Fire Danger Lowers Western Gorge, Showers For Some Thursday

September 6, 2017

10pm Wednesday

Good news continued for a 2nd day in the Columbia River Gorge as fire growth was minimal in rural/populated areas today.  After some IR mapping, officials tell us the fire is over 30,000 acres now. Wind has reversed as expected and now we have the usual warm season westerly wind blowing in the central/eastern Gorge.  West wind is always light west of Multnomah Falls.  This will be the wind direction through at least Sunday, possibly even into early next week.

Fire Gorge East Wind

On top of that, scattered showers will develop tomorrow afternoon/evening.  There’s even a small chance of a downpour over some part of the fire.  Then Friday we’ll see strong onshore flow, clouds, high humidity, and temperatures in the 60s up in the hills around the fire. This will bring it to a crawl as well.

To summarize:

  1. Fire growth should be minimal or non-existent in the areas around homes in eastern Multnomah County (Corbett to Bridal Veil) from now through the weekend.
  2. Westerly wind could spread the fire to the east in Hood River County, possibly gobbling up a significant amount of acreage in the uninhabited forest south and southeast of Cascade Locks.
  3. There is no sign of a strong east wind event in the next 7 days.  A few models show a typical light easterly wind late next Monday or Tuesday.  But others do not.

 

So let’s talk about weather.  A deep layer of moist air will be moving overhead these next two days.

Satellite Surface

It’s coming from the southeast between an upper-level low and the hot high pressure to the east.  This is one of our favored “thunderstorm patterns”.  In fact models show plenty of CAPE, low Lifted Index, & high Precipitable Water.  The combo of these three tells me we are going to see some sort of thunder action in the next 24 hours.  As a result I think there will be a few flashes in Western Oregon tonight, and likely quite a few more tomorrow afternoon & evening.  One more thing to point out.  There will be a ton of moisture in the atmosphere overhead which means those thunderstorms could be quite wet.  It’s possibly a few of us could get our first real dumping of rain since mid June.  But in this pattern the placement of those downpours can’t be forecast.  One neighborhood will get a soaking while 5 miles away it may be all dry.

Beyond tomorrow we’ll have strong onshore flow Friday for cloud cover that may linger much of the day west of the Cascades.  A weak system moves through Western Washington Saturday which should keep us at least partly cloudy down here.  That will keep temperatures well down in the 70s for another day.  Then it’s back to high pressure and warmer temperatures Sunday and beyond.

Chief Meteorologist Mark Nelsen