WEEKLY CLIMATE NEWS

30 October-3 November 2017

ITEMS OF INTEREST

A summary of the nation's October climate -- NOAA's National Centers for Environmental Information has posted a summary of typical October weather across the nation, providing narratives and analyzed maps of monthly temperature and precipitation. Extreme monthly temperatures and precipitation totals are noted. A tabulation was made of the daily normal (1981-2010) maximum, minimum and average temperatures for Halloween (31 October) using 10 locations with Halloween-themed names. A discussion of the occurrence of October hurricanes and tornadoes is also provided. [NOAA NCEI News]
High-quality maps of November 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 November 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.
November 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 November, 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.
Time change does not affect climate records -- Daylight Saving Time ends this coming Sunday morning (5 November) across 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 (12 March 2017) and end on the first Sunday in November (5 November 2017). Most of Canada also observes changes to Daylight Saving Time at the same time [National Research Council Canada]. 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. Next spring, Daylight Saving Time will start on Sunday morning, 11 March 2018.
What does this time change mean to you (other than earlier 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 climate record keeping. The daily high and low temperatures, along with the 24-hour precipitation taken by essentially all stations across the nation are based upon local Standard time, not Daylight time. Therefore, the daily entries in the Preliminary Local Climate Data (CF6) for any of the more than 200 cities around the nation will remain on Standard time throughout the year. The daily climate data collected at those automatic weather stations operated by the National Weather Service and the Federal Aviation Administration, together with all the cooperative weather observing stations around the nation are always made according to local standard time. NOTE: You may check the correct current official time at http://www.time.gov/.
Reconstructing past climates -- Scientists from many disciplines have developed a variety of methods that use proxy indicators such as tree rings, ice cores and ocean cores to reconstruct past climates, some extending back thousands of years. For more details on paleoclimatology, or the study of past climates, and available data sets, please read this week's Supplemental Information...In Greater Depth.

CURRENT CLIMATE STATUS

Satellites detect an unusually long "atmospheric river" across North Pacific -- Two composite natural-color images obtained from data collected in mid-October by the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the NASA/NOAA Suomi NPP satellite shows an unusually long band of clouds stretching for approximately 5000 miles across the North Pacific Ocean from near the Japanese islands eastward to Washington on the western coast of North America. Called an atmospheric river, this relatively narrow band of clouds, along with abundant moisture and storm systems, was being carried along by upper tropospheric winds. A researcher associated with NASA's Jet Propulsion Laboratory and the University of California, Los Angeles noted that this recent atmospheric river was two to three times longer than the typical atmospheric river. [NASA Earth Observatory]
Satellite catches rapid breakup of a new iceberg -- A natural-color image obtained from the Operational Land Imager (OLI) on NASA's Landsat 8 satellite last week shows the breakup of the new iceberg called B-44 that had formed when it calved off Antarctica's Pine Island Glacier during the last week of September. [NASA Earth Observatory]
Viewing the end of an iceberg lifecycle from a satellite -- An image obtained from the MODIS sensor on NASA's Aqua satellite approximately ten days ago shows four icebergs floating in the Southern Ocean off Antarctica. These four icebergs were of varying sizes and ages. One of the icebergs was a remnant of an iceberg that had calved from the Ross Ice Shelf in 1987, while another iceberg had been formed from a collision of an iceberg with the floating tongue of the Mertz Glacier in 2010. [NASA Earth Observatory]
Reflecting on the battering that Ireland received from former Hurricane Ophelia -- A meteorologist with NOAA's Climate Prediction Center wrote an article for the Event Tracker feature of the ClimateWatch Magazine that provides an analysis of how Hurricane Ophelia and its post-tropical low recently battered Ireland with winds to at least 78 mph at Cork and torrential rains. Over 300,000 residents of Ireland lost power. Unusually warm North Atlantic waters contributed to the strength of Hurricane Ophelia, which had reached a major category 3 status on the Saffir-Simpson Scale earlier in its life. and brought heavy rains and high winds to portions of Ireland. The long-term frequency of the occurrence of a tropical cyclone in Ireland was also addressed, along with the possibility that such an occurrence could be associated with a changing climate. [NOAA Climate.gov News]

CURRENT CLIMATE MONITORING

GRACE Mission comes to an end -- Late last week NASA reported that scientific operations of the 15-year old U.S./German GRACE (Gravity Recovery and Climate Experiment) satellite mission were being terminated as the battery onboard one of the twin GRACE satellites had limited power and this satellite was being decommissioned. This mission, living 10 years beyond its planned five-year lifetime, provided scientists with insights into the interactions of planet Earth's ocean, atmosphere and geosphere components by tracking the continuous movement of liquid water, ice. [NASA Press Release]

CLIMATE FORCING

Orbiting satellites provide unique views of recent intense solar activity -- NASA scientists have assembled an assortment of images of the Sun taken during the period of intense solar activity (6-10 September 2017) that included solar flares and powerful coronal mass ejections. These images were obtained from instruments on the nation's fleet of orbiting satellites include NOAA's GOES (Geostationary Environmental Operational Satellites)-16; NASA's SDO (Solar Dynamics Observatory); the Japanese/NASA JAXA/NASA's Hinode mission, the European Space Agency/NASA SOHO (Solar and Heliospheric Observatory); NASA's SORCE (Solar Radiation and Climate Experiment); the STEREO (Solar TErrestrial RElations Observatory) and NASA's MAVEN (Mars Atmosphere and Volatile Evolution). [NASA Goddard Space Flight Center Feature]

CLIMATE AND THE BIOSPHERE

First frosts of the year are coming later -- In a study conducted by an atmospheric scientist at NOAA's National Centers for Environmental Information, the timing of the first freeze that effectively ends the growing season has been getting later in the year over the last ten years. Using temperature data from approximately 700 weather stations with long-term records, this scientist found that the average first freeze during the last ten years (2007-2016) was a week later than the average from 1971-1980. While the first occurrence of a day with 32-degree Fahrenheit or lower temperature is driven by the weather, the long-term trends toward later frost dates appear to be associated with a changing climate marked by higher temperatures. Later frost dates have an impact on plants because of longer growing seasons and shorter freeze seasons, especially if the dates of the occurrence of the last 32-degree temperature trends earlier in spring. [Los Angeles Times]
Forests appear to mitigate severe heat waves -- A climate scientist at NOAA's Geophysical Fluid Dynamics Laboratory and colleagues from NASA Goddard Space Flight Center and three research universities in the Middle Atlantic States recently reported on their computer modeling efforts involving the role that an extensive mature forest cover has on mitigating the impact of severe heat waves. They found that the conversion of native forests to cropland has resulted in a two- to four-fold increase in the frequency of hot and dry summers in the mid-latitudes of the United States and Europe. In addition, they compared recently available global land cover observations of temperature and humidity from satellites over 12 years with their model results. [NOAA Office of Oceanic & Atmospheric Research News]

CLIMATE AND SOCIETY

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

Concept of the Week: Extending the Historical North American Drought Record

Through history, drought has been a major concern for many people as the lack of adequate water can adversely affect agriculture, and in the extreme case, the availability of potable (drinkable) water. The Case in Point for Chapter 9 describes the migration of ancient peoples across the semiarid Southwest due to what may have been major drought conditions. During the last century, the "Dust Bowl" era drought in the 1930s created many problems in this country. The effects of this seven-year long drought were made worse by poor agricultural techniques and land management. The effect of the drought on the nation was also exacerbated by the coincident Great Depression. Drought remains a problem today across Texas and the West Coast as we can see from inspection of the current weekly US National Drought Monitor produced by the National Drought Mitigation Center.

How do the current drought events compare with earlier droughts? A time series of computed Palmer Drought Severity Index (PDSI) values began in 1895 when a sufficiently dense climate network was established. During the 20th century, several episodes of drought have had a major national impact. The exceptional drought that developed in the early 1930s extended across much of the nation resulting in the "Dust Bowl" era. The PDSI time series shows that the 1930s drought was the worst in the last century, with nearly 80 percent of the nation experiencing moderate to extreme drought in 1934. During the 1950s, the southern Plains and the Southwest also experienced a major drought, when 50 to 60 percent of the nation was under drought conditions.

What about farther back in history? Sophisticated tree-ring analysis techniques allow researchers to extend the drought record across a large section of North America farther into the past. In 1998, Edward R. Cook at Columbia University's Lamont-Doherty Earth Observatory along with colleagues at Arizona and Arkansas reconstructed past drought conditions across the nation based upon annual tree-ring data obtained from a network of 388 climatically sensitive tree-ring sites. From these data, time series of annual summertime (June-August) PDSI values were determined back to 1700 at 155 grid points across the nation. These gridded tree-ring chronologies were calibrated with PDSI chronologies generated by instrumental records at selected Historical Climate Network stations commencing in the late 19th century. The researchers found that the 1930s drought was the most severe drought to hit the nation since 1700.

By 2004, the series was expanded to 835 tree-ring sites, primarily across the West, where exactly dated annual tree-ring chronologies were obtained. The new grid covered most of North America with a latitude-longitude spacing of 2.5 degrees. In addition to the 286 grid point PDSI time series, annual contour maps of PDSI were constructed that span much of the continent. This work permitted extension of the spatial and temporal coverage of the drought reconstruction not only into Canada and Mexico, but back 2000 years. From this more recent data set they produced an online "North American Drought Atlas." They found several "megadroughts" in North America were even more severe than the 1930s drought. In addition to being more severe, some droughts extended over several decades, considerably longer than those of the 20th century. One such megadrought was in the 16th century, an event that along with another megadrought into the early 17th century has been implicated by some researchers in the hardships encountered by British settlers in the Virginia area, such as the disappearance of the Roanoke Colony.

Historical Events:

30 October 1925...Nashville, TN was blanketed with an inch of snow, their earliest measurable snow of record. (The Weather Channel)
31 October 1987...Yakima, WA reported measurable rainfall for the first time since 18 July. The 103-day long dry spell was their longest of record. (The National Weather Summary) (Storm Data)
31 October 1991...A severe winter storm dubbed the "Great Halloween Mega Storm" struck the upper Midwest. Minnesota bore the brunt of the storm. By the time the storm finally ended on 2 November, Duluth received 37 inches of snow and Minneapolis 28 inches, which were new all time records for single storm totals. These two cities received nearly half their normal seasonal snows in this one storm. In Wisconsin, 35 inches of snow was reported at Superior and 30 inches at Iron River. (Intellicast)
31 October 1993...Corpus Christi, TX dropped to 28 degrees to set the October (and November) record. Brownsville dropped to a monthly record 35 degrees. (Intellicast)
2 November 1946...A heavy wet snow began to cover the Southern Rockies. Up to three feet of snow blanketed the mountains of New Mexico, and a three-day snowstorm began at Denver, CO. By the time it ended, this storm had dropped 31 inches, making it the second greatest snowfall ever in city history and causing roofs to collapse. (David Ludlum)
2 November 1961...The temperature at Atlanta, GA reached 84 degrees to establish a record for November. (The Weather Channel)
2 November 1966...A storm brought 18 inches of snow to Celia, KY in 24 hours. It tied the state 24-hour snowfall record first established at Bowling Green. (The Weather Channel)
2 November 1988...A very intense low pressure system brought heavy rain, snow, and high winds, to parts of the northeastern U.S. Portland, ME established a record for November with 4.52 inches of rain in 24 hours, and winds along the coast of Maine gusted to 74 mph at Southwest Harbor. (The National Weather Summary) (Storm Data)
3 November 1890...The temperature at Los Angeles, CA reached 96 degrees, a November record for 76 years. (David Ludlum)
3 November 1927...The "Great Vermont Flood" began as a two-day rain of up to 9 inches put rivers in western New England over their banks. Somerset, VT was deluged with 8.77 inches of rain to establish a 24-hour record for the state. (3^rd-4^th) (The Weather Channel) (Intellicast)
3 November 1989...Cold weather prevailed in the central U.S. The low of 7 above zero at Marquette, MI was their lowest reading of record for so early in the season. (The National Weather Summary)
4 November 1983...The temperature at Billings, MT soared to 77 degrees, a new record for the data and month. (Intellicast)
4-5 November 1966...The River Arno surged above flood stage and caused irreparable damage to much of the architectural and art treasure of Florence, Italy. Millions of historical library volumes were either damaged or destroyed. More than 15,000 vehicles were also destroyed. Roughly two-thirds of Florence was flooded, 113 people died and 30,000 were made homeless by the flooding on both the Arno and Po rivers. (Accord Weather Calendar) (Wikipedia)
5 November 1977...A slow moving storm produced five- to nine-inch rains across northern Georgia causing the Toccoa Dam to burst. As the earthen dam collapsed, the waters rushed through the Toccoa Falls Bible College killing three persons in the dorms. Thirty-eight persons perished at a trailer park along the stream. Eighteen bridges were washed out in Madison County. (David Ludlum)
5 November 1987...Heavy rains in California's Death Valley National Park washed out many park roads. As much as 1.20 in. of rain fell at Scotty's Castle, compared with the annual rainfall average of 2.28 in. Up to 8000 people attending a recreational encampment were stranded. (Accord Weather Calendar)
5 November 1991...Elkins, WV dropped to 8 degrees, the coldest so early in the season. Pittsburgh, PA dropped to 11 degrees also the coldest so early. Jackson, KY fell to 17 degrees, a daily record. (Intellicast)

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