WEEKLY CLIMATE NEWS

14-18 May 2018

ITEMS OF INTEREST

Hurricane season to begin in the eastern North Pacific -- The official 2018 hurricane season in the eastern North Pacific Ocean basin begins this Tuesday, 15 May 2018. The hurricane season in the central North Pacific basin and the North Atlantic basin, including the Caribbean Sea and the Gulf of Mexico will begin in two weeks on 1 June. The official hurricane seasons in all of these basins end on 30 November 2018.
Zenithal Sun -- This week marks one of the two times during the year when the noontime sun is directly overhead to residents on the Big Island on about 14 May at South Cape (Ka Lae at 18.9 deg North latitude and 155.68 degrees West longitude) and on 18-19 May at Hilo; those on Oahu (Honolulu metropolitan area) will experience the noon sun at the zenith in approximately two more weeks (25-27 May). The sun will again be over the Big Island during the last week of July. [US Naval Observatory, Data Services]
North American Safe Boating Week -- On this upcoming Saturday (19 May), the 2018 National Safe Boating Week will start and run through Friday, 25 May. This week helps launch the 2018 North American Safe Boating Campaign. Check the Safe Boating Week site maintained by the National Safe Boating Council. In addition, Friday 18 May has been designated as "Wear Your Life Jacket to Work Day".

CURRENT CLIMATE STATUS

Arctic Ocean's "old sea ice" is disappearing -- The National Snow and Ice Data Center (NSIDC) recently reported that as of early March 2018, only two percent of the Arctic's sea ice was at least five years old, which represents the lowest percentage of such old ice during wintertime in the satellite record. The observations were made at the time of year when the sea ice coverage reaches its winter maximum. The record low percentage of multiyear ice this past March continued long-term trend of Arctic sea ice decline. Multiyear or "old sea ice" tends to be thicker than "young ice" and takes longer to melt. A low percentage of "old sea ice" would be indicative of smaller sea ice coverage, as young or first-year ice melts more easily during the summer season. [NOAA Climate.gov News]

CURRENT CLIMATE MONITORING

Gains in nation's air quality are slowing -- A study conducted by an international team of researchers has found that the air quality across the United States has not been improving as rapidly in recent years, especially in terms of two key air pollutants. The team analyzed extensive satellite and ground-based measurements of nitrogen oxides and carbon monoxide, finding that levels of pollutants contributing to the formation of ground-level ozone or smog have failed to continue a fairly steady decline as estimated by the U.S. Environmental Protection Agency. [NCAR/UCAR AtmosNews]
Technology adopted to automate weather balloon launches -- NOAA's National Weather Service (NWS) is currently conducting a demonstration project involving the automatic launching of instrumented weather balloons (radiosondes) from at least two autolaunch stations in Alaska. Eventual automation of the radiosonde launches from all thirteen NWS upper-air stations in Alaska is intended as a cost-saving measure, freeing staff from manual launches at these remote stations to spend more time improving public service. [NOAA News]
Six reasons for the eventual switch to automated radiosonde launches by NWS are enumerated. [NOAA Stories]

CLIMATE FORCING

Rising global temperatures contributed to 2016 record Arctic heat -- A contractor with NOAA's Climate Program Office wrote an article for the ClimateWatch Magazine describing the record warm year of 2016 in the Arctic region, where some daily temperature departures were 30 to 40 Fahrenheit degrees above normal. She documented how this unprecedented warmth is a signature of a changing climate with increasing global temperatures. A map of the observed temperature anomalies during 2016 across the Arctic was compared with two computer simulations of the average temperature for 2016. One of the simulations was based upon only natural influences, using estimated conditions from the late nineteenth century, while the other simulation not only included the natural influences, but also added the effects due to human influences, such as increased greenhouse gas levels. The map produced from the first simulation showed some temperature increase across the Arctic, while the second map generated by the second simulation showed temperature increases comparable to the observed 2016 temperature anomalies. The conclusion drawn by the scientists who ran the simulations was that the record warm Artic in 2016 was due in part by natural variability, including the influence of the strong 2015-16 El Niño event in the tropics, while a significant contribution was due to changes in climate due to human activity. [NOAA Climate.gov News]
Plumes of sulfur dioxide and ash seen to rise from Hawaii's Kilauea Volcano -- Sensors onboard the NASA/NOAA Suomi NPP satellite and NASA's Terra satellite detected elevated amounts of sulfur dioxide and volcanic ash in a plume emanating from the Kilauea Volcano on Hawaii's Big Island. The plume that was lofted from the volcano was carried toward the southwest on the prevailing northeast trade winds that blow across the Hawaiian Islands. The Ozone Mapping Profiler Suite (OMPS) sensor on the Suomi NPP satellite detected elevated levels of sulfur dioxide before the main eruption on 3 May. [NASA Earth Observatory]
The Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite detected a plume of volcanic ash heading toward the southwest three days after the eruption. The MISR instrument was able to detect the height of the plume to be approximately 6500 feet altitude near the volcano's fissure, a sufficiently low altitude that could cause health problems for residents downwind of the volcano because of the high levels of ash particles and sulfur dioxide. [NASA Feature Image]
Powerful Atlantic hurricanes tend to strengthen faster than 30 years ago -- Scientists at the U.S. Department of Energy's Pacific Northwest National Laboratory and NOAA's Atlantic Oceanographic and Meteorological Laboratory have found that Atlantic hurricanes tend to intensify more rapidly now than they did 30 years ago due largely to a natural climate phenomenon that affects the water temperature in the Atlantic where hurricanes are strengthening, especially the powerful ones. The researchers analyzed thirty years of hurricane data obtained from satellites. They focused on the rapid intensification process, when the maximum wind speed in a hurricane increases by at least 25 knots (28.8 mph) within a 24-hour period. This process tends to occur in nearly all major hurricanes including two category 4 and two category 5 hurricanes (on the Saffir-Simpson Scale) in 2017. The team found a climate cycle known as the Atlantic Multidecadal Oscillation (AMO) to be central to the increasing intensification of hurricanes. The AMO, which has a periodicity ranging from 60 to 80 years, broadly affects conditions such as sea temperature that are known to influence hurricanes. Since the 1990s, the AMO has been positive, which is associated with higher sea surface temperatures in the North Atlantic. [Pacific Northwest National Laboratory News]

CLIMATE FORECASTS

Updated El Niño/Southern Oscillation (ENSO) Diagnostic Discussion is released -- Late last week forecasters at NOAA's Climate Prediction Center (CPC) and the International Research Institute for Climate and Society (IRI) released their monthly El Niño/Southern Oscillation (ENSO) Diagnostic Discussion. They reported that during the month of April 2018, sea surface temperatures (SST) across the equatorial Pacific Ocean (especially in regions called Niño-3+4) approached near-average values, while SST levels remained below-average in the eastern equatorial regions of the basin (in regions identified as Niño-1+2). The SST pattern indicated that ENSO-neutral (neither El Niño nor La Niña) conditions had returned. Atmospheric conditions suggested that the La Niña conditions experienced earlier this year continued to weaken. Most of the prediction models used by the forecasters indicate ENSO-neutral to continue at least through the Northern Hemisphere meteorological summer 2018 (June-August), with some suggesting an increased chance to 50 percent for the onset of an El Niño during the boreal winter of 2018-19. Therefore, the forecasters issued their last La Niña Advisory under CPC's ENSO Alert System Status. [NOAA Climate Prediction Center]
An ENSO blog for the ClimateWatch Magazine was written by a contractor with CPC that describes the demise of the La Niña that was evident across the Pacific since late 2017. She also reviewed the temperature and precipitation patterns across North America during the recent three months (February-April 2018), shown in the form of anomaly maps (arithmetic differences between observed temperatures or precipitation during the three months in 2018 and the 1981-2010 averages for the corresponding months). She pointed to the temperature pattern in 2018 featuring a cold northern U.S. and southern Canada, but a warm Gulf Coast and Texas. This pattern is quite similar to what is often expected in a La Niña winter. Furthermore, a dry Southwest and a wet Southeast during early 2018 were similar to that associated with a La Niña. Finally, she considered the possibility of the onset of El Niño conditions by next winter. [NOAA Climate.gov News]
An El Niño forecast from Down Under -- Forecasters with the Australian Bureau of Meteorology recently issued an updated forecast, in which they reported that ENSO-neutral conditions were continuing currently across the tropical Pacific, as atmospheric and oceanic indicators of ENSO were generally at near average levels. They also noted that nearly all international forecast models indicated ENSO-neutral conditions should continue through meteorological winter in the Southern Hemisphere (or summer in the Northern Hemisphere) covering June through August, even though sea surface temperatures were expected to increase. Only one model suggested sea surface temperatures reaching the El Niño threshold by September. Therefore, the Bureau's ENSO Outlook status remains as "Inactive." [Australian Government Bureau of Meteorology]
National Hurricane Center releases its forecast verification report for 2017 -- During the past week NOAA's National Hurricane Center (NHC) released its 73-page Forecast Verification Report for the 2017 hurricane season in the North Atlantic and eastern North Pacific basins. NHC issued 407 official forecasts for the North Atlantic basin since the 2017 hurricane season had above-normal activity for that basin. The official NHC track forecasts in the Atlantic basin were quite successful in 2017, with records for track accuracy set at all forecast times as indicated by smaller mean NHC official track forecast errors than in previous seasons. However, mean official intensity errors for the Atlantic basin in 2017 were above the 5-year means for forecasts with lead-times ranging from 12 to 48 hours, but near the means at the longer lead times. NHC issued 334 official forecasts for the eastern North Pacific basin, which was close to average. Although the forecasts where skillful, no records for track accuracy were set in this basin in 2017. Official intensity forecast errors in the eastern North Pacific basin were lower than the 5-year means at all forecast times. [NOAA National Hurricane Center]

CLIMATE AND THE BIOSPHERE

Atmospheric seasonal changes could signal alien life on distant planets -- Researchers from the University of California Riverside and colleagues from other institutions claim that atmospheric fingerprints of life, called biosignatures, can be used to detect the possibility of life on distant planets using next-generation telescopes. These telescopes would spectroscopically measure the composition of gases surrounding the planets to assess the seasonal variations. The researchers are developing the first quantitative framework for dynamic biosignatures based on seasonal changes in the Earth's atmosphere of such gases associated with life such as oxygen, carbon dioxide and methane. [University of California Riverside News]

PALEOCLIMATE RECONSTRUCTION

Extracting Easter Island's climatic history from sediment cores -- A team of scientists from Columbia University, the College of William and Mary, the University of Massachusetts Amherst and Chile's Universidad Academia de Humanismo Cristiano recently collected sediment cores from three wetlands on Rapa Nui (Easter Island) that will be used to investigate various aspects of climatic, environmental, and human land-use history on this island off the coast of Chile. The cores should provide geologic records that likely span the past 30,000 years on Rapa Nui. [Lamont-Doherty Earth Observatory News]

CLIMATE AND SOCIETY

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

Historical Events:

14 May 1834...The greatest snowstorm ever to occur in May hit the Northern Atlantic coastal states. The hills around Newbury, VT were covered with up to 24 inches of snow and the higher elevations around Haverhill, NH received up to three feet. (Intellicast)
14 May 1896...The mercury plunged to 10 degrees below zero at Climax, CO, the lowest reading of record for the U.S. during the month of May. (David Ludlum) This record has since been broken in May 1964 by a reading of 15 degrees below zero at White Mountain in California. (NCDC)
14 May 2001...A storm stalled south of Nova Scotia drenching Halifax with 3.89 inches of rain, the greatest daily May rainfall since records began in 1871. (The Weather Doctor)
15 May 1968...Only tornado of record to have ever touched down in Alaska was spotted near Anchorage. (The Weather Doctor)
Check A tornado touched down southwest of Anchorage, Alaska. It was the second of just three tornadoes reported in Alaska since 1950. (National Weather Service files)
16 May 1917...Marquette, MI had its latest opening of navigation on Lake Superior in history. (Intellicast)
16 May 1924...The temperature at Blitzen, OR soared to 108 degrees to set a state record for the month of May. The record was later tied at Pelton Dam on the 31 May 1986. (The Weather Channel)
17 May 1997...Two inches of snow fell at Herman, MI, marking the last measurable snow for the 1996-1997 snow season. The 384.0 inches for this just concluded snow season broke a state snowfall record that was set the previous 1995-1996 season of 347.0 inches. The average snowfall at Herman is 239.7 inches. (Accord's Weather Guide Calendar)
17 May 1979...A reading of 12 degrees at Mauna Kea Observatory (elevation 13,770 feet) established an all-time record low temperature for the state of Hawaii. (The Weather Channel)
18 May 1960...Salt Lake City, UT received an inch of snow, marking their latest measurable snowfall of record. (The Weather Channel)
18 May 1980...Mount St. Helens in Washington State erupted, ejecting smoke and ash to a height of 63,000 feet. The smoke plume rose to a height of 80,000 feet. The ground was covered with heavy ash to the immediate northeast and visibility was reduced to less than one mile for a downwind distance of 400 miles. Five deaths were caused and over 2000 people were evacuated due to mudslides and flooding when the snowpack melted. Small particles in the cloud reached the East Coast in 3 days and circled the world in 19 days. (David Ludlum) (Intellicast)
19 May 1780...The infamous "dark day" in New England tradition occurred as noon was nearly as dark as night. Chickens went to roost, and many persons were fearful of divine wrath. Forest fires to the west of New England caused the phenomena. (David Ludlum)
19 May 1955...Lake Maloya, NM received 11.28 inches of rain in 24 hours to establish a state record. (The Weather Channel)
19 May 1962...An all-time May record was set when the temperature climbed to 99 degrees at Central Park in New York City. (Intellicast)
20 May 1996...Bridgeport, CT soared to 97 degrees for its highest temperature on record in May. (Intellicast)

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