

Good we're three weeks into Spring! It's been a very good Winter but I've really had enough of cold now. I want to get in the garden and feel some sunshine and warmth. Unfortunately not much of that on show in the models either  - until 360hrs anyway