Strong winds and heavy rain are expected across the south east overnight and on Monday morning.
Met Office forecasts suggest a low pressure system will rapidly deepen just to the south west of the UK later today, before moving across the country to be out over the North Sea by the afternoon on Monday.
This is expected to bring gusts of 60-80 mph widely across the southern half of the UK.
Any major storm which occurs in early autumn has the potential to cause widespread severe disruption through falling trees, structural damage, transport disruption or power cuts and possibly flooding.
Frank Saunders, Chief Forecaster at the Met Office, said: "We are confident that a severe storm will affect Britain on Sunday night and Monday. We are now looking at refining the details about which areas will see the strongest winds and the heaviest rain.
"This is a developing situation and we'd advise people to stay up to date with our forecasts and warnings over the weekend, and be prepared to change their plans if necessary. We'll continue to work closely with authorities and emergency services to ensure they are aware of the expected conditions."
The storm is also expected to feature heavy rain for some parts of the country, which also has the potential to cause some localised impacts.
An Environment Agency spokesman said: "Environment Agency teams are out working to minimise river flood risk, clearing debris from streams and unblocking culverts. We will continue to closely monitor the situation ready to issue flood warnings if needed. We are supporting local authorities who will respond to any reports of surface water flooding.”
Buckinghamshire Fire and Rescue are advising motorists to take extra care on wet or flooded roads and watch out for fallen trees and other debris.
Road safety manager Keith Wheeler said: “Check local traffic reports to see if the route is clear before you make your journey, and avoid travelling during the worst of the weather if you can.
"Take great care when driving while it’s still dark in areas that you know have flooded or been affected by severe weather on previous occasions, and please don't ignore diversion and road closure signs."
Driving tips during the wet and windy weather are:
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