WEEKLY CLIMATE NEWS

30 July - 3 August 2018

ITEMS OF INTEREST

Mars is that bright object in the nighttime sky -- With planet Mars making its closest approach to Earth in the past 26 months on Tuesday, 31 July 2018, the Red Planet will appear to be the brightest in over two years during the nighttime hours of 27 July through 30 July. At closest approach on the 31st, Mars will only be 35.8 million miles from Earth. To view Mars, look for a bright object crossing the southern sky through most of the nighttime hours. [NASA Mars Exploration]
High-quality maps of August 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 August 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.
August 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 August, 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.
A celebration -- Wednesday, 1 August 2018, is the ancient Celtic holiday of Lammas that corresponds to one of the cross-quarter days, lying nearly halfway between the summer solstice (21 June 2018) and the autumnal equinox (23 September 2018). This holiday, also known as "loaf-mass day", originally marked the first wheat harvest of the year in the British Isles. [Editor's note: Next Tuesday morning, 7 August 2018, represents the exact halfway point between the dates of the solstice and equinox. EJH]
In the Land of the Midnight Sun -- The sun will set at Barrow, AK early Thursday morning (2:02 AM AKDT on 2 August 2018), marking the first time in 12 weeks (since 10 May 2018) that the sun has gone below the local horizon. However, the sun will remain below the horizon for 64 minutes before rising at 2:06 AM on Thursday. On each day until mid-November, the length of night will increase at Barrow. On the afternoon of 18 November 2018, the sun will set and remain below the horizon for a stretch of two months until late January 2019, when the sun will reappear above the horizon for slightly more than one hour, weather permitting.
Worldwide GLOBE at Night 2018 Campaign for August commences -- The eighth in a series of GLOBE at Night citizen-science campaigns for 2018 will commence this Thursday (2 August) and continue through Saturday, 11 August. 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 with the seven magnitude/star charts of progressively fainter stars. These constellations are Cygnus in the Northern Hemisphere and Scorpius for the Southern Hemisphere. Activity guides are also available. The GLOBE at night program is intended to raise public awareness of the impact of light pollution. The ninth series in the 2018 campaign is scheduled for 1-10 September 2018. [GLOBE at Night]

CURRENT CLIMATE MONITORING

Most of nation should have experienced its hottest day of 2018 by end of this month -- An article has been posted to the ClimateWatch Magazine noting that as of mid-July, most locations within the 48 contiguous United States should have experienced the highest temperatures of the year, if this summer was statistically "normal." The authors note that when using the current climatological normals for the 1981-2010 interval, the highest maximum temperature should have occurred sometime between mid-July and mid-August. The highest annual temperatures in Arizona and New Mexico typically occur in June, prior to the onset of the North American Monsoon, while the latest occurrence of highest temperatures would be found in September along the Pacific Coast due to the persistence of the marine layer with fog and low clouds. A map from NOAA's National Centers for Environmental Information shows the dates of warmest day of the year, based upon the 1981-2010 normals. [NOAA Climate.gov News]
"Wildfire hunters" fly through smoke to monitor western wildfires -- During the next two summers, researchers from NOAA, NASA, the National Science Foundation (NSF), other agencies and five universities, will be studying wildfires in both the laboratory and in the field. Like the NOAA "Hurricane Hunters" who fly into hurricanes to collect data, 18 scientists will make 15 to 20 smoke-observation flights between late July and August to make measurements of smoke particles and gases emitted from wildfires as part of the Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption and Nitrogen (WE-CAN). The team's primary interest is to understand what happens to the chemistry, composition, and size of the smoke particles when they are first emitted. The research aircraft, which will carry 30 different scientific instruments, will make flights from Boise, ID. [NOAA Research News]
Antarctica's lowest temperatures are explained -- Scientists from the National Snow & Ice Center and their colleagues from the University of Wisconsin-Madison, Temple University and Utrecht University in the Netherlands recently published an article that explains how some areas near the East Antarctic ice divide could have near surface air temperatures falling to below 90 degrees below zero Celsius. Using data collected from NASA and NOAA satellites during the winters of 2004-2016, the researchers had found surface snow temperatures had fallen to as low as -98°C (-144°F), which could have meant that the air temperatures at a typical 2-meter height could have been on the order of 94°C (or -137°F). These ultralow temperatures occurred in shallow topographic depressions near the highest part of the ice sheet, at elevations ranging from 3800 to 4050 meters. The team reported that these ultralow temperatures appeared to have occurred more frequently during the southern polar night in July and August when the Antarctic polar vortex was strong. Clear skies, extremely dry air and light winds are also necessary, which help allow the temperatures to fall in the small topographic depressions. The lowest measured surface air temperature on Earth is -89.2°C (-129°F) on 23 July 1983 at Vostok Station in Antarctica. [National Snow & Ice Data Center Newsroom]

CLIMATE FORECASTS

The South Pacific Oscillation could help forecast a possible El Niño in near future -- A meteorology professor at the University of Oklahoma wrote a guest post to the ENSO Blog of the ClimateWatch Magazine describing how seasonal forecasters should be looking to atmospheric and oceanic features in the South Pacific before judging the type of El Niño event that is anticipated over the next several months. He is pointing to the existence of a Southern Pacific Oscillation (SPO), or a pattern of sea level pressure (SLP) variations in the Southeast Pacific between latitudes of about 60°S and 35°S during Southern Hemisphere winter (June, July and August). According to his analysis of the current pressure patterns across the South Pacific, if an El Niño forms this year, it should be a "weak" Central Pacific event, similar to the one in 2004-2005, where above average sea surface temperatures should develop over the central equatorial Pacific near the Dateline. [NOAA Climate.gov News]

CLIMATE FORCING

Local winds could have large impact on some Western megafires -- Scientists from the National Center for Atmospheric Research (NCAR), NASA's Jet Propulsion Laboratory and the U.S. Forest Service have been studying the behavior of the 2014 King fire that burned more than 97,000 acres in California's Sierra Nevada mountain range during the Golden State's severe multi-year drought. Using data from airborne instruments and advanced computer simulations from NCAR, the team found that highly localized winds sometimes play a large role in creating large, destructive fires even when regional winds are weak. Very localized winds related to topography and winds created by the searing heat of the flames appear to be the reason for the sudden advance of the fire, which ran 15 miles up a steep canyon during one afternoon. [NASA Jet Propulsion Laboratory News]

CLIMATE AND SOCIETY

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

Historical Events:

30 July 1949...The state record temperature for Connecticut was established when the town of Greenville registered an afternoon high of 102 degrees. (The Weather Channel)
30 July 1965...The temperature at Portland, OR reached 107 degrees to equal their all-time record high. (The Weather Channel)
30 July 1999...At nine o'clock in the morning Chicago recorded its highest ever dew point temperature of 82 degrees. The temperature at the time was 88, resulting in a heat index of 108 degrees. The dewpoint is an indication of the amount of water vapor in the air. (National Weather Service files)
31 July 1861...Numerous world rainfall records were set at Cherrapunji, India as of this last day of July. These records include: 366.1 inches for a single 31-day month (during July 1861); 502.63 inches for two months (June-July 1861); 644.44 inches for three months (May-July 1861); 737.72 inches for four months (April-July 1861) and 1041.78 inches for 12 months (Aug. 1860-July 1861). (WMO, NWS)
31 July 1991...Roswell, NM closed out the month with a total of 6.68 inches of rain to set a new record for the month. (Intellicast)
31 July 1986...The temperature at Little Rock, AR soared to 112 degrees to establish an all-time record high for that location. Morrilton, AR hit 115 degrees, and daily highs for the month at that location averaged 102 degrees. (The Weather Channel)
31 July 1993...Alabama finished its hottest July on record since 1879, while receiving less than half the normal rainfall. Meanwhile, the Great Flood of 1993 was reaching its peak in the Midwest and was eventually responsible for 48 deaths and $23.1 billion in damage. (National Weather Service files)
31 July 1997...South Pole, Antarctica recorded their coldest July ever. The average temperature of -86.8 degrees broke the previous record of -83.6 degrees set in July 1965. (National Weather Service files)
1 August 1977...Excessive rains at Muduocaidang, China were responsible for establishing two world records, to include 33.07 inches in 6 hours and 55.12 inches in 10 hours. (WMO, NWS)
1 August 1985...A nearly stationary thunderstorm deluged Cheyenne, WY with rain and hail. Six inches of rain fell in six hours producing the most damaging flash flood of record for the state; a 24-hour precipitation record for the Cowboy State was also established with 6.06 inches. Two to five feet of hail covered the ground following the storm, which claimed twelve lives and caused 65 million dollars property damage. (Storm Data)
1 August 1993...San Francisco, CA hit 98 degrees, the hottest ever recorded for the city in August. (Intellicast)
3 August 1898...Philadelphia, PA had one of its worst thunderstorms ever when 5.84 inches fell in just 2 hours. The hydraulic pressure in the city sewers due to the force of the accumulated runoff caused overflows in toilets, basins and sinks to rise to second-floor levels in some cases. (Intellicast) (Accord's Weather Guide Calendar)
3 August 1914...Temperature reached an all-time August high of 96 degrees for Calgary, Alberta. (The Weather Doctor)
3 August 1970...Hurricane Celia made landfall near Port Aransas on the Texas coast, producing wind gusts to 161 mph at Corpus Christi, and estimated wind gusts of 180 mph at Arkansas Pass. Even at Del Rio, 250 miles inland, Celia produced wind gusts to 89 mph. The hurricane was the most destructive of record along the Texas coast causing 454 million dollars damage as 8950 homes were destroyed on the Coastal Bend. Celia also claimed eleven lives and injured 466 people. (David Ludlum) (The Weather Channel) (Intellicast)
3 August 1987...Beckley, WV established an all-time record with an afternoon high of 93 degrees. (The National Weather Summary)
3 August 1990...Highest temperature recorded in the United Kingdom prior to 2003 heat-wave was 98.8 degrees at Cheltenham, England: (The Weather Doctor)
3 August 1995...South Bend, IN received 4.83 inches of rain in 24 hours to set the city's greatest daily rainfall record. (Intellicast)
3 August 2011...Little Rock, AR set their all-time high temperature record of 114 degrees. (National Weather Service files)
4 August 1644...The first weather observations made on a regular basis in the U.S. were taken by Reverend John Campanius Holm in Wilmington, DE. (National Weather Service files)
4 August 1881...The highest temperature recorded anywhere in Europe was 122 degrees Fahrenheit reported at Seville, Spain. (NCDC)
4 August 1930...The temperature at Moorefield, WV soared to 112 degrees to establish a state record, having reached 110 degrees the previous day. This new record for the Mountain State was subsequently tied in July 1936. (The Weather Channel)
4 August 1960...The Vostok station in Antarctica recorded a record low temperature of 127 degrees below zero on the Fahrenheit scale, which remained the lowest recorded global temperature until 1983. (The Weather Doctor)
4 August 1961...Spokane, WA reached an all-time record high temperature of 108 degrees. Kalispell, MT set an all-time record with a reading of 105 degrees. (The Weather Channel)
5 August 1843...A spectacular cloudburst at Chester Creek, near Philadelphia, PA turned the small creeks and streams entering the Delaware River into raging torrents. As much as sixteen inches of rain fell in just three hours at Concord, which still stands as the greatest amount of precipitation in a three-hour span in the U.S. (David Ludlum) (Intellicast)
5 August 1961...The temperature at Ice Harbor Dam, WA soared to 118 degrees to equal the state record established at Wahluke on 24 July 1928. The afternoon high of 111 degrees at Havre, MT was an all-time record for that location. (The Weather Channel)
5 August 1988...Floods ravaged parts of Sudan during August, the result of 8.27 inches of rain that fell in Khartoum in 13 hours on the 4^th and 5^th. The previous 24-hour record at Khartoum was 3.46 inches. More than one million people were made homeless. At least 96 died in Sudan's worst flooding since 1946. (Accord's Weather Guide Calendar)
5 August 1994...Fairbanks, AK soared to 93 degrees for the highest ever August temperature. (Intellicast)
5-6 August 1959...A bucket survey showed that thunderstorms dropped 16.70 inches of rain on parts of Decatur County, IA. The total was accepted as Iowa's 24-hour rainfall record. (The Weather Channel)

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