A Cool/Wet Start of Summer

The forecasts for the next week or so are definitive:   we are going to start the summer quite cool and wet.

And the implications for both wildfires, water resources, and agriculture are quite positive.

Let me begin with temperature, showing you the temperature anomalies from normal for the next 15 days from the most skillful system in the world (the AI forecast of the European Center). 

Blue indicates below normal (up to 5 F colder than normal), and green indicates even colder anomalies.

For the next five days, the whole region is cold, with some areas of Oregon over 10F colder than normal.  

The following five days (through July 2) are colder than normal over the entire region, with British Columbia being the most frigid.

Even colder for the following five days (through July 7).

In Seattle, my colleagues at the National Weather Service don't predict high temperatures will reach 70F during the next week (below).

Importantly, no big heatwave in eastern Washington, so crops will not be stressed.  To show this, here are the predicted temperatures at Yakima.  Very temperate for the dry side.

And there will be precipitation at times through July 8. 

Substantial amounts in the Cascades (up to around 2-3 inches) and large totals in the Rockies (see below).  Importantly, even eastern Washington will get some light rain.

Want more good news?     

This kind of cool pattern is very favorable for wind energy, as it is associated with substantial westerly winds descending the eastern slopes of the Cascades.   To demonstrate this, below are the latest wind generation numbers from Bonneville (below)

Wind energy generation (the green line) surged upwards as temperatures cooled.  Furthermore, energy use (red line) has dropped substantially as air conditioning demands have declined with the cooler temperatures.

Can you imagine what the Seattle Times Climate Lab and some amateur online sites would be saying if there were a warm anomaly of the same magnitude as the upcoming cold period?  They would be making all kinds of claims about global warming.  

And no....this is not evidence of global cooling. 😕

Thunderstorms and a Winter-Like System Approaches the Pacific Northwest

A wet, winter-like frontal system is now approaching the Northwest and will arrive on Friday, but before I discuss it, let's consider the substantial thunderstorm activity that struck the regional mountains on Wednesday.

The weather radar image around 2 PM Wednesday showed a strong thunderstorm over the northeast Olympics and a line of convective showers over the eastern slopes of the Cascades.

The Seattle Space Needle panocam showed the extensive scale of the Olympic Peninsula thunderstorm:

And the Space Needle cam also indicated a line of storms over and east of the Cascades.

The Wednesday thunderstorms were associated with hundreds of lightning strokes, as illustrated by a one-hour sample during the mid-afternoon on Wednesday:

Why is there so much lighting on Wednesday afternoon?    

The air above us was unusually unstable, meaning that a rising parcel of air would tend to accelerate upward if lifted.   A measure of such potential instability is called CAPE (Convective Available Potential Energy), and values of CAPE were unusually high over the region (see plot below).

High for the Northwest, but the folks in the Midwest would laugh.

Convection tends to release at the surface warms, but yesterday the process was aided by increasing westerly winds (from the west), which provided strong upslope flow over the high terrain.  It helps to give the air a kick upwards to get the instability going.

Finally, a wet, winter-like system is now approaching our region, as illustrated by the latest infrared satellite image (below).  Looks like winter!

The total forecast precipitation over the region through Sunday morning is substantial (see below), and should both moisten the surface, add to the water supply, and reduce wildfire potential.