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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An approaching Upper Level High Pressure Ridge (Shaded “Arch” shape with blue arrows) helped push a frontal system through the Pacific Northwest. The graphic for days 3-7 shows more complex frontal systems heading our way early next week. 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 95 in the Moderate category measuring Particulate Matter.

Oakridge: The Air Quality Index is 126 in the Unhealthy for Sensitive Groups category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 67 in the Moderate 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:

• A DENSE FOG ADVISORY IS IN EFFECT UNTIL NOON TODAY FOR THE CENTRAL WILLAMETTE VALLEY AND THE SOUTH WILLAMETTE VALLEY.
• 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 SUNDAY 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 freezing fog this AM, a mix of clouds and sun and cooler with patchy lingering fog this afternoon, partly cloudy with patchy evening fog, areas of freezing fog late tonight and Sunday AM, a mix of clouds and sun and a bit warmer in the afternoon, mostly cloudy in the evening, partly cloudy with patchy fog late Sunday night,
• Patchy AM fog, then mostly cloudy and a bit warmer Monday and at night.
• highs 43-49 lows 29-35.
• Mostly cloudy and a bit cooler with a slight (20%) chance of rain Tuesday, cloudy with a good (50%) chance of rain Tuesday night and Wednesday, then mostly cloudy with rain likely (70%) Wednesday night through Friday.
• highs 48-50 lows 35-37. (seasonal averages high 49 low 35)

 

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Forecast for Roseburg:

• Partly cloudy with areas of fog this AM, partly cloudy and a bit warmer this afternoon, mostly clear this evening, partly cloudy with patchy fog late tonight,
• Mostly cloudy with patchy fog Sunday AM, partly cloudy and a bit cooler in the afternoon, mostly cloudy with patchy fog and freezing fog Sunday night,
• Mostly cloudy with patchy AM fog and freezing fog Monday, then just partly cloudy in the evening, mostly cloudy at night.
• highs 52-50 lows 34-36.
• Mostly cloudy with a (40%) chance of rain and a bit cooler Tuesday, cloudy with a (40%) chance of  rain Tuesday night,
• Then mostly cloudy with rain likely (70%) Wednesday through Friday.
• highs 52-50 lows 37-42. (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 coastal fog while areas of inland fog this AM, partly cloudy this afternoon, mostly clear this evening, partly cloudy with patchy fog late tonight,
• Partly cloudy with patchy AM fog, mostly cloudy Sunday afternoon and at night with patchy fog late,
• Patchy AM fog, then mostly cloudy Monday and at night.
• highs near 56 lows 37-40.
• Mostly cloudy with a slight (20%) chance of rain and a bit cooler Tuesday, rain likely (70%) Tuesday night and Wednesday, rain Wednesday night,
• Rain and breezy Thursday and at night,
• Then mostly cloudy with rain likely (70%) Friday.
• highs 54-52 lows 42-46. (seasonal averages high 52 low 40)

 

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Forecast for the Cascades in Lane County:

• Partly cloudy today through Sunday, mostly cloudy Sunday night,
• A mix of clouds and sun Monday, then partly cloudy Monday night.
• free air freezing level 8,000 ft. today, 9,000 ft. tonight, 9,000 ft. rising to 10,000 ft. Sunday afternoon, 8,000 ft. falling to 7,500 ft. Sunday night, 8,000 ft. rising to 9,000 ft. Monday, then 7,000 ft. Monday night.
• highs near 44 lows 26-32 cooling to 25 Monday night.
• Mostly cloudy and a bit cooler with a slight (20%) chance of rain and snow Tuesday, cloudy with a good (50%) chance of rain and snow Tuesday night,
• Cloudy and a bit cooler with a good (50%) chance of rain and snow Wednesday, then rain and snow likely (70%) Wednesday night through Friday (a bit cooler).
• snow level 6,000 ft. Tuesday, 5,500 ft. Tuesday night, 4,500 ft. Wednesday, 5,000 ft. Wednesday night, 4,500 ft. Thursday, 5,000 ft. Thursday night, then 4,500 ft. Friday.
• highs 39-36 lows 26-30 cooling back to 26 Thursday night.

 

 

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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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