WEEKLY CLIMATE NEWS

10-14 September 2018

ITEMS OF INTEREST

September is National Preparedness Month -- The upcoming month of September has been declared National Preparedness Month (NPM), which is 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 2018 NPM is "Disasters Happen. Prepare Now. Learn How" with an emphasis on planning. Week 2 of the 2018 NPM ends this Saturday (15 September) with the theme of "Learn Life Saving Skills." Saturday has also been designated as a National Day of Action.
Week 3 of the 2018 NPM (16-22 September) has the theme "Check Your Insurance Coverage." [FEMA's Ready.gov]
Celebrating preservation of Earth's ozone layer -- This Sunday, 16 September, has been designated by the United Nations as World Ozone Day, the International Day for the Preservation of the Ozone Layer. This day is celebrated to mark the day back in 1987 when the Montreal Protocol was signed. [United Nations Environment]
Approaching the peak in the Atlantic hurricane season -- The historic or statistical annual peak in the Atlantic hurricane season will occur near the end of this week (8-12 September), as determined as the date during the entire season with most frequent number of named tropical cyclones (tropical storms and hurricanes), based upon over 100 years of record. This date corresponds closely with the time of peak sea-surface temperatures across those sections of the North Atlantic considered hurricane-breeding areas. [NWS National Hurricane Center]
One for the record books -- If you would like more background information concerning how various temperature and precipitation extremes are identified as record events from a station's climate record, please read this week's Supplemental Information...In Greater Depth.

CURRENT CLIMATE STATUS

Above-average sea surface temperatures were found across western North Atlantic in August 2018 -- NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) recently assembled an image of the sea surface temperature departures from long-term averages for the month of August 2018 over the North Atlantic Ocean basin. This visual was produced by the NOAA Environmental Visualization Laboratory from data collected by NOAA’s fleet of polar orbiting satellites. The map also shows much above-average temperatures across waters off the coast of New England and eastern Canada, where some locations experienced temperatures 9 Fahrenheit degrees above average. [NOAA NESDIS News]

CLIMATE MONITORING

Making the discovery of NOAA data easier -- A search engine entitled "Dataset Search" that is dedicated to searching environmental datasets held by the National Centers for Environmental Information (NCEI) has been unveiled for public use. This search engine was developed in a partnership between NCEI and Google, a U.S. technology company specializing in Internet-related services and products. NCEI hosts over 37 petabytes of data, which include NOAA datasets, such as weather, geophysical, and ocean records. [NOAA NCEI News]
Satellite monitors summertime "ship tracks" in North Pacific -- A natural-color image was made in late August by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on NASA's Aqua satellite showing "ship tracks" across the North Pacific Ocean approximately 900 miles off the northern California and southern Oregon coast. "Ship tracks" are distinctive, linear clouds created when water vapor condenses upon tiny hygroscopic particles (aerosols) that are emitted in the exhaust from ships traveling across the region. Ship tracks typically form in areas where thin, low-lying stratus and cumulus clouds are present such as off the west coasts of North and South America. In a study conducted by German researchers, ship track clouds in the North Pacific appear most often in meteorological summer in the Northern Hemisphere (May, June, and July) and are only occasionally present in meteorological winter (December, January, and February). [NASA Earth Observatory]

CLIMATE FORCING

Deployment of large-scale wind and solar farms in the Sahara could increase area's rainfall and vegetation -- A team of researchers from the U.S., China and Italy recently reported on the results of their climate and vegetation model experiments focusing upon the deployment of large-scale wind and solar farms across the Sahara region of Africa. They found that in addition to supplying sufficient energy to replace the energy generated by fossil fuels, the wind and solar farms could result in more than doubling the amount of rainfall in the arid Sahara, along with substantial increases in the rainfall in the semi-arid Sahel located to the south. The increase in rainfall could promote more widespread vegetation. The reason for this increase in rainfall appears to be due to changes to land surface properties involving the reduction in the surface reflectivity (or albedo) and the increase in land surface friction and low-level convergence of air, thus producing upward motion and precipitation. [University of Maryland News]

CLIMATE IMPACTS ON THE BIOSPHERE

Changes seen in the humpback whale population off the Hawaiian Islands -- Marine biologists and other researchers, including those at NOAA's Hawaiian Islands Humpback Whale National Marine Sanctuary, have been attempting to reconcile the reasons for the reduced number of sightings of humpback whales in the waters off the Hawaiian Islands over the last three seasons when these whales return from Alaskan waters for the winter. Several reasons include those involving food that are associated with Pacific Ocean temperatures, including El Niño events, the Pacific Decadal Oscillation and "The Blob", an extreme marine heatwave with anomalously elevated temperatures off the coast of the Pacific Northwest and Alaska in 2013. [NOAA National Marine Sanctuaries News]

CLIMATE MODELING

Impacts from El Niño and La Niña events expected to intensify with a warming climate -- Researchers from the National Center for Atmospheric Research (NCAR) and the University of California, Santa Barbara recently reported that during the occurrence of a warm phase El Niño event (anomalous atmospheric and oceanic circulation patterns featuring warmer than average waters in the eastern equatorial Pacific Ocean) or its opposite, the cold phase La Niña event (with below average equatorial waters in the eastern Pacific), more intense impacts in the weather and climate are found over many land regions as a consequence of a warming climate. These changes would be found in amplified changes in the temperature, precipitation and wildfire risks. The researchers came to these conclusions based upon running numerous computer simulations using the NCAR-based Community Earth System Model and NOAA's Geophysical Fluid Dynamics Laboratory Earth System Model. The large number of model simulations allowed the scientists to distinguish impacts linked to El Niño and La Niña conditions from those caused by the natural chaos in the climate system. [NCAR & UCAR News]

CLIMATE AND HUMAN HEALTH

Efforts made to determine what wildfires are emitting to help improve air quality and smoke forecasts -- A feature was posted to NOAA's ClimateWatch Magazine that describes how atmospheric scientists at NOAA's Earth System Research Laboratory and colleagues have been participating in FIREX (Fire Influence on Regional and Global Environments Experiment), a multi-agency project designed to understand what chemicals are produced directly or indirectly by wildfires. New equipment was used in FIREX revealed certain toxic chemicals that could adversely affect human health and the economy. In addition, work is being done to improve current smoke forecast models, such as the U.S. Forest Service's BlueSky tool and the NOAA Hazard Mapping System Fire and Smoke Product that predict where smoke plumes will travel. [NOAA Climate.gov News]

CLIMATE AND SOCIETY

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

Concept of the Week: End of the Growing Season

As we move into autumn, we often contemplate the end of the growing season as daylight shortens and temperatures begin to fall across many areas of the nation. The length of the growing season depends upon the plant species, as well as the climate of the locale, meaning that several ways can be used to define the growing season.

Many crops, especially vegetables and fruits, are sensitive to relatively low air temperatures. In spring, when many crops are emerging and in various stages of development they are more vulnerable to air temperatures near 32 degrees Fahrenheit. But by fall, many of these plants have become hardy. Generally speaking, a killing frost would occur when the temperature around the plant would fall to a point that would kill all but the hardiest vegetation. Sometimes, other terminology is used. When air temperatures fall between 29 and 32 degrees Fahrenheit, a so-called "light freeze" occurs. While tender plants such as tomatoes, peppers, corn and cucumbers would be killed when temperatures fall to around 29 degrees, these conditions would have little destructive effect on other hardier vegetation. A "moderate freeze" typically occurs between 25 and 28 degrees, which would have a widely destructive effect upon most vegetation. For temperatures of 24 degrees or lower, a condition called a "severe freeze", heavy damage would occur with most plants that are not dormant. Apples are damaged when the temperature drops below 20 degrees. Under these conditions, the soil would have frozen solid to a depth dependent upon the duration of the freeze, as well as the soil type and soil moisture.

In most mid latitude climates, the growing season is often used synonymously with the frost-free season, loosely defined as the length of time between the last killing frost in spring and the first killing frost in the autumn. The National Centers for Environmental Information has produced climatological tables that identify those median dates (a 50 percent occurrence) during spring and fall when the temperature at a station falls to 36, 32, 28, 24 or 20 degrees Fahrenheit for the last time in spring or the first time in autumn. While the exact time span that a plant survives would vary by plant type, the growing season for climatological purposes is often related to the interval when the daily minimum temperature remains above 32 degrees. The Midwestern Regional Climate Center (MRCC) is maintaining the MRCC Frost/Freeze Guidance Project as part of the Vegetation Impact Program (VIP) with website displaying a variety of freeze maps across the 48 contiguous United States. These maps show the 28-degree and 32-degree Freeze Climatologies as well as the current freeze statistics. Check the map showing the median date of occurrence of the first 32-degree Fahrenheit temperature in fall across the 48 coterminous United States. (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.)

Corresponding Freeze Climatologies for the last occurrence of 32-degree or 28-degree temperatures in spring are available across the contiguous US from MRCC/VIP. A map of the median date of the last 32-degree occurrence is available on this site.

Across the continental U.S. the typical lengths of the frost-free regions (between the date of the last spring 32-degree temperature and the first32-degree occurrence in fall) range from about 120 days along the Canadian border to about 220 days in Oklahoma and north Texas and over 320 days in southern sections of Florida and California. Mountainous areas provide a complex pattern, with some higher elevations having lengths that are less than 100 days. By accessing the NOWData (NOAA Online Weather Data) feature on the Climate page of your local National Weather Service office, you can find the "first/last dates" for various climate reporting stations around your area.

Historical Events

10 September 1900...Elk Point, SD received 8.00 inches of rain that set a 24-hour maximum precipitation record for the state. (NCDC)
10 September 1919...One of the most intense hurricanes to hit the U.S. swept through Key West, FL. Over 700 people died along the storm's track from the Lesser Antilles to Corpus Christi, TX. (National Weather Service files)
10-11 September 1963...A 24-hour rainfall record for the Northern Hemisphere was set at Paishih, Taiwan as 49.13 inches of rain fell as the result of Typhoon Gloria. (Accord Weather Guide Calendar)
11-12 September 1949...Early snowstorm dumped 7.5 inches on Helena, MT on the 11th, the earliest measurable snow for the city to date, then an additional 22 inches followed the next day. (The Weather Doctor)
11-12 September 1976...Japan's 24-hour rainfall record was set as 44.80 inches of rain fell at Hiso in Tokuhima Prefecture as a result of Typhoon Fran, which also was responsible for 167 deaths in Japan. (Accord Weather Guide Calendar)
11 September 1990...The high temperature at Phoenix, AZ reached 112, the highest ever for the date and for so late in the season. (Intellicast)
11 September 1992...With sustained winds of 145 mph and gusts to 175 mph, category 4 Hurricane Iniki pulverized Kauai. The central pressure central pressure was 27.91 inches of mercury. At the time, this hurricane was the worst storm in recorded history in Hawaii and one of the 10 worst in US history; it caused between $2 billion and $3 billion in damage. (National Weather Service files)
12 September 1987...Peak sustained winds in Hurricane Max reached 155 mph, the highest observed for an Eastern Pacific hurricane. (The Weather Doctor)
13 September 1922...The temperature at El Azizia in Libya soared to 136 degrees to establish a world record at a surface weather station. To make matters worse, a severe ghibi (dust storm) was in progress. (The Weather Channel) (NCDC) [Note: In September 2012, a World Meteorological Organization panel disqualified this world record temperature due to errors made in recording the temperature at that location. The currently recognized world record high temperature is 134 degrees made at Greenland Ranch in Death Valley, CA on 10 July 1913.]
13 September 1988...Hurricane Gilbert smashed into the Cayman Islands, and as it headed for the Yucatan peninsula of Mexico strengthened into a monster hurricane, packing winds of 175 mph. The barometric pressure at the center of Gilbert reached 26.13 inches (888 mb), an all-time record for any hurricane in the Caribbean, Gulf of Mexico, or the Atlantic Ocean. Gilbert covered much of the Gulf of Mexico, producing rain as far away as the Florida Keys. (The National Weather Summary) (Storm Data)
14 September 1937...The mercury soared to 92 degrees at Seattle, WA, a record for September. (The Weather Channel)
14 September 1970...The temperature at Fremont, OR dipped to 2 degrees above zero to equal the state record for September set on the 24th in 1926. (The Weather Channel)
14 September 1987...Barrow, AK received 5.1 inches of snow, a record for September. (Sandra and TI Richard Sanders - 1987)
14 September 1988...Pressure in the eye of Hurricane Gilbert moving across the Caribbean Sea fell to 885 millibars (26.17 inches of mercury), the lowest recorded barometric pressure in the Western Hemisphere. Ultimately, 318 died in seven countries across the Caribbean and Gulf of Mexico.
15 September 1939...The temperature at Detroit, MI soared to 100 degrees to establish a record for September. (The Weather Channel)
15 September 1982...A snowstorm over Wyoming produced 16.9 inches at Lander to establish a 24-hour record for September for that location. (13th-15th) (The Weather Channel)
16 September 1881...Iowa's earliest measurable snow of record fell over western sections of the state. Four to six inches were reported between Stuart and Avoca. (The Weather Channel)
16 September 1964...The temperature at Concord, NH dropped to 27 degrees ending the shortest growing season on record (100 days). (Intellicast)
16 September 1988...Hurricane Gilbert made landfall 120 miles south of Brownsville, TX in Mexico during the early evening. During its life span, Gilbert established an all-time record for the Western Hemisphere with a sea-level barometric pressure reading of 26.13 inches. Winds approached 200 mph, with higher gusts. Gilbert devastated Jamaica and Mexico's Yucatan Peninsula. (The National Weather Summary) (Storm Data) (The Weather Channel)
16 September 2004, Birmingham, Alabama: Birmingham, AL set two all-time records for the city as Hurricane Jeanne crossed the city: Lowest sea level pressure on record, 986.8 millibars (29.14 inches of mercury), and the greatest 24-hour rainfall event on record, 9.75 inches. (The Weather Doctor)
17 September 1829...The Siebold Typhoon, Japan's most catastrophic typhoon, inflicted widespread damage over much of Japan. On the southern island of Kyushu, the storm surge off the Ariake Sea kills 10,000. (The Weather Doctor)

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