Hurricane Irma- United States

Bad storms bring out the best in people.

Sunday September 10, 2017

Fingers crossed, but I believe the destructive 10-15 foot storm surge that was expected along the Southwest coast of Florida never materialized for two reasons.  First, the storm made landfall on Marco Island/Naples.  The call Saturday evening was for the storm to track up/along/just offshore the coast.  The geometry of the coastline combined with a track like that made officials fearful of a devastating surge.

NHC 11 AM Advisory Hurricane Irma

There is a storm surge warning for all of South Florida on all sides.  Notice how this warning extends inland in Southwest Florida around Cape Sable in the Everglades.  This includes Everglades City, Marco Island, Naples, and Fort Myers.  Miami will see Biscayne Bay reclaim some of the city for its own around Coral Gables while the Atlantic takes Miami Beach.

Storm Surge Watch/Warning

Storm surge is not sea level rise.  Storm surge is the force of the wind/pressure on the ocean by the hurricane being forced onshore.  Damaging and battering waves arrive on top of this storm surge.  Storm surge and flooding from rainfall are the two biggest killers from hurricanes.  The red is at least 9 feet.  The NHC is currently forecasting 6-12 feet but with the westward shift they might go up a few.

NHC Storm Surge Threat Red 9 feet, orange 6 feet, yellow 3 feet, blue 1 foot

The trend today has been more to the west.  That means the highest water will shift towards Naples and Fort Myers.  Now onto what gets the headlines, the wind.  Irma is looking healthy on satellite.  Winds briefly fell to 150 MPH, but Hurricane Hunters have found winds to be at least 155 MPH making Irma a high-end Category 4.  This is really just semantics at this point as the storm likely fluctuate between 145-165 MPH until landfall.   The swath of hurricane force winds is large that Miami and Fort Lauderdale will still see winds of 100-125 MPH even with the center hitting the other side of the state.

It won’t get any better for residents of Central Florida.  Hurricane conditions are forecast for the entire length of the Florida Peninsula.  Tampa, Orlando, Jacksonville, and most of Georgia up to Atlanta will see at least gusts to Hurricane force as Irma weakens over the Southeast US.

It won’t be Harvey in regards to rainfall, but it will be enough for localized moderate to major flooding.

WPC forecast precipitation Hurricane Irma

This is a scary storm.