I heard some interesting responses as to why the pattern did not move forward as anticipated 2 weeks or so ago. Over the last two months each of the MJO passages were followed by a big downwelling couplet. This latest one has not featured that and in fact combined with a standing wave at the dateline. So there might have been enhanced mass transport north...IE fueling the PAC jet. We finally are seeing a Nino response.
I think once that subsides it will help force more of an Aleutian low. Indeed you can see that on guidance.
I'm just using an old man rule of thumb. It's hard to get ZR from a coastal.
Unless, we had a sharp front aligned more N-S and stalled over the Cape I suppose.
I definitely would keep an eye on that system early next week. Low chance, but like Will said that high building in this time of year is always kind of an eyebrow raiser. The question is how much moisture is around to play with.