The Puget Sound area is sizzling under one more hot day Friday, but it'll be the final day of this three-day heat wave and I think the payoff this weekend might have made it worth it as we are expecting more pleasant temperatures.
But in the short term, it's another scorcher, just not as scorching as Thursday. Temperatures will be around 5-7 degrees cooler Friday, but that still means highs near 90.
Seattle's forecasted high is 89 degrees which would be two degrees short of the record of 91, but 91 is not out of the realm of the possible. The air mass also is not going to be as dry Friday as it was Thursday so it might feel warmer with the slightly higher humidity.
Out on the coast, it's a different story and a different world. Low clouds and fog are perched along the shorelines, awaiting their marching orders to come inland. But as they sit over there, it means a mostly cloudy day on the coast with highs in the 60s to low 70s.
What's The Deal?
The intense heat from Thursday was aided by a thermal trough which draws in a hot, dry wind from Eastern Washington. As an added bonus, that air heats and dries out even more as it sinks down the western slopes of the Cascade and Olympic Mountains (why the coast was so hot on Wednesday.)
That thermal trough is now in Eastern Washington, meaning we've now lost the east wind component to the heat wave that was cooking us toward medium well. However, we haven't really got that punch of cooling marine winds yet to cool us off either (just a light trickle of west wind so far), so with the lingering hot air mass, we are still expecting a toasty day.
Put another way, think of a stove that's turned on high. When you turn the burner off, it still stays hot for a while, and that's the deal with our air mass -- still hot from Thursday even though the "burner" is off, but not quite as hot and thus the slightly cooler day today.
On the other hand, that lack of east wind is coming with a price. Since we don't have that sinking air to dry us out and the air flow has switched to a trickle of marine flow, the humidity is higher, so it'll be a touch muggier today.
A slightly better punch of marine air is expected to come in Friday night, and that might even be strong enough to briefly bring some morning clouds to the area Saturday morning, but they won't last long and we'll quickly get to a sunny day. The mix of a little more marine air-but-not-big-punch-of-marine-air will have to counter-balance the still-hot air mass so we think that'll balance out to a high of around 78-80.
A stronger marine push is out there somewhere, poised to strike either Sunday or early next week. Forecasting models are starting to hint at a bigger marine push for Saturday night into Sunday. If so, Sunday might end up having to wait until afternoon for the sunshine to break out and might be closer to 72, but others still think we're close to 80.
If you want to think of this as Mother Nature waiting to sneeze in the marine clouds from the coast, Saturday and Sunday, we're in the "Ah... ahh..." part before the "Achoo!" that comes either Sunday or Monday morning and brings in a solid layer of marine clouds. (Or, feel free to come up with your own less-third-grade-like analogy. It's Friday and the coffee still hasn't kicked in yet.)
Suffice to say, it'll be cooler next week with temperatures in the more manageable 70s, with varying amounts of morning (and afternoon) clouds burning away to sunshine.
And for sun fans, at least it's not back into the cooler!
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