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graphs CLIMATE-UK.COM'S REVIEW OF THE BRITISH METEOROLOGICAL SCENE
MONTHLY SUMMARY
No. 676 For APRIL 2012
OVER ENGLAND AND WALES THE COLDEST SINCE 1989, THE DULLEST SINCE 1998, AND THE WETTEST SINCE 2000
Text Box: Atlantic fronts swept across the country on the 17th, and the parent depression subsequently drifted over England and Wales; indeed low pressure persisted over the UK until the 27th. There were periods of prolonged heavy rain on both the 17th/18th, 56mm in 48h at Fylingdales (North Yorks), and the 25th/26th, 62mm in 48h at Tideswell (Derbys), and between these major rainfall events the weather reverted to a showery type, once again with widespread heavy showers, often bringing hail and thunder as well, but with occasional sunny breaks. 

From late on the 27th pressure became high over Scotland, with a northeasterly flow across England and Wales. The next two days were very sunny in many parts of Scotland with 15.1h bright sunshine at Dunstaffnage (Argyll) on the 29th, but England and Wales again became very wet with 75mm in 48h at Liscombe (Somerset). The northeasterly wind also became strong with gusts to 66kn at Warcop (Cumbria) and 62kn at Mumbles (Glamorgan). The 30th was drier, brighter and warmer over central and eastern England, with 19.7C reached at Kew Gardens (London).

Mean temperatures were typically 1.0-1.5 degC below the 1981-2010 average, though the deficit was less than 1.0 degC in East Anglia and Southeast England. As measured by the CET it was the coldest April since 1989, though seven were colder in the 25 years 1965-89. Rainfall over England and Wales was 140.4mm, second only to April 2000 in the series which began in 1766. More than twice the normal amount fell over much of eastern Scotland and most of England except the northwest, while 3 to 3.5 times fell in a zone stretching from York to Peterborough.  Monthly totals ranged from 290mm at Liscombe (Somerset) to 31mm at Auchincruive (Ayrshire). Sunshine exceeded the long-term average in Northern Ireland, parts of western Scotland and the Channel Islands, but amounted to less than half the normal locally in eastern Scotland. Monthly totals ranged from 71 hours at Dyce (Aberdeenshire) to 237 hours at Tiree (Argyll).
Text Box: This was the fifth most cyclonic and also the fifth most northerly April since 1873, resulting in a cold and very wet month. Pressure was briefly higher on the 1st, 5th/6th and 15th/16th, otherwise low pressure was consistently in charge; on both the 18th and 25th pressure fell to 973 mbar at Milford Haven and Scilly respectively, the lowest in April for eight years.

High pressure lay west of Ireland on the 1st which was a largely dry and quite sunny day from central Scotland southwards, although rain fell in northern Scotland. A vigorous depression formed on a cold front over Scotland on the 2nd and travelled slowly southwards during the next couple of days. Rain fell widely, and turned readily to snow, chiefly but not exclusively over high ground, as a strong northeasterly wind kicked in. Some 15-25cm snow lay over the Scottish highlands, the Pennines, the Peak District and the north Welsh hills for a time, and it was arguably the severest and most widespread April snowstorm since 1981. At Cranwell (Lincs) 50mm of rain fell over a 48h period, while the maximum temperature was 0.3C at Carter Bar (Roxburghshire) on the 3rd and also at Pennerley (Salop) on the 4th. Under clear skies associated with a southward-moving ridge, the temperature dropped to -8.2C at Braemar (Aberdeenshire) early on the 5th, and to -7.1C at Chesham (Bucks) on the 6th.

The Easter weekend (6th-9th) was generally cloudy and rather cold with occasional rain which was heavy on the 9th with 44mm at Liscombe (Somerset). The holiday weekend was probably the cloudiest since 1966. By the 10th a deep depression lay over the northern North Sea, and from then until the 15th the UK lay under a rather cold, showery flow from a northerly quarter. Some of the showers were very heavy, and many were accompanied by hail and thunder, but there were some good sunny intervals as well. The 16th was mostly dry with long sunny spells.
                                                                                                                                             
    TEMPERATURE   SUNSHINE   RAINFALL        
                                                                                                                                     
                                                                                                                                     
                                  Highest and lowest totals             Highest and lowest totals        
                                  on record for month    
Maximum fall in 24 hrs
   (beginning 09 h)
        on record for month    
Days with snow or sleet
 
Days with fog
(Vis <220 yards at 09 h)
 
                                                                                         
     
Difference from average
   
Difference from average
 
Highest maximum
   
Lowest minimum
   
No. of days with grass
  minimum below 0C
   
Days of no sunshine
 
Maximum duration
       
First year of record
         
Days of no rainfall
 (0.1 mm or less)
         
First year of record
         
Days with thunder
     
  PLACE  
Mean Maximum
   
Mean minimum
             
No. of air frosts
       
Total for month
                   
Total for month
                   
                               
% of average
                   
% of average
                 
                                                                     
                                   
Highest
   
Lowest
 
Year
             
Highest
   
Lowest
 
Year
       
             
Date
   
Date
         
Date
         
Year
         
Date
         
Year
           
                                                                     
    C     C     C     C           Hrs     Hrs       Hrs     Hrs       mm     mm       mm     mm          
                                                                                                                                             
  *Hampstead   12.3   -0.3   04.0   -0.6   17.5   30   -01.2   06   13   02   02   11.1   01   136   099   1910   240   1912   087   1920   04   36.1   28   * 147   280   1910   123   2000   02   1912   03   00   00  
  *Thorney Island   12.2   -1.6   04.7   -0.4   16.6   30   -00.5   02   13   03   00   12.5   16   178   097   1956   269   2011   101   1966   08   17.0   24   * 116   225   1941   111   2000   00   2007   06   00   00  
  *Wattisham   11.6   -0.8   03.6   -0.2   17.3   30   -02.8   06   10   04   03   11.9   01   130   088   1968   254   1990   123   2006   04   17.6   28   * 117   264   1960   109   1998   02   2007   04   00   00  
  *Wittering   11.3   -0.8   03.6   -0.5   17.5   30   -02.5   06   06   03   04   11.5   01   109   070   1950   221   1984   077   1978   07   25.0   04   135   293   1948   142   1998   03   2011   05   00   00  
                                                                     
  *Lyneham   11.5   -0.8   03.4   -0.9   16.7   30   -02.8   06   11   03   03   11.9   01   119   071   1952   243   1984   084   1961   05   21.2   29   125   242   1946   153   2000   01   1984   03   00   00  
  Ross-on-Wye   12.1   -0.5   04.1   -0.9   16.9   30   -01.7   06   11   05   03   10.9   15   150   097   1915   229   2007   072   1920   08   14.2   24   117   233   1859   173   2000   00   1957   03   00   00  
  *St Athan   11.1   -1.2   05.0   +0.2   14.7   30   00.0   06   09   00   04   11.5   01   128   071   1954   253   1984   091   1966   06   29.8   30   * 156   258   1954   125   2000   02   1957   01   00   00  
  Culdrose   11.1   -0.5   05.0   -0.9   13.3   08   01.6   06   06   00   01   11.5   15   175   096   1961   248   1984   127   1966   05   21.6   24   129   212   1961   152   1998   09   1984   00   00   00  
                                                                     
  *Edgbaston   10.5   -1.1   04.4   -0.1   16.4   30   00.7   15   08   00   01   10.6   01   144   107   1887   242   2007   091   1891   08   14.6   28   100   144   1887   137   1998   02   1938   04   00   00  
  *Valley   10.7   -1.1   05.1   -0.5   17.5   30   00.8   06   09   00   05   12.0   05   145   074   1946   247   1974   123   1996   12   12.4   16   065   110   1941   103   1961   07   1980   00   00   00  
  *Woodford   10.4   -1.6   03.4   -0.5   17.4   30   -03.4   15   13   04   05   11.2   30   * 089   065   1945   216   1984   095   1961   04   17.6   11   * 141   248   1942   107   2001   04   1980   02   00   00  
  *Watnall   10.8   -1.3   03.9   -0.2   17.4   30   -00.7   16   06   02   06   11.9   01   093   059   1948   220   1984   071   1971   07   28.0   03   * 140   307   1942   135   2000   03   2011   07   00   00  
                                                                     
  *Leeming   10.7   -1.4   02.5   -1.4   14.4   08   -02.7   05   15   08   06   12.6   05   * 085   059   1945   222   2011   088   1971   10   19.2   25   107   240   1945   140   2000   02   2011   05   00   00  
  *Boulmer   09.4   -1.1   04.4   +0.5   13.7   08   -00.4   05   05   01   06   10.2   05   117   075   1945   218   1984   083   1974   08   21.8   25   118   258   1945   156   1998   03   1980   01   00   00  
  *Eskdalemuir   09.1   -1.6   01.1   -0.8   11.8   22   -04.4   05   18   08   03   07.1   05   082   057   1911   198   2011   059   1996   06   18.6   09   095   097   1911   254   1947   17   1980   03   03   01  
  *Bishopton   11.3   -1.0   02.8   -0.9   14.2   11   -03.7   05   13   05   01   11.2   15   126   076   1921   205   1962   073   1937   09   14.0   09   066   116   1921   159   1947   05   1974   01   00   00  
                                                                     
  *Leuchars   10.0   -1.4   02.8   -0.8   15.2   01   -03.0   05   16   07   02   12.6   28   103   060   1922   217   1990   098   1937   07   30.6   02   098   221   1922   117   1934   02   1938   00   00   00  
  *Dyce   08.7   -2.1   02.9   0.0   13.2   08   -01.6   05   10   04   08   10.1   16   * 071   045   1941   212   1942   085   1941   00   15.0   29   121   212   1941   131   2000   10   1946   00   00   00  
  *Stornoway   09.5   -0.8   03.5   -0.4   12.5   20   -01.1   16   10   04   02   13.6   18   149   089   1880   230   1962   095   1944   07   17.4   16   085   113   1943   144   1947   01   1974   00   00   00  
  *Aldergrove   10.7   -1.5   03.1   -1.2   15.9   30   -01.4   15   16   02   02   11.2   12   141   089   1927   220   1974   057   1937   12   13.2   16   059   108   1927   117   1986   06   1938   02   00   00  
                                                                     
                                                                                                                                             
  Stations marked with an asterisk record sunshine electronically; comparisons      
  with earlier records are therefore somewhat speculative. Thorney Island's   * New low record   * New high record  
  sunshine figures are from a nearby site.      
  Reference period now 1981-2010