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 27°C 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 24-27°C with 28.4°C at Gravesend (Kent) on the 17th, and 24°C 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 -3.5°C at Kindrogan (Perthshire) on the 24th was the UK's lowest in September for ten years, while readings of -1 to -3°C 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

on record for month

PLACE