NAME DATE VOCABULARY: Synoptic weather map- WEATHER PATTERNS Isotherm- Barometric Pressure- Isobar- Convergence- Divergence- Cyclone- Anticyclone- Air mass- Source region- Front- OBJECTIVE: Construct a series of field maps to learn to identify patterns that can be used to predict the weather. 145
146 MAP 1: TEMPERATURE PATTERNS
PROCEDURE 1: 1 1. On Map 1 use a pencil to draw isotherms at 10 o intervals hint start with 30 o. 2. After making sure isotherms are correct, color code the temperatures in the following way. (20s- purple, 3os-dark blue, 40s- light blue, 50s-green, 60syellow, 70s-orange, 80s- red) DISCUSSION QUESTIONS: 1. What is the general appearance of the isotherms on this map? 2. As you go from North to South how does the temperature change? 3. Near which cities is the temperature gradient the greatest? 4. Calculate the temperature gradient between Buffalo and Richmond. SHOW ALL WORK AND LABEL PROPERLY. 5. Calculate the temperature gradient between Seattle and San Francisco. SHOW ALL WORK AND LABEL PROPERLY. 147
148 MAP 2: BAROMETRIC PRESSURE
PROCEDURE 2: 2 1. On Map 2 use a pencil to lightly draw isobars between points of equal pressure. Use a 4mb interval- hint start with 1000.0 mb (000) 2. Trace over the High pressure system with blue and label with an H in the center of the system. Trace of the Low pressure system with red and label with an L in the center of the system. DISCUSSION QUESTIONS: 1. What is the general appearance of the isobars on this map? 2. Which city is the Low Pressure center near? 3. Which city is the High Pressure center near? 4. What is the highest air pressure on the map? 5. What is the highest value for an isobar on Map2? 6. As you travel from Salt Lake City to Seattle, what change in atmospheric pressure takes place? 7. Calculate the pressure gradient between New Orleans and Chattanooga. SHOW ALL WORK AND LABEL PROPERLY. 149
MAP 3: SURFACE WIND PATTERNS 150
PROCEDURE 3: 3 1. On Map 3 extend the shaft of the wind arrow through the station model and draw an arrow head to show the direction the wind is blowing. 2. Trace over the arrows representing the winds in the high pressure system in blue and the arrows representing the low pressure system in red. 3. Draw larger arrows to show the general air movement in each pressure center. DISCUSSION QUESTIONS: 1. Where is the greatest change in wind direction in the eastern part of the country? 2. In a Low Pressure System how does the air move? 3. Are surface winds in a low pressure area convergent or divergent? 4. In a High Pressure System how does the air move? 5. Are surface winds around a high pressure area convergent or divergent? 151
MAP 4: PRECIPITATION PATTERNS 152
PROCEDURE 4: 4 1. Draw a line connecting the areas where there is precipitation. Precipitation is represented with an R in the center of the station model for the purpose of this activity. 2. Lightly shade in the area where precipitation is occurring with blue. 3. On Map 3 label the location of the continental polar (cp) and maritime tropical (mt) air masses with the appropriate symbols. DISCUSSION QUESTIONS: 1. In comparison to cp (Continental Polar) an mt (maritime tropical) air masses where is precipitation occurring? 2. Describe step by step how clouds form. 3. Why do areas of High Pressure have fewer clouds than Low Pressure Systems? 153
MAP 5: SYNOPTIC WEATHER MAP 154
PROCECURE 5: 5 1. Refer to the previous 4 maps and draw isobars, wind patterns, area of precipitation on Map 5. 2. Using all information obtained in previous maps, draw in the cold and warm fronts with proper symbols on Map 5. DISCUSSION QUESTIONS: 1. In comparison to the cold front, where does precipitation occur? 2. In comparison to the warm front, where does precipitation occur? 3. What are the two characteristics that are used to describe an air mass? 4. Compare the characteristics of an air mass to its source region. 5. Compare the following conditions on either side of the cold front: a. Temperature: b. Air pressure: c. Wind direction: 155
CONCLUSION QUESTIONS: 1. Describe the weather conditions associated with a high pressure area in regards to: a. temperature: b. wind patterns: c. cloud development: d. precipitation: 2. Describe the weather conditions associated with a low pressure area in regards to: a. temperature: b. wind patterns: c. cloud development: d. precipitation: 156