Torrential downpours in May, June and July 2007 left large swathes of the country under water as the rain was followed by widespread flooding. By accurately forecasting the weather, the Met Office kept people informed on what they could expect.
Unsettled conditions dominated the Bank Holiday in early May, bringing rain and showers to many parts of the country. For the following Bank Holiday there was heavy rain. After a reasonably dry start to June, extremely heavy and prolonged rain fell on to an already soggy UK, leading to serious floods which threatened lives and caused substantial damage to property. Tragically some people died and thousands more had to spend nights in temporary accommodation or were left without power.
Part of the reason for the heavy rain was the jet stream - a band of strong winds in the upper atmosphere that influence how weather systems that bring rain to the UK will develop. As the jet stream was stronger than normal, depressions near the UK were more intense. Some of these depressions pulled in the very warm and moist air to the south of the UK, generating exceptionally heavy and intense rainfall.
On Monday 25 June prolonged heavy rainfall resulted in many parts of north and east England being flooded.
Map of risk of disruption in June
|17 to 20 June||Localised torrential downpours continued with many Flash warnings issued.|
|21 June||News Release issued to highlight unseasonable weather.|
|22 June||Early Warning issued to public, government and emergency services giving three days' notice of potential disruption.|
|23 June||Further warnings and update to Early Warning issued for E/NE England.|
|24 June||Early Warning updated with highest probabilities for disruption in an arc from Yorkshire and Humberside to the Welsh Borders, with rainfall totals of 'up to 100 mm or so'.|
|25 June||Flash warnings issued for heavy and persistent rain across the high risk areas during the day.|
Surface synoptic analysis map, Monday 25 June at 6pm
Days before the actual flooding, the ground around the worst-hit areas became saturated by very heavy rain. Many sites in Yorkshire received at least a month's rainfall in 24 hours.
On Monday 25 June a slow-moving area of low pressure brought a prolonged period of heavy rain to northern and central England. Hitting the already saturated north-east, the water had nowhere else to go and, as a result, led to major flooding.
A heightened alert state was retained during the week 25-30 June, because of the threat of further rain.
The second event caused localised flash flooding across parts of southern England on the morning of 20 July, and later in the day across the Midlands.
Map of the risk of disruption in July
|16 July||Medium-range computer forecast suggests a vigorous weather system could move toward the UK and engage with relatively warm air over northern France.Met Office Executive Board briefed about the chances of this event.|
|18 July||Early Warning issued in the morning, central and eastern areas of England at risk of disruption from 60-90 mm of rain.|
|19 July||Risk areas narrowed to south-west Midlands, Gloucestershire and Oxfordshire. Possible rainfall total increased to 75-100 mm.|
|20 July||Flash warnings for southern and central England issued before 9 a.m.|
Surface synoptic analysis map, Friday 20 July at 12 UTC.
A slow-moving depression centred over south-east England, drawing warm moist air from the continent across the UK. Heavy and slow moving rainfall moved northwards during the day.