Here is my new weekly weather quiz question. What is the “dew point?”  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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An upper level high pressure ridge that gave us record high temperatures in the 100s will slowly move away allowing an upper low pressure trough to bring an increased southerly airflow. That means more clouds and the slight chance of showers and thunderstorms with a cooling trend to more reasonable temperatures.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 25 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 26 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 30 in the Good category measuring Particulate Matter.

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

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Advisories:

• A RED FLAG WARNING IS IN EFFECT FROM 2 PM UNTIL  11 PM TODAY THE UMPQUA NATIONAL FOREST,  THE SOUTHERN OREGON CASCADES, THE KLAMATH BASIN AND THE FREMONT-WINEMA NATIONAL FOREST.
• A RED FLAG WARNING IS IN EFFECT FROM 2 PM UNTIL 11 PM TODAY FOR THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN IN EASTERN LAKE AND WESTERN HARNEY COUNTIES.
• A RED FLAG WARNING IS IN EFFECT UNTIL 11 PM TONIGHT FOR THE SOUTH CENTRAL OREGON COAST, THE UMPQUA BASIN, THE WESTERN ROGUE RIVER INCLUDING THE ILLINOIS VALLEY AND THE EASTERN ROGUE RIVER VALLEY.
• A HEALTH ADVISORY HAS BEEN ISSUED FOR UPPER KLAMATH LAKE AND AGENCY LAKE DOWN TO KENO DAM, LOCATED JUST NORTH OF KLAMATH FALLS ALONG HIGHWAY 97 IN KLAMATH COUNTY. WATER MONITORING BY THE USGS HAS CONFIRMED THE PRESENCE OF BLUE-GREEN ALGAE TOXINS WHICH CAN BE HARMFUL TO HUMANS AND ANIMALS. SWALLOWING, INHALING OR SKIN CONTACT WITH WATER DROPLETS SHOULD BE AVOIDED.

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

• Mostly cloudy with a slight (20%) chance of showers and thunderstorms this AM, partly cloudy and warmer this afternoon, partly cloudy tonight and Tuesday AM, mostly sunny in the afternoon, mostly clear Tuesday night,
• Mostly sunny Wednesday, then partly cloudy Wednesday night.
• highs 88-83 lows 56-53.
• Mostly sunny Thursday, partly cloudy Thursday night through Saturday evening, mostly cloudy late Saturday night,
• Then a mix of clouds and sun Sunday.
• highs 83-85 cooling to near 80 Sunday lows near 55. (seasonal averages high 84 low 52)
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  Eugene/Springfield Pollen Count:

Trees: Low- 4

Grass: Moderate- 5*

Reading as of: 7/25/15

*Now the grass pollen season is officially over.

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Forecast for the Umpqua Basin including Roseburg:

• Mostly cloudy with areas of smoke and a slight (20%) chance of isolated thunderstorms this afternoon and evening (under 0.10 in. of rain possible, more in storms), mostly clear with areas of smoke late tonight,
• Sunny with areas of sun in the AM, partly cloudy Tuesday afternoon, mostly clear Tuesday night,
• Sunny and cooler Wednesday, then mostly clear Wednesday night.
• highs 90-86 lows 59-57.
• Partly cloudy and a bit warmer Thursday, partly cloudy Thursday night through Saturday night,
• Then mostly cloudy Sunday with a slight (20%) chance of thunderstorms in the afternoon.
• highs 92-86 lows 58-60. (seasonal averages high 86 low 57)

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

• Mostly cloudy this AM with patchy coastal fog, partly cloudy with patchy coastal fog tonight,
• Partly cloudy with patchy coastal AM fog, sunny Tuesday afternoon, mostly clear at night,
• Then partly cloudy Wednesday AM, sunny in the afternoon, then mostly clear Wednesday night.
• highs near 66 lows 57-55.
• Partly cloudy Thursday through Saturday, then mostly cloudy Saturday night and Sunday.
• highs 67-70 cooling to 65 Sunday lows near 56. (seasonal averages high 65 low 53)

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Forecast for the Cascades in Lane County:

• Mostly cloudy with a slight (20%) chance of AM showers and thunderstorms, partly cloudy with a slight (20%) chance of showers and thunderstorms this afternoon and evening, just partly cloudy late tonight,
• Mostly sunny Tuesday AM, partly cloudy and cooler in the afternoon, mostly clear Tuesday night,
• Mostly sunny Wednesday, then partly cloudy Wednesday night.
• snow level above 8,000 ft. today and tonight, free air freezing level 13,000 ft. Tuesday through Wednesday night.
• highs 77-72 lows 50-46.
• Mostly sunny Thursday, partly cloudy Thursday night,
• Partly cloudy Friday with a slight (20%) chance of showers and thunderstorms in the afternoon through Saturday evening, mostly cloudy with a slight (20%) chance of showers late Saturday night,
• A mix of clouds and sun with a slight (20%) chance of showers Sunday AM, then a slight (20%) chance of showers and thunderstorms and a bit warmer in the afternoon.
• free air freezing level 14,000 ft. Thursday, 13,000 ft. Thursday night, then snow level above 8,000 ft. Friday through Sunday.
• highs 72-66 warming to 68 Sunday lows near 49.

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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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