Flood warnings are likely to be issued in the broads area and low lying parts of Norfolk and Suffolk.
Residents can be warned of floods by phone, fax or email
The Environment Agency said north west gales up to Force Eight, low pressure and high tides could bring severe flooding early on Friday morning.
"Especially at risk are the broads and the coast down to Lowestoft," said Paul Woodcock, the agency's director.
"Once the situation is more definite we will be issuing flood warnings if appropriate."
Emergency planners from the police, councils, the Environment Agency and fire and rescue services are meeting and will be issuing updates on the situation.
The situation could change during the day, but the agency hopes to have a more definite picture of expected tide levels by late Thursday afternoon and will issue warnings as necessary.
Mr Woodcock said: "We would like people to especially think about any vulnerable neighbours. Please consider how you could help them to prepare for flooding."
The Environment Agency said people living in the affected areas should call Floodline on 0845 988 1188 for the latest flood warnings in their area and tune into media broadcasts.