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No winner this week. Here is my weekly weather quiz question for the last time. What is a “gust front?” Here is the answer. A gust front is the leading edge of cool air rushing down and out from a thunderstorm. There are two main reasons why the air flows out of some thunderstoms so rapidly. The primary reason is the presence of relatively dry (low humidity) air in the lower atmosphere. This dry air causes some of the rain falling through it to evaporate, which cools the air. Since cool air sinks (just as warm air rises), this causes a down-rush of air that spreads out at the ground. The edge of this rapidly spreading cool pool of air is the gust front. The second reason is that the falling precipitation produces a drag on the air, forcing it downward. If the wind following the gust front is intense and damaging, the windstorm is known as a downburst. I’ll have another weekly weather quiz question for you starting next 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.
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Advisories: A HIGH SURF ADVISORY IS IN EFFECT UNTIL MIDNIGHT TONIGHT FOR THE NORTH AND CENTRAL OREGON COAST. A HIGH SURF ADVISORY IS IN EFFECT UNTIL 10 PM TONIGHT FOR THE SOUTH CENTRAL OREGON COAST.
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A trough of low pressure (“U” shape on the yellow line) has pushed a cold front through bringing back the rain, dropping snow levels , and even dropping some light snow showers to the valley floor. Another frontal system (position shown is Tuesday) will be sliding to the southeast bringing even more rain and snow. There will be a chance of more snow falling even down to the valley floor.
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Here are your detailed forecasts.**
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Forecast for the Southern and lower Mid Willamette Valley including Eugene-Springfield and Albany-Corvallis: Mostly cloudy with showers this evening, scattered rain or snow showers (snow level 1,000 ft., 0.10 in. of rain possible) late tonight, AM rain or snow showers, a good (50%) chance of rain or snow showers (0.15 in. of rain possible) Sunday afternoon, mostly cloudy with a (40%) chance of rain and snow showers in the evening, a slight (20%) chance of rain and snow showers (under 0.10 in. of rain possible) late Sunday night and colder, partly cloudy Monday and Monday night, mostly cloudy with a good (50%) chance of rain Tuesday AM (snow level 1,000 ft.), then mostly cloudy with showers Tuesday night lows 36-24 warming to near 35 Tuesday night highs near 45. Mostly cloudy with showers likely (60%) Wednesday and Wednesday night, a good (50%) chance of showers Thursday, a good (50%) chance of rain Thursday night, mostly cloudy with a good (50%) chance of rain Friday, then cloudy with a good (50%) chance of rain Friday night and Saturday highs 45-52 lows 36-40. (seasonal averages high 53 low 35)
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Forecast for the Umpqua Basin including Roseburg: Mostly cloudy with a (40%) chance of rain and snow showers tonight (snow level 1,500 ft. falling to 1,000 ft. late, under 0.10 in. of rain possible), mostly cloudy with a good (50%) chance of rain and snow showers (snow level 1,000 ft. rising to 1,500 ft.) Sunday, mostly cloudy in the evening, partly cloudy with a (30%) chance of rain and snow showers Sunday night (snow level 1,500 ft.), mostly cloudy Monday AM, partly cloudy in the afternoon and evening, mostly cloudy with a slight (20%) chance of rain and snow late Monday night and Tuesday AM, rain and snow in the afternoon and breezy, evening rain, then rain and snow late Tuesday night lows 30-38 highs 46-42 warming . Mostly cloudy with rain and snow showers Wednesday, rain and snow showers likely (60%) Wednesday night, rain and snow Thursday, rain and snow showers Thursday night, mostly cloudy with rain Friday, showers likely (60%) Friday night, then cloudy with showers Saturday highs 48-40 warming to 52 Friday lows near 38. (seasonal averages high 55 low 38)
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Forecast for the South Oregon Coast including Coos Bay and North Bend: Mostly cloudy with a (30%) chance of coastal showers and a (40%) chance of rain and snow showers inland (snow level 1,500 ft., under 0.10 in. of rain possible) tonight, a (30%) chance of coastal showers and a (40%) chance of inland rain and snow showers (under 0.10 in. of rain possible) Sunday, mostly cloudy in the evening and then partly cloudy with a (40%) chance of coastal showers and a (30%) chance of rain and snow showers inland Sunday night, AM mostly cloudy, partly cloudy Monday afternoon and evening, mostly cloudy with a good (50%) chance of rain coastal rain and a (40%) chance of rain and snow inland Monday night, mostly cloudy with rain likely (60%) Tuesday AM, rain and windy in the afternoon, then rain and breezy Tuesday night lows 35-32 warming to near 40 Tuesday night highs 46-49. Mostly cloudy with rain and snow showers Wednesday, showers Wednesday night, rain and snow Thursday, showers Thursday night, mostly cloudy with rain Friday, showers likely (60%) Friday night, then cloudy with a (40%) chance of showers Saturday highs 48-52 lows 40-42. (seasonal averages high 53 low 41).
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Forecast for the Cascades of Lane County: Mostly cloudy with snow showers this evening, snow showers (1-3 in. of snow possible) late tonight, scattered snow showers Sunday, a (40%) chance of show showers in the evening, a slight (20%) chance of snow showers Sunday night, a mix of clouds and sun Monday, just partly cloudy Monday night, a good (50%) chance of AM snow, snow likely (60%) Tuesday afternoon, then rain and snow showers Tuesday night snow level at the surface tonight through Sunday night, free air freezing level at the surface Monday and Monday night, snow level at the surface Tuesday, then 3,000 ft. Tuesday night lows 19-15 warming to near 22 Tuesday night highs 25-30. Mostly cloudy with snow showers likely (60%) Wednesday, rain and snow showers likely (60%) Wednesday night, snow showers likely (60%) Thursday, mostly cloudy with a good (50%) chance of snow Thursday night and Friday, then mostly cloudy with a good (50%) chance of rain and snow Friday night and Saturday snow level at the surface Wednesday, 2,500 ft. Wednesday night and Thursday, at the surface Thursday night, 3,000 ft. Friday, then 4,000 ft. Friday night and Saturday highs 25-40 lows 19-32.
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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 news on-line at Eugene Daily News.com.
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