Before mentioning many of the mysteries of weather, first we should decide what weather is. Customarily with literature, "we" is the author, though I tend to avoid that nonsense. Unless you tell me what you think though, we can't change our definition Anyway, here's my definition (for Earth) :

Weather : Natural occurrences in and motion of the gaseous atmosphere above the Earth, particles not artificially suspended in it, and direct physical consequences of these.

Considering that definition, weather includes sunshine, clouds, rain, snow, hail, tornadoes, wind, hurricanes, lightning, dust devils, duststorms, sea and land breezes, dew, frost, air pollution, volcanic ash, sea spray, condensation nuclei, terrestrial radiation, ionization of upper atmospheric gases, ozone formation and destruction, neutrinos passing thru our atmosphere, etc. and any direct physical affects they may cause such as wind breaking branches off a tree or freezing rain making the ground icy. Further affects such as someone slipping on this ice (after it is formed) is not considered a direct physical consequence. Weather does not include particulate matter artificially propelled thru or suspended in our atmosphere such as frisbees, airships, weather balloons or monitoring instruments, nor natural objects transiently passing thru the atmosphere such as an acorn falling from a tree.

The above discussion is not meant to be confusing - it is simply established so any specific phenomenon can clearly be considered as being part of weather or not being so. For example, I consider air pollution a part of weather, being gases, liquids, or particles suspended in the atmosphere. Though they might've been artificially propelled into the atmosphere, they are not artificially suspended in it as a dirigible is. You may argue that the dirigible affects weather when suspended, and it does; but so do towers, buildings, etc. which are attached to the Earth (and thus considered as being part of the Earth). If the dirigible or tower are struck by lightning, the lightning and its direct damage are part of weather. I include the damage (direct physical affect) because the weather phenomenon is responsible for altering the previous state of the object. Once its state is altered, any further affect is not part of weather.

Weather variables are often considered as being weather - temperature, humidity, wind speed, etc. Similarly as wind speed describes magnitude of wind motion, temperature describes magnitude of molecular air motion. Though they help a person's perception of the weather, they are not among the occurrences which comprise weather.

Weather includes only terrestrial occurrences - within significant influence of Earth's atmosphere. Anything outside is considered as being in outer space, or extraterrestrial. Such a boundary does not truly exist. I.e., at an altitude of about 31 km, atmospheric pressure is only about 1 % (.01) as at the surface, quickly decreasing as altitude increases. At altitudes of several hundred km and above, amounts of matter largely depend on the solar wind, particles left from previous comets, and meteors. Just enough atmosphere exists at the these typical altitudes of polar orbiting satellites such that drag forces very gradually alter their orbits. Concentrated at about 80-400 km altitudes, X-ray and ultraviolet solar energy ionizes some molecular air components, causing D, E, and F ionospheric layers. Interaction of solar plasma (charged particles) with Earth's magnetic field often causes brilliant aurorae around polar magnetic field cusps. There and above, a diffuse part of the solar "atmosphere" interacts with both Earth's magnetic field and Earth's atmosphere, creating among other things radiation belts - regions of large proton and electron concentrations - often named for James Van Allen, discoverer and a researcher of these. Note the shape of such belts and their occurrence at altitudes greater than previously mentioned. At about 400 km altitude, little atmosphere exists and radioactivity is evidently just weak enough such that it is not extremely detrimental for terrestrial life. Considering these things, 400 km is perhaps a good choice for the boundary.

A brief mention of this is helpful for maintaining focus regarding and clarifying our goal. Perhaps I am biased regarding clouds, being my first topic of detailed study, but their influence regarding weather most relevant for us is great enough such that some people have suggested methods of forecasting weather primarily using cloud observations. Other than earth's orbital characteristics :

and its consequences :

they most significantly influence solar energy. Solar energy (radiation) and terrestrial energy cause the diurnal (day/night) cycle. Most everyone is aware that solar heating occurs during daytime, mainly near ground, but Earth & its surroundings constantly radiate heat to space, during day and night. When solar heating is absent, cooling occurs. A theory exists that because heat is eventually equally distributed among hot and cold objects, a universal temperature of about 3 °K will exist. Among the diurnal cycle's many consequences include maximum and minimum temperatures, daytime and nocturnal boundary layers, convection, low-level jet streams, sea/land breezes, and local cloudiness characteristics. When studying weather, a person should keep in mind weather characteristics most relevant regarding her/his main interests and how phenomena studied may influence them.

When measurements of atmospheric pressure, temperature, humidity, wind, cloudiness, and precipitation became abundant enough, synoptic weather charts were drawn, on which weather characteristics at various places at a specific time (or relatively closely) were included. Because mass-communication did not exist, such charts could only be drawn forensically, but included a synopsis of weather info previously unavailable. Some researchers previously noticed correlation of low atmospheric pressure with inclement weather (and vice-versa), but among the most relevant things synoptic charts revealed was existence of cyclones and anticyclones - large areas of minimum and maximum air pressure around which winds circulate counterclockwise and clockwise (in the Northern Hemisphere), respectively. As observing and communication techniques improved (e.g., telegraph), near-current info regarding such pressure systems, temperatures, weather became available. Even today, with sophisticated electronic and satellite measurements of weather parameters and communications, data availability remains a problem for some locations and situations. During the early 1900's a frontal theory was developed at the Bergen school of meteorology, associating cyclones with observed fronts and their characteristics. The theory is good enough such that not many adjustments and improvements regarding the basic theory are necessary.

Our universe is supposed as created with a "big bang" billions of years ago (how many, 4-20 ? is debatable, though some people are very confident of their ideas). From this, elementary atomic and subatomic particles supposedly formed, later becoming more sophisticated (greater atomic number), many molecules forming also. Frequency shifts of objects sensed in space indicate general movement away from the location where such a bang possibly occurred. In our skies, we can see some of the hundreds of billions of galaxies, many arranged in clusters, one of which is our Milky Way galaxy (the word galaxy is from the Greek word gala, meaning milk). The 2 basic galaxy types are X and spiral galaxies, the latter of which ours is. Similarity among its shape and that of hurricanes is interesting, with spiral arms (ala rain bands) around a more massive nucleus (ala eye & eyewall), though I think eyes are rather unique for hurricanes and some strong extratropical cyclones. In each, a force causes the bands to spiral toward the center - for the galaxy, it is gravity; for the hurricane, it is low pressure causing air convergence there. Our solar system is estimated as being in one of Milky Way's spiral arms, about 2/3 from the center. If you live at a rural location, you can see evidence of the Milky Way galaxy's shape - concentration of stars in a band - which is sort of like looking at a frisbee from its side.

Our solar system contains everything our sun's gravity retains as orbiting bodies. Our sun is at its center, and at least 9 planets and their moons, asteroids, comets, and meteors. Each orbit our sun or planets, though our sun and planets capture some (and portions thereof) with insufficient escape or orbital speed. Perhaps you are unaware that spacing of the inner planets is rather organized, suggesting that the asteroid belt between Mars & Jupiter either was once a planet, or one which never formed. The universal law of gravitation describes all of such motion very well. This is more so observation than theoretically-based. I do not think any person presently knows exact causes of gravity, but we know its affects, which is often sufficient for effective problem-solving. This description is not perfect, because it includes only Newtonian physical considerations, not relativistic ones. Not so significant regarding magnitudes - e.g., solar eclipses can be accurately forecast using the Law of Gravitation - but perhaps regarding a basic understanding of how all objects relate with each other, which can be an important consideration for forecasting events, as I've previously mentioned. As an astrologer once stated "To be a good astrologer, you must be a good mathematician".

Text and images are copyright of Joseph Bartlo, though may be used with proper crediting.