WEEKLY CLIMATE NEWS

25-29 September 2017

ITEMS OF INTEREST

September is National Preparedness Month -- The month of September has been declared National Preparedness Month (NPM), which aims to educate and empower Americans to prepare for and respond to all types of emergencies, including natural disasters. NPM is managed and sponsored by the Federal Emergency Management Administration's (FEMA) Ready Campaign in conjunction with the Ad Council, A toolkit of marketing materials is provided to help promote the month and represents the lead on this campaign that was originally launched in 2004. The overarching theme for 2017 NPM is "Disasters Don’t Plan Ahead. You Can.," with an emphasis on preparedness for youth, older adults, and people with disabilities and others with access and functional needs.
Week 4 of the 2017 NPM (24-30 September) the theme is "Get Involved! Be a Part of Something Larger." [FEMA's Ready.gov]
World Environmental Health Day to focus on air quality -- This Tuesday (26 September 2017) has been declared World Environmental Health Day by the International Federation of Environmental Health. This event is celebrated each year. The theme for the 2017 World Environmental Health Day is "Indoor & outdoor air quality." The World Health Organization (WHO) claims that poor quality air affects more than 80% of the world's population. [International Federation of Environmental Health]
End of the growing season -- If you live in the northern portion of the country, the growing season may have already ended as cold air masses have moved southeastward from Canada. Check the interactive maps produced by the Midwestern Regional Climate Center's Vegetation Impact Program (VIP) that show the date of the first occurrence of 28-degree and 32-degree Fahrenheit temperature readings during this fall across the 48 coterminous United States. (Use the "Current Season Freezes" in the "Shaded Maps Menu" on left to select the desired map.) Comparison can be made with corresponding maps showing the median dates of occurrence of the first 32-degree (or 28-degree) Fahrenheit temperatures (in the appropriate "Climatologies" sections) across the lower 48 states based upon a 30-year time series. (The median date means that half of the occurrences of a 32-degree reading over the 30-year normal occur prior to this date, while the other half occur after this date.) Additional other freeze-climatology maps are available including the earliest and latest dates of first autumnal freeze. Following first frost, some delightful days should occur during October and early November in what is often called "Indian Summer."
Free admission into the National Parks -- Next Saturday, 30 September 2017, has been designated by the National Park Service as fee-free day in honor of National Public Lands Day, which is celebrated annually at public lands across the nation on a Saturday in late September. This fee waiver will cover entrance and commercial tour fees in many of the national parks and monuments administered by the Park Service. [National Park Service Fee Free Days] The theme of the 24th annual National Public Lands Day 2017 is "Celebrate something we all share: Our Public Lands." [National Environmental Education Foundation]
Start of a new water year -- On Sunday, 1 October 2017, the new water year of 2018 will begin. As defined by the US Geological Survey and used by hydrologists in reports dealing with surface water supply, the "water year" is defined as the 12 months commencing on 1 October of any given year and ends on 30 September of the following year. The water year is designated by the calendar year in which it ends, such that the 2018 water year runs through 30 September 2018.
High-quality maps of October 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 October 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.
October 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 October, 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.
Monitoring the drought -- During this past summer, western sections of the nation continued to experience major drought. See how the drought is monitored and assessed by reading this week's Supplemental Information…In Greater Depth.

CURRENT CLIMATE STATUS

Review of August 2017 (and seasonal) weather and climate for the globe -- Preliminary data analyzed by scientists at NOAA's National Centers for Environmental Information (NCEI) indicated:

The global combined land and ocean average surface temperature for August 2017 was 1.49 Fahrenheit degrees above the 20th-century average (1901-2000) for the month, which makes last month the third warmest August since a sufficiently dense network of global temperature records began in 1880. When considered separately, the land surface temperature for this recently concluded month was the second highest August temperature in the 138-year record, with a monthly temperature that was approximately 2.11 Fahrenheit degrees above the 20th-century average. The monthly temperature departure of the ocean surface was 1.28 Fahrenheit degrees above the 20th-century average, which was the fourth highest August temperature on record. ENSO neutral conditions prevailed during August 2017, with near to slightly below-average sea surface temperatures found across the central and eastern equatorial Pacific Ocean.

NOTE:

NOAA Climate.gov News

A global map of Selected Significant Climate Anomalies and Events for August 2016 is available from NCEI.
During the last three months, which constitutes meteorological summer in the Northern Hemisphere and meteorological winter in the Southern Hemisphere, the combined global land and ocean average temperature for 2017 was 1.46 Fahrenheit degrees above the 20th-century average, which also was the third highest for this three-month period since 1880. The June-August 2016 temperature for the global land surface was the second highest for any boreal summer in the last 138 years, while the ocean temperature was the fourth highest.
According to data provided by the National Snow and Ice Data Center (NSIDC), the average August Arctic sea ice extent in the Northern Hemisphere was approximately 24 percent below the 1981–2010 average, making it the third smallest August Arctic sea ice extent since satellite records began in 1979. In the Southern Hemisphere, the August 2017 Antarctic sea ice extent was the second smallest August extent in the 39-year period of record.
[NOAA/NCDC State of the Climate]

Monitoring torrential rainfall across Puerto Rico from space -- As Hurricane Maria traveled across Puerto Rico last week, NASA scientists were analyzing data collected by instruments onboard NASA's GPM (Global Precipitation Mission) satellite. Between Monday (18 September) evening and Wednesday (20 September) evening, as much as 20 inches of rain were recorded by the satellite, which were similar to amounts recorded by surface rain gauges. [NASA Earth Observatory]

CLIMATE MONITORING

Sea ice on Arctic Ocean reaches its smallest seasonal extent -- During the last week scientists at NASA's Goddard Space Flight Center and National Snow and Ice Data Center announced that the sea ice cover on the Arctic Ocean appeared to have shrunk to its smallest annual extent on 13 September 2017. Based on preliminary analysis of data collected by satellite sensors, the Arctic sea ice coverage on that date was determined to be only 1.79 million square miles, which would represent an area that would be the eighth smallest seasonal extent since satellite-based observations began in 1978. The lowest measured Arctic sea ice extent remains on 17 September 2012, when 1.31 million square miles of ice covered the Arctic Ocean. [NASA Earth Science News Team], [NOAA Climate.gov News] or [National Snow & Ice Data Center News]
Satellites see gains in groundwater across India -- An international team of scientists from the US, India and Austria have used ground observations along with data collected by NASA's GRACE (Gravity Recovery and Climate Experiment) satellites to create a map of the changes in groundwater across India between 2003 and 2014. They found an increase in the water stored in the aquifers in some parts of India was increasing of this time interval, especially in the western and southern sections of the country. [NASA Earth Observatory]

CLIMATE FORCING

Investigating the effects that El Niño and La Niña events play on winter jet stream and US climate -- A contractor with NOAA's Climate Program Office wrote a feature for ClimateWatch Magazine in which she describes with a pair of maps how the onset of an El Niño or La Niña event in the equatorial Pacific can impact the United States as a consequence of a marked shift in the path of the mid-latitude jet streams. These events that generate anomalous atmospheric and oceanic circulation regimes often have a greater impact upon the winter position of the upper tropospheric jet and hence, the weather and climate of the US during winter. [NOAA Climate.gov News]

CLIMATE FORECASTS

New Seasonal Climate Outlooks for the remainder of 2017 issued -- Forecasters at the NOAA Climate Prediction Center (CPC) recently released their new national Three-Month (Seasonal) Climate Outlooks for October through December 2017, corresponding to the last two months of the meteorological autumn season (in the Northern Hemisphere) and the first month of meteorological winter. Specific details of their outlooks include:
- Temperature and precipitation outlooks -- According to their temperature outlook, nearly all of the contiguous United States should experience a high chance of above average temperatures for the three upcoming months. The greatest probability of such an occurrence should be found across the Southwest, centered upon Arizona and New Mexico. The Northeast, extending from the Great Lakes and the Middle Atlantic States to New England, was also expected to have a good chance of above average temperatures. The outlook indicates that the northern Plains (Montana and North Dakota) would have nearly equal chances of warmer or cooler than normal conditions.
  The CPC precipitation outlook calls for a better than even chance for below average precipitation during the next three months across southeastern quadrant of the nation, with the greatest probability of drier than average conditions being centered on the Gulf Coast consisting of eastern Texas, Louisiana and southwestern Mississippi. On the other hand, the northwestern quadrant of the country, especially centered on Idaho, Montana and Wyoming, would have the best chances of above average precipitation through the end of the year. The remainder of the contiguous states were given essentially equal chances of below and above average precipitation for October through December 2017.
  A summary of the prognostic discussion of the 3-month outlook for non-technical users is available from CPC. These forecasts were based in part that assuming that ENSO-neutral conditions would persist through the meteorological autumn (with neither an El Niño or La Niña event anticipated), followed by a possible transistion to La Niña conditions by the start winter (December-February).
  A description is also provided as how to read these 3-class, 3-month Outlook maps.
- Seasonal Drought Outlook released -- The forecasters at NOAA's Climate Prediction Center also released their US Seasonal Drought Outlook last week that would run from late-September through December 2017. Their outlook would call for persistence of extensive drought conditions across the northern Plains, extending from the Continental Divide in Montana eastward to the Dakotas, scattered areas of the Midwest and in the southern sections of California and Arizona. Drought conditions were also expected to develop across sections of the lower Mississippi Valley and the central Gulf Coast. On the other hand, a few sections of the Northwest and the Plains could see some improvement in drought conditions during the rest of the year, including some areas that could be removed from drought listings. The remainder of the nation does not appear to be headed for drought conditions. Note: a Seasonal Drought Outlook Discussion is included describing the forecasters' confidence.

CLIMATE AND SOCIETY

Taking another look at Hurricane Harvey's record rains and catastrophic flooding -- A meteorologist with NOAA's Climate Prediction Center made an analysis of the impacts that Hurricane Harvey had on the upper Texas Gulf Coast, especially the Houston metropolitan area. In addition to describing the record rainfall that resulted in catastrophic flooding, he considered the probability of occurrence of such an extreme event. He also discussed some of the societal impacts. [NOAA Climate.gov News]
Earthweek -- Diary of the Planet [earthweek.com]

Concept of the Week: Keeping your cool!

In order to survive, humans need to maintain a nearly constant internal core temperature that is within several degrees of 98.6 degrees Fahrenheit. Your internal temperature depends upon an energy balance involving the gain and loss of energy from radiation (incoming solar versus incoming and outgoing infrared radiation), sensible heat transfer (conduction and convection), latent heat of evaporation (respiration and perspiration) and the body's metabolic rate. This heat transfer depends upon the differences between skin temperature and the ambient air temperature of the surroundings. In addition, wind and atmospheric humidity can affect the rate of sensible and latent heat transfer. Problems arise when either too much or too little heat flows to or from the body, yielding hypothermia and hyperthermia (heat stress) conditions, respectively.

When the air temperature increases, heat flow from the body is often reduced. Heat flow can be increased to maintain stable temperatures involuntarily by thermoregulatory processes such as increased perspiration (sweating) and dilation of the blood vessels. Humans can also act to prevent hyperthermia by selecting lightweight and light colored clothes, as well as seeking of shade and well ventilated locations. Unfortunately, high atmospheric humidity that often accompanies high summer temperatures also reduces body heat loss since evaporative cooling by perspiration is suppressed. During the summer, the National Weather Service alerts the public of potentially dangerous combinations of high air temperature and atmospheric humidity levels by calculating the Heat Index.

Statistics kept by the National Weather Service reveals that heat (along with high humidity) is responsible for the greatest number of weather-related deaths across the nation during the 10-year period (2001-2010), with 115 fatalities occurring per year. By comparison, 116 fatalities per annum are caused by tropical cyclones (hurricanes and tropical storms), 56 deaths per year are associated from tornadoes and 25 deaths annually caused by the cold (low temperatures). (Note: The large number of fatalities associated with the hurricanes of 2005, which totaled 1016 deaths in the US due primarily to Hurricane Katrina, has inflated the annual averages associated with tropical cyclones.) Furthermore, concern has been raised that during this century, more frequent and more severe heat waves due to global climate change could become more common, leading to a greater risk of hyperthermia and, ultimately, to higher morbidity rates.

Historical Events:

25 September 1939...A West Coast hurricane moved onshore south of Los Angeles bringing unprecedented rains along the southern coast of California. Nearly five and a half inches of rain drenched Los Angeles during a 24-hr period. The hurricane caused $2 million in damage, mostly to structures along the coast and to crops, and claimed 45 lives at sea. "El Cordonazo" produced 5.66 in. of rain at Los Angeles and 11.6 in. of rain at Mount Wilson, both records for the month of September. (David Ludlum) (The Weather Channel)
26 September 1963...San Diego, CA reached an all-time record high of 111 degrees. Los Angeles hit 109 degrees. (David Ludlum)
27 September 1816...A black frost over most of New England kills unripened corn in the north resulting in a year of famine. (David Ludlum)
27-28 September 1953...The strongest wind gust ever recorded during a hurricane was 175 mph at Chetumal, Mexico. (The Weather Doctor)
28 September 1893...Albuquerque, NM was soaked with 2.25 inches of rain, enough to establish a 24-hour record for that city. (The Weather Channel)
28 September 1986...Torrential rains and floods were responsible for South Africa's worst natural disaster in Natal. As much as 35 in. of rain fell between the 25^th and 29^th to the northeast of Empangen, resulting in 317 deaths and 163 people missing. Topsoil from some farms was completely washed away leaving only bedrock. (Accord Weather Calendar)
30 September 1992...Fairbanks, AK averaged a frigid 31.7 degrees for the month, 13.2 Fahrenheit degrees below normal and a record. Beginning on the 9^th, a record low was set for every day of the month. The temperature plunged to 3 degrees on the 30^th, the lowest ever for September. Snowfall for the month totaled 24.4 inches, more than three times the previous record. The snows never melted. Plant foliage still green, was frozen into place and week long power outages occurred as whole trees bent over onto power lines in the heavy wet snow. (Intellicast)
1 October 2006...Wichita, KS recorded its hottest October day ever on the 1st with a 97-degree high temperature. (The Weather Doctor)

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