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graphs      CLIMATE-UK.COM'S  REVIEW  OF  THE  BRITISH  METEOROLOGICAL  SCENE
     MONTHLY  SUMMARY
     No. 604            For    APRIL    2006
THE MOST 'WESTERLY' APRIL SINCE 1977.  VERY DRY IN EASTERN SCOTLAND & SOUTHWEST ENGLAND
Text Box: A northwesterly type lasted until the 11th, but winds were often southwesterly during the middle and latter parts of the month. Blocking was largely absent over northwest Europe and the northeastern Atlantic. With sea-level pressure 12mbar below normal to the north of Scotland and 2mbar above over France, this was the most ‘westerly’ April over the British Isles since 1977. A complex depression crossed the country on the first two days of April bringing outbreaks of rain followed by showers, including a fall of 36mm on the 2nd at Capel Curig (Snowdonia). But there were also good sunny intervals in most regions, and temperatures were well up to the seasonal average. It turned appreciably colder between the 3rd and 11th as the wind swung into the north and night frosts occurred widely; the temperature fell to -6.4°C at Katesbridge (Down) overnight 5th/6th and to -6.9°C at Tulloch Bridge (Lochaber) overnight 9th/10th, while the maximum reading on the 7th was just 2.9°C at both Loch Glascarnoch (Wester Ross) and Dalwhinnie (Inverness-shire). Many days brought sunshine and showers, and the showers often fell as hail, sleet and snow, and on the night of the 9th/10th heavy snow fell for several hours in Kent, Sussex, Surrey and parts of London. Some 5-10cm accumulated over land above 150m, and there were credible reports of around 12cm in the Tunbridge Wells, East Grinstead and Crowborough districts with damage to trees, telephone and power lines. East Malling (Kent) recorded a rainfall equivalent of 31mm. Sunshine was plentiful with aggregates for the 1st-10th running 50-75 per cent ahead of the norm. Winds backed westerly from the 12th-18th and although the weather remained changeable it became warmer (especially by night) and less sunny. Rain fell frequently, but amounts were generally small except over west-facing slopes where Kinlochewe (Wester Ross) recorded 39mm on the 12th and Cassley (Sutherland) 39mm in 48 hours on the 16th-17th. Text Box: Between the 19th and 26th winds were mainly southwesterly although they backed easterly on the 21st as a cut-off depression slipped southwards from Ireland to Biscay, the associated rain largely confined to Cornwall and Devon. Most districts were warm and rather humid on the 21st with 21°C at St Helier (Jersey) and 19.7°C at Herstmonceux (Sussex) and it remained warm in the Southeast on the 22nd but temperatures were lower thereafter. A good deal of fog was reported early on the 24th in central and southern districts. An anticyclone west of Ireland dominated from the 27th-29th and all parts of the UK were dry with sunny periods; nights were cold and locally frosty, and in most areas days were cool although central Scotland was warm on the 29th with 18.9°C logged at Aberfeldy (Perthshire) on this date contrasting with just 7.2°C at Thorncliffe (Staffs) on the 30th. An active frontal system advanced eastwards across the UK on the night of the 30th bringing widespread rain, and substantial snow fell above 600m in the Scottish highlands. Mean monthly temperature was 0-0.5 degC below normal in northern and western Scotland, but up to 1 degC above in all other regions; nevertheless this was the coolest April generally for five years. The absence of warm days was a notable feature: for the first time since 1986 nowhere in the UK had reached 20°C by 30 April. Rainfall distribution showed a strong orographic modulation as one would expect in a very westerly month, percentages ranging from over 150 in northwest Scotland to little more than 10 in eastern parts of Fife and Angus, and around 20 in east Devon. Sunshine percentages ranged from 130 or more in Shetland, southeast Scotland and Northumberland to below 90 locally in East Anglia, the east Midlands, and southeast England. Lerwick (Shetland) had it sunniest April since 1970, while at Leuchars (Fife) it was arguably the sunniest since records began in 1922 (the recent change in sensor means that exact comparisons are now impossible).
                                                                                                                                           
                       TEMPERATURE                                SUNSHINE                             RAINFALL