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graphs CLIMATE-UK.COM'S REVIEW OF THE BRITISH METEOROLOGICAL SCENE
MONTHLY SUMMARY
No. 688 For APRIL 2013
COLD TILL THE 12TH, THEN MOSTLY RATHER WARM 13TH-25TH, THEN RATHER COLD AGAIN; MOSTLY DRY AND QUITE SUNNY
Text Box: had 64mm on the 17th; over the five-day period from the 13th to the 18th Cluanie Inn collected 209mm. There was a notable sandstorm during the 15th-16th in northeast Scotland between Forres and Nairn, notably along the A96 road close to Culbin Sands where visibility dropped below 50m at times; strongest winds however were recorded on the 18th with gusts to 73kn at Aberdaron (Caernarfon).  It became briefly colder in eastern England on the 19th, but the 20th was a sunny day after widespread early frost. The next two days were rather changeable, but with only small amounts of rain in eastern, central and southern England. 

Warm weather resumed over much of England and Wales between the 23rd and 25th with highs exceeding 20C locally though the weather remained changeable in Scotland and Northern Ireland; the highest temperature during this spell was 23.0C at St James's Park (London) on the 25th. The wind swung into the northwest on the 26th, and the remainder of the month was rather cold, quite windy in northern districts, and there were sharp showers of rain, hail and sleet, with hill snow. The lowest maximum during this period was 5.6C at Altnahinch (Co Antrim) on the 26th and slight to moderate frost occurred on several nights. On the 30th 14.2h of bright sunshine was measured at Morecambe (Lancs).

Mean temperature during April was between 0.5 and 1.5 degC below the 1981-2010 normal in all regions; as measured by the CET the month was fractionally warmer than April last year, but in scattered locations (chiefly in the western Britain) it was actually the coldest April since 1989. In the last 100 years 19 Aprils were colder. Except in western and northern Scotland it was a dry month - remarkably so in northeast England, Yorks, Lincs, south Lancs and Cheshire, where Nantwich (Cheshire) recorded just 4mm of rain. Sunshine duration was above normal except in southwest England and south Wales; an aggregate of 238 hours was measured at Tiree (Argyll).
Text Box: With two contrasting weather types during the month, mean pressure was not far from normal during April. Averaged over the entire month a gentle southwesterly flow covered the UK, while the anomalous flow was weakly south to southwesterly. Pressure anomaly ranged between -3 mbar in Shetland and the Western Isles and +1 mbar in East Anglia and Kent.

The cold easterly flow so prominent in late-March continued during the first eleven days of April over the greater part of the UK. Snow flurries occurred in eastern Scotland and northeast England during the first three days, and there was slight but persistent snow in the East Anglia and southern England on the 4th and at first on the 5th; some very low maxima were observed, including 0.5C on the 1st at Lake Vyrnwy (Montgomeryshire) and 1.2C on the 4th at Wych Cross (Sussex), while overnight lows hit -11.2C at Braemar (Aberdeenshire) early on the 2nd. The easterly relaxed for one day - the 7th - under the influence of a ridge of high pressure, but some heavy snow showers were observed in northern Scotland on this day with a high of just 1.3C at Loch Glascarnoch (Wester Ross). The second week of April was slightly less cold, though much of England and Wales was cloudier with outbreaks of rain (and hill snow) in southern districts, while there were wintry showers in eastern Scotland. However, western Scotland remained very sunny with 109.3h of bright sunshine during the first ten days at Tiree (Argyllshire). Remains of old snow-drifts persisted until the 12th as far south as the Chilterns and Cotswolds.

A disturbed south to southwesterly airstream prevailed between the 13th and 17th bringing much higher temperatures; amounts of rain in East Anglia and the Southeast were very small, but there was much wind and rain in northern and western parts. On the 14th the temperature reached 22.0C at Swanscombe (Kent) and 21.9C at Lynford (Norfolk). Cluanie Inn (Wester Ross) logged 58mm of rain on the 14th and Lusa (Skye)
                                                                                                                                             
    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   12.1   -0.6   03.9   -0.8   22.1   25   -01.9   02   13   06   00   10.4   20   161   117   1910   240   1912   087   1920   12   10.1   10   036   069   1910   123   2012   02   1912   00   01   00  
  *Thorney Island   10.9   -2.9   04.2   -1.0   17.1   23   -03.2   07   12   05   00   12.9   30   188   102   1956   269   2011   101   1966   16   12.4   10   044   085   1941   111   2012   00   2007   00   02   00  
  *Wattisham   12.2   -0.3   03.2   -0.7   21.8   25   -03.3   07   13   09   01   13.6   20   184   123   1968   254   1990   123   2006   12   06.4   25   029   064   1960   109   2012   02   2007   01   02   00  
  *Wittering   12.2   0.0   03.2   -1.0   20.7   24   -03.6   02   14   09   01   13.1   20   170   109   1950   221   1984   077   1978   21   09.2   25   020   044   1948   142   1998   03   2011   00   01   00  
                                                                     
  *Lyneham   11.4   -1.0   03.3   -1.0   17.1   23   -04.2   03   13   07   03   12.3   02   148   088   1952   243   1984   084   1961   17   09.6   11   030   061   1946   153   2000   01   1984   00   02   00  
  Ross-on-Wye   12.6   -0.1   03.9   -1.2   18.8   23   -03.7   07   14   03   00   10.7   02   179   115   1915   229   2007   072   1920   19   05.0   11   014   029   1859   173   2000   00   1957   00   00   00  
  *St Athan   11.0   -1.4   04.0   -0.9   14.8   15   -02.7   03   13   04   04   12.4   30   150   083   1954   253   1984   091   1966   16   14.6   11   040   069   1954   125   2012   02   1957   00   00   00  
  Culdrose   10.4   -1.3   04.9   -1.1   13.2   30   -00.9   06   10   04   06   12.6   29   148   081   1961   248   1984   127   1966   14   09.6   08   035   058   1961   152   1998   09   1984   00   00   00  
                                                                     
  *Birmingham U   11.5   -0.9   03.2   -0.7   18.6   23   -03.5   07   16   06   00   10.2   20   159   113   1887   242   2007   091   1891   16   02.8   13   013   026   1887   137   1998   02   1938   01   01   00  
  *Valley   10.4   -1.5   04.5   -1.2   12.3   14   -01.6   01   10   05   02   12.8   20   198   101   1946   247   1974   123   1996   14   09.6   13   033   055   1941   103   1961   07   1980   00   00   00  
  *Rostherne   12.2   +0.1   02.5   -1.5   17.8   17   -05.4   07   15   09   02   12.6   06   138   099   1945   216   1984   095   2012   15   05.4   11   019   034   1942   107   2012   04   1980   00   00   00  
  *Watnall   11.8   -0.4   03.4   -0.8   17.8   14   -02.4   02   14   08   01   13.0   20   144   092   1948   220   1984   071   1971   23   05.8   12   012   026   1942   135   2012   03   2011   01   01   00  
                                                                     
  *Leeming   11.6   -0.6   02.4   -1.6   17.6   14   -05.0   03   17   10   03   12.1   29   146   101   1945   222   2011   088   2012   20   03.8   18   013   030   1945   140   2000   02   2011   00   02   00  
  *Boulmer   10.0   -0.6   03.9   -0.1   16.9   14   -00.2   06   08   01   03   13.9   30   170   108   1945   218   1984   083   1974   18   03.0   18   014   032   1945   156   1998   03   1980   00   02   00  
  *Eskdalemuir   08.9   -1.9   01.2   -0.8   11.9   30   -07.2   06   17   11   05   10.0   03   099   069   1911   198   2011   059   1996   12   55.4   17   166   170   1911   254   1947   17   1980   00   04   00  
  *Bishopton   10.3   -2.1   02.9   -0.9   13.3   14   -04.0   03   13   05   03   12.8   19   167   101   1921   205   1962   073   1937   10   20.6   17   100   176   1921   159   1947   05   1974   00   01   00  
                                                                     
  *Leuchars   10.4   -1.1   03.0   -0.7   15.7   15   -04.1   03   17   04   03   12.8   30   177   101   1922   217   1990   098   1937   16   06.8   26   032   071   1922   117   1934   02   1938   00   02   00  
  *Dyce   10.1   -0.9   02.6   -0.4   16.0   22   -03.4   06   14   08   01   11.9   15   138   086   1941   212   1942   085   2012   11   05.4   17   027   049   1941   131   2000   10   1946   00   03   00  
  *Stornoway   09.0   -1.4   02.5   -1.5   11.6   15   -02.9   02   12   08   02   12.6   02   182   108   1880   230   1962   095   1944   07   14.6   13   097   129   1943   144   1947   01   1974   00   01   00  
  *Aldergrove   10.7   -1.6   03.6   -0.8   15.6   14   -03.8   06   09   05   01   12.0   03   164   102   1927   220   1974   057   1937   13   10.0   16   059   107   1927   117   1986   06   1938   00   00   00  
                                                                     
                                                                                                                                             
  Stations marked with an asterisk record sunshine electronically; comparisons      
  with earlier records are therefore somewhat speculative. Thorney Island's      
  sunshine figures are from a nearby site.      
  Reference period now 1981-2010