Uk Cold-Svalbard Hi Pressure Challenge

[SMU]

Ok People heres a challenge suited to old & new-

For me the biggest issue in recent years in terms of not getting very cold air in from the continent generating frontal snow is the area around Svalbard & West out to greenland persistently having low heights & low pressure- the net of this being there always a 200Mb influenceon any high pressure forming over Scandi- stopping it retrograding NW-

I challenge anyone to find any DECENT high pressure over svalbard having a net effect ofcold air over the UK -in the last 20 years-

I think there will be less than 5!!!!!!!!!!!

http://www.wetterzentrale.de/pics/archive/ra/1985/Rrea00119850102.gif this was from 25 years ago ( all but) -

remember you need heights over 552 DAM ( first yellow on the WZ charts)

Steve..........

[Duane S.]

Not so easy this challenge! Certainly is a rare beast.

I found this one but I've just noticed it was supposed to be in the past 5 years, doh!!

http://www.wetterzentrale.de/pics/archive/ra/1956/Rrea00119560203.gif

[Snowmad79]

This is one of the key factors in the christmas pudding.

Here is one, actually not from the last decent winter (95/96) but from the December of that year. This brought continual snow showers across my area, and I assume many other areas, on New Years Eve.

http://www.wzkarten....00119961231.gif

This will be a challenge for Mr Data and others who may claim that the christmas pudding is nothing new/special !

Damn ya beat me. Was about to say theres quite a few from winter 2005/2006. This one looks similar to that posted by Steve :

[rug]

Ok People heres a challenge suited to old & new-

For me the biggest issue in recent years in terms of not getting very cold air in from the continent generating frontal snow is the area around Svalbard & West out to greenland persistently having low heights & low pressure- the net of this being there always a 200Mb influenceon any high pressure forming over Scandi- stopping it retrograding NW-

I challenge anyone to find any DECENT high pressure over svalbard having a net effect ofcold air over the UK -in the last 20 years-

I think there will be less than 5!!!!!!!!!!!

http://www.wetterzentrale.de/pics/archive/ra/1985/Rrea00119850102.gif this was from 25 years ago ( all but) -

remember you need heights over 552 DAM ( first yellow on the WZ charts)

Steve..........

Hi,

Sorry, too technically limited to enter this quiz but just wanted to say how much I enjoy Steve M posts and hope he will be with us for this winter rollercoaster ride !

Thanks

[I remember Atlantic 252]

7th December 2002? yellow colours up that area, remember it, twas certainly cold!

[damianslaw]

Is this the scenario when the so called arctic high influences our weather, I'll be surprised then if anyone can show any in the last 20 years.

Along with 1985 I think feb 86 may have come close although the high was further south.

[LomondSnowstorm]

7th December 2002? yellow colours up that area, remember it, twas certainly cold!

yep, that's once so far!

[Tom Montalbano]

Hi Steve,

Nice to see you around, thats a real toughy you've set there. I've had a quick look through the archives and had a quick look at some of the colder winters since 62/63 and tbh, couldnt find any examples of "yellow" over Svarlbard. Strangely enough one of the closest examples I could find was from that spell of excellent northern blocking in late Feb/early March of 2005.

http://www.wetterzentrale.de/pics/archive/ra/2005/Rrea00120050222.gif

Although a trough is evident and moving in to Svarlbard, there are some decent heights just to the south of the island.

Looking south you can see that the U.K. is under PC air from an easterly flow, albeit not an especially cold one. The weeks leading up to this spell had been particularly mild over Northern and Eastern Europe and so temps weren't as cold as they could've been from this sort of set-up. Soil temps were anomalously high as well and snowfalls that did occur didnt settle that well and only when snowfall became heavy was there any appreciable settling. Even so my area recorded a couple of Thames streamer events and indeed I observed snow falling on consecutive days for nearly 2 weeks, an impressive stat in any winter, although, apart from a couple of days, snowfall was mainly in flurry form.

Having looked at the charts for Jan/Feb 1985, I must say there was some decent blocking at times in between Greenland and Scandinavia.

Regards,

Tom.

[Tom Montalbano]

A few charts from further back, Feb 1956, a very blocked month over Scandinavia and Greenland eventually.

http://www.wetterzentrale.de/pics/archive/ra/1956/Rrea00119560201.gif

http://www.wetterzentrale.de/pics/archive/ra/1956/Rrea00119560202.gif

http://www.wetterzentrale.de/pics/archive/ra/1956/Rrea00119560209.gif

http://www.wetterzentrale.de/pics/archive/ra/1956/Rrea00119560216.gif

Regards,

Tom.

[Thundery wintry showers]

The December 2002 easterly had the Scandinavian High the wrong shape and while it was very cold at the time in many parts of eastern Europe, that cold air failed to make it across to Britain. The spell was predominantly dull and dry with stratocumulus trapped under an inversion, except in parts of the west where it was sunny.

I don't think a Svalbard Low is necessarily the main problem, for as the New Year's Eve 1996 chart shows, you can have a low there but high pressure sandwiched between Svalbard and Britain delivering a cold east-north-east flow. The 30th/31st December 1996 was arguably the most recent instance of an easterly that brought widespread maxima close to zero, snowfalls and snow cover to Britain although a case can be made for the 27th-29th December 2005, at least for eastern areas.

Talking of which, here it is, and you can see that pressure is relatively low to the north of Svalbard.

http://www.wzkarten.de/pics/archive/ra/2005/Rrea00120051228.gif

Further back this famous easterly spell had a low over Svalbard:

http://www.wzkarten.de/pics/archive/ra/1987/Rrea00119870112.gif

For me the biggest problem for cold and snow has always been low pressure in the region to the west and south-west of Svalbard, particularly the Greenland/Iceland area- this serves both to cut off the polar air in northerly regimes and to prevent high pressure over Scandinavia from getting far west enough to direct polar or arctic continental air directly across to Britain.

[Duane S.]

I have just imported the past 60 years worth of the monthly mean AO index figures and interestingly found that only Dec '95 and Dec'00 featured in the lowest 20 monthly figures over the 1950-present period. However it was equally interesting to note that 11 out of the 20 lowest AO months featured in an 11 year period between 1958 and 1969.

Conversely, peak +AO monthly activity was between 1988 and 1997 and thereafter there are only 2 months which had a month in the highest 20 +AO months between 1950 and now!!

Another quick observation was two notably relative 'neutral' periods, one from 1950-1958 and another from 1996-present!

I know this may not be the entirely the correct way of obtain an annual mean but it'll do for this, anyway I then averaged each year's monthly AO mean results and imposed conditional formating using a graded colour scale(from red denoting the highest AO value to blue denoting the lowest AO value), there was then a fairly graphic representation of how our winters have panned out. early on from 1950 through until the mid sixties was relatively blue, later on reds ruled the roost although it was very notable how red the period between 1988-1994 was!

I bunged this into a graph, which I've attatched, and it shows how much more common a -AO year was earlier on in the period from 1950-present

ao_chart.docx

OMG am I agreeing with 'the christmas pudding'!!! No! I personally think this is part of a bigger cycle that has already started to plataeu and that we will see begin to reverse over the next couple of decades or so. If we had carried on getting strong +AO annual values that occured from the supposed beginning of this mythical era in 1989 through to 1994 until now then I may be left seriously wondering but the fact is that this didn't occur, as this chart shows...

ao_chart1989.docx

Now, I am not indicating that -AO equals the scenario we are looking for here (although it is a pretty decent indicator) or that it equates to cold weather for us (quite the opposite sometimes in fact) but the lowest mean -AO month was Jan 1963!!

Edited November 8, 2009 by s4lancia

[Rob]

i was going to suggest the winter of 05/06 but i've been beaten.

[Weather-history]

yep, that's once so far!

Is it?

I'm confused here because the centre of the high pressure is sat over Scandinavia and not over the Svalbard area. Yes the Svalbard area is yellow but there have been colder easterlies than this as TWS has shown where that region is not under high pressure.

The other example given is Feb 2006, not once is the Svalbard area under yellow.

As Tom has said I looked at 1962-63 and 1978-79 and the Svalbard area was hardly under yellow during those famous winters.

Edited November 9, 2009 by Mr_Data

[Tom Montalbano]

I would agree to a certain extent with Ian (TWS) that the problem area, certainly in regard to Polar Continental outbreaks, is the region between Iceland/Norway. If you look at the majority of classic PC outbreaks you'll find some yellow around the Iceland/Norway area. These heights being a major factor in allowing bitter air from Eastern Europe and beyond making all the way across the U.K. The problem in recent years is that the real decent heights have been confined to Eastern Scandinavia with the jet crashing through the GIN corridor and any PC air has been held well to the east.

I'm sure you'll be able to find examples when an easterly developed without decent heights in the Iceland/Norway area. One classic example was Dec 30th/31st 1978, decent heights over Greenland, jet running south of the U.K. and very strong PV sitting to the north of NW Russia.

To get a really decent northerly you need to see those green/yellows further west towards Greenland.

Must go now, otherwise I'll be late for work.

Regards,

Tom.

Edited November 9, 2009 by TomSE20

[Snowyowl9]

Just had a quick look but can`t find anything quite like January 1985.

Apart whats already been posted,february 2005/2006 are the only ones come to mind and 1996.

A couple like this.

http://www.wetterzentrale.de/archive/ra/2003/Rrea00120030106.gif

http://www.wetterzentrale.de/archive/ra/2001/Rrea00120010111.gif

Edited November 9, 2009 by Snowyowl9

[Weather-history]

Just had a quick look but can`t find anything quite like January 1985.

Apart whats already been posted,february 2005/2006 are the only ones come to mind and 1996.

A couple like this.

http://www.wetterzentrale.de/archive/ra/2003/Rrea00120030106.gif

http://www.wetterzentrale.de/archive/ra/2001/Rrea00120010111.gif

But the Svalbard area is not under yellow in both those charts. That region is under low pressure.

I ringed the Svalbard area here

Edited November 9, 2009 by Mr_Data

[Polar Continental]

As Mr Data mentions above, some of the charts in this thread, well most actually don’t show a decent high over Svalbard, I have trawled through the charts of all the colder months over the last 20 years and cannot find 1. The only one shown on this page is from Steve, but doesn’t count, as it was 1985.

I suppose there must be one somewhere!

I give up, no gold star for me.

Here is another one that doesn't count, but it did produce the goods.

[SMU]

A couple of contenders-

thisV

http://www.wetterzentrale.de/archive/ra/1987/Rrea00119870108.gif

others:-

Pressure was highish over svalbard X2 days before- With the core of the 552 zone further west-

This will trump most easterlies & is hardly ever mentioned- 80mph easterlies-

http://www.wetterzentrale.de/archive/ra/1952/Rrea00119520329.gif

heres one from the historic winter-

http://www.wetterzentrale.de/archive/ra/1963/Rrea00119630207.gif

another nearly-

http://www.wetterzentrale.de/archive/ra/1970/Rrea00119700306.gif

classic at the wrong time- havent seen that type of chart in years-

http://www.wetterzentrale.de/archive/ra/2003/Rrea00120031020.gif

the best nearly chart in history- but shows what happens when 552 dam is reached over svalbard-

http://www.wetterzentrale.de/archive/ra/2001/Rrea00120010203.gif

S

Edited November 9, 2009 by Steve Murr

[ribster]

Interesting thread, but I would also be interested in knowing if there is another period in the last 100 years or so (possibly longer) where there was a period of 20 years with no decent high pressure over Svalbard/Greenland during the winter?

Edited November 9, 2009 by ribster

[Optimus Prime]

February 1994 had a rather messy scenario but I think it counts;

February 1991;

February 1986;

[cheeky_monkey]

i know it is outside the twenty year time frame..but what about this one?

[SMU]

i know it is outside the twenty year time frame..but what about this one?

perfect

Steve

[Snowyowl9]

But the Svalbard area is not under yellow in both those charts. That region is under low pressure.

I ringed the Svalbard area here

This one is the best I can find in the last 20 years.

[chionomaniac]

Does this one count?

[SLEETY]

:lol::lol: Here's hoping anyway