By Jennifer Stewart, Purdue University
A very dry Indiana November and abnormally warm start to December have sparked some nervous chatter in the agriculture community on the heels of the worst drought in decades, but the Indiana State Climate Office says it isn't time for farmers to panic.
A cold November brought only 28% of normal rainfall to the state, but a northward shift of the jet stream and storm track are bringing warm, wet weather back to Indiana. With no definitive pattern in effect this year, such as El Niño or La Niña, that weather variability is likely to continue throughout the winter months, said Ken Scheeringa, Indiana associate state climatologist, based at Purdue.
"Our weather is going to continue to flip back and forth between dry and wet, but winter can be known for that. Don't get too locked into one mode," Scheeringa said. "Farmers like to look ahead to spring planting, but a lot can happen between now and April. We have four months for soils to fully recharge and our wet, early fall had already started this process.
"The combination of low winter evaporation rates and the harvest of corn and soybeans behind us means soil water demand is lower at this time of year, giving soils a chance to catch up. Even with little to no rain, soils aren't likely to lose too much moisture."
The lack of November rain caused parts of northern Indiana to slip back into moderate drought, according to the U.S. Drought Monitor. Sections of both northern and southern Indiana also fell back into an abnormally dry rating - a drought watch category.
That, combined with persistent drought in the western U.S., has Indiana farmers worried that the state could slip back into the same pattern. But Scheeringa said history is on our side.
"Historically, we haven't had two significant droughts back to back, in part because of our geography directly north of the Gulf of Mexico," he said. "The Gulf is a major source of our moisture and it's really hard to shut off that water supply for an extended time. Our research shows the longest Indiana droughts have lasted about 18 months. The state can have frequent minor droughts, but if they happen in the colder months the impacts are less than if they happen during the growing season."
That isn't the case in the western part of the country. With no direct path to Gulf moisture, Scheeringa said it's more difficult for the western states to break a drought pattern. Once western droughts take hold, they can last multiple years, or even a decade, as was the case recently.
"Indiana is in the eastern part of the country where drought years aren't as connected," he said.
December weather models continue to predict a wet, warmer-than-normal month around the state, although 70-degree temperatures won't continue.
"We'll be transitioning this week into cooler temperatures and rain, which may continue into mid-month," Scheeringa said.