From the Weminuche Audubon Society (Jean Zimhelt) via The Pagosa Springs Sun:
Please join the Weminuche Audubon Society on Wednesday, Sept. 16, at 6:30 p.m. for our monthly chapter meeting.
This remote meeting will take place on Zoom. Please check the events list on our website, http://www.weminucheaudubon.org, for a link to the online meeting. All interested parties are welcome.
The topic of this month’s meeting will be the importance of wetlands, particularly those in our Pagosa Springs area. Eighty percent of all wildlife species use wetlands or riparian habitats at some point in their life cycle.
According to the EPA, “More than half of our original wetlands have been drained and converted to other uses.”
Geothermal sources in Pagosa Springs have created unique, warm-water wetlands and con- tribute to the rich diversity of birds we see along the Riverwalk in town.
Our presenter for the evening will be Randy McCormick. Prior to moving to Pagosa Springs, McCormick served as environmental manager at the National Estuarine Research Reserve in Naples, Fla., mandated to protect 110,000 acres of coastal wetlands in the western Everglades. He is a board member of the Weminuche Audubon Society and an active member in Pagosa Wetland Partners, a group of citizens committed to preserving important area wetlands habitats. Find out how you can be involved in this mission.
Many communities in the West are growing, and in some places that’s putting pressure on already scarce water supplies.
That’s the case in northern Colorado, where a proposed set of reservoirs promises to allow small suburbs to keep getting bigger. The project, called the Northern Integrated Supply Project (NISP), has stirred up a familiar debate over how the West grows, and whether water should be a limiting factor.
NISP — with its two new reservoirs, and network of pipelines across a broad sweep of Northern Colorado — is close to being fully permitted, which would pave the way to begin construction of the infrastructure project to satisfy the needs of 15 fast-growing Front Range municipalities and water providers. The project promises to give those communities water to build new homes and businesses — without buying it from farmers.
Glade Reservoir is the proposed body of water that would fill a bathtub-shaped valley north of Fort Collins that currently acts as a straight stretch of Highway 287…
Glade would be one of the Western U.S.’s biggest new reservoirs to come online in the past couple decades. With a more than $1 billion price tag, a project of this size and scale has those who live near the new reservoir and along pipeline routes concerned…
Northern Water, the quasi-governmental agency that moves water through tunnels, canals and reservoirs across a broad swath of Northern Colorado, is pushing for NISP’s construction on behalf of 15 other water providers, mostly small suburbs that have ambitions to grow. The communities of Dacono, Firestone, Eaton, Lafayette, Windsor and Severance are all participants in the project, among others…
NISP is getting close to the end of a federal, state and local permitting process. Since first formally submitting for permits in 2004, the project has jumped through regulatory hurdles like a federal environmental impact statement, a water quality certification from the Colorado Department of Public Health and Environment, and a 1041 permit from Larimer County. The 1041 permit gives local governments in Colorado some oversight authority on large infrastructure projects within their boundaries…
[The Larimer County] voted to recommend the 1041 permit to the board of county commissioners, which then approved on a 2-1 vote the permit for the project…
The town of Erie, a rapidly growing community in Boulder County about a half hour from Boulder and north Denver, would be the largest recipient of NISP water…
After more than 15 years of permitting, countless hours of negotiation over the project’s mitigation plans, and millions of dollars spent on studies, surveys and outreach, the agency pushing for NISP, Northern Water, says it has made significant changes to the planned project in order to help the already overtaxed Poudre River. Opponents say the project will only hurt, not help.
The Cache la Poudre River, where NISP would draw water for its largest reservoir, is often referred to as a “working river.” It provides drinking water for cities and irrigation water for farms. During the summer months it’s popular with kayakers, tubers and anglers. It’s also home to fish, birds and other wildlife…
The project still needs one more federal approval from the Army Corps of Engineers before it’s considered to be fully permitted, and ready to head into design and construction phases.
La Niña conditions were present in August, and there’s a 75% chance they’ll hang around through the winter. NOAA has issued a La Niña Advisory. Just how did we arrive at this conclusion, and what does a La Niña winter portend? Read on to find out!
Checking the boxes
Let’s revisit our La Niña decision tree.
The answer to the first question, “Is the monthly Niño3.4 sea surface temperature anomaly equal to or less than -0.5°C?” is an easy “yes.” August’s value was -0.6°C according to our most consistent sea surface temperature dataset, the ERSSTv5 (though that is not the only SST dataset we monitor). For a quick refresher, the Niño3.4 sea surface temperature anomaly is the difference from the long-term average temperature of the surface of the Pacific Ocean in the Niño3.4 region. In this case, the long-term average is 1986-2015.
The second step is “Do you think it will stay more than half a degree cooler than average for the next several months?” and again, the answer is “yes.” Most of the dynamical computer models predict that the sea surface temperature will remain below the La Niña threshold of -0.5°C through the winter.
Now, on to the critical third step: “Is the atmosphere showing signs of a response to the cooler-than-average sea surface?” Another “yes!” La Niña intensifies the contrast between the warm far western Pacific and much cooler eastern Pacific, and so La Niña’s atmospheric response is a strengthening of the Walker circulation. This large-scale circulation pattern is characterized by air rising over the very warm waters of the far western Pacific and Indonesia, traveling eastward high in the atmosphere, sinking over the eastern Pacific, and traveling back westward near the surface. (Creating the trade winds—more on those in last month’s post.)
When the Walker circulation is stronger than average, the trade winds are stronger, which we observed in the end of August and early September. More rising air over the far western Pacific means lower air pressure, while descending air over the eastern Pacific means higher air pressure; the contrast between these two arms of the Walker circulation is measured using the Southern Oscillation Index and the Equatorial Southern Oscillation Index. Both indexes were positive in August, at 1.1 and 1.0 respectively. These values, which are in the top 20% of the 1950–present record, indicate a stronger-than-average Walker circulation.
La Niña impacts
La Niña’s altered atmospheric circulation over the Pacific Ocean affects global weather and climate. While every ENSO event (and every winter!) is different, La Niña can make certain outcomes more likely. This includes more rain than average through Indonesia, cooler and wetter weather in southern Africa, and drier weather in southeastern China, among other impacts.
One important global impact of La Niña is its effect on the Atlantic hurricane season. La Niña reduces wind shear—the change in winds between the surface and the upper levels of the atmosphere—allowing hurricanes to grow. The likelihood of La Niña was factored into NOAA’s August outlook for the Atlantic hurricane season, which favored an “extremely active” season. As of September 8th, we have seen 17 named storms so far this season, and the forecast is for a total of 19-25 named storms (the hurricane season ends on Nov. 30th).
La Niña affects US weather through its impact on the Asia-North Pacific jet stream, which is retracted to the west during a La Niña winter and often shifted northward of its average position. Tom wrote a great explanation of the La Niña/jet stream mechanics and impacts here. Generally, La Niña winters in the southern tier of the US tend to be warmer and drier, while the northern tier and Canada tend to be colder. Official seasonal outlooks are available from the Climate Prediction Center, and Nat will be writing about CPC’s winter outlook for the blog in November.
We have a bunch of information on La Niña impacts here on the ENSO Blog! In the early stages of our last La Niña, 2018–2019, Tom mapped out the temperature and precipitation during every La Niña winter on record. Also, guest posts have covered La Niña’s effect on snow in the US, a potential link with tornado season, and how La Niña can interact with other climate variability patterns. And of course, we’ll be here every month, updating you on how ENSO conditions are evolving.
August 2020 will be remembered for its extreme heat and violent weather: The U.S. endured heat waves, hurricanes, a devastating derecho and raging wildfires out West.
Meteorological summer — June through August’s end — was a standout: It ranked 4th hottest and in the driest one-third of all summers in the historical record.
Here are more highlights from NOAA’s latest monthly U.S. climate report:
Climate by the numbers
The average temperature for August across the contiguous U.S. was 74.7 degrees F (2.6 degrees above the 20th-century average) and ranked third-hottest August on record.
Arizona, California, Colorado, Nevada, New Mexico and Utah each had their warmest August on record. In particular, Phoenix, Arizona, had its hottest month ever recorded, with an average temperature of 99.1 degrees F.
Also on August 16, Death Valley in California reported a high temperature of 130 degrees F. If verified, this temperature would be the hottest August temperature on record for the U.S.
The average August precipitation for the contiguous U.S. was 2.35 inches (0.27 of an inch below average), which put the month in the driest third of the 126-year record.
Arizona, Nebraska and Utah ranked driest on record for August, while New Mexico and Iowa ranked second and third driest on record, respectively.
Year to date & meteorological summer
The average U.S. temperature for the year to date (YTD, January through August) was 56.3 degrees F, 2.4 degrees above the 20th-century average. It ended as the 7th-warmest in the YTD record.
The contiguous U.S. has seen 21.64 inches of precipitation for the YTD (0.93 of an inch above the long-term average), placing it in the wettest third of record.
For meteorological summer (June through August), the average temperature for the contiguous U.S. was 73.6 degrees F — 2.2 degrees above the average. Summer 2020 ended with the ranking of 4th-hottest summer on record.
The precipitation total for summer was 7.99 inches (0.33 of an inch below average), which ranked in the driest third of the record.
More notable climate and extreme events
Two Atlantic hurricanes made landfall.
Hurricane Isaias struck North Carolina on August 4 and quickly accelerated up the East Coast, bringing widespread damage and power outages across New York, New Jersey and Pennsylvania.
Hurricane Laura made landfall on August 27 in southwest Louisiana with 150-mph winds. Laura tied the 1856 Louisiana hurricane for having the strongest land-falling winds on record for the state.
Wildfires blazed. Numerous wildfires burned hundreds of thousands of acres across the West. Lightning from unusual summer thunderstorms sparked the second-,third-, and fourth-largest fires on record in California, while the Pine Gulch Fire, near Grand Junction, Colorado, became the state’s largest wildfire in state history.
A devastating derecho swept through. On August 10, a line of severe thunderstorms with widespread winds of more than 100 mph, known as a derecho, raced 700 miles across the central U.S. from Iowa to Ohio and brought significant damage to crops and infrastructure.