Back to Cold

April 14, 2008

SnapshotHmm…was this last weekend just a dream?  I think so after the rude shock of chilly temps, hail, and snow in spots, today.  Then I come in and look at model forecasts for this weekend just about fall out of the chair.  Well, not really, but it sounds more dramatic that way.
First, short term:  Cold trough is passing over us now.  I notice it’s in the teens at Timberline and just barely above freezing at the top of our TV Tower.  Some winters it barely gets that cold here!  Snow COULD fall down below 1,500′ tonight, but the showers appear very weak on radar…the Coast Range is killing most of them.  Showers increase tomorrow midday-afternoon as another wave moves down the backside of the upper trough.
Then it’s on to milder weather for Wednesday and Thursday.  Temperatures should be closer to normal.  Somewhere near 60.  Probably dry both days too.

The big story is the agreement by all models on an unusually cold trough dropping in over the Western USA Friday-Monday.   Latest 00z runs of GFS continue VERY cold airmass forecast…just about as cold as what we just saw two weeks ago (4-5 days of snow at 1,000’+).  Since it’s mid April, it’s very unlikely we could see snow on the Valley floor unless everything lines up perfectly.  However, I have a feeling that 850mb temps of -6 to -8 and thicknesses of 516-520 will bring several inches of snow to those spots at/above 1,000′.  My trees about to bloom are toast aren’t they?  But, to borrow from one of my favorite TV shows "this has all happened before and it will happen again".  April 23rd 1961 brought 3" of snow to the West Hills, but none in the city.  The high at PDX that day was 43 degrees.  As far as I know, that’s the latest that snow has been seen in the immediate metro area.  Mark Nelsen