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 3-7 show a frontal system pushing through the Pacific Northwest Monday night and Tuesday.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 4 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 7 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 1 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:

• Mostly cloudy with showers and a slight (20%) chance of thunderstorms and small hail possible this afternoon (0.25 in. of rain possible, more in storms), evening showers likely (70%) with a slight (20%) chance of thunderstorms, a good (50%) chance of showers late tonight (0.10 in. of rain possible, more in storms),
• Mostly cloudy with a good (50%) chance of AM showers, showers (0.10 in. of rain possible) likely (70%) and a bit warmer Sunday (Mother’s Day), a (40%) chance of evening showers, a slight (20%) chance of showers late at night,
• Cloudy with a good (50%) chance of showers and a bit cooler Monday, evening rain, then showers late Monday night.
• highs 55-59 cooling to 56 Monday lows 42-45.
• Mostly cloudy with showers likely (70%) Tuesday, a good (50%) chance of showers Tuesday night,
• Mostly cloudy and a bit warmer with a slight (20%) chance of afternoon and evening showers,  mostly cloudy late at night,
• Mostly cloudy to start, partly cloudy and a bit warmer Thursday afternoon through Friday AM, then mostly sunny Friday afternoon.
• highs 58-69 lows 43-46. (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 showers this afternoon, cloudy with evening showers likely (70%), a (40%) chance of showers late tonight,
• Mostly cloudy with a (30%) chance of showers and a bit warmer Sunday (Mother’s Day), a slight (20%) chance of showers at night,
• Cloudy and a bit cooler with a (30%) chance of showers Monday (AM snow level 3,500 ft.), rain Monday night.
• highs 53-62 cooling to 58 Monday lows 42-45.
• Mostly cloudy rain and a bit cooler Tuesday, a good (50%) chance of showers at night and Wednesday (a bit warmer), a slight (20%) chance of showers in the evening, just mostly cloudy late Wednesday night,
• Then partly cloudy Thursday through Friday.
• highs 55-73 lows near 44. (seasonal averages high 70 low 47)

 

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

• Mostly cloudy with showers this afternoon (0.25 in. of rain possible), cloudy with evening showers likely (70%), a good (50%) chance of showers late tonight (under 0.10 in. of rain possible),
• Mostly cloudy with a (40%) chance of showers and a bit warmer Sunday (Mother’s Day), a slight (20%) chance of showers Sunday night,
• Mostly cloudy with a good (50%) chance of AM showers, showers likely (70%) and a bit cooler Monday afternoon, then rain at night.
• highs 54-56 lows 45-47.
• Mostly cloudy with AM rain, showers likely (70%) and a bit cooler Tuesday afternoon and in the evening, a good (50%) chance of showers Tuesday night,
• Mostly cloudy with  slight (20%) chance of showers and a bit warmer Wednesday and in  the evening, just mostly cloudy Wednesday night and Thursday AM, then partly cloudy and a bit warmer Thursday afternoon through Friday.
• highs 54-64 lows 45-47. (seasonal averages high 59 low 47)

 

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Forecast for the Cascades in Lane County:

• Mostly cloudy with rain and snow showers this afternoon and evening with possible thunderstorms and small hail (0.25 in. of rain possible, 1-4 in. of snow possible), rain and snow shower chances decreasing to (40%) late tonight,
• Mostly cloudy and a bit warmer with a good (50%) chance of rain and snow showers (0.10 in. of rain possible) Sunday (Mother’s Day), a (40%) chance of rain and snow showers  in the evening, rain and snow shower chances decreasing to a slight (20%) chance of showers late at night,
• Mostly cloudy with a good (50%) chance of showers Monday and a bit cooler, evening rain and snow, then rain and snow showers late Monday night.
• snow level 3,500 ft. today, 4,000 ft. tonight, 3,500 ft. Sunday, 4,500 ft. Sunday night, 4,000 ft. Monday, then 4,500 ft. Monday night.
• highs 39-44 lows 28-30.
• Mostly cloudy with rain and snow showers and a bit cooler Tuesday, cloudy with rain and snow showers in the evening, a good (50%) chance of rain and snow showers late at night,
• A good (50%) chance of rain and snow showers and a bit warmer Wednesday, a (40%) chance of rain and snow showers Wednesday night,
• A mix of clouds and sun and a bit warmer Thursday, then partly cloudy and a bit warmer Thursday night and Friday.
• snow level 3,500 ft. Tuesday and Tuesday night, 4,000 ft. Wednesday, 5,000 ft. Wednesday evening, free air freezing level 7,000 ft. late Wednesday night, 7,000 ft. rising to 9,000 ft. Thursday, 9,000 ft. Thursday night, then 9,000 ft. rising to 10,000 ft. Friday.
• highs 37-56 lows 28-32.

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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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