how can changing air pressure be used to predict changing weather?
473246
Generally, storms are low-pressure areas and nice clear weather systems are high-pressure areas.  So if pressure is falling, precipitation might be coming, and if it's rising, better weather might be coming.
597267
Lower pressure will result in more "convection," or vertical movement of moisture.  So in general, the lower the pressure the better chance of precipitation.
1068629
I think you are talking about the 'Butterfly Effect' in weather forecasting.   With all the wonderful computers they have to help to forecast the weater, one of the staff was sitting in his garden when a butterfly flew past him.  He suddenly realised that the air movement caused by the wings can cause air movement which can increase over time, enough to cause a major storm in another part of the world.....................
683254
http://www.bom.gov.au/lam/Students_Teachers/pressure.shtml\nhttp://en.wikipedia.org/wiki/Weather_front
840116
I use a weather forecasting website called Metcheck.\n\nThe weather prediction for my area for December 3rd is currently shown as \n\nSun 3 Dec at 12 noon - max temp 9 °c, wind chill temp 1 °c, pressure 987 mb,  5.6 mm of rain, cloud cover 99 %  wind at 17 mph  \n\nOf course this is only a "best guess" at this stage, but they do provide frequent updates and are often extremely accurate in their short to mid range forecasts.
23682
It is an analog forecast using past weather patterns to guide the forecast.\n\nI quote:\n "Synoptic Forecast (Analogue Forecast) \n    (1).  The prior weather event associated with a given synoptic\n  weather type (pattern) in the past serves as a guide for the forecast\n   of the future weather event in case the similar synoptic type occurs.\n    (2).  Synoptic weather types\n  A.  Classification of weather types based on  the positions of\n      High and Low , upper-air flow, and prevailing storm track.\n  B.  Weather elements are predicted from the weather types.\n  C.  Example:  Hawaiian Synoptic weather types."\n\nFrom: http://www.csun.edu/~hcgeg004/forecast.html
487478
Contact the National Weather Service\n\nwww.weather.gov
908777
Temperature is temperature no matter what elevation or altitude you are at - no need to know it.\n\nIf you want to correct station pressure readings to sea level for a weather station, then it may be helpful. The most practical and a reasonably accurate method though is to simply set your barometer several times (making small adjustments) to the sea level pressure using data from a good surface chart during daytime on a nice day with a weak pressure gradient (when it'll be very similar over tens of miles). Here is a good site for observations the past hour:\n\nhttp://www-frd.fsl.noaa.gov/mab/metar\n\nThey say data are experimental and not always accurate blah blah blah - but I never saw an error in METAR listings for any of the stations nor their locations - though you have to be able to read METAR reports. E-mail me if you wish regarding this.\n\nWhatever the case, Topozone is good if you want your elevation for any particular reason:\n\nhttp://www.topozone.com
331961
It indicates a drop in pressure which usually means windy weather on the way and probably rain too.
803179
Changes in air pressure and possibly humidity.  Your body turns into a barometer.
471029
They know where air masses originate & how cold those air masses are when they start at their source region.\n\nAs the air mass moves across the continent, it changes in temp to that closer in temp to the air mass already in place.\n\nFor instance, if an air mass orginates over nothern Canada, it will be dry & cold. As it moves south, it will start taking on characteristics of the areas that it moves over. It will get warmer. By the time it reaches say, Mexico, it will have warmed up tremendously.\n\nThey can predict how much kinetic energy will be gained or lost by that.\n\nI don't think there is an exact formula for this kind of science. Most of predicting the weather is actually "predicting"!\n\n;)
535634
Changes in barometric pressure do cause changes in both human and animal behavior. Ask any veteran teacher...they can tell a lot about how the day will go just by the weather that morning...
66785
Latitude, altitude, prevailing winds.
602607
Weather satellites are used to collect basic data, such as temperature and moisture levels, which allows experts to predict weather to a reasonable extent. Past attempts to control weather have been largely unsuccessful and have centered mainly in trying to create rain.
799074
How scientific do you want it?\n\nBasically, air circulates the earth.\n\nThis air has different temperatures in different places.\n\nThe different temperatures cause different pressures of air masses.\n\nBecause of this air flows around air masses due to the pressure gradient between different masses.\n\nThis air flow drags air of even higher temperature differences into contact.\n\nDifferent air temperatures meet causing one to rise over the other, as this rising air goes up it cools and causes clouds (These areas where air masses join are the fronts on a weather map).\n\nThese clouds then produce rain.\n\nThat rain changes temperatures, more air masses are drawn into contact, and the cycle repeats.
45731
when there is a low pressure system that brings all the air towards it
80805
Not sure about forecast, but Kestrel makes some amazing anemometers (wind meters), some with barometers and altimeters built in.