Halloween Forecast and November Weather Action

October 26, 2011

The forecast isn’t looking so bad for this weekend; that’s because our dull weather pattern continues through about the middle of next week (the next 6-7 days).  One weak weather system comes through here Friday, and another late Sunday.  That leaves Saturday and most of Sunday dry, and then just a few leftover showers on Monday.  By Monday evening we should be clearing out; the little tots might actually have dry weather!  I’ll think I’ll join my kids on Monday too…should I go as a Gangsta’ like my son?  Probably not; doesn’t seem to quite fit.

Moving on…tomorrow DOES look like a nice day to get work done outside (again!).  A foggy start, then sun in the afternoon.

I mentioned a change coming up next week.  Models seem to be keying in on stronger troughing in the Eastern Pacific and Western USA.  This is WAY out there, but in the 7-14 day period several troughs come crashing down into our region.  They each contain colder air and periods of rain.  It’s pretty obvious on these two charts:

They are the long range ensemble forecasts from the 12z ECMWF and 18z GFS runs.  Two things stick out on both.  After about November 2nd, 850mb temps (around 5,000′) drop below average for most or all of the rest of the model runs.  That implies cooler than average temperatures, and most precipitation would fall as snow at/above pass elevations in the Cascades.  The blue line is the “operational” run, the red line is the average of all the ensemble members.  The green is average.  The other item I noticed is the GFS (at least the 18z) operational is just about the coolest of all the ensemble members.  So it may be a bit cold…we’ll see.

So prepare for a change next week, but it appears we’ll end up with a drier than average October.

Chief Meteorologist Mark Nelsen