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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 581 For    MAY    2004
                 CYCLONIC FIRST WEEK, THEN MOSTLY ANTICYCLONIC
Text Box: Pressure was low over the British Isles during the first ten days of May, but high pressure dominated the scene for most of the rest of the month, although Atlantic fronts moved in during the last few days.

A slackening north-easterly flow on the 1st maintained cool, grey weather across southern Britain but it was sunny from the north Midlands northwards, and the 2nd was a fair and pleasantly warm day over much of the UK. A cold front moved south-eastward across the country the following night and stalled across East Anglia and the Southeast on the 3rd (the May Day bank holiday) where it was a cool and wet day. A vigorous Atlantic depression approached Scotland later that day, deepening on the 4th to 971 mbar over central Scotland - probably the lowest May pressure in the UK since 1943 - and further heavy rain crossed the country. The next two days brought widespread showers with hail and thunder as the depression slowly filled up in situ. A belt of rain crossed England from the east on the 8th and the north-easterly wind kept it very cool along North Sea coasts, but Shetland became warm and sunny (Baltasound 20.3ēC on the 9th) thanks to a dry north-easterly off Norway.

That warm air spread to most of the UK over the next few days under a sluggish northerly flow, the temperature reaching 23.7ēC at Glentress (Peebles) on the 10th, but thunderstorms broke out widely from the Scottish
Text Box: Highlands to the English Channel. It turned cooler temporarily during the next few days, but from the 14th to the 19th most parts of the country were fine and warm with long sunny periods, the temperature widely reaching the low 20s, and touching 25ēC in London on the 17th and 19th. A southward moving cold front brought showers and a sharp drop in temperature on the 19th/20th, but much of the UK became sunny again during the following week although there was widespread ground frost at night; at Kinbrace, Sutherland, the air minimum on the 27th was  -3.7ēC. There were a few well-scattered showers on the 25th/26th, but an eastward-moving occlusion brought the first measurable rain for 22 days to parts of west Wales, Cornwall and Devon on the 28th. The next few days were rather cloudy and showery, and on the 31st (the late spring bank holiday) a belt of rain advanced slowly across the West Country and Wales, but most other regions stayed fair until late.

Mean maximum temperatures were 1-2degC above the 30-year average, while mean minima were 0.5-1.5 degC above, and it was generally the warmest May for three years.  Rainfall was slightly above average in parts of East Anglia and the Southeast, but below in all other regions, and Leeming, North Yorks, recorded only 15mm. Sunshine totals were below normal in northern Scotland and locally in East Anglia and the Midlands, but well above average elsewhere; a few sites in Cornwall and Devon had their sunniest May since 1989 with aggregates of over 300 hours locally.
                                                                                                                                         
                       TEMPERATURE                                SUNSHINE                             RAINFALL                                                       
                                                                                                                                 
                                                                                                                                 
                   
No. of days with grass
  minimum below 0ēC
                      Highest and lowest totals    
Maximum fall in 24 hrs
   (beginning 09 h)
                Highest and lowest totals    
Days with snow or sleet
 
Days with fog
(Vis <220 yards at 09 h)
 
     
Difference from average
   
Difference from average
             
Days of no sunshine
                      on record for month                         on record for month        
                                                                                         
           
Highest maximum
   
Lowest minimum
         
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
           
                                                                     
      ēC       ēC       ēC       ēC             Hrs       Hrs         Hrs       Hrs       mm       mm         mm     mm          
                                                                                                                                         
  *Hampstead   17.5   +1.7   08.5   +0.3   23.9   19   03.7   22   00   00   01   11.9   19   174   089   1910   297   1989   112   1932   20   13   03   047   085   1910   124   1979   04   1989   00   00   00  
  Thorney Island   16.7   +0.1   08.5   +1.0   21.7   20   03.5   02   01   00   01   13.9   19   220   097   1958   322   1989   151   1981   16   15   20   047   112   1941   103   1946   04   1989   01   00   00  
  *Coltishall   15.9   +0.7   07.4   +0.5   23.2   17   02.8   28   00   00   02   13.4   27   187   089   1990   285   1992   141   1996   20   13   03   034   089   1964   088   2000   08   1980   00   00   00  
  *Wittering   16.5   +1.3   07.5   +0.9   22.0   16   02.9   23   00   00   03   13.4   19   157   078   1955   299   1989   133   1969   18   13   07   052   110   1955   116   1983   09   1990   01   00   00  
                                                                     
  Lyneham   17.0   +1.6   08.2   +1.6   22.4   17   03.3   22   00   00   02   13.7   18   218   109   1945   288   1990   112   1981   19   09   31   033   057   1945   139   1967   05   1990   02   00   00  
  Ross-on-Wye   18.1   +2.4   08.0   +0.8   24.0   17   01.0   07   03   00   01   14.0   19   202   109   1915   285   1992   104   1932   15   09   04   031   054   1859   158   1967   05   1896   02   00   00  
  *St Athan   16.2   +1.2   08.5   +1.2   20.9   16   03.5   07   00   00   02   14.1   18   232   114   1954   318   1990   119   1981   19   11   31   030   051   1954   155   1983   05   1991   02   00   00  
  St Mawgan   15.4   +1.3   09.5   +1.5   21.1   16   06.7   06   00   00   02   15.0   24   266   121   1956   297   1990   125   1981   22   08   03   027   046   1956   149   1981   07   1991   01   00   00  
                                                                     
  *Edgbaston   16.6   +1.2   08.7   +1.7   22.7   17   04.0   22   01   00   01   11.9   19   167   093   1887   263   1997   094   1954   17   08   31   037   064   1887   173   1932   05   1896   01   00   00  
  Valley   14.9   +0.6   08.5   +0.7   20.0   27   04.6   22   00   00   02   14.2   16   253   113   1946   306   1977   161   1970   22   12   03   036   067   1941   127   1993   10   1970   00   00   00  
  Ringway   16.8   +1.4   08.0   +0.7   22.1   16   03.3   07   00   00   01   14.3   23   196   106   1945   258   1989   111   1991   19   09   04   046   081   1942   144   1967   08   1991   01   00   00  
  *Watnall   16.9   +1.7   08.0   +1.4   22.4   16   03.3   22   01   00   03   12.7   18   157   078   1948   276   1989   085   1983   17   14   07   052   117   1942   135   1969   11   1991   00   00   00  
                                                                     
  Leeming   16.8   +1.8   06.2   -0.1   22.0   16   01.1   22   05   00   01   14.3   16   215   122   1945   238   1980   103   1983   20   03   07   015   031   1947   106   1983   09   1959   00   00   00  
  *Boulmer   14.3   +1.8   06.9   +1.1   21.0   15   02.1   27   03   00   02   15.4   27   195   111   1945   231   1989   098   1983   24   07   07   027   054   1945   151   1924   07   1992   00   00   01  
  Eskdalemuir   15.5   +1.9   05.5   +1.0   20.5   10   -01.0   05   09   03   00   14.1   23   202   123   1911   268   1935   079   1969   15   24   03   063   070   1911   257   1986   04   1984   02   00   00  
  *Bishopton   16.6   +1.6   07.1   +1.1   22.4   10   01.4   22   02   00   01   13.6   23   172   092   1921   266   1975   098   1983   17   14   03   047   078   1921   156   1925   07   1991   02   00   00  
                                                                     
  Leuchars   15.6   +2.2   06.6   +0.8   20.9   15   00.0   03   03   00   00   14.1   16   211   113   1922   256   1942   095   1969   21   09   04   031   064   1922   152   1969   14   1959   00   00   00  
  Dyce   14.4   +1.6   07.2   +2.1   21.3   15   01.0   27   02   00   03   15.2   27   194   112   1941   256   2001   086   1983   16   08   20   023   040   1942   152   1969   14   1994   00   00   01  
  *Stornoway   13.5   +1.3   06.9   +0.9   18.0   30   02.2   01   01   00   03   13.5   27   161   086   1880   294   1994   093   1944   12   11   03   040   067   1943   145   1986   19   1978   01   00   00  
  *Aldergrove   15.4   +0.7   07.0   +0.9   20.2   16   00.8   07   02   00   01   15.4   22   182   093   1927   295   1946   115   1933   21   10   04   024   048   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 made at nearby Hayling Island.