2PM: Hanna The Meanderer…for now

Apologies for the later post; the day job has been hectic with storm stuff as well.

Tropical Storm Hanna’s been caught in something of a steering purgatory this afternoon; it continues to rain very heavily on the Turks and Caicos. As of the 2PM advisory, it’s moving SE at 2 MPH. We’re all awaiting the ridge of high pressure to build in and take it away — but it’s all a wait and see, still.

Intensity Rollercoaster

Hanna’s also been in a weakening trend; Gustav’s outflow has been negatively affecting it most of the day, having a great deal of its northwestern quadrant sheared off, helping to weaken the storm to tropical storm status earlier in the day. It’s held on as a 70 MPH tropical storm, so when the shear lets up, there won’t be much inhibiting it to becoming at least a minimal hurricane again.

This weakening has thrown a wrench in a lot of the forecast, though. The 11AM forecast discussion demonstrates significant uncertainty in the intensity forecast — it could barely hang on as a Category 1, or break free from the shear and blossom into a Category 3:

HOWEVER…GIVEN THE PRESENT LACK OF
ORGANIZATION…IT IS DIFFICULT TO KNOW HOW MUCH STRENGTHENING IS
POSSIBLE. THE NEW OFFICIAL FORECAST IS LOWER THAN THE PREVIOUS
ADVISORY BUT SHOWS HANNA BECOMING A CATEGORY ONE HURRICANE IN ABOUT
36 HOURS. IT SHOULD BE NOTED THAT THIS IS A LOW CONFIDENCE
FORECAST. IN FACT…IF ONE CONSULTS THE WIND SPEED PROBABILITY
PRODUCT INCLUDED IN THIS PACKAGE…IT CAN BE SEEN THAT THERE IS
NEARLY AN EQUAL PROBABILITY OF HANNA BEING A TROPICAL STORM OR
HURRICANE AT DAY 3.

A recon flight should shed much more light on Hanna’s structure; a flight’s scheduled for this afternoon and it probably is on the way in as I type. Here’s hoping that information is reflected in the 5PM.

Track Thoughts

The 11am advisory shifted the track back westward a little bit. Here’s the NHC’s map:

The NHC forecast track splits two groupings of model guidance down the middle. Here’s the high-carb meteorological pasta as of 3:15:

Computer Models at 3:00 Tuesday

One camp — with tighter agreement, I may add — takes an even more westward tack, bringing the center of Hanna onshore to central Georgia. Notably, the GFDL and HWRF models favor this scenario, with the GFDL taking a Category 3 just north of Jacksonville Friday. HWRF is a bit weaker, expecting a Category 2 storm. The other camp favors a Charleston-to-Myrtle Beach swath primarily. It’s a bit more divergent than the other two camps in terms of exact points, but remember, it’s still too early to get caught up in little jogs here and there. NHC has not adjusted the track much in part because Hanna’s size and intensity, as well as where it begins its movement from — remember, the storm has been meandering aimlessly southeast — has some bearing on how much and how quickly the expected high pressure will influence it.

Emergency Preparation

I caught Raymond from News 2’s tweets from the Charleston County EOC meeting. EOC has switched to OPCON 3, which activates the emergency operations center and indicates that an emergency situation is imminent. Mayor Riley is giving a press conference at 3:30 this afternoon; I recommend keeping an eye on News2’s Twitter. I’ll be watching that and will retweet big nuggets of information accordingly on both @chswx and @jaredwsmith.

Don’t forget about the video briefing tonight, tentatively scheduled for 9:15 PM. Sorry it’s so late in the night; I have obligations (read: class) to attend to from 7:00 to 8:15. This will give me an opportunity to review the 8PM advisory and break things down a bit better.

A special hello to those of you who came from The State — thanks for stopping in, and thanks to The State for syndicating this blog on their Web site! I hope folks are finding this useful; I know I’m enjoying doing it. :)