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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 600 For   DECEMBER  2005
      HEAVY RAIN EARLY AND LATE, OTHERWISE QUIET AND VERY SUNNY
Text Box: Cyclonic conditions prevailed during the first week and the last three days, otherwise December was a mainly anticyclonic month. Cold weather was confined to a brief northerly outbreak around the 17th and a northeasterly episode between the 26th and 29th. Mean monthly sea-level pressure was 2 to 5 mbar above normal throughout the UK, and the anomalous flow over the country was northeasterly. A deep depression (central pressure 961mbar at landfall near Plymouth early on the 2nd) tracked across the country from Devon to Northumberland during the 2nd and 3rd, slowly filling, before transferring southwards into the continent over the next few days. The first three days of the month were very unsettled with heavy rain and local thunder, and 79mm of rain fell at Cardinham (Cornwall) in 48 hours. Southerly gales and high spring tides combined to cause coastal flooding along the Channel coast, and the railway line at Dawlish (Devon) was damaged. Following the November cold spell it became milder for a few days, but a rather cold northeasterly flow set in during the 5th and 6th and there was a widespread frost early on the 7th ahead of a further belt of rain. Strong rises of pressure on the 8th marked the beginning of a long anticyclonic spell. Highest pressure lay over the near continent at first, over the British Isles from the 11th-13th, thence retrogressing to mid-Atlantic and allowing a northerly to develop briefly on 16th-17th. After a frosty start on the 8th, Scotland and Northern Ireland became exceptionally mild with maxima approaching 14°C on each of the next three days, and overnight minima of 10°C or higher. Much of England and Wales, meantime, was less mild with night frosts and sunny days: Hastings (Sussex) logged 8.0 hours of bright sunshine on the 9th. The settled weather continued for several more days, and on the 12th the barometer reached 1046.9 mbar at Castlederg (Tyrone); a preliminary search indicates that this may have been the highest sea-level pressure in the UK since January 1992, and the highest in December since 1980. As the anticyclone retreated, a cold front swept southwards on the 16th introducing a short-lived northerly outbreak
Text Box: which brought snow showers to northern and eastern districts and a couple of sharp frosts: Aboyne (Aberdeenshire) recorded -8.8°C early on the 18th. Highest pressure returned to France from the 18th-23rd, with a rather mild westerly air-stream covering the UK. Most places stayed dry but cloudy. An anticyclone developed over the UK on the 24th and 25th, moving to Scandinavia on the 26th and introducing four days of very cold northeasterly winds. Snow showers fell widely in eastern and central districts between the 27th and 29th, and although most falls were slight to moderate, some 30cm of level snow accumulated over the North Downs between Ashford and Dover. Some western areas, meanwhile, remained dry and very sunny, and at St Mawgan (Conrwall) a total of 29 hours of bright sunshine was logged during the four days 25th-28th. The temperature fell to -12.8°C at Aviemore (Inverness-shire) overnight 28th/29th, and climbed no higher than -3.9°C at Durham during the 29th. Atlantic fronts advanced eastwards across the country on the 30th; snow was heavy for a time in northeast England, but the snowed turned to rain in all areas as temperatures climbed briskly. Highs of 13°C were noted in Wales and the West Country. Mean monthly temperature was close to the long-term average in most parts of the UK - slightly above in Scotland and Northern Ireland, slightly below in southern England where it was the coldest December for four years. Rainfall was below average practically everywhere, with less than half the normal in parts of northern and western Scotland, Cumbria, Yorkshire, Lincolnshire and East Anglia, while at Portland (Dorset) there was no significant rain between the 8th and 28th inclusive. Sunshine totals were near normal in northern and eastern Scotland and in Northern Ireland, but well above average everywhere else, and excesses of 80% occurred locally in southern England, the north Midlands and Yorkshire. Over England and Wales it was the fourth sunniest December on record, after 1886, 1962 and 2001, while November and December were the sunniest such pairing since records began.
                                                                                                                                         
                       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