39. Nor’westers and Monsoon Prediction. 
By EK. Diesy. 
INTRODUCTION, 
These few remarks are set out to suggest a correlation be- 
tween the leading characteristics of the nor’ westers occurrin 
during the hot weather transition periods and the following 
monsoon, together with a discussion of the probable formation 
of these interesting minor storms. The paper is intended to 
be suggestive only since the author has unfortunately collected 
insufficient data to establish the theory or frame anything 
more than tentative rules of forecasting. The latter would 
probably need the experience of some fifteen or twenty years 
before anything of value could be deduced. 
istory of monsoon prediction in India has been a 
chronicle of the continual widening of the area of enquiry and 
observation. Deductions obtained from the preceding winter’s 
is a balancing of conclusions drawn from Abyssinia, South 
America, Australia and the remoter Indian Ocean. A forecast 
based upon so many, often conflicting, variables cannot hope 
to be completely satisfactory, though the Meteorological De- 
partment may congratulate itself upon the near approach to 
success with which the annual problem is attacked. 
One of the main difficulties of the situation is the lack of 
well-marked air disturbances of any great duration during the 
Six months before the rains. In Bengal the date of the re- 
versal of the lower air-currents from north to south and the 
commencement of the hot weather is about the only well- 
marked phenomenon from which deductions can be drawn. 
There are no large cyclonic storms and the investigation of the 
upper air-currents has up to now, for lack of sufficient money 
and trained observers, been insufficiently extensive to prove of 
In order to obtain well-marked phenomena metecrologi- 
cal research has had to travel extensively round the southern 
hemisphere. 
There is, however, one series of events in India itself 
which has been overlooked by investigators in search of ope 
