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 Low Pressure Trough (“U” shape) is approaching the Pacific Northwest. The graphics for days 1-3 show the frontal system that moved in today. The graphics for days 3-7 show an increase in complex frontal systems moving our way Wednesday through next Sunday continuing 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 25 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 23 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:

• Mostly cloudy with rain tonight (0,25 in. of rain possible),
• Mostly cloudy and a bit cooler with showers Monday (0.25 in. of rain possible), partly cloudy with a slight (20%) chance of evening showers (under 0.10 in. of rain possible), partly cloudy with areas of frost late Monday night,
• Partly cloudy with areas of AM frost, sunny and a bit warmer Tuesday afternoon, partly cloudy at night,
• A mix of clouds and sun with a slight (20%) of showers and a bit warmer Wednesday afternoon, then mostly cloudy with a good (50%) chance of rain Wednesday night.
• lows 42-32 warming to 40 Wednesday night highs 48-57.
• Mostly cloudy with a good (50%) chance of AM rain, rain and a bit cooler Thursday afternoon, rain Thursday night with snow late Thursday night (snow level 1,500 ft.),
• Mostly cloudy with AM showers and snow showers, showers and a bit cooler Friday afternoon (snow level 1,500 ft.), evening showers, a good (50%) chance of rain and snow showers late Friday night (snow level 1,000 ft.),
• Mostly cloudy with AM snow showers and showers likely (70%), a bit warmer with showers likely (70%) Saturday afternoon (snow level 1,500 ft.), a good (50%) chance of evening showers, partly cloudy with a good (50%) chance of showers late Saturday night,
• Mostly cloudy with a good (50%) chance of AM rain and snow showers, then showers likely (70%) and a bit warmer Sunday afternoon.
• highs 49-47 warming to 50 Sunday lows 35-32. (seasonal averages high 57 low 38)

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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 (LRAPA

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Eugene-Springfield Pollen Count:

Forecast for the Umpqua Valley including Roseburg:

• Mostly cloudy with showers and cooler tonight (0.10 in. of rain possible, snow level 2,500 ft.),
• Mostly cloudy with AM rain and snow showers, a bit cooler with scattered rain and snow showers Monday afternoon (under 0.10 in. of rain possible, 1 in. of snow possible), a slight (20%) chance of evening rain and snow showers, just partly cloudy late Monday night,
• Mostly cloudy start, partly cloudy and a bit warmer Tuesday afternoon and evening, mostly cloudy late at night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow, a (30%) chance of rain Wednesday afternoon and evening, then a (30%) chance of rain and snow late Wednesday night.
• lows 42-33 warming to back to 42 Wednesday night highs 52-57.
• Mostly cloudy with a good (50%) chance of AM rain and snow, rain and a bit cooler Thursday afternoon, rain and snow Thursday night,
• Mostly cloudy and a bit cooler with rain and snow Friday, evening rain and snow, a good (50%) chance of rain and snow late at night,
• Mostly cloudy and a bit warmer with rain and snow likely (70%) Saturday, a good (50%) chance of rain and snow Saturday night,
• Mostly cloudy with a good (50%) chance of AM rain and snow, then rain and snow likely (70%) and a bit warmer Sunday afternoon.
• highs 52-47 warming back to 52 Sunday lows 37-33. (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 showers tonight (0.25 in. of rain possible),
• Mostly cloudy with AM showers, a bit cooler with scattered showers Monday afternoon (0.25 in. of rain possible), partly cloudy with patchy coastal frost late Monday night while inland areas of frost late Monday night,
• Partly cloudy and a bit warmer Tuesday and in the evening, mostly cloudy late at night,
• Mostly cloudy with a (30%) chance of rain Wednesday and Wednesday night.
• lows 39-33 warming to 38 Tuesday night and Wednesday night highs 49-54.
• Mostly cloudy with a good (50%) chance of AM rain, rain and a bit cooler Thursday afternoon, evening rain and snow, rain and snow late Thursday night,
• Mostly cloudy with rain and snow and a bit cooler Friday, evening rain and snow, rain and snow likely (70%) at night,
• Mostly cloudy with AM rain and snow likely (70%), rain likely (70%) and a bit warmer Saturday afternoon, a good (50%) chance of evening rain, a (50%) chance of rain and snow late Saturday night,
• Mostly cloudy with a good (50%) chance of AM rain and snow, then rain likely (70%) and a bit warmer Sunday afternoon.
• highs 49-47 warming to 50 Sunday lows 35-33. (seasonal averages high 55 low 42)

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

• Mostly cloudy with rain and snow this evening, rain and snow showers late tonight (0.50 in. of rain possible, 3-7 in. of snow possible),
• Mostly cloudy a bit cooler with snow showers Monday (2-5 in. of snow possible), a good (50%) chance of evening snow showers, just partly cloudy Monday night (1 in. of snow possible),
• Partly cloudy and a bit warmer with a slight (20%) chance of rain and snow showers Tuesday afternoon, a slight (20%) chance of evening showers and snow showers,  a slight (20%) chance of snow showers late Tuesday night,
• Clouds and sun with a slight (20%) chance of AM snow showers, a mix of clouds and sun with a good (50%) chance of rain and snow showers and a bit warmer Wednesday afternoon, then rain and snow likely (70%) Wednesday night.
• snow level 5,000 ft. falling to 4,000 ft. late tonight, 2,500 ft. Monday, 1,500 ft. Monday night, 3,500 ft. Tuesday afternoon, 3,000 ft. Tuesday night, then 3,500 ft. Wednesday and Wednesday night.
• lows 26-19 warming to 26 Wednesday night highs 32-39.
• Mostly cloudy with AM snow likely (70%), snow and rain and a bit cooler Thursday afternoon, snow, possibly heavy at times, Thursday night,
• Mostly cloudy and a bit cooler with snow showers Friday, afternoon snow possibly heavy at times, snow showers at night,
• Mostly cloudy and a bit warmer with snow showers likely (70%) Saturday, a good (50%) chance of evening snow showers, partly cloudy with a good (50%) chance of snow showers Saturday night,
• Mostly cloudy with a good (50%) chance of AM snow showers, then snow showers likely (70%) and a bit warmer Sunday afternoon.
• snow level 3,000 ft. Thursday, 2,000 ft. Thursday night, at the surface Friday through Saturday, 1,500 ft. Saturday night, then 2,000 ft. Sunday.
• highs 34-28 warming to 33 Sunday lows 22-18.

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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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