[gfunk84]

Is there any way to search on the email server in the Mail app? You can do this on Windows Phone and it works great, but I can't find the option in the Windows 8 Mail app.

[cedarlog]

do you mean search for emails inside the app if so open mail app then go to charm bar click search then seach for specific email
other than that i have no idea

[gfunk84]

I mean searching for a message that isn't locally synced. For example, my client is set to sync the last 2 weeks, but if I'm looking for a message from 2 years ago, I'd like to search on the email server and then download/view that message. This is a feature that works on the Windows Phone 7 Mail app, but I can't find it on the Windows 8 Mail app. It makes the app fairly useless unless you want to sync your entire email history (I don't really need to store 5 GB/ 8 years of email locally).

[cedarlog]

I mean searching for a message that isn't locally synced. For example, my client is set to sync the last 2 weeks, but if I'm looking for a message from 2 years ago, I'd like to search on the email server and then download/view that message. This is a feature that works on the Windows Phone 7 Mail app, but I can't find it on the Windows 8 Mail app. It makes the app fairly useless unless you want to sync your entire email history (I don't really need to store 5 GB/ 8 years of email locally).

then no it doesn't have that option
your only option is to select download last 3 days - last 7 days - last 2 weeks - last month - any time
mail app at the moment have basic functionality