The dry weather and warming will continue in earnest through the workweek as strong ridge of high pressure intensifies over the Inland Northwest. For today, the models are in good agreement the center of the ridge will slide eastward and become stationary over southern British Columbia. This means most if not all valleys will see afternoon temperatures in the mid to upper 50’s under bright sunshine. Yesterday’s 52 degrees marked the first time the temperatures were above 50 degrees since early November of last year. The ridge is then expected to slowly move eastward taking up residence over western Montana. This will place Northcentral Washington under increasing south-southeast flow with continued warming.
On Tuesday, we can expect sunny skies with afternoon high temperatures in the upper 50’s.
Wednesday and Thursday will be the warmest weather days of the week with sunny skies each day and afternoon highs Wednesday in the upper 50’s and 60 degrees for our high by Thursday. These warming temperatures will continue to make a significant dent in the area snow pack. By mid-week, the snow pack across the Columbia Basin and Wenatchee Valley will likely be non-existent while we continue to slowly peck away at the deep snow pack elsewhere. Area streams and rivers won’t respond too much yet to the big warmup but some of the smaller rivers and creeks should begin to see rises over the next few days.
By Friday, the strong upper-level ridge will lose its grasp over the Northern Rockies and drift into the Great Plains as several pieces of weak energy approach from the Eastern Pacific. The main energy from these waves will be directed well south of the Inland Northwest continuing to deliver mild temperatures and dry weather. Afternoon highs look to remain in the 50s to low 60s on Friday with overnight lows in the upper 30’s to near 40 degrees overnight Friday. This will continue to enhance snowmelt but at slow rates given the lack of winds or precipitation.
For Friday night through Sunday, a slightly stronger shortwave passes through the area bringing the best chance for rain and high mountain snow. The Wenatchee Valley will see a 40% chance of rain overnight Friday. This will be a mild system with rain the dominant precipitation type for most locations of 5000-6000 feet and lower. We can expect mostly cloudy skies on Saturday and Sunday with a 20% chance of rain and cooler temperatures with highs both days in the lower 50’s. The combination of the incoming rain potential and mild temperatures will result in more snow melt/runoff which will contribute to ongoing field flooding and rises of streams and creeks.