Here is my weekly weather quiz question for the last time. What is the “Backwater Effect?” Here is the correct answer. The Backwater Effect in hydrologic terms, the effect which a dam or other obstruction has in raising the surface of the water upstream from it. 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 High Pressure Ridge (“Arch”shape with blue arrows) is still dominating our weather picture. The graphics for days 1-3 show a frontal system approaching the Pacific Northwest Sunday. An Upper Level Low Pressure Trough (Shaded “U”shape with blue arrows) will help change our weather pattern for next week. The graphics for days 3-7 show a frontal system approaching and then moving through  Oregon late next week.

Note: The Perseid Meteor Shower peaks this weekend from tonight through Sunday night. The moon will be about three quarters full so that will make viewing more difficult. Here cloud cover could be a problem as well as any residual smokey haze. Best viewing time will be after midnight and before dawn each night. Get away from the city lights and the sky won’t have the glow of city lights to obstruct your view.

 

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 13 in the Good category measuring Ozone.

Oakridge: The Air Quality Index is 72 in the Moderate category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 17 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 FOR ABUNDANT LIGHTNING AND OUTFLOW WINDS UNTIL 11 PM TONIGHT FOR THE CENTRAL MOUNTAINS OF OREGON, THE NORTHERN BLUE MOUNTAINS OF OREGO, THE SOUTHERN BLUE AND STRAWBERRY MOUNTAINS OF OREGON, AND FOR THE CENTRAL BLUE MOUNTAINS OF OREGON.
• A RED FLAG WARNING IS IN EFFECT FOR ABUNDANT LIGHTNING ON DRY FUELS FROM 2 PM UNTIL 11 PM TODAY FOR THE KLAMATH BASIN, THE FREMONT-WINEMA NATIONAL FOREST, THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE COUNTY, AND WESTERN HARNEY COUNTY.
• 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 has updated the Health Advisory issued July 28 for Howard Bay (also known locally as Howards Bay or Howard’s Bay), located in the southwest corner of Upper Klamath Lake, to include Shoalwater Bay to the north. These areas of Upper Klamath Lake are located off Oregon Route 140, 15 miles west of Klamath Falls in Klamath County. Water monitoring has confirmed the presence of blue-green algae and the toxins they produce in Howard Bay. 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 Howard Bay and Shoalwater Bay 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 Health Advisory 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:

• A mix of clouds and sun this afternoon, partly cloudy this evening, mostly cloudy with a good (50%) chance of rain late tonight (under 0.10 in. of rain possible),
• Cloudy with a good (50%) chance of AM showers (0.10 in. of rain possible), a mix f clouds and sun Sunday afternoon, partly cloudy at night,
• AM clouds and sun,  mostly sunny and a bit warmer Monday afternoon, then partly cloudy Monday night.
• highs 78-82 lows 55-52.
• Partly cloudy in the AM, mostly sunny and a bit warmer Tuesday afternoon, partly cloudy at night,
• Partly cloudy and a bit warmer Wednesday through Thursday AM, mostly sunny in the afternoon, partly cloudy Thursday night,
• Partly cloudy Friday AM, then mostly sunny and a bit warmer in the afternoon.
• highs 82-88 lows 52-55. (seasonal averages high 83 low 52)

 

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Eugene-Springfield Pollen Count

Grass………. Low (2)
Trees………. Low (3)
Last Counted: 8/10/17
Data Courtesy of Oregon Allergy Associates.
Note: It would seem the pollen season is over.

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Forecast for Roseburg:

• Mostly cloudy and a bit cooler with patchy smoke this afternoon, partly cloudy this evening, mostly cloudy with a slight (20%) chance of isolated showers late tonight,
• A slight (20%) chance of AM showers, mostly cloudy and a bit cooler Sunday afternoon and evening, mostly cloudy late Sunday night,
• AM clouds, sunny and a bit warmer Monday afternoon, mostly clear at night.
• highs near 84 lows 58-50.
• Partly cloudy in the AM, sunny and a bit warmer Tuesday afternoon, mostly clear at night,
• Mostly sunny and a bit warmer Wednesday and Thursday, mostly clear each night,
• Then sunny Friday.
• highs 86-94 lows 53-60. (seasonal averages high 86 low 56)

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

• Mostly cloudy this afternoon, mostly cloudy with a slight (20%) chance of scattered coastal showers late tonight while isolated inland showers late,
• Mostly cloudy with a (30%) chance of AM showers, mostly cloudy Sunday afternoon and at night,
• AM clouds with patchy coastal fog Monday, sunny in the afternoon, partly cloudy in the evening, then mostly cloudy late Monday night.
• highs near 64 lows 56-52.
• Mostly cloudy with patchy fog in the AM, sunny and a bit warmer Tuesday afternoon, mostly clear Tuesday night,
• Mostly sunny and a bit warmer Wednesday, partly cloudy Wednesday night and Thursday (a bit warmer), mostly clear at night,
• Then mostly sunny and a bit cooler Friday, mostly clear Thursday night.
• highs 68-73 cooling to 70 Friday lows 53-55. (seasonal averages high 65 low 53)

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Forecast for the Cascades in Lane County:

• Mostly sunny and a bit cooler this afternoon, partly cloudy tonight,
• Mostly cloudy with a good (50%) chance of AM showers, mostly cloudy with a slight (20%) chance of showers Sunday afternoon, just partly cloudy Sunday night,
• Partly cloudy in the AM, mostly sunny and a bit cooler Monday afternoon and at night.
• free air freezing level 13,000 ft. today, 14,000 ft. tonight, snow level above 8,000 ft. Sunday, free air freezing level 13,000 ft. Sunday night, 12,000 ft. rising to 13,000 ft. Monday, then 13,000 ft. Monday night.
• highs 74-65 warming to 68 Monday lows 49-45.
• Partly cloudy Tuesday AM, mostly sunny and a bit warmer in the afternoon, partly cloudy Tuesday night,
• Mostly sunny and a bit warmer Wednesday , Thursday, and Friday, partly cloudy to mostly clear at night.
• free air freezing level 13,000 ft. rising to 15,000 ft. Tuesday, 15,000 ft. Tuesday night through Wednesday night, 15,000 ft. rising to 16,000 ft. Thursday afternoon, then 16,000 ft. Thursday night and Friday.
• highs 68-76 lows 46-48.

 

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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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