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August 2004 monthly assessment issued 2 September 2004
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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 or hot for the first week with thundery showers. Unsettled for much of the month with some torrential rain. Fine in many places on the last two days. |
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Diary of highlights
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1st to 8th: Generally sunny on the 1st except in eastern coastal parts, where low cloud and mist was persistent. Over the following week, the weather became more unsettled with showers becoming widespread and thundery. On 3rd, 42.4 mm of rain was recorded at High Wycombe in an hour. It was very warm or hot and on the 7th and 8th, 31.5 °C was recorded in central London and at Northolt, while eastern coasts again had misty low cloud.
9th to 15th: The hot weather culminated in some
warm, sultry night nights and at Marham, Norfolk, a minimum
of 21.9 °C was recorded on the morning of the 9th, the
warmest night there since at least 1957. Slow moving fronts
and troughs gave an unsettled period, with prolonged heavy
thundery rain or heavy thundery showers. Wittering recorded
90.8 mm in the 24 hours to 0900 on the 10th, Kirklees 80.6
mm, with 64.0 mm falling in 12 hours, and Pembrey Sands
(Carmarthenshire) had 44.2 mm of rain in the three hours
ending 0200 on the 12th. The 14th was fine in most places
but this was only a temporary respite as Atlantic fronts
edging into south-western parts on the 15th heralded another
unsettled period.
16th to 17th: Rain pushed north-east overnight into the 16th followed by some torrential thundery downpours. On the 16th there was devastation in Boscastle (north Cornwall) due to severe flooding and at nearby Otterham 200.4 mm of rain fell in 24 hours. Lesnewth near Boscastle had 64.8 mm of rain in an hour. On the 17th the far west of Cornwall had heavy rain with 58 mm in three hours at Camborne, 64.4 mm in the 12 hours to 2100, and 31.6 mm in an hour at Culdrose, 56.2 mm to 2100.
18th to 29th: Low pressure dominated with temperatures
generally close to average. Northern England had heavy rain
overnight into the 20th. There were further thundery showers
and at Bedford 41.8 mm of rain was reported in the hour
to 1700, with a 12-hour total of 55.2 mm to 2100. North-west
England bore the brunt of the heavy rain on 25th with 41.6
mm of rain recorded at Manchester Hulme. There were a few
drier days notably the 25th and 28th while fronts cleared
south-east during the 27th. West to north-west winds following
in the wake of a low on the 28th brought a chilly feel.
30th to 31st: The 30th was rather cool in many places with fresh winds and there were some showers in the east. A ridge of high pressure on the 31st brought a fine day to most places to close the month.
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| Statistical details (using best
available data/estimates): Updated January 2005 |
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England & Wales Mean Temperature Series (series
began in 1961).
The final value for the month was 17.1 °C, which
is 1.9 °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 148.9 mm, which is 194%
of the 1961-1990 average, which is in the exceptionally above
average category. Wettest in series, previous wettest 1992
with 127.7 mm.
(For greater historical context, see EWP (Met Office Hadley Centre) - selected
station data series)
England & Wales Sunshine Series (series began
in 1929).
The final total for the month was 173.8 hours, which is 101%
of the 1961-1990 average, which is in the close to average
category.
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| Very wet in east and south. |
| Diary of Highlights
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Cyclonic spells in the middle of August generated some unusually heavy rain, especially
in areas exposed to the south-east. This culminated in a landslide
in Glen Ogle on the 18th, and Leuchars experienced its wettest
month since records began in 1922. There was also some very
warm air in the first half of the month and Aviemore recorded
its warmest night on record on the 9th. While much of southern
and eastern Scotland suffered from the mid-month deluges,
Shetland enjoyed well above average sunshine.
An anticyclone in the Norwegian Sea with a light south-south-easterly airflow over Scotland gave a fine start to the month away from the east coast. The temperature reached 27 °C at Aultbea on the 2nd.
From the 3rd to the 6th a slack pressure field covered Scotland and weak fronts gave unsettled weather with a good deal of cloud and some outbreaks of rain. Eskdalemuir recorded 65 mm on the 3rd. However, it remained warm with the temperature rising to 26 °C at Charterhall on the 6th.
Fair weather returned on the 7th and 8th with a south-easterly
wind and the temperature rising to 28 °C at Broadford
and Aultbea.
On the 9th, fronts associated with a deep depression to the
south-west of Ireland reached the south-west of Scotland and
became slow moving. Much rain fell over the southern half
of Scotland during the next four days with 48 mm at Oban overnight
on the 8th/9th, 51 mm at Strathallan on the 9th and 56 mm
at Bishopton on the 10th. Fair weather persisted in the north
with a minimum temperature of 20 °C on the 9th and a maximum
of 27 °C at Aultbea the next day.
The depression eventually cleared away to the east on the
13th and a ridge of high pressure developed to give fine weather
for a couple of days.
Low pressure in the Atlantic extended its influence over Scotland on the 15th and unsettled weather with much cloud and some outbreaks of rain returned. A deep depression developed and moved north-east across the north of England on the 18th, pushing an active front and its associated band of rain north across Scotland. The rain was heaviest in places exposed to the east and 50 mm was recorded at Loch Tay, close to the site of a landslide in Glen Ogle. There was even more rain (64 mm) in a storm at Lerwick.
The depression was followed by cool northerly winds on the 20th and a broad ridge of high pressure on the 21st and 22nd. This gave plenty of sunny weather with the temperature at Tulloch Bridge falling to -1 °C.
Unsettled and changeable conditions returned between the 23rd and 30th as two depressions passed close to Scotland, the first to the south and the second to the north. There was much rain overnight on 26th/27th with 50 mm measured at Sloy. Winds gusted to 66 m.p.h. at Kirkwall the next day.
The month ended with a ridge of high pressure giving a sunny day on the 31st with the temperature falling to 0 °C at Tulloch Bridge.
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Statistical details (using
best available data/estimates): Updated January 2005
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Scotland Mean Temperature Series
(series began in 1961).
The final value for the month was
14.5 °C, which is 2.0 °C above the 1961-1990 average, which
is in the exceptionally above average category.
Scotland Rainfall Series (series began in 1961).
The final total for the month was 188.1 mm, which is 161%
of the 1961-1990 average, which is in the well above average
category. Wettest since 1992, when 211.0 mm was recorded.
Scotland Sunshine Series (series began in 1929).
The final total for the month was 147.4 hours, which is 109%
of the 1961-1990 average, which is in the close to average
category.
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| Mostly dry and warm at first, soon turning unsettled. Often warm and humid - several significant rainfall events. |
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Diary of Highlights
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The first week, apart from some well scattered showers, was often dry and warm with maximum temperatures frequently in the range 23 to 25 °C.
From the 8th onwards, the weather became more unsettled. The remains of ex-hurricane 'Alex' produced a wet day in places with 10-15 mm of rain in many places and 30 mm or more over some parts of County Down.
The second week continued very humid with some very warm sunshine at times but
also with some locally heavy, thundery showers. Thundery showers
produced 42 mm of rain at Hillsborough, County Down on the
10th.
By the 16th another ex-hurricane, this time 'Bonnie' was making its presence felt, and this low pressure area dominated for the next two or three days. Heavy, thundery downpours occurred on the 17th and Londonderry city centre was badly flooded. Further heavy spells of rain followed on the 18th with a further 20-25 mm of rain in places. Two day rainfall totals from this system brought 35 mm or more in some areas.
The 20th and 21st were temporarily drier and brighter with some good sunny spells and pleasantly warm by day though much cooler at night.
Wet weather resumed on the 22nd & 23rd with a further 25-35 mm in some eastern areas, this time courtesy of ex-hurricane 'Charley'.
By the 24th, the remnants of this low lay right across Northern Ireland and torrential thundery downpours brought flooding to parts of Down and Antrim. 31 mm was recorded in just 90 minutes at Ballyclare on the morning of the 24th.
The remainder of the week was rather unsettled with further
rain or showers at times and it was occasionally quite breezy,
although there were some brighter and drier interludes for
most areas. On the night of the 30th into the 31st clear conditions
combined with a northerly airflow allowed temperatures to
dip quite low, with Katesbridge recording a minimum of 0.8
°C.
The localised nature of thunderstorms during the month meant there were large variations in rainfall amounts, in some parts these thunderstorms gave nearly 50% of the monthly average in just a couple of hours.
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Statistical details (using
best available data/estimates): Updated January 2005
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Northern Ireland Mean Temperature Series (series
began in 1961).
The final value for the month was
15.3 °C, which is 1.6 °C above the 1961-1990 average, which
is in the well above average category.
Northern Ireland Rainfall Series (series began
in 1961).
The final total for the month was 114.1 mm, which is 120%
of the 1961-1990 average, which is in the above average category.
Wettest since 1992, when 171.9 mm was recorded.
Northern Ireland Sunshine Series (series began
in 1929).
The final total for the month was 134.1 hours, which is 99%
of the 1961-1990 average, which is in the close to average
category.
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| Homogeneous
series based upon selected station data: |
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Central England Temperature (series begins in
1659).
CET
Index
England and Wales Rainfall (series begins in 1766).
EWP
Index
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| Note: Diary values are provisional based
on data available at the time. |
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