September 10-16, 2003
Midwest Weekly Highlights - September 10-16, 2003
Additional Drought Amelioration in the Western Midwest
More rain arrived in the Midwest this past week, September 10-16, but as was stated in an Iowa crop statistics report, it was "too little, too late". The heavy rains of 2 to 4 inches occurred in two bands, one stretching from northwestern Iowa to northeastern Minnesota, and the other arcing from south-central Missouri, through northeast Missouri and eastern Iowa, to eastern Wisconsin (Figure 1). The benefit to these areas was mainly in terms of soil moisture recharge for soon-to-be-planted wheat crops and for pasture health prior to winter. Only the latest planted corn or soybeans had any benefit from the rains at this stage, and the rains themselves delayed fieldwork in places. The eastern Midwest received well below normal amounts of rain for the week (Figure 2), helping this area dry out from the Labor Day flooding rains. The northern half of the Midwest was 4-8°F above normal in temperature for the week, while the far south-central and southwestern Midwest was slightly below normal (Figure 3). Topsoil moisture ratings of short or very short (s/vs) declined 26% in Iowa, to "only" 71% s/vs, and similarly declined 23% in Minnesota (to 69% s/vs), 27% in Nebraska (to 60% s/vs), and 15% in Wisconsin (to 78% s/vs). Clearly, it is still quite dry in the drought portions of the Midwest, but conditions have improved from last week in the areas receiving rain. However, some areas of the northern Midwest that missed the heavy rains this week are still deteriorating, including parts of Lower Michigan, northwestern Wisconsin, and northern Minnesota (Figure 4).
The rain in the western Midwest was derived from a very slow moving cold front sweeping directly west to east across the region during most of the period. Under very weak steering currents, the front entered the region on the 9th and did not exit the region until the 15th. Some upper level disturbances amplified the precipitation at times, so rain totals were especially large in a band from northwestern Iowa to northeastern Minnesota (Figure 5, NWS), and from Missouri, through eastern Iowa (Figure 6, NWS), to eastern Wisconsin (Figure 7, NWS). There were almost no severe weather events associated with the system, except for a noteworthy case of significant microburst damage at Creston, IA, on the 11th. In addition, because of the dry conditions preceding the rain, there was no stream or river flooding. Finally, the system did run out of moisture before reaching the eastern Midwest. While Michigan received some rain, it was not sufficient to counteract a long term decline in stream flow levels (Figure 8, USGS) or prevent some soils from being described as "powdery" in the weekly USDA reports. The path of the remnants of Hurricane Isabel may take it close enough to bring some beneficial rains to Michigan, although the same system could cause problems in already wet Ohio and Kentucky.
Agriculture at the Season's End
The percentage of corn reaching the mature stage in the Midwest was further behind the 5-year average this week than last week. Only Minnesota and Missouri are ahead of the 5-year average this week, while Indiana (-27%), Michigan (-26%), Nebraska (-22%), and Ohio (-21%) were all more than 20% behind the 5-year average for the mature stage. The percentage of soybeans dropping leaves was also falling further behind. Only Minnesota, Iowa, and Wisconsin are ahead of the 5-year average this week, while Indiana (-24%), Michigan (-24%), Nebraska (-16%), and Ohio (-29%) were all more than 15% behind the 5-year average leaf dropping stage. Much of this developmental delay comes from planting delays and cold temperatures earlier in the season, but the wet and cloudy weather last week contributed to a further delay in maturation. Iowa (33%), Minnesota (24%), Missouri (22%), and Wisconsin (22%) are ending the growing season with very small percentages of their corn rated good or excellent, while Iowa (25%), Minnesota (24%), Missouri (20%), and Wisconsin (21%) have very low percentages of their soybeans in the good to excellent quality range. Crop damage was already sealed in these states. Since the corn is drying and beans have turned yellow at this point, they have become less vulnerable to an early frost.
Due to the weather problems of August, the September 1 USDA yield estimates for corn declined 1.4 bu/acre for the US, and soybean yield estimates declined 3.0 bu/acre. The declines in projected corn and soybean yields were large in Iowa and Minnesota, where some of the worst dryness occurred during August. In Iowa, USDA corn yield projections declined 4 bu/acre from August 1, and soybean yield projections declined 7 bu/acre, with the projected economic losses from these changes alone in Iowa estimated by the USDA to be $750 M. In Minnesota, USDA corn yield projections declined 5 bu/acre from August 1, and soybean yield projections declined 6 bu/acre, with the projected economic losses from these and other agricultural problems in Minnesota estimated by the USDA to be $1.1 B. The Summer Drought of 2003 has had a tremendous economic impact on the Midwest, and still persists in large areas of this region and in the Great Plains agricultural areas. Corn production for the US as a whole will be up about 10% from last year's total and at near record levels, although soybeans will be at the lowest production level since 1996.