Summer in May

It is a climatological oddity of Northwest meteorology that we often get a period of very warm, dry weather sometime in the second or third week of May, followed by a retreat into the dismal June Gloom.  Well folks, we are about to have the heat wave--one that will bring near 80F temps to Seattle, 85F to Portland, and near 90F in Medford.  The latest National Weather Service forecast for Seattle says it all:

The interesting thing is that for the last few days we have had fairly cold air over us, and with relatively clear skies and good radiational cooling to space, temperatures have fallen well below freezing in the cooler spots.  For example, it got down to 19F in Redmond, Oregon early Thursday morning---here are the minimum temps that morning...plenty of 20s and sever teens!

The was so cold aloft that considerable instability was produced as the surface was heated by the strong May sun....producing some impressive cumulus development.  Take a look at the UW cam image at around 7:30 AM and three hours later...you can see the destabilization due to surface heating:

During the next few days you will see progressive warming...lets look at the predictions by the UW WRF model for 5 PM on Friday, Saturday, and Sunday.  The light pinks and whites are in the 70s and higher.  You don't need to be much of a meteorologist to understand what this means....

White hot!   Clearly, the mothers in the NW are particularly deserving this year.  Amazingly, it s our fifth good weekend in a row.  And Monday will be warm as well.  Even your tomato plants will be happy.

Final reminder for those near Portland...I will be talking at OMSI Science Center in Portland at 10 AM, looking into the future of weather prediction.   The lecture is free, although the Oregon Chapter of the American Meteorological Society will be raffling off a fancy weather station and one of my books.   This chapter is one of the biggest and most active in the U.S. and recently they had some highly controversial sessions with both sides of the global warming debate.