Useful rain but not enough for the gardeners!

There were two areas of rain on Saturday, the heaviest late afternoon, that produced 4.3mm of rainfall.

Both maximum and minimum were well below average with figures of 18.2C (-4.5C) and 7.2C (-4.7C).

Sunday started with limited brightness but predominantly cloudy after low cloud and mist lifted from the local hills.

The barometric pressure has begun to lift as an anticyclone in mi-Atlantic begins to build. The temperature at 08.00 was 11.9C, the coolest morning at that time for a week, and pressure of 1019.3mb.

Below average temperatures for start of month

The thermometer only reached a maximum of 21.3C on Friday, which was 1.4C bleep the early July average and overnight also a below minimum of 10.C (-1.1C). However, the day was dry and the UV rose to Very High again. The breeze from the southwest was moderate in strength, gusting to 17mph.

Saturday early in the day brought short bursts of sunshine but thick cloud from an advancing rain-band began to obscure the sun just before 08.00 by which time the temperature had risen to 14.0C.

June 2022 Review

The month began with a cool north-easterly for three days, temperatures were depressed by day. Modest rain showers fell on three days, the wettest brought 8.7mm on the 5th, the highest daily rainfall in three weeks.

Ex-tropical Storm Alexa brought a glancing blow to our area, passing well to the north, but produced windy days from the 8th to the 10th with a peak gust of 24mph on the 8th.

By the 11th an Azores high began to influence our weather with many hours of sunshine and temperatures by day above average.

The media made much of a possible heatwave starting on the 14th. In fact the thermometer did rise very high but not quite sufficient to be classed as a heatwave for this area. At the end of this review is an article from the Meteorological Office of June 2022 on heatwaves and some research I have done using the Marlborough data from recent years showing very interesting results.

The plume of hot air arrived on the 15th and built over the next three days peaking at 31.3C on the 17th making it the hottest day since June 2020 but just below the record of 32.2C on 21st June 2017.

It was all change on the 18th as a cold front arrived and an associated change in wind direction from south to north. The change brought much colder air that meant the thermometer hovered around 13C most of that day, almost 20C below the previous day’s peak.

As the colder air bumped against the hot, moist air from the south heavy rain showers built with 6.8mm during the late evening of the 17th. Much more heavy and prolonged rain fell to the northwest of this area so my garden didn’t receive as much as I would have liked.

Another hot spell arrived on the 21st with a peak of 26.9C on the 22nd as winds from the northeast were light with high solar energy and the UV level peaking at Very High around midday.

The last week saw minimal rainfall as a blocking high pressure system to the east of the UK kept the majority of the rain bands to the west of Marlborough or weakened any showers that got through. On numerous previous occasions I have watched the 5-minute rainfall radar display and seen as the rain showers approached the cloud thinned or often diverted to the west or east of this area. There were three days when heavy downpours were reported in the south of the country but we received just 1.0mm, 1.3mm and 1.6mm on the 27th, 28th and 30th respectively.

The rainfall for June totalled 27.2mm, just 50% of the 38-year average or minus 27mm. The trend of drier months this year has continued since January as only February was above average. The wettest June was in 1998 when 143.2mm was recorded and the driest occurred in 2018 with just 5.3mm. The wettest day this month occurred on the 5th with 8.7mm.

Not only was June relatively dry but also the loss of equivalent rainfall through evaporation from ground sources and plant life was 95.3mm. Therefore there was a total loss of 68.1mm of equivalent rainfall.

Another record has been established for this station. The total rainfall for the six-month period from January to June was 246.9mm. This made it the driest since my records began in 1984 being 140.7mm below the average.

The mean temperature for June was 0.3C above the 38-year average. In fact the trend for warmer Junes can be seen in a rising trend since 1996.

What is a heatwave?
A heatwave is an extended period of hot weather relative to the expected conditions of the area at that time of year, which may be accompanied by high humidity.
What is the definition for a UK heatwave?

A UK heatwave threshold is met when a location records a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold. The threshold varies by UK county in the UK.

The Met Office heatwave threshold has been updated ahead of summer 2022. The initial heatwave thresholds were calculated based on the 1981-2010 climatology of daily maximum temperature at the mid-point of the meteorological summer (15 July). The revised thresholds will use the 1991-2020 average period introduced in January 2022. The geographical differences reflect the differences in climate across the UK.

Why do heatwaves happen?
Heatwaves are most common in summer when high pressure develops across an area. High pressure systems are slow moving and can persist over an area for a prolonged period of time, such as days or weeks. They can occur in the UK due to the location of the jet stream, which is usually to the north of the UK in the summer. This can allow high pressure to develop over the UK resulting in persistent dry and settled weather.

Are heatwaves linked to climate change?
Summer 2018 was the equal-second warmest summer in a UK series from 1884 for mean daily maximum temperature (shared with 1995) with summer 1976 hottest.

Heatwaves are extreme weather events, but research shows that climate change is making these events more likely. A scientific study by the Met Office into the Summer 2018 heatwave in the UK showed that the likelihood of the UK experiencing a summer as hot or hotter than 2018 is a little over 1 in 10. It is 30 times more likely to occur now than before the industrial revolution because of the higher concentration of carbon dioxide (a greenhouse gas) in the atmosphere. As greenhouse gas concentrations increase heatwaves of similar intensity are projected to become even more frequent, perhaps occurring as regularly as every other year by the 2050s. The Earth’s surface temperature has risen by 1 °C since the pre-industrial period (1850-1900) and UK temperatures have risen by a similar amount.

Heatwave impacts
The UK experiences occasional heatwaves but of a lesser frequency and intensity of those seen elsewhere globally. The summer of 2018 was the equal-warmest summer for mean temperatures in the UK along with 2006, 2003 and 1976. The hottest day of the summer was on 27 July, with 35.6 °C recorded at Felsham, Suffolk.

The weather and climate body said the three-day temperature threshold for a heatwave would increase from 27C to 28C for six counties: Surrey, Berkshire, Buckinghamshire, Bedfordshire, Hertfordshire, Cambridgeshire.

“As greenhouse gas concentrations increase, heatwaves of similar intensity are projected to become even more frequent, perhaps occurring as regularly as every other year.”

I analysed my data for the past twelve years going back to 2010 to see if any patterns emerged. The heatwave threshold for Marlborough was lifted to 27C in the 1981-2010 and the more recent 1991-2020 data set. The two graphs illustrate quiet clearly that changes are evident. Do remember that a heatwave happens when a location records at least three days in a row with daily maximum temperatures meeting or exceeding a certain threshold.
The data illustrates that the number of days during which a heatwave occurs show a rising trend. The limited data period indicates that the number of days has risen from three to five or six. In addition the average temperature in a heat wave also shows a rising trend with +1C over the last 20 years.

Fifth below average rainfall month this year

A minimal 1.6mm of rain fell on Thursday as showers were frequent but not this area. The rainfall total for June stands at 27.2mm being just 50% of the 38-year average of 27mm below.

The thermometer rose to 18.9C being 1.3C below average.

The minimum overnight temperature was 10.4C, just above average.

June 2022 Review

The month began with a cool north-easterly for three days, temperatures were depressed by day. Modest rain showers fell on three days, the wettest brought 8.7mm on the 5th, the highest daily rainfall in three weeks.

E-tropical Storm Alexa brought a glancing blow to our area, passing well to the north, but produced windy days from the 8th to the 10th with a peak gust of 24mph on the 8th.

By the 11th an Azores high began to influence our weather with many hours of sunshine and temperatures by day above average.

The media made much of a possible heatwave starting on the 14th. In fact the thermometer did rise very high but not quite sufficient to be classed as a heatwave for this area. At the end of this review is an article from the Meteorological Office of June 2022 on heatwaves and some research I have done using the Marlborough data from recent years showing very interesting results.

The plume of hot air arrived on the 15th and built over the next three days peaking at 31.3C on the 17th making it the hottest day since June 2020 but just below the record of 32.2C on 21st June 2017.

It was all change on the 18th as a cold front arrived and an associated change in wind direction from south to north. The change brought much colder air that meant the thermometer hovered around 13C most of that day, almost 20C below the previous day’s peak.

As the colder air bumped against the hot, moist air from the south heavy rain showers built with 6.8mm during the late evening of the 17th. Much more heavy and prolonged rain fell to the northwest of this area so my garden didn’t receive as much as I would have liked.

Another hot spell arrived on the 21st with a peak of 26.9C on the 22nd as winds from the northeast were light with high solar energy and the UV level peaking at Very High around midday.

The last week saw minimal rainfall as a blocking high to the east of the UK kept the majority of the rain bands to the west of Marlborough or weakened any showers that got through. On numerous previous occasions I have watched the 5-minute rainfall radar display and seen as the rain showers approached the cloud thinned or often diverted to the west or east of this area. There were three days when heavy downpours were reported in the south of the country but we received just 1.0mm, 1.3mm and 1.6mm on the 27th, 28th and 30th respectively.

The rainfall for June totalled 27.2mm, just 50% of the 38-year average or minus 27mm. The trend of drier months this year has continued since January as only February was above average. The wettest June was in 1998 when 143.2mm was recorded and the driest occurred in 2018 with just 5.3mm. The wettest day occurred on the 5th with 8.7mm.

Not only was June relatively dry but also the loss of equivalent rainfall through evaporation from ground sources and plant life was 95.3mm. Therefore there was a total loss of 68.1mm of equivalent rainfall.

Another record has been established for this station. The total rainfall for the six-month period from January to June was 246.9mm. This made it the driest since my records began in 1984 being 140.7mm below the average.

The mean temperature for June was 0.3C above the 38-year average. In fact the trend for warmer Junes can be seen in a rising trend since 1996.

What is a heatwave?
A heatwave is an extended period of hot weather relative to the expected conditions of the area at that time of year, which may be accompanied by high humidity.

What is the definition for a UK heatwave?
A UK heatwave threshold is met when a location records a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold. The threshold varies by UK county in the UK.

The Met Office heatwave threshold has been updated ahead of summer 2022. The initial heatwave thresholds were calculated based on the 1981-2010 climatology of daily maximum temperature at the mid-point of the meteorological summer (15 July). The revised thresholds will use the 1991-2020 average period introduced in January 2022. The geographical differences reflect the differences in climate across the UK.

Why do heatwaves happen?
Heatwaves are most common in summer when high pressure develops across an area. High pressure systems are slow moving and can persist over an area for a prolonged period of time, such as days or weeks. They can occur in the UK due to the location of the jet stream, which is usually to the north of the UK in the summer. This can allow high pressure to develop over the UK resulting in persistent dry and settled weather.

Are heatwaves linked to climate change?
Summer 2018 was the equal-second warmest summer in a UK series from 1884 for mean daily maximum temperature (shared with 1995) with summer 1976 hottest.
Heatwaves are extreme weather events, but research shows that climate change is making these events more likely. A scientific study by the Met Office into the Summer 2018 heatwave in the UK showed that the likelihood of the UK experiencing a summer as hot or hotter than 2018 is a little over 1 in 10. It is 30 times more likely to occur now than before the industrial revolution because of the higher concentration of carbon dioxide (a greenhouse gas) in the atmosphere. As greenhouse gas concentrations increase heatwaves of similar intensity are projected to become even more frequent, perhaps occurring as regularly as every other year by the 2050s. The Earth’s surface temperature has risen by 1 °C since the pre-industrial period (1850-1900) and UK temperatures have risen by a similar amount.

Heatwave impacts
The UK experiences occasional heatwaves but of a lesser frequency and intensity of those seen elsewhere globally. The summer of 2018 was the equal-warmest summer for mean temperatures in the UK along with 2006, 2003 and 1976. The hottest day of the summer was on 27 July, with 35.6 °C recorded at Felsham, Suffolk.

The weather and climate body said the three-day temperature threshold for a heatwave would increase from 27C to 28C for six counties: Surrey, Berkshire, Buckinghamshire, Bedfordshire, Hertfordshire, Cambridgeshire.

“As greenhouse gas concentrations increase, heatwaves of similar intensity are projected to become even more frequent, perhaps occurring as regularly as every other year.”

I analysed my data for the past twelve years going back to 2010 to see if any patterns emerged. The heatwave threshold for Marlborough was lifted to 27C in the 1981-2010 and the more recent 1991-2020 data set. The two graphs illustrate quiet clearly that changes are evident. Do remember that a heatwave happens when a location records at least three days in a row with daily maximum temperatures meeting or exceeding a certain threshold.
The data illustrates that the number of days during which a heatwave occurs show a rising trend. The limited data period indicates that the number of days has risen from three to five or six. In addition the average temperature in a heat wave also shows a rising trend with +1C over the last 20 years.

Blocking high keeps away rain

The high pressure to the east as meant rain bands coming in from the west have been blocked or severely weakened before they reach our area, thus minimal rain in the last week and no rain at all on Wednesday.

The rainfall for June stands at 25.6mm being just 47% of the 38 year average. Loss of equivalent rainfall through evaporation now stands at 93mm for June.

The thermometer rose to 21.8C been 1.6C above the average and fell away to 10.6C, just above average overnight.

Thursday began with broken cloud and intervals of strong sunshine that lifted the temperature to 14.4C at 08.00.

Due to the lack of rain, hours of strong sunshine and strong drying winds, the ground is quite dry and warm. The temperature at a depth of 5cm read 17.8C at 08.00.

Minimal rain – again!

Tuesday brought an average maximum temperature of 20.1C in the blustery southwesterly wind, gusting to 27mph.

The day was dry but a light shower arrived just after 01.00 on Wednesday amounting to just 1.3mm. The rainfall total for June now stands at only 25.6mm, just 47% of the 38-year average, which is 54.2mm with only two days of the month left. It is looking as if this will be the fifth below average month in 2022 as only February was above average. The gardens are very dry, last night just washed off the dust from plants but had evaporated in the early morning sunshine and dry air. Some of the plants in my garden on Tuesday were showing signs of stress in the strong, dry wind.

It has been a very mild night with the thermometer not sinking below 12.3C being 2.2C above the average

Wednesday brought blue sky and glorious sunshine – until 06.40, when cloud began to drift across from the south and obscured most of the sunshine.