NO. 9 FORECAST OF U. S. PRECIPITATION — ABBOT 69 



through the summer of 1958. On the other hand from the summer 

 of 1952 through the autumn of 1956 the country was generally dry. 



This interpretation of generality over the country is justified by 

 the fact that the high points of figure 12 depend on observations of 

 identity of signs for more than 20 out of 32 cities, in 15 cases. Some 

 peaks are supported by 28 cities out of 32. 



When both curves are near the heavy horizontal line the precipita- 

 tion of the country as a whole was nearly normal. That is, through 

 1950 and the first four months of 1951, and for portions of the years 

 1953, 1954, and 1957 precipitation generally averaged nearly normal. 

 The curves of figure 12 show plainly that the entire country is subject 

 to nearly simultaneous trends of precipitation, depending, as they do, 

 on nearly universal agreement of observations of departures in 32 

 cities over an interval of 9 years. 



With this result established, turn to the two upper curves on fig- 

 ure 12. These are plotted similarly to those below, but are from 

 table 13 which gives the 4-month mean departures from normal pre- 

 cipitation forecasted 1959- 1967. 



Reading these upper curves: After the dry winter of 1959 there 

 should follow a short well-watered interval, and an interval of nearly 

 normal precipitation before a rather well-watered period in i960. 

 Then, following normal precipitation in 1961, should come pretty dry 

 conditions in the winter and early summer of 1962. A long period of 

 normal rainfall follows from the autumn of 1962 through the summer 

 and autumn of 1964. A very wet winter of 1965 follows, and fairly 

 normal precipitation thereafter, except for the dry summer of 1966. 



The last preceding paragraph concerns the country as a whole. 

 For details of forecasts for individual stations, the predictions may 

 be found in tables 12 and 13, and in the 27 maps of the United States. 



MAPS 



Twenty-seven maps of the United States follow, with circles show- 

 ing location of 32 cities. Numbers above the circles refer to the cities 

 given in table 13, which are numbered correspondingly. Numbers 

 below the circles give percentage departures from normal precipitation 

 as forecasted as means for 4-month intervals in table 13, 1959-1967, 

 A, B, and C, for each year. Three maps form one chart. The nine 

 charts are dated from 1959 to 1967. 



