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Jan,


You are correct, my example is motivated by regional experience. Generally,
low pressure
systems follow a southwest to northeast track across the eastern portion of
the US.
This ,of course, is dictated by the meaderings of the jet stream for we are
in the prevailing
westerlies as part of the Temperate Zone. Regardless, your location
relative to the low dictates
whether the wind will back or veer. For reasons of simplicity, I always
refer to an idealized
south to north path of the low when teaching weather.

Joe Kliment


At 11:17 AM 1/25/03 +0100, you wrote:
>Dear Capt. Joe Kliment,
>
>I don't know, why you use the low travelling from S to N for your
>illustration of the changing direction of wind in a low). Maybe it is
>motivated by your personal or regional experience, but generally these
>lows are rather rare. In textbooks, the low runing from W to E is
>invariantly used for this purpose, with two observers to S (wind turning S
>->SW->W->NW->N)  and N (S->SE->E->NE->N, both cases for the northern
>hemisphere) of its path, as in the most cases, the observers to the E and
>W of the low experience the wind of a steady direction (cca N or S), only
>its strength is changing. Of course, this is only an idealized case, but
>we all use such simplified patterns in this discussion.
>
>As for the theme itself, I skimmed through my scarce texts on meteorology
>in English and I suppose that they use "backing / veering" for northern
>regions, but more general terms (e.g. "shifting / turning" with subsequent
>details) when the southern hemisphere is explicitly meant, so as to avoid
>a misunderstanding. U.S. Sailing directions for Australia (1931 and later)
>provide a clear example.
>
>
>Jan Kalivoda
>
>
>----- Original Message -----
>From: "kliment" 
>To: 
>Sent: Saturday, January 25, 2003 5:08 AM
>Subject: Definition of Term
>
>
> > In the northern hemisphere high pressure systems are associated with
> > clockwise winds(anticyclonic) while low pressure systems are associated
> with
> > counterclockwise winds(cyclonic). This is opposite in the southern
> hemisphere
> > with counterclockwise highs and clockwise lows. Your location
> > with respect to a low will dictate whether the wind will "back" or "veer"
> > as the low passes. In the northern hemisphere if the low passes east of
> > your location the winds will "back" from NE ,N, NW,  to W and if the
> low passes
> > west of your location then winds will "veer" from NE, E, SE, to S.
> >
> > By applying Buys Ballot's Law you can determine the location of the center
> > of the low and
> > predict it's path with either "backing" or "veering" winds.
> >
> > Capt Joe Kliment
> > W3HZM
> > Middletown,De.

   

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