Search / 24 results found

from
to
  • Updated

Friday, July 30th, 12:30 P.M. 

After a warm start to the day, temps will soar close to 100° in the Portland metro area this afternoon/early evening. We are keeping an eye on some clouds and showers over the Cascades this afternoon. I can't rule out the chance for a brief shower or thunderstorm in the metro area or central valley this afternoon and evening.

High pressure will slowly back off over the weekend, but we will still have a southerly wind overhead. Thin smoke and high elevation clouds will be possible at times, and isolated storms could fire up during the afternoons & evenings along the Cascades and east of the mountains. Highs should trend back into mid 90s to upper 80s Saturday and Sunday.

High pressure will continue to inch away from the Pacific Northwest next week, resulting in cooler temperatures. Afternoon highs will slowly trend back down into the 80s, with overnight lows in the upper 50s and low 60s. 

  • Posted

Today was another very nice spring day.  Temperatures rose into the lower 70s west of the Cascades (except along the coastline).  This is what we typically see around Memorial Day, still a month away.

web_ORWA_HIGHS_Today_West

Every day except the first four has been at/above average as well.

Do you realize this is the driest month in Portland since last July?  That’s very dry for April.  It looks like we’ll see less than .20″ rain coming up with a weak system Wednesday evening and early Thursday.  That means we end up with less than 1.00″ for the month.  We haven’t seen that since 1966.

MarkDrySpells April

And what a change from the past few years…I remember the closed sports fields (standing water) in 2017 & 2018.

MarkDrySpells April2

The warm and dry April has taken quite a toll on the mountain snowpack, it’s melting much quicker than what we’d typically see.

Compare the April 1st “snow water equivalent” to the 28th.  Below 50% of average now in parts of southern Oregon and close to that 50% number in central Oregon.  These numbers will continue to drop the next 10 days since we see more warm weather next week

What’s ahead?  I see more of the same…drier and warmer than normal the next 7-10 days.  But that DOESN’T mean totally dry weather.

A strong upper-level ridge across the western USA is keeping weather systems very weak as they move by the Pacific Northwest.  This is tomorrow.

ecmwed

That ridge weakens quite a bit and a cool airmass attempts to move inland this weekend…this is Sunday.  Notice below normal heights across the entire northeastern Pacific, but it’s not directly over us.  Showery, but not crazy wet or cold.

ecm_sun3rd

But by the middle of next week the warm upper-level ridging returns, this time perhaps directly overhead

ecm_wed_6th

These maps are all from the European model ensembles, but other models are similar.  This COULD lead to our first 80 degree weather next week.  For sure we see another spell of mainly dry weather after this upcoming weekend.  This is 24 hour rainfall for each of the GFS ensemble members (one horizontal line per member) centered over the northern Willamette Valley.  You see the weekend showers, then very few members are forecasting significant rain next week.  Many are totally dry.

gfs-ensemble-all-KMMV-indiv_qpf_24-8075200

So, it’s been a nice spring but we could sure use a major week-long soaking sometime in May!  For now I don’t see any sign of that happening.

Chief Meteorologist Mark Nelsen

  • Posted

8pm Wednesday 

It’s been a very slow couple of weeks weather-wise; hard to find inspirational blog post material.

Putting that fork in winter was definitely the right thing to do two weeks back.  We have slipped back into a weather pattern similar to December with weather weather systems occasionally sliding into the Pacific Northwest.  Precipitation has been well below average across almost the entire western USA the past two weeks.  Portland has only seen .27″ in those two weeks!

hrap-all-nw-14day_percent_anom-3323200

February ended with near normal temps for us…nothing unusual there.  We’ve had a ridge of high pressure over us or just to our west the past couple of days.  Some nice weather has been the result!  By tomorrow that ridge is moving east and you can see a cold upper-level trough approaching.  This is the 500mb GEM (Canadian) ensemble average.  That’s the average of 21 difference ensemble members.

m500za_f024_bg_NA

One would think we have a cold/showery few days ahead (beyond tomorrow) with lots of mountain snow.  But all models show that trough splitting/stretching as it moves over the Western USA.  By Sunday a cold trough is well west of California and what’s left is moving over the Pacific Northwest.

gem_sundayam

That splitting means we get a weak cold front tomorrow night, then a few light showers Friday and Saturday.  Even though snow levels plummet down below 2,000′ by Saturday, there just isn’t much moisture to go around.  Expect only a few inches of snow in the Cascades and higher parts of the Coast range.  Yes, more slow weather.  Although on the bright side we MIGHT see some convection (brief heavy showers) Saturday…maybe.

That cold trough shifts east early next week, likely leaving us with mainly dry weather Sunday through Wednesday.  The same GEM ensembles for Wednesday the 11th

gem_wednesday11th

This gives us some pleasant, but not overly warm early/mid March weather.  All models then are in pretty good agreement another cold troughing “episode” shows up in about 10 days…the following weekend.  Saturday the 14th:

gem_saturday14th

Notice with ridging now, plus the first half of next week, that rainfall will remain below normal through the next 7-9 days.  The ensemble average rainfall from the ECMWF shows a half inch or so for the next week, and less than 2″ in the next two weeks.  That’s a bit drier than average, although clearly looking wetter that 2nd week.  The big story here is that I don’t see a long wet period ahead.

ecmwf-ensemble-KUAO-indiv_qpf-3323200

Temperatures will remain near (or even a bit below) average for early-mid March.  There’s no sign of a real intrusion of cold air in the ensemble averages.  But I don’t see any models going for extra-warm upper-level ridging either.  That means no 65-75 degree weather; which can happen this time of year.

To summarize

  1. Other than showers tomorrow night through Saturday evening, there isn’t much rain in the next 7 days.
  2. Near normal temps today/tomorrow turn cooler Friday through Sunday, then warm again early-middle of next week
  3. No sign of widespread frost west of the Cascades until at least Sunday night
  4. The increasing sun angle means even a 55-58 degree partly cloudy day feels warm for a few hours midday through afternoon!
  5. There’s no sign of a stormy March weather pattern ahead

By the way, are still hoping for snow?  I’m sayin’ there’s a chance!

Remember late March 2012?  A stalled front dropped steady/heavy precipitation right over the Willamette Valley.  4-6″ fell in the central/south Willamette Valley and even a few inches fell in the hilly areas around the metro area.  But measurable snow at the lowest elevations west of the Cascades in March IS rare.  Last year was exceptionally cold the first 10 days of the month.  That was mainly due to extensive snow cover left to our north and east from the record cold February.

Portland Snow Last Few Times In March2

Portland Snow Last Few Times In March2

More likely is a temperature getting close to 70 at some point this month!

March Warmest Temp

Chief Meteorologist Mark Nelsen

  • Posted

9:00pm Thursday…

These first 10 days of October have been the coldest in Portland since the early 1970s!  Not only did we see a record low temperature of 33 in Portland this morning; but it was the earliest 33 degree reading since 1985!  Take a look at some of the lows around the metro area

PDX Observed Low Today

You’ll notice that some of us did not have a “first frost”.  Much of East Portland saw enough of an easterly breeze to keep temperatures up around 40 degrees.  A northerly breeze kept some Willamette Valley locations a bit on the “warm” side as well.  Now check out the frigid temps east of the Cascades…amazing for early October.  Single digits at Burns.

Todays Observed Lows OrWa 2017

That 13 at La Grande is the coldest October temp in 13 years!  And it happened by the 10th of the month.  The last time Redmond was this cold (13) in the first half of October was 50 years ago!  Redmond has been all the way down to zero and even a little below in October, but it has always been in the last few days of the month.  This was a very rare event, and I think it’s VERY interesting that we’ve seen something similar occur twice now this fall.  The same weather setup a month from now would give us a blast of cold arctic air.

What’s ahead?  More of the same tomorrow, except a stronger east wind blowing through the west end of the Columbia River Gorge and east metro area.  Gusts have been in the 40-50 mph rage.  Expect those gusts to bump up to around 50-60 there tomorrow and 25-35 mph in east metro.  Of course we’ll see sunshine all day too.

This Weekend

Definitely a “meh” weekend ahead.  A very weak system dies overhead late Saturday and Sunday.  Lots of clouds but very little rain.  We lose the east wind Saturday.  At best we could see .10″ rainfall total by late Sunday.  Monday looks dry too.

There are strong hints that we’ll see our first soaking rain of October the 2nd half of next week.  See the ECMWF model forecast of 24 hour rainfall.  Each thin horizontal line is one of the 51 ensemble members on the top half.  The bottom half shows the average of all ensemble members.  Good agreement that next Wednesday-Saturday will be wet, maybe not excessively so, but back to normal.  Expect lots more cloud cover too.

ecmwf-KPDX-indiv_qpf_24-0708800

All the more reason to enjoy this fantastic sunny/cool October weather.  Have a great weekend!

Chief Meteorologist Mark Nelsen