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| May 2001 monthly assessment issued
1/6/2001 |
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Monthly summaries available for: England
and Wales | Scotland | Northern
Ireland
Homogenous time series based upon selected station data:
CET | England and Wales
rainfall
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| Very warm with some thunder after a
chilly start. Cool wet spell with thunderstorms mid-month.
Mostly dry very warm and sunny thereafter, more changeable
towards end of month. |
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Diary of highlights
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1st - 3rd Rather unsettled and mostly cold
with some thundery rain especially in south-east England
and East Anglia. Drier and brighter in the north-west.
4th - 12th With high pressure firmly established off
Scotland the weather was mainly dry and sunny especially
in the north. There was patchy fog at times especially around
coasts. Many places had overnight frost at first, Shap Fell
/ Cumbria fell to -3.9 °C early on the 7th. Some thundery
rain with hail and spectacular lightning broke out overnight
the 9th/10th mainly over south-east England, East Anglia
and south-west England. Thunderstorms also occurred over
the south-east Midlands on the 11th. By the 11th and 12th
it had become very warm or hot in many areas with prolonged
sunshine, Southampton peaked at 27.3 °C on the 12th.
13th - 17th Low pressure centres
traversing the region brought frequent outbreaks of
heavy thundery rain to many areas, especially in the the
south, south-east and Midlands, with some localities
experiencing torrential downpours. It was very warm at
first but became colder later, the 17th being especially
cold, wet and windy.
18th - 25th After some
scattered showers and thundery outbreaks petered out on
the 18th high pressure migrated quickly from the
south-west to cover the region. Although somewhat cloudy
at first in north-western areas long sunny periods soon
prevailed everywhere. Dry, warm or very warm conditions
were established, especially in Wales and western areas.
Counties nearer the relatively cool North Sea had their
temperatures moderated to some extent by the onshore
breezes.
26th - 27th As the high pressure
moved south more changeable (though still warm) weather
began to affect the region. As weak fronts crossed
England and Wales, patchy rain and drizzle with hill and
coastal fog affected many western and north-western
areas, with the rain being heavy over north Wales on the
27th.
28th - 31st The warm or very warm theme
continued with most places having long sunny periods,
although there were areas of patchy rain in the west at
first. During the 30th heavy rain affected northern
England, and thunder was reported from Norfolk later.
The 31st was cooler with showers down the east coast of
England.
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| Statistical details (using best available
data/estimates): updated 2003 |
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England & Wales Mean Temperature Series (series
began in 1961).
The final value for the month was 12.0 °C, which
is 1.5 °C above the 1961-1990 average, which is
in the well above average category.
England & Wales Rainfall Series (series began
in 1961).
The final total for the month was 42.5 mm, which is
67 % of the 1961-1990 average, which is in the below
average category.
England & Wales Sunshine Series (series began
in 1961).
The final total for the month was 226.3 hours, which is
121 % of the 1961-1990 average, which is in the well
above average category.
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| Scotland |
| Very dry, warm and sunny. |
| Diary of Highlights |
May 2001 was outstandingly dry, warm and sunny across
most of the Scottish mainland. Generally, the month did
not break records for individual elements, but the
combination of dryness, warmth and sunshine was notable.
May 2000 was almost as warm, and sunnier in the
south-west, but not as dry.
Two fine and sunny spells dominated the weather in
May, and were separated by more unsettled conditions.
The first fine spell was already knocking on the door
during the first four days of May as an anticyclone near
the Azores pushed a ridge of high pressure towards the
British Isles. Weak fronts and a few showers were in
evidence, but already there was much dry and sunny
weather. There were also some cold nights with frost in
places.
The anticyclone had moved close to Scotland by the 5th
and lasted until the 13th. It took a couple of days for
most of the cloud to disperse, and then most places enjoyed
sunny conditions for several days. There was still night
frost in a few places at first, but it became steadily
warmer and by the end of the spell temperatures were exceeding
25 °C in some locations.
The most unsettled weather of the month occurred
between the 14th and 19th as a large-scale fall of
pressure took place, resulting in a depression forming
over Scotland on the 16th. This gave a period of rain
before cool and showery weather spread across the
country in the wake of the low.
A steady build of pressure ensued and a new anticyclone
took residence close to Scotland from the 20th to 24th.
Once again, it took a couple of days for the cloud to
break and then there was more warm sunshine with temperatures
reaching 25 °C in one or two places.
By the 25th the high was slipping to the south to enable
a changeable west to south-westerly airstream to cover
Scotland. Weak fronts gave some outbreaks of rain, but
it remained warm, with temperatures reaching 21 °C
at some place in Scotland until the 28th. After this the
winds veered into the north-west and it became cooler,
with bright and showery conditions alternating with more
organised bands of rain.
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Statistical details (using
best available data/estimates): updated 2003
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Scotland Mean Temperature Series (series
began in 1961).
The final value for the month was 10.2 °C, which
is 1.8 °C above the 1961-1990 average, which is
in the well above average category. 2nd warmest in the
series, warmest 1992 with 10.4 °C.
Scotland Rainfall Series (series began in 1961).
The final total for the month was 43.1 mm, which is
50 % of the 1961-1990 average, which is in the well
below average category.
Scotland Sunshine Series (series began in 1961).
The final total for the month was 211.3 hours, which is
127 % of the 1961-1990 average, which is in the well
above average category.
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| Northern
Ireland |
| This was another dry, sunny May month. Although
not as sunny as in May 2000 (nor May 1997). |
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Diary of Highlights
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1st - 13th Largely dry and very sunny, but with showers
and thunderstorms recorded locally on the 9th and 10th.
Very warm on 12th and 13th.
14th - 16th Cold, dull and wet.
17th - 20th Dry and bright, but cool.
20th - 24th Dry, very warm and very sunny.
25th - 31st Turning increasingly unsettled, but staying
quite warm and sunny until 29th. Much cooler on 30th and
31st.
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Statistical details (using
best available data/estimates): updated 2003
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Northern Ireland Mean Temperature Series (series
began in 1961).
The final value for the month was 11.6 °C, which
is 2.0 °C above the 1961-1990 average, which is
in the exceptionally above average category. Warmest
in series, previous warmest 1992 with 11.4 °C.
Northern Ireland Rainfall Series (series began in
1961).
The final total for the month was 50.8 mm, which is
70 % of the 1961-1990 average, which is in the below
average category.
Northern Ireland Sunshine Series (series began in
1961).
The final total for the month was 203.1 hours, which is
118 % of the 1961-1990 average, which is in the above
average category.
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Homogeneous series based upon selected station data: updated
2003 |
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Central England Temperature (series begins in 1659).
The mean value for the month was 12.6 °C which is 1.4 °C
above the 1961-90 normal of 11.2 °C and is in the well
above average category.
Others:- 2000/12.1, 1999/12.9, 1998/13.1 °C.
England and Wales Rainfall (series begins in 1766).
The total for the month was 42.1 mm, which is 65 %
of the 1961-90 average and is in the below average category.
Others:- 2000/98.0, 1999/56.2, 1998/33.9 mm.
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| Note: Diary values are provisional based
on data available at the time. |
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