whether the weather's blog

hanna, and dare i say, ike

 abuse

Things are getting tougher and tougher with Hanna.

The 11 am advisory from the National Hurricane Center is still differing from that of AccuWeather and the Weather Underground to the extent that it is worrisome.

The NHC has a tighter cone of probability farther to the left, but with a flatter curvature, than the 5 am advisory, and the prediction that Hanna will reach minimal category 1 status at landfall. Both other services have a wider cone of probability, pulled to the left as well, with AccuWeather is calling for a category 2 status while the Weather Underground is placing it at a strong tropical storm with a 60 percent chance of developing into a minimal hurricane. All three have slowed the forward motion until Hanna is well into North Carolina and makes that turn to the northeast. That will diminish the additive effect of the forward speed combined with the wind velocity of the circulation itself, but will produce more rainfall.

The problem involved in projecting the path of this storm involves a building high pressure system developing over the western Atlantic. The track of Hanna is almost completely dependent on how strong that high becomes and exactly how it develops. And I say “almost” completely intentionally.

There is an additional factor involved in the form of Gustav. Remember him? Well, Gustav is alive and well and approaching the Ohio Valley from its current position in the lower Mississippi Valley area. That low pressure remnant of Gustav can have the effect of “grabbing” Hanna and moving it farther inland or reducing the angle of the curve it is expected to make to the northeast. I am wondering just how much the various models are accounting for that influence?

So what’s it gonna be? A category 2 storm passing over Raleigh or a strong tropical storm passing us by completely off the coast? Or maybe somewhere in the middle as a minimal hurricane hitting Wilmington and raking the Outer Banks? Who knows? And even if we knew, it wouldn’t make much difference because of the shear size of the storm. Those winds and rain shield extend far from the eye.

My gut feeling is a landfall as a middling category 1 hurricane somewhere between Myrtle Beach and Wilmington with the eye passing between Raleigh and Rocky Mount before it curves hard to the right and exits North Carolina somewhere around the Virginia border. Do I have anything to really back that up? Not really, other than the memory of Fran in a similar configuration with a high pressure system to the east and a low to the west making it do things that no one predicted it would do. But in light of what is to potentially follow, who cares?

I never though my concern over an approaching hurricane would significantly diminish until after it had cleared all possibility of striking me, but let’s talk Ike.

I don’t like Ike. Ike is a monster category 4 storm currently out in the Atlantic. But it is creeping closer to land. The issue becomes, which land?

Two days ago, I had not heard a single forecaster say that Ike was going to do anything but move into the Gulf after creeping by south Florida. Now, they all have Ike making a nice turn to the northwest come this Sunday. It is still way too early to tell what will happen after Tuesday or so, but the current trajectory combined with that same high pressure system pulling Hanna into its periphery will probably be affecting Ike as well. To what extent it will affect the path is anyone’s guess at this point, but I’m not really all that comfortable with a category 4 hurricane that has even a minimal potential of slamming us.

By day five of the forecast, the NHC is projecting some weakening to a middling category 3 storm, but then Ike enters into warmer water and the shear looks like it might abate to the north of the islands. That would lend to strengthening again to whatever it may want to strengthen to.

Again, his is gonna be an interesting week coming up.