WEEKLY CLIMATE NEWS

25-29 June 2018

ITEMS OF INTEREST

• Lightning Awareness Week -- The National Lightning Safety Council will celebrate the annual National Lightning Safety Awareness Week during this upcoming week, 24 through 30 June 2018. Check for specific topics that will be featured each day. According to NOAA's National Weather Service (NWS), an average of 47 people across the nation are killed annual by lightning and numerous more are injured. NWS has a "Lightning Safety" website that has links to a variety of informational and teacher resource materials. Several states are also observing this week with statewide activities, including Colorado. [National Lightning Safety Council]
• 'Tis the season for "night shining clouds" -- The United Kingdom's BBC Weather Centre recently produced a one-minute video of noctilucent (night shining) clouds, the highest clouds in the Earth's atmosphere, often found at altitudes of approximately 50 miles. The video was produced by a group of weather watchers in the British Isles who observed these clouds at the start of last week. These clouds, which consist of ice crystals, are sometimes visible during astronomical twilight (or an hour or two after sunset) during the summer months. They appear similar to bluish, very high cirrus clouds. [BBC Weather Centre]
• Change in seasons -- The beginning of July (Sunday, 1 July 2018) marks the beginning of the new heating season. Traditionally, meteorologists and climatologists define the heating season to run from 1 July to 30 June of the following year. Heating degree day units are accumulated commencing on 1 July. Likewise, the snow season runs from 1 July through 30 June. Seasonal snowfall totals for next season at U.S. stations will be summed from Sunday.

CURRENT CLIMATE STATUS

• Rainy conditions across Southeast in May leads to reduced diurnal temperature range -- Derek Arndt, Chief of the Climate Monitoring Branch at NOAA's NCEI, posted a blog on the "Beyond the Data" site in which he explained how the soggy weather conditions in May 2018 across sections of the Southeast -- in particular, Florida -- resulted in a smaller Diurnal Temperature Range (DTR) than usual. Rain-producing clouds during the daytime acted as sunshades to cause the maximum daytime temperatures to run below average, while the nighttime clouds and increased atmospheric water vapor helped keep nighttime minimum temperatures elevated because of the greenhouse effect. The lower maximum temperatures and higher minimum temperatures resulted in a reduced DTR in May 2018 (which represents the arithmetic difference between the day's maximum and minimum temperatures). [NOAA Climate.gov News]
• Assessing the development of recent wildfires across southwestern Colorado -- An "Event Tracker" blog was posted on the ClimateWatch Magazine by a meteorologist from NOAA's Climate Prediction Center that discusses the development of the large wildfires across the San Juan National Forest and adjacent areas in southwestern Colorado during the month of June. These wildfires had developed because of the exceptional drought that has persisted during the last two months across the southern Colorado forests. The wildfire climatology of the Four Corners area (Arizona, Colorado, New Mexico and Utah) was addressed, which typically peaks in early July, as rain spreads across the region in association with the annual return of the North American Monsoon. Finally, the number of large wildfires in the western United States has been found to be increasing over the last thirty years, attributed in part to a changing climate. This trend is projected to continue through the second half of the 21st century in association with increased temperatures due to continued increases in carbon dioxide emissions. [NOAA News]

CURRENT CLIMATE MONITORING

• Review of global weather and climate for May 2018 -- Scientists at NOAA's National Centers for Environmental Information (NCEI) report that the recently concluded month of May was the fourth warmest May since sufficiently dense global climate records began in 1880. They based their report on preliminary calculations of the combined global land and ocean surface temperature for May 2018, which was 1.44 Fahrenheit degrees (0.80 Celsius degrees) above the 20th century's (1901-2000) average May temperature of 58.6 degrees Fahrenheit. This global temperature lagged behind temperatures for the month of May in 2016, 2015 and 2017. When considered separately, the global ocean surface temperature for May 2018 was 1.19 Fahrenheit degrees above the 20th century average, making last month's sea surface temperature the fourth highest May temperature since 1880. The average May 2018 land surface temperature was 2.05 Fahrenheit degrees above the 20th century average, which meant that this land surface temperature tied May 2013 for the seventh highest May land temperature in the 139-year period of record.
  In addition, the combined global land and ocean surface temperature for the last three months (March through May), which is considered meteorological spring in the Northern Hemisphere (fall in the Southern Hemisphere), was 1.48 Fahrenheit degrees above the 20th century average, or the fourth highest temperature since 1880.
  The May 2018 sea ice extent data for the Arctic Ocean was the second smallest May sea ice extent since satellite records began in 1979, following behind the record smallest extent in May 2016. The sea ice cover on the waters around Antarctica in May was the third smallest May extent since 1980.
  According to data from the Rutgers Global Snow Lab, the Northern Hemisphere snow cover extent for May was the 37th largest in the 52-year period of record.
  [NOAA/NCEI State of the Climate]
  A global map of Selected Significant Climate Anomalies and Events for May 2018 is available from NCEI.
• An international oceanography satellite reaches tenth anniversary at tracking sea level rise -- During this past week, the joint U.S./European Ocean Surface Topography Mission (OSTM) on the Jason-2 satellite marked its tenth anniversary, having made more than 47,000 orbits of Earth as it measures sea level change across the globe, observes ocean currents, studies climate phenomena such as El El Niño and La  Niña, and monitors the long-term rise in global mean sea level. The Jason-2 satellite has been joined by Jason-3 in early 2016, resulting in a slightly different science mission for the earlier satellite that entails collecting data along a series of very closely spaced ground tracks from a slightly lower orbit. [NASA Global Climate Change News]

CLIMATE FORCING

• A built-in "speed bump" may offer protection for hurricanes during active Atlantic hurricane eras -- A contractor with NOAA's Climate Program Office describes the apparent built-in speed bump that exists during active hurricane eras, saving the U.S. coast from some of the approaching major hurricanes. A NOAA scientist has constructed maps of the tropical Atlantic, the Caribbean and Gulf of Mexico that show the differences in vertical wind shear and sea surface temperature between the current active hurricane era (1993-2015) and the previous quiet period (1970-1992). During the current active hurricane era, the sea surface temperatures across the main hurricane development region in the eastern Atlantic were above average, while the vertical wind shear was relatively weak. Consequently, hurricane formation was favored. However, the waters over the Gulf of Mexico and off the U.S. Southeastern coast were cooler than average during the current active period, along with a stronger wind shear. Such a situation would not be favorable for hurricane development. [NOAA Climate.gov News]

CLIMATE FORECASTS

• New Seasonal Climate Outlooks for this summer and early fall issued -- Near the end of last week, forecasters at the NOAA Climate Prediction Center (CPC) released their new national Three-Month (Seasonal) Climate Outlooks for July through September 2018, corresponding to the last two months of the meteorological summer season (in the Northern Hemisphere) and the first month of meteorological autumn. Specific details of their outlooks include:
  • Temperature and precipitation outlooks -- According to their temperature outlook, slightly more than 85 percent of the contiguous United States along with Alaska should experience a high chance of above average temperatures for these three upcoming months. The interior Northwest, centered over Oregon and Nevada, and the Northeast, centered on New York State and New England, appear to have the greatest chance for having above average temperatures. Only sections of the Upper Midwest and the northern Plains could have nearly equal chances of warmer or cooler than normal conditions. The greatest probability for above average temperatures in Alaska would be found along coastal sections of the 49th state that include the Aleutian Islands and the Panhandle.
    CPC's precipitation outlook calls for better than even chances of wet conditions for the summer and early autumn of 2018 across the sections of the Southwest, centered on the Four Corners States (Arizona, Colorado, New Mexico and Utah) and the Middle Atlantic States, centered upon Maryland, Virginia and West Virginia. Drier than average conditions for the next three months were anticipated across the Northwest, centered upon Washington and northern Idaho, as well as across the western Gulf Coast and lower Mississippi Valley, centered upon the Texas and Louisiana Gulf Coasts. The rest of the 48 contiguous states should have equal chances of below and above average summer-early fall precipitation. Most of Alaska, with the exception of the southeast Panhandle, should have a good chance of above average precipitation. The Panhandle should have equal chances of below or above average precipitation through the first month of autumn.
    A summary of the prognostic discussion of the 3-month outlook for non-technical users is available from CPC. These forecasts were based upon the increasing chances for the development of an El Niño by the onset of meteorological autumn (in the Northern Hemisphere). A description is also provided as how to read these 3-class, 3-month Outlook maps.
  • Seasonal Drought Outlook released -- The forecasters at NOAA's Climate Prediction Center also released their US Seasonal Drought Outlook last week that would run from late-June through September 2018. Their outlook would call for persistence of drought conditions across many sections of regions currently experiencing drought conditions, especially in southern California, Nevada and Oregon in the West, Texas in the southern Plains and the Dakotas and Montana in the northern Plains. However, anticipated above average precipitation across the Four Corners States (Arizona, Colorado, New Mexico and Utah) should result in an amelioration of drought conditions across the Intermountain West. Scattered areas of the southern and central Plains along with the lower Missouri Valley could see improvement in drought conditions, with possible removal from drought status. Drought conditions were expected to intensify across central Texas and across New York State and New England. Note: a Seasonal Drought Outlook Discussion is included describing the forecasters' confidence.
• An updated El Niño forecast from Down Under -- Forecasters with the Australian Bureau of Meteorology recently issued an updated ENSO Outlook, in which they reported that although ENSO-neutral conditions were continuing, the warming in the tropical Pacific Ocean and the some of the latest computer model outlooks indicate development of El Niño conditions during Southern Hemisphere spring (September through November). Therefore, the Australian forecasters have moved the Bureau's ENSO Outlook status to an El Niño WATCH, meaning the likelihood of an El Niño forming in 2018 would be at least 50 percent, or double the normal chance. [Australian Government Bureau of Meteorology]

CLIMATE AND THE BIOSPHERE

• Assessing the development of recent wildfires across southwestern Colorado -- An "Event Tracker" blog was posted on the ClimateWatch Magazine by a meteorologist from NOAA's Climate Prediction Center that discusses the development of the large wildfires across the San Juan National Forest and adjacent areas in southwestern Colorado during the month of June. These wildfires had developed because of the exceptional drought that has persisted during the last two months across the southern Colorado forests. The wildfire climatology of the Four Corners area (Arizona, Colorado, New Mexico and Utah) was addressed, which typically peaks in early July, as rain spreads across the region in association with the annual return of the North American Monsoon. Finally, the number of large wildfires in the western United States has been found to be increasing over the last thirty years, attributed in part to a changing climate. This trend is projected to continue through the second half of the 21st century in association with increased temperatures due to continued increases in carbon dioxide emissions. [NOAA News]
• New instrument will detect plant water use from space -- A new instrument called ECOSTRESS, or ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station, is expected to be installed within the next week on the International Space Station to detect the water use by plants from a space perspective. ECOSTRESS, which was built by NASA'S Jet Propulsion Laboratory, will measure the temperature of plants, enabling researchers to determine plant water use through transpiration and to study how drought conditions affect plant health. [NASA Global Climate Change News]

CLIMATE AND SOCIETY

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

• 25 June 1925...The mercury hit 101 degrees at Portland, OR, their earliest 100-degree reading of record. (Sandra and TI Richard Sanders)
• 25 June 1953...The temperature at Anchorage, AK soared to 86 degrees, their highest reading of record. (The Weather Channel)
• 25 June 1988...Fifty-two cities in the central and eastern U.S. reported record high temperatures for the date. Highs of 100 degrees at Erie, PA and 104 degrees at Cleveland, OH established all- time records for those two locations. Highs of 101 degrees at Flint, MI, 105 degrees at Chicago, IL, and 106 degrees at Fort Wayne, IN equaled all-time records. (The National Weather Summary) (Storm Data)
  Southwestern Ontario experienced a heat wave as the mercury soared to 104.4 degrees in Windsor and 100.8 degrees in London, the hottest day ever recorded in these cities. (The Weather Doctor)
• 26 June 1931...The temperature soared to 92 degrees at Anchorage, AK, the highest reading of record to date for that city. (The Weather Doctor)
• 27 June 1915...The temperature at Fort Yukon, AK soared to 100 degrees to establish a state record. (The Weather Channel)
• 27 June 1988...The afternoon high of 107 degrees at Bismarck, ND was a record for the month of June, and Pensacola, FL equaled their June record with a reading of 101 degrees. Temperatures in the Great Lakes Region and the Ohio Valley dipped into the 40s. (The National Weather Summary)
• 27 June 1994...The temperature reached 122 degrees at the Waste Isolation Treatment Plant east of Carlsbad, NM to set the state high temperature record for New Mexico. In Oklahoma, the temperature at the mesonet station near Tipton reached 120 degrees, setting an all-time record for the Sooner State. (NCDC) (Accord's Weather Guide Calendar)
• 28 June 1892...The temperature at Orogrande, UT soared to 116 degrees to establish a record for the Beehive State. This record was broken by one degree in July 1985. (Sandra and TI Richard Sanders)
• 28 June 1954...The temperature at Camden, SC reached 111 degrees to establish an all-time high temperature record for the Palmetto State. (NCDC)
• 28 June 1960...The maximum 24-hour precipitation record for the Bluegrass State was established at Dunmor, KY when 10.40 inches fell. (NCDC)
• 28 June 1976...Temperature reached 96 degrees in Southampton, England's Mayflower Park for the highest temperature ever in June in England. (The Weather Doctor)
• 28 June 1980...The temperature at Wichita Falls, TX soared to 117 degrees, their highest reading of record. Daily highs were 110 degrees or above between the 24^th of June and the 3^rd of July. (The Weather Channel)
• 28 June 1994...Laughlin, NV reached 125 degrees, the state's all-time record high temperature. (Intellicast) The temperature at Monahans, TX reached 120 degrees to set a new high temperature record for the Lone Star State. (NCDC)
• 29 June 1931...The temperature at Monticello, FL hit 109 degrees to establish an all-time record for the Sunshine State. (The Weather Channel)
• 29 June 1975...Litchville recorded 8.10 inches of rain for North Dakota's state 24-hour precipitation record. (NCDC)
• 29 June 1988...Jackson, MS equaled their record for the month of June with an afternoon high of 105 degrees. (The National Weather Summary)
• 29 June 1994...The mercury hit a scorching 128 degrees at Lake Havasu City, AZ to set a new all-time record high temperature for the Grand Canyon State. This reading also tied the one at Death Valley, CA on the same day for the US June record. The previous state record for Arizona was 127 degrees set at Parker on 7 July 1905. The temperature at Laughlin, NV reached 125 degrees, which also set an all-time record high temperature for the Silver State. (NCDC) (Accord's Weather Guide Calendar) (The Weather Doctor)
  The lowest temperature ever recorded in Australia: was a 9.4-degree below zero reading at Charlotte Pass, New South Wales, Australia. (The Weather Doctor)
• 30 June 1912...The deadliest tornado in Canadian history struck Regina, Saskatchewan, as 28 people were killed. (The Weather Doctor)
• 30 June 1983...Tasmania's coldest night on record was observed as the temperature at Shannon dropped to 8.6 degrees. (The Weather Doctor)
• 30 June 1989...The remains of tropical storm Allison dropped copious amounts of rain on Louisiana. Winnfield, LA reported 22.52 inches of rain in three days, and more than thirty inches for the month, a record for June. Shreveport received a record 17.11 inches in June, with a total for the first six months of the year of 45.55 inches. Thunderstorms also helped produce record rainfall totals for the month of June of 13.12 inches at Birmingham, AL, 14.66 inches at Oklahoma City, OK, 17.41 inches at Tallahassee, FL, 9.97 inches at Lynchburg, VA, and more than 10.25 inches at Pittsburgh, PA. Pittsburgh had also experienced a record wet month of May. (The National Weather Summary) (Intellicast)
• 30 June 1999...Mount Baker, Washington closed out a record snowfall season both for the United States and the verifiable world record as the seasonal total from 1 July 1998 to 30 June 1999 finished with 1,140 inches. (National Weather Service files)
  
• Month of July 1861...The greatest one-month of precipitation ever measured globally (366 inches) was recorded at Cherrapunji, India. Total rainfall for the period 1 August 1860 to 31 July 1861 was the greatest rainfall in one year ever recorded (1041.78 inches). (The Weather Doctor)
• Month of July 1931...The July- August 1931 flood in the Yangtze basin of China affected over 51 million people or one-quarter of China's population. As many as 3.7 million people perished from this great 20^th century disaster due to disease, starvation or drowning. (The Weather Doctor)
• 1 July 1911...The high temperature of just 79 degrees at Phoenix, AZ was their lowest daily maximum of record for the month of July. The normal daily high for 1 July is 105 degrees. (The Weather Channel)
• 1 July 1915...Pawtucket, RI received a deluge with 5.1 inches of rain in 24 hours. (Intellicast)
• 1 July 1931...The summer flood along the Yangtze River during July and August 1931 was the most severe in history, with over 51 million Chinese affected. 3.7 million people perished from this greatest disaster of the century due to disease, starvation or drowning. This flood was preceded by a prolonged drought in China during the 1928-1930 period. (National Weather Service files)
• 1 July 1979...Nearly half a foot (5.8 inches) of snow fell at Stampede Pass, WA, a July record. (The Weather Channel)
• 1 July 1988...Twenty-six cities in the north central and northeastern U.S. reported record low temperatures for the date --an unusual cool spell in what turned out to be one of the hottest summers on record. Lows of 48 degrees at Providence, RI, 48 degrees at Roanoke, VA, 49 degrees at Stratford, CT, and 48 degrees at Wilmington, DE, were records for the month of July. Boston, MA equaled their record for July with a low of 50 degrees. Barre Falls, MA dropped to 34 degrees. Five inches of snow whitened Mount Washington, NH. (The National Weather Summary) (Intellicast)
• 1 July 1987...Lake Charles, LA was drenched with a month's worth of rain during the early morning. More than five inches of rain soaked the city, including 2.68 inches in one hour. (The National Weather Summary)

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Prepared by Edward J. Hopkins, Ph.D., email hopkins@aos.wisc.edu
© Copyright, 2018, The American Meteorological Society.