Here is my weekly weather quiz question for the last time. What is the “Backwater Effect?” Here is the correct answer. The Backwater Effect is 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 High Pressure Ridge (Shaded “Arch” shape with blue arrows) will slowly migrate across Oregon. Marine clouds cooled us a bit Saturday. We’ll slowly warm up a bit again today. The graphics for days 3-7 show the next frontal system approaching the Pacific Northwest next Sunday. The 4th of July looks bright and dry with temperatures near 80. That’s just about normal.

 

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 31 in the Good category measuring Ozone.

Oakridge: The Air Quality Index is 20 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 30 in the Good category measuring Ozone.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

 

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Advisories:

•  A Health Advisory has been issued for Lake Billy Chinook, located 12 miles west of Madras in Jefferson County. Water monitoring has has confirmed the presence of Blue-green Algae and the toxins they produce. These toxin concentrations ca be harmful to humans and animals. People should avoid swallowing water while swimming or inhaling water droplets as a result of high-speed water activities, such as water skiing or power boating, in areas where blooms are identified. Although toxins are not absorbed through the skin, people who have skin sensitivities may experience a puffy, red rash at the affected area.Drinking water directly from these areas of Lake Billy Chinook at this time is especially dangerous. Oregon public health officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• 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 AM, sunny and a bit warmer this afternoon, partly cloudy tonight,
• AM clouds Monday, mostly sunny in the afternoon, mostly clear Monday night,
• Partly cloudy in the AM, sunny and a bit warmer Tuesday (Independence Day), then clear at night.
• highs 82-85 lows 55-50 warming to 53 Tuesday night.
• Sunny and a bit warmer Wednesday, clear at night,
• Sunny and a bit cooler Thursday, clear Thursday night,
• Sunny and a bit warmer Friday, clear at night,
• Then mostly sunny and a bit cooler Saturday,
• highs 84-82 lows 53-55. (seasonal averages high 79 low 50)

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Eugene-Springfield Pollen Count

Grass………. High (100)

Trees………. Moderate (16)

Last Counted: 6/30/17

Data Courtesy of Oregon Allergy Associates.

 

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Forecast for Roseburg:

• Partly cloudy with patchy AM fog, mostly sunny and a bit warmer this afternoon, mostly clear tonight,
• AM clouds and patchy fog, mostly sunny and a bit cooler Monday, clear Monday night,
• Sunny and a bit warmer Tuesday (Independence Day), then clear at night.
• highs 86-84 warming to 87 Tuesday lows near 58.
• Sunny Wednesday and Thursday, clear both nights,
• Then mostly sunny Friday and Saturday (a bit cooler), mostly clear Friday night.
• highs 87-85 lows 60-58. (seasonal averages high 81 low 55)

 

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

• Mostly cloudy with areas of fog this AM, sunny this afternoon, mostly clear this evening, mostly cloudy with patchy fog late tonight and Monday AM, sunny in the afternoon, mostly clear Monday night,
• Partly cloudy with patchy AM fog, mostly sunny Tuesday afternoon (Independence Day), then mostly clear at night.
• highs near 64 lows 53-55.
• Mostly sunny Wednesday, mostly clear with patchy fog late at night and Thursday AM, mostly sunny in the afternoon, mostly clear with patchy fog at night,
• Partly cloudy with patchy AM fog, mostly sunny Friday afternoon, then partly cloudy Friday night and Saturday.
• highs near 64 lows near 55. (seasonal averages high 64 low 52)

 

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Forecast for the Cascades in Lane County:

• Sunny and a bit warmer today, mostly clear tonight,
• Mostly sunny and a bit warmer Monday, clear Monday night,
• Sunny and a bit warmer Tuesday (Independence Day), then clear at night.
• free air freezing level 16,000 ft. today through Monday night, 16,000 ft. falling to 15,000 ft. Tuesday, then 15,000 ft. Tuesday night.
• highs 76-79 lows 46-48.
• Sunny and a bit cooler Wednesday, clear Wednesday night.
• Sunny and a bit cooler Thursday and Friday, clear both nights,
• Then mostly sunny Saturday.
• free air freezing level 15,000 ft. Wednesday, 15,000 ft. falling to 14,000 ft. Wednesday night, 14,000 ft. Thursday, 14,000 ft. rising to 15,000 ft. Thursday night, then 15,000 ft. Friday through Saturday.
• highs 78-76 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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