Friday, June 12, 2015
Though it looks like our past few days of very wet weather will change today, we will still be susceptible to the typical summer afternoon thunderstorms through the next week. Storms may be limited today by the cool air left behind by the departing storm yesterday, but I would expect Saturday to have a good chance of afternoon storms.
Some dry air does sneak in here Sunday for a a downturn in the afternoon storm chances, but a wave traveling north of us along the Canadian border will allow some cool air to infiltrate the region on Monday and destabilize the atmosphere. This, along with additional ill-defined waves for Tuesday and Wednesday will delay the strong drying advertised in the last forecast and lead to a good chance of afternoon storms for each of those days.
The dry air is now timed to arrive around Thursday and last into at least part of the following weekend, limiting or even eliminating the chance of the summer afternoon thunderstorm. There is model disagreement near the middle of that weekend as forecasts are at odds with the degree of interaction between a Pacific wave entering the northwest coast and cool air over the Canadian plains, leading to an uncertain forecast for then.