Here is my new weekly weather quiz question. What is “Zonal Flow ?”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 low Shaded “U” shape with blue arrows) will be replacing the high pressure ridge (Shaded “Arch” shape with blue arrows). That means an increased onshore flow that will cool us down considerably. Then we’ll start to warm up again by Thursday. It looks like rather pleasant weather for the Lane County Fair that begins Wednesay and continues through Sunday.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 24 in the Good category measuring Ozone.

Oakridge: The Air Quality Index is 15 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 25 in the Good category measuring Ozone.

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

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Advisories:

• A RED FLAG WARNING IS IN EFFECT UNTIL 11 PM TONIGHT FOR ABUNDANT LIGHTNING AND DRY FUELS FOR THE KLAMATH BASIN, THE FREMONT WINEMA NATIONAL FOREST AND THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE AND HARNEY COUNTIES.
• A RED FLAG WARNING IS IN EFFECT UNTIL 8 PM TODAY FOR WINDY CONDITIONS AND LOW RELATIVE HUMIDITY FOR THE EAST SLOPES OF THE NORTHERN OREGON CASCADES AND THE LOWER COLUMBIA BASIN OF OREGON.

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

• Partly cloudy tonight,
• Mostly cloudy Wednesday AM, mostly sunny and a bit cooler in the afternoon, partly cloudy in the evening, mostly cloudy late Wednesday night and Thursday AM, mostly sunny and a bit warmer in the afternoon, partly cloudy Thursday night,
• Mostly sunny in the AM, then partly cloudy Friday afternoon and at night.
  lows 54-58 highs 80-86.
• Partly cloudy Saturday and in the evening, mostly cloudy late Saturday night,
• Partly cloudy Sunday through Monday AM, then mostly sunny and warmer Monday afternoon and Tuesday, mostly clear Monday night.
• highs 86-82 warming back to 86 Tuesday lows 58-54. (seasonal averages high 84 low 52)

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Forecast for the Umpqua Basin including Roseburg:

• Mostly clear this evening, partly cloudy late tonight,
• Mostly cloudy in the AM, sunny and a bit cooler Wednesday afternoon, partly cloudy in the evening, mostly cloudy late Wednesday night and Thursday AM, sunny and a bit warmer Thursday afternoon, mostly clear Thursday night,
• Mostly sunny and a bit warmer Friday, then mostly clear Friday night.
• lows 58-55 warming back to 58 Friday night highs 83-89.
• Mostly sunny and a bit cooler Saturday, partly cloudy Saturday night and Sunday, mostly clear in the evening, partly cloudy late Sunday night,
•  Mostly sunny and warmer Monday and Tuesday, mostly clear Monday night.
• highs 87-84 warming to 92 Tuesday lows near 60. (seasonal averages high 86 low 57)

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

• Partly cloudy this evening, mostly cloudy late tonight and Wednesday AM, sunny in the afternoon, mostly cloudy Wednesday night,
• Mostly cloudy Thursday AM, sunny in the afternoon, mostly clear with patchy coastal fog late Thursday night,
• Patchy fog Friday AM, then just partly cloudy Friday afternoon and at night.
• lows near 55 highs near 65.
• Partly cloudy Saturday through Monday AM, sunny Monday afternoon, mostly clear at night,
• Then mostly sunny Tuesday.
• highs near 65 lows near 56. (seasonal averages high 65 low 53)

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Forecast for the Cascades in Lane County:

• Partly cloudy and cooler tonight through Wednesday night,
• A mix of clouds and sun Thursday AM, mostly sunny in the afternoon and Friday, partly cloudy Thursday night.
• free air freezing level 13,000 ft. tonight, 12,000 ft. Wednesday and Wednesday night, 11,000 ft. Thursday, 13,000 ft. Thursday night and Friday, then 12,000 ft. Friday.
• lows 43-47 highs 67-72.
• Partly cloudy Saturday through Monday AM, then mostly sunny Monday afternoon and Tuesday, mostly clear Monday night.
• free air freezing level 12,000 ft. Saturday and Saturday night, 11,000 ft. Sunday, 12,000 ft. Sunday night, 11,000 ft. Monday, then 12,000 ft. Monday night and Tuesday.
• highs 72-68 warming to 75 Tuesday lows 47-42 warming to 75 Monday night.

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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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