Sec.: __ Name: _

Experiment: Forecasting Movement of WeatherSystems (E. Science 9-16-3bb)

Purpose: To learn how to forecast movement ofweather systems.

Materials: Weather Cycler Yesterdays mapinternet - (http://www.comet.ucar.edu/dstreme)

Methods & Results: (Circle correct choice in parentheses

. to properly complete the sentence).

\ 1. Examine the Weather Cycler with the slidepushed all the way in so the L is displayed in the

'large winder. It shows that when looking down onthe low - pressure system, surface winds blow(clockwise and outward, counterclockwise andinward ) about the center.

2. preCipitation generally occurs in a broad band ahead of the ( warm, cold) front andin a narrow band along the (warm. cold) front.3. To the south and southeast of the center of the low, surface winds are likely toproduce (warm. cold) air flow.4. To the west and northwest of the center of a low, surface winds are likely to produce(warm. cold) air flow.5. Illustrate the passage of a warm front by observing the atmospheric changes in thelower windows below B as the Weather cycler slide is pulled out. With the passage ofa warm front, the air temperature usually rises and the dew point would be expected to(fall. rise ). With the approaching warm front, atmospheric pressure would (fall. rise ),

and following the front, (fall. slight rise or remain steady).6. A shift in wind direction usually accompanies the passage of a front. The WeatherCycler map shows that with passage of the warm front, surface winds shift directionfrom the to the _7. Ahead of the surface warm front, warm and humid air rides up and over a wedge ofcooler air. As the ascending warm air expands and cools, its relative humidity( increases. decrease ). and clouds may form. Most cloudiness associated with awarm front develops over a broad area, often extending hundreds of kilometer, Lahead. behind ) the front. From these clouds, light to moderate precipitation typicallyfalls for 12 to 24 hours or longer.8. As a cold air mass advances and a warm air mass retreats, the colder, denser airforces the warmer, lighter air to ascend either along or just ahead of the cold front.Uplift of warm air triggers cloud development and perhaps showery precipitation. Insome instances, uplift is so vigorous that thunderstorms develop. Typically, as shownby the Weather Cycler, the band of clouds and precipitation associated with a coldfront is ( narrower, wider) than that associated with a warm front.9. With passage of the cold front, surface winds shift direction from the tothe . After passage of a cold front, the air temperature usually falls andthe dew point would be expected to ( fall. rise ).

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Sec.: __ Name: _10. Place" B" before the cold front. With the approach of a cold front, air pressurewould (fall. rise) and following the front passage, it usually ( falls. rises ), rapidly.11. Place" Bit before the cold front. According to the station models the air movementis moving ( counterclockwise & inward. clockwise and outward ). This is ( consistent.not consistent) with the hand twist model done four days ago in lab 9-16-2b.12. Place the weather cycler pull out tab so that the H is in the middle of the window. Ifyou were located to the northeast of the H the winds would be coming from the( northwest. southwest ), which will cause the temperature in the area to ( rise. fall ).13. Because the cool air is moving in and this air mass is starting to warm up, therelative humidity will ( rise. fall ). Because of this the weather stations to the northeastof the high have ( 100. 0 ) percent cloud coverage.14. With the weather cycler still positioned so the H is in the middle of the window, thewinds to the west of the H is coming from the ( northwest. south east), which willcause the temperature in the area to ( rise. fall ).15. Because the warm air is moving in and this air mass is starting to cool down therelative humidity will ( rise. fall ). Because of this the weather stations to the west of theH have (25 to 50. 0 ) percent cloud cover~ge.16. According.to the station models the air movement is moving ( counterclockwiseand inward. clockwise and outward). This is ( consistent. not consistent) with thehand twist model done four days ago in lab 9-16-2b.17. Step outside and examine which way the wind is blowing. Then examine thesurface weather map and record where the nearest high or low pressure system is andrecord its location in reference to ourselves.

Wind is blowing from the .A pressure system is located to the of us.

18. Explain why the winds are blowing in the direction they are based on the nearestlow or high pressure system: _

19. Examine the surface weather map from yesterday, and then todays weather map.Predict what will happen to the local fronts, pressure systems, and what the weatherwill be in the next 24 hours.

front movements: _pressure movements: _weather prediction for tomorrow: _

20. Find the station models on teday's weather map for Chicago, Illinois, and Houston,Texas. Find the temperature, dew point, cloud coverage, wind direction, wind speed,pressure, change of pressure, and precipitation at each location.

Chicago: __ of, __ of, __ % of cloud coverage, .__ wind direction,__ speed of wind, __ mB, __ mB change, precipitation type.

Houston: __ of, __ of, __ % of cloud coverage, __ wind direction,__ speed of wind, __ mB, __ mB change, precipitation type.21. Now examine a current isobar map of the United States. Record the local timeand date of this map. time date _22. Examine the isobar pattern near Chicago and Houston. Near Chicago the isobarsare ( close. far) from each other compared to Houston where the isobars are relatively(close, far) from each other. Because of these findings we would predict that Chicagohas ( more. less) wind. This is ( consistent. not consistent) with results in question 20.