If you want to sync things up, consider using Rex Weather Force then set P2A to import weather from the Rex engine. P2A has a ck box for this. Rex will inject weather directly into the sim so now both are in sync.
Dave from P2A recommends building your flight plan in Simbreif then importing the plan into P2A and then into the plane you are flying. If there is no direct import to the plane, then just enter it manually.
Your flight plan and weather will remain in sync.