Here is my weekly weather quiz question. What is the “Backwater Effect?” 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 High Pressure Ridge (“Arch”shape with blue arrows) is still dominating our weather picture. The graphics for days 3-7 show a couple of weak cold fronts moving in from the northwest next Saturday through Monday.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 77 in the Moderate category measuring Particulate Matter.

Oakridge: The Air Quality Index is 80 in the Moderate 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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Advisories:

• A RED FLAG WARNING IS IN EFFECT FOR ABUNDANT LIGHTNING ON DRY FUELS UNTIL 10 PM TONIGHT FOR THE WESTERN ROGUE BASIN INCLUDING THE ILLINOIS VALLEY, THE SISKIYOU MOUNTAINS, THE EASTERN ROGUE VALLEY, AND THE SOUTHERN OREGON CASCADES.
• A FIRE WEATHER WATCH IS IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR THE WESTERN ROGUE BASIN INCLUDING THE ILLINOIS VALLEY, THE SISKIYOU MOUNTAINS, THE EASTERN ROGUE VALLEY,  THE SOUTHERN OREGON CASCADES. THE KLAMATH BASIN,  THE FREMONT-WINEMA NATIONAL FOREST,  THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE AND WESTERN HARNEY COUNTIES.
• AN AIR  QUALITY ALERT IS IN EFFECT UNTIL 7 PM THIS EVENING FOR BENTON COUNTY, CLACKAMAS COUNTY, CLATSOP COUNTY, COLUMBIA COUNTY, HOOD RIVER COUNTY, LANE COUNTY, LINCOLN COUNTY, LINN COUNTY, MARION COUNTY, MULTNOMAH COUNTY, POLK COUNTY, TILLAMOOK COUNTY, WASHINGTON COUNTY, YAMHILL COUNTY,  CLARK COUNTY, DESCHUTTES COUNTY AND JEFFERSON COUNTY.
• AN AIR  QUALITY ALERT IS IN EFFECT UNTIL FURTHER NOTICE FOR CENTRAL DOUGLAS COUNTY, EASTERN CURRY COUNTY, JOSEPHINE COUNTY, THE EASTERN DOUGLAS COUNTY FOOTHILLS, JACKSON COUNTY, THE SOUTH CENTRAL OREGON CASCADES, THE SOUTHERN OREGON CASCADES, THE SISKIYOU MOUNTAINS, THE KLAMATH BASIN, NORTHERN AND EASTERN KLAMATH COUNTY, WESTERN, CENTRAL AND EASTERN LAKE COUNTY.
• AN AIR  QUALITY ALERT IS IN EFFECT UNTIL NOON WEDNESDAY FOR GILLIAM COUNTY, GRANT COUNTY, MORROW COUNTY, SHERMAN COUNTY, UMATILLA COUNTY, UNION COUNTY, WALLLOWA COUNTY, AND WHEELER COUNTY.
• AN AIR  QUALITY ALERT IS IN EFFECT UNTIL NOON SATURTDAY FOR DESCHUTES COUNTY AND JEFFERSON COUNTY.
• The Oregon Health Authority issued a Health Advisory today for Agency Lake, located just north of Klamath Falls along U.S. Highway 97 in Klamath County. Water monitoring has confirmed the presence of blue-green algae and the toxins they produce in the lake. These toxin concentrations can be harmful to humans and animals. People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue green or brownish red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur is discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified, or an advisory issued, can expose people to the toxins being produced. Although toxins are not absorbed through the skin, people who have skin sensitivities that come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Agency Lake at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• The Oregon Health Authority issued a Health Advisory today for Willow Creek Reservoir, located just east of the town of Heppner in Morrow County. Water monitoring has confirmed the presence of blue-green algae and the toxins they produce in the reservoir. These toxin concentrations can be harmful to humans and animals. People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue green or brownish red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur is discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified, or an advisory issued, can expose people to the toxins being produced. Although toxins are not absorbed through the skin, people who have skin sensitivities that come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Willow Creek Reservoir at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• The Oregon Health Authority issued a Health Advisory for Coffenbury Lake, located at Fort Stevens State Park about five miles northwest of US-101 ALT, Northwest Ridgefield Road near Warrenton in Clatsop County. Water monitoring has confirmed the presence of blue-green algae that can produce toxins in Coffenbury Lake. These blue-green algae levels are likely to be associated with dangerous cyanotoxin concentrations in the water that can be harmful to humans and animals.  People should always avoid areas with visible scum that looks foamy, scummy, thick like paint, pea-green, blue-green or brownish-red. Swimming and high-speed water activities such as water skiing or power boating where ingestion and inhalation exposure can occur are discouraged. Swallowing or inhaling water droplets as a result of these water activities in areas where a bloom has been identified or an advisory issued, can expose people to the toxins that can be produced. Although toxins are not absorbed through the skin, people with skin sensitivities who come into contact with a bloom may experience a puffy, red rash at the affected area. Drinking water directly from Coffenbury Lake at this time is especially dangerous. OHA Public Health Division officials advise campers and other recreational visitors that toxins cannot be removed by boiling, filtering or treating water with camping-style filters.
• 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:

• Partly cloudy and Hot today with more patchy smoke, partly cloudy with patchy smoke late tonight,
• Partly cloudy in the AM, mostly sunny and a bit cooler with patchy smoke Wednesday afternoon, partly cloudy with patchy smoke Wednesday night through Thursday AM, then partly cloudy in the afternoon through Friday night.
• highs 93-90 lows near 60.
• AM clouds, mostly sunny and a bit cooler Friday, partly cloudy at night,
• Then partly cloudy and a bit cooler Saturday through Monday,
• highs 86-84 lows 57-54. (seasonal averages high 84 low 52)

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Eugene-Springfield Pollen Count

Grass………. Low (3)
Trees………. Low (3)
Last Counted: 8/2/17
Data Courtesy of Oregon Allergy Associates.
Note: It would seem the pollen season is over.

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Forecast for Roseburg:

• Partly cloudy with patchy smoke and a slight (20%) chance of isolated thunderstorms this afternoon and tonight,
• Partly cloudy with patchy smoke with a slight (20%) chance of isolated thunderstorms Wednesday and in the evening, isolated thunderstorms late Wednesday night,
• Partly cloudy and a bit cooler with isolated thunderstorms Thursday and at night.
• highs near 95 lows near 63.
• Partly cloudy and a bit cooler with isolated thunderstorms Friday, just party cloudy at night,
• Partly cloudy and a bit warmer Saturday through Sunday, then partly cloudy with a slight (20%) chance of showers Sunday night and Monday (a bit cooler).
• highs 92-82 lows 60-57 warming back to 60 Monday. (seasonal averages high 86 low 56)

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

• Partly cloudy this afternoon at the shore while partly cloudy with patchy inland smoke and a slight (20%) chance of inland isolated thunderstorms and a bit cooler this afternoon and evening, patchy coastal fog late at night while patchy inland smoke tonight,
• Mostly cloudy with patchy AM coastal fog while patchy AM inland smoke Wednesday, partly cloudy with patchy inland smoke, just mostly cloudy at the shore at night while patchy evening inland smoke with a slight (20%) chance of isolated inland thunderstorms Wednesday night,
• Mostly cloudy with a slight (20%) of isolated thunderstorms in the AM, partly cloudy with a slight (20%) of isolated thunderstorms Thursday in the afternoon and evening, then just mostly cloudy late Thursday night.
• highs near 65 lows near 55.
• Partly cloudy and a bit cooler Friday through Sunday (a bit warmer Sunday), partly cloudy with a slight (20%) chance of showers Sunday night and Monday AM, then just partly cloudy and a bit cooler Monday afternoon.
• highs 64-66 cooling to 62 Monday lows 56-58. (seasonal averages high 65 low 53)

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Forecast for the Cascades in Lane County:

• Partly cloudy and a bit warmer with patchy smoke and a slight (20%) chance of showers and thunderstorms this afternoon and evening, partly cloudy with patchy smoke late tonight,
• Partly cloudy and a bit cooler with patchy smoke and a (30%) chance of showers and thunderstorms Wednesday afternoon and evening, a slight (20%) chance of showers and thunderstorms at night,
• Partly cloudy and a bit warmer with a slight (20%) chance of showers and thunderstorms Thursday afternoon and evening, then just partly cloudy late Thursday night.
• snow level above 8,000 ft. today through Thursday evening, then free air freezing level 12,000 ft. late Thursday night.
• highs 82-77 warming to 80 Thursday lows 57-55.
• Partly cloudy with a slight (20%) chance of afternoon showers and thunderstorms and a bit cooler Friday afternoon and evening, partly cloudy late at night,
• Partly cloudy with a slight (20%) chance of showers and thunderstorms Saturday afternoon and evening, partly cloudy late at night and Sunday, a bit cooler Sunday afternoon, a slight (20%) chance of showers and thunderstorms late Sunday night,
• Then partly cloudy and a bit cooler with a slight (20%) chance of showers and thunderstorms Monday.
• free air freezing level 12,000 ft. Friday AM, snow level above 8,000 ft. Friday afternoon and evening, free air freezing level above 12,000 ft. late Friday night and Saturday AM, snow level above 8,000 ft. Saturday afternoon and evening, free air freezing level above 12,000 ft. Saturday night through Sunday evening, then snow level above 8,000 ft. Late Sunday night and Monday.
• highs 76-70 lows 53-48.

 

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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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