The Met Office says isolated heavy, and possibly severe, thunderstorms are expected to develop on Friday evening across parts of Wales.
It says some torrential downpours are possible leading to localised surface water flooding.
Hailstorms and frequent lightning are also possible hazards.
It says the public should be aware that there is a chance of some very localised significant disruption.
The yellow 'be aware' warning is in force from 7pm to midnight.
The Met Office has issued a yellow 'be aware' warning for snow and ice across much of Wales for the weekend.
The warning has been extended from Friday where there was snowfall in north and mid Wales causing travel disruption and hazardous driving conditions.
Snow showers are also expected on Sunday.
The Met Office said there's the potential for disruption throughout this period due to the accumulating snow and ice but also with temporary blizzard conditions leading to very difficult driving conditions.
A leading Welsh tourism operator has criticised the Met Office for scaring away visitors with their warning of a severe storm. Wales escaped the worst of the threatened damage with the bad weather hitting the south West England instead.
As the downpour hit Wales - hundreds of students ignored the storm to go on a Cardiff pub crawl and dance in the rain.
University freshers paid little attention to to the severe weather warnings and went out drinking across the city centre in fancy dress as part of a series of Carnage events.
And torrential rains and winds in excess of 90mph on Sunday night did nothing to damped their spirits as they took to the streets in short skirts and cropped tops.
The students wore white Carnage T-shirts - and there wasn't a raincoat or umbrella in sight.
Council workers were out in the city this morning clearing roads after heavy rainfall last night.
Although Wales avoided the worst of the storm, 6 flood alerts remain in force across the country.
One vehicle became stuck in deep water on Penarth Road in Cardiff and the road remains closed as workers attempt to clear the area.
Local bus services are diverted.
The M4 Second Severn Crossing has now reopened after being closed overnight due to high winds.
The M48 Severn Bridge remains closed after the Highways Agency and police forces in England and Wales reviewed the situation overnight.
Even though the Second Severn Crossing is now reopened, tailbacks will impact on the early Monday rush hour.
Gwent Police are urging people to plan ahead.
There are currently 5 flood warnings across Wales:
Gwynedd, Denbighshire: Upper Dee Valley from Llanuwchllyn to Llangollen including
Powys: Vyrnwy Catchment.
Powys, Merthyr Tydfil, Rhondda Cynon Taf, Cardiff: River Taff.
Powys, Shropsire: Upper Teme upstream and including Knighton.
Wrexham, Cheshire: Lower Dee Valley from Llangollen to Trevalyn Meadows.