Weather Blog

Notes and scribbles from this past week's sorta-heat wave

Notes and scribbles from this past week's sorta-heat wave

It was the longest stretch of 80 degree plus weather that Seattle has ever seen in September, but aside from that, the heat wave was more bark than bite. But I figure I'd catch up on a few notable items from the nine days of sun fans' bliss.

It was record-breaking! Well, technically

In case you missed it, Seattle did officially set a record with the warm stretch -- nine days in a row of 80 degrees or warmer in September from the 3rd to the 11th. The old record was eight set in 1989. Had Monday managed to reach 80, a 10-day streak would have tied for third longest in any month. But the stubborn morning clouds have officially given the fatal blow to the 80s streak.

Aside from that, Seattle tied the record high of 85 on Friday, but surprisingly both weekend heat records survived. And we tied a record for most consecutive days at 85 or warmer in Seattle at two. But! We were a degree away from shattering that -- Saturday only topped out at 84 or else we'd have had a four-day streak.

Could it have been the most consistent weather in Seattle history?

Another remarkable feat of the warm stretch was how amazingly consistent each day was -- only a 3 degree spread in high temperatures from Sept. 3 to Sept. 11.

Here is how the climate sheet reads: 82, 83, 82, 84, 83, 85, 85, 84, 85. I don't think I can ever recall a stretch in Seattle where the temperature was within 3 degrees for over a week -- especially one that was a solid 8-10 degrees above normal with blazing sunshine. (And each day did count as an official sunny day. Nine of 11 days in September were sunny - amazing when you consider where we were this spring.)

We were lucky in that we had a nice ridge of high pressure to keep the clouds away and draw up a little warm air from the south. However, the east wind never really materialized until Saturday into Sunday to hold back the sea breezes, and even then it was pretty weak. Usually a heat wave is its own demise as when the east winds finally subside, the west wind takes over with a vengeance giving us... well, the cloudy weather we're seeing Monday. Instead, with a weak marine flow and a strong ridge entrenched, the pattern was able to run for a while.

When the bough breaks...

Is it me? Or is this limb getting wobbly?

While I'm sure many people were happy that the highs over the weekend were in the mid 80s, instead of 90-something, I know we were forecasting higher temperatures -- we had upper 80s on Saturday and even trotted out the 90 on Sunday. And we're aware that we were going warmer than just about any other forecast out there. We crawled out onto the 90 limb on the belief that a building thermal trough would kick up the east winds more than was being advertised. And we figured that since we were in the mid 80s without the wind, we'd easily go warmer with the wind.

But we fought the calendar and the calendar won. There is a reason it has only hit 90 10 times in Seattle since Sea-Tac Airport opened in 1945 -- it's really hard to get that hot this late in the season, especially when you've got 2 1/2 hours less daylight to work with. But 90s have happened in September -- we've even had a 2-day 90 stretch in 1967 and that was even later in the year! (Sept. 14-15). So it was not unheard of, and this to us looked like a prime set up to get there.

Alas, while the lowlands had some localized east wind, the thermal trough was not strong enough to draw the east wind over the Cascades -- the pressure in Seattle never made it lower than Wenathcee to draw the wind over to this side of the hills -- and we lost that critical warming aspect. So we climbed out on the limb, and... you know the rest of the story. Hopefully it didn't mess up any plans.

(Also, while we're in "mea culpa" mode -- if you read my forecast discussion Friday, I mentioned that the record high for Sunday was 83, but it turns out it was 87 -- I have a printed list that goes through 2005, but missed scribbling in my notes that we broke that record in 2009. Oh, and I also forgot the dryer sheet when putting a load of my kids' laundry in the dryer this weekend, so they could be suffering from acute static cling this week.)

Party like it's 1989?

The streak of 80s we just topped from 1989 was remarkably similar to our own -- only its streak ranged from 80 to 85. That year, the weather cooled off for a week-- but summer took a parting shot with another 4-day 80 streak that even saw the temperature zoom to 91 degrees on Sept. 22 -- setting the record for latest 90 degree day on record. (That record was matched the following year.)

This year, long range models have been toying with another punch of warm air sometime after next weekend -- it's really varied in strength from sizzle to 'meh'. But if the sizzle comes to fruition, you'll know it's happened before.

(Only this time we might be a little less apt to forecast 90...)

It made for some pretty sunsets and sunrises

Sunshine in Seattle does make for some gorgeous sunsets and sunrises. Take a peek at a few from this week:


Sunrise by YouNews contributor aronoiiel in East Tacoma:

Sunrise by YouNews contributor dontography in Kent:

 And ever wondered what happens at night? Check out this time lapse video of Saturday night from Greg Johnson near Hansville: