Model output discussion - winter proper underway

[karlos1983]

Best set of ensembles we’ve seen for a while in the extended. 

 

[swfc]

Looking towards xmas on the 12z it probably wouldn't need much more ridging to bring wintry weather to quite a few northern areas,be it transient. Im not sure if its just me but im struggling to grasp the implications"nhp and weather" in regard to the background signals ie enso,pna,ssw.where if at all is the form horse ie east,north in regard to any cold outbreak

Imo "limited away from charts" id be looking nnw

[tinybill]

all i can say will it or wont it on the big day!!  one  day  it say rain now its saying it might be white  !!

[bluearmy]

9 minutes ago, karlos1983 said:

Best set of ensembles we’ve seen for a while in the extended. 

 

I thought yesterday's 12z was better clustered cold karlos 

 

[karlos1983]

9 minutes ago, bluearmy said:

I thought yesterday's 12z was better clustered cold karlos 

 

Must have missed them. Perhaps I should have said “that I’ve seen for a while” 

still not too bad 

[phil nw.]

After a fairly quiet week with some mild days as the Azores high ridges in It looks like all change in week 2.There seems to be quite an unsettled and possibly stormy period building up especially after Christmas as the vortex winds up to our north.

Some gef stamps from the 06z run for the 27th as a snapshot for that period

  

and a look at the 00z ecm mean for that day

The upstream East Pacific ridging pushing a large chunk of the vortex this way.A typical mid Winter +NAO setup with deep low pressure around the Iceland area very mobile sometimes quite chilly especially further north as the polar front tracks further south with time.

Edited December 17, 2017 by phil nw.

[Weather-history]

2 hours ago, Weather-history said:

Not far off from a January 1984 type set up

January 1984

Interestingly the start of March 1995 also has a large area of high pressure over the USA. 

[Ravelin]

2 hours ago, Daniel* said:

Well the snow would really pile over the mountains it can be quite snowy to quite low levels in the N/NW however it tends to not stick about as long did winter 2014/2015 bury the mountains?  

Yes, some of the deepest snow at Glenshee that I've ever seen, and most of the ski resorts spent lots of effort digging out lifts. There was a very distinct, and fairly high snow line though, luckily for Glenshee it sat just below the lowest point to of the resort but I don't think The Lecht did as well,  being lower. 

A cold/cool NW zonal flow is probably the best base building weather for the Scottish Ski resorts as it tends to bring much more precipitation than a northerly or easterly. 

Getting back on track, I'm not sure the models really have much of a clue at the moment past mid week. As the chart below for my location shows, they start to diverge around the 22nd, but the last few runs the red mean line beyond then has slowly been dropping. 

[comet]

Positive changes in model output so far today. Ridge from  Alaska looking stronger with each run could mean the UK finding  itself in a colder wintry pattern within the next 10 days as pressure builds to the west north/west allowing a growing nw/se trajectory. With more changes expected in the near term rather pointless looking to far ahead. As some have said a white Christmas or at least snow falling could now be on the table for some at least.

[Dennis]

watch the ridge posibility at the south of USA NE low

Edited December 17, 2017 by Dennis

[booferking]

51 minutes ago, FiftyShadesofWine said:

Jan 84 was a very stormy month, excellent summary from WeatherHistory here, not without some falling snow either...

Interesting Met office update 16-30 dayer though again, 

Number of days with falling sleet/snow wouldn't begrudge Jan 84 type setup that's for sure.

Belfast: 22

Glasgow: 20

Manchester: 13

Birminghan: 12

Cardiff: 12

Heathrow: 8

Plymouth: 6

 

 

 

 

[booferking]

CFS going off on one are is it onto to something here???

[bluearmy]

57 minutes ago, FiftyShadesofWine said:

 

Interesting Met office update 16-30 dayer though again, 

states much uncertainty (even more so than before I think)  and removes the snow word from the last sentence. That presumably a reflection of glosea removing its ssw 

latest mjo forecasts from NOAA models seem to drift the signal in phase 6 for a while. Ecm not updated since Friday 

[Deep Snow please]

7 minutes ago, booferking said:

CFS going off on one are is it onto to something here???

Could be onto something, Need to see if any other models follow it; certainly a plausible resolution.

[bluearmy]

23 minutes ago, Deep Snow please said:

Could be onto something, Need to see if any other models follow it; certainly a plausible resolution.

There are four cfs runs - the other three are different for that initialisation time.  I have more faith in a dice and a hat than the cfs! 

[LRD]

32 minutes ago, bluearmy said:

states much uncertainty (even more so than before I think)  and removes the snow word from the last sentence. That presumably a reflection of glosea removing its ssw 

latest mjo forecasts from NOAA models seem to drift the signal in phase 6 for a while. Ecm not updated since Friday 

I should know this but can NW Europe have a cold spell without a SSW? Or have SSWs been proved to be the be all and end all? Surely we've had cold spells without them? Glosea is a good model so this is disappointing news

[shotski]

Just now, LRD said:

I should know this but can NW Europe have a cold spell without a SSW? Or have SSWs been proved to be the be all and end all? Surely we've had cold spells without them? Glosea is a good model so this is disappointing news

We’ve just had a cold spell ?

[LRD]

1 minute ago, shotski said:

We’ve just had a cold spell ?

Of a massive 5 days, yes. Legendary stuff. OK let me ask the question in a different way which might negate a sarcastic response... have we ever had below average winter months without a SSW playing a part?

[shotski]

2 minutes ago, LRD said:

Of a massive 5 days, yes. Legendary stuff. OK let me ask the question in a different way which might negate a sarcastic response... have we ever had below average winter months without a SSW playing a part?

It wasn’t a sarcastic response, it was a noticeable cold spell for the British isles. What sort of weather are we expecting ? Still lying snow here as I type. 

[karlos1983]

6 minutes ago, LRD said:

Of a massive 5 days, yes. Legendary stuff. OK let me ask the question in a different way which might negate a sarcastic response... have we ever had below average winter months without a SSW playing a part?

SSW certainly improve our chances of a cold spell. Can we have cold winters without one? Yes, I think there have been memorable ones. I can’t quote the years as I struggle to remember last week at the best of times lol,  But it is definitely possible. A SSW doesn’t garauntee the uk a prolonged cold spell either, just that cold is more likely to spread to lower latitudes, obviously not all though.

Edited December 17, 2017 by karlos1983

[ArHu3]

7 minutes ago, LRD said:

I should know this but can NW Europe have a cold spell without a SSW? Or have SSWs been proved to be the be all and end all? Surely we've had cold spells without them? Glosea is a good model so this is disappointing news

 

Here is a list of all major midwinter warmings, you can see some winters with these warnings sucked too and some other great winters had no warming 

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/northpole/index.html

[LRD]

Just now, shotski said:

It wasn’t a sarcastic response, it was a noticeable cold spell for the British isles. What sort of weather are we expecting ? Still lying snow here as I type. 

Notable cold spell? Not for me. It was standard really. If we're relying on a SSW and Glosea is losing the signal for one in January, it's a worry

[LRD]

Thanks for the replies Karlos and ArHu3

[karlos1983]

Just out of interest, where did we hear that Glosea is losing the SSW signal? I can’t see any tweets from Ian F about it, and do they mean losing or lost? TIA, 

[ArHu3]

1 minute ago, karlos1983 said:

Just out of interest, where did we hear that Glosea is losing the SSW signal? I can’t see any tweets from Ian F about it, and do they mean losing or lost? TIA,