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graphs CLIMATE-UK.COM'S REVIEW OF THE BRITISH METEOROLOGICAL SCENE
MONTHLY SUMMARY
No. 619 For JULY 2007
COOL, VERY WET, AND DULL. SERIOUS FLOODING ON THE SEVERN AND THAMES
Text Box: Depressions tracked across the Atlantic Ocean and Europe close to latitude 60 degN almost without a break, maintaining very unsettled weather throughout the month. Sea-level pressure was below normal over practically the whole of Europe with an anomaly centre of -8mbar over southern Sweden. Over the British Isles this was the fifth most cyclonic July in 134 years of records.

Cyclonic activity was at its most vigorous between the 1st and 6th, but a weak ridge affected southern Britain on the 7th/8th before a changeable west to northwesterly flow returned from the 9th-12th. Showers were frequent and heavy up to the 6th, and were widely accompanied by hail, thunder and squally winds, with gusts approaching 50kn reported locally; there were also several reports of funnel clouds and minor tornadoes. Stonyhurst (Lancs) recorded 115mm of rain during the first six days of the month. The next two days were quieter with sunny periods, but the morning of the 8th was cold with local ground frost. It was cloudier again from the 9th with showery rain in most areas.

Between the 13th and 16th lowest pressure lay in the Southwest Approaches and a warm and humid southerly flow affected mainly eastern England, the temperature climbing to 25.7C at Charlwood (Surrey) on the 15th, and falling no lower than 17.9C at St Jamess Park (London) the following night. Other areas were cloudy with rain at times. Lowest pressure transferred north-eastwards across the country on the 17th and 18th, maintaining the changeable weather but it became warm briefly again on the 19th with a high of 25.5C at Gravesend (Kent).

A depression which formed over France on the 19th moved very slowly northwards along the Greenwich Meridian  on the 20th and 21st to be off Aberdeen early on the 22nd. Rain was widespread, heavy and prolonged, especially in southern England, the Midlands and Lincolnshire, and upwards of 50mm fell over a wide area. Totals in
Text Box: excess of 100mm were registered across at least 2500 sq km of Oxon, Glos, Worcs, Herefs, north Wilts and south Warwicks, with 48h totals of 157mm at Pershore Agric. College and 128mm at Brize Norton. There was immediate short-lived surface flooding, followed by severe flooding over the following week along the lower Severn and the upper Thames. This was the biggest summer rainfall event since 26th August 1986, the worst flood on the Severn between Bewdley and Gloucester since March 1947, and the worst summer flood here since 1886. In Scotland, clear skies and light winds allowed the temperature to drop to 0.5C at Kinbrace (Sutherland) early on the 20th, and the maximum the next day at Aviemore was just 9.7C.

The next depression tracked along the English Channel bringing heavy rain to southern England on the 22nd/23rd (45mm at Scilly), but northern Britain was fine and Prestwick (Ayrshire) recorded 15.1h of sunshine on the 23rd. A further depression brought heavy rain and strong winds to most regions on the 25th/26th. Southern England was again wet overnight 28th/29th, but the month ended with two days of fair but cool weather as a small anticyclone crossed the country; nights were particularly cold with minima of 2 to 6C recorded widely.

Mean maximum temperature for the month was between 0.5 and 2 degC below the long-term average in all regions, while mean minimum temperature was within 0.5 degC of the norm, and it was the coolest July over the country as a whole since 1993. Rainfall was well above average in most regions except for parts of northern and western Scotland, and five times the normal amount fell in the Pershore district; averaged nationally it was the wettest July since 1936. Sunshine duration was above normal in parts of western Scotland, Northern Ireland and locally in the south Midlands, but it was well below average in northeast Scotland, northeast Wales and Lancashire; over the country as a whole it was the dullest July since 1998 and locally in northeast Scotland it was the dullest on record.
                                                                                                                                               
    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   20.6   -0.9   12.4   -0.4   23.3   19   09.0   31   00   00   00   09.8   31   155   084   1910   321   1911   109   1913   13   22.4   20     089   189   1910   193   1924   05   1921   02   00   00  
  Thorney Island   19.8   -2.5   13.2   0.0   22.1   24   09.3   30   00   00   01   13.7   31   192   085   1958   336   2006   153   1978   09   15.4   19     089   206   1941   122   1945   06   1949   01   00   00  
  *Wattisham   20.7   -0.4   11.6   0.0   23.4   16   07.3   30   00   00   01   09.8   30   159   084   1968   295   1976   131   1978   11   12.6   03     059   138   1960   101   1987   05   1977   04   00   00  
  *Wittering   19.6   -1.0   11.8   -0.1   22.6   16   07.7   31   00   00   03   12.8   31   160   085   1955   283   2006   115   1965   08   26.0   20     084   189   1955   153   2004   06   1977   05   00   00  
                                                                       
  Lyneham   18.8   -2.2   11.3   -0.7   22.2   19   08.0   31   00   00   03   14.2   24   190   088   1952   314   2006   129   1965   08   35.8   20     * 149   346   1945   125   1950   04   1955   05   00   00  
  Ross-on-Wye   19.6   -1.6   11.7   -0.6   23.0   12   06.0   31   00   00   05   14.5   07   208   111   1915   311   2006   095   1944   11   52.5   20     161   368   1859   197   1872   06   1935   03   00   00  
  *St Athan   17.9   -2.3   12.7   +0.2   21.2   19   08.7   31   00   00   05   14.2   07   179   084   1954   319   1955   131   1965   09   23.2   19     160   269   1954   168   1965   13   1977   02   00   00  
  St Mawgan   17.2   -1.8   12.8   -0.2   19.8   31   09.8   31   00   00   05   14.7   30   201   094   1945   317   1955   111   1954   04   12.8   09     094   173   1944   143   1988   01   1955   02   00   00  
                                                                       
  *Edgbaston   18.7   -2.7   12.0   -0.8   23.2   12   09.3   22   00   00   04   13.1   10   146   084   1887   285   1990   067   1888   06   62.4   20     * 183   389   1887   167   1936   07   1911   06   00   00  
  *Valley   17.2   -1.7   12.9   +0.4   19.2   19   09.7   31   00   00   03   14.0   31   184   091   1946   341   1955   115   1986   09   19.0   13     099   209   1941   114   1957   09   1983   02   00   00  
  *Woodford   18.2   -1.7   11.3   0.0   21.8   19   07.5   10   00   00   03   12.6   31   109   065   1945   280   2006   102   1954   06   26.0   04     132   207   1942   187   1973   10   1999   05   00   00  
  *Watnall   18.8   -1.8   11.7   -0.2   22.0   12   08.4   10   00   00   04   13.9   31   154   082   1948   273   2006   087   1965   09   24.2   26     132   296   1942   148   1973   11   1982   06   00   00  
                                                                       
  *Leeming   19.5   -0.9   11.1   -0.5   21.9   16   06.3   10   00   00   02   13.2   31   158   095   1945   276   2006   091   1965   11   17.6   02     094   223   1947   139   1973   09   1984   05   00   00  
  *Boulmer   18.2   -0.1   10.8   -1.0   22.0   16   07.2   10   00   00   01   12.4   08   132   074   1945   268   1955   105   1957   10   11.6   15     086   180   1945   118   1988   07   2006   01   00   00  
  *Eskdalemuir   17.2   -0.9   09.1   -0.1   19.8   24   04.6   23   00   00   01   09.9   30   098   066   1911   266   1989   075   1931   04   31.2   13     168   190   1911   269   1988   25   1913   03   00   00  
  *Bishopton   18.6   -0.8   10.4   -0.4   21.4   24   06.3   23   00   00   03   13.0   23   137   079   1921   297   1989   086   1931   13   31.8   13     087   152   1921   147   1988   11   1984   02   00   00  
                                                                       
  *Leuchars   18.4   -0.6   10.4   -0.4   22.0   17   07.0   30   00   00   04   12.1   09   139   073   1922   262   1955   091   1931   09   29.2   21     119   220   1922   181   1940   13   1983   01   00   00  
  *Dyce   17.2   -1.1   11.0   +0.9   22.5   31   06.9   09   00   00   05   14.9   09   103   063   1941   263   1955   078   1968   09   16.0   13     108   177   1941   198   1957   13   2003   01   00   00  
  *Stornoway   15.8   -0.3   11.2   +0.8   19.6   09   07.4   29   00   00   03   14.9   20   112   082   1880   227   1917   057   1939   14   19.0   01     080   134   1943   165   1988   14   1955   00   00   00  
  *Aldergrove   17.9   -0.9   11.0   -0.2   20.4   25   06.6   29   00   00   01   12.4   23   135   094   1927   274   1955   086   1986   08   21.6   16     104   134   1927   155   1950   12   2000   02   00   00  
                                                                       
                                                                                                                                               
  Stations marked with an asterisk record sunshine electronically; comparisons      
  with earlier records are therefore somewhat speculative. Thorney Island's     * New high record  
  sunshine figures are from a nearby site.