Fire Smoke & Long Range Outlook

September 15, 2014

The first large forest fire close to the metro area in at least 20 years sent a lot of smoke our way the past few days.  The 36 Pit fire continues to burn just a few miles southeast of Estacada this evening; luckily winds have been light so far.

Air quality was actually surprisingly good in the Portland Metro area, in the GOOD category all day.  That’s because we had a light east and north wind in our area, sending most of the smoke south into the central and southern Willamette Valley.  Salem’s air quality was pretty bad in the afternoon; visibility was down to just over 2 miles at one point!

The good news is that a marine push (cooler ocean air) has developed this evening and the westerly wind is already pushing the smoke out of the valleys…slowly.  You can see what happened at Salem as the westerly wind kicked in…dramatic improvement in the air quality:

MarkAirQuality_Salem

Tomorrow should be much better as the light westerly flow pushes just about all the smoke up into the Cascades.

This was a relatively close call for our area.  The closest we’ve seen a 1,000 acre or larger fire is way up on Mt. Hood or just east of Hood River the past 20 years.  We haven’t seen that much acreage burning within 30 miles of downtown Portland, although I have a feeling the Multnomah Falls Fire in 1991 covered a lot of ground/acres in a short period of time.  I moved to the metro area just a few weeks after that one.

The long range outlook still looks warmer than average for much of the next two weeks (the rest of September).  Here are the two ensemble charts from the 12z ECMWF:

tseries_850t_000-360_Portland

and the 18z GFS:

tseries_850t_000-384_Portland

Notice the ECMWF  is all over the place after next weekend’s warmup, but seems to be near/below average.  The 18z GFS is crazy warm with two more “hot spells” before we end the month.  It’s always best to follow the average of the ensembles (red line), which is still much warmer than normal.  The monthly ECMWF run last night showed ridging holding much of the next two weeks, then the ridge backing offshore into it’s preferred position over the past year and a half.  That’s out in the Gulf of Alaska.  That would cool us dramatically, but not a real wet pattern into early October.

500za_week1_bg_NA

500za_week2_bg_NA

500za_week3_bg_NA

500za_week4_bg_NA

We haven’t seen a widespread soaking in almost two months now; the last wet days were the third week of July.  And I don’t see a good soaking in the next 10 days at least.  We’ll see a few hundredths Thursday or early Friday, but that’s it and it won’t do your garden/lawn/trees any good.  Keep watering!

With today’s 90 degree temperature, we’ve now seen 20 days at/above 90 degrees this warm season, it’s been hot!

Chief Meteorologist Mark Nelsen