Arcane Storms

Arcane storms are varied and dangerous phenomena that happen on Belthuran and can be the result of many things, the flow of magic through the world might pool up in an area and then latch onto a storm front passing through, or the result of a rampant spell detonation, or any number of other causes. Unlike normal storms that can be predicted by anyone with the knowledge, most people will never know an Arcane storm is coming. Magic users are the only ones who have some form of early warning usually in the form of a distant droning or buzzing sound that varies in intensity as the storm grows in strength. Many attempts have been made over the centuries to devise an early warning system or a means to dissipate an Arcane Storm but so far the only ones who have had success are the Draz Tyran, unfortunately, that knowledge has since been lost after the collapse of their old empire and the near extinction of their species at the hands of the dragon hunters in the Dark Age. The only places that can diffuse an Arcane Storm are Xoln, Valtoris'Nemal's flight, Mordereth, and any area within 10 miles of the Obelisks of Creation, which are hidden from sight even to most dragons. Xoln and Valtoris'Nemal's flight both have a means that siphon off the energy of the storm and spread it out across the city to fortify enchantments throughout the city and lair. Mordereth having a high concentration of dragons keeps the arcane flowing through there in a very stable way and while it is possible for an Arcane storm to form as a result of a mishap they do not occur naturally.

Unless otherwise noted Arcane Storms last 2d4-1 hours and cover 3d6 square miles can travel 1/8th of their wind speed per hour, less than 1mph is stationary unless otherwise noted.
When casting a spell within an Arcane Storm there is a 50% chance of increasing or decreasing the level the spell is cast at by 1d4, use a percentile die, or flip a coin to determine this. If the spell goes below 0 it is lost, if the spell goes above 9 consider it affected by the empower metamagic.
Random Precipitation table

1-10	Rain
11-20	Snow
21-30	Sleet
31-40	Hail
41-50	Stones
51-60	Small animals
61-70	Bones
71-80	Blood
81-90	Feathers
91-100	Reverse precipitation

Rain, snow, sleet, or hail are as normal.
Stones: Small rocks pummel the ground,d eating 1 point of nonlethal damage per minute to each creature caught in the open.
Small animals: Snails, crabs, rats, and o the small creatures fall from the air, upon hitting the ground they split open and rapidly decay creating a horrid stench that deals 1d4 points of strength damage to every creature in the area that fails a Consitution or Fortitude saving through DC 15. Furthermore, the slime and blood from the creatures creates difficult terrain in the area. Once the storm ends any affected ability scores are returned to normal and the remains of the creatures dissipate.
Bones: Humanoid bones tumble from the sky forming small piles that assemble themselves into skeletons, animate, and attack. Each minute that this effect continues there is a 25% chance that 1d4 skeletons attack any creature in the area. This cannot happen in areas that are hallowed nor can the skeletons enter such areas without instantly bursting into flames and being destroyed. (No players don't get experience from this unless it was their hallow spell that destroys the skeletons.) Once the storm passes the skeletons fall to pieces where they stood.
Blood: Blood falls from the sky like rain staining the land a crimson red. Every creature caught in this rain must succeed in a DC 15 Constitution or Fortitude save or be sickened or nauseated for 1d4 rounds.
Feathers: A great, dense cloud of feathers fills the air, hindering sight, and muffling sounds. The feathers impose disadvantage or -5 on perception checks in the storm's area. Visibility is reduced to 5 feet, and all targets within that range have half concealment.
Reverse precipitation: Water rises from puddles, lakes, and or rivers and snow soars into the sky leaving the ground bare and clear.

Example Arcane Storms

Firestorm

Mundane effects: Strong or faster winds, 'hail' in the form of chunks of coal, dust storms, windstorms, and tornadoes.
Thick red clouds filled with the seething power of elemental fire move through the sky filled with thunderous explosions that echo out across the land. As the storm moves over an area it deposits a rain of ashes, while also causing the temperature to rise above 100 degrees vaporizing light snow and small puddles or sources of water within 10 minutes. Spells or spell-like abilities with fire damage or the fire descriptor are considered to be empowered via the empower metamagic. Creatures with the Fire subtype gain temporary hit points equal to their hit dice and any saves made to avoid catching fire or to put out a fire is at disadvantage.

Murderous Heat

Mundane effects: light wind, searing heat, and high humidity.
A subtle but dangerous storm is a mix of a hot and humid weather system and darker emotions that permeate an area from past conflicts. It wears against the will of its victims transforming them into murderous psychopaths over the course of a few days. Creatures exposed to the heat slowly become more irritable and ill-tempered. Eventually, this turns into a seething rage that explodes into violence. A simple jest or being bumped into on accident that might be normally ignored now sparks a fight.
This storm lasts for 2d4+1 days for each day it persists every creature within its area must attempt a Wisdom or Will saving throw of 10+ the number of days exposed. Failure means that the creature will respond with violence to the next stressful situation or conflict of any sort. A merchant might attack a customer for trying to barter, a guard might beat someone senseless for the smallest infraction. These bouts of violence last 2d6 rounds before the creature comes back to their senses. This is a mind-affecting enchantment effect.

Ice storm

Mundane effects: Strong or faster winds, a thick freezing fog (if in Ursand it is Gravefog instead), freezing temperatures, blizzards.
Heralding the approach of the storm heavy freezing fog rolls in mere moments ahead of the storm dropping the temperature to below freezing in minutes followed by thick dark grey clouds that hang high in the sky coating the land beneath them in heavy snowfall mixing with the strong winds to create blizzard conditions. Water sources freeze over within 10 minutes under the unrelenting cold of the storm. Spells or spell-like abilities that deal cold damage or have the cold descriptor are considered empowered as per empower metamagic. Creatures with the cold subtype gain temporary hit points equal to their hit dice. Open non-magical fires are extinguished within the area of the storm, and the snow and ice build-up makes for difficult terrain. The whiteout conditions impose disadvantage or -5 on perception checks in the storm's area. Visibility is reduced to 5 feet, and all targets within that range have half concealment. If this storm occurs in Ursand replace the fog with Gravefog.

Hellstorm

Mundane effects: Howling winds that carry the laughter and shrieks of otherworldly nature, supposedly souls from hell screaming. Rain, hail, Tornadoes
Blacked clouds gather and transform the sun's light turning it into a rust-red hue that bathes the land below. The winds carry the thick stench of brimstone and sulfur to replace all other scents as the heat reaches over 100 degrees even in the coldest winter. Water simmers in the presence of the storm causing 1d4 damage to aquatic life per hour of the storm. Each hour the storm lasts there is a 25% chance groups of imps and lesser devils can appear but for only as long as the storm remains, these encounters should be level appropriate but can occur in multiple places at once, one check for each district is one option that you can take or one check for a city.

Heavenstorm

Mundane effects: Light wind, bright sunny day with small amounts of rain clouds that disperse a refreshing rain over the area complete with rainbows.
A Heavenstorm is hard to identify simply because they are not what most people would consider bad, appearing as what most would consider a beautiful day the only way to really tell that it is not so is the fact that a Heavenstorm's sun is actually a mote of celestial energy, there is actually a thick cloud coverage above it and what people are seeing is simply a by-product of the energy mote. This means that for the duration of the storm regardless of the time of day it will appear to be a bright sunny day with light rain and comforting breeze. Those exposed to the light and rain of the storm will feel renewed energy and life flow through them, the sick and infirm will feel markedly better and can even be cured of some ailments.
Good aligned creatures who spend at least 1 hour in the storm's area gain a quarter of their total hp rounded down as temporary hit points. For every hour the storm lasts plants will grow as if a week had passed. Creatures who were suffering from sickened, poisoned, or diseased conditions are cured unless the effect is related to a plot point or from a particularly powerful evil source. Creatures with weakness or sensitivity to daylight are affected by the storm as if it were the sun but only if they are exposed to the light.

Plague storm

Mundane effects: Any kind of wind, light breeze to a hurricane. These storms are difficult to detect with some possible signs being a green haze or the smell of rot on the air, they are often much more subtle as The Blightbringer would prefer their plagues to go mostly unknown until it is too late. This storm lasts 2d6+1 days. Select a disease that the storm carries and each day a creature is exposed to the area of the storm they must make a Consitution or Fortitude saving throw against the given DC with a bonus +2 as the disease is diffused.

Malaise

Mundane effects: Any (seasonal precipitation)
These types of storms are the least showy but are nonetheless dangerous perhaps more so because they can go unnoticed for days. This type of storm can last for days even weeks. Once one starts nothing happens until 24 hours after the storm has formed the first effect of the storm is that all creatures within the area of the storm have terrible nightmares that are forgotten upon waking up that disrupts their sleep unless they sleep inside of an area such as a magical circle or use a dream catcher (yes, even simple ones work so long as the user thinks they do) After that first night the creatures in the area become absentminded and forgetful their work becoming sloppy or even incompetent. Each day after waking up the creature must make a medium (15) Wisdom or will saving throw or they do not benefit from their proficiency bonuses for the day, this does not count for the next day's save. This portion of the storm lasts 1d4 days.
For the following 1d4 days, the effects become more pronounced and the consequences of the populace suffering from the Malaise become more and more apparent, however, the storm does not inflict any other conditions.
The storm reaches its peak 2d6 days after it's creation, once it does reach its peak the populace will find it hard to get anything done at all, low-level creatures and NPCs are likely to fall into a catatonic slumber, those immune to sleep effects are simply lethargic and have a hard time concentrating on a task long enough to achieve it. Any creature not put sleep must make a Wisdom or Will save off 15 or suffer from a massive headache which gives disadvantage (Or a -5) on all wisdom, intelligence, and charisma based skills and checks. Spellcasters run into another problem in that they must make a concentration check of 15 to even cast a spell, failure interrupts them before they get far enough into the process to waste the spell. This persists for 1d4 days.
After the storm's peak has passed it begins to weaken rapidly and all trace of it will be gone by the end of the day. Roll 2d12 for the number of hours the storm persists. Until it ends all creatures in the area have a headache that makes them miserable but able to function.

Stages of Malaise

Creation: 24 hours before initial nightmares.
Phase 1: DC 15 wisdom or will save to retain proficiency bonuses and or training bonuses. Bonuses are available again before trying for the next day. 1d4 days.
Phase 2: 1d4 days of phase 1.
Phase 3: Peak once per day DC 15 Wisdom or Will save of 15 or suffer a headache that imposes disadvantage or -5 on all wisdom intelligence and charisma based skills and checks. Spellcasting becomes more difficult. 1d4 days. NPC's below a CR of 2 should be considered catatonic without needing to roll for an entire settlement. Only important NPCs and players should make a save. Any monsters that should be encountered should have a roll made for them to determine their status.
Phase 4: End, the storm will end all effects within 2d12 hours of midnight. All creatures have a headache that makes them miserable but functional.
After the initial day of creation of the storm roll 2d6 for when the peak occurs and write it down, then roll the 1d4 for how long the peak will last, keep this number separate but also written down. Then roll for Phase 1, once those days have passed roll for Phase 2. Phase 1 or 2 can run into phase 3 to create overlap but neither can exceed the maximum time of Phase 3.
Example: Peak roll 1+1= 2 days till the peak, 3 days until the end of phase 3. Phase 1 rolls a 4, halfway through phase 1 the peak will hit and apply its own effects as well, The DM chooses either Phase 1 or Phase 3's effects to be rolled against by players and important NPCs, but only one of them. Two days later Phase 1 ends so roll for Phase 2 it gets a 4, it cannot last longer than the maximum time of Phase 3 and becomes only the remain time left of 1 day.