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

Note: The Perseid Meteor Shower peaks this weekend from tonight. The moon will be about three quarters full so that will make viewing more difficult. Best viewing time will be after midnight and before dawn. 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 17 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 11 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 14 in the Good category measuring Ozone.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

 

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Advisories:

• 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:

• Mostly cloudy this evening, partly cloudy late tonight and Monday AM, mostly sunny and warmer in the afternoon and Tuesday, mostly clear both nights,
• Mostly sunny and a bit warmer Wednesday, then partly cloudy Wednesday night.
• lows 52-49 warming to 55 Wednesday night highs 79-84.
• Mostly sunny and a bit warmer Thursday and Friday, mostly clear both nights,
• Mostly sunny and a bit cooler Saturday, partly cloudy at night,
• Mostly sunny in the AM, then partly cloudy Sunday afternoon.
• highs 85-87 cooling back to 85 Sunday lows near 53. (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:

• Mostly cloudy tonight and Monday AM, sunny and a bit warmer Monday afternoon and Tuesday, mostly clear both nights,
• Mostly sunny and a bit warmer Wednesday, then mostly clear at night.
• lows 56-53 warming to 57 Wednesday night highs 82-87.
• Mostly sunny and a bit warmer Thursday, Friday, and Saturday, mostly clear each night,
• Sunny Sunday AM, then partly cloudy and a bit cooler in the afternoon.
• highs 89-92 cooling to 88 Sunday lows near 58. (seasonal averages high 85 low 56)

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

• Mostly cloudy with patchy coastal fog late tonight and Monday AM, sunny and a bit cooler in the afternoon, clear in the evening, mostly cloudy with patchy coastal fog late Monday night,
• Mostly cloudy with patchy coastal fog in the AM, sunny and a bit warmer Tuesday afternoon, mostly clear in the evening, mostly cloudy late Tuesday night,
• Patchy AM fog, partly cloudy and a bit warmer Wednesday with patchy lingering fog, then partly cloudy with patchy fog late Wednesday night.
• lows near 55 highs 66-72.
• Patchy AM and late night fog Thursday through Friday, then partly cloudy Friday night through Sunday night.
• highs 72-65 lows near 55. (seasonal averages high 65 low 53)

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Forecast for the Cascades in Lane County:

• Mostly cloudy this evening with a slight (20%) chance of showers, becoming partly cloudy late tonight,
• Mostly sunny and a bit warmer Monday, Tuesday, and Wednesday (a bit warmer), mostly clear each night.
• snow level above 8,000 ft. this evening, free air freezing level 12,000 ft. rising to 13,000 ft. Monday, 13,000 ft. Monday night, 13,000 ft. rising to 14,000 ft. Tuesday afternoon, 14,000 ft. Tuesday night,  15,000 ft. rising to 16,000 ft. Wednesday afternoon, 16,000 ft. falling to 15,000 ft. Wednesday night.
• lows 45-48 highs 67-72.
• Mostly sunny and a bit warmer Thursday, clear at night,
• Sunny and a bit warmer Friday, mostly clear Friday night,
• Mostly sunny and a bit cooler Saturday, mostly clear at night,
• Mostly sunny Sunday AM, then partly cloudy and a bit cooler in the afternoon.
• free air freezing level 15,000 ft. rising to 16,000 ft. Thursday, 16,000 ft. falling to 15,000 ft. Thursday night, 15,000 ft. falling to 14,000 ft. Friday, 14,000 ft. rising to 15,000 ft. Friday night, then 15,000 ft. Saturday through Sunday.
• highs 76-73 lows 50-48.

 

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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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