Sailing for Science

In a study recently published in Geophysical Research Letters, scientists from the University of Washington and NOAA’s Pacific Marine Environmental Laboratory use remotely-piloted sailboats to gather data on cold air pools, or pockets of cooler air that form below tropical storm clouds.

“Atmospheric cold pools are cold air masses that flow outward beneath intense thunderstorms and alter the surrounding environment,” said lead author Samantha Wills, a postdoctoral researcher at the Cooperative Institute for Climate, Ocean and Ecosystem Studies. “They are a key source of variability in surface temperature, wind and moisture over the ocean.”

High Seas Research

The paper is one of the first tropical Pacific studies to rely on data from Saildrones, wind-propelled sailing drones with a tall, hard wing and solar-powered scientific instruments. Co-authors on the NOAA-funded study are Dongxiao Zhang at CICOES and Meghan Cronin at NOAA.

Atmospheric cold pools produce dramatic changes in air temperature and wind speed near the surface of the tropical ocean. The pockets of cooler air form when rain evaporates below thunderstorm clouds. These relatively dense air masses, ranging between 6 to 125 miles (10 to 200 kilometers) across, lead to downdrafts that, upon hitting the ocean surface, produce temperature fronts and strong winds that affect their surroundings. How this affects the larger atmospheric circulation is unclear.

“Results from previous studies suggest that cold pools are important for triggering and organizing storm activity over tropical ocean regions,” Wills said.

To understand the possible role of cold pools in larger tropical climate cycles, scientists need detailed measurements of these events, but it is hard to witness an event as it happens. The new study used uncrewed surface vehicles, or USVs, to observe the phenomena.

Over three multi-month missions between 2017 and 2019, 10 USVs covered over 85,000 miles (137,000 kilometers) and made measurements of more than 300 cold pool events, defined as temperature drops of at least 1.5 degrees Celsius in 10 minutes. In one case, a fleet of four vehicles separated by several miles captured the minute-by-minute evolution of an event and revealed how the cold pool propagated across the region.

“This technology is exciting as it allows us to collect observations over hard-to-reach, under-sampled ocean regions for extended periods of time,” Wills said.

The paper includes observations of air temperature, wind speed, humidity, air pressure, sea surface temperature and ocean salinity during cold pool events. The authors use the data to better describe these phenomena, including how much and how quickly air temperatures drops, how long it takes the wind to reach peak speeds, and how sea surface temperature changes nearby. Results can be used to evaluate mathematical models of tropical convection and explore more questions, like how the gusts created by the temperature difference affect the transfer of heat between the air and ocean.

Humans Have Always Dealt With Climate Change

Photo Credit:

In a paper published in Proceedings of the National Academy of Sciences (PNAS) this week Dr. Kaboth-Bahr and an international group of multidisciplinary collaborators identified ancient El Niño-like weather patterns as the drivers of major climate changes in Africa. This allowed the group to re-evaluate the existing thought regarding climate impacts on human evolution.

Dr. Kaboth-Bahr and her colleagues integrated 11 climate archives from all across Africa covering the past 620 thousand years to generate a comprehensive picture of when and where wet or dry conditions prevailed over the continent. “We were surprised to find a distinct climatic east-west ‘seesaw’ a lot like the pattern produced by the weather phenomena of El Niño, that today profoundly influences precipitation distribution in Africa,” explains Dr. Kaboth-Bahr, who led the study.

Wet and dry regions shifted between the east and west of the African continent on timescales of approximately 100,000 years, with each of the climatic shifts being accompanied by major turnovers in flora (plant-life) and mammal fauna (animal-life).

Photo Credit: Fine Art America

“This alternation between dry and wet periods appeared to have governed the dispersion and evolution of vegetation as well as mammals in eastern and western Africa,” explains Dr. Kaboth-Bahr. “The resultant environmental patchwork was likely to have been a critical component of human evolution and early demography as well.”

The scientists’ work suggests that a seesaw-like pattern of rainfall alternating between eastern and western Africa probably had the effect of creating critically important ecotonal regions — the buffer zones between different ecological zones, such grassland and forest.

Ecotonesprovided diverse, resource-rich and stable environmental settings thought to have been important to early modern humans,” adds Dr. Kaboth-Bahr. “They certainly seem to have been important to other faunal communities.”

Image Credit: ZMEScience

“Re-evaluating these patterns of stasis, change and extinction through a new climatic framework will yield new insights into the deep human past,” says Dr. Kaboth Bahr. “This does not mean that people were helpless in the face of climatic changes, but shifting habitat availability would certainly have impacted patterns of demography, and ultimately the genetic exchanges that underpin human evolution.”

Or as I like to say…”Weather is everything”.

That’s Not Rain, It’s

“Brood X” cicadas hatching in such massive numbers the swarms are being picked up by weather RADAR.

Photo Credit:

Just this past weekend the National Weather Service Baltimore-Washington Office paid special attention to huge areas of “Biological” returns showing on the Sterling, VA RADAR.

Credit: National Weather Service Baltimore-Washington

2020, We Remember You Well

Having the quality and quantity of weather data now at our disposal is awesome for forecasting. Sometimes though, it’s just plain cool.

The European Organisation for the Exploitation of Meteorological Satellites, aka Eumetsat, combined its own satellite images with contributions from the China Meteorological Administration, the Japan Meteorological Agency and the National Oceanic and Atmospheric Administration to create phenomenal video.

Video Production Credit: Eumetsat

The Hottest Place on Earth

two green cactus plants at daytime
Photo by Yigithan Bal on

Air temperature is measured about 6 feet above the ground in a ventilated shelter that is painted white. This method allows the temperature “in the shade” of air passing through the shelter.

Using this process Death Valley, CA is known as the hottest place on Earth due to the Furnace Creek, CA temperature of 134.1°F (56.7°C) recorded on July 10, 1913.

That’s air temperature, ground surface temperatures are a different beast.

Over the past 20 years NASA has been using satellites equipped with a Moderate Resolution Imaging Spectroradiometer (MODIS) to measure the infrared heat emitted by surfaces like dirt, rocks, etc. to see how hot they get. You’ve certainly experienced touching really hot surfaces during a sunny day (think metal car door). Radiation from the sun mercilessly heats these objects on sunny days.

Using the MODIS data there are two places that have leaped to the top of the surface heat heap; the Lut Desert in Iran, and the Sonoran Desert along the U.S.-Mexico border where temperatures have reached 177.4°F (80.8°C).

The Lut Desert has a larger area with these scorching surface temperatures and is now considered to be the “Hottest Place on Earth”.

Lut Desert, Iran

Lut Desert, Iran

In this Month’s Bulletin of the American Meteorological Society researcher Yunxia Zhao of the University of California, Irvine reveals other mind-bending facts about temperatures here on planet Earth:

The biggest temperature swing in a single day : 147.3°F (81.8°C), from –10.7°F (–23.7°C) to 136.6°F (58.1°C) on July 20, 2006 in China’s Qaidam Basin, a crescent-shaped depression hemmed in by mountains on the Tibetan Plateau.

Qaidam Basin, China

And the coldest place? No shocker here; with a satellite reading of -167.6°F (-110.9°) recorded in 2016 Antarctica reigns supreme.

Valley Fever

Arizona dust devil. Photo credit NASA/Tom Gill

Dust in the air in Arizona is not only irritating, it can severely damage your health. Valley Fever is caused by the the Coccidioides fungus which grows in dirt and fields and can cause fever, rash and coughing.

George Mason University’s Daniel Tong, one of the first scientists to discover the link between dust storms and Valley fever is leading a NASA-funded team to track the airborne spread of Valley fever across the United States for the first time.

There are about 15 thousand cases of Valley fever in the U.S. each year, and approximately 200 deaths, according to the U.S. Centers for Disease Control (CDC). 

A cake pan filled with marbles is one of the sampling tools designed and built by Tong’s team. This is installed at a U.S. Department of Agriculture (USDA) facility. Credits: NASA/Daniel Tong

Tong and his team are combining NASA satellite data and high-end computer modeling with homemade dust catchers made of pans for baking cakes and marbles. As wind passes over the uneven surface of the marbles, the interrupted flow causes the air to release the dust and spores it’s carrying. As the sediment falls through the layers of marbles to the bottom of the pan, it’s protected from being picked up by wind again, stored safely until the scientists come to collect several weeks’ worth of samples at a time.

The MODIS instrument on NASA’s Terra satellite captured this image of thick plumes of dust stretching from northern Mexico into Texas and New Mexico on March 31, 2017. The Sand and Dust Storm Warning Advisory and Assessment System by the World Meteorological Organization now has a Pan-American node that is incorporating NASA Earth observations like these. Credits: NASA/NASA LANCE/Jeff Schmaltz

Tong says that with more dust storms there will be more instances of Valley fever. For reasons that are not well understood, some people are more susceptible to the effects of Valley fever than others. Only 40 percent of people infected have symptoms, and 8 percent of those go to the hospital. “There’s no vaccine – the fungus lives with you for the rest of your life,” said Tong. “Those infected are paying about US $50,000 per hospital visit, and a quarter of those people have to go ten times or more.”

The team is working with local agencies to place the sensors in areas with frequent dust storms to see where Valley fever might be affecting the most people. Local health agencies like the Pinal County Public Health Department in Arizona and community physicians are already incorporating these data to inform health and safety measures like increased testing and public education.

From NASA written by Lia Poteet/Edited for blog my Marty Coniglio

There’s no D like 3-D

Got your Red-Blue 3D glasses handy? If you do, check out the latest severe storm imagery from NASA.

A 3D composite of GOES-16 and GOES-17 imagery collected every 30 seconds on April 23 and 24, 2021 over a region along the Texas and Oklahoma border. Reports of large hail, high winds, and tornadoes acquired from the NOAA Storm Prediction Center database are labeled on the images. Hail exceeding 3 inches in diameter was reported at 2245, 2305, and 2347 UTC.
Credits: NASA/Kris Bedka and Konstantin Khlopenkov

NASA’s Langely Research Center in Hampton, VA is making 3-D imagery available. Following a severe storm outbreak that brought large hail, high winds and tornadoes to parts of Texas and Oklahoma on April 23 and 24, Langley scientists Kris Bedka and Konstantin Khlopenkov collaborated to create a 3D composite loop of satellite imagery collected by the National Oceanic and Atmospheric Administration’s GOES-17 and GOES-16 satellites (visible above). GOES-17 is in a geostationary orbit (high Earth orbit that allows satellites to match Earth’s rotation) southeast of Hawaii and GOES-16 is in a geostationary orbit approximately due south of Virginia’s Hampton Roads region.

An annotated 3D composite, right, highlighting a variety of features present in the image compared to a single view from GOES-17.
Credits: NASA/Kris Bedka and Konstantin Khlopenkov

Since the two satellites collect images as often as every 30 seconds, and within just a few seconds of one another, combining imagery this way could be a game changer for researchers who study thunderstorms.

“Pairing the high-resolution 3D view with the very rapidly updating imagery really opens up a lot of doors for us in unraveling storm dynamical processes and how they lead to severe weather,” said Bedka.

The detailed 3D perspective also gives scientists a more accurate way to measure cloud height, which they currently do through a bit of inference by taking satellite-observed cloud temperature and matching it to weather prediction models, which provide gridded height and temperature profiles throughout the world. This method works well most of the time, but weather models do not always correctly simulate temperatures near the tops of powerful storms. By also incorporating the best possible 3D rendering of the clouds at the highest possible time intervals, scientists can track patterns visually and better unravel severe-weather processes. Bedka and Khlopenkov are currently working on an algorithm for automating cloud height based on the 3D imagery.

An annotated 3D composite, right, highlighting a variety of features present in the image compared to a single view from GOES-17.
Credits: NASA/Kris Bedka and Konstantin Khlopenkov

Cooperation works

Fengyun meteorological satellites. Green: retired satellites; White: satellites in orbit; Yellow: satellites to-be-launched
National Satellite Meteorological Center of China Meteorological Administration

Weather is a world-wide phenomenon that requires world-wide study and analysis. Scientists around the globe have overcome economic, political, and geographical barriers to work together in learning more about what makes out atmosphere tick. We all benefit from this collaboration.

We have superb NOAA satellites monitoring the Western Hemisphere, but weather is a global system, so we need more data. China began the development of the Fengyun (FY) series of satellites in 1970. As you would expect they have gotten more and more sophisticated with 17 total launches, seven of which are currently in orbit.

“Several approaches for FY satellite data access have been developed for real-time users, scientific researchers, and public users.” said Dr. Peng Zhang, the deputy director of National Satellite Meteorological Center of China Meteorological Administration. “All FY satellite data products are open to the world users and free to download.”

The European Centre for Medium-Range Weather Forecasts (ECMWF) and weather forecasting agencies in China have assimilated the wide array of FY data into many numerical weather prediction (NWP) models. Since the 1990s, coupled meteorological satellites and numerical models have changed the way scientists understand the Earth. You may remember that the ECMWF is famously more accurate in medium and long-range forecasting than the American Global Forecast System (GFS).

While it takes a village to raise a child, it takes a global community of dedicated scientists to produce life-saving weather information.


While much of the country has been “enjoying” the beginning of spring with trees and flowers blooming, things come along a bit later here in the Rocky Mountain West.

The heavy snow in the mountains today is evidence of that!

Plants produce pollen, A LOT of pollen! According to Sheila McCormick, adjunct professor of plant and microbial biology at U.C.-Berkeley “In general, most plants produce much more pollen than is needed. For example, a single corn plant produces 2 [million] to 5 million pollen grains, and an ear of corn has a few hundred seeds. This is especially true for plants that are wind-pollinated.”

Some species of pine can produce up to 5 pounds of pollen in just a few weeks, says Robert Barton, associate dean for extension in the department of forestry and environmental resources at North Carolina State University. Why so much? Well, the more pollen a plant spreads, the better chance it has of successfully seeding offspring.

Matt’s Tree Service in Seattle, WA took this video in May 2019

2011 Tornado Super Outbreak

NOAA Photo Library

Prior to the spring of 2011, the record number of tornadoes in a single month was 542, set in May 2004, while the record for April was only 267. The 2011 Tornado Super Outbreak by contrast, had 362 confirmed tornadoes.

A powerful low-pressure system combined with moist and unstable atmospheric conditions to produce this now-infamous tornado outbreak. Between April 25 and 28, hundreds of tornadoes violently struck the southeastern United States, resulting in roughly $12 billion in damages (2021 dollars) and leaving an estimated 321 people dead.

Until April 2011, three years had passed without a single EF-5 tornado—the strongest rating on the Enhanced Fujita scale, associated with winds in excess of 200 mph. However, this system spawned three EF-5 tornadoes in only a four-day span in addition to 12 EF-4s and 21 EF-3s.

The outbreak challenged and surpassed the records set by almost all previous tornado events, ranking as one of the deadliest and most expensive meteorological disasters on record. April 27, 2011, likely remains the “deadliest day for tornadoes” in the last 85 years. And, the event as a whole killed more people than any outbreak since 1936, when 454 individuals died.

Scientists attribute at least part of the 2011 Super Outbreak’s notoriety to chance. In April 1974, an even more powerful outbreak took place, producing more intense tornadoes—EF-3s to EF-5s—than the 2011 Super Outbreak. But, the 1974 system caused fewer deaths and less monetary damage than its more recent counterpart. Why? Because it struck fewer urban and suburban areas than the 2011 Super Outbreak.

The most ferocious damage of the 2011 outbreak occurred in Alabama. Alone, the state accounted for 69 of the tornadoes and fell victim to the event’s costliest tornado. At its peak, this EF-4 was 1.5 miles—more than 26 football fields—wide, and its winds reached 190 mph. It traversed 80.3 miles, passing through the cities of Tuscaloosa and Birmingham, causing 65 fatalities and over 1,000 injuries. Debris cleanup in Tuscaloosa alone cost $100 million.

Before (left) and after in Tuscaloosa, Alabama, representing damage from April 2011 super tornado outbreak. Before photo courtesy of Google Earth and after photo taken April 29, 2011, from NOAA’s King Air Aircraft, courtesy of the National Geodetic Survey.

The thunderstorm system that created this EF-4 began in Mississippi. It then moved over Alabama, Georgia, and eventually into North Carolina, generating many additional tornadoes along the way.

The tornado outbreak affected almost one third of the nation over its four-day span. While Alabama was hit the hardest, the system had significant effects on Arkansas, Louisiana, Georgia, Tennessee, Virginia, Mississippi, Kentucky, Illinois, Missouri, Ohio, Texas, and Oklahoma, in addition to generally lighter consequences on some of the surrounding states.

Powerful tornadoes struck outside of Alabama as well. In fact, the first EF-5 of the outbreak developed near Smithville, Mississippi. Boasting wind speeds of approximately 205 mph, this tornado destroyed 18 homes and resulted in over a dozen deaths. On April 27, another tornado tracked almost five miles through Chattanooga, Tennessee, causing eight fatalities and injuring ten others.

The total of 362 tornadoes that spawned during this four-day period not only surpassed the previous record for all of April by nearly 100, but also accounted for almost half of the 751 confirmed tornadoes during the month.