Here is my weekly weather quiz question. What is “Instability“?

_________________

A very strong Jet Stream flow from the northeast will be sending much cooler air to the Pacific Northwest. A frontal system will push through the Pacific Northwest from the northeast Saturday.

________________

Air Quality Index:

Eugene/Springfield: The Air Quality Index is 55 in the Moderate category measuring Particulate Matter.

Oakridge: The Air Quality Index is 53 in the Moderate category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 25 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

________________

ADVISORIES:

• AN AIR STAGNATION ADVISORY IS IN EFFECT UNTIL 3 PM TODAY FOR THE EASTERN COLUMBIA RIVER GORGE, THE LOWER COLUMBIA BASIN OF OREGON, THE FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON, THE FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON, AND NORTH CENTRAL OREGON.
• A WIND ADVISORY IS IN EFFECT UNTIL 10 AM TODAY FOR THE EASTERN COLUMBIA RIVER GORGE, THE LOWER COLUMBIA BASIN OF OREGON, THE FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON, THE FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON, AND NORTH CENTRAL OREGON.
• A BEACH HAZARDS STATEMENT FOR DANGEROUS SNEAKER WAVES IS IN EFFECT THROUGH THIS AFTERNOON THE SOUTH CENTRAL OREGON COAST AND THE CURRY COUNTY COAST.
• AN AIR STAGNATION ADVISORY IS IN EFFECT UNTIL 11 AM TODAY FOR THE COAST RANGE OF NORTHWEST OREGON, THE CENTRAL COAST RANGE OF WESTERN OREGON, THE CENTRAL WILLAMETTE VALLEY, THE SOUTH WILLAMETTE VALLEY, THE NORTHERN OREGON CASCADE FOOTHILLS, AND THE CASCADE FOOTHILLS OF THE CASCADES IN LANE COUNTY.
• AN AIR STAGNATION ADVISORY IS IN EFFECT UNTIL 3 PM TODAY FOR THE JOHN DAY BASIN AND AND CENTRAL OREGON.
• AN AIR STAGNATION ADVISORY IS IN EFFECT UNTIL NOON TODAY FOR CENTRAL DOUGLAS COUNTY, EASTERN CURRY COUNTY AND JOSEPHINE COUNTY, JACKSON COUNTY, THE KLAMATH BASIN, NORTHERN AND EASTERN KLAMATH COUNTY, AND WESTERN, CENTRAL, AND EASTERN LAKE COUNTY.
• A WINTER WEATHER ADVISORY IS IN EFFECT UNTIL 7 PM FRIDAY FOR THE NORTHERN BLUE MOUNTAINS OF OREGON.

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

• Cloudy with a good (50%) chance of AM rain, a slight (20%) chance of showers and a bit warmer this afternoon, mostly cloudy with a slight (20%) chance of showers tonight (under 0.10 in. of rain possible),
• Mostly cloudy and a bit cooler with showers likely (70%) Saturday (under 0.10 in. of rain possible), a good (50%) chance of evening showers, partly cloudy late at night,
• Sunny and a bit cooler Sunday, then clear Sunday night.
• highs 46-36 low 36-18.
• Mostly sunny and a bit warmer Monday, partly cloudy Monday night,
• A mix of clouds and a bit warmer Tuesday, partly cloudy in the evening, mostly cloudy at night,
• Mostly cloudy with a slight (20%) chance of AM snow showers, a bit warmer with a slight (20%) chance of showers Wednesday afternoon (snow level 500 ft.), a slight (20%) chance of showers Wednesday night,
• Then mostly cloudy with a (40%) chance of showers Thursday.
• highs 37-46 lows 20-27. (seasonal averages high 49 low 35)

__________

Home Wood Heating Advisory:

Posted Daily

Eugene-Springfield: YELLOW– Caution is Advised.

Oakridge: YELLOW– Caution is Advised.

*Note: Pellet stoves may be used anytime if they produce no visible emissions.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

__________

Forecast for the Umpqua Valley including Roseburg:

• Mostly cloudy with areas of AM fog and a (30%) chance of showers, a (30%) chance of of showers and a bit warmer this afternoon (under 0.10 in. of rain possible, snow level 3,500 ft.), a slight (20%) chance of evening showers (snow level 3,000 ft.), a slight (20%) chance of rain and  snow showers late tonight,
• Mostly cloudy with a (30%) chance of rain and snow showers Saturday (under 0.10 in. of rain possible, snow level 2,000 ft. rising to 2,500 ft.), a (40%) chance of rain and snow showers at night (0.10 in. of rain possible, snow level 1,000 ft. falling to 200 ft. late at night),
• Mostly cloudy start, sunny and a bit cooler Sunday afternoon, then clear Sunday night.
• highs 45-38 lows 39-19.
• Sunny and a bit warmer Monday, mostly clear Monday night,
• Partly cloudy and a bit warmer Tuesday and at night,
• Mostly cloudy with a slight (20%) chance of rain and snow showers and a bit warmer Wednesday and Wednesday night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow showers, then a slight (20%) chance of showers and a bit warmer Thursday afternoon.
• highs 39-50 lows 24-33. (seasonal averages high 51 low 37)

___________

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

• Mostly cloudy and a bit cooler with a (30%) chance of showers today, a slight (20%) chance of showers tonight (under 0.10 in. of rain possible),
• Mostly cloudy with a slight (20%) chance of AM coastal showers with coastal showers likely (70%) and a bit cooler Saturday afternoon while a slight (20%) chance of inland showers and a bit cooler in the afternoon (under 0.10 in. of rain possible), evening coastal showers likely (70%) and a good (50%) chance of coastal rain and snow showers late at night while a (40%) chance of inland rain and snow showers at night (0.10 in. of rain possible),
• Sunny and a bit cooler Sunday, then clear Sunday night.
• highs 49-40 lows 39-23.
• Sunny and a bit warmer Monday, mostly clear in the evening, partly cloudy Monday night,
• Partly cloudy and a bit warmer Tuesday and at night,
• Mostly cloudy with a slight (20%) chance of AM rain and snow showers, partly cloudy and a bit warmer with a slight (20%) chance of showers Wednesday afternoon, mostly cloudy with a slight (20%) chance of showers Wednesday night,
• Then mostly cloudy with a (30%) chance of showers Thursday.
• highs 44-52 lows 27-33. (seasonal averages high 54 low 41)

__________

Forecast for the Cascades in Lane County:

• Mostly cloudy with AM rain and snow showers likely (70%), a good (50%) chance of rain and snow showers and a bit warmer this afternoon (0.25 in. of rain possible, 1-3 in. of snow possible), a good (50%) chance of evening showers, a good (50%) chance of snow showers late tonight (under 0.10 in. of rain possible, 1 in. of snow possible),
• Mostly cloudy with a good (50%) chance of AM snow showers, snow showers and a bit cooler Saturday afternoon, evening snow showers, partly cloudy with a (30%) chance of snow showers at night,
• Mostly sunny and cooler Sunday, then clear Sunday night.
• snow level 3,500 ft. today, 2,500 ft. tonight and Saturday, at the surface Saturday night, then free air freezing level at the surface Sunday and Sunday night.
• highs 33-17 lows 22-2.
• Sunny and a bit warmer Monday, mostly clear Monday night,
• Partly cloudy and a bit warmer Tuesday and at night,
• A mix of clouds and sun and a bit warmer with a  slight (20%) chance of showers and snow showers Wednesday,  partly cloudy with a slight (20%) chance of rain and snow showers Wednesday night,
• Then a mix of clouds and sun with a (40%) chance of snow and showers Thursday.
• free air freezing level at the surface Monday and Monday night, 4,000 ft. Tuesday, at the surface Tuesday night, snow level 2,500 ft. Wednesday, then 3,500 ft. Wednesday night and Thursday.
• highs 25-39 lows 10-22.

__________