Sussex Police said enquiries were continuing into the disappearance of Richard John Wise.
Last week police said they were growing increasingly concerned for the welfare of the 77-year-old man who went missing from his home in Chichester Road, Seaford,just after Christmas.
Mr Wise was last seen at home at 3pm on Sunday December 29 and is thought to have disappeared between then and about 8pm.
In the meantime, the Sussex coast has been lashed by gale force winds and heavy rain.
Mr Wise is known to be without food, drink or his regular medication.
Sussex Police described him as white, 6ft 2in, with grey/brown short hair.
He is believed to be wearing a blue anorak, light-coloured trousers and brown lace-up shoes.
Several possible sightings of Mr Wise have each drawn a blank.
An extensive search of the local area involving more than 50 police officers and civilian volunteers has proved equally fruitless so far.
Inspector Stephen Tullett of Sussex Police, said every effort was being made to try to find Mr Wise, spurred on by the knowledge that he was ill-prepared for the weather and was clearly vulnerable in other respects.
Police renewed their appeal to the public to keep their eyes open and to contact police without delay if they have any information about Mr Wise’s whereabouts.
Anyone able to help should phone Sussex Police on the non emergency number 101.
Or you can email: firstname.lastname@example.org
Quote Operation Eddington.