Subtropical Storm Ana Threat Assessment for northeast South Carolina & southeast North Carolina Created 745 AM Fri May 8, 2015 Reid Hawkins, Science Officer National Weather Service Wilmington, NC 1
New Information Subtropical Storm Ana was named at 11 PM Thursday and is drifting approximately 160 miles south-southeast of Myrtle beach. The latest forecast track has the storm beginning to move to the northwest on Saturday and coming ashore along the South Carolina coast on Saturday. Some slight strengthening is possible through Sunday. Water levels at this time are only expected to be 1 to 1.5 feet above ground level. Only minor ocean over wash and moderate beach erosion is expected especially at times of high tide. The Subtropical Storm Watch is in effect for Pender, New Hanover, Brunswick, Horry and Georgetown Counties and coastal waters north of Little River. Subtropical storm warning is in effect for the coastal waters from South Santee River north to Little River. 2
Expected Threats/Impacts Matrix Hazards Specific to southeast NC and northeast SC The primary impacts are still forecast to be marine, and flooding from rainfall. Other impacts are expected to be low, but minor surge, an isolated tornado, and gusty winds are all possible. **Refer to Threats/Impacts Summary slides for more detailed information** 3
Wind Threats/Impacts - Summary Subtropical storm Ana will bring winds near tropical force by Saturday Afternoon with winds 30 to 40 mph and gust to around 45 mph along the coastal counties mainly south of Little River, SC. Winds for Myrtle Beach (likely the highest in our forecast area) shows northeasterly winds increasing Saturday afternoon into Sunday. Power Outages Isolated power outages possible, especially near the coast mainly south of Wrightsville Beach. Tree Damage Some small limbs may be blown down. 4
Potential Rainfall Amounts o The heaviest rainfall is expected along the immediate coast from New Hanover County southward. o Storm Total rainfall amount of 1 to 3 inches are possible generally from Hampstead, NC southward. o This system is expected to have a sharp cut-off in rainfall farther to the west thus rainfall amounts farther inland into the Pee Dee and Lumberton areas is expected to be less than ½ inch. 5
Marine, Surf, and Aviation Threats/Impacts Winds/Seas Across the Coastal Waters (0 to 20 nm) winds will increase to 30 to 35 knots with higher gusts through Saturday Night especially south of Cape Fear. Seas will build in excess of 10 ft. Conditions farther offshore, especially in the vicinity of the Gulf Stream will be much worse. Inlet entrances are expected to become hazardous as well, especially during the falling tide. The large incoming waves and currents in the inlet will generate large/steep waves. Rip Currents & Surf Strong rip currents...large breaking waves...and strong longshore currents will create dangerous surf conditions at all local beaches. MVFR Ceiling are expected through the storm and IFR visibilities are possible during strong squalls as the rain bands cross the airfields. Strong NE to E winds will impact operations Friday into Sunday. 6
Current Watches and Warnings 7
Storm Information Advisory #2 5 AM EDT May 8 Position: 31.6 North 77.8 West, 160 miles south-southeast of Myrtle Beach or 180 miles south of Wilmington. Intensity: Sustained winds are near 45 mph (Subtropical Storm). Some slight strengthening is possible over the next day or so. Movement: Ana is drifting with a turn to the northwest expected in the next 48 hours. Minimum Pressure: 1004 mb or 29.65 inches. 8
Official Track Information The latest track continues to meander the storm off the coast and then make a slow move to the northwest on Saturday toward the South Carolina coast. The storm first tropical force winds are expected late morning Saturday NHC Advisory # 2 5 AM EDT Fri May 8, 2015 *Note: This graphic does not represent an impact swath, and also note that statistically, one third of the time the storm can be outside the 5 day error cone. 9
Additional Information Available at: Facebook: US National Weather Service Wilmington NC Twitter: @NWSWilmingtonNC Web: http://weather.gov/ilm National Weather Service Wilmington, NC 10