What is Weather: Definition and 180 Discussions

Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature, precipitation, and other atmospheric conditions, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth.
Weather is driven by air pressure, temperature, and moisture differences between one place and another. These differences can occur due to the Sun's angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the Hadley cell, the Ferrel cell, the polar cell, and the jet stream. Weather systems in the middle latitudes, such as extratropical cyclones, are caused by instabilities of the jet streamflow. Because Earth's axis is tilted relative to its orbital plane (called the ecliptic), sunlight is incident at different angles at different times of the year. On Earth's surface, temperatures usually range ±40 °C (−40 °F to 104 °F) annually. Over thousands of years, changes in Earth's orbit can affect the amount and distribution of solar energy received by Earth, thus influencing long-term climate and global climate change.
Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes, as most atmospheric heating is due to contact with the Earth's surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Earth's weather system is a chaotic system; as a result, small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture and industry have modified weather patterns
Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. However, the weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind.

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  1. fernandavbc

    Hello from Brazil!!

    Hello, everyone! I already follow a weather forum here in Brazil, but I'm also very interested in astrophysics and want to stay up-to-date with solar activity as much as possible.
  2. Astronuc

    FIRO - Forecast-informed Reservoir Operations

    Ignoring the part about fossil fuels, or the prediction of demand, I heard an interesting discussion about using more reliable forecasting in conjunction with dam/reservoir operation...
  3. nsaspook

    Is Hurricane Hilary Approaching Miami?

    Tropical Update from the NHC in Miami, FL. (August 18, 2023)
  4. A

    B Questions about climate and physics

    1)The atmosphere is an extremely complex system, so much so that weather forecasts beyond a few days are not possible. Why are seasonal or 10-20 year climatological forecasts reliable? I heard from a climatologist in a video on YB (I know it is not a valid source) that weather forecasts are an...
  5. Ivan Seeking

    News Chinese "weather" balloon shoot-down over US

    Balloon shot down. It sounds like we do plan to retrieve it. They shot it down before it was over international waters. [Thread split off from the Weird News thread]
  6. K

    The Probability of Rain: A Meteorologist's Perspective.

    I searched, "is infinity possible?" Because I was coming up with some thoughts which seemed logical (I hope) so I was compelled to find others discussing the topic to see if I even came close to several different answers.
  7. fella1973

    I Is the hot weather causing bursting airbeams when camping?

    Im a keen camper and for my family tent I have been a long time convert to airbeam tents as opposed to poled tents. There is a lot of anecdotal evidence that the recent spate of hot weather has led to increase in burst airbeams due to the higher temperatures, but i find it hard to believe that...
  8. PhanthomJay

    Probability of Rain in weather forecasts

    I am trying to settle a debate over two definitions of the 'probability of rain' in a weather forecast area. Definition 1 states that for example there is a 50% averaged probability of rain at some point in the forecast area over a given duration of time, that is, there is a 50-50 chance that I...
  9. GhostLoveScore

    Construction Temperature inside a weather station enclosure

    Hello I have a digital thermometer that I put into a wooden enclosure. It has horizontal holes drilled into its sides all around to let air in. On the bottom there is an opening around 1/3 of the width, like in attached photo. And I was thinking about certain thing. When I put a bare...
  10. G

    I Explain how soil is not frozen after 3 weeks of below freezing weather

    It has been below freezing for 3 weeks, 12°F at night and in mid 20s during the day. Yard and garden are frozen 2" deep hard as cement everywhere except 3 row in the garden covered with 1/2" of pine needles. Soil under pine needle is not frozen I can push my finger into the soil 3" deep. How...
  11. Borek

    Tonga eruption shockwave and weather station(s) in Poland

    Warsaw times, subtract 1 hour for GMT. It was pointed to me yesterday that we should see these by the same guy that sends helium filled balloons around the world (his latest is in the air for about half a year now), I posted about him some time ago. He posted an image from his weather station...
  12. kyphysics

    Are Old Weather Conditions Officially Tracked?

    Any official (scientific, verified) tracking of old weather conditions that one can look up? Say, I wanted to know what the weather was like in Kentucky in the city of Lexington on October 24th, 1983. Is there some kind of official recorded archive to look such information up?
  13. Fisic

    I How weather conditions affect a golf shot

    Please correct me if I'm well off the fairway with the following theory. We all know that atmospheric conditions (temperature, pressure, dewpoint, etc.) can affect many different bodies in motion, from aeroplanes to cars to golf balls. But in the case of a golf ball, exactly how big is the...
  14. StevieTNZ

    Getting rid of a new weather icon on my Windows 10 taskbar

    I installed a security update for Windows 10 and now I'm stuck with this awful icon on my taskbar: How do I remove it? Many thanks Stevie
  15. S

    Models for weather that include data from amateur stations?

    I have the impression (I've not actually researched the matter) that some online weather services publish data from weather stations set up by amateurs. Do any organizations incorporate such data in their weather prediction models? I'd think that using such data would involve a sophisticated...
  16. mbrmbrg

    Goal of The Weather Report e-Mail Hack?

    Hey, a month or two ago, my old Gmail account was hacked. The whole situation was/is pretty identically to what this thread describes very well: https://support.google.com/accounts/thread/42850129?hl=en I've written off the old account and am no longer attempting to recover it. But the emails...
  17. iVenky

    B Why does my head feel heavy when I go out on a cold weather day?

    Is it because of increase in pressure on my blood vessels due to cold weather outside?
  18. S

    What causes the weather? (not the seasons)

    Hello. One winter can be mild and snow free, while the next winter is a frozen wasteland. One summer can be blistering hot, while the next is rather cool. More specifically, if you take that example down to the day, then why can the weather be drastically different on July 31st 2020 compared to...
  19. S

    Definition of temperature in weather reporting

    In my town, newspaper stories say we've had several days of record high temperatures. The stories report temperatures in the range of 107 F. However, on the same days, online weather reports show temperatures as high as 116 F. I think online weather reports use reports from amateur weather...
  20. M

    Optical Laser to refract/reflect water vapor and smoke.... angles?

    Building visibiity sensor... What is best angle to detect water vapor reflection from laser, and refraction? I plan to have two open cylindrical containers painted flat black and put inside each other so the overlap is about 0.5-1" (adj to limit ambient light vs airflow). Laser is cheap red...
  21. P

    Weather data from every planet

    I was curious about how much we could advance planetary science with the amount we are spending (and planning to spend) on the SLS. Specifically, I want us to increase the number of climates we study from basically Earth to every planet in the solar system. It looks like polar orbiting...
  22. C

    I Transporting an Ice Cream Tub in hot weather

    It was hot and I bought a tub of ice cream to take home. I put the AC on and blew into the footwell where the ice cream was. Was that sensible? Is it better to let a static layer of cold air surround the tub of ice cream (say at -5C), or to blow cold (~+10C) air over it when the ambient in...
  23. S

    How bad will the sale of the spectrum down to 24.25 GHz be for weather radar?

    I was reading this, and got concerned: https://slate.com/technology/2019/05/spectrum-auction-bandwidth-weather-forecasting-fcc-noaa.html
  24. haushofer

    I Conceptual question about the Coriolis force and the weather

    Dear all, there is something bugging me for a while now, and it's about a favourite topic of confusion: the Coriolis-force! A fictitious force is a force which disappears if you transform to an inertial frame. At the algebraic level I have a good understanding of this, I think (Newton's 2nd...
  25. V

    How can California's timber industry help reduce the risk of wildfires?

    I been keeping an eye out on the recent fires we are experiencing around the California, Oregon, Washington and in the Idaho areas. It seems like as years go by fire season is getting worse. What really spooks me is that the drought areas are spreading to larger regions and impacting wild...
  26. fresh_42

    B Have you seen the Space Showers in Chicago?

    I just found this online service http://nusoft.fnal.gov/nova/public/ which shows a different kind of weather: Space Showers in Chicago.
  27. S

    Cloud cropping/plureite sensors

    I saw a video on facebook recently of some sort of devices making circles in the clouds, revealing the blue sky above. I thought at first this was fake but apparently not. Someone provided the explanation using the above terms...cloud cropping and plureite sensors, but I can no longer find the...
  28. J

    Statistical mechanics and the weather

    Hi all. Where can I find some good introductory sources teaching the use of statistical mechanics to study things like tornado formation or climate in general? I took P. Chem., a while ago now but I'm reviewing the material independently. We used one of Moore's texts, 80's - ish, and in it he...
  29. Z

    Tornadoes and angular momentum

    I explained this thinking to a meteorologist once and she couldn't give me an answer. Any physicists want to give it a shot? I find the typical explanation of tornadoes perplexing (that's a polite way of saying I don't believe it). The explanations I've seen claim that tornadoes start out...
  30. ryan liberty

    I Source of the weather on Neptune

    With the fastest sustained wind speeds in the solar system of 700mph. The main explanation I have heard is Neptune's primordial heat from it's formation combined with the lower atmospheric drag due to lower temperature. Neptune's southern hemisphere is currently in summer and has gotten warmer...
  31. R

    Divide observational data into normal periods for study

    When analyzing hydrological and climatological timeseries/observations it is common practice to compare statistics made on normal periods. As WMO calls them "WMO Climatological Normals". These periods consist normally of 30 years of data. If you want to compare two normal periods with each...
  32. A

    Archimedes' Principle and a weather balloon

    Homework Statement 2. Homework Equations Buoyant force= mg(mass of fluid displaced = Vpg (volume of fluid displaced) Buoyant force=weight of object (if floating) The Attempt at a Solution If the total mass is 99kg, then the total force acting downwards is 990N. It also said that the balloon...
  33. scottdave

    Science which goes into computing hurricane predictions

    With Hurricane Harvey hitting the Texas Gulf Coast, I came across this article, while trying to learn about these different computer models. I found the article in this PDF file an interesting read. I'm sure that there have been some advances in real-time prediction methods, since this article...
  34. Stavros Kiri

    Stargazing Solar Activity and Space Weather Update thread

    I am picking this up as a continuation and extension of the idea laid out e.g. in @davenn 's thread "The Sun today - 9 July 2017 - nice spot group" https://www.physicsforums.com/threads/the-sun-today-9-july-2017-nice-spot-group.919696/ See also (for continuity purposes)...
  35. Blank_Stare

    Electric conductivity loss due to weather on electric fence wire?

    Greetings Denizens!, I'm building a small "zapper" for the purpose of keeping critters away from a deer feeder. Other than volts and amps ratings, I believe it is, for all intents and purposes an electric fence, just in a unique configuration (shape, not electrical specs - those are within the...
  36. C

    How long does it take for the temperature on Earth to....

    How long does it take for the temperature on Earth to cool down after the sun has set? I want to know if the total solar eclipse will change the temperature.
  37. Toreno

    Stargazing Lightning ball - me to analyze this rare video

    Hi, Some time ago I was looking for lightning ball videos on youtube. I observed some strange phenomenon recorded on one of the videos. Before a lightning ball is created, some "dark" ball is coming from above and then it immediately changes to the lightning ball which is moving at different...
  38. R

    I How to determine energy savings from weather and usage data

    I bought a Nest thermostat a few months ago and I wanted to figure out how much energy it has statistically saved me. I have my usage data going back four years (I track the utilities to split with roommates) and I can find the historical weather data for my area for each day of the month. One...
  39. BillTre

    Attempts to Unify Climate and Weather Prediction Models

    Open access news article from Science magazine news. I found this interesting, but it is really beyond my ability to provide a short explanation.
  40. S

    I How would weather differ on a planet with a longer day?

    Hypothetical question that came up in World Building stack exchange. The question asked for what the longest reasonable day length would be. I thought that a 100 hour day: * Afternoons in what are now hot deserts would be uninhabitable. * Frost traps in more polar climates would be...
  41. wasup23

    I How does relative humidity drop below 100%

    How is it that once the dew point is reached, moisture continues to condense. What is causing the imbalance of partial water vapor pressure? Does the rise in atmospheric temperature simply pass up the evaporation rate too quickly?
  42. J

    Writing: Input Wanted An Alternate to the Siberian Traps

    Back home, the catalyst for the worst biotic catastrophe in the world, the Siberian Traps, don't have much left. 252 million years of erosion have reduced the igneous province to a pale shadow of its former self. From 60 to 43 million years ago (not 252), a series of flood basalt eruptions...
  43. 1oldman2

    Exploring Earth's Interior with Seismic Tomography and Weather Bombs

    This could open a new frontier on seismic study of the Earth's interior. http://www.bbc.com/news/science-environment-37177575 From, http://science.sciencemag.org/content/353/6302/919 Seismic tomography is like an x-ray of Earth's interior, except that it uses earthquakes for the illumination...
  44. avito009

    Why Does More Vapour Form When Taking a Bath in Colder Weather?

    When the temperature in a city is lower and one has a bath in the bathroom then why does more vapour get created? More vapour than it would be created when the temperature is higher?
  45. Square1

    Need help understanding pressure vs weather systems

    This is a subject that confuses me for a long time. Everywhere I go to get an understanding, I seem to run into the same explanations over and over which don't really do that much explaining. I find that only the basic elements of weather are explained, and overly basic examples that utilize...
  46. Shadow-Shocker

    LabView Weather Station Exercise problem

    I am doing a Weather Data Log exercise, and I am looking for the program to run continuously. However, every time I run it, the program would always direct me to store the data in a file for every run I do. Please look at the following pic. Btw, I am running this on a Mac, using parallel's...
  47. mfig

    Why does barometric pressure differ from measured pressure?

    I live in Denver CO, and I have come across a mystery having to do with barometric pressure. If you go look at any weather site, like: http://www.wunderground.com/cgi-bin/findweather/getForecast?query=denver+co You will see the local pressure (at the time of this writing) is listed as 30.33...
  48. P

    Magnetic waves/fields that precede cold weather fronts....

    Are magnetic waves that travel ahead of low pressure wx fronts, a certain frequency? Are they a sign wave? Is it possible to cancel a magnetic wx front wave on a local basis by generating an 180 degree out of phase signal at the same frequency like you would a voltage wave? Is the magnetic wave...
  49. craigi

    Information Preservation and Weather Forecasting for Black Holes

    http://arxiv.org/pdf/1401.5761v1.pdf Abstract: It has been suggested that the resolution of the information paradox for evaporating black holes is that the holes are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling observer. Such firewalls would break the...