WEEKLY CLIMATE NEWS

16-20 October 2017

ITEMS OF INTEREST

Worldwide GLOBE at Night 2017 Campaign is underway -- The tenth in the series of GLOBE at Night citizen-science campaigns for 2017 will continue through Friday, 20 October. 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 (Cygnus in the Northern Hemisphere and Grus in the Southern Hemisphere) with the seven magnitude/star charts of progressively fainter stars. Activity guides are also available. The GLOBE at night program is intended to raise public awareness of the impact of light pollution. The next series in the 2017 campaign is scheduled for 10-19 November 2017. [GLOBE at Night]
Monitoring El Niño and La Niña -- Scientists have suggested that a La Niña event could develop during late meteorological autumn in the Northern Hemisphere and continue into the winter season. This event could affect weather patterns across the United States during the upcoming winter months. For more details on how to monitor these phenomena, please read this week's Supplemental Information...In Greater Depth.

CURRENT CLIMATE STATUS

National weather and climate reviewed for September 2017 -- Scientists at the NOAA National Centers for Environmental Information (NCEI) recently reported on their analysis of preliminary weather data collected during the month of September 2017. Based upon these data, this recently concluded September was the third warmest September across the contiguous United States since sufficiently reliable climate records began in 1895. The nationwide monthly average for September was 66.3 degrees Fahrenheit, which was 2.7 Fahrenheit degrees higher than the 20th century (1901-2000) average. More than half of the states reported above to much above statewide average temperatures for the month. Nine states in the northeastern quadrant of the nation, running from the Great Lakes to New England and the Middle Atlantic, had statewide temperatures that ranked within the top ten highest in the 123-year period of record.
Alaska reported a statewide temperature of 42.8 degrees Fahrenheit, the 15th highest temperature reading for the state's period of record that commenced in 1925.
The September 2017 average precipitation across the "Lower 48 states" was approximately 0.27 inches below the 20th century average with a nationwide average of 2.70 inches making it the 37th driest September since 1895.
Louisiana experienced its driest September on record, only one month removed from having its second wettest August, courtesy of Hurricane Harvey. Four other states in the Mississippi Valley and Great Lakes (Arkansas, Illinois, Michigan and Missouri) had statewide September precipitation totals that ranked within the ten smallest in 123 years for their respective states. Much below average September precipitation was also reported across a wide area of the Midwest and Middle Atlantic states. On the other hand, above to much above average statewide precipitation was reported across the Southeast and the states in the northern Plains and across the Rockies and the Great Basin.
The area-averaged precipitation for the 48 continuous states for the first nine-months of 2017 was 3.16 inches above the 20th century average, and was the most since 1895, exceeding the previous record that was set in 1979.
[NOAA/NCEI State of the Climate]
NOTE: A description is provided of the climatological rankings employed by NCEI for their monthly and seasonal maps. [NOAA/NCEI]
Assessing how climate conditions affected this fall deadly wildfires in California -- A contractor to NOAA's Climate Program Office wrote a feature for the ClimateWatch Magazine identifying the various climate conditions that helped lead to this month's deadly wildfires across northern California. These conditions included near-record precipitation across this region of the Golden State last winter (December 2016-February 2017), which led to a lush and productive growing season. A dry and record hot summer (June – August 2017) followed, which created a high risk for wildfires in autumn. She also provided a map showing the projected increase in the number of "very large fire weeks" mid-century (2041-2070) compared to the 1971-2000 conditions. [NOAA Climate.gov News]
Natural-color images made from data collected by the MODIS instruments on NASA's Aqua and Terra satellites at the start of last week show the smoke plumes from the wildfires in the "wine country" of northern California. These plumes were being carried out over the nearby North Pacific Ocean by winds from the east and northeast. [NASA Earth Observatory]
False-color images were made at midweek from the Operational Land Imager (OLI) on NASA's Landsat 8 satellite that showed fire locations near Santa Rosa and other communities in northern California's wine country. [NASA Earth Observatory]
As of late last week, low atmospheric humidity, gusty northerly winds and above average temperatures were exacerbating the critical fire situation. Forecasters from NOAA's Storm Prediction Center were issuing Fire Weather Forecasts that remained "Elevated" across sections of California, while local National Weather Service Forecast Offices in California were continuing to post Red Flag Warnings, which indicated that local conditions remained conducive for extreme wildfire behavior. [NOAA News]
A very wet 2017 water year draws to a close in California -- A meteorologist with NOAA's Climate Prediction Center wrote an article for the ClimateWatch Magazine noting the large amounts of precipitation that fell across the Sierra Mountains in central and northern California during the 2017 water year, which ended on 30 September 2017. He noted that some locations received record or near record precipitation, which helped eliminate the earlier drought and help stock the reservoirs with water for this past summer. However, he noted that California's wet water year occurred during a La Niña, rather than an El Niño winter, which is often expected. [NOAA Climate.gov News]

CURRENT CLIMATE MONITORING

Maps show historical extremes of autumn temperature and precipitation across the nation -- NOAA's National Centers for Environmental Information has assembled a collection of eight maps of the 48 contiguous United States that display the years of occurrence of local and regional "coldest, warmest, driest and wettest autumns on record" as determined from the seasonal maximum, minimum and average temperatures and the seasonal precipitation (Sep-Nov). [NOAA/NCEI National Climate Report]
Cause of recent global carbon dioxide spike is pinpointed -- Analysis of the first 28 months of data collected from instruments onboard NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite have led a team of scientists to attribute the recent large annual increases in atmospheric carbon dioxide to Earth's tropical regions, in particular, the occurrence of the large 2015-16 El Niño. This El Niño resulted in northern South America being the driest in the last 30 years, leading to decreased photosynthesis; above normal temperatures in equatorial Africa leading to increased decomposition; and the second driest season in Oceania leading to increased wildfires. The scientists were from NASA, the National Center for Atmospheric Research, Caltech, Arizona State University. [NASA Jet Propulsion Laboratory News]

CLIMATE FORECASTS

El Niño/Southern Oscillation (ENSO) Diagnostic Discussion & La Niña 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 that showed ENSO-neutral conditions were observed to continue through September, indicating neither El Niño or La Niña conditions, as cooler than average surface waters expanded across the eastern and central equatorial Pacific Ocean. In addition, subsurface waters were also cooling. In addition to oceanic conditions, the tropical atmosphere also indicates ENSO conditions. Based upon their assessment of the various computer forecast models that they use, the CPC forecasters have continued a La Niña watch that indicates a 55 to 65 percent chance that a La Niña event will develop during this Northern Hemisphere fall and continue through the boreal winter of 2017-18.
An ENSO blog written by a CPC contractor describes how CPC and IRI forecasters have been monitoring the atmospheric circulation and the sea surface temperature patterns across the tropical Pacific basin. They believe that the current ENSO-neutral conditions could become a La Niña event during the late fall and early winter 2016-17 (in the Northern Hemisphere), which has led to their continuing a La Niña watch. The blog also has accompanying graphics. [NOAA Climate.gov News]
A detailed 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 continuation of ENSO-neutral conditions. They noted that weakened trade winds had interrupted the cooling trend of surface waters. Furthermore, they felt that with the majority of forecast models indicating additional cooling during the last several months of 2017, a transition to La Niña conditions was possible in December, which corresponds to Southern Hemisphere summer. [Australian Government Bureau of Meteorology]
NOAA's lead hurricane season forecaster interviewed on current Atlantic hurricane season -- Dr. Gerry Bell, NOAA's lead hurricane season forecaster, was recently interviewed and asked to provide his view of the current Atlantic hurricane season, which has been very active with ten hurricanes, including five major hurricanes (category 3 or greater on the Saffir-Simpson Scale) and how this activity compares with the outlook that he and his colleagues provided in May and August. [NOAA Stories]
Warming ocean waters could lead to a 70-percent increase of financial loss due to hurricanes -- In a recent study published by researchers at the University of Vermont, financial losses caused by hurricanes could increase more than 70 percent by 2100 if the oceans warmed at a rate projected by the Intergovernmental Panel on Climate Change (IPCC). The study focused upon coastal counties in South Carolina located within 50 miles of the coastline, including the Charleston metropolitan area, that were subjected to model simulations hurricanes involving two scenarios. One scenario involved no changes in ocean temperature between 2005 and 2100, while the other had the ocean temperature change at a rate predicted by the IPCC's worst-case scenario. [University of Vermont News]

CLIMATE AND SOCIETY

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

Concept of the Week: Seawater Salinity and Carbon Dioxide

The contemporary concern regarding global climate change has caused scientists to study the various factors that govern the ocean's ability to absorb atmospheric carbon dioxide. Concentrations of atmospheric carbon dioxide, a greenhouse gas, are on the rise primarily because of increased burning of fossil fuels. Higher levels of atmospheric carbon dioxide may be contributing to increased global temperatures, a condition often identified as global warming. The ocean's role in regulating the concentration of atmospheric carbon dioxide depends on the temperature, salinity, and biological components of surface waters.

Studies show that the ocean's ability to absorb carbon dioxide is primarily temperature dependent. As noted in Chapter 8 of your textbook, gases are more soluble in cold seawater than warm seawater. Hence, changes in sea surface temperature affect the ability of the ocean to absorb carbon dioxide. We also found in Chapter 1, photosynthetic organisms assimilate carbon dioxide and release oxygen. Through cellular respiration, all organisms release carbon dioxide. Therefore, biological activity affects the ocean's ability to absorption of atmospheric carbon dioxide.

What about the effects of changes in salinity on the ocean's uptake of atmospheric carbon dioxide? Research from the Pacific Ocean near Hawaii provides some insight on this question. For nearly 20 years, scientists have been collecting physical, chemical and biological data through a large column of ocean water at Station ALOHA, a sampling site about 100 km (62 mi) north of Oahu that appears representative of oceanic conditions in the central North Pacific. In 2003, David M. Karl, a biogeochemist at the University of Hawaii in Honolulu, reported a decline in the rate at which surface ocean waters were absorbing carbon dioxide from the atmosphere. In 2001, the rate of carbon dioxide uptake was only about 15% of the rate in 1989. Why the change in carbon dioxide uptake? In this region of the Pacific north of Hawaii, sea surface temperatures showed no significant change during the period of observation but precipitation decreased and evaporation increased. Less precipitation associated with drought coupled with higher rates of evaporation caused the surface water salinity at ALOHA to increase by about 1%. Increasing salinity inhibits water's ability to absorb gases including carbon dioxide. Karl and his colleagues attribute 40% of the decline in the ocean's carbon dioxide uptake to the saltier waters. The balance of the decline may be due to changes in biological productivity or ocean mixing.

Projected changes in global climate indicate significant changes in precipitation around the globe including reduced precipitation over various large areas of the oceans, resulting in potential "drought" conditions. Since changes in oceanic salinity result from changes in precipitation, the contribution that salinity plays on future assimilation of atmospheric carbon dioxide by the ocean also becomes an important consideration.

Historical Events:

16 October 1913...The temperature in Downtown San Francisco soared to 101 degrees to equal their record for October. (The Weather Channel)
16 October 1988...The afternoon high temperature of 100 degrees at Red Bluff, CA was the latest such reading of record for so late in the autumn season. (The National Weather Summary) (Storm Data)
17-18 October 2005...Heavy rain fell on Las Vegas, NV over the two-day period, with a rainfall total of 1.42 inches, which broke the full month record for October set in 1992. (The Weather Doctor)
17-19 October 2007...According to NOAA's Storm Prediction Center, 87 tornadoes were reported in the United States on these three days -- a new record outbreak for the month. With the outbreak, the monthly total of confirmed tornado reached 105, the second highest for October, behind the 117 in October 2001 since records began in 1950. Over 300 reports of severe weather were filed on 18 October across the lower and mid-Mississippi Valleys. (The Weather Doctor)
18 October 1984...Heavy snow began falling late on the 17^th at Salt Lake City and when it ended, 18.4 inches fell, setting a new 24-hour snowfall record. (Intellicast)
18-19 October 2005...Hurricane Wilma developed a tiny, well-defined eye and began intensifying rapidly, reaching Category 5 strength with a record-setting pressure of 882 millibars (26.04 inches of mercury) by 19 October. The rapid intensification from tropical storm to Category 5 hurricane in 24 hours was the fastest ever recorded in the Atlantic Ocean, and the second-fastest worldwide, after Super Typhoon Forrest. (National Weather Service files)
20 October 2004...Rain at two stations in Nevada broke the state's previous 24-hour maximum precipitation record of 7.13 inches set previously at Mt. Rose Highway Station (31 January 1963). The new state record of 9.78 inches was established at Mt. Charleston, while Kyle Canyon also broke the old record with 8.75 inches. (Accord Weather Guide Calendar)
21 October 1996...Portland, ME received 13.32 inches of rain to set a 24-hour maximum precipitation record for the Pine Tree State. (NCDC)
22 October 1987...Yakutat, AK surpassed their previous all-time yearly precipitation total of 190 inches. Monthly records were set in June with 17 inches, in September with 70 inches, and in October with more than 40 inches. (Sandra and TI Richard Sanders - 1987)
22 October 2005...Isla Mujeres, Mexico set the Northern Hemisphere's and Western Hemisphere's 24-hour rainfall record with 64.33 inches thanks to Hurricane Wilma. (National Weather Service files)

Return to RealTime Climate Portal