Jul
31.
An Upper Level Low Pressure Trough (“U “Shape) keeps up the onshore airflow to control temperatures and cause mountain thunderstorms. The graphics for days 1-3 show no frontal systems moving into the Pacific Northwest. The graphics for days 3-7 Sunday through Thursday show a frontal system moving through the Pacific Northwest Sunday and another on Thursday.
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ADVISORIES:
- A RED FLAG WARNING IS IN EFFECT UNTIL 11 AM TONIGHT FOR THE CENTRAL MOUNTAINS OF OREGON, THE NORTHERN DESCHUTES NATIONAL FOREST, AND THE SOUTHERN DESCHUTES NATIONAL FOREST.
- A RED FLAG WARNING IS IN EFFECT UNTIL 11 PM TONIGHT FOR ABUNDANT LIGHTNING ON DRY FUELS FOR THE SOUTHERN OREGON CASCADES, THE KLAMATH BASIN AND THE FREMONT-WINEMA NATIONAL FOREST, AND THE SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN LAKE AND WESTERN HARNEY COUNTY.
- A RED FLAG WARNING IS IN EFFECT UNTIL 11 PM TONIGHT FOR THE BURNS BLM AND THE THE SOUTHERN GRASSLANDS.
- A RED FLAG WARNING IS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR THE CENTRAL CANYONLANDS, THE NORTHWESTERN VALE BLM, AND THE BAKER VALLEY.
- A RED FLAG WARNING FOR ABUNDANT LIGHTNING IS IN EFFECT UNTIL 11 PM TONIGHT FOR THE CENTRAL BLUE MOUNTAINS, THE SOUTHERN BLUE MOUNTAINS, AND THE WESTERN FORESTED BLUE MOUNTAINS.
HEALTH ADVISORIES:
- A PERMANENT HEALTH ADVISORY REMAINS IN EFFECT FOR THE SOUTH UMPQUA RIVER 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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Air Quality Index:
Eugene/Springfield: The Air Quality Index is 58 in the Moderate category measuring Particulate Matter.
Oakridge: The Air Quality Index is 34 in the Good category measuring Particulate Matter.
Cottage Grove: The Air Quality Index is 54 in the Moderate category measuring Particulate Matter.
Data courtesy of Lane Regional Air Protection Agency (LRAPA.org)
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Eugene-Springfield Area Pollen count:
GRASS: 5 MODERATE
TREES: 2 LOW
WEEDS: 0 ABSENT
Measured 7.31.25
Data courtesy of Oregon Allergy Associates.
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Forecast for the Southern and lower Mid Willamette Valley including Eugene-Springfield and Albany-Corvallis:
- Mostly cloudy this evening, clear tonight,
- Sunny and a bit warmer Friday, mostly clear Friday night,
- Sunny and a bit cooler Saturday, mostly clear in the evening, partly cloudy late at night,
- A mix of clouds and sun and a bit cooler Sunday, mostly cloudy in the evening, then partly cloudy late Sunday night.
- lows 55-52 highs 90-82.
- Mostly sunny Monday, partly cloudy Monday night,
- Sunny and a bit warmer Tuesday, mostly clear at night,
- Mostly sunny and as bit warmer Wednesday, partly cloudy in the evening, clear Wednesday night,
- Then mostly sunny Thursday.
- highs 82-88 lows 52-57. (seasonal averages high 86 low 52).
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Forecast for the Umpqua Valley including Roseburg:
- Partly cloudy late this evening, mostly clear late tonight,
- Sunny and a bit warmer Friday, mostly clear Friday night,
- Sunny and a bit cooler Saturday, mostly clear in the evening, partly cloudy late at night,
- Mostly cloudy and a bit cooler Sunday, then mostly cloudy Sunday night.
- lows 60-58 highs 88-90 cooling back to 88 Saturday.
- Some AM clouds, sunny and a bit warmer Monday afternoon, mostly clear Monday night,
- Some AM clouds, sunny and a bit warmer Tuesday afternoon, mostly clear at night,
- Partly cloudy start, sunny Wednesday afternoon, mostly clear Wednesday night,
- Then partly cloudy Thursday.
- highs 83-90 lows 56-60. (seasonal averages high 88 low 58).
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Forecast for The South Oregon Coast Including Coos Bay and North Bend:
- Partly cloudy this evening, mostly cloudy with patchy coastal fog late tonight,
- AM clouds with patchy fog, sunny and a bit warmer Friday afternoon, mostly clear in the evening, mostly cloudy with patchy fog late Friday night,
- Mostly cloudy with areas of AM coastal fog while patchy AM inland fog, sunny Saturday afternoon, partly cloudy in the evening, then mostly cloudy late Saturday night.
- lows near 55 highs near 72.
- Mostly cloudy and a bit cooler Sunday and Sunday night,
- Mostly cloudy start, sunny and a bit warmer Monday afternoon, partly cloudy with patchy fog late at night,
- Patchy AM fog, partly cloudy and a bit warmer Tuesday afternoon, partly cloudy Tuesday night,
- Partly cloudy and a bit warmer Wednesday, partly cloudy at night,
- Mostly cloudy start, then partly cloudy Thursday afternoon.
- highs 72-75 lows 53-58.
- (seasonal averages high 67 low 54). _______________
Forecast for the Northern Oregon Cascades including the Cascades in Lane County:
- Mostly cloudy this evening, partly cloudy late tonight,
- Mostly sunny and a bit warmer with a slight (20%) chance of showers Friday afternoon, partly cloudy with a slight (20%) chance of evening showers, mostly clear late Friday night,
- Sunny and a bit cooler Saturday, mostly clear in the evening, partly cloudy late Saturday night,
- A mix of clouds and sun and a bit cooler with a (40%) chance of showers and a slight (20%) chance of thunderstorms Sunday, then mostly cloudy with (40%) chance of showers and a slight (20%) chance of thunderstorms Sunday night.
- free air freezing level 13,000 ft. tonight, snow level above 8,000 ft. Friday and Friday night, 13,000 ft. Saturday and Saturday night, then snow level above 8,000 ft. Sunday and Sunday night,
- lows 49-44 highs 76-69.
- AM clouds and sun, mostly sunny with a slight (20%) chance of showers and a bit cooler Monday afternoon, just partly cloudy Monday night,
- Sunny and a bit warmer Tuesday, mostly clear at night,
- Then sunny and a bit warmer Wednesday and Thursday, partly cloudy Wednesday night.
- snow level above 8,000 ft. Sunday through Monday, free air freezing level 13,000 ft. Monday night through Tuesday night, 14,000 ft. Wednesday, then 15,000 ft. Wednesday through Thursday.
- highs 65-75 lows 44-43 warming to 49 Thursday.
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