Although the long September anticyclonic spell crumbled quickly
during the opening days of October, there was a further
anticyclonic period between the 12th and 18th, and an
anticyclonic/southerly period from the 26th onwards. Westerly
and southwesterly winds blew less frequently than usual during
October, and gales were few.

Mean pressure charts will soon be uploaded to:
Charts:   http://www.climate-uk.com/monpre/0910.htm
The Monthly Review will shortly be made available at:
http://www.climate-uk.com/monthly/0910.htm
Graphs:  http://www.climate-uk.com/graphs/0910.htm  and
              http://www.climate-uk.com/graphs/200910.htm
Not The Long Range Forecast should be available by Nov 5 on:
              http://www.climate-uk.com/page4.html

The mean sea-level pressure distribution over the Atlantic/Europe
sector during October 2009 showed a relatively weak pattern, but
a key element was the complete absence of the Azores High. The
Icelandic Low was weaker than usual and displaced south of
its normal position, to be 1003mbar at58N 26W. There was a
further low centre of 1000 mbar in the northern Barents Sea. The
main high pressure centres were 1018mbar over northwest
Greenland and 1018mbar over central France. The mean flow
over the British Isles was weakly SW-ly.

Aloft, there was a marked trough at 500mbar at longitude
35-50W, and a ridge around 00-10E.

The sea-level pressure anomaly field showed below average
pressure across the Atlantic/Europe sector south of latitude
55N, and above average pressure over Greenland, Iceland, the
Norwegian Sea, the British Isles and most of Scandinavia.
The main anomaly centres were:
+ 8mbar off NE Iceland and over central Greenland
- 11mbar just NW of the Azores
-  5mbar over Romania

Over the British Isles pressure anomaly ranged from -1mbar
at Valentia to +3.5mbar at Lerwick. The anomalous flow was
very weakly E to SEly.

CET (after Manley)   11.37°C  (1.0degC above the 1971-2000 mean)
CET (after Hadley)    11.5 or 11.6°C   (1.1 or 1.2degC above)
E&W Rain (provisional):    73.1mm  (  77% of 1971-2000 mean)
E&W Sunshine (prov):       98.8hr    (  88% of 1971-2000 mean)

Over England and Wales as a whole it was the driest October
for two years, the warmest for three, and the dullest for four.

CScotT:      10.7°C  (+1.0degC)
ScotRain:     121mm  (110 %)
ScotSun:        89hr     (100 %)

NIT:          11.6°C  (+1.2degC)
NI Rain:       92mm  (  93 %)
NI Sun:        80hr    (  87 %)

Rainfall totals ranged from 313mm at Inveruglas (Dunbartonshire)
and 299mm at Cluanie Inn (Wester Ross) to 26mm at
Andrewsfield (Essex) and 27mm at the Olympics site in London.

Percentages ranged from 204 at Dyce (Aberdeenshire) to
51 at Andrewsfield (Essex) and Kenley (Surrey).

Sunshine totals ranged from 114h at Brize Norton (Oxon) and
113h at Lyneham (Wilts) [both CS recorders] to just 49h at
Kinlochewe (Wester Ross) [KZ, horizon obstructed] and 57h
at Lerwick (Shetland) [KZ sensor].

Percentages ranged from 107 at Brize Norton (Oxon)
to 65 at Boulmer (Northumberland).   [The usual caveat about
the change in sunshine recorders applies]

(c) Philip Eden

"Philip Eden" <philipATweatherHYPHENukDOTcom> wrote:

Courtesy of the University of Bangor, I'm advised that
the temperature at the University Farm at Aber (north coast
of Caernarfon, in the lee of Snowdon) the temperature reached
20.2°C on the 27th, 19.9°C on the 29th and 20.5°C on
the 30th October.
>
> (c) Philip Eden
>
>