The forecast command is owned by Heathery and the merchant is the character where the weather bug occurred first. I can also provide a screenshot of the yellow text on top of the screen which says something like blgitblg:blgitblg: tlefield:tlefield:tlefield: which seem to be variables.
Thanks. I figured out what it was now.

Is there anything like a manual or FAQ for this game in english that explains the game mechanisms? The only one on GameFAQs seems to be just a very basic walkthrough. I'm curious about what stuff like "FLV", skills, "area points", etc, mean, and I want to be sure that I'm not missing any menus or commands available. Or will the game itself explain it in due time?
No manual is available at present. The translator does have the original game manual and talked about a potential translation of it at one point, but it never happened for some reason. Perhaps I can inquire again if he would still want to do it.
'FLV' is the body's fitness level. Each body can get to a maximum of level 10. Their stats will go up with each level (this is on top of your character's regular level and stats) and their abilities will be unlocked.
Each body also has a skill level for a particular weapon type they are skilled with. This level is fixed and does not change. Later bodies will have higher skill levels. Some special bodies can are skilled with all and can use any weapon effectively.
The area points are a running stat like the kill count, bad actions etc. I don't think the effect the game in any way that I recall. for how much of the overworld you've covered. Why they decided to do it in point form like that doesn't make much sense to me.