Tuesday, August 25, 2009

The Hiatus Is Over - Tropical Threat to East Coast?

Obviously it has been a long while since I posted anything here, mostly due to welcoming my second son into the world at the end of June, and obviously being pretty occupied on the home front since then. And of course there have been the usual commitments to the real job as well. But I am going to try and get back in the mode of updating periodically here, as we are headed for the more exciting time of year for many weather enthusiasts, which is the run up to the winter season!

But for now, it is still summer (which FINALLY came to the eastern U.S. this month), and we are still in tropical mode as well, even now with a threat to the East Coast perhaps! All eyes are on "Invest 92", an area of disturbed weather north - northeast of the Lesser Antilles, which is heading to the west-northwest currently. As of now, conditions are not all that favorable for development, at least not very quickly, but should improve over the next day or two, and I do think we'll have Tropical Storm Danny out of this. Now, where does it go? Well if you believe the U.S. models, it will turn harmlessly back out to sea. But other models say not so fast, and with good reason in my opinion. The GFS model seems pretty quick to develop this, and perhaps a bit north of where the true low level center will eventually wind up. Because a more developed system can be tugged north by any weak upper features, the GFS, by virtue of being faster with development, sends Danny-to-be off into the westerlies much faster, and stays well offshore. But given that the shear is not that favorable right now, I'd lean toward a slower development curve, and a path farther west. A pretty potent trough will dive into the Midwest this weekend, and that should mean we have enough ridging downstream in the western Atlantic, which also leads me to believe a farther west path, closer to the other modeling. This says to me that "Danny" has a much greater shot to impact the East Coast than Bill ever did, though I don't think this system gets as strong. It could organize enough to reach hurricane status, but the incoming trough should start adding enough shear to make it a tropical storm up the coast, so not the best of weekends at the coast, but where most people live in the I-95 corridor, it is probably more a rainmaker. What else will need to be looked at is the potential for the storm to interact with the incoming front and enhance rainfall even more, perhaps leading to some flooding concerns.

So the bottom line is that we should see Danny out of this, and my best guess right now would be a storm moving close to or into eastern North Carolina this weekend, then northward up the coast, probably as a tropical storm, presenting heavy rain concerns up the eastern seaboard, with most of the significant wind issues right along the coast.

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