National Weather Service Wilmington, NC
We use NWS Wilmington information because it includes northeastern South Carolina– which includes North Myrtle Beach)

— Potential for Coastal Flooding Increasing Each High Tide Sunday into Tuesday

— Ocean water piling up to and into low areas around the dunes is expected to develop. In addition, coastal flooding of other vulnerable low-lying areas along the coast is likely as the wind strengthens between the area of high pressure to the north and the peripheral circulation of Hurricane Irma.

— The onshore wind that develops and increases Sunday, and especially Monday, will result in coastal flooding with inundation of 2-feet to 3-feet possible. Impacts will be greatest around times of high tide Sunday and peaking Monday/Monday night, possibly persisting into Tuesday.
— Elevated water levels and large breaking waves in the surf will cause significant wave run-up and erosion along all area beaches. Inundation is especially likely in those coastal areas made vulnerable by Hurricane Matthews surge. Areas around some of the tidal creeks and bays may experience some inundation as well.
— Northeasterly winds Sunday will turn nearly directly onshore Monday as Irma moves northward across Florida creating a fetch which will drive water toward the Carolina coastline and cause coastal flooding
— Sunday late morning: Minor over-wash, Sunday late evening: Minor over-wash
— Monday noon: Coastal flooding likely,
— Tuesday midnight: Coastal flooding likely
— Tuesday noon: Coastal flooding possible
— Wed midnight: Minor over-wash possible