Thunderstorms

We have some potentially interesting weather coming up. But not tomorrow. Saturday will be beautiful...warm (into the lower 80s over much of the lowlands) and dry away from the mountains. Up in the Cascades there is a slight chance of some convective showers. But nothing serious.
And then there is Sunday. The air over us will be unstable, which means a little lift can release convection (i.e., thunderstorms). A measure that meteorologists look at to determine the potential for thunderstorms is CAPE--Convective Available Potential Energy. Sound impressive. Anyway, the values on Sunday will be high..particularly over the mountains (I have included a graphic of it that you can use to impress your friends). Normally we don't see CAPE of more than a few hundred here. But the CAPE tomorrow afternoon approaches 2000 over the northern Cascades, and over a thousand above all terrain. Something major is going to happen. In addition, an upper trough (which provides lift to release the instability) will move through on Sunday (see graphic). Between them, there is good chance of showers and thunderstorms over the mountains during the day and eastern Washington at night (see graphic of precipitation). Even a chance the lowlands could catch some of the action. Now a big worry is lightning caused fires...so we will have to watch this.

But wait! There's more! The trough will help incite an onshore push, which will bring cooler marine air into the region starting Sunday afternoon.

So enjoy a picnic tomorrow and enjoy the weather action on Sunday..particularly later in the day.

Also, If any of you are interested I will be giving a oublic talk in Leavenworth at 7 PM on July 31st and a book signing at 1 PM on August 1 (see more info to the right).