Thursday, August 27, 2009

Tropical Storm Danny Update

Danny has weakened further this evening, with maximum sustained winds of only 45 mph. A tropical storm watch was issued this afternoon for much of the OBX from Duck to Cape Lookout. While some strengthening is possible over the next 36 hours, it does not appear very likely for Danny to achieve hurricane strength. I expect the center of Danny to move approximately 75 miles east of Cape Hatteras early Saturday morning. Tropical storm force winds will likely extend outward roughly 100 miles from the center of the storm, resulting in a brief period (3-4 hours) of winds in the range of 30-45 mph on the Outer Banks. I don’t think the storm will be large enough to spread a disruptive measure of wind and/or rain into central Virginia.

Danny Update: Lopsided Storm

Tropical Storm Danny's intensity remains the same mid-day Thursday, with maximum sustained winds at 60 mph. The organization of the convection is slightly better, but there is still no visible eye or symmetry to the storm, as one would expect from a "classic tropical cyclone." In fact, you could maybe tease Danny about being "naked" because the center of rotation at the surface is what we term "exposed." I.E., the convection is all shifted to the right of this surface low pressure center, and there aren't storms rotating around the entire "eye." Check out the visible image:

Weird, isn't it? This might be a result of the upper-level flow keeping some shear in the vicinity of Danny.

Here's the latest computer guidance for the track of Danny. The Tropical Storm is still expected to intensify to a Category One hurricane before transitioning to an extra-tropical cyclone later this weekend. Danny should pass just to the east of the NC and VA coastlines, bringing rough surf and steady winds of 15-30mph Saturday.





Drought Update: Past Week's Rains Help!


Early last week, more than half of the state was in abnormally dry conditions, teetering on the edge of a drought unless a fresh infusion of rain came soon. Sure enough, we had several rounds of heavy rains that moved through much of Central Virginia over the past week, including last Saturday's line of strong thunderstorms (up to 5" in spots!) that stretched clear from D.C. to the North Carolina border, and also late Sunday into early Monday's swath of strong to severe storms that swept through and dumped 1"-3" of much-needed rain. In light of these events, the abnormally dry conditions were lifted from nearly all of the state. Only parts of south-central Virginia along the North Carolina border, which has missed out on the heaviest of the rains, still remains "abnormally dry" in this week's Drought Update.

Tropical Storm Danny: Thursday Morning Update


Tropical Storm Danny has strengthened some overnight, with maximum sustained winds now at 60mph. However, Danny isn't showing a classic tropical cyclone "look." There is still no eye, and the convection is not symmetric around the center of rotation (see enhanced IR satellite image above). The latest track estimates do keep Danny just offshore this weekend, before it accelerates along the New England coastline as a Category One storm and transitions to an extratropical cylone (IE, it loses its tropical characteristics).