A depression which formed over France on
the 19th moved very slowly northwards along the Greenwich
Meridian on the 20th and 21st to be off Aberdeen early
on the 22nd. Rain was widespread, heavy and prolonged,
especially in southern England, the Midlands and Lincolnshire,
and upwards of 50mm fell over a wide area.
Totals in excess of 100mm were registered
across 400-500 sq km of Oxon, Gloucestershire, Worcestershire,
Herefordshire, North Wiltshire
and South Warwickshire, with 48 hour totals of 157mm at
Pershore Agricultural College and 128mm at Brize Norton.
There was
immediate short-lived surface flooding, followed by severe
flooding over the following week along the lower Severn
and the upper Thames. This was the biggest summer rainfall
event since 26th August 1986, the worst flood on the Severn
between Bewdley and Gloucester since March 1947, and the
worst summer flood here since 1886. Lyneham received its
record monthly rainfall of 149mm beating the previous wet
record month of 1945 where 125mm fell. The downpour
of 2007 was 346 percent of the July monthly average
and the traditional summer month was even 2.2C down on
the mean
monthly maximum at 18.8C. The temperatures were kept down
by rain filled skies and the sunshine levels were down
too. Only 127 hours was recorded 88 per cent of the 30
year average, a record low, compared with the record high
total of 314 hours sunshine in 1952. |
