Here is my weekly weather quiz question for the last time. What is “Attenuation?” Here is the correct answer. Attenuation refers to the reduction of the radar beam power due to the reflection or absorption of energy when it strikes a target. The greatest attenuation occurs when the radar beam goes through very heavy rain. I’ll have a new 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 Low Pressure Trough (Shaded “U” shape with blue arrows) is moving out of the Gulf of Alaska to keep the rain chances with us. The graphics for days 1-3 show the next frontal system pushing through Oregon Tuesday. The graphics for days 3-7 show a frontal system approaching the Pacific Northwest toward the end of the week.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 9 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 10 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 0 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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Home Wood Heating Advisory:

Eugene-Springfield: GREEN – Burning is Allowed.

Oakridge: GREEN – Burning is Allowed.

*Note: Pellet stoves may be used anytime if they produce no visible emissions.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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Advisories:

• 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 with a slight (20%) chance of showers tonight (under 0.10 in. of rain possible),
• Mostly cloudy with a slight (20%) chance of rain Monday afternoon (under 0.10 in. of rain possible), rain Monday night (0.50 in. of rain possible) and Tuesday AM, showers with a slight (20%) chance of thunderstorms and a bit cooler Tuesday afternoon (0.25 in. of rain possible), a good (50%) chance of showers and a slight (20%) chance of evening thunderstorms, a good (50%) chance of showers late Tuesday night (under 0.10 in. of rain possible),
• Mostly cloudy with a (30%) chance of AM showers, a bit warmer with a slight (20%) chance of showers Wednesday afternoon, partly cloudy with a slight (20%) chance of evening, showers, then just partly cloudy late at night.
• lows 42-47 cooling to 37 Wednesday night highs 58-55 warming to 62 Wednesday.
• Partly cloudy and a bit warmer Thursday and Thursday night,
• Mostly sunny and a bit warmer Friday, partly cloudy Friday night and Saturday AM, mostly sunny and a bit warmer in the afternoon, mostly clear Saturday night,
• Then mostly sunny Sunday.
• highs 68-75 lows 43-45. (seasonal averages high 67 low 43)

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Eugene-Springfield Pollen Count:

Grass………. Moderate (19)

Trees………. Moderate (73)

Last Counted: 5/10/17

Data Courtesy of Oregon Allergy Associates.

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Forecast for Roseburg:

• Mostly cloudy with a slight (20%) chance of showers this evening, just mostly cloudy tonight (under 0.10 in. of rain possible),
• Mostly cloudy and a bit warmer with a slight (20%) chance of showers Monday (under 0.10 in. of rain possible, rain Monday night (0.50 in. of rain possible) and Tuesday AM,  showers and a bit cooler in the afternoon (snow level 3,500 ft.) and evening, mostly cloudy with a (30%) chance of showers late Tuesday night (snow level 3,500 ft.),
• Mostly cloudy with a slight (20%) chance of showers and a bit warmer Wednesday, a slight (20%) chance of showers in the evening, then just partly cloudy late Wednesday night.
• lows 43-46 highs 64-55 warming to 62 Wednesday.
• Partly cloudy Thursday AM, sunny and a bit warmer Thursday afternoon, mostly clear at night,
• Mostly sunny Friday, mostly clear Friday night,
• Then mostly sunny and a bit warmer Saturday and Sunday (a bit cooler), mostly clear Saturday night.
• highs 64-76 lows 43-46. (seasonal averages high 70 low 47)

 

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

• Partly cloudy this evening  at the shore and mostly cloudy with a slight (20%) chance of coastal showers late tonight while mostly cloudy inland tonight (under 0.10 in. of rain possible),
• Mostly cloudy with a slight (20%) chance of showers Monday (0.10 in. of rain possible), showers likely (70%) and a bit cooler Tuesday afternoon, a (30%) chance of showers Tuesday night,
• Mostly cloudy with  a (30%) chance of AM showers, partly cloudy with a slight (20%) chance of showers Wednesday AM, just mostly cloudy and a bit warmer Wednesday afternoon, then partly cloudy  Wednesday night.
• lows 45-50 cooling back to 45 Tuesday night and Wednesday night highs 57-54 cooling back to 57 Wednesday.
• Partly cloudy and a bit warmer Thursday, mostly clear at night,
• Then mostly sunny and a bit warmer, mostly clear Friday night,
• Sunny and a bit cooler Saturday, mostly clear at night,
• Then sunny and a bit warmer Sunday.
• highs 63-65 cooling to 60 Saturday warming to 66 Sunday lows 48-50. (seasonal averages high 59 low 47)

 

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Forecast for the Cascades in Lane County:

• Mostly cloudy with a (40%) chance of evening rain and snow showers, a slight (20%) chance of rain and snow showers late tonight (under 0.10 in. of rain possible),
• A mix of clouds and sun with a good (50%) chance of rain and snow showers and a bit cooler Monday afternoon, rain and snow late at night (0.75 in. of rain possible),
• Mostly cloudy with AM rain and snow, rain and snow showers with a slight (20%) chance of thunderstorms and a bit cooler Tuesday afternoon and evening, rain and snow showers likely (70%) late at night,
• Mostly cloudy with a (40%) chance of rain and snow showers and a bit warmer Wednesday, a slight (20%) chance of evening rain and snow showers, then just partly cloudy Wednesday night.
• snow level 4,500 ft. tonight, 5,500 ft. Monday and Monday night, 4,500 ft. Tuesday, 3,500 ft. Tuesday night, 4,000 ft. rising to 5,500 ft. Wednesday afternoon, then 5,500 ft. Wednesday night.
• lows 30-32 cooling to 25 Wednesday night highs 46-38 warming to 42 Wednesday.
• Partly cloudy and a bit warmer Thursday and Thursday night,
• Mostly sunny and a bit warmer Friday, partly cloudy Friday night and Saturday AM, mostly sunny and a bit warmer Saturday afternoon, mostly clear at night,
• Then mostly sunny and a bit warmer Sunday.
• free air freezing level 7,000 ft. rising to 9,000 ft. Thursday, 9,000 ft. Thursday night, 9,000 ft. rising to 10,000 ft. Friday, 10,000 ft. rising to 11,000 ft. Friday night, then 11,000 ft. Saturday through Sunday.
• highs 53-65 lows 30-36.

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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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