Yellow warning of thunderstorm affecting London & South East England

Met Office sent this bulletin at 11-05-2025 10:05 AM BST
 
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Yellow warning for London & South East England
Thunderstorm
Between 12:00 (UTC+1) on Mon 12 May 2025 and 22:00 (UTC+1) on Mon 12 May 2025

Headline

Scattered thunderstorms could lead to some flooding and disruption in places on Monday.

What to expect

  • Spray and sudden flooding could lead to difficult driving conditions and some road closures
  • Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services
  • There is a slight chance that power cuts could occur and other services to some homes and businesses could be lost
  • There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds

What should I do?

Issued: 09:59 (UTC+1) on Sun 11 May 2025

Further Details

Scattered showers and thunderstorms are expected to develop on Monday afternoon. Whilst these will be fairly fast-moving, rain may be intense for short periods of time and produce 20-30 mm in less than an hour, with 40-50mm within 1-2 hours in one or two places where thunderstorms grow larger. Lightning, hail and gusty winds will be additional hazards. Showers and thunderstorms will ease through the evening.

What Should I Do?

Consider if your location is at risk of flash flooding. If so, consider preparing a flood plan and an emergency flood kit.

Prepare to protect your property and people from injury. Before gusty winds arrive, check to ensure moveable objects or temporary structures are well secured. Items include; bins, garden furniture, trampolines, tents, gazebos, sheds, and fences.

Give yourself the best chance of avoiding delays by checking road conditions if driving, or bus and train timetables, amending your travel plans if necessary.

People cope better with power cuts when they have prepared for them in advance. It’s easy to do; consider gathering torches and batteries, a mobile phone power pack and other essential items.

If you find yourself outside and hear thunder, protect yourself by finding a safe enclosed shelter (such as a car). Do not shelter under or near trees, or other structures which may be struck by lightning. If you are on an elevated area move to lower ground.

Be prepared for weather warnings to change quickly: when a weather warning is issued, the Met Office recommends staying up to date with the weather forecast in your area.

View full warning details and map view

Regions and local authorities affected

East Midlands

  • Northamptonshire

East of England

  • Central Bedfordshire
  • Essex
  • Hertfordshire
  • Luton
  • Thurrock

London & South East England

  • Bracknell Forest
  • Buckinghamshire
  • Greater London
  • Hampshire
  • Kent
  • Medway
  • Milton Keynes
  • Oxfordshire
  • Reading
  • Slough
  • Surrey
  • West Berkshire
  • Windsor and Maidenhead
  • Wokingham

North West England

  • Cheshire East
  • Cheshire West and Chester

South West England

  • Bath and North East Somerset
  • Bristol
  • Cornwall
  • Devon
  • Gloucestershire
  • North Somerset
  • Somerset
  • South Gloucestershire
  • Swindon
  • Wiltshire

Wales

  • Blaenau Gwent
  • Bridgend
  • Caerphilly
  • Cardiff
  • Carmarthenshire
  • Ceredigion
  • Conwy
  • Denbighshire
  • Flintshire
  • Gwynedd
  • Isle of Anglesey
  • Merthyr Tydfil
  • Monmouthshire
  • Neath Port Talbot
  • Newport
  • Pembrokeshire
  • Powys
  • Rhondda Cynon Taf
  • Swansea
  • Torfaen
  • Vale of Glamorgan
  • Wrexham

West Midlands

  • Herefordshire
  • Shropshire
  • Staffordshire
  • Stoke-on-Trent
  • Telford and Wrekin
  • Warwickshire
  • West Midlands Conurbation
  • Worcestershire