Model Output Discussion 01/09/17

[Mucka]

This is really knife edge stuff.

One or two more GFS ensembles eject the shortwave SE (oops posted SW) and push the Atlantic low South keeping us on the cold side of the flow than have in recent runs.

P2 an example of something we want to see more of but there are a whole range of possibilities still on offer, some bring southerlies, some bring wet and windy, some dry and cool, some cold and all of it underpinned by how energy is split in the Atlantic against the block in just 3/4 days time so we really should know by end of tomorrow.

But 13 is the lucky number as p13 has been rock solid today with this outcome

 

Edited November 15, 2017 by Mucka

[MattTarrant]

5 minutes ago, jules216 said:

Hi guys, sorry for maybe off topic question, but I think it might be model related as we stand, is it true that models have lack of satellite data over Greenland?

I saw it written here before when models had no clue during blocking period,could that contribute to the fact of huge swings and forecast uncertainty even at 5 days range?

If so, is there any link to official sources that could confirm this?

 

thanks 

https://www.metcheck.com/WEATHER/discussion.asp?DiscussionID=971&DiscussionTitle=Model+Blind+Spots

Read this from Metcheck which gives a good insight to the input of data. 

[Tracy Flick]

7 minutes ago, jules216 said:

Hi guys, sorry for maybe off topic question, but I think it might be model related as we stand, is it true that models have lack of satellite data over Greenland?

I saw it written here before when models had no clue during blocking period,could that contribute to the fact of huge swings and forecast uncertainty even at 5 days range?

If so, is there any link to official sources that could confirm this?

 

thanks 

I think Greenland's problem is it's altitude... the raw data has to be adjusted to sea level values(?)

[Radiating Dendrite]

1 minute ago, Luke Best said:

Boo hoo, you sound of reason you!

The mood changes in here every six hours. It's best to be realistic and expect the climatic norm with anything different to this a bonus!

The models frequently change in FI - this is not something only occurring at this time of the year. The difference is the number of eyes viewing them and every minimal change compared to summer. 

[booferking]

2 minutes ago, Mucka said:

This is really knife edge stuff.

One or two more GFS ensembles eject the shortwave SW and push the Atlantic low South keeping us on the cold side of the flow than have in recent runs.

P2 an example of something we want to see more of but there are a whole range of possibilities still on offer, some bring southerlies, some bring wet and windy, some dry and cool, some cold and all of it underpinned by how energy is split in the Atlantic against the block in just 3/4 days time so we really should know by end of tomorrow.

But 13 is the lucky number as p13 has been rock solid today with this outcome

 

There's a few P2 P13 P20 P10 hopefully the trend grows.

[PLANET THANET]

28 minutes ago, snowray said:

Not quite an easterly, but this is even better, nationwide snowfall, temps of around 0c.

unfortunately not quite nationwide according to the precipitation chart,kent and the southwest seem to miss out on this hit (if it happens)

[Mucka]

Just now, booferking said:

There's a few P2 P13 P20 P10 hopefully the trend grows.

Yeah let's hope so. Just noticed I wrote eject shortwave SW but obviously meant SE (corrected in my post)

At least there is more than one route to maintaining the block and drawing in cold - either energy splitting favourably or the low simply being modelled further W and S so the ridge is maintained and we stay on the cold side or something messier - I'm not fussy.

Be great to get at least some snow fall to low levels to complete some great early season model watching - such fickle creatures.

[Summer Sun]

15 minutes ago, northwestsnow said:

GFS12z is much better but im afraid from what i can see ukmo is poor at 144 for cold the heights across Greenland have already become detached.

-8 850's approaching Scotland

[northwestsnow]

3 minutes ago, Summer Sun said:

-8 850's approaching Scotland

Yes mate but i doubt those colder uppers will get much further south than that, ukmo/gfs are chalk and cheese at 144, just look at the heights building across Europe on ukmo.

ps I didnt even know you could access 850's on ukmo, cheers Gavin.:)

Edited November 15, 2017 by northwestsnow

[Sweatyman]

1 hour ago, tight isobar said:

Tbf after 144..

Its a case of throwing darts in the dark..

Crossboard...

Lets see what ec-says 120/240 hrs.

On its 12z.

 

6z

12z

I mean! What a crazy difference.

[tight isobar]

6 minutes ago, Sweatyman said:

I mean! What a crazy difference.

Purposely' selected next frame snapshot of 6z..before 12z. So for bringing into better time frame...

And yes' complete divergance!

Against its sister suite! ..

GFS

Edited November 15, 2017 by tight isobar

[Team Jo]

Gosh 113 browsing, There’s a lot riding on the ECM tonight! 

Before it rolls, just a gentle reminder that there’s the Moan/Ramp thread and local regional threads for chewing the fat over if it’ll snow in your back garden or sobbing into your horlicks - depending on your preference. 

 

[Summer Sun]

The 12z Op is very much on the colder side of the mean and control this afternoon beyond the end of next week up to next Thursday we have fairly good agreement

Edited November 15, 2017 by Summer Sun

[snowray]

33 minutes ago, PLANET THANET said:

unfortunately not quite nationwide according to the precipitation chart,kent and the southwest seem to miss out on this hit (if it happens)

Well its never been a precise science trying to predict snow at +T336, lets say 90% of the country then, that ok?

[nick sussex]

What drama!  I don’t want to open Pandora’s box with the issue of data coverage in some key areas but this can be a factor . 

You can read that from the horses mouth and tonight’s NOAA extended discussion.

They mention upper energy in data sparse regions north of Alaska and Russia and they do sometimes allude to data problems  in previous discussions I’ve read .

The issue we’re seeing is the exact orientation of blocking and height seepage , that’s my new term for this winter ! Lol

As I mentioned earlier today we want the blocking boxed in and not allowed to seep towards Canada  because this then puts less forcing on energy in the Atlantic .

Effectively we want the main block to remain as far east as possible so to avoid the dreaded west neg NAO.

 

Edited November 15, 2017 by nick sussex

[ICE COLD]

12 minutes ago, Summer Sun said:

The 12z mean is very much on the colder side of the mean and control this afternoon beyond the end of next week up to next Thursday we have fairly good agreement

You mean the operational Gavin  lol

[SMU]

Just to add Nick auto default will be low pressure not high pressure!

[PLANET THANET]

2 minutes ago, snowray said:

Well its never been a precise science trying to predict snow at +T336, lets say 90% of the country then, that ok?

sorry about that, i wasnt being picky. just that we never seem to get anything here 

[northwestsnow]

Just now, Steve Murr said:

Just to add Nick auto default will be low pressure not high pressure!

Steve/nick id be interested in your thoughts on ukmo this evening- while gfs is brimming with potential at 144 im not liking the look of ukmo..

[Cloud 10]

2 minutes ago, nick sussex said:

What drama!  I don’t want to open Pandora’s box with the issue of data coverage in some key areas but this can be a factor . 

You can read that from the horses mouth and tonight’s NOAA extended discussion.

They mention upper energy in data sparse regions north of Alaska and Russia and they do sometimes allude to data problems  in previous discussions I’ve read .

The issue were seeing is the exact orientation of blocking and height seepage , that’s my new term for this winter ! Lol

As I mentioned earlier today we want the blocking boxed in and not allowed to seep towards Canada  because this then puts less forcing on energy in the Atlantic .

Effectively we want the main block to remain as far east as possible so to avoid the dreaded west neg NAO.

 

 

"height seepage"

 

I like that one.

[karlos1983]

Blimey, 3 hour drive home and I miss all the drama. 

Big ECM coming up. 

[tight isobar]

8 minutes ago, nick sussex said:

What drama!  I don’t want to open Pandora’s box with the issue of data coverage in some key areas but this can be a factor . 

You can read that from the horses mouth and tonight’s NOAA extended discussion.

They mention upper energy in data sparse regions north of Alaska and Russia and they do sometimes allude to data problems  in previous discussions I’ve read .

The issue we’re seeing is the exact orientation of blocking and height seepage , that’s my new term for this winter ! Lol

As I mentioned earlier today we want the blocking boxed in and not allowed to seep towards Canada  because this then puts less forcing on energy in the Atlantic .

Effectively we want the main block to remain as far east as possible so to avoid the dreaded west neg NAO.

 

Good luck with that.(seepage)

I used the term to explain blocking releasing cold from the arctic some time ago....'cold seepage' and had my #### ripped...

?

[Mucka]

2 minutes ago, tight isobar said:

Good luck with that.(seepage)

I used the term to explain blocking releasing cold from the arctic some time ago....'cold seepage' and had my #### ripped...

?

Hope the a** ripping didn't cause any "seepage"

[Man With Beard]

I think the key to a colder run is more heights to our west by T96. That gives time for the Atlantic heights to make a strong link up with heights coming from Greenland.

I don't think the ECM is as amplified as the GFS at the timeframe but a. that doesn't make it right and b. let's wait and see...

[Tracy Flick]

30 minutes ago, Summer Sun said:

The 12z Op is very much on the colder side of the mean and control this afternoon beyond the end of next week up to next Thursday we have fairly good agreement

Yes, a cursory glance at the GEFS suggests excitement should be reined in, at least for a little while longer.  Westerlies still seem to have the upper hand IMO.