Despite moderate to strong La Nina conditions, meteorologists are not predicting drought for the 2008 growing season. But they do say more variability is ahead, both in temperature and precipitation.
Abnormally wet conditions are expected to persist through March and much of April for the eastern Midwest areas of Michigan, Ohio, Indiana and Illinois stretching into southern Missouri and Arkansas, says Fred Gesser, Senior Meteorologist at Planalytics, a weather forecasting company in Wayne, PA. The company gave its spring outlook on March 6.
In the Corn Belt, cooler temperatures and persistent rain in southern and eastern areas may slow the drying process and possibly delay planting. Then look for an abrupt swing to above normal temperatures for April and May.
Temperatures for the rest of March will be above normal in the southwest, below normal in the north and average everywhere else, says Gesser. Precipitation will range from drier than normal from Arizona up into Minnesota, to wetter than normal from eastern Oklahoma up through Maine, cutting through much of the central and eastern Corn Belt.
Winter wheat emerging in wet conditions in March and April could prompt disease and pest infestations for Michigan, Ohio, Indiana and Illinois.
For April Gesser forecasts temperatures to be above normal from the western Corn Belt to Ohio including Missouri and Minnesota, and below normal in the west.
For May the meteorologist predicts above normal temperatures stretching across the Corn Belt including Oklahoma, all the way into New York, with below normal temperatures in the northwest. He forecasts dry conditions in the Northwest over into Minnesota, and dry conditions along the eastern seaboard. Most of the Corn Belt, southeast and southwest should experience adequate moisture.
Will we see a last-minute switch to soybeans if persistent wetness holds in the eastern Corn Belt? It's possible provided there is enough seed available. The decision to switch from corn to soybeans involves fertilizer applications, rotations and current prices, as well as weather delays and seed supplies.
The outlook for spring in the northern Corn Belt states of Minnesota, South Dakota, North Dakota and Wisconsin, as well as parts of Nebraska and northwest Iowa, is persistent dry conditions. That may present opportunities for early plantings. It could also lead to drought conditions if the trend holds into June, says Gesser.
Persistently cold equatorial sea surface temperatures had meteorologists proclaiming a moderate to strong La Nina event as of the end of January. The U.S. has experienced six such La Ninas in the past 60 years. Most of the current forecast models show this La Nina episode to continue through the fall of 2008.
However, the past winter offered clues that this is no ordinary La Nina. Past events brought extreme drought in the southwest, but December rainfall totals there were 300 to 600% higher than normal. Over this last winter California has had 110% of its normal moisture.
In addition, the Southeast U.S. has had a winter-long pattern of active precipitation — including two more storms in mid March. That's not typical of La Nina, says Gesser.
The Corn Belt states of Indiana, Illinois, Ohio and Michigan experienced 150 to 300% more precipitation than normal this winter. "It's going to get wetter before it gets drier in the Midwest," says Gesser.
On the other hand, this winter Iowa, Missouri and Nebraska have had 50 to 70% less precipitation than normal.
"Not every El Nino or La Nina episode produces the same weather pattern across all of North America," Gesser concludes. "Every one of them has its differences