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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 584 For   AUGUST   2004
  VERY WET WITH FREQUENT THUNDER; HOT FIRST WEEK THEN PROGRESSIVELY COOLER
Text Box: Pressure was almost uniform over the British Isles during the first week, but a cyclonic type prevailed from the 8th-25th followed by almost a week of westerlies. Overall, this was the eighth least westerly and the ninth most cyclonic August in the last 100 years. Mean sea-level pressure anomaly ranged from -1mbar in Shetland to -8mbar in southwest Ireland.

The hot weather of late-July continued until the 8th with maxima of 26-30ēC daily in southern, central and eastern districts, peaking at 31.5ēC at Northolt (London) on the 8th, and the temperature climbed as high as 27ēC even in northern Scotland on the 2nd. The night of 8th/9th was abnormally warm with several local records broken: at Marham, Norfolk, the minimum was 21.7ēC. However, haar affected North Sea coasts and the Northern Isles, and Lerwick had no sunshine for seven consecutive days to the 4th. Thunderstorms broke out widely on the 3rd and 5th; worst hit areas included London and the Thames valley, the Midlands, northwest England and southwest Scotland. Eskdalemuir collected 61mm on the 3rd, and High Wycombe 42mm in 40 minutes the same afternoon. Large hail was reported from Bracknell on the 5th.

A deep depression (in part ex-hurricane Alex) lay to west or southwest of the UK from the 8th-11th before crossing the country on the 12th/13th. A new depression settled west of Ireland from the 14th-18th, and yet another (ex-hurricane Charley) tracked along the English Channel on the 18th/19th. Throughout this period the weather was very disturbed, thundery, and often humid. Prolonged heavy rain affected all except northern Scotland between the 8th and 11th, during which period 100mm-plus fell widely; Aberfeldy recorded 143mm and serious flooding ensued. Over the next several days rainfall was mainly convective in
Text Box: character, and a fall of 200mm (nearly all in four hours) at Ottersham, north Cornwall, led to the catastrophic flash flood at Boscastle on the 16th. Short-lived tornadoes were observed on several occasions. Further notable falls of rain included 62mm at Camborne, Cornwall, on the 17th; 82mm at Lerwick, Shetland, on the 18th/19th, and 56mm (mostly in one hour) at Thurleigh, Beds, on the 20th.

On the 20th a northerly airstream set in temporarily behind a cold front, the day's maximum at Wilsden (West Yorks) was 12.7ēC, and under a short-lived ridge of high pressure the temperature dropped to -0.8ēC at Tulloch Bridge, Lochaber, overnight 21st/22nd. A depression tracked north-eastwards across the UK between the 23rd and 25th bringing further widespread rain followed by heavy thundery showers but for the remainder of the month the depression track shifted to the north of Scotland, with westerly and north-westerly winds over the UK. Gusts to 70kn were reported from northern Scotland on the 27th, but several places in eastern and southern England ended the month with four dry days. The 31st was dry and sunny almost everywhere.

The main feature of August's weather was its exceptional wetness. Over England and Wales there has been none wetter since 1956; monthly totals exceeded 300mm locally in southern Scotland and northern England, and a few sites here collected more than three times the long-term average. By contrast, several places in northern Scotland were drier than normal. Sunshine was generally close to the long-term mean, and in Shetland it was a very sunny month, but central and south-east Scotland together with northeast England reported a shortage. In spite of the cool last ten days, mean temperature was everywhere above average, typically by 1-2 degC, and the CET was the 12th highest in the 345 year-long record.
                                                                                                                                             
                       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   23.2   +1.9   14.4   +1.0   30.8   08   09.5   31   00   00   00   11.5   07   163   076   1910   282   1995   104   1958   11   22   09   124   181   1910   184   1975   02   1995   05   00   00  
  Thorney Island   22.0   +0.2   14.9   +1.7   27.5   08   09.3   31   00   00   00   11.8   01   213   092   1958   303   1976   143   1968   9   23   18   120   260   1941   141   1960   04   1976   04   00   00  
  *Coltishall   21.9   +1.1   13.9   +2.0   27.4   07   08.8   22   00   00   02   12.5   08   * 148   078   1979   290   1995   149   2002   11   14   12   105   201   1964   160   1996   04   2004   06   00   00  
  Wittering   22.1   +1.6   13.5   +1.7   30.1   08   08.2   28   00   00   01   13.5   07   198   104   1950   258   1995   090   1971   12   76   09   * 162   290   1948   123   1956   03   1983   08   00   00  
                                                                     
  Lyneham   21.8   +1.3   13.2   +1.5   28.1   08   08.1   31   00   00   00   13.5   07   194   097   1952   297   1995   125   1958   10   23   03   093   160   1945   136   1951   02   1995   04   00   00  
  Ross-on-Wye   22.6   +1.6   13.5   +1.5   28.2   08   08.0   28   00   00   00   11.8   01   211   117   1915   307   1995   107   1922   11   19   12   086   156   1859   202   1878   04   1936   06   00   00  
  *St Athan   20.8   +0.7   14.0   +1.6   26.9   01   08.6   21   00   00   01   12.4   31   164   076   1954   325   1995   133   1958   11   20   12   096   128   1954   202   1997   22   1955   03   00   00  
  St Mawgan   19.8   +0.7   14.3   +1.2   25.9   01   10.6   31   00   00   01   12.8   07   210   097   1945   323   1976   125   1958   11   22   17   117   187   1944   189   1958   04   1981   03   00   00  
                                                                     
  *Edgbaston   21.6   +1.7   14.0   +2.1   29.1   08   10.4   31   00   00   00   12.2   07   158   090   1887   282   1995   085   1896   11   27   09   135   253   1887   173   1912   06   1940   07   00   00  
  Valley   19.8   +0.8   14.2   +1.6   28.2   02   08.7   31   00   00   00   13.0   01   187   092   1946   291   1976   123   1948   12   24   22   088   146   1941   210   1956   05   1959   02   00   00  
  Ringway   21.3   +1.2   14.0   +1.9   29.3   08   07.9   21   00   00   02   12.8   01   158   091   1945   284   1995   089   1948   6   30   09   185   160   1942   201   1956   07   1976   07   00   00  
  *Watnall   21.6   +1.1   13.4   +1.6   29.2   08   08.9   28   00   00   02   12.5   07   143   076   1948   261   1995   098   1963   13   43   09   * 154   276   1942   152   1956   04   1995   08   00   00  
                                                                     
  Leeming   20.9   +0.6   13.0   +1.8   27.4   07   06.0   21   00   00   03   13.0   08   163   098   1945   246   1995   086   1954   9   39   09   153   196   1945   165   1971   07   1947   06   00   00  
  *Boulmer   17.7   -0.2   12.5   +1.2   23.1   15   07.4   22   00   00   09   10.6   22   * 096   058   1945   273   1995   096   1954   9   35   12   131   190   1945   199   1956   03   1947   01   00   00  
  Eskdalemuir   18.8   +1.0   11.4   +2.3   24.7   08   02.5   26   02   00   06   12.7   21   148   101   1911   260   1947   044   1912   9   62   03   309   295   1911   345   1985   01   1947   04   00   00  
  *Bishopton   19.9   +0.7   12.4   +1.9   24.5   08   05.0   22   00   00   04   12.4   31   117   073   1921   254   1995   085   1942   11   56   10   * 213   298   1921   163   1992   00   1947   03   00   00  
                                                                     
  Leuchars   18.3   -0.2   12.2   +1.7   23.2   06   04.5   22   00   00   07   12.0   31   135   097   1922   242   1995   097   1963   10   35   10   * 213   361   1922   192   1930   07   1955   02   00   00  
  Dyce   17.9   0.0   12.1   +2.2   24.5   15   02.4   22   01   00   05   13.3   22   166   104   1941   257   1947   076   1963   11   26   18   094   138   1941   162   1962   00   1947   01   00   00  
  *Stornoway   17.2   +1.1   12.1   +2.0   24.5   02   06.0   31   00   00   01   14.1   24   147   097   1880   262   1899   075   1942   11   18   14   097   153   1943   203   1982   13   1947   00   00   00  
  *Aldergrove   19.1   +0.6   12.6   +1.7   23.8   02   07.8   28   00   00   05   11.1   01   137   092   1927   276   1976   082   1942   11   13   08   086   131   1927   161   1956   09   1947   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 taken from an adjacent site