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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 605       For     MAY      2006
                     VERY WARM FIRST HALF;  VERY WET SECOND HALF
Text Box: A mainly southeasterly type prevailed for much of the first half of the month, but from the 15th-28th a cyclonic type held sway. The month ended with a short northerly outbreak. Mean sea-level pressure for May was below normal over all parts of the British Isles, anomalies ranging from -0.5mbar in Kent to -3.5mbar along the west coast of Ireland. The trough responsible for the general rain overnight 30th/1st moved quickly away, and with pressure low to the west of Ireland a changeable south to southeasterly flow covered the UK until the 7th. Further rain and strong winds affected Scotland and Northern Ireland on the first two days of the month, but elsewhere the weather was fair if rather cool. It then became much warmer: on the 3rd the temperature reached 21°C in Kent, the UK’s first 20+ maximum of the year and the latest date to cross this threshold since 1983. The 4th was hot and sunny in central and eastern districts with a high of 27.7°C at Northolt (NW London), and this was the earliest date to reach such a high level since 1995, but heavy thunderstorms broke out across central and western Scotland IN the afternoon. The next few days were rather warm but unsettled; heavy rain affected eastern England on the 6th with 42.2mm at Wattisham (Suffolk), and southern counties on 7th with 35.0mm at Swanage (Dorset). High pressure migrating from Scandinavia to Iceland was the dominant feature during the second week, but a thundery trough was never far from southern districts. From the 8th-11th northern Britain was sunny and very warm with 24.8°C at Sloy (Argyll) on the 11th, but sharp thunderstorms affected southern England and south Wales on the afternoons of both the 10th and 11th, and after some warm sunshine with 24.8°C at Northolt, storms broke out more widely on the 12th. Air of Arctic origin now penetrated Scotland and northern England bringing a dramatic drop in temperature, and there was a widespread frost here overnight 13th/14th with a minimum of -5.5°C at Kinbrace (Sutherland). Text Box: A changeable southwesterly type developed from the 15th, and a series of unusually vigorous depressions crossed the UK between the 17th and 22nd bringing frequent heavy rain and unseasonably strong winds, gusting at times to 50-60kn along the English Channel and Bristol Channel coasts. Capel Curig (Snowdonia) collected 124mm of rain during this five-day period. Broadly speaking daytime temperatures were near normal, but nights were often warm especially in southern districts; however, a brief Arctic intrusion resulted in a maximum of just 4.8°C at Boltshope Park (Durham) on the 22nd, and a minimum of -3.9°C at Tulloch Bridge (Lochaber) the following night. Heavy rain returned to southern Britain on the 24th with 43.8mm at Milford Haven (Pembrokeshire). The airflow veered westerly from the 25th-27th, and then northwesterly from the 28th onwards as pressure built strongly, initially to the west of Ireland, and then over the UK as the month closed. The weather became cool and showery, some of the showers accompanied by hail and thunder, and there was widespread ground frost and local air frost by night. Many western districts became dry and sunny from the 28th, and much of Britain was fine on the 31st. A month of two halves, May 2006 is perhaps best summarised as having the warmest first half since 1945 and the wettest second half since 1979. Over the entire month, mean temperature ranged from 1.5 degC above the long-term average in East Anglia and the Midlands to within 0.5degC of the average in Scotland and Northern Ireland. Large parts of England and Wales had twice the normal amount of rain (three times in Pembrokeshire and Kent) but scattered locations in northern and eastern Scotland were slightly drier than normal. It was an exceptionally sunny May in Shetland (a 60% excess at Lerwick) but a very cloudy one in southern and central parts of England and Wales (nearly 30% below locally).
                                                                                                                                             
                       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   17.2   +1.2   09.1   +1.5   26.3   04   04.2   30   00   00   00   11.7   11   139   077   1910   297   1989   112   1932   13   09.3   24   078   134   1910   124   1979   04   1989   01   00   00  
  Thorney Island   16.0   -0.6   09.3   +1.8   20.6   12   04.1   06   02   00   00   13.3   11   203   090   1958   322   1989   151   1981   11   16.2   24   064   144   1941   103   1946   04   1989   00   00   00  
  *Wattisham   16.5   +0.9   08.5   +2.3   24.3   04   04.0   30   01   00   03   13.5   11   * 128   067   1968   331   1989   137   1991   11   42.2   06   * 119   271   1960   102   2000   05   1989   01   00   00  
  *Wittering   16.3   +1.1   08.3   +1.7   25.9   04   03.0   02   01   00   04   13.2   11   153   076   1955   299   1989   133   1969   11   10.2   19   079   168   1955   116   1983   09   1990   01   00   00  
                                                                     
  Lyneham   16.1   +0.7   08.4   +1.8   24.8   04   03.5   02   00   00   03   13.8   11   181   091   1945   288   1990   112   1981   10   19.0   21   122   210   1945   139   1967   05   1990   00   00   00  
  Ross-on-Wye   17.6   +1.9   08.7   +1.5   26.0   04   05.0   02   00   00   00   14.4   31   197   106   1915   285   1992   104   1932   09   16.5   22   106   176   1859   158   1967   05   1896   01   00   00  
  *St Athan   15.4   +0.4   08.8   +1.5   23.0   04   04.1   07   01   00   02   13.4   03   158   078   1954   318   1990   119   1981   09   19.4   24   120   193   1954   155   1983   05   1991   02   00   00  
  St Mawgan   14.0   -0.1   08.9   +0.9   19.1   11   05.7   02   00   00   02   14.8   31   172   078   1956   297   1990   125   1981   11   22.2   24   072   118   1956   149   1981   07   1991   00   00   00  
                                                                     
  *Edgbaston   16.2   +1.2   09.1   +2.1   25.7   04   04.4   23   00   00   00   12.8   11   155   086   1887   263   1997   094   1954   09   16.6   21   089   161   1887   173   1932   05   1896   01   00   00  
  *Valley   14.4   +0.1   08.6   +0.8   20.0   04   04.9   25   01   00   03   13.8   05   176   078   1946   306   1977   161   1970   11   30.2   19   110   196   1941   127   1993   10   1970   01   00   00  
  *Woodford   16.3   +1.2   07.4   +1.0   25.1   04   01.8   23   06   00   01   13.6   11   160   086   1945   258   1989   111   1991   08   11.0   23   090   150   1942   144   1967   08   1991   01   00   00  
  *Watnall   16.4   +1.2   08.3   +1.7   25.9   04   04.2   02   05   00   04   13.6   10   146   073   1948   276   1989   085   1983   09   15.2   21   082   175   1942   135   1969   11   1991   03   00   00  
                                                                     
  *Leeming   15.6   +0.6   06.7   +0.4   23.2   04   02.7   23   07   00   04   14.0   31   174   099   1945   238   1980   103   1983   12   18.0   21   099   203   1947   106   1983   09   1959   01   00   00  
  *Boulmer   13.7   +1.2   06.4   +0.6   18.8   03   01.4   14   03   00   03   14.3   10   196   112   1945   231   1989   098   1983   13   15.4   14   062   118   1945   151   1924   07   1992   00   00   00  
  *Eskdalemuir   13.9   +0.3   04.6   +0.5   21.5   11   -01.9   14   12   05   06   13.5   10   138   084   1911   268   1935   079   1969   09   14.6   21   114   120   1911   257   1986   04   1984   00   00   00  
  *Bishopton   15.2   +0.2   06.0   0.0   23.2   11   01.0   23   12   00   03   13.8   10   180   097   1921   266   1975   098   1983   10   14.4   04   113   179   1921   156   1925   07   1991   00   00   00  
                                                                     
  *Leuchars   13.9   +0.5   05.4   -0.4   18.8   05   -00.6   02   13   01   01   14.7   10   217   117   1922   256   1942   095   1969   11   09.4   17   057   112   1922   152   1969   14   1959   00   00   00  
  *Dyce   13.0   +0.2   05.3   +0.2   19.0   10   00.0   02   09   00   03   13.7   09   166   096   1941   256   2001   086   1983   08   07.0   11   058   097   1942   152   1969   14   1994   00   00   00  
  *Stornoway   12.4   +0.2   06.0   +0.0   17.7   10   01.0   14   06   00   02   13.9   09   175   093   1880   294   1994   093   1944   07   13.6   17   091   146   1943   145   1986   19   1978   00   00   00  
  *Aldergrove   14.5   -0.2   06.9   +0.8   22.0   11   01.1   23   01   00   02   13.8   30   185   094   1927   295   1946   115   1933   10   13.2   16   079   151   1927   131   1993   07   1991   00   00   00  
                                                                     
                                                                                                                                             
  Stations marked with an asterisk record sunshine electronically; comparisons      
  with earlier records are therefore somewhat speculative. Thorney Island's   * New lowest   * New highest  
  sunshine figures are from a nearby site.