Over the past week, the weather in the Pacific Northwest has taken a dramatic turn.  Back in late March and early April, we were under a continuous two-week stretch of clouds, rain, cool temperatures and fairly low snow levels.  In fact, it was the coolest March at PDX since 2012!

But now we’re enjoying tons of sunshine and mild temps instead.  Last week we had a glorious 3-day stretch in the 70s.  Lots of dry 60s too.  And the next week looks like even more of the same.

Thankfully, most Portlanders are enjoying the sun at a socially safe distance.  On Tuesday when it was 73 degrees, I took a walk on the Oaks Bottom path in Sellwood.  Walkers and joggers were spaced an impressive distance apart.  Even in Westmoreland Park, people were mostly keeping space.  The only culprits were three basketball players on the court.

Today we had an interesting twist to the weather:  cool northerly flow out of Canada brought extremely dry air; at one point this afternoon both relative humidity and the dewpoint were in the upper teens!  That dry airmass also means that despite tons of warm sunlight during the day, it cools off quickly at night.  Last night it dropped to 37 even at the airport, and in my neighborhood there was light frost on rooftops and cars (34 degrees?).  I expect tonight will be much the same, maybe even a degree or two colder due to lower humidity.

Higher sun angle aside…I guess you could say that today felt kind of like a typical sunny day in early October, when nights are clear and chilly but it gets into the upper 60s / low 70s by day, with light easterly wind and low humidity.  Today’s high temperature was 66 at the airport.

Would you believe we’ve seen only 0.18″ of rain since April 1?  There’s been no rain at all for 8 days now, and it’s possible we could have another 7-10 days which are nearly bone dry.  Today there was even a small brush fire near Longview.  I didn’t have the time tonight…but in a couple days I may dig up the current drought maps and post them on my Facebook page.

The pattern ahead looks nearly identical to the last week.  More sun than clouds….no rain, temps near to above normal during the daytime and relatively cool at night.  The 12z GFS operational map showed less than 0.2″ of rain for the next 10 days!  Nearly all the action dives down to our east, while Pacific storms remain blocked by a large area of high pressure.

Normally the West Coast would be much wetter than the Intermountain West at this time of year.  This is a testament as to how ‘constipated’ the northern jet stream is at the moment.

The 12z ensembles look similar, though they suggest a slightly better chance for a few showers about 5-7 days from now.  But it should be noted that the 06z and 18z were significantly drier than the 12z.  If the drier solutions hold, we could potentially see less than 1/2″ over the next two weeks…and potentially less than 1″ for the entire month of April.

Needless to say, unless things turn very wet in the last week of the month, April 2020 will go down as another very dry month.  Since the start of the water year on October 1, 6 out of 7 months have been much drier than normal (only January was wet).  We’re quickly running out of time to make up the rain deficit.  A wet May and June could still help us out.  But if not, then I suspect it won’t be long before drought becomes a topic of our regional weather discussions.  Dry east wind would also put us at risk for some fire danger, even in the springtime.

In any case…expect relatively boring weather to continue, for the foreseeable future.  -Karl