April 13, 2007

Below-normal Soil Temperatures Continue

April has brought record low temperatures, periodic precipitation events with accumulating snowfall, high winds, and soil temperatures in the 30s. This current weather pattern is what we would expect in March, not at the onset of corn planting.

The past two weeks have reinforced concerns raised during much of March about the prospects for significant planting delays due to an abundance of moisture. The two most current events (April 10-11 and 13-14) have only increased problems. Abundant moisture, scattered snow, and cold temperatures have resulted in muddy surface conditions with soil temperatures running 10-15 degrees below normal.

Even the Climate Prediction Center has revised their April outlook from above normal temperatures to normal temperatures. So far, temperatures have averaged 8-10 degrees below normal for the month and will need to average 5-6 degrees above normal for the remainder of the month just to get April back to normal. We would normally expect highs currently to be in the low 60s, warming into the low 70s by month's end.

A brief warming trend does appear to be in the offing for much of next week. High pressure will build over the central U.S. and temperatures will rebound into the 60s and 70s; however, models predict another potent storm will hit Nebraska as early as April 21, bringing a chance for heavy rain and an outside chance for accumulating snowfall. After the system departs to the east, dry conditions and temperatures moving into the 70s will return to the region.

With the abundance of moisture, soil temperatures are going to respond to air temperature increases much slower than we have been accustomed to during the past few years when much drier spring planting conditions prevailed. It very well may take up to a week of high temperatures in the 60s before 4-inch soil temperatures get back to 50°F. This would present a very narrow window of favorable soil planting temperatures before next weekend's storm.

The current moisture pattern and cool conditions resemble a similar pattern in 1999. Wet conditions prevailed from April through early June and endless planting delays were common. If an extended dry weather pattern doesn=t develop within the next few weeks, I wouldn=t be shocked to see corn planting extended into the second half of May.

Al Dutcher
Extension State Climatologist