Here is my weekly weather quiz question for the last time. What is an “Air Mass Thunderstorm?” Here is the correct answer. An Air Mass Thunderstorm: Generally, a thunderstorm not associated with a front or other type of synoptic-scale forcing mechanism. Air mass thunderstorms typically are associated with warm, humid air in the summer months; they develop during the afternoon in response to insolation, and dissipate rather quickly after sunset. They generally are less likely to be severe than other types of thunderstorms, but they still are capable of producing downbursts, brief heavy rain, and (in extreme cases) hail over 3/4 inch in diameter. I’ll have a new weekly weather quiz question for you starting Monday.  Please remember to post your answer at the bottom of this page. The first person to post the correct answer will win a week of free personalized weather forecasts tailored to your needs.  Good luck.

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The Upper Level High Pressure Ridge (Shaded “Arch” shape with blue arrows) that kept the Pacific Northwest dry is weakening . The graphic for days 1-3 shows a disturbance forming that will bring clouds and the chance of precipitation as it gets stuck as a stationary front. The graphic for days 3-7 shows a more complex frontal system building up and heading our way. For mountain snow conditions at the local ski areas check out their websites or give them a call.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 33 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 43 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 34 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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Home Wood Heating Advisory:

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)

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Advisories:

• AN AIR STAGNATION ADVISORY IS IN EFFECT UNTIL NOON TUESDAY FOR THE CENTRAL WILLAMETTE VALLEY, THE SOUTH WILLAMETTE VALLEY, THE NORTHERN OREGON CASCADE FOOTHILLS, AND THE CASCADE FOOTHILLS IN LANE COUNTY.
• AN AIR STAGNATION ADVISORY IS IN EFFECT UNTIL 1 PM MONDAY FOR CENTRAL DOUGLAS COUNTY.
• AN AIR STAGNATION ADVISORY IS IN EFFECT UNTIL 1 PM TUESDAY FOR EASTERN CURRY COUNTY, JOSEPHINE COUNTY, JACKSON COUNTY, THE KLAMATH BASIN, NORTHERN AND EASTERN KLAMATH COUNTY, AND CENTRAL, EASTERN AND WESTERN LAKE COUNTY.
• A Permanent Health Advisory remains in effect for the South Umpqua River and Lawson Bar. Pools in the bedrock along the rivers edge are known to develop Blue-green Algae (cyanobacterial) blooms that can be harmful to pets and people if accidental ingestion occurs. Signs have been posted along several access areas along the river.

 

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

• Mostly cloudy with areas of fog late tonight and Monday AM, just mostly cloudy and colder in the afternoon, cloudy with a good (50%) chance of rain late Monday night,
• Cloudy and a bit warmer with a good (50%) chance of rain Tuesday, a (40%) chance of evening rain, a (40%) chance of rain and snow at night (snow level 1,000 ft. late at night),
• Rain likely (70%) with a (40%) chance of snow Wednesday AM, a bit cooler with rain and snow likely (70%) in the afternoon (snow level 1,000 ft.) and Wednesday night (snow level 1,000 ft.).
• lows 34-36 cooling to 32 Wednesday night highs 42-48 cooling back to 42 Wednesday.
• Mostly cloudy and a bit cooler with rain and snow likely (70%) Thursday (snow level 1,000 ft.), rain likely (70%) with a (40%) chance of freezing rain Thursday night,
• AM rain likely (70%) with a (40%) chance of freezing rain Friday AM, rain likely (70%) and a bit warmer in the afternoon and Friday night,
• Mostly cloudy with a (30%) chance of AM rain, a bit warmer with a good (50%) chance of showers Saturday afternoon, a (40%) chance of showers at night,
• Then mostly cloudy and a bit warmer with a good (50%) chance of showers Sunday.
• highs 40-49 lows 34-38. (seasonal averages high 48 low 35)

 

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Forecast for Roseburg:

• Mostly cloudy with patchy fog and freezing fog late tonight and Monday AM, partly cloudy and a bit warmer in the afternoon, mostly cloudy with a slight (20%) chance of rain late at night,
• Cloudy with a slight (20%) chance of rain Tuesday (afternoon snow level 3,500 ft.), cloudy with a (30%) chance of  rain Tuesday night,
• Cloudy and a bit cooler with a (40%) chance of rain Wednesday, then rain likely (70%) Wednesday night.
• lows 35-38 highs 52-50.
• Cloudy with rain likely (70%) Thursday, rain at night,
• Mostly cloudy with rain likely (70%) Friday and Friday night,
• Mostly cloudy and a bit warmer with a (40%) chance of showers Saturday and at night,
• Then mostly cloudy with a (40%) chance of rain and a bit warmer Sunday.
• highs 50-54 lows 42-44 cooling back to 42 Saturday night. (seasonal averages high 51 low 37)

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

• Mostly cloudy with patchy fog late tonight and Monday AM, just mostly cloudy and a bit warmer in the afternoon, mostly cloudy Monday night with a slight (20%) chance of coastal showers late at night,
• Cloudy with a slight (20%) chance of rain and a bit cooler Tuesday, a (30%) of rain Tuesday night,
• Cloudy with a good (50%) chance of rain and a bit warmer Wednesday, then rain Wednesday night.
• lows 40-43 highs 56-52.
• Mostly cloudy with rain Thursday AM, rain likely (70%) and a bit cooler in the afternoon, rain Thursday night and Friday (a bit warmer), rain likely (70%) Friday night,
• Cloudy and a bit cooler with a good (50%) chance of showers Saturday, mostly cloudy with a good (50%) chance of showers at night,
• Then mostly cloudy and a bit warmer with a good (50%) chance of rain Sunday.
• highs 52-56 lows 44-46. (seasonal averages high 52 low 40)

 

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Forecast for the Cascades in Lane County:

• Mostly cloudy tonight,
• A mix of clouds and sun and a bit warmer Monday, mostly cloudy at night,
• Cloudy and cooler with a good (50%) chance of rain and snow Tuesday and Tuesday night,
• Cloudy with AM rain and snow likely (70%), snow likely (70%) with a (40%) chance of rain and a bit cooler Wednesday afternoon, then rain and snow likely (70%) Wednesday night.
• free air freezing level 7,500 ft. falling to 6,500 ft. late tonight, 8,000 ft. rising to 9,000 ft. Monday, 7,500 ft. falling to 6,500 ft. late Monday night, snow level 4,000 ft. Tuesday, 4,500 ft. Tuesday night, 3,500 ft. Wednesday, then 4,000 ft. Wednesday night.
• lows near 28 highs 45-36.
• Mostly cloudy with rain and snow likely (70%) and a bit cooler Thursday through Friday, rain and snow Friday night,
• Mostly cloudy with a good (50%) chance of AM rain and snow, a good (50%) chance of rain and snow Saturday afternoon and a bit warmer, a (40%) chance of rain and snow showers Saturday night,
• Then mostly cloudy and a bit warmer with a good (50%) chance of rain and snow Sunday.
•  snow level 4,000 ft. Thursday, then 5,000 ft. Thursday night through Sunday.
• highs 36-39 lows near 28.

 

 

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**Because weather forecasting is a combination of science, intuition, and timing there can be no absolute guarantees that individual forecasts will be 100% accurate. Nature is in a constant state of flux and sudden unexpected weather events can happen.

 

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Get your local Eugene-Springfield and Lane County news on-line at eugenedailynews.com.

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