A Very Different July & A Nice Weekend Ahead

July 12, 2019

9pm Friday…

What a spectacular summer day, not hot, humid, or cloudy & cool. The comments I keep getting are that this is “just right”.  Today we hit 84 in Portland, above the average high of 80.  Warmest day so far this month.  We’ve also seen a string of warm nights recently, this morning was our 4th staying above 60 degrees.   The humid weather from Wednesday is long gone too, dewpoints briefly even dropped into the 40s late this afternoon.

This July has been…NORMAL temperature-wise, but cloudier than average.  Out of 12 days we’ve seen NO clear days, 8 partly cloudy days, and 4 cloudy.  I suspect that’s the reason I’ve been seeing some complaining online.  If you want to hit the local lake/river/pool, it’s much chillier to do it under cloud cover.  In fact yesterday/today was the first time I’ve made good use of my Craigslist-special pool this season.  I was out of town for that heat wave in early June.

Todays Observed Highs OrWa 2017

As mentioned in the previous post, we are overdue for an “average” summer instead of another blazing hot one.  Even with a warming globe, that doesn’t mean every year turns warmer and warmer in a steady line.  There will still be the usual ups/downs and cyclical periods; but the GENERAL movement will be uphill over time.  Also, we’ve had many summers that are about average in July and then August/September turn hot.  We’ll see.  Last year the blazing hot summer kicked into high gear on this date.  The following 19 days were crazy, all except 4 above 90 degrees:

July 2018 Historic Heat Wave Stats

I know some of us want more sun and hot temps, but the 84 today was sure nice in comparison.

This weekend looks pleasant again with a relatively thin marine layer leading to plenty of afternoon sunshine each day.  On Monday that layer thickens a bit so expect more cloud cover for the start of the work week.  850mb temps (temperature in celsius around 4,000′) drop a little Monday as well as a weak upper-level trough moves overhead.

As I mentioned in the post early this week, an unusual (for mid-summer) setup is on the way for later next week.  A highly anomalous deep trough cruises across the Gulf of Alaska midweek and drops into the Pacific Northwest late next week or the weekend of the 20th.  Check out the 500mb anomaly chart for Wednesday and again Friday

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That’s what we might see in June, but unusual for July.  At this point it appear most of the significant rain may be headed for Washington and BC.   Oregon would see far less.

How much rain down here?  Initial look, remember it’s 5-7 days away, but a tenth of an inch in the western valleys and less than 1″ in the northern Oregon Cascades seems like a good guess.  Here’s the 12z ECMWF model forecast:

ECMWF Precipitation Accumulation

Enjoy your weekend and keep in mind that we MIGHT see showery/cool weather about a week from now.

Chief Meteorologist Mark Nelsen