Future Storminess in a Warmer World

February 26th, 2018

Year 1: 33, 34, 38, 42, 44, 49, 57, 61, 68, 71

Frequency (FRQ): 10 hurricanes

Intensity (INT): 61 m/s, 20% are stronger

Year 2: 36, 39, 55, 68, 75

Frequency (FRQ): 5 hurricanes

Intensity (INT): 68 m/s, 20% are stronger.

• Single metrics of storm activity mislead.
• How often and how strong are two canonical components of storminess.
• Putting frequency and intensity on separate axes illuminates an empirical space of storm variability.
• The fingerprint of climate change on storminess is fewer, but stronger.

• An estimate of how strong a tornado can get requires a continuous scale of intensity.
• The EF damage scale is categorical.
• We can count the number of tornadoes by EF category.
• But a plot of the number of tornadoes by EF category over time fails to answer the question: Are tornadoes getting stronger?

\[ E = A_p \rho \sum_{j=0}^{J} w_j v_j^{3}, \] where \( A_p \) is the path area (width times length), \( \rho \) is air density (assumed to be 1 kg/m\( ^3 \) at the surface), \( v_j \) is the midpoint wind speed for each damage rating \( j \), and \( w_j \) is the corresponding fraction of path area.

Credit: Dayton Daily News