Monthly Summary - August 2011

   August was once again an uninspiring month that epitomized a totally underwhelming Summer - it was very much a cyclonic month with high pressure notable by its absence and hence it was unsettled, cooler and wetter than average. There were no spells of any warmth with many days experiencing rain and it was also cloudy and dull with sunshine very much at a premium.

   The month started poorly and indeed rain was recorded on all of the first 16 days, the first week especially seeing some significant falls.

   The 1st and 2nd were cloudy and murky, the 1st was showery whilst a more organised band of rain passed through on the 2nd and brougth 8.0mm of rain. An 'Area of Low Pressure' (ALP) (993 Mb) was NW of the UK and had an occluded front lying N to S across Western parts of the UK with a waving front behind that brought the more organised rain on the 2nd. However, the 2nd was one of only two days in the month to attain 20°c and hence it felt a little muggy.

   The 3rd saw us sit inbetween weather systems and this brought the months warmest and possibly best day. It was still only a day of sunny intervals but reached 21.9°c (71.4°F), but a complex ALP (998) was out in the Atlantic and moving our way and was to control our weather for a number of days. Heavy rain from 0730 hrs on the 4th was the result as a frontal system SW of the UK and carrying warm and moist air moved NE. It resulted in 15.3mm of rain and was all quite unpleasant, although the rain did finally clear later in the day.

   The 5th had a fresher feel behind the weather fronts from the previous day, but the 6th was to be a terrible day.

   The 6th saw a complex ALP (1003) covering the UK with a steeply falling pressure gradient and various rain bearing troughs moving through. However, the winds were very light and those bands of rain were slow moving and heavy at times making the 6th the months wettest day with 16.6mm (a total of 19.5mm actually fell but 2.9mm was credited to the 5th due to the recording hours of 1000x1000). Throw in a few rumbles of thunder at lunchtime and a chillingly cold temperature of just 13.7°c and the day was more akin to mid Autumn than Summer. Unfortunately more Autumnal days were still to come!

   The rain on the 6th also saw the yearly total go over the total amount of 702.9mm recorded in 2010.

   Things now became a little cooler with day-time temps' typically 17-18°c and the days had a mix of cloud, showers and a few sunnier spells. Low pressure was still resident over or near the UK but the wind had veered WNW'ly then NW'ly due to ALP (994) east of the UK and an 'Area of High Pressure' (AHP) to our West, but the 10th saw yet more organised rain as an ALP stormed our way.

   The 10th with 6.1mm of rain and the 11th with 12.1mm were wet as a slow moving ALP North of the UK with its weather fronts moved through, with the 11th seeing several ALP strung out from the Baltic to mid Atlantic and for us an active front brought the moist air resulting in that rain.

   After a few cloudy days with some heavy showers that saw less humid air drawn down from the North Atlantic, it was still low pressure that was influencing our weather. The 15-16th saw another 9.0 mm of rain and then the 17th was the first totally dry day of the month and whilst it felt fresh we had some sunny spells.

   We were now sat in a slack area with an ALP to the north of the UK and that gave light W'ly winds and both the 17th and 19th saw the lowest temperatures of the month at 4.8°c (40.6°F) with a ground temperature of just 1.3°c on the 17th.

   The 19th saw the rarity of a ridge of high pressure extending North from the Azores and provided a reasonable day and at least the rain (3.8mm) did the decent thing and arrived late in the evening. That rain continued into the 20th but had cleared by morning and the day started well with watery sun becoming more pronounced as the cloud broke up, but an occlusion front arrived mid afternoon and with it yet more rain (8.1 mm.)

   We then actually had a run of three consecutive dry days, 21-23rd, as a ridge of high pressure extended from northern Europe, but the final week of the month was to see more rain, although nothing as significant as at the start of the month, but now the temperatures were going to fall away quite noticeably.

   The 24th saw a reasonable start but with showers passing through during the afternoon caused by a trough connected to an ALP (998) West of Eire. After a pleasant enough day on the 25th (that made two for the month then!) with a temperature of 18.2°c, the chill set in and just in time for the Bank holiday weekend!

   The UK was surrounded by active weather systems and the main one was located in Northern France. This would push North into the UK and whilst it brought terrible conditions for the South and East of the UK, its journey only had minimal impact on us with some light rain and showers on 26-27th.

   This ALP pushed NE of the UK and with a weak AHP North of the Azores this allowed for a W-NW'ly air flow of Polar Maritime origins. This tends to be 'cleaner' air and in summer rain will tend to be in the form of showers, but it will be cool. The last four days of the month all failed to attain 15°c and whilst we did have days of sunny intervals it was fresh and the breeze was also quite noticeable.

   The month ended with high pressure to our South which still gave us a W'ly flow over its top edge and hence cloudy and cool conditions. The 30th at 13.4°c (56.1°F) was the months coldest day (and coldest August maximum temperature recorded at this site) and that temperature virtually remained unchanged all day - and then it also rained in the afternoon.

   So the month was the coldest August recorded at this site, although just 0.1°c colder than last year and six days recorded day-time max' temperatures below 15°c, the three previous Augusts had a combined total of just five!

   Rainfall totalled 108.7 mm for the month, with rain recorded on 23 days of which 17 were 'Wet days' (1.0mm +).

   The Mean Temperature for the month was 13.38°c+         --      The Mean Max' was   17.53°c   --    The Mean Min'   9.24°c.

   We had 0 Air Frosts in the month (year 30)      --      Grass frosts totalled 0 (year 50).

   The 30 cm soil temp ranged from 14.0°c on the 30-31st      to      17.2°c on the 1-2nd and 4th      --      with a monthly mean of 15.7°c


   * August 2011 rainfall was 117.8% of the August average for 2007 - 2010

   * August 2011 was 0.14°c colder than August 2010 +

  * The 3 month mean for June/July/August 2011 is                   TEMP'    13.17°c         --          RAIN    244.1 mm

* June/July/August 2010 was TEMP'    13.97°c -- RAIN    199.8 mm

* June/July/August 2009 was TEMP'    14.34°c -- RAIN    349.6 mm

* June/July/August 2008 was TEMP'    -- RAIN    325.2 mm

* June/July/August 2007 was TEMP'    -- RAIN    355.7 mm


* 2011 To date TEMP'    9.20°c -- RAIN    777.6 mm

* 2010 Jan - Aug TEMP'    8.26°c -- RAIN    373.2 mm

* 2009 Jan - Aug TEMP'    9.44°c -- RAIN    760.3 mm

* 2008 Jan - Aug TEMP'   -- RAIN    861.7 mm

 + Met office figures for August show that NW England/N. Wales had a mean temp' of 14.1°c, this being -0.6°c colder than the reference period 1971-2000 (-0.2°c colder than reference period 1961-90)


JANUARY 2010    FEBRUARY 2010    MARCH 2010    APRIL 2010    MAY 2010    JUNE 2010    JULY 2010    AUGUST 2010    SEPTEMBER 2010    OCTOBER 2010    NOVEMBER 2010    DECEMBER 2010   

JANUARY 2011    FEBRUARY 2011    MARCH 2011    APRIL 2011    MAY 2011    JUNE 2011    JULY 2011   

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