Lab 19.2 Synoptic Weather Maps Name: Partner: Purpose The purpose of this lab is to have you read and interpret the information displayed on synoptic weather maps. You will also learn the techniques used by meteorologists to analyze weather maps and the weather conditions associated with frontal systems. Materials Colored pencils Weather Maps: isobar, front, radar, data surface chart, current 500 mb-data upper air chart Procedure A: Complete the following steps. 1. On a separate piece of paper, decide and write out the current weather conditions for the ten station models in Figure 19.2.1. 2. On the back of the same piece of paper you used to decode the ten station models, encode the following six current weather conditions in station model format. Station Model A The sky is clear. The wind is from the south at five knots. The barometric pressure is 1024.8 mb and it has risen 2.4 mb in the past three hours. The air temperature is 74 F and the dew point is 66 F. Station Model B The wind is from the northwest at 15 knots. Cloud cover is 25 percent. The present weather is drizzle. There has been 0.2 inches of rain in the past six hours. The barometric pressure is 974.6 mb and it has fallen 9.2 mb in the last three hours. The air temperature is 62 F and the dew point is 61 F. Station Model C The sky is totally overcast. The present weather is fog. The air temperature is 76 F and the dew point is 74 F. There has been 0.6 inches of rain in the past six hours. Barometric pressure is 999.9 mb and has fallen 3.6 mb in the past three hours. The wind is from the north at 20 knots. Station Model D The sky is 75 percent covered. The wind is from the southeast at 25 knots. The barometric pressure is 999.0 mb and has dropped 7.2 mb in the past three hours. It is raining and the air temperature is 79 F, and the dew point is 74 F. There has been 0.5 inches of accumulation of rain in the past six hours. Station Model E The sky is clear. The wind is calm. The barometric pressure is 983.0 mb and rising. The air temperature is 70 F and the dew point temperature is 62 F. The visibility is five miles with no precipitation.
Station Model F The sky is half covered. Thunderstorms are threatening. There has been 0.1 inches of accumulation of rain. There is a westerly wind at 10 knots. The barometric pressure is 1005.8 mb and has dropped 8.2 mb in the past three hours. The air temperature is 72 F and the dew point is 71 F. Procedure B: Complete the following steps. 1. Use the surface weather map data provided to draw the weather conditions on the blank map in Figure 19.2.2A with the appropriate colors. Your weather map should include the locations of high- and low-pressure centers, fronts, and precipitation. 2. Use the 500-mb upper air chart to locate the jet stream. Upper air maps can be analyzed by drawing an arrow through each wind vane of the individual weather station pointing in the direction the wind is moving. The jet stream can be located by identifying the band of highest wind velocity. Once you have identified the jet stream s location, draw it in using a green colored pencil on your weather map. 3. Using data on your weather map and the location of the jet stream, predict what the weather conditions will be in 24 hours. On the blank map in Figure 19.2.2B, draw the locations of the high and low pressure, fronts, and precipitation to make a forecast map for the next day.
Figure 19.2.1A and B Weather Forecast
Procedure C Using your textbook, fill in the appropriate weather conditions associated with each type of front on Table 19.2.1 Air Temp. in Front Table 19.2.1 Fronts Cold Front Warm Front Air Temp. in Back Cross-Section Cloud Type Pressure in Front Pressure Behind Frontal Symbol Precipitation
Conclusions 1. Describe the change in wind direction associated with the low-pressure system moving through your area. 2. What general weather conditions are associated with high-pressure systems? 3. What would you expect the weather conditions to be like if the barometric pressure trend over the past three hours has shown a steady decline? 4. What is the jet stream, and why is it an important aspect of weather forecasting? 5. Explain what information you need to make accurate weather forecasts.