Found this in the EnergyROM thread (which I'm using) but thought I'd pass it along to the rest of the crowd. Took about 20 minutes to do the install but its working perfectly.
Weatherpanel will allow you to keep the HTC weather but add a more detailed app that can be accessed by tapping on the current weather icon in Cookies Home Tab; check the post to see what it looks like.
http://forum.xda-developers.com/showthread.php?t=707229