The example below details an event that happened in Cornwall. It would have generated an amber warning of rain with the new warning service.
Weather situation on 17 November 2010
A deep area of low pressure in the Atlantic swept bands of heavy rain across much of south-west Britain on 16 and 17 November 2010. The heaviest rain occurred overnight in Cornwall. The rain was particularly intense between 0400 and 0700 GMT on 17 November.
Rainfall totals for the period 2100 UTC on 16 November to 0900 UTC on 17 November included:
Heligan (near Mevagissey)
Stoke Clether (Bodmin Moor)
The very intense rainfall resulted in rapid surface water run-off. The short, steep, rapidly responding nature of Cornwall's river catchments make them particularly susceptible to flooding from this type of intense rainfall.
A flooded street
Based on the new warning system the following assessments would have been made:
This would have resulted in a amber warning for rain: