WEEK SIX: 2-6 March 2015

ITEMS OF INTEREST

• High-quality maps of March temperature and precipitation normals across US available -- The PRISM Climate Group at Oregon State University's website has prepared high-resolution maps depicting the normal maximum, minimum and precipitation totals for March and other months across the 48 coterminous United States for the current 1981-2010 climate normals interval. These maps, with a 800-meter resolution, were produced using the PRISM (Parameter-elevation Regressions on Independent Slopes Model) climate mapping system.
• March weather calendar for a city near you -- The Midwestern Regional Climate Center maintains an interactive website that permits the public to produce a ready to print weather calendar for any given month of the year, such as March, at any of approximately 270 weather stations around the nation. (These stations are NOAA's ThreadEx stations.) The entries for each day of the month includes: Normal maximum temperature, normal minimum temperature, normal daily heating and cooling degree days, normal daily precipitation, record maximum temperature, record minimum temperature, and record daily precipitation; the current normals for 1981-2010.
• 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.
• National Severe Weather Awareness Week -- The American Red Cross will be observing "National Severe Weather Awareness Week" that runs from Sunday 1 March through Saturday 7 March 2015. The Red Cross encourages people across the country to get ready for severe weather. NOAA's National Weather Service also has information on its NOAA "Weather-Ready Nation" website.

CURRENT CLIMATE MONITORING

• Ice covered lakes and bays across Northeast seen from space -- A portfolio of recent natural color satellite images focuses on the widespread ice cover on the waters of the eastern Great Lakes and the various bays and harbors along the Middle Atlantic and New England coasts, which developed because of the exceptionally cold month of February 2015. The images were made from the the Operational Land Imager (OLI) on NASA's Landsat 8 and the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite. [NASA Earth Observatory]
• First global rainfall and snowfall map from new satellite is released -- During the last week NASA released the first global map of rainfall and snowfall obtained from data collected by the agency's new Global Precipitation Measurement (GPM) Core Observatory on the first anniversary of the spacecraft's launch. This first global rainfall and snowfall map from the GPM Core Observatory along with 12 other satellites is a nearly two-minute video covering approximately 87 percent of the Earth's surface area over a time span running from April to September 2014 using an update-interval of every half hour. This video was produced by NASA's Integrated Multi-satellite Retrievals for GPM (IMERG) that assembled the data from GPM and the additional NASA, NOAA and Defense Department satellites from the US and those from Japan, India, France and EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites). [NASA Goddard Space Flight Center News]
• Vegetation health pattern across California Golden State becomes varied during this winter season -- Comparison of maps depicting the Enhanced Vegetation Index (EVI) for California in early January 2014 with those in January 2015 reveal an increased complexity to the vegetation pattern across the Golden State due to the record dry year across most of the state that was only partially ameliorated by some beneficial precipitation that fell across some sections in December 2014. The EVI is a satellite data product obtained from the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the NASA/NOAA Suomi NPP satellite that assesses the health of the vegetation cover. [NASA Earth Observatory]
• New land cover database for Alaska shows decade of change in Arctic -- The US Geological Survey (USGS) recently released the latest edition of the National Land Cover Dataset for Alaska that shows changes in the land cover across the 49th State over the last decade. This dataset has been produced from data collected from sensors onboard the NASA/USGS Landsat satellites. Large changes in land cover across Alaska between 2001 and 2011 have involved conversion of forests to shrub and grasslands due to wild land fire and the losses in the perennial ice and snow and in the wetlands. [USGS Newsroom]
• Recent two-year spike in sea level found along the Atlantic coast -- Scientists from the University of Arizona and NOAA have discovered an approximately four inch jump in the sea level of the western North Atlantic Ocean from New York to Newfoundland between 2009 and 2010 because of changes in the Atlantic Meridional Overturning Circulation and also a change in part of the North Atlantic Oscillation. The spike in sea level was discovered from analysis of monthly tide-gauge records collected by 40 tide gauges along the Atlantic coast since the early 20th century. The team used computer climate models From NOAA's Geophysical Fluid Dynamics Laboratory to project a higher frequency in such spikes in the future, which would be made worse by rising sea levels due to ocean warming and melting land ice. [NOAA Oceanic and Atmospheric Research News]
• Exploring the differences in the global temperature records -- NASA's Earth Observatory describes the reasons why differences arise in the time series of global temperatures produced by NOAA's National Climatic Data Center, NASA's Goddard Institute for Space Studies, the United Kingdom's Met Office Hadley Center/Climatic Research Unit and the Japanese Meteorological Agency. Although the long term trends in these four time series are generally close over the last 134 years, the subtle differences appear magnified when comparisons are made of the rankings of highest yearly global temperatures, especially over the last decade. The differences between the global temperature records of these four institutions arise from how each handles the spatial averaging of temperatures over data sparse areas over the oceans and the polar caps. [NASA Global Climate Change News]

CLIMATE FORECASTS

• Canadian national seasonal outlook issued -- Forecasters with Environment Canada issued their outlooks for temperature and precipitation across Canada for meteorological spring, of the three months of March through May 2015. Their temperature outlook indicates that sections of southeastern and eastern Canada extending from the Great Lakes northeastward to Newfoundland and Labrador could experience below normal (1981-2010) temperatures for these three months. A small area of the Prairie Provinces of Alberta and Saskatchewan along the US-Canadian border could also see below average spring temperatures. On the other hand, sections of coastal British Columbia, the Yukon and Northwest Territories and the western Canadian Archipelago could have above average spring temperatures. Elsewhere, near normal temperatures were to be expected for the next three months.
  The Canadian precipitation outlook for Spring 2015 indicates that most of Canada should experience near average precipitation. Scattered areas of southwestern British Columbia, northern sections of Manitoba and Ontario and eastern Canada centered on Newfoundland and Labrador could experience below average precipitation. Conversely, above normal spring precipitation was projected widely scattered areas of the southern Prairie Provinces, southeastern Ontario and northwestern Canada that included the Yukon and Northwest Territories.
  [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.]

CLIMATE FORCING

• A "false pause" in global warming attribute to interactions of ocean oscillations -- Researchers from Penn State University claim that the recent "false pause" or slowdown in climate warming appears to be due in part to the natural oscillations in the climate system, with some of these rhythmic variations being driven by substantial natural, internal climate variability in the North Atlantic and North Pacific oceans that are on time scales of decades. The Atlantic Multi-Decadal Oscillation (AMO) tends to oscillate with a periodicity of between 50 and 70 years, while the Pacific Decadal Oscillation (PDO) varies over a broader range of time scales [Penn State University News]
• Persistent upper air flow pattern brings record snows to New England and summer-like warmth to the West -- A feature on the NOAA Climate.gov website describes the reasons for the series of winter storms that brought record snowfall across New England while unseasonably warm conditions prevailed across the West. A high amplitude wavelike flow pattern in the winds in the mid and upper troposphere persisted through most of February. This pattern featured a northward diversion of these upper level westerlies across the North Pacific and western North America, while the winds dipped well to the south across the eastern half of the nation. A map of the differences between the flow pattern from late January through mid February 2015 and the typical flow is provided in terms of the anomalies in the height of the 500-millibar constant pressure surface at approximately 18,000-foot altitude shows a warm height ridge across the West and a cold height trough in the East. Another map shows warmer that average sea surface temperatures of the western North Atlantic off the East Coast, which helped build a large temperature contrast across the Northeast that helped winter storm development. [NOAA Climate.gov News]
• Direct observation made of carbon dioxide's increasing greenhouse effect at Earth's surface -- Researchers at the US Department of Energy's Lawrence Berkeley National Laboratory and their colleagues from other research institutions have made the first direct observation of the increasing contribution that atmospheric carbon dioxide makes on the Earth's surface over an eleven-year span at sites in Oklahoma and Alaska. These observations using spectroscopic instruments provide a link between increasing carbon dioxide levels from human activity with an upward trend in the surface radiative forcing at these two locations, which represents a measure of the amount that the surface energy budge is perturbed by atmospheric changes. [Lawrence Berkeley National Laboratory News Center]

CLIMATE AND THE BIOSPHERE

• Satellite tracks the amount of Saharan dust feeding Amazon plants -- Scientists at NASA's Goddard Space Flight Center have used data obtained from the lidar instrument on NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, (CALIPSO) satellite from 2007 though 2013 to assess the quantity of phosphorus transported in the dust from the Sahara to the Amazon by winds. The phosphorous in the dust from the Sahara in Africa that is carried across the Atlantic helps fertilize the plants in the Amazon rain forests in South America. The team estimated that the phosphorus reaching the Amazon is approximately 22,000 tons per year. [NASA Goddard Space Flight Center]

CLIMATE AND SOCIETY

• Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

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:

• 2 March 1927...Raleigh, NC was buried under 17.8 inches of snow in 24 hours, a record for that location. Nashville, NC received 31 inches of snow. The average snow depth in the state of Carolina was fourteen inches. (The Weather Channel)
• 2 March 1947...The one-day record snowfall of 16 inches of snow buried Canada's capital city of Ottawa, Ontario. The storm left 28.7 inches of snow covering the Ottawa region. (The Weather Doctor)
• 2 March 1996...Another East Coast snowstorm deposited 4.6 inches of snow at Central Park in New York City to bring its seasonal snowfall total to 66.3 inches, breaking the old season snowfall record of 63.2 inches set in 1947-48. (Intellicast)
• 3 March 1896...The temperature in downtown San Francisco, CA fell to 33 degrees, which was the lowest ever for the city in March. (Intellicast)
• 3 March 1971...An extremely intense coastal storm blasted the northeastern US on this day and continued into the 4th. The barometric pressure dropped to 960 millibars (28.36 inches) at Worcester, MA for the lowest pressure ever recorded at the location. The same record was set at Concord, NH with a reading of 963 millibars (28.44 inches). Wind gusts 70 to 100 mph lashed eastern New England with major wind damage occurring. Tides ran 4 to 5 feet above normal resulting in extensive coastal damage and beach erosion. (Intellicast)
• 3 March 1994...A major coastal storm was in progress over the mid-Atlantic and the Northeast. The 8.7 inches of snow at Allentown, PA raised its seasonal snowfall to 69.2 inches for its snowiest winter ever. Boston's 8 inches pushed its seasonal snow to 89.5 inches for its snowiest winter as well. (Intellicast)
• 3 March 2003...The day's low temperature of 30 degrees below zero at Marquette, MI was the lowest temperature ever recorded in March in the city. (The Weather Doctor)
• 4 March 1953...Snow was reported on the island of Oahu in Hawaii. (The Weather Channel)
• 4-5 March 1899...Tropical Cyclone Mahina (the Bathurst Bay Hurricane) crossed Australia's Great Barrier Reef and generated produced the highest storm surge ever recorded: 13 m (42.6 ft) surge in Bathurst Bay. The Australian pearling fleet was destroyed, over 100 shipwrecks reported and 307 people killed. Minimum central pressure barometric pressure fell to an unofficial reading of estimated at 914 millibars (26.90 inches of mercury). (Accord's Weather Calendar) (The Weather Doctor)
• 5 March 1960...The greatest March snowstorm of record in eastern Massachusetts began to abate. The storm produced record 24-hour snowfall totals of 27.2 inches at Blue Hill Observatory, 17.7 inches at Worcester, and 16.6 inches at Boston. (The Weather Channel)
• 5 March 2000...The Twin Cities of Minneapolis and St. Paul, MN established a new record for the fewest number of days between 70-degree Fahrenheit temperature reading from the last date in the autumn to the first date in the spring, with only 113 days passed. The previous record was 131 days, while the average has been 175 days. (The Weather Doctor)
• 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)
• 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)

Return to DataStreme ECS website

Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2015, The American Meteorological Society.