Model Output Discussion 01/09/17

[feb1991blizzard]

2 minutes ago, snowbunting said:

Its the heights over Greenland that are truelly astonishing. Promising lots of Nly outbreaks. One of these is going to create fun and games. 

like that chart you posted, it promises a N'ly but ends up delivering a powerhouse westerly even with those stonking heights.

[Dean E]

3 minutes ago, feb1991blizzard said:

like that chart you posted, it promises a N'ly but ends up delivering a powerhouse westerly even with those stonking heights.

That would be one rather cold Westerly... Shift it East by a few Hundred miles and it is a totally different outcome.

 

Edited November 25, 2017 by Dean E

[feb1991blizzard]

1 minute ago, Dean E said:

That would be one rather cold Westerly... Shift it East by a few Hundred miles and it is a totally different outcome.

 

Yes its a North-Westerly!!!!

[Nick F]

6 minutes ago, snowbunting said:

Its the heights over Greenland that are truelly astonishing. Promising lots of Nly outbreaks. One of these is going to create fun and games. 

That’s a sea level pressure chart, rather than heights, often the pressure seems extremely high over Greenland, but this is this the model trying to calculate the pressure over the high plateau covered in ice that dominates Greenland rather than representative of sea level pressure. 

Chart below shows similarly high pressure at the surface over Greenland, while above are low heights (blue) indicative of upper troughing.

[Frosty.]

The GFS 18z is a very interesting run, even after next week's arctic outbreak there is some further cold very unsettled spells with a mix of rain, sleet and snow, the snow especially further north and on high ground but it's certainly not a boring stagnant pattern..anyway, I'm now  focussed on quite a wintry feeling spell after monday..looking forward to it. 

[feb1991blizzard]

The GEFS are the worst suite for a while, cant get low Euro heights at all.

[karlos1983]

seen a lot worse 

Edited November 25, 2017 by karlos1983

[nick sussex]

I'd be a bit wary of the outputs at the moment as they seem to be caught between two evolutions.

At this point I'd prefer an easterly or ne as that's possible given our starting point. My reservations re retrogression is whether we'll end up with the block too far west which happened last week. One wasted block is enough in two weeks, a second would be an insult to coldies in here!

 

[kumquat]

I see this year on year about the pressure/temp measurements on the Greenland plateau. Surely not that difficult to fix by adding new data gathering points in this part of the world? Or is it just a myth rolled out every time? If it's a depth through the FEA that is the problem then a localised fix could be used.

[blizzard81]

1 hour ago, bluearmy said:

It has been a west based neg nao - we just had a week of dropping NAO down to -3 and it corresponded to almost record mild temps in e England! 

But it was originally forecast to stay west based. In reality, we only had to endure 48 hours of it. I can live with that. The point I am making is don't be surprised if the the models overestimate the west based element again in the near future. 

[Daniel*]

Steve M spoke of GFS bias to underestimate the depth of low heights of the Euro low.

Likewise too this may have come to light with UKMO with this characteristic, EC is king. Compare 00z to 12z of yesterday - a fair bit better, cleaner upstream, cold surface conditions.

w

Edited November 26, 2017 by Daniel*

[knocker]

I'm feeling rough with the dreaded luigi this morning so brief is the word.

Currently we still have the low adjacent to south west Norway so the UK still in a cold north westerly, with an icy start in many places , so wintry showers will continue albeit mainly in the north but tending to be less frequent before dying out. The reason for that is later in the day a wave depression and associated fronts will approach from the north west bringing cloud and rain to the W/NW, perhaps some brief snow in the highlands, which will track south over night and tomorrow, Behind the front the wind will veer heralding the introduction of colder air and the expected new regime.

So by midday Tuesday the low has slipped south east into the Baltic States whilst the high pressure to the west surges north into Iceland thus the UK in a northerly airflow.with wintry showers in the north and down the east coast. Over the next 48 hours the high pressure ridges north east forcing the low south west over Holland and northern Germany which veers the wind north east over the UK which will tend to concentrate the wintry showers along the east coast. The notable feature of the week is that it will be cold with widespread airfrosts in the mornings

.

But there is good news on the horizon  The colder air gets shunted south and east as the high pressure takes closer order and the energy running around the top slips a front south accompanied by rain and somewhat warmer air during Friday.

Over the weekend the high comes under pressure from energy tracking east to the north west but manages to maintain a ridge into the UK so a dry weekend albeit still the chance of frost in the mornings.

So in summation I think one can safely say a pretty cold week with some wintry precipitation around but probably mostly confined to the higher ground and coastal areas with elsewhere remaining pretty dry and little sign of any sustained cold spell albeit temps liable to remain a tad below average.

 

[Dennis]

winter king at the gate 

[Dennis]

EC 0z ....reload after 3 dec 

Edited November 26, 2017 by Dennis

[northwestsnow]

Im liking the look of EC at 168 :-)

[northwestsnow]

8 minutes ago, Dennis said:

EC 0z ....reload after 3 dec 

Is the euro low going to be our saviour here ? 

[ICE COLD]

Is the high gonna keep heading for Greenland Ec 192hrs . 

[Dennis]

3 minutes ago, northwestsnow said:

Is the euro low going to be our saviour here ? 

yes too but also the LOW pressure in NE US ; and the RELOAD

Edited November 26, 2017 by Dennis

[ICE COLD]

Back in the game  . ECM 216 Hrs . Cold air spreading south . 

Edited November 26, 2017 by ICE COLD

[knocker]

All things considered the ecm quite close to the gfs with cold air shunted south next weekend as the ridge comes under pressure from a strong jet running across the south of Greenland and south of Iceland.

"The hills are alive to the sound of music".

Edited November 26, 2017 by knocker

[Dennis]

its a start  December could bring the winter more and more

Edited November 26, 2017 by Dennis

[northwestsnow]

9 minutes ago, knocker said:

All things considered the ecm quite close to the gfs with cold air shunted south next weekend as the ridge comes under pressure from a strong jet running across the south of Greenland and south of Iceland.

"The hills are alive to the sound of music".

Yes...just a brief lull before the next cold shot....that said UKMET not interested at 144 in anything like what EC shows...interesting times..

[northwestsnow]

EC  Is fabulous...Atlantic blocked...-NAO 

[That ECM]

9 minutes ago, knocker said:

All things considered the ecm quite close to the gfs with cold air shunted south next weekend as the ridge comes under pressure from a strong jet running across the south of Greenland and south of Iceland.

"The hills are alive to the sound of music".

Morning knocker. Sorry to hear your feeling unwell. 

I find it interesting/intriguing that the block just rebuilds all be it in different locations depending on the run. The timing is different on the runs but it doesn't get flattened and that's the end of it. 

 

This morning, ecm and gfs go a similar route and although gfs takes longer it ends up not dissimilar to ecm. For many a year a ridge would try and build, it would get flattened and it would be game over. 

The hills may come alive but with sound of screaming kids and us coldie nutters throwing ourselves down them.

 

[Dennis]

ok lets focus first on next week : good blocking -massive

Edited November 26, 2017 by Dennis