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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 597 For   SEPTEMBER  2005
A  VERY  WARM  MONTH;   FAIRLY  SUNNY  AND  DRY  BUT  UNSETTLED  TOWARDS  THE  END
Text Box: High pressure lay close to southern Britain for much of the month, although the focus of anticyclonic activity moved to eastern Europe during the third and fourth weeks allowing a changeable southwesterly type to become established over the UK. Mean sea-level pressure ranged from 1mbar below normal in Shetland to 2mbar above in eastern England, with a weak south to southwesterly anomalous flow covering the country. A cold front crossed the UK on the 1st but a large anticyclone developed the next day, subsequently drifting towards the Baltic and allowing thundery troughs to cross Britain on the 4th/5th. A cut-off depression in the Southwest Approaches controlled the weather from the 8th-11th but pressure rose sharply again on the 12th. The period 1st-10th gave England and Wales its warmest start to September since 1949. Maxima of 24-26°C were reported widely; the high of 29.7°C at Northolt (London) on the 4th was the highest for this month in the UK since 1999, while the maximum of 27.4°C at Charterhall (Berwickshire) was the highest in Scotland since 1991. The night of the 3rd/4th was widely the warmest in September since 1949, the temperature falling no lower than 20.4°C at Guernsey airport and 19.5°C at Pembrey Sands (Carmarthen). There were some thunderstorms on the 4th and 5th, but prolonged heavy rain affected southern Scotland and northern England on the 8th-9th, and thunderstorms broke out widely further south on the 9th and 10th, with an unofficial report of 70mm at Danbury (Essex). Although it remained warm in the extreme Southeast, most districts became cooler on the 9th and 10th, and in Scotland it was much colder: Kinbrace (Sutherland) recorded a minimum of -3.5°C on the morning of the 9th, the lowest anywhere in the UK so early in the season since 1986, while the max that day at Salsburgh (Lanarkshire) was just 9.8°C. Most regions became fine again briefly around the 11th-12th.
Text Box: From the 13th-24th a changeable westerly type affected most of the UK, although high pressure was never far from southern districts. There was a short-lived northerly incursion around the 16th. During the last week the European high retreated, and a vigorous southwest to westerly type dominated. A deep depression, formerly hurricane ‘Maria’, delivered prolonged heavy rain to the north and west of Scotland on the 12th-13th, Broadford (Skye) collecting 131mm and Aultbea (Wester Ross) 85mm in 48h. Widespread rain on the 14th-15th was followed by a brief northerly outbreak with a maximum of 9.3°C at Lerwick (Shetland) on the 16th and air frost as far south as the Thames Valley on the morning of the 17th. Shap (Cumbria) recorded -1.7°C. From 19th-24th all parts of the UK had changeable weather, but further heavy falls of rain in the highlands and islands contrasted with very small amounts in southern England. There was another frost early on the 24th. The remainder of the month was very unsettled with frequent rain in all areas; a vigorous cold front on the afternoon of the 28th triggered tornados in County Antrim (two), and Lancashire. A brief tropical-maritime incursion led to a warm and muggy day on the 30th with highs of 20-22°C. Mean temperature was 1 to 2 degC above the long-term average in all regions, and it was generally the warmest September since 1999 and, as measured by the CET, the fifth warmest in the last 100 years - only those of 1929, 1949, 1961 and 1999 were warmer. In spite of the very unsettled last week, rainfall was below normal, except in parts of northern and western Scotland, northeast England and East Anglia. Monthly totals below 25mm were reported from Royal Deeside, and from Wiltshire and Dorset. There was a small sunshine deficit in the north and west of Scotland and in Northern Ireland; elsewhere sunshine aggregates were 10-20 per cent above normal, and over 30 per cent above in the southwest Midlands.
                                                                                                                                           
                       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