11 Aug 2014

Ex-Hurricane Bertha: the view from space

As predicted, the remnants of Hurricane Bertha hit the UK on Sunday, bringing an abrupt end to the warmth and sunshine that we’ve become used to this summer.

The leftovers of the storm were engaged by the jet stream over the Atlantic Ocean, spawning an unseasonably deep area of low pressure that brought a taste of autumn in August.

Much of England and Wales bore the brunt of the bad weather on Sunday, with Scotland and Northern Ireland and northern England continuing to be affected on Monday. 


Whilst the precise path that the low pressure system would take was still uncertain right up until it almost arrived, sufficient notice had been given days in advance, warning of the possible impacts.

Ex-Hurricane Bertha from Space

The remnants of Hurricane Bertha were engaged by the jet stream just to the south west of the UK, forming a developing area of low pressure.

If you look closely at the animation below (courtesy of EUMETSAT), you can see how the low pressure develops quickly from a band of cloud, to a large spiral, as the air spins around the centre of the low pressure system.



Ex-Hurricane Bertha in numbers

On Sunday, England and Wales experienced the greatest amount of rainfall and the strongest winds gusts.

In just six hours, between 10am and 4pm on Sunday, the following amounts of rain were recorded;

Logan Botanic Garden, Wigtownshire – 57.4mm

Normanby Hall, North Lincolnshire – 38.4mm

Leconfield, East Yorkshire – 29.4mm

Top winds gusts during Sunday daytime were;

Needles, Isle of Wight – 64mph

Capel Curig, Gywnedd – 56mph

Isle of Protland, Dorset – 55mph

Overnight, the focus of the heavy rain and strong winds switched to Scotland, with Lossiemouth, Moray having 88.4mm of rain in 12 hours, with a gust of wind reaching 61mph.

Squall line

Another feature of yesterday’s deep area of low pressure was a squall line – a narrow, very intense band of heavy rain, thunder, lightning and gusty winds.

A squally line passed over eastern parts of England on Sunday afternoon and is believed to have caused a tornado in Hull that blew a tree on to a house.

The radar image below from MeteoGroup shows the squall line, depicted by the band of dark blue and white, indicating very intense downpours of rain.


It passed through London at around 2.30pm and can be seen in the video below (courtesy of Digital Urban), lasting 20 minutes before the sunshine returned.

As it moved through west London, I managed to capture a lightning strike.

Warnings still in place

Although the worst is over for many of us, the deep area of low pressure will sit just to the north of Scotland for the next 48 hours.

A weather warning is in place for Scotland for the rest of today, with further heavy downpours of rain expected, as well as strong gusts of wind – both of which will have the potential to cause some localised disruption.

For the rest of us, it’ll be quite gusty for the next day or so, with a mixture of sunshine and heavy showers. However, the weather will quieten down later this week, as a ridge of high pressure builds in from the west.

Don’t forget, you can get the latest forecast on the Channel 4 Weather website. I’ll also be posting regular updates on Twitter – @liamdutton

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