292 EXPERIMENT STATION RECOKD. 



METEOROLOGY. 



The rainfall of Nebraska, G. 1). Swezey and G. A. Loveland 

 {N^ehraska iSta. Bui. 15, pp. 1:^9-177, charts 37). — A complete record of 

 observations on rainfall in Nebraska from 1876 to 1895 is given in tables 

 and charts. In preparing tlie charts of normal rainfall ''only those 

 stations were used which had a complete record for this period, or, if 

 certain months or years were wanting from the record, the amount of 

 rainfall for these missing periods was taken by estimation from the 

 monthly or annual charts of precipitation for these months or years. 

 Since these charts were compiled from the data furnished by all the 

 stations in the vicinity of the stations in question, they furnish a valu- 

 able clew to the probable rainfall of a given locality." 



"The precipitatiou in Nebraska occurs mainly in connection with the passage of 

 areas of low liarometer across the country. The prevailing direction of our rain- 

 beariug winds is from the southeast, and, by tracing these winds back to their 

 source, it is found that in a large percentage of cases they come from the region of 

 the Gulf of Mexico. . . . 



"These southerly moisture-laden winds, flowing northward in advance of alow 

 barometer area and cooling as they go, precipitate more or less of their moisture on 

 the eastern or southeastern side of the low area; much of the rainfall in the summer 

 occurs in couuection with thunder storms which form as a rule in the southeastern 

 quadrant of the area of low barometer. After the low area has passed and the 

 winds have changed to northerly directions behind it, still further precipitation 

 often occurs from the cooling of the moist atmosphere by the admixture of the cold 

 air imported from the north with the warm, moist air originally derived from the 

 southeast. 



"Much of the winter precipitation falls as rain rather than as snow. Heavy falls 

 of snow occasionally occur, but much of the time during the winter the ground is 

 bare in the southern half of the State. 



"The total amount of precipitation for the year in Nebraska and adjacent regions 

 ranges from about 13 in. at the extreme southwestern corner of the State to about 

 34 in. at the extreme southeastern. . . . The average annual rainfall for the State 

 as a whole is 23.33 in. . . . [Of this] 16.08 in., or 69 per cent of the entire amount, 

 falls during the 5 months of the growing season, April to August inclusive. . . . 



"[Nebraska therefore has] the advantage over the States lying farther to the east 

 that a large percentage of its rainfall occurs in the growing season, when it is most 

 useful. . . . 



"At the western end of the State the largest monthly rainfall occurs in May ; farther 

 east the rainfalls of May, June, and July are not greatly different; while at the 

 extreme eastern end of the State the period of greatest rainfall is delayed until June. 



" [From the observations recorded] it appears that there is rain in Nebraska at any 

 one locality on the average 1 day in 4, and that when it rains there falls on the aver- 

 age about a quarter of an inch a day; . . . that there are but 6i days in the year in 

 which as much as aii inch falls in a day, although the total amount falling in these 

 quantities is of course considerable; . . . that but a trifling amount of the total 

 yearly precipitation falls in showers of less than one-tenth of an inch per day; . . . 

 and that the greatest uncertaiutj- as to the amount of pi'ecipitation occurs in those 

 months of the year when but little falls in any case. During the 5 months of the 

 growing season, Ax)ril to August, inclusive, the liability to a deficiency does not vary 

 greatly, although the greatest uncertainty occurs unfortunately in the mouth of July, 

 when a deficiency is liable to aft'ect the corn crop so seriously. . . . 



"If we examine the precipitation for the series of years from 1849 to 189.5, inclusive, 

 we shall find that, although the rainfall of the past few years has been less than that 



