Model Output Discussion - Christmas and New Year

[ALL ABOARD]

3 minutes ago, Allseasons-si said:

Yep sorry,i did download the latest but it came up with that,strange

here it is from the 24th.

 

Some extreme reversals on there getting towards - 30m/s 

Also the mean seems to be dropping below the - 5 mark. 

 

[Kasim Awan]

3 minutes ago, markw2680 said:

I’d actually be quite surprised if it went that far north east come the time of it but you never know

Yeah I've changed my mind now lol, these things are tricky

I will refrain from posting these in here again as I feel it isn't suited well to "model output".

Edited December 26, 2020 by Kasim Awan

[Allseasons-Si]

Latest ICON's take on the snow 08:00 Monday morning

i will update further in a bit.

[sheikhy]

Jeeeez!!gives 10cms for the midlands!!im just gona laugh at that!!

[sheikhy]

Scrap what i said above!!it gives 15cms

[Kasim Awan]

Confidence is vv high now yes I think somewhere in the midlands will get over 10cm

[Scott Ingham]

Just now, Kasim Awan said:

Confidence is vv high now yes I think somewhere in the midlands will get over 10cm

My locale in South Yorkshire also in the firing line now! Unbelievable we had nothing forecast yesterday at all it was all too far south!

[Allseasons-Si]

In motion,it looks like pivoting into the midlands,i will have more when the run finishes.

[Mike Poole]

Just getting settled into a long post, on the go, first like to remind people of a previous Boxing Day:

Yes, gratuitous ‘62 chart, but there hadn’t been much in terms of winter before that but in those bygone days, and the trop vortex was largely banished from its usual home (as it is right now).  

Looking at the models (excessively so this year with lockdown boredom) I tend to pick up on an underlying vibe.  Think spring 2018.  I was looking at the model output thinking I haven’t seen this before.  There was something unusual about the jet stream, and I made predictions about it on here.  And a summer to rival 1976 followed (although not with the drought issues). 

This winter the charts are looking different to usual fayre too.  Gone is the jet straight across the Atlantic, replaced by a meandering meridional jet that waxes and wanes, here it is right now:

I have seen this in early winter only to get steamrollered as usual by the strat vortex.  But that hasn’t happened this year.  Not at all.  It is different.  And different is good.  

We are starting to experience the colder weather now with the current pattern, which I expect to wax and wane for a while, but we are also heading into January, short days, and colder sea temperatures.  And we are expecting a SSW.  It could be as early as this and look like this:

If it does look like this, most runs that show a split look like this (and some models are not in agreement yet), then there is the potential for the cold spell just starting to develop into something more potent into the heart of winter.  

Nothing like ‘63 is going to happen, we are in a warmer world now.  But something out of the ordinary is about to happen in my view, the model charts are just too unusual to ignore...

 

 

 

[sheikhy]

My god that latest ukv looks similar to icon!!is the midlands back in it last minute!!

[Tim Bland]

Here is the icon snow depth...

[markw2680]

3 minutes ago, sheikhy said:

Scrap what i said above!!it gives 15cms

Sounds more like it!!

tbh I’d be happy with an inch,

let’s just hope the models firm up on the cold coming during the week and brings us all some decent surprises 

[Stu_London]

3 minutes ago, Steve Murr said:

In terms of south of M4 > Elevation & intensity the key.

For me if the PPN is heavy enough you could drive at the base of the downs in sleet & 2c & have snow & 0c up at west Kingsdown -

Sleety mess for most in the south east. Downs might get a covering

[Kasim Awan]

1 minute ago, Steve Murr said:

In terms of south of M4 > Elevation & intensity the key.

For me if the PPN is heavy enough you could drive at the base of the downs in sleet & 2c & have snow & 0c up at west Kingsdown -

Agree North of M4 will be all snow if this occurs at the time it is currently modelled. Confidence now >60% too so warnings should be issued soon. 

[Scott Ingham]

1 minute ago, Kasim Awan said:

Agree North of M4 will be all snow if this occurs at the time it is currently modelled. Confidence now >60% too so warnings should be issued soon. 

Whats your opinions of South Yorkshire?

[Guest]

3 minutes ago, Tim Bland said:

Here is the icon snow depth...

I'll admit the ICON is a dream come true with regards to snow potential up here in South Yorks. NMM has something similar but ARPEGE takes the system much further south, so I agree with other posters that this'll likely be a nowcast scenario.

 

[Kasim Awan]

6 minutes ago, Scott Ingham said:

My locale in South Yorkshire also in the firing line now! Unbelievable we had nothing forecast yesterday at all it was all too far south!

It was always within scope as ecm hinted a more northerly track earlier. Wherever this pivots is getting their snow weight in a 1:10 ratio. Pennines 1:12 so you can see why I'm thinking highly for Peaks atm.

I feel slight southwards corrections are possible only 50-70miles. Again v slim chance this corrects south 

[sheikhy]

1 minute ago, Kasim Awan said:

It was always within scope as ecm hinted a more northerly track earlier. Wherever this pivots is getting their snow weight in a 1:10 ratio. Pennines 1:12 so you can see why I'm thinking highly for Peaks atm.

I feel slight southwards corrections are possible only 50-70miles. Again v slim chance this corrects south 

Lets see where gfs goes!!doubt it will look like the icon but lets see!!

[markw2680]

I do think there will be movements of about 50-100 miles yet east or west and where it pivots could well be in for quite a bit, just my view , it won’t be nailed completely even this time tomorrow so expect the unexpected 

[Scott Ingham]

1 minute ago, Kasim Awan said:

It was always within scope as ecm hinted a more northerly track earlier. Wherever this pivots is getting their snow weight in a 1:10 ratio. Pennines 1:12 so you can see why I'm thinking highly for Peaks atm.

I feel slight southwards corrections are possible only 50-70miles. Again v slim chance this corrects south 

Not fully sure of the amount for me based on altitude of 70 metres east of the pennines  but we will see! Trending right for me at this second but still time for change

[A Frayed Knot]

Wales in the game for defo

[Stu_London]

Just now, Mr Brown said:

I’m guessing London will miss out on this one...

I would say you are guessing right. But you never know, its a very fluid situation. 

London tends to fare better with winds in the easterly quadrant, so perhaps one or two surprises a bit further down the line.

[The Enforcer]

15 minutes ago, Allseasons-si said:

Latest ICON's take on the snow 08:00 Monday morning

i will update further in a bit.

I agree this is going to move about all over the place and will still be doing so at T+6. I notice it's put down an early marker with a solitary blob of rain encircled by snow:

[Mike Poole]

For snow potential, the ICON-EU is similar in some ways but not others to the 12z EURO4:

ICON is much further to the S and E.  Probably be able to get a better handle on this tomorrow, when we should have all the short range models within range.

 

[SMU]

2 minutes ago, Kasim Awan said:

It was always within scope as ecm hinted a more northerly track earlier. Wherever this pivots is getting their snow weight in a 1:10 ratio. Pennines 1:12 so you can see why I'm thinking highly for Peaks atm.

I feel slight southwards corrections are possible only 50-70miles. Again v slim chance this corrects south 

It would be nice to have some QPF forecasts for the Uk...  & some basic SLRs