The jet stream shows a high pressure ridge (“arch” shape) moving away from us as a low pressure trough (“U” shape) dropping in behind it. A frontal system is going to bring the Pacific Northwest rain, dropping, temperatures, and more mountain snow.

_______________

Advisories:   A WINTER STORM WATCH IS IN EFFECT FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING ABOVE 4,000 FT. FOR THE NORTH OREGON CASCADES, NOT INCLUDING THE CASCADES OF LANE COUNTY.

________________

Here are your detailed forecasts. **

_________________

Forecast for the Southern and lower Mid Willamette Valley including Eugene-Springfield and Albany-Corvallis: Cloudy  tonight with a slight (20%) chance of rain late, a good (50%) chance of AM rain, rain Monday afternoon (0.25 in. of rain possible), rain Monday night (0.75 in. of rain possible), showers likely (60%) Tuesday AM, and a good (50%) chance of showers Tuesday afternoon and evening (0.10 in. of rain possible), mostly cloudy with showers likely (60%) late Tuesday night (0.25 in. of rain possible), showers Wednesday and Wednesday night lows 42-36 highs 58-44. Partly cloudy with a good (50%) chance of showers Thursday, mostly cloudy with a (30%) chance of showers Thursday night, partly cloudy with a slight (20%) chance of showers Friday, mostly cloudy with a slight (20%) chance of showers Friday night, then just mostly cloudy Saturday through Sunday with a slight (20%) chance of showers Sunday highs 48-58 lows 37-42. (seasonal  averages high 59 low 38)

_______________

Forecast for the Umpqua Basin including, Roseburg: Mostly cloudy tonight, cloudy with a good (50%) chance of rain Monday, rain Monday night, rain likely (60%) Tuesday AM, a good (50%) chance of afternoon showers (snow level 3,000 ft. falling to 2,500 ft. in the afternoon), a (40%) chance of rain and snow showers Tuesday night, then rain and snow Wednesday and Wednesday night lows 38-46 cooling to near 37 Tuesday night and Wednesday night highs 63-47. Mostly cloudy with rain and showers likely (60%) Thursday, a (30%) chance of showers Thursday night, then mostly cloudy with a slight (20%) chance of showers Friday through Sunday highs 50-62 lows 34-40. (seasonal averages high 63 low 39)

_______________

Forecast for the South Oregon Coast including Coos Bay and North Bend: Mostly cloudy tonight with a slight (20%) chance of  coastal rain, a slight (20%) chance of rain inland late tonight, cloudy with a (40%) chance of AM coastal rain Monday and rain likely (60%) in the afternoon, a good (50%) chance of rain inland, rain Monday night, rain likely (60%) Tuesday AM,  a good (50%) chance of showers in the afternoon, showers likely (60%) Tuesday night, then rain Wednesday and Wednesday night lows 40-46 cooling to 38 by Wednesday night highs 54-46.  Mostly cloudy with a good (50%) chance of showers Thursday, a (40%) chance of showers Thursday night, then mostly cloudy with a slight (20%) chance of showers Friday night through Saturday night, then a (30%) chance of showers Sunday highs 50-58 lows 37-44. (seasonal averages high 56 low 42).

_________________

Forecast for the Cascades of Lane County: Mostly cloudy with a slight (20%) chance of snow late tonight, cloudy with a (40%) chance of rain and snow Monday AM, rain and snow likely (60%) Monday afternoon (5-9 in. of snow possible), rain and snow Monday night (12-18 in. of snow possible), rain and snow showers likely (60%) Tuesday (1-3 in. of snow possible), a good (50%) chance of snow showers Tuesday night, then snow showers Wednesday and Wednesday night snow level 3,000 ft. tonight, 4,500 ft. Monday and Monday night, 3,000 ft. Tuesday, 2,500 ft. Tuesday night, and at the surface Wednesday and Wednesday night lows 25-30 falling to 25 by Wednesday night highs 45-30. Mostly cloudy with a good (50%) chance of snow showers Thursday and Thursday night, a (30%) chance of rain and snow showers Friday and Friday night, a slight (20%) chance of snow showers Saturday, a slight (20%) chance of rain and snow showers Saturday night, then just mostly cloudy Sunday snow level at the surface Thursday, 2,500 ft. Thursday night, 3,500 ft. Friday and Friday night, 3,000 ft. Saturday and Saturday night, then a free air freezing level rising to 5,500 ft. Sunday highs 34-36 lows 27-24.

_________________

**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.