Thursday 4th June
There were several showers during the past twenty-four hours, especially heavy mid-morning and again late afternoon, that produced a total of 10.0mm of rainfall. The variable cloud meant the temperature by day was depressed with a maximum of 19.4C at 15.40, being 1.3C below average. In fact the last three days have produced below average maxima in this unsettled period. The same could not be said of the overnight minimum of 12.1C, being 1.9C above average, due to cloud cover and a brisk west-southwest breeze logged at 03.56 early Thursday.
Thursday gave us a cloudy and breezy start to the new day. The radar display indicated a rash of showers heading our way, likely heavy late morning on a brisk westerly air stream. We are currently under the spell of a relatively deep depression, centred over Scotland, containing much moisture after its travels over the Atlantic. The surface pressure charts indicate that a trough of low pressure will be the cause of the windy and wet spell this morning. The barometric pressure at 08.00 read 995.4mb, the lowest pressure since early January.
A weather trough is an elongated region of relatively low atmospheric pressure, within a low pressure system. As the wind shifts and air converges in this area, it is forced upward, which cools, condenses, and forms clouds. Consequently, troughs consistently bring unsettled weather, including increased cloud cover, showers and occasionally thunderstorms.
Friday will be a much better day as the current low pressure system eases away, the barometric pressure is already rising rapidly, resulting in a drier and sunnier day.
The forecast pressure charts indicate that we will be under a succession of low pressure systems up to the weekend and into next week, that will continue the spell of unsettled weather. The rainfall is very welcome by gardeners and farmers alike but a damp and cool start to meteorological summer.
Today is the last image on frogs and frog spawn. Tomorrow I will start a new series from Abbotsbury Swannery, a truly wonderful place to visit at this time of year.