Well for Sunday, the max in Penzance will be between 16C & 27C. So it may be cool, or then again it may be hot. In the last 22 years only 8 days would not have fallen into that category, so as forecasts go it's a cracker.

Now, I know they give a likely Max, but for today it's 16C, with a likely temperature at both 13:00 & 16:00 of 15C. Then again it may reach 22C, take your pick.

As it happens, @ 11:30 it was 16C @ Lands End, 17.5C in Penzance, 18C on St. Martin's Scilly, despite a thin broken cover of Sc. I expect a similar max to yesterday (when it reached19.2C) before the easterly drift brings the hot air down at the week end.

Graham
Penzance

Before anyone picks me up, the word July should be inserted in sentence:-

In the last 22 years only 8 days

Graham

On Friday, 5 July 2013 12:05:51 UTC+1, Graham Easterling wrote:
Well for Sunday, the max in Penzance will be between 16C & 27C. So it may be cool, or then again it may be hot. In the last 22 years only 8 days would not have fallen into that category, so as forecasts go it's a cracker.

I've noticed your posts on this before Graham - do we have anyone on here who can detail how these forecasts are produced? Is the output from a range of short-range ensembles? This could be as subtle as an onshore flow with clag and a hot offshore flow in two of the ensembles and the rest falling in between.

If it is ensemble output it would be much better - a la ECMWF from ensemble output I've seen - for the range to be shown but the width of the bar being representative of the number of ensemble members at that temperature. Although would this be digestible for the casual website viewer? They could even be daring and remove any really screwy ensemble members...which would of course tempt fate...

Richard

On Fri, 5 Jul 2013 04:36:30 -0700 (PDT)
Richard Dixon wrote:

On Friday, 5 July 2013 12:05:51 UTC+1, Graham Easterling wrote:
Well for Sunday, the max in Penzance will be between 16C & 27C. So
it may be cool, or then again it may be hot. In the last 22 years
only 8 days would not have fallen into that category, so as
forecasts go it's a cracker.

I've noticed your posts on this before Graham - do we have anyone on
here who can detail how these forecasts are produced? Is the output
from a range of short-range ensembles? This could be as subtle as an
onshore flow with clag and a hot offshore flow in two of the
ensembles and the rest falling in between.

If it is ensemble output it would be much better - a la ECMWF from
ensemble output I've seen - for the range to be shown but the width
of the bar being representative of the number of ensemble members at
that temperature. Although would this be digestible for the casual
website viewer? They could even be daring and remove any really
screwy ensemble members...which would of course tempt fate...


These single-station forecasts used to be automatically produced from
the UM forecast using Model Output Statistics. That was a decade ago so
things may have changed.

Just looked at Bracknell and for tomorrow, the most likely value is 24C
in a range of 24-25C! That seems surprisingly tight for a 90% range.
Ranges are 4C for Sunday and 6C for the next couple of days.

--
Graham P Davis, Bracknell, Berks.
A lot of care homes use computer games to keep their residents
physically active. That's why old people smell of wii.
[https://twitter.com/BridgetandJoan]

do we have anyone on here who
can detail how these forecasts are produced? Is the output from a
range
of short-range ensembles?

I think they are derived from short-range ensembles from more than
one model.

--
Freddie
Castle Pulverbatch
Shropshire
221m AMSL

On 05/07/2013 12:05 PM, Graham Easterling wrote:
Well for Sunday, the max in Penzance will be between 16C& 27C. So it may be cool, or then again it may be hot. In the last 22 years only 8 days would not have fallen into that category, so as forecasts go it's a cracker.

The Met Office forecasts for Sidmouth, whilst not as rubbish as for
Penzance, they always give a maximum temperature lower than the reality
under these conditions.

The forecast is for 19°C today. I just checked and it is currently 21°C
so will likely end up being 23°C.

--
Nick G
Otter Valley, Devon
20 m amsl
http://www.ottervalley.co.uk

On Friday, July 5, 2013 12:58:42 PM UTC+1, Nick Gardner wrote:
On 05/07/2013 12:05 PM, Graham Easterling wrote:

Well for Sunday, the max in Penzance will be between 16C& 27C. So it may be cool, or then again it may be hot. In the last 22 years only 8 days would not have fallen into that category, so as forecasts go it's a cracker.

The Met Office forecasts for Sidmouth, whilst not as rubbish as for
Penzance, they always give a maximum temperature lower than the reality
under these conditions.

The forecast is for 19�C today. I just checked and it is currently 21�C
so will likely end up being 23�C.

Nick G

Otter Valley, Devon

20 m amsl

http://www.ottervalley.co.uk

19.2C here by 13:00, so it will be warmer than yesterday.

See the UV on St. Martin's http://www.weatherlink.com/user/tape...mary&headers=1 ! That's through thin Sc, which has now largely burnt off on the mainland http://www.minack.com/webcamsref.htm .

Graham

On Friday, July 5, 2013 12:58:42 PM UTC+1, Nick Gardner wrote:
On 05/07/2013 12:05 PM, Graham Easterling wrote:

Well for Sunday, the max in Penzance will be between 16C& 27C. So it may be cool, or then again it may be hot. In the last 22 years only 8 days would not have fallen into that category, so as forecasts go it's a cracker.



The Met Office forecasts for Sidmouth, whilst not as rubbish as for

Penzance, they always give a maximum temperature lower than the reality

under these conditions.



The forecast is for 19�C today. I just checked and it is currently 21�C

so will likely end up being 23�C.



--

Nick G

Otter Valley, Devon

20 m amsl

http://www.ottervalley.co.uk

I have got to agree with Graham and Nick.
Those of us that live down here in SW England suffer from a sort of blindness on the part of the MO forecasts. Surprising as the HQ of UKMO is in Exeter, but clearly the temp forecasts are just machine produced.
The tourist industry has complained for years that lower than reality temps are forecast for the SW in summer.
The BBC TV forecasts nationally reach the max number of people and all this last week they have plonked a 15C over the SW.
We have reached 20C on most days.
Online the forecast yesterday for Plymouth gave a max of 16C. We got 19C.
20C in my garden.

It is all very weird. In a crude way they seem to be knocking 5C off the SE England max temperature and saying yep, that will do for the SouthWest.

Len
in glorious sunny Wembury, SW Devon

On Fri, 5 Jul 2013 04:05:51 -0700 (PDT), Graham Easterling
wrote:
Well for Sunday, the max in Penzance will be between 16C & 27C. So
it may be cool, or then again it may be hot.
I think those temperatures represent the outer bounds of the likely
forecast values, so it's a bit misleading to make the statement you
did without bearing this in mind. Think of it this way: temperatures
of 16 and 27 are 95% unlikely to occur. As Richard says in another
reply, they are likely to represent situations in which you either
have an offshore drift of land-warmed air all day, or you have an
onshore drift all day accompanied by sea fog and/or low cloud. The
reality will likely fall between the two extremes (i.e a sea breeze
occurs at some point, but after land-warmed air has affected the
point of interest). This will be represented by the "most likely"
temperature, which is the one you should use if you just want a
forecast temperature and are not interested in unlikely scenarios.
This is all explained on the Meto web site.

--
Freddie
Castle Pulverbatch
Shropshire
221m AMSL

I think those temperatures represent the outer bounds of the likely
forecast values, so it's a bit misleading to make the statement you
did without bearing this in mind. Think of it this way: temperatures
of 16 and 27 are 95% unlikely to occur. As Richard says in another
reply, they are likely to represent situations in which you either
have an offshore drift of land-warmed air all day, or you have an
onshore drift all day accompanied by sea fog and/or low cloud. The
reality will likely fall between the two extremes (i.e a sea breeze
occurs at some point, but after land-warmed air has affected the
point of interest). This will be represented by the "most likely"
temperature, which is the one you should use if you just want a
forecast temperature and are not interested in unlikely scenarios.
This is all explained on the Meto web site.

Freddie

Castle Pulverbatch

Shropshire

221m AMSL

Sorry, the forecasts are complete rubbish.

The Penzance forecast for today has just been amended (16:00) to possible maxes between 14C & 22C, (from 16-22) likely max 16C!

It's been 18C since 11:00, at 13:00 it was 19.2C, so how come the lower end of the range has been reduced to 14C, it's been up to 15C out on the Sevestones lightship miles off Land's End! I've only EVER in 22 years recorded 1 day in July with a max that low (13.5C on 13th 1997). A sea breeze has now set in and it's still near 18C, not surprising as the SST close in is pushing 16C. I mean how can this http://www.metoffice.gov.uk/public/w...ce?tab=fiveDay be
regarded as in any way useful as a forecast. It might be cool, then it could be hot.

It's been so bad, I kept a record in June of the 'likely max' forecast when I've got up un the morning, and what it actually reached. The average discrepancy was 3.2C - that's a lot. The 'highest max' is actually, on average a lot closer. There is no excuse. AS Nick G says, it is an endemic problem along the coast at this time of year, which has got a lot worse.

Graham