Not sure where your located but Magnum V8s have had starting problems during wet weather. My '98 SST started acting like yours last year but just on rainy/cold days. I would let it sit for a day then it would start up just fine. I tuned it up last week because it was long overdue and haven't had any issues yet.
I've read that a faulty cold temp sensor or intake air temp sensor can cause it. I tried to remove and clean the IAT sensor a couple weeks ago but my torx driver rounded off. The IAT also gets carboned up and need to be cleaned on occasion. Like every year.....which I try to do.


and check the fuel pump fuse...