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| July 2004 monthly assessment issued
4 August 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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| Changeable at first with some
thundery rain. More settled later with some very warm and
humid air becoming established towards the end of the month.
A notable wet, windy and sometimes cool spell of weather on
the 7th and 8th. |
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Diary of highlights
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1st to 4th An area of low pressure drifted across
the north of the United Kingdom, giving cyclonic conditions
to many parts of England and Wales. This translated to
a period of sunshine and showers. Some showers were heavy
and thundery with 42.4 mm recorded at Boscombe Down in
Wiltshire on the 2nd. Another area of low pressure affected
southern England on the 4th giving further showery rain,
locally heavy and thundery.
5th and 6th High pressure built in from the west
to give most places long sunny periods. A few showers
affected more eastern parts of England, some thundery.
In the sunshine central London recorded a temperature
of 25 °C on the 6th.
7th to 11th A deepening area of low pressure spread
from north-west France into England and Wales, giving
some unseasonably wet, windy and sometimes thundery weather.
This was followed by a showery north-westerly air stream.
Wittering (near Peterborough) recorded 108.0 mm in the
24-hour period to 5 p.m. on the 8th, an exceptional amount.
Gusts in exposed parts of south-west England and south
Wales exceeded 60 m.p.h. Some very cool temperatures were
recorded in the rain; Sennybridge in Powys recorded just
9.6 °C on the 8th.
12th to 18th A ridge of high pressure developed
across the south giving quieter conditions. As warmer
and more humid air became established, coastal fog became
a feature. A frontal wave developed on the northern flank
of the high on the 14th giving rather cloudy and sometimes
wet conditions, especially across Wales. The front and
its associated waves then spread east on the 17th to give
East Anglia and south-east England some heavy and thundery
rain. The most violent thunderstorms were in Essex and
marble-sized hail was reported. Holbeach (Lincolnshire)
recorded 25.2 mm in one hour in a heavy shower on the
18th.
19th to 23rd A fairly slack pressure pattern then
became established giving some warm sunny spells, but
also a scattering of showers, some heavy and thundery;
Scampton in Lincolnshire recorded 28.6 mm in just one
hour on the 22nd. A high of 27.6 °C was reached in
central London and Charlwood on the 22nd.
24th to 31st The last week of the month saw high
pressure building across all parts of England and Wales.
Weakening weather fronts drifted into the high from the
north at first, giving cloudier and occasionally wet conditions,
especially further north. Later in the period the high
began to drift eastwards drawing up some very warm and
humid air from the Continent. A temperature of 30.1 °C
was achieved in central London on the 29th, the warmest
day of the month. A weakening cold front spread in from
the west on the 29th to give some wet weather in northern
England. Misty low cloud affected eastern coasts at the
very end of the month.
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| Statistical details (using best available
data/estimates): Updated November 2004 |
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England & Wales Mean Temperature Series (series
began in 1961).
The final value for the month was 15.4 °C, which is
the 1961-1990 average, which is in the close to average
category.
England & Wales Rainfall Series (series began
in 1961).
The final total for the month was 68.5 mm, which is 110
% of the 1961-1990 average, which is in the close to average
category.
England & Wales Sunshine Series (series began
in 1929).
The final total for the month was 166.0 hours, which is
91 % of the 1961-1990 average, which is in the close to
average category.
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| Unsettled but dry. |
| Diary of Highlights |
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Unsettled westerly weather dominated the month with high
pressure not making an appearance until the last week. However
there were no major episodes of rain and days of frequent
or heavy showers were rare. Consequently, over Scotland
as a whole, it was a dry July.
During the first five days a centre of low pressure moved
slowly east and crossed the north of Scotland. The weather
was rather cool with a good deal of cloud and some showers,
but there were also sunny intervals.
Relatively high pressure covered the country between the
6th and 8th giving emphasis on the sunny periods rather
than the showers. Under clear skies and light winds the
temperature fell to freezing at Altnaharra and Tulloch Bridge
on the morning of the 8th.
A light northerly airflow affected Scotland from the 9th
to the 11th, bringing grey skies but only a little rain.
The changeable westerly weather continued from the 12th
to the 19th. There were a couple of spells of general rain,
but for much of the time there were sunny intervals and
scattered showers.
More disturbed conditions affected Scotland from the 20th
to the 24th with low pressure to the north-west pushing
south-westerly winds and troughs across the country. There
was 40 mm of rain at Sloy on the 20th and 33 mm at Dalmally
on the 24th. The remaining days were predominantly showery.
High pressure prevailed during the last week of July, bringing
much fine weather. Air of cold origin gave sunny periods
on the 25th and 26th and these conditions returned for the
last two days of the month. Between these spells warm and
humid air with more cloud covered the country, with the
temperature reaching 25 °C at Charterhall on the 29th.
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Statistical details (using
best available data/estimates): Updated November 2004
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Scotland Mean Temperature Series (series
began in 1961).
The final value for the month was 12.8 °C, which is
0.2 °C above the 1961-1990 average, which is in the
close to average category.
Scotland Rainfall Series (series began in 1961).
The final total for the month was 75.8 mm, which is 79 %
of the 1961-1990 average, which is in the below average
category.
Scotland Sunshine Series (series began in 1929).
The final total for the month was 132.3 hours, which is
93 % of the 1961-1990 average, which is in the close to
average category.
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| The month overall was a disappointing high
summer month with mean temperatures just below the long term
average. Indeed it was only the last two days of the month
when sunny skies and temperatures into the low twenties occurred
Province-wide. |
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Diary of Highlights
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The first week was often showery with some heavy and thundery
showers in places and a funnel cloud was reported at Castle
Espie on the 1st. A total of 15 mm of rain occurred in places
during the first two days. With winds from a north-westerly
quarter, maximum temperatures were frequently down to between
16 and 18 °C. The 7th however was drier, brighter and
warmer everywhere. The showery theme resumed for the next
few days though showers were more scattered than during
the first week. Clearing skies at night allowed night-time
temperatures to fall well into single figures with local
grass frost and a night minimum temperature of just 1 °C
at Katesbridge, Co Down on the morning of the 10th.
The 12th started cloudy with some showery rain but became
brighter with sunny spells by afternoon and this persisted
well into the 13th. Cloud and rain however returned by the
evening of the 13th.
The third week of the month was unsettled and still rather
cool with some showers or longer spells of rain. The 20th
especially was almost Autumnal with gusty winds accompanying
widespread rain. A thunderstorm late on the afternoon of
the 20th saw Enniskillen receive 25 mm of rain in just two
hours. The 21st - 24th was a brighter period with some sunshine
and just a few showers, but cloud and rain associated with
advancing warmer air occurred between the 25 and 27th. Sunnier
spells on the 28th allowed temperatures to reach a very
warm and humid feeling 21 to 23 °C. Further rain affected
all areas on the 29th.
High pressure finally arrived for the closing two days
of the month with sunny skies for most on the 30th and 31st.
The months highest temperature of 24 °C was recorded
at Newfordge Belfast on the 31st.
Rainfall overall was slightly below normal in the east
and well below normal over parts of Co Down with only 66%
of average at Silent Valley. Parts of the west were wetter
and Enniskillen saw 154% of average though this was mainly
due to some local thundery downpours on the 20th.
Sunshine overall was around average although parts of Co
Londonderry had 117% of the long term average.
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Statistical details (using
best available data/estimates): Updated November 2004
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Northern Ireland Mean Temperature Series (series
began in 1961).
The final value for the month was 13.8 °C, which is
0.2 °C below the 1961-1990 average, which is in the
close to average category.
Northern Ireland Rainfall Series (series began in
1961).
The final total for the month was 62.8 mm, which is 88 %
of the 1961-1990 average, which is in the close to average
category.
Northern Ireland Sunshine Series (series began in
1929).
The final total for the month was 132.6 hours, which is
95 % 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: All values are provisional based on
data available at the time. |
