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We have a winner!

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Congratulations to Lee Ann Thomlpson who was the first person to post the correct answer to my weather quiz question this week. Here is the question again. In the Fall the leaves change colors and fall from the trees. What causes the leaves to change colors? Here is Lee Ann’s answer. “As the length of the day changes and the amount of light reduces, the leaves of trees can no longer efficiently use photosynthesis to produce the energy for growth. As the trees stop the process, the green in the leaves disappears leaving behind the fall colors of orange, red, yellow and brown.” This is the full detailed explanation: During the spring and summer the leaves have served as factories where most of the foods necessary for the tree’s growth are manufactured. This food-making process takes place in the leaf in numerous cells containing chlorophyll, which gives the leaf its green color. Along with the green pigment are yellow to orange to red pigments as well. Most of the year these colors are masked by great amounts of green coloring. But in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange to red colors become visible and give the leaves part of their fall splendor. The best time to enjoy the autumn color would be on a clear, dry, and cool day.

I’ll have another weather quiz question or you starting next Monday. Please post your answer as a comment by clicking on “no 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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The jet stream shows a trough of low pressure ( “U” shaped area) swinging through the Pacific Northwest with another one following behind it. A weak, short lived high pressure ridge (small “Arch” shape moving over us) stopped the rain and brought more sunshine at least temporarily. We’ll see another  frontal system (shown offshore) move in Tuesday followed by another Wednesday and Wednesday night. It’s been a long time coming, but a high pressure ridge (“arch” shape shown at the end of the jet stream movie) will build in late in the week warming us up a bit so it will feel more like Spring. It’s about time. It looks like the rain will still hang around though.

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Advisories: A WINTER WEATHER ADVISORY IS IN EFFECT FROM 11 PM TONIGHT UNTIL 5 PM TUESDAY FOR THE NORTH OREGON CASCADES, NOT INCLUDING THE CASCADES OF LANE COUNTY.

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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: Cloudy with a (40%) chance of evening rain, rain late tonight (0.10 in. of rain possible), and Tuesday (0.10 in. of rain possible), rain Tuesday night (0.25 in. of rain possible), mostly cloudy with a good (50%) chance of rain Wednesday (0.10 in. of rain possible), a slight (20%) chance of rain Wednesday night, just mostly cloudy Thursday, mostly cloudy with a slight (20%) chance of showers Thursday night lows 40-47  falling to 42 Thursday night highs 60-54. Mostly cloudy with a (40%) chance of showers Friday, and (30%) Friday night through Saturday night, partly cloudy with a slight (20%) chance of showers Sunday and Monday, and mostly cloudy with a slight (20%) chance of showers Sunday night highs 60-54 lows 42-38. (seasonal  averages high 58 low 37)

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Forecast for the Umpqua Basin including, Roseburg:  Cloudy with a good (50%) chance of rain this evening, rain late tonight through Tuesday evening, rain likely (60%) late Tuesday night, a (30%) chance of rain Wednesday, then partly cloudy Wednesday night through Thursday night, mostly cloudy with a (30%) chance of showers and cooler Friday  and Friday night lows 42-49 falling to 42 Friday night highs 56-67 cooling to near 60 Friday. Mostly cloudy with a slight (20%) chance of showers Saturday and Saturday night, partly cloudy with a slight (20%) chance of rain and snow showers Sunday, a slight (20%) chance of showers Sunday night, then partly cloudy with a slight (20%) chance of showers Monday highs 55-64 lows 37-40. (seasonal averages high 61 low 39)

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Forecast for the South Oregon Coast including Coos Bay and North Bend: Cloudy with a good (50%) chance of evening rain, then rain late tonight and Tuesday, coastal rain Tuesday night with rain likely (60%) inland, a (30%) chance of rain Wednesday,  just partly cloudy Wednesday night and Thursday, partly cloudy Thursday, mostly cloudy with a slight (20%) chance of rain Thursday night, then a (40%) chance of showers Friday and  Friday night lows 44-50 falling to 43 Friday night highs 55-61 cooling to 54 Friday Mostly cloudy with a slight (20%) of showers Saturday, partly cloudy with a slight (20%) chance of showers Saturday night and Sunday, then mostly cloudy with a slight (20%) chance of showers Sunday through Monday highs 50-56  lows 40-42. (seasonal averages high 56 low 42).

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Forecast for the Cascades of Lane County: Mostly cloudy with a good (50%) chance of snow and rain this evening, snow tonight, snow Tuesday AM, rain and snow Tuesday afternoon (1-3 in. of snow possible), rain Tuesday night (2 in. of snow possible, 0.50 in. of rain possible) and windy (wind: SW 20-30 mph gusts to 45 mph late),  a (40%) chance of rain Wednesday (0.25 in. of rain possible) and windy (wind: W 25-35 mph gusts to 50 mph), a slight (20%) chance of showers Wednesday night and windy (wind: W 25-30 mph switching to 10-15 mph late), then a slight (20%) chance of rain Thursday and (30%) Thursday night snow level 3,000 ft. falling to 2,500 ft. late tonight, 2,500 ft. rising to 4,000 ft. Tuesday afternoon, 6,000 ft. rising to 7,000 ft. late Tuesday night, 8,000 ft. Wednesday, and 7,000 ft. Wednesday night, 8,000 ft. Thursday and 7,000 ft. Thursday night  lows 30-38  highs 40-50. Mostly cloudy with a good (50%) chance of  showers Friday, a (40%) chance of rain and snow showers Friday night through Saturday night, partly cloudy with a slight (20%) chance of rain and snow showers Sunday, mostly cloudy with a slight (20%) chance of rain and snow showers Sunday night, then partly cloudy with a slight (20%) chance of showers Monday snow level 7,000 ft. Friday, 4,000 ft. Friday night and Saturday, 3,000 ft. Saturday night, and  4,000 ft. Sunday, 4,500 ft. Sunday night, and 5,500 ft. Monday highs 50-40 and back to 48 Monday lows 32-28.

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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.