Unprecedented early intense Scandinavian high?

[xmetman]

Unprecedented early intense Scandinavian high?

The maximum central pressure of the anticyclone over Scandinavia at midnight (5 October 2016) was 1051 hPa, which I thought was very high and unusual for early October, so I went delving into the synoptic charts for pentad 56 (2-6 October) with the aid of the objective Lamb Weather Types [LWT] from the University of East Anglia [UEA]. The best analog I could find for it was way back in October 1881. Far from a perfect match I know, but it does go to show how rare such an early intense Scandinavian high are.  

[Dave C]

Going to bring a couple of weeks of fairly dull, chilly,boring weather here in Essex I feel. Be great if it the scenario returns next February though :-)

Dave

[Simon S]

Any reason for such a high to develop?
Is there any link to the track of the atlantic hurricane / tropical storms this season?

[Paul Garvey]

Therein lies the mystery!

[Richard Dixon]

Nice one Bruce. The first thing that has sprung to mind for me was whether early season Scandinavian blocking lowers the chance of later-season blocking when it has a decent chance of introducing properly cold air into the UK.

Richard 

[Stephen Davenport]

As I wrote elsewhere (and I might as well c&p it): The negative AO pattern we are seeing now in October, manifested by anomalous high pressure Siberia to Scandinavia (and the very strong anticyclone there) and also across Canada is likely due to high latitude temperature anomalies and decreased temperature gradient.

Meridionality/blocking around the NH is perhaps being amplified to a degree by re-curving typhoons.

Stephen
Indianapolis IN

[xmetman]

Yes, I suppose the big question is as Richard asked, will the blocking reoccur throughout the coming winter, or is this just a one off event while the atmosphere in the northern hemisphere rights itself?

[Scott Whitehead]

On Monday, October 10, 2016 at 7:28:27 PM UTC+1, Richard Dixon wrote:

Nice one Bruce. The first thing that has sprung to mind for me was whether early season Scandinavian blocking lowers the chance of later-season blocking when it has a decent chance of introducing properly cold air into the UK.

Richard 

Indeed. Ice in November to bear a duck and all that. Assuming it makes it to November? 

[xmetman]

But the British Isles are all surrounded by a mild ocean, and this year its a bit milder than usual in places. Even a Arctic northerly airstream right from the pole is now crossing a lot more open sea free of sea ice than it was a few years ago rather than from a very cold ice cap. I'm really starting to depress myself so I'll stop before I go any further😣

[Scott Whitehead]

On Wednesday, October 5, 2016 at 7:32:01 PM UTC+1, Dave C wrote:

Going to bring a couple of weeks of fairly dull, chilly,boring weather here in Essex I feel. Be great if it the scenario returns next February though :-)

 

 I was expecting the same, Dave, but it has been very sunny here: I've already recorded 54% of a normal October! Is it because there's still plenty of oomph in the sun to clear any early low cloud? Or is the very dry ground playing a part?

 

[Trevor Harley]

"Due to anomalies" - ah, but what causes those anomalies?

[Paul Garvey]

Northerlies ain't what they used to be! And a very good thing that is too! They aren't a great work for cold in South Devon anyway. Usually, a northerly here produces only a little below average temperatures and a nice dry, sunny winter's day.

[Joe]

I found this chart in the Net earlier in this morning.

My take on this and posted elsewhere was :

Here's an interesting set of charts based on a European seasonal forecasting model. The charts to the left show temperature and the ones to the right precipitation.

What's shown here suggests to me that over the months of Nov through Jan High pressure looks more dominant to our North or North West. This I derive from the fact that charts indicate drier (& "warmer") in those regions. I wouldn't be hung up on the temperature charts so much as High Pressure to our NW or N would bring winds from a cold direction, or N or NE.

Of course there would be milder and water interludes, possibly windy too, but overall the pattern suggests to me a COLDER and DRIER winter than previous.

If this holds true then good for the farmers down the country who need less rain.... But it would also bring about a greater chance of snowy and frosty weather at times, especially into January. We don't need much rain to get a lot of snow as we experienced in 2009/2010! Of course I'm not suggesting anything that bad again butwho knows?😉😎

I would in more than interested in an expert opinion, Bruce, or anyone?

[xmetman]

Joe

It would be nice to see the corresponding mean pressure chart and anomalies that must accompany the temperature and rainfall.

Everywhere looks mild or very mild November through January, especially the Arctic, but the negative SSTs in the central Atlantic always keep that cooler. 

As you say January seems cold over southern Norway and Sweden, as if the coolness in the central Atlantic has extended its grasp further eastward, that might indicate more anticyclonic blocks like the one we have at present but it's hard to say.

Bruce.

[Joe]

Hi Bruce.

Apologies for the typos throughout that waffling analysis. I am using a very small screen sized mobile with fat fingers. I had to turn off my Samsung Note 7 yesterday and today return it!

Here's the link. I didn't see pressure charts..yet.

http://forest.jrc.ec.europa.eu/effis/applications/long-term-forecast/seasonal-forecast/

[Paul Garvey]

You've got to come back to the probabilities of those charts achieving outcome. Nov-Jan (even Nov!) is a long way off and seasonal forecasting, by anyone shows poor accuracy over time. I'd take them with a large shovel of grit salt!

[Joe]

Well, Bruce, I was unable find corresponding pressure charts. 

The site does go into where it gets the data and how it is used.  It will be interesting to see how the charts reflect what actual happens as we close out each month. If I was patient enough, I'd retain each month's refresh, assess/compare changes run to run, and then 'measure' outcome over a period of time but I figure I'll be beyond retirement before I'd have enough data to make any reliable judgement of accuracy!

I did wonder if my interpretation of those charts was way off the mark and thanks Bruce for the steer. 

As for the value of such charts, I do look for trends in various charts like these, that attempt future modelling, to get a very general sense of what *might* be the more probable weather-type for the season.  However, at the end of the day, I wouldn't be foolish enough to back the outcome or make outlandish forecasts like Mr. Madden (aka. Nathan Rao's muppet).  It does make for interest though and it's good to see the continued research into long term forecasting whatever the conclusion.

Joe