Carolinas at risk from tropical disturbance 99L
An area of disturbed weather (99L) that formed along an old frontal boundary appears to have developed into a subtropical depression, and may grow into a tropical storm over the next day or two. Strong upper level winds from the west are creating about 15 knots of wind shear over 99L, and satellite loops of 99L show the classic appearance of a weak, sheared system--a nearly exposed low level circulation system, with all the heavy thunderstorm activity pushed to one side by strong upper-level winds. This shear is forecast to remain between 15 and 25 knots over the next two days, which should allow some slow development. A QuikSCAT pass from 6:52am EDT showed that 99L has a vigorous closed circulation with top winds of 25-30 knots (30-35 mph), so in my book this system is already a subtropical depression. The reason I call it subtropical is because there is still clear evidence of a frontal boundary attached to 99L, evident as long band of clouds extending from the south side of the storm (Figure 2). The Hurricane Hunters are scheduled to investigate this system at 2pm EDT, and NHC may wait until then to see if 99L can maintain its strength before naming it a subtropical depression.