You're using the Touch Pro 2 port right? If so, use the new HTC Weather Master 2.2 app located here:
http://forum.xda-developers.com/showthread.php?t=480101
I'm using the HD port so I used the original Weather Master 1.3 app. This is what I did:
1) Disable Touch Flo
2) Install Weather Master on Storage Card (doesn't matter if you do device or storage card - I always try to save on card as often as I can)
3) Soft Reset
4) Go to Windows Directory & delete forecast cache
5) Load Weather Master & add whatever city needed
6) Reload Touch Flo