Model Output Discussion - cold spell to end Autumn

[Nick F]

Agreement by the models to flatten out the upper flow over the N Atlantic and lengthen the wave lengths late weekend and early next week in response to deamplification of the upper trough over eastern N America, hence the shift of low heights eastwards from the tropospheric PV over Canada across Greenland and merging with low heights over Scandinavia.

However, recent operational runs and ensembles indicating re-amplification mid week of the trough over eastern N America, which teleconnects to amplification of a ridge over N Atlantic again later in the week. With potential for a Nly reload from the arctic.

Looking further ahead, EPS H5 mean suggesting ridging NE towards Scandinavia day 14?

[northwestsnow]

1 minute ago, Nick F said:

Agreement by the models to flatten out the upper flow over the N Atlantic and lengthen the wave lengths late weekend and early next week in response to deamplification of the upper trough over eastern N America, hence the shift of low heights eastwards from the tropospheric PV over Canada across Greenland and merging with low heights over Scandinavia.

However, recent operational runs and ensembles indicating re-amplification mid week of the trough over eastern N America, which teleconnects to amplification of a ridge over N Atlantic again later in the week. With potential for a Nly reload from the arctic.

Looking further ahead, EPS H5 mean suggesting ridging NE towards Scandinavia day 14?

Perhaps more importantly no sign whatsoever of a euro high there nick- looks good.

[shaky]

5 minutes ago, northwestsnow said:

EC mean 120-

Hmm a really slidey mean at 120 hours!!does that mean some ensemble members take the slider further south and west still?

[northwestsnow]

Just now, shaky said:

Hmm a really slidey mean at 120 hours!!does that mean some ensemble members take the slider further south and west still?

Yes the mean is further south with the low..

[Ukwoody]

3 minutes ago, Nick F said:

Agreement by the models to flatten out the upper flow over the N Atlantic and lengthen the wave lengths late weekend and early next week in response to deamplification of the upper trough over eastern N America, hence the shift of low heights eastwards from the tropospheric PV over Canada across Greenland and merging with low heights over Scandinavia.

However, recent operational runs and ensembles indicating re-amplification mid week of the trough over eastern N America, which teleconnects to amplification of a ridge over N Atlantic again later in the week. With potential for a Nly reload from the arctic.

Looking further ahead, EPS H5 mean suggesting ridging NE towards Scandinavia day 14?

Can someone translate this into Numpty talk for me please??? lol

[Dean E]

30 minutes ago, Nicholas B said:

Haha! I think most regions have there own variations too. Like here in Lancashire its the m6 corridor, anything west of it is rain, sure the south east, north east, midlands, south west, wales & scotland all have them. Pop up on Sunday..ill show you what i mean lol! Sunday is going to shift we are only on Tuesday...which way is to be decided. Think BA is right in that by tomorrow tea we should have a decent though not fixed idea ?

I'm glad its not just restricted to us Southerners! 

I personally think its a few days off be nailed still, such shifts are still ongoing!

[Frosty.]

I see no reason to be downbeat post arctic shot, still looks on the cold side and cyclonic generally with some days colder than others, cold enough for sleet and snow, especially on higher ground and frosts / ice at night..potential for further more pronounced wintry outbreaks with the jet aligned nw / se.

Edited December 5, 2017 by Frosty.

[Winter Hill]

7 minutes ago, Ukwoody said:

Can someone translate this into Numpty talk for me please??? lol

Stop looking North West and start looking North East 

[BLAST FROM THE PAST]

10 minutes ago, Ukwoody said:

Can someone translate this into Numpty talk for me please??? lol

Northerly reload mid month with potential Scandinavia HP in 2 weeks time....easterlies?

 

back to more bullish post....reload to northerlies mid month due to Atlantic ridge....a given for me

 

BFTP

Edited December 5, 2017 by BLAST FROM THE PAST

[CanadaAl]

it's all about locale i guess. I can understand why those in the SE are feeling downbeat but it could all still change.

[BLAST FROM THE PAST]

1 minute ago, CanadaAl said:

it's all about locale i guess. I can understand why those in the SE are feeling downbeat but it could all still change.

I ain’t, it’s going to be very cold and not the 6c MetO/ BBC day......it didn’t get above 7c here today....so no chance will it be 6c

 

BFTP

[Scandinavian High.]

I don't think this a done deal yet with rain sleet and snow Sunday in to Monday history tells me the  whole lot could be pushed south and west we'll see how in all pans out next  couple days .   Before then we a Wintery weekend to come .

[ANYWEATHER]

Evening All, so can we see a Bartlett or Euro high from the ops today?  Its not on the scene and even the Azores high as no influence by day ten. Great news for coldies  but the devil will be in the detail ,and how many times have I said that? I think the Northeast of the uk will see proper winter in the days ahead , but plenty of time for all of us to enjoy winter....after all we are only on the cusp of Winter ,not the end of it....enjoy the ride folksRemember it does not have to be that cold to snow

[shotski]

8 minutes ago, BLAST FROM THE PAST said:

Northerly reload mid month with potential Scandinavia HP in 2 weeks time....easterlies?

 

back to more bullish post....reload to northerlies mid month due to Atlantic ridge....a given for me

 

BFTP

Just out of interest, when was the last time we had a sustained ridge over Scandinavia in December giving us easterly winds ? 

Isn’t it normally late Jan/feb when we would expect to see the beast ? 

[Frosty.]

With early yellow warnings for snow / ice already issued for quite a large swathe of the uk and set to be upgraded during the next few days..some of us are in for fun and games!..not often we see an arctic blast modelled in the reliable timeframe..going to enjoy watching it unfold.

Edited December 5, 2017 by Frosty.

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

"Sliders" can be challenging, especially for strong, stable and high pressureve. Conversely, as a slider, the lower flow in the north moves to high pressure. Many examples, including the least weight, low type, and so on. That does not mean that high blood pressure can increase, but the design of "W-E" lines!  (not like "e-w control").

[BLAST FROM THE PAST]

2 minutes ago, shotski said:

Just out of interest, when was the last time we had a sustained ridge over Scandinavia in December giving us easterly winds ? 

Isn’t it normally late Jan/feb when we would expect to see the beast ? 

Yep but just translating what is possibly suggested.  However Jan 1987 was from the 7th Jan with one of the most potent easterlies witnessed by anyone on here.  Nothing is written in stone as we all know

 

BFTP

Edited December 5, 2017 by BLAST FROM THE PAST

[BurwellWeatherWatch]

some nice charts tonight and could be some good surprises around this weekend. The route to cold and snow was never smooth for the UK but a difference of 100/200 miles is so tiny globally but very meaningful on the ground. On this basis, it's strange to hear people saying "GFS is cannon fodder" or "ECM now has egg all over its face". THe models are just playing around with solutions that are just really tiny on a global scale.

Looks like it could stay pretty cold into next week.

Some strange trollcasts on here tonight about zonality looking odds-on for next week. Of course it may happen but I don't see any particular evidence to back this up.

Great start to winter!

[I remember Atlantic 252]

1 minute ago, shotski said:

Just out of interest, when was the last time we had a sustained ridge over Scandinavia in December giving us easterly winds ? 

Isn’t it normally late Jan/feb when we would expect to see the beast ? 

'97 was good here, angle of attack was from SW, much better angle for snow

[Methuselah]

2 minutes ago, Frosty. said:

With early yellow warnings for snow / ice already issued for quite a large swathe of the uk and set to be upgraded during the next few days..some of us are in for fun and games!..not often we see an arctic blast modelled in the reliable timeframe..going to enjoy watching it unfold.

I think the last one I can remember was during the run-up to Xmas 1962? I even 'think' I can remember the late, great Michael Hunt saying that the sea started to freeze at Cromer, on Xmas eve...?

[Weegaz]

6 minutes ago, Frosty. said:

With early yellow warnings for snow / ice already issued for quite a large swathe of the uk and set to be upgraded during the next few days..some of us are in for fun and games!..not often we see an arctic blast modelled in the reliable timeframe..going to enjoy watching it unfold.

Me to frosty, looking forward to nowcasting and tracking the radar.

Being north and west (outside Belfast) we could do quite well in some of the heavier showers......i personally would be happy with a covering to make it feel somewhat festive this year.

Lets get the cold in and see where we go from there.

[LRD]

2 minutes ago, I remember Atlantic 252 said:

'97 was good here, angle of attack was from SW, much better angle for snow

That didn't sustain though. The pattern soon collapsed after that. But on the face of it, you'd think that would have been the precursor of a great winter. An almost-perfectly aligned Scandi High that looks robust. Just goes to show that the flimsiest of highs can drive a pattern south while a strong-looking high can collapse quickly. It turned out an exceptionally mild winter, of course, especially in the new year and that ridiculously warm February

[Iceaxecrampon]

3 hours ago, karlos1983 said:

Disappear might be a bit strong 

Some perspective 

Thats Sixteen days off.

[stewfox]

1 hour ago, Draig Goch said:

So many on here are saying the best chance of snow will be anywhere north of the M4. Luckily for me, I live 1 mile north of the M4 in South Wales but for those that live a couple of miles south of the M4, take a stroll over the footbridges and come join us in our magical winter wonderland when it arrives! 

 

 

Marginal event for many in the south but we will always have lamp posts so not all lost, could always change make the most of it . GFS 18z could be a corker. 

[offerman]

3 hours ago, Day 10 said:

I have placed this in the media thread also so please remove mods if you have to. I just thought it was a good read and is relevant right now

https://www.channel4.com/news/by/liam-dutton/blogs/why-you-shouldnt-believe-a-uk-snow-forecast-more-than-three-days-ahead

BEST POST OF THE YEAR!!! F1 charts forget 

and hjoae

3 day's out even two days ! I want snow as much as the next man but it is extremely frustrating and countless times charts predict snow only to downgrade but so rare the other way round.