Enjoy the Weekend; A Wet & Chilly Week Ahead

April 27, 2012

Hard to believe, but our 4th weekend of April appears either dry and mild or mainly dry and mild.  Tonight’s warm front, spreading light rain into the northwest part of Oregon, will fizzle and dissipated right over the top of us later tonight and into Saturday morning.  That leaves us with a gray start Saturday, but increasing afternoon sunshine.  Sunday will just be partly cloudy or mostly sunny.  Both days our RPM is trying to generate weak convective showers over the Coast Range and Cascades in the light westerly upper-level flow.  Thus the “mainly dry” wording.  Most likely we have a dry weekend ahead.

Then, it’s on to May!  Unfortunately, the first week of May looks to be unusually wet and chilly.  Early on in the week we get “zonal” flow which is our usual westerly jet stream bringing in cool and wet systems.  Then the latter half of the week (and probably next weekend) a colder upper-level trough digs down over us.  Take a look at the 00z ECMWF’s 500mb anomaly forecast for the 7 day period starting next Monday-Tuesday:

Note the large negative anomaly over the West Coast, western Canada, and Alaska.  In fact the next 7-10 days sure looks like the March weather pattern doesn’t it?  Nice that the heat returns to the eastern USA too.  A peek at the 12z ECMWF 850mb ensemble chart shows below average temps (around 5,000′ elevation) from Monday to next Sunday, the lots of variation after that time.

The 12z GFS is similar, although it holds onto the cooler than average temps a good 1-2 days longer.  Brrr!  

The screaming message is that next week will feature lots of cancelled spring sports practices and games, along with chilly temps and mountain snow down to 3,000′ or even lower at times.  Hopefully you didn’t plant your tomatoes or corn yet!  I just planted tomatoes in my greenhouse I built last Fall.  In there, even on days like today, it gets up to around 80.  A little bit of climate change going on at the Nelsens.

So once again…enjoy the mild and dry weekend!

Chief Meteorologist Mark Nelsen