May had two contrasting halves: a generally southeasterly
first half and a largely cyclonic second half. The first half
was abnormally warm, and in Scotland, Northern Ireland,
northwest England and north Wales it was also very dry
and very sunny. The second half, unsurprisingly, was
very wet.

More available:
Charts: http://www.climate-uk.com/monpre/0605.htm
The Monthly Review is already up at::
http://www.climate-uk.com/monthly/0605.htm
Graphs: http://www.climate-uk.com/graphs/0605.htm and
http://www.climate-uk.com/graphs/200605.htm
Not The Long Range Forecast is already up at
http://www.climate-uk.com/page4.html

The mean sea-level chart shows that the Icelandic Low was
more intense than usual at 1008 mbar, and displaced a long
way south of its usual position at 53N 21W. The Azores
high was scarcely discernible, the highest pressure of just
1020mbar located just SE of those islands. The seasonal
Arctic anticyclone extended quite prominently into Greenland.


The main feature of the sea-level pressure anomaly field
was a broad zone of below-average pressure extending from
northwest Russia across the British Isles and much of the
northern Atlantic to sub-tropical latitudes south of the Azores.

The main centres a
-7mbar at48N 30W
-3mbar over the Gulf of Bothnia
+4mbar over southern Greenland
+3.5mbar over the French Alps
Over the British Isles pressure anomaly ranged from -0.5mbar
in Kent to -3.5mbar in northwest Ireland. The anomalous flow
was SW-ly south of lat 57N, but E-ly north of lat 57N.
CET (after Manley) 12.2°C (+0.9 degC wrt 1971-2000)
CET (after Hadley) 12.4°C (+1.1 degC)
and by this measure it was the warmest May since 2001.
E&W Rain: 114.9mm (187% of 1971-2000 mean)
The wettest days were 6th and 17th-22nd
E&W Sunshine: 179.1 hr ( 89% of 1971-2000 mean)
The first half was much sunnier than the second half.
CScotT: 10.2°C (+0.3 degC)
ScotRain: 75.4mm (133%)
ScotSun: 212.8hr (119%)

NIT: 10.8°C (+0.5 degC)
NI Rain: 87.6mm (172%)
NI Sun: 217.4 hr (111%)

Rainfall totals ranged from 237.0mm at Inveruglas (Argyll)
to 38.4mm at St Peter Port (Guernsey).
Percentages ranged from 325 at Milford Haven (Pembrokeshire)
to 78 at St Helier (Jersey). It was the wettest May on record
at several sites in England and Wales including Wattisham and
Milford Haven.

Sunshine totals ranged from 261.3hr at Fair Isle and 253.4hr
at Lerwick (Shetland) - both CS recorders - to 127.5hr at
Wattisham (Suffolk) - a KZ sensor. Percentages ranged from
165 at Lerwick (Shetland) - on the CS recorder - to 64 at
Herstmonceux (Sussex) - a KZ sensor and probably over-sheltered
as well.

(c) Philip Eden