- Thunderstorms, lightning and hail predicted for parts of Britain
- Snow forecast across Midlands, North and Scotland this week
- Another two weeks of wet weather for the rest of the country
Unsettled: Forecasters say there is a chance of funnel clouds forming over the next few days which can turn into tornadoes when they touch the ground, like this one in Coventry in 2005
Much-needed rain is set to fall across the whole country today, but could develop into thunderstorms, lightning and hail in some parts.
Cold winds passing over hot air rising from the ground is causing the unsettled weather that is going to last until after the weekend.
Snow has returned to County Durham and forecasts predict many northern areas of the UK will have more from today
George Goodfellow, a Met Office forecaster, said: 'The rain could get quite heavy and thundery on Thursday and Friday with the chance of funnel clouds.
'It is not going to be a complete wash-out, but the showers look likely to be particularly widespread and cannot be ruled out in any part of the country.'
Funnel clouds are violent rotating columns of air formed when warm and cool airstreams collide - and can become tornadoes when they touch the ground.
Forecasters would not predict whether this might happen.
Temperatures are set to reach around 13c (55F), which is typical for this time of year, with a low just about freezing at night.
Around 50mm of rain is forecast to fall by Sunday, which is the same as the total rainfall expected for the whole month.
But forecasters warned that much more rain would be needed to relieve the drought in the South and East.
Weather experts said that areas affected by drought need more than 400mm of rain to get back to normal levels.
In Scotland, ski resorts have been told that they may be able to reopen thanks to a chance of snowfall.
It's all a stark contrast to last April - which was the hottest since 1910, with temperatures regularly topping 25 degrees - and comes just weeks after a March heatwave that sent scores of Brits to the beach.
What a difference a week makes: Charlotte Robertson plays in the snow in a park in Aboyne, Scotland on April 4, 2012. Just a week before she was pictured in the same park when the temperature was 26 degrees warmer
The Environment Agency yesterday warned that the drought conditions gripping swathes of England could increase the risk of flash flooding.
Dry, compacted soils mean that rainfall is less easily absorbed into the ground, increasing the likelihood of flooding if the country is hit by storms.
The Environment Agency said a dry winter and spring in 2007 contributed in some areas to the devastating floods in the summer of that year, which hit the West Country, Midlands and Yorkshire.
Parts of the country had similar conditions as those currently seen in drought-afflicted areas, before the heavy rain hit in June and July 2007.
Cars abandoned in snow drifts in Saddleworth Moor, Oldham in Greater Manchester last month
Steady rain is forecast in the Liverpool area over the next few days and conditions on the course are expected to be the muddiest and most difficult since the famous mudbath of 2001, when Richard Guest splashed to victory riding Red Marauder.
Clerk of the course Andrew Tulloch expects the ground to be 'soft' - but expects the race to go ahead, regardless how muddy it gets.
He said: 'We've had at least 13mm of steady drizzle and, looking at the radar, there should be more to come on Tuesday with further possible showers on Wednesday and Thursday.'
'The grass is in excellent condition, partly as a result of the warm winter we had, and that makes a difference, as it will help soak up a lot of the moisture,' he told the Guardian.
'But the going is already soft in most places on the National course and we're definitely looking at conditions being on the slow side. We've been aiming to get something between good and good to soft.'
And things are set to get worse. The Environment Agency warns we could soon find ourselves paying the price for the dry start to 2012.
Dought afficted areas, like much of southern of England, are at higher risk of flash flooding - as witnessed in 2007, when a dry winter and spring was followed by devastating floods.
Craig Woolhouse, Environment Agency head of flood incident management, explained: 'As the drought in England continues, the thought of flooding may be far from people's minds, but we cannot ignore the risk.
'Dry and compacted ground means that there is a greater risk of flash flooding if there is heavy rainfall, and stormy seas and high tides can produce floods at any time.
'Being prepared is vital to help reduce the risk of flooding.'
Meanwhile, the sudden cold snap has left a pair of hairless 'skinny pigs' shivering.
Rio (left) and Salvador, a breed of bald guinea pigs who are so sensitive to the elements that they usually need factor 50 sun cream to go outside
But this week they have spent their days huddled under hand-knitted woolly blankets instead.
The pair of cute critters were born at Whitehouse Farm Centre in Morpeth, Northumberland this January and have already proved a hit with visitors.
The skinny pigs are born with no hair and only grow small tufts on their head, face and feet.
Heather Hogarty, who cares for all small animals at the centre, said: 'Their skin is so sensitive we have to put on factor 50 if they go out in the sun, they'll burn up otherwise.
'We just use normal, fragrance free, sun cream that humans would use.
They have to be moisturised with special aloe vera gel every week though.
'Salvador and Rio love it, they love being pampered. When it got cold though you could see them huddled together trying to keep warm.'
We should be seeing big spots. Really big spots.
A cursory examination of spots at solarham.com reveals tiny motes that are better described as 'blinkers'. If you blink, you'll miss them.