Tennessee has three distinct geographical and cultural regions represented by the three stars at the center of the State flag: West, Middle and East Tennessee. The lowlands of West Tennessee are bordered by the Mississippi River on the west and a portion of the Tennessee River on the east. Aside from the city of Memphis, land in West Tennessee is primarily agricultural. Nashville, the State’s capital, is located in Middle Tennessee, an area characterized by rolling hills and fertile river valleys extending eastward to the Cumberland Plateau. East Tennessee is dominated by the Appalachian Mountains and foothills, including the Cumberland Mountains, the ridge-and-valley area with its principle urban areas of Knoxville, Chattanooga and the Tri-Cities, and the Great Smoky Mountains that straddle our border with North Carolina.
The varied topography of Tennessee leads to diverse climate conditions, 3 but overall the State has a temperate climate with hot, humid summers and mild winters. Tennessee has four major climate (Figure 1). Across the State, the average annual temperature varies from over 62°F in the extreme southwest to near 45°F atop the highest peaks of the east. Tennessee’s moist air primarily comes from the Gulf of Mexico to the south, so there is a gradual decrease of average precipitation from south to north across the State. The average annual precipitation across Tennessee ranges from approximately 40 inches in the northern portions of the Great Valley of East Tennessee to up to 80 inches in the peaks of the Smokey Mountains. Average annual snowfall varies from 4 to 6 inches in the southern and western parts of the State to more than 10 inches in the mountains of the east. However, due to relatively mild winter temperatures, snow cover in most locations rarely persists for more than a few days.
Tennessee’s climate is also prone to variability that contributes to extreme events. Tennessee’s most important flood season occurs during the winter and early spring when frequent storms bring general rains of high intensity that contribute to local or more widespread flooding. Such storms can also be accompanied by damaging winds and hail and may occur as tornadoes. Heavy summer thunderstorms also result in local flash flooding. Flood-producing rains are general rare in the fall, although occasional tropical storm systems may cause serious floods as they pass through the area. Tennessee winters can be accompanied by ice storms in some areas.