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Unformatted text preview: Jon Ahlquist 11/17/2006 MET1010 Intro to the Atmosphere 1 Chapter 13: Weather Forecasting Forecasting is like driving a car down the road where you are only allowed to look out the back window. - Source unknown Utility of weather forecasts Weather observations and analysis at surface and aloft Weather forecasting methods Accuracy versus Skill Probability forecasts Numerical (i.e., computer) forecasts Ensemble forecasting You can forecast Watches, warnings, and advisories Utility of Weather Forecasts Meteorologists cant change the weather, but forecasts can help people prepare for it. What to wear Travel (driving, airlines, shipping) ) US National Weather Service is in Dept of Commerce Construction Agriculture Forest fires Tourism Good forecasts are based on good observations and a good understanding of the underlying science. ASOS: Automated Surface Observing System Most surface observations come from ASOS. Roughly 1000 ASOS stations in US, operated by National Weather Service, FAA, and military. ASOS automatically and electronically measures temperature, relative humidity, pressure, wind speed and direction, rainfall, visibility, height of cloud ceiling (but not cloud type). Also determines whether precipitation is rain or snow and whether there is freezing rain. At airports, people are contracted to take hourly observations of cloud type and weather that may be missed by ASOS (high clouds & weather in area) US Radiosonde Network Roughly 92 stations launching twice daily over US. N Hemisphere coverage is good for observing mid- latitude cyclones over land but inadequate in space and time to provide good observations of thunderstorms Can reach 100,000 ft during 90 minute ascent Equipment: about $100 per launch. Few recovered. Next generation sondes with GPS will cost about $160 each, so desirable to increase recovery rate. One possibility: glidersonde (glider the size of model airplane equipped with weather instruments). Takes observations as it is lifted by weather balloon. Released from balloon at preset altitude and glides back to launch point. Upper air obs info: http://www.ua.nws.noaa.gov/ US Radiosonde Stations Other Observing Tools in US 2 geosynchronous satellites for E & W of US: www.goes.noaa.gov 164 Doppler radars covering US; see www.nws.noaa.gov/ost/88dtech.html 35 profilers, most in middle third of US, measure wind speed and direction as a function of height, reporting hourly (www.profiler.noaa.gov) Jon Ahlquist 11/17/2006 MET1010 Intro to the Atmosphere 2 Other Observing Tools in US Roughly 500 commercial aircraft carry weather sensors & report 150,000 observations per day, mostly in the upper troposphere (called ACARS, MDCRS, and AMDAR. http://aviationweather.gov/ general/pubs/front/docs/jul-03.pdf, http://acweb.fsl.noaa.gov/) Anchored buoys in Caribbean & Atlantic; also in the Pacific Ocean along & near the equator to monitor El Nino....
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This note was uploaded on 07/21/2011 for the course MET 1010 taught by Professor Staff during the Fall '08 term at FSU.
- Fall '08