© Environment Agency 2020
www.gov.uk/environment-agency
All data are provisional and may be subject to revision. The views expressed in this document are not necessarily those of the Environment Agency. Its officers, servants or agents accept no liability for any loss or damage arising from the interpretation or
use of the information, or reliance upon views contained herein.
Weekly rainfall and river flow summary
Weekly bulletin: Wednesday 13 to Tuesday 19 May 2020
Summary: The past week has been very dry across most of England. River flows have decreased at the majority of sites we report on, and are classed as notably low or lower at a third of sites.
Rainfall
It has been another dry week across most of England, with rainfall totals ranging from less than 1mm in central, east, south-east and south-west England to 5mm in north-west England (Table 1 and Figure 1). Cumulative rainfall totals for May ranged from 5% of the monthly long term average (LTA) in south-east England to 16% in north-east England (Table 1).
River flow
River flows have decreased at more than four-fifths of the key sites that we report on, compared to the previous week. The latest river flows are classed as normal or lower, for the time of year, at the vast majority of sites. A third of the sites we report on are classed as notably low or lower, with most of these sites located in north-east, north-west and south-east England (Figure 2).
Outlook
Thursday is likely to remain dry and warm for many parts of England, but with some scattered, showery outbreaks moving eastwards, and the possibility of thundery downpours in south-east and east England. Early on Friday, rain is expected to move across all parts of England, followed by showers through the weekend, which will be heaviest and most frequent in north England. Monday and Tuesday are expected to see a return to more settled conditions.
Author: National Water Resources Hydrology Team
Geographic regions
Latest Week:
13 to 19 May 2020
Latest month to date:
May 2020
Last month: Apr 2020
Last 3 months: Feb to Apr 2020
Last 6 months: Nov 2019 to Apr
2020
Last 12 months: May 2019 to Apr
2020
Total (mm) Total (mm)
% LTA Total (mm)
% LTA Total (mm)
% LTA Total (mm)
% LTA Total (mm)
% LTA
north-west 5 11 14 21 30 388 159 744 123 1,549 129
north-east 4 10 16 8 14 230 124 486 113 1,080 129
central <1 4 7 27 50 206 127 468 128 1,015 141
east <1 3 6 24 51 128 98 334 113 744 124
south-east 0 3 5 43 83 211 132 502 131 912 125
south-west 0 9 13 45 73 308 133 728 128 1,302 127
England 1 6 10 28 50 232 128 522 122 1,058 128
Table 1 Latest rainfall summary information (Source: Met Office © Crown Copyright, 2020)1
1 Notes:
LTA = long term average rainfall for 1961 – 1990.
Data for the current month are calculated using MORECS (Met Office Rainfall and Evaporation Calculation System); data for past months are provisional values from the National Climate Information Centre (NCIC).
The data is rounded to the nearest millimetre or percent (except when values are less than 1).
Recorded amounts of rainfall are likely to be underestimated during snow events.
www.gov.uk/environment-agency
© Environment Agency 2020
Rainfall
4 to 10 March 11 to 17 March 18 to 24 March
25 to 31 March 1 to 7 April 8 to 14 April
15 to 21 April 22 to 28 April 29 April to 5 May
6 to 12 May 13 to 19 May
Figure 1 Weekly precipitation across England and Wales for the past 11 weeks. UKPP radar data (Source: Met Office © Crown Copyright, 2020). Note: Images may sometimes include straight lines originating from the centre of the radar, resulting from tall trees and buildings located near the radar installation affecting its performance. This does not reflect actual conditions on the ground. Crown copyright. All rights reserved. Environment Agency, 100024198, 2020.
© Environment Agency 2020
www.gov.uk/environment-agency
River flow
‘Naturalised’ flows are provided for the River Thames at Kingston and the River Lee at Feildes Weir.
Figure 2 Latest daily mean river flow, relative to an analysis of historic daily mean flows, classed by flow percentile for the same time of year2 (Source: Environment Agency). Crown copyright. All rights reserved. Environment Agency, 100024198, 20203.
2Flow percentiles describe the percentage of time that a particular flow has been equalled or exceeded compared to the historic flow record for
that site for the time of year. Flow percentiles presented relate to an analysis for the time of year and not a whole year. 3The flow sites in this report are indicator sites providing a National overview and a subset of a wider flow monitoring network.
© Environment Agency 2020
www.gov.uk/environment-agency
River flow categories Exceptionally high Value likely to fall within this band 5% of the time Notably high Value likely to fall within this band 8% of the time Above normal Value likely to fall within this band 15% of the time Normal Value likely to fall within this band 44% of the time Below normal Value likely to fall within this band 15% of the time Notably low Value likely to fall within this band 8% of the time Exceptionally low Value likely to fall within this band 5% of the time Return to summary page