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Paul

Model output discussion - here comes the beast!

Paul

Please only post model discussion in this thread 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

We also have a special post SSW cold spell discussion open here:
https://www.netweather.tv/forum/topic/89358-ssw-related-cold-spell-will-it-wont-it/

Thank you!

Message added by Paul

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runs up until now have shown most snowfall in n England and the midlands plus kent/Suffolk 

this run isn’t much different with more snow piling into ne England 

as far as I am concerned, we just want the deepest cold with the strongest flow - troughs will appear. 

For continuity sake, important to see the ecm op show a similar solution to the 00z run. A jump to cluster 2, would be a pain for confidence, depending on whether it had the accelerated easterly or not beforehand to soothe the discomfort !

Edited by Paul

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7 minutes ago, Captain Shortwave said:

A slightly odd set of statements given that the GFS doesn't deliver much snow to the south east. The majority hits NE England and Scotalnd like the previous runs (There will be chances of organised areas of snow that won't be picked up until within the 48 hour range.).

Exactly captain shortwave some truly bizarre posts in here,  note the little kink in the flow on the GFS already picking up on little features,  there will be many more as we get closer to the time

Screenshot_20180220-170126.png

Edited by seabreeze86

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8 minutes ago, Captain Shortwave said:

A slightly odd set of statements given that the GFS doesn't deliver much snow to the south east. The majority hits NE England and Eastern Scotalnd like the previous runs (There will be chances of organised areas of snow that won't be picked up until within the 48 hour range.).

A GFS precipitation chart I know, but the point is kind of made here to be honest.

192-780UK.GIF?20-12

This is correct, which is why it is strange that people seem to be okay in the south with the coldest uppers being cut off. They are needed for the convection that is not being shown on these charts. The high is modelled further south and it can be that sort of precipitation that dwindles. The further north the high, the better chances exist for south of the M4 (I lived there for over twenty years, I speak from experience!), 

Edited by ukpaul

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Just now, bluearmy said:

The se thing isn’t relevant at the moment

runs up until now have shown most snowfall in n England and the midlands plus kent/Suffolk 

this run isn’t much different with more snow piling into ne England 

as far as I am concerned, we just want the deepest cold with the strongest flow - troughs will appear. 

For continuity sake, important to see the ecm op show a similar solution to the 00z run. A jump to cluster 2, would be a pain for confidence, depending on whether it had the accelerated easterly or not beforehand to soothe the discomfort !

Then you want the high to be further North than the 12z Opp, that's the point really.

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1 minute ago, Mucka said:

Then you want the high to be further North than the 12z Opp, that's the point really.

Spot on mucka, the high further north gives Scotland a chance of joining in the siberian express and even more severe further south, similar to the 6z and Ecm 00z would be ideal..:)

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10 minutes ago, radiohead said:

GFS and UKMO are both very good up to 144. The "panic" is because of changes on the GFS beyond the range of the UKMO. They cannot be compared at that point.

 

I don't necessarily agree, you can see the rough transition that it was going to take (al la ECMWF op).

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Just had a look through all 20 GEFS ensembles plus the control at 192 hours and from all those there is only 1 ensemble member that follows the op run at that timeframe.

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3 minutes ago, Mucka said:

Then you want the high to be further North than the 12z Opp, that's the point really.

It’s a bit more complicated than that mucka  (re med and Azores Lows plus the flow from the east ) but yes, the surface high on gfs 12z is further sw than previous runs. 

Not sure how useful the gefs are going to be on this as some of the differences could be shortwave induced and the ens are less likely to pick these up. That’s why I said Thursdays 00z runs before being sure about longevity and intensity of next weeks cold. 

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4 minutes ago, bluearmy said:

It’s a bit more complicated than that mucka  (re med and Azores Lows plus the flow from the east ) but yes, the surface high on gfs 12z is further sw than previous runs. 

Not sure how useful the gefs are going to be on this as some of the differences could be shortwave induced and the ens are less likely to pick these up. That’s why I said Thursdays 00z runs before being sure about longevity and intensity of next weeks cold. 

Yeah it is always more complicated but in general terms we need a more favourable orientation and latitude of the block as it retrogresses than the Op to stay in a cold flow and increase chances of troughs making it across us or just maintaining good shower activity.

A few more options creeping into GFS ensembles along with the clean retrogression, but the majority have the high further West and North through the transition than the Op and are accordingly colder with better snow chances.

I just happened to be at P20 as I went through them but is an example of a more favourable retrogression of which there are thankfully many.

gensnh-20-1-204.png

 

Edited by Mucka

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1 minute ago, jethro said:

But to be fair when the North was buried in 2010, we got cold and mostly dry, a bit of snow but nothing memorable. March 2013.....we got a bit chilly, that was it. The North does extremely well usually, Scotland has had an amazing winter so far, we're all still foot tapping and hoping down here and have been for years.

The western half of Scotland has done extremely well this winter with the NW blasts earlier. If I said England had a great winter then that wouldn't be true because the midlands had some good snowfalls but many areas didn't. I'm in the east and we have only seen a fraction of the snow. It's not really about being "fair". It was model analysis. If I had my way I'd want us all to be buried under 2 ft of snow.

All that some folk away from the south of England were doing were commenting on the fact that the high pressure was affecting snow chances for the northern half of the UK. Hopefully, the ECM will continue with another stellar run like the 0z and we can all get back to what we do best - ramping. :D

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I'm a little confused why there is this all this caution with some , given the dynamics of what is happening the usual failure of an easterly is less likely. Are weather pattern has reversed so we look east/north east/ south east for prevailing weather, the only thing that could majorly effect that is where the HLB ends up, all the indications are favouring the southern half of the uk especially atm. With such cross model agreement it would seem we are in for some proper winter weather. Put it this way if it were raging south westerlys well..........Its great to see such charts atm but remember they are usually over done so we end up with something slightly watered down.

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A mere wobble from GFS 12Z snow apocalypse not budging...

60E24716-14CE-4254-9BA9-29E89CB4D89F.thumb.jpeg.5d3d6c4c4c022bac24d392801313215c.jpegvA6081C15-BB34-4DAB-9490-69FBF39AD2F0.thumb.jpeg.867a6e4537ba7a944e84652ba7dbf1b9.jpeg

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The ensembles are at least looking good still for the 12z GFS. The operational run is pretty much one of the warmer options from the 28th. The scatter does increase the further north you go though, showing the models are struggling with the position of the high pressure after the 27th.

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With regard to the upcoming ECM, it will be telling whether the op follows the earlier cluster with the HP further south. Don’t let us down ECM!

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The op should not be ruled out, it's on the table as a viable solution. I suspect the 12z has somewhat gone to the extreme and the upper high will get slightly dialed back. Intial thrust looking good still. Long term is varying degrees of cold.

This is still an exceptional run, you can count the number of colder easterlies on one hand from the last 50 years.

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9 minutes ago, radiohead said:

Just had a look through all 20 GEFS ensembles plus the control at 192 hours and from all those there is only 1 ensemble member that follows the op run at that timeframe.

No need to worry so the majority stick with the very cold air over us past 144☺

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1 minute ago, nick sussex said:

A lot of this is to do with timing.

The first chunk of cold and then the next one which the models have further east.

The second chunk will start heading west so it’s getting that into the UK before the models start developing the omega block.

As soon as that starts developing a trough will start to head south into Scandi.

You can see on the GFS this diverts the second cold chunk to the se of the UK.

To be honest I think there’s far too much worry about events past the initial first cold chunk when that’s not even settled yet in terms of depth of cold and how much instability there will be.

 

 

On the model output thread with an upcoming cold spell looming?

You crazy! :crazy:

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Well using my method Spring isn’t gonna really arrive until late in April.....and this is deeper cold than I anticipated..... I ain’t worried at all 😎😜 

 

BFTP

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1 minute ago, nick sussex said:

A lot of this is to do with timing.

The first chunk of cold and then the next one which the models have further east.

The second chunk will start heading west so it’s getting that into the UK before the models start developing the omega block.

As soon as that starts developing a trough will start to head south into Scandi.

You can see on the GFS this diverts the second cold chunk to the se of the UK.

To be honest I think there’s far too much worry about events past the initial first cold chunk when that’s not even settled yet in terms of depth of cold and how much instability there will be.

 

 

Agreed Nick. Don't get what the toy throwing is about to be honest, yes the GFS was not as severe as the 6z but so what still a good run and clearly on the top end of the pack with regards to the HP positioning.

A nice ECM will calm the nerves.

Green/Green plus on the warning system?

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