Threat Assessment for northeast South Carolina & southeast North Carolina

Created 6 AM Wed July 3, 2014

National Weather Service Wilmington, NC

1

Hurricane Arthur

Reid Hawkins

donald.hawkins@noaa.gov

New Information

2

Arthur was upgraded to a Hurricane with sustained winds of 75 mph on the 5 AM

advisory. The Warning and Watches for the area have not changed.

The track and speed of the storm is very similar to the previous advisory.

Hurricane Arthur is moving north and is expected to turn to the northeast and

parallel the Carolina coast today through Friday morning.

The first tropical force winds are expected along the coastal counties by mid

to late afternoon and will continue until Friday evening in northeast South

Carolina and after midnight in southeast North Carolina.

With the new update there are no changes to the coastal inundation areas

along the marshes and next to low-lying tidal creek areas. Inundation less

than 3 feet (most of the marsh areas show up to 3 feet inundation).

Expected Threats/Impacts Matrix

3

**Refer to Threats/Impacts Summary slides for more detailed information**

Hazards Specific to southeast NC and northeast SC

-Hazardous

boating, especially

Cape Fear area

waters north

-Moderate risk

mainly for

coastal Cape

Fear Area

Wind Threats/Impacts - Summary

Hurricane Arthur will graze the Cape Fear coast and fortunately the strongest winds will remain over

the adjacent Atlantic Waters. Winds will begin to increase across the Cape Fear area and coastal

northeast South Carolina Thursday morning, peaking Thursday evening.

4

Power Outages – Widely scattered outages possible, especially across the Cape Fear coastal areas

(long term outages not expected).

Structures – Minor to locally moderate damage is possible along the coast to unanchored mobile

homes, poorly supported porches, awnings, etc. Secure any loose items around the house (lawn

furniture, canopies, tents etc.)

Tree Damage – Some large limbs, shallow rooted trees, and diseased trees may blow down with the higher

winds.

Bridges/Overpasses – Travel may become difficult across coastal bridges, especially in the Cape Fear area

by Thursday afternoon and evening.

Bald Head Island Winds (likely the highest in our forecast area) shows easterly winds increase early Thursday afternoon,

then peak from a northerly direction Thursday evening as the storm is at its closest approach to our area.

Wind Threats/Impacts – Peak Sustained Wind (MPH) Swath

5

**Based on current track/intensity the expected peak sustained wind at the height of the storm**

o Highest winds are expected to impact

southeast coastal portions of

Brunswick County as well as coastal

portions of Pender and New Hanover

o Winds will begin to increase Thursday

afternoon and peak Thursday night as

the storm is at it’s closest approach.

o Gusts to 50 to 66 mph are possible

along the Cape Fear coast on

Thursday evening and night.

o Fortunately, the strongest swath of

winds will remain off the coast as the

storm moves by.

o Please note: Any additional subtle

westward shift in the track could bring

stronger winds toward the coast,

while an eastward shift would mean

less wind.

Coastal Flood Threats/Impacts Graphics

6

- Coastal inundation up to 3 ft is possible, especially

along the marsh areas, beaches, and other vulnerable

low-lying tidal areas. Some structures in vulnerable

coastal flood locations may be at risk.

- Beach erosion is likely with the surf zone reaching the

dunes. Large waves and currents will make the ocean

dangerous Thursday through Friday morning.

Refer to the coastal inundation graphics at

the Natl. Hurricane Center’s webpage for

details in your area.

Potential Rainfall Amounts

o The bulk of the rainfall will remain off

the coast. However, rainfall chances

will increase along the coast by

Thursday morning/afternoon and peak

during the evening.

7

o Storm Total rainfall amount of 1 to 2

inches is possible along the coast with

the higher totals near Holden Beach,

Southport, and Carolina Beach.

o Any further westward shift in the

forecast track could add to the rainfall

totals, while a shift to the east would

mean less rain for our area.

o Lesser amounts are expected inland

as there will be a tight gradient to the

rainfall.

Marine and Surf Threats/Impacts

Winds/Seas – Across the Coastal Waters (0 to 20 nm) winds will increase to 40 to 50 knots

with higher gusts Thursday through Thursday evening with gusts in excess of 80 kts Little

River Inlet north to Surf City and around 60 kts south of Little River Inlet. Seas will build in

excess of 15-18 ft. Conditions farther offshore, especially in the vicinity of the Gulf Stream will

be much worse with seas approaching 30+ ft.

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.

8

Surf – Large/powerful breakers are expected in the surf zone, increasing Thursday and

persisting into Friday morning. Swimming is not advised due to the rough surf and potential for

strong currents.

Rip Currents – The threat of dangerous and life threatening rip currents will increase through

Thursday, and will persist through all of Friday in the wake of the storm.

Aviation Threats/Impacts

Scope of Aviation Impacts – Mainly an impact for coastal terminals in

southeastern NC with minor to moderate impacts at KCRE and KMYR.

KILM will have the greatest impact in our forecast area with wind gusts

approaching 50 kts late in the afternoon/early evening

9

Timing of MVFR/IFR – MVFR conditions developing Thursday morning and

persisting into early Friday morning. Temporary IFR conditions with any rain

bands Thursday afternoon, and especially during Thursday evening.

Conditions expected to improve after daybreak Friday morning.

10

Current Watches and Warnings

Position: 31.3 North 79.1 West, 220 miles south-southwest of

Wilmington.

Intensity: Sustained winds are near 75 mph (Hurricane). Additional

strengthening is possible as Arthur move past our area and towards the

Cape Hatteras.

Movement: Arthur is moving to the north at 9 mph. A turn towards the

northeast is expected today and an increase in forward speed Thursday

night.

Minimum Pressure: 985 mb or 29.09 inches.

11

Storm Information – Advisory #10 500 AM EDT Jul 3, 2014

Official Track Information

The latest track continues to

move the storm parallel to the

Southeast United States coast.

12

Track is similar to the last

advisory.

*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.

The storm will be at its closest

approach to the Cape Fear area

Thursday evening

Fortunately the front right

quadrant will remain off the

southeast NC and northeast SC

coast lessening the storm surge

impacts.

Next Briefing Information

Next PowerPoint available:

13

Next conference call time:

1 PM EDT today

130 PM EDT today

14

National Weather Service Wilmington, NC

Facebook: US National Weather Service Wilmington NC

Additional Information Available at:

Twitter: @NWSWilmingtonNC

Web: http://weather.gov/ilm