91探花 atmospheric scientist Lynn McMurdie has led campaigns to measure rain and snowfall in places ranging from Washington鈥檚 Olympic Peninsula to Argentina to the Eastern U.S. Now she鈥檚 among the leaders of a field campaign in Colorado to better understand and forecast snowfall in the mountains of the Western U.S.

A scientific expedition this coming winter in Colorado’s Yampa Valley will improve forecasts of snowfall and estimates of how climate change will impact snowpack and water availability in mountainous regions of the West.

, a research professor of atmospheric sciences at the UW, is one of the principal investigators on the effort, with a $4.8 million grant from the National Science Foundation and led by the University of Michigan. Other participating institutions include the University of Wisconsin, the University of Utah, Colorado State University and Stony Brook University.

The Snow Sensitivity to Clouds in a Mountain Environment experiment, or S2noCliME, will use several radars and snow-sampling instruments to measure the size and shape of snowflakes and aerosol particles. The resulting data will help estimate water availability in the Yampa Valley in northwest Colorado. This area on the northwest side of the Rocky Mountains feeds the Yampa River, the largest free-flowing tributary of the Colorado River. Like Western Washington, it relies on melting snow for its summer water supplies, and faces drought and wildfire risk when these snow reservoirs are lower than normal.

鈥淲e hope that our data will ultimately improve winter storm forecasts and tell Western cities when to expect a drought because of insufficient snowpack,鈥� said lead investigator聽, an assistant professor at the University of Michigan.

The team will deploy instruments in the Steamboat Springs region of Colorado鈥檚 Park Range, a section of the Rockies that extends from southern Wyoming to northwestern Colorado and is poorly covered by the National Weather Service radar network.

Today鈥檚 models of snowfall often struggle in these types of mountainous areas.

鈥淚n the West, our forecasting models and satellite estimates of precipitation really underpredict snowfall and often don鈥檛 get the distribution right,鈥� McMurdie said. 鈥淭he western U.S. depends on snowpack accumulated during the winter for summer water supply for agriculture, fisheries and municipal water sources. Accurate snowfall prediction and understanding the underlying processes producing mountain snow are critical in order to provide guidance on water availability.鈥�

Collecting data over an entire winter will provide the statistical power necessary to more accurately predict snowpack after winter storms and over longer timescales. Data will also be shared directly with the , a working group that brings together scientists and local water managers.

By combining snow-sampling instruments with radars that indirectly study snow, the researchers will overcome a major challenge of using radar: It鈥檚 hard to connect the reflected radar signal with the size, shape and number of snowflakes, which determines the amount of water in the snow.

The team鈥檚 radars at will use multiple frequencies for detecting snowflakes of different sizes. At the same time, the team will deploy a portable in Hayden, Colorado. This radar鈥檚 view toward and the surrounding 62 miles will be combined with the National Weather Service鈥檚 radars to see how the strength of the storms change as they move from the west toward the Rockies.

The results will be compared with those from earlier projects in the Pacific Northwest, such as the UW-led project.

鈥淲e expect to have some similarities, such as how upstream conditions affect the snow-producing cloud processes during this campaign, as well as some differences since the Colorado region is much drier and more interior than the Olympic Mountains or the Cascades,鈥� McMurdie said.

, an affiliate 91探花faculty member and former 91探花postdoctoral researcher who is now a faculty member at the University of Wisconsin-Madison is another of the project鈥檚 lead investigators. , research associate professor of atmospheric sciences at the UW, a 91探花postdoctoral researcher and one or more 91探花graduate students will also participate in the campaign.

The first instruments will arrive at Mt. Werner this summer, and the team will begin collecting measurements in December.

For more information, contact McMurdie at lynnm@uw.edu. This article was adapted from a University of Michigan .

Snowstorms can wreak havoc across the United States, but especially on the East Coast. Snow is the least-understood form of precipitation, with major snowstorms among the most difficult weather events to forecast. Yet people rely on these forecasts to stay safe, plan travel routes and decide whether to close schools or businesses.

To better understand large, disruptive snowstorms, a 91探花 atmospheric scientist will lead a NASA field campaign this winter to fly through major snowstorms along the East Coast. The multi-institutional team will observe snow as it forms in clouds to help with satellite monitoring of snowfall and ultimately improve forecasts.

“In a big snowstorm, the snow is not evenly distributed. Some places really get hammered, but others, even close by, don’t get nearly as much. We want to understand the processes behind that,” said principal investigator , a 91探花research associate professor of atmospheric sciences.

The NASA Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Storms, or campaign, will be based at NASA’s Wallops Flight Facility on the Virginia coast. The six-week campaign runs Jan. 15 through late February 2020, with additional campaigns in the same region in the winters of 2021 and 2022.

“Winter clouds contain regions that generate more snow, called snow bands,” McMurdie said. “We hope to understand why these snow bands form, and how they evolve with the developing storm. If we can understand the processes in the clouds, we can better predict how they distribute snowfall to us on the ground.”

IMPACTS is the first field campaign to study East Coast snowstorms in 30 years, and the most comprehensive study of Northeast snowstorms to date.

McMurdie led a previous NASA field campaign in 2015 that measured rain and snow over Washington state’s Olympic Peninsula. That effort focused mostly on rain over mountainous terrain; this one will focus on snow, and over relatively flatter terrain. On the Eastern Seaboard, the combination of cold air from Canada and moisture from the Atlantic Ocean can produce major snowstorms that stretch from Georgia to Maine.

“Over the course of three years, we need at least six good storms,” McMurdie said. “We expect far more, but they might not be good storms. And we want some redundancy to make sure we have all the instruments working during those events and to sample of a variety of storm intensities.”

Two aircraft will collect observations. One is the high-flying that flies at 20 kilometers (12 miles) altitude. A single specialized pilot wears a spacesuit and carries oxygen, and the plane’s broad wings let it fly through thinner air. That aircraft will collect large-scale observations from above the clouds.

“The instruments on the ER-2 will be the same as the ones flown on satellites,” McMurdie said. “But the airplane is closer to Earth and we can tell it where to go, so we can sample regions over and over again.”

The second aircraft is a research aircraft that will travel through the clouds, lower than commercial planes, for a bumpier flight that offers a close-up view of snow particles. Instruments on board will monitor exactly what types of snow is forming and falling from the clouds. The P-3 will also drop balloons over the ocean that carry a box of instruments to measure temperature, humidity and winds.

Snow is a challenge to detect from space because satellite models assume that the snow crystal is a simple geometrical shape, which isn鈥檛 realistic. 聽The most famous form of snow, snowflakes, are especially tricky to image from space. The lower aircraft includes instruments that can image individual flakes from two angles, to capture them head-on and in profile.

“Snow can be hundreds of different shapes, which is not easy to do mathematically,” McMurdie said. “The geometry alone is enough to put you through a tizzy. To assume your snow looks like round things is not what happens in the sky.”

The P-3, which was outfitted in November with the instruments it will carry during this campaign, will be based in Virginia. The high-flying ER-2 will be based in Georgia, outside the storm centers for easier takeoff and landing. The team hopes to observe storms around New York State including Long Island, where partners are collecting ground observations. The final flight routes will depend on the storm paths that nature delivers.

In the days leading up to a promising storm, the mission scientists will map out the flight paths. Depending on how far the storm is from Wallops Flight Facility, which determines the travel time to the storm, the aircraft can collect observations for four to six hours. The campaign also will use ground instruments and balloons to help complete the picture.

The observations will be used to study how snowstorms evolve and improve satellite observations of snowfall.

“I just love winter storms, they’ve always fascinated me. So it’s very exciting to find out how they work, and how snow gets distributed the way it does,” McMurdie said.

Other include NASA’s Goddard, Marshall and Langley centers; the National Oceanic and Atmospheric Administration and the National Weather Service, National Center for Atmospheric Research, Stony Brook University, which is conducting ground-based monitoring; North Carolina State University; University of Illinois at Urbana Champaign, which also will conduct ground-based observations; Pennsylvania State University; and the University of Oklahoma. The other 91探花participants will be atmospheric sciences postdoctoral researcher , graduate students and , and research scientist Stacy Brodzik.

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For more information, contact McMurdie at 206-685-9405 or lynnm@uw.edu. At NASA, contact Steve Cole at 202-358-0918 or stephen.e.cole@nasa.gov.

The 91探花 has won a national competition in which colleges vie to deliver the most accurate daily forecast for cities across the country. A 91探花student also developed a machine-learning model that for the first time delivered a more accurate forecast than any human competitor.

In results announced this week, the 91探花team placed first among 36 teams in the annual operated by the University of Oklahoma. , a research associate professor in atmospheric sciences, has led the 91探花team since its inception in 2011.

“We’ve been close many times, but this is our first win,” McMurdie said. “We were in first place for the last couple of weeks. It’s very exciting to bring the trophy to Seattle.”

, a doctoral student in atmospheric sciences, claimed the top individual prize. Several other 91探花contestants 鈥� including McMurdie and team captain 鈥� 聽placed in the top 10. Undergraduate placed third among juniors and seniors, and undergraduates and placed well and contributed to the team’s success.

During the challenge, participants make a forecast for the next day’s weather in a U.S. city. The contest moves to a new location every two weeks: This year’s included Omaha, Phoenix and Anchorage.

All students and current employees at higher education institutions in the U.S. and Canada can participate. At the UW, undergraduates can enroll in a one-credit pass/fail class, “,” that meets to discuss forecasting techniques.

“Our graduate students don’t do it for credit, they just do it for fun, but they often show up to the weekly meetings just to talk about the weather,” McMurdie said.

Zagrodnik, who recently earned a doctorate for his study of precipitation over coastal mountain ranges, has been the team’s student leader since joining the 91探花in 2014. As captain he helps with the team’s recruiting, logistics and coaching. He does it for fun, and enjoys sharing his forecasting knowledge.

“The real challenge in building a competitive team is you have new people every year and you have to quickly coach them up to learn the ropes. There’s always a scramble in September to get the newbies ready. But I enjoy it,” Zagrodnik said.

Teammates are allowed to discuss available forecasts and assess the conditions together, but they cannot directly influence each other’s forecasts. Each Monday through Thursday, contestants submit a forecast by 5 p.m. Seattle time for the next 24 hours of maximum and minimum temperatures, precipitation and sustained winds in the given contest city. Then they wait to see if the weather cooperates.

“They update the weather on the challenge site every hour, so you can watch the next day and see how you’re doing,” McMurdie said.

This year the 91探花team included more than 30 members. Of those, 14 submitted forecasts from September through March so they could be included in the team score. Team scores are a combination of the individual scores.

In true Seattle style, the 91探花team credits its win partly to custom software. Zagrodnik and others built a dashboard that brings together more than a dozen forecast models.

“There’s weather data everywhere on the internet,” Zagrodnik said. “We do a lot of work to pull that data into one location so our team has a dashboard they can look at to make a fast decision, without having to hunt all over.”

The dashboard also includes a computer model that uses machine learning to improve cities’ forecasts. The tool, developed by Weyn, compares historical forecasts for a given city with the actual weather to learn the models’ biases in different scenarios, and correct for them.

After the announcement of a new location, Weyn would train the tool with six or seven years of past forecasts and weather records for that city, and then make those results visible to the rest of the team.

Weyn’s machine-learning tool, , also entered in the “model” category along with many government models. Over two weeks in Pueblo, Colorado 鈥� the most unpredictable of this year’s cities 鈥� his model delivered the best forecasts.

It was the first time in the competition’s history that a computer beat all the human forecasters, and the organizers awarded Weyn a special category trophy.

The competition is not yet over. A playoff round, in March Madness bracket style, began April 1. The top 32 finishers from the regular season will sit out the first week.

Sixty-four contestants will then compete in two-day, head-to-head contests to forecast the weather in , South Carolina, with winners advancing to the next round. Weyn is the top seed for Region 1, and Zagrodnik is the top seed for Region 2. You can follow the 91探花team members’ progress through April 26.

Weyn, who will be the student lead for the team next year, said he’s most proud of the team’s first-place trophy.

“The overall team win is a big deal. The tournament is like a playoff season 鈥� random things happen,” Weyn said. “But the top standing for the entire regular season is quite an accomplishment.”

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For more information, or to join next year’s team, contact McMurdie at lynnm@uw.edu or 206-685-9405.

Two 91探花 atmospheric scientists are leaving for a weeks-long, firsthand study of some of the fiercest storms on the planet.

They will participate in , an international campaign in Argentina to monitor storms that occur east of the Andes near the slopes of another mountain range, the Sierra de C贸rdoba. The international team hopes to better understand how convective storm systems 鈥� the big systems that unleash torrential rains, hail and lightning 鈥� initiate and grow as they travel from the mountainous terrain eastward over the plains.

The campaign, led by the University of Illinois and primarily funded by the National Science Foundation, will run Nov. 1鈥揇ec. 15. The comes from the Spanish and Portuguese word for lightning.

“From looking at the satellites, scientists have noticed that this area of South America had the most extreme storms in the world, in terms of how tall they get, the frequency of lightning and the frequency of hail,” said , a 91探花research scientist in atmospheric sciences who is the UW’s principal investigator.

Rowe is part of the team using three , a radar dish loaded on the back of a pickup truck, to monitor precipitation and wind. The instrument bounces waves off drops of water and ice to measure the size of the particles and get a detailed look at wind speeds and direction.

In 2015, Rowe helped operate a single one of these instruments as part of the UW-led to observe storm systems over the Olympic Peninsula and test a new NASA precipitation satellite. This effort will also compare observations with that instrument, and an even newer National Oceanic and Atmospheric Administration weather satellite that includes lightning tracking, to see their sensors perform in situations 鈥� like hail and lightning that continues well into the night 鈥� that may be unique.

“The fundamental question is still related to the role of topography in modulating these storm processes,” Rowe said. “The forecast models are increasingly doing better with trying to understand how mountain ranges influence precipitation. But you have to study it in a lot of different weather regimes and a lot of different types of mountain ranges.”

, a 91探花research associate professor of atmospheric sciences, will coordinate the daily weather briefings during the 45-day campaign. Her team will include a 91探花graduate student, other U.S. and Argentine graduate students, and members of Argentina’s national weather service. The team already has started making practice forecasts as a warmup for the event. During the campaign, the team will issue a morning forecast of where storms are likely to hit, their intensity and longevity over the next 24 hours, and researchers will then position their equipment accordingly. Forecasts will be updated in late afternoon to aid in planning the next day’s operations.

The team will occupy a hotel in the tourist town of Villa Carlos Paz, using a hotel’s banquet room as a center of operations.

Safety is a priority, the researchers emphasize. The team wants to collect firsthand data but won’t send members into harm’s way. Researchers will use and social-media reports to verify severe weather conditions throughout the region.

“This kind of region, you know you’re going to get storms,” Rowe said. “They’re so frequent that you know you’re going to get data. But whether or not it’s ideal, that’s left up to the atmosphere and your luck.”

One focus will be watching the storms evolve over time. In parts of the U.S. like Colorado that experience similar storms, Rowe said, systems usually develop in the afternoons and generally only last a few hours; after the storms initiate near the Rocky Mountains, they travel eastwards over the Great Plains and often grow into large convective systems over an area too large to adequately observe from the ground.

“In Argentina, you have a situation where you can observe these systems well,” Rowe said. “You can get additional information well into the lifecycle that you couldn’t in the U.S.”

This terrain will let the team study long-lasting storms that are very intense, fueled by moisture from the Amazon Basin, and are easier to monitor over long periods.

“I am excited,” Rowe said. “Not that I don’t love West Coast rain, but this will be exciting 鈥� there’s never been this sort of data collected before in this region.”

The full set of includes ground-based weather radars, weather balloons, a ground-based lightning detection array, a research aircraft, ground-based weather stations and observation pods that can be quickly deployed from trucks. Different parts of the campaign are funded by NASA, NOAA, the U.S. Department of Energy and science agencies in Brazil and Argentina.

The local community stands to benefit from the effort. Central Argentina is the wine region, and vineyard owners cover their crops with nets to protect the vines from the frequent hail. Understanding the processes that create the hail and flooding events will help the local community forecast these events and better prepare for them. But it also promises to answer basic questions about storms.

“This is really fundamental science,” McMurdie said. “There are some really basic questions, and it’s a big opportunity to collect the data. We just hope the weather cooperates.”

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For more information, contact Rowe at akrowe@uw.edu, and (until Friday, Oct. 26) at 206-685-3767, and McMurdie at lynnm@uw.edu, or (until Tuesday, Oct. 23) at 206-685-9405. An open house will be held Oct. 31 in C贸rdoba, Argentina.

The project’s goal is to calibrate measurements made by the Global Precipitation Measurement satellite, which promises a next-generation view of rain and snow around the planet. The Olympic Peninsula is one of the few rainforests in the world located outside the tropics.

Scientists and 91探花graduate students have spent the fall placing storm-tracking equipment on the ground. The same topography and unique climate that made it a natural laboratory for the experiment have earned much of the area status as a national park. The team has carried equipment in by truck, by foot and even by mule.

Now the scientific storm-watchers hope Mother Nature will deliver some good material in the weeks to come.

“We’re not just checking the satellite’s observations, the way you might double-check a simple distance measurement,” said project manager , a 91探花research scientist in atmospheric sciences. “We’re checking the connection between what the satellite sees from space, what’s happening in the middle of the storm system, and what reaches the ground, which is what most people ultimately want to know. So we’re not just improving the satellite’s performance — we’re learning how storm systems work.”

The Olympic Peninsula gets an average of 16 inches of precipitation in November alone. The region is a natural laboratory to study precipitation, and one that will benefit from better precipitation forecasts, flood warnings and model estimates for how precipitation may change in the future.

The core , launched in early 2014, carries technology for the next generation of precipitation observations, including the new capability to detect snow and light rain. The next few weeks will test its space-based electronic eyes.

“We’ve designed an experiment where we have aircraft that are pretending to be the satellite,” said OLYMPEX principal investigator , a 91探花professor of atmospheric sciences.

Starting Thursday, Nov. 12, NASA’s will operate out of Joint Base Lewis McChord and fly at an altitude of 39,000 feet above storm clouds moving toward the Quinault and Chelhalis river basins. In mid-November it will be joined by NASA’s , which will fly farther above the clouds at 65,000 feet. Both planes will carry instruments similar to those used in space, to simulate satellite observations. A third aircraft, the University of North Dakota’s聽, will actually fly through the clouds to take direct measurements of the droplets and ice crystals.

Incoming storms from the Pacific Ocean hit the coast and quickly reach the Olympic Mountains. The bumps act like rocks in a river, forcing the clouds in the storm system up and around the rocks, which changes the character of the precipitation. Following the storms from the ocean to the mountains provides highly variable terrain that leads to fast-changing conditions for rainfall and snowfall 鈥� which are a challenge to measure from space because they change quickly and over short distances.

On the ground, a large weather radar by the mouth of the Quinault River and a Doppler-on-Wheels on the shore of Lake Quinault will be gazing up at the clouds, studying their internal structure and how this changes as the storms move from the ocean inland. Arrays of rain gauges and other instruments on the ground 鈥� including 聽鈥� will collect data on how much rainfall or snowfall reaches Earth’s surface. More ground instruments will image and count individual raindrops and snowflakes to get accurate small-scale pictures of heavy or light rain and snowfall.

“This stack of measurements lets us connect the dots between what we see from space, what happens in the clouds and what we measure on the ground,” said NASA scientist , who is leading the field campaign. Detailed ground measurements will help the team understand the fundamental processes within clouds that cause rain to fall as snow, sleet, rain or hail, driving downpour or light mist.

“All of these measurements are aimed at determining if the assumptions that we’re making about interpreting the satellite measurements are correct,” Houze said.

Houze, McMurdie, Petersen and 91探花graduate students will hold weather briefings each morning at the mission’s control room in the 91探花Atmospheric Sciences building. The large weather radars will be dismantled and flight missions will end by Dec. 21. Other equipment will continue to record data in the field until the team retrieves it in the spring.

The Global Precipitation Measurement is an international mission led by NASA and the Japan Aerospace Exploration Agency. Partners on the OLYMPEX mission are researchers at the University of Illinois, University of Utah, Texas A&M University, McGill University, Stony Brook University, Colorado State University, State University of New York, Environment Canada, as well as the U.S. Forest Service, the National Science Foundation, Quinault Indian Nation and the National Park Service.

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For more information, contact McMurdie at 206-685-9405 or mcmurdie@atmos.washington.edu. NASA will hold a and tour of the DC-8 aircraft Wednesday, Nov. 11 and can host media on flights throughout the week. Field sites will be operating most days; to arrange a visit, contact 91探花research scientist Angela Rowe at akrowe@uw.edu.

More photos are at and .

This article was adapted from a NASA .

This coming fall, the drops and flakes will be tracked as never before. Researchers are preparing for , a ground-based effort to calibrate and validate precipitation measurements made by the Global Precipitation Measurement () constellation of satellites. An international collaboration including the Japanese Aerospace Exploration Agency and NASA recently launched the core GPM satellite, equipped with new instruments that can measure a range of precipitation intensities, from light snowfall to heavy tropical rain.

“It’s exciting to have all these things come together, measuring storm systems in all these different ways,” said , a 91探花research scientist in atmospheric sciences.

, professor of atmospheric sciences, is the other 91探花lead on the project to validate the new satellites’ data.

The Olympic Peninsula is an ideal location to conduct a precipitation field campaign. It is situated within an active storm track and offers a unique venue to monitor storm systems and their evolution as they cross from the ocean to the coastal lowlands, and over complex terrain.

The high-tech storm watch will track weather from the air and on the ground. The most intense phase of the project is scheduled to start after the first week of November and continue for six weeks. Other sensors will stay on the ground throughout the winter until the spring thaw.

The ground campaign will include several dual-polarization weather radars to complement the one on Washington’s coast, as well as other special ground instruments measuring the type and amount of precipitation. Research aircraft carrying instruments similar to those on the GPM core satellite will fly over the ocean and over the weather radars and other ground sensors.

Instruments will measure the exact amount of precipitation in different places, determine the height where snow turns to rain in a storm system, and even measure the size of the drops 鈥� whether the precipitation falls as many small drops, or fewer big drops.

“The size of the drops tells us something about the processes that are creating the rain, and is an important quantity used in the precipitation algorithms for the satellite,” McMurdie said.

As part of the current gear-up phase, the team is asking the community for help. Residents from around the state, but especially from the Olympic Peninsula and Chehalis River basin to the south, are being sought to monitor precipitation. The citizen-science is helping with the recruitment. The network, which has operated in Washington since 2008, has more than 400 active volunteers, with 58 of those on the Olympic Peninsula.

The national volunteer rain-monitoring effort began in Colorado after a in 1997 was poorly forecasted by weather models and came as a surprise, killing five people and causing millions of dollars in damage.

Volunteers buy a $30 rain gauge, install it on their property, and then check it and report by computer each morning. Data from volunteers inside the study area will be entered into the NASA project database.

The data also will be used by 91探花doctoral student , who is installing rain gauges throughout the Chehalis River basin to understand how satellite precipitation estimates match up with actual river flows. The project is starting now and next year Gergel expects to deploy 30 to 50 rain gauges. The NASA-funded study, led by , research associate professor in civil and environmental engineering, will help to predict flooding in that region by building better models that use satellite data to forecast extreme precipitation events.

Other 91探花researchers who are involved with the NASA rain-monitoring campaign include in atmospheric sciences and in civil and environmental engineering, and 91探花graduate students in those two departments.

More on the NASA GPM satellites, which launched in February 2014:

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For more information, contact McMurdie at 206-685-9405 or mcmurdie@atmos.washington.edu. For information about the volunteer rain-gauge program contact Karin Bumbaco at 206-543-3145 or kbumbaco@uw.edu.