Idalia Catch-up, Thu 31 Aug

Didn’t get to post an update last night, was on backup power, then lost the main internet link. The office has a backup satellite internet connection, but that is reserved for high-priority traffic so didn’t get to post more than a quick note.

Idalia is now moving offshore of North Carolina, and the rains are moving out with it. Still getting some flooding in its wake, here are recent radar and a satellite image at sunrise …

click any image to embiggen
Idalia (blob off of NC), Franklin, and newly developed fish-storm Jose on the right

The structure of the storm was rather unusual – a dry slot developed along with a coastal front type structure that kept most of the rain inland, away from the Georgia coast. In midtown Savannah I only got 1.5″ of rain, where the forecast was for upwards of 4″. Across inland GA/SC there was a *lot* more, it seems flash floods and runoff cause a lot of problems. In fact, according to the MRMS radar composite estimate, some areas got over a foot of rain yesterday!

MRMS Rain swath for Hurricane Idalia

On the coast from the ocean side, at least in Savannah the peak tide was at least a foot below forecast because Idalia was moving a bit faster than predicted, and the winds reversed before the high tide arrived. We saw 9.43ft at Pulaski instead of the forecast 10.5:

Savannah, a foot below forecast.

Further north, where the storm timing was closer to and after high tide, storm surges were higher – in the Charleston area there was significant coastal flooding, reports are 2-3 feet in to McClellanville. But of course nothing like Florida.

Charleston, at least a foot about the prediction …

There is certainly wind damage across the area, but in perspective it is relatively light unless you were the one that got hit. I’ve seen reports of 55mph gusts on the coast, but at the office station we peaked in the low 40’s. A few tornado reports, will have to wait for NWS to assess them to see if that’s what they were or some other storm related wind vortex – while that matters to the research, again not much difference if it’s your roof that came off. Reports are that there are still around 300,000 people without power across the storm path.

Structurally, Idalia was really more of a Cat 2 than at Cat 3 at landfall, although it seemed to have areas of Cat 3 winds reaching the surface. Again, that’s just a technicality if you were in the landfall impact zone. Areas around Cedar Key saw a storm surge of upwards of 15 feet, and there are reports of major damage. Inland, the vulnerable areas around Perry saw a lot of damage. As warned, there and in far south Georgia there is a lot of manufacture housing (mobile homes), and those tend not to perform well in high winds. There will be a lot of people who need long-term assistance in that area, hopefully our attention span won’t wander before they get it.

The economic impact looks to be in the $10 to 12 Billion range – less from wind than predicted, but more from inland flooding than was expected due to the structural weirdness noted above.

Elsewhere, Bermuda is feeling tropical storm winds from the fringes of Franklin and Idalia is headed that way next, likely as a tropical storm .

Will do another update this afternoon when things calm down a bit.


  1. Thank you for your storm comments and updates. I tend to have Hurricane PTS, and your reporting lessens the drama that is usually present in other reporting.
    Thanks again!

  2. Thanks so much for your thoughtful, helpful, well-composed updates! They were a breath of calm sanity amidst the media’s Idalia hype.
    Stu and Kathy

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