In spite of the long anticyclonic period during the second half
of the month, December was dominated by southwesterly
winds to the extent that it was the third most southwesterly
December in the last 100 years (after 1974 and 1912). As a
result it was the warmest December, averaged nationally,
since 1988, while the rainfall distribution showed strong
orographic modulation especially over Scotland and northern
England. Sunshine, too, ranged from well below average in
western Scotland to far above average in eastern Scotland and
northeast England.

Mean pressure charts will shortly be available at:
Charts: http://www.climate-uk.com/monpre/0612.htm
The Monthly Review will be uploaded to:
http://www.climate-uk.com/monthly/0612.htm
Graphs: http://www.climate-uk.com/graphs/0612.htm and
http://www.climate-uk.com/graphs/200612.htm
Not The Long Range Forecast will soon be to be found at:
http://www.climate-uk.com/page4.html

The mean sea-level chart shows that the Icelandic Low was
pretty much in its normal position but it was considerably
more intense than usual, centred 987mbar at 62N 35W.
A secondary centre of 991mbar was located in the Barents
Sea. Highest pressure lay over southern Europe with centres
of 1029 mbar over SW Romania and 1028mbar over
western Spain, with a strong ridge extending WSW into
the Atlantic to where the Azores high would normally be.

The sea-level pressure anomaly field was showed below-
normal pressure over northern Europe, the northern Atlantic,
northeast Canada and adjacent parts of the Arctic, and
above-normal pressure over central and southern Europe
and sub-tropical parts of the Atlantic.

The main anomaly centres we
-15mbar over SE Greenland
-12mbar in the north Barents Sea
+11mbar over Serbia

Over the British Isles pressure anomaly ranged from +5mbar
in Kent to -5mbar in Shetland the the Western Isles. The
anomalous flow was strongly SW-ly.

CET (after Manley) 6.6°C (+1.5 degC wrt 1971-2000)
making it the warmest since 1988
CET (after Hadley) 6.5 or 6.6°C (+1.4 or 1.5 degC)
E&W Rain (provisional): 114.6mm (113% of 1971-2000 mean)
E&W Sunshine (prov): 51.3 hr (107% of 1971-2000 mean)

CScotT: 5.5°C (+1.0 degC)
ScotRain: 152.7mm (135%)
ScotSun: 47.6hr (135%)

NIT: 6.6°C (+0.4 degC)
NI Rain: 119.0mm (117%)
NI Sun: 59.0hr (155%)

Rainfall totals ranged from 685.5mm at Inveruglas (Dunbartonshire)
to 29.8mm at Dyce (Aberdeenshire). It was the wettest December
since records began in 1921 in the Renfrew/Abbotsinch/Bishopton
record (just west of Glasgow) while it was the driest since 1991 at
Dyce.

Percentages ranged from 298 at Wilsden (West Yorks) to
35 at Dyce.

Sunshine totals ranged from 88.0h at Dyce (KZ sensor) to
13.9h at Lerwick (KZ sensor).

Percentages ranged from 194 at Dyce to 64 at Prestwick.
It was the sunniest December on record at Dyce where the
previous record, 67h in 1951, was smashed out of sight,
and also at Boulmer (Northumberland).

(c) Philip Eden