Warm & Dry Spell Continues

May 6, 2013

Monday…10pm…

What an incredible weekend!  Two days in the 80s here in Portland and now on Monday we hit 84 degrees.  And that’s nothing compared to the Ocean Beaches.  The southerly surge of cool air coming up the coastline held off until Sunday evening.  That means BOTH days were in the 80s from the tip of the NW Washington coastline all the way south to near Brookings.  This might be just about the only time I’ve seen the entire coastline in the 80s for two consecutive days; and it lined up over a weekend.  It’s safe to say that most likely this was the only time this warm season we’ll see both of those (heat & weekend) line up so perfectly out there.  Check out the dramatic change in temps from yesterday to today:

MarkCoast_Hot_CoolTemps2

Back here in the valleys the dry east wind and warm temps have dried the soil dramatically.  We haven’t seen any significant rain in two weeks.  My freshly rototilled garden beds are very dry; this is the first time in years that I’m doing widespread watering the first few days of May.  I’m doing that because I see no rain for at least another 5 days; usually in early May we would see dry and warm followed by wet weather.  On the plus side, it’s the first time I’ve planted corn in early May too.  I live at 1,000′ on the west slopes of the Cascades…cool and wet spring weather is the norm.  We’ll see how it does this time around; the plan is to get it up and a few inches tall before some sort of  cold and wet pattern hits later this month or in early June.

Speaking of dry, I added up the rainfall at PDX for spring so far through May 6th for all the years at PDX.  It turns out this spring has been one of the top 3 driest so far here in Portland.  And it’s definitely the first real dry one since 2004.

MarkRain_DrySpellFacts

There were a few years just as dry or drier for March/April, but all had some sort of soaking in early May.  There have been many reports of small fires over the weekend with the dry east wind too; so the assumption might be that we have a really bad fire season on the way?  Not necessarily so:

MarkFire_AcresBurnedOregon_Studio

Notice the lowest acreage burned in Oregon the past 9 years?  2004!  How did we have such a dry spring and early summer and still avoid big fires?  I don’t remember exactly how that year played out firewise through mid August, but I do clearly remember that heavy rains fell in the 3rd week of August, totally drowning out the fire season.  Basically autumn began very early that year; so no fire issues in late August through October.

Where are we headed short-term?  We are in the “Rex Block” right now with an upper level ridge covering us and areas to the north and west.  An upper low is sitting off the California coast spinning moisture for thunderstorms through that area and southern Oregon.  That won’t change much the next 2-3 days, but then it heads off to the east.  Over us we are getting a weak marine push this evening, but our RPM and WRF-GFS keep the intrusion shallow with very little morning cloud cover the next few days.  850mb temps remain very warm under the ridge…+11 to +14 through Thursday.  Then the ridging strengthens a bit with temps warming Friday-Saturday.  We’re probably going to see 80s again at least those two days.

Models are in very good agreement with a cold front moving onshore Sunday.  There is a nice southwest flow aloft on Sunday and maybe Monday too, so hopefully we’ll get a good soaking of rain then (can’t believe I just wrote that in early May!).

Then both the ECMWF and GFS are hinting that the ridge may rebound for a few days, more of a June pattern with a weak cold front passage followed by a quick return to dry weather.  We’ll see how that pans out.

Here are the latest 12z ECMWF and 12z GFS ensemble charts.  First the GFS:

tseries_850t_000-384_Portland

Notice the sharp drop to average temps behind the cold front and then warming next week.

Now the ECMWF.  Not as much ridging on the operational run, more typical mid May weather starting early next week:

tseries_850t_000-360_Portland

Enjoy the sunshine!

Chief Meteorologist Mark Nelsen


ECMWF Monthly Maps

May 6, 2013

9:45pm Monday…

The monthly run of the ECMWF model from Sunday night.  The weak trough over us the 2nd half of the month doesn’t seem to show up as it did on last week’s run.

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Chief Meteorologist Mark Nelsen