I tend to suspect a problem on WU's end, but the image you post sure looks like nothing is happening.
I was going to suggest you check the "Log Sent Data", but you already have the log for Historical Uploads checked. Still, WC may not send that as often as the current data, so it might be easier to find an entry for
any/all data sent. Search for "Wunderground" in Console (All Messages). I'm seeing "Historical" data uploading every 10 minutes, yours is probably different.
Of course, it's won't hurt to double-check your password...
Just saw a post, in another thread, by The Dev. There are several suggested steps that might help you.
Re: WeatherCat quits sending data to weather underground His post is the last one, right now...