Tropical To Extra Tropical Storm Development – The Most Dangerous Weather Pattern


We have mentioned in the past that while hurricanes get the press, their area at sea is limited and they are relatively easy to avoid. If the tropical system morphs into an extra tropical configuration, it covers a huge area, and is nearly impossible to get away from. We have a perfect example of this right now.

If you go to you will find the most recent complete weather fax run from the Marine Prediction Center in the USA. The surface weather analysis shown above represents the remnants of tropical storm Maria, centered between Newfoundland and Greenland. It is orders of magnitude larger than Maria was, and has moved at speed of 40 to 50 knots over the last 24 hours.

You would not want to be caught unawares by one of these systems.

There is lots more on this subject in Mariner’s Weather Handbook.


Posted by Steve Dashew  (September 17, 2011)

4 Responses to “Tropical To Extra Tropical Storm Development – The Most Dangerous Weather Pattern”

  1. Mike Says:

    That is fascinating. And frightening. And new to me. Thank-you!


  2. Steve Dashew Says:

    Hi Mike:
    It is interesting that these situations do not get more play in the press. Another issue is dynamic fetch where a fast moving storm system tgravels at the same speed as the waves propagate, creating seas all out of proportion s ie wise to what might be expected. A fast mover like this is a candidate for dynamic fetch waves (there is a chapter on this in our Surviving the Storm book).

  3. Mike Says:


    Do you think folks who rely on GRIBS as their only source of weather would have caught this?


  4. Steve Dashew Says:

    Hi Mike:
    Maybe yes, maybe no. But raw models by themselves are only one part of the puzzle. Most important is the 500m data which often contains the clues to these events.