Solent Forecast

Libby recommends factor 20 this weekend and some interesting possibilities

Forecast for 29th-30th March.

Saturday will see a risk of rain in the morning with cloudy conditions providing a light 6-10 knot north north-easterly breeze. Back to the factor 20 on Sunday as a high pressure ridge moves in providing a northearly wind of roughly 10 knots that will build across the day. High Tide Portsmouth Saturday 0920, Sunday 1006.

The weekend will see a change in the weather between Saturday and Sunday as a change in the pressure system from low to high occurs. The relatively weak low pressure system that will provide Friday with wetter more cloudy conditions will slowly move off on Saturday, late morning early afternoon. This will allow a ridge of high pressure to influence the rest of the weekend.

Saturday will provide cloudy conditions with a shallow frontal system pushing across the south coast by 0900 will mean the wind will veer from the north. An occluded front strung out across the country threatens the rest of the afternoon but looks set to dissipate by 1400 hours.

Saturday will see the battle of the weak low pressure centred over Brittany being squeezed out by a ridging high pressure system from the southwest of the UK. This will provide light north northeasterly winds around 020˚ with a wind strength of 6-10 knots, at most, on the synoptic scale.

The synoptic chart attached shows the regions of rain and therefore cloud by the shaded pink areas. It can be seen that on midday Saturday there is a band of rain associated with a weak low pressure system sitting just on the edge of the Solent. The high pressure ridge should keep this at bay providing Saturday with dry sunny spells and a maximum temperature of 13˚C.

With cloudy conditions forecast there will be reduced chance for the sun to heat the land and start the sea breeze cell. Should the clouds break and clear one can expect the wind to veer more easterly to around 090˚ with the wind strength building to maximum of 15 knots between 1300 and 1400 hours.

Sunday will see the high pressure ridge dominate the day providing clear skies and a strong chance of a sea breeze. The gradient breeze will be northeasterly 050˚ of 8-10 knots assisting the sea breeze cell development. The wind strength will build across the morning as the land heats up with maximum wind strength towards 20 knots in the early afternoon. The direction will veer in a similar fashion to last week by between 30˚-50˚ from the initial wind direction settling around 100˚ by 0900 for the day.

Should the day cloud over the wind will begin to decrease and back towards the north otherwise this change is not expected until the daytime temperature begins to decrease around 1600 hours.

It is worth keeping your eye on the cloud for the weekend, check out the Dundee Satellite Station at www.sat.dundee.ac.uk , as this will be the key to wind strength and direction in terms of thermal enhancement and sea breeze cell.