The Web Site and Blog of Ted Keller

Hurricane Irma Update 9-9-17

Hurricane Irma has spent the overnight hours making brief landfall on and hugging the northern coast of Cuba.

This has been a nerve-racking storm for Florida!  The whole state will see powerful impact from Irma but the question all week has been, when will it turn?  The answer has significant implications for maximum eye-wall winds and storm surge especially with regard to population centers.

The “cone” is something that appears on official hurricane track forecasts issued by the National Hurricane Center (NHC) and it exists for good reason.  As I stated in this blog earlier this week, Irma always had the potential to wind up on either coast of Florida.  Uncertainty increases with time when forecasting any weather event.  With hurricanes moving in a straight line, confidence is usually pretty high.  But when these storms start interacting with weather systems tracking in pretty much the opposite direction traveling over the U.S., it can be difficult to get the turn north exact.

The cone forecast exists to acknowledge such uncertainty.  Look at the forecast from the NHC issued on Monday included below.  Pretty much dead on!

Once the turn north begins today, the course will be locked in. It kind of reminds me of a game I used to play where a ball rolls between two metal rails which you adjust to try to get the ball to fall into a desired slot or hole.  Once it falls, your done!

Of course, the actual atmosphere is much more complex because there is interaction in a fluid (air) and reliance on forecasting, the accuracy of which degrades with time by its very nature.

With each hour that passes today, the western coast of Florida is under the gun. If Irma hugs the western coast of Florida, it actually puts the forward right quadrant of the storm in the worst possible place.  Just a tad more west with the track and the Tampa area would get hit dead on by this part of the eye.  Landfall in the panhandle of Florida is not out of the question!

Again, Irma is a relatively large storm so it’s damaging wind field will affect ALL of Florida.  Very warm ocean water lies ahead so the intensity should be pretty much where it’s been, or possibly ramp back up a bit.

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