Editing Meteorology (section)

===Weather forecasting===
{{Main|Weather forecasting}}
[[File:Day5pressureforecast.png|thumb|upright=1.35|Forecast of surface pressures five days into the future for the north Pacific, North America, and north Atlantic Ocean]]

Weather forecasting is the application of science and technology to predict the state of the [[Earth's atmosphere|atmosphere]] at a future time and given location. Humans have attempted to predict the weather informally for millennia and formally since at least the 19th century.<ref>{{cite web|website=Mistic House |url=http://www.mistichouse.com/astrology-lessons.htm |title=Astrology Lessons |access-date=12 January 2008 |archive-url=https://web.archive.org/web/20080608133837/http://www.mistichouse.com/astrology-lessons.htm |archive-date=8 June 2008 |url-status=dead}}</ref><ref>{{cite web|first=Eric D. |last=Craft |url=http://eh.net/encyclopedia/article/craft.weather.forcasting.history|title=An Economic History of Weather Forecasting |date=7 October 2001 |website=EH.net |publisher=[[Economic History Association]] |archive-url=https://web.archive.org/web/20070503193324/http://eh.net/encyclopedia/article/craft.weather.forcasting.history |archive-date=3 May 2007 |url-status=dead |access-date=15 April 2007}}</ref> Weather forecasts are made by collecting quantitative [[data]] about the current state of the atmosphere and using scientific understanding of atmospheric processes to project how the atmosphere will evolve.<ref>{{cite web|url=http://earthobservatory.nasa.gov/Library/WxForecasting/wx2.html |title=Weather Forecasting Through the Ages |work=NASA |archive-url=https://web.archive.org/web/20050910210732/http://earthobservatory.nasa.gov/Library/WxForecasting/wx2.html |archive-date=10 September 2005 |url-status=dead |access-date=25 May 2008}}</ref>

Once an all-human endeavor based mainly upon changes in [[Atmospheric pressure|barometric pressure]], current weather conditions, and sky condition,<ref>{{cite web|website=The Weather Doctor |url=http://www.islandnet.com/~see/weather/eyes/barometer3.htm |title=Applying The Barometer To Weather Watching |archive-url=https://web.archive.org/web/20080509105153/http://www.islandnet.com/~see/weather/eyes/barometer3.htm |archive-date=9 May 2008 |url-status=dead |access-date=25 May 2008}}</ref><ref>{{cite web|first=Mark |last=Moore |date=2003 |url=http://www.nwac.us/education_resources/Field_forecasting.pdf |title=Field Forecasting—a short summary |work=[[Northwest Weather and Avalanche Center|NWAC]] |archive-url=https://web.archive.org/web/20090325034756/http://www.nwac.us/education_resources/Field_forecasting.pdf |archive-date=25 March 2009 |url-status=dead |access-date=25 May 2008}}</ref> [[numerical weather prediction|forecast models]] are now used to determine future conditions. Human input is still required to pick the best possible forecast model to base the forecast upon, which involves pattern recognition skills, [[teleconnection]]s, knowledge of model performance, and knowledge of model biases. The [[chaos theory|chaotic]] nature of the atmosphere, the massive computational power required to solve the equations that describe the atmosphere, error involved in measuring the initial conditions, and an incomplete understanding of atmospheric processes mean that forecasts become less accurate as the difference in current time and the time for which the forecast is being made (the ''range'' of the forecast) increases. The use of ensembles and model consensus help narrow the error and pick the most likely outcome.<ref name="Klaus">{{cite web|first1=Klaus |last1=Weickmann |first2=Jeff |last2=Whitaker |first3=Andres |last3=Roubicek |first4=Catherine |last4=Smith |url=http://www.cdc.noaa.gov/spotlight/12012001/ |title=The Use of Ensemble Forecasts to Produce Improved Medium Range (3–15 days) Weather Forecasts |publisher=[[Earth System Research Laboratories]] |website=cdc.noaa.gov |archive-url=https://web.archive.org/web/20071215055130/http://www.cdc.noaa.gov/spotlight/12012001/ |archive-date=15 December 2007 |url-status=dead |access-date=16 February 2007}}</ref><ref name="TBK">{{cite web |first=Todd |last=Kimberlain |url=http://www.wpc.ncep.noaa.gov/research/TropicalTalk.ppt |title=TC Genesis, Track, and Intensity Forecating [sic] |website=wpc.ncep.noaa.gov |date=June 2007 |access-date=21 July 2007 |archive-date=27 February 2021 |archive-url=https://web.archive.org/web/20210227154914/http://www.wpc.ncep.noaa.gov/research/TropicalTalk.ppt |url-status=live }}</ref><ref>Richard J. Pasch, Mike Fiorino, and [[Chris Landsea]]. [http://www.emc.ncep.noaa.gov/research/NCEP-EMCModelReview2006/TPC-NCEP2006.ppt TPC/NHC’S REVIEW OF THE NCEP PRODUCTION SUITE FOR 2006.]{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }} Retrieved on 5 May 2008.</ref>

There are a variety of end uses to weather forecasts. Weather warnings are important forecasts because they are used to protect life and property.<ref>{{cite web |url=http://www.weather.gov/mission.shtml |title=National Weather Service Mission Statement |website=weather.gov |publisher=[[National Oceanic and Atmospheric Administration|NOAA]] |archive-url=https://web.archive.org/web/20080612134118/http://www.weather.gov/mission.shtml |archive-date=12 June 2008 |url-status=dead |access-date=25 May 2008 }}</ref> Forecasts based on temperature and [[Precipitation (meteorology)|precipitation]] are important to agriculture,<ref>{{cite web|first=Blair |last=Fannin |url=http://southwestfarmpress.com/news/061406-Texas-weather/ |title=Dry weather conditions continue for Texas |date=14 June 2006 |work=Southwest Farm Press |archive-url=https://web.archive.org/web/20090703095038/http://southwestfarmpress.com/news/061406-Texas-weather/ |archive-date=3 July 2009 |url-status=dead |access-date=26 May 2008}}</ref><ref>{{cite web|first=Terry |last=Mader |url=http://beef.unl.edu/stories/200004030.shtml |title=Drought Corn Silage |date=3 April 2000 |publisher=[[University of Nebraska–Lincoln]] |website=beef.unl.edu |archive-url=https://web.archive.org/web/20111005203246/http://beef.unl.edu/stories/200004030.shtml |archive-date=5 October 2011 |url-status=dead |access-date=26 May 2008}}</ref><ref>{{cite web|first=Kathryn C. |last=Taylor |url=http://pubs.caes.uga.edu/caespubs/pubcd/C877.htm |title=Peach Orchard Establishment and Young Tree Care |date=March 2005 |publisher=[[University of Georgia]] |website=pubs.caes.uga.edu |archive-url=https://web.archive.org/web/20081224112403/http://pubs.caes.uga.edu/caespubs/pubcd/C877.htm |archive-date=24 December 2008 |url-status=dead |access-date=26 May 2008}}</ref><ref>{{cite web|url=https://www.nytimes.com/1991/01/14/us/after-freeze-counting-losses-to-orange-crop.html |title=After Freeze, Counting Losses to Orange Crop |date=14 January 1991 |work=The New York Times |agency=[[Associated Press]] |access-date=26 May 2008 |archive-url=https://web.archive.org/web/20180615190918/https://www.nytimes.com/1991/01/14/us/after-freeze-counting-losses-to-orange-crop.html |archive-date=15 June 2018 |url-status=live}}</ref> and therefore to commodity traders within stock markets. Temperature forecasts are used by utility companies to estimate demand over coming days.<ref>{{cite web|work=The New York Times |agency=[[Reuters]] |url=https://www.nytimes.com/1993/02/26/business/futures-options-cold-weather-brings-surge-in-prices-of-heating-fuels.html |title=FUTURES/OPTIONS; Cold Weather Brings Surge In Prices of Heating Fuels |date=26 February 1993 |access-date=25 May 2008 |archive-url=https://web.archive.org/web/20180615135320/https://www.nytimes.com/1993/02/26/business/futures-options-cold-weather-brings-surge-in-prices-of-heating-fuels.html |archive-date=15 June 2018 |url-status=live}}</ref><ref>{{cite web|url=http://news.bbc.co.uk/1/hi/uk/5212724.stm |title=Heatwave causes electricity surge |work=BBC News |date=25 July 2006 |access-date=25 May 2008 |archive-url=https://web.archive.org/web/20090520060913/http://news.bbc.co.uk/1/hi/uk/5212724.stm |archive-date=20 May 2009 |url-status=live}}</ref><ref>{{cite web|url=http://www.tcdsb.org/environment/energydrill/EDSP_KeyMessages_FINAL.pdf |title=The seven key messages of the Energy Drill program |website=tcdsb.org/environment/energydrill |publisher=[[Toronto Catholic District School Board]] |archive-url=https://web.archive.org/web/20120217042744/http://www.tcdsb.org/environment/energydrill/EDSP_KeyMessages_FINAL.pdf |archive-date=17 February 2012 |url-status=dead |access-date=25 May 2008}}</ref> On an everyday basis, people use weather forecasts to determine what to wear. Since outdoor activities are severely curtailed by heavy rain, snow, and [[wind chill]], forecasts can be used to plan activities around these events, and to plan ahead and survive them.