Tuesday Afternoon Update- Tropical Storm Arthur

Well since my last blog post the disturbance off the southeast coast has strengthened and is now classified as Tropical Storm Arthur! This is our first named storm of the 2014 Atlantic Hurricane Season. Arthur still seems to be on track to impact Eastern VA and especially Eastern NC as we approach July 4th with some rain, wind and coastal flooding.

To strengthen, hurricanes need several things. First, they need little wind shear to allow t-storms to form over the center. They also need warm sea surface temperatures and moist air. To get a very strong storm, typically you’d want to see some good symmetry on the system too with storms around each side of the center or eye of the storm.

symmetryAt 2 pm Tuesday, the storm was off the coast of FL and becoming better organized. In the past few hours, we’ve noted a flare up of t-storms on the northern side of the system, which is what you want to see if you want the storm to strengthen. In the image to the right, I’ve outlined each quadrant and talked a little about the storm activity in it. For the past day, most of the storms associated with Arthur have been on the southern side so this flare up on the northern side is noteworthy.

Water Vapor TueIn terms of moisture, there is some dry air on the northern side of the system in the mid levels which I believe isn’t really allowing storms to fire up significantly on the northern side of the system. As we go through tonight and tomorrow though, we expect the storm to overcome this dry air and get better organized. So, with 2 out of 3 of the ingredients seeming to becomd more favorable, what about sea surface temperatures?

usatlant.cfWell… sea surface temperatures also seem to support a tropical system. Usually you want temperatures in the upper 70s to 80s to support tropical storm or hurricane strength storms. With the warm Gulf Stream waters near the storm, these temperatures won’t be an issue and we expect the storm to strengthen as atmospheric conditions become more favorable with the combination of these 3 features improving.

The National Hurricane Center’s current track expects Arthur to approach the Outer Banks as we go into Thursday night and Friday morning as a Category 1 hurricane. Note though that Hampton Roads and Eastern Carolina are still in the cone of uncertainty. A 25 mile jog to the west could significantly change the impacts to the Outer Banks and VA.

So what is the bottom line? Basically, we just need to watch it. Right now, the storm system does not seem overly significant for Hampton Roads and if storms do not fire on the western side and we don’t get good symmetry of the storm, rain and wind will be pretty tame across Eastern VA. Hatteras,NC seems to be in the path to take the brunt of the storm. If you’re traveling down there, be aware of conditions and know that water often covers NC-12 in spots during storms. Be prepared to even be stuck there if the road gets washed away or sand covered. NCDOT will do their best, but you can’t always beat Mother Nature.

Main Headlines:

- Rain and some wind possible Thursday night into Friday morning across Hampton Roads
– Biggest impacts with Tropical Storm strength winds across NC Outer Banks
– Dangerous surf conditions with rip currents and large waves
– Conditions improving Friday night across all areas
– Weekend perfect across the area! Don’t cancel plans.

What you should do:
– Stay Tuned…
– If traveling SE to the Outer Banks Thursday night or Friday, consider postponing until Friday afternoon