Last night NHC started advisories on Potential Tropical Cyclone Nine, likely to become tropical storm Imelda. It’s now definitely a threat to the Bahamas and probably the southeastern US as well, but how bad isn’t at all clear yet. Will do two updates today, while the overall situation is a bit clearer, we’re likely to have a system skirting the coast of the US and there are some aspects that will control what the impacts are that are very difficult to forecast. So this post will be short, with more to come this afternoon.
As always your best summary of information is the National Hurricane Center’s “Key Messages” product: Key messages regarding Potential Tropical Cyclone Nine (en Español: Mensajes Claves).
Note that tropical storm warnings are now up for all of the Bahamas. Given the slower speed, watches might not go up for any US locations today, but be alert for them at any time, and be aware that both governments and private sector are already starting to take actions in anticipation. States are already starting to take action, for example, South Carolina declared a state of emergency, which allows agencies to suspend normal budgeting actions and regulations as “needed”. Given these are politically driven actions as much as data/meteorology/safety, I can’t always anticipate what might happen the next day or two, only tell you what the physical impacts are likely to be. So let’s look at that …
The storm still hasn’t developed a distinct center, so there is some uncertainty about the track. While the major global models such as the beloved European Centre model (ECM) and much maligned yet often correct US Global Forecast System (GFS) model both show a stall and turn out to sea, the detailed regional models are still showing landfalls on the Georgia/SC coast …
The latest two GFS runs don’t show as much of a stall as the official NHC forecast, but a reasonably fast turn out to sea.
Probably the biggest factor for the impacts to Georgia and South Carolina, in particular the area popularly known as the Frogmore Region (Brunswick-Savannah-Charleston), is how much dry air is entrained in the system. Here is the water vapor band this morning:
Notice the band of very dry (brown) air over the northern Gulf of Whatever and southeastern US? if that dry air is sucked in to future Imelda, rain on the south and west side will likely collapse and only areas to the east and north will be inundated. On the other hand, if the wet air from the Gulf (white band just south of the brown band) gets pulled in, the entire storm will be wet. This is just one of the complicating factors in trying to figure out what is going to happen next week.
The bottom line right now is that although there is still some uncertainty, most of the scenarios have future Imelda traveling up through the Bahamas as a tropical storm, perhaps becoming a minimal hurricane (and you can be sure NHC will upgrade it if there is any sign that is possible). By Tuesday it looks like the storm will be just off the coast of Georgia, where it looks to stall, perhaps briefly, perhaps for a couple of days. The exact location will be critical as to who gets coastal flooding and epic rain – with the rain being heavily influenced by the dry air noted above.
By far the best way to get this commentary is to subscribe to the emails, which is the best and only really reliable way to get them. You can also donate to keep it going at this the same link. Subscribers will be getting a link to a special page with real time radar, lightning (including lightning forecasts), satellite data, and other cool stuff later today.
You can also follow us on X/Twitter (@EnkiResearch), Telegram, BlueSky, or even Facebook if that’s your preferred social media mayhem.
Good update…thank you!
Thank u so much. So over the doomsday barons
Hi Chuck – always appreciate your insights. I was interested in seeing what the local model shows, but we only got the /home/chuck/ link, not the image in the email that went out this morning. I see the image now that I’m on the blog.