Windrush Weather

Category: Commentary

  • The sun returns

    The influence of the high pressure in mid-Atlantic was evident yesterday as the strong sunshine of 3.13 hours was the highest for four days. This pushed the thermometer to a maximum of 21.6C, just below average.

    The clear skies at times raised the UV level to 9.5, which is Very High. No rain fell.

    Just before 4am the barometer started to rise, the wind veered from a westerly direction into the north.

    This morning the thermometer has recovered from a minimum of 14.1C to 15.8C at 08.00 as intermittent sunshine has broken through the broken cloud.

    June Summary

    June was a memorable month for a number of meteorological reasons; not least the breaking of temperature records at this station that was started in 1984.

    On the 19th the mini heat wave boosted the thermometer to a thirty-three year record for this station with a maximum of 31.4C. Just two days later, at the peak of the hot weather, the temperature soared again to a maximum of 32.2C. This was 12.5C above the long-term daily average.

    The average minimum temperature was 11.74C being 2C above the long-term average with a similar value of +1.9C for the daytime average.

    Although the warmth gradually dissipated after this time it was a record breaking month with the mean temperature 1.95C above the long-term average breaking the previous record set in 2006 by 0.1C.

    Living at these latitudes and in our unique position geographically, being close to the continental land mass and large areas of water, we are used to wide fluctuations in the day to day and day to night temperatures. On the 18th there was a variation of 19.7C between day and night time extremes yet ten days later, on the 28th, the variation was just 2C.

    Turning to the rainfall, it was another below average month, the fifth this year. The total was 35.0mm, being 64% of the long-term average or a monthly deficit of 20mm. The last six months have produced a deficit of 79mm (or over three inches) compared to the long-term average.

    We have also experienced five consecutive years of below average June rainfall totals following the extreme amount of 127.9mm in 2012. The record of 143.2mm was set in 1998 and by contrast in 1995, a very dry month with just 12.5mm.

    It is important to remember that much moisture from ground sources and plant life evaporated during each day with in excess of 5mm of equivalent rainfall on two days. The total evaporation for the month was 96.8mm; almost three times the total rainfall for June.

    Strong sunshine amounted to 128 hours being 10 hours below the average for the last three years when this instrument was installed.

    Solar energy was just above the seven-year average with a figure of 102%.

    The UV levels have varied throughout the month from 2.9 (low) during the miserable day on the 28th to 10.4 (Extreme) that occurred briefly on the 24th. This latter level has only been recorded once before, in June 2011, since this instrument was installed in the autumn of 2009.

    Not surprisingly, the average soil temperature (17.7C) at a depth of 5cm was 2.4C above the average for this thermometer that was installed in 2014.

    I think the quotation from Gertrude Jekyll, the influential British horticulturist, garden designer, artist and writer who created over 400 gardens in the United Kingdom, is appropriate to describe the past month. “What is one to say about June, the time of perfect young summer, the fulfilment of the promise of the earlier months and with as yet no sign to remind one that its fresh young beauty will ever fade.”

  • Summary for June 2017

    June was a memorable month for a number of meteorological reasons; not least the breaking of temperature records at this station that was started in 1984.

    On the 19th the mini heat wave boosted the thermometer to a thirty-three year record for this station with a maximum of 31.4C. Just two days later, at the peak of the hot weather, the temperature soared again to a maximum of 32.2C. This was 12.5C above the long-term daily average.

    The average minimum temperature was 11.74C being 2C above the long-term average with a similar value of +1.9C for the daytime average.

    Although the warmth gradually dissipated after this time it was a record breaking month with the mean temperature 1.95C above the long-term average breaking the previous record set in 2006 by 0.1C.

    Scientists say these extremes are made more likely because of climate change.

    Living at these latitudes and in our unique position geographically, being close to the continental land mass and large areas of water, we are used to wide fluctuations in the day to day and day to night temperatures. On the 18th there was a variation of 19.7C between day and night time extremes yet ten days later, on the 28th, the variation was just 2C.

    Turning to the rainfall, it was another below average month, the fifth this year. The total was 35.0mm, being 64% of the long-term average or a monthly deficit of 20mm. The last six months have produced a deficit of 79mm (or over three inches) compared to the long-term average.

    We have also experienced five consecutive years of below average June rainfall totals following the extreme amount of 127.9mm in 2012. The record of 143.2mm was set in 1998 and by contrast in 1995, a very dry month with just 12.5mm.

    It is important to remember that much moisture from ground sources and plant life evaporated during each day with in excess of 5mm of equivalent rainfall on two days. The total evaporation for the month was 96.8mm; almost three times the total rainfall for June.

    Strong sunshine amounted to 128 hours being 10 hours below the average for the last three years when this instrument was installed.

    Solar energy was just above the seven-year average with a figure of 102%.

    The UV levels have varied throughout the month from 2.9 (low) during the miserable day on the 28th to 10.4 (Extreme) that occurred briefly on the 24th. This latter level has only been recorded once before, in June 2011, since this instrument was installed in the autumn of 2009.

    Not surprisingly, the average soil temperature (17.7C) at a depth of 5cm was 2.4C above the average for this thermometer that was installed in 2014.

    I think the quotation from Gertrude Jekyll, the influential British horticulturist, garden designer, artist and writer who created over 400 gardens in the United Kingdom, is appropriate to describe the past month. “What is one to say about June, the time of perfect young summer, the fulfilment of the promise of the earlier months and with as yet no sign to remind one that its fresh young beauty will ever fade.”

  • Two sunless days and maxima 4C below average – NOT summer!

    Yesterday was a day to put back on a jumper as the thermometer struggled to reach 15.8C late in the day, at 17.08, which was 4C below the June average. The mitigating factor was the low wind speed with the maximum gust all day of just 10mph. No sunshine was recorded, the second consecutive sunless day and the last time this occurred was in mid-May.

    The UV level did rise from the abysmal ‘Low’ level of the previous day, just making it into the ‘High’ category for a brief instant at lunchtime.

    With no rain again the total for June stands at 34.4mm, which is 21mmm short of the average for June.

    The cloud cover meant anther mild night wth a minimum of 12.0C, some 2.3C above the average for June

    The first effects of the high pressure off to the west of the country are seen this morning as the barometric pressure has been rising resulting in very welcome intermittent sunshine a couple of hours after dawn.

    With data for the last day of the month still to be recorded, it looks as if it will have been a very warm month with the average approaching 2C above average.

  • No sun, no rain, little solar energy – dismal

    What a dismal day yesterday was.

    It was the lowest UV level (2.9), the lowest evaporation (0.72mm) and lowest solar energy since 17th May. Not summer!

    As a consequence of the thick cloud and modest breeze from the north east the maximum was only 15.6C, which was 4C blew the average for June and 17C below the peak exactly a week ago.

    Overnight the thermometer fell to 10.5C, just above average for June.

    This morning is grey with thick cloud and very little wind.

    Over the past thirty three years I have frequently observed that summer storms move northwards to the west or east of us. Not far to the east of Marlborough, west Hampshire, received in excess of 60mm of rainfall in the recent storms with Westonbirt Arboretum receiving 36mm. From experience driving down and back from Cornwall, yesterday, there were copious amounts of rainfall to the west of us, from the same weather system. This does not apply to weather fronts that move in from the Atlantic.

    With two days to go before the end of the month there is currently a deficit in the rainfall total, compared to the average, of 21mm.

  • Second wettest day this month BUT only 3.3mm

    A virtually sunless day yesterday but still above average maximum of 20.7C (+1C). In the early evening the first spots of rain fell with heavier showers late evening. The total rainfall was 3.3mm, making it the second wettest day this month but still only brings the total for June to 62% of the 33-year average.

    Gardeners and farmers will be disappointed at this little rainfall as it only dampens the top 1cm of soil.

    This morning has dawned with very low cloud giving misty conditions and visibility down to 800 metres. Humidity at 08.00 was 98%, the highest this month. It was a mild night with the thermometer only dropping to 13.9C (+4C) and light winds.