Cool May

As the tag line suggests, it looks like much of May will be on the cooler side of Spring, with minor amounts of precipitation.  Mug ready here, how about yours?

First, let’s deal with the periods in May that could possibly present some precip.  Unfortunately, those periods are likely to fall on the weekends.  However, please note that nothing on the charts indicates super-wet weekends, or enough rain to provide a needed "Nature’s watering”.  (At least that is what wx models have been indicating for quite some time.)  Therefore, expect cloudiness to sneak in mainly around the Puget Sound region on Saturday, with a broader shift to clouds & the chance for showers arriving across the entire PNW by Sunday as the Low we have mentioned several times develop along the southern coast of Oregon.  

On Monday May 12, that same Low will slowly move over the NW corner of CA, resulting in clouds & showers extending north into OR, esp southern OR.  Washington state may miss out on the scattered showers, although a few could pop up along the eastern slopes of the Cascades.  By Tue, clearing & cool temps will remain in play around the PNW through the rest of the week (May 13-16).  Periodic westerlies through the Columbia Gorge will keep windsurfers happy, but the wind drag on river barges will ‘burn’ a bit more fuel.

The weekend of May 17,18 should present another chance for cloudiness & precipitation.  Late Fri, a front will begin to move onshore - broadly up & down the PNW coast - and could be strong enough to set off showers region wide, with the heaviest likely over the southern 1/3 of OR, both sides of the mountains.  Models clear things out again on Sunday. the 18th.  Temps will remain a tad cooler than normal for mid-May.

May 19-23 looks dry, mild to start, however, by Wed, charts indicate a cold front (esp chilly for late May!) could move in from coastal BC, for a chilly end to the week.  Not a lot of moisture is modeled, but temperatures - IF the sky clears in your location - could tease a light frost on Fri morning, May 23.  

Holiday Peek:  That chill will NOT mess up the Memorial Day holiday weekend.  A warmer pattern is likely, with High pressure ridging into the PNW ahead of another system developing offshore - threatening some precip late Memorial Day or Tue May 27.