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 warmed up a bit again today. An Upper Level Low Pressure Trough (Shaded “U” shape with blue arrows) moves up toward the coast allowing for more inland warming. The graphics for days 3-7 show the next frontal system approaching the Pacific Northwest and trying to move in Tuesday night into Wednesday. The 4th of July still looks bright and dry with temperatures in the mid 80s. That’s a bit above normal.

 

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 34 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 34 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:

• Clear this evening, partly cloudy late tonight and Monday AM, mostly sunny in the afternoon, mostly clear Monday night,
• Sunny and a bit warmer Tuesday (Independence Day), clear at night,
• Sunny and warm Wednesday, clear in the evening, then partly cloudy late Wednesday night.
• lows 55-50 warming back to 55 Wednesday night highs 82-87.
• Partly cloudy Thursday AM, sunny and a bit cooler in the afternoon, clear in the evening, partly cloudy late Thursday night and Friday AM, mostly sunny and a bit cooler in the afternoon, clear at night,
• Mostly sunny  Saturday, then partly cloudy Saturday night and Sunday.
• highs 85-82 lows 55-53. (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:

• Mostly clear tonight,
• AM clouds and patchy fog, sunny and a bit warmer Monday afternoon, clear at night,
• Partly cloudy in the AM, sunny and a bit warmer Tuesday afternoon (Independence Day), clear at night,
• Mostly sunny with a slight (20%) chance of thunderstorms and a slight bit cooler Wednesday, then mostly clear with a slight (20%) chance  of thunderstorms Wednesday night.
• lows near 58 highs 84-87 cooling to 85 Wednesday.
• Sunny and a bit warmer Thursday, clear at night,
• Mostly sunny Friday and Saturday (a bit cooler), mostly clear Friday night, partly cloudy Saturday night,
• Then partly cloudy and a bit cooler Sunday.
• highs 87-82 lows 60-57. (seasonal averages high 81 low 55)

 

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

• Partly cloudy this evening, mostly cloudy with patchy coastal fog late tonight while patchy inland fog late tonight,
• Mostly cloudy with patchy fog Monday AM, sunny in the afternoon, mostly clear in the evening, partly cloudy late Monday night and breezy (Wind: N 15-25 mph at the shore decreasing to N 10-15 mph late at night while N 10-15 mph inland decreasing to 5 mph late Monday night),
• Mostly cloudy with patchy AM coastal fog, sunny Tuesday afternoon (Independence Day),  clear in the evening, partly cloudy late at night,
• Sunny Wednesday, mostly clear with patchy fog late Wednesday night.
• lows near 55 highs near 64.
• Partly cloudy with patchy fog 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 through Sunday.
• highs near 64 lows near 55. (seasonal averages high 64 low 52)

 

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Forecast for the Cascades in Lane County:

• Mostly clear tonight,
• Sunny and a bit warmer Monday, clear Monday night,
• Mostly sunny and a bit warmer Tuesday (Independence Day), mostly clear at night,
• Sunny Wednesday, then mostly clear Wednesday night.
• free air freezing level 16,000 ft. tonight, 15,000 ft. Monday, 16,000 ft. Monday night, then 15,000 ft. Tuesday through Wednesday night.
• lows 45-50 highs 76-80.
• Sunny Thursday and Friday (a bit cooler ), clear both nights,
• Sunny and a bit cooler Saturday, mostly clear at night,
• Then partly cloudy Sunday.
• free air freezing level 15,000 ft. Thursday and Thursday night, 15,000 ft. rising to 16,000 ft. Friday, then 16,000 ft. Friday night through Sunday.
• highs 80-75 lows 52-48.

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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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