Storm Week: Severe Drought - KAUZ-TV: Newschannel 6 Now | Wichita Falls, TX

Storm Week: Severe Drought

Many people believe severe weather has to come in the form of thunderstorms and tornadoes.  However, the definition of severe weather is weather that has major impacts on society.

Over the last three years, Texoma has been hit hard by a crippling drought.  Lake Arrowhead and Kickapoo are nearly dried up causing the city of Wichita Falls to implement its toughest water use restrictions ever.

We haven't come close to average rainfall since 2010.
2010 28.98 inches
2011 12.97 inches
2012 19.81 inches
2013 21.33 inches
Average 28.92 inches

The oceans can actually be a big player in our climate, and both the Pacific and Atlantic Oceans are working against us. 

"The Pacific Decadal Oscillation is in the negative phase, which tends to lead to dry conditions in the winter time.  The Atlantic Ocean has been running kind of warm for the past couple decades and that tends to lead to drier conditions in the summer time," said Texas State Climatologist, who helps produce the Texas State Drought Monitor, Dr. John Nielsen-Gammon.

An oscillation is the back and forth motion of something.  The Pacific Decadal Oscillation characterizes the change in temperatures close to the ocean's surface in the northern part of the Pacific Ocean.  The Atlantic Multidecadal Oscillation is the change of sea surface temperatures in the Atlantic Ocean.  If the oscillations are in a negative phase the oceans are cooler. If they are in a positive phase the oceans are warmer.  These cycles usually last about 60 to 70 years. 

"Both of them have been in the unfavorable configuration since the late 1990s to the beginning of the 2000s.  So, they are going to be unfavorable for about 30 year's maybe we are about half way through," said Nielsen-Gammon.

Northern Pacific and Atlantic Ocean temperatures are just part of the climate puzzle.  Another piece of the puzzle is the temperatures in the southern pacific, which can change on a yearly basis.

"La Nina tends to be dry conditions and El Nino tends to be wet.  We've basically had La Nina or neutral conditions for the past three years so that's been favoring dry conditions," said Nielsen-Gammon.

During a La Nina, strong winds near the equator push warmer water away from the coast of Central and South America.  Colder water replaces it, which tends to lead to a blocking area of high pressure off the coast of North America.  This type of weather pattern tends to move the jet stream away from Texoma resulting in drier conditions. 

An El Nino is the exact opposite, weaker winds near the equator allow warmer water to remain near the coasts of Central and South America.  The warmer water does not favor the blocking area of high pressure.  The jet stream is then morel likely able to move right over us increasing our chances for rain.

"Right now, all of the forecast models are pointing towards a good chance of an El Nino which will be good," said Nielsen-Gammon.

But an El Nino does not automatically mean our drought is going to end.  Nielsen-Gammon said ocean currents can only alter the weather.  They do not drive it.

"Really the way things are aligning the next year or so is going to determine if this is one of the moderate periods of drought or one of the long ones like the 1950s.  If we get an El Nino year next year and it is still dry then we have to look forward to La Nina and have to go through that cycle again before we recover," said Nielson-Gammon.

However, our drought problems won't disappear when this drought ends.  History has shown us that droughts occur from the affects of hot temperatures and low rainfall.  Since the 1970s, temperatures have been going up and they have been rising faster than most of the climate models have predicted.

Nielsen-Gammon said the warmer temperatures are going to increase evaporation rates and water demands so we are going to need more rainfall to maintain our lake levels.

"Rainfall is a really big question mark going forward for Texas because the computer models have a bit of variability.  They tend to predict a slight drying yet over history over the past 100 years there has been an increase in rainfall even if you include the current drought," said Nielsen-Gammon.

History has shown us it takes awhile to get into a drought but only a short time to get out of one.  However, predicting a flood several months in advanced is nearly impossible.

Nielsen-Gammon said it tends to be really hard to get a continuous drought in Texas.  The drought we are in now is about the third longest one we have seen since weather records began.  So, odds are it is going crack. We just do not know when.

James Parish, Skywarn 6 Meteorologist 


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