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.

________________

 

An Upper Level High Pressure Ridge (“Arch”shape with blue arrows) is still dominating our weather picture. The graphics for days 3-7 show frontal systems moving in from the northwest Monday and Thursday. An Upper Level Low Pressure Trough (Shaded “U”shape with blue arrows) will help change our weather pattern for next week.

Note: The Perseid Meteor Shower peaks this weekend from Friday August 11th through Sunday August 13th. 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 Friday, Saturday and Sunday. Get away from the city lights and the sky won’t have the glow of city lights to obstruct your view.

 

________________

Air Quality Index:

Eugene-Springfield: The Air Quality Index is 117 in the Unhealthy for Sensitive Groups category measuring Particulate Matter.

Oakridge: The Air Quality Index is 94 in the Moderate category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 96 in the Moderate category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

 

__________________

Advisories:

• A RED FLAG WARNING IS IN EFFECT FOR ABUNDANT LIGHTNING ON DRY FUELS UNTIL 11 PM TONIGHT FOR THE WILLAMETTE NATIONAL FOREST.
• A RED FLAG WARNING IS IN EFFECT FOR ABUNDANT LIGHTNING AND GUSTY OUTFLOW WINDS UNTIL 10 PM FRIDAY FOR THE EAST SLOPES OF THE CENTRAL OREGON CASCADES, THE CENTRAL MOUNTAINS OF OREGON, 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 UNTIL 10 PM FRIDAY FOR THE DESCHUTES NATIONAL FOREST AND THE MINUS SISTERS RANGER DISTRICT, THE UMPQUA BASIN,  THE WESTERN ROGUE BASIN INCLUDING THE ILLINOIS VALLEY, THE SISKIYOU MOUNTAINS, THE EASTERN ROGUE VALLEY, AND THE SOUTHERN OREGON CASCADES.
• A RED FLAG WARNING IS IN EFFECT FOR ABUNDANT LIGHTNING ON DRY FUELS UNTIL 10 PM TONIGHT FOR THE UMPQUA BASIN,  THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE AND WESTERN HARNEY COUNTIES.
• AN AIR  QUALITY ALERT IS IN EFFECT UNTIL NOON FRIDAY 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, DESCHUTES COUNTY AND JEFFERSON COUNTY.
• AN AIR  QUALITY ALERT IS IN EFFECT UNTIL 11 PM FRIDAY FOR JACKSON COUNTY, THE SOUTH CENTRAL OREGON CASCADES, THE SOUTHERN OREGON CASCADES, AND THE SISKIYOU MOUNTAINS.
• AN AIR  QUALITY ALERT IS IN EFFECT UNTIL 11 AM SATURDAY FOR CROOK COUNTY, DESCHUTES COUNTY, GRANT COUNTY, WHEELER COUNTY, WASCO, JEFFERSON COUNTY, GILLAM COUNTY, MORROW COUNTY, SHERMAN COUNTY, UMATILLA COUNTY, UNION COUNTY, AND WALLOWA 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.

________________

 

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

• Partly cloudy with a slight (20%) chance of isolated showers and thunderstorms this evening, mostly cloudy with patchy smoke tonight,
• AM clouds, partly cloudy and a bit cooler with patchy smoke Friday afternoon and Friday night,
• Mostly cloudy Saturday AM, mostly sunny and a bit cooler in the afternoon, partly cloudy in the evening, mostly cloudy with a slight (20%) chance of rain late Saturday night and Sunday AM, mostly cloudy in the afternoon and evening, just partly cloudy late Sunday night.
• lows 56-54 highs 85-78.
• Partly cloudy and a bit warmer Monday through Thursday,
• highs 80-87 lows near 52. (seasonal averages high 84 low 52)

 

________________

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.

________________

Forecast for Roseburg:

• Partly cloudy with patchy smoke and a slight (20%) chance of  isolated thunderstorms this evening, patchy smoke late tonight,
• Partly cloudy and a bit cooler with patchy smoke and a slight (20%) chance of isolated thunderstorms Friday afternoon and at night,
• Sunny and a bit cooler with patchy smoke Saturday, partly cloudy with patchy evening smoke, partly cloudy with a slight (20%) chance of showers late Saturday night,
• Partly cloudy with a slight (20%) chance of AM showers, mostly cloudy and a bit cooler with a slight (20%) chance of showers in the afternoon and evening, partly cloudy late Sunday night.
• lows 59-57 warming to 60 Sunday night highs 90-85.
• Partly cloudy Monday and Monday night,
• Partly cloudy and a bit warmer Tuesday through Thursday AM, then sunny in the afternoon.
• highs 85-95 lows 56-60. (seasonal averages high 86 low 56)

_____________________

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

• Mostly cloudy with a slight (20%) chance of isolated inland thunderstorms, patchy fog late tonight,
• Mostly cloudy with patchy fog in the AM, partly cloudy Friday afternoon and evening, mostly cloudy with patchy fog late at night and Saturday AM, sunny in the afternoon, mostly cloudy with a slight (20%) chance of coastal showers late Saturday night,
• Mostly cloudy and a bit warmer with a slight (20%) chance of showers Sunday and in the evening, partly cloudy late at night.
• lows near 55 highs 63-67.
• Partly cloudy and a bit cooler Monday and Monday night,
• Partly cloudy and a bit warmer Tuesday through Thursday,
• highs 63-69 lows 53-56. (seasonal averages high 65 low 53)

________________

Forecast for the Cascades in Lane County:

• Partly cloudy with patchy smoke and a good (50%) chance of scattered showers and thunderstorms this evening, patchy smoke with a good (50%) chance of showers and thunderstorms late tonight (under 0.10 in. of rain possible, more in storms),
• Partly cloudy with patchy AM smoke and a (40%) chance of isolated showers and thunderstorms, patchy smoke and a (40%) chance of scattered showers and thunderstorms and a bit cooler Friday afternoon and evening, just partly cloudy late Friday night and Saturday AM, mostly sunny and a bit cooler with a slight (20%) chance of showers and thunderstorms Saturday afternoon, partly cloudy with a slight (20%) chance of rain late at night,
• Partly cloudy with a slight (20%) chance of AM showers,  mostly cloudy and a bit cooler Sunday afternoon, then just partly cloudy late Sunday night.
• snow level above 8,000 ft. tonight through Sunday, free air freezing level above 12,000 ft.
• lows 56-46 highs 77-66.
• Partly cloudy and a bit warmer Monday through Wednesday night,
• Then mostly sunny and a bit warmer Thursday.
• free air freezing level above 12,000 ft. Monday through Thursday.
• highs 68-75 lows 45-47.

 

________________

**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.

________________

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

________________