That's according to Littlehampton Harbour, which warned that flooding could last for two hours along Rope Walk and may affect local roads.
The harbourmaster said the tide at 1.15pm is 'higher than normal' due to Storm Barra, which brings Gale Force 8 Southerly winds.
"The weather increases tide table values by 0.4 m," the harbour statement read.
"The total forecast tide is 6.40 metres Chart Datum (3.35 mAOD) at Littlehampton.
"For two hours either side of high water, the tide will cause flooding to boatyards and the industrial areas along Littlehampton Rope Walk."
Littlehampton Harbour said water will be high up slipways and 'could be forced up through drains', causing flooding to roads.
The statement continued: "The early Wednesday morning tide, at 1.45am, is predicted to be 10cm lower, but will be accompanied by very large waves.
"We expect flood impacts could be similar.
"Strong winds and large waves will continue until Thursday.
"We continue to monitor the forecast. If you have it, please install flood protection two hours before high tide."
Have you read?: Storm Barra: Yellow weather warning for Sussex