(BIVN) – The National Weather Service reports a High Surf Warning will be in effect starting at midnight Wednesday into Thursday, as a “significant, extra large” northwest swell arrives to the islands. 

Surf heights of 35 to 45 feet will be possible along along most north-facing shores, forecasters say. 20 to 25 foot surf heights are expected along west-facing shores.

“Coastal inundation along various northern and western exposures is expected during times of high tide Thursday and Friday evenings,” the National Weather Service said.v “Preparations should be made for the threat of coastal flooding as ocean water runs up onto beaches and potentially impacts coastal properties and roadways.”

From the National Weather Service discussion posted on Wednesday morning:

A significant, XL northwest (320 degree) swell will arrive late tonight and rapidly build down the island chain Thursday. This swell will lift surf to well above High Surf Warning levels along most north and west-facing shores. The passing of this swell within moderate to locally strong northeast winds will result in rough sea conditions and warrant an SCA for most local nearshore waters. A swell of this size will adversely impact coastal areas, especially during periods of high tide both Thursday and Friday evenings. Preparations should be made for the threat of coastal flooding as ocean water runs up and inundates beaches and potentially affects coastal properties and roadways. The northwest swell will slowly decline Friday and Saturday with a large, medium period north swell (350 degree) following on its heels Saturday and Sunday. This swell will maintain solid High Surf Advisory level surf along most northern exposures and keep seas at SCA heights. Surf along east-facing shores will experience a rapid increase this weekend due to a combination of rough, short period trade wind swell and large north swell. Seasonal small surf will occur along south shores.