If you haven’t accepted the change you can try to make a case for a voucher by calling American even though officially they try to push the change option.

While an outright cancellation is more clear-cut and a refund is not due purely by virtue of a weather advisory being issued (unless your first segment is significantly delayed or cancelled), a trip that can’t be completed at later date could still be exchanged for a fee-free voucher.

Even without a cancellation in advance, a refund related to a weather event travel advisory wasn't an issue personally back in the pure Saber days but that sounds like it was more an exception to official policy.