WEEK SIX: 6-10 March 2017

ITEMS OF INTEREST

• Tracking the lunar shadow on Earth from space -- Instruments onboard several Earth-orbiting satellites were able to track the path of the Moon's shadow as it raced across the South America and the South Atlantic Ocean on Sunday, 26 February 2017, as part of the annular solar eclipse. The images obtained from the EPIC (Earth Polychromatic Imaging Camera) instrument onboard NOAA's Deep Space Climate Observatory (DSCOVR) satellite were pieced together to form an animation. The DSCOR satellite is located approximately one million miles from Earth at the L1 point, a neutral gravity point between Earth and the Sun. A similar animation, but with more detail, was made from the assembling of images from the MODIS instruments on NASA's Terra and Aqua satellites and the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the NASA/NOAA Suomi NPP satellite. These three satellites are in a low-altitude polar orbit with an altitude above Earth of approximately 440-500 miles. The Earth-Sun geometry of the annular solar eclipse created a red-orange ring (or "Ring of Fire") on the satellite images because the Earth was not able to obscure all of the Sun, even at the height of the eclipse. [NASA Earth Observatory]
• Cherry Blossom Watch in Washington, DC -- Many tourists descend upon Washington, DC during the spring to view the sights, including the blossoming cherry trees that line the Tidal Basin along the Potomac River. This year marks the 90th anniversary of the first Cherry Blossom Festival. The National Park Service operates a website that reports the status of the cherry blossoms in anticipation of the timing of peak bloom. According to their most recent forecast, experts expect that the trees should be at peak bloom between 14-17 March 2017, due to the relatively mild weather across the Middle Atlantic States. Because of this forecast, the start of the 2017 National Cherry Blossom Festival has been is now scheduled to commence on Wednesday, 15 March, which is five days earlier than previously scheduled. The festival will run through Sunday, 16 April 2017. The current dates of anticipated bloom are much earlier than the average peak bloom date of 2 April. This website also has a listing of the phenological observations for past bloom dates over the past 24 years.
  A four-minute video "Climate Change and Cherry Blossoms in Washington, DC" is available on the National Park Service website and describes how the earlier blossoming of cherry trees indicate a changing climate.
  A graph of the occurrence of the dates of peak cherry blossom occurrence in Washington, DC beginning in 1921 and running through last year is also available. Examination of this graph indicates that the anticipated peak bloom could rival the record earliest occurrence on 15 March 1990.
• Viewing atmospheric circulation in three-dimensions -- Read this week's Supplemental Information.. In Greater Depth for information concerning the average circulation in the lower and upper troposphere.
• Time change -- Daylight Saving Time will go into effect next Sunday morning (12 March 2017) for essentially the entire nation -- the exceptions include Arizona, Hawaii, Puerto Rico and about 18 counties in Indiana. These changes have been mandated by the U.S. Congress in the Energy Policy Act of 2005, which extended Daylight Saving Time across the nation, with the start on the second Sunday in March and end on the first Sunday in November (5 November 2017). In other words, following the old adage of "spring ahead, fall behind", you will need to turn your clocks ahead by one hour to conform with the local time observance. Most of Canada also observes Daylight Saving Time changes at the same time [National Research Council Canada].
  What does this time change mean to you (other than later sunsets)? Contrary to a popular belief that has surfaced at times, the change from Standard to Daylight Saving Time does not add an extra hour of daylight to the day nor does it affect weather patterns. While the weather will not change because of the time change, the times when you will be able to obtain weather charts will now be one hour later. The reason is that the National Weather Service operates on "Z time" (variously called Greenwich Mean Time or Universal Coordinated Time) which does not observe Daylight Saving Time, and the charts are still produced and transmitted at the same Z time.
• A Reminder -- Next week (beginning Monday, 13 March 2017) is Spring vacation week for DataStreme Earth Climate System. All the familiar DataStreme ECS products will be available throughout the week. The Investigation and Supplemental Information files from this week will remain on the DataStreme Atmosphere ECS RealTime Climate Portal and the Concept of the Week will be repeated for those who are on spring break. If you have questions, check with your mentor.

CURRENT CLIMATE MONITORING

• Record high temperature in Antarctica is finally recognized -- During the last week the World Meteorological Organization (WMO) announced that after evaluation by an international committee of polar scientists, a new record high temperature for the entire continent of Antarctica and its surrounding islands is recognized. This new record high temperature of 63.5 degrees Fahrenheit was observed at an Argentine Esperanza Research Station on 24 March 2015, eclipsing the previous record high of 59 degrees. The official WMO recognition of this record high temperature appears on their World Weather & Climate Extremes Archive website maintained by Arizona State University. [Science Daily]
• Sections of the nation hit by record late season "heat wave" -- An article was posted in the NOAA ClimateWatch Magazine that discusses the four-day span in late February 2017 across the central and eastern United States where high temperatures reached record levels not previously seen for meteorological winter (December through February). The National Centers for Environmental Information reported that 408 total monthly high temperatures records were set across the nation in February. A combination of above-average sea surface temperatures across the Gulf of Mexico and western Atlantic and southerly winds transporting the warm air northward into the Midwest and Northeast contributed to the record high temperatures. While the southern, central and eastern states had above to much above average temperatures, the northern and western sections of the nations had below average temperatures. [NOAA Climate.gov News]
• Unusually warm February weather indicates spring is arriving early this year east of the Rockies -- The USA National Phenology Network (USA-NPN), which is sponsored by NOAA, NASA and the US Fish and Wildlife Service, has been following the northward progress of leafy plants as indicated by an animation of the "Daily Spring Index Leaf Anomaly" over a 8-week period. These maps compiled by USA-NPN show that spring was arriving between two and three weeks early across the South and Southeast, running from southern Texas eastward to Georgia and northward to Virginia. USA-NPN is a nationwide network consisting of citizen scientists, government agencies, non-profit groups, educators and students willing to monitor the impacts of climate change on plants and animals in the United States. Researchers with the USA-NPN are using Spring Indices models based on nationwide field observations collected about when sufficient heat has accumulated in a region to initiate leafing and blooming in lilacs and honeysuckles, two common and temperature-sensitive flowering plants. Recent daily temperature data are obtained from the NOAA's National Weather Service, along with historical daily data from a database maintained by Oregon State University to create national-scale daily maps with a 2-mile resolution. [USGS News]
  Concern has been raised at the US Department of Agriculture (USDA) Midwest Climate Hub that the above-normal temperatures across the Midwest during February could have a detrimental effect upon many of the region's crops as the early warmth could cause the plants that represent cash crops (alfalfa and fruit trees) could break dormancy and start entering the frost-sensitive phase of budding and blooming. The abnormal, early-spring arrival across the Midwest has been observed by the USA National Phenology Network (USA-NPN). [USDA Climate Hubs News]
• Monitoring food shortages in the parched Greater Horn of Africa -- A map of the Evaporative Stress Index across eastern Africa generated from data collected by satellite sensors shows the extent of drought conditions across the Greater Horn of Africa. This ESI is an indicator of evapotranspiration based upon surface temperatures and leaf area index obtained from the MODIS instruments on NASA's Terra and Aqua satellites and the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the NASA/NOAA Suomi NPP satellite. The current ESI map confirms the extent of the drought across the Greater Horn of Africa, which has led to near famine in some of the countries. [NASA Earth Observatory]

CLIMATE FORECASTS

• Canadian national seasonal outlook issued -- Forecasters with Environment Canada issued their outlooks for temperature and precipitation across Canada for meteorological spring, or the three months of March through May 2017. Their temperature outlook indicates that western sections of Canada, extending from the British Columbia coast northward across the Yukon and Northwestern Territories, could experience below normal (1981-2010) temperatures for these three months. Several small areas along the western shore of Hudson Bay and in Atlantic Canada also could have below average temperatures. Conversely, sections of southeastern Canada extending from the Great Lakes eastward to the Maritime Provinces, as well as eastern sections of the Canadian Archipelago could see above average spring temperatures. Elsewhere across Canada, near average temperatures were anticipated.
  The Canadian precipitation outlook for Spring 2017 indicates that many areas across the Prairie Provinces and the region from the Great Lakes and the St. Lawrence Valley to the Maritime Provinces could experience above average precipitation for the next three months. Widely scattered sections of northern Canada could have below average precipitation. Elsewhere, near average spring precipitation should occur.
  [Note for comparisons and continuity with the three-month seasonal outlooks of temperature and precipitation generated for the continental United States and Alaska by NOAA's Climate Prediction Center, one would need to use Environment Canada's probabilistic forecasts for temperature and precipitation.]
• New forecast model using satellite data is intended to improve forecasts of summer Arctic sea ice -- Researchers at NASA's Goddard Space Flight Center have developed a new forecast model that utilizes satellite measurements of Arctic sea ice extent and melt onset, or the time at which sea ice starts melting and open water appears. This new model, which will be run this spring, is intended to help forecasters make better estimates of the summer ice across various sections of the Arctic Ocean, such as in the Beaufort and Chukchi Seas to the north of Alaska. In addition, the scientists should be able to use their predictions of sea ice minimum extent to assess changing climate conditions in the arctic. [NASA Goddard Space Flight Center Feature]
• Flow of Colorado River shrinks as air temperatures rise -- Researchers at Colorado State University and the University of Arizona warn that as air temperatures rise across the Southwestern US during early years of the 21st century, the flow of the Colorado River has been reduced by an average of nearly 20 percent per year between 2000 and 2014. At least one-third of the decline appears likely to be due to warming. If temperatures continue to rise because of continued unabated greenhouse gas emissions, substantial warming would continue, meaning 21st century flow reductions of 35% or more. Although more precipitation would reduce the flow loss, a lack of an increase in precipitation to date, along with a large mega-drought threat, would reinforce the risk of a large flow loss. [University of Arizona News]

CLIMATE FORCING

• Importance of the "MJO" to large-scale precipitation patterns is assessed -- A tropical climate expert at the North Carolina Institute for Climate Studies wrote a feature for the Beyond the Data blog that describes how a large eastward moving pattern called the "Madden-Julian Oscillation" or MJO affects the precipitation patterns not only in the tropics, but also in midlatitudes. Unlike ENSO patterns that are generally fixed in the tropics for months, the MJO with its enhanced convective phase and suppressed convective phase traverses the Earth from west to east in the tropics, returning to its initial starting point in 30 to 60 days, on average. Emphasis is placed upon recent cloud and wind patterns and their relationship to the MJO. [Editor's note: The reference to butterflies in the beginning of this blog is to the "butterfly effect" that was proposed by the famous theoretical meteorologist, Dr. Edward Lorenz, approximately 55 years ago when he suggested that the flap of a butterfly's wings might ultimately cause a tornado in reference to the slight changes in some of the data being entered as initial conditions in a numerical weather prediction model resulted in drastically different output results. EJH] [NOAA Climate.gov News]
• Reason for more smog in rural West may be found -- Researchers from NOAA's Geophysical Fluid Dynamics Laboratory and Princeton University recently found that increased air pollution generated in Asia is responsible for the increase in smog across the Western United States, especially during spring. Nitrogen oxide emissions in Asia, which have tripled since 1990, appear to be blamed for increased low-level ozone levels and smog across the Western States over the last 25 years. On the other hand, smog levels have decreased in the Eastern US, except for times of heat waves. [NOAA News]

CLIMATE AND HUMAN HEALTH

• Concurrent heat waves and air pollution events combine to exacerbate negative health effects of each -- Researchers at the University of California Irvine report that the combination of heat waves and air pollution events that run concurrently over several days greatly compounds the negative effects of each event and can pose a major risk to human health. The researchers based their findings upon the analysis of records of surface ozone and the amounts of fine particulate matter for pollution events and observed maximum daily temperatures between April and September across the eastern United States and Canada over 15 years (1999-2013). They found that slow-moving high-pressure systems accumulate pollutants and heat during the summer months, allowing poor-quality hot air to stagnate in a given location for an extended period of time. [University of California Irvine News]

CLIMATE AND SOCIETY

• Nuisance flooding from smaller storms and climate change could be more costly over time than extreme, infrequent events -- Researchers at the University of California Irvine claim that rising sea levels associated with changing climate will cause relatively small storms to cause increasingly more frequent nuisance flooding in the future. They argue that a cumulative effect of these smaller events could exceed the catastrophic and more infrequent extreme events such as Hurricane Katrina or Superstorm Sandy. The researchers based their conclusions on their analysis of the likelihood of exceedances above mean higher high water and the corresponding property value exposure for minor, major, and extreme coastal floods in 11 coastal cities in the US. They proposed a Cumulative Hazard Index (CHI) that would serve as a tool for framing the future cumulative impact of low cost incidents relative to infrequent extreme events. [University of California Irvine News]
• Earthweek -- Diary of the Planet [earthweek.com]

Concept of the Week: Tropospheric westerly winds, north and south

The theoretical existence of upper tropospheric jet stream winds were not confirmed until being encountered by World War II bomber pilots when heading west into strong headwinds at altitudes of approximately 30,000 feet (10,000 m). Wind speeds sometimes exceeded 170 mph causing their relatively slow, heavily laden aircraft to almost stand still. Subsequently, westerly jet stream winds were found to encircle the planet in midlatitudes of both hemispheres above regions of strong temperature contrasts.

The explanation for these winds involves atmospheric mass distributions and forces on a rotating planet. Air in tropical latitudes is warmed, rises and then flows poleward, both north and south. On a rotating planet, moving air is deflected by the Coriolis effect, to the right in the Northern Hemisphere (and left in the Southern). The greater the temperature differences between warm lower and cold higher latitudes, the stronger the air motions and the faster the jet streams. The vertical temperature patterns result in the highest wind speeds near the top of the troposphere.

So Northern Hemisphere air headed northward, deflected to the right ends up headed east, a "westerly wind." In the Southern Hemisphere, southward moving air, deflected left will also go east, as a westerly wind. These "rivers" of strong upper-level winds steer surface weather systems as they move generally eastward across midlatitudes. They also provide boosts for jet aircraft headed eastward with them, but need to be avoided for going west! Of course, the full story is complex as land (especially mountains) and water surfaces interact with the heating of the air and eddies form in the turbulent flows, so jet streams wander. And with them go the storms and the weather patterns that form our short-term climate.

Concept of the Week: Questions

(Place your responses on the Chapter Progress Response Form provided in the Study Guide.)

1. The Northern Hemisphere jet stream winds would be directed such that cold air is [(to the left),(to the right),(directly ahead)] of their forward motion.
2. In the Southern Hemisphere, the jet stream winds to be directed generally toward the [(south), (east), (west)].

Historical Events:

• 6 March 1900...A chinook wind blowing down the slopes of the Rockies through Havre, MT raised the temperature 31 degrees in just three minutes. (The Weather Channel)
• 6 March 1954...Florida received its greatest modern-day snowfall of record, with 4.0 inches at the Milton Experimental Station. Pensacola, FL equaled their 24-hour record with 2.1 inches of snow. (The Weather Channel)
• 6 March 1962...Forty-two inches of snow fell at Big Meadows, located in the mountains of Virginia, for a state record as part of the Great Atlantic Coast Storm of 1962. (Intellicast)
• 6 March 1971...The temperature at Palteau Rosa, Italy fell to 30.2 degrees below zero Fahrenheit, Italy's lowest temperature on record. (The Weather Doctor)
• 6 March 1977...The highest recorded wind gust in the United Kingdom was 144 mph at the Cairngorm Weather Station in Scotland. (National Weather Service files)
• 7 March 1932...A severe coastal storm set barometric pressure records from Virginia to New England. Block Island, RI reported a barometric pressure reading of 955.0 millibars (28.20 inches of mercury). (David Ludlum)
• 7 March 1996...6.5 inches of snow fell at Boston, MA on this date to bring its seasonal total to 96.4 inches -- the city's snowiest winter in 105 years of record keeping. The old record was 96.3 inches set in the 1993-94 winter season. Now all major cities along this East Coast had broken their seasonal snowfall records in the 1995-96 winter season. (Intellicast)
• 7 March 2000...The temperature at Duluth, MN reached 70 degrees, which was the earliest that a 70-degree reading was reported in Duluth; the previous earliest date was 22 March 1945 when the temperature reached 72 degrees. (Accord's Weather Guide Calendar)
• 7 March 1999...Moncton, New Brunswick, Canada's snowiest major city set a new record for a one-day snowfall of 45.7 inches, but prior to that date the winter's total had been a meager (for the city) 46 inches of snow. (The Weather Doctor)
• 8 March 1971...A snowstorm dropped 10 to 20 inches of new snow across Vermont to raise snow depths to record levels. A snow cover of 116 inches was measured on the ground on top of Mount Mansfield, the second highest snow depth ever recorded on the mountain up to the time. The town of Orange measured 88 inches on the ground for a new state low-elevation snow depth record. (Intellicast)
• 8 March 1992...In the first 8 days of March, Las Vegas, NV recorded 1.87 inches of rain, setting a new monthly record for rainfall in March. The previous record was 1.83 inches set in 1973. (Intellicast)
• 8 March 1994...A major snowstorm buried sections of Oklahoma, Missouri, and Arkansas. Ozark Beach, MO recorded 19 inches of snow, while Harrison, AR checked in with 18 inches. Tulsa, OK had 12.9 of snow, for its greatest single storm snowfall ever. (Intellicast)
• 8 March 1996...Elkins, WV received 2.1 inches of snow on this day to bring its seasonal snowfall to 125.8 inches -- its snowiest winter on record. (Intellicast)
• 9 March 1911...Aibonito, Puerto Rico had temperature of 40 degrees Fahrenheit, the lowest temperature recorded on that island. (The Weather Doctor)
• 9 March 1943...The temperature at Lac Frontiere, ME fell to 40 degrees below zero, the lowest reading ever in March in New England. (Intellicast)
• 9 March 1956...A whopping 367 inches of snow was measured on the ground at the Rainier Paradise Ranger Station in Washington. The snow depth was a state record and the second highest total of record for the continental U.S. (The Weather Channel)
• 10 March 1912...The barometric pressure reached 990.9 millibars (29.26 inches) at Los Angeles, CA, and 997.7 millibars (29.46 inches) at San Diego, CA, setting all-time records for those two locations. (David Ludlum)
• 10 March 1922...Dodge City, KS reported an all-time record 24-hour total of 17.5 inches of snow. (The Weather Channel)
• 10-11 March 1972, The temperature at Chicago, IL rose from 15 degrees on the 10th to 73 degrees on the 11th. The 58-Fahrenheit degree temperature rise tied the city's largest day-to-day rise on record. The city experienced a similar jump in temperature in February 1887. (The Weather Doctor)
• 11 March 1911...Tamarack, CA reported 451 inches of snow on the ground, a record for the U.S. (David Ludlum)
• 11 March 1948...Record cold followed in the wake of a Kansas blizzard. Lows of 25 degrees below zero at Oberlin, Healy, and Quinter established a state record for the month of March. Lows of 15 degrees below zero at Dodge City, 11 degrees below zero at Concordia, and 3 degrees below zero at Wichita were records for March at these locations. The low of 3 degrees below zero at Kansas City, MO was their latest subzero reading of record. (The Weather Channel) (Intellicast)
• 11 March 2006...The record run for dry days in Phoenix, AZ finally ended at 143 at 12:07 AM MST. The last measured rain in the city fell on 18 October 2005. The last time the region had significant precipitation was 2 August when 0.59 inch (15 mm) fell. Not only did the rain break the dry spell, the 1.40-inch total was a record amount for the date: The previous consecutive dry-day mark, set in 1998-99, was 101 days. (The Weather Doctor)
• 12-13 March 1907...A storm produced a record 5.22 inches of rain in 24 hours at Cincinnati, OH. (The Weather Channel)
• 12 March 1923...The record low air pressure of 971.9 millibars (28.70 inches) for Chicago, IL was set during a storm that produced heavy snow, a thick glaze, gales, and much rain that caused $800,000 damage. (Intellicast)

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Prepared by Edward J. Hopkins, Ph.D., email hopkins@aos.wisc.edu
© Copyright, 2017, The American Meteorological Society.