Update, Wednesday evening (9 p.m.): A mandatory evacuation has been ordered for Hatteras Island, North Carolina beginning 5 a.m. Thursday due to the potential for coastal flooding as the storm approaches shore and potentially makes landfall late Thursday night into Friday.

Arthur showing off a developing eye around 4:00 p.m. this afternoon. (NASA)

From 5:30 p.m.: As of the 5 p.m. National Hurricane Center update, Tropical Storm Arthur had sustained winds of 70 mph – just 4 mph shy of hurricane intensity. The storm has become better organized throughout today. It is likely that Arthur will become a hurricane at some point in the not-too-distant future, and hurricane warnings are now up for coastal North Carolina. Tropical storm warnings have been issued for extreme southeast Virginia.

Conditions should begin to deteriorate along the Outer Banks Thursday afternoon, with increasing winds and the initiation of heavy rain bands. Tropical storm to hurricane force winds are possible overnight. Coastal flooding is likely, with a storm surge of 2-4 feet predicted.

There remains strong consensus that Arthur will make its closet pass to the Outer Banks of North Carolina early on Independence Day (a 4th of July storm is quite unusual based on the historical record!). Today’s European model showed a very strong storm impacting that area around 8 a.m. on Friday:

Check out CWG’s Jason Samenow’s latest thoughts on Arthur:

Tropical storm Arthur looks likely to become the first hurricane of the season as it visits the East Coast between now and the July 4 holiday weekend. The Post's Jason Samenow gives an updated forecast. (Tom LeGro and Jason Samenow/The Washington Post)

For detailed information on what to expect at different locations up and down the East Coast, see our earlier blog post: Tropical storm Arthur nears hurricane intensity: a guide to coastal impacts around July 4 holiday