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No winner this week. Here is my weekly weather quiz question for the last time. There are six different kinds of radar images. What are they? (Name as many as you can.)

There are six different types of images currently available for the RIDGE radar display: Base Reflectivity, Composite Reflectivity, Base Velocity, Storm Relative Motion, One-hour Precipitation and Storm Total Precipitation.

Base Reflectivity

This is a display of echo intensity (reflectivity) measured in dBZ (decibels of Z, where Z represents the energy reflected back to the radar). “Reflectivity” is the amount of transmitted power returned to the radar receiver. Base Reflectivity images are available at several different elevation angles (tilts) of the antenna and are used to detect precipitation, evaluate storm structure, locate atmospheric boundaries and determine hail potential.The base reflectivity image is from the lowest “tilt” angle (0.5°). This means the radar’s antenna is tilted 0.5° above the horizon. Learn more about Base Reflectivity.

Composite Reflectivity

This display is of maximum echo intensity (reflectivity) from any elevation angle at every range from the radar. This product is used to reveal the highest reflectivity in all echoes. When compared with Base Reflectivity, the Composite Reflectivity can reveal important storm structure features and intensity trends of storms. Learn more about composite reflectivity.

Base Velocity

This display of radial velocity represents the overall wind field. Green colors indicate wind moving toward the radar with red colors indicating wind moving away from the radar. The maximum range of this product is 124 nm (about 143 miles) from the radar location. Learn more about Base Velocity images.

Storm Relative Motion

This display is of radial velocity of the wind relative to the storm’s motion. The result is a picture of the wind as if the storms were stationary. This often unmasks storms that rotate (supercells) which can be a precursor to the formation of tornadoes. Green colors indicate wind moving toward the radar with red colors indicating wind moving away from the radar. The maximum range of this product is 124 nm (about 143 miles) from the radar location. Learn more about Storm Relative Motion images.

One-hour Precipitation

This is an image of estimated one-hour precipitation accumulation. This product is used to assess rainfall intensities for flash flood warnings, urban flood statements and special weather statements. The maximum range of this product is 124 nm (about 143 miles) from the radar location. This image will not display accumulated precipitation more distant than 124 nm, even though precipitation may be occurring at greater distances. To determine accumulated precipitation at greater distances you should link to an adjacent radar. Learn more about the one-hour precipitation image.

Storm Total Precipitation

This image is of estimated accumulated rainfall, continuously updated, since the last one-hour break in precipitation. This image is used to locate flood potential over urban or rural areas, estimate total basin runoff and provide rainfall accumulations for the duration of the event.The maximum range of this product is 124 nm (about 143 miles) from the radar location. This product will not display accumulated precipitation more distant than 124 nm, even though precipitation may be occurring at greater distances. To determine accumulated precipitation at greater distances link to an adjacent radar.

I’ll have a new weekly weather quiz question for you 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: NOT AT THIS TIME.

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An upper level trough of low pressure (“U” shape in blue arrows and shaded) off the coast is changing our weather as the high pressure ridge moves away starting the cool-down, and a frontal system will move in from the  Monday for a slight chance of light rain or drizzle. Another trough will move down from the Gulf of Alaska Monday, then high pressure will return for your Tuesday.

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Forecast for the Umpqua Basin including Roseburg: Partly cloudy this evening, mostly cloudy tonight, cloudy Sunday AM, partly cloudy in the afternoon and evening, cloudy with patchy fog late and a slight (20%) chance of showers Sunday night and Monday AM, partly cloudy with a slight (20%) chance of rain in the afternoon, mostly cloudy Monday evening, clearing at night, sunny Tuesday, then clear Tuesday night lows 52-42 highs 76-72 warming to 75 Tuesday. Sunny Wednesday through Friday with clear nights, then mostly sunny Saturday highs 85-90 cooling to near 82 Saturday lows 42-52. (seasonal averages high 81 low 53)

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Forecast for the South Oregon Coast including Coos Bay and North Bend: Mostly cloudy with patchy fog late tonight and Sunday AM, cloudy inland, mostly cloudy with a slight (20%) chance of coastal showers and some lingering fog Sunday afternoon, mostly cloudy with patchy fog and a slight (20%) chance of coastal showers Sunday night, patchy fog late inland too, cloudy with patchy AM fog and a slight (20%) chance of showers Monday, a slight (20%) chance of rain in the afternoon, mostly cloudy Monday night, partly cloudy Tuesday, clear in the evening then partly cloudy Tuesday night lows 52-45 highs 64-60. Partly cloudy and warmer Wednesday, mostly clear Wednesday night, then mostly sunny Thursday through Saturday with mostly clear nights highs 62-66 cooling to 63 Saturday lows 48-50. (seasonal averages high 66 low 51).

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Forecast for the Cascades of Lane County: Partly cloudy with a slight (20%) chance of thunderstorms this evening, partly cloudy and colder tonight, a mix of clouds and sun and much cooler Sunday, partly cloudy in the evening, mostly cloudy with a slight (20%) chance of rain late Sunday night, cloudy and cooler with a good (50%) chance of showers Monday AM, a slight (20%) chance of showers in the afternoon, partly cloudy and colder Monday night, mostly sunny Tuesday, then mostly clear Tuesday night free air freezing level 14,000 ft. tonight, 12,000 ft. Sunday, snow level above 8,000 ft. Sunday night and Monday, then free air freezing level 12,000 ft. Monday night through Tuesday night lows 42-32 warming to 35 Tuesday night highs 59-52 warming to near 70 Tuesday. Sunny and warmer Wednesday and Thursday and mostly clear at night, then mostly sunny Friday and Saturday with mostly clear skies Friday night free air freezing level 13,000 ft. Wednesday, then 14,000 ft. Wednesday night through Saturday highs 72-78 cooling to 72 Friday lows 35-46 cooling to near 70 Friday night.

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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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