Midday temperatures:-
2nd 7C (Eventual 0900-0900 max 8.4)
3rd 12C (0900-0900 max 12.4)
4th 5C

The forecast was much the same for each day. The 7th saw a good deal
of sun, but the edge of the cloud was very close to the north. 3rd -
basically no cloud within 100miles. Today, sunny spells this morning,
but thicker cloud just to the south, breaking near the south coast.

A mainly blue slot now approaching so the temperature should rise 2 or
3 degrees soon. Much of southern/central Cornwall around 6-8C colder
than at same time yesterday.

Similar synoptics, very different weather.

Graham
Penzance

On Mar 4, 1:09*pm, Graham Easterling wrote:
Midday temperatures:-
2nd *7C * * (Eventual 0900-0900 max 8.4)
3rd * 12C * (0900-0900 max 12.4)
4th * 5C

The forecast was much the same for each day. The 7th saw a good deal
of sun, but the edge of the cloud was very close to the north. 3rd -
basically no cloud within 100miles. Today, sunny spells this morning,
but thicker cloud just to the south, breaking near the south coast.

A mainly blue slot now approaching so the temperature should rise 2 or
3 degrees soon. Much of southern/central Cornwall around 6-8C colder
than at same time yesterday.

Similar synoptics, very different weather.

Graham
Penzance

The temperature drop should have been expected Graham because
yesterday's midday output from the Met Office NAE model had shown a
cold pool moving westwards over northern France and the Channel today.
It predicted a drop of about 25 geopotential metres in the 1000-850mb
thickness over Cornwall between yesterday and today. Under cloudless
skies this would equate to a fall of 4C, but if you allow for about 5
or 6 oktas of cloud today, then the drop would be about 6C.

Dick Lovett

On Mar 4, 3:02*pm, Dick wrote:
On Mar 4, 1:09*pm, Graham Easterling wrote:





Midday temperatures:-
2nd *7C * * (Eventual 0900-0900 max 8.4)
3rd * 12C * (0900-0900 max 12.4)
4th * 5C

The forecast was much the same for each day. The 7th saw a good deal
of sun, but the edge of the cloud was very close to the north. 3rd -
basically no cloud within 100miles. Today, sunny spells this morning,
but thicker cloud just to the south, breaking near the south coast.

A mainly blue slot now approaching so the temperature should rise 2 or
3 degrees soon. Much of southern/central Cornwall around 6-8C colder
than at same time yesterday.

Similar synoptics, very different weather.

Graham
Penzance

The temperature drop should have been expected Graham because
yesterday's midday output from the Met Office NAE model had shown a
cold pool moving westwards over northern France and the Channel today.
It predicted a drop of about 25 geopotential metres in the 1000-850mb
thickness over Cornwall between yesterday and today. Under cloudless
skies this would equate to a fall of 4C, but if you allow for about 5
or 6 oktas of cloud today, then the drop would be about 6C.

Dick Lovett- Hide quoted text -

- Show quoted text -

It was strange this wasn't taken into account in yesterday evening's
forecasts. E.g both the main forecast at 18:30 & the following local
forecast gave 12C max for Plymouth today. The previous evening they
had forecast 8C & it reached 13C! So completely the wrong way around.

I had noticed how low temperatures were at the Channel Light Vessel
yesterday afternoon, just 4C.

Graham
Penzance

On Mar 4, 4:03*pm, Graham Easterling wrote:
On Mar 4, 3:02*pm, Dick wrote:





On Mar 4, 1:09*pm, Graham Easterling wrote:

Midday temperatures:-
2nd *7C * * (Eventual 0900-0900 max 8.4)
3rd * 12C * (0900-0900 max 12.4)
4th * 5C

The forecast was much the same for each day. The 7th saw a good deal
of sun, but the edge of the cloud was very close to the north. 3rd -
basically no cloud within 100miles. Today, sunny spells this morning,
but thicker cloud just to the south, breaking near the south coast.

A mainly blue slot now approaching so the temperature should rise 2 or
3 degrees soon. Much of southern/central Cornwall around 6-8C colder
than at same time yesterday.

Similar synoptics, very different weather.

Graham
Penzance

The temperature drop should have been expected Graham because
yesterday's midday output from the Met Office NAE model had shown a
cold pool moving westwards over northern France and the Channel today.
It predicted a drop of about 25 geopotential metres in the 1000-850mb
thickness over Cornwall between yesterday and today. Under cloudless
skies this would equate to a fall of 4C, but if you allow for about 5
or 6 oktas of cloud today, then the drop would be about 6C.

Dick Lovett- Hide quoted text -

- Show quoted text -

It was strange this wasn't taken into account in yesterday evening's
forecasts. E.g both the main forecast at 18:30 & the following local
forecast gave 12C max for Plymouth today. The previous evening they
had forecast 8C & it reached 13C! So completely the wrong way around.

I had noticed how low temperatures were at the Channel Light Vessel
yesterday afternoon, just 4C.

Graham
Penzance- Hide quoted text -

- Show quoted text -

A possible reason is that the temperature forecasts for towns & cities
are probably still derived from MOS data (Model Output Statistics)
where predictions of relevant parameters are compared, with the known
climatology of the location, via a statistical regression. I think the
method still relies heavily on model predictions of temperatures in
the 900-850mb layer. Camborne's midday ascents showed that both 900
and 850 mb temperatures were virtually the same on both days. The big
difference was in the much colder air below 900mb yesterday, which
would be accounted for in the thickness of the 1000-850mb layer.

Dick Lovett

On Mar 5, 10:25*am, Dick wrote:
On Mar 4, 4:03*pm, Graham Easterling wrote:





On Mar 4, 3:02*pm, Dick wrote:

On Mar 4, 1:09*pm, Graham Easterling wrote:

Midday temperatures:-
2nd *7C * * (Eventual 0900-0900 max 8.4)
3rd * 12C * (0900-0900 max 12.4)
4th * 5C

The forecast was much the same for each day. The 7th saw a good deal
of sun, but the edge of the cloud was very close to the north. 3rd -
basically no cloud within 100miles. Today, sunny spells this morning,
but thicker cloud just to the south, breaking near the south coast.

A mainly blue slot now approaching so the temperature should rise 2 or
3 degrees soon. Much of southern/central Cornwall around 6-8C colder
than at same time yesterday.

Similar synoptics, very different weather.

Graham
Penzance

The temperature drop should have been expected Graham because
yesterday's midday output from the Met Office NAE model had shown a
cold pool moving westwards over northern France and the Channel today..
It predicted a drop of about 25 geopotential metres in the 1000-850mb
thickness over Cornwall between yesterday and today. Under cloudless
skies this would equate to a fall of 4C, but if you allow for about 5
or 6 oktas of cloud today, then the drop would be about 6C.

Dick Lovett- Hide quoted text -

- Show quoted text -

It was strange this wasn't taken into account in yesterday evening's
forecasts. E.g both the main forecast at 18:30 & the following local
forecast gave 12C max for Plymouth today. The previous evening they
had forecast 8C & it reached 13C! So completely the wrong way around.

I had noticed how low temperatures were at the Channel Light Vessel
yesterday afternoon, just 4C.

Graham
Penzance- Hide quoted text -

- Show quoted text -

A possible reason is that the temperature forecasts for towns & cities
are probably still derived from MOS data (Model Output Statistics)
where predictions of relevant parameters are compared, with the known
climatology of the location, via a statistical regression. I think the
method still relies heavily on model predictions of temperatures in
the 900-850mb layer. Camborne's midday ascents showed that both 900
and 850 mb temperatures were virtually the same on both days. The big
difference was in the much colder air below 900mb yesterday, which
would be accounted for in the thickness of the 1000-850mb layer.

Dick Lovett- Hide quoted text -

- Show quoted text -

Thanks Dick,

Graham

SNIP


I understand that predicted temperatures forPenzanceare compared
with actual data from Camborne, (info from a MetO contact). As you
would be aware, a north coast location is very different to a south
coast one. As a result, last Summer thePenzanceforecast temperature
was consistently very, very low with a NW airstream, and warm for a
southerly one.

It's worth adding that if you go to the MetO website for recentPenzance
weather, what you see is the Camborne data - (XCWeather does
show thePenzanceheliport conditions.) TheCuldrosedata is better,
as it's well away from the north coast the temperature profile is more
similar. Just add on typically 1-2C to allow for the shelter/altitude
difference off Penzance.

*Graham
Penzance

Today is a good exmple. The wind is just onshore on the north coast.
It is 16C in Penzance and 16C at windblown & exposed Culdrose
http://www.metoffice.gov.uk/weather/...t_weather.html

Near the north coast it is around 10C at Camborne.

So, if you go to the forecast for Penzance, you get 11C forecast for
15:00 http://www.metoffice.gov.uk/weather/...t_weather.html
, and if you click the recent weather button you see the forecast is
spot on as it was 10.1C at noon!

This is the way the forecast is validated - Complete boll*cks
basically. (It clearly annoys me!)

Graham
Penzance

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