Areas affected

• Southern England
• Channel Islands
• S Wales
• S Midlands
• Parts of E Anglia
• Channel Islands

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Hazards

• Isolated tornadoes
• Wind gusts to 70mph (higher on south coast)
• Occasional CG lightning
• Hail

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Discussion

A very deep Atlantic low, named Storm Ciarán by the UK Met Office, will cross southern parts of the UK later tonight and on Thursday. Very strong winds will affect parts of the south of the UK, along with the Channel Islands. These strong 'gradient winds' are handled by warnings from the Met Office and the Channel Islands Met Service.

This outlook is concerned with the risk of one or two tornadoes from convection associated with the storm, especially on the cold front of the system. Modest instability will overlap with very strong low-level shear across the area, starting over the SW of England this evening, and then progressing eastwards towards E Anglia early tomorrow morning. Instability will tend to decrease inland, and the northern extent of the risk is somewhat uncertain.

The highest risk of one or two tornadoes would likely be along and south of a line from S Wales to London, but the risk cannot be ruled out a bit further north too, hence the Watch box extending into the Midlands and E Anglia.

Very strong gusts may accompany some of the showery activity - and occasional CG lightning is possible, most likely near the south coast. Also, the strongest cells may produce some small hail.

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Last updated by RPK at 16:34 GMT Wednesday 1st November 2023