Vacation Time

June 29, 2019

I’m on vacation for the first week of July.  Traveling through British Columbia with my son mountain biking.  Back at work Sunday the  7th.  Until then, enjoy this nice view of Osoyoos, BC as a thunderstorm was developing overhead Friday the 28th.   E704650E-3866-4699-A46F-FD580943ED7E.jpeg


Powerful Thunderstorms Move Through Metro Area Wednesday Evening

June 26, 2019

10pm Wednesday…

Whew!  That was exciting wasn’t it?  Between 5-8pm thunderstorms moved through the metro area.  Heaviest rain was right up along the east side of I-205 in east metro.

LateJuneT'Storm_26th

Officially PDX only saw 0.10″, but some of you went right on over the one inch mark

Rain Totals Metro Area

One video we’ve been showing on FOX12 shows hail accumulating many inches deep along the side of a house as well.  By the way, earlier today a severe thunderstorm covered Hwy 26 with hail near Zigzag

photo hail rhody

Back to the metro area…the line of thunderstorms pushed a large swath of “outflow” wind north and east ahead of it.  Check out the peak gusts!  Similar to a weak winter windstorm event

Wind Peak Gusts Text Panel

This put 26,000 PGE customers out of power (including my home) and 5,000 in Clark county.  That’s one of the largest numbers I’ve seen for thunderstorms in the metro area.  The combo of lightning + wind likely led to the large number of outages.  Many thunderstorm events in our area don’t include the strong wind.

Note there was no Severe Thunderstorm Warning as the storms rolled through.  That’s because there is a specific definition:

  • Large hail, 1″ (quarter size) or larger
  • Damaging wind gusts 58+ mph

So yes, a very exciting thunderstorm but it wasn’t technically considered “severe”.

Looking ahead, tomorrow we’ll be under the influence of the upper-level low offshore.  That means another round of showers/thunderstorms.  But they shouldn’t be as “organized”.  By that I mean they should be more like typical spring thunderstorms with just a few rumbles or flashes of lightning with the showers.  Strong wind is far less likely.

Chief Meteorologist Mark Nelsen

 

 


Much Needed Rain On The Way Next 4 Days

June 24, 2019

6pm Monday…

June has been very dry across the region.  Only .23″ in Portland so far this month, with just 6 days to go.

Month Climate Rain Calendar Saturday Start

This is our 5th consecutive drier-than-average June and most of the Pacific Northwest has been dry.

precipanomaly

But I see some hefty showers Wednesday-Friday, especially west of and over the Cascades.  What’s up?

A cool upper-level low is dropping down the Canadian coastline right now, and it arrives offshore by Wednesday morning.

wrf_500_wed

A couple points.  First, this isn’t quite as cold as the low that brought Timberline snow this past weekend.  The other is that as it approaches the upper-level flow turns southerly plus the airmass moistens up.  That begins tomorrow afternoon.  There are hints that some showers and/or thundershowers pop up across the region.  I think that’s most likely over the Cascades but can’t rule out a brief shower over the western valleys for your Tuesday afternoon.  Just keep an eye on the radar and sky tomorrow afternoon.

Far more likely is a three day period with widespread showers and embedded thunderstorms Wednesday through Friday.  By Thursday morning that upper-low is directly overhead = pretty good lifting.

wrf_500_thu_pm

This pattern in June is typically a very good rain producer.   By the time it leaves the area Saturday, the “new and improved” GFS (American) model gives us a nice soaking.  Maybe 1/2″ or more in the valleys and over an inch in the mountains.  Even a little in Eastern Oregon with thunderstorms.

gfs_totalprecip

The ECMWF is somewhat drier, sending less than 0.25″ into most western valleys of Oregon.

ecmwf_totalprecip

Both models shut off just about all the showers after Friday once the low moves to the north.  You can see it on the 24hr rainfall forecast from ECMWF ensembles.  Just about all the “rain action” is going to be Wednesday through early Saturday.

ecmwf-KPDX-indiv_qpf_24-1377600

To summarize

  1. Expect a cool, wet, & breezy period Wednesday through Friday
  2. Water sports won’t be pleasant Wednesday-Saturday…chilly!
  3. Thunderstorms are possible any of those days; could be a situation where you get 1/2″ of rain at your home and 5 miles away it’s sunny at the same time.  Think spring weather.
  4. At best we’ll see up to 1″ of rain in a few lowland locations by the time July rolls around a week from now.  At worst, just a quarter inch of rain to wet only the top of the soil.
  5. Regardless, this puts the beginning of fire season off for another week or two.  No major fire worries until the 1st or 2nd week of July.

Chief Meteorologist Mark Nelsen


Slow Start To Fire Season 2019

June 20, 2019

9pm Thursday…

Have you noticed one thing is missing so far this season?  Hardly any talk of fires or smoke in the air.  That’s because fire activity UP TO THIS POINT has been lower than any year since at least 2009 here in the USA.  Check out acreage burned so far across the entire country.

Fire USA Summer Stats

That’s only a quarter of the acreage burned compared to this date in the previous 3 seasons.  Most likely that’s due to a late/cold spring from the Rockies westward into California.  Temperature departure the past 30 days

cdas-west-t2m_f_anom_30day_back-1053600

and of course the very late wet conditions everywhere south and east of Oregon have put off the beginning of fire season

hrap-nw-30day_percent_anom-0038400

Only western Oregon and Washington have been drier than normal late spring and very early this summer.  You can see that in the “1,000 hr fuel moisture” for the western slopes of the northern Oregon Cascades.  The black line is this year, light gray is average, and red is record driest.  We’re tracking near to a little drier than average for those larger fuels in this part of the forest.

Capture.PNG

What we haven’t seen yet is any sort of warm/hot weather lined up with dry lightning.  That’s what gets the big fires going.  No sign of that through the rest of June as we are now in a cooler and wetter than normal pattern.  I would expect fuels to be wetter by the time we get to July 1st.

Now I remember many years where it’s all quiet through mid-July and then all hell breaks loose with one lightning outbreak in late July or early August.  So obviously a slow early season doesn’t mean much for later this summer.   We had another relatively light year for lightning, nothing like the crazy 2012-2016 summers!  Chart from USFS

Capture2

You probably remember the “perfect storm” for August & early September smoke the past two summers?  Big BC fires, big and persistent SW Oregon fires, and then of course the close-by Eagle Creek fire in 2017.  It’s unlikely we’ll see that convergence of fire smoke again this year unless we get another scorching hot summer plus a ramp-up of lightning action compared to last year.  We’ll see.

At this point it appears we’ll see some sort of warm up beginning somewhere around July 1st.  Models say the upper-level troughing goes away about that time.   So enjoy the cool late June weather (not my tomatoes) and cross those fingers for a slow fire season and not much smoke!

Chief Meteorologist Mark Nelsen

 

 


Warm & Dry June Turns Cooler Next 10 Days

June 18, 2019

7pm Tuesday…

Today our weather returned to normal temperature-wise.  That’s follows 9 days of  a mid-summer weather pattern; temps mainly in the 80s & 90s.

High Temp Last 13 Days

Of course this means June is tracking very warm…

Month Climate Temps Calendar

and quite dry.  Only two days with measurable rain through the 18th, that could continue all the way through the 22nd or 23rd I suppose.

Month Climate Rain Calendar Saturday Start

But the last 10-12 days of June sure look cooler.  Or maybe more accurate…

Typical June Weather is On The Way

What’s changing?  More cloud cover and cooler temps is the general story.  For now we have higher than normal upper-level heights over the Pacific Northwest

ecmwf-namer-z500_anom-0859200

But quite a change Thursday as a cold trough of low pressure drops in.

ecmwf-namer-z500_anom-1032000

That’s followed by a 2nd pool of chilly air sitting just offshore or right over us much of next week, starting Tuesday.  These charts are from the ECMWF model for Tuesday and Friday NEXT week.

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It’s not like we’re going to see endless days of rain and highs in the 60s, but expect noticeably cooler weather next week with some showers at times.

Two Big Questions

  1. Will it be dry this weekend?  YES, FOR MOST OF US.  We’ll be in-between that cold system Thursday and the one early next week.  FRIDAY AND SATURDAY WILL BE NICER THAN SUNDAY.
  2. How much rain could we see in the next 10 days?  Probably not enough for you to shut off irrigation for crops and lawns.  Maybe enough to back off on your garden veggie watering around the middle/end of next week.  Until that time (through this weekend), I don’t see any significant rain.

Here’s the 10 day total rain forecast from the operational runs of the ECMWF & GFS models.  Both imply 1/2″ or less in most lowland areas (where most of us live west of the Cascades).  Of course more in the mountains.

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Checking the ECMWF ensembles for Salem (middle of the Willamette Valley), the average is around 1/2″ as well.  That’s in green; bottom half of chart.  Notice a few members (top half of chart) are wetter, but some are drier…thus the “average”.

ecmwf-KSLE-indiv_qpf-0859200

To Summarize

  • The next 7-10 days will be near normal to cooler than normal for late June
  • Expect some showers at times, mainly AFTER next Monday
  • No sign of hot weather returning through the end of June

Chief Meteorologist Mark Nelsen

 


Midweek Scorcher Delivers

June 12, 2019

6pm Wednesday…

Whew!  What a scorcher.  98 at this hour in Portland ,which is also the high temp for the day so far.  Tomorrow will be so much nicer since we get a major marine push.  A good 15 degree drop.

I’m at a weather conference in California for a couple more days.  Try to stay cool tonight!

 


July Weather Next 10 Days; Includes A Midweek Scorcher

June 9, 2019

9pm Sunday…

Quite a change the last few days.  Most of us were in the 50s and lower 60s with showers/thunderstorms Friday.  Yesterday was a clouds to sunshine day; good news for for Grand Floral Parade day.  Temps rose 5-10 degrees. Then another 10 degrees warming today brought temps well above average once again:

High Temp Last 13 Days

The big picture says we’re going to be quite warm for the next 10 days or so.  From the ECMWF model you see upper-level heights (ridging in this case) above average through the next 15 days.  The three images represent Days 1-5, 6-11, and 11-15.  That takes us through the first three weeks of June.

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Looks to me like it’s going to be our 7th June with average to above average temps.  Those three cold Junes 2010-2012 seem like a long time ago now.

June Month In Review

What about rain?  Little or none in the next 10 days.  Each line on the top half of this chart shows one ensemble member.  Quite a few show less than .10″ in the next 15 days!  This may be the beginning of the dry season.  If so, it’s going to be a long one again…

ecmwf-KPDX-indiv_qpf_24-0081600

And well below average rain the next 15-16 days forecast by both ECMWF and GFS ensemble systems.  Wet weather continues across the saturated central/eastern USA.

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In the short term, tomorrow should be similar to today, but up a few degrees.  Then the big change is a switch to easterly wind Tuesday through Wednesday midday.   You can see it circled on the WRF-GFS cross-section over Portland.  The 11/12 along bottom axis = June 11th at 5am, and 12/12 = June 12th at 5am.

Capture

 

At the same time 850mb temps rise up to +21 or +22 over Salem.  According to my chart, based on past similar setups, we should see high temps both days between 95-100 degrees.  Cooling onshore flow doesn’t arrive until Wednesday evening after peak heating.  Whew!

Luckily a quick cooling overhead along with low-level onshore flow should drop us into the 80s Thursday and then down around 80 Friday.  This won’t be a many days-long heatwave.  Still, daily record highs will probably fall both Tuesday/Wednesday

Mark Hot 3 Day PDX Forecast2

Stay cool!  Chief Meteorologist Mark Nelsen