Here is my weekly weather quiz question for the last time. What is“Isentropic Analysis?  Here is the correct answer. Isentropic Analysis is a way the forecaster can look at the atmosphere in 3-dimensions instead of looking at constant pressure surfaces (such as the 850 mb, 700 mb, 500 mb, etc.) which are in 2-dimensions. In this analysis method, the forecaster looks at constant potential temperature (the temperature that it would take if we compressed or expanded it adiabatically to the pressure of 1000 mb) surfaces. Air parcels move up and down these surfaces; therefore, the forecaster can see where the moisture is located and how much moisture is available.

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An Upper Level High Pressure Ridge (“Arch” shape) is moving over the Pacific Northwest giving us one more dry with warmer day. The graphics for days 1-3 show the frontal system approaching the coast Sunday. The graphics for days 3-7 show an increase in complex frontal systems moving our way Tuesday through next Saturday bringing back the rain chances.

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Air Quality Index:

Eugene/Springfield: The Air Quality Index is 38 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 39 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 48 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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ADVISORIES:

• NONE AT THIS TIME.

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

• Some AM clouds, mostly cloudy, possible sun breaks, and a bit warmer this afternoon, a slight (20%) chance of rain tonight,
• Mostly cloudy with rain and cooler Sunday (0.10 in. of rain possible), showers Sunday night (0,25 in. of rain possible),
• Mostly cloudy and a bit cooler with showers likely (70%) Monday, a good (50%) chance of evening showers, a slight (20%) chance of showers late Monday night.
• highs 64-50 lows 43-33.
• Clouds and sun with a slight (20%) chance of AM showers, a mix of clouds and sun and a bit warmer with a (40%) chance of showers Tuesday afternoon, partly cloudy with a good (50%) chance of evening showers, mostly cloudy with a good (50%) chance of showers late Tuesday night,
• Mostly cloudy with a good (50%) chance of AM showers, showers likely (70%) and a bit cooler Wednesday afternoon, a good (50%) chance of showers at night,
• Mostly cloudy with a good (50%) chance of AM showers, showers likely (70%) and a bit cooler Thursday afternoon, showers Thursday night,
• Then mostly cloudy and a bit cooler with showers Friday.
• highs 53-46 lows 33-37 cooling to 34 Thursday night. (seasonal averages high 57 low 37)

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Home Wood Heating Advisory:

Posted Daily

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 (LRAPAz

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Forecast for the Umpqua Valley including Roseburg:

• Mostly cloudy and a bit warmer today, a (30%) chance of rain late tonight (under 0.10 in. of rain possible),
• Mostly cloudy with AM rain likely (70%), rain and a bit cooler Sunday afternoon (0.10 in. of rain possible), evening rain likely (70%), a good (50%) chance of rain and cooler Sunday night (0.10 in. of rain possible),,
• Mostly cloudy and cooler with rain and snow likely (70%) Monday, then a good (50%) chance of rain and snow Monday night.
• highs 64-50 lows 45-35.
• Mostly cloudy with a slight (20%) chance of AM rain and snow, a bit warmer with a slight (20%) chance of rain Tuesday afternoon, a slight (20%) chance of rain and snow Tuesday night,
• Mostly cloudy and a bit cooler with a (40%) chance of rain and snow Wednesday and at night,
• Mostly cloudy with a good (50%) chance of AM rain and snow, rain and snow likely (70%) and a bit cooler Thursday afternoon and evening,  a good (50%) chance of rain and snow late Thursday night,
• Mostly cloudy with a good  (50%) chance of AM rain and snow, then rain and snow likely (70%) Friday afternoon.
• highs 53-49 lows 38-36. (seasonal averages high 59 low 40)

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

• Mostly cloudy with patchy AM inland fog, mostly cloudy and a bit warmer this afternoon, cloudy with a (40%) chance of rain late tonight (0.10 in. of rain possible),
• Mostly cloudy and a bit cooler with rain Sunday (0.25 in. of rain possible), a good (50%) chance of coastal rain at night while evening inland rain likely (70%), a good (50%) chance of inland rain late Sunday night (0.25 in. of rain possible),
• Mostly cloudy and a bit cooler with rain likely (70%) Monday, a good (50%) chance of evening rain, then a slight (20%) chance of rain and snow late Monday night.
• highs 57-50 lows 42-33.
• Mostly cloudy with a slight (20%) chance of AM rain and snow, partly cloudy and a bit warmer with a slight (20%) chance of rain Tuesday afternoon, a (30%) of rain Tuesday night,
• Mostly cloudy and a bit cooler with a (40%) chance of rain Wednesday, a (30%) chance of rain at night,
• Mostly cloudy with a good (50%) chance of AM rain, mostly cloudy and a bit cooler with rain likely (70%) Thursday afternoon and evening, a good (50%) chance of rain and snow late Thursday night,
• Mostly cloudy with AM rain and snow likely (70%), then rain likely (70%) and a bit cooler Friday afternoon.
• highs 54-48 lows near 35. (seasonal averages high 55 low 42)

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Forecast for the Northern Oregon Cascades including the Cascades in Lane County:

• Mostly sunny start, A mix of clouds and sun and a bit warmer this afternoon, mostly cloudy with a slight (20%) chance of rain tonight and a (30%) chance of snow late tonight (under 0.10 in. of rain possible),
• Mostly cloudy with AM rain and snow, rain and a bit cooler Sunday afternoon, rain and snow showers Sunday night (no snow accumulation expected),
• Mostly cloudy a bit cooler with rain showers and snow showers Monday, a good (50%) chance of evening showers, and good (50%) chance of snow showers late at night.
• free air freezing level 6,500 ft. rising to 7,500 ft. this afternoon, snow level 5,000 ft. tonight and Sunday, 4,000 ft. Sunday night, 3,000 ft. Monday, then 2,500 ft. Monday night.
• highs 46-34 lows 32-19.
• A mix of clouds and sun and a bit warmer with a good (50%) chance of snow showers Tuesday with a good (50%) chance of rain and snow showers in the afternoon, a good (50%) chance of evening showers and snow showers, a good (50%) chance of snow showers late Tuesday night,
• Mostly cloudy with a good (50%) chance of AM snow showers, snow showers with rain showers likely (70%) and a bit cooler Wednesday afternoon, evening snow and rain showers likely (70%), a good (50%) chance of snow showers late at night,
• Mostly cloudy with a good (50%) chance of AM snow showers, snow and rain showers likely (70%) Thursday afternoon, evening snow and rain showers, snow showers likely (70%) late Thursday night,
• Then mostly cloudy and a bit cooler with snow showers Friday.
• snow level 2,500 ft. Tuesday, 3,000 ft. Tuesday night, 2,500 ft, Wednesday through Thursday night, then 2,000 ft. Friday.
• highs 36-30 lows 23-20.

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For all of your Eugene-Springfield and Lane County News, Weather, and Sports go to: EugeneDailyNews.com

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