What’s Ahead?

May 31, 2010

The summer weather (July & August) that followed the 5 wettest Mays in PDX history.

So what happens after the 3rd wettest May in Portland’s history?  To be honest I don’t think anyone could really tell you; but I do think we can probably rule out one thing.  People have asked me if this means a cool and wet summer.  That appears unlikely based on past history here.  I looked up the June, July, and August weather that followed our 5 wettest Mays on record here at PDX.  Notice that only one was really a “bad” summer;  1993 was widely known as the “summer of green tomatoes” here.  Lots of cloud cover and marine air; plenty of rain as well.  Luckily that was the one summer in my adult life in which I wasn’t living west of the Cascades.  I was working for a private weather company in Hood River at the time…that was probably the sunniest summer I’ve ever experienced because they don’t get the low clouds over there east of Cascade Locks.

Notice also that two of those very wet Mays were followed by horrendous fire seasons over and east of the Cascades.  The Blue and Wallowa mountains were nailed by historic wildfires…likely due to lots of green growth in the last spring that dried out later in the summer heat.  The same thing is happening this year; well above-average rainfall in normally dry areas eastside.  I know the dryland wheat farmers are ecstatic over the regular dousings from either thunderstorms or stratiform precipitation this month.  And the chilly weather keeps the evaporation down too.  Should be the best weather conditions for those folks  in north-central Oregon in 10-12 years.

Not much weather on the way Tuesday, but what a system coming in Wednesday!  Looks like a (brief) wintertime pineapple express….high precipitable water, high freezing levels, strong southwest winds in the upper levels etc…  I don’t see any chance for river flooding since the rainfall is pretty much gone by late Wednesday afternoon.

The second system coming through late Thursday night and Friday morning is sure one to watch.  Latest models swing a deep low up the coastline with the usual strong southerly wind along the coast and more rain; hard to believe it’ll be June 4th!   We “laid low” on the 7 day forecast for any significant warming Sunday and Monday.   Earlier models have been very warm Monday and Tuesday, now I see the 00z GFS is cool, but the GEM is still real warm.  Seems to be a trend for some ridging along the West Coast, but when it takes hold is most definitely yet to be decided.  If we make it past next Wednesday with no 80 degrees it’ll be the latest ever here in PDX-town.  The “record” isn’t exactly something that will go down in history (who even knew that record existed?), but a good benchmark for a cool spring.

Chief Meteorologist Mark Nelsen

Record Cold Day

May 28, 2010

We only hit 57 at PDX today due to the late morning arrival of the rain and thick (very thick!) cloud cover.  That’s the coldest May 28th (high temp) on record.  Last year we hit 86 degrees on this date…

I spent a couple hours down at the Waterfront at the opening of the Rose Festival Fun Center.  Whew…it’s going to turn into a mucky mess soon if the rain doesn’t stop.  Strong northwest flow is sending moisture on south out of Washington.  Models seemed to handle this well, with about a quarter inch so far here in the city and heavier totals to the north and east.  I expect .75-1.00″ before it’s over in the Cascade foothills.  Just another May soaking apparently.  We should crack the “top 5″ of May rainfall tonight at PDX, passing the 4.30” mark soon.

Much better conditions tomorrow afternoon and Sunday (wow…2 dry days???).  We haven’t seen two consecutive dry days in two weeks!  But don’t breathe a sigh of relief yet…more soakings next week for the first week of June.

Chief Meteorologist Mark Nelsen

A Rainy Friday

May 28, 2010

Just got in and looked over the weather maps, radar, satellite etc…if you have outdoor plans cancel them for this evening…yuck!

Significantly better tomorrow afternoon and Sunday, then back to “sluggy” weather again on Memorial Day itself.

The Slug Fest Continues

May 27, 2010

After checking the maps, satellite, radar etc… this morning I decided this was an appropriate image for the day…I’ll be headed outside to load up the garden again on slug bait soon!  A brief break from the showers this morning after another very wet day yesterday.  I had yesterday and today off since I’m working the weekend coming up, but what a waste of a late May day!  Twice I tried to get outside and do something useful and twice I was chased back in by downpours.  Here’s where we are in PDX-town with our cool and wet May:

1. Temps: Average so far is 54.7 degrees, the coldest May since 1991 (twenty years!).  Still not in the top five, but getting close to the 1977 & 1978 Mays which were back to back chilly (around 54.0 deg).

2. Rainfall: 4.05″, Still just the wettest since 2005…just another 1/2″ would put us in the top 3.  We’ve had rain 10 out of the last 11 days here in Portland.  Parts of town had measurable rain on that one day when only a trace fell at PDX. 

I’ll be stopping by the store to pick up new corn and sunflower seeds…I think the ones I planted 10 days ago rotted…we’ll find out when the temperature finally breaks 65 degrees here at home and things start growing again.   As for this weekend, I have doubts about Saturday…it could end up being a wet day.  I’ll be back at work tomorrow afternoon.

Chief Meteorologist Mark Nelsen

The Natives Are Getting Restless!

May 25, 2010

I think today we reached the “tipping point” with respect to our wetter and cooler than average weather…specifically the last 10 days.  Those thunderstorms dropped up to 1/2″ of rain on the west slopes of the West Hills this afternoon.  That along with highs just reaching within 3-5 degrees of average really set some folks off.

There has also been a lot of false or at least somewhat incorrect information flying around on TV and in emails.  For one, it’s not a record cold or wet May (as of now).   We are neither in the top 5 for rainfall (so far), or temperature (we won’t be).  So we’ve had colder Mays and wetter Mays for sure.  It will probably end up the wettest May in at least 5 years and the coldest in about 10 years.  And it’s not THAT unusual to have 9 out of 10 days wet in late May, but it only happens every 4-5 years.  Scan through May rainfall totals through the last 30-40 years at PDX and it seems like that’s the “return interval” for a wet May.  Basically we’re paying for those warm and sunny Mays of the past.  Remember last year we had almost two solid weeks of 70-90 degree highs!

For those of us that are weather-savvy, what’s probably most noticeable is the lack of “heat waves” or at least warm spells.  We have only hit 76 so far this May…back in 1991 we only hit 75…the only other time we haven’t made it to at least 76.  Considering the weather maps the next 7-10 days don’t look too warm, our 80 degree record COULD be in jeopardy.  The latest we’ve hit our first 80 degree temperature at PDX is June 9th.  I sure don’t see an 80 degree day through at least June 2nd or so.  Keep in mind that although the summer of 1991 (that chilly/wet May) took forever to get started, it lasted well into the Fall.  September through mid-October had day after day of 80+ weather.

I also just now noticed the two wettest Mays ever were followed by hot summers and severe fire seasons in the Pacific Northwest.

Chief Meteorologist Mark Nelsen

Thunder Approaching Metro Area

May 25, 2010

A nice line of heavy downpours with some lightning embedded is moving into the south and east parts of the metro area at 2:30pm.  Expect these to move right across town so we are all going to get soaked (or at least most of us).  Our 4km RPM showed a few pop-up heavy showers this afternoon (at 00z last night), so apparently it did pretty well.  I had added the wording of “possible heavy showers P.M.” for the late shows last night based on that.  But this image looks real juicy doesn’t it?

Chief Meteorologist Mark Nelsen

Yuck…Cold & Wet!

May 24, 2010

I just spent 3 days of the coldest camping I’ve ever done.  Luckily it was in a rented RV so we stayed nice and toasty.  Two days in cold and windy (but dry) southern Wasco county, then a drippy/flurry/cold night at Timothy Lake.  That was interesting there at Timothy Lake (Hoodview campground) because site after site was reserved for Saturday night, but only 4 sites (out of maybe 40?) actually were occupied.  Clearly a LOT of people cancelled camping plans for the weekend before Memorial Day.  Good move…we stayed inside most of the time.  I also ran into snow flurries on my bike ride up around Barlow Crossing on the White River Saturday too.  Don’t want to repeat that, as I’ve never cycled with snow falling either.  By the way the picture above is from Timberline Lodge area on Mt. Hood this morning.

So I’m afraid to go out and check the veggies I planted a week or so ago.  Are they alive?  We’ll see.  It has only been above 50 degrees for a few hours one day in the past 5 at my home.

A brand new trough comes down the West Coast this week, not really attempting to “kick out” of here until the weekend.  I see the 00z ECMWF had another weaker trough sliding overhead this coming Sunday/Monday…if so that would finish off any possibility of decent weather for the big holiday weekend.  Looks like we’re getting payback for the dry and warm late Springs we’ve had the past few years.  More of the same…hail, rain, sunbreaks, etc…

Chief Meteorologist Mark Nelsen