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No winner this week. Here is my weekly weather quiz question for the last time. What is ANOMALOUS PROPAGATION or (AP) for short? (And no, it’s not a rare disease) This is the correct answer. “Anomalous Propagation” occurs when 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. To simplify that definition, “AP’” is also nicknamed “radar junk” which would be radar images that are not real precipitation. I’ll have another weekly weather quiz question for you starting Monday. Pease 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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An upper level trough of low pressure (shaded “U” shape) is sliding eastward through the Pacific Northwest. A frontal system has moved through Oregon, but fell apart with the result of not producing the expected precipitation. The next system can be seen off shore with its warm front moving ahead and the cold front will follow behind it. Yet another frontal system will move in by mid week to continue the rain chances and maybe even a snowflake or two down to the valley floor late Wednesday night, but I don’t expect any of it to stick enough to pile up any accumulation.
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Advisories: A WINTER WEATHER ADVISORY IS IN EFFECT FROM 6 PM THIS EVENING THROUGH 4 AM MONDAY EAST OF CASCADE LOCKS FOR THE WESTERN COLUMBIA RIVER GORGE AND UNTIL 10 AM MONDAY FOR THE UPPER HOOD RIVER VALLEY.
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Forecast for the Southern and lower Mid Willamette Valley including Eugene-Springfield and Albany-Corvallis: Patchy evening fog, rain tonight (0.25 in. of rain possible), rain Monday (0.25 in. of rain possible) and Monday night (0.10 in. of rain possible), cloudy with a good (50%) chance of rain Tuesday, a slight (20%) chance of rain in the evening, cloudy with rain likely (70%) Tuesday night and breezy (wind: S 10-15 mph shifting SW 15-25 mph late at night), rain Wednesday, evening showers, then rain and snow showers likely (70%) Wednesday night lows 37-43 cooling to 35 Wednesday night highs 50-52 cooling to 46 Wednesday. Mostly cloudy with a good (50%) chance of rain and snow showers Thursday through Friday, a (40%) chance of rain Friday night (snow level 1,000 ft.), a (40%) chance of showers Saturday (snow level 1,000 ft.), then mostly cloudy with a good (50%) chance of showers Saturday night and Sunday highs 42-40 warming to 45 Sunday lows 30-35. (seasonal averages high 46 low 34)
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Forecast for the Umpqua Basin including Roseburg: Mostly cloudy with rain tonight (0.10 in. of rain possible), rain Monday (0.15 in of rain possible), evening showers, a (40%) chance of showers late Monday night (0.10 in. of rain possible), mostly cloudy with a (30%) chance of showers Tuesday, rain late Tuesday night and Wednesday AM, rain and snow and colder in the afternoon, then rain and snow showers likely (70%) and colder Wednesday night lows 44-32 highs 47-54 cooling to near 44 Wednesday. Mostly cloudy with a (40%) chance of rain and snow showers Thursday, a good (50%) chance of rain and snow showers Thursday night and Friday, a (30%) chance of rain and snow showers Friday night and Saturday, then a good (50%) chance of rain and snow showers Saturday night and Sunday highs 40-45 lows 32-36. (seasonal averages high 49 low 36)
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Forecast for the South Oregon Coast including Coos Bay and North Bend: Mostly cloudy with rain tonight (0.25 in. of rain possible), rain Monday (0.40 in. of rain possible), evening coastal showers likely (60%) while evening showers inland and a (70%) chance of showers late Monday night (0.25 in. of rain possible), mostly cloudy with a (30%) chance of showers Tuesday, rain late Tuesday night and breezy (wind: S 20-25 mph at the beaches and S 10-15 mph inland), rain likely (60%) Wednesday AM, rain in the afternoon, then rain and snow showers likely (70%) and colder Wednesday night lows 47-37 highs 52-55 cooling to 44 Wednesday. Mostly cloudy with a good (50%) chance of rain and snow showers Thursday through Friday, then mostly cloudy with a (40%) chance of showers Friday night and Saturday, then a good (50%) chance of showers Saturday night and Sunday highs 42-49 lows 36-40. (seasonal averages high 51 low 40)
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Forecast for the Cascades of Lane County: Mostly cloudy with rain and snow likely (60%) this evening, rain and snow tonight (0.25 in. of rain possible, 1-4 in. of snow possible), rain and snow Monday AM, rain in the afternoon (0.50 in. of rain possible, 1-3 in. of snow possible), rain Monday night (0.25 in. of rain possible), mostly cloudy with a good (50%) chance of rain Tuesday, a (40%) chance of evening rain, rain likely (60%) late Tuesday night and breezy (wind: Sw 10-15 mph gusts to 30 mph increasing to S 15-25 mph gusts to 45 mph late at night), rain and snow Wednesday AM, snow in the afternoon, then mostly cloudy with snow showers Wednesday night snow level 3,000 ft. tonight, 5,500 ft. rising to 7,000 ft. Monday afternoon, 6,000 ft. Monday night and Tuesday, 6,500 ft. Tuesday night, 5,000 ft. Wednesday night, then at the surface Wednesday night lows 29-32 cooling to near 20 Wednesday night highs 38-32. Mostly cloudy with a good (50%) of snow showers Thursday through Friday, a (30%) chance of snow Friday night, a good (50%) chance of snow showers Saturday and Saturday night, then a (40%) chance of snow showers Sunday snow level at the surface Thursday through Sunday highs 23-28 lows 15-24.
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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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