19/20 October 20
A slow moving front over the east of the UK on Sunday 21 October 2001 as shown on the following synoptic chart, was responsible for bringing heavy rain to the eastern side of the UK.

The contoured map below, consists of the data which was available from the real time network on 22 October 2001.

The following rainfall information is based on data available from our real time network on 22 October 2001. Looking back at our available records for our 3 sites in Cambridge, this is the highest ever total of rainfall reported in a single 24 hour period since records began in 1900.
| Rainfall Station | Duration of rainfall on 21 October 2001 | Rainfall Amount (mm) | Return Period (years) |
|---|---|---|---|
| Cambridge, Guildhall | 18 hours - 02:00 GMT to 20:00 GMT | 90.4 | 140 |
| Herne Bay, Kent | 4 hours - 03:00 GMT to 07:00 GMT | 39.8 | 16 |
| Andrewsfield, Essex | 18 hours - 02:00 GMT to 20:00 GMT | 53.0 | 14 |
| Monks Wood, Cambridgeshire | 16 hours - 04:00 GMT to 20:00 GMT | 52.8 | 10 |
A loop of the hourly radar composites for the period from 00:00 GMT on 21 October 2001 to 00:00GMT on 22 October 2001.

Please note: The empirical relationship between radar reflectivity and rainfall rate is fixed whereas in reality this is highly dependent on precipitation type and is very different for rain and hail.