FARGO, N.D. -- How long will the remnant effects of the La Nina let go and El Nino take over?
That's the question North Dakota State Climatologist Adnan Akyuz wrestles with as he attempts to make sense of the climate data. He's been trying to answer a big question -- when will a killing frost hit the region?
"We are coming out of a very cool season, which relates to a strong La Nina, which started two years ago and ended about six months ago," Akyuz says.
La Nina is the cooling of ocean surface temperatures in the eastern equatorial Pacific Ocean, which correlates to weather changes in the Midwest and elsewhere.
"Even though the summer was considered 'neutral,' we're still seeing remnants of the past strong La Nina, which brings the cooler-than-normal summers," Akyuz says.
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Now, however, there are changes in the ocean surface temperatures between the 5 degrees North and 5 degrees South range which indicate a new trend -- El Nino.
"It is expected that the winter is going to show signals for El Nino," Akyuz says. "Normally, when that happens, eastern North Dakota will experience a warmer-than-normal temperature in the winter, and drier than normal. You have two natural forces working against each other, which makes conditions interesting."
Akyuz thinks the persistence of La Nina effects will win out in its effect on 2009 frost times. Why? El Nino's effects are more pronounced in the in the wintertime and not so much in the fall, Akyuz says.
Based on growing degree units Akyuz sees the maturity dates for corn in Fargo at Oct. 19. And -- based on history -- there is a 90 percent probability that a killing frost will occurred before that date.
And now some good news: Akyuz says national weather officials on Sept. 1 predicted that eastern North Dakota has a good chance of receiving above-normal temperatures from the Sept. 6 to 10.
The meteorological or weather forecasts are running counter to the long-term climate data for the moment.
"It's only a four-day period, but at this time, farmers are really crunching small numbers to make big differences," Akyuz says. "The maturity date may be a few days earlier, meaning a less chance that the killing frost prior to that time."
Climate correlations are handy to making long-term .
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"We are so close to the end of the season, allows us to use the metorological forecast, which has a higher probability of coming true," Akyuz says.
