Thunderstorms: West Sussex County Council has issued an Amber Severe Weather Warning valid from 12.15 am to 11.45 pm for tomorrow (Saturday July 19th).
We will see heavy, thundery showers developing as we move into this evening. The showers could be torrential at times and accompanied by frequent lightning, large hail and strong gusty winds leading to significant impacts in places. We could see 10-20mm of rain quite widely overnight with some places seeing 30-40mm. It is possible that in particularly heavy showers some places could see 50-75mm in 3 hours, 30 mm or more in an hour. There is still some uncertainty about the exact location of the heaviest showers.
When this first area of showers has cleared there will be a dry period with good sunny spells during the morning but as the temperatures rise further heavy showers and thunderstorms will develop during the afternoon. These showers are expected to clear during the evening to leave a rather cloudy but dry night.
The impacts of the storms may include:
- Surface water flooding.
- Flooding on fast responding urban river catchments.
- Power outages due to lightning strikes.
- Poor driving conditions.
- Disruption to transport and outside events.
Please take extra care when driving and leave plenty of extra time for journeys.
Heatwave: There is a 60% chance of temperatures reaching 31°C during the day and 16°C overnight today (Friday July 18th) tomorrow. The highest temperatures are likely today followed by a very humid night. Heavy thunderstorms on Saturday will lead to slightly lower maximum temperatures, but it will still be very humid.
The very young, the elderly and the seriously ill are the groups who are particularly at risk of health problems when the weather is very hot. In particular, very hot weather can make heart and breathing problems worse.
Please follow this advice to keep cool and comfortable and reduce health risks:
- Shut windows and pull down the shades when it is hotter outside. If it’s safe, open them for ventilation when it is cooler.
- Avoid the heat: stay out of the sun and don’t go out between 11am and 3pm (the hottest part of the day) if you’re vulnerable to the effects of heat.
- Keep rooms cool by using shades or reflective material outside the windows. If this isn’t possible, use light-coloured curtains and keep them closed (metallic blinds and dark curtains can make the room hotter).
- Have cool baths or showers, and splash yourself with cool water.
- Drink cold drinks regularly, such as water and fruit juice. Avoid tea, coffee and alcohol.
- Stay tuned to the weather forecast on the radio or TV, or on the Met Office website.
- Plan ahead to make sure you have enough supplies, such as food, water and any medications you need.
- Identify the coolest room in the house so you know where to go to keep cool.
- Wear loose, cool clothing, and a hat if you go outdoors.
Check up on friends, relatives and neighbours who may be less able to look after themselves.