With a cold front moving into the region this week, farmers are watching the impact on their crops, a South Dakota official says.
Daytime temperatures are forecast to plummet from a predicted high of 83 degrees today (Monday) to 53 degrees Thursday. Meanwhile, overnight lows are forecast to plunge to 44 degrees Wednesday and 38 degrees Thursday.
Crops should have received enough heat units—the accumulated degrees of warmth—to make it through the cold snap, according to South Dakota state climatologist Dennis Todey.
“For most producers, the concern now is how much more heat in the fall and when the freeze comes,” he said. “Down in (the Yankton) area, most people should be OK unless something odd happens with a freeze. There are a few folks who either planted late or replanted, and they’ll lose acres. But that shouldn’t be widespread.”
Southeast South Dakota and northeast Nebraska have experienced a cool, wet summer, Todey said. August and early September have produced warmer days, helping with crop maturity, he added.
However, conditions will reverse with the arrival of the new weather front.
“We’re watching this cold pool coming south the end of the week,” he said. “Your area (around Yankton) shouldn’t have a problem other than being cold.”
The National Weather Service (NWS) calls for the cold front allowing for additional thunderstorms.
The best chance for severe storm activity will likely occur late Tuesday afternoon and evening. Large hail and strong winds appear the largest hazards. However, locally heavy rain appears possible as well.
Tuesday afternoon, the incoming system could produce an isolated severe storm toward Sioux Falls and Yankton.
The NWS forecast calls for 80 percent chance of thunderstorms Tuesday and 70 percent chance of showers Tuesday night, dropping to 40 percent Wednesday and 30 percent Wednesday night and Thursday.
The seasonal change raises new concerns about heat units and growing-degree days, the warmth accumulated during a growing season. A growing-degree day isn’t the same as a 24-hour day. Instead, the figure provides a measure of crop maturity between planting time and the first killing frost. For example, corn develops faster during warmer temperatures and slower during cooler temperatures.
Growing degree days are calculated by subtracting a base temperature from the average of the maximum and minimum temperatures for the day, according to South Dakota State University (SDSU). Corn doesn’t grow much at temperatures of 50-55 degrees, so 50 degrees is often used as the base temperature for corn. On the other hand, 86 degrees is often used as the maximum temperature.
The sum of these “heat units” for each calendar day of the growing season provides a figure ranging from 2,300 to 3,000 in South Dakota, according to SDSU officials. The figure helps pin down the maturity period or rating of corn.
Yankton’s season consists of approximately 3,000 growing degree days. The figure is based on May 2 planting and the Oct. 19 average date for the first killing frost, when the temperature drops to 28 degrees half the time.
According to the NWS, last Saturday’s heat unit readings were running 111 growing degree days ahead of normal for Norfolk and 7 growing degree days ahead of normal for Sioux Falls, the closest reporting stations for Yankton.
Looking ahead, the University of Nebraska-Lincoln is forecasting a banner harvest for the Husker State. Corn and soybean progress are near average with slightly more than 70 percent of both crops in good to excellent condition.
“Dryland and irrigated yields are likely to be well above average at a majority of sites,” the report said. “While the risk of an early-killing frost is high at northern locations in the Corn Belt, the projected yield impact has diminished during the last two weeks due to warmer temperatures.”
The cool, wet summer could lead to crop moisture issues, according to Laura Edwards with SDSU Extension.
“Our long-term trends in the fall season show later freeze dates and wetter climate for September through November,” she wrote. “This could mean that high moisture crops may be a concern this harvest as delayed growth and maturity has been reported across the cropping areas this year.”
The upcoming cold snap doesn’t necessarily mean an early freeze, Edwards said.
“As for the most popular question: Will the hard freeze occur?” she said. “It’s too early to say for sure, but we don’t expect it anytime in the next couple of weeks.”
With two weeks remaining for summer, 2014 will already go down as one for the record books, Todey said.
“Your summer (in Yankton), from June through August, had five days at 90 degrees or above,” he said. “That’s the second lowest number on record after 1992.”
Most of the summer remained cooler than normal for the Yankton region, Todey said.
“The summer average temperature was 70.7 degrees, the 16th coolest on record,” he said. “Oddly, the August temperature was right close to average at 72.5 degrees, just 0.4 degrees below average.”
The summer also produced high rainfall totals, Todey said.
Yankton recorded 18.16 inches of precipitation this summer, third most behind 2010 and 1944. In addition, Yankton recorded 4.45 inches in August, the 22nd wettest on record and 1.48 inches above average.
With the moisture, the most recent U.S. Drought Monitor report shows no dry or drought conditions in southeast South Dakota and northeast Nebraska.
You can follow Randy Dockendorf on Twitter at twitter.com/RDockendorf. Discuss this story at www.yankton.net.
Daytime temperatures are forecast to plummet from a predicted high of 83 degrees today (Monday) to 53 degrees Thursday. Meanwhile, overnight lows are forecast to plunge to 44 degrees Wednesday and 38 degrees Thursday.
Crops should have received enough heat units—the accumulated degrees of warmth—to make it through the cold snap, according to South Dakota state climatologist Dennis Todey.
“For most producers, the concern now is how much more heat in the fall and when the freeze comes,” he said. “Down in (the Yankton) area, most people should be OK unless something odd happens with a freeze. There are a few folks who either planted late or replanted, and they’ll lose acres. But that shouldn’t be widespread.”
Southeast South Dakota and northeast Nebraska have experienced a cool, wet summer, Todey said. August and early September have produced warmer days, helping with crop maturity, he added.
However, conditions will reverse with the arrival of the new weather front.
“We’re watching this cold pool coming south the end of the week,” he said. “Your area (around Yankton) shouldn’t have a problem other than being cold.”
The National Weather Service (NWS) calls for the cold front allowing for additional thunderstorms.
The best chance for severe storm activity will likely occur late Tuesday afternoon and evening. Large hail and strong winds appear the largest hazards. However, locally heavy rain appears possible as well.
Tuesday afternoon, the incoming system could produce an isolated severe storm toward Sioux Falls and Yankton.
The NWS forecast calls for 80 percent chance of thunderstorms Tuesday and 70 percent chance of showers Tuesday night, dropping to 40 percent Wednesday and 30 percent Wednesday night and Thursday.
The seasonal change raises new concerns about heat units and growing-degree days, the warmth accumulated during a growing season. A growing-degree day isn’t the same as a 24-hour day. Instead, the figure provides a measure of crop maturity between planting time and the first killing frost. For example, corn develops faster during warmer temperatures and slower during cooler temperatures.
Growing degree days are calculated by subtracting a base temperature from the average of the maximum and minimum temperatures for the day, according to South Dakota State University (SDSU). Corn doesn’t grow much at temperatures of 50-55 degrees, so 50 degrees is often used as the base temperature for corn. On the other hand, 86 degrees is often used as the maximum temperature.
The sum of these “heat units” for each calendar day of the growing season provides a figure ranging from 2,300 to 3,000 in South Dakota, according to SDSU officials. The figure helps pin down the maturity period or rating of corn.
Yankton’s season consists of approximately 3,000 growing degree days. The figure is based on May 2 planting and the Oct. 19 average date for the first killing frost, when the temperature drops to 28 degrees half the time.
According to the NWS, last Saturday’s heat unit readings were running 111 growing degree days ahead of normal for Norfolk and 7 growing degree days ahead of normal for Sioux Falls, the closest reporting stations for Yankton.
Looking ahead, the University of Nebraska-Lincoln is forecasting a banner harvest for the Husker State. Corn and soybean progress are near average with slightly more than 70 percent of both crops in good to excellent condition.
“Dryland and irrigated yields are likely to be well above average at a majority of sites,” the report said. “While the risk of an early-killing frost is high at northern locations in the Corn Belt, the projected yield impact has diminished during the last two weeks due to warmer temperatures.”
The cool, wet summer could lead to crop moisture issues, according to Laura Edwards with SDSU Extension.
“Our long-term trends in the fall season show later freeze dates and wetter climate for September through November,” she wrote. “This could mean that high moisture crops may be a concern this harvest as delayed growth and maturity has been reported across the cropping areas this year.”
The upcoming cold snap doesn’t necessarily mean an early freeze, Edwards said.
“As for the most popular question: Will the hard freeze occur?” she said. “It’s too early to say for sure, but we don’t expect it anytime in the next couple of weeks.”
With two weeks remaining for summer, 2014 will already go down as one for the record books, Todey said.
“Your summer (in Yankton), from June through August, had five days at 90 degrees or above,” he said. “That’s the second lowest number on record after 1992.”
Most of the summer remained cooler than normal for the Yankton region, Todey said.
“The summer average temperature was 70.7 degrees, the 16th coolest on record,” he said. “Oddly, the August temperature was right close to average at 72.5 degrees, just 0.4 degrees below average.”
The summer also produced high rainfall totals, Todey said.
Yankton recorded 18.16 inches of precipitation this summer, third most behind 2010 and 1944. In addition, Yankton recorded 4.45 inches in August, the 22nd wettest on record and 1.48 inches above average.
With the moisture, the most recent U.S. Drought Monitor report shows no dry or drought conditions in southeast South Dakota and northeast Nebraska.
You can follow Randy Dockendorf on Twitter at twitter.com/RDockendorf. Discuss this story at www.yankton.net.
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