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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 569          A CHANGEABLE MONTH WITH A HOT FINISH; DULL AND WET IN THE WEST AND NORTH       For     MAY      2003
Text Box: A changeable southwesterly regime prevailed until the 25th, although there were brief northwesterly interludes around the 14th and 24th. High pressure built across the UK during the last six days of the month. Mean sea-level pressure ranged from 6 mbar below normal off northwest Scotland to 4 mbar above over the Bay of Biscay, resulting in a strongly westsouthwesterly anomalous flow over the British Isles. The first three days of May were very unsettled with outbreaks of rain, heavy locally, but southern, central and eastern districts were warm and sunny on the 4th with highs approaching 23°C. Between the 6th and 10th a showery southwesterly airstream prevailed, with longer periods of rain at times in western and northern regions, and it was windy around the 7th/8th with gusts over 60kn in the Western Isles. Throughout this period eastern England and the Midlands were pleasantly warm and quite sunny with only isolated showers. However, showers broke out more widely between the 11th and 14th as low pressure transferred eastwards across northern Britain, and winds gradually veered northwesterly. Some of the showers were heavy with hail and thunder, but they died down after dark leading to widespread ground frost on several nights. Many places had a moderate air frost overnight 14th/15th, the temperature falling to -4.3°C at Loch Glascarnoch (Wester Ross) and to -3.4°C as far south as Bastreet (Cornwall). The 15th itself was a largely dry and bright day as a ridge crossed the country, and the fine weather continued on the 16th in the far north, with Lerwick (Shetland) enjoying 14.8 hrs of sunshine. Text Box: A disturbed southwesterly weather type returned from the 16th to the 23rd, veering northwesterly on the 24th and 25th. Belts of rain crossed all districts from time to time, with brighter showery weather between; many of the showers were heavy and some brought hail and thunder. There was a general paucity of sunshine during this period, and daytime temperatures were close to or slightly below the seasonal average. A strong rise of pressure began on the 25th, and an anticyclone developed over the British Isles thereafter. It was generally cloudy and rather muggy at times especially in western and northern Britain, but southern and eastern districts became sunnier with maxima around 25°C from the 28th onwards; on the last two days highs of 28-29°C were common and the 31st was the hottest May day since 1953 at several sites in the Midlands and the South. Monthly mean temperatures were around 1 degC above normal in most regions, and 2 degC above in East Anglia and northeast England. Most regions were wetter than average, with more than twice the normal amount of rain locally in southwest Scotland, northern England and north Wales, but it was another dry month in some southern counties (from Devon to Sussex) and in the south Midlands. Sunshine was up to 30 per cent below normal in western Scotland and Northern Ireland, but generally within 10 per cent of average over the rest of the UK.
                                                                                                                                         
                       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 0ºC
   
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
           
                                                                     
      ºC       ºC       ºC       ºC             Hrs       Hrs         Hrs       Hrs       mm       mm         mm     mm          
                                                                                                                                         
  *Hampstead   17.5   +1.2   08.3   +0.7   27.4   31   03.0   13   02   00   01   12.0   04   178   099   1910   297   1989   112   1932   17   08.5   01   044   074   1910   124   1979   04   1989   01   00   00  
  Thorney Island   16.2   -0.4   09.0   +1.5   24.2   30   02.2   13   05   00   02   13.3   29   220   098   1958   322   1989   151   1981   17   11.8   12   041   092   1941   103   1946   04   1989   02   00   00  
  *Coltishall   17.1   +1.9   08.1   +1.2   22.9   31   04.1   13   04   00   01   13.0   28   181   086   1979   285   1992   141   1996   15   11.0   24   047   117   1964   088   2000   08   1980   01   00   00  
  *Wittering   16.9   +1.7   07.6   +1.0   27.1   31   01.9   13   07   00   01   11.6   30   178   089   1955   299   1989   133   1969   15   07.0   25   042   089   1955   116   1983   09   1990   03   00   00  
                                                                     
  Lyneham   15.8   +0.4   07.9   +1.3   26.6   31   02.3   15   07   00   02   14.3   31   204   103   1945   288   1990   112   1981   11   11.0   01   045   078   1945   139   1967   05   1990   01   00   00  
  Ross-on-Wye   16.1   +0.4   08.3   +1.1   27.0   31   01.0   15   05   00   01   13.0   30   219   118   1915   285   1992   104   1932   14   09.4   15   041   068   1859   158   1967   05   1896   03   00   00  
  *St Athan   14.9   -0.1   09.1   +1.8   25.4   30   02.4   15   03   00   01   12.7   30   184   090   1954   318   1990   119   1981   10   26.0   15   092   148   1954   155   1983   05   1991   01   00   01  
  St Mawgan   14.2   +0.1   09.2   +1.2   23.7   30   05.3   15   00   00   03   14.2   29   215   098   1956   297   1990   125   1981   10   26.0   15   081   132   1956   149   1981   07   1991   00   00   01  
                                                                     
  *Edgbaston   16.0   +1.1   08.8   +1.6   26.7   31   01.3   13   05   00   02   12.5   30   181   101   1887   263   1997   094   1954   15   08.4   15   052   091   1887   173   1932   05   1896   03   00   00  
  Valley   14.0   -0.3   09.1   +1.3   22.9   30   05.3   10   00   00   03   13.1   30   181   081   1946   306   1977   161   1970   12   20.6   21   089   159   1941   127   1993   10   1970   01   00   00  
  Ringway   16.1   +0.7   08.4   +1.1   26.6   31   02.4   15   01   00   03   11.8   30   178   096   1945   258   1989   111   1991   10   30.0   19   103   171   1942   144   1967   08   1991   00   00   00  
  *Watnall   16.3   +1.1   07.9   +1.3   27.0   31   02.7   13   04   00   01   12.5   30   146   073   1948   276   1989   085   1983   14   10.8   25   067   143   1942   135   1969   11   1991   02   00   00  
                                                                     
  *Leeming   16.4   +1.4   07.7   +1.4   25.6   31   00.7   10   06   00   01   12.3   31   178   101   1945   238   1980   103   1983   13   09.4   02   051   104   1947   106   1983   09   1959   01   00   00  
  *Boulmer   14.9   +2.4   07.4   +1.6   19.1   29   02.3   10   02   00   02   11.5   31   137   078   1945   231   1989   098   1983   10   22.2   16   078   150   1945   106   1983   07   1992   00   00   00  
  Eskdalemuir   13.2   -0.4   05.7   +1.6   24.1   31   -01.9   10   08   02   03   11.5   14   139   085   1911   268   1935   079   1969   05   23.0   03   127   133   1911   257   1986   04   1984   02   00   00  
  *Bishopton   14.2   -0.8   07.1   +1.1   23.2   31   -00.3   15   05   01   03   12.7   14   118   063   1921   266   1975   098   1983   04   12.8   07   106   169   1921   156   1925   07   1991   01   00   00  
                                                                     
  Leuchars   14.8   +1.4   07.4   +1.6   19.0   29   02.2   10   03   00   02   14.3   08   183   099   1922   256   1942   095   1969   07   06.0   16   058   114   1922   152   1969   14   1959   02   00   00  
  Dyce   14.1   +1.3   06.8   +1.7   21.2   29   01.3   15   05   00   01   13.6   08   199   115   1941   256   2001   086   1983   08   15.2   16   087   145   1942   152   1969   14   1994   00   00   00  
  *Stornoway   12.6   +0.4   06.3   +0.3   19.7   31   -00.2   15   08   01   00   09.3   30   126   067   1880   294   1994   093   1944   04   18.0   07   107   173   1943   145   1986   19   1978   00   00   00  
  *Aldergrove   14.0   -0.2   07.6   +0.6   23.9   30   01.1   15   03   00   04   10.8   14   123   063   1927   295   1946   115   1933   06   14.2   17   107   184   1927   131   1993   07   1991   01   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.