WEEKLY WEATHER AND CLIMATE NEWS

13-17 August 2018

Items of Interest:

• Higher than normal ocean tides anticipated along nation's coasts early this week -- According to the NOAA National Ocean Service's High Tide Bulletin for Summer 2018, higher than average tides are expected between 9 and 14 July for most of the Pacific Coast of the US, stretching southward from Alaska to California and along the nation's Atlantic Coast, running from Maine southward to Florida's East Coast. Higher than average tides also can be expected surrounding Hawaii and the U.S. Pacific Islands. Only the Gulf Coast of the U.S. should not have higher than normal tides. A new moon that occurred early last Saturday morning (11 August), coupled with lunar perigee (when the Moon is closest to Earth) that was reached fifteen hours earlier on Friday afternoon, are responsible for the perigean spring tide that creates higher than normal high tides. [NOAA National Ocean Service News]
• Scientists employ various methods to study ancient climates -- Paleoclimatologists, or scientists who study ancient climate conditions, employ a variety of chemical, biological and other physical techniques to extract meaningful information on Earth's climate before instrumental and written historical climate records became available. They find clues in proxy indicators for climate that may be buried in sediments at the bottom of the oceans and lakes, frozen in layers of glaciers and ice caps, preserved in coral reefs and in the rings of trees. NOAA's National Centers for Environmental Information (formerly National Climatic Data Center, or NCDC) maintains a Paleoclimatology Branch that represents the world's largest achieve of data from the current instrumental and historical era and from the ancient paleoclimate times. [NOAA NCEI News]

Weather and Climate News Items:

• Eye on the tropics -- Tropical cyclone activity during the past week was found across the North Pacific and North Atlantic basins:
• In the western North Pacific basin:
  • Typhoon Shanshan traveled toward the north-northwest, passing slightly more than 300 miles to the east of Japan's Iwo To (also known as Iwo Jima) at the start of last week. Approaching the southeastern coast of Japan's Honshu Island, Shanshan strengthen to become a category 2 typhoon (on the Saffir-Simpson Scale). However, just before making landfall along the coast last Thursday, Shanshan curved to the east-northeast, sparing the Tokyo metropolitan area from the brunt of the strongest winds, although torrential rains spread across the region. Traveling to the east, Shanshan lost its tropical characteristics and became a midlatitude storm before dissipating. Satellite images and additional information on Typhoon Shanshan are available on the NASA Hurricane Page.
  • Tropical Depression 18W formed last Tuesday approximately 600 miles to the southeast of Okinawa. Moving slowly to the northwest toward Okinawa, this tropical depression intensified on Wednesday to become Tropical Storm Yagi, the 14th named storm of the 2018 Pacific typhoon season. By the start of this past weekend, Tropical Storm Yagi was spreading heavy rains across Okinawa as it curved toward the west-northwest and approached within 150 miles of the island. Yagi was located approximately 180 miles to the north-northeast of Taipei, Taiwan on Sunday. Forecasts have Yagi heading toward eastern China and make landfall to the south of Shanghai by Monday before dissipating onshore. The NASA Hurricane Page has satellite images and additional information on Yagi.
  • Tropical Depression 19W developed late last week to the east of Guam. Traveling toward the west and then northwest, this tropical depression intensified to become Tropical Storm Leepi. By late Sunday, Leepi was located approximately 150 miles to the south-southeast of Iwo To, Japan. Leepi was forecast to curve toward the west-northwest and approach the southern islands of Japan by midweek.
• In the eastern North Pacific basin:
  • Hurricane Hector was traveling generally toward the west as it crossed the 140th west meridian longitude, which marks the boundary between the eastern and central Pacific basins, at the start of last week. Hector crossed into the central Pacific basin as a category 4 hurricane on the Saffir-Simpson Scale since maximum sustained surface winds surrounding the central eye had reached 140 mph. Some strengthening of Hector occurred on Tuesday as maximum sustained winds were reported to be approaching 155 mph. This major hurricane, the first named tropical cyclone to reach the central North Pacific basin in 2018, continued toward the west and west-northwest through the remainder of last week. Hector passed within 200 miles of Hawaii's Big Island on Wednesday, producing large and dangerous surf with heights to 20 feet along the south-facing beaches of some of the main Hawaiian Islands. Hector began curving to take a track toward the west-northwest and northwest late in the week as it began weakening. By Saturday, the center of the category-3 Hurricane Hector had passed to within 210 miles to the north-northwest of Johnston Island. Hector continued to weaken as it tracked toward the west-northwest on Saturday. During the predawn hours of Sunday morning, Hurricane Hector was a category 1 hurricane that was located approximately 330 miles to the southeast of Midway Island. Current forecasts indicate that Hurricane Hector would weaken as it continues toward the west-northwest, passing across the International Dateline by early Monday (Hawaii Time). By moving across the Dateline (longitude 180 degrees), Hurricane Hector would be renamed Typhoon Hector as it has entered the western North Pacific basin (provided that this system maintains maximum sustained surface winds of more than 74 mph). The NASA Hurricane Page has satellite images and additional information on Hurricane Hector.
  • Tropical Storm Ileana was traveling toward the northwest offshore of the coast of southwestern Mexico at the start of last week. At that time, Tropical Storm Ileana was located approximately 120 miles to the south-southwest of Acapulco, Mexico. From Monday afternoon through early Tuesday morning, Ileana continued to parallel the southwestern Mexican coast, weakening as its circulation began to interact with the circulation of Hurricane John. By midmorning on Tuesday, Ileana had dissipated in the outer bands of Hurricane John approximately 175 miles to the south-southeast of the southern tip of Mexico's Baja California Peninsula. The NASA Hurricane Page has additional information and satellite images associated with Tropical Storm Ileana.
  • Tropical Storm John intensified rapidly at the start of last week as it was traveling toward the west-northwest approximately 340 miles to the southwest of Manzanillo, Mexico. By midafternoon on Monday, John became the fifth eastern Pacific hurricane of 2018. Hurricane John passed just to the east of Mexico's Socorro Island. As Hurricane John continued to travel toward the northwest, it strengthened to become a category 2 hurricane with maximum sustained winds of 105 mph. By Tuesday Hurricane John had absorbed Tropical Storm Ileana. On Wednesday, Hurricane John began weakening before being downgraded to a tropical storm early Thursday morning. By this past Friday morning, Tropical Storm John had weakened to a post tropical cyclone or remnant low approximately 475 miles to the south-southwest of San Diego, CA, with subsequent dissipation. Ocean swells generated by John were still affecting the coasts of the Baja California Peninsula and southern California. Additional information and satellite images on Hurricane John can be obtained from the NASA Hurricane Page
  • Tropical Depression 13-E (or TD-13E) formed late Monday evening approximately 1100 miles to the west-southwest of Cabo San Lucas at the southern tip of Mexico's Baja California Peninsula. Intensifying rapidly, TD-13E became Tropical Storm Kristy, the eleventh named tropical cyclone of 2018 in the basin during the predawn hours of Tuesday morning as it traveled westward. During the week, Kristy traveled generally westward before curving toward the north. By Thursday evening, the maximum sustained surface winds surrounding Kristy had strengthened to an estimated 70 mph, just shy of the 74-mph hurricane threshold. Reaching cooler waters, Kristy began weakening on Friday. Tropical Storm Kristy weakened to a post-tropical remnant low on Saturday morning approximately 1350 miles to the west of Cabo San Lucas, Mexico, before dissipating. The NASA Hurricane Page has satellite images and additional information on Tropical Storm Kristy.
• In the North Atlantic basin:
  • A subtropical storm identified as Debby formed over the waters of the North Atlantic approximately 1160 miles to the west of the Azores last Tuesday afternoon (local time). This system had both tropical and subtropical characteristics as it traveled initially in a direction to the north. By Wednesday morning, Subtropical Storm Debby strengthened and made a transition to become a tropical storm as it curved toward the north-northeast approximately 1175 miles to the west-northwest of the Azores. Over the next day Tropical Storm Debby continued to slowly curve toward the northeast as it moved farther north across the colder waters of the North Atlantic. By early Thursday evening, Debby became a post-tropical storm approximately 865 miles to the northwest of the Azores. For satellite images and more information on Tropical Storm Debby, consult NASA Hurricane Page.
• 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 ENSO-neutral conditions continued through July 2018, with near-average sea surface temperatures (SST) found across most of the eastern and central equatorial Pacific Ocean. In addition, the atmospheric system remained close to average, suggestive of the continuation of an ENSO-neutral situation with neither El Niño nor La Niña conditions prevailing. (An El Niño is a "warm phase" event where above average SST values are found in the eastern equatorial Pacific, while a La Niña is a "cold phase" event with below-average SSTs in the eastern Pacific) Most of the prediction models used by the forecasters indicate a continuation of ENSO-neutral conditions through August or the remainder of Northern Hemisphere's meteorological summer, before the possible development of El Niño during boreal autumn. Therefore, forecasters give an approximately 60-percent chance of the formation of El Niño conditions during meteorological autumn in the Northern Hemisphere (September through November), with an increase to a 70 percent chance during the boreal winter season of 2018-2019. Therefore, the CPC's ENSO Alert System Status remains at El Niño Watch. [NOAA Climate Prediction Center] Note: The criteria used for CPC's ENSO Alert System is available.
  An entertaining ENSO blog was written by a contractor with NOAA's Climate Prediction Center that explains why CPC and IRI forecasters are anticipating the transition from the current ENSO-neutral conditions to El Niño conditions during boreal autumn and winter, which constitute the remainder of 2018. She notes that sea surface temperatures across the equatorial Pacific during the last month were close to the long-term averages, indicating the ENSO-neutral conditions, but the ocean is warming underneath the surface. She also explains that the atmospheric circulation along the Equator, which is known as the Walker Circulation, could change in the next several weeks to cause a situation that would favor El Niño during the remainder of the year. [NOAA Climate.gov News]
  Forecasters with the Australian Bureau of Meteorology recently issued an updated ENSO forecast from a Southern Hemisphere perspective. They reported continuation of ENSO-neutral conditions through July. Since they foresee development of El Niño conditions during El Niño during austral spring and continuing into austral summer (or the remainder of the calendar year), the Bureau's ENSO Outlook status remains at "El Niño Watch". [Australian Government Bureau of Meteorology]
• Updated 2018 NOAA Atlantic hurricane outlook is released -- Forecasters at NOAA's Climate Prediction Center (CPC) issued their updated Atlantic Hurricane Season Outlook for 2018, in which they decreased the number of predicted named tropical cyclones for the North Atlantic Basin (including the Caribbean Sea and the Gulf of Mexico) from their initial seasonal outlook that they made in May. Specifically, they are now predicting a 60-percent chance of nine to thirteen named tropical cyclones (hurricanes and tropical storms with sustained surface winds of at least 39 mph), as compared with their earlier outlook of a 70-percent likelihood of 10 to 16 named systems. They also currently envision between four and seven hurricanes (with maximum sustained surface winds of 74 mph or higher) along with as many as two major hurricanes (Category 3 hurricanes or greater on the Saffir-Simpson Hurricane Intensity Scale with winds of at least 111 mph). This updated outlook represents decreases in their earlier forecasts of five to nine hurricanes and two to four major hurricanes. At the same time, the CPC forecasters indicated the likelihood of a near-normal season is now at 30 percent, while the chance of an above-normal season has dropped to 10 percent. For reference, long-term statistics show that an average Atlantic season consists of 12 named tropical cyclones and the six hurricanes that normally form during each year. Three of these hurricanes typically become major hurricanes. As of the early August, the Atlantic basin has experienced two tropical storms (Alberto and Debby) and two hurricanes (Beryl and Chris) so far during 2018.
  The CPC forecasters claim that the increased likelihood of below average tropical cyclone activity across the Atlantic basin is due to several factors that include more unfavorable conditions. Sea surface temperatures across the tropical Atlantic Ocean and Caribbean Sea are lower than average, along with a combination of stronger vertical wind shear (changes in the wind speed and/or direction with altitude), drier air and increased atmospheric stability in the region where tropical cyclones develop. In addition, CPC also updated its El Niño outlook (see previous entry) noting an increased likelihood of El Niño conditions during the next several months, which correspond to the peak of the Atlantic hurricane season; El Niño conditions tend to suppress tropical cyclone activity in the North Atlantic basin. [NOAA News]
  One week ago, Dr. Philip Klotzbach and associates at Colorado State University issued their updated Atlantic hurricane forecast was issued by in which they predicted a total of 12 named tropical cyclones for the entire 2018 season, including five hurricanes. The forecasters also anticipated one major hurricane and a below-average probability of at least one major hurricane landfall along the coasts of the continental United States and the islands in the Caribbean. [The Tropical Meteorology Project]
• Explaining how costs of weather and climate disasters are calculated -- Scientists at NOAA's National Centers for Environmental Information (NCEI) recently updated their explanation of how they calculate the costs incurred by the public from severe weather and climate events across the United States. These scientists are documenting and assessing the costs associated with hurricanes, drought, inland floods, severe local storms, wildfires, crop freeze events and winter storms. Input to their analysis is provided by a variety of public and private data sources. One of their products is the NCEI's list of U.S. billion-dollar disasters that dates back to 1980. As of early July, the list of events with losses exceeding $1 billion (CPI-Adjusted) each for the 1980-2018 span include 25 drought events, 29 flooding events, 9 freeze events, 99 severe storm events, 40 tropical cyclone events, 15 wildfire events, and 16 winter storm events. A mapping tool is available. [NOAA NCEI News]
• Weather scientist answers questions about extreme rainfall events -- Dr. David Novak, Director of NOAA's Weather Prediction Center and an extreme weather expert, was recently interviewed about extreme rainfall events. He was asked to provide a better understanding as to why extreme rainfall events occur and how timely forecasts of these events matter. [NOAA NCEI News]
• New forecast tool designed to improve flash flood warnings -- Scientists at NOAA's National Severe Storms Laboratory have developed a new forecasting tool called FLASH (Flooded Locations and Simulated Hydrographs Project) designed to help National Weather Service forecasters better predict the occurrence and timing of flash flooding events. FLASH combines real-time rainfall estimates from multiple weather radar units with real-time surface models involving the type of surfaces where rain is falling to create a highly detailed forecast for when specific rivers and streams will flood. [NOAA NCEI News]
• Study made of impact of solar activity during a hurricane emergency -- Scientists at NOAA's National Centers for Environmental Information (NCEI), the Cooperative Institute for Research in Environmental Sciences, NOAA’s Space Weather Center and the Massachusetts Institute of Technology have been studying the occurrence of solar activity and a category 5 hurricanane during the first week of September 2017, when overlapping and seemingly coincidental events brought about severe consequences especially on communications during an emergency. The timing of the solar activity was bad as it increased the vulnerability of several Caribbean communities. [NOAA NCEI News]
• Study made of impact of solar activity during a hurricane emergency -- Scientists at NOAA's National Centers for Environmental Information (NCEI), the Cooperative Institute for Research in Environmental Sciences, NOAA’s Space Weather Center and the Massachusetts Institute of Technology have been studying the occurrence of solar activity and a category 5 hurricanane during the first week of September 2017, when overlapping and seemingly coincidental events brought about severe consequences especially on communications during an emergency. The timing of the solar activity was bad as it increased the vulnerability of several Caribbean communities. [NOAA NCEI News]
• Data from DART® buoys help in tsunami preparedness -- Since 2001, NOAA's National Centers for Environmental Information has been building an archive of ocean change data collected by the fleet of 39 instrumented buoys called DART® (Deep-ocean Assessment and Reporting of Tsunamis) and from coastal tide gauge stations. These ocean change data can be used by researchers to improve coastal resiliency to tsunamis. The DART® buoys are equipped with bottom pressure recorders that monitor those wave changes, such as those associated with a tsunami, that may indicate a hazard. [NOAA NCEI News]
• Record high sea level reached in 2017 -- One of the key points in the State of the Climate in 2017 recently released by the American Meteorological Society was the global mean sea level in 2017 being the highest in the satellite record dating back to 1993. As of 2017, the global mean sea level was approximately three inches higher than in 1993. This increase has not been uniform around the globe, with some areas having experienced a reduction in local sea level. Several factors contribute to global sea level rise: added water from meltwater off glaciers and ice sheets, shifts in ground- and surface water storage and volume expansion due to ocean warming. [NOAA Climate.gov News]
• 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]