In what ways is the Kitsap Peninsula affected by these heatwaves?

It seems like yesterday we were having this discussion about heatwaves and thermal troughs in Western Washington. It wouldn’t be a bad idea to refer you to Scott Sistek’s article on thermal troughs and get acquainted with the kind of weather pattern we’ll be experiencing within the next couple days.

As a side note, yesterday’s forecast temperature was admittedly a disaster, with a forecast of 79 and an actual high temperature of 88! It’s a daily struggle to find the right temperature for every day of the week. Sometimes you win the lottery, other times you don’t. I think that’s one of the reasons I’m so drawn to forecasting weather in this part of the world. As hard as it is, it definitely has its rewards. Not every heatwave, snowstorm, windstorm or arctic blast materializes exactly as expected, but the goal is to get as close as possible, and when it happens it’s the best feeling ever!

On the Kitsap Peninsula, there are a lot of factors that make our weather so unique (and challenging to forecast!) and one of those things is: offshore flow. We’ll have a discussion on winter time offshore flow in a few months, but for now we’ll focus on the summer east wind. As the oven door flies open and the hot desert air spills over the Cascade mountains, the foothills of Western Washington is the first to bake. This hot air then rapidly slides down the mountain and envelops the Seattle area, which in turn races across the Puget Sound, smothers the Kitsap Peninsula and then a part of that flow hits a barrier.

The Olympic Mountains serve as a barrier between us and the Pacific Ocean. Usually when cold air spills over from Eastern Washington, it settles in a “bowl” on the peninsula due to its high density and sinks. On the other hand, hot air usually just continues to circulate, leaving room for slightly warmer daytime temperatures on this side compared to Seattle (some examples include the July 2009 and early August 2012 heatwaves where Seattle started warmer at first due to offshore flow, but we ended warmer). And when you add a thermally induced trough of low pressure to the mix, which will be the case this time around, it gets even hotter. The reverse is often true for cold weather. But it’s a lot easier to scour out hot weather on the peninsula than it is cold weather, mainly because heat is less dense.

So there’s a little info on heatwaves and how the Kitsap Peninsula is affected during such events. And wouldn’t you know it, we’ll get to apply this principle a little bit this week! Tuesday will feature some morning clouds, thinning out to just high clouds and temperatures a few degrees cooler in the upper 70s to low 80s.

Offshore flow kicks in Tuesday night and you’ll notice Wednesday will feel a lot like today as highs will reach the mid and upper 80s.

Then we bake. Thursday and Friday will feature clear blue skies and hot temperatures in the low and mid 90s. We could break some more records this time around…we’ll see how likely it is to break them a little later on this week.

The weekend will be a bit of a wildcard as a tropical-like upper level trough will swing through the area, developing the risk for showers and thundershowers Saturday evening through Sunday. Keep your eyes peeled and your cameras charged! 🙂

And then next week will be the same old, same old as morning clouds and afternoon sun once again enter the picture to cool things off.

Don’t you love our wonderful natural air conditioning?

Matthew Leach

Forecasting Kitsap

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