The warm and sunny weather conditions we’ve recently experienced will begin to deteriorate today from west to east as a fairly potent weather system moves into the region. Precipitation is expected to begin along the Cascades late this morning and slowly move into the Columbia Basin this afternoon, then across Northcentral Washington tonight and Wednesday. The heaviest precipitation can be expected tonight and early Wednesday morning as the front moves through the Wenatchee Valley.
This weather system is very wet and will result in most locations receiving 12-18 hours of light to moderate rain. Precipitation amounts between a quarter and half of an inch will be likely with some areas in the Cascades looking at up to an inch. There is an 80% chance of rain in the Wenatchee Valley late today, a 90% chance tonight and a 40% chance of scattered showers on Wednesday. The large weather trough and upper level low will push south down the west coast and into California, which will bring us sunny skies on Thursday and partly cloudy skies Friday.
An easterly flow develops on Saturday, which could create more instability. We have a 40% chance of showers on Saturday and a 30% chance Saturday night. Late Sunday and into Monday, weather signs point to a decrease in the clouds and shower activity with hints of another high pressure ridge returning.