During Hurricane Season, whenever there is a tropical system floating around, I get this question a lot: How do you know that it won’t come toward us?
And it can be a pretty straight-forward answer. Other times, not so much. But it always boils down to three main things.
And here they are, explained:
FURTHER ELABORATION
This is why whenever I post tropical forecast updates, you see a satellite image with a bunch of annotations on it. The circles, and letters and arrows are all indications as to what is happening in the atmosphere.
For example, in this image….
Shows the different placement of a ridge across three different operational models. And gives us insight into how Invest 92L will move.
Or this image….
Showing the mid-level flow around Tropical Storm Isaias. As well as the trough to the east of the system giving it a bit of a nudge.
Or this image of eventual-Hurricane Sally
And the notations in pink showing the mid-level flow, the two red circles indicating the areas of low pressure (on the left, a mid-level low and on the right eventual Sally) and the white lines as the ‘fence’ where Sally was going to have to move given the pieces in place.
All of these annotations are built on sound, repetitious meteorological observations. And those observations are supported by a foundation of basic Physics. So we know it has to work.
The degree to which is works is where the forecast can get a bit fuzzy. Because, as in the picture above, we can build a fence and we know a tropical system has to go through it… but we don’t know exactly where. And that is where things get more difficult.
But we do know that storms can’t just ‘hook a left at Albuquerque’ to quote Bugs Bunny. They have to follow the general rules of Physics.
