Hurricane Irma update: Latest forecast track

Radar image of Hurricane Irma on Sept. 4, 2017.

As I discussed last week, there is a lot of incorrect and sensationalistic information associated with Hurricane Irma being put on social media by weather wannabees (also called “mediaologists” by some of my collegues).

One particularly nasty one mentioned that Irma might become the first Category 6 storm.  This would be laughable if Irma’s threat wasn’t so serious.  The Local4Casters know that hurricanes are very important to you:  some of you have trips planned down that way, some of you have property there, and some of you have relatives and friends there.  We will always bring you the latest, credible information about hurricanes.

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Here’s the latest forecast track from the National Hurricane Center:

As you can see, the path takes Irma very close to the Virgin Islands, Puerto Rico, Hispaniola and Cuba.  But don’t just focus on those little hurricane icons.  The gray area you see around those icons is the margin of error…Irma’s track is possible anywhere within the gray, although those icons represent the forecast’s best estimate based upon current model data.  Another thing to remember is that very dangerous conditions extend out far from where you see those icons.  Finally, keep in mind that strong hurricanes like Irma generate extremely high surf very far out from the storm itself…this will affect coastlines as well as cruise ships out in the Caribbean and Atlantic.

And what about the U.S.?  This graphic of various computer models shows the predicament that we meteorologists face:

Notice that some of the models track the storm west after Cuba, some of the models track it into Florida, and two of the models take it much farther north.  There is still tremendous uncertainty in the U.S. mainland part of the Irma forecast, although I think we’ll start getting a better handle on things starting on Tuesday.  Why so much uncertainty?  Because of a strong upper level trough of low pressure digging southward across eastern U.S. the rest of this week.  If that trough gets close enough to Irma, it can suddenly accelerate the storm to the north and then northeast. 

Although this is starting to look like a lower possibility, it’s still possible that Irma could recurve and miss the U.S. entirely.  The question we’re all trying to figure out is how much influence that trough will have on Irma’s eventual path.  If the trough digs less to the south than many models suggest, then Irma could conceivably continue westward into the Gulf of Mexico.  But more of the models suggest at least some northward component after the storm moves near Cuba.

One question I’ve had recently in the aftermath of Hurricane Harvey and now Irma is why we’re seeing the sudden onslaught of hurricanes.  This graphic offers the answer:

We are still approaching the peak of hurricane season.  We typically get a small handful of storms in June and July, then see things pick up as we progress through August and into September, before things start slowing down gradually in October and November.

The Local4Casters will continue to monitor Irma very closely, and keep you updated both on-air and online.


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