HOUSTON – With every tropical system you will often hear meteorologists referring to the “dirty” and “clean side” of the hurricane. This is actually a scientific term for the portion of the hurricane that will see the most rainfall, highest storm surge, most tornadoes and often the strongest winds.
The dirty side of the hurricane is found in the front right and back right quadrants of a hurricane or storm. In order to determine the quadrants, you first draw a straight line with the storm motion. The storm motion is the direction in which it is traveling. Draw four quadrants with respect to the storm motion.
The front right quadrant is in the dirty side. The reason why this is the “dirty side” is because in the northern Hemisphere (where we live) tropical systems rotate counter clockwise. This means the air rotating around the low is saturated on the right side of the storm during landfall.
Below you can see where we are expecting our Gulf storm to travel in the next 24 hours. Houston is in the “dirty side” which will see much more rainfall compared to locations on the left of the storm.
On the left side you see dry air that has moved across land. The clean side will see significantly less rainfall. This is why when a hurricane hits Louisiana, we tend to stay dry and hot (think Tropical Storm Lee in 2011).
Below you can see an example of a hurricane hitting Florida. In this case, areas between Cedar Key and Tampa would be in the dirty side and would see the biggest impacts.
Make sure you stay weather aware this hurricane season. It’s always important to focus on the impacts of a storm, instead of the intensity.
