Updated Thursday 3:20 p.m.
Have you in Seattle received any calls from friends on the ocean beaches bragging about how it's so much nicer over there today? (They're probably getting in their ribbing while they still can.) Not that sunny and mid 70s that we have in Seattle today is bad, but the coast has been pushing 80 today.
That's due to a thermal trough that didn't quite make it all the way north into our area today -- looks like it made it to about a line between Hoquiam and somewhere between Kelso and Vancouver, but it's a fascinating snapshot into just how thermal troughs affect our weather. Down south where you've got the hot, east wind, it's a marginal heat wave -- Portland and northern Oregon was well into the 80s and likely going to push 90. Hoquiam was 79 at 3 p.m. while Astoria was 81.
But Kelso, with more of a northerly wind -- they're likely north of the thermal trough's boundary -- was at 79 this afternoon, 8 degrees cooler than just down I-5 in Vancouver where it was 87. In Seattle, a due north wind has kept it in the mid-upper 70s, and Everett had yet to break 70 (67 degrees at 3 p.m.)
We've got another gorgeous day on tap, but with some tweaks. First of all, the thermal trough will probably budge a little north and east Friday morning, warming us up quickly, but then shifting farther east into the mountains later in the day, switching us to a cooler west wind.
So for Seattle Metro area, expect sunny skies, a quick warm up -- probably topping out in the upper 70s/near 80 by mid to late afternoon, and then a cooling seabreeze in the evening and fairly rapid cool off after sunset. (If you're going to any of the late Bumbershoot festivities, bring a light jacket even if it's 80 when you leave.) On the coast, the west winds will be there from the start and you are looking at a more typical cloudy and cool day with highs in the 60s. North Sound should be pleasant and about on par with today -- maybe 1-2 degrees warmer, then the stiff seabreeze late.
While September 3rd is too early to call summer over, it sure might feel like it as the weather rapidly changes Friday night and we switch to a much cooler and cloudier pattern for the Labor Day Weekend. In fact, forecast models continue to trend a bit more pessimistic with each run. I think most area have a decent chance of showers now on Saturday as the first of two low pressure troughs move through - although still not looking like a washout, but certainly some periods of rain. One area to watch is the Convergence Zone area between North Seattle and Everett as the models seem to want to form another one in the trough's wake. Typically these would be north of Seattle Center, but PSCZ's can stretch south into Downtown Seattle so plan for rain and hope for the best. Highs Saturday will only be in the mid 60s.
Sunday is looking like the best of the three days, but still mostly cloudy and still a risk of showers -- just a smaller risk than Saturday and Monday and perhaps some sunbreaks with highs in the low-mid 60s.
Another trough drags through on Monday into Tuesday, with likely yet another Convergence Zone forming (Sorry Everett and Shoreline and spots in between -- this is probably going to be a fairly soggy weekend for you) so expect generally scattered showers across the region, with extra emphasis in the Convergence Zone. Highs will stay in the low-mid 60s.
We do start to rebound a bit for the middle of next week, but not as much of a rebound as this week. Instead, it'll be morning clouds, partial afternoon clearing with highs in the upper 60s. And don't ask about next weekend unless you're a rain fan. Suffice to say, I don't think we'll be calling anyone bragging about the weather... unless they are rain fans stuck in Arizona or something :)
-Scott Sistek
KOMONews.Com Meteorologist
