First 90 in 7 Day Forecast This Year…Sun Next 5 Days Too

May 10, 2012

The next 5 days will feature a taste of June-July temps and weather.  70s tomorrow, 80s Saturday through Monday, and then probably back into the 70s Tuesday.  Here’s our latest 7 Day forecast as of 5pm today:

You’ll notice we are sticking with upper 80s to around 90 both Sunday and Monday.  That 90 is really just a psychological number…we only changed the forecast high by 2 degrees on Monday, but 90 sure seems a lot warmer than 88 when making a forecast.  Regardless, it’ll likely be somewhere between 87-93 in the Portland Metro area and western valleys both Sunday and Monday, with the warmest day for most of us on Monday.  Both the GFS and ECMWF have 850mb temps (around 5,000′) between 17 & 20 both afternoons.  And check out the offshore flow on the WRF-GFS cross-section:

We have 4 days of easterly flow in the lower atmosphere commencing after midnight tonight and continuing through Monday.  East wind will blow through the Gorge most of the time from tomorrow morning through Monday morning, likely strongest on Sunday morning.  The combination of sunny skies, offshore wind flow, and those 850mb temps should be enough to push many of us to right around 90 degrees or even lower 90s…thus the forecast “tweak” today.

There is disagreement Tuesday and beyond on the amount and depth of upper-level troughing later next week.  Here’s the ECMWF 12z ensemble chart:

I notice the operational (blue) run is slower cooling us off than the ensemble.  Our forecast above cools things off quickly Wednesday and Thursday assuming the ensemble mean is probably a better indicator of reality.

The 12z GFS:

shows a little quicker cooldown too.  But it sure stays mild in general through the next 10+ days.  Even I am thinking of planting the warmer weather veggies next week, at least the ones I can “plastic up” when the inevitable two weeks of 55 degree temps and drizzle hits sometime between now and late June.

Chief Meteorologist Mark Nelsen