Matt Taylor
BBC Weather

A number of factors are in play, which include the weather set-up, the direction of the wind, and the geography of the area.

WEATHER SET-UP

With a big stubborn area of high pressure sitting across Scandivania right now, any weather systems coming in of the Atlantic are getting stuck with no place to go. This has meant a rain-bearing weather front that swept north across the UK last night has ground to a halt in the area, meaning persistent rain.

The weather system also started out over the warmer climes of the mid-Atlantic. The warmer air feeding it is full of moisture, leading to greater rainfall potential.

WINDS

The direction of the wind is crucial. The UK’s prevailing wind direction is off the Atlantic, meaning western areas usually receive the highest rainfall totals. This time we unusually have a prolonged spell of strong east to south-easterly winds. This results is eastern areas naturally seeing the highest rainfall totals.

GEOGRAPHY

As those winds meet the high ground of the Grampians, they are forced to quickly rise up to get over them. This causes something called “orographic enhancement”. With air rapidly rising and cooling into deeper clouds on the eastern side of the mountains, it leads to higher rainfall totals. Stronger winds enhance this even more.

This then rapidly flows down into the low-lying areas across south Aberdeenshire, Angus and Perth & Kinross, resulting in the extensive flooding warned of in the Met Office red weather warning.

Image source, PA Media

Brechin is at the centre of Storm Babet as it faces major flood threats.

Residents will be evacuated over fears the river's flood defences could be breached.

The town, which is about 27 miles north east of Dundee, is currently covered by a red weather warning for rainfall.

Brechin sits alongside the river South Esk, in the north east corner of lowland Angus.

The town has previously flooded and a £16m flood prevention scheme was completed in 2015 to prevent further floods.

There are just over 7,000 residents who live in the town.

Emergency rest centres are being set up for residents and hotels for the most vulnerable.

Storm Babet could cause landslides across Scotland, the British Geological Survey warns.

A spokesperson for the group said there's a history of coastal landslides in the areas under warnings, and that "infrastructure slopes are also likely to be affected with potential for disruption to roads and railway within the warning area.”

Less than two weeks ago, seven landslides occurred in Argyll and Bute causing 9,500 tonnes of debris to fall onto the roads.

Image source, SSEN

SSEN says Storm Babet is already causing problems in the electricity network.

The power company has already restored power to 7,000 homes and is working to reconnect about 3,000 more.

Extra staff have been deployed ahead of the worst of the weather.

The company's real-time map of affected areas showed an increase from under 40 power outages at 11:00 this morning to more than 80 at about 14:00.

You can see where the power is out on the live Powertrack map here, external.

SSEN is warning people not to touch any damaged equipment, but to call them on 105 instead.

A severe flood warning has been issued for Brechin in Angus.

Twelve flood alerts and seven warnings are in place for other parts of Scotland as Storm Babet sweeps across the country.

Flood alerts are still in place from Aberdeen to Dundee and Angus, while a flood warning for Dumfries and Galloway is no longer in force, Scotland's Environment Protection Agency (Sepa) said in its latest update.

The heaviest and most prolonged rainfall is expected to hit Aberdeen City, Dundee and Angus, Tayside, Aberdeenshire and Caithness and Sutherland.

This KLM passenger plane performed a 'go-around' after aborting its landing at Aberdeen Airport.

The rain in Brechin has been coming down heavily and steadily for last few hours and the town's river is already getting very high.

Christopher McGuire is among the many residents in the town doing what they can to safeguard their houses.

He told the BBC’s Reporting Scotland programme how his back garden flooded with three feet of water just two weeks ago.

He now fears the water could come over his back wall and is preparing for the worst of the flooding.

“If it’s up river and comes down to the catchment area, that’s the problem,” he said.

“We’ve got plenty of ground still fairly wet from two weeks ago and I think it’ll come over.”

Jamie McIvor
BBC Scotland News Correspondent

ScotRail is urging passengers planning to travel later today to check for cancellations and delays.

Rail services in parts of the country covered by the red weather warning have already been cancelled.

Some disruption in other parts of the country is possible.

The company hopes to give some information this afternoon about cancellations tomorrow.

Image source, Gillian Lee Mitchell

Gillian Lee Mitchell took this picture of a fallen tree across her driveway in Downfield, Dundee.

It has left both her and her neighbour blocked in.

Dundee has just been added to the area covered by the Met Office's red weather warning.

Image source, Nick Archibald.

And another fallen tree on Balbithan Road (B977) near to the Kintore turn-off, taken by Nick Archibald.

If you’re just joining us, here are the main developments as Storm Babet lashes the UK:

• Hundreds of homes in the town of Brechin in north east Scotland are being evacuated amid fears that flood defences will be breached
• A red severe weather alert – which warns of risk to life - has extended to more areas of Scotland including Perth and Kinross, Dundee, Angus and south Aberdeenshire
• Travel has been severely hit with police advising not to travel in the red alert area and to avoid it in the amber areas. The Forth Road Bridge has been closed, trains cancelled across Scotland, and more than half of CalMac’s ferry routes cancelled
• Schools and businesses have been closed, sandbags laid and floodgates closed as people try to get ready for the main impact of the storm from 18:00
• Powerlines are a particular concern although – so far – disruption to supply appears to be limited
• The impact of the storm has been felt right across the UK with storm damange being felt from Devon to Newcastle

Angus Council has confirmed that 350 homes have been told to evacuate in Brechin.

The properties affected are in the River South Esk area and further north.

Rest centres will be open from 15:00 this afternoon for residents at Montrose Sports Centre, and Brechin and Forfar community campuses.

People are being asked to bring their own sleeping bags and any supplies and medications they will need.

The council is expected to provide another update at 16:00.

Louise Cowie
BBC Scotland reporter in Arbroath

Here in Arbroath, local people are bracing themselves for the full force of Storm Babet.

This town is right in the centre of the red warning area which is expected to see the worst of the conditions later today.

But at the harbour area, the roads are already closed off as the waves come crashing in and the strength of the wind is making it hard to stand. High tide is still to come.

In the town's main street, one building has seen part of its roof lifted off and bins are strewn around the streets. Locals are trying their best to stay safe in difficult conditions.

Matt Taylor
BBC Weather

The Met Office red warning area has recently been extended in areas to cover parts of Perth & Kinross, but we still expect to see impacts across other parts of the UK.

SCOTLAND

Flooding impacts from heavy rain are also expected in various Met Office amber weather warnings through today and tomorrow more widely across eastern Scotland and parts of the north Highlands.

There also remains and amber warning for strong winds in eastern areas of Aberdeenshire and Angus.

ENGLAND

Amber warnings have now been issued along the eastern Pennines, Peak District, parts of Greater Manchester and Cheshire. Persistent rain through Friday and Friday night may have flooding impacts and swell rivers in these areas.

A wider yellow warning, indicating a lower possibility of flooding is also in force more widely across northern England, the north Midlands and East Anglia.

NORTHERN IRELAND and WALES

All of Northern Ireland and north Wales are also covered by the lesser yellow warnings for rain tomorrow, and tomorrow night, but we should be alert to the potential for flooding in these areas too.

Angus Cochrane
BBC Scotland News

As we reported earlier, Sepa flood unit manager Pascal Lardet has raised fears of flooding in eastern Scotland.

He's been speaking to reporters this morning, and said he's worried flooding "will happen overnight".

“We will try to anticipate as much as we can," he added. “There’s a specific focus in the Brechin area which has flooded in the past.”

The Angus town's flood defences were tested a year ago, he said, but the predicted rainfall this time will be “even greater”.

He said Sepa was forecasting the water level will “be close to the top of the [flood] defence” and there was a significant risk because water going over the top of the defences could lead to a “rapid inundation” to surrounding areas.

Angus Cochrane
BBC Scotland News

More on Sepa saying evacuations could be ordered in Brechin amid fears its flood defences could be breached...

The area is covered by a red weather warning for rainfall, stating there is a risk to life.

Sepa spokesperson Pascal Lardet said forecasts had suggested flooding would bring water to the limit of local flood defences in Brechin.

He said a decision would be made on Thursday afternoon on whether an evacuation would be ordered.

The responsibility for ordering an evacuation would lie with Police Scotland, he added.

Residents of Brechin may need to be evacuated if the Angus town's flood defences are at risk of being breached, Scotland's Environmental Protection Agency (Sepa) says.

The coastal north east of Scotland is set to see some of the most extreme weather tonight and tomorrow - and it's not exactly flat calm at the moment.

The crashing waves at Peterhead harbour in Aberdeenshire offer an ominous glimpse of what could be to come.

The Met Office's red warning for heavy rain has been extended to cover a wider area.

The updated warning, external now reaches Perth and Dundee and some surrounding areas, after initially covering parts of Aberdeenshire and Angus.

Met Office updated warnings are:

Red

• Rain 18:00 Thursday - 12:00 Friday. Angus, south Aberdeenshire, Dundee, Perth and Kinross.100 to 150mm of rain is expected to fall widely, locally 200-250 mm of rain

Amber

• Rain - Eastern Scotland 06:00 Thursday - 1800 Friday
• Rain - Sutherland and Caithness 18:00 Thursday - 0900 Friday
• Rain - South-east Scotland 12:00 Friday - 0600 Saturday
• Wind - North-east Scotland 10:00 Thursday - 1800 Thursday

Yellow

• Rain - North and east Scotland 06:00 Thursday - 23:59 Saturday
• Wind - Sutherland and Caithness 03:00 Thursday - 1200 Friday
• Wind - East coasts 12:00 Friday - 1200 Saturday

Image source, PA Media

Flood barriers are being erected around the country, including in Edzell in Angus, as we head closer to the Met Office's red weather warning for heavy rain coming into force at 18:00.

Flood barriers on Queen's Bridge, Perth are now in place and the road is closed.

Parts of Angus and Aberdeenshire have been told to expect the extreme weather to last until noon on Friday.

Storm Babet is forecast to bring extensive flooding to Scotland's north-east coast.

The Met Office has just issued a new amber weather warning for rain in northern England, the Midlands and Wales.

It will be in place from midday tomorrow until 06:00 BST on Saturday.

It's likely there will be flooding, they added, as they anticipate between 40-60mm of rainfall.