Added 25th October 2018 20:46
Forecast Summary
As you probably know much colder than average conditions will be arriving tomorrow and last for a few days. It’ll be significantly colder than average with widespread overnight frosts and a risk of snow for northern hills. A cold front will sink south tomorrow morning giving us all a spell of rain before clearer and much colder conditions follow on later for central areas with heavy wintry showers for northern Scotland, Northern Ireland, Irish Sea Coasts and the east coast of England, from Norfolk Northwards. Parts of the A9 (Scotland), Aviemore, Braemar, could see a few centimeters of snowfall on Saturday.
Primarily showers in the areas mentioned will be wintry to the high ground, above around 1,000ft (300m) of altitude on Friday, with a mixture of rain and sleet to lower levels. However as temperatures drop into Saturday morning the snow line could drop to 150m for a time in Northern Scotland and Northern Ireland.
Away from the showers, for most central areas it will remain largely dry on Saturday allowing for a widespread frost to form. However coastal regions will experience a succession of rain and hail showers to lower levels with sleet and snow to high ground. For example, the North York Moors, Scottish Highlands, Snowdonia and hills of Northern Ireland. Some 5-10cm is possible above 300m in Northern Scotland. So some higher routes may well be affected – check before travel. Temperatures will rise during the day, especially in land away from showers to around 4-8C nationwide.
Another cold one into Sunday with a widespread ground frost in the west, however the emphasis on Sunday will be a drier day in the west with showers becoming more aligned to eastern coastal counties of England and Scotland where they could be quite persistent through Sunday, with snow restricted to high ground above 400-450 metres of height by this stage. Another cold day, with an easterly wind developing. That easterly wind will become lighter into Monday and Tuesday, allowing for further frost risk early on during both days. A good amount of sunshine will develop on Monday and Tuesday for central and eastern areas, however there is the likelihood of some outbreaks of rain in the west (Northern Ireland, Western Scotland), which starts the theme of slightly less cold, unsettled weather through next week, less of a frost risk but remaining chilly.