The Met Office issued the rare alert overnight and it came into force at 10am.
A red weather warning means there will be ‘dangerous’ weather.
It is an updated on the amber weather issues on Wednesday.
The Met Office says that it expects that ‘Gusts of 60-70 mph are likely widely, perhaps briefly 80 mph in a few places, mainly on English Channel coasts’.
There is a ‘danger to life’ during the storm, the Met Office has warned.
A ‘major incident’ has been issued for Portsmouth.
Residents are warned of potential for power cuts.
On the Met Office’s website, the updated warning reads: ‘Storm Eunice causing significant disruption and dangerous conditions due to extremely strong winds on Friday.
‘Flying debris resulting in danger to life.
‘Damage to buildings and homes, with roofs blown off and power lines brought down.
‘Roads, bridges and railway lines closed, with delays and cancellations to bus, train, ferry services and flights.
‘Power cuts affecting other services, such as mobile phone coverage.
‘Large waves and beach material being thrown onto coastal roads, sea fronts and homes.’
The Met Office continues: ‘Extremely strong west to southwesterly winds will develop mid morning on Friday, transferring eastwards across southern and southeast England through the middle of the day then slowly easing from the west during the afternoon.
‘Gusts of 60-70 mph are likely widely, perhaps briefly 80 mph in a few places, mainly on English Channel coasts.’