Weighting a rollable table to replicate a nested rollable table.

Ok, I'm not very good at math, and I want to replicate what would be a nested rollable table by incorporating it into one. This is for a weather generator, but it's not really important what it's for, what I want to do is figure out how to weight the items on these tables. So, first you have (for example) a table that is something like this: roll 1d30 1-8 - no precipitation 9-14 - single cell storm (roll on table 1a) 15-20 - multiple cell storm (roll on table 1b) 20-25 - multiple cell line storm (roll 2x on table 1a) 25-30 - Supercell storm (roll 2x on table 1b) Then, you have tables for effects: 1 - .1 inch rain 2 - .3 inches rain 3-4 - .5 inches rain ...etc. I know that I could make this all into one huge table, but I don't know how to weight it correctly. Can someone give me some help in this area?

I think you need to go with the huge table, one cell for every possibility. 1-32 "No Precipitation 33 - Single cell storm (.1' Rain) 34 - Single cell storm (.3' Rain) 35 - Single cell storm (.5' Rain) 36 - Single cell storm (.5' Rain) ... 80 multiple cell storm(.1' rain) 81 multiple cell storm(.3' rain) 82 multiple cell storm(.5' rain) 83 multiple cell storm(.5' rain) ....

Ok, I'm looking at the table again, and some results in the first table are things like "roll 2d6 for the number of cells," and then each cell rolls on the second table for effects. So, if I make an entry for each potential ramification of that, that would get....well, pretty big I think. And then would that not change the weighting? Since there would be so many entries under "multiple cell storm," would that not make the 1-8 roll of "no precipitation" incorrectly weighted?

This is where tables & arrays start to get unwieldy To simulate a 2-dimensionally array for every sub-chance (2nd dimension) you add, you have to also add that many possibilities to the non-entities to preserve probability.. Start with a simple 1,2 or 3 table : (~33% chance to land a "1") 1 2 3 Then add specific sub-chances: (~16% chance to land a "1", which is not what we want) 1 2 ---| A ---| B ---| C 3 To fix it so you preserve an equal chance you end up with: (~33% to land a "1") 1 ---| 1 (blank or same as regular 1) ---| 1 (blank or same as regular 1) ---| 1 (blank or same as regular 1) 2 ---| A (sub-chance of 2) ---| B (sub-chance of 2) ---| C (Sub-chance of 2) 3 ---| 3 (blank or same as regular 3) ---| 3 (blank or same as regular 3) ---| 3 (blank or same as regular 3) So by that, if you have a sub-chance of 2d6 on a 2, you need to add 12(max of 2d6) instances for every other value. (~33% to land a "1") 1 ---| 1 (blank or same as regular 1) ---| 1 (blank or same as regular 1) ... (until there's 12 of them ) 2 ---| A (sub-chance of 2) ---| B (sub-chance of 2) ---| C (Sub-chance of 2) ---| D (sub-chance of 2) ---| E (sub-chance of 2) ... (until there's 2d6max (12) variations) 3 ---| 3 (blank or same as regular 3) ---| 3 (blank or same as regular 3) ... (until there's 12 of them )

Well, actually that helps me conceptualize it a bit better. But for a rollable table I don't need to repeat the "1s" in the above example, but I would need to weight that first example with the correct number, right?

yeah just weight the repeats "1" weight 12 is the same as entering 12 "1"s