On Feb 1, 3:38 pm, "Philip Eden" philipATweatherHYPHENukDOTcom
wrote:
Perhaps surprisingly for such a warm month, there was a
significant northerly component to the anomalous flow
over the British Isles during January. However, the
southerliness index is only very weakly correlated to
temperature during the winter quarter ... much of the
variance in mean temperature is explained by the magnitude
of the westerliness index (with a smaller contribution
from the cyclonicity index). It was, in fact, the most westerly
January since 1983, and the 11th most westerly January
in 133 years of records. The strength of the westerlies also
resulted in a strongly orographically-modulated rainfall
distribution (biggest percentages on west-facing upslopes
and lowest percentages in the usual rain-shadow areas).
Similarly, it was also a very sunny month in parts of
SE Scotland and NE England, but a dull one in western
Scotland.

Mean pressure charts are now be available at:
Charts: http://www.climate-uk.com/monpre/0701.htm
The Monthly Review will shortly be uploaded to:http://www.climate-uk.com/monthly/0701.htm
Graphs: http://www.climate-uk.com/graphs/0701.htm and
http://www.climate-uk.com/graphs/200701.htm
Not The Long Range Forecast will be found after 3 Feb at:
http://www.climate-uk.com/page4.html

The mean sea-level chart shows that the Icelandic Low was
split, with on the one hand a pair of centres at 987mbar in
the Barents and north Norwegian Seas, and on the other
hand a centre of 994mbar near the southern tip of Greenland.
(Such a split is very often a precursor of a lengthy blocking
episode in the northeast Atlantic with a delay of 2-3 weeks).
High pressure lay in a broad zone from Bermuda across the
Azores, Iberia and the Mediterranean to the Levant; the
main centre of 1029mbar was located just north of Madeira.
The flow over the British Isles was due-westerly and more
than twice as strong as the long-term mean.

The sea-level pressure anomaly field showed below-
normal pressure over northern and eastern Europe, the
northern Atlantic, northeast Canada and adjacent parts of
the Arctic, and above-normal pressure over southern
Europe, Biscay and southern and central parts of the
North Atlantic Ocean.
The main anomaly centres we
-19mbar over Novaya Zemlya and Finland
-9mbar over the Labrador coast
+9mbar over the Atlantic between Ireland and the Azores
+8mbar in the central Mediterranean

Over the British Isles pressure anomaly ranged from +5mbar
at Scilly to -9mbar in Shetland. The anomalous flow was
strongly WNW-ly, tending NW-ly in northern Scotland.

CET (after Manley) 7.0°C (+2.8 degC wrt 1971-2000)
making it the warmest since 1921 and the fifth warmest
in the 349-year long record
CET (after Hadley) 6.9 or 7.0°C (+2.7 or 2.8 degC)
E&W Rain (provisional): 100.2mm (107% of 1971-2000 mean)
the highest since 2004
E&W Sunshine (prov): 65.4 hr (118% of 1971-2000 mean)
the highest since 2003

CScotT: 6.1°C (+2.4 degC)
ScotRain: 145.5mm (128%)
ScotSun: 45.0hr (103%)

NIT: 6.8°C (+1.8 degC)
NI Rain: 106.1mm (114%)
NI Sun: 57.9hr (115%)

Rainfall totals ranged from 591.6mm at Inveruglas (Dunbartonshire)
to 31.3mm at Coningsby (Lincs). It was the equal-wettest January
(alongside 2005) in the Renfrew/Abbotsinch/Bishopton record (just
west of Glasgow) since 1928, while the 3-month total (Nov,Dec,Jan)
in the southwest Highlands and the Clydeside area was almost 250%
of the normal and far in excess of anything previously recorded for
these months.

Percentages ranged from 251 at Lake Vyrnwy (Montgomeryshire)
to 42 at Glenlivet (Banffshire) [flagged as in need of checking;
possibly too low]

Sunshine totals ranged from 91.1h at Boulmer, Northumberland
(KZ sensor) where it was the sunniest Jan since 1991, to
21.5h at Stornoway (KZ sensor).

Percentages ranged from 172 at Church Fenton (near York)
to 51 at Prestwick.

One interesting additional statistic: at Lerwick the Januarys of
both 2006 and 2005 were warmer.

(c) Philip Eden

Isn't the mean flow anomaly a little misleading, at least
to someone unversed in these matters? The monthly flow was mainly
SW'ly but with a week of northerlies, to put it rather simply, and
there was very little in between. It's true that the mean flow is as
stated and it is quite in order to make correlations with temperature
and rainfall but it doesn't quite give the flavour of the month, if
you'll excuse the phrase.

Tudor Hughes, Warlingham, Surrey.