Ocean temperatures and their connections to weather trends have been making news. Five 91探花 experts offer their perspectives on the current El Ni帽o 鈥� a climate pattern in the tropical Pacific Ocean that affects weather worldwide. 91探花researchers comment on the current El Ni帽o, its effect on weather in the Pacific Northwest, as well as on regional and global ocean temperature trends.

, a 91探花research scientist at the , comments on the developing El Ni帽o:

“This El Ni帽o has evolved in a really interesting way. Since spring, the dynamical models have very confidently predicted an El Ni帽o event. But while the key region of the tropical Pacific has warmed quickly, the typical atmospheric response has lagged. The atmosphere in the tropical Pacific is only now becoming more typical of an El Ni帽o event, although it is still not fully matching the ocean surface. That鈥檚 unusual, because the tropical ocean and atmosphere tend to evolve together.

“It will be interesting to see how this El Ni帽o continues to evolve over the next few months, which will help determine the extent of impacts on our upcoming winter weather. Remote impacts in places like Seattle tend to be stronger for stronger El Ni帽o events. While sea surface temperature has typically been the main measure, the impacts might very well depend more on the atmospheric response. So the evolution of the system over the next few months will be key to the eventual local impacts in places like Seattle.”

Dennis Hartmann, professor of atmospheric sciences at the UW, on El Ni帽o and its effects:

“The impact of El Ni帽o on the Pacific Northwest varies a lot from one event to the other, depending on the spatial structure and size of the sea surface temperature changes in the tropics, and on the state of the atmosphere between the tropics and the Pacific Northwest. For that reason, the predictions of Pacific Northwest impacts based upon El Ni帽o events that happened in the past are quite uncertain.

“In addition, the climate has warmed significantly in both the tropics and outside the tropics since some of the prior big El Ni帽o events, in the 1970s and 1980s. That may add an additional complication to making an accurate forecast of how this winter will be different because of the current El Ni帽o event.”

Nick Bond, a research scientist at CICOES and Washington鈥檚 state climatologist, on El Ni帽o and its effects on Washington鈥檚 weather:

“El Ni帽o conditions are present now in the tropical Pacific Ocean, and they are very likely to persist through the coming winter. The effects on Washington鈥檚 weather are expected to feature relatively warm, and perhaps drier, weather than usual after Jan. 1, and ultimately a lower-than-normal snowpack in our mountains at the end of winter. El Ni帽o’s impacts on the weather in Washington state tend to be more consistent in the middle to latter part of the winter.

“But this is not written in stone 鈥� there has been variability among past El Ni帽os in terms of effects on Washington鈥檚 winter weather.”

Jan Newton, senior principal oceanographer at the 91探花Applied Physics Laboratory and director of the UW-based , on what oceanographers are seeing in regional waters:

“Conditions off Washington鈥檚 outer coast have varied and are mainly influenced by changes in coastal upwelling and downwelling in the Pacific Ocean. Temperatures off the outer coast are now 4 degrees Fahrenheit (about 2 degrees Celsius) above normal, though variable.

“In Puget Sound, we鈥檙e starting to see surface water temperatures shift from cooler than normal, or normal, to consistently warmer than normal, but only by less than one degree Fahrenheit (half a degree Celsius). Given the large-scale warmth in the satellite-measured sea surface temperatures offshore, I do expect that we will continue to see warmer-than-normal sea temperatures in Puget Sound.聽 However, it鈥檚 hard to predict if these differences from the average will stay small or will increase. What happens next will depend on ocean conditions and local weather.”

LuAnne Thompson, 91探花professor of oceanography, on the :

“The recent acceleration of ocean warming in the Atlantic is unprecedented in the historical record, and has created an Atlantic-wide marine heat wave. The ability of the ocean to absorb and store vast amounts of heat makes these types of events last longer. I study marine heat waves with a focus on their evolution in time and space. However, with more long-lasting, basin-wide events, such as the one we are seeing now in the Atlantic Ocean, we will need to reevaluate our approach.

“At a particular location, a marine heat wave occurs when the sea surface temperature is above a threshold, defined by what is typical for that time of year, and lasts for at least five days. However, with the global warming projected over coming decades, these dangerous hot water events will no longer be localized and of finite duration 鈥� they will no longer fit the traditional definition of marine heat waves. Instead, these marine heat wave events will become more persistent and widespread, and eventually will cover entire ocean basins.”

For more information, contact Levine at aflevine@uw.edu, Hartmann at dhartm@uw.edu, Bond at nab3met@uw.edu, Newton at janewton@uw.edu and Thompson at luanne@uw.edu.

After many people in the Puget Sound region had dismissed any chance of snowfall in the lowlands this season, the region is now on track for not one, but two, and possibly even more snowstorms this winter.

, a 91探花 associate professor of atmospheric sciences who serves as , commented Thursday on the upcoming snowstorm 鈥� the second to hit the Puget Sound region this week.

The 91探花campus will suspend operations, including canceling classes, starting Friday midday, and updates are posted to the 91探花homepage and to the blog. Sign up for email and text alerts here.

It’s not a coincidence that we’re getting even more snow 鈥� the situation on the ground matters for the coming snowstorm, Bond said. Because the ground is already cold, that will chill the air enough that this storm will likely bring snow from the start, instead of rain followed by snow. Also, this cold spell means that snow will likely last on the ground longer.

“It is a very unusual situation we’re in, which is sustained cold weather,” Bond said. “Oftentimes, the atmospheric circulation patterns get into a state that’s favorable for snow, but because it’s a rare event, it just doesn’t hang around that long. Then we get back to more air coming off the Pacific Ocean that’s relatively mild, and a return to more normal temperatures.

“But in this particular case, we’ve just kind of gotten locked into a pattern where we’re going to continue to get colder air from the north, along with that special set of circumstances in which we can get the lift, the precipitation, and the snow to fall. It doesn’t happen very often 鈥� maybe every decade, or even two, that you have something like this. So it’s quite remarkable.”

Bond defers to the National Weather Service for exact predictions, and notes that the exact timing and location of the heaviest snowfall is hard to predict. But he expects it to be a more unusual event in the lowlands than at higher elevations.

“These patterns aren’t really huge snow producers for the mountains,” Bond said. “They don’t produce a great deal of total precipitation, so it’s not the most favorable for really piling up snow in the mountains. But they will get some, and our snow pack right now is a little below normal. We’re not panicking, but there is some concern about water supply next summer. So hopefully they’ll get some, too.”

Bond is a member of the , a collaborative research center between the 91探花and the National Oceanic and Atmospheric Administration.

The air that is hitting us is not the same mass of cold air that hit the Midwest a few weeks ago, but the two events are somewhat related, Bond said.

“If you were to track the wind patterns, and ridges of higher pressure and troughs of lower pressure, sometimes the overall pattern around the whole Northern Hemisphere will be more circular 鈥� very symmetric,” Bond said. “Other times, it has these big ridges and big troughs, so there are places with strong north winds and strong south winds. So we’ve been in one of those kind of wavier patterns.”

One common question in the media is whether the “polar vortex” might be destabilized, sending more Arctic air into the mid-latitudes under global warming. Bond said that with a short record and evidence on both sides, the jury “hasn’t even been called yet” to establish if that connection exists.

As for whether this cold snap disproves global warming, Bond said the answer is clearly no.

“This is weather, not global warming. 2018 was by most measures the fourth-warmest year on record. But these sort of cold-weather events will still happen.”

And the cold seems likely to stick around.

“Right now, it looks like it’s going to stay cold for an extended period 鈥� at least another week or so, maybe a little bit longer,” Bond said. “It won’t necessarily be bitterly cold, but below-normal temperatures. The crystal ball starts to get really fuzzy when you start to look longer than a week or so, and it doesn’t really imply anything for the spring.”

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For more information, contact Bond at nab3met@uw.edu

Early reports suggest that the winter of 2018/2019 will be a weak to moderate El Ni帽o year. For the Pacific Northwest, that probably means less snow in the mountains than average, especially late in the season.

“El Ni帽o is when the tropical Pacific is warmer than normal, right in a thin strip along the equator, and what happens as a result is there’s a shift in these large clusters of thunderstorms, and that has a ripple effect on the atmospheric circulation over much of the globe 鈥� including in our neck of the woods,” explained , a 91探花 associate professor of atmospheric sciences who studies links between the ocean and atmosphere.

El Ni帽o winters tend to be warmer than normal, especially after January 1, said Bond, who also serves as the ..

For skiers, “El Ni帽os aren’t all bad,” Bond added. “In particular, early on in the winter there can be some good conditions 鈥� some healthy snows. One thing we do see is a tendency for less snow pack than usual at the end of an El Ni帽o winter. That means at certain elevations, maybe a little bit more rain versus snow.”

Meteorologists can predict an El Ni帽o or La Ni帽a year with some skill six months or even farther out, he said.

91探花 researchers are tracking what the season will deliver to the Pacific Northwest region.

For Washington, El Ni帽o typically brings warm, and often dry, winter weather. That may seem surprising, since the state just experienced a very wet December, according to the latest from the UW-based state climatologist’s office. Many places broke previous records for the month. But that precipitation does not seem to be linked to El Ni帽o.

“We were very fortunate, from a water-supply point of view, to get all that lowland rain and mountain snow when we did, because that’s not always the case during El Ni帽o,” said , Washington’s state climatologist and a researcher with the UW-based .

“And looking ahead, at least in the short term, it looks like there’s not going to be a lot of precipitation.”

The West Coast effects of El Ni帽o tend to peak in January and February and continue to be felt through March. But the Godzilla El Ni帽o in the tropical Pacific doesn’t necessarily mean we need to brace for monster-sized effects in this region.

“There’s not a strict relationship between the magnitude of the El Ni帽o and the magnitude of the response at the higher latitudes,” Bond said. “Sometimes more moderate El Ni帽os seem to have a really big response, and other times the strong ones have a more moderate response. It’s not a one-to-one relationship.”

So far, this El Ni帽o is shaping up to be a textbook event, said , a 91探花professor of atmospheric sciences who has covered the topic on his .

“It’s been following the typical route for a strong El Ni帽o,” Mass said. “Typically, even a strong El Ni帽o doesn’t have a lot of implications for this region in the early winter, but after the first of the year the teleconnections develop and the jet stream splits to bring rainstorms to California and Alaska, with Washington right in the middle,” he said.

“This El Ni帽o is following the typical game plan, particularly the increasing effects after the new year.”

Observations show this El Ni帽o is already weakening in the tropics, Mass said, and models suggest a neutral situation by the middle of summer, and either neutral or the opposing La Ni帽a phase by next winter.

Along the West Coast, El Ni帽o conditions tend to bring higher sea level and bigger winter waves, which together can create more flooding and storm damage along the coast. They also can shift the direction of storm waves to come from the southwest, rather than from the west, which has been shown in past years to alter the shape of beaches in Oregon and California.

How these various factors influence Washington state, though, is less clear, said , a coastal hazards specialist in Port Angeles with the UW-based . Miller discussed the coastal effects of El Ni帽o in a last fall. He will be checking tide gauges to see if average sea levels for the year are unusually high, and visiting beaches to see how they fare this season.

“One of the things I’m interested in doing this winter is better documenting what an El Ni帽o winter means for Washington’s coast, in particular the north coast and the Strait of Juan de Fuca,” Miller said.

In the water, El Ni帽o leaves its mark by both water and air, said , an oceanographer at the 91探花Applied Physics Laboratory who tracks regional ocean conditions.

“During an El Ni帽o year we often have warmer and saltier than normal ocean conditions,” Newton said. “And it’s coming from both the effect of the ocean, which would have those warmer waters, and the effects on our weather, which would be warmer air temperatures and less precipitation.”

El Ni帽o’s effects on the ocean will largely replace the phenomenon known as “,” the unusually warm patch in the northern Pacific that influenced coastal weather and marine ecosystems in 2014 and 2015.

That pattern 鈥� which included ocean temperatures of up to 7 degrees Fahrenheit warmer than usual 鈥� continues to be a subject of scientific study. A at the 91探花Jan. 20 and 21 will review the unusual pattern of the blob, its effects, whether this event could have been forecast, and also consider how any remnants may be interacting with El Ni帽o.

Although the warm-water blob is now mostly history, climate models project that the coastal winds will be more from the south than usual, resulting in a strip of relatively warm water along the West Coast this spring, Bond said. This phenomenon is related to yet another climate cycle known as the .

“All the models are showing that to be the case, but to varying extent. It looks like it will be warm enough along the coast to have some significant effects,” Bond said. “People are keeping an eye on that, because the ocean has [already] been warm for a couple of years. If that continues, it’s going to have implications for the marine ecosystem.”

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For more information, contact Bond at 206-526-6459 or nab3met@uw.edu, Mass at 206-685-0910 or cliff@atmos.washington.edu, Miller at 360-417-6460 or immiller@uw.edu, and Newton at 206-543-9152 or newton@apl.washington.edu.

Reporters interested in attending the “” workshop Jan. 20-21 should contact Newton at newton@apl.washington.edu.

The 91探花 and Mt. Baker Ski Area are collaborating this month to present “.” The free 20-minute talks by 91探花faculty members will take place three consecutive Saturdays at 3:30 p.m. in the ski area’s White Salmon Lodge.

The first presentation on Jan. 9, will be given by , 91探花professor of atmospheric sciences, who will talk about “The Future of Ice 鈥� Far and Near.” Her talk is a fitting kickoff for the series, which is an outreach effort by the UW’s interdisciplinary initiative.

Next will be , professor of aquatic and fishery sciences, who will speak Jan. 16 on “Climate and the Future of Salmon in the Pacific Northwest.” Schindler’s research looks at how factors such as climate change and urbanization affect salmon populations in Alaska and the Northwest.

The final presentation, on Jan. 23, will be by , researcher with the UW’s Joint Institute for the Study of the Atmosphere and Ocean and Washington’s state climatologist, who will speak on “El Ni帽o, the Blob and Climate Change: What it Means for Our Neck of the Woods.”

The series gets its title from the recent agreement to try and , signed in December at a meeting of world leaders in Paris.

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For more information, contact series coordinator and 91探花Future of Ice postdoctoral researcher Sarah Myhre at semyhre@uw.edu.

A long-lived patch of warm water off the West Coast, about 1 to 4 degrees Celsius (2 to 7 degrees Fahrenheit) above normal, is part of [a larger pattern driven by the tropical Pacific] that’s wreaking much of this mayhem, according to two 91探花 papers to appear in Geophysical Research Letters, a journal of the American Geophysical Union.

“In the fall of 2013 and early 2014 we started to notice a big, almost circular mass of water that just didn’t cool off as much as it usually did, so by spring of 2014 it was warmer than we had ever seen it for that time of year,” said , a climate scientist at the UW-based , a joint research center of the 91探花and the U.S. National Oceanic and Atmospheric Administration.

Bond coined the term “” last June in his monthly newsletter as Washington’s state climatologist. He said the huge patch of water 鈥� 1,000 miles in each direction and 300 feet deep 鈥� had contributed to Washington’s mild 2014 winter and might signal a warmer summer.

Ten months later, the blob is still off our shores, now squished up against the coast and extending about 1,000 miles offshore from Mexico up through Alaska, with water about 2 degrees Celsius (3.6 degrees Fahrenheit) warmer than normal. Bond says all the models point to it continuing through the end of this year.

The new explores the blob’s origins. It finds that it relates to a persistent high-pressure ridge that caused a calmer ocean during the past two winters, so less heat was lost to cold air above. The warmer temperatures we see now aren’t due to more heating, but less winter cooling.

Co-authors on the paper are at NOAA in Seattle and a 91探花affiliate professor of oceanography, at NOAA in Santa Cruz and at Canada’s Department of Fisheries and Oceans. The study was funded by NOAA.

The authors look at how the blob is affecting West Coast marine life. They find fish sightings in unusual places, supporting recent reports that West Coast and the by warm, less nutrient-rich Pacific Ocean water.

The blob’s influence also extends inland [to affect West Coast weather]. As air passes over warmer water and reaches the coast it brings more heat and less snow, which the paper shows helped cause current drought conditions in California, Oregon and Washington. [As air passes over warmer water it picks up heat, resulting in a tendency for warmer temperatures and reduced mountain snow packs, which may be exacerbating current drought conditions along the West Coast.]

The blob is just one element of a broader pattern in the Pacific Ocean whose influence reaches much further 鈥� possibly to include two bone-chilling winters in the Eastern U.S.

A study in the same journal by , a 91探花professor of atmospheric sciences, looks at the Pacific Ocean’s relationship to the cold 2013-14 winter in the central and eastern United States.

Despite all the talk about the “polar vortex,” Hartmann argues we need to look south to understand why so much cold air went shooting down into Chicago and Boston.

His shows a decadal-scale pattern in the tropical Pacific Ocean linked with changes in the North Pacific, called the North Pacific mode, that sent atmospheric waves snaking along the globe to bring warm and dry air to the West Coast and very cold, wet air to the central and eastern states.

“Lately this mode seems to have emerged as second to the El Ni帽o Southern Oscillation in terms of driving the long-term variability, especially over North America,” Hartmann said. The research was funded by the National Science Foundation.

In a last month, Hartmann focused on the more recent winter of 2014-15 and argues that, once again, the root cause was surface temperatures in the tropical Pacific.

That pattern, which also causes the blob, seems to have become stronger since about 1980 and lately has elbowed out the Pacific Decadal Oscillation to become second only to El Ni帽o in its influence on global weather patterns.

“It’s an interesting question if that’s just natural variability happening or if there’s something changing about how the Pacific Ocean decadal variability behaves,” Hartmann said. “I don鈥檛 think we know the answer. Maybe it will go away quickly and we won’t talk about it anymore, but if it persists for a third year, then we’ll know something really unusual is going on.”

Bond says that although the blob does not seem to be caused by climate change, it has many of the same effects for West Coast weather.

“This is a taste of what the ocean will be like in future decades,” Bond said. “It wasn’t caused by global warming, but it’s producing conditions that we think are going to be more common with global warming.”

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For more information, contact Bond at nab3met@uw.edu or 206-526-6459 and Hartmann at dhartm@uw.edu or 206-543-7460.

[Note: The 2nd and 9th paragraphs were updated for clarity on April 22, 2015.]

‘Hurricane hunter’ measures polar vortex

A long-planned mission researchers had feared could be finally left in late October. , a research meteorologist at the Joint Institute for the Study of the Atmosphere and Ocean, returned from 2 1/2 weeks in Alaska as part of a trip to measure how less ice and more open water in the Arctic Ocean might influence storm paths.

The partnership between the 91探花and the National Oceanic and Atmospheric Administration used NOAA’s “hurricane hunter” aircraft to and see how heat radiating off the surface could destabilize the polar vortex, a huge weather feature that can affect storms throughout the Northern Hemisphere.

“When the polar vortex is strong, it’s very stable,” Bond said. “It’s like a Frisbee spinning fast 鈥� it’s stable and the cold air that develops in the Arctic is kind of bottled up.”

When the polar vortex is weaker, however, wobbles can send cold air shooting south. That’s when places like New York City, Washington, D.C., Northern Europe and Eastern Asia get hit with snowstorms and wintry weather.

Some scientists have suggested that an ice-free Arctic Ocean could destabilize the polar vortex. The mission collected data to help test this controversial theory, Bond said.

The measurements meant flying just 200 feet above the surface, and it often felt closer than that, Bond said. The specialized aircraft was equipped with more instruments than most weather stations to collect detailed measurements of heat and air turbulence.

In coming months, Bond and his colleagues will analyze the data and compare the observations with output from weather forecasting and climate models. They hope to understand whether the extra heat from the open water is enough to destabilize the polar vortex. Also of interest is how well weather-forecasting and ice models can predict conditions in the Chuchki Sea northwest of Alaska, an area now being explored for its oil.

The 16-day federal shutdown delayed the mission, but unseasonably warm weather meant the team was taking measurements at the right time to capture the fall freeze-up, Bond said.

“We were just fortunate, and it actually worked out pretty well,” he said.

Measuring summer glacier melt

Also this month, 91探花researchers helped the National Aeronautics and Space Administration create laser maps of melting Greenland glaciers. , a geophysicist with the 91探花Applied Physics Laboratory, helped design flight paths for the 16-day that ended Saturday (Nov. 16).

Scientists hope to better understand glaciers, the wild card in terms of climate change and rising sea levels. A NASA research aircraft used lasers to make an elevation-change map for important parts of the Greenland ice sheet.

Smith will compare the new data with similar measurements taken last spring to calculate how much the surface melted during the summer. This first-ever fall measurement will provide a baseline estimate of summer melt, in preparation for year-round laser monitoring of glaciers set to begin in 2016.

“Jakobshavn Glacier is the most exciting glacier in Greenland right now because it’s losing tremendous amounts of mass into the ocean,” Smith said. Flight paths included measurements right at the foot of the glacier, where ice is lost both to melting and to icebergs calving, and higher up on the ice sheet in colder conditions.

The government shutdown delayed the flight and some snow had already accumulated on the glacier. Another consequence was the temperatures 鈥� flights conducted by NASA scientists were very cold, Smith said.

UW鈥揅oast Guard monitoring flights

Also under way this month is the last installment this year in a series of flights in which 91探花Applied Physics Laboratory on flights out of Kodiak, Alaska to drop oceanographic probes into cracks in the sea ice and deploys buoys in tough-to-reach Northern waters.

, an oceanographer at the Applied Physics Lab, leaves Tuesday (Nov. 19) for his first such flight in three months. This will be the latest in the year that the 40-year veteran of Arctic research has ever been out on the ice.

“With the limited daylight, finding open water for our sensor drops will be challenging,” Morison said.

The ocean current and temperature observations help 91探花researchers, the National Snow and Ice Data Center and others to monitor and understand changing Arctic conditions.

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For more information, contact Bond at 206-526-6459 or nab3met@uw.edu; Smith at 206-616-9176 or bsmith@apl.washington.edu and Morison at 206-543-1394 or morison@apl.washington.edu.

Pictures of the NOAA trip:

NOAA news release: “”听听听听听听听听听听听听听听听听听听听听听听听听听听听

NASA news release: ““

“Being able to predict future phytoplankton blooms, ocean temperatures and low-oxygen events could help fisheries managers,” said , a research scientist at the UW-based .

“This is an experiment to produce the first seasonal prediction system for the ocean ecosystem. We are excited about the initial results, but there is more to learn and explore about this tool 鈥� not only in terms of the science, but also in terms of its application,” she said.

In January, when the prototype was launched, it predicted unusually low oxygen this summer off the Olympic coast. People scoffed. But when an unusual low-oxygen patch developed off the Washington coast in July, some skeptics began to take the tool more seriously. The new tool predicts that low-oxygen trend will continue, and worsen, in coming months.

“We’re taking the global climate model simulations and applying them to our coastal waters,” said , a 91探花research meteorologist. “What’s cutting edge is how the tool connects the ocean chemistry and biology.”

Bond’s research typically involves predicting ocean conditions decades in advance. But as Washington’s state climatologist he distributes quarterly forecasts of the weather. With this project he decided to combine the two, taking a seasonal approach to marine forecasts.

The National Oceanographic and Atmospheric Administration funded the project to create the tool and publish the two initial forecasts.

“Simply knowing if things are likely to get better, or worse, or stay the same, would be really useful,” said collaborator , a biologist at NOAA’s Northwest Fisheries Science Center.

Early warning of negative trends, for example, could help to set quotas.

“Once you overharvest, a lot of regulations kick in,” Levin said. “By avoiding overfishing you don’t get penalized, you keep the stock healthier and you’re able to maintain fishing at a sustainable level.”

The is named the JISAO Seasonal Coastal Ocean Prediction of the Ecosystem, which the scientist dubbed J-SCOPE. It’s still in its testing stage. It remains to be seen whether the low-oxygen prediction was just beginner’s luck or is proof the tool can predict where strong phytoplankton blooms will end up causing low-oxygen conditions, Siedlecki said.

The tool uses global climate models that can predict elements of the weather up to nine months in advance. It feeds those results into a developed by the 91探花Coastal Modeling Group that simulates the intricate subsea canyons, shelf breaks and river plumes of the Pacific Northwest coastline. Siedlecki added a new that calculates where currents and chemistry promote the growth of marine plants, or phytoplankton, and where those plants will decompose and, in turn, affect oxygen levels and other properties of the ocean water.

The end product is a for Washington and Oregon sea surface temperatures, oxygen at various depths, acidity, and chlorophyll, a measure of the marine plants that feed most fish. Coming this fall are sardine habitat maps. Eventually researchers would like to publish forecasts specific to other fish, such as tuna and salmon.

The researchers fine-tuned their model by comparing results for past seasons with actual measurements collected by the , or NANOOS. The UW-based association is hosting the forecasts as a forward-looking complement to its growing archive of Pacific Northwest ocean observations.

Siedlecki’s analyses suggest the new tool is able to predict elements of the ocean ecosystem up to six months in advance.

Researchers will present the project this year to the , the regulatory body for West Coast fisheries, and will work with NANOOS to reach tribal, state, and local fisheries managers.

If the forecasts prove reliable, they could eventually be part of a new management approach that requires knowing and predicting how different parts of the ocean ecosystem interact.

“The climate predictions have gotten to the point where they have six-month predictability globally, and the physics of the regional model and observational network are at the point where we’re able to do this project,” Siedlecki said.

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For more information, contact Siedlecki at 206-616-7328 or siedlesa@uw.edu and Bond at 206-526-6459 or nab3met@uw.edu.

And if you don’t sleep well in hot weather, this might be a good time to buy a fan, since records show that on average heat waves tend to strike around the last week of July.

91探花 research shows that the region west of the Cascades saw only three nighttime heat waves between 1901 and 1980, but that number quadrupled to 12 nighttime heat waves in the three decades after 1980, according to a published in the July issue of the .

Nighttime heat waves are when the daily low is in the top 1 percent of the temperatures on record 鈥� in Seattle above around 61.5 F 鈥� for at least three nights in a row.

“In general, minimum daily temperatures have been warming faster than maximum temperatures, so we’re not surprised to see a trend in the minimum events,” said corresponding author Karin Bumbaco, a research scientist at the . “Still, we were surprised to see this significant increase in the frequency of nighttime heat waves.”

She and co-author Nicholas Bond, both with the , began the investigation after fielding questions during the , which broke temperature records and led to a local run on fans and air conditioners. People wanted to know how that event compared with others in the history books.

The two ran the numbers with the help of Oregon State University’s at the Oregon Climate Service. They studied temperature readings west of the Cascade Mountains in Washington and Oregon from 1901 to 2009, looking for instances where the daytime high or nighttime low temperature hit the top 1 percent of readings for at least three consecutive days.

The 2009 scorcher set records in daytime temperature, but it was the string of warm nights that stood out, Bumbaco said. By their definition it was a three-day daytime heat wave in the Pacific Northwest 鈥� but included eight consecutive hot nights, the longest seen in the observational record.

“It was hard to cool down at night, there wasn’t much relief at all,” Bumbaco said.

Researchers also found a clue to suggest why we’re seeing more hot nights. It’s well known that Pacific Northwest heat waves occur when breeze off the ocean is replaced with air flow from the east, which warms up as it flows down the western slope of the Cascade Mountains.

But they found another trait for nighttime heat waves. The records show that nighttime heat waves happen during high humidity, where water vapor in the air serves as a blanket to trap heat.

“Forecasters already do a good job at predicting when heat is coming into the region, but this might help differentiate between hot days versus hot nights,” Bumbaco said.

Predictions are that climate change will bring longer, more extreme and more frequent heat waves during the day and night. The paper found no significant trend in the historical record of daytime events.

Though it was not part of the study, the recent late-June 2013 hot spell included just two extremely hot days, but readings at SeaTac Airport showed it qualified as yet another nighttime heat wave, Bumbaco said.

The study also includes a preliminary look at health effects from heat waves, which in the U.S. account for about 1,500 deaths each year. It found a 50 percent increase in the number of regional hospitalizations coded as being related to heat on dates the authors identified as heat waves. The most heat-related hospital admissions were during the 2009 heat wave and during a 2006 event that had the warmest nights on record. This corroborates other studies suggesting that nighttime heat has the most impact on human health.

Northwesterners are unlikely to draw sympathy from people across the country who are weathering triple-digit summer temperatures. But there is reason for concern. Because the region has mild temperatures people are not acclimatized to extreme heat and, perhaps most importantly, most people do not own air conditioners in their homes.

The research was funded by the State of Washington through the state climatologist’s office.

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For more information, contact Bumbaco at kbumbaco@uw.edu or 206-543-3145.

• When it rains or snows during Seahawks home games, the team’s record during the past decade is 17-4, a winning percentage of 0.81. The average point differential is almost 12.
• Without precipitation, the Seahawks record in home games is 42-25, a winning percentage of 0.63. The average point differential is about 5.

Bond checked the weather during home games going back to 2002 and compared that with the wins and losses during the regular football season.

“The home team thrives in bad weather,” Bond said.

Not that Seattle has all that much bad weather during home games. It appears there was precipitation at or in the immediate vicinity of the stadium during 21 of 88 home games, about a quarter of the time. Some years, for instance 2004 and 2009, weather for all the home games was dry. When there was precipitation it was mostly rain, but for two games there was snow.

Bond is deputy director of the UW-based and also serves as the .

Why’d he check this out?

“My son and I were watching the Seahawks rout of the 49ers Dec. 23 when the announcer mentioned that it was raining and in the low 40s but that Seattle was used to that. It got the two of us talking about whether inclement weather provides the Seahawks with an advantage, and so I decided to look into it,” Bond said.

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For more information:
Bond,206-526-6459, nab3met@uw.edu