WEEKLY WEATHER AND CLIMATE NEWS

26-30 November 2018

Items of Interest:

• Second volume of latest national climate assessment report just released -- This past Friday, the U.S. Global Change Research Program that consists of thirteen U.S. government agencies released "Volume II: Impacts, Risks, and Adaptation in the United States" of its 4^th National Climate Assessment (NCA4), which is a Congressionally mandated quadrennial report about how climate change is impacting the United States. This second volume of the NCA4 report follows the Climate Science Special Report, known as "Volume I of the Fourth National Climate Assessment," which was released in November 2017. The just-released second volume of the NCA4 report focuses on the impacts and risks associated with climate change for U.S. sectors (such as agriculture, health, transportation and energy) and regions of the nation. A detailed picture is presented of how communities across the country are already feeling the effects of climate change, together with what impacts U.S. residents could expect if drastic action were not taken to address climate change. Additional discussion and analysis will be forthcoming. [Union of Concerned Scientists Press Release]
• Worldwide GLOBE at Night 2018 Campaign for December commences -- The twelfth in a series of GLOBE at Night citizen-science campaigns for 2018 will commence this Thursday (29 November) and continue through Saturday, 8 December. GLOBE at Night is a worldwide, hands-on science and education program designed to encourage citizen-scientists worldwide to record the brightness of their night sky by matching the appearance of a constellation with the seven magnitude/star charts of progressively fainter stars. These constellations are Perseus in the Northern Hemisphere and Grus for the Southern Hemisphere. Activity guides are also available. The GLOBE at night program is intended to raise public awareness of the impact of light pollution. The first series in the 2019 campaign is scheduled for 29 December-7 January 2019. [GLOBE at Night]
• Beginning of meteorological winter season -- The winter meteorological season in the Northern Hemisphere starts on Saturday (1 December). Recall that climatologists and meteorologists have elected to use a standard three-month grouping to identify each meteorological season. Hence, the months of December, January and February are considered the winter meteorological season. You will note that the winter solstice, marking the day where the length of daylight is least in the Northern Hemisphere is still three weeks away, falling on Friday, 21 December 2018. Since the lowest temperatures typically fall in mid to late January, the meteorological winter tends to be centered on the coldest time of the year in the Northern Hemisphere.
  In addition, Friday (30 November) marks the end of the official 2018 hurricane seasons in the North Atlantic, which includes the Gulf of Mexico and the Caribbean, along with the eastern and central North Pacific basins.
• The 2018 hurricane seasons reviewed -- With the end of the official 2018 hurricane season in both the North Atlantic and North Pacific on Friday (30 November 2018), a quick review of this year's tropical cyclone statistics for the official 2018 hurricane season has been made for both basins. [AMS DataStreme Atmosphere]
  For those who are interested in obtaining historic hurricane information, the "Historical Hurricanes Mapping & Analysis Tool" developed by NOAA allows the search and display of detailed data for more than 6000 tropical cyclones in seven of the planet's major ocean basins based upon a data set that runs from 1842 to 2017. Coastal population trends are also available for the Atlantic and Gulf Coasts of the United States.
• High-quality maps of December 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 December 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.
• December 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 December, 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.
• It's Sure Dark! -- Have you noticed that the sun is setting early these days? During the first ten days of December, many locations throughout the country will experience their earliest sunset times of the year. The exact day for the earliest sunset depends upon the latitude, so you may want to check the date in your locale from the sunrise tables appearing in an on-line, interactive service available for the entire year at most cities in the United States. The reason for the earliest sunsets occurring in early December rather than on the winter solstice (during the evening hours of Friday, 21 December 2018) is that the sun is not as precise a timekeeper as our watches. Because of a combination of factors involved with Earth's elliptical orbit about the sun and the tilt of Earth's spin axis with respect to the plane of the ecliptic, the sun appears to "run fast" by as much as 15 minutes as compared with clock time in November. However, with the approach of the winter solstice and perihelion (the smallest earth-sun distance during late night hours of 2 January 2019), the apparent sun slows during December and finally lags the clock by 12 minutes in February. Consequently, a noticeable and welcome trend toward later sunsets can be detected by the end of December, especially by those residents in the northern part of the country. However, the latest sunrises occur at most locales in early January, meaning that early risers will continue seeing dark and dreary mornings for another month.
• "Coldest day of the year" is on the horizon -- NOAA's National Centers for Environmental Information (NCEI) produced a set of "Coldest Day of the Year" maps for the contiguous United States, Alaska, Hawaii and Puerto Rico showing the dates of the lowest daily minimum temperatures of the year as calculated from the 1981-2010 climate normals. Many places across the West will experience their lowest daily temperatures starting during the next two to three weeks in early December. On the other hand, some areas across the West will not reach their lowest daily temperatures of the year until late January. [NOAA NCEI News]
  [Notes: (1.) According to the seasonal variations in the long-term average or "normal" temperatures, many locations across the nation not along the coasts typically have their lowest normal daily high and low temperatures during the third week of January, nearly one month after the winter solstice. However, areas across the West have their lowest temperatures during the month of December, with elevation becoming an influence.
  (2.) For comparison purposes, check the corresponding NCEI map for the "Warmest Day of the Year" that shows the dates of occurrence of the highest maximum temperatures. EJH]
• First snow of season histories are available for several thousand US weather stations -- NOAA's National Centers for Environmental Information has assembled an interactive map that allows the user to obtain the dates of the first measurable snowfall (0.1 inches or more) for several thousand weather stations across the United States (including Alaska) in the Global Historical Climatology Network that have at least 20 years of record. Clicking on a station location will provide not only the date of the first observed snowfall at that location, but the amount of this first snow and the first year of observation for that station. [NOAA Climate.gov News]
• SKYWARN™ recognition -- This Saturday 1 December 2018 (starting at 00Z or 7:00 EST PM on Friday night) has been declared SKYWARN™ Recognition Day, a day in which the National Weather Service and the American Radio Relay League celebrate the contributions made by volunteer SKYWARN™ radio operators during the past year's Severe Weather Operations.
• NOAA Tide Tables for 2019 are available -- NOAA's National Ocean Service has announced that the 2019 NOAA Tide Tables and Tidal Current Tables are now available. These annual tide predictions and tidal current predictions, which represent the 153rd edition, can be obtained online for US coastal stations; printed tide tables are also available. [NOAA National Ocean Service News]
  Three years ago, a narrative along with a timeline visualization of the evolution of the NOAA Tide Tables since the first tide tables for locations along the East Coast of the United States when first published by the US Coast Survey in 1853. The changes in the methods used to compute the tide tables over the last 150 years are also described. [NOAA National Ocean Service News]

Weather and Climate News Items:

• Eye on the tropics --- Several tropical cyclones were reported during the last week over the tropical waters of both the Northern and Southern Hemispheres:
  • In the North Indian Ocean basin:
    Tropical Cyclone Gaja had weakened to a tropical depression at the start of last week as it traveled across the Arabian Sea after passing over southern India over the previous weekend. At the time Gaja was heading toward the west-northwest approximately 910 miles to the southeast of Masirah Island, Oman. Satellite imagery and additional information on Cyclone Gaja can be found on the NASA Hurricane Blog.
  • The former Tropical Storm Bouchra, which had weakened to a post-tropical cyclone northwest of Cocos Island, Australia during the previous week, was seen to reform over last weekend. At the beginning of this past week, the reborn Bouchra was traveling toward the southwest as it was located nearly 800 miles to the southeast of Diego Garcia. After several days, the new Bouchra was torn apart by wind shear and ultimately disspated by midweek approximately 700 miles to the southeast of Diego Garcia. Satellite images and additional information on Tropical Cyclone Bouchrahe can be found on the NASA Hurricane Blog.
• In the western North Pacific basin:
  
  • The remnants of Tropical Storm Toraji traveled across southern sections of Vietnam on the Indochina Peninsula at the beginning of last week and then exited out over the Gulf of Thailand. These remnants intensified to become a tropical depression that eventually weakened during the second half of this past week approximately 400 miles to the west-southwest of Ho Chi Minh City, Vietnam. The NASA Hurricane Blog had additional information and a satellite image for Tropical Depression Toraji as it was over the Gulf of Thailand.
  • Tropical Depression 33W (TD-33W), had developed at the start of last week over the waters of the Philippine Sea approximately 600 miles to the east of the southern Philippine island of Mindanao. By early Monday, TD-33W was 900 miles to the east-southeast of Manila, Philippines. Traveling toward the west-northwest, TD-33W was expected to strengthen to become a tropical storm as it heads toward the southern Philippine Islands.
    NASA Hurricane Blog https://blogs.nasa.gov/hurricanes/tag/33w-2018/
    Tropical Storm 33W (Usagi)
    NASA Hurricane Blog https://blogs.nasa.gov/hurricanes/tag/man-yi-2018/
    
    https://blogs.nasa.gov/hurricanes/tag/toraji-2018/