The last couple days, weather geeks and non-geeks alike have turned their eyes to the coast of East Texas and West Louisiana, where hurricane Laura is in the process of devastating communities with 150-160 mph winds and 20-foot storm surges.  It is the worst storm disaster along the Gulf Coast, since Katrina struck 15 years ago.

And in much of the Western U.S., the skies have been clogged with smoke for weeks now.  Horrendous wildfires in California and the Intermountain West, are blazing out of control thanks to the drought conditions brought on by a changing climate.  Here’s a photo from a couple weeks ago, credit of NOAA.gov and brought to my attention by Grant Otis McFarland:

Yet here in the Pacific Northwest, our weather couldn’t be more “perfectly boring.”  Since the end of the heatwave more than a week ago, we’ve been blessed with near-perfect conditions:  not many morning clouds, lots of sunshine, and temps in the low-mid 80s most afternoons.  We had one muggy/rainy day (Thursday) with a high of 78.  There has been enough west/northwest onshore flow most days to keep temps mild, and push the smoke further east.

What’s coming up for our corner of the world?  Well…this mild and sunny weather pattern is expected to persist for at least the next 10 days.  Late summer glory will drag on into early September!  

But at the same time…we’re starting to see some “interesting” (i.e. fall-like) developments on the weather maps for the North American continent.  It always seems to start popping up at some point in the latter half of August, or else very early September.  That’s because the arctic and subarctic regions begin to cool rapidly as we move through late August and early September; the effects of decreasing sun angle are felt sooner as you move closer to the poles because the sun is never that high in the sky to begin with.  (Also the decline in daylight hours is more dramatic, the further north you go.)  This early-fall ‘arctic’ air then begins to dive southward into troughs in the jet stream, just like it does during winter cold blasts.  

A few days ago the long-range models were showing a strong autumnal trough over the Pacific Northwest for the upcoming weekend (August 29-30), with 850mb temps over Portland possibly dropping to +5 or colder (normal is about +13!).  That would have given us a sharp taste of early Fall for the final weekend of August.  But now the models have backed off on the intensity of the cool air, and are keeping more of it east of the Rockies after the weekend ends.  Here is the glancing blow of cool air, as of Sunday morning per the 12z GFS:

This would be cool enough to drop places like Portland into the 70s for highs, for a day or two.  But then look what happens by the latter half of next week:  a strong and warm ridge has entrenched itself once again along the West Coast!  More temps in the upper 80s or 90s are likely, if this comes to fruition:

Meanwhile, chilly Canadian air continues to dive down east of the Rockies.  The NCEP’s 6-10 day outlook shows this warm West Coast + cold Rockies/Plains pattern very clearly for late next week.  I didn’t download the precip map, but the entirety of Washington and Oregon look drier than normal.

So we’re almost certainly going to stay mostly dry and sunny for the next 10 days, possibly even 12 days or longer.  What we don’t know is whether any of that cold air to our east, may decide to retrograde and send a cool northeast wind into the Columbia Basin and ultimately the Gorge.  I seem to recall that very thing happening in September a few years ago (2014?) where an early-season ‘arctic’ high pressure pushed some chilly dry air into The Dalles.  

Even if the upper level pattern remains sunny and mostly warm for the next two weeks…we’re going to notice the nights getting cooler as the season continues to press on.  We have already felt the last few nights getting a bit cooler, as darkness continues to lengthen.  That will become even more pronounced as we get into September, as long as skies remain clear and dewpoints relatively low.

On another note…California is expected to remain hot and dry throughout this entire period, and the chilly high pressure over the Rockies will only make the Santa Ana winds worse.  This is not a fun time of year to be living there, especially in a fire season as bad as this one!

And please send your wishes, prayers, and hope for the Gulf Coast, that they don’t have any more brutal hurricane landfalls this season.  -Karl