Here is my weekly weather quiz question for the last time. What is a “Thalweg?” Here is the correct answer. A Thalweg: In hydrologic terms, the line of maximum depth in a stream. The thalweg is the part that has the maximum velocity and causes cutbanks and channel migration. I’ll have a new weekly weather quiz question for you starting Monday. Please remember to post your answer as a comment by clicking on “no comments /comments” in the upper right hand portion of this page under the caption, then add your comment. The first person to post the correct answer 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 (“Arch” shape in blue arrows) has brought us sunshine and much warmer temperatures. The airflow will increase from the West Sunday cooling us out of the 90s. It looks like a frontal system will be heading our way next Tuesday with very little or no effect on our weather. Another frontal system slides through the Pacific Northwest Thursday. You may just want to check out this year’s Perseid Meteor Shower which peaks through Sunday. It is predicted that you could see up to 200 “shooting stars” per hour from debris from the comet Swift-Tuttle. Best viewing is late at night to before sunrise. Make sure you are out far enough away from the city lights so the sky looks darker and the meteorites will be more easily seen.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 45 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 23 in the Good category measuring Particulate Matter.

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

Data courtesy of Lane Regional Air Protection Agency (LRAPA).

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Advisories:

• A HEAT ADVISORY IS IN EFECT UNTIL 6 PM TODAY FOR THE GREATER PORTLAND METRO AREA, THE CENTRAL WILLAMETTE VALLEY, THE SOUTH WILLAMETTE VALLEY, THE WESTERN COLUMBIA RIVER GORGE AND THE CENTRAL COLUMBIA RIVER GORGE.
• A RED FLAG WARNING FOR STRONG WINDS AND LOW RELATIVE HUMIDITY IS IN EFFECT FROM 3  PM UNTIL 8 PM TODAY FOR THE WESTERN ROGUE BASIN INCLUDING THE ILLINOIS VALLEY AND THE EASTERN ROGUE VALLEY.
• A HEAT ADVISORY IS IN EFFECT UNTIL 7 PM TODAY FOR EASTERN CURRY COUNTY, JOSEPHINE COUNTY AND JACKSON COUNTY.
• A Blue-Green Algae health advisory in effect for Odell Lake in Lane County has been lifted. Water testing has confirmed the presence of blue-green algae and the toxins they produce. 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.
• A Blue-Green Algae health advisory remains in effect for Howard Bay (sometimes called Howards Bay or Howard’s Bay) in Upper Klamath Lake ONLY. 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.

 

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

• Sunny and hot today, clear in this evening, partly cloudy late tonight,
• Mostly sunny and a bit cooler Sunday, mostly clear in the evening, mostly cloudy late Sunday night and Monday AM, mostly sunny and a bit cooler  Monday afternoon, then clear at night.
• highs 97-86 lows near 55.
• Then sunny and a bit warmer Tuesday, Wednesday, Thursday and Friday, clear each night,
• highs 88-93 lows near 55. (seasonal averages high 83 low 51)

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Eugene-Springfield Pollen Count:

Grass………. Low (3)

Trees………. Low (0)

Last Counted: 8/11/16

Data Courtesy of Oregon Allergy Associates.

The Grass and Tree Pollen season is officially over now.

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Forecast for Roseburg:

• Sunny and hot today, clear this evening, partly cloudy late tonight and Sunday AM, sunny but a bit cooler in the afternoon, mostly clear Sunday night,
• Partly cloudy in the AM, sunny Monday afternoon, then clear at night.
• highs 100-92 lows 60-58.
• Sunny Tuesday, Wednesday, Thursday and Friday, clear each night.
• highs 90-94 lows 58-56 warming back to 58 Thursday night. (seasonal averages high 85 low 56)

 

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

• Sunny this afternoon, partly cloudy this evening, cloudy late tonight with areas of fog and patchy coastal drizzle late at night,
• Cloudy with AM patchy drizzle and areas of fog Sunday, sunny in the afternoon, partly cloudy in the evening, mostly cloudy patchy fog late Sunday night,
• Then mostly cloudy with patchy AM coastal fog, sunny Monday afternoon, partly cloudy in the evening, cloudy late Monday night.
• highs near 66 lows near 55.
• Partly cloudy Tuesday through Wednesday, clear in the evening , partly cloudy late Wednesday night through Friday AM, then sunny Friday afternoon.
• highs near 66 lows near 54. (seasonal averages high 65 low 53)

 

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Forecast for the Cascades in Lane County:

• Sunny and a bit warmer today, clear tonight,
• Mostly sunny in the AM, partly cloudy and a bit cooler Sunday afternoon, mostly clear Sunday night,
• Sunny and a bit cooler Monday, then clear at night.
• free air freezing level 15,000 ft. today through Monday night.
• highs 86-77 lows 52-47 warming to 50 Monday night.
• Then sunny and a bit warmer Tuesday, Wednesday, Thursday and Friday, clear each night,
• free air freezing level 15,000 ft. Tuesday through Wednesday, then 16,000 ft. Wednesday night through Friday.
• highs 82-80 warming to 82 Thursday and Friday lows near 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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