If you're asking about the weather radar: For the moment, ONLY Active Sky Next is supported. Other weather add ons simply don't provide the data PMDG needs to get a correct weather display.

Other weather add-ons may provide that data in the future, but for now, you'll have to get ASN if you want to enjoy it.

Simply put: Get ASN, it's well worth the money they're asking for it, and not only because of the WX radar.

I agree with KriVa.  I just landed a group flight with ASN and we all had the same weather.  We were all spaced out as intended.  We all experienced the same chop/turb as reported by other pilots via the PIREPS too.  This wasn't my first time getting the same results either.  It's better than AS2012.  

 

Simpy put, if you're not using a weather add-on, you should be.  Why not make it ASN?