Hurricane Ian and Tampa Bay

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News Brief by Kip Hansen – 27 September 2022 (updated 8:10 pm)

Updates are below main news item. Anthony Watts has posted the live radar video feed here.

click here for latest NOAA image ]

Hurricane Ian is projected to run right up the mouth of Florida’s Tampa Bay, making landfall as a Major Hurricane.  The threat presented by this hurricane depends on precisely where the eyewall hits which also determines which direction the strongest winds are blowing when it makes landfall.

If Hurricane Ian hits Tampa Bay, just north of the Lower Tampa Bay (see map below), the strongest winds, and thus the greatest amount of storm surge will be pushed up into the shallow Upper Bay, potentially causing widespread flooding for the portions of the surrounding cities, many of which are built on old flood plains just a few feet above Mean Higher High Water – the highest of Tampa Bay’s usual high tides.

NOAA’s projected tracks improve as the time window gets smaller. At 72 hours out, these projections are accurate to about 100 miles.   On Sunday, Ian was projected to hit Florida where the panhandle joins the main north-south body of the state.  Now it is targeted directly at Tampa Bay with just over 48 hours remaining to landfall.

As you can see, Tampa Bay is very shallow — 1 to 4 meters at the deepest.  [See this nautical chart] There are barrier islands along the Gulf shore, off Clearwater and Largo.  They will be entirely submerged by anything more of six feet of surge.   Large parts of Pinellas Park, single family homes most of it, will be flooded, along with almost all the bay-facing neighborhoods.

Using the NOAA Sea Level Rise viewer, first at Mean Higher High Water, then with five feet of storm surge and finally with an unlikely, but possible, ten feet of surge.  The very-light blue areas are inundation.

Only time will tell.  While a  50 mile shift north or south will make the world of difference for the Tampa/St Petersburg area, a major hurricane hitting this area, which has been spared a major hurricane event for nearly a century, will be a true disaster and create a real crisis as homes are destroyed and perhaps millions lose electrical power for a week or more.

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UPDATE: 8 pm Tuesday:

With just 18 hours to landfall, Hurricane Ian is already classified as a Major Hurricane and the track projected takes the eye right into Gasparilla Sound (small map above). This lets Tampa/St Pete off the hook for the worst of the storm, but now Punta Gorda, Sanabel Island, Cape Coral and Charlotte Harbor will bear the brunt of the landfalling eye.

Of course, the track is not set in stone by the projections. It can and often does shift in the last 24 hours — sometimes by quite a bit. In any case, the folks in western Florida south of Tampa are in for a rough ride.

It is not only the coastal cities that are in danger — Arcadia and Lake Placid and pints inland will still get a hurricane, and as the storm loose hurricane status, it will still be a dangerous storm as it tracks up through central Florida.

UPDATE: 5 pm Tuesday:

Now just 24 hours or so before landfall, Hurricane Ian is again tracking a little further south than 3 hours ago.

The eye is shown to be striking Florida just about right at the mouth of Gaspirilla Sound – Charlotte Harbor.

The latest discussion of Hurricane Ian on the NHC site says:

“I should note that whether Ian comes ashore as category 4 hurricane or a large category 3 after an eyewall cycle, avoiding a large and destructive hurricane for Florida seems very unlikely, and residents should heed the advice of local emergency management officials. The new forecast necessitates a Hurricane Warning for portions of extreme southwestern Florida, and a Tropical Storm Warning for the rest of southeastern Florida that wasn’t previously under a warning.”

UPDATE: 2 pm Tuesday:

Some but very little change from 11 am. The landfall has shifted a tiny bit further south, which is better for Tampa/St Pete but worse for Sarasota, Venice, Englewood, Port Charlotte Harbor and Punta Gorda.

This southward shift means the highest winds and strongest surge will be into the Gasparilla Sound/Charolette Harbor.

Landfall is less than 48 hours out, so the modelling of the landfall should not change very much. The last little shifts, north and south, will occur in the last 24 hours.

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UPDATE: 11 am Tuesday:

The 11 am path projection for Hurricane Ian now appears to be shown as making landfall just south of the Lower Tampa Bay, which puts the highest winds and largest amount of storm surge down between Sarasota and Port Charollette/Punta Gorda. [ map ]

That’s a good thing if it comes to pass. Good for Tampa Bay bad of Punta Gorda which is at the head end of a long bay and may sufferer the same fate as feared above for Tampa Bay.

Author’s Comment:

I lived in this area long ago, and my first child was born there.  Somehow Tampa/St Pete was known as a hurricane safe area.   It had not suffered a direct hit since 1921. 

I hope the residents there will prepare well and follow evacuation advice early.

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via Watts Up With That?

September 27, 2022