WEEKLY CLIMATE NEWS

26-30 July 2021

ITEMS OF INTEREST

• Weather information for the upcoming Tokyo 2020 Olympic and Paralympic Games -- The Tokyo 2020 Olympic and Paralympic Games that have been postponed from 2020 to this summer due to the COVID-19 pandemic will commence this week in Tokyo, Japan. The Olympic Games will run from 23 July through 8 August, while the Paralympic Games are scheduled to run from 24 August 24 through 5 September. The Japan Meteorological Agency (JMA) will provide weather support for the smooth hosting of the Games. This agency has a "Tokyo 2020 Weather Portal" https://www.data.jma.go.jp/tokyo2020/#lang=eng that provides online weather observation data, UV index values, weather maps, satellite images, weather forecasts and other information pertinent to individual event sites in English and Japanese. Since hot and sultry weather is anticipated during the Games that could adversely affect the participants and support personnel, JMA has been working to enhance weather information supporting effective measures against extreme heat; consult the Heat Illness Risk Information https://www.data.jma.go.jp/fcd/yoho/data/kouon/heat_illness.html.
• Peak in the annual temperature curves -- This week represents the third full week of July, which for many locations across the 48 contiguous United States typically are experiencing their warmest week of the year, as indicated by the daily normal high and low temperatures. Usually, those stations located away from the moderating influences of the oceans reach their highest temperatures during the third to fourth week of July, or a roughly one month after the summer solstice, when the Northern Hemisphere receives the most hours of daylight and the highest intensity of solar radiation. During July, temperatures continue to rise to their highest typical values as radiational heating continues. However, the length of daylight and the amount of sunshine during this month begin decrease, as the normal daily temperatures will begin to fall toward their lowest levels in mid to late January. [NOAA Climate.gov News]
  An interactive map is available that provides access to data concerning the highest temperature ever recorded at several thousand stations around the nation (as of Summer 2017) [NOAA Climate.gov History]. Comparison also is invited with the "Warmest Day of the Year" maps generated for the contiguous U.S., along with Alaska, Hawaii and Puerto Rico, by NOAA's National Centers for Environmental Information for the 1981-2010 normals interval.
• Zenithal Sun -- Residents of Hawaii's Big Island are experiencing a noontime sun that would be directly overhead near the end of this week (23-24 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 Hilo and elsewhere on the Big Island. The other time when the Big Island experienced a zenithal sun was in mid-May. [Timeanddate.com]

CURRENT CLIMATE STATUS

• National weather and climate reviewed for June 2021 -- 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 2021. They found:
• The monthly temperature averaged across the coterminous United States for that month was 72.6 degrees Fahrenheit, which was 4.2 Fahrenheit degrees above the 20th-century (1901-2000) June average. Consequently, the nationwide average temperature for this past month was the highest June temperature since 1895 when comprehensive climate records became available nationwide. This June 2021 temperature exceeded the previous June record set in 2016 by 0.9 Fahrenheit degrees. The majority (32) of the 48 contiguous United States reported above to much above-average monthly temperatures for June 2020. Many of the states across the West and along the U.S. Canadian border had statewide temperatures that were in the top ten temperatures on record for the respective state records. Five states across the West (Arizona, California, Idaho, Nevada and Utah) had statewide June average temperatures that were the highest in 127 years of record for their respective states. An additional four Western states (Montana, Oregon, Washington and Wyoming) had average temperatures for June that reached second place. In the Northeast, the June 2921 average statewide temperatures for three states (Massachusetts, New Hampshire and Rhode Island) set records, while two states (Connecticut and Maine) ranked second in the 127 years of record. The remaining 15 states in the "Lower 48" had June temperatures that were near the average for their individual states.
  The maximum (or daytime) temperature for June the 48 contiguous United States was 4.3 Fahrenheit degrees above the 20th century average, which makes this temperature the second highest June reading in the last 127 years. The minimum (nighttime) temperature for the "Lower 48" was 4.0 Fahrenheit degrees above the 20th century average, which was the highest minimum June temperature on record.
  The June 2021 statewide average temperature for Alaska was 51.5 degrees, which is the 20th highest in the state's 97-year period of record that extends back to 1925.
• The nationwide average precipitation for June 2021 was 2.93 inches, which was identical to the 20th-century average; it also ranked as the 59th driest June in 127 years. Nineteen states stretching from the Pacific Northwest eastward across the northern and central Rockies and adjacent Plains States, along with Pennsylvania and New England had statewide precipitation totals that were below to much-below the long-term average. South Dakota had its driest June in 137 years. Conversely, seventeen states running from the Southeast westward to New Mexico and northward over the Mississippi Valley had above- to much-above-average precipitation. Mississippi experienced its second wettest June on record, Alabama its fifth wettest and Michigan its tenth wettest June. The remainder of the states (12) in the "Lower 48" had precipitation totals that were close to the long-term average. These states were scattered across the East, Midwest and West.
  This past June was the 21st wettest in Alaska for the last 97 years, with a statewide June average precipitation of 2.74 inches, which is 0.40 inches above average.
NOTE: A description is provided of the climatological rankings employed by NCEI for their monthly and seasonal maps. [NOAA/NCEI]
• A map entitled "U.S. Selected Significant Climate Anomalies and Events for June 2021" graphically summarizes several significant weather and climate events that occurred across all 50 states and Puerto Rico during June.
[NOAA NCEI State of the Climate]
• June national drought report -- The National Centers for Environmental Information has posted its June 2021 drought report online. Using the Palmer Drought Severity Index, approximately 36 percent of the coterminous United States experienced severe to extreme drought conditions at the end of June, while four percent of the area had severely to extremely wet conditions.
• Sierra snowpack is depleted more rapidly than usual -- A sequence of three natural-color images made from the MODIS instrument onboard NASA's Terra satellite shows the relatively rapid depletion of the snowpack in California's High Sierras this year, beginning on 31 March and ending on 7 July. With a lack of significant winter snowfall across the region, coupled with above average to record high air temperatures through spring and into early summer, the meager snowpack in late March quickly disappeared by early July. The most recent image showed essentially no snow on the mountain peaks from Donner Summit to the west of Lake Tahoe southward to Yosemite, Sequoia and Kings Canyon National Parks to the west and south of Mono Lake. This snowpack is needed for agriculture, public consumption and the maintenance of the region's ecosystem. A comparison can be made of the amount of snowpack on the crest of the Sierras from MODIS satellite images obtained on 12 July 2019, during a wet year, and from 7 July 2021, during an exceptionally dry year. [NASA Earth Observatory]
• Satellites show smoke from Western wildfires blanketing a large area of North America - A 1:32-minute YouTube video shows a variety of animated satellite images of the smoke emanating from the recent wildfires that are burning across the Western states and Canadian provinces during the last several weeks. Winds have been spreading the smoke across a large section of the North American continent. As of this past Wednesday, 68 active large fires were burning in 12 states, consuming vegetation and property across more than one million acres of land in the U.S. Two days earlier, 307 active fires were burning in British Columbia. The fleet of NOAA satellites provides a variety of images and data that can be used to track the smoke and assess air quality. Sensors onboard NOAA's GOES-16 (GOES East) and GOES-17 (GOES West) satellites can help detect and monitor smoke plumes in near-real time, which is particularly useful in directing firefighting efforts from the air. Aerosol optical depth (AOD) data from these two satellites provides an indication of the amount of smoke particles (or aerosols) in the vertical column of atmosphere over a given location, which then can be used in making critical air quality, visibility and aviation forecasts. Suomi NPP and NOAA-20 satellites also provide AOD data, along with information about a fire’s intensity, which is one of the key inputs in NOAA's High-Resolution Rapid Refresh-Smoke forecast model. [NASA NESDIS]
  On 1 July, data obtained from the GOES West satellite was used to show lightning across British Columbia that was produced by the wildfires’ pyrocumulonimbus clouds, or fire-derived clouds created by convection from the fires. In addition to the satellite's Geostationary Lightning Mapper (GLM) overlay, additional GeoColor and Fire Temperature enhancements to the infrared imagery were utilized to produce the animation. [NOAA NESDIS]
• Report made on recurrent high tide coastal flooding across nation during 2019 -- Scientists from NOAA's Center for Operational Oceanographic Products and Services recently prepared a 24-page annual report entitled "2019 State of U.S. High Tide Flooding and a 2020 Outlook" that provides a review of the state of recurrent coastal tidal flooding in the U.S. considered "high tide flooding." This high tide or "nuisance" flooding is defined as a situation when a water level measured at a NOAA water level gauge exceeds the local elevation threshold for minor impacts, which is when tides reach to as much as two feet above the daily average high tide and start spilling onto streets or bubbling up from storm drains. The report indicates that in the 2019 meteorological year running from May 2019 through April 2020, the national annual high tide flooding frequency at 98 NOAA tide gauges (excluding Alaska) reached a median value of four days, which was one day below the historical record of five set in 2015 and in 2018. Nineteen locations along the East and Gulf Coasts either tied or broke their all-time high tide flooding records (median of 13 days) in 2019. Furthermore, the decadal trend of high tide flooding days continues to accelerate, as the median number of days in 2020 was only two. U.S. relative sea levels measured at these stations in 2019 were 1.1 feet above levels measured in 1920. The portion of the report focusing upon the outlook for this 2020 meteorological year ending in April 2021 indicates that the frequency of daily flooding is expected to increase, with many of the nation's coastal communities seeing between two and six days of flooding. Those communities in the Northeast Atlantic and western Gulf Coasts could see five to eleven high tide flooding days, despite anticipated ENSO conditions. Long-term sea level rise trends are a contributing factor. The forecasters envision between seven and fifteen days in high tide flooding by 2030. [NOAA News]

CURRENT CLIMATE MONITORING

• Report made on record high-tide coastal flooding across nation during 2020 -- Scientists from NOAA's Center for Operational Oceanographic Products and Services recently prepared a 28-page annual report entitled "2021 State of U.S. High Tide Flooding and Annual Outlook" that provides a review of the state of recurrent coastal tidal flooding in the U.S. considered "high tide flooding" from May 2020 to April 2021. This high-tide or "nuisance" flooding (HTF) is defined as a situation when a water level measured at a NOAA water level gauge exceeds the local elevation threshold for minor impacts, when tides reach to as much as two feet above the daily average high tide and start spilling onto streets or bubbling up from storm drains. This report indicates that in the 2020 meteorological year running from May 2020 through April 2021, the national annual HTF frequency at 97 NOAA tide gauges (excluding Alaska) had a national median value of four days, which is approximately double the value from 20 years ago and was only one day below the record set two years ago. During 2020, 14 locations along the East and Gulf Coasts either tied or broke their all-time high-tide flooding records for the number of HTF days. Galveston and Corpus Christi in Texas, and Bay Waveland in Mississippi set records of more than 20 days of HTF. La Niña conditions and a record-setting number of land-falling tropical cyclones along the U.S. coast during 2020 contributed to the local record HTF frequency.
  The portion of the recently-released report focusing upon the outlook for this 2021 meteorological year ending in April 2022 indicates that the national HTF frequency of daily flooding is expected to increase, with many of the nation's coastal communities seeing between three and seven days of flooding in the coming year, as compared to between two and six days of flooding that had been projected last year. However, locations along the Atlantic and Gulf coasts may experience even more days of flooding. This projection is based upon anticipated near ENSO-neutral conditions. Long-term sea level rise trends are a contributing factor. The forecasters envision between seven and fifteen HTF days nationally by 2030, rising to 25-75 days by 2050. [NOAA News]

CLIMATE FORECASTS

• New Seasonal (3-month) Climate Outlooks for late 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 August through October 2021, corresponding to the last month of meteorological summer season (in the Northern Hemisphere) and the first two months of meteorological autumn. (September and October). Specific details of their outlooks include:
  • Temperature and precipitation outlooks -- According to their temperature outlook, approximately 85 percent of the 48 contiguous United States should experience a high chance of above average temperatures for these three upcoming months. The forecasters express their highest confidence in their forecasts of a warmer than average next three months for the Northeast extending from New England and New York State southward to the Del-Mar-Va Peninsula, along with sections of the Southwest, centered upon the Great Basin in Utah and Nevada. The lower Mississippi Valley and the southern Plains, stretching from the northern coast of the Gulf of Mexico northward into Missouri could have "Equal Chances" of below-, near-, and above-average temperatures through October. Most of Alaska, with the exception of the southeast Panhandle, was expected to have a warm next three months. Western sections of the 49th State should have the highest chance of above average temperatures through October.
    Their precipitation outlook calls for better than even chances of above-average precipitation for late summer and early autumn of 2021 across a large section of the eastern third of the nation, with the highest probability of above-average precipitation across the Middle Atlantic States and along the Gulf Coast surrounding the mouth of the Mississippi River. Conversely, a large swath of the "Lower 48" to the west of the Mississippi Valley would tend to have a high chance for drier than average conditions over the next three months. The region with the highest probability for the driest late summer and early autumn would be centered over the Four Corners States (Arizona, Colorado, New Mexico and Utah) along with the Great Basin in Nevada. The remainder of the 48 contiguous states should have equal chances of below-, near- and above-average summer precipitation, as no clear-cut climate signal was detected. Eastern sections of Alaska should also have a good chance of wetter than average conditions during these next three months, while western Alaska would have "equal chances" for the three precipitation categories.
    A summary of the prognostic discussion of the 3-month outlook for non-technical users is available from CPC. These forecasts were based upon several factors. Several of the statistical and dynamical forecast models used by CPC forecasters suggest that the current ENSO (El Niño-Southern Oscillation)-neutral conditions could continue for the next three months, before a transition to weak La Niña conditions later in boreal autumn. Current soil moisture conditions also could play a role in this upcoming 3-month temperature outlook. In addition, warm season decadal trends are also considered to be a significant climate signal that is used in making the outlooks. A description is also provided as how to read these 3-class, 3-month Outlook maps.
  • Seasonal Drought Outlook -- The forecasters at NOAA's Climate Prediction Center also released their US Seasonal Drought Outlook last week that would run from late-July through October 2021. Their outlook would call for the persistence of current drought conditions across large areas of the western half of the 48 contiguous U.S. This region currently has severe to exceptional drought that extends northward along the West Coast from central California into the interior Northwest (Oregon and Washington) and eastward across the Great Basin (Nevada and Utah). the Rockies of Colorado to New Mexico. The northern Plains (the Dakotas and eastern Montana) also have been under severe to exceptional drought. (Current drought conditions appear in this past week's US Drought Monitor map.) Expansion and intensification of drought was expected over the next three months in several areas of the West that currently are considered abnormally dry or under moderate drought. On the other hand, several areas currently experiencing moderate drought across the Upper Midwest, the Northeast (New England and Upstate New York) and the southwest (West Texas and southern sections of Arizona and New Mexico) could experience improvement in drought conditions, including their removal from drought status. Note: a Seasonal Drought Outlook Discussion is included describing the forecasters' confidence.

CLIMATE AND SOCIETY

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

• 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)
• 23 July 1923...Sheridan, WY was drenched with 4.41 inches of rain, an all-time 24-hour record for that location. (22^nd-23^rd) (The Weather Channel)
• 23 July 1987...Thunderstorms produced a record ten inches of rain in six and a half-hours at Minneapolis, MN, including 5.26 inches in two hours. Flash flooding claimed two lives and caused 21.3 million dollars damage. Streets in Minneapolis became rushing rivers, parking lots became lakes, and storm sewers spouted like geysers. A tornado hit Maple Grove, MN causing five million dollars damage. Baseball size hail was reported at Olivia, MN. (The National Weather Summary) (Storm Data)
• 23 July 2010...The largest (by diameter) and heaviest hailstone on record in the United States fell on Vivian, SD. The stone was 8 inches in diameter and weighed 1.9 pounds. The person who found the stone reported that some melting had occurred before the official measurement was taken. This hailstone broke the previous US record for diameter (7.0 inches - 22 June 2003 in Aurora, NE) and weight (1.67 pounds - 3 September 1970 in Coffeyville, KS). The Aurora, NE hailstone will retain the record for circumference (18.75 inches). Several other stones of 6 inches or more in diameter were measured during the storm survey. (National Weather Service files)
• 23 July 2011...Chicago, IL set an all-time daily record rainfall when 6.86 inches fell during the early morning hours of Saturday, 23 July 2011, at O'Hare airport. The previous daily record was 6.64 inches set on 13 September 2008. (National Weather Service files)
• 24 July 1928...Wahluke, WA hit a high temperature of 118 degrees, which tied a record high for the state. In August 1961, this all-time state record high was tied at Ice Harbor Dam. (Intellicast)
• 24 July 1936...Record high temperature for Kansas was tied at 121 degrees near Alton. The record high for Nebraska was also tied at Minden with 118 degrees.
• 24 July 1942...The temperature at Las Vegas, NV hit 117 degrees to set an all- time record for that location. (The Weather Channel)
• 24 July 1952...The temperature at Louisville, GA soared to 112 degrees to establish a state record. This record for the Peach State was tied in August 1983. (The Weather Channel) (NCDC)
• 24-25 July 1979...Claudette, a weak tropical storm, deluged southeastern Texas with torrential rains. The Houston suburb of Alvin received 43.00 inches, a 24-hour precipitation record for not only the Lone Star State, but for the U.S. Freeport reported a total of 30 inches. Total damage from flooding was over $400 million. (Intellicast) (David Ludlum) (NCDC) (Accord's Weather Guide Calendar)
• 25 July 1979...Tropical Storm Claudette produced phenomenal rainfall totals in southeast Texas. Thirty to forty inches fell in 24 hours around Alvin. Freeport reported a total of 30 inches. Total damage from flooding was over $400 million. (Intellicast)
• 25 July 1987...Sixteen cities in the eastern U.S. reported record high temperatures for the date. Beckley, WV equaled their all-time record high of 91 degrees, established just the previous day. It marked their fourth day in a row of 90-degree heat, after hitting 90 degrees just twice in the previous 25 years of records. The water temperature of Lake Erie at Buffalo, NY reached 79 degrees, the warmest reading in 52 years of records. (The National Weather Summary)