High pressure will be over the inland northwest today for warm and dry weather conditions. Under sunny skies, temperatures will continue to be above normal with highs today in the mid-40s. Another beauty of a day is expected Friday with temperatures just slightly cooler than today into the lower and mid 40’s.
The large ridge of high pressure will continue to flatten Friday night and Saturday as another upper low tracks through northern British Columbia. The low will drag a warm front through Northcentral Washington with a chance for light precipitation for the Cascade crest by Saturday afternoon. The Wenatchee Valley will see mostly cloudy skies throughout the day on Saturday with a 30% chance for late night rain showers turning to light snow overnight into Sunday morning. Precipitation will be light with generally under 0.05 of an inch possible. Snow levels around 4500 feet will give a chance for snow down to about Stevens Pass but accumulations will be light and generally under a half inch.
There is a 20% chance for a rain mixed with snow shower Sunday morning with mostly sunny skies by afternoon with high temperatures in the mid to upper 40’s. Winds will become breezy from the west Sunday afternoon from the Wenatchee River Valley to the Palouse. Wind speeds Sunday afternoon will increase toward 10-15 mph with gusts around 25-30 mph. Overall, weather models are in decent agreement regarding the quick hitting, and generally light precipitation event this weekend.
That all changes next week as we see a major shift in the weather pattern for the upcoming holiday week. Confidence continues to increase for a deep trough of low pressure to carve out much of the Western United States and allow cooler, Canadian air to infiltrate the Inland Northwest. In addition to the cold, several pieces of energy dropping into the trough will bring a chance for precipitation.
Increasing clouds on Monday ahead of the weather system with a 20% chance for rain mixed with snow by Monday night, highs in the lower 40’s. At this time, snow amounts remain very uncertain with the range for most lowland locations ranging from 0 to 8 inches over the multi-day period. So given this uncertainty, it would be best at this time to start preparing for potential snow and consider what might be the best travel days to reach your destination safely. From what we are seeing in the weather models today, looks like Monday will mainly feature snow showers for the passes and the potential for more widespread light to moderate snows could arrive roughly in the Tuesday-Thursday time-frame. These details will become sorted out in the coming days.
As for temperatures, look for high temperatures to begin to crash Monday and continue well into the end of the week. Afternoon highs start off in the 40s and upper 30s Monday then struggle to make it out of the low to mid 30s by Thursday. Overnight lows will be dip into the 20s early in the week then teens by the end of the week.