Here is my weekly weather quiz question for the last time. What is a “Tornado Vortex Signature “? Here is the correct answer. A Tornado Vortex Signature is an image of a tornado on the Doppler radar screen that shows up as a small region of rapidly changing wind speeds inside a mesocyclone. The following velocity criteria is normally required for recognition: velocity difference between maximum inbound and outbound (shear) is greater than or equal to 90 knots at less than 30 nmi and is greater than or equal to 70 knots between 30 and 55 nmi. It shows up as a red upside down triangle on the Storm Relative Velocity Display. Existence of a TVS strongly increases the probability of tornado occurrence, but does not guarantee it; therefore, the feature triggering it must be examined closely by the radar operator. A TVS is not a visually observable feature.
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An Upper Level High Pressure Ridge (“Arch” shape) continues sending moisture to the Pacific Northwest. The graphics for days 1-3 show a little frontal over the Pacific Northwest. The graphics for days 3-7 Wednesday through Sunday show frontal activity continuing through the period.
Note: Ski Report: Willamette Pass, Hoodoo, and Mt. Ashland are all open for the ski season. Check their Web sites for specific mountain conditions and hours of operation.
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ADVISORIES:
- A WINTER STORM WARNING IS IN EFFECT UNTIL IS IN EFFECT UNTIL 10 AM TUESDAY ABOVE 4,000 FT. THE NORTH OREGON CASCADES, THE CASCADES OF MARION AND LINN COUNTY, AND THE CASCADES OF LANE COUNTY.
- A WINTER STORM WARNING IS IN EFFECT UNTIL 10 AM TUESDAY ABOVE 4,000 FT. FOR THE EAST SLOPES OF THE OREGON CASCADES.
- A WINTER STORM WARNING IS IN EFFECT UNTIL 10B AM TUESDAY ABOVE 4,000 FT. FOR THE OCHOCO AND THE JOHN DAY HIGHLANDS.
- A WIND ADVISORY IS IN EFFECT FROM 1 AM UNTIL 1 PM MONDAY FOR NORTHERN AND EASTERN KLAMATH COUNTY, AND WESTERN, CENTRAL, AND EASTERN LAKE COUNTY.
- A WIND ADVISORY IS IN EFFECT UNTIL 1 PM MONDAY FOR JACKSON COUNTY.
HEALTH ADVISORIES:
- A PERMANENT HEALTH ADVISORY REMAINS IN EFFECT FOR THE SOUTH UMPQUA RIVER BAR. POOLS IN THE BEDROCK ALONG THE RIVERS EDGE ARE KNOWN TO DEVELOP BLUE-GREEN ALGAE (CYANOBACTERIAL) BLOOMS THAT CAN BE HARMFUL TO PETS AND PEOPLE IF ACCIDENTAL INGESTION OCCURS. SIGNS HAVE BEEN POSTED ALONG SEVERAL ACCESS AREAS ALONG THE RIVER.
Forecast for the Southern and lower Mid Willamette Valley including Eugene-Springfield and Albany-Corvallis:
- Mostly cloudy with rain tonight (0.50 in. of rain possible).
- Mostly cloudy and slightly warmer with rain Monday (0.25 in. of rain possible), rain at night (0.25 in. of rain possible),
- Cloudy with AM rain likely (70%), a bit warmer with a good (50%) chance of rain Tuesday afternoon (0.25 in. of rain possible), a good (50%) chance of evening showers, rain likely (70%) late Tuesday night (under 0.10 in. of rain possible),
- Mostly cloudy with a slight (20%) chance of rain Wednesday, then a slight (20%) chance of rain at night.
- lows 42-47 cooling to 43 Wednesday night highs 52-55.
- Mostly cloudy and a bit cooler with a slight (20%) chance of rain Thursday, then cloudy with a slight (20%) chance of rain Thursday night,
- Mostly cloudy and a bit warmer with a slight (20%) chance of rain Friday, a (40%) chance of rain at night,
- Mostly cloudy and a bit cooler with rain likely (70%) Saturday, rain Saturday night,
- Then mostly cloudy and a bit cooler with showers Sunday.
- highs 53-54 cooling to 52 Sunday lows 43-45. (seasonal averages high 46 low 34)
Your College Football Weather Forecast:
Wednesday January 1, 2025:
The Ducks will play either #8 Ohio State or #9 Tennessee in the Rose Bowl, Pasadena, California: Game time to be announced. Way too soon for a preliminary weather forecast.
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HOME WOOD HEATING ADVISORY:
Eugene & Springfield: GREEN – The burning wood is allowed.
Oakridge and Westfir: GREEN – The burning wood is allowed.
The use of pellet stoves is always allowed.
Data courtesy of Lane Regional Air Protection Agency (LRAPA.org)
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Forecast for the Umpqua Valley including Roseburg:
- Mostly cloudy with rain tonight (0.25 in. of rain possible),
- Mostly cloudy with rain Monday (0.25 in. of rain possible), rain Monday night (0.10 in. of rain possible),
- Mostly cloudy with a good (50%) chance of rain and a bit warmer Tuesday (under 0.10 in. of rain possible), mostly cloudy with a (30%) chance of rain late at night (under 0.10 in. of rain possible),
- Mostly cloudy with AM rain, a good (50%) chance of rain and a bit cooler Wednesday afternoon, then a (20%) chance of rain Wednesday night.
- lows 42-46 cooling to 43 Wednesday night highs 50-56 cooling to 55 Wednesday .
- Mostly cloudy and a bit warmer with a slight (20%) chance of rain Thursday, mostly cloudy with a slight (20%) chance of rain Thursday night,
- Mostly cloudy with a slight (20%) chance of rain and a bit warmer Friday, a (40%) of rain late night,
- Mostly cloudy with rain and a bit cooler Saturday, rain Saturday night,
- Then mostly cloudy and a bit cooler with rain Sunday.
- highs 56-59 cooling to 54 Sunday lows 44-47. (seasonal averages high 48 low 37)
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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),
- Mostly cloudy with rain and a bit warmer Monday (0.25 in. of rain possible), rain Monday night (0.50 in. of rain possible),
- Mostly cloudy with a (40%) chance of rain and a bit warmer Tuesday (0.25 in. of rain possible), evening coastal rain likely (70%) with coastal rain late at night while inland rain likely (70%) Tuesday night (0.10 in. of rain possible),
- Mostly cloudy with AM rain, a good (50%) chance of rain Wednesday afternoon, then a (40%) of rain Wednesday night.
- lows 44-49 cooling to 47 Wednesday night highs 56-62.
- Mostly cloudy with a (30%) chance of rain Thursday, a (30%) chance of rain Thursday night,
- Mostly cloudy and a bit warmer with a (40%) chance of rain Friday and in the evening, rain late at night,
- Mostly cloudy and a bit cooler with rain Saturday, rain Saturday night,
- Then mostly cloudy with rain Sunday.
- highs 60-62 cooling to 55 Sunday lows near 49. (seasonal averages high 53 low 40)
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Forecast for the Northern Oregon Cascades including the Cascades in Lane County:
- Mostly cloudy with evening rain, snow likely (70%) with freezing rain, snow with a slight (20%) chance of freezing rain late tonight (0.75 in. of rain possible, 3-7 in. of snow possible, trace of ice accumulation possible),
- Mostly cloudy and a bit warmer with rain, snow and freezing rain Monday (0.50 in. of rain possible, 3-6 in. of snow possible, snow possibly heavy at times), a slight (20%) chance of evening freezing rain with rain and snow, rain and snow late at night (1.00 in. of rain possible, 5-11 in. of snow possible, a trace of ice accumulation possible, snow possibly heavy at times),
- Mostly cloudy with AM rain likely (70%) with snow (snow possibly heavy at times), a bit warmer with a (20%) chance of rain Tuesday afternoon, a (%) chance of evening rain, rain late Tuesday night,
- Mostly cloudy and a bit warmer with rain Wednesday, then mostly cloudy with a slight (20%) chance of rain Wednesday night.
- snow level 4,500 ft. tonight through Monday night, 5,500 ft. Tuesday, 6,500 ft. Tuesday night, then 7,000 ft. Wednesday and Wednesday night.
- lows 28-32 cooling to 30 Wednesday night highs 33-40.
- A mix of clouds and sun and a bit warmer with a slight (20%) chance of rain Thursday, mostly cloudy with a slight (20%) chance of rain Thursday night,
- Mostly cloudy with a slight (20%) chance of AM rain, partly cloudy with a slight (20%) chance of rain Friday afternoon, mostly cloudy with a good (50%) chance of rain at night,
- Mostly cloudy and a bit cooler with rain likely (70%) Saturday, rain and snow likely (70%) Saturday night,
- Then mostly cloudy and a bit cooler with a slight (20%) chance of snow showers Sunday.
- snow level 7,500 ft. Thursday through Friday, 7,000 ft. Friday night, 6,500 ft. Saturday, 6,000 ft. Saturday night, then 7,000 ft. Sunday.
- highs 42-37 lows near 32.