Ana Transitions to a Tropical Storm

As Subtropical Storm Ana sat over the relatively warm Sea Surface Temperatures of the Gulf Stream, it drew energy from the upper ocean.  More thunderstorms developed near the center of circulation and condensation released latent energy which warmed the middle and upper levels.  As a result, the circulation became more circularly symmetrical and eventually some upper level outflow developed at the top of the system. As a result of the structural changes, Ana made a transition from a subtropical storm to a tropical storm.

At 11:00 a.m. EDT on Saturday the center of Tropical Storm Ana was located at latitude 32.7°N and longitude 77.9°W which put it about 90 miles southeast of Myrtle Beach, South Carolina and about 105 miles south of Wilmington, North Carolina.  Ana was moving toward the northwest at 3 m.p.h.  The maximum sustained wind speed was 60 m.p.h. and there were gusts to 70 m.p.h.  The minimum surface pressure was 1001 mb.

A Tropical Storm Warning remains in effect from South Santee River, South Carolina to Cape Lookout, North Carolina.  A Tropical Storm Watch is in effect from Edisto Beach to South Santee River, South Carolina.

As the high pressure system that has been blocking the forward progress of Ana moves eastward, the tropical storm will move toward the coast.  It is likely to make landfall near the border of South Carolina and North Carolina on Sunday morning.  An upper level trough approaching from the west will turn Ana toward the northeast and sweep it out to sea after it makes landfall.

Ana is still over the relatively warm water of the Gulf Stream and it is likely to maintain its intensity on Saturday.  When Ana moves north of the Gulf Stream, it will cross over cooler water.  In addition, the approaching upper level trough will begin to generate some vertical wind shear over Ana.  The effects of cooler water and more wind shear mean that Ana will likely be weakening as it approaches the coast.  It will bring some wind, locally heavy rain and beach erosion, but the impacts should be minor in most locations.