They also warned roads could be affected by freezing rain overnight.
A number of airports have also taken the precaution of cancelling a number of flights - so there's no escape from the disgusting weather.
"There is an increasing chance that a further spell of more persistent snow may move north into parts of southern England, Wales and central England during the day".
Scotland: Glasgow Airport is closed until at least 3pm local time (10am E.T.) because of heavy snow showers overnight. An earlier red warning in place for much of Scotland was downgraded to amber on Thursday morning.
Major incidents have also been declared in Avon and Somerset, Hampshire, and Wiltshire, as Storm Emma abtters the United Kingdom with strong winds and snow.
Parts of the United Kingdom are braced for up to 50cm of snow, as Storm Emma brings worsening conditions.
Gatwick Airport: About 50 of the 350 flights due to depart from the terminal have been cancelled and there are also significant delays to other flights.
The national weather forecaster predicts blizzard conditions tonight and during Friday in Leinster and Munster.
The National Grid issued a "gas deficit warning" prompting fears of a shortage, but households were reassured domestic supplies would not be affected.
Meanwhile, a Level 3 cold weather alert is in force for all of England for the coming days.
"That big mass of Arctic air - which is normally trapped over the poles, so it's really freezing cold - is then able to spill further south", Clark told CNN.
The hotel brand, which represents over 250 independently owned and managed properties, estimates that cancellations in the last 48 hours have cost its member properties almost £90,000 in lost bookings revenue and that the overall cost of the weather to the United Kingdom hotel industry could be in excess of £4million for the last two days - a figure that is expected to increase as the weather continues to impact areas this weekend.
The Red Warnings mean there is a danger to life and pontential for signifcant travel disruption, so must be taken seriously by everyone, they are a trigger for emergency services and authorities to take immediate action and for the general public not to travel unless in an emergency. This is so that we can get as many of you home as possible. "It's changing faster than we can collect data on it", Clark said.