Charts that would have been very nice in July! (but will be very
welcome in 10 days time too!)

http://www.wetterzentrale.de/pics/Rtavn2402.png

Some nice September weather possibly on the cards, starting in the
second week of Sept. Both the gfs and the ECM are in agreement. I
won't take much more persuading that it is likely to happen.

On Aug 30, 9:22*am, Dawlish wrote:
Charts that would have been very nice in July! (but will be very
welcome in 10 days time too!)

http://www.wetterzentrale.de/pics/Rtavn2402.png

Some nice September weather possibly on the cards, starting in the
second week of Sept. Both the gfs and the ECM are in agreement. I
won't take much more persuading that it is likely to happen.

Met Office suggesting settled conditions for that week, but for the
south only. I guess there's some disagreement how far north the high
will get: the MetO would appear to favour a continuation of the
current WSW spell, anticyclonic in the south - which would normally be
absolutely fine if only it wasn't for that damned cold pool of water
in the Atlantic!

Nick

On Aug 30, 9:58*am, Nick wrote:
On Aug 30, 9:22*am, Dawlish wrote:

Charts that would have been very nice in July! (but will be very
welcome in 10 days time too!)

http://www.wetterzentrale.de/pics/Rtavn2402.png

Some nice September weather possibly on the cards, starting in the
second week of Sept. Both the gfs and the ECM are in agreement. I
won't take much more persuading that it is likely to happen.

Met Office suggesting settled conditions for that week, but for the
south only. I guess there's some disagreement how far north the high
will get: the MetO would appear to favour a continuation of the
current WSW spell, anticyclonic in the south - which would normally be
absolutely fine if only it wasn't for that damned cold pool of water
in the Atlantic!

Nick

Hi Nick,

Your point about the south's weather likely to be better than the
north's is a good one. The MetO's present summary shows that, but is
actually is very ambiguous about next week in the south:

"UK Outlook for Friday 4 Sep 2009 to Sunday 13 Sep 2009:
Sunshine and showers on Friday, and perhaps longer periods of rain in
the north and east. Showers ease in the south with many parts dry on
Saturday, but remaining unsettled in the north. Windy at first across
the UK, especially in the north, but winds ease in England and Wales
during the day. **Likely to be less unsettled in the south of the UK
for a time, with more in the way of drier, brighter weather but still
with a chance of showers or rain, especially later in the period**.
The north likely to stay unsettled with rain and strong winds at
times. Temperatures below normal at first, with some cool nights
expected, but recovering to around normal by the end of the period,
**possibly becoming warm in the southeast**.

Updated: 1256 on Sun 30 Aug 2009"

Mind you, actually trying to tease out any detail from this is very
difficult. This is a forecast for a 10-day inclusive period, squeezed
into 120 words! Instead of doing the crossword, I reckon the
forecasters have fun with the skill of precis in their tea breaks
*)). Its brevity shows that it is not given any real importance and
the MetO never returns to this forecast to attempt any judgement of
its accuracy. They know the difficulties of forecasting at any
distance above 5-7 days.

There's enough consistency in the gfs and enough agreement with the
ECM, for me to forecast, with 75% confidence, dry and settled
conditions over the south of the UK in 10 days time, at T240. Temps
will be above the September daytime average. The NW won't be faring as
well and will be plagued by fronts, giving much more unsettled
conditions.

I reckon next week could be a good one for a short break on the south
coast. Still "coulds". Nothing certain, but gamble on these forecasts
and I promise you that you'll come out winning significantly more
times than you lose!

On Aug 31, 9:19*am, Dawlish wrote:
On Aug 30, 9:58*am, Nick wrote:





On Aug 30, 9:22*am, Dawlish wrote:

Charts that would have been very nice in July! (but will be very
welcome in 10 days time too!)

http://www.wetterzentrale.de/pics/Rtavn2402.png

Some nice September weather possibly on the cards, starting in the
second week of Sept. Both the gfs and the ECM are in agreement. I
won't take much more persuading that it is likely to happen.

Met Office suggesting settled conditions for that week, but for the
south only. I guess there's some disagreement how far north the high
will get: the MetO would appear to favour a continuation of the
current WSW spell, anticyclonic in the south - which would normally be
absolutely fine if only it wasn't for that damned cold pool of water
in the Atlantic!

Nick

Hi Nick,

Your point about the south's weather likely to be better than the
north's is a good one. The MetO's present summary shows that, but is
actually is very ambiguous about next week in the south:

"UK Outlook for Friday 4 Sep 2009 to Sunday 13 Sep 2009:
Sunshine and showers on Friday, and perhaps longer periods of rain in
the north and east. Showers ease in the south with many parts dry on
Saturday, but remaining unsettled in the north. Windy at first across
the UK, especially in the north, but winds ease in England and Wales
during the day. **Likely to be less unsettled in the south of the UK
for a time, with more in the way of drier, brighter weather but still
with a chance of showers or rain, especially later in the period**.
The north likely to stay unsettled with rain and strong winds at
times. Temperatures below normal at first, with some cool nights
expected, but recovering to around normal by the end of the period,
**possibly becoming warm in the southeast**.

Updated: 1256 on Sun 30 Aug 2009"

Mind you, actually trying to tease out any detail from this is very
difficult. This is a forecast for a 10-day inclusive period, squeezed
into 120 words! Instead of doing the crossword, I reckon the
forecasters have fun with the skill of precis in their tea breaks
*)). Its brevity shows that it is not given any real importance and
the MetO never returns to this forecast to attempt any judgement of
its accuracy. They know the difficulties of forecasting at any
distance above 5-7 days.

There's enough consistency in the gfs and enough agreement with the
ECM, for me to forecast, with 75% confidence, dry and settled
conditions over the south of the UK in 10 days time, at T240. Temps
will be above the September daytime average. The NW won't be faring as
well and will be plagued by fronts, giving much more unsettled
conditions.

I reckon next week could be a good one for a short break on the south
coast. Still "coulds". Nothing certain, but gamble on these forecasts
and I promise you that you'll come out winning significantly more
times than you lose!- Hide quoted text -

- Show quoted text -

36 hours on and still looking good for a settled and warmer period of
weather next week, for England, at least. Good agreement between the
ECM and gfs. The MetO are coming round to the idea, but won't fully
commit themselves on today's 6-15 day update. I don't really blame
them. It's very easy to make mistakes forecasting at 10 days.

http://www.metoffice.gov.uk/weather/...t_weather.html

On Tue, 1 Sep 2009 at 12:25:43, Dawlish wrote in
uk.sci.weather :

36 hours on and still looking good for a settled and warmer period of
weather next week, for England, at least. Good agreement between the
ECM and gfs. The MetO are coming round to the idea, but won't fully
commit themselves on today's 6-15 day update. I don't really blame
them. It's very easy to make mistakes forecasting at 10 days.

http://www.metoffice.gov.uk/weather/...t_weather.html

If only that set-up would wait 3 months...
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)

"Paul Hyett" wrote in message
...
On Tue, 1 Sep 2009 at 12:25:43, Dawlish wrote in
uk.sci.weather :

36 hours on and still looking good for a settled and warmer period of
weather next week, for England, at least. Good agreement between the
ECM and gfs. The MetO are coming round to the idea, but won't fully
commit themselves on today's 6-15 day update. I don't really blame
them. It's very easy to make mistakes forecasting at 10 days.

http://www.metoffice.gov.uk/weather/...t_weather.html

If only that set-up would wait 3 months...
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)

Any forecast beyond 5 days needs to be taken with a huge pinch of salt at
this time of year, despite any apparent consistency. Hurricanes can develop
quickly and unexpectedly and have great potential for altering the strength
of jets and their orientation as they become extra-tropical. Also there is
at least one upper trough disruption before the forecast high pressure
period and models do not handle trough disruptions well. Confidence in an
anticyclone at this stage has to 50% at most I'd say.

Will
--

On Aug 31, 9:19*am, Dawlish wrote:
On Aug 30, 9:58*am, Nick wrote:

There's enough consistency in the gfs and enough agreement with the
ECM, for me to forecast, with 75% confidence, dry and settled
conditions over the south of the UK in 10 days time, at T240. Temps
will be above the September daytime average. The NW won't be faring
as
well and will be plagued by fronts, giving much more unsettled
conditions.

You've just got to ask yourself; "Why couldn't this have happened in
July/August"! However I'll take this in September too. Just my kind of
weather. Dry settled and warm in the daytime sunshine.

The gfs spotted this pattern change first and the ECM followed soon
after. The consistency the gfs showed about the change and the
agreement from the ECM prompted the forecast and it was a good one.
There are some fronts around the NW limb of the high and there is some
light rain over the far NW of Scotland, but the rest of the country
should enjoy a fine and a dry day, after some early mist and fog in a
few areas. There's NE flow across the South producing breezy weather
and Will did correctly mention that would happen, but the overall
picture is dry and settled. Overall, that's 72 forecasts at 10 days
and 54 correct; an outcome percentage success rate of 76%.

The fine weather should last for a while too, as I've implied with my
similar forecast for 3 days time, but a change may be a-coming for 10
days time - the ECM is leading that possibility but the gfs has not
shown enough consistency yet; some runs having dallied with a
continuance of the anticyclonic weather whilst others have shown a
return to Atlantic weather over the last 48 hours. Another couple of
gfs runs showing windy and wet weather at T240 and I'd be convinced
this blocking pattern won't last to the end of the third week of
September.

Time to enjoy some quintessential Autumnal weather. 8))

On Sep 10, 7:50*am, Dawlish wrote:
On Aug 31, 9:19*am, Dawlish wrote: On Aug 30, 9:58*am, Nick wrote:

Overall, that's 72 forecasts at 10 days and 54 correct; an outcome percentage success rate of 76%.

Sorry guys and gals, that's a mistake. I'd not added on this one!
55/72 and 76%.

On 10 Sep, 08:17, Dawlish wrote:
On Sep 10, 7:50*am, Dawlish wrote:

On Aug 31, 9:19*am, Dawlish wrote: On Aug 30, 9:58*am, Nick wrote:
Overall, that's 72 forecasts at 10 days and 54 correct; an outcome percentage success rate of 76%.

Sorry guys and gals, that's a mistake. I'd not added on this one!
55/72 and 76%.

Interesting - is this 55 times out of 72 consecutive days' forecasts?

Richard

On Sep 10, 7:50*am, Dawlish wrote:

The fine weather should last for a while too, as I've implied with my
similar forecast for 3 days time, but a change may be a-coming for 10
days time - the ECM is leading that possibility but the gfs has not
shown enough consistency yet; some runs having dallied with a
continuance of the anticyclonic weather whilst others have shown a
return to Atlantic weather over the last 48 hours. Another couple of
gfs runs showing windy and wet weather at T240 and I'd be convinced
this blocking pattern won't last to the end of the third week of
September.

This illustrates perfectly the difficulties of forecasting at 10 days
and the need for both gfs consistency and ECM agreement for me to be
able to forecast with any degree of accuracy at that distance.

After writing the above, yesterday, The 00z gfs and the runs last
night, have shown a continuance of the higher pressure out to T240, at
least for England. The 00z ECM shows an Atlantic low stalling. What do
you forecast?



Well the Meto is hedging its bets, but this forecast was issued at
lunch yesterday and, as usual in the morning, is a day out of date.

"UK Outlook for Tuesday 15 Sep 2009 to Thursday 24 Sep 2009:
Much of the country will remain dry through the middle of next week
and over next weekend, but with variable amounts of cloud. Some sunny
spells are likely, more especially in the southwest of England and
Southwest Wales at first. The far Northwest of Scotland could see a
little little rain at times, with also a small risk of showers
extending into far south and southeast of England. Temperatures in all
parts should be near normal, and feeling pleasant in sunshine.
**Southern and Central parts should start mainly dry and fine in the
longer outlook, but there is a low risk of it turning more unsettled
with time. The Northwest is expected to turn more unsettled with
occasional showers or rain.**"

Updated: 1201 on Thu 10 Sep 2009

That's also an interesting comment in the 6-15 day forecast because
that phrase gives an insight into the forecaster's thinking - more
likely to continue settled over England, but a chance of it not doing
so. It also reflects my thinking that an actual forecast would have
less than a 75% chance of being correct.

Therein lies the current problems of forecasting at 10 days. It really
is very difficult.

Still super weather for most. Cool nights and mornings and a
scintillating September day on the south coast yesterday. Hopefully
another one to come. 20C and sunshine is just marvellous weather and
the September light, especially on a morning is quite superb.