Epic weather effect post!

[MrGrendel]

Since (it seems) these aren't implemented yet, I thought I'd go through the pnp list of weather effects and try to compile a hopefully helpful list! Also this is yet another thing that could be affected by a survival skill implementation, so plug plug plug. :o (Successful survival skill checks give you a bonus to your saves vs certain weather effects, and could arguably lessen the penalties of other things as well. Not to mention predicting the weather a day in advance with it!)
 
First of all, here is a comprehensive but simplified weather table from the d20SRD, appropriate for our climate. Detailed effects follow, I faithfully pieced together everything from the various parts of the System Reference Document, omitted anything irrelevant to our setting/mechanics, and went ahead and combined wind effects with the appropriate weather effects, too.
 
Weather Table

• 01-80 Normal for season (No effects)
• 81-90 Precipitation (Typical for season)
• 91-99 Thunderstorm
• 100 Thunderstorm accompanied by a Tornado

And here are the appropriate effects:
 
Precipitation (81-90)

• 01-30 Fog
• 31-100 Rain

Fog
 
Duration 2d4 hours

• 20% miss chance with ranged weapons
• Conceals all sight beyond 5 feet - suggest emulating this with:
• -10 to Spot
• -10 to Search
• 50% miss chance with ranged weapons instead

Rain
 
Duration 2d4 hours

• -4 to Spot
• -4 to Search
• -4 to Listen
• -4 to Ranged weapon attacks (Not sure you can do this in the toolset - suggest emulating this with a 20% ranged miss chance like fog)
• Unprotected flames are extinguished, protected flames have a 50% chance of being extinguished. (Setting campfires)

Thunderstorm (91-99)
 
Duration 2d4-1 hours

• -8 Spot
• -8 Search
• -8 Listen
• Ranged weapon attacks other than siege weapons (-4 AB for these) are impossible: 100% ranged miss chance
• Unprotected flames are extinguished, protected flames have a 50% chance of being extinguished. (Setting campfires)
• In addition to wind and precipitation (usually rain, but sometimes also hail), thunderstorms are accompanied by lightning that can pose a hazard to characters without proper shelter (especially those in metal armor). As a rule of thumb, assume one bolt per minute for a 1-hour period at the center of the storm. Each bolt causes electricity damage equal to 1d10 eight-sided dice.
  
• I would suggest checking merely two things: the terrain type and the armor type worn. Urban and forest tilesets would incur a smaller chance than, say, the plains, mountain or cliff areas. Wearing metal armor would increase the chance of being struck.

Failing a Fort save of 15 DC during a thunderstorm also incurs:

• Tiny creatures are blown away. Moved about 25 feet in a random direction, and take 1d4 d4 of nonlethal damage. Flying creatures are moved about 70 feet and suffer 2d6 nonlethal damage.
  
• Small creatures are knocked down.
• Medium creatures are unable to move forward.
• Large creatures are unaffected.

Thunderstorm accompanied by a Tornado (00)

• Duration 2d4-1 hours

All of the effects for Thunderstorms apply, with the following exceptions:

• All flames are extinguished.
  
• All ranged attacks are impossible, including siege weapons.
  
• If the tornado funnel is in "close proximity," then instead of the previous Wind Effects table, the following rules are used: Failing a fort save of 30 near a Tornado incurs:
• Large creatures and smaller are sucked towards the tornado funnel. Those who come in contact with the actual funnel cloud are picked up and whirled around for 1d10 rounds, taking 6d6 points of damage per round, before being violently expelled (falling damage may apply). "Loading: Tornado Funnel," anyone? Muahaha...
  
• Huge creatures are knocked down.
• Gargantuan or Colossal creatures are unable to move forward.

[Hammerfist0]

Obviously, these would need to be modified heavily. But:

Please make weather have effects, it would be epic.

[MrGrendel]

Woops, overlooked this.
 
"Tornadoes are very short-lived (1d6×10 minutes)." (And of course they would be localized, not all over. Wonder if you could actually make a Tornado NPC... heh.)
 
Also, I omitted Hurricanes, since it's just a step inbetween thunderstorms and thunderstorm/hurricane. Figured it's not really adding anything new, just a more severe thunderstorm without the risk of a hurricane and more buffeting characters around in the wind.
 
What exactly about these effects would you change, Hammerfist? I think it could be put in just as posted here, but am curious what you're thinking.

[Letsplayforfun]

I don't know how far you can go in building weathers, but that would be awesome. There already was that pouring rain reducing visibility to naught that was quite cool; more would be fun.

[adharmas]

I guess you haven't encountered the fog that turns people inside out?

[dragonfire9000]

Do you guys have ANY idea how amazingly... well, I hesitate to say it, but UBER this would be if it was implemented? I mean, running into a Tornado out in the middle of the Sloping Path, or up in the Mistys... *shiver* It makes my blood boil, so it does!

However, I need to hear from a DM quickly, before my hopes grow to heights from which concussion results when dropped.

[MrGrendel]

Ah ha. To make sure that the results would not be weighted heavily in favor of rain, you would apparently have to have a duration for the "normal weather as well. 2d4 hours of clear weather per roll should keep the ratio of clear:rain approximately as the table intended.
 
 
Also, there's nothing to say that fog couldn't accompany rain as an unusually heavy downpour.

[djspectre]

considering the island would be buffeted from typhoons, hurricanes and tsunami's, I would think things like insane wind (typhoon), insane wind and rain (hurricane) and Tsunami's (insane water/flooding) are doable.

Anything with wind would create a movement penalty and should reduce, but not eliminate attacks with ranged weapons. I mean you aren't likely to hit your target in high wind, but you still might.

The rain/water based ones should create flooding, which if lasted long enough, should flood tombs and under ground caves, forcing you to evacuate.

All in all I think that a weather system that had impacting effects on people would be extremely complicated and difficult to implement.

[MrGrendel]

Anything with wind would create a movement penalty and should reduce, but not eliminate attacks with ranged weapons. I mean you aren't likely to hit your target in high wind, but you still might.

You might hit your buddy, too. ;)