Another Record Bites The Dust

SEATTLE - It was already bright out there today, but those who noticed a white hazy-glow around the Seattle Center area today, that was just me wearing shorts for the first time in 10 months. Yes, it was that hot out there Monday.

Temperatures were well into the 80s and, in many cases, the 90s around the Puget Sound area again Monday afternoon. For the second straight day, Seattle broke their record high -- this time we hit 90, breaking the old record of 88.

Here's an unofficial list of high temperatures around the area for Monday as of 5 p.m.:

Shelton: 95
Olympia: 93
Bremerton: 90
Seattle: 90
Forks: 90
Renton: 89
Tacoma: 88
Port Angeles: 86
Friday Harbor: 84
Everett: 83
Bellingham: 80

And it was triple digit weather again to our south, with Portland hitting 102 and Vancouver, Wash. hitting 101.

Why Is It So Hot?

During a usual Seattle summer day, we have our "natural air conditioning" in the form of a westerly wind that blows in off the Pacific Ocean. That keeps temperatures in the 70s.

However, Sunday and Monday, we have a strong thermal trough building into the area (read more about thermal troughs in our Weather FAQ) helping to pull our winds from the east instead of the usual west.

When winds come from the east (an "offshore" wind) that does a few things:

1) That air is coming from a much hotter Eastern Washington, so it's already got a head start in being warm.

2) As that air comes over the top and sinks down the Cascade mountains, it heats up even more (as air warms and dries out when it sinks, just like it cools and becomes more moist as it rises.) Forks on the coast also usually gets abnormally hot in this pattern as air sinks down the western slopes of the Olympic Mountains. That's how they hit 92 Sunday.

and 3) It holds back the west wind from coming in off the ocean to cool us off.

Add that all up, and we're looking at afternoon and evening temperatures around the Puget Sound area in the upper 80s and 90s.

More 90-Degree Weather Stats

Just in time for the heat wave, the National Weather Service compiled some interesting statistics you might find amusing:

Seattle hitting 90 Monday is the first time since August 2004 that it's been 90 or better. The most times its hit 90 or better in a year was 9 times, set in 1958.

There have been 14 summers since 1950 where it did not hit 90 (including, obviously, 2005, plus there was a three-year stretch in the late 90s where we didn't get to 90.)

The 1970s had 35 days of 90 or hotter, while the 1960s, 1980s and 1990s had 30. The 1950s had 18. Counting Monday, the 2000's so far have had 10.

The all-time record high temperature for Seattle is 100, set July 20, 1994. It hit 94 on the next two days, then didn't hit 90 the rest of the summer.

Still Sunny, But A Touch Cooler Tuesday

While continuing sunshine makes the forecast pretty easy, there are still some temperature forecasting challenges ahead.

The forecasting models are pretty adamant about cooling us off some to the low-mid 80s for Tuesday as a trickle of marine air moves in. But it seems like it won't be much help -- at least for Monday. The coast was still baking today (Forks was nearing 90 before cooling off a bit in the evening) and typically they should be plunging back to the 60s by now if we were to start to really cool off the next day -- although Hoquiam did go from 82 to 69 within an hour as a seabreeze picked up but the rest of the coast was still pretty hot.

So I think Tuesday will be another hot day in the general Puget Sound area. We're going to go with 85 for Seattle, and near 90 along the foothills and south of Tacoma, but I could see it getting warmer, so we'll cross our fingers for cooler, but keep your heat preparations going for another day. The coast should begin to cool down from the south as Tuesday progresses, so it might warm up a little in the morning but then level off and even cool off sharply as you get into the afternoon.

A cooler coast Tuesday would then make for stronger signs that we'll cool down more significantly for Wednesday in the inland areas. There might even be brief morning clouds, but still plenty of sun and highs in the upper 70s.

The rest of the week shows weak onshore flow but a warm air mass keeping temperatures above normal amid plenty of sunshine. We'll peg highs in the upper 70s to low 80s, with the warmer days leaning toward Friday and Saturday and perhaps a bit more cooling for Sunday and Monday.

Cool enough to where I'll spare the locals the glare and switch back to pants :)