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Livestock Wx for Jan. 5, 2018: Why it’s been so cold, what to expect for January, and an update on where drought is intensifying.
Why so Cold?
“If you expect to follow the trail, son, you must learn to do your sleeping in the winter.”-Andy Adams, The Log of a Cowboy: A Narrative of the Old Trail Days.
Given temperatures over the holidays, it sure has been tempting to just sleep right through it. Many of you might be asking “just why has it been so cold?” The very cold temperatures gripping large portions of North America, including the central and eastern United States has been due to a persistent wave of arctic air that has caused temperatures to drop more than 20 to 40 degrees (F) below normal in many locations, resulting in one of the coldest starts to a new year in decades.
While this is historically the coldest time of the year over many parts of the nation, this one is shattering records. For example, Aberdeen, South Dakota, dropped to a record minus 32 last Sunday morning with wind chills across parts of Montana of minus 58 degrees!
There could be several reasons why it has been so cold.
The North American Winter Dipole is a winter anomaly characterized by a northward bulging of the jet stream, and unusually warm temperatures, over the western U.S. with a concurrent dip in the jet stream and unusually cold air over the east.
The winter dipole disrupts arctic circulation patterns, resulting in a weakened Polar Vortex, and often results in intrusions of unusually cold air into the eastern U.S. Scientists at Columbia University speculate unusually warm waters over the tropical western Pacific have tended to push the jet stream unusually far north. Other research shows that there has been an increase in the number of days each winter characterized by simultaneously very warm temperatures across the west and very cold temperatures outbreaks over the east.
Patterns like this have a tendency to become self-reinforcing, lasting for much longer than more typical transient weather patterns.
Others have speculated ice loss and the Polar Vortex could be another reason for the Arctic outbreak. This is due to Arctic regions that have been warming faster than the rest of the planet. This has resulted in unusually low amounts of Arctic sea ice.
Open water can serve as a source of both heat energy and moisture evaporation into the atmosphere. This enhances snow formation downstream and can serve as a seasonal source of cold air.
Yet another reason could be low solar activity. According to NASA observations, there are currently zero sunspots. In 2017, 27 percent of the days reported zero sunspots. The sun’s output has been decreasing since the past Solar Maximum in 2012-2014.
Cycles of solar energy/luminosity are a natural occurrence. While even small decreases in solar energy can significantly reduce the amount of energy that reaches the earth—specific related weather impacts are not at all clearly understood. A report issued by the National Research Council (NRC) states that solar cycle changes can affect the chemistry of Earth’s upper atmosphere and possibly alter regional weather patterns, especially in the Pacific.
But could the recent cold snap be due to reduced solar activity?
Not likely. While the U.S. currently is experiencing the coldest anomalies of anywhere on the globe, there are plenty of spots where temperatures are above normal. While December will likely average well-below-normal for the U.S. and possibly North America, from a global perspective, there is little sign of cooling.
January Outlook
The January Precipitation and Temperature Outlook below shows the current cold pattern could last through the first half of January from the Great Plains eastward. For precipitation, the odds are slightly tilted to below normal for a large portion of Texas south of I-20, while northeast Oklahoma has a slight chance of above normal precipitation.
Dryness Continues from OK Panhandle Down to West-Central TX
Since the first of October, the percentage of drought in Texas has increased by 30 points while Oklahoma has seen an increase of more than 60 points. Based on this week’s Drought Monitor, more than 75 percent of Oklahoma and approximately 32 percent of Texas is in some form of drought (D1 or greater). The most recent increases have been in the TX-OK Panhandle and down into the Plains.
That’s it for this week. If you have any questions about conditions around Texas and Oklahoma please contact us at [email protected]