Back To Back Storms Ali and Bronagh hit UK/Ireland in wild September spell, HP settles things down next week!

Written by on September 21, 2018 in Rest of Europe, United Kingdom & Ireland with 0 Comments

It’s turning out to be quite the stormy September with one deepening low after the next lining up to strike the UK. It’s like the atmosphere is playing catch up after the unusually lengthy spell of quiet during the summer.

The flip in the skipping rope goes down to the uptick in global tropical activity which drives tropical heat northwards, tightening the temperature gradient over the mid latitudes thus enhancing the jet stream. Low pressure forms from disturbances along the jet and a dip to the SW of Ireland is where lows have been forming.

A large temperature contrast across both North America and North Atlantic is fueling a particularly powerful September jet stream.


Credit: BBC Weather

Another contributing factor is likely the tight gradient in water temperature of the Atlantic too.

This jet stream is the breeding ground for both formation and speedy intensification of these lows.

It’s Storm Ali was Wednesday’s news and Storm Bronagh took to the stage yesterday bringing heavy rain and another spell of particularly windy weather.

As for Ali, it broke a record in Northern Ireland!


While gusts unsurprisingly exceeded 100, even 110 mph above 3,000ft in the Highlands, the most noteworthy gust was observed at Killowen, Co Down of 91 mph. This in fact becomes Northern Ireland’s strongest September wind gust on record.

As seen from the below map, there were many big gusts exceeding 70 mph including a 72 mph gust at Glasgow Airport.

The Tay Road bridge was forced to close to all traffic as gusts reached 102 mph.

Credit: Russ Hamer

Even as of this mid afternoon writing, Storm Bronagh is already spreading heavy persistent rain across a large swathe of England and Wales, once this shield of rain lifts further north, the same soggy areas will see Bronagh’s windy side.

And once departed the UK, we see the snows arrive on our highest hills!

Storm Bronagh may not have been the strongest of storms nor as strong as it’s predecessor but it continues to tighten and so winds may a problem for Scandinavia this afternoon.

These lows are also acting as a bulldozer sweeping out the warm, humid air and in Germany’s case, record hot air!

After a relatively quiet, fresher Friday, two systems back to back skirt the south coast of England with more heavy rain rather than strong winds. Nonetheless it’s likely to be rough over the open Channel. Good news is it appears we’re settling things down into next week as high pressure builds from the west.







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