Skies will be partly cloudy at first with isolated showers, becoming mostly cloudy later with local rain and isolated storms in the mountains, inland and the north.
Hail is possible, and snow or sleet may fall on the highest peaks.
Thursday will bring intervals of cloud with isolated showers or a storm, mainly after midday, before improving late in the day. Friday will see periods of increased cloud and strengthening westerly winds.
Temperatures will remain slightly below average through Thursday, with a small rise expected on Friday.