Oh No! It’s Happening Again

July 19, 2011

Over and over again the past 6 weeks we’ve seen models attempt to develop upper level ridging (even if only briefly) over the West Coast of North America, only to see subsequent model runs squash it down and bring new, cool, upper-level troughs closer to the coastline than originally anticipated.  It’s as if long range models keep attempting to revert to “normal” summertime conditions, but then “clue in” to the persistent cool West and hot mid-USA pattern that has not changed (significantly) since late last winter.

Well…it happened again the past 24 hours.  Yesterday we had a 7 day forecast that showed mainly clear skies and temps around 80 or so both days this weekend.  Now the ECMWF model is rushing an upper level trough right into the Pacific Northwest SATURDAY AFTERNOON!  That would mean clouds and showers late Saturday and into Sunday.  A 2nd wet weekend in the middle of July.  We get 2 runs of that model every day (a new one every 12 hours).  Now the GFS model comes in every 6 hours and has gradually moved towards the ECMWF the past day or so.  It has showers coming in Sunday evening or night with yucky/showery weather Monday.   Here at FOX12 we haven’t gone “whole hog ECMWF”, but the threat is there:

We could see showers as soon as Saturday evening, definitely by Monday, so likely only 1-2 days of noticeably warmer and drier weather at the end of the week (Friday and Saturday).  We may have to move the showers into Sunday as well; that 7 Day may yet go downhill further.

Believe me, I’m just as annoyed by the changing forecast as everyone else.  Many people make plans (months ahead of time) for the almost guaranteed dry weekends in later July and August.  At least we’re catching it 5-6 days ahead of time, much better than a Thursday or Friday change to a weekend forecast.

Chief Meteorologist Mark Nelsen