September 2019:
Rainfall was high, particularly in the last 10
days of the month when 113.3 mm fell. In fact the last 10 days of September
saw 162% of the whole month's 30 year average rainfall. The complete month's
rainfall was 127.5 mm which is 182.7% of the average for the month. It was
the wettest September since 137.2 mm was recorded in 2000. It was the 13th
wettest September since continuous records began 138 years ago in Bristol in
1882.
It was the wettest of any month since November 2016.
The maximum 24 hour rainfall recorded on the 24th of 26.9 mm was the highest
for any month since December 26th 2017 when 28.5 mm was recorded.
It was a sunnier than average September in Bristol and he daily maximum on
the 1st of 19.20 MJ/m2 was the highest recorded for September since this
data started in 2005. The 1 hour maximum solar radiation of 722.21 Wm/2 at
12:00 on 12th was the highest since 2013.
The average temperature for September of 16.0°C was 0.7°C above the 30
year average for the city.
The
2018 Annual summary is here:
http://www.bristolweather.org/weather2018annual.htm
For the full monthly summary please go here:
http://www.bristolweather.org/weather2019sep.htm
The
Meteorological site is situated in an urban housing area approximately one
mile to the south of the Centre of Bristol.
This area is in a district called Totterdown.
Statistical correlations with the Bristol
Meteorological Office site, that was
less than two miles to the North and was
situated on top of a City Centre office block, were generally good with
rainfall and barometric data particularly close.
The site of the station is approximately 34 metres above sea level with the
manual instruments mounted in a Stevenson screen. The screen is sited
centrally in a small concreted garden area. A Snowdon
rain gauge is mounted correctly in the ground but does not have the full open
space required around it. A Davis
Vantage Pro2 Plus automatic weather station (AWS) was
added in May 2005 and this is mounted 4 feet above a concrete shelter. The
wind data is gathered automatically from a Davis Vantage Pro2 Plus anemometer which is
sited 3.3 metres (10 feet) above the house top.
Manual observations are still taken at approximately 09:00 hours GMT every
day for rainfall and cloud cover. Rainfall manually recorded in the Snowdon rain gauge is entered for the previous day. The
wind data is constantly logged and automatically reset at 24:00 hours GMT
every day (in the summer BST -1 hour. The Davis rainfall tipping bucket was recalibrated in November 2005 and is now
consistently under 3% under recording (an improvement from installation in
May 2005 when 10% was more
typically the norm).
Since the arrival of the Davis
Vantage Pro2 Plus equipment in May 2005 temperatures, humidity and barometric
pressure are recorded from the new equipment. These figures will be more
accurate and will be taken at exactly 09:00 GMT (in the summer BST -1 hour)
as the data is now logged to a computer.
By default the Davis
equipment records every parameter for the 24 hour period 00:00 to 23:59 BST
or GMT. Data analysis will enable manual data extraction of temperatures and
rainfall to 09:00 GMT (adjusted in the summer). Due to the 0.2 mm (tipping
bucket) measurements of precipitation recorded by the Davis equipment the
Snowdon rain gauge will still be used due to its greater accuracy (see
above).