Model output discussion - deep cold inbound?

[Don]

3 minutes ago, Kreftysoton said:

Sounds about right! Southampton has a grey gap with no measurement lol

Yes, there often seems to be that sort of gap for Southampton with snow forecasts!  I'm not a million miles away but am almost in the sweet spot on that chart!  However, lots of twists and turns to come over the next 7 days!

[Paul]

3 minutes ago, Don said:

Yes, there often seems to be that sort of gap for Southampton with snow forecasts!  I'm not a million miles away but am almost in the sweet spot on that chart!  However, lots of twists and turns to come over the next 7 days!

It's because of the relative low resolution of the GFS, some coastal areas have their grid squares mostly in the sea, so as snow doesn't tend to like settling on the sea, that's why the Southampton area, parts of East Kent and other coastal towns are often shown as snowless on it. The problem also affects its surface and 2m temperature forecasts, for the same reason.

[Day_9]

6 minutes ago, chris pawsey said:

Can I ask, when do people consider FI to be now? 

5 days

[MAF]

18 minutes ago, Paul said:

It's because of the relative low resolution of the GFS, some coastal areas have their grid squares mostly in the sea, so as snow doesn't tend to like settling on the sea, that's why the Southampton area, parts of East Kent and other coastal towns are often shown as snowless on it. The problem also affects its surface and 2m temperature forecasts, for the same reason.

so @Paul what's your'e take on current synopsis, if i may ask.

you are always very level headed when it comes to these situations so an unbiased forecast from you may help other posters see where they stand  

obviously, i ask this on your interpretation of current modelling and understand it may differ to other opinions

[kold weather]

30 minutes ago, Don said:

Yes, there often seems to be that sort of gap for Southampton with snow forecasts!  I'm not a million miles away but am almost in the sweet spot on that chart!  However, lots of twists and turns to come over the next 7 days!

My best guess is the global models struggle with the shape of the solent, and because of the grid sizes they have they will go for a lower average as a way of accounting for the odd shape of the solent? 

Or perhaps its a real signal, but I can't see any real logical reason given the wind direction is overland other than the grid point solution mentioned above.

EDIT - haha Paul got there first, pleased to see that my guess was right though!

Edited February 4, 2021 by kold weather

[Kreftysoton]

1 minute ago, kold weather said:

My best guess is the global models struggle with the shape of the solent, and because of the grid sizes they have they will go for a lower average as a way of accounting for the odd shape of the solent? 

Or perhaps its a real signal, but I can't see any real logical reason given the wind direction is overland other than the grid point solution mentioned above.

Thanks for the input and totally agree any onshore winds and its game over before its even started for us. We need winds of the land to get snow here at sea level. Fingers crossed we get to see a few flakes havent seen a flake since Mar 2018

[ICE COLD]

The ICON 12z is not updating boo 

[NewEra21]

5 minutes ago, ICE COLD said:

The ICON 12z is not updating boo 

I guess it's froze, quite literally

[sheikhy]

7 minutes ago, ICE COLD said:

The ICON 12z is not updating boo 

Phew!!i thought the easterly had vanished!!!!ah well over to the gfs first!!even better!!

[weirpig]

arperge  take on snowfall

[Don]

1 minute ago, sheikhy said:

Phew!!i thought the easterly had vanished!!!!ah well over to the gfs first!!even better!!

Lol, if that was to happen at this late stage I think many on here (myself included) would give up looking for cold in future!

[NewEra21]

2 minutes ago, Don said:

Lol, if that was to happen at this late stage I think many on here (myself included) would give up looking for cold in future!

In our heart of hearts we all know it can still happen though, I guess that's why we're all still here until we finally get this cold over the line. All part of the fun and torture I guess

[Battleground Snow]

6 minutes ago, weirpig said:

arperge  take on snowfall

Doesn' look as impressive as the other models but a big improvement on its 00z run

Edited February 4, 2021 by Battleground Snow

[weirpig]

1 minute ago, Battleground Snow said:

Doesn' look as impressive as the other models but a big improvement in its 00z run

Yep  for me its probably the most realistic    most of the snow will come from streamers  imo   and that wont be decided to way closer to the time.

[kold weather]

1 minute ago, Battleground Snow said:

Doesn' look as impressive as the other models but a big improvement in its 00z run

Yrah I suspect the models will steadily increase the precipitation amounts over the next day or two.

That is typically how these types of things evolve, though it often also brings the risk of milder air circulating as well as we move into the timeframe.

I will probably gladly take that if it came off, even if it is a little more modest than most other runs.

[swebby]

2 hours ago, georgiedre said:

Very warm on West Coast of Wales lol. Wtf is that about 

Looks like a Foehn effect from the Easterly?

Foehn effect

WWW.METOFFICE.GOV.UK

---

The foehn effect causes warming and drying of air on the lee side of cross mountain wind.

 

[Ice Day]

The Icon is now rolling on Meteociel 

[Battleground Snow]

1 minute ago, kold weather said:

Yrah I suspect the models will steadily increase the precipitation amounts over the next day or two.

That is typically how these types of things evolve, though it often also brings the risk of milder air circulating as well as we move into the timeframe.

I will probably gladly take that if it came off, even if it is a little more modest than most other runs.

True, I always find arpege a bit erratic until it gets to within 48 hours out, I can't wait to see arome when that gets in range

[ICE COLD]

12z arpege looking good on uppers at T81

[Midlander]

A nice depiction of one or two streamers there, will undoubtedly change locations in subsequent runs but helps explain the snowfall total above.

[ICE COLD]

3 minutes ago, Ice Day said:

The Icon is now rolling on Meteociel 

Omg it’s gonna be carnage with both ICON and GFS rolling at the same time . 
 

 

[TSNWK]

4 minutes ago, ICE COLD said:

12z arpege looking good on uppers at T81

Like that.. less cold sector well clear over Holland

[TSNWK]

2 minutes ago, ICE COLD said:

Omg it’s gonna be carnage with both ICON and GFS rolling at the same time . 
 

 

Don't forget UKM and the parr

[craigore]

4 minutes ago, AppleUK 123 said:

A nice depiction of one or two streamers there, will undoubtedly change locations in subsequent runs but helps explain the snowfall total above.

Whys it showing rain in East Kent.

Surely the uppers are more than cold enough to produce snow by then even in coastal areas.. 

[Badgers01]

1 minute ago, craigore said:

Whys it showing rain in East Kent.

Surely the uppers are more than cold enough to produce snow by then even in coastal areas.. 

unfortunately there is a persistent trend to show less cold uppers across varying parts of the South east  - hopefully this will correct soon but it’s not 100 per cent snow sure everywhere !!