Christmas Tornadoes Roll Across South and Midwest

A total of 24 tornadoes were reported in seven states: Tennessee, Mississippi, Illinois, Indiana, Alabama, Arkansas and Michigan.  10 people were killed in Mississippi, Tennessee and Arkansas as storms spawned rare Christmas tornadoes. A large tornado tore a 100-mile path through northern Mississippi, demolishing or heavily damaging dozens of homes and other buildings in a six-county area before plowing into western Tennessee. Officials blamed the severe weather for injuring scores of others Wednesday and destroying dozens of cars, homes and businesses. In the worst-hit communities, search parties hunted for missing people and volunteers helped clear debris on a day often reserved for gift wrapping and last-minute shopping. Unseasonably warm weather is the main cause. The National Weather Service forecast isolated severe thunderstorms from the mid-Atlantic region to the Gulf Coast and record warmth to New York.

“To have long-track tornadoes in December in the Memphis forecast area is an unusual event,” said Jonathan Howell, a meteorologist in the NWS Memphis office. "We typically don't have tornadoes of that intensity that impact the area, but we're dealing with this unusally warm weather pattern." The line of storms are moving east today (Thursday) and will bring heavy rain and thunderstorms to Georgia, Florida, Virginia, and the Carolinas. The threat of severe weather just before Christmas is unusual, but not unprecedented, said Greg Carbin, a meteorologist at the national Storm Prediction Center. Exactly a year ago, twisters hit southeast Mississippi, killing five people and injuring dozens of others.

Research provide insights on recent 'unprecedented' melting of Greenland's interior ice sheet.

NASA observations show the dynamism of Greenland's Ice sheet in the changing elevation of its surfaces. Recent analysis of seven years of readings from NASA's ICESat satellite and four years of laser and and ice-penetrating radar data from NASA's airborne mission Operation IceBridge shows the changes taking place.

In the animation featured below, the colors shown on the surface of the ice sheet represent the accumulated change in elevation since 2003. The light yellow over the central region of the ice sheet indicates a slight thickening due to snow. This accumulation, along with the weight of the ice sheet, pushes ice toward the coast. Thinning near coastal regions, shown in green, blue and purple, has increased over time and now extends into the interior of the ice sheet where the bedrock topography permits. As a result, there has been an average loss of 300 cubic kilometers of ice per year between 2003 and 2012.

This animation portrays the changes occurring in the surface elevation of the ice sheet since 2003 in three drainage regions: the southeast, the northeast and the Jakobshavn regions. In each region, the time advances to show the accumulated change in elevation from 2003 through 2012.

“The retreat of these glacier  is likely to increase sea-level rise for decades to come, collapse of the entire basin is going to take a long time, But it’s a process, when you start, you don’t see the glacier recovering.”

Published on Mar 27, 2014

Arctic Report Card: Arctic warming more rapidly than rest of planet.

Highlights of the Arctic Report Card:

  • Average annual surface air temperature anomaly (+1.3°C) over land north of 60°N for October 2014-September 2015 was the highest in the observational record beginning in 1900; this represents a 2.9°C increase since the beginning of the 20th Century.
  • Average air temperature anomalies in all seasons between October 2014 and September 2015 were generally positive throughout the Arctic, with extensive regions exceeding +3°C relative to a 1981-2010 baseline.
  • Anomalously warm conditions from November 2014 through June 2015 in Alaska were caused by weather patterns that advected warm mid-latitude air northward from the northeast Pacific Ocean. Anomalously warm Arctic conditions during spring (April, May, June) 2015 across central Eurasia were also due to southerly winds.
  • Strong connections between the Arctic and the mid-latitudes were also seen in late winter-early spring (February-April) 2015, when cold air advected south-eastward from the central Arctic resulted in major negative temperature anomalies over eastern North America.
  • Melt area in 2015 exceeded more than half of the ice sheet on July 4th for the first time since the exceptional melt events of July 2012, and was above the 1981-2010 average on 54.3% of days (50 of 92 days).
  • The length of the melt season was as much as 30-40 days longer than average in the western, northwestern and northeastern regions, but close to and below average elsewhere on the ice sheet.
Surface air temperatures over the Arctic have climbed 5.2 degrees Fahrenheit since the beginning of the 20th Century – more than twice the level of warming experienced elsewhere on Earth, scientists said Tuesday in an annual report. Between October 2014 and September 2015, the average surface air temperature in the region was 2.3 degrees Fahrenheit higher than the baseline average set between 1981 to 2010 — the highest temperature in 115 years, said U.S. Army Corps of Engineers researcher Jackie Richter-Menge.
“In general, air temperatures in all seasons were above average throughout the Arctic, with extensive regions exceeding 5.4 degrees Fahrenheit over the 1981-2010 baseline,” Richter-Menge told reporters at the American Geophysical Union conference in San Francisco.
The warmer air contributed to changes in the amount of Arctic sea ice, which peaked on Feb. 25 – 15 days earlier than average. This winter ice pack was the smallest on record since 1979.
In addition, only 3 percent of the ice cover in February and March 2015 was so-called “old ice,” which is older than four years. New, first-year ice made up 70 percent of the pack, the research showed. Three decades ago, 20 percent of the ice pack was more than four years old and just 35 percent of the pack was first-year ice, Richter-Menge said. “Given consistent projections of continued warming temperatures, we can expect to see continued widespread and sustained change throughout the Arctic environmental system,” she added.

Greenland is loosing ice mass quite rapidly for years, as this chart indicates:
Cumulative change in the total mass of the Greenland Ice Sheet
Cumulative change in the total mass (in Gigatonnes, Gt) of the Greenland Ice Sheet between April 2002 and April 2015
The changing Arctic is impacting the rest of the planet as well, said Rick Spinrad, chief scientist with the National Oceanic and Atmospheric Administration (NOAA), which released the 2015 Arctic Report Card
“What happens in the Arctic doesn’t stay in the Arctic,” Spinrad said. “What happens matters to all of us from strategic, climate and national security perspectives.”