When is Landfall "Landfall"?

[clearwater]

All morning various news people have been stating that Frances "has begun landfall" "has already made landfall" "won't make landfall for hours, yet"...

And it has made me wonder if there is an "official" definition of "landfall" and if yes, what is it?

TIA.

[Brent]

When the center of the eye comes ashore.

[clearwater]

Thank you, Brent.

[vbhoutex]

I would like to see an official definition from somewhere like NHC. My understanding is that landfall is made even if part of the eye-the area inside the eyewall where it is calmer, etc.-comes ashore then landfall has happened. Brent's explanation makes sense, but I am putting in my .02 worth too and wondering also what the "official" definition is.

[Brent]

This is what the NHC glossary says:

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.

[Anonymous]

Probably when the area of lowest barometric pressure crosses the coast, I would guess.

[Indystorm]

By the definition stated above Alex did not make landfall over Ocracoke Island in the outer banks. I read somewhere that the eyewall grazed them but the center of lowest pressure did not affect U.S. land. Thus we may not have officially had a landfall from Alex. For this reason persons need to remember that the strongest winds are in the eyewall which can reach you long before the center of the eye, particularly one as large as Frances. This gets misleading when TPC keeps talking about landfall and means when the center of the eye comes over a given area. That's when you have your calm after having the initial severe lashings from the eyewall, which can occur hours earlier. The media compounds this confusion.

[KeyLargoDave]

Also look at the definition of "direct hit." I believe they define that as being in an area 3x as wide as the maxwind field around the eye (1x to the left and 2x to the right of the eye).

[HurricaneQueen]

It would appear to me with an eye as huge as this one, landfall could happen all along the SE and Central E coast of FL. I'm not sure how they will determine when the eyewall actually makes landfall-is it the very first place to be "hit"?

P.S. My question may have just been answered as I was writing this

[anjou]

Bump for a good topic