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 is 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  pushed through the Pacific Northwest from the northeast overnight bringing colder air with it.

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Air Quality Index:

Eugene/Springfield: The Air Quality Index is 12 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 20 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 13 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 4 AM UNTIL 9 AM TODAY FOR THE SOUTH CENTRAL OREGON COAST.
• A FREEZE WATCH IS IN EFFECT FROM THIS EVENING THROUGH MONDAY MORNING FOR THE SOUTH CENTRAL OREGON COAST AND THE CURRY COUNTY COAST.
• A WINTER WEATHER ADVISORY IS IN EFFECT UNTIL 4 AM TODAY FOR CENTRAL OREGON.
• A WIND CHILL ADVISORY IS IN EFFECT UNTIL 11 AM MONDAY FOR THE NORTHERN OREGON CASCADES.
• A WIND CHILL ADVISORY IS IN EFFECT FROM MIDNIGHT TONIGHT UNTIL 11 AM MONDAY FOR THE CASCADES IN LANE COUNTY.
• A WIND CHILL ADVISORY IS IN EFFECT FROM 5 PM TODAY UNTIL 9 AM MONDAY FOR THE SOUTH CENTRAL OREGON CASCADES, THE SISKIYOU MOUNTAINS, THE SOUTHERN OREGON CASCADES, THE KLAMATH BASIN, NORTHERN AND EASTERN KLAMATH COUNTY, AND WESTERN, CENTRAL, AND EASTERN LAKE COUNTY.

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

• Sunny and colder today, clear and cooler tonight,
• Mostly sunny and a bit warmer Monday, partly cloudy in the evening, mostly cloudy late at night,
• Mostly cloudy and a bit warmer Tuesday, then mostly cloudy Tuesday night.
• highs 37-45 low 19-28.
• Mostly cloudy with a slight (20%) chance of rain and a bit warmer Wednesday, a slight (20%) chance of rain and snow Wednesday night,
• Cloudy with a good (50%) chance of rain Thursday, and in the evening, rain likely (70%) late at night,
• Mostly cloudy and a bit warmer with rain likely (70%) Friday, a good (50%) chance of evening rain, a slight (20%) chance of rain late Friday night,
• Then cloudy and a bit warmer with a good (50%) chance of rain Saturday.
• highs 48-50 lows 30-35. (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:

• Sunny and cooler today, clear tonight,
• Sunny and a bit warmer Monday, mostly clear in the evening, mostly cloudy late at night,
• Mostly cloudy and a bit warmer Tuesday, then mostly cloudy Tuesday night,
• highs 40-48 lows 19-30.
• Mostly cloudy with a slight (20%) chance of rain and a bit warmer Wednesday afternoon and evening, a slight (20%) chance of rain and snow late Wednesday night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow, a (30%) chance of rain Thursday afternoon, evening rain likely (70%), rain and snow likely (70%) late at night,
• Mostly cloudy with AM rain likely (70%), a good (50%) chance of rain Friday afternoon, a (30%) chance of rain Friday night,
• Then mostly cloudy with a (30%) chance of rain Saturday.
• highs near 52 lows 33-40 cooling to 37 Friday night. (seasonal averages high 51 low 37)

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

• Widespread AM coastal frost, sunny and a bit cooler today, clear with widespread coastal frost tonight,
• Widespread AM coastal frost, sunny and a bit warmer Monday, mostly clear in the evening, mostly cloudy late at night,
• Mostly cloudy and a bit warmer Tuesday, then mostly cloudy Tuesday night.
• highs 42-49 lows 22-32.
• Mostly cloudy with a slight (20%) chance of rain and a bit warmer Wednesday, a slight (20%) chance of rain Wednesday night,
• Mostly cloudy with a (30%) chance of AM rain, rain likely (70%) and a bit warmer Thursday and at night,
• Mostly cloudy with rain likely (70%) Friday, a (30%) chance of rain of rain Friday night,
• Then mostly cloudy with a (40%) chance of rain Saturday.
• highs 52-55 lows 35-39. (seasonal averages high 54 low 41)

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Forecast for the Cascades in Lane County:

• Mostly sunny and cooler today (-15 wind chill temperature possible in AM) and blustery (Wind: E 15-25 mph gusts to 40 mph), clear and cold tonight (-15 wind chill temperature possible),
• Sunny and warmer Monday (-10 wind chill temperature possible in AM), partly cloudy in the evening, mostly cloudy Monday night,
• A mix of clouds and sun and a bit warmer Tuesday, then mostly cloudy Tuesday night.
• free air freezing level at the surface today through Monday, 4,000 ft. rising to 4,500 ft. Monday night, then 6,000 ft. Tuesday and Tuesday night.
• highs 16-39 lows 4-23.
• A mix of clouds and sun and a bit warmer Wednesday, mostly cloudy with a slight (20%) chance of rain and snow late Wednesday night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow, a bit cooler Thursday with a good (50%) chance of rain and snow Thursday night,
• Mostly cloudy and a bit cooler with a snow and rain likely (70%) Friday, a (40%) chance of evening rain and snow, a slight (20%) chance of rain and snow late Friday night,
• Then mostly cloudy and a bit warmer with a (40%) chance of rain and snow Saturday.
• snow level 7,500 ft. Wednesday through Friday, then 4,500 ft. Friday night and Saturday.
• highs 42-36 warming to 39 Saturday lows 24-28 cooling back to 24 Friday night.

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