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graphs CLIMATE-UK.COM'S REVIEW OF THE BRITISH METEOROLOGICAL SCENE
MONTHLY SUMMARY
No. 573 For SEPTEMBER 2003
DRY, SUNNY AND WARM UNTIL THE LAST WEEK
Text Box: High pressure covered the UK until the 5th, and again mid-month, but there were unsettled interludes around the 6th-11th, 18th-22nd, and 27th-30th. Overall, mean monthly pressure over the British Isles was 3 to 5 mbar above the long-term normal.

High pressure built across Britain from the west on the 1st. This anticyclone drifted slowly eastwards over the next few days and a cold front approached from the Atlantic on the 5th. The first five days of the month were mostly fine and it became very warm with 27C in London on the 5th, but by this time rain had set in across western Scotland and Northern Ireland. Fronts crossed the UK at intervals between the 6th and 11th bringing cooler, cloudier weather with occasional rain and local thunder. Some of the rain was heavy in western regions but amounts in most eastern districts were derisory.

Another anticyclone developed over England on the 12th and, although the main centre quickly transferred to eastern Europe, high pressure held sway across southern Britain until the 21st. The 12th was a fair, fresh day, but much of the country became sunny (after the clearance of early-morning fog patches) and very warm from the 13th onwards, the temperature widely reaching 24-27C with 28.4C at Gravesend (Kent) on the 17th, and 24C as far north as Altnaharra (Sutherland) the same day. There were excellent displays of medium- and high-level instability clouds on the 14th-16th. Significant rain was confined to northwest Scotland for a while, but heavy rain affected much of northern Britain between the 18th and 22nd; 48mm fell at
Text Box: Saughall (Ayrshire) on the 21st alone.

A marked cold front swept southeast across the whole of the UK on the 22nd, bringing the first appreciable rain to Beds, Herts, and Cambs since 31 July. In East Anglia and the Southeast the temperature fell 8 degC in a few minutes at the frontal passage and the following night snow showers whitened slopes in the Scottish Highlands above 500m. A new anticyclone travelled east acrss southern Britain over the next few days bringing sunshine by day but frost at night. The minimum of -3.5C at Kindrogan (Perthshire) on the 24th was the UK's lowest in September for ten years, while readings of -1 to -3C in southern England were locally the lowest since 1919. Changeable weather returned for the remainder of the month, but amounts of rain were again small in many areas.

Mean monthly temperature was generally 0.4-1.0 degC above the 1971-2000 norm, but there was a marked contrast between warm days and cool nights, such that for central England it was the warmest September by day since 1959 and the coldest by night since 1993. Apart from scattered locations in the north and west it was a dry month, exceptionally so in southern England where Bognor Regis (Sussex) collected only 3mm. Over England and Wales it was the driest September since 1997. Sunshine was well above average almost everywhere, and at Manston (Kent) the month's total of 256 hours was 56 per cent above the local average. Over England and Wales it was the sunniest September since 1964.
                                                                                                                                           
    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   21.4   +3.0   10.4   -0.1   27.3   17   04.0   24   02   00   00   10.2   04   183   141   1910   224   1959   072   1945   22   11.4   22   022   032   1910   157   1918   02   1959   00   00   00  
  Thorney Island   20.6   +1.4   10.0   -1.0   25.1   16   03.3   24   00   00   00   11.2   04   221   132   1958   245   1959   129   1967   24   03.2   22   009   017   1941   159   1974   02   1971   00   00   00  
  *Coltishall   20.5   +2.6   07.5   -2.8   26.7   18   02.4   24   02   00   00   11.6   08   * 220   152   1979   205   1979   082   2001   22   08.2   09   021   041   1964   154   1994   08   1969   01   00   00  
  Wittering   20.4   +2.7   09.2   -0.5   26.7   17   03.2   24   02   00   00   11.1   17   183   133   1950   207   1964   093   1967   22   14.8   22   024   051   1948   132   1992   02   1959   01   00   00  
                                                                     
  Lyneham   20.1   +2.6   09.8   +0.2   26.1   17   03.4   24   04   00   03   11.5   04   174   122   1952   235   1959   100   1983   25   09.6   22   014   021   1945   142   1974   05   1959   00   00   01  
  Ross-on-Wye   20.7   +2.8   08.6   -1.1   27.0   17   01.0   24   05   00   04   10.3   04   170   133   1914   205   1929   069   1945   19   07.1   22   012   019   1859   203   1976   02   1865   00   00   00  
  *St Athan   19.3   +1.9   10.6   -0.1   24.9   17   03.7   24   01   00   04   11.4   04   143   099   1954   249   1959   074   1956   18   08.8   08   024   027   1954   223   1974   14   1959   00   00   00  
  St Mawgan   18.6   +1.5   11.7   +0.3   23.2   17   06.0   24   00   00   02   12.0   02   195   124   1945   258   1959   080   1956   19   08.4   08   031   039   1944   179   1974   10   1959   00   00   00  
                                                                     
  *Edgbaston   19.8   +2.8   10.3   +0.3   25.9   17   02.8   24   02   00   03   10.9   16   160   126   1887   216   1895   067   1909   19   08.4   22   032   058   1887   165   1918   04   1959   00   00   00  
  Valley   17.3   +0.5   11.6   +0.4   21.3   17   05.4   27   00   00   02   11.3   13   143   102   1946   214   1949   096   1948   13   25.2   19   090   108   1941   174   1950   03   1986   00   00   00  
  Ringway   18.9   +1.8   09.8   -0.3   24.9   17   03.6   27   01   00   01   11.1   14   145   119   1945   197   1959   069   1948   16   12.0   22   045   060   1942   171   1965   05   1959   00   00   00  
  *Watnall   19.6   +1.9   09.6   -0.1   25.8   17   04.0   27   00   00   00   11.4   17   169   122   1948   177   1991   075   1993   22   08.6   06   025   054   1942   147   1957   02   1959   01   00   00  
                                                                     
  Leeming   19.0   +1.7   08.2   -1.0   25.0   17   02.5   24   03   00   01   10.4   14   161   135   1945   200   1986   073   1976   19   38.2   20   063   129   1945   174   1976   04   1959   01   00   01  
  *Boulmer   17.9   +1.6   09.1   -0.2   24.5   17   03.7   24   01   00   02   10.0   10   141   112   1945   205   1986   075   2001   17   10.0   21   042   077   1945   147   1965   12   1971   00   00   00  
  Eskdalemuir   15.6   +0.7   07.4   +0.3   20.2   04   -00.6   24   04   01   05   10.8   03   113   115   1911   153   1959   055   1980   10   29.4   21   084   059   1911   308   1950   18   1972   01   00   00  
  *Bishopton   16.6   +0.3   08.8   +0.1   21.0   04   02.5   23   01   00   04   11.8   10   124   112   1921   169   1996   068   1965   07   24.2   07   071   075   1921   258   1985   11   1972   00   00   00  
                                                                     
  Leuchars   18.2   +2.0   08.9   +0.2   23.5   17   02.8   11   03   00   00   12.7   10   153   121   1922   181   1997   077   1956   15   18.6   21   043   084   1922   149   1950   05   1972   00   00   00  
  Dyce   17.3   +1.8   08.1   +0.1   22.8   17   02.2   24   06   00   03   09.9   12   147   128   1941   171   1997   070   1968   15   06.7   21   027   041   1941   234   1995   15   1959   00   00   00  
  *Stornoway   14.9   +0.7   09.7   +1.0   18.1   03   03.5   23   01   00   05   09.8   14   084   079   1880   175   1903   070   1965   09   19.4   07   109   106   1943   206   1981   34   1968   00   00   00  
  *Aldergrove   16.8   +0.7   09.7   +0.3   21.6   13   04.5   27   00   03   01   08.2   24   109   085   1927   177   1986   070   1962   09   34.4   21   083   114   1927   163   1981   06   1986   00   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 made at a nearby site.