Storm Diana sweeps across the county
Met Éireann says there is also a risk of coastal flooding due to high seas.
Road users are being urged to be vigilant for debris and spot flooding, while the ESB says it has a number of crews on standby to deal with any power outages.
Around 3,500 homes and businesses are without power in the south of the country.
The National Directorate Fire and Emergency Management has asked local authorities to activate their severe weather teams.
Motorists are asked to check local weather and traffic conditions and be aware of the conditions before setting out on a trip.
The RSA has the following advice for road users:
· Beware of objects being blown out onto the road. Expect the unexpected.
· Watch out for falling/fallen debris on the road and vehicles veering across the road
· Control of a vehicle may be affected by strong cross winds. High sided vehicles and motorcyclists are particularly vulnerable to strong winds
· Allow extra space between you and vulnerable road users such as cyclists and motorcyclists
· Drive with dipped headlights at all times
Advice to Pedestrians, Cyclists and motorcyclists;
· Be seen. Wear bright clothing with reflective armbands or a reflective belt.
· Take extra care when crossing the road or cycling in extremely windy conditions as a sudden gust of wind could blow you into the path of an oncoming vehicle.
For advice on using the road in severe weather, please see severe weather advice on the RSA website or check out the RSA Facebook and Twitter pages.