Here is my weekly weather quiz question for the last time. What is “Instability“? Here is the correct answer. Instability (abbrev. INSTBY)- is the tendency for air parcels to accelerate when they are displaced from their original position; especially, the tendency to accelerate upward after being lifted. Instability is a prerequisite for severe weather – the greater the instability, the greater the potential for severe thunderstorms.

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A very strong Jet Stream flow www.wunderground.com/maps/wind/jet-stream  from the northeast will be sending much cooler air to the Pacific Northwest. A weak frontal system moved in Friday but a stronger cold front www.wpc.ncep.noaa.gov will push through the Pacific Northwest from the northeast today and tonight bringing colder air with it.

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Air Quality Index:

Eugene/Springfield: The Air Quality Index is 15 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 32 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 14 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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ADVISORIES:

• A FREEZE WATCH IS IN EFFECT FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR THE SOUTH CENTRAL OREGON COAST.
• A FREEZE WATCH IS IN EFFECT FROM SUNDAY EVENING THROUGH MONDAY MORNING FOR THE SOUTH CENTRAL OREGON COAST.

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

• Mostly cloudy with a slight (20%) chance of AM rain, a bit cooler with rain likely (70%) this afternoon and evening (under 0.10 in. of rain possible), partly cloudy with a slight (20%) chance of snow late tonight (under 0.10 in. of rain possible),
• Sunny and a bit cooler Sunday, clear Sunday night,
• AM clouds and sun, sunny and a bit warmer Monday afternoon, partly cloudy in the evening, then mostly cloudy at night.
• highs 44-37 warming to 38 Monday low 25-19 warming to 23 Monday night.
• Mostly cloudy and a bit warmer Tuesday, a slight (20%) chance of rain late Tuesday night (snow level 500 ft.),
• Mostly cloudy with a slight (20%) chance of AM snow, mostly cloudy with a slight (20%) chance of rain and a bit warmer Wednesday (snow level 500 ft.), a slight (20%) chance of rain at night,
• Cloudy with a (40%) chance of rain and a bit warmer Thursday, mostly cloudy with a good (50%) chance of rain Thursday night ,
• Then cloudy with a good (50%) chance of rain Friday.
• highs 43-48 lows 27-34. (seasonal averages high 49 low 35)

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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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Forecast for the Umpqua Valley including Roseburg:

• Mostly cloudy and a bit cooler with a (30%) chance of rain today, a (30%) chance of rain and snow tonight (under 0.10 in. of rain possible, snow level 2,000 ft. falling to 100 ft. late at night),
• Sunny and a bit cooler Sunday, clear Sunday night,
• Sunny and a bit warmer Monday, mostly clear in the evening, then mostly cloudy late Monday night.
• highs 46-39 warming to 43 Monday lows 30-19 warming to 25 Monday night.
• Partly cloudy and a bit warmer Tuesday and Tuesday night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow showers, a bit warmer with a slight (20%) chance of showers Wednesday afternoon, a slight (20%) chance of rain and snow at night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow, a (30%) chance of rain Thursday afternoon, a (40%) chance of rain Thursday night,
• Then mostly cloudy with a (40%) chance of rain Friday.
• highs 48-52 lows 30-36. (seasonal averages high 51 low 37)

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

• Mostly cloudy with a slight (20%) chance of AM coastal rain with coastal rain likely (70%) this afternoon while a (30%) chance of inland rain today (under 0.10 in. of rain possible), a (40%) chance of coastal rain tonight while a good (50%) chance of inland evening rain and a good (50%) chance of inland rain and snow late tonight (0.10 in. of rain possible),,
• Sunny and a bit cooler Sunday, clear Sunday night,
• Sunny and a bit warmer Monday, mostly clear in the evening, then mostly cloudy Monday night.
• highs 49-43 warming to 46 Monday lows 30-23 warming to 28 Monday night.
• Mostly cloudy and a bit warmer Tuesday, a slight (20%) chance of showers late Tuesday night,
• Mostly cloudy with a slight (20%) chance of showers and a bit warmer Wednesday, mostly cloudy with a slight (20%) chance of rain at night,
• Mostly cloudy with a (30%) chance of rain and a bit warmer Thursday, a good (50%) chance of rain Thursday night,
• Then mostly cloudy and a bit cooler with a (40%) chance of rain Friday.
• highs 52-54 cooling back to 52 Friday lows 32-38. (seasonal averages high 54 low 41)

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Forecast for the Cascades in Lane County:

• Mostly cloudy with a good (50%) chance of AM snow, snow and a bit cooler this afternoon (1 in. of snow possible), evening snow, a slight (20%) chance of snow and colder late tonight,
• Mostly sunny and cooler Sunday, clear Sunday night,
• Mostly sunny and warmer Monday, mostly clear in the evening, then mostly cloudy Monday night.
• snow level 2,500 ft. today, at the surface tonight, free air freezing level at the surface Sunday through Monday night.
• highs 29-18 warming to 30 Monday lows 10-4 warming to 14 Monday night.
• Mostly cloudy and a bit warmer Tuesday, mostly cloudy Tuesday night,
• A mix of clouds and sun and a bit warmer with a slight (20%) chance  of snow Wednesday and a slight (20%) chance of afternoon rain, a slight (20%) chance of rain and snow at night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow, a bit cooler Thursday, a (40%) chance of rain and snow Thursday night,
• Then mostly cloudy and a bit cooler with a (40%) chance of rain and snow Friday.
• free air freezing level at the surface Tuesday, 4,000 ft. Tuesday night, snow level 3,000 ft. Wednesday, then 4,000 ft. Wednesday night through Friday.
• highs 36-42 cooling to 38 Friday lows 20-25.

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