In Los Angeles the best is at the local ABC Channel 7 weather page.

http://abclocal.go.com/kabc/weather/...pler_s_la.html

It give the closest detail but it does not allow zooming the way that it is
done on the air.

Is there a site that has local doppler radar maps that can be zoomed in for
detail .. like Mapquest does with street grids?

Thanks, Lar