NW Sisu

Hey, I am brand new here on this forum, this is my first post. I am not a "pro" climber, but I do climb Mt St Helens mostly once a year. I will climb it this coming Monday, and I was hoping to head up early enough to watch the sunrise. Not from the top, but from somewhere above the treeline, if possible. Now the forecast is overcast for Monday morning, does anyone know how high I need to climb to get above the clouds? I do have a feeling I might have to forget about seeing any sunrise on this climb, due to the weather . I won't be able to head out at midnight, I was thinking maybe about 4am.