Here is my weekly weather quiz question for the last time. What is  “Anomalous Propagation?” Here is the correct answer. ANOMALOUS PROPAGATION (AP): non-standard atmospheric temperature or moisture gradients will cause all or part of the radar beam to propagate along a non-normal path. When non-standard index-of-refraction distributions prevail, “abnormal” or “anomalous” propagation occurs. When abnormal downward bending occurs, it is called “superrefraction.” If the beam is refracted downward sufficiently, it will illuminate the ground and return signals to the radar from distances further than is normally associated with ground targets. The term “subrefraction” is applied when there is abnormal upward bending of the radar beam. Please remember to post your answer at the bottom of this page. I’ll have a new weekly weather quiz question for you starting Monday. The first person to post the correct answer will win a week of free personalized weather forecasts tailored to your needs.  Good luck.

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An Upper Level Low Pressure Trough (Shaded “U” shape with blue arrows) that changed our weather and some Winter precipitation is moving away. An Upper Level High (Shaded “Arch” shape with blue arrows) will dry us out for a short time. The graphic for days 1-3 shows another low moving southward along the Pacific Coast Sunday. The graphic for days 3-7 shows frontal movement a week from today bringing colder air from the North to the Pacific Northwest. For mountain snow conditions at the local ski areas check out their websites or give them a call.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 38 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 19 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 8 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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Home Wood Heating Advisory:

Eugene-Springfield: GREEN – Burning is Allowed.

Oakridge: GREEN – Burning is Allowed.

*Note: Pellet stoves may be used anytime if they produce no visible emissions.

Data courtesy of Lane Regional Air Protection Agency (LRAPA)

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Advisories:

• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 1 AM UNTIL 4 PM SUNDAY FOR THE COAST RANGE OF NORTHWEST OREGON AND THE NORTHERN OREGON CASCADE FOOTHILLS.
• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 4 AM UNTIL 7 PM SUNDAY FOR THE CENTRAL COAST RANGE OF WESTERN OREGON, THE CASCADE FOOTHILLS IN LANE COUNTY, AND THE CASCADES IN LANE COUNTY.
• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 1 AM UNTIL 7 PM SUNDAY FOR THE NORTHERN OREGON CASCADES.
• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 7 AM SUNDAY UNTIL 4 AM MONDAY FOR CENTRAL DOUGLAS COUNTY, EASTERN CURRY COUNTY, JOSEPHINE COUNTY, THE EASTERN DOUGLAS COUNTY FOOTHILLS, AND JACKSON COUNTY.
• A WINTER STORM WATCH IS IN EFFECT FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR CENTRAL DOUGLAS COUNTY, EASTERN CURRY COUNTY, JOSEPHINE COUNTY, THE EASTERN DOUGLAS COUNTY FOOTHILLS, AND JACKSON COUNTY.
• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 10 AM SUNDAY UNTIL 4 AM MONDAY FOR THE SOUTH CENTRAL OREGON CASCADES, THE SOUTHERN OREGON CASCADES, AND THE SISKIYOU MOUNTAINS.
• 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 and a bit warmer this afternoon, becoming mostly cloudy with a slight (20%) chance of rain late tonight (0.10 in. of rain possible),
• Mostly cloudy with AM rain and snow, rain and snow showers  and a bit cooler Sunday afternoon (0.50 in. of rain possible, snow level 1,000 ft.), cloudy with evening rain and snow showers likely (70%), a good (50%) chance of rain and snow showers late Sunday night (0.10 in. of rain possible),
• Mostly cloudy with a good (50%) chance of AM showers, showers likely (70%) and a bit warmer Monday afternoon, then mostly cloudy with a good (50%) chance of showers at night.
• highs 47-44 warming back to 47 Monday lows 34-36.
• Cloudy and a bit warmer with a good (50%) chance of showers Tuesday, mostly cloudy with a (40%) chance of showers Tuesday night,
• A mix of clouds and sun and a bit warmer with a slight (20%) chance of showers Wednesday, partly cloudy with a slight (20%) chance of showers Wednesday night,
• Just partly cloudy and a bit warmer Thursday, partly cloudy with a slight (20%) chance of rain at night,
• Then a mix of clouds and sun with a good (50%) chance of rain Friday.
• highs 48-50 lows near 37. (seasonal averages high 53 low 35)

 

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Forecast for Roseburg:

• Sunny and a bit warmer this afternoon, partly cloudy this evening,  mostly cloudy with a slight (20%) chance of rain late tonight,
• Mostly cloudy with AM rain and snow, rain and snow  showers and a bit cooler Sunday afternoon (0.25 in. of rain possible, 1-2 in. of snow lower elevations and 2-4 in. of snow above 1,500 ft., snow level 900 ft.), evening rain and snow showers, rain and snow showers likely (70%) at night (0.25 in. of rain possible, snow level 1,000 ft.),
• Mostly cloudy with AM rain and snow showers, rain and snow showers likely (70%) Monday afternoon,   then a (40%) chance of snow showers late Monday night.
• highs 48-42 warming to 45 Monday lows 33-35.
• Mostly cloudy and a bit warmer with a slight (20%) chance of rain and snow showers Tuesday, mostly cloudy with a slight (20%) chance of showers at night,
• Partly cloudy and a bit warmer Wednesday through Thursday night, then partly cloudy with a slight (20%) chance of rain and a bit warmer Friday.
• highs 52-54 lows 35-37. (seasonal averages high 55 low 38)

 

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

• Mostly sunny and a bit warmer this afternoon, mostly clear this evening at the shore and mostly cloudy with a slight (20%) chance of rain late tonight while mostly cloudy with slight (20%) chance of inland rain late tonight,
• Cloudy with AM coastal rain and coastal rain with a slight (20%) chance of afternoon thunderstorms while AM inland rain and snow with rain and snow showers and a bit cooler Sunday afternoon (0.50 in. of rain possible, snow level 1,500 ft. falling to 1,000 ft. in the afternoon), evening coastal showers with coastal showers likely (70%) late at night while inland evening rain and snow showers with inland showers late at night (0.25 in. of rain possible, snow 1,000 ft. rising to 1,500 ft. late Sunday night),
• Mostly cloudy with coastal showers Monday AM and showers likely (70%) in the afternoon while a good (50%) chance of AM inland rain and snow showers, a bit warmer with rain and snow showers likely (70%) in the afternoon, then mostly cloudy with a (40%) chance of rain and snow showers Monday night.
• highs 49-45 warming to 48 Monday lows 39-42.
• Mostly cloudy and a bit warmer with a slight (20%) chance of showers Tuesday and Tuesday night,
• Partly cloudy and a bit cooler Wednesday through Thursday night,
• Then partly cloudy and a bit warmer with a slight (20%) chance of rain Friday.
• highs near 53 lows 42-40 warming back to 42 Thursday night. (seasonal averages high 53 low 41)

 

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Forecast for the Cascades in Lane County:

• Mostly sunny and a bit warmer this afternoon, partly cloudy this evening, mostly cloudy with a (40%) chance of snow late tonight,
• Mostly cloudy with AM snow, a bit cooler with snow showers Sunday afternoon (3-6 in. of snow possible) snow showers at night,
• A bit cooler with snow showers likely (70%) Monday and Monday night.
• free air freezing level at the surface today, 3,500 ft. tonight, then snow level at the surface Sunday through Monday night.
• highs 33-28 lows near 20-22.
• Mostly cloudy with a good (50%) chance of snow showers Tuesday and a bit warmer, a slight (20%) chance of snow showers Tuesday night,
• A mix of clouds and sun with a slight (20%) chance of snow showers and a bit warmer Wednesday, partly cloudy with a slight (20%) chance of rain and snow showers at night,
• A mix of clouds and sun and a bit warmer Thursday, partly cloudy with a slight (20%) chance of rain and snow Thursday night,
• Then a mix of clouds and sun and a bit warmer with a good (50%) chance of rain or snow Friday.
• snow level at the surface Tuesday, 2,500 ft. Tuesday night and Wednesday, 3,500 ft. Wednesday night, free air freezing level 3,500 ft. Thursday, snow level 4,000 ft. Thursday night and Friday.
• highs 32-38  lows 22-24.

 

 

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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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