Major Hurricane Irma, Is She An East Coast Threat?

It’s the final day of August. For many of you, that might mean back to school, or perhaps the end of summer.  For most New England meteorologist and weather nerds in general, August 31st marks the anniversary of the last major hurricane to strike New England.  Some of you might remember Carol 63 years ago today. Two weeks later in 1954, another hurricane named Edna hit the same general area. Yikes. Imagine that?

So you might be asking, is major hurricane Irma a threat to the east coast?  The quick answer is yes, but it’s two weeks and 3000 miles away from any North America land mass.  To try to pinpoint a possible landfall anywhere in the US is impossible and would be irresponsible this far out.  We can however say with some confidence the storm will become a monster, and will be somewhere near the Bahamas next weekend.

We started watching now Irma when she was a tropical wave coming off of Africa last weekend. Here is her baby picture from Monday.

In only 30 hours Irma went from a tropical wave to major hurricane status. Tonight the storm is category 3 with winds of 115 mph located 1780 miles east of the Leeward Islands.

All indications are the storm will maintain major hurricane status and may even become a strong Cat 4 or weak Cat 5.   The steering currents in the tropics are weak, but there are important features forecasters will be monitoring to track the storm. First, a ridge of high pressure in the Atlantic will strengthen and back westward a bit in the coming days.  That will likely keep the storm on a westward journey.  Second, will a strong enough trough be present over US to shift the track north between the 10th and 15th?   Those answers are still unknown.  Here’s what we do know.  Forecast modeling is in very good agreement in a continued track west.  Each line indicates a different computer model. The thicker orange line is the Hurricane Center’s official track.

The most reliable model in my opinion would be the European model indicated by the white line above.  That track comes from it’s operational run this morning.  Models also have what we call an ensemble or set of forecast tracks. The European Model ensemble has 51 members.  Here’s the spread from today’s run.

Note the spread. Here are the projected locations of each of the 51 members of the European model next weekend. With some confidence, the model is indicating a storm track near the Bahamas.

Just a few days later on Tuesday the 12th, there’s very little confidence in any one track.

Here’s the same series of of maps from the less reliable US GFS model. It’s 21 ensemble members insist on a more northern track.

Saturday the 9th ensemble low locations. 

Tuesday the 12th Ensemble low locations.

Irma is headed into a favorable environment for strengthening which may make her a real monster just north of the Caribbean. If the storm goes over the Dominican or Cuba, the frictional forces would of course weaken the system.  A track just north of that though, look out near the Bahamas.   It’s impossible and irresponsible to forecast a track beyond next weekend.  Irma is very much a storm to keep a close eye one though in the coming days. You can always find our updates on  We’ll be over on social media is well.  Thanks for reading.


Charlie Lopresti

About Charlie Lopresti

Charlie makes up the "Weather Part" of CBS News 13s evening edition. A native New Englander, he grew up enjoying the area's exciting and sometimes wild weather.