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.

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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 18 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 8 PM TUESDAY 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:

• Mostly clear this evening, partly cloudy late tonight,
• AM clouds, mostly sunny and a bit cooler Tuesday afternoon, mostly clear in the evening, mostly cloudy late Tuesday night and Wednesday AM, mostly sunny and cooler in the afternoon, partly cloudy in the evening, mostly cloudy Wednesday night and Thursday AM, mostly sunny and a bit warmer in the afternoon, then partly cloudy Thursday night.
• lows 57-54 highs 82-78 warming back to 82 Thursday.
• Partly cloudy Friday through Saturday night,
• A mix of clouds and sun Sunday AM, mostly sunny and a bit cooler in the afternoon, partly cloudy Sunday night and Monday AM, then mostly sunny Monday afternoon.
• highs 86-82 lows 54-57 cooling back to 54 Sunday night. (seasonal averages high 84 low 52)

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Forecast for the Umpqua Basin including Roseburg:

• Mostly clear tonight,
• Mostly cloudy in the AM, partly cloudy and cooler Tuesday afternoon, mostly clear in the evening, partly cloudy late at night,
• Mostly cloudy in the AM, sunny and a bit cooler Wednesday afternoon, partly cloudy in the evening, mostly cloudy late Wednesday night,
• Mostly cloudy in the AM, sunny and a bit warmer Thursday afternoon, then mostly clear Thursday night.
• lows 60-55 highs 84-80 warming to 83 Thursday.
• Mostly sunny and a bit warmer Friday and Saturday, mostly clear Friday night, partly cloudy Saturday night,
• Partly cloudy and a bit cooler Sunday, mostly clear in the evening, partly cloudy late Sunday night and Monday AM, then sunny and a bit warmer Monday afternoon.
• highs 89-85 warming to 88 Monday 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:

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

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Forecast for the Cascades in Lane County:

• Clear tonight,
• Mostly sunny Tuesday, partly cloudy and cooler Tuesday night through Wednesday night,
• A mix of clouds and sun Thursday AM, mostly sunny in the afternoon, then partly cloudy Thursday night.
• free air freezing level 14,000 ft. tonight, 14,000 ft. falling to 13,000 ft. Tuesday, 13,000 ft. Tuesday night, then 12,000 ft. Wednesday and Wednesday night, 11,000 ft. Thursday, then 12,000 ft. Thursday night.
• lows 47-43 highs 72-66.
• Partly cloudy Friday AM, mostly sunny and a bit warmer in the afternoon, partly cloudy Friday night,
• Mostly sunny Saturday AM, partly cloudy Saturday afternoon through Monday AM, then mostly sunny Monday afternoon.
• free air freezing level 13,000 ft. Friday through Sunday night, then 12,000 ft. Monday.
• highs 72-69 lows 47-45.

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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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