80 Degree Record Tied

September 28, 2015

We hit 81 in Portland today, which ties the old record for most 80 degree days in one season.  During the blazing hot summer of 1967 we had 84 days at/above 80 degrees.  As of today we’ve seen 84.

MarkHeatwaveStudio_80DegreeTemps

One difference this year compared to 1967 is that the heat arrived much earlier.  That year it was July/August, this year it was mainly June/July.  August was warmer than normal but not a crazy hot month.  September will end up slightly below average.

Note we’ve seen DOUBLE the number of 80 degree days as in the cool summers of 2010-2011.

Tomorrow we should hit 80 again but that might be it for the season.  The pattern still looks ridgy the first part of October, but that doesn’t mean we’ll hit 80 again.

Chief Meteorologist Mark Nelsen


ECMWF Monthly Run

September 28, 2015

Maps ahead for the real hardcore weather geeks only…

Interesting turn of events with the ECMWF over the past few days.  It’s now showing ridging returning earlier than expected. In the monthly run one week ago it was showing ridging after the first week or so of October.  Now it’s pretty much from here on out through the month of October.  Here are the 4 weekly maps showing upper-level ridging hanging around the region for the next 4 weeks.

500za_week1_bg_NA

500za_week2_bg_NA

500za_week3_bg_NA

500za_week4_bg_NA

I can’t show you the maps (legal issue), but the total precipitation (ensemble average) is only around 2″ in the next 32 days here in the valley.  The control run (higher res) shows 3-4″ during that period.  Surface temperatures are above normal, when all 32 days are averaged, in both control and ensembles.

What a pain to forecast this coming weekend.  The GFS builds a ridge quite close to us, but the ECMWF and GEM (Canadian) both bring a cold trough down over us Saturday.  It leaves quickly, but these models would imply 60-65 degrees on Saturday with a few showers, whereas the GFS says about 85 and sunny with strong easterly wind.  I went in the middle for now.  You can sure see the disagreement even among just the ECMWF ensembles:

tseries_850t_000-360_Portland

Chief Meteorologist Mark Nelsen