WEEKLY CLIMATE NEWS

28 May - 1 June 2018

ITEMS OF INTEREST

Change in season -- Meteorological spring in the Northern Hemisphere, the three-month span from March through May, concludes next Thursday (31 May 2018), while meteorological summer (June, July and August) will commence on the following day.
Hurricane season to begin in the North Atlantic and Central North Pacific -- The 2018 hurricane seasons in the North Atlantic Ocean basin, including the Caribbean Sea and the Gulf of Mexico, along with the central North Pacific will begin this Friday, 1 June 2018. The 2018 hurricane season in the eastern North Pacific began two weeks ago on 15 May. The official hurricane seasons in all three basins will end on 30 November 2018.
High-quality maps of June 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 June 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.
June 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 April, 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.

CURRENT CLIMATE STATUS

Assessing the rarity of a landfall of a tropical cyclone in the Horn of Africa -- A meteorologist at NOAA's Climate Prediction Center recently wrote an "Event Tracker" blog for the ClimateWatch Magazine following the landfall of Tropical Cyclone Sagar along the northern coast of Somalia slightly more than one week ago. Winds reached 60 mph as Sagar made landfall, which would make Sagar the strongest landfalling tropical cyclone on record for Somalia. Sagar was responsible for 31 fatalities. He noted that Sagar was only the third tropical cyclone to have made landfall on Somalia's northern coast since quality records began. [NOAA Climate.gov News]

CURRENT CLIMATE MONITORING

A global climatology is developed for tropical cyclone eyes -- A team of scientists from NOAA's National Centers for Environmental Information and the Cooperative Institute for Meteorological Satellite Studies at University of Wisconsin-Madison have developed a global climatology of the sizes and locations of tropical cyclones based upon a 34-year long period of record running between 1982 and 2015. The researchers used a computer algorithm to examine over a quarter million individual infrared satellite images from the global Hurricane Satellite (HURSAT) dataset. They found that more than half of the tropical cyclones during this period had developed at least one eye and that these systems had an eye for at least 30 hours. Furthermore, half of the systems developed their first eye within two days of becoming a named tropical cyclone. Eyes were more frequent in Northern Hemisphere systems, although their Southern Hemisphere counterparts were typically larger. [NOAA NCEI News]
Operation IceBridge survey flights over the Arctic conclude for the season -- At the beginning of May, NASA's tenth annual Operation IceBridge in the Arctic was concluded after a series of 20 flights across the western basin of the Arctic Ocean and Greenland's fastest-changing glaciers during a six-week span. Operation IceBridge represents an annual airborne survey made by NASA scientists and their colleagues of the Arctic ice cover and the Greenland glaciers. These flights have been made as a temporary replacement for NASA's ICESat satellite that suffered a malfunction in 2009; this year's mission should be the final season as the ICESat-2 satellite is scheduled to be launched in September 2018. [NASA IceBridge Feature]

CLIMATE FORCING

A changing climate could lead to bigger atmospheric rivers -- A researcher from NASA's Jet Propulsion Laboratory and his colleagues claim that climate change is likely to intensify "atmospheric rivers" across most of the globe by the year 2100 by making them considerably longer and wider, while slightly reducing their number. Atmospheric rivers are long plumes of moisture-laden air that travel from the tropical and subtropical ocean basins to extratropical landmasses, often creating extreme weather events because of torrential rain and strong winds; some of the most famous atmospheric rivers are found to form over the Pacific Ocean and inundate coastal areas along the West Coast of North America. The team used projections from a climate model designed to simulate Earth's climate in 2100 where greenhouse gas emissions would continue at the current rate and an atmospheric river detection algorithm to identify atmospheric river events from the model simulations. The researchers found that the atmospheric rivers would increase in length and width by 25 percent, while the number of such rivers would decrease by 10 percent. [NASA Global Climate Change News]
"Traffic jams" in the upper atmospheric jet stream could cause abnormal weather and climate patterns -- Two atmospheric scientists from the University of Chicago offer an explanation for a mysterious and sometimes deadly weather pattern in which the upper tropospheric jet stream encircling the Earth would stall over a region. This stalling is often known as a "blocking pattern." In studying the jet stream's meanders during such a blocking pattern, the researchers found a mathematical explanation that was similar to that employed by transportation engineers to model and describe traffic jams on highways. Like traffic jams caused by convergence of vehicles associated by lower speed limits or converging highways, the blocking in the atmosphere would often occur where the background jet speed slows down due to mountains and coasts. The researchers believe that this explanation could help predict long-term patterns, including which areas may see more drought or floods, especially if climate change would possibly increase blocking. [University of Chicago News]
Unexpected rise in emissions of ozone-destroying chemical controlled by Montreal Protocol -- Scientists from NOAA and the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder have found that their measurements of global atmospheric concentrations of the ozone-depleting trichlorofluoromethane, or CFC-11, at 12 remote sites around the globe have been increasing despite the required end to its production in 2010 by the international Montreal Protocol. The unexpected increase in emissions of this gas, especially from 2014 to 2016, appears to be from new, unreported production that may be in eastern Asia. CFC-11, which was used as a foaming agent, is the second-most abundant ozone-depleting gas in the atmosphere and a member of the family of chemicals most responsible for the diminished concentrations in the ozone layer that forms over Antarctica each September. [NOAA Research News]

CLIMATE FORECASTS

Explanation of long-range weather and climate outlooks is provided -- A meteorologist in NOAA's Climate Prediction Center (CPC) wrote the ENSO blog for the ClimateWatch Magazine in which she explains how her colleagues at CPC prepare medium-range forecasts ranging between 6-10 days and 8-14 days as well as the longer-range monthly and seasonal (three-month) climate outlooks for the nation. She notes that these outlooks are based upon the probabilities that the anticipated temperature or precipitation would either be above, below or near the 30-year average. She also explains that forecasting the weather for up to two weeks involves consideration of the current state of the atmosphere, while the long-term climate outlooks involve consideration of atmospheric and oceanic processes and trends such as ENSO. [NOAA Climate.gov News]
Official hurricane outlooks issued -- During the last week, scientists with NOAA's Climate Prediction Center (CPC) released their outlook for the upcoming 2018 hurricane seasons in the North Atlantic basin, which includes the Caribbean Sea and the Gulf of Mexico, and the central North Pacific basin, which lies between the 140 degree West meridian of longitude and the International Dateline.

Their outlook for the North Atlantic basin indicates a 35 percent chance of an above-normal season, a 40 percent chance of a near-normal season, and only a 25 percent chance of a below-normal season in 2018. The forecasters predict a 70-percent likelihood of 10 to 16 named tropical cyclones (hurricanes and tropical storms with sustained surface winds of at least 39 mph), including five to nine of these tropical cyclones becoming hurricanes (maximum sustained surface winds of 74 mph or higher). Between one and four of these hurricanes could become major hurricanes (Category 3 hurricanes or greater on the Saffir-Simpson Hurricane Intensity Scale). The forecasted numbers include Subtropical Storm Alberto, a pre-season system that formed over the northwestern Caribbean at the end of last week. (Based upon long-term statistics, an average Atlantic season consists of 12 named tropical cyclones per year and the six hurricanes that normally form during each year. Three of these hurricanes typically become major hurricanes.) The forecasters based their near- to above-normal forecast in the frequency of named tropical cyclones in the North Atlantic basin for 2018 upon the possibility of weak El Niño conditions developing later in the season, near- or above-average sea-surface temperatures across the tropical Atlantic Ocean and Caribbean Sea, and the continuation of the high-activity era for Atlantic hurricane seasons since the mid 1990s. NOAA will update their 2018 Atlantic hurricane outlook in early August, just before the peak in the season. [NOAA News]
For comparison, hurricane expert Phil Klotzbach and colleagues at Colorado State University had released a forecast of the 2018 Atlantic hurricane season in early April that called for a slightly above-average season. They envisioned fourteen named tropical cyclones, which would include seven hurricanes. Of these hurricanes, the forecasters foresee three major hurricanes. [The Tropical Meteorology Project]
The CPC outlook for the central North Pacific basin suggests that this basin should experience a 40-percent chance of a near-normal hurricane season in 2018 and a 40-percent chance of an above-normal. A 20-percent chance exists for a below average activity. Their outlook calls for possible formation of three to six tropical cyclones, as compared with the long-term average of four to five tropical cyclones. The indication of an above average season is based upon a possible transition from current ENSO-neutral to weak El Niño conditions during the hurricane season, along with near- or above-average ocean temperatures in the main hurricane formation region, and near- or weaker-than-average vertical wind shear. [NOAA News]

CLIMATE AND THE BIOSPHERE

Minke whales are threatened by melting Antarctic sea ice -- A team of scientists from NOAA, the National Science Foundation and three research universities traveled to the waters surrounding the Antarctic Peninsula earlier this year to study minke whales, a type of baleen whale. The scientists were investigating how the melting of the sea ice surrounding the peninsula would affect these whales. Melting sea ice associated with a warming climate threatens krill populations, which are tiny, shrimp-like crustaceans that are the main food for the minke whales. The krill feed upon algae and phytoplankton that grow on the underside of sea ice. The scientists used several new tools to measure the underwater behavior of the whales, including whale-mounted, location-tracking video cameras and echosounders that provide near-instant measures of the biomass of krill swarms consumed by the whales. [NOAA National Centers for Coastal Ocean Science News]

PALEOCLIMATE RECONSTRUCTION

Long-term Asian dust fall records may affect climate change theory -- An international team of scientists from the U.S. and China have assembled a 550,000-year precipitation record for north-central China using the amount of the beryllium-10 isotope in samples of loess deposits to serve as a proxy indicator of precipitation. The loess is fine soil deposited after being blown year after year from central Asian deserts into north-central China. Analysis of this precipitation record revealed that changes in the intensity of the Asian summer monsoon corresponded to the waxing and waning of the polar ice caps. These findings suggest that changes in the climate across tropical and subtropical latitudes associated with changes in the monsoon circulation over Asia may have had as much of an effect on extratropical latitudes as the reverse, which is central to the commonly held Milankovitch theory of large-scale climate change. [University of Arizona News]

CLIMATE AND SOCIETY

A new international coalition launched on health, environment and climate change -- The heads of the World Health Organization (WHO), UN Environment and World Meteorological Organization (WMO) announced at the recent annual World Health Assembly that a new global coalition on health, environment and climate change was being launched. One of the overall goals of this coalition is the reduction of the 12.6 million deaths annually caused by environmental risks, especially due to air pollution. [World Meteorological Organization News]
Environmental stresses may have disrupted prehistoric peoples in Mississippi Delta -- Researchers from Vanderbilt University and the University of Illinois claim that prehistoric people of the Mississippi Delta may have abandoned a large ceremonial site near Dulac, LA due to environmental stress. The researchers used archaeological excavations, geologic mapping and coring, and radiocarbon dating to identify how Native Americans built and inhabited the 20-foot high Grand Caillou mound, beginning approximately 800 years ago, when Bayou Grand Caillou was a major and active river channel in the Lafourche subdelta. However, the site apparently was abandoned 600 years ago when Bayou Grand Caillou stopped carrying a significant portion of Mississippi River water and sediment. [Vanderbilt University News]
Earthweek -- Diary of the Planet [earthweek.com]

Historical Events:

28 May 1887...The temperature reached 97 degrees at San Francisco, CA, establishing a record high temperature for the month of May for the city. (Intellicast)
28 May 1942...The latest snowstorm of record for the state of Iowa left ten inches at LeMars, eight inches at Cherokee, and 7.5 inches at Waukon. Afternoon highs were in the lower 30s in parts of northwestern Iowa. (The Weather Channel)
28 May 1984...Sacramento, CA had its highest temperature ever recorded in the month of May, when the temperature reached 110 degrees, breaking the old record of 100 degrees set in 1932. (Intellicast)
28 May 2003...A new Nevada maximum temperature record for May was set when the high temperature at Battle Mountain, NV rose to 102 degrees. (The Weather Doctor)
29 May 2000...A new national maximum temperature record for May is set when the high temperature in Death Valley, CA soared to 122 degrees. (The Weather Doctor)
30 May 1948...The Columbia River reached its highest stage since 1894. A railroad bed acting as a dam gave way during a flood along the Columbia River destroying the town of Vanport, OR. The nearly 18,700 residents escaped with little more than the clothes on their backs. Damage was estimated at 101 million dollars and 75 lost their lives. (David Ludlum) (Intellicast) Twenty carloads of glass were needed in Denver, CO to replace that destroyed by a severe hailstorm. (The Weather Channel)
30 May 1985...The temperature in Oklahoma City, OK reached a sizzling 104 degrees, making it the highest ever for so early in the season. This also marked the very first time the temperature had reached the 100-degree plateau in the month of May at Oklahoma City. (Intellicast)
30 May 1986...Hanford, WA hit a scorching 104 degrees, breaking the all-time record high temperature for May for Eastern Washington. Yakima, WA hit 102 degrees, a record high for the month of May for Yakima. Records also fell at Boise, ID and Reno, NV. (Intellicast)
31 May 1889...The Johnstown, PA disaster occurred, the worst flood tragedy in U.S. history. Heavy rains totaling 4 to 10 inches over the previous 36 hours collapsed the South Fork Dam sending a thirty-foot wall of water rushing down the already flooded Conemaugh Valley. The wall of water, traveling as fast as twenty-two feet per second, swept away all structures, objects, and people, practically wiping out Johnstown. About 2100 persons perished in the flood. (David Ludlum)
31 May 1935...The U.S. record 2-hour rainfall amount was set at D'Hanis, TX, with exactly 15 inches. The U.S. 2.75-hour record rain was also set with 22 inches. (National Weather Service files)
31 May-1 June 1941...Thunderstorms deluged Burlington, KS with 12.59 inches of rain to establish a 24-hour rainfall record for the Jayhawk State. (The Weather Channel)
31 May 1973...Canada's sunniest month ends as Eureka, Northwest Territories recorded 621 hours of bright sunshine. (The Weather Doctor)
31 May 1983...Albany, NY experienced its wettest spring (March-May) in 109 years of records as 19.54 inches of precipitation was recorded. (Intellicast)
31 May 1986...The Weather Service Office in Washington, DC reported its driest spring on record with only 3.47 inches of precipitation from 1 March to 31 May. (Intellicast)
31 May 1988...Hot and humid weather prevailed in the eastern U.S. Thirteen cities reported record high temperatures for the date. Cape Hatteras, NC reported their first ninety-degree day in May in 115 years of records. (The National Weather Summary)
31 May 1991...Norfolk, VA hit 100 degrees, setting a new all-time record high for the month of May. (Intellicast)
31 May 1992...This May was the driest on record for Chicago, IL and Rockford, IL. Only 0.30 inches of rain fell at Chicago and Rockford had a paltry 0.48 inches. The total rainfall at El Paso, TX of this past month was 4.22 inches, making this the wettest May ever for the city. The normal rainfall for May is only 0.24 inches, which means that this month rainfall total was 1758 percent of normal! (Intellicast)
Month of June...According to a 1969 US Army technical report, the average dewpoint temperature at Ras Andahglie and Assab, Eritrea (Ethiopia) average slightly more than 84 degrees F. (Accord's Weather Guide Calendar)
1 June 1907...Sarmiento, Argentina reported a temperature of 29 degrees below zero, the lowest temperature ever recorded in South America. (The Weather Doctor)
1 June 1941...Burlington, KS received 12.59 inches of rain, which set a 24-hour precipitation record for the Jayhawk State. (NCDC)
1-17 June 2001...The deadliest and costliest tropical storm in US history, Tropical Storm Allison, wandered westward across the tropical Atlantic and crossed over into the Pacific before reversing and moving back into the Caribbean and Gulf of Mexico. On 1 June the tropical wave, which eventually evolved into TS Allison, moved into the Gulf of Tehuantepec on the Pacific coast of Mexico after moving westward across the tropical Atlantic and the Caribbean from the west coast of Africa on 21 May. On the 2^nd, a cyclonic (counterclockwise) circulation developed to the south-southeast of Salma Cruz, Mexico, but the low-level circulation became ill defined as the system moved inland on the 3^rd over southeastern Mexico and western Guatemala. This system intensified again and eventually moved northward to the Texas Gulf Coast and then eastward to the Atlantic before turning into an extratropical storm in mid-June. (Accord's Weather Guide Calendar)
1 June 2005...The UV (ultraviolet) Index in Toronto, Ontario reached 11 or Extreme on the 5-category UV scale, marking the first time the new extreme category has ever been attained in Canada. (The Weather Doctor)
2 June 1917...The temperature at Tribune, KS dipped to 30 degrees to establish a state record for the month of June. (The Weather Channel)
3 June 1905...Seattle, WA received its heaviest ever 24-hour June rainstorm with 1.42 inches falling. (Intellicast)

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