The 55-year-old urged viewers to be careful when travelling today as visibility will be very poor in places.
She said: “Some of the fog is dense and it’s dangerous when it’s patchy because you run into it suddenly.”
Northern Ireland, Wales, Scotland, East Anglia, Lincolnshire and the Midlands will be particularly foggy.
In Northern Ireland there will be cloud this morning with patchy fog in the south west.
The west of England is likely to see the most sunshine although some fog won’t lift, leaving the area grey.
However, in the east it won’t be cold but the area will see light rain in places.
On Friday, frost and fog patches will remain until it lifts into low cloud later in the day.
It will be drier in Northern Scotland, parts of Wales, Dorset and south west England, with the temperatures between six and eight degrees.
At the start of the weekend a weather front will travel across the UK bringing rain.
Sunday is expected to be brighter and largely dry, although it will be cloudy and breezy.
BBC Breakfast continues tomorrow on BBC One at 6am.
