Here is my weekly weather quiz question for the last time. What is an “ Easterly Wave?” Here is the correct answer. An Easterly Wave is a low level disturbance of tropical origins. Easterly waves can develop into tropical cyclones. However, tropical cyclone development is not required in order for these systems to produce significant amounts of rainfall. The easterly waves are primarily a summer phenomenon. I’ll have a new weekly weather quiz question for you starting Monday. Please remember to post your answer as a comment by clicking on “no comments /comments” in the upper right hand portion of this page under the caption, then add your comment. The first person to post the correct answer will win a week of free personalized weather forecasts tailored to your needs. The answer has to be a comment to win. An email answer will not count. Good luck.

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Another upper level low is moving through the Pacific Northwest. A frontal system pushed in bringing cooler air in behind its cold front. Local skiers should be celebrating. The mountains have a lot of new snow and Willamette Pass, Hoodoo and Mt. Ashland are all open, with night skiing starting Monday December 21st at Hoodoo. Check their websites for updates.

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Air Quality Index:

Eugene-Springfield: The Air Quality Index is 8 in the Good category measuring Particulate Matter.

Oakridge: The Air Quality Index is 9 in the Good category measuring Particulate Matter.

Cottage Grove: The Air Quality Index is 13 in the Good category measuring Particulate Matter.

Data courtesy of Lane Regional Air Protection Agency (LRAPA).

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Advisories:

• A HIGH WIND WARNING IS IN EFFECT FROM 11 PM  TONIGHT THROUGH 6 AM SUNDAY NEAR THE BEACHES AND HEADLANDS FOR THE NORTH OREGON COAST AND THE CENTRAL OREGON COAST.
• A FLOOD WARNING CONTINUES FOR THE MOHAWK RIVER NEAR SPRINGFIELD, THE SIUSLAW NEAR MAPLETON, THE PUDDING RIVER NEAR AURORA, THE TUALATIN RIVER AT FARMINGTON, AND THE LUCKIEAMUTE RIVER NEAR SUVER.
• A FLOOD WARNING CONTINUES FOR  THE SOUTH FORK OF THE COQUILLE RIVER AT COQUILLE IN COOS COUNTY.
• A FLOOD WATCH IS IN EFFECT FOR THE ROGUE RIVER NEAR AGNESS, THE NORTH FORK OF THE COQUILLE RIVER NEAR MYRTLE POINT, THE SOUTH FORK OF THE COQUILLE RIVER AT MYRTLE POINT, ELK CREEK NEAR DRAIN, THE SOUTH UMPQUA RIVER AT TILLER, AND THE UMPQUA RIVER NEAR ELKTON.
• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 4 AM UNTIL 2 PM SUNDAY FOR THE NORTHERN OREGON CASCADE FOOTHILLS, THE NORTHERN OREGON CASCADES, THE CASCADES IN LANE COUNTY,
• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 2 AM UNTIL NOON SUNDAY FOR THE CENTRAL COLUMBIA RIVER GORGE AND THE UPPER HOOD RIVER VALLEY.
• A WINTER WEATHER ADVISORY IS IN EFFECT FROM 1 AM UNTIL 4 PM SUNDAY ABOVE 2,000 FT. FOR CENTRAL DOUGLAS COUNTY, EASTERN CURRY COUNTY, JOSEPHINE COUNTY, THE EASTERN DOUGLAS COUNTY FOOTHILLS, JACKSON COUNTY, THE SOUTH CENTRAL OREGON CASCADES, THE SOUTHERN OREGON CASCADES, THE SISKIYOU MOUNTAINS, THE KLAMATH BASIN, NORTHERN AND EASTERN KLAMATH COUNTY, AND CENTRAL, EASTERN, AND WESTERN LAKE COUNTY.
• A HEALTH ADVISORY CONTINUES FOR SUNSET BAY STATE PARK BEACH LOCATED IN COOS COUNTY FOR HIGHER-THAN-NORMAL FECAL BACTERIA WHICH CAN RESULT IN DIARRHEA, STOMACH CRAMPS, SKIN RASHES, UPPER RESPIRATORY INFECTIONS AND OTHER ILLNESSES. DIRECT CONTACT WITH THE WATER – ESPECIALLY BY CHILDREN AND THE ELDERLY, WHO MAY BE VULNERABLE TO WATERBORNE BACTERIA – SHOULD BE AVOIDED IN THIS AREA UNTIL THE ADVISORY IS LIFTED. VISITORS SHOULD AVOID WADING IN NEARBY CREEKS, POOLS OF WATER ON THE BEACH, OR IN DISCOLORED WATER AND STAY CLEAR OF WATER RUNOFF FLOWING INTO THE OCEAN.

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

• Cloudy with a good (50%) chance of rain this evening, rain likely (70%) late tonight (0.25 in. of rain possible),
• AM rain, showers Sunday afternoon (0.25 in. of rain possible), showers likely (70%) in the evening, rain Sunday night (0.25 in. of rain possible),
• Mostly cloudy and a bit warmer with rain, possibly heavy at times, Monday afternoon (1.00 in. of rain possible), rain at night and Tuesday, then rain likely (70%) Tuesday night (0.75 in. of rain possible).
• lows 39-43 cooling to 37 Tuesday night highs 46-52 cooling to 48 Tuesday.
• Mostly cloudy rain and a bit cooler Wednesday, rain likely (70%) and a bit cooler Wednesday night and Thursday, showers likely (70%) Thursday night (Christmas Eve),
• Mostly cloudy with a slight (20%) chance of rain and snow showers (snow level 1,500 ft.) Friday (Christmas Day), partly cloudy at night,
• Then a mix of clouds and sun and a bit warmer Saturday.
• highs 44-40 warming back to 44 Friday lows 36-30. (seasonal averages high 45 low 33)

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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.

Advisory Courtesy of Lane Regional Air Protection Agency (LRAPA).

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Forecast for Roseburg:

• Cloudy with a good (50%) chance of evening showers, rain and snow late tonight (0.10 in. of rain possible, 1 in. of snow possible, snow level 2,500 ft. falling to 2,000 ft. late tonight),
• Mostly cloudy with AM rain and snow, rain likely (70%) Sunday afternoon, (0.30 in. of rain possible, 1-2 in. of snow possible, snow level 2,000 ft. rising to 3,000 ft. in the afternoon), a (30%) chance of showers Sunday night (0.10 in. of rain possible, snow level 3,000 ft.),
• Mostly cloudy and a bit warmer Monday with rain, possibly heavy at times, (0.75 in. of rain possible, AM snow level 3,000 ft.) and breezy (Wind: S 10-15 mph increasing to S 15-25 mph in the afternoon) in the afternoon, rain, possibly heavy at times, in the evening, then rain Monday night (1.30 in. of rain possible) through Tuesday night.
• lows 39-47 cooling to 38 Tuesday night highs 46-42.
• Mostly cloudy and a bit warmer with rain and snow showers Wednesday, rain and snow at night and Thursday (a bit cooler), rain and snow showers Thursday night (Christmas Eve),
• Mostly cloudy with a (30%) chance of rain and snow showers Friday (Christmas Day), then just partly cloudy Friday night and Saturday.
• highs 50-42 lows 36-29. (seasonal averages high 47 low 36)

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Forecast for the South Oregon Coast including Coos Bay and North Bend:

• Mostly cloudy with evening coastal showers while inland evening showers likely (70%), rain likely (70%) late tonight (0.20 in. of rain possible) and breezy inland/shore (Wind: S 10-15 mph increasing to S 15-25 mph late at night inland while S 15-25 mph at the shore increasing to S 25-35 mph late tonight),
• Coastal rain Sunday while AM inland rain and rain likely (70%) in the afternoon (0.30 in. of rain possible) and windy at the shore (Wind: SW 20-30 mph shifting W 10-20 mph by late AM) breezy inland (Wind: SW 10-20 mph decreasing W 5-10 mph in the afternoon), cloudy with a good (50%) chance of evening coastal showers and rain likely (70%) at night while a (40%) of inland showers late at night (0.25 in. of rain possible),
• Rain, possibly heavy at times, a bit warmer Monday (1.80 in. of rain possible) and very windy (Wind: S 15-20 mph increasing to S 30-45 mph in the afternoon at the shore while S 10-15 mph increasing to S 20-30 mph inland in the afternoon, rain Monday night (1.15 in. of rain possible), possibly heavy at times, in the evening and breezy (Wind: SW 15-25 mph) ,
• Mostly cloudy with rain and breezy and a bit cooler Tuesday, then rain and cooler Tuesday night.
• lows 45-50 cooling to 43 Tuesday night highs 50-55 cooling to 52 Tuesday.
• Mostly cloudy with showers and a bit cooler Wednesday, rain Wednesday night and Thursday, showers at night (Christmas Eve),
• Mostly cloudy with a (40%) chance of showers Friday (Christmas Day), then just partly cloudy Friday night and Saturday.
• highs 49-46 warming to 50 Saturday lows 40-37. (seasonal averages high 51 low 39).

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Forecast for the Cascades in Lane County:

• Cloudy with a slight (20%) chance of  evening snow, snow likely (70%) late tonight (1-2 in. of snow possible),
• Mostly cloudy with AM snow, rain and snow showers and a bit cooler Sunday afternoon (0.50 in. of rain possible, 3-7in. of snow possible), rain and snow showers in the evening, snow likely (70%) late Sunday night,
• Mostly cloudy and a bit warmer with rain and snow Monday and breezy (Wind: SW 5-15 mph gusts to 25 mph increasing to SW 15-25 mph gusts to 50 mph in the afternoon), rain and snow, possibly heavy at times, Monday night and breezy (Wind: SW 5-15 mph gusts to 30 mph increasing to SW 15-25 mph gusts to 40 mph late at night),
• Rain and snow and breezy and a bit warmer Tuesday, then rain and snow Tuesday night.
• snow level 3,000 ft. today, at the surface tonight, 2,500 ft. Sunday, 3,000 ft. Sunday night, 3,000 ft. rising to 4,000 ft. Monday, then 5,000 ft. Monday night, 4,5000 ft. Tuesday, then 3,000 ft. Tuesday night.
• lows 23-28 cooling back to 23 Tuesday night highs 32-37.
• Mostly cloudy with snow and a bit cooler Wednesday through Thursday, cloudy with  snow showers likely (70%) Thursday night (Christmas Eve),
• Then mostly cloudy and a bit cooler with a slight (20%) chance of snow showers Friday (Christmas Day), a slight (20%) chance of snow Friday night,
• Then just partly cloudy and a bit warmer Saturday.
• snow level at the surface Wednesday through Friday night, then free air freezing level at the surface Saturday.
• highs 37-26 warming to 32 Saturday lows 22-16.

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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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