WEEKLY CLIMATE NEWS

18-22 September 2017

ITEMS OF INTEREST

Worldwide GLOBE at Night 2017 Campaign is underway -- The eighth in the series of GLOBE at Night citizen-science campaigns for 2017 will continue through Thursday, 21 September. GLOBE at Night is a worldwide, hands-on science and education program designed to encourage citizen-scientists worldwide to record the brightness of their night sky by matching the appearance of a constellation (Cygnus in the Northern Hemisphere and Sagittarius in the Southern Hemisphere) with the seven magnitude/star charts of progressively fainter stars. Activity guides are also available. The GLOBE at night program is intended to raise public awareness of the impact of light pollution. The next series in the 2017 campaign is scheduled for 11-20 October 2017. [GLOBE at Night]
The Autumnal Equinox --The Autumnal Equinox will occur early this coming Friday afternoon (officially at 2002Z on 22 September 2017 or 4:02 PM EDT or 3:02 PM CDT, etc.). At that time the noontime sun will appear directly above the equator, representing one of the two times during the year for such an occurrence, with the other being at the vernal equinox in March. The term "equinox" arises from the fact that this time of year represents "equal night" and equal day essentially everywhere. Within the subsequent several days, the length of daylight will become noticeably shorter. This decrease in daylight will continue for another three months to the winter solstice during the morning of Thursday, 21 December 2017.
Editor's note: John White, a meteorologist from North Carolina involved with the AMS Education program, reported that the geosynchronous (or geostationary) satellites make an "satellite eclipse" of the sun near the spring and autumnal equinoxes because of their equatorial orbit, such that these satellites pass through the earth's shadow and the satellite is powered down when the solar array does not receive sufficient sunlight. [For more information, consult NWS Southern Region GOES Satellite FAQ] EJH.
If you check the sunrise and sunset times in your local newspaper or from the climate page at your local National Weather Service Office, you would probably find that early next week the length of time when the Sun is above the local horizon would be precisely 12 hours at most locations. By the end of next week, the length of night will exceed that of the length of daylight. The effects of atmospheric refraction (bending of light rays by the varying density of the atmosphere) along with a relatively large diameter of the sun contribute to several additional minutes that the Sun appears above the horizon at sunrise and sunset.
September is National Preparedness Month -- The month of September has been declared National Preparedness Month (NPM), which aims to educate and empower Americans to prepare for and respond to all types of emergencies, including natural disasters. NPM is managed and sponsored by the Federal Emergency Management Administration's (FEMA) Ready Campaign in conjunction with the Ad Council, A toolkit of marketing materials is provided to help promote the month and represents the lead on this campaign that was originally launched in 2004. The overarching theme for 2017 NPM is "Disasters Don’t Plan Ahead. You Can.," with an emphasis on preparedness for youth, older adults, and people with disabilities and others with access and functional needs.
Week 3 of the 2017 NPM (17-23 September) the theme is "Practice and Build Out Your Plans."
[FEMA's Ready.gov]
Weather station in Alps celebrates 200 years of continuous observations -- The weather observation station at Grand-St-Bernard, located at an elevation of 2473 meters in the Swiss Alps near the border with Italy, celebrated 200 years of uninterrupted weather observations last Friday with a ceremony attended by officials from the World Meteorological Organization (WMO) and MeteoSwiss . The Grand-St-Bernard weather station, which is now designated as a Centennial Observing Station, was managed by monks for many of the 200 years, but is now operated by MeteoSwiss, Switzerland's Federal Office of Meteorology and Climatology. [World Meteorological Organization News]
Fall coloration -- By mid-September, deciduous trees begin to turn color across the nation, starting first across the higher elevations of New England and the Rocky Mountains, followed quickly across sections of the upper Midwest. During autumn, the peak in fall color progresses southward and toward lower elevations. Some locales hold events in an effort to welcome tourists who come as "leaf peepers." The Department of Agriculture's U.S. Forest Service maintains a Fall Colors Web page containing fall foliage status updates for National Forests across the continental United States. Additional information is also available through the tourism bureaus of the various states; links to some of these state sites are available from this Forest Service web page.
[Editor's Note: An interesting explanation of fall coloration can be found in The Chemistry of Autumn Colors from "Science is Fun in the Lab of Shakhashiri" from a popular chemistry professor at the University of Wisconsin-Madison. EJH]
Monitoring degree-day units -- If you would like to monitor how this upcoming winter will affect the amount of energy that you will need for heating your home, please read this week's Supplemental Information...In Greater Depth. You will see how heating degree-day units are computed, as well as the corresponding cooling-degree day units. This supplemental also provides links to tabulations of the cumulative heating and cooling degree-day units that are available on a monthly basis for selected cities across the country.

CURRENT CLIMATE STATUS

US national weather and climate reviewed for August and Summer 2017 -- Based upon preliminary data, scientists at NOAA's National Centers for Environmental Information (NCEI) report that August 2017 tied August 1921 for the 53rd coolest (or 73rd warmest) August across the coterminous United States since sufficiently reliable climate records began in 1895. The nationwide August 2017 average temperature was 72.0 degrees Fahrenheit, which temperature was 0.1 Fahrenheit degrees below the 20th-century (1901-2000) average. Many of the states across the nation's midsection experienced below to much-below average statewide August temperatures. Statewide temperatures for Illinois, Iowa, Kansas, Missouri, Nebraska and Oklahoma ranked in the ten lowest on record. On the other hand, states across the western third of the contiguous US had above to much-above average temperatures, with California, Oregon and Washington experiencing their highest August temperatures in the 123-year period of record. Above average statewide temperatures were also reported in South Carolina and Florida.
The recently concluded meteorological summer of 2017 (June, July and August) was the fifteenth warmest summer since 1895, with a three-month average temperature of 72.7 degrees, which was 1.3 Fahrenheit degrees above the 20th century average. The nine states from the Rocky Mountains westward to the Pacific Coast experienced much above average summer temperatures, with California and Nevada reporting their warmest summer since 1895. Oregon had a summer average temperature that was second highest, while Utah was third highest on record. States along the Atlantic Seaboard had above average summer temperatures, with Florida reporting a statewide temperature that was twelfth highest. Conversely, states in the lower Mississippi and Ohio Valleys and the southern Plains reported statewide average summer temperatures that were below-average. The average maximum (daytime) temperature across the "Lower 48 States" for summer 2017 was 25th highest on record, while the average minimum (nighttime) temperature was the 11th highest on record. California reported record high summer maximum and minimum temperatures, while Nevada also had a record high summer minimum temperature.
The nationwide August 2017 average precipitation was 3.34 inches, which made the month the seventh wettest August in 123 years. Many of the states across the nation's midsection had above to much above average statewide precipitation totals. Texas had its wettest August on record, while Louisiana had its second highest statewide August precipitation total and Oklahoma its third highest. Conversely, states across the interior West, the Midwest and New England had below average precipitation totals. Montana reported its eleventh lowest precipitation total on record.
The nationwide summer (JJA) precipitation was 0.87 inches above the 1901-2000 average, which was makes this past summer the sixteenth wettest across the "Lower 48 States" since 1895. The northern tier of states, running from Washington eastward to Illinois had a dry summer, with Montana experiencing its second driest summer on record and Washington its seventh driest. Maine and Connecticut in New England also States across the nation's midsection reported above average precipitation, with eight states in the Mississippi Valley having statewide average precipitation totals that ranked in the top 10 on record. On the other hand, states along the Gulf Coast and from the Great Lakes to the Middle Atlantic Coast had above to much-above average precipitation. Mississippi experienced its wettest summer in 123 years, while Florida and Louisiana had their second wettest, with Texas reporting its third wettest. [NOAA/NCEI State of the Climate]
NOTE: A description is provided of the climatological rankings employed by NCEI for their monthly and seasonal maps. [NOAA/NCEI]
Deke Arndt, the Chief of the Climate Monitoring Branch at NCEI, recently posted his "Beyond the Data" blog that addresses five questions concerning the weather and climate across the nation during August 2017, focusing upon the possible records associated with Hurricane Harvey. [NOAA Climate.gov News]
August national drought report -- The National Centers for Environmental Information posted its August 2017 drought report online. Using the Palmer Drought Severity Index, approximately four percent of the coterminous United States experienced severe to extreme drought conditions at the end of August, while 14 percent of the area had severely to extremely wet conditions.
El Niño/Southern Oscillation (ENSO) Diagnostic Discussion -- NOAA's Climate Prediction Center (CPC) and the International Research Institute for Climate and Society (IRI) recently released their El Niño/Southern Oscillation (ENSO) Diagnostic Discussion that showed ENSO-neutral conditions were observed during the month of August 2017, meaning that neither an El Niño or La Niña event was underway as near- to below-average sea surface temperatures (SST) were found across the central and eastern equatorial Pacific during this past month. In addition, near-surface trade winds were stronger in the western equatorial Pacific and convection was also suppressed across this region. Most of the forecast models indicate a continuation of ENSO-neutral conditions through the Northern Hemisphere's 2017-18 winter (December-February). However, recently run models suggest the possibility for development of La Niña conditions starting as early as this fall (September-November). Consequently, forecasters at CPC have issued a La Niña watch, which indicates an increasing chance (~55-60%) of La Niña developing during the Northern Hemisphere fall and winter 2017-18. An ENSO blog written by a CPC contractor describes the ENSO-neutral conditions that continued into early September and why her colleagues at CPC decided to post a La Niña watch for the upcoming autumn and winter months. [NOAA Climate.gov News]
A detailed and more technical El Niño/Southern Oscillation Diagnostic Discussion with supporting maps and charts is available from CPC.
Forecasters with the Australian Bureau of Meteorology recently issued an updated ENSO forecast from a Southern Hemisphere perspective. They reported continuation of ENSO-neutral conditions. However, they foresee a possible cooling, which could result in a transition to La Niña conditions by the end of the calendar year of 2017, which corresponds to Southern Hemisphere summer. [Australian Government Bureau of Meteorology]

CURRENT CLIMATE MONITORING

Deep ocean observations to be expanded due to assistance from a philanthropic organization -- Earlier this month, a public-private partnership was formed between Paul G. Allen, Microsoft co-founder and founder of Paul G. Allen Philanthropies, and NOAA's Pacific Marine Environmental Laboratory that is intended to deploy a large array of new deep ocean floats, which will expand ocean observations in a key area of the western South Atlantic Ocean. These new Deep Argo buoys will probe the great ocean conveyor belt or global thermohaline circulation that drive large-scale weather and climate patterns. [NOAA Media Release]
Focus upon accomplishments of NASA's aging GRACE mission -- A feature article was recently produced that describes how the twin GRACE (Gravity Recovery and Climate Experiment) satellites, which were launched in 2002 as a collaborative effort of NASA and the German Aerospace Center, DLR, have been collecting data on the Earth's gravitational field. These twin satellite orbit Earth at an altitude of 286 miles, detecting subtle gravitational changes. This article explains how the data collected by the GRACE mission have been used to identify seasonal and other long-term climate and human-caused changes in water mass between the various hydrologic reservoirs within the Earth system. [NASA Global Climate Change News]
Following a four-day loss of contact with one of the GRACE satellites due to an age-related issue, scientists at NASA's Jet Propulsion Laboratory are making plans to make an anticipated final science collection of data between mid-October and early November from the satellite mission that was only expected to last five years after its launch in 2002. [NOAA Climate.gov News]

CLIMATE FORCING

Smoke from wildfires in western North America reaches Europe --Maps made from data collected during the first week of September by the Ozone Mapping Profiler Suite onboard the NOAA/NASA Suomi NPP satellite shows aerosols (or smoke) produced by wildfires across western sections of the United States and Canada being carried eastward across the United States and the North Atlantic Ocean, reaching western Europe. This smoke was carried by winds in the upper troposphere. A broad area of smoke across the northern Plains and the Upper Midwest could be seen on a natural-color image made from data obtained by the MODIS (Moderate Resolution Imaging Spectroradiometer) on NASA's Aqua satellite in mid-September. [NASA Earth Observatory]

CLIMATE AND THE BIOSPHERE

Earth's oldest trees in the Great Basin could be losing survival race as climate changes -- Researchers with the University of California, Davis and the US Forest Service recently reported that the tree line in the Great Basin (that includes sections of Nevada, California and Utah) has been steadily moving upslope during the last 50 years because of a changing climate. They also note that limber pine trees have been more successfully "leapfrogging" the ancient bristlecone pine trees, the Earth's oldest known trees, expanding upslope at a faster rate than the bristlecone pines, which used to predominate. [University of California Davis News]
Recovery from drought appears to take longer -- A team of scientists at 17 research institutions from around the nation recently published a study in which they found that a large fraction of the Earth's land surface is being affected by drought and that ecosystems are taking a longer time to recover from dry spells. This recovery appears to be longer in the tropics and in polar and subpolar latitudes, where the drought recovery time could exceed 24 months. Increased global temperatures associated with a changing climate appear to be a major factor in the longer recovery. The research team calculated these recovery times, defined as the length of time required for an ecosystem to revert to its pre-drought functional state, from changes in the gross primary productivity of vegetation based upon data obtained from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA's Terra satellite, ground measurements and computer models. [NASA Earth Observatory]
Caribbean islands turn brown because of Hurricane Irma -- Images of the British and US Virgin Islands in the Caribbean Sea that were obtained from the OLI on NASA's Landsat 8 satellite and the MODIS sensors on NASA''s Terra and Aqua satellite in late August prior to the passage of Hurricane Irma were compared with images gotten from these satellites in mid-September following the passage of Irma across these islands. The most noticeable change between these two sets of satellite images was the widespread browning of the landscape, in part due to widespread destruction of vegetation by the hurricane's strong winds and in part to the salt spray that coated the leaves on the plants, which desiccated the leaves. [NASA Earth Observatory]

CLIMATE AND SOCIETY

Earthweek -- Diary of the Planet [earthweek.com]

Concept of the Week: Climate and Architecture

Humans have been constructing houses and other buildings for thousands of years not only to protect themselves from the weather and other environmental factors, but also to create a comfortable indoor environment that would exhibit energy efficiency, especially in harsh climates. For centuries, natural or primitive housing reflected an adaptation to the climate of the locale and the availability of local building materials.

In order to maintain a tolerable level of comfort within a building, attention must be paid to thermal effects, ventilation, illumination and atmospheric humidity.

The indoor thermal state ultimately depends upon the building's energy budget involving incoming and outgoing radiation, latent and sensible heat loss and by interior heat sources or sinks. The indoor thermal level is mainly associated with the external energy load on the building. The external energy load on the building depends upon the latitude of the building, season of the year and time of day.

In tropical latitudes and during midday hours in summer, the sun's path across the local sky increases the solar radiation incident upon the roof and walls of the building. In polar latitudes, or during the winter or the amount of available sunlight is significantly lower, with the loss of infrared radiation causing a net cooling from the building. Changes in the color of the roof and the outer walls can affect the amount of incoming sunlight absorbed. Building orientation and the effective use of overhangs can also affect the amount of sunlight absorbed. Furthermore, the amount of insulation, often related to the thickness of the walls, reduces the conduction of heat into or out of the building. Thick adobe walls have been used effectively in the Southwest to moderate indoor temperature. These walls reduce the heat flow into the building during the daytime and in summer and out from the building at night or during winter.

The size and placement of windows also affects the energy balance. Large windows on the side of the building facing the sun's path tend to permit large amounts of sunlight to penetrate into the building. However, large windows on the side facing away from the sun can cause for heat loss due to conduction, as many types of windowpanes are not energy efficient.

Effective landscaping can reduce energy demands upon a dwelling: Deciduous trees planted on the south and west sides of the home provide cooling shade during the summer, keeping sunlight from entering the windows. These trees will lose their foliage in fall and allow the sun to shine through in winter, and warm south facing rooms. Evergreen trees or dense shrubbery on the north side can serve as a windbreak, which reduce the cold northerly winds from striking the house in winter.

Energy losses from buildings during the upcoming winter in northern latitudes can be seen readily by how quickly snow melts from roofs and by how big the icicles form. Heat losses from buildings occur with larger negative energy budgets, which are reflected also in higher heating bills during the winter season. However, the heating bills also depend upon the severity of the winter season that can be ascertained from the number of accumulated heating degree-day units. Check this week's Supplemental Information...In Greater Depth for how you can monitor the number of heating degree-day units to date in your state for this coming heating season.

Historical Events:

18 September 1991...2.4 inches of snow fell at Duluth, MN to set a new record for September. (Intellicast)
19 September 2004...The single-day rainfall record at Vancouver (British Columbia) International Airport was set 3.59 inches. The accumulation came in a month when rainfall is exceptional across the region. By mid-month, dozens of stations in British Columbia broke all-time September rainfall totals. (The Weather Doctor)
20-23 September 1942...A rainstorm deluged the Maritime Provinces. Four-day totals included 13.99 inches at Stellarton, Nova Scotia and 10.83 inches at Charlottetown, Prince Edward Island. Halifax, Nova Scotia recorded 9.40 inches of rain on the 21 September climatological day. (The Weather Doctor)
20 September 1967...Hurricane Beulah moved into South Texas, spawning a record 115 tornadoes for a hurricane. (David Ludlum) (Intellicast)
20 September 1973...Britain's greatest September daily rainfall floods Kent with 7.51 inches of rain. (The Weather Doctor)
22 September 1913...Des Moines, IA experienced their earliest freeze of record. (The Weather Channel)
22 September 1934...Edmonton, Alberta reported its greatest September snowstorm to date with 8.7 inches of snow. (The Weather Doctor).
23 September 1904...The temperature at Charlotteburg, NJ dipped to 23 degrees, the lowest reading of record for so early in the autumn for the state. (The Weather Channel)
24 September 1888...The earliest frost of record hit the southern states covering South Carolina, Georgia and northern Florida (Intellicast)
24 September 1926...The temperature at Riverside Ranger Station in Yellowstone Park dipped to nine degrees below zero, the lowest reading of record in the U.S. during September. (This record was broken by a 15 degree below zero reading at Big Piney, WY in September 1983.) Severe freezes were widespread over the northwestern U.S. causing great crop destruction. In Washington State, Spokane County experienced their earliest snow of record. Harney Branch Experiment Station in Oregon reported a temperature of 2 degrees above zero to establish a state record for the month of September. (David Ludlum) (The Weather Channel)
24-26 September 1950...A smoke pall from western Canada forest fires covered much of the eastern U.S. Daylight was reduced to nighttime darkness in parts of the Northeast. The color of the sun varied from pink to purple, blue, or lavender. Yellow to gray-tan was common. (24th-30th) On the 26th, residents of the northeastern U.S. observed a blue sun and a blue moon from the smoke. (David Ludlum) (The Weather Channel)

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