Here is my weekly weather quiz question for the last time. What is  a “Back-Building Thunderstorm?” Here is the correct answer. Back-building Thunderstorm is a thunderstorm in which new development takes place on the upwind side (usually the west or southwest side), such that the storm seems to remain stationary or propagate in a backward direction.  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) has taken over control of the Pacific Northwest weather for a while bringing sunshine and even warmer temperatures. The graphics for days 1-3 show a frontal system that will move through Monday night into Tuesday. The graphics for days 3-7 a frontal system approaching the Oregon coast next Sunday.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 10 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 12 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 2 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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Advisories:

• A Health Advisory HAS BEEN LIFTED  for South Tenmile Lake, located 10 miles north of North Bend in Coos County. The blue-green algae bloom is no longer present in the Coleman Arm of South Tenmile Lake. However, the Oregon Health Authority recommends that people continue to be cautious with their pets in the lake because toxins are still above the very low exposure levels established for dogs.
• A Health Advisory has been issued  for the water around Eagle Ridge County Park on Upper Klamath Lake. The park is located off Highway 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 this area of Upper Klamath Lake. These toxin concentrations can be harmful to humans and animals.
• A Health Advisory HAS BEEN LIFTED for Detroit Lake, located 46 miles SE of Salem in Marion County. Water monitoring has confirmed the level of blue-green algae toxins  in Detroit Lake are below guideline values for humans. However, the Oregon Health Authority recommends that people continue to be cautious with their pets in the lake because toxins are still 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 clear tonight,
• Partly cloudy in the AM, mostly sunny Monday afternoon, partly cloudy at night,
• Partly cloudy a bit cooler Tuesday and Tuesday night,
• Mostly sunny and a bit cooler Wednesday, then mostly clear at night.
• lows 56-47 highs 87-75.
• Mostly sunny Thursday, clear at night,
• Mostly sunny and a bit warmer Friday and Saturday, clear both nights,
• Then sunny Sunday.
• highs 75-86 lows 48-52. (seasonal averages high 74 low 48)

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Eugene-Springfield Pollen Count:

Grass………. Moderate (9)

Trees………. Moderate (85)

Last Counted: 6/16/17

Data Courtesy of Oregon Allergy Associates.

 

 

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Forecast for Roseburg:

• Mostly clear tonight,
• Partly cloudy Monday AM, sunny and a bit warmer in the afternoon, mostly clear in the evening, partly cloudy Monday night,
• Partly cloudy and a bit cooler Tuesday and in the evening, mostly clear at night,
• Sunny and a bit cooler Wednesday, then clear at night.
• lows 62-52 highs 90-80.
• Sunny but a bit warmer Thursday, clear Thursday night,
• Sunny and a bit warmer Friday and Saturday, clear at night,
• Then mostly sunny and a bit cooler Sunday.
• highs 83-96 cooling to 92 Sunday lows 50-54. (seasonal averages high 76 low 52)

 

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

• Mostly clear this evening, partly cloudy late tonight,
• Mostly cloudy Monday morning, sunny and a bit warmer in afternoon, partly cloudy in the evening, mostly cloudy late Monday night,
• Partly cloudy and a bit cooler Tuesday and in the evening, mostly clear Tuesday night,
• Mostly sunny and a bit cooler Wednesday, then clear Wednesday night.
• lows 58-52 highs 66-64.
• Sunny and a bit warmer Thursday through Saturday, clear each night,
• Then mostly sunny and a bit cooler Sunday.
• highs 65-72 cooling to 68 Sunday lows 52-55. (seasonal averages high 62 low 51)

 

 

 

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Forecast for the Cascades in Lane County:

• Clear tonight,
• Sunny and a bit warmer Monday, partly cloudy Monday night and Tuesday AM, mostly sunny and a bit cooler in the afternoon, mostly clear Tuesday night,
• Mostly sunny and a bit warmer Wednesday, then clear Wednesday night.
• free air freezing level 16,000 ft. tonight through Tuesday, 15,000 ft. falling to 15,000 ft. Tuesday night, 14,000 ft. rising to 15,000 ft. Wednesday, then 15,000 ft. Wednesday night.
• lows 53-42 highs 79-70 warming to 72 Wednesday.
• Sunny and a bit warmer Thursday and Friday, clear each night,
• Sunny and a bit warmer Saturday, clear at night,
• Then sunny and a bit warmer Sunday.
• free air freezing level  15,000 ft. falling to 14,000 ft. Thursday, 14,00 ft. Thursday night and Friday, 14,000 ft. rising to 15,000 ft. Friday night, 15,000 ft. Saturday afternoon and Saturday night, then 15,000 ft. falling to 14,000 ft. Sunday.
• highs 72-78 lows 42-48.

 

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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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