WEEKLY WEATHER AND CLIMATE NEWS

15-19 October 2018

Items of Interest:

• An explanation of the term "water year" -- Two weeks ago (on Monday, 1 October 2018) marked the start of water year 2019. The term "water year" or hydrological year has been used nearly a century by hydrologists dealing with surface water supply such as streamflow and other hydrological data. As a matter of convenience, the beginning of this twelve-month period is meant to begin and end during a relatively dry season. In the United States, as well as in other nations in the Northern Hemisphere, the start of the water year on 1 October corresponds to when the season of soil moisture recharge commences as precipitation begins to exceed losses due to evapotranspiration. [AMS Glossary of Meteorology]
• NASA's Terra satellite reaches a milestone -- On Saturday, 6 October 2018, NASA's Terra satellite had completed 100,000 orbits around planet Earth after being launched on 18 December 1999. The Terra satellite, which is an orbit approximately 400 miles above the Earth's surface, has five onboard scientific instruments that provide observations of the planet: The Advanced Spaceborne Thermal Emission and Reflection (ASTER) instrument; the Moderate Imaging Spectroradiometer (MODIS); Multi-angle Imaging Spectroradiometer (MISR); Measurements of Pollution in the Troposphere (MOPITT); and the Clouds and Earth's Radiant Energy System (CERES). [NASA Goddard Space Flight Center Feature]
• Hurricane Michael was a historic hurricane on several counts -- This past Wednesday, Hurricane Michael made landfall as an unprecedented high-end Category 4 hurricane (on the Saffir-Simpson Scale) along the Florida Panhandle region with a preliminary estimated maximum sustained wind speed of 155 mph at landfall and a minimum air pressure of 919 mb (27.14 inches of mercury).
  In terms of central barometric pressure, Michael was the third most powerful hurricane to strike the U.S. mainland, ranked behind the unnamed Labor Day Hurricane of September 1935 (892 mb) and Hurricane Camille (900 mb) in August 1969. However, Michael's central pressure was the lowest on record for any October hurricane to strike the United States.
  In terms of maximum sustained wind speed at landfall, Michael was the fourth strongest, behind the Labor Day 1935 hurricane (184 mph), Hurricane Camille (172 mph) and Hurricane Andrew in 1992 (167 mph). Michael is the first Category 4 hurricane on record to make landfall on the Florida Panhandle. [National Weather Service Tallahassee (FL) Office] [Washington Post]
• Celebrate Earth Science Week 2018 -- The National Oceanic and Atmospheric Administration, including the National Weather Service, along with NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute have recognized this week (14-20 October 2018) as Earth Science Week 2018 to help the public gain a better understanding and appreciation for the earth sciences and to encourage stewardship of the Earth. This year's theme for the 21th annual Earth Science Week is “Earth as Inspiration” that is designed to "emphasize artistic expression as a unique, powerful opportunity for geoscience education and understanding in the 21st century." [American Geological Institute]
• Observe Earth Observation Day -- On Tuesday 16 October 2018, Earth Observation Day (EOD) will be observed as a celebration of the NASA/USGS (US Geological Survey) Landsat mission. EOD is a Science, Technology, Engineering, and Mathematics (STEM) educational outreach event sponsored by AmericaView, a nationwide, university-based, and state-implemented consortium, and its partners. The goal of EOD is to engage students and teachers in remote sensing as an exciting and powerful educational tool. Lesson plans and educational resources for educators and students are available from the EOD website. [AmericaView]
• Winter Weather Awareness -- Colorado will be observing Winter Weather Awareness Week during this coming week (14-20 October 2018). Residents of Colorado should become aware of the hazards associated with winter storms and other cold weather events by reviewing the material prepared by the local National Weather Service Office. Other states will be observing their own winter weather awareness events during subsequent weeks. Stay tuned for further announcements.
• Autumn severe weather awareness - Since autumn represents a secondary season for severe weather across sections of the Mid-South, Alabama will observe Fall Severe Weather Awareness Day on Wednesday, 17 October 2018. Residents of Alabama, along with their neighbors in adjacent states, should become aware of the hazards associated with severe weather events by reviewing the material prepared by the local National Weather Service Office.
• International ShakeOut Day -- This Thursday, 18 October 2018, has been designated International ShakeOut Day, in which people and organizations around the world are encouraged to practice "Drop, Cover, and Hold On" to reduce injury and death during earthquakes. Some coastal states including California and Washington are providing information on how to evacuate, survive and recover from tsunamis that could be generated along the coast by the earthquakes.

Weather and Climate News Items:

• Eye on the tropics -- Tropical cyclone activity was reported last week in the Atlantic, eastern Pacific and Indian Ocean basins of the Northern Hemisphere:
• In the North Atlantic Basin (that also includes the Caribbean Sea and Gulf of Mexico):
  • Tropical Storm Michael continued to strengthen rapidly at the start of last week as it traveled northward from the western Caribbean and through the Yucatan Channel. By sunrise last Monday morning, Michael was a high-end tropical storm that was headed to the north and was approximately 70 miles to south of the western tip of Cuba. By late Monday morning, Michael had become the seventh Atlantic hurricane of 2018 as maximum sustained surface winds reached 75 mph. Continuing toward the north and then north-northwest across the Gulf of Mexico on Monday and Tuesday, Michael became a major category 3 hurricane (on the Saffir-Simpson Scale) late Tuesday afternoon as its central eye was 470 miles to the south of Panama City, FL. At this time, maximum sustained surface winds were determined to be 120 mph, making Michael the second major hurricane of the 2018 Atlantic hurricane season. By early Wednesday morning, Air Force Reserve and NOAA Hurricane Hunter aircraft had collected data indicating that maximum sustained winds have increased to 130 mph with higher gusts, meaning that Michael had become an extremely dangerous category 4 hurricane as it continued to head to the north toward the Florida Panhandle. Michael continued to strengthen as it took a track toward the north-northeast, making landfall early Wednesday afternoon near Mexico Beach, FL with maximum sustained winds determined to be 155 mph, just shy of the 157-mph threshold for category 5 hurricanes. At that time, the minimum central pressure was 919 mb. The hurricane-force winds, the life-threatening storm surge and the torrential rains that accompanied Hurricane Michael caused widespread and extensive damage to the Florida Panhandle, especially from Panama City Beach eastward to past Apalachicola. After making landfall, Michael traveled toward the northeast across the Florida Panhandle and southern Georgia as a hurricane before weakening to a tropical storm early Thursday morning as its center was approximately 30 miles to the south-southwest of Macon, GA. Continuing to the northeast, this tropical storm traveled across eastern Georgia, and the Carolinas on Thursday. By early Friday morning, Michael was losing its tropical characteristics as it crossed southeastern Virginia and moved out over the waters of the North Atlantic offshore of Norfolk, VA. Michael began re-strengthening as it became an extratropical cyclone during the morning. Consult the NASA Hurricane Blog Page for more information and satellite images on Hurricane Michael. As of last Friday, damage estimates in the United States were believed to have exceeded $8 billion. At least 18 were killed in Florida, Georgia, North Carolina and Virginia because of Hurricane Michael.
  • Tropical Storm Leslie, which had reached hurricane status during the week before last, was traveling to the east-southeast across the central North Atlantic at the start of this past week. As of last Monday morning, Leslie was located nearly 1000 miles to the east-southeast of Bermuda. Leslie continued to strengthen as it traveled toward the southeast on Tuesday, becoming a hurricane for a second time by early Wednesday morning as it was located approximately 1070 miles to the east-southeast of the Azores. After traveling toward the south-southeast on Wednesday, Leslie turned toward the east-northeast by early Thursday. On Friday, Hurricane Leslie passed to the south of the Azores and near the Madeira Archipelago. Continuing to head toward the east-northeast, Leslie began weakening on Saturday, as it approached the Iberian Peninsula as a minimal hurricane. However, before making landfall on Saturday evening, Leslie had lost its tropical characteristics, transitioning into a strong extratropical cyclone approximately 120 miles to the west-northwest of Lisbon, Portugal. Strong winds, high surf and torrential rain accompanying Leslie spread across the Iberian Peninsula over this past weekend. The NASA Hurricane Blog Page has satellite images and additional information on Hurricane Leslie.
  • A tropical depression formed on Tuesday morning approximately 475 miles to the southwest of the southernmost of the Cabo Verde Islands. Traveling toward the west-northwest, this tropical depression became Tropical Storm Nadine on Tuesday afternoon, the fourteenth named tropical cyclone of 2018 in the Atlantic basin. Nadine strengthened as it traveled generally toward the northwest over the next day, reaching maximum strength by Wednesday afternoon and evening as this small tropical storm was at least 600 miles to the west of the Cabo Verde Islands. Continuing toward the northwest and then west-northwest, Nadine began weakening and becoming disorganized on Thursday. During the predawn hours of Friday morning, became a remnant low as it was approximately 1000 miles to the west of the southernmost Cabo Verde Islands. Additional information and satellite images for Tropical Storm Nadine are available on the NASA Hurricane Blog Page.
• In the eastern North Pacific basin (east of the 140-degree West meridian of longitude):
  • Hurricane Sergio was drifting across the waters of the eastern Pacific last Monday morning, approximately 1300 miles to the west-southwest of Cabo San Lucas at the southern tip of Mexico's Baja California Peninsula. After accelerating toward the northeast, Sergio weakened to a tropical storm on Tuesday afternoon. Over the next two days, Sergio continued on a track toward the northeast. Early Friday morning, Tropical Storm Sergio made landfall along the coast of Mexico's Baja California Sur, approximately 125 miles to the southwest of Santa Rosalia, Mexico. Traveling to the northeast across the Baja California Peninsula, Sergio weakened rapidly. Tropical Storm Sergio moved out over the Sea of Cortez on Friday morning, before weakening into a tropical depression during the midday hours. As of Friday afternoon, Tropical Depression Sergio had degenerated into a remnant low over northwestern Mexico, approximately 100 miles to the northeast of Guaymas, in the Mexican state of Sonora. Locally heavy rains accompanying Sergio spread across northwestern Mexico, as well as into Arizona and New Mexico. The NASA Hurricane Blog Page has additional information and satellite images on Hurricane Sergio.
  • Tropical depression 22-E (TD-22E) formed on Sunday morning off the coast of southwestern Mexico, approximately 170 miles to the southeast of Manzanillo, Mexico. Although this tropical depression initially was moving toward the west-southwest, it curved toward the west-northwest. Rains associated with this system had tropical depression began spreading across southwestern Mexico. As of late Sunday evening, TD-22E was located approximately to 105 miles to the south of Manzanillo, with essentially no change in strength. TD-22E was expected to continue traveling toward the west-northwest and strengthen on Monday to become Tropical Storm Tara.
• In North Indian Ocean:
  • Tropical Cyclone 5A, which was also identified as Cyclone Luban, was traveling toward the west-northwest across the Arabian Sea at the start of last week, approximately 600 miles to the east-southeast of the coast of Oman. Luban intensified as it curved toward the northwest. As of Sunday afternoon (local time), Cyclone Luban had made landfall to the north of Nishtun, Yemen. Additional information on Cyclone Luban can be found on the NASA Hurricane Blog Page
  • A tropical depression formed over the east central Bay of Bengal last Monday. By early Tuesday, this tropical depression had strengthened to become Tropical Cyclone 06B, or Cyclone Titli. Over the next two days, Cyclone Titli traveled to the northwest, headed toward the coast of India. By Thursday evening, Titli had made landfall along the eastern coast of India approximately 360 miles to the southwest of Calcutta, India. Titli weakened quickly as it traveled toward the northwest and then to the north and northeast. See the NASA Hurricane Blog Page for satellite images and additional information on Cyclone Titli.
• A dry 2018 water year draws to a close in California -- A meteorologist with NOAA's Climate Prediction Center wrote an "Event Tracker" article for the ClimateWatch Magazine noting many locations across California received precipitation totals that were well below average during the 2018 water year, which ended on 30 September 2018. An animated sequence of monthly maps was generated showing the percent of normal (1918-2010) monthly precipitation across California and surrounding states between October 2017 and September 2018 from data collected by the National Centers for Environmental Information. He noted that this past water year marked a return to the drier than average conditions across California after a relatively wet 2017 water year, which had helped replenish depleted reservoirs. As of the end of last month, the state's two largest reservoirs were below average in terms of capacity because of the dry conditions and the lack of an adequate snow pack from last winter. He wonders if the anticipated El Niño winter ahead will provide California with a wet water year. [NOAA Climate.gov News]
• El Niño/Southern Oscillation (ENSO) Diagnostic Discussion & El Niño watch -- NOAA's Climate Prediction Center (CPC) and the International Research Institute for Climate and Society (IRI) recently released their El Niño/Southern Oscillation (ENSO) Diagnostic Discussion showing that while ENSO-neutral conditions were observed to continue through September, the surface waters across the equatorial Pacific Ocean where beginning to warm, as indicated by an increase in the area of above-average sea surface temperatures. (ENSO-neutral conditions indicate neither El Niño or La Niña conditions.) Furthermore, subsurface waters were also warming in the waters of the equatorial Pacific to the east of the Dateline. In addition to oceanic conditions, the state of the tropical atmosphere through September also indicated ENSO conditions, but recent trends would suggest a developing El Niño. Based upon their assessment of the various computer forecast models that they use, the CPC and IRI forecasters have continued a El Niño watch that indicates a 70 to 75 percent chance that El Niño conditions will develop during the remainder of this Northern Hemisphere fall and continue through the boreal winter of 2018-19. Most of the models favor a weak to moderate episode.
  An ENSO blog written by a CPC contractor describes the metrics used by CPC and IRI forecasters to identify those oceanic and atmospheric conditions across the tropical Pacific basin in their decision-making process in determining the onset of an El Niño. They believe that the current ENSO-neutral conditions should become a El Niño event during the late fall and early winter 2018-19 (in the Northern Hemisphere), which has led to their continuing a El Niño watch. The blog also has accompanying graphics. [NOAA Climate.gov News]
  A detailed and more technical El Niño/Southern Oscillation Diagnostic Discussion with supporting maps and charts is available from CPC.
  Forecasters with the Australian Bureau of Meteorology recently issued an updated ENSO forecast from a Southern Hemisphere perspective. They reported that a warming of the tropical Pacific had been detected due to a weakening of the trade winds, which would suggest the onset of El Niño conditions. Furthermore, they felt that with the majority of forecast models indicated a transition to an El Niño. Therefore, they have raised their Bureau's ENSO Outlook to El Niño ALERT, which means that an approximately 70% chance exists for the occurrence of an El Niño in 2018, or roughly triple the normal likelihood. [Australian Government Bureau of Meteorology]
• Arctic Sea Ice Changes More Slowly with the loss of thick ice -- A scientist at NASA's Jet Propulsion Laboratory recently published an article showing the results based upon a 60-year record of changes in Arctic sea ice thickness from declassified U.S. Navy submarine measurements along with more recent data from four satellites. He found that the sea ice covering the Arctic Ocean has changed since 1958 from predominantly older, thicker ice to mostly younger, thinner ice. He concludes that with so little thick, old ice remaining, the rate of decrease in ice thickness has slowed. New ice grows faster but is more vulnerable to weather and wind, so ice thickness is now more variable, rather than dominated by the effect of warming associated with global climate change. [NASA Jet Propulsion Laboratory Feature]
• Records at tree ring lab used to decode Earth's climate history -- Ed Cook, one of the founding directors of the Columbia University's Lamont-Doherty Earth Observatory Tree-Ring Laboratory, recently was interviewed on his work decoding past climate patterns using tree rings during his 43 years at Lamont. His research involved developing "drought atlases," which are extensive, centuries-long records of wet and dry periods for a given region. These atlases include the North American Drought Atlas in 2004, the Monsoon Asia Drought Atlas in 2010 and the Old World Drought Atlas and Eastern Australia and New Zealand Drought Atlas, both published in 2015. [Lamont-Doherty Earth Observatory News]
• Key indicators of global climate change are updated by National Climate Assessment team -- A team of science experts associated with the United States Global Change Research Program (USGCRP) have recently updated a collection of 15 "climate indicators" to show how global climate has been changing. The scientists were using the latest data to produce graphics as part of the process needed to make updates prior to the scheduled release of the new Fourth National Climate Assessment in late 2018. This National Climate Assessment release is in fulfillment of a Congressional mandate to provide updated reports that will serve as an important resource for understanding and communicating climate change science and impacts in the United States. The fifteen indicators show trends that include increases in atmospheric greenhouse gas concentrations, increases in air temperatures, rising sea levels, and decreases in both ice extent and glacier mass. [NOAA Climate.gov News]
• Key indicators of global climate change are updated by National Climate Assessment team -- A team of science experts associated with the United States Global Change Research Program (USGCRP) have recently updated a collection of 15 "climate indicators" to show how global climate has been changing. The scientists were using the latest data to produce graphics as part of the process needed to make updates prior to the scheduled release of the new Fourth National Climate Assessment in late 2018. This National Climate Assessment release is in fulfillment of a Congressional mandate to provide updated reports that will serve as an important resource for understanding and communicating climate change science and impacts in the United States. The fifteen indicators show trends that include increases in atmospheric greenhouse gas concentrations, increases in air temperatures, rising sea levels, and decreases in both ice extent and glacier mass. [NOAA Climate.gov News]
• An international report is meant to be a "wake-up" on a 1.5 Celsius degree warming of Earth -- At the start of last week, the World Meteorological Organization (WMO) released a special report entitled "The Intergovernmental Panel on Climate Change (IPCC) Special Report on Global Warming of 1.5°C." This landmark report is intended to serve as a "wake-up" call about both the huge challenges and the benefits of limiting global warming to 1.5 Celsius degrees above pre-industrial levels in the context of strengthening the global response to the threat of climate change, sustainable development and efforts to eradicate poverty. [WMO Press Release]
• Nobel Prize for Economics involves Integrating innovation and climate with economic growth -- The Royal Swedish Academy of Sciences announced last week that it has awarded the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2018 to William D. Nordhaus of Yale University "for integrating climate change into long-run macroeconomic analysis" and Paul M. Romer of New York University's Stern School of Business "for integrating technological innovations into long-run macroeconomic analysis." [Nobel Prize Organization Press Release]
• An All-Hazards Monitor-- This Web portal provides the user information from NOAA's National Weather Service, FAA and FEMA on current environmental events that may pose as hazards such as tropical weather, fire weather, marine weather, severe weather, drought and floods. [NOAA/NWS Daily Briefing]
• Earthweek -- Diary of the Planet [earthweek.com]