Here is my weekly weather quiz question for the last time. What is the “Backwater Effect?” Here is the correct answer. The Backwater Effect in hydrologic terms, the effect which a dam or other obstruction has in raising the surface of the water upstream from it. I’ll have a new weekly weather quiz question for you starting Monday. The first person to post the correct answer as a comment on this page will win a week of free personalized weather forecasts tailored to your needs.  Good luck.

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The graphics for days 1-3 show a frontal system moving through the Pacific Northwest Sunday. An Upper Level Low Pressure Trough (Shaded “U”shape with blue arrows) is helping to change our weather pattern.  Onshore airflow will keep us cooler with the benefit of cleaner air. The graphics for days 3-7 show a frontal system moving through Oregon Saturday and Sunday.

Note: The Perseid Meteor Shower peaks this weekend from tonight through Sunday night. The moon will be about three quarters full so that will make viewing more difficult. Here cloud cover could be a problem as well as any residual smokey haze. Best viewing time will be after midnight and before dawn each night. Get away from the city lights and the sky won’t have the glow of city lights to obstruct your view.

 

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 27 in the Good category measuring Ozone.

Oakridge: The Air Quality Index is 33 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 25 in the Good category measuring Ozone.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

 

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Advisories:

• A RED FLAG WARNING IS IN EFFECT FOR ABUNDANT LIGHTNING AND OUTFLOW WINDS UNTIL 11 PM TONIGHT FOR THE CENTRAL MOUNTAINS OF OREGON, THE NORTHERN BLUE MOUNTAINS OF OREGON, THE SOUTHERN BLUE AND STRAWBERRY MOUNTAINS OF OREGON, THE CENTRAL BLUE MOUNTAINS OF OREGON, THE KLAMATH BASIN, THE FREMONT-WINEMA NATIONAL FOREST, THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE COUNTY, AND WESTERN HARNEY COUNTY.
• The Oregon Health Authority issued a Health Advisory today for Willow Creek Reservoir, located just east of the town of Heppner in Morrow County. Water monitoring has confirmed the presence of blue-green algae and the toxins they produce in the reservoir. These toxin concentrations can be harmful to humans and animals. People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue-green or brownish-red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur is discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified, or an advisory issued, can expose people to the toxins being produced. Although toxins are not absorbed through the skin, people who have skin sensitivities that come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Willow Creek Reservoir at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• The Oregon Health Authority has updated the Health Advisory issued July 28 for Howard Bay (also known locally as Howards Bay or Howard’s Bay), located in the southwest corner of Upper Klamath Lake, to include Shoalwater Bay to the north. These areas of Upper Klamath Lake are located off Oregon Route 140, 15 miles west of Klamath Falls in Klamath County. Water monitoring has confirmed the presence of blue-green algae and the toxins they produce in Howard Bay. These toxin concentrations can be harmful to humans and animals. People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue green or brownish red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur is discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified, or an advisory issued, can expose people to the toxins being produced. Although toxins are not absorbed through the skin, people who have skin sensitivities that come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Howard Bay and Shoalwater Bay at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• The Oregon Health Authority issued Health Advisory for Agency Lake, located just north of Klamath Falls along U.S. Highway 97 in Klamath County. Water monitoring has confirmed the presence of blue-green algae and the toxins they produce in the lake. These toxin concentrations can be harmful to humans and animals. People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue green or brownish red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur is discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified, or an advisory issued, can expose people to the toxins being produced. Although toxins are not absorbed through the skin, people who have skin sensitivities that come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Agency Lake at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• The Oregon Health Authority issued a Health Advisory today for Willow Creek Reservoir, located just east of the town of Heppner in Morrow County. Water monitoring has confirmed the presence of blue-green algae and the toxins they produce in the reservoir. These toxin concentrations can be harmful to humans and animals. People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue green or brownish red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur is discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified, or an advisory issued, can expose people to the toxins being produced. Although toxins are not absorbed through the skin, people who have skin sensitivities that come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Willow Creek Reservoir at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• The Oregon Health Authority issued a Health Advisory for Coffenbury Lake, located at Fort Stevens State Park about five miles northwest of US-101 ALT, Northwest Ridgefield Road near Warrenton in Clatsop County. Water monitoring has confirmed the presence of blue-green algae that can produce toxins in Coffenbury Lake. These blue-green algae levels are likely to be associated with dangerous cyanotoxin concentrations in the water that can be harmful to humans and animals.  People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue-green or brownish-red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur are discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified or an advisory issued, can expose people to the toxins that can be produced. Although toxins are not absorbed through the skin, people with skin sensitivities who come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Coffenbury Lake at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• The Oregon Health Authority has updated the Health Advisory issued June 30 for Lake Billy Chinook, located about 12 miles west of Madras in Jefferson County. The update lifts the advisory on those areas of the Deschutes and Crooked River of Lake Billy Chinook arms affected by the advisory, and confines the advisory on the Metolius Arm to Perry South Cove. Water monitoring has confirmed that the level of blue-green algae toxins are below guideline values for human exposure. However, OHA recommends that people remain cautious when using the lake, particularly with pets because toxins are still well above the very low exposure levels established for dogs.
• A Permanent Health Advisory remains in effect for the South Umpqua River and Lawson Bar. Pools in the bedrock along the rivers edge are known to develop Blue-green Algae (cyanobacterial) blooms that can be harmful to pets and people if accidental ingestion occurs. Signs have been posted along several access areas along the river.

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Forecast for the Southern and lower Mid Willamette Valley including Eugene-Springfield and Albany-Corvallis:

• Partly cloudy this evening, mostly cloudy with a good (50%) chance of rain late tonight (under 0.10 in. of rain possible),
• Cloudy with a good (50%) chance of AM showers (under 0.10 in. of rain possible), a mix of clouds and sun Sunday afternoon, mostly clear at night,
• AM clouds and sun, mostly sunny and a bit warmer Monday afternoon, mostly clear Monday night,
• Mostly sunny and a bit warmer Tuesday, then partly cloudy at night.
• lows 57-50 warming to 52 Tuesday night highs 75-82.
• Partly cloudy in the AM, mostly sunny and a bit warmer Wednesday, partly cloudy at night,
• Partly cloudy Thursday AM, mostly sunny and a bit warmer in the afternoon, mostly clear Thursday night,
• Partly cloudy Friday AM, mostly sunny and a bit warmer in the afternoon, mostly clear at night,
• Mostly sunny in the AM, then partly cloudy and a bit cooler Saturday afternoon.
• highs 87-89 cooling back to 87 Saturday lows near 55. (seasonal averages high 83 low 51)

 

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Eugene-Springfield Pollen Count

Grass………. Low (2)
Trees………. Low (3)
Last Counted: 8/10/17
Data Courtesy of Oregon Allergy Associates.
Note: It would seem the pollen season is over.

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Forecast for Roseburg:

• Partly cloudy this evening, mostly cloudy with a slight (20%) chance of isolated showers late tonight,
• Mostly cloudy with a (30%) chance of AM showers, mostly cloudy and a bit cooler Sunday afternoon (under 0.10 in. of rain possible), partly cloudy in the evening, mostly cloudy late Sunday night,
• AM clouds, sunny and a bit warmer Monday afternoon, mostly clear at night,
• Mostly sunny and a bit warmer Tuesday, then mostly clear at night.
• lows 58-54 warming to 54 Tuesday night highs 79-85.
• Mostly sunny and a bit warmer Wednesday and Thursday, mostly clear both nights,
• Mostly sunny Friday, mostly clear at night,
• Then sunny Saturday.
• highs 88-94 cooling to 82 Saturday lows 57-60. (seasonal averages high 86 low 56)

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Forecast for The South Oregon Coast Including Coos Bay and North Bend:

• Mostly cloudy with a slight (20%) chance of scattered coastal showers late tonight while partly cloudy this evening and mostly cloudy with isolated inland showers late tonight (under 0.10 in. of rain possible),
• Mostly cloudy with a (30%) chance of scattered AM showers (under 0.10 in. of rain possible), just mostly cloudy Sunday afternoon and at night,
• AM clouds with patchy coastal fog Monday, sunny in the afternoon, partly cloudy in the evening, mostly cloudy late Monday night,
• Mostly cloudy with patchy fog in the AM, sunny and a bit warmer Tuesday afternoon, then partly cloudy Tuesday night.
• lows 56-52 highs 63-66  cooling back to 63 Tuesday.
• Partly cloudy and a bit warmer Wednesday through Thursday night,
• AM clouds, sunny and a bit cooler Friday, clear in the evening, partly cloudy at night,
• Then AM clouds and mostly sunny Saturday.
• highs 68-65 lows near 55. (seasonal averages high 65 low 53)

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Forecast for the Cascades in Lane County:

• Clear this evening, partly cloudy late tonight,
• Mostly cloudy with a good (50%) chance of AM showers, mostly cloudy with a slight (20%) chance of showers Sunday afternoon, becoming mostly clear Sunday night,
• Mostly sunny and a bit warmer Monday afternoon, mostly clear at night,
• Sunny and a bit warmer Tuesday, then mostly clear Tuesday night.
• free air freezing level 14,000 ft. tonight, snow level above 8,000 ft. Sunday, free air freezing level 13,000 ft. Sunday night, 12,000 ft. rising to 13,000 ft. Monday, 13,000 ft. Monday night, 13,000 ft. rising to 15,000 ft. Tuesday, then 15,000 ft. Tuesday night.
• lows 50-45 highs 63-69.
• AM sun, a mix of clouds and sun and a bit warmer Wednesday afternoon, partly cloudy at night,
• Mostly sunny and a bit warmer Thursday and Friday, mostly clear both nights,
• Then mostly sunny and a bit cooler Saturday.
• free air freezing level 15,000 ft. rising to 16,000 ft. Wednesday afternoon, 16,000 ft. Wednesday night through Thursday night, 16,000 ft. falling to 15,000 ft. Friday, then 16,000 ft. Friday night and Saturday.
• highs 75-78 cooling back to 78 Saturday lows 48-50.

 

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**Because weather forecasting is a combination of science, intuition, and timing there can be no absolute guarantees that individual forecasts will be 100% accurate. Nature is in a constant state of flux and sudden unexpected weather events can happen.

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Get your local Eugene-Springfield and Lane County news on-line at eugenedailynews.com.

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