Here is my weekly weather quiz question for the last time. What is a “Baroclinic leaf shield?” Here is the correct answer. A Baroclinic leaf shield is a cloud pattern on satellite images – frequently noted in advance of formation of a low pressure center. I’ll have a new weekly weather quiz question for you starting Monday. The first person to post the correct answer as a comment on this page will win a week of free personalized weather forecasts tailored to your needs.  Good luck.

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An Upper Level Low Pressure Trough (Shaded “U”shape with blue arrows) will keep enough moisture available for possible showers and thunderstorms in the mountains, the coast and to the south of Lane county. The graphics for days days 1-3 show a weak frontal system that moved through today to cool us down a bit. The graphics for days 3-7 show a frontal system trying to make an impact on us Thursday and another approaching the coast next Monday.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 34 in the Good category measuring Ozone.

Oakridge: The Air Quality Index is 16 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 31 in the Good category measuring Ozone.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

 

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Advisories:

• A RED FLAG WARNING IS IN EFFECT UNTIL 11 PM TONIGHT FOR ABUNDANT LIGHTNING WITH DRY FUELS FOR THE UMPQUA NATIONAL FOREST, THE SOUTHERN OREGON CASCADES, THE KLAMATH BASIN, AND THE FREMONT-WINEMA NATIONAL FOREST. THAT INCLUDES NORTHERN, EASTERN, AND WESTERN KLAMATH COUNTY, WESTERN LAKE COUNTY, EASTERN DOUGLAS COUNTY, EASTERN JACKSON COUNTY, THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE AND WESTERN HARNEY COUNTIES.
• A RED FLAG WARNING IS IN EFFECT FROM 2 PM UNTIL 11 PM MONDAY FOR THE DESCHUTES NATIONAL FOREST, THE  MINUS SISTERS RANGE DISTRICT. THE CENTRAL MOUNTAINS OF OREGON, AND THE SOUTHERN BLUE AND STRAWBERRY MOUNTAINS AND THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE AND WESTERN HARNEY COUNTIES.
• A FIRE WEATHER WATCH IS IN EFFECT FROM LATE MONDAY MORNING THROUGH MONDAY EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR THE KLAMATH BASIN, THE FREMONT-WINEMA NATIONAL FOREST, THE SOUTHERN OREGON CASCADES, THE EASTERN ROGUE VALLEY, AND FOR THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE AND WESTERN HARNEY COUNTIES, AND NEARLY ALL OF THE WILLAMETTE NATIONAL FOREST..
• The Oregon Health Authority has updated the health advisory issued June 30 for Lake Billy Chinook, located about 12 miles west of Madras in Jefferson County. The update lifts the advisory on those areas of the Deschutes and Crooked River of Lake Billy Chinook arms affected by the advisory, and confines the advisory on the Metolius Arm to Perry South Cove. Water monitoring has confirmed that the level of blue-green algae toxins are below guideline values for human exposure. However, OHA recommends that people remain cautious when using the lake, particularly with pets because toxins are still well above the very low exposure levels established for dogs.
• 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:

• Clear tonight,
• Mostly sunny Monday, partly cloudy at night,
• Partly cloudy Tuesday and Tuesday night,
• AM clouds, mostly sunny and a bit cooler Wednesday afternoon, clear in the evening, partly cloudy late at night.
• lows 54-58 cooling back to 54 Wednesday night highs 88-86.
• Mostly sunny and a bit cooler Thursday, mostly clear at night,
• Mostly sunny Friday, mostly clear Friday night,
• Sunny and a bit warmer Saturday and Sunday, mostly clear at night.
• highs 84-89 lows near 52. (seasonal averages high 84 low 52)
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Eugene-Springfield Pollen Count
Grass………. Moderate (9)
Trees………. Low (5)
Last Counted: 7/20/17
Data Courtesy of Oregon Allergy Associates.
Note: It would seem the pollen season just about over.

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Forecast for Roseburg:

• Partly cloudy with a slight (20%) chance of thunderstorms tonight,
• Partly cloudy with a slight (20%) chance of thunderstorms Monday and at night,
• Partly cloudy and a bit cooler with a slight (20%) chance of thunderstorms Tuesday and Tuesday night,
• Partly cloudy in the AM, sunny and a bit warmer Wednesday afternoon, then mostly clear at night.
• lows near 62 highs 94-86.
• Sunny and a bit warmer Thursday, clear Thursday night,
• Sunny and a bit warmer Friday, clear at night,
• Sunny Saturday, clear Saturday night,
• Then sunny and a bit warmer Sunday.
• highs 89-86 lows 59-57. (seasonal averages high 86 low 57)

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

• Mostly clear this evening, partly cloudy late tonight,
• Mostly cloudy Monday AM, sunny in the afternoon, partly cloudy in the evening, cloudy late Monday night,
• Mostly cloudy in the AM, partly cloudy and a bit cooler Tuesday with a slight (20%) chance of inland thunderstorms in the afternoon and evening, mostly cloudy late at night,
• Mostly cloudy in the AM, mostly sunny Wednesday afternoon, then mostly clear Wednesday night.
• lows 56-58 cooling back to 56 Tuesday night highs 66-63.
• Mostly sunny and a bit warmer Thursday, partly cloudy at night through Saturday, mostly clear at night,
• Then mostly sunny and a bit warmer Sunday.
• highs 63-66 lows near 54. (seasonal averages high 65 low 53)

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Forecast for the Cascades in Lane County:

• Partly cloudy with a slight (20%) chance of showers and thunderstorms tonight and Monday AM, a (40%) chance of showers and thunderstorms in the afternoon (under 0.10 in. of rain possible, more in storms), a (30%) chance of evening showers and thunderstorms, a slight (20%) chance of showers and thunderstorms late Monday night and Tuesday AM, a bit warmer with a (40%) chance of showers and thunderstorms in the afternoon, a (30%) chance of evening showers and thunderstorms, a slight (20%) chance of showers and thunderstorms Tuesday night,
• Partly cloudy with a slight (20%) chance of AM showers and thunderstorms, mostly sunny Wednesday and a bit cooler in the afternoon, then mostly clear at night.
• snow level above 8,000 ft. tonight through Wednesday AM, then free air freezing level above 14,000 ft. Wednesday afternoon and Wednesday night.
• lows 54-50 highs 75-82.
• Mostly sunny and a bit cooler Thursday, mostly clear Thursday night,
• Then mostly sunny and a bit warmer Friday, Saturday, and Sunday, mostly clear each night.
• free air freezing level above 12,000 ft. Thursday through Sunday.
• highs 75-82 lows near 50.

 

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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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