My daughter texted me after reading something in the paper and I could give a balanced answer as to what effect this may or may not have on our weather and why, but what I couldn't answer was what causes this warming to occur.. Doing a quick search and I couldn't find the answer?

Is there a simple answer to this question?

Keith (Southend)

On Saturday, December 29, 2018 at 5:28:39 PM UTC, Keith Harris wrote:
My daughter texted me after reading something in the paper and I could give a balanced answer as to what effect this may or may not have on our weather and why, but what I couldn't answer was what causes this warming to occur. Doing a quick search and I couldn't find the answer?

Is there a simple answer to this question?

Keith (Southend)

A bit here, but it's pretty superficial, more or less stating what happens rather than why IMHO.
https://blog.metoffice.gov.uk/2013/0...c-warming-ssw/
The blaming it on a large high, could easily be reversed, blaming the large high on SSW.

I was looking for something rather more depth but couldn't find anything, so I'd be interested as well.

Graham
Penzance

In message ,
Graham Easterling writes
On Saturday, December 29, 2018 at 5:28:39 PM UTC, Keith Harris wrote:
My daughter texted me after reading something in the paper and I
could give a balanced answer as to what effect this may or may not
have on our weather and why, but what I couldn't answer was what
causes this warming to occur. Doing a quick search and I couldn't find
the answer?

Is there a simple answer to this question?

Keith (Southend)

A bit here, but it's pretty superficial, more or less stating what
happens rather than why IMHO.
https://blog.metoffice.gov.uk/2013/0...stratospheric-
warming-ssw/
The blaming it on a large high, could easily be reversed, blaming the
large high on SSW.

I was looking for something rather more depth but couldn't find
anything, so I'd be interested as well.

Graham
Penzance

Presumably it must be known what causes it, as the computer models
picked up on it well in advance. So if it's being modelled, it must be
reasonably well understood.
--
John Hall
"Hegel was right when he said that we learn from history
that man can never learn anything from history."
George Bernard Shaw (1856-1950)

On Saturday, December 29, 2018 at 7:18:14 PM UTC, John Hall wrote:
In message ,
Graham Easterling writes
On Saturday, December 29, 2018 at 5:28:39 PM UTC, Keith Harris wrote:
My daughter texted me after reading something in the paper and I
could give a balanced answer as to what effect this may or may not
have on our weather and why, but what I couldn't answer was what
causes this warming to occur. Doing a quick search and I couldn't find
the answer?

Is there a simple answer to this question?

Keith (Southend)

A bit here, but it's pretty superficial, more or less stating what
happens rather than why IMHO.
https://blog.metoffice.gov.uk/2013/0...stratospheric-
warming-ssw/
The blaming it on a large high, could easily be reversed, blaming the
large high on SSW.

I was looking for something rather more depth but couldn't find
anything, so I'd be interested as well.

Graham
Penzance

Presumably it must be known what causes it, as the computer models
picked up on it well in advance. So if it's being modelled, it must be
reasonably well understood.
--
John Hall
"Hegel was right when he said that we learn from history
that man can never learn anything from history."
George Bernard Shaw (1856-1950)

Not necessarily. Ahead of a warm front the visibility commonly becomes very good, high cloud streams in etc. It is therefore possible to forecast the likelyhood of rain followed by mizzle (certainly in Cornwall). The sequence is known without any need for an understanding of the mechanisms involved. Traditionally farmers fisherman etc. would forecast based purely on observations of the weather and an knowledge of the sequence of events.

In fact, because the main time Scilly is visible from Cornwall is ahead of an approaching warm front, there is a local sayng that "If you can see Scilly it's going to rain".

It would be good to have a detailed explanation of the evolution of a SSW event. At present it seems like a well kept secret (at least from me!) or it's rather predictable but little understood.

Graham
Penzance

On 29/12/2018 17:28, Keith Harris wrote:
My daughter texted me after reading something in the paper and I could give a balanced answer as to what effect this may or may not have on our weather and why, but what I couldn't answer was what causes this warming to occur.. Doing a quick search and I couldn't find the answer?

Is there a simple answer to this question?

Keith (Southend)


Very similar trans-polar dipole structure around 07 Feb 2016 as the
recent Xmas eve peaking for the stratosphere, eg.

http://www.meteociel.fr/modeles/gfse...para=0&carte=1

Graham Easterling wrote:

On Saturday, December 29, 2018 at 7:18:14 PM UTC, John Hall wrote:
In message ,
Graham Easterling writes
On Saturday, December 29, 2018 at 5:28:39 PM UTC, Keith Harris
wrote:
My daughter texted me after reading something in the paper and I
could give a balanced answer as to what effect this may or may
not have on our weather and why, but what I couldn't answer was
what causes this warming to occur. Doing a quick search and I
couldn't find the answer?

Is there a simple answer to this question?

Keith (Southend)

A bit here, but it's pretty superficial, more or less stating
what happens rather than why IMHO.
https://blog.metoffice.gov.uk/2013/0...udden-stratosp
heric- warming-ssw/
The blaming it on a large high, could easily be reversed, blaming
the large high on SSW.

I was looking for something rather more depth but couldn't find
anything, so I'd be interested as well.

Graham
Penzance

Presumably it must be known what causes it, as the computer models
picked up on it well in advance. So if it's being modelled, it must
be reasonably well understood.
--
John Hall
"Hegel was right when he said that we learn from
history that man can never learn anything from
history." George Bernard
Shaw (1856-1950)

Not necessarily. Ahead of a warm front the visibility commonly
becomes very good, high cloud streams in etc. It is therefore
possible to forecast the likelyhood of rain followed by mizzle
(certainly in Cornwall). The sequence is known without any need for
an understanding of the mechanisms involved. Traditionally farmers
fisherman etc. would forecast based purely on observations of the
weather and an knowledge of the sequence of events.

In fact, because the main time Scilly is visible from Cornwall is
ahead of an approaching warm front, there is a local sayng that "If
you can see Scilly it's going to rain".

It would be good to have a detailed explanation of the evolution of a
SSW event. At present it seems like a well kept secret (at least from
me!) or it's rather predictable but little understood.

Graham
Penzance

The same thing happens in the west of Scotland.. Visibility just ahaed
of a warm front is, typically, much better even than in cold arctic
outbreaks.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
twitter: @TideswellWeathr

This is MetO blog on the 2016 one

Professor Adam Scaife, Head of Monthly to Decadal Prediction explains:
“Sudden stratospheric warming events occur high up in the atmosphere and
involve a complete reversal of the high altitude polar jet stream – they
can even affect weather at the surface, and for the UK a sudden
stratospheric warming increases the risk of wintry weather.�

The phenomenon begins with a wave-like disturbance which travels up into
the high-altitude jet stream. Scaife said: “This disturbance can grow to
a point where it turns over and breaks, just like a wave on a beach.�

Normally the jet stream flows from west to east with some north and
south oscillation, but the force from this high altitude disturbance
pushes against the jet stream until the winds actually reverse and flow
from east to west instead. Air then falls into the Arctic and is
compressed so that it starts to warm: the temperature can rise by as
much as 50C in just a few days.

Professor Scaife added: “This reversal of high altitude winds can also
burrow down into the lower stratosphere. Once it is within reach of
weather systems in the lower atmosphere the Atlantic jet stream often
weakens and moves south. This allows cold air from the east into
northern Europe and the UK.�

https://blog.metoffice.gov.uk/2016/0...art-to-spring/

I see GFS has decided on another similar N-pole dipolar arrayment SSW
about 10 Jan 2019

On 31/12/2018 08:59, N_Cook wrote:
I see GFS has decided on another similar N-pole dipolar arrayment SSW
about 10 Jan 2019




GFS moved it forward to 09 Jan with the balancing/consequential?
diametric cold pool over the UK, whatever that means, if anything.

On 02/01/2019 08:53, N_Cook wrote:
On 31/12/2018 08:59, N_Cook wrote:
I see GFS has decided on another similar N-pole dipolar arrayment SSW
about 10 Jan 2019




GFS moved it forward to 09 Jan with the balancing/consequential?
diametric cold pool over the UK, whatever that means, if anything.

Shifted to 08 Jan , still with over the UK as the counterbalance or
whatever.