Will La Niña have negative impact on '18 growing season?

Colleen Kottke
Wisconsin State Farmer

La Niña, the cooler sibling of El Niño, is here.

The La Niña climate pattern — a natural cycle marked by cooler-than-average ocean water in the central Pacific Ocean — is one of the main drivers of weather in the U.S. and around the world, especially during the late fall, winter and early spring.

This is the second consecutive La Niña winter. Last year's episode was unusually brief, forming in November and gone by February. DTN Senior Ag Meteorologist Bryce Anderson said this year's La Niña is on the weak side, but it should still continue through the winter.

Anderson provided his meteorological insight during the Midwinter Weather Update webinar on Jan.16.

Typical impacts of a La Nina winter across North America.

La Niña is a climate pattern marked by cooler than average water in the central Pacific Ocean and has a big impact on the snowfall in the winter. Farmers are watching this weather pattern closely and its potential impact on crop production around the world.

Anderson expects waters in the equatorial region to see a warming trend by late spring into early summer creating a neutral phase.

"It doesn't look like the water temperatures in the Pacific are going to be of the type that supports a real harsh temperature and dryness pattern over the major crop areas of the U.S. this year, particularly in the Midwest," he said. "I'm not looking for an onset of a real extensive drought over the Corn Belt in 2018, as the neutral phase is likely to dominate the scene as we go through the balance of the year."

Bryce Anderson

Remaining winter forecast

A typical La Niña winter in the U.S. brings cold and snow to the northwest and unusually dry conditions to most of the southern tier of the U.S., according to the Weather Prediction Center.

Anderson said La Niña opens a pathway for northern air to cover most of the north and central U.S.

"We have certainly seen that as we head into mid-winter. Another feature that has contributed to the kind of chill we've had is the revisiting influences of the polar vortex from the far northern latitudes," Anderson said. "When that happens the colder conditions in the far north do have a chance to move further south as we've seen the past couple of weeks."

With this in mind, Anderson says the entire northern tier of states west of the western Great Lakes all the way to the Pacific Northwest will likely see frequent cold, enhanced snowfall and a longer lasting winter season.

"The reason this is so important is we're looking at a slower start to the spring and spring fieldwork in the Northern Plains, northern Midwest and Pacific Northwest," Anderson said.

Niagara Falls State Park visitors look over masses of ice formed around the American Falls, photographed from across the Niagara River in Canada during the Polar Vortex event in Feb. 2015. For many cities in the Northeast, it was the coldest February on record.

The New England states which have seen their share of icy weather this winter will experience a warming trend with quite a bit of precipitation, Anderson said, adding that the last cold snap froze up the Niagara Falls in Buffalo, NY. 

"I wouldn't be surprised if we have several more ice storms development in the ares with that colder air still likely to bring some incursion for the balance of winter on into the spring," he said.

Saving grace

While many in the Midwest experienced a slow start to the 2017 planting season, especially in Wisconsin, Anderson said last year's above normal temperatures in parts of the Corn Belt from central Iowa into the Dakotas raised concerns of reduced corn and soybean yields.

"Heading into August temperatures throughout the entire central U.S. were below normal, which allowed the fill stage of corn and soybeans to have an extended period. It also allowed crops to make use of available soil moisture," he said. "That was a really big factor in terms of allowing yields to achieve the levels that they did."

Mild temperatures returned in September and Anderson said that late freeze dates also helped to keep the season going; even replanted acreage caught up in terms of crop development."

Anderson says there's a real possibility that a cooler August may save crops once again this year.

"It's a real possibility and last year it was a real saving grace," he said, "because crops were working off available soil moisture from the first of July clear to the middle of August."

Farmer John Weinand surveys wheat in a field near Beulah, N.D. Drought in  North Dakota during the summer of 2017 had a devastating impact on crops.

Drought conditions

According to the U.S. Drought Monitor, there were several particularly dry areas across the U.S. including the southwest Plains states, Texas panhandle, and southern Midwest to name a few.

"The northern plains drought is showing maybe a little bit of improvement in Montana but over the western Dakotas, I don't think we're going to see much improvement with storm systems not lasting long enough to bring an appreciable amount of snowfall," Anderson said.

The meteorologist said dry areas in the Midwest were likely to see better conditions except for portions of central Illinois.

"A lot of the central and eastern Midwest is likely to stay out of a drier pattern going into the rest of 2018," he said.

U.S. Winter Outlook for precipitation

Weather Outlook

Using comparable analog weather models from the years '63, '67, '85, '89 and '06 —where a weak to moderate La Niña weather pattern evolved into a neutral phase — Anderson presented forecasts for the 2018 growing season for the Midwest.

Moving forward from a cold March, Anderson said the month of April will experience a fair amount of warming but not a lot of precipitation.

"When you think about the implication for fieldwork, if April were to have that tendency there would be at least a shot at a normal start for spring fieldwork over much of the primary crop areas," he said.

Cooler temperatures will usher in the month of June with the Midwest becoming a "little bit dry". While the northwest will see very warm to hot conditions during July, Anderson said milder conditions will prevail over the remainder of the Midwest. August is projected to be cooler, which Anderson said may be a repeat of 2017. 

Anderson noted that the NOAA forecast calls for near to above normal temperatures for the Midwest with above normal precipitation.

Crop Prospects

Anderson said crop conditions across the U.S. will be variable.

"I do think that some sectors of the Corn Belt will have a tough time getting the kind of yield growers like to see due to the residual dryness following the drought last year and in the southern plains its the same deal," he said. "However, this is not a scenario like the 2012 crop year where I was really concerned about dry conditions spread across a large part of the country."

Soybeans grow in a farm field near Indianola, IA, during the summer of 2017. At the time, the weekly U.S. Drought Monitor noted that nearly 11 percent of the continental United States is in moderate drought or worse.

The corn and soybean harvests for South America are shaping up to be productive, Anderson said. Already Brazil has increased its soybean production estimates to 110 million metric tons, with corn production estimated at 92 million tons.

Argentina experienced a dry early spring. The South American country is the world’s third largest exporter of corn and soybeans. Anderson described the country's soil moisture patterns as "patchwork conditions".

"Hopefully they will have enough to bring the crops to the end of the season in good shape," he said.

Anderson said soil moistures in Russia and the Ukraine have improved immensely since the drought in 2010, helping both growing areas to flourish.

"They've built a big export grain facility in a southern port on the Black Sea. With a warming climate the port is not freezing as much as it used to so they have a longer shipping season," he pointed out. "Russian production has increased and they simply have more to sell."

Doyle Rice contributed to this story.