April 1998

After a cool first half - the mean daily temperatures falling to 2° to 3° Celsius below normal from the 10^th to 15^th - a milder than usual second half resulted in the mean temperature for the month as a whole being just 0.3° Celsius below normal. Rainfall was 90.7% of normal – and would have been much lower except for a short wet spell from the 20^th-24^th, with 14.8 mm of rain falling on the 23^rd. Sunshine was well above average with 127.0% of the usual April total, the only ‘dull’ periods being the 3^rd-6^th and 22^nd-24^th. The mean pressure for the month is the lowest recorded for any April since 1974 (previous lowest 1005.6 mb, 1977).

The month began with near average temperature and fresh NE to E’ly winds and a few showers – the wind increasing to gale force on the 3^rd.

Low pressure soon became established over the UK and southern North Sea maintaining the cool and showery NE’ly airflow over the Northern Isles – with winds again increasing to gale force on the 12^th accompanied by frequent wintry showers.

Shortly after mid-month high pressure built over the North Sea bringing a sunny spell and milder conditions to the North of Scotland. Low pressure then became established to the west of the British Isles – with fresh SE’ly winds bringing cloudy conditions with outbreaks of rain and drizzle to Orkney and Shetland.

Towards the end of the month this low pressure drifted east across the British Isles and, with a ridge of high pressure then building north-east across Shetland, the month ended dry and sunny.