Changes next week and new fall/winter outlooks

Enjoying day after day of sunshine?  How much longer will it last?  In this blog we will address this important question, but also take a brief look ahead into November and briefly touch on the winter outlook.  A more detailed winter outlook blog is coming on or near November 1st. 

So why the abundant sunshine and stretch of dry weather?  A persistent ridge of high pressure is the answer.   Here is one model forecast for this Sunday (Oct 21st) showing high pressure deflecting the jet stream well north of our area.

18z GFS forecast of 500mb heights and 250mb winds valid 5 PM PDT Sunday October 21st

This will be a great weekend for yard work.  Especially raking all those leaves!

There is good model agreement that dry weather will last through at least Tuesday morning.  A weak system tracks through late Tuesday and Wednesday but probably won't produce much rain if any.  Models agree of a wetter pattern developing around Thursday (Oct 25th) of next week.  A low pressure system sets up off the coast resulting a mild but potentially wet southwest flow.  Here is one model depiction of what the pattern should look like next Friday. 

18z GFS forecast of 500mb heights and 250mb winds valid 5 PM PDT Friday October 21st

The jet stream (noted by the green and orange shaded colors) becomes aimed at Washington and north Idaho.  The latest 6-10 day Climate Prediction Center outlooks support a wetter pattern as well.

CPC 6-10 Day Precipitation Outlook issued Oct 18 valid Oct 24-28th, 2018 

It's still too far out to talk about rain amounts and will ultimately depend on the exact placement of the jet stream. 

What about November?  The new outlooks issued today (Oct 18th) favor elevated odds of warmer and drier than normal.

CPC November 2018 Temperature Outlook issued Oct 18 

CPC November 2018 Precipitation Outlook issued Oct 18

And what about the winter you ask?  Well an El Nino winter is forecast which has historically brought mild winters to the Inland NW with precipitation more of a wild card.  The new CPC outlooks issued today (Oct 18) mimic this idea as shown below.

CPC Dec 2018-Feb 2019 Temperature Outlook issued Oct 18 

CPC Dec 2018-Feb 2019 Precipitation Outlook issued Oct 18 

But don't think that a mild winter means no significant weather.  Short term significant weather events can and do occur.  In the next blog we will go into more detail with the past three weak El Nino events (2004-05, 2006-07, 2014-15) and look at what happened.