Realistic Weather Patterns [Archive] - Wizards Community

Realistic Weather Patterns [Archive] - Wizards Community

Post/Author/DateTime Post
Johnny_Angel
05-26-07, 10:51 PM I realize that D&D is a fantasy game, and that --as a world builder/DM-- I don't need to go into extreme detail and extreme accuracy when it comes to weather, currents, and things of that nature in a campaign world, but I think it would be nice to at least have some semblance of a realistic planet. Unfortunately, when it comes to eco-systems, weather patterns, currents, and things of that nature, I'm not very knowledgable. I do have the basic knowledge about things work in our world (i.e. rivers flow down hill, high mountains can block weather, and etc,) but I don't have enough knowledge about how things work to take those concepts and apply them to a fictional world.

Right now I am in the process of drawing the map of the world in a new campaign world I am working on. The current continent I am working on is roughly the size of Australia, and -if my world was compared to Earth- it would be located somewhere around where the states of Pennsylvania, Ohio, and New York are in the United States.

My assumption is that the weather would be similar to the weather in those areas: temperate; have roughly an equal amount of all four season. However, I'm not sure if the fact that the continent I'm building is shaped more like a large island (like Australia) instead of part of a continent (like where Pennsylvania is) would have an impact on the weather. Another fact about the continent I am working on is that a good portion of the coast of the whole continent -yes, all the way around- is mountainous. There are plenty of rivers and lakes though, so there's enough water (I think) for it to not be a dry area due to the mountains.

Does anyone know enough about this sort of thing to give me an opinion one way or the other?

Also, if possible, I'd like some people who are more knowledgable about this sort of thing to chime in and give me a few pointers about how weather patterns work. I don't need to know enough to get an extreme amount of accuracy, but I would like at least enough knowledge (as I said before) to at least be able to create some sense of realism.
Darth Syntax
05-27-07, 01:51 AM Without seeing the map in detail, I can only provide very general ideas about climate and such.

As you are going to have a large number of coastal mountains, the interior is going to be very dry indeed (Australia, which you mentioned is, overall, the driest continent on earth), however it may not be a total desert, depending on the height of the mountains. Moreover, if the interior of the continent is a plateau then it has the potential to be both cool or cold and dry. It's not going to be a lush interior, but the coasts might well be dominated by temperate rain forests given that so much water will be dumped their by the clouds.

The complete ring of mountains is rather improbable, it is more likely that there would be several different ranges that effectively block much of the interior, but there are sure to be gaps and the like.

Also, it might be a good idea to consider how much oceanic coverage your world has. The larger the oceans, the greater the force of the storms that will develop there.

Hopefully some of this will be helpful and if you can post a map, that would be great.
OleOneEye
05-27-07, 01:51 AM Winds typically blow from the west to the east in the northern temperate zone. As air masses move over the ocean, it picks up water through condensation. Hitting the west coast, the air mass will rise up the mountains. As the air rises, it will cool. The cooler that air becomes, the less moisture that it will hold, thus producing rain. The west coast will therefore have lots of rainfall - making lush forests. As the air moves across the coastal mountains into the interior, it descends and warms. As much of the water in the air has already fallen on the coast, and warmer air can hold more water, there will be little rain within the interior making it quite arid - grasslands or desert.
Johnny_Angel
05-27-07, 02:52 AM Without seeing the map in detail, I can only provide very general ideas about climate and such.

As you are going to have a large number of coastal mountains, the interior is going to be very dry indeed (Australia, which you mentioned is, overall, the driest continent on earth), however it may not be a total desert, depending on the height of the mountains. Moreover, if the interior of the continent is a plateau then it has the potential to be both cool or cold and dry. It's not going to be a lush interior, but the coasts might well be dominated by temperate rain forests given that so much water will be dumped their by the clouds.

The complete ring of mountains is rather improbable, it is more likely that there would be several different ranges that effectively block much of the interior, but there are sure to be gaps and the like.

Also, it might be a good idea to consider how much oceanic coverage your world has. The larger the oceans, the greater the force of the storms that will develop there.

Hopefully some of this will be helpful and if you can post a map, that would be great.

I'm trying to find a viable way to post my map... it's too big for me to scan it.

I think what I might do is use my digital camera to take some pictures of it once I have a more finished product.

I envision that the world will be roughly the same size as Earth, but it might be a little bit bigger once I'm done. There will be continents, but -the way my brain is going right now- I envision there being more continents than on Earth, but with the continents being smaller than Earth's continents.

I appreciate the help. I know I didn't provide a whole lot of detailed information, but that's because I don't have many of the details fleshed out yet.
Darth Syntax
05-27-07, 03:35 AM It's understandable that you don't have the whole thing worked out yet, it happens believe me. As for getting something put up, even a quick sketch in something like paint would be helpful in getting a better feel for what your landmass is shaped like.

Good luck with the map.
Araes
05-27-07, 04:16 AM Some other issues that can have an impact on the weather patterns over your continent, which were somewhat mentioned by DS, are the ways in which the oceans are laid out around your continents. If you tend to have large sections of north-south waterflow, and not too much open expanse of west-east flow, then you will generally have more uniform climate conditions. Conversely, the opposite will on average produce a more turbulent atmosphere.

The design you have suggested of having a similar percentage of landmass, but divided into smaller continents is in general also going to produce a more mild climate than Earth's if they are fairly evenly distributed. Big sections of flat land are a major source of air currents, as they heat more easily than large bodies of water, since most of the sun's heat becomes concentrated in a thin layer of solid material near the surface.

I generally was under the impression that large bodies of water are only responsible for storms if they are also fairly stagnant and subject to regular heating (the Gulf of Mexico for example).

I agree in the general sense that the interior of your landmass is probably going to be fairly arid. Lakes and other large watermasses might have a hard time forming in the first place unless there is a gap, or there was a significant body of water (like a large inland ocean) that became trapped.

One potential reason for the massive ring of mountains could be an old, gargantuan meteor hit. That would put up a massive ring of land around the center, and over time might come to look simply like mountains. Such a big hit though might have caused problems for any life which existed at the time.
Johnny_Angel
05-27-07, 04:24 AM There is a rather large lake which is roughly centered on the continent.

I'm not sure if it's realistic, but there are 3 rivers which flow from the various mountains into the lake; there's a 4th river which runs from the lake into the ocean...there are less mountains on the souther part of the continent.

I'm having a hard time putting a picture up. I'm assuming I need to upload my picture to a website somewhere, so is there a good website at which I can store pictures? If so, what site?
Araes
05-27-07, 04:29 AM Flickr is a common repository for this kind of stuff that allows moderate linking and usage. Google Pages are also another culprit that don't care much about bandwidth.

If there is a massive central lake, then there might be reason for the rivers running back into the lake, as the arid wind currents would pick up moisture off the big lake / ocean, and then drop it when they hit the eastern mountains.

*edit* Oh, and look over Creating an Earthlike Planet (http://www.compulink.co.uk/~morven/worldkit/index.html)for a really crunch heavy analsis of things like planetary tilt and global weather patterns.
Johnny_Angel
05-27-07, 04:38 AM http://www.flickr.com/photos/8516524@N03/515787451/

Some things to keep in mind:

I'm not very skilled at using paint to draw.

This is my first draft, so it's a bit rough.

I had to draw a lot of it from memory because I seem to have misplaced the sketch I had on paper. I'm sure it's here somewhere, but it's somewhere among the stack of papers I have here.

Anyway, this should at least give you a pretty rough idea of what the continent looks like.
Johnny_Angel
05-27-07, 04:40 AM I can't seem to get the picture to work by linking it, so try just clicking on this link

http://www.flickr.com/photos/8516524@N03/515787451/
Araes
05-27-07, 05:00 AM I would generally say that the west to east rivers on the left side of the map seem a little bit sketchy, and the forrest in the upper right would also most likely not exist unless this were a southern continent. In fact, this whole setup would actually work much better as a southern land, and you might consider mirroring the whole thing to use it as a northern one.
Johnny_Angel
05-27-07, 05:08 AM So should I -for a lack of better words- flip it upside down?
OleOneEye
05-27-07, 05:55 AM (I don't any formal climatology training nor know if weather patterns make a difference whether in the northern or southern hemispheres. That said, I see no reason to flip it upside down nor mirror image it.)

The west coast will likely have lush rain forests.

The most arid portion will likely be on the eastern side of the western mountains. The river just west of the rolling hills may be seasonal.

Forests in the southeastern portion of the continent make me think that an air current flows up from the southern ocean - much like that coming form the Gulf of Mexico over the southeastern US. Converging weather systems could very well hit in the area between the two mountain chains - making that the most likely place for tornadoes. Lots of low-lying swampy coastlines in the southeastern portion would seem to fit.

I can think of no reason why the northern half of the continent would be arid, so placement of rivers would seem appropriate.

Forests dominate any area that receives ample rainfall. Grasslands/deserts typically only occur where rainfall is rather scarse, hence place more forests. Though, they may have mostly been cut down by whatever civilization there may be or destroyed by various evils.

The northeastern forest is somewhat hard to justify as your color scheme makes it appear the most lush on the continent. It would likely be thin and patchy, though magic can certainly be at play.

The western mountains surely are the border of two plates pushing into each other. Make sure to place some volcanoes and earthquakes could be quite common. Maybe get a picture of the Andes mountains to show the players what they may look like.

The eastern mountains may be a triangular plate smashing into the main continent's plate. Its point is the northeastern forest, the bulk of which lies in the ocean. Volcanoes and earthquakes here as well. Maybe get a picture of the Alps to show the players what they may look like.

The small northern mountains may look something like the Appalachians, old and weathered, unlikely to have volcanoes or much seismic activity.

Be sure to place some islands scattered around the continent - perhaps trailing off the northern and southern tips of the western mountains and off the two spurs of the eastern mountains as they reach the ocean.

Most of the waters for the southern half of the continent dumps into the ocean from the one river that drains the lake. It would be prone to flooding and have a healthy delta.
Araes
05-27-07, 03:40 PM In my comment I was suggesting a west to east mirroring, not a north to south. My reasoning for this was that all of the areas on the map would then work with almost no tweaking.

The forest in the bottom right would now be on the windward side of all the mountains, and would be in a high rainfall area, which would make perfect sense.

The lake would also be in a massive rainfall zone, and would have naturally formed.

The forest in the upper right would very logically be a rainforest, because it is in a tiny area with huge walls of mountains behind it forcing all the northern rain to drop right there.

The rivers on the upper right would also be more likely if they were on the windward side of the continent, as now the mountain range they are spawning from would be a west-east chain primarily, which wouldn't stop nearly so much rain on the windward side near the ocean.

Here's a general picture of how I think it should work.

http://araesmojo.googlepages.com/AutraliaLikeContinent.jpg
Johnny_Angel
05-27-07, 08:44 PM Thanks for the picture Araes.

Instead of flipping everything around, could I just remove some of the mountains from the west and add more to the east? (which would also save me from having to redraw a lot)

I edited the picture, and I posted a second version to better illustrate what I mean: http://www.flickr.com/photos/8516524@N03/516982543/

http://www.flickr.com/photos/8516524@N03/516982543/

I was thinking that the northern part of the continent would probably be pretty dry, but I'm not sure.

Also, I'm not sure if this matters, but I plan to have an island similar in size to Japan somewhere around this continent. If you can picture what Japan looks like and then rotate it so that it would be horizontal in relation to how a map is positioned. I was thinking about putting it south of this continent; roughly the same distance that Cuba is from the United States. I'm not sure if that would have any sort of noticable impact on the main continent or not.
Araes
05-27-07, 09:07 PM Overall I think the second map you have on flickr works pretty well. I'm not sure about that river coming from the upper left, but its not a big deal.

I don't think that having an island the size of japan to the south of the continent would have a major effect, but this would depend on what the general oceans are like all around the continent. Generally, how much effect does Cuba really have on N. America vs the larger effects of the Atlantic stream and the Gulf of Mexico?
Johnny_Angel
05-28-07, 02:10 PM Do you think it would be more believable without the river on the left?
Araes
05-28-07, 08:51 PM I personally don't think its that big of a deal. Its a little unlikely, but not implausible. I think that for the most part the continent is fine as is.

Post/Author/DateTime	Post
Johnny_Angel 05-26-07, 10:51 PM	I realize that D&D is a fantasy game, and that --as a world builder/DM-- I don't need to go into extreme detail and extreme accuracy when it comes to weather, currents, and things of that nature in a campaign world, but I think it would be nice to at least have some semblance of a realistic planet. Unfortunately, when it comes to eco-systems, weather patterns, currents, and things of that nature, I'm not very knowledgable. I do have the basic knowledge about things work in our world (i.e. rivers flow down hill, high mountains can block weather, and etc,) but I don't have enough knowledge about how things work to take those concepts and apply them to a fictional world. Right now I am in the process of drawing the map of the world in a new campaign world I am working on. The current continent I am working on is roughly the size of Australia, and -if my world was compared to Earth- it would be located somewhere around where the states of Pennsylvania, Ohio, and New York are in the United States. My assumption is that the weather would be similar to the weather in those areas: temperate; have roughly an equal amount of all four season. However, I'm not sure if the fact that the continent I'm building is shaped more like a large island (like Australia) instead of part of a continent (like where Pennsylvania is) would have an impact on the weather. Another fact about the continent I am working on is that a good portion of the coast of the whole continent -yes, all the way around- is mountainous. There are plenty of rivers and lakes though, so there's enough water (I think) for it to not be a dry area due to the mountains. Does anyone know enough about this sort of thing to give me an opinion one way or the other? Also, if possible, I'd like some people who are more knowledgable about this sort of thing to chime in and give me a few pointers about how weather patterns work. I don't need to know enough to get an extreme amount of accuracy, but I would like at least enough knowledge (as I said before) to at least be able to create some sense of realism.
Darth Syntax 05-27-07, 01:51 AM	Without seeing the map in detail, I can only provide very general ideas about climate and such. As you are going to have a large number of coastal mountains, the interior is going to be very dry indeed (Australia, which you mentioned is, overall, the driest continent on earth), however it may not be a total desert, depending on the height of the mountains. Moreover, if the interior of the continent is a plateau then it has the potential to be both cool or cold and dry. It's not going to be a lush interior, but the coasts might well be dominated by temperate rain forests given that so much water will be dumped their by the clouds. The complete ring of mountains is rather improbable, it is more likely that there would be several different ranges that effectively block much of the interior, but there are sure to be gaps and the like. Also, it might be a good idea to consider how much oceanic coverage your world has. The larger the oceans, the greater the force of the storms that will develop there. Hopefully some of this will be helpful and if you can post a map, that would be great.
OleOneEye 05-27-07, 01:51 AM	Winds typically blow from the west to the east in the northern temperate zone. As air masses move over the ocean, it picks up water through condensation. Hitting the west coast, the air mass will rise up the mountains. As the air rises, it will cool. The cooler that air becomes, the less moisture that it will hold, thus producing rain. The west coast will therefore have lots of rainfall - making lush forests. As the air moves across the coastal mountains into the interior, it descends and warms. As much of the water in the air has already fallen on the coast, and warmer air can hold more water, there will be little rain within the interior making it quite arid - grasslands or desert.
Johnny_Angel 05-27-07, 02:52 AM	Without seeing the map in detail, I can only provide very general ideas about climate and such. As you are going to have a large number of coastal mountains, the interior is going to be very dry indeed (Australia, which you mentioned is, overall, the driest continent on earth), however it may not be a total desert, depending on the height of the mountains. Moreover, if the interior of the continent is a plateau then it has the potential to be both cool or cold and dry. It's not going to be a lush interior, but the coasts might well be dominated by temperate rain forests given that so much water will be dumped their by the clouds. The complete ring of mountains is rather improbable, it is more likely that there would be several different ranges that effectively block much of the interior, but there are sure to be gaps and the like. Also, it might be a good idea to consider how much oceanic coverage your world has. The larger the oceans, the greater the force of the storms that will develop there. Hopefully some of this will be helpful and if you can post a map, that would be great. I'm trying to find a viable way to post my map... it's too big for me to scan it. I think what I might do is use my digital camera to take some pictures of it once I have a more finished product. I envision that the world will be roughly the same size as Earth, but it might be a little bit bigger once I'm done. There will be continents, but -the way my brain is going right now- I envision there being more continents than on Earth, but with the continents being smaller than Earth's continents. I appreciate the help. I know I didn't provide a whole lot of detailed information, but that's because I don't have many of the details fleshed out yet.
Darth Syntax 05-27-07, 03:35 AM	It's understandable that you don't have the whole thing worked out yet, it happens believe me. As for getting something put up, even a quick sketch in something like paint would be helpful in getting a better feel for what your landmass is shaped like. Good luck with the map.
Araes 05-27-07, 04:16 AM	Some other issues that can have an impact on the weather patterns over your continent, which were somewhat mentioned by DS, are the ways in which the oceans are laid out around your continents. If you tend to have large sections of north-south waterflow, and not too much open expanse of west-east flow, then you will generally have more uniform climate conditions. Conversely, the opposite will on average produce a more turbulent atmosphere. The design you have suggested of having a similar percentage of landmass, but divided into smaller continents is in general also going to produce a more mild climate than Earth's if they are fairly evenly distributed. Big sections of flat land are a major source of air currents, as they heat more easily than large bodies of water, since most of the sun's heat becomes concentrated in a thin layer of solid material near the surface. I generally was under the impression that large bodies of water are only responsible for storms if they are also fairly stagnant and subject to regular heating (the Gulf of Mexico for example). I agree in the general sense that the interior of your landmass is probably going to be fairly arid. Lakes and other large watermasses might have a hard time forming in the first place unless there is a gap, or there was a significant body of water (like a large inland ocean) that became trapped. One potential reason for the massive ring of mountains could be an old, gargantuan meteor hit. That would put up a massive ring of land around the center, and over time might come to look simply like mountains. Such a big hit though might have caused problems for any life which existed at the time.
Johnny_Angel 05-27-07, 04:24 AM	There is a rather large lake which is roughly centered on the continent. I'm not sure if it's realistic, but there are 3 rivers which flow from the various mountains into the lake; there's a 4th river which runs from the lake into the ocean...there are less mountains on the souther part of the continent. I'm having a hard time putting a picture up. I'm assuming I need to upload my picture to a website somewhere, so is there a good website at which I can store pictures? If so, what site?
Araes 05-27-07, 04:29 AM	Flickr is a common repository for this kind of stuff that allows moderate linking and usage. Google Pages are also another culprit that don't care much about bandwidth. If there is a massive central lake, then there might be reason for the rivers running back into the lake, as the arid wind currents would pick up moisture off the big lake / ocean, and then drop it when they hit the eastern mountains. edit Oh, and look over Creating an Earthlike Planet (http://www.compulink.co.uk/~morven/worldkit/index.html)for a really crunch heavy analsis of things like planetary tilt and global weather patterns.
Johnny_Angel 05-27-07, 04:38 AM	http://www.flickr.com/photos/8516524@N03/515787451/ Some things to keep in mind: I'm not very skilled at using paint to draw. This is my first draft, so it's a bit rough. I had to draw a lot of it from memory because I seem to have misplaced the sketch I had on paper. I'm sure it's here somewhere, but it's somewhere among the stack of papers I have here. Anyway, this should at least give you a pretty rough idea of what the continent looks like.
Johnny_Angel 05-27-07, 04:40 AM	I can't seem to get the picture to work by linking it, so try just clicking on this link http://www.flickr.com/photos/8516524@N03/515787451/
Araes 05-27-07, 05:00 AM	I would generally say that the west to east rivers on the left side of the map seem a little bit sketchy, and the forrest in the upper right would also most likely not exist unless this were a southern continent. In fact, this whole setup would actually work much better as a southern land, and you might consider mirroring the whole thing to use it as a northern one.
Johnny_Angel 05-27-07, 05:08 AM	So should I -for a lack of better words- flip it upside down?
OleOneEye 05-27-07, 05:55 AM	(I don't any formal climatology training nor know if weather patterns make a difference whether in the northern or southern hemispheres. That said, I see no reason to flip it upside down nor mirror image it.) The west coast will likely have lush rain forests. The most arid portion will likely be on the eastern side of the western mountains. The river just west of the rolling hills may be seasonal. Forests in the southeastern portion of the continent make me think that an air current flows up from the southern ocean - much like that coming form the Gulf of Mexico over the southeastern US. Converging weather systems could very well hit in the area between the two mountain chains - making that the most likely place for tornadoes. Lots of low-lying swampy coastlines in the southeastern portion would seem to fit. I can think of no reason why the northern half of the continent would be arid, so placement of rivers would seem appropriate. Forests dominate any area that receives ample rainfall. Grasslands/deserts typically only occur where rainfall is rather scarse, hence place more forests. Though, they may have mostly been cut down by whatever civilization there may be or destroyed by various evils. The northeastern forest is somewhat hard to justify as your color scheme makes it appear the most lush on the continent. It would likely be thin and patchy, though magic can certainly be at play. The western mountains surely are the border of two plates pushing into each other. Make sure to place some volcanoes and earthquakes could be quite common. Maybe get a picture of the Andes mountains to show the players what they may look like. The eastern mountains may be a triangular plate smashing into the main continent's plate. Its point is the northeastern forest, the bulk of which lies in the ocean. Volcanoes and earthquakes here as well. Maybe get a picture of the Alps to show the players what they may look like. The small northern mountains may look something like the Appalachians, old and weathered, unlikely to have volcanoes or much seismic activity. Be sure to place some islands scattered around the continent - perhaps trailing off the northern and southern tips of the western mountains and off the two spurs of the eastern mountains as they reach the ocean. Most of the waters for the southern half of the continent dumps into the ocean from the one river that drains the lake. It would be prone to flooding and have a healthy delta.
Araes 05-27-07, 03:40 PM	In my comment I was suggesting a west to east mirroring, not a north to south. My reasoning for this was that all of the areas on the map would then work with almost no tweaking. The forest in the bottom right would now be on the windward side of all the mountains, and would be in a high rainfall area, which would make perfect sense. The lake would also be in a massive rainfall zone, and would have naturally formed. The forest in the upper right would very logically be a rainforest, because it is in a tiny area with huge walls of mountains behind it forcing all the northern rain to drop right there. The rivers on the upper right would also be more likely if they were on the windward side of the continent, as now the mountain range they are spawning from would be a west-east chain primarily, which wouldn't stop nearly so much rain on the windward side near the ocean. Here's a general picture of how I think it should work. http://araesmojo.googlepages.com/AutraliaLikeContinent.jpg
Johnny_Angel 05-27-07, 08:44 PM	Thanks for the picture Araes. Instead of flipping everything around, could I just remove some of the mountains from the west and add more to the east? (which would also save me from having to redraw a lot) I edited the picture, and I posted a second version to better illustrate what I mean: http://www.flickr.com/photos/8516524@N03/516982543/ http://www.flickr.com/photos/8516524@N03/516982543/ I was thinking that the northern part of the continent would probably be pretty dry, but I'm not sure. Also, I'm not sure if this matters, but I plan to have an island similar in size to Japan somewhere around this continent. If you can picture what Japan looks like and then rotate it so that it would be horizontal in relation to how a map is positioned. I was thinking about putting it south of this continent; roughly the same distance that Cuba is from the United States. I'm not sure if that would have any sort of noticable impact on the main continent or not.
Araes 05-27-07, 09:07 PM	Overall I think the second map you have on flickr works pretty well. I'm not sure about that river coming from the upper left, but its not a big deal. I don't think that having an island the size of japan to the south of the continent would have a major effect, but this would depend on what the general oceans are like all around the continent. Generally, how much effect does Cuba really have on N. America vs the larger effects of the Atlantic stream and the Gulf of Mexico?
Johnny_Angel 05-28-07, 02:10 PM	Do you think it would be more believable without the river on the left?
Araes 05-28-07, 08:51 PM	I personally don't think its that big of a deal. Its a little unlikely, but not implausible. I think that for the most part the continent is fine as is.