Torrential rain is due to hit parts of Wales on Sunday and forecasters are warning of possible flooding, power cuts and travel disruption.
The Met Office has updated its severe weather warnings for thunderstorms across the country on Sunday, Monday and Tuesday giving more specific details of the areas they are expected to hit.
Meteorologist Derek Brockway said the outlook is for "large hail, lightening and gusty winds".
Temperatures reached 28C in Cardiff on Friday - well above the June average high of 19.8C.
Mr Brockway said Saturday would feel "fresh" and "comfortable" but hot and humid air is expected to arrive from the south.
According to the Met Office, thunderstorms may develop in Wales from 7pm on Sunday, bringing lightening and torrential rain.
Forecasters are warning there is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from flood water or lightening strikes.
The severe weather warning highlights the chance that train and bus services could be cancelled in areas affected by flooding or lightening strikes.
It adds there may be road closures and difficult driving conditions due to spray and sudden flooding. There is also a chance of power cuts.
Many areas are expected to be hit by spells of rain, which may turn heavy and thundery, on Sunday evening.
Sunday's severe weather warning from 7pm until midnight covers Conwy, Denbighshire, Flintshire, Gwynedd, Isle of Anglesey and Wrexham
Forecasters say between 20mm and 30mm of rain may fall in some places within an hour.
They write: "Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services.
"Spray and sudden flooding could lead to difficult driving conditions and some road closures. There is a chance that power cuts could occur"
The yellow weather warning in place for Monday now only covers the eastern edge of Wales
What they say:
- 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
- There is a small chance of fast flowing or deep floodwater causing danger to life
Tuesday's warning covers all of south Wales and part of north east Wales
What they say:
- Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services
- Spray and sudden flooding could lead to difficult driving conditions and some road closures
- There is a slight chance that power cuts could occur and other services to some homes and businesses could be lost
