The accompanying diagrams show surface temperatures with isotherms labeled in degrees Fahrenheit for

The accompanying diagrams show surface temperatures with
isotherms labeled in degrees Fahrenheit for noon and 6 p.m. on January 29,
2008. On this day, a powerful front moved through Missouri and Illinois

a. What type of front passed through the Midwest?

b. Describe how the temperature changed in St.

Louis, Missouri, over the 6-hour period.

c. Describe the likely shift in wind direction in St.

Louis during this time span.