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Check out my latest Eugene Daily News Weather Or Not Column I Wonder How The Dam Thing Works and my new Feature Story How Medical Science Changed My Life.

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We have a winner!

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Congratulations to Josh Foster for being the first person to post the correct answer my new weekly weather quiz question. Here is the question again. Please define “a warm occlusion” and no it has nothing to do with a dental overbite. Here is Josh’s correct answer: In a warm occlusion, the air mass overtaking the warm front is not as cool as the cold air ahead of the warm front, and rides over the colder air mass while lifting the warm air. There are both warm and cold occluded fronts. Josh wins a week of free personalized weather forecasts tailored to his needs. I’ll have a new weekly weather quiz question starting next 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. The answer has to be a comment to win. An email answer will not count. Good luck.

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Advisories:

There is a Blue-Green Algae warning that continues for Dexter Reservoir and Dorena Reservoir, and now Fern Ridge Reservoir has been added to the list. Water monitoring has confirmed the presence of blue-green algae that can produce toxins, state public health officials said. The algae levels are likely associated with dangerous cyanotoxin concentrations in the water that can be harmful to humans and animals. Swallowing or inhaling water droplets, as well as skin contact with water, should be avoided according to the authorities.

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An upper level low (“U” shape with blue arrows) along the coast will continue to send disturbances our way including this frontal system that is moving toward the Pacific Northwest. The front will fall apart before it gets to us. We will warm up a bit then cool back down again. Yet another frontal system will move into Oregon over the weekend.

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The Grass Pollen Count is listed as Absent at 0 and Tree pollen is Low at 2 as of 8/27/13 according to Oregon Allergy Associates.

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

• Partly cloudy this evening, mostly cloudy with a slight (20%) chance of showers late tonight.
• Mostly cloudy Wednesday AM, partly cloudy in the afternoon and evening, mostly cloudy with a slight (20%) chance of showers late Wednesday night.
• Cloudy Thursday AM, a mix of clouds and sun with a good (50%) chance of showers in the afternoon, mostly cloudy with a slight (20%) chance of showers Thursday night.
• A mix of clouds and sun Friday, partly cloudy in the evening, then mostly cloudy late Friday night.
• lows 56-60 cooling to 56 Friday night highs 83-80.
• A mix of clouds and sun Saturday, mostly cloudy Saturday night.
• Mostly cloudy with a slight (20%) chance of showers Sunday afternoon through Monday (Labor Day), then mostly cloudy with a slight (20%) chance of showers Monday night and Tuesday.
• highs 80-74 warming to 77 Tuesday lows near 54. (seasonal averages high 82 low 50)

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Forecast for the Umpqua Basin including Roseburg:

• Clear this evening, mostly cloudy late tonight and Wednesday, partly cloudy in the evening, mostly cloudy late Wednesday night and Thursday AM, partly cloudy with a (30%) chance of rain Thursday afternoon, partly cloudy in the evening and mostly cloudy with a slight (20%) chance of showers late at night.
• Partly cloudy with a slight (20%) chance of showers Friday afternoon, then just mostly cloudy Friday night.
• lows 60-62 highs 86-83.
• Mostly cloudy  Saturday, partly cloudy in the evening, mostly cloudy with a slight (20%) chance of showers late Saturday night.
• Mostly cloudy with a slight (20%) chance of showers Sunday through Monday (Labor Day), partly cloudy in the evening and mostly cloudy with a slight (20%) chance of showers late Monday night.
• Mostly cloudy with a slight (20%) chance of showers Tuesday AM, then partly cloudy Tuesday afternoon.
• highs 84-78 warming to near 80 Tuesday lows 59-55. (seasonal averages high 83 low 55)

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Forecast for the South Oregon Coast including Coos Bay and North Bend:

• Partly cloudy this evening, mostly cloudy with a slight (20%) chance of coastal rain late tonight (under 0.10 in. of rain possible) through Wednesday night while a slight (20%) chance of rain inland late Wednesday night (under 0.10 in. of rain possible).
• Mostly cloudy with a (40%) chance of rain Thursday (under 0.01 in. of rain possble),  a slight (20%) chance of coastal showers late Thursday night while partly cloudy with a slight chance of inland showers in the evening then mostly cloudy late Thursday night.
• Mostly cloudy with a slight (20%) chance of showers  Friday, then just mostly cloudy Friday night.
• lows 57-59 cooling to 56 Friday night highs 70-68.
• Mostly cloudy Saturday, a slight (20%) chance of showers late Saturday night.
• Mostly cloudy with a (30%) chance of showers Sunday and Sunday night. Mostly cloudy with a slight (20%) chance of showers Monday (Labor Day) through Tuesday.
• highs 68-64 lows near 55. (seasonal averages high 66 low 53)

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Forecast for the Cascades of Lane County:

• Partly cloudy tonight, partly cloudy with a slight (20%) chance of showers Wednesday afternoon and evening, partly cloudy late at night.
• A mix of clouds and sun with a slight (20%) chance of rain Thursday, partly cloudy  with a slight (20%) chance of showers Thursday night.
• Then just partly cloudy Friday and Friday night.
• free air freezing level 12,000 ft. tonight, snow level above 8,000 ft. Wednesday through Thursday night, free air freezing level 12,000 ft. Friday, then 13,000 ft. Friday night.
• lows near 47 highs 73-69.
• A mix of clouds and sun Saturday, partly cloudy Saturday night.
• A mix of clouds and sun with a slight (20%) chance of showers Sunday, mostly cloudy with a slight (20%) chance of showers Sunday night.
• A mix of clouds and sun with a (40%) chance of showers Monday (Labor Day), mostly cloudy with a slight (20%) chance of showers at night, then a mix of clouds and sun with a slight (20%) chance of showers Tuesday.
• free air freezing level 13,000 ft. Saturday, 13,000 ft. falling to 12,000 ft. late Saturday night, then snow level above 8,000 ft. Saturday through Monday.
• highs 69-62 warming to 65 Tuesday lows 46-43.

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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 Eugene Daily News.com.

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