I though Manuel would move westward, as East Pacific storms in that location often do, but it is moving more northward and will track a little bit inland over a part of the west coast soon.
Ingrid, over at the Atlantic coast, seems to be headed towards the same general region.
The Fujiwhara Effect
According to Dr. Wikipedia, meteorologist Sakuhei Fujiwhara discovered that when two cyclonic vortices (read, tropical cyclones) are near each other, they tend to orbit each other and close the distance between their circulations.
This is of more than academic interest – it’s the reason Superstorm Sandy, which had been headed happily out to sea, doubled back westward, toward the East Coast, when another cyclonic storm moved into the Southeast US (atmospheric conditions blocked Sandy from orbiting more to the north).
This is not to say that all Fujiwhara interactions are inherently catastrophic. Some are downright beautiful:
Effect on Mexico
While not a Superstorm Sandy situation, an interaction could make the current situation much worse for Mexico.
TS Manuel does have a westward component to its movement, and if left to itself might stay away from much of the Mexican mainland. However, Ingrid – a much stronger cyclone – could pull Manuel to the east, and then the two storms would merge over land, causing infalon rain and flooding.
Time will tell. This morning and later today I’m going to get the individual storm posts on the sidebar updated, and will continue this story, including the human impacts gleaned from online news sources, there.