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'j I I VI. RAINFALL DISTRIBUTION The precipitation leading up to the growing season was one of the bright things to come along in many year for most in Kansas. Superb snowfall during the winter brought excellent moisture to the region and set up the 1990 growing season with above normal 5011 moisture. Figure 6, on the following page. shaws the Long-Term Draught Severity Index for soil moisture conditions during most af the Kay - August period and is produced by the NOAA/USDA Joint Weather Facility in Washington. D,C. This index comes out every two weeks and is published weekly in the periodical, "Weeklv Weather and Gran Bulletirr', The index is not prone to short-term moisture changesj therefore. it normally takes periods of weeks or months to change, not days. The index is developed from official statistics and has its own problems as far as total accuracy and representativeness is concerned. However, the areas categorized are more likely to be closer to exhibiting the tendency of the category shown than not. I It can be seen on Figure e that as we approached May 1st, the soil moisture was considered "moist" for much of southwest Kansas. As the season progressed, we continued seeing the favorably moist area in southwest Kansas except for late July when we appeared to be more "normal", or not short of deeper moisture, Again, by mid- August, the latest information available for which this report was based, showed another "bullseye" appearing over southwest Kansas again. We would like to caution the reader that this is a long- term soil moisture measurement, not a rainfall statistic. There were extensive areas within the area shown as being moist that appeared to have well-below summer rainfall this season. I As Figure 6 shows. on August 18th the Weekly Weather and Crop Bulletin indicated southwest Kansas was sandwiched between two areas of severely dry areas to our southeast in Oklahoma and to the northwest in Nebraska and Colorado. The fact that this favorably moist area in the drought severity index appears at all is both interesting and encouraging to us as cloud seeders. As noted earlier. July was a record month for cloud seeding operations and 55 of the seasonal 256 flights ended up being solely to seed clouds to augment rainfall. There were 65 other flights that were combinations of hail suppression and rainfall augmentation. In all, 120 of the 256 flights (47%) had some rainfall augmentation performed. We did have two heat waves that made a significant impact on the region duri'ng the growing season. Very dry conditions were produced that undoubtedly affected the index during the season, One of the heat waves began in late June and continued into July; the other came at the end of August and is continuing into early September as this report is being written. 28