May
12.
Here is my weekly weather quiz question for the last time. “What is “Relative Humidity?” Here is the correct answer. Relative Humidity is a dimensionless ratio, expressed in percent, of the amount of atmospheric moisture present relative to the amount that would be present if the air were saturated. Since the latter amount is dependent on temperature, relative humidity is a function of both moisture content and temperature. As such, relative humidity by itself does not directly indicate the actual amount of atmospheric moisture present. See dew point.
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An Upper Level High Pressure Ridge (“Arch” shape ) is taking slowly tilting and moving to the east enhancing cooling. The graphics for days 1-3 show weak frontal waves moving across Oregon Monday and Tuesday for cooling. The graphics for days 3-7 Wednesday through Sunday show a frontal system sliding through Oregon between Thursday and Friday and another frontal system to our northwest Sunday.
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Air Quality Index:
Eugene/Springfield: The Air Quality Index is 38 in the Good category measuring Ozone.
Oakridge: The Air Quality Index is 20 in the Good category measuring Particulate Matter.
Cottage Grove: The Air Quality Index is 24 in the Good category measuring Particulate Matter.
Data courtesy of Lane Regional Air Protection Agency (LRAPA)
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ADVISORIES:
- NONE AT THIS TIME
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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Forecast for the Southern and lower Mid Willamette Valley including Eugene-Springfield and Albany-Corvallis:
- Mostly clear tonight,
- Mostly sunny and a bit cooler Monday, partly cloudy in the evening, mostly clear late Monday night,
- Sunny and a bit warmer Tuesday, clear at night,
- Sunny and a bit warmer Wednesday, then clear Wednesday night.
- lows 47-52 highs 73-80.
- Sunny and a bit cooler Thursday and Friday, clear both nights,
- Sunny and a bit cooler Saturday, mostly clear Saturday night,
- Then sunny and a bit warmer Sunday.
- highs 79-70 warming to 73 Sunday lows 47-43 warming to 45 Saturday night (seasonal averages high 68 low 44)
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EUGENE-SPRINGFIELD POLLEN COUNT:
GRASS: HIGH (20)
TREES: MODERATE (65)
WEEDS: LOW (9)
Measured 5.12.24
Data courtesy of Oregon Allergy Associates.
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Home Wood Heating Advisory:
Eugene-Springfield: GREEN- Burning wood in wood stoves or fireplaces is allowed.
Oakridge: GREEN- Burning wood in wood stoves or fireplaces is allowed.
*Pellet stoves can be used anytime since they don’t produce the particulate smoke.
Data courtesy of Lane Regional Air Protection Agency (LRAPA)
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Forecast for the Umpqua Valley including Roseburg:
- Mostly clear tonight,
- Some AM clouds, sunny and a bit cooler Monday afternoon, mostly clear in the evening, partly cloudy late Monday night,
- Some AM clouds, sunny Tuesday afternoon, clear at night,
- Sunny and a bit warmer Wednesday, then clear Wednesday night.
- lows 52-50 warming back to 54 Wednesday night highs 77-85.
- Sunny and a bit cooler Thursday and Friday, mostly clear both nights,
- Mostly sunny and a bit warmer Saturday, mostly clear at night,
- Then mostly sunny Sunday.
- highs 83-73 warming to 76 Sunday lows 52-45 warming to 47 Saturday night. (seasonal average high 71 low 47)
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Forecast for The South Oregon Coast Including Coos Bay and North Bend:
- Becoming mostly cloudy late tonight,
- AM clouds, sunny and a bit warmer Monday afternoon, partly cloudy Monday night,
- Some AM clouds, sunny and a bit warmer Tuesday afternoon, mostly clear at night,
- Mostly sunny and a bit warmer Wednesday, then mostly clear Wednesday night.
- lows 46-48 highs 63-70.
- Mostly sunny and a bit cooler Thursday, Friday and Saturday, mostly clear each night,
- Then mostly sunny and a bit warmer Sunday.
- highs 66-62 warming to warming to 64 Saturday lows 47-45 warming back to 47 Saturday night. (seasonal average high 60 low 48)
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Forecast for the Northern Oregon Cascades including the Cascades in Lane County:
- Mostly clear tonight,
- Sunny and a bit cooler Monday, partly cloudy in the evening, mostly clear late Monday night,
- Then sunny and a bit warmer Tuesday and Wednesday, clear both nights.
- free air freezing level 12,000 ft. falling to 11,000 ft. late tonight, 11,000 ft. Monday, 12,000 ft. Monday night, 13,000 ft. Tuesday through Wednesday, then 14,000 ft. Wednesday night.
- lows 40-38 warming to 44 Wednesday night highs 62-70.
- Sunny and a bit cooler Thursday, Friday and Saturday, mostly clear each night,
- Then sunny and a bit warmer with a slight (20%) chance of rain Sunday.
- free air freezing level 14,000 ft. Thursday and Thursday night, 13,000 ft. Friday, 10,000 ft. Friday night, 6,500 ft. Saturday, 9,000 ft. Saturday night, then snow level 6,500 ft. Sunday.
- highs 69-60 warming to 63 Sunday lows 42-35 warming to 37 Saturday night.
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