Model output discussion - The Hunt For Cold

[Iceaxecrampon]

6 hours ago, northwestsnow said:

Looks to be growing support for a brief northerly next weekend.

I do love working nights as we reach Autumn / winter as i get 1st glimpse of the 00z runs.

And yes everyone at work thinks i'm strange !! 

 

Yes - First ppn for Scafell Pikes at 900m ASL?

[Iceaxecrampon]

Polar Low development for Halloween? - rare as Rocking Horse though.

[Skullzrulerz]

Although this may seen like a done case personally I wouldn't get too excited for two reasons...

One being that this is still a week away even though the models argee with a cold shot from the north of some kind hence in some kind the question bring it doesn't get wekaned during the time to if it happens.

Two even if the models argee with this spell there is however of how cold ? If it evens happens.

[Iceaxecrampon]

3 minutes ago, Frosty. said:

All I have to say about these charts from the Ecm 00z ensemble mean is.....B A N K!!

Yes - chilly potential coming through for next weekend on a few models and the METO?

[Iceaxecrampon]

Just now, Skullzrulerz said:

Although this may seen like a done case personally I wouldn't get too excited for two reasons...

One being that this is still a week away even though the models argee with a cold shot from the north of some kind hence in some kind the question bring it doesn't get wekaned during the time to if it happens.

Two even if the models argee with this spell there is however of how cold ? If it evens happens.

Might not as you say but as the thread is its the Hunt (and the eventual disappointment) 

[Tim Bland]

Just to keep things in perspective; The majority of charts I have seen (eg the ECM mean above) show uppers around -4c. At this time of year (sun still fairly strong) you need t850hpa of -6c or below to see anything wintry below around 400m. I’m encouraged by the pattern as hopefully it will repeat into Nov and Dec but I wouldn’t wax the sledges just yet...unless you are planning a trip to the top of Cairngorm 

[Jonathan Rhodri Roberts]

If only this was the end of November, we could have been looking at some impressive snow in that flow but as it'll only be the last day of British Summertime and the sea temperatures are still currently mild/ very mild in the Irish Sea, Bristol & English Channel as well as the southern part of the North Sea I doubt there'll be much to get excited over yet. Further north though it's a different story especially across high ground 

Edited October 20, 2018 by Jonathan Rhodri Roberts

[Mike Poole]

1 hour ago, bluearmy said:

As Steve comments, amazing gfs fi op on a hemispheric scale.......

anyone knows when it disappears and the gfsp replaces it ?????

According to this the parallel supposed to be fully operational sometime in 2019:

https://www.gfdl.noaa.gov/fv3/

i imagine as it's a completely different model, they will want a long test period, so I don't think we'll see the back of the current GFS for a while.  So probably have both available all winter!

Edited October 20, 2018 by Mike Poole

[Methuselah]

11 minutes ago, Jonathan Rhodri Roberts said:

If only this was the end of November, we could have been looking at some impressive snow in that flow but as it'll only be the last day of British Summertime and the sea temperatures are still currently mild/ very mild in the Irish Sea, Bristol & English Channel as well as the southern part of the North Sea I doubt there'll be much to get excited over yet. Further north though it's a different story especially across high ground 

Thundery and possibly wintry showers around all but southern coasts?

Edited October 20, 2018 by Ed Stone

[Iceaxecrampon]

06Z Out

Next weekend? 

 

Direct N feed - not sure about the temps though?

[Seasonal Trim]

55 minutes ago, Jonathan Rhodri Roberts said:

If only this was the end of November, we could have been looking at some impressive snow in that flow but as it'll only be the last day of British Summertime and the sea temperatures are still currently mild/ very mild in the Irish Sea, Bristol & English Channel as well as the southern part of the North Sea I doubt there'll be much to get excited over yet. Further north though it's a different story especially across high ground 

Sorry for my ignorance, but I was under the impression that warm seas were a good thing when it came to snow! I'm by no means an expert, so could somebody clear this up for me.

Edited October 20, 2018 by Nizzer

[Tim Bland]

10 minutes ago, Nizzer said:

Sorry for my ignorance, but I was under the impression that warm seas were a good thing when it came to snow! I'm by no means an expert, so could somebody clear this up for me.

Good for convection leading to precipitation..but bad for temperatures meaning it’s more likely to be rain rather than snow

[Iceaxecrampon]

12 minutes ago, Nizzer said:

Sorry for my ignorance, but I was under the impression that warm seas were a good thing when it came to snow! I'm by no means an expert, so could somebody clear this up for me.

SST (Surface Sea Temperatures) quite warm this time round especially after the Summer we've had - all has an effect alt Sea Level elevations *maybe not so much at altitude if there is an early Northern flow.

edit: *for snow that is

Edited October 20, 2018 by Iceaxecrampon

[Weather-history]

5 hours ago, Steve Murr said:

384 - possibly the biggest NAO /AO block in recorded history

[Midlands Ice Age]

22 minutes ago, Weather-history said:

Wow....

That will take some beating.

Can it be under threat this year with the signs of increased polar blocking?

MIA

[Mike Poole]

FV3 6z impressive run so far, here at T180 - next weekend - has the cold air sweeping south across the UK:

Again note the 4 waves on the NH plot.

Interestingly, FV3 is currently top dog on day 8 NH stats, GFS second, not often ECM knocked into third at this timeframe!

[Kirkcaldy Weather]

06z GEFS

P3  P5 brings in the first northerly earlier and also has a 2nd northerly going into November   P6   P9 & P10 nearly get the high pushing all the way into Greenland   P15 has a west based negative NAO  P18 with a nasty low/storm down the east coast  The main area to keep an eye on is the developing low over Greenland at the end of the month, if its too deep like on the main run of the 06z the northerly fails however some of the GEFS members have it weaker and allow the high to push into/towards Greenland leading to the northerly's 

[bluearmy]

 

 

2 hours ago, Mike Poole said:

 

Interestingly, FV3 is currently top dog on day 8 NH stats, GFS second, not often ECM knocked into third at this timeframe!

Interesting ..... anecdotally I haven’t been disappointed by the gfsp and look forward to seeing if it struggles over the next few months with separation of energy as is usual with the gfs over the years 

 

 

[Weather-history]

The northerly looks odds on, it's now becoming more of a case of just how cold will it be?

 

[SMU]

Subtle upgrades coming along with the GFS - Higher instability & a secondary pool of ~-6 to -8c air cod possible allow for a wider range of sleet & snow possibilities

Also the flow now taking on more of a NE component...

[Ali1977]

Much better run this, WAA right into central Greenland 

Edited October 20, 2018 by Ali1977

[Polar Maritime]

Certainly cold for all next weekend from the North, Turning N/Ely into the new week.

 

[Skullzrulerz]

Both AO And NAO go very negative the end of October through possible recovery to netural

[Derecho]

18 minutes ago, Polar Maritime said:

Certainly cold for all next weekend from the North, Turning N/Ely into the new week.

 

Almost certainly going to a very cold northerly later on this week with perhaps sleet or snow at lower levels if the GFS 12z is believed. Next question is how long will it last? Will the block become anchored over Greenland and keep the cold going? or will it be a toppler?

[Singularity]

Time for a couple of if onlys!

- If only it was a month or two later in time

- if only there weren't predominantly warm SSTs in the direction from which the flow will make its way down to us.

The second point does draw attention, though, to the fact that those SSTs to our N and NE are a lot less positive overall than seen for a number of years now. They're still very positive further afield in the Kara Sea though... which may mean we keep the additional height rise encouragement to our NE while benefiting from less moderation of cold air drawn from our N and NE during at least the early part of the coming winter. Provided we get such air flows, that is!