Spring 2017 Wrap-Up: Wet, but Normal Temps

June 6, 2017

7pm Tuesday

We are 6 days into summer, at least from a meteorologist’s viewpoint.  June through August are the 3 warmest months across most of the northern hemisphere and we’re just 2-3 weeks away from decreasing daylight.

MarkSummerDefinition_MeteorologicalvsAstronomicalSeasons

So after all the wailing about a “cool and wet spring” how did it turn out?  Take a look at temps:

MarkSpring WrapUp

March and April were cool, but then May ended up as our first warm month since November.  So in the end there was nothing abnormal about our temperatures…very close to average, in fact the most “average” since 2008.

Rain?

MarkSpring WrapUp2

Yeah, we know…very wet to start, then suddenly the faucet turned off the 2nd half of May.  So it ended up being the 5th wettest on record at PDX and the wettest spring in 5 years.

Those last two weeks of May were sure memorable…a taste of summer we haven’t seen during that same period in quite a few years.  I always find it remarkable how the “faucet” can just suddenly shut off in the Pacific Northwest.  We go from consistent showers and chilly weather and then suddenly no rain for 3 weeks?  Can’t there be a middle ground?

Looking ahead I see one more very warm day tomorrow, then a classic “Rose Festival Low” moves down over the Pacific Northwest Thursday through Sunday.  Check out the huge drop in temperatures on the ECMWF ensemble chart.  This shows temperature around 5,000′ in celsius for the next two weeks.

tseries_850t_000-360_Portland

The screaming message here is that we’re headed into a cooler than normal period for at least a week beginning Thursday.  There are strong hints that we return to normal or even go a bit above by late NEXT week.

We haven’t seen real rain in Portland for about 3 weeks.  The last time we’ve seen more than .01″ was May 17th!  It’s time.  So how much will see?  It’s pretty clear that most of the rain Thursday and beyond will be in the first 3 days (Thursday-Saturday).  Check out the ECMWF model ensemble showing 24 hour rain totals:

ecm_24hrrain

Each of the 51 ensemble members are on the upper chart and the lower chart shows the average of all the ensembles.  Pretty clear that the wettest period is early on as I just mentioned, but now there are hints of some additional rain trying to show up that following weekend (17th/18th).  It’s something to keep an eye on.

Enjoy the last summery day Wednesday and make sure you have all your dry weather activities done by Wednesday evening.

Chief Meteorologist Mark Nelsen