Help me settle a lunchroom discussion

[KG4HPN]

When can a hurricane be said to have made landfall? Is it when the edge of the eyewall reaches land, or when the center of circulation does? The lunchroom is pretty evenly divided on the issue, and I'm too much of a complete newb to be able to provide the definitive answer they were looking for.

Thanks!

[RL3AO]

That would be the center of the circulation. So when the center of the eye hits land, its said to have made landfall.

[CajunMama]

I was under the assumption that it was when any part of the eye hits land. I've been googling, looking for the answer. I did find a really interesting page for the novices.

FAQ's about hurricanes

[AJC3]

You can find the answer here...

http://www.nhc.noaa.gov/aboutgloss.shtml

Landfall:
The intersection of the surface center of a tropical cyclone with a coastline. Because the strongest winds in a tropical cyclone are not located precisely at the center, it is possible for a cyclone's strongest winds to be experienced over land even if landfall does not occur. Similarly, it is possible for a tropical cyclone to make landfall and have its strongest winds remain over the water. Compare direct hit, indirect hit, and strike.

Direct Hit:
A close approach of a tropical cyclone to a particular location. For locations on the left-hand side of a tropical cyclone's track (looking in the direction of motion), a direct hit occurs when the cyclone passes to within a distance equal to the cyclone's radius of maximum wind. For locations on the right-hand side of the track, a direct hit occurs when the cyclone passes to within a distance equal to twice the radius of maximum wind. Compare indirect hit, strike.

Strike:
For any particular location, a hurricane strike occurs if that location passes within the hurricane's strike circle, a circle of 125 n mi diameter, centered 12.5 n mi to the right of the hurricane center (looking in the direction of motion). This circle is meant to depict the typical extent of hurricane force winds, which are approximately 75 n mi to the right of the center and 50 n mi to the left.

Indirect Hit:
Generally refers to locations that do not experience a direct hit from a tropical cyclone, but do experience hurricane force winds (either sustained or gusts) or tides of at least 4 feet above normal.

[KG4HPN]

Thanks Tony, and everyone else who answered. I've already had my helping of crow here at work for this hurricane season. I could have sworn it was the intersection of the eyewall with land. Now I know better!

I'm going to have to work to restore my credibility with the bosses though, because they tend to make decisions about what to do (allowing employees to go home to prepare, closing, etc) based on my recommendation.

And that's where all you lovely people come in. I've enjoyed reading all of your discussions and whatnot since '04, when everyone in FL suddenly became REALLY interested in learning more about hurricanes. While I can't read models and whatnot, I do enjoy watching you all parse them and lay out different possibilities.

Thanks again!

[vbhoutex]

I learned something today(and I am supposedly knowledgeable about weather and the tropics). I had always thought landfall occurred when the eyewall passed onto land as opposed to the center of circulation. I remember when several of our members including me were following Ivan in and we called landfall when the eyewall crossed onto land. I guess we were wrong a few miles and several minutes at a minimum as to what actual landfall was.

[pojo]

yes indeed it is the center of circulation.