FI Charts (T120+ onwards) Winter 2018 **READ MOD NOTE IN FIRST POST**

snowstorm445

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!

M.T. Cranium

My comment had nothing to do with understanding retrogression, I just don't think there's going to be a large-scale northerly that soon into the event, and I don't think the east-west high pressure ridge would suffer that much disruption, but it's just an opinion, I have no basis for disputing it other than it looks low probability even if you totally buy into the set-up which itself is a test of our faith (one that very few seem to have failed in the past 24 hours).

Elmer Blooker

Mullaghteelin wrote: »

It doesn't disappear, it retrogressing westward.

The stratospheric warming has put everything in reverse, so the high moves westward over time.

The northerly about to hit us on the ECM is very potent in its own right, so its all good.
We should see further cold plunges from the north or northeast, as long as the block doesnt go any further west than Greenland.
But lets get the easterly out of the way first

Unfortunately thats what appears to be happening, the block is almost as far west as Hudsons Bay and no blocking worth talking about to the north east and the easterly is cut off.
Becoming milder from the south. The Golden Rule: whatever can go wrong ...

dacogawa

GFS seems to have backed off or slowed down a bit on this run so far...

Rebelbrowser

Looks to me as though GFS and ECM have converged. Monday is the day it seems.

pad199207

dacogawa wrote: »

GFS seems to have backed off or slowed down a bit on this run so far...

Yep cold looks delayed a bit on this run, its as you were though from then on.

That is a serious cold pool building to our east on this run!

dacogawa

Slowed but came back with a bang -12 850 from Scotland to Northern France to Cork, really amazing chart watch at the moment.

pad199207

I think this is another upgrade bloody hell!

Rebelbrowser

Cold pool much bigger. Slight delay but ECM and GFS now off exact same hymn sheet at 5.5 days out. Chart for Wednesday next week shows the cold pool but the cold in earnest arrives overnight on Sunday / Monday

George Sunsnow

Remember the finger of green or yellow usually seen in these spells up through Britain and Ireland?
I’ve found it
That’s the Canadian coast immediately to its left btw

Edit Grrrrr 1Mb file size limit so no attachment :mad:

But as regards where the mild finger is gone

Cantona's Collars

George Sunsnow wrote: »

Remember the finger of green or yellow usually seen in these spells up through Britain and Ireland?
I’ve found it
That’s the Canadian coast immediately to its left btw

Edit Grrrrr 1Mb file size limit so no attachment :mad:

But as regards where the mild finger is gone

Can you upload the images to a hosting site and post the link? It might solve the problems of file size.

Donegal Storm

George Sunsnow wrote: »

Remember the finger of green or yellow usually seen in these spells up through Britain and Ireland?
I’ve found it
That’s the Canadian coast immediately to its left btw

Edit Grrrrr 1Mb file size limit so no attachment :mad:

But as regards where the mild finger is gone

imgbb.com does the trick, just upload the image there then copy the link they give you

pad199207

Towards the end of the run, its just relentless. All a bit mad really!

gabeeg

GFS brings a second blast from the East a week after the initial one.

This would be a bit too much

lucernarian

This one has me a little nervy. It's only slightly synoptically different from the others but we're lacking the lower pressure and unstable flow that 2010 had. I've seen snow trains going at 1020 and 1025 hPa but hitting 1035 hPa would leave us with bitter cold and not much else.

Thoughts?

Reckless Abandonment

lucernarian wrote: »

This one has me a little nervy. It's only slightly synoptically different from the others but we're lacking the lower pressure and unstable flow that 2010 had. I've seen snow trains going at 1020 and 1025 hPa but hitting 1035 hPa would leave us with bitter cold and not much else.

Thoughts?

Dublin had rain pop up a few weeks back with presure over 1035
Pressure drops off a little later that Monday as well, looks very snowy for the rest of the week.

lucernarian

Reckless Abandonment wrote: »

Dublin had rain pop up a few weeks back with presure over 1035
Pressure drops off a little later that Monday as well, looks very snowy for the rest of the week.

Isn't that the exception that proves the norm? I still expect it to snow as things stand, but the pressure makes much of the difference between snizzle and thundersnow.

Could anyone give an insight into what sort of signals we should be looking for to track the evolution of the high (and whether it'll be further north or south than currently progged)? 2010 started out as a different kind of beast and with the Greenland High being so strong back then, nothing could have gone wrong barring the fickle sea-effect snow.

KingdomRushed

lucernarian wrote: »

This one has me a little nervy. It's only slightly synoptically different from the others but we're lacking the lower pressure and unstable flow that 2010 had. I've seen snow trains going at 1020 and 1025 hPa but hitting 1035 hPa would leave us with bitter cold and not much else.

Thoughts?

The chart shown is for Monday, the pressure is dropping at that stage across all models. The real thickness is coming soon after.

lucernarian

If the high doesn't sink over us :pac:

Rebelbrowser

One more model test passed. See Icon (I know) below...

gabeeg

Yep, and the GFS looks to be on track too

Rebelbrowser

And UKMO good!

Villain

GFS 12z delays it a little but still looks good!

Rebelbrowser

Villain wrote: »

GFS 12z delays it a little but still looks good!

Yup. All the models now agree the cold air hits us during Monday. Model agreement is very encouraging (and what you'd expect at this range too for any other weather event)

MJohnston

ARPEGE 12Z is disappointingly disagreeable, only it and the GEM not onboard:

http://www.meteociel.fr/cartes_obs/comp_panel.php?mode=1&ech=114&size=0

nacho libre

. Wrong thread.

dacogawa

Not bad for lunchtime Monday from the ECM run

dacogawa

That will do!

Darwin

Idea stolen shamelessly from netweather...the beast from the east cometh:

sdanseo

MJohnston wrote: »

ARPEGE 12Z is disappointingly disagreeable, only it and the GEM not onboard:

http://www.meteociel.fr/cartes_obs/comp_panel.php?mode=1&ech=114&size=0

The 0Z GEM was on board to an extent and both it and the 12Z show the cold mass behind so more of a delay than a downgrade.

ARPEGE only goes to +114 and shows 7am Sunday -2 uppers in the North Sea with much deeper cold behind (click on Allemagne/Germany to see further east).