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) is sending moisture to the Pacific Northwest. The graphics for days 1-3 show a frontal system moving through the Pacific Northwest tonight and Saturday. The graphics for days 3-7 Tuesday through Saturday 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 WEATHER ADVISORY FOR FREEZING RAIN IS IN EFFECT UNTIL 2 AM TODAY FOR THE UPPER HOOD RIVER VALLEY.
- A WINTER WEATHER ADVISORY IS IN EFFECT FOR MODERATE TO HEAVY SNOW AND MIXED PRECIPITATION UNTIL 10 AM TODAY FOR THE EAST SLOPES OF THE OREGON CASCADES.
- A WINTER WEATHER ADVISORY IS IN EFFECT UNTIL 10 AM TODAY FOR MODERATE TO HEAVY SNOW AND MIXED PRECIPITATION FOR THE FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON AND NORTH CENTRAL OREGON.
- A WINTER WEATHER ADVISORY IS IN EFFECT UNTIL 7 AM SUNDAY ABOVE 4,500 FT. FOR THE NORTHERN BLUE MOUNTAINS OF OREGON AND THE NORTHWEST BLUE MOUNTAINS.
- A WIND ADVISORY IS IN EFFECT UNTIL 7 AM TODAY FOR NORTHERN AND EASTERN KLAMATH COUNTY AND WESTERN, CENTRAL AND EASTERN LAKE COUNTY.
- A WIND ADVISORY IS IN EFFECT UNTIL 10 AM TODAY FOR THE FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON
- A WIND ADVISORY IS IN EFFECT UNTIL 10 AM TODAY FOR THE GRANDE RONDE VALLEY.
- A COASTAL FLOOD ADVISORY IS IN EFFECT FROM 9 AM UNTIL 1 PM TODAY FOR THE CLATSUP COUNTY COAST AND THE TILLAMOOK COAST.
- A HIGH SURF ADVISORY IS IN EFFECT UNTIL 10 PM TONIGHT FOR THE SOUTH CENTRAL OREGON COAST.
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 and slightly warmer with showers and a slight (20%) chance of thunderstorms this afternoon and evening (0.25 in. of rain possible), showers likely (70%) late tonight (under 0.10 in. of rain possible),
- Some possible AM clouds and sun with a slight (20%) chance of showers, mostly cloudy with a slight (20%) chance of showers Sunday afternoon (under 0.10 in. of rain possible), rain at night (0.10 in. of rain possible).
- Mostly cloudy with rain Monday, then rain Monday night.
- highs near 49 lows 37-42.
- Mostly cloudy and a bit warmer with a (40%) chance of showers Tuesday, a slight (20%) chance of showers Tuesday night,
- Mostly cloudy and a bit cooler with a slight (20%) chance of showers Wednesday, mostly cloudy at night,
- Mostly cloudy and a bit cooler Thursday and Thursday night,
- Then mostly cloudy and a bit warmer Friday.
- highs 53-48 warming to 50 Friday lows 40-36. (seasonal averages high 47 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 a good (50%) chance of AM showers and a slight (20%) chance of thunderstorms, a bit cooler with showers (0.50 in. of rain possible) and a slight (20%) chance of thunderstorms this afternoon, evening rain showers with snow showers likely (70%), rain and snow showers late tonight (0.10 in. of rain possible),
- Partly cloudy with patchy AM fog with a slight (20%) chance of AM showers, mostly cloudy a bit cooler with a slight (20%) chance of showers Sunday afternoon (0.10 in. of rain possible), cloudy a good (50%) chance of evening showers, showers late Sunday night (0.25 in. of rain possible, snow level 3,500 ft.),
- Mostly cloudy with showers Monday and in the evening, then a good (50%) chance of rain late Monday night.
- highs 48-50 lows 37-42.
- Mostly cloudy with a slight (20%) chance of AM showers, just mostly cloudy and a bit warmer Tuesday afternoon,mostly cloudy with patchy evening fog, areas of fog last Tuesday night,
- Areas of AM fog, mostly cloudy with slight (20%) chance of rain Wednesday, mostly cloudy with patchy fog at night,
- Partly cloudy and a bit warmer Thursday and in the evening, mostly cloudy with a slight (20%) chance of showers late Thursday night,
- Patchy AM fog then mostly cloudy with a (30%) chance of showers Friday.
- highs 53-56 lows near 40. (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 a (30%) chance of AM showers and a slight (20%) chance of thunderstorms, a bit cooler with showers likely (70%) and a slight (20%) chance of thunderstorms this afternoon (0.10 in. of rain possible), evening showers with a slight (20%) chance of thunderstorms, showers with patchy fog late tonight (0.10 in. of rain possible),
- Some AM clouds with patchy fog, mostly cloudy and a bit cooler with a (30%) chance of coastal showers while a slight (20%) chance of inland showers and a bit warmer Sunday afternoon, cloudy with a good (50%) chance of evening showers, then showers late at night (0.25 in. of rain possible).
- Mostly cloudy with showers and a bit warmer Monday and in the evening, a good (50%) chance of showers late Monday night.
- highs 54-56 lows 38-44.
- Mostly cloudy and a bit warmer with a (30%) chance of showers Tuesday, a slight (20%) chance of showers Tuesday night,
- Mostly cloudy with a slight (20%) chance of showers and a bit warmer Wednesday and in the evening, patchy fog late at night,
- Partly cloudy and a bit warmer Thursday, mostly cloudy with a slight (20%) chance of showers Thursday night,
- Mostly cloudy with a (40%) chance of AM showers, then showers likely (70%) Friday afternoon.
- highs 60-63 lows 42-40 warming back to 42 Thursday night. (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 AM rain showers and snow showers with a slight (20%) chance of AM freezing rain, snow showers and freezing rain this afternoon, snow and rain showers tonight,
- A mix of clouds and sun with a good (50%) chance of AM snow showers, a slight (20%) chance of rain and snow showers Sunday afternoon, snow and rain likely (70%) at night,
- Mostly cloudy with rain and snow Monday, then rain and snow likely (70%) Monday night.
- snow level 3,500 ft. today, 2,500 ft. tonight and Sunday, 3,500 ft. Sunday night, then 4,000 ft Monday and Monday night.
- highs near 32 lows 22-29.
- A mix of clouds and sun and a bit warmer with a good (50%) chance of rain and snow showers Tuesday, mostly cloudy with a slight (20%) chance of rain and snow showers Tuesday night,
- A mix of clouds and sun and a bit warmer with a slight (20%) chance of rain and snow showers Wednesday, just mostly cloudy at night,
- Then mostly sunny and a bit warmer Thursday, partly cloudy Thursday night,
- Then partly cloudy Friday.
- snow level 4,500 ft. Tuesday, 5,500 ft. Tuesday night, 6,500 ft. Wednesday, free air freezing level 11,000 ft. Wednesday night and Thursday, then 12,000 ft. Friday.
- highs 37-42 lows 27-29.