Large Storm System To Bring Severe Weather To South; East Coast Expecting Snow Soon

A large storm system is moving through the Great Plains on Monday morning bringing unsettled weather from the Dakotas all the way to the southeastern United States.

Yesterday, more than three dozen damaging storm reports were made, most of them in east-central Texas where hail was larger than a baseball. There were also two reported tornadoes in the Texas panhandle and winds of 60 mph or greater in eastern Texas.

On the northern side of the storm, heavy snow fell around Denver, with anywhere from 5 to 10 inches overnight in the metro area.

The storm system is moving east Monday, and is now stretching from the Northern Plains to the Gulf Coast. To the north, snow is falling in the Dakotas while tornado warnings have been issued for part of the Florida panhandle.

The storm system will move further east Monday afternoon, and will pick up moisture from the Gulf of Mexico. Severe storms will break out from Jacksonville, Florida, to Atlanta; Birmingham, Alabama; and into Nashville, Tennessee.

The biggest threat will be huge damaging hail, tornadoes and wind. Flash flooding is also possible.

The biggest threat for tornadoes will be from Nashville to Birmingham and just west of Atlanta this afternoon and evening.

Developing in the East

As the storm moves east on Tuesday, a coastal low will try to develop in the southern Mid-Atlantic states producing a first wave of rain and snow from Washington, D.C. north into Pennsylvania and west into West Virginia. Several inches of snow is possible just west of Washington, D.C.

By Tuesday night into Wednesday, as the coastal low strengthens, it will produce a second wave of rain and snow, spreading along the I-95 corridor from Washington, D.C. into New York City and Boston.

Models are still not very confident where the low will form and how much snow or rain will fall in the heavily populated I-95 corridor. If major cities get precipitation, it would be mostly be on Wednesday.

The American model isn’t showing much snow for the major cities — maybe a dusting to 1 to 2 inches on Wednesday.

The European model has a different forecast with heavy snow accumulations for the major Northeast cities, but ABC News meteorologists predict the model is probably overdoing these amounts.

The short-term American model is showing the storm missing Washington, D.C., Philadelphia and New York City, with maybe some snow accumulations along the Mid-Atlantic coast and into Cape Cod.

It could go either way, but confidence is growing that some sort of storm system will form along the East Coast.

Madagascar Hit By Another Tropical Cyclone

Tropical Cyclone Eliakim has battered Madagascar with strong winds and torrential rain.

The storm made landfall on the peninsula of Masoala in northeastern Madagascar and tracked southwards along the coast.

Strong winds battered the island and torrential rain fell on already-saturated land, triggering landslides and flooding.

The cyclone comes less than two weeks after Dumazile grazed the east coast of the island nation.

Both storms hit Toamasina, Madagascar’s second largest city. Images on social media showed widespread flooding with roads and homes inundated.

According to local media, at least one person has been killed by Eliakim and many more have been injured.

The storm is now weakening as it moves southeast, away from Madagascar.

Suomi NPP Satellite Sees Tropical Cyclone Hola Over Vanuatu

On Mar. 8 at 0230 UTC (Mar. 7 at 9:30 p.m. EST) the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite showed the center of Hola was located southwest of the Pacific island nation of Vanuatu. The VIIRS image showed a well-rounded circulation center with bands of powerful thunderstorms wrapping into the center. The VIIRS image showed the northern and eastern quadrants of the storm extended over Vanuatu.

On March 8, warnings were in effect in Vanuatu and a pre-alert was posted for New Caledonia. In Vanuatu a tropical cyclone warning is in force for Shefa province. In New Caledonia the territory is on pre-alert, with the exception of Ouvéa, Maré and Lifou, which are on tropical cyclone alert 1. The pre-alert is expected to be upgraded to alert 2 within a day.

At 4 a.m. EST (0900 UTC) on March 8, Hola’s maximum sustained winds were near 109 mph (95 knots/175 kph). It was centered near 17.6 degrees south latitude and 165.4 degrees east longitude. That’s about 166 nautical miles west of Port Vila, Vanuatu. Hola was moving to the south-southwest at 4.6 mph (4 knots/7.4 kph).

The Joint Typhoon Warning Center forecast calls for Hola to move to the south-southeast over the next few days. The storm will intensify to 115 knots east of New Caledonia. Hola is then expected to weaken and become extra-tropical on approach to the North Island of New Zealand.

Storm Waves Can Move Boulders We Thought Only Tsunamis Had The Power To Shift

It’s not just tsunamis that can change the landscape: storms shifted giant boulders four times the size of a house on the coast of Ireland in the winter of 2013-14, leading researchers to rethink the maximum energy storm waves can have — and the damage they can do.

In a new paper in Earth Science Reviews, researchers from Williams College in the US show that four years ago, storms moved huge boulders along the west coast of Ireland. The same storms shifted smaller ones as high as 26 meters above high water and 222 meters inland. Many of the boulders moved were heavier than 100 tons, and the largest moved was 620 tons — the equivalent of six blue whales or four single-storey houses.

It was previously assumed that only tsunamis could move boulders of the size seen displaced in Ireland, but the new paper provides direct evidence that storm waves can do this kind of work. According to the UN, about 40 percent of the world’s population live in coastal areas (within 100 meters of the sea), so millions of people are at risk from storms. Understanding how those waves behave, and how powerful they can be, is key for preparation. It is therefore important to know the upper limits of storm wave energy, even in areas where these kinds of extreme wave energies are not expected.

“The effect of the storms of winter 2013-14 was dramatic,” said Dr. Rónadh Cox, Professor and Chair of Geosciences at Williams College and lead author of the study. “We had been studying these sites for a number of years, and realised that this was an opportunity to measure the coastal response to very large storm events.”

In the summer after the storms, Prof. Cox and a team of seven undergraduate students from Williams College surveyed 100 sites in western Ireland, documenting with photos the displacement of 1,153 boulders. They measured the dimensions and calculated the mass of each boulder. They knew where 374 of the boulders had come from, so for those they also documented the distance travelled. The largest boulder, at 237-239 m3 was an estimated 620 tons; the second biggest, at 180-185 m3, was about 475 tons. These giant rocks were close to sea level (although above the high tide mark). At higher elevations, and at greater distances inland, smaller boulders moved upwards and inland.

Analysis of this information showed that the waves had most power at lower elevations and closer to the shore. While this may not be surprising, the sheer energy of the waves and their ability to move such large boulders was — and this evidence proves that not only tsunami but also storm waves can move such large objects.

“These data will be useful to engineers and coastal scientists working in other locations,” said Prof. Cox. “Now that we know what storm waves are capable of, we have much more information for policy makers who are responsible for preparing coastal communities for the impact of high-energy storms.”

Storm Brings Near Blizzard Conditions To Much Of Nebraska

A winter storm has brought near blizzard conditions to much of Nebraska.

The National Weather Service says more than 10 inches (26 centimeters) has already fallen on North Platte in western Nebraska, and near zero visibility has been reported near Cambridge.

Weather service meteorologist Aaron Mangels said around 5:30 a.m. that snow was just starting to fall on Hastings in south-central Nebraska, and he expected 5 to 6 inches (13 to 15 centimeters) to accumulate by the storm’s exit around 3 p.m.

The Nebraska Transportation Department websites shows around three-quarters of the state’s roads are covered with snow, but none is listed as impassable. Authorities are encouraging people to avoid any highway travel.

Jet Stream Changes Since 1960s Linked To More Extreme Weather

Increased fluctuations in the path of the North Atlantic jet stream since the 1960s coincide with more extreme weather events in Europe such as heat waves, droughts, wildfires and flooding, reports a University of Arizona-led team.

The research is the first reconstruction of historical changes in the North Atlantic jet stream prior to the 20th century. By studying tree rings from trees in the British Isles and the northeastern Mediterranean, the team teased out those regions’ late summer weather going back almost 300 years—to 1725.

“We find that the position of the North Atlantic Jet in summer has been a strong driver of climate extremes in Europe for the last 300 years,” Trouet said.

Having a 290-year record of the position of the jet stream let Trouet and her colleagues determine that swings between northern and southern positions of the jet became more frequent in the second half of the 20th century, she said.

“Since 1960 we get more years when the jet is in an extreme position.” Trouet said, adding that the increase is unprecedented.

When the North Atlantic Jet is in the extreme northern position, the British Isles and western Europe have a summer heat wave while southeastern Europe has heavy rains and flooding, she said.

When the jet is in the extreme southern position, the situation flips: Western Europe has heavy rains and flooding while southeastern Europe has extreme high temperatures, drought and wildfires.

“Heat waves, droughts and floods affect people,” Trouet said. “The heat waves and drought that are related to such jet stream extremes happen on top of already increasing temperatures and global warming—it’s a double whammy.”

Extreme summer weather events in the American Midwest are also associated with extreme northward or southward movements of the jet stream, the authors write.

“We studied the summer position of the North Atlantic jet. What we’re experiencing now in North America is part of the same jet stream system,” Trouet said.

This winter’s extreme cold and snow in the North American Northeast and extreme warmth and dryness in California and the American Southwest are related to the winter position of the North Pacific Jet, she said.

The paper, “Recent enhanced high-summer North Atlantic Jet variability emerges from three-century context,” by Trouet and her co-authors Flurin Babst of the Swiss Federal Research Institute WSL in Birmensdorf and Matthew Meko of the UA is scheduled for publication in Nature Communications on Jan. 12. The U.S. National Science Foundation and the Swiss National Science Foundation funded the research.

“I remember quite vividly when I got the idea,” Trouet said. “I was sitting in my mom’s house in Belgium.”

While visiting her family in Belgium during the very rainy summer of 2012, Trouet looked at the newspaper weather map that showed heavy rain in northwestern Europe and extreme heat and drought in the northeastern Mediterranean.

“I had seen the exact same map in my tree-ring data,” she said. The tree rings showed that hot temperatures in the Mediterranean occurred the same years that it was cool in the British Isles—and vice versa.

The part of an annual tree ring that forms in the latter part of the growing season is called latewood. The density of the latewood in a particular tree ring reflects the August temperature that year.

Other investigators had measured the annual latewood density for trees from the British Isles and the northeastern Mediterranean for rings formed from 1978 back to 1725.

Because August temperatures in those two regions reflect the summer position of the North Atlantic jet stream, Trouet and her colleagues used those tree-ring readings to determine the historical position of the jet stream from 1725 to 1978. For the position of the jet stream from 1979 to 2015, the researchers relied on data from meteorological observations.

“There’s a debate about whether the increased variability of the jet stream is linked to man-made global warming and the faster warming of the Arctic compared to the tropics,” Trouet said.

“Part of the reason for the debate is that the data sets used to study this are quite short—1979 to present. If you want to see if this variability is unprecedented, you need to go farther back in time—and that’s where our study comes in.”

With the discovery of much older trees in the Balkans and in the British Isles, Trouet hopes to reconstruct the path of the North Atlantic jet stream as much as 1,000 years into the past. She is also interested in reconstructing the path of the North Pacific jet stream, which influences the climate and weather over North America.

New Study Reveals Strong El Nino Events Cause Large Changes In Antarctic Ice Shelves

A new study published Jan. 8 in the journal Nature Geoscience reveals that strong El Nino events can cause significant ice loss in some Antarctic ice shelves while the opposite may occur during strong La Nina events.

El Niño and La Niña are two distinct phases of the El Niño/Southern Oscillation (ENSO), a naturally occurring phenomenon characterized by how water temperatures in the tropical Pacific periodically oscillate between warmer than average during El Niños and cooler during La Niñas.

The research, funded by NASA and the NASA Earth and Space Science Fellowship, provides new insights into how Antarctic ice shelves respond to variability in global ocean and atmospheric conditions.

The study was led by Fernando Paolo while a PhD graduate student and postdoc at Scripps Institution of Oceanography at the University of California San Diego. Paolo is now a postdoctoral scholar at NASA’s Jet Propulsion Laboratory. Paolo and his colleagues, including Scripps glaciologist Helen Fricker, discovered that a strong El Niño event causes ice shelves in the Amundsen Sea sector of West Antarctica to gain mass at the surface and melt from below at the same time, losing up to five times more ice from basal melting than they gain from increased snowfall. The study used satellite observations of the height of the ice shelves from 1994 to 2017.

“We’ve described for the first time the effect of El Niño/Southern Oscillation on the West Antarctic ice shelves,” Paolo said. “There have been some idealized studies using models, and even some indirect observations off the ice shelves, suggesting that El Niño might significantly affect some of these shelves, but we had no actual ice-shelf observations. Now we have presented a record of 23 years of satellite data on the West Antarctic ice shelves, confirming not only that ENSO affects them at a yearly basis, but also showing how.”

The opposing effects of El Niño on ice shelves – adding mass from snowfall but taking it away through basal melt – were at first difficult to untangle from the satellite data. “The satellites measure the height of the ice shelves, not the mass, and what we saw at first is that during strong El Niños the height of the ice shelves actually increased,” Paolo said. “I was expecting to see an overall reduction in height as a consequence of mass loss, but it turns out that height increases.”

After further analysis of the data, the scientists found that although a strong El Niño changes wind patterns in West Antarctica in a way that promotes flow of warm ocean waters towards the ice shelves to increase melting from below, it also increases snowfall particularly along the Amundsen Sea sector. The team then needed to determine the contribution of the two effects. Is the atmosphere adding more mass than the ocean is taking away or is it the other way around?

“We found out that the ocean ends up winning in terms of mass. Changes in mass, rather than height, control how the ice shelves and associated glaciers flow into the ocean,” Paolo said. While mass loss by basal melting exceeds mass gain from snowfall during strong El Niño events, the opposite appears to be true during La Niña events.

Over the entire 23-year observation period, the ice shelves in the Amundsen Sea sector of Antarctica had their height reduced by 20 centimeters (8 inches) a year, for a total of 5 meters (16 feet), mostly due to ocean melting. The intense 1997-98 El Nino increased the height of these ice shelves by more than 25 centimeters (10 inches). However, the much lighter snow contains far less water than solid ice does. When the researchers took density of snow into account, they found that ice shelves lost about five times more ice by submarine melting than they gained from new surface snowpack.

“Many people look at this ice-shelf data and will fit a straight line to the data, but we’re looking at all the wiggles that go into that linear fit, and trying to understand the processes causing them,” said Fricker, who was Paolo’s PhD adviser at the time the study was conceived. “These longer satellite records are allowing us to study processes that are driving changes in the ice shelves, improving our understanding on how the grounded ice will change,” Fricker said.

“The ice shelf response to ENSO climate variability can be used as a guide to how longer-term changes in global climate might affect ice shelves around Antarctica,” said co-author Laurie Padman, an oceanographer with Earth & Space Research, a nonprofit research company based in Seattle. “The new data set will allow us to check if our ocean models can correctly represent changes in the flow of warm water under ice shelves,” he added.

Melting of the ice shelves doesn’t directly affect sea level rise, because they’re already floating. What matters for sea-level rise is the addition of ice from land into the ocean, however it’s the ice shelves that hold off the flow of grounded ice toward the ocean.

Understanding what’s causing the changes in the ice shelves “puts us a little bit closer to knowing what’s going to happen to the grounded ice, which is what will ultimately affect sea-level rise,” Fricker said. “The holy grail of all of this work is improving sea-level rise projections,” she added.