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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 634 For   OCTOBER  2008
CHANGEABLE WITH HEAVY OROGRAPHIC RAIN;  WARM SECOND WEEK, BUT EXCEPTIONALLY WINTRY FINAL WEEK
Text Box: This was the most westerly October since 1986, and the ninth most westerly in 136 years of records. There was a cyclonic bias during the first week, an anticyclonic one during the second week, and the month ended with an Arctic outbreak of rare severity for the season. A vigorous northwesterly flow during the first three days brought rather cold but bright weather to all districts, although there were also blustery showers which were wintry over the Scottish hills. A deepening depression crossing northern Scotland resulted in a wet and windy day on the 4th and it was cold enough in Shetland (max 5.3°C at Baltasound) for snow at low levels for a time; a secondary disturbance crossing southern districts meant that the rain lasted for much of the 5th here too. Capel Curig (Snowdonia) recorded 90mm in 24h, the culmination of a six-day wet spell which delivered 233mm. Colder, clearer northwesterlies returned during the 5th bringing 10.5h of sunshine to Berwick (Northumberland) and the following night was frosty even in southern England. A further rain-belt crossed all areas on the 7th. Pressure now rose strongly across southern Britain although a moist southwesterly flow continued to affect Scotland. Most southern, central and eastern parts enjoyed five days of warm and sunny weather from the 8th till the 12th although morning fog was slow to clear from some areas. The temperature approached or exceeded 20°C quite widely on the 11th and 12th, peaking at 22.9°C at Stratfield Mortimer (Berks) and Broadness (Kent) on the latter date. The 13th was cloudier but still quite warm with 21.4°C at Manston (Kent). Throughout this period rain fell frequently and heavily in northern and western districts resulting in some flooding; Dundrennan and Threave (both Kirkcudbrightshire) each collected 85mm in 48h on the 9th-10th. Temperatures returned to the seasonal normal over the next few days, and after a few days of cloudy skies it became much brighter again in southern and eastern districts between the 16th and 18th. The following week was very disturbed especially in western and northern regions as three intense depressions passed close to northern Scotland on the 19th-20th, the 23rd, and the 25th. Gales swept exposed coasts and hills with peak gusts of 81kn at
Text Box: Lerwick and 77kn at Fair Isle onthe 25th. The rain associated with each of the systems was heavy and prolonged over west-facing coasts and slopes, and a combination of heavy rain and rough winds brought about the cancellation of the two-day Lake District marathon on the 25th, with many competitors having to be rescued. On that day alone 92mm fell at Capel Curig and 80mm at Shap (Cumbria). In the wake of the last of these depressions, winds veered northerly during the 26th-27th, ushering in a brief Arctic outbreak of unusual severity for October. At first, snow showers were confined to Scottish coasts and hills with remaining regions enjoying long sunny periods. On the 28th, however, a shallow depression travelled southeastwards across England, bringing a period of rain and sleet which turned readily to snow as a renewed surge of Arctic air engaged the rear of the disturbance. Some 3 to 5cm of snow fell over hillier parts of the Midlands and over the Chiltern Hills, with 7cm at Whipsnade (Beds). This was quite possibly the heaviest and most widespread October snowfall in southern Britain since 1880. The day’s high at Dalwhinnie (Inverness-shire) was just 0.9°C, and that night the mercury fell to –6.6°C at Topcliffe (North Yorks). Further rain and hill snow fell in Northern Ireland and western Britain on the 29th in association with a southward moving depression, and that night an exceptional thunder and hailstorm struck east Devon leading to serious flooding in the Otter valley. Dunkeswell (Devon) collected 78mm of rain and hail, but it is possible that as much as 120-150mm may have fallen locally. Strong northeasterly winds maintained the cold weather during the last two days of the month. Mean temperature was between 0.5 and 1.5degC below the 1971-2000 mean in most parts of the country, with the larger anomalies in Scotland and Northern Ireland, and averaged nationally it was the coldest October since 2003. Frequent orographically-enhanced rainfall meant that some western upslopes recorded 250 per cent or more of the long-term average, while the rain-shadow districts of northeast England had little more than 50 per cent. Sunshine was plentiful, especially in eastern and central parts of both England and Scotland, and excesses of 25-35 per cent were typical in East Anglia and the Southeast.
                                                                                                                                             
                       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