Florence and the Hype Machine

No need to panic

Jared Smith
Sep 5, 2018 · 4 min read
Category 4 Hurricane Florence churning away in the Atlantic. Image: Colorado State University

You may have heard of a storm called Hurricane Florence recently. It is out in the Atlantic and is pretty far away from any landmass, much less the east coast of the United States. It’d be over a week or more before we’d even get into the realm of possibility as far as potential impacts.

That has not stopped several outlets of varying prominence from writing stories that cherry-pick scary model runs to say that the East Coast could get hit with a major hurricane next week, and then ignore subsequent runs that show nothing of the sort. So, let’s go ahead and get some facts out there and then talk realistically about what these model runs are telling us.

5PM advisory on Hurricane Florence from the National Hurricane Center.

As of 5PM, Florence was packing 130 MPH maximum sustained winds — a Category 4 storm on the Saffir-Simpson wind scale. It is moving NW at 13 MPH, with some weakening expected over the next couple days. If you have plans for Bermuda next week, be monitoring Florence closely.

Why meteorologists are a bit concerned

ECMWF EPS verification and probabilistic forecast for Florence’s intensity. (It’s not working out too well.) Source: Brian Tang, UAlbany

Florence hasn’t behaved very well from a forecast perspective — not only is it significantly outdoing all intensity forecasts, it is also running to the north of the guidance consensus. This is a double-edged sword: the further north the storm gets, the more likely that it could take advantage of a trough that is expected to arrive early next week and turn away from the US. The stronger the storm, though, and any miss of its escape route could be troublesome for land.

Complicating matters with the potential for recurvature is the presence of a strong ridge of high pressure to Florence’s north. If it strengthens, it is likely to drive the storm further west. This is a particular forecast detail (in addition to the storm’s intensity) that the models are having an extremely tough time nailing down.

“What does this mean for me?”

12z EPS ensemble performing a giant shrug of the shoulders as far as track beyond five days. Source: Brian Tang, UAlbany

Ultimately, we really don’t know what Florence is going to end up doing right now. Guidance — yes, even King Euro — is all over the place beyond five days. In the EPS ensemble chart above, you see solutions ranging from Florida to Nova Scotia landfalls as well as recurvature to sea (which appears to still be favored, by the way, as indicated by the tighter cluster of plots and the lighter colors, indicating higher probabilities).

So, here’s what you should do right now:

  • Don’t panic and go on about your life. We have a lot of time to watch this storm, and the odds as they stand right now continue to favor it not being an issue for us (aside from perhaps some surf or rip currents). Let the weather folks distill the data down and produce forecasts; we’ll give you the lowdown if something begins to look like a real concern.

Hopefully, this will be all I need to write here regarding Florence, but if not, I’ll carry updates here as well as on Twitter as needed.

Try to enjoy the rest of your week. :)


Follow Jared Smith’s Charleston Weather updates on Twitter, Instagram, and Facebook. An updated forecast and current conditions are always available at chswx.com, too. Bookmark it on your home screen! To support independent, hype-averse weather journalism, consider becoming a patron on the Charleston Weather Patreon page.

Charleston Weather

Weather forecasts and discussions for the Charleston, SC Tri-County area (Berkeley, Charleston, and Dorchester).

Jared Smith

Written by

Software engineer and weather geek. Dev team manager @BoomTownROI, principal nerd @chswx.

Charleston Weather

Weather forecasts and discussions for the Charleston, SC Tri-County area (Berkeley, Charleston, and Dorchester).

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