On Nov 14, 1:42*pm, Neo wrote:
On Nov 14, 12:19*pm, Dave Cornwell wrote:

Neo wrote:

* A few things are coming together now that will seem to aid

the cooling process in W Europe over the coming days/weeks.

-------------------

Winter? ;-)

No, positioning of upper air features/jet trajectories, changes in
stability, cloud distribution, proximity/arrival of drier air,
modifying of slow moving air, origins of air masses.....of course
winter makes it cooler, but with respect to average winter
temperatures, air cools differently if it has a strong SSW Tropical
origin than it would with a slow or moderate Polar or Polar
Continental origin.

Go and read basic meteorology texts about airmass theory and
modification of airmasses in different seasons. Then read up about
upper air theory and the broad scale distribution and propagation of
jet streams and upper atmospheric thermodynamics.
It is all very interesting, we are talking real weather here, not
climate.

Neo

----------------------------------------------------------------------------------------------------
It is all about the total (substantial) derivative in the model
equations.
Total cooling = that advected + the in situ cooling.
The advected cooling is the dominant term. It's chilly up north.
Cloudiness is rather important. Solar warming is small in winter, but
longwave cooling at the surface important for land surface temps.

Models are not especially good with the cloud radiative properties
having to cope with horizontal inhomogeneity, multiple layers, cloud
overlap...

One could say that it's the flipping clouds that make the models flip.
:-)

Len Wood
Wembury, SW Devon, 83m asl

On Nov 14, 1:42*pm, Neo wrote:
On Nov 14, 12:19*pm, Dave Cornwell wrote:

Neo wrote:

* A few things are coming together now that will seem to aid

the cooling process in W Europe over the coming days/weeks.

-------------------

Winter? ;-)

No, positioning of upper air features/jet trajectories, changes in
stability, cloud distribution, proximity/arrival of drier air,
modifying of slow moving air, origins of air masses.....of course
winter makes it cooler, but with respect to average winter
temperatures, air cools differently if it has a strong SSW Tropical
origin than it would with a slow or moderate Polar or Polar
Continental origin.

Go and read basic meteorology texts about airmass theory and
modification of airmasses in different seasons. Then read up about
upper air theory and the broad scale distribution and propagation of
jet streams and upper atmospheric thermodynamics.
It is all very interesting, we are talking real weather here, not
climate.

Neo

Nothing showing yet......

On 14/11/11 21:05, Dawlish wrote:
On Nov 14, 1:42 pm, wrote:
On Nov 14, 12:19 pm, Dave wrote:

Neo wrote:

A few things are coming together now that will seem to aid

the cooling process in W Europe over the coming days/weeks.

-------------------

Winter? ;-)

No, positioning of upper air features/jet trajectories, changes in
stability, cloud distribution, proximity/arrival of drier air,
modifying of slow moving air, origins of air masses.....of course
winter makes it cooler, but with respect to average winter
temperatures, air cools differently if it has a strong SSW Tropical
origin than it would with a slow or moderate Polar or Polar
Continental origin.

Go and read basic meteorology texts about airmass theory and
modification of airmasses in different seasons. Then read up about
upper air theory and the broad scale distribution and propagation of
jet streams and upper atmospheric thermodynamics.
It is all very interesting, we are talking real weather here, not
climate.

Neo

Nothing showing yet......

I will be interested to see just how long this mild weather continues
for, the temperatures are bound to drop significantly at some point,
aren't they?

I'm hoping when they do, it will put an end to the ongoing caterpillar
infestation on my brocolli.

On Nov 14, 11:42*pm, Adam Lea wrote:
On 14/11/11 21:05, Dawlish wrote:





On Nov 14, 1:42 pm, *wrote:
On Nov 14, 12:19 pm, Dave *wrote:

Neo wrote:

* *A few things are coming together now that will seem to aid

the cooling process in W Europe over the coming days/weeks.

-------------------

Winter? ;-)

No, positioning of upper air features/jet trajectories, changes in
stability, cloud distribution, proximity/arrival of drier air,
modifying of slow moving air, origins of air masses.....of course
winter makes it cooler, but with respect to average winter
temperatures, air cools differently if it has a strong SSW Tropical
origin than it would with a slow or moderate Polar or Polar
Continental origin.

Go and read basic meteorology texts about airmass theory and
modification of airmasses in different seasons. Then read up about
upper air theory and the broad scale distribution and propagation of
jet streams and upper atmospheric thermodynamics.
It is all very interesting, we are talking real weather here, not
climate.

Neo

Nothing showing yet......

I will be interested to see just how long this mild weather continues
for, the temperatures are bound to drop significantly at some point,
aren't they?

I'm hoping when they do, it will put an end to the ongoing caterpillar
infestation on my brocolli.- Hide quoted text -

- Show quoted text -

Certain to. They are at close to record levels for Nov. That could
explain why now is a good time to forecast UK cooling to start,
because of whichever factor one decides is the reason, apart from the
fact that winter is coming and emperatures won't stay as high as they
have been!

PS You're still harvesting Broccoli Adam?

On 15/11/11 06:53, Dawlish wrote:
On Nov 14, 11:42 pm, Adam wrote:
On 14/11/11 21:05, Dawlish wrote:





On Nov 14, 1:42 pm, wrote:
On Nov 14, 12:19 pm, Dave wrote:

Neo wrote:

A few things are coming together now that will seem to aid

the cooling process in W Europe over the coming days/weeks.

-------------------

Winter? ;-)

No, positioning of upper air features/jet trajectories, changes in
stability, cloud distribution, proximity/arrival of drier air,
modifying of slow moving air, origins of air masses.....of course
winter makes it cooler, but with respect to average winter
temperatures, air cools differently if it has a strong SSW Tropical
origin than it would with a slow or moderate Polar or Polar
Continental origin.

Go and read basic meteorology texts about airmass theory and
modification of airmasses in different seasons. Then read up about
upper air theory and the broad scale distribution and propagation of
jet streams and upper atmospheric thermodynamics.
It is all very interesting, we are talking real weather here, not
climate.

Neo

Nothing showing yet......

I will be interested to see just how long this mild weather continues
for, the temperatures are bound to drop significantly at some point,
aren't they?

I'm hoping when they do, it will put an end to the ongoing caterpillar
infestation on my brocolli.- Hide quoted text -

- Show quoted text -

Certain to. They are at close to record levels for Nov. That could
explain why now is a good time to forecast UK cooling to start,
because of whichever factor one decides is the reason, apart from the
fact that winter is coming and emperatures won't stay as high as they
have been!

PS You're still harvesting Broccoli Adam?

I started growing Broccoli this year so it has been producing copious
amounts of leaves this season but no florets. I have been informed that
they will produce a crop next year, however it is more a case of whether
they will survive that long, as some of them look like a plague of
locusts has gone through.

rant
Every single time I try to grow my own food it either gets destroyed by
unusual weather conditions or a major pest infestation.
/rant

On Nov 13, 4:20*pm, Neo wrote:
Keep an eye on them. The intrinsic probabilistic data have recently
shown signs of being flipped from the current solution (ie not cold),
just as they were tilted towards a milder outlook a few days ago...Now
thay are looking as if they could re-flip in the 6 to 15 day period
outlook. A few things are coming together now that will seem to aid
the cooling process in W Europe over the coming days/weeks.

The models are such that this sort of situation becomes mathematically
unstable with just the slightest change to just 1 or 2 aspects of the
variable dataset. The deterministic output will consequently flip-flop
for a while (ie now), before the true scope of the forecast becomes
clearer mathematically (more constant model output/outcomes). This
time span seems to be in the next 6 to 15 day period.

Neo

I kept an eye on them. Nothing extra-specially cold 3 days on, Neo;
just the possibility of the high pressure that looked like it might
settle to our S/SE, now looking like it may settle over the UK. Just
looks like a slow and steady descent into early winter, with a little
cooler temperatures, but with them staying pretty average really and
the possibility of some frog and fost if the skies clear. 8))

See if the model agreement about the position of the high pressure
lasts to tonight.

On Nov 16, 8:30*am, Dawlish wrote:
On Nov 13, 4:20*pm, Neo wrote:

Keep an eye on them. The intrinsic probabilistic data have recently
shown signs of being flipped from the current solution (ie not cold),
just as they were tilted towards a milder outlook a few days ago...Now
thay are looking as if they could re-flip in the 6 to 15 day period
outlook. A few things are coming together now that will seem to aid
the cooling process in W Europe over the coming days/weeks.

The models are such that this sort of situation becomes mathematically
unstable with just the slightest change to just 1 or 2 aspects of the
variable dataset. The deterministic output will consequently flip-flop
for a while (ie now), before the true scope of the forecast becomes
clearer mathematically (more constant model output/outcomes). This
time span seems to be in the next 6 to 15 day period.

Neo

I kept an eye on them. Nothing extra-specially cold 3 days on, Neo;
just the possibility of the high pressure that looked like it might
settle to our S/SE, now looking like it may settle over the UK. Just
looks like a slow and steady descent into early winter, with a little
cooler temperatures, but with them staying pretty average really and
the possibility of some frog and fost if the skies clear. 8))

See if the model agreement about the position of the high pressure
lasts to tonight.

Just as an addition to the last comment; neither the gfs 00z. nor the
ECM 12z from yesterday back the establishment of a static high
pressure over the UK at 10 days and we may well see the models change
back to a more zonal outlook during today. There's nothing
particularly cold about the ensemble means of either model.

On Nov 16, 8:37*am, Dawlish wrote:
On Nov 16, 8:30*am, Dawlish wrote:





On Nov 13, 4:20*pm, Neo wrote:

Keep an eye on them. The intrinsic probabilistic data have recently
shown signs of being flipped from the current solution (ie not cold),
just as they were tilted towards a milder outlook a few days ago...Now
thay are looking as if they could re-flip in the 6 to 15 day period
outlook. A few things are coming together now that will seem to aid
the cooling process in W Europe over the coming days/weeks.

The models are such that this sort of situation becomes mathematically
unstable with just the slightest change to just 1 or 2 aspects of the
variable dataset. The deterministic output will consequently flip-flop
for a while (ie now), before the true scope of the forecast becomes
clearer mathematically (more constant model output/outcomes). This
time span seems to be in the next 6 to 15 day period.

Neo

I kept an eye on them. Nothing extra-specially cold 3 days on, Neo;
just the possibility of the high pressure that looked like it might
settle to our S/SE, now looking like it may settle over the UK. Just
looks like a slow and steady descent into early winter, with a little
cooler temperatures, but with them staying pretty average really and
the possibility of some frog and fost if the skies clear. 8))

See if the model agreement about the position of the high pressure
lasts to tonight.

Just as an addition to the last comment; neither the gfs 00z. nor the
ECM 12z from yesterday back the establishment of a static high
pressure over the UK at 10 days and we may well see the models change
back to a more zonal outlook during today. There's nothing
particularly cold about the ensemble means of either model.- Hide quoted text -

- Show quoted text -

And, as if on cue, the 06z does exactly that and the operational shows
up as a big spikey, dry outlier! The jet is forcast to lie to the
north of the UK at 10 days and not to the south.

http://www.wetterzentrale.de/pics/Rtavn24014.png

I don't see anything in the mnodel output that suggests a major change
to below average temperature conditions - yet. Neo?

On Nov 16, 8:37*am, Dawlish wrote:
On Nov 16, 8:30*am, Dawlish wrote:



On Nov 13, 4:20*pm, Neo wrote:

Keep an eye on them. The intrinsic probabilistic data have recently
shown signs of being flipped from the current solution (ie not cold),
just as they were tilted towards a milder outlook a few days ago...Now
thay are looking as if they could re-flip in the 6 to 15 day period
outlook. A few things are coming together now that will seem to aid
the cooling process in W Europe over the coming days/weeks.

The models are such that this sort of situation becomes mathematically
unstable with just the slightest change to just 1 or 2 aspects of the
variable dataset. The deterministic output will consequently flip-flop
for a while (ie now), before the true scope of the forecast becomes
clearer mathematically (more constant model output/outcomes). This
time span seems to be in the next 6 to 15 day period.

Neo

I kept an eye on them. Nothing extra-specially cold 3 days on, Neo;
just the possibility of the high pressure that looked like it might
settle to our S/SE, now looking like it may settle over the UK. Just
looks like a slow and steady descent into early winter, with a little
cooler temperatures, but with them staying pretty average really and
the possibility of some frog and fost if the skies clear. 8))

See if the model agreement about the position of the high pressure
lasts to tonight.

Just as an addition to the last comment; neither the gfs 00z. nor the
ECM 12z from yesterday back the establishment of a static high
pressure over the UK at 10 days and we may well see the models change
back to a more zonal outlook during today. There's nothing
particularly cold about the ensemble means of either model.


Hi Dawlish,

What is your source of the interpreted information?
Or do you derive that from looking at some of the publicly available
output?
Do you work at a large glass building in Devon, hence your screen
name?

Something I have seen in the model outputs (Might have been be an
outlier a few days ago, but a few more than one now suggest this)
suggests something changing on or around the end of Nov/early Dec.
It suggests a cold NNW incursion as low pressure/cold front sinks SE
from a temporary mobile W scenario. This followed by rising pressure
across the far N of the UK, giving some N, then NE winds. The high
then becomes slow moving just to the N of the UK, and may even link
with the high over towards Finland eventually.
The info would suggest normal temps just ahead of this event, with any
rainfall reverting to snow on scottish mountains, followed by a cold
regime, especially for the N and E of the UK.
Low pressure begins to affect the Med area/S Europe, with unsettled
conditions for many down there.

Looks like maybe we will see the changes take effect as December draws
in. Can't be any worse that last year, whatever happens.

I also wonder if the upper atmospheric cooling might be behind some
models hinting at this...as not all models incorporate anything too
much above the Jet levels in their longer term variables...it is still
early days in that area of research even now,

Just a thought.

Cheers

Neo

On Nov 16, 1:01*pm, Neo wrote:
On Nov 16, 8:37*am, Dawlish wrote:





On Nov 16, 8:30*am, Dawlish wrote:

On Nov 13, 4:20*pm, Neo wrote:

Keep an eye on them. The intrinsic probabilistic data have recently
shown signs of being flipped from the current solution (ie not cold),
just as they were tilted towards a milder outlook a few days ago...Now
thay are looking as if they could re-flip in the 6 to 15 day period
outlook. A few things are coming together now that will seem to aid
the cooling process in W Europe over the coming days/weeks.

The models are such that this sort of situation becomes mathematically
unstable with just the slightest change to just 1 or 2 aspects of the
variable dataset. The deterministic output will consequently flip-flop
for a while (ie now), before the true scope of the forecast becomes
clearer mathematically (more constant model output/outcomes). This
time span seems to be in the next 6 to 15 day period.

Neo

I kept an eye on them. Nothing extra-specially cold 3 days on, Neo;
just the possibility of the high pressure that looked like it might
settle to our S/SE, now looking like it may settle over the UK. Just
looks like a slow and steady descent into early winter, with a little
cooler temperatures, but with them staying pretty average really and
the possibility of some frog and fost if the skies clear. 8))

See if the model agreement about the position of the high pressure
lasts to tonight.

Just as an addition to the last comment; neither the gfs 00z. nor the
ECM 12z from yesterday back the establishment of a static high
pressure over the UK at 10 days and we may well see the models change
back to a more zonal outlook during today. There's nothing
particularly cold about the ensemble means of either model.

Hi Dawlish,

What is your source of the interpreted information?
Or do you derive that from looking at some of the publicly available
output?
Do you work at a large glass building in Devon, hence your screen
name?

Something I have seen in the model outputs (Might have been be an
outlier a few days ago, but a few more than one now suggest this)
suggests something changing on or around the end of Nov/early Dec.
It suggests a cold NNW incursion as low pressure/cold front sinks SE
from a temporary mobile W scenario. This followed by rising pressure
across the far N of the UK, giving some N, then NE winds. The high
then becomes slow moving just to the N of the UK, and may even link
with the high over towards Finland eventually.
The info would suggest normal temps just ahead of this event, with any
rainfall reverting to snow on scottish mountains, followed by a cold
regime, especially for the N and E of the UK.
Low pressure begins to affect the Med area/S Europe, with unsettled
conditions for many down there.

Looks like maybe we will see the changes take effect as December draws
in. Can't be any worse that last year, whatever happens.

I also wonder if the upper atmospheric cooling might be behind some
models hinting at this...as not all models incorporate anything too
much above the Jet levels in their longer term variables...it is still
early days in that area of research even now,

Just a thought.

Cheers

Neo- Hide quoted text -

- Show quoted text -

I agree the models could always change. Indeed, at 2 weeks, the odds
are they probably will. Nothing showing at present however, that I can
see and it certainly didn't change in yout initial 3/4 day suggested
period. I see you are now suggesting the end of November. Are you
trying to look in the 10-16 day period here on the gfs, or do have
access to some non-publically avainlable data. If so. What is it?

There appears to be nothing unusual happening in the stratosphere.

http://wekuw.met.fu-berlin.de/~Aktue...w/wdiag/ts.php

Recent research suggests that SSW events may influence NH weather. I'm
not aware of reearch that shows that stratospheric cooling causes any
changes at surface levels, but I'd be interested to see a link.