NASA animation tracks the end of Tropical Storm Delta

Posted on

NASA animation tracks the end of Tropical Storm Delta  
NASA’s Terra satellite provided a visible image to forecasters of Tropical Storm Delta moving through the southeastern U.S. on Oct. 11 at 1:30 p.m. EDT. At the time of the image, the storm was centered over northern Alabama. Credit: NASA Worldview, Earth Observing System Data and Information System (EOSDIS).

NASA’s Terra satellite obtained visible imagery as Tropical Storm Delta made landfall in Louisiana and moved northeastward soaking the U.S. southeast and Mid-Atlantic states.

NASA satellite view: Delta’s organization

The Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Terra satellite captured a visible image of Tropical Storm Delta on Oct. 11 at 1:30 p.m. EDT. The storm still appeared circular in imagery. At the time, it was centered over northern Alabama. At the time Terra passed overhead, Delta had weakened to a tropical depression with maximum sustained winds near 25 mph (35 kph).

Visible imagery from NASA’s Terra satellite captured from Oct. 9 to Oct. 12 were compiled into an animation. The animation showed the landfall and movement of Tropical Storm Delta. Delta dissipated over the southeastern U.S. and its remnants moved into the Atlantic states. The animation was created using NASA’s Worldview product at NASA’s Goddard Space Flight Center in Greenbelt, Md.

Delta’s landfall on Oct. 9

National Weather Service Doppler radar imagery, Air Force Reserve Hurricane Hunter aircraft data, and surface observations indicated on Oct. 9 that Delta made landfall near Creole, Louisiana, around 7 p.m. EDT with estimated maximum sustained winds of 100 mph (155 kph). Delta was a category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale.

NASA animation tracks the end of Tropical Storm Delta
This animation of visible imagery from NASA Terra satellite shows the landfall and movement of Tropical Storm Delta from Oct. 9 to Oct. 12. Delta dissipated over the southeastern U.S. and its remnants moved into the Atlantic


Past tropical forest changes drove megafauna and hominin extinctions

Posted on

Past tropical forest changes drove megafauna and hominin extinctions
Artist’s reconstruction of a savannah in Middle Pleistocene Southeast Asia. In the foreground Homo erectus, stegodon, hyenas, and Asian rhinos are depicted. Water buffalo can be seen at the edge of a riparian forest in the background Credit: Peter Schouten

In a paper published today in the journal Nature, scientists from the Department of Archaeology at MPI-SHH in Germany and Griffith University’s Australian Research Centre for Human Evolution have found that the loss of southeast Asian grasslands was instrumental in the extinction of many of the region’s megafauna, and probably of ancient humans too.

“Southeast Asia is often overlooked in global discussions of megafauna extinctions,” says Associate Professor Julien Louys, who led the study, “But in fact, it once had a much richer mammal community full of giants that are now all extinct.”

By looking at stable isotope records in modern and fossil mammal teeth, the researchers were able to reconstruct whether past animals predominately ate tropical grasses or leaves, as well as the climatic conditions at the time they were alive. “These types of analyses provide us with unique and unparalleled snapshots into the diets of these species and the environments in which they roamed,” says Dr. Patrick Roberts of the MPI-SHH, the other corresponding author of this study.

The researchers compiled these isotope data for fossil sites spanning the Pleistocene, the last 2.6 million years, as well as adding over 250 new measurements of modern Southeast Asian mammals representing species that had never before been studied in this way.

They showed that rainforests dominated the area from present-day Myanmar to Indonesia during the early part of the Pleistocene but began to give way to more grassland environments. These peaked around 1 million years ago, supporting rich communities of grazing megafauna such as the elephant-like stegodon that, in


Tropical Storm Gamma moves inland over Yucatan Peninsula

Posted on

Oct. 3 (UPI) — The record-breaking nature of the 2020 Atlantic Tropical Season continues as Tropical Storm Gamma strikes the Yucatan Peninsula of Mexico.

Gamma became a tropical storm, and thus gained its name, on Friday evening as it strengthened in the northwestern Caribbean Sea. In doing so, Tropical Storm Gamma became only the second of its name to exist in Atlantic Basin history, and the earliest ever, beating out the Gamma of 2005.

At 12:45 p.m. EST on Saturday, Gamma made landfall near Tulum, Mexico, as a strong tropical storm.

The U.S. National Hurricane Center said that a weather station at Xel-Ha Park, along the Yucatan coast just north of Tulum, reported sustained winds of 55 mph (89 km/h) and wind gusts up to 68 mph (109 km/h).

On the island of Cozumel, just offshore from the Yucatan Peninsula, wind gusts of 40 mph (64 km/h) were reported early Saturday afternoon.

Gamma is expected to continue to batter the Yucatan Peninsula through the weekend with heavy rain and gusty winds before shifting into the Gulf of Mexico.

On Friday, tropical storm watches and warnings were issued for parts of the Yucatan Peninsula.

The Governor of the state of Quinatana Roo, which contains cities like Tulum, Playa del Carmen, and Cancun, advised on Twitter that residents shelter at home and report emergencies to the appropriate authorities.

According to Noticaribe, one of the hardest-hit areas thus far is Playa del Carmen, where the State Coordination of Civil Protection issued a red alert on Saturday morning, due to Gamma’s impending impacts.

Reports of fallen trees, blackouts and flooding in main streets were noted by several emergency agencies in the city.

Just to the north, in Puerto Morelos, the local government set up two temporary shelters. Fire fighters, public services and civil protection


Tropical Atlantic begins to awaken as October looms

Posted on

Twenty-three named storms have whirled their way across the Atlantic basin so far this season, exhausting the naming list used by meteorologists and forcing then to dip into the Greek alphabet for only the second time in history. While the majority of systems have been relatively weak and unremarkable, some, like Category 4 Laura and Category 2 Sally, have caused significant damage.

Now, October promises to bring another round of weather that must be watched, as a combination of large-scale atmospheric circulations overlap to enhance tropical weather activity. The focus is already on the Caribbean and Gulf of Mexico, which tend to prove to be autumn hot spots for storms. In fact, one or two weather systems there could already be in the works.

System to watch for the Yucatán Peninsula; heavy rainfall possible in Florida

On Wednesday, a strip of low pressure oriented from south to north was sauntering westward across the eastern Caribbean. Satellite imagery reveals a few thunderstorms along that axis of low pressure, and computer models indicate that one clustering of downpours may eventually acquire some spin and serve as the impetus for tropical formation.

It’s a good bet that something will form or at least try to form, but the wild card exists in where along that low pressure “trough” it will be. Some models, like the American GFS and the Canadian model, show a slightly weaker, southerly solution, with a low pressure system clipping or passing over the northern Yucatán Peninsula this weekend. That would bring 3 to 6 inches of rain, with localized eight-inch amounts, to northern Quintana Roo and the Yucatán states of Mexico.

Other models, including the European model, fringe the Yucatán Peninsula with that lobe of spin. The German ICON model depicts an even farther north solution, which would yield


Caribbean, Gulf of Mexico areas to watch for tropical storms

Posted on

Historically, hurricane season peaks about Sept. 10, activity typically in top gear leading into October. But this year’s hyperactive September came screeching to a halt Friday, when Teddy and Beta in the Atlantic and Lowell in the Pacific fizzled or lost tropical characteristics entirely. Since then, the world’s oceans have been virtually silent. But they won’t be for long.

A large zone of rising air at mid-to-upper levels of the atmosphere will soon overspread the Atlantic from the west, at the same time as global circulations favor an uptick in shower and thunderstorm activity. The two factors could overlap to bring about a renewal in tropical busyness.

An area to watch

The National Hurricane Center is already monitoring one area in the northwest Caribbean that could prove problematic in the coming week. The center estimates a 50-percent chance that tropical development will occur sometime in the next five days.

A strip of clumped thunderstorm activity can be seen on satellite north of Venezuela, west of the Lesser Antilles, associated with a weak westward-moving wave at the mid-levels of the atmosphere. The system is rather diffuse, but models hint that a more concentrated lobe of vorticity, or spin, could consolidate along its southern flank.

Uncertainty is a bit greater than normal when it comes to this system, which will probably arrive north of Honduras in the extreme northwest Caribbean by Friday. After that, the details become hazy.

If that blob of spin ends up forming along the central or northern part of that axis of disturbed weather, then the system could latch onto steering currents that would eventually bring it west of Cuba and perhaps into the Gulf of Mexico. But if it becomes established farther south, the system could end up being steered into the Yucatán Peninsula and becoming