Harlech Castle (Gwynedd) weather

Headline:

Wet and windy to end the year.

This Evening and Tonight:

A dry start with some bright intervals. Rain moving steadily southwards throughout the day, continuing into the evening. Windy for all with gales possible in coastal and upland areas. Mild. Minimum temperature 5 °C.

Tuesday:

A dry start with some bright intervals. Rain moving steadily southwards throughout the day, continuing into the evening. Windy for all with gales possible in coastal and upland areas. Mild. Maximum temperature 12 °C.

Outlook for Wednesday to Friday:

Strong winds and heavy rain on New Year's Day, with travel disruption possible. Much sunnier to end the week, but also colder with sharp overnight frosts and isolated wintry flurries.

A cold start to this period, with overnight frost and a mix of snow, sleet and rain showers in the north. Milder air may make inroads from the south during the first weekend, bringing snow, rain and perhaps strong winds, but the northern extent of this is unclear and it may be that most or all of the UK remains in the colder air. The second week of January then looks rather varied, with high pressure, cold air and wintry showers more likely across the north, spells of rain and strong winds more likely in the south and an uncertain balance between these two regimes. Overall, temperatures are more likely to be below normal than above, but day to day variation is likely.

Slowly-evolving weather patterns look most likely mid-month, although the flavour of the weather depends on the balance of high and low pressure - initially it may well be a continuation of similar conditions to the week before. As we go through the month, it is possible that spells of strong wind, rain and snow may return more widely as unsettled conditions in the Atlantic start to have more influence over the UK. There are no strong signals for any significant cold snap, but day to day variation of temperatures is likely and there will probably be some cold interludes between milder spells.