Andrea brings threat of isolated tornadoes

HORRY COUNTY, SC (WMBF) - Almost all tropical cyclones making landfall in the United States spawn at least one tornado, and Tropical Storm Andrea is no different. Several tornadoes have already been confirmed in Florida, and that threat will follow the storm as it moves northeastward toward the Carolinas.

According to the National Oceanic and Atmospheric Administration, tropical cyclones spawn tornadoes when certain instability criteria are met. Because of vertical shear in tropical cyclones is very strong at low altitudes, the combination of instability and wind shear can become favorable for the production of small supercell storms, which have an enhanced likelihood of spawning tornadoes compared to ordinary thunderstorm cells. Most tornadoes form in outer rain bands, usually about 50 to 200 miles from the tropical cyclone center.

In most tropical cyclones, the area in which tornadoes are most likely to form is the northern and eastern sides of the center of circulation. This is why there is some concern for isolated tornadoes in the Grand Strand and Pee Dee- the National Hurricane Center forecasts the center of circulation will pass somewhat inland, just to the west of the beaches. That means there is an elevated risk for tornadoes in the area.

Because there will be a slightly increased risk for tornadoes, it is important to be prepared. This is not a reason to panic, but you do need to take precautions now and have a plan in place as to what to do in the event that a Tornado Warning were to be issued. If this becomes the case, remember your tornado safety guidelines- seek shelter inside a sturdy home or building, away from doors and windows. Go to an inside closet or bathroom that does not have any outside walls; put as many walls between you and the outside of the building as possible. Cover yourself with a blanket and pillows to protect you from flying debris.

Right now, it appears that the time of highest threat for tornadoes is early Friday morning, around 12 a.m. to 8 a.m. Because most people will be asleep throughout the night, it is important to have a way to receive warnings that will wake you if necessary. A NOAA Weather Radio is the best option, but there are also smartphone apps that can alert you to severe weather, including the WMBF Storm Team app, which is free to download.