2024 hurricanes

H. Helene is still in the news. I happened to read an article somewhere on internet saying “Florida panhandle and Florida Keys have no hurricanes”. I hope it was written by AI because humans can’t be that clueless (right?). Whence sprang first of a possible series on regional storm swaths, N. Florida including panhandle this time. It begins in 2004 with Ivan, and such analyses cannot start much earlier because Natl Hurricane Center did not archive wind swaths. Tropical storm (TS) wind swaths are the less-scary color. Heavy rain and coastal storm surges came with each storm, but are not shown.



2004 H. Ivan was big and has only faded by comparisons with worse 2005 hurricanes nearby. From 2006 through 2015 the region had no hurricane winds, and several years had not even TS winds. But it would not have been wise to generalize from lulls. This region has been frisky since 2016 H. Hermine and has not calmed. Yet it would not be wise to suppose that global warming is a singular cause either. North Atlantic storms are higher overall from this with some confidence. But of about 100 hurricanes and several hundred TS during, most go elsewhere. Global warming has its thumb on the scale but it is a big thumb and not specific to regions.

We can see something in this about how far hurricane winds reach inland. H. Helene may have reached further than earlier Michael and Idalia, but not by a lot. I had wondered about that.

In summary, this region gets average one TS per year and one H per 3 years. I suppose a large fraction of total rain comes from them. They are not ‘just another Tuesday’.

 

1916 was the previous historical analogue:

Worse Than 1916": Helene Shatters Asheville's Flood Record – iWeatherNet,

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Oh Baaab. Adiabatic lapse rates are 5.3 oF per 1000 feet (dry) and 3.3 oF per 1000 feet (wet). In common scientific units, 10 oC/1000 M and 6 oC /1000 M (dry and wet). As average atmospheric is between dry and wet, one can manage with a single number, 6.6 oC /1000 M. Easy enough to remember especially if you fudge it a bit to 6.66 (sign of the EkatosBeast )

Many 'pop' explanations of mountain effects on air (and thus its water) refer to it being squeezed. This is amusingly opposite of true. Instead the lifted air is unsqueezed, allowed to expand, as there is less weight of atmosphere above it to do squeezing. So that parcel of atmosphere expands, cools, and loses some capacity to carry water vapor. What was ocean water a day or so before falls as rain on windward mountain slopes, gravity sends it back towards the nearest ocean, and folks near local river conduits observe it (and sometimes their houses) making the trip.

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The surprising thing for me is that it took about 107 years for history to repeat itself on this scale. A lot of large tropical storms track up the E coast and even offshore (1916 villain was offshore until Rhode Island). Many of those would have sent seawater-evap towards Appalachians and on similar journeys.

Maybe the mountains are just too dang small. They were much taller during the squeeze (real squeeze) that build Pangaea. 250 million years of hurri-caning have worn them down.

 

Oops. 1916 precursor storm that wetted up soils was offshore. The big boy was #4

https://www.tropicalweather.net/picts/seasonal/1916-tracks.PNG

 

Once again, west Florida's pleasure craft fleet has no way of knowing that they ought to relocate. Before Wednesday->Thursday (soon to be) H. Milton focuses attention on Tampa Bay area. Paradise Lost indeed.

 

Hillsborough and Pinelas counties combined population 2.45 million

Florida County Map and Population List in Excel

 

Tampa to Naples about 130 miles. I hope you are not underestimating the size of this harm's way.