Category: Commentary

Wednesday 20th August.
Unfortunately all contact with my station ceased at 06.29. I hope this will be corrected soon.

Update: At last a factory reset has got the station online at about 19.30 and the live update is now functioning and correct. Sadly I have, at the moment, not been able to retrieve data for the intervening 13 hours. Could have been worse!

Although there was variable cloud on Tuesday morning the sun did eventually manage to raise the temperature above average just before 14.00 with a maximum of 23.3C at 15.19 before thicker cloud arrived. This maximum temperature was just 1.2C above average. A minor trough over southwest England produced the cloudier conditions and rainfall over the West Country during the morning and areas of thicker cloud that drifted across Hampshire in the afternoon. The wind was brisk with a peak gust of 19mph that coming from the northeast took the edge off the warmth. A minimum of 13.2C was logged at 06.29 early Wednesday that had only risen to 13.4C by 08.00 thanks to the thick cloud cover that once again had drifted in from the North Sea overnight.

Wednesday revealed another cloudy start to the day with total cloud cover although a brief break just before 08.00 allowed a couple of minutes of weak sunshine. There is hope that the cloud will thin and break up as the morning progresses that should then bring us more sunshine this afternoon.

The anticyclone has moved very little over the past twenty-four hours with the pressure at 08.00 reading 1017.0mb, exactly the same as on Tuesday at that time. The pattern of the air stream will see the northeasterly continue as the air originating near Iceland travels down its eastern boundary before changing into the northeasterly around its southern periphery. The situation is as yesterday with the modest ridge of high pressure keeping the depression to the west and disturbed area over France at bay. There is no evidence at the moment of any relief for gardeners in the form of rain, even light rain, likely in the next few days.

Monday gave us a cloudy morning that, combined with the brisk easterly breeze, restricted the increase in temperature. However, around 12.30 the sun began to break through that saw the temperature rise much more rapidly reaching a peak of 21.8C at 14.16 before cloud began to drift back again. This maximum was 0.3C below my long-term average although in the strong sunshine after midday a peak UV of 6.2 was logged, which was at the top end of ‘High’. The past two nights have been similar with variable cloud originating from the breeze travelling over the North Sea that limited the loss of warmth into the atmosphere, as a result the minimum of 15.1C, logged at 06.28 early Tuesday, was 3.9C above average.

Thanks to the cloud cover, there were minimal bursts of weak sunshine on Tuesday first thing as it struggled through the variable cloud cover. As a result the temperature had only risen to 15.6C by 08.00, not least due to the wind being brisk and having backed into the northeast. The cloudier conditions will limit sunshine today but hopefully the cloud will burn back after midday to lift the temperature, after a cool start.

The high pressure has changed little in its position over the last twenty-four hours although the ridge that extends over the UK from its centre near Iceland has eased with a fall of 5mb since yesterday. However, it is still strong enough to deter any weather fronts associated with the low pressure system in the eastern Atlantic and a more disturbed area over France. This area to the south of the UK brought scattered showers over Devon and Cornwall yesterday that last night reached eastwards into Somerset. A much more intense area of heavy rain approached south Devon just after 08.00 this morning.

At the moment there is little prospect of rain this week, however, forecasters are keeping an eye out for Tropical Storm Erin that deepened rapidly yesterday in mid-Atlantic and if caught up in the Jet Stream that could steer it towards the UK and might have a major effect on our weather next week. Storm Erin is now classified as Hurricane Erin with maximum sustained speeds pf 120mph close to the Caribbean.

The sunshine was very strong for many hours on Sunday, especially in the afternoon, that resulted in the thermometer rising to 25.9C at 16.25 being 3.8C above average. However, very thin, high cloud meant the peak solar radiation was the second lowest this month with a high of 722W/ms, but we have to remember that we are almost two months past the longest day. The easterly breeze was brisk at times with the UV level rising up to the ‘High’ category again with a value of 5.5 early afternoon. The past night was less cold than the previous four nights with a minimum of 15.7C at 06.18. This was the result of initially thin cloud drifting in from the east around 23.00 and then thickening after midnight.

Monday after dawn revealed very dull conditions with a complete cover of thick cloud. This was due to the easterly breeze picking up moisture from its travel across the North Sea and will likely take a while to burn back this morning. With no early morning sunshine the thermometer only rose a fraction to 16.1C by 08.00.

The centre of the anticyclone is still close to Iceland, and will be for the next few days, so that predominantly dry and fine weather is ahead over the next few days. However, the breeze originating from a northerly quadrant near Iceland and travelling around its eastern periphery over the North Sea will mean temperatures will fall closer to the normal for August at around 22C over the next few days but as today there is likely to be more variable cloud limiting the sunshine. The southern edge of the ridge of high pressure over the UK will recede a little but continue to be the dominating factor affecting our weather this week. The barometric pressure has fallen 3mb since its peak on Saturday.

Saturday was significant for the almost extensive variable cloud cover for most of the day compared to the recent weeks, as a result the maximum was below average for the first time since the 5th with a minimum of 20.9C logged 05.52, early Sunday being -1.2C and down over 10C compared to maxima in the heatwave. The cloud that had drifted in from the North Sea overnight did not dissipate as quickly or completely as had been forecast. The day was also notable for the stiff breeze from the northeast, that combined with the moisture meant that it felt decidedly cool at times. Under clear skies the warmth fell away to reach a low of 8.3C at 05.52 early Sunday being 2.9C below average and the coolest day since the 6th.

Sunday revealed the return of the sun after dawn that had lifted the temperature to 14.7C by 08.00. The anticyclone is still in change of our weather so a fine, sunny day ahead with the breeze continuing from the east and temperatures recovering above average but no heatwave extremes.

The high pressure has withdrawn towards Iceland with a slight fall in pressure reading 1025.3mb at 08.00 Sunday but leaving a ridge over the UK. However, the air stream will continue to arrive on an easterly then northeasterly on Tuesday but a little less strong than on Saturday. It isn’t until Wednesday that the maxima return to around average for August.

The total rainfall for August now stands at 3.2mm against my 41-year average of 65.5mm with little indication, at the moment, of any rainfall over the next few days unless the forecast disturbance of France moves northwards.

Friday was the fourth day this month when the maximum temperature reached the heatwave threshold of 27C with a peak of 28.4C logged at 16.22 being 6.3C above my long-term average. Variable, thin high cloud in the afternoon limited the peak temperature as well as peak solar activity, which at 694W/m2 was the second lowest this month. During the late evening the temperature dropped steadily but just after midnight the fall began to reduce as thin high cloud arrived around 01.00 with much thicker cloud rolling in from the east around 04.30. The strengthening breeze on an east-northeast breeze collected the moisture having tracked over the North Sea, thus the minimum of 14.6C logged at 05.53 was 3.4C above average.

Saturday brought a very different start to the new day as it revealed the low cloud on a cool east-northeasterly breeze that had slowly been increasing in strength, with no sunshine. The cloud will take a while to burn back eastwards before the sun is likely to return late in the morning. The ridge of high pressure has built a little further with a reading of 1028.1mb at 08.00, very close to the highest pressure all month, so at the moment little chance of any rain for the gardens over the weekend.

The anticyclone has edged a little closer to the UK being centred over the Outer Hebrides. It will be with us for another few days resulting in subtle changes in the maximum temperatures that will slowly decline with the breeze on Sunday likely to come from the east and fall a little lighter than that on Saturday as the ridge of high pressure extends southeastwards across the UK.