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| April 2002 monthly assessment issued 1 May
2002 |
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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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| Warm and mostly dry overall. A very
warm dry start, then more changeable, but still mainly dry.
Very warm again later. Unsettled, wet and windy in the closing
days of the month, with some thunder. |
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Diary of highlights
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1st - 5th As low pressure to the west
transferred to Biscay and the Mediterranean, warm or
very warm conditions became established. After a little
light rain in south-west and north-west at first, much
drier weather with good sunny periods developed in most
places.
6th - 10th The dry weather continued
as a belt of high pressure stretched itself across the
region between parent centres over Scandinavia and the
central north Atlantic. There was a stiff easterly wind
in the south at first during the 6th and 7th. Sunny
periods prevailed on most days and temperatures were
near normal.
11th - 16th Becoming changeable
but mainly dry, with some sunny periods especially in
the south-east. Conditions were mostly quiet, but weak
fronts traversed the region bringing the odd outbreak of
light rain in places. There was frost at times at night
with Shap (Cumbria) falling to -5.5 °C early on the
13th, day temperatures were around normal. Scattered
light showers affected the Midlands and eastern areas on
the 13th and 15th.
17th - 20th More unsettled
with rain at times especially in the west and
north-west, with Nantmor (Gwynedd) receiving 60 mm in 24
hours on the 18th. On the same day a band from central
Wales to south-east England gave some showers, a few
were heavy with thunder. Temperatures were not far from
normal and the sun shone between the showers. Overnight
mist and fog patches affected a few places early on the
20th.
21st - 25th Mainly settled, dry and
very warm but weak fronts in the north-west gave some
rain on the 21st. Initially hill and coastal fog
affected north-west areas and the Channel coast, with
some local mist and fog patches inland also. Thereafter
very warm, sunny weather prevailed with Enfield (London)
reaching 23.7 °C on the 23rd, the warmest April day in
the capital since 1987. Rain, heavy at times, reached
western areas later on the 25th.
26th - 30th
Unsettled, wet and windy, with gales around coasts as
vigorous Atlantic depressions crossed northern Britain.
Associated fronts brought bands of blustery rain and
showers to the region, some outbreaks were heavy with
hail and thunder especially during the 26th, 28th and
29th. It felt chilly at times and on the 29th snow fell
over high ground in the north, while Mumbles (south
Wales) reported a gust of 67 knots.
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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 8.8 °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 53.7 mm, which is 89% of the
1961-1990 average, which is in the close to average category.
England & Wales Sunshine Series ( series began
in 1961 ). The final total for the month was 189.4 hours, which is 132%
of the 1961-1990 average, which is in the exceptionally above average
category. 3rd sunniest in series, sunniest being 1984 with 217.5 hours. Also sunniest since 1990, when 204.4 hours was recorded.
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| Scotland |
| Mild and dry for much of April, but
cold and unsettled later. |
| Diary of Highlights |
High pressure was never too far away from Scotland
for most of April, giving rise to dry conditions. Spells
of warm weather alternated with interludes of near
normal temperatures. There was more rain in the second
half of the month, and during the last five days it
became cold and unsettled.
The first warm spell began soon after the start of
the month, as low pressure in the Atlantic sank south
and winds turned into the south-east. Hazy continental
air spread across Scotland, and the temperature reached
21.0 °C at Peebles on the 3rd.
From the 5th to the 7th a large anticyclone near
Finland transferred south-west to Scotland and most
parts of the country enjoyed three days of sunny
weather. There was a large diurnal range of temperature,
and on the 7th a minimum of -6.3 °C at Kinbrace was
followed by a maximum of 18.0 °C at Dalmally.
Pressure remained high from the 8th to the 11th but
weak fronts made the weather rather cloudy.
The fronts eventually cleared south-east and from the
12th to the 15th clearer, colder air covered Scotland,
with pressure remaining high. Many parts enjoyed plenty
of sunshine, with the temperature at Altnaharra falling
to -7.2 °C on the 13th and -6.1 °C on the 15th.
From the 16th to the 19th low pressure in the
Atlantic turned winds into the south. It was dry with
sunny periods for most of the time, but a front brought
cloud and rain to the south on the 18th.
South-westerly winds brought warm and humid air to
Scotland for the next few days. At first there was
plenty of rain in the west, but on the 23rd and 24th it
became drier, with the sun appearing in most parts,
especially the east. On the 24th the temperature at
Aboyne reached 20.1 °C.
From the 26th onward there was a large fall of
pressure and cold air of north-westerly origin covered
Scotland. A couple of showery days were followed by more
general bands of rain, with snow on the
hills.
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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 7.0 °C, which
is 1.6 °C above the 1961-1990 average, which is in the well above average category. 2nd warmest in series, warmest being 1987 with 7.3 °C.
Scotland Rainfall Series ( series began in 1961
). The final total for the month was 89.1 mm, which is 110 % of the
1961-1990 average, which is in the close to average category.
Scotland Sunshine Series ( series began in 1961
). The final total for the month was 138.9 hours, which is 101 %
of the 1961-1990 average, which is in the close to average
category. Sunniest since 1991, when 148.9 hours was recorded.
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| Northern
Ireland |
| This was a wet April month with above average monthly
rainfall totals recorded in all areas. Early April was however
largely dry, but conditions then turned very unsettled by
mid-month with the wettest day being the 17th in all areas.
Both day and night-time temperatures were above average, while
sunshine totals too were greater than expected for the time of
year. |
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Diary of Highlights
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1st to 4th Fronts and troughs brought bands of
rain and showery conditions, with good spells of
sunshine between showers.
5th to 10th An
elongated area of high pressure extended over the
province giving dry and sunny conditions in all areas.
Temperatures were above average by day, but clear skies
by night allowed values to fall below normal giving air
and ground frosts in many locations.
11th to
15th As high pressure slipped off to the north-east,
a frontal system tracked across the province and brought
a change to much cooler and dulerl conditions on the
11th. Rain cleared to make way for scattered showers and
good spells of sunshine on the 12th and 13th, however
these showers died away to leave largely dry and sunny
days on the 14th and 15th. Night-time temperatures fell
to some of their lowest values of the month during this
spell, giving ground and air frosts in many
locations.
16th to 18th A deep area of low
pressure in the Atlantic tracked north-eastwards on the
16th, bringing cloud and rain and cooler conditions to
all parts of the province during the early hours of the
17th. Moderate rain fell throughout the day of the 17th
and into the morning of the 18th in many areas, making
this the wettest period of the month with between 50 and
60 mm of rainfall recorded in some northern and western
parts. This system cleared western parts quite quickly
giving a mainly dry and very sunny day in parts of
Fermanagh on the 18th, however, elsewhere conditions
remained dull.
19th to 25th Scattered showers
interspersed with good spells of sunshine dominated on
the 19th, but dull and wet conditions returned on the
20th. This then brought a change to warmer conditions
with temperatures reaching highs typically between 15
and 19 °C between the 21st and 24th. Night-time
conditions were also very mild with temperatures in most
areas falling no lower than 10 °C between the 21st and
23rd. Isolated showers were recorded on the 21st and
22nd, however high pressure gave mainly dry, warm and
sunny days on the 23rd and 24th.
26th to 30th
Unsettled with bands of rain closely pursued by
scattered showers and sunny spells. The 26th proved the
brightest day during this spell, but conditions on this
date also turned much cooler. Daily maximum temperatures
failed to reach double figures in many areas during the
last few days of the month, with wintry showers and
thunderstorms recorded in a number of locations on the
30th.
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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 8.1 °C, which
is 1.1 °C above the 1961-1990 average, which is in the above average category.
Northern Ireland Rainfall Series ( series began
in 1961 ). The final total for the month was 102.0 mm, which is 153 % of the
1961-1990 average, which is in the well above average category.
Northern Ireland Sunshine Series ( series began
in 1961 ). The final total for the month was 159.4 hours, which is 109 %
of the 1961-1990 average, which is in the close to 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 9.3°C, which is 1.4°C above the 1961-90 normal of 7.9 °C
and is in the well above average category. Others:- 2001/7.7,
2000/7.8, 1999/9.4, 1998/7.7, 1997/9.0 °C.
England and Wales Rainfall (series begins in 1766). The total for the month was 47.5 mm, which is 77
% of the 1961-90 average and is in the close to average
category. Others:- 2001/100.0, 2000/142.6, 1999/75.8,
1998/130.9, 1997/23.7 mm.
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| Note: Diary values are provisional based
on data available at the time. |
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