Model Output Discussion - Christmas and New Year

[swfc]

Morning the oz gfs takes another swing on the nhp at the190 hr mark. Such a huge change not sure how accurate compared to the 18z. Just to note quite a cold flow included in the low over the UK giving snow at ten days plus all academic at the said timescale

Edited December 26, 2020 by swfc

[Dave Kightley]

5 minutes ago, swfc said:

Not sure if this run is or ties in with a less warmer run at 10hpa. That said sits in the group bluearmy alluded to ie greenland Heighths previous

Hinting at Height rises over Scandinavia as well.. completely blocked everywhere... I think it has been hinting at sliders for a few days rather then a beast right now.. sliders with abit if heights over Scandinavia area might help keep the slide further west if that is a good thing  or not I'm not sure

Edited December 26, 2020 by Dave Kightley

[That ECM]

6 hours ago, Allseasons-si said:

The short gefs ens for my local and London look cold no doubt after the boxing day blip.

I appreciate these 850’s are not on the back of the run I am showing at T216 but it does illustrate my thinking. The first part is relatively easy the second is very difficult.

You will see a multitude of different outcomes, some dry some not. Some with the ridge having a greater influence and some not. So calling the weather as things change and pop up is very hard. However if you look at the 850’s they are in the most part similar. -4, -5 and on occasions-6. 
 

so predicting that it is going to be cool/cold isn’t hard. Predicting the actual weather type is.

Edited December 26, 2020 by That ECM

[swfc]

21 minutes ago, Dave Kightley said:

Hinting at Height rises over Scandinavia as well.. completely blocked everywhere... I think it has been hinting at sliders for a few days rather then a beast right now.. sliders with abit if heights over Scandinavia area might help keep the slide further west if that is a good thing  or not I'm not sure

Yes things very fluid atm. The atmosphere is playing with various options none landing at a mild conclusion. 

Edited December 26, 2020 by swfc

[swfc]

4 minutes ago, That ECM said:

I appreciate these 850’s are not on the back of the run I am showing at T216 but it does illustrate my thinking. The first part is relatively easy the second is very difficult.

You will see a multitude of different outcomes, some dry some not. Some with the ridge having a greater influence and some not. So calling the weather as things change and pop up is very hard. However if you look at the 850’s they are in the most part similar. -4, -5 and on occasions-6. 
 

so predicting that it is going to be cool/cold is isn’t hard. Predicting the actual weather type is.

Good points. If I was a betting man I'd expect some more subtle changes on the oz ec also. Very complex nhp and also intriguing. 

[Dave Kightley]

UKMO has some really good uppers like a day or after the 144 chart but pretty pathetic before that really and not sure what will happen afterwards heights wise..

[swfc]

4 minutes ago, Dave Kightley said:

UKMO has some really good uppers like a day or after the 144 chart but pretty pathetic before that really and not sure what will happen afterwards heights wise..

I'd suspect the Heighths on the ukmo would interact with the Heighths existing the esb USA. Temps ete are all up for grabs but atm on the nhp nothing exceptional really

Edited December 26, 2020 by swfc

[swfc]

Gfs oz control follows the op in regard to a greenland high be it fi. The ec will be interesting later but probably none the wiser at day 6-10

Edited December 26, 2020 by swfc

[northwestsnow]

GEM is an absolute beauty of a run...

Nothing like ukmo at 144 however...

[Tim Bland]

15 minutes ago, northwestsnow said:

GEM is an absolute beauty of a run...

Nothing like ukmo at 144 however...

Love it! Check out those snow totals at day 10 everyone gets a covering even some decent amount right on the south coast...

[Jayfromcardiff]

What's everyone's thoughts on the position of that low on Monday? To me it looks like anywhere from South Wales across to Kent could see some snow.

[swfc]

7 minutes ago, Jayfromcardiff said:

What's everyone's thoughts on the position of that low on Monday? To me it looks like anywhere from South Wales across to Kent could see some snow.

Latest update is far southern area/coast ete

[tight isobar]

Just now, Tim Bland said:

Love it! Check out those snow totals at day 10 everyone gets a covering even some decent amount right on the south coast...

 

6 minutes ago, Jayfromcardiff said:

What's everyone's thoughts on the position of that low on Monday? To me it looks like anywhere from South Wales across to Kent could see some snow.

Allude to

 

Just now, swfc said:

Latest update is far southern area/coast ete

Most certainly..the western direct some are mentioned is way off the track mark.. it’s a diagonal track.. south eastern exit point.. and there is where the exactions will be correct for precipitation =snow.

[Weather-history]

1 hour ago, swfc said:

Not sure if this run is or ties in with a less warmer run at 10hpa. 

That implies what happens at 10hpa level has an immediate impact and just isnt the case

[Ali1977]

Big differences with the Atlantic WAA at 144 this morning between GFS and ECM, FI is pretty early at the minute and I’d be surprised if these ‘less cold’ charts on the GFS’s FI materialise . 

[Jayfromcardiff]

2 minutes ago, tight isobar said:

 

Allude to

 

Most certainly..the western direct some are mentioned is way off the track mark.. it’s a diagonal track.. south eastern exit point.. and there is where the exactions will be correct for precipitation =snow.

So are you saying this is looking like mainly snow for the SE? It seems hard to pin down this low pressure as it's constantly moving on every run.

[tight isobar]

9 minutes ago, Jayfromcardiff said:

So are you saying this is looking like mainly snow for the SE? It seems hard to pin down this low pressure as it's constantly moving on every run.

It is @hard deciphering.. yet it’s a classic set up of transitions of mild to cool/colder of a main at first pm airflow.. isobar/feed tracing always takes these transitions system south east.. and the roulette wheel will likely fall on any precipitation conversion in/around south eastern quads!! Seen/>been under it many times.. we’ll see be interested to see where/how this goes.. but that is my definition/assumption-expectations

Edited December 26, 2020 by tight isobar

[tight isobar]

11 minutes ago, Jayfromcardiff said:

So are you saying this is looking like mainly snow for the SE? It seems hard to pin down this low pressure as it's constantly moving on every run.

View this morns ecm ooz in the uk out -chart.. it’s raw out performance is preety good @around 48hrs out.. it WILL speak volumes this morning!

Edited December 26, 2020 by tight isobar

[Tim Bland]

ECM was the best output in terms of snow on Monday and now even that doesn’t have much. There’s a trace (1-2cn) in the south east and some for the hills of Wales and north west. Apart from that ( believe it or not ) Monday is a mainly dry day for most. Hopefully when the high res models like Euro4 come into range later we will see more in the way of convective activity, but most of the precip from the low ends up in the Irish Sea and off the coast off the south west before pivoting through the channel. Snow shown on the chart below  is mainly from the wrap around casing some showers to come don through the wash. This is only the starter though..plenty more opportunities to look at over the next week or so...

[That ECM]

Fun for some.

[Jayfromcardiff]

5 minutes ago, Tim Bland said:

ECM was the best output in terms of snow on Monday and now even that doesn’t have much. There’s a trace (1-2cn) in the south east and some for the hills of Wales and north west. Apart from that ( believe it or not ) Monday is a mainly dry day for most. Hopefully when the high res models like Euro4 come into range later we will see more in the way of convective activity, but most of the precip from the low ends up in the Irish Sea and off the coast off the south west before pivoting through the channel. Snow shown on the chart below  is mainly from the wrap around casing some showers to come don through the wash. This is only the starter though..plenty more opportunities to look at over the next week or so...

This is why I never get my hopes up with snow, especially as it's so unpredictable.

[That ECM]

1 minute ago, Jayfromcardiff said:

This is why I never get my hopes up with snow, especially as it's so unpredictable.

This why I never get to despondent with snow, especially as it’s so unpredictable.

[tight isobar]

Variations on the theme.. a great ec-00z and those heights/gains @greenland no worries.. the ridge is steadfast ..and underplayed this far out imo.. and if it isn’t... I’ll take it as it’s moddeled... another banger of a start.!!@draw =extract..

Edited December 26, 2020 by tight isobar

[Tim Bland]

13 minutes ago, That ECM said:

Fun for some.

Still looks mainly dry though I know the saying ‘get the cold and the snow will follow) but we are fairly certain the cold is coming now , so the focus is on snow for me. ECM is a very dry run with little precip for anyone. Once the cold is in I’ll be looking at the high res runs for any features in the flow as I expect (hope)  these low res runs are just missing them?!

Edited December 26, 2020 by Tim Bland

[KTtom]

Certainly looks a dryer run from ECM and GFS away from the east coast, what is stark is how many attempts the Atlantic ridge makes at getting into Greenland, ECM day 9 shows it smacking into a concrete wall and flattening! The biggest stumbling block IMO to getting something more notable is shifting that lobe of vortex from Greenland. Still, looking at least 10 days of cold frosty conditions once the storm clears which is not to be sniffed at.