Near record chill in first half of October. Harbinger for the coming Winter?

Warmer for a change!  On Saturday, several locations around Snoqualmie Valley reached 70°, in stark contrast from the first half of October, that clocked in an average high of about 57°.  Possibly right there with the record lowest average official high of 56.7° set in 1913 at Snoqualmie Falls (depending on differences in exact location, weather instrument accuracy, sun exposure, etc.- then and now).

So the question making the rounds in the weather media the last week or so - Does a really cold start to October foretell a cold fall/winter season ahead?  

Looking back at local data (station: Snoqualmie Falls) that was available for 122 years (1898-2010) shows the answer is .. not so much. 

I looked at the coldest average high for 1H Octobers and worked upwards in rank until I had at least an n=30 (years).

What I found was the coldest ~15th percentile bucket of first-half Octobers (calendar days 1st-15th) do not appear to show statistical significance in forecasting the subsequent November, December, January or February.  Those subsequent months have average high temperatures right around the 50th percentile.

In attempting to make a long-range forecast for the months ahead, hint: any way you slice it for the lowlands, it's mostly a crapshoot. We're better off turning our attention to the La Nina (generally cooler and wetter period for the PNW) that is expected by forecasters for the coming months.  The historical data does show that would be good news for skiers, but the probability of more frequent cold snaps, or snow events for the lowlands is mostly a coin flip. 

Anecdotally speaking, the greater snow events since I'm lived out here in Snoqualmie @ 800ft elev. were:

- 2008-09 (38") - La Nina 

- Feb 2019 Snowmageddon (40") - El Nino 

- Jan 2020 Janmageddon (18") - Neutral

It's also worth noting that "Neutral" fall/winter seasons can be all over the map, leaning towards being years of more extreme flooding or wind events.

So there you have it.  Clear as mud for the winter ahead, right?!  

In the shorter-term, more active weather looks to return mid-week. Beyond that, hoping for a dry Halloween for the trick-or-treaters.