Tropical Depression 2 intensified into Tropical Storm Bonnie as it passed over the warm waters of the Gulf Stream on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Bonnie was located at latitude 31.1°N and longitude 79.4°W which put it about 120 miles (195 km) south-southeast of Charleston, South Carolina.  Bonnie was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1008 mb.  A Tropical Storm Warning remains in effect for the coast of South Carolina from the Savannah River to Little River Inlet.

Although the convection in Tropical Depression 2 dissipated when it passed over a region of slightly cooler Sea Surface Temperatures (SSTs) on Friday night, thunderstorms redeveloped and persisted when the system crossed the warmer SSTs in the Gulf Stream on Saturday.  Persistent thunderstorms produced enough increase in the wind speed to intensify Tropical Depression 2 into Tropical Storm Bonnie.

The circulation around Tropical Storm Bonnie is very asymmetrical.  Almost all of the thunderstorms are occurring in the northwestern quadrant of the storm and the strongest winds are being generated in that part of the circulation.  There are mainly thin bands of showers in the rest of the storm.  Winds to tropical storm force extend out about 60 miles (95 km) from the center in the northwest quadrant of Bonnie.

An upper level low over Florida and an upper level ridge over the western Atlantic Ocean are combining to generate southeasterly winds which are blowing over the top of Tropical Storm Bonnie.  Moderate vertical wind shear is contributing to the asymmetrical structure by tilting the circulation toward the northwest.  The wind shear is strong enough to inhibit intensification, but Tropical Storm Bonnie is extracting more energy as it passes over the Gulf Stream.  Bonnie could possibly intensify a little more while it is over the Gulf Stream.

The ridge east of Bonnie is steering the tropical storm toward the northwest and that general motion is expected to continue for another 12 to 24 hours.  An upper level trough approaching the ridge from west and the trough is expected to cause the ridge to weaken.  When the ridge weakens, the steering currents will also weaken.  Tropical Storm Bonnie could stall or meander for several days when that happens.

On its anticipated track the center of Tropical Storm Bonnie will approach the coast of South Carolina on Sunday.  The primary threats are coastal erosion, rip currents and locally heavy rainfall.  Persistent rain could create the potential for fresh water flooding.  Wind damage is likely to be minimal.  However, where the winds blow onshore, they could push water toward the coast and contribute to some coastal flooding.