AT 540 – Synoptic Weather Analysis – Lab 3 Thickness and Thickness Advection Thickness (11) 1. (7) Answer the following questions about 1000-500 mb thickness and its relationship to precipitation type. Be sure to show your work. a. (2) On a 1000-500 mb thickness map, most of the U.S considers the 5400 m line as the rain/snow dividing line. Explain which side of the line snow would likely fall and why. b. (1) Calculate the layer-averaged virtual temperature for a thickness of 5400 m. c. (2) In Fort Collins, we consider the 5520 m thickness line as the rain/snow dividing line. Calculate the layer-averaged virtual temperature of the atmosphere for this thickness. Assume sea-level pressure at Fort Collins is 1000 mb and ρ=1.1 kg m-3. d. (2) Explain why Fort Collins might expect snow with larger 1000-500 mb thicknesses than other parts of the country. In your discussion, also compare your answers to parts b and c.2 2. (4) Use the map below to answer the following questions. a. (2) Assuming that precipitation is falling, would you expect rain or snow in Fort Collins? Explain. b. (2) On the map, draw fronts where they may possibly exist. Explain your reasoning.3 Thickness Advection (9) 3. (1) Explain the relationship between thickness advection and temperature advection. 4. (8) Use the maps below to answer the following questions.4 a. (2) On the first map (12Z analysis), shade the areas of warm air advection in red and the areas of cold air advection in blue. b. (2) Based on this, would you expect the thickness to increase or decrease across North Dakota? Why? c. (2) Compare your answer to b with the second map (12 hr forecast, valid 00Z). Explain how you could use this information in forecasting. d. (2) Label all troughs and ridges on the second map with the appropriate