Sunday Evening update on Idalia

As expected the National Hurricane Center has issued a hurricane watch for parts of Florida. here are their Key Messages regarding Tropical Storm Idalia (en Español: Mensajes Claves). The watch (which means there is around 36 hours till tropical storm force winds, that hurricane conditions are possible, and you need to start seriously paying attention and in some cases doing stuff) includes most of the west coast of Florida. NHC shifted the track a bit more eastward and a bit faster, but the storm is still wobbling around just off of Yucatan, and so while the general direction is known, the specifics are still a bit fuzzy. Landfall intensity was bumped up to Cat 2, but that’s really a guess at this point since there are several factors working both for and against intensification, and as NHC itself says, landfall could be anywhere from a minimal Cat 1 to a Cat 3. Naturally, the usual suspects will seize on the high end of that estimate to gin up the FUD (Fear, Uncertainty, and Doubt) clicking. That said, Florida needs to pay attention as noted above.

Here’s the TAOS/TC impact swath map based on the 5pm forecast …

Idalia is already dumping wind and rain on western Cuba now as well as Yucatan, with some light damage. Cuba will see some more impacts overnight before the storm starts to definitively move off to the north. The damage swath has shifted south and east a bit in Florida with the fringes impinging on more populated areas, so the US damage forecast has doubled from $1 to $2 Billion USD. A further shift east will start to bring the Tampa to Crystal River coastline in to play, which will definitely trigger major disruptions and easily triple even that higher number. Not seeing any evacuation orders yet, but that’s likely overnight. In western Florida, be prepared to start acting in the morning on your local EMA guidance.

As for the Georgia/South Carolina coast, the basic threat picture remains the same as noted this morning, although the wind speeds *may* be a bit higher. Then again, if the trend continues and the track shifts more offshore, we will be on the weaker side and the winds would be lower! If I have time I’ll do a post on this, but given the structure of storms, the way rain wraps around and drier continental air is entrained, onshore vs. offshore winds, and other factors, a miss 75 miles inland by a weaker exiting storm can cause more damage to this area than a miss 50 miles offshore by a stronger storm! The time to start making decisions will likely be tomorrow evening for the GA/SC coast, we’ll see how things evolve overnight. The most likely scenario is still inconvenient, messy, hazardous in a few places where it usually floods, but with common sense not terribly dangerous unless you are very unlucky (which can, as we saw a few weeks ago, happen even in a run-of-the-mill thunderstorm).

Next Enki post will be Monday morning between 6 and 7 am.