Severe weather

The Met Office provides national severe weather warnings in association with the Home Office Emergency Planning Division. These are posted on the Met Office web site. In addition, announcements are made via the Met Office's forecasts on the BBC and ITV.

The Met Office can produce accurate weather forecasts for anywhere in the world, including the oceans. As one of only two World Area Forecast Centres (the other one is in the USA), the Met Office is also responsible for the high-level forecasts that safely route all commercial aircraft over Europe, Asia, Africa and Australasia.

More about the Met Office worldwide

The Met Office has a responsibility to forecast and disseminate warnings of severe weather. These include warnings of heavy rainfall, which are sent to the Environment Agency in England and Wales, SEPA in Scotland and various government departments in Northern Ireland. More-detailed daily forecasts are also transmitted for inclusion in flood forecasting models.

Recently, the Met Office has developed new tools for improving flood warning (EnviroMet) and there have been notable improvements in the accuracy and resolution of radar information, also used in rainfall forecasting. The Met Office has recently improved its ability to estimate soil moisture content: a critical component in assessing flood risk.

The Environment Agency has a new National Flood Warning Centre. The Environment Agency's Floodline can be contacted on 0845 988 1188.

A tornado will typically last for a few minutes, track across the land for two to five kilometres (roughly one to three miles) and will have a diameter of 20 to 100 metres (22 to 110 yards). Wind speeds are in the order of 72 to 113 m.p.h. but can reach 200 m.p.h.

In contrast, a hurricane is an intense area of low pressure that only forms in the tropics where the sea-surface temperature is at least 27 °C. A hurricane has a diameter of around 150 km (about 100 miles), mean wind speeds that average at least 73 m.p.h. (by definition) and can last for several days. In the western Pacific they are called 'typhoons', and in the Indian Ocean they are called 'cyclones'. Collectively, hurricanes, typhoons and cyclones are known as tropical cyclones.

Tropical cyclones are among the most powerful and destructive meteorological systems on Earth. Globally, 80 to 100 develop over tropical oceans each year. The Met Office produces tropical cyclone forecast guidance twice per day based on its global numerical weather prediction model forecasts for all current storms, and has a record of being one of the most accurate forecasting units for these events.

The Met Office tracks these storms all over the world and is among the top five weather organisations for worldwide forecasting. It also provides forecasts to hurricane forecasting centres worldwide, including the National Hurricane Center in Miami, Florida, where it is the only non-US forecasting service used in the United States.

More about Met Office tropical cyclone forecast guidance

More about hurricanes

Tropical cyclones are named to provide ease of communication between forecasters and the general public regarding forecasts, watches and warnings. Since the storms can often last a week or longer, and more than one can be occurring in the same basin at the same time, names can reduce the confusion about which storm is being described.

The names are all predetermined in alphabetical order, alternating between male and female. The web site FAQ: hurricanes, typhoons and tropical cyclones provides all the hurricane names for the next four years and gives historical information on hurricane names.

The Great Storm of 1987 did not originate in the tropics and so was not a hurricane — but it was certainly exceptional. In the Beaufort scale of wind force, hurricane force (Force 12) is defined as a wind of 64 knots or more, sustained over a period of at least 10 minutes. Gusts, which are comparatively short-lived (but cause much of the destruction), are not taken into account. By this definition, hurricane-force winds occurred locally, but were not widespread.

More about the Great Storm of 1987

YES: Lightning often strikes twice in the same place — sometimes several times. High buildings, chimneys, power lines and radio masts are often struck more than once during a single thunderstorm.