I have in the past got fabulous weatherfax results using Sony SSB (https://www.amazon.co.uk/Sony-ICFSW7600G-ICF-SW7600GR-World-Radio/dp/B00006IS4X) and using HF Weather Fax app on android tablet - just by using speaker and microphone rather than a line in.Hmm. That's a nice little receiver. Not quite sure if the P or W version would be appropriate EDIT - it's the W version. P doesn't have the direct output.
Linking to a tablet rather than a laptop would be preferred, I think. Though maybe a little netbook might work.
Your comment about the "right message" presumably differentiates between the quality of the forecast document, and that of the weather it predicts ?