3
$\begingroup$

Question says it all really. It appears that every hurricane hitting the US East Coast directs itself north once on land.

  • Hurricane Florence is predicted to hit North Carolina then turn toward Canada
  • Katrina -> Floridan and Louisiana -> Great Lakes
  • Dennis -> Florida -> Great Lakes

enter image description here

$\endgroup$
5
$\begingroup$

It is mostly due to the Coriolis effect (aka Coriolis Force). (Another reference here) Because of the Coriolis Effect, parcels of air (think of boxes of air) in the northern hemisphere are deflected to the right. This means that air around the subtropical ridge over the Atlantic ocean circulates clockwise.

Think of a tropical cyclone as a parcel, or box of air. It tries to complete the clockwise rotation around the subtropical high.

Now, inevitably someone will say 'Aha! I know of a storm that actually moved south.' Yes, different things can cause tropical cyclones to move in strange directions, such as the Fujiwhara Effect, other meteorological features. But by and large, the Coriolis force is the dominant cause of the curvature of the path of tropical cyclones.

It is also worth pointing out that the hurricane also has parcels of air inside of it. The Coriolis Force acts on that too, promoting rotation.

$\endgroup$
  • 1
    $\begingroup$ Agree with BarocliniCplusplus. Also friction plays a huge role. Over the ocean, these hurricanes will normally move in a straight line because the friction is very low. As soon as the hurricane makes landfall the friction increases and therefore deviates North. $\endgroup$ – Jaun van Loggerenberg Sep 14 '18 at 16:10
  • $\begingroup$ @gansub The latitude cyclones form at is probably more of a climate question. My guess is yes, but I can't be certain.Its worth noting that it didn't form at such a high latitude, but it was able to move through the usually hostile subtropical Atlantic ridge. $\endgroup$ – BarocliniCplusplus Sep 15 '18 at 21:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.