Monthly Summary - April 2012

   After the warmth of March, April went the other way and was both wet and cool and indeed April was far colder than March. March had seen a mean temperature of 7.7°c whilst April could only manage 6.18°c. Such an event is not that uncommon when you consider that using the Central England Temperature series (CET), since 1659 April has been colder than March on 13 occasions in 352 years, an average recurrence of 27 years. Notably, nine of the 13 occurred in the 20th century, most recently in 1998 (-0.2 degC). Also there were no such occurrences in almost 100 years between 1809 and 1903.

   It was the fourth wettest April in the England & Wales series which began in 1727. Rainfall totalled 91.9 mm (3.62 in.) and locally (in a sporadic series) I find that Crosby Ravensworth was wetter in 1947 with 238 mm (9.37 inch) with 1974 being the driest with just 0.4 mm (0.2 mm). During 1902-44 in Morland, April was, on average, the driest month of the year with only 1913 and 1935 recording more.

   Low pressure (LP) was dominant for the vast majority of the month, apart from the 1st, the 5-7th and the 28th. Those LP systems tended to get stuck over or near the UK and brought frequent showers and cool days with winds from a north to an easterly quarter prevalent. At least the main spells of heavy rain during the month (10th, 12th, 17th and 26th) came during the night.

   The month started with the 1st being the 15th successive day without any measurable rainfall, this been the minimum period to be termed 'Absolute Drought', but that drought lasted no further. The High Pressure (HP) (1027 Mb) that had brought the fine weather in March was in the mid Atlantic and made April Fool's day the best day of the month as it was sunny throughout with barely a cloud. At 12.5°c it was only surpassed as the month's warmest day on the 30th.

   The 3rd saw LP centred over north east Scotland with a cold front to our west and as this moved south it brought a period of wintry showers that became a more organised spell of snow during the afternoon. And it was cold with a brisk NE'ly wind drawn down for both the 3rd and 4th, gusting to 49 Mph on the 4th. As a consequence the 4th was the month's coldest day at just 6.8°c (44.2°F), but at least the day was one of sunny intervals.

   The 5th was a beautiful but cold day with wall to wall sun as an area of high pressure (HP) extended a ridge over the north of the UK. A frost of -4.3°c (24.3°F) and ground frost of    -8.6°c made the 5th the month's coldest day, but that HP gave way during the 6th allowing a cold front to push south out of Scotland that brought a little rain. HP briefly returned on the 7th and brought a settled but cloudy day.

   The Easter weekend (6-9th) was generally a cool and cloudy affair with spells of light rain as a slow moving cold front moved south out of Scotland, with the Bank Holiday Monday (9th) especially cool at 7.7°c.

   LP returning from the 8th and bringing showery conditions through to the 13th. Firstly the 9th saw light rain in the afternoon become increasingly heavy late evening and overnight into the 10th. This gave 12.0 mm of rain as a SW'ly flow became established due to LP near Iceland which pushed cold fronts eastwards.

   More heavy rain, 13.9 mm, fell in the early hours of the 12th as the LP (now between Scotland and Norway) was still dominating and which had numerous troughs lines circulating around the depression in an unstable NW'ly flow.

   Whilst LP was still nearby for the 14-16th we were sat within a slack area in that LP and this gave calmer conditions in a lighter flow and hence overnight frosts. The clouds generally cleared overnight to allow those frosts, typically -1.4°c, but the cloud would soon build during the morning. The 16th saw a deep depression approaching from the Atlantic and this brought heavy rain (11.9 mm) in the early hours of the 17th and a then a day of showers and sunny intervals but with a cool wind.

   Temperature during the period of the 14-18th remained low at just under 9.0°c and the 18th was a cool and dull day that saw rain move in during the afternoon and stay for the rest of the day. LP was moving north from the south of the UK and brought this rain and for the period upto the 24th that LP either sat in the North Sea or over the UK. Various trough lines circulated around this LP and this resulted in showery conditions, although Cumbria tended to miss the worst of these conditions as for the 21st - 24th we once again sat in a fairly slack area of that LP.

   However, for the 22nd to the month's end the flow was generally NE to easterly and that wind felt cold and again the temperatures remained pegged back below 10°c. A new area of LP (976) pushed into the SW of the UK for the 25-27th and brought a cool easterly circulating around its top edge. Rain arrived in the afternoon and then very heavy rain overnight into the 26th as various troughs and frontal systems connected to that LP (979 and now over Wales) tracked NE. Using 09-0900 hrs readings this made the 25th the month's wettest day with 16.0 mm with a further 8.8 mm credited to the 26th as that rain, heavy at times, made the 26th a thoroughly miserable day.

   The 28th saw a weak ridge of HP give a slight frost overnight, but with that LP to our south it still brought a chill NE'ly, but at least the day was dry and bright.

   The 29th was possibly the month's poorest day and certainly if the standard recording hours were Mid-night to Mid-night then it would also have been the coldest day of the month as the temperatures barely ventured as high as 6.0°c. LP over France spilled north and the occluded front ahead of it brought an afternoon and evening of rain (6.5 mm) and a cold gusty NE'ly wind.

   Once that rain had cleared the temperature started to lift during the early hours of the 30th and by the morning were above 10.0°c (as standard recording hours are 09-0900 Hrs this saw 10.9°c credited to the 29th and thus why it was not the month's coldest day!). The 30th was then a reasonable day and at 15.1°c (59.2°c) was by far the month's warmest day. But in my time recording at this site, this is the lowest day-time maximum temperature recorded for April.

   So overall a disappointing month and one that save for the odd decent day offered little. Even my first sighting of a Swallow (22nd) was just over a week later than normal.

 

   Rainfall totalled 91.9 mm for the month, with rain recorded on 19 days of which 14 were 'Wet days' (1.0mm +).

   The Mean Temperature for the month was 6.18°c+         --      The Mean Max' was   10.01°c   --    The Mean Min'   2.34°c.

   We had 6 Air Frosts in the month (year 34)      --      Grass frosts totalled 17 (year 75).

   The 30 cm soil temp ranged from a high of 9.5°c on the 23rd      to      a low of 7.6°c on the 5th      --      with a monthly mean of 8.8°c

   The 1 meter soil temp ranged from a high of 8.8°c on the 16th      to      a low of 8.0°c on the 8th      --      with a monthly mean of 8.4°c

 

COMPARISONS:-

   * April 2012 rainfall was 226.2% of the April average for 2008 - 2011

   * April 2012 was 4.06°c colder than April 2011      --      1.69°c colder than April 2010      --      2.61°c colder than 2009



  * The 3 month mean for February/March/April 2012 is                   TEMP'    5.83°c         --          RAIN    160.9 mm

* February/March/April 2011 was TEMP'    6.91°c -- RAIN    278.3 mm

* February/March/April 2010 was TEMP'    4.68°c -- RAIN    122.0 mm

* February/March/April 2009 was TEMP'    6.01°c -- RAIN    113.3 mm

* February/March/April 2008 was TEMP'    -- RAIN    285.1 mm

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* 2012 To date TEMP'    5.32°c -- RAIN    251.6 mm

* 2011 Jan - April TEMP'    5.80°c -- RAIN    420.9 mm

* 2010 Jan - April TEMP'    3.60°c -- RAIN    158.6 mm

* 2009 Jan - April TEMP'    5.38°c -- RAIN    339.5 mm

* 2008 Jan - April TEMP'    -- RAIN    511.3 mm

 + Met office figures for April -- NW England/N. Wales had a mean temp' of 6.4°c, this being -0.7°c colder than the reference period 1971-2000 (-0.4°c colder than reference period 1961-90)

   PREVIOUS MONTHS REPORTS

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    AUGUST 2011    SEPTEMBER 2011    OCTOBER 2011    NOVEMBER 2011    DECEMBER 2011   

JANUARY 2012   FEBRUARY 2012   MARCH 2012  

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