The Southern Oregon Coast Hits 79F as a Super-Inversion Develops over the Northwest

Update at the end!

High pressure and a super-inversion have developed over the Northwest, and jaw-dropping weather contrasts have developed--both in the horizontal and the vertical.

For example, yesterday (Saturday) temperatures zoomed up to near 80F on the southern Oregon coast, with 79F at Brookings, Oregon (see yesterday's max temps, below, click on the image to expand).  The forecasts were right.


At the same time, temperatures were in the 40s in eastern Oregon and BELOW FREEZING in large sections of the Columbia Basin of Washington (see Saturday's high temps below). 

If you were in frigid, sub-freezing Wenatchee yesterday and wanted to warm up by 20F you could do it--by going up into the mountains.  


This morning, the Puget Sound lowlands are enshrouded in fog, but clear skies are only about 1000 feet above.  

Want proof?  Here is a picture from around 1200 ft in Bellevue, looking west, provided by Dr. Peter Benda.  Fog covers the lowlands, but blue skies are aloft.


Or this picture from the top of West Tiger 3 (2500 ft) by Dr. Steve Cobert.  Cougar Mountain is an island in a sea of fog and low clouds.


The pattern is confirmed by the visible satellite image at 8:16 AM this morning (below), with the western lowlands enshrouded by fog, as is the Columbia Basin.  But the coast is clear.


The origin of these sharp contrasts is strong high pressure, which has produced a super-inversion over the region.

The upper level (500 hPa, about 18,000 ft) for yesterday at 4 PM (shown below) clearly indicates a strong ridge of high pressure just offshore.   And just east of such ridges, very strong sinking occurs.


Such sinking produces what is known as a subsidence inversion.   An inversion is when temperatures INCREASE with height over some layer of the atmosphere, which is the inversion (opposite) of what normally occurs:  temperature decreasing with height.  

Why do high-pressure areas create inversions you ask?  

 Because sinking air is compressed and warmed.  The sinking is larger aloft but weakens towards the surface (because the ground is in the way!).    Also the clear skies aloft air enable radiational cooling from the surface before any fog forms.

Let me show you how impressive the inversion was this morning.  The radiosonde-based vertical sounding at Quilayute shows warming of about 18C (roughly 32F) in the lower few thousand feet (see below).  WOW.

And aircraft coming into and out of SeaTac airport measure temperatures, and this morning at 8 AM temperatures increases from the lower 30s near the surface to the 50s above 2000 ft.  Double wow.

Image from Seattle SnowWatch, funded by the City of Seattle

Hike to the top of Tiger Mountain today (at about 2500 ft) and you can have your lunch in bright sun and perhaps 60F, with your hike starting near freezing.  My kind of hike.

High pressure will be hanging around through Thursday, after which precipitation will return to the Northwest.  It has been a nice break from the rain, providing a chance for things to dry out a bit and lessening the chances for landslides and slope failures after a very wet period.
______________________________________

Important Update at 3:43 PM

With a strong inversion, there was a huge difference between the temperatures at Tiger Mountain Family Nudist Park --37F-- (elevation 646 ft) and Poo-Poo Point (about 1550 ft) -55F (see map below).   In fact, Poo Poo Point, which is known for hang gliding,  peaked at 57F.

So roughly 20F higher about 900 ft up.  A very strong inversion.

I suspect the Nudist colony folks may be moving up the hill to Poo Poo Point today for obvious reasons.  Stay tuned, this could get interesting!  

inversion have developed over the Northwest The Southern Oregon Coast Hits 79F as a Super-Inversion Develops over the Northwest






Comments

Post a Comment

Popular posts from this blog

The Time of Year You Can See the Air Move

Image
  Most of the time, you can not see the air move.   You can feel it, but the complex, turbulent motions are invisible to you, except when it interacts with leaves and branches on trees and plants. But for a few weeks of the year, the sky is full of small, cotton-like tuffs that like a natural MRI machine reveals the complex three-dimensional motions of the atmosphere.   Cottonwood season.  And we right in the middle of it.   Being cottonwood aware is of particular value this year.  It reveals the active dispersion and movement of air that makes the outdoors essentially COVID safe, and thus should be of some comfort for those nervous about transmission outside. Cottonwood seeds are embedded in small cotton-like fibers.   A million seeds weigh about 3 pounds.  Yes, each seed and tuff weights about .000003 pounds.   And that fact, plus the cottonwood tuff, means that these seeds fall VERY, VERY, VERY slowly.   So slowly that they are excellent markers for the three-dimensional flow of the
Read more

Why so little lightning in the Pacific Northwest? And a very nice weekend ahead.

Image
During the past 24-hours, there have been a few lightning strokes over the region (see below) but nothing to write home about (see below). It turns out that the Pacific Northwest and the remainder of the West Coast have some of the lowest frequencies of thunderstorms in the entire country (see below). But why?    My podcast provides the answer. And I also give the weekend forecast....and I think most will like what I have to say. To listen to my podcast, use the link below or access it through your favorite podcast service. Some major podcast servers:     Like the podcast? Support on Patreon 
Read more

Strong Atmosphere River Heads into British Columbia and Southeast Alaska

Image
While the Northwest has been drier than normal, it has been drenching wet a few hundred miles to the north. An unusually strong atmospheric river ....a long current of moisture stretching southward to the subtropics...has been in place for days, bringing large amounts of water vapor to Alaska.   And the atmospheric river will be in place for several more days, slowly moving southward. To illustrate, the scale and beauty of the atmospheric river, here is a water vapor satellite image for 11 AM today. The lighter areas have more water vapor.  You can see the current of moisture extending from near Hawaii into central BC.  This current is the result of low pressure over the Gulf of Alaska and high pressure offshore of California.   A forecast of total water vapor content in the atmosphere for 11 PM tonight shows a healthy atmospheric river (white and blue colors indicate the higher amounts of moisture). As this atmospheric river slams into the mountainous West Coast, the air is forced to
Read more