DEKALB, Ill. — Extreme weather events had a significant
impact during 2012.
“There were 11 $1 billion disasters last year,” reported
Candice King, meteorologist with the WTVO Morning News Team in Rockford.
“It started in March with tornadoes, then there was the
extreme heat and wildfires in the West during the summer and fall, Hurricane
Isaac, Superstorm Sandy and also the drought,” recalled King during an
educational seminar at the Northern Illinois Farm Show. “And we’re still
continuing with the drought and heat — December was 8 degrees above
During 2012, King said, thousands of records for high
temperatures were broken across the U.S.
“Weather often repeats itself. It takes a while to break the
cycle and pattern,” she said.
The heat and drought during 2012 was caused by a persistent
ridge of high pressure in the middle of the U.S., the meteorologist explained.
“When you have a persistent ridge of high pressure, it’s
hard to get storms to develop,” she said. “In order to get storms to form, we
need air to rise.”
If air up above is as warm or warmer, the air at the surface
isn’t going to rise and thunderstorms won’t form.
“The drought helped to enhance the heat because if you don’t
have any moisture in the soil, a dry ground will heat up more than ground that
has moisture,” the meteorologist explained. “It doesn’t look like we’re going to
break this pattern going into the spring.”
Meteorologists look at a lot of models to put together a
“There are tons of forecast models we look at every day to
put a forecast together,” King noted. “Some are short-term, three- to five-day
period, and others cover one to three hours that we use during severe weather
Data comes from weather stations, instruments on the bottom
of airplanes, weather balloons and buoys.
“When you put together a forecast, you always go from top
down — what’s happening up above to what’s happening at the surface of a
forecast model,” the meteorologist explained.
For the surface analysis, King said she looks to see where
the high and low pressure systems are located and where the cold and warm fronts
are positioned and at the atmosphere thickness lines. At 3,000 feet, she also
looks for the high and low pressure systems and the cold and warm fronts.
“The temperatures are critical in determining where we have
warm air advection, which helps to determine the temperatures at the surface,”
“For the 18,000-feet level, low pressure systems in the
summertime can enhance a severe weather front and in the wintertime can enhance
snowfall,” the meteorologist said.
This level is critical for temperatures in the summertime,
“Because if the temperature inside the low pressure system
is really cold, that enhances the instability in the atmosphere and we can get
hail or cold air funnels,” she said.
The Artic Oscillation and the North Atlantic Oscillation are
two models used by forecasters.
“The oscillations are differences in pressure in the mid
latitudes of the atmosphere, and as those change and shift, that affects our
weather,” King explained.
Both of these oscillations have negative and positive phases
or warm and cold phases.
“The positive phase is more of a mild jet stream pattern
across the northern hemisphere,” the meteorologist said. “When you have the
negative phase, it leads to colder air coming in.”
The El Niño and La Niña patterns will impact weather, and
they have effects on the jet stream.
“If sea surface temperatures are going up over a three- to
four-month period, it’s an El Niño event,” King said. “And if sea temperatures
are going down for a three- to four-month period it’s a La Niña pattern.”
“We were transitioning this past spring, summer and fall out
of a La Niña pattern to a more El Niño pattern, where the sea surface
temperatures were beginning to warm,” she added. “So the Climate Prediction
Center issued an El Niño advisory.”
However, King noted, all of a sudden it stopped.
“They didn’t see any warming or cooling, and forecasters
said it was something they hadn’t seen before in their lifetime — it was
uncharted territory,” she said. “Technically, we are now classified as in
According to the Climate Prediction Center, King said, for
the remainder of the winter and going into spring, there is no indication that
the water near the equator will warm or cool down.
“So we’ll stay in the neutral phase,” she said.