Sitting here in West Anaheim at 11 AM on a Beautiful Sunny Monday Morning. A bit overcast, but very nice.
As a local, I would love to get some rain for my front lawn (we have limited times when we can water).
But if it rains tomorrow, it will be very light.
Anytime "rain" is in the forecast, I would do the following.
Plan ahead, maybe wear a light jacket with a hood, or get a cheap poncho from a Dollar Store before you come.
Expect it to only rain for a few minutes at a time, so wherever you are in the parks, find an indoor attraction near you, and more than likely, after you are done, it has passed.
Yes, there are a RARE few days that cause rain issues at the parks, including rides that have to close (such as Alice In Wonderland, Mad Tea Party, and even Big Thunder RR (due to safety sensors), and that parades get changed (
Disneyland has a special "Rainy Day Parade" event if the parade route is too wet for safety reasons.
But tomorrow, no worries....
Now, if you want to see a lot of water on Main Street, here is a fun look back... (Yes, I am also known as David Michael).
http://jimhillmedia.com/alumni1/b/david_michael/archive/2004/10/08/1659.aspx