Before telling you how to get there, I shall let you know that the owners of weather.com aren't happy with the idea of scripts reading their pages. If you look at their images URLs you'll notice they include the following string:
(I personally have tried to check what this XML is all about with no luck).
To get the real page open a socket to www[/i].w3.weather.com and send the following headers:
- GET /weather/local/55401 HTTP/1.0
Host: www[/i].w3.weather.com
Connection: Close
Anyway, if you're going to make a weather script for constant use, I suggest you to seek for alternatives and not to use it against the webmaster's explicit request.