WEEKLY CLIMATE NEWS

16-20 July 2018

ITEMS OF INTEREST

Zenithal Sun -- Residents of Honolulu will experience a noontime sun that would be directly overhead during this past weekend and at the start of this week (15-17 July). This occurrence of a zenithal sun is one of the two times during the year when the noontime sun is directly overhead to residents of Honolulu and the Hawaiian Island of Oahu. The other time when Oahu experienced a zenithal sun was in late May. [US Naval Observatory, Data Services]
Commemorating the world's highest recorded temperature -- NOAA's National Centers for Environmental (NCEI) updated its feature of the measurement of the world-record high temperature at Greenland Ranch in California's Death Valley on the 105th anniversary of this event. The cooperative observer's thermometer on the afternoon of 10 July 1913 registered 134 degrees F, which has now been deemed the world's record high temperature according to the World Meteorological Organization. A copy of the July 1913 Cooperative Observer Form that shows the 134-degree entry for the data is provided. The reasons why Death Valley experiences exceptionally high temperatures are addressed. [NOAA NCEI News]
Remembering the deadly 1995 Midwestern heat wave -- NOAA's National Centers for Environmental Information (NCEI) posted a feature that describes the intense heat wave that spread across a large section of the Midwest, which resulted in the deaths of 583 people in the Chicago (IL) metropolitan area because of the extended heat. This heat wave began on 12 July 1995 and continued for four days, with daytime temperatures across the region reaching 104 degrees and nighttime temperatures falling only to the upper 70s and low 80s because of high levels of atmospheric humidity. The combination of triple digit air temperatures and dewpoints in the upper 70s and low 80s resulted in heat indices reaching 125 degrees. [NOAA NCEI News]

CURRENT CLIMATE STATUS

National weather and climate reviewed for June 2018 -- Scientists at the NOAA National Centers for Environmental Information (NCEI) recently reported on their analysis of preliminary weather data collected during the month of June 2018. They found:

The monthly temperature averaged across the coterminous United States for that month was 71.5 degrees Fahrenheit, which was 3.0 Fahrenheit degrees above the 20th-century (1901-2000) June average. Consequently, this past June was the third warmest June since 1895 when comprehensive climate records became available nationwide. The majority (37) of the 48 contiguous United States reported above- to much above-average monthly temperatures for June 2018. Fifteen states running from the Four Corners (Arizona, Colorado, New Mexico and Utah) eastward to the Carolinas and from Texas north to North Dakota reported statewide average temperatures for June that ranked within the top 10 of their respective 124 years of record. New Mexico had a statewide June temperature that was second highest on record, while Colorado and Texas had their third warmest June. On the other hand, only two states, Maine and Vermont in New England, had statewide average temperatures that were below-average temperatures. Nine states in the Northwest and Northeast had near-average temperatures.
The maximum (or daytime) temperature for June the 48 contiguous United States was 2.8 Fahrenheit degrees above the 20th century average, which was the 10th highest in 124 years. The minimum (nighttime) temperature for the "Lower 48" was 3.1 Fahrenheit degrees above the 20th century average, which was the second highest minimum June temperature on record. Iowa, New Mexico and Texas had their highest statewide minimum temperatures on record.
The June 2017 statewide temperature average for Alaska was the 40th highest in the state's period of record that extends back to 1925.
The nationwide average precipitation for June 2018 was 3.08 inches, which was 0.15 inches above the 20th-century average, making that month the 49th wettest (or 76th driest) June in 124 years.
Seventeen states across the northern Rockies, the northern Plains, the Midwest and the Middle Atlantic States had above to much-above average June statewide precipitation totals. Iowa reported its tenth wettest June since 1895, while Kentucky had its eleventh wettest June and Indiana had its twelfth wettest. Conversely, states scattered across the West and the lower Mississippi Valley registered below- to much-below average precipitation for June. Utah reported its sixth smallest average precipitation totals since 1895. Elsewhere, near average statewide June precipitation were reported across the South and Northeast.
This past June was the eleventh driest in Alaska for the last 94 years.

NOAA NCEI State of the Climate

NOAA/NCEI]

June national drought report -- The National Centers for Environmental Information has posted its June 2018 drought report online. Using the Palmer Drought Severity Index, approximately 23 percent of the coterminous United States experienced severe to extreme drought conditions at the end of June, while eight percent of the area had severely to extremely wet conditions.

CURRENT CLIMATE MONITORING

List of nation's billion-dollar weather & climate disasters updated for first half of 2018 -- NOAA's National Centers for Environmental Information recently updated its "U.S. Billion-Dollar Weather & Climate Disasters 1980-2018" through the first week of July 2018. This updated list includes six weather and climate disaster events with losses exceeding $1 billion each across the United States during the first six months of 2018. These events consisted of two winter storms and four severe storm events involving tornadoes, damaging straight-line thunderstorm winds and large hail. Overall, these events in 2018 resulted in the deaths of 36 people that accompanied the significant economic effects on the areas impacted. [NOAA/NCEI]
Decline in Great Lakes ice cover is seen over last four decades -- A team of scientists from NOAA's Great Lakes Environmental Research Laboratory (GLREL) and the University of Michigan recently reported on their analysis of the Great Lakes ice climatology dataset for the last 45 winters (1973-2017). They found a marked decline in the maximum extent of winter ice cover on all the lakes over the past four decades, with the greatest declines occurring on Lakes Superior, Huron, St. Clair, and Erie. Since Great Lakes ice cover appears to be a sensitive indicator of regional climate and climate change, the decreasing maximum ice extent of Great Lakes ice is attributed to a combination of natural climate influences, such as the El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO), as well as influences from anthropogenic forced climate change. The ice cover also affects the ecosystem of the Lakes along with the people who rely upon this ecosystem. [NOAA NCEI News]

CLIMATE FORECASTS

Updated El Niño/Southern Oscillation (ENSO) Diagnostic Discussion is released -- 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 late last week. They reported an ENSO-neutral situation continued through June 2018, with slightly above-average sea surface temperatures (SST) found across the eastern and central equatorial Pacific Ocean. A relatively warm volume of water was expanding upward from below in the eastern Pacific. In addition, other oceanic and atmospheric conditions remained close to average, suggestive of the continuation of an ENSO-neutral situation with neither El Niño nor La Niña conditions prevailing. The prediction models used by the forecasters indicate a continuation of the ENSO-neutral conditions through the remainder of Northern Hemisphere summer (June, July and August), with the majority of the models indicating the likely onset of an El Niño by the start of boreal autumn (September through November). Therefore, the forecasters have continued an El Niño Watch as part of the CPC's ENSO Alert System Status, since they increased the chance of El Niño conditions occurring in boreal autumn to approximately 65 percent and give about a 70 percent chance for El Niño in Northern Hemisphere's 2018-2019 winter season. [NOAA Climate Prediction Center] Note: The criteria used for CPC's ENSO Alert System is available.
An ENSO blog was written by a contractor with NOAA's Climate Prediction Center that explains the decision-making process that CPC and IRI forecasters use in determining the existence of El Niño conditions. She notes that ENSO-neutral conditions are continuing despite a recent warming of the waters in the deeper region of the eastern equatorial Pacific and a steady rise in the sea surface temperatures in a region of the central equatorial Pacific (called Niño3.4) used as a standard to determine the occurrence of an El Niño or La Niña. She also explains why the forecasters make ENSO forecasts, as these are important in the issuance of CPC seasonal outlooks for the upcoming Northern Hemisphere winter (December-February). [NOAA Climate.gov News]
An El Niño forecast from Down Under -- Forecasters with the Australian Bureau of Meteorology recently issued an updated ENSO forecast, in which they reported a continuation of ENSO-neutral conditions. However, they note that the latest model outlooks along with a recent warming in the tropical Pacific Ocean indicate that the likelihood of El Niño forming in Southern Hemisphere spring (September-November) has increased. Therefore, they have changed the Bureau's ENSO Outlook to "El Niño WATCH," meaning that the likelihood of El Niño forming during the remainder of 2018 is approximately 50%. [Australian Government Bureau of Meteorology]

CLIMATE AND THE BIOSPHERE

Smaller harmful algal bloom predicted this summer for western Lake Erie -- Late last week scientists from NOAA and the partner institutions of Ohio Sea Grant, Ohio State University, Heidelberg University and University of Toledo predict a harmful algal bloom (HAB) in western Lake Erie for the 2018 summer that would be smaller than the previous year, but larger than in 2016, which had a relatively mild bloom. The anticipated bloom should also be much smaller than the record 2015 bloom. This 2018 seasonal forecast involves the generation of a severity index based upon numerical models that involve assessing and predicting the nutrient runoff. In addition, the hope is for more accurate forecasts, since NOAA will increase use of data obtained from the European Space Agency's Sentinel-3a satellite. This Earth observation satellite is dedicated to oceanography that is part of the European Union's Copernicus program. The satellite, which was launched in 2016, measures coastal water color and shows the location of HABs. [NOAA News]

PALEOCLIMATE RECONSTRUCTION

Recent heatwave and drought helps reveal ancient site in Ireland -- A drone recently captured images of 200-meter diameter circles in a field in the Boyne Valley of Ireland's County Meath. These previously undetected circles in the vegetation and soil appear to be a "henge," or a type of circular earthwork relic from 5000 years ago during the late Neolithic or early Bronze Age. A lack of rainfall and recent hot weather are credited with the discovery, as the grass in the fields surrounding the henge had turned yellow because of the lack of soil moisture, while the grass over the ancient structures remained relatively green. [BBC News]

CLIMATE AND SOCIETY

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

Historical Events:

17 July 1934...One of the worst heat waves in the nation's history began. During the last two weeks of July, extreme heat claimed 679 lives in Michigan, with 300 of them in Detroit alone. (National Weather Service files)
17 July 1972...South America's lowest temperature, 38 degrees below zero, was attained at San Juan, Argentina. (National Weather Service files)
17 July 1987...Slow-moving thunderstorms caused flooding on the Guadalupe River in Texas resulting in tragic loss of life. A bus and van leaving a summer youth camp stalled near the rapidly rising river, just west of the town of Comfort, and a powerful surge of water swept away 43 persons, mostly teenagers. Ten drowned in the floodwaters. Most of the others were rescued from treetops by helicopter. (The National Weather Summary) (Storm Data)
17-18 July 1996...Heavy rains were responsible for unprecedented flooding across north central and northeast Illinois, resulting in hundreds of millions of dollars in damage. Aurora, IL received 16.91 inches of rain, which established a new 24-hour precipitation record for the Prairie State. Approximately 60 percent of the city's homes were affected by flooding. At Romeoville, 10.36 inches of rain fell. Interstates were closed and some towns were isolated. Rampaging floodwaters scoured out roads near Dayton, leaving gravel and sand deposits to twenty feet high. (NCDC) (Accord's Weather Guide Calendar)
18 July 1889...A cloudburst in West Virginia along the small creeks in Wirt County, Jackson County and Wood County claimed twenty lives. Rockport, WV reported 19.00 inches of rain in two hours and ten minutes that Thursday evening, setting a 24-hour precipitation record for the Mountain State. Tygart Creek rose 22 feet in one hour, and villages were swept away on Tygart, Slate, Tucker, and Sandy Creeks. (The Weather Channel) (NCDC)
18 July 1942...A record deluge occurred at Smethport in northern Pennsylvania, with 30.70 inches in just six hours. Several additional national records including 3-hour rainfall (28.50"), 4.5-hour rainfall (30.70"), and 12-hour rainfall (34.30"). The 24-hour rainfall total for the day was 34.50 inches, which set a maximum 24-hour precipitation for the Keystone State. The downpours and resultant flooding in Pennsylvania were devastating. (David Ludlum) (Intellicast) (NCDC)
18 July 1955...In Martinstown, England, eleven inches of rain fell in a 15-hour period on this day believed to be the 24-hour greatest rainfall for the United Kingdom. (The Weather Doctor)
18-19 July 1979...A 30-foot high tsunami wave leveled four Indonesian villages on the Sunda Islands during the night. The wave swept 1500 feet inland, causing 589 deaths among the sleeping villagers. A landslide from Mount Werung (Lomblen Island) caused the tsunami. (Accord's Weather Guide Calendar)
18-21 July 1996...Between six and twelve inches of rain fell on an already saturated Saguenay River Valley of Quebec, producing Canada's first billion-dollar disaster ($1.5 billion). Flooding destroyed or damaged 1718 houses and 900 cottages. Ten people were killed and 16,000 were evacuated. Roads and bridges disappeared. (Accord's Weather Guide Calendar) (The Weather Doctor) (Wikipedia)
18 July 1996...Aurora, IL received 16.91 inches of rain, which established a new 24-hour precipitation record for the Prairie State. (NCDC)
18-22 July 1997...Hurricane Danny, the only hurricane that made landfall in the continental US in 1997, moved inland into coastal Alabama at a snail's pace. Radar storm total estimates of 43 inches over Mobile Bay. A torrential 32.52 inches of rain fell on 19-20 July at Dauphin Island Sea Lab, establishing a 24-hour maximum precipitation record for Alabama. (NCDC) (Accord's Weather Guide Calendar)
19 July 1886...A hurricane from the Gulf of Mexico crossed Florida causing great damage from Cedar Keys to Jacksonville. This was the third hurricane in one month to cross the Florida peninsula. (David Ludlum) (Intellicast)
19 July 1955...The Yarkon Water Project was opened to supply water to Negev desert in Israel. The Yarkon "flows" through the most densely populated areas of the country to the Mediterranean. The river has deteriorated rapidly since the 1950's due to excessive draining for irrigation by the National Water Carrier, with marked decline in water quality, animal habitats, flora and fauna. The National Water Carrier (1964), which crosses Israel from north to south, is the 81-mile main artery connecting all regional water projects in the State. (Today in Science History)
19 July 1974...A severe thunderstorm with winds to 80 mph and up to two inches of rain washed out four to five-foot deep sections of roadway in Lake Havasu City, AZ. Three persons in a station wagon died as it was carried 3000 feet down a wash by a ten-foot wall of water. (The Weather Channel)
19 July 1977...Thunderstorms produced torrential rains over parts of southwestern Pennsylvania. Some places in the Johnstown area received more than twelve inches in a seven-hour period. The heavy rains cause flash flooding along streams resulting in widespread severe damage, representing the "second Johnstown flood", second to the more disastrous flood in May 1889. The cloudburst flooded Johnstown with up to ten feet of water resulting in 76 deaths, countless injuries, and 424 million dollars damage. (David Ludlum) (The Weather Channel)
19 July 1994...Hurricane Emilia was the first of three Category-5 hurricanes to develop in the Central Pacific in 1994 as unusually warm sea temperatures prevailed south of Hawaii. Sustained winds reached 160 mph. (Intellicast)
19 July 2006...Charlwood, England melted under the highest temperature ever recorded in Britain in July at 97.3 degrees. (The Weather Doctor)
20 July 1930...The temperature at Washington, DC soared to an all-time record of 106 degrees. The next day Millsboro reached 110 degrees to set a record for the state of Delaware. July 1930 was one of the hottest and driest summers in the U.S., particularly in the Missouri Valley where severe drought conditions developed. Toward the end of the month, state records were set for Kentucky with 114 degrees and Mississippi with 115 degrees. (David Ludlum)
20 July 1934...The temperature at Keokuk, IA soared to 118 degrees to establish an all-time record high temperature for the Hawkeye State. (The Weather Channel)
20 July 1965...The 24-hour maximum precipitation record for the Show-Me State was set at Edgarton, MO as 18.18 inches of rain fell. (NCDC)
20 July 1986...The temperature at Charleston, SC hit 104 degrees for the second day in a row to tie their all-time record high. (The Weather Channel)
20 July 1988...The temperature at Redding, CA soared to an all-time record high of 118 degrees. (The National Weather Summary)
20 July 1989...Showers and thunderstorms in the Middle Atlantic Coast Region soaked Wilmington, DE with 2.28 inches of rain, pushing their total for the period May through July past the previous record of 22.43 inches. Heavy rain over that three-month period virtually wiped out a 16.82-inch deficit that had been building since drought conditions began in 1985. Thunderstorms in central Indiana deluged Lebanon with 6.50 inches of rain in twelve hours. (The National Weather Summary) (Storm Data)
20 July 1994...Seattle-Tacoma, WA sizzled at 100 degrees, the highest ever temperature recorded there. (Intellicast)
20 July 1997...A torrential 32.52 inches of rain fell at Dauphin Island Sea Lab, establishing a 24-hour maximum precipitation record for Alabama. (NCDC)
21 July 1911...The temperature at Painter, WY dipped to 10 degrees to equal the record low for July for the continental U.S. (The Weather Channel)
21 July 1930...The record high temperature for Delaware was set with 110 degrees at Millsboro. (Intellicast)
21 July 1934...The temperature reached 109 degrees at Cincinnati, OH to cap their hottest summer of record. The state record for Ohio was established that day with a reading of 113 degrees near the town of Gallipolis. (David Ludlum)
21 July 1983...The temperature at Vostok, Antarctic (elevation 11,220 ft) fell to 129 degrees below zero, establishing the all-time lowest temperature ever recorded at a surface station on Earth, as well as for the Antarctic continent. (NCDC)
21 July 1991...Windsor Locks, CT hit 101 degrees, the third day in a row with temperatures over 100 degrees. Providence RI reached 102 degrees, their second day of 100-degree readings, very rare for this location. (Intellicast)
22 July 1926...The temperature at Troy, NY reached 108 degrees to set a high temperature record for the Empire State. The record high temperature for Connecticut was set at Waterbury with 105 degrees; this record for the Nutmeg State was broken by one degree in July 1995 at the same city. (Intellicast)
22 July 1972...Fort Ripley, MN received 10.84 inches of rain, to establish a new 24-hour maximum precipitation record for the Gopher State. (NCDC)
22 July 1987...Barrow, AK received 1.38 inches in 24 hours on the 21^st and 22^nd, an all-time record for that location. The previous record was the 1.00-inch water equivalent in a 15-inch all-time record snowfall of 26 October 1926. The average annual precipitation for Barrow is just 4.75 inches. (The National Weather Summary) (The Weather Channel) (Accord's Weather Guide Calendar)

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