148 



SOUTHERN APPALACHIAN REGION. 



Temperature. temperature of the region <a.s a whole can not well 



be stated, wince it is in general propoi-tional to the altitude 

 and is always higher on southern than on northern slopes. 

 Few meteorological observations of any character whatso- 

 evei' have been made except in the valleys and lower 

 levels; indeed, with the exception of a few months' obser- 

 vations on the summit of Mount Mitchell, no meteorologi- 

 cal observations are available for the 4,00()-foot level and 

 l)ut two series of observations for the level between 3,000 

 and 4,000 feet. 



The monthly means and exti'emes of temperature, to 

 which reference will aga-in be made, are given for a num- 

 ber of stations in the tables which accompan}- this paper, 

 weather types! The wind System of the southern Appalachians in spring, 

 fall, and winter is largely conditioned l\y the movement in 

 latitude of cyclonic and anticyclonic storms. In the sum- 

 mer season these disturbances move across the country so 

 far to the northward that their influence upon the weather 

 of the southern Appalachians is almost inappreciable. The 

 winds of summer will depend very largel}' upon the con- 

 tour of the countr}^ being upward from the valleys along 

 the mountain side during the day and downward at night, 

 with a general westerly drift over the mountain summits. 

 In the more boisterous circulation of spring, late fall, and 

 winter the winds are almost wholly controlled by the 

 atmospheric disturbances passing eastward over the lake 

 region or northeastward from the Gulf of Mexico. 



The movement of cyclonic storms eastward across the 

 lake region produces a type of weather in the southern 

 Appalachians which, for convenience, ma}" be called the 

 southwest t3'pe. The chief characteristics of this tvpe are 

 southwesterly winds with I'ising temperature and increas- 

 ing cloudiness. The velocity of the wind generally in- 

 creases for a day or so, and finallj^ shifts to the west and 

 noi'thwest, with lower temperature, but not much rain. 

 The southwest is the most common type experienced, and 

 is often associated with long periods of fair, diy weather. 



Next in point of frequency to the southwest type is what 

 may be called the vjest gulf ty^iDC, from the fact that the 

 weather with which it is associated is produced by storms 

 which approach from the west Gulf States. In this type 

 fresh to brisk southeast to east winds are experienced with 

 generally heavy rain throughout the entire region. As 

 soon as the storm passes the winds shift to a westerly 



