weather of Thursday 6th and Friday 7th is now but a memory, but it is one that
will stay with us a long time. Highest temperatures on Thursday afternoon were 18.8ºC
at Northolt and Kensington, and 18.4ºC at Heathrow, while on Friday the warmest
weather migrated westward and northward, giving 20.2ºC at Lochcarron
and 19.5ºC at Aultbea, both in Wester
Ross, 19.6ºC at Llanbedr in Merionethshire, 19.1ºC at
Broadford on Skye, and 18.8ºC at Kinloss
warmth in November in the UK is almost always imported – delivered
from sub-tropical latitudes by a strong southwesterly or southerly wind. In the
lee of high ground the warmth is accentuated by the compression of air
descending the mountain slopes, a mechanism known as the "foehn effect", after the warm and very dry foehn wind of the Swiss and Austrian Alps. November
sunshine is feeble and low in the sky, so the warmth of the sun contributes
relatively little to temperature levels on these rare warm days.
November temperature ever recorded in the UK under standard conditions was 21.7ºC,
measured at Prestatyn, Flintshire, on 4
Nearby Hawarden Bridge reported 21.1ºC, and although maxima of 18-20ºC were
observed widely elsewhere it is clear that on this occasion the foehn effect provided sufficient added impetus to give the
record to the northeastern corner of Wales.
Similarly, Edinburgh's 20.6ºC and Dublin's 20.0ºC on the same date are the highest
November temperatures ever recorded in Scotland and the IrishRepublic respectively courtesy of the Southern
Uplands and the WicklowMountains respectively.
England's highest for the month happened on 5
when 21.1C was recorded at several sites in East Anglia and the Southeast including London, Chelmsford and Cambridge. On this occasion a stiff
southwesterly breeze was accompanied in eastern counties by several hours of
bright sunshine which lifted temperatures by 2-3 degCwhen compared with cloudier regions
further west and north.
example of extreme November warmth was a recent occurrence, in 1997, when new
date-records were established on 15 to 18 November inclusive. Cloudy skies and
a strong southeasterly wind meant that the foehn effect was very much in evidence, and this was emphasised
by the fact that highest readings were obtained along the coast of north Wales. Indeed, the maximum on the 17th of
20.7ºC at Aber, four miles east of Bangor, occurred at – nearly three hours after sunset.