Benign bank holiday

Libby Greenhalgh gives her forecast for this weekend along the UK south coast

Forecast for 9-12 April

Easter weekend will see a mixture of weather with a high pressure system centred to the west of the British Isles dominating the general flow and a couple of weak frontal systems trundling south across the weekend providing a variety of conditions from sunshine to cloud and rain, variable winds becoming a more consistent northerly.

Friday



The start of the easter weekend will be sunny and up to April averages with regards to temperature. With a very weak gradient flow over the UK, Friday will start off with a light and variable wind in speed and direction. Across the morning the wind will slowly settle around 300-330deg in direction with an average speed of 5 knots. As we get later on in the year the promise of a sea breeze or thermal enhancement often provides the Solent with better sailing conditions but temperatures are still too low for this. A good 5degC separation is needed between the sea and land temperatures for a sea breeze. The light winds will continue through the night pushing a warm front south into the Solent by early
Saturday



Saturday will start off cloudy and wet as the frontal system dominates the south coast of the the UK. The wind will initially be around 5 knots from 330deg. Across the morning the wind will gradually strengthen to 8 to 12 knots and veer towards 360deg. The front will be slow moving, clearing the Solent around 2pm with some lingering cloud but the sun will definately be out in the afternoon. Behind the front the wind will veer to the north east and remain around 10 knots until early evening. As temperatures start to drop so will the wind.

Sunday



Sunday will be another light and variable wind day as the gradient wind drops out behind the front with a north to northeasterly 2 to 5 knots throughout the day.

Monday



Monday shows more promise with the high pressure system continuing to dominate the UK and a second frontal system pushing in from the northwest. The wind will initially be around 5 knots from the west increasing ahead of the front to on average 8 knots by midday. There will be little change across the afternoon with the front expected in the Solent in the early evening, behind which the wind will veer towards the north west.


Technical terms:
The gradient flow/wind: this is the wind indicated on a standard synoptic chart that the Met Office produce. The distance betweenthe isobars represents the wind speed and the direction is parallel to isobars. Clockwise around high pressure systems, anticlockwise around low pressure systems. The gradient wind is indicative of the wind speed and direction at 2000ft. The surface wind is backed by 30 to 40 deg from the direction and decreased dependant on the stability of the air mass.


Other websites to check out...
Latest Radar: www.metoffice.com/weather/europe/uk/radar/
Synoptic Charts: www.westwind.ch/?page=ukmb
Satellite Imagery: www.eumetsat.de/

For some actual wind and direction:
Isle of Wight - www.islandweather.co.uk/
SouthamptonWater- www.apbg09.dsl.pipex.com/met/mainframe.htm