Home / Weather News /

A weatherbomb - Storm Barra's explosive cyclogenesis

12:00
7 December 2021

A weatherbomb
Storm Barra's explosive cyclogenesis

barra windsStrong winds continue to batter Ireland with strengthening winds affecting the UK this afternoon.

Ahead of slamming into Ireland with strong winds and torrential rainfall this morning, Storm Barra underwent something called explosive cyclogenesis. But what is this?

Cyclogenesis happens with an area of low pressure undergoes rapid intensification with explosive cyclogenesis occurring when pressure drops at least 24 millibars within 24 hours.

Storm Barra saw its central pressure drop from 1010 millibars at noon on Monday to 959 millibars at noon today. That’s more than twice the threshold to meet the explosive criteria!

Barra’s explosive cyclogenesis occurred because of an interaction with the jet stream – a ribbon of fast moving air around 5-8 kilometres high in the atmosphere.

As Barra got caught up in the jet stream, the area of low pressure was able to suck in more air making the system spin faster and lowering its pressure rapidly.

The best known cyclogenesis or ‘weatherbomb’ to hit Ireland was the Fastnet Rock storm in August 1979 where the pressure dropped by 40 millibars in 24 hours leaving 15 sailors dead.

More on the topic
Wind radar and warning map for strong gusting winds across south-east Ireland, Wales, and the English south coast.
Tuesday 15 July 2025

For UK and Ireland

Pressure system prompts wind warnings
Wednesday 9 July 2025

30°C in London

Summer comeback in the UK
sunny
Friday 11 July 2025

Safety first

Tips for the current heatwave!
All weather news
This might also interest you
Two weather radars side-by-side, one showing sunny conditions over the UK and the other a temperature map showing widespread warmth.
Thursday 10 July 2025

Breakfast brief

Turning sunnier and warmer
Monday 14 July 2025

Breakfast brief

Turning gusty as temperatures ease
Tuesday 8 July 2025

Breakfast brief

Sunny in the east, overcast in the west
All articles
Weather & Radar

www.weatherandradar.ie

facebooktwitteryouTubeContact uslinkList
Privacy Policy | Legal info | Accessibility statement