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

The models haven't changed, Neo. No colder conditions at the start of
December are on the horizon. The ensembles are actually trending more
towards a continuing Atlantic zonal scenario and the suggested
northerly, then a sinking of the lows into Europe allowing easterlies
to develop is now very unlikely during the first week of December.
Will's snowflake also looks less and less likely with the 06z gfs,
which is ticking upwards, in terms of the ensemble mean temperatures,
at 10 days+. We'll lose the very mild weather, but we are not looking
at below average temperatures at the start of December. Piers must be
chewing on his middle knuckles by now, desperately hoping it will all
change - blizzards on Dec 1/2 look extremely unlikely!

What's happened?

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


Winter does not start until 21 Dec, in the Northern Hemisphere.

"Dawlish" wrote in message
...

On Nov 13, 4:20 pm, Neo wrote:
The models haven't changed, Neo. No colder conditions at the start of
December are on the horizon. The ensembles are actually trending more
towards a continuing Atlantic zonal scenario and the suggested
northerly, then a sinking of the lows into Europe allowing easterlies
to develop is now very unlikely during the first week of December.
Will's snowflake also looks less and less likely with the 06z gfs,
which is ticking upwards, in terms of the ensemble mean temperatures,
at 10 days+. We'll lose the very mild weather, but we are not looking
at below average temperatures at the start of December. Piers must be
chewing on his middle knuckles by now, desperately hoping it will all
change - blizzards on Dec 1/2 look extremely unlikely!

What's happened?

Paul, I detect an element of point-scoring amidst your otherwise reasonable
post? If not, my apologies. However sometimes it does come across that way!

Neo's assessment of Nov 13th now looks highly (no pun intended!) unlikely as
per the synoptic pattern he described. The chance of a Greenland High
Pressure, or any High pressure in or around that location, exerting an
influence in the immediate or medium term does not seem likely. Until I see
some greens (or even light blues) indicating proper height rises over
Greenland I won't be expecting anything of the sort.

12z 21/11 9-panel
http://www.wetterzentrale.de/pics/avnpanel1.gif

Having said that though there is a cooling on the way and the ensembles show
that fairly markedly IMO. Colder conditions for early December certainly
look on the cards, i.e. colder than what we have had with 12-15c temp now
falling to something more normal or even slightly below at times, 7-8c?

Ref. Dublin 12z 21/11 850hpA
http://www.wetterzentrale.de/pics/MT8_Dublin_ens.png

Based on this set of ensembles I think it's more than reasonable for Will to
make the call he has. Snow at his altitude would seem more than possible I
would have though?

As for Piers............don't get me started...........I'm sure there is
some perfectly acceptable excuse or, as is the norm, the weather IS
happening as he forecast. It's just in the wrong place!! ;-)

Joe

In article
,
MahFL writes:
To summarise: It's early winter and it's warm therefore it will get
colder.
--
Carlo Marx


Winter does not start until 21 Dec, in the Northern Hemisphere.

For meteorological purposes, the months of December, January and
February are conventionally taken as winter. There seems no good reason
from a weather point of view why the season should start at the Winter
Solstice, since the first three weeks of December are on average a fair
bit colder than the first three weeks of March.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw

On 21/11/2011 18:59, John Hall wrote:
For meteorological purposes, the months of December, January and
February are conventionally taken as winter. There seems no good reason
from a weather point of view why the season should start at the Winter
Solstice, since the first three weeks of December are on average a fair
bit colder than the first three weeks of March.

That's because Mah is using the astronomical seasons (common in the USA
I believe?), whilst we have a tendency to use the standard
meteorological seasons of DJF, MAM, JJA, SON.

These sort of fit reasonably well and is convenient but looking at how
nature responds to the seasons around here, I regard mid-February
onwards as spring until mid-May, then summer until mid-September. Autumn
seems the shortest season with it being pretty much winter-like from
mid-November (this month has been an exception).
--
Nick G
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk

On Nov 21, 6:43*pm, "Joe Whyte" wrote:
"Dawlish" *wrote in message

...

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

The models haven't changed, Neo. No colder conditions at the start of
December are on the horizon. The ensembles are actually trending more
towards a continuing Atlantic zonal scenario and the suggested
northerly, then a sinking of the lows into Europe allowing easterlies
to develop is now very unlikely during the first week of December.
Will's snowflake also looks less and less likely with the 06z gfs,
which is ticking upwards, in terms of the ensemble mean temperatures,
at 10 days+. We'll lose the very mild weather, but we are not looking
at below average temperatures at the start of December. Piers must be
chewing on his middle knuckles by now, desperately hoping it will all
change - blizzards on Dec 1/2 look extremely unlikely!

What's happened?

Paul, I detect an element of point-scoring amidst your otherwise reasonable
post? If not, my apologies. However sometimes it does come across that way!

Neo's assessment of Nov 13th now looks highly (no pun intended!) unlikely as
per the synoptic pattern he described. The chance of a Greenland High
Pressure, or any High pressure in or around that location, exerting an
influence in the immediate or medium term does not seem likely. Until I see
some greens (or even light blues) indicating proper height rises over
Greenland I won't be expecting anything of the sort.

12z 21/11 9-panelhttp://www.wetterzentrale.de/pics/avnpanel1.gif

Having said that though there is a cooling on the way and the ensembles show
that fairly markedly IMO. Colder conditions for early December certainly
look on the cards, i.e. colder than what we have had with 12-15c temp now
falling to something more normal or even slightly below at times, 7-8c?

Ref. Dublin 12z 21/11 850hpAhttp://www.wetterzentrale.de/pics/MT8_Dublin_ens.png

Based on this set of ensembles I think it's more than reasonable for Will to
make the call he has. Snow at his altitude would seem more than possible I
would have though?

As for Piers............don't get me started...........I'm sure there is
some perfectly acceptable excuse or, as is the norm, the weather IS
happening as he forecast. It's just in the wrong place!! *;-)

Joe

Your apologies are accepted! *)) It's not point scoring, I'm just
wondering where people go when they make forecasts that don't actually
appear to be achieving the outcomes they were expecting........

You can be sure that Piers' forecast will be correct............when
any analysis of it appears on his website! It could still happen, of
course, it's not the start of December yet, but there will be others
who are also chewing their fingernails about the current model output
after their forecasts of cold at the start of December too.