Photo feature: a lenticularly gorgeous sunset along the Front Range of Colorado

By Tom Yulsman | November 21, 2017 3:29 pm
lenticular

Lenticular clouds at sunset along Colorado’s Front Range mountains on Sunday, Nov. 19, 2017. (Photo: ©Tom Yulsman.)

The cloud formations in the photograph above, and those to follow, may look otherworldly, and maybe even a bit ominous. But they are perfectly benign (except when they herald an approaching storm), and are well known to meteorologists.

The scientific name for these cloud formations is “altocumulus standing lenticularus.’ But from here on out, I’ll just refer to them lenticular clouds.

If you’ve never seen lenticular clouds like these before, whether in pictures or in person, you might be tempted to believe that I’ve gone bananas with Photoshop. Not at all. I can assure you that what’s depicted in these images is what I saw this past weekend near my home in Niwot, Colorado, just east of the Front Range. (But in the interest of full disclosure, I have brightened the shadows a bit so that the landscape would look as it did to my own eyes.)

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The lenticular cloud formations as they appeared shortly after the Sun had set. Gold colors dominated, with orange, red and even green to follow as the sunset progressed. (Photo: ©Tom Yulsman)

Lenticular clouds like these often form when strong winds aloft are forced up and over high mountains. And mind you, ours are particularly high! In the photo at the top of this post, the mountain visible just to the left of my wife and way in the distance is Longs Peak, elevation 14,259 feet.

lenticular

Schematic of lenticular mountain waves. (Source: National Weather Service)

The air forced upward by the mountains is analogous to water flowing in a swift stream over a rock. Just downstream of the rock, the water then accelerates back downward – only to rise back up in one or more standing waves. These are akin to the ripples that occur when you throw a pebble in a pond.

This schematic illustrates the phenomenon. Moist air is forced upward as it passes over the mountain, and again in a standing wave downstream. As these parcels of air rise, they cool. And that cooling causes moisture to condense into clouds at the crests of the waves.

Often, these clouds can look like flying saucers. But here along the Front Range they are often layered and contorted in intricate, spectacular patterns — accentuated, of course, by the brilliant sunset glow. What’s up with that? Read More

A new weather satellite roars into orbit, promising faster and better forecasts of extreme weather like hurricanes

By Tom Yulsman | November 20, 2017 6:36 pm

The NOAA-20 satellite was to be the first of four, but the Trump Administration has sought to delay and massively cut the program

The new JPSS-1 satellite roared into orbit on Nov. 18, 2017.

The Joint Polar Satellite System-1 lifted off from Vandenberg Air Force Base, California, at 1:47 a.m. PST on Saturday, Nov. 18, 2017. When it successfully reached orbit, it was officially renamed NOAA-20. (Click the image to watch a video of the liftoff.) The satellite is designed to help meteorologists produce more timely and accurate U.S. weather forecasts three to seven days out. (Source: NOAA)

In the early morning hours of Saturday, Nov. 18th, a Delta  II rocket roared to life and propelled the newest U.S. weather satellite into orbit on a column of fire that lit up the nighttime sky of coastal California.

The NOAA-20 satellite is now circling the globe 14 times a day, orbiting from pole to pole at about 520 miles above the surface. It is equipped with five  instruments representing significant advancements from those on NOAA’s previous polar-orbiting satellites. NOAA-20 (called JPSS-1 prior to reaching orbit) is now on a shakedown cruise of about three months.

“The data these advanced instruments provide will improve weather forecasting, such as predicting a hurricane’s track, and aid in the recognition of climate patterns that can influence the weather, including El Nino and La Nina,” according to NOAA.

Data from NOAA-20 are also expected to help emergency managers respond to wildfires, volcanic eruptions, and other natural disasters. The satellite’s better views of damage and the extent of power outages should help communities recover.

“This year’s hurricane and fire seasons demonstrated just how critical NOAA’s Earth observing satellites are for forecasting extreme weather and hazardous events,” said Rear Admiral Timothy Gallaudet, Ph.D., acting NOAA administrator.

NOAA-20 won’t last forever – it is designed to operate for seven years. So it is supposed to be the first in a series of four satellites, with the next one scheduled for launch in 2022. But the future of the program has been called into question by a delay and massive budget cuts proposed by the Trump Administration.

Even Republicans in Congress are scratching their heads over this (more about that in a minute). That’s because they know that without advanced Earth observing satellites, Americans would suffer far greater damage, injuries and fatalities from natural disasters.

If you have any doubts about that yourself, consider the the Great Galveston Hurricane of 1900. Read More

The heat goes on, and on: This year will likely wind up as one of the three warmest on record

By Tom Yulsman | November 11, 2017 12:26 pm
North America, as seen by the GOES-16 weather satellite on Nov. 10, 2017. The sun had already set on about two-thirds of the country. (Source: CIRA/RAMMB/Colorado State University)

North America, as seen by the GOES-16 weather satellite on Nov. 10, 2017. The sun had already set on about three quarters of the continent. (Source: CIRA/RAMMB/Colorado State University)

With a month and a half to go until year’s end, it’s looking like 2017 will go down in the books as the warmest on record – that is, among years that received no temperature boost from El Niño.

Overall, 2017 is likely to be either the second or third warmest in records dating back to the 1800’s, according to a new report from the World Meteorological Organization.

Thanks to a boost from one of the strongest El Niño’s of all time, 2016 will almost certainly retain the record of warmest year, at least for now. And we’ll just have to wait to see whether the current year will beat out 2015 — which also got a boost from El Niño — as second warmest.

From WMO Secretary-General Petteri Taalas, quoted in a release: Read More

CATEGORIZED UNDER: Climate Change, ENSO, Global Warming

She’s back! As a giant blob of cold water arises from the depths, La Niña takes over the equatorial Pacific

By Tom Yulsman | November 10, 2017 3:12 pm

Will La Niña help bring a warmer or colder winter to your neck of the woods? And will it be wetter or drier? Read on.

blob

Cool sea surface temperatures in the equatorial Pacific are part of La Niña’s fingerprint. According to the latest advisory from NOAA’s Climate Prediction Center, La Niña conditions are now in place and stand a 65 percent to 75 percent chance of persisting into April. (Image: earth.nullschool.net)

Before I delve into the substance of this post, I should mention this: As regular readers may have noticed, I’ve been gone for awhile. That’s because my day job is directing the University of Colorado’s Center for Environmental Journalism, not ImaGeo — and sometimes there are just not enough hours in the day to keep up with everything. But now I’m very glad to be back. And so is…

La Niña!

Okay, I don’t know that she’s glad. But after arriving and departing quickly last winter, La Niña came back in October – albeit weakly. And it looks like she may hang around for awhile.

According to an advisory issued yesterday by NOAA’s Climate Prediction Center, she stands a very good chance of continuing through the Northern Hemisphere winter and into the spring.

Several conditions have to be met for the CPC to declare a La Niña. Among them: cooler than average temperatures in a part of the Pacific along the equator known as the Niño3.4 region. The graphic up top shows a large spear of cool surface water currently stretched across most of the equatorial Pacific, including Niño3.4.

Researchers also must feel confident that those cool conditions will persist for several seasons. The following animation suggests they will: Read More

CATEGORIZED UNDER: Climate, ENSO, Ocean, select, Top Posts, Weather

WATCH: Weather satellite video shows a 10-day dance of three powerful Atlantic hurricanes

By Tom Yulsman | September 29, 2017 12:46 pm
dance

This animation of GOES-16 weather satellite images shows three hurricanes in the Atlantic between Sept. 16 and 26, 2017: Jose, Maria and Lee. (Source: RAMMB/CIRA SLIDER)

It has been nine days since Hurricane Maria blasted ashore in Puerto Rico with 150 mile per hour winds, ravaging the entire island and leaving residents without electricity, food and water.

Today, thousands of containers of desperately needed supplies are sitting in ports and warehouses on the island, waiting to be distributed. But the hurricane left Puerto Rico’s supply chain devastated. So pharmacy and grocery store shelves remain mostly empty, raising fears that the death toll, now officially at 16, could soar unless something is done soon to get supplies moving out of the ports.

Maria’s misery was not limited to Puerto Rico, of course. Before coming ashore there, the ferocious storm flattened Guadalupe and Dominica in the Leeward Islands. Then it delivered a second Category-5 blow to the United States Virgin Islands – which had been pummeled by Hurricane Irma just 14 days earlier.

And these were not the only hurricanes to swirl through the Atlantic during September. The month has brought five to the basin: Lee, Maria, Jose, Katia and Irma. These storms have set a new record for “hurricane days” — the total number of days each Atlantic storm has managed to stay at hurricane strength — during a single calendar month. As of today, it stands at an astonishing 40 hurricane days.

September also brought a new record for accumulated cyclone energy, a measure integrating the number, strength, and duration of individual tropical cyclones, or of all the cyclones over a period of time. Before September has ended, the ACE total for the Atlantic has been the highest for any month on record.

SEE ALSO: Already, two significant records have tumbled during 2017’s fevered Atlantic hurricane season

The animation at the top of this story shows three of September’s hurricanes — Jose, Maria and Lee — prowling the Atlantic basin over a period of 10 days. It consists of imagery acquired by the GOES-16 weather satellite between September 16th and 26th.  Read More

Already, two significant records have tumbled during 2017’s fevered Atlantic hurricane season

By Tom Yulsman | September 27, 2017 10:55 am

With two months left, more records could fall before we’re all done

The GOES-16 weather satellite captured this image showing hurricanes Maria, to the left, and Lee, to the right, on the morning of Wednesday, Sept. 27, 2017. (Source: SLIDER by RAMMB/CIRA @ CSU)

The GOES-16 weather satellite captured this image showing hurricanes Maria, to the left, and Lee, to the right, on the morning of Wednesday, Sept. 27, 2017. (Source: SLIDER by RAMMB/CIRA @ CSU)

We’ve known for some weeks now that the 2017 Atlantic Hurricane season has been absolutely brutal.

And now, thanks to new calculations, we have some statistical insights into the raw, howling power of the storms that have caused so much death and destruction — most recently to Puerto Rico, now on the verge of a humanitarian crisis in the aftermath of Hurricane Maria.

On Tuesday, Colorado State university hurricane expert Phil Klotzbach reported that by two measures, September has already been the most active month for Atlantic tropical cyclones in records going back to 1893.

The first is accumulated cyclone energy. ACE is a measure that takes into account the number, strength, and duration of an individual tropical cyclone, or of all the cyclones over a period of time. And already for September, the ACE total for the Atlantic has been the highest of any month on record, according to Klotzbach. Read More

The weak underbelly of a giant Antarctic ice sheet just lost a berg more than four times the size of Manhattan

By Tom Yulsman | September 26, 2017 10:00 am
The Sentinel1 satellite captured this image of a 100-square-mile chunk of ice calving from Antarctica's Pine Island Glacier on September 23, 2017. (Source: Stef Lhermitte)

The Sentinel-1 satellite captured this image of a 100-square-mile chunk of ice calving from West Antarctica’s Pine Island Glacier on September 23, 2017. (Source: Stef Lhermitte)

We’ve now got yet another worrying sign that human-caused warming is causing the behemoth West Antarctic Ice Sheet to come unglued, threatening to raise sea level by 10 feet over time.

You can see that sign in the image above from the Sentinel-1 satellite.

The image shows a 103-square-mile tabular iceberg — equal in size to four and a half Manhattan islands — breaking off from the floating edge of the Pine Island Glacier in West Antarctica on September 23rd. It was posted to Twitter by Stef Lhermitte, a remote sensing expert at Delft University of Technology in the Netherlands.

The glacier is like a cork in a bottle, helping to restrain nearly 10 percent of the West Antarctic Ice Sheet from pouring out into the sea.

As the September 23rd calving event shows, the cork is eroding.

That was not the first time a chunk of the cork broke loose. In a very similar event in 2015, an iceberg twice as large calved from the glacial front. You can see that event in this time-lapse of Sentinel-1 images, as well as growth of the rift that led to the Sept 23rd calving: Read More

Giant blob of cold water rises from the depths of the Pacific, possibly heralding the arrival of La Niña this fall

By Tom Yulsman | September 23, 2017 12:21 pm
La Niña

This animation shows how temperatures at the surface and subsurface of the tropical Pacific ocean departed from average over five-day periods starting in early August 2017. The vertical axis shows the depth below the surface in meters. The cross-section is right along the equator. Note the blue blob indicative of relatively cool water rising from the depths and spreading eastward. (Source: NOAA ENSO Blog)

Here we go again?

Following a mild and short-lived La Niña episode in 2016/2017, the climatic phenomenon stands a 55 to 60 percent chance of developing once again this fall and winter. That’s the most recent forecast from the National Oceanic and Atmospheric Administration.

Based on observations of what’s happening in the Pacific Ocean, and modeling to predict what may be coming, NOAA’s Climate Prediction Center has issued a La Niña watch, indicating that conditions are favorable for its development.

La Niña can strongly shift weather patterns, bringing anomalously cool or warm, and wet or dry, conditions to large parts of the world. In the United States, La Niña tends to bring wetter than normal conditions to the Pacific Northwest and parts of the Midwest. Unfortunately for southern and central California, things tend to dry out. Read More

CATEGORIZED UNDER: Climate, ENSO, Ocean, select, Top Posts

We’re still on track to experience the second or third warmest year globally in records dating back to 1880

By Tom Yulsman | September 21, 2017 10:13 am
A global map from NASA of how Earth's surface temperatures last month departed from the 1951-1980 August average. (Source: NASA GISTEMP. Note: part of Antarctica is gray because data from some stations there were not yet available at the time of this analysis.)

A global map from NASA of how Earth’s surface temperatures last month departed from the 1951-1980 August average. (Source: NASA GISTEMP. Note: part of Antarctica is gray because data from some stations there were not yet available at the time of this analysis.)

Last month was among the very warmest on record, according to two new analyses – and the heat is very likely to continue.

With less than four months left to go in 2017,  the year will probably come in as second or third warmest on record.

Two agencies have produced very slightly different verdicts for this past August. NASA’s Goddard Institute for Space Studies has found that last month was the second warmest August globally in 137 years of modern record-keeping, surpassed only by August 2016. Global temperatures last year received an extra boost from a strong El Niño episode. Read More

After shrinking to a shocking record low at end of winter, Arctic sea ice staged a modest comeback this summer

By Tom Yulsman | September 20, 2017 12:03 pm

But despite claims to the contrary, one warmish summer in the Arctic does not repeal the long-term trend of human-caused warming

This visualization shows how the extent of Arctic sea ice has evolved through time. The animation begins when the ice reached its wintertime maximum extent on March 7, 2017, and it ends on September 13, 2017, when the ice shrank to its minimum extent for the year. (Source: NASA Scientific Visualization Studio/Helen-Nicole Kostis)

This visualization shows how the extent of Arctic sea ice has evolved through time. The animation begins when the ice reached its wintertime maximum extent on March 7, 2017, and it ends on September 13, 2017, when the ice shrank to its minimum extent for the year. (Source: NASA Scientific Visualization Studio/Helen-Nicole Kostis)

Arctic sea ice has staged something of a short-term turn-around this summer.

The underlying long-term warming of the region, caused by our emissions of heat-trapping greenhouse gases, has not abated. But relatively cool and cloudy weather in the high north during summer caused the sea ice to shrink less extensively than in some recent years.

When the ice reached its minimum extent for the year on September 13th, it turned out to be eighth lowest in the 38-year record of satellite observations, according to a preliminary analysis released yesterday by the National Snow and Ice Data Center.

This is especially noteworthy because the melt season began in March with sea ice at a record low for that time of year, thanks to unusually warm temperatures in winter that had caused sea ice to expand very sluggishly. But then the weather shifted.

Another factor was at work too: Relatively warm winter temperatures had enhanced snowfall onto the ice in parts of the Arctic. That slowed its summertime melt-out.

Even so, the minimum ice extent reached on September 13th was 610,000 square miles below the 1981 to 2010 median extent for that day – an area equivalent to about one sixth of the total area of the United States. Read More

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ImaGeo

ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.
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