Study Guide: Weather Patterns Lessn 1: Watching the Cluds G By Cntent Objectives: Cluds frm when large areas f warm, mist air rise int the air t the pint where water vapr cndenses int water drplets. There are three main types f cluds: Cumulus, Stratus, and Cirrus. Certain types f cluds can be used t predict the weather. Cmputers and machines that help us predict the weather are pretty new. It wasn t that lng ag when peple had t depend n what they bserved in nature t tell them what the weather might be. Tday we have all srts f technlgy that prvides infrmatin abut weather. Satellites, weather ballns, cmputers, radar, as well tls like barmeters, anemmeters, thermmeters, and wind vanes, all prvide infrmatin abut what is happening in the atmsphere. Weather frecasters use this infrmatin t make predictins abut the weather. In the early 1800s, a scientist named Luke Hward created a way t classify cluds. He realized that cluds lked differently, but there were three main types: cumulus, stratus, and cirrus. Cumulus cluds are puffy and lk like cttn candy r cttn balls. They frm when large areas f warm mist area rise up int the atmsphere. Stratus cluds lk like gray blankets that cver the sky. They are frmed when large areas f warm, mist air rises slwly int the sky. Cirrus cluds are the highest cluds. They lk like cmmas r wisps f hair. Cirrus cluds are frmed when the air rises high enugh that the drplets freeze int ice crystals. Inside the three families f cluds are different types f cluds named fr where they can be fund in the trpsphere and whether r nt they are a rain clud. If a clud has nimb- r -nimbus in its name, it is a rain r snw clud. Examples are nimbstratus and cumulnimbus cluds. If a clud has cirr- in its name, it frms high in the sky. Examples include cirrstratus and cirrcumulus. Cluds with alt- in their name frm in the middle f the trpsphere, like altstratus and altcumulus. Cluds can be used t predict the weather. Cirrus cluds and alt- cluds can mean that rainy r snwy weather is n the way. Cumulus cluds appear in sunny summer skies, and altstratus cluds can mean that the weather is ging t dry up. Weather satellite: devices in space that are used t cllect weather infrmatin Cumulus cluds: puffy cluds that lk like cttn balls Stratus cluds: flat, gray blanket cluds that seem t cver the sky Cirrus cluds: lk like cmmas r wisps f hair. Created when air rises high enugh fr ice crystals t frm. Nimb-/-nimbus: this prefix r suffix means the clud is a rain clud (Ex: nimbstratus) Cirr- : this prefix means the clud frms high in the sky (Ex: cirrstratus) Alt- : this prefix means a clud frms at a middle height (Ex: altcumulus)
Lessns 2: Predicting the Weather Cntent Objectives A weather frecaster is smene wh makes predictins abut the weather using data cllected frm weather instruments. Warm frnts usually bring light rain r snw, and cld frnts usually bring thunderstrms. Weather frecasters are men and wmen wh make predictins abut the Weather frecaster: a scientist wh predicts the weather weather. They may be n the TV news, wrk fr an airprt, the newspaper., r smething else entirely. Wherever they wrk they must cllect data, r Air mass: a bdy f air that infrmatin, abut the weather t make accurate predictins. Weather satellites, has the same general weather ballns, radar, cmputers, barmeters, anemmeters, and thermmeters temperature and pressure Frnt: a place where tw are sme tls that prvide this infrmatin. Frecasters take all the data and different air masses meet lk at it clsely t make their predictins. They can never be cmpletely crrect Warm frnt: when a mass f because the weather is always changing. As yu knw, air surrunds the Earth, but the air in ur atmsphere is warm air mves int a mass f cld air. Often brings rain r actually divided int large areas called air masses. An air mass is a bdy f air snw. that has the same general temperature and pressure thrughut it. Sme f these Cld frnt: when a mass f air masses are warm and sme are cld. cld air mves int a mass f Cld frnts are frmed when a cld air mass mves int a warm air mass. warm air. Often brings thunderstrms. The cld air is heavier than the warm air, s the warm air is pushed up ver the cld air. This ften causes thunderstrms r cumulnimbus cluds t frm.! Warm frnts are frmed when a warm air mass mves int a cld air mass. The warm air is lighter than the cld air, s it rises up ver the cld air. This ften causes light rain r snw. High-pressure areas (air masses that have higher pressure than the air arund them) usually bring clear, dry weather because the high pressure pushes Wind mves frm high pressure t lw pressure. Strng winds are caused by big differences in air pressure and hw clse the air masses are t each ther. the strms fund in lw-pressure areas away. Lw-pressure areas (air masses that Lw pressure = strms have lwer pressure than surrunding air) usually bring wind, cluds, r rain. High pressure = dry weather Cld Frnt Warm Frnt
Lessn 3: Light and Sund Shw Cntent Objectives A thunderstrm is a strm that prduces heavy rain, strng winds, lightning and thunder. Thunderstrms are cumulnimbus cluds frmed when warm mist air rises mre quickly and higher int the atmsphere than usual. When lts f warm, mist (humid) air rises quickly and higher int the atmsphere than usual, a cumulnimbus clud can frm. These cluds are thunderstrms, als called thunderheads, and they create heavy rain, strng winds, lightning and thunder. Cumulnimbus cluds usually frm alng cld frnts, and where the air is very ht and humid. When there are strng winds several miles abve Earth s surface, they can pull lts f warm, humid air up frm the grund very fast. This causes the thunderhead t grw taller. Sme cumulnimbus cluds can actually be several miles tall, and very wide as well. Inside the clud there are very strng winds swirling in all directins. As raindrps begin t frm, they are carried up and dwn inside the clud. Smetimes the raindrps freeze, but are then carried back up int the clud, where they gain anther layer f water which freezes. The ice pellets cntinue mving up and dwn inside the clud, getting bigger and bigger until they re t heavy and fall t Earth. This is hw hail is frmed. The mvement f ice and water drplets up and dwn inside the clud als creates static electricity. As it mves thrugh the atmsphere, the negative charges in the clud cllect at the bttm f the clud. This attracts psitive charges n the grund, and repels the negatives. When a negative charge frm the clud cnnects t a psitive charge frm the grund, a giant static discharge is created. This static discharge is lightning. Lightning is extremely ht, fast, and pwerful. It can reach temperatures htter than the surface f the sun (54,000 O F). When lightning mves thrugh the atmsphere, it heats the air s that it expands very quickly. This is hw thunder is created. Thunder is the sund f lightning, and it happens at the same time as lightning. Hwever, we hear thunder after we see lightning because light travels faster than sund. Thunderstrms end because the rain cls the air belw the clud. Since thunderstrms need warm, mist air t cntinue, withut it, the clud breaks apart and the strm ends. Thunderstrm: a strm that prduces heavy rain, strng winds, lightning and thunder Cld frnt: when a cld air mass mves int a warm air mass, ften bringing thunderstrms. Thunderhead/Cumulnimbus: ther names fr a thunderstrm Lightning: a flash f light and heat (static discharge) created by static electricity in a thunder clud. Thunder: the sund f lightning. Created as the air is heated by lightning. Hail: pieces f ice that fall t Earth frm a cumulnimbus clud Flash fld: sudden, vilent flds Thunderstrms can cause prblems n the grund. They ften prduce a lt f rain that can cause flash flds. Heavy hail can damage prperty. Lightning can cause fires and pwer utages.
Lessn 4: The Fiercest Strms n Earth Cntent Objectives A hurricane is a large, vilent strm that creates strng winds and waves, and frms ver warm cean water. A trnad is a funnel-shaped strm f spinning wind. Hurricanes and trnades are the mst pwerful strms n Earth. They bth create strng winds that can cause a lt f damage. Althugh they are similar in sme ways, they are different as well. Hurricanes are very large strms with vilent, pwerful winds. Althugh we call the hurricanes in ur part f the wrld, they are called typhns in the west Pacific and cyclnes Hurricanes frm near the equatr, ver warm cean water. They start as strng thunderstrms that may jin tgether t frm ne large strm clud. T becme a hurricane, the winds need t be at least 70 mph, but sme can have speeds that are twice that. Thunderstrms can smetimes prduce trnades. A trnad is a funnel-shaped strm f spinning wind. Trnades usually happen n land thse that frm ver water are called water sputs. They frm when winds rll acrss the grund and then are pushed up int the atmsphere, frming a fast spinning clumn f air. The air pressure in the center f the funnel is very lw. Althugh trnades are smaller than hurricanes, they can be extremely dangerus. Wind speeds during a trnad can reach as high as 300mph: twice as fast as a Categry 5 hurricane. These winds can lift almst anything ff the grund and int the air: dirt, trees, rfs, and cars. Trees, huses, and buildings can be destryed. Hurricane: a large vilent strm that frms ver warm cean water. Hurricanes bring strng winds and waves. Typhn: the name fr a hurricane that frms in the west Pacific Ocean Cyclne: the name fr a hurricane that frms in the Indian Ocean Trnad: a funnel-shaped strm with spinning wind. Twister/Funnel-clud: ther names fr a trnad