The first few results should be Clear to give your players a reprieve; Ominous weather only forecasts dangers to come, Dangerous forces players to make choices between pushing on through danger, exhausting themselves, or finding shelter. Storms cut those decisions down to shelter or danger; exhaustion happens regardless. Disasters are acts of god, altering the terrain and the weather itself, and are as unstoppable as... well, a natural disaster.
5. Buzzing, step up
6. Rain, step up
8. Flooding, step up
10. Thunderstorm, step up
12. Thunderstorm, reset
14. Hallucination Fog.
17. Pollenstorm, reset
18. Hallucination Fog, reset
19. Bugstorm, reset
4. Melting, step.
6. Heatwave, step.
8. Sandstorm, step.
9. Windstorm, step.
10. Sandstorm, step.
11. Solid Lightning, reset.
12. Spellstorm (Fireball), reset.
4. Smog, step.
6. Smog, step.
8. Artillery Barrage (as Micrometeor Storm), step.
9. Bloodstorm, step.
10. Dimensional Rifts (Ground, enemy army's mages), step.
11. Bloodstorm, reset.
12. Spellstorm (any combat spell), reset.
5. Gleaming, step up
6. Dry Lightning, step up
8. Gales, step up
10. Gravity Flux, step up
12. Spellbirth, reset
14. Solid Lightning
16. Dimensional Rifts (sky)
17. Spellstorm (Raise Dead), reset
18. Spellstorm (Cloudkill), reset
19. Cityfication, reset
This doesn't do anything directly to the party, but forecasts further dangers.
2. Cloudy. Forecasts storms of all kinds. The color may give hints to the storms' nature - greyscale for rain or snow, red for blood, black for ash, octarine for spells.
3. Dusty. The grit works its way into your mouth, your nose, your eyes, your pockets. Forecasts sandstorms, ashfall, gale winds.
4. Foggy. You can't see the landmarks, just the road beneath your feet and your companions at your side. Forecasts rainstorms, pollen storms, hallucinatory fog.
5. Freezing. It's really cold out. Forecasts blizzards, hailstorms, solid lightning.
6. Gleaming. The stars twinkle even through the bright day sky. Their light glitters off metal and scatters shadows like shards of glass. Forecasts meteors, or temporal/dimensional shenanigans.
7. Melting. It's really hot out. Forecasts heat waves, ashstorms, spellstorms.
8. Winds. Hold onto your hats. Forecasts gales, vaccuum, sky-rifts.
1. Dry Lightning. Each turn, if you don't take a level of exhaustion, choose to either ground yourself and take 1 damage or roll 1d20 and get hit by lightning (4d6 damage) from a rainless sky on a 1.
2. Flooding. Exhaustion is mandatory through waterlogged terrain. Lowland will be impassable or underwater. Swim!
3. Gales. Save or d4 light items that aren't tied down blown away.
4. Hail. Save or take d4 damage.
5. Heatwave. Save or take d4 damage. Counts as 2 inventory slots.
6. Rain. Save or become waterlogged. On fail, water in your clothes and shoes and bag takes up 2 inventory slots until you get dry.
7. Rumbling. Move at half speed. If you want to move at full speed, save or fall - movement canceled.
8. Sand. Save or blinded in sand for the turn. New save each turn.
9. Smog. Choked by thick pollutant smog. d4 damage, save for half.
10. Snow. Save or chilled. -2 max health (minimum 1) until you return to warmth.
1. Ashstorm. Save or fall and be buried in flurries of ash; you'll have to be dug out.
2. Blizzard. Save or frostbitten (as Snow, but lasts after the blizzard ends, until you have warmth to heal in).
3. Bloodstorm. It's like someone murdered a cloud. Gashes in the sky spill salty crimson, slick and sticky and burning with the fire of life. Take double damage in a bloodstorm, but also heal twice as quickly. You can open your own veins and mingle your blood with the sky's; this will mutate you in accordance with the local ecosystem. Once for temporary, twice for permanent.
4. Bugstorm. Save or take d6 damage as they descend upon you. Can choose to fight them off if you fail the save - but you might take more damage engaging them than you would just running. Could be distracted with offerings of food... or corpses. They denude the hex of anything edible.
5. Cityfication. The land morphs and shifts; trees grow into buildings, hills hollow into halls, rocks grow together into cobblestone streets as nature shares in the light of the city. The fauna sell their wares at market; predators take up billy-clubs and stalk their prey through alleyways to accuse them of victimless crimes. Finding your way will be a challenge; you're trapped within this imitation city until either the storm ends or you barter your way out. Each turn, Wisdom save or accidentally violate some strange social custom.
6. Dimensional Rifts (Ground). Replace the random encounter table with a different one until the storm ends.
7. Dimensional Rifts (Sky). Random esoteric weather effect each turn.
8. Gravity Flux. The weight of the world pulls and tugs. Everything wobbles; pebbles float in air, birds fall from trees too heavy too fly. Save or be caught in a flux. Roll a d20: on a 1-10, you're carried 10*that many feet in the air until next turn. On an 11-20, you're flattened into the ground and must beat that result on a Strength test to move under your own power.
9. Hailstorm. Choose to either be chilled (as Snow) or take d4 damage. No save.
10. Hallucination Fog. Every time you roll on the random encounter table, you find 3 results. Only one is real; you'll have to figure out through trial and error. The GM has free reign to describe whatever to the party. Filtration gear or some kind of independent air supply will prevent this, but otherwise you get no save.
11. Micrometeor Storm. The heavens rain stone like water. Take d4 damage if you can't find something to ablate over your head (whatever you picked gets smashed to pieces).
12. Pollenstorm. Blustering, aching, itching, snotting plant-ejecta fills the air. Halve your maximum Health. Each time you pass the save, restore 1 to your maximum health. Once you've returned to your maximum health this way, you're immune to this region's pollen storms.
13. Rain of Crabs. They pinch! They crush! They follow with a horrific malice! The crabs will have your ankles and swarm in your wake. Save or 1 damage, but each time you pass a save, double the damage for next time. You may choose to fail saves.
14. Sandstorm. Each turn, choose to either be blinded or take 1d4 damage. No save.
15. Solid Lightning. Bolts crash down and cast neon illumination across the land - then hang like vast fractal glowsticks in the night. Destroys your shelter, if any. If unsheltered, save or solid lightning spears through you for 2d6 damage. It feels like a live wire, and removing it will deal d6 more if you don't neutralize it first somehow. They dissolve by the next day, or upon exposure to moonlight.
16. Spellbirth. Octarine light spills down from the opening mouths and eyes of spell-clouds. Save or a spell enters your brain; you can cast it if you have magic dice. It leaves once cast. If it sticks around for longer than the day, it'll try to leave - casting itself to deal maximum damage to whoever's brain it occupies. You can choose to fail this save.
17. Spellstorm. A spell's reached vast and worldshaping power. It rolls across the land, discharging at random, gleefully wreaking havoc. The GM rolls a random spell when the storm occurs. Save vs. getting hit by the spell. Starts at 1 die, each subsequent time it hits you it'll hit at 1 die greater than the last. Will also affect the environment.
18. Thunderstorm. Save or become waterlogged as Rain. On a 1, get hit by lightning (4d6 damage).
19. Windstorm. Your ears pop, there's a thunderous bang, the wind rushes at random. Save or choose from the following: deafened, lose an item at random, or thrown away from the party in a direction at random for d4 damage.
20. Worms. Spontaneous generation. Grubs pour from every crack in the earth, every knot in the trees, wriggle from every rotting carcass. They lightlessly seek meat to gestate in. Save or implanted with d20 grubs the size of grains of rice. They'll hatch if you don't dig them out. Can be distracted with corpses or other, larger, warmer creatures. You don't want to know what the grubs hatch into.
1. Micrometeor Storm.
4. Smog. Step up.
5. Micrometeor Storm.
6. Ashstorm. Step up.
8. Heatwave. Step up.
10. Heatwave. Return to previous weather table.
1. Dimensional Rift (Ground), underdark encounter table. Rumbling.
2. Worms. Rumbling.
3. Smog from a burning underground oil reservoir. Rumbling.
4. Dimensional Rift (Ground) underdark encounter table. Rumbling. Step up.
6. Rumbling. Return to previous table.
1. Thunderstorm. Windstorm. Flooding.
2. Thunderstorm. Windstorm. Flooding.
3. Thunderstorm. Windstorm. Flooding.
4. Flooding. The eye of the storm. Step up.
5. Thunderstorm. Flooding.
6. Windstorm. Flooding. Step up.
8. Windstorm. Return to previous table.
1. Rain of Crabs. Return to previous weather table.
2. Spellstorm. Return to previous weather table.
3. Bugstorm. Return to previous weather table.
4. Solid Lightning. Return to previous weather table.
1. Micrometeor Storm.
2. Gravity Flux.
4. Choose one of: Dimensional Rifts (Ground, aliens); Cityfication; Solid Lightning; Bugstorm (alien bugs). Return to previous table.
1. Cowardice; retreat in the face of certain death (especially if others face it in your stead). Frozen in place until the week ends, or until you fight off a random encounter on your own.
2. Greed; but only in the case of hoarding wealth or power from your comrades-in-arms. All your items weigh you down fourfold until the week ends.
3. Leaving Your Friends Behind; letting a comrade die. Yes, including hirelings. Self-sacrifice exempted. Until the end of the week, whenever one of your comrades takes damage, you take half in their stead.
4. Trust; relying on a comrade who let you down, or being failed in a predictable manner by those you really shouldn't have trusted. Until the end of the week, you can't communicate with others.
5. Martyrdom; sacrificing yourself for another. Until the end of the week, your touch drains life (as a melee attack, but heals you for the damage dealt).
6. Forethought; planning for the future beyond the next adventure. Lose one class level for each venture you've invested in until the week ends.
7. Provocation; creating a threat where none exists, turning potential allies into enemies instead. Until the end of the week, you can't deal more than 1 damage with your attacks.
5. Ominous, step up
6. Dangerous, step up
8. Dangerous, step up
10. Storm, step up
12. Storm, reset
17. Storm, reset
18. Storm, reset
19. Storm, reset
4. Ominous, step.
6. Dangerous, step.
8. Storm, step.
9. Storm, step.
10. Storm, step.
11. Storm, reset.
12. Storm, reset.