Dry Conditions to Persist in Western Corn Belt for Early Fall - UNL CropWatch, Sept. 18, 2012

Dry Conditions to Persist in Western Corn Belt for Early Fall - UNL CropWatch, Sept. 18, 2012

September 18, 2012

Map of 30-day departure of normal precip

Figure 1.  Percent of normal precipitation from August 19 to September 17, 2012.  Such above normal rains in the eastern Corn Belt signal the start of drought recovery.  (Source: High Plains Regional Climate Center)

Map showing departur from normal temperatures

Figure 2.  Departure from normal temperatures (F) from August 19 to September 17, 2012.  Nebraska temperatures during the period were from 0 to 5° (F) above normal.  (Source: High Plains Regional Climate Center)

There has certainly been a shift toward a more favorable moisture pattern during the past 30 days across the southeastern U.S., as well as the southern Ohio and Mississippi river valleys (Figure 1). The northwestern Corn Belt has remained dry and needs to be monitored for further deterioration during this fall and early winter. It is not uncommon for the Dakota’s, Montana, and the northern Rockies to see below normal moisture during El Nino years.

Average temperatures during the past 30 days are reflecting a change in the mean atmospheric jet stream pattern. A persistent and deep upper air trough has become established across the eastern U.S. and temperatures are responding accordingly.

Temperature departures of 1-2°F below normal are expected across the southeastern U.S. and near normal temperatures are predicted across the eastern Corn Belt (Figure 2). Abnormally hot conditions have now shifted into the northwestern Corn Belt, which includes the northwestern third of Nebraska.

The widespread precipitation that moved through the state Sept. 12-13 was certainly welcome, but insufficient to alleviate our well-established drought conditions. It is going to take several months of this type of precipitation pattern before we can expect a significant drought reduction for Nebraska.

Current Forecast

Good harvest conditions should continue into the middle of next week before another cold front begins to sag southward from Canada. If the timing works and it mixes with some expected moisture in the Rockies, Nebraska could see some rain. After that, the next moderate chance for precipitation isn’t until October 2-4.

The overall trend for the western Corn Belt is still drier than normal. While in the short-term this will benefit harvest operations, it won’t benefit wheat planting or help reduce our current drought.

Al Dutcher
Extension State Climatologist