More Wet Weather Ahead

March 7, 2016

9pm Monday…

Today wasn’t exactly a soaker, but a classic cool spring day with showers/sun/rain/hail all mixed together.  Portland only picked up a few hundredths of an inch.  High temperatures were near/below normal for most of us.

I expect lots more rain over the upcoming week as numerous wet systems move across the Eastern Pacific and into the Pacific Northwest.  The 18z GFS meteogram gfs_meteogram shows only a few brief breaks this coming Friday and Saturday.  As of now I don’t see any strong storms, although something can always pop up just a day to 3 days ahead of time.  There is going to be a very strong surface low developing WAY offshore Wednesday afternoon/night, but it stays right along or west of 130W.  To get damaging wind along the coast and for sure in the valleys you need the surface low closer.  Still, a 990mb low deepening down below 970 mb. will bring quite a strong wind Wednesday evening along the beaches…good storm watching!  Check out the WRF-GFS 70-80 kt wind gusts along the central/southern Oregon coastal waters.  wgsfc.51.0000  That’s strong even for a midwinter storm.

Looking ahead, is there a dry spell in sight?  Yes and no.  Models are trying hard to show a warmer/drier (not dry though) pattern setting in around next Wednesday/Thursday.  That’s about 9-10 days out.  This is the long-awaited change the ECMWF monthly maps have been showing with ridging building to the north.  Note the next 4 weeks of last night’s run showing 500mb heights.  The strong trough offshore weakens and shifts south:

The corresponding precipitation anomaly for each week of the next month:


Are these maps total junk???  That’s a good question.  Cliff Mass gave a great presentation about this subject during the Northwest Weather Workshop in Seattle this weekend.  He showed several examples of the CFS model failing this winter in the 3-5 week period.  We saw that in late November when the 2nd two weeks of the above ECMWF run showed the “canonical” El Nino look with ridging to our north and wet flow into California.  Cliff pointed out we’ve seen this other times in the winter; specifically in February:


His conclusion (likely correct) is that anything beyond 2 weeks kept reverting to that “El Nino Pattern” (in this winter’s case) and models are showing little skill beyond two weeks: cliff2 On a slightly positive note, it doesn’t get much worse after the 3 week period?

Why?  His theory is that tropical convection is not being initialized correctly leading to compounding errors out in time.  Interesting.

By the way, there is a rumor that Cliff may be coming back for a talk in May to our local AMS Chapter!  Maybe a talk about the horrible radar coverage along the coast and central Oregon?  We’ll see…stay tuned.

Chief Meteorologist Mark Nelsen