Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png

On 29/12/2016 13:57, Alan [Guildford] wrote:
Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png


my browser does not show anything remarkable.
Are you referring to the apparent closely spaced contraflow jetstreams
over the full width of the north Atlantic with a spun up low between
them GFS+300 to +330hr ?

On 29/12/2016 13:57, Alan [Guildford] wrote:
Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png



I assume the dot-chain isotherms there, are for 500HPa

On Thu, 29 Dec 2016 14:34:59 +0000, N_Cook wrote:

On 29/12/2016 13:57, Alan [Guildford] wrote:
Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png


my browser does not show anything remarkable.
Are you referring to the apparent closely spaced contraflow jetstreams
over the full width of the north Atlantic with a spun up low between
them GFS+300 to +330hr ?

6 am run has the 850hPa temperature below -10C over the entire British
Isles (currently at T+348) and Central England maximum 2m temperature
at -5C. It will soon change, of course.

Having said that, there is a certain degree of consistency between
models and runs as to the cold northerly plunge at the end of next
week - 2 of 3 of the main models at that range suggest that it may
hang around for a while, so that's definitely one to watch.

--
Dave
Fareham (W)

On Thursday, 29 December 2016 14:58:52 UTC, N_Cook wrote:
On 29/12/2016 13:57, Alan [Guildford] wrote:
Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png



I assume the dot-chain isotherms there, are for 500HPa

Yes so cold upper air with 500mb-1000mb thickness circa 512dam for South East England. The low would also bring significant dry snow for South East England. Highly Unlikely but nevertheless interesting set of charts for today's 6Z GFS at T+324

Alan [Guildford] wrote:

On Thursday, 29 December 2016 14:58:52 UTC, N_Cook wrote:
On 29/12/2016 13:57, Alan [Guildford] wrote:
Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png



I assume the dot-chain isotherms there, are for 500HPa

Yes so cold upper air with 500mb-1000mb thickness circa 512dam for South East
England. The low would also bring significant dry snow for South East
England. Highly Unlikely but nevertheless interesting set of charts for
today's 6Z GFS at T+324

.......but that run is an extreme cold outlier amongst the ensembles at 06z. To
take any notice of it would be very unwise.

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

On Thursday, 29 December 2016 15:59:26 UTC, Norman Lynagh wrote:
Alan [Guildford] wrote:

On Thursday, 29 December 2016 14:58:52 UTC, N_Cook wrote:
On 29/12/2016 13:57, Alan [Guildford] wrote:
Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png



I assume the dot-chain isotherms there, are for 500HPa

Yes so cold upper air with 500mb-1000mb thickness circa 512dam for South East
England. The low would also bring significant dry snow for South East
England. Highly Unlikely but nevertheless interesting set of charts for
today's 6Z GFS at T+324

......but that run is an extreme cold outlier amongst the ensembles at 06z. To
take any notice of it would be very unwise.

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

Indeed

In message , Norman Lynagh
writes
Alan [Guildford] wrote:

On Thursday, 29 December 2016 14:58:52 UTC, N_Cook wrote:
On 29/12/2016 13:57, Alan [Guildford] wrote:
Obviously out in fantasy land but something to dream about


http://www.wetterzentrale.de/maps/GFSOPUK06_324_1.png



I assume the dot-chain isotherms there, are for 500HPa

Yes so cold upper air with 500mb-1000mb thickness circa 512dam for South East
England. The low would also bring significant dry snow for South East
England. Highly Unlikely but nevertheless interesting set of charts for
today's 6Z GFS at T+324

......but that run is an extreme cold outlier amongst the ensembles at 06z. To
take any notice of it would be very unwise.


Of course it would be unwise to take much notice. That said, the
ensemble mean is looking quite chilly from about the 6th January
onwards, with some other ensemble members being little warmer than the
operational.
--
John Hall
"One can certainly imagine the myriad of uses
for a hand-held iguana maker"
Hobbes (the tiger, not the philosopher!)

In message , John Hall
writes
In message , Norman Lynagh
writes

......but that run is an extreme cold outlier amongst the ensembles at 06z. To
take any notice of it would be very unwise.


Of course it would be unwise to take much notice. That said, the
ensemble mean is looking quite chilly from about the 6th January
onwards, with some other ensemble members being little warmer than the
operational.

The 12Z GFS operational is now out. Somewhat to my surprise, it keeps a
pronounced cold spell, albeit not so extreme or long-lasting as in the
06Z run. It will be interesting to see what the 12Z ECMWF comes up with
when it becomes available, though the cold spell - if it should happen -
begins pretty much at the end of the 10 day period that ECMWF forecasts
for.
--
John Hall
"One can certainly imagine the myriad of uses
for a hand-held iguana maker"
Hobbes (the tiger, not the philosopher!)

On 29/12/2016 17:02, John Hall wrote:
In message , John Hall
writes
In message , Norman Lynagh
writes

......but that run is an extreme cold outlier amongst the ensembles
at 06z. To
take any notice of it would be very unwise.


Of course it would be unwise to take much notice. That said, the
ensemble mean is looking quite chilly from about the 6th January
onwards, with some other ensemble members being little warmer than the
operational.

The 12Z GFS operational is now out. Somewhat to my surprise, it keeps a
pronounced cold spell, albeit not so extreme or long-lasting as in the
06Z run. It will be interesting to see what the 12Z ECMWF comes up with
when it becomes available, though the cold spell - if it should happen -
begins pretty much at the end of the 10 day period that ECMWF forecasts
for.
-------------------------------------------------------------------------------
We should probably be looking at things closer to now. I wouldn't be
surprised to see a little snow on the back edge of the cold front as it
moves through in the early hours of this Monday. Won't hang around but a
couple of coldish days. Then I would imagine most of the first half of
January will be at least on the cold side with a fair amount of
blocking. Where the various HP's end up of course will be critical to
the extent of any cold or snow but I think I am prepared to say "at
least it won't be mild" ;-) A few days like today wouldn't be bad either!
Dave

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