A Big Change?

There is a possibility that a significant change in the long-range outlook is developing.  Not definite yet, but important for us to consider the impact late month, esp on fall harvests.  For now, grab your fav morn’n beverage and read on.

Today will be pleasant, as we wait the arrival of fall-like rain tomorrow.  Models suggest a quarter-to-half-inch of precipitation is possible around the region from the coming system.  Expect Tue to be cooler & WET.  The rain should diminish overnight Tue, with scattered showers lingering early Wed.  The balance of the week will be dry & pleasant.  Scattered showers in California.

The wx this coming weekend is not quite ’settled’ by the models.  It could be WET from Chehalis north; dry & mild for OR and to the east, or mild with increasing clouds & chance for showers regionally by Sunday.  

🫤 Why the uncertainty, especially given that precious charts indicated a dry pattern for the balance of September?  The problem, as we see it, is that models are struggling with a potentially large scale shift in the overall upper level wind pattern.  Meaning - - a change to a classic period of fall rains, wind and generally stormy weather for a week or longer.  Gone would be a dry end to the month.  Given that potential, we will posit the following forecast, right or wrong.

Whether or not the coming weekend remains unsettled, NEXT week will begin the change to a WET & stormy pattern, as the ‘jet stream’ shifts to favor such development.  Therefore, expect the wet system over Vancouver Island Sunday night to continue spreading south into the entire PNW by Tue Sep 24.  Breezy.  Showers post-frontal passage are likely Wed & Thu.  A break on Fri, with sunshine and mild temps before another much wetter system arrives overnight Fri the 27th into Sat.  Heaviest rain will fall north of Portland.  Sip.

On Saturday the 28th, another storm will develop farther to the south, the center of which will push onshore around Astoria.  Heaviest rain will fall in the Willamette Valley, south.  Concurrently, in the Gulf of Alaska, systems will begin to deepen into powerful fall storms, the first of which will make landfall in the Alaskan Panhandle, but have a large rain (and wind?) field that keeps the PNW wet late Mon into Tue Oct 1.  The Puget Sound region will likely to be hammered with rain.  Cumulative precip throughout this period could exceed 2 inches in the lowlands, 4-6 inches in the Cascades & coast range; more so for coastal BC.

The details above are likely to vary, of course, but the point here is to prep you for a week of wet weather as the month of September ends.  (Long-time Patrons know that often model outlooks revert back to earlier progs as the solution, so all this rain talk over coffee could be null & void.)  We’ll see what charts on Friday.