Atmospheric Shuffle Possible

 

The holiday weekend that traditionally shifts us from summer to fall is just about over.  Our Patrons are fully aware of the variability in long-range forecast models, hence, it remains a morn’n tradition (since 1994 for some of you) to sip a morn’n bev from that special Mug to ponder the various weather patterns that may develop in the weeks ahead.  Thanks for reading The Weather Café ®️.

 

Broadly speaking, there may be a shuffle in the atmosphere sometime mid-month.  That shuffle could FINALLY introduce the possibility of notable precipitation across the PNW.  Will it happen?  For now, expect dry and on/off WINDY conditions to prevail through approx. Fri Sep 17.  By Thu this week, temperatures will cool down a few degrees, as the onshore flow picks up.  Breezy afternoons.  Nine-Eleven looks dry, pleasant.  Warmer & breezy on Sunday Sep 12.  Good sailing in the Sound? 

 

The week of Sep 13-17 charts as starting out WARM.  A ridge of High pressure will be positioned to bring on a couple rather WARM afternoons.  Upper 80s to lower 90s possible, esp in OR.  By mid-week, the early stage of that “shuffle” may begin, with cooler onshore flow increasing notably because a trough digs southward from the Alaskan panhandle, coast of BC.  NW winds, which could be strong east of the Cascades.  Concurrently, High pressure over the interior of Canada may begin moving south, east of the Rocky Mtns.  

 

Last week, we were looking at that same High movement to be centered farther west, setting up very windy conditions for portions of the PNW.  Model runs have shifted that threat, and in doing so, opens the door for Low pressure to move in from the NW - meaning RAIN possible in the Sep 18 - 20 period.  Not a promise, just a ponder point for now.  It will be WINDY CITY for northern tier states of the US heartland.  This whole outlook is variable, depending on where that High pressure is centered.  The pressure gradient will be from west to east, therefore, a strong east wind event is NOT probable.  

 

As you can tell, model solutions vary considerably for our weather during the Sep 16-20 period, with solutions ranging from dry, warm to windy, cool & damp.  Since the later solution has charted the most, it warrants our mention here as possible.  Sip & Ponder.