[Nameplate] Fair ~ 81°F  
High: 87°F ~ Low: 52°F
Thursday, Oct. 8, 2015

Blame it on the jet stream

Sunday, August 22, 2010

Mike Milam
The jet stream on earth is very important because of its impact on climatic changes and because of its impact on commercial aviation. According to the Wikipedia, the jet stream on earth is caused by a combination of the earth?s rotation and solar heating. Information can be found on this phenomenon at http://en.wikipedia.org/wiki/Jet_stream.

So why is this important to us? The jet stream impacts our weather and its influences commercial aviation. The main commercial relevance of the jet streams is in air travel, as flight time can be dramatically affected by either flying with the flow or against the flow of a jet stream. The jet stream flows in an east to west direction and it resembles a snake chasing its tail.

A recent article entitled, ?Frozen jet stream links Pakistan floods, Russian fires? found online at this link, http://www.veteranstoday.com/2010/08/12/... got my attention. This article describes how the weather patterns affect the wildfires in Russia. With the drought and excessively high temperatures, the vegetation is vulnerable to wildfires. This weather pattern is also linked with the floods in Pakistan.

From personal experience, I talked with producers and family in Cross Plains, Texas about wild fires that affected that community around Christmas of 2005. On December 27, 2005, a grass/range wildfire destroyed 116 homes in and around Cross Plains. On December 29, 2005 the Texas Department of Public Safety (DPS) listed 85 single family homes, 25 mobile homes and 6 apartment units as being destroyed. An additional 36 homes were damaged. The First United Methodist Church building of Cross Plains was also destroyed. Two people died after being trapped in their houses. The fire started 5ˇmiles west of the city along Highway 36, and westerly winds of up to 30 miles per hour spread the flames into town, burning a total of 7,665ˇacres of land. I was told that the rains in late summer had resulted in excessive growth of annual grasses and shrubs. The vegetation dried out and served as an excellent fuel source to spread the fires.

The United Nations has estimated that 6 million people being affected by the Pakistan flooding. In addition to these events, a heat wave in Japan has resulted in 60 deaths. This jet stream pattern has affected the weather in Western Europe and unusual weather patterns in Canada and the United States. The excess rainfall in much of Missouri this year is also being blamed on the pattern of the jet stream. In the Missouri Crop Progress and Condition Report for the week ending August 15, the North Central and Northeast regions still have 7 and 19 percent excess moisture, respectively.

According to meteorologists monitoring the atmosphere above the northern hemisphere, unusual holding patterns in the jet stream are to blame. As a result, weather systems sat still. Stationary patterns in the jet stream are called ?blocking events?. So what do we blame for these summer blocking events? While there is speculation, one meteorologist blames it on solar activity. Earlier this year astrophysicist Mike Lockwood of the University of Reading, UK, showed that winter blocking events were more likely to happen over Europe when solar activity is low ? triggering freezing winters. He says he has evidence from 350 years of historical records to show that low solar activity is also associated with summer blocking events. ?There?s enough evidence to suspect that the jet stream behavior is being modulated by the sun,? he says.

I have written about the impact of the weather patterns for much of this cropping season. The impact of our hot dry conditions has lead to our crops being much earlier. The Crop Progress and Condition report indicated that we are 12 days ahead of last year and one day ahead of normal with 6 percent of the bolls opening. The reason for the earliness is the heat unit accumulation. From May 1- August 15 we have accumulated 2102 heat units. For comparison purposes, we have already exceeded 7 of the last eight years for accumulation through September 1.

According to the MU Guidesheet G4268, Cotton Plant Development and Plant Mapping, we should accumulate between 2150 and 2300 heat units before harvest which normally occurs around September 21. This is good news in that harvest season will begin within the next few weeks rather than late September. I have heard reports that the gins will be opening earlier this year rather than leaving the modules for later. Usually the early start will result in an earlier finish this season.

The bad news is that this heat has taken a toll on the non-irrigated crop which will reduce yield and could have an impact on micronaire. If producers are using the Hal Lewis method of to keep micronaire levels out of the penalty range, they can still take samples to the MU Delta Center for micronaire testing. The charge is $10 per sample. For more information, call Andrea Jones at the Delta Center at 573-3795431. If conditions are still dry during harvest, the dusty conditions will affect the harvest crews.

According to the Cotton and Wool Outlook for August 13, Missouri?s yield is projected to be 983 pounds per acre. This exceeds the Delta average of 956 and only Arkansas?s 1062 pound per acre exceeds it. We know that some of the irrigated cotton is exceptional and some of the non-irrigated is very poor. The yields could range from a few hundred pounds an acre to over 1500 pound per acre. At this point in the season everything we will just have to wait and see. We should have a better understanding after ginning season begins.

University of Missouri Extension programs are open to all.

Dr. Michael R. Milam is an agronomy specialist and county program director with University of Missouri Extension in Dunklin County.

At Your Service
At Your Service