A Busier Day: Tornado, Funnel Cloud, & Cat 5 Hurricane

September 19, 2017

10pm Tuesday…

I thought yesterday was busy, but today was just plain crazy.  Back in the old days (20 years ago) I might have appeared on 1-3 TV newcasts per day, maybe with a radio hit or two as well.

Today I was in 6 newscasts, plus regularly tweeting, facebooking, & keeping up on other internet activities.  It can get crazy!

So today we had our 2nd Oregon tornado of the year (first was in central Oregon earlier in the year).  This one was east of Lacomb, which is well east of Lebanon.  Way out in rural Linn County.  It was a classic westside “barn-buster”;  No deaths, injuries, or damage to homes.  Just 4 barns damaged along with some trees.  An EF-0 is the weakest tornado one can get.  Thanks to the Portland NWS for all the hard work doing their storm survey.  Here are the results:


Here’s how it compares to some other recent tornadoes in our area

Tornado Categories

We received two different videos of funnel clouds both there and near Molalla.  So an exciting day.  I saw nothing on radar that showed much wind shear or rotation with the Lebanon storm.  Part of the reason (other than it was such a weak event) is that Lebanon is a long way from the Portland radar.  The lowest elevation radar beam is up around 9,000′ or even a little higher by the time it’s over Lebanon; that means it’s quite easy to miss rotation in the lower parts of the cloud.

Tornado Why We Cant See Eugene

Our very wet week continues, take a look at rain totals so far (since Sunday PM) in the Cascades…apparently models were right on showing 5-8″ in spots in the North Oregon Cascades

Mark Rain Cascades East Metro Today

Mark Rain Cascades East Metro Today2

And the rain has made it all the way down into south Cascades…very good.

Expect one more soaker tonight and then showers should taper off a little Wednesday afternoon.  Thursday will just be a light shower day.

By the way, it’s beautiful but deadly and dangerous…Category 5 Hurricane Maria is directly over the west end of St. Croix in the U.S. Virgin Islands right now.


Wow, imagine a 175 mph wind.  Remember those gusts we feel up at Vista House in winter are maybe 100-120 at most.  Think what that storm is doing to the island right now.  It’s headed for Puerto Rico Wednesday.

Chief Meteorologist Mark Nelsen

A Busy Weather Day: Thunderstorms & A Waterspout

September 18, 2017


As expected, thunderstorms and hail showers are moving across the western part of Oregon & SW Washington too.  That’s due to a chilly airmass overhead but we still have relatively warm temperatures down here where we all live.  That means lots of rising motion in the atmosphere = thunderstorms.

Note the 1st fall snow up in the Cascades…Timberline Lodge this morning:


One thunderstorm produced a waterspout just offshore of Happy Camp (between Netarts Bay & Oceanside).  IF that would have moved onshore, it would be a tornado.  Remember Manzanita last October?


Of course many of you are seeing thunder and hail right now as a cluster of action moves over the Portland Metro area.  This will continue through the afternoon, of course interspersed with sunbreaks too.  Classic spring, or fall, weather.  Enjoy the change and by the way, enjoy the fresh air!  Particulates in our air this morning were so few and far between they could barely be measure…all of 8 on the AQI:


Stay safe this afternoon while driving through downpours, we’re out of practice with our rainy driving skills…


That’s the 12:40pm radar image here in the metro area, looks like Sherwood and Newberg getting the action, but the cells will continue moving to the east/northeast.

Chief Meteorologist Mark Nelsen

The Rain Is Back!

September 17, 2017

11pm Sunday

The rain is back this evening, although we’ve had less than 1/10th of an inch in the city.  Much more has fallen since mid-afternoon out over the Cascades, including the western portion of the Eagle Creek Fire:

There is lots more rain to come, as I’ve been mentioning for the past week.  Our RPM model is estimating 1-2″ by late Wednesday in the western valleys and 3-5″ over the Cascade crest and down into the western foothills.

Even the dry north-central part of Oregon will get enough to settle the dust.  This may be our wettest week since March; for sure the wettest since May.

Enjoy all your indoor pursuits the next few days!

Chief Meteorologist Mark Nelsen

September: Record Hot 1st Half but October Weather Next Week

September 15, 2017

10am Friday

I just checked the numbers and sure enough, you just survived the hottest start to September on record here in Portland…


But the payback next week is going to be rough, we’re going straight from July weather to October in just a couple of days.  Those first two weeks of the month blew away any other early September period on record.  The average high was 85 degrees!  Plus we set 5 record warm lows and had the warmest nights ever recorded in Portland in the month of September.  You can see the entire West has been hot, but it’s balanced out by a chilly eastern USA.  This month is a “perfectly normal” month when averaged across the country


And of course this follows the hottest August on record all along the West Coast.


Now we’re about to see the most dramatic change we can possibly get this time of year.  Remember we’ve had a hot upper-level ridge along the West Coast most of the time since late July.  But beginning Sunday that ridge develops way offshore, in the Gulf of Alaska. Look at the 500 millibar height deviation for midweek.  If it was winter that could give us an arctic outbreak with cold/snow likely:


Of course it’s not winter, but this means we’ll go from record warm to near record chilly!  The best part about this pattern change?

I EXPECT FIRE SEASON TO AN EARLY END NEXT WEEK ALL ACROSS THE REGION.  The Eagle Creek Fire is going to be out a week from now if our models are correct.  Take a look at the ECMWF rainfall and temperature forecast for the Portland area for the next 10 days


We still expect rain to arrive Sunday afternoon (light rain at first) and then a big soaking Monday and Tuesday as cold showers/thundershowers/hail showers arrive.  Also look at those chilly temps!  High temperatures only in the 60s, maybe even a couple of days where we spend most of our day in the 50s!  That’s a huge change.  Now remember this is just one run of one model, but they are all showing the same thing.  Here is a peek at the ECMWF ensembles; 51 members of the same model showing 24 hour rainfall


The first half of next week is wet, with far smaller accumulations in the rain bucket beyond next Thursday.

But there’s more!  Just about all the big fires are burning in the Cascades and look at how much rain could fall Sunday through next Thursday…first the ECMWF:


Widespread 2-5″ rain totals on the west slopes and crest of the mountains.  No fire will survive that deluge…excellent news!  Note the valley gets around an inch or so.  Then the GFS model, which has some terrain issues so don’t read too much into all that rain in the metro area:


Same idea, 2-5″ (or more!) in the mountains and around an inch in the driest part of the valleys.

To summarize…



Enjoy these next two days, although light easterly wind means fire smoke will be moving around the area as seen in this AM pic from Andrew Mork:


Sunday’s rain should put an end to our smokiest summer in memory!

Chief Meteorologist Mark Nelsen


First Look at the Gorge Fire

September 13, 2017

Here’s a first (& detailed!) look at how the Gorge survived the Eagle Creek Fire. I’m surprised how much green is still there. It basically looks the same with some burned spots. Great stuff by Tom Kloster

WyEast Blog

GorgeFire01 Eagle Creek Fire during the initial, explosive phase (US Forest Service)

Officially the Eagle Creek Fire in the Columbia River Gorge is still fully involved, now at 35,000 acres and just 10 percent contained by firefighters. Rain in the forecast for the coming week suggests that the fire will continue to slow as October approaches, and our attention will turn toward the changes that fire has once again brought to the Gorge.

The Gorge is a second home for many of us, and in some ways the fire was akin to watching our “home” burn. But that’s a human perspective that we should resist over the long term if we care about the ecological health of the Gorge. Fire is as natural and necessary as the rain in this amazing place, though that’s a truth that we have been conditioned to resist. I’ll post more on that subject in a…

View original post 1,487 more words

91 in Portland Today; First Soaker of Autumn On The Way Too

September 11, 2017

7pm Monday

Today was warmer than expected; we all made it into the lower 90s in the metro area.

PDX Observed High Today

Some very good news; easterly wind was light as expected and has now switched back to westerly in the Gorge already this evening.  That means all of you (and me) in Level 3 evacuation areas west of Cascade Locks can relax…there’s nothing weatherwise that would cause the fire to take off again in the next week.  Fire lines passed the “East Wind Test” today thanks to all the firefighters who’ve been working on creating containment lines during the cool weather the past 5 days.  Hopefully evacuation levels will be lowered tomorrow.

Back to the heat…notice how many 90+ days this summer in Portland:

MAY: 1

That is the 2nd time we’ve had 24 days at/above 90 degrees in Portland, it happened in 2009 as well.  Only in 2015 have we seen more of these 90 degree scorchers.

90 Degree Days Summer Heat

I think it’s very possible this was our last 90 degree day of the season.  That’s because for the first time since July I see a weather pattern that doesn’t feature warm/hot upper-level ridging nearby.  That’s for the next 10-14 days.

Models do bring one weak disturbance through our area later Wednesday and Thursday, but it’s coming down from the north so expect dry weather.

Jet Stream Forecast 2017

That dry Canadian air moving south means dewpoints (amount of moisture in the air) drop into the 40s Wednesday-Friday.  That combined with long September nights means we’ll have our first “chilly” nights of fall with widespread 40s in the metro area.  But the benefit will be plenty of sun during the day and comfortable afternoon temperatures in the 70s.  Some would say Wednesday through Friday will be perfect early Fall days.  But check out the ECMWF ensemble temperature forecast for Portland for the next 15 days…sure looks different doesn’t it?  No spell of “hot” or even very warm weather.


Note those days in the 60s next week.  That cool spell will be accompanied by our first soaking of the Fall.  There is quite good agreement that a cold upper-level trough will drop in over us Sunday-Tuesday next week.

Jet Stream Forecast 2017b

The ECMWF is painting a large area of 2″+ rain in the Cascades during that time with maybe up to 1″ in the valleys.  This will be our first soaking in 3 months (since mid June).

ECMWF Precipitation Accumulation

If this happens, it could be a season-ending event for some fires in the mountains.  Fires don’t burn well with 2″ of rain plus temperatures in the 40s & 50s…brrr!

So enjoy the pleasant weather the rest of the week and plan on finishing any outdoor projects by Saturday…anything left outside could get very wet Sunday and beyond.

Chief Meteorologist Mark Nelsen


Eagle Creek Fire Weather Update: No Strong East Wind Expected

September 9, 2017

8pm Saturday…

I’ve been receiving a few emails and text messages from friends and viewers the past 24 hours.  Most of them (for good reason) want to know “when the dry and gusty east wind is coming back”.  There is good news again this evening; I DON’T EXPECT A RETURN OF A STRONG & DRY EASTERLY WIND, LIKE WE SAW THIS PAST MONDAY, FOR AT LEAST THE NEXT WEEK.  There is going to be some wind early in the week, but nothing like what almost became a firestorm Monday night.

Here’s where things stand as of Saturday evening:

  1. The fire has only grown on the southern and eastern end the past few days because we’ve been under a westerly wind pattern (as expected).
  2. Luckily this pattern has been quite cool (compared to the past 5 weeks) and mainly cloudy.  At 1,800′ there is a weather station at a home on the west side of Larch Mountain.  After days and days of temps in the 80s, the past 3 have all stayed at/below 70 degrees with relative humidity often up in the 60-100% range; that’ll bring fire activity way down.
  3. The western end of the fire is just smoldering and creeping with very little smoke seen west of Angel’s Rest.
  4. There is concern that a renewed hot/dry easterly wind could allow the fire to take off again and head to the west.  As a result firefighters plan to hold the fire east of Palmer Mill Road which I’m also told happens to be the fire line where the 1991 Falls fire was stopped.  They have been working there fixing the road and cutting lots of brush/trees.  Interesting that it was the same weather pattern 26 years later; and the same place the fire petered out last time.

Here’s a map of the eastern half of the fire, click for a larger view:

and the western end, closer to the metro area:

The red is the fire perimeter, which pretty much hasn’t changed at the west end since Tuesday when the east wind died.  I’ve added the blue line, which is Palmer Mill Road.  Now let’s talk weather.  The yellow area is the “east wind zone” on the Oregon side during just about all east wind events; winter AND summer.  Easterly wind, which is actually northeast wind due to orientation of the river, sticks quite close to the Columbia River until it gets around Rooster Rock State Park; always less than a mile or so from the river.  At that point the Columbia is about to enter the Willamette Valley and the hills become much lower (less than 2,000′).  The wind spreads much farther from the river, maybe 3 miles south of the river once it gets to Troutdale.  The homes/properties south of the yellow hatched area rarely get east wind (and didn’t last Monday).  These are great places to live if you don’t like that cold winter wind and also quite a bit safer since a fire wouldn’t come roaring in on wind.

So the big question is…“will we get a bunch of strong wind in the next few days?”  I think that’s unlikely.  Models all bring upper-level ridging (hot high pressure) overhead later Sunday through Tuesday, then that’s followed by more cool upper-level troughing toward the middle of next week.  Folks it appears fall weather is arriving.  That means brief warm periods followed by cooler weather as we’ve seen the past few days.   On Monday and Tuesday we’ll get well into the 80s, even a 90 is possible, so summer wants to have one last gasp.  Yet the pattern is not conducive to a gusty easterly wind coming down the Gorge due to it being a “flat” upper-level ridge.  Take a look at the cross-section over Troutdale for the next 3 days.

Time goes from RIGHT TO LEFT; right side was 5am this morning, 10/12=Sunday AM, 11/12=Monday AM, 12/12=Tuesday AM.  Wind flags show the wind direction.  Colors are relative humidity.  The “850” horizontal line partway up is around 5,000′ elevation and you can see the surface (where we live) below.  Note the high humidity through Sunday morning then we dry out quickly (afternoon sunshine!).  But wind flow is still westerly (onshore flow).  Monday morning through early Tuesday we go into an east wind pattern.  Yet the wind flow is not very strong.  This would give gusts maybe 20-30 mph around the ridges at the west end of the Gorge, but not the big 40-50 mph gusts we were seeing up there last Monday.  Still 20-30 mph is enough to keep a fire moving along the ridges.  I’m not a trained fire weather forecaster, but I would assume unburned areas of trees could ignite again under these conditions.  But there’s no reason to think with a weaker wind in the exact same location, that the fire would spread farther than last Monday.  It’ll still “run out” of that dry east wind in the same spots.  Hopefully that makes a bit of sense.

To summarize, I think we’ll get through Monday and Tuesday without a major increase in fire acreage.  But, for good reason, I’m guessing emergency managers will prefer the Level 3 people remain out of the area until after this east wind period passes by Tuesday evening.  We’ll find out the next 2 days at their press conferences.

As for rain, we’re getting some showers for the 2nd time this week this evening.  It’s just a few light showers, but it’ll wet the dust again.  Any rain is good.  At this point the next chance for a soaking appears to be about a week from now.  The ECMWF ensembles show some rain late next Sunday or Monday, kicking off a cooler/wetter period.  It’s possible that Tuesday will really be the last of our summer weather.  Enjoy the sun Monday and Tuesday!


Here is some more good news…great pics from Tessie Adams with Corbett Fire (Multco District #14) taken Friday:

Multnomah Falls area looks pretty good!  A lot of the fire must have run beneath the tree canopy in some spots and then torched from one crown to another in others.

As in this pic taken alongside the old Scenic Highway, note the mainly green trees above and burned brush below

Chief Meteorologist Mark Nelsen