Becalmed.

Almost halfway through September the total rainfall for the month is 4.6mm, all of which fell on the 1st: and the average temperature is 16.1C, about 0.7C above normal for this point in the month and warmer than the average for August this year.

The last time we saw such a warm, dry start to September was in 2007 (incidentally, the first full month of operation of this weather station). In that year, the first half of September averaged 16C and we recorded just 1.4mm of rain, all on the 2nd.

It has also been remarkably calm – the total wind run so far this month is just 62.3NM, and most of that was on the 1st. In an average September we might have expected to pass the 1,000NM mark by now.

The common feature of both periods is a consistent spell of high pressure blocking Atlantic lows, but in September 2007 we had seen a wind run of 553.9NM at the halfway point – it was not nearly as calm as the last two weeks have been. In fact there isn’t another fortnight in the records here that comes anywhere near this for absence of wind.

Probably not good weather for yachtsmen or wind turbines, then, but a very pleasant start to Autumn for the rest of us.

August 2014 summary

August provided a real contrast to June and July as far as temperatures were concerned. The first two months of the summer were warm, with our highest June recorded average and second-highest for July. August 2014 produced an average temperature of 15.6C, sharing the title of coolest August with 2011.

Recorded rainfall was 94.4mm, but a fault on the weather station on 6 August means that figure is lower than it should be. The true figure is probably about 100mm, which is well above average but not unprecedented – August rainfall exceeded 100mm in 2008 and 2012.

Although a short spell of high pressure put in an appearance in the middle of the month, August was dominated by low pressure systems. The average pressure was 1011.2hPa, our second lowest August figure – the lowest was in 2008, when we also recorded 125.2mm of rain.

The remains of Hurricane Bertha passed up the Bristol Channel on 10 August, but fortunately for us this deep low pressure system hadn’t really got going when it passed – there were some gales and flooding further east. We saw a few thunderstorms, with one on the 14th producing 10.6mm of rain in 10 minutes.

While the positioning of low and high pressure areas in July often drew in warm, moist air from the south, in August we saw the opposite – a deep low pressure system passed north of the country on 18 August, and then parked itself over Scandinavia while a blocking high pressure system formed to our west. The result was a stream of polar air making it feel decidedly chilly, with a minimum of 6.1C on 21 August – in Dorset it got down to around 3C. Finally, August was quite a windy month, but there were no exceptional wind speeds.

At the end of July were heading for a record summer temperature, but August took the edge off that – the summer of 2014 has to settle for second place with an average temperature of 16.9C, against the summer of 2013 with 17.0C. The rainfall total for summer 2014 was 205.6mm (or about 211mm if we take account of the error on 6 August), which is on the high side but not exceptional.

A cool August could lose this summer its temperature record

In contrast to June and July, this August is turning out to be decidedly cool with an average temperature so far of 15.8C, about half a degree down on our normal figure and, so far, the second coolest August since the station was set up.

At 0339 today the thermometer dropped to 6.1C. If this sounds chilly for August, it isn’t actually that unusual – August 2011 saw a minimum of 5.2C, and in 2010 the minimum was 4.5C. On the other hand, we have yet to see a decent maximum temperature this month – the best we have seen so far is 23C, and every August we have recorded has managed better than that.

Our coolest August so far was in 2011, which was also our coolest summer overall – it was a singularly uninspiring season. This year is quite different, in that the current cool month follows a warm June and July – so warm that this summer is still, at the time of writing, our warmest on record with an average temperature of 17.1C. The gap is closing, though, because the average for summer 2013 was 17C. If the current run of cool weather continues and the average summer temperature drops a little further, this might turn out not to be our warmest summer after all – maybe just an equal-warmest.

Rainfall so far this month is 73.2mm, about average for the whole of August with a week and a half to go. We have seen some high August totals, though – 125.4mm in 2009 and 104mm in 2012 – so at the moment this month is nothing exceptional.

ex-Hurricane Bertha, Part II

The wind is dropping here now. Once the low pressure had passed this morning, the wind settled into the west and reached an average of around 15kts between 1400 and 1630. There were two gusts of 30kts, at 1612 and 1620.

A 30kt gust in August is unusual but we recorded a gust of the same speed in August 2009, and we saw 29.6kts in August 2012. Not quite a new record today, then, but it was the highest August gust speed for five years.  Our highest gust speed on record was 46kts in February this year.

ex-Hurricane Bertha

The low pressure system that was Hurricane Bertha passed up the Bristol Channel this morning without much drama, and the centre passed very close to us at 1030 with a minimum pressure of 990.3hPa. The barometer is now rising again, and the very gentle south-easterly breeze that we had earlier this morning is now a north-westerly and gaining a little in strength.

We have escaped most of the rain associated with this system, with only 3.4mm falling since midnight – Wales has recorded rather more. As the low moves off to the north-east we can expect the wind to pick up here later in the day.

Weather station fault – update

A check of the rain gauge this morning revealed that a spider had made its home in the gauge’s mechanism, obstructing the water flow and causing the decidedly odd rainfall measurements for yesterday and early today.  The squatter has been re-homed and the gauge is working properly again, but I reckon that the rainfall total for yesterday and today will be down by something like 5mm as a result of this little mishap.

Meanwhile, a sharp tap with a screwdriver seems to have resolved the problem with the transmitter. I’ll replace it anyway as soon as the part arrives, but at the moment it’s all systems go.

Weather station faulty

A radio transmitter in the weather station is failing intermittently and the conditions reported on the site may not be up to date. A replacement part is on the way and normal service should be resumed by the end of this week. Apologies for any inconvenience this may cause.

July 2014 summary

July will be remembered for hot, often humid, weather and thunderstorms, and it was the second warmest July on record here with an average temperature of 18.6C – a degree or so above normal but still half a degree below last year’s record-breaking July. The maximum temperature we recorded was 30.2C on the 24th, but that too was beaten by last year’s high of 31.2C. It was really just the second half of the month that was hot – the first week of July was relatively cool, and it was only towards the end of the second week that the warm weather got going.

There was a good deal of unstable weather throughout the month, with some very localised downpours. On 8 June, for example, a lunchtime thunderstorm at Weston-super-Mare, 10 miles north of this station, produced 25mm of rain in an hour while we basked in sunshine. On the same day Bournemouth was flooded by heavy rain and funnel clouds were seen in the Bristol Channel, but our total rainfall for the day was just 0.6mm.

By the middle of July we were under the influence of warm, humid air from the south. It was uncomfortably hot and sticky, with reports of thunder over much of the country. We got our turn on 19 July, starting with a thunderstorm at 0530 that brought us 9.2mm in an hour. During the day a column of thunderstorms just to our east moved steadily northwards but, although we could see the towering clouds and hear distant thunder for most of the day, there was no further significant rain until the evening.

At 1927 a very lively storm that had tracked across Dartmoor and Quantock arrived here and produced 10.6mm of rain in just 20 minutes, including 7.6mm in six minutes – one of the heaviest rainfall rates we have recorded. That deluge brought the total for the day to 22mm, more than half the month’s total of 42mm. This was the last recorded rain of the month.

By the next day the humidity had dropped appreciably, making the heat more comfortable. The following week was warm and sunny with a gentle north-easterly breeze. The north-easterly airflow was significant because it blocked the formation of a sea breeze which often keeps our temperatures in check, and from 23rd-26th July we saw daily maximum readings in the high 20s. A year-to-date high of 30.2C was recorded late on the 24th.

For the last few days of July the breeze was from the south-west, temperatures moderated and there was increasing cloud as we saw a switch to Atlantic weather systems. On the 31st there were a few drops of rain, though nothing measurable. So ended a warm and lively month.

The warmth of July has brought the average temperature so far this summer to 17.5C. If that figure is maintained during August, this could be our warmest summer since the station was set up.

Hotter still today

Ah, well – both of the year-to-date temperature records set yesterday were broken today, with a maximum of 30.2C recorded at 1706 and an average daytime (0600-1800) temperature of 24.2C.

The average temperature for this month now stands at 18.2C, which is 0.9C below the average for July last year.

Warmest day so far in 2014

As we thought might happen, this afternoon saw a new high temperature for this year with 29.6C being recorded at 1706.

It has also been the warmest day (0600-1800) so far this year, with an average temperature of 23.7C – rather an appropriate figure for the 23rd of July!

Despite the recent high temperatures, this month is not yet a match for July 2013 – the average temperature so far this month is 18C,  compared with 19.1C for last year. Probably not our warmest July ever, then, but a firm favourite for second place.

Possible temperature record this afternoon

I’m typing this at 1315 BST and the temperature is 27.8C and rising. The highest temperature seen to far this year is 29.1C at 1643 on 17 July, and our all-time high is 31.2C on 19 July 2013 – just over a year ago.

There is a gentle north-easterly breeze today which, so far at least, has prevented a sea breeze from forming. The sea breeze is usually a limiting factor on our high temperatures, and it is when the cooler air from the sea is blocked by an offshore breeze that we see our highest temperatures.

So – keep an eye on the web site this afternoon. It seems quite possible that this year’s high of 29.1C will be exceeded. Beating the all-time high of 31.2C is less likely because the heat is already causing some cumulus clouds to form, but you never know.

While I was typing this, the thermometer topped 28C – it’s going to be a warm one.

Warmest day of the year so far

The temperature reached 29.1C at 1643 today giving us a new high for this year, and average temperatures for last night (1800-0600) and today (0600-1800) were also new highs for this year with 18.0C and 23.1C respectively.

These figures are not exceptional for July – we have topped 29C for five out of the last seven years, and the average so far this month of 17.2C is well within the normal range. It is a year ago almost to the day – the 19th July 2013, to be exact – that we recorded our all-time record high (for this weather station) of 31.2C. We saw a daytime average of 25.8C on 18 July last year, so we can see that today’s figures are some way off being record-breakers.

Still, it’s good so see some proper summer warmth. If the forecasts are right they may soon be followed by some proper summer thunderstorms and that too is a repeat of events last July.

June 2014 summary

June this year saw some big contrasts in the weather. It was a warm month, about 1.1C above normal for the time of year and the warmest June yet recorded here with an average temperature of 16.4C. The highest temperature was 26.1C on 23rd June, which is by no means a record but still a respectable high.

It may have been warm, but June was also wet. The total rainfall of 69.2mm was well above average for June, but what makes the total more remarkable is that almost two thirds of it fell on two days, with 21.6mm recorded on the 4th and 20.6mm on the 27th. That makes those two days the second and third wettest June days on record here. On the other hand there was a two week period, from the 10th to the 25th inclusive, when no rain was recorded at all. So, a very mixed month – unusually warm for two weeks in the middle of the month, but some exceptional rainfall at each end.

June began under the influence of Atlantic lows, with a particularly complex and slow-moving depression bringing prolonged rain on the 4th. Three days later a large depression south-west of Ireland drew warm, moist air up from the south, which generated a lively thunderstorm early on the 7th – as the storm passed over there was a 3hPa increase in barometric pressure in the space of 10 minutes.

By the 10th a high pressure system had formed over the UK and this soon moved off to a point to the south west of Ireland, where it stayed until the 23rd. This high blocked any more Atlantic lows from reaching the south of the country, pushing them to the north of the UK and bringing us a spell of dry, sunny and warm weather – just right for hay-making. The temperatures recorded here were often tempered by sea breezes and so were not quite as high as those seen further inland; but we regularly got into the mid-20s and, towards the end of the dry spell, we saw that reading of 26.1C.

The high pressure retreated back to the Azores from the 23rd, allowing the Atlantic weather systems to return. A complex low brought another spell of prolonged rain on the 27th and there was a good deal of cloud, but the month ended with the sun putting in a welcome appearance on the 30th.

Overall, there was something for everyone – some proper summer weather but not too dry, and some thunder and lightning to liven things up.

Warmest day of the year so far

Today was our warmest day (0600-1800) so far this year with an average of 21.1C, and at 1559 we also recorded the highest temperature to far this year at 25.8C.

The next couple of days are likely to be warm as well, so we may see these records broken again soon.

 

Update 23 June 2014

Today’s high was 26.1C, with an average daytime temperature of 22C – so a little warmer than yesterday on both counts.