On 10/01/2019 09:07, John Hall wrote:
In message , N_Cook writes
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)


A BBC met bod vague wittering about SSW yesterday evening. GFS has no
trace of any NH SSW out to 15 days. So is the significance a week or 2
after a SSW, , so a "consequence" of the 06 Jan 2019 one?


I've read that it takes typically 2-3 weeks for the effects of a SSW to
make themselves felt down in the troposphere. So yes.

So we could reasonedly expect a firming-up of what GFS currently hints
at 2 weeks out, a Beast-from-the-east-2019, of snow for SE England etc.

On Thursday, January 10, 2019 at 9:46:08 AM UTC, Graham Easterling wrote:
On Thursday, January 10, 2019 at 9:09:22 AM UTC, John Hall wrote:
In message
writes
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)


A BBC met bod vague wittering about SSW yesterday evening. GFS has no
trace of any NH SSW out to 15 days. So is the significance a week or 2
after a SSW, , so a "consequence" of the 06 Jan 2019 one?


I've read that it takes typically 2-3 weeks for the effects of a SSW to
make themselves felt down in the troposphere. So yes.
--
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)

Being a bit cynical, I cant' help noticing that every cold spell we get seems to be down to SSW. If it occurs at the same time or just after, then it's the cause. If it occurs 3 weeks after, it's still the cause due to the reason you describe.

I appreciate it takes time to work down to the troposphere, but it is rapidly become the explanation for all our cold spells (makes a change from SST anomalies or El Nino I suppose) without (seemingly) anyone doing a decent job of explaining a the formation SSW event. What explanations there are being at a very general level, as this thread demonstrates. Similar to geography 'O' level (ox-bow lakes are caused by a river meandering) without any explanation of why rivers meander.

Wait for the next fashionable explanation.

Graham
Penzance

Glorious sunny moring after the 1st air frost (-0.1C) of the winter.

You can't expect one weather type at the surface to follow exactly n days/weeks after another event at a different level in the atmosphere Graham. You know there are many other variables and feedbacks in the mix.
Once the polar vortex weakens and splits, as it did over Christmas/New Year, a chain of events will follow which may lead to colder than average winter weather somewhere at the surface. The lag is thought to be about 2 to 3 weeks, a bit vague I agree, and only 60% of Sudden Stratospheric Warmings lead to unusually cold conditions at the surface.
No one variable leads colder than average winter weather.

Having said that take a look at this and get your longjohns ready.
:-()
http://www.wetterzentrale.de/show_di...05&lid=ENS&bw=

Len
Wembury

On Thursday, January 10, 2019 at 4:10:04 PM UTC, wrote:
On Thursday, January 10, 2019 at 9:46:08 AM UTC, Graham Easterling wrote:
On Thursday, January 10, 2019 at 9:09:22 AM UTC, John Hall wrote:
In message
writes
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)


A BBC met bod vague wittering about SSW yesterday evening. GFS has no
trace of any NH SSW out to 15 days. So is the significance a week or 2
after a SSW, , so a "consequence" of the 06 Jan 2019 one?


I've read that it takes typically 2-3 weeks for the effects of a SSW to
make themselves felt down in the troposphere. So yes.
--
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)

Being a bit cynical, I cant' help noticing that every cold spell we get seems to be down to SSW. If it occurs at the same time or just after, then it's the cause. If it occurs 3 weeks after, it's still the cause due to the reason you describe.

I appreciate it takes time to work down to the troposphere, but it is rapidly become the explanation for all our cold spells (makes a change from SST anomalies or El Nino I suppose) without (seemingly) anyone doing a decent job of explaining a the formation SSW event. What explanations there are being at a very general level, as this thread demonstrates. Similar to geography 'O' level (ox-bow lakes are caused by a river meandering) without any explanation of why rivers meander.

Wait for the next fashionable explanation.

Graham
Penzance


You can't expect one weather type at the surface to follow exactly n days/weeks after another event at a different level in the atmosphere Graham. You know there are many other variables and feedbacks in the mix.

Precisely, that was my point really. People dash out to forecast snow, ice & beasts from the east, on the basis of a process they don't fully understand, which may or may not result in a cold spell anything from a day or 2 to a few weeks hence. If it occurs (which given the vagueness involved is a distinct possibility through chance alone) they all shout "we saw it coming", which is all a bit Daily Express!

Graham
Penzance Sunniest day of the year down here.

In message ,
Graham Easterling writes
Being a bit cynical, I cant' help noticing that every cold spell we get
seems to be down to SSW. If it occurs at the same time or just after,
then it's the cause. If it occurs 3 weeks after, it's still the cause
due to the reason you describe.

There's a useful list of Major SSWs in this article (not quite up to
date):

https://www.earth-syst-sci-data.net/...-9-63-2017.pdf

See Table 2 on page 66. From that it's evident that many weren't
followed by notable cold spells in the UK and, conversely, that many
notable UK cold spells weren't preceded by a SSW.
--
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)

In message , N_Cook
writes
On 10/01/2019 09:07, John Hall wrote:
In message , N_Cook writes
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)


A BBC met bod vague wittering about SSW yesterday evening. GFS has no
trace of any NH SSW out to 15 days. So is the significance a week or 2
after a SSW, , so a "consequence" of the 06 Jan 2019 one?


I've read that it takes typically 2-3 weeks for the effects of a SSW to
make themselves felt down in the troposphere. So yes.

So we could reasonedly expect a firming-up of what GFS currently hints
at 2 weeks out, a Beast-from-the-east-2019, of snow for SE England etc.

It's nowhere near as cut-and-dried as that, as others have commented
(and so have I in another post that I've just made to this thread).
--
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)

John Hall wrote:

In message , N_Cook
writes
On 10/01/2019 09:07, John Hall wrote:
In message , N_Cook
writes
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)


A BBC met bod vague wittering about SSW yesterday evening. GFS
has no trace of any NH SSW out to 15 days. So is the
significance a week or 2 after a SSW, , so a "consequence" of
the 06 Jan 2019 one?


I've read that it takes typically 2-3 weeks for the effects of a
SSW to make themselves felt down in the troposphere. So yes.

So we could reasonedly expect a firming-up of what GFS currently
hints at 2 weeks out, a Beast-from-the-east-2019, of snow for SE
England etc.

It's nowhere near as cut-and-dried as that, as others have commented
(and so have I in another post that I've just made to this thread).


And no doubt there's a lot of 'wishcasting' going on :-)

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

On 10/01/2019 19:46, John Hall wrote:
In message ,
Graham Easterling writes
Being a bit cynical, I cant' help noticing that every cold spell we
get seems to be down to SSW. If it occurs at the same time or just
after, then it's the cause. If it occurs 3 weeks after, it's still the
cause due to the reason you describe.

There's a useful list of Major SSWs in this article (not quite up to date):

https://www.earth-syst-sci-data.net/...-9-63-2017.pdf

See Table 2 on page 66. From that it's evident that many weren't
followed by notable cold spells in the UK and, conversely, that many
notable UK cold spells weren't preceded by a SSW.

Some more recent NH approx SSW central dates, that may or may not fit
their definition.
04 Mar 2016
31 oct 2016
16 Feb 2018
12 Dec 2018
06 Jan 2019

My pc would throw in the towel confronted by a 300GB file.

GFS seems to be firming up , 2 to 3 weeks on from 06 Jan 2019 SSW, in
terms of a few days of snow for southern England and 850HPa temp anomaly.

On Thursday, 10 January 2019 16:40:15 UTC, Graham Easterling wrote:
On Thursday, January 10, 2019 at 4:10:04 PM UTC, wrote:
On Thursday, January 10, 2019 at 9:46:08 AM UTC, Graham Easterling wrote:
On Thursday, January 10, 2019 at 9:09:22 AM UTC, John Hall wrote:
In message
writes
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)


A BBC met bod vague wittering about SSW yesterday evening. GFS has no
trace of any NH SSW out to 15 days. So is the significance a week or 2
after a SSW, , so a "consequence" of the 06 Jan 2019 one?


I've read that it takes typically 2-3 weeks for the effects of a SSW to
make themselves felt down in the troposphere. So yes.
--
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)

Being a bit cynical, I cant' help noticing that every cold spell we get seems to be down to SSW. If it occurs at the same time or just after, then it's the cause. If it occurs 3 weeks after, it's still the cause due to the reason you describe.

I appreciate it takes time to work down to the troposphere, but it is rapidly become the explanation for all our cold spells (makes a change from SST anomalies or El Nino I suppose) without (seemingly) anyone doing a decent job of explaining a the formation SSW event. What explanations there are being at a very general level, as this thread demonstrates. Similar to geography 'O' level (ox-bow lakes are caused by a river meandering) without any explanation of why rivers meander.

Wait for the next fashionable explanation.

Graham
Penzance


You can't expect one weather type at the surface to follow exactly n days/weeks after another event at a different level in the atmosphere Graham. You know there are many other variables and feedbacks in the mix.

Precisely, that was my point really. People dash out to forecast snow, ice & beasts from the east, on the basis of a process they don't fully understand, which may or may not result in a cold spell anything from a day or 2 to a few weeks hence. If it occurs (which given the vagueness involved is a distinct possibility through chance alone) they all shout "we saw it coming", which is all a bit Daily Express!

Graham
Penzance Sunniest day of the year down here.

Oh I have said this so many times. However some *want* snow and will leap on anyone who says they *may* not get it.

I have the scars! It is especially true of SSWs. Some want to believe it will produce snow and cold, but the data do not back this up. It's a 'might'. Even if cold and snow follows a SSW, we still can't be sure about causation, though sometimes the link appears to be clearer than at other times.

A BBC met bod vague wittering about SSW yesterday evening. GFS has no
trace of any NH SSW out to 15 days. So is the significance a week or 2
after a SSW, , so a "consequence" of the 06 Jan 2019 one?


I've read that it takes typically 2-3 weeks for the effects of a SSW to
make themselves felt down in the troposphere. So yes.
--
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)

Being a bit cynical, I cant' help noticing that every cold spell we get seems to be down to SSW. If it occurs at the same time or just after, then it's the cause. If it occurs 3 weeks after, it's still the cause due to the reason you describe.

I appreciate it takes time to work down to the troposphere, but it is rapidly become the explanation for all our cold spells (makes a change from SST anomalies or El Nino I suppose) without (seemingly) anyone doing a decent job of explaining a the formation SSW event. What explanations there are being at a very general level, as this thread demonstrates. Similar to geography 'O' level (ox-bow lakes are caused by a river meandering) without any explanation of why rivers meander.

Wait for the next fashionable explanation.

Graham
Penzance


You can't expect one weather type at the surface to follow exactly n days/weeks after another event at a different level in the atmosphere Graham. You know there are many other variables and feedbacks in the mix.

Precisely, that was my point really. People dash out to forecast snow, ice & beasts from the east, on the basis of a process they don't fully understand, which may or may not result in a cold spell anything from a day or 2 to a few weeks hence. If it occurs (which given the vagueness involved is a distinct possibility through chance alone) they all shout "we saw it coming", which is all a bit Daily Express!

Graham
Penzance Sunniest day of the year down here.

Oh I have said this so many times. However some *want* snow and will leap on anyone who says they *may* not get it.

I have the scars! It is especially true of SSWs. Some want to believe it will produce snow and cold, but the data do not back this up. It's a 'might'. Even if cold and snow follows a SSW, we still can't be sure about causation, though sometimes the link appears to be clearer than at other times.
-------------------------------------------------------------------------
If the Met Office says it is going to happen. It is going to happen.
;-)
https://www.metoffice.gov.uk/news/re...weather-coming

Len
Wembury
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