The Cold & Wet Weather Is Here

May 21, 2013

What a change this afternoon.  Take a look at the temperature change from 6pm Monday to 6pm Tuesday:

MarkTemp_SinceMidnightPDX

We were 23 degrees lower here in Portland!  Around noon I was doing some errands on the eastside of town, getting irritated at the lack of rain (I don’t like a bad forecast).  But that forecast turned out perfect this afternoon…what a downpour.  It was our first good soaking in about 4 weeks, very much overdue:

MarkRain_PortlandToday

The cold upper level low has definitely arrived hasn’t it?  850mb temps over Salem this afternoon were measured between -2 and -3 degrees celsius.  That’s just about the core of the cold air, so it won’t get any colder than this.  The bad news though is that the upper-low isn’t going anywhere from now through Monday (Memorial Day).  That means we have a chance for showers through the Memorial Day Weekend.  The coldest/heaviest showers will definitely be tomorrow through Friday with the coldest airmass.

If you are looking for a return to some semblance of warmer weather, think again.  Take a look at the 850mb ensemble temperature chart from the 12z ECMWF:

tseries_850t_000-360_Portland

Very good agreement that below average temperatures will likely continue for the next 10 days.  Monday and/or Tuesday will be close to average, but at that time we get into a wet westerly flow, so lots of gray.

Here’s the 00z GFS chart, very similar:

tseries_850t_000-384_Portland

So put away the shorts & flipflops, keep the pool covered, and hope your warm weather veggies can tolerate some repeated soakings without rotting.

Chief Meteorologist Mark Nelsen