Try this. Pour a cup of coffee into your cup tomorrow morning. Do the bubbles go to the edge quickly? If so, you will have clear skies for the next 12 hours. If the bubbles hang out in the middle of the cup, bring your umbrella. If the bubbles slowly migrate to the edge, then there may be weather, but it will clear after a few hours. (From the craftzine article here.)
Here's the theory: high pressure pushes the bubbles to the edge, indicating clear skies. Low pressure doesn't move the bubbles, which means unsettled weather, see this post.
I am definitely having a cup of coffee in the morning!