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

In message
, Neo
writes
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.

To summarise: It's early winter and it's warm therefore it will get
colder.
--
Carlo Marx

That is no how it is mean't to be interpreted.

When I refer to mild vs cold, I am referring to the bias according to
the average. ie colder than average, or milder than average...not
specific numbers which show a cooling trend over time with the
impending winter months.

So for example, with an average daytime MAX of PS 09 to PS 10° C in
Central England for this week, colder would be say PS 05°. But for the
second week of December the daytime average would be say PS 05 to PS
06° C, so colder would be ZERO to PS 02° C...it is relative to the
weeks in question, and is not a definitive figure.


Neo

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

It will be interesting to see if your ideas come to fruition. There is
nothing on the models to suggest this, but models can change
spectacularly in the course of 4 days and to be perfectly honest, I
wouldn't expect them to stay the same as what is being shown at T+300+
either (I don't think we will see any great cold at 6 days though).

I note that you haven't actually said how they will change and what
new synoptic set-up will produce the cold, or how cold it is likely to
get, or at what actual time, apart from sometime in a 10-day period,
we'll see this change. I guess you are keeping your options open on
those. *))

HA HA SUCKER
I KNEW SHREK WOULD REPLY

On 13/11/2011 9:35 PM, Dawlish wrote:
On Nov 13, 4:20 pm, 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

It will be interesting to see if your ideas come to fruition. There is
nothing on the models to suggest this, but models can change
spectacularly in the course of 4 days and to be perfectly honest, I
wouldn't expect them to stay the same as what is being shown at T+300+
either (I don't think we will see any great cold at 6 days though).

I note that you haven't actually said how they will change and what
new synoptic set-up will produce the cold, or how cold it is likely to
get, or at what actual time, apart from sometime in a 10-day period,
we'll see this change. I guess you are keeping your options open on
those. *))

It will be interesting to see if your ideas come to fruition. There is
nothing on the models to suggest this, but models can change
spectacularly in the course of 4 days and to be perfectly honest, I
wouldn't expect them to stay the same as what is being shown at T+300+
either (I don't think we will see any great cold at 6 days though).

I note that you haven't actually said how they will change and what
new synoptic set-up will produce the cold, or how cold it is likely to
get, or at what actual time, apart from sometime in a 10-day period,
we'll see this change. I guess you are keeping your options open on
those. *))

Hi,
Well from the things that I am seeing at the moment, it looks like
high pressure will slowly migrate further E from the E of the UK, with
low pressure starting to the WSW of the UK, then sinking S across
Central and Southern France as another High builds over from the
Greenland area.
This will pull in a due northerly flow, which will bring some
progressively colder air in.

Obviously cold advection over warmer seas will temper the initial
temperature differential, with the usual shallow convective elements
(Up to 500hPa deep) for a short time, before ridging from the NNW will
eradicate all but the smallest of showers from in the NW of the UK.
With the high building over to the N, it will then slowly veer the
wind to the NE for a while. Then the NE and E of the UK will see the
effects.

With the high remaining to the NE, merging with the one further across
the Ukraine, we shall see the (by then) cold continental air move in
from the E, killing off the showers, and maintaining cold temperatures
into W Europe.

At least, this is the scenario that I can see happening over the
coming weeks, however, as with all these sorts of things, it all
depends on the timing.

Our normal Jet stream pattern obviously will go S gradually as a
result, so S Europe should see some poor weather for a time.

Upper atmospheric temperatures are indeed falling away again, but the
pattern seems slightly altered from last year...hence the timing
difficulties.

The flip flopping of the model scenarios is just one symptom of the
upper atmospheric conditions at the moment...they will settle down to
a solution soon enough.

The continental surfaces are cooling close to the UK, hence the cool/
damp conditions along the E of the UK over recent days at very low
levels...signs of the annual winter coldness gradually seeping
in....look at the model forecast skew/TPhi ascents for the E of the
UK over the next 24 hours showing the dropping 950mb temperature. From
PS 10C to PS 03 C in 12 hours from midnight. I have been tracking this
for a day or two.

This low level cooling will of course keep going over the weeks to
come under continental high pressure...so when we do see E winds, they
are going to be colder than now.

Neo

On 13/11/2011 10:40 PM, Neo wrote:


This low level cooling will of course keep going over the weeks to
come under continental high pressure...so when we do see E winds, they
are going to be colder than now.

Neo

whats your winter lrf

On Nov 13, 10:48*pm, The Texican wrote:
On 13/11/2011 10:40 PM, Neo wrote:



This low level cooling will of course keep going over the weeks to
come under continental high pressure...so when we do see E winds, they
are going to be colder than now.

Neo

whats your winter lrf

That is almost impossible to say, despite some claims in here, but my
educated "opinion" is for a cold start to 2012, which may easily
linger into Early March...ask me again one day, it's hard enough
keeping up with the next 2 days to 4 weeks at the moment. I might
forecast, but my expertise is not God like....unlike my ageing
physique!

Neo

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? ;-)

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