Check out Andy's blog below this one for a complete look at the weekend's forecast. Not much has changed since he posted, and the threat for some heavy rain and possible flooding exists for late Sunday into Tuesday. I have a weird feeling that won't pan out, but it's possible so we are going to talk about it nonetheless!
Saturday we'll notice increasing clouds and isolated showers late in the day and into the overnight. Sunday showers will move in from the west, and a few t-storms will be possible. Severe threat (damaging wind, hail, tornadoes) will be low on Sunday, but as moisture continues to feed in, Sunday night and Monday we could be looking at a heavy rain issue. The big questions to answer, which will be impossible to determine exactly right now, are 1)how fast will the system move? and 2)will we get robbed of moisture from storms that develop to our south? The answer to question 2 could very well be YES, since that happens to us a lot. But, there is a definite possibility that we could get prolonged moderate to heavy rain late Sunday night into Monday.
Take-home message is that Mother's Day shouldn't be a total washout, but showers will be around. Late Sunday night into Monday we'll have a better chance for widespread, soaking rain. We should clear out by mid-week, then temps get back to more summer-like levels. Hope you have a wonderful weekend!