Info on Storm Dennis from the Met Office:

Here is a quick update from the Met Office regarding the weather we expect to see in the coming few days and into the weekend, including the potential impacts from Storm Dennis.

Headline: Further heavy rain and strong winds could lead to impacts such as difficult driving conditions, disruption to transport, structural damage, power outages and the potential for localised flooding. 

Warnings Issued:

–       Yellow WIND Warning (Very Low Likelihood of Medium Impacts) valid 1000 on Saturday 15th February to 2359 on Sunday 16th February 2020.

–       Yellow RAIN Warning (Low Likelihood of Medium Impacts) valid 1200 on Saturday 15th February to 2100 on Sunday 16th February 2020 (except north of Oxfordshire, NW Buckinghamshire or Milton Keynes).

Wednesday to Friday:

Much of today looks like being fine and dry with sunny spells but showers are expected to develop late afternoon and evening, but areas of more prolonged rain are expected to spread east overnight, giving 10-15 mm isolated 20 mm of rain.  The rain is expected to clear early on Thursday morning with a mix of sunshine and locally heavy showers spreading from the west.  The showers are expected to clear to the east late afternoon or evening with the wind easing further and turning north-westerly leading into a colder, dry night with isolated fog patches in places.  Friday will be generally fine and dry with sunny spells but a band of cloud and rain is expected to move southeast late afternoon and evening, clearing overnight.

Saturday / Sunday:

A deep area of low pressure, named as Storm Dennis, is expected to bring a spell of wet and very windy weather across the UK over the weekend. 

Saturday will be cloudy with occasional outbreaks of rain, locally heavy, moving east during the morning.  Although there may be some drier interludes, outbreaks of rain could continue through much of the rest of Saturday and Sunday.  Over the weekend we could see 20-30 mm of rain quite widely with a few isolated locations seeing as much as 40-50 mm.  This rain follows on quite quickly from the rain on Thursday and Friday so we could start to see some impacts in places.  Therefore, the Met Office have issued a Yellow RAIN Warning (Low Likelihood of Medium Impacts) for the areas more likely to see impacts, to go along with the Yellow Flood Guidance Statement, to highlight the potential for river and surface water flooding. 

The rain will be accompanied by very strong, south-westerly winds.  The wind will increase on Saturday morning and, more especially during the afternoon, with gusts of 50 mph isolated 60 mph.  The strongest winds are expected during Saturday and they are expected to gradually ease late on Saturday evening and night although some strong winds are still possible during Sunday.

The Met Office have issued a Yellow WIND Warning (Very Low Likelihood of Medium Impacts) to cover the potential impacts from the strong winds.  Impacts could include damaged or fallen treesdifficult driving conditions, disruption to transport, power outages and isolated structural damage. With the potential for fallen trees and structural damage there is risk of injuries and danger to life.  

Warnings can be found on the Met Office App and on the Met Office website at www.metoffice.gov.uk/public/weather/warnings 

Message from the Environment Agency (Thames area):

The cumulative effects of the recent rainfall are starting to have an effect on the saturated catchments. Our teams have, and will continue, to carry out flood runs to clear trash screens across the catchment, particularly where woody debris has been blown into channels. We will be actively monitoring the incoming weather and our operational staff are ready to respond to further rainfall. Should we receive the forecast rainfall on Thursday, we may recommend holding a partner telecom ahead of the weekend, as flood warnings may be necessary.   

Thames Valley: We currently have a number of Flood Alerts where flooding of low lying land is possible and where we have high groundwater levels in the Lambourn Valley.  Further flood alerts are possible if we get the higher rainfall totals on Thursday, Flood Warnings are not currently expected ahead of the weekend. 

Further Ahead:

Monday looks like being a day of sunshine and showers, although many places will remain dry, with a brisk south-westerly wind.  Although there may be some drier periods, it does look like next week will remain fairly unsettled with further rain and strong winds at times.