TONIGHT: We will see mostly cloudy skies with an 80% chance of winter mix in the valleys and moderate snow in the Cascades. Overnight lows will be in the low 30s and will be hit right at midnight as the storm system warm from will make the temperature rise instead of fall in the overnight hours. This will take the current freezing line at 500 ft up to 1,200 ft. Breezy winds out of the South at 10 to 15 and gusts up to 20 mph will keep wind chills in the 20s. We will see 1/10 to 1/3 of showers by dawn in the valleys.
TOMORROW: The first of two storm system will roll through the region in the morning with 80% chance of showers off and on through the morning with morning temperatures in the mid 30s with breezy winds out of Southwest at 5 to 10 and gusts up to 15 mph. As we move into the afternoon we will see a small break in the showers as we will be between storm system with mostly cloudy skies continuing and a 40% chance of light showers. AS we move into the evening the 2nd storm system will roll into the region and shower chances return to 80% with major snow for the Cascades.
EARLY NEXT WEEK: Fairly active pattern will continue through the long range. Operational 12Z GFS and ECMWF, when compared to the ensembles, are in fairly good agreement regarding the overall large-scale details. Another short-wave drops into the area from the northwest Mon night and Tue. This system will have a more maritime influence. Snow levels Mon night will generally be 1000 to 1500 feet, although down to 500 feet in the Gorge and East Skamania county. Model 1000-500 mb forecast thickness values will be in the 525-530 dm range with 850 mb temps around -5C. This system slides through the forecast area Tue. QPF amounts do not look all that impressive, but could be enough for snow advisory amounts in the S Washington and N Oregon Cascades. GFS 500 mb spaghetti plots start to show more variation beginning Wed. A deepening upper level trough along the British Columbia Coast will allow a more moderate west to northwest 500 mb flow to impact the area. A leading short-wave is expected to reach the area Wed night. The ECMWF indicates a complex surface low pressure off Vancouver Island 12Z Thu with an 8-10 mb KAST-KOTH south gradient. The operational 12Z GFS is much different, with a closed low off the Central Oregon coast and offshore low-level flow through the Gorge. The NCEP GFS ensembles valid 00Z Thu are all over the place, suggesting low confidence in the general forecast. Would tend to favor the ECMWF at this time and have trended the forecast in that direction. Eventually, the large upper level trough takes up residence over the NE Pac 00Z Fri. This would maintain an unseasonably cool air mass over the region, with snow levels generally 1000-1500 ft. There is better agreement between the GFS and ECMWF Thu night and Fri, leading to better forecast confidence. All in all, the extended period will continue the Cascade snowpack improvement, but not expecting any additional valley floor snowfall during the period.
Today's Record Temperatures