Referendum Day, 23rd June 2016.

dust

 

Torrential rain played havoc with traffic and caused local flooding as severe thunderstorms dropped a month's worth of rain in less than an hour. East Anglia and Southeast England bore the brunt of the storms. Very warm, moist air from the Bay of Biscay provided the energy for these storms, which became more intense towards the latter part of the day and into the early evening.
Whilst we are all accustomed to short sharp showers, the nature of these storms meant that they were not only heavy, but also long lasting. The graph of rainfall rate (mm/h) shows the peak event at Weatherquest, located at the Enterprise centre on the UEA campus in Norwich, during the evening. The times are labelled in utc, or 1 hour behind BST, so roughly between 8.23pm and 8.58pm giving 48mm in 35minutes. The peak rate exceeded 200mm/h, which does happen in heavy showers, but usually only for a minute or two. On this occasion, rates maintained at near or above 100mm/h for over 30 minutes.








The fundamental problem with this type of event is that even the best drains would be hard pressed to shift such a huge volume of water in such a short period of time and temporary flooding is almost inevitable. To give some idea of the scale of storms such as these, the tops of the thundercloud may have reached higher than 45,000ft from a 5,000ft base, so 40,00ft tall (7.5miles) and with updrafts within the cloud of around 100mph, it's no wonder such huge quantities of water can be held aloft.

Jim Bacon  24th June 2016

dust

Thundery start to June

June so far has provided several days with thunderstorms across parts of the British Isles thanks to a rather slack pressure pattern in humid air - meaning on many days, strong June sunshine heated this humid air to create enough instability for scattered thunderstorms to develop, especially in areas where light winds converged (came together, such as along a sea breeze front) or in areas where hills/mountains are present to provide that bit of extra lift. This led to multiple days with slow-moving torrential downpours causing some local but significant flooding problems, and in some locations on more than just one day.

The map below uses lightning data from the Meteorage detection network, interpolated onto a 6km grid, to calculate the number of days that have produced lightning through this month so far (up to the 19th). The most active spot in the country appears to be around Corby in Northamptonshire with at least 5 days of thunder so far, with a similar level of activity also noted between Buckingham and Silverstone. These areas usually have around 2-3 thunder days in an 'average June', and so have already witnessed twice as many thunder days than normal.




If your work or business is sensitive to lightning strikes, or other hazards associated with thunderstorms (such as strong winds, hail or flash flooding) then Weatherquest can help - contact us to find out how we can be an umbrella for your business...

Dan Holley  20th June 2016