1890.] Relations hetiveen the Hills and Plains of Northern India. 25 



weather conditions and relations in the hills and plains of Upper India 

 daring the cold weather. These are as follows : — 



1st. — The prevalence of fine clear weather with light winds or calms 

 in the hills and plains. These conditions accompany prolonged anti- 

 cjclonic pressure conditions of moderate intensity in Upper India, and 

 may be described as " ordinary anticyclonic conditions." They obtain 

 frequently during the cold weather. 



2nd. — The prevalence of disturbed or stormy weather in the hills 

 and plain districts. This type of weather is due to the formation, 

 passage, or existence of cold weather depressions. Skies are heavily 

 clouded, rain falls more or less generally in the plains of Upper India, 

 and heavy general snow is received in the higher mountain regions 

 down to a level determined chiefly by the intensity of the storm. Winds 

 are weak in the plains, but their directions usually indicate feebly mark- 

 ed cyclonic circulation about an ill-defined centre. The winds are on the 

 other hand often strong or violent and the weather very stormy in the hill 

 districts for periods varying in length from a few hours to several days. 

 These periods may be described as those of *' cold weather cyclonic 

 storms." 



Zrd. — The prevalence of unusually bright clear cool weather such as 

 always obtains over the whole of Northern India, after the breaking 

 up of a large and well marked cold weather storm. In this case, a strong 

 and steady cool westerly current flows from Upper India and the ad- 

 jacent hills over the whole of Northern India as far east as the Bengal 

 coast. The air is remarkably dry and bracing. The change of condi- 

 tions is most marked in Bengal, where the weather during the previous 

 unsettled period is usually damp, cloudy, and warm, with light southerly 

 winds. 



These are the three chief types of weather in Northern India du- 

 ring the cold weather period extending from November to February or 

 March. They merge into each other, more especially (3) and (I). 

 Again it frequently happens that small depressions pass over Upper 

 India which give a brief period of cloudy weather without rain in the 

 plains, and light local rain or snow showers in the hills. The pre- 

 cipitation in this case is almost entirely confined to the higher elevations. 

 This type of weather gives rise to somewhat different temperature 

 relations than (2). They will, however, be included in (2) as it is 

 hardly possible to differentiate between all the numerous varieties of 

 cold weather storms. 



The temperature conditions and relations in ordinary anticyclonic 

 weather in Upper India will be sufficiently shewn by the following data 

 given in three small tables for the two pairs of stations, Marree and 

 4 



