Back From Vacation: A Warm Week Ahead

March 11, 2013

Back at work and all rested up now from that exhausting winter weather…wait, I think winter ended back in late January.  I don’t think I missed anything in the past two weeks either.  Here are the highlights today:

  • Warmest weather of the early spring (or late winter if you prefer) for MOST of Oregon this week, but not much sun over Portland, just mild.
  • Wet week up in Western Washington, but more dry than wet south of Portland/Tillamook
  • There will be no repeat of last March’s cold and occasionally snowy weather, my studs are coming off this week even though I live at 1,000′.

The main story this week is mild, mild, mild, and only a little rain.  Temperatures have been a little below average so far this month but this week will more than make up for that.  A very weak ridge is over us most of the week with a late season “atmospheric river” of rain aimed just to our north.  You can see it on Wednesday morning’s water vapor forecast; quite a plume of moisture from near Hawaii up into Cascadia-Land:

pcpwv_48_0000

Take a look at the 48 hour rainfall forecast (through Wed. AM) from the  WRF-GFS:

pcp48_48_0000

Almost dry across Oregon, but 1-4″ rain across the northern half of Washington.  We will be right on the southern edge of the rain band most of the next 3 days; always a real pain for forecasting.  This is also the dividing line between cooler air to the north and very warm subtropical air to the south.  We are out of the inversion season now in March, so areas to the south that see the rain stop will make it into the 60s.  Areas farther south, maybe Florence to Eugene to Pendleton, could see highs close to or up to 70 either Wednesday or Thursday.  What a change from last year eh?

Beyond Friday, unusually low confidence with an interesting ECMWF ensemble chart:

tseries_850t_000-360_Portland

Notice two clusters of ensemble members in the Saturday-Monday timeframe.  It’s because some runs have a chilly trough moving through, but others just shove it to the north and leave us mild.  That was the ECMWF, the GFS 6z version was colder:

tseries_850t_000-384_Portland

Although I see the brand new 12z GFS is milder Saturday, still a cool trough Sunday and Monday.  No model produces a ton of rain in the next week, in fact it appears to be lighter than average again.  This is a continuing pattern we have seen since the beginning of the year.  Look at the 2 month rainfall anomaly across the West. 

anomimage

Below average for most areas, many parts of Eastern Oregon and into California have only seen 50-70% of “normal” rainfall.  We’ve seen lots of split flow and ridging nearby (usually just offshore).  That’s going to continue.

Chief Meteorologist Mark Nelsen