Weather service upgrade will boost forecast accuracy

Brian Nieuwenhuis prepares to release a weather balloon Tuesday at the National Weather Service office in Medford. Starting today, the balloons, which are launched twice a day, will contain a new piece of radio technology that will increase their forecasting ability. Mail Tribune / Julia MooreJulia Moore

The National Weather Service office in Medford is upgrading a key piece of equipment meteorologists use to gather weather data, a move officials say will result in more accurate forecasts.

The upgrade comes in the form of tiny sensors called radiosondes. The devices are attached to weather balloons, which are launched twice a day. During a 90-minute ascent to an altitude of about 100,000 feet, the sensors transmit data back to NWS computers.

Tracking the weather

Before the advent of compact radio technology, the only aspect of weather meteorologists could track using balloons was wind speed.

Watching from the ground while using a telescope or binoculars, weather officials would track a balloon's movements and measure the wind speed that way.

"Before GPS, you had to track it by eye," said National Weather Service meteorologist Brian Nieuwenhuis.

He said the Medford office still has a stand on its roof that meteorologists used to mount telescopes while they tracked balloon movements across the sky. It hasn't been used in quite a while, said meteorologist Mike Ottenweller.

Over time, compact radios — sondes — were attached to weather balloons, and they broadcast data on wind speed, temperature and humidity, but weather officials had to record the incoming information by hand.

"(Now) it all comes in to a computer, and the computer spits out the information that we need," Nieuwenhuis said.

In addition, a GPS system means weather officials don't have to track the balloons by sight.

The newest radiosonde upgrade broadcasts data about every one-sixth of a second as the balloon carrying it ascends into the sky. Meteorologists launch the devices twice a day. Under special circumstances, such as the recent landfall of superstorm Sandy, they'll launch more.

"Just so there was extra data for the models," Nieuwenhuis said.

The new devices are less expensive to manufacture and are made with closed-cell batteries, which lessens the impact on the environment when the devices land, Nieuwenhuis said.

"It will take temperature, the relative humidity and the pressure," said NWS meteorologist Mike Ottenweller.

The Medford office was one of 24 NWS locations in the U.S. to receive the new radiosondes — out of 102 stations in North America, the Pacific Islands and the Caribbean, and more than 800 locations worldwide. The award was based on the Medford station's history of forecast accuracy and its proximity to the Pacific Ocean.

"We're kind of the entry point for these systems that are going to affect the rest of the United States," Ottenweller said.

Where the old radiosondes transmitted data every second or so, the new RS-92 model broadcasts every one-sixth of a second.

"The whole system is designed to eliminate any errors," Ottenweller said.

After reaching the peak of its ascent, the weather balloon bursts. A small parachute opens and carries the radiosonde back to earth. The devices typically land somewhere east of the Cascades, Ottenweller said. A prepaid mailing envelope is attached to each transmitter, which finders can use to send the device back to NWS offices. The radiosondes cost $250 each, but only about 20 percent of them are returned nationwide. Locally, that rate is even lower.

"There's so much wilderness in the surrounding area," said meteorologist Brian Nieuwenhuis. "They land out in the middle of nowhere and nobody will find it."

Locations for the few balloons that have been found and returned include Klamath Falls, Bonanza, Grizzly Peak and spots around the Siskiyous.

The inaugural launch for the new radiosondes will be at 3 p.m. today. "We're very much looking forward to being part of this Phase 2 to gather information more accurately, more effectively," Ottenweller said. "We're very excited to be transitioning."

Reach reporter Ryan Pfeil at 541-776-4468 or

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