Favorable Weather Forecast For Rest Of 2009 Growing Season

ISU Extension climatologist Elwynn Taylor says if El Nino kicks in, it would be good news for yields in Corn Belt.

Iowa has had a wet summer so far, and a hot spell in June. We've had some cooler than normal weather too. However, the 2009 growing season has certainly been better than the historic flooding of a year ago. What does Iowa State University Extension Climatologist Elwynn Taylor think of this growing season's weather? What does he predict lies ahead for the rest of this summer?


For most of Iowa, 2009 has been a picture-perfect growing season so far, and Taylor sees no changes for July and August—except it may be a tad drier. The summer forecast for the Corn Belt is about as near ideal as possible suggesting a cooler than normal summer which helps both corn and soybean production.  http://www.cpc.noaa.gov/products/predictions/30day/

Taylor says El Nino is a possibility (not a forecast) by Mid-August, oppressively high temperatures are then avoided and corn and soybeans flourish. 


Iowa crops in good to excellent shape overall


"There are a couple of things to consider, a couple of indicators that we are watching," says Taylor. "Yes, 2009 is better than last year. And the USDA weekly weather and crop condition surveys that came out the past two weeks show Iowa's corn and soybean crops are in mostly good to excellent condition overall. So that is positive, at least to date. We can hope this situation continues."


The latest National Weather Service Forecast as of July 6 indicates drier than usual weather over much of the Corn Belt for the next two weeks. Also, this same forecast indicates weather for the rest of July and into August may be on the cool side of normal. "If cooler than normal weather is indeed what we end up getting, then the drier than usual conditions would not be a setback for corn and soybean crops," he notes.


If El Nino occurs, it would be good news for yield


"We'll be watching this weather situation quite closely," says Taylor, "because a drier than usual forecast always gets our attention. With that type of a forecast, we don't know how likely it is to turn out to be true, but it is something to consider. We have a couple of other weather indicators we're watching. For example, there has been a tendency to move toward an El Nino event this year. That is considered good news for the Corn Belt. But at the moment, nothing is happening with the El Nino situation in the summer of 2009. We can't tell yet if our weather is moving toward an El Nino or away from it this summer."


Taylor and other weather experts will continue watching the warming waters of the Pacific Ocean to see if an El Nino event develops.


Meanwhile July, August and September are forecast by some well-known private weather experts to have a slight chance of being on the dry side of normal for the Corn Belt. The odds are a 60% chance of the Corn Belt being slightly drier than usual. "A drier than normal forecast is usually not good news for farmers and crop yields," says Taylor. "But if we stay on the cool side of normal during this period, it's not bad news either."


What about the date of the first fall frost? When will that occur? Taylor says the date of the first killing frost in the fall is virtually impossible to predict with any accuracy. In some years the cold weather is held to the north, and then the atmosphere breaks down suddenly and you can have a freeze dropping down into the Corn Belt very quickly from the north in early September. However, if you have a cool growing season during the summer, that would reduce the odds of a real cold snap coming down early in the fall, he notes.


If El Nino occurs, expect normal or later than normal frost


"We can't predict with very much accuracy whether or not we'll have an early frost or a late frost in the fall," says Taylor. "We can anticipate however that if we should move to an El Nino condition this summer--that would do a lot to decrease the odds of an early frost coming our way here in the Corn Belt. But right now (as of July 10) El Nino is in neutral so we have to say we expect 2009 to be an average year in terms of the weather outlook for the rest of the growing season."


Last year Iowa had a late planted, and late maturing corn crop and soybean crop. This year the forecast is for a cool 2009 last-half of the growing season. That's fine in terms of crop development. "The corn will grow even if you have a cool growing season, if you couple it with some nice rainfall. But if we don't have a late frost this fall, then a cool growing season isn't good news," adds Roger Elmore, an Iowa State University Extension corn agronomist.


"That's because If we end up having a cool growing season this summer and it slows this year's crop maturity down, then we'll need to have a later than normal killing frost this fall," says Elmore. "A later than normal fall frost date would allow the crop to mature properly."

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