The rapidly intensifying “bomb cyclone” is moving northwest, forecast to hit the UK on the afternoon of 24 November before turning southeast and weakening over Scotland on 25 November.
The UK Met Office named this "bomb cyclone" Storm Bert, following local custom.
In the United States, federal agencies only recognize names for tropical storms, not non-tropical storms. Europe records 10 to 20 strong non-tropical storms each year.
The name Bert is part of a naming system chosen by Met Eireann - the Irish government's weather forecasting agency, the UK's Met Office and KNMI - the Dutch national weather forecasting service.
The Washington Post notes that this is the time when "bomb cyclones" or rapidly intensifying low-pressure systems form in the oceans.
A "bomb cyclone" has just blown into the Pacific Northwest, bringing strong winds and up to 300mm of rain to the mountains of Northern California, USA. Another "bomb cyclone" is forming in the northeast Pacific.
For a “bomb cyclone” to form, technically, the air pressure must drop to a certain threshold within 24 hours. In a case of Hurricane Bert’s scale, the threshold for air pressure drop is 22.1 millibars in 24 hours.
However, Storm Bert – which appeared at the same latitude as Dublin – is expected to see its pressure drop from 988 to 948 millibars in 24 hours, almost double the level needed to qualify as a “bomb cyclone”.
Due to the influence of "bomb storm" Bert, on the morning of November 23, in Ireland, the wind suddenly appeared and moved south-southeast, with gusts of up to 96 km/h. Snowfall was recorded early on November 23 in the UK, after which the wind also began to form.
Wind gusts of 70 to 90 km/h are forecast across England and Wales on 23 November. This could lead to disruption to flights in London. London’s Heathrow Airport is one of the world’s busiest, so any disruption caused by Storm Bert could impact air travel across Europe.
Scattered snowfall was reported in Liverpool, Manchester and Leeds from the evening of 22 November as a result of the latest "bomb cyclone". However, heavier than expected snowfall was recorded further north, with 15-20cm of snow falling in Scotland.
Forecasters in Europe note that snow will change to rain from south to north on the morning of November 24 as warmer air moves into the region. Much of the snow that fell on the afternoon of November 22 will melt quickly.
It is forecasted that during this "bomb storm", scattered rain will occur throughout November 23 and last until the morning of November 24.
