Why do hurricanes like Helene spin off tornadoes? NBC 5 Chief Meteorologist Rick Mitchell explains the science behind it and which part of the storm is most at risk for twisters.
Much of the Florida Peninsula is under a Tornado Watch as Hurricane Helene moves northeast toward landfall. The storm's position in the Gulf of Mexico, west of the state, could be a significant factor in issuing these watches.
When analyzing a hurricane, the northeast quadrant is often the most active for tornado formation. This is due to the strongest winds occurring in that area as the storm advances. Tornadoes in this region are typically rain-wrapped, hidden within the outer bands of the hurricane.
In that area, there is heightened wind shear, characterized by wind speed and direction changes. High-speed winds in the upper atmosphere can move in one direction, while surface winds may flow in the opposite direction, creating a horizontally rotating tube of air. If this rotating column is caught in the storm’s updraft, it can be lifted vertically, forming a tornado. While these tornadoes are generally not strong or long-lived, multiple tornadoes can form simultaneously within a hurricane.
At about 5:30 p.m., Helene strengthened into a Category 4 storm with sustained winds of 125 mph.
Get top local stories in DFW delivered to you every morning. Sign up for NBC DFW's News Headlines newsletter.
Hurricane Helene is a large storm and boasts a diameter of more than 400 miles, placing it in the 90th percentile for size among storms of this category at this time of year.
