Candice King, meteorologist with the WTVO Morning News Team in Rockford, Ill., presents an educational seminar at the Northern Illinois Farm Show.
Candice King, meteorologist with the WTVO Morning News Team in Rockford, Ill., presents an educational seminar at the Northern Illinois Farm Show.

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 average.”

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 weather forecast.

“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 events.”

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,” she added.

“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, King noted.

“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 neutral.”

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.