This hasn't happened to me before - a flight cancelled, two days before scheduled departure!
No reason was given, but it might be an abundance of caution in regard to the aggressive flash-floody storms which are schedule to traipse through our hood tomorrow. Our flight wasn't until Wednesday afternoon, but perhaps the incoming plane was at risk?
Luckily, if a little inconveniently, the airline was able to reschedule for the following morning, bright and very early. (It took two agitated hours of waiting for a call-back, though.) No compensation for the stress and disrupted plans, though.
Fingers crossed that that one flies!