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.

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.