Understanding Thursday’s heavy rainfall: 18 UK areas at risk of 7cm downpours

Think of the upcoming weather as a big rainmaker moving in from the Atlantic. The Met Office has issued a yellow warning for rain that could stretch across 18 counties in England and Wales. It’s not a light shower either—forecasters warn that total rainfall could pile up quickly, with some places soaking through with tens of millimeters in a few hours, and pockets racing toward the 70mm mark in a single day. If you’ve felt the ground turn spongy before, you’ll know what I mean when I say saturated soil means water doesn’t drain away easily. Here’s what you need to know, what to expect, and how to stay prepared.

The warning is described as a 15-hour window of persistent rain. The timeline begins at 9:00 in the morning and runs through to 11:59 p.m. on Thursday, January 15. That’s a long stretch of wet weather, and with the atmosphere flipping from damp to downpour in minutes, keeping an eye on updates is a smart move. The forecast suggests widespread accumulations of 20–40mm are quite possible, with the potential for 40–70mm in a few isolated spots. In practical terms, that translates to a higher risk of surface flooding, disrupted travel, and damp interiors if drains and gullies struggle to keep pace.

What a yellow warning means for you

The Met Office uses color codes to signal different levels of risk. A yellow warning is a heads-up that rain is likely and could cause some disruption. It isn’t a guarantee of flooding everywhere, but it does indicate that conditions are favorable for localised issues such as standing water on roads, damp basements, or blocked drains. For households near flood-prone areas, this is a good time to review safety plans and ensure you’ve got essentials ready in case you need to limit outdoor activity or avoid certain routes.

Where the risk is most likely to land

The forecast points to a broad swath of the south and southwest of England, moving into the southwest Midlands and southeast Wales. Imagine a band of persistent rainfall pushing across these regions as a conveyor belt of moisture that can overwhelm drainage systems in towns and villages that haven’t seen a surge like this in a while. While the exact counties aren’t guaranteed to all experience the heaviest downpours, you should assume any location within this zone could face rain accumulation rapid enough to cause surface flooding and localized disruptions.

Understanding the rainfall numbers: what do 20–40mm and 70mm mean?

Rainfall is measured in millimeters and refers to the depth of water that would accumulate if it remained undrained. When forecasters say 20–40mm is expected widely, that means a couple of centimeters of rain by the end of the day in many places. If a small area sees 40–70mm, you’re looking at intense bursts during the morning and afternoon that can overwhelm drains and saturate the ground quickly. In practical terms, that’s enough water to cause standing water on roads, make some surfaces slick for drivers, and raise the risk of small streams or local ponds overflowing their banks. The combination of heavy rain, saturated ground, and relatively slow drainage can translate into surface flooding pockets, even if river levels don’t spike dramatically.

How to stay safe during heavy rainfall

Good preparation is your best defense against weather that takes a chunk out of your plans. Here are practical steps you can take today and tomorrow:

• Check your routes: If you commute by road, plan for potential delays due to flooded streets or road closures. Have a backup route, and allow extra travel time.
• Protect your property: Move outdoor furniture, bins, and anything that could be carried away by wind or floodwaters indoors or secure them firmly. Keep a set of sandbags if you’re in a known flood-prone area.
• Clear drainage points: Ensure gutters, downpipes, and outdoor drains are free of leaves and debris so water can flow away from your home more easily.
• Prepare indoors: Keep flashlights, batteries, and a charged phone accessible. If you have a basement or lower-level area, be mindful of potential ingress of water and have towels or sandbags handy to create a temporary barrier.
• Travel with care: If you must drive, avoid water-covered roads and do not attempt to cross flooded sections. Turn around; don’t drown is the rule of thumb when you see standing water on a road.

Protecting your heating system in flood-prone weather

Heavy rain and flood risk aren’t just a concern for outdoorsy things; your heating system can be affected too. If you live in a flood-prone area, your boiler, hot water cylinder, or radiators may be at risk from rising water levels or damp conditions. A baseload of rainwater and floodwater can introduce debris, silt, and sediment into heating pipes, reducing efficiency and potentially causing blockages. If you’re unsure how to protect your heating during a spell of heavy rain, consider enlisting professional help to assess and bolster your setup.

For those who want reliable, expert assistance, popular options include Harrow Heating and their team of engineers who can perform essential checks and ensure your system is not compromised by rain and flooding. If you suspect your heating system has taken on moisture or you’re preparing for a flood season, a professional inspection can provide peace of mind and prevent costly damage.

After heavy rain, you may also want to consider flushing and cleaning your heating system to remove sediment or debris that could have entered the pipes. A process known as Powerflush can help restore efficiency by cleaning sludge and rust from radiators and pipes. If you’re thinking about protecting your system in the long term, you can explore options with Powerflush to see whether this service is right for your home. A clean, well-maintained system runs more efficiently and reduces the risk of cold snaps leaving you in the lurch.

What to do if you’re in a flood-prone area

If you live near flood-prone zones, you’ll want a plan that you can put into action quickly. Start with practical steps like moving valuables to higher shelves or upper floors, placing important documents in waterproof containers, and ensuring pets and livestock have safe shelter. Stay tuned to official forecasts and local authority updates for flood warnings and evacuation advice. If you’re advised to stay indoors or leave your home, follow the guidance promptly to minimize risk.

Keep a close eye on the longer-range forecast as well. A heavy rainfall event can be followed by another, so staying prepared for a few days of unsettled weather is wise. Even if you’re not right in the center of the heaviest rainfall, a ripple effect can still cause surface flooding on certain roads and streets, so plan accordingly.

Travel, schools, and local services during a rain spell

Transport services and schools can feel the effects of heavy rainfall quickly. Train lines may experience delays due to water on lines or reduced visibility, and roads can become hazardous with standing water. Schools may alter start times or closures in areas where flooding blocks access or poses safety concerns. If you’re a parent or caregiver, keep a close watch on school communications and local transport updates so you can adjust your schedules promptly.

Staying informed: where to find the latest warnings

The Met Office is your primary source for up-to-date warnings and forecasts. They publish detailed bulletins, scenario updates, and practical advice tailored to the day’s weather. If you’d like a quick check of the latest alerts, you can visit the official Met Office site or sign up for their alerts to receive notices directly to your phone or email. It’s a simple way to stay a step ahead of changing conditions.

Planning ahead for winter weather: a practical mindset

Extreme rainfall is a reminder that weather systems can shift quickly, especially during the winter months when the ground is already saturated. Instead of waiting for the next warning, adopt a proactive habit. Build a small “rain readiness kit” for your home and your car. This can include a flashlight, a spare battery pack, a small waterproof bag for valuables, a first-aid kit, some non-perishable snacks, and a couple of towels in case you need to dry off after wet weather. Having this kit ready makes it easier to respond calmly if conditions suddenly worsen.

Conserving energy and preventing cold damage during heavy rain

Rain and flooding can hamper your heating and comfort, especially if power supplies are affected. If you’re able, keep your home well insulated and maintain consistent indoor temperatures to prevent pipes from freezing in cold snaps following wet spells. If you experience a power interruption, having a plan for alternative heat sources, such as a portable heater or a well-insulated living space, can help you ride out temporary outages without sacrificing safety or comfort. When in doubt about how to safeguard your heating system during and after heavy rainfall, reach out to a local professional. They can advise on best practices for your home’s layout and heating setup.

Conclusion

Thursday’s forecast paints a clear picture: a long period of rain is approaching across much of the south and southwest of England, extending into southeast Wales. With rainfall totals potentially reaching 70mm in isolated pockets and widespread 20–40mm, the risk of surface flooding is real, and travel disruptions could follow. Being prepared is the best strategy—check drains, secure outdoor items, plan alternate routes, and stay updated with the latest warnings. If you’re worried about flood-related impacts on your heating system, professional help from Harrow Heating can provide guidance and safe, reliable service. After a soggy spell, you may also want to consider a Powerflush to restore optimal system performance. Together, these steps can help you weather the storm with confidence and keep your home safe and comfortable even when the heavens open up.

Frequently asked questions

Which areas are most at risk for Thursday’s 7cm downpours?

The Met Office warns that 18 counties across England and Wales could see heavy rainfall, with the heaviest impacts likely in parts of the south and southwest of England, into the southwest Midlands, and southeast Wales. Exact locations vary, so it’s important to monitor local forecasts for your area.

How much rain is expected, and what does that look like on the ground?

Widespread totals of 20–40mm are likely, with isolated spots potentially receiving 40–70mm. In practical terms, that can translate to fast-rising puddles on roads, water pooling in low-lying areas, and a higher chance of surface flooding, especially on permeable surfaces or where drainage is blocked.

What should I do if I’m near flood-prone areas?

Keep up with official warnings, secure outdoor items, and move valuables to higher ground if flooding looks likely. Prepare an evacuation or safety plan if authorities issue further guidance. Avoid driving through flooded streets, and keep drains clear to help water drain away as quickly as possible.

How can I protect my home’s heating system during heavy rain?

Protecting heating equipment from floodwater is crucial. If you’re near flood-prone zones, have your heating system inspected by a professional, ensure outdoor units are secured, and consider higher positioning of critical components if feasible. After a heavy rain, a professional service can assess for moisture damage and debris. For expert support, you can look to Harrow Heating for specialist guidance and service. If sediment or debris entered the system, a maintenance option like Powerflush could help restore efficiency.

Where can I find the latest official updates?

The Met Office is the primary source for warnings and detailed forecasts. You can check their website for the latest status, updates, and safety advice. Local councils and emergency services also publish real-time information during significant weather events.