Instability and Severe Weather. Assignment 7. Due February 6

On May 24 2000, a young girl was killed by lightning in Murray and a tornado went through the Holladay area on the 25th. This exercise is designed to investigate the use of morning soundings to identify the conditions that are favorable for severe weather, even though the details of where and when severe weather may take place can not be answered by a sounding alone.

1. Bring up the sounding for SLC at 12z, 25 May using Nsharp.

a. Determine the initial wet bulb temperature and the LCL.

b. Would a parcel lifted from the surface to the LCL be likely to continue to ascend?

c. What would the parcel's temperature be if it was lifted to 500 mb?

d. What would be its lifted index?

e. What is the parcel's level of free convection?

f.If the parcel were to be lifted to its level of free convection, what would be its equilibrium level?

g. What are the Nsharp estimates of CIN and CAPE? What do these numbers indicate to you regarding the likelihood of convection?

2. Continuing with the 12z sounding.

a. As an estimate of the situation as surface heating develops during the day, what is a surface parcel's convective condensation level? convective condensation temperature?

b. If the afternoon temperature would reach the convective condensation temperature, what would be the parcel's temperature if it was lifted to 500 mb? lifted index? level of free convection? equilibrium level?

3. Now overlay the 00z, 26 May sounding. Describe the changes in temperature, moisture, and wind as a function of height from the morning until the afternoon.

4. Repeat 2a-g.

5. Would you expect that the tornado has already taken place in the Salt Lake area by 00z, is imminent, or will happen 6-12 hours later. Explain your reasoning.