The Met Office has issued an amber warning for rain and yellow warning for wind for today (February 16), hot on the heels of Storm Ciara.
It has warned more than 100mm of rain could fall on already saturated ground in some locations and winds could reach up to 60mph in exposed areas.
We have been told to expect travel disruption, flooding and damage to property. Dozens of flights have already been cancelled from Gatwick Airport.But how are things looking for the next few hours?
The rain has been constant all day and is not forecast to let up until well into the evening. Residents are seeing around 4mm of rain per hour as of 3pm this afternoon, but that is set to ramp up at around 5pm.
From around 5pm, another heavy downpour of up to 16mm per hour is set to fall as Dennis continues to move east.
The good news is, that is forecast to be the worst of it and rain is expected to gradually subside into tonight.
Storm Dennis' amber warning means upwards of 32mm of rain could fall per hour.
The Met Office recently upgraded its warning, with rainfall now predicted to measture around 60mm per hour in some places, landing on already saturated ground.
Wind gusts of up to 50mph are also forecast into the evening and beginning of next week.
Here is what to expect:
Homes and businesses are likely to be flooded, causing damage to some buildings
Fast flowing or deep floodwater is likely, causing danger to life
Delays and some cancellations to train and bus services are likely
Spray and flooding probably leading to difficult driving conditions and some road closures
A good chance some communities cut off by flooded roads
Power cuts and loss of other services to some homes and businesses likely
The wet weather will be joined by average wind speeds of around 30mph, with stronger gusts nearer to the coast.
We'll bring you ongoing weather updates as the weekend progresses, so keep an eye on this page.
For safety and travel advice, read this: Storm Dennis set to hit Sussex this weekend – here’s all you need to know