Dry Slot

Post Mortem

Posted by: Bogon, 9:14 PM GMT on November 06, 2012

In the aftermath of the Frankenstorm, several WU bloggers have attempted a post-storm analysis. You might be interested in Barefootontherock's perspective, Bryan Norcross' commentary, or Christopher Burt's comparisons.

Doc Masters took a turn, as did guest blogger Lee Grenci. Why should I be any different?

The obvious answer is, "Please, no, I've had enough!" If that's how you feel, I advise you to click elsewhere. Here it comes. I promise to keep it short.

The interesting thing about Sandy was her transition from hurricane to nor'easter, or from barotropic to baroclinic storm. The difference is a matter of temperature. In a tropical setting all the air is warm. The classic tropical storm is a symmetrical pinwheel. In October off the east coast of North America, cold air is a factor. It's a baroclinic environment. Storms are lopsided. They adopt the yin-yang shape of the Taijitu.

The dividing line between tropical and temperate zones is the subtropical jet. As she moved north of the Bahamas, Sandy had to cross beneath the subtropical jet stream. That was the beginning of the transition.

At the time hurricane advisories reported that Sandy was subject to high wind shear on the order of fifty knots. In the animation above you can see a band of dry blue cutting across the neck of tropical orange on Sandy's southeast side. By the time Sandy reaches a position off the Carolina coast, the tropical connection has been completely severed. Sandy has become an island of tropical warmth in a temperate sea.

By the time Sandy passes Cape Hatteras, she has lost her symmetry. Cold air wrapping from west to east across her south side begins to displace the tropical air northward. As she approaches landfall in New Jersey, all of the tropical moisture is confined to an elliptical region on her north side. Here is an animation from my previous blog, which shows the process more clearly.

At landfall all of the milky white tropical convection gets swept into the broad rain band on the west side. What remains is purely baroclinic. A picture of the storm a few hours after landfall shows the yin-yang swirl of a nor'easter.

Categories: Autumn Hurricane Nor'Easter

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1. Bogon 11:45 AM GMT on November 07, 2012
It's a new day. I can stop being political now. Actually I stopped last Thursday. Early voting. Member Since: June 26, 2008 Posts: 72 Comments: 2761

2. Bogon 7:13 PM GMT on November 11, 2012
Ah-choo! Thursday night I came down with a cold. Since then I've mostly been sleeping or sitting in front of the television, punching buttons on the remote to stay ahead of commercials. The computer, the other great time sink in my life, has been running unattended. Thanks for not commenting. Nobody wins first post. Lately I've noticed several WU regulars have dropped out or announced that they are taking a break from blogging. I think it may be my turn. For a while there the words came easily. I was seeing the world in terms of how it might be translated into blog entries. That doesn't seem to be working now. I've run out of steam. All the ideas on my list seem stale and pointless. My mind is occupied by other things. I want to read a book. I want to view the world on its own merits, aside from its possible applicability to digital media. I'm not going to close the blog. I'll still drop by occasionally to moderate comments. The publication schedule is going to suffer. I refuse to put up new entries just for decoration. I'll post again when I have something to say. Member Since: June 26, 2008 Posts: 72 Comments: 2761

3. ycd0108 7:31 PM GMT on November 11, 2012
Hey Bogon: You gave words to how I was seeing the blogs - including mine - Mas o menos. I'm still "hooked" but find it harder to toss in a comment or make up something on my own blog. Could it be that we are maturing after the first blush? I think as winter sets in the urge to respond will increase - we'll see. For me this phenomenon - blogging and checking blogs here - is only a few years old. Things are moving along too fast for a four year old. Member Since: January 1, 2008 Posts: 142 Comments: 3435

4. Ylee 11:31 PM GMT on November 11, 2012
WU blogs in general has slowed down in the past year; many bloggers are more attracted to the relative ease of navigating FB, and do their socializing there instead of here. Putting out a new blog every two weeks or so can be a grind, but I try to take it as a challenge. Member Since: February 3, 2011 Posts: 65 Comments: 11298

5. Bogon 7:23 AM GMT on November 12, 2012
Well, shucks, just when I thought the well had run dry, I pumped out a dandy rant. A clog in the bowels of my mind came unstuck, and the resulting diarrhea-like efflux ensued. Ylee, there's some stuff in there about Facebook. ycd - You may be right about seasonal variation in blogging. It's a good time of year to get out of the computer room and enjoy the great outdoors. Member Since: June 26, 2008 Posts: 72 Comments: 2761

6. WunderAlertBot (Admin) 7:50 AM GMT on November 12, 2012
Bogon has created a new entry.

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