Turning Up The Heat Again!

I spent a long time trying to write a creative first sentence for this post. I was trying to make a joke comparing thermal troughs to stock market bubbles, as they bear (no pun intended) some similarities. After all, once a thermal trough has passed to our east, temperatures crash, just like the market corrects itself after a period of delirious bullishness. Last week featured a particularly drastic crash, although unlike the dot-com bubble of 2000, it was welcomed by the vast majority of citizens.

However, it looks like we’ll see another surge in temperatures this week. Let’s take a look at some insider information to get a better idea of what’s in store for the next couple days.

Here’s one of my favorite charts from the University of Washington’s WRF-GFS model: the 1000-500 mb (millibar) thickness with sea-level-pressure in hPa (hectopascals). Hectopascals and millibars are equivalent, so I’m not sure why this chart has both instead of choosing one or the other. Variety is the spice of life, I guess!

As you can see, the upper-level trough that brought us cooler temperatures today is moving to the east, and another ridge of high pressure is building off our coast. This ridge will strengthen and retrograde westward as the week goes on.

Additionally, a thermal trough will extend northward into our area from California. Look at the temperatures at the 850 mb level (around 5000 feet) of the atmosphere at 2 am Thursday below, and notice the tongue of warm air over the Central Valley extending northward along the coast. That’s our thermal trough!

This thermal trough is weaker than the one we saw last week, and as a result, offshore flow will not be as strong and high temperatures will be cooler. Still, expect highs to approach 90 degrees for many locations throughout Western Washington on Thursday and Friday.

On Saturday, flow switches from offshore to onshore, and temperatures plunge back into the 70s. It will look almost exactly like what we saw this past Sunday.

After onshore flow returns, we look to settle into a more seasonable pattern, with temperatures near or just below average and a few showers at times. A change is nice, but I will miss the heat too.

Thanks for reading!

Charlie