CLIMATE-UK.COM'S REVIEW OF THE BRITISH METEOROLOGICAL SCENE

MONTHLY SUMMARY

No. 565

For JANUARY 2003

A TWO-FACED MONTH

Text Box: Two cold spells from the 4th-12th and the 29th-31st were separated by a lengthy mild interlude. Mean sea-level pressure anomalies ranged from -1 mbar in Shetland to +3 mbar in western Ireland, and the anomalous flow over the UK was weakly northerly.

The very wet weather at the end of December lasted until the 3rd as active depressions crossed southern Britain, and there was flooding on several rivers in southern England. Kenley (Surrey) collected 99mm of rain in the six days ending 09GMT on the 2nd. In Scotland, meanwhile, snow fell widely on the 1st. High pressure centred over or near northern Britain from the 4th to the 11th brought cold and mostly dry weather with long sunny periods. However, troughs in the northeasterly airflow over England and Wales brought some snow, chiefly to the eastern half of England between the 6th and 8th. Some 8-12cm of snow fell in southwest Essex and northwest Kent - the most in the area since early-December 1997. Very severe frosts occurred in Scotland and Northern Ireland, and on the 8th Aviemore reported a minimum of -18.6°C and a maximum of -8.8°C.

The anticyclone slipped southwards into France during the 11th-12th, allowing a broad southwesterly flow to encroach over the British Isles. Sunny but frosty weather lasted longest in the Southeast, and Redhill airfield reported -9.9°C early on the 12th, but northern Britain became mild and rainy. It stayed cloudy and mild until the 18th with prolonged heavy rain over west-facing slopes especially in Scotland, including a fall of 73mm in 48hr at Dalmally (Argyllshire)

Text Box: on the 12th-13th. Gusts over 70kn were recorded in Scotland on the 15th. A deep depression drifted slowly east across England and Wales bringing four days of heavy rain between the 18th and 21st, but a strong rise of pressure thereafter provided a few days of quieter weather.

Moist southwesterlies were quickly re-established and Dalmally collected a further 82mm of rain in 48hr on the 24th-25th. During the 26th and 27th air originating near Bermuda lifted temperatures to 12-14°C generally, and several degrees higher to the lee of high ground where a pronounced foehn effect occurred. On the 26th Aboyne (Aberdeenshire) recorded 18.3°C, equalling the UK record for January and establishing a new Scottish record, while 16.1°C at Silent Valley (Down) was a new record for Northern Ireland. The following day, East Malling (Kent) reached 17.4°C, a new January record for England. On the 28th and 29th the flow veered northerly bringing a decided drop in temperature and widespread wintry showers. Snow fell widely in eastern regions on the 30th with falls of 15-20cm in northeast Scotland, while a sudden fall of 8-12cm in north London precipitated gridlock on the capital's roads and stranded some commuters for over 12 hours.

Mean monthly temperature was generally within 1 degC of the 1971-2000 average. Rainfall, averaged nationally, was close to normal, but eastern counties were generally wet while some western districts were quite dry. Except locally in northern Scotland it was a sunny month, and the total of 121.6 hr at Weymouth (Dorset) is a new January record for the UK.

TEMPERATURE

SUNSHINE